/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include/llvm/ADT/APSInt.h

Bug Summary

File:	src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include/llvm/ADT/APSInt.h
Warning:	line 22, column 22 Assigned value is garbage or undefined

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)
      return &LB->second;
    // 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;
  }

  /// 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()),
        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)
      return false;
    if (NextCallIndex == 0) {
      // NextCallIndex has wrapped around.
      FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
      return false;
    }
    if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
      return true;
    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 Frame ? Frame->getTemporary(Call.getOrigParam(PVD), Call.Version)
                 : 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()) {
21
←
Taking false branch→
      makeComplexFloat();
      FloatReal = v.getComplexFloatReal();
      FloatImag = v.getComplexFloatImag();
    } else {
      makeComplexInt();
      IntReal = v.getComplexIntReal();
22
←
Calling implicit copy assignment operator for 'APSInt'→
      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())
  return !RD->field_empty();
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)
  return false;

// Check for special cases where there is no existing APValue to look at.
const Expr *Base = LVal.Base.dyn_cast<const Expr*>();

AccessKinds AK =
    WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read;

if (Base && !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);
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)
  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;) {
  //   -- 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())
  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());
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);
if (!RefValue) {
  Info.FFDiag(E);
  return false;
}

// Copy out the contents of the RHS object.
LValue RefLValue;
RefLValue.setFrom(Info.Ctx, *RefValue);
return handleLValueToRValueConversion(
    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))
  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);
if (MD && MD->isDefaulted() &&
    (MD->getParent()->isUnion() ||
     (MD->isTrivial() &&
      isReadByLvalueToRvalueConversion(MD->getParent())))) {
  assert(This &&((void)0)
         (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()))((void)0);
  APValue RHSValue;
  if (!handleTrivialCopy(Info, MD->getParamDecl(0), Args[0], RHSValue,
                         MD->getParent()->isUnion()))
    return false;
  if (Info.getLangOpts().CPlusPlus20 && MD->isTrivial() &&
      !HandleUnionActiveMemberChange(Info, Args[0], *This))
    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);
19
←
Calling 'ComplexExprEvaluator::Success'→
}
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))
4
←
Calling 'ExprEvaluatorBase::handleCallExpr'→
15
←
Returning from 'ExprEvaluatorBase::handleCallExpr'→
16
←
Assuming the condition is false→
17
←
Taking false branch→
    return false;
  return DerivedSuccess(Result, E);
18
←
Calling 'ExprEvaluatorBase::DerivedSuccess'→
}

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)) {
5
←
Taking true branch→
    const CXXMethodDecl *Member = nullptr;
    if (const MemberExpr *ME6.1
'ME' is null
1
'ME' is null
 = dyn_cast<MemberExpr>(Callee)) {
6
←
Assuming 'Callee' is not a 'MemberExpr'→
7
←
Taking false branch→
      // 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 *BE8.1
'BE' is null
1
'BE' is null
 = dyn_cast<BinaryOperator>(Callee)) {
8
←
Assuming 'Callee' is not a 'BinaryOperator'→
9
←
Taking false branch→
      // 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 *PDE10.1
'PDE' is non-null
1
'PDE' is non-null
 = dyn_cast<CXXPseudoDestructorExpr>(Callee)) {
10
←
Assuming 'Callee' is a 'CXXPseudoDestructorExpr'→
11
←
Taking true branch→
      if (!Info.getLangOpts().CPlusPlus20)
12
←
Assuming field 'CPlusPlus20' is not equal to 0→
13
←
Taking false branch→
        Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor);
      return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) &&
14
←
Assuming the condition is true→
             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);
20
←
Calling 'ComplexValue::setFrom'→
  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()) {
1
Control jumps to the 'default' case at line 14341→
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;
2
←
 Execution continues on line 14345→
}

return ExprEvaluatorBaseTy::VisitCallExpr(E);
3
←
Calling 'ExprEvaluatorBase::VisitCallExpr'→
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())
  return true;

Expr::EvalStatus Status;
Status.Diag = &Diags;

EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression);
Info.InConstantContext = true;
Info.CheckingPotentialConstantExpression = true;

// The constexpr VM attempts to compile all methods to bytecode here.
if (Info.EnableNewConstInterp) {
  Info.Ctx.getInterpContext().isPotentialConstantExpr(Info, FD);
  return Diags.empty();
}

const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;

// 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);
This.set({&VIE, Info.CurrentCall->Index});

ArrayRef<const Expr*> Args;

APValue Scratch;
if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
  // 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, (MD && MD->isInstance()) ? &This : nullptr,
                     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/llvm/include/llvm/ADT/APSInt.h

1//===-- llvm/ADT/APSInt.h - Arbitrary Precision Signed Int -----*- 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 implements the APSInt class, which is a simple class that
10// represents an arbitrary sized integer that knows its signedness.
11//
12//===----------------------------------------------------------------------===//

14#ifndef LLVM_ADT_APSINT_H
15#define LLVM_ADT_APSINT_H

17#include "llvm/ADT/APInt.h"

19namespace llvm {

21/// An arbitrary precision integer that knows its signedness.
22class LLVM_NODISCARD[[clang::warn_unused_result]] APSInt : public APInt {
23
←
Assigned value is garbage or undefined
bool IsUnsigned;

25public:
/// Default constructor that creates an uninitialized APInt.
explicit APSInt() : IsUnsigned(false) {}

/// Create an APSInt with the specified width, default to unsigned.
explicit APSInt(uint32_t BitWidth, bool isUnsigned = true)
 : APInt(BitWidth, 0), IsUnsigned(isUnsigned) {}

explicit APSInt(APInt I, bool isUnsigned = true)
 : APInt(std::move(I)), IsUnsigned(isUnsigned) {}

/// Construct an APSInt from a string representation.
///
/// This constructor interprets the string \p Str using the radix of 10.
/// The interpretation stops at the end of the string. The bit width of the
/// constructed APSInt is determined automatically.
///
/// \param Str the string to be interpreted.
explicit APSInt(StringRef Str);

/// Determine sign of this APSInt.
///
/// \returns true if this APSInt is negative, false otherwise
bool isNegative() const { return isSigned() && APInt::isNegative(); }

/// Determine if this APSInt Value is non-negative (>= 0)
///
/// \returns true if this APSInt is non-negative, false otherwise
bool isNonNegative() const { return !isNegative(); }

/// Determine if this APSInt Value is positive.
///
/// This tests if the value of this APSInt is positive (> 0). Note
/// that 0 is not a positive value.
///
/// \returns true if this APSInt is positive.
bool isStrictlyPositive() const { return isNonNegative() && !isNullValue(); }

APSInt &operator=(APInt RHS) {
  // Retain our current sign.
  APInt::operator=(std::move(RHS));
  return *this;
}

APSInt &operator=(uint64_t RHS) {
  // Retain our current sign.
  APInt::operator=(RHS);
  return *this;
}

// Query sign information.
bool isSigned() const { return !IsUnsigned; }
bool isUnsigned() const { return IsUnsigned; }
void setIsUnsigned(bool Val) { IsUnsigned = Val; }
void setIsSigned(bool Val) { IsUnsigned = !Val; }

/// Append this APSInt to the specified SmallString.
void toString(SmallVectorImpl<char> &Str, unsigned Radix = 10) const {
  APInt::toString(Str, Radix, isSigned());
}
using APInt::toString;

/// Get the correctly-extended \c int64_t value.
int64_t getExtValue() const {
  assert(getMinSignedBits() <= 64 && "Too many bits for int64_t")((void)0);
  return isSigned() ? getSExtValue() : getZExtValue();
}

APSInt trunc(uint32_t width) const {
  return APSInt(APInt::trunc(width), IsUnsigned);
}

APSInt extend(uint32_t width) const {
  if (IsUnsigned)
    return APSInt(zext(width), IsUnsigned);
  else
    return APSInt(sext(width), IsUnsigned);
}

APSInt extOrTrunc(uint32_t width) const {
  if (IsUnsigned)
    return APSInt(zextOrTrunc(width), IsUnsigned);
  else
    return APSInt(sextOrTrunc(width), IsUnsigned);
}

const APSInt &operator%=(const APSInt &RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  if (IsUnsigned)
    *this = urem(RHS);
  else
    *this = srem(RHS);
  return *this;
}
const APSInt &operator/=(const APSInt &RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  if (IsUnsigned)
    *this = udiv(RHS);
  else
    *this = sdiv(RHS);
  return *this;
}
APSInt operator%(const APSInt &RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return IsUnsigned ? APSInt(urem(RHS), true) : APSInt(srem(RHS), false);
}
APSInt operator/(const APSInt &RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return IsUnsigned ? APSInt(udiv(RHS), true) : APSInt(sdiv(RHS), false);
}

APSInt operator>>(unsigned Amt) const {
  return IsUnsigned ? APSInt(lshr(Amt), true) : APSInt(ashr(Amt), false);
}
APSInt& operator>>=(unsigned Amt) {
  if (IsUnsigned)
    lshrInPlace(Amt);
  else
    ashrInPlace(Amt);
  return *this;
}

inline bool operator<(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return IsUnsigned ? ult(RHS) : slt(RHS);
}
inline bool operator>(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return IsUnsigned ? ugt(RHS) : sgt(RHS);
}
inline bool operator<=(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return IsUnsigned ? ule(RHS) : sle(RHS);
}
inline bool operator>=(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return IsUnsigned ? uge(RHS) : sge(RHS);
}
inline bool operator==(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return eq(RHS);
}
inline bool operator!=(const APSInt& RHS) const {
  return !((*this) == RHS);
}

bool operator==(int64_t RHS) const {
  return compareValues(*this, get(RHS)) == 0;
}
bool operator!=(int64_t RHS) const {
  return compareValues(*this, get(RHS)) != 0;
}
bool operator<=(int64_t RHS) const {
  return compareValues(*this, get(RHS)) <= 0;
}
bool operator>=(int64_t RHS) const {
  return compareValues(*this, get(RHS)) >= 0;
}
bool operator<(int64_t RHS) const {
  return compareValues(*this, get(RHS)) < 0;
}
bool operator>(int64_t RHS) const {
  return compareValues(*this, get(RHS)) > 0;
}

// The remaining operators just wrap the logic of APInt, but retain the
// signedness information.

APSInt operator<<(unsigned Bits) const {
  return APSInt(static_cast<const APInt&>(*this) << Bits, IsUnsigned);
}
APSInt& operator<<=(unsigned Amt) {
  static_cast<APInt&>(*this) <<= Amt;
  return *this;
}

APSInt& operator++() {
  ++(static_cast<APInt&>(*this));
  return *this;
}
APSInt& operator--() {
  --(static_cast<APInt&>(*this));
  return *this;
}
APSInt operator++(int) {
  return APSInt(++static_cast<APInt&>(*this), IsUnsigned);
}
APSInt operator--(int) {
  return APSInt(--static_cast<APInt&>(*this), IsUnsigned);
}
APSInt operator-() const {
  return APSInt(-static_cast<const APInt&>(*this), IsUnsigned);
}
APSInt& operator+=(const APSInt& RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  static_cast<APInt&>(*this) += RHS;
  return *this;
}
APSInt& operator-=(const APSInt& RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  static_cast<APInt&>(*this) -= RHS;
  return *this;
}
APSInt& operator*=(const APSInt& RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  static_cast<APInt&>(*this) *= RHS;
  return *this;
}
APSInt& operator&=(const APSInt& RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  static_cast<APInt&>(*this) &= RHS;
  return *this;
}
APSInt& operator|=(const APSInt& RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  static_cast<APInt&>(*this) |= RHS;
  return *this;
}
APSInt& operator^=(const APSInt& RHS) {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  static_cast<APInt&>(*this) ^= RHS;
  return *this;
}

APSInt operator&(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return APSInt(static_cast<const APInt&>(*this) & RHS, IsUnsigned);
}

APSInt operator|(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return APSInt(static_cast<const APInt&>(*this) | RHS, IsUnsigned);
}

APSInt operator^(const APSInt &RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return APSInt(static_cast<const APInt&>(*this) ^ RHS, IsUnsigned);
}

APSInt operator*(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return APSInt(static_cast<const APInt&>(*this) * RHS, IsUnsigned);
}
APSInt operator+(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return APSInt(static_cast<const APInt&>(*this) + RHS, IsUnsigned);
}
APSInt operator-(const APSInt& RHS) const {
  assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
  return APSInt(static_cast<const APInt&>(*this) - RHS, IsUnsigned);
}
APSInt operator~() const {
  return APSInt(~static_cast<const APInt&>(*this), IsUnsigned);
}

/// Return the APSInt representing the maximum integer value with the given
/// bit width and signedness.
static APSInt getMaxValue(uint32_t numBits, bool Unsigned) {
  return APSInt(Unsigned ? APInt::getMaxValue(numBits)
                         : APInt::getSignedMaxValue(numBits), Unsigned);
}

/// Return the APSInt representing the minimum integer value with the given
/// bit width and signedness.
static APSInt getMinValue(uint32_t numBits, bool Unsigned) {
  return APSInt(Unsigned ? APInt::getMinValue(numBits)
                         : APInt::getSignedMinValue(numBits), Unsigned);
}

/// Determine if two APSInts have the same value, zero- or
/// sign-extending as needed.
static bool isSameValue(const APSInt &I1, const APSInt &I2) {
  return !compareValues(I1, I2);
}

/// Compare underlying values of two numbers.
static int compareValues(const APSInt &I1, const APSInt &I2) {
  if (I1.getBitWidth() == I2.getBitWidth() && I1.isSigned() == I2.isSigned())
    return I1.IsUnsigned ? I1.compare(I2) : I1.compareSigned(I2);

  // Check for a bit-width mismatch.
  if (I1.getBitWidth() > I2.getBitWidth())
    return compareValues(I1, I2.extend(I1.getBitWidth()));
  if (I2.getBitWidth() > I1.getBitWidth())
    return compareValues(I1.extend(I2.getBitWidth()), I2);

  // We have a signedness mismatch. Check for negative values and do an
  // unsigned compare if both are positive.
  if (I1.isSigned()) {
    assert(!I2.isSigned() && "Expected signed mismatch")((void)0);
    if (I1.isNegative())
      return -1;
  } else {
    assert(I2.isSigned() && "Expected signed mismatch")((void)0);
    if (I2.isNegative())
      return 1;
  }

  return I1.compare(I2);
}

static APSInt get(int64_t X) { return APSInt(APInt(64, X), false); }
static APSInt getUnsigned(uint64_t X) { return APSInt(APInt(64, X), true); }

/// Used to insert APSInt objects, or objects that contain APSInt objects,
/// into FoldingSets.
void Profile(FoldingSetNodeID& ID) const;
332};

334inline bool operator==(int64_t V1, const APSInt &V2) { return V2 == V1; }
335inline bool operator!=(int64_t V1, const APSInt &V2) { return V2 != V1; }
336inline bool operator<=(int64_t V1, const APSInt &V2) { return V2 >= V1; }
337inline bool operator>=(int64_t V1, const APSInt &V2) { return V2 <= V1; }
338inline bool operator<(int64_t V1, const APSInt &V2) { return V2 > V1; }
339inline bool operator>(int64_t V1, const APSInt &V2) { return V2 < V1; }

341inline raw_ostream &operator<<(raw_ostream &OS, const APSInt &I) {
I.print(OS, I.isSigned());
return OS;
344}

346/// Provide DenseMapInfo for APSInt, using the DenseMapInfo for APInt.
347template <> struct DenseMapInfo<APSInt> {
static inline APSInt getEmptyKey() {
  return APSInt(DenseMapInfo<APInt>::getEmptyKey());
}

static inline APSInt getTombstoneKey() {
  return APSInt(DenseMapInfo<APInt>::getTombstoneKey());
}

static unsigned getHashValue(const APSInt &Key) {
  return DenseMapInfo<APInt>::getHashValue(Key);
}

static bool isEqual(const APSInt &LHS, const APSInt &RHS) {
  return LHS.getBitWidth() == RHS.getBitWidth() &&
         LHS.isUnsigned() == RHS.isUnsigned() && LHS == RHS;
}
364};

366} // end namespace llvm

368#endif