/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/lib/AST/ExprConstant.cpp

Bug Summary

File:	src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/lib/AST/ExprConstant.cpp
Warning:	line 5966, column 57 Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ExprConstant.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangAST/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangAST/obj/../include/clang/AST -I /usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangAST/../include -I /usr/src/gnu/usr.bin/clang/libclangAST/obj -I /usr/src/gnu/usr.bin/clang/libclangAST/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangAST/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/lib/AST/ExprConstant.cpp

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/lib/AST/ExprConstant.cpp

→

1//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the Expr constant evaluator.
10//
11// Constant expression evaluation produces four main results:
12//
13//  * A success/failure flag indicating whether constant folding was successful.
14//    This is the 'bool' return value used by most of the code in this file. A
15//    'false' return value indicates that constant folding has failed, and any
16//    appropriate diagnostic has already been produced.
17//
18//  * An evaluated result, valid only if constant folding has not failed.
19//
20//  * A flag indicating if evaluation encountered (unevaluated) side-effects.
21//    These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
22//    where it is possible to determine the evaluated result regardless.
23//
24//  * A set of notes indicating why the evaluation was not a constant expression
25//    (under the C++11 / C++1y rules only, at the moment), or, if folding failed
26//    too, why the expression could not be folded.
27//
28// If we are checking for a potential constant expression, failure to constant
29// fold a potential constant sub-expression will be indicated by a 'false'
30// return value (the expression could not be folded) and no diagnostic (the
31// expression is not necessarily non-constant).
32//
33//===----------------------------------------------------------------------===//

35#include "Interp/Context.h"
36#include "Interp/Frame.h"
37#include "Interp/State.h"
38#include "clang/AST/APValue.h"
39#include "clang/AST/ASTContext.h"
40#include "clang/AST/ASTDiagnostic.h"
41#include "clang/AST/ASTLambda.h"
42#include "clang/AST/Attr.h"
43#include "clang/AST/CXXInheritance.h"
44#include "clang/AST/CharUnits.h"
45#include "clang/AST/CurrentSourceLocExprScope.h"
46#include "clang/AST/Expr.h"
47#include "clang/AST/OSLog.h"
48#include "clang/AST/OptionalDiagnostic.h"
49#include "clang/AST/RecordLayout.h"
50#include "clang/AST/StmtVisitor.h"
51#include "clang/AST/TypeLoc.h"
52#include "clang/Basic/Builtins.h"
53#include "clang/Basic/TargetInfo.h"
54#include "llvm/ADT/APFixedPoint.h"
55#include "llvm/ADT/Optional.h"
56#include "llvm/ADT/SmallBitVector.h"
57#include "llvm/Support/Debug.h"
58#include "llvm/Support/SaveAndRestore.h"
59#include "llvm/Support/raw_ostream.h"
60#include <cstring>
61#include <functional>

63#define DEBUG_TYPE"exprconstant" "exprconstant"

65using namespace clang;
66using llvm::APFixedPoint;
67using llvm::APInt;
68using llvm::APSInt;
69using llvm::APFloat;
70using llvm::FixedPointSemantics;
71using llvm::Optional;

73namespace {
struct LValue;
class CallStackFrame;
class EvalInfo;

using SourceLocExprScopeGuard =
    CurrentSourceLocExprScope::SourceLocExprScopeGuard;

static QualType getType(APValue::LValueBase B) {
  return B.getType();
}

/// Get an LValue path entry, which is known to not be an array index, as a
/// field declaration.
static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
  return dyn_cast_or_null<FieldDecl>(E.getAsBaseOrMember().getPointer());
}
/// Get an LValue path entry, which is known to not be an array index, as a
/// base class declaration.
static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
  return dyn_cast_or_null<CXXRecordDecl>(E.getAsBaseOrMember().getPointer());
}
/// Determine whether this LValue path entry for a base class names a virtual
/// base class.
static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
  return E.getAsBaseOrMember().getInt();
}

/// Given an expression, determine the type used to store the result of
/// evaluating that expression.
static QualType getStorageType(const ASTContext &Ctx, const Expr *E) {
  if (E->isPRValue())
    return E->getType();
  return Ctx.getLValueReferenceType(E->getType());
}

/// Given a CallExpr, try to get the alloc_size attribute. May return null.
static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
  if (const FunctionDecl *DirectCallee = CE->getDirectCallee())
    return DirectCallee->getAttr<AllocSizeAttr>();
  if (const Decl *IndirectCallee = CE->getCalleeDecl())
    return IndirectCallee->getAttr<AllocSizeAttr>();
  return nullptr;
}

/// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
/// This will look through a single cast.
///
/// Returns null if we couldn't unwrap a function with alloc_size.
static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
  if (!E->getType()->isPointerType())
    return nullptr;

  E = E->IgnoreParens();
  // If we're doing a variable assignment from e.g. malloc(N), there will
  // probably be a cast of some kind. In exotic cases, we might also see a
  // top-level ExprWithCleanups. Ignore them either way.
  if (const auto *FE = dyn_cast<FullExpr>(E))
    E = FE->getSubExpr()->IgnoreParens();

  if (const auto *Cast = dyn_cast<CastExpr>(E))
    E = Cast->getSubExpr()->IgnoreParens();

  if (const auto *CE = dyn_cast<CallExpr>(E))
    return getAllocSizeAttr(CE) ? CE : nullptr;
  return nullptr;
}

/// Determines whether or not the given Base contains a call to a function
/// with the alloc_size attribute.
static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
  const auto *E = Base.dyn_cast<const Expr *>();
  return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
}

/// Determines whether the given kind of constant expression is only ever
/// used for name mangling. If so, it's permitted to reference things that we
/// can't generate code for (in particular, dllimported functions).
static bool isForManglingOnly(ConstantExprKind Kind) {
  switch (Kind) {
  case ConstantExprKind::Normal:
  case ConstantExprKind::ClassTemplateArgument:
  case ConstantExprKind::ImmediateInvocation:
    // Note that non-type template arguments of class type are emitted as
    // template parameter objects.
    return false;

  case ConstantExprKind::NonClassTemplateArgument:
    return true;
  }
  llvm_unreachable("unknown ConstantExprKind")__builtin_unreachable();
}

static bool isTemplateArgument(ConstantExprKind Kind) {
  switch (Kind) {
  case ConstantExprKind::Normal:
  case ConstantExprKind::ImmediateInvocation:
    return false;

  case ConstantExprKind::ClassTemplateArgument:
  case ConstantExprKind::NonClassTemplateArgument:
    return true;
  }
  llvm_unreachable("unknown ConstantExprKind")__builtin_unreachable();
}

/// The bound to claim that an array of unknown bound has.
/// The value in MostDerivedArraySize is undefined in this case. So, set it
/// to an arbitrary value that's likely to loudly break things if it's used.
static const uint64_t AssumedSizeForUnsizedArray =
    std::numeric_limits<uint64_t>::max() / 2;

/// Determines if an LValue with the given LValueBase will have an unsized
/// array in its designator.
/// Find the path length and type of the most-derived subobject in the given
/// path, and find the size of the containing array, if any.
static unsigned
findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
                         ArrayRef<APValue::LValuePathEntry> Path,
                         uint64_t &ArraySize, QualType &Type, bool &IsArray,
                         bool &FirstEntryIsUnsizedArray) {
  // This only accepts LValueBases from APValues, and APValues don't support
  // arrays that lack size info.
  assert(!isBaseAnAllocSizeCall(Base) &&((void)0)
         "Unsized arrays shouldn't appear here")((void)0);
  unsigned MostDerivedLength = 0;
  Type = getType(Base);

  for (unsigned I = 0, N = Path.size(); I != N; ++I) {
    if (Type->isArrayType()) {
      const ArrayType *AT = Ctx.getAsArrayType(Type);
      Type = AT->getElementType();
      MostDerivedLength = I + 1;
      IsArray = true;

      if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
        ArraySize = CAT->getSize().getZExtValue();
      } else {
        assert(I == 0 && "unexpected unsized array designator")((void)0);
        FirstEntryIsUnsizedArray = true;
        ArraySize = AssumedSizeForUnsizedArray;
      }
    } else if (Type->isAnyComplexType()) {
      const ComplexType *CT = Type->castAs<ComplexType>();
      Type = CT->getElementType();
      ArraySize = 2;
      MostDerivedLength = I + 1;
      IsArray = true;
    } else if (const FieldDecl *FD = getAsField(Path[I])) {
      Type = FD->getType();
      ArraySize = 0;
      MostDerivedLength = I + 1;
      IsArray = false;
    } else {
      // Path[I] describes a base class.
      ArraySize = 0;
      IsArray = false;
    }
  }
  return MostDerivedLength;
}

/// A path from a glvalue to a subobject of that glvalue.
struct SubobjectDesignator {
  /// True if the subobject was named in a manner not supported by C++11. Such
  /// lvalues can still be folded, but they are not core constant expressions
  /// and we cannot perform lvalue-to-rvalue conversions on them.
  unsigned Invalid : 1;

  /// Is this a pointer one past the end of an object?
  unsigned IsOnePastTheEnd : 1;

  /// Indicator of whether the first entry is an unsized array.
  unsigned FirstEntryIsAnUnsizedArray : 1;

  /// Indicator of whether the most-derived object is an array element.
  unsigned MostDerivedIsArrayElement : 1;

  /// The length of the path to the most-derived object of which this is a
  /// subobject.
  unsigned MostDerivedPathLength : 28;

  /// The size of the array of which the most-derived object is an element.
  /// This will always be 0 if the most-derived object is not an array
  /// element. 0 is not an indicator of whether or not the most-derived object
  /// is an array, however, because 0-length arrays are allowed.
  ///
  /// If the current array is an unsized array, the value of this is
  /// undefined.
  uint64_t MostDerivedArraySize;

  /// The type of the most derived object referred to by this address.
  QualType MostDerivedType;

  typedef APValue::LValuePathEntry PathEntry;

  /// The entries on the path from the glvalue to the designated subobject.
  SmallVector<PathEntry, 8> Entries;

  SubobjectDesignator() : Invalid(true) {}

  explicit SubobjectDesignator(QualType T)
      : Invalid(false), IsOnePastTheEnd(false),
        FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
        MostDerivedPathLength(0), MostDerivedArraySize(0),
        MostDerivedType(T) {}

  SubobjectDesignator(ASTContext &Ctx, const APValue &V)
      : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
        FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
        MostDerivedPathLength(0), MostDerivedArraySize(0) {
    assert(V.isLValue() && "Non-LValue used to make an LValue designator?")((void)0);
    if (!Invalid) {
      IsOnePastTheEnd = V.isLValueOnePastTheEnd();
      ArrayRef<PathEntry> VEntries = V.getLValuePath();
      Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
      if (V.getLValueBase()) {
        bool IsArray = false;
        bool FirstIsUnsizedArray = false;
        MostDerivedPathLength = findMostDerivedSubobject(
            Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
            MostDerivedType, IsArray, FirstIsUnsizedArray);
        MostDerivedIsArrayElement = IsArray;
        FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
      }
    }
  }

  void truncate(ASTContext &Ctx, APValue::LValueBase Base,
                unsigned NewLength) {
    if (Invalid)
      return;

    assert(Base && "cannot truncate path for null pointer")((void)0);
    assert(NewLength <= Entries.size() && "not a truncation")((void)0);

    if (NewLength == Entries.size())
      return;
    Entries.resize(NewLength);

    bool IsArray = false;
    bool FirstIsUnsizedArray = false;
    MostDerivedPathLength = findMostDerivedSubobject(
        Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray,
        FirstIsUnsizedArray);
    MostDerivedIsArrayElement = IsArray;
    FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
  }

  void setInvalid() {
    Invalid = true;
    Entries.clear();
  }

  /// Determine whether the most derived subobject is an array without a
  /// known bound.
  bool isMostDerivedAnUnsizedArray() const {
    assert(!Invalid && "Calling this makes no sense on invalid designators")((void)0);
    return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
  }

  /// Determine what the most derived array's size is. Results in an assertion
  /// failure if the most derived array lacks a size.
  uint64_t getMostDerivedArraySize() const {
    assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size")((void)0);
    return MostDerivedArraySize;
  }

  /// Determine whether this is a one-past-the-end pointer.
  bool isOnePastTheEnd() const {
    assert(!Invalid)((void)0);
    if (IsOnePastTheEnd)
      return true;
    if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
        Entries[MostDerivedPathLength - 1].getAsArrayIndex() ==
            MostDerivedArraySize)
      return true;
    return false;
  }

  /// Get the range of valid index adjustments in the form
  ///   {maximum value that can be subtracted from this pointer,
  ///    maximum value that can be added to this pointer}
  std::pair<uint64_t, uint64_t> validIndexAdjustments() {
    if (Invalid || isMostDerivedAnUnsizedArray())
      return {0, 0};

    // [expr.add]p4: For the purposes of these operators, a pointer to a
    // nonarray object behaves the same as a pointer to the first element of
    // an array of length one with the type of the object as its element type.
    bool IsArray = MostDerivedPathLength == Entries.size() &&
                   MostDerivedIsArrayElement;
    uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
                                  : (uint64_t)IsOnePastTheEnd;
    uint64_t ArraySize =
        IsArray ? getMostDerivedArraySize() : (uint64_t)1;
    return {ArrayIndex, ArraySize - ArrayIndex};
  }

  /// Check that this refers to a valid subobject.
  bool isValidSubobject() const {
    if (Invalid)
      return false;
    return !isOnePastTheEnd();
  }
  /// Check that this refers to a valid subobject, and if not, produce a
  /// relevant diagnostic and set the designator as invalid.
  bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);

  /// Get the type of the designated object.
  QualType getType(ASTContext &Ctx) const {
    assert(!Invalid && "invalid designator has no subobject type")((void)0);
    return MostDerivedPathLength == Entries.size()
               ? MostDerivedType
               : Ctx.getRecordType(getAsBaseClass(Entries.back()));
  }

  /// Update this designator to refer to the first element within this array.
  void addArrayUnchecked(const ConstantArrayType *CAT) {
    Entries.push_back(PathEntry::ArrayIndex(0));

    // This is a most-derived object.
    MostDerivedType = CAT->getElementType();
    MostDerivedIsArrayElement = true;
    MostDerivedArraySize = CAT->getSize().getZExtValue();
    MostDerivedPathLength = Entries.size();
  }
  /// Update this designator to refer to the first element within the array of
  /// elements of type T. This is an array of unknown size.
  void addUnsizedArrayUnchecked(QualType ElemTy) {
    Entries.push_back(PathEntry::ArrayIndex(0));

    MostDerivedType = ElemTy;
    MostDerivedIsArrayElement = true;
    // The value in MostDerivedArraySize is undefined in this case. So, set it
    // to an arbitrary value that's likely to loudly break things if it's
    // used.
    MostDerivedArraySize = AssumedSizeForUnsizedArray;
    MostDerivedPathLength = Entries.size();
  }
  /// Update this designator to refer to the given base or member of this
  /// object.
  void addDeclUnchecked(const Decl *D, bool Virtual = false) {
    Entries.push_back(APValue::BaseOrMemberType(D, Virtual));

    // If this isn't a base class, it's a new most-derived object.
    if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
      MostDerivedType = FD->getType();
      MostDerivedIsArrayElement = false;
      MostDerivedArraySize = 0;
      MostDerivedPathLength = Entries.size();
    }
  }
  /// Update this designator to refer to the given complex component.
  void addComplexUnchecked(QualType EltTy, bool Imag) {
    Entries.push_back(PathEntry::ArrayIndex(Imag));

    // This is technically a most-derived object, though in practice this
    // is unlikely to matter.
    MostDerivedType = EltTy;
    MostDerivedIsArrayElement = true;
    MostDerivedArraySize = 2;
    MostDerivedPathLength = Entries.size();
  }
  void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E);
  void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
                                 const APSInt &N);
  /// Add N to the address of this subobject.
  void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
    if (Invalid || !N) return;
    uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue();
    if (isMostDerivedAnUnsizedArray()) {
      diagnoseUnsizedArrayPointerArithmetic(Info, E);
      // Can't verify -- trust that the user is doing the right thing (or if
      // not, trust that the caller will catch the bad behavior).
      // FIXME: Should we reject if this overflows, at least?
      Entries.back() = PathEntry::ArrayIndex(
          Entries.back().getAsArrayIndex() + TruncatedN);
      return;
    }

    // [expr.add]p4: For the purposes of these operators, a pointer to a
    // nonarray object behaves the same as a pointer to the first element of
    // an array of length one with the type of the object as its element type.
    bool IsArray = MostDerivedPathLength == Entries.size() &&
                   MostDerivedIsArrayElement;
    uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
                                  : (uint64_t)IsOnePastTheEnd;
    uint64_t ArraySize =
        IsArray ? getMostDerivedArraySize() : (uint64_t)1;

    if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
      // Calculate the actual index in a wide enough type, so we can include
      // it in the note.
      N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65));
      (llvm::APInt&)N += ArrayIndex;
      assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index")((void)0);
      diagnosePointerArithmetic(Info, E, N);
      setInvalid();
      return;
    }

    ArrayIndex += TruncatedN;
    assert(ArrayIndex <= ArraySize &&((void)0)
           "bounds check succeeded for out-of-bounds index")((void)0);

    if (IsArray)
      Entries.back() = PathEntry::ArrayIndex(ArrayIndex);
    else
      IsOnePastTheEnd = (ArrayIndex != 0);
  }
};

/// A scope at the end of which an object can need to be destroyed.
enum class ScopeKind {
  Block,
  FullExpression,
  Call
};

/// A reference to a particular call and its arguments.
struct CallRef {
  CallRef() : OrigCallee(), CallIndex(0), Version() {}
  CallRef(const FunctionDecl *Callee, unsigned CallIndex, unsigned Version)
      : OrigCallee(Callee), CallIndex(CallIndex), Version(Version) {}

  explicit operator bool() const { return OrigCallee; }

  /// Get the parameter that the caller initialized, corresponding to the
  /// given parameter in the callee.
  const ParmVarDecl *getOrigParam(const ParmVarDecl *PVD) const {
    return OrigCallee ? OrigCallee->getParamDecl(PVD->getFunctionScopeIndex())
                      : PVD;
  }

  /// The callee at the point where the arguments were evaluated. This might
  /// be different from the actual callee (a different redeclaration, or a
  /// virtual override), but this function's parameters are the ones that
  /// appear in the parameter map.
  const FunctionDecl *OrigCallee;
  /// The call index of the frame that holds the argument values.
  unsigned CallIndex;
  /// The version of the parameters corresponding to this call.
  unsigned Version;
};

/// A stack frame in the constexpr call stack.
class CallStackFrame : public interp::Frame {
public:
  EvalInfo &Info;

  /// Parent - The caller of this stack frame.
  CallStackFrame *Caller;

  /// Callee - The function which was called.
  const FunctionDecl *Callee;

  /// This - The binding for the this pointer in this call, if any.
  const LValue *This;

  /// Information on how to find the arguments to this call. Our arguments
  /// are stored in our parent's CallStackFrame, using the ParmVarDecl* as a
  /// key and this value as the version.
  CallRef Arguments;

  /// Source location information about the default argument or default
  /// initializer expression we're evaluating, if any.
  CurrentSourceLocExprScope CurSourceLocExprScope;

  // Note that we intentionally use std::map here so that references to
  // values are stable.
  typedef std::pair<const void *, unsigned> MapKeyTy;
  typedef std::map<MapKeyTy, APValue> MapTy;
  /// Temporaries - Temporary lvalues materialized within this stack frame.
  MapTy Temporaries;

  /// CallLoc - The location of the call expression for this call.
  SourceLocation CallLoc;

  /// Index - The call index of this call.
  unsigned Index;

  /// The stack of integers for tracking version numbers for temporaries.
  SmallVector<unsigned, 2> TempVersionStack = {1};
  unsigned CurTempVersion = TempVersionStack.back();

  unsigned getTempVersion() const { return TempVersionStack.back(); }

  void pushTempVersion() {
    TempVersionStack.push_back(++CurTempVersion);
  }

  void popTempVersion() {
    TempVersionStack.pop_back();
  }

  CallRef createCall(const FunctionDecl *Callee) {
    return {Callee, Index, ++CurTempVersion};
  }

  // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact
  // on the overall stack usage of deeply-recursing constexpr evaluations.
  // (We should cache this map rather than recomputing it repeatedly.)
  // But let's try this and see how it goes; we can look into caching the map
  // as a later change.

  /// LambdaCaptureFields - Mapping from captured variables/this to
  /// corresponding data members in the closure class.
  llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields;
  FieldDecl *LambdaThisCaptureField;

  CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
                 const FunctionDecl *Callee, const LValue *This,
                 CallRef Arguments);
  ~CallStackFrame();

  // Return the temporary for Key whose version number is Version.
  APValue *getTemporary(const void *Key, unsigned Version) {
    MapKeyTy KV(Key, Version);
    auto LB = Temporaries.lower_bound(KV);
    if (LB != Temporaries.end() && LB->first == KV)
60
←
Assuming the condition is true→
61
←
Taking true branch→
      return &LB->second;
62
←
Returning pointer, which participates in a condition later→
    // Pair (Key,Version) wasn't found in the map. Check that no elements
    // in the map have 'Key' as their key.
    assert((LB == Temporaries.end() || LB->first.first != Key) &&((void)0)
           (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) &&((void)0)
           "Element with key 'Key' found in map")((void)0);
    return nullptr;
  }

  // Return the current temporary for Key in the map.
  APValue *getCurrentTemporary(const void *Key) {
    auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX(2147483647 *2U +1U)));
    if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
      return &std::prev(UB)->second;
    return nullptr;
  }

  // Return the version number of the current temporary for Key.
  unsigned getCurrentTemporaryVersion(const void *Key) const {
    auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX(2147483647 *2U +1U)));
    if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
      return std::prev(UB)->first.second;
    return 0;
  }

  /// Allocate storage for an object of type T in this stack frame.
  /// Populates LV with a handle to the created object. Key identifies
  /// the temporary within the stack frame, and must not be reused without
  /// bumping the temporary version number.
  template<typename KeyT>
  APValue &createTemporary(const KeyT *Key, QualType T,
                           ScopeKind Scope, LValue &LV);

  /// Allocate storage for a parameter of a function call made in this frame.
  APValue &createParam(CallRef Args, const ParmVarDecl *PVD, LValue &LV);

  void describe(llvm::raw_ostream &OS) override;

  Frame *getCaller() const override { return Caller; }
  SourceLocation getCallLocation() const override { return CallLoc; }
  const FunctionDecl *getCallee() const override { return Callee; }

  bool isStdFunction() const {
    for (const DeclContext *DC = Callee; DC; DC = DC->getParent())
      if (DC->isStdNamespace())
        return true;
    return false;
  }

private:
  APValue &createLocal(APValue::LValueBase Base, const void *Key, QualType T,
                       ScopeKind Scope);
};

/// Temporarily override 'this'.
class ThisOverrideRAII {
public:
  ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
      : Frame(Frame), OldThis(Frame.This) {
    if (Enable)
      Frame.This = NewThis;
  }
  ~ThisOverrideRAII() {
    Frame.This = OldThis;
  }
private:
  CallStackFrame &Frame;
  const LValue *OldThis;
};
663}

665static bool HandleDestruction(EvalInfo &Info, const Expr *E,
                            const LValue &This, QualType ThisType);
667static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
                            APValue::LValueBase LVBase, APValue &Value,
                            QualType T);

671namespace {
/// A cleanup, and a flag indicating whether it is lifetime-extended.
class Cleanup {
  llvm::PointerIntPair<APValue*, 2, ScopeKind> Value;
  APValue::LValueBase Base;
  QualType T;

public:
  Cleanup(APValue *Val, APValue::LValueBase Base, QualType T,
          ScopeKind Scope)
      : Value(Val, Scope), Base(Base), T(T) {}

  /// Determine whether this cleanup should be performed at the end of the
  /// given kind of scope.
  bool isDestroyedAtEndOf(ScopeKind K) const {
    return (int)Value.getInt() >= (int)K;
  }
  bool endLifetime(EvalInfo &Info, bool RunDestructors) {
    if (RunDestructors) {
      SourceLocation Loc;
      if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
        Loc = VD->getLocation();
      else if (const Expr *E = Base.dyn_cast<const Expr*>())
        Loc = E->getExprLoc();
      return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T);
    }
    *Value.getPointer() = APValue();
    return true;
  }

  bool hasSideEffect() {
    return T.isDestructedType();
  }
};

/// A reference to an object whose construction we are currently evaluating.
struct ObjectUnderConstruction {
  APValue::LValueBase Base;
  ArrayRef<APValue::LValuePathEntry> Path;
  friend bool operator==(const ObjectUnderConstruction &LHS,
                         const ObjectUnderConstruction &RHS) {
    return LHS.Base == RHS.Base && LHS.Path == RHS.Path;
  }
  friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) {
    return llvm::hash_combine(Obj.Base, Obj.Path);
  }
};
enum class ConstructionPhase {
  None,
  Bases,
  AfterBases,
  AfterFields,
  Destroying,
  DestroyingBases
};
726}

728namespace llvm {
729template<> struct DenseMapInfo<ObjectUnderConstruction> {
using Base = DenseMapInfo<APValue::LValueBase>;
static ObjectUnderConstruction getEmptyKey() {
  return {Base::getEmptyKey(), {}}; }
static ObjectUnderConstruction getTombstoneKey() {
  return {Base::getTombstoneKey(), {}};
}
static unsigned getHashValue(const ObjectUnderConstruction &Object) {
  return hash_value(Object);
}
static bool isEqual(const ObjectUnderConstruction &LHS,
                    const ObjectUnderConstruction &RHS) {
  return LHS == RHS;
}
743};
744}

746namespace {
/// A dynamically-allocated heap object.
struct DynAlloc {
  /// The value of this heap-allocated object.
  APValue Value;
  /// The allocating expression; used for diagnostics. Either a CXXNewExpr
  /// or a CallExpr (the latter is for direct calls to operator new inside
  /// std::allocator<T>::allocate).
  const Expr *AllocExpr = nullptr;

  enum Kind {
    New,
    ArrayNew,
    StdAllocator
  };

  /// Get the kind of the allocation. This must match between allocation
  /// and deallocation.
  Kind getKind() const {
    if (auto *NE = dyn_cast<CXXNewExpr>(AllocExpr))
      return NE->isArray() ? ArrayNew : New;
    assert(isa<CallExpr>(AllocExpr))((void)0);
    return StdAllocator;
  }
};

struct DynAllocOrder {
  bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const {
    return L.getIndex() < R.getIndex();
  }
};

/// EvalInfo - This is a private struct used by the evaluator to capture
/// information about a subexpression as it is folded.  It retains information
/// about the AST context, but also maintains information about the folded
/// expression.
///
/// If an expression could be evaluated, it is still possible it is not a C
/// "integer constant expression" or constant expression.  If not, this struct
/// captures information about how and why not.
///
/// One bit of information passed *into* the request for constant folding
/// indicates whether the subexpression is "evaluated" or not according to C
/// rules.  For example, the RHS of (0 && foo()) is not evaluated.  We can
/// evaluate the expression regardless of what the RHS is, but C only allows
/// certain things in certain situations.
class EvalInfo : public interp::State {
public:
  ASTContext &Ctx;

  /// EvalStatus - Contains information about the evaluation.
  Expr::EvalStatus &EvalStatus;

  /// CurrentCall - The top of the constexpr call stack.
  CallStackFrame *CurrentCall;

  /// CallStackDepth - The number of calls in the call stack right now.
  unsigned CallStackDepth;

  /// NextCallIndex - The next call index to assign.
  unsigned NextCallIndex;

  /// StepsLeft - The remaining number of evaluation steps we're permitted
  /// to perform. This is essentially a limit for the number of statements
  /// we will evaluate.
  unsigned StepsLeft;

  /// Enable the experimental new constant interpreter. If an expression is
  /// not supported by the interpreter, an error is triggered.
  bool EnableNewConstInterp;

  /// BottomFrame - The frame in which evaluation started. This must be
  /// initialized after CurrentCall and CallStackDepth.
  CallStackFrame BottomFrame;

  /// A stack of values whose lifetimes end at the end of some surrounding
  /// evaluation frame.
  llvm::SmallVector<Cleanup, 16> CleanupStack;

  /// EvaluatingDecl - This is the declaration whose initializer is being
  /// evaluated, if any.
  APValue::LValueBase EvaluatingDecl;

  enum class EvaluatingDeclKind {
    None,
    /// We're evaluating the construction of EvaluatingDecl.
    Ctor,
    /// We're evaluating the destruction of EvaluatingDecl.
    Dtor,
  };
  EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None;

  /// EvaluatingDeclValue - This is the value being constructed for the
  /// declaration whose initializer is being evaluated, if any.
  APValue *EvaluatingDeclValue;

  /// Set of objects that are currently being constructed.
  llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase>
      ObjectsUnderConstruction;

  /// Current heap allocations, along with the location where each was
  /// allocated. We use std::map here because we need stable addresses
  /// for the stored APValues.
  std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs;

  /// The number of heap allocations performed so far in this evaluation.
  unsigned NumHeapAllocs = 0;

  struct EvaluatingConstructorRAII {
    EvalInfo &EI;
    ObjectUnderConstruction Object;
    bool DidInsert;
    EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object,
                              bool HasBases)
        : EI(EI), Object(Object) {
      DidInsert =
          EI.ObjectsUnderConstruction
              .insert({Object, HasBases ? ConstructionPhase::Bases
                                        : ConstructionPhase::AfterBases})
              .second;
    }
    void finishedConstructingBases() {
      EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases;
    }
    void finishedConstructingFields() {
      EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields;
    }
    ~EvaluatingConstructorRAII() {
      if (DidInsert) EI.ObjectsUnderConstruction.erase(Object);
    }
  };

  struct EvaluatingDestructorRAII {
    EvalInfo &EI;
    ObjectUnderConstruction Object;
    bool DidInsert;
    EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object)
        : EI(EI), Object(Object) {
      DidInsert = EI.ObjectsUnderConstruction
                      .insert({Object, ConstructionPhase::Destroying})
                      .second;
    }
    void startedDestroyingBases() {
      EI.ObjectsUnderConstruction[Object] =
          ConstructionPhase::DestroyingBases;
    }
    ~EvaluatingDestructorRAII() {
      if (DidInsert)
        EI.ObjectsUnderConstruction.erase(Object);
    }
  };

  ConstructionPhase
  isEvaluatingCtorDtor(APValue::LValueBase Base,
                       ArrayRef<APValue::LValuePathEntry> Path) {
    return ObjectsUnderConstruction.lookup({Base, Path});
  }

  /// If we're currently speculatively evaluating, the outermost call stack
  /// depth at which we can mutate state, otherwise 0.
  unsigned SpeculativeEvaluationDepth = 0;

  /// The current array initialization index, if we're performing array
  /// initialization.
  uint64_t ArrayInitIndex = -1;

  /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
  /// notes attached to it will also be stored, otherwise they will not be.
  bool HasActiveDiagnostic;

  /// Have we emitted a diagnostic explaining why we couldn't constant
  /// fold (not just why it's not strictly a constant expression)?
  bool HasFoldFailureDiagnostic;

  /// Whether or not we're in a context where the front end requires a
  /// constant value.
  bool InConstantContext;

  /// Whether we're checking that an expression is a potential constant
  /// expression. If so, do not fail on constructs that could become constant
  /// later on (such as a use of an undefined global).
  bool CheckingPotentialConstantExpression = false;

  /// Whether we're checking for an expression that has undefined behavior.
  /// If so, we will produce warnings if we encounter an operation that is
  /// always undefined.
  ///
  /// Note that we still need to evaluate the expression normally when this
  /// is set; this is used when evaluating ICEs in C.
  bool CheckingForUndefinedBehavior = false;

  enum EvaluationMode {
    /// Evaluate as a constant expression. Stop if we find that the expression
    /// is not a constant expression.
    EM_ConstantExpression,

    /// Evaluate as a constant expression. Stop if we find that the expression
    /// is not a constant expression. Some expressions can be retried in the
    /// optimizer if we don't constant fold them here, but in an unevaluated
    /// context we try to fold them immediately since the optimizer never
    /// gets a chance to look at it.
    EM_ConstantExpressionUnevaluated,

    /// Fold the expression to a constant. Stop if we hit a side-effect that
    /// we can't model.
    EM_ConstantFold,

    /// Evaluate in any way we know how. Don't worry about side-effects that
    /// can't be modeled.
    EM_IgnoreSideEffects,
  } EvalMode;

  /// Are we checking whether the expression is a potential constant
  /// expression?
  bool checkingPotentialConstantExpression() const override  {
    return CheckingPotentialConstantExpression;
19
←
Returning the value 1, which participates in a condition later→
  }

  /// Are we checking an expression for overflow?
  // FIXME: We should check for any kind of undefined or suspicious behavior
  // in such constructs, not just overflow.
  bool checkingForUndefinedBehavior() const override {
    return CheckingForUndefinedBehavior;
  }

  EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
      : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
        CallStackDepth(0), NextCallIndex(1),
        StepsLeft(C.getLangOpts().ConstexprStepLimit),
        EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp),
        BottomFrame(*this, SourceLocation(), nullptr, nullptr, CallRef()),
4
←
Calling constructor for 'CallStackFrame'→
5
←
Returning from constructor for 'CallStackFrame'→
        EvaluatingDecl((const ValueDecl *)nullptr),
        EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
        HasFoldFailureDiagnostic(false), InConstantContext(false),
        EvalMode(Mode) {}

  ~EvalInfo() {
    discardCleanups();
  }

  void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value,
                         EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) {
    EvaluatingDecl = Base;
    IsEvaluatingDecl = EDK;
    EvaluatingDeclValue = &Value;
  }

  bool CheckCallLimit(SourceLocation Loc) {
    // Don't perform any constexpr calls (other than the call we're checking)
    // when checking a potential constant expression.
    if (checkingPotentialConstantExpression() && CallStackDepth > 1)
18
←
Calling 'EvalInfo::checkingPotentialConstantExpression'→
20
←
Returning from 'EvalInfo::checkingPotentialConstantExpression'→
21
←
Assuming field 'CallStackDepth' is <= 1→
22
←
Taking false branch→
      return false;
    if (NextCallIndex == 0) {
23
←
Assuming field 'NextCallIndex' is not equal to 0→
24
←
Taking false branch→
      // NextCallIndex has wrapped around.
      FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
      return false;
    }
    if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
25
←
Assuming field 'CallStackDepth' is <= field 'ConstexprCallDepth'→
26
←
Taking true branch→
      return true;
27
←
Returning the value 1, which participates in a condition later→
    FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
      << getLangOpts().ConstexprCallDepth;
    return false;
  }

  std::pair<CallStackFrame *, unsigned>
  getCallFrameAndDepth(unsigned CallIndex) {
    assert(CallIndex && "no call index in getCallFrameAndDepth")((void)0);
    // We will eventually hit BottomFrame, which has Index 1, so Frame can't
    // be null in this loop.
    unsigned Depth = CallStackDepth;
    CallStackFrame *Frame = CurrentCall;
    while (Frame->Index > CallIndex) {
      Frame = Frame->Caller;
      --Depth;
    }
    if (Frame->Index == CallIndex)
      return {Frame, Depth};
    return {nullptr, 0};
  }

  bool nextStep(const Stmt *S) {
    if (!StepsLeft) {
      FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded);
      return false;
    }
    --StepsLeft;
    return true;
  }

  APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV);

  Optional<DynAlloc*> lookupDynamicAlloc(DynamicAllocLValue DA) {
    Optional<DynAlloc*> Result;
    auto It = HeapAllocs.find(DA);
    if (It != HeapAllocs.end())
      Result = &It->second;
    return Result;
  }

  /// Get the allocated storage for the given parameter of the given call.
  APValue *getParamSlot(CallRef Call, const ParmVarDecl *PVD) {
    CallStackFrame *Frame = getCallFrameAndDepth(Call.CallIndex).first;
    return Frame57.1
'Frame' is non-null
1
'Frame' is non-null
1
'Frame' is non-null
1
'Frame' is non-null
1
'Frame' is non-null
1
'Frame' is non-null
 ? Frame->getTemporary(Call.getOrigParam(PVD), Call.Version)
58
←
'?' condition is true→
59
←
Calling 'CallStackFrame::getTemporary'→
63
←
Returning from 'CallStackFrame::getTemporary'→
64
←
Returning pointer, which participates in a condition later→
                 : nullptr;
  }

  /// Information about a stack frame for std::allocator<T>::[de]allocate.
  struct StdAllocatorCaller {
    unsigned FrameIndex;
    QualType ElemType;
    explicit operator bool() const { return FrameIndex != 0; };
  };

  StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const {
    for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame;
         Call = Call->Caller) {
      const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Call->Callee);
      if (!MD)
        continue;
      const IdentifierInfo *FnII = MD->getIdentifier();
      if (!FnII || !FnII->isStr(FnName))
        continue;

      const auto *CTSD =
          dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent());
      if (!CTSD)
        continue;

      const IdentifierInfo *ClassII = CTSD->getIdentifier();
      const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
      if (CTSD->isInStdNamespace() && ClassII &&
          ClassII->isStr("allocator") && TAL.size() >= 1 &&
          TAL[0].getKind() == TemplateArgument::Type)
        return {Call->Index, TAL[0].getAsType()};
    }

    return {};
  }

  void performLifetimeExtension() {
    // Disable the cleanups for lifetime-extended temporaries.
    CleanupStack.erase(std::remove_if(CleanupStack.begin(),
                                      CleanupStack.end(),
                                      [](Cleanup &C) {
                                        return !C.isDestroyedAtEndOf(
                                            ScopeKind::FullExpression);
                                      }),
                       CleanupStack.end());
   }

  /// Throw away any remaining cleanups at the end of evaluation. If any
  /// cleanups would have had a side-effect, note that as an unmodeled
  /// side-effect and return false. Otherwise, return true.
  bool discardCleanups() {
    for (Cleanup &C : CleanupStack) {
      if (C.hasSideEffect() && !noteSideEffect()) {
        CleanupStack.clear();
        return false;
      }
    }
    CleanupStack.clear();
    return true;
  }

private:
  interp::Frame *getCurrentFrame() override { return CurrentCall; }
  const interp::Frame *getBottomFrame() const override { return &BottomFrame; }

  bool hasActiveDiagnostic() override { return HasActiveDiagnostic; }
  void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; }

  void setFoldFailureDiagnostic(bool Flag) override {
    HasFoldFailureDiagnostic = Flag;
  }

  Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; }

  ASTContext &getCtx() const override { return Ctx; }

  // If we have a prior diagnostic, it will be noting that the expression
  // isn't a constant expression. This diagnostic is more important,
  // unless we require this evaluation to produce a constant expression.
  //
  // FIXME: We might want to show both diagnostics to the user in
  // EM_ConstantFold mode.
  bool hasPriorDiagnostic() override {
    if (!EvalStatus.Diag->empty()) {
      switch (EvalMode) {
      case EM_ConstantFold:
      case EM_IgnoreSideEffects:
        if (!HasFoldFailureDiagnostic)
          break;
        // We've already failed to fold something. Keep that diagnostic.
        LLVM_FALLTHROUGH[[gnu::fallthrough]];
      case EM_ConstantExpression:
      case EM_ConstantExpressionUnevaluated:
        setActiveDiagnostic(false);
        return true;
      }
    }
    return false;
  }

  unsigned getCallStackDepth() override { return CallStackDepth; }

public:
  /// Should we continue evaluation after encountering a side-effect that we
  /// couldn't model?
  bool keepEvaluatingAfterSideEffect() {
    switch (EvalMode) {
    case EM_IgnoreSideEffects:
      return true;

    case EM_ConstantExpression:
    case EM_ConstantExpressionUnevaluated:
    case EM_ConstantFold:
      // By default, assume any side effect might be valid in some other
      // evaluation of this expression from a different context.
      return checkingPotentialConstantExpression() ||
             checkingForUndefinedBehavior();
    }
    llvm_unreachable("Missed EvalMode case")__builtin_unreachable();
  }

  /// Note that we have had a side-effect, and determine whether we should
  /// keep evaluating.
  bool noteSideEffect() {
    EvalStatus.HasSideEffects = true;
    return keepEvaluatingAfterSideEffect();
  }

  /// Should we continue evaluation after encountering undefined behavior?
  bool keepEvaluatingAfterUndefinedBehavior() {
    switch (EvalMode) {
    case EM_IgnoreSideEffects:
    case EM_ConstantFold:
      return true;

    case EM_ConstantExpression:
    case EM_ConstantExpressionUnevaluated:
      return checkingForUndefinedBehavior();
    }
    llvm_unreachable("Missed EvalMode case")__builtin_unreachable();
  }

  /// Note that we hit something that was technically undefined behavior, but
  /// that we can evaluate past it (such as signed overflow or floating-point
  /// division by zero.)
  bool noteUndefinedBehavior() override {
    EvalStatus.HasUndefinedBehavior = true;
    return keepEvaluatingAfterUndefinedBehavior();
  }

  /// Should we continue evaluation as much as possible after encountering a
  /// construct which can't be reduced to a value?
  bool keepEvaluatingAfterFailure() const override {
    if (!StepsLeft)
      return false;

    switch (EvalMode) {
    case EM_ConstantExpression:
    case EM_ConstantExpressionUnevaluated:
    case EM_ConstantFold:
    case EM_IgnoreSideEffects:
      return checkingPotentialConstantExpression() ||
             checkingForUndefinedBehavior();
    }
    llvm_unreachable("Missed EvalMode case")__builtin_unreachable();
  }

  /// Notes that we failed to evaluate an expression that other expressions
  /// directly depend on, and determine if we should keep evaluating. This
  /// should only be called if we actually intend to keep evaluating.
  ///
  /// Call noteSideEffect() instead if we may be able to ignore the value that
  /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
  ///
  /// (Foo(), 1)      // use noteSideEffect
  /// (Foo() || true) // use noteSideEffect
  /// Foo() + 1       // use noteFailure
  LLVM_NODISCARD[[clang::warn_unused_result]] bool noteFailure() {
    // Failure when evaluating some expression often means there is some
    // subexpression whose evaluation was skipped. Therefore, (because we
    // don't track whether we skipped an expression when unwinding after an
    // evaluation failure) every evaluation failure that bubbles up from a
    // subexpression implies that a side-effect has potentially happened. We
    // skip setting the HasSideEffects flag to true until we decide to
    // continue evaluating after that point, which happens here.
    bool KeepGoing = keepEvaluatingAfterFailure();
    EvalStatus.HasSideEffects |= KeepGoing;
    return KeepGoing;
  }

  class ArrayInitLoopIndex {
    EvalInfo &Info;
    uint64_t OuterIndex;

  public:
    ArrayInitLoopIndex(EvalInfo &Info)
        : Info(Info), OuterIndex(Info.ArrayInitIndex) {
      Info.ArrayInitIndex = 0;
    }
    ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }

    operator uint64_t&() { return Info.ArrayInitIndex; }
  };
};

/// Object used to treat all foldable expressions as constant expressions.
struct FoldConstant {
  EvalInfo &Info;
  bool Enabled;
  bool HadNoPriorDiags;
  EvalInfo::EvaluationMode OldMode;

  explicit FoldConstant(EvalInfo &Info, bool Enabled)
    : Info(Info),
      Enabled(Enabled),
      HadNoPriorDiags(Info.EvalStatus.Diag &&
                      Info.EvalStatus.Diag->empty() &&
                      !Info.EvalStatus.HasSideEffects),
      OldMode(Info.EvalMode) {
    if (Enabled)
      Info.EvalMode = EvalInfo::EM_ConstantFold;
  }
  void keepDiagnostics() { Enabled = false; }
  ~FoldConstant() {
    if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
        !Info.EvalStatus.HasSideEffects)
      Info.EvalStatus.Diag->clear();
    Info.EvalMode = OldMode;
  }
};

/// RAII object used to set the current evaluation mode to ignore
/// side-effects.
struct IgnoreSideEffectsRAII {
  EvalInfo &Info;
  EvalInfo::EvaluationMode OldMode;
  explicit IgnoreSideEffectsRAII(EvalInfo &Info)
      : Info(Info), OldMode(Info.EvalMode) {
    Info.EvalMode = EvalInfo::EM_IgnoreSideEffects;
  }

  ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; }
};

/// RAII object used to optionally suppress diagnostics and side-effects from
/// a speculative evaluation.
class SpeculativeEvaluationRAII {
  EvalInfo *Info = nullptr;
  Expr::EvalStatus OldStatus;
  unsigned OldSpeculativeEvaluationDepth;

  void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
    Info = Other.Info;
    OldStatus = Other.OldStatus;
    OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth;
    Other.Info = nullptr;
  }

  void maybeRestoreState() {
    if (!Info)
      return;

    Info->EvalStatus = OldStatus;
    Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth;
  }

public:
  SpeculativeEvaluationRAII() = default;

  SpeculativeEvaluationRAII(
      EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
      : Info(&Info), OldStatus(Info.EvalStatus),
        OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) {
    Info.EvalStatus.Diag = NewDiag;
    Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1;
  }

  SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
  SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
    moveFromAndCancel(std::move(Other));
  }

  SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
    maybeRestoreState();
    moveFromAndCancel(std::move(Other));
    return *this;
  }

  ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
};

/// RAII object wrapping a full-expression or block scope, and handling
/// the ending of the lifetime of temporaries created within it.
template<ScopeKind Kind>
class ScopeRAII {
  EvalInfo &Info;
  unsigned OldStackSize;
public:
  ScopeRAII(EvalInfo &Info)
      : Info(Info), OldStackSize(Info.CleanupStack.size()) {
    // Push a new temporary version. This is needed to distinguish between
    // temporaries created in different iterations of a loop.
    Info.CurrentCall->pushTempVersion();
  }
  bool destroy(bool RunDestructors = true) {
    bool OK = cleanup(Info, RunDestructors, OldStackSize);
    OldStackSize = -1U;
    return OK;
  }
  ~ScopeRAII() {
    if (OldStackSize != -1U)
      destroy(false);
    // Body moved to a static method to encourage the compiler to inline away
    // instances of this class.
    Info.CurrentCall->popTempVersion();
  }
private:
  static bool cleanup(EvalInfo &Info, bool RunDestructors,
                      unsigned OldStackSize) {
    assert(OldStackSize <= Info.CleanupStack.size() &&((void)0)
           "running cleanups out of order?")((void)0);

    // Run all cleanups for a block scope, and non-lifetime-extended cleanups
    // for a full-expression scope.
    bool Success = true;
    for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) {
      if (Info.CleanupStack[I - 1].isDestroyedAtEndOf(Kind)) {
        if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) {
          Success = false;
          break;
        }
      }
    }

    // Compact any retained cleanups.
    auto NewEnd = Info.CleanupStack.begin() + OldStackSize;
    if (Kind != ScopeKind::Block)
      NewEnd =
          std::remove_if(NewEnd, Info.CleanupStack.end(), [](Cleanup &C) {
            return C.isDestroyedAtEndOf(Kind);
          });
    Info.CleanupStack.erase(NewEnd, Info.CleanupStack.end());
    return Success;
  }
};
typedef ScopeRAII<ScopeKind::Block> BlockScopeRAII;
typedef ScopeRAII<ScopeKind::FullExpression> FullExpressionRAII;
typedef ScopeRAII<ScopeKind::Call> CallScopeRAII;
1397}

1399bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
                                       CheckSubobjectKind CSK) {
if (Invalid)
  return false;
if (isOnePastTheEnd()) {
  Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
    << CSK;
  setInvalid();
  return false;
}
// Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there
// must actually be at least one array element; even a VLA cannot have a
// bound of zero. And if our index is nonzero, we already had a CCEDiag.
return true;
1413}

1415void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info,
                                                              const Expr *E) {
Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed);
// Do not set the designator as invalid: we can represent this situation,
// and correct handling of __builtin_object_size requires us to do so.
1420}

1422void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
                                                  const Expr *E,
                                                  const APSInt &N) {
// If we're complaining, we must be able to statically determine the size of
// the most derived array.
if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
  Info.CCEDiag(E, diag::note_constexpr_array_index)
    << N << /*array*/ 0
    << static_cast<unsigned>(getMostDerivedArraySize());
else
  Info.CCEDiag(E, diag::note_constexpr_array_index)
    << N << /*non-array*/ 1;
setInvalid();
1435}

1437CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
                             const FunctionDecl *Callee, const LValue *This,
                             CallRef Call)
  : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
    Arguments(Call), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
Info.CurrentCall = this;
++Info.CallStackDepth;
1444}

1446CallStackFrame::~CallStackFrame() {
assert(Info.CurrentCall == this && "calls retired out of order")((void)0);
--Info.CallStackDepth;
Info.CurrentCall = Caller;
1450}

1452static bool isRead(AccessKinds AK) {
return AK == AK_Read || AK == AK_ReadObjectRepresentation;
1454}

1456static bool isModification(AccessKinds AK) {
switch (AK) {
case AK_Read:
case AK_ReadObjectRepresentation:
case AK_MemberCall:
case AK_DynamicCast:
case AK_TypeId:
  return false;
case AK_Assign:
case AK_Increment:
case AK_Decrement:
case AK_Construct:
case AK_Destroy:
  return true;
}
llvm_unreachable("unknown access kind")__builtin_unreachable();
1472}

1474static bool isAnyAccess(AccessKinds AK) {
return isRead(AK) || isModification(AK);
1476}

1478/// Is this an access per the C++ definition?
1479static bool isFormalAccess(AccessKinds AK) {
return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy;
1481}

1483/// Is this kind of axcess valid on an indeterminate object value?
1484static bool isValidIndeterminateAccess(AccessKinds AK) {
switch (AK) {
case AK_Read:
case AK_Increment:
case AK_Decrement:
  // These need the object's value.
  return false;

case AK_ReadObjectRepresentation:
case AK_Assign:
case AK_Construct:
case AK_Destroy:
  // Construction and destruction don't need the value.
  return true;

case AK_MemberCall:
case AK_DynamicCast:
case AK_TypeId:
  // These aren't really meaningful on scalars.
  return true;
}
llvm_unreachable("unknown access kind")__builtin_unreachable();
1506}

1508namespace {
struct ComplexValue {
private:
  bool IsInt;

public:
  APSInt IntReal, IntImag;
  APFloat FloatReal, FloatImag;

  ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}

  void makeComplexFloat() { IsInt = false; }
  bool isComplexFloat() const { return !IsInt; }
  APFloat &getComplexFloatReal() { return FloatReal; }
  APFloat &getComplexFloatImag() { return FloatImag; }

  void makeComplexInt() { IsInt = true; }
  bool isComplexInt() const { return IsInt; }
  APSInt &getComplexIntReal() { return IntReal; }
  APSInt &getComplexIntImag() { return IntImag; }

  void moveInto(APValue &v) const {
    if (isComplexFloat())
      v = APValue(FloatReal, FloatImag);
    else
      v = APValue(IntReal, IntImag);
  }
  void setFrom(const APValue &v) {
    assert(v.isComplexFloat() || v.isComplexInt())((void)0);
    if (v.isComplexFloat()) {
      makeComplexFloat();
      FloatReal = v.getComplexFloatReal();
      FloatImag = v.getComplexFloatImag();
    } else {
      makeComplexInt();
      IntReal = v.getComplexIntReal();
      IntImag = v.getComplexIntImag();
    }
  }
};

struct LValue {
  APValue::LValueBase Base;
  CharUnits Offset;
  SubobjectDesignator Designator;
  bool IsNullPtr : 1;
  bool InvalidBase : 1;

  const APValue::LValueBase getLValueBase() const { return Base; }
  CharUnits &getLValueOffset() { return Offset; }
  const CharUnits &getLValueOffset() const { return Offset; }
  SubobjectDesignator &getLValueDesignator() { return Designator; }
  const SubobjectDesignator &getLValueDesignator() const { return Designator;}
  bool isNullPointer() const { return IsNullPtr;}

  unsigned getLValueCallIndex() const { return Base.getCallIndex(); }
  unsigned getLValueVersion() const { return Base.getVersion(); }

  void moveInto(APValue &V) const {
    if (Designator.Invalid)
      V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr);
    else {
      assert(!InvalidBase && "APValues can't handle invalid LValue bases")((void)0);
      V = APValue(Base, Offset, Designator.Entries,
                  Designator.IsOnePastTheEnd, IsNullPtr);
    }
  }
  void setFrom(ASTContext &Ctx, const APValue &V) {
    assert(V.isLValue() && "Setting LValue from a non-LValue?")((void)0);
    Base = V.getLValueBase();
    Offset = V.getLValueOffset();
    InvalidBase = false;
    Designator = SubobjectDesignator(Ctx, V);
    IsNullPtr = V.isNullPointer();
  }

  void set(APValue::LValueBase B, bool BInvalid = false) {
1585#ifndef NDEBUG1
    // We only allow a few types of invalid bases. Enforce that here.
    if (BInvalid) {
      const auto *E = B.get<const Expr *>();
      assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&((void)0)
             "Unexpected type of invalid base")((void)0);
    }
1592#endif

    Base = B;
    Offset = CharUnits::fromQuantity(0);
    InvalidBase = BInvalid;
    Designator = SubobjectDesignator(getType(B));
    IsNullPtr = false;
  }

  void setNull(ASTContext &Ctx, QualType PointerTy) {
    Base = (const ValueDecl *)nullptr;
    Offset =
        CharUnits::fromQuantity(Ctx.getTargetNullPointerValue(PointerTy));
    InvalidBase = false;
    Designator = SubobjectDesignator(PointerTy->getPointeeType());
    IsNullPtr = true;
  }

  void setInvalid(APValue::LValueBase B, unsigned I = 0) {
    set(B, true);
  }

  std::string toString(ASTContext &Ctx, QualType T) const {
    APValue Printable;
    moveInto(Printable);
    return Printable.getAsString(Ctx, T);
  }

private:
  // Check that this LValue is not based on a null pointer. If it is, produce
  // a diagnostic and mark the designator as invalid.
  template <typename GenDiagType>
  bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) {
    if (Designator.Invalid)
      return false;
    if (IsNullPtr) {
      GenDiag();
      Designator.setInvalid();
      return false;
    }
    return true;
  }

public:
  bool checkNullPointer(EvalInfo &Info, const Expr *E,
                        CheckSubobjectKind CSK) {
    return checkNullPointerDiagnosingWith([&Info, E, CSK] {
      Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK;
    });
  }

  bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E,
                                     AccessKinds AK) {
    return checkNullPointerDiagnosingWith([&Info, E, AK] {
      Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
    });
  }

  // Check this LValue refers to an object. If not, set the designator to be
  // invalid and emit a diagnostic.
  bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
    return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
           Designator.checkSubobject(Info, E, CSK);
  }

  void addDecl(EvalInfo &Info, const Expr *E,
               const Decl *D, bool Virtual = false) {
    if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
      Designator.addDeclUnchecked(D, Virtual);
  }
  void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) {
    if (!Designator.Entries.empty()) {
      Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array);
      Designator.setInvalid();
      return;
    }
    if (checkSubobject(Info, E, CSK_ArrayToPointer)) {
      assert(getType(Base)->isPointerType() || getType(Base)->isArrayType())((void)0);
      Designator.FirstEntryIsAnUnsizedArray = true;
      Designator.addUnsizedArrayUnchecked(ElemTy);
    }
  }
  void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
    if (checkSubobject(Info, E, CSK_ArrayToPointer))
      Designator.addArrayUnchecked(CAT);
  }
  void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
    if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
      Designator.addComplexUnchecked(EltTy, Imag);
  }
  void clearIsNullPointer() {
    IsNullPtr = false;
  }
  void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
                            const APSInt &Index, CharUnits ElementSize) {
    // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
    // but we're not required to diagnose it and it's valid in C++.)
    if (!Index)
      return;

    // Compute the new offset in the appropriate width, wrapping at 64 bits.
    // FIXME: When compiling for a 32-bit target, we should use 32-bit
    // offsets.
    uint64_t Offset64 = Offset.getQuantity();
    uint64_t ElemSize64 = ElementSize.getQuantity();
    uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
    Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64);

    if (checkNullPointer(Info, E, CSK_ArrayIndex))
      Designator.adjustIndex(Info, E, Index);
    clearIsNullPointer();
  }
  void adjustOffset(CharUnits N) {
    Offset += N;
    if (N.getQuantity())
      clearIsNullPointer();
  }
};

struct MemberPtr {
  MemberPtr() {}
  explicit MemberPtr(const ValueDecl *Decl) :
    DeclAndIsDerivedMember(Decl, false), Path() {}

  /// The member or (direct or indirect) field referred to by this member
  /// pointer, or 0 if this is a null member pointer.
  const ValueDecl *getDecl() const {
    return DeclAndIsDerivedMember.getPointer();
  }
  /// Is this actually a member of some type derived from the relevant class?
  bool isDerivedMember() const {
    return DeclAndIsDerivedMember.getInt();
  }
  /// Get the class which the declaration actually lives in.
  const CXXRecordDecl *getContainingRecord() const {
    return cast<CXXRecordDecl>(
        DeclAndIsDerivedMember.getPointer()->getDeclContext());
  }

  void moveInto(APValue &V) const {
    V = APValue(getDecl(), isDerivedMember(), Path);
  }
  void setFrom(const APValue &V) {
    assert(V.isMemberPointer())((void)0);
    DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
    DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
    Path.clear();
    ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
    Path.insert(Path.end(), P.begin(), P.end());
  }

  /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
  /// whether the member is a member of some class derived from the class type
  /// of the member pointer.
  llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
  /// Path - The path of base/derived classes from the member declaration's
  /// class (exclusive) to the class type of the member pointer (inclusive).
  SmallVector<const CXXRecordDecl*, 4> Path;

  /// Perform a cast towards the class of the Decl (either up or down the
  /// hierarchy).
  bool castBack(const CXXRecordDecl *Class) {
    assert(!Path.empty())((void)0);
    const CXXRecordDecl *Expected;
    if (Path.size() >= 2)
      Expected = Path[Path.size() - 2];
    else
      Expected = getContainingRecord();
    if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
      // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
      // if B does not contain the original member and is not a base or
      // derived class of the class containing the original member, the result
      // of the cast is undefined.
      // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
      // (D::*). We consider that to be a language defect.
      return false;
    }
    Path.pop_back();
    return true;
  }
  /// Perform a base-to-derived member pointer cast.
  bool castToDerived(const CXXRecordDecl *Derived) {
    if (!getDecl())
      return true;
    if (!isDerivedMember()) {
      Path.push_back(Derived);
      return true;
    }
    if (!castBack(Derived))
      return false;
    if (Path.empty())
      DeclAndIsDerivedMember.setInt(false);
    return true;
  }
  /// Perform a derived-to-base member pointer cast.
  bool castToBase(const CXXRecordDecl *Base) {
    if (!getDecl())
      return true;
    if (Path.empty())
      DeclAndIsDerivedMember.setInt(true);
    if (isDerivedMember()) {
      Path.push_back(Base);
      return true;
    }
    return castBack(Base);
  }
};

/// Compare two member pointers, which are assumed to be of the same type.
static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
  if (!LHS.getDecl() || !RHS.getDecl())
    return !LHS.getDecl() && !RHS.getDecl();
  if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
    return false;
  return LHS.Path == RHS.Path;
}
1808}

1810static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1811static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
                          const LValue &This, const Expr *E,
                          bool AllowNonLiteralTypes = false);
1814static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
                         bool InvalidBaseOK = false);
1816static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
                          bool InvalidBaseOK = false);
1818static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
                                EvalInfo &Info);
1820static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1821static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1822static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
                                  EvalInfo &Info);
1824static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1825static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1826static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
                         EvalInfo &Info);
1828static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);

1830/// Evaluate an integer or fixed point expression into an APResult.
1831static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
                                      EvalInfo &Info);

1834/// Evaluate only a fixed point expression into an APResult.
1835static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
                             EvalInfo &Info);

1838//===----------------------------------------------------------------------===//
1839// Misc utilities
1840//===----------------------------------------------------------------------===//

1842/// Negate an APSInt in place, converting it to a signed form if necessary, and
1843/// preserving its value (by extending by up to one bit as needed).
1844static void negateAsSigned(APSInt &Int) {
if (Int.isUnsigned() || Int.isMinSignedValue()) {
  Int = Int.extend(Int.getBitWidth() + 1);
  Int.setIsSigned(true);
}
Int = -Int;
1850}

1852template<typename KeyT>
1853APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T,
                                       ScopeKind Scope, LValue &LV) {
unsigned Version = getTempVersion();
APValue::LValueBase Base(Key, Index, Version);
LV.set(Base);
return createLocal(Base, Key, T, Scope);
1859}

1861/// Allocate storage for a parameter of a function call made in this frame.
1862APValue &CallStackFrame::createParam(CallRef Args, const ParmVarDecl *PVD,
                                   LValue &LV) {
assert(Args.CallIndex == Index && "creating parameter in wrong frame")((void)0);
APValue::LValueBase Base(PVD, Index, Args.Version);
LV.set(Base);
// We always destroy parameters at the end of the call, even if we'd allow
// them to live to the end of the full-expression at runtime, in order to
// give portable results and match other compilers.
return createLocal(Base, PVD, PVD->getType(), ScopeKind::Call);
1871}

1873APValue &CallStackFrame::createLocal(APValue::LValueBase Base, const void *Key,
                                   QualType T, ScopeKind Scope) {
assert(Base.getCallIndex() == Index && "lvalue for wrong frame")((void)0);
unsigned Version = Base.getVersion();
APValue &Result = Temporaries[MapKeyTy(Key, Version)];
assert(Result.isAbsent() && "local created multiple times")((void)0);

// If we're creating a local immediately in the operand of a speculative
// evaluation, don't register a cleanup to be run outside the speculative
// evaluation context, since we won't actually be able to initialize this
// object.
if (Index <= Info.SpeculativeEvaluationDepth) {
  if (T.isDestructedType())
    Info.noteSideEffect();
} else {
  Info.CleanupStack.push_back(Cleanup(&Result, Base, T, Scope));
}
return Result;
1891}

1893APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) {
if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) {
  FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded);
  return nullptr;
}

DynamicAllocLValue DA(NumHeapAllocs++);
LV.set(APValue::LValueBase::getDynamicAlloc(DA, T));
auto Result = HeapAllocs.emplace(std::piecewise_construct,
                                 std::forward_as_tuple(DA), std::tuple<>());
assert(Result.second && "reused a heap alloc index?")((void)0);
Result.first->second.AllocExpr = E;
return &Result.first->second.Value;
1906}

1908/// Produce a string describing the given constexpr call.
1909void CallStackFrame::describe(raw_ostream &Out) {
unsigned ArgIndex = 0;
bool IsMemberCall = isa<CXXMethodDecl>(Callee) &&
                    !isa<CXXConstructorDecl>(Callee) &&
                    cast<CXXMethodDecl>(Callee)->isInstance();

if (!IsMemberCall)
  Out << *Callee << '(';

if (This && IsMemberCall) {
  APValue Val;
  This->moveInto(Val);
  Val.printPretty(Out, Info.Ctx,
                  This->Designator.MostDerivedType);
  // FIXME: Add parens around Val if needed.
  Out << "->" << *Callee << '(';
  IsMemberCall = false;
}

for (FunctionDecl::param_const_iterator I = Callee->param_begin(),
     E = Callee->param_end(); I != E; ++I, ++ArgIndex) {
  if (ArgIndex > (unsigned)IsMemberCall)
    Out << ", ";

  const ParmVarDecl *Param = *I;
  APValue *V = Info.getParamSlot(Arguments, Param);
  if (V)
    V->printPretty(Out, Info.Ctx, Param->getType());
  else
    Out << "<...>";

  if (ArgIndex == 0 && IsMemberCall)
    Out << "->" << *Callee << '(';
}

Out << ')';
1945}

1947/// Evaluate an expression to see if it had side-effects, and discard its
1948/// result.
1949/// \return \c true if the caller should keep evaluating.
1950static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
assert(!E->isValueDependent())((void)0);
APValue Scratch;
if (!Evaluate(Scratch, Info, E))
  // We don't need the value, but we might have skipped a side effect here.
  return Info.noteSideEffect();
return true;
1957}

1959/// Should this call expression be treated as a string literal?
1960static bool IsStringLiteralCall(const CallExpr *E) {
unsigned Builtin = E->getBuiltinCallee();
return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
        Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1964}

1966static bool IsGlobalLValue(APValue::LValueBase B) {
// C++11 [expr.const]p3 An address constant expression is a prvalue core
// constant expression of pointer type that evaluates to...

// ... a null pointer value, or a prvalue core constant expression of type
// std::nullptr_t.
if (!B) return true;

if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
  // ... the address of an object with static storage duration,
  if (const VarDecl *VD = dyn_cast<VarDecl>(D))
    return VD->hasGlobalStorage();
  if (isa<TemplateParamObjectDecl>(D))
    return true;
  // ... the address of a function,
  // ... the address of a GUID [MS extension],
  return isa<FunctionDecl>(D) || isa<MSGuidDecl>(D);
}

if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>())
  return true;

const Expr *E = B.get<const Expr*>();
switch (E->getStmtClass()) {
default:
  return false;
case Expr::CompoundLiteralExprClass: {
  const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
  return CLE->isFileScope() && CLE->isLValue();
}
case Expr::MaterializeTemporaryExprClass:
  // A materialized temporary might have been lifetime-extended to static
  // storage duration.
  return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
// A string literal has static storage duration.
case Expr::StringLiteralClass:
case Expr::PredefinedExprClass:
case Expr::ObjCStringLiteralClass:
case Expr::ObjCEncodeExprClass:
  return true;
case Expr::ObjCBoxedExprClass:
  return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer();
case Expr::CallExprClass:
  return IsStringLiteralCall(cast<CallExpr>(E));
// For GCC compatibility, &&label has static storage duration.
case Expr::AddrLabelExprClass:
  return true;
// A Block literal expression may be used as the initialization value for
// Block variables at global or local static scope.
case Expr::BlockExprClass:
  return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
case Expr::ImplicitValueInitExprClass:
  // FIXME:
  // We can never form an lvalue with an implicit value initialization as its
  // base through expression evaluation, so these only appear in one case: the
  // implicit variable declaration we invent when checking whether a constexpr
  // constructor can produce a constant expression. We must assume that such
  // an expression might be a global lvalue.
  return true;
}
2026}

2028static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
return LVal.Base.dyn_cast<const ValueDecl*>();
2030}

2032static bool IsLiteralLValue(const LValue &Value) {
if (Value.getLValueCallIndex())
  return false;
const Expr *E = Value.Base.dyn_cast<const Expr*>();
return E && !isa<MaterializeTemporaryExpr>(E);
2037}

2039static bool IsWeakLValue(const LValue &Value) {
const ValueDecl *Decl = GetLValueBaseDecl(Value);
return Decl && Decl->isWeak();
2042}

2044static bool isZeroSized(const LValue &Value) {
const ValueDecl *Decl = GetLValueBaseDecl(Value);
if (Decl && isa<VarDecl>(Decl)) {
  QualType Ty = Decl->getType();
  if (Ty->isArrayType())
    return Ty->isIncompleteType() ||
           Decl->getASTContext().getTypeSize(Ty) == 0;
}
return false;
2053}

2055static bool HasSameBase(const LValue &A, const LValue &B) {
if (!A.getLValueBase())
  return !B.getLValueBase();
if (!B.getLValueBase())
  return false;

if (A.getLValueBase().getOpaqueValue() !=
    B.getLValueBase().getOpaqueValue())
  return false;

return A.getLValueCallIndex() == B.getLValueCallIndex() &&
       A.getLValueVersion() == B.getLValueVersion();
2067}

2069static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
assert(Base && "no location for a null lvalue")((void)0);
const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();

// For a parameter, find the corresponding call stack frame (if it still
// exists), and point at the parameter of the function definition we actually
// invoked.
if (auto *PVD = dyn_cast_or_null<ParmVarDecl>(VD)) {
  unsigned Idx = PVD->getFunctionScopeIndex();
  for (CallStackFrame *F = Info.CurrentCall; F; F = F->Caller) {
    if (F->Arguments.CallIndex == Base.getCallIndex() &&
        F->Arguments.Version == Base.getVersion() && F->Callee &&
        Idx < F->Callee->getNumParams()) {
      VD = F->Callee->getParamDecl(Idx);
      break;
    }
  }
}

if (VD)
  Info.Note(VD->getLocation(), diag::note_declared_at);
else if (const Expr *E = Base.dyn_cast<const Expr*>())
  Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here);
else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
  // FIXME: Produce a note for dangling pointers too.
  if (Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA))
    Info.Note((*Alloc)->AllocExpr->getExprLoc(),
              diag::note_constexpr_dynamic_alloc_here);
}
// We have no information to show for a typeid(T) object.
2099}

2101enum class CheckEvaluationResultKind {
ConstantExpression,
FullyInitialized,
2104};

2106/// Materialized temporaries that we've already checked to determine if they're
2107/// initializsed by a constant expression.
2108using CheckedTemporaries =
  llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>;

2111static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
                                EvalInfo &Info, SourceLocation DiagLoc,
                                QualType Type, const APValue &Value,
                                ConstantExprKind Kind,
                                SourceLocation SubobjectLoc,
                                CheckedTemporaries &CheckedTemps);

2118/// Check that this reference or pointer core constant expression is a valid
2119/// value for an address or reference constant expression. Return true if we
2120/// can fold this expression, whether or not it's a constant expression.
2121static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
                                        QualType Type, const LValue &LVal,
                                        ConstantExprKind Kind,
                                        CheckedTemporaries &CheckedTemps) {
bool IsReferenceType = Type->isReferenceType();

APValue::LValueBase Base = LVal.getLValueBase();
const SubobjectDesignator &Designator = LVal.getLValueDesignator();

const Expr *BaseE = Base.dyn_cast<const Expr *>();
const ValueDecl *BaseVD = Base.dyn_cast<const ValueDecl*>();

// Additional restrictions apply in a template argument. We only enforce the
// C++20 restrictions here; additional syntactic and semantic restrictions
// are applied elsewhere.
if (isTemplateArgument(Kind)) {
  int InvalidBaseKind = -1;
  StringRef Ident;
  if (Base.is<TypeInfoLValue>())
    InvalidBaseKind = 0;
  else if (isa_and_nonnull<StringLiteral>(BaseE))
    InvalidBaseKind = 1;
  else if (isa_and_nonnull<MaterializeTemporaryExpr>(BaseE) ||
           isa_and_nonnull<LifetimeExtendedTemporaryDecl>(BaseVD))
    InvalidBaseKind = 2;
  else if (auto *PE = dyn_cast_or_null<PredefinedExpr>(BaseE)) {
    InvalidBaseKind = 3;
    Ident = PE->getIdentKindName();
  }

  if (InvalidBaseKind != -1) {
    Info.FFDiag(Loc, diag::note_constexpr_invalid_template_arg)
        << IsReferenceType << !Designator.Entries.empty() << InvalidBaseKind
        << Ident;
    return false;
  }
}

if (auto *FD = dyn_cast_or_null<FunctionDecl>(BaseVD)) {
  if (FD->isConsteval()) {
    Info.FFDiag(Loc, diag::note_consteval_address_accessible)
        << !Type->isAnyPointerType();
    Info.Note(FD->getLocation(), diag::note_declared_at);
    return false;
  }
}

// Check that the object is a global. Note that the fake 'this' object we
// manufacture when checking potential constant expressions is conservatively
// assumed to be global here.
if (!IsGlobalLValue(Base)) {
  if (Info.getLangOpts().CPlusPlus11) {
    const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
    Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
      << IsReferenceType << !Designator.Entries.empty()
      << !!VD << VD;

    auto *VarD = dyn_cast_or_null<VarDecl>(VD);
    if (VarD && VarD->isConstexpr()) {
      // Non-static local constexpr variables have unintuitive semantics:
      //   constexpr int a = 1;
      //   constexpr const int *p = &a;
      // ... is invalid because the address of 'a' is not constant. Suggest
      // adding a 'static' in this case.
      Info.Note(VarD->getLocation(), diag::note_constexpr_not_static)
          << VarD
          << FixItHint::CreateInsertion(VarD->getBeginLoc(), "static ");
    } else {
      NoteLValueLocation(Info, Base);
    }
  } else {
    Info.FFDiag(Loc);
  }
  // Don't allow references to temporaries to escape.
  return false;
}
assert((Info.checkingPotentialConstantExpression() ||((void)0)
        LVal.getLValueCallIndex() == 0) &&((void)0)
       "have call index for global lvalue")((void)0);

if (Base.is<DynamicAllocLValue>()) {
  Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc)
      << IsReferenceType << !Designator.Entries.empty();
  NoteLValueLocation(Info, Base);
  return false;
}

if (BaseVD) {
  if (const VarDecl *Var = dyn_cast<const VarDecl>(BaseVD)) {
    // Check if this is a thread-local variable.
    if (Var->getTLSKind())
      // FIXME: Diagnostic!
      return false;

    // A dllimport variable never acts like a constant, unless we're
    // evaluating a value for use only in name mangling.
    if (!isForManglingOnly(Kind) && Var->hasAttr<DLLImportAttr>())
      // FIXME: Diagnostic!
      return false;
  }
  if (const auto *FD = dyn_cast<const FunctionDecl>(BaseVD)) {
    // __declspec(dllimport) must be handled very carefully:
    // We must never initialize an expression with the thunk in C++.
    // Doing otherwise would allow the same id-expression to yield
    // different addresses for the same function in different translation
    // units.  However, this means that we must dynamically initialize the
    // expression with the contents of the import address table at runtime.
    //
    // The C language has no notion of ODR; furthermore, it has no notion of
    // dynamic initialization.  This means that we are permitted to
    // perform initialization with the address of the thunk.
    if (Info.getLangOpts().CPlusPlus && !isForManglingOnly(Kind) &&
        FD->hasAttr<DLLImportAttr>())
      // FIXME: Diagnostic!
      return false;
  }
} else if (const auto *MTE =
               dyn_cast_or_null<MaterializeTemporaryExpr>(BaseE)) {
  if (CheckedTemps.insert(MTE).second) {
    QualType TempType = getType(Base);
    if (TempType.isDestructedType()) {
      Info.FFDiag(MTE->getExprLoc(),
                  diag::note_constexpr_unsupported_temporary_nontrivial_dtor)
          << TempType;
      return false;
    }

    APValue *V = MTE->getOrCreateValue(false);
    assert(V && "evasluation result refers to uninitialised temporary")((void)0);
    if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
                               Info, MTE->getExprLoc(), TempType, *V,
                               Kind, SourceLocation(), CheckedTemps))
      return false;
  }
}

// Allow address constant expressions to be past-the-end pointers. This is
// an extension: the standard requires them to point to an object.
if (!IsReferenceType)
  return true;

// A reference constant expression must refer to an object.
if (!Base) {
  // FIXME: diagnostic
  Info.CCEDiag(Loc);
  return true;
}

// Does this refer one past the end of some object?
if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
  Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
    << !Designator.Entries.empty() << !!BaseVD << BaseVD;
  NoteLValueLocation(Info, Base);
}

return true;
2277}

2279/// Member pointers are constant expressions unless they point to a
2280/// non-virtual dllimport member function.
2281static bool CheckMemberPointerConstantExpression(EvalInfo &Info,
                                               SourceLocation Loc,
                                               QualType Type,
                                               const APValue &Value,
                                               ConstantExprKind Kind) {
const ValueDecl *Member = Value.getMemberPointerDecl();
const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member);
if (!FD)
  return true;
if (FD->isConsteval()) {
  Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0;
  Info.Note(FD->getLocation(), diag::note_declared_at);
  return false;
}
return isForManglingOnly(Kind) || FD->isVirtual() ||
       !FD->hasAttr<DLLImportAttr>();
2297}

2299/// Check that this core constant expression is of literal type, and if not,
2300/// produce an appropriate diagnostic.
2301static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
                           const LValue *This = nullptr) {
if (!E->isPRValue() || E->getType()->isLiteralType(Info.Ctx))
  return true;

// C++1y: A constant initializer for an object o [...] may also invoke
// constexpr constructors for o and its subobjects even if those objects
// are of non-literal class types.
//
// C++11 missed this detail for aggregates, so classes like this:
//   struct foo_t { union { int i; volatile int j; } u; };
// are not (obviously) initializable like so:
//   __attribute__((__require_constant_initialization__))
//   static const foo_t x = {{0}};
// because "i" is a subobject with non-literal initialization (due to the
// volatile member of the union). See:
//   http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
// Therefore, we use the C++1y behavior.
if (This && Info.EvaluatingDecl == This->getLValueBase())
  return true;

// Prvalue constant expressions must be of literal types.
if (Info.getLangOpts().CPlusPlus11)
  Info.FFDiag(E, diag::note_constexpr_nonliteral)
    << E->getType();
else
  Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
return false;
2329}

2331static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
                                EvalInfo &Info, SourceLocation DiagLoc,
                                QualType Type, const APValue &Value,
                                ConstantExprKind Kind,
                                SourceLocation SubobjectLoc,
                                CheckedTemporaries &CheckedTemps) {
if (!Value.hasValue()) {
  Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
    << true << Type;
  if (SubobjectLoc.isValid())
    Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here);
  return false;
}

// We allow _Atomic(T) to be initialized from anything that T can be
// initialized from.
if (const AtomicType *AT = Type->getAs<AtomicType>())
  Type = AT->getValueType();

// Core issue 1454: For a literal constant expression of array or class type,
// each subobject of its value shall have been initialized by a constant
// expression.
if (Value.isArray()) {
  QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
  for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
    if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
                               Value.getArrayInitializedElt(I), Kind,
                               SubobjectLoc, CheckedTemps))
      return false;
  }
  if (!Value.hasArrayFiller())
    return true;
  return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
                               Value.getArrayFiller(), Kind, SubobjectLoc,
                               CheckedTemps);
}
if (Value.isUnion() && Value.getUnionField()) {
  return CheckEvaluationResult(
      CERK, Info, DiagLoc, Value.getUnionField()->getType(),
      Value.getUnionValue(), Kind, Value.getUnionField()->getLocation(),
      CheckedTemps);
}
if (Value.isStruct()) {
  RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
  if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
    unsigned BaseIndex = 0;
    for (const CXXBaseSpecifier &BS : CD->bases()) {
      if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(),
                                 Value.getStructBase(BaseIndex), Kind,
                                 BS.getBeginLoc(), CheckedTemps))
        return false;
      ++BaseIndex;
    }
  }
  for (const auto *I : RD->fields()) {
    if (I->isUnnamedBitfield())
      continue;

    if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(),
                               Value.getStructField(I->getFieldIndex()),
                               Kind, I->getLocation(), CheckedTemps))
      return false;
  }
}

if (Value.isLValue() &&
    CERK == CheckEvaluationResultKind::ConstantExpression) {
  LValue LVal;
  LVal.setFrom(Info.Ctx, Value);
  return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Kind,
                                       CheckedTemps);
}

if (Value.isMemberPointer() &&
    CERK == CheckEvaluationResultKind::ConstantExpression)
  return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Kind);

// Everything else is fine.
return true;
2410}

2412/// Check that this core constant expression value is a valid value for a
2413/// constant expression. If not, report an appropriate diagnostic. Does not
2414/// check that the expression is of literal type.
2415static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
                                  QualType Type, const APValue &Value,
                                  ConstantExprKind Kind) {
// Nothing to check for a constant expression of type 'cv void'.
if (Type->isVoidType())
  return true;

CheckedTemporaries CheckedTemps;
return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
                             Info, DiagLoc, Type, Value, Kind,
                             SourceLocation(), CheckedTemps);
2426}

2428/// Check that this evaluated value is fully-initialized and can be loaded by
2429/// an lvalue-to-rvalue conversion.
2430static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc,
                                QualType Type, const APValue &Value) {
CheckedTemporaries CheckedTemps;
return CheckEvaluationResult(
    CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value,
    ConstantExprKind::Normal, SourceLocation(), CheckedTemps);
2436}

2438/// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless
2439/// "the allocated storage is deallocated within the evaluation".
2440static bool CheckMemoryLeaks(EvalInfo &Info) {
if (!Info.HeapAllocs.empty()) {
  // We can still fold to a constant despite a compile-time memory leak,
  // so long as the heap allocation isn't referenced in the result (we check
  // that in CheckConstantExpression).
  Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr,
               diag::note_constexpr_memory_leak)
      << unsigned(Info.HeapAllocs.size() - 1);
}
return true;
2450}

2452static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
// A null base expression indicates a null pointer.  These are always
// evaluatable, and they are false unless the offset is zero.
if (!Value.getLValueBase()) {
  Result = !Value.getLValueOffset().isZero();
  return true;
}

// We have a non-null base.  These are generally known to be true, but if it's
// a weak declaration it can be null at runtime.
Result = true;
const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
return !Decl || !Decl->isWeak();
2465}

2467static bool HandleConversionToBool(const APValue &Val, bool &Result) {
switch (Val.getKind()) {
case APValue::None:
case APValue::Indeterminate:
  return false;
case APValue::Int:
  Result = Val.getInt().getBoolValue();
  return true;
case APValue::FixedPoint:
  Result = Val.getFixedPoint().getBoolValue();
  return true;
case APValue::Float:
  Result = !Val.getFloat().isZero();
  return true;
case APValue::ComplexInt:
  Result = Val.getComplexIntReal().getBoolValue() ||
           Val.getComplexIntImag().getBoolValue();
  return true;
case APValue::ComplexFloat:
  Result = !Val.getComplexFloatReal().isZero() ||
           !Val.getComplexFloatImag().isZero();
  return true;
case APValue::LValue:
  return EvalPointerValueAsBool(Val, Result);
case APValue::MemberPointer:
  Result = Val.getMemberPointerDecl();
  return true;
case APValue::Vector:
case APValue::Array:
case APValue::Struct:
case APValue::Union:
case APValue::AddrLabelDiff:
  return false;
}

llvm_unreachable("unknown APValue kind")__builtin_unreachable();
2503}

2505static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
                                     EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && "missing lvalue-to-rvalue conv in bool condition")((void)0);
APValue Val;
if (!Evaluate(Val, Info, E))
  return false;
return HandleConversionToBool(Val, Result);
2513}

2515template<typename T>
2516static bool HandleOverflow(EvalInfo &Info, const Expr *E,
                         const T &SrcValue, QualType DestType) {
Info.CCEDiag(E, diag::note_constexpr_overflow)
  << SrcValue << DestType;
return Info.noteUndefinedBehavior();
2521}

2523static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
                               QualType SrcType, const APFloat &Value,
                               QualType DestType, APSInt &Result) {
unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
// Determine whether we are converting to unsigned or signed.
bool DestSigned = DestType->isSignedIntegerOrEnumerationType();

Result = APSInt(DestWidth, !DestSigned);
bool ignored;
if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
    & APFloat::opInvalidOp)
  return HandleOverflow(Info, E, Value, DestType);
return true;
2536}

2538/// Get rounding mode used for evaluation of the specified expression.
2539/// \param[out] DynamicRM Is set to true is the requested rounding mode is
2540///                       dynamic.
2541/// If rounding mode is unknown at compile time, still try to evaluate the
2542/// expression. If the result is exact, it does not depend on rounding mode.
2543/// So return "tonearest" mode instead of "dynamic".
2544static llvm::RoundingMode getActiveRoundingMode(EvalInfo &Info, const Expr *E,
                                              bool &DynamicRM) {
llvm::RoundingMode RM =
    E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).getRoundingMode();
DynamicRM = (RM == llvm::RoundingMode::Dynamic);
if (DynamicRM)
  RM = llvm::RoundingMode::NearestTiesToEven;
return RM;
2552}

2554/// Check if the given evaluation result is allowed for constant evaluation.
2555static bool checkFloatingPointResult(EvalInfo &Info, const Expr *E,
                                   APFloat::opStatus St) {
// In a constant context, assume that any dynamic rounding mode or FP
// exception state matches the default floating-point environment.
if (Info.InConstantContext)
  return true;

FPOptions FPO = E->getFPFeaturesInEffect(Info.Ctx.getLangOpts());
if ((St & APFloat::opInexact) &&
    FPO.getRoundingMode() == llvm::RoundingMode::Dynamic) {
  // Inexact result means that it depends on rounding mode. If the requested
  // mode is dynamic, the evaluation cannot be made in compile time.
  Info.FFDiag(E, diag::note_constexpr_dynamic_rounding);
  return false;
}

if ((St != APFloat::opOK) &&
    (FPO.getRoundingMode() == llvm::RoundingMode::Dynamic ||
     FPO.getFPExceptionMode() != LangOptions::FPE_Ignore ||
     FPO.getAllowFEnvAccess())) {
  Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
  return false;
}

if ((St & APFloat::opStatus::opInvalidOp) &&
    FPO.getFPExceptionMode() != LangOptions::FPE_Ignore) {
  // There is no usefully definable result.
  Info.FFDiag(E);
  return false;
}

// FIXME: if:
// - evaluation triggered other FP exception, and
// - exception mode is not "ignore", and
// - the expression being evaluated is not a part of global variable
//   initializer,
// the evaluation probably need to be rejected.
return true;
2593}

2595static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
                                 QualType SrcType, QualType DestType,
                                 APFloat &Result) {
assert(isa<CastExpr>(E) || isa<CompoundAssignOperator>(E))((void)0);
bool DynamicRM;
llvm::RoundingMode RM = getActiveRoundingMode(Info, E, DynamicRM);
APFloat::opStatus St;
APFloat Value = Result;
bool ignored;
St = Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), RM, &ignored);
return checkFloatingPointResult(Info, E, St);
2606}

2608static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
                               QualType DestType, QualType SrcType,
                               const APSInt &Value) {
unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
// Figure out if this is a truncate, extend or noop cast.
// If the input is signed, do a sign extend, noop, or truncate.
APSInt Result = Value.extOrTrunc(DestWidth);
Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
if (DestType->isBooleanType())
  Result = Value.getBoolValue();
return Result;
2619}

2621static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
                               const FPOptions FPO,
                               QualType SrcType, const APSInt &Value,
                               QualType DestType, APFloat &Result) {
Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
APFloat::opStatus St = Result.convertFromAPInt(Value, Value.isSigned(),
     APFloat::rmNearestTiesToEven);
if (!Info.InConstantContext && St != llvm::APFloatBase::opOK &&
    FPO.isFPConstrained()) {
  Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
  return false;
}
return true;
2634}

2636static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
                                APValue &Value, const FieldDecl *FD) {
assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield")((void)0);

if (!Value.isInt()) {
  // Trying to store a pointer-cast-to-integer into a bitfield.
  // FIXME: In this case, we should provide the diagnostic for casting
  // a pointer to an integer.
  assert(Value.isLValue() && "integral value neither int nor lvalue?")((void)0);
  Info.FFDiag(E);
  return false;
}

APSInt &Int = Value.getInt();
unsigned OldBitWidth = Int.getBitWidth();
unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
if (NewBitWidth < OldBitWidth)
  Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
return true;
2655}

2657static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
                                llvm::APInt &Res) {
APValue SVal;
if (!Evaluate(SVal, Info, E))
  return false;
if (SVal.isInt()) {
  Res = SVal.getInt();
  return true;
}
if (SVal.isFloat()) {
  Res = SVal.getFloat().bitcastToAPInt();
  return true;
}
if (SVal.isVector()) {
  QualType VecTy = E->getType();
  unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
  QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
  unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
  bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
  Res = llvm::APInt::getNullValue(VecSize);
  for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
    APValue &Elt = SVal.getVectorElt(i);
    llvm::APInt EltAsInt;
    if (Elt.isInt()) {
      EltAsInt = Elt.getInt();
    } else if (Elt.isFloat()) {
      EltAsInt = Elt.getFloat().bitcastToAPInt();
    } else {
      // Don't try to handle vectors of anything other than int or float
      // (not sure if it's possible to hit this case).
      Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
      return false;
    }
    unsigned BaseEltSize = EltAsInt.getBitWidth();
    if (BigEndian)
      Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
    else
      Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
  }
  return true;
}
// Give up if the input isn't an int, float, or vector.  For example, we
// reject "(v4i16)(intptr_t)&a".
Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
return false;
2702}

2704/// Perform the given integer operation, which is known to need at most BitWidth
2705/// bits, and check for overflow in the original type (if that type was not an
2706/// unsigned type).
2707template<typename Operation>
2708static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
                               const APSInt &LHS, const APSInt &RHS,
                               unsigned BitWidth, Operation Op,
                               APSInt &Result) {
if (LHS.isUnsigned()) {
  Result = Op(LHS, RHS);
  return true;
}

APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
Result = Value.trunc(LHS.getBitWidth());
if (Result.extend(BitWidth) != Value) {
  if (Info.checkingForUndefinedBehavior())
    Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
                                     diag::warn_integer_constant_overflow)
        << toString(Result, 10) << E->getType();
  return HandleOverflow(Info, E, Value, E->getType());
}
return true;
2727}

2729/// Perform the given binary integer operation.
2730static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
                            BinaryOperatorKind Opcode, APSInt RHS,
                            APSInt &Result) {
switch (Opcode) {
default:
  Info.FFDiag(E);
  return false;
case BO_Mul:
  return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
                              std::multiplies<APSInt>(), Result);
case BO_Add:
  return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
                              std::plus<APSInt>(), Result);
case BO_Sub:
  return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
                              std::minus<APSInt>(), Result);
case BO_And: Result = LHS & RHS; return true;
case BO_Xor: Result = LHS ^ RHS; return true;
case BO_Or:  Result = LHS | RHS; return true;
case BO_Div:
case BO_Rem:
  if (RHS == 0) {
    Info.FFDiag(E, diag::note_expr_divide_by_zero);
    return false;
  }
  Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
  // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
  // this operation and gives the two's complement result.
  if (RHS.isNegative() && RHS.isAllOnesValue() &&
      LHS.isSigned() && LHS.isMinSignedValue())
    return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
                          E->getType());
  return true;
case BO_Shl: {
  if (Info.getLangOpts().OpenCL)
    // OpenCL 6.3j: shift values are effectively % word size of LHS.
    RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
                  static_cast<uint64_t>(LHS.getBitWidth() - 1)),
                  RHS.isUnsigned());
  else if (RHS.isSigned() && RHS.isNegative()) {
    // During constant-folding, a negative shift is an opposite shift. Such
    // a shift is not a constant expression.
    Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
    RHS = -RHS;
    goto shift_right;
  }
shift_left:
  // C++11 [expr.shift]p1: Shift width must be less than the bit width of
  // the shifted type.
  unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
  if (SA != RHS) {
    Info.CCEDiag(E, diag::note_constexpr_large_shift)
      << RHS << E->getType() << LHS.getBitWidth();
  } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) {
    // C++11 [expr.shift]p2: A signed left shift must have a non-negative
    // operand, and must not overflow the corresponding unsigned type.
    // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to
    // E1 x 2^E2 module 2^N.
    if (LHS.isNegative())
      Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
    else if (LHS.countLeadingZeros() < SA)
      Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
  }
  Result = LHS << SA;
  return true;
}
case BO_Shr: {
  if (Info.getLangOpts().OpenCL)
    // OpenCL 6.3j: shift values are effectively % word size of LHS.
    RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
                  static_cast<uint64_t>(LHS.getBitWidth() - 1)),
                  RHS.isUnsigned());
  else if (RHS.isSigned() && RHS.isNegative()) {
    // During constant-folding, a negative shift is an opposite shift. Such a
    // shift is not a constant expression.
    Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
    RHS = -RHS;
    goto shift_left;
  }
shift_right:
  // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
  // shifted type.
  unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
  if (SA != RHS)
    Info.CCEDiag(E, diag::note_constexpr_large_shift)
      << RHS << E->getType() << LHS.getBitWidth();
  Result = LHS >> SA;
  return true;
}

case BO_LT: Result = LHS < RHS; return true;
case BO_GT: Result = LHS > RHS; return true;
case BO_LE: Result = LHS <= RHS; return true;
case BO_GE: Result = LHS >= RHS; return true;
case BO_EQ: Result = LHS == RHS; return true;
case BO_NE: Result = LHS != RHS; return true;
case BO_Cmp:
  llvm_unreachable("BO_Cmp should be handled elsewhere")__builtin_unreachable();
}
2829}

2831/// Perform the given binary floating-point operation, in-place, on LHS.
2832static bool handleFloatFloatBinOp(EvalInfo &Info, const BinaryOperator *E,
                                APFloat &LHS, BinaryOperatorKind Opcode,
                                const APFloat &RHS) {
bool DynamicRM;
llvm::RoundingMode RM = getActiveRoundingMode(Info, E, DynamicRM);
APFloat::opStatus St;
switch (Opcode) {
default:
  Info.FFDiag(E);
  return false;
case BO_Mul:
  St = LHS.multiply(RHS, RM);
  break;
case BO_Add:
  St = LHS.add(RHS, RM);
  break;
case BO_Sub:
  St = LHS.subtract(RHS, RM);
  break;
case BO_Div:
  // [expr.mul]p4:
  //   If the second operand of / or % is zero the behavior is undefined.
  if (RHS.isZero())
    Info.CCEDiag(E, diag::note_expr_divide_by_zero);
  St = LHS.divide(RHS, RM);
  break;
}

// [expr.pre]p4:
//   If during the evaluation of an expression, the result is not
//   mathematically defined [...], the behavior is undefined.
// FIXME: C++ rules require us to not conform to IEEE 754 here.
if (LHS.isNaN()) {
  Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
  return Info.noteUndefinedBehavior();
}

return checkFloatingPointResult(Info, E, St);
2870}

2872static bool handleLogicalOpForVector(const APInt &LHSValue,
                                   BinaryOperatorKind Opcode,
                                   const APInt &RHSValue, APInt &Result) {
bool LHS = (LHSValue != 0);
bool RHS = (RHSValue != 0);

if (Opcode == BO_LAnd)
  Result = LHS && RHS;
else
  Result = LHS || RHS;
return true;
2883}
2884static bool handleLogicalOpForVector(const APFloat &LHSValue,
                                   BinaryOperatorKind Opcode,
                                   const APFloat &RHSValue, APInt &Result) {
bool LHS = !LHSValue.isZero();
bool RHS = !RHSValue.isZero();

if (Opcode == BO_LAnd)
  Result = LHS && RHS;
else
  Result = LHS || RHS;
return true;
2895}

2897static bool handleLogicalOpForVector(const APValue &LHSValue,
                                   BinaryOperatorKind Opcode,
                                   const APValue &RHSValue, APInt &Result) {
// The result is always an int type, however operands match the first.
if (LHSValue.getKind() == APValue::Int)
  return handleLogicalOpForVector(LHSValue.getInt(), Opcode,
                                  RHSValue.getInt(), Result);
assert(LHSValue.getKind() == APValue::Float && "Should be no other options")((void)0);
return handleLogicalOpForVector(LHSValue.getFloat(), Opcode,
                                RHSValue.getFloat(), Result);
2907}

2909template <typename APTy>
2910static bool
2911handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode,
                             const APTy &RHSValue, APInt &Result) {
switch (Opcode) {
default:
  llvm_unreachable("unsupported binary operator")__builtin_unreachable();
case BO_EQ:
  Result = (LHSValue == RHSValue);
  break;
case BO_NE:
  Result = (LHSValue != RHSValue);
  break;
case BO_LT:
  Result = (LHSValue < RHSValue);
  break;
case BO_GT:
  Result = (LHSValue > RHSValue);
  break;
case BO_LE:
  Result = (LHSValue <= RHSValue);
  break;
case BO_GE:
  Result = (LHSValue >= RHSValue);
  break;
}

return true;
2937}

2939static bool handleCompareOpForVector(const APValue &LHSValue,
                                   BinaryOperatorKind Opcode,
                                   const APValue &RHSValue, APInt &Result) {
// The result is always an int type, however operands match the first.
if (LHSValue.getKind() == APValue::Int)
  return handleCompareOpForVectorHelper(LHSValue.getInt(), Opcode,
                                        RHSValue.getInt(), Result);
assert(LHSValue.getKind() == APValue::Float && "Should be no other options")((void)0);
return handleCompareOpForVectorHelper(LHSValue.getFloat(), Opcode,
                                      RHSValue.getFloat(), Result);
2949}

2951// Perform binary operations for vector types, in place on the LHS.
2952static bool handleVectorVectorBinOp(EvalInfo &Info, const BinaryOperator *E,
                                  BinaryOperatorKind Opcode,
                                  APValue &LHSValue,
                                  const APValue &RHSValue) {
assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI &&((void)0)
       "Operation not supported on vector types")((void)0);

const auto *VT = E->getType()->castAs<VectorType>();
unsigned NumElements = VT->getNumElements();
QualType EltTy = VT->getElementType();

// In the cases (typically C as I've observed) where we aren't evaluating
// constexpr but are checking for cases where the LHS isn't yet evaluatable,
// just give up.
if (!LHSValue.isVector()) {
  assert(LHSValue.isLValue() &&((void)0)
         "A vector result that isn't a vector OR uncalculated LValue")((void)0);
  Info.FFDiag(E);
  return false;
}

assert(LHSValue.getVectorLength() == NumElements &&((void)0)
       RHSValue.getVectorLength() == NumElements && "Different vector sizes")((void)0);

SmallVector<APValue, 4> ResultElements;

for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) {
  APValue LHSElt = LHSValue.getVectorElt(EltNum);
  APValue RHSElt = RHSValue.getVectorElt(EltNum);

  if (EltTy->isIntegerType()) {
    APSInt EltResult{Info.Ctx.getIntWidth(EltTy),
                     EltTy->isUnsignedIntegerType()};
    bool Success = true;

    if (BinaryOperator::isLogicalOp(Opcode))
      Success = handleLogicalOpForVector(LHSElt, Opcode, RHSElt, EltResult);
    else if (BinaryOperator::isComparisonOp(Opcode))
      Success = handleCompareOpForVector(LHSElt, Opcode, RHSElt, EltResult);
    else
      Success = handleIntIntBinOp(Info, E, LHSElt.getInt(), Opcode,
                                  RHSElt.getInt(), EltResult);

    if (!Success) {
      Info.FFDiag(E);
      return false;
    }
    ResultElements.emplace_back(EltResult);

  } else if (EltTy->isFloatingType()) {
    assert(LHSElt.getKind() == APValue::Float &&((void)0)
           RHSElt.getKind() == APValue::Float &&((void)0)
           "Mismatched LHS/RHS/Result Type")((void)0);
    APFloat LHSFloat = LHSElt.getFloat();

    if (!handleFloatFloatBinOp(Info, E, LHSFloat, Opcode,
                               RHSElt.getFloat())) {
      Info.FFDiag(E);
      return false;
    }

    ResultElements.emplace_back(LHSFloat);
  }
}

LHSValue = APValue(ResultElements.data(), ResultElements.size());
return true;
3019}

3021/// Cast an lvalue referring to a base subobject to a derived class, by
3022/// truncating the lvalue's path to the given length.
3023static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
                             const RecordDecl *TruncatedType,
                             unsigned TruncatedElements) {
SubobjectDesignator &D = Result.Designator;

// Check we actually point to a derived class object.
if (TruncatedElements == D.Entries.size())
  return true;
assert(TruncatedElements >= D.MostDerivedPathLength &&((void)0)
       "not casting to a derived class")((void)0);
if (!Result.checkSubobject(Info, E, CSK_Derived))
  return false;

// Truncate the path to the subobject, and remove any derived-to-base offsets.
const RecordDecl *RD = TruncatedType;
for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
  if (RD->isInvalidDecl()) return false;
  const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
  const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
  if (isVirtualBaseClass(D.Entries[I]))
    Result.Offset -= Layout.getVBaseClassOffset(Base);
  else
    Result.Offset -= Layout.getBaseClassOffset(Base);
  RD = Base;
}
D.Entries.resize(TruncatedElements);
return true;
3050}

3052static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
                                 const CXXRecordDecl *Derived,
                                 const CXXRecordDecl *Base,
                                 const ASTRecordLayout *RL = nullptr) {
if (!RL) {
  if (Derived->isInvalidDecl()) return false;
  RL = &Info.Ctx.getASTRecordLayout(Derived);
}

Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
Obj.addDecl(Info, E, Base, /*Virtual*/ false);
return true;
3064}

3066static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
                           const CXXRecordDecl *DerivedDecl,
                           const CXXBaseSpecifier *Base) {
const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();

if (!Base->isVirtual())
  return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);

SubobjectDesignator &D = Obj.Designator;
if (D.Invalid)
  return false;

// Extract most-derived object and corresponding type.
DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
  return false;

// Find the virtual base class.
if (DerivedDecl->isInvalidDecl()) return false;
const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
return true;
3089}

3091static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
                               QualType Type, LValue &Result) {
for (CastExpr::path_const_iterator PathI = E->path_begin(),
                                   PathE = E->path_end();
     PathI != PathE; ++PathI) {
  if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
                        *PathI))
    return false;
  Type = (*PathI)->getType();
}
return true;
3102}

3104/// Cast an lvalue referring to a derived class to a known base subobject.
3105static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result,
                          const CXXRecordDecl *DerivedRD,
                          const CXXRecordDecl *BaseRD) {
CXXBasePaths Paths(/*FindAmbiguities=*/false,
                   /*RecordPaths=*/true, /*DetectVirtual=*/false);
if (!DerivedRD->isDerivedFrom(BaseRD, Paths))
  llvm_unreachable("Class must be derived from the passed in base class!")__builtin_unreachable();

for (CXXBasePathElement &Elem : Paths.front())
  if (!HandleLValueBase(Info, E, Result, Elem.Class, Elem.Base))
    return false;
return true;
3117}

3119/// Update LVal to refer to the given field, which must be a member of the type
3120/// currently described by LVal.
3121static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
                             const FieldDecl *FD,
                             const ASTRecordLayout *RL = nullptr) {
if (!RL) {
  if (FD->getParent()->isInvalidDecl()) return false;
  RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
}

unsigned I = FD->getFieldIndex();
LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
LVal.addDecl(Info, E, FD);
return true;
3133}

3135/// Update LVal to refer to the given indirect field.
3136static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
                                     LValue &LVal,
                                     const IndirectFieldDecl *IFD) {
for (const auto *C : IFD->chain())
  if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
    return false;
return true;
3143}

3145/// Get the size of the given type in char units.
3146static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
                       QualType Type, CharUnits &Size) {
// sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
// extension.
if (Type->isVoidType() || Type->isFunctionType()) {
  Size = CharUnits::One();
  return true;
}

if (Type->isDependentType()) {
  Info.FFDiag(Loc);
  return false;
}

if (!Type->isConstantSizeType()) {
  // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
  // FIXME: Better diagnostic.
  Info.FFDiag(Loc);
  return false;
}

Size = Info.Ctx.getTypeSizeInChars(Type);
return true;
3169}

3171/// Update a pointer value to model pointer arithmetic.
3172/// \param Info - Information about the ongoing evaluation.
3173/// \param E - The expression being evaluated, for diagnostic purposes.
3174/// \param LVal - The pointer value to be updated.
3175/// \param EltTy - The pointee type represented by LVal.
3176/// \param Adjustment - The adjustment, in objects of type EltTy, to add.
3177static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
                                      LValue &LVal, QualType EltTy,
                                      APSInt Adjustment) {
CharUnits SizeOfPointee;
if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
  return false;

LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
return true;
3186}

3188static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
                                      LValue &LVal, QualType EltTy,
                                      int64_t Adjustment) {
return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
                                   APSInt::get(Adjustment));
3193}

3195/// Update an lvalue to refer to a component of a complex number.
3196/// \param Info - Information about the ongoing evaluation.
3197/// \param LVal - The lvalue to be updated.
3198/// \param EltTy - The complex number's component type.
3199/// \param Imag - False for the real component, true for the imaginary.
3200static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
                                     LValue &LVal, QualType EltTy,
                                     bool Imag) {
if (Imag) {
  CharUnits SizeOfComponent;
  if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
    return false;
  LVal.Offset += SizeOfComponent;
}
LVal.addComplex(Info, E, EltTy, Imag);
return true;
3211}

3213/// Try to evaluate the initializer for a variable declaration.
3214///
3215/// \param Info   Information about the ongoing evaluation.
3216/// \param E      An expression to be used when printing diagnostics.
3217/// \param VD     The variable whose initializer should be obtained.
3218/// \param Version The version of the variable within the frame.
3219/// \param Frame  The frame in which the variable was created. Must be null
3220///               if this variable is not local to the evaluation.
3221/// \param Result Filled in with a pointer to the value of the variable.
3222static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
                              const VarDecl *VD, CallStackFrame *Frame,
                              unsigned Version, APValue *&Result) {
APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version);

// If this is a local variable, dig out its value.
if (Frame) {
  Result = Frame->getTemporary(VD, Version);
  if (Result)
    return true;

  if (!isa<ParmVarDecl>(VD)) {
    // Assume variables referenced within a lambda's call operator that were
    // not declared within the call operator are captures and during checking
    // of a potential constant expression, assume they are unknown constant
    // expressions.
    assert(isLambdaCallOperator(Frame->Callee) &&((void)0)
           (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&((void)0)
           "missing value for local variable")((void)0);
    if (Info.checkingPotentialConstantExpression())
      return false;
    // FIXME: This diagnostic is bogus; we do support captures. Is this code
    // still reachable at all?
    Info.FFDiag(E->getBeginLoc(),
                diag::note_unimplemented_constexpr_lambda_feature_ast)
        << "captures not currently allowed";
    return false;
  }
}

// If we're currently evaluating the initializer of this declaration, use that
// in-flight value.
if (Info.EvaluatingDecl == Base) {
  Result = Info.EvaluatingDeclValue;
  return true;
}

if (isa<ParmVarDecl>(VD)) {
  // Assume parameters of a potential constant expression are usable in
  // constant expressions.
  if (!Info.checkingPotentialConstantExpression() ||
      !Info.CurrentCall->Callee ||
      !Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
    if (Info.getLangOpts().CPlusPlus11) {
      Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown)
          << VD;
      NoteLValueLocation(Info, Base);
    } else {
      Info.FFDiag(E);
    }
  }
  return false;
}

// Dig out the initializer, and use the declaration which it's attached to.
// FIXME: We should eventually check whether the variable has a reachable
// initializing declaration.
const Expr *Init = VD->getAnyInitializer(VD);
if (!Init) {
  // Don't diagnose during potential constant expression checking; an
  // initializer might be added later.
  if (!Info.checkingPotentialConstantExpression()) {
    Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1)
      << VD;
    NoteLValueLocation(Info, Base);
  }
  return false;
}

if (Init->isValueDependent()) {
  // The DeclRefExpr is not value-dependent, but the variable it refers to
  // has a value-dependent initializer. This should only happen in
  // constant-folding cases, where the variable is not actually of a suitable
  // type for use in a constant expression (otherwise the DeclRefExpr would
  // have been value-dependent too), so diagnose that.
  assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx))((void)0);
  if (!Info.checkingPotentialConstantExpression()) {
    Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
                       ? diag::note_constexpr_ltor_non_constexpr
                       : diag::note_constexpr_ltor_non_integral, 1)
        << VD << VD->getType();
    NoteLValueLocation(Info, Base);
  }
  return false;
}

// Check that we can fold the initializer. In C++, we will have already done
// this in the cases where it matters for conformance.
if (!VD->evaluateValue()) {
  Info.FFDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
  NoteLValueLocation(Info, Base);
  return false;
}

// Check that the variable is actually usable in constant expressions. For a
// const integral variable or a reference, we might have a non-constant
// initializer that we can nonetheless evaluate the initializer for. Such
// variables are not usable in constant expressions. In C++98, the
// initializer also syntactically needs to be an ICE.
//
// FIXME: We don't diagnose cases that aren't potentially usable in constant
// expressions here; doing so would regress diagnostics for things like
// reading from a volatile constexpr variable.
if ((Info.getLangOpts().CPlusPlus && !VD->hasConstantInitialization() &&
     VD->mightBeUsableInConstantExpressions(Info.Ctx)) ||
    ((Info.getLangOpts().CPlusPlus || Info.getLangOpts().OpenCL) &&
     !Info.getLangOpts().CPlusPlus11 && !VD->hasICEInitializer(Info.Ctx))) {
  Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
  NoteLValueLocation(Info, Base);
}

// Never use the initializer of a weak variable, not even for constant
// folding. We can't be sure that this is the definition that will be used.
if (VD->isWeak()) {
  Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD;
  NoteLValueLocation(Info, Base);
  return false;
}

Result = VD->getEvaluatedValue();
return true;
3343}

3345/// Get the base index of the given base class within an APValue representing
3346/// the given derived class.
3347static unsigned getBaseIndex(const CXXRecordDecl *Derived,
                           const CXXRecordDecl *Base) {
Base = Base->getCanonicalDecl();
unsigned Index = 0;
for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
       E = Derived->bases_end(); I != E; ++I, ++Index) {
  if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
    return Index;
}

llvm_unreachable("base class missing from derived class's bases list")__builtin_unreachable();
3358}

3360/// Extract the value of a character from a string literal.
3361static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
                                          uint64_t Index) {
assert(!isa<SourceLocExpr>(Lit) &&((void)0)
       "SourceLocExpr should have already been converted to a StringLiteral")((void)0);

// FIXME: Support MakeStringConstant
if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) {
  std::string Str;
  Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str);
  assert(Index <= Str.size() && "Index too large")((void)0);
  return APSInt::getUnsigned(Str.c_str()[Index]);
}

if (auto PE = dyn_cast<PredefinedExpr>(Lit))
  Lit = PE->getFunctionName();
const StringLiteral *S = cast<StringLiteral>(Lit);
const ConstantArrayType *CAT =
    Info.Ctx.getAsConstantArrayType(S->getType());
assert(CAT && "string literal isn't an array")((void)0);
QualType CharType = CAT->getElementType();
assert(CharType->isIntegerType() && "unexpected character type")((void)0);

APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
             CharType->isUnsignedIntegerType());
if (Index < S->getLength())
  Value = S->getCodeUnit(Index);
return Value;
3388}

3390// Expand a string literal into an array of characters.
3391//
3392// FIXME: This is inefficient; we should probably introduce something similar
3393// to the LLVM ConstantDataArray to make this cheaper.
3394static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S,
                              APValue &Result,
                              QualType AllocType = QualType()) {
const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
    AllocType.isNull() ? S->getType() : AllocType);
assert(CAT && "string literal isn't an array")((void)0);
QualType CharType = CAT->getElementType();
assert(CharType->isIntegerType() && "unexpected character type")((void)0);

unsigned Elts = CAT->getSize().getZExtValue();
Result = APValue(APValue::UninitArray(),
                 std::min(S->getLength(), Elts), Elts);
APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
             CharType->isUnsignedIntegerType());
if (Result.hasArrayFiller())
  Result.getArrayFiller() = APValue(Value);
for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
  Value = S->getCodeUnit(I);
  Result.getArrayInitializedElt(I) = APValue(Value);
}
3414}

3416// Expand an array so that it has more than Index filled elements.
3417static void expandArray(APValue &Array, unsigned Index) {
unsigned Size = Array.getArraySize();
assert(Index < Size)((void)0);

// Always at least double the number of elements for which we store a value.
unsigned OldElts = Array.getArrayInitializedElts();
unsigned NewElts = std::max(Index+1, OldElts * 2);
NewElts = std::min(Size, std::max(NewElts, 8u));

// Copy the data across.
APValue NewValue(APValue::UninitArray(), NewElts, Size);
for (unsigned I = 0; I != OldElts; ++I)
  NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
for (unsigned I = OldElts; I != NewElts; ++I)
  NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
if (NewValue.hasArrayFiller())
  NewValue.getArrayFiller() = Array.getArrayFiller();
Array.swap(NewValue);
3435}

3437/// Determine whether a type would actually be read by an lvalue-to-rvalue
3438/// conversion. If it's of class type, we may assume that the copy operation
3439/// is trivial. Note that this is never true for a union type with fields
3440/// (because the copy always "reads" the active member) and always true for
3441/// a non-class type.
3442static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD);
3443static bool isReadByLvalueToRvalueConversion(QualType T) {
CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
return !RD || isReadByLvalueToRvalueConversion(RD);
3446}
3447static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) {
// FIXME: A trivial copy of a union copies the object representation, even if
// the union is empty.
if (RD->isUnion())
38
←
Calling 'TagDecl::isUnion'→
41
←
Returning from 'TagDecl::isUnion'→
42
←
Taking true branch→
  return !RD->field_empty();
43
←
Calling 'RecordDecl::field_empty'→
52
←
Returning from 'RecordDecl::field_empty'→
53
←
Returning the value 1, which participates in a condition later→
if (RD->isEmpty())
  return false;

for (auto *Field : RD->fields())
  if (!Field->isUnnamedBitfield() &&
      isReadByLvalueToRvalueConversion(Field->getType()))
    return true;

for (auto &BaseSpec : RD->bases())
  if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
    return true;

return false;
3465}

3467/// Diagnose an attempt to read from any unreadable field within the specified
3468/// type, which might be a class type.
3469static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK,
                                QualType T) {
CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
if (!RD)
  return false;

if (!RD->hasMutableFields())
  return false;

for (auto *Field : RD->fields()) {
  // If we're actually going to read this field in some way, then it can't
  // be mutable. If we're in a union, then assigning to a mutable field
  // (even an empty one) can change the active member, so that's not OK.
  // FIXME: Add core issue number for the union case.
  if (Field->isMutable() &&
      (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
    Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field;
    Info.Note(Field->getLocation(), diag::note_declared_at);
    return true;
  }

  if (diagnoseMutableFields(Info, E, AK, Field->getType()))
    return true;
}

for (auto &BaseSpec : RD->bases())
  if (diagnoseMutableFields(Info, E, AK, BaseSpec.getType()))
    return true;

// All mutable fields were empty, and thus not actually read.
return false;
3500}

3502static bool lifetimeStartedInEvaluation(EvalInfo &Info,
                                      APValue::LValueBase Base,
                                      bool MutableSubobject = false) {
// A temporary or transient heap allocation we created.
if (Base.getCallIndex() || Base.is<DynamicAllocLValue>())
  return true;

switch (Info.IsEvaluatingDecl) {
case EvalInfo::EvaluatingDeclKind::None:
  return false;

case EvalInfo::EvaluatingDeclKind::Ctor:
  // The variable whose initializer we're evaluating.
  if (Info.EvaluatingDecl == Base)
    return true;

  // A temporary lifetime-extended by the variable whose initializer we're
  // evaluating.
  if (auto *BaseE = Base.dyn_cast<const Expr *>())
    if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(BaseE))
      return Info.EvaluatingDecl == BaseMTE->getExtendingDecl();
  return false;

case EvalInfo::EvaluatingDeclKind::Dtor:
  // C++2a [expr.const]p6:
  //   [during constant destruction] the lifetime of a and its non-mutable
  //   subobjects (but not its mutable subobjects) [are] considered to start
  //   within e.
  if (MutableSubobject || Base != Info.EvaluatingDecl)
    return false;
  // FIXME: We can meaningfully extend this to cover non-const objects, but
  // we will need special handling: we should be able to access only
  // subobjects of such objects that are themselves declared const.
  QualType T = getType(Base);
  return T.isConstQualified() || T->isReferenceType();
}

llvm_unreachable("unknown evaluating decl kind")__builtin_unreachable();
3540}

3542namespace {
3543/// A handle to a complete object (an object that is not a subobject of
3544/// another object).
3545struct CompleteObject {
/// The identity of the object.
APValue::LValueBase Base;
/// The value of the complete object.
APValue *Value;
/// The type of the complete object.
QualType Type;

CompleteObject() : Value(nullptr) {}
CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type)
    : Base(Base), Value(Value), Type(Type) {}

bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const {
  // If this isn't a "real" access (eg, if it's just accessing the type
  // info), allow it. We assume the type doesn't change dynamically for
  // subobjects of constexpr objects (even though we'd hit UB here if it
  // did). FIXME: Is this right?
  if (!isAnyAccess(AK))
    return true;

  // In C++14 onwards, it is permitted to read a mutable member whose
  // lifetime began within the evaluation.
  // FIXME: Should we also allow this in C++11?
  if (!Info.getLangOpts().CPlusPlus14)
    return false;
  return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true);
}

explicit operator bool() const { return !Type.isNull(); }
3574};
3575} // end anonymous namespace

3577static QualType getSubobjectType(QualType ObjType, QualType SubobjType,
                               bool IsMutable = false) {
// C++ [basic.type.qualifier]p1:
// - A const object is an object of type const T or a non-mutable subobject
//   of a const object.
if (ObjType.isConstQualified() && !IsMutable)
  SubobjType.addConst();
// - A volatile object is an object of type const T or a subobject of a
//   volatile object.
if (ObjType.isVolatileQualified())
  SubobjType.addVolatile();
return SubobjType;
3589}

3591/// Find the designated sub-object of an rvalue.
3592template<typename SubobjectHandler>
3593typename SubobjectHandler::result_type
3594findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
            const SubobjectDesignator &Sub, SubobjectHandler &handler) {
if (Sub.Invalid)
  // A diagnostic will have already been produced.
  return handler.failed();
if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) {
  if (Info.getLangOpts().CPlusPlus11)
    Info.FFDiag(E, Sub.isOnePastTheEnd()
                       ? diag::note_constexpr_access_past_end
                       : diag::note_constexpr_access_unsized_array)
        << handler.AccessKind;
  else
    Info.FFDiag(E);
  return handler.failed();
}

APValue *O = Obj.Value;
QualType ObjType = Obj.Type;
const FieldDecl *LastField = nullptr;
const FieldDecl *VolatileField = nullptr;

// Walk the designator's path to find the subobject.
for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
  // Reading an indeterminate value is undefined, but assigning over one is OK.
  if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) ||
      (O->isIndeterminate() &&
       !isValidIndeterminateAccess(handler.AccessKind))) {
    if (!Info.checkingPotentialConstantExpression())
      Info.FFDiag(E, diag::note_constexpr_access_uninit)
          << handler.AccessKind << O->isIndeterminate();
    return handler.failed();
  }

  // C++ [class.ctor]p5, C++ [class.dtor]p5:
  //    const and volatile semantics are not applied on an object under
  //    {con,de}struction.
  if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) &&
      ObjType->isRecordType() &&
      Info.isEvaluatingCtorDtor(
          Obj.Base, llvm::makeArrayRef(Sub.Entries.begin(),
                                       Sub.Entries.begin() + I)) !=
                        ConstructionPhase::None) {
    ObjType = Info.Ctx.getCanonicalType(ObjType);
    ObjType.removeLocalConst();
    ObjType.removeLocalVolatile();
  }

  // If this is our last pass, check that the final object type is OK.
  if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) {
    // Accesses to volatile objects are prohibited.
    if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) {
      if (Info.getLangOpts().CPlusPlus) {
        int DiagKind;
        SourceLocation Loc;
        const NamedDecl *Decl = nullptr;
        if (VolatileField) {
          DiagKind = 2;
          Loc = VolatileField->getLocation();
          Decl = VolatileField;
        } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) {
          DiagKind = 1;
          Loc = VD->getLocation();
          Decl = VD;
        } else {
          DiagKind = 0;
          if (auto *E = Obj.Base.dyn_cast<const Expr *>())
            Loc = E->getExprLoc();
        }
        Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
            << handler.AccessKind << DiagKind << Decl;
        Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind;
      } else {
        Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
      }
      return handler.failed();
    }

    // If we are reading an object of class type, there may still be more
    // things we need to check: if there are any mutable subobjects, we
    // cannot perform this read. (This only happens when performing a trivial
    // copy or assignment.)
    if (ObjType->isRecordType() &&
        !Obj.mayAccessMutableMembers(Info, handler.AccessKind) &&
        diagnoseMutableFields(Info, E, handler.AccessKind, ObjType))
      return handler.failed();
  }

  if (I == N) {
    if (!handler.found(*O, ObjType))
      return false;

    // If we modified a bit-field, truncate it to the right width.
    if (isModification(handler.AccessKind) &&
        LastField && LastField->isBitField() &&
        !truncateBitfieldValue(Info, E, *O, LastField))
      return false;

    return true;
  }

  LastField = nullptr;
  if (ObjType->isArrayType()) {
    // Next subobject is an array element.
    const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
    assert(CAT && "vla in literal type?")((void)0);
    uint64_t Index = Sub.Entries[I].getAsArrayIndex();
    if (CAT->getSize().ule(Index)) {
      // Note, it should not be possible to form a pointer with a valid
      // designator which points more than one past the end of the array.
      if (Info.getLangOpts().CPlusPlus11)
        Info.FFDiag(E, diag::note_constexpr_access_past_end)
          << handler.AccessKind;
      else
        Info.FFDiag(E);
      return handler.failed();
    }

    ObjType = CAT->getElementType();

    if (O->getArrayInitializedElts() > Index)
      O = &O->getArrayInitializedElt(Index);
    else if (!isRead(handler.AccessKind)) {
      expandArray(*O, Index);
      O = &O->getArrayInitializedElt(Index);
    } else
      O = &O->getArrayFiller();
  } else if (ObjType->isAnyComplexType()) {
    // Next subobject is a complex number.
    uint64_t Index = Sub.Entries[I].getAsArrayIndex();
    if (Index > 1) {
      if (Info.getLangOpts().CPlusPlus11)
        Info.FFDiag(E, diag::note_constexpr_access_past_end)
          << handler.AccessKind;
      else
        Info.FFDiag(E);
      return handler.failed();
    }

    ObjType = getSubobjectType(
        ObjType, ObjType->castAs<ComplexType>()->getElementType());

    assert(I == N - 1 && "extracting subobject of scalar?")((void)0);
    if (O->isComplexInt()) {
      return handler.found(Index ? O->getComplexIntImag()
                                 : O->getComplexIntReal(), ObjType);
    } else {
      assert(O->isComplexFloat())((void)0);
      return handler.found(Index ? O->getComplexFloatImag()
                                 : O->getComplexFloatReal(), ObjType);
    }
  } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
    if (Field->isMutable() &&
        !Obj.mayAccessMutableMembers(Info, handler.AccessKind)) {
      Info.FFDiag(E, diag::note_constexpr_access_mutable, 1)
        << handler.AccessKind << Field;
      Info.Note(Field->getLocation(), diag::note_declared_at);
      return handler.failed();
    }

    // Next subobject is a class, struct or union field.
    RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
    if (RD->isUnion()) {
      const FieldDecl *UnionField = O->getUnionField();
      if (!UnionField ||
          UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
        if (I == N - 1 && handler.AccessKind == AK_Construct) {
          // Placement new onto an inactive union member makes it active.
          O->setUnion(Field, APValue());
        } else {
          // FIXME: If O->getUnionValue() is absent, report that there's no
          // active union member rather than reporting the prior active union
          // member. We'll need to fix nullptr_t to not use APValue() as its
          // representation first.
          Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
              << handler.AccessKind << Field << !UnionField << UnionField;
          return handler.failed();
        }
      }
      O = &O->getUnionValue();
    } else
      O = &O->getStructField(Field->getFieldIndex());

    ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable());
    LastField = Field;
    if (Field->getType().isVolatileQualified())
      VolatileField = Field;
  } else {
    // Next subobject is a base class.
    const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
    const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
    O = &O->getStructBase(getBaseIndex(Derived, Base));

    ObjType = getSubobjectType(ObjType, Info.Ctx.getRecordType(Base));
  }
}
3789}

3791namespace {
3792struct ExtractSubobjectHandler {
EvalInfo &Info;
const Expr *E;
APValue &Result;
const AccessKinds AccessKind;

typedef bool result_type;
bool failed() { return false; }
bool found(APValue &Subobj, QualType SubobjType) {
  Result = Subobj;
  if (AccessKind == AK_ReadObjectRepresentation)
    return true;
  return CheckFullyInitialized(Info, E->getExprLoc(), SubobjType, Result);
}
bool found(APSInt &Value, QualType SubobjType) {
  Result = APValue(Value);
  return true;
}
bool found(APFloat &Value, QualType SubobjType) {
  Result = APValue(Value);
  return true;
}
3814};
3815} // end anonymous namespace

3817/// Extract the designated sub-object of an rvalue.
3818static bool extractSubobject(EvalInfo &Info, const Expr *E,
                           const CompleteObject &Obj,
                           const SubobjectDesignator &Sub, APValue &Result,
                           AccessKinds AK = AK_Read) {
assert(AK == AK_Read || AK == AK_ReadObjectRepresentation)((void)0);
ExtractSubobjectHandler Handler = {Info, E, Result, AK};
return findSubobject(Info, E, Obj, Sub, Handler);
3825}

3827namespace {
3828struct ModifySubobjectHandler {
EvalInfo &Info;
APValue &NewVal;
const Expr *E;

typedef bool result_type;
static const AccessKinds AccessKind = AK_Assign;

bool checkConst(QualType QT) {
  // Assigning to a const object has undefined behavior.
  if (QT.isConstQualified()) {
    Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
    return false;
  }
  return true;
}

bool failed() { return false; }
bool found(APValue &Subobj, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;
  // We've been given ownership of NewVal, so just swap it in.
  Subobj.swap(NewVal);
  return true;
}
bool found(APSInt &Value, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;
  if (!NewVal.isInt()) {
    // Maybe trying to write a cast pointer value into a complex?
    Info.FFDiag(E);
    return false;
  }
  Value = NewVal.getInt();
  return true;
}
bool found(APFloat &Value, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;
  Value = NewVal.getFloat();
  return true;
}
3870};
3871} // end anonymous namespace

3873const AccessKinds ModifySubobjectHandler::AccessKind;

3875/// Update the designated sub-object of an rvalue to the given value.
3876static bool modifySubobject(EvalInfo &Info, const Expr *E,
                          const CompleteObject &Obj,
                          const SubobjectDesignator &Sub,
                          APValue &NewVal) {
ModifySubobjectHandler Handler = { Info, NewVal, E };
return findSubobject(Info, E, Obj, Sub, Handler);
3882}

3884/// Find the position where two subobject designators diverge, or equivalently
3885/// the length of the common initial subsequence.
3886static unsigned FindDesignatorMismatch(QualType ObjType,
                                     const SubobjectDesignator &A,
                                     const SubobjectDesignator &B,
                                     bool &WasArrayIndex) {
unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
for (/**/; I != N; ++I) {
  if (!ObjType.isNull() &&
      (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
    // Next subobject is an array element.
    if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) {
      WasArrayIndex = true;
      return I;
    }
    if (ObjType->isAnyComplexType())
      ObjType = ObjType->castAs<ComplexType>()->getElementType();
    else
      ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
  } else {
    if (A.Entries[I].getAsBaseOrMember() !=
        B.Entries[I].getAsBaseOrMember()) {
      WasArrayIndex = false;
      return I;
    }
    if (const FieldDecl *FD = getAsField(A.Entries[I]))
      // Next subobject is a field.
      ObjType = FD->getType();
    else
      // Next subobject is a base class.
      ObjType = QualType();
  }
}
WasArrayIndex = false;
return I;
3919}

3921/// Determine whether the given subobject designators refer to elements of the
3922/// same array object.
3923static bool AreElementsOfSameArray(QualType ObjType,
                                 const SubobjectDesignator &A,
                                 const SubobjectDesignator &B) {
if (A.Entries.size() != B.Entries.size())
  return false;

bool IsArray = A.MostDerivedIsArrayElement;
if (IsArray && A.MostDerivedPathLength != A.Entries.size())
  // A is a subobject of the array element.
  return false;

// If A (and B) designates an array element, the last entry will be the array
// index. That doesn't have to match. Otherwise, we're in the 'implicit array
// of length 1' case, and the entire path must match.
bool WasArrayIndex;
unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
return CommonLength >= A.Entries.size() - IsArray;
3940}

3942/// Find the complete object to which an LValue refers.
3943static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
                                       AccessKinds AK, const LValue &LVal,
                                       QualType LValType) {
if (LVal.InvalidBase) {
  Info.FFDiag(E);
  return CompleteObject();
}

if (!LVal.Base) {
  Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
  return CompleteObject();
}

CallStackFrame *Frame = nullptr;
unsigned Depth = 0;
if (LVal.getLValueCallIndex()) {
  std::tie(Frame, Depth) =
      Info.getCallFrameAndDepth(LVal.getLValueCallIndex());
  if (!Frame) {
    Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
      << AK << LVal.Base.is<const ValueDecl*>();
    NoteLValueLocation(Info, LVal.Base);
    return CompleteObject();
  }
}

bool IsAccess = isAnyAccess(AK);

// C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
// is not a constant expression (even if the object is non-volatile). We also
// apply this rule to C++98, in order to conform to the expected 'volatile'
// semantics.
if (isFormalAccess(AK) && LValType.isVolatileQualified()) {
  if (Info.getLangOpts().CPlusPlus)
    Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
      << AK << LValType;
  else
    Info.FFDiag(E);
  return CompleteObject();
}

// Compute value storage location and type of base object.
APValue *BaseVal = nullptr;
QualType BaseType = getType(LVal.Base);

if (Info.getLangOpts().CPlusPlus14 && LVal.Base == Info.EvaluatingDecl &&
    lifetimeStartedInEvaluation(Info, LVal.Base)) {
  // This is the object whose initializer we're evaluating, so its lifetime
  // started in the current evaluation.
  BaseVal = Info.EvaluatingDeclValue;
} else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) {
  // Allow reading from a GUID declaration.
  if (auto *GD = dyn_cast<MSGuidDecl>(D)) {
    if (isModification(AK)) {
      // All the remaining cases do not permit modification of the object.
      Info.FFDiag(E, diag::note_constexpr_modify_global);
      return CompleteObject();
    }
    APValue &V = GD->getAsAPValue();
    if (V.isAbsent()) {
      Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
          << GD->getType();
      return CompleteObject();
    }
    return CompleteObject(LVal.Base, &V, GD->getType());
  }

  // Allow reading from template parameter objects.
  if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(D)) {
    if (isModification(AK)) {
      Info.FFDiag(E, diag::note_constexpr_modify_global);
      return CompleteObject();
    }
    return CompleteObject(LVal.Base, const_cast<APValue *>(&TPO->getValue()),
                          TPO->getType());
  }

  // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
  // In C++11, constexpr, non-volatile variables initialized with constant
  // expressions are constant expressions too. Inside constexpr functions,
  // parameters are constant expressions even if they're non-const.
  // In C++1y, objects local to a constant expression (those with a Frame) are
  // both readable and writable inside constant expressions.
  // In C, such things can also be folded, although they are not ICEs.
  const VarDecl *VD = dyn_cast<VarDecl>(D);
  if (VD) {
    if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
      VD = VDef;
  }
  if (!VD || VD->isInvalidDecl()) {
    Info.FFDiag(E);
    return CompleteObject();
  }

  bool IsConstant = BaseType.isConstant(Info.Ctx);

  // Unless we're looking at a local variable or argument in a constexpr call,
  // the variable we're reading must be const.
  if (!Frame) {
    if (IsAccess && isa<ParmVarDecl>(VD)) {
      // Access of a parameter that's not associated with a frame isn't going
      // to work out, but we can leave it to evaluateVarDeclInit to provide a
      // suitable diagnostic.
    } else if (Info.getLangOpts().CPlusPlus14 &&
               lifetimeStartedInEvaluation(Info, LVal.Base)) {
      // OK, we can read and modify an object if we're in the process of
      // evaluating its initializer, because its lifetime began in this
      // evaluation.
    } else if (isModification(AK)) {
      // All the remaining cases do not permit modification of the object.
      Info.FFDiag(E, diag::note_constexpr_modify_global);
      return CompleteObject();
    } else if (VD->isConstexpr()) {
      // OK, we can read this variable.
    } else if (BaseType->isIntegralOrEnumerationType()) {
      if (!IsConstant) {
        if (!IsAccess)
          return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
        if (Info.getLangOpts().CPlusPlus) {
          Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
          Info.Note(VD->getLocation(), diag::note_declared_at);
        } else {
          Info.FFDiag(E);
        }
        return CompleteObject();
      }
    } else if (!IsAccess) {
      return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
    } else if (IsConstant && Info.checkingPotentialConstantExpression() &&
               BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) {
      // This variable might end up being constexpr. Don't diagnose it yet.
    } else if (IsConstant) {
      // Keep evaluating to see what we can do. In particular, we support
      // folding of const floating-point types, in order to make static const
      // data members of such types (supported as an extension) more useful.
      if (Info.getLangOpts().CPlusPlus) {
        Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11
                            ? diag::note_constexpr_ltor_non_constexpr
                            : diag::note_constexpr_ltor_non_integral, 1)
            << VD << BaseType;
        Info.Note(VD->getLocation(), diag::note_declared_at);
      } else {
        Info.CCEDiag(E);
      }
    } else {
      // Never allow reading a non-const value.
      if (Info.getLangOpts().CPlusPlus) {
        Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
                           ? diag::note_constexpr_ltor_non_constexpr
                           : diag::note_constexpr_ltor_non_integral, 1)
            << VD << BaseType;
        Info.Note(VD->getLocation(), diag::note_declared_at);
      } else {
        Info.FFDiag(E);
      }
      return CompleteObject();
    }
  }

  if (!evaluateVarDeclInit(Info, E, VD, Frame, LVal.getLValueVersion(), BaseVal))
    return CompleteObject();
} else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) {
  Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA);
  if (!Alloc) {
    Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK;
    return CompleteObject();
  }
  return CompleteObject(LVal.Base, &(*Alloc)->Value,
                        LVal.Base.getDynamicAllocType());
} else {
  const Expr *Base = LVal.Base.dyn_cast<const Expr*>();

  if (!Frame) {
    if (const MaterializeTemporaryExpr *MTE =
            dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) {
      assert(MTE->getStorageDuration() == SD_Static &&((void)0)
             "should have a frame for a non-global materialized temporary")((void)0);

      // C++20 [expr.const]p4: [DR2126]
      //   An object or reference is usable in constant expressions if it is
      //   - a temporary object of non-volatile const-qualified literal type
      //     whose lifetime is extended to that of a variable that is usable
      //     in constant expressions
      //
      // C++20 [expr.const]p5:
      //  an lvalue-to-rvalue conversion [is not allowed unless it applies to]
      //   - a non-volatile glvalue that refers to an object that is usable
      //     in constant expressions, or
      //   - a non-volatile glvalue of literal type that refers to a
      //     non-volatile object whose lifetime began within the evaluation
      //     of E;
      //
      // C++11 misses the 'began within the evaluation of e' check and
      // instead allows all temporaries, including things like:
      //   int &&r = 1;
      //   int x = ++r;
      //   constexpr int k = r;
      // Therefore we use the C++14-onwards rules in C++11 too.
      //
      // Note that temporaries whose lifetimes began while evaluating a
      // variable's constructor are not usable while evaluating the
      // corresponding destructor, not even if they're of const-qualified
      // types.
      if (!MTE->isUsableInConstantExpressions(Info.Ctx) &&
          !lifetimeStartedInEvaluation(Info, LVal.Base)) {
        if (!IsAccess)
          return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
        Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
        Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
        return CompleteObject();
      }

      BaseVal = MTE->getOrCreateValue(false);
      assert(BaseVal && "got reference to unevaluated temporary")((void)0);
    } else {
      if (!IsAccess)
        return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
      APValue Val;
      LVal.moveInto(Val);
      Info.FFDiag(E, diag::note_constexpr_access_unreadable_object)
          << AK
          << Val.getAsString(Info.Ctx,
                             Info.Ctx.getLValueReferenceType(LValType));
      NoteLValueLocation(Info, LVal.Base);
      return CompleteObject();
    }
  } else {
    BaseVal = Frame->getTemporary(Base, LVal.Base.getVersion());
    assert(BaseVal && "missing value for temporary")((void)0);
  }
}

// In C++14, we can't safely access any mutable state when we might be
// evaluating after an unmodeled side effect. Parameters are modeled as state
// in the caller, but aren't visible once the call returns, so they can be
// modified in a speculatively-evaluated call.
//
// FIXME: Not all local state is mutable. Allow local constant subobjects
// to be read here (but take care with 'mutable' fields).
unsigned VisibleDepth = Depth;
if (llvm::isa_and_nonnull<ParmVarDecl>(
        LVal.Base.dyn_cast<const ValueDecl *>()))
  ++VisibleDepth;
if ((Frame && Info.getLangOpts().CPlusPlus14 &&
     Info.EvalStatus.HasSideEffects) ||
    (isModification(AK) && VisibleDepth < Info.SpeculativeEvaluationDepth))
  return CompleteObject();

return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType);
4192}

4194/// Perform an lvalue-to-rvalue conversion on the given glvalue. This
4195/// can also be used for 'lvalue-to-lvalue' conversions for looking up the
4196/// glvalue referred to by an entity of reference type.
4197///
4198/// \param Info - Information about the ongoing evaluation.
4199/// \param Conv - The expression for which we are performing the conversion.
4200///               Used for diagnostics.
4201/// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
4202///               case of a non-class type).
4203/// \param LVal - The glvalue on which we are attempting to perform this action.
4204/// \param RVal - The produced value will be placed here.
4205/// \param WantObjectRepresentation - If true, we're looking for the object
4206///               representation rather than the value, and in particular,
4207///               there is no requirement that the result be fully initialized.
4208static bool
4209handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type,
                             const LValue &LVal, APValue &RVal,
                             bool WantObjectRepresentation = false) {
if (LVal.Designator.Invalid)
69
←
Assuming field 'Invalid' is 0→
70
←
Taking false branch→
  return false;

// Check for special cases where there is no existing APValue to look at.
const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
71
←
Calling 'LValueBase::dyn_cast'→
81
←
Returning from 'LValueBase::dyn_cast'→

AccessKinds AK =
    WantObjectRepresentation81.1
'WantObjectRepresentation' is false
1
'WantObjectRepresentation' is false
1
'WantObjectRepresentation' is false
1
'WantObjectRepresentation' is false
1
'WantObjectRepresentation' is false
1
'WantObjectRepresentation' is false
 ? AK_ReadObjectRepresentation : AK_Read;
82
←
'?' condition is false→

if (Base82.1
'Base' is null
1
'Base' is null
1
'Base' is null
1
'Base' is null
1
'Base' is null
1
'Base' is null
 && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) {
  if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
    // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
    // initializer until now for such expressions. Such an expression can't be
    // an ICE in C, so this only matters for fold.
    if (Type.isVolatileQualified()) {
      Info.FFDiag(Conv);
      return false;
    }
    APValue Lit;
    if (!Evaluate(Lit, Info, CLE->getInitializer()))
      return false;
    CompleteObject LitObj(LVal.Base, &Lit, Base->getType());
    return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK);
  } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
    // Special-case character extraction so we don't have to construct an
    // APValue for the whole string.
    assert(LVal.Designator.Entries.size() <= 1 &&((void)0)
           "Can only read characters from string literals")((void)0);
    if (LVal.Designator.Entries.empty()) {
      // Fail for now for LValue to RValue conversion of an array.
      // (This shouldn't show up in C/C++, but it could be triggered by a
      // weird EvaluateAsRValue call from a tool.)
      Info.FFDiag(Conv);
      return false;
    }
    if (LVal.Designator.isOnePastTheEnd()) {
      if (Info.getLangOpts().CPlusPlus11)
        Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK;
      else
        Info.FFDiag(Conv);
      return false;
    }
    uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex();
    RVal = APValue(extractStringLiteralCharacter(Info, Base, CharIndex));
    return true;
  }
}

CompleteObject Obj = findCompleteObject(Info, Conv, AK, LVal, Type);
return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK);
83
←
Returning value, which participates in a condition later→
4262}

4264/// Perform an assignment of Val to LVal. Takes ownership of Val.
4265static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
                           QualType LValType, APValue &Val) {
if (LVal.Designator.Invalid)
  return false;

if (!Info.getLangOpts().CPlusPlus14) {
  Info.FFDiag(E);
  return false;
}

CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
4277}

4279namespace {
4280struct CompoundAssignSubobjectHandler {
EvalInfo &Info;
const CompoundAssignOperator *E;
QualType PromotedLHSType;
BinaryOperatorKind Opcode;
const APValue &RHS;

static const AccessKinds AccessKind = AK_Assign;

typedef bool result_type;

bool checkConst(QualType QT) {
  // Assigning to a const object has undefined behavior.
  if (QT.isConstQualified()) {
    Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
    return false;
  }
  return true;
}

bool failed() { return false; }
bool found(APValue &Subobj, QualType SubobjType) {
  switch (Subobj.getKind()) {
  case APValue::Int:
    return found(Subobj.getInt(), SubobjType);
  case APValue::Float:
    return found(Subobj.getFloat(), SubobjType);
  case APValue::ComplexInt:
  case APValue::ComplexFloat:
    // FIXME: Implement complex compound assignment.
    Info.FFDiag(E);
    return false;
  case APValue::LValue:
    return foundPointer(Subobj, SubobjType);
  case APValue::Vector:
    return foundVector(Subobj, SubobjType);
  default:
    // FIXME: can this happen?
    Info.FFDiag(E);
    return false;
  }
}

bool foundVector(APValue &Value, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;

  if (!SubobjType->isVectorType()) {
    Info.FFDiag(E);
    return false;
  }
  return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS);
}

bool found(APSInt &Value, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;

  if (!SubobjType->isIntegerType()) {
    // We don't support compound assignment on integer-cast-to-pointer
    // values.
    Info.FFDiag(E);
    return false;
  }

  if (RHS.isInt()) {
    APSInt LHS =
        HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value);
    if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
      return false;
    Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
    return true;
  } else if (RHS.isFloat()) {
    const FPOptions FPO = E->getFPFeaturesInEffect(
                                  Info.Ctx.getLangOpts());
    APFloat FValue(0.0);
    return HandleIntToFloatCast(Info, E, FPO, SubobjType, Value,
                                PromotedLHSType, FValue) &&
           handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) &&
           HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType,
                                Value);
  }

  Info.FFDiag(E);
  return false;
}
bool found(APFloat &Value, QualType SubobjType) {
  return checkConst(SubobjType) &&
         HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
                                Value) &&
         handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
         HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
}
bool foundPointer(APValue &Subobj, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;

  QualType PointeeType;
  if (const PointerType *PT = SubobjType->getAs<PointerType>())
    PointeeType = PT->getPointeeType();

  if (PointeeType.isNull() || !RHS.isInt() ||
      (Opcode != BO_Add && Opcode != BO_Sub)) {
    Info.FFDiag(E);
    return false;
  }

  APSInt Offset = RHS.getInt();
  if (Opcode == BO_Sub)
    negateAsSigned(Offset);

  LValue LVal;
  LVal.setFrom(Info.Ctx, Subobj);
  if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
    return false;
  LVal.moveInto(Subobj);
  return true;
}
4398};
4399} // end anonymous namespace

4401const AccessKinds CompoundAssignSubobjectHandler::AccessKind;

4403/// Perform a compound assignment of LVal <op>= RVal.
4404static bool handleCompoundAssignment(EvalInfo &Info,
                                   const CompoundAssignOperator *E,
                                   const LValue &LVal, QualType LValType,
                                   QualType PromotedLValType,
                                   BinaryOperatorKind Opcode,
                                   const APValue &RVal) {
if (LVal.Designator.Invalid)
  return false;

if (!Info.getLangOpts().CPlusPlus14) {
  Info.FFDiag(E);
  return false;
}

CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
                                           RVal };
return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4422}

4424namespace {
4425struct IncDecSubobjectHandler {
EvalInfo &Info;
const UnaryOperator *E;
AccessKinds AccessKind;
APValue *Old;

typedef bool result_type;

bool checkConst(QualType QT) {
  // Assigning to a const object has undefined behavior.
  if (QT.isConstQualified()) {
    Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
    return false;
  }
  return true;
}

bool failed() { return false; }
bool found(APValue &Subobj, QualType SubobjType) {
  // Stash the old value. Also clear Old, so we don't clobber it later
  // if we're post-incrementing a complex.
  if (Old) {
    *Old = Subobj;
    Old = nullptr;
  }

  switch (Subobj.getKind()) {
  case APValue::Int:
    return found(Subobj.getInt(), SubobjType);
  case APValue::Float:
    return found(Subobj.getFloat(), SubobjType);
  case APValue::ComplexInt:
    return found(Subobj.getComplexIntReal(),
                 SubobjType->castAs<ComplexType>()->getElementType()
                   .withCVRQualifiers(SubobjType.getCVRQualifiers()));
  case APValue::ComplexFloat:
    return found(Subobj.getComplexFloatReal(),
                 SubobjType->castAs<ComplexType>()->getElementType()
                   .withCVRQualifiers(SubobjType.getCVRQualifiers()));
  case APValue::LValue:
    return foundPointer(Subobj, SubobjType);
  default:
    // FIXME: can this happen?
    Info.FFDiag(E);
    return false;
  }
}
bool found(APSInt &Value, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;

  if (!SubobjType->isIntegerType()) {
    // We don't support increment / decrement on integer-cast-to-pointer
    // values.
    Info.FFDiag(E);
    return false;
  }

  if (Old) *Old = APValue(Value);

  // bool arithmetic promotes to int, and the conversion back to bool
  // doesn't reduce mod 2^n, so special-case it.
  if (SubobjType->isBooleanType()) {
    if (AccessKind == AK_Increment)
      Value = 1;
    else
      Value = !Value;
    return true;
  }

  bool WasNegative = Value.isNegative();
  if (AccessKind == AK_Increment) {
    ++Value;

    if (!WasNegative && Value.isNegative() && E->canOverflow()) {
      APSInt ActualValue(Value, /*IsUnsigned*/true);
      return HandleOverflow(Info, E, ActualValue, SubobjType);
    }
  } else {
    --Value;

    if (WasNegative && !Value.isNegative() && E->canOverflow()) {
      unsigned BitWidth = Value.getBitWidth();
      APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
      ActualValue.setBit(BitWidth);
      return HandleOverflow(Info, E, ActualValue, SubobjType);
    }
  }
  return true;
}
bool found(APFloat &Value, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;

  if (Old) *Old = APValue(Value);

  APFloat One(Value.getSemantics(), 1);
  if (AccessKind == AK_Increment)
    Value.add(One, APFloat::rmNearestTiesToEven);
  else
    Value.subtract(One, APFloat::rmNearestTiesToEven);
  return true;
}
bool foundPointer(APValue &Subobj, QualType SubobjType) {
  if (!checkConst(SubobjType))
    return false;

  QualType PointeeType;
  if (const PointerType *PT = SubobjType->getAs<PointerType>())
    PointeeType = PT->getPointeeType();
  else {
    Info.FFDiag(E);
    return false;
  }

  LValue LVal;
  LVal.setFrom(Info.Ctx, Subobj);
  if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
                                   AccessKind == AK_Increment ? 1 : -1))
    return false;
  LVal.moveInto(Subobj);
  return true;
}
4548};
4549} // end anonymous namespace

4551/// Perform an increment or decrement on LVal.
4552static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
                       QualType LValType, bool IsIncrement, APValue *Old) {
if (LVal.Designator.Invalid)
  return false;

if (!Info.getLangOpts().CPlusPlus14) {
  Info.FFDiag(E);
  return false;
}

AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old};
return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4566}

4568/// Build an lvalue for the object argument of a member function call.
4569static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
                                 LValue &This) {
if (Object->getType()->isPointerType() && Object->isPRValue())
  return EvaluatePointer(Object, This, Info);

if (Object->isGLValue())
  return EvaluateLValue(Object, This, Info);

if (Object->getType()->isLiteralType(Info.Ctx))
  return EvaluateTemporary(Object, This, Info);

Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
return false;
4582}

4584/// HandleMemberPointerAccess - Evaluate a member access operation and build an
4585/// lvalue referring to the result.
4586///
4587/// \param Info - Information about the ongoing evaluation.
4588/// \param LV - An lvalue referring to the base of the member pointer.
4589/// \param RHS - The member pointer expression.
4590/// \param IncludeMember - Specifies whether the member itself is included in
4591///        the resulting LValue subobject designator. This is not possible when
4592///        creating a bound member function.
4593/// \return The field or method declaration to which the member pointer refers,
4594///         or 0 if evaluation fails.
4595static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
                                                QualType LVType,
                                                LValue &LV,
                                                const Expr *RHS,
                                                bool IncludeMember = true) {
MemberPtr MemPtr;
if (!EvaluateMemberPointer(RHS, MemPtr, Info))
  return nullptr;

// C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
// member value, the behavior is undefined.
if (!MemPtr.getDecl()) {
  // FIXME: Specific diagnostic.
  Info.FFDiag(RHS);
  return nullptr;
}

if (MemPtr.isDerivedMember()) {
  // This is a member of some derived class. Truncate LV appropriately.
  // The end of the derived-to-base path for the base object must match the
  // derived-to-base path for the member pointer.
  if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
      LV.Designator.Entries.size()) {
    Info.FFDiag(RHS);
    return nullptr;
  }
  unsigned PathLengthToMember =
      LV.Designator.Entries.size() - MemPtr.Path.size();
  for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
    const CXXRecordDecl *LVDecl = getAsBaseClass(
        LV.Designator.Entries[PathLengthToMember + I]);
    const CXXRecordDecl *MPDecl = MemPtr.Path[I];
    if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
      Info.FFDiag(RHS);
      return nullptr;
    }
  }

  // Truncate the lvalue to the appropriate derived class.
  if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
                          PathLengthToMember))
    return nullptr;
} else if (!MemPtr.Path.empty()) {
  // Extend the LValue path with the member pointer's path.
  LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
                                MemPtr.Path.size() + IncludeMember);

  // Walk down to the appropriate base class.
  if (const PointerType *PT = LVType->getAs<PointerType>())
    LVType = PT->getPointeeType();
  const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
  assert(RD && "member pointer access on non-class-type expression")((void)0);
  // The first class in the path is that of the lvalue.
  for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
    const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
    if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
      return nullptr;
    RD = Base;
  }
  // Finally cast to the class containing the member.
  if (!HandleLValueDirectBase(Info, RHS, LV, RD,
                              MemPtr.getContainingRecord()))
    return nullptr;
}

// Add the member. Note that we cannot build bound member functions here.
if (IncludeMember) {
  if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
    if (!HandleLValueMember(Info, RHS, LV, FD))
      return nullptr;
  } else if (const IndirectFieldDecl *IFD =
               dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
    if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
      return nullptr;
  } else {
    llvm_unreachable("can't construct reference to bound member function")__builtin_unreachable();
  }
}

return MemPtr.getDecl();
4675}

4677static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
                                                const BinaryOperator *BO,
                                                LValue &LV,
                                                bool IncludeMember = true) {
assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI)((void)0);

if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
  if (Info.noteFailure()) {
    MemberPtr MemPtr;
    EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
  }
  return nullptr;
}

return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
                                 BO->getRHS(), IncludeMember);
4693}

4695/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
4696/// the provided lvalue, which currently refers to the base object.
4697static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
                                  LValue &Result) {
SubobjectDesignator &D = Result.Designator;
if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
  return false;

QualType TargetQT = E->getType();
if (const PointerType *PT = TargetQT->getAs<PointerType>())
  TargetQT = PT->getPointeeType();

// Check this cast lands within the final derived-to-base subobject path.
if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
  Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
    << D.MostDerivedType << TargetQT;
  return false;
}

// Check the type of the final cast. We don't need to check the path,
// since a cast can only be formed if the path is unique.
unsigned NewEntriesSize = D.Entries.size() - E->path_size();
const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
const CXXRecordDecl *FinalType;
if (NewEntriesSize == D.MostDerivedPathLength)
  FinalType = D.MostDerivedType->getAsCXXRecordDecl();
else
  FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
  Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
    << D.MostDerivedType << TargetQT;
  return false;
}

// Truncate the lvalue to the appropriate derived class.
return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
4731}

4733/// Get the value to use for a default-initialized object of type T.
4734/// Return false if it encounters something invalid.
4735static bool getDefaultInitValue(QualType T, APValue &Result) {
bool Success = true;
if (auto *RD = T->getAsCXXRecordDecl()) {
  if (RD->isInvalidDecl()) {
    Result = APValue();
    return false;
  }
  if (RD->isUnion()) {
    Result = APValue((const FieldDecl *)nullptr);
    return true;
  }
  Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
                   std::distance(RD->field_begin(), RD->field_end()));

  unsigned Index = 0;
  for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
                                                End = RD->bases_end();
       I != End; ++I, ++Index)
    Success &= getDefaultInitValue(I->getType(), Result.getStructBase(Index));

  for (const auto *I : RD->fields()) {
    if (I->isUnnamedBitfield())
      continue;
    Success &= getDefaultInitValue(I->getType(),
                                   Result.getStructField(I->getFieldIndex()));
  }
  return Success;
}

if (auto *AT =
        dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) {
  Result = APValue(APValue::UninitArray(), 0, AT->getSize().getZExtValue());
  if (Result.hasArrayFiller())
    Success &=
        getDefaultInitValue(AT->getElementType(), Result.getArrayFiller());

  return Success;
}

Result = APValue::IndeterminateValue();
return true;
4776}

4778namespace {
4779enum EvalStmtResult {
/// Evaluation failed.
ESR_Failed,
/// Hit a 'return' statement.
ESR_Returned,
/// Evaluation succeeded.
ESR_Succeeded,
/// Hit a 'continue' statement.
ESR_Continue,
/// Hit a 'break' statement.
ESR_Break,
/// Still scanning for 'case' or 'default' statement.
ESR_CaseNotFound
4792};
4793}

4795static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
// We don't need to evaluate the initializer for a static local.
if (!VD->hasLocalStorage())
  return true;

LValue Result;
APValue &Val = Info.CurrentCall->createTemporary(VD, VD->getType(),
                                                 ScopeKind::Block, Result);

const Expr *InitE = VD->getInit();
if (!InitE) {
  if (VD->getType()->isDependentType())
    return Info.noteSideEffect();
  return getDefaultInitValue(VD->getType(), Val);
}
if (InitE->isValueDependent())
  return false;

if (!EvaluateInPlace(Val, Info, Result, InitE)) {
  // Wipe out any partially-computed value, to allow tracking that this
  // evaluation failed.
  Val = APValue();
  return false;
}

return true;
4821}

4823static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
bool OK = true;

if (const VarDecl *VD = dyn_cast<VarDecl>(D))
  OK &= EvaluateVarDecl(Info, VD);

if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
  for (auto *BD : DD->bindings())
    if (auto *VD = BD->getHoldingVar())
      OK &= EvaluateDecl(Info, VD);

return OK;
4835}

4837static bool EvaluateDependentExpr(const Expr *E, EvalInfo &Info) {
assert(E->isValueDependent())((void)0);
if (Info.noteSideEffect())
  return true;
assert(E->containsErrors() && "valid value-dependent expression should never "((void)0)
                              "reach invalid code path.")((void)0);
return false;
4844}

4846/// Evaluate a condition (either a variable declaration or an expression).
4847static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
                       const Expr *Cond, bool &Result) {
if (Cond->isValueDependent())
  return false;
FullExpressionRAII Scope(Info);
if (CondDecl && !EvaluateDecl(Info, CondDecl))
  return false;
if (!EvaluateAsBooleanCondition(Cond, Result, Info))
  return false;
return Scope.destroy();
4857}

4859namespace {
4860/// A location where the result (returned value) of evaluating a
4861/// statement should be stored.
4862struct StmtResult {
/// The APValue that should be filled in with the returned value.
APValue &Value;
/// The location containing the result, if any (used to support RVO).
const LValue *Slot;
4867};

4869struct TempVersionRAII {
CallStackFrame &Frame;

TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) {
  Frame.pushTempVersion();
}

~TempVersionRAII() {
  Frame.popTempVersion();
}
4879};

4881}

4883static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
                                 const Stmt *S,
                                 const SwitchCase *SC = nullptr);

4887/// Evaluate the body of a loop, and translate the result as appropriate.
4888static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
                                     const Stmt *Body,
                                     const SwitchCase *Case = nullptr) {
BlockScopeRAII Scope(Info);

EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case);
if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
  ESR = ESR_Failed;

switch (ESR) {
case ESR_Break:
  return ESR_Succeeded;
case ESR_Succeeded:
case ESR_Continue:
  return ESR_Continue;
case ESR_Failed:
case ESR_Returned:
case ESR_CaseNotFound:
  return ESR;
}
llvm_unreachable("Invalid EvalStmtResult!")__builtin_unreachable();
4909}

4911/// Evaluate a switch statement.
4912static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
                                   const SwitchStmt *SS) {
BlockScopeRAII Scope(Info);

// Evaluate the switch condition.
APSInt Value;
{
  if (const Stmt *Init = SS->getInit()) {
    EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
    if (ESR != ESR_Succeeded) {
      if (ESR != ESR_Failed && !Scope.destroy())
        ESR = ESR_Failed;
      return ESR;
    }
  }

  FullExpressionRAII CondScope(Info);
  if (SS->getConditionVariable() &&
      !EvaluateDecl(Info, SS->getConditionVariable()))
    return ESR_Failed;
  if (!EvaluateInteger(SS->getCond(), Value, Info))
    return ESR_Failed;
  if (!CondScope.destroy())
    return ESR_Failed;
}

// Find the switch case corresponding to the value of the condition.
// FIXME: Cache this lookup.
const SwitchCase *Found = nullptr;
for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
     SC = SC->getNextSwitchCase()) {
  if (isa<DefaultStmt>(SC)) {
    Found = SC;
    continue;
  }

  const CaseStmt *CS = cast<CaseStmt>(SC);
  APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
  APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
                            : LHS;
  if (LHS <= Value && Value <= RHS) {
    Found = SC;
    break;
  }
}

if (!Found)
  return Scope.destroy() ? ESR_Succeeded : ESR_Failed;

// Search the switch body for the switch case and evaluate it from there.
EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found);
if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
  return ESR_Failed;

switch (ESR) {
case ESR_Break:
  return ESR_Succeeded;
case ESR_Succeeded:
case ESR_Continue:
case ESR_Failed:
case ESR_Returned:
  return ESR;
case ESR_CaseNotFound:
  // This can only happen if the switch case is nested within a statement
  // expression. We have no intention of supporting that.
  Info.FFDiag(Found->getBeginLoc(),
              diag::note_constexpr_stmt_expr_unsupported);
  return ESR_Failed;
}
llvm_unreachable("Invalid EvalStmtResult!")__builtin_unreachable();
4982}

4984// Evaluate a statement.
4985static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
                                 const Stmt *S, const SwitchCase *Case) {
if (!Info.nextStep(S))
  return ESR_Failed;

// If we're hunting down a 'case' or 'default' label, recurse through
// substatements until we hit the label.
if (Case) {
  switch (S->getStmtClass()) {
  case Stmt::CompoundStmtClass:
    // FIXME: Precompute which substatement of a compound statement we
    // would jump to, and go straight there rather than performing a
    // linear scan each time.
  case Stmt::LabelStmtClass:
  case Stmt::AttributedStmtClass:
  case Stmt::DoStmtClass:
    break;

  case Stmt::CaseStmtClass:
  case Stmt::DefaultStmtClass:
    if (Case == S)
      Case = nullptr;
    break;

  case Stmt::IfStmtClass: {
    // FIXME: Precompute which side of an 'if' we would jump to, and go
    // straight there rather than scanning both sides.
    const IfStmt *IS = cast<IfStmt>(S);

    // Wrap the evaluation in a block scope, in case it's a DeclStmt
    // preceded by our switch label.
    BlockScopeRAII Scope(Info);

    // Step into the init statement in case it brings an (uninitialized)
    // variable into scope.
    if (const Stmt *Init = IS->getInit()) {
      EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
      if (ESR != ESR_CaseNotFound) {
        assert(ESR != ESR_Succeeded)((void)0);
        return ESR;
      }
    }

    // Condition variable must be initialized if it exists.
    // FIXME: We can skip evaluating the body if there's a condition
    // variable, as there can't be any case labels within it.
    // (The same is true for 'for' statements.)

    EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
    if (ESR == ESR_Failed)
      return ESR;
    if (ESR != ESR_CaseNotFound)
      return Scope.destroy() ? ESR : ESR_Failed;
    if (!IS->getElse())
      return ESR_CaseNotFound;

    ESR = EvaluateStmt(Result, Info, IS->getElse(), Case);
    if (ESR == ESR_Failed)
      return ESR;
    if (ESR != ESR_CaseNotFound)
      return Scope.destroy() ? ESR : ESR_Failed;
    return ESR_CaseNotFound;
  }

  case Stmt::WhileStmtClass: {
    EvalStmtResult ESR =
        EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
    if (ESR != ESR_Continue)
      return ESR;
    break;
  }

  case Stmt::ForStmtClass: {
    const ForStmt *FS = cast<ForStmt>(S);
    BlockScopeRAII Scope(Info);

    // Step into the init statement in case it brings an (uninitialized)
    // variable into scope.
    if (const Stmt *Init = FS->getInit()) {
      EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
      if (ESR != ESR_CaseNotFound) {
        assert(ESR != ESR_Succeeded)((void)0);
        return ESR;
      }
    }

    EvalStmtResult ESR =
        EvaluateLoopBody(Result, Info, FS->getBody(), Case);
    if (ESR != ESR_Continue)
      return ESR;
    if (const auto *Inc = FS->getInc()) {
      if (Inc->isValueDependent()) {
        if (!EvaluateDependentExpr(Inc, Info))
          return ESR_Failed;
      } else {
        FullExpressionRAII IncScope(Info);
        if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy())
          return ESR_Failed;
      }
    }
    break;
  }

  case Stmt::DeclStmtClass: {
    // Start the lifetime of any uninitialized variables we encounter. They
    // might be used by the selected branch of the switch.
    const DeclStmt *DS = cast<DeclStmt>(S);
    for (const auto *D : DS->decls()) {
      if (const auto *VD = dyn_cast<VarDecl>(D)) {
        if (VD->hasLocalStorage() && !VD->getInit())
          if (!EvaluateVarDecl(Info, VD))
            return ESR_Failed;
        // FIXME: If the variable has initialization that can't be jumped
        // over, bail out of any immediately-surrounding compound-statement
        // too. There can't be any case labels here.
      }
    }
    return ESR_CaseNotFound;
  }

  default:
    return ESR_CaseNotFound;
  }
}

switch (S->getStmtClass()) {
default:
  if (const Expr *E = dyn_cast<Expr>(S)) {
    if (E->isValueDependent()) {
      if (!EvaluateDependentExpr(E, Info))
        return ESR_Failed;
    } else {
      // Don't bother evaluating beyond an expression-statement which couldn't
      // be evaluated.
      // FIXME: Do we need the FullExpressionRAII object here?
      // VisitExprWithCleanups should create one when necessary.
      FullExpressionRAII Scope(Info);
      if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy())
        return ESR_Failed;
    }
    return ESR_Succeeded;
  }

  Info.FFDiag(S->getBeginLoc());
  return ESR_Failed;

case Stmt::NullStmtClass:
  return ESR_Succeeded;

case Stmt::DeclStmtClass: {
  const DeclStmt *DS = cast<DeclStmt>(S);
  for (const auto *D : DS->decls()) {
    // Each declaration initialization is its own full-expression.
    FullExpressionRAII Scope(Info);
    if (!EvaluateDecl(Info, D) && !Info.noteFailure())
      return ESR_Failed;
    if (!Scope.destroy())
      return ESR_Failed;
  }
  return ESR_Succeeded;
}

case Stmt::ReturnStmtClass: {
  const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
  FullExpressionRAII Scope(Info);
  if (RetExpr && RetExpr->isValueDependent()) {
    EvaluateDependentExpr(RetExpr, Info);
    // We know we returned, but we don't know what the value is.
    return ESR_Failed;
  }
  if (RetExpr &&
      !(Result.Slot
            ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
            : Evaluate(Result.Value, Info, RetExpr)))
    return ESR_Failed;
  return Scope.destroy() ? ESR_Returned : ESR_Failed;
}

case Stmt::CompoundStmtClass: {
  BlockScopeRAII Scope(Info);

  const CompoundStmt *CS = cast<CompoundStmt>(S);
  for (const auto *BI : CS->body()) {
    EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
    if (ESR == ESR_Succeeded)
      Case = nullptr;
    else if (ESR != ESR_CaseNotFound) {
      if (ESR != ESR_Failed && !Scope.destroy())
        return ESR_Failed;
      return ESR;
    }
  }
  if (Case)
    return ESR_CaseNotFound;
  return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
}

case Stmt::IfStmtClass: {
  const IfStmt *IS = cast<IfStmt>(S);

  // Evaluate the condition, as either a var decl or as an expression.
  BlockScopeRAII Scope(Info);
  if (const Stmt *Init = IS->getInit()) {
    EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
    if (ESR != ESR_Succeeded) {
      if (ESR != ESR_Failed && !Scope.destroy())
        return ESR_Failed;
      return ESR;
    }
  }
  bool Cond;
  if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
    return ESR_Failed;

  if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
    EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
    if (ESR != ESR_Succeeded) {
      if (ESR != ESR_Failed && !Scope.destroy())
        return ESR_Failed;
      return ESR;
    }
  }
  return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
}

case Stmt::WhileStmtClass: {
  const WhileStmt *WS = cast<WhileStmt>(S);
  while (true) {
    BlockScopeRAII Scope(Info);
    bool Continue;
    if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
                      Continue))
      return ESR_Failed;
    if (!Continue)
      break;

    EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
    if (ESR != ESR_Continue) {
      if (ESR != ESR_Failed && !Scope.destroy())
        return ESR_Failed;
      return ESR;
    }
    if (!Scope.destroy())
      return ESR_Failed;
  }
  return ESR_Succeeded;
}

case Stmt::DoStmtClass: {
  const DoStmt *DS = cast<DoStmt>(S);
  bool Continue;
  do {
    EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
    if (ESR != ESR_Continue)
      return ESR;
    Case = nullptr;

    if (DS->getCond()->isValueDependent()) {
      EvaluateDependentExpr(DS->getCond(), Info);
      // Bailout as we don't know whether to keep going or terminate the loop.
      return ESR_Failed;
    }
    FullExpressionRAII CondScope(Info);
    if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info) ||
        !CondScope.destroy())
      return ESR_Failed;
  } while (Continue);
  return ESR_Succeeded;
}

case Stmt::ForStmtClass: {
  const ForStmt *FS = cast<ForStmt>(S);
  BlockScopeRAII ForScope(Info);
  if (FS->getInit()) {
    EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
    if (ESR != ESR_Succeeded) {
      if (ESR != ESR_Failed && !ForScope.destroy())
        return ESR_Failed;
      return ESR;
    }
  }
  while (true) {
    BlockScopeRAII IterScope(Info);
    bool Continue = true;
    if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
                                       FS->getCond(), Continue))
      return ESR_Failed;
    if (!Continue)
      break;

    EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
    if (ESR != ESR_Continue) {
      if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy()))
        return ESR_Failed;
      return ESR;
    }

    if (const auto *Inc = FS->getInc()) {
      if (Inc->isValueDependent()) {
        if (!EvaluateDependentExpr(Inc, Info))
          return ESR_Failed;
      } else {
        FullExpressionRAII IncScope(Info);
        if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy())
          return ESR_Failed;
      }
    }

    if (!IterScope.destroy())
      return ESR_Failed;
  }
  return ForScope.destroy() ? ESR_Succeeded : ESR_Failed;
}

case Stmt::CXXForRangeStmtClass: {
  const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
  BlockScopeRAII Scope(Info);

  // Evaluate the init-statement if present.
  if (FS->getInit()) {
    EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
    if (ESR != ESR_Succeeded) {
      if (ESR != ESR_Failed && !Scope.destroy())
        return ESR_Failed;
      return ESR;
    }
  }

  // Initialize the __range variable.
  EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
  if (ESR != ESR_Succeeded) {
    if (ESR != ESR_Failed && !Scope.destroy())
      return ESR_Failed;
    return ESR;
  }

  // Create the __begin and __end iterators.
  ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
  if (ESR != ESR_Succeeded) {
    if (ESR != ESR_Failed && !Scope.destroy())
      return ESR_Failed;
    return ESR;
  }
  ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
  if (ESR != ESR_Succeeded) {
    if (ESR != ESR_Failed && !Scope.destroy())
      return ESR_Failed;
    return ESR;
  }

  while (true) {
    // Condition: __begin != __end.
    {
      if (FS->getCond()->isValueDependent()) {
        EvaluateDependentExpr(FS->getCond(), Info);
        // We don't know whether to keep going or terminate the loop.
        return ESR_Failed;
      }
      bool Continue = true;
      FullExpressionRAII CondExpr(Info);
      if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
        return ESR_Failed;
      if (!Continue)
        break;
    }

    // User's variable declaration, initialized by *__begin.
    BlockScopeRAII InnerScope(Info);
    ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
    if (ESR != ESR_Succeeded) {
      if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
        return ESR_Failed;
      return ESR;
    }

    // Loop body.
    ESR = EvaluateLoopBody(Result, Info, FS->getBody());
    if (ESR != ESR_Continue) {
      if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
        return ESR_Failed;
      return ESR;
    }
    if (FS->getInc()->isValueDependent()) {
      if (!EvaluateDependentExpr(FS->getInc(), Info))
        return ESR_Failed;
    } else {
      // Increment: ++__begin
      if (!EvaluateIgnoredValue(Info, FS->getInc()))
        return ESR_Failed;
    }

    if (!InnerScope.destroy())
      return ESR_Failed;
  }

  return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
}

case Stmt::SwitchStmtClass:
  return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));

case Stmt::ContinueStmtClass:
  return ESR_Continue;

case Stmt::BreakStmtClass:
  return ESR_Break;

case Stmt::LabelStmtClass:
  return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);

case Stmt::AttributedStmtClass:
  // As a general principle, C++11 attributes can be ignored without
  // any semantic impact.
  return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
                      Case);

case Stmt::CaseStmtClass:
case Stmt::DefaultStmtClass:
  return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
case Stmt::CXXTryStmtClass:
  // Evaluate try blocks by evaluating all sub statements.
  return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case);
}
5408}

5410/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
5411/// default constructor. If so, we'll fold it whether or not it's marked as
5412/// constexpr. If it is marked as constexpr, we will never implicitly define it,
5413/// so we need special handling.
5414static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
                                         const CXXConstructorDecl *CD,
                                         bool IsValueInitialization) {
if (!CD->isTrivial() || !CD->isDefaultConstructor())
  return false;

// Value-initialization does not call a trivial default constructor, so such a
// call is a core constant expression whether or not the constructor is
// constexpr.
if (!CD->isConstexpr() && !IsValueInitialization) {
  if (Info.getLangOpts().CPlusPlus11) {
    // FIXME: If DiagDecl is an implicitly-declared special member function,
    // we should be much more explicit about why it's not constexpr.
    Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
      << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
    Info.Note(CD->getLocation(), diag::note_declared_at);
  } else {
    Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
  }
}
return true;
5435}

5437/// CheckConstexprFunction - Check that a function can be called in a constant
5438/// expression.
5439static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
                                 const FunctionDecl *Declaration,
                                 const FunctionDecl *Definition,
                                 const Stmt *Body) {
// Potential constant expressions can contain calls to declared, but not yet
// defined, constexpr functions.
if (Info.checkingPotentialConstantExpression() && !Definition &&
    Declaration->isConstexpr())
  return false;

// Bail out if the function declaration itself is invalid.  We will
// have produced a relevant diagnostic while parsing it, so just
// note the problematic sub-expression.
if (Declaration->isInvalidDecl()) {
  Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
  return false;
}

// DR1872: An instantiated virtual constexpr function can't be called in a
// constant expression (prior to C++20). We can still constant-fold such a
// call.
if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) &&
    cast<CXXMethodDecl>(Declaration)->isVirtual())
  Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call);

if (Definition && Definition->isInvalidDecl()) {
  Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
  return false;
}

// Can we evaluate this function call?
if (Definition && Definition->isConstexpr() && Body)
  return true;

if (Info.getLangOpts().CPlusPlus11) {
  const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;

  // If this function is not constexpr because it is an inherited
  // non-constexpr constructor, diagnose that directly.
  auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
  if (CD && CD->isInheritingConstructor()) {
    auto *Inherited = CD->getInheritedConstructor().getConstructor();
    if (!Inherited->isConstexpr())
      DiagDecl = CD = Inherited;
  }

  // FIXME: If DiagDecl is an implicitly-declared special member function
  // or an inheriting constructor, we should be much more explicit about why
  // it's not constexpr.
  if (CD && CD->isInheritingConstructor())
    Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
      << CD->getInheritedConstructor().getConstructor()->getParent();
  else
    Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
      << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
  Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
} else {
  Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
}
return false;
5499}

5501namespace {
5502struct CheckDynamicTypeHandler {
AccessKinds AccessKind;
typedef bool result_type;
bool failed() { return false; }
bool found(APValue &Subobj, QualType SubobjType) { return true; }
bool found(APSInt &Value, QualType SubobjType) { return true; }
bool found(APFloat &Value, QualType SubobjType) { return true; }
5509};
5510} // end anonymous namespace

5512/// Check that we can access the notional vptr of an object / determine its
5513/// dynamic type.
5514static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This,
                           AccessKinds AK, bool Polymorphic) {
if (This.Designator.Invalid)
  return false;

CompleteObject Obj = findCompleteObject(Info, E, AK, This, QualType());

if (!Obj)
  return false;

if (!Obj.Value) {
  // The object is not usable in constant expressions, so we can't inspect
  // its value to see if it's in-lifetime or what the active union members
  // are. We can still check for a one-past-the-end lvalue.
  if (This.Designator.isOnePastTheEnd() ||
      This.Designator.isMostDerivedAnUnsizedArray()) {
    Info.FFDiag(E, This.Designator.isOnePastTheEnd()
                       ? diag::note_constexpr_access_past_end
                       : diag::note_constexpr_access_unsized_array)
        << AK;
    return false;
  } else if (Polymorphic) {
    // Conservatively refuse to perform a polymorphic operation if we would
    // not be able to read a notional 'vptr' value.
    APValue Val;
    This.moveInto(Val);
    QualType StarThisType =
        Info.Ctx.getLValueReferenceType(This.Designator.getType(Info.Ctx));
    Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type)
        << AK << Val.getAsString(Info.Ctx, StarThisType);
    return false;
  }
  return true;
}

CheckDynamicTypeHandler Handler{AK};
return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
5551}

5553/// Check that the pointee of the 'this' pointer in a member function call is
5554/// either within its lifetime or in its period of construction or destruction.
5555static bool
5556checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E,
                                   const LValue &This,
                                   const CXXMethodDecl *NamedMember) {
return checkDynamicType(
    Info, E, This,
    isa<CXXDestructorDecl>(NamedMember) ? AK_Destroy : AK_MemberCall, false);
5562}

5564struct DynamicType {
/// The dynamic class type of the object.
const CXXRecordDecl *Type;
/// The corresponding path length in the lvalue.
unsigned PathLength;
5569};

5571static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator,
                                           unsigned PathLength) {
assert(PathLength >= Designator.MostDerivedPathLength && PathLength <=((void)0)
    Designator.Entries.size() && "invalid path length")((void)0);
return (PathLength == Designator.MostDerivedPathLength)
           ? Designator.MostDerivedType->getAsCXXRecordDecl()
           : getAsBaseClass(Designator.Entries[PathLength - 1]);
5578}

5580/// Determine the dynamic type of an object.
5581static Optional<DynamicType> ComputeDynamicType(EvalInfo &Info, const Expr *E,
                                              LValue &This, AccessKinds AK) {
// If we don't have an lvalue denoting an object of class type, there is no
// meaningful dynamic type. (We consider objects of non-class type to have no
// dynamic type.)
if (!checkDynamicType(Info, E, This, AK, true))
  return None;

// Refuse to compute a dynamic type in the presence of virtual bases. This
// shouldn't happen other than in constant-folding situations, since literal
// types can't have virtual bases.
//
// Note that consumers of DynamicType assume that the type has no virtual
// bases, and will need modifications if this restriction is relaxed.
const CXXRecordDecl *Class =
    This.Designator.MostDerivedType->getAsCXXRecordDecl();
if (!Class || Class->getNumVBases()) {
  Info.FFDiag(E);
  return None;
}

// FIXME: For very deep class hierarchies, it might be beneficial to use a
// binary search here instead. But the overwhelmingly common case is that
// we're not in the middle of a constructor, so it probably doesn't matter
// in practice.
ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries;
for (unsigned PathLength = This.Designator.MostDerivedPathLength;
     PathLength <= Path.size(); ++PathLength) {
  switch (Info.isEvaluatingCtorDtor(This.getLValueBase(),
                                    Path.slice(0, PathLength))) {
  case ConstructionPhase::Bases:
  case ConstructionPhase::DestroyingBases:
    // We're constructing or destroying a base class. This is not the dynamic
    // type.
    break;

  case ConstructionPhase::None:
  case ConstructionPhase::AfterBases:
  case ConstructionPhase::AfterFields:
  case ConstructionPhase::Destroying:
    // We've finished constructing the base classes and not yet started
    // destroying them again, so this is the dynamic type.
    return DynamicType{getBaseClassType(This.Designator, PathLength),
                       PathLength};
  }
}

// CWG issue 1517: we're constructing a base class of the object described by
// 'This', so that object has not yet begun its period of construction and
// any polymorphic operation on it results in undefined behavior.
Info.FFDiag(E);
return None;
5633}

5635/// Perform virtual dispatch.
5636static const CXXMethodDecl *HandleVirtualDispatch(
  EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found,
  llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) {
Optional<DynamicType> DynType = ComputeDynamicType(
    Info, E, This,
    isa<CXXDestructorDecl>(Found) ? AK_Destroy : AK_MemberCall);
if (!DynType)
  return nullptr;

// Find the final overrider. It must be declared in one of the classes on the
// path from the dynamic type to the static type.
// FIXME: If we ever allow literal types to have virtual base classes, that
// won't be true.
const CXXMethodDecl *Callee = Found;
unsigned PathLength = DynType->PathLength;
for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) {
  const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength);
  const CXXMethodDecl *Overrider =
      Found->getCorrespondingMethodDeclaredInClass(Class, false);
  if (Overrider) {
    Callee = Overrider;
    break;
  }
}

// C++2a [class.abstract]p6:
//   the effect of making a virtual call to a pure virtual function [...] is
//   undefined
if (Callee->isPure()) {
  Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee;
  Info.Note(Callee->getLocation(), diag::note_declared_at);
  return nullptr;
}

// If necessary, walk the rest of the path to determine the sequence of
// covariant adjustment steps to apply.
if (!Info.Ctx.hasSameUnqualifiedType(Callee->getReturnType(),
                                     Found->getReturnType())) {
  CovariantAdjustmentPath.push_back(Callee->getReturnType());
  for (unsigned CovariantPathLength = PathLength + 1;
       CovariantPathLength != This.Designator.Entries.size();
       ++CovariantPathLength) {
    const CXXRecordDecl *NextClass =
        getBaseClassType(This.Designator, CovariantPathLength);
    const CXXMethodDecl *Next =
        Found->getCorrespondingMethodDeclaredInClass(NextClass, false);
    if (Next && !Info.Ctx.hasSameUnqualifiedType(
                    Next->getReturnType(), CovariantAdjustmentPath.back()))
      CovariantAdjustmentPath.push_back(Next->getReturnType());
  }
  if (!Info.Ctx.hasSameUnqualifiedType(Found->getReturnType(),
                                       CovariantAdjustmentPath.back()))
    CovariantAdjustmentPath.push_back(Found->getReturnType());
}

// Perform 'this' adjustment.
if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength))
  return nullptr;

return Callee;
5696}

5698/// Perform the adjustment from a value returned by a virtual function to
5699/// a value of the statically expected type, which may be a pointer or
5700/// reference to a base class of the returned type.
5701static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E,
                                          APValue &Result,
                                          ArrayRef<QualType> Path) {
assert(Result.isLValue() &&((void)0)
       "unexpected kind of APValue for covariant return")((void)0);
if (Result.isNullPointer())
  return true;

LValue LVal;
LVal.setFrom(Info.Ctx, Result);

const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl();
for (unsigned I = 1; I != Path.size(); ++I) {
  const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl();
  assert(OldClass && NewClass && "unexpected kind of covariant return")((void)0);
  if (OldClass != NewClass &&
      !CastToBaseClass(Info, E, LVal, OldClass, NewClass))
    return false;
  OldClass = NewClass;
}

LVal.moveInto(Result);
return true;
5724}

5726/// Determine whether \p Base, which is known to be a direct base class of
5727/// \p Derived, is a public base class.
5728static bool isBaseClassPublic(const CXXRecordDecl *Derived,
                            const CXXRecordDecl *Base) {
for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) {
  auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl();
  if (BaseClass && declaresSameEntity(BaseClass, Base))
    return BaseSpec.getAccessSpecifier() == AS_public;
}
llvm_unreachable("Base is not a direct base of Derived")__builtin_unreachable();
5736}

5738/// Apply the given dynamic cast operation on the provided lvalue.
5739///
5740/// This implements the hard case of dynamic_cast, requiring a "runtime check"
5741/// to find a suitable target subobject.
5742static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E,
                            LValue &Ptr) {
// We can't do anything with a non-symbolic pointer value.
SubobjectDesignator &D = Ptr.Designator;
if (D.Invalid)
  return false;

// C++ [expr.dynamic.cast]p6:
//   If v is a null pointer value, the result is a null pointer value.
if (Ptr.isNullPointer() && !E->isGLValue())
  return true;

// For all the other cases, we need the pointer to point to an object within
// its lifetime / period of construction / destruction, and we need to know
// its dynamic type.
Optional<DynamicType> DynType =
    ComputeDynamicType(Info, E, Ptr, AK_DynamicCast);
if (!DynType)
  return false;

// C++ [expr.dynamic.cast]p7:
//   If T is "pointer to cv void", then the result is a pointer to the most
//   derived object
if (E->getType()->isVoidPointerType())
  return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength);

const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl();
assert(C && "dynamic_cast target is not void pointer nor class")((void)0);
CanQualType CQT = Info.Ctx.getCanonicalType(Info.Ctx.getRecordType(C));

auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) {
  // C++ [expr.dynamic.cast]p9:
  if (!E->isGLValue()) {
    //   The value of a failed cast to pointer type is the null pointer value
    //   of the required result type.
    Ptr.setNull(Info.Ctx, E->getType());
    return true;
  }

  //   A failed cast to reference type throws [...] std::bad_cast.
  unsigned DiagKind;
  if (!Paths && (declaresSameEntity(DynType->Type, C) ||
                 DynType->Type->isDerivedFrom(C)))
    DiagKind = 0;
  else if (!Paths || Paths->begin() == Paths->end())
    DiagKind = 1;
  else if (Paths->isAmbiguous(CQT))
    DiagKind = 2;
  else {
    assert(Paths->front().Access != AS_public && "why did the cast fail?")((void)0);
    DiagKind = 3;
  }
  Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed)
      << DiagKind << Ptr.Designator.getType(Info.Ctx)
      << Info.Ctx.getRecordType(DynType->Type)
      << E->getType().getUnqualifiedType();
  return false;
};

// Runtime check, phase 1:
//   Walk from the base subobject towards the derived object looking for the
//   target type.
for (int PathLength = Ptr.Designator.Entries.size();
     PathLength >= (int)DynType->PathLength; --PathLength) {
  const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength);
  if (declaresSameEntity(Class, C))
    return CastToDerivedClass(Info, E, Ptr, Class, PathLength);
  // We can only walk across public inheritance edges.
  if (PathLength > (int)DynType->PathLength &&
      !isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1),
                         Class))
    return RuntimeCheckFailed(nullptr);
}

// Runtime check, phase 2:
//   Search the dynamic type for an unambiguous public base of type C.
CXXBasePaths Paths(/*FindAmbiguities=*/true,
                   /*RecordPaths=*/true, /*DetectVirtual=*/false);
if (DynType->Type->isDerivedFrom(C, Paths) && !Paths.isAmbiguous(CQT) &&
    Paths.front().Access == AS_public) {
  // Downcast to the dynamic type...
  if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength))
    return false;
  // ... then upcast to the chosen base class subobject.
  for (CXXBasePathElement &Elem : Paths.front())
    if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base))
      return false;
  return true;
}

// Otherwise, the runtime check fails.
return RuntimeCheckFailed(&Paths);
5834}

5836namespace {
5837struct StartLifetimeOfUnionMemberHandler {
EvalInfo &Info;
const Expr *LHSExpr;
const FieldDecl *Field;
bool DuringInit;
bool Failed = false;
static const AccessKinds AccessKind = AK_Assign;

typedef bool result_type;
bool failed() { return Failed; }
bool found(APValue &Subobj, QualType SubobjType) {
  // We are supposed to perform no initialization but begin the lifetime of
  // the object. We interpret that as meaning to do what default
  // initialization of the object would do if all constructors involved were
  // trivial:
  //  * All base, non-variant member, and array element subobjects' lifetimes
  //    begin
  //  * No variant members' lifetimes begin
  //  * All scalar subobjects whose lifetimes begin have indeterminate values
  assert(SubobjType->isUnionType())((void)0);
  if (declaresSameEntity(Subobj.getUnionField(), Field)) {
    // This union member is already active. If it's also in-lifetime, there's
    // nothing to do.
    if (Subobj.getUnionValue().hasValue())
      return true;
  } else if (DuringInit) {
    // We're currently in the process of initializing a different union
    // member.  If we carried on, that initialization would attempt to
    // store to an inactive union member, resulting in undefined behavior.
    Info.FFDiag(LHSExpr,
                diag::note_constexpr_union_member_change_during_init);
    return false;
  }
  APValue Result;
  Failed = !getDefaultInitValue(Field->getType(), Result);
  Subobj.setUnion(Field, Result);
  return true;
}
bool found(APSInt &Value, QualType SubobjType) {
  llvm_unreachable("wrong value kind for union object")__builtin_unreachable();
}
bool found(APFloat &Value, QualType SubobjType) {
  llvm_unreachable("wrong value kind for union object")__builtin_unreachable();
}
5881};
5882} // end anonymous namespace

5884const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind;

5886/// Handle a builtin simple-assignment or a call to a trivial assignment
5887/// operator whose left-hand side might involve a union member access. If it
5888/// does, implicitly start the lifetime of any accessed union elements per
5889/// C++20 [class.union]5.
5890static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr,
                                        const LValue &LHS) {
if (LHS.InvalidBase || LHS.Designator.Invalid)
92
←
Assuming field 'InvalidBase' is false→
93
←
Assuming field 'Invalid' is 0→
94
←
Taking false branch→
  return false;

llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths;
// C++ [class.union]p5:
//   define the set S(E) of subexpressions of E as follows:
unsigned PathLength = LHS.Designator.Entries.size();
for (const Expr *E = LHSExpr; E != nullptr;) {
95
←
Assuming pointer value is null→
96
←
Loop condition is false. Execution continues on line 5960→
  //   -- If E is of the form A.B, S(E) contains the elements of S(A)...
  if (auto *ME = dyn_cast<MemberExpr>(E)) {
    auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
    // Note that we can't implicitly start the lifetime of a reference,
    // so we don't need to proceed any further if we reach one.
    if (!FD || FD->getType()->isReferenceType())
      break;

    //    ... and also contains A.B if B names a union member ...
    if (FD->getParent()->isUnion()) {
      //    ... of a non-class, non-array type, or of a class type with a
      //    trivial default constructor that is not deleted, or an array of
      //    such types.
      auto *RD =
          FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
      if (!RD || RD->hasTrivialDefaultConstructor())
        UnionPathLengths.push_back({PathLength - 1, FD});
    }

    E = ME->getBase();
    --PathLength;
    assert(declaresSameEntity(FD,((void)0)
                              LHS.Designator.Entries[PathLength]((void)0)
                                  .getAsBaseOrMember().getPointer()))((void)0);

    //   -- If E is of the form A[B] and is interpreted as a built-in array
    //      subscripting operator, S(E) is [S(the array operand, if any)].
  } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
    // Step over an ArrayToPointerDecay implicit cast.
    auto *Base = ASE->getBase()->IgnoreImplicit();
    if (!Base->getType()->isArrayType())
      break;

    E = Base;
    --PathLength;

  } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) {
    // Step over a derived-to-base conversion.
    E = ICE->getSubExpr();
    if (ICE->getCastKind() == CK_NoOp)
      continue;
    if (ICE->getCastKind() != CK_DerivedToBase &&
        ICE->getCastKind() != CK_UncheckedDerivedToBase)
      break;
    // Walk path backwards as we walk up from the base to the derived class.
    for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) {
      --PathLength;
      (void)Elt;
      assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),((void)0)
                                LHS.Designator.Entries[PathLength]((void)0)
                                    .getAsBaseOrMember().getPointer()))((void)0);
    }

  //   -- Otherwise, S(E) is empty.
  } else {
    break;
  }
}

// Common case: no unions' lifetimes are started.
if (UnionPathLengths.empty())
97
←
Calling 'SmallVectorBase::empty'→
100
←
Returning from 'SmallVectorBase::empty'→
101
←
Taking false branch→
  return true;

//   if modification of X [would access an inactive union member], an object
//   of the type of X is implicitly created
CompleteObject Obj =
    findCompleteObject(Info, LHSExpr, AK_Assign, LHS, LHSExpr->getType());
102
←
Called C++ object pointer is null
if (!Obj)
  return false;
for (std::pair<unsigned, const FieldDecl *> LengthAndField :
         llvm::reverse(UnionPathLengths)) {
  // Form a designator for the union object.
  SubobjectDesignator D = LHS.Designator;
  D.truncate(Info.Ctx, LHS.Base, LengthAndField.first);

  bool DuringInit = Info.isEvaluatingCtorDtor(LHS.Base, D.Entries) ==
                    ConstructionPhase::AfterBases;
  StartLifetimeOfUnionMemberHandler StartLifetime{
      Info, LHSExpr, LengthAndField.second, DuringInit};
  if (!findSubobject(Info, LHSExpr, Obj, D, StartLifetime))
    return false;
}

return true;
5984}

5986static bool EvaluateCallArg(const ParmVarDecl *PVD, const Expr *Arg,
                          CallRef Call, EvalInfo &Info,
                          bool NonNull = false) {
LValue LV;
// Create the parameter slot and register its destruction. For a vararg
// argument, create a temporary.
// FIXME: For calling conventions that destroy parameters in the callee,
// should we consider performing destruction when the function returns
// instead?
APValue &V = PVD ? Info.CurrentCall->createParam(Call, PVD, LV)
                 : Info.CurrentCall->createTemporary(Arg, Arg->getType(),
                                                     ScopeKind::Call, LV);
if (!EvaluateInPlace(V, Info, LV, Arg))
  return false;

// Passing a null pointer to an __attribute__((nonnull)) parameter results in
// undefined behavior, so is non-constant.
if (NonNull && V.isLValue() && V.isNullPointer()) {
  Info.CCEDiag(Arg, diag::note_non_null_attribute_failed);
  return false;
}

return true;
6009}

6011/// Evaluate the arguments to a function call.
6012static bool EvaluateArgs(ArrayRef<const Expr *> Args, CallRef Call,
                       EvalInfo &Info, const FunctionDecl *Callee,
                       bool RightToLeft = false) {
bool Success = true;
llvm::SmallBitVector ForbiddenNullArgs;
if (Callee->hasAttr<NonNullAttr>()) {
  ForbiddenNullArgs.resize(Args.size());
  for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) {
    if (!Attr->args_size()) {
      ForbiddenNullArgs.set();
      break;
    } else
      for (auto Idx : Attr->args()) {
        unsigned ASTIdx = Idx.getASTIndex();
        if (ASTIdx >= Args.size())
          continue;
        ForbiddenNullArgs[ASTIdx] = 1;
      }
  }
}
for (unsigned I = 0; I < Args.size(); I++) {
  unsigned Idx = RightToLeft ? Args.size() - I - 1 : I;
  const ParmVarDecl *PVD =
      Idx < Callee->getNumParams() ? Callee->getParamDecl(Idx) : nullptr;
  bool NonNull = !ForbiddenNullArgs.empty() && ForbiddenNullArgs[Idx];
  if (!EvaluateCallArg(PVD, Args[Idx], Call, Info, NonNull)) {
    // If we're checking for a potential constant expression, evaluate all
    // initializers even if some of them fail.
    if (!Info.noteFailure())
      return false;
    Success = false;
  }
}
return Success;
6046}

6048/// Perform a trivial copy from Param, which is the parameter of a copy or move
6049/// constructor or assignment operator.
6050static bool handleTrivialCopy(EvalInfo &Info, const ParmVarDecl *Param,
                            const Expr *E, APValue &Result,
                            bool CopyObjectRepresentation) {
// Find the reference argument.
CallStackFrame *Frame = Info.CurrentCall;
APValue *RefValue = Info.getParamSlot(Frame->Arguments, Param);
57
←
Calling 'EvalInfo::getParamSlot'→
65
←
Returning from 'EvalInfo::getParamSlot'→
if (!RefValue) {
66
←
Assuming 'RefValue' is non-null→
67
←
Taking false branch→
  Info.FFDiag(E);
  return false;
}

// Copy out the contents of the RHS object.
LValue RefLValue;
RefLValue.setFrom(Info.Ctx, *RefValue);
return handleLValueToRValueConversion(
68
←
Calling 'handleLValueToRValueConversion'→
84
←
Returning from 'handleLValueToRValueConversion'→
85
←
Returning value, which participates in a condition later→
    Info, E, Param->getType().getNonReferenceType(), RefLValue, Result,
    CopyObjectRepresentation);
6067}

6069/// Evaluate a function call.
6070static bool HandleFunctionCall(SourceLocation CallLoc,
                             const FunctionDecl *Callee, const LValue *This,
                             ArrayRef<const Expr *> Args, CallRef Call,
                             const Stmt *Body, EvalInfo &Info,
                             APValue &Result, const LValue *ResultSlot) {
if (!Info.CheckCallLimit(CallLoc))
17
←
Calling 'EvalInfo::CheckCallLimit'→
28
←
Returning from 'EvalInfo::CheckCallLimit'→
29
←
Taking false branch→
  return false;

CallStackFrame Frame(Info, CallLoc, Callee, This, Call);

// For a trivial copy or move assignment, perform an APValue copy. This is
// essential for unions, where the operations performed by the assignment
// operator cannot be represented as statements.
//
// Skip this for non-union classes with no fields; in that case, the defaulted
// copy/move does not actually read the object.
const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
30
←
'Callee' is a 'CXXMethodDecl'→
if (MD30.1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
 && MD->isDefaulted() &&
31
←
Assuming the condition is true→
55
←
Taking true branch→
    (MD->getParent()->isUnion() ||
32
←
Calling 'TagDecl::isUnion'→
35
←
Returning from 'TagDecl::isUnion'→
     (MD->isTrivial() &&
36
←
Assuming the condition is true→
      isReadByLvalueToRvalueConversion(MD->getParent())))) {
37
←
Calling 'isReadByLvalueToRvalueConversion'→
54
←
Returning from 'isReadByLvalueToRvalueConversion'→
  assert(This &&((void)0)
         (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()))((void)0);
  APValue RHSValue;
  if (!handleTrivialCopy(Info, MD->getParamDecl(0), Args[0], RHSValue,
56
←
Calling 'handleTrivialCopy'→
86
←
Returning from 'handleTrivialCopy'→
87
←
Assuming the condition is false→
88
←
Taking false branch→
                         MD->getParent()->isUnion()))
    return false;
  if (Info.getLangOpts().CPlusPlus20 && MD->isTrivial() &&
89
←
Assuming field 'CPlusPlus20' is not equal to 0→
      !HandleUnionActiveMemberChange(Info, Args[0], *This))
90
←
Passing value via 2nd parameter 'LHSExpr'→
91
←
Calling 'HandleUnionActiveMemberChange'→
    return false;
  if (!handleAssignment(Info, Args[0], *This, MD->getThisType(),
                        RHSValue))
    return false;
  This->moveInto(Result);
  return true;
} else if (MD && isLambdaCallOperator(MD)) {
  // We're in a lambda; determine the lambda capture field maps unless we're
  // just constexpr checking a lambda's call operator. constexpr checking is
  // done before the captures have been added to the closure object (unless
  // we're inferring constexpr-ness), so we don't have access to them in this
  // case. But since we don't need the captures to constexpr check, we can
  // just ignore them.
  if (!Info.checkingPotentialConstantExpression())
    MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields,
                                      Frame.LambdaThisCaptureField);
}

StmtResult Ret = {Result, ResultSlot};
EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
if (ESR == ESR_Succeeded) {
  if (Callee->getReturnType()->isVoidType())
    return true;
  Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return);
}
return ESR == ESR_Returned;
6125}

6127/// Evaluate a constructor call.
6128static bool HandleConstructorCall(const Expr *E, const LValue &This,
                                CallRef Call,
                                const CXXConstructorDecl *Definition,
                                EvalInfo &Info, APValue &Result) {
SourceLocation CallLoc = E->getExprLoc();
if (!Info.CheckCallLimit(CallLoc))
  return false;

const CXXRecordDecl *RD = Definition->getParent();
if (RD->getNumVBases()) {
  Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
  return false;
}

EvalInfo::EvaluatingConstructorRAII EvalObj(
    Info,
    ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
    RD->getNumBases());
CallStackFrame Frame(Info, CallLoc, Definition, &This, Call);

// FIXME: Creating an APValue just to hold a nonexistent return value is
// wasteful.
APValue RetVal;
StmtResult Ret = {RetVal, nullptr};

// If it's a delegating constructor, delegate.
if (Definition->isDelegatingConstructor()) {
  CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
  if ((*I)->getInit()->isValueDependent()) {
    if (!EvaluateDependentExpr((*I)->getInit(), Info))
      return false;
  } else {
    FullExpressionRAII InitScope(Info);
    if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()) ||
        !InitScope.destroy())
      return false;
  }
  return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
}

// For a trivial copy or move constructor, perform an APValue copy. This is
// essential for unions (or classes with anonymous union members), where the
// operations performed by the constructor cannot be represented by
// ctor-initializers.
//
// Skip this for empty non-union classes; we should not perform an
// lvalue-to-rvalue conversion on them because their copy constructor does not
// actually read them.
if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
    (Definition->getParent()->isUnion() ||
     (Definition->isTrivial() &&
      isReadByLvalueToRvalueConversion(Definition->getParent())))) {
  return handleTrivialCopy(Info, Definition->getParamDecl(0), E, Result,
                           Definition->getParent()->isUnion());
}

// Reserve space for the struct members.
if (!Result.hasValue()) {
  if (!RD->isUnion())
    Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
                     std::distance(RD->field_begin(), RD->field_end()));
  else
    // A union starts with no active member.
    Result = APValue((const FieldDecl*)nullptr);
}

if (RD->isInvalidDecl()) return false;
const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);

// A scope for temporaries lifetime-extended by reference members.
BlockScopeRAII LifetimeExtendedScope(Info);

bool Success = true;
unsigned BasesSeen = 0;
6202#ifndef NDEBUG1
CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
6204#endif
CXXRecordDecl::field_iterator FieldIt = RD->field_begin();
auto SkipToField = [&](FieldDecl *FD, bool Indirect) {
  // We might be initializing the same field again if this is an indirect
  // field initialization.
  if (FieldIt == RD->field_end() ||
      FieldIt->getFieldIndex() > FD->getFieldIndex()) {
    assert(Indirect && "fields out of order?")((void)0);
    return;
  }

  // Default-initialize any fields with no explicit initializer.
  for (; !declaresSameEntity(*FieldIt, FD); ++FieldIt) {
    assert(FieldIt != RD->field_end() && "missing field?")((void)0);
    if (!FieldIt->isUnnamedBitfield())
      Success &= getDefaultInitValue(
          FieldIt->getType(),
          Result.getStructField(FieldIt->getFieldIndex()));
  }
  ++FieldIt;
};
for (const auto *I : Definition->inits()) {
  LValue Subobject = This;
  LValue SubobjectParent = This;
  APValue *Value = &Result;

  // Determine the subobject to initialize.
  FieldDecl *FD = nullptr;
  if (I->isBaseInitializer()) {
    QualType BaseType(I->getBaseClass(), 0);
6234#ifndef NDEBUG1
    // Non-virtual base classes are initialized in the order in the class
    // definition. We have already checked for virtual base classes.
    assert(!BaseIt->isVirtual() && "virtual base for literal type")((void)0);
    assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&((void)0)
           "base class initializers not in expected order")((void)0);
    ++BaseIt;
6241#endif
    if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
                                BaseType->getAsCXXRecordDecl(), &Layout))
      return false;
    Value = &Result.getStructBase(BasesSeen++);
  } else if ((FD = I->getMember())) {
    if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
      return false;
    if (RD->isUnion()) {
      Result = APValue(FD);
      Value = &Result.getUnionValue();
    } else {
      SkipToField(FD, false);
      Value = &Result.getStructField(FD->getFieldIndex());
    }
  } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
    // Walk the indirect field decl's chain to find the object to initialize,
    // and make sure we've initialized every step along it.
    auto IndirectFieldChain = IFD->chain();
    for (auto *C : IndirectFieldChain) {
      FD = cast<FieldDecl>(C);
      CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
      // Switch the union field if it differs. This happens if we had
      // preceding zero-initialization, and we're now initializing a union
      // subobject other than the first.
      // FIXME: In this case, the values of the other subobjects are
      // specified, since zero-initialization sets all padding bits to zero.
      if (!Value->hasValue() ||
          (Value->isUnion() && Value->getUnionField() != FD)) {
        if (CD->isUnion())
          *Value = APValue(FD);
        else
          // FIXME: This immediately starts the lifetime of all members of
          // an anonymous struct. It would be preferable to strictly start
          // member lifetime in initialization order.
          Success &= getDefaultInitValue(Info.Ctx.getRecordType(CD), *Value);
      }
      // Store Subobject as its parent before updating it for the last element
      // in the chain.
      if (C == IndirectFieldChain.back())
        SubobjectParent = Subobject;
      if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
        return false;
      if (CD->isUnion())
        Value = &Value->getUnionValue();
      else {
        if (C == IndirectFieldChain.front() && !RD->isUnion())
          SkipToField(FD, true);
        Value = &Value->getStructField(FD->getFieldIndex());
      }
    }
  } else {
    llvm_unreachable("unknown base initializer kind")__builtin_unreachable();
  }

  // Need to override This for implicit field initializers as in this case
  // This refers to innermost anonymous struct/union containing initializer,
  // not to currently constructed class.
  const Expr *Init = I->getInit();
  if (Init->isValueDependent()) {
    if (!EvaluateDependentExpr(Init, Info))
      return false;
  } else {
    ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent,
                                  isa<CXXDefaultInitExpr>(Init));
    FullExpressionRAII InitScope(Info);
    if (!EvaluateInPlace(*Value, Info, Subobject, Init) ||
        (FD && FD->isBitField() &&
         !truncateBitfieldValue(Info, Init, *Value, FD))) {
      // If we're checking for a potential constant expression, evaluate all
      // initializers even if some of them fail.
      if (!Info.noteFailure())
        return false;
      Success = false;
    }
  }

  // This is the point at which the dynamic type of the object becomes this
  // class type.
  if (I->isBaseInitializer() && BasesSeen == RD->getNumBases())
    EvalObj.finishedConstructingBases();
}

// Default-initialize any remaining fields.
if (!RD->isUnion()) {
  for (; FieldIt != RD->field_end(); ++FieldIt) {
    if (!FieldIt->isUnnamedBitfield())
      Success &= getDefaultInitValue(
          FieldIt->getType(),
          Result.getStructField(FieldIt->getFieldIndex()));
  }
}

EvalObj.finishedConstructingFields();

return Success &&
       EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed &&
       LifetimeExtendedScope.destroy();
6339}

6341static bool HandleConstructorCall(const Expr *E, const LValue &This,
                                ArrayRef<const Expr*> Args,
                                const CXXConstructorDecl *Definition,
                                EvalInfo &Info, APValue &Result) {
CallScopeRAII CallScope(Info);
CallRef Call = Info.CurrentCall->createCall(Definition);
if (!EvaluateArgs(Args, Call, Info, Definition))
  return false;

return HandleConstructorCall(E, This, Call, Definition, Info, Result) &&
       CallScope.destroy();
6352}

6354static bool HandleDestructionImpl(EvalInfo &Info, SourceLocation CallLoc,
                                const LValue &This, APValue &Value,
                                QualType T) {
// Objects can only be destroyed while they're within their lifetimes.
// FIXME: We have no representation for whether an object of type nullptr_t
// is in its lifetime; it usually doesn't matter. Perhaps we should model it
// as indeterminate instead?
if (Value.isAbsent() && !T->isNullPtrType()) {
  APValue Printable;
  This.moveInto(Printable);
  Info.FFDiag(CallLoc, diag::note_constexpr_destroy_out_of_lifetime)
    << Printable.getAsString(Info.Ctx, Info.Ctx.getLValueReferenceType(T));
  return false;
}

// Invent an expression for location purposes.
// FIXME: We shouldn't need to do this.
OpaqueValueExpr LocE(CallLoc, Info.Ctx.IntTy, VK_PRValue);

// For arrays, destroy elements right-to-left.
if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) {
  uint64_t Size = CAT->getSize().getZExtValue();
  QualType ElemT = CAT->getElementType();

  LValue ElemLV = This;
  ElemLV.addArray(Info, &LocE, CAT);
  if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, Size))
    return false;

  // Ensure that we have actual array elements available to destroy; the
  // destructors might mutate the value, so we can't run them on the array
  // filler.
  if (Size && Size > Value.getArrayInitializedElts())
    expandArray(Value, Value.getArraySize() - 1);

  for (; Size != 0; --Size) {
    APValue &Elem = Value.getArrayInitializedElt(Size - 1);
    if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, -1) ||
        !HandleDestructionImpl(Info, CallLoc, ElemLV, Elem, ElemT))
      return false;
  }

  // End the lifetime of this array now.
  Value = APValue();
  return true;
}

const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
if (!RD) {
  if (T.isDestructedType()) {
    Info.FFDiag(CallLoc, diag::note_constexpr_unsupported_destruction) << T;
    return false;
  }

  Value = APValue();
  return true;
}

if (RD->getNumVBases()) {
  Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
  return false;
}

const CXXDestructorDecl *DD = RD->getDestructor();
if (!DD && !RD->hasTrivialDestructor()) {
  Info.FFDiag(CallLoc);
  return false;
}

if (!DD || DD->isTrivial() ||
    (RD->isAnonymousStructOrUnion() && RD->isUnion())) {
  // A trivial destructor just ends the lifetime of the object. Check for
  // this case before checking for a body, because we might not bother
  // building a body for a trivial destructor. Note that it doesn't matter
  // whether the destructor is constexpr in this case; all trivial
  // destructors are constexpr.
  //
  // If an anonymous union would be destroyed, some enclosing destructor must
  // have been explicitly defined, and the anonymous union destruction should
  // have no effect.
  Value = APValue();
  return true;
}

if (!Info.CheckCallLimit(CallLoc))
  return false;

const FunctionDecl *Definition = nullptr;
const Stmt *Body = DD->getBody(Definition);

if (!CheckConstexprFunction(Info, CallLoc, DD, Definition, Body))
  return false;

CallStackFrame Frame(Info, CallLoc, Definition, &This, CallRef());

// We're now in the period of destruction of this object.
unsigned BasesLeft = RD->getNumBases();
EvalInfo::EvaluatingDestructorRAII EvalObj(
    Info,
    ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries});
if (!EvalObj.DidInsert) {
  // C++2a [class.dtor]p19:
  //   the behavior is undefined if the destructor is invoked for an object
  //   whose lifetime has ended
  // (Note that formally the lifetime ends when the period of destruction
  // begins, even though certain uses of the object remain valid until the
  // period of destruction ends.)
  Info.FFDiag(CallLoc, diag::note_constexpr_double_destroy);
  return false;
}

// FIXME: Creating an APValue just to hold a nonexistent return value is
// wasteful.
APValue RetVal;
StmtResult Ret = {RetVal, nullptr};
if (EvaluateStmt(Ret, Info, Definition->getBody()) == ESR_Failed)
  return false;

// A union destructor does not implicitly destroy its members.
if (RD->isUnion())
  return true;

const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);

// We don't have a good way to iterate fields in reverse, so collect all the
// fields first and then walk them backwards.
SmallVector<FieldDecl*, 16> Fields(RD->field_begin(), RD->field_end());
for (const FieldDecl *FD : llvm::reverse(Fields)) {
  if (FD->isUnnamedBitfield())
    continue;

  LValue Subobject = This;
  if (!HandleLValueMember(Info, &LocE, Subobject, FD, &Layout))
    return false;

  APValue *SubobjectValue = &Value.getStructField(FD->getFieldIndex());
  if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
                             FD->getType()))
    return false;
}

if (BasesLeft != 0)
  EvalObj.startedDestroyingBases();

// Destroy base classes in reverse order.
for (const CXXBaseSpecifier &Base : llvm::reverse(RD->bases())) {
  --BasesLeft;

  QualType BaseType = Base.getType();
  LValue Subobject = This;
  if (!HandleLValueDirectBase(Info, &LocE, Subobject, RD,
                              BaseType->getAsCXXRecordDecl(), &Layout))
    return false;

  APValue *SubobjectValue = &Value.getStructBase(BasesLeft);
  if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
                             BaseType))
    return false;
}
assert(BasesLeft == 0 && "NumBases was wrong?")((void)0);

// The period of destruction ends now. The object is gone.
Value = APValue();
return true;
6518}

6520namespace {
6521struct DestroyObjectHandler {
EvalInfo &Info;
const Expr *E;
const LValue &This;
const AccessKinds AccessKind;

typedef bool result_type;
bool failed() { return false; }
bool found(APValue &Subobj, QualType SubobjType) {
  return HandleDestructionImpl(Info, E->getExprLoc(), This, Subobj,
                               SubobjType);
}
bool found(APSInt &Value, QualType SubobjType) {
  Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
  return false;
}
bool found(APFloat &Value, QualType SubobjType) {
  Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
  return false;
}
6541};
6542}

6544/// Perform a destructor or pseudo-destructor call on the given object, which
6545/// might in general not be a complete object.
6546static bool HandleDestruction(EvalInfo &Info, const Expr *E,
                            const LValue &This, QualType ThisType) {
CompleteObject Obj = findCompleteObject(Info, E, AK_Destroy, This, ThisType);
DestroyObjectHandler Handler = {Info, E, This, AK_Destroy};
return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
6551}

6553/// Destroy and end the lifetime of the given complete object.
6554static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
                            APValue::LValueBase LVBase, APValue &Value,
                            QualType T) {
// If we've had an unmodeled side-effect, we can't rely on mutable state
// (such as the object we're about to destroy) being correct.
if (Info.EvalStatus.HasSideEffects)
  return false;

LValue LV;
LV.set({LVBase});
return HandleDestructionImpl(Info, Loc, LV, Value, T);
6565}

6567/// Perform a call to 'perator new' or to `__builtin_operator_new'.
6568static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E,
                                LValue &Result) {
if (Info.checkingPotentialConstantExpression() ||
    Info.SpeculativeEvaluationDepth)
  return false;

// This is permitted only within a call to std::allocator<T>::allocate.
auto Caller = Info.getStdAllocatorCaller("allocate");
if (!Caller) {
  Info.FFDiag(E->getExprLoc(), Info.getLangOpts().CPlusPlus20
                                   ? diag::note_constexpr_new_untyped
                                   : diag::note_constexpr_new);
  return false;
}

QualType ElemType = Caller.ElemType;
if (ElemType->isIncompleteType() || ElemType->isFunctionType()) {
  Info.FFDiag(E->getExprLoc(),
              diag::note_constexpr_new_not_complete_object_type)
      << (ElemType->isIncompleteType() ? 0 : 1) << ElemType;
  return false;
}

APSInt ByteSize;
if (!EvaluateInteger(E->getArg(0), ByteSize, Info))
  return false;
bool IsNothrow = false;
for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) {
  EvaluateIgnoredValue(Info, E->getArg(I));
  IsNothrow |= E->getType()->isNothrowT();
}

CharUnits ElemSize;
if (!HandleSizeof(Info, E->getExprLoc(), ElemType, ElemSize))
  return false;
APInt Size, Remainder;
APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity());
APInt::udivrem(ByteSize, ElemSizeAP, Size, Remainder);
if (Remainder != 0) {
  // This likely indicates a bug in the implementation of 'std::allocator'.
  Info.FFDiag(E->getExprLoc(), diag::note_constexpr_operator_new_bad_size)
      << ByteSize << APSInt(ElemSizeAP, true) << ElemType;
  return false;
}

if (ByteSize.getActiveBits() > ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
  if (IsNothrow) {
    Result.setNull(Info.Ctx, E->getType());
    return true;
  }

  Info.FFDiag(E, diag::note_constexpr_new_too_large) << APSInt(Size, true);
  return false;
}

QualType AllocType = Info.Ctx.getConstantArrayType(ElemType, Size, nullptr,
                                                   ArrayType::Normal, 0);
APValue *Val = Info.createHeapAlloc(E, AllocType, Result);
*Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue());
Result.addArray(Info, E, cast<ConstantArrayType>(AllocType));
return true;
6629}

6631static bool hasVirtualDestructor(QualType T) {
if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
  if (CXXDestructorDecl *DD = RD->getDestructor())
    return DD->isVirtual();
return false;
6636}

6638static const FunctionDecl *getVirtualOperatorDelete(QualType T) {
if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
  if (CXXDestructorDecl *DD = RD->getDestructor())
    return DD->isVirtual() ? DD->getOperatorDelete() : nullptr;
return nullptr;
6643}

6645/// Check that the given object is a suitable pointer to a heap allocation that
6646/// still exists and is of the right kind for the purpose of a deletion.
6647///
6648/// On success, returns the heap allocation to deallocate. On failure, produces
6649/// a diagnostic and returns None.
6650static Optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E,
                                          const LValue &Pointer,
                                          DynAlloc::Kind DeallocKind) {
auto PointerAsString = [&] {
  return Pointer.toString(Info.Ctx, Info.Ctx.VoidPtrTy);
};

DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>();
if (!DA) {
  Info.FFDiag(E, diag::note_constexpr_delete_not_heap_alloc)
      << PointerAsString();
  if (Pointer.Base)
    NoteLValueLocation(Info, Pointer.Base);
  return None;
}

Optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
if (!Alloc) {
  Info.FFDiag(E, diag::note_constexpr_double_delete);
  return None;
}

QualType AllocType = Pointer.Base.getDynamicAllocType();
if (DeallocKind != (*Alloc)->getKind()) {
  Info.FFDiag(E, diag::note_constexpr_new_delete_mismatch)
      << DeallocKind << (*Alloc)->getKind() << AllocType;
  NoteLValueLocation(Info, Pointer.Base);
  return None;
}

bool Subobject = false;
if (DeallocKind == DynAlloc::New) {
  Subobject = Pointer.Designator.MostDerivedPathLength != 0 ||
              Pointer.Designator.isOnePastTheEnd();
} else {
  Subobject = Pointer.Designator.Entries.size() != 1 ||
              Pointer.Designator.Entries[0].getAsArrayIndex() != 0;
}
if (Subobject) {
  Info.FFDiag(E, diag::note_constexpr_delete_subobject)
      << PointerAsString() << Pointer.Designator.isOnePastTheEnd();
  return None;
}

return Alloc;
6695}

6697// Perform a call to 'operator delete' or '__builtin_operator_delete'.
6698bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) {
if (Info.checkingPotentialConstantExpression() ||
    Info.SpeculativeEvaluationDepth)
  return false;

// This is permitted only within a call to std::allocator<T>::deallocate.
if (!Info.getStdAllocatorCaller("deallocate")) {
  Info.FFDiag(E->getExprLoc());
  return true;
}

LValue Pointer;
if (!EvaluatePointer(E->getArg(0), Pointer, Info))
  return false;
for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I)
  EvaluateIgnoredValue(Info, E->getArg(I));

if (Pointer.Designator.Invalid)
  return false;

// Deleting a null pointer would have no effect, but it's not permitted by
// std::allocator<T>::deallocate's contract.
if (Pointer.isNullPointer()) {
  Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_deallocate_null);
  return true;
}

if (!CheckDeleteKind(Info, E, Pointer, DynAlloc::StdAllocator))
  return false;

Info.HeapAllocs.erase(Pointer.Base.get<DynamicAllocLValue>());
return true;
6730}

6732//===----------------------------------------------------------------------===//
6733// Generic Evaluation
6734//===----------------------------------------------------------------------===//
6735namespace {

6737class BitCastBuffer {
// FIXME: We're going to need bit-level granularity when we support
// bit-fields.
// FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but
// we don't support a host or target where that is the case. Still, we should
// use a more generic type in case we ever do.
SmallVector<Optional<unsigned char>, 32> Bytes;

static_assert(std::numeric_limits<unsigned char>::digits >= 8,
              "Need at least 8 bit unsigned char");

bool TargetIsLittleEndian;

6750public:
BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian)
    : Bytes(Width.getQuantity()),
      TargetIsLittleEndian(TargetIsLittleEndian) {}

LLVM_NODISCARD[[clang::warn_unused_result]]
bool readObject(CharUnits Offset, CharUnits Width,
                SmallVectorImpl<unsigned char> &Output) const {
  for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) {
    // If a byte of an integer is uninitialized, then the whole integer is
    // uninitalized.
    if (!Bytes[I.getQuantity()])
      return false;
    Output.push_back(*Bytes[I.getQuantity()]);
  }
  if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
    std::reverse(Output.begin(), Output.end());
  return true;
}

void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) {
  if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
    std::reverse(Input.begin(), Input.end());

  size_t Index = 0;
  for (unsigned char Byte : Input) {
    assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?")((void)0);
    Bytes[Offset.getQuantity() + Index] = Byte;
    ++Index;
  }
}

size_t size() { return Bytes.size(); }
6783};

6785/// Traverse an APValue to produce an BitCastBuffer, emulating how the current
6786/// target would represent the value at runtime.
6787class APValueToBufferConverter {
EvalInfo &Info;
BitCastBuffer Buffer;
const CastExpr *BCE;

APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth,
                         const CastExpr *BCE)
    : Info(Info),
      Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()),
      BCE(BCE) {}

bool visit(const APValue &Val, QualType Ty) {
  return visit(Val, Ty, CharUnits::fromQuantity(0));
}

// Write out Val with type Ty into Buffer starting at Offset.
bool visit(const APValue &Val, QualType Ty, CharUnits Offset) {
  assert((size_t)Offset.getQuantity() <= Buffer.size())((void)0);

  // As a special case, nullptr_t has an indeterminate value.
  if (Ty->isNullPtrType())
    return true;

  // Dig through Src to find the byte at SrcOffset.
  switch (Val.getKind()) {
  case APValue::Indeterminate:
  case APValue::None:
    return true;

  case APValue::Int:
    return visitInt(Val.getInt(), Ty, Offset);
  case APValue::Float:
    return visitFloat(Val.getFloat(), Ty, Offset);
  case APValue::Array:
    return visitArray(Val, Ty, Offset);
  case APValue::Struct:
    return visitRecord(Val, Ty, Offset);

  case APValue::ComplexInt:
  case APValue::ComplexFloat:
  case APValue::Vector:
  case APValue::FixedPoint:
    // FIXME: We should support these.

  case APValue::Union:
  case APValue::MemberPointer:
  case APValue::AddrLabelDiff: {
    Info.FFDiag(BCE->getBeginLoc(),
                diag::note_constexpr_bit_cast_unsupported_type)
        << Ty;
    return false;
  }

  case APValue::LValue:
    llvm_unreachable("LValue subobject in bit_cast?")__builtin_unreachable();
  }
  llvm_unreachable("Unhandled APValue::ValueKind")__builtin_unreachable();
}

bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) {
  const RecordDecl *RD = Ty->getAsRecordDecl();
  const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);

  // Visit the base classes.
  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
    for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
      const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
      CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();

      if (!visitRecord(Val.getStructBase(I), BS.getType(),
                       Layout.getBaseClassOffset(BaseDecl) + Offset))
        return false;
    }
  }

  // Visit the fields.
  unsigned FieldIdx = 0;
  for (FieldDecl *FD : RD->fields()) {
    if (FD->isBitField()) {
      Info.FFDiag(BCE->getBeginLoc(),
                  diag::note_constexpr_bit_cast_unsupported_bitfield);
      return false;
    }

    uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);

    assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 &&((void)0)
           "only bit-fields can have sub-char alignment")((void)0);
    CharUnits FieldOffset =
        Info.Ctx.toCharUnitsFromBits(FieldOffsetBits) + Offset;
    QualType FieldTy = FD->getType();
    if (!visit(Val.getStructField(FieldIdx), FieldTy, FieldOffset))
      return false;
    ++FieldIdx;
  }

  return true;
}

bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) {
  const auto *CAT =
      dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe());
  if (!CAT)
    return false;

  CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType());
  unsigned NumInitializedElts = Val.getArrayInitializedElts();
  unsigned ArraySize = Val.getArraySize();
  // First, initialize the initialized elements.
  for (unsigned I = 0; I != NumInitializedElts; ++I) {
    const APValue &SubObj = Val.getArrayInitializedElt(I);
    if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth))
      return false;
  }

  // Next, initialize the rest of the array using the filler.
  if (Val.hasArrayFiller()) {
    const APValue &Filler = Val.getArrayFiller();
    for (unsigned I = NumInitializedElts; I != ArraySize; ++I) {
      if (!visit(Filler, CAT->getElementType(), Offset + I * ElemWidth))
        return false;
    }
  }

  return true;
}

bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) {
  APSInt AdjustedVal = Val;
  unsigned Width = AdjustedVal.getBitWidth();
  if (Ty->isBooleanType()) {
    Width = Info.Ctx.getTypeSize(Ty);
    AdjustedVal = AdjustedVal.extend(Width);
  }

  SmallVector<unsigned char, 8> Bytes(Width / 8);
  llvm::StoreIntToMemory(AdjustedVal, &*Bytes.begin(), Width / 8);
  Buffer.writeObject(Offset, Bytes);
  return true;
}

bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) {
  APSInt AsInt(Val.bitcastToAPInt());
  return visitInt(AsInt, Ty, Offset);
}

6933public:
static Optional<BitCastBuffer> convert(EvalInfo &Info, const APValue &Src,
                                       const CastExpr *BCE) {
  CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType());
  APValueToBufferConverter Converter(Info, DstSize, BCE);
  if (!Converter.visit(Src, BCE->getSubExpr()->getType()))
    return None;
  return Converter.Buffer;
}
6942};

6944/// Write an BitCastBuffer into an APValue.
6945class BufferToAPValueConverter {
EvalInfo &Info;
const BitCastBuffer &Buffer;
const CastExpr *BCE;

BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer,
                         const CastExpr *BCE)
    : Info(Info), Buffer(Buffer), BCE(BCE) {}

// Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast
// with an invalid type, so anything left is a deficiency on our part (FIXME).
// Ideally this will be unreachable.
llvm::NoneType unsupportedType(QualType Ty) {
  Info.FFDiag(BCE->getBeginLoc(),
              diag::note_constexpr_bit_cast_unsupported_type)
      << Ty;
  return None;
}

llvm::NoneType unrepresentableValue(QualType Ty, const APSInt &Val) {
  Info.FFDiag(BCE->getBeginLoc(),
              diag::note_constexpr_bit_cast_unrepresentable_value)
      << Ty << toString(Val, /*Radix=*/10);
  return None;
}

Optional<APValue> visit(const BuiltinType *T, CharUnits Offset,
                        const EnumType *EnumSugar = nullptr) {
  if (T->isNullPtrType()) {
    uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QualType(T, 0));
    return APValue((Expr *)nullptr,
                   /*Offset=*/CharUnits::fromQuantity(NullValue),
                   APValue::NoLValuePath{}, /*IsNullPtr=*/true);
  }

  CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T);

  // Work around floating point types that contain unused padding bytes. This
  // is really just `long double` on x86, which is the only fundamental type
  // with padding bytes.
  if (T->isRealFloatingType()) {
    const llvm::fltSemantics &Semantics =
        Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
    unsigned NumBits = llvm::APFloatBase::getSizeInBits(Semantics);
    assert(NumBits % 8 == 0)((void)0);
    CharUnits NumBytes = CharUnits::fromQuantity(NumBits / 8);
    if (NumBytes != SizeOf)
      SizeOf = NumBytes;
  }

  SmallVector<uint8_t, 8> Bytes;
  if (!Buffer.readObject(Offset, SizeOf, Bytes)) {
    // If this is std::byte or unsigned char, then its okay to store an
    // indeterminate value.
    bool IsStdByte = EnumSugar && EnumSugar->isStdByteType();
    bool IsUChar =
        !EnumSugar && (T->isSpecificBuiltinType(BuiltinType::UChar) ||
                       T->isSpecificBuiltinType(BuiltinType::Char_U));
    if (!IsStdByte && !IsUChar) {
      QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0);
      Info.FFDiag(BCE->getExprLoc(),
                  diag::note_constexpr_bit_cast_indet_dest)
          << DisplayType << Info.Ctx.getLangOpts().CharIsSigned;
      return None;
    }

    return APValue::IndeterminateValue();
  }

  APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true);
  llvm::LoadIntFromMemory(Val, &*Bytes.begin(), Bytes.size());

  if (T->isIntegralOrEnumerationType()) {
    Val.setIsSigned(T->isSignedIntegerOrEnumerationType());

    unsigned IntWidth = Info.Ctx.getIntWidth(QualType(T, 0));
    if (IntWidth != Val.getBitWidth()) {
      APSInt Truncated = Val.trunc(IntWidth);
      if (Truncated.extend(Val.getBitWidth()) != Val)
        return unrepresentableValue(QualType(T, 0), Val);
      Val = Truncated;
    }

    return APValue(Val);
  }

  if (T->isRealFloatingType()) {
    const llvm::fltSemantics &Semantics =
        Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
    return APValue(APFloat(Semantics, Val));
  }

  return unsupportedType(QualType(T, 0));
}

Optional<APValue> visit(const RecordType *RTy, CharUnits Offset) {
  const RecordDecl *RD = RTy->getAsRecordDecl();
  const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);

  unsigned NumBases = 0;
  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
    NumBases = CXXRD->getNumBases();

  APValue ResultVal(APValue::UninitStruct(), NumBases,
                    std::distance(RD->field_begin(), RD->field_end()));

  // Visit the base classes.
  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
    for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
      const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
      CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
      if (BaseDecl->isEmpty() ||
          Info.Ctx.getASTRecordLayout(BaseDecl).getNonVirtualSize().isZero())
        continue;

      Optional<APValue> SubObj = visitType(
          BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset);
      if (!SubObj)
        return None;
      ResultVal.getStructBase(I) = *SubObj;
    }
  }

  // Visit the fields.
  unsigned FieldIdx = 0;
  for (FieldDecl *FD : RD->fields()) {
    // FIXME: We don't currently support bit-fields. A lot of the logic for
    // this is in CodeGen, so we need to factor it around.
    if (FD->isBitField()) {
      Info.FFDiag(BCE->getBeginLoc(),
                  diag::note_constexpr_bit_cast_unsupported_bitfield);
      return None;
    }

    uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
    assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0)((void)0);

    CharUnits FieldOffset =
        CharUnits::fromQuantity(FieldOffsetBits / Info.Ctx.getCharWidth()) +
        Offset;
    QualType FieldTy = FD->getType();
    Optional<APValue> SubObj = visitType(FieldTy, FieldOffset);
    if (!SubObj)
      return None;
    ResultVal.getStructField(FieldIdx) = *SubObj;
    ++FieldIdx;
  }

  return ResultVal;
}

Optional<APValue> visit(const EnumType *Ty, CharUnits Offset) {
  QualType RepresentationType = Ty->getDecl()->getIntegerType();
  assert(!RepresentationType.isNull() &&((void)0)
         "enum forward decl should be caught by Sema")((void)0);
  const auto *AsBuiltin =
      RepresentationType.getCanonicalType()->castAs<BuiltinType>();
  // Recurse into the underlying type. Treat std::byte transparently as
  // unsigned char.
  return visit(AsBuiltin, Offset, /*EnumTy=*/Ty);
}

Optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) {
  size_t Size = Ty->getSize().getLimitedValue();
  CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType());

  APValue ArrayValue(APValue::UninitArray(), Size, Size);
  for (size_t I = 0; I != Size; ++I) {
    Optional<APValue> ElementValue =
        visitType(Ty->getElementType(), Offset + I * ElementWidth);
    if (!ElementValue)
      return None;
    ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue);
  }

  return ArrayValue;
}

Optional<APValue> visit(const Type *Ty, CharUnits Offset) {
  return unsupportedType(QualType(Ty, 0));
}

Optional<APValue> visitType(QualType Ty, CharUnits Offset) {
  QualType Can = Ty.getCanonicalType();

  switch (Can->getTypeClass()) {
7131#define TYPE(Class, Base)                                                      \
case Type::Class:                                                            \
  return visit(cast<Class##Type>(Can.getTypePtr()), Offset);
7134#define ABSTRACT_TYPE(Class, Base)
7135#define NON_CANONICAL_TYPE(Class, Base)                                        \
case Type::Class:                                                            \
  llvm_unreachable("non-canonical type should be impossible!")__builtin_unreachable();
7138#define DEPENDENT_TYPE(Class, Base)                                            \
case Type::Class:                                                            \
  llvm_unreachable(                                                          \__builtin_unreachable()
      "dependent types aren't supported in the constant evaluator!")__builtin_unreachable();
7142#define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base)case Type::Class: __builtin_unreachable();                            \
case Type::Class:                                                            \
  llvm_unreachable("either dependent or not canonical!")__builtin_unreachable();
7145#include "clang/AST/TypeNodes.inc"
  }
  llvm_unreachable("Unhandled Type::TypeClass")__builtin_unreachable();
}

7150public:
// Pull out a full value of type DstType.
static Optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer,
                                 const CastExpr *BCE) {
  BufferToAPValueConverter Converter(Info, Buffer, BCE);
  return Converter.visitType(BCE->getType(), CharUnits::fromQuantity(0));
}
7157};

7159static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
                                               QualType Ty, EvalInfo *Info,
                                               const ASTContext &Ctx,
                                               bool CheckingDest) {
Ty = Ty.getCanonicalType();

auto diag = [&](int Reason) {
  if (Info)
    Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type)
        << CheckingDest << (Reason == 4) << Reason;
  return false;
};
auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) {
  if (Info)
    Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype)
        << NoteTy << Construct << Ty;
  return false;
};

if (Ty->isUnionType())
  return diag(0);
if (Ty->isPointerType())
  return diag(1);
if (Ty->isMemberPointerType())
  return diag(2);
if (Ty.isVolatileQualified())
  return diag(3);

if (RecordDecl *Record = Ty->getAsRecordDecl()) {
  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) {
    for (CXXBaseSpecifier &BS : CXXRD->bases())
      if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx,
                                                CheckingDest))
        return note(1, BS.getType(), BS.getBeginLoc());
  }
  for (FieldDecl *FD : Record->fields()) {
    if (FD->getType()->isReferenceType())
      return diag(4);
    if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx,
                                              CheckingDest))
      return note(0, FD->getType(), FD->getBeginLoc());
  }
}

if (Ty->isArrayType() &&
    !checkBitCastConstexprEligibilityType(Loc, Ctx.getBaseElementType(Ty),
                                          Info, Ctx, CheckingDest))
  return false;

return true;
7209}

7211static bool checkBitCastConstexprEligibility(EvalInfo *Info,
                                           const ASTContext &Ctx,
                                           const CastExpr *BCE) {
bool DestOK = checkBitCastConstexprEligibilityType(
    BCE->getBeginLoc(), BCE->getType(), Info, Ctx, true);
bool SourceOK = DestOK && checkBitCastConstexprEligibilityType(
                              BCE->getBeginLoc(),
                              BCE->getSubExpr()->getType(), Info, Ctx, false);
return SourceOK;
7220}

7222static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
                                      APValue &SourceValue,
                                      const CastExpr *BCE) {
assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&((void)0)
       "no host or target supports non 8-bit chars")((void)0);
assert(SourceValue.isLValue() &&((void)0)
       "LValueToRValueBitcast requires an lvalue operand!")((void)0);

if (!checkBitCastConstexprEligibility(&Info, Info.Ctx, BCE))
  return false;

LValue SourceLValue;
APValue SourceRValue;
SourceLValue.setFrom(Info.Ctx, SourceValue);
if (!handleLValueToRValueConversion(
        Info, BCE, BCE->getSubExpr()->getType().withConst(), SourceLValue,
        SourceRValue, /*WantObjectRepresentation=*/true))
  return false;

// Read out SourceValue into a char buffer.
Optional<BitCastBuffer> Buffer =
    APValueToBufferConverter::convert(Info, SourceRValue, BCE);
if (!Buffer)
  return false;

// Write out the buffer into a new APValue.
Optional<APValue> MaybeDestValue =
    BufferToAPValueConverter::convert(Info, *Buffer, BCE);
if (!MaybeDestValue)
  return false;

DestValue = std::move(*MaybeDestValue);
return true;
7255}

7257template <class Derived>
7258class ExprEvaluatorBase
: public ConstStmtVisitor<Derived, bool> {
7260private:
Derived &getDerived() { return static_cast<Derived&>(*this); }
bool DerivedSuccess(const APValue &V, const Expr *E) {
  return getDerived().Success(V, E);
}
bool DerivedZeroInitialization(const Expr *E) {
  return getDerived().ZeroInitialization(E);
}

// Check whether a conditional operator with a non-constant condition is a
// potential constant expression. If neither arm is a potential constant
// expression, then the conditional operator is not either.
template<typename ConditionalOperator>
void CheckPotentialConstantConditional(const ConditionalOperator *E) {
  assert(Info.checkingPotentialConstantExpression())((void)0);

  // Speculatively evaluate both arms.
  SmallVector<PartialDiagnosticAt, 8> Diag;
  {
    SpeculativeEvaluationRAII Speculate(Info, &Diag);
    StmtVisitorTy::Visit(E->getFalseExpr());
    if (Diag.empty())
      return;
  }

  {
    SpeculativeEvaluationRAII Speculate(Info, &Diag);
    Diag.clear();
    StmtVisitorTy::Visit(E->getTrueExpr());
    if (Diag.empty())
      return;
  }

  Error(E, diag::note_constexpr_conditional_never_const);
}


template<typename ConditionalOperator>
bool HandleConditionalOperator(const ConditionalOperator *E) {
  bool BoolResult;
  if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
    if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
      CheckPotentialConstantConditional(E);
      return false;
    }
    if (Info.noteFailure()) {
      StmtVisitorTy::Visit(E->getTrueExpr());
      StmtVisitorTy::Visit(E->getFalseExpr());
    }
    return false;
  }

  Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
  return StmtVisitorTy::Visit(EvalExpr);
}

7316protected:
EvalInfo &Info;
typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
typedef ExprEvaluatorBase ExprEvaluatorBaseTy;

OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
  return Info.CCEDiag(E, D);
}

bool ZeroInitialization(const Expr *E) { return Error(E); }

7327public:
ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}

EvalInfo &getEvalInfo() { return Info; }

/// Report an evaluation error. This should only be called when an error is
/// first discovered. When propagating an error, just return false.
bool Error(const Expr *E, diag::kind D) {
  Info.FFDiag(E, D);
  return false;
}
bool Error(const Expr *E) {
  return Error(E, diag::note_invalid_subexpr_in_const_expr);
}

bool VisitStmt(const Stmt *) {
  llvm_unreachable("Expression evaluator should not be called on stmts")__builtin_unreachable();
}
bool VisitExpr(const Expr *E) {
  return Error(E);
}

bool VisitConstantExpr(const ConstantExpr *E) {
  if (E->hasAPValueResult())
    return DerivedSuccess(E->getAPValueResult(), E);

  return StmtVisitorTy::Visit(E->getSubExpr());
}

bool VisitParenExpr(const ParenExpr *E)
  { return StmtVisitorTy::Visit(E->getSubExpr()); }
bool VisitUnaryExtension(const UnaryOperator *E)
  { return StmtVisitorTy::Visit(E->getSubExpr()); }
bool VisitUnaryPlus(const UnaryOperator *E)
  { return StmtVisitorTy::Visit(E->getSubExpr()); }
bool VisitChooseExpr(const ChooseExpr *E)
  { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
  { return StmtVisitorTy::Visit(E->getResultExpr()); }
bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
  { return StmtVisitorTy::Visit(E->getReplacement()); }
bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) {
  TempVersionRAII RAII(*Info.CurrentCall);
  SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
  return StmtVisitorTy::Visit(E->getExpr());
}
bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
  TempVersionRAII RAII(*Info.CurrentCall);
  // The initializer may not have been parsed yet, or might be erroneous.
  if (!E->getExpr())
    return Error(E);
  SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
  return StmtVisitorTy::Visit(E->getExpr());
}

bool VisitExprWithCleanups(const ExprWithCleanups *E) {
  FullExpressionRAII Scope(Info);
  return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy();
}

// Temporaries are registered when created, so we don't care about
// CXXBindTemporaryExpr.
bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
  return StmtVisitorTy::Visit(E->getSubExpr());
}

bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
  CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
  return static_cast<Derived*>(this)->VisitCastExpr(E);
}
bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
  if (!Info.Ctx.getLangOpts().CPlusPlus20)
    CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
  return static_cast<Derived*>(this)->VisitCastExpr(E);
}
bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) {
  return static_cast<Derived*>(this)->VisitCastExpr(E);
}

bool VisitBinaryOperator(const BinaryOperator *E) {
  switch (E->getOpcode()) {
  default:
    return Error(E);

  case BO_Comma:
    VisitIgnoredValue(E->getLHS());
    return StmtVisitorTy::Visit(E->getRHS());

  case BO_PtrMemD:
  case BO_PtrMemI: {
    LValue Obj;
    if (!HandleMemberPointerAccess(Info, E, Obj))
      return false;
    APValue Result;
    if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
      return false;
    return DerivedSuccess(Result, E);
  }
  }
}

bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) {
  return StmtVisitorTy::Visit(E->getSemanticForm());
}

bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
  // Evaluate and cache the common expression. We treat it as a temporary,
  // even though it's not quite the same thing.
  LValue CommonLV;
  if (!Evaluate(Info.CurrentCall->createTemporary(
                    E->getOpaqueValue(),
                    getStorageType(Info.Ctx, E->getOpaqueValue()),
                    ScopeKind::FullExpression, CommonLV),
                Info, E->getCommon()))
    return false;

  return HandleConditionalOperator(E);
}

bool VisitConditionalOperator(const ConditionalOperator *E) {
  bool IsBcpCall = false;
  // If the condition (ignoring parens) is a __builtin_constant_p call,
  // the result is a constant expression if it can be folded without
  // side-effects. This is an important GNU extension. See GCC PR38377
  // for discussion.
  if (const CallExpr *CallCE =
        dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
    if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
      IsBcpCall = true;

  // Always assume __builtin_constant_p(...) ? ... : ... is a potential
  // constant expression; we can't check whether it's potentially foldable.
  // FIXME: We should instead treat __builtin_constant_p as non-constant if
  // it would return 'false' in this mode.
  if (Info.checkingPotentialConstantExpression() && IsBcpCall)
    return false;

  FoldConstant Fold(Info, IsBcpCall);
  if (!HandleConditionalOperator(E)) {
    Fold.keepDiagnostics();
    return false;
  }

  return true;
}

bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
  if (APValue *Value = Info.CurrentCall->getCurrentTemporary(E))
    return DerivedSuccess(*Value, E);

  const Expr *Source = E->getSourceExpr();
  if (!Source)
    return Error(E);
  if (Source == E) { // sanity checking.
    assert(0 && "OpaqueValueExpr recursively refers to itself")((void)0);
    return Error(E);
  }
  return StmtVisitorTy::Visit(Source);
}

bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) {
  for (const Expr *SemE : E->semantics()) {
    if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) {
      // FIXME: We can't handle the case where an OpaqueValueExpr is also the
      // result expression: there could be two different LValues that would
      // refer to the same object in that case, and we can't model that.
      if (SemE == E->getResultExpr())
        return Error(E);

      // Unique OVEs get evaluated if and when we encounter them when
      // emitting the rest of the semantic form, rather than eagerly.
      if (OVE->isUnique())
        continue;

      LValue LV;
      if (!Evaluate(Info.CurrentCall->createTemporary(
                        OVE, getStorageType(Info.Ctx, OVE),
                        ScopeKind::FullExpression, LV),
                    Info, OVE->getSourceExpr()))
        return false;
    } else if (SemE == E->getResultExpr()) {
      if (!StmtVisitorTy::Visit(SemE))
        return false;
    } else {
      if (!EvaluateIgnoredValue(Info, SemE))
        return false;
    }
  }
  return true;
}

bool VisitCallExpr(const CallExpr *E) {
  APValue Result;
  if (!handleCallExpr(E, Result, nullptr))
    return false;
  return DerivedSuccess(Result, E);
}

bool handleCallExpr(const CallExpr *E, APValue &Result,
                   const LValue *ResultSlot) {
  CallScopeRAII CallScope(Info);

  const Expr *Callee = E->getCallee()->IgnoreParens();
  QualType CalleeType = Callee->getType();

  const FunctionDecl *FD = nullptr;
  LValue *This = nullptr, ThisVal;
  auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
  bool HasQualifier = false;

  CallRef Call;

  // Extract function decl and 'this' pointer from the callee.
  if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
    const CXXMethodDecl *Member = nullptr;
    if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
      // Explicit bound member calls, such as x.f() or p->g();
      if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
        return false;
      Member = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
      if (!Member)
        return Error(Callee);
      This = &ThisVal;
      HasQualifier = ME->hasQualifier();
    } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
      // Indirect bound member calls ('.*' or '->*').
      const ValueDecl *D =
          HandleMemberPointerAccess(Info, BE, ThisVal, false);
      if (!D)
        return false;
      Member = dyn_cast<CXXMethodDecl>(D);
      if (!Member)
        return Error(Callee);
      This = &ThisVal;
    } else if (const auto *PDE = dyn_cast<CXXPseudoDestructorExpr>(Callee)) {
      if (!Info.getLangOpts().CPlusPlus20)
        Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor);
      return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) &&
             HandleDestruction(Info, PDE, ThisVal, PDE->getDestroyedType());
    } else
      return Error(Callee);
    FD = Member;
  } else if (CalleeType->isFunctionPointerType()) {
    LValue CalleeLV;
    if (!EvaluatePointer(Callee, CalleeLV, Info))
      return false;

    if (!CalleeLV.getLValueOffset().isZero())
      return Error(Callee);
    FD = dyn_cast_or_null<FunctionDecl>(
        CalleeLV.getLValueBase().dyn_cast<const ValueDecl *>());
    if (!FD)
      return Error(Callee);
    // Don't call function pointers which have been cast to some other type.
    // Per DR (no number yet), the caller and callee can differ in noexcept.
    if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
      CalleeType->getPointeeType(), FD->getType())) {
      return Error(E);
    }

    // For an (overloaded) assignment expression, evaluate the RHS before the
    // LHS.
    auto *OCE = dyn_cast<CXXOperatorCallExpr>(E);
    if (OCE && OCE->isAssignmentOp()) {
      assert(Args.size() == 2 && "wrong number of arguments in assignment")((void)0);
      Call = Info.CurrentCall->createCall(FD);
      if (!EvaluateArgs(isa<CXXMethodDecl>(FD) ? Args.slice(1) : Args, Call,
                        Info, FD, /*RightToLeft=*/true))
        return false;
    }

    // Overloaded operator calls to member functions are represented as normal
    // calls with '*this' as the first argument.
    const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
    if (MD && !MD->isStatic()) {
      // FIXME: When selecting an implicit conversion for an overloaded
      // operator delete, we sometimes try to evaluate calls to conversion
      // operators without a 'this' parameter!
      if (Args.empty())
        return Error(E);

      if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
        return false;
      This = &ThisVal;
      Args = Args.slice(1);
    } else if (MD && MD->isLambdaStaticInvoker()) {
      // Map the static invoker for the lambda back to the call operator.
      // Conveniently, we don't have to slice out the 'this' argument (as is
      // being done for the non-static case), since a static member function
      // doesn't have an implicit argument passed in.
      const CXXRecordDecl *ClosureClass = MD->getParent();
      assert(((void)0)
          ClosureClass->captures_begin() == ClosureClass->captures_end() &&((void)0)
          "Number of captures must be zero for conversion to function-ptr")((void)0);

      const CXXMethodDecl *LambdaCallOp =
          ClosureClass->getLambdaCallOperator();

      // Set 'FD', the function that will be called below, to the call
      // operator.  If the closure object represents a generic lambda, find
      // the corresponding specialization of the call operator.

      if (ClosureClass->isGenericLambda()) {
        assert(MD->isFunctionTemplateSpecialization() &&((void)0)
               "A generic lambda's static-invoker function must be a "((void)0)
               "template specialization")((void)0);
        const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
        FunctionTemplateDecl *CallOpTemplate =
            LambdaCallOp->getDescribedFunctionTemplate();
        void *InsertPos = nullptr;
        FunctionDecl *CorrespondingCallOpSpecialization =
            CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
        assert(CorrespondingCallOpSpecialization &&((void)0)
               "We must always have a function call operator specialization "((void)0)
               "that corresponds to our static invoker specialization")((void)0);
        FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
      } else
        FD = LambdaCallOp;
    } else if (FD->isReplaceableGlobalAllocationFunction()) {
      if (FD->getDeclName().getCXXOverloadedOperator() == OO_New ||
          FD->getDeclName().getCXXOverloadedOperator() == OO_Array_New) {
        LValue Ptr;
        if (!HandleOperatorNewCall(Info, E, Ptr))
          return false;
        Ptr.moveInto(Result);
        return CallScope.destroy();
      } else {
        return HandleOperatorDeleteCall(Info, E) && CallScope.destroy();
      }
    }
  } else
    return Error(E);

  // Evaluate the arguments now if we've not already done so.
  if (!Call) {
    Call = Info.CurrentCall->createCall(FD);
    if (!EvaluateArgs(Args, Call, Info, FD))
      return false;
  }

  SmallVector<QualType, 4> CovariantAdjustmentPath;
  if (This) {
    auto *NamedMember = dyn_cast<CXXMethodDecl>(FD);
    if (NamedMember && NamedMember->isVirtual() && !HasQualifier) {
      // Perform virtual dispatch, if necessary.
      FD = HandleVirtualDispatch(Info, E, *This, NamedMember,
                                 CovariantAdjustmentPath);
      if (!FD)
        return false;
    } else {
      // Check that the 'this' pointer points to an object of the right type.
      // FIXME: If this is an assignment operator call, we may need to change
      // the active union member before we check this.
      if (!checkNonVirtualMemberCallThisPointer(Info, E, *This, NamedMember))
        return false;
    }
  }

  // Destructor calls are different enough that they have their own codepath.
  if (auto *DD = dyn_cast<CXXDestructorDecl>(FD)) {
    assert(This && "no 'this' pointer for destructor call")((void)0);
    return HandleDestruction(Info, E, *This,
                             Info.Ctx.getRecordType(DD->getParent())) &&
           CallScope.destroy();
  }

  const FunctionDecl *Definition = nullptr;
  Stmt *Body = FD->getBody(Definition);

  if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
      !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Call,
                          Body, Info, Result, ResultSlot))
    return false;

  if (!CovariantAdjustmentPath.empty() &&
      !HandleCovariantReturnAdjustment(Info, E, Result,
                                       CovariantAdjustmentPath))
    return false;

  return CallScope.destroy();
}

bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
  return StmtVisitorTy::Visit(E->getInitializer());
}
bool VisitInitListExpr(const InitListExpr *E) {
  if (E->getNumInits() == 0)
    return DerivedZeroInitialization(E);
  if (E->getNumInits() == 1)
    return StmtVisitorTy::Visit(E->getInit(0));
  return Error(E);
}
bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
  return DerivedZeroInitialization(E);
}
bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
  return DerivedZeroInitialization(E);
}
bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
  return DerivedZeroInitialization(E);
}

/// A member expression where the object is a prvalue is itself a prvalue.
bool VisitMemberExpr(const MemberExpr *E) {
  assert(!Info.Ctx.getLangOpts().CPlusPlus11 &&((void)0)
         "missing temporary materialization conversion")((void)0);
  assert(!E->isArrow() && "missing call to bound member function?")((void)0);

  APValue Val;
  if (!Evaluate(Val, Info, E->getBase()))
    return false;

  QualType BaseTy = E->getBase()->getType();

  const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
  if (!FD) return Error(E);
  assert(!FD->getType()->isReferenceType() && "prvalue reference?")((void)0);
  assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==((void)0)
         FD->getParent()->getCanonicalDecl() && "record / field mismatch")((void)0);

  // Note: there is no lvalue base here. But this case should only ever
  // happen in C or in C++98, where we cannot be evaluating a constexpr
  // constructor, which is the only case the base matters.
  CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy);
  SubobjectDesignator Designator(BaseTy);
  Designator.addDeclUnchecked(FD);

  APValue Result;
  return extractSubobject(Info, E, Obj, Designator, Result) &&
         DerivedSuccess(Result, E);
}

bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) {
  APValue Val;
  if (!Evaluate(Val, Info, E->getBase()))
    return false;

  if (Val.isVector()) {
    SmallVector<uint32_t, 4> Indices;
    E->getEncodedElementAccess(Indices);
    if (Indices.size() == 1) {
      // Return scalar.
      return DerivedSuccess(Val.getVectorElt(Indices[0]), E);
    } else {
      // Construct new APValue vector.
      SmallVector<APValue, 4> Elts;
      for (unsigned I = 0; I < Indices.size(); ++I) {
        Elts.push_back(Val.getVectorElt(Indices[I]));
      }
      APValue VecResult(Elts.data(), Indices.size());
      return DerivedSuccess(VecResult, E);
    }
  }

  return false;
}

bool VisitCastExpr(const CastExpr *E) {
  switch (E->getCastKind()) {
  default:
    break;

  case CK_AtomicToNonAtomic: {
    APValue AtomicVal;
    // This does not need to be done in place even for class/array types:
    // atomic-to-non-atomic conversion implies copying the object
    // representation.
    if (!Evaluate(AtomicVal, Info, E->getSubExpr()))
      return false;
    return DerivedSuccess(AtomicVal, E);
  }

  case CK_NoOp:
  case CK_UserDefinedConversion:
    return StmtVisitorTy::Visit(E->getSubExpr());

  case CK_LValueToRValue: {
    LValue LVal;
    if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
      return false;
    APValue RVal;
    // Note, we use the subexpression's type in order to retain cv-qualifiers.
    if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
                                        LVal, RVal))
      return false;
    return DerivedSuccess(RVal, E);
  }
  case CK_LValueToRValueBitCast: {
    APValue DestValue, SourceValue;
    if (!Evaluate(SourceValue, Info, E->getSubExpr()))
      return false;
    if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, E))
      return false;
    return DerivedSuccess(DestValue, E);
  }

  case CK_AddressSpaceConversion: {
    APValue Value;
    if (!Evaluate(Value, Info, E->getSubExpr()))
      return false;
    return DerivedSuccess(Value, E);
  }
  }

  return Error(E);
}

bool VisitUnaryPostInc(const UnaryOperator *UO) {
  return VisitUnaryPostIncDec(UO);
}
bool VisitUnaryPostDec(const UnaryOperator *UO) {
  return VisitUnaryPostIncDec(UO);
}
bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
  if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
    return Error(UO);

  LValue LVal;
  if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
    return false;
  APValue RVal;
  if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
                    UO->isIncrementOp(), &RVal))
    return false;
  return DerivedSuccess(RVal, UO);
}

bool VisitStmtExpr(const StmtExpr *E) {
  // We will have checked the full-expressions inside the statement expression
  // when they were completed, and don't need to check them again now.
  llvm::SaveAndRestore<bool> NotCheckingForUB(
      Info.CheckingForUndefinedBehavior, false);

  const CompoundStmt *CS = E->getSubStmt();
  if (CS->body_empty())
    return true;

  BlockScopeRAII Scope(Info);
  for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
                                         BE = CS->body_end();
       /**/; ++BI) {
    if (BI + 1 == BE) {
      const Expr *FinalExpr = dyn_cast<Expr>(*BI);
      if (!FinalExpr) {
        Info.FFDiag((*BI)->getBeginLoc(),
                    diag::note_constexpr_stmt_expr_unsupported);
        return false;
      }
      return this->Visit(FinalExpr) && Scope.destroy();
    }

    APValue ReturnValue;
    StmtResult Result = { ReturnValue, nullptr };
    EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
    if (ESR != ESR_Succeeded) {
      // FIXME: If the statement-expression terminated due to 'return',
      // 'break', or 'continue', it would be nice to propagate that to
      // the outer statement evaluation rather than bailing out.
      if (ESR != ESR_Failed)
        Info.FFDiag((*BI)->getBeginLoc(),
                    diag::note_constexpr_stmt_expr_unsupported);
      return false;
    }
  }

  llvm_unreachable("Return from function from the loop above.")__builtin_unreachable();
}

/// Visit a value which is evaluated, but whose value is ignored.
void VisitIgnoredValue(const Expr *E) {
  EvaluateIgnoredValue(Info, E);
}

/// Potentially visit a MemberExpr's base expression.
void VisitIgnoredBaseExpression(const Expr *E) {
  // While MSVC doesn't evaluate the base expression, it does diagnose the
  // presence of side-effecting behavior.
  if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
    return;
  VisitIgnoredValue(E);
}
7908};

7910} // namespace

7912//===----------------------------------------------------------------------===//
7913// Common base class for lvalue and temporary evaluation.
7914//===----------------------------------------------------------------------===//
7915namespace {
7916template<class Derived>
7917class LValueExprEvaluatorBase
: public ExprEvaluatorBase<Derived> {
7919protected:
LValue &Result;
bool InvalidBaseOK;
typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;

bool Success(APValue::LValueBase B) {
  Result.set(B);
  return true;
}

bool evaluatePointer(const Expr *E, LValue &Result) {
  return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
}

7934public:
LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
    : ExprEvaluatorBaseTy(Info), Result(Result),
      InvalidBaseOK(InvalidBaseOK) {}

bool Success(const APValue &V, const Expr *E) {
  Result.setFrom(this->Info.Ctx, V);
  return true;
}

bool VisitMemberExpr(const MemberExpr *E) {
  // Handle non-static data members.
  QualType BaseTy;
  bool EvalOK;
  if (E->isArrow()) {
    EvalOK = evaluatePointer(E->getBase(), Result);
    BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
  } else if (E->getBase()->isPRValue()) {
    assert(E->getBase()->getType()->isRecordType())((void)0);
    EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
    BaseTy = E->getBase()->getType();
  } else {
    EvalOK = this->Visit(E->getBase());
    BaseTy = E->getBase()->getType();
  }
  if (!EvalOK) {
    if (!InvalidBaseOK)
      return false;
    Result.setInvalid(E);
    return true;
  }

  const ValueDecl *MD = E->getMemberDecl();
  if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
    assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==((void)0)
           FD->getParent()->getCanonicalDecl() && "record / field mismatch")((void)0);
    (void)BaseTy;
    if (!HandleLValueMember(this->Info, E, Result, FD))
      return false;
  } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
    if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
      return false;
  } else
    return this->Error(E);

  if (MD->getType()->isReferenceType()) {
    APValue RefValue;
    if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
                                        RefValue))
      return false;
    return Success(RefValue, E);
  }
  return true;
}

bool VisitBinaryOperator(const BinaryOperator *E) {
  switch (E->getOpcode()) {
  default:
    return ExprEvaluatorBaseTy::VisitBinaryOperator(E);

  case BO_PtrMemD:
  case BO_PtrMemI:
    return HandleMemberPointerAccess(this->Info, E, Result);
  }
}

bool VisitCastExpr(const CastExpr *E) {
  switch (E->getCastKind()) {
  default:
    return ExprEvaluatorBaseTy::VisitCastExpr(E);

  case CK_DerivedToBase:
  case CK_UncheckedDerivedToBase:
    if (!this->Visit(E->getSubExpr()))
      return false;

    // Now figure out the necessary offset to add to the base LV to get from
    // the derived class to the base class.
    return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
                                Result);
  }
}
8016};
8017}

8019//===----------------------------------------------------------------------===//
8020// LValue Evaluation
8021//
8022// This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
8023// function designators (in C), decl references to void objects (in C), and
8024// temporaries (if building with -Wno-address-of-temporary).
8025//
8026// LValue evaluation produces values comprising a base expression of one of the
8027// following types:
8028// - Declarations
8029//  * VarDecl
8030//  * FunctionDecl
8031// - Literals
8032//  * CompoundLiteralExpr in C (and in global scope in C++)
8033//  * StringLiteral
8034//  * PredefinedExpr
8035//  * ObjCStringLiteralExpr
8036//  * ObjCEncodeExpr
8037//  * AddrLabelExpr
8038//  * BlockExpr
8039//  * CallExpr for a MakeStringConstant builtin
8040// - typeid(T) expressions, as TypeInfoLValues
8041// - Locals and temporaries
8042//  * MaterializeTemporaryExpr
8043//  * Any Expr, with a CallIndex indicating the function in which the temporary
8044//    was evaluated, for cases where the MaterializeTemporaryExpr is missing
8045//    from the AST (FIXME).
8046//  * A MaterializeTemporaryExpr that has static storage duration, with no
8047//    CallIndex, for a lifetime-extended temporary.
8048//  * The ConstantExpr that is currently being evaluated during evaluation of an
8049//    immediate invocation.
8050// plus an offset in bytes.
8051//===----------------------------------------------------------------------===//
8052namespace {
8053class LValueExprEvaluator
: public LValueExprEvaluatorBase<LValueExprEvaluator> {
8055public:
LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
  LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}

bool VisitVarDecl(const Expr *E, const VarDecl *VD);
bool VisitUnaryPreIncDec(const UnaryOperator *UO);

bool VisitDeclRefExpr(const DeclRefExpr *E);
bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
bool VisitMemberExpr(const MemberExpr *E);
bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
bool VisitUnaryDeref(const UnaryOperator *E);
bool VisitUnaryReal(const UnaryOperator *E);
bool VisitUnaryImag(const UnaryOperator *E);
bool VisitUnaryPreInc(const UnaryOperator *UO) {
  return VisitUnaryPreIncDec(UO);
}
bool VisitUnaryPreDec(const UnaryOperator *UO) {
  return VisitUnaryPreIncDec(UO);
}
bool VisitBinAssign(const BinaryOperator *BO);
bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);

bool VisitCastExpr(const CastExpr *E) {
  switch (E->getCastKind()) {
  default:
    return LValueExprEvaluatorBaseTy::VisitCastExpr(E);

  case CK_LValueBitCast:
    this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
    if (!Visit(E->getSubExpr()))
      return false;
    Result.Designator.setInvalid();
    return true;

  case CK_BaseToDerived:
    if (!Visit(E->getSubExpr()))
      return false;
    return HandleBaseToDerivedCast(Info, E, Result);

  case CK_Dynamic:
    if (!Visit(E->getSubExpr()))
      return false;
    return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);
  }
}
8107};
8108} // end anonymous namespace

8110/// Evaluate an expression as an lvalue. This can be legitimately called on
8111/// expressions which are not glvalues, in three cases:
8112///  * function designators in C, and
8113///  * "extern void" objects
8114///  * @selector() expressions in Objective-C
8115static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
                         bool InvalidBaseOK) {
assert(!E->isValueDependent())((void)0);
assert(E->isGLValue() || E->getType()->isFunctionType() ||((void)0)
       E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E))((void)0);
return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8121}

8123bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
const NamedDecl *D = E->getDecl();
if (isa<FunctionDecl, MSGuidDecl, TemplateParamObjectDecl>(D))
  return Success(cast<ValueDecl>(D));
if (const VarDecl *VD = dyn_cast<VarDecl>(D))
  return VisitVarDecl(E, VD);
if (const BindingDecl *BD = dyn_cast<BindingDecl>(D))
  return Visit(BD->getBinding());
return Error(E);
8132}


8135bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {

// If we are within a lambda's call operator, check whether the 'VD' referred
// to within 'E' actually represents a lambda-capture that maps to a
// data-member/field within the closure object, and if so, evaluate to the
// field or what the field refers to.
if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee) &&
    isa<DeclRefExpr>(E) &&
    cast<DeclRefExpr>(E)->refersToEnclosingVariableOrCapture()) {
  // We don't always have a complete capture-map when checking or inferring if
  // the function call operator meets the requirements of a constexpr function
  // - but we don't need to evaluate the captures to determine constexprness
  // (dcl.constexpr C++17).
  if (Info.checkingPotentialConstantExpression())
    return false;

  if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) {
    // Start with 'Result' referring to the complete closure object...
    Result = *Info.CurrentCall->This;
    // ... then update it to refer to the field of the closure object
    // that represents the capture.
    if (!HandleLValueMember(Info, E, Result, FD))
      return false;
    // And if the field is of reference type, update 'Result' to refer to what
    // the field refers to.
    if (FD->getType()->isReferenceType()) {
      APValue RVal;
      if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result,
                                          RVal))
        return false;
      Result.setFrom(Info.Ctx, RVal);
    }
    return true;
  }
}

CallStackFrame *Frame = nullptr;
unsigned Version = 0;
if (VD->hasLocalStorage()) {
  // Only if a local variable was declared in the function currently being
  // evaluated, do we expect to be able to find its value in the current
  // frame. (Otherwise it was likely declared in an enclosing context and
  // could either have a valid evaluatable value (for e.g. a constexpr
  // variable) or be ill-formed (and trigger an appropriate evaluation
  // diagnostic)).
  CallStackFrame *CurrFrame = Info.CurrentCall;
  if (CurrFrame->Callee && CurrFrame->Callee->Equals(VD->getDeclContext())) {
    // Function parameters are stored in some caller's frame. (Usually the
    // immediate caller, but for an inherited constructor they may be more
    // distant.)
    if (auto *PVD = dyn_cast<ParmVarDecl>(VD)) {
      if (CurrFrame->Arguments) {
        VD = CurrFrame->Arguments.getOrigParam(PVD);
        Frame =
            Info.getCallFrameAndDepth(CurrFrame->Arguments.CallIndex).first;
        Version = CurrFrame->Arguments.Version;
      }
    } else {
      Frame = CurrFrame;
      Version = CurrFrame->getCurrentTemporaryVersion(VD);
    }
  }
}

if (!VD->getType()->isReferenceType()) {
  if (Frame) {
    Result.set({VD, Frame->Index, Version});
    return true;
  }
  return Success(VD);
}

if (!Info.getLangOpts().CPlusPlus11) {
  Info.CCEDiag(E, diag::note_constexpr_ltor_non_integral, 1)
      << VD << VD->getType();
  Info.Note(VD->getLocation(), diag::note_declared_at);
}

APValue *V;
if (!evaluateVarDeclInit(Info, E, VD, Frame, Version, V))
  return false;
if (!V->hasValue()) {
  // FIXME: Is it possible for V to be indeterminate here? If so, we should
  // adjust the diagnostic to say that.
  if (!Info.checkingPotentialConstantExpression())
    Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
  return false;
}
return Success(*V, E);
8224}

8226bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
  const MaterializeTemporaryExpr *E) {
// Walk through the expression to find the materialized temporary itself.
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
const Expr *Inner =
    E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);

// If we passed any comma operators, evaluate their LHSs.
for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
  if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
    return false;

// A materialized temporary with static storage duration can appear within the
// result of a constant expression evaluation, so we need to preserve its
// value for use outside this evaluation.
APValue *Value;
if (E->getStorageDuration() == SD_Static) {
  // FIXME: What about SD_Thread?
  Value = E->getOrCreateValue(true);
  *Value = APValue();
  Result.set(E);
} else {
  Value = &Info.CurrentCall->createTemporary(
      E, E->getType(),
      E->getStorageDuration() == SD_FullExpression ? ScopeKind::FullExpression
                                                   : ScopeKind::Block,
      Result);
}

QualType Type = Inner->getType();

// Materialize the temporary itself.
if (!EvaluateInPlace(*Value, Info, Result, Inner)) {
  *Value = APValue();
  return false;
}

// Adjust our lvalue to refer to the desired subobject.
for (unsigned I = Adjustments.size(); I != 0; /**/) {
  --I;
  switch (Adjustments[I].Kind) {
  case SubobjectAdjustment::DerivedToBaseAdjustment:
    if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
                              Type, Result))
      return false;
    Type = Adjustments[I].DerivedToBase.BasePath->getType();
    break;

  case SubobjectAdjustment::FieldAdjustment:
    if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
      return false;
    Type = Adjustments[I].Field->getType();
    break;

  case SubobjectAdjustment::MemberPointerAdjustment:
    if (!HandleMemberPointerAccess(this->Info, Type, Result,
                                   Adjustments[I].Ptr.RHS))
      return false;
    Type = Adjustments[I].Ptr.MPT->getPointeeType();
    break;
  }
}

return true;
8291}

8293bool
8294LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&((void)0)
       "lvalue compound literal in c++?")((void)0);
// Defer visiting the literal until the lvalue-to-rvalue conversion. We can
// only see this when folding in C, so there's no standard to follow here.
return Success(E);
8300}

8302bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
TypeInfoLValue TypeInfo;

if (!E->isPotentiallyEvaluated()) {
  if (E->isTypeOperand())
    TypeInfo = TypeInfoLValue(E->getTypeOperand(Info.Ctx).getTypePtr());
  else
    TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr());
} else {
  if (!Info.Ctx.getLangOpts().CPlusPlus20) {
    Info.CCEDiag(E, diag::note_constexpr_typeid_polymorphic)
      << E->getExprOperand()->getType()
      << E->getExprOperand()->getSourceRange();
  }

  if (!Visit(E->getExprOperand()))
    return false;

  Optional<DynamicType> DynType =
      ComputeDynamicType(Info, E, Result, AK_TypeId);
  if (!DynType)
    return false;

  TypeInfo =
      TypeInfoLValue(Info.Ctx.getRecordType(DynType->Type).getTypePtr());
}

return Success(APValue::LValueBase::getTypeInfo(TypeInfo, E->getType()));
8330}

8332bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
return Success(E->getGuidDecl());
8334}

8336bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
// Handle static data members.
if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
  VisitIgnoredBaseExpression(E->getBase());
  return VisitVarDecl(E, VD);
}

// Handle static member functions.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
  if (MD->isStatic()) {
    VisitIgnoredBaseExpression(E->getBase());
    return Success(MD);
  }
}

// Handle non-static data members.
return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
8353}

8355bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
// FIXME: Deal with vectors as array subscript bases.
if (E->getBase()->getType()->isVectorType())
  return Error(E);

APSInt Index;
bool Success = true;

// C++17's rules require us to evaluate the LHS first, regardless of which
// side is the base.
for (const Expr *SubExpr : {E->getLHS(), E->getRHS()}) {
  if (SubExpr == E->getBase() ? !evaluatePointer(SubExpr, Result)
                              : !EvaluateInteger(SubExpr, Index, Info)) {
    if (!Info.noteFailure())
      return false;
    Success = false;
  }
}

return Success &&
       HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index);
8376}

8378bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
return evaluatePointer(E->getSubExpr(), Result);
8380}

8382bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
if (!Visit(E->getSubExpr()))
  return false;
// __real is a no-op on scalar lvalues.
if (E->getSubExpr()->getType()->isAnyComplexType())
  HandleLValueComplexElement(Info, E, Result, E->getType(), false);
return true;
8389}

8391bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
assert(E->getSubExpr()->getType()->isAnyComplexType() &&((void)0)
       "lvalue __imag__ on scalar?")((void)0);
if (!Visit(E->getSubExpr()))
  return false;
HandleLValueComplexElement(Info, E, Result, E->getType(), true);
return true;
8398}

8400bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
  return Error(UO);

if (!this->Visit(UO->getSubExpr()))
  return false;

return handleIncDec(
    this->Info, UO, Result, UO->getSubExpr()->getType(),
    UO->isIncrementOp(), nullptr);
8410}

8412bool LValueExprEvaluator::VisitCompoundAssignOperator(
  const CompoundAssignOperator *CAO) {
if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
  return Error(CAO);

bool Success = true;

// C++17 onwards require that we evaluate the RHS first.
APValue RHS;
if (!Evaluate(RHS, this->Info, CAO->getRHS())) {
  if (!Info.noteFailure())
    return false;
  Success = false;
}

// The overall lvalue result is the result of evaluating the LHS.
if (!this->Visit(CAO->getLHS()) || !Success)
  return false;

return handleCompoundAssignment(
    this->Info, CAO,
    Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
    CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
8435}

8437bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
  return Error(E);

bool Success = true;

// C++17 onwards require that we evaluate the RHS first.
APValue NewVal;
if (!Evaluate(NewVal, this->Info, E->getRHS())) {
  if (!Info.noteFailure())
    return false;
  Success = false;
}

if (!this->Visit(E->getLHS()) || !Success)
  return false;

if (Info.getLangOpts().CPlusPlus20 &&
    !HandleUnionActiveMemberChange(Info, E->getLHS(), Result))
  return false;

return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
                        NewVal);
8460}

8462//===----------------------------------------------------------------------===//
8463// Pointer Evaluation
8464//===----------------------------------------------------------------------===//

8466/// Attempts to compute the number of bytes available at the pointer
8467/// returned by a function with the alloc_size attribute. Returns true if we
8468/// were successful. Places an unsigned number into `Result`.
8469///
8470/// This expects the given CallExpr to be a call to a function with an
8471/// alloc_size attribute.
8472static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
                                          const CallExpr *Call,
                                          llvm::APInt &Result) {
const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);

assert(AllocSize && AllocSize->getElemSizeParam().isValid())((void)0);
unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
if (Call->getNumArgs() <= SizeArgNo)
  return false;

auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
  Expr::EvalResult ExprResult;
  if (!E->EvaluateAsInt(ExprResult, Ctx, Expr::SE_AllowSideEffects))
    return false;
  Into = ExprResult.Val.getInt();
  if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
    return false;
  Into = Into.zextOrSelf(BitsInSizeT);
  return true;
};

APSInt SizeOfElem;
if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
  return false;

if (!AllocSize->getNumElemsParam().isValid()) {
  Result = std::move(SizeOfElem);
  return true;
}

APSInt NumberOfElems;
unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
  return false;

bool Overflow;
llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
if (Overflow)
  return false;

Result = std::move(BytesAvailable);
return true;
8515}

8517/// Convenience function. LVal's base must be a call to an alloc_size
8518/// function.
8519static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
                                          const LValue &LVal,
                                          llvm::APInt &Result) {
assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&((void)0)
       "Can't get the size of a non alloc_size function")((void)0);
const auto *Base = LVal.getLValueBase().get<const Expr *>();
const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
8527}

8529/// Attempts to evaluate the given LValueBase as the result of a call to
8530/// a function with the alloc_size attribute. If it was possible to do so, this
8531/// function will return true, make Result's Base point to said function call,
8532/// and mark Result's Base as invalid.
8533static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
                                    LValue &Result) {
if (Base.isNull())
  return false;

// Because we do no form of static analysis, we only support const variables.
//
// Additionally, we can't support parameters, nor can we support static
// variables (in the latter case, use-before-assign isn't UB; in the former,
// we have no clue what they'll be assigned to).
const auto *VD =
    dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
  return false;

const Expr *Init = VD->getAnyInitializer();
if (!Init)
  return false;

const Expr *E = Init->IgnoreParens();
if (!tryUnwrapAllocSizeCall(E))
  return false;

// Store E instead of E unwrapped so that the type of the LValue's base is
// what the user wanted.
Result.setInvalid(E);

QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
Result.addUnsizedArray(Info, E, Pointee);
return true;
8563}

8565namespace {
8566class PointerExprEvaluator
: public ExprEvaluatorBase<PointerExprEvaluator> {
LValue &Result;
bool InvalidBaseOK;

bool Success(const Expr *E) {
  Result.set(E);
  return true;
}

bool evaluateLValue(const Expr *E, LValue &Result) {
  return EvaluateLValue(E, Result, Info, InvalidBaseOK);
}

bool evaluatePointer(const Expr *E, LValue &Result) {
  return EvaluatePointer(E, Result, Info, InvalidBaseOK);
}

bool visitNonBuiltinCallExpr(const CallExpr *E);
8585public:

PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
    : ExprEvaluatorBaseTy(info), Result(Result),
      InvalidBaseOK(InvalidBaseOK) {}

bool Success(const APValue &V, const Expr *E) {
  Result.setFrom(Info.Ctx, V);
  return true;
}
bool ZeroInitialization(const Expr *E) {
  Result.setNull(Info.Ctx, E->getType());
  return true;
}

bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitCastExpr(const CastExpr* E);
bool VisitUnaryAddrOf(const UnaryOperator *E);
bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
    { return Success(E); }
bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
  if (E->isExpressibleAsConstantInitializer())
    return Success(E);
  if (Info.noteFailure())
    EvaluateIgnoredValue(Info, E->getSubExpr());
  return Error(E);
}
bool VisitAddrLabelExpr(const AddrLabelExpr *E)
    { return Success(E); }
bool VisitCallExpr(const CallExpr *E);
bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
bool VisitBlockExpr(const BlockExpr *E) {
  if (!E->getBlockDecl()->hasCaptures())
    return Success(E);
  return Error(E);
}
bool VisitCXXThisExpr(const CXXThisExpr *E) {
  // Can't look at 'this' when checking a potential constant expression.
  if (Info.checkingPotentialConstantExpression())
    return false;
  if (!Info.CurrentCall->This) {
    if (Info.getLangOpts().CPlusPlus11)
      Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
    else
      Info.FFDiag(E);
    return false;
  }
  Result = *Info.CurrentCall->This;
  // If we are inside a lambda's call operator, the 'this' expression refers
  // to the enclosing '*this' object (either by value or reference) which is
  // either copied into the closure object's field that represents the '*this'
  // or refers to '*this'.
  if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
    // Ensure we actually have captured 'this'. (an error will have
    // been previously reported if not).
    if (!Info.CurrentCall->LambdaThisCaptureField)
      return false;

    // Update 'Result' to refer to the data member/field of the closure object
    // that represents the '*this' capture.
    if (!HandleLValueMember(Info, E, Result,
                           Info.CurrentCall->LambdaThisCaptureField))
      return false;
    // If we captured '*this' by reference, replace the field with its referent.
    if (Info.CurrentCall->LambdaThisCaptureField->getType()
            ->isPointerType()) {
      APValue RVal;
      if (!handleLValueToRValueConversion(Info, E, E->getType(), Result,
                                          RVal))
        return false;

      Result.setFrom(Info.Ctx, RVal);
    }
  }
  return true;
}

bool VisitCXXNewExpr(const CXXNewExpr *E);

bool VisitSourceLocExpr(const SourceLocExpr *E) {
  assert(E->isStringType() && "SourceLocExpr isn't a pointer type?")((void)0);
  APValue LValResult = E->EvaluateInContext(
      Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
  Result.setFrom(Info.Ctx, LValResult);
  return true;
}

bool VisitSYCLUniqueStableNameExpr(const SYCLUniqueStableNameExpr *E) {
  std::string ResultStr = E->ComputeName(Info.Ctx);

  Info.Ctx.SYCLUniqueStableNameEvaluatedValues[E] = ResultStr;

  QualType CharTy = Info.Ctx.CharTy.withConst();
  APInt Size(Info.Ctx.getTypeSize(Info.Ctx.getSizeType()),
             ResultStr.size() + 1);
  QualType ArrayTy = Info.Ctx.getConstantArrayType(CharTy, Size, nullptr,
                                                   ArrayType::Normal, 0);

  StringLiteral *SL =
      StringLiteral::Create(Info.Ctx, ResultStr, StringLiteral::Ascii,
                            /*Pascal*/ false, ArrayTy, E->getLocation());

  evaluateLValue(SL, Result);
  Result.addArray(Info, E, cast<ConstantArrayType>(ArrayTy));
  return true;
}

// FIXME: Missing: @protocol, @selector
8693};
8694} // end anonymous namespace

8696static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
                          bool InvalidBaseOK) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->hasPointerRepresentation())((void)0);
return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8701}

8703bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->getOpcode() != BO_Add &&
    E->getOpcode() != BO_Sub)
  return ExprEvaluatorBaseTy::VisitBinaryOperator(E);

const Expr *PExp = E->getLHS();
const Expr *IExp = E->getRHS();
if (IExp->getType()->isPointerType())
  std::swap(PExp, IExp);

bool EvalPtrOK = evaluatePointer(PExp, Result);
if (!EvalPtrOK && !Info.noteFailure())
  return false;

llvm::APSInt Offset;
if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
  return false;

if (E->getOpcode() == BO_Sub)
  negateAsSigned(Offset);

QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset);
8726}

8728bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
return evaluateLValue(E->getSubExpr(), Result);
8730}

8732bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
const Expr *SubExpr = E->getSubExpr();

switch (E->getCastKind()) {
default:
  break;
case CK_BitCast:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
case CK_AddressSpaceConversion:
  if (!Visit(SubExpr))
    return false;
  // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
  // permitted in constant expressions in C++11. Bitcasts from cv void* are
  // also static_casts, but we disallow them as a resolution to DR1312.
  if (!E->getType()->isVoidPointerType()) {
    if (!Result.InvalidBase && !Result.Designator.Invalid &&
        !Result.IsNullPtr &&
        Info.Ctx.hasSameUnqualifiedType(Result.Designator.getType(Info.Ctx),
                                        E->getType()->getPointeeType()) &&
        Info.getStdAllocatorCaller("allocate")) {
      // Inside a call to std::allocator::allocate and friends, we permit
      // casting from void* back to cv1 T* for a pointer that points to a
      // cv2 T.
    } else {
      Result.Designator.setInvalid();
      if (SubExpr->getType()->isVoidPointerType())
        CCEDiag(E, diag::note_constexpr_invalid_cast)
          << 3 << SubExpr->getType();
      else
        CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
    }
  }
  if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
    ZeroInitialization(E);
  return true;

case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
  if (!evaluatePointer(E->getSubExpr(), Result))
    return false;
  if (!Result.Base && Result.Offset.isZero())
    return true;

  // Now figure out the necessary offset to add to the base LV to get from
  // the derived class to the base class.
  return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
                                castAs<PointerType>()->getPointeeType(),
                              Result);

case CK_BaseToDerived:
  if (!Visit(E->getSubExpr()))
    return false;
  if (!Result.Base && Result.Offset.isZero())
    return true;
  return HandleBaseToDerivedCast(Info, E, Result);

case CK_Dynamic:
  if (!Visit(E->getSubExpr()))
    return false;
  return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);

case CK_NullToPointer:
  VisitIgnoredValue(E->getSubExpr());
  return ZeroInitialization(E);

case CK_IntegralToPointer: {
  CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;

  APValue Value;
  if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
    break;

  if (Value.isInt()) {
    unsigned Size = Info.Ctx.getTypeSize(E->getType());
    uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
    Result.Base = (Expr*)nullptr;
    Result.InvalidBase = false;
    Result.Offset = CharUnits::fromQuantity(N);
    Result.Designator.setInvalid();
    Result.IsNullPtr = false;
    return true;
  } else {
    // Cast is of an lvalue, no need to change value.
    Result.setFrom(Info.Ctx, Value);
    return true;
  }
}

case CK_ArrayToPointerDecay: {
  if (SubExpr->isGLValue()) {
    if (!evaluateLValue(SubExpr, Result))
      return false;
  } else {
    APValue &Value = Info.CurrentCall->createTemporary(
        SubExpr, SubExpr->getType(), ScopeKind::FullExpression, Result);
    if (!EvaluateInPlace(Value, Info, Result, SubExpr))
      return false;
  }
  // The result is a pointer to the first element of the array.
  auto *AT = Info.Ctx.getAsArrayType(SubExpr->getType());
  if (auto *CAT = dyn_cast<ConstantArrayType>(AT))
    Result.addArray(Info, E, CAT);
  else
    Result.addUnsizedArray(Info, E, AT->getElementType());
  return true;
}

case CK_FunctionToPointerDecay:
  return evaluateLValue(SubExpr, Result);

case CK_LValueToRValue: {
  LValue LVal;
  if (!evaluateLValue(E->getSubExpr(), LVal))
    return false;

  APValue RVal;
  // Note, we use the subexpression's type in order to retain cv-qualifiers.
  if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
                                      LVal, RVal))
    return InvalidBaseOK &&
           evaluateLValueAsAllocSize(Info, LVal.Base, Result);
  return Success(RVal, E);
}
}

return ExprEvaluatorBaseTy::VisitCastExpr(E);
8860}

8862static CharUnits GetAlignOfType(EvalInfo &Info, QualType T,
                              UnaryExprOrTypeTrait ExprKind) {
// C++ [expr.alignof]p3:
//     When alignof is applied to a reference type, the result is the
//     alignment of the referenced type.
if (const ReferenceType *Ref = T->getAs<ReferenceType>())
  T = Ref->getPointeeType();

if (T.getQualifiers().hasUnaligned())
  return CharUnits::One();

const bool AlignOfReturnsPreferred =
    Info.Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7;

// __alignof is defined to return the preferred alignment.
// Before 8, clang returned the preferred alignment for alignof and _Alignof
// as well.
if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred)
  return Info.Ctx.toCharUnitsFromBits(
    Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
// alignof and _Alignof are defined to return the ABI alignment.
else if (ExprKind == UETT_AlignOf)
  return Info.Ctx.getTypeAlignInChars(T.getTypePtr());
else
  llvm_unreachable("GetAlignOfType on a non-alignment ExprKind")__builtin_unreachable();
8887}

8889static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E,
                              UnaryExprOrTypeTrait ExprKind) {
E = E->IgnoreParens();

// The kinds of expressions that we have special-case logic here for
// should be kept up to date with the special checks for those
// expressions in Sema.

// alignof decl is always accepted, even if it doesn't make sense: we default
// to 1 in those cases.
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
  return Info.Ctx.getDeclAlign(DRE->getDecl(),
                               /*RefAsPointee*/true);

if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
  return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
                               /*RefAsPointee*/true);

return GetAlignOfType(Info, E->getType(), ExprKind);
8908}

8910static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) {
if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>())
  return Info.Ctx.getDeclAlign(VD);
if (const auto *E = Value.Base.dyn_cast<const Expr *>())
  return GetAlignOfExpr(Info, E, UETT_AlignOf);
return GetAlignOfType(Info, Value.Base.getTypeInfoType(), UETT_AlignOf);
8916}

8918/// Evaluate the value of the alignment argument to __builtin_align_{up,down},
8919/// __builtin_is_aligned and __builtin_assume_aligned.
8920static bool getAlignmentArgument(const Expr *E, QualType ForType,
                               EvalInfo &Info, APSInt &Alignment) {
if (!EvaluateInteger(E, Alignment, Info))
  return false;
if (Alignment < 0 || !Alignment.isPowerOf2()) {
  Info.FFDiag(E, diag::note_constexpr_invalid_alignment) << Alignment;
  return false;
}
unsigned SrcWidth = Info.Ctx.getIntWidth(ForType);
APSInt MaxValue(APInt::getOneBitSet(SrcWidth, SrcWidth - 1));
if (APSInt::compareValues(Alignment, MaxValue) > 0) {
  Info.FFDiag(E, diag::note_constexpr_alignment_too_big)
      << MaxValue << ForType << Alignment;
  return false;
}
// Ensure both alignment and source value have the same bit width so that we
// don't assert when computing the resulting value.
APSInt ExtAlignment =
    APSInt(Alignment.zextOrTrunc(SrcWidth), /*isUnsigned=*/true);
assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 &&((void)0)
       "Alignment should not be changed by ext/trunc")((void)0);
Alignment = ExtAlignment;
assert(Alignment.getBitWidth() == SrcWidth)((void)0);
return true;
8944}

8946// To be clear: this happily visits unsupported builtins. Better name welcomed.
8947bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
if (ExprEvaluatorBaseTy::VisitCallExpr(E))
  return true;

if (!(InvalidBaseOK && getAllocSizeAttr(E)))
  return false;

Result.setInvalid(E);
QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
Result.addUnsizedArray(Info, E, PointeeTy);
return true;
8958}

8960bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
if (IsStringLiteralCall(E))
  return Success(E);

if (unsigned BuiltinOp = E->getBuiltinCallee())
  return VisitBuiltinCallExpr(E, BuiltinOp);

return visitNonBuiltinCallExpr(E);
8968}

8970// Determine if T is a character type for which we guarantee that
8971// sizeof(T) == 1.
8972static bool isOneByteCharacterType(QualType T) {
return T->isCharType() || T->isChar8Type();
8974}

8976bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
                                              unsigned BuiltinOp) {
switch (BuiltinOp) {
case Builtin::BI__builtin_addressof:
  return evaluateLValue(E->getArg(0), Result);
case Builtin::BI__builtin_assume_aligned: {
  // We need to be very careful here because: if the pointer does not have the
  // asserted alignment, then the behavior is undefined, and undefined
  // behavior is non-constant.
  if (!evaluatePointer(E->getArg(0), Result))
    return false;

  LValue OffsetResult(Result);
  APSInt Alignment;
  if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
                            Alignment))
    return false;
  CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue());

  if (E->getNumArgs() > 2) {
    APSInt Offset;
    if (!EvaluateInteger(E->getArg(2), Offset, Info))
      return false;

    int64_t AdditionalOffset = -Offset.getZExtValue();
    OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
  }

  // If there is a base object, then it must have the correct alignment.
  if (OffsetResult.Base) {
    CharUnits BaseAlignment = getBaseAlignment(Info, OffsetResult);

    if (BaseAlignment < Align) {
      Result.Designator.setInvalid();
      // FIXME: Add support to Diagnostic for long / long long.
      CCEDiag(E->getArg(0),
              diag::note_constexpr_baa_insufficient_alignment) << 0
        << (unsigned)BaseAlignment.getQuantity()
        << (unsigned)Align.getQuantity();
      return false;
    }
  }

  // The offset must also have the correct alignment.
  if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
    Result.Designator.setInvalid();

    (OffsetResult.Base
         ? CCEDiag(E->getArg(0),
                   diag::note_constexpr_baa_insufficient_alignment) << 1
         : CCEDiag(E->getArg(0),
                   diag::note_constexpr_baa_value_insufficient_alignment))
      << (int)OffsetResult.Offset.getQuantity()
      << (unsigned)Align.getQuantity();
    return false;
  }

  return true;
}
case Builtin::BI__builtin_align_up:
case Builtin::BI__builtin_align_down: {
  if (!evaluatePointer(E->getArg(0), Result))
    return false;
  APSInt Alignment;
  if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
                            Alignment))
    return false;
  CharUnits BaseAlignment = getBaseAlignment(Info, Result);
  CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Result.Offset);
  // For align_up/align_down, we can return the same value if the alignment
  // is known to be greater or equal to the requested value.
  if (PtrAlign.getQuantity() >= Alignment)
    return true;

  // The alignment could be greater than the minimum at run-time, so we cannot
  // infer much about the resulting pointer value. One case is possible:
  // For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we
  // can infer the correct index if the requested alignment is smaller than
  // the base alignment so we can perform the computation on the offset.
  if (BaseAlignment.getQuantity() >= Alignment) {
    assert(Alignment.getBitWidth() <= 64 &&((void)0)
           "Cannot handle > 64-bit address-space")((void)0);
    uint64_t Alignment64 = Alignment.getZExtValue();
    CharUnits NewOffset = CharUnits::fromQuantity(
        BuiltinOp == Builtin::BI__builtin_align_down
            ? llvm::alignDown(Result.Offset.getQuantity(), Alignment64)
            : llvm::alignTo(Result.Offset.getQuantity(), Alignment64));
    Result.adjustOffset(NewOffset - Result.Offset);
    // TODO: diagnose out-of-bounds values/only allow for arrays?
    return true;
  }
  // Otherwise, we cannot constant-evaluate the result.
  Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_adjust)
      << Alignment;
  return false;
}
case Builtin::BI__builtin_operator_new:
  return HandleOperatorNewCall(Info, E, Result);
case Builtin::BI__builtin_launder:
  return evaluatePointer(E->getArg(0), Result);
case Builtin::BIstrchr:
case Builtin::BIwcschr:
case Builtin::BImemchr:
case Builtin::BIwmemchr:
  if (Info.getLangOpts().CPlusPlus11)
    Info.CCEDiag(E, diag::note_constexpr_invalid_function)
      << /*isConstexpr*/0 << /*isConstructor*/0
      << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
  else
    Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case Builtin::BI__builtin_strchr:
case Builtin::BI__builtin_wcschr:
case Builtin::BI__builtin_memchr:
case Builtin::BI__builtin_char_memchr:
case Builtin::BI__builtin_wmemchr: {
  if (!Visit(E->getArg(0)))
    return false;
  APSInt Desired;
  if (!EvaluateInteger(E->getArg(1), Desired, Info))
    return false;
  uint64_t MaxLength = uint64_t(-1);
  if (BuiltinOp != Builtin::BIstrchr &&
      BuiltinOp != Builtin::BIwcschr &&
      BuiltinOp != Builtin::BI__builtin_strchr &&
      BuiltinOp != Builtin::BI__builtin_wcschr) {
    APSInt N;
    if (!EvaluateInteger(E->getArg(2), N, Info))
      return false;
    MaxLength = N.getExtValue();
  }
  // We cannot find the value if there are no candidates to match against.
  if (MaxLength == 0u)
    return ZeroInitialization(E);
  if (!Result.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
      Result.Designator.Invalid)
    return false;
  QualType CharTy = Result.Designator.getType(Info.Ctx);
  bool IsRawByte = BuiltinOp == Builtin::BImemchr ||
                   BuiltinOp == Builtin::BI__builtin_memchr;
  assert(IsRawByte ||((void)0)
         Info.Ctx.hasSameUnqualifiedType(((void)0)
             CharTy, E->getArg(0)->getType()->getPointeeType()))((void)0);
  // Pointers to const void may point to objects of incomplete type.
  if (IsRawByte && CharTy->isIncompleteType()) {
    Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << CharTy;
    return false;
  }
  // Give up on byte-oriented matching against multibyte elements.
  // FIXME: We can compare the bytes in the correct order.
  if (IsRawByte && !isOneByteCharacterType(CharTy)) {
    Info.FFDiag(E, diag::note_constexpr_memchr_unsupported)
        << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
        << CharTy;
    return false;
  }
  // Figure out what value we're actually looking for (after converting to
  // the corresponding unsigned type if necessary).
  uint64_t DesiredVal;
  bool StopAtNull = false;
  switch (BuiltinOp) {
  case Builtin::BIstrchr:
  case Builtin::BI__builtin_strchr:
    // strchr compares directly to the passed integer, and therefore
    // always fails if given an int that is not a char.
    if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
                                                E->getArg(1)->getType(),
                                                Desired),
                             Desired))
      return ZeroInitialization(E);
    StopAtNull = true;
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case Builtin::BImemchr:
  case Builtin::BI__builtin_memchr:
  case Builtin::BI__builtin_char_memchr:
    // memchr compares by converting both sides to unsigned char. That's also
    // correct for strchr if we get this far (to cope with plain char being
    // unsigned in the strchr case).
    DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
    break;

  case Builtin::BIwcschr:
  case Builtin::BI__builtin_wcschr:
    StopAtNull = true;
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case Builtin::BIwmemchr:
  case Builtin::BI__builtin_wmemchr:
    // wcschr and wmemchr are given a wchar_t to look for. Just use it.
    DesiredVal = Desired.getZExtValue();
    break;
  }

  for (; MaxLength; --MaxLength) {
    APValue Char;
    if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
        !Char.isInt())
      return false;
    if (Char.getInt().getZExtValue() == DesiredVal)
      return true;
    if (StopAtNull && !Char.getInt())
      break;
    if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
      return false;
  }
  // Not found: return nullptr.
  return ZeroInitialization(E);
}

case Builtin::BImemcpy:
case Builtin::BImemmove:
case Builtin::BIwmemcpy:
case Builtin::BIwmemmove:
  if (Info.getLangOpts().CPlusPlus11)
    Info.CCEDiag(E, diag::note_constexpr_invalid_function)
      << /*isConstexpr*/0 << /*isConstructor*/0
      << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
  else
    Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case Builtin::BI__builtin_memcpy:
case Builtin::BI__builtin_memmove:
case Builtin::BI__builtin_wmemcpy:
case Builtin::BI__builtin_wmemmove: {
  bool WChar = BuiltinOp == Builtin::BIwmemcpy ||
               BuiltinOp == Builtin::BIwmemmove ||
               BuiltinOp == Builtin::BI__builtin_wmemcpy ||
               BuiltinOp == Builtin::BI__builtin_wmemmove;
  bool Move = BuiltinOp == Builtin::BImemmove ||
              BuiltinOp == Builtin::BIwmemmove ||
              BuiltinOp == Builtin::BI__builtin_memmove ||
              BuiltinOp == Builtin::BI__builtin_wmemmove;

  // The result of mem* is the first argument.
  if (!Visit(E->getArg(0)))
    return false;
  LValue Dest = Result;

  LValue Src;
  if (!EvaluatePointer(E->getArg(1), Src, Info))
    return false;

  APSInt N;
  if (!EvaluateInteger(E->getArg(2), N, Info))
    return false;
  assert(!N.isSigned() && "memcpy and friends take an unsigned size")((void)0);

  // If the size is zero, we treat this as always being a valid no-op.
  // (Even if one of the src and dest pointers is null.)
  if (!N)
    return true;

  // Otherwise, if either of the operands is null, we can't proceed. Don't
  // try to determine the type of the copied objects, because there aren't
  // any.
  if (!Src.Base || !Dest.Base) {
    APValue Val;
    (!Src.Base ? Src : Dest).moveInto(Val);
    Info.FFDiag(E, diag::note_constexpr_memcpy_null)
        << Move << WChar << !!Src.Base
        << Val.getAsString(Info.Ctx, E->getArg(0)->getType());
    return false;
  }
  if (Src.Designator.Invalid || Dest.Designator.Invalid)
    return false;

  // We require that Src and Dest are both pointers to arrays of
  // trivially-copyable type. (For the wide version, the designator will be
  // invalid if the designated object is not a wchar_t.)
  QualType T = Dest.Designator.getType(Info.Ctx);
  QualType SrcT = Src.Designator.getType(Info.Ctx);
  if (!Info.Ctx.hasSameUnqualifiedType(T, SrcT)) {
    // FIXME: Consider using our bit_cast implementation to support this.
    Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T;
    return false;
  }
  if (T->isIncompleteType()) {
    Info.FFDiag(E, diag::note_constexpr_memcpy_incomplete_type) << Move << T;
    return false;
  }
  if (!T.isTriviallyCopyableType(Info.Ctx)) {
    Info.FFDiag(E, diag::note_constexpr_memcpy_nontrivial) << Move << T;
    return false;
  }

  // Figure out how many T's we're copying.
  uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity();
  if (!WChar) {
    uint64_t Remainder;
    llvm::APInt OrigN = N;
    llvm::APInt::udivrem(OrigN, TSize, N, Remainder);
    if (Remainder) {
      Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
          << Move << WChar << 0 << T << toString(OrigN, 10, /*Signed*/false)
          << (unsigned)TSize;
      return false;
    }
  }

  // Check that the copying will remain within the arrays, just so that we
  // can give a more meaningful diagnostic. This implicitly also checks that
  // N fits into 64 bits.
  uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second;
  uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second;
  if (N.ugt(RemainingSrcSize) || N.ugt(RemainingDestSize)) {
    Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
        << Move << WChar << (N.ugt(RemainingSrcSize) ? 1 : 2) << T
        << toString(N, 10, /*Signed*/false);
    return false;
  }
  uint64_t NElems = N.getZExtValue();
  uint64_t NBytes = NElems * TSize;

  // Check for overlap.
  int Direction = 1;
  if (HasSameBase(Src, Dest)) {
    uint64_t SrcOffset = Src.getLValueOffset().getQuantity();
    uint64_t DestOffset = Dest.getLValueOffset().getQuantity();
    if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) {
      // Dest is inside the source region.
      if (!Move) {
        Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
        return false;
      }
      // For memmove and friends, copy backwards.
      if (!HandleLValueArrayAdjustment(Info, E, Src, T, NElems - 1) ||
          !HandleLValueArrayAdjustment(Info, E, Dest, T, NElems - 1))
        return false;
      Direction = -1;
    } else if (!Move && SrcOffset >= DestOffset &&
               SrcOffset - DestOffset < NBytes) {
      // Src is inside the destination region for memcpy: invalid.
      Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
      return false;
    }
  }

  while (true) {
    APValue Val;
    // FIXME: Set WantObjectRepresentation to true if we're copying a
    // char-like type?
    if (!handleLValueToRValueConversion(Info, E, T, Src, Val) ||
        !handleAssignment(Info, E, Dest, T, Val))
      return false;
    // Do not iterate past the last element; if we're copying backwards, that
    // might take us off the start of the array.
    if (--NElems == 0)
      return true;
    if (!HandleLValueArrayAdjustment(Info, E, Src, T, Direction) ||
        !HandleLValueArrayAdjustment(Info, E, Dest, T, Direction))
      return false;
  }
}

default:
  break;
}

return visitNonBuiltinCallExpr(E);
9334}

9336static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
                                   APValue &Result, const InitListExpr *ILE,
                                   QualType AllocType);
9339static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
                                        APValue &Result,
                                        const CXXConstructExpr *CCE,
                                        QualType AllocType);

9344bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) {
if (!Info.getLangOpts().CPlusPlus20)
  Info.CCEDiag(E, diag::note_constexpr_new);

// We cannot speculatively evaluate a delete expression.
if (Info.SpeculativeEvaluationDepth)
  return false;

FunctionDecl *OperatorNew = E->getOperatorNew();

bool IsNothrow = false;
bool IsPlacement = false;
if (OperatorNew->isReservedGlobalPlacementOperator() &&
    Info.CurrentCall->isStdFunction() && !E->isArray()) {
  // FIXME Support array placement new.
  assert(E->getNumPlacementArgs() == 1)((void)0);
  if (!EvaluatePointer(E->getPlacementArg(0), Result, Info))
    return false;
  if (Result.Designator.Invalid)
    return false;
  IsPlacement = true;
} else if (!OperatorNew->isReplaceableGlobalAllocationFunction()) {
  Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
      << isa<CXXMethodDecl>(OperatorNew) << OperatorNew;
  return false;
} else if (E->getNumPlacementArgs()) {
  // The only new-placement list we support is of the form (std::nothrow).
  //
  // FIXME: There is no restriction on this, but it's not clear that any
  // other form makes any sense. We get here for cases such as:
  //
  //   new (std::align_val_t{N}) X(int)
  //
  // (which should presumably be valid only if N is a multiple of
  // alignof(int), and in any case can't be deallocated unless N is
  // alignof(X) and X has new-extended alignment).
  if (E->getNumPlacementArgs() != 1 ||
      !E->getPlacementArg(0)->getType()->isNothrowT())
    return Error(E, diag::note_constexpr_new_placement);

  LValue Nothrow;
  if (!EvaluateLValue(E->getPlacementArg(0), Nothrow, Info))
    return false;
  IsNothrow = true;
}

const Expr *Init = E->getInitializer();
const InitListExpr *ResizedArrayILE = nullptr;
const CXXConstructExpr *ResizedArrayCCE = nullptr;
bool ValueInit = false;

QualType AllocType = E->getAllocatedType();
if (Optional<const Expr*> ArraySize = E->getArraySize()) {
  const Expr *Stripped = *ArraySize;
  for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Stripped);
       Stripped = ICE->getSubExpr())
    if (ICE->getCastKind() != CK_NoOp &&
        ICE->getCastKind() != CK_IntegralCast)
      break;

  llvm::APSInt ArrayBound;
  if (!EvaluateInteger(Stripped, ArrayBound, Info))
    return false;

  // C++ [expr.new]p9:
  //   The expression is erroneous if:
  //   -- [...] its value before converting to size_t [or] applying the
  //      second standard conversion sequence is less than zero
  if (ArrayBound.isSigned() && ArrayBound.isNegative()) {
    if (IsNothrow)
      return ZeroInitialization(E);

    Info.FFDiag(*ArraySize, diag::note_constexpr_new_negative)
        << ArrayBound << (*ArraySize)->getSourceRange();
    return false;
  }

  //   -- its value is such that the size of the allocated object would
  //      exceed the implementation-defined limit
  if (ConstantArrayType::getNumAddressingBits(Info.Ctx, AllocType,
                                              ArrayBound) >
      ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
    if (IsNothrow)
      return ZeroInitialization(E);

    Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_large)
      << ArrayBound << (*ArraySize)->getSourceRange();
    return false;
  }

  //   -- the new-initializer is a braced-init-list and the number of
  //      array elements for which initializers are provided [...]
  //      exceeds the number of elements to initialize
  if (!Init) {
    // No initialization is performed.
  } else if (isa<CXXScalarValueInitExpr>(Init) ||
             isa<ImplicitValueInitExpr>(Init)) {
    ValueInit = true;
  } else if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) {
    ResizedArrayCCE = CCE;
  } else {
    auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType());
    assert(CAT && "unexpected type for array initializer")((void)0);

    unsigned Bits =
        std::max(CAT->getSize().getBitWidth(), ArrayBound.getBitWidth());
    llvm::APInt InitBound = CAT->getSize().zextOrSelf(Bits);
    llvm::APInt AllocBound = ArrayBound.zextOrSelf(Bits);
    if (InitBound.ugt(AllocBound)) {
      if (IsNothrow)
        return ZeroInitialization(E);

      Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_small)
          << toString(AllocBound, 10, /*Signed=*/false)
          << toString(InitBound, 10, /*Signed=*/false)
          << (*ArraySize)->getSourceRange();
      return false;
    }

    // If the sizes differ, we must have an initializer list, and we need
    // special handling for this case when we initialize.
    if (InitBound != AllocBound)
      ResizedArrayILE = cast<InitListExpr>(Init);
  }

  AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound, nullptr,
                                            ArrayType::Normal, 0);
} else {
  assert(!AllocType->isArrayType() &&((void)0)
         "array allocation with non-array new")((void)0);
}

APValue *Val;
if (IsPlacement) {
  AccessKinds AK = AK_Construct;
  struct FindObjectHandler {
    EvalInfo &Info;
    const Expr *E;
    QualType AllocType;
    const AccessKinds AccessKind;
    APValue *Value;

    typedef bool result_type;
    bool failed() { return false; }
    bool found(APValue &Subobj, QualType SubobjType) {
      // FIXME: Reject the cases where [basic.life]p8 would not permit the
      // old name of the object to be used to name the new object.
      if (!Info.Ctx.hasSameUnqualifiedType(SubobjType, AllocType)) {
        Info.FFDiag(E, diag::note_constexpr_placement_new_wrong_type) <<
          SubobjType << AllocType;
        return false;
      }
      Value = &Subobj;
      return true;
    }
    bool found(APSInt &Value, QualType SubobjType) {
      Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
      return false;
    }
    bool found(APFloat &Value, QualType SubobjType) {
      Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
      return false;
    }
  } Handler = {Info, E, AllocType, AK, nullptr};

  CompleteObject Obj = findCompleteObject(Info, E, AK, Result, AllocType);
  if (!Obj || !findSubobject(Info, E, Obj, Result.Designator, Handler))
    return false;

  Val = Handler.Value;

  // [basic.life]p1:
  //   The lifetime of an object o of type T ends when [...] the storage
  //   which the object occupies is [...] reused by an object that is not
  //   nested within o (6.6.2).
  *Val = APValue();
} else {
  // Perform the allocation and obtain a pointer to the resulting object.
  Val = Info.createHeapAlloc(E, AllocType, Result);
  if (!Val)
    return false;
}

if (ValueInit) {
  ImplicitValueInitExpr VIE(AllocType);
  if (!EvaluateInPlace(*Val, Info, Result, &VIE))
    return false;
} else if (ResizedArrayILE) {
  if (!EvaluateArrayNewInitList(Info, Result, *Val, ResizedArrayILE,
                                AllocType))
    return false;
} else if (ResizedArrayCCE) {
  if (!EvaluateArrayNewConstructExpr(Info, Result, *Val, ResizedArrayCCE,
                                     AllocType))
    return false;
} else if (Init) {
  if (!EvaluateInPlace(*Val, Info, Result, Init))
    return false;
} else if (!getDefaultInitValue(AllocType, *Val)) {
  return false;
}

// Array new returns a pointer to the first element, not a pointer to the
// array.
if (auto *AT = AllocType->getAsArrayTypeUnsafe())
  Result.addArray(Info, E, cast<ConstantArrayType>(AT));

return true;
9552}
9553//===----------------------------------------------------------------------===//
9554// Member Pointer Evaluation
9555//===----------------------------------------------------------------------===//

9557namespace {
9558class MemberPointerExprEvaluator
: public ExprEvaluatorBase<MemberPointerExprEvaluator> {
MemberPtr &Result;

bool Success(const ValueDecl *D) {
  Result = MemberPtr(D);
  return true;
}
9566public:

MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
  : ExprEvaluatorBaseTy(Info), Result(Result) {}

bool Success(const APValue &V, const Expr *E) {
  Result.setFrom(V);
  return true;
}
bool ZeroInitialization(const Expr *E) {
  return Success((const ValueDecl*)nullptr);
}

bool VisitCastExpr(const CastExpr *E);
bool VisitUnaryAddrOf(const UnaryOperator *E);
9581};
9582} // end anonymous namespace

9584static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
                                EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isMemberPointerType())((void)0);
return MemberPointerExprEvaluator(Info, Result).Visit(E);
9589}

9591bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
switch (E->getCastKind()) {
default:
  return ExprEvaluatorBaseTy::VisitCastExpr(E);

case CK_NullToMemberPointer:
  VisitIgnoredValue(E->getSubExpr());
  return ZeroInitialization(E);

case CK_BaseToDerivedMemberPointer: {
  if (!Visit(E->getSubExpr()))
    return false;
  if (E->path_empty())
    return true;
  // Base-to-derived member pointer casts store the path in derived-to-base
  // order, so iterate backwards. The CXXBaseSpecifier also provides us with
  // the wrong end of the derived->base arc, so stagger the path by one class.
  typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
  for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
       PathI != PathE; ++PathI) {
    assert(!(*PathI)->isVirtual() && "memptr cast through vbase")((void)0);
    const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
    if (!Result.castToDerived(Derived))
      return Error(E);
  }
  const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
  if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
    return Error(E);
  return true;
}

case CK_DerivedToBaseMemberPointer:
  if (!Visit(E->getSubExpr()))
    return false;
  for (CastExpr::path_const_iterator PathI = E->path_begin(),
       PathE = E->path_end(); PathI != PathE; ++PathI) {
    assert(!(*PathI)->isVirtual() && "memptr cast through vbase")((void)0);
    const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
    if (!Result.castToBase(Base))
      return Error(E);
  }
  return true;
}
9634}

9636bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
// C++11 [expr.unary.op]p3 has very strict rules on how the address of a
// member can be formed.
return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
9640}

9642//===----------------------------------------------------------------------===//
9643// Record Evaluation
9644//===----------------------------------------------------------------------===//

9646namespace {
class RecordExprEvaluator
: public ExprEvaluatorBase<RecordExprEvaluator> {
  const LValue &This;
  APValue &Result;
public:

  RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
    : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}

  bool Success(const APValue &V, const Expr *E) {
    Result = V;
    return true;
  }
  bool ZeroInitialization(const Expr *E) {
    return ZeroInitialization(E, E->getType());
  }
  bool ZeroInitialization(const Expr *E, QualType T);

  bool VisitCallExpr(const CallExpr *E) {
    return handleCallExpr(E, Result, &This);
  }
  bool VisitCastExpr(const CastExpr *E);
  bool VisitInitListExpr(const InitListExpr *E);
  bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
    return VisitCXXConstructExpr(E, E->getType());
  }
  bool VisitLambdaExpr(const LambdaExpr *E);
  bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
  bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
  bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
  bool VisitBinCmp(const BinaryOperator *E);
};
9679}

9681/// Perform zero-initialization on an object of non-union class type.
9682/// C++11 [dcl.init]p5:
9683///  To zero-initialize an object or reference of type T means:
9684///    [...]
9685///    -- if T is a (possibly cv-qualified) non-union class type,
9686///       each non-static data member and each base-class subobject is
9687///       zero-initialized
9688static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
                                        const RecordDecl *RD,
                                        const LValue &This, APValue &Result) {
assert(!RD->isUnion() && "Expected non-union class type")((void)0);
const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
                 std::distance(RD->field_begin(), RD->field_end()));

if (RD->isInvalidDecl()) return false;
const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);

if (CD) {
  unsigned Index = 0;
  for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
         End = CD->bases_end(); I != End; ++I, ++Index) {
    const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
    LValue Subobject = This;
    if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
      return false;
    if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
                                       Result.getStructBase(Index)))
      return false;
  }
}

for (const auto *I : RD->fields()) {
  // -- if T is a reference type, no initialization is performed.
  if (I->isUnnamedBitfield() || I->getType()->isReferenceType())
    continue;

  LValue Subobject = This;
  if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
    return false;

  ImplicitValueInitExpr VIE(I->getType());
  if (!EvaluateInPlace(
        Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
    return false;
}

return true;
9729}

9731bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
if (RD->isInvalidDecl()) return false;
if (RD->isUnion()) {
  // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
  // object's first non-static named data member is zero-initialized
  RecordDecl::field_iterator I = RD->field_begin();
  while (I != RD->field_end() && (*I)->isUnnamedBitfield())
    ++I;
  if (I == RD->field_end()) {
    Result = APValue((const FieldDecl*)nullptr);
    return true;
  }

  LValue Subobject = This;
  if (!HandleLValueMember(Info, E, Subobject, *I))
    return false;
  Result = APValue(*I);
  ImplicitValueInitExpr VIE(I->getType());
  return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
}

if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
  Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
  return false;
}

return HandleClassZeroInitialization(Info, E, RD, This, Result);
9759}

9761bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
switch (E->getCastKind()) {
default:
  return ExprEvaluatorBaseTy::VisitCastExpr(E);

case CK_ConstructorConversion:
  return Visit(E->getSubExpr());

case CK_DerivedToBase:
case CK_UncheckedDerivedToBase: {
  APValue DerivedObject;
  if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
    return false;
  if (!DerivedObject.isStruct())
    return Error(E->getSubExpr());

  // Derived-to-base rvalue conversion: just slice off the derived part.
  APValue *Value = &DerivedObject;
  const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
  for (CastExpr::path_const_iterator PathI = E->path_begin(),
       PathE = E->path_end(); PathI != PathE; ++PathI) {
    assert(!(*PathI)->isVirtual() && "record rvalue with virtual base")((void)0);
    const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
    Value = &Value->getStructBase(getBaseIndex(RD, Base));
    RD = Base;
  }
  Result = *Value;
  return true;
}
}
9791}

9793bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
if (E->isTransparent())
  return Visit(E->getInit(0));

const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
if (RD->isInvalidDecl()) return false;
const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);

EvalInfo::EvaluatingConstructorRAII EvalObj(
    Info,
    ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
    CXXRD && CXXRD->getNumBases());

if (RD->isUnion()) {
  const FieldDecl *Field = E->getInitializedFieldInUnion();
  Result = APValue(Field);
  if (!Field)
    return true;

  // If the initializer list for a union does not contain any elements, the
  // first element of the union is value-initialized.
  // FIXME: The element should be initialized from an initializer list.
  //        Is this difference ever observable for initializer lists which
  //        we don't build?
  ImplicitValueInitExpr VIE(Field->getType());
  const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;

  LValue Subobject = This;
  if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
    return false;

  // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
  ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
                                isa<CXXDefaultInitExpr>(InitExpr));

  if (EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr)) {
    if (Field->isBitField())
      return truncateBitfieldValue(Info, InitExpr, Result.getUnionValue(),
                                   Field);
    return true;
  }

  return false;
}

if (!Result.hasValue())
  Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
                   std::distance(RD->field_begin(), RD->field_end()));
unsigned ElementNo = 0;
bool Success = true;

// Initialize base classes.
if (CXXRD && CXXRD->getNumBases()) {
  for (const auto &Base : CXXRD->bases()) {
    assert(ElementNo < E->getNumInits() && "missing init for base class")((void)0);
    const Expr *Init = E->getInit(ElementNo);

    LValue Subobject = This;
    if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
      return false;

    APValue &FieldVal = Result.getStructBase(ElementNo);
    if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
      if (!Info.noteFailure())
        return false;
      Success = false;
    }
    ++ElementNo;
  }

  EvalObj.finishedConstructingBases();
}

// Initialize members.
for (const auto *Field : RD->fields()) {
  // Anonymous bit-fields are not considered members of the class for
  // purposes of aggregate initialization.
  if (Field->isUnnamedBitfield())
    continue;

  LValue Subobject = This;

  bool HaveInit = ElementNo < E->getNumInits();

  // FIXME: Diagnostics here should point to the end of the initializer
  // list, not the start.
  if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
                          Subobject, Field, &Layout))
    return false;

  // Perform an implicit value-initialization for members beyond the end of
  // the initializer list.
  ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
  const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;

  // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
  ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
                                isa<CXXDefaultInitExpr>(Init));

  APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
  if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
      (Field->isBitField() && !truncateBitfieldValue(Info, Init,
                                                     FieldVal, Field))) {
    if (!Info.noteFailure())
      return false;
    Success = false;
  }
}

EvalObj.finishedConstructingFields();

return Success;
9906}

9908bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
                                              QualType T) {
// Note that E's type is not necessarily the type of our class here; we might
// be initializing an array element instead.
const CXXConstructorDecl *FD = E->getConstructor();
if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;

bool ZeroInit = E->requiresZeroInitialization();
if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
  // If we've already performed zero-initialization, we're already done.
  if (Result.hasValue())
    return true;

  if (ZeroInit)
    return ZeroInitialization(E, T);

  return getDefaultInitValue(T, Result);
}

const FunctionDecl *Definition = nullptr;
auto Body = FD->getBody(Definition);

if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
  return false;

// Avoid materializing a temporary for an elidable copy/move constructor.
if (E->isElidable() && !ZeroInit) {
  // FIXME: This only handles the simplest case, where the source object
  //        is passed directly as the first argument to the constructor.
  //        This should also handle stepping though implicit casts and
  //        and conversion sequences which involve two steps, with a
  //        conversion operator followed by a converting constructor.
  const Expr *SrcObj = E->getArg(0);
  assert(SrcObj->isTemporaryObject(Info.Ctx, FD->getParent()))((void)0);
  assert(Info.Ctx.hasSameUnqualifiedType(E->getType(), SrcObj->getType()))((void)0);
  if (const MaterializeTemporaryExpr *ME =
          dyn_cast<MaterializeTemporaryExpr>(SrcObj))
    return Visit(ME->getSubExpr());
}

if (ZeroInit && !ZeroInitialization(E, T))
  return false;

auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
return HandleConstructorCall(E, This, Args,
                             cast<CXXConstructorDecl>(Definition), Info,
                             Result);
9955}

9957bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
  const CXXInheritedCtorInitExpr *E) {
if (!Info.CurrentCall) {
  assert(Info.checkingPotentialConstantExpression())((void)0);
  return false;
}

const CXXConstructorDecl *FD = E->getConstructor();
if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
  return false;

const FunctionDecl *Definition = nullptr;
auto Body = FD->getBody(Definition);

if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
  return false;

return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
                             cast<CXXConstructorDecl>(Definition), Info,
                             Result);
9977}

9979bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
  const CXXStdInitializerListExpr *E) {
const ConstantArrayType *ArrayType =
    Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());

LValue Array;
if (!EvaluateLValue(E->getSubExpr(), Array, Info))
  return false;

// Get a pointer to the first element of the array.
Array.addArray(Info, E, ArrayType);

auto InvalidType = [&] {
  Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
    << E->getType();
  return false;
};

// FIXME: Perform the checks on the field types in SemaInit.
RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
RecordDecl::field_iterator Field = Record->field_begin();
if (Field == Record->field_end())
  return InvalidType();

// Start pointer.
if (!Field->getType()->isPointerType() ||
    !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
                          ArrayType->getElementType()))
  return InvalidType();

// FIXME: What if the initializer_list type has base classes, etc?
Result = APValue(APValue::UninitStruct(), 0, 2);
Array.moveInto(Result.getStructField(0));

if (++Field == Record->field_end())
  return InvalidType();

if (Field->getType()->isPointerType() &&
    Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
                         ArrayType->getElementType())) {
  // End pointer.
  if (!HandleLValueArrayAdjustment(Info, E, Array,
                                   ArrayType->getElementType(),
                                   ArrayType->getSize().getZExtValue()))
    return false;
  Array.moveInto(Result.getStructField(1));
} else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
  // Length.
  Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
else
  return InvalidType();

if (++Field != Record->field_end())
  return InvalidType();

return true;
10035}

10037bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
const CXXRecordDecl *ClosureClass = E->getLambdaClass();
if (ClosureClass->isInvalidDecl())
  return false;

const size_t NumFields =
    std::distance(ClosureClass->field_begin(), ClosureClass->field_end());

assert(NumFields == (size_t)std::distance(E->capture_init_begin(),((void)0)
                                          E->capture_init_end()) &&((void)0)
       "The number of lambda capture initializers should equal the number of "((void)0)
       "fields within the closure type")((void)0);

Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
// Iterate through all the lambda's closure object's fields and initialize
// them.
auto *CaptureInitIt = E->capture_init_begin();
const LambdaCapture *CaptureIt = ClosureClass->captures_begin();
bool Success = true;
const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(ClosureClass);
for (const auto *Field : ClosureClass->fields()) {
  assert(CaptureInitIt != E->capture_init_end())((void)0);
  // Get the initializer for this field
  Expr *const CurFieldInit = *CaptureInitIt++;

  // If there is no initializer, either this is a VLA or an error has
  // occurred.
  if (!CurFieldInit)
    return Error(E);

  LValue Subobject = This;

  if (!HandleLValueMember(Info, E, Subobject, Field, &Layout))
    return false;

  APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
  if (!EvaluateInPlace(FieldVal, Info, Subobject, CurFieldInit)) {
    if (!Info.keepEvaluatingAfterFailure())
      return false;
    Success = false;
  }
  ++CaptureIt;
}
return Success;
10081}

10083static bool EvaluateRecord(const Expr *E, const LValue &This,
                         APValue &Result, EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isRecordType() &&((void)0)
       "can't evaluate expression as a record rvalue")((void)0);
return RecordExprEvaluator(Info, This, Result).Visit(E);
10089}

10091//===----------------------------------------------------------------------===//
10092// Temporary Evaluation
10093//
10094// Temporaries are represented in the AST as rvalues, but generally behave like
10095// lvalues. The full-object of which the temporary is a subobject is implicitly
10096// materialized so that a reference can bind to it.
10097//===----------------------------------------------------------------------===//
10098namespace {
10099class TemporaryExprEvaluator
: public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
10101public:
TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
  LValueExprEvaluatorBaseTy(Info, Result, false) {}

/// Visit an expression which constructs the value of this temporary.
bool VisitConstructExpr(const Expr *E) {
  APValue &Value = Info.CurrentCall->createTemporary(
      E, E->getType(), ScopeKind::FullExpression, Result);
  return EvaluateInPlace(Value, Info, Result, E);
}

bool VisitCastExpr(const CastExpr *E) {
  switch (E->getCastKind()) {
  default:
    return LValueExprEvaluatorBaseTy::VisitCastExpr(E);

  case CK_ConstructorConversion:
    return VisitConstructExpr(E->getSubExpr());
  }
}
bool VisitInitListExpr(const InitListExpr *E) {
  return VisitConstructExpr(E);
}
bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
  return VisitConstructExpr(E);
}
bool VisitCallExpr(const CallExpr *E) {
  return VisitConstructExpr(E);
}
bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
  return VisitConstructExpr(E);
}
bool VisitLambdaExpr(const LambdaExpr *E) {
  return VisitConstructExpr(E);
}
10136};
10137} // end anonymous namespace

10139/// Evaluate an expression of record type as a temporary.
10140static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isRecordType())((void)0);
return TemporaryExprEvaluator(Info, Result).Visit(E);
10144}

10146//===----------------------------------------------------------------------===//
10147// Vector Evaluation
10148//===----------------------------------------------------------------------===//

10150namespace {
class VectorExprEvaluator
: public ExprEvaluatorBase<VectorExprEvaluator> {
  APValue &Result;
public:

  VectorExprEvaluator(EvalInfo &info, APValue &Result)
    : ExprEvaluatorBaseTy(info), Result(Result) {}

  bool Success(ArrayRef<APValue> V, const Expr *E) {
    assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements())((void)0);
    // FIXME: remove this APValue copy.
    Result = APValue(V.data(), V.size());
    return true;
  }
  bool Success(const APValue &V, const Expr *E) {
    assert(V.isVector())((void)0);
    Result = V;
    return true;
  }
  bool ZeroInitialization(const Expr *E);

  bool VisitUnaryReal(const UnaryOperator *E)
    { return Visit(E->getSubExpr()); }
  bool VisitCastExpr(const CastExpr* E);
  bool VisitInitListExpr(const InitListExpr *E);
  bool VisitUnaryImag(const UnaryOperator *E);
  bool VisitBinaryOperator(const BinaryOperator *E);
  // FIXME: Missing: unary -, unary ~, conditional operator (for GNU
  //                 conditional select), shufflevector, ExtVectorElementExpr
};
10181} // end anonymous namespace

10183static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
assert(E->isPRValue() && E->getType()->isVectorType() &&((void)0)
       "not a vector prvalue")((void)0);
return VectorExprEvaluator(Info, Result).Visit(E);
10187}

10189bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
const VectorType *VTy = E->getType()->castAs<VectorType>();
unsigned NElts = VTy->getNumElements();

const Expr *SE = E->getSubExpr();
QualType SETy = SE->getType();

switch (E->getCastKind()) {
case CK_VectorSplat: {
  APValue Val = APValue();
  if (SETy->isIntegerType()) {
    APSInt IntResult;
    if (!EvaluateInteger(SE, IntResult, Info))
      return false;
    Val = APValue(std::move(IntResult));
  } else if (SETy->isRealFloatingType()) {
    APFloat FloatResult(0.0);
    if (!EvaluateFloat(SE, FloatResult, Info))
      return false;
    Val = APValue(std::move(FloatResult));
  } else {
    return Error(E);
  }

  // Splat and create vector APValue.
  SmallVector<APValue, 4> Elts(NElts, Val);
  return Success(Elts, E);
}
case CK_BitCast: {
  // Evaluate the operand into an APInt we can extract from.
  llvm::APInt SValInt;
  if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
    return false;
  // Extract the elements
  QualType EltTy = VTy->getElementType();
  unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
  bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
  SmallVector<APValue, 4> Elts;
  if (EltTy->isRealFloatingType()) {
    const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
    unsigned FloatEltSize = EltSize;
    if (&Sem == &APFloat::x87DoubleExtended())
      FloatEltSize = 80;
    for (unsigned i = 0; i < NElts; i++) {
      llvm::APInt Elt;
      if (BigEndian)
        Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
      else
        Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
      Elts.push_back(APValue(APFloat(Sem, Elt)));
    }
  } else if (EltTy->isIntegerType()) {
    for (unsigned i = 0; i < NElts; i++) {
      llvm::APInt Elt;
      if (BigEndian)
        Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
      else
        Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
      Elts.push_back(APValue(APSInt(Elt, !EltTy->isSignedIntegerType())));
    }
  } else {
    return Error(E);
  }
  return Success(Elts, E);
}
default:
  return ExprEvaluatorBaseTy::VisitCastExpr(E);
}
10257}

10259bool
10260VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
const VectorType *VT = E->getType()->castAs<VectorType>();
unsigned NumInits = E->getNumInits();
unsigned NumElements = VT->getNumElements();

QualType EltTy = VT->getElementType();
SmallVector<APValue, 4> Elements;

// The number of initializers can be less than the number of
// vector elements. For OpenCL, this can be due to nested vector
// initialization. For GCC compatibility, missing trailing elements
// should be initialized with zeroes.
unsigned CountInits = 0, CountElts = 0;
while (CountElts < NumElements) {
  // Handle nested vector initialization.
  if (CountInits < NumInits
      && E->getInit(CountInits)->getType()->isVectorType()) {
    APValue v;
    if (!EvaluateVector(E->getInit(CountInits), v, Info))
      return Error(E);
    unsigned vlen = v.getVectorLength();
    for (unsigned j = 0; j < vlen; j++)
      Elements.push_back(v.getVectorElt(j));
    CountElts += vlen;
  } else if (EltTy->isIntegerType()) {
    llvm::APSInt sInt(32);
    if (CountInits < NumInits) {
      if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
        return false;
    } else // trailing integer zero.
      sInt = Info.Ctx.MakeIntValue(0, EltTy);
    Elements.push_back(APValue(sInt));
    CountElts++;
  } else {
    llvm::APFloat f(0.0);
    if (CountInits < NumInits) {
      if (!EvaluateFloat(E->getInit(CountInits), f, Info))
        return false;
    } else // trailing float zero.
      f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
    Elements.push_back(APValue(f));
    CountElts++;
  }
  CountInits++;
}
return Success(Elements, E);
10306}

10308bool
10309VectorExprEvaluator::ZeroInitialization(const Expr *E) {
const auto *VT = E->getType()->castAs<VectorType>();
QualType EltTy = VT->getElementType();
APValue ZeroElement;
if (EltTy->isIntegerType())
  ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
else
  ZeroElement =
      APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));

SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
return Success(Elements, E);
10321}

10323bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
VisitIgnoredValue(E->getSubExpr());
return ZeroInitialization(E);
10326}

10328bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
BinaryOperatorKind Op = E->getOpcode();
assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp &&((void)0)
       "Operation not supported on vector types")((void)0);

if (Op == BO_Comma)
  return ExprEvaluatorBaseTy::VisitBinaryOperator(E);

Expr *LHS = E->getLHS();
Expr *RHS = E->getRHS();

assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() &&((void)0)
       "Must both be vector types")((void)0);
// Checking JUST the types are the same would be fine, except shifts don't
// need to have their types be the same (since you always shift by an int).
assert(LHS->getType()->castAs<VectorType>()->getNumElements() ==((void)0)
           E->getType()->castAs<VectorType>()->getNumElements() &&((void)0)
       RHS->getType()->castAs<VectorType>()->getNumElements() ==((void)0)
           E->getType()->castAs<VectorType>()->getNumElements() &&((void)0)
       "All operands must be the same size.")((void)0);

APValue LHSValue;
APValue RHSValue;
bool LHSOK = Evaluate(LHSValue, Info, LHS);
if (!LHSOK && !Info.noteFailure())
  return false;
if (!Evaluate(RHSValue, Info, RHS) || !LHSOK)
  return false;

if (!handleVectorVectorBinOp(Info, E, Op, LHSValue, RHSValue))
  return false;

return Success(LHSValue, E);
10361}

10363//===----------------------------------------------------------------------===//
10364// Array Evaluation
10365//===----------------------------------------------------------------------===//

10367namespace {
class ArrayExprEvaluator
: public ExprEvaluatorBase<ArrayExprEvaluator> {
  const LValue &This;
  APValue &Result;
public:

  ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
    : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}

  bool Success(const APValue &V, const Expr *E) {
    assert(V.isArray() && "expected array")((void)0);
    Result = V;
    return true;
  }

  bool ZeroInitialization(const Expr *E) {
    const ConstantArrayType *CAT =
        Info.Ctx.getAsConstantArrayType(E->getType());
    if (!CAT) {
      if (E->getType()->isIncompleteArrayType()) {
        // We can be asked to zero-initialize a flexible array member; this
        // is represented as an ImplicitValueInitExpr of incomplete array
        // type. In this case, the array has zero elements.
        Result = APValue(APValue::UninitArray(), 0, 0);
        return true;
      }
      // FIXME: We could handle VLAs here.
      return Error(E);
    }

    Result = APValue(APValue::UninitArray(), 0,
                     CAT->getSize().getZExtValue());
    if (!Result.hasArrayFiller())
      return true;

    // Zero-initialize all elements.
    LValue Subobject = This;
    Subobject.addArray(Info, E, CAT);
    ImplicitValueInitExpr VIE(CAT->getElementType());
    return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
  }

  bool VisitCallExpr(const CallExpr *E) {
    return handleCallExpr(E, Result, &This);
  }
  bool VisitInitListExpr(const InitListExpr *E,
                         QualType AllocType = QualType());
  bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
  bool VisitCXXConstructExpr(const CXXConstructExpr *E);
  bool VisitCXXConstructExpr(const CXXConstructExpr *E,
                             const LValue &Subobject,
                             APValue *Value, QualType Type);
  bool VisitStringLiteral(const StringLiteral *E,
                          QualType AllocType = QualType()) {
    expandStringLiteral(Info, E, Result, AllocType);
    return true;
  }
};
10426} // end anonymous namespace

10428static bool EvaluateArray(const Expr *E, const LValue &This,
                        APValue &Result, EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isArrayType() &&((void)0)
       "not an array prvalue")((void)0);
return ArrayExprEvaluator(Info, This, Result).Visit(E);
10434}

10436static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
                                   APValue &Result, const InitListExpr *ILE,
                                   QualType AllocType) {
assert(!ILE->isValueDependent())((void)0);
assert(ILE->isPRValue() && ILE->getType()->isArrayType() &&((void)0)
       "not an array prvalue")((void)0);
return ArrayExprEvaluator(Info, This, Result)
    .VisitInitListExpr(ILE, AllocType);
10444}

10446static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
                                        APValue &Result,
                                        const CXXConstructExpr *CCE,
                                        QualType AllocType) {
assert(!CCE->isValueDependent())((void)0);
assert(CCE->isPRValue() && CCE->getType()->isArrayType() &&((void)0)
       "not an array prvalue")((void)0);
return ArrayExprEvaluator(Info, This, Result)
    .VisitCXXConstructExpr(CCE, This, &Result, AllocType);
10455}

10457// Return true iff the given array filler may depend on the element index.
10458static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) {
// For now, just allow non-class value-initialization and initialization
// lists comprised of them.
if (isa<ImplicitValueInitExpr>(FillerExpr))
  return false;
if (const InitListExpr *ILE = dyn_cast<InitListExpr>(FillerExpr)) {
  for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) {
    if (MaybeElementDependentArrayFiller(ILE->getInit(I)))
      return true;
  }
  return false;
}
return true;
10471}

10473bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E,
                                         QualType AllocType) {
const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
    AllocType.isNull() ? E->getType() : AllocType);
if (!CAT)
  return Error(E);

// C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
// an appropriately-typed string literal enclosed in braces.
if (E->isStringLiteralInit()) {
  auto *SL = dyn_cast<StringLiteral>(E->getInit(0)->IgnoreParens());
  // FIXME: Support ObjCEncodeExpr here once we support it in
  // ArrayExprEvaluator generally.
  if (!SL)
    return Error(E);
  return VisitStringLiteral(SL, AllocType);
}

bool Success = true;

assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&((void)0)
       "zero-initialized array shouldn't have any initialized elts")((void)0);
APValue Filler;
if (Result.isArray() && Result.hasArrayFiller())
  Filler = Result.getArrayFiller();

unsigned NumEltsToInit = E->getNumInits();
unsigned NumElts = CAT->getSize().getZExtValue();
const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;

// If the initializer might depend on the array index, run it for each
// array element.
if (NumEltsToInit != NumElts && MaybeElementDependentArrayFiller(FillerExpr))
  NumEltsToInit = NumElts;

LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: "do { } while (false)
                        << NumEltsToInit << ".\n")do { } while (false);

Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);

// If the array was previously zero-initialized, preserve the
// zero-initialized values.
if (Filler.hasValue()) {
  for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
    Result.getArrayInitializedElt(I) = Filler;
  if (Result.hasArrayFiller())
    Result.getArrayFiller() = Filler;
}

LValue Subobject = This;
Subobject.addArray(Info, E, CAT);
for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
  const Expr *Init =
      Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
  if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
                       Info, Subobject, Init) ||
      !HandleLValueArrayAdjustment(Info, Init, Subobject,
                                   CAT->getElementType(), 1)) {
    if (!Info.noteFailure())
      return false;
    Success = false;
  }
}

if (!Result.hasArrayFiller())
  return Success;

// If we get here, we have a trivial filler, which we can just evaluate
// once and splat over the rest of the array elements.
assert(FillerExpr && "no array filler for incomplete init list")((void)0);
return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
                       FillerExpr) && Success;
10545}

10547bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
LValue CommonLV;
if (E->getCommonExpr() &&
    !Evaluate(Info.CurrentCall->createTemporary(
                  E->getCommonExpr(),
                  getStorageType(Info.Ctx, E->getCommonExpr()),
                  ScopeKind::FullExpression, CommonLV),
              Info, E->getCommonExpr()->getSourceExpr()))
  return false;

auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());

uint64_t Elements = CAT->getSize().getZExtValue();
Result = APValue(APValue::UninitArray(), Elements, Elements);

LValue Subobject = This;
Subobject.addArray(Info, E, CAT);

bool Success = true;
for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
  if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
                       Info, Subobject, E->getSubExpr()) ||
      !HandleLValueArrayAdjustment(Info, E, Subobject,
                                   CAT->getElementType(), 1)) {
    if (!Info.noteFailure())
      return false;
    Success = false;
  }
}

return Success;
10578}

10580bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
return VisitCXXConstructExpr(E, This, &Result, E->getType());
10582}

10584bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
                                             const LValue &Subobject,
                                             APValue *Value,
                                             QualType Type) {
bool HadZeroInit = Value->hasValue();

if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
  unsigned N = CAT->getSize().getZExtValue();

  // Preserve the array filler if we had prior zero-initialization.
  APValue Filler =
    HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
                                           : APValue();

  *Value = APValue(APValue::UninitArray(), N, N);

  if (HadZeroInit)
    for (unsigned I = 0; I != N; ++I)
      Value->getArrayInitializedElt(I) = Filler;

  // Initialize the elements.
  LValue ArrayElt = Subobject;
  ArrayElt.addArray(Info, E, CAT);
  for (unsigned I = 0; I != N; ++I)
    if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
                               CAT->getElementType()) ||
        !HandleLValueArrayAdjustment(Info, E, ArrayElt,
                                     CAT->getElementType(), 1))
      return false;

  return true;
}

if (!Type->isRecordType())
  return Error(E);

return RecordExprEvaluator(Info, Subobject, *Value)
           .VisitCXXConstructExpr(E, Type);
10622}

10624//===----------------------------------------------------------------------===//
10625// Integer Evaluation
10626//
10627// As a GNU extension, we support casting pointers to sufficiently-wide integer
10628// types and back in constant folding. Integer values are thus represented
10629// either as an integer-valued APValue, or as an lvalue-valued APValue.
10630//===----------------------------------------------------------------------===//

10632namespace {
10633class IntExprEvaluator
      : public ExprEvaluatorBase<IntExprEvaluator> {
APValue &Result;
10636public:
IntExprEvaluator(EvalInfo &info, APValue &result)
    : ExprEvaluatorBaseTy(info), Result(result) {}

bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
  assert(E->getType()->isIntegralOrEnumerationType() &&((void)0)
         "Invalid evaluation result.")((void)0);
  assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&((void)0)
         "Invalid evaluation result.")((void)0);
  assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&((void)0)
         "Invalid evaluation result.")((void)0);
  Result = APValue(SI);
  return true;
}
bool Success(const llvm::APSInt &SI, const Expr *E) {
  return Success(SI, E, Result);
}

bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
  assert(E->getType()->isIntegralOrEnumerationType() &&((void)0)
         "Invalid evaluation result.")((void)0);
  assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&((void)0)
         "Invalid evaluation result.")((void)0);
  Result = APValue(APSInt(I));
  Result.getInt().setIsUnsigned(
                          E->getType()->isUnsignedIntegerOrEnumerationType());
  return true;
}
bool Success(const llvm::APInt &I, const Expr *E) {
  return Success(I, E, Result);
}

bool Success(uint64_t Value, const Expr *E, APValue &Result) {
  assert(E->getType()->isIntegralOrEnumerationType() &&((void)0)
         "Invalid evaluation result.")((void)0);
  Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
  return true;
}
bool Success(uint64_t Value, const Expr *E) {
  return Success(Value, E, Result);
}

bool Success(CharUnits Size, const Expr *E) {
  return Success(Size.getQuantity(), E);
}

bool Success(const APValue &V, const Expr *E) {
  if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate()) {
    Result = V;
    return true;
  }
  return Success(V.getInt(), E);
}

bool ZeroInitialization(const Expr *E) { return Success(0, E); }

//===--------------------------------------------------------------------===//
//                            Visitor Methods
//===--------------------------------------------------------------------===//

bool VisitIntegerLiteral(const IntegerLiteral *E) {
  return Success(E->getValue(), E);
}
bool VisitCharacterLiteral(const CharacterLiteral *E) {
  return Success(E->getValue(), E);
}

bool CheckReferencedDecl(const Expr *E, const Decl *D);
bool VisitDeclRefExpr(const DeclRefExpr *E) {
  if (CheckReferencedDecl(E, E->getDecl()))
    return true;

  return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
}
bool VisitMemberExpr(const MemberExpr *E) {
  if (CheckReferencedDecl(E, E->getMemberDecl())) {
    VisitIgnoredBaseExpression(E->getBase());
    return true;
  }

  return ExprEvaluatorBaseTy::VisitMemberExpr(E);
}

bool VisitCallExpr(const CallExpr *E);
bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitOffsetOfExpr(const OffsetOfExpr *E);
bool VisitUnaryOperator(const UnaryOperator *E);

bool VisitCastExpr(const CastExpr* E);
bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);

bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
  return Success(E->getValue(), E);
}

bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
  return Success(E->getValue(), E);
}

bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
  if (Info.ArrayInitIndex == uint64_t(-1)) {
    // We were asked to evaluate this subexpression independent of the
    // enclosing ArrayInitLoopExpr. We can't do that.
    Info.FFDiag(E);
    return false;
  }
  return Success(Info.ArrayInitIndex, E);
}

// Note, GNU defines __null as an integer, not a pointer.
bool VisitGNUNullExpr(const GNUNullExpr *E) {
  return ZeroInitialization(E);
}

bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
  return Success(E->getValue(), E);
}

bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
  return Success(E->getValue(), E);
}

bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
  return Success(E->getValue(), E);
}

bool VisitUnaryReal(const UnaryOperator *E);
bool VisitUnaryImag(const UnaryOperator *E);

bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
bool VisitSourceLocExpr(const SourceLocExpr *E);
bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E);
bool VisitRequiresExpr(const RequiresExpr *E);
// FIXME: Missing: array subscript of vector, member of vector
10772};

10774class FixedPointExprEvaluator
  : public ExprEvaluatorBase<FixedPointExprEvaluator> {
APValue &Result;

public:
FixedPointExprEvaluator(EvalInfo &info, APValue &result)
    : ExprEvaluatorBaseTy(info), Result(result) {}

bool Success(const llvm::APInt &I, const Expr *E) {
  return Success(
      APFixedPoint(I, Info.Ctx.getFixedPointSemantics(E->getType())), E);
}

bool Success(uint64_t Value, const Expr *E) {
  return Success(
      APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(E->getType())), E);
}

bool Success(const APValue &V, const Expr *E) {
  return Success(V.getFixedPoint(), E);
}

bool Success(const APFixedPoint &V, const Expr *E) {
  assert(E->getType()->isFixedPointType() && "Invalid evaluation result.")((void)0);
  assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) &&((void)0)
         "Invalid evaluation result.")((void)0);
  Result = APValue(V);
  return true;
}

//===--------------------------------------------------------------------===//
//                            Visitor Methods
//===--------------------------------------------------------------------===//

bool VisitFixedPointLiteral(const FixedPointLiteral *E) {
  return Success(E->getValue(), E);
}

bool VisitCastExpr(const CastExpr *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitBinaryOperator(const BinaryOperator *E);
10815};
10816} // end anonymous namespace

10818/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
10819/// produce either the integer value or a pointer.
10820///
10821/// GCC has a heinous extension which folds casts between pointer types and
10822/// pointer-sized integral types. We support this by allowing the evaluation of
10823/// an integer rvalue to produce a pointer (represented as an lvalue) instead.
10824/// Some simple arithmetic on such values is supported (they are treated much
10825/// like char*).
10826static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
                                  EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isIntegralOrEnumerationType())((void)0);
return IntExprEvaluator(Info, Result).Visit(E);
10831}

10833static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
APValue Val;
if (!EvaluateIntegerOrLValue(E, Val, Info))
  return false;
if (!Val.isInt()) {
  // FIXME: It would be better to produce the diagnostic for casting
  //        a pointer to an integer.
  Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
  return false;
}
Result = Val.getInt();
return true;
10846}

10848bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) {
APValue Evaluated = E->EvaluateInContext(
    Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
return Success(Evaluated, E);
10852}

10854static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
                             EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
if (E->getType()->isFixedPointType()) {
  APValue Val;
  if (!FixedPointExprEvaluator(Info, Val).Visit(E))
    return false;
  if (!Val.isFixedPoint())
    return false;

  Result = Val.getFixedPoint();
  return true;
}
return false;
10868}

10870static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
                                      EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
if (E->getType()->isIntegerType()) {
  auto FXSema = Info.Ctx.getFixedPointSemantics(E->getType());
  APSInt Val;
  if (!EvaluateInteger(E, Val, Info))
    return false;
  Result = APFixedPoint(Val, FXSema);
  return true;
} else if (E->getType()->isFixedPointType()) {
  return EvaluateFixedPoint(E, Result, Info);
}
return false;
10884}

10886/// Check whether the given declaration can be directly converted to an integral
10887/// rvalue. If not, no diagnostic is produced; there are other things we can
10888/// try.
10889bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
// Enums are integer constant exprs.
if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
  // Check for signedness/width mismatches between E type and ECD value.
  bool SameSign = (ECD->getInitVal().isSigned()
                   == E->getType()->isSignedIntegerOrEnumerationType());
  bool SameWidth = (ECD->getInitVal().getBitWidth()
                    == Info.Ctx.getIntWidth(E->getType()));
  if (SameSign && SameWidth)
    return Success(ECD->getInitVal(), E);
  else {
    // Get rid of mismatch (otherwise Success assertions will fail)
    // by computing a new value matching the type of E.
    llvm::APSInt Val = ECD->getInitVal();
    if (!SameSign)
      Val.setIsSigned(!ECD->getInitVal().isSigned());
    if (!SameWidth)
      Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
    return Success(Val, E);
  }
}
return false;
10911}

10913/// Values returned by __builtin_classify_type, chosen to match the values
10914/// produced by GCC's builtin.
10915enum class GCCTypeClass {
None = -1,
Void = 0,
Integer = 1,
// GCC reserves 2 for character types, but instead classifies them as
// integers.
Enum = 3,
Bool = 4,
Pointer = 5,
// GCC reserves 6 for references, but appears to never use it (because
// expressions never have reference type, presumably).
PointerToDataMember = 7,
RealFloat = 8,
Complex = 9,
// GCC reserves 10 for functions, but does not use it since GCC version 6 due
// to decay to pointer. (Prior to version 6 it was only used in C++ mode).
// GCC claims to reserve 11 for pointers to member functions, but *actually*
// uses 12 for that purpose, same as for a class or struct. Maybe it
// internally implements a pointer to member as a struct?  Who knows.
PointerToMemberFunction = 12, // Not a bug, see above.
ClassOrStruct = 12,
Union = 13,
// GCC reserves 14 for arrays, but does not use it since GCC version 6 due to
// decay to pointer. (Prior to version 6 it was only used in C++ mode).
// GCC reserves 15 for strings, but actually uses 5 (pointer) for string
// literals.
10941};

10943/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
10944/// as GCC.
10945static GCCTypeClass
10946EvaluateBuiltinClassifyType(QualType T, const LangOptions &LangOpts) {
assert(!T->isDependentType() && "unexpected dependent type")((void)0);

QualType CanTy = T.getCanonicalType();
const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);

switch (CanTy->getTypeClass()) {
10953#define TYPE(ID, BASE)
10954#define DEPENDENT_TYPE(ID, BASE) case Type::ID:
10955#define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
10956#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
10957#include "clang/AST/TypeNodes.inc"
case Type::Auto:
case Type::DeducedTemplateSpecialization:
    llvm_unreachable("unexpected non-canonical or dependent type")__builtin_unreachable();

case Type::Builtin:
  switch (BT->getKind()) {
10964#define BUILTIN_TYPE(ID, SINGLETON_ID)
10965#define SIGNED_TYPE(ID, SINGLETON_ID) \
  case BuiltinType::ID: return GCCTypeClass::Integer;
10967#define FLOATING_TYPE(ID, SINGLETON_ID) \
  case BuiltinType::ID: return GCCTypeClass::RealFloat;
10969#define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \
  case BuiltinType::ID: break;
10971#include "clang/AST/BuiltinTypes.def"
  case BuiltinType::Void:
    return GCCTypeClass::Void;

  case BuiltinType::Bool:
    return GCCTypeClass::Bool;

  case BuiltinType::Char_U:
  case BuiltinType::UChar:
  case BuiltinType::WChar_U:
  case BuiltinType::Char8:
  case BuiltinType::Char16:
  case BuiltinType::Char32:
  case BuiltinType::UShort:
  case BuiltinType::UInt:
  case BuiltinType::ULong:
  case BuiltinType::ULongLong:
  case BuiltinType::UInt128:
    return GCCTypeClass::Integer;

  case BuiltinType::UShortAccum:
  case BuiltinType::UAccum:
  case BuiltinType::ULongAccum:
  case BuiltinType::UShortFract:
  case BuiltinType::UFract:
  case BuiltinType::ULongFract:
  case BuiltinType::SatUShortAccum:
  case BuiltinType::SatUAccum:
  case BuiltinType::SatULongAccum:
  case BuiltinType::SatUShortFract:
  case BuiltinType::SatUFract:
  case BuiltinType::SatULongFract:
    return GCCTypeClass::None;

  case BuiltinType::NullPtr:

  case BuiltinType::ObjCId:
  case BuiltinType::ObjCClass:
  case BuiltinType::ObjCSel:
11010#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
  case BuiltinType::Id:
11012#include "clang/Basic/OpenCLImageTypes.def"
11013#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
  case BuiltinType::Id:
11015#include "clang/Basic/OpenCLExtensionTypes.def"
  case BuiltinType::OCLSampler:
  case BuiltinType::OCLEvent:
  case BuiltinType::OCLClkEvent:
  case BuiltinType::OCLQueue:
  case BuiltinType::OCLReserveID:
11021#define SVE_TYPE(Name, Id, SingletonId) \
  case BuiltinType::Id:
11023#include "clang/Basic/AArch64SVEACLETypes.def"
11024#define PPC_VECTOR_TYPE(Name, Id, Size) \
  case BuiltinType::Id:
11026#include "clang/Basic/PPCTypes.def"
11027#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
11028#include "clang/Basic/RISCVVTypes.def"
    return GCCTypeClass::None;

  case BuiltinType::Dependent:
    llvm_unreachable("unexpected dependent type")__builtin_unreachable();
  };
  llvm_unreachable("unexpected placeholder type")__builtin_unreachable();

case Type::Enum:
  return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer;

case Type::Pointer:
case Type::ConstantArray:
case Type::VariableArray:
case Type::IncompleteArray:
case Type::FunctionNoProto:
case Type::FunctionProto:
  return GCCTypeClass::Pointer;

case Type::MemberPointer:
  return CanTy->isMemberDataPointerType()
             ? GCCTypeClass::PointerToDataMember
             : GCCTypeClass::PointerToMemberFunction;

case Type::Complex:
  return GCCTypeClass::Complex;

case Type::Record:
  return CanTy->isUnionType() ? GCCTypeClass::Union
                              : GCCTypeClass::ClassOrStruct;

case Type::Atomic:
  // GCC classifies _Atomic T the same as T.
  return EvaluateBuiltinClassifyType(
      CanTy->castAs<AtomicType>()->getValueType(), LangOpts);

case Type::BlockPointer:
case Type::Vector:
case Type::ExtVector:
case Type::ConstantMatrix:
case Type::ObjCObject:
case Type::ObjCInterface:
case Type::ObjCObjectPointer:
case Type::Pipe:
case Type::ExtInt:
  // GCC classifies vectors as None. We follow its lead and classify all
  // other types that don't fit into the regular classification the same way.
  return GCCTypeClass::None;

case Type::LValueReference:
case Type::RValueReference:
  llvm_unreachable("invalid type for expression")__builtin_unreachable();
}

llvm_unreachable("unexpected type class")__builtin_unreachable();
11083}

11085/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
11086/// as GCC.
11087static GCCTypeClass
11088EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) {
// If no argument was supplied, default to None. This isn't
// ideal, however it is what gcc does.
if (E->getNumArgs() == 0)
  return GCCTypeClass::None;

// FIXME: Bizarrely, GCC treats a call with more than one argument as not
// being an ICE, but still folds it to a constant using the type of the first
// argument.
return EvaluateBuiltinClassifyType(E->getArg(0)->getType(), LangOpts);
11098}

11100/// EvaluateBuiltinConstantPForLValue - Determine the result of
11101/// __builtin_constant_p when applied to the given pointer.
11102///
11103/// A pointer is only "constant" if it is null (or a pointer cast to integer)
11104/// or it points to the first character of a string literal.
11105static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) {
APValue::LValueBase Base = LV.getLValueBase();
if (Base.isNull()) {
  // A null base is acceptable.
  return true;
} else if (const Expr *E = Base.dyn_cast<const Expr *>()) {
  if (!isa<StringLiteral>(E))
    return false;
  return LV.getLValueOffset().isZero();
} else if (Base.is<TypeInfoLValue>()) {
  // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to
  // evaluate to true.
  return true;
} else {
  // Any other base is not constant enough for GCC.
  return false;
}
11122}

11124/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
11125/// GCC as we can manage.
11126static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) {
// This evaluation is not permitted to have side-effects, so evaluate it in
// a speculative evaluation context.
SpeculativeEvaluationRAII SpeculativeEval(Info);

// Constant-folding is always enabled for the operand of __builtin_constant_p
// (even when the enclosing evaluation context otherwise requires a strict
// language-specific constant expression).
FoldConstant Fold(Info, true);

QualType ArgType = Arg->getType();

// __builtin_constant_p always has one operand. The rules which gcc follows
// are not precisely documented, but are as follows:
//
//  - If the operand is of integral, floating, complex or enumeration type,
//    and can be folded to a known value of that type, it returns 1.
//  - If the operand can be folded to a pointer to the first character
//    of a string literal (or such a pointer cast to an integral type)
//    or to a null pointer or an integer cast to a pointer, it returns 1.
//
// Otherwise, it returns 0.
//
// FIXME: GCC also intends to return 1 for literals of aggregate types, but
// its support for this did not work prior to GCC 9 and is not yet well
// understood.
if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() ||
    ArgType->isAnyComplexType() || ArgType->isPointerType() ||
    ArgType->isNullPtrType()) {
  APValue V;
  if (!::EvaluateAsRValue(Info, Arg, V) || Info.EvalStatus.HasSideEffects) {
    Fold.keepDiagnostics();
    return false;
  }

  // For a pointer (possibly cast to integer), there are special rules.
  if (V.getKind() == APValue::LValue)
    return EvaluateBuiltinConstantPForLValue(V);

  // Otherwise, any constant value is good enough.
  return V.hasValue();
}

// Anything else isn't considered to be sufficiently constant.
return false;
11171}

11173/// Retrieves the "underlying object type" of the given expression,
11174/// as used by __builtin_object_size.
11175static QualType getObjectType(APValue::LValueBase B) {
if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
  if (const VarDecl *VD = dyn_cast<VarDecl>(D))
    return VD->getType();
} else if (const Expr *E = B.dyn_cast<const Expr*>()) {
  if (isa<CompoundLiteralExpr>(E))
    return E->getType();
} else if (B.is<TypeInfoLValue>()) {
  return B.getTypeInfoType();
} else if (B.is<DynamicAllocLValue>()) {
  return B.getDynamicAllocType();
}

return QualType();
11189}

11191/// A more selective version of E->IgnoreParenCasts for
11192/// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
11193/// to change the type of E.
11194/// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
11195///
11196/// Always returns an RValue with a pointer representation.
11197static const Expr *ignorePointerCastsAndParens(const Expr *E) {
assert(E->isPRValue() && E->getType()->hasPointerRepresentation())((void)0);

auto *NoParens = E->IgnoreParens();
auto *Cast = dyn_cast<CastExpr>(NoParens);
if (Cast == nullptr)
  return NoParens;

// We only conservatively allow a few kinds of casts, because this code is
// inherently a simple solution that seeks to support the common case.
auto CastKind = Cast->getCastKind();
if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
    CastKind != CK_AddressSpaceConversion)
  return NoParens;

auto *SubExpr = Cast->getSubExpr();
if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isPRValue())
  return NoParens;
return ignorePointerCastsAndParens(SubExpr);
11216}

11218/// Checks to see if the given LValue's Designator is at the end of the LValue's
11219/// record layout. e.g.
11220///   struct { struct { int a, b; } fst, snd; } obj;
11221///   obj.fst   // no
11222///   obj.snd   // yes
11223///   obj.fst.a // no
11224///   obj.fst.b // no
11225///   obj.snd.a // no
11226///   obj.snd.b // yes
11227///
11228/// Please note: this function is specialized for how __builtin_object_size
11229/// views "objects".
11230///
11231/// If this encounters an invalid RecordDecl or otherwise cannot determine the
11232/// correct result, it will always return true.
11233static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
assert(!LVal.Designator.Invalid)((void)0);

auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
  const RecordDecl *Parent = FD->getParent();
  Invalid = Parent->isInvalidDecl();
  if (Invalid || Parent->isUnion())
    return true;
  const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
  return FD->getFieldIndex() + 1 == Layout.getFieldCount();
};

auto &Base = LVal.getLValueBase();
if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
  if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
    bool Invalid;
    if (!IsLastOrInvalidFieldDecl(FD, Invalid))
      return Invalid;
  } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
    for (auto *FD : IFD->chain()) {
      bool Invalid;
      if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
        return Invalid;
    }
  }
}

unsigned I = 0;
QualType BaseType = getType(Base);
if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
  // If we don't know the array bound, conservatively assume we're looking at
  // the final array element.
  ++I;
  if (BaseType->isIncompleteArrayType())
    BaseType = Ctx.getAsArrayType(BaseType)->getElementType();
  else
    BaseType = BaseType->castAs<PointerType>()->getPointeeType();
}

for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
  const auto &Entry = LVal.Designator.Entries[I];
  if (BaseType->isArrayType()) {
    // Because __builtin_object_size treats arrays as objects, we can ignore
    // the index iff this is the last array in the Designator.
    if (I + 1 == E)
      return true;
    const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
    uint64_t Index = Entry.getAsArrayIndex();
    if (Index + 1 != CAT->getSize())
      return false;
    BaseType = CAT->getElementType();
  } else if (BaseType->isAnyComplexType()) {
    const auto *CT = BaseType->castAs<ComplexType>();
    uint64_t Index = Entry.getAsArrayIndex();
    if (Index != 1)
      return false;
    BaseType = CT->getElementType();
  } else if (auto *FD = getAsField(Entry)) {
    bool Invalid;
    if (!IsLastOrInvalidFieldDecl(FD, Invalid))
      return Invalid;
    BaseType = FD->getType();
  } else {
    assert(getAsBaseClass(Entry) && "Expecting cast to a base class")((void)0);
    return false;
  }
}
return true;
11301}

11303/// Tests to see if the LValue has a user-specified designator (that isn't
11304/// necessarily valid). Note that this always returns 'true' if the LValue has
11305/// an unsized array as its first designator entry, because there's currently no
11306/// way to tell if the user typed *foo or foo[0].
11307static bool refersToCompleteObject(const LValue &LVal) {
if (LVal.Designator.Invalid)
  return false;

if (!LVal.Designator.Entries.empty())
  return LVal.Designator.isMostDerivedAnUnsizedArray();

if (!LVal.InvalidBase)
  return true;

// If `E` is a MemberExpr, then the first part of the designator is hiding in
// the LValueBase.
const auto *E = LVal.Base.dyn_cast<const Expr *>();
return !E || !isa<MemberExpr>(E);
11321}

11323/// Attempts to detect a user writing into a piece of memory that's impossible
11324/// to figure out the size of by just using types.
11325static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
const SubobjectDesignator &Designator = LVal.Designator;
// Notes:
// - Users can only write off of the end when we have an invalid base. Invalid
//   bases imply we don't know where the memory came from.
// - We used to be a bit more aggressive here; we'd only be conservative if
//   the array at the end was flexible, or if it had 0 or 1 elements. This
//   broke some common standard library extensions (PR30346), but was
//   otherwise seemingly fine. It may be useful to reintroduce this behavior
//   with some sort of list. OTOH, it seems that GCC is always
//   conservative with the last element in structs (if it's an array), so our
//   current behavior is more compatible than an explicit list approach would
//   be.
return LVal.InvalidBase &&
       Designator.Entries.size() == Designator.MostDerivedPathLength &&
       Designator.MostDerivedIsArrayElement &&
       isDesignatorAtObjectEnd(Ctx, LVal);
11342}

11344/// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
11345/// Fails if the conversion would cause loss of precision.
11346static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
                                          CharUnits &Result) {
auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
if (Int.ugt(CharUnitsMax))
  return false;
Result = CharUnits::fromQuantity(Int.getZExtValue());
return true;
11353}

11355/// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
11356/// determine how many bytes exist from the beginning of the object to either
11357/// the end of the current subobject, or the end of the object itself, depending
11358/// on what the LValue looks like + the value of Type.
11359///
11360/// If this returns false, the value of Result is undefined.
11361static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
                             unsigned Type, const LValue &LVal,
                             CharUnits &EndOffset) {
bool DetermineForCompleteObject = refersToCompleteObject(LVal);

auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
  if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
    return false;
  return HandleSizeof(Info, ExprLoc, Ty, Result);
};

// We want to evaluate the size of the entire object. This is a valid fallback
// for when Type=1 and the designator is invalid, because we're asked for an
// upper-bound.
if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
  // Type=3 wants a lower bound, so we can't fall back to this.
  if (Type == 3 && !DetermineForCompleteObject)
    return false;

  llvm::APInt APEndOffset;
  if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
      getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
    return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);

  if (LVal.InvalidBase)
    return false;

  QualType BaseTy = getObjectType(LVal.getLValueBase());
  return CheckedHandleSizeof(BaseTy, EndOffset);
}

// We want to evaluate the size of a subobject.
const SubobjectDesignator &Designator = LVal.Designator;

// The following is a moderately common idiom in C:
//
// struct Foo { int a; char c[1]; };
// struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
// strcpy(&F->c[0], Bar);
//
// In order to not break too much legacy code, we need to support it.
if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
  // If we can resolve this to an alloc_size call, we can hand that back,
  // because we know for certain how many bytes there are to write to.
  llvm::APInt APEndOffset;
  if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
      getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
    return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);

  // If we cannot determine the size of the initial allocation, then we can't
  // given an accurate upper-bound. However, we are still able to give
  // conservative lower-bounds for Type=3.
  if (Type == 1)
    return false;
}

CharUnits BytesPerElem;
if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
  return false;

// According to the GCC documentation, we want the size of the subobject
// denoted by the pointer. But that's not quite right -- what we actually
// want is the size of the immediately-enclosing array, if there is one.
int64_t ElemsRemaining;
if (Designator.MostDerivedIsArrayElement &&
    Designator.Entries.size() == Designator.MostDerivedPathLength) {
  uint64_t ArraySize = Designator.getMostDerivedArraySize();
  uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex();
  ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
} else {
  ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
}

EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
return true;
11436}

11438/// Tries to evaluate the __builtin_object_size for @p E. If successful,
11439/// returns true and stores the result in @p Size.
11440///
11441/// If @p WasError is non-null, this will report whether the failure to evaluate
11442/// is to be treated as an Error in IntExprEvaluator.
11443static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
                                       EvalInfo &Info, uint64_t &Size) {
// Determine the denoted object.
LValue LVal;
{
  // The operand of __builtin_object_size is never evaluated for side-effects.
  // If there are any, but we can determine the pointed-to object anyway, then
  // ignore the side-effects.
  SpeculativeEvaluationRAII SpeculativeEval(Info);
  IgnoreSideEffectsRAII Fold(Info);

  if (E->isGLValue()) {
    // It's possible for us to be given GLValues if we're called via
    // Expr::tryEvaluateObjectSize.
    APValue RVal;
    if (!EvaluateAsRValue(Info, E, RVal))
      return false;
    LVal.setFrom(Info.Ctx, RVal);
  } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info,
                              /*InvalidBaseOK=*/true))
    return false;
}

// If we point to before the start of the object, there are no accessible
// bytes.
if (LVal.getLValueOffset().isNegative()) {
  Size = 0;
  return true;
}

CharUnits EndOffset;
if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
  return false;

// If we've fallen outside of the end offset, just pretend there's nothing to
// write to/read from.
if (EndOffset <= LVal.getLValueOffset())
  Size = 0;
else
  Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
return true;
11484}

11486bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
if (unsigned BuiltinOp = E->getBuiltinCallee())
  return VisitBuiltinCallExpr(E, BuiltinOp);

return ExprEvaluatorBaseTy::VisitCallExpr(E);
11491}

11493static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info,
                                   APValue &Val, APSInt &Alignment) {
QualType SrcTy = E->getArg(0)->getType();
if (!getAlignmentArgument(E->getArg(1), SrcTy, Info, Alignment))
  return false;
// Even though we are evaluating integer expressions we could get a pointer
// argument for the __builtin_is_aligned() case.
if (SrcTy->isPointerType()) {
  LValue Ptr;
  if (!EvaluatePointer(E->getArg(0), Ptr, Info))
    return false;
  Ptr.moveInto(Val);
} else if (!SrcTy->isIntegralOrEnumerationType()) {
  Info.FFDiag(E->getArg(0));
  return false;
} else {
  APSInt SrcInt;
  if (!EvaluateInteger(E->getArg(0), SrcInt, Info))
    return false;
  assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() &&((void)0)
         "Bit widths must be the same")((void)0);
  Val = APValue(SrcInt);
}
assert(Val.hasValue())((void)0);
return true;
11518}

11520bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
                                          unsigned BuiltinOp) {
switch (BuiltinOp) {
default:
  return ExprEvaluatorBaseTy::VisitCallExpr(E);

case Builtin::BI__builtin_dynamic_object_size:
case Builtin::BI__builtin_object_size: {
  // The type was checked when we built the expression.
  unsigned Type =
      E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
  assert(Type <= 3 && "unexpected type")((void)0);

  uint64_t Size;
  if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
    return Success(Size, E);

  if (E->getArg(0)->HasSideEffects(Info.Ctx))
    return Success((Type & 2) ? 0 : -1, E);

  // Expression had no side effects, but we couldn't statically determine the
  // size of the referenced object.
  switch (Info.EvalMode) {
  case EvalInfo::EM_ConstantExpression:
  case EvalInfo::EM_ConstantFold:
  case EvalInfo::EM_IgnoreSideEffects:
    // Leave it to IR generation.
    return Error(E);
  case EvalInfo::EM_ConstantExpressionUnevaluated:
    // Reduce it to a constant now.
    return Success((Type & 2) ? 0 : -1, E);
  }

  llvm_unreachable("unexpected EvalMode")__builtin_unreachable();
}

case Builtin::BI__builtin_os_log_format_buffer_size: {
  analyze_os_log::OSLogBufferLayout Layout;
  analyze_os_log::computeOSLogBufferLayout(Info.Ctx, E, Layout);
  return Success(Layout.size().getQuantity(), E);
}

case Builtin::BI__builtin_is_aligned: {
  APValue Src;
  APSInt Alignment;
  if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
    return false;
  if (Src.isLValue()) {
    // If we evaluated a pointer, check the minimum known alignment.
    LValue Ptr;
    Ptr.setFrom(Info.Ctx, Src);
    CharUnits BaseAlignment = getBaseAlignment(Info, Ptr);
    CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Ptr.Offset);
    // We can return true if the known alignment at the computed offset is
    // greater than the requested alignment.
    assert(PtrAlign.isPowerOfTwo())((void)0);
    assert(Alignment.isPowerOf2())((void)0);
    if (PtrAlign.getQuantity() >= Alignment)
      return Success(1, E);
    // If the alignment is not known to be sufficient, some cases could still
    // be aligned at run time. However, if the requested alignment is less or
    // equal to the base alignment and the offset is not aligned, we know that
    // the run-time value can never be aligned.
    if (BaseAlignment.getQuantity() >= Alignment &&
        PtrAlign.getQuantity() < Alignment)
      return Success(0, E);
    // Otherwise we can't infer whether the value is sufficiently aligned.
    // TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N)
    //  in cases where we can't fully evaluate the pointer.
    Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_compute)
        << Alignment;
    return false;
  }
  assert(Src.isInt())((void)0);
  return Success((Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E);
}
case Builtin::BI__builtin_align_up: {
  APValue Src;
  APSInt Alignment;
  if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
    return false;
  if (!Src.isInt())
    return Error(E);
  APSInt AlignedVal =
      APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1),
             Src.getInt().isUnsigned());
  assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth())((void)0);
  return Success(AlignedVal, E);
}
case Builtin::BI__builtin_align_down: {
  APValue Src;
  APSInt Alignment;
  if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
    return false;
  if (!Src.isInt())
    return Error(E);
  APSInt AlignedVal =
      APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned());
  assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth())((void)0);
  return Success(AlignedVal, E);
}

case Builtin::BI__builtin_bitreverse8:
case Builtin::BI__builtin_bitreverse16:
case Builtin::BI__builtin_bitreverse32:
case Builtin::BI__builtin_bitreverse64: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;

  return Success(Val.reverseBits(), E);
}

case Builtin::BI__builtin_bswap16:
case Builtin::BI__builtin_bswap32:
case Builtin::BI__builtin_bswap64: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;

  return Success(Val.byteSwap(), E);
}

case Builtin::BI__builtin_classify_type:
  return Success((int)EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);

case Builtin::BI__builtin_clrsb:
case Builtin::BI__builtin_clrsbl:
case Builtin::BI__builtin_clrsbll: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;

  return Success(Val.getBitWidth() - Val.getMinSignedBits(), E);
}

case Builtin::BI__builtin_clz:
case Builtin::BI__builtin_clzl:
case Builtin::BI__builtin_clzll:
case Builtin::BI__builtin_clzs: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;
  if (!Val)
    return Error(E);

  return Success(Val.countLeadingZeros(), E);
}

case Builtin::BI__builtin_constant_p: {
  const Expr *Arg = E->getArg(0);
  if (EvaluateBuiltinConstantP(Info, Arg))
    return Success(true, E);
  if (Info.InConstantContext || Arg->HasSideEffects(Info.Ctx)) {
    // Outside a constant context, eagerly evaluate to false in the presence
    // of side-effects in order to avoid -Wunsequenced false-positives in
    // a branch on __builtin_constant_p(expr).
    return Success(false, E);
  }
  Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
  return false;
}

case Builtin::BI__builtin_is_constant_evaluated: {
  const auto *Callee = Info.CurrentCall->getCallee();
  if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression &&
      (Info.CallStackDepth == 1 ||
       (Info.CallStackDepth == 2 && Callee->isInStdNamespace() &&
        Callee->getIdentifier() &&
        Callee->getIdentifier()->isStr("is_constant_evaluated")))) {
    // FIXME: Find a better way to avoid duplicated diagnostics.
    if (Info.EvalStatus.Diag)
      Info.report((Info.CallStackDepth == 1) ? E->getExprLoc()
                                             : Info.CurrentCall->CallLoc,
                  diag::warn_is_constant_evaluated_always_true_constexpr)
          << (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated"
                                       : "std::is_constant_evaluated");
  }

  return Success(Info.InConstantContext, E);
}

case Builtin::BI__builtin_ctz:
case Builtin::BI__builtin_ctzl:
case Builtin::BI__builtin_ctzll:
case Builtin::BI__builtin_ctzs: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;
  if (!Val)
    return Error(E);

  return Success(Val.countTrailingZeros(), E);
}

case Builtin::BI__builtin_eh_return_data_regno: {
  int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
  Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
  return Success(Operand, E);
}

case Builtin::BI__builtin_expect:
case Builtin::BI__builtin_expect_with_probability:
  return Visit(E->getArg(0));

case Builtin::BI__builtin_ffs:
case Builtin::BI__builtin_ffsl:
case Builtin::BI__builtin_ffsll: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;

  unsigned N = Val.countTrailingZeros();
  return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
}

case Builtin::BI__builtin_fpclassify: {
  APFloat Val(0.0);
  if (!EvaluateFloat(E->getArg(5), Val, Info))
    return false;
  unsigned Arg;
  switch (Val.getCategory()) {
  case APFloat::fcNaN: Arg = 0; break;
  case APFloat::fcInfinity: Arg = 1; break;
  case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
  case APFloat::fcZero: Arg = 4; break;
  }
  return Visit(E->getArg(Arg));
}

case Builtin::BI__builtin_isinf_sign: {
  APFloat Val(0.0);
  return EvaluateFloat(E->getArg(0), Val, Info) &&
         Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
}

case Builtin::BI__builtin_isinf: {
  APFloat Val(0.0);
  return EvaluateFloat(E->getArg(0), Val, Info) &&
         Success(Val.isInfinity() ? 1 : 0, E);
}

case Builtin::BI__builtin_isfinite: {
  APFloat Val(0.0);
  return EvaluateFloat(E->getArg(0), Val, Info) &&
         Success(Val.isFinite() ? 1 : 0, E);
}

case Builtin::BI__builtin_isnan: {
  APFloat Val(0.0);
  return EvaluateFloat(E->getArg(0), Val, Info) &&
         Success(Val.isNaN() ? 1 : 0, E);
}

case Builtin::BI__builtin_isnormal: {
  APFloat Val(0.0);
  return EvaluateFloat(E->getArg(0), Val, Info) &&
         Success(Val.isNormal() ? 1 : 0, E);
}

case Builtin::BI__builtin_parity:
case Builtin::BI__builtin_parityl:
case Builtin::BI__builtin_parityll: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;

  return Success(Val.countPopulation() % 2, E);
}

case Builtin::BI__builtin_popcount:
case Builtin::BI__builtin_popcountl:
case Builtin::BI__builtin_popcountll: {
  APSInt Val;
  if (!EvaluateInteger(E->getArg(0), Val, Info))
    return false;

  return Success(Val.countPopulation(), E);
}

case Builtin::BI__builtin_rotateleft8:
case Builtin::BI__builtin_rotateleft16:
case Builtin::BI__builtin_rotateleft32:
case Builtin::BI__builtin_rotateleft64:
case Builtin::BI_rotl8: // Microsoft variants of rotate right
case Builtin::BI_rotl16:
case Builtin::BI_rotl:
case Builtin::BI_lrotl:
case Builtin::BI_rotl64: {
  APSInt Val, Amt;
  if (!EvaluateInteger(E->getArg(0), Val, Info) ||
      !EvaluateInteger(E->getArg(1), Amt, Info))
    return false;

  return Success(Val.rotl(Amt.urem(Val.getBitWidth())), E);
}

case Builtin::BI__builtin_rotateright8:
case Builtin::BI__builtin_rotateright16:
case Builtin::BI__builtin_rotateright32:
case Builtin::BI__builtin_rotateright64:
case Builtin::BI_rotr8: // Microsoft variants of rotate right
case Builtin::BI_rotr16:
case Builtin::BI_rotr:
case Builtin::BI_lrotr:
case Builtin::BI_rotr64: {
  APSInt Val, Amt;
  if (!EvaluateInteger(E->getArg(0), Val, Info) ||
      !EvaluateInteger(E->getArg(1), Amt, Info))
    return false;

  return Success(Val.rotr(Amt.urem(Val.getBitWidth())), E);
}

case Builtin::BIstrlen:
case Builtin::BIwcslen:
  // A call to strlen is not a constant expression.
  if (Info.getLangOpts().CPlusPlus11)
    Info.CCEDiag(E, diag::note_constexpr_invalid_function)
      << /*isConstexpr*/0 << /*isConstructor*/0
      << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
  else
    Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case Builtin::BI__builtin_strlen:
case Builtin::BI__builtin_wcslen: {
  // As an extension, we support __builtin_strlen() as a constant expression,
  // and support folding strlen() to a constant.
  LValue String;
  if (!EvaluatePointer(E->getArg(0), String, Info))
    return false;

  QualType CharTy = E->getArg(0)->getType()->getPointeeType();

  // Fast path: if it's a string literal, search the string value.
  if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
          String.getLValueBase().dyn_cast<const Expr *>())) {
    // The string literal may have embedded null characters. Find the first
    // one and truncate there.
    StringRef Str = S->getBytes();
    int64_t Off = String.Offset.getQuantity();
    if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
        S->getCharByteWidth() == 1 &&
        // FIXME: Add fast-path for wchar_t too.
        Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
      Str = Str.substr(Off);

      StringRef::size_type Pos = Str.find(0);
      if (Pos != StringRef::npos)
        Str = Str.substr(0, Pos);

      return Success(Str.size(), E);
    }

    // Fall through to slow path to issue appropriate diagnostic.
  }

  // Slow path: scan the bytes of the string looking for the terminating 0.
  for (uint64_t Strlen = 0; /**/; ++Strlen) {
    APValue Char;
    if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
        !Char.isInt())
      return false;
    if (!Char.getInt())
      return Success(Strlen, E);
    if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
      return false;
  }
}

case Builtin::BIstrcmp:
case Builtin::BIwcscmp:
case Builtin::BIstrncmp:
case Builtin::BIwcsncmp:
case Builtin::BImemcmp:
case Builtin::BIbcmp:
case Builtin::BIwmemcmp:
  // A call to strlen is not a constant expression.
  if (Info.getLangOpts().CPlusPlus11)
    Info.CCEDiag(E, diag::note_constexpr_invalid_function)
      << /*isConstexpr*/0 << /*isConstructor*/0
      << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
  else
    Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case Builtin::BI__builtin_strcmp:
case Builtin::BI__builtin_wcscmp:
case Builtin::BI__builtin_strncmp:
case Builtin::BI__builtin_wcsncmp:
case Builtin::BI__builtin_memcmp:
case Builtin::BI__builtin_bcmp:
case Builtin::BI__builtin_wmemcmp: {
  LValue String1, String2;
  if (!EvaluatePointer(E->getArg(0), String1, Info) ||
      !EvaluatePointer(E->getArg(1), String2, Info))
    return false;

  uint64_t MaxLength = uint64_t(-1);
  if (BuiltinOp != Builtin::BIstrcmp &&
      BuiltinOp != Builtin::BIwcscmp &&
      BuiltinOp != Builtin::BI__builtin_strcmp &&
      BuiltinOp != Builtin::BI__builtin_wcscmp) {
    APSInt N;
    if (!EvaluateInteger(E->getArg(2), N, Info))
      return false;
    MaxLength = N.getExtValue();
  }

  // Empty substrings compare equal by definition.
  if (MaxLength == 0u)
    return Success(0, E);

  if (!String1.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
      !String2.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
      String1.Designator.Invalid || String2.Designator.Invalid)
    return false;

  QualType CharTy1 = String1.Designator.getType(Info.Ctx);
  QualType CharTy2 = String2.Designator.getType(Info.Ctx);

  bool IsRawByte = BuiltinOp == Builtin::BImemcmp ||
                   BuiltinOp == Builtin::BIbcmp ||
                   BuiltinOp == Builtin::BI__builtin_memcmp ||
                   BuiltinOp == Builtin::BI__builtin_bcmp;

  assert(IsRawByte ||((void)0)
         (Info.Ctx.hasSameUnqualifiedType(((void)0)
              CharTy1, E->getArg(0)->getType()->getPointeeType()) &&((void)0)
          Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2)))((void)0);

  // For memcmp, allow comparing any arrays of '[[un]signed] char' or
  // 'char8_t', but no other types.
  if (IsRawByte &&
      !(isOneByteCharacterType(CharTy1) && isOneByteCharacterType(CharTy2))) {
    // FIXME: Consider using our bit_cast implementation to support this.
    Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported)
        << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
        << CharTy1 << CharTy2;
    return false;
  }

  const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) {
    return handleLValueToRValueConversion(Info, E, CharTy1, String1, Char1) &&
           handleLValueToRValueConversion(Info, E, CharTy2, String2, Char2) &&
           Char1.isInt() && Char2.isInt();
  };
  const auto &AdvanceElems = [&] {
    return HandleLValueArrayAdjustment(Info, E, String1, CharTy1, 1) &&
           HandleLValueArrayAdjustment(Info, E, String2, CharTy2, 1);
  };

  bool StopAtNull =
      (BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp &&
       BuiltinOp != Builtin::BIwmemcmp &&
       BuiltinOp != Builtin::BI__builtin_memcmp &&
       BuiltinOp != Builtin::BI__builtin_bcmp &&
       BuiltinOp != Builtin::BI__builtin_wmemcmp);
  bool IsWide = BuiltinOp == Builtin::BIwcscmp ||
                BuiltinOp == Builtin::BIwcsncmp ||
                BuiltinOp == Builtin::BIwmemcmp ||
                BuiltinOp == Builtin::BI__builtin_wcscmp ||
                BuiltinOp == Builtin::BI__builtin_wcsncmp ||
                BuiltinOp == Builtin::BI__builtin_wmemcmp;

  for (; MaxLength; --MaxLength) {
    APValue Char1, Char2;
    if (!ReadCurElems(Char1, Char2))
      return false;
    if (Char1.getInt().ne(Char2.getInt())) {
      if (IsWide) // wmemcmp compares with wchar_t signedness.
        return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
      // memcmp always compares unsigned chars.
      return Success(Char1.getInt().ult(Char2.getInt()) ? -1 : 1, E);
    }
    if (StopAtNull && !Char1.getInt())
      return Success(0, E);
    assert(!(StopAtNull && !Char2.getInt()))((void)0);
    if (!AdvanceElems())
      return false;
  }
  // We hit the strncmp / memcmp limit.
  return Success(0, E);
}

case Builtin::BI__atomic_always_lock_free:
case Builtin::BI__atomic_is_lock_free:
case Builtin::BI__c11_atomic_is_lock_free: {
  APSInt SizeVal;
  if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
    return false;

  // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
  // of two less than or equal to the maximum inline atomic width, we know it
  // is lock-free.  If the size isn't a power of two, or greater than the
  // maximum alignment where we promote atomics, we know it is not lock-free
  // (at least not in the sense of atomic_is_lock_free).  Otherwise,
  // the answer can only be determined at runtime; for example, 16-byte
  // atomics have lock-free implementations on some, but not all,
  // x86-64 processors.

  // Check power-of-two.
  CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
  if (Size.isPowerOfTwo()) {
    // Check against inlining width.
    unsigned InlineWidthBits =
        Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
    if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
      if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
          Size == CharUnits::One() ||
          E->getArg(1)->isNullPointerConstant(Info.Ctx,
                                              Expr::NPC_NeverValueDependent))
        // OK, we will inline appropriately-aligned operations of this size,
        // and _Atomic(T) is appropriately-aligned.
        return Success(1, E);

      QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
        castAs<PointerType>()->getPointeeType();
      if (!PointeeType->isIncompleteType() &&
          Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
        // OK, we will inline operations on this object.
        return Success(1, E);
      }
    }
  }

  return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
      Success(0, E) : Error(E);
}
case Builtin::BI__builtin_add_overflow:
case Builtin::BI__builtin_sub_overflow:
case Builtin::BI__builtin_mul_overflow:
case Builtin::BI__builtin_sadd_overflow:
case Builtin::BI__builtin_uadd_overflow:
case Builtin::BI__builtin_uaddl_overflow:
case Builtin::BI__builtin_uaddll_overflow:
case Builtin::BI__builtin_usub_overflow:
case Builtin::BI__builtin_usubl_overflow:
case Builtin::BI__builtin_usubll_overflow:
case Builtin::BI__builtin_umul_overflow:
case Builtin::BI__builtin_umull_overflow:
case Builtin::BI__builtin_umulll_overflow:
case Builtin::BI__builtin_saddl_overflow:
case Builtin::BI__builtin_saddll_overflow:
case Builtin::BI__builtin_ssub_overflow:
case Builtin::BI__builtin_ssubl_overflow:
case Builtin::BI__builtin_ssubll_overflow:
case Builtin::BI__builtin_smul_overflow:
case Builtin::BI__builtin_smull_overflow:
case Builtin::BI__builtin_smulll_overflow: {
  LValue ResultLValue;
  APSInt LHS, RHS;

  QualType ResultType = E->getArg(2)->getType()->getPointeeType();
  if (!EvaluateInteger(E->getArg(0), LHS, Info) ||
      !EvaluateInteger(E->getArg(1), RHS, Info) ||
      !EvaluatePointer(E->getArg(2), ResultLValue, Info))
    return false;

  APSInt Result;
  bool DidOverflow = false;

  // If the types don't have to match, enlarge all 3 to the largest of them.
  if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
      BuiltinOp == Builtin::BI__builtin_sub_overflow ||
      BuiltinOp == Builtin::BI__builtin_mul_overflow) {
    bool IsSigned = LHS.isSigned() || RHS.isSigned() ||
                    ResultType->isSignedIntegerOrEnumerationType();
    bool AllSigned = LHS.isSigned() && RHS.isSigned() &&
                    ResultType->isSignedIntegerOrEnumerationType();
    uint64_t LHSSize = LHS.getBitWidth();
    uint64_t RHSSize = RHS.getBitWidth();
    uint64_t ResultSize = Info.Ctx.getTypeSize(ResultType);
    uint64_t MaxBits = std::max(std::max(LHSSize, RHSSize), ResultSize);

    // Add an additional bit if the signedness isn't uniformly agreed to. We
    // could do this ONLY if there is a signed and an unsigned that both have
    // MaxBits, but the code to check that is pretty nasty.  The issue will be
    // caught in the shrink-to-result later anyway.
    if (IsSigned && !AllSigned)
      ++MaxBits;

    LHS = APSInt(LHS.extOrTrunc(MaxBits), !IsSigned);
    RHS = APSInt(RHS.extOrTrunc(MaxBits), !IsSigned);
    Result = APSInt(MaxBits, !IsSigned);
  }

  // Find largest int.
  switch (BuiltinOp) {
  default:
    llvm_unreachable("Invalid value for BuiltinOp")__builtin_unreachable();
  case Builtin::BI__builtin_add_overflow:
  case Builtin::BI__builtin_sadd_overflow:
  case Builtin::BI__builtin_saddl_overflow:
  case Builtin::BI__builtin_saddll_overflow:
  case Builtin::BI__builtin_uadd_overflow:
  case Builtin::BI__builtin_uaddl_overflow:
  case Builtin::BI__builtin_uaddll_overflow:
    Result = LHS.isSigned() ? LHS.sadd_ov(RHS, DidOverflow)
                            : LHS.uadd_ov(RHS, DidOverflow);
    break;
  case Builtin::BI__builtin_sub_overflow:
  case Builtin::BI__builtin_ssub_overflow:
  case Builtin::BI__builtin_ssubl_overflow:
  case Builtin::BI__builtin_ssubll_overflow:
  case Builtin::BI__builtin_usub_overflow:
  case Builtin::BI__builtin_usubl_overflow:
  case Builtin::BI__builtin_usubll_overflow:
    Result = LHS.isSigned() ? LHS.ssub_ov(RHS, DidOverflow)
                            : LHS.usub_ov(RHS, DidOverflow);
    break;
  case Builtin::BI__builtin_mul_overflow:
  case Builtin::BI__builtin_smul_overflow:
  case Builtin::BI__builtin_smull_overflow:
  case Builtin::BI__builtin_smulll_overflow:
  case Builtin::BI__builtin_umul_overflow:
  case Builtin::BI__builtin_umull_overflow:
  case Builtin::BI__builtin_umulll_overflow:
    Result = LHS.isSigned() ? LHS.smul_ov(RHS, DidOverflow)
                            : LHS.umul_ov(RHS, DidOverflow);
    break;
  }

  // In the case where multiple sizes are allowed, truncate and see if
  // the values are the same.
  if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
      BuiltinOp == Builtin::BI__builtin_sub_overflow ||
      BuiltinOp == Builtin::BI__builtin_mul_overflow) {
    // APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead,
    // since it will give us the behavior of a TruncOrSelf in the case where
    // its parameter <= its size.  We previously set Result to be at least the
    // type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth
    // will work exactly like TruncOrSelf.
    APSInt Temp = Result.extOrTrunc(Info.Ctx.getTypeSize(ResultType));
    Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType());

    if (!APSInt::isSameValue(Temp, Result))
      DidOverflow = true;
    Result = Temp;
  }

  APValue APV{Result};
  if (!handleAssignment(Info, E, ResultLValue, ResultType, APV))
    return false;
  return Success(DidOverflow, E);
}
}
12166}

12168/// Determine whether this is a pointer past the end of the complete
12169/// object referred to by the lvalue.
12170static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
                                          const LValue &LV) {
// A null pointer can be viewed as being "past the end" but we don't
// choose to look at it that way here.
if (!LV.getLValueBase())
  return false;

// If the designator is valid and refers to a subobject, we're not pointing
// past the end.
if (!LV.getLValueDesignator().Invalid &&
    !LV.getLValueDesignator().isOnePastTheEnd())
  return false;

// A pointer to an incomplete type might be past-the-end if the type's size is
// zero.  We cannot tell because the type is incomplete.
QualType Ty = getType(LV.getLValueBase());
if (Ty->isIncompleteType())
  return true;

// We're a past-the-end pointer if we point to the byte after the object,
// no matter what our type or path is.
auto Size = Ctx.getTypeSizeInChars(Ty);
return LV.getLValueOffset() == Size;
12193}

12195namespace {

12197/// Data recursive integer evaluator of certain binary operators.
12198///
12199/// We use a data recursive algorithm for binary operators so that we are able
12200/// to handle extreme cases of chained binary operators without causing stack
12201/// overflow.
12202class DataRecursiveIntBinOpEvaluator {
struct EvalResult {
  APValue Val;
  bool Failed;

  EvalResult() : Failed(false) { }

  void swap(EvalResult &RHS) {
    Val.swap(RHS.Val);
    Failed = RHS.Failed;
    RHS.Failed = false;
  }
};

struct Job {
  const Expr *E;
  EvalResult LHSResult; // meaningful only for binary operator expression.
  enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;

  Job() = default;
  Job(Job &&) = default;

  void startSpeculativeEval(EvalInfo &Info) {
    SpecEvalRAII = SpeculativeEvaluationRAII(Info);
  }

private:
  SpeculativeEvaluationRAII SpecEvalRAII;
};

SmallVector<Job, 16> Queue;

IntExprEvaluator &IntEval;
EvalInfo &Info;
APValue &FinalResult;

12238public:
DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
  : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }

/// True if \param E is a binary operator that we are going to handle
/// data recursively.
/// We handle binary operators that are comma, logical, or that have operands
/// with integral or enumeration type.
static bool shouldEnqueue(const BinaryOperator *E) {
  return E->getOpcode() == BO_Comma || E->isLogicalOp() ||
         (E->isPRValue() && E->getType()->isIntegralOrEnumerationType() &&
          E->getLHS()->getType()->isIntegralOrEnumerationType() &&
          E->getRHS()->getType()->isIntegralOrEnumerationType());
}

bool Traverse(const BinaryOperator *E) {
  enqueue(E);
  EvalResult PrevResult;
  while (!Queue.empty())
    process(PrevResult);

  if (PrevResult.Failed) return false;

  FinalResult.swap(PrevResult.Val);
  return true;
}

12265private:
bool Success(uint64_t Value, const Expr *E, APValue &Result) {
  return IntEval.Success(Value, E, Result);
}
bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
  return IntEval.Success(Value, E, Result);
}
bool Error(const Expr *E) {
  return IntEval.Error(E);
}
bool Error(const Expr *E, diag::kind D) {
  return IntEval.Error(E, D);
}

OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
  return Info.CCEDiag(E, D);
}

// Returns true if visiting the RHS is necessary, false otherwise.
bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
                       bool &SuppressRHSDiags);

bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
                const BinaryOperator *E, APValue &Result);

void EvaluateExpr(const Expr *E, EvalResult &Result) {
  Result.Failed = !Evaluate(Result.Val, Info, E);
  if (Result.Failed)
    Result.Val = APValue();
}

void process(EvalResult &Result);

void enqueue(const Expr *E) {
  E = E->IgnoreParens();
  Queue.resize(Queue.size()+1);
  Queue.back().E = E;
  Queue.back().Kind = Job::AnyExprKind;
}
12304};

12306}

12308bool DataRecursiveIntBinOpEvaluator::
     VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
                       bool &SuppressRHSDiags) {
if (E->getOpcode() == BO_Comma) {
  // Ignore LHS but note if we could not evaluate it.
  if (LHSResult.Failed)
    return Info.noteSideEffect();
  return true;
}

if (E->isLogicalOp()) {
  bool LHSAsBool;
  if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) {
    // We were able to evaluate the LHS, see if we can get away with not
    // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
    if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
      Success(LHSAsBool, E, LHSResult.Val);
      return false; // Ignore RHS
    }
  } else {
    LHSResult.Failed = true;

    // Since we weren't able to evaluate the left hand side, it
    // might have had side effects.
    if (!Info.noteSideEffect())
      return false;

    // We can't evaluate the LHS; however, sometimes the result
    // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
    // Don't ignore RHS and suppress diagnostics from this arm.
    SuppressRHSDiags = true;
  }

  return true;
}

assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&((void)0)
       E->getRHS()->getType()->isIntegralOrEnumerationType())((void)0);

if (LHSResult.Failed && !Info.noteFailure())
  return false; // Ignore RHS;

return true;
12351}

12353static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
                                  bool IsSub) {
// Compute the new offset in the appropriate width, wrapping at 64 bits.
// FIXME: When compiling for a 32-bit target, we should use 32-bit
// offsets.
assert(!LVal.hasLValuePath() && "have designator for integer lvalue")((void)0);
CharUnits &Offset = LVal.getLValueOffset();
uint64_t Offset64 = Offset.getQuantity();
uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64
                                       : Offset64 + Index64);
12364}

12366bool DataRecursiveIntBinOpEvaluator::
     VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
                const BinaryOperator *E, APValue &Result) {
if (E->getOpcode() == BO_Comma) {
  if (RHSResult.Failed)
    return false;
  Result = RHSResult.Val;
  return true;
}

if (E->isLogicalOp()) {
  bool lhsResult, rhsResult;
  bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
  bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);

  if (LHSIsOK) {
    if (RHSIsOK) {
      if (E->getOpcode() == BO_LOr)
        return Success(lhsResult || rhsResult, E, Result);
      else
        return Success(lhsResult && rhsResult, E, Result);
    }
  } else {
    if (RHSIsOK) {
      // We can't evaluate the LHS; however, sometimes the result
      // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
      if (rhsResult == (E->getOpcode() == BO_LOr))
        return Success(rhsResult, E, Result);
    }
  }

  return false;
}

assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&((void)0)
       E->getRHS()->getType()->isIntegralOrEnumerationType())((void)0);

if (LHSResult.Failed || RHSResult.Failed)
  return false;

const APValue &LHSVal = LHSResult.Val;
const APValue &RHSVal = RHSResult.Val;

// Handle cases like (unsigned long)&a + 4.
if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
  Result = LHSVal;
  addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub);
  return true;
}

// Handle cases like 4 + (unsigned long)&a
if (E->getOpcode() == BO_Add &&
    RHSVal.isLValue() && LHSVal.isInt()) {
  Result = RHSVal;
  addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false);
  return true;
}

if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
  // Handle (intptr_t)&&A - (intptr_t)&&B.
  if (!LHSVal.getLValueOffset().isZero() ||
      !RHSVal.getLValueOffset().isZero())
    return false;
  const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
  const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
  if (!LHSExpr || !RHSExpr)
    return false;
  const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
  const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
  if (!LHSAddrExpr || !RHSAddrExpr)
    return false;
  // Make sure both labels come from the same function.
  if (LHSAddrExpr->getLabel()->getDeclContext() !=
      RHSAddrExpr->getLabel()->getDeclContext())
    return false;
  Result = APValue(LHSAddrExpr, RHSAddrExpr);
  return true;
}

// All the remaining cases expect both operands to be an integer
if (!LHSVal.isInt() || !RHSVal.isInt())
  return Error(E);

// Set up the width and signedness manually, in case it can't be deduced
// from the operation we're performing.
// FIXME: Don't do this in the cases where we can deduce it.
APSInt Value(Info.Ctx.getIntWidth(E->getType()),
             E->getType()->isUnsignedIntegerOrEnumerationType());
if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(),
                       RHSVal.getInt(), Value))
  return false;
return Success(Value, E, Result);
12458}

12460void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
Job &job = Queue.back();

switch (job.Kind) {
  case Job::AnyExprKind: {
    if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
      if (shouldEnqueue(Bop)) {
        job.Kind = Job::BinOpKind;
        enqueue(Bop->getLHS());
        return;
      }
    }

    EvaluateExpr(job.E, Result);
    Queue.pop_back();
    return;
  }

  case Job::BinOpKind: {
    const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
    bool SuppressRHSDiags = false;
    if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
      Queue.pop_back();
      return;
    }
    if (SuppressRHSDiags)
      job.startSpeculativeEval(Info);
    job.LHSResult.swap(Result);
    job.Kind = Job::BinOpVisitedLHSKind;
    enqueue(Bop->getRHS());
    return;
  }

  case Job::BinOpVisitedLHSKind: {
    const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
    EvalResult RHS;
    RHS.swap(Result);
    Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
    Queue.pop_back();
    return;
  }
}

llvm_unreachable("Invalid Job::Kind!")__builtin_unreachable();
12504}

12506namespace {
12507enum class CmpResult {
Unequal,
Less,
Equal,
Greater,
Unordered,
12513};
12514}

12516template <class SuccessCB, class AfterCB>
12517static bool
12518EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E,
                               SuccessCB &&Success, AfterCB &&DoAfter) {
assert(!E->isValueDependent())((void)0);
assert(E->isComparisonOp() && "expected comparison operator")((void)0);
assert((E->getOpcode() == BO_Cmp ||((void)0)
        E->getType()->isIntegralOrEnumerationType()) &&((void)0)
       "unsupported binary expression evaluation")((void)0);
auto Error = [&](const Expr *E) {
  Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
  return false;
};

bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp;
bool IsEquality = E->isEqualityOp();

QualType LHSTy = E->getLHS()->getType();
QualType RHSTy = E->getRHS()->getType();

if (LHSTy->isIntegralOrEnumerationType() &&
    RHSTy->isIntegralOrEnumerationType()) {
  APSInt LHS, RHS;
  bool LHSOK = EvaluateInteger(E->getLHS(), LHS, Info);
  if (!LHSOK && !Info.noteFailure())
    return false;
  if (!EvaluateInteger(E->getRHS(), RHS, Info) || !LHSOK)
    return false;
  if (LHS < RHS)
    return Success(CmpResult::Less, E);
  if (LHS > RHS)
    return Success(CmpResult::Greater, E);
  return Success(CmpResult::Equal, E);
}

if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) {
  APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHSTy));
  APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHSTy));

  bool LHSOK = EvaluateFixedPointOrInteger(E->getLHS(), LHSFX, Info);
  if (!LHSOK && !Info.noteFailure())
    return false;
  if (!EvaluateFixedPointOrInteger(E->getRHS(), RHSFX, Info) || !LHSOK)
    return false;
  if (LHSFX < RHSFX)
    return Success(CmpResult::Less, E);
  if (LHSFX > RHSFX)
    return Success(CmpResult::Greater, E);
  return Success(CmpResult::Equal, E);
}

if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
  ComplexValue LHS, RHS;
  bool LHSOK;
  if (E->isAssignmentOp()) {
    LValue LV;
    EvaluateLValue(E->getLHS(), LV, Info);
    LHSOK = false;
  } else if (LHSTy->isRealFloatingType()) {
    LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info);
    if (LHSOK) {
      LHS.makeComplexFloat();
      LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
    }
  } else {
    LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
  }
  if (!LHSOK && !Info.noteFailure())
    return false;

  if (E->getRHS()->getType()->isRealFloatingType()) {
    if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK)
      return false;
    RHS.makeComplexFloat();
    RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
  } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
    return false;

  if (LHS.isComplexFloat()) {
    APFloat::cmpResult CR_r =
      LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
    APFloat::cmpResult CR_i =
      LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
    bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual;
    return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
  } else {
    assert(IsEquality && "invalid complex comparison")((void)0);
    bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
                   LHS.getComplexIntImag() == RHS.getComplexIntImag();
    return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
  }
}

if (LHSTy->isRealFloatingType() &&
    RHSTy->isRealFloatingType()) {
  APFloat RHS(0.0), LHS(0.0);

  bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
  if (!LHSOK && !Info.noteFailure())
    return false;

  if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
    return false;

  assert(E->isComparisonOp() && "Invalid binary operator!")((void)0);
  llvm::APFloatBase::cmpResult APFloatCmpResult = LHS.compare(RHS);
  if (!Info.InConstantContext &&
      APFloatCmpResult == APFloat::cmpUnordered &&
      E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).isFPConstrained()) {
    // Note: Compares may raise invalid in some cases involving NaN or sNaN.
    Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
    return false;
  }
  auto GetCmpRes = [&]() {
    switch (APFloatCmpResult) {
    case APFloat::cmpEqual:
      return CmpResult::Equal;
    case APFloat::cmpLessThan:
      return CmpResult::Less;
    case APFloat::cmpGreaterThan:
      return CmpResult::Greater;
    case APFloat::cmpUnordered:
      return CmpResult::Unordered;
    }
    llvm_unreachable("Unrecognised APFloat::cmpResult enum")__builtin_unreachable();
  };
  return Success(GetCmpRes(), E);
}

if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
  LValue LHSValue, RHSValue;

  bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
  if (!LHSOK && !Info.noteFailure())
    return false;

  if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
    return false;

  // Reject differing bases from the normal codepath; we special-case
  // comparisons to null.
  if (!HasSameBase(LHSValue, RHSValue)) {
    // Inequalities and subtractions between unrelated pointers have
    // unspecified or undefined behavior.
    if (!IsEquality) {
      Info.FFDiag(E, diag::note_constexpr_pointer_comparison_unspecified);
      return false;
    }
    // A constant address may compare equal to the address of a symbol.
    // The one exception is that address of an object cannot compare equal
    // to a null pointer constant.
    if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
        (!RHSValue.Base && !RHSValue.Offset.isZero()))
      return Error(E);
    // It's implementation-defined whether distinct literals will have
    // distinct addresses. In clang, the result of such a comparison is
    // unspecified, so it is not a constant expression. However, we do know
    // that the address of a literal will be non-null.
    if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
        LHSValue.Base && RHSValue.Base)
      return Error(E);
    // We can't tell whether weak symbols will end up pointing to the same
    // object.
    if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
      return Error(E);
    // We can't compare the address of the start of one object with the
    // past-the-end address of another object, per C++ DR1652.
    if ((LHSValue.Base && LHSValue.Offset.isZero() &&
         isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) ||
        (RHSValue.Base && RHSValue.Offset.isZero() &&
         isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
      return Error(E);
    // We can't tell whether an object is at the same address as another
    // zero sized object.
    if ((RHSValue.Base && isZeroSized(LHSValue)) ||
        (LHSValue.Base && isZeroSized(RHSValue)))
      return Error(E);
    return Success(CmpResult::Unequal, E);
  }

  const CharUnits &LHSOffset = LHSValue.getLValueOffset();
  const CharUnits &RHSOffset = RHSValue.getLValueOffset();

  SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
  SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();

  // C++11 [expr.rel]p3:
  //   Pointers to void (after pointer conversions) can be compared, with a
  //   result defined as follows: If both pointers represent the same
  //   address or are both the null pointer value, the result is true if the
  //   operator is <= or >= and false otherwise; otherwise the result is
  //   unspecified.
  // We interpret this as applying to pointers to *cv* void.
  if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && IsRelational)
    Info.CCEDiag(E, diag::note_constexpr_void_comparison);

  // C++11 [expr.rel]p2:
  // - If two pointers point to non-static data members of the same object,
  //   or to subobjects or array elements fo such members, recursively, the
  //   pointer to the later declared member compares greater provided the
  //   two members have the same access control and provided their class is
  //   not a union.
  //   [...]
  // - Otherwise pointer comparisons are unspecified.
  if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) {
    bool WasArrayIndex;
    unsigned Mismatch = FindDesignatorMismatch(
        getType(LHSValue.Base), LHSDesignator, RHSDesignator, WasArrayIndex);
    // At the point where the designators diverge, the comparison has a
    // specified value if:
    //  - we are comparing array indices
    //  - we are comparing fields of a union, or fields with the same access
    // Otherwise, the result is unspecified and thus the comparison is not a
    // constant expression.
    if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
        Mismatch < RHSDesignator.Entries.size()) {
      const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
      const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
      if (!LF && !RF)
        Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
      else if (!LF)
        Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
            << getAsBaseClass(LHSDesignator.Entries[Mismatch])
            << RF->getParent() << RF;
      else if (!RF)
        Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
            << getAsBaseClass(RHSDesignator.Entries[Mismatch])
            << LF->getParent() << LF;
      else if (!LF->getParent()->isUnion() &&
               LF->getAccess() != RF->getAccess())
        Info.CCEDiag(E,
                     diag::note_constexpr_pointer_comparison_differing_access)
            << LF << LF->getAccess() << RF << RF->getAccess()
            << LF->getParent();
    }
  }

  // The comparison here must be unsigned, and performed with the same
  // width as the pointer.
  unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
  uint64_t CompareLHS = LHSOffset.getQuantity();
  uint64_t CompareRHS = RHSOffset.getQuantity();
  assert(PtrSize <= 64 && "Unexpected pointer width")((void)0);
  uint64_t Mask = ~0ULL >> (64 - PtrSize);
  CompareLHS &= Mask;
  CompareRHS &= Mask;

  // If there is a base and this is a relational operator, we can only
  // compare pointers within the object in question; otherwise, the result
  // depends on where the object is located in memory.
  if (!LHSValue.Base.isNull() && IsRelational) {
    QualType BaseTy = getType(LHSValue.Base);
    if (BaseTy->isIncompleteType())
      return Error(E);
    CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
    uint64_t OffsetLimit = Size.getQuantity();
    if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
      return Error(E);
  }

  if (CompareLHS < CompareRHS)
    return Success(CmpResult::Less, E);
  if (CompareLHS > CompareRHS)
    return Success(CmpResult::Greater, E);
  return Success(CmpResult::Equal, E);
}

if (LHSTy->isMemberPointerType()) {
  assert(IsEquality && "unexpected member pointer operation")((void)0);
  assert(RHSTy->isMemberPointerType() && "invalid comparison")((void)0);

  MemberPtr LHSValue, RHSValue;

  bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
  if (!LHSOK && !Info.noteFailure())
    return false;

  if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
    return false;

  // C++11 [expr.eq]p2:
  //   If both operands are null, they compare equal. Otherwise if only one is
  //   null, they compare unequal.
  if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
    bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
    return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
  }

  //   Otherwise if either is a pointer to a virtual member function, the
  //   result is unspecified.
  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
    if (MD->isVirtual())
      Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
    if (MD->isVirtual())
      Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;

  //   Otherwise they compare equal if and only if they would refer to the
  //   same member of the same most derived object or the same subobject if
  //   they were dereferenced with a hypothetical object of the associated
  //   class type.
  bool Equal = LHSValue == RHSValue;
  return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
}

if (LHSTy->isNullPtrType()) {
  assert(E->isComparisonOp() && "unexpected nullptr operation")((void)0);
  assert(RHSTy->isNullPtrType() && "missing pointer conversion")((void)0);
  // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
  // are compared, the result is true of the operator is <=, >= or ==, and
  // false otherwise.
  return Success(CmpResult::Equal, E);
}

return DoAfter();
12831}

12833bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) {
if (!CheckLiteralType(Info, E))
  return false;

auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
  ComparisonCategoryResult CCR;
  switch (CR) {
  case CmpResult::Unequal:
    llvm_unreachable("should never produce Unequal for three-way comparison")__builtin_unreachable();
  case CmpResult::Less:
    CCR = ComparisonCategoryResult::Less;
    break;
  case CmpResult::Equal:
    CCR = ComparisonCategoryResult::Equal;
    break;
  case CmpResult::Greater:
    CCR = ComparisonCategoryResult::Greater;
    break;
  case CmpResult::Unordered:
    CCR = ComparisonCategoryResult::Unordered;
    break;
  }
  // Evaluation succeeded. Lookup the information for the comparison category
  // type and fetch the VarDecl for the result.
  const ComparisonCategoryInfo &CmpInfo =
      Info.Ctx.CompCategories.getInfoForType(E->getType());
  const VarDecl *VD = CmpInfo.getValueInfo(CmpInfo.makeWeakResult(CCR))->VD;
  // Check and evaluate the result as a constant expression.
  LValue LV;
  LV.set(VD);
  if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
    return false;
  return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
                                 ConstantExprKind::Normal);
};
return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
  return ExprEvaluatorBaseTy::VisitBinCmp(E);
});
12871}

12873bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
// We don't support assignment in C. C++ assignments don't get here because
// assignment is an lvalue in C++.
if (E->isAssignmentOp()) {
  Error(E);
  if (!Info.noteFailure())
    return false;
}

if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
  return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);

assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() ||((void)0)
        !E->getRHS()->getType()->isIntegralOrEnumerationType()) &&((void)0)
       "DataRecursiveIntBinOpEvaluator should have handled integral types")((void)0);

if (E->isComparisonOp()) {
  // Evaluate builtin binary comparisons by evaluating them as three-way
  // comparisons and then translating the result.
  auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
    assert((CR != CmpResult::Unequal || E->isEqualityOp()) &&((void)0)
           "should only produce Unequal for equality comparisons")((void)0);
    bool IsEqual   = CR == CmpResult::Equal,
         IsLess    = CR == CmpResult::Less,
         IsGreater = CR == CmpResult::Greater;
    auto Op = E->getOpcode();
    switch (Op) {
    default:
      llvm_unreachable("unsupported binary operator")__builtin_unreachable();
    case BO_EQ:
    case BO_NE:
      return Success(IsEqual == (Op == BO_EQ), E);
    case BO_LT:
      return Success(IsLess, E);
    case BO_GT:
      return Success(IsGreater, E);
    case BO_LE:
      return Success(IsEqual || IsLess, E);
    case BO_GE:
      return Success(IsEqual || IsGreater, E);
    }
  };
  return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
    return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
  });
}

QualType LHSTy = E->getLHS()->getType();
QualType RHSTy = E->getRHS()->getType();

if (LHSTy->isPointerType() && RHSTy->isPointerType() &&
    E->getOpcode() == BO_Sub) {
  LValue LHSValue, RHSValue;

  bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
  if (!LHSOK && !Info.noteFailure())
    return false;

  if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
    return false;

  // Reject differing bases from the normal codepath; we special-case
  // comparisons to null.
  if (!HasSameBase(LHSValue, RHSValue)) {
    // Handle &&A - &&B.
    if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
      return Error(E);
    const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>();
    const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>();
    if (!LHSExpr || !RHSExpr)
      return Error(E);
    const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
    const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
    if (!LHSAddrExpr || !RHSAddrExpr)
      return Error(E);
    // Make sure both labels come from the same function.
    if (LHSAddrExpr->getLabel()->getDeclContext() !=
        RHSAddrExpr->getLabel()->getDeclContext())
      return Error(E);
    return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
  }
  const CharUnits &LHSOffset = LHSValue.getLValueOffset();
  const CharUnits &RHSOffset = RHSValue.getLValueOffset();

  SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
  SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();

  // C++11 [expr.add]p6:
  //   Unless both pointers point to elements of the same array object, or
  //   one past the last element of the array object, the behavior is
  //   undefined.
  if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
      !AreElementsOfSameArray(getType(LHSValue.Base), LHSDesignator,
                              RHSDesignator))
    Info.CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);

  QualType Type = E->getLHS()->getType();
  QualType ElementType = Type->castAs<PointerType>()->getPointeeType();

  CharUnits ElementSize;
  if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
    return false;

  // As an extension, a type may have zero size (empty struct or union in
  // C, array of zero length). Pointer subtraction in such cases has
  // undefined behavior, so is not constant.
  if (ElementSize.isZero()) {
    Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
        << ElementType;
    return false;
  }

  // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
  // and produce incorrect results when it overflows. Such behavior
  // appears to be non-conforming, but is common, so perhaps we should
  // assume the standard intended for such cases to be undefined behavior
  // and check for them.

  // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
  // overflow in the final conversion to ptrdiff_t.
  APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
  APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
  APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true),
                  false);
  APSInt TrueResult = (LHS - RHS) / ElemSize;
  APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));

  if (Result.extend(65) != TrueResult &&
      !HandleOverflow(Info, E, TrueResult, E->getType()))
    return false;
  return Success(Result, E);
}

return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13007}

13009/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
13010/// a result as the expression's type.
13011bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
                                  const UnaryExprOrTypeTraitExpr *E) {
switch(E->getKind()) {
case UETT_PreferredAlignOf:
case UETT_AlignOf: {
  if (E->isArgumentType())
    return Success(GetAlignOfType(Info, E->getArgumentType(), E->getKind()),
                   E);
  else
    return Success(GetAlignOfExpr(Info, E->getArgumentExpr(), E->getKind()),
                   E);
}

case UETT_VecStep: {
  QualType Ty = E->getTypeOfArgument();

  if (Ty->isVectorType()) {
    unsigned n = Ty->castAs<VectorType>()->getNumElements();

    // The vec_step built-in functions that take a 3-component
    // vector return 4. (OpenCL 1.1 spec 6.11.12)
    if (n == 3)
      n = 4;

    return Success(n, E);
  } else
    return Success(1, E);
}

case UETT_SizeOf: {
  QualType SrcTy = E->getTypeOfArgument();
  // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
  //   the result is the size of the referenced type."
  if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
    SrcTy = Ref->getPointeeType();

  CharUnits Sizeof;
  if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
    return false;
  return Success(Sizeof, E);
}
case UETT_OpenMPRequiredSimdAlign:
  assert(E->isArgumentType())((void)0);
  return Success(
      Info.Ctx.toCharUnitsFromBits(
                  Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType()))
          .getQuantity(),
      E);
}

llvm_unreachable("unknown expr/type trait")__builtin_unreachable();
13062}

13064bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
CharUnits Result;
unsigned n = OOE->getNumComponents();
if (n == 0)
  return Error(OOE);
QualType CurrentType = OOE->getTypeSourceInfo()->getType();
for (unsigned i = 0; i != n; ++i) {
  OffsetOfNode ON = OOE->getComponent(i);
  switch (ON.getKind()) {
  case OffsetOfNode::Array: {
    const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
    APSInt IdxResult;
    if (!EvaluateInteger(Idx, IdxResult, Info))
      return false;
    const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
    if (!AT)
      return Error(OOE);
    CurrentType = AT->getElementType();
    CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
    Result += IdxResult.getSExtValue() * ElementSize;
    break;
  }

  case OffsetOfNode::Field: {
    FieldDecl *MemberDecl = ON.getField();
    const RecordType *RT = CurrentType->getAs<RecordType>();
    if (!RT)
      return Error(OOE);
    RecordDecl *RD = RT->getDecl();
    if (RD->isInvalidDecl()) return false;
    const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
    unsigned i = MemberDecl->getFieldIndex();
    assert(i < RL.getFieldCount() && "offsetof field in wrong type")((void)0);
    Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
    CurrentType = MemberDecl->getType().getNonReferenceType();
    break;
  }

  case OffsetOfNode::Identifier:
    llvm_unreachable("dependent __builtin_offsetof")__builtin_unreachable();

  case OffsetOfNode::Base: {
    CXXBaseSpecifier *BaseSpec = ON.getBase();
    if (BaseSpec->isVirtual())
      return Error(OOE);

    // Find the layout of the class whose base we are looking into.
    const RecordType *RT = CurrentType->getAs<RecordType>();
    if (!RT)
      return Error(OOE);
    RecordDecl *RD = RT->getDecl();
    if (RD->isInvalidDecl()) return false;
    const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);

    // Find the base class itself.
    CurrentType = BaseSpec->getType();
    const RecordType *BaseRT = CurrentType->getAs<RecordType>();
    if (!BaseRT)
      return Error(OOE);

    // Add the offset to the base.
    Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
    break;
  }
  }
}
return Success(Result, OOE);
13131}

13133bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
switch (E->getOpcode()) {
default:
  // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
  // See C99 6.6p3.
  return Error(E);
case UO_Extension:
  // FIXME: Should extension allow i-c-e extension expressions in its scope?
  // If so, we could clear the diagnostic ID.
  return Visit(E->getSubExpr());
case UO_Plus:
  // The result is just the value.
  return Visit(E->getSubExpr());
case UO_Minus: {
  if (!Visit(E->getSubExpr()))
    return false;
  if (!Result.isInt()) return Error(E);
  const APSInt &Value = Result.getInt();
  if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() &&
      !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
                      E->getType()))
    return false;
  return Success(-Value, E);
}
case UO_Not: {
  if (!Visit(E->getSubExpr()))
    return false;
  if (!Result.isInt()) return Error(E);
  return Success(~Result.getInt(), E);
}
case UO_LNot: {
  bool bres;
  if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
    return false;
  return Success(!bres, E);
}
}
13170}

13172/// HandleCast - This is used to evaluate implicit or explicit casts where the
13173/// result type is integer.
13174bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
const Expr *SubExpr = E->getSubExpr();
QualType DestType = E->getType();
QualType SrcType = SubExpr->getType();

switch (E->getCastKind()) {
case CK_BaseToDerived:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_Dynamic:
case CK_ToUnion:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_NullToPointer:
case CK_NullToMemberPointer:
case CK_BaseToDerivedMemberPointer:
case CK_DerivedToBaseMemberPointer:
case CK_ReinterpretMemberPointer:
case CK_ConstructorConversion:
case CK_IntegralToPointer:
case CK_ToVoid:
case CK_VectorSplat:
case CK_IntegralToFloating:
case CK_FloatingCast:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
case CK_ObjCObjectLValueCast:
case CK_FloatingRealToComplex:
case CK_FloatingComplexToReal:
case CK_FloatingComplexCast:
case CK_FloatingComplexToIntegralComplex:
case CK_IntegralRealToComplex:
case CK_IntegralComplexCast:
case CK_IntegralComplexToFloatingComplex:
case CK_BuiltinFnToFnPtr:
case CK_ZeroToOCLOpaqueType:
case CK_NonAtomicToAtomic:
case CK_AddressSpaceConversion:
case CK_IntToOCLSampler:
case CK_FloatingToFixedPoint:
case CK_FixedPointToFloating:
case CK_FixedPointCast:
case CK_IntegralToFixedPoint:
case CK_MatrixCast:
  llvm_unreachable("invalid cast kind for integral value")__builtin_unreachable();

case CK_BitCast:
case CK_Dependent:
case CK_LValueBitCast:
case CK_ARCProduceObject:
case CK_ARCConsumeObject:
case CK_ARCReclaimReturnedObject:
case CK_ARCExtendBlockObject:
case CK_CopyAndAutoreleaseBlockObject:
  return Error(E);

case CK_UserDefinedConversion:
case CK_LValueToRValue:
case CK_AtomicToNonAtomic:
case CK_NoOp:
case CK_LValueToRValueBitCast:
  return ExprEvaluatorBaseTy::VisitCastExpr(E);

case CK_MemberPointerToBoolean:
case CK_PointerToBoolean:
case CK_IntegralToBoolean:
case CK_FloatingToBoolean:
case CK_BooleanToSignedIntegral:
case CK_FloatingComplexToBoolean:
case CK_IntegralComplexToBoolean: {
  bool BoolResult;
  if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
    return false;
  uint64_t IntResult = BoolResult;
  if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
    IntResult = (uint64_t)-1;
  return Success(IntResult, E);
}

case CK_FixedPointToIntegral: {
  APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SrcType));
  if (!EvaluateFixedPoint(SubExpr, Src, Info))
    return false;
  bool Overflowed;
  llvm::APSInt Result = Src.convertToInt(
      Info.Ctx.getIntWidth(DestType),
      DestType->isSignedIntegerOrEnumerationType(), &Overflowed);
  if (Overflowed && !HandleOverflow(Info, E, Result, DestType))
    return false;
  return Success(Result, E);
}

case CK_FixedPointToBoolean: {
  // Unsigned padding does not affect this.
  APValue Val;
  if (!Evaluate(Val, Info, SubExpr))
    return false;
  return Success(Val.getFixedPoint().getBoolValue(), E);
}

case CK_IntegralCast: {
  if (!Visit(SubExpr))
    return false;

  if (!Result.isInt()) {
    // Allow casts of address-of-label differences if they are no-ops
    // or narrowing.  (The narrowing case isn't actually guaranteed to
    // be constant-evaluatable except in some narrow cases which are hard
    // to detect here.  We let it through on the assumption the user knows
    // what they are doing.)
    if (Result.isAddrLabelDiff())
      return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
    // Only allow casts of lvalues if they are lossless.
    return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
  }

  return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
                                    Result.getInt()), E);
}

case CK_PointerToIntegral: {
  CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;

  LValue LV;
  if (!EvaluatePointer(SubExpr, LV, Info))
    return false;

  if (LV.getLValueBase()) {
    // Only allow based lvalue casts if they are lossless.
    // FIXME: Allow a larger integer size than the pointer size, and allow
    // narrowing back down to pointer width in subsequent integral casts.
    // FIXME: Check integer type's active bits, not its type size.
    if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
      return Error(E);

    LV.Designator.setInvalid();
    LV.moveInto(Result);
    return true;
  }

  APSInt AsInt;
  APValue V;
  LV.moveInto(V);
  if (!V.toIntegralConstant(AsInt, SrcType, Info.Ctx))
    llvm_unreachable("Can't cast this!")__builtin_unreachable();

  return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
}

case CK_IntegralComplexToReal: {
  ComplexValue C;
  if (!EvaluateComplex(SubExpr, C, Info))
    return false;
  return Success(C.getComplexIntReal(), E);
}

case CK_FloatingToIntegral: {
  APFloat F(0.0);
  if (!EvaluateFloat(SubExpr, F, Info))
    return false;

  APSInt Value;
  if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
    return false;
  return Success(Value, E);
}
}

llvm_unreachable("unknown cast resulting in integral value")__builtin_unreachable();
13344}

13346bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isAnyComplexType()) {
  ComplexValue LV;
  if (!EvaluateComplex(E->getSubExpr(), LV, Info))
    return false;
  if (!LV.isComplexInt())
    return Error(E);
  return Success(LV.getComplexIntReal(), E);
}

return Visit(E->getSubExpr());
13357}

13359bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isComplexIntegerType()) {
  ComplexValue LV;
  if (!EvaluateComplex(E->getSubExpr(), LV, Info))
    return false;
  if (!LV.isComplexInt())
    return Error(E);
  return Success(LV.getComplexIntImag(), E);
}

VisitIgnoredValue(E->getSubExpr());
return Success(0, E);
13371}

13373bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
return Success(E->getPackLength(), E);
13375}

13377bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
return Success(E->getValue(), E);
13379}

13381bool IntExprEvaluator::VisitConceptSpecializationExpr(
     const ConceptSpecializationExpr *E) {
return Success(E->isSatisfied(), E);
13384}

13386bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) {
return Success(E->isSatisfied(), E);
13388}

13390bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
switch (E->getOpcode()) {
  default:
    // Invalid unary operators
    return Error(E);
  case UO_Plus:
    // The result is just the value.
    return Visit(E->getSubExpr());
  case UO_Minus: {
    if (!Visit(E->getSubExpr())) return false;
    if (!Result.isFixedPoint())
      return Error(E);
    bool Overflowed;
    APFixedPoint Negated = Result.getFixedPoint().negate(&Overflowed);
    if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType()))
      return false;
    return Success(Negated, E);
  }
  case UO_LNot: {
    bool bres;
    if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
      return false;
    return Success(!bres, E);
  }
}
13415}

13417bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) {
const Expr *SubExpr = E->getSubExpr();
QualType DestType = E->getType();
assert(DestType->isFixedPointType() &&((void)0)
       "Expected destination type to be a fixed point type")((void)0);
auto DestFXSema = Info.Ctx.getFixedPointSemantics(DestType);

switch (E->getCastKind()) {
case CK_FixedPointCast: {
  APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
  if (!EvaluateFixedPoint(SubExpr, Src, Info))
    return false;
  bool Overflowed;
  APFixedPoint Result = Src.convert(DestFXSema, &Overflowed);
  if (Overflowed) {
    if (Info.checkingForUndefinedBehavior())
      Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
                                       diag::warn_fixedpoint_constant_overflow)
        << Result.toString() << E->getType();
    if (!HandleOverflow(Info, E, Result, E->getType()))
      return false;
  }
  return Success(Result, E);
}
case CK_IntegralToFixedPoint: {
  APSInt Src;
  if (!EvaluateInteger(SubExpr, Src, Info))
    return false;

  bool Overflowed;
  APFixedPoint IntResult = APFixedPoint::getFromIntValue(
      Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed);

  if (Overflowed) {
    if (Info.checkingForUndefinedBehavior())
      Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
                                       diag::warn_fixedpoint_constant_overflow)
        << IntResult.toString() << E->getType();
    if (!HandleOverflow(Info, E, IntResult, E->getType()))
      return false;
  }

  return Success(IntResult, E);
}
case CK_FloatingToFixedPoint: {
  APFloat Src(0.0);
  if (!EvaluateFloat(SubExpr, Src, Info))
    return false;

  bool Overflowed;
  APFixedPoint Result = APFixedPoint::getFromFloatValue(
      Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed);

  if (Overflowed) {
    if (Info.checkingForUndefinedBehavior())
      Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
                                       diag::warn_fixedpoint_constant_overflow)
        << Result.toString() << E->getType();
    if (!HandleOverflow(Info, E, Result, E->getType()))
      return false;
  }

  return Success(Result, E);
}
case CK_NoOp:
case CK_LValueToRValue:
  return ExprEvaluatorBaseTy::VisitCastExpr(E);
default:
  return Error(E);
}
13487}

13489bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
  return ExprEvaluatorBaseTy::VisitBinaryOperator(E);

const Expr *LHS = E->getLHS();
const Expr *RHS = E->getRHS();
FixedPointSemantics ResultFXSema =
    Info.Ctx.getFixedPointSemantics(E->getType());

APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHS->getType()));
if (!EvaluateFixedPointOrInteger(LHS, LHSFX, Info))
  return false;
APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHS->getType()));
if (!EvaluateFixedPointOrInteger(RHS, RHSFX, Info))
  return false;

bool OpOverflow = false, ConversionOverflow = false;
APFixedPoint Result(LHSFX.getSemantics());
switch (E->getOpcode()) {
case BO_Add: {
  Result = LHSFX.add(RHSFX, &OpOverflow)
                .convert(ResultFXSema, &ConversionOverflow);
  break;
}
case BO_Sub: {
  Result = LHSFX.sub(RHSFX, &OpOverflow)
                .convert(ResultFXSema, &ConversionOverflow);
  break;
}
case BO_Mul: {
  Result = LHSFX.mul(RHSFX, &OpOverflow)
                .convert(ResultFXSema, &ConversionOverflow);
  break;
}
case BO_Div: {
  if (RHSFX.getValue() == 0) {
    Info.FFDiag(E, diag::note_expr_divide_by_zero);
    return false;
  }
  Result = LHSFX.div(RHSFX, &OpOverflow)
                .convert(ResultFXSema, &ConversionOverflow);
  break;
}
case BO_Shl:
case BO_Shr: {
  FixedPointSemantics LHSSema = LHSFX.getSemantics();
  llvm::APSInt RHSVal = RHSFX.getValue();

  unsigned ShiftBW =
      LHSSema.getWidth() - (unsigned)LHSSema.hasUnsignedPadding();
  unsigned Amt = RHSVal.getLimitedValue(ShiftBW - 1);
  // Embedded-C 4.1.6.2.2:
  //   The right operand must be nonnegative and less than the total number
  //   of (nonpadding) bits of the fixed-point operand ...
  if (RHSVal.isNegative())
    Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHSVal;
  else if (Amt != RHSVal)
    Info.CCEDiag(E, diag::note_constexpr_large_shift)
        << RHSVal << E->getType() << ShiftBW;

  if (E->getOpcode() == BO_Shl)
    Result = LHSFX.shl(Amt, &OpOverflow);
  else
    Result = LHSFX.shr(Amt, &OpOverflow);
  break;
}
default:
  return false;
}
if (OpOverflow || ConversionOverflow) {
  if (Info.checkingForUndefinedBehavior())
    Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
                                     diag::warn_fixedpoint_constant_overflow)
      << Result.toString() << E->getType();
  if (!HandleOverflow(Info, E, Result, E->getType()))
    return false;
}
return Success(Result, E);
13567}

13569//===----------------------------------------------------------------------===//
13570// Float Evaluation
13571//===----------------------------------------------------------------------===//

13573namespace {
13574class FloatExprEvaluator
: public ExprEvaluatorBase<FloatExprEvaluator> {
APFloat &Result;
13577public:
FloatExprEvaluator(EvalInfo &info, APFloat &result)
  : ExprEvaluatorBaseTy(info), Result(result) {}

bool Success(const APValue &V, const Expr *e) {
  Result = V.getFloat();
  return true;
}

bool ZeroInitialization(const Expr *E) {
  Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
  return true;
}

bool VisitCallExpr(const CallExpr *E);

bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitFloatingLiteral(const FloatingLiteral *E);
bool VisitCastExpr(const CastExpr *E);

bool VisitUnaryReal(const UnaryOperator *E);
bool VisitUnaryImag(const UnaryOperator *E);

// FIXME: Missing: array subscript of vector, member of vector
13602};
13603} // end anonymous namespace

13605static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isRealFloatingType())((void)0);
return FloatExprEvaluator(Info, Result).Visit(E);
13609}

13611static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
                                QualType ResultTy,
                                const Expr *Arg,
                                bool SNaN,
                                llvm::APFloat &Result) {
const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
if (!S) return false;

const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);

llvm::APInt fill;

// Treat empty strings as if they were zero.
if (S->getString().empty())
  fill = llvm::APInt(32, 0);
else if (S->getString().getAsInteger(0, fill))
  return false;

if (Context.getTargetInfo().isNan2008()) {
  if (SNaN)
    Result = llvm::APFloat::getSNaN(Sem, false, &fill);
  else
    Result = llvm::APFloat::getQNaN(Sem, false, &fill);
} else {
  // Prior to IEEE 754-2008, architectures were allowed to choose whether
  // the first bit of their significand was set for qNaN or sNaN. MIPS chose
  // a different encoding to what became a standard in 2008, and for pre-
  // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
  // sNaN. This is now known as "legacy NaN" encoding.
  if (SNaN)
    Result = llvm::APFloat::getQNaN(Sem, false, &fill);
  else
    Result = llvm::APFloat::getSNaN(Sem, false, &fill);
}

return true;
13647}

13649bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
switch (E->getBuiltinCallee()) {
default:
  return ExprEvaluatorBaseTy::VisitCallExpr(E);

case Builtin::BI__builtin_huge_val:
case Builtin::BI__builtin_huge_valf:
case Builtin::BI__builtin_huge_vall:
case Builtin::BI__builtin_huge_valf128:
case Builtin::BI__builtin_inf:
case Builtin::BI__builtin_inff:
case Builtin::BI__builtin_infl:
case Builtin::BI__builtin_inff128: {
  const llvm::fltSemantics &Sem =
    Info.Ctx.getFloatTypeSemantics(E->getType());
  Result = llvm::APFloat::getInf(Sem);
  return true;
}

case Builtin::BI__builtin_nans:
case Builtin::BI__builtin_nansf:
case Builtin::BI__builtin_nansl:
case Builtin::BI__builtin_nansf128:
  if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
                             true, Result))
    return Error(E);
  return true;

case Builtin::BI__builtin_nan:
case Builtin::BI__builtin_nanf:
case Builtin::BI__builtin_nanl:
case Builtin::BI__builtin_nanf128:
  // If this is __builtin_nan() turn this into a nan, otherwise we
  // can't constant fold it.
  if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
                             false, Result))
    return Error(E);
  return true;

case Builtin::BI__builtin_fabs:
case Builtin::BI__builtin_fabsf:
case Builtin::BI__builtin_fabsl:
case Builtin::BI__builtin_fabsf128:
  // The C standard says "fabs raises no floating-point exceptions,
  // even if x is a signaling NaN. The returned value is independent of
  // the current rounding direction mode."  Therefore constant folding can
  // proceed without regard to the floating point settings.
  // Reference, WG14 N2478 F.10.4.3
  if (!EvaluateFloat(E->getArg(0), Result, Info))
    return false;

  if (Result.isNegative())
    Result.changeSign();
  return true;

case Builtin::BI__arithmetic_fence:
  return EvaluateFloat(E->getArg(0), Result, Info);

// FIXME: Builtin::BI__builtin_powi
// FIXME: Builtin::BI__builtin_powif
// FIXME: Builtin::BI__builtin_powil

case Builtin::BI__builtin_copysign:
case Builtin::BI__builtin_copysignf:
case Builtin::BI__builtin_copysignl:
case Builtin::BI__builtin_copysignf128: {
  APFloat RHS(0.);
  if (!EvaluateFloat(E->getArg(0), Result, Info) ||
      !EvaluateFloat(E->getArg(1), RHS, Info))
    return false;
  Result.copySign(RHS);
  return true;
}
}
13723}

13725bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isAnyComplexType()) {
  ComplexValue CV;
  if (!EvaluateComplex(E->getSubExpr(), CV, Info))
    return false;
  Result = CV.FloatReal;
  return true;
}

return Visit(E->getSubExpr());
13735}

13737bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
if (E->getSubExpr()->getType()->isAnyComplexType()) {
  ComplexValue CV;
  if (!EvaluateComplex(E->getSubExpr(), CV, Info))
    return false;
  Result = CV.FloatImag;
  return true;
}

VisitIgnoredValue(E->getSubExpr());
const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
Result = llvm::APFloat::getZero(Sem);
return true;
13750}

13752bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
switch (E->getOpcode()) {
default: return Error(E);
case UO_Plus:
  return EvaluateFloat(E->getSubExpr(), Result, Info);
case UO_Minus:
  // In C standard, WG14 N2478 F.3 p4
  // "the unary - raises no floating point exceptions,
  // even if the operand is signalling."
  if (!EvaluateFloat(E->getSubExpr(), Result, Info))
    return false;
  Result.changeSign();
  return true;
}
13766}

13768bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
  return ExprEvaluatorBaseTy::VisitBinaryOperator(E);

APFloat RHS(0.0);
bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
if (!LHSOK && !Info.noteFailure())
  return false;
return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK &&
       handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS);
13778}

13780bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
Result = E->getValue();
return true;
13783}

13785bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
const Expr* SubExpr = E->getSubExpr();

switch (E->getCastKind()) {
default:
  return ExprEvaluatorBaseTy::VisitCastExpr(E);

case CK_IntegralToFloating: {
  APSInt IntResult;
  const FPOptions FPO = E->getFPFeaturesInEffect(
                                Info.Ctx.getLangOpts());
  return EvaluateInteger(SubExpr, IntResult, Info) &&
         HandleIntToFloatCast(Info, E, FPO, SubExpr->getType(),
                              IntResult, E->getType(), Result);
}

case CK_FixedPointToFloating: {
  APFixedPoint FixResult(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
  if (!EvaluateFixedPoint(SubExpr, FixResult, Info))
    return false;
  Result =
      FixResult.convertToFloat(Info.Ctx.getFloatTypeSemantics(E->getType()));
  return true;
}

case CK_FloatingCast: {
  if (!Visit(SubExpr))
    return false;
  return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
                                Result);
}

case CK_FloatingComplexToReal: {
  ComplexValue V;
  if (!EvaluateComplex(SubExpr, V, Info))
    return false;
  Result = V.getComplexFloatReal();
  return true;
}
}
13825}

13827//===----------------------------------------------------------------------===//
13828// Complex Evaluation (for float and integer)
13829//===----------------------------------------------------------------------===//

13831namespace {
13832class ComplexExprEvaluator
: public ExprEvaluatorBase<ComplexExprEvaluator> {
ComplexValue &Result;

13836public:
ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
  : ExprEvaluatorBaseTy(info), Result(Result) {}

bool Success(const APValue &V, const Expr *e) {
  Result.setFrom(V);
  return true;
}

bool ZeroInitialization(const Expr *E);

//===--------------------------------------------------------------------===//
//                            Visitor Methods
//===--------------------------------------------------------------------===//

bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
bool VisitCastExpr(const CastExpr *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitInitListExpr(const InitListExpr *E);
bool VisitCallExpr(const CallExpr *E);
13857};
13858} // end anonymous namespace

13860static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
                          EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isAnyComplexType())((void)0);
return ComplexExprEvaluator(Info, Result).Visit(E);
13865}

13867bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
if (ElemTy->isRealFloatingType()) {
  Result.makeComplexFloat();
  APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
  Result.FloatReal = Zero;
  Result.FloatImag = Zero;
} else {
  Result.makeComplexInt();
  APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
  Result.IntReal = Zero;
  Result.IntImag = Zero;
}
return true;
13881}

13883bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
const Expr* SubExpr = E->getSubExpr();

if (SubExpr->getType()->isRealFloatingType()) {
  Result.makeComplexFloat();
  APFloat &Imag = Result.FloatImag;
  if (!EvaluateFloat(SubExpr, Imag, Info))
    return false;

  Result.FloatReal = APFloat(Imag.getSemantics());
  return true;
} else {
  assert(SubExpr->getType()->isIntegerType() &&((void)0)
         "Unexpected imaginary literal.")((void)0);

  Result.makeComplexInt();
  APSInt &Imag = Result.IntImag;
  if (!EvaluateInteger(SubExpr, Imag, Info))
    return false;

  Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
  return true;
}
13906}

13908bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {

switch (E->getCastKind()) {
case CK_BitCast:
case CK_BaseToDerived:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_Dynamic:
case CK_ToUnion:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_NullToPointer:
case CK_NullToMemberPointer:
case CK_BaseToDerivedMemberPointer:
case CK_DerivedToBaseMemberPointer:
case CK_MemberPointerToBoolean:
case CK_ReinterpretMemberPointer:
case CK_ConstructorConversion:
case CK_IntegralToPointer:
case CK_PointerToIntegral:
case CK_PointerToBoolean:
case CK_ToVoid:
case CK_VectorSplat:
case CK_IntegralCast:
case CK_BooleanToSignedIntegral:
case CK_IntegralToBoolean:
case CK_IntegralToFloating:
case CK_FloatingToIntegral:
case CK_FloatingToBoolean:
case CK_FloatingCast:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
case CK_ObjCObjectLValueCast:
case CK_FloatingComplexToReal:
case CK_FloatingComplexToBoolean:
case CK_IntegralComplexToReal:
case CK_IntegralComplexToBoolean:
case CK_ARCProduceObject:
case CK_ARCConsumeObject:
case CK_ARCReclaimReturnedObject:
case CK_ARCExtendBlockObject:
case CK_CopyAndAutoreleaseBlockObject:
case CK_BuiltinFnToFnPtr:
case CK_ZeroToOCLOpaqueType:
case CK_NonAtomicToAtomic:
case CK_AddressSpaceConversion:
case CK_IntToOCLSampler:
case CK_FloatingToFixedPoint:
case CK_FixedPointToFloating:
case CK_FixedPointCast:
case CK_FixedPointToBoolean:
case CK_FixedPointToIntegral:
case CK_IntegralToFixedPoint:
case CK_MatrixCast:
  llvm_unreachable("invalid cast kind for complex value")__builtin_unreachable();

case CK_LValueToRValue:
case CK_AtomicToNonAtomic:
case CK_NoOp:
case CK_LValueToRValueBitCast:
  return ExprEvaluatorBaseTy::VisitCastExpr(E);

case CK_Dependent:
case CK_LValueBitCast:
case CK_UserDefinedConversion:
  return Error(E);

case CK_FloatingRealToComplex: {
  APFloat &Real = Result.FloatReal;
  if (!EvaluateFloat(E->getSubExpr(), Real, Info))
    return false;

  Result.makeComplexFloat();
  Result.FloatImag = APFloat(Real.getSemantics());
  return true;
}

case CK_FloatingComplexCast: {
  if (!Visit(E->getSubExpr()))
    return false;

  QualType To = E->getType()->castAs<ComplexType>()->getElementType();
  QualType From
    = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();

  return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
         HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
}

case CK_FloatingComplexToIntegralComplex: {
  if (!Visit(E->getSubExpr()))
    return false;

  QualType To = E->getType()->castAs<ComplexType>()->getElementType();
  QualType From
    = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
  Result.makeComplexInt();
  return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
                              To, Result.IntReal) &&
         HandleFloatToIntCast(Info, E, From, Result.FloatImag,
                              To, Result.IntImag);
}

case CK_IntegralRealToComplex: {
  APSInt &Real = Result.IntReal;
  if (!EvaluateInteger(E->getSubExpr(), Real, Info))
    return false;

  Result.makeComplexInt();
  Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
  return true;
}

case CK_IntegralComplexCast: {
  if (!Visit(E->getSubExpr()))
    return false;

  QualType To = E->getType()->castAs<ComplexType>()->getElementType();
  QualType From
    = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();

  Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
  Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
  return true;
}

case CK_IntegralComplexToFloatingComplex: {
  if (!Visit(E->getSubExpr()))
    return false;

  const FPOptions FPO = E->getFPFeaturesInEffect(
                                Info.Ctx.getLangOpts());
  QualType To = E->getType()->castAs<ComplexType>()->getElementType();
  QualType From
    = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
  Result.makeComplexFloat();
  return HandleIntToFloatCast(Info, E, FPO, From, Result.IntReal,
                              To, Result.FloatReal) &&
         HandleIntToFloatCast(Info, E, FPO, From, Result.IntImag,
                              To, Result.FloatImag);
}
}

llvm_unreachable("unknown cast resulting in complex value")__builtin_unreachable();
14053}

14055bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
  return ExprEvaluatorBaseTy::VisitBinaryOperator(E);

// Track whether the LHS or RHS is real at the type system level. When this is
// the case we can simplify our evaluation strategy.
bool LHSReal = false, RHSReal = false;

bool LHSOK;
if (E->getLHS()->getType()->isRealFloatingType()) {
  LHSReal = true;
  APFloat &Real = Result.FloatReal;
  LHSOK = EvaluateFloat(E->getLHS(), Real, Info);
  if (LHSOK) {
    Result.makeComplexFloat();
    Result.FloatImag = APFloat(Real.getSemantics());
  }
} else {
  LHSOK = Visit(E->getLHS());
}
if (!LHSOK && !Info.noteFailure())
  return false;

ComplexValue RHS;
if (E->getRHS()->getType()->isRealFloatingType()) {
  RHSReal = true;
  APFloat &Real = RHS.FloatReal;
  if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK)
    return false;
  RHS.makeComplexFloat();
  RHS.FloatImag = APFloat(Real.getSemantics());
} else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
  return false;

assert(!(LHSReal && RHSReal) &&((void)0)
       "Cannot have both operands of a complex operation be real.")((void)0);
switch (E->getOpcode()) {
default: return Error(E);
case BO_Add:
  if (Result.isComplexFloat()) {
    Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
                                     APFloat::rmNearestTiesToEven);
    if (LHSReal)
      Result.getComplexFloatImag() = RHS.getComplexFloatImag();
    else if (!RHSReal)
      Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
                                       APFloat::rmNearestTiesToEven);
  } else {
    Result.getComplexIntReal() += RHS.getComplexIntReal();
    Result.getComplexIntImag() += RHS.getComplexIntImag();
  }
  break;
case BO_Sub:
  if (Result.isComplexFloat()) {
    Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
                                          APFloat::rmNearestTiesToEven);
    if (LHSReal) {
      Result.getComplexFloatImag() = RHS.getComplexFloatImag();
      Result.getComplexFloatImag().changeSign();
    } else if (!RHSReal) {
      Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
                                            APFloat::rmNearestTiesToEven);
    }
  } else {
    Result.getComplexIntReal() -= RHS.getComplexIntReal();
    Result.getComplexIntImag() -= RHS.getComplexIntImag();
  }
  break;
case BO_Mul:
  if (Result.isComplexFloat()) {
    // This is an implementation of complex multiplication according to the
    // constraints laid out in C11 Annex G. The implementation uses the
    // following naming scheme:
    //   (a + ib) * (c + id)
    ComplexValue LHS = Result;
    APFloat &A = LHS.getComplexFloatReal();
    APFloat &B = LHS.getComplexFloatImag();
    APFloat &C = RHS.getComplexFloatReal();
    APFloat &D = RHS.getComplexFloatImag();
    APFloat &ResR = Result.getComplexFloatReal();
    APFloat &ResI = Result.getComplexFloatImag();
    if (LHSReal) {
      assert(!RHSReal && "Cannot have two real operands for a complex op!")((void)0);
      ResR = A * C;
      ResI = A * D;
    } else if (RHSReal) {
      ResR = C * A;
      ResI = C * B;
    } else {
      // In the fully general case, we need to handle NaNs and infinities
      // robustly.
      APFloat AC = A * C;
      APFloat BD = B * D;
      APFloat AD = A * D;
      APFloat BC = B * C;
      ResR = AC - BD;
      ResI = AD + BC;
      if (ResR.isNaN() && ResI.isNaN()) {
        bool Recalc = false;
        if (A.isInfinity() || B.isInfinity()) {
          A = APFloat::copySign(
              APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
          B = APFloat::copySign(
              APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
          if (C.isNaN())
            C = APFloat::copySign(APFloat(C.getSemantics()), C);
          if (D.isNaN())
            D = APFloat::copySign(APFloat(D.getSemantics()), D);
          Recalc = true;
        }
        if (C.isInfinity() || D.isInfinity()) {
          C = APFloat::copySign(
              APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
          D = APFloat::copySign(
              APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
          if (A.isNaN())
            A = APFloat::copySign(APFloat(A.getSemantics()), A);
          if (B.isNaN())
            B = APFloat::copySign(APFloat(B.getSemantics()), B);
          Recalc = true;
        }
        if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
                        AD.isInfinity() || BC.isInfinity())) {
          if (A.isNaN())
            A = APFloat::copySign(APFloat(A.getSemantics()), A);
          if (B.isNaN())
            B = APFloat::copySign(APFloat(B.getSemantics()), B);
          if (C.isNaN())
            C = APFloat::copySign(APFloat(C.getSemantics()), C);
          if (D.isNaN())
            D = APFloat::copySign(APFloat(D.getSemantics()), D);
          Recalc = true;
        }
        if (Recalc) {
          ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
          ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
        }
      }
    }
  } else {
    ComplexValue LHS = Result;
    Result.getComplexIntReal() =
      (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
       LHS.getComplexIntImag() * RHS.getComplexIntImag());
    Result.getComplexIntImag() =
      (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
       LHS.getComplexIntImag() * RHS.getComplexIntReal());
  }
  break;
case BO_Div:
  if (Result.isComplexFloat()) {
    // This is an implementation of complex division according to the
    // constraints laid out in C11 Annex G. The implementation uses the
    // following naming scheme:
    //   (a + ib) / (c + id)
    ComplexValue LHS = Result;
    APFloat &A = LHS.getComplexFloatReal();
    APFloat &B = LHS.getComplexFloatImag();
    APFloat &C = RHS.getComplexFloatReal();
    APFloat &D = RHS.getComplexFloatImag();
    APFloat &ResR = Result.getComplexFloatReal();
    APFloat &ResI = Result.getComplexFloatImag();
    if (RHSReal) {
      ResR = A / C;
      ResI = B / C;
    } else {
      if (LHSReal) {
        // No real optimizations we can do here, stub out with zero.
        B = APFloat::getZero(A.getSemantics());
      }
      int DenomLogB = 0;
      APFloat MaxCD = maxnum(abs(C), abs(D));
      if (MaxCD.isFinite()) {
        DenomLogB = ilogb(MaxCD);
        C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven);
        D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven);
      }
      APFloat Denom = C * C + D * D;
      ResR = scalbn((A * C + B * D) / Denom, -DenomLogB,
                    APFloat::rmNearestTiesToEven);
      ResI = scalbn((B * C - A * D) / Denom, -DenomLogB,
                    APFloat::rmNearestTiesToEven);
      if (ResR.isNaN() && ResI.isNaN()) {
        if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
          ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A;
          ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B;
        } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
                   D.isFinite()) {
          A = APFloat::copySign(
              APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
          B = APFloat::copySign(
              APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
          ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D);
          ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D);
        } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
          C = APFloat::copySign(
              APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
          D = APFloat::copySign(
              APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
          ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D);
          ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D);
        }
      }
    }
  } else {
    if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
      return Error(E, diag::note_expr_divide_by_zero);

    ComplexValue LHS = Result;
    APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
      RHS.getComplexIntImag() * RHS.getComplexIntImag();
    Result.getComplexIntReal() =
      (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
       LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
    Result.getComplexIntImag() =
      (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
       LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
  }
  break;
}

return true;
14277}

14279bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
// Get the operand value into 'Result'.
if (!Visit(E->getSubExpr()))
  return false;

switch (E->getOpcode()) {
default:
  return Error(E);
case UO_Extension:
  return true;
case UO_Plus:
  // The result is always just the subexpr.
  return true;
case UO_Minus:
  if (Result.isComplexFloat()) {
    Result.getComplexFloatReal().changeSign();
    Result.getComplexFloatImag().changeSign();
  }
  else {
    Result.getComplexIntReal() = -Result.getComplexIntReal();
    Result.getComplexIntImag() = -Result.getComplexIntImag();
  }
  return true;
case UO_Not:
  if (Result.isComplexFloat())
    Result.getComplexFloatImag().changeSign();
  else
    Result.getComplexIntImag() = -Result.getComplexIntImag();
  return true;
}
14309}

14311bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
if (E->getNumInits() == 2) {
  if (E->getType()->isComplexType()) {
    Result.makeComplexFloat();
    if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
      return false;
    if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
      return false;
  } else {
    Result.makeComplexInt();
    if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
      return false;
    if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
      return false;
  }
  return true;
}
return ExprEvaluatorBaseTy::VisitInitListExpr(E);
14329}

14331bool ComplexExprEvaluator::VisitCallExpr(const CallExpr *E) {
switch (E->getBuiltinCallee()) {
case Builtin::BI__builtin_complex:
  Result.makeComplexFloat();
  if (!EvaluateFloat(E->getArg(0), Result.FloatReal, Info))
    return false;
  if (!EvaluateFloat(E->getArg(1), Result.FloatImag, Info))
    return false;
  return true;

default:
  break;
}

return ExprEvaluatorBaseTy::VisitCallExpr(E);
14346}

14348//===----------------------------------------------------------------------===//
14349// Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
14350// implicit conversion.
14351//===----------------------------------------------------------------------===//

14353namespace {
14354class AtomicExprEvaluator :
  public ExprEvaluatorBase<AtomicExprEvaluator> {
const LValue *This;
APValue &Result;
14358public:
AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
    : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}

bool Success(const APValue &V, const Expr *E) {
  Result = V;
  return true;
}

bool ZeroInitialization(const Expr *E) {
  ImplicitValueInitExpr VIE(
      E->getType()->castAs<AtomicType>()->getValueType());
  // For atomic-qualified class (and array) types in C++, initialize the
  // _Atomic-wrapped subobject directly, in-place.
  return This ? EvaluateInPlace(Result, Info, *This, &VIE)
              : Evaluate(Result, Info, &VIE);
}

bool VisitCastExpr(const CastExpr *E) {
  switch (E->getCastKind()) {
  default:
    return ExprEvaluatorBaseTy::VisitCastExpr(E);
  case CK_NonAtomicToAtomic:
    return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr())
                : Evaluate(Result, Info, E->getSubExpr());
  }
}
14385};
14386} // end anonymous namespace

14388static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
                         EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isAtomicType())((void)0);
return AtomicExprEvaluator(Info, This, Result).Visit(E);
14393}

14395//===----------------------------------------------------------------------===//
14396// Void expression evaluation, primarily for a cast to void on the LHS of a
14397// comma operator
14398//===----------------------------------------------------------------------===//

14400namespace {
14401class VoidExprEvaluator
: public ExprEvaluatorBase<VoidExprEvaluator> {
14403public:
VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}

bool Success(const APValue &V, const Expr *e) { return true; }

bool ZeroInitialization(const Expr *E) { return true; }

bool VisitCastExpr(const CastExpr *E) {
  switch (E->getCastKind()) {
  default:
    return ExprEvaluatorBaseTy::VisitCastExpr(E);
  case CK_ToVoid:
    VisitIgnoredValue(E->getSubExpr());
    return true;
  }
}

bool VisitCallExpr(const CallExpr *E) {
  switch (E->getBuiltinCallee()) {
  case Builtin::BI__assume:
  case Builtin::BI__builtin_assume:
    // The argument is not evaluated!
    return true;

  case Builtin::BI__builtin_operator_delete:
    return HandleOperatorDeleteCall(Info, E);

  default:
    break;
  }

  return ExprEvaluatorBaseTy::VisitCallExpr(E);
}

bool VisitCXXDeleteExpr(const CXXDeleteExpr *E);
14438};
14439} // end anonymous namespace

14441bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
// We cannot speculatively evaluate a delete expression.
if (Info.SpeculativeEvaluationDepth)
  return false;

FunctionDecl *OperatorDelete = E->getOperatorDelete();
if (!OperatorDelete->isReplaceableGlobalAllocationFunction()) {
  Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
      << isa<CXXMethodDecl>(OperatorDelete) << OperatorDelete;
  return false;
}

const Expr *Arg = E->getArgument();

LValue Pointer;
if (!EvaluatePointer(Arg, Pointer, Info))
  return false;
if (Pointer.Designator.Invalid)
  return false;

// Deleting a null pointer has no effect.
if (Pointer.isNullPointer()) {
  // This is the only case where we need to produce an extension warning:
  // the only other way we can succeed is if we find a dynamic allocation,
  // and we will have warned when we allocated it in that case.
  if (!Info.getLangOpts().CPlusPlus20)
    Info.CCEDiag(E, diag::note_constexpr_new);
  return true;
}

Optional<DynAlloc *> Alloc = CheckDeleteKind(
    Info, E, Pointer, E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New);
if (!Alloc)
  return false;
QualType AllocType = Pointer.Base.getDynamicAllocType();

// For the non-array case, the designator must be empty if the static type
// does not have a virtual destructor.
if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 &&
    !hasVirtualDestructor(Arg->getType()->getPointeeType())) {
  Info.FFDiag(E, diag::note_constexpr_delete_base_nonvirt_dtor)
      << Arg->getType()->getPointeeType() << AllocType;
  return false;
}

// For a class type with a virtual destructor, the selected operator delete
// is the one looked up when building the destructor.
if (!E->isArrayForm() && !E->isGlobalDelete()) {
  const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(AllocType);
  if (VirtualDelete &&
      !VirtualDelete->isReplaceableGlobalAllocationFunction()) {
    Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
        << isa<CXXMethodDecl>(VirtualDelete) << VirtualDelete;
    return false;
  }
}

if (!HandleDestruction(Info, E->getExprLoc(), Pointer.getLValueBase(),
                       (*Alloc)->Value, AllocType))
  return false;

if (!Info.HeapAllocs.erase(Pointer.Base.dyn_cast<DynamicAllocLValue>())) {
  // The element was already erased. This means the destructor call also
  // deleted the object.
  // FIXME: This probably results in undefined behavior before we get this
  // far, and should be diagnosed elsewhere first.
  Info.FFDiag(E, diag::note_constexpr_double_delete);
  return false;
}

return true;
14512}

14514static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
assert(E->isPRValue() && E->getType()->isVoidType())((void)0);
return VoidExprEvaluator(Info).Visit(E);
14518}

14520//===----------------------------------------------------------------------===//
14521// Top level Expr::EvaluateAsRValue method.
14522//===----------------------------------------------------------------------===//

14524static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
assert(!E->isValueDependent())((void)0);
// In C, function designators are not lvalues, but we evaluate them as if they
// are.
QualType T = E->getType();
if (E->isGLValue() || T->isFunctionType()) {
  LValue LV;
  if (!EvaluateLValue(E, LV, Info))
    return false;
  LV.moveInto(Result);
} else if (T->isVectorType()) {
  if (!EvaluateVector(E, Result, Info))
    return false;
} else if (T->isIntegralOrEnumerationType()) {
  if (!IntExprEvaluator(Info, Result).Visit(E))
    return false;
} else if (T->hasPointerRepresentation()) {
  LValue LV;
  if (!EvaluatePointer(E, LV, Info))
    return false;
  LV.moveInto(Result);
} else if (T->isRealFloatingType()) {
  llvm::APFloat F(0.0);
  if (!EvaluateFloat(E, F, Info))
    return false;
  Result = APValue(F);
} else if (T->isAnyComplexType()) {
  ComplexValue C;
  if (!EvaluateComplex(E, C, Info))
    return false;
  C.moveInto(Result);
} else if (T->isFixedPointType()) {
  if (!FixedPointExprEvaluator(Info, Result).Visit(E)) return false;
} else if (T->isMemberPointerType()) {
  MemberPtr P;
  if (!EvaluateMemberPointer(E, P, Info))
    return false;
  P.moveInto(Result);
  return true;
} else if (T->isArrayType()) {
  LValue LV;
  APValue &Value =
      Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV);
  if (!EvaluateArray(E, LV, Value, Info))
    return false;
  Result = Value;
} else if (T->isRecordType()) {
  LValue LV;
  APValue &Value =
      Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV);
  if (!EvaluateRecord(E, LV, Value, Info))
    return false;
  Result = Value;
} else if (T->isVoidType()) {
  if (!Info.getLangOpts().CPlusPlus11)
    Info.CCEDiag(E, diag::note_constexpr_nonliteral)
      << E->getType();
  if (!EvaluateVoid(E, Info))
    return false;
} else if (T->isAtomicType()) {
  QualType Unqual = T.getAtomicUnqualifiedType();
  if (Unqual->isArrayType() || Unqual->isRecordType()) {
    LValue LV;
    APValue &Value = Info.CurrentCall->createTemporary(
        E, Unqual, ScopeKind::FullExpression, LV);
    if (!EvaluateAtomic(E, &LV, Value, Info))
      return false;
  } else {
    if (!EvaluateAtomic(E, nullptr, Result, Info))
      return false;
  }
} else if (Info.getLangOpts().CPlusPlus11) {
  Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
  return false;
} else {
  Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
  return false;
}

return true;
14604}

14606/// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
14607/// cases, the in-place evaluation is essential, since later initializers for
14608/// an object can indirectly refer to subobjects which were initialized earlier.
14609static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
                          const Expr *E, bool AllowNonLiteralTypes) {
assert(!E->isValueDependent())((void)0);

if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
  return false;

if (E->isPRValue()) {
  // Evaluate arrays and record types in-place, so that later initializers can
  // refer to earlier-initialized members of the object.
  QualType T = E->getType();
  if (T->isArrayType())
    return EvaluateArray(E, This, Result, Info);
  else if (T->isRecordType())
    return EvaluateRecord(E, This, Result, Info);
  else if (T->isAtomicType()) {
    QualType Unqual = T.getAtomicUnqualifiedType();
    if (Unqual->isArrayType() || Unqual->isRecordType())
      return EvaluateAtomic(E, &This, Result, Info);
  }
}

// For any other type, in-place evaluation is unimportant.
return Evaluate(Result, Info, E);
14633}

14635/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
14636/// lvalue-to-rvalue cast if it is an lvalue.
14637static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
assert(!E->isValueDependent())((void)0);
if (Info.EnableNewConstInterp) {
  if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, E, Result))
    return false;
} else {
  if (E->getType().isNull())
    return false;

  if (!CheckLiteralType(Info, E))
    return false;

  if (!::Evaluate(Result, Info, E))
    return false;

  if (E->isGLValue()) {
    LValue LV;
    LV.setFrom(Info.Ctx, Result);
    if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
      return false;
  }
}

// Check this core constant expression is a constant expression.
return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
                               ConstantExprKind::Normal) &&
       CheckMemoryLeaks(Info);
14664}

14666static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
                               const ASTContext &Ctx, bool &IsConst) {
// Fast-path evaluations of integer literals, since we sometimes see files
// containing vast quantities of these.
if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) {
  Result.Val = APValue(APSInt(L->getValue(),
                              L->getType()->isUnsignedIntegerType()));
  IsConst = true;
  return true;
}

// This case should be rare, but we need to check it before we check on
// the type below.
if (Exp->getType().isNull()) {
  IsConst = false;
  return true;
}

// FIXME: Evaluating values of large array and record types can cause
// performance problems. Only do so in C++11 for now.
if (Exp->isPRValue() &&
    (Exp->getType()->isArrayType() || Exp->getType()->isRecordType()) &&
    !Ctx.getLangOpts().CPlusPlus11) {
  IsConst = false;
  return true;
}
return false;
14693}

14695static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
                                    Expr::SideEffectsKind SEK) {
return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
       (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
14699}

14701static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result,
                           const ASTContext &Ctx, EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
bool IsConst;
if (FastEvaluateAsRValue(E, Result, Ctx, IsConst))
  return IsConst;

return EvaluateAsRValue(Info, E, Result.Val);
14709}

14711static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult,
                        const ASTContext &Ctx,
                        Expr::SideEffectsKind AllowSideEffects,
                        EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
if (!E->getType()->isIntegralOrEnumerationType())
  return false;

if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info) ||
    !ExprResult.Val.isInt() ||
    hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
  return false;

return true;
14725}

14727static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
                               const ASTContext &Ctx,
                               Expr::SideEffectsKind AllowSideEffects,
                               EvalInfo &Info) {
assert(!E->isValueDependent())((void)0);
if (!E->getType()->isFixedPointType())
  return false;

if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info))
  return false;

if (!ExprResult.Val.isFixedPoint() ||
    hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
  return false;

return true;
14743}

14745/// EvaluateAsRValue - Return true if this is a constant which we can fold using
14746/// any crazy technique (that has nothing to do with language standards) that
14747/// we want to.  If this function returns true, it returns the folded constant
14748/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
14749/// will be applied to the result.
14750bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
                          bool InConstantContext) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);
EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
Info.InConstantContext = InConstantContext;
return ::EvaluateAsRValue(this, Result, Ctx, Info);
14757}

14759bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx,
                                    bool InConstantContext) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);
EvalResult Scratch;
return EvaluateAsRValue(Scratch, Ctx, InConstantContext) &&
       HandleConversionToBool(Scratch.Val, Result);
14766}

14768bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
                       SideEffectsKind AllowSideEffects,
                       bool InConstantContext) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);
EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
Info.InConstantContext = InConstantContext;
return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info);
14776}

14778bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
                              SideEffectsKind AllowSideEffects,
                              bool InConstantContext) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);
EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
Info.InConstantContext = InConstantContext;
return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info);
14786}

14788bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
                         SideEffectsKind AllowSideEffects,
                         bool InConstantContext) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

if (!getType()->isRealFloatingType())
  return false;

EvalResult ExprResult;
if (!EvaluateAsRValue(ExprResult, Ctx, InConstantContext) ||
    !ExprResult.Val.isFloat() ||
    hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
  return false;

Result = ExprResult.Val.getFloat();
return true;
14805}

14807bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx,
                          bool InConstantContext) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
Info.InConstantContext = InConstantContext;
LValue LV;
CheckedTemporaries CheckedTemps;
if (!EvaluateLValue(this, LV, Info) || !Info.discardCleanups() ||
    Result.HasSideEffects ||
    !CheckLValueConstantExpression(Info, getExprLoc(),
                                   Ctx.getLValueReferenceType(getType()), LV,
                                   ConstantExprKind::Normal, CheckedTemps))
  return false;

LV.moveInto(Result.Val);
return true;
14825}

14827static bool EvaluateDestruction(const ASTContext &Ctx, APValue::LValueBase Base,
                              APValue DestroyedValue, QualType Type,
                              SourceLocation Loc, Expr::EvalStatus &EStatus,
                              bool IsConstantDestruction) {
EvalInfo Info(Ctx, EStatus,
              IsConstantDestruction ? EvalInfo::EM_ConstantExpression
                                    : EvalInfo::EM_ConstantFold);
Info.setEvaluatingDecl(Base, DestroyedValue,
                       EvalInfo::EvaluatingDeclKind::Dtor);
Info.InConstantContext = IsConstantDestruction;

LValue LVal;
LVal.set(Base);

if (!HandleDestruction(Info, Loc, Base, DestroyedValue, Type) ||
    EStatus.HasSideEffects)
  return false;

if (!Info.discardCleanups())
  llvm_unreachable("Unhandled cleanup; missing full expression marker?")__builtin_unreachable();

return true;
14849}

14851bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx,
                                ConstantExprKind Kind) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
EvalInfo Info(Ctx, Result, EM);
Info.InConstantContext = true;

// The type of the object we're initializing is 'const T' for a class NTTP.
QualType T = getType();
if (Kind == ConstantExprKind::ClassTemplateArgument)
  T.addConst();

// If we're evaluating a prvalue, fake up a MaterializeTemporaryExpr to
// represent the result of the evaluation. CheckConstantExpression ensures
// this doesn't escape.
MaterializeTemporaryExpr BaseMTE(T, const_cast<Expr*>(this), true);
APValue::LValueBase Base(&BaseMTE);

Info.setEvaluatingDecl(Base, Result.Val);
LValue LVal;
LVal.set(Base);

if (!::EvaluateInPlace(Result.Val, Info, LVal, this) || Result.HasSideEffects)
  return false;

if (!Info.discardCleanups())
  llvm_unreachable("Unhandled cleanup; missing full expression marker?")__builtin_unreachable();

if (!CheckConstantExpression(Info, getExprLoc(), getStorageType(Ctx, this),
                             Result.Val, Kind))
  return false;
if (!CheckMemoryLeaks(Info))
  return false;

// If this is a class template argument, it's required to have constant
// destruction too.
if (Kind == ConstantExprKind::ClassTemplateArgument &&
    (!EvaluateDestruction(Ctx, Base, Result.Val, T, getBeginLoc(), Result,
                          true) ||
     Result.HasSideEffects)) {
  // FIXME: Prefix a note to indicate that the problem is lack of constant
  // destruction.
  return false;
}

return true;
14899}

14901bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
                               const VarDecl *VD,
                               SmallVectorImpl<PartialDiagnosticAt> &Notes,
                               bool IsConstantInitialization) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

// FIXME: Evaluating initializers for large array and record types can cause
// performance problems. Only do so in C++11 for now.
if (isPRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
    !Ctx.getLangOpts().CPlusPlus11)
  return false;

Expr::EvalStatus EStatus;
EStatus.Diag = &Notes;

EvalInfo Info(Ctx, EStatus,
              (IsConstantInitialization && Ctx.getLangOpts().CPlusPlus11)
                  ? EvalInfo::EM_ConstantExpression
                  : EvalInfo::EM_ConstantFold);
Info.setEvaluatingDecl(VD, Value);
Info.InConstantContext = IsConstantInitialization;

SourceLocation DeclLoc = VD->getLocation();
QualType DeclTy = VD->getType();

if (Info.EnableNewConstInterp) {
  auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
  if (!InterpCtx.evaluateAsInitializer(Info, VD, Value))
    return false;
} else {
  LValue LVal;
  LVal.set(VD);

  if (!EvaluateInPlace(Value, Info, LVal, this,
                       /*AllowNonLiteralTypes=*/true) ||
      EStatus.HasSideEffects)
    return false;

  // At this point, any lifetime-extended temporaries are completely
  // initialized.
  Info.performLifetimeExtension();

  if (!Info.discardCleanups())
    llvm_unreachable("Unhandled cleanup; missing full expression marker?")__builtin_unreachable();
}
return CheckConstantExpression(Info, DeclLoc, DeclTy, Value,
                               ConstantExprKind::Normal) &&
       CheckMemoryLeaks(Info);
14950}

14952bool VarDecl::evaluateDestruction(
  SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
Expr::EvalStatus EStatus;
EStatus.Diag = &Notes;

// Only treat the destruction as constant destruction if we formally have
// constant initialization (or are usable in a constant expression).
bool IsConstantDestruction = hasConstantInitialization();

// Make a copy of the value for the destructor to mutate, if we know it.
// Otherwise, treat the value as default-initialized; if the destructor works
// anyway, then the destruction is constant (and must be essentially empty).
APValue DestroyedValue;
if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent())
  DestroyedValue = *getEvaluatedValue();
else if (!getDefaultInitValue(getType(), DestroyedValue))
  return false;

if (!EvaluateDestruction(getASTContext(), this, std::move(DestroyedValue),
                         getType(), getLocation(), EStatus,
                         IsConstantDestruction) ||
    EStatus.HasSideEffects)
  return false;

ensureEvaluatedStmt()->HasConstantDestruction = true;
return true;
14978}

14980/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
14981/// constant folded, but discard the result.
14982bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

EvalResult Result;
return EvaluateAsRValue(Result, Ctx, /* in constant context */ true) &&
       !hasUnacceptableSideEffect(Result, SEK);
14989}

14991APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
                  SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

EvalResult EVResult;
EVResult.Diag = Diag;
EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
Info.InConstantContext = true;

bool Result = ::EvaluateAsRValue(this, EVResult, Ctx, Info);
(void)Result;
assert(Result && "Could not evaluate expression")((void)0);
assert(EVResult.Val.isInt() && "Expression did not evaluate to integer")((void)0);

return EVResult.Val.getInt();
15007}

15009APSInt Expr::EvaluateKnownConstIntCheckOverflow(
  const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

EvalResult EVResult;
EVResult.Diag = Diag;
EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
Info.InConstantContext = true;
Info.CheckingForUndefinedBehavior = true;

bool Result = ::EvaluateAsRValue(Info, this, EVResult.Val);
(void)Result;
assert(Result && "Could not evaluate expression")((void)0);
assert(EVResult.Val.isInt() && "Expression did not evaluate to integer")((void)0);

return EVResult.Val.getInt();
15026}

15028void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

bool IsConst;
EvalResult EVResult;
if (!FastEvaluateAsRValue(this, EVResult, Ctx, IsConst)) {
  EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
  Info.CheckingForUndefinedBehavior = true;
  (void)::EvaluateAsRValue(Info, this, EVResult.Val);
}
15039}

15041bool Expr::EvalResult::isGlobalLValue() const {
assert(Val.isLValue())((void)0);
return IsGlobalLValue(Val.getLValueBase());
15044}

15046/// isIntegerConstantExpr - this recursive routine will test if an expression is
15047/// an integer constant expression.

15049/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
15050/// comma, etc

15052// CheckICE - This function does the fundamental ICE checking: the returned
15053// ICEDiag contains an ICEKind indicating whether the expression is an ICE,
15054// and a (possibly null) SourceLocation indicating the location of the problem.
15055//
15056// Note that to reduce code duplication, this helper does no evaluation
15057// itself; the caller checks whether the expression is evaluatable, and
15058// in the rare cases where CheckICE actually cares about the evaluated
15059// value, it calls into Evaluate.

15061namespace {

15063enum ICEKind {
/// This expression is an ICE.
IK_ICE,
/// This expression is not an ICE, but if it isn't evaluated, it's
/// a legal subexpression for an ICE. This return value is used to handle
/// the comma operator in C99 mode, and non-constant subexpressions.
IK_ICEIfUnevaluated,
/// This expression is not an ICE, and is not a legal subexpression for one.
IK_NotICE
15072};

15074struct ICEDiag {
ICEKind Kind;
SourceLocation Loc;

ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
15079};

15081}

15083static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }

15085static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }

15087static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
Expr::EvalResult EVResult;
Expr::EvalStatus Status;
EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);

Info.InConstantContext = true;
if (!::EvaluateAsRValue(E, EVResult, Ctx, Info) || EVResult.HasSideEffects ||
    !EVResult.Val.isInt())
  return ICEDiag(IK_NotICE, E->getBeginLoc());

return NoDiag();
15098}

15100static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
assert(!E->isValueDependent() && "Should not see value dependent exprs!")((void)0);
if (!E->getType()->isIntegralOrEnumerationType())
  return ICEDiag(IK_NotICE, E->getBeginLoc());

switch (E->getStmtClass()) {
15106#define ABSTRACT_STMT(Node)
15107#define STMT(Node, Base) case Expr::Node##Class:
15108#define EXPR(Node, Base)
15109#include "clang/AST/StmtNodes.inc"
case Expr::PredefinedExprClass:
case Expr::FloatingLiteralClass:
case Expr::ImaginaryLiteralClass:
case Expr::StringLiteralClass:
case Expr::ArraySubscriptExprClass:
case Expr::MatrixSubscriptExprClass:
case Expr::OMPArraySectionExprClass:
case Expr::OMPArrayShapingExprClass:
case Expr::OMPIteratorExprClass:
case Expr::MemberExprClass:
case Expr::CompoundAssignOperatorClass:
case Expr::CompoundLiteralExprClass:
case Expr::ExtVectorElementExprClass:
case Expr::DesignatedInitExprClass:
case Expr::ArrayInitLoopExprClass:
case Expr::ArrayInitIndexExprClass:
case Expr::NoInitExprClass:
case Expr::DesignatedInitUpdateExprClass:
case Expr::ImplicitValueInitExprClass:
case Expr::ParenListExprClass:
case Expr::VAArgExprClass:
case Expr::AddrLabelExprClass:
case Expr::StmtExprClass:
case Expr::CXXMemberCallExprClass:
case Expr::CUDAKernelCallExprClass:
case Expr::CXXAddrspaceCastExprClass:
case Expr::CXXDynamicCastExprClass:
case Expr::CXXTypeidExprClass:
case Expr::CXXUuidofExprClass:
case Expr::MSPropertyRefExprClass:
case Expr::MSPropertySubscriptExprClass:
case Expr::CXXNullPtrLiteralExprClass:
case Expr::UserDefinedLiteralClass:
case Expr::CXXThisExprClass:
case Expr::CXXThrowExprClass:
case Expr::CXXNewExprClass:
case Expr::CXXDeleteExprClass:
case Expr::CXXPseudoDestructorExprClass:
case Expr::UnresolvedLookupExprClass:
case Expr::TypoExprClass:
case Expr::RecoveryExprClass:
case Expr::DependentScopeDeclRefExprClass:
case Expr::CXXConstructExprClass:
case Expr::CXXInheritedCtorInitExprClass:
case Expr::CXXStdInitializerListExprClass:
case Expr::CXXBindTemporaryExprClass:
case Expr::ExprWithCleanupsClass:
case Expr::CXXTemporaryObjectExprClass:
case Expr::CXXUnresolvedConstructExprClass:
case Expr::CXXDependentScopeMemberExprClass:
case Expr::UnresolvedMemberExprClass:
case Expr::ObjCStringLiteralClass:
case Expr::ObjCBoxedExprClass:
case Expr::ObjCArrayLiteralClass:
case Expr::ObjCDictionaryLiteralClass:
case Expr::ObjCEncodeExprClass:
case Expr::ObjCMessageExprClass:
case Expr::ObjCSelectorExprClass:
case Expr::ObjCProtocolExprClass:
case Expr::ObjCIvarRefExprClass:
case Expr::ObjCPropertyRefExprClass:
case Expr::ObjCSubscriptRefExprClass:
case Expr::ObjCIsaExprClass:
case Expr::ObjCAvailabilityCheckExprClass:
case Expr::ShuffleVectorExprClass:
case Expr::ConvertVectorExprClass:
case Expr::BlockExprClass:
case Expr::NoStmtClass:
case Expr::OpaqueValueExprClass:
case Expr::PackExpansionExprClass:
case Expr::SubstNonTypeTemplateParmPackExprClass:
case Expr::FunctionParmPackExprClass:
case Expr::AsTypeExprClass:
case Expr::ObjCIndirectCopyRestoreExprClass:
case Expr::MaterializeTemporaryExprClass:
case Expr::PseudoObjectExprClass:
case Expr::AtomicExprClass:
case Expr::LambdaExprClass:
case Expr::CXXFoldExprClass:
case Expr::CoawaitExprClass:
case Expr::DependentCoawaitExprClass:
case Expr::CoyieldExprClass:
case Expr::SYCLUniqueStableNameExprClass:
  return ICEDiag(IK_NotICE, E->getBeginLoc());

case Expr::InitListExprClass: {
  // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
  // form "T x = { a };" is equivalent to "T x = a;".
  // Unless we're initializing a reference, T is a scalar as it is known to be
  // of integral or enumeration type.
  if (E->isPRValue())
    if (cast<InitListExpr>(E)->getNumInits() == 1)
      return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
  return ICEDiag(IK_NotICE, E->getBeginLoc());
}

case Expr::SizeOfPackExprClass:
case Expr::GNUNullExprClass:
case Expr::SourceLocExprClass:
  return NoDiag();

case Expr::SubstNonTypeTemplateParmExprClass:
  return
    CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);

case Expr::ConstantExprClass:
  return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx);

case Expr::ParenExprClass:
  return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
case Expr::GenericSelectionExprClass:
  return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
case Expr::IntegerLiteralClass:
case Expr::FixedPointLiteralClass:
case Expr::CharacterLiteralClass:
case Expr::ObjCBoolLiteralExprClass:
case Expr::CXXBoolLiteralExprClass:
case Expr::CXXScalarValueInitExprClass:
case Expr::TypeTraitExprClass:
case Expr::ConceptSpecializationExprClass:
case Expr::RequiresExprClass:
case Expr::ArrayTypeTraitExprClass:
case Expr::ExpressionTraitExprClass:
case Expr::CXXNoexceptExprClass:
  return NoDiag();
case Expr::CallExprClass:
case Expr::CXXOperatorCallExprClass: {
  // C99 6.6/3 allows function calls within unevaluated subexpressions of
  // constant expressions, but they can never be ICEs because an ICE cannot
  // contain an operand of (pointer to) function type.
  const CallExpr *CE = cast<CallExpr>(E);
  if (CE->getBuiltinCallee())
    return CheckEvalInICE(E, Ctx);
  return ICEDiag(IK_NotICE, E->getBeginLoc());
}
case Expr::CXXRewrittenBinaryOperatorClass:
  return CheckICE(cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm(),
                  Ctx);
case Expr::DeclRefExprClass: {
  const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl();
  if (isa<EnumConstantDecl>(D))
    return NoDiag();

  // C++ and OpenCL (FIXME: spec reference?) allow reading const-qualified
  // integer variables in constant expressions:
  //
  // C++ 7.1.5.1p2
  //   A variable of non-volatile const-qualified integral or enumeration
  //   type initialized by an ICE can be used in ICEs.
  //
  // We sometimes use CheckICE to check the C++98 rules in C++11 mode. In
  // that mode, use of reference variables should not be allowed.
  const VarDecl *VD = dyn_cast<VarDecl>(D);
  if (VD && VD->isUsableInConstantExpressions(Ctx) &&
      !VD->getType()->isReferenceType())
    return NoDiag();

  return ICEDiag(IK_NotICE, E->getBeginLoc());
}
case Expr::UnaryOperatorClass: {
  const UnaryOperator *Exp = cast<UnaryOperator>(E);
  switch (Exp->getOpcode()) {
  case UO_PostInc:
  case UO_PostDec:
  case UO_PreInc:
  case UO_PreDec:
  case UO_AddrOf:
  case UO_Deref:
  case UO_Coawait:
    // C99 6.6/3 allows increment and decrement within unevaluated
    // subexpressions of constant expressions, but they can never be ICEs
    // because an ICE cannot contain an lvalue operand.
    return ICEDiag(IK_NotICE, E->getBeginLoc());
  case UO_Extension:
  case UO_LNot:
  case UO_Plus:
  case UO_Minus:
  case UO_Not:
  case UO_Real:
  case UO_Imag:
    return CheckICE(Exp->getSubExpr(), Ctx);
  }
  llvm_unreachable("invalid unary operator class")__builtin_unreachable();
}
case Expr::OffsetOfExprClass: {
  // Note that per C99, offsetof must be an ICE. And AFAIK, using
  // EvaluateAsRValue matches the proposed gcc behavior for cases like
  // "offsetof(struct s{int x[4];}, x[1.0])".  This doesn't affect
  // compliance: we should warn earlier for offsetof expressions with
  // array subscripts that aren't ICEs, and if the array subscripts
  // are ICEs, the value of the offsetof must be an integer constant.
  return CheckEvalInICE(E, Ctx);
}
case Expr::UnaryExprOrTypeTraitExprClass: {
  const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
  if ((Exp->getKind() ==  UETT_SizeOf) &&
      Exp->getTypeOfArgument()->isVariableArrayType())
    return ICEDiag(IK_NotICE, E->getBeginLoc());
  return NoDiag();
}
case Expr::BinaryOperatorClass: {
  const BinaryOperator *Exp = cast<BinaryOperator>(E);
  switch (Exp->getOpcode()) {
  case BO_PtrMemD:
  case BO_PtrMemI:
  case BO_Assign:
  case BO_MulAssign:
  case BO_DivAssign:
  case BO_RemAssign:
  case BO_AddAssign:
  case BO_SubAssign:
  case BO_ShlAssign:
  case BO_ShrAssign:
  case BO_AndAssign:
  case BO_XorAssign:
  case BO_OrAssign:
    // C99 6.6/3 allows assignments within unevaluated subexpressions of
    // constant expressions, but they can never be ICEs because an ICE cannot
    // contain an lvalue operand.
    return ICEDiag(IK_NotICE, E->getBeginLoc());

  case BO_Mul:
  case BO_Div:
  case BO_Rem:
  case BO_Add:
  case BO_Sub:
  case BO_Shl:
  case BO_Shr:
  case BO_LT:
  case BO_GT:
  case BO_LE:
  case BO_GE:
  case BO_EQ:
  case BO_NE:
  case BO_And:
  case BO_Xor:
  case BO_Or:
  case BO_Comma:
  case BO_Cmp: {
    ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
    ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
    if (Exp->getOpcode() == BO_Div ||
        Exp->getOpcode() == BO_Rem) {
      // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
      // we don't evaluate one.
      if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
        llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
        if (REval == 0)
          return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
        if (REval.isSigned() && REval.isAllOnesValue()) {
          llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
          if (LEval.isMinSignedValue())
            return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
        }
      }
    }
    if (Exp->getOpcode() == BO_Comma) {
      if (Ctx.getLangOpts().C99) {
        // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
        // if it isn't evaluated.
        if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
          return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
      } else {
        // In both C89 and C++, commas in ICEs are illegal.
        return ICEDiag(IK_NotICE, E->getBeginLoc());
      }
    }
    return Worst(LHSResult, RHSResult);
  }
  case BO_LAnd:
  case BO_LOr: {
    ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
    ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
    if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
      // Rare case where the RHS has a comma "side-effect"; we need
      // to actually check the condition to see whether the side
      // with the comma is evaluated.
      if ((Exp->getOpcode() == BO_LAnd) !=
          (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
        return RHSResult;
      return NoDiag();
    }

    return Worst(LHSResult, RHSResult);
  }
  }
  llvm_unreachable("invalid binary operator kind")__builtin_unreachable();
}
case Expr::ImplicitCastExprClass:
case Expr::CStyleCastExprClass:
case Expr::CXXFunctionalCastExprClass:
case Expr::CXXStaticCastExprClass:
case Expr::CXXReinterpretCastExprClass:
case Expr::CXXConstCastExprClass:
case Expr::ObjCBridgedCastExprClass: {
  const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
  if (isa<ExplicitCastExpr>(E)) {
    if (const FloatingLiteral *FL
          = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
      unsigned DestWidth = Ctx.getIntWidth(E->getType());
      bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
      APSInt IgnoredVal(DestWidth, !DestSigned);
      bool Ignored;
      // If the value does not fit in the destination type, the behavior is
      // undefined, so we are not required to treat it as a constant
      // expression.
      if (FL->getValue().convertToInteger(IgnoredVal,
                                          llvm::APFloat::rmTowardZero,
                                          &Ignored) & APFloat::opInvalidOp)
        return ICEDiag(IK_NotICE, E->getBeginLoc());
      return NoDiag();
    }
  }
  switch (cast<CastExpr>(E)->getCastKind()) {
  case CK_LValueToRValue:
  case CK_AtomicToNonAtomic:
  case CK_NonAtomicToAtomic:
  case CK_NoOp:
  case CK_IntegralToBoolean:
  case CK_IntegralCast:
    return CheckICE(SubExpr, Ctx);
  default:
    return ICEDiag(IK_NotICE, E->getBeginLoc());
  }
}
case Expr::BinaryConditionalOperatorClass: {
  const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
  ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
  if (CommonResult.Kind == IK_NotICE) return CommonResult;
  ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
  if (FalseResult.Kind == IK_NotICE) return FalseResult;
  if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
  if (FalseResult.Kind == IK_ICEIfUnevaluated &&
      Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
  return FalseResult;
}
case Expr::ConditionalOperatorClass: {
  const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
  // If the condition (ignoring parens) is a __builtin_constant_p call,
  // then only the true side is actually considered in an integer constant
  // expression, and it is fully evaluated.  This is an important GNU
  // extension.  See GCC PR38377 for discussion.
  if (const CallExpr *CallCE
      = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
    if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
      return CheckEvalInICE(E, Ctx);
  ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
  if (CondResult.Kind == IK_NotICE)
    return CondResult;

  ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
  ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);

  if (TrueResult.Kind == IK_NotICE)
    return TrueResult;
  if (FalseResult.Kind == IK_NotICE)
    return FalseResult;
  if (CondResult.Kind == IK_ICEIfUnevaluated)
    return CondResult;
  if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
    return NoDiag();
  // Rare case where the diagnostics depend on which side is evaluated
  // Note that if we get here, CondResult is 0, and at least one of
  // TrueResult and FalseResult is non-zero.
  if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
    return FalseResult;
  return TrueResult;
}
case Expr::CXXDefaultArgExprClass:
  return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
case Expr::CXXDefaultInitExprClass:
  return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
case Expr::ChooseExprClass: {
  return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
}
case Expr::BuiltinBitCastExprClass: {
  if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E)))
    return ICEDiag(IK_NotICE, E->getBeginLoc());
  return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx);
}
}

llvm_unreachable("Invalid StmtClass!")__builtin_unreachable();
15493}

15495/// Evaluate an expression as a C++11 integral constant expression.
15496static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
                                                  const Expr *E,
                                                  llvm::APSInt *Value,
                                                  SourceLocation *Loc) {
if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
  if (Loc) *Loc = E->getExprLoc();
  return false;
}

APValue Result;
if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
  return false;

if (!Result.isInt()) {
  if (Loc) *Loc = E->getExprLoc();
  return false;
}

if (Value) *Value = Result.getInt();
return true;
15516}

15518bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
                               SourceLocation *Loc) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

if (Ctx.getLangOpts().CPlusPlus11)
  return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);

ICEDiag D = CheckICE(this, Ctx);
if (D.Kind != IK_ICE) {
  if (Loc) *Loc = D.Loc;
  return false;
}
return true;
15532}

15534Optional<llvm::APSInt> Expr::getIntegerConstantExpr(const ASTContext &Ctx,
                                                  SourceLocation *Loc,
                                                  bool isEvaluated) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

APSInt Value;

if (Ctx.getLangOpts().CPlusPlus11) {
  if (EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc))
    return Value;
  return None;
}

if (!isIntegerConstantExpr(Ctx, Loc))
  return None;

// The only possible side-effects here are due to UB discovered in the
// evaluation (for instance, INT_MAX + 1). In such a case, we are still
// required to treat the expression as an ICE, so we produce the folded
// value.
EvalResult ExprResult;
Expr::EvalStatus Status;
EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects);
Info.InConstantContext = true;

if (!::EvaluateAsInt(this, ExprResult, Ctx, SE_AllowSideEffects, Info))
  llvm_unreachable("ICE cannot be evaluated!")__builtin_unreachable();

return ExprResult.Val.getInt();
15564}

15566bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

return CheckICE(this, Ctx).Kind == IK_ICE;
15571}

15573bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
                             SourceLocation *Loc) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

// We support this checking in C++98 mode in order to diagnose compatibility
// issues.
assert(Ctx.getLangOpts().CPlusPlus)((void)0);

// Build evaluation settings.
Expr::EvalStatus Status;
SmallVector<PartialDiagnosticAt, 8> Diags;
Status.Diag = &Diags;
EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);

APValue Scratch;
bool IsConstExpr =
    ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch) &&
    // FIXME: We don't produce a diagnostic for this, but the callers that
    // call us on arbitrary full-expressions should generally not care.
    Info.discardCleanups() && !Status.HasSideEffects;

if (!Diags.empty()) {
  IsConstExpr = false;
  if (Loc) *Loc = Diags[0].first;
} else if (!IsConstExpr) {
  // FIXME: This shouldn't happen.
  if (Loc) *Loc = getExprLoc();
}

return IsConstExpr;
15604}

15606bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
                                  const FunctionDecl *Callee,
                                  ArrayRef<const Expr*> Args,
                                  const Expr *This) const {
assert(!isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

Expr::EvalStatus Status;
EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
Info.InConstantContext = true;

LValue ThisVal;
const LValue *ThisPtr = nullptr;
if (This) {
15620#ifndef NDEBUG1
  auto *MD = dyn_cast<CXXMethodDecl>(Callee);
  assert(MD && "Don't provide `this` for non-methods.")((void)0);
  assert(!MD->isStatic() && "Don't provide `this` for static methods.")((void)0);
15624#endif
  if (!This->isValueDependent() &&
      EvaluateObjectArgument(Info, This, ThisVal) &&
      !Info.EvalStatus.HasSideEffects)
    ThisPtr = &ThisVal;

  // Ignore any side-effects from a failed evaluation. This is safe because
  // they can't interfere with any other argument evaluation.
  Info.EvalStatus.HasSideEffects = false;
}

CallRef Call = Info.CurrentCall->createCall(Callee);
for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
     I != E; ++I) {
  unsigned Idx = I - Args.begin();
  if (Idx >= Callee->getNumParams())
    break;
  const ParmVarDecl *PVD = Callee->getParamDecl(Idx);
  if ((*I)->isValueDependent() ||
      !EvaluateCallArg(PVD, *I, Call, Info) ||
      Info.EvalStatus.HasSideEffects) {
    // If evaluation fails, throw away the argument entirely.
    if (APValue *Slot = Info.getParamSlot(Call, PVD))
      *Slot = APValue();
  }

  // Ignore any side-effects from a failed evaluation. This is safe because
  // they can't interfere with any other argument evaluation.
  Info.EvalStatus.HasSideEffects = false;
}

// Parameter cleanups happen in the caller and are not part of this
// evaluation.
Info.discardCleanups();
Info.EvalStatus.HasSideEffects = false;

// Build fake call to Callee.
CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr, Call);
// FIXME: Missing ExprWithCleanups in enable_if conditions?
FullExpressionRAII Scope(Info);
return Evaluate(Value, Info, this) && Scope.destroy() &&
       !Info.EvalStatus.HasSideEffects;
15666}

15668bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
                                 SmallVectorImpl<
                                   PartialDiagnosticAt> &Diags) {
// FIXME: It would be useful to check constexpr function templates, but at the
// moment the constant expression evaluator cannot cope with the non-rigorous
// ASTs which we build for dependent expressions.
if (FD->isDependentContext())
1
Assuming the condition is false→
2
←
Taking false branch→
  return true;

Expr::EvalStatus Status;
Status.Diag = &Diags;

EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression);
3
←
Calling constructor for 'EvalInfo'→
6
←
Returning from constructor for 'EvalInfo'→
Info.InConstantContext = true;
Info.CheckingPotentialConstantExpression = true;

// The constexpr VM attempts to compile all methods to bytecode here.
if (Info.EnableNewConstInterp) {
7
←
Assuming field 'EnableNewConstInterp' is false→
8
←
Taking false branch→
  Info.Ctx.getInterpContext().isPotentialConstantExpr(Info, FD);
  return Diags.empty();
}

const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
9
←
Assuming 'FD' is a 'CXXMethodDecl'→
const CXXRecordDecl *RD = MD9.1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
 ? MD->getParent()->getCanonicalDecl() : nullptr;
10
←
'?' condition is true→

// Fabricate an arbitrary expression on the stack and pretend that it
// is a temporary being used as the 'this' pointer.
LValue This;
ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
11
←
Assuming 'RD' is non-null→
12
←
'?' condition is true→
This.set({&VIE, Info.CurrentCall->Index});

ArrayRef<const Expr*> Args;

APValue Scratch;
if (const CXXConstructorDecl *CD13.1
'CD' is null
1
'CD' is null
1
'CD' is null
1
'CD' is null
1
'CD' is null
1
'CD' is null
 = dyn_cast<CXXConstructorDecl>(FD)) {
13
←
Assuming 'FD' is not a 'CXXConstructorDecl'→
14
←
Taking false branch→
  // Evaluate the call as a constant initializer, to allow the construction
  // of objects of non-literal types.
  Info.setEvaluatingDecl(This.getLValueBase(), Scratch);
  HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
} else {
  SourceLocation Loc = FD->getLocation();
  HandleFunctionCall(Loc, FD, (MD14.1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
1
'MD' is non-null
 && MD->isInstance()) ? &This : nullptr,
15
←
'?' condition is true→
16
←
Calling 'HandleFunctionCall'→
                     Args, CallRef(), FD->getBody(), Info, Scratch, nullptr);
}

return Diags.empty();
15714}

15716bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
                                            const FunctionDecl *FD,
                                            SmallVectorImpl<
                                              PartialDiagnosticAt> &Diags) {
assert(!E->isValueDependent() &&((void)0)
       "Expression evaluator can't be called on a dependent expression.")((void)0);

Expr::EvalStatus Status;
Status.Diag = &Diags;

EvalInfo Info(FD->getASTContext(), Status,
              EvalInfo::EM_ConstantExpressionUnevaluated);
Info.InConstantContext = true;
Info.CheckingPotentialConstantExpression = true;

// Fabricate a call stack frame to give the arguments a plausible cover story.
CallStackFrame Frame(Info, SourceLocation(), FD, /*This*/ nullptr, CallRef());

APValue ResultScratch;
Evaluate(ResultScratch, Info, E);
return Diags.empty();
15737}

15739bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
                               unsigned Type) const {
if (!getType()->isPointerType())
  return false;

Expr::EvalStatus Status;
EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
return tryEvaluateBuiltinObjectSize(this, Type, Info, Result);
15747}

←

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/include/clang/AST/Decl.h

→

1//===- Decl.h - Classes for representing declarations -----------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file defines the Decl subclasses.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_CLANG_AST_DECL_H
14#define LLVM_CLANG_AST_DECL_H

16#include "clang/AST/APValue.h"
17#include "clang/AST/ASTContextAllocate.h"
18#include "clang/AST/DeclAccessPair.h"
19#include "clang/AST/DeclBase.h"
20#include "clang/AST/DeclarationName.h"
21#include "clang/AST/ExternalASTSource.h"
22#include "clang/AST/NestedNameSpecifier.h"
23#include "clang/AST/Redeclarable.h"
24#include "clang/AST/Type.h"
25#include "clang/Basic/AddressSpaces.h"
26#include "clang/Basic/Diagnostic.h"
27#include "clang/Basic/IdentifierTable.h"
28#include "clang/Basic/LLVM.h"
29#include "clang/Basic/Linkage.h"
30#include "clang/Basic/OperatorKinds.h"
31#include "clang/Basic/PartialDiagnostic.h"
32#include "clang/Basic/PragmaKinds.h"
33#include "clang/Basic/SourceLocation.h"
34#include "clang/Basic/Specifiers.h"
35#include "clang/Basic/Visibility.h"
36#include "llvm/ADT/APSInt.h"
37#include "llvm/ADT/ArrayRef.h"
38#include "llvm/ADT/Optional.h"
39#include "llvm/ADT/PointerIntPair.h"
40#include "llvm/ADT/PointerUnion.h"
41#include "llvm/ADT/StringRef.h"
42#include "llvm/ADT/iterator_range.h"
43#include "llvm/Support/Casting.h"
44#include "llvm/Support/Compiler.h"
45#include "llvm/Support/TrailingObjects.h"
46#include <cassert>
47#include <cstddef>
48#include <cstdint>
49#include <string>
50#include <utility>

52namespace clang {

54class ASTContext;
55struct ASTTemplateArgumentListInfo;
56class Attr;
57class CompoundStmt;
58class DependentFunctionTemplateSpecializationInfo;
59class EnumDecl;
60class Expr;
61class FunctionTemplateDecl;
62class FunctionTemplateSpecializationInfo;
63class FunctionTypeLoc;
64class LabelStmt;
65class MemberSpecializationInfo;
66class Module;
67class NamespaceDecl;
68class ParmVarDecl;
69class RecordDecl;
70class Stmt;
71class StringLiteral;
72class TagDecl;
73class TemplateArgumentList;
74class TemplateArgumentListInfo;
75class TemplateParameterList;
76class TypeAliasTemplateDecl;
77class TypeLoc;
78class UnresolvedSetImpl;
79class VarTemplateDecl;

81/// The top declaration context.
82class TranslationUnitDecl : public Decl,
                          public DeclContext,
                          public Redeclarable<TranslationUnitDecl> {
using redeclarable_base = Redeclarable<TranslationUnitDecl>;

TranslationUnitDecl *getNextRedeclarationImpl() override {
  return getNextRedeclaration();
}

TranslationUnitDecl *getPreviousDeclImpl() override {
  return getPreviousDecl();
}

TranslationUnitDecl *getMostRecentDeclImpl() override {
  return getMostRecentDecl();
}

ASTContext &Ctx;

/// The (most recently entered) anonymous namespace for this
/// translation unit, if one has been created.
NamespaceDecl *AnonymousNamespace = nullptr;

explicit TranslationUnitDecl(ASTContext &ctx);

virtual void anchor();

109public:
using redecl_range = redeclarable_base::redecl_range;
using redecl_iterator = redeclarable_base::redecl_iterator;

using redeclarable_base::getMostRecentDecl;
using redeclarable_base::getPreviousDecl;
using redeclarable_base::isFirstDecl;
using redeclarable_base::redecls;
using redeclarable_base::redecls_begin;
using redeclarable_base::redecls_end;

ASTContext &getASTContext() const { return Ctx; }

NamespaceDecl *getAnonymousNamespace() const { return AnonymousNamespace; }
void setAnonymousNamespace(NamespaceDecl *D) { AnonymousNamespace = D; }

static TranslationUnitDecl *Create(ASTContext &C);

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == TranslationUnit; }
static DeclContext *castToDeclContext(const TranslationUnitDecl *D) {
  return static_cast<DeclContext *>(const_cast<TranslationUnitDecl*>(D));
}
static TranslationUnitDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<TranslationUnitDecl *>(const_cast<DeclContext*>(DC));
}
136};

138/// Represents a `#pragma comment` line. Always a child of
139/// TranslationUnitDecl.
140class PragmaCommentDecl final
  : public Decl,
    private llvm::TrailingObjects<PragmaCommentDecl, char> {
friend class ASTDeclReader;
friend class ASTDeclWriter;
friend TrailingObjects;

PragmaMSCommentKind CommentKind;

PragmaCommentDecl(TranslationUnitDecl *TU, SourceLocation CommentLoc,
                  PragmaMSCommentKind CommentKind)
    : Decl(PragmaComment, TU, CommentLoc), CommentKind(CommentKind) {}

virtual void anchor();

155public:
static PragmaCommentDecl *Create(const ASTContext &C, TranslationUnitDecl *DC,
                                 SourceLocation CommentLoc,
                                 PragmaMSCommentKind CommentKind,
                                 StringRef Arg);
static PragmaCommentDecl *CreateDeserialized(ASTContext &C, unsigned ID,
                                             unsigned ArgSize);

PragmaMSCommentKind getCommentKind() const { return CommentKind; }

StringRef getArg() const { return getTrailingObjects<char>(); }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == PragmaComment; }
170};

172/// Represents a `#pragma detect_mismatch` line. Always a child of
173/// TranslationUnitDecl.
174class PragmaDetectMismatchDecl final
  : public Decl,
    private llvm::TrailingObjects<PragmaDetectMismatchDecl, char> {
friend class ASTDeclReader;
friend class ASTDeclWriter;
friend TrailingObjects;

size_t ValueStart;

PragmaDetectMismatchDecl(TranslationUnitDecl *TU, SourceLocation Loc,
                         size_t ValueStart)
    : Decl(PragmaDetectMismatch, TU, Loc), ValueStart(ValueStart) {}

virtual void anchor();

189public:
static PragmaDetectMismatchDecl *Create(const ASTContext &C,
                                        TranslationUnitDecl *DC,
                                        SourceLocation Loc, StringRef Name,
                                        StringRef Value);
static PragmaDetectMismatchDecl *
CreateDeserialized(ASTContext &C, unsigned ID, unsigned NameValueSize);

StringRef getName() const { return getTrailingObjects<char>(); }
StringRef getValue() const { return getTrailingObjects<char>() + ValueStart; }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == PragmaDetectMismatch; }
203};

205/// Declaration context for names declared as extern "C" in C++. This
206/// is neither the semantic nor lexical context for such declarations, but is
207/// used to check for conflicts with other extern "C" declarations. Example:
208///
209/// \code
210///   namespace N { extern "C" void f(); } // #1
211///   void N::f() {}                       // #2
212///   namespace M { extern "C" void f(); } // #3
213/// \endcode
214///
215/// The semantic context of #1 is namespace N and its lexical context is the
216/// LinkageSpecDecl; the semantic context of #2 is namespace N and its lexical
217/// context is the TU. However, both declarations are also visible in the
218/// extern "C" context.
219///
220/// The declaration at #3 finds it is a redeclaration of \c N::f through
221/// lookup in the extern "C" context.
222class ExternCContextDecl : public Decl, public DeclContext {
explicit ExternCContextDecl(TranslationUnitDecl *TU)
  : Decl(ExternCContext, TU, SourceLocation()),
    DeclContext(ExternCContext) {}

virtual void anchor();

229public:
static ExternCContextDecl *Create(const ASTContext &C,
                                  TranslationUnitDecl *TU);

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == ExternCContext; }
static DeclContext *castToDeclContext(const ExternCContextDecl *D) {
  return static_cast<DeclContext *>(const_cast<ExternCContextDecl*>(D));
}
static ExternCContextDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<ExternCContextDecl *>(const_cast<DeclContext*>(DC));
}
242};

244/// This represents a decl that may have a name.  Many decls have names such
245/// as ObjCMethodDecl, but not \@class, etc.
246///
247/// Note that not every NamedDecl is actually named (e.g., a struct might
248/// be anonymous), and not every name is an identifier.
249class NamedDecl : public Decl {
/// The name of this declaration, which is typically a normal
/// identifier but may also be a special kind of name (C++
/// constructor, Objective-C selector, etc.)
DeclarationName Name;

virtual void anchor();

257private:
NamedDecl *getUnderlyingDeclImpl() LLVM_READONLY__attribute__((__pure__));

260protected:
NamedDecl(Kind DK, DeclContext *DC, SourceLocation L, DeclarationName N)
    : Decl(DK, DC, L), Name(N) {}

264public:
/// Get the identifier that names this declaration, if there is one.
///
/// This will return NULL if this declaration has no name (e.g., for
/// an unnamed class) or if the name is a special name (C++ constructor,
/// Objective-C selector, etc.).
IdentifierInfo *getIdentifier() const { return Name.getAsIdentifierInfo(); }

/// Get the name of identifier for this declaration as a StringRef.
///
/// This requires that the declaration have a name and that it be a simple
/// identifier.
StringRef getName() const {
  assert(Name.isIdentifier() && "Name is not a simple identifier")((void)0);
  return getIdentifier() ? getIdentifier()->getName() : "";
}

/// Get a human-readable name for the declaration, even if it is one of the
/// special kinds of names (C++ constructor, Objective-C selector, etc).
///
/// Creating this name requires expensive string manipulation, so it should
/// be called only when performance doesn't matter. For simple declarations,
/// getNameAsCString() should suffice.
//
// FIXME: This function should be renamed to indicate that it is not just an
// alternate form of getName(), and clients should move as appropriate.
//
// FIXME: Deprecated, move clients to getName().
std::string getNameAsString() const { return Name.getAsString(); }

/// Pretty-print the unqualified name of this declaration. Can be overloaded
/// by derived classes to provide a more user-friendly name when appropriate.
virtual void printName(raw_ostream &os) const;

/// Get the actual, stored name of the declaration, which may be a special
/// name.
///
/// Note that generally in diagnostics, the non-null \p NamedDecl* itself
/// should be sent into the diagnostic instead of using the result of
/// \p getDeclName().
///
/// A \p DeclarationName in a diagnostic will just be streamed to the output,
/// which will directly result in a call to \p DeclarationName::print.
///
/// A \p NamedDecl* in a diagnostic will also ultimately result in a call to
/// \p DeclarationName::print, but with two customisation points along the
/// way (\p getNameForDiagnostic and \p printName). These are used to print
/// the template arguments if any, and to provide a user-friendly name for
/// some entities (such as unnamed variables and anonymous records).
DeclarationName getDeclName() const { return Name; }

/// Set the name of this declaration.
void setDeclName(DeclarationName N) { Name = N; }

/// Returns a human-readable qualified name for this declaration, like
/// A::B::i, for i being member of namespace A::B.
///
/// If the declaration is not a member of context which can be named (record,
/// namespace), it will return the same result as printName().
///
/// Creating this name is expensive, so it should be called only when
/// performance doesn't matter.
void printQualifiedName(raw_ostream &OS) const;
void printQualifiedName(raw_ostream &OS, const PrintingPolicy &Policy) const;

/// Print only the nested name specifier part of a fully-qualified name,
/// including the '::' at the end. E.g.
///    when `printQualifiedName(D)` prints "A::B::i",
///    this function prints "A::B::".
void printNestedNameSpecifier(raw_ostream &OS) const;
void printNestedNameSpecifier(raw_ostream &OS,
                              const PrintingPolicy &Policy) const;

// FIXME: Remove string version.
std::string getQualifiedNameAsString() const;

/// Appends a human-readable name for this declaration into the given stream.
///
/// This is the method invoked by Sema when displaying a NamedDecl
/// in a diagnostic.  It does not necessarily produce the same
/// result as printName(); for example, class template
/// specializations are printed with their template arguments.
virtual void getNameForDiagnostic(raw_ostream &OS,
                                  const PrintingPolicy &Policy,
                                  bool Qualified) const;

/// Determine whether this declaration, if known to be well-formed within
/// its context, will replace the declaration OldD if introduced into scope.
///
/// A declaration will replace another declaration if, for example, it is
/// a redeclaration of the same variable or function, but not if it is a
/// declaration of a different kind (function vs. class) or an overloaded
/// function.
///
/// \param IsKnownNewer \c true if this declaration is known to be newer
/// than \p OldD (for instance, if this declaration is newly-created).
bool declarationReplaces(NamedDecl *OldD, bool IsKnownNewer = true) const;

/// Determine whether this declaration has linkage.
bool hasLinkage() const;

using Decl::isModulePrivate;
using Decl::setModulePrivate;

/// Determine whether this declaration is a C++ class member.
bool isCXXClassMember() const {
  const DeclContext *DC = getDeclContext();

  // C++0x [class.mem]p1:
  //   The enumerators of an unscoped enumeration defined in
  //   the class are members of the class.
  if (isa<EnumDecl>(DC))
    DC = DC->getRedeclContext();

  return DC->isRecord();
}

/// Determine whether the given declaration is an instance member of
/// a C++ class.
bool isCXXInstanceMember() const;

/// Determine if the declaration obeys the reserved identifier rules of the
/// given language.
ReservedIdentifierStatus isReserved(const LangOptions &LangOpts) const;

/// Determine what kind of linkage this entity has.
///
/// This is not the linkage as defined by the standard or the codegen notion
/// of linkage. It is just an implementation detail that is used to compute
/// those.
Linkage getLinkageInternal() const;

/// Get the linkage from a semantic point of view. Entities in
/// anonymous namespaces are external (in c++98).
Linkage getFormalLinkage() const {
  return clang::getFormalLinkage(getLinkageInternal());
}

/// True if this decl has external linkage.
bool hasExternalFormalLinkage() const {
  return isExternalFormalLinkage(getLinkageInternal());
}

bool isExternallyVisible() const {
  return clang::isExternallyVisible(getLinkageInternal());
}

/// Determine whether this declaration can be redeclared in a
/// different translation unit.
bool isExternallyDeclarable() const {
  return isExternallyVisible() && !getOwningModuleForLinkage();
}

/// Determines the visibility of this entity.
Visibility getVisibility() const {
  return getLinkageAndVisibility().getVisibility();
}

/// Determines the linkage and visibility of this entity.
LinkageInfo getLinkageAndVisibility() const;

/// Kinds of explicit visibility.
enum ExplicitVisibilityKind {
  /// Do an LV computation for, ultimately, a type.
  /// Visibility may be restricted by type visibility settings and
  /// the visibility of template arguments.
  VisibilityForType,

  /// Do an LV computation for, ultimately, a non-type declaration.
  /// Visibility may be restricted by value visibility settings and
  /// the visibility of template arguments.
  VisibilityForValue
};

/// If visibility was explicitly specified for this
/// declaration, return that visibility.
Optional<Visibility>
getExplicitVisibility(ExplicitVisibilityKind kind) const;

/// True if the computed linkage is valid. Used for consistency
/// checking. Should always return true.
bool isLinkageValid() const;

/// True if something has required us to compute the linkage
/// of this declaration.
///
/// Language features which can retroactively change linkage (like a
/// typedef name for linkage purposes) may need to consider this,
/// but hopefully only in transitory ways during parsing.
bool hasLinkageBeenComputed() const {
  return hasCachedLinkage();
}

/// Looks through UsingDecls and ObjCCompatibleAliasDecls for
/// the underlying named decl.
NamedDecl *getUnderlyingDecl() {
  // Fast-path the common case.
  if (this->getKind() != UsingShadow &&
      this->getKind() != ConstructorUsingShadow &&
      this->getKind() != ObjCCompatibleAlias &&
      this->getKind() != NamespaceAlias)
    return this;

  return getUnderlyingDeclImpl();
}
const NamedDecl *getUnderlyingDecl() const {
  return const_cast<NamedDecl*>(this)->getUnderlyingDecl();
}

NamedDecl *getMostRecentDecl() {
  return cast<NamedDecl>(static_cast<Decl *>(this)->getMostRecentDecl());
}
const NamedDecl *getMostRecentDecl() const {
  return const_cast<NamedDecl*>(this)->getMostRecentDecl();
}

ObjCStringFormatFamily getObjCFStringFormattingFamily() const;

static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K >= firstNamed && K <= lastNamed; }
484};

486inline raw_ostream &operator<<(raw_ostream &OS, const NamedDecl &ND) {
ND.printName(OS);
return OS;
489}

491/// Represents the declaration of a label.  Labels also have a
492/// corresponding LabelStmt, which indicates the position that the label was
493/// defined at.  For normal labels, the location of the decl is the same as the
494/// location of the statement.  For GNU local labels (__label__), the decl
495/// location is where the __label__ is.
496class LabelDecl : public NamedDecl {
LabelStmt *TheStmt;
StringRef MSAsmName;
bool MSAsmNameResolved = false;

/// For normal labels, this is the same as the main declaration
/// label, i.e., the location of the identifier; for GNU local labels,
/// this is the location of the __label__ keyword.
SourceLocation LocStart;

LabelDecl(DeclContext *DC, SourceLocation IdentL, IdentifierInfo *II,
          LabelStmt *S, SourceLocation StartL)
    : NamedDecl(Label, DC, IdentL, II), TheStmt(S), LocStart(StartL) {}

void anchor() override;

512public:
static LabelDecl *Create(ASTContext &C, DeclContext *DC,
                         SourceLocation IdentL, IdentifierInfo *II);
static LabelDecl *Create(ASTContext &C, DeclContext *DC,
                         SourceLocation IdentL, IdentifierInfo *II,
                         SourceLocation GnuLabelL);
static LabelDecl *CreateDeserialized(ASTContext &C, unsigned ID);

LabelStmt *getStmt() const { return TheStmt; }
void setStmt(LabelStmt *T) { TheStmt = T; }

bool isGnuLocal() const { return LocStart != getLocation(); }
void setLocStart(SourceLocation L) { LocStart = L; }

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__)) {
  return SourceRange(LocStart, getLocation());
}

bool isMSAsmLabel() const { return !MSAsmName.empty(); }
bool isResolvedMSAsmLabel() const { return isMSAsmLabel() && MSAsmNameResolved; }
void setMSAsmLabel(StringRef Name);
StringRef getMSAsmLabel() const { return MSAsmName; }
void setMSAsmLabelResolved() { MSAsmNameResolved = true; }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Label; }
539};

541/// Represent a C++ namespace.
542class NamespaceDecl : public NamedDecl, public DeclContext,
                    public Redeclarable<NamespaceDecl>
544{
/// The starting location of the source range, pointing
/// to either the namespace or the inline keyword.
SourceLocation LocStart;

/// The ending location of the source range.
SourceLocation RBraceLoc;

/// A pointer to either the anonymous namespace that lives just inside
/// this namespace or to the first namespace in the chain (the latter case
/// only when this is not the first in the chain), along with a
/// boolean value indicating whether this is an inline namespace.
llvm::PointerIntPair<NamespaceDecl *, 1, bool> AnonOrFirstNamespaceAndInline;

NamespaceDecl(ASTContext &C, DeclContext *DC, bool Inline,
              SourceLocation StartLoc, SourceLocation IdLoc,
              IdentifierInfo *Id, NamespaceDecl *PrevDecl);

using redeclarable_base = Redeclarable<NamespaceDecl>;

NamespaceDecl *getNextRedeclarationImpl() override;
NamespaceDecl *getPreviousDeclImpl() override;
NamespaceDecl *getMostRecentDeclImpl() override;

568public:
friend class ASTDeclReader;
friend class ASTDeclWriter;

static NamespaceDecl *Create(ASTContext &C, DeclContext *DC,
                             bool Inline, SourceLocation StartLoc,
                             SourceLocation IdLoc, IdentifierInfo *Id,
                             NamespaceDecl *PrevDecl);

static NamespaceDecl *CreateDeserialized(ASTContext &C, unsigned ID);

using redecl_range = redeclarable_base::redecl_range;
using redecl_iterator = redeclarable_base::redecl_iterator;

using redeclarable_base::redecls_begin;
using redeclarable_base::redecls_end;
using redeclarable_base::redecls;
using redeclarable_base::getPreviousDecl;
using redeclarable_base::getMostRecentDecl;
using redeclarable_base::isFirstDecl;

/// Returns true if this is an anonymous namespace declaration.
///
/// For example:
/// \code
///   namespace {
///     ...
///   };
/// \endcode
/// q.v. C++ [namespace.unnamed]
bool isAnonymousNamespace() const {
  return !getIdentifier();
}

/// Returns true if this is an inline namespace declaration.
bool isInline() const {
  return AnonOrFirstNamespaceAndInline.getInt();
}

/// Set whether this is an inline namespace declaration.
void setInline(bool Inline) {
  AnonOrFirstNamespaceAndInline.setInt(Inline);
}

/// Returns true if the inline qualifier for \c Name is redundant.
bool isRedundantInlineQualifierFor(DeclarationName Name) const {
  if (!isInline())
    return false;
  auto X = lookup(Name);
  auto Y = getParent()->lookup(Name);
  return std::distance(X.begin(), X.end()) ==
    std::distance(Y.begin(), Y.end());
}

/// Get the original (first) namespace declaration.
NamespaceDecl *getOriginalNamespace();

/// Get the original (first) namespace declaration.
const NamespaceDecl *getOriginalNamespace() const;

/// Return true if this declaration is an original (first) declaration
/// of the namespace. This is false for non-original (subsequent) namespace
/// declarations and anonymous namespaces.
bool isOriginalNamespace() const;

/// Retrieve the anonymous namespace nested inside this namespace,
/// if any.
NamespaceDecl *getAnonymousNamespace() const {
  return getOriginalNamespace()->AnonOrFirstNamespaceAndInline.getPointer();
}

void setAnonymousNamespace(NamespaceDecl *D) {
  getOriginalNamespace()->AnonOrFirstNamespaceAndInline.setPointer(D);
}

/// Retrieves the canonical declaration of this namespace.
NamespaceDecl *getCanonicalDecl() override {
  return getOriginalNamespace();
}
const NamespaceDecl *getCanonicalDecl() const {
  return getOriginalNamespace();
}

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__)) {
  return SourceRange(LocStart, RBraceLoc);
}

SourceLocation getBeginLoc() const LLVM_READONLY__attribute__((__pure__)) { return LocStart; }
SourceLocation getRBraceLoc() const { return RBraceLoc; }
void setLocStart(SourceLocation L) { LocStart = L; }
void setRBraceLoc(SourceLocation L) { RBraceLoc = L; }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Namespace; }
static DeclContext *castToDeclContext(const NamespaceDecl *D) {
  return static_cast<DeclContext *>(const_cast<NamespaceDecl*>(D));
}
static NamespaceDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<NamespaceDecl *>(const_cast<DeclContext*>(DC));
}
669};

671/// Represent the declaration of a variable (in which case it is
672/// an lvalue) a function (in which case it is a function designator) or
673/// an enum constant.
674class ValueDecl : public NamedDecl {
QualType DeclType;

void anchor() override;

679protected:
ValueDecl(Kind DK, DeclContext *DC, SourceLocation L,
          DeclarationName N, QualType T)
  : NamedDecl(DK, DC, L, N), DeclType(T) {}

684public:
QualType getType() const { return DeclType; }
void setType(QualType newType) { DeclType = newType; }

/// Determine whether this symbol is weakly-imported,
///        or declared with the weak or weak-ref attr.
bool isWeak() const;

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K >= firstValue && K <= lastValue; }
695};

697/// A struct with extended info about a syntactic
698/// name qualifier, to be used for the case of out-of-line declarations.
699struct QualifierInfo {
NestedNameSpecifierLoc QualifierLoc;

/// The number of "outer" template parameter lists.
/// The count includes all of the template parameter lists that were matched
/// against the template-ids occurring into the NNS and possibly (in the
/// case of an explicit specialization) a final "template <>".
unsigned NumTemplParamLists = 0;

/// A new-allocated array of size NumTemplParamLists,
/// containing pointers to the "outer" template parameter lists.
/// It includes all of the template parameter lists that were matched
/// against the template-ids occurring into the NNS and possibly (in the
/// case of an explicit specialization) a final "template <>".
TemplateParameterList** TemplParamLists = nullptr;

QualifierInfo() = default;
QualifierInfo(const QualifierInfo &) = delete;
QualifierInfo& operator=(const QualifierInfo &) = delete;

/// Sets info about "outer" template parameter lists.
void setTemplateParameterListsInfo(ASTContext &Context,
                                   ArrayRef<TemplateParameterList *> TPLists);
722};

724/// Represents a ValueDecl that came out of a declarator.
725/// Contains type source information through TypeSourceInfo.
726class DeclaratorDecl : public ValueDecl {
// A struct representing a TInfo, a trailing requires-clause and a syntactic
// qualifier, to be used for the (uncommon) case of out-of-line declarations
// and constrained function decls.
struct ExtInfo : public QualifierInfo {
  TypeSourceInfo *TInfo;
  Expr *TrailingRequiresClause = nullptr;
};

llvm::PointerUnion<TypeSourceInfo *, ExtInfo *> DeclInfo;

/// The start of the source range for this declaration,
/// ignoring outer template declarations.
SourceLocation InnerLocStart;

bool hasExtInfo() const { return DeclInfo.is<ExtInfo*>(); }
ExtInfo *getExtInfo() { return DeclInfo.get<ExtInfo*>(); }
const ExtInfo *getExtInfo() const { return DeclInfo.get<ExtInfo*>(); }

745protected:
DeclaratorDecl(Kind DK, DeclContext *DC, SourceLocation L,
               DeclarationName N, QualType T, TypeSourceInfo *TInfo,
               SourceLocation StartL)
    : ValueDecl(DK, DC, L, N, T), DeclInfo(TInfo), InnerLocStart(StartL) {}

751public:
friend class ASTDeclReader;
friend class ASTDeclWriter;

TypeSourceInfo *getTypeSourceInfo() const {
  return hasExtInfo()
    ? getExtInfo()->TInfo
    : DeclInfo.get<TypeSourceInfo*>();
}

void setTypeSourceInfo(TypeSourceInfo *TI) {
  if (hasExtInfo())
    getExtInfo()->TInfo = TI;
  else
    DeclInfo = TI;
}

/// Return start of source range ignoring outer template declarations.
SourceLocation getInnerLocStart() const { return InnerLocStart; }
void setInnerLocStart(SourceLocation L) { InnerLocStart = L; }

/// Return start of source range taking into account any outer template
/// declarations.
SourceLocation getOuterLocStart() const;

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

SourceLocation getBeginLoc() const LLVM_READONLY__attribute__((__pure__)) {
  return getOuterLocStart();
}

/// Retrieve the nested-name-specifier that qualifies the name of this
/// declaration, if it was present in the source.
NestedNameSpecifier *getQualifier() const {
  return hasExtInfo() ? getExtInfo()->QualifierLoc.getNestedNameSpecifier()
                      : nullptr;
}

/// Retrieve the nested-name-specifier (with source-location
/// information) that qualifies the name of this declaration, if it was
/// present in the source.
NestedNameSpecifierLoc getQualifierLoc() const {
  return hasExtInfo() ? getExtInfo()->QualifierLoc
                      : NestedNameSpecifierLoc();
}

void setQualifierInfo(NestedNameSpecifierLoc QualifierLoc);

/// \brief Get the constraint-expression introduced by the trailing
/// requires-clause in the function/member declaration, or null if no
/// requires-clause was provided.
Expr *getTrailingRequiresClause() {
  return hasExtInfo() ? getExtInfo()->TrailingRequiresClause
                      : nullptr;
}

const Expr *getTrailingRequiresClause() const {
  return hasExtInfo() ? getExtInfo()->TrailingRequiresClause
                      : nullptr;
}

void setTrailingRequiresClause(Expr *TrailingRequiresClause);

unsigned getNumTemplateParameterLists() const {
  return hasExtInfo() ? getExtInfo()->NumTemplParamLists : 0;
}

TemplateParameterList *getTemplateParameterList(unsigned index) const {
  assert(index < getNumTemplateParameterLists())((void)0);
  return getExtInfo()->TemplParamLists[index];
}

void setTemplateParameterListsInfo(ASTContext &Context,
                                   ArrayRef<TemplateParameterList *> TPLists);

SourceLocation getTypeSpecStartLoc() const;
SourceLocation getTypeSpecEndLoc() const;

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) {
  return K >= firstDeclarator && K <= lastDeclarator;
}
834};

836/// Structure used to store a statement, the constant value to
837/// which it was evaluated (if any), and whether or not the statement
838/// is an integral constant expression (if known).
839struct EvaluatedStmt {
/// Whether this statement was already evaluated.
bool WasEvaluated : 1;

/// Whether this statement is being evaluated.
bool IsEvaluating : 1;

/// Whether this variable is known to have constant initialization. This is
/// currently only computed in C++, for static / thread storage duration
/// variables that might have constant initialization and for variables that
/// are usable in constant expressions.
bool HasConstantInitialization : 1;

/// Whether this variable is known to have constant destruction. That is,
/// whether running the destructor on the initial value is a side-effect
/// (and doesn't inspect any state that might have changed during program
/// execution). This is currently only computed if the destructor is
/// non-trivial.
bool HasConstantDestruction : 1;

/// In C++98, whether the initializer is an ICE. This affects whether the
/// variable is usable in constant expressions.
bool HasICEInit : 1;
bool CheckedForICEInit : 1;

Stmt *Value;
APValue Evaluated;

EvaluatedStmt()
    : WasEvaluated(false), IsEvaluating(false),
      HasConstantInitialization(false), HasConstantDestruction(false),
      HasICEInit(false), CheckedForICEInit(false) {}
871};

873/// Represents a variable declaration or definition.
874class VarDecl : public DeclaratorDecl, public Redeclarable<VarDecl> {
875public:
/// Initialization styles.
enum InitializationStyle {
  /// C-style initialization with assignment
  CInit,

  /// Call-style initialization (C++98)
  CallInit,

  /// Direct list-initialization (C++11)
  ListInit
};

/// Kinds of thread-local storage.
enum TLSKind {
  /// Not a TLS variable.
  TLS_None,

  /// TLS with a known-constant initializer.
  TLS_Static,

  /// TLS with a dynamic initializer.
  TLS_Dynamic
};

/// Return the string used to specify the storage class \p SC.
///
/// It is illegal to call this function with SC == None.
static const char *getStorageClassSpecifierString(StorageClass SC);

905protected:
// A pointer union of Stmt * and EvaluatedStmt *. When an EvaluatedStmt, we
// have allocated the auxiliary struct of information there.
//
// TODO: It is a bit unfortunate to use a PointerUnion inside the VarDecl for
// this as *many* VarDecls are ParmVarDecls that don't have default
// arguments. We could save some space by moving this pointer union to be
// allocated in trailing space when necessary.
using InitType = llvm::PointerUnion<Stmt *, EvaluatedStmt *>;

/// The initializer for this variable or, for a ParmVarDecl, the
/// C++ default argument.
mutable InitType Init;

919private:
friend class ASTDeclReader;
friend class ASTNodeImporter;
friend class StmtIteratorBase;

class VarDeclBitfields {
  friend class ASTDeclReader;
  friend class VarDecl;

  unsigned SClass : 3;
  unsigned TSCSpec : 2;
  unsigned InitStyle : 2;

  /// Whether this variable is an ARC pseudo-__strong variable; see
  /// isARCPseudoStrong() for details.
  unsigned ARCPseudoStrong : 1;
};
enum { NumVarDeclBits = 8 };

938protected:
enum { NumParameterIndexBits = 8 };

enum DefaultArgKind {
  DAK_None,
  DAK_Unparsed,
  DAK_Uninstantiated,
  DAK_Normal
};

enum { NumScopeDepthOrObjCQualsBits = 7 };

class ParmVarDeclBitfields {
  friend class ASTDeclReader;
  friend class ParmVarDecl;

  unsigned : NumVarDeclBits;

  /// Whether this parameter inherits a default argument from a
  /// prior declaration.
  unsigned HasInheritedDefaultArg : 1;

  /// Describes the kind of default argument for this parameter. By default
  /// this is none. If this is normal, then the default argument is stored in
  /// the \c VarDecl initializer expression unless we were unable to parse
  /// (even an invalid) expression for the default argument.
  unsigned DefaultArgKind : 2;

  /// Whether this parameter undergoes K&R argument promotion.
  unsigned IsKNRPromoted : 1;

  /// Whether this parameter is an ObjC method parameter or not.
  unsigned IsObjCMethodParam : 1;

  /// If IsObjCMethodParam, a Decl::ObjCDeclQualifier.
  /// Otherwise, the number of function parameter scopes enclosing
  /// the function parameter scope in which this parameter was
  /// declared.
  unsigned ScopeDepthOrObjCQuals : NumScopeDepthOrObjCQualsBits;

  /// The number of parameters preceding this parameter in the
  /// function parameter scope in which it was declared.
  unsigned ParameterIndex : NumParameterIndexBits;
};

class NonParmVarDeclBitfields {
  friend class ASTDeclReader;
  friend class ImplicitParamDecl;
  friend class VarDecl;

  unsigned : NumVarDeclBits;

  // FIXME: We need something similar to CXXRecordDecl::DefinitionData.
  /// Whether this variable is a definition which was demoted due to
  /// module merge.
  unsigned IsThisDeclarationADemotedDefinition : 1;

  /// Whether this variable is the exception variable in a C++ catch
  /// or an Objective-C @catch statement.
  unsigned ExceptionVar : 1;

  /// Whether this local variable could be allocated in the return
  /// slot of its function, enabling the named return value optimization
  /// (NRVO).
  unsigned NRVOVariable : 1;

  /// Whether this variable is the for-range-declaration in a C++0x
  /// for-range statement.
  unsigned CXXForRangeDecl : 1;

  /// Whether this variable is the for-in loop declaration in Objective-C.
  unsigned ObjCForDecl : 1;

  /// Whether this variable is (C++1z) inline.
  unsigned IsInline : 1;

  /// Whether this variable has (C++1z) inline explicitly specified.
  unsigned IsInlineSpecified : 1;

  /// Whether this variable is (C++0x) constexpr.
  unsigned IsConstexpr : 1;

  /// Whether this variable is the implicit variable for a lambda
  /// init-capture.
  unsigned IsInitCapture : 1;

  /// Whether this local extern variable's previous declaration was
  /// declared in the same block scope. This controls whether we should merge
  /// the type of this declaration with its previous declaration.
  unsigned PreviousDeclInSameBlockScope : 1;

  /// Defines kind of the ImplicitParamDecl: 'this', 'self', 'vtt', '_cmd' or
  /// something else.
  unsigned ImplicitParamKind : 3;

  unsigned EscapingByref : 1;
};

union {
  unsigned AllBits;
  VarDeclBitfields VarDeclBits;
  ParmVarDeclBitfields ParmVarDeclBits;
  NonParmVarDeclBitfields NonParmVarDeclBits;
};

VarDecl(Kind DK, ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
        SourceLocation IdLoc, IdentifierInfo *Id, QualType T,
        TypeSourceInfo *TInfo, StorageClass SC);

using redeclarable_base = Redeclarable<VarDecl>;

VarDecl *getNextRedeclarationImpl() override {
  return getNextRedeclaration();
}

VarDecl *getPreviousDeclImpl() override {
  return getPreviousDecl();
}

VarDecl *getMostRecentDeclImpl() override {
  return getMostRecentDecl();
}

1061public:
using redecl_range = redeclarable_base::redecl_range;
using redecl_iterator = redeclarable_base::redecl_iterator;

using redeclarable_base::redecls_begin;
using redeclarable_base::redecls_end;
using redeclarable_base::redecls;
using redeclarable_base::getPreviousDecl;
using redeclarable_base::getMostRecentDecl;
using redeclarable_base::isFirstDecl;

static VarDecl *Create(ASTContext &C, DeclContext *DC,
                       SourceLocation StartLoc, SourceLocation IdLoc,
                       IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
                       StorageClass S);

static VarDecl *CreateDeserialized(ASTContext &C, unsigned ID);

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

/// Returns the storage class as written in the source. For the
/// computed linkage of symbol, see getLinkage.
StorageClass getStorageClass() const {
  return (StorageClass) VarDeclBits.SClass;
}
void setStorageClass(StorageClass SC);

void setTSCSpec(ThreadStorageClassSpecifier TSC) {
  VarDeclBits.TSCSpec = TSC;
  assert(VarDeclBits.TSCSpec == TSC && "truncation")((void)0);
}
ThreadStorageClassSpecifier getTSCSpec() const {
  return static_cast<ThreadStorageClassSpecifier>(VarDeclBits.TSCSpec);
}
TLSKind getTLSKind() const;

/// Returns true if a variable with function scope is a non-static local
/// variable.
bool hasLocalStorage() const {
  if (getStorageClass() == SC_None) {
    // OpenCL v1.2 s6.5.3: The __constant or constant address space name is
    // used to describe variables allocated in global memory and which are
    // accessed inside a kernel(s) as read-only variables. As such, variables
    // in constant address space cannot have local storage.
    if (getType().getAddressSpace() == LangAS::opencl_constant)
      return false;
    // Second check is for C++11 [dcl.stc]p4.
    return !isFileVarDecl() && getTSCSpec() == TSCS_unspecified;
  }

  // Global Named Register (GNU extension)
  if (getStorageClass() == SC_Register && !isLocalVarDeclOrParm())
    return false;

  // Return true for:  Auto, Register.
  // Return false for: Extern, Static, PrivateExtern, OpenCLWorkGroupLocal.

  return getStorageClass() >= SC_Auto;
}

/// Returns true if a variable with function scope is a static local
/// variable.
bool isStaticLocal() const {
  return (getStorageClass() == SC_Static ||
          // C++11 [dcl.stc]p4
          (getStorageClass() == SC_None && getTSCSpec() == TSCS_thread_local))
    && !isFileVarDecl();
}

/// Returns true if a variable has extern or __private_extern__
/// storage.
bool hasExternalStorage() const {
  return getStorageClass() == SC_Extern ||
         getStorageClass() == SC_PrivateExtern;
}

/// Returns true for all variables that do not have local storage.
///
/// This includes all global variables as well as static variables declared
/// within a function.
bool hasGlobalStorage() const { return !hasLocalStorage(); }

/// Get the storage duration of this variable, per C++ [basic.stc].
StorageDuration getStorageDuration() const {
  return hasLocalStorage() ? SD_Automatic :
         getTSCSpec() ? SD_Thread : SD_Static;
}

/// Compute the language linkage.
LanguageLinkage getLanguageLinkage() const;

/// Determines whether this variable is a variable with external, C linkage.
bool isExternC() const;

/// Determines whether this variable's context is, or is nested within,
/// a C++ extern "C" linkage spec.
bool isInExternCContext() const;

/// Determines whether this variable's context is, or is nested within,
/// a C++ extern "C++" linkage spec.
bool isInExternCXXContext() const;

/// Returns true for local variable declarations other than parameters.
/// Note that this includes static variables inside of functions. It also
/// includes variables inside blocks.
///
///   void foo() { int x; static int y; extern int z; }
bool isLocalVarDecl() const {
  if (getKind() != Decl::Var && getKind() != Decl::Decomposition)
    return false;
  if (const DeclContext *DC = getLexicalDeclContext())
    return DC->getRedeclContext()->isFunctionOrMethod();
  return false;
}

/// Similar to isLocalVarDecl but also includes parameters.
bool isLocalVarDeclOrParm() const {
  return isLocalVarDecl() || getKind() == Decl::ParmVar;
}

/// Similar to isLocalVarDecl, but excludes variables declared in blocks.
bool isFunctionOrMethodVarDecl() const {
  if (getKind() != Decl::Var && getKind() != Decl::Decomposition)
    return false;
  const DeclContext *DC = getLexicalDeclContext()->getRedeclContext();
  return DC->isFunctionOrMethod() && DC->getDeclKind() != Decl::Block;
}

/// Determines whether this is a static data member.
///
/// This will only be true in C++, and applies to, e.g., the
/// variable 'x' in:
/// \code
/// struct S {
///   static int x;
/// };
/// \endcode
bool isStaticDataMember() const {
  // If it wasn't static, it would be a FieldDecl.
  return getKind() != Decl::ParmVar && getDeclContext()->isRecord();
}

VarDecl *getCanonicalDecl() override;
const VarDecl *getCanonicalDecl() const {
  return const_cast<VarDecl*>(this)->getCanonicalDecl();
}

enum DefinitionKind {
  /// This declaration is only a declaration.
  DeclarationOnly,

  /// This declaration is a tentative definition.
  TentativeDefinition,

  /// This declaration is definitely a definition.
  Definition
};

/// Check whether this declaration is a definition. If this could be
/// a tentative definition (in C), don't check whether there's an overriding
/// definition.
DefinitionKind isThisDeclarationADefinition(ASTContext &) const;
DefinitionKind isThisDeclarationADefinition() const {
  return isThisDeclarationADefinition(getASTContext());
}

/// Check whether this variable is defined in this translation unit.
DefinitionKind hasDefinition(ASTContext &) const;
DefinitionKind hasDefinition() const {
  return hasDefinition(getASTContext());
}

/// Get the tentative definition that acts as the real definition in a TU.
/// Returns null if there is a proper definition available.
VarDecl *getActingDefinition();
const VarDecl *getActingDefinition() const {
  return const_cast<VarDecl*>(this)->getActingDefinition();
}

/// Get the real (not just tentative) definition for this declaration.
VarDecl *getDefinition(ASTContext &);
const VarDecl *getDefinition(ASTContext &C) const {
  return const_cast<VarDecl*>(this)->getDefinition(C);
}
VarDecl *getDefinition() {
  return getDefinition(getASTContext());
}
const VarDecl *getDefinition() const {
  return const_cast<VarDecl*>(this)->getDefinition();
}

/// Determine whether this is or was instantiated from an out-of-line
/// definition of a static data member.
bool isOutOfLine() const override;

/// Returns true for file scoped variable declaration.
bool isFileVarDecl() const {
  Kind K = getKind();
  if (K == ParmVar || K == ImplicitParam)
    return false;

  if (getLexicalDeclContext()->getRedeclContext()->isFileContext())
    return true;

  if (isStaticDataMember())
    return true;

  return false;
}

/// Get the initializer for this variable, no matter which
/// declaration it is attached to.
const Expr *getAnyInitializer() const {
  const VarDecl *D;
  return getAnyInitializer(D);
}

/// Get the initializer for this variable, no matter which
/// declaration it is attached to. Also get that declaration.
const Expr *getAnyInitializer(const VarDecl *&D) const;

bool hasInit() const;
const Expr *getInit() const {
  return const_cast<VarDecl *>(this)->getInit();
}
Expr *getInit();

/// Retrieve the address of the initializer expression.
Stmt **getInitAddress();

void setInit(Expr *I);

/// Get the initializing declaration of this variable, if any. This is
/// usually the definition, except that for a static data member it can be
/// the in-class declaration.
VarDecl *getInitializingDeclaration();
const VarDecl *getInitializingDeclaration() const {
  return const_cast<VarDecl *>(this)->getInitializingDeclaration();
}

/// Determine whether this variable's value might be usable in a
/// constant expression, according to the relevant language standard.
/// This only checks properties of the declaration, and does not check
/// whether the initializer is in fact a constant expression.
///
/// This corresponds to C++20 [expr.const]p3's notion of a
/// "potentially-constant" variable.
bool mightBeUsableInConstantExpressions(const ASTContext &C) const;

/// Determine whether this variable's value can be used in a
/// constant expression, according to the relevant language standard,
/// including checking whether it was initialized by a constant expression.
bool isUsableInConstantExpressions(const ASTContext &C) const;

EvaluatedStmt *ensureEvaluatedStmt() const;
EvaluatedStmt *getEvaluatedStmt() const;

/// Attempt to evaluate the value of the initializer attached to this
/// declaration, and produce notes explaining why it cannot be evaluated.
/// Returns a pointer to the value if evaluation succeeded, 0 otherwise.
APValue *evaluateValue() const;

1323private:
APValue *evaluateValueImpl(SmallVectorImpl<PartialDiagnosticAt> &Notes,
                           bool IsConstantInitialization) const;

1327public:
/// Return the already-evaluated value of this variable's
/// initializer, or NULL if the value is not yet known. Returns pointer
/// to untyped APValue if the value could not be evaluated.
APValue *getEvaluatedValue() const;

/// Evaluate the destruction of this variable to determine if it constitutes
/// constant destruction.
///
/// \pre hasConstantInitialization()
/// \return \c true if this variable has constant destruction, \c false if
///         not.
bool evaluateDestruction(SmallVectorImpl<PartialDiagnosticAt> &Notes) const;

/// Determine whether this variable has constant initialization.
///
/// This is only set in two cases: when the language semantics require
/// constant initialization (globals in C and some globals in C++), and when
/// the variable is usable in constant expressions (constexpr, const int, and
/// reference variables in C++).
bool hasConstantInitialization() const;

/// Determine whether the initializer of this variable is an integer constant
/// expression. For use in C++98, where this affects whether the variable is
/// usable in constant expressions.
bool hasICEInitializer(const ASTContext &Context) const;

/// Evaluate the initializer of this variable to determine whether it's a
/// constant initializer. Should only be called once, after completing the
/// definition of the variable.
bool checkForConstantInitialization(
    SmallVectorImpl<PartialDiagnosticAt> &Notes) const;

void setInitStyle(InitializationStyle Style) {
  VarDeclBits.InitStyle = Style;
}

/// The style of initialization for this declaration.
///
/// C-style initialization is "int x = 1;". Call-style initialization is
/// a C++98 direct-initializer, e.g. "int x(1);". The Init expression will be
/// the expression inside the parens or a "ClassType(a,b,c)" class constructor
/// expression for class types. List-style initialization is C++11 syntax,
/// e.g. "int x{1};". Clients can distinguish between different forms of
/// initialization by checking this value. In particular, "int x = {1};" is
/// C-style, "int x({1})" is call-style, and "int x{1};" is list-style; the
/// Init expression in all three cases is an InitListExpr.
InitializationStyle getInitStyle() const {
  return static_cast<InitializationStyle>(VarDeclBits.InitStyle);
}

/// Whether the initializer is a direct-initializer (list or call).
bool isDirectInit() const {
  return getInitStyle() != CInit;
}

/// If this definition should pretend to be a declaration.
bool isThisDeclarationADemotedDefinition() const {
  return isa<ParmVarDecl>(this) ? false :
    NonParmVarDeclBits.IsThisDeclarationADemotedDefinition;
}

/// This is a definition which should be demoted to a declaration.
///
/// In some cases (mostly module merging) we can end up with two visible
/// definitions one of which needs to be demoted to a declaration to keep
/// the AST invariants.
void demoteThisDefinitionToDeclaration() {
  assert(isThisDeclarationADefinition() && "Not a definition!")((void)0);
  assert(!isa<ParmVarDecl>(this) && "Cannot demote ParmVarDecls!")((void)0);
  NonParmVarDeclBits.IsThisDeclarationADemotedDefinition = 1;
}

/// Determine whether this variable is the exception variable in a
/// C++ catch statememt or an Objective-C \@catch statement.
bool isExceptionVariable() const {
  return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.ExceptionVar;
}
void setExceptionVariable(bool EV) {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.ExceptionVar = EV;
}

/// Determine whether this local variable can be used with the named
/// return value optimization (NRVO).
///
/// The named return value optimization (NRVO) works by marking certain
/// non-volatile local variables of class type as NRVO objects. These
/// locals can be allocated within the return slot of their containing
/// function, in which case there is no need to copy the object to the
/// return slot when returning from the function. Within the function body,
/// each return that returns the NRVO object will have this variable as its
/// NRVO candidate.
bool isNRVOVariable() const {
  return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.NRVOVariable;
}
void setNRVOVariable(bool NRVO) {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.NRVOVariable = NRVO;
}

/// Determine whether this variable is the for-range-declaration in
/// a C++0x for-range statement.
bool isCXXForRangeDecl() const {
  return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.CXXForRangeDecl;
}
void setCXXForRangeDecl(bool FRD) {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.CXXForRangeDecl = FRD;
}

/// Determine whether this variable is a for-loop declaration for a
/// for-in statement in Objective-C.
bool isObjCForDecl() const {
  return NonParmVarDeclBits.ObjCForDecl;
}

void setObjCForDecl(bool FRD) {
  NonParmVarDeclBits.ObjCForDecl = FRD;
}

/// Determine whether this variable is an ARC pseudo-__strong variable. A
/// pseudo-__strong variable has a __strong-qualified type but does not
/// actually retain the object written into it. Generally such variables are
/// also 'const' for safety. There are 3 cases where this will be set, 1) if
/// the variable is annotated with the objc_externally_retained attribute, 2)
/// if its 'self' in a non-init method, or 3) if its the variable in an for-in
/// loop.
bool isARCPseudoStrong() const { return VarDeclBits.ARCPseudoStrong; }
void setARCPseudoStrong(bool PS) { VarDeclBits.ARCPseudoStrong = PS; }

/// Whether this variable is (C++1z) inline.
bool isInline() const {
  return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.IsInline;
}
bool isInlineSpecified() const {
  return isa<ParmVarDecl>(this) ? false
                                : NonParmVarDeclBits.IsInlineSpecified;
}
void setInlineSpecified() {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.IsInline = true;
  NonParmVarDeclBits.IsInlineSpecified = true;
}
void setImplicitlyInline() {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.IsInline = true;
}

/// Whether this variable is (C++11) constexpr.
bool isConstexpr() const {
  return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.IsConstexpr;
}
void setConstexpr(bool IC) {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.IsConstexpr = IC;
}

/// Whether this variable is the implicit variable for a lambda init-capture.
bool isInitCapture() const {
  return isa<ParmVarDecl>(this) ? false : NonParmVarDeclBits.IsInitCapture;
}
void setInitCapture(bool IC) {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.IsInitCapture = IC;
}

/// Determine whether this variable is actually a function parameter pack or
/// init-capture pack.
bool isParameterPack() const;

/// Whether this local extern variable declaration's previous declaration
/// was declared in the same block scope. Only correct in C++.
bool isPreviousDeclInSameBlockScope() const {
  return isa<ParmVarDecl>(this)
             ? false
             : NonParmVarDeclBits.PreviousDeclInSameBlockScope;
}
void setPreviousDeclInSameBlockScope(bool Same) {
  assert(!isa<ParmVarDecl>(this))((void)0);
  NonParmVarDeclBits.PreviousDeclInSameBlockScope = Same;
}

/// Indicates the capture is a __block variable that is captured by a block
/// that can potentially escape (a block for which BlockDecl::doesNotEscape
/// returns false).
bool isEscapingByref() const;

/// Indicates the capture is a __block variable that is never captured by an
/// escaping block.
bool isNonEscapingByref() const;

void setEscapingByref() {
  NonParmVarDeclBits.EscapingByref = true;
}

/// Determines if this variable's alignment is dependent.
bool hasDependentAlignment() const;

/// Retrieve the variable declaration from which this variable could
/// be instantiated, if it is an instantiation (rather than a non-template).
VarDecl *getTemplateInstantiationPattern() const;

/// If this variable is an instantiated static data member of a
/// class template specialization, returns the templated static data member
/// from which it was instantiated.
VarDecl *getInstantiatedFromStaticDataMember() const;

/// If this variable is an instantiation of a variable template or a
/// static data member of a class template, determine what kind of
/// template specialization or instantiation this is.
TemplateSpecializationKind getTemplateSpecializationKind() const;

/// Get the template specialization kind of this variable for the purposes of
/// template instantiation. This differs from getTemplateSpecializationKind()
/// for an instantiation of a class-scope explicit specialization.
TemplateSpecializationKind
getTemplateSpecializationKindForInstantiation() const;

/// If this variable is an instantiation of a variable template or a
/// static data member of a class template, determine its point of
/// instantiation.
SourceLocation getPointOfInstantiation() const;

/// If this variable is an instantiation of a static data member of a
/// class template specialization, retrieves the member specialization
/// information.
MemberSpecializationInfo *getMemberSpecializationInfo() const;

/// For a static data member that was instantiated from a static
/// data member of a class template, set the template specialiation kind.
void setTemplateSpecializationKind(TemplateSpecializationKind TSK,
                      SourceLocation PointOfInstantiation = SourceLocation());

/// Specify that this variable is an instantiation of the
/// static data member VD.
void setInstantiationOfStaticDataMember(VarDecl *VD,
                                        TemplateSpecializationKind TSK);

/// Retrieves the variable template that is described by this
/// variable declaration.
///
/// Every variable template is represented as a VarTemplateDecl and a
/// VarDecl. The former contains template properties (such as
/// the template parameter lists) while the latter contains the
/// actual description of the template's
/// contents. VarTemplateDecl::getTemplatedDecl() retrieves the
/// VarDecl that from a VarTemplateDecl, while
/// getDescribedVarTemplate() retrieves the VarTemplateDecl from
/// a VarDecl.
VarTemplateDecl *getDescribedVarTemplate() const;

void setDescribedVarTemplate(VarTemplateDecl *Template);

// Is this variable known to have a definition somewhere in the complete
// program? This may be true even if the declaration has internal linkage and
// has no definition within this source file.
bool isKnownToBeDefined() const;

/// Is destruction of this variable entirely suppressed? If so, the variable
/// need not have a usable destructor at all.
bool isNoDestroy(const ASTContext &) const;

/// Would the destruction of this variable have any effect, and if so, what
/// kind?
QualType::DestructionKind needsDestruction(const ASTContext &Ctx) const;

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K >= firstVar && K <= lastVar; }
1597};

1599class ImplicitParamDecl : public VarDecl {
void anchor() override;

1602public:
/// Defines the kind of the implicit parameter: is this an implicit parameter
/// with pointer to 'this', 'self', '_cmd', virtual table pointers, captured
/// context or something else.
enum ImplicitParamKind : unsigned {
  /// Parameter for Objective-C 'self' argument
  ObjCSelf,

  /// Parameter for Objective-C '_cmd' argument
  ObjCCmd,

  /// Parameter for C++ 'this' argument
  CXXThis,

  /// Parameter for C++ virtual table pointers
  CXXVTT,

  /// Parameter for captured context
  CapturedContext,

  /// Other implicit parameter
  Other,
};

/// Create implicit parameter.
static ImplicitParamDecl *Create(ASTContext &C, DeclContext *DC,
                                 SourceLocation IdLoc, IdentifierInfo *Id,
                                 QualType T, ImplicitParamKind ParamKind);
static ImplicitParamDecl *Create(ASTContext &C, QualType T,
                                 ImplicitParamKind ParamKind);

static ImplicitParamDecl *CreateDeserialized(ASTContext &C, unsigned ID);

ImplicitParamDecl(ASTContext &C, DeclContext *DC, SourceLocation IdLoc,
                  IdentifierInfo *Id, QualType Type,
                  ImplicitParamKind ParamKind)
    : VarDecl(ImplicitParam, C, DC, IdLoc, IdLoc, Id, Type,
              /*TInfo=*/nullptr, SC_None) {
  NonParmVarDeclBits.ImplicitParamKind = ParamKind;
  setImplicit();
}

ImplicitParamDecl(ASTContext &C, QualType Type, ImplicitParamKind ParamKind)
    : VarDecl(ImplicitParam, C, /*DC=*/nullptr, SourceLocation(),
              SourceLocation(), /*Id=*/nullptr, Type,
              /*TInfo=*/nullptr, SC_None) {
  NonParmVarDeclBits.ImplicitParamKind = ParamKind;
  setImplicit();
}

/// Returns the implicit parameter kind.
ImplicitParamKind getParameterKind() const {
  return static_cast<ImplicitParamKind>(NonParmVarDeclBits.ImplicitParamKind);
}

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == ImplicitParam; }
1660};

1662/// Represents a parameter to a function.
1663class ParmVarDecl : public VarDecl {
1664public:
enum { MaxFunctionScopeDepth = 255 };
enum { MaxFunctionScopeIndex = 255 };

1668protected:
ParmVarDecl(Kind DK, ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
            SourceLocation IdLoc, IdentifierInfo *Id, QualType T,
            TypeSourceInfo *TInfo, StorageClass S, Expr *DefArg)
    : VarDecl(DK, C, DC, StartLoc, IdLoc, Id, T, TInfo, S) {
  assert(ParmVarDeclBits.HasInheritedDefaultArg == false)((void)0);
  assert(ParmVarDeclBits.DefaultArgKind == DAK_None)((void)0);
  assert(ParmVarDeclBits.IsKNRPromoted == false)((void)0);
  assert(ParmVarDeclBits.IsObjCMethodParam == false)((void)0);
  setDefaultArg(DefArg);
}

1680public:
static ParmVarDecl *Create(ASTContext &C, DeclContext *DC,
                           SourceLocation StartLoc,
                           SourceLocation IdLoc, IdentifierInfo *Id,
                           QualType T, TypeSourceInfo *TInfo,
                           StorageClass S, Expr *DefArg);

static ParmVarDecl *CreateDeserialized(ASTContext &C, unsigned ID);

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

void setObjCMethodScopeInfo(unsigned parameterIndex) {
  ParmVarDeclBits.IsObjCMethodParam = true;
  setParameterIndex(parameterIndex);
}

void setScopeInfo(unsigned scopeDepth, unsigned parameterIndex) {
  assert(!ParmVarDeclBits.IsObjCMethodParam)((void)0);

  ParmVarDeclBits.ScopeDepthOrObjCQuals = scopeDepth;
  assert(ParmVarDeclBits.ScopeDepthOrObjCQuals == scopeDepth((void)0)
         && "truncation!")((void)0);

  setParameterIndex(parameterIndex);
}

bool isObjCMethodParameter() const {
  return ParmVarDeclBits.IsObjCMethodParam;
}

/// Determines whether this parameter is destroyed in the callee function.
bool isDestroyedInCallee() const;

unsigned getFunctionScopeDepth() const {
  if (ParmVarDeclBits.IsObjCMethodParam) return 0;
  return ParmVarDeclBits.ScopeDepthOrObjCQuals;
}

static constexpr unsigned getMaxFunctionScopeDepth() {
  return (1u << NumScopeDepthOrObjCQualsBits) - 1;
}

/// Returns the index of this parameter in its prototype or method scope.
unsigned getFunctionScopeIndex() const {
  return getParameterIndex();
}

ObjCDeclQualifier getObjCDeclQualifier() const {
  if (!ParmVarDeclBits.IsObjCMethodParam) return OBJC_TQ_None;
  return ObjCDeclQualifier(ParmVarDeclBits.ScopeDepthOrObjCQuals);
}
void setObjCDeclQualifier(ObjCDeclQualifier QTVal) {
  assert(ParmVarDeclBits.IsObjCMethodParam)((void)0);
  ParmVarDeclBits.ScopeDepthOrObjCQuals = QTVal;
}

/// True if the value passed to this parameter must undergo
/// K&R-style default argument promotion:
///
/// C99 6.5.2.2.
///   If the expression that denotes the called function has a type
///   that does not include a prototype, the integer promotions are
///   performed on each argument, and arguments that have type float
///   are promoted to double.
bool isKNRPromoted() const {
  return ParmVarDeclBits.IsKNRPromoted;
}
void setKNRPromoted(bool promoted) {
  ParmVarDeclBits.IsKNRPromoted = promoted;
}

Expr *getDefaultArg();
const Expr *getDefaultArg() const {
  return const_cast<ParmVarDecl *>(this)->getDefaultArg();
}

void setDefaultArg(Expr *defarg);

/// Retrieve the source range that covers the entire default
/// argument.
SourceRange getDefaultArgRange() const;
void setUninstantiatedDefaultArg(Expr *arg);
Expr *getUninstantiatedDefaultArg();
const Expr *getUninstantiatedDefaultArg() const {
  return const_cast<ParmVarDecl *>(this)->getUninstantiatedDefaultArg();
}

/// Determines whether this parameter has a default argument,
/// either parsed or not.
bool hasDefaultArg() const;

/// Determines whether this parameter has a default argument that has not
/// yet been parsed. This will occur during the processing of a C++ class
/// whose member functions have default arguments, e.g.,
/// @code
///   class X {
///   public:
///     void f(int x = 17); // x has an unparsed default argument now
///   }; // x has a regular default argument now
/// @endcode
bool hasUnparsedDefaultArg() const {
  return ParmVarDeclBits.DefaultArgKind == DAK_Unparsed;
}

bool hasUninstantiatedDefaultArg() const {
  return ParmVarDeclBits.DefaultArgKind == DAK_Uninstantiated;
}

/// Specify that this parameter has an unparsed default argument.
/// The argument will be replaced with a real default argument via
/// setDefaultArg when the class definition enclosing the function
/// declaration that owns this default argument is completed.
void setUnparsedDefaultArg() {
  ParmVarDeclBits.DefaultArgKind = DAK_Unparsed;
}

bool hasInheritedDefaultArg() const {
  return ParmVarDeclBits.HasInheritedDefaultArg;
}

void setHasInheritedDefaultArg(bool I = true) {
  ParmVarDeclBits.HasInheritedDefaultArg = I;
}

QualType getOriginalType() const;

/// Sets the function declaration that owns this
/// ParmVarDecl. Since ParmVarDecls are often created before the
/// FunctionDecls that own them, this routine is required to update
/// the DeclContext appropriately.
void setOwningFunction(DeclContext *FD) { setDeclContext(FD); }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == ParmVar; }

1816private:
enum { ParameterIndexSentinel = (1 << NumParameterIndexBits) - 1 };

void setParameterIndex(unsigned parameterIndex) {
  if (parameterIndex >= ParameterIndexSentinel) {
    setParameterIndexLarge(parameterIndex);
    return;
  }

  ParmVarDeclBits.ParameterIndex = parameterIndex;
  assert(ParmVarDeclBits.ParameterIndex == parameterIndex && "truncation!")((void)0);
}
unsigned getParameterIndex() const {
  unsigned d = ParmVarDeclBits.ParameterIndex;
  return d == ParameterIndexSentinel ? getParameterIndexLarge() : d;
}

void setParameterIndexLarge(unsigned parameterIndex);
unsigned getParameterIndexLarge() const;
1835};

1837enum class MultiVersionKind {
None,
Target,
CPUSpecific,
CPUDispatch
1842};

1844/// Represents a function declaration or definition.
1845///
1846/// Since a given function can be declared several times in a program,
1847/// there may be several FunctionDecls that correspond to that
1848/// function. Only one of those FunctionDecls will be found when
1849/// traversing the list of declarations in the context of the
1850/// FunctionDecl (e.g., the translation unit); this FunctionDecl
1851/// contains all of the information known about the function. Other,
1852/// previous declarations of the function are available via the
1853/// getPreviousDecl() chain.
1854class FunctionDecl : public DeclaratorDecl,
                   public DeclContext,
                   public Redeclarable<FunctionDecl> {
// This class stores some data in DeclContext::FunctionDeclBits
// to save some space. Use the provided accessors to access it.
1859public:
/// The kind of templated function a FunctionDecl can be.
enum TemplatedKind {
  // Not templated.
  TK_NonTemplate,
  // The pattern in a function template declaration.
  TK_FunctionTemplate,
  // A non-template function that is an instantiation or explicit
  // specialization of a member of a templated class.
  TK_MemberSpecialization,
  // An instantiation or explicit specialization of a function template.
  // Note: this might have been instantiated from a templated class if it
  // is a class-scope explicit specialization.
  TK_FunctionTemplateSpecialization,
  // A function template specialization that hasn't yet been resolved to a
  // particular specialized function template.
  TK_DependentFunctionTemplateSpecialization
};

/// Stashed information about a defaulted function definition whose body has
/// not yet been lazily generated.
class DefaultedFunctionInfo final
    : llvm::TrailingObjects<DefaultedFunctionInfo, DeclAccessPair> {
  friend TrailingObjects;
  unsigned NumLookups;

public:
  static DefaultedFunctionInfo *Create(ASTContext &Context,
                                       ArrayRef<DeclAccessPair> Lookups);
  /// Get the unqualified lookup results that should be used in this
  /// defaulted function definition.
  ArrayRef<DeclAccessPair> getUnqualifiedLookups() const {
    return {getTrailingObjects<DeclAccessPair>(), NumLookups};
  }
};

1895private:
/// A new[]'d array of pointers to VarDecls for the formal
/// parameters of this function.  This is null if a prototype or if there are
/// no formals.
ParmVarDecl **ParamInfo = nullptr;

/// The active member of this union is determined by
/// FunctionDeclBits.HasDefaultedFunctionInfo.
union {
  /// The body of the function.
  LazyDeclStmtPtr Body;
  /// Information about a future defaulted function definition.
  DefaultedFunctionInfo *DefaultedInfo;
};

unsigned ODRHash;

/// End part of this FunctionDecl's source range.
///
/// We could compute the full range in getSourceRange(). However, when we're
/// dealing with a function definition deserialized from a PCH/AST file,
/// we can only compute the full range once the function body has been
/// de-serialized, so it's far better to have the (sometimes-redundant)
/// EndRangeLoc.
SourceLocation EndRangeLoc;

/// The template or declaration that this declaration
/// describes or was instantiated from, respectively.
///
/// For non-templates, this value will be NULL. For function
/// declarations that describe a function template, this will be a
/// pointer to a FunctionTemplateDecl. For member functions
/// of class template specializations, this will be a MemberSpecializationInfo
/// pointer containing information about the specialization.
/// For function template specializations, this will be a
/// FunctionTemplateSpecializationInfo, which contains information about
/// the template being specialized and the template arguments involved in
/// that specialization.
llvm::PointerUnion<FunctionTemplateDecl *,
                   MemberSpecializationInfo *,
                   FunctionTemplateSpecializationInfo *,
                   DependentFunctionTemplateSpecializationInfo *>
  TemplateOrSpecialization;

/// Provides source/type location info for the declaration name embedded in
/// the DeclaratorDecl base class.
DeclarationNameLoc DNLoc;

/// Specify that this function declaration is actually a function
/// template specialization.
///
/// \param C the ASTContext.
///
/// \param Template the function template that this function template
/// specialization specializes.
///
/// \param TemplateArgs the template arguments that produced this
/// function template specialization from the template.
///
/// \param InsertPos If non-NULL, the position in the function template
/// specialization set where the function template specialization data will
/// be inserted.
///
/// \param TSK the kind of template specialization this is.
///
/// \param TemplateArgsAsWritten location info of template arguments.
///
/// \param PointOfInstantiation point at which the function template
/// specialization was first instantiated.
void setFunctionTemplateSpecialization(ASTContext &C,
                                       FunctionTemplateDecl *Template,
                                     const TemplateArgumentList *TemplateArgs,
                                       void *InsertPos,
                                       TemplateSpecializationKind TSK,
                        const TemplateArgumentListInfo *TemplateArgsAsWritten,
                                       SourceLocation PointOfInstantiation);

/// Specify that this record is an instantiation of the
/// member function FD.
void setInstantiationOfMemberFunction(ASTContext &C, FunctionDecl *FD,
                                      TemplateSpecializationKind TSK);

void setParams(ASTContext &C, ArrayRef<ParmVarDecl *> NewParamInfo);

// This is unfortunately needed because ASTDeclWriter::VisitFunctionDecl
// need to access this bit but we want to avoid making ASTDeclWriter
// a friend of FunctionDeclBitfields just for this.
bool isDeletedBit() const { return FunctionDeclBits.IsDeleted; }

/// Whether an ODRHash has been stored.
bool hasODRHash() const { return FunctionDeclBits.HasODRHash; }

/// State that an ODRHash has been stored.
void setHasODRHash(bool B = true) { FunctionDeclBits.HasODRHash = B; }

1990protected:
FunctionDecl(Kind DK, ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
             const DeclarationNameInfo &NameInfo, QualType T,
             TypeSourceInfo *TInfo, StorageClass S, bool isInlineSpecified,
             ConstexprSpecKind ConstexprKind,
             Expr *TrailingRequiresClause = nullptr);

using redeclarable_base = Redeclarable<FunctionDecl>;

FunctionDecl *getNextRedeclarationImpl() override {
  return getNextRedeclaration();
}

FunctionDecl *getPreviousDeclImpl() override {
  return getPreviousDecl();
}

FunctionDecl *getMostRecentDeclImpl() override {
  return getMostRecentDecl();
}

2011public:
friend class ASTDeclReader;
friend class ASTDeclWriter;

using redecl_range = redeclarable_base::redecl_range;
using redecl_iterator = redeclarable_base::redecl_iterator;

using redeclarable_base::redecls_begin;
using redeclarable_base::redecls_end;
using redeclarable_base::redecls;
using redeclarable_base::getPreviousDecl;
using redeclarable_base::getMostRecentDecl;
using redeclarable_base::isFirstDecl;

static FunctionDecl *
Create(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
       SourceLocation NLoc, DeclarationName N, QualType T,
       TypeSourceInfo *TInfo, StorageClass SC, bool isInlineSpecified = false,
       bool hasWrittenPrototype = true,
       ConstexprSpecKind ConstexprKind = ConstexprSpecKind::Unspecified,
       Expr *TrailingRequiresClause = nullptr) {
  DeclarationNameInfo NameInfo(N, NLoc);
  return FunctionDecl::Create(C, DC, StartLoc, NameInfo, T, TInfo, SC,
                              isInlineSpecified, hasWrittenPrototype,
                              ConstexprKind, TrailingRequiresClause);
}

static FunctionDecl *Create(ASTContext &C, DeclContext *DC,
                            SourceLocation StartLoc,
                            const DeclarationNameInfo &NameInfo, QualType T,
                            TypeSourceInfo *TInfo, StorageClass SC,
                            bool isInlineSpecified, bool hasWrittenPrototype,
                            ConstexprSpecKind ConstexprKind,
                            Expr *TrailingRequiresClause);

static FunctionDecl *CreateDeserialized(ASTContext &C, unsigned ID);

DeclarationNameInfo getNameInfo() const {
  return DeclarationNameInfo(getDeclName(), getLocation(), DNLoc);
}

void getNameForDiagnostic(raw_ostream &OS, const PrintingPolicy &Policy,
                          bool Qualified) const override;

void setRangeEnd(SourceLocation E) { EndRangeLoc = E; }

/// Returns the location of the ellipsis of a variadic function.
SourceLocation getEllipsisLoc() const {
  const auto *FPT = getType()->getAs<FunctionProtoType>();
  if (FPT && FPT->isVariadic())
    return FPT->getEllipsisLoc();
  return SourceLocation();
}

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

// Function definitions.
//
// A function declaration may be:
// - a non defining declaration,
// - a definition. A function may be defined because:
//   - it has a body, or will have it in the case of late parsing.
//   - it has an uninstantiated body. The body does not exist because the
//     function is not used yet, but the declaration is considered a
//     definition and does not allow other definition of this function.
//   - it does not have a user specified body, but it does not allow
//     redefinition, because it is deleted/defaulted or is defined through
//     some other mechanism (alias, ifunc).

/// Returns true if the function has a body.
///
/// The function body might be in any of the (re-)declarations of this
/// function. The variant that accepts a FunctionDecl pointer will set that
/// function declaration to the actual declaration containing the body (if
/// there is one).
bool hasBody(const FunctionDecl *&Definition) const;

bool hasBody() const override {
  const FunctionDecl* Definition;
  return hasBody(Definition);
}

/// Returns whether the function has a trivial body that does not require any
/// specific codegen.
bool hasTrivialBody() const;

/// Returns true if the function has a definition that does not need to be
/// instantiated.
///
/// The variant that accepts a FunctionDecl pointer will set that function
/// declaration to the declaration that is a definition (if there is one).
///
/// \param CheckForPendingFriendDefinition If \c true, also check for friend
///        declarations that were instantiataed from function definitions.
///        Such a declaration behaves as if it is a definition for the
///        purpose of redefinition checking, but isn't actually a "real"
///        definition until its body is instantiated.
bool isDefined(const FunctionDecl *&Definition,
               bool CheckForPendingFriendDefinition = false) const;

bool isDefined() const {
  const FunctionDecl* Definition;
  return isDefined(Definition);
}

/// Get the definition for this declaration.
FunctionDecl *getDefinition() {
  const FunctionDecl *Definition;
  if (isDefined(Definition))
    return const_cast<FunctionDecl *>(Definition);
  return nullptr;
}
const FunctionDecl *getDefinition() const {
  return const_cast<FunctionDecl *>(this)->getDefinition();
}

/// Retrieve the body (definition) of the function. The function body might be
/// in any of the (re-)declarations of this function. The variant that accepts
/// a FunctionDecl pointer will set that function declaration to the actual
/// declaration containing the body (if there is one).
/// NOTE: For checking if there is a body, use hasBody() instead, to avoid
/// unnecessary AST de-serialization of the body.
Stmt *getBody(const FunctionDecl *&Definition) const;

Stmt *getBody() const override {
  const FunctionDecl* Definition;
  return getBody(Definition);
}

/// Returns whether this specific declaration of the function is also a
/// definition that does not contain uninstantiated body.
///
/// This does not determine whether the function has been defined (e.g., in a
/// previous definition); for that information, use isDefined.
///
/// Note: the function declaration does not become a definition until the
/// parser reaches the definition, if called before, this function will return
/// `false`.
bool isThisDeclarationADefinition() const {
  return isDeletedAsWritten() || isDefaulted() ||
         doesThisDeclarationHaveABody() || hasSkippedBody() ||
         willHaveBody() || hasDefiningAttr();
}

/// Determine whether this specific declaration of the function is a friend
/// declaration that was instantiated from a function definition. Such
/// declarations behave like definitions in some contexts.
bool isThisDeclarationInstantiatedFromAFriendDefinition() const;

/// Returns whether this specific declaration of the function has a body.
bool doesThisDeclarationHaveABody() const {
  return (!FunctionDeclBits.HasDefaultedFunctionInfo && Body) ||
         isLateTemplateParsed();
}

void setBody(Stmt *B);
void setLazyBody(uint64_t Offset) {
  FunctionDeclBits.HasDefaultedFunctionInfo = false;
  Body = LazyDeclStmtPtr(Offset);
}

void setDefaultedFunctionInfo(DefaultedFunctionInfo *Info);
DefaultedFunctionInfo *getDefaultedFunctionInfo() const;

/// Whether this function is variadic.
bool isVariadic() const;

/// Whether this function is marked as virtual explicitly.
bool isVirtualAsWritten() const {
  return FunctionDeclBits.IsVirtualAsWritten;
}

/// State that this function is marked as virtual explicitly.
void setVirtualAsWritten(bool V) { FunctionDeclBits.IsVirtualAsWritten = V; }

/// Whether this virtual function is pure, i.e. makes the containing class
/// abstract.
bool isPure() const { return FunctionDeclBits.IsPure; }
void setPure(bool P = true);

/// Whether this templated function will be late parsed.
bool isLateTemplateParsed() const {
  return FunctionDeclBits.IsLateTemplateParsed;
}

/// State that this templated function will be late parsed.
void setLateTemplateParsed(bool ILT = true) {
  FunctionDeclBits.IsLateTemplateParsed = ILT;
}

/// Whether this function is "trivial" in some specialized C++ senses.
/// Can only be true for default constructors, copy constructors,
/// copy assignment operators, and destructors.  Not meaningful until
/// the class has been fully built by Sema.
bool isTrivial() const { return FunctionDeclBits.IsTrivial; }
void setTrivial(bool IT) { FunctionDeclBits.IsTrivial = IT; }

bool isTrivialForCall() const { return FunctionDeclBits.IsTrivialForCall; }
void setTrivialForCall(bool IT) { FunctionDeclBits.IsTrivialForCall = IT; }

/// Whether this function is defaulted. Valid for e.g.
/// special member functions, defaulted comparisions (not methods!).
bool isDefaulted() const { return FunctionDeclBits.IsDefaulted; }
void setDefaulted(bool D = true) { FunctionDeclBits.IsDefaulted = D; }

/// Whether this function is explicitly defaulted.
bool isExplicitlyDefaulted() const {
  return FunctionDeclBits.IsExplicitlyDefaulted;
}

/// State that this function is explicitly defaulted.
void setExplicitlyDefaulted(bool ED = true) {
  FunctionDeclBits.IsExplicitlyDefaulted = ED;
}

/// True if this method is user-declared and was not
/// deleted or defaulted on its first declaration.
bool isUserProvided() const {
  auto *DeclAsWritten = this;
  if (FunctionDecl *Pattern = getTemplateInstantiationPattern())
    DeclAsWritten = Pattern;
  return !(DeclAsWritten->isDeleted() ||
           DeclAsWritten->getCanonicalDecl()->isDefaulted());
}

/// Whether falling off this function implicitly returns null/zero.
/// If a more specific implicit return value is required, front-ends
/// should synthesize the appropriate return statements.
bool hasImplicitReturnZero() const {
  return FunctionDeclBits.HasImplicitReturnZero;
}

/// State that falling off this function implicitly returns null/zero.
/// If a more specific implicit return value is required, front-ends
/// should synthesize the appropriate return statements.
void setHasImplicitReturnZero(bool IRZ) {
  FunctionDeclBits.HasImplicitReturnZero = IRZ;
}

/// Whether this function has a prototype, either because one
/// was explicitly written or because it was "inherited" by merging
/// a declaration without a prototype with a declaration that has a
/// prototype.
bool hasPrototype() const {
  return hasWrittenPrototype() || hasInheritedPrototype();
}

/// Whether this function has a written prototype.
bool hasWrittenPrototype() const {
  return FunctionDeclBits.HasWrittenPrototype;
}

/// State that this function has a written prototype.
void setHasWrittenPrototype(bool P = true) {
  FunctionDeclBits.HasWrittenPrototype = P;
}

/// Whether this function inherited its prototype from a
/// previous declaration.
bool hasInheritedPrototype() const {
  return FunctionDeclBits.HasInheritedPrototype;
}

/// State that this function inherited its prototype from a
/// previous declaration.
void setHasInheritedPrototype(bool P = true) {
  FunctionDeclBits.HasInheritedPrototype = P;
}

/// Whether this is a (C++11) constexpr function or constexpr constructor.
bool isConstexpr() const {
  return getConstexprKind() != ConstexprSpecKind::Unspecified;
}
void setConstexprKind(ConstexprSpecKind CSK) {
  FunctionDeclBits.ConstexprKind = static_cast<uint64_t>(CSK);
}
ConstexprSpecKind getConstexprKind() const {
  return static_cast<ConstexprSpecKind>(FunctionDeclBits.ConstexprKind);
}
bool isConstexprSpecified() const {
  return getConstexprKind() == ConstexprSpecKind::Constexpr;
}
bool isConsteval() const {
  return getConstexprKind() == ConstexprSpecKind::Consteval;
}

/// Whether the instantiation of this function is pending.
/// This bit is set when the decision to instantiate this function is made
/// and unset if and when the function body is created. That leaves out
/// cases where instantiation did not happen because the template definition
/// was not seen in this TU. This bit remains set in those cases, under the
/// assumption that the instantiation will happen in some other TU.
bool instantiationIsPending() const {
  return FunctionDeclBits.InstantiationIsPending;
}

/// State that the instantiation of this function is pending.
/// (see instantiationIsPending)
void setInstantiationIsPending(bool IC) {
  FunctionDeclBits.InstantiationIsPending = IC;
}

/// Indicates the function uses __try.
bool usesSEHTry() const { return FunctionDeclBits.UsesSEHTry; }
void setUsesSEHTry(bool UST) { FunctionDeclBits.UsesSEHTry = UST; }

/// Whether this function has been deleted.
///
/// A function that is "deleted" (via the C++0x "= delete" syntax)
/// acts like a normal function, except that it cannot actually be
/// called or have its address taken. Deleted functions are
/// typically used in C++ overload resolution to attract arguments
/// whose type or lvalue/rvalue-ness would permit the use of a
/// different overload that would behave incorrectly. For example,
/// one might use deleted functions to ban implicit conversion from
/// a floating-point number to an Integer type:
///
/// @code
/// struct Integer {
///   Integer(long); // construct from a long
///   Integer(double) = delete; // no construction from float or double
///   Integer(long double) = delete; // no construction from long double
/// };
/// @endcode
// If a function is deleted, its first declaration must be.
bool isDeleted() const {
  return getCanonicalDecl()->FunctionDeclBits.IsDeleted;
}

bool isDeletedAsWritten() const {
  return FunctionDeclBits.IsDeleted && !isDefaulted();
}

void setDeletedAsWritten(bool D = true) { FunctionDeclBits.IsDeleted = D; }

/// Determines whether this function is "main", which is the
/// entry point into an executable program.
bool isMain() const;

/// Determines whether this function is a MSVCRT user defined entry
/// point.
bool isMSVCRTEntryPoint() const;

/// Determines whether this operator new or delete is one
/// of the reserved global placement operators:
///    void *operator new(size_t, void *);
///    void *operator new[](size_t, void *);
///    void operator delete(void *, void *);
///    void operator delete[](void *, void *);
/// These functions have special behavior under [new.delete.placement]:
///    These functions are reserved, a C++ program may not define
///    functions that displace the versions in the Standard C++ library.
///    The provisions of [basic.stc.dynamic] do not apply to these
///    reserved placement forms of operator new and operator delete.
///
/// This function must be an allocation or deallocation function.
bool isReservedGlobalPlacementOperator() const;

/// Determines whether this function is one of the replaceable
/// global allocation functions:
///    void *operator new(size_t);
///    void *operator new(size_t, const std::nothrow_t &) noexcept;
///    void *operator new[](size_t);
///    void *operator new[](size_t, const std::nothrow_t &) noexcept;
///    void operator delete(void *) noexcept;
///    void operator delete(void *, std::size_t) noexcept;      [C++1y]
///    void operator delete(void *, const std::nothrow_t &) noexcept;
///    void operator delete[](void *) noexcept;
///    void operator delete[](void *, std::size_t) noexcept;    [C++1y]
///    void operator delete[](void *, const std::nothrow_t &) noexcept;
/// These functions have special behavior under C++1y [expr.new]:
///    An implementation is allowed to omit a call to a replaceable global
///    allocation function. [...]
///
/// If this function is an aligned allocation/deallocation function, return
/// the parameter number of the requested alignment through AlignmentParam.
///
/// If this function is an allocation/deallocation function that takes
/// the `std::nothrow_t` tag, return true through IsNothrow,
bool isReplaceableGlobalAllocationFunction(
    Optional<unsigned> *AlignmentParam = nullptr,
    bool *IsNothrow = nullptr) const;

/// Determine if this function provides an inline implementation of a builtin.
bool isInlineBuiltinDeclaration() const;

/// Determine whether this is a destroying operator delete.
bool isDestroyingOperatorDelete() const;

/// Compute the language linkage.
LanguageLinkage getLanguageLinkage() const;

/// Determines whether this function is a function with
/// external, C linkage.
bool isExternC() const;

/// Determines whether this function's context is, or is nested within,
/// a C++ extern "C" linkage spec.
bool isInExternCContext() const;

/// Determines whether this function's context is, or is nested within,
/// a C++ extern "C++" linkage spec.
bool isInExternCXXContext() const;

/// Determines whether this is a global function.
bool isGlobal() const;

/// Determines whether this function is known to be 'noreturn', through
/// an attribute on its declaration or its type.
bool isNoReturn() const;

/// True if the function was a definition but its body was skipped.
bool hasSkippedBody() const { return FunctionDeclBits.HasSkippedBody; }
void setHasSkippedBody(bool Skipped = true) {
  FunctionDeclBits.HasSkippedBody = Skipped;
}

/// True if this function will eventually have a body, once it's fully parsed.
bool willHaveBody() const { return FunctionDeclBits.WillHaveBody; }
void setWillHaveBody(bool V = true) { FunctionDeclBits.WillHaveBody = V; }

/// True if this function is considered a multiversioned function.
bool isMultiVersion() const {
  return getCanonicalDecl()->FunctionDeclBits.IsMultiVersion;
}

/// Sets the multiversion state for this declaration and all of its
/// redeclarations.
void setIsMultiVersion(bool V = true) {
  getCanonicalDecl()->FunctionDeclBits.IsMultiVersion = V;
}

/// Gets the kind of multiversioning attribute this declaration has. Note that
/// this can return a value even if the function is not multiversion, such as
/// the case of 'target'.
MultiVersionKind getMultiVersionKind() const;


/// True if this function is a multiversioned dispatch function as a part of
/// the cpu_specific/cpu_dispatch functionality.
bool isCPUDispatchMultiVersion() const;
/// True if this function is a multiversioned processor specific function as a
/// part of the cpu_specific/cpu_dispatch functionality.
bool isCPUSpecificMultiVersion() const;

/// True if this function is a multiversioned dispatch function as a part of
/// the target functionality.
bool isTargetMultiVersion() const;

/// \brief Get the associated-constraints of this function declaration.
/// Currently, this will either be a vector of size 1 containing the
/// trailing-requires-clause or an empty vector.
///
/// Use this instead of getTrailingRequiresClause for concepts APIs that
/// accept an ArrayRef of constraint expressions.
void getAssociatedConstraints(SmallVectorImpl<const Expr *> &AC) const {
  if (auto *TRC = getTrailingRequiresClause())
    AC.push_back(TRC);
}

void setPreviousDeclaration(FunctionDecl * PrevDecl);

FunctionDecl *getCanonicalDecl() override;
const FunctionDecl *getCanonicalDecl() const {
  return const_cast<FunctionDecl*>(this)->getCanonicalDecl();
}

unsigned getBuiltinID(bool ConsiderWrapperFunctions = false) const;

// ArrayRef interface to parameters.
ArrayRef<ParmVarDecl *> parameters() const {
  return {ParamInfo, getNumParams()};
}
MutableArrayRef<ParmVarDecl *> parameters() {
  return {ParamInfo, getNumParams()};
}

// Iterator access to formal parameters.
using param_iterator = MutableArrayRef<ParmVarDecl *>::iterator;
using param_const_iterator = ArrayRef<ParmVarDecl *>::const_iterator;

bool param_empty() const { return parameters().empty(); }
param_iterator param_begin() { return parameters().begin(); }
param_iterator param_end() { return parameters().end(); }
param_const_iterator param_begin() const { return parameters().begin(); }
param_const_iterator param_end() const { return parameters().end(); }
size_t param_size() const { return parameters().size(); }

/// Return the number of parameters this function must have based on its
/// FunctionType.  This is the length of the ParamInfo array after it has been
/// created.
unsigned getNumParams() const;

const ParmVarDecl *getParamDecl(unsigned i) const {
  assert(i < getNumParams() && "Illegal param #")((void)0);
  return ParamInfo[i];
}
ParmVarDecl *getParamDecl(unsigned i) {
  assert(i < getNumParams() && "Illegal param #")((void)0);
  return ParamInfo[i];
}
void setParams(ArrayRef<ParmVarDecl *> NewParamInfo) {
  setParams(getASTContext(), NewParamInfo);
}

/// Returns the minimum number of arguments needed to call this function. This
/// may be fewer than the number of function parameters, if some of the
/// parameters have default arguments (in C++).
unsigned getMinRequiredArguments() const;

/// Determine whether this function has a single parameter, or multiple
/// parameters where all but the first have default arguments.
///
/// This notion is used in the definition of copy/move constructors and
/// initializer list constructors. Note that, unlike getMinRequiredArguments,
/// parameter packs are not treated specially here.
bool hasOneParamOrDefaultArgs() const;

/// Find the source location information for how the type of this function
/// was written. May be absent (for example if the function was declared via
/// a typedef) and may contain a different type from that of the function
/// (for example if the function type was adjusted by an attribute).
FunctionTypeLoc getFunctionTypeLoc() const;

QualType getReturnType() const {
  return getType()->castAs<FunctionType>()->getReturnType();
}

/// Attempt to compute an informative source range covering the
/// function return type. This may omit qualifiers and other information with
/// limited representation in the AST.
SourceRange getReturnTypeSourceRange() const;

/// Attempt to compute an informative source range covering the
/// function parameters, including the ellipsis of a variadic function.
/// The source range excludes the parentheses, and is invalid if there are
/// no parameters and no ellipsis.
SourceRange getParametersSourceRange() const;

/// Get the declared return type, which may differ from the actual return
/// type if the return type is deduced.
QualType getDeclaredReturnType() const {
  auto *TSI = getTypeSourceInfo();
  QualType T = TSI ? TSI->getType() : getType();
  return T->castAs<FunctionType>()->getReturnType();
}

/// Gets the ExceptionSpecificationType as declared.
ExceptionSpecificationType getExceptionSpecType() const {
  auto *TSI = getTypeSourceInfo();
  QualType T = TSI ? TSI->getType() : getType();
  const auto *FPT = T->getAs<FunctionProtoType>();
  return FPT ? FPT->getExceptionSpecType() : EST_None;
}

/// Attempt to compute an informative source range covering the
/// function exception specification, if any.
SourceRange getExceptionSpecSourceRange() const;

/// Determine the type of an expression that calls this function.
QualType getCallResultType() const {
  return getType()->castAs<FunctionType>()->getCallResultType(
      getASTContext());
}

/// Returns the storage class as written in the source. For the
/// computed linkage of symbol, see getLinkage.
StorageClass getStorageClass() const {
  return static_cast<StorageClass>(FunctionDeclBits.SClass);
}

/// Sets the storage class as written in the source.
void setStorageClass(StorageClass SClass) {
  FunctionDeclBits.SClass = SClass;
}

/// Determine whether the "inline" keyword was specified for this
/// function.
bool isInlineSpecified() const { return FunctionDeclBits.IsInlineSpecified; }

/// Set whether the "inline" keyword was specified for this function.
void setInlineSpecified(bool I) {
  FunctionDeclBits.IsInlineSpecified = I;
  FunctionDeclBits.IsInline = I;
}

/// Flag that this function is implicitly inline.
void setImplicitlyInline(bool I = true) { FunctionDeclBits.IsInline = I; }

/// Determine whether this function should be inlined, because it is
/// either marked "inline" or "constexpr" or is a member function of a class
/// that was defined in the class body.
bool isInlined() const { return FunctionDeclBits.IsInline; }

bool isInlineDefinitionExternallyVisible() const;

bool isMSExternInline() const;

bool doesDeclarationForceExternallyVisibleDefinition() const;

bool isStatic() const { return getStorageClass() == SC_Static; }

/// Whether this function declaration represents an C++ overloaded
/// operator, e.g., "operator+".
bool isOverloadedOperator() const {
  return getOverloadedOperator() != OO_None;
}

OverloadedOperatorKind getOverloadedOperator() const;

const IdentifierInfo *getLiteralIdentifier() const;

/// If this function is an instantiation of a member function
/// of a class template specialization, retrieves the function from
/// which it was instantiated.
///
/// This routine will return non-NULL for (non-templated) member
/// functions of class templates and for instantiations of function
/// templates. For example, given:
///
/// \code
/// template<typename T>
/// struct X {
///   void f(T);
/// };
/// \endcode
///
/// The declaration for X<int>::f is a (non-templated) FunctionDecl
/// whose parent is the class template specialization X<int>. For
/// this declaration, getInstantiatedFromFunction() will return
/// the FunctionDecl X<T>::A. When a complete definition of
/// X<int>::A is required, it will be instantiated from the
/// declaration returned by getInstantiatedFromMemberFunction().
FunctionDecl *getInstantiatedFromMemberFunction() const;

/// What kind of templated function this is.
TemplatedKind getTemplatedKind() const;

/// If this function is an instantiation of a member function of a
/// class template specialization, retrieves the member specialization
/// information.
MemberSpecializationInfo *getMemberSpecializationInfo() const;

/// Specify that this record is an instantiation of the
/// member function FD.
void setInstantiationOfMemberFunction(FunctionDecl *FD,
                                      TemplateSpecializationKind TSK) {
  setInstantiationOfMemberFunction(getASTContext(), FD, TSK);
}

/// Retrieves the function template that is described by this
/// function declaration.
///
/// Every function template is represented as a FunctionTemplateDecl
/// and a FunctionDecl (or something derived from FunctionDecl). The
/// former contains template properties (such as the template
/// parameter lists) while the latter contains the actual
/// description of the template's
/// contents. FunctionTemplateDecl::getTemplatedDecl() retrieves the
/// FunctionDecl that describes the function template,
/// getDescribedFunctionTemplate() retrieves the
/// FunctionTemplateDecl from a FunctionDecl.
FunctionTemplateDecl *getDescribedFunctionTemplate() const;

void setDescribedFunctionTemplate(FunctionTemplateDecl *Template);

/// Determine whether this function is a function template
/// specialization.
bool isFunctionTemplateSpecialization() const {
  return getPrimaryTemplate() != nullptr;
}

/// If this function is actually a function template specialization,
/// retrieve information about this function template specialization.
/// Otherwise, returns NULL.
FunctionTemplateSpecializationInfo *getTemplateSpecializationInfo() const;

/// Determines whether this function is a function template
/// specialization or a member of a class template specialization that can
/// be implicitly instantiated.
bool isImplicitlyInstantiable() const;

/// Determines if the given function was instantiated from a
/// function template.
bool isTemplateInstantiation() const;

/// Retrieve the function declaration from which this function could
/// be instantiated, if it is an instantiation (rather than a non-template
/// or a specialization, for example).
///
/// If \p ForDefinition is \c false, explicit specializations will be treated
/// as if they were implicit instantiations. This will then find the pattern
/// corresponding to non-definition portions of the declaration, such as
/// default arguments and the exception specification.
FunctionDecl *
getTemplateInstantiationPattern(bool ForDefinition = true) const;

/// Retrieve the primary template that this function template
/// specialization either specializes or was instantiated from.
///
/// If this function declaration is not a function template specialization,
/// returns NULL.
FunctionTemplateDecl *getPrimaryTemplate() const;

/// Retrieve the template arguments used to produce this function
/// template specialization from the primary template.
///
/// If this function declaration is not a function template specialization,
/// returns NULL.
const TemplateArgumentList *getTemplateSpecializationArgs() const;

/// Retrieve the template argument list as written in the sources,
/// if any.
///
/// If this function declaration is not a function template specialization
/// or if it had no explicit template argument list, returns NULL.
/// Note that it an explicit template argument list may be written empty,
/// e.g., template<> void foo<>(char* s);
const ASTTemplateArgumentListInfo*
getTemplateSpecializationArgsAsWritten() const;

/// Specify that this function declaration is actually a function
/// template specialization.
///
/// \param Template the function template that this function template
/// specialization specializes.
///
/// \param TemplateArgs the template arguments that produced this
/// function template specialization from the template.
///
/// \param InsertPos If non-NULL, the position in the function template
/// specialization set where the function template specialization data will
/// be inserted.
///
/// \param TSK the kind of template specialization this is.
///
/// \param TemplateArgsAsWritten location info of template arguments.
///
/// \param PointOfInstantiation point at which the function template
/// specialization was first instantiated.
void setFunctionTemplateSpecialization(FunctionTemplateDecl *Template,
              const TemplateArgumentList *TemplateArgs,
              void *InsertPos,
              TemplateSpecializationKind TSK = TSK_ImplicitInstantiation,
              const TemplateArgumentListInfo *TemplateArgsAsWritten = nullptr,
              SourceLocation PointOfInstantiation = SourceLocation()) {
  setFunctionTemplateSpecialization(getASTContext(), Template, TemplateArgs,
                                    InsertPos, TSK, TemplateArgsAsWritten,
                                    PointOfInstantiation);
}

/// Specifies that this function declaration is actually a
/// dependent function template specialization.
void setDependentTemplateSpecialization(ASTContext &Context,
                           const UnresolvedSetImpl &Templates,
                    const TemplateArgumentListInfo &TemplateArgs);

DependentFunctionTemplateSpecializationInfo *
getDependentSpecializationInfo() const;

/// Determine what kind of template instantiation this function
/// represents.
TemplateSpecializationKind getTemplateSpecializationKind() const;

/// Determine the kind of template specialization this function represents
/// for the purpose of template instantiation.
TemplateSpecializationKind
getTemplateSpecializationKindForInstantiation() const;

/// Determine what kind of template instantiation this function
/// represents.
void setTemplateSpecializationKind(TemplateSpecializationKind TSK,
                      SourceLocation PointOfInstantiation = SourceLocation());

/// Retrieve the (first) point of instantiation of a function template
/// specialization or a member of a class template specialization.
///
/// \returns the first point of instantiation, if this function was
/// instantiated from a template; otherwise, returns an invalid source
/// location.
SourceLocation getPointOfInstantiation() const;

/// Determine whether this is or was instantiated from an out-of-line
/// definition of a member function.
bool isOutOfLine() const override;

/// Identify a memory copying or setting function.
/// If the given function is a memory copy or setting function, returns
/// the corresponding Builtin ID. If the function is not a memory function,
/// returns 0.
unsigned getMemoryFunctionKind() const;

/// Returns ODRHash of the function.  This value is calculated and
/// stored on first call, then the stored value returned on the other calls.
unsigned getODRHash();

/// Returns cached ODRHash of the function.  This must have been previously
/// computed and stored.
unsigned getODRHash() const;

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) {
  return K >= firstFunction && K <= lastFunction;
}
static DeclContext *castToDeclContext(const FunctionDecl *D) {
  return static_cast<DeclContext *>(const_cast<FunctionDecl*>(D));
}
static FunctionDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<FunctionDecl *>(const_cast<DeclContext*>(DC));
}
2822};

2824/// Represents a member of a struct/union/class.
2825class FieldDecl : public DeclaratorDecl, public Mergeable<FieldDecl> {
unsigned BitField : 1;
unsigned Mutable : 1;
mutable unsigned CachedFieldIndex : 30;

/// The kinds of value we can store in InitializerOrBitWidth.
///
/// Note that this is compatible with InClassInitStyle except for
/// ISK_CapturedVLAType.
enum InitStorageKind {
  /// If the pointer is null, there's nothing special.  Otherwise,
  /// this is a bitfield and the pointer is the Expr* storing the
  /// bit-width.
  ISK_NoInit = (unsigned) ICIS_NoInit,

  /// The pointer is an (optional due to delayed parsing) Expr*
  /// holding the copy-initializer.
  ISK_InClassCopyInit = (unsigned) ICIS_CopyInit,

  /// The pointer is an (optional due to delayed parsing) Expr*
  /// holding the list-initializer.
  ISK_InClassListInit = (unsigned) ICIS_ListInit,

  /// The pointer is a VariableArrayType* that's been captured;
  /// the enclosing context is a lambda or captured statement.
  ISK_CapturedVLAType,
};

/// If this is a bitfield with a default member initializer, this
/// structure is used to represent the two expressions.
struct InitAndBitWidth {
  Expr *Init;
  Expr *BitWidth;
};

/// Storage for either the bit-width, the in-class initializer, or
/// both (via InitAndBitWidth), or the captured variable length array bound.
///
/// If the storage kind is ISK_InClassCopyInit or
/// ISK_InClassListInit, but the initializer is null, then this
/// field has an in-class initializer that has not yet been parsed
/// and attached.
// FIXME: Tail-allocate this to reduce the size of FieldDecl in the
// overwhelmingly common case that we have none of these things.
llvm::PointerIntPair<void *, 2, InitStorageKind> InitStorage;

2871protected:
FieldDecl(Kind DK, DeclContext *DC, SourceLocation StartLoc,
          SourceLocation IdLoc, IdentifierInfo *Id,
          QualType T, TypeSourceInfo *TInfo, Expr *BW, bool Mutable,
          InClassInitStyle InitStyle)
  : DeclaratorDecl(DK, DC, IdLoc, Id, T, TInfo, StartLoc),
    BitField(false), Mutable(Mutable), CachedFieldIndex(0),
    InitStorage(nullptr, (InitStorageKind) InitStyle) {
  if (BW)
    setBitWidth(BW);
}

2883public:
friend class ASTDeclReader;
friend class ASTDeclWriter;

static FieldDecl *Create(const ASTContext &C, DeclContext *DC,
                         SourceLocation StartLoc, SourceLocation IdLoc,
                         IdentifierInfo *Id, QualType T,
                         TypeSourceInfo *TInfo, Expr *BW, bool Mutable,
                         InClassInitStyle InitStyle);

static FieldDecl *CreateDeserialized(ASTContext &C, unsigned ID);

/// Returns the index of this field within its record,
/// as appropriate for passing to ASTRecordLayout::getFieldOffset.
unsigned getFieldIndex() const;

/// Determines whether this field is mutable (C++ only).
bool isMutable() const { return Mutable; }

/// Determines whether this field is a bitfield.
bool isBitField() const { return BitField; }

/// Determines whether this is an unnamed bitfield.
bool isUnnamedBitfield() const { return isBitField() && !getDeclName(); }

/// Determines whether this field is a
/// representative for an anonymous struct or union. Such fields are
/// unnamed and are implicitly generated by the implementation to
/// store the data for the anonymous union or struct.
bool isAnonymousStructOrUnion() const;

Expr *getBitWidth() const {
  if (!BitField)
    return nullptr;
  void *Ptr = InitStorage.getPointer();
  if (getInClassInitStyle())
    return static_cast<InitAndBitWidth*>(Ptr)->BitWidth;
  return static_cast<Expr*>(Ptr);
}

unsigned getBitWidthValue(const ASTContext &Ctx) const;

/// Set the bit-field width for this member.
// Note: used by some clients (i.e., do not remove it).
void setBitWidth(Expr *Width) {
  assert(!hasCapturedVLAType() && !BitField &&((void)0)
         "bit width or captured type already set")((void)0);
  assert(Width && "no bit width specified")((void)0);
  InitStorage.setPointer(
      InitStorage.getInt()
          ? new (getASTContext())
                InitAndBitWidth{getInClassInitializer(), Width}
          : static_cast<void*>(Width));
  BitField = true;
}

/// Remove the bit-field width from this member.
// Note: used by some clients (i.e., do not remove it).
void removeBitWidth() {
  assert(isBitField() && "no bitfield width to remove")((void)0);
  InitStorage.setPointer(getInClassInitializer());
  BitField = false;
}

/// Is this a zero-length bit-field? Such bit-fields aren't really bit-fields
/// at all and instead act as a separator between contiguous runs of other
/// bit-fields.
bool isZeroLengthBitField(const ASTContext &Ctx) const;

/// Determine if this field is a subobject of zero size, that is, either a
/// zero-length bit-field or a field of empty class type with the
/// [[no_unique_address]] attribute.
bool isZeroSize(const ASTContext &Ctx) const;

/// Get the kind of (C++11) default member initializer that this field has.
InClassInitStyle getInClassInitStyle() const {
  InitStorageKind storageKind = InitStorage.getInt();
  return (storageKind == ISK_CapturedVLAType
            ? ICIS_NoInit : (InClassInitStyle) storageKind);
}

/// Determine whether this member has a C++11 default member initializer.
bool hasInClassInitializer() const {
  return getInClassInitStyle() != ICIS_NoInit;
}

/// Get the C++11 default member initializer for this member, or null if one
/// has not been set. If a valid declaration has a default member initializer,
/// but this returns null, then we have not parsed and attached it yet.
Expr *getInClassInitializer() const {
  if (!hasInClassInitializer())
    return nullptr;
  void *Ptr = InitStorage.getPointer();
  if (BitField)
    return static_cast<InitAndBitWidth*>(Ptr)->Init;
  return static_cast<Expr*>(Ptr);
}

/// Set the C++11 in-class initializer for this member.
void setInClassInitializer(Expr *Init) {
  assert(hasInClassInitializer() && !getInClassInitializer())((void)0);
  if (BitField)
    static_cast<InitAndBitWidth*>(InitStorage.getPointer())->Init = Init;
  else
    InitStorage.setPointer(Init);
}

/// Remove the C++11 in-class initializer from this member.
void removeInClassInitializer() {
  assert(hasInClassInitializer() && "no initializer to remove")((void)0);
  InitStorage.setPointerAndInt(getBitWidth(), ISK_NoInit);
}

/// Determine whether this member captures the variable length array
/// type.
bool hasCapturedVLAType() const {
  return InitStorage.getInt() == ISK_CapturedVLAType;
}

/// Get the captured variable length array type.
const VariableArrayType *getCapturedVLAType() const {
  return hasCapturedVLAType() ? static_cast<const VariableArrayType *>(
                                    InitStorage.getPointer())
                              : nullptr;
}

/// Set the captured variable length array type for this field.
void setCapturedVLAType(const VariableArrayType *VLAType);

/// Returns the parent of this field declaration, which
/// is the struct in which this field is defined.
///
/// Returns null if this is not a normal class/struct field declaration, e.g.
/// ObjCAtDefsFieldDecl, ObjCIvarDecl.
const RecordDecl *getParent() const {
  return dyn_cast<RecordDecl>(getDeclContext());
}

RecordDecl *getParent() {
  return dyn_cast<RecordDecl>(getDeclContext());
}

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

/// Retrieves the canonical declaration of this field.
FieldDecl *getCanonicalDecl() override { return getFirstDecl(); }
const FieldDecl *getCanonicalDecl() const { return getFirstDecl(); }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K >= firstField && K <= lastField; }
3034};

3036/// An instance of this object exists for each enum constant
3037/// that is defined.  For example, in "enum X {a,b}", each of a/b are
3038/// EnumConstantDecl's, X is an instance of EnumDecl, and the type of a/b is a
3039/// TagType for the X EnumDecl.
3040class EnumConstantDecl : public ValueDecl, public Mergeable<EnumConstantDecl> {
Stmt *Init; // an integer constant expression
llvm::APSInt Val; // The value.

3044protected:
EnumConstantDecl(DeclContext *DC, SourceLocation L,
                 IdentifierInfo *Id, QualType T, Expr *E,
                 const llvm::APSInt &V)
  : ValueDecl(EnumConstant, DC, L, Id, T), Init((Stmt*)E), Val(V) {}

3050public:
friend class StmtIteratorBase;

static EnumConstantDecl *Create(ASTContext &C, EnumDecl *DC,
                                SourceLocation L, IdentifierInfo *Id,
                                QualType T, Expr *E,
                                const llvm::APSInt &V);
static EnumConstantDecl *CreateDeserialized(ASTContext &C, unsigned ID);

const Expr *getInitExpr() const { return (const Expr*) Init; }
Expr *getInitExpr() { return (Expr*) Init; }
const llvm::APSInt &getInitVal() const { return Val; }

void setInitExpr(Expr *E) { Init = (Stmt*) E; }
void setInitVal(const llvm::APSInt &V) { Val = V; }

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

/// Retrieves the canonical declaration of this enumerator.
EnumConstantDecl *getCanonicalDecl() override { return getFirstDecl(); }
const EnumConstantDecl *getCanonicalDecl() const { return getFirstDecl(); }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == EnumConstant; }
3075};

3077/// Represents a field injected from an anonymous union/struct into the parent
3078/// scope. These are always implicit.
3079class IndirectFieldDecl : public ValueDecl,
                        public Mergeable<IndirectFieldDecl> {
NamedDecl **Chaining;
unsigned ChainingSize;

IndirectFieldDecl(ASTContext &C, DeclContext *DC, SourceLocation L,
                  DeclarationName N, QualType T,
                  MutableArrayRef<NamedDecl *> CH);

void anchor() override;

3090public:
friend class ASTDeclReader;

static IndirectFieldDecl *Create(ASTContext &C, DeclContext *DC,
                                 SourceLocation L, IdentifierInfo *Id,
                                 QualType T, llvm::MutableArrayRef<NamedDecl *> CH);

static IndirectFieldDecl *CreateDeserialized(ASTContext &C, unsigned ID);

using chain_iterator = ArrayRef<NamedDecl *>::const_iterator;

ArrayRef<NamedDecl *> chain() const {
  return llvm::makeArrayRef(Chaining, ChainingSize);
}
chain_iterator chain_begin() const { return chain().begin(); }
chain_iterator chain_end() const { return chain().end(); }

unsigned getChainingSize() const { return ChainingSize; }

FieldDecl *getAnonField() const {
  assert(chain().size() >= 2)((void)0);
  return cast<FieldDecl>(chain().back());
}

VarDecl *getVarDecl() const {
  assert(chain().size() >= 2)((void)0);
  return dyn_cast<VarDecl>(chain().front());
}

IndirectFieldDecl *getCanonicalDecl() override { return getFirstDecl(); }
const IndirectFieldDecl *getCanonicalDecl() const { return getFirstDecl(); }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == IndirectField; }
3125};

3127/// Represents a declaration of a type.
3128class TypeDecl : public NamedDecl {
friend class ASTContext;

/// This indicates the Type object that represents
/// this TypeDecl.  It is a cache maintained by
/// ASTContext::getTypedefType, ASTContext::getTagDeclType, and
/// ASTContext::getTemplateTypeParmType, and TemplateTypeParmDecl.
mutable const Type *TypeForDecl = nullptr;

/// The start of the source range for this declaration.
SourceLocation LocStart;

void anchor() override;

3142protected:
TypeDecl(Kind DK, DeclContext *DC, SourceLocation L, IdentifierInfo *Id,
         SourceLocation StartL = SourceLocation())
  : NamedDecl(DK, DC, L, Id), LocStart(StartL) {}

3147public:
// Low-level accessor. If you just want the type defined by this node,
// check out ASTContext::getTypeDeclType or one of
// ASTContext::getTypedefType, ASTContext::getRecordType, etc. if you
// already know the specific kind of node this is.
const Type *getTypeForDecl() const { return TypeForDecl; }
void setTypeForDecl(const Type *TD) { TypeForDecl = TD; }

SourceLocation getBeginLoc() const LLVM_READONLY__attribute__((__pure__)) { return LocStart; }
void setLocStart(SourceLocation L) { LocStart = L; }
SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__)) {
  if (LocStart.isValid())
    return SourceRange(LocStart, getLocation());
  else
    return SourceRange(getLocation());
}

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K >= firstType && K <= lastType; }
3167};

3169/// Base class for declarations which introduce a typedef-name.
3170class TypedefNameDecl : public TypeDecl, public Redeclarable<TypedefNameDecl> {
struct alignas(8) ModedTInfo {
  TypeSourceInfo *first;
  QualType second;
};

/// If int part is 0, we have not computed IsTransparentTag.
/// Otherwise, IsTransparentTag is (getInt() >> 1).
mutable llvm::PointerIntPair<
    llvm::PointerUnion<TypeSourceInfo *, ModedTInfo *>, 2>
    MaybeModedTInfo;

void anchor() override;

3184protected:
TypedefNameDecl(Kind DK, ASTContext &C, DeclContext *DC,
                SourceLocation StartLoc, SourceLocation IdLoc,
                IdentifierInfo *Id, TypeSourceInfo *TInfo)
    : TypeDecl(DK, DC, IdLoc, Id, StartLoc), redeclarable_base(C),
      MaybeModedTInfo(TInfo, 0) {}

using redeclarable_base = Redeclarable<TypedefNameDecl>;

TypedefNameDecl *getNextRedeclarationImpl() override {
  return getNextRedeclaration();
}

TypedefNameDecl *getPreviousDeclImpl() override {
  return getPreviousDecl();
}

TypedefNameDecl *getMostRecentDeclImpl() override {
  return getMostRecentDecl();
}

3205public:
using redecl_range = redeclarable_base::redecl_range;
using redecl_iterator = redeclarable_base::redecl_iterator;

using redeclarable_base::redecls_begin;
using redeclarable_base::redecls_end;
using redeclarable_base::redecls;
using redeclarable_base::getPreviousDecl;
using redeclarable_base::getMostRecentDecl;
using redeclarable_base::isFirstDecl;

bool isModed() const {
  return MaybeModedTInfo.getPointer().is<ModedTInfo *>();
}

TypeSourceInfo *getTypeSourceInfo() const {
  return isModed() ? MaybeModedTInfo.getPointer().get<ModedTInfo *>()->first
                   : MaybeModedTInfo.getPointer().get<TypeSourceInfo *>();
}

QualType getUnderlyingType() const {
  return isModed() ? MaybeModedTInfo.getPointer().get<ModedTInfo *>()->second
                   : MaybeModedTInfo.getPointer()
                         .get<TypeSourceInfo *>()
                         ->getType();
}

void setTypeSourceInfo(TypeSourceInfo *newType) {
  MaybeModedTInfo.setPointer(newType);
}

void setModedTypeSourceInfo(TypeSourceInfo *unmodedTSI, QualType modedTy) {
  MaybeModedTInfo.setPointer(new (getASTContext(), 8)
                                 ModedTInfo({unmodedTSI, modedTy}));
}

/// Retrieves the canonical declaration of this typedef-name.
TypedefNameDecl *getCanonicalDecl() override { return getFirstDecl(); }
const TypedefNameDecl *getCanonicalDecl() const { return getFirstDecl(); }

/// Retrieves the tag declaration for which this is the typedef name for
/// linkage purposes, if any.
///
/// \param AnyRedecl Look for the tag declaration in any redeclaration of
/// this typedef declaration.
TagDecl *getAnonDeclWithTypedefName(bool AnyRedecl = false) const;

/// Determines if this typedef shares a name and spelling location with its
/// underlying tag type, as is the case with the NS_ENUM macro.
bool isTransparentTag() const {
  if (MaybeModedTInfo.getInt())
    return MaybeModedTInfo.getInt() & 0x2;
  return isTransparentTagSlow();
}

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) {
  return K >= firstTypedefName && K <= lastTypedefName;
}

3266private:
bool isTransparentTagSlow() const;
3268};

3270/// Represents the declaration of a typedef-name via the 'typedef'
3271/// type specifier.
3272class TypedefDecl : public TypedefNameDecl {
TypedefDecl(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
            SourceLocation IdLoc, IdentifierInfo *Id, TypeSourceInfo *TInfo)
    : TypedefNameDecl(Typedef, C, DC, StartLoc, IdLoc, Id, TInfo) {}

3277public:
static TypedefDecl *Create(ASTContext &C, DeclContext *DC,
                           SourceLocation StartLoc, SourceLocation IdLoc,
                           IdentifierInfo *Id, TypeSourceInfo *TInfo);
static TypedefDecl *CreateDeserialized(ASTContext &C, unsigned ID);

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Typedef; }
3288};

3290/// Represents the declaration of a typedef-name via a C++11
3291/// alias-declaration.
3292class TypeAliasDecl : public TypedefNameDecl {
/// The template for which this is the pattern, if any.
TypeAliasTemplateDecl *Template;

TypeAliasDecl(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
              SourceLocation IdLoc, IdentifierInfo *Id, TypeSourceInfo *TInfo)
    : TypedefNameDecl(TypeAlias, C, DC, StartLoc, IdLoc, Id, TInfo),
      Template(nullptr) {}

3301public:
static TypeAliasDecl *Create(ASTContext &C, DeclContext *DC,
                             SourceLocation StartLoc, SourceLocation IdLoc,
                             IdentifierInfo *Id, TypeSourceInfo *TInfo);
static TypeAliasDecl *CreateDeserialized(ASTContext &C, unsigned ID);

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

TypeAliasTemplateDecl *getDescribedAliasTemplate() const { return Template; }
void setDescribedAliasTemplate(TypeAliasTemplateDecl *TAT) { Template = TAT; }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == TypeAlias; }
3315};

3317/// Represents the declaration of a struct/union/class/enum.
3318class TagDecl : public TypeDecl,
              public DeclContext,
              public Redeclarable<TagDecl> {
// This class stores some data in DeclContext::TagDeclBits
// to save some space. Use the provided accessors to access it.
3323public:
// This is really ugly.
using TagKind = TagTypeKind;

3327private:
SourceRange BraceRange;

// A struct representing syntactic qualifier info,
// to be used for the (uncommon) case of out-of-line declarations.
using ExtInfo = QualifierInfo;

/// If the (out-of-line) tag declaration name
/// is qualified, it points to the qualifier info (nns and range);
/// otherwise, if the tag declaration is anonymous and it is part of
/// a typedef or alias, it points to the TypedefNameDecl (used for mangling);
/// otherwise, if the tag declaration is anonymous and it is used as a
/// declaration specifier for variables, it points to the first VarDecl (used
/// for mangling);
/// otherwise, it is a null (TypedefNameDecl) pointer.
llvm::PointerUnion<TypedefNameDecl *, ExtInfo *> TypedefNameDeclOrQualifier;

bool hasExtInfo() const { return TypedefNameDeclOrQualifier.is<ExtInfo *>(); }
ExtInfo *getExtInfo() { return TypedefNameDeclOrQualifier.get<ExtInfo *>(); }
const ExtInfo *getExtInfo() const {
  return TypedefNameDeclOrQualifier.get<ExtInfo *>();
}

3350protected:
TagDecl(Kind DK, TagKind TK, const ASTContext &C, DeclContext *DC,
        SourceLocation L, IdentifierInfo *Id, TagDecl *PrevDecl,
        SourceLocation StartL);

using redeclarable_base = Redeclarable<TagDecl>;

TagDecl *getNextRedeclarationImpl() override {
  return getNextRedeclaration();
}

TagDecl *getPreviousDeclImpl() override {
  return getPreviousDecl();
}

TagDecl *getMostRecentDeclImpl() override {
  return getMostRecentDecl();
}

/// Completes the definition of this tag declaration.
///
/// This is a helper function for derived classes.
void completeDefinition();

/// True if this decl is currently being defined.
void setBeingDefined(bool V = true) { TagDeclBits.IsBeingDefined = V; }

/// Indicates whether it is possible for declarations of this kind
/// to have an out-of-date definition.
///
/// This option is only enabled when modules are enabled.
void setMayHaveOutOfDateDef(bool V = true) {
  TagDeclBits.MayHaveOutOfDateDef = V;
}

3385public:
friend class ASTDeclReader;
friend class ASTDeclWriter;

using redecl_range = redeclarable_base::redecl_range;
using redecl_iterator = redeclarable_base::redecl_iterator;

using redeclarable_base::redecls_begin;
using redeclarable_base::redecls_end;
using redeclarable_base::redecls;
using redeclarable_base::getPreviousDecl;
using redeclarable_base::getMostRecentDecl;
using redeclarable_base::isFirstDecl;

SourceRange getBraceRange() const { return BraceRange; }
void setBraceRange(SourceRange R) { BraceRange = R; }

/// Return SourceLocation representing start of source
/// range ignoring outer template declarations.
SourceLocation getInnerLocStart() const { return getBeginLoc(); }

/// Return SourceLocation representing start of source
/// range taking into account any outer template declarations.
SourceLocation getOuterLocStart() const;
SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

TagDecl *getCanonicalDecl() override;
const TagDecl *getCanonicalDecl() const {
  return const_cast<TagDecl*>(this)->getCanonicalDecl();
}

/// Return true if this declaration is a completion definition of the type.
/// Provided for consistency.
bool isThisDeclarationADefinition() const {
  return isCompleteDefinition();
}

/// Return true if this decl has its body fully specified.
bool isCompleteDefinition() const { return TagDeclBits.IsCompleteDefinition; }

/// True if this decl has its body fully specified.
void setCompleteDefinition(bool V = true) {
  TagDeclBits.IsCompleteDefinition = V;
}

/// Return true if this complete decl is
/// required to be complete for some existing use.
bool isCompleteDefinitionRequired() const {
  return TagDeclBits.IsCompleteDefinitionRequired;
}

/// True if this complete decl is
/// required to be complete for some existing use.
void setCompleteDefinitionRequired(bool V = true) {
  TagDeclBits.IsCompleteDefinitionRequired = V;
}

/// Return true if this decl is currently being defined.
bool isBeingDefined() const { return TagDeclBits.IsBeingDefined; }

/// True if this tag declaration is "embedded" (i.e., defined or declared
/// for the very first time) in the syntax of a declarator.
bool isEmbeddedInDeclarator() const {
  return TagDeclBits.IsEmbeddedInDeclarator;
}

/// True if this tag declaration is "embedded" (i.e., defined or declared
/// for the very first time) in the syntax of a declarator.
void setEmbeddedInDeclarator(bool isInDeclarator) {
  TagDeclBits.IsEmbeddedInDeclarator = isInDeclarator;
}

/// True if this tag is free standing, e.g. "struct foo;".
bool isFreeStanding() const { return TagDeclBits.IsFreeStanding; }

/// True if this tag is free standing, e.g. "struct foo;".
void setFreeStanding(bool isFreeStanding = true) {
  TagDeclBits.IsFreeStanding = isFreeStanding;
}

/// Indicates whether it is possible for declarations of this kind
/// to have an out-of-date definition.
///
/// This option is only enabled when modules are enabled.
bool mayHaveOutOfDateDef() const { return TagDeclBits.MayHaveOutOfDateDef; }

/// Whether this declaration declares a type that is
/// dependent, i.e., a type that somehow depends on template
/// parameters.
bool isDependentType() const { return isDependentContext(); }

/// Starts the definition of this tag declaration.
///
/// This method should be invoked at the beginning of the definition
/// of this tag declaration. It will set the tag type into a state
/// where it is in the process of being defined.
void startDefinition();

/// Returns the TagDecl that actually defines this
///  struct/union/class/enum.  When determining whether or not a
///  struct/union/class/enum has a definition, one should use this
///  method as opposed to 'isDefinition'.  'isDefinition' indicates
///  whether or not a specific TagDecl is defining declaration, not
///  whether or not the struct/union/class/enum type is defined.
///  This method returns NULL if there is no TagDecl that defines
///  the struct/union/class/enum.
TagDecl *getDefinition() const;

StringRef getKindName() const {
  return TypeWithKeyword::getTagTypeKindName(getTagKind());
}

TagKind getTagKind() const {
  return static_cast<TagKind>(TagDeclBits.TagDeclKind);
}

void setTagKind(TagKind TK) { TagDeclBits.TagDeclKind = TK; }

bool isStruct() const { return getTagKind() == TTK_Struct; }
bool isInterface() const { return getTagKind() == TTK_Interface; }
bool isClass()  const { return getTagKind() == TTK_Class; }
bool isUnion()  const { return getTagKind() == TTK_Union; }
33
←
Assuming the condition is false→
34
←
Returning zero, which participates in a condition later→
39
←
Assuming the condition is true→
40
←
Returning the value 1, which participates in a condition later→
bool isEnum()   const { return getTagKind() == TTK_Enum; }

/// Is this tag type named, either directly or via being defined in
/// a typedef of this type?
///
/// C++11 [basic.link]p8:
///   A type is said to have linkage if and only if:
///     - it is a class or enumeration type that is named (or has a
///       name for linkage purposes) and the name has linkage; ...
/// C++11 [dcl.typedef]p9:
///   If the typedef declaration defines an unnamed class (or enum),
///   the first typedef-name declared by the declaration to be that
///   class type (or enum type) is used to denote the class type (or
///   enum type) for linkage purposes only.
///
/// C does not have an analogous rule, but the same concept is
/// nonetheless useful in some places.
bool hasNameForLinkage() const {
  return (getDeclName() || getTypedefNameForAnonDecl());
}

TypedefNameDecl *getTypedefNameForAnonDecl() const {
  return hasExtInfo() ? nullptr
                      : TypedefNameDeclOrQualifier.get<TypedefNameDecl *>();
}

void setTypedefNameForAnonDecl(TypedefNameDecl *TDD);

/// Retrieve the nested-name-specifier that qualifies the name of this
/// declaration, if it was present in the source.
NestedNameSpecifier *getQualifier() const {
  return hasExtInfo() ? getExtInfo()->QualifierLoc.getNestedNameSpecifier()
                      : nullptr;
}

/// Retrieve the nested-name-specifier (with source-location
/// information) that qualifies the name of this declaration, if it was
/// present in the source.
NestedNameSpecifierLoc getQualifierLoc() const {
  return hasExtInfo() ? getExtInfo()->QualifierLoc
                      : NestedNameSpecifierLoc();
}

void setQualifierInfo(NestedNameSpecifierLoc QualifierLoc);

unsigned getNumTemplateParameterLists() const {
  return hasExtInfo() ? getExtInfo()->NumTemplParamLists : 0;
}

TemplateParameterList *getTemplateParameterList(unsigned i) const {
  assert(i < getNumTemplateParameterLists())((void)0);
  return getExtInfo()->TemplParamLists[i];
}

void setTemplateParameterListsInfo(ASTContext &Context,
                                   ArrayRef<TemplateParameterList *> TPLists);

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K >= firstTag && K <= lastTag; }

static DeclContext *castToDeclContext(const TagDecl *D) {
  return static_cast<DeclContext *>(const_cast<TagDecl*>(D));
}

static TagDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<TagDecl *>(const_cast<DeclContext*>(DC));
}
3575};

3577/// Represents an enum.  In C++11, enums can be forward-declared
3578/// with a fixed underlying type, and in C we allow them to be forward-declared
3579/// with no underlying type as an extension.
3580class EnumDecl : public TagDecl {
// This class stores some data in DeclContext::EnumDeclBits
// to save some space. Use the provided accessors to access it.

/// This represent the integer type that the enum corresponds
/// to for code generation purposes.  Note that the enumerator constants may
/// have a different type than this does.
///
/// If the underlying integer type was explicitly stated in the source
/// code, this is a TypeSourceInfo* for that type. Otherwise this type
/// was automatically deduced somehow, and this is a Type*.
///
/// Normally if IsFixed(), this would contain a TypeSourceInfo*, but in
/// some cases it won't.
///
/// The underlying type of an enumeration never has any qualifiers, so
/// we can get away with just storing a raw Type*, and thus save an
/// extra pointer when TypeSourceInfo is needed.
llvm::PointerUnion<const Type *, TypeSourceInfo *> IntegerType;

/// The integer type that values of this type should
/// promote to.  In C, enumerators are generally of an integer type
/// directly, but gcc-style large enumerators (and all enumerators
/// in C++) are of the enum type instead.
QualType PromotionType;

/// If this enumeration is an instantiation of a member enumeration
/// of a class template specialization, this is the member specialization
/// information.
MemberSpecializationInfo *SpecializationInfo = nullptr;

/// Store the ODRHash after first calculation.
/// The corresponding flag HasODRHash is in EnumDeclBits
/// and can be accessed with the provided accessors.
unsigned ODRHash;

EnumDecl(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
         SourceLocation IdLoc, IdentifierInfo *Id, EnumDecl *PrevDecl,
         bool Scoped, bool ScopedUsingClassTag, bool Fixed);

void anchor() override;

void setInstantiationOfMemberEnum(ASTContext &C, EnumDecl *ED,
                                  TemplateSpecializationKind TSK);

/// Sets the width in bits required to store all the
/// non-negative enumerators of this enum.
void setNumPositiveBits(unsigned Num) {
  EnumDeclBits.NumPositiveBits = Num;
  assert(EnumDeclBits.NumPositiveBits == Num && "can't store this bitcount")((void)0);
}

/// Returns the width in bits required to store all the
/// negative enumerators of this enum. (see getNumNegativeBits)
void setNumNegativeBits(unsigned Num) { EnumDeclBits.NumNegativeBits = Num; }

3636public:
/// True if this tag declaration is a scoped enumeration. Only
/// possible in C++11 mode.
void setScoped(bool Scoped = true) { EnumDeclBits.IsScoped = Scoped; }

/// If this tag declaration is a scoped enum,
/// then this is true if the scoped enum was declared using the class
/// tag, false if it was declared with the struct tag. No meaning is
/// associated if this tag declaration is not a scoped enum.
void setScopedUsingClassTag(bool ScopedUCT = true) {
  EnumDeclBits.IsScopedUsingClassTag = ScopedUCT;
}

/// True if this is an Objective-C, C++11, or
/// Microsoft-style enumeration with a fixed underlying type.
void setFixed(bool Fixed = true) { EnumDeclBits.IsFixed = Fixed; }

3653private:
/// True if a valid hash is stored in ODRHash.
bool hasODRHash() const { return EnumDeclBits.HasODRHash; }
void setHasODRHash(bool Hash = true) { EnumDeclBits.HasODRHash = Hash; }

3658public:
friend class ASTDeclReader;

EnumDecl *getCanonicalDecl() override {
  return cast<EnumDecl>(TagDecl::getCanonicalDecl());
}
const EnumDecl *getCanonicalDecl() const {
  return const_cast<EnumDecl*>(this)->getCanonicalDecl();
}

EnumDecl *getPreviousDecl() {
  return cast_or_null<EnumDecl>(
          static_cast<TagDecl *>(this)->getPreviousDecl());
}
const EnumDecl *getPreviousDecl() const {
  return const_cast<EnumDecl*>(this)->getPreviousDecl();
}

EnumDecl *getMostRecentDecl() {
  return cast<EnumDecl>(static_cast<TagDecl *>(this)->getMostRecentDecl());
}
const EnumDecl *getMostRecentDecl() const {
  return const_cast<EnumDecl*>(this)->getMostRecentDecl();
}

EnumDecl *getDefinition() const {
  return cast_or_null<EnumDecl>(TagDecl::getDefinition());
}

static EnumDecl *Create(ASTContext &C, DeclContext *DC,
                        SourceLocation StartLoc, SourceLocation IdLoc,
                        IdentifierInfo *Id, EnumDecl *PrevDecl,
                        bool IsScoped, bool IsScopedUsingClassTag,
                        bool IsFixed);
static EnumDecl *CreateDeserialized(ASTContext &C, unsigned ID);

/// When created, the EnumDecl corresponds to a
/// forward-declared enum. This method is used to mark the
/// declaration as being defined; its enumerators have already been
/// added (via DeclContext::addDecl). NewType is the new underlying
/// type of the enumeration type.
void completeDefinition(QualType NewType,
                        QualType PromotionType,
                        unsigned NumPositiveBits,
                        unsigned NumNegativeBits);

// Iterates through the enumerators of this enumeration.
using enumerator_iterator = specific_decl_iterator<EnumConstantDecl>;
using enumerator_range =
    llvm::iterator_range<specific_decl_iterator<EnumConstantDecl>>;

enumerator_range enumerators() const {
  return enumerator_range(enumerator_begin(), enumerator_end());
}

enumerator_iterator enumerator_begin() const {
  const EnumDecl *E = getDefinition();
  if (!E)
    E = this;
  return enumerator_iterator(E->decls_begin());
}

enumerator_iterator enumerator_end() const {
  const EnumDecl *E = getDefinition();
  if (!E)
    E = this;
  return enumerator_iterator(E->decls_end());
}

/// Return the integer type that enumerators should promote to.
QualType getPromotionType() const { return PromotionType; }

/// Set the promotion type.
void setPromotionType(QualType T) { PromotionType = T; }

/// Return the integer type this enum decl corresponds to.
/// This returns a null QualType for an enum forward definition with no fixed
/// underlying type.
QualType getIntegerType() const {
  if (!IntegerType)
    return QualType();
  if (const Type *T = IntegerType.dyn_cast<const Type*>())
    return QualType(T, 0);
  return IntegerType.get<TypeSourceInfo*>()->getType().getUnqualifiedType();
}

/// Set the underlying integer type.
void setIntegerType(QualType T) { IntegerType = T.getTypePtrOrNull(); }

/// Set the underlying integer type source info.
void setIntegerTypeSourceInfo(TypeSourceInfo *TInfo) { IntegerType = TInfo; }

/// Return the type source info for the underlying integer type,
/// if no type source info exists, return 0.
TypeSourceInfo *getIntegerTypeSourceInfo() const {
  return IntegerType.dyn_cast<TypeSourceInfo*>();
}

/// Retrieve the source range that covers the underlying type if
/// specified.
SourceRange getIntegerTypeRange() const LLVM_READONLY__attribute__((__pure__));

/// Returns the width in bits required to store all the
/// non-negative enumerators of this enum.
unsigned getNumPositiveBits() const { return EnumDeclBits.NumPositiveBits; }

/// Returns the width in bits required to store all the
/// negative enumerators of this enum.  These widths include
/// the rightmost leading 1;  that is:
///
/// MOST NEGATIVE ENUMERATOR     PATTERN     NUM NEGATIVE BITS
/// ------------------------     -------     -----------------
///                       -1     1111111                     1
///                      -10     1110110                     5
///                     -101     1001011                     8
unsigned getNumNegativeBits() const { return EnumDeclBits.NumNegativeBits; }

/// Returns true if this is a C++11 scoped enumeration.
bool isScoped() const { return EnumDeclBits.IsScoped; }

/// Returns true if this is a C++11 scoped enumeration.
bool isScopedUsingClassTag() const {
  return EnumDeclBits.IsScopedUsingClassTag;
}

/// Returns true if this is an Objective-C, C++11, or
/// Microsoft-style enumeration with a fixed underlying type.
bool isFixed() const { return EnumDeclBits.IsFixed; }

unsigned getODRHash();

/// Returns true if this can be considered a complete type.
bool isComplete() const {
  // IntegerType is set for fixed type enums and non-fixed but implicitly
  // int-sized Microsoft enums.
  return isCompleteDefinition() || IntegerType;
}

/// Returns true if this enum is either annotated with
/// enum_extensibility(closed) or isn't annotated with enum_extensibility.
bool isClosed() const;

/// Returns true if this enum is annotated with flag_enum and isn't annotated
/// with enum_extensibility(open).
bool isClosedFlag() const;

/// Returns true if this enum is annotated with neither flag_enum nor
/// enum_extensibility(open).
bool isClosedNonFlag() const;

/// Retrieve the enum definition from which this enumeration could
/// be instantiated, if it is an instantiation (rather than a non-template).
EnumDecl *getTemplateInstantiationPattern() const;

/// Returns the enumeration (declared within the template)
/// from which this enumeration type was instantiated, or NULL if
/// this enumeration was not instantiated from any template.
EnumDecl *getInstantiatedFromMemberEnum() const;

/// If this enumeration is a member of a specialization of a
/// templated class, determine what kind of template specialization
/// or instantiation this is.
TemplateSpecializationKind getTemplateSpecializationKind() const;

/// For an enumeration member that was instantiated from a member
/// enumeration of a templated class, set the template specialiation kind.
void setTemplateSpecializationKind(TemplateSpecializationKind TSK,
                      SourceLocation PointOfInstantiation = SourceLocation());

/// If this enumeration is an instantiation of a member enumeration of
/// a class template specialization, retrieves the member specialization
/// information.
MemberSpecializationInfo *getMemberSpecializationInfo() const {
  return SpecializationInfo;
}

/// Specify that this enumeration is an instantiation of the
/// member enumeration ED.
void setInstantiationOfMemberEnum(EnumDecl *ED,
                                  TemplateSpecializationKind TSK) {
  setInstantiationOfMemberEnum(getASTContext(), ED, TSK);
}

static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Enum; }
3843};

3845/// Represents a struct/union/class.  For example:
3846///   struct X;                  // Forward declaration, no "body".
3847///   union Y { int A, B; };     // Has body with members A and B (FieldDecls).
3848/// This decl will be marked invalid if *any* members are invalid.
3849class RecordDecl : public TagDecl {
// This class stores some data in DeclContext::RecordDeclBits
// to save some space. Use the provided accessors to access it.
3852public:
friend class DeclContext;
/// Enum that represents the different ways arguments are passed to and
/// returned from function calls. This takes into account the target-specific
/// and version-specific rules along with the rules determined by the
/// language.
enum ArgPassingKind : unsigned {
  /// The argument of this type can be passed directly in registers.
  APK_CanPassInRegs,

  /// The argument of this type cannot be passed directly in registers.
  /// Records containing this type as a subobject are not forced to be passed
  /// indirectly. This value is used only in C++. This value is required by
  /// C++ because, in uncommon situations, it is possible for a class to have
  /// only trivial copy/move constructors even when one of its subobjects has
  /// a non-trivial copy/move constructor (if e.g. the corresponding copy/move
  /// constructor in the derived class is deleted).
  APK_CannotPassInRegs,

  /// The argument of this type cannot be passed directly in registers.
  /// Records containing this type as a subobject are forced to be passed
  /// indirectly.
  APK_CanNeverPassInRegs
};

3877protected:
RecordDecl(Kind DK, TagKind TK, const ASTContext &C, DeclContext *DC,
           SourceLocation StartLoc, SourceLocation IdLoc,
           IdentifierInfo *Id, RecordDecl *PrevDecl);

3882public:
static RecordDecl *Create(const ASTContext &C, TagKind TK, DeclContext *DC,
                          SourceLocation StartLoc, SourceLocation IdLoc,
                          IdentifierInfo *Id, RecordDecl* PrevDecl = nullptr);
static RecordDecl *CreateDeserialized(const ASTContext &C, unsigned ID);

RecordDecl *getPreviousDecl() {
  return cast_or_null<RecordDecl>(
          static_cast<TagDecl *>(this)->getPreviousDecl());
}
const RecordDecl *getPreviousDecl() const {
  return const_cast<RecordDecl*>(this)->getPreviousDecl();
}

RecordDecl *getMostRecentDecl() {
  return cast<RecordDecl>(static_cast<TagDecl *>(this)->getMostRecentDecl());
}
const RecordDecl *getMostRecentDecl() const {
  return const_cast<RecordDecl*>(this)->getMostRecentDecl();
}

bool hasFlexibleArrayMember() const {
  return RecordDeclBits.HasFlexibleArrayMember;
}

void setHasFlexibleArrayMember(bool V) {
  RecordDeclBits.HasFlexibleArrayMember = V;
}

/// Whether this is an anonymous struct or union. To be an anonymous
/// struct or union, it must have been declared without a name and
/// there must be no objects of this type declared, e.g.,
/// @code
///   union { int i; float f; };
/// @endcode
/// is an anonymous union but neither of the following are:
/// @code
///  union X { int i; float f; };
///  union { int i; float f; } obj;
/// @endcode
bool isAnonymousStructOrUnion() const {
  return RecordDeclBits.AnonymousStructOrUnion;
}

void setAnonymousStructOrUnion(bool Anon) {
  RecordDeclBits.AnonymousStructOrUnion = Anon;
}

bool hasObjectMember() const { return RecordDeclBits.HasObjectMember; }
void setHasObjectMember(bool val) { RecordDeclBits.HasObjectMember = val; }

bool hasVolatileMember() const { return RecordDeclBits.HasVolatileMember; }

void setHasVolatileMember(bool val) {
  RecordDeclBits.HasVolatileMember = val;
}

bool hasLoadedFieldsFromExternalStorage() const {
  return RecordDeclBits.LoadedFieldsFromExternalStorage;
}

void setHasLoadedFieldsFromExternalStorage(bool val) const {
  RecordDeclBits.LoadedFieldsFromExternalStorage = val;
}

/// Functions to query basic properties of non-trivial C structs.
bool isNonTrivialToPrimitiveDefaultInitialize() const {
  return RecordDeclBits.NonTrivialToPrimitiveDefaultInitialize;
}

void setNonTrivialToPrimitiveDefaultInitialize(bool V) {
  RecordDeclBits.NonTrivialToPrimitiveDefaultInitialize = V;
}

bool isNonTrivialToPrimitiveCopy() const {
  return RecordDeclBits.NonTrivialToPrimitiveCopy;
}

void setNonTrivialToPrimitiveCopy(bool V) {
  RecordDeclBits.NonTrivialToPrimitiveCopy = V;
}

bool isNonTrivialToPrimitiveDestroy() const {
  return RecordDeclBits.NonTrivialToPrimitiveDestroy;
}

void setNonTrivialToPrimitiveDestroy(bool V) {
  RecordDeclBits.NonTrivialToPrimitiveDestroy = V;
}

bool hasNonTrivialToPrimitiveDefaultInitializeCUnion() const {
  return RecordDeclBits.HasNonTrivialToPrimitiveDefaultInitializeCUnion;
}

void setHasNonTrivialToPrimitiveDefaultInitializeCUnion(bool V) {
  RecordDeclBits.HasNonTrivialToPrimitiveDefaultInitializeCUnion = V;
}

bool hasNonTrivialToPrimitiveDestructCUnion() const {
  return RecordDeclBits.HasNonTrivialToPrimitiveDestructCUnion;
}

void setHasNonTrivialToPrimitiveDestructCUnion(bool V) {
  RecordDeclBits.HasNonTrivialToPrimitiveDestructCUnion = V;
}

bool hasNonTrivialToPrimitiveCopyCUnion() const {
  return RecordDeclBits.HasNonTrivialToPrimitiveCopyCUnion;
}

void setHasNonTrivialToPrimitiveCopyCUnion(bool V) {
  RecordDeclBits.HasNonTrivialToPrimitiveCopyCUnion = V;
}

/// Determine whether this class can be passed in registers. In C++ mode,
/// it must have at least one trivial, non-deleted copy or move constructor.
/// FIXME: This should be set as part of completeDefinition.
bool canPassInRegisters() const {
  return getArgPassingRestrictions() == APK_CanPassInRegs;
}

ArgPassingKind getArgPassingRestrictions() const {
  return static_cast<ArgPassingKind>(RecordDeclBits.ArgPassingRestrictions);
}

void setArgPassingRestrictions(ArgPassingKind Kind) {
  RecordDeclBits.ArgPassingRestrictions = Kind;
}

bool isParamDestroyedInCallee() const {
  return RecordDeclBits.ParamDestroyedInCallee;
}

void setParamDestroyedInCallee(bool V) {
  RecordDeclBits.ParamDestroyedInCallee = V;
}

/// Determines whether this declaration represents the
/// injected class name.
///
/// The injected class name in C++ is the name of the class that
/// appears inside the class itself. For example:
///
/// \code
/// struct C {
///   // C is implicitly declared here as a synonym for the class name.
/// };
///
/// C::C c; // same as "C c;"
/// \endcode
bool isInjectedClassName() const;

/// Determine whether this record is a class describing a lambda
/// function object.
bool isLambda() const;

/// Determine whether this record is a record for captured variables in
/// CapturedStmt construct.
bool isCapturedRecord() const;

/// Mark the record as a record for captured variables in CapturedStmt
/// construct.
void setCapturedRecord();

/// Returns the RecordDecl that actually defines
///  this struct/union/class.  When determining whether or not a
///  struct/union/class is completely defined, one should use this
///  method as opposed to 'isCompleteDefinition'.
///  'isCompleteDefinition' indicates whether or not a specific
///  RecordDecl is a completed definition, not whether or not the
///  record type is defined.  This method returns NULL if there is
///  no RecordDecl that defines the struct/union/tag.
RecordDecl *getDefinition() const {
  return cast_or_null<RecordDecl>(TagDecl::getDefinition());
}

/// Returns whether this record is a union, or contains (at any nesting level)
/// a union member. This is used by CMSE to warn about possible information
/// leaks.
bool isOrContainsUnion() const;

// Iterator access to field members. The field iterator only visits
// the non-static data members of this class, ignoring any static
// data members, functions, constructors, destructors, etc.
using field_iterator = specific_decl_iterator<FieldDecl>;
using field_range = llvm::iterator_range<specific_decl_iterator<FieldDecl>>;

field_range fields() const { return field_range(field_begin(), field_end()); }
field_iterator field_begin() const;

field_iterator field_end() const {
  return field_iterator(decl_iterator());
}

// Whether there are any fields (non-static data members) in this record.
bool field_empty() const {
  return field_begin() == field_end();
44
←
Calling 'operator=='→
50
←
Returning from 'operator=='→
51
←
Returning zero, which participates in a condition later→
}

/// Note that the definition of this type is now complete.
virtual void completeDefinition();

static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) {
  return K >= firstRecord && K <= lastRecord;
}

/// Get whether or not this is an ms_struct which can
/// be turned on with an attribute, pragma, or -mms-bitfields
/// commandline option.
bool isMsStruct(const ASTContext &C) const;

/// Whether we are allowed to insert extra padding between fields.
/// These padding are added to help AddressSanitizer detect
/// intra-object-overflow bugs.
bool mayInsertExtraPadding(bool EmitRemark = false) const;

/// Finds the first data member which has a name.
/// nullptr is returned if no named data member exists.
const FieldDecl *findFirstNamedDataMember() const;

4103private:
/// Deserialize just the fields.
void LoadFieldsFromExternalStorage() const;
4106};

4108class FileScopeAsmDecl : public Decl {
StringLiteral *AsmString;
SourceLocation RParenLoc;

FileScopeAsmDecl(DeclContext *DC, StringLiteral *asmstring,
                 SourceLocation StartL, SourceLocation EndL)
  : Decl(FileScopeAsm, DC, StartL), AsmString(asmstring), RParenLoc(EndL) {}

virtual void anchor();

4118public:
static FileScopeAsmDecl *Create(ASTContext &C, DeclContext *DC,
                                StringLiteral *Str, SourceLocation AsmLoc,
                                SourceLocation RParenLoc);

static FileScopeAsmDecl *CreateDeserialized(ASTContext &C, unsigned ID);

SourceLocation getAsmLoc() const { return getLocation(); }
SourceLocation getRParenLoc() const { return RParenLoc; }
void setRParenLoc(SourceLocation L) { RParenLoc = L; }
SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__)) {
  return SourceRange(getAsmLoc(), getRParenLoc());
}

const StringLiteral *getAsmString() const { return AsmString; }
StringLiteral *getAsmString() { return AsmString; }
void setAsmString(StringLiteral *Asm) { AsmString = Asm; }

static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == FileScopeAsm; }
4138};

4140/// Represents a block literal declaration, which is like an
4141/// unnamed FunctionDecl.  For example:
4142/// ^{ statement-body }   or   ^(int arg1, float arg2){ statement-body }
4143class BlockDecl : public Decl, public DeclContext {
// This class stores some data in DeclContext::BlockDeclBits
// to save some space. Use the provided accessors to access it.
4146public:
/// A class which contains all the information about a particular
/// captured value.
class Capture {
  enum {
    flag_isByRef = 0x1,
    flag_isNested = 0x2
  };

  /// The variable being captured.
  llvm::PointerIntPair<VarDecl*, 2> VariableAndFlags;

  /// The copy expression, expressed in terms of a DeclRef (or
  /// BlockDeclRef) to the captured variable.  Only required if the
  /// variable has a C++ class type.
  Expr *CopyExpr;

public:
  Capture(VarDecl *variable, bool byRef, bool nested, Expr *copy)
    : VariableAndFlags(variable,
                (byRef ? flag_isByRef : 0) | (nested ? flag_isNested : 0)),
      CopyExpr(copy) {}

  /// The variable being captured.
  VarDecl *getVariable() const { return VariableAndFlags.getPointer(); }

  /// Whether this is a "by ref" capture, i.e. a capture of a __block
  /// variable.
  bool isByRef() const { return VariableAndFlags.getInt() & flag_isByRef; }

  bool isEscapingByref() const {
    return getVariable()->isEscapingByref();
  }

  bool isNonEscapingByref() const {
    return getVariable()->isNonEscapingByref();
  }

  /// Whether this is a nested capture, i.e. the variable captured
  /// is not from outside the immediately enclosing function/block.
  bool isNested() const { return VariableAndFlags.getInt() & flag_isNested; }

  bool hasCopyExpr() const { return CopyExpr != nullptr; }
  Expr *getCopyExpr() const { return CopyExpr; }
  void setCopyExpr(Expr *e) { CopyExpr = e; }
};

4193private:
/// A new[]'d array of pointers to ParmVarDecls for the formal
/// parameters of this function.  This is null if a prototype or if there are
/// no formals.
ParmVarDecl **ParamInfo = nullptr;
unsigned NumParams = 0;

Stmt *Body = nullptr;
TypeSourceInfo *SignatureAsWritten = nullptr;

const Capture *Captures = nullptr;
unsigned NumCaptures = 0;

unsigned ManglingNumber = 0;
Decl *ManglingContextDecl = nullptr;

4209protected:
BlockDecl(DeclContext *DC, SourceLocation CaretLoc);

4212public:
static BlockDecl *Create(ASTContext &C, DeclContext *DC, SourceLocation L);
static BlockDecl *CreateDeserialized(ASTContext &C, unsigned ID);

SourceLocation getCaretLocation() const { return getLocation(); }

bool isVariadic() const { return BlockDeclBits.IsVariadic; }
void setIsVariadic(bool value) { BlockDeclBits.IsVariadic = value; }

CompoundStmt *getCompoundBody() const { return (CompoundStmt*) Body; }
Stmt *getBody() const override { return (Stmt*) Body; }
void setBody(CompoundStmt *B) { Body = (Stmt*) B; }

void setSignatureAsWritten(TypeSourceInfo *Sig) { SignatureAsWritten = Sig; }
TypeSourceInfo *getSignatureAsWritten() const { return SignatureAsWritten; }

// ArrayRef access to formal parameters.
ArrayRef<ParmVarDecl *> parameters() const {
  return {ParamInfo, getNumParams()};
}
MutableArrayRef<ParmVarDecl *> parameters() {
  return {ParamInfo, getNumParams()};
}

// Iterator access to formal parameters.
using param_iterator = MutableArrayRef<ParmVarDecl *>::iterator;
using param_const_iterator = ArrayRef<ParmVarDecl *>::const_iterator;

bool param_empty() const { return parameters().empty(); }
param_iterator param_begin() { return parameters().begin(); }
param_iterator param_end() { return parameters().end(); }
param_const_iterator param_begin() const { return parameters().begin(); }
param_const_iterator param_end() const { return parameters().end(); }
size_t param_size() const { return parameters().size(); }

unsigned getNumParams() const { return NumParams; }

const ParmVarDecl *getParamDecl(unsigned i) const {
  assert(i < getNumParams() && "Illegal param #")((void)0);
  return ParamInfo[i];
}
ParmVarDecl *getParamDecl(unsigned i) {
  assert(i < getNumParams() && "Illegal param #")((void)0);
  return ParamInfo[i];
}

void setParams(ArrayRef<ParmVarDecl *> NewParamInfo);

/// True if this block (or its nested blocks) captures
/// anything of local storage from its enclosing scopes.
bool hasCaptures() const { return NumCaptures || capturesCXXThis(); }

/// Returns the number of captured variables.
/// Does not include an entry for 'this'.
unsigned getNumCaptures() const { return NumCaptures; }

using capture_const_iterator = ArrayRef<Capture>::const_iterator;

ArrayRef<Capture> captures() const { return {Captures, NumCaptures}; }

capture_const_iterator capture_begin() const { return captures().begin(); }
capture_const_iterator capture_end() const { return captures().end(); }

bool capturesCXXThis() const { return BlockDeclBits.CapturesCXXThis; }
void setCapturesCXXThis(bool B = true) { BlockDeclBits.CapturesCXXThis = B; }

bool blockMissingReturnType() const {
  return BlockDeclBits.BlockMissingReturnType;
}

void setBlockMissingReturnType(bool val = true) {
  BlockDeclBits.BlockMissingReturnType = val;
}

bool isConversionFromLambda() const {
  return BlockDeclBits.IsConversionFromLambda;
}

void setIsConversionFromLambda(bool val = true) {
  BlockDeclBits.IsConversionFromLambda = val;
}

bool doesNotEscape() const { return BlockDeclBits.DoesNotEscape; }
void setDoesNotEscape(bool B = true) { BlockDeclBits.DoesNotEscape = B; }

bool canAvoidCopyToHeap() const {
  return BlockDeclBits.CanAvoidCopyToHeap;
}
void setCanAvoidCopyToHeap(bool B = true) {
  BlockDeclBits.CanAvoidCopyToHeap = B;
}

bool capturesVariable(const VarDecl *var) const;

void setCaptures(ASTContext &Context, ArrayRef<Capture> Captures,
                 bool CapturesCXXThis);

unsigned getBlockManglingNumber() const { return ManglingNumber; }

Decl *getBlockManglingContextDecl() const { return ManglingContextDecl; }

void setBlockMangling(unsigned Number, Decl *Ctx) {
  ManglingNumber = Number;
  ManglingContextDecl = Ctx;
}

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Block; }
static DeclContext *castToDeclContext(const BlockDecl *D) {
  return static_cast<DeclContext *>(const_cast<BlockDecl*>(D));
}
static BlockDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<BlockDecl *>(const_cast<DeclContext*>(DC));
}
4329};

4331/// Represents the body of a CapturedStmt, and serves as its DeclContext.
4332class CapturedDecl final
  : public Decl,
    public DeclContext,
    private llvm::TrailingObjects<CapturedDecl, ImplicitParamDecl *> {
4336protected:
size_t numTrailingObjects(OverloadToken<ImplicitParamDecl>) {
  return NumParams;
}

4341private:
/// The number of parameters to the outlined function.
unsigned NumParams;

/// The position of context parameter in list of parameters.
unsigned ContextParam;

/// The body of the outlined function.
llvm::PointerIntPair<Stmt *, 1, bool> BodyAndNothrow;

explicit CapturedDecl(DeclContext *DC, unsigned NumParams);

ImplicitParamDecl *const *getParams() const {
  return getTrailingObjects<ImplicitParamDecl *>();
}

ImplicitParamDecl **getParams() {
  return getTrailingObjects<ImplicitParamDecl *>();
}

4361public:
friend class ASTDeclReader;
friend class ASTDeclWriter;
friend TrailingObjects;

static CapturedDecl *Create(ASTContext &C, DeclContext *DC,
                            unsigned NumParams);
static CapturedDecl *CreateDeserialized(ASTContext &C, unsigned ID,
                                        unsigned NumParams);

Stmt *getBody() const override;
void setBody(Stmt *B);

bool isNothrow() const;
void setNothrow(bool Nothrow = true);

unsigned getNumParams() const { return NumParams; }

ImplicitParamDecl *getParam(unsigned i) const {
  assert(i < NumParams)((void)0);
  return getParams()[i];
}
void setParam(unsigned i, ImplicitParamDecl *P) {
  assert(i < NumParams)((void)0);
  getParams()[i] = P;
}

// ArrayRef interface to parameters.
ArrayRef<ImplicitParamDecl *> parameters() const {
  return {getParams(), getNumParams()};
}
MutableArrayRef<ImplicitParamDecl *> parameters() {
  return {getParams(), getNumParams()};
}

/// Retrieve the parameter containing captured variables.
ImplicitParamDecl *getContextParam() const {
  assert(ContextParam < NumParams)((void)0);
  return getParam(ContextParam);
}
void setContextParam(unsigned i, ImplicitParamDecl *P) {
  assert(i < NumParams)((void)0);
  ContextParam = i;
  setParam(i, P);
}
unsigned getContextParamPosition() const { return ContextParam; }

using param_iterator = ImplicitParamDecl *const *;
using param_range = llvm::iterator_range<param_iterator>;

/// Retrieve an iterator pointing to the first parameter decl.
param_iterator param_begin() const { return getParams(); }
/// Retrieve an iterator one past the last parameter decl.
param_iterator param_end() const { return getParams() + NumParams; }

// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Captured; }
static DeclContext *castToDeclContext(const CapturedDecl *D) {
  return static_cast<DeclContext *>(const_cast<CapturedDecl *>(D));
}
static CapturedDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<CapturedDecl *>(const_cast<DeclContext *>(DC));
}
4425};

4427/// Describes a module import declaration, which makes the contents
4428/// of the named module visible in the current translation unit.
4429///
4430/// An import declaration imports the named module (or submodule). For example:
4431/// \code
4432///   @import std.vector;
4433/// \endcode
4434///
4435/// Import declarations can also be implicitly generated from
4436/// \#include/\#import directives.
4437class ImportDecl final : public Decl,
                       llvm::TrailingObjects<ImportDecl, SourceLocation> {
friend class ASTContext;
friend class ASTDeclReader;
friend class ASTReader;
friend TrailingObjects;

/// The imported module.
Module *ImportedModule = nullptr;

/// The next import in the list of imports local to the translation
/// unit being parsed (not loaded from an AST file).
///
/// Includes a bit that indicates whether we have source-location information
/// for each identifier in the module name.
///
/// When the bit is false, we only have a single source location for the
/// end of the import declaration.
llvm::PointerIntPair<ImportDecl *, 1, bool> NextLocalImportAndComplete;

ImportDecl(DeclContext *DC, SourceLocation StartLoc, Module *Imported,
           ArrayRef<SourceLocation> IdentifierLocs);

ImportDecl(DeclContext *DC, SourceLocation StartLoc, Module *Imported,
           SourceLocation EndLoc);

ImportDecl(EmptyShell Empty) : Decl(Import, Empty) {}

bool isImportComplete() const { return NextLocalImportAndComplete.getInt(); }

void setImportComplete(bool C) { NextLocalImportAndComplete.setInt(C); }

/// The next import in the list of imports local to the translation
/// unit being parsed (not loaded from an AST file).
ImportDecl *getNextLocalImport() const {
  return NextLocalImportAndComplete.getPointer();
}

void setNextLocalImport(ImportDecl *Import) {
  NextLocalImportAndComplete.setPointer(Import);
}

4479public:
/// Create a new module import declaration.
static ImportDecl *Create(ASTContext &C, DeclContext *DC,
                          SourceLocation StartLoc, Module *Imported,
                          ArrayRef<SourceLocation> IdentifierLocs);

/// Create a new module import declaration for an implicitly-generated
/// import.
static ImportDecl *CreateImplicit(ASTContext &C, DeclContext *DC,
                                  SourceLocation StartLoc, Module *Imported,
                                  SourceLocation EndLoc);

/// Create a new, deserialized module import declaration.
static ImportDecl *CreateDeserialized(ASTContext &C, unsigned ID,
                                      unsigned NumLocations);

/// Retrieve the module that was imported by the import declaration.
Module *getImportedModule() const { return ImportedModule; }

/// Retrieves the locations of each of the identifiers that make up
/// the complete module name in the import declaration.
///
/// This will return an empty array if the locations of the individual
/// identifiers aren't available.
ArrayRef<SourceLocation> getIdentifierLocs() const;

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__));

static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Import; }
4509};

4511/// Represents a C++ Modules TS module export declaration.
4512///
4513/// For example:
4514/// \code
4515///   export void foo();
4516/// \endcode
4517class ExportDecl final : public Decl, public DeclContext {
virtual void anchor();

4520private:
friend class ASTDeclReader;

/// The source location for the right brace (if valid).
SourceLocation RBraceLoc;

ExportDecl(DeclContext *DC, SourceLocation ExportLoc)
    : Decl(Export, DC, ExportLoc), DeclContext(Export),
      RBraceLoc(SourceLocation()) {}

4530public:
static ExportDecl *Create(ASTContext &C, DeclContext *DC,
                          SourceLocation ExportLoc);
static ExportDecl *CreateDeserialized(ASTContext &C, unsigned ID);

SourceLocation getExportLoc() const { return getLocation(); }
SourceLocation getRBraceLoc() const { return RBraceLoc; }
void setRBraceLoc(SourceLocation L) { RBraceLoc = L; }

bool hasBraces() const { return RBraceLoc.isValid(); }

SourceLocation getEndLoc() const LLVM_READONLY__attribute__((__pure__)) {
  if (hasBraces())
    return RBraceLoc;
  // No braces: get the end location of the (only) declaration in context
  // (if present).
  return decls_empty() ? getLocation() : decls_begin()->getEndLoc();
}

SourceRange getSourceRange() const override LLVM_READONLY__attribute__((__pure__)) {
  return SourceRange(getLocation(), getEndLoc());
}

static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Export; }
static DeclContext *castToDeclContext(const ExportDecl *D) {
  return static_cast<DeclContext *>(const_cast<ExportDecl*>(D));
}
static ExportDecl *castFromDeclContext(const DeclContext *DC) {
  return static_cast<ExportDecl *>(const_cast<DeclContext*>(DC));
}
4561};

4563/// Represents an empty-declaration.
4564class EmptyDecl : public Decl {
EmptyDecl(DeclContext *DC, SourceLocation L) : Decl(Empty, DC, L) {}

virtual void anchor();

4569public:
static EmptyDecl *Create(ASTContext &C, DeclContext *DC,
                         SourceLocation L);
static EmptyDecl *CreateDeserialized(ASTContext &C, unsigned ID);

static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Empty; }
4576};

4578/// Insertion operator for diagnostics.  This allows sending NamedDecl's
4579/// into a diagnostic with <<.
4580inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &PD,
                                           const NamedDecl *ND) {
PD.AddTaggedVal(reinterpret_cast<intptr_t>(ND),
                DiagnosticsEngine::ak_nameddecl);
return PD;
4585}

4587template<typename decl_type>
4588void Redeclarable<decl_type>::setPreviousDecl(decl_type *PrevDecl) {
// Note: This routine is implemented here because we need both NamedDecl
// and Redeclarable to be defined.
assert(RedeclLink.isFirst() &&((void)0)
       "setPreviousDecl on a decl already in a redeclaration chain")((void)0);

if (PrevDecl) {
  // Point to previous. Make sure that this is actually the most recent
  // redeclaration, or we can build invalid chains. If the most recent
  // redeclaration is invalid, it won't be PrevDecl, but we want it anyway.
  First = PrevDecl->getFirstDecl();
  assert(First->RedeclLink.isFirst() && "Expected first")((void)0);
  decl_type *MostRecent = First->getNextRedeclaration();
  RedeclLink = PreviousDeclLink(cast<decl_type>(MostRecent));

  // If the declaration was previously visible, a redeclaration of it remains
  // visible even if it wouldn't be visible by itself.
  static_cast<decl_type*>(this)->IdentifierNamespace |=
    MostRecent->getIdentifierNamespace() &
    (Decl::IDNS_Ordinary | Decl::IDNS_Tag | Decl::IDNS_Type);
} else {
  // Make this first.
  First = static_cast<decl_type*>(this);
}

// First one will point to this one as latest.
First->RedeclLink.setLatest(static_cast<decl_type*>(this));

assert(!isa<NamedDecl>(static_cast<decl_type*>(this)) ||((void)0)
       cast<NamedDecl>(static_cast<decl_type*>(this))->isLinkageValid())((void)0);
4618}

4620// Inline function definitions.

4622/// Check if the given decl is complete.
4623///
4624/// We use this function to break a cycle between the inline definitions in
4625/// Type.h and Decl.h.
4626inline bool IsEnumDeclComplete(EnumDecl *ED) {
return ED->isComplete();
4628}

4630/// Check if the given decl is scoped.
4631///
4632/// We use this function to break a cycle between the inline definitions in
4633/// Type.h and Decl.h.
4634inline bool IsEnumDeclScoped(EnumDecl *ED) {
return ED->isScoped();
4636}

4638/// OpenMP variants are mangled early based on their OpenMP context selector.
4639/// The new name looks likes this:
4640///  <name> + OpenMPVariantManglingSeparatorStr + <mangled OpenMP context>
4641static constexpr StringRef getOpenMPVariantManglingSeparatorStr() {
return "$ompvariant";
4643}

4645} // namespace clang

4647#endif // LLVM_CLANG_AST_DECL_H

←

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/include/clang/AST/DeclBase.h

→

1//===- DeclBase.h - Base Classes for representing declarations --*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file defines the Decl and DeclContext interfaces.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_CLANG_AST_DECLBASE_H
14#define LLVM_CLANG_AST_DECLBASE_H

16#include "clang/AST/ASTDumperUtils.h"
17#include "clang/AST/AttrIterator.h"
18#include "clang/AST/DeclarationName.h"
19#include "clang/Basic/IdentifierTable.h"
20#include "clang/Basic/LLVM.h"
21#include "clang/Basic/SourceLocation.h"
22#include "clang/Basic/Specifiers.h"
23#include "llvm/ADT/ArrayRef.h"
24#include "llvm/ADT/PointerIntPair.h"
25#include "llvm/ADT/PointerUnion.h"
26#include "llvm/ADT/iterator.h"
27#include "llvm/ADT/iterator_range.h"
28#include "llvm/Support/Casting.h"
29#include "llvm/Support/Compiler.h"
30#include "llvm/Support/PrettyStackTrace.h"
31#include "llvm/Support/VersionTuple.h"
32#include <algorithm>
33#include <cassert>
34#include <cstddef>
35#include <iterator>
36#include <string>
37#include <type_traits>
38#include <utility>

40namespace clang {

42class ASTContext;
43class ASTMutationListener;
44class Attr;
45class BlockDecl;
46class DeclContext;
47class ExternalSourceSymbolAttr;
48class FunctionDecl;
49class FunctionType;
50class IdentifierInfo;
51enum Linkage : unsigned char;
52class LinkageSpecDecl;
53class Module;
54class NamedDecl;
55class ObjCCategoryDecl;
56class ObjCCategoryImplDecl;
57class ObjCContainerDecl;
58class ObjCImplDecl;
59class ObjCImplementationDecl;
60class ObjCInterfaceDecl;
61class ObjCMethodDecl;
62class ObjCProtocolDecl;
63struct PrintingPolicy;
64class RecordDecl;
65class SourceManager;
66class Stmt;
67class StoredDeclsMap;
68class TemplateDecl;
69class TemplateParameterList;
70class TranslationUnitDecl;
71class UsingDirectiveDecl;

73/// Captures the result of checking the availability of a
74/// declaration.
75enum AvailabilityResult {
AR_Available = 0,
AR_NotYetIntroduced,
AR_Deprecated,
AR_Unavailable
80};

82/// Decl - This represents one declaration (or definition), e.g. a variable,
83/// typedef, function, struct, etc.
84///
85/// Note: There are objects tacked on before the *beginning* of Decl
86/// (and its subclasses) in its Decl::operator new(). Proper alignment
87/// of all subclasses (not requiring more than the alignment of Decl) is
88/// asserted in DeclBase.cpp.
89class alignas(8) Decl {
90public:
/// Lists the kind of concrete classes of Decl.
enum Kind {
93#define DECL(DERIVED, BASE) DERIVED,
94#define ABSTRACT_DECL(DECL)
95#define DECL_RANGE(BASE, START, END) \
      first##BASE = START, last##BASE = END,
97#define LAST_DECL_RANGE(BASE, START, END) \
      first##BASE = START, last##BASE = END
99#include "clang/AST/DeclNodes.inc"
};

/// A placeholder type used to construct an empty shell of a
/// decl-derived type that will be filled in later (e.g., by some
/// deserialization method).
struct EmptyShell {};

/// IdentifierNamespace - The different namespaces in which
/// declarations may appear.  According to C99 6.2.3, there are
/// four namespaces, labels, tags, members and ordinary
/// identifiers.  C++ describes lookup completely differently:
/// certain lookups merely "ignore" certain kinds of declarations,
/// usually based on whether the declaration is of a type, etc.
///
/// These are meant as bitmasks, so that searches in
/// C++ can look into the "tag" namespace during ordinary lookup.
///
/// Decl currently provides 15 bits of IDNS bits.
enum IdentifierNamespace {
  /// Labels, declared with 'x:' and referenced with 'goto x'.
  IDNS_Label               = 0x0001,

  /// Tags, declared with 'struct foo;' and referenced with
  /// 'struct foo'.  All tags are also types.  This is what
  /// elaborated-type-specifiers look for in C.
  /// This also contains names that conflict with tags in the
  /// same scope but that are otherwise ordinary names (non-type
  /// template parameters and indirect field declarations).
  IDNS_Tag                 = 0x0002,

  /// Types, declared with 'struct foo', typedefs, etc.
  /// This is what elaborated-type-specifiers look for in C++,
  /// but note that it's ill-formed to find a non-tag.
  IDNS_Type                = 0x0004,

  /// Members, declared with object declarations within tag
  /// definitions.  In C, these can only be found by "qualified"
  /// lookup in member expressions.  In C++, they're found by
  /// normal lookup.
  IDNS_Member              = 0x0008,

  /// Namespaces, declared with 'namespace foo {}'.
  /// Lookup for nested-name-specifiers find these.
  IDNS_Namespace           = 0x0010,

  /// Ordinary names.  In C, everything that's not a label, tag,
  /// member, or function-local extern ends up here.
  IDNS_Ordinary            = 0x0020,

  /// Objective C \@protocol.
  IDNS_ObjCProtocol        = 0x0040,

  /// This declaration is a friend function.  A friend function
  /// declaration is always in this namespace but may also be in
  /// IDNS_Ordinary if it was previously declared.
  IDNS_OrdinaryFriend      = 0x0080,

  /// This declaration is a friend class.  A friend class
  /// declaration is always in this namespace but may also be in
  /// IDNS_Tag|IDNS_Type if it was previously declared.
  IDNS_TagFriend           = 0x0100,

  /// This declaration is a using declaration.  A using declaration
  /// *introduces* a number of other declarations into the current
  /// scope, and those declarations use the IDNS of their targets,
  /// but the actual using declarations go in this namespace.
  IDNS_Using               = 0x0200,

  /// This declaration is a C++ operator declared in a non-class
  /// context.  All such operators are also in IDNS_Ordinary.
  /// C++ lexical operator lookup looks for these.
  IDNS_NonMemberOperator   = 0x0400,

  /// This declaration is a function-local extern declaration of a
  /// variable or function. This may also be IDNS_Ordinary if it
  /// has been declared outside any function. These act mostly like
  /// invisible friend declarations, but are also visible to unqualified
  /// lookup within the scope of the declaring function.
  IDNS_LocalExtern         = 0x0800,

  /// This declaration is an OpenMP user defined reduction construction.
  IDNS_OMPReduction        = 0x1000,

  /// This declaration is an OpenMP user defined mapper.
  IDNS_OMPMapper           = 0x2000,
};

/// ObjCDeclQualifier - 'Qualifiers' written next to the return and
/// parameter types in method declarations.  Other than remembering
/// them and mangling them into the method's signature string, these
/// are ignored by the compiler; they are consumed by certain
/// remote-messaging frameworks.
///
/// in, inout, and out are mutually exclusive and apply only to
/// method parameters.  bycopy and byref are mutually exclusive and
/// apply only to method parameters (?).  oneway applies only to
/// results.  All of these expect their corresponding parameter to
/// have a particular type.  None of this is currently enforced by
/// clang.
///
/// This should be kept in sync with ObjCDeclSpec::ObjCDeclQualifier.
enum ObjCDeclQualifier {
  OBJC_TQ_None = 0x0,
  OBJC_TQ_In = 0x1,
  OBJC_TQ_Inout = 0x2,
  OBJC_TQ_Out = 0x4,
  OBJC_TQ_Bycopy = 0x8,
  OBJC_TQ_Byref = 0x10,
  OBJC_TQ_Oneway = 0x20,

  /// The nullability qualifier is set when the nullability of the
  /// result or parameter was expressed via a context-sensitive
  /// keyword.
  OBJC_TQ_CSNullability = 0x40
};

/// The kind of ownership a declaration has, for visibility purposes.
/// This enumeration is designed such that higher values represent higher
/// levels of name hiding.
enum class ModuleOwnershipKind : unsigned {
  /// This declaration is not owned by a module.
  Unowned,

  /// This declaration has an owning module, but is globally visible
  /// (typically because its owning module is visible and we know that
  /// modules cannot later become hidden in this compilation).
  /// After serialization and deserialization, this will be converted
  /// to VisibleWhenImported.
  Visible,

  /// This declaration has an owning module, and is visible when that
  /// module is imported.
  VisibleWhenImported,

  /// This declaration has an owning module, but is only visible to
  /// lookups that occur within that module.
  ModulePrivate
};

239protected:
/// The next declaration within the same lexical
/// DeclContext. These pointers form the linked list that is
/// traversed via DeclContext's decls_begin()/decls_end().
///
/// The extra two bits are used for the ModuleOwnershipKind.
llvm::PointerIntPair<Decl *, 2, ModuleOwnershipKind> NextInContextAndBits;

247private:
friend class DeclContext;

struct MultipleDC {
  DeclContext *SemanticDC;
  DeclContext *LexicalDC;
};

/// DeclCtx - Holds either a DeclContext* or a MultipleDC*.
/// For declarations that don't contain C++ scope specifiers, it contains
/// the DeclContext where the Decl was declared.
/// For declarations with C++ scope specifiers, it contains a MultipleDC*
/// with the context where it semantically belongs (SemanticDC) and the
/// context where it was lexically declared (LexicalDC).
/// e.g.:
///
///   namespace A {
///      void f(); // SemanticDC == LexicalDC == 'namespace A'
///   }
///   void A::f(); // SemanticDC == namespace 'A'
///                // LexicalDC == global namespace
llvm::PointerUnion<DeclContext*, MultipleDC*> DeclCtx;

bool isInSemaDC() const { return DeclCtx.is<DeclContext*>(); }
bool isOutOfSemaDC() const { return DeclCtx.is<MultipleDC*>(); }

MultipleDC *getMultipleDC() const {
  return DeclCtx.get<MultipleDC*>();
}

DeclContext *getSemanticDC() const {
  return DeclCtx.get<DeclContext*>();
}

/// Loc - The location of this decl.
SourceLocation Loc;

/// DeclKind - This indicates which class this is.
unsigned DeclKind : 7;

/// InvalidDecl - This indicates a semantic error occurred.
unsigned InvalidDecl :  1;

/// HasAttrs - This indicates whether the decl has attributes or not.
unsigned HasAttrs : 1;

/// Implicit - Whether this declaration was implicitly generated by
/// the implementation rather than explicitly written by the user.
unsigned Implicit : 1;

/// Whether this declaration was "used", meaning that a definition is
/// required.
unsigned Used : 1;

/// Whether this declaration was "referenced".
/// The difference with 'Used' is whether the reference appears in a
/// evaluated context or not, e.g. functions used in uninstantiated templates
/// are regarded as "referenced" but not "used".
unsigned Referenced : 1;

/// Whether this declaration is a top-level declaration (function,
/// global variable, etc.) that is lexically inside an objc container
/// definition.
unsigned TopLevelDeclInObjCContainer : 1;

/// Whether statistic collection is enabled.
static bool StatisticsEnabled;

315protected:
friend class ASTDeclReader;
friend class ASTDeclWriter;
friend class ASTNodeImporter;
friend class ASTReader;
friend class CXXClassMemberWrapper;
friend class LinkageComputer;
template<typename decl_type> friend class Redeclarable;

/// Access - Used by C++ decls for the access specifier.
// NOTE: VC++ treats enums as signed, avoid using the AccessSpecifier enum
unsigned Access : 2;

/// Whether this declaration was loaded from an AST file.
unsigned FromASTFile : 1;

/// IdentifierNamespace - This specifies what IDNS_* namespace this lives in.
unsigned IdentifierNamespace : 14;

/// If 0, we have not computed the linkage of this declaration.
/// Otherwise, it is the linkage + 1.
mutable unsigned CacheValidAndLinkage : 3;

/// Allocate memory for a deserialized declaration.
///
/// This routine must be used to allocate memory for any declaration that is
/// deserialized from a module file.
///
/// \param Size The size of the allocated object.
/// \param Ctx The context in which we will allocate memory.
/// \param ID The global ID of the deserialized declaration.
/// \param Extra The amount of extra space to allocate after the object.
void *operator new(std::size_t Size, const ASTContext &Ctx, unsigned ID,
                   std::size_t Extra = 0);

/// Allocate memory for a non-deserialized declaration.
void *operator new(std::size_t Size, const ASTContext &Ctx,
                   DeclContext *Parent, std::size_t Extra = 0);

354private:
bool AccessDeclContextSanity() const;

/// Get the module ownership kind to use for a local lexical child of \p DC,
/// which may be either a local or (rarely) an imported declaration.
static ModuleOwnershipKind getModuleOwnershipKindForChildOf(DeclContext *DC) {
  if (DC) {
    auto *D = cast<Decl>(DC);
    auto MOK = D->getModuleOwnershipKind();
    if (MOK != ModuleOwnershipKind::Unowned &&
        (!D->isFromASTFile() || D->hasLocalOwningModuleStorage()))
      return MOK;
    // If D is not local and we have no local module storage, then we don't
    // need to track module ownership at all.
  }
  return ModuleOwnershipKind::Unowned;
}

372public:
Decl() = delete;
Decl(const Decl&) = delete;
Decl(Decl &&) = delete;
Decl &operator=(const Decl&) = delete;
Decl &operator=(Decl&&) = delete;

379protected:
Decl(Kind DK, DeclContext *DC, SourceLocation L)
    : NextInContextAndBits(nullptr, getModuleOwnershipKindForChildOf(DC)),
      DeclCtx(DC), Loc(L), DeclKind(DK), InvalidDecl(false), HasAttrs(false),
      Implicit(false), Used(false), Referenced(false),
      TopLevelDeclInObjCContainer(false), Access(AS_none), FromASTFile(0),
      IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
      CacheValidAndLinkage(0) {
  if (StatisticsEnabled) add(DK);
}

Decl(Kind DK, EmptyShell Empty)
    : DeclKind(DK), InvalidDecl(false), HasAttrs(false), Implicit(false),
      Used(false), Referenced(false), TopLevelDeclInObjCContainer(false),
      Access(AS_none), FromASTFile(0),
      IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
      CacheValidAndLinkage(0) {
  if (StatisticsEnabled) add(DK);
}

virtual ~Decl();

/// Update a potentially out-of-date declaration.
void updateOutOfDate(IdentifierInfo &II) const;

Linkage getCachedLinkage() const {
  return Linkage(CacheValidAndLinkage - 1);
}

void setCachedLinkage(Linkage L) const {
  CacheValidAndLinkage = L + 1;
}

bool hasCachedLinkage() const {
  return CacheValidAndLinkage;
}

416public:
/// Source range that this declaration covers.
virtual SourceRange getSourceRange() const LLVM_READONLY__attribute__((__pure__)) {
  return SourceRange(getLocation(), getLocation());
}

SourceLocation getBeginLoc() const LLVM_READONLY__attribute__((__pure__)) {
  return getSourceRange().getBegin();
}

SourceLocation getEndLoc() const LLVM_READONLY__attribute__((__pure__)) {
  return getSourceRange().getEnd();
}

SourceLocation getLocation() const { return Loc; }
void setLocation(SourceLocation L) { Loc = L; }

Kind getKind() const { return static_cast<Kind>(DeclKind); }
const char *getDeclKindName() const;

Decl *getNextDeclInContext() { return NextInContextAndBits.getPointer(); }
const Decl *getNextDeclInContext() const {return NextInContextAndBits.getPointer();}

DeclContext *getDeclContext() {
  if (isInSemaDC())
    return getSemanticDC();
  return getMultipleDC()->SemanticDC;
}
const DeclContext *getDeclContext() const {
  return const_cast<Decl*>(this)->getDeclContext();
}

/// Find the innermost non-closure ancestor of this declaration,
/// walking up through blocks, lambdas, etc.  If that ancestor is
/// not a code context (!isFunctionOrMethod()), returns null.
///
/// A declaration may be its own non-closure context.
Decl *getNonClosureContext();
const Decl *getNonClosureContext() const {
  return const_cast<Decl*>(this)->getNonClosureContext();
}

TranslationUnitDecl *getTranslationUnitDecl();
const TranslationUnitDecl *getTranslationUnitDecl() const {
  return const_cast<Decl*>(this)->getTranslationUnitDecl();
}

bool isInAnonymousNamespace() const;

bool isInStdNamespace() const;

ASTContext &getASTContext() const LLVM_READONLY__attribute__((__pure__));

/// Helper to get the language options from the ASTContext.
/// Defined out of line to avoid depending on ASTContext.h.
const LangOptions &getLangOpts() const LLVM_READONLY__attribute__((__pure__));

void setAccess(AccessSpecifier AS) {
  Access = AS;
  assert(AccessDeclContextSanity())((void)0);
}

AccessSpecifier getAccess() const {
  assert(AccessDeclContextSanity())((void)0);
  return AccessSpecifier(Access);
}

/// Retrieve the access specifier for this declaration, even though
/// it may not yet have been properly set.
AccessSpecifier getAccessUnsafe() const {
  return AccessSpecifier(Access);
}

bool hasAttrs() const { return HasAttrs; }

void setAttrs(const AttrVec& Attrs) {
  return setAttrsImpl(Attrs, getASTContext());
}

AttrVec &getAttrs() {
  return const_cast<AttrVec&>(const_cast<const Decl*>(this)->getAttrs());
}

const AttrVec &getAttrs() const;
void dropAttrs();
void addAttr(Attr *A);

using attr_iterator = AttrVec::const_iterator;
using attr_range = llvm::iterator_range<attr_iterator>;

attr_range attrs() const {
  return attr_range(attr_begin(), attr_end());
}

attr_iterator attr_begin() const {
  return hasAttrs() ? getAttrs().begin() : nullptr;
}
attr_iterator attr_end() const {
  return hasAttrs() ? getAttrs().end() : nullptr;
}

template <typename T>
void dropAttr() {
  if (!HasAttrs) return;

  AttrVec &Vec = getAttrs();
  llvm::erase_if(Vec, [](Attr *A) { return isa<T>(A); });

  if (Vec.empty())
    HasAttrs = false;
}

template <typename T>
llvm::iterator_range<specific_attr_iterator<T>> specific_attrs() const {
  return llvm::make_range(specific_attr_begin<T>(), specific_attr_end<T>());
}

template <typename T>
specific_attr_iterator<T> specific_attr_begin() const {
  return specific_attr_iterator<T>(attr_begin());
}

template <typename T>
specific_attr_iterator<T> specific_attr_end() const {
  return specific_attr_iterator<T>(attr_end());
}

template<typename T> T *getAttr() const {
  return hasAttrs() ? getSpecificAttr<T>(getAttrs()) : nullptr;
}

template<typename T> bool hasAttr() const {
  return hasAttrs() && hasSpecificAttr<T>(getAttrs());
}

/// getMaxAlignment - return the maximum alignment specified by attributes
/// on this decl, 0 if there are none.
unsigned getMaxAlignment() const;

/// setInvalidDecl - Indicates the Decl had a semantic error. This
/// allows for graceful error recovery.
void setInvalidDecl(bool Invalid = true);
bool isInvalidDecl() const { return (bool) InvalidDecl; }

/// isImplicit - Indicates whether the declaration was implicitly
/// generated by the implementation. If false, this declaration
/// was written explicitly in the source code.
bool isImplicit() const { return Implicit; }
void setImplicit(bool I = true) { Implicit = I; }

/// Whether *any* (re-)declaration of the entity was used, meaning that
/// a definition is required.
///
/// \param CheckUsedAttr When true, also consider the "used" attribute
/// (in addition to the "used" bit set by \c setUsed()) when determining
/// whether the function is used.
bool isUsed(bool CheckUsedAttr = true) const;

/// Set whether the declaration is used, in the sense of odr-use.
///
/// This should only be used immediately after creating a declaration.
/// It intentionally doesn't notify any listeners.
void setIsUsed() { getCanonicalDecl()->Used = true; }

/// Mark the declaration used, in the sense of odr-use.
///
/// This notifies any mutation listeners in addition to setting a bit
/// indicating the declaration is used.
void markUsed(ASTContext &C);

/// Whether any declaration of this entity was referenced.
bool isReferenced() const;

/// Whether this declaration was referenced. This should not be relied
/// upon for anything other than debugging.
bool isThisDeclarationReferenced() const { return Referenced; }

void setReferenced(bool R = true) { Referenced = R; }

/// Whether this declaration is a top-level declaration (function,
/// global variable, etc.) that is lexically inside an objc container
/// definition.
bool isTopLevelDeclInObjCContainer() const {
  return TopLevelDeclInObjCContainer;
}

void setTopLevelDeclInObjCContainer(bool V = true) {
  TopLevelDeclInObjCContainer = V;
}

/// Looks on this and related declarations for an applicable
/// external source symbol attribute.
ExternalSourceSymbolAttr *getExternalSourceSymbolAttr() const;

/// Whether this declaration was marked as being private to the
/// module in which it was defined.
bool isModulePrivate() const {
  return getModuleOwnershipKind() == ModuleOwnershipKind::ModulePrivate;
}

/// Return true if this declaration has an attribute which acts as
/// definition of the entity, such as 'alias' or 'ifunc'.
bool hasDefiningAttr() const;

/// Return this declaration's defining attribute if it has one.
const Attr *getDefiningAttr() const;

623protected:
/// Specify that this declaration was marked as being private
/// to the module in which it was defined.
void setModulePrivate() {
  // The module-private specifier has no effect on unowned declarations.
  // FIXME: We should track this in some way for source fidelity.
  if (getModuleOwnershipKind() == ModuleOwnershipKind::Unowned)
    return;
  setModuleOwnershipKind(ModuleOwnershipKind::ModulePrivate);
}

634public:
/// Set the FromASTFile flag. This indicates that this declaration
/// was deserialized and not parsed from source code and enables
/// features such as module ownership information.
void setFromASTFile() {
  FromASTFile = true;
}

/// Set the owning module ID.  This may only be called for
/// deserialized Decls.
void setOwningModuleID(unsigned ID) {
  assert(isFromASTFile() && "Only works on a deserialized declaration")((void)0);
  *((unsigned*)this - 2) = ID;
}

649public:
/// Determine the availability of the given declaration.
///
/// This routine will determine the most restrictive availability of
/// the given declaration (e.g., preferring 'unavailable' to
/// 'deprecated').
///
/// \param Message If non-NULL and the result is not \c
/// AR_Available, will be set to a (possibly empty) message
/// describing why the declaration has not been introduced, is
/// deprecated, or is unavailable.
///
/// \param EnclosingVersion The version to compare with. If empty, assume the
/// deployment target version.
///
/// \param RealizedPlatform If non-NULL and the availability result is found
/// in an available attribute it will set to the platform which is written in
/// the available attribute.
AvailabilityResult
getAvailability(std::string *Message = nullptr,
                VersionTuple EnclosingVersion = VersionTuple(),
                StringRef *RealizedPlatform = nullptr) const;

/// Retrieve the version of the target platform in which this
/// declaration was introduced.
///
/// \returns An empty version tuple if this declaration has no 'introduced'
/// availability attributes, or the version tuple that's specified in the
/// attribute otherwise.
VersionTuple getVersionIntroduced() const;

/// Determine whether this declaration is marked 'deprecated'.
///
/// \param Message If non-NULL and the declaration is deprecated,
/// this will be set to the message describing why the declaration
/// was deprecated (which may be empty).
bool isDeprecated(std::string *Message = nullptr) const {
  return getAvailability(Message) == AR_Deprecated;
}

/// Determine whether this declaration is marked 'unavailable'.
///
/// \param Message If non-NULL and the declaration is unavailable,
/// this will be set to the message describing why the declaration
/// was made unavailable (which may be empty).
bool isUnavailable(std::string *Message = nullptr) const {
  return getAvailability(Message) == AR_Unavailable;
}

/// Determine whether this is a weak-imported symbol.
///
/// Weak-imported symbols are typically marked with the
/// 'weak_import' attribute, but may also be marked with an
/// 'availability' attribute where we're targing a platform prior to
/// the introduction of this feature.
bool isWeakImported() const;

/// Determines whether this symbol can be weak-imported,
/// e.g., whether it would be well-formed to add the weak_import
/// attribute.
///
/// \param IsDefinition Set to \c true to indicate that this
/// declaration cannot be weak-imported because it has a definition.
bool canBeWeakImported(bool &IsDefinition) const;

/// Determine whether this declaration came from an AST file (such as
/// a precompiled header or module) rather than having been parsed.
bool isFromASTFile() const { return FromASTFile; }

/// Retrieve the global declaration ID associated with this
/// declaration, which specifies where this Decl was loaded from.
unsigned getGlobalID() const {
  if (isFromASTFile())
    return *((const unsigned*)this - 1);
  return 0;
}

/// Retrieve the global ID of the module that owns this particular
/// declaration.
unsigned getOwningModuleID() const {
  if (isFromASTFile())
    return *((const unsigned*)this - 2);
  return 0;
}

734private:
Module *getOwningModuleSlow() const;

737protected:
bool hasLocalOwningModuleStorage() const;

740public:
/// Get the imported owning module, if this decl is from an imported
/// (non-local) module.
Module *getImportedOwningModule() const {
  if (!isFromASTFile() || !hasOwningModule())
    return nullptr;

  return getOwningModuleSlow();
}

/// Get the local owning module, if known. Returns nullptr if owner is
/// not yet known or declaration is not from a module.
Module *getLocalOwningModule() const {
  if (isFromASTFile() || !hasOwningModule())
    return nullptr;

  assert(hasLocalOwningModuleStorage() &&((void)0)
         "owned local decl but no local module storage")((void)0);
  return reinterpret_cast<Module *const *>(this)[-1];
}
void setLocalOwningModule(Module *M) {
  assert(!isFromASTFile() && hasOwningModule() &&((void)0)
         hasLocalOwningModuleStorage() &&((void)0)
         "should not have a cached owning module")((void)0);
  reinterpret_cast<Module **>(this)[-1] = M;
}

/// Is this declaration owned by some module?
bool hasOwningModule() const {
  return getModuleOwnershipKind() != ModuleOwnershipKind::Unowned;
}

/// Get the module that owns this declaration (for visibility purposes).
Module *getOwningModule() const {
  return isFromASTFile() ? getImportedOwningModule() : getLocalOwningModule();
}

/// Get the module that owns this declaration for linkage purposes.
/// There only ever is such a module under the C++ Modules TS.
///
/// \param IgnoreLinkage Ignore the linkage of the entity; assume that
/// all declarations in a global module fragment are unowned.
Module *getOwningModuleForLinkage(bool IgnoreLinkage = false) const;

/// Determine whether this declaration is definitely visible to name lookup,
/// independent of whether the owning module is visible.
/// Note: The declaration may be visible even if this returns \c false if the
/// owning module is visible within the query context. This is a low-level
/// helper function; most code should be calling Sema::isVisible() instead.
bool isUnconditionallyVisible() const {
  return (int)getModuleOwnershipKind() <= (int)ModuleOwnershipKind::Visible;
}

/// Set that this declaration is globally visible, even if it came from a
/// module that is not visible.
void setVisibleDespiteOwningModule() {
  if (!isUnconditionallyVisible())
    setModuleOwnershipKind(ModuleOwnershipKind::Visible);
}

/// Get the kind of module ownership for this declaration.
ModuleOwnershipKind getModuleOwnershipKind() const {
  return NextInContextAndBits.getInt();
}

/// Set whether this declaration is hidden from name lookup.
void setModuleOwnershipKind(ModuleOwnershipKind MOK) {
  assert(!(getModuleOwnershipKind() == ModuleOwnershipKind::Unowned &&((void)0)
           MOK != ModuleOwnershipKind::Unowned && !isFromASTFile() &&((void)0)
           !hasLocalOwningModuleStorage()) &&((void)0)
         "no storage available for owning module for this declaration")((void)0);
  NextInContextAndBits.setInt(MOK);
}

unsigned getIdentifierNamespace() const {
  return IdentifierNamespace;
}

bool isInIdentifierNamespace(unsigned NS) const {
  return getIdentifierNamespace() & NS;
}

static unsigned getIdentifierNamespaceForKind(Kind DK);

bool hasTagIdentifierNamespace() const {
  return isTagIdentifierNamespace(getIdentifierNamespace());
}

static bool isTagIdentifierNamespace(unsigned NS) {
  // TagDecls have Tag and Type set and may also have TagFriend.
  return (NS & ~IDNS_TagFriend) == (IDNS_Tag | IDNS_Type);
}

/// getLexicalDeclContext - The declaration context where this Decl was
/// lexically declared (LexicalDC). May be different from
/// getDeclContext() (SemanticDC).
/// e.g.:
///
///   namespace A {
///      void f(); // SemanticDC == LexicalDC == 'namespace A'
///   }
///   void A::f(); // SemanticDC == namespace 'A'
///                // LexicalDC == global namespace
DeclContext *getLexicalDeclContext() {
  if (isInSemaDC())
    return getSemanticDC();
  return getMultipleDC()->LexicalDC;
}
const DeclContext *getLexicalDeclContext() const {
  return const_cast<Decl*>(this)->getLexicalDeclContext();
}

/// Determine whether this declaration is declared out of line (outside its
/// semantic context).
virtual bool isOutOfLine() const;

/// setDeclContext - Set both the semantic and lexical DeclContext
/// to DC.
void setDeclContext(DeclContext *DC);

void setLexicalDeclContext(DeclContext *DC);

/// Determine whether this declaration is a templated entity (whether it is
// within the scope of a template parameter).
bool isTemplated() const;

/// Determine the number of levels of template parameter surrounding this
/// declaration.
unsigned getTemplateDepth() const;

/// isDefinedOutsideFunctionOrMethod - This predicate returns true if this
/// scoped decl is defined outside the current function or method.  This is
/// roughly global variables and functions, but also handles enums (which
/// could be defined inside or outside a function etc).
bool isDefinedOutsideFunctionOrMethod() const {
  return getParentFunctionOrMethod() == nullptr;
}

/// Determine whether a substitution into this declaration would occur as
/// part of a substitution into a dependent local scope. Such a substitution
/// transitively substitutes into all constructs nested within this
/// declaration.
///
/// This recognizes non-defining declarations as well as members of local
/// classes and lambdas:
/// \code
///     template<typename T> void foo() { void bar(); }
///     template<typename T> void foo2() { class ABC { void bar(); }; }
///     template<typename T> inline int x = [](){ return 0; }();
/// \endcode
bool isInLocalScopeForInstantiation() const;

/// If this decl is defined inside a function/method/block it returns
/// the corresponding DeclContext, otherwise it returns null.
const DeclContext *getParentFunctionOrMethod() const;
DeclContext *getParentFunctionOrMethod() {
  return const_cast<DeclContext*>(
                  const_cast<const Decl*>(this)->getParentFunctionOrMethod());
}

/// Retrieves the "canonical" declaration of the given declaration.
virtual Decl *getCanonicalDecl() { return this; }
const Decl *getCanonicalDecl() const {
  return const_cast<Decl*>(this)->getCanonicalDecl();
}

/// Whether this particular Decl is a canonical one.
bool isCanonicalDecl() const { return getCanonicalDecl() == this; }

909protected:
/// Returns the next redeclaration or itself if this is the only decl.
///
/// Decl subclasses that can be redeclared should override this method so that
/// Decl::redecl_iterator can iterate over them.
virtual Decl *getNextRedeclarationImpl() { return this; }

/// Implementation of getPreviousDecl(), to be overridden by any
/// subclass that has a redeclaration chain.
virtual Decl *getPreviousDeclImpl() { return nullptr; }

/// Implementation of getMostRecentDecl(), to be overridden by any
/// subclass that has a redeclaration chain.
virtual Decl *getMostRecentDeclImpl() { return this; }

924public:
/// Iterates through all the redeclarations of the same decl.
class redecl_iterator {
  /// Current - The current declaration.
  Decl *Current = nullptr;
  Decl *Starter;

public:
  using value_type = Decl *;
  using reference = const value_type &;
  using pointer = const value_type *;
  using iterator_category = std::forward_iterator_tag;
  using difference_type = std::ptrdiff_t;

  redecl_iterator() = default;
  explicit redecl_iterator(Decl *C) : Current(C), Starter(C) {}

  reference operator*() const { return Current; }
  value_type operator->() const { return Current; }

  redecl_iterator& operator++() {
    assert(Current && "Advancing while iterator has reached end")((void)0);
    // Get either previous decl or latest decl.
    Decl *Next = Current->getNextRedeclarationImpl();
    assert(Next && "Should return next redeclaration or itself, never null!")((void)0);
    Current = (Next != Starter) ? Next : nullptr;
    return *this;
  }

  redecl_iterator operator++(int) {
    redecl_iterator tmp(*this);
    ++(*this);
    return tmp;
  }

  friend bool operator==(redecl_iterator x, redecl_iterator y) {
    return x.Current == y.Current;
  }

  friend bool operator!=(redecl_iterator x, redecl_iterator y) {
    return x.Current != y.Current;
  }
};

using redecl_range = llvm::iterator_range<redecl_iterator>;

/// Returns an iterator range for all the redeclarations of the same
/// decl. It will iterate at least once (when this decl is the only one).
redecl_range redecls() const {
  return redecl_range(redecls_begin(), redecls_end());
}

redecl_iterator redecls_begin() const {
  return redecl_iterator(const_cast<Decl *>(this));
}

redecl_iterator redecls_end() const { return redecl_iterator(); }

/// Retrieve the previous declaration that declares the same entity
/// as this declaration, or NULL if there is no previous declaration.
Decl *getPreviousDecl() { return getPreviousDeclImpl(); }

/// Retrieve the previous declaration that declares the same entity
/// as this declaration, or NULL if there is no previous declaration.
const Decl *getPreviousDecl() const {
  return const_cast<Decl *>(this)->getPreviousDeclImpl();
}

/// True if this is the first declaration in its redeclaration chain.
bool isFirstDecl() const {
  return getPreviousDecl() == nullptr;
}

/// Retrieve the most recent declaration that declares the same entity
/// as this declaration (which may be this declaration).
Decl *getMostRecentDecl() { return getMostRecentDeclImpl(); }

/// Retrieve the most recent declaration that declares the same entity
/// as this declaration (which may be this declaration).
const Decl *getMostRecentDecl() const {
  return const_cast<Decl *>(this)->getMostRecentDeclImpl();
}

/// getBody - If this Decl represents a declaration for a body of code,
///  such as a function or method definition, this method returns the
///  top-level Stmt* of that body.  Otherwise this method returns null.
virtual Stmt* getBody() const { return nullptr; }

/// Returns true if this \c Decl represents a declaration for a body of
/// code, such as a function or method definition.
/// Note that \c hasBody can also return true if any redeclaration of this
/// \c Decl represents a declaration for a body of code.
virtual bool hasBody() const { return getBody() != nullptr; }

/// getBodyRBrace - Gets the right brace of the body, if a body exists.
/// This works whether the body is a CompoundStmt or a CXXTryStmt.
SourceLocation getBodyRBrace() const;

// global temp stats (until we have a per-module visitor)
static void add(Kind k);
static void EnableStatistics();
static void PrintStats();

/// isTemplateParameter - Determines whether this declaration is a
/// template parameter.
bool isTemplateParameter() const;

/// isTemplateParameter - Determines whether this declaration is a
/// template parameter pack.
bool isTemplateParameterPack() const;

/// Whether this declaration is a parameter pack.
bool isParameterPack() const;

/// returns true if this declaration is a template
bool isTemplateDecl() const;

/// Whether this declaration is a function or function template.
bool isFunctionOrFunctionTemplate() const {
  return (DeclKind >= Decl::firstFunction &&
          DeclKind <= Decl::lastFunction) ||
         DeclKind == FunctionTemplate;
}

/// If this is a declaration that describes some template, this
/// method returns that template declaration.
///
/// Note that this returns nullptr for partial specializations, because they
/// are not modeled as TemplateDecls. Use getDescribedTemplateParams to handle
/// those cases.
TemplateDecl *getDescribedTemplate() const;

/// If this is a declaration that describes some template or partial
/// specialization, this returns the corresponding template parameter list.
const TemplateParameterList *getDescribedTemplateParams() const;

/// Returns the function itself, or the templated function if this is a
/// function template.
FunctionDecl *getAsFunction() LLVM_READONLY__attribute__((__pure__));

const FunctionDecl *getAsFunction() const {
  return const_cast<Decl *>(this)->getAsFunction();
}

/// Changes the namespace of this declaration to reflect that it's
/// a function-local extern declaration.
///
/// These declarations appear in the lexical context of the extern
/// declaration, but in the semantic context of the enclosing namespace
/// scope.
void setLocalExternDecl() {
  Decl *Prev = getPreviousDecl();
  IdentifierNamespace &= ~IDNS_Ordinary;

  // It's OK for the declaration to still have the "invisible friend" flag or
  // the "conflicts with tag declarations in this scope" flag for the outer
  // scope.
  assert((IdentifierNamespace & ~(IDNS_OrdinaryFriend | IDNS_Tag)) == 0 &&((void)0)
         "namespace is not ordinary")((void)0);

  IdentifierNamespace |= IDNS_LocalExtern;
  if (Prev && Prev->getIdentifierNamespace() & IDNS_Ordinary)
    IdentifierNamespace |= IDNS_Ordinary;
}

/// Determine whether this is a block-scope declaration with linkage.
/// This will either be a local variable declaration declared 'extern', or a
/// local function declaration.
bool isLocalExternDecl() {
  return IdentifierNamespace & IDNS_LocalExtern;
}

/// Changes the namespace of this declaration to reflect that it's
/// the object of a friend declaration.
///
/// These declarations appear in the lexical context of the friending
/// class, but in the semantic context of the actual entity.  This property
/// applies only to a specific decl object;  other redeclarations of the
/// same entity may not (and probably don't) share this property.
void setObjectOfFriendDecl(bool PerformFriendInjection = false) {
  unsigned OldNS = IdentifierNamespace;
  assert((OldNS & (IDNS_Tag | IDNS_Ordinary |((void)0)
                   IDNS_TagFriend | IDNS_OrdinaryFriend |((void)0)
                   IDNS_LocalExtern | IDNS_NonMemberOperator)) &&((void)0)
         "namespace includes neither ordinary nor tag")((void)0);
  assert(!(OldNS & ~(IDNS_Tag | IDNS_Ordinary | IDNS_Type |((void)0)
                     IDNS_TagFriend | IDNS_OrdinaryFriend |((void)0)
                     IDNS_LocalExtern | IDNS_NonMemberOperator)) &&((void)0)
         "namespace includes other than ordinary or tag")((void)0);

  Decl *Prev = getPreviousDecl();
  IdentifierNamespace &= ~(IDNS_Ordinary | IDNS_Tag | IDNS_Type);

  if (OldNS & (IDNS_Tag | IDNS_TagFriend)) {
    IdentifierNamespace |= IDNS_TagFriend;
    if (PerformFriendInjection ||
        (Prev && Prev->getIdentifierNamespace() & IDNS_Tag))
      IdentifierNamespace |= IDNS_Tag | IDNS_Type;
  }

  if (OldNS & (IDNS_Ordinary | IDNS_OrdinaryFriend |
               IDNS_LocalExtern | IDNS_NonMemberOperator)) {
    IdentifierNamespace |= IDNS_OrdinaryFriend;
    if (PerformFriendInjection ||
        (Prev && Prev->getIdentifierNamespace() & IDNS_Ordinary))
      IdentifierNamespace |= IDNS_Ordinary;
  }
}

enum FriendObjectKind {
  FOK_None,      ///< Not a friend object.
  FOK_Declared,  ///< A friend of a previously-declared entity.
  FOK_Undeclared ///< A friend of a previously-undeclared entity.
};

/// Determines whether this declaration is the object of a
/// friend declaration and, if so, what kind.
///
/// There is currently no direct way to find the associated FriendDecl.
FriendObjectKind getFriendObjectKind() const {
  unsigned mask =
      (IdentifierNamespace & (IDNS_TagFriend | IDNS_OrdinaryFriend));
  if (!mask) return FOK_None;
  return (IdentifierNamespace & (IDNS_Tag | IDNS_Ordinary) ? FOK_Declared
                                                           : FOK_Undeclared);
}

/// Specifies that this declaration is a C++ overloaded non-member.
void setNonMemberOperator() {
  assert(getKind() == Function || getKind() == FunctionTemplate)((void)0);
  assert((IdentifierNamespace & IDNS_Ordinary) &&((void)0)
         "visible non-member operators should be in ordinary namespace")((void)0);
  IdentifierNamespace |= IDNS_NonMemberOperator;
}

static bool classofKind(Kind K) { return true; }
static DeclContext *castToDeclContext(const Decl *);
static Decl *castFromDeclContext(const DeclContext *);

void print(raw_ostream &Out, unsigned Indentation = 0,
           bool PrintInstantiation = false) const;
void print(raw_ostream &Out, const PrintingPolicy &Policy,
           unsigned Indentation = 0, bool PrintInstantiation = false) const;
static void printGroup(Decl** Begin, unsigned NumDecls,
                       raw_ostream &Out, const PrintingPolicy &Policy,
                       unsigned Indentation = 0);

// Debuggers don't usually respect default arguments.
void dump() const;

// Same as dump(), but forces color printing.
void dumpColor() const;

void dump(raw_ostream &Out, bool Deserialize = false,
          ASTDumpOutputFormat OutputFormat = ADOF_Default) const;

/// \return Unique reproducible object identifier
int64_t getID() const;

/// Looks through the Decl's underlying type to extract a FunctionType
/// when possible. Will return null if the type underlying the Decl does not
/// have a FunctionType.
const FunctionType *getFunctionType(bool BlocksToo = true) const;

1188private:
void setAttrsImpl(const AttrVec& Attrs, ASTContext &Ctx);
void setDeclContextsImpl(DeclContext *SemaDC, DeclContext *LexicalDC,
                         ASTContext &Ctx);

1193protected:
ASTMutationListener *getASTMutationListener() const;
1195};

1197/// Determine whether two declarations declare the same entity.
1198inline bool declaresSameEntity(const Decl *D1, const Decl *D2) {
if (!D1 || !D2)
  return false;

if (D1 == D2)
  return true;

return D1->getCanonicalDecl() == D2->getCanonicalDecl();
1206}

1208/// PrettyStackTraceDecl - If a crash occurs, indicate that it happened when
1209/// doing something to a specific decl.
1210class PrettyStackTraceDecl : public llvm::PrettyStackTraceEntry {
const Decl *TheDecl;
SourceLocation Loc;
SourceManager &SM;
const char *Message;

1216public:
PrettyStackTraceDecl(const Decl *theDecl, SourceLocation L,
                     SourceManager &sm, const char *Msg)
    : TheDecl(theDecl), Loc(L), SM(sm), Message(Msg) {}

void print(raw_ostream &OS) const override;
1222};
1223} // namespace clang

1225// Required to determine the layout of the PointerUnion<NamedDecl*> before
1226// seeing the NamedDecl definition being first used in DeclListNode::operator*.
1227namespace llvm {
template <> struct PointerLikeTypeTraits<::clang::NamedDecl *> {
  static inline void *getAsVoidPointer(::clang::NamedDecl *P) { return P; }
  static inline ::clang::NamedDecl *getFromVoidPointer(void *P) {
    return static_cast<::clang::NamedDecl *>(P);
  }
  static constexpr int NumLowBitsAvailable = 3;
};
1235}

1237namespace clang {
1238/// A list storing NamedDecls in the lookup tables.
1239class DeclListNode {
friend class ASTContext; // allocate, deallocate nodes.
friend class StoredDeclsList;
1242public:
using Decls = llvm::PointerUnion<NamedDecl*, DeclListNode*>;
class iterator {
  friend class DeclContextLookupResult;
  friend class StoredDeclsList;

  Decls Ptr;
  iterator(Decls Node) : Ptr(Node) { }
public:
  using difference_type = ptrdiff_t;
  using value_type = NamedDecl*;
  using pointer = void;
  using reference = value_type;
  using iterator_category = std::forward_iterator_tag;

  iterator() = default;

  reference operator*() const {
    assert(Ptr && "dereferencing end() iterator")((void)0);
    if (DeclListNode *CurNode = Ptr.dyn_cast<DeclListNode*>())
      return CurNode->D;
    return Ptr.get<NamedDecl*>();
  }
  void operator->() const { } // Unsupported.
  bool operator==(const iterator &X) const { return Ptr == X.Ptr; }
  bool operator!=(const iterator &X) const { return Ptr != X.Ptr; }
  inline iterator &operator++() { // ++It
    assert(!Ptr.isNull() && "Advancing empty iterator")((void)0);

    if (DeclListNode *CurNode = Ptr.dyn_cast<DeclListNode*>())
      Ptr = CurNode->Rest;
    else
      Ptr = nullptr;
    return *this;
  }
  iterator operator++(int) { // It++
    iterator temp = *this;
    ++(*this);
    return temp;
  }
  // Enables the pattern for (iterator I =..., E = I.end(); I != E; ++I)
  iterator end() { return iterator(); }
};
1285private:
NamedDecl *D = nullptr;
Decls Rest = nullptr;
DeclListNode(NamedDecl *ND) : D(ND) {}
1289};

1291/// The results of name lookup within a DeclContext.
1292class DeclContextLookupResult {
using Decls = DeclListNode::Decls;

/// When in collection form, this is what the Data pointer points to.
Decls Result;

1298public:
DeclContextLookupResult() = default;
DeclContextLookupResult(Decls Result) : Result(Result) {}

using iterator = DeclListNode::iterator;
using const_iterator = iterator;
using reference = iterator::reference;

iterator begin() { return iterator(Result); }
iterator end() { return iterator(); }
const_iterator begin() const {
  return const_cast<DeclContextLookupResult*>(this)->begin();
}
const_iterator end() const { return iterator(); }

bool empty() const { return Result.isNull();  }
bool isSingleResult() const { return Result.dyn_cast<NamedDecl*>(); }
reference front() const { return *begin(); }

// Find the first declaration of the given type in the list. Note that this
// is not in general the earliest-declared declaration, and should only be
// used when it's not possible for there to be more than one match or where
// it doesn't matter which one is found.
template<class T> T *find_first() const {
  for (auto *D : *this)
    if (T *Decl = dyn_cast<T>(D))
      return Decl;

  return nullptr;
}
1328};

1330/// DeclContext - This is used only as base class of specific decl types that
1331/// can act as declaration contexts. These decls are (only the top classes
1332/// that directly derive from DeclContext are mentioned, not their subclasses):
1333///
1334///   TranslationUnitDecl
1335///   ExternCContext
1336///   NamespaceDecl
1337///   TagDecl
1338///   OMPDeclareReductionDecl
1339///   OMPDeclareMapperDecl
1340///   FunctionDecl
1341///   ObjCMethodDecl
1342///   ObjCContainerDecl
1343///   LinkageSpecDecl
1344///   ExportDecl
1345///   BlockDecl
1346///   CapturedDecl
1347class DeclContext {
/// For makeDeclVisibleInContextImpl
friend class ASTDeclReader;
/// For reconcileExternalVisibleStorage, CreateStoredDeclsMap,
/// hasNeedToReconcileExternalVisibleStorage
friend class ExternalASTSource;
/// For CreateStoredDeclsMap
friend class DependentDiagnostic;
/// For hasNeedToReconcileExternalVisibleStorage,
/// hasLazyLocalLexicalLookups, hasLazyExternalLexicalLookups
friend class ASTWriter;

// We use uint64_t in the bit-fields below since some bit-fields
// cross the unsigned boundary and this breaks the packing.

/// Stores the bits used by DeclContext.
/// If modified NumDeclContextBit, the ctor of DeclContext and the accessor
/// methods in DeclContext should be updated appropriately.
class DeclContextBitfields {
  friend class DeclContext;
  /// DeclKind - This indicates which class this is.
  uint64_t DeclKind : 7;

  /// Whether this declaration context also has some external
  /// storage that contains additional declarations that are lexically
  /// part of this context.
  mutable uint64_t ExternalLexicalStorage : 1;

  /// Whether this declaration context also has some external
  /// storage that contains additional declarations that are visible
  /// in this context.
  mutable uint64_t ExternalVisibleStorage : 1;

  /// Whether this declaration context has had externally visible
  /// storage added since the last lookup. In this case, \c LookupPtr's
  /// invariant may not hold and needs to be fixed before we perform
  /// another lookup.
  mutable uint64_t NeedToReconcileExternalVisibleStorage : 1;

  /// If \c true, this context may have local lexical declarations
  /// that are missing from the lookup table.
  mutable uint64_t HasLazyLocalLexicalLookups : 1;

  /// If \c true, the external source may have lexical declarations
  /// that are missing from the lookup table.
  mutable uint64_t HasLazyExternalLexicalLookups : 1;

  /// If \c true, lookups should only return identifier from
  /// DeclContext scope (for example TranslationUnit). Used in
  /// LookupQualifiedName()
  mutable uint64_t UseQualifiedLookup : 1;
};

/// Number of bits in DeclContextBitfields.
enum { NumDeclContextBits = 13 };

/// Stores the bits used by TagDecl.
/// If modified NumTagDeclBits and the accessor
/// methods in TagDecl should be updated appropriately.
class TagDeclBitfields {
  friend class TagDecl;
  /// For the bits in DeclContextBitfields
  uint64_t : NumDeclContextBits;

  /// The TagKind enum.
  uint64_t TagDeclKind : 3;

  /// True if this is a definition ("struct foo {};"), false if it is a
  /// declaration ("struct foo;").  It is not considered a definition
  /// until the definition has been fully processed.
  uint64_t IsCompleteDefinition : 1;

  /// True if this is currently being defined.
  uint64_t IsBeingDefined : 1;

  /// True if this tag declaration is "embedded" (i.e., defined or declared
  /// for the very first time) in the syntax of a declarator.
  uint64_t IsEmbeddedInDeclarator : 1;

  /// True if this tag is free standing, e.g. "struct foo;".
  uint64_t IsFreeStanding : 1;

  /// Indicates whether it is possible for declarations of this kind
  /// to have an out-of-date definition.
  ///
  /// This option is only enabled when modules are enabled.
  uint64_t MayHaveOutOfDateDef : 1;

  /// Has the full definition of this type been required by a use somewhere in
  /// the TU.
  uint64_t IsCompleteDefinitionRequired : 1;
};

/// Number of non-inherited bits in TagDeclBitfields.
enum { NumTagDeclBits = 9 };

/// Stores the bits used by EnumDecl.
/// If modified NumEnumDeclBit and the accessor
/// methods in EnumDecl should be updated appropriately.
class EnumDeclBitfields {
  friend class EnumDecl;
  /// For the bits in DeclContextBitfields.
  uint64_t : NumDeclContextBits;
  /// For the bits in TagDeclBitfields.
  uint64_t : NumTagDeclBits;

  /// Width in bits required to store all the non-negative
  /// enumerators of this enum.
  uint64_t NumPositiveBits : 8;

  /// Width in bits required to store all the negative
  /// enumerators of this enum.
  uint64_t NumNegativeBits : 8;

  /// True if this tag declaration is a scoped enumeration. Only
  /// possible in C++11 mode.
  uint64_t IsScoped : 1;

  /// If this tag declaration is a scoped enum,
  /// then this is true if the scoped enum was declared using the class
  /// tag, false if it was declared with the struct tag. No meaning is
  /// associated if this tag declaration is not a scoped enum.
  uint64_t IsScopedUsingClassTag : 1;

  /// True if this is an enumeration with fixed underlying type. Only
  /// possible in C++11, Microsoft extensions, or Objective C mode.
  uint64_t IsFixed : 1;

  /// True if a valid hash is stored in ODRHash.
  uint64_t HasODRHash : 1;
};

/// Number of non-inherited bits in EnumDeclBitfields.
enum { NumEnumDeclBits = 20 };

/// Stores the bits used by RecordDecl.
/// If modified NumRecordDeclBits and the accessor
/// methods in RecordDecl should be updated appropriately.
class RecordDeclBitfields {
  friend class RecordDecl;
  /// For the bits in DeclContextBitfields.
  uint64_t : NumDeclContextBits;
  /// For the bits in TagDeclBitfields.
  uint64_t : NumTagDeclBits;

  /// This is true if this struct ends with a flexible
  /// array member (e.g. int X[]) or if this union contains a struct that does.
  /// If so, this cannot be contained in arrays or other structs as a member.
  uint64_t HasFlexibleArrayMember : 1;

  /// Whether this is the type of an anonymous struct or union.
  uint64_t AnonymousStructOrUnion : 1;

  /// This is true if this struct has at least one member
  /// containing an Objective-C object pointer type.
  uint64_t HasObjectMember : 1;

  /// This is true if struct has at least one member of
  /// 'volatile' type.
  uint64_t HasVolatileMember : 1;

  /// Whether the field declarations of this record have been loaded
  /// from external storage. To avoid unnecessary deserialization of
  /// methods/nested types we allow deserialization of just the fields
  /// when needed.
  mutable uint64_t LoadedFieldsFromExternalStorage : 1;

  /// Basic properties of non-trivial C structs.
  uint64_t NonTrivialToPrimitiveDefaultInitialize : 1;
  uint64_t NonTrivialToPrimitiveCopy : 1;
  uint64_t NonTrivialToPrimitiveDestroy : 1;

  /// The following bits indicate whether this is or contains a C union that
  /// is non-trivial to default-initialize, destruct, or copy. These bits
  /// imply the associated basic non-triviality predicates declared above.
  uint64_t HasNonTrivialToPrimitiveDefaultInitializeCUnion : 1;
  uint64_t HasNonTrivialToPrimitiveDestructCUnion : 1;
  uint64_t HasNonTrivialToPrimitiveCopyCUnion : 1;

  /// Indicates whether this struct is destroyed in the callee.
  uint64_t ParamDestroyedInCallee : 1;

  /// Represents the way this type is passed to a function.
  uint64_t ArgPassingRestrictions : 2;
};

/// Number of non-inherited bits in RecordDeclBitfields.
enum { NumRecordDeclBits = 14 };

/// Stores the bits used by OMPDeclareReductionDecl.
/// If modified NumOMPDeclareReductionDeclBits and the accessor
/// methods in OMPDeclareReductionDecl should be updated appropriately.
class OMPDeclareReductionDeclBitfields {
  friend class OMPDeclareReductionDecl;
  /// For the bits in DeclContextBitfields
  uint64_t : NumDeclContextBits;

  /// Kind of initializer,
  /// function call or omp_priv<init_expr> initializtion.
  uint64_t InitializerKind : 2;
};

/// Number of non-inherited bits in OMPDeclareReductionDeclBitfields.
enum { NumOMPDeclareReductionDeclBits = 2 };

/// Stores the bits used by FunctionDecl.
/// If modified NumFunctionDeclBits and the accessor
/// methods in FunctionDecl and CXXDeductionGuideDecl
/// (for IsCopyDeductionCandidate) should be updated appropriately.
class FunctionDeclBitfields {
  friend class FunctionDecl;
  /// For IsCopyDeductionCandidate
  friend class CXXDeductionGuideDecl;
  /// For the bits in DeclContextBitfields.
  uint64_t : NumDeclContextBits;

  uint64_t SClass : 3;
  uint64_t IsInline : 1;
  uint64_t IsInlineSpecified : 1;

  uint64_t IsVirtualAsWritten : 1;
  uint64_t IsPure : 1;
  uint64_t HasInheritedPrototype : 1;
  uint64_t HasWrittenPrototype : 1;
  uint64_t IsDeleted : 1;
  /// Used by CXXMethodDecl
  uint64_t IsTrivial : 1;

  /// This flag indicates whether this function is trivial for the purpose of
  /// calls. This is meaningful only when this function is a copy/move
  /// constructor or a destructor.
  uint64_t IsTrivialForCall : 1;

  uint64_t IsDefaulted : 1;
  uint64_t IsExplicitlyDefaulted : 1;
  uint64_t HasDefaultedFunctionInfo : 1;
  uint64_t HasImplicitReturnZero : 1;
  uint64_t IsLateTemplateParsed : 1;

  /// Kind of contexpr specifier as defined by ConstexprSpecKind.
  uint64_t ConstexprKind : 2;
  uint64_t InstantiationIsPending : 1;

  /// Indicates if the function uses __try.
  uint64_t UsesSEHTry : 1;

  /// Indicates if the function was a definition
  /// but its body was skipped.
  uint64_t HasSkippedBody : 1;

  /// Indicates if the function declaration will
  /// have a body, once we're done parsing it.
  uint64_t WillHaveBody : 1;

  /// Indicates that this function is a multiversioned
  /// function using attribute 'target'.
  uint64_t IsMultiVersion : 1;

  /// [C++17] Only used by CXXDeductionGuideDecl. Indicates that
  /// the Deduction Guide is the implicitly generated 'copy
  /// deduction candidate' (is used during overload resolution).
  uint64_t IsCopyDeductionCandidate : 1;

  /// Store the ODRHash after first calculation.
  uint64_t HasODRHash : 1;

  /// Indicates if the function uses Floating Point Constrained Intrinsics
  uint64_t UsesFPIntrin : 1;
};

/// Number of non-inherited bits in FunctionDeclBitfields.
enum { NumFunctionDeclBits = 27 };

/// Stores the bits used by CXXConstructorDecl. If modified
/// NumCXXConstructorDeclBits and the accessor
/// methods in CXXConstructorDecl should be updated appropriately.
class CXXConstructorDeclBitfields {
  friend class CXXConstructorDecl;
  /// For the bits in DeclContextBitfields.
  uint64_t : NumDeclContextBits;
  /// For the bits in FunctionDeclBitfields.
  uint64_t : NumFunctionDeclBits;

  /// 24 bits to fit in the remaining available space.
  /// Note that this makes CXXConstructorDeclBitfields take
  /// exactly 64 bits and thus the width of NumCtorInitializers
  /// will need to be shrunk if some bit is added to NumDeclContextBitfields,
  /// NumFunctionDeclBitfields or CXXConstructorDeclBitfields.
  uint64_t NumCtorInitializers : 21;
  uint64_t IsInheritingConstructor : 1;

  /// Whether this constructor has a trail-allocated explicit specifier.
  uint64_t HasTrailingExplicitSpecifier : 1;
  /// If this constructor does't have a trail-allocated explicit specifier.
  /// Whether this constructor is explicit specified.
  uint64_t IsSimpleExplicit : 1;
};

/// Number of non-inherited bits in CXXConstructorDeclBitfields.
enum {
  NumCXXConstructorDeclBits = 64 - NumDeclContextBits - NumFunctionDeclBits
};

/// Stores the bits used by ObjCMethodDecl.
/// If modified NumObjCMethodDeclBits and the accessor
/// methods in ObjCMethodDecl should be updated appropriately.
class ObjCMethodDeclBitfields {
  friend class ObjCMethodDecl;

  /// For the bits in DeclContextBitfields.
  uint64_t : NumDeclContextBits;

  /// The conventional meaning of this method; an ObjCMethodFamily.
  /// This is not serialized; instead, it is computed on demand and
  /// cached.
  mutable uint64_t Family : ObjCMethodFamilyBitWidth;

  /// instance (true) or class (false) method.
  uint64_t IsInstance : 1;
  uint64_t IsVariadic : 1;

  /// True if this method is the getter or setter for an explicit property.
  uint64_t IsPropertyAccessor : 1;

  /// True if this method is a synthesized property accessor stub.
  uint64_t IsSynthesizedAccessorStub : 1;

  /// Method has a definition.
  uint64_t IsDefined : 1;

  /// Method redeclaration in the same interface.
  uint64_t IsRedeclaration : 1;

  /// Is redeclared in the same interface.
  mutable uint64_t HasRedeclaration : 1;

  /// \@required/\@optional
  uint64_t DeclImplementation : 2;

  /// in, inout, etc.
  uint64_t objcDeclQualifier : 7;

  /// Indicates whether this method has a related result type.
  uint64_t RelatedResultType : 1;

  /// Whether the locations of the selector identifiers are in a
  /// "standard" position, a enum SelectorLocationsKind.
  uint64_t SelLocsKind : 2;

  /// Whether this method overrides any other in the class hierarchy.
  ///
  /// A method is said to override any method in the class's
  /// base classes, its protocols, or its categories' protocols, that has
  /// the same selector and is of the same kind (class or instance).
  /// A method in an implementation is not considered as overriding the same
  /// method in the interface or its categories.
  uint64_t IsOverriding : 1;

  /// Indicates if the method was a definition but its body was skipped.
  uint64_t HasSkippedBody : 1;
};

/// Number of non-inherited bits in ObjCMethodDeclBitfields.
enum { NumObjCMethodDeclBits = 24 };

/// Stores the bits used by ObjCContainerDecl.
/// If modified NumObjCContainerDeclBits and the accessor
/// methods in ObjCContainerDecl should be updated appropriately.
class ObjCContainerDeclBitfields {
  friend class ObjCContainerDecl;
  /// For the bits in DeclContextBitfields
  uint32_t : NumDeclContextBits;

  // Not a bitfield but this saves space.
  // Note that ObjCContainerDeclBitfields is full.
  SourceLocation AtStart;
};

/// Number of non-inherited bits in ObjCContainerDeclBitfields.
/// Note that here we rely on the fact that SourceLocation is 32 bits
/// wide. We check this with the static_assert in the ctor of DeclContext.
enum { NumObjCContainerDeclBits = 64 - NumDeclContextBits };

/// Stores the bits used by LinkageSpecDecl.
/// If modified NumLinkageSpecDeclBits and the accessor
/// methods in LinkageSpecDecl should be updated appropriately.
class LinkageSpecDeclBitfields {
  friend class LinkageSpecDecl;
  /// For the bits in DeclContextBitfields.
  uint64_t : NumDeclContextBits;

  /// The language for this linkage specification with values
  /// in the enum LinkageSpecDecl::LanguageIDs.
  uint64_t Language : 3;

  /// True if this linkage spec has braces.
  /// This is needed so that hasBraces() returns the correct result while the
  /// linkage spec body is being parsed.  Once RBraceLoc has been set this is
  /// not used, so it doesn't need to be serialized.
  uint64_t HasBraces : 1;
};

/// Number of non-inherited bits in LinkageSpecDeclBitfields.
enum { NumLinkageSpecDeclBits = 4 };

/// Stores the bits used by BlockDecl.
/// If modified NumBlockDeclBits and the accessor
/// methods in BlockDecl should be updated appropriately.
class BlockDeclBitfields {
  friend class BlockDecl;
  /// For the bits in DeclContextBitfields.
  uint64_t : NumDeclContextBits;

  uint64_t IsVariadic : 1;
  uint64_t CapturesCXXThis : 1;
  uint64_t BlockMissingReturnType : 1;
  uint64_t IsConversionFromLambda : 1;

  /// A bit that indicates this block is passed directly to a function as a
  /// non-escaping parameter.
  uint64_t DoesNotEscape : 1;

  /// A bit that indicates whether it's possible to avoid coying this block to
  /// the heap when it initializes or is assigned to a local variable with
  /// automatic storage.
  uint64_t CanAvoidCopyToHeap : 1;
};

/// Number of non-inherited bits in BlockDeclBitfields.
enum { NumBlockDeclBits = 5 };

/// Pointer to the data structure used to lookup declarations
/// within this context (or a DependentStoredDeclsMap if this is a
/// dependent context). We maintain the invariant that, if the map
/// contains an entry for a DeclarationName (and we haven't lazily
/// omitted anything), then it contains all relevant entries for that
/// name (modulo the hasExternalDecls() flag).
mutable StoredDeclsMap *LookupPtr = nullptr;

1786protected:
/// This anonymous union stores the bits belonging to DeclContext and classes
/// deriving from it. The goal is to use otherwise wasted
/// space in DeclContext to store data belonging to derived classes.
/// The space saved is especially significient when pointers are aligned
/// to 8 bytes. In this case due to alignment requirements we have a
/// little less than 8 bytes free in DeclContext which we can use.
/// We check that none of the classes in this union is larger than
/// 8 bytes with static_asserts in the ctor of DeclContext.
union {
  DeclContextBitfields DeclContextBits;
  TagDeclBitfields TagDeclBits;
  EnumDeclBitfields EnumDeclBits;
  RecordDeclBitfields RecordDeclBits;
  OMPDeclareReductionDeclBitfields OMPDeclareReductionDeclBits;
  FunctionDeclBitfields FunctionDeclBits;
  CXXConstructorDeclBitfields CXXConstructorDeclBits;
  ObjCMethodDeclBitfields ObjCMethodDeclBits;
  ObjCContainerDeclBitfields ObjCContainerDeclBits;
  LinkageSpecDeclBitfields LinkageSpecDeclBits;
  BlockDeclBitfields BlockDeclBits;

  static_assert(sizeof(DeclContextBitfields) <= 8,
                "DeclContextBitfields is larger than 8 bytes!");
  static_assert(sizeof(TagDeclBitfields) <= 8,
                "TagDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(EnumDeclBitfields) <= 8,
                "EnumDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(RecordDeclBitfields) <= 8,
                "RecordDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(OMPDeclareReductionDeclBitfields) <= 8,
                "OMPDeclareReductionDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(FunctionDeclBitfields) <= 8,
                "FunctionDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(CXXConstructorDeclBitfields) <= 8,
                "CXXConstructorDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(ObjCMethodDeclBitfields) <= 8,
                "ObjCMethodDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(ObjCContainerDeclBitfields) <= 8,
                "ObjCContainerDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(LinkageSpecDeclBitfields) <= 8,
                "LinkageSpecDeclBitfields is larger than 8 bytes!");
  static_assert(sizeof(BlockDeclBitfields) <= 8,
                "BlockDeclBitfields is larger than 8 bytes!");
};

/// FirstDecl - The first declaration stored within this declaration
/// context.
mutable Decl *FirstDecl = nullptr;

/// LastDecl - The last declaration stored within this declaration
/// context. FIXME: We could probably cache this value somewhere
/// outside of the DeclContext, to reduce the size of DeclContext by
/// another pointer.
mutable Decl *LastDecl = nullptr;

/// Build up a chain of declarations.
///
/// \returns the first/last pair of declarations.
static std::pair<Decl *, Decl *>
BuildDeclChain(ArrayRef<Decl*> Decls, bool FieldsAlreadyLoaded);

DeclContext(Decl::Kind K);

1850public:
~DeclContext();

Decl::Kind getDeclKind() const {
  return static_cast<Decl::Kind>(DeclContextBits.DeclKind);
}

const char *getDeclKindName() const;

/// getParent - Returns the containing DeclContext.
DeclContext *getParent() {
  return cast<Decl>(this)->getDeclContext();
}
const DeclContext *getParent() const {
  return const_cast<DeclContext*>(this)->getParent();
}

/// getLexicalParent - Returns the containing lexical DeclContext. May be
/// different from getParent, e.g.:
///
///   namespace A {
///      struct S;
///   }
///   struct A::S {}; // getParent() == namespace 'A'
///                   // getLexicalParent() == translation unit
///
DeclContext *getLexicalParent() {
  return cast<Decl>(this)->getLexicalDeclContext();
}
const DeclContext *getLexicalParent() const {
  return const_cast<DeclContext*>(this)->getLexicalParent();
}

DeclContext *getLookupParent();

const DeclContext *getLookupParent() const {
  return const_cast<DeclContext*>(this)->getLookupParent();
}

ASTContext &getParentASTContext() const {
  return cast<Decl>(this)->getASTContext();
}

bool isClosure() const { return getDeclKind() == Decl::Block; }

/// Return this DeclContext if it is a BlockDecl. Otherwise, return the
/// innermost enclosing BlockDecl or null if there are no enclosing blocks.
const BlockDecl *getInnermostBlockDecl() const;

bool isObjCContainer() const {
  switch (getDeclKind()) {
  case Decl::ObjCCategory:
  case Decl::ObjCCategoryImpl:
  case Decl::ObjCImplementation:
  case Decl::ObjCInterface:
  case Decl::ObjCProtocol:
    return true;
  default:
    return false;
  }
}

bool isFunctionOrMethod() const {
  switch (getDeclKind()) {
  case Decl::Block:
  case Decl::Captured:
  case Decl::ObjCMethod:
    return true;
  default:
    return getDeclKind() >= Decl::firstFunction &&
           getDeclKind() <= Decl::lastFunction;
  }
}

/// Test whether the context supports looking up names.
bool isLookupContext() const {
  return !isFunctionOrMethod() && getDeclKind() != Decl::LinkageSpec &&
         getDeclKind() != Decl::Export;
}

bool isFileContext() const {
  return getDeclKind() == Decl::TranslationUnit ||
         getDeclKind() == Decl::Namespace;
}

bool isTranslationUnit() const {
  return getDeclKind() == Decl::TranslationUnit;
}

bool isRecord() const {
  return getDeclKind() >= Decl::firstRecord &&
         getDeclKind() <= Decl::lastRecord;
}

bool isNamespace() const { return getDeclKind() == Decl::Namespace; }

bool isStdNamespace() const;

bool isInlineNamespace() const;

/// Determines whether this context is dependent on a
/// template parameter.
bool isDependentContext() const;

/// isTransparentContext - Determines whether this context is a
/// "transparent" context, meaning that the members declared in this
/// context are semantically declared in the nearest enclosing
/// non-transparent (opaque) context but are lexically declared in
/// this context. For example, consider the enumerators of an
/// enumeration type:
/// @code
/// enum E {
///   Val1
/// };
/// @endcode
/// Here, E is a transparent context, so its enumerator (Val1) will
/// appear (semantically) that it is in the same context of E.
/// Examples of transparent contexts include: enumerations (except for
/// C++0x scoped enums), and C++ linkage specifications.
bool isTransparentContext() const;

/// Determines whether this context or some of its ancestors is a
/// linkage specification context that specifies C linkage.
bool isExternCContext() const;

/// Retrieve the nearest enclosing C linkage specification context.
const LinkageSpecDecl *getExternCContext() const;

/// Determines whether this context or some of its ancestors is a
/// linkage specification context that specifies C++ linkage.
bool isExternCXXContext() const;

/// Determine whether this declaration context is equivalent
/// to the declaration context DC.
bool Equals(const DeclContext *DC) const {
  return DC && this->getPrimaryContext() == DC->getPrimaryContext();
}

/// Determine whether this declaration context encloses the
/// declaration context DC.
bool Encloses(const DeclContext *DC) const;

/// Find the nearest non-closure ancestor of this context,
/// i.e. the innermost semantic parent of this context which is not
/// a closure.  A context may be its own non-closure ancestor.
Decl *getNonClosureAncestor();
const Decl *getNonClosureAncestor() const {
  return const_cast<DeclContext*>(this)->getNonClosureAncestor();
}

/// getPrimaryContext - There may be many different
/// declarations of the same entity (including forward declarations
/// of classes, multiple definitions of namespaces, etc.), each with
/// a different set of declarations. This routine returns the
/// "primary" DeclContext structure, which will contain the
/// information needed to perform name lookup into this context.
DeclContext *getPrimaryContext();
const DeclContext *getPrimaryContext() const {
  return const_cast<DeclContext*>(this)->getPrimaryContext();
}

/// getRedeclContext - Retrieve the context in which an entity conflicts with
/// other entities of the same name, or where it is a redeclaration if the
/// two entities are compatible. This skips through transparent contexts.
DeclContext *getRedeclContext();
const DeclContext *getRedeclContext() const {
  return const_cast<DeclContext *>(this)->getRedeclContext();
}

/// Retrieve the nearest enclosing namespace context.
DeclContext *getEnclosingNamespaceContext();
const DeclContext *getEnclosingNamespaceContext() const {
  return const_cast<DeclContext *>(this)->getEnclosingNamespaceContext();
}

/// Retrieve the outermost lexically enclosing record context.
RecordDecl *getOuterLexicalRecordContext();
const RecordDecl *getOuterLexicalRecordContext() const {
  return const_cast<DeclContext *>(this)->getOuterLexicalRecordContext();
}

/// Test if this context is part of the enclosing namespace set of
/// the context NS, as defined in C++0x [namespace.def]p9. If either context
/// isn't a namespace, this is equivalent to Equals().
///
/// The enclosing namespace set of a namespace is the namespace and, if it is
/// inline, its enclosing namespace, recursively.
bool InEnclosingNamespaceSetOf(const DeclContext *NS) const;

/// Collects all of the declaration contexts that are semantically
/// connected to this declaration context.
///
/// For declaration contexts that have multiple semantically connected but
/// syntactically distinct contexts, such as C++ namespaces, this routine
/// retrieves the complete set of such declaration contexts in source order.
/// For example, given:
///
/// \code
/// namespace N {
///   int x;
/// }
/// namespace N {
///   int y;
/// }
/// \endcode
///
/// The \c Contexts parameter will contain both definitions of N.
///
/// \param Contexts Will be cleared and set to the set of declaration
/// contexts that are semanticaly connected to this declaration context,
/// in source order, including this context (which may be the only result,
/// for non-namespace contexts).
void collectAllContexts(SmallVectorImpl<DeclContext *> &Contexts);

/// decl_iterator - Iterates through the declarations stored
/// within this context.
class decl_iterator {
  /// Current - The current declaration.
  Decl *Current = nullptr;

public:
  using value_type = Decl *;
  using reference = const value_type &;
  using pointer = const value_type *;
  using iterator_category = std::forward_iterator_tag;
  using difference_type = std::ptrdiff_t;

  decl_iterator() = default;
  explicit decl_iterator(Decl *C) : Current(C) {}

  reference operator*() const { return Current; }

  // This doesn't meet the iterator requirements, but it's convenient
  value_type operator->() const { return Current; }

  decl_iterator& operator++() {
    Current = Current->getNextDeclInContext();
    return *this;
  }

  decl_iterator operator++(int) {
    decl_iterator tmp(*this);
    ++(*this);
    return tmp;
  }

  friend bool operator==(decl_iterator x, decl_iterator y) {
    return x.Current == y.Current;
46
←
Assuming 'x.Current' is not equal to 'y.Current'→
47
←
Returning zero, which participates in a condition later→
  }

  friend bool operator!=(decl_iterator x, decl_iterator y) {
    return x.Current != y.Current;
  }
};

using decl_range = llvm::iterator_range<decl_iterator>;

/// decls_begin/decls_end - Iterate over the declarations stored in
/// this context.
decl_range decls() const { return decl_range(decls_begin(), decls_end()); }
decl_iterator decls_begin() const;
decl_iterator decls_end() const { return decl_iterator(); }
bool decls_empty() const;

/// noload_decls_begin/end - Iterate over the declarations stored in this
/// context that are currently loaded; don't attempt to retrieve anything
/// from an external source.
decl_range noload_decls() const {
  return decl_range(noload_decls_begin(), noload_decls_end());
}
decl_iterator noload_decls_begin() const { return decl_iterator(FirstDecl); }
decl_iterator noload_decls_end() const { return decl_iterator(); }

/// specific_decl_iterator - Iterates over a subrange of
/// declarations stored in a DeclContext, providing only those that
/// are of type SpecificDecl (or a class derived from it). This
/// iterator is used, for example, to provide iteration over just
/// the fields within a RecordDecl (with SpecificDecl = FieldDecl).
template<typename SpecificDecl>
class specific_decl_iterator {
  /// Current - The current, underlying declaration iterator, which
  /// will either be NULL or will point to a declaration of
  /// type SpecificDecl.
  DeclContext::decl_iterator Current;

  /// SkipToNextDecl - Advances the current position up to the next
  /// declaration of type SpecificDecl that also meets the criteria
  /// required by Acceptable.
  void SkipToNextDecl() {
    while (*Current && !isa<SpecificDecl>(*Current))
      ++Current;
  }

public:
  using value_type = SpecificDecl *;
  // TODO: Add reference and pointer types (with some appropriate proxy type)
  // if we ever have a need for them.
  using reference = void;
  using pointer = void;
  using difference_type =
      std::iterator_traits<DeclContext::decl_iterator>::difference_type;
  using iterator_category = std::forward_iterator_tag;

  specific_decl_iterator() = default;

  /// specific_decl_iterator - Construct a new iterator over a
  /// subset of the declarations the range [C,
  /// end-of-declarations). If A is non-NULL, it is a pointer to a
  /// member function of SpecificDecl that should return true for
  /// all of the SpecificDecl instances that will be in the subset
  /// of iterators. For example, if you want Objective-C instance
  /// methods, SpecificDecl will be ObjCMethodDecl and A will be
  /// &ObjCMethodDecl::isInstanceMethod.
  explicit specific_decl_iterator(DeclContext::decl_iterator C) : Current(C) {
    SkipToNextDecl();
  }

  value_type operator*() const { return cast<SpecificDecl>(*Current); }

  // This doesn't meet the iterator requirements, but it's convenient
  value_type operator->() const { return **this; }

  specific_decl_iterator& operator++() {
    ++Current;
    SkipToNextDecl();
    return *this;
  }

  specific_decl_iterator operator++(int) {
    specific_decl_iterator tmp(*this);
    ++(*this);
    return tmp;
  }

  friend bool operator==(const specific_decl_iterator& x,
                         const specific_decl_iterator& y) {
    return x.Current == y.Current;
45
←
Calling 'operator=='→
48
←
Returning from 'operator=='→
49
←
Returning zero, which participates in a condition later→
  }

  friend bool operator!=(const specific_decl_iterator& x,
                         const specific_decl_iterator& y) {
    return x.Current != y.Current;
  }
};

/// Iterates over a filtered subrange of declarations stored
/// in a DeclContext.
///
/// This iterator visits only those declarations that are of type
/// SpecificDecl (or a class derived from it) and that meet some
/// additional run-time criteria. This iterator is used, for
/// example, to provide access to the instance methods within an
/// Objective-C interface (with SpecificDecl = ObjCMethodDecl and
/// Acceptable = ObjCMethodDecl::isInstanceMethod).
template<typename SpecificDecl, bool (SpecificDecl::*Acceptable)() const>
class filtered_decl_iterator {
  /// Current - The current, underlying declaration iterator, which
  /// will either be NULL or will point to a declaration of
  /// type SpecificDecl.
  DeclContext::decl_iterator Current;

  /// SkipToNextDecl - Advances the current position up to the next
  /// declaration of type SpecificDecl that also meets the criteria
  /// required by Acceptable.
  void SkipToNextDecl() {
    while (*Current &&
           (!isa<SpecificDecl>(*Current) ||
            (Acceptable && !(cast<SpecificDecl>(*Current)->*Acceptable)())))
      ++Current;
  }

public:
  using value_type = SpecificDecl *;
  // TODO: Add reference and pointer types (with some appropriate proxy type)
  // if we ever have a need for them.
  using reference = void;
  using pointer = void;
  using difference_type =
      std::iterator_traits<DeclContext::decl_iterator>::difference_type;
  using iterator_category = std::forward_iterator_tag;

  filtered_decl_iterator() = default;

  /// filtered_decl_iterator - Construct a new iterator over a
  /// subset of the declarations the range [C,
  /// end-of-declarations). If A is non-NULL, it is a pointer to a
  /// member function of SpecificDecl that should return true for
  /// all of the SpecificDecl instances that will be in the subset
  /// of iterators. For example, if you want Objective-C instance
  /// methods, SpecificDecl will be ObjCMethodDecl and A will be
  /// &ObjCMethodDecl::isInstanceMethod.
  explicit filtered_decl_iterator(DeclContext::decl_iterator C) : Current(C) {
    SkipToNextDecl();
  }

  value_type operator*() const { return cast<SpecificDecl>(*Current); }
  value_type operator->() const { return cast<SpecificDecl>(*Current); }

  filtered_decl_iterator& operator++() {
    ++Current;
    SkipToNextDecl();
    return *this;
  }

  filtered_decl_iterator operator++(int) {
    filtered_decl_iterator tmp(*this);
    ++(*this);
    return tmp;
  }

  friend bool operator==(const filtered_decl_iterator& x,
                         const filtered_decl_iterator& y) {
    return x.Current == y.Current;
  }

  friend bool operator!=(const filtered_decl_iterator& x,
                         const filtered_decl_iterator& y) {
    return x.Current != y.Current;
  }
};

/// Add the declaration D into this context.
///
/// This routine should be invoked when the declaration D has first
/// been declared, to place D into the context where it was
/// (lexically) defined. Every declaration must be added to one
/// (and only one!) context, where it can be visited via
/// [decls_begin(), decls_end()). Once a declaration has been added
/// to its lexical context, the corresponding DeclContext owns the
/// declaration.
///
/// If D is also a NamedDecl, it will be made visible within its
/// semantic context via makeDeclVisibleInContext.
void addDecl(Decl *D);

/// Add the declaration D into this context, but suppress
/// searches for external declarations with the same name.
///
/// Although analogous in function to addDecl, this removes an
/// important check.  This is only useful if the Decl is being
/// added in response to an external search; in all other cases,
/// addDecl() is the right function to use.
/// See the ASTImporter for use cases.
void addDeclInternal(Decl *D);

/// Add the declaration D to this context without modifying
/// any lookup tables.
///
/// This is useful for some operations in dependent contexts where
/// the semantic context might not be dependent;  this basically
/// only happens with friends.
void addHiddenDecl(Decl *D);

/// Removes a declaration from this context.
void removeDecl(Decl *D);

/// Checks whether a declaration is in this context.
bool containsDecl(Decl *D) const;

/// Checks whether a declaration is in this context.
/// This also loads the Decls from the external source before the check.
bool containsDeclAndLoad(Decl *D) const;

using lookup_result = DeclContextLookupResult;
using lookup_iterator = lookup_result::iterator;

/// lookup - Find the declarations (if any) with the given Name in
/// this context. Returns a range of iterators that contains all of
/// the declarations with this name, with object, function, member,
/// and enumerator names preceding any tag name. Note that this
/// routine will not look into parent contexts.
lookup_result lookup(DeclarationName Name) const;

/// Find the declarations with the given name that are visible
/// within this context; don't attempt to retrieve anything from an
/// external source.
lookup_result noload_lookup(DeclarationName Name);

/// A simplistic name lookup mechanism that performs name lookup
/// into this declaration context without consulting the external source.
///
/// This function should almost never be used, because it subverts the
/// usual relationship between a DeclContext and the external source.
/// See the ASTImporter for the (few, but important) use cases.
///
/// FIXME: This is very inefficient; replace uses of it with uses of
/// noload_lookup.
void localUncachedLookup(DeclarationName Name,
                         SmallVectorImpl<NamedDecl *> &Results);

/// Makes a declaration visible within this context.
///
/// This routine makes the declaration D visible to name lookup
/// within this context and, if this is a transparent context,
/// within its parent contexts up to the first enclosing
/// non-transparent context. Making a declaration visible within a
/// context does not transfer ownership of a declaration, and a
/// declaration can be visible in many contexts that aren't its
/// lexical context.
///
/// If D is a redeclaration of an existing declaration that is
/// visible from this context, as determined by
/// NamedDecl::declarationReplaces, the previous declaration will be
/// replaced with D.
void makeDeclVisibleInContext(NamedDecl *D);

/// all_lookups_iterator - An iterator that provides a view over the results
/// of looking up every possible name.
class all_lookups_iterator;

using lookups_range = llvm::iterator_range<all_lookups_iterator>;

lookups_range lookups() const;
// Like lookups(), but avoids loading external declarations.
// If PreserveInternalState, avoids building lookup data structures too.
lookups_range noload_lookups(bool PreserveInternalState) const;

/// Iterators over all possible lookups within this context.
all_lookups_iterator lookups_begin() const;
all_lookups_iterator lookups_end() const;

/// Iterators over all possible lookups within this context that are
/// currently loaded; don't attempt to retrieve anything from an external
/// source.
all_lookups_iterator noload_lookups_begin() const;
all_lookups_iterator noload_lookups_end() const;

struct udir_iterator;

using udir_iterator_base =
    llvm::iterator_adaptor_base<udir_iterator, lookup_iterator,
                                typename lookup_iterator::iterator_category,
                                UsingDirectiveDecl *>;

struct udir_iterator : udir_iterator_base {
  udir_iterator(lookup_iterator I) : udir_iterator_base(I) {}

  UsingDirectiveDecl *operator*() const;
};

using udir_range = llvm::iterator_range<udir_iterator>;

udir_range using_directives() const;

// These are all defined in DependentDiagnostic.h.
class ddiag_iterator;

using ddiag_range = llvm::iterator_range<DeclContext::ddiag_iterator>;

inline ddiag_range ddiags() const;

// Low-level accessors

/// Mark that there are external lexical declarations that we need
/// to include in our lookup table (and that are not available as external
/// visible lookups). These extra lookup results will be found by walking
/// the lexical declarations of this context. This should be used only if
/// setHasExternalLexicalStorage() has been called on any decl context for
/// which this is the primary context.
void setMustBuildLookupTable() {
  assert(this == getPrimaryContext() &&((void)0)
         "should only be called on primary context")((void)0);
  DeclContextBits.HasLazyExternalLexicalLookups = true;
}

/// Retrieve the internal representation of the lookup structure.
/// This may omit some names if we are lazily building the structure.
StoredDeclsMap *getLookupPtr() const { return LookupPtr; }

/// Ensure the lookup structure is fully-built and return it.
StoredDeclsMap *buildLookup();

/// Whether this DeclContext has external storage containing
/// additional declarations that are lexically in this context.
bool hasExternalLexicalStorage() const {
  return DeclContextBits.ExternalLexicalStorage;
}

/// State whether this DeclContext has external storage for
/// declarations lexically in this context.
void setHasExternalLexicalStorage(bool ES = true) const {
  DeclContextBits.ExternalLexicalStorage = ES;
}

/// Whether this DeclContext has external storage containing
/// additional declarations that are visible in this context.
bool hasExternalVisibleStorage() const {
  return DeclContextBits.ExternalVisibleStorage;
}

/// State whether this DeclContext has external storage for
/// declarations visible in this context.
void setHasExternalVisibleStorage(bool ES = true) const {
  DeclContextBits.ExternalVisibleStorage = ES;
  if (ES && LookupPtr)
    DeclContextBits.NeedToReconcileExternalVisibleStorage = true;
}

/// Determine whether the given declaration is stored in the list of
/// declarations lexically within this context.
bool isDeclInLexicalTraversal(const Decl *D) const {
  return D && (D->NextInContextAndBits.getPointer() || D == FirstDecl ||
               D == LastDecl);
}

bool setUseQualifiedLookup(bool use = true) const {
  bool old_value = DeclContextBits.UseQualifiedLookup;
  DeclContextBits.UseQualifiedLookup = use;
  return old_value;
}

bool shouldUseQualifiedLookup() const {
  return DeclContextBits.UseQualifiedLookup;
}

static bool classof(const Decl *D);
static bool classof(const DeclContext *D) { return true; }

void dumpDeclContext() const;
void dumpLookups() const;
void dumpLookups(llvm::raw_ostream &OS, bool DumpDecls = false,
                 bool Deserialize = false) const;

2473private:
/// Whether this declaration context has had externally visible
/// storage added since the last lookup. In this case, \c LookupPtr's
/// invariant may not hold and needs to be fixed before we perform
/// another lookup.
bool hasNeedToReconcileExternalVisibleStorage() const {
  return DeclContextBits.NeedToReconcileExternalVisibleStorage;
}

/// State that this declaration context has had externally visible
/// storage added since the last lookup. In this case, \c LookupPtr's
/// invariant may not hold and needs to be fixed before we perform
/// another lookup.
void setNeedToReconcileExternalVisibleStorage(bool Need = true) const {
  DeclContextBits.NeedToReconcileExternalVisibleStorage = Need;
}

/// If \c true, this context may have local lexical declarations
/// that are missing from the lookup table.
bool hasLazyLocalLexicalLookups() const {
  return DeclContextBits.HasLazyLocalLexicalLookups;
}

/// If \c true, this context may have local lexical declarations
/// that are missing from the lookup table.
void setHasLazyLocalLexicalLookups(bool HasLLLL = true) const {
  DeclContextBits.HasLazyLocalLexicalLookups = HasLLLL;
}

/// If \c true, the external source may have lexical declarations
/// that are missing from the lookup table.
bool hasLazyExternalLexicalLookups() const {
  return DeclContextBits.HasLazyExternalLexicalLookups;
}

/// If \c true, the external source may have lexical declarations
/// that are missing from the lookup table.
void setHasLazyExternalLexicalLookups(bool HasLELL = true) const {
  DeclContextBits.HasLazyExternalLexicalLookups = HasLELL;
}

void reconcileExternalVisibleStorage() const;
bool LoadLexicalDeclsFromExternalStorage() const;

/// Makes a declaration visible within this context, but
/// suppresses searches for external declarations with the same
/// name.
///
/// Analogous to makeDeclVisibleInContext, but for the exclusive
/// use of addDeclInternal().
void makeDeclVisibleInContextInternal(NamedDecl *D);

StoredDeclsMap *CreateStoredDeclsMap(ASTContext &C) const;

void loadLazyLocalLexicalLookups();
void buildLookupImpl(DeclContext *DCtx, bool Internal);
void makeDeclVisibleInContextWithFlags(NamedDecl *D, bool Internal,
                                       bool Rediscoverable);
void makeDeclVisibleInContextImpl(NamedDecl *D, bool Internal);
2532};

2534inline bool Decl::isTemplateParameter() const {
return getKind() == TemplateTypeParm || getKind() == NonTypeTemplateParm ||
       getKind() == TemplateTemplateParm;
2537}

2539// Specialization selected when ToTy is not a known subclass of DeclContext.
2540template <class ToTy,
        bool IsKnownSubtype = ::std::is_base_of<DeclContext, ToTy>::value>
2542struct cast_convert_decl_context {
static const ToTy *doit(const DeclContext *Val) {
  return static_cast<const ToTy*>(Decl::castFromDeclContext(Val));
}

static ToTy *doit(DeclContext *Val) {
  return static_cast<ToTy*>(Decl::castFromDeclContext(Val));
}
2550};

2552// Specialization selected when ToTy is a known subclass of DeclContext.
2553template <class ToTy>
2554struct cast_convert_decl_context<ToTy, true> {
static const ToTy *doit(const DeclContext *Val) {
  return static_cast<const ToTy*>(Val);
}

static ToTy *doit(DeclContext *Val) {
  return static_cast<ToTy*>(Val);
}
2562};

2564} // namespace clang

2566namespace llvm {

2568/// isa<T>(DeclContext*)
2569template <typename To>
2570struct isa_impl<To, ::clang::DeclContext> {
static bool doit(const ::clang::DeclContext &Val) {
  return To::classofKind(Val.getDeclKind());
}
2574};

2576/// cast<T>(DeclContext*)
2577template<class ToTy>
2578struct cast_convert_val<ToTy,
                      const ::clang::DeclContext,const ::clang::DeclContext> {
static const ToTy &doit(const ::clang::DeclContext &Val) {
  return *::clang::cast_convert_decl_context<ToTy>::doit(&Val);
}
2583};

2585template<class ToTy>
2586struct cast_convert_val<ToTy, ::clang::DeclContext, ::clang::DeclContext> {
static ToTy &doit(::clang::DeclContext &Val) {
  return *::clang::cast_convert_decl_context<ToTy>::doit(&Val);
}
2590};

2592template<class ToTy>
2593struct cast_convert_val<ToTy,
                   const ::clang::DeclContext*, const ::clang::DeclContext*> {
static const ToTy *doit(const ::clang::DeclContext *Val) {
  return ::clang::cast_convert_decl_context<ToTy>::doit(Val);
}
2598};

2600template<class ToTy>
2601struct cast_convert_val<ToTy, ::clang::DeclContext*, ::clang::DeclContext*> {
static ToTy *doit(::clang::DeclContext *Val) {
  return ::clang::cast_convert_decl_context<ToTy>::doit(Val);
}
2605};

2607/// Implement cast_convert_val for Decl -> DeclContext conversions.
2608template<class FromTy>
2609struct cast_convert_val< ::clang::DeclContext, FromTy, FromTy> {
static ::clang::DeclContext &doit(const FromTy &Val) {
  return *FromTy::castToDeclContext(&Val);
}
2613};

2615template<class FromTy>
2616struct cast_convert_val< ::clang::DeclContext, FromTy*, FromTy*> {
static ::clang::DeclContext *doit(const FromTy *Val) {
  return FromTy::castToDeclContext(Val);
}
2620};

2622template<class FromTy>
2623struct cast_convert_val< const ::clang::DeclContext, FromTy, FromTy> {
static const ::clang::DeclContext &doit(const FromTy &Val) {
  return *FromTy::castToDeclContext(&Val);
}
2627};

2629template<class FromTy>
2630struct cast_convert_val< const ::clang::DeclContext, FromTy*, FromTy*> {
static const ::clang::DeclContext *doit(const FromTy *Val) {
  return FromTy::castToDeclContext(Val);
}
2634};

2636} // namespace llvm

2638#endif // LLVM_CLANG_AST_DECLBASE_H

←

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/include/clang/AST/APValue.h

→

1//===--- APValue.h - Union class for APFloat/APSInt/Complex -----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file defines the APValue class.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_CLANG_AST_APVALUE_H
14#define LLVM_CLANG_AST_APVALUE_H

16#include "clang/Basic/LLVM.h"
17#include "llvm/ADT/APFixedPoint.h"
18#include "llvm/ADT/APFloat.h"
19#include "llvm/ADT/APSInt.h"
20#include "llvm/ADT/FoldingSet.h"
21#include "llvm/ADT/PointerIntPair.h"
22#include "llvm/ADT/PointerUnion.h"
23#include "llvm/Support/AlignOf.h"

25namespace clang {
26namespace serialization {
27template <typename T> class BasicReaderBase;
28} // end namespace serialization

class AddrLabelExpr;
class ASTContext;
class CharUnits;
class CXXRecordDecl;
class Decl;
class DiagnosticBuilder;
class Expr;
class FieldDecl;
struct PrintingPolicy;
class Type;
class ValueDecl;
class QualType;

43/// Symbolic representation of typeid(T) for some type T.
44class TypeInfoLValue {
const Type *T;

47public:
TypeInfoLValue() : T() {}
explicit TypeInfoLValue(const Type *T);

const Type *getType() const { return T; }
explicit operator bool() const { return T; }

void *getOpaqueValue() { return const_cast<Type*>(T); }
static TypeInfoLValue getFromOpaqueValue(void *Value) {
  TypeInfoLValue V;
  V.T = reinterpret_cast<const Type*>(Value);
  return V;
}

void print(llvm::raw_ostream &Out, const PrintingPolicy &Policy) const;
62};

64/// Symbolic representation of a dynamic allocation.
65class DynamicAllocLValue {
unsigned Index;

68public:
DynamicAllocLValue() : Index(0) {}
explicit DynamicAllocLValue(unsigned Index) : Index(Index + 1) {}
unsigned getIndex() { return Index - 1; }

explicit operator bool() const { return Index != 0; }

void *getOpaqueValue() {
  return reinterpret_cast<void *>(static_cast<uintptr_t>(Index)
                                  << NumLowBitsAvailable);
}
static DynamicAllocLValue getFromOpaqueValue(void *Value) {
  DynamicAllocLValue V;
  V.Index = reinterpret_cast<uintptr_t>(Value) >> NumLowBitsAvailable;
  return V;
}

static unsigned getMaxIndex() {
  return (std::numeric_limits<unsigned>::max() >> NumLowBitsAvailable) - 1;
}

static constexpr int NumLowBitsAvailable = 3;
90};
91}

93namespace llvm {
94template<> struct PointerLikeTypeTraits<clang::TypeInfoLValue> {
static void *getAsVoidPointer(clang::TypeInfoLValue V) {
  return V.getOpaqueValue();
}
static clang::TypeInfoLValue getFromVoidPointer(void *P) {
  return clang::TypeInfoLValue::getFromOpaqueValue(P);
}
// Validated by static_assert in APValue.cpp; hardcoded to avoid needing
// to include Type.h.
static constexpr int NumLowBitsAvailable = 3;
104};

106template<> struct PointerLikeTypeTraits<clang::DynamicAllocLValue> {
static void *getAsVoidPointer(clang::DynamicAllocLValue V) {
  return V.getOpaqueValue();
}
static clang::DynamicAllocLValue getFromVoidPointer(void *P) {
  return clang::DynamicAllocLValue::getFromOpaqueValue(P);
}
static constexpr int NumLowBitsAvailable =
    clang::DynamicAllocLValue::NumLowBitsAvailable;
115};
116}

118namespace clang {
119/// APValue - This class implements a discriminated union of [uninitialized]
120/// [APSInt] [APFloat], [Complex APSInt] [Complex APFloat], [Expr + Offset],
121/// [Vector: N * APValue], [Array: N * APValue]
122class APValue {
typedef llvm::APFixedPoint APFixedPoint;
typedef llvm::APSInt APSInt;
typedef llvm::APFloat APFloat;
126public:
enum ValueKind {
  /// There is no such object (it's outside its lifetime).
  None,
  /// This object has an indeterminate value (C++ [basic.indet]).
  Indeterminate,
  Int,
  Float,
  FixedPoint,
  ComplexInt,
  ComplexFloat,
  LValue,
  Vector,
  Array,
  Struct,
  Union,
  MemberPointer,
  AddrLabelDiff
};

class LValueBase {
  typedef llvm::PointerUnion<const ValueDecl *, const Expr *, TypeInfoLValue,
                             DynamicAllocLValue>
      PtrTy;

public:
  LValueBase() : Local{} {}
  LValueBase(const ValueDecl *P, unsigned I = 0, unsigned V = 0);
  LValueBase(const Expr *P, unsigned I = 0, unsigned V = 0);
  static LValueBase getDynamicAlloc(DynamicAllocLValue LV, QualType Type);
  static LValueBase getTypeInfo(TypeInfoLValue LV, QualType TypeInfo);

  void Profile(llvm::FoldingSetNodeID &ID) const;

  template <class T>
  bool is() const { return Ptr.is<T>(); }

  template <class T>
  T get() const { return Ptr.get<T>(); }

  template <class T>
  T dyn_cast() const { return Ptr.dyn_cast<T>(); }
72
←
Calling 'PointerUnion::dyn_cast'→
79
←
Returning from 'PointerUnion::dyn_cast'→
80
←
Returning null pointer, which participates in a condition later→

  void *getOpaqueValue() const;

  bool isNull() const;

  explicit operator bool() const;

  unsigned getCallIndex() const;
  unsigned getVersion() const;
  QualType getTypeInfoType() const;
  QualType getDynamicAllocType() const;

  QualType getType() const;

  friend bool operator==(const LValueBase &LHS, const LValueBase &RHS);
  friend bool operator!=(const LValueBase &LHS, const LValueBase &RHS) {
    return !(LHS == RHS);
  }
  friend llvm::hash_code hash_value(const LValueBase &Base);
  friend struct llvm::DenseMapInfo<LValueBase>;

private:
  PtrTy Ptr;
  struct LocalState {
    unsigned CallIndex, Version;
  };
  union {
    LocalState Local;
    /// The type std::type_info, if this is a TypeInfoLValue.
    void *TypeInfoType;
    /// The QualType, if this is a DynamicAllocLValue.
    void *DynamicAllocType;
  };
};

/// A FieldDecl or CXXRecordDecl, along with a flag indicating whether we
/// mean a virtual or non-virtual base class subobject.
typedef llvm::PointerIntPair<const Decl *, 1, bool> BaseOrMemberType;

/// A non-discriminated union of a base, field, or array index.
class LValuePathEntry {
  static_assert(sizeof(uintptr_t) <= sizeof(uint64_t),
                "pointer doesn't fit in 64 bits?");
  uint64_t Value;

public:
  LValuePathEntry() : Value() {}
  LValuePathEntry(BaseOrMemberType BaseOrMember);
  static LValuePathEntry ArrayIndex(uint64_t Index) {
    LValuePathEntry Result;
    Result.Value = Index;
    return Result;
  }

  BaseOrMemberType getAsBaseOrMember() const {
    return BaseOrMemberType::getFromOpaqueValue(
        reinterpret_cast<void *>(Value));
  }
  uint64_t getAsArrayIndex() const { return Value; }

  void Profile(llvm::FoldingSetNodeID &ID) const;

  friend bool operator==(LValuePathEntry A, LValuePathEntry B) {
    return A.Value == B.Value;
  }
  friend bool operator!=(LValuePathEntry A, LValuePathEntry B) {
    return A.Value != B.Value;
  }
  friend llvm::hash_code hash_value(LValuePathEntry A) {
    return llvm::hash_value(A.Value);
  }
};
class LValuePathSerializationHelper {
  const void *ElemTy;

public:
  ArrayRef<LValuePathEntry> Path;

  LValuePathSerializationHelper(ArrayRef<LValuePathEntry>, QualType);
  QualType getType();
};
struct NoLValuePath {};
struct UninitArray {};
struct UninitStruct {};

template <typename Impl> friend class clang::serialization::BasicReaderBase;
friend class ASTImporter;
friend class ASTNodeImporter;

257private:
ValueKind Kind;

struct ComplexAPSInt {
  APSInt Real, Imag;
  ComplexAPSInt() : Real(1), Imag(1) {}
};
struct ComplexAPFloat {
  APFloat Real, Imag;
  ComplexAPFloat() : Real(0.0), Imag(0.0) {}
};
struct LV;
struct Vec {
  APValue *Elts;
  unsigned NumElts;
  Vec() : Elts(nullptr), NumElts(0) {}
  ~Vec() { delete[] Elts; }
};
struct Arr {
  APValue *Elts;
  unsigned NumElts, ArrSize;
  Arr(unsigned NumElts, unsigned ArrSize);
  ~Arr();
};
struct StructData {
  APValue *Elts;
  unsigned NumBases;
  unsigned NumFields;
  StructData(unsigned NumBases, unsigned NumFields);
  ~StructData();
};
struct UnionData {
  const FieldDecl *Field;
  APValue *Value;
  UnionData();
  ~UnionData();
};
struct AddrLabelDiffData {
  const AddrLabelExpr* LHSExpr;
  const AddrLabelExpr* RHSExpr;
};
struct MemberPointerData;

// We ensure elsewhere that Data is big enough for LV and MemberPointerData.
typedef llvm::AlignedCharArrayUnion<void *, APSInt, APFloat, ComplexAPSInt,
                                    ComplexAPFloat, Vec, Arr, StructData,
                                    UnionData, AddrLabelDiffData> DataType;
static const size_t DataSize = sizeof(DataType);

DataType Data;

308public:
APValue() : Kind(None) {}
explicit APValue(APSInt I) : Kind(None) {
  MakeInt(); setInt(std::move(I));
}
explicit APValue(APFloat F) : Kind(None) {
  MakeFloat(); setFloat(std::move(F));
}
explicit APValue(APFixedPoint FX) : Kind(None) {
  MakeFixedPoint(std::move(FX));
}
explicit APValue(const APValue *E, unsigned N) : Kind(None) {
  MakeVector(); setVector(E, N);
}
APValue(APSInt R, APSInt I) : Kind(None) {
  MakeComplexInt(); setComplexInt(std::move(R), std::move(I));
}
APValue(APFloat R, APFloat I) : Kind(None) {
  MakeComplexFloat(); setComplexFloat(std::move(R), std::move(I));
}
APValue(const APValue &RHS);
APValue(APValue &&RHS);
APValue(LValueBase B, const CharUnits &O, NoLValuePath N,
        bool IsNullPtr = false)
    : Kind(None) {
  MakeLValue(); setLValue(B, O, N, IsNullPtr);
}
APValue(LValueBase B, const CharUnits &O, ArrayRef<LValuePathEntry> Path,
        bool OnePastTheEnd, bool IsNullPtr = false)
    : Kind(None) {
  MakeLValue(); setLValue(B, O, Path, OnePastTheEnd, IsNullPtr);
}
APValue(UninitArray, unsigned InitElts, unsigned Size) : Kind(None) {
  MakeArray(InitElts, Size);
}
APValue(UninitStruct, unsigned B, unsigned M) : Kind(None) {
  MakeStruct(B, M);
}
explicit APValue(const FieldDecl *D, const APValue &V = APValue())
    : Kind(None) {
  MakeUnion(); setUnion(D, V);
}
APValue(const ValueDecl *Member, bool IsDerivedMember,
        ArrayRef<const CXXRecordDecl*> Path) : Kind(None) {
  MakeMemberPointer(Member, IsDerivedMember, Path);
}
APValue(const AddrLabelExpr* LHSExpr, const AddrLabelExpr* RHSExpr)
    : Kind(None) {
  MakeAddrLabelDiff(); setAddrLabelDiff(LHSExpr, RHSExpr);
}
static APValue IndeterminateValue() {
  APValue Result;
  Result.Kind = Indeterminate;
  return Result;
}

APValue &operator=(const APValue &RHS);
APValue &operator=(APValue &&RHS);

~APValue() {
  if (Kind != None && Kind != Indeterminate)
    DestroyDataAndMakeUninit();
}

/// Returns whether the object performed allocations.
///
/// If APValues are constructed via placement new, \c needsCleanup()
/// indicates whether the destructor must be called in order to correctly
/// free all allocated memory.
bool needsCleanup() const;

/// Swaps the contents of this and the given APValue.
void swap(APValue &RHS);

/// profile this value. There is no guarantee that values of different
/// types will not produce the same profiled value, so the type should
/// typically also be profiled if it's not implied by the context.
void Profile(llvm::FoldingSetNodeID &ID) const;

ValueKind getKind() const { return Kind; }

bool isAbsent() const { return Kind == None; }
bool isIndeterminate() const { return Kind == Indeterminate; }
bool hasValue() const { return Kind != None && Kind != Indeterminate; }

bool isInt() const { return Kind == Int; }
bool isFloat() const { return Kind == Float; }
bool isFixedPoint() const { return Kind == FixedPoint; }
bool isComplexInt() const { return Kind == ComplexInt; }
bool isComplexFloat() const { return Kind == ComplexFloat; }
bool isLValue() const { return Kind == LValue; }
bool isVector() const { return Kind == Vector; }
bool isArray() const { return Kind == Array; }
bool isStruct() const { return Kind == Struct; }
bool isUnion() const { return Kind == Union; }
bool isMemberPointer() const { return Kind == MemberPointer; }
bool isAddrLabelDiff() const { return Kind == AddrLabelDiff; }

void dump() const;
void dump(raw_ostream &OS, const ASTContext &Context) const;

void printPretty(raw_ostream &OS, const ASTContext &Ctx, QualType Ty) const;
void printPretty(raw_ostream &OS, const PrintingPolicy &Policy, QualType Ty,
                 const ASTContext *Ctx = nullptr) const;

std::string getAsString(const ASTContext &Ctx, QualType Ty) const;

APSInt &getInt() {
  assert(isInt() && "Invalid accessor")((void)0);
  return *(APSInt *)(char *)&Data;
}
const APSInt &getInt() const {
  return const_cast<APValue*>(this)->getInt();
}

/// Try to convert this value to an integral constant. This works if it's an
/// integer, null pointer, or offset from a null pointer. Returns true on
/// success.
bool toIntegralConstant(APSInt &Result, QualType SrcTy,
                        const ASTContext &Ctx) const;

APFloat &getFloat() {
  assert(isFloat() && "Invalid accessor")((void)0);
  return *(APFloat *)(char *)&Data;
}
const APFloat &getFloat() const {
  return const_cast<APValue*>(this)->getFloat();
}

APFixedPoint &getFixedPoint() {
  assert(isFixedPoint() && "Invalid accessor")((void)0);
  return *(APFixedPoint *)(char *)&Data;
}
const APFixedPoint &getFixedPoint() const {
  return const_cast<APValue *>(this)->getFixedPoint();
}

APSInt &getComplexIntReal() {
  assert(isComplexInt() && "Invalid accessor")((void)0);
  return ((ComplexAPSInt *)(char *)&Data)->Real;
}
const APSInt &getComplexIntReal() const {
  return const_cast<APValue*>(this)->getComplexIntReal();
}

APSInt &getComplexIntImag() {
  assert(isComplexInt() && "Invalid accessor")((void)0);
  return ((ComplexAPSInt *)(char *)&Data)->Imag;
}
const APSInt &getComplexIntImag() const {
  return const_cast<APValue*>(this)->getComplexIntImag();
}

APFloat &getComplexFloatReal() {
  assert(isComplexFloat() && "Invalid accessor")((void)0);
  return ((ComplexAPFloat *)(char *)&Data)->Real;
}
const APFloat &getComplexFloatReal() const {
  return const_cast<APValue*>(this)->getComplexFloatReal();
}

APFloat &getComplexFloatImag() {
  assert(isComplexFloat() && "Invalid accessor")((void)0);
  return ((ComplexAPFloat *)(char *)&Data)->Imag;
}
const APFloat &getComplexFloatImag() const {
  return const_cast<APValue*>(this)->getComplexFloatImag();
}

const LValueBase getLValueBase() const;
CharUnits &getLValueOffset();
const CharUnits &getLValueOffset() const {
  return const_cast<APValue*>(this)->getLValueOffset();
}
bool isLValueOnePastTheEnd() const;
bool hasLValuePath() const;
ArrayRef<LValuePathEntry> getLValuePath() const;
unsigned getLValueCallIndex() const;
unsigned getLValueVersion() const;
bool isNullPointer() const;

APValue &getVectorElt(unsigned I) {
  assert(isVector() && "Invalid accessor")((void)0);
  assert(I < getVectorLength() && "Index out of range")((void)0);
  return ((Vec *)(char *)&Data)->Elts[I];
}
const APValue &getVectorElt(unsigned I) const {
  return const_cast<APValue*>(this)->getVectorElt(I);
}
unsigned getVectorLength() const {
  assert(isVector() && "Invalid accessor")((void)0);
  return ((const Vec *)(const void *)&Data)->NumElts;
}

APValue &getArrayInitializedElt(unsigned I) {
  assert(isArray() && "Invalid accessor")((void)0);
  assert(I < getArrayInitializedElts() && "Index out of range")((void)0);
  return ((Arr *)(char *)&Data)->Elts[I];
}
const APValue &getArrayInitializedElt(unsigned I) const {
  return const_cast<APValue*>(this)->getArrayInitializedElt(I);
}
bool hasArrayFiller() const {
  return getArrayInitializedElts() != getArraySize();
}
APValue &getArrayFiller() {
  assert(isArray() && "Invalid accessor")((void)0);
  assert(hasArrayFiller() && "No array filler")((void)0);
  return ((Arr *)(char *)&Data)->Elts[getArrayInitializedElts()];
}
const APValue &getArrayFiller() const {
  return const_cast<APValue*>(this)->getArrayFiller();
}
unsigned getArrayInitializedElts() const {
  assert(isArray() && "Invalid accessor")((void)0);
  return ((const Arr *)(const void *)&Data)->NumElts;
}
unsigned getArraySize() const {
  assert(isArray() && "Invalid accessor")((void)0);
  return ((const Arr *)(const void *)&Data)->ArrSize;
}

unsigned getStructNumBases() const {
  assert(isStruct() && "Invalid accessor")((void)0);
  return ((const StructData *)(const char *)&Data)->NumBases;
}
unsigned getStructNumFields() const {
  assert(isStruct() && "Invalid accessor")((void)0);
  return ((const StructData *)(const char *)&Data)->NumFields;
}
APValue &getStructBase(unsigned i) {
  assert(isStruct() && "Invalid accessor")((void)0);
  assert(i < getStructNumBases() && "base class index OOB")((void)0);
  return ((StructData *)(char *)&Data)->Elts[i];
}
APValue &getStructField(unsigned i) {
  assert(isStruct() && "Invalid accessor")((void)0);
  assert(i < getStructNumFields() && "field index OOB")((void)0);
  return ((StructData *)(char *)&Data)->Elts[getStructNumBases() + i];
}
const APValue &getStructBase(unsigned i) const {
  return const_cast<APValue*>(this)->getStructBase(i);
}
const APValue &getStructField(unsigned i) const {
  return const_cast<APValue*>(this)->getStructField(i);
}

const FieldDecl *getUnionField() const {
  assert(isUnion() && "Invalid accessor")((void)0);
  return ((const UnionData *)(const char *)&Data)->Field;
}
APValue &getUnionValue() {
  assert(isUnion() && "Invalid accessor")((void)0);
  return *((UnionData *)(char *)&Data)->Value;
}
const APValue &getUnionValue() const {
  return const_cast<APValue*>(this)->getUnionValue();
}

const ValueDecl *getMemberPointerDecl() const;
bool isMemberPointerToDerivedMember() const;
ArrayRef<const CXXRecordDecl*> getMemberPointerPath() const;

const AddrLabelExpr* getAddrLabelDiffLHS() const {
  assert(isAddrLabelDiff() && "Invalid accessor")((void)0);
  return ((const AddrLabelDiffData *)(const char *)&Data)->LHSExpr;
}
const AddrLabelExpr* getAddrLabelDiffRHS() const {
  assert(isAddrLabelDiff() && "Invalid accessor")((void)0);
  return ((const AddrLabelDiffData *)(const char *)&Data)->RHSExpr;
}

void setInt(APSInt I) {
  assert(isInt() && "Invalid accessor")((void)0);
  *(APSInt *)(char *)&Data = std::move(I);
}
void setFloat(APFloat F) {
  assert(isFloat() && "Invalid accessor")((void)0);
  *(APFloat *)(char *)&Data = std::move(F);
}
void setFixedPoint(APFixedPoint FX) {
  assert(isFixedPoint() && "Invalid accessor")((void)0);
  *(APFixedPoint *)(char *)&Data = std::move(FX);
}
void setVector(const APValue *E, unsigned N) {
  MutableArrayRef<APValue> InternalElts = setVectorUninit(N);
  for (unsigned i = 0; i != N; ++i)
    InternalElts[i] = E[i];
}
void setComplexInt(APSInt R, APSInt I) {
  assert(R.getBitWidth() == I.getBitWidth() &&((void)0)
         "Invalid complex int (type mismatch).")((void)0);
  assert(isComplexInt() && "Invalid accessor")((void)0);
  ((ComplexAPSInt *)(char *)&Data)->Real = std::move(R);
  ((ComplexAPSInt *)(char *)&Data)->Imag = std::move(I);
}
void setComplexFloat(APFloat R, APFloat I) {
  assert(&R.getSemantics() == &I.getSemantics() &&((void)0)
         "Invalid complex float (type mismatch).")((void)0);
  assert(isComplexFloat() && "Invalid accessor")((void)0);
  ((ComplexAPFloat *)(char *)&Data)->Real = std::move(R);
  ((ComplexAPFloat *)(char *)&Data)->Imag = std::move(I);
}
void setLValue(LValueBase B, const CharUnits &O, NoLValuePath,
               bool IsNullPtr);
void setLValue(LValueBase B, const CharUnits &O,
               ArrayRef<LValuePathEntry> Path, bool OnePastTheEnd,
               bool IsNullPtr);
void setUnion(const FieldDecl *Field, const APValue &Value);
void setAddrLabelDiff(const AddrLabelExpr* LHSExpr,
                      const AddrLabelExpr* RHSExpr) {
  ((AddrLabelDiffData *)(char *)&Data)->LHSExpr = LHSExpr;
  ((AddrLabelDiffData *)(char *)&Data)->RHSExpr = RHSExpr;
}

623private:
void DestroyDataAndMakeUninit();
void MakeInt() {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)&Data) APSInt(1);
  Kind = Int;
}
void MakeFloat() {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) APFloat(0.0);
  Kind = Float;
}
void MakeFixedPoint(APFixedPoint &&FX) {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) APFixedPoint(std::move(FX));
  Kind = FixedPoint;
}
void MakeVector() {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) Vec();
  Kind = Vector;
}
void MakeComplexInt() {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) ComplexAPSInt();
  Kind = ComplexInt;
}
void MakeComplexFloat() {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) ComplexAPFloat();
  Kind = ComplexFloat;
}
void MakeLValue();
void MakeArray(unsigned InitElts, unsigned Size);
void MakeStruct(unsigned B, unsigned M) {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) StructData(B, M);
  Kind = Struct;
}
void MakeUnion() {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) UnionData();
  Kind = Union;
}
void MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
                       ArrayRef<const CXXRecordDecl*> Path);
void MakeAddrLabelDiff() {
  assert(isAbsent() && "Bad state change")((void)0);
  new ((void *)(char *)&Data) AddrLabelDiffData();
  Kind = AddrLabelDiff;
}

675private:
/// The following functions are used as part of initialization, during
/// deserialization and importing. Reserve the space so that it can be
/// filled in by those steps.
MutableArrayRef<APValue> setVectorUninit(unsigned N) {
  assert(isVector() && "Invalid accessor")((void)0);
  Vec *V = ((Vec *)(char *)&Data);
  V->Elts = new APValue[N];
  V->NumElts = N;
  return {V->Elts, V->NumElts};
}
MutableArrayRef<LValuePathEntry>
setLValueUninit(LValueBase B, const CharUnits &O, unsigned Size,
                bool OnePastTheEnd, bool IsNullPtr);
MutableArrayRef<const CXXRecordDecl *>
setMemberPointerUninit(const ValueDecl *Member, bool IsDerivedMember,
                       unsigned Size);
692};

694} // end namespace clang.

696namespace llvm {
697template<> struct DenseMapInfo<clang::APValue::LValueBase> {
static clang::APValue::LValueBase getEmptyKey();
static clang::APValue::LValueBase getTombstoneKey();
static unsigned getHashValue(const clang::APValue::LValueBase &Base);
static bool isEqual(const clang::APValue::LValueBase &LHS,
                    const clang::APValue::LValueBase &RHS);
703};
704}

706#endif

←

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include/llvm/ADT/PointerUnion.h

→

1//===- llvm/ADT/PointerUnion.h - Discriminated Union of 2 Ptrs --*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the PointerUnion class, which is a discriminated union of
10// pointer types.
11//
12//===----------------------------------------------------------------------===//
13 
14#ifndef LLVM_ADT_POINTERUNION_H
15#define LLVM_ADT_POINTERUNION_H
16 
17#include "llvm/ADT/DenseMapInfo.h"
18#include "llvm/ADT/PointerIntPair.h"
19#include "llvm/Support/PointerLikeTypeTraits.h"
20#include <cassert>
21#include <cstddef>
22#include <cstdint>
23 
24namespace llvm {
25 
26template <typename T> struct PointerUnionTypeSelectorReturn {
27  using Return = T;
28};
29 
30/// Get a type based on whether two types are the same or not.
31///
32/// For:
33///
34/// \code
35///   using Ret = typename PointerUnionTypeSelector<T1, T2, EQ, NE>::Return;
36/// \endcode
37///
38/// Ret will be EQ type if T1 is same as T2 or NE type otherwise.
39template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
40struct PointerUnionTypeSelector {
41  using Return = typename PointerUnionTypeSelectorReturn<RET_NE>::Return;
42};
43 
44template <typename T, typename RET_EQ, typename RET_NE>
45struct PointerUnionTypeSelector<T, T, RET_EQ, RET_NE> {
46  using Return = typename PointerUnionTypeSelectorReturn<RET_EQ>::Return;
47};
48 
49template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
50struct PointerUnionTypeSelectorReturn<
51    PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>> {
52  using Return =
53      typename PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>::Return;
54};
55 
56namespace pointer_union_detail {
57  /// Determine the number of bits required to store integers with values < n.
58  /// This is ceil(log2(n)).
59  constexpr int bitsRequired(unsigned n) {
60    return n > 1 ? 1 + bitsRequired((n + 1) / 2) : 0;
61  }
62 
63  template <typename... Ts> constexpr int lowBitsAvailable() {
64    return std::min<int>({PointerLikeTypeTraits<Ts>::NumLowBitsAvailable...});
65  }
66 
67  /// Find the index of a type in a list of types. TypeIndex<T, Us...>::Index
68  /// is the index of T in Us, or sizeof...(Us) if T does not appear in the
69  /// list.
70  template <typename T, typename ...Us> struct TypeIndex;
71  template <typename T, typename ...Us> struct TypeIndex<T, T, Us...> {
72    static constexpr int Index = 0;
73  };
74  template <typename T, typename U, typename... Us>
75  struct TypeIndex<T, U, Us...> {
76    static constexpr int Index = 1 + TypeIndex<T, Us...>::Index;
77  };
78  template <typename T> struct TypeIndex<T> {
79    static constexpr int Index = 0;
80  };
81 
82  /// Find the first type in a list of types.
83  template <typename T, typename...> struct GetFirstType {
84    using type = T;
85  };
86 
87  /// Provide PointerLikeTypeTraits for void* that is used by PointerUnion
88  /// for the template arguments.
89  template <typename ...PTs> class PointerUnionUIntTraits {
90  public:
91    static inline void *getAsVoidPointer(void *P) { return P; }
92    static inline void *getFromVoidPointer(void *P) { return P; }
93    static constexpr int NumLowBitsAvailable = lowBitsAvailable<PTs...>();
94  };
95 
96  template <typename Derived, typename ValTy, int I, typename ...Types>
97  class PointerUnionMembers;
98 
99  template <typename Derived, typename ValTy, int I>
100  class PointerUnionMembers<Derived, ValTy, I> {
101  protected:
102    ValTy Val;
103    PointerUnionMembers() = default;
104    PointerUnionMembers(ValTy Val) : Val(Val) {}
105 
106    friend struct PointerLikeTypeTraits<Derived>;
107  };
108 
109  template <typename Derived, typename ValTy, int I, typename Type,
110            typename ...Types>
111  class PointerUnionMembers<Derived, ValTy, I, Type, Types...>
112      : public PointerUnionMembers<Derived, ValTy, I + 1, Types...> {
113    using Base = PointerUnionMembers<Derived, ValTy, I + 1, Types...>;
114  public:
115    using Base::Base;
116    PointerUnionMembers() = default;
117    PointerUnionMembers(Type V)
118        : Base(ValTy(const_cast<void *>(
119                         PointerLikeTypeTraits<Type>::getAsVoidPointer(V)),
120                     I)) {}
121 
122    using Base::operator=;
123    Derived &operator=(Type V) {
124      this->Val = ValTy(
125          const_cast<void *>(PointerLikeTypeTraits<Type>::getAsVoidPointer(V)),
126          I);
127      return static_cast<Derived &>(*this);
128    };
129  };
130}
131 
132/// A discriminated union of two or more pointer types, with the discriminator
133/// in the low bit of the pointer.
134///
135/// This implementation is extremely efficient in space due to leveraging the
136/// low bits of the pointer, while exposing a natural and type-safe API.
137///
138/// Common use patterns would be something like this:
139///    PointerUnion<int*, float*> P;
140///    P = (int*)0;
141///    printf("%d %d", P.is<int*>(), P.is<float*>());  // prints "1 0"
142///    X = P.get<int*>();     // ok.
143///    Y = P.get<float*>();   // runtime assertion failure.
144///    Z = P.get<double*>();  // compile time failure.
145///    P = (float*)0;
146///    Y = P.get<float*>();   // ok.
147///    X = P.get<int*>();     // runtime assertion failure.
148template <typename... PTs>
149class PointerUnion
150    : public pointer_union_detail::PointerUnionMembers<
151          PointerUnion<PTs...>,
152          PointerIntPair<
153              void *, pointer_union_detail::bitsRequired(sizeof...(PTs)), int,
154              pointer_union_detail::PointerUnionUIntTraits<PTs...>>,
155          0, PTs...> {
156  // The first type is special because we want to directly cast a pointer to a
157  // default-initialized union to a pointer to the first type. But we don't
158  // want PointerUnion to be a 'template <typename First, typename ...Rest>'
159  // because it's much more convenient to have a name for the whole pack. So
160  // split off the first type here.
161  using First = typename pointer_union_detail::GetFirstType<PTs...>::type;
162  using Base = typename PointerUnion::PointerUnionMembers;
163 
164public:
165  PointerUnion() = default;
166 
167  PointerUnion(std::nullptr_t) : PointerUnion() {}
168  using Base::Base;
169 
170  /// Test if the pointer held in the union is null, regardless of
171  /// which type it is.
172  bool isNull() const { return !this->Val.getPointer(); }
173 
174  explicit operator bool() const { return !isNull(); }
175 
176  /// Test if the Union currently holds the type matching T.
177  template <typename T> bool is() const {
178    constexpr int Index = pointer_union_detail::TypeIndex<T, PTs...>::Index;
179    static_assert(Index < sizeof...(PTs),
180                  "PointerUnion::is<T> given type not in the union");
181    return this->Val.getInt() == Index;
74
←
Assuming the condition is false→
75
←
Returning zero, which participates in a condition later→
182  }
183 
184  /// Returns the value of the specified pointer type.
185  ///
186  /// If the specified pointer type is incorrect, assert.
187  template <typename T> T get() const {
188    assert(is<T>() && "Invalid accessor called")((void)0);
189    return PointerLikeTypeTraits<T>::getFromVoidPointer(this->Val.getPointer());
190  }
191 
192  /// Returns the current pointer if it is of the specified pointer type,
193  /// otherwise returns null.
194  template <typename T> T dyn_cast() const {
195    if (is<T>())
73
←
Calling 'PointerUnion::is'→
76
←
Returning from 'PointerUnion::is'→
77
←
Taking false branch→
196      return get<T>();
197    return T();
78
←
Returning null pointer, which participates in a condition later→
198  }
199 
200  /// If the union is set to the first pointer type get an address pointing to
201  /// it.
202  First const *getAddrOfPtr1() const {
203    return const_cast<PointerUnion *>(this)->getAddrOfPtr1();
204  }
205 
206  /// If the union is set to the first pointer type get an address pointing to
207  /// it.
208  First *getAddrOfPtr1() {
209    assert(is<First>() && "Val is not the first pointer")((void)0);
210    assert(((void)0)
211        PointerLikeTypeTraits<First>::getAsVoidPointer(get<First>()) ==((void)0)
212            this->Val.getPointer() &&((void)0)
213        "Can't get the address because PointerLikeTypeTraits changes the ptr")((void)0);
214    return const_cast<First *>(
215        reinterpret_cast<const First *>(this->Val.getAddrOfPointer()));
216  }
217 
218  /// Assignment from nullptr which just clears the union.
219  const PointerUnion &operator=(std::nullptr_t) {
220    this->Val.initWithPointer(nullptr);
221    return *this;
222  }
223 
224  /// Assignment from elements of the union.
225  using Base::operator=;
226 
227  void *getOpaqueValue() const { return this->Val.getOpaqueValue(); }
228  static inline PointerUnion getFromOpaqueValue(void *VP) {
229    PointerUnion V;
230    V.Val = decltype(V.Val)::getFromOpaqueValue(VP);
231    return V;
232  }
233};
234 
235template <typename ...PTs>
236bool operator==(PointerUnion<PTs...> lhs, PointerUnion<PTs...> rhs) {
237  return lhs.getOpaqueValue() == rhs.getOpaqueValue();
238}
239 
240template <typename ...PTs>
241bool operator!=(PointerUnion<PTs...> lhs, PointerUnion<PTs...> rhs) {
242  return lhs.getOpaqueValue() != rhs.getOpaqueValue();
243}
244 
245template <typename ...PTs>
246bool operator<(PointerUnion<PTs...> lhs, PointerUnion<PTs...> rhs) {
247  return lhs.getOpaqueValue() < rhs.getOpaqueValue();
248}
249 
250// Teach SmallPtrSet that PointerUnion is "basically a pointer", that has
251// # low bits available = min(PT1bits,PT2bits)-1.
252template <typename ...PTs>
253struct PointerLikeTypeTraits<PointerUnion<PTs...>> {
254  static inline void *getAsVoidPointer(const PointerUnion<PTs...> &P) {
255    return P.getOpaqueValue();
256  }
257 
258  static inline PointerUnion<PTs...> getFromVoidPointer(void *P) {
259    return PointerUnion<PTs...>::getFromOpaqueValue(P);
260  }
261 
262  // The number of bits available are the min of the pointer types minus the
263  // bits needed for the discriminator.
264  static constexpr int NumLowBitsAvailable = PointerLikeTypeTraits<decltype(
265      PointerUnion<PTs...>::Val)>::NumLowBitsAvailable;
266};
267 
268// Teach DenseMap how to use PointerUnions as keys.
269template <typename ...PTs> struct DenseMapInfo<PointerUnion<PTs...>> {
270  using Union = PointerUnion<PTs...>;
271  using FirstInfo =
272      DenseMapInfo<typename pointer_union_detail::GetFirstType<PTs...>::type>;
273 
274  static inline Union getEmptyKey() { return Union(FirstInfo::getEmptyKey()); }
275 
276  static inline Union getTombstoneKey() {
277    return Union(FirstInfo::getTombstoneKey());
278  }
279 
280  static unsigned getHashValue(const Union &UnionVal) {
281    intptr_t key = (intptr_t)UnionVal.getOpaqueValue();
282    return DenseMapInfo<intptr_t>::getHashValue(key);
283  }
284 
285  static bool isEqual(const Union &LHS, const Union &RHS) {
286    return LHS == RHS;
287  }
288};
289 
290} // end namespace llvm
291 
292#endif // LLVM_ADT_POINTERUNION_H

←

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include/llvm/ADT/SmallVector.h

1//===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the SmallVector class.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_ADT_SMALLVECTOR_H
14#define LLVM_ADT_SMALLVECTOR_H

16#include "llvm/ADT/iterator_range.h"
17#include "llvm/Support/Compiler.h"
18#include "llvm/Support/ErrorHandling.h"
19#include "llvm/Support/MemAlloc.h"
20#include "llvm/Support/type_traits.h"
21#include <algorithm>
22#include <cassert>
23#include <cstddef>
24#include <cstdlib>
25#include <cstring>
26#include <functional>
27#include <initializer_list>
28#include <iterator>
29#include <limits>
30#include <memory>
31#include <new>
32#include <type_traits>
33#include <utility>

35namespace llvm {

37/// This is all the stuff common to all SmallVectors.
38///
39/// The template parameter specifies the type which should be used to hold the
40/// Size and Capacity of the SmallVector, so it can be adjusted.
41/// Using 32 bit size is desirable to shrink the size of the SmallVector.
42/// Using 64 bit size is desirable for cases like SmallVector<char>, where a
43/// 32 bit size would limit the vector to ~4GB. SmallVectors are used for
44/// buffering bitcode output - which can exceed 4GB.
45template <class Size_T> class SmallVectorBase {
46protected:
void *BeginX;
Size_T Size = 0, Capacity;

/// The maximum value of the Size_T used.
static constexpr size_t SizeTypeMax() {
  return std::numeric_limits<Size_T>::max();
}

SmallVectorBase() = delete;
SmallVectorBase(void *FirstEl, size_t TotalCapacity)
    : BeginX(FirstEl), Capacity(TotalCapacity) {}

/// This is a helper for \a grow() that's out of line to reduce code
/// duplication.  This function will report a fatal error if it can't grow at
/// least to \p MinSize.
void *mallocForGrow(size_t MinSize, size_t TSize, size_t &NewCapacity);

/// This is an implementation of the grow() method which only works
/// on POD-like data types and is out of line to reduce code duplication.
/// This function will report a fatal error if it cannot increase capacity.
void grow_pod(void *FirstEl, size_t MinSize, size_t TSize);

69public:
size_t size() const { return Size; }
size_t capacity() const { return Capacity; }

LLVM_NODISCARD[[clang::warn_unused_result]] bool empty() const { return !Size; }
98
←
Assuming field 'Size' is not equal to 0, which participates in a condition later→
99
←
Returning zero, which participates in a condition later→

/// Set the array size to \p N, which the current array must have enough
/// capacity for.
///
/// This does not construct or destroy any elements in the vector.
///
/// Clients can use this in conjunction with capacity() to write past the end
/// of the buffer when they know that more elements are available, and only
/// update the size later. This avoids the cost of value initializing elements
/// which will only be overwritten.
void set_size(size_t N) {
  assert(N <= capacity())((void)0);
  Size = N;
}
88};

90template <class T>
91using SmallVectorSizeType =
  typename std::conditional<sizeof(T) < 4 && sizeof(void *) >= 8, uint64_t,
                            uint32_t>::type;

95/// Figure out the offset of the first element.
96template <class T, typename = void> struct SmallVectorAlignmentAndSize {
alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof(
    SmallVectorBase<SmallVectorSizeType<T>>)];
alignas(T) char FirstEl[sizeof(T)];
100};

102/// This is the part of SmallVectorTemplateBase which does not depend on whether
103/// the type T is a POD. The extra dummy template argument is used by ArrayRef
104/// to avoid unnecessarily requiring T to be complete.
105template <typename T, typename = void>
106class SmallVectorTemplateCommon
  : public SmallVectorBase<SmallVectorSizeType<T>> {
using Base = SmallVectorBase<SmallVectorSizeType<T>>;

/// Find the address of the first element.  For this pointer math to be valid
/// with small-size of 0 for T with lots of alignment, it's important that
/// SmallVectorStorage is properly-aligned even for small-size of 0.
void *getFirstEl() const {
  return const_cast<void *>(reinterpret_cast<const void *>(
      reinterpret_cast<const char *>(this) +
      offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)__builtin_offsetof(SmallVectorAlignmentAndSize<T>, FirstEl
)));
}
// Space after 'FirstEl' is clobbered, do not add any instance vars after it.

120protected:
SmallVectorTemplateCommon(size_t Size) : Base(getFirstEl(), Size) {}

void grow_pod(size_t MinSize, size_t TSize) {
  Base::grow_pod(getFirstEl(), MinSize, TSize);
}

/// Return true if this is a smallvector which has not had dynamic
/// memory allocated for it.
bool isSmall() const { return this->BeginX == getFirstEl(); }

/// Put this vector in a state of being small.
void resetToSmall() {
  this->BeginX = getFirstEl();
  this->Size = this->Capacity = 0; // FIXME: Setting Capacity to 0 is suspect.
}

/// Return true if V is an internal reference to the given range.
bool isReferenceToRange(const void *V, const void *First, const void *Last) const {
  // Use std::less to avoid UB.
  std::less<> LessThan;
  return !LessThan(V, First) && LessThan(V, Last);
}

/// Return true if V is an internal reference to this vector.
bool isReferenceToStorage(const void *V) const {
  return isReferenceToRange(V, this->begin(), this->end());
}

/// Return true if First and Last form a valid (possibly empty) range in this
/// vector's storage.
bool isRangeInStorage(const void *First, const void *Last) const {
  // Use std::less to avoid UB.
  std::less<> LessThan;
  return !LessThan(First, this->begin()) && !LessThan(Last, First) &&
         !LessThan(this->end(), Last);
}

/// Return true unless Elt will be invalidated by resizing the vector to
/// NewSize.
bool isSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
  // Past the end.
  if (LLVM_LIKELY(!isReferenceToStorage(Elt))__builtin_expect((bool)(!isReferenceToStorage(Elt)), true))
    return true;

  // Return false if Elt will be destroyed by shrinking.
  if (NewSize <= this->size())
    return Elt < this->begin() + NewSize;

  // Return false if we need to grow.
  return NewSize <= this->capacity();
}

/// Check whether Elt will be invalidated by resizing the vector to NewSize.
void assertSafeToReferenceAfterResize(const void *Elt, size_t NewSize) {
  assert(isSafeToReferenceAfterResize(Elt, NewSize) &&((void)0)
         "Attempting to reference an element of the vector in an operation "((void)0)
         "that invalidates it")((void)0);
}

/// Check whether Elt will be invalidated by increasing the size of the
/// vector by N.
void assertSafeToAdd(const void *Elt, size_t N = 1) {
  this->assertSafeToReferenceAfterResize(Elt, this->size() + N);
}

/// Check whether any part of the range will be invalidated by clearing.
void assertSafeToReferenceAfterClear(const T *From, const T *To) {
  if (From == To)
    return;
  this->assertSafeToReferenceAfterResize(From, 0);
  this->assertSafeToReferenceAfterResize(To - 1, 0);
}
template <
    class ItTy,
    std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
                     bool> = false>
void assertSafeToReferenceAfterClear(ItTy, ItTy) {}

/// Check whether any part of the range will be invalidated by growing.
void assertSafeToAddRange(const T *From, const T *To) {
  if (From == To)
    return;
  this->assertSafeToAdd(From, To - From);
  this->assertSafeToAdd(To - 1, To - From);
}
template <
    class ItTy,
    std::enable_if_t<!std::is_same<std::remove_const_t<ItTy>, T *>::value,
                     bool> = false>
void assertSafeToAddRange(ItTy, ItTy) {}

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
template <class U>
static const T *reserveForParamAndGetAddressImpl(U *This, const T &Elt,
                                                 size_t N) {
  size_t NewSize = This->size() + N;
  if (LLVM_LIKELY(NewSize <= This->capacity())__builtin_expect((bool)(NewSize <= This->capacity()), true
))
    return &Elt;

  bool ReferencesStorage = false;
  int64_t Index = -1;
  if (!U::TakesParamByValue) {
    if (LLVM_UNLIKELY(This->isReferenceToStorage(&Elt))__builtin_expect((bool)(This->isReferenceToStorage(&Elt
)), false)) {
      ReferencesStorage = true;
      Index = &Elt - This->begin();
    }
  }
  This->grow(NewSize);
  return ReferencesStorage ? This->begin() + Index : &Elt;
}

233public:
using size_type = size_t;
using difference_type = ptrdiff_t;
using value_type = T;
using iterator = T *;
using const_iterator = const T *;

using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = std::reverse_iterator<iterator>;

using reference = T &;
using const_reference = const T &;
using pointer = T *;
using const_pointer = const T *;

using Base::capacity;
using Base::empty;
using Base::size;

// forward iterator creation methods.
iterator begin() { return (iterator)this->BeginX; }
const_iterator begin() const { return (const_iterator)this->BeginX; }
iterator end() { return begin() + size(); }
const_iterator end() const { return begin() + size(); }

// reverse iterator creation methods.
reverse_iterator rbegin()            { return reverse_iterator(end()); }
const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
reverse_iterator rend()              { return reverse_iterator(begin()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin());}

size_type size_in_bytes() const { return size() * sizeof(T); }
size_type max_size() const {
  return std::min(this->SizeTypeMax(), size_type(-1) / sizeof(T));
}

size_t capacity_in_bytes() const { return capacity() * sizeof(T); }

/// Return a pointer to the vector's buffer, even if empty().
pointer data() { return pointer(begin()); }
/// Return a pointer to the vector's buffer, even if empty().
const_pointer data() const { return const_pointer(begin()); }

reference operator[](size_type idx) {
  assert(idx < size())((void)0);
  return begin()[idx];
}
const_reference operator[](size_type idx) const {
  assert(idx < size())((void)0);
  return begin()[idx];
}

reference front() {
  assert(!empty())((void)0);
  return begin()[0];
}
const_reference front() const {
  assert(!empty())((void)0);
  return begin()[0];
}

reference back() {
  assert(!empty())((void)0);
  return end()[-1];
}
const_reference back() const {
  assert(!empty())((void)0);
  return end()[-1];
}
302};

304/// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put
305/// method implementations that are designed to work with non-trivial T's.
306///
307/// We approximate is_trivially_copyable with trivial move/copy construction and
308/// trivial destruction. While the standard doesn't specify that you're allowed
309/// copy these types with memcpy, there is no way for the type to observe this.
310/// This catches the important case of std::pair<POD, POD>, which is not
311/// trivially assignable.
312template <typename T, bool = (is_trivially_copy_constructible<T>::value) &&
                           (is_trivially_move_constructible<T>::value) &&
                           std::is_trivially_destructible<T>::value>
315class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
friend class SmallVectorTemplateCommon<T>;

318protected:
static constexpr bool TakesParamByValue = false;
using ValueParamT = const T &;

SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}

static void destroy_range(T *S, T *E) {
  while (S != E) {
    --E;
    E->~T();
  }
}

/// Move the range [I, E) into the uninitialized memory starting with "Dest",
/// constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_move(It1 I, It1 E, It2 Dest) {
  std::uninitialized_copy(std::make_move_iterator(I),
                          std::make_move_iterator(E), Dest);
}

/// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
/// constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
  std::uninitialized_copy(I, E, Dest);
}

/// Grow the allocated memory (without initializing new elements), doubling
/// the size of the allocated memory. Guarantees space for at least one more
/// element, or MinSize more elements if specified.
void grow(size_t MinSize = 0);

/// Create a new allocation big enough for \p MinSize and pass back its size
/// in \p NewCapacity. This is the first section of \a grow().
T *mallocForGrow(size_t MinSize, size_t &NewCapacity) {
  return static_cast<T *>(
      SmallVectorBase<SmallVectorSizeType<T>>::mallocForGrow(
          MinSize, sizeof(T), NewCapacity));
}

/// Move existing elements over to the new allocation \p NewElts, the middle
/// section of \a grow().
void moveElementsForGrow(T *NewElts);

/// Transfer ownership of the allocation, finishing up \a grow().
void takeAllocationForGrow(T *NewElts, size_t NewCapacity);

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
  return this->reserveForParamAndGetAddressImpl(this, Elt, N);
}

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
  return const_cast<T *>(
      this->reserveForParamAndGetAddressImpl(this, Elt, N));
}

static T &&forward_value_param(T &&V) { return std::move(V); }
static const T &forward_value_param(const T &V) { return V; }

void growAndAssign(size_t NumElts, const T &Elt) {
  // Grow manually in case Elt is an internal reference.
  size_t NewCapacity;
  T *NewElts = mallocForGrow(NumElts, NewCapacity);
  std::uninitialized_fill_n(NewElts, NumElts, Elt);
  this->destroy_range(this->begin(), this->end());
  takeAllocationForGrow(NewElts, NewCapacity);
  this->set_size(NumElts);
}

template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
  // Grow manually in case one of Args is an internal reference.
  size_t NewCapacity;
  T *NewElts = mallocForGrow(0, NewCapacity);
  ::new ((void *)(NewElts + this->size())) T(std::forward<ArgTypes>(Args)...);
  moveElementsForGrow(NewElts);
  takeAllocationForGrow(NewElts, NewCapacity);
  this->set_size(this->size() + 1);
  return this->back();
}

403public:
void push_back(const T &Elt) {
  const T *EltPtr = reserveForParamAndGetAddress(Elt);
  ::new ((void *)this->end()) T(*EltPtr);
  this->set_size(this->size() + 1);
}

void push_back(T &&Elt) {
  T *EltPtr = reserveForParamAndGetAddress(Elt);
  ::new ((void *)this->end()) T(::std::move(*EltPtr));
  this->set_size(this->size() + 1);
}

void pop_back() {
  this->set_size(this->size() - 1);
  this->end()->~T();
}
420};

422// Define this out-of-line to dissuade the C++ compiler from inlining it.
423template <typename T, bool TriviallyCopyable>
424void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) {
size_t NewCapacity;
T *NewElts = mallocForGrow(MinSize, NewCapacity);
moveElementsForGrow(NewElts);
takeAllocationForGrow(NewElts, NewCapacity);
429}

431// Define this out-of-line to dissuade the C++ compiler from inlining it.
432template <typename T, bool TriviallyCopyable>
433void SmallVectorTemplateBase<T, TriviallyCopyable>::moveElementsForGrow(
  T *NewElts) {
// Move the elements over.
this->uninitialized_move(this->begin(), this->end(), NewElts);

// Destroy the original elements.
destroy_range(this->begin(), this->end());
440}

442// Define this out-of-line to dissuade the C++ compiler from inlining it.
443template <typename T, bool TriviallyCopyable>
444void SmallVectorTemplateBase<T, TriviallyCopyable>::takeAllocationForGrow(
  T *NewElts, size_t NewCapacity) {
// If this wasn't grown from the inline copy, deallocate the old space.
if (!this->isSmall())
  free(this->begin());

this->BeginX = NewElts;
this->Capacity = NewCapacity;
452}

454/// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put
455/// method implementations that are designed to work with trivially copyable
456/// T's. This allows using memcpy in place of copy/move construction and
457/// skipping destruction.
458template <typename T>
459class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
friend class SmallVectorTemplateCommon<T>;

462protected:
/// True if it's cheap enough to take parameters by value. Doing so avoids
/// overhead related to mitigations for reference invalidation.
static constexpr bool TakesParamByValue = sizeof(T) <= 2 * sizeof(void *);

/// Either const T& or T, depending on whether it's cheap enough to take
/// parameters by value.
using ValueParamT =
    typename std::conditional<TakesParamByValue, T, const T &>::type;

SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}

// No need to do a destroy loop for POD's.
static void destroy_range(T *, T *) {}

/// Move the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template<typename It1, typename It2>
static void uninitialized_move(It1 I, It1 E, It2 Dest) {
  // Just do a copy.
  uninitialized_copy(I, E, Dest);
}

/// Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
  // Arbitrary iterator types; just use the basic implementation.
  std::uninitialized_copy(I, E, Dest);
}

/// Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
template <typename T1, typename T2>
static void uninitialized_copy(
    T1 *I, T1 *E, T2 *Dest,
    std::enable_if_t<std::is_same<typename std::remove_const<T1>::type,
                                  T2>::value> * = nullptr) {
  // Use memcpy for PODs iterated by pointers (which includes SmallVector
  // iterators): std::uninitialized_copy optimizes to memmove, but we can
  // use memcpy here. Note that I and E are iterators and thus might be
  // invalid for memcpy if they are equal.
  if (I != E)
    memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
}

/// Double the size of the allocated memory, guaranteeing space for at
/// least one more element or MinSize if specified.
void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); }

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
const T *reserveForParamAndGetAddress(const T &Elt, size_t N = 1) {
  return this->reserveForParamAndGetAddressImpl(this, Elt, N);
}

/// Reserve enough space to add one element, and return the updated element
/// pointer in case it was a reference to the storage.
T *reserveForParamAndGetAddress(T &Elt, size_t N = 1) {
  return const_cast<T *>(
      this->reserveForParamAndGetAddressImpl(this, Elt, N));
}

/// Copy \p V or return a reference, depending on \a ValueParamT.
static ValueParamT forward_value_param(ValueParamT V) { return V; }

void growAndAssign(size_t NumElts, T Elt) {
  // Elt has been copied in case it's an internal reference, side-stepping
  // reference invalidation problems without losing the realloc optimization.
  this->set_size(0);
  this->grow(NumElts);
  std::uninitialized_fill_n(this->begin(), NumElts, Elt);
  this->set_size(NumElts);
}

template <typename... ArgTypes> T &growAndEmplaceBack(ArgTypes &&... Args) {
  // Use push_back with a copy in case Args has an internal reference,
  // side-stepping reference invalidation problems without losing the realloc
  // optimization.
  push_back(T(std::forward<ArgTypes>(Args)...));
  return this->back();
}

545public:
void push_back(ValueParamT Elt) {
  const T *EltPtr = reserveForParamAndGetAddress(Elt);
  memcpy(reinterpret_cast<void *>(this->end()), EltPtr, sizeof(T));
  this->set_size(this->size() + 1);
}

void pop_back() { this->set_size(this->size() - 1); }
553};

555/// This class consists of common code factored out of the SmallVector class to
556/// reduce code duplication based on the SmallVector 'N' template parameter.
557template <typename T>
558class SmallVectorImpl : public SmallVectorTemplateBase<T> {
using SuperClass = SmallVectorTemplateBase<T>;

561public:
using iterator = typename SuperClass::iterator;
using const_iterator = typename SuperClass::const_iterator;
using reference = typename SuperClass::reference;
using size_type = typename SuperClass::size_type;

567protected:
using SmallVectorTemplateBase<T>::TakesParamByValue;
using ValueParamT = typename SuperClass::ValueParamT;

// Default ctor - Initialize to empty.
explicit SmallVectorImpl(unsigned N)
    : SmallVectorTemplateBase<T>(N) {}

575public:
SmallVectorImpl(const SmallVectorImpl &) = delete;

~SmallVectorImpl() {
  // Subclass has already destructed this vector's elements.
  // If this wasn't grown from the inline copy, deallocate the old space.
  if (!this->isSmall())
    free(this->begin());
}

void clear() {
  this->destroy_range(this->begin(), this->end());
  this->Size = 0;
}

590private:
template <bool ForOverwrite> void resizeImpl(size_type N) {
  if (N < this->size()) {
    this->pop_back_n(this->size() - N);
  } else if (N > this->size()) {
    this->reserve(N);
    for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
      if (ForOverwrite)
        new (&*I) T;
      else
        new (&*I) T();
    this->set_size(N);
  }
}

605public:
void resize(size_type N) { resizeImpl<false>(N); }

/// Like resize, but \ref T is POD, the new values won't be initialized.
void resize_for_overwrite(size_type N) { resizeImpl<true>(N); }

void resize(size_type N, ValueParamT NV) {
  if (N == this->size())
    return;

  if (N < this->size()) {
    this->pop_back_n(this->size() - N);
    return;
  }

  // N > this->size(). Defer to append.
  this->append(N - this->size(), NV);
}

void reserve(size_type N) {
  if (this->capacity() < N)
    this->grow(N);
}

void pop_back_n(size_type NumItems) {
  assert(this->size() >= NumItems)((void)0);
  this->destroy_range(this->end() - NumItems, this->end());
  this->set_size(this->size() - NumItems);
}

LLVM_NODISCARD[[clang::warn_unused_result]] T pop_back_val() {
  T Result = ::std::move(this->back());
  this->pop_back();
  return Result;
}

void swap(SmallVectorImpl &RHS);

/// Add the specified range to the end of the SmallVector.
template <typename in_iter,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<in_iter>::iterator_category,
              std::input_iterator_tag>::value>>
void append(in_iter in_start, in_iter in_end) {
  this->assertSafeToAddRange(in_start, in_end);
  size_type NumInputs = std::distance(in_start, in_end);
  this->reserve(this->size() + NumInputs);
  this->uninitialized_copy(in_start, in_end, this->end());
  this->set_size(this->size() + NumInputs);
}

/// Append \p NumInputs copies of \p Elt to the end.
void append(size_type NumInputs, ValueParamT Elt) {
  const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumInputs);
  std::uninitialized_fill_n(this->end(), NumInputs, *EltPtr);
  this->set_size(this->size() + NumInputs);
}

void append(std::initializer_list<T> IL) {
  append(IL.begin(), IL.end());
}

void append(const SmallVectorImpl &RHS) { append(RHS.begin(), RHS.end()); }

void assign(size_type NumElts, ValueParamT Elt) {
  // Note that Elt could be an internal reference.
  if (NumElts > this->capacity()) {
    this->growAndAssign(NumElts, Elt);
    return;
  }

  // Assign over existing elements.
  std::fill_n(this->begin(), std::min(NumElts, this->size()), Elt);
  if (NumElts > this->size())
    std::uninitialized_fill_n(this->end(), NumElts - this->size(), Elt);
  else if (NumElts < this->size())
    this->destroy_range(this->begin() + NumElts, this->end());
  this->set_size(NumElts);
}

// FIXME: Consider assigning over existing elements, rather than clearing &
// re-initializing them - for all assign(...) variants.

template <typename in_iter,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<in_iter>::iterator_category,
              std::input_iterator_tag>::value>>
void assign(in_iter in_start, in_iter in_end) {
  this->assertSafeToReferenceAfterClear(in_start, in_end);
  clear();
  append(in_start, in_end);
}

void assign(std::initializer_list<T> IL) {
  clear();
  append(IL);
}

void assign(const SmallVectorImpl &RHS) { assign(RHS.begin(), RHS.end()); }

iterator erase(const_iterator CI) {
  // Just cast away constness because this is a non-const member function.
  iterator I = const_cast<iterator>(CI);

  assert(this->isReferenceToStorage(CI) && "Iterator to erase is out of bounds.")((void)0);

  iterator N = I;
  // Shift all elts down one.
  std::move(I+1, this->end(), I);
  // Drop the last elt.
  this->pop_back();
  return(N);
}

iterator erase(const_iterator CS, const_iterator CE) {
  // Just cast away constness because this is a non-const member function.
  iterator S = const_cast<iterator>(CS);
  iterator E = const_cast<iterator>(CE);

  assert(this->isRangeInStorage(S, E) && "Range to erase is out of bounds.")((void)0);

  iterator N = S;
  // Shift all elts down.
  iterator I = std::move(E, this->end(), S);
  // Drop the last elts.
  this->destroy_range(I, this->end());
  this->set_size(I - this->begin());
  return(N);
}

735private:
template <class ArgType> iterator insert_one_impl(iterator I, ArgType &&Elt) {
  // Callers ensure that ArgType is derived from T.
  static_assert(
      std::is_same<std::remove_const_t<std::remove_reference_t<ArgType>>,
                   T>::value,
      "ArgType must be derived from T!");

  if (I == this->end()) {  // Important special case for empty vector.
    this->push_back(::std::forward<ArgType>(Elt));
    return this->end()-1;
  }

  assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0);

  // Grow if necessary.
  size_t Index = I - this->begin();
  std::remove_reference_t<ArgType> *EltPtr =
      this->reserveForParamAndGetAddress(Elt);
  I = this->begin() + Index;

  ::new ((void*) this->end()) T(::std::move(this->back()));
  // Push everything else over.
  std::move_backward(I, this->end()-1, this->end());
  this->set_size(this->size() + 1);

  // If we just moved the element we're inserting, be sure to update
  // the reference (never happens if TakesParamByValue).
  static_assert(!TakesParamByValue || std::is_same<ArgType, T>::value,
                "ArgType must be 'T' when taking by value!");
  if (!TakesParamByValue && this->isReferenceToRange(EltPtr, I, this->end()))
    ++EltPtr;

  *I = ::std::forward<ArgType>(*EltPtr);
  return I;
}

772public:
iterator insert(iterator I, T &&Elt) {
  return insert_one_impl(I, this->forward_value_param(std::move(Elt)));
}

iterator insert(iterator I, const T &Elt) {
  return insert_one_impl(I, this->forward_value_param(Elt));
}

iterator insert(iterator I, size_type NumToInsert, ValueParamT Elt) {
  // Convert iterator to elt# to avoid invalidating iterator when we reserve()
  size_t InsertElt = I - this->begin();

  if (I == this->end()) {  // Important special case for empty vector.
    append(NumToInsert, Elt);
    return this->begin()+InsertElt;
  }

  assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0);

  // Ensure there is enough space, and get the (maybe updated) address of
  // Elt.
  const T *EltPtr = this->reserveForParamAndGetAddress(Elt, NumToInsert);

  // Uninvalidate the iterator.
  I = this->begin()+InsertElt;

  // If there are more elements between the insertion point and the end of the
  // range than there are being inserted, we can use a simple approach to
  // insertion.  Since we already reserved space, we know that this won't
  // reallocate the vector.
  if (size_t(this->end()-I) >= NumToInsert) {
    T *OldEnd = this->end();
    append(std::move_iterator<iterator>(this->end() - NumToInsert),
           std::move_iterator<iterator>(this->end()));

    // Copy the existing elements that get replaced.
    std::move_backward(I, OldEnd-NumToInsert, OldEnd);

    // If we just moved the element we're inserting, be sure to update
    // the reference (never happens if TakesParamByValue).
    if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
      EltPtr += NumToInsert;

    std::fill_n(I, NumToInsert, *EltPtr);
    return I;
  }

  // Otherwise, we're inserting more elements than exist already, and we're
  // not inserting at the end.

  // Move over the elements that we're about to overwrite.
  T *OldEnd = this->end();
  this->set_size(this->size() + NumToInsert);
  size_t NumOverwritten = OldEnd-I;
  this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);

  // If we just moved the element we're inserting, be sure to update
  // the reference (never happens if TakesParamByValue).
  if (!TakesParamByValue && I <= EltPtr && EltPtr < this->end())
    EltPtr += NumToInsert;

  // Replace the overwritten part.
  std::fill_n(I, NumOverwritten, *EltPtr);

  // Insert the non-overwritten middle part.
  std::uninitialized_fill_n(OldEnd, NumToInsert - NumOverwritten, *EltPtr);
  return I;
}

template <typename ItTy,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<ItTy>::iterator_category,
              std::input_iterator_tag>::value>>
iterator insert(iterator I, ItTy From, ItTy To) {
  // Convert iterator to elt# to avoid invalidating iterator when we reserve()
  size_t InsertElt = I - this->begin();

  if (I == this->end()) {  // Important special case for empty vector.
    append(From, To);
    return this->begin()+InsertElt;
  }

  assert(this->isReferenceToStorage(I) && "Insertion iterator is out of bounds.")((void)0);

  // Check that the reserve that follows doesn't invalidate the iterators.
  this->assertSafeToAddRange(From, To);

  size_t NumToInsert = std::distance(From, To);

  // Ensure there is enough space.
  reserve(this->size() + NumToInsert);

  // Uninvalidate the iterator.
  I = this->begin()+InsertElt;

  // If there are more elements between the insertion point and the end of the
  // range than there are being inserted, we can use a simple approach to
  // insertion.  Since we already reserved space, we know that this won't
  // reallocate the vector.
  if (size_t(this->end()-I) >= NumToInsert) {
    T *OldEnd = this->end();
    append(std::move_iterator<iterator>(this->end() - NumToInsert),
           std::move_iterator<iterator>(this->end()));

    // Copy the existing elements that get replaced.
    std::move_backward(I, OldEnd-NumToInsert, OldEnd);

    std::copy(From, To, I);
    return I;
  }

  // Otherwise, we're inserting more elements than exist already, and we're
  // not inserting at the end.

  // Move over the elements that we're about to overwrite.
  T *OldEnd = this->end();
  this->set_size(this->size() + NumToInsert);
  size_t NumOverwritten = OldEnd-I;
  this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);

  // Replace the overwritten part.
  for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
    *J = *From;
    ++J; ++From;
  }

  // Insert the non-overwritten middle part.
  this->uninitialized_copy(From, To, OldEnd);
  return I;
}

void insert(iterator I, std::initializer_list<T> IL) {
  insert(I, IL.begin(), IL.end());
}

template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) {
  if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity
()), false))
    return this->growAndEmplaceBack(std::forward<ArgTypes>(Args)...);

  ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
  this->set_size(this->size() + 1);
  return this->back();
}

SmallVectorImpl &operator=(const SmallVectorImpl &RHS);

SmallVectorImpl &operator=(SmallVectorImpl &&RHS);

bool operator==(const SmallVectorImpl &RHS) const {
  if (this->size() != RHS.size()) return false;
  return std::equal(this->begin(), this->end(), RHS.begin());
}
bool operator!=(const SmallVectorImpl &RHS) const {
  return !(*this == RHS);
}

bool operator<(const SmallVectorImpl &RHS) const {
  return std::lexicographical_compare(this->begin(), this->end(),
                                      RHS.begin(), RHS.end());
}
933};

935template <typename T>
936void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
if (this == &RHS) return;

// We can only avoid copying elements if neither vector is small.
if (!this->isSmall() && !RHS.isSmall()) {
  std::swap(this->BeginX, RHS.BeginX);
  std::swap(this->Size, RHS.Size);
  std::swap(this->Capacity, RHS.Capacity);
  return;
}
this->reserve(RHS.size());
RHS.reserve(this->size());

// Swap the shared elements.
size_t NumShared = this->size();
if (NumShared > RHS.size()) NumShared = RHS.size();
for (size_type i = 0; i != NumShared; ++i)
  std::swap((*this)[i], RHS[i]);

// Copy over the extra elts.
if (this->size() > RHS.size()) {
  size_t EltDiff = this->size() - RHS.size();
  this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
  RHS.set_size(RHS.size() + EltDiff);
  this->destroy_range(this->begin()+NumShared, this->end());
  this->set_size(NumShared);
} else if (RHS.size() > this->size()) {
  size_t EltDiff = RHS.size() - this->size();
  this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
  this->set_size(this->size() + EltDiff);
  this->destroy_range(RHS.begin()+NumShared, RHS.end());
  RHS.set_size(NumShared);
}
969}

971template <typename T>
972SmallVectorImpl<T> &SmallVectorImpl<T>::
operator=(const SmallVectorImpl<T> &RHS) {
// Avoid self-assignment.
if (this == &RHS) return *this;

// If we already have sufficient space, assign the common elements, then
// destroy any excess.
size_t RHSSize = RHS.size();
size_t CurSize = this->size();
if (CurSize >= RHSSize) {
  // Assign common elements.
  iterator NewEnd;
  if (RHSSize)
    NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
  else
    NewEnd = this->begin();

  // Destroy excess elements.
  this->destroy_range(NewEnd, this->end());

  // Trim.
  this->set_size(RHSSize);
  return *this;
}

// If we have to grow to have enough elements, destroy the current elements.
// This allows us to avoid copying them during the grow.
// FIXME: don't do this if they're efficiently moveable.
if (this->capacity() < RHSSize) {
  // Destroy current elements.
  this->clear();
  CurSize = 0;
  this->grow(RHSSize);
} else if (CurSize) {
  // Otherwise, use assignment for the already-constructed elements.
  std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
}

// Copy construct the new elements in place.
this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
                         this->begin()+CurSize);

// Set end.
this->set_size(RHSSize);
return *this;
1017}

1019template <typename T>
1020SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
// Avoid self-assignment.
if (this == &RHS) return *this;

// If the RHS isn't small, clear this vector and then steal its buffer.
if (!RHS.isSmall()) {
  this->destroy_range(this->begin(), this->end());
  if (!this->isSmall()) free(this->begin());
  this->BeginX = RHS.BeginX;
  this->Size = RHS.Size;
  this->Capacity = RHS.Capacity;
  RHS.resetToSmall();
  return *this;
}

// If we already have sufficient space, assign the common elements, then
// destroy any excess.
size_t RHSSize = RHS.size();
size_t CurSize = this->size();
if (CurSize >= RHSSize) {
  // Assign common elements.
  iterator NewEnd = this->begin();
  if (RHSSize)
    NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd);

  // Destroy excess elements and trim the bounds.
  this->destroy_range(NewEnd, this->end());
  this->set_size(RHSSize);

  // Clear the RHS.
  RHS.clear();

  return *this;
}

// If we have to grow to have enough elements, destroy the current elements.
// This allows us to avoid copying them during the grow.
// FIXME: this may not actually make any sense if we can efficiently move
// elements.
if (this->capacity() < RHSSize) {
  // Destroy current elements.
  this->clear();
  CurSize = 0;
  this->grow(RHSSize);
} else if (CurSize) {
  // Otherwise, use assignment for the already-constructed elements.
  std::move(RHS.begin(), RHS.begin()+CurSize, this->begin());
}

// Move-construct the new elements in place.
this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
                         this->begin()+CurSize);

// Set end.
this->set_size(RHSSize);

RHS.clear();
return *this;
1078}

1080/// Storage for the SmallVector elements.  This is specialized for the N=0 case
1081/// to avoid allocating unnecessary storage.
1082template <typename T, unsigned N>
1083struct SmallVectorStorage {
alignas(T) char InlineElts[N * sizeof(T)];
1085};

1087/// We need the storage to be properly aligned even for small-size of 0 so that
1088/// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
1089/// well-defined.
1090template <typename T> struct alignas(T) SmallVectorStorage<T, 0> {};

1092/// Forward declaration of SmallVector so that
1093/// calculateSmallVectorDefaultInlinedElements can reference
1094/// `sizeof(SmallVector<T, 0>)`.
1095template <typename T, unsigned N> class LLVM_GSL_OWNER[[gsl::Owner]] SmallVector;

1097/// Helper class for calculating the default number of inline elements for
1098/// `SmallVector<T>`.
1099///
1100/// This should be migrated to a constexpr function when our minimum
1101/// compiler support is enough for multi-statement constexpr functions.
1102template <typename T> struct CalculateSmallVectorDefaultInlinedElements {
// Parameter controlling the default number of inlined elements
// for `SmallVector<T>`.
//
// The default number of inlined elements ensures that
// 1. There is at least one inlined element.
// 2. `sizeof(SmallVector<T>) <= kPreferredSmallVectorSizeof` unless
// it contradicts 1.
static constexpr size_t kPreferredSmallVectorSizeof = 64;

// static_assert that sizeof(T) is not "too big".
//
// Because our policy guarantees at least one inlined element, it is possible
// for an arbitrarily large inlined element to allocate an arbitrarily large
// amount of inline storage. We generally consider it an antipattern for a
// SmallVector to allocate an excessive amount of inline storage, so we want
// to call attention to these cases and make sure that users are making an
// intentional decision if they request a lot of inline storage.
//
// We want this assertion to trigger in pathological cases, but otherwise
// not be too easy to hit. To accomplish that, the cutoff is actually somewhat
// larger than kPreferredSmallVectorSizeof (otherwise,
// `SmallVector<SmallVector<T>>` would be one easy way to trip it, and that
// pattern seems useful in practice).
//
// One wrinkle is that this assertion is in theory non-portable, since
// sizeof(T) is in general platform-dependent. However, we don't expect this
// to be much of an issue, because most LLVM development happens on 64-bit
// hosts, and therefore sizeof(T) is expected to *decrease* when compiled for
// 32-bit hosts, dodging the issue. The reverse situation, where development
// happens on a 32-bit host and then fails due to sizeof(T) *increasing* on a
// 64-bit host, is expected to be very rare.
static_assert(
    sizeof(T) <= 256,
    "You are trying to use a default number of inlined elements for "
    "`SmallVector<T>` but `sizeof(T)` is really big! Please use an "
    "explicit number of inlined elements with `SmallVector<T, N>` to make "
    "sure you really want that much inline storage.");

// Discount the size of the header itself when calculating the maximum inline
// bytes.
static constexpr size_t PreferredInlineBytes =
    kPreferredSmallVectorSizeof - sizeof(SmallVector<T, 0>);
static constexpr size_t NumElementsThatFit = PreferredInlineBytes / sizeof(T);
static constexpr size_t value =
    NumElementsThatFit == 0 ? 1 : NumElementsThatFit;
1148};

1150/// This is a 'vector' (really, a variable-sized array), optimized
1151/// for the case when the array is small.  It contains some number of elements
1152/// in-place, which allows it to avoid heap allocation when the actual number of
1153/// elements is below that threshold.  This allows normal "small" cases to be
1154/// fast without losing generality for large inputs.
1155///
1156/// \note
1157/// In the absence of a well-motivated choice for the number of inlined
1158/// elements \p N, it is recommended to use \c SmallVector<T> (that is,
1159/// omitting the \p N). This will choose a default number of inlined elements
1160/// reasonable for allocation on the stack (for example, trying to keep \c
1161/// sizeof(SmallVector<T>) around 64 bytes).
1162///
1163/// \warning This does not attempt to be exception safe.
1164///
1165/// \see https://llvm.org/docs/ProgrammersManual.html#llvm-adt-smallvector-h
1166template <typename T,
        unsigned N = CalculateSmallVectorDefaultInlinedElements<T>::value>
1168class LLVM_GSL_OWNER[[gsl::Owner]] SmallVector : public SmallVectorImpl<T>,
                                 SmallVectorStorage<T, N> {
1170public:
SmallVector() : SmallVectorImpl<T>(N) {}

~SmallVector() {
  // Destroy the constructed elements in the vector.
  this->destroy_range(this->begin(), this->end());
}

explicit SmallVector(size_t Size, const T &Value = T())
  : SmallVectorImpl<T>(N) {
  this->assign(Size, Value);
}

template <typename ItTy,
          typename = std::enable_if_t<std::is_convertible<
              typename std::iterator_traits<ItTy>::iterator_category,
              std::input_iterator_tag>::value>>
SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
  this->append(S, E);
}

template <typename RangeTy>
explicit SmallVector(const iterator_range<RangeTy> &R)
    : SmallVectorImpl<T>(N) {
  this->append(R.begin(), R.end());
}

SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
  this->assign(IL);
}

SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(RHS);
}

SmallVector &operator=(const SmallVector &RHS) {
  SmallVectorImpl<T>::operator=(RHS);
  return *this;
}

SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(::std::move(RHS));
}

SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
  if (!RHS.empty())
    SmallVectorImpl<T>::operator=(::std::move(RHS));
}

SmallVector &operator=(SmallVector &&RHS) {
  SmallVectorImpl<T>::operator=(::std::move(RHS));
  return *this;
}

SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
  SmallVectorImpl<T>::operator=(::std::move(RHS));
  return *this;
}

SmallVector &operator=(std::initializer_list<T> IL) {
  this->assign(IL);
  return *this;
}
1235};

1237template <typename T, unsigned N>
1238inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
return X.capacity_in_bytes();
1240}

1242/// Given a range of type R, iterate the entire range and return a
1243/// SmallVector with elements of the vector.  This is useful, for example,
1244/// when you want to iterate a range and then sort the results.
1245template <unsigned Size, typename R>
1246SmallVector<typename std::remove_const<typename std::remove_reference<
              decltype(*std::begin(std::declval<R &>()))>::type>::type,
          Size>
1249to_vector(R &&Range) {
return {std::begin(Range), std::end(Range)};
1251}

1253} // end namespace llvm

1255namespace std {

/// Implement std::swap in terms of SmallVector swap.
template<typename T>
inline void
swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
  LHS.swap(RHS);
}

/// Implement std::swap in terms of SmallVector swap.
template<typename T, unsigned N>
inline void
swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
  LHS.swap(RHS);
}

1271} // end namespace std

1273#endif // LLVM_ADT_SMALLVECTOR_H