/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaDecl.cpp

Bug Summary

File:	src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaDecl.cpp
Warning:	line 14480, column 29 Called C++ object pointer is null
Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaDecl.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/libclangSema/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include/clang/Sema -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../include -I /usr/src/gnu/usr.bin/clang/libclangSema/obj -I /usr/src/gnu/usr.bin/clang/libclangSema/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/libclangSema/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/libclangSema/../../../llvm/clang/lib/Sema/SemaDecl.cpp
1//===--- SemaDecl.cpp - Semantic Analysis for Declarations ----------------===//
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 semantic analysis for declarations.
10//
11//===----------------------------------------------------------------------===//

13#include "TypeLocBuilder.h"
14#include "clang/AST/ASTConsumer.h"
15#include "clang/AST/ASTContext.h"
16#include "clang/AST/ASTLambda.h"
17#include "clang/AST/CXXInheritance.h"
18#include "clang/AST/CharUnits.h"
19#include "clang/AST/CommentDiagnostic.h"
20#include "clang/AST/DeclCXX.h"
21#include "clang/AST/DeclObjC.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/EvaluatedExprVisitor.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/NonTrivialTypeVisitor.h"
27#include "clang/AST/StmtCXX.h"
28#include "clang/Basic/Builtins.h"
29#include "clang/Basic/PartialDiagnostic.h"
30#include "clang/Basic/SourceManager.h"
31#include "clang/Basic/TargetInfo.h"
32#include "clang/Lex/HeaderSearch.h" // TODO: Sema shouldn't depend on Lex
33#include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering.
34#include "clang/Lex/ModuleLoader.h" // TODO: Sema shouldn't depend on Lex
35#include "clang/Lex/Preprocessor.h" // Included for isCodeCompletionEnabled()
36#include "clang/Sema/CXXFieldCollector.h"
37#include "clang/Sema/DeclSpec.h"
38#include "clang/Sema/DelayedDiagnostic.h"
39#include "clang/Sema/Initialization.h"
40#include "clang/Sema/Lookup.h"
41#include "clang/Sema/ParsedTemplate.h"
42#include "clang/Sema/Scope.h"
43#include "clang/Sema/ScopeInfo.h"
44#include "clang/Sema/SemaInternal.h"
45#include "clang/Sema/Template.h"
46#include "llvm/ADT/SmallString.h"
47#include "llvm/ADT/Triple.h"
48#include <algorithm>
49#include <cstring>
50#include <functional>
51#include <unordered_map>

53using namespace clang;
54using namespace sema;

56Sema::DeclGroupPtrTy Sema::ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType) {
if (OwnedType) {
  Decl *Group[2] = { OwnedType, Ptr };
  return DeclGroupPtrTy::make(DeclGroupRef::Create(Context, Group, 2));
}

return DeclGroupPtrTy::make(DeclGroupRef(Ptr));
63}

65namespace {

67class TypeNameValidatorCCC final : public CorrectionCandidateCallback {
public:
 TypeNameValidatorCCC(bool AllowInvalid, bool WantClass = false,
                      bool AllowTemplates = false,
                      bool AllowNonTemplates = true)
     : AllowInvalidDecl(AllowInvalid), WantClassName(WantClass),
       AllowTemplates(AllowTemplates), AllowNonTemplates(AllowNonTemplates) {
   WantExpressionKeywords = false;
   WantCXXNamedCasts = false;
   WantRemainingKeywords = false;
}

bool ValidateCandidate(const TypoCorrection &candidate) override {
  if (NamedDecl *ND = candidate.getCorrectionDecl()) {
    if (!AllowInvalidDecl && ND->isInvalidDecl())
      return false;

    if (getAsTypeTemplateDecl(ND))
      return AllowTemplates;

    bool IsType = isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND);
    if (!IsType)
      return false;

    if (AllowNonTemplates)
      return true;

    // An injected-class-name of a class template (specialization) is valid
    // as a template or as a non-template.
    if (AllowTemplates) {
      auto *RD = dyn_cast<CXXRecordDecl>(ND);
      if (!RD || !RD->isInjectedClassName())
        return false;
      RD = cast<CXXRecordDecl>(RD->getDeclContext());
      return RD->getDescribedClassTemplate() ||
             isa<ClassTemplateSpecializationDecl>(RD);
    }

    return false;
  }

  return !WantClassName && candidate.isKeyword();
}

std::unique_ptr<CorrectionCandidateCallback> clone() override {
  return std::make_unique<TypeNameValidatorCCC>(*this);
}

private:
bool AllowInvalidDecl;
bool WantClassName;
bool AllowTemplates;
bool AllowNonTemplates;
120};

122} // end anonymous namespace

124/// Determine whether the token kind starts a simple-type-specifier.
125bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
switch (Kind) {
// FIXME: Take into account the current language when deciding whether a
// token kind is a valid type specifier
case tok::kw_short:
case tok::kw_long:
case tok::kw___int64:
case tok::kw___int128:
case tok::kw_signed:
case tok::kw_unsigned:
case tok::kw_void:
case tok::kw_char:
case tok::kw_int:
case tok::kw_half:
case tok::kw_float:
case tok::kw_double:
case tok::kw___bf16:
case tok::kw__Float16:
case tok::kw___float128:
case tok::kw_wchar_t:
case tok::kw_bool:
case tok::kw___underlying_type:
case tok::kw___auto_type:
  return true;

case tok::annot_typename:
case tok::kw_char16_t:
case tok::kw_char32_t:
case tok::kw_typeof:
case tok::annot_decltype:
case tok::kw_decltype:
  return getLangOpts().CPlusPlus;

case tok::kw_char8_t:
  return getLangOpts().Char8;

default:
  break;
}

return false;
166}

168namespace {
169enum class UnqualifiedTypeNameLookupResult {
NotFound,
FoundNonType,
FoundType
173};
174} // end anonymous namespace

176/// Tries to perform unqualified lookup of the type decls in bases for
177/// dependent class.
178/// \return \a NotFound if no any decls is found, \a FoundNotType if found not a
179/// type decl, \a FoundType if only type decls are found.
180static UnqualifiedTypeNameLookupResult
181lookupUnqualifiedTypeNameInBase(Sema &S, const IdentifierInfo &II,
                              SourceLocation NameLoc,
                              const CXXRecordDecl *RD) {
if (!RD->hasDefinition())
  return UnqualifiedTypeNameLookupResult::NotFound;
// Look for type decls in base classes.
UnqualifiedTypeNameLookupResult FoundTypeDecl =
    UnqualifiedTypeNameLookupResult::NotFound;
for (const auto &Base : RD->bases()) {
  const CXXRecordDecl *BaseRD = nullptr;
  if (auto *BaseTT = Base.getType()->getAs<TagType>())
    BaseRD = BaseTT->getAsCXXRecordDecl();
  else if (auto *TST = Base.getType()->getAs<TemplateSpecializationType>()) {
    // Look for type decls in dependent base classes that have known primary
    // templates.
    if (!TST || !TST->isDependentType())
      continue;
    auto *TD = TST->getTemplateName().getAsTemplateDecl();
    if (!TD)
      continue;
    if (auto *BasePrimaryTemplate =
        dyn_cast_or_null<CXXRecordDecl>(TD->getTemplatedDecl())) {
      if (BasePrimaryTemplate->getCanonicalDecl() != RD->getCanonicalDecl())
        BaseRD = BasePrimaryTemplate;
      else if (auto *CTD = dyn_cast<ClassTemplateDecl>(TD)) {
        if (const ClassTemplatePartialSpecializationDecl *PS =
                CTD->findPartialSpecialization(Base.getType()))
          if (PS->getCanonicalDecl() != RD->getCanonicalDecl())
            BaseRD = PS;
      }
    }
  }
  if (BaseRD) {
    for (NamedDecl *ND : BaseRD->lookup(&II)) {
      if (!isa<TypeDecl>(ND))
        return UnqualifiedTypeNameLookupResult::FoundNonType;
      FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
    }
    if (FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound) {
      switch (lookupUnqualifiedTypeNameInBase(S, II, NameLoc, BaseRD)) {
      case UnqualifiedTypeNameLookupResult::FoundNonType:
        return UnqualifiedTypeNameLookupResult::FoundNonType;
      case UnqualifiedTypeNameLookupResult::FoundType:
        FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
        break;
      case UnqualifiedTypeNameLookupResult::NotFound:
        break;
      }
    }
  }
}

return FoundTypeDecl;
234}

236static ParsedType recoverFromTypeInKnownDependentBase(Sema &S,
                                                    const IdentifierInfo &II,
                                                    SourceLocation NameLoc) {
// Lookup in the parent class template context, if any.
const CXXRecordDecl *RD = nullptr;
UnqualifiedTypeNameLookupResult FoundTypeDecl =
    UnqualifiedTypeNameLookupResult::NotFound;
for (DeclContext *DC = S.CurContext;
     DC && FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound;
     DC = DC->getParent()) {
  // Look for type decls in dependent base classes that have known primary
  // templates.
  RD = dyn_cast<CXXRecordDecl>(DC);
  if (RD && RD->getDescribedClassTemplate())
    FoundTypeDecl = lookupUnqualifiedTypeNameInBase(S, II, NameLoc, RD);
}
if (FoundTypeDecl != UnqualifiedTypeNameLookupResult::FoundType)
  return nullptr;

// We found some types in dependent base classes.  Recover as if the user
// wrote 'typename MyClass::II' instead of 'II'.  We'll fully resolve the
// lookup during template instantiation.
S.Diag(NameLoc, diag::ext_found_in_dependent_base) << &II;

ASTContext &Context = S.Context;
auto *NNS = NestedNameSpecifier::Create(Context, nullptr, false,
                                        cast<Type>(Context.getRecordType(RD)));
QualType T = Context.getDependentNameType(ETK_Typename, NNS, &II);

CXXScopeSpec SS;
SS.MakeTrivial(Context, NNS, SourceRange(NameLoc));

TypeLocBuilder Builder;
DependentNameTypeLoc DepTL = Builder.push<DependentNameTypeLoc>(T);
DepTL.setNameLoc(NameLoc);
DepTL.setElaboratedKeywordLoc(SourceLocation());
DepTL.setQualifierLoc(SS.getWithLocInContext(Context));
return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
274}

276/// If the identifier refers to a type name within this scope,
277/// return the declaration of that type.
278///
279/// This routine performs ordinary name lookup of the identifier II
280/// within the given scope, with optional C++ scope specifier SS, to
281/// determine whether the name refers to a type. If so, returns an
282/// opaque pointer (actually a QualType) corresponding to that
283/// type. Otherwise, returns NULL.
284ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
                           Scope *S, CXXScopeSpec *SS,
                           bool isClassName, bool HasTrailingDot,
                           ParsedType ObjectTypePtr,
                           bool IsCtorOrDtorName,
                           bool WantNontrivialTypeSourceInfo,
                           bool IsClassTemplateDeductionContext,
                           IdentifierInfo **CorrectedII) {
// FIXME: Consider allowing this outside C++1z mode as an extension.
bool AllowDeducedTemplate = IsClassTemplateDeductionContext &&
                            getLangOpts().CPlusPlus17 && !IsCtorOrDtorName &&
                            !isClassName && !HasTrailingDot;

// Determine where we will perform name lookup.
DeclContext *LookupCtx = nullptr;
if (ObjectTypePtr) {
  QualType ObjectType = ObjectTypePtr.get();
  if (ObjectType->isRecordType())
    LookupCtx = computeDeclContext(ObjectType);
} else if (SS && SS->isNotEmpty()) {
  LookupCtx = computeDeclContext(*SS, false);

  if (!LookupCtx) {
    if (isDependentScopeSpecifier(*SS)) {
      // C++ [temp.res]p3:
      //   A qualified-id that refers to a type and in which the
      //   nested-name-specifier depends on a template-parameter (14.6.2)
      //   shall be prefixed by the keyword typename to indicate that the
      //   qualified-id denotes a type, forming an
      //   elaborated-type-specifier (7.1.5.3).
      //
      // We therefore do not perform any name lookup if the result would
      // refer to a member of an unknown specialization.
      if (!isClassName && !IsCtorOrDtorName)
        return nullptr;

      // We know from the grammar that this name refers to a type,
      // so build a dependent node to describe the type.
      if (WantNontrivialTypeSourceInfo)
        return ActOnTypenameType(S, SourceLocation(), *SS, II, NameLoc).get();

      NestedNameSpecifierLoc QualifierLoc = SS->getWithLocInContext(Context);
      QualType T = CheckTypenameType(ETK_None, SourceLocation(), QualifierLoc,
                                     II, NameLoc);
      return ParsedType::make(T);
    }

    return nullptr;
  }

  if (!LookupCtx->isDependentContext() &&
      RequireCompleteDeclContext(*SS, LookupCtx))
    return nullptr;
}

// FIXME: LookupNestedNameSpecifierName isn't the right kind of
// lookup for class-names.
LookupNameKind Kind = isClassName ? LookupNestedNameSpecifierName :
                                    LookupOrdinaryName;
LookupResult Result(*this, &II, NameLoc, Kind);
if (LookupCtx) {
  // Perform "qualified" name lookup into the declaration context we
  // computed, which is either the type of the base of a member access
  // expression or the declaration context associated with a prior
  // nested-name-specifier.
  LookupQualifiedName(Result, LookupCtx);

  if (ObjectTypePtr && Result.empty()) {
    // C++ [basic.lookup.classref]p3:
    //   If the unqualified-id is ~type-name, the type-name is looked up
    //   in the context of the entire postfix-expression. If the type T of
    //   the object expression is of a class type C, the type-name is also
    //   looked up in the scope of class C. At least one of the lookups shall
    //   find a name that refers to (possibly cv-qualified) T.
    LookupName(Result, S);
  }
} else {
  // Perform unqualified name lookup.
  LookupName(Result, S);

  // For unqualified lookup in a class template in MSVC mode, look into
  // dependent base classes where the primary class template is known.
  if (Result.empty() && getLangOpts().MSVCCompat && (!SS || SS->isEmpty())) {
    if (ParsedType TypeInBase =
            recoverFromTypeInKnownDependentBase(*this, II, NameLoc))
      return TypeInBase;
  }
}

NamedDecl *IIDecl = nullptr;
switch (Result.getResultKind()) {
case LookupResult::NotFound:
case LookupResult::NotFoundInCurrentInstantiation:
  if (CorrectedII) {
    TypeNameValidatorCCC CCC(/*AllowInvalid=*/true, isClassName,
                             AllowDeducedTemplate);
    TypoCorrection Correction = CorrectTypo(Result.getLookupNameInfo(), Kind,
                                            S, SS, CCC, CTK_ErrorRecovery);
    IdentifierInfo *NewII = Correction.getCorrectionAsIdentifierInfo();
    TemplateTy Template;
    bool MemberOfUnknownSpecialization;
    UnqualifiedId TemplateName;
    TemplateName.setIdentifier(NewII, NameLoc);
    NestedNameSpecifier *NNS = Correction.getCorrectionSpecifier();
    CXXScopeSpec NewSS, *NewSSPtr = SS;
    if (SS && NNS) {
      NewSS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
      NewSSPtr = &NewSS;
    }
    if (Correction && (NNS || NewII != &II) &&
        // Ignore a correction to a template type as the to-be-corrected
        // identifier is not a template (typo correction for template names
        // is handled elsewhere).
        !(getLangOpts().CPlusPlus && NewSSPtr &&
          isTemplateName(S, *NewSSPtr, false, TemplateName, nullptr, false,
                         Template, MemberOfUnknownSpecialization))) {
      ParsedType Ty = getTypeName(*NewII, NameLoc, S, NewSSPtr,
                                  isClassName, HasTrailingDot, ObjectTypePtr,
                                  IsCtorOrDtorName,
                                  WantNontrivialTypeSourceInfo,
                                  IsClassTemplateDeductionContext);
      if (Ty) {
        diagnoseTypo(Correction,
                     PDiag(diag::err_unknown_type_or_class_name_suggest)
                       << Result.getLookupName() << isClassName);
        if (SS && NNS)
          SS->MakeTrivial(Context, NNS, SourceRange(NameLoc));
        *CorrectedII = NewII;
        return Ty;
      }
    }
  }
  // If typo correction failed or was not performed, fall through
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case LookupResult::FoundOverloaded:
case LookupResult::FoundUnresolvedValue:
  Result.suppressDiagnostics();
  return nullptr;

case LookupResult::Ambiguous:
  // Recover from type-hiding ambiguities by hiding the type.  We'll
  // do the lookup again when looking for an object, and we can
  // diagnose the error then.  If we don't do this, then the error
  // about hiding the type will be immediately followed by an error
  // that only makes sense if the identifier was treated like a type.
  if (Result.getAmbiguityKind() == LookupResult::AmbiguousTagHiding) {
    Result.suppressDiagnostics();
    return nullptr;
  }

  // Look to see if we have a type anywhere in the list of results.
  for (LookupResult::iterator Res = Result.begin(), ResEnd = Result.end();
       Res != ResEnd; ++Res) {
    NamedDecl *RealRes = (*Res)->getUnderlyingDecl();
    if (isa<TypeDecl, ObjCInterfaceDecl, UnresolvedUsingIfExistsDecl>(
            RealRes) ||
        (AllowDeducedTemplate && getAsTypeTemplateDecl(RealRes))) {
      if (!IIDecl ||
          // Make the selection of the recovery decl deterministic.
          RealRes->getLocation() < IIDecl->getLocation())
        IIDecl = RealRes;
    }
  }

  if (!IIDecl) {
    // None of the entities we found is a type, so there is no way
    // to even assume that the result is a type. In this case, don't
    // complain about the ambiguity. The parser will either try to
    // perform this lookup again (e.g., as an object name), which
    // will produce the ambiguity, or will complain that it expected
    // a type name.
    Result.suppressDiagnostics();
    return nullptr;
  }

  // We found a type within the ambiguous lookup; diagnose the
  // ambiguity and then return that type. This might be the right
  // answer, or it might not be, but it suppresses any attempt to
  // perform the name lookup again.
  break;

case LookupResult::Found:
  IIDecl = Result.getFoundDecl();
  break;
}

assert(IIDecl && "Didn't find decl")((void)0);

QualType T;
if (TypeDecl *TD = dyn_cast<TypeDecl>(IIDecl)) {
  // C++ [class.qual]p2: A lookup that would find the injected-class-name
  // instead names the constructors of the class, except when naming a class.
  // This is ill-formed when we're not actually forming a ctor or dtor name.
  auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
  auto *FoundRD = dyn_cast<CXXRecordDecl>(TD);
  if (!isClassName && !IsCtorOrDtorName && LookupRD && FoundRD &&
      FoundRD->isInjectedClassName() &&
      declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
    Diag(NameLoc, diag::err_out_of_line_qualified_id_type_names_constructor)
        << &II << /*Type*/1;

  DiagnoseUseOfDecl(IIDecl, NameLoc);

  T = Context.getTypeDeclType(TD);
  MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
} else if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(IIDecl)) {
  (void)DiagnoseUseOfDecl(IDecl, NameLoc);
  if (!HasTrailingDot)
    T = Context.getObjCInterfaceType(IDecl);
} else if (auto *UD = dyn_cast<UnresolvedUsingIfExistsDecl>(IIDecl)) {
  (void)DiagnoseUseOfDecl(UD, NameLoc);
  // Recover with 'int'
  T = Context.IntTy;
} else if (AllowDeducedTemplate) {
  if (auto *TD = getAsTypeTemplateDecl(IIDecl))
    T = Context.getDeducedTemplateSpecializationType(TemplateName(TD),
                                                     QualType(), false);
}

if (T.isNull()) {
  // If it's not plausibly a type, suppress diagnostics.
  Result.suppressDiagnostics();
  return nullptr;
}

// NOTE: avoid constructing an ElaboratedType(Loc) if this is a
// constructor or destructor name (in such a case, the scope specifier
// will be attached to the enclosing Expr or Decl node).
if (SS && SS->isNotEmpty() && !IsCtorOrDtorName &&
    !isa<ObjCInterfaceDecl, UnresolvedUsingIfExistsDecl>(IIDecl)) {
  if (WantNontrivialTypeSourceInfo) {
    // Construct a type with type-source information.
    TypeLocBuilder Builder;
    Builder.pushTypeSpec(T).setNameLoc(NameLoc);

    T = getElaboratedType(ETK_None, *SS, T);
    ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
    ElabTL.setElaboratedKeywordLoc(SourceLocation());
    ElabTL.setQualifierLoc(SS->getWithLocInContext(Context));
    return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
  } else {
    T = getElaboratedType(ETK_None, *SS, T);
  }
}

return ParsedType::make(T);
530}

532// Builds a fake NNS for the given decl context.
533static NestedNameSpecifier *
534synthesizeCurrentNestedNameSpecifier(ASTContext &Context, DeclContext *DC) {
for (;; DC = DC->getLookupParent()) {
  DC = DC->getPrimaryContext();
  auto *ND = dyn_cast<NamespaceDecl>(DC);
  if (ND && !ND->isInline() && !ND->isAnonymousNamespace())
    return NestedNameSpecifier::Create(Context, nullptr, ND);
  else if (auto *RD = dyn_cast<CXXRecordDecl>(DC))
    return NestedNameSpecifier::Create(Context, nullptr, RD->isTemplateDecl(),
                                       RD->getTypeForDecl());
  else if (isa<TranslationUnitDecl>(DC))
    return NestedNameSpecifier::GlobalSpecifier(Context);
}
llvm_unreachable("something isn't in TU scope?")__builtin_unreachable();
547}

549/// Find the parent class with dependent bases of the innermost enclosing method
550/// context. Do not look for enclosing CXXRecordDecls directly, or we will end
551/// up allowing unqualified dependent type names at class-level, which MSVC
552/// correctly rejects.
553static const CXXRecordDecl *
554findRecordWithDependentBasesOfEnclosingMethod(const DeclContext *DC) {
for (; DC && DC->isDependentContext(); DC = DC->getLookupParent()) {
  DC = DC->getPrimaryContext();
  if (const auto *MD = dyn_cast<CXXMethodDecl>(DC))
    if (MD->getParent()->hasAnyDependentBases())
      return MD->getParent();
}
return nullptr;
562}

564ParsedType Sema::ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
                                        SourceLocation NameLoc,
                                        bool IsTemplateTypeArg) {
assert(getLangOpts().MSVCCompat && "shouldn't be called in non-MSVC mode")((void)0);

NestedNameSpecifier *NNS = nullptr;
if (IsTemplateTypeArg && getCurScope()->isTemplateParamScope()) {
  // If we weren't able to parse a default template argument, delay lookup
  // until instantiation time by making a non-dependent DependentTypeName. We
  // pretend we saw a NestedNameSpecifier referring to the current scope, and
  // lookup is retried.
  // FIXME: This hurts our diagnostic quality, since we get errors like "no
  // type named 'Foo' in 'current_namespace'" when the user didn't write any
  // name specifiers.
  NNS = synthesizeCurrentNestedNameSpecifier(Context, CurContext);
  Diag(NameLoc, diag::ext_ms_delayed_template_argument) << &II;
} else if (const CXXRecordDecl *RD =
               findRecordWithDependentBasesOfEnclosingMethod(CurContext)) {
  // Build a DependentNameType that will perform lookup into RD at
  // instantiation time.
  NNS = NestedNameSpecifier::Create(Context, nullptr, RD->isTemplateDecl(),
                                    RD->getTypeForDecl());

  // Diagnose that this identifier was undeclared, and retry the lookup during
  // template instantiation.
  Diag(NameLoc, diag::ext_undeclared_unqual_id_with_dependent_base) << &II
                                                                    << RD;
} else {
  // This is not a situation that we should recover from.
  return ParsedType();
}

QualType T = Context.getDependentNameType(ETK_None, NNS, &II);

// Build type location information.  We synthesized the qualifier, so we have
// to build a fake NestedNameSpecifierLoc.
NestedNameSpecifierLocBuilder NNSLocBuilder;
NNSLocBuilder.MakeTrivial(Context, NNS, SourceRange(NameLoc));
NestedNameSpecifierLoc QualifierLoc = NNSLocBuilder.getWithLocInContext(Context);

TypeLocBuilder Builder;
DependentNameTypeLoc DepTL = Builder.push<DependentNameTypeLoc>(T);
DepTL.setNameLoc(NameLoc);
DepTL.setElaboratedKeywordLoc(SourceLocation());
DepTL.setQualifierLoc(QualifierLoc);
return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
610}

612/// isTagName() - This method is called *for error recovery purposes only*
613/// to determine if the specified name is a valid tag name ("struct foo").  If
614/// so, this returns the TST for the tag corresponding to it (TST_enum,
615/// TST_union, TST_struct, TST_interface, TST_class).  This is used to diagnose
616/// cases in C where the user forgot to specify the tag.
617DeclSpec::TST Sema::isTagName(IdentifierInfo &II, Scope *S) {
// Do a tag name lookup in this scope.
LookupResult R(*this, &II, SourceLocation(), LookupTagName);
LookupName(R, S, false);
R.suppressDiagnostics();
if (R.getResultKind() == LookupResult::Found)
  if (const TagDecl *TD = R.getAsSingle<TagDecl>()) {
    switch (TD->getTagKind()) {
    case TTK_Struct: return DeclSpec::TST_struct;
    case TTK_Interface: return DeclSpec::TST_interface;
    case TTK_Union:  return DeclSpec::TST_union;
    case TTK_Class:  return DeclSpec::TST_class;
    case TTK_Enum:   return DeclSpec::TST_enum;
    }
  }

return DeclSpec::TST_unspecified;
634}

636/// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
637/// if a CXXScopeSpec's type is equal to the type of one of the base classes
638/// then downgrade the missing typename error to a warning.
639/// This is needed for MSVC compatibility; Example:
640/// @code
641/// template<class T> class A {
642/// public:
643///   typedef int TYPE;
644/// };
645/// template<class T> class B : public A<T> {
646/// public:
647///   A<T>::TYPE a; // no typename required because A<T> is a base class.
648/// };
649/// @endcode
650bool Sema::isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S) {
if (CurContext->isRecord()) {
  if (SS->getScopeRep()->getKind() == NestedNameSpecifier::Super)
    return true;

  const Type *Ty = SS->getScopeRep()->getAsType();

  CXXRecordDecl *RD = cast<CXXRecordDecl>(CurContext);
  for (const auto &Base : RD->bases())
    if (Ty && Context.hasSameUnqualifiedType(QualType(Ty, 1), Base.getType()))
      return true;
  return S->isFunctionPrototypeScope();
}
return CurContext->isFunctionOrMethod() || S->isFunctionPrototypeScope();
664}

666void Sema::DiagnoseUnknownTypeName(IdentifierInfo *&II,
                                 SourceLocation IILoc,
                                 Scope *S,
                                 CXXScopeSpec *SS,
                                 ParsedType &SuggestedType,
                                 bool IsTemplateName) {
// Don't report typename errors for editor placeholders.
if (II->isEditorPlaceholder())
  return;
// We don't have anything to suggest (yet).
SuggestedType = nullptr;

// There may have been a typo in the name of the type. Look up typo
// results, in case we have something that we can suggest.
TypeNameValidatorCCC CCC(/*AllowInvalid=*/false, /*WantClass=*/false,
                         /*AllowTemplates=*/IsTemplateName,
                         /*AllowNonTemplates=*/!IsTemplateName);
if (TypoCorrection Corrected =
        CorrectTypo(DeclarationNameInfo(II, IILoc), LookupOrdinaryName, S, SS,
                    CCC, CTK_ErrorRecovery)) {
  // FIXME: Support error recovery for the template-name case.
  bool CanRecover = !IsTemplateName;
  if (Corrected.isKeyword()) {
    // We corrected to a keyword.
    diagnoseTypo(Corrected,
                 PDiag(IsTemplateName ? diag::err_no_template_suggest
                                      : diag::err_unknown_typename_suggest)
                     << II);
    II = Corrected.getCorrectionAsIdentifierInfo();
  } else {
    // We found a similarly-named type or interface; suggest that.
    if (!SS || !SS->isSet()) {
      diagnoseTypo(Corrected,
                   PDiag(IsTemplateName ? diag::err_no_template_suggest
                                        : diag::err_unknown_typename_suggest)
                       << II, CanRecover);
    } else if (DeclContext *DC = computeDeclContext(*SS, false)) {
      std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
      bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
                              II->getName().equals(CorrectedStr);
      diagnoseTypo(Corrected,
                   PDiag(IsTemplateName
                             ? diag::err_no_member_template_suggest
                             : diag::err_unknown_nested_typename_suggest)
                       << II << DC << DroppedSpecifier << SS->getRange(),
                   CanRecover);
    } else {
      llvm_unreachable("could not have corrected a typo here")__builtin_unreachable();
    }

    if (!CanRecover)
      return;

    CXXScopeSpec tmpSS;
    if (Corrected.getCorrectionSpecifier())
      tmpSS.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
                        SourceRange(IILoc));
    // FIXME: Support class template argument deduction here.
    SuggestedType =
        getTypeName(*Corrected.getCorrectionAsIdentifierInfo(), IILoc, S,
                    tmpSS.isSet() ? &tmpSS : SS, false, false, nullptr,
                    /*IsCtorOrDtorName=*/false,
                    /*WantNontrivialTypeSourceInfo=*/true);
  }
  return;
}

if (getLangOpts().CPlusPlus && !IsTemplateName) {
  // See if II is a class template that the user forgot to pass arguments to.
  UnqualifiedId Name;
  Name.setIdentifier(II, IILoc);
  CXXScopeSpec EmptySS;
  TemplateTy TemplateResult;
  bool MemberOfUnknownSpecialization;
  if (isTemplateName(S, SS ? *SS : EmptySS, /*hasTemplateKeyword=*/false,
                     Name, nullptr, true, TemplateResult,
                     MemberOfUnknownSpecialization) == TNK_Type_template) {
    diagnoseMissingTemplateArguments(TemplateResult.get(), IILoc);
    return;
  }
}

// FIXME: Should we move the logic that tries to recover from a missing tag
// (struct, union, enum) from Parser::ParseImplicitInt here, instead?

if (!SS || (!SS->isSet() && !SS->isInvalid()))
  Diag(IILoc, IsTemplateName ? diag::err_no_template
                             : diag::err_unknown_typename)
      << II;
else if (DeclContext *DC = computeDeclContext(*SS, false))
  Diag(IILoc, IsTemplateName ? diag::err_no_member_template
                             : diag::err_typename_nested_not_found)
      << II << DC << SS->getRange();
else if (SS->isValid() && SS->getScopeRep()->containsErrors()) {
  SuggestedType =
      ActOnTypenameType(S, SourceLocation(), *SS, *II, IILoc).get();
} else if (isDependentScopeSpecifier(*SS)) {
  unsigned DiagID = diag::err_typename_missing;
  if (getLangOpts().MSVCCompat && isMicrosoftMissingTypename(SS, S))
    DiagID = diag::ext_typename_missing;

  Diag(SS->getRange().getBegin(), DiagID)
    << SS->getScopeRep() << II->getName()
    << SourceRange(SS->getRange().getBegin(), IILoc)
    << FixItHint::CreateInsertion(SS->getRange().getBegin(), "typename ");
  SuggestedType = ActOnTypenameType(S, SourceLocation(),
                                    *SS, *II, IILoc).get();
} else {
  assert(SS && SS->isInvalid() &&((void)0)
         "Invalid scope specifier has already been diagnosed")((void)0);
}
777}

779/// Determine whether the given result set contains either a type name
780/// or
781static bool isResultTypeOrTemplate(LookupResult &R, const Token &NextToken) {
bool CheckTemplate = R.getSema().getLangOpts().CPlusPlus &&
                     NextToken.is(tok::less);

for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
  if (isa<TypeDecl>(*I) || isa<ObjCInterfaceDecl>(*I))
    return true;

  if (CheckTemplate && isa<TemplateDecl>(*I))
    return true;
}

return false;
794}

796static bool isTagTypeWithMissingTag(Sema &SemaRef, LookupResult &Result,
                                  Scope *S, CXXScopeSpec &SS,
                                  IdentifierInfo *&Name,
                                  SourceLocation NameLoc) {
LookupResult R(SemaRef, Name, NameLoc, Sema::LookupTagName);
SemaRef.LookupParsedName(R, S, &SS);
if (TagDecl *Tag = R.getAsSingle<TagDecl>()) {
  StringRef FixItTagName;
  switch (Tag->getTagKind()) {
    case TTK_Class:
      FixItTagName = "class ";
      break;

    case TTK_Enum:
      FixItTagName = "enum ";
      break;

    case TTK_Struct:
      FixItTagName = "struct ";
      break;

    case TTK_Interface:
      FixItTagName = "__interface ";
      break;

    case TTK_Union:
      FixItTagName = "union ";
      break;
  }

  StringRef TagName = FixItTagName.drop_back();
  SemaRef.Diag(NameLoc, diag::err_use_of_tag_name_without_tag)
    << Name << TagName << SemaRef.getLangOpts().CPlusPlus
    << FixItHint::CreateInsertion(NameLoc, FixItTagName);

  for (LookupResult::iterator I = Result.begin(), IEnd = Result.end();
       I != IEnd; ++I)
    SemaRef.Diag((*I)->getLocation(), diag::note_decl_hiding_tag_type)
      << Name << TagName;

  // Replace lookup results with just the tag decl.
  Result.clear(Sema::LookupTagName);
  SemaRef.LookupParsedName(Result, S, &SS);
  return true;
}

return false;
843}

845/// Build a ParsedType for a simple-type-specifier with a nested-name-specifier.
846static ParsedType buildNestedType(Sema &S, CXXScopeSpec &SS,
                                QualType T, SourceLocation NameLoc) {
ASTContext &Context = S.Context;

TypeLocBuilder Builder;
Builder.pushTypeSpec(T).setNameLoc(NameLoc);

T = S.getElaboratedType(ETK_None, SS, T);
ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
ElabTL.setElaboratedKeywordLoc(SourceLocation());
ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
858}

860Sema::NameClassification Sema::ClassifyName(Scope *S, CXXScopeSpec &SS,
                                          IdentifierInfo *&Name,
                                          SourceLocation NameLoc,
                                          const Token &NextToken,
                                          CorrectionCandidateCallback *CCC) {
DeclarationNameInfo NameInfo(Name, NameLoc);
ObjCMethodDecl *CurMethod = getCurMethodDecl();

assert(NextToken.isNot(tok::coloncolon) &&((void)0)
       "parse nested name specifiers before calling ClassifyName")((void)0);
if (getLangOpts().CPlusPlus && SS.isSet() &&
    isCurrentClassName(*Name, S, &SS)) {
  // Per [class.qual]p2, this names the constructors of SS, not the
  // injected-class-name. We don't have a classification for that.
  // There's not much point caching this result, since the parser
  // will reject it later.
  return NameClassification::Unknown();
}

LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
LookupParsedName(Result, S, &SS, !CurMethod);

if (SS.isInvalid())
  return NameClassification::Error();

// For unqualified lookup in a class template in MSVC mode, look into
// dependent base classes where the primary class template is known.
if (Result.empty() && SS.isEmpty() && getLangOpts().MSVCCompat) {
  if (ParsedType TypeInBase =
          recoverFromTypeInKnownDependentBase(*this, *Name, NameLoc))
    return TypeInBase;
}

// Perform lookup for Objective-C instance variables (including automatically
// synthesized instance variables), if we're in an Objective-C method.
// FIXME: This lookup really, really needs to be folded in to the normal
// unqualified lookup mechanism.
if (SS.isEmpty() && CurMethod && !isResultTypeOrTemplate(Result, NextToken)) {
  DeclResult Ivar = LookupIvarInObjCMethod(Result, S, Name);
  if (Ivar.isInvalid())
    return NameClassification::Error();
  if (Ivar.isUsable())
    return NameClassification::NonType(cast<NamedDecl>(Ivar.get()));

  // We defer builtin creation until after ivar lookup inside ObjC methods.
  if (Result.empty())
    LookupBuiltin(Result);
}

bool SecondTry = false;
bool IsFilteredTemplateName = false;

912Corrected:
switch (Result.getResultKind()) {
case LookupResult::NotFound:
  // If an unqualified-id is followed by a '(', then we have a function
  // call.
  if (SS.isEmpty() && NextToken.is(tok::l_paren)) {
    // In C++, this is an ADL-only call.
    // FIXME: Reference?
    if (getLangOpts().CPlusPlus)
      return NameClassification::UndeclaredNonType();

    // C90 6.3.2.2:
    //   If the expression that precedes the parenthesized argument list in a
    //   function call consists solely of an identifier, and if no
    //   declaration is visible for this identifier, the identifier is
    //   implicitly declared exactly as if, in the innermost block containing
    //   the function call, the declaration
    //
    //     extern int identifier ();
    //
    //   appeared.
    //
    // We also allow this in C99 as an extension.
    if (NamedDecl *D = ImplicitlyDefineFunction(NameLoc, *Name, S))
      return NameClassification::NonType(D);
  }

  if (getLangOpts().CPlusPlus20 && SS.isEmpty() && NextToken.is(tok::less)) {
    // In C++20 onwards, this could be an ADL-only call to a function
    // template, and we're required to assume that this is a template name.
    //
    // FIXME: Find a way to still do typo correction in this case.
    TemplateName Template =
        Context.getAssumedTemplateName(NameInfo.getName());
    return NameClassification::UndeclaredTemplate(Template);
  }

  // In C, we first see whether there is a tag type by the same name, in
  // which case it's likely that the user just forgot to write "enum",
  // "struct", or "union".
  if (!getLangOpts().CPlusPlus && !SecondTry &&
      isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
    break;
  }

  // Perform typo correction to determine if there is another name that is
  // close to this name.
  if (!SecondTry && CCC) {
    SecondTry = true;
    if (TypoCorrection Corrected =
            CorrectTypo(Result.getLookupNameInfo(), Result.getLookupKind(), S,
                        &SS, *CCC, CTK_ErrorRecovery)) {
      unsigned UnqualifiedDiag = diag::err_undeclared_var_use_suggest;
      unsigned QualifiedDiag = diag::err_no_member_suggest;

      NamedDecl *FirstDecl = Corrected.getFoundDecl();
      NamedDecl *UnderlyingFirstDecl = Corrected.getCorrectionDecl();
      if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
          UnderlyingFirstDecl && isa<TemplateDecl>(UnderlyingFirstDecl)) {
        UnqualifiedDiag = diag::err_no_template_suggest;
        QualifiedDiag = diag::err_no_member_template_suggest;
      } else if (UnderlyingFirstDecl &&
                 (isa<TypeDecl>(UnderlyingFirstDecl) ||
                  isa<ObjCInterfaceDecl>(UnderlyingFirstDecl) ||
                  isa<ObjCCompatibleAliasDecl>(UnderlyingFirstDecl))) {
        UnqualifiedDiag = diag::err_unknown_typename_suggest;
        QualifiedDiag = diag::err_unknown_nested_typename_suggest;
      }

      if (SS.isEmpty()) {
        diagnoseTypo(Corrected, PDiag(UnqualifiedDiag) << Name);
      } else {// FIXME: is this even reachable? Test it.
        std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
        bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
                                Name->getName().equals(CorrectedStr);
        diagnoseTypo(Corrected, PDiag(QualifiedDiag)
                                  << Name << computeDeclContext(SS, false)
                                  << DroppedSpecifier << SS.getRange());
      }

      // Update the name, so that the caller has the new name.
      Name = Corrected.getCorrectionAsIdentifierInfo();

      // Typo correction corrected to a keyword.
      if (Corrected.isKeyword())
        return Name;

      // Also update the LookupResult...
      // FIXME: This should probably go away at some point
      Result.clear();
      Result.setLookupName(Corrected.getCorrection());
      if (FirstDecl)
        Result.addDecl(FirstDecl);

      // If we found an Objective-C instance variable, let
      // LookupInObjCMethod build the appropriate expression to
      // reference the ivar.
      // FIXME: This is a gross hack.
      if (ObjCIvarDecl *Ivar = Result.getAsSingle<ObjCIvarDecl>()) {
        DeclResult R =
            LookupIvarInObjCMethod(Result, S, Ivar->getIdentifier());
        if (R.isInvalid())
          return NameClassification::Error();
        if (R.isUsable())
          return NameClassification::NonType(Ivar);
      }

      goto Corrected;
    }
  }

  // We failed to correct; just fall through and let the parser deal with it.
  Result.suppressDiagnostics();
  return NameClassification::Unknown();

case LookupResult::NotFoundInCurrentInstantiation: {
  // We performed name lookup into the current instantiation, and there were
  // dependent bases, so we treat this result the same way as any other
  // dependent nested-name-specifier.

  // C++ [temp.res]p2:
  //   A name used in a template declaration or definition and that is
  //   dependent on a template-parameter is assumed not to name a type
  //   unless the applicable name lookup finds a type name or the name is
  //   qualified by the keyword typename.
  //
  // FIXME: If the next token is '<', we might want to ask the parser to
  // perform some heroics to see if we actually have a
  // template-argument-list, which would indicate a missing 'template'
  // keyword here.
  return NameClassification::DependentNonType();
}

case LookupResult::Found:
case LookupResult::FoundOverloaded:
case LookupResult::FoundUnresolvedValue:
  break;

case LookupResult::Ambiguous:
  if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
      hasAnyAcceptableTemplateNames(Result, /*AllowFunctionTemplates=*/true,
                                    /*AllowDependent=*/false)) {
    // C++ [temp.local]p3:
    //   A lookup that finds an injected-class-name (10.2) can result in an
    //   ambiguity in certain cases (for example, if it is found in more than
    //   one base class). If all of the injected-class-names that are found
    //   refer to specializations of the same class template, and if the name
    //   is followed by a template-argument-list, the reference refers to the
    //   class template itself and not a specialization thereof, and is not
    //   ambiguous.
    //
    // This filtering can make an ambiguous result into an unambiguous one,
    // so try again after filtering out template names.
    FilterAcceptableTemplateNames(Result);
    if (!Result.isAmbiguous()) {
      IsFilteredTemplateName = true;
      break;
    }
  }

  // Diagnose the ambiguity and return an error.
  return NameClassification::Error();
}

if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
    (IsFilteredTemplateName ||
     hasAnyAcceptableTemplateNames(
         Result, /*AllowFunctionTemplates=*/true,
         /*AllowDependent=*/false,
         /*AllowNonTemplateFunctions*/ SS.isEmpty() &&
             getLangOpts().CPlusPlus20))) {
  // C++ [temp.names]p3:
  //   After name lookup (3.4) finds that a name is a template-name or that
  //   an operator-function-id or a literal- operator-id refers to a set of
  //   overloaded functions any member of which is a function template if
  //   this is followed by a <, the < is always taken as the delimiter of a
  //   template-argument-list and never as the less-than operator.
  // C++2a [temp.names]p2:
  //   A name is also considered to refer to a template if it is an
  //   unqualified-id followed by a < and name lookup finds either one
  //   or more functions or finds nothing.
  if (!IsFilteredTemplateName)
    FilterAcceptableTemplateNames(Result);

  bool IsFunctionTemplate;
  bool IsVarTemplate;
  TemplateName Template;
  if (Result.end() - Result.begin() > 1) {
    IsFunctionTemplate = true;
    Template = Context.getOverloadedTemplateName(Result.begin(),
                                                 Result.end());
  } else if (!Result.empty()) {
    auto *TD = cast<TemplateDecl>(getAsTemplateNameDecl(
        *Result.begin(), /*AllowFunctionTemplates=*/true,
        /*AllowDependent=*/false));
    IsFunctionTemplate = isa<FunctionTemplateDecl>(TD);
    IsVarTemplate = isa<VarTemplateDecl>(TD);

    if (SS.isNotEmpty())
      Template =
          Context.getQualifiedTemplateName(SS.getScopeRep(),
                                           /*TemplateKeyword=*/false, TD);
    else
      Template = TemplateName(TD);
  } else {
    // All results were non-template functions. This is a function template
    // name.
    IsFunctionTemplate = true;
    Template = Context.getAssumedTemplateName(NameInfo.getName());
  }

  if (IsFunctionTemplate) {
    // Function templates always go through overload resolution, at which
    // point we'll perform the various checks (e.g., accessibility) we need
    // to based on which function we selected.
    Result.suppressDiagnostics();

    return NameClassification::FunctionTemplate(Template);
  }

  return IsVarTemplate ? NameClassification::VarTemplate(Template)
                       : NameClassification::TypeTemplate(Template);
}

NamedDecl *FirstDecl = (*Result.begin())->getUnderlyingDecl();
if (TypeDecl *Type = dyn_cast<TypeDecl>(FirstDecl)) {
  DiagnoseUseOfDecl(Type, NameLoc);
  MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
  QualType T = Context.getTypeDeclType(Type);
  if (SS.isNotEmpty())
    return buildNestedType(*this, SS, T, NameLoc);
  return ParsedType::make(T);
}

ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(FirstDecl);
if (!Class) {
  // FIXME: It's unfortunate that we don't have a Type node for handling this.
  if (ObjCCompatibleAliasDecl *Alias =
          dyn_cast<ObjCCompatibleAliasDecl>(FirstDecl))
    Class = Alias->getClassInterface();
}

if (Class) {
  DiagnoseUseOfDecl(Class, NameLoc);

  if (NextToken.is(tok::period)) {
    // Interface. <something> is parsed as a property reference expression.
    // Just return "unknown" as a fall-through for now.
    Result.suppressDiagnostics();
    return NameClassification::Unknown();
  }

  QualType T = Context.getObjCInterfaceType(Class);
  return ParsedType::make(T);
}

if (isa<ConceptDecl>(FirstDecl))
  return NameClassification::Concept(
      TemplateName(cast<TemplateDecl>(FirstDecl)));

if (auto *EmptyD = dyn_cast<UnresolvedUsingIfExistsDecl>(FirstDecl)) {
  (void)DiagnoseUseOfDecl(EmptyD, NameLoc);
  return NameClassification::Error();
}

// We can have a type template here if we're classifying a template argument.
if (isa<TemplateDecl>(FirstDecl) && !isa<FunctionTemplateDecl>(FirstDecl) &&
    !isa<VarTemplateDecl>(FirstDecl))
  return NameClassification::TypeTemplate(
      TemplateName(cast<TemplateDecl>(FirstDecl)));

// Check for a tag type hidden by a non-type decl in a few cases where it
// seems likely a type is wanted instead of the non-type that was found.
bool NextIsOp = NextToken.isOneOf(tok::amp, tok::star);
if ((NextToken.is(tok::identifier) ||
     (NextIsOp &&
      FirstDecl->getUnderlyingDecl()->isFunctionOrFunctionTemplate())) &&
    isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
  TypeDecl *Type = Result.getAsSingle<TypeDecl>();
  DiagnoseUseOfDecl(Type, NameLoc);
  QualType T = Context.getTypeDeclType(Type);
  if (SS.isNotEmpty())
    return buildNestedType(*this, SS, T, NameLoc);
  return ParsedType::make(T);
}

// If we already know which single declaration is referenced, just annotate
// that declaration directly. Defer resolving even non-overloaded class
// member accesses, as we need to defer certain access checks until we know
// the context.
bool ADL = UseArgumentDependentLookup(SS, Result, NextToken.is(tok::l_paren));
if (Result.isSingleResult() && !ADL && !FirstDecl->isCXXClassMember())
  return NameClassification::NonType(Result.getRepresentativeDecl());

// Otherwise, this is an overload set that we will need to resolve later.
Result.suppressDiagnostics();
return NameClassification::OverloadSet(UnresolvedLookupExpr::Create(
    Context, Result.getNamingClass(), SS.getWithLocInContext(Context),
    Result.getLookupNameInfo(), ADL, Result.isOverloadedResult(),
    Result.begin(), Result.end()));
1212}

1214ExprResult
1215Sema::ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
                                           SourceLocation NameLoc) {
assert(getLangOpts().CPlusPlus && "ADL-only call in C?")((void)0);
CXXScopeSpec SS;
LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
return BuildDeclarationNameExpr(SS, Result, /*ADL=*/true);
1221}

1223ExprResult
1224Sema::ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
                                          IdentifierInfo *Name,
                                          SourceLocation NameLoc,
                                          bool IsAddressOfOperand) {
DeclarationNameInfo NameInfo(Name, NameLoc);
return ActOnDependentIdExpression(SS, /*TemplateKWLoc=*/SourceLocation(),
                                  NameInfo, IsAddressOfOperand,
                                  /*TemplateArgs=*/nullptr);
1232}

1234ExprResult Sema::ActOnNameClassifiedAsNonType(Scope *S, const CXXScopeSpec &SS,
                                            NamedDecl *Found,
                                            SourceLocation NameLoc,
                                            const Token &NextToken) {
if (getCurMethodDecl() && SS.isEmpty())
  if (auto *Ivar = dyn_cast<ObjCIvarDecl>(Found->getUnderlyingDecl()))
    return BuildIvarRefExpr(S, NameLoc, Ivar);

// Reconstruct the lookup result.
LookupResult Result(*this, Found->getDeclName(), NameLoc, LookupOrdinaryName);
Result.addDecl(Found);
Result.resolveKind();

bool ADL = UseArgumentDependentLookup(SS, Result, NextToken.is(tok::l_paren));
return BuildDeclarationNameExpr(SS, Result, ADL);
1249}

1251ExprResult Sema::ActOnNameClassifiedAsOverloadSet(Scope *S, Expr *E) {
// For an implicit class member access, transform the result into a member
// access expression if necessary.
auto *ULE = cast<UnresolvedLookupExpr>(E);
if ((*ULE->decls_begin())->isCXXClassMember()) {
  CXXScopeSpec SS;
  SS.Adopt(ULE->getQualifierLoc());

  // Reconstruct the lookup result.
  LookupResult Result(*this, ULE->getName(), ULE->getNameLoc(),
                      LookupOrdinaryName);
  Result.setNamingClass(ULE->getNamingClass());
  for (auto I = ULE->decls_begin(), E = ULE->decls_end(); I != E; ++I)
    Result.addDecl(*I, I.getAccess());
  Result.resolveKind();
  return BuildPossibleImplicitMemberExpr(SS, SourceLocation(), Result,
                                         nullptr, S);
}

// Otherwise, this is already in the form we needed, and no further checks
// are necessary.
return ULE;
1273}

1275Sema::TemplateNameKindForDiagnostics
1276Sema::getTemplateNameKindForDiagnostics(TemplateName Name) {
auto *TD = Name.getAsTemplateDecl();
if (!TD)
  return TemplateNameKindForDiagnostics::DependentTemplate;
if (isa<ClassTemplateDecl>(TD))
  return TemplateNameKindForDiagnostics::ClassTemplate;
if (isa<FunctionTemplateDecl>(TD))
  return TemplateNameKindForDiagnostics::FunctionTemplate;
if (isa<VarTemplateDecl>(TD))
  return TemplateNameKindForDiagnostics::VarTemplate;
if (isa<TypeAliasTemplateDecl>(TD))
  return TemplateNameKindForDiagnostics::AliasTemplate;
if (isa<TemplateTemplateParmDecl>(TD))
  return TemplateNameKindForDiagnostics::TemplateTemplateParam;
if (isa<ConceptDecl>(TD))
  return TemplateNameKindForDiagnostics::Concept;
return TemplateNameKindForDiagnostics::DependentTemplate;
1293}

1295void Sema::PushDeclContext(Scope *S, DeclContext *DC) {
assert(DC->getLexicalParent() == CurContext &&((void)0)
    "The next DeclContext should be lexically contained in the current one.")((void)0);
CurContext = DC;
S->setEntity(DC);
1300}

1302void Sema::PopDeclContext() {
assert(CurContext && "DeclContext imbalance!")((void)0);

CurContext = CurContext->getLexicalParent();
assert(CurContext && "Popped translation unit!")((void)0);
1307}

1309Sema::SkippedDefinitionContext Sema::ActOnTagStartSkippedDefinition(Scope *S,
                                                                  Decl *D) {
// Unlike PushDeclContext, the context to which we return is not necessarily
// the containing DC of TD, because the new context will be some pre-existing
// TagDecl definition instead of a fresh one.
auto Result = static_cast<SkippedDefinitionContext>(CurContext);
CurContext = cast<TagDecl>(D)->getDefinition();
assert(CurContext && "skipping definition of undefined tag")((void)0);
// Start lookups from the parent of the current context; we don't want to look
// into the pre-existing complete definition.
S->setEntity(CurContext->getLookupParent());
return Result;
1321}

1323void Sema::ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context) {
CurContext = static_cast<decltype(CurContext)>(Context);
1325}

1327/// EnterDeclaratorContext - Used when we must lookup names in the context
1328/// of a declarator's nested name specifier.
1329///
1330void Sema::EnterDeclaratorContext(Scope *S, DeclContext *DC) {
// C++0x [basic.lookup.unqual]p13:
//   A name used in the definition of a static data member of class
//   X (after the qualified-id of the static member) is looked up as
//   if the name was used in a member function of X.
// C++0x [basic.lookup.unqual]p14:
//   If a variable member of a namespace is defined outside of the
//   scope of its namespace then any name used in the definition of
//   the variable member (after the declarator-id) is looked up as
//   if the definition of the variable member occurred in its
//   namespace.
// Both of these imply that we should push a scope whose context
// is the semantic context of the declaration.  We can't use
// PushDeclContext here because that context is not necessarily
// lexically contained in the current context.  Fortunately,
// the containing scope should have the appropriate information.

assert(!S->getEntity() && "scope already has entity")((void)0);

1349#ifndef NDEBUG1
Scope *Ancestor = S->getParent();
while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
assert(Ancestor->getEntity() == CurContext && "ancestor context mismatch")((void)0);
1353#endif

CurContext = DC;
S->setEntity(DC);

if (S->getParent()->isTemplateParamScope()) {
  // Also set the corresponding entities for all immediately-enclosing
  // template parameter scopes.
  EnterTemplatedContext(S->getParent(), DC);
}
1363}

1365void Sema::ExitDeclaratorContext(Scope *S) {
assert(S->getEntity() == CurContext && "Context imbalance!")((void)0);

// Switch back to the lexical context.  The safety of this is
// enforced by an assert in EnterDeclaratorContext.
Scope *Ancestor = S->getParent();
while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
CurContext = Ancestor->getEntity();

// We don't need to do anything with the scope, which is going to
// disappear.
1376}

1378void Sema::EnterTemplatedContext(Scope *S, DeclContext *DC) {
assert(S->isTemplateParamScope() &&((void)0)
       "expected to be initializing a template parameter scope")((void)0);

// C++20 [temp.local]p7:
//   In the definition of a member of a class template that appears outside
//   of the class template definition, the name of a member of the class
//   template hides the name of a template-parameter of any enclosing class
//   templates (but not a template-parameter of the member if the member is a
//   class or function template).
// C++20 [temp.local]p9:
//   In the definition of a class template or in the definition of a member
//   of such a template that appears outside of the template definition, for
//   each non-dependent base class (13.8.2.1), if the name of the base class
//   or the name of a member of the base class is the same as the name of a
//   template-parameter, the base class name or member name hides the
//   template-parameter name (6.4.10).
//
// This means that a template parameter scope should be searched immediately
// after searching the DeclContext for which it is a template parameter
// scope. For example, for
//   template<typename T> template<typename U> template<typename V>
//     void N::A<T>::B<U>::f(...)
// we search V then B<U> (and base classes) then U then A<T> (and base
// classes) then T then N then ::.
unsigned ScopeDepth = getTemplateDepth(S);
for (; S && S->isTemplateParamScope(); S = S->getParent(), --ScopeDepth) {
  DeclContext *SearchDCAfterScope = DC;
  for (; DC; DC = DC->getLookupParent()) {
    if (const TemplateParameterList *TPL =
            cast<Decl>(DC)->getDescribedTemplateParams()) {
      unsigned DCDepth = TPL->getDepth() + 1;
      if (DCDepth > ScopeDepth)
        continue;
      if (ScopeDepth == DCDepth)
        SearchDCAfterScope = DC = DC->getLookupParent();
      break;
    }
  }
  S->setLookupEntity(SearchDCAfterScope);
}
1419}

1421void Sema::ActOnReenterFunctionContext(Scope* S, Decl *D) {
// We assume that the caller has already called
// ActOnReenterTemplateScope so getTemplatedDecl() works.
FunctionDecl *FD = D->getAsFunction();
if (!FD)
  return;

// Same implementation as PushDeclContext, but enters the context
// from the lexical parent, rather than the top-level class.
assert(CurContext == FD->getLexicalParent() &&((void)0)
  "The next DeclContext should be lexically contained in the current one.")((void)0);
CurContext = FD;
S->setEntity(CurContext);

for (unsigned P = 0, NumParams = FD->getNumParams(); P < NumParams; ++P) {
  ParmVarDecl *Param = FD->getParamDecl(P);
  // If the parameter has an identifier, then add it to the scope
  if (Param->getIdentifier()) {
    S->AddDecl(Param);
    IdResolver.AddDecl(Param);
  }
}
1443}

1445void Sema::ActOnExitFunctionContext() {
// Same implementation as PopDeclContext, but returns to the lexical parent,
// rather than the top-level class.
assert(CurContext && "DeclContext imbalance!")((void)0);
CurContext = CurContext->getLexicalParent();
assert(CurContext && "Popped translation unit!")((void)0);
1451}

1453/// Determine whether we allow overloading of the function
1454/// PrevDecl with another declaration.
1455///
1456/// This routine determines whether overloading is possible, not
1457/// whether some new function is actually an overload. It will return
1458/// true in C++ (where we can always provide overloads) or, as an
1459/// extension, in C when the previous function is already an
1460/// overloaded function declaration or has the "overloadable"
1461/// attribute.
1462static bool AllowOverloadingOfFunction(LookupResult &Previous,
                                     ASTContext &Context,
                                     const FunctionDecl *New) {
if (Context.getLangOpts().CPlusPlus)
  return true;

if (Previous.getResultKind() == LookupResult::FoundOverloaded)
  return true;

return Previous.getResultKind() == LookupResult::Found &&
       (Previous.getFoundDecl()->hasAttr<OverloadableAttr>() ||
        New->hasAttr<OverloadableAttr>());
1474}

1476/// Add this decl to the scope shadowed decl chains.
1477void Sema::PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext) {
// Move up the scope chain until we find the nearest enclosing
// non-transparent context. The declaration will be introduced into this
// scope.
while (S->getEntity() && S->getEntity()->isTransparentContext())
  S = S->getParent();

// Add scoped declarations into their context, so that they can be
// found later. Declarations without a context won't be inserted
// into any context.
if (AddToContext)
  CurContext->addDecl(D);

// Out-of-line definitions shouldn't be pushed into scope in C++, unless they
// are function-local declarations.
if (getLangOpts().CPlusPlus && D->isOutOfLine() && !S->getFnParent())
  return;

// Template instantiations should also not be pushed into scope.
if (isa<FunctionDecl>(D) &&
    cast<FunctionDecl>(D)->isFunctionTemplateSpecialization())
  return;

// If this replaces anything in the current scope,
IdentifierResolver::iterator I = IdResolver.begin(D->getDeclName()),
                             IEnd = IdResolver.end();
for (; I != IEnd; ++I) {
  if (S->isDeclScope(*I) && D->declarationReplaces(*I)) {
    S->RemoveDecl(*I);
    IdResolver.RemoveDecl(*I);

    // Should only need to replace one decl.
    break;
  }
}

S->AddDecl(D);

if (isa<LabelDecl>(D) && !cast<LabelDecl>(D)->isGnuLocal()) {
  // Implicitly-generated labels may end up getting generated in an order that
  // isn't strictly lexical, which breaks name lookup. Be careful to insert
  // the label at the appropriate place in the identifier chain.
  for (I = IdResolver.begin(D->getDeclName()); I != IEnd; ++I) {
    DeclContext *IDC = (*I)->getLexicalDeclContext()->getRedeclContext();
    if (IDC == CurContext) {
      if (!S->isDeclScope(*I))
        continue;
    } else if (IDC->Encloses(CurContext))
      break;
  }

  IdResolver.InsertDeclAfter(I, D);
} else {
  IdResolver.AddDecl(D);
}
warnOnReservedIdentifier(D);
1533}

1535bool Sema::isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S,
                       bool AllowInlineNamespace) {
return IdResolver.isDeclInScope(D, Ctx, S, AllowInlineNamespace);
1538}

1540Scope *Sema::getScopeForDeclContext(Scope *S, DeclContext *DC) {
DeclContext *TargetDC = DC->getPrimaryContext();
do {
  if (DeclContext *ScopeDC = S->getEntity())
    if (ScopeDC->getPrimaryContext() == TargetDC)
      return S;
} while ((S = S->getParent()));

return nullptr;
1549}

1551static bool isOutOfScopePreviousDeclaration(NamedDecl *,
                                          DeclContext*,
                                          ASTContext&);

1555/// Filters out lookup results that don't fall within the given scope
1556/// as determined by isDeclInScope.
1557void Sema::FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
                              bool ConsiderLinkage,
                              bool AllowInlineNamespace) {
LookupResult::Filter F = R.makeFilter();
while (F.hasNext()) {
  NamedDecl *D = F.next();

  if (isDeclInScope(D, Ctx, S, AllowInlineNamespace))
    continue;

  if (ConsiderLinkage && isOutOfScopePreviousDeclaration(D, Ctx, Context))
    continue;

  F.erase();
}

F.done();
1574}

1576/// We've determined that \p New is a redeclaration of \p Old. Check that they
1577/// have compatible owning modules.
1578bool Sema::CheckRedeclarationModuleOwnership(NamedDecl *New, NamedDecl *Old) {
// FIXME: The Modules TS is not clear about how friend declarations are
// to be treated. It's not meaningful to have different owning modules for
// linkage in redeclarations of the same entity, so for now allow the
// redeclaration and change the owning modules to match.
if (New->getFriendObjectKind() &&
    Old->getOwningModuleForLinkage() != New->getOwningModuleForLinkage()) {
  New->setLocalOwningModule(Old->getOwningModule());
  makeMergedDefinitionVisible(New);
  return false;
}

Module *NewM = New->getOwningModule();
Module *OldM = Old->getOwningModule();

if (NewM && NewM->Kind == Module::PrivateModuleFragment)
  NewM = NewM->Parent;
if (OldM && OldM->Kind == Module::PrivateModuleFragment)
  OldM = OldM->Parent;

if (NewM == OldM)
  return false;

bool NewIsModuleInterface = NewM && NewM->isModulePurview();
bool OldIsModuleInterface = OldM && OldM->isModulePurview();
if (NewIsModuleInterface || OldIsModuleInterface) {
  // C++ Modules TS [basic.def.odr] 6.2/6.7 [sic]:
  //   if a declaration of D [...] appears in the purview of a module, all
  //   other such declarations shall appear in the purview of the same module
  Diag(New->getLocation(), diag::err_mismatched_owning_module)
    << New
    << NewIsModuleInterface
    << (NewIsModuleInterface ? NewM->getFullModuleName() : "")
    << OldIsModuleInterface
    << (OldIsModuleInterface ? OldM->getFullModuleName() : "");
  Diag(Old->getLocation(), diag::note_previous_declaration);
  New->setInvalidDecl();
  return true;
}

return false;
1619}

1621static bool isUsingDecl(NamedDecl *D) {
return isa<UsingShadowDecl>(D) ||
       isa<UnresolvedUsingTypenameDecl>(D) ||
       isa<UnresolvedUsingValueDecl>(D);
1625}

1627/// Removes using shadow declarations from the lookup results.
1628static void RemoveUsingDecls(LookupResult &R) {
LookupResult::Filter F = R.makeFilter();
while (F.hasNext())
  if (isUsingDecl(F.next()))
    F.erase();

F.done();
1635}

1637/// Check for this common pattern:
1638/// @code
1639/// class S {
1640///   S(const S&); // DO NOT IMPLEMENT
1641///   void operator=(const S&); // DO NOT IMPLEMENT
1642/// };
1643/// @endcode
1644static bool IsDisallowedCopyOrAssign(const CXXMethodDecl *D) {
// FIXME: Should check for private access too but access is set after we get
// the decl here.
if (D->doesThisDeclarationHaveABody())
  return false;

if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
  return CD->isCopyConstructor();
return D->isCopyAssignmentOperator();
1653}

1655// We need this to handle
1656//
1657// typedef struct {
1658//   void *foo() { return 0; }
1659// } A;
1660//
1661// When we see foo we don't know if after the typedef we will get 'A' or '*A'
1662// for example. If 'A', foo will have external linkage. If we have '*A',
1663// foo will have no linkage. Since we can't know until we get to the end
1664// of the typedef, this function finds out if D might have non-external linkage.
1665// Callers should verify at the end of the TU if it D has external linkage or
1666// not.
1667bool Sema::mightHaveNonExternalLinkage(const DeclaratorDecl *D) {
const DeclContext *DC = D->getDeclContext();
while (!DC->isTranslationUnit()) {
  if (const RecordDecl *RD = dyn_cast<RecordDecl>(DC)){
    if (!RD->hasNameForLinkage())
      return true;
  }
  DC = DC->getParent();
}

return !D->isExternallyVisible();
1678}

1680// FIXME: This needs to be refactored; some other isInMainFile users want
1681// these semantics.
1682static bool isMainFileLoc(const Sema &S, SourceLocation Loc) {
if (S.TUKind != TU_Complete)
  return false;
return S.SourceMgr.isInMainFile(Loc);
1686}

1688bool Sema::ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const {
assert(D)((void)0);

if (D->isInvalidDecl() || D->isUsed() || D->hasAttr<UnusedAttr>())
  return false;

// Ignore all entities declared within templates, and out-of-line definitions
// of members of class templates.
if (D->getDeclContext()->isDependentContext() ||
    D->getLexicalDeclContext()->isDependentContext())
  return false;

if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
  if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
    return false;
  // A non-out-of-line declaration of a member specialization was implicitly
  // instantiated; it's the out-of-line declaration that we're interested in.
  if (FD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
      FD->getMemberSpecializationInfo() && !FD->isOutOfLine())
    return false;

  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
    if (MD->isVirtual() || IsDisallowedCopyOrAssign(MD))
      return false;
  } else {
    // 'static inline' functions are defined in headers; don't warn.
    if (FD->isInlined() && !isMainFileLoc(*this, FD->getLocation()))
      return false;
  }

  if (FD->doesThisDeclarationHaveABody() &&
      Context.DeclMustBeEmitted(FD))
    return false;
} else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
  // Constants and utility variables are defined in headers with internal
  // linkage; don't warn.  (Unlike functions, there isn't a convenient marker
  // like "inline".)
  if (!isMainFileLoc(*this, VD->getLocation()))
    return false;

  if (Context.DeclMustBeEmitted(VD))
    return false;

  if (VD->isStaticDataMember() &&
      VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
    return false;
  if (VD->isStaticDataMember() &&
      VD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
      VD->getMemberSpecializationInfo() && !VD->isOutOfLine())
    return false;

  if (VD->isInline() && !isMainFileLoc(*this, VD->getLocation()))
    return false;
} else {
  return false;
}

// Only warn for unused decls internal to the translation unit.
// FIXME: This seems like a bogus check; it suppresses -Wunused-function
// for inline functions defined in the main source file, for instance.
return mightHaveNonExternalLinkage(D);
1749}

1751void Sema::MarkUnusedFileScopedDecl(const DeclaratorDecl *D) {
if (!D)
  return;

if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
  const FunctionDecl *First = FD->getFirstDecl();
  if (FD != First && ShouldWarnIfUnusedFileScopedDecl(First))
    return; // First should already be in the vector.
}

if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
  const VarDecl *First = VD->getFirstDecl();
  if (VD != First && ShouldWarnIfUnusedFileScopedDecl(First))
    return; // First should already be in the vector.
}

if (ShouldWarnIfUnusedFileScopedDecl(D))
  UnusedFileScopedDecls.push_back(D);
1769}

1771static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
if (D->isInvalidDecl())
  return false;

if (auto *DD = dyn_cast<DecompositionDecl>(D)) {
  // For a decomposition declaration, warn if none of the bindings are
  // referenced, instead of if the variable itself is referenced (which
  // it is, by the bindings' expressions).
  for (auto *BD : DD->bindings())
    if (BD->isReferenced())
      return false;
} else if (!D->getDeclName()) {
  return false;
} else if (D->isReferenced() || D->isUsed()) {
  return false;
}

if (D->hasAttr<UnusedAttr>() || D->hasAttr<ObjCPreciseLifetimeAttr>())
  return false;

if (isa<LabelDecl>(D))
  return true;

// Except for labels, we only care about unused decls that are local to
// functions.
bool WithinFunction = D->getDeclContext()->isFunctionOrMethod();
if (const auto *R = dyn_cast<CXXRecordDecl>(D->getDeclContext()))
  // For dependent types, the diagnostic is deferred.
  WithinFunction =
      WithinFunction || (R->isLocalClass() && !R->isDependentType());
if (!WithinFunction)
  return false;

if (isa<TypedefNameDecl>(D))
  return true;

// White-list anything that isn't a local variable.
if (!isa<VarDecl>(D) || isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D))
  return false;

// Types of valid local variables should be complete, so this should succeed.
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {

  // White-list anything with an __attribute__((unused)) type.
  const auto *Ty = VD->getType().getTypePtr();

  // Only look at the outermost level of typedef.
  if (const TypedefType *TT = Ty->getAs<TypedefType>()) {
    if (TT->getDecl()->hasAttr<UnusedAttr>())
      return false;
  }

  // If we failed to complete the type for some reason, or if the type is
  // dependent, don't diagnose the variable.
  if (Ty->isIncompleteType() || Ty->isDependentType())
    return false;

  // Look at the element type to ensure that the warning behaviour is
  // consistent for both scalars and arrays.
  Ty = Ty->getBaseElementTypeUnsafe();

  if (const TagType *TT = Ty->getAs<TagType>()) {
    const TagDecl *Tag = TT->getDecl();
    if (Tag->hasAttr<UnusedAttr>())
      return false;

    if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Tag)) {
      if (!RD->hasTrivialDestructor() && !RD->hasAttr<WarnUnusedAttr>())
        return false;

      if (const Expr *Init = VD->getInit()) {
        if (const ExprWithCleanups *Cleanups =
                dyn_cast<ExprWithCleanups>(Init))
          Init = Cleanups->getSubExpr();
        const CXXConstructExpr *Construct =
          dyn_cast<CXXConstructExpr>(Init);
        if (Construct && !Construct->isElidable()) {
          CXXConstructorDecl *CD = Construct->getConstructor();
          if (!CD->isTrivial() && !RD->hasAttr<WarnUnusedAttr>() &&
              (VD->getInit()->isValueDependent() || !VD->evaluateValue()))
            return false;
        }

        // Suppress the warning if we don't know how this is constructed, and
        // it could possibly be non-trivial constructor.
        if (Init->isTypeDependent())
          for (const CXXConstructorDecl *Ctor : RD->ctors())
            if (!Ctor->isTrivial())
              return false;
      }
    }
  }

  // TODO: __attribute__((unused)) templates?
}

return true;
1868}

1870static void GenerateFixForUnusedDecl(const NamedDecl *D, ASTContext &Ctx,
                                   FixItHint &Hint) {
if (isa<LabelDecl>(D)) {
  SourceLocation AfterColon = Lexer::findLocationAfterToken(
      D->getEndLoc(), tok::colon, Ctx.getSourceManager(), Ctx.getLangOpts(),
      true);
  if (AfterColon.isInvalid())
    return;
  Hint = FixItHint::CreateRemoval(
      CharSourceRange::getCharRange(D->getBeginLoc(), AfterColon));
}
1881}

1883void Sema::DiagnoseUnusedNestedTypedefs(const RecordDecl *D) {
if (D->getTypeForDecl()->isDependentType())
  return;

for (auto *TmpD : D->decls()) {
  if (const auto *T = dyn_cast<TypedefNameDecl>(TmpD))
    DiagnoseUnusedDecl(T);
  else if(const auto *R = dyn_cast<RecordDecl>(TmpD))
    DiagnoseUnusedNestedTypedefs(R);
}
1893}

1895/// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
1896/// unless they are marked attr(unused).
1897void Sema::DiagnoseUnusedDecl(const NamedDecl *D) {
if (!ShouldDiagnoseUnusedDecl(D))
  return;

if (auto *TD = dyn_cast<TypedefNameDecl>(D)) {
  // typedefs can be referenced later on, so the diagnostics are emitted
  // at end-of-translation-unit.
  UnusedLocalTypedefNameCandidates.insert(TD);
  return;
}

FixItHint Hint;
GenerateFixForUnusedDecl(D, Context, Hint);

unsigned DiagID;
if (isa<VarDecl>(D) && cast<VarDecl>(D)->isExceptionVariable())
  DiagID = diag::warn_unused_exception_param;
else if (isa<LabelDecl>(D))
  DiagID = diag::warn_unused_label;
else
  DiagID = diag::warn_unused_variable;

Diag(D->getLocation(), DiagID) << D << Hint;
1920}

1922void Sema::DiagnoseUnusedButSetDecl(const VarDecl *VD) {
// If it's not referenced, it can't be set.
if (!VD->isReferenced() || !VD->getDeclName() || VD->hasAttr<UnusedAttr>())
  return;

const auto *Ty = VD->getType().getTypePtr()->getBaseElementTypeUnsafe();

if (Ty->isReferenceType() || Ty->isDependentType())
  return;

if (const TagType *TT = Ty->getAs<TagType>()) {
  const TagDecl *Tag = TT->getDecl();
  if (Tag->hasAttr<UnusedAttr>())
    return;
  // In C++, don't warn for record types that don't have WarnUnusedAttr, to
  // mimic gcc's behavior.
  if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Tag)) {
    if (!RD->hasAttr<WarnUnusedAttr>())
      return;
  }
}

auto iter = RefsMinusAssignments.find(VD);
if (iter == RefsMinusAssignments.end())
  return;

assert(iter->getSecond() >= 0 &&((void)0)
       "Found a negative number of references to a VarDecl")((void)0);
if (iter->getSecond() != 0)
  return;
unsigned DiagID = isa<ParmVarDecl>(VD) ? diag::warn_unused_but_set_parameter
                                       : diag::warn_unused_but_set_variable;
Diag(VD->getLocation(), DiagID) << VD;
1955}

1957static void CheckPoppedLabel(LabelDecl *L, Sema &S) {
// Verify that we have no forward references left.  If so, there was a goto
// or address of a label taken, but no definition of it.  Label fwd
// definitions are indicated with a null substmt which is also not a resolved
// MS inline assembly label name.
bool Diagnose = false;
if (L->isMSAsmLabel())
  Diagnose = !L->isResolvedMSAsmLabel();
else
  Diagnose = L->getStmt() == nullptr;
if (Diagnose)
  S.Diag(L->getLocation(), diag::err_undeclared_label_use) << L;
1969}

1971void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
S->mergeNRVOIntoParent();

if (S->decl_empty()) return;
assert((S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope)) &&((void)0)
       "Scope shouldn't contain decls!")((void)0);

for (auto *TmpD : S->decls()) {
  assert(TmpD && "This decl didn't get pushed??")((void)0);

  assert(isa<NamedDecl>(TmpD) && "Decl isn't NamedDecl?")((void)0);
  NamedDecl *D = cast<NamedDecl>(TmpD);

  // Diagnose unused variables in this scope.
  if (!S->hasUnrecoverableErrorOccurred()) {
    DiagnoseUnusedDecl(D);
    if (const auto *RD = dyn_cast<RecordDecl>(D))
      DiagnoseUnusedNestedTypedefs(RD);
    if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
      DiagnoseUnusedButSetDecl(VD);
      RefsMinusAssignments.erase(VD);
    }
  }

  if (!D->getDeclName()) continue;

  // If this was a forward reference to a label, verify it was defined.
  if (LabelDecl *LD = dyn_cast<LabelDecl>(D))
    CheckPoppedLabel(LD, *this);

  // Remove this name from our lexical scope, and warn on it if we haven't
  // already.
  IdResolver.RemoveDecl(D);
  auto ShadowI = ShadowingDecls.find(D);
  if (ShadowI != ShadowingDecls.end()) {
    if (const auto *FD = dyn_cast<FieldDecl>(ShadowI->second)) {
      Diag(D->getLocation(), diag::warn_ctor_parm_shadows_field)
          << D << FD << FD->getParent();
      Diag(FD->getLocation(), diag::note_previous_declaration);
    }
    ShadowingDecls.erase(ShadowI);
  }
}
2014}

2016/// Look for an Objective-C class in the translation unit.
2017///
2018/// \param Id The name of the Objective-C class we're looking for. If
2019/// typo-correction fixes this name, the Id will be updated
2020/// to the fixed name.
2021///
2022/// \param IdLoc The location of the name in the translation unit.
2023///
2024/// \param DoTypoCorrection If true, this routine will attempt typo correction
2025/// if there is no class with the given name.
2026///
2027/// \returns The declaration of the named Objective-C class, or NULL if the
2028/// class could not be found.
2029ObjCInterfaceDecl *Sema::getObjCInterfaceDecl(IdentifierInfo *&Id,
                                            SourceLocation IdLoc,
                                            bool DoTypoCorrection) {
// The third "scope" argument is 0 since we aren't enabling lazy built-in
// creation from this context.
NamedDecl *IDecl = LookupSingleName(TUScope, Id, IdLoc, LookupOrdinaryName);

if (!IDecl && DoTypoCorrection) {
  // Perform typo correction at the given location, but only if we
  // find an Objective-C class name.
  DeclFilterCCC<ObjCInterfaceDecl> CCC{};
  if (TypoCorrection C =
          CorrectTypo(DeclarationNameInfo(Id, IdLoc), LookupOrdinaryName,
                      TUScope, nullptr, CCC, CTK_ErrorRecovery)) {
    diagnoseTypo(C, PDiag(diag::err_undef_interface_suggest) << Id);
    IDecl = C.getCorrectionDeclAs<ObjCInterfaceDecl>();
    Id = IDecl->getIdentifier();
  }
}
ObjCInterfaceDecl *Def = dyn_cast_or_null<ObjCInterfaceDecl>(IDecl);
// This routine must always return a class definition, if any.
if (Def && Def->getDefinition())
    Def = Def->getDefinition();
return Def;
2053}

2055/// getNonFieldDeclScope - Retrieves the innermost scope, starting
2056/// from S, where a non-field would be declared. This routine copes
2057/// with the difference between C and C++ scoping rules in structs and
2058/// unions. For example, the following code is well-formed in C but
2059/// ill-formed in C++:
2060/// @code
2061/// struct S6 {
2062///   enum { BAR } e;
2063/// };
2064///
2065/// void test_S6() {
2066///   struct S6 a;
2067///   a.e = BAR;
2068/// }
2069/// @endcode
2070/// For the declaration of BAR, this routine will return a different
2071/// scope. The scope S will be the scope of the unnamed enumeration
2072/// within S6. In C++, this routine will return the scope associated
2073/// with S6, because the enumeration's scope is a transparent
2074/// context but structures can contain non-field names. In C, this
2075/// routine will return the translation unit scope, since the
2076/// enumeration's scope is a transparent context and structures cannot
2077/// contain non-field names.
2078Scope *Sema::getNonFieldDeclScope(Scope *S) {
while (((S->getFlags() & Scope::DeclScope) == 0) ||
       (S->getEntity() && S->getEntity()->isTransparentContext()) ||
       (S->isClassScope() && !getLangOpts().CPlusPlus))
  S = S->getParent();
return S;
2084}

2086static StringRef getHeaderName(Builtin::Context &BuiltinInfo, unsigned ID,
                             ASTContext::GetBuiltinTypeError Error) {
switch (Error) {
case ASTContext::GE_None:
  return "";
case ASTContext::GE_Missing_type:
  return BuiltinInfo.getHeaderName(ID);
case ASTContext::GE_Missing_stdio:
  return "stdio.h";
case ASTContext::GE_Missing_setjmp:
  return "setjmp.h";
case ASTContext::GE_Missing_ucontext:
  return "ucontext.h";
}
llvm_unreachable("unhandled error kind")__builtin_unreachable();
2101}

2103FunctionDecl *Sema::CreateBuiltin(IdentifierInfo *II, QualType Type,
                                unsigned ID, SourceLocation Loc) {
DeclContext *Parent = Context.getTranslationUnitDecl();

if (getLangOpts().CPlusPlus) {
  LinkageSpecDecl *CLinkageDecl = LinkageSpecDecl::Create(
      Context, Parent, Loc, Loc, LinkageSpecDecl::lang_c, false);
  CLinkageDecl->setImplicit();
  Parent->addDecl(CLinkageDecl);
  Parent = CLinkageDecl;
}

FunctionDecl *New = FunctionDecl::Create(Context, Parent, Loc, Loc, II, Type,
                                         /*TInfo=*/nullptr, SC_Extern, false,
                                         Type->isFunctionProtoType());
New->setImplicit();
New->addAttr(BuiltinAttr::CreateImplicit(Context, ID));

// Create Decl objects for each parameter, adding them to the
// FunctionDecl.
if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(Type)) {
  SmallVector<ParmVarDecl *, 16> Params;
  for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
    ParmVarDecl *parm = ParmVarDecl::Create(
        Context, New, SourceLocation(), SourceLocation(), nullptr,
        FT->getParamType(i), /*TInfo=*/nullptr, SC_None, nullptr);
    parm->setScopeInfo(0, i);
    Params.push_back(parm);
  }
  New->setParams(Params);
}

AddKnownFunctionAttributes(New);
return New;
2137}

2139/// LazilyCreateBuiltin - The specified Builtin-ID was first used at
2140/// file scope.  lazily create a decl for it. ForRedeclaration is true
2141/// if we're creating this built-in in anticipation of redeclaring the
2142/// built-in.
2143NamedDecl *Sema::LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
                                   Scope *S, bool ForRedeclaration,
                                   SourceLocation Loc) {
LookupNecessaryTypesForBuiltin(S, ID);

ASTContext::GetBuiltinTypeError Error;
QualType R = Context.GetBuiltinType(ID, Error);
if (Error) {
  if (!ForRedeclaration)
    return nullptr;

  // If we have a builtin without an associated type we should not emit a
  // warning when we were not able to find a type for it.
  if (Error == ASTContext::GE_Missing_type ||
      Context.BuiltinInfo.allowTypeMismatch(ID))
    return nullptr;

  // If we could not find a type for setjmp it is because the jmp_buf type was
  // not defined prior to the setjmp declaration.
  if (Error == ASTContext::GE_Missing_setjmp) {
    Diag(Loc, diag::warn_implicit_decl_no_jmp_buf)
        << Context.BuiltinInfo.getName(ID);
    return nullptr;
  }

  // Generally, we emit a warning that the declaration requires the
  // appropriate header.
  Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
      << getHeaderName(Context.BuiltinInfo, ID, Error)
      << Context.BuiltinInfo.getName(ID);
  return nullptr;
}

if (!ForRedeclaration &&
    (Context.BuiltinInfo.isPredefinedLibFunction(ID) ||
     Context.BuiltinInfo.isHeaderDependentFunction(ID))) {
  Diag(Loc, diag::ext_implicit_lib_function_decl)
      << Context.BuiltinInfo.getName(ID) << R;
  if (const char *Header = Context.BuiltinInfo.getHeaderName(ID))
    Diag(Loc, diag::note_include_header_or_declare)
        << Header << Context.BuiltinInfo.getName(ID);
}

if (R.isNull())
  return nullptr;

FunctionDecl *New = CreateBuiltin(II, R, ID, Loc);
RegisterLocallyScopedExternCDecl(New, S);

// TUScope is the translation-unit scope to insert this function into.
// FIXME: This is hideous. We need to teach PushOnScopeChains to
// relate Scopes to DeclContexts, and probably eliminate CurContext
// entirely, but we're not there yet.
DeclContext *SavedContext = CurContext;
CurContext = New->getDeclContext();
PushOnScopeChains(New, TUScope);
CurContext = SavedContext;
return New;
2201}

2203/// Typedef declarations don't have linkage, but they still denote the same
2204/// entity if their types are the same.
2205/// FIXME: This is notionally doing the same thing as ASTReaderDecl's
2206/// isSameEntity.
2207static void filterNonConflictingPreviousTypedefDecls(Sema &S,
                                                   TypedefNameDecl *Decl,
                                                   LookupResult &Previous) {
// This is only interesting when modules are enabled.
if (!S.getLangOpts().Modules && !S.getLangOpts().ModulesLocalVisibility)
  return;

// Empty sets are uninteresting.
if (Previous.empty())
  return;

LookupResult::Filter Filter = Previous.makeFilter();
while (Filter.hasNext()) {
  NamedDecl *Old = Filter.next();

  // Non-hidden declarations are never ignored.
  if (S.isVisible(Old))
    continue;

  // Declarations of the same entity are not ignored, even if they have
  // different linkages.
  if (auto *OldTD = dyn_cast<TypedefNameDecl>(Old)) {
    if (S.Context.hasSameType(OldTD->getUnderlyingType(),
                              Decl->getUnderlyingType()))
      continue;

    // If both declarations give a tag declaration a typedef name for linkage
    // purposes, then they declare the same entity.
    if (OldTD->getAnonDeclWithTypedefName(/*AnyRedecl*/true) &&
        Decl->getAnonDeclWithTypedefName())
      continue;
  }

  Filter.erase();
}

Filter.done();
2244}

2246bool Sema::isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New) {
QualType OldType;
if (TypedefNameDecl *OldTypedef = dyn_cast<TypedefNameDecl>(Old))
  OldType = OldTypedef->getUnderlyingType();
else
  OldType = Context.getTypeDeclType(Old);
QualType NewType = New->getUnderlyingType();

if (NewType->isVariablyModifiedType()) {
  // Must not redefine a typedef with a variably-modified type.
  int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
  Diag(New->getLocation(), diag::err_redefinition_variably_modified_typedef)
    << Kind << NewType;
  if (Old->getLocation().isValid())
    notePreviousDefinition(Old, New->getLocation());
  New->setInvalidDecl();
  return true;
}

if (OldType != NewType &&
    !OldType->isDependentType() &&
    !NewType->isDependentType() &&
    !Context.hasSameType(OldType, NewType)) {
  int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
  Diag(New->getLocation(), diag::err_redefinition_different_typedef)
    << Kind << NewType << OldType;
  if (Old->getLocation().isValid())
    notePreviousDefinition(Old, New->getLocation());
  New->setInvalidDecl();
  return true;
}
return false;
2278}

2280/// MergeTypedefNameDecl - We just parsed a typedef 'New' which has the
2281/// same name and scope as a previous declaration 'Old'.  Figure out
2282/// how to resolve this situation, merging decls or emitting
2283/// diagnostics as appropriate. If there was an error, set New to be invalid.
2284///
2285void Sema::MergeTypedefNameDecl(Scope *S, TypedefNameDecl *New,
                              LookupResult &OldDecls) {
// If the new decl is known invalid already, don't bother doing any
// merging checks.
if (New->isInvalidDecl()) return;

// Allow multiple definitions for ObjC built-in typedefs.
// FIXME: Verify the underlying types are equivalent!
if (getLangOpts().ObjC) {
  const IdentifierInfo *TypeID = New->getIdentifier();
  switch (TypeID->getLength()) {
  default: break;
  case 2:
    {
      if (!TypeID->isStr("id"))
        break;
      QualType T = New->getUnderlyingType();
      if (!T->isPointerType())
        break;
      if (!T->isVoidPointerType()) {
        QualType PT = T->castAs<PointerType>()->getPointeeType();
        if (!PT->isStructureType())
          break;
      }
      Context.setObjCIdRedefinitionType(T);
      // Install the built-in type for 'id', ignoring the current definition.
      New->setTypeForDecl(Context.getObjCIdType().getTypePtr());
      return;
    }
  case 5:
    if (!TypeID->isStr("Class"))
      break;
    Context.setObjCClassRedefinitionType(New->getUnderlyingType());
    // Install the built-in type for 'Class', ignoring the current definition.
    New->setTypeForDecl(Context.getObjCClassType().getTypePtr());
    return;
  case 3:
    if (!TypeID->isStr("SEL"))
      break;
    Context.setObjCSelRedefinitionType(New->getUnderlyingType());
    // Install the built-in type for 'SEL', ignoring the current definition.
    New->setTypeForDecl(Context.getObjCSelType().getTypePtr());
    return;
  }
  // Fall through - the typedef name was not a builtin type.
}

// Verify the old decl was also a type.
TypeDecl *Old = OldDecls.getAsSingle<TypeDecl>();
if (!Old) {
  Diag(New->getLocation(), diag::err_redefinition_different_kind)
    << New->getDeclName();

  NamedDecl *OldD = OldDecls.getRepresentativeDecl();
  if (OldD->getLocation().isValid())
    notePreviousDefinition(OldD, New->getLocation());

  return New->setInvalidDecl();
}

// If the old declaration is invalid, just give up here.
if (Old->isInvalidDecl())
  return New->setInvalidDecl();

if (auto *OldTD = dyn_cast<TypedefNameDecl>(Old)) {
  auto *OldTag = OldTD->getAnonDeclWithTypedefName(/*AnyRedecl*/true);
  auto *NewTag = New->getAnonDeclWithTypedefName();
  NamedDecl *Hidden = nullptr;
  if (OldTag && NewTag &&
      OldTag->getCanonicalDecl() != NewTag->getCanonicalDecl() &&
      !hasVisibleDefinition(OldTag, &Hidden)) {
    // There is a definition of this tag, but it is not visible. Use it
    // instead of our tag.
    New->setTypeForDecl(OldTD->getTypeForDecl());
    if (OldTD->isModed())
      New->setModedTypeSourceInfo(OldTD->getTypeSourceInfo(),
                                  OldTD->getUnderlyingType());
    else
      New->setTypeSourceInfo(OldTD->getTypeSourceInfo());

    // Make the old tag definition visible.
    makeMergedDefinitionVisible(Hidden);

    // If this was an unscoped enumeration, yank all of its enumerators
    // out of the scope.
    if (isa<EnumDecl>(NewTag)) {
      Scope *EnumScope = getNonFieldDeclScope(S);
      for (auto *D : NewTag->decls()) {
        auto *ED = cast<EnumConstantDecl>(D);
        assert(EnumScope->isDeclScope(ED))((void)0);
        EnumScope->RemoveDecl(ED);
        IdResolver.RemoveDecl(ED);
        ED->getLexicalDeclContext()->removeDecl(ED);
      }
    }
  }
}

// If the typedef types are not identical, reject them in all languages and
// with any extensions enabled.
if (isIncompatibleTypedef(Old, New))
  return;

// The types match.  Link up the redeclaration chain and merge attributes if
// the old declaration was a typedef.
if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Old)) {
  New->setPreviousDecl(Typedef);
  mergeDeclAttributes(New, Old);
}

if (getLangOpts().MicrosoftExt)
  return;

if (getLangOpts().CPlusPlus) {
  // C++ [dcl.typedef]p2:
  //   In a given non-class scope, a typedef specifier can be used to
  //   redefine the name of any type declared in that scope to refer
  //   to the type to which it already refers.
  if (!isa<CXXRecordDecl>(CurContext))
    return;

  // C++0x [dcl.typedef]p4:
  //   In a given class scope, a typedef specifier can be used to redefine
  //   any class-name declared in that scope that is not also a typedef-name
  //   to refer to the type to which it already refers.
  //
  // This wording came in via DR424, which was a correction to the
  // wording in DR56, which accidentally banned code like:
  //
  //   struct S {
  //     typedef struct A { } A;
  //   };
  //
  // in the C++03 standard. We implement the C++0x semantics, which
  // allow the above but disallow
  //
  //   struct S {
  //     typedef int I;
  //     typedef int I;
  //   };
  //
  // since that was the intent of DR56.
  if (!isa<TypedefNameDecl>(Old))
    return;

  Diag(New->getLocation(), diag::err_redefinition)
    << New->getDeclName();
  notePreviousDefinition(Old, New->getLocation());
  return New->setInvalidDecl();
}

// Modules always permit redefinition of typedefs, as does C11.
if (getLangOpts().Modules || getLangOpts().C11)
  return;

// If we have a redefinition of a typedef in C, emit a warning.  This warning
// is normally mapped to an error, but can be controlled with
// -Wtypedef-redefinition.  If either the original or the redefinition is
// in a system header, don't emit this for compatibility with GCC.
if (getDiagnostics().getSuppressSystemWarnings() &&
    // Some standard types are defined implicitly in Clang (e.g. OpenCL).
    (Old->isImplicit() ||
     Context.getSourceManager().isInSystemHeader(Old->getLocation()) ||
     Context.getSourceManager().isInSystemHeader(New->getLocation())))
  return;

Diag(New->getLocation(), diag::ext_redefinition_of_typedef)
  << New->getDeclName();
notePreviousDefinition(Old, New->getLocation());
2454}

2456/// DeclhasAttr - returns true if decl Declaration already has the target
2457/// attribute.
2458static bool DeclHasAttr(const Decl *D, const Attr *A) {
const OwnershipAttr *OA = dyn_cast<OwnershipAttr>(A);
const AnnotateAttr *Ann = dyn_cast<AnnotateAttr>(A);
for (const auto *i : D->attrs())
  if (i->getKind() == A->getKind()) {
    if (Ann) {
      if (Ann->getAnnotation() == cast<AnnotateAttr>(i)->getAnnotation())
        return true;
      continue;
    }
    // FIXME: Don't hardcode this check
    if (OA && isa<OwnershipAttr>(i))
      return OA->getOwnKind() == cast<OwnershipAttr>(i)->getOwnKind();
    return true;
  }

return false;
2475}

2477static bool isAttributeTargetADefinition(Decl *D) {
if (VarDecl *VD = dyn_cast<VarDecl>(D))
  return VD->isThisDeclarationADefinition();
if (TagDecl *TD = dyn_cast<TagDecl>(D))
  return TD->isCompleteDefinition() || TD->isBeingDefined();
return true;
2483}

2485/// Merge alignment attributes from \p Old to \p New, taking into account the
2486/// special semantics of C11's _Alignas specifier and C++11's alignas attribute.
2487///
2488/// \return \c true if any attributes were added to \p New.
2489static bool mergeAlignedAttrs(Sema &S, NamedDecl *New, Decl *Old) {
// Look for alignas attributes on Old, and pick out whichever attribute
// specifies the strictest alignment requirement.
AlignedAttr *OldAlignasAttr = nullptr;
AlignedAttr *OldStrictestAlignAttr = nullptr;
unsigned OldAlign = 0;
for (auto *I : Old->specific_attrs<AlignedAttr>()) {
  // FIXME: We have no way of representing inherited dependent alignments
  // in a case like:
  //   template<int A, int B> struct alignas(A) X;
  //   template<int A, int B> struct alignas(B) X {};
  // For now, we just ignore any alignas attributes which are not on the
  // definition in such a case.
  if (I->isAlignmentDependent())
    return false;

  if (I->isAlignas())
    OldAlignasAttr = I;

  unsigned Align = I->getAlignment(S.Context);
  if (Align > OldAlign) {
    OldAlign = Align;
    OldStrictestAlignAttr = I;
  }
}

// Look for alignas attributes on New.
AlignedAttr *NewAlignasAttr = nullptr;
unsigned NewAlign = 0;
for (auto *I : New->specific_attrs<AlignedAttr>()) {
  if (I->isAlignmentDependent())
    return false;

  if (I->isAlignas())
    NewAlignasAttr = I;

  unsigned Align = I->getAlignment(S.Context);
  if (Align > NewAlign)
    NewAlign = Align;
}

if (OldAlignasAttr && NewAlignasAttr && OldAlign != NewAlign) {
  // Both declarations have 'alignas' attributes. We require them to match.
  // C++11 [dcl.align]p6 and C11 6.7.5/7 both come close to saying this, but
  // fall short. (If two declarations both have alignas, they must both match
  // every definition, and so must match each other if there is a definition.)

  // If either declaration only contains 'alignas(0)' specifiers, then it
  // specifies the natural alignment for the type.
  if (OldAlign == 0 || NewAlign == 0) {
    QualType Ty;
    if (ValueDecl *VD = dyn_cast<ValueDecl>(New))
      Ty = VD->getType();
    else
      Ty = S.Context.getTagDeclType(cast<TagDecl>(New));

    if (OldAlign == 0)
      OldAlign = S.Context.getTypeAlign(Ty);
    if (NewAlign == 0)
      NewAlign = S.Context.getTypeAlign(Ty);
  }

  if (OldAlign != NewAlign) {
    S.Diag(NewAlignasAttr->getLocation(), diag::err_alignas_mismatch)
      << (unsigned)S.Context.toCharUnitsFromBits(OldAlign).getQuantity()
      << (unsigned)S.Context.toCharUnitsFromBits(NewAlign).getQuantity();
    S.Diag(OldAlignasAttr->getLocation(), diag::note_previous_declaration);
  }
}

if (OldAlignasAttr && !NewAlignasAttr && isAttributeTargetADefinition(New)) {
  // C++11 [dcl.align]p6:
  //   if any declaration of an entity has an alignment-specifier,
  //   every defining declaration of that entity shall specify an
  //   equivalent alignment.
  // C11 6.7.5/7:
  //   If the definition of an object does not have an alignment
  //   specifier, any other declaration of that object shall also
  //   have no alignment specifier.
  S.Diag(New->getLocation(), diag::err_alignas_missing_on_definition)
    << OldAlignasAttr;
  S.Diag(OldAlignasAttr->getLocation(), diag::note_alignas_on_declaration)
    << OldAlignasAttr;
}

bool AnyAdded = false;

// Ensure we have an attribute representing the strictest alignment.
if (OldAlign > NewAlign) {
  AlignedAttr *Clone = OldStrictestAlignAttr->clone(S.Context);
  Clone->setInherited(true);
  New->addAttr(Clone);
  AnyAdded = true;
}

// Ensure we have an alignas attribute if the old declaration had one.
if (OldAlignasAttr && !NewAlignasAttr &&
    !(AnyAdded && OldStrictestAlignAttr->isAlignas())) {
  AlignedAttr *Clone = OldAlignasAttr->clone(S.Context);
  Clone->setInherited(true);
  New->addAttr(Clone);
  AnyAdded = true;
}

return AnyAdded;
2594}

2596#define WANT_DECL_MERGE_LOGIC
2597#include "clang/Sema/AttrParsedAttrImpl.inc"
2598#undef WANT_DECL_MERGE_LOGIC

2600static bool mergeDeclAttribute(Sema &S, NamedDecl *D,
                             const InheritableAttr *Attr,
                             Sema::AvailabilityMergeKind AMK) {
// Diagnose any mutual exclusions between the attribute that we want to add
// and attributes that already exist on the declaration.
if (!DiagnoseMutualExclusions(S, D, Attr))
  return false;

// This function copies an attribute Attr from a previous declaration to the
// new declaration D if the new declaration doesn't itself have that attribute
// yet or if that attribute allows duplicates.
// If you're adding a new attribute that requires logic different from
// "use explicit attribute on decl if present, else use attribute from
// previous decl", for example if the attribute needs to be consistent
// between redeclarations, you need to call a custom merge function here.
InheritableAttr *NewAttr = nullptr;
if (const auto *AA = dyn_cast<AvailabilityAttr>(Attr))
  NewAttr = S.mergeAvailabilityAttr(
      D, *AA, AA->getPlatform(), AA->isImplicit(), AA->getIntroduced(),
      AA->getDeprecated(), AA->getObsoleted(), AA->getUnavailable(),
      AA->getMessage(), AA->getStrict(), AA->getReplacement(), AMK,
      AA->getPriority());
else if (const auto *VA = dyn_cast<VisibilityAttr>(Attr))
  NewAttr = S.mergeVisibilityAttr(D, *VA, VA->getVisibility());
else if (const auto *VA = dyn_cast<TypeVisibilityAttr>(Attr))
  NewAttr = S.mergeTypeVisibilityAttr(D, *VA, VA->getVisibility());
else if (const auto *ImportA = dyn_cast<DLLImportAttr>(Attr))
  NewAttr = S.mergeDLLImportAttr(D, *ImportA);
else if (const auto *ExportA = dyn_cast<DLLExportAttr>(Attr))
  NewAttr = S.mergeDLLExportAttr(D, *ExportA);
else if (const auto *FA = dyn_cast<FormatAttr>(Attr))
  NewAttr = S.mergeFormatAttr(D, *FA, FA->getType(), FA->getFormatIdx(),
                              FA->getFirstArg());
else if (const auto *SA = dyn_cast<SectionAttr>(Attr))
  NewAttr = S.mergeSectionAttr(D, *SA, SA->getName());
else if (const auto *CSA = dyn_cast<CodeSegAttr>(Attr))
  NewAttr = S.mergeCodeSegAttr(D, *CSA, CSA->getName());
else if (const auto *IA = dyn_cast<MSInheritanceAttr>(Attr))
  NewAttr = S.mergeMSInheritanceAttr(D, *IA, IA->getBestCase(),
                                     IA->getInheritanceModel());
else if (const auto *AA = dyn_cast<AlwaysInlineAttr>(Attr))
  NewAttr = S.mergeAlwaysInlineAttr(D, *AA,
                                    &S.Context.Idents.get(AA->getSpelling()));
else if (S.getLangOpts().CUDA && isa<FunctionDecl>(D) &&
         (isa<CUDAHostAttr>(Attr) || isa<CUDADeviceAttr>(Attr) ||
          isa<CUDAGlobalAttr>(Attr))) {
  // CUDA target attributes are part of function signature for
  // overloading purposes and must not be merged.
  return false;
} else if (const auto *MA = dyn_cast<MinSizeAttr>(Attr))
  NewAttr = S.mergeMinSizeAttr(D, *MA);
else if (const auto *SNA = dyn_cast<SwiftNameAttr>(Attr))
  NewAttr = S.mergeSwiftNameAttr(D, *SNA, SNA->getName());
else if (const auto *OA = dyn_cast<OptimizeNoneAttr>(Attr))
  NewAttr = S.mergeOptimizeNoneAttr(D, *OA);
else if (const auto *InternalLinkageA = dyn_cast<InternalLinkageAttr>(Attr))
  NewAttr = S.mergeInternalLinkageAttr(D, *InternalLinkageA);
else if (isa<AlignedAttr>(Attr))
  // AlignedAttrs are handled separately, because we need to handle all
  // such attributes on a declaration at the same time.
  NewAttr = nullptr;
else if ((isa<DeprecatedAttr>(Attr) || isa<UnavailableAttr>(Attr)) &&
         (AMK == Sema::AMK_Override ||
          AMK == Sema::AMK_ProtocolImplementation ||
          AMK == Sema::AMK_OptionalProtocolImplementation))
  NewAttr = nullptr;
else if (const auto *UA = dyn_cast<UuidAttr>(Attr))
  NewAttr = S.mergeUuidAttr(D, *UA, UA->getGuid(), UA->getGuidDecl());
else if (const auto *IMA = dyn_cast<WebAssemblyImportModuleAttr>(Attr))
  NewAttr = S.mergeImportModuleAttr(D, *IMA);
else if (const auto *INA = dyn_cast<WebAssemblyImportNameAttr>(Attr))
  NewAttr = S.mergeImportNameAttr(D, *INA);
else if (const auto *TCBA = dyn_cast<EnforceTCBAttr>(Attr))
  NewAttr = S.mergeEnforceTCBAttr(D, *TCBA);
else if (const auto *TCBLA = dyn_cast<EnforceTCBLeafAttr>(Attr))
  NewAttr = S.mergeEnforceTCBLeafAttr(D, *TCBLA);
else if (Attr->shouldInheritEvenIfAlreadyPresent() || !DeclHasAttr(D, Attr))
  NewAttr = cast<InheritableAttr>(Attr->clone(S.Context));

if (NewAttr) {
  NewAttr->setInherited(true);
  D->addAttr(NewAttr);
  if (isa<MSInheritanceAttr>(NewAttr))
    S.Consumer.AssignInheritanceModel(cast<CXXRecordDecl>(D));
  return true;
}

return false;
2688}

2690static const NamedDecl *getDefinition(const Decl *D) {
if (const TagDecl *TD = dyn_cast<TagDecl>(D))
  return TD->getDefinition();
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
  const VarDecl *Def = VD->getDefinition();
  if (Def)
    return Def;
  return VD->getActingDefinition();
}
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
  const FunctionDecl *Def = nullptr;
  if (FD->isDefined(Def, true))
    return Def;
}
return nullptr;
2705}

2707static bool hasAttribute(const Decl *D, attr::Kind Kind) {
for (const auto *Attribute : D->attrs())
  if (Attribute->getKind() == Kind)
    return true;
return false;
2712}

2714/// checkNewAttributesAfterDef - If we already have a definition, check that
2715/// there are no new attributes in this declaration.
2716static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
if (!New->hasAttrs())
  return;

const NamedDecl *Def = getDefinition(Old);
if (!Def || Def == New)
  return;

AttrVec &NewAttributes = New->getAttrs();
for (unsigned I = 0, E = NewAttributes.size(); I != E;) {
  const Attr *NewAttribute = NewAttributes[I];

  if (isa<AliasAttr>(NewAttribute) || isa<IFuncAttr>(NewAttribute)) {
    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(New)) {
      Sema::SkipBodyInfo SkipBody;
      S.CheckForFunctionRedefinition(FD, cast<FunctionDecl>(Def), &SkipBody);

      // If we're skipping this definition, drop the "alias" attribute.
      if (SkipBody.ShouldSkip) {
        NewAttributes.erase(NewAttributes.begin() + I);
        --E;
        continue;
      }
    } else {
      VarDecl *VD = cast<VarDecl>(New);
      unsigned Diag = cast<VarDecl>(Def)->isThisDeclarationADefinition() ==
                              VarDecl::TentativeDefinition
                          ? diag::err_alias_after_tentative
                          : diag::err_redefinition;
      S.Diag(VD->getLocation(), Diag) << VD->getDeclName();
      if (Diag == diag::err_redefinition)
        S.notePreviousDefinition(Def, VD->getLocation());
      else
        S.Diag(Def->getLocation(), diag::note_previous_definition);
      VD->setInvalidDecl();
    }
    ++I;
    continue;
  }

  if (const VarDecl *VD = dyn_cast<VarDecl>(Def)) {
    // Tentative definitions are only interesting for the alias check above.
    if (VD->isThisDeclarationADefinition() != VarDecl::Definition) {
      ++I;
      continue;
    }
  }

  if (hasAttribute(Def, NewAttribute->getKind())) {
    ++I;
    continue; // regular attr merging will take care of validating this.
  }

  if (isa<C11NoReturnAttr>(NewAttribute)) {
    // C's _Noreturn is allowed to be added to a function after it is defined.
    ++I;
    continue;
  } else if (isa<UuidAttr>(NewAttribute)) {
    // msvc will allow a subsequent definition to add an uuid to a class
    ++I;
    continue;
  } else if (const AlignedAttr *AA = dyn_cast<AlignedAttr>(NewAttribute)) {
    if (AA->isAlignas()) {
      // C++11 [dcl.align]p6:
      //   if any declaration of an entity has an alignment-specifier,
      //   every defining declaration of that entity shall specify an
      //   equivalent alignment.
      // C11 6.7.5/7:
      //   If the definition of an object does not have an alignment
      //   specifier, any other declaration of that object shall also
      //   have no alignment specifier.
      S.Diag(Def->getLocation(), diag::err_alignas_missing_on_definition)
        << AA;
      S.Diag(NewAttribute->getLocation(), diag::note_alignas_on_declaration)
        << AA;
      NewAttributes.erase(NewAttributes.begin() + I);
      --E;
      continue;
    }
  } else if (isa<LoaderUninitializedAttr>(NewAttribute)) {
    // If there is a C definition followed by a redeclaration with this
    // attribute then there are two different definitions. In C++, prefer the
    // standard diagnostics.
    if (!S.getLangOpts().CPlusPlus) {
      S.Diag(NewAttribute->getLocation(),
             diag::err_loader_uninitialized_redeclaration);
      S.Diag(Def->getLocation(), diag::note_previous_definition);
      NewAttributes.erase(NewAttributes.begin() + I);
      --E;
      continue;
    }
  } else if (isa<SelectAnyAttr>(NewAttribute) &&
             cast<VarDecl>(New)->isInline() &&
             !cast<VarDecl>(New)->isInlineSpecified()) {
    // Don't warn about applying selectany to implicitly inline variables.
    // Older compilers and language modes would require the use of selectany
    // to make such variables inline, and it would have no effect if we
    // honored it.
    ++I;
    continue;
  } else if (isa<OMPDeclareVariantAttr>(NewAttribute)) {
    // We allow to add OMP[Begin]DeclareVariantAttr to be added to
    // declarations after defintions.
    ++I;
    continue;
  }

  S.Diag(NewAttribute->getLocation(),
         diag::warn_attribute_precede_definition);
  S.Diag(Def->getLocation(), diag::note_previous_definition);
  NewAttributes.erase(NewAttributes.begin() + I);
  --E;
}
2829}

2831static void diagnoseMissingConstinit(Sema &S, const VarDecl *InitDecl,
                                   const ConstInitAttr *CIAttr,
                                   bool AttrBeforeInit) {
SourceLocation InsertLoc = InitDecl->getInnerLocStart();

// Figure out a good way to write this specifier on the old declaration.
// FIXME: We should just use the spelling of CIAttr, but we don't preserve
// enough of the attribute list spelling information to extract that without
// heroics.
std::string SuitableSpelling;
if (S.getLangOpts().CPlusPlus20)
  SuitableSpelling = std::string(
      S.PP.getLastMacroWithSpelling(InsertLoc, {tok::kw_constinit}));
if (SuitableSpelling.empty() && S.getLangOpts().CPlusPlus11)
  SuitableSpelling = std::string(S.PP.getLastMacroWithSpelling(
      InsertLoc, {tok::l_square, tok::l_square,
                  S.PP.getIdentifierInfo("clang"), tok::coloncolon,
                  S.PP.getIdentifierInfo("require_constant_initialization"),
                  tok::r_square, tok::r_square}));
if (SuitableSpelling.empty())
  SuitableSpelling = std::string(S.PP.getLastMacroWithSpelling(
      InsertLoc, {tok::kw___attribute, tok::l_paren, tok::r_paren,
                  S.PP.getIdentifierInfo("require_constant_initialization"),
                  tok::r_paren, tok::r_paren}));
if (SuitableSpelling.empty() && S.getLangOpts().CPlusPlus20)
  SuitableSpelling = "constinit";
if (SuitableSpelling.empty() && S.getLangOpts().CPlusPlus11)
  SuitableSpelling = "[[clang::require_constant_initialization]]";
if (SuitableSpelling.empty())
  SuitableSpelling = "__attribute__((require_constant_initialization))";
SuitableSpelling += " ";

if (AttrBeforeInit) {
  // extern constinit int a;
  // int a = 0; // error (missing 'constinit'), accepted as extension
  assert(CIAttr->isConstinit() && "should not diagnose this for attribute")((void)0);
  S.Diag(InitDecl->getLocation(), diag::ext_constinit_missing)
      << InitDecl << FixItHint::CreateInsertion(InsertLoc, SuitableSpelling);
  S.Diag(CIAttr->getLocation(), diag::note_constinit_specified_here);
} else {
  // int a = 0;
  // constinit extern int a; // error (missing 'constinit')
  S.Diag(CIAttr->getLocation(),
         CIAttr->isConstinit() ? diag::err_constinit_added_too_late
                               : diag::warn_require_const_init_added_too_late)
      << FixItHint::CreateRemoval(SourceRange(CIAttr->getLocation()));
  S.Diag(InitDecl->getLocation(), diag::note_constinit_missing_here)
      << CIAttr->isConstinit()
      << FixItHint::CreateInsertion(InsertLoc, SuitableSpelling);
}
2881}

2883/// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
2884void Sema::mergeDeclAttributes(NamedDecl *New, Decl *Old,
                             AvailabilityMergeKind AMK) {
if (UsedAttr *OldAttr = Old->getMostRecentDecl()->getAttr<UsedAttr>()) {
  UsedAttr *NewAttr = OldAttr->clone(Context);
  NewAttr->setInherited(true);
  New->addAttr(NewAttr);
}
if (RetainAttr *OldAttr = Old->getMostRecentDecl()->getAttr<RetainAttr>()) {
  RetainAttr *NewAttr = OldAttr->clone(Context);
  NewAttr->setInherited(true);
  New->addAttr(NewAttr);
}

if (!Old->hasAttrs() && !New->hasAttrs())
  return;

// [dcl.constinit]p1:
//   If the [constinit] specifier is applied to any declaration of a
//   variable, it shall be applied to the initializing declaration.
const auto *OldConstInit = Old->getAttr<ConstInitAttr>();
const auto *NewConstInit = New->getAttr<ConstInitAttr>();
if (bool(OldConstInit) != bool(NewConstInit)) {
  const auto *OldVD = cast<VarDecl>(Old);
  auto *NewVD = cast<VarDecl>(New);

  // Find the initializing declaration. Note that we might not have linked
  // the new declaration into the redeclaration chain yet.
  const VarDecl *InitDecl = OldVD->getInitializingDeclaration();
  if (!InitDecl &&
      (NewVD->hasInit() || NewVD->isThisDeclarationADefinition()))
    InitDecl = NewVD;

  if (InitDecl == NewVD) {
    // This is the initializing declaration. If it would inherit 'constinit',
    // that's ill-formed. (Note that we do not apply this to the attribute
    // form).
    if (OldConstInit && OldConstInit->isConstinit())
      diagnoseMissingConstinit(*this, NewVD, OldConstInit,
                               /*AttrBeforeInit=*/true);
  } else if (NewConstInit) {
    // This is the first time we've been told that this declaration should
    // have a constant initializer. If we already saw the initializing
    // declaration, this is too late.
    if (InitDecl && InitDecl != NewVD) {
      diagnoseMissingConstinit(*this, InitDecl, NewConstInit,
                               /*AttrBeforeInit=*/false);
      NewVD->dropAttr<ConstInitAttr>();
    }
  }
}

// Attributes declared post-definition are currently ignored.
checkNewAttributesAfterDef(*this, New, Old);

if (AsmLabelAttr *NewA = New->getAttr<AsmLabelAttr>()) {
  if (AsmLabelAttr *OldA = Old->getAttr<AsmLabelAttr>()) {
    if (!OldA->isEquivalent(NewA)) {
      // This redeclaration changes __asm__ label.
      Diag(New->getLocation(), diag::err_different_asm_label);
      Diag(OldA->getLocation(), diag::note_previous_declaration);
    }
  } else if (Old->isUsed()) {
    // This redeclaration adds an __asm__ label to a declaration that has
    // already been ODR-used.
    Diag(New->getLocation(), diag::err_late_asm_label_name)
      << isa<FunctionDecl>(Old) << New->getAttr<AsmLabelAttr>()->getRange();
  }
}

// Re-declaration cannot add abi_tag's.
if (const auto *NewAbiTagAttr = New->getAttr<AbiTagAttr>()) {
  if (const auto *OldAbiTagAttr = Old->getAttr<AbiTagAttr>()) {
    for (const auto &NewTag : NewAbiTagAttr->tags()) {
      if (std::find(OldAbiTagAttr->tags_begin(), OldAbiTagAttr->tags_end(),
                    NewTag) == OldAbiTagAttr->tags_end()) {
        Diag(NewAbiTagAttr->getLocation(),
             diag::err_new_abi_tag_on_redeclaration)
            << NewTag;
        Diag(OldAbiTagAttr->getLocation(), diag::note_previous_declaration);
      }
    }
  } else {
    Diag(NewAbiTagAttr->getLocation(), diag::err_abi_tag_on_redeclaration);
    Diag(Old->getLocation(), diag::note_previous_declaration);
  }
}

// This redeclaration adds a section attribute.
if (New->hasAttr<SectionAttr>() && !Old->hasAttr<SectionAttr>()) {
  if (auto *VD = dyn_cast<VarDecl>(New)) {
    if (VD->isThisDeclarationADefinition() == VarDecl::DeclarationOnly) {
      Diag(New->getLocation(), diag::warn_attribute_section_on_redeclaration);
      Diag(Old->getLocation(), diag::note_previous_declaration);
    }
  }
}

// Redeclaration adds code-seg attribute.
const auto *NewCSA = New->getAttr<CodeSegAttr>();
if (NewCSA && !Old->hasAttr<CodeSegAttr>() &&
    !NewCSA->isImplicit() && isa<CXXMethodDecl>(New)) {
  Diag(New->getLocation(), diag::warn_mismatched_section)
       << 0 /*codeseg*/;
  Diag(Old->getLocation(), diag::note_previous_declaration);
}

if (!Old->hasAttrs())
  return;

bool foundAny = New->hasAttrs();

// Ensure that any moving of objects within the allocated map is done before
// we process them.
if (!foundAny) New->setAttrs(AttrVec());

for (auto *I : Old->specific_attrs<InheritableAttr>()) {
  // Ignore deprecated/unavailable/availability attributes if requested.
  AvailabilityMergeKind LocalAMK = AMK_None;
  if (isa<DeprecatedAttr>(I) ||
      isa<UnavailableAttr>(I) ||
      isa<AvailabilityAttr>(I)) {
    switch (AMK) {
    case AMK_None:
      continue;

    case AMK_Redeclaration:
    case AMK_Override:
    case AMK_ProtocolImplementation:
    case AMK_OptionalProtocolImplementation:
      LocalAMK = AMK;
      break;
    }
  }

  // Already handled.
  if (isa<UsedAttr>(I) || isa<RetainAttr>(I))
    continue;

  if (mergeDeclAttribute(*this, New, I, LocalAMK))
    foundAny = true;
}

if (mergeAlignedAttrs(*this, New, Old))
  foundAny = true;

if (!foundAny) New->dropAttrs();
3030}

3032/// mergeParamDeclAttributes - Copy attributes from the old parameter
3033/// to the new one.
3034static void mergeParamDeclAttributes(ParmVarDecl *newDecl,
                                   const ParmVarDecl *oldDecl,
                                   Sema &S) {
// C++11 [dcl.attr.depend]p2:
//   The first declaration of a function shall specify the
//   carries_dependency attribute for its declarator-id if any declaration
//   of the function specifies the carries_dependency attribute.
const CarriesDependencyAttr *CDA = newDecl->getAttr<CarriesDependencyAttr>();
if (CDA && !oldDecl->hasAttr<CarriesDependencyAttr>()) {
  S.Diag(CDA->getLocation(),
         diag::err_carries_dependency_missing_on_first_decl) << 1/*Param*/;
  // Find the first declaration of the parameter.
  // FIXME: Should we build redeclaration chains for function parameters?
  const FunctionDecl *FirstFD =
    cast<FunctionDecl>(oldDecl->getDeclContext())->getFirstDecl();
  const ParmVarDecl *FirstVD =
    FirstFD->getParamDecl(oldDecl->getFunctionScopeIndex());
  S.Diag(FirstVD->getLocation(),
         diag::note_carries_dependency_missing_first_decl) << 1/*Param*/;
}

if (!oldDecl->hasAttrs())
  return;

bool foundAny = newDecl->hasAttrs();

// Ensure that any moving of objects within the allocated map is
// done before we process them.
if (!foundAny) newDecl->setAttrs(AttrVec());

for (const auto *I : oldDecl->specific_attrs<InheritableParamAttr>()) {
  if (!DeclHasAttr(newDecl, I)) {
    InheritableAttr *newAttr =
      cast<InheritableParamAttr>(I->clone(S.Context));
    newAttr->setInherited(true);
    newDecl->addAttr(newAttr);
    foundAny = true;
  }
}

if (!foundAny) newDecl->dropAttrs();
3075}

3077static void mergeParamDeclTypes(ParmVarDecl *NewParam,
                              const ParmVarDecl *OldParam,
                              Sema &S) {
if (auto Oldnullability = OldParam->getType()->getNullability(S.Context)) {
  if (auto Newnullability = NewParam->getType()->getNullability(S.Context)) {
    if (*Oldnullability != *Newnullability) {
      S.Diag(NewParam->getLocation(), diag::warn_mismatched_nullability_attr)
        << DiagNullabilityKind(
             *Newnullability,
             ((NewParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability)
              != 0))
        << DiagNullabilityKind(
             *Oldnullability,
             ((OldParam->getObjCDeclQualifier() & Decl::OBJC_TQ_CSNullability)
              != 0));
      S.Diag(OldParam->getLocation(), diag::note_previous_declaration);
    }
  } else {
    QualType NewT = NewParam->getType();
    NewT = S.Context.getAttributedType(
                       AttributedType::getNullabilityAttrKind(*Oldnullability),
                       NewT, NewT);
    NewParam->setType(NewT);
  }
}
3102}

3104namespace {

3106/// Used in MergeFunctionDecl to keep track of function parameters in
3107/// C.
3108struct GNUCompatibleParamWarning {
ParmVarDecl *OldParm;
ParmVarDecl *NewParm;
QualType PromotedType;
3112};

3114} // end anonymous namespace

3116// Determine whether the previous declaration was a definition, implicit
3117// declaration, or a declaration.
3118template <typename T>
3119static std::pair<diag::kind, SourceLocation>
3120getNoteDiagForInvalidRedeclaration(const T *Old, const T *New) {
diag::kind PrevDiag;
SourceLocation OldLocation = Old->getLocation();
if (Old->isThisDeclarationADefinition())
  PrevDiag = diag::note_previous_definition;
else if (Old->isImplicit()) {
  PrevDiag = diag::note_previous_implicit_declaration;
  if (OldLocation.isInvalid())
    OldLocation = New->getLocation();
} else
  PrevDiag = diag::note_previous_declaration;
return std::make_pair(PrevDiag, OldLocation);
3132}

3134/// canRedefineFunction - checks if a function can be redefined. Currently,
3135/// only extern inline functions can be redefined, and even then only in
3136/// GNU89 mode.
3137static bool canRedefineFunction(const FunctionDecl *FD,
                              const LangOptions& LangOpts) {
return ((FD->hasAttr<GNUInlineAttr>() || LangOpts.GNUInline) &&
        !LangOpts.CPlusPlus &&
        FD->isInlineSpecified() &&
        FD->getStorageClass() == SC_Extern);
3143}

3145const AttributedType *Sema::getCallingConvAttributedType(QualType T) const {
const AttributedType *AT = T->getAs<AttributedType>();
while (AT && !AT->isCallingConv())
  AT = AT->getModifiedType()->getAs<AttributedType>();
return AT;
3150}

3152template <typename T>
3153static bool haveIncompatibleLanguageLinkages(const T *Old, const T *New) {
const DeclContext *DC = Old->getDeclContext();
if (DC->isRecord())
  return false;

LanguageLinkage OldLinkage = Old->getLanguageLinkage();
if (OldLinkage == CXXLanguageLinkage && New->isInExternCContext())
  return true;
if (OldLinkage == CLanguageLinkage && New->isInExternCXXContext())
  return true;
return false;
3164}

3166template<typename T> static bool isExternC(T *D) { return D->isExternC(); }
3167static bool isExternC(VarTemplateDecl *) { return false; }
3168static bool isExternC(FunctionTemplateDecl *) { return false; }

3170/// Check whether a redeclaration of an entity introduced by a
3171/// using-declaration is valid, given that we know it's not an overload
3172/// (nor a hidden tag declaration).
3173template<typename ExpectedDecl>
3174static bool checkUsingShadowRedecl(Sema &S, UsingShadowDecl *OldS,
                                 ExpectedDecl *New) {
// C++11 [basic.scope.declarative]p4:
//   Given a set of declarations in a single declarative region, each of
//   which specifies the same unqualified name,
//   -- they shall all refer to the same entity, or all refer to functions
//      and function templates; or
//   -- exactly one declaration shall declare a class name or enumeration
//      name that is not a typedef name and the other declarations shall all
//      refer to the same variable or enumerator, or all refer to functions
//      and function templates; in this case the class name or enumeration
//      name is hidden (3.3.10).

// C++11 [namespace.udecl]p14:
//   If a function declaration in namespace scope or block scope has the
//   same name and the same parameter-type-list as a function introduced
//   by a using-declaration, and the declarations do not declare the same
//   function, the program is ill-formed.

auto *Old = dyn_cast<ExpectedDecl>(OldS->getTargetDecl());
if (Old &&
    !Old->getDeclContext()->getRedeclContext()->Equals(
        New->getDeclContext()->getRedeclContext()) &&
    !(isExternC(Old) && isExternC(New)))
  Old = nullptr;

if (!Old) {
  S.Diag(New->getLocation(), diag::err_using_decl_conflict_reverse);
  S.Diag(OldS->getTargetDecl()->getLocation(), diag::note_using_decl_target);
  S.Diag(OldS->getIntroducer()->getLocation(), diag::note_using_decl) << 0;
  return true;
}
return false;
3207}

3209static bool hasIdenticalPassObjectSizeAttrs(const FunctionDecl *A,
                                          const FunctionDecl *B) {
assert(A->getNumParams() == B->getNumParams())((void)0);

auto AttrEq = [](const ParmVarDecl *A, const ParmVarDecl *B) {
  const auto *AttrA = A->getAttr<PassObjectSizeAttr>();
  const auto *AttrB = B->getAttr<PassObjectSizeAttr>();
  if (AttrA == AttrB)
    return true;
  return AttrA && AttrB && AttrA->getType() == AttrB->getType() &&
         AttrA->isDynamic() == AttrB->isDynamic();
};

return std::equal(A->param_begin(), A->param_end(), B->param_begin(), AttrEq);
3223}

3225/// If necessary, adjust the semantic declaration context for a qualified
3226/// declaration to name the correct inline namespace within the qualifier.
3227static void adjustDeclContextForDeclaratorDecl(DeclaratorDecl *NewD,
                                             DeclaratorDecl *OldD) {
// The only case where we need to update the DeclContext is when
// redeclaration lookup for a qualified name finds a declaration
// in an inline namespace within the context named by the qualifier:
//
//   inline namespace N { int f(); }
//   int ::f(); // Sema DC needs adjusting from :: to N::.
//
// For unqualified declarations, the semantic context *can* change
// along the redeclaration chain (for local extern declarations,
// extern "C" declarations, and friend declarations in particular).
if (!NewD->getQualifier())
  return;

// NewD is probably already in the right context.
auto *NamedDC = NewD->getDeclContext()->getRedeclContext();
auto *SemaDC = OldD->getDeclContext()->getRedeclContext();
if (NamedDC->Equals(SemaDC))
  return;

assert((NamedDC->InEnclosingNamespaceSetOf(SemaDC) ||((void)0)
        NewD->isInvalidDecl() || OldD->isInvalidDecl()) &&((void)0)
       "unexpected context for redeclaration")((void)0);

auto *LexDC = NewD->getLexicalDeclContext();
auto FixSemaDC = [=](NamedDecl *D) {
  if (!D)
    return;
  D->setDeclContext(SemaDC);
  D->setLexicalDeclContext(LexDC);
};

FixSemaDC(NewD);
if (auto *FD = dyn_cast<FunctionDecl>(NewD))
  FixSemaDC(FD->getDescribedFunctionTemplate());
else if (auto *VD = dyn_cast<VarDecl>(NewD))
  FixSemaDC(VD->getDescribedVarTemplate());
3265}

3267/// MergeFunctionDecl - We just parsed a function 'New' from
3268/// declarator D which has the same name and scope as a previous
3269/// declaration 'Old'.  Figure out how to resolve this situation,
3270/// merging decls or emitting diagnostics as appropriate.
3271///
3272/// In C++, New and Old must be declarations that are not
3273/// overloaded. Use IsOverload to determine whether New and Old are
3274/// overloaded, and to select the Old declaration that New should be
3275/// merged with.
3276///
3277/// Returns true if there was an error, false otherwise.
3278bool Sema::MergeFunctionDecl(FunctionDecl *New, NamedDecl *&OldD,
                           Scope *S, bool MergeTypeWithOld) {
// Verify the old decl was also a function.
FunctionDecl *Old = OldD->getAsFunction();
if (!Old) {
  if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(OldD)) {
    if (New->getFriendObjectKind()) {
      Diag(New->getLocation(), diag::err_using_decl_friend);
      Diag(Shadow->getTargetDecl()->getLocation(),
           diag::note_using_decl_target);
      Diag(Shadow->getIntroducer()->getLocation(), diag::note_using_decl)
          << 0;
      return true;
    }

    // Check whether the two declarations might declare the same function or
    // function template.
    if (FunctionTemplateDecl *NewTemplate =
            New->getDescribedFunctionTemplate()) {
      if (checkUsingShadowRedecl<FunctionTemplateDecl>(*this, Shadow,
                                                       NewTemplate))
        return true;
      OldD = Old = cast<FunctionTemplateDecl>(Shadow->getTargetDecl())
                       ->getAsFunction();
    } else {
      if (checkUsingShadowRedecl<FunctionDecl>(*this, Shadow, New))
        return true;
      OldD = Old = cast<FunctionDecl>(Shadow->getTargetDecl());
    }
  } else {
    Diag(New->getLocation(), diag::err_redefinition_different_kind)
      << New->getDeclName();
    notePreviousDefinition(OldD, New->getLocation());
    return true;
  }
}

// If the old declaration was found in an inline namespace and the new
// declaration was qualified, update the DeclContext to match.
adjustDeclContextForDeclaratorDecl(New, Old);

// If the old declaration is invalid, just give up here.
if (Old->isInvalidDecl())
  return true;

// Disallow redeclaration of some builtins.
if (!getASTContext().canBuiltinBeRedeclared(Old)) {
  Diag(New->getLocation(), diag::err_builtin_redeclare) << Old->getDeclName();
  Diag(Old->getLocation(), diag::note_previous_builtin_declaration)
      << Old << Old->getType();
  return true;
}

diag::kind PrevDiag;
SourceLocation OldLocation;
std::tie(PrevDiag, OldLocation) =
    getNoteDiagForInvalidRedeclaration(Old, New);

// Don't complain about this if we're in GNU89 mode and the old function
// is an extern inline function.
// Don't complain about specializations. They are not supposed to have
// storage classes.
if (!isa<CXXMethodDecl>(New) && !isa<CXXMethodDecl>(Old) &&
    New->getStorageClass() == SC_Static &&
    Old->hasExternalFormalLinkage() &&
    !New->getTemplateSpecializationInfo() &&
    !canRedefineFunction(Old, getLangOpts())) {
  if (getLangOpts().MicrosoftExt) {
    Diag(New->getLocation(), diag::ext_static_non_static) << New;
    Diag(OldLocation, PrevDiag);
  } else {
    Diag(New->getLocation(), diag::err_static_non_static) << New;
    Diag(OldLocation, PrevDiag);
    return true;
  }
}

if (New->hasAttr<InternalLinkageAttr>() &&
    !Old->hasAttr<InternalLinkageAttr>()) {
  Diag(New->getLocation(), diag::err_internal_linkage_redeclaration)
      << New->getDeclName();
  notePreviousDefinition(Old, New->getLocation());
  New->dropAttr<InternalLinkageAttr>();
}

if (CheckRedeclarationModuleOwnership(New, Old))
  return true;

if (!getLangOpts().CPlusPlus) {
  bool OldOvl = Old->hasAttr<OverloadableAttr>();
  if (OldOvl != New->hasAttr<OverloadableAttr>() && !Old->isImplicit()) {
    Diag(New->getLocation(), diag::err_attribute_overloadable_mismatch)
      << New << OldOvl;

    // Try our best to find a decl that actually has the overloadable
    // attribute for the note. In most cases (e.g. programs with only one
    // broken declaration/definition), this won't matter.
    //
    // FIXME: We could do this if we juggled some extra state in
    // OverloadableAttr, rather than just removing it.
    const Decl *DiagOld = Old;
    if (OldOvl) {
      auto OldIter = llvm::find_if(Old->redecls(), [](const Decl *D) {
        const auto *A = D->getAttr<OverloadableAttr>();
        return A && !A->isImplicit();
      });
      // If we've implicitly added *all* of the overloadable attrs to this
      // chain, emitting a "previous redecl" note is pointless.
      DiagOld = OldIter == Old->redecls_end() ? nullptr : *OldIter;
    }

    if (DiagOld)
      Diag(DiagOld->getLocation(),
           diag::note_attribute_overloadable_prev_overload)
        << OldOvl;

    if (OldOvl)
      New->addAttr(OverloadableAttr::CreateImplicit(Context));
    else
      New->dropAttr<OverloadableAttr>();
  }
}

// If a function is first declared with a calling convention, but is later
// declared or defined without one, all following decls assume the calling
// convention of the first.
//
// It's OK if a function is first declared without a calling convention,
// but is later declared or defined with the default calling convention.
//
// To test if either decl has an explicit calling convention, we look for
// AttributedType sugar nodes on the type as written.  If they are missing or
// were canonicalized away, we assume the calling convention was implicit.
//
// Note also that we DO NOT return at this point, because we still have
// other tests to run.
QualType OldQType = Context.getCanonicalType(Old->getType());
QualType NewQType = Context.getCanonicalType(New->getType());
const FunctionType *OldType = cast<FunctionType>(OldQType);
const FunctionType *NewType = cast<FunctionType>(NewQType);
FunctionType::ExtInfo OldTypeInfo = OldType->getExtInfo();
FunctionType::ExtInfo NewTypeInfo = NewType->getExtInfo();
bool RequiresAdjustment = false;

if (OldTypeInfo.getCC() != NewTypeInfo.getCC()) {
  FunctionDecl *First = Old->getFirstDecl();
  const FunctionType *FT =
      First->getType().getCanonicalType()->castAs<FunctionType>();
  FunctionType::ExtInfo FI = FT->getExtInfo();
  bool NewCCExplicit = getCallingConvAttributedType(New->getType());
  if (!NewCCExplicit) {
    // Inherit the CC from the previous declaration if it was specified
    // there but not here.
    NewTypeInfo = NewTypeInfo.withCallingConv(OldTypeInfo.getCC());
    RequiresAdjustment = true;
  } else if (Old->getBuiltinID()) {
    // Builtin attribute isn't propagated to the new one yet at this point,
    // so we check if the old one is a builtin.

    // Calling Conventions on a Builtin aren't really useful and setting a
    // default calling convention and cdecl'ing some builtin redeclarations is
    // common, so warn and ignore the calling convention on the redeclaration.
    Diag(New->getLocation(), diag::warn_cconv_unsupported)
        << FunctionType::getNameForCallConv(NewTypeInfo.getCC())
        << (int)CallingConventionIgnoredReason::BuiltinFunction;
    NewTypeInfo = NewTypeInfo.withCallingConv(OldTypeInfo.getCC());
    RequiresAdjustment = true;
  } else {
    // Calling conventions aren't compatible, so complain.
    bool FirstCCExplicit = getCallingConvAttributedType(First->getType());
    Diag(New->getLocation(), diag::err_cconv_change)
      << FunctionType::getNameForCallConv(NewTypeInfo.getCC())
      << !FirstCCExplicit
      << (!FirstCCExplicit ? "" :
          FunctionType::getNameForCallConv(FI.getCC()));

    // Put the note on the first decl, since it is the one that matters.
    Diag(First->getLocation(), diag::note_previous_declaration);
    return true;
  }
}

// FIXME: diagnose the other way around?
if (OldTypeInfo.getNoReturn() && !NewTypeInfo.getNoReturn()) {
  NewTypeInfo = NewTypeInfo.withNoReturn(true);
  RequiresAdjustment = true;
}

// Merge regparm attribute.
if (OldTypeInfo.getHasRegParm() != NewTypeInfo.getHasRegParm() ||
    OldTypeInfo.getRegParm() != NewTypeInfo.getRegParm()) {
  if (NewTypeInfo.getHasRegParm()) {
    Diag(New->getLocation(), diag::err_regparm_mismatch)
      << NewType->getRegParmType()
      << OldType->getRegParmType();
    Diag(OldLocation, diag::note_previous_declaration);
    return true;
  }

  NewTypeInfo = NewTypeInfo.withRegParm(OldTypeInfo.getRegParm());
  RequiresAdjustment = true;
}

// Merge ns_returns_retained attribute.
if (OldTypeInfo.getProducesResult() != NewTypeInfo.getProducesResult()) {
  if (NewTypeInfo.getProducesResult()) {
    Diag(New->getLocation(), diag::err_function_attribute_mismatch)
        << "'ns_returns_retained'";
    Diag(OldLocation, diag::note_previous_declaration);
    return true;
  }

  NewTypeInfo = NewTypeInfo.withProducesResult(true);
  RequiresAdjustment = true;
}

if (OldTypeInfo.getNoCallerSavedRegs() !=
    NewTypeInfo.getNoCallerSavedRegs()) {
  if (NewTypeInfo.getNoCallerSavedRegs()) {
    AnyX86NoCallerSavedRegistersAttr *Attr =
      New->getAttr<AnyX86NoCallerSavedRegistersAttr>();
    Diag(New->getLocation(), diag::err_function_attribute_mismatch) << Attr;
    Diag(OldLocation, diag::note_previous_declaration);
    return true;
  }

  NewTypeInfo = NewTypeInfo.withNoCallerSavedRegs(true);
  RequiresAdjustment = true;
}

if (RequiresAdjustment) {
  const FunctionType *AdjustedType = New->getType()->getAs<FunctionType>();
  AdjustedType = Context.adjustFunctionType(AdjustedType, NewTypeInfo);
  New->setType(QualType(AdjustedType, 0));
  NewQType = Context.getCanonicalType(New->getType());
}

// If this redeclaration makes the function inline, we may need to add it to
// UndefinedButUsed.
if (!Old->isInlined() && New->isInlined() &&
    !New->hasAttr<GNUInlineAttr>() &&
    !getLangOpts().GNUInline &&
    Old->isUsed(false) &&
    !Old->isDefined() && !New->isThisDeclarationADefinition())
  UndefinedButUsed.insert(std::make_pair(Old->getCanonicalDecl(),
                                         SourceLocation()));

// If this redeclaration makes it newly gnu_inline, we don't want to warn
// about it.
if (New->hasAttr<GNUInlineAttr>() &&
    Old->isInlined() && !Old->hasAttr<GNUInlineAttr>()) {
  UndefinedButUsed.erase(Old->getCanonicalDecl());
}

// If pass_object_size params don't match up perfectly, this isn't a valid
// redeclaration.
if (Old->getNumParams() > 0 && Old->getNumParams() == New->getNumParams() &&
    !hasIdenticalPassObjectSizeAttrs(Old, New)) {
  Diag(New->getLocation(), diag::err_different_pass_object_size_params)
      << New->getDeclName();
  Diag(OldLocation, PrevDiag) << Old << Old->getType();
  return true;
}

if (getLangOpts().CPlusPlus) {
  // C++1z [over.load]p2
  //   Certain function declarations cannot be overloaded:
  //     -- Function declarations that differ only in the return type,
  //        the exception specification, or both cannot be overloaded.

  // Check the exception specifications match. This may recompute the type of
  // both Old and New if it resolved exception specifications, so grab the
  // types again after this. Because this updates the type, we do this before
  // any of the other checks below, which may update the "de facto" NewQType
  // but do not necessarily update the type of New.
  if (CheckEquivalentExceptionSpec(Old, New))
    return true;
  OldQType = Context.getCanonicalType(Old->getType());
  NewQType = Context.getCanonicalType(New->getType());

  // Go back to the type source info to compare the declared return types,
  // per C++1y [dcl.type.auto]p13:
  //   Redeclarations or specializations of a function or function template
  //   with a declared return type that uses a placeholder type shall also
  //   use that placeholder, not a deduced type.
  QualType OldDeclaredReturnType = Old->getDeclaredReturnType();
  QualType NewDeclaredReturnType = New->getDeclaredReturnType();
  if (!Context.hasSameType(OldDeclaredReturnType, NewDeclaredReturnType) &&
      canFullyTypeCheckRedeclaration(New, Old, NewDeclaredReturnType,
                                     OldDeclaredReturnType)) {
    QualType ResQT;
    if (NewDeclaredReturnType->isObjCObjectPointerType() &&
        OldDeclaredReturnType->isObjCObjectPointerType())
      // FIXME: This does the wrong thing for a deduced return type.
      ResQT = Context.mergeObjCGCQualifiers(NewQType, OldQType);
    if (ResQT.isNull()) {
      if (New->isCXXClassMember() && New->isOutOfLine())
        Diag(New->getLocation(), diag::err_member_def_does_not_match_ret_type)
            << New << New->getReturnTypeSourceRange();
      else
        Diag(New->getLocation(), diag::err_ovl_diff_return_type)
            << New->getReturnTypeSourceRange();
      Diag(OldLocation, PrevDiag) << Old << Old->getType()
                                  << Old->getReturnTypeSourceRange();
      return true;
    }
    else
      NewQType = ResQT;
  }

  QualType OldReturnType = OldType->getReturnType();
  QualType NewReturnType = cast<FunctionType>(NewQType)->getReturnType();
  if (OldReturnType != NewReturnType) {
    // If this function has a deduced return type and has already been
    // defined, copy the deduced value from the old declaration.
    AutoType *OldAT = Old->getReturnType()->getContainedAutoType();
    if (OldAT && OldAT->isDeduced()) {
      New->setType(
          SubstAutoType(New->getType(),
                        OldAT->isDependentType() ? Context.DependentTy
                                                 : OldAT->getDeducedType()));
      NewQType = Context.getCanonicalType(
          SubstAutoType(NewQType,
                        OldAT->isDependentType() ? Context.DependentTy
                                                 : OldAT->getDeducedType()));
    }
  }

  const CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
  CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
  if (OldMethod && NewMethod) {
    // Preserve triviality.
    NewMethod->setTrivial(OldMethod->isTrivial());

    // MSVC allows explicit template specialization at class scope:
    // 2 CXXMethodDecls referring to the same function will be injected.
    // We don't want a redeclaration error.
    bool IsClassScopeExplicitSpecialization =
                            OldMethod->isFunctionTemplateSpecialization() &&
                            NewMethod->isFunctionTemplateSpecialization();
    bool isFriend = NewMethod->getFriendObjectKind();

    if (!isFriend && NewMethod->getLexicalDeclContext()->isRecord() &&
        !IsClassScopeExplicitSpecialization) {
      //    -- Member function declarations with the same name and the
      //       same parameter types cannot be overloaded if any of them
      //       is a static member function declaration.
      if (OldMethod->isStatic() != NewMethod->isStatic()) {
        Diag(New->getLocation(), diag::err_ovl_static_nonstatic_member);
        Diag(OldLocation, PrevDiag) << Old << Old->getType();
        return true;
      }

      // C++ [class.mem]p1:
      //   [...] A member shall not be declared twice in the
      //   member-specification, except that a nested class or member
      //   class template can be declared and then later defined.
      if (!inTemplateInstantiation()) {
        unsigned NewDiag;
        if (isa<CXXConstructorDecl>(OldMethod))
          NewDiag = diag::err_constructor_redeclared;
        else if (isa<CXXDestructorDecl>(NewMethod))
          NewDiag = diag::err_destructor_redeclared;
        else if (isa<CXXConversionDecl>(NewMethod))
          NewDiag = diag::err_conv_function_redeclared;
        else
          NewDiag = diag::err_member_redeclared;

        Diag(New->getLocation(), NewDiag);
      } else {
        Diag(New->getLocation(), diag::err_member_redeclared_in_instantiation)
          << New << New->getType();
      }
      Diag(OldLocation, PrevDiag) << Old << Old->getType();
      return true;

    // Complain if this is an explicit declaration of a special
    // member that was initially declared implicitly.
    //
    // As an exception, it's okay to befriend such methods in order
    // to permit the implicit constructor/destructor/operator calls.
    } else if (OldMethod->isImplicit()) {
      if (isFriend) {
        NewMethod->setImplicit();
      } else {
        Diag(NewMethod->getLocation(),
             diag::err_definition_of_implicitly_declared_member)
          << New << getSpecialMember(OldMethod);
        return true;
      }
    } else if (OldMethod->getFirstDecl()->isExplicitlyDefaulted() && !isFriend) {
      Diag(NewMethod->getLocation(),
           diag::err_definition_of_explicitly_defaulted_member)
        << getSpecialMember(OldMethod);
      return true;
    }
  }

  // C++11 [dcl.attr.noreturn]p1:
  //   The first declaration of a function shall specify the noreturn
  //   attribute if any declaration of that function specifies the noreturn
  //   attribute.
  const CXX11NoReturnAttr *NRA = New->getAttr<CXX11NoReturnAttr>();
  if (NRA && !Old->hasAttr<CXX11NoReturnAttr>()) {
    Diag(NRA->getLocation(), diag::err_noreturn_missing_on_first_decl);
    Diag(Old->getFirstDecl()->getLocation(),
         diag::note_noreturn_missing_first_decl);
  }

  // C++11 [dcl.attr.depend]p2:
  //   The first declaration of a function shall specify the
  //   carries_dependency attribute for its declarator-id if any declaration
  //   of the function specifies the carries_dependency attribute.
  const CarriesDependencyAttr *CDA = New->getAttr<CarriesDependencyAttr>();
  if (CDA && !Old->hasAttr<CarriesDependencyAttr>()) {
    Diag(CDA->getLocation(),
         diag::err_carries_dependency_missing_on_first_decl) << 0/*Function*/;
    Diag(Old->getFirstDecl()->getLocation(),
         diag::note_carries_dependency_missing_first_decl) << 0/*Function*/;
  }

  // (C++98 8.3.5p3):
  //   All declarations for a function shall agree exactly in both the
  //   return type and the parameter-type-list.
  // We also want to respect all the extended bits except noreturn.

  // noreturn should now match unless the old type info didn't have it.
  QualType OldQTypeForComparison = OldQType;
  if (!OldTypeInfo.getNoReturn() && NewTypeInfo.getNoReturn()) {
    auto *OldType = OldQType->castAs<FunctionProtoType>();
    const FunctionType *OldTypeForComparison
      = Context.adjustFunctionType(OldType, OldTypeInfo.withNoReturn(true));
    OldQTypeForComparison = QualType(OldTypeForComparison, 0);
    assert(OldQTypeForComparison.isCanonical())((void)0);
  }

  if (haveIncompatibleLanguageLinkages(Old, New)) {
    // As a special case, retain the language linkage from previous
    // declarations of a friend function as an extension.
    //
    // This liberal interpretation of C++ [class.friend]p3 matches GCC/MSVC
    // and is useful because there's otherwise no way to specify language
    // linkage within class scope.
    //
    // Check cautiously as the friend object kind isn't yet complete.
    if (New->getFriendObjectKind() != Decl::FOK_None) {
      Diag(New->getLocation(), diag::ext_retained_language_linkage) << New;
      Diag(OldLocation, PrevDiag);
    } else {
      Diag(New->getLocation(), diag::err_different_language_linkage) << New;
      Diag(OldLocation, PrevDiag);
      return true;
    }
  }

  // If the function types are compatible, merge the declarations. Ignore the
  // exception specifier because it was already checked above in
  // CheckEquivalentExceptionSpec, and we don't want follow-on diagnostics
  // about incompatible types under -fms-compatibility.
  if (Context.hasSameFunctionTypeIgnoringExceptionSpec(OldQTypeForComparison,
                                                       NewQType))
    return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);

  // If the types are imprecise (due to dependent constructs in friends or
  // local extern declarations), it's OK if they differ. We'll check again
  // during instantiation.
  if (!canFullyTypeCheckRedeclaration(New, Old, NewQType, OldQType))
    return false;

  // Fall through for conflicting redeclarations and redefinitions.
}

// C: Function types need to be compatible, not identical. This handles
// duplicate function decls like "void f(int); void f(enum X);" properly.
if (!getLangOpts().CPlusPlus &&
    Context.typesAreCompatible(OldQType, NewQType)) {
  const FunctionType *OldFuncType = OldQType->getAs<FunctionType>();
  const FunctionType *NewFuncType = NewQType->getAs<FunctionType>();
  const FunctionProtoType *OldProto = nullptr;
  if (MergeTypeWithOld && isa<FunctionNoProtoType>(NewFuncType) &&
      (OldProto = dyn_cast<FunctionProtoType>(OldFuncType))) {
    // The old declaration provided a function prototype, but the
    // new declaration does not. Merge in the prototype.
    assert(!OldProto->hasExceptionSpec() && "Exception spec in C")((void)0);
    SmallVector<QualType, 16> ParamTypes(OldProto->param_types());
    NewQType =
        Context.getFunctionType(NewFuncType->getReturnType(), ParamTypes,
                                OldProto->getExtProtoInfo());
    New->setType(NewQType);
    New->setHasInheritedPrototype();

    // Synthesize parameters with the same types.
    SmallVector<ParmVarDecl*, 16> Params;
    for (const auto &ParamType : OldProto->param_types()) {
      ParmVarDecl *Param = ParmVarDecl::Create(Context, New, SourceLocation(),
                                               SourceLocation(), nullptr,
                                               ParamType, /*TInfo=*/nullptr,
                                               SC_None, nullptr);
      Param->setScopeInfo(0, Params.size());
      Param->setImplicit();
      Params.push_back(Param);
    }

    New->setParams(Params);
  }

  return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
}

// Check if the function types are compatible when pointer size address
// spaces are ignored.
if (Context.hasSameFunctionTypeIgnoringPtrSizes(OldQType, NewQType))
  return false;

// GNU C permits a K&R definition to follow a prototype declaration
// if the declared types of the parameters in the K&R definition
// match the types in the prototype declaration, even when the
// promoted types of the parameters from the K&R definition differ
// from the types in the prototype. GCC then keeps the types from
// the prototype.
//
// If a variadic prototype is followed by a non-variadic K&R definition,
// the K&R definition becomes variadic.  This is sort of an edge case, but
// it's legal per the standard depending on how you read C99 6.7.5.3p15 and
// C99 6.9.1p8.
if (!getLangOpts().CPlusPlus &&
    Old->hasPrototype() && !New->hasPrototype() &&
    New->getType()->getAs<FunctionProtoType>() &&
    Old->getNumParams() == New->getNumParams()) {
  SmallVector<QualType, 16> ArgTypes;
  SmallVector<GNUCompatibleParamWarning, 16> Warnings;
  const FunctionProtoType *OldProto
    = Old->getType()->getAs<FunctionProtoType>();
  const FunctionProtoType *NewProto
    = New->getType()->getAs<FunctionProtoType>();

  // Determine whether this is the GNU C extension.
  QualType MergedReturn = Context.mergeTypes(OldProto->getReturnType(),
                                             NewProto->getReturnType());
  bool LooseCompatible = !MergedReturn.isNull();
  for (unsigned Idx = 0, End = Old->getNumParams();
       LooseCompatible && Idx != End; ++Idx) {
    ParmVarDecl *OldParm = Old->getParamDecl(Idx);
    ParmVarDecl *NewParm = New->getParamDecl(Idx);
    if (Context.typesAreCompatible(OldParm->getType(),
                                   NewProto->getParamType(Idx))) {
      ArgTypes.push_back(NewParm->getType());
    } else if (Context.typesAreCompatible(OldParm->getType(),
                                          NewParm->getType(),
                                          /*CompareUnqualified=*/true)) {
      GNUCompatibleParamWarning Warn = { OldParm, NewParm,
                                         NewProto->getParamType(Idx) };
      Warnings.push_back(Warn);
      ArgTypes.push_back(NewParm->getType());
    } else
      LooseCompatible = false;
  }

  if (LooseCompatible) {
    for (unsigned Warn = 0; Warn < Warnings.size(); ++Warn) {
      Diag(Warnings[Warn].NewParm->getLocation(),
           diag::ext_param_promoted_not_compatible_with_prototype)
        << Warnings[Warn].PromotedType
        << Warnings[Warn].OldParm->getType();
      if (Warnings[Warn].OldParm->getLocation().isValid())
        Diag(Warnings[Warn].OldParm->getLocation(),
             diag::note_previous_declaration);
    }

    if (MergeTypeWithOld)
      New->setType(Context.getFunctionType(MergedReturn, ArgTypes,
                                           OldProto->getExtProtoInfo()));
    return MergeCompatibleFunctionDecls(New, Old, S, MergeTypeWithOld);
  }

  // Fall through to diagnose conflicting types.
}

// A function that has already been declared has been redeclared or
// defined with a different type; show an appropriate diagnostic.

// If the previous declaration was an implicitly-generated builtin
// declaration, then at the very least we should use a specialized note.
unsigned BuiltinID;
if (Old->isImplicit() && (BuiltinID = Old->getBuiltinID())) {
  // If it's actually a library-defined builtin function like 'malloc'
  // or 'printf', just warn about the incompatible redeclaration.
  if (Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) {
    Diag(New->getLocation(), diag::warn_redecl_library_builtin) << New;
    Diag(OldLocation, diag::note_previous_builtin_declaration)
      << Old << Old->getType();
    return false;
  }

  PrevDiag = diag::note_previous_builtin_declaration;
}

Diag(New->getLocation(), diag::err_conflicting_types) << New->getDeclName();
Diag(OldLocation, PrevDiag) << Old << Old->getType();
return true;
3878}

3880/// Completes the merge of two function declarations that are
3881/// known to be compatible.
3882///
3883/// This routine handles the merging of attributes and other
3884/// properties of function declarations from the old declaration to
3885/// the new declaration, once we know that New is in fact a
3886/// redeclaration of Old.
3887///
3888/// \returns false
3889bool Sema::MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
                                      Scope *S, bool MergeTypeWithOld) {
// Merge the attributes
mergeDeclAttributes(New, Old);

// Merge "pure" flag.
if (Old->isPure())
  New->setPure();

// Merge "used" flag.
if (Old->getMostRecentDecl()->isUsed(false))
  New->setIsUsed();

// Merge attributes from the parameters.  These can mismatch with K&R
// declarations.
if (New->getNumParams() == Old->getNumParams())
    for (unsigned i = 0, e = New->getNumParams(); i != e; ++i) {
      ParmVarDecl *NewParam = New->getParamDecl(i);
      ParmVarDecl *OldParam = Old->getParamDecl(i);
      mergeParamDeclAttributes(NewParam, OldParam, *this);
      mergeParamDeclTypes(NewParam, OldParam, *this);
    }

if (getLangOpts().CPlusPlus)
  return MergeCXXFunctionDecl(New, Old, S);

// Merge the function types so the we get the composite types for the return
// and argument types. Per C11 6.2.7/4, only update the type if the old decl
// was visible.
QualType Merged = Context.mergeTypes(Old->getType(), New->getType());
if (!Merged.isNull() && MergeTypeWithOld)
  New->setType(Merged);

return false;
3923}

3925void Sema::mergeObjCMethodDecls(ObjCMethodDecl *newMethod,
                              ObjCMethodDecl *oldMethod) {
// Merge the attributes, including deprecated/unavailable
AvailabilityMergeKind MergeKind =
    isa<ObjCProtocolDecl>(oldMethod->getDeclContext())
        ? (oldMethod->isOptional() ? AMK_OptionalProtocolImplementation
                                   : AMK_ProtocolImplementation)
        : isa<ObjCImplDecl>(newMethod->getDeclContext()) ? AMK_Redeclaration
                                                         : AMK_Override;

mergeDeclAttributes(newMethod, oldMethod, MergeKind);

// Merge attributes from the parameters.
ObjCMethodDecl::param_const_iterator oi = oldMethod->param_begin(),
                                     oe = oldMethod->param_end();
for (ObjCMethodDecl::param_iterator
       ni = newMethod->param_begin(), ne = newMethod->param_end();
     ni != ne && oi != oe; ++ni, ++oi)
  mergeParamDeclAttributes(*ni, *oi, *this);

CheckObjCMethodOverride(newMethod, oldMethod);
3946}

3948static void diagnoseVarDeclTypeMismatch(Sema &S, VarDecl *New, VarDecl* Old) {
assert(!S.Context.hasSameType(New->getType(), Old->getType()))((void)0);

S.Diag(New->getLocation(), New->isThisDeclarationADefinition()
       ? diag::err_redefinition_different_type
       : diag::err_redeclaration_different_type)
  << New->getDeclName() << New->getType() << Old->getType();

diag::kind PrevDiag;
SourceLocation OldLocation;
std::tie(PrevDiag, OldLocation)
  = getNoteDiagForInvalidRedeclaration(Old, New);
S.Diag(OldLocation, PrevDiag);
New->setInvalidDecl();
3962}

3964/// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
3965/// scope as a previous declaration 'Old'.  Figure out how to merge their types,
3966/// emitting diagnostics as appropriate.
3967///
3968/// Declarations using the auto type specifier (C++ [decl.spec.auto]) call back
3969/// to here in AddInitializerToDecl. We can't check them before the initializer
3970/// is attached.
3971void Sema::MergeVarDeclTypes(VarDecl *New, VarDecl *Old,
                           bool MergeTypeWithOld) {
if (New->isInvalidDecl() || Old->isInvalidDecl())
  return;

QualType MergedT;
if (getLangOpts().CPlusPlus) {
  if (New->getType()->isUndeducedType()) {
    // We don't know what the new type is until the initializer is attached.
    return;
  } else if (Context.hasSameType(New->getType(), Old->getType())) {
    // These could still be something that needs exception specs checked.
    return MergeVarDeclExceptionSpecs(New, Old);
  }
  // C++ [basic.link]p10:
  //   [...] the types specified by all declarations referring to a given
  //   object or function shall be identical, except that declarations for an
  //   array object can specify array types that differ by the presence or
  //   absence of a major array bound (8.3.4).
  else if (Old->getType()->isArrayType() && New->getType()->isArrayType()) {
    const ArrayType *OldArray = Context.getAsArrayType(Old->getType());
    const ArrayType *NewArray = Context.getAsArrayType(New->getType());

    // We are merging a variable declaration New into Old. If it has an array
    // bound, and that bound differs from Old's bound, we should diagnose the
    // mismatch.
    if (!NewArray->isIncompleteArrayType() && !NewArray->isDependentType()) {
      for (VarDecl *PrevVD = Old->getMostRecentDecl(); PrevVD;
           PrevVD = PrevVD->getPreviousDecl()) {
        QualType PrevVDTy = PrevVD->getType();
        if (PrevVDTy->isIncompleteArrayType() || PrevVDTy->isDependentType())
          continue;

        if (!Context.hasSameType(New->getType(), PrevVDTy))
          return diagnoseVarDeclTypeMismatch(*this, New, PrevVD);
      }
    }

    if (OldArray->isIncompleteArrayType() && NewArray->isArrayType()) {
      if (Context.hasSameType(OldArray->getElementType(),
                              NewArray->getElementType()))
        MergedT = New->getType();
    }
    // FIXME: Check visibility. New is hidden but has a complete type. If New
    // has no array bound, it should not inherit one from Old, if Old is not
    // visible.
    else if (OldArray->isArrayType() && NewArray->isIncompleteArrayType()) {
      if (Context.hasSameType(OldArray->getElementType(),
                              NewArray->getElementType()))
        MergedT = Old->getType();
    }
  }
  else if (New->getType()->isObjCObjectPointerType() &&
             Old->getType()->isObjCObjectPointerType()) {
    MergedT = Context.mergeObjCGCQualifiers(New->getType(),
                                            Old->getType());
  }
} else {
  // C 6.2.7p2:
  //   All declarations that refer to the same object or function shall have
  //   compatible type.
  MergedT = Context.mergeTypes(New->getType(), Old->getType());
}
if (MergedT.isNull()) {
  // It's OK if we couldn't merge types if either type is dependent, for a
  // block-scope variable. In other cases (static data members of class
  // templates, variable templates, ...), we require the types to be
  // equivalent.
  // FIXME: The C++ standard doesn't say anything about this.
  if ((New->getType()->isDependentType() ||
       Old->getType()->isDependentType()) && New->isLocalVarDecl()) {
    // If the old type was dependent, we can't merge with it, so the new type
    // becomes dependent for now. We'll reproduce the original type when we
    // instantiate the TypeSourceInfo for the variable.
    if (!New->getType()->isDependentType() && MergeTypeWithOld)
      New->setType(Context.DependentTy);
    return;
  }
  return diagnoseVarDeclTypeMismatch(*this, New, Old);
}

// Don't actually update the type on the new declaration if the old
// declaration was an extern declaration in a different scope.
if (MergeTypeWithOld)
  New->setType(MergedT);
4056}

4058static bool mergeTypeWithPrevious(Sema &S, VarDecl *NewVD, VarDecl *OldVD,
                                LookupResult &Previous) {
// C11 6.2.7p4:
//   For an identifier with internal or external linkage declared
//   in a scope in which a prior declaration of that identifier is
//   visible, if the prior declaration specifies internal or
//   external linkage, the type of the identifier at the later
//   declaration becomes the composite type.
//
// If the variable isn't visible, we do not merge with its type.
if (Previous.isShadowed())
  return false;

if (S.getLangOpts().CPlusPlus) {
  // C++11 [dcl.array]p3:
  //   If there is a preceding declaration of the entity in the same
  //   scope in which the bound was specified, an omitted array bound
  //   is taken to be the same as in that earlier declaration.
  return NewVD->isPreviousDeclInSameBlockScope() ||
         (!OldVD->getLexicalDeclContext()->isFunctionOrMethod() &&
          !NewVD->getLexicalDeclContext()->isFunctionOrMethod());
} else {
  // If the old declaration was function-local, don't merge with its
  // type unless we're in the same function.
  return !OldVD->getLexicalDeclContext()->isFunctionOrMethod() ||
         OldVD->getLexicalDeclContext() == NewVD->getLexicalDeclContext();
}
4085}

4087/// MergeVarDecl - We just parsed a variable 'New' which has the same name
4088/// and scope as a previous declaration 'Old'.  Figure out how to resolve this
4089/// situation, merging decls or emitting diagnostics as appropriate.
4090///
4091/// Tentative definition rules (C99 6.9.2p2) are checked by
4092/// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
4093/// definitions here, since the initializer hasn't been attached.
4094///
4095void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) {
// If the new decl is already invalid, don't do any other checking.
if (New->isInvalidDecl())
  return;

if (!shouldLinkPossiblyHiddenDecl(Previous, New))
  return;

VarTemplateDecl *NewTemplate = New->getDescribedVarTemplate();

// Verify the old decl was also a variable or variable template.
VarDecl *Old = nullptr;
VarTemplateDecl *OldTemplate = nullptr;
if (Previous.isSingleResult()) {
  if (NewTemplate) {
    OldTemplate = dyn_cast<VarTemplateDecl>(Previous.getFoundDecl());
    Old = OldTemplate ? OldTemplate->getTemplatedDecl() : nullptr;

    if (auto *Shadow =
            dyn_cast<UsingShadowDecl>(Previous.getRepresentativeDecl()))
      if (checkUsingShadowRedecl<VarTemplateDecl>(*this, Shadow, NewTemplate))
        return New->setInvalidDecl();
  } else {
    Old = dyn_cast<VarDecl>(Previous.getFoundDecl());

    if (auto *Shadow =
            dyn_cast<UsingShadowDecl>(Previous.getRepresentativeDecl()))
      if (checkUsingShadowRedecl<VarDecl>(*this, Shadow, New))
        return New->setInvalidDecl();
  }
}
if (!Old) {
  Diag(New->getLocation(), diag::err_redefinition_different_kind)
      << New->getDeclName();
  notePreviousDefinition(Previous.getRepresentativeDecl(),
                         New->getLocation());
  return New->setInvalidDecl();
}

// If the old declaration was found in an inline namespace and the new
// declaration was qualified, update the DeclContext to match.
adjustDeclContextForDeclaratorDecl(New, Old);

// Ensure the template parameters are compatible.
if (NewTemplate &&
    !TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
                                    OldTemplate->getTemplateParameters(),
                                    /*Complain=*/true, TPL_TemplateMatch))
  return New->setInvalidDecl();

// C++ [class.mem]p1:
//   A member shall not be declared twice in the member-specification [...]
//
// Here, we need only consider static data members.
if (Old->isStaticDataMember() && !New->isOutOfLine()) {
  Diag(New->getLocation(), diag::err_duplicate_member)
    << New->getIdentifier();
  Diag(Old->getLocation(), diag::note_previous_declaration);
  New->setInvalidDecl();
}

mergeDeclAttributes(New, Old);
// Warn if an already-declared variable is made a weak_import in a subsequent
// declaration
if (New->hasAttr<WeakImportAttr>() &&
    Old->getStorageClass() == SC_None &&
    !Old->hasAttr<WeakImportAttr>()) {
  Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
  notePreviousDefinition(Old, New->getLocation());
  // Remove weak_import attribute on new declaration.
  New->dropAttr<WeakImportAttr>();
}

if (New->hasAttr<InternalLinkageAttr>() &&
    !Old->hasAttr<InternalLinkageAttr>()) {
  Diag(New->getLocation(), diag::err_internal_linkage_redeclaration)
      << New->getDeclName();
  notePreviousDefinition(Old, New->getLocation());
  New->dropAttr<InternalLinkageAttr>();
}

// Merge the types.
VarDecl *MostRecent = Old->getMostRecentDecl();
if (MostRecent != Old) {
  MergeVarDeclTypes(New, MostRecent,
                    mergeTypeWithPrevious(*this, New, MostRecent, Previous));
  if (New->isInvalidDecl())
    return;
}

MergeVarDeclTypes(New, Old, mergeTypeWithPrevious(*this, New, Old, Previous));
if (New->isInvalidDecl())
  return;

diag::kind PrevDiag;
SourceLocation OldLocation;
std::tie(PrevDiag, OldLocation) =
    getNoteDiagForInvalidRedeclaration(Old, New);

// [dcl.stc]p8: Check if we have a non-static decl followed by a static.
if (New->getStorageClass() == SC_Static &&
    !New->isStaticDataMember() &&
    Old->hasExternalFormalLinkage()) {
  if (getLangOpts().MicrosoftExt) {
    Diag(New->getLocation(), diag::ext_static_non_static)
        << New->getDeclName();
    Diag(OldLocation, PrevDiag);
  } else {
    Diag(New->getLocation(), diag::err_static_non_static)
        << New->getDeclName();
    Diag(OldLocation, PrevDiag);
    return New->setInvalidDecl();
  }
}
// C99 6.2.2p4:
//   For an identifier declared with the storage-class specifier
//   extern in a scope in which a prior declaration of that
//   identifier is visible,23) if the prior declaration specifies
//   internal or external linkage, the linkage of the identifier at
//   the later declaration is the same as the linkage specified at
//   the prior declaration. If no prior declaration is visible, or
//   if the prior declaration specifies no linkage, then the
//   identifier has external linkage.
if (New->hasExternalStorage() && Old->hasLinkage())
  /* Okay */;
else if (New->getCanonicalDecl()->getStorageClass() != SC_Static &&
         !New->isStaticDataMember() &&
         Old->getCanonicalDecl()->getStorageClass() == SC_Static) {
  Diag(New->getLocation(), diag::err_non_static_static) << New->getDeclName();
  Diag(OldLocation, PrevDiag);
  return New->setInvalidDecl();
}

// Check if extern is followed by non-extern and vice-versa.
if (New->hasExternalStorage() &&
    !Old->hasLinkage() && Old->isLocalVarDeclOrParm()) {
  Diag(New->getLocation(), diag::err_extern_non_extern) << New->getDeclName();
  Diag(OldLocation, PrevDiag);
  return New->setInvalidDecl();
}
if (Old->hasLinkage() && New->isLocalVarDeclOrParm() &&
    !New->hasExternalStorage()) {
  Diag(New->getLocation(), diag::err_non_extern_extern) << New->getDeclName();
  Diag(OldLocation, PrevDiag);
  return New->setInvalidDecl();
}

if (CheckRedeclarationModuleOwnership(New, Old))
  return;

// Variables with external linkage are analyzed in FinalizeDeclaratorGroup.

// FIXME: The test for external storage here seems wrong? We still
// need to check for mismatches.
if (!New->hasExternalStorage() && !New->isFileVarDecl() &&
    // Don't complain about out-of-line definitions of static members.
    !(Old->getLexicalDeclContext()->isRecord() &&
      !New->getLexicalDeclContext()->isRecord())) {
  Diag(New->getLocation(), diag::err_redefinition) << New->getDeclName();
  Diag(OldLocation, PrevDiag);
  return New->setInvalidDecl();
}

if (New->isInline() && !Old->getMostRecentDecl()->isInline()) {
  if (VarDecl *Def = Old->getDefinition()) {
    // C++1z [dcl.fcn.spec]p4:
    //   If the definition of a variable appears in a translation unit before
    //   its first declaration as inline, the program is ill-formed.
    Diag(New->getLocation(), diag::err_inline_decl_follows_def) << New;
    Diag(Def->getLocation(), diag::note_previous_definition);
  }
}

// If this redeclaration makes the variable inline, we may need to add it to
// UndefinedButUsed.
if (!Old->isInline() && New->isInline() && Old->isUsed(false) &&
    !Old->getDefinition() && !New->isThisDeclarationADefinition())
  UndefinedButUsed.insert(std::make_pair(Old->getCanonicalDecl(),
                                         SourceLocation()));

if (New->getTLSKind() != Old->getTLSKind()) {
  if (!Old->getTLSKind()) {
    Diag(New->getLocation(), diag::err_thread_non_thread) << New->getDeclName();
    Diag(OldLocation, PrevDiag);
  } else if (!New->getTLSKind()) {
    Diag(New->getLocation(), diag::err_non_thread_thread) << New->getDeclName();
    Diag(OldLocation, PrevDiag);
  } else {
    // Do not allow redeclaration to change the variable between requiring
    // static and dynamic initialization.
    // FIXME: GCC allows this, but uses the TLS keyword on the first
    // declaration to determine the kind. Do we need to be compatible here?
    Diag(New->getLocation(), diag::err_thread_thread_different_kind)
      << New->getDeclName() << (New->getTLSKind() == VarDecl::TLS_Dynamic);
    Diag(OldLocation, PrevDiag);
  }
}

// C++ doesn't have tentative definitions, so go right ahead and check here.
if (getLangOpts().CPlusPlus &&
    New->isThisDeclarationADefinition() == VarDecl::Definition) {
  if (Old->isStaticDataMember() && Old->getCanonicalDecl()->isInline() &&
      Old->getCanonicalDecl()->isConstexpr()) {
    // This definition won't be a definition any more once it's been merged.
    Diag(New->getLocation(),
         diag::warn_deprecated_redundant_constexpr_static_def);
  } else if (VarDecl *Def = Old->getDefinition()) {
    if (checkVarDeclRedefinition(Def, New))
      return;
  }
}

if (haveIncompatibleLanguageLinkages(Old, New)) {
  Diag(New->getLocation(), diag::err_different_language_linkage) << New;
  Diag(OldLocation, PrevDiag);
  New->setInvalidDecl();
  return;
}

// Merge "used" flag.
if (Old->getMostRecentDecl()->isUsed(false))
  New->setIsUsed();

// Keep a chain of previous declarations.
New->setPreviousDecl(Old);
if (NewTemplate)
  NewTemplate->setPreviousDecl(OldTemplate);

// Inherit access appropriately.
New->setAccess(Old->getAccess());
if (NewTemplate)
  NewTemplate->setAccess(New->getAccess());

if (Old->isInline())
  New->setImplicitlyInline();
4330}

4332void Sema::notePreviousDefinition(const NamedDecl *Old, SourceLocation New) {
SourceManager &SrcMgr = getSourceManager();
auto FNewDecLoc = SrcMgr.getDecomposedLoc(New);
auto FOldDecLoc = SrcMgr.getDecomposedLoc(Old->getLocation());
auto *FNew = SrcMgr.getFileEntryForID(FNewDecLoc.first);
auto *FOld = SrcMgr.getFileEntryForID(FOldDecLoc.first);
auto &HSI = PP.getHeaderSearchInfo();
StringRef HdrFilename =
    SrcMgr.getFilename(SrcMgr.getSpellingLoc(Old->getLocation()));

auto noteFromModuleOrInclude = [&](Module *Mod,
                                   SourceLocation IncLoc) -> bool {
  // Redefinition errors with modules are common with non modular mapped
  // headers, example: a non-modular header H in module A that also gets
  // included directly in a TU. Pointing twice to the same header/definition
  // is confusing, try to get better diagnostics when modules is on.
  if (IncLoc.isValid()) {
    if (Mod) {
      Diag(IncLoc, diag::note_redefinition_modules_same_file)
          << HdrFilename.str() << Mod->getFullModuleName();
      if (!Mod->DefinitionLoc.isInvalid())
        Diag(Mod->DefinitionLoc, diag::note_defined_here)
            << Mod->getFullModuleName();
    } else {
      Diag(IncLoc, diag::note_redefinition_include_same_file)
          << HdrFilename.str();
    }
    return true;
  }

  return false;
};

// Is it the same file and same offset? Provide more information on why
// this leads to a redefinition error.
if (FNew == FOld && FNewDecLoc.second == FOldDecLoc.second) {
  SourceLocation OldIncLoc = SrcMgr.getIncludeLoc(FOldDecLoc.first);
  SourceLocation NewIncLoc = SrcMgr.getIncludeLoc(FNewDecLoc.first);
  bool EmittedDiag =
      noteFromModuleOrInclude(Old->getOwningModule(), OldIncLoc);
  EmittedDiag |= noteFromModuleOrInclude(getCurrentModule(), NewIncLoc);

  // If the header has no guards, emit a note suggesting one.
  if (FOld && !HSI.isFileMultipleIncludeGuarded(FOld))
    Diag(Old->getLocation(), diag::note_use_ifdef_guards);

  if (EmittedDiag)
    return;
}

// Redefinition coming from different files or couldn't do better above.
if (Old->getLocation().isValid())
  Diag(Old->getLocation(), diag::note_previous_definition);
4385}

4387/// We've just determined that \p Old and \p New both appear to be definitions
4388/// of the same variable. Either diagnose or fix the problem.
4389bool Sema::checkVarDeclRedefinition(VarDecl *Old, VarDecl *New) {
if (!hasVisibleDefinition(Old) &&
    (New->getFormalLinkage() == InternalLinkage ||
     New->isInline() ||
     New->getDescribedVarTemplate() ||
     New->getNumTemplateParameterLists() ||
     New->getDeclContext()->isDependentContext())) {
  // The previous definition is hidden, and multiple definitions are
  // permitted (in separate TUs). Demote this to a declaration.
  New->demoteThisDefinitionToDeclaration();

  // Make the canonical definition visible.
  if (auto *OldTD = Old->getDescribedVarTemplate())
    makeMergedDefinitionVisible(OldTD);
  makeMergedDefinitionVisible(Old);
  return false;
} else {
  Diag(New->getLocation(), diag::err_redefinition) << New;
  notePreviousDefinition(Old, New->getLocation());
  New->setInvalidDecl();
  return true;
}
4411}

4413/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4414/// no declarator (e.g. "struct foo;") is parsed.
4415Decl *
4416Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                               RecordDecl *&AnonRecord) {
return ParsedFreeStandingDeclSpec(S, AS, DS, MultiTemplateParamsArg(), false,
                                  AnonRecord);
4420}

4422// The MS ABI changed between VS2013 and VS2015 with regard to numbers used to
4423// disambiguate entities defined in different scopes.
4424// While the VS2015 ABI fixes potential miscompiles, it is also breaks
4425// compatibility.
4426// We will pick our mangling number depending on which version of MSVC is being
4427// targeted.
4428static unsigned getMSManglingNumber(const LangOptions &LO, Scope *S) {
return LO.isCompatibleWithMSVC(LangOptions::MSVC2015)
           ? S->getMSCurManglingNumber()
           : S->getMSLastManglingNumber();
4432}

4434void Sema::handleTagNumbering(const TagDecl *Tag, Scope *TagScope) {
if (!Context.getLangOpts().CPlusPlus)
  return;

if (isa<CXXRecordDecl>(Tag->getParent())) {
  // If this tag is the direct child of a class, number it if
  // it is anonymous.
  if (!Tag->getName().empty() || Tag->getTypedefNameForAnonDecl())
    return;
  MangleNumberingContext &MCtx =
      Context.getManglingNumberContext(Tag->getParent());
  Context.setManglingNumber(
      Tag, MCtx.getManglingNumber(
               Tag, getMSManglingNumber(getLangOpts(), TagScope)));
  return;
}

// If this tag isn't a direct child of a class, number it if it is local.
MangleNumberingContext *MCtx;
Decl *ManglingContextDecl;
std::tie(MCtx, ManglingContextDecl) =
    getCurrentMangleNumberContext(Tag->getDeclContext());
if (MCtx) {
  Context.setManglingNumber(
      Tag, MCtx->getManglingNumber(
               Tag, getMSManglingNumber(getLangOpts(), TagScope)));
}
4461}

4463namespace {
4464struct NonCLikeKind {
enum {
  None,
  BaseClass,
  DefaultMemberInit,
  Lambda,
  Friend,
  OtherMember,
  Invalid,
} Kind = None;
SourceRange Range;

explicit operator bool() { return Kind != None; }
4477};
4478}

4480/// Determine whether a class is C-like, according to the rules of C++
4481/// [dcl.typedef] for anonymous classes with typedef names for linkage.
4482static NonCLikeKind getNonCLikeKindForAnonymousStruct(const CXXRecordDecl *RD) {
if (RD->isInvalidDecl())
  return {NonCLikeKind::Invalid, {}};

// C++ [dcl.typedef]p9: [P1766R1]
//   An unnamed class with a typedef name for linkage purposes shall not
//
//    -- have any base classes
if (RD->getNumBases())
  return {NonCLikeKind::BaseClass,
          SourceRange(RD->bases_begin()->getBeginLoc(),
                      RD->bases_end()[-1].getEndLoc())};
bool Invalid = false;
for (Decl *D : RD->decls()) {
  // Don't complain about things we already diagnosed.
  if (D->isInvalidDecl()) {
    Invalid = true;
    continue;
  }

  //  -- have any [...] default member initializers
  if (auto *FD = dyn_cast<FieldDecl>(D)) {
    if (FD->hasInClassInitializer()) {
      auto *Init = FD->getInClassInitializer();
      return {NonCLikeKind::DefaultMemberInit,
              Init ? Init->getSourceRange() : D->getSourceRange()};
    }
    continue;
  }

  // FIXME: We don't allow friend declarations. This violates the wording of
  // P1766, but not the intent.
  if (isa<FriendDecl>(D))
    return {NonCLikeKind::Friend, D->getSourceRange()};

  //  -- declare any members other than non-static data members, member
  //     enumerations, or member classes,
  if (isa<StaticAssertDecl>(D) || isa<IndirectFieldDecl>(D) ||
      isa<EnumDecl>(D))
    continue;
  auto *MemberRD = dyn_cast<CXXRecordDecl>(D);
  if (!MemberRD) {
    if (D->isImplicit())
      continue;
    return {NonCLikeKind::OtherMember, D->getSourceRange()};
  }

  //  -- contain a lambda-expression,
  if (MemberRD->isLambda())
    return {NonCLikeKind::Lambda, MemberRD->getSourceRange()};

  //  and all member classes shall also satisfy these requirements
  //  (recursively).
  if (MemberRD->isThisDeclarationADefinition()) {
    if (auto Kind = getNonCLikeKindForAnonymousStruct(MemberRD))
      return Kind;
  }
}

return {Invalid ? NonCLikeKind::Invalid : NonCLikeKind::None, {}};
4542}

4544void Sema::setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
                                      TypedefNameDecl *NewTD) {
if (TagFromDeclSpec->isInvalidDecl())
  return;

// Do nothing if the tag already has a name for linkage purposes.
if (TagFromDeclSpec->hasNameForLinkage())
  return;

// A well-formed anonymous tag must always be a TUK_Definition.
assert(TagFromDeclSpec->isThisDeclarationADefinition())((void)0);

// The type must match the tag exactly;  no qualifiers allowed.
if (!Context.hasSameType(NewTD->getUnderlyingType(),
                         Context.getTagDeclType(TagFromDeclSpec))) {
  if (getLangOpts().CPlusPlus)
    Context.addTypedefNameForUnnamedTagDecl(TagFromDeclSpec, NewTD);
  return;
}

// C++ [dcl.typedef]p9: [P1766R1, applied as DR]
//   An unnamed class with a typedef name for linkage purposes shall [be
//   C-like].
//
// FIXME: Also diagnose if we've already computed the linkage. That ideally
// shouldn't happen, but there are constructs that the language rule doesn't
// disallow for which we can't reasonably avoid computing linkage early.
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(TagFromDeclSpec);
NonCLikeKind NonCLike = RD ? getNonCLikeKindForAnonymousStruct(RD)
                           : NonCLikeKind();
bool ChangesLinkage = TagFromDeclSpec->hasLinkageBeenComputed();
if (NonCLike || ChangesLinkage) {
  if (NonCLike.Kind == NonCLikeKind::Invalid)
    return;

  unsigned DiagID = diag::ext_non_c_like_anon_struct_in_typedef;
  if (ChangesLinkage) {
    // If the linkage changes, we can't accept this as an extension.
    if (NonCLike.Kind == NonCLikeKind::None)
      DiagID = diag::err_typedef_changes_linkage;
    else
      DiagID = diag::err_non_c_like_anon_struct_in_typedef;
  }

  SourceLocation FixitLoc =
      getLocForEndOfToken(TagFromDeclSpec->getInnerLocStart());
  llvm::SmallString<40> TextToInsert;
  TextToInsert += ' ';
  TextToInsert += NewTD->getIdentifier()->getName();

  Diag(FixitLoc, DiagID)
    << isa<TypeAliasDecl>(NewTD)
    << FixItHint::CreateInsertion(FixitLoc, TextToInsert);
  if (NonCLike.Kind != NonCLikeKind::None) {
    Diag(NonCLike.Range.getBegin(), diag::note_non_c_like_anon_struct)
      << NonCLike.Kind - 1 << NonCLike.Range;
  }
  Diag(NewTD->getLocation(), diag::note_typedef_for_linkage_here)
    << NewTD << isa<TypeAliasDecl>(NewTD);

  if (ChangesLinkage)
    return;
}

// Otherwise, set this as the anon-decl typedef for the tag.
TagFromDeclSpec->setTypedefNameForAnonDecl(NewTD);
4610}

4612static unsigned GetDiagnosticTypeSpecifierID(DeclSpec::TST T) {
switch (T) {
case DeclSpec::TST_class:
  return 0;
case DeclSpec::TST_struct:
  return 1;
case DeclSpec::TST_interface:
  return 2;
case DeclSpec::TST_union:
  return 3;
case DeclSpec::TST_enum:
  return 4;
default:
  llvm_unreachable("unexpected type specifier")__builtin_unreachable();
}
4627}

4629/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4630/// no declarator (e.g. "struct foo;") is parsed. It also accepts template
4631/// parameters to cope with template friend declarations.
4632Decl *
4633Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
                               MultiTemplateParamsArg TemplateParams,
                               bool IsExplicitInstantiation,
                               RecordDecl *&AnonRecord) {
Decl *TagD = nullptr;
TagDecl *Tag = nullptr;
if (DS.getTypeSpecType() == DeclSpec::TST_class ||
    DS.getTypeSpecType() == DeclSpec::TST_struct ||
    DS.getTypeSpecType() == DeclSpec::TST_interface ||
    DS.getTypeSpecType() == DeclSpec::TST_union ||
    DS.getTypeSpecType() == DeclSpec::TST_enum) {
  TagD = DS.getRepAsDecl();

  if (!TagD) // We probably had an error
    return nullptr;

  // Note that the above type specs guarantee that the
  // type rep is a Decl, whereas in many of the others
  // it's a Type.
  if (isa<TagDecl>(TagD))
    Tag = cast<TagDecl>(TagD);
  else if (ClassTemplateDecl *CTD = dyn_cast<ClassTemplateDecl>(TagD))
    Tag = CTD->getTemplatedDecl();
}

if (Tag) {
  handleTagNumbering(Tag, S);
  Tag->setFreeStanding();
  if (Tag->isInvalidDecl())
    return Tag;
}

if (unsigned TypeQuals = DS.getTypeQualifiers()) {
  // Enforce C99 6.7.3p2: "Types other than pointer types derived from object
  // or incomplete types shall not be restrict-qualified."
  if (TypeQuals & DeclSpec::TQ_restrict)
    Diag(DS.getRestrictSpecLoc(),
         diag::err_typecheck_invalid_restrict_not_pointer_noarg)
         << DS.getSourceRange();
}

if (DS.isInlineSpecified())
  Diag(DS.getInlineSpecLoc(), diag::err_inline_non_function)
      << getLangOpts().CPlusPlus17;

if (DS.hasConstexprSpecifier()) {
  // C++0x [dcl.constexpr]p1: constexpr can only be applied to declarations
  // and definitions of functions and variables.
  // C++2a [dcl.constexpr]p1: The consteval specifier shall be applied only to
  // the declaration of a function or function template
  if (Tag)
    Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_tag)
        << GetDiagnosticTypeSpecifierID(DS.getTypeSpecType())
        << static_cast<int>(DS.getConstexprSpecifier());
  else
    Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_wrong_decl_kind)
        << static_cast<int>(DS.getConstexprSpecifier());
  // Don't emit warnings after this error.
  return TagD;
}

DiagnoseFunctionSpecifiers(DS);

if (DS.isFriendSpecified()) {
  // If we're dealing with a decl but not a TagDecl, assume that
  // whatever routines created it handled the friendship aspect.
  if (TagD && !Tag)
    return nullptr;
  return ActOnFriendTypeDecl(S, DS, TemplateParams);
}

const CXXScopeSpec &SS = DS.getTypeSpecScope();
bool IsExplicitSpecialization =
  !TemplateParams.empty() && TemplateParams.back()->size() == 0;
if (Tag && SS.isNotEmpty() && !Tag->isCompleteDefinition() &&
    !IsExplicitInstantiation && !IsExplicitSpecialization &&
    !isa<ClassTemplatePartialSpecializationDecl>(Tag)) {
  // Per C++ [dcl.type.elab]p1, a class declaration cannot have a
  // nested-name-specifier unless it is an explicit instantiation
  // or an explicit specialization.
  //
  // FIXME: We allow class template partial specializations here too, per the
  // obvious intent of DR1819.
  //
  // Per C++ [dcl.enum]p1, an opaque-enum-declaration can't either.
  Diag(SS.getBeginLoc(), diag::err_standalone_class_nested_name_specifier)
      << GetDiagnosticTypeSpecifierID(DS.getTypeSpecType()) << SS.getRange();
  return nullptr;
}

// Track whether this decl-specifier declares anything.
bool DeclaresAnything = true;

// Handle anonymous struct definitions.
if (RecordDecl *Record = dyn_cast_or_null<RecordDecl>(Tag)) {
  if (!Record->getDeclName() && Record->isCompleteDefinition() &&
      DS.getStorageClassSpec() != DeclSpec::SCS_typedef) {
    if (getLangOpts().CPlusPlus ||
        Record->getDeclContext()->isRecord()) {
      // If CurContext is a DeclContext that can contain statements,
      // RecursiveASTVisitor won't visit the decls that
      // BuildAnonymousStructOrUnion() will put into CurContext.
      // Also store them here so that they can be part of the
      // DeclStmt that gets created in this case.
      // FIXME: Also return the IndirectFieldDecls created by
      // BuildAnonymousStructOr union, for the same reason?
      if (CurContext->isFunctionOrMethod())
        AnonRecord = Record;
      return BuildAnonymousStructOrUnion(S, DS, AS, Record,
                                         Context.getPrintingPolicy());
    }

    DeclaresAnything = false;
  }
}

// C11 6.7.2.1p2:
//   A struct-declaration that does not declare an anonymous structure or
//   anonymous union shall contain a struct-declarator-list.
//
// This rule also existed in C89 and C99; the grammar for struct-declaration
// did not permit a struct-declaration without a struct-declarator-list.
if (!getLangOpts().CPlusPlus && CurContext->isRecord() &&
    DS.getStorageClassSpec() == DeclSpec::SCS_unspecified) {
  // Check for Microsoft C extension: anonymous struct/union member.
  // Handle 2 kinds of anonymous struct/union:
  //   struct STRUCT;
  //   union UNION;
  // and
  //   STRUCT_TYPE;  <- where STRUCT_TYPE is a typedef struct.
  //   UNION_TYPE;   <- where UNION_TYPE is a typedef union.
  if ((Tag && Tag->getDeclName()) ||
      DS.getTypeSpecType() == DeclSpec::TST_typename) {
    RecordDecl *Record = nullptr;
    if (Tag)
      Record = dyn_cast<RecordDecl>(Tag);
    else if (const RecordType *RT =
                 DS.getRepAsType().get()->getAsStructureType())
      Record = RT->getDecl();
    else if (const RecordType *UT = DS.getRepAsType().get()->getAsUnionType())
      Record = UT->getDecl();

    if (Record && getLangOpts().MicrosoftExt) {
      Diag(DS.getBeginLoc(), diag::ext_ms_anonymous_record)
          << Record->isUnion() << DS.getSourceRange();
      return BuildMicrosoftCAnonymousStruct(S, DS, Record);
    }

    DeclaresAnything = false;
  }
}

// Skip all the checks below if we have a type error.
if (DS.getTypeSpecType() == DeclSpec::TST_error ||
    (TagD && TagD->isInvalidDecl()))
  return TagD;

if (getLangOpts().CPlusPlus &&
    DS.getStorageClassSpec() != DeclSpec::SCS_typedef)
  if (EnumDecl *Enum = dyn_cast_or_null<EnumDecl>(Tag))
    if (Enum->enumerator_begin() == Enum->enumerator_end() &&
        !Enum->getIdentifier() && !Enum->isInvalidDecl())
      DeclaresAnything = false;

if (!DS.isMissingDeclaratorOk()) {
  // Customize diagnostic for a typedef missing a name.
  if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef)
    Diag(DS.getBeginLoc(), diag::ext_typedef_without_a_name)
        << DS.getSourceRange();
  else
    DeclaresAnything = false;
}

if (DS.isModulePrivateSpecified() &&
    Tag && Tag->getDeclContext()->isFunctionOrMethod())
  Diag(DS.getModulePrivateSpecLoc(), diag::err_module_private_local_class)
    << Tag->getTagKind()
    << FixItHint::CreateRemoval(DS.getModulePrivateSpecLoc());

ActOnDocumentableDecl(TagD);

// C 6.7/2:
//   A declaration [...] shall declare at least a declarator [...], a tag,
//   or the members of an enumeration.
// C++ [dcl.dcl]p3:
//   [If there are no declarators], and except for the declaration of an
//   unnamed bit-field, the decl-specifier-seq shall introduce one or more
//   names into the program, or shall redeclare a name introduced by a
//   previous declaration.
if (!DeclaresAnything) {
  // In C, we allow this as a (popular) extension / bug. Don't bother
  // producing further diagnostics for redundant qualifiers after this.
  Diag(DS.getBeginLoc(), (IsExplicitInstantiation || !TemplateParams.empty())
                             ? diag::err_no_declarators
                             : diag::ext_no_declarators)
      << DS.getSourceRange();
  return TagD;
}

// C++ [dcl.stc]p1:
//   If a storage-class-specifier appears in a decl-specifier-seq, [...] the
//   init-declarator-list of the declaration shall not be empty.
// C++ [dcl.fct.spec]p1:
//   If a cv-qualifier appears in a decl-specifier-seq, the
//   init-declarator-list of the declaration shall not be empty.
//
// Spurious qualifiers here appear to be valid in C.
unsigned DiagID = diag::warn_standalone_specifier;
if (getLangOpts().CPlusPlus)
  DiagID = diag::ext_standalone_specifier;

// Note that a linkage-specification sets a storage class, but
// 'extern "C" struct foo;' is actually valid and not theoretically
// useless.
if (DeclSpec::SCS SCS = DS.getStorageClassSpec()) {
  if (SCS == DeclSpec::SCS_mutable)
    // Since mutable is not a viable storage class specifier in C, there is
    // no reason to treat it as an extension. Instead, diagnose as an error.
    Diag(DS.getStorageClassSpecLoc(), diag::err_mutable_nonmember);
  else if (!DS.isExternInLinkageSpec() && SCS != DeclSpec::SCS_typedef)
    Diag(DS.getStorageClassSpecLoc(), DiagID)
      << DeclSpec::getSpecifierName(SCS);
}

if (DeclSpec::TSCS TSCS = DS.getThreadStorageClassSpec())
  Diag(DS.getThreadStorageClassSpecLoc(), DiagID)
    << DeclSpec::getSpecifierName(TSCS);
if (DS.getTypeQualifiers()) {
  if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
    Diag(DS.getConstSpecLoc(), DiagID) << "const";
  if (DS.getTypeQualifiers() & DeclSpec::TQ_volatile)
    Diag(DS.getConstSpecLoc(), DiagID) << "volatile";
  // Restrict is covered above.
  if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
    Diag(DS.getAtomicSpecLoc(), DiagID) << "_Atomic";
  if (DS.getTypeQualifiers() & DeclSpec::TQ_unaligned)
    Diag(DS.getUnalignedSpecLoc(), DiagID) << "__unaligned";
}

// Warn about ignored type attributes, for example:
// __attribute__((aligned)) struct A;
// Attributes should be placed after tag to apply to type declaration.
if (!DS.getAttributes().empty()) {
  DeclSpec::TST TypeSpecType = DS.getTypeSpecType();
  if (TypeSpecType == DeclSpec::TST_class ||
      TypeSpecType == DeclSpec::TST_struct ||
      TypeSpecType == DeclSpec::TST_interface ||
      TypeSpecType == DeclSpec::TST_union ||
      TypeSpecType == DeclSpec::TST_enum) {
    for (const ParsedAttr &AL : DS.getAttributes())
      Diag(AL.getLoc(), diag::warn_declspec_attribute_ignored)
          << AL << GetDiagnosticTypeSpecifierID(TypeSpecType);
  }
}

return TagD;
4889}

4891/// We are trying to inject an anonymous member into the given scope;
4892/// check if there's an existing declaration that can't be overloaded.
4893///
4894/// \return true if this is a forbidden redeclaration
4895static bool CheckAnonMemberRedeclaration(Sema &SemaRef,
                                       Scope *S,
                                       DeclContext *Owner,
                                       DeclarationName Name,
                                       SourceLocation NameLoc,
                                       bool IsUnion) {
LookupResult R(SemaRef, Name, NameLoc, Sema::LookupMemberName,
               Sema::ForVisibleRedeclaration);
if (!SemaRef.LookupName(R, S)) return false;

// Pick a representative declaration.
NamedDecl *PrevDecl = R.getRepresentativeDecl()->getUnderlyingDecl();
assert(PrevDecl && "Expected a non-null Decl")((void)0);

if (!SemaRef.isDeclInScope(PrevDecl, Owner, S))
  return false;

SemaRef.Diag(NameLoc, diag::err_anonymous_record_member_redecl)
  << IsUnion << Name;
SemaRef.Diag(PrevDecl->getLocation(), diag::note_previous_declaration);

return true;
4917}

4919/// InjectAnonymousStructOrUnionMembers - Inject the members of the
4920/// anonymous struct or union AnonRecord into the owning context Owner
4921/// and scope S. This routine will be invoked just after we realize
4922/// that an unnamed union or struct is actually an anonymous union or
4923/// struct, e.g.,
4924///
4925/// @code
4926/// union {
4927///   int i;
4928///   float f;
4929/// }; // InjectAnonymousStructOrUnionMembers called here to inject i and
4930///    // f into the surrounding scope.x
4931/// @endcode
4932///
4933/// This routine is recursive, injecting the names of nested anonymous
4934/// structs/unions into the owning context and scope as well.
4935static bool
4936InjectAnonymousStructOrUnionMembers(Sema &SemaRef, Scope *S, DeclContext *Owner,
                                  RecordDecl *AnonRecord, AccessSpecifier AS,
                                  SmallVectorImpl<NamedDecl *> &Chaining) {
bool Invalid = false;

// Look every FieldDecl and IndirectFieldDecl with a name.
for (auto *D : AnonRecord->decls()) {
  if ((isa<FieldDecl>(D) || isa<IndirectFieldDecl>(D)) &&
      cast<NamedDecl>(D)->getDeclName()) {
    ValueDecl *VD = cast<ValueDecl>(D);
    if (CheckAnonMemberRedeclaration(SemaRef, S, Owner, VD->getDeclName(),
                                     VD->getLocation(),
                                     AnonRecord->isUnion())) {
      // C++ [class.union]p2:
      //   The names of the members of an anonymous union shall be
      //   distinct from the names of any other entity in the
      //   scope in which the anonymous union is declared.
      Invalid = true;
    } else {
      // C++ [class.union]p2:
      //   For the purpose of name lookup, after the anonymous union
      //   definition, the members of the anonymous union are
      //   considered to have been defined in the scope in which the
      //   anonymous union is declared.
      unsigned OldChainingSize = Chaining.size();
      if (IndirectFieldDecl *IF = dyn_cast<IndirectFieldDecl>(VD))
        Chaining.append(IF->chain_begin(), IF->chain_end());
      else
        Chaining.push_back(VD);

      assert(Chaining.size() >= 2)((void)0);
      NamedDecl **NamedChain =
        new (SemaRef.Context)NamedDecl*[Chaining.size()];
      for (unsigned i = 0; i < Chaining.size(); i++)
        NamedChain[i] = Chaining[i];

      IndirectFieldDecl *IndirectField = IndirectFieldDecl::Create(
          SemaRef.Context, Owner, VD->getLocation(), VD->getIdentifier(),
          VD->getType(), {NamedChain, Chaining.size()});

      for (const auto *Attr : VD->attrs())
        IndirectField->addAttr(Attr->clone(SemaRef.Context));

      IndirectField->setAccess(AS);
      IndirectField->setImplicit();
      SemaRef.PushOnScopeChains(IndirectField, S);

      // That includes picking up the appropriate access specifier.
      if (AS != AS_none) IndirectField->setAccess(AS);

      Chaining.resize(OldChainingSize);
    }
  }
}

return Invalid;
4992}

4994/// StorageClassSpecToVarDeclStorageClass - Maps a DeclSpec::SCS to
4995/// a VarDecl::StorageClass. Any error reporting is up to the caller:
4996/// illegal input values are mapped to SC_None.
4997static StorageClass
4998StorageClassSpecToVarDeclStorageClass(const DeclSpec &DS) {
DeclSpec::SCS StorageClassSpec = DS.getStorageClassSpec();
assert(StorageClassSpec != DeclSpec::SCS_typedef &&((void)0)
       "Parser allowed 'typedef' as storage class VarDecl.")((void)0);
switch (StorageClassSpec) {
case DeclSpec::SCS_unspecified:    return SC_None;
case DeclSpec::SCS_extern:
  if (DS.isExternInLinkageSpec())
    return SC_None;
  return SC_Extern;
case DeclSpec::SCS_static:         return SC_Static;
case DeclSpec::SCS_auto:           return SC_Auto;
case DeclSpec::SCS_register:       return SC_Register;
case DeclSpec::SCS_private_extern: return SC_PrivateExtern;
  // Illegal SCSs map to None: error reporting is up to the caller.
case DeclSpec::SCS_mutable:        // Fall through.
case DeclSpec::SCS_typedef:        return SC_None;
}
llvm_unreachable("unknown storage class specifier")__builtin_unreachable();
5017}

5019static SourceLocation findDefaultInitializer(const CXXRecordDecl *Record) {
assert(Record->hasInClassInitializer())((void)0);

for (const auto *I : Record->decls()) {
  const auto *FD = dyn_cast<FieldDecl>(I);
  if (const auto *IFD = dyn_cast<IndirectFieldDecl>(I))
    FD = IFD->getAnonField();
  if (FD && FD->hasInClassInitializer())
    return FD->getLocation();
}

llvm_unreachable("couldn't find in-class initializer")__builtin_unreachable();
5031}

5033static void checkDuplicateDefaultInit(Sema &S, CXXRecordDecl *Parent,
                                    SourceLocation DefaultInitLoc) {
if (!Parent->isUnion() || !Parent->hasInClassInitializer())
  return;

S.Diag(DefaultInitLoc, diag::err_multiple_mem_union_initialization);
S.Diag(findDefaultInitializer(Parent), diag::note_previous_initializer) << 0;
5040}

5042static void checkDuplicateDefaultInit(Sema &S, CXXRecordDecl *Parent,
                                    CXXRecordDecl *AnonUnion) {
if (!Parent->isUnion() || !Parent->hasInClassInitializer())
  return;

checkDuplicateDefaultInit(S, Parent, findDefaultInitializer(AnonUnion));
5048}

5050/// BuildAnonymousStructOrUnion - Handle the declaration of an
5051/// anonymous structure or union. Anonymous unions are a C++ feature
5052/// (C++ [class.union]) and a C11 feature; anonymous structures
5053/// are a C11 feature and GNU C++ extension.
5054Decl *Sema::BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
                                      AccessSpecifier AS,
                                      RecordDecl *Record,
                                      const PrintingPolicy &Policy) {
DeclContext *Owner = Record->getDeclContext();

// Diagnose whether this anonymous struct/union is an extension.
if (Record->isUnion() && !getLangOpts().CPlusPlus && !getLangOpts().C11)
  Diag(Record->getLocation(), diag::ext_anonymous_union);
else if (!Record->isUnion() && getLangOpts().CPlusPlus)
  Diag(Record->getLocation(), diag::ext_gnu_anonymous_struct);
else if (!Record->isUnion() && !getLangOpts().C11)
  Diag(Record->getLocation(), diag::ext_c11_anonymous_struct);

// C and C++ require different kinds of checks for anonymous
// structs/unions.
bool Invalid = false;
if (getLangOpts().CPlusPlus) {
  const char *PrevSpec = nullptr;
  if (Record->isUnion()) {
    // C++ [class.union]p6:
    // C++17 [class.union.anon]p2:
    //   Anonymous unions declared in a named namespace or in the
    //   global namespace shall be declared static.
    unsigned DiagID;
    DeclContext *OwnerScope = Owner->getRedeclContext();
    if (DS.getStorageClassSpec() != DeclSpec::SCS_static &&
        (OwnerScope->isTranslationUnit() ||
         (OwnerScope->isNamespace() &&
          !cast<NamespaceDecl>(OwnerScope)->isAnonymousNamespace()))) {
      Diag(Record->getLocation(), diag::err_anonymous_union_not_static)
        << FixItHint::CreateInsertion(Record->getLocation(), "static ");

      // Recover by adding 'static'.
      DS.SetStorageClassSpec(*this, DeclSpec::SCS_static, SourceLocation(),
                             PrevSpec, DiagID, Policy);
    }
    // C++ [class.union]p6:
    //   A storage class is not allowed in a declaration of an
    //   anonymous union in a class scope.
    else if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified &&
             isa<RecordDecl>(Owner)) {
      Diag(DS.getStorageClassSpecLoc(),
           diag::err_anonymous_union_with_storage_spec)
        << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());

      // Recover by removing the storage specifier.
      DS.SetStorageClassSpec(*this, DeclSpec::SCS_unspecified,
                             SourceLocation(),
                             PrevSpec, DiagID, Context.getPrintingPolicy());
    }
  }

  // Ignore const/volatile/restrict qualifiers.
  if (DS.getTypeQualifiers()) {
    if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
      Diag(DS.getConstSpecLoc(), diag::ext_anonymous_struct_union_qualified)
        << Record->isUnion() << "const"
        << FixItHint::CreateRemoval(DS.getConstSpecLoc());
    if (DS.getTypeQualifiers() & DeclSpec::TQ_volatile)
      Diag(DS.getVolatileSpecLoc(),
           diag::ext_anonymous_struct_union_qualified)
        << Record->isUnion() << "volatile"
        << FixItHint::CreateRemoval(DS.getVolatileSpecLoc());
    if (DS.getTypeQualifiers() & DeclSpec::TQ_restrict)
      Diag(DS.getRestrictSpecLoc(),
           diag::ext_anonymous_struct_union_qualified)
        << Record->isUnion() << "restrict"
        << FixItHint::CreateRemoval(DS.getRestrictSpecLoc());
    if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
      Diag(DS.getAtomicSpecLoc(),
           diag::ext_anonymous_struct_union_qualified)
        << Record->isUnion() << "_Atomic"
        << FixItHint::CreateRemoval(DS.getAtomicSpecLoc());
    if (DS.getTypeQualifiers() & DeclSpec::TQ_unaligned)
      Diag(DS.getUnalignedSpecLoc(),
           diag::ext_anonymous_struct_union_qualified)
        << Record->isUnion() << "__unaligned"
        << FixItHint::CreateRemoval(DS.getUnalignedSpecLoc());

    DS.ClearTypeQualifiers();
  }

  // C++ [class.union]p2:
  //   The member-specification of an anonymous union shall only
  //   define non-static data members. [Note: nested types and
  //   functions cannot be declared within an anonymous union. ]
  for (auto *Mem : Record->decls()) {
    // Ignore invalid declarations; we already diagnosed them.
    if (Mem->isInvalidDecl())
      continue;

    if (auto *FD = dyn_cast<FieldDecl>(Mem)) {
      // C++ [class.union]p3:
      //   An anonymous union shall not have private or protected
      //   members (clause 11).
      assert(FD->getAccess() != AS_none)((void)0);
      if (FD->getAccess() != AS_public) {
        Diag(FD->getLocation(), diag::err_anonymous_record_nonpublic_member)
          << Record->isUnion() << (FD->getAccess() == AS_protected);
        Invalid = true;
      }

      // C++ [class.union]p1
      //   An object of a class with a non-trivial constructor, a non-trivial
      //   copy constructor, a non-trivial destructor, or a non-trivial copy
      //   assignment operator cannot be a member of a union, nor can an
      //   array of such objects.
      if (CheckNontrivialField(FD))
        Invalid = true;
    } else if (Mem->isImplicit()) {
      // Any implicit members are fine.
    } else if (isa<TagDecl>(Mem) && Mem->getDeclContext() != Record) {
      // This is a type that showed up in an
      // elaborated-type-specifier inside the anonymous struct or
      // union, but which actually declares a type outside of the
      // anonymous struct or union. It's okay.
    } else if (auto *MemRecord = dyn_cast<RecordDecl>(Mem)) {
      if (!MemRecord->isAnonymousStructOrUnion() &&
          MemRecord->getDeclName()) {
        // Visual C++ allows type definition in anonymous struct or union.
        if (getLangOpts().MicrosoftExt)
          Diag(MemRecord->getLocation(), diag::ext_anonymous_record_with_type)
            << Record->isUnion();
        else {
          // This is a nested type declaration.
          Diag(MemRecord->getLocation(), diag::err_anonymous_record_with_type)
            << Record->isUnion();
          Invalid = true;
        }
      } else {
        // This is an anonymous type definition within another anonymous type.
        // This is a popular extension, provided by Plan9, MSVC and GCC, but
        // not part of standard C++.
        Diag(MemRecord->getLocation(),
             diag::ext_anonymous_record_with_anonymous_type)
          << Record->isUnion();
      }
    } else if (isa<AccessSpecDecl>(Mem)) {
      // Any access specifier is fine.
    } else if (isa<StaticAssertDecl>(Mem)) {
      // In C++1z, static_assert declarations are also fine.
    } else {
      // We have something that isn't a non-static data
      // member. Complain about it.
      unsigned DK = diag::err_anonymous_record_bad_member;
      if (isa<TypeDecl>(Mem))
        DK = diag::err_anonymous_record_with_type;
      else if (isa<FunctionDecl>(Mem))
        DK = diag::err_anonymous_record_with_function;
      else if (isa<VarDecl>(Mem))
        DK = diag::err_anonymous_record_with_static;

      // Visual C++ allows type definition in anonymous struct or union.
      if (getLangOpts().MicrosoftExt &&
          DK == diag::err_anonymous_record_with_type)
        Diag(Mem->getLocation(), diag::ext_anonymous_record_with_type)
          << Record->isUnion();
      else {
        Diag(Mem->getLocation(), DK) << Record->isUnion();
        Invalid = true;
      }
    }
  }

  // C++11 [class.union]p8 (DR1460):
  //   At most one variant member of a union may have a
  //   brace-or-equal-initializer.
  if (cast<CXXRecordDecl>(Record)->hasInClassInitializer() &&
      Owner->isRecord())
    checkDuplicateDefaultInit(*this, cast<CXXRecordDecl>(Owner),
                              cast<CXXRecordDecl>(Record));
}

if (!Record->isUnion() && !Owner->isRecord()) {
  Diag(Record->getLocation(), diag::err_anonymous_struct_not_member)
    << getLangOpts().CPlusPlus;
  Invalid = true;
}

// C++ [dcl.dcl]p3:
//   [If there are no declarators], and except for the declaration of an
//   unnamed bit-field, the decl-specifier-seq shall introduce one or more
//   names into the program
// C++ [class.mem]p2:
//   each such member-declaration shall either declare at least one member
//   name of the class or declare at least one unnamed bit-field
//
// For C this is an error even for a named struct, and is diagnosed elsewhere.
if (getLangOpts().CPlusPlus && Record->field_empty())
  Diag(DS.getBeginLoc(), diag::ext_no_declarators) << DS.getSourceRange();

// Mock up a declarator.
Declarator Dc(DS, DeclaratorContext::Member);
TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
assert(TInfo && "couldn't build declarator info for anonymous struct/union")((void)0);

// Create a declaration for this anonymous struct/union.
NamedDecl *Anon = nullptr;
if (RecordDecl *OwningClass = dyn_cast<RecordDecl>(Owner)) {
  Anon = FieldDecl::Create(
      Context, OwningClass, DS.getBeginLoc(), Record->getLocation(),
      /*IdentifierInfo=*/nullptr, Context.getTypeDeclType(Record), TInfo,
      /*BitWidth=*/nullptr, /*Mutable=*/false,
      /*InitStyle=*/ICIS_NoInit);
  Anon->setAccess(AS);
  ProcessDeclAttributes(S, Anon, Dc);

  if (getLangOpts().CPlusPlus)
    FieldCollector->Add(cast<FieldDecl>(Anon));
} else {
  DeclSpec::SCS SCSpec = DS.getStorageClassSpec();
  StorageClass SC = StorageClassSpecToVarDeclStorageClass(DS);
  if (SCSpec == DeclSpec::SCS_mutable) {
    // mutable can only appear on non-static class members, so it's always
    // an error here
    Diag(Record->getLocation(), diag::err_mutable_nonmember);
    Invalid = true;
    SC = SC_None;
  }

  assert(DS.getAttributes().empty() && "No attribute expected")((void)0);
  Anon = VarDecl::Create(Context, Owner, DS.getBeginLoc(),
                         Record->getLocation(), /*IdentifierInfo=*/nullptr,
                         Context.getTypeDeclType(Record), TInfo, SC);

  // Default-initialize the implicit variable. This initialization will be
  // trivial in almost all cases, except if a union member has an in-class
  // initializer:
  //   union { int n = 0; };
  if (!Invalid)
    ActOnUninitializedDecl(Anon);
}
Anon->setImplicit();

// Mark this as an anonymous struct/union type.
Record->setAnonymousStructOrUnion(true);

// Add the anonymous struct/union object to the current
// context. We'll be referencing this object when we refer to one of
// its members.
Owner->addDecl(Anon);

// Inject the members of the anonymous struct/union into the owning
// context and into the identifier resolver chain for name lookup
// purposes.
SmallVector<NamedDecl*, 2> Chain;
Chain.push_back(Anon);

if (InjectAnonymousStructOrUnionMembers(*this, S, Owner, Record, AS, Chain))
  Invalid = true;

if (VarDecl *NewVD = dyn_cast<VarDecl>(Anon)) {
  if (getLangOpts().CPlusPlus && NewVD->isStaticLocal()) {
    MangleNumberingContext *MCtx;
    Decl *ManglingContextDecl;
    std::tie(MCtx, ManglingContextDecl) =
        getCurrentMangleNumberContext(NewVD->getDeclContext());
    if (MCtx) {
      Context.setManglingNumber(
          NewVD, MCtx->getManglingNumber(
                     NewVD, getMSManglingNumber(getLangOpts(), S)));
      Context.setStaticLocalNumber(NewVD, MCtx->getStaticLocalNumber(NewVD));
    }
  }
}

if (Invalid)
  Anon->setInvalidDecl();

return Anon;
5325}

5327/// BuildMicrosoftCAnonymousStruct - Handle the declaration of an
5328/// Microsoft C anonymous structure.
5329/// Ref: http://msdn.microsoft.com/en-us/library/z2cx9y4f.aspx
5330/// Example:
5331///
5332/// struct A { int a; };
5333/// struct B { struct A; int b; };
5334///
5335/// void foo() {
5336///   B var;
5337///   var.a = 3;
5338/// }
5339///
5340Decl *Sema::BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
                                         RecordDecl *Record) {
assert(Record && "expected a record!")((void)0);

// Mock up a declarator.
Declarator Dc(DS, DeclaratorContext::TypeName);
TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
assert(TInfo && "couldn't build declarator info for anonymous struct")((void)0);

auto *ParentDecl = cast<RecordDecl>(CurContext);
QualType RecTy = Context.getTypeDeclType(Record);

// Create a declaration for this anonymous struct.
NamedDecl *Anon =
    FieldDecl::Create(Context, ParentDecl, DS.getBeginLoc(), DS.getBeginLoc(),
                      /*IdentifierInfo=*/nullptr, RecTy, TInfo,
                      /*BitWidth=*/nullptr, /*Mutable=*/false,
                      /*InitStyle=*/ICIS_NoInit);
Anon->setImplicit();

// Add the anonymous struct object to the current context.
CurContext->addDecl(Anon);

// Inject the members of the anonymous struct into the current
// context and into the identifier resolver chain for name lookup
// purposes.
SmallVector<NamedDecl*, 2> Chain;
Chain.push_back(Anon);

RecordDecl *RecordDef = Record->getDefinition();
if (RequireCompleteSizedType(Anon->getLocation(), RecTy,
                             diag::err_field_incomplete_or_sizeless) ||
    InjectAnonymousStructOrUnionMembers(*this, S, CurContext, RecordDef,
                                        AS_none, Chain)) {
  Anon->setInvalidDecl();
  ParentDecl->setInvalidDecl();
}

return Anon;
5379}

5381/// GetNameForDeclarator - Determine the full declaration name for the
5382/// given Declarator.
5383DeclarationNameInfo Sema::GetNameForDeclarator(Declarator &D) {
return GetNameFromUnqualifiedId(D.getName());
5385}

5387/// Retrieves the declaration name from a parsed unqualified-id.
5388DeclarationNameInfo
5389Sema::GetNameFromUnqualifiedId(const UnqualifiedId &Name) {
DeclarationNameInfo NameInfo;
NameInfo.setLoc(Name.StartLocation);

switch (Name.getKind()) {

case UnqualifiedIdKind::IK_ImplicitSelfParam:
case UnqualifiedIdKind::IK_Identifier:
  NameInfo.setName(Name.Identifier);
  return NameInfo;

case UnqualifiedIdKind::IK_DeductionGuideName: {
  // C++ [temp.deduct.guide]p3:
  //   The simple-template-id shall name a class template specialization.
  //   The template-name shall be the same identifier as the template-name
  //   of the simple-template-id.
  // These together intend to imply that the template-name shall name a
  // class template.
  // FIXME: template<typename T> struct X {};
  //        template<typename T> using Y = X<T>;
  //        Y(int) -> Y<int>;
  //   satisfies these rules but does not name a class template.
  TemplateName TN = Name.TemplateName.get().get();
  auto *Template = TN.getAsTemplateDecl();
  if (!Template || !isa<ClassTemplateDecl>(Template)) {
    Diag(Name.StartLocation,
         diag::err_deduction_guide_name_not_class_template)
      << (int)getTemplateNameKindForDiagnostics(TN) << TN;
    if (Template)
      Diag(Template->getLocation(), diag::note_template_decl_here);
    return DeclarationNameInfo();
  }

  NameInfo.setName(
      Context.DeclarationNames.getCXXDeductionGuideName(Template));
  return NameInfo;
}

case UnqualifiedIdKind::IK_OperatorFunctionId:
  NameInfo.setName(Context.DeclarationNames.getCXXOperatorName(
                                         Name.OperatorFunctionId.Operator));
  NameInfo.setCXXOperatorNameRange(SourceRange(
      Name.OperatorFunctionId.SymbolLocations[0], Name.EndLocation));
  return NameInfo;

case UnqualifiedIdKind::IK_LiteralOperatorId:
  NameInfo.setName(Context.DeclarationNames.getCXXLiteralOperatorName(
                                                         Name.Identifier));
  NameInfo.setCXXLiteralOperatorNameLoc(Name.EndLocation);
  return NameInfo;

case UnqualifiedIdKind::IK_ConversionFunctionId: {
  TypeSourceInfo *TInfo;
  QualType Ty = GetTypeFromParser(Name.ConversionFunctionId, &TInfo);
  if (Ty.isNull())
    return DeclarationNameInfo();
  NameInfo.setName(Context.DeclarationNames.getCXXConversionFunctionName(
                                             Context.getCanonicalType(Ty)));
  NameInfo.setNamedTypeInfo(TInfo);
  return NameInfo;
}

case UnqualifiedIdKind::IK_ConstructorName: {
  TypeSourceInfo *TInfo;
  QualType Ty = GetTypeFromParser(Name.ConstructorName, &TInfo);
  if (Ty.isNull())
    return DeclarationNameInfo();
  NameInfo.setName(Context.DeclarationNames.getCXXConstructorName(
                                            Context.getCanonicalType(Ty)));
  NameInfo.setNamedTypeInfo(TInfo);
  return NameInfo;
}

case UnqualifiedIdKind::IK_ConstructorTemplateId: {
  // In well-formed code, we can only have a constructor
  // template-id that refers to the current context, so go there
  // to find the actual type being constructed.
  CXXRecordDecl *CurClass = dyn_cast<CXXRecordDecl>(CurContext);
  if (!CurClass || CurClass->getIdentifier() != Name.TemplateId->Name)
    return DeclarationNameInfo();

  // Determine the type of the class being constructed.
  QualType CurClassType = Context.getTypeDeclType(CurClass);

  // FIXME: Check two things: that the template-id names the same type as
  // CurClassType, and that the template-id does not occur when the name
  // was qualified.

  NameInfo.setName(Context.DeclarationNames.getCXXConstructorName(
                                  Context.getCanonicalType(CurClassType)));
  // FIXME: should we retrieve TypeSourceInfo?
  NameInfo.setNamedTypeInfo(nullptr);
  return NameInfo;
}

case UnqualifiedIdKind::IK_DestructorName: {
  TypeSourceInfo *TInfo;
  QualType Ty = GetTypeFromParser(Name.DestructorName, &TInfo);
  if (Ty.isNull())
    return DeclarationNameInfo();
  NameInfo.setName(Context.DeclarationNames.getCXXDestructorName(
                                            Context.getCanonicalType(Ty)));
  NameInfo.setNamedTypeInfo(TInfo);
  return NameInfo;
}

case UnqualifiedIdKind::IK_TemplateId: {
  TemplateName TName = Name.TemplateId->Template.get();
  SourceLocation TNameLoc = Name.TemplateId->TemplateNameLoc;
  return Context.getNameForTemplate(TName, TNameLoc);
}

} // switch (Name.getKind())

llvm_unreachable("Unknown name kind")__builtin_unreachable();
5504}

5506static QualType getCoreType(QualType Ty) {
do {
  if (Ty->isPointerType() || Ty->isReferenceType())
    Ty = Ty->getPointeeType();
  else if (Ty->isArrayType())
    Ty = Ty->castAsArrayTypeUnsafe()->getElementType();
  else
    return Ty.withoutLocalFastQualifiers();
} while (true);
5515}

5517/// hasSimilarParameters - Determine whether the C++ functions Declaration
5518/// and Definition have "nearly" matching parameters. This heuristic is
5519/// used to improve diagnostics in the case where an out-of-line function
5520/// definition doesn't match any declaration within the class or namespace.
5521/// Also sets Params to the list of indices to the parameters that differ
5522/// between the declaration and the definition. If hasSimilarParameters
5523/// returns true and Params is empty, then all of the parameters match.
5524static bool hasSimilarParameters(ASTContext &Context,
                                   FunctionDecl *Declaration,
                                   FunctionDecl *Definition,
                                   SmallVectorImpl<unsigned> &Params) {
Params.clear();
if (Declaration->param_size() != Definition->param_size())
  return false;
for (unsigned Idx = 0; Idx < Declaration->param_size(); ++Idx) {
  QualType DeclParamTy = Declaration->getParamDecl(Idx)->getType();
  QualType DefParamTy = Definition->getParamDecl(Idx)->getType();

  // The parameter types are identical
  if (Context.hasSameUnqualifiedType(DefParamTy, DeclParamTy))
    continue;

  QualType DeclParamBaseTy = getCoreType(DeclParamTy);
  QualType DefParamBaseTy = getCoreType(DefParamTy);
  const IdentifierInfo *DeclTyName = DeclParamBaseTy.getBaseTypeIdentifier();
  const IdentifierInfo *DefTyName = DefParamBaseTy.getBaseTypeIdentifier();

  if (Context.hasSameUnqualifiedType(DeclParamBaseTy, DefParamBaseTy) ||
      (DeclTyName && DeclTyName == DefTyName))
    Params.push_back(Idx);
  else  // The two parameters aren't even close
    return false;
}

return true;
5552}

5554/// NeedsRebuildingInCurrentInstantiation - Checks whether the given
5555/// declarator needs to be rebuilt in the current instantiation.
5556/// Any bits of declarator which appear before the name are valid for
5557/// consideration here.  That's specifically the type in the decl spec
5558/// and the base type in any member-pointer chunks.
5559static bool RebuildDeclaratorInCurrentInstantiation(Sema &S, Declarator &D,
                                                  DeclarationName Name) {
// The types we specifically need to rebuild are:
//   - typenames, typeofs, and decltypes
//   - types which will become injected class names
// Of course, we also need to rebuild any type referencing such a
// type.  It's safest to just say "dependent", but we call out a
// few cases here.

DeclSpec &DS = D.getMutableDeclSpec();
switch (DS.getTypeSpecType()) {
case DeclSpec::TST_typename:
case DeclSpec::TST_typeofType:
case DeclSpec::TST_underlyingType:
case DeclSpec::TST_atomic: {
  // Grab the type from the parser.
  TypeSourceInfo *TSI = nullptr;
  QualType T = S.GetTypeFromParser(DS.getRepAsType(), &TSI);
  if (T.isNull() || !T->isInstantiationDependentType()) break;

  // Make sure there's a type source info.  This isn't really much
  // of a waste; most dependent types should have type source info
  // attached already.
  if (!TSI)
    TSI = S.Context.getTrivialTypeSourceInfo(T, DS.getTypeSpecTypeLoc());

  // Rebuild the type in the current instantiation.
  TSI = S.RebuildTypeInCurrentInstantiation(TSI, D.getIdentifierLoc(), Name);
  if (!TSI) return true;

  // Store the new type back in the decl spec.
  ParsedType LocType = S.CreateParsedType(TSI->getType(), TSI);
  DS.UpdateTypeRep(LocType);
  break;
}

case DeclSpec::TST_decltype:
case DeclSpec::TST_typeofExpr: {
  Expr *E = DS.getRepAsExpr();
  ExprResult Result = S.RebuildExprInCurrentInstantiation(E);
  if (Result.isInvalid()) return true;
  DS.UpdateExprRep(Result.get());
  break;
}

default:
  // Nothing to do for these decl specs.
  break;
}

// It doesn't matter what order we do this in.
for (unsigned I = 0, E = D.getNumTypeObjects(); I != E; ++I) {
  DeclaratorChunk &Chunk = D.getTypeObject(I);

  // The only type information in the declarator which can come
  // before the declaration name is the base type of a member
  // pointer.
  if (Chunk.Kind != DeclaratorChunk::MemberPointer)
    continue;

  // Rebuild the scope specifier in-place.
  CXXScopeSpec &SS = Chunk.Mem.Scope();
  if (S.RebuildNestedNameSpecifierInCurrentInstantiation(SS))
    return true;
}

return false;
5626}

5628void Sema::warnOnReservedIdentifier(const NamedDecl *D) {
// Avoid warning twice on the same identifier, and don't warn on redeclaration
// of system decl.
if (D->getPreviousDecl() || D->isImplicit())
  return;
ReservedIdentifierStatus Status = D->isReserved(getLangOpts());
if (Status != ReservedIdentifierStatus::NotReserved &&
    !Context.getSourceManager().isInSystemHeader(D->getLocation()))
  Diag(D->getLocation(), diag::warn_reserved_extern_symbol)
      << D << static_cast<int>(Status);
5638}

5640Decl *Sema::ActOnDeclarator(Scope *S, Declarator &D) {
D.setFunctionDefinitionKind(FunctionDefinitionKind::Declaration);
Decl *Dcl = HandleDeclarator(S, D, MultiTemplateParamsArg());

if (OriginalLexicalContext && OriginalLexicalContext->isObjCContainer() &&
    Dcl && Dcl->getDeclContext()->isFileContext())
  Dcl->setTopLevelDeclInObjCContainer();

return Dcl;
5649}

5651/// DiagnoseClassNameShadow - Implement C++ [class.mem]p13:
5652///   If T is the name of a class, then each of the following shall have a
5653///   name different from T:
5654///     - every static data member of class T;
5655///     - every member function of class T
5656///     - every member of class T that is itself a type;
5657/// \returns true if the declaration name violates these rules.
5658bool Sema::DiagnoseClassNameShadow(DeclContext *DC,
                                 DeclarationNameInfo NameInfo) {
DeclarationName Name = NameInfo.getName();

CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC);
while (Record && Record->isAnonymousStructOrUnion())
  Record = dyn_cast<CXXRecordDecl>(Record->getParent());
if (Record && Record->getIdentifier() && Record->getDeclName() == Name) {
  Diag(NameInfo.getLoc(), diag::err_member_name_of_class) << Name;
  return true;
}

return false;
5671}

5673/// Diagnose a declaration whose declarator-id has the given
5674/// nested-name-specifier.
5675///
5676/// \param SS The nested-name-specifier of the declarator-id.
5677///
5678/// \param DC The declaration context to which the nested-name-specifier
5679/// resolves.
5680///
5681/// \param Name The name of the entity being declared.
5682///
5683/// \param Loc The location of the name of the entity being declared.
5684///
5685/// \param IsTemplateId Whether the name is a (simple-)template-id, and thus
5686/// we're declaring an explicit / partial specialization / instantiation.
5687///
5688/// \returns true if we cannot safely recover from this error, false otherwise.
5689bool Sema::diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
                                      DeclarationName Name,
                                      SourceLocation Loc, bool IsTemplateId) {
DeclContext *Cur = CurContext;
while (isa<LinkageSpecDecl>(Cur) || isa<CapturedDecl>(Cur))
  Cur = Cur->getParent();

// If the user provided a superfluous scope specifier that refers back to the
// class in which the entity is already declared, diagnose and ignore it.
//
// class X {
//   void X::f();
// };
//
// Note, it was once ill-formed to give redundant qualification in all
// contexts, but that rule was removed by DR482.
if (Cur->Equals(DC)) {
  if (Cur->isRecord()) {
    Diag(Loc, LangOpts.MicrosoftExt ? diag::warn_member_extra_qualification
                                    : diag::err_member_extra_qualification)
      << Name << FixItHint::CreateRemoval(SS.getRange());
    SS.clear();
  } else {
    Diag(Loc, diag::warn_namespace_member_extra_qualification) << Name;
  }
  return false;
}

// Check whether the qualifying scope encloses the scope of the original
// declaration. For a template-id, we perform the checks in
// CheckTemplateSpecializationScope.
if (!Cur->Encloses(DC) && !IsTemplateId) {
  if (Cur->isRecord())
    Diag(Loc, diag::err_member_qualification)
      << Name << SS.getRange();
  else if (isa<TranslationUnitDecl>(DC))
    Diag(Loc, diag::err_invalid_declarator_global_scope)
      << Name << SS.getRange();
  else if (isa<FunctionDecl>(Cur))
    Diag(Loc, diag::err_invalid_declarator_in_function)
      << Name << SS.getRange();
  else if (isa<BlockDecl>(Cur))
    Diag(Loc, diag::err_invalid_declarator_in_block)
      << Name << SS.getRange();
  else
    Diag(Loc, diag::err_invalid_declarator_scope)
    << Name << cast<NamedDecl>(Cur) << cast<NamedDecl>(DC) << SS.getRange();

  return true;
}

if (Cur->isRecord()) {
  // Cannot qualify members within a class.
  Diag(Loc, diag::err_member_qualification)
    << Name << SS.getRange();
  SS.clear();

  // C++ constructors and destructors with incorrect scopes can break
  // our AST invariants by having the wrong underlying types. If
  // that's the case, then drop this declaration entirely.
  if ((Name.getNameKind() == DeclarationName::CXXConstructorName ||
       Name.getNameKind() == DeclarationName::CXXDestructorName) &&
      !Context.hasSameType(Name.getCXXNameType(),
                           Context.getTypeDeclType(cast<CXXRecordDecl>(Cur))))
    return true;

  return false;
}

// C++11 [dcl.meaning]p1:
//   [...] "The nested-name-specifier of the qualified declarator-id shall
//   not begin with a decltype-specifer"
NestedNameSpecifierLoc SpecLoc(SS.getScopeRep(), SS.location_data());
while (SpecLoc.getPrefix())
  SpecLoc = SpecLoc.getPrefix();
if (dyn_cast_or_null<DecltypeType>(
      SpecLoc.getNestedNameSpecifier()->getAsType()))
  Diag(Loc, diag::err_decltype_in_declarator)
    << SpecLoc.getTypeLoc().getSourceRange();

return false;
5770}

5772NamedDecl *Sema::HandleDeclarator(Scope *S, Declarator &D,
                                MultiTemplateParamsArg TemplateParamLists) {
// TODO: consider using NameInfo for diagnostic.
DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
DeclarationName Name = NameInfo.getName();

// All of these full declarators require an identifier.  If it doesn't have
// one, the ParsedFreeStandingDeclSpec action should be used.
if (D.isDecompositionDeclarator()) {
  return ActOnDecompositionDeclarator(S, D, TemplateParamLists);
} else if (!Name) {
  if (!D.isInvalidType())  // Reject this if we think it is valid.
    Diag(D.getDeclSpec().getBeginLoc(), diag::err_declarator_need_ident)
        << D.getDeclSpec().getSourceRange() << D.getSourceRange();
  return nullptr;
} else if (DiagnoseUnexpandedParameterPack(NameInfo, UPPC_DeclarationType))
  return nullptr;

// The scope passed in may not be a decl scope.  Zip up the scope tree until
// we find one that is.
while ((S->getFlags() & Scope::DeclScope) == 0 ||
       (S->getFlags() & Scope::TemplateParamScope) != 0)
  S = S->getParent();

DeclContext *DC = CurContext;
if (D.getCXXScopeSpec().isInvalid())
  D.setInvalidType();
else if (D.getCXXScopeSpec().isSet()) {
  if (DiagnoseUnexpandedParameterPack(D.getCXXScopeSpec(),
                                      UPPC_DeclarationQualifier))
    return nullptr;

  bool EnteringContext = !D.getDeclSpec().isFriendSpecified();
  DC = computeDeclContext(D.getCXXScopeSpec(), EnteringContext);
  if (!DC || isa<EnumDecl>(DC)) {
    // If we could not compute the declaration context, it's because the
    // declaration context is dependent but does not refer to a class,
    // class template, or class template partial specialization. Complain
    // and return early, to avoid the coming semantic disaster.
    Diag(D.getIdentifierLoc(),
         diag::err_template_qualified_declarator_no_match)
      << D.getCXXScopeSpec().getScopeRep()
      << D.getCXXScopeSpec().getRange();
    return nullptr;
  }
  bool IsDependentContext = DC->isDependentContext();

  if (!IsDependentContext &&
      RequireCompleteDeclContext(D.getCXXScopeSpec(), DC))
    return nullptr;

  // If a class is incomplete, do not parse entities inside it.
  if (isa<CXXRecordDecl>(DC) && !cast<CXXRecordDecl>(DC)->hasDefinition()) {
    Diag(D.getIdentifierLoc(),
         diag::err_member_def_undefined_record)
      << Name << DC << D.getCXXScopeSpec().getRange();
    return nullptr;
  }
  if (!D.getDeclSpec().isFriendSpecified()) {
    if (diagnoseQualifiedDeclaration(
            D.getCXXScopeSpec(), DC, Name, D.getIdentifierLoc(),
            D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId)) {
      if (DC->isRecord())
        return nullptr;

      D.setInvalidType();
    }
  }

  // Check whether we need to rebuild the type of the given
  // declaration in the current instantiation.
  if (EnteringContext && IsDependentContext &&
      TemplateParamLists.size() != 0) {
    ContextRAII SavedContext(*this, DC);
    if (RebuildDeclaratorInCurrentInstantiation(*this, D, Name))
      D.setInvalidType();
  }
}

TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
QualType R = TInfo->getType();

if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
                                    UPPC_DeclarationType))
  D.setInvalidType();

LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
                      forRedeclarationInCurContext());

// See if this is a redefinition of a variable in the same scope.
if (!D.getCXXScopeSpec().isSet()) {
  bool IsLinkageLookup = false;
  bool CreateBuiltins = false;

  // If the declaration we're planning to build will be a function
  // or object with linkage, then look for another declaration with
  // linkage (C99 6.2.2p4-5 and C++ [basic.link]p6).
  //
  // If the declaration we're planning to build will be declared with
  // external linkage in the translation unit, create any builtin with
  // the same name.
  if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef)
    /* Do nothing*/;
  else if (CurContext->isFunctionOrMethod() &&
           (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_extern ||
            R->isFunctionType())) {
    IsLinkageLookup = true;
    CreateBuiltins =
        CurContext->getEnclosingNamespaceContext()->isTranslationUnit();
  } else if (CurContext->getRedeclContext()->isTranslationUnit() &&
             D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_static)
    CreateBuiltins = true;

  if (IsLinkageLookup) {
    Previous.clear(LookupRedeclarationWithLinkage);
    Previous.setRedeclarationKind(ForExternalRedeclaration);
  }

  LookupName(Previous, S, CreateBuiltins);
} else { // Something like "int foo::x;"
  LookupQualifiedName(Previous, DC);

  // C++ [dcl.meaning]p1:
  //   When the declarator-id is qualified, the declaration shall refer to a
  //  previously declared member of the class or namespace to which the
  //  qualifier refers (or, in the case of a namespace, of an element of the
  //  inline namespace set of that namespace (7.3.1)) or to a specialization
  //  thereof; [...]
  //
  // Note that we already checked the context above, and that we do not have
  // enough information to make sure that Previous contains the declaration
  // we want to match. For example, given:
  //
  //   class X {
  //     void f();
  //     void f(float);
  //   };
  //
  //   void X::f(int) { } // ill-formed
  //
  // In this case, Previous will point to the overload set
  // containing the two f's declared in X, but neither of them
  // matches.

  // C++ [dcl.meaning]p1:
  //   [...] the member shall not merely have been introduced by a
  //   using-declaration in the scope of the class or namespace nominated by
  //   the nested-name-specifier of the declarator-id.
  RemoveUsingDecls(Previous);
}

if (Previous.isSingleResult() &&
    Previous.getFoundDecl()->isTemplateParameter()) {
  // Maybe we will complain about the shadowed template parameter.
  if (!D.isInvalidType())
    DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
                                    Previous.getFoundDecl());

  // Just pretend that we didn't see the previous declaration.
  Previous.clear();
}

if (!R->isFunctionType() && DiagnoseClassNameShadow(DC, NameInfo))
  // Forget that the previous declaration is the injected-class-name.
  Previous.clear();

// In C++, the previous declaration we find might be a tag type
// (class or enum). In this case, the new declaration will hide the
// tag type. Note that this applies to functions, function templates, and
// variables, but not to typedefs (C++ [dcl.typedef]p4) or variable templates.
if (Previous.isSingleTagDecl() &&
    D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
    (TemplateParamLists.size() == 0 || R->isFunctionType()))
  Previous.clear();

// Check that there are no default arguments other than in the parameters
// of a function declaration (C++ only).
if (getLangOpts().CPlusPlus)
  CheckExtraCXXDefaultArguments(D);

NamedDecl *New;

bool AddToScope = true;
if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
  if (TemplateParamLists.size()) {
    Diag(D.getIdentifierLoc(), diag::err_template_typedef);
    return nullptr;
  }

  New = ActOnTypedefDeclarator(S, D, DC, TInfo, Previous);
} else if (R->isFunctionType()) {
  New = ActOnFunctionDeclarator(S, D, DC, TInfo, Previous,
                                TemplateParamLists,
                                AddToScope);
} else {
  New = ActOnVariableDeclarator(S, D, DC, TInfo, Previous, TemplateParamLists,
                                AddToScope);
}

if (!New)
  return nullptr;

// If this has an identifier and is not a function template specialization,
// add it to the scope stack.
if (New->getDeclName() && AddToScope)
  PushOnScopeChains(New, S);

if (isInOpenMPDeclareTargetContext())
  checkDeclIsAllowedInOpenMPTarget(nullptr, New);

return New;
5983}

5985/// Helper method to turn variable array types into constant array
5986/// types in certain situations which would otherwise be errors (for
5987/// GCC compatibility).
5988static QualType TryToFixInvalidVariablyModifiedType(QualType T,
                                                  ASTContext &Context,
                                                  bool &SizeIsNegative,
                                                  llvm::APSInt &Oversized) {
// This method tries to turn a variable array into a constant
// array even when the size isn't an ICE.  This is necessary
// for compatibility with code that depends on gcc's buggy
// constant expression folding, like struct {char x[(int)(char*)2];}
SizeIsNegative = false;
Oversized = 0;

if (T->isDependentType())
  return QualType();

QualifierCollector Qs;
const Type *Ty = Qs.strip(T);

if (const PointerType* PTy = dyn_cast<PointerType>(Ty)) {
  QualType Pointee = PTy->getPointeeType();
  QualType FixedType =
      TryToFixInvalidVariablyModifiedType(Pointee, Context, SizeIsNegative,
                                          Oversized);
  if (FixedType.isNull()) return FixedType;
  FixedType = Context.getPointerType(FixedType);
  return Qs.apply(Context, FixedType);
}
if (const ParenType* PTy = dyn_cast<ParenType>(Ty)) {
  QualType Inner = PTy->getInnerType();
  QualType FixedType =
      TryToFixInvalidVariablyModifiedType(Inner, Context, SizeIsNegative,
                                          Oversized);
  if (FixedType.isNull()) return FixedType;
  FixedType = Context.getParenType(FixedType);
  return Qs.apply(Context, FixedType);
}

const VariableArrayType* VLATy = dyn_cast<VariableArrayType>(T);
if (!VLATy)
  return QualType();

QualType ElemTy = VLATy->getElementType();
if (ElemTy->isVariablyModifiedType()) {
  ElemTy = TryToFixInvalidVariablyModifiedType(ElemTy, Context,
                                               SizeIsNegative, Oversized);
  if (ElemTy.isNull())
    return QualType();
}

Expr::EvalResult Result;
if (!VLATy->getSizeExpr() ||
    !VLATy->getSizeExpr()->EvaluateAsInt(Result, Context))
  return QualType();

llvm::APSInt Res = Result.Val.getInt();

// Check whether the array size is negative.
if (Res.isSigned() && Res.isNegative()) {
  SizeIsNegative = true;
  return QualType();
}

// Check whether the array is too large to be addressed.
unsigned ActiveSizeBits =
    (!ElemTy->isDependentType() && !ElemTy->isVariablyModifiedType() &&
     !ElemTy->isIncompleteType() && !ElemTy->isUndeducedType())
        ? ConstantArrayType::getNumAddressingBits(Context, ElemTy, Res)
        : Res.getActiveBits();
if (ActiveSizeBits > ConstantArrayType::getMaxSizeBits(Context)) {
  Oversized = Res;
  return QualType();
}

QualType FoldedArrayType = Context.getConstantArrayType(
    ElemTy, Res, VLATy->getSizeExpr(), ArrayType::Normal, 0);
return Qs.apply(Context, FoldedArrayType);
6063}

6065static void
6066FixInvalidVariablyModifiedTypeLoc(TypeLoc SrcTL, TypeLoc DstTL) {
SrcTL = SrcTL.getUnqualifiedLoc();
DstTL = DstTL.getUnqualifiedLoc();
if (PointerTypeLoc SrcPTL = SrcTL.getAs<PointerTypeLoc>()) {
  PointerTypeLoc DstPTL = DstTL.castAs<PointerTypeLoc>();
  FixInvalidVariablyModifiedTypeLoc(SrcPTL.getPointeeLoc(),
                                    DstPTL.getPointeeLoc());
  DstPTL.setStarLoc(SrcPTL.getStarLoc());
  return;
}
if (ParenTypeLoc SrcPTL = SrcTL.getAs<ParenTypeLoc>()) {
  ParenTypeLoc DstPTL = DstTL.castAs<ParenTypeLoc>();
  FixInvalidVariablyModifiedTypeLoc(SrcPTL.getInnerLoc(),
                                    DstPTL.getInnerLoc());
  DstPTL.setLParenLoc(SrcPTL.getLParenLoc());
  DstPTL.setRParenLoc(SrcPTL.getRParenLoc());
  return;
}
ArrayTypeLoc SrcATL = SrcTL.castAs<ArrayTypeLoc>();
ArrayTypeLoc DstATL = DstTL.castAs<ArrayTypeLoc>();
TypeLoc SrcElemTL = SrcATL.getElementLoc();
TypeLoc DstElemTL = DstATL.getElementLoc();
if (VariableArrayTypeLoc SrcElemATL =
        SrcElemTL.getAs<VariableArrayTypeLoc>()) {
  ConstantArrayTypeLoc DstElemATL = DstElemTL.castAs<ConstantArrayTypeLoc>();
  FixInvalidVariablyModifiedTypeLoc(SrcElemATL, DstElemATL);
} else {
  DstElemTL.initializeFullCopy(SrcElemTL);
}
DstATL.setLBracketLoc(SrcATL.getLBracketLoc());
DstATL.setSizeExpr(SrcATL.getSizeExpr());
DstATL.setRBracketLoc(SrcATL.getRBracketLoc());
6098}

6100/// Helper method to turn variable array types into constant array
6101/// types in certain situations which would otherwise be errors (for
6102/// GCC compatibility).
6103static TypeSourceInfo*
6104TryToFixInvalidVariablyModifiedTypeSourceInfo(TypeSourceInfo *TInfo,
                                            ASTContext &Context,
                                            bool &SizeIsNegative,
                                            llvm::APSInt &Oversized) {
QualType FixedTy
  = TryToFixInvalidVariablyModifiedType(TInfo->getType(), Context,
                                        SizeIsNegative, Oversized);
if (FixedTy.isNull())
  return nullptr;
TypeSourceInfo *FixedTInfo = Context.getTrivialTypeSourceInfo(FixedTy);
FixInvalidVariablyModifiedTypeLoc(TInfo->getTypeLoc(),
                                  FixedTInfo->getTypeLoc());
return FixedTInfo;
6117}

6119/// Attempt to fold a variable-sized type to a constant-sized type, returning
6120/// true if we were successful.
6121bool Sema::tryToFixVariablyModifiedVarType(TypeSourceInfo *&TInfo,
                                         QualType &T, SourceLocation Loc,
                                         unsigned FailedFoldDiagID) {
bool SizeIsNegative;
llvm::APSInt Oversized;
TypeSourceInfo *FixedTInfo = TryToFixInvalidVariablyModifiedTypeSourceInfo(
    TInfo, Context, SizeIsNegative, Oversized);
if (FixedTInfo) {
  Diag(Loc, diag::ext_vla_folded_to_constant);
  TInfo = FixedTInfo;
  T = FixedTInfo->getType();
  return true;
}

if (SizeIsNegative)
  Diag(Loc, diag::err_typecheck_negative_array_size);
else if (Oversized.getBoolValue())
  Diag(Loc, diag::err_array_too_large) << toString(Oversized, 10);
else if (FailedFoldDiagID)
  Diag(Loc, FailedFoldDiagID);
return false;
6142}

6144/// Register the given locally-scoped extern "C" declaration so
6145/// that it can be found later for redeclarations. We include any extern "C"
6146/// declaration that is not visible in the translation unit here, not just
6147/// function-scope declarations.
6148void
6149Sema::RegisterLocallyScopedExternCDecl(NamedDecl *ND, Scope *S) {
if (!getLangOpts().CPlusPlus &&
    ND->getLexicalDeclContext()->getRedeclContext()->isTranslationUnit())
  // Don't need to track declarations in the TU in C.
  return;

// Note that we have a locally-scoped external with this name.
Context.getExternCContextDecl()->makeDeclVisibleInContext(ND);
6157}

6159NamedDecl *Sema::findLocallyScopedExternCDecl(DeclarationName Name) {
// FIXME: We can have multiple results via __attribute__((overloadable)).
auto Result = Context.getExternCContextDecl()->lookup(Name);
return Result.empty() ? nullptr : *Result.begin();
6163}

6165/// Diagnose function specifiers on a declaration of an identifier that
6166/// does not identify a function.
6167void Sema::DiagnoseFunctionSpecifiers(const DeclSpec &DS) {
// FIXME: We should probably indicate the identifier in question to avoid
// confusion for constructs like "virtual int a(), b;"
if (DS.isVirtualSpecified())
  Diag(DS.getVirtualSpecLoc(),
       diag::err_virtual_non_function);

if (DS.hasExplicitSpecifier())
  Diag(DS.getExplicitSpecLoc(),
       diag::err_explicit_non_function);

if (DS.isNoreturnSpecified())
  Diag(DS.getNoreturnSpecLoc(),
       diag::err_noreturn_non_function);
6181}

6183NamedDecl*
6184Sema::ActOnTypedefDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                           TypeSourceInfo *TInfo, LookupResult &Previous) {
// Typedef declarators cannot be qualified (C++ [dcl.meaning]p1).
if (D.getCXXScopeSpec().isSet()) {
  Diag(D.getIdentifierLoc(), diag::err_qualified_typedef_declarator)
    << D.getCXXScopeSpec().getRange();
  D.setInvalidType();
  // Pretend we didn't see the scope specifier.
  DC = CurContext;
  Previous.clear();
}

DiagnoseFunctionSpecifiers(D.getDeclSpec());

if (D.getDeclSpec().isInlineSpecified())
  Diag(D.getDeclSpec().getInlineSpecLoc(), diag::err_inline_non_function)
      << getLangOpts().CPlusPlus17;
if (D.getDeclSpec().hasConstexprSpecifier())
  Diag(D.getDeclSpec().getConstexprSpecLoc(), diag::err_invalid_constexpr)
      << 1 << static_cast<int>(D.getDeclSpec().getConstexprSpecifier());

if (D.getName().Kind != UnqualifiedIdKind::IK_Identifier) {
  if (D.getName().Kind == UnqualifiedIdKind::IK_DeductionGuideName)
    Diag(D.getName().StartLocation,
         diag::err_deduction_guide_invalid_specifier)
        << "typedef";
  else
    Diag(D.getName().StartLocation, diag::err_typedef_not_identifier)
        << D.getName().getSourceRange();
  return nullptr;
}

TypedefDecl *NewTD = ParseTypedefDecl(S, D, TInfo->getType(), TInfo);
if (!NewTD) return nullptr;

// Handle attributes prior to checking for duplicates in MergeVarDecl
ProcessDeclAttributes(S, NewTD, D);

CheckTypedefForVariablyModifiedType(S, NewTD);

bool Redeclaration = D.isRedeclaration();
NamedDecl *ND = ActOnTypedefNameDecl(S, DC, NewTD, Previous, Redeclaration);
D.setRedeclaration(Redeclaration);
return ND;
6228}

6230void
6231Sema::CheckTypedefForVariablyModifiedType(Scope *S, TypedefNameDecl *NewTD) {
// C99 6.7.7p2: If a typedef name specifies a variably modified type
// then it shall have block scope.
// Note that variably modified types must be fixed before merging the decl so
// that redeclarations will match.
TypeSourceInfo *TInfo = NewTD->getTypeSourceInfo();
QualType T = TInfo->getType();
if (T->isVariablyModifiedType()) {
  setFunctionHasBranchProtectedScope();

  if (S->getFnParent() == nullptr) {
    bool SizeIsNegative;
    llvm::APSInt Oversized;
    TypeSourceInfo *FixedTInfo =
      TryToFixInvalidVariablyModifiedTypeSourceInfo(TInfo, Context,
                                                    SizeIsNegative,
                                                    Oversized);
    if (FixedTInfo) {
      Diag(NewTD->getLocation(), diag::ext_vla_folded_to_constant);
      NewTD->setTypeSourceInfo(FixedTInfo);
    } else {
      if (SizeIsNegative)
        Diag(NewTD->getLocation(), diag::err_typecheck_negative_array_size);
      else if (T->isVariableArrayType())
        Diag(NewTD->getLocation(), diag::err_vla_decl_in_file_scope);
      else if (Oversized.getBoolValue())
        Diag(NewTD->getLocation(), diag::err_array_too_large)
          << toString(Oversized, 10);
      else
        Diag(NewTD->getLocation(), diag::err_vm_decl_in_file_scope);
      NewTD->setInvalidDecl();
    }
  }
}
6265}

6267/// ActOnTypedefNameDecl - Perform semantic checking for a declaration which
6268/// declares a typedef-name, either using the 'typedef' type specifier or via
6269/// a C++0x [dcl.typedef]p2 alias-declaration: 'using T = A;'.
6270NamedDecl*
6271Sema::ActOnTypedefNameDecl(Scope *S, DeclContext *DC, TypedefNameDecl *NewTD,
                         LookupResult &Previous, bool &Redeclaration) {

// Find the shadowed declaration before filtering for scope.
NamedDecl *ShadowedDecl = getShadowedDeclaration(NewTD, Previous);

// Merge the decl with the existing one if appropriate. If the decl is
// in an outer scope, it isn't the same thing.
FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage*/false,
                     /*AllowInlineNamespace*/false);
filterNonConflictingPreviousTypedefDecls(*this, NewTD, Previous);
if (!Previous.empty()) {
  Redeclaration = true;
  MergeTypedefNameDecl(S, NewTD, Previous);
} else {
  inferGslPointerAttribute(NewTD);
}

if (ShadowedDecl && !Redeclaration)
  CheckShadow(NewTD, ShadowedDecl, Previous);

// If this is the C FILE type, notify the AST context.
if (IdentifierInfo *II = NewTD->getIdentifier())
  if (!NewTD->isInvalidDecl() &&
      NewTD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
    if (II->isStr("FILE"))
      Context.setFILEDecl(NewTD);
    else if (II->isStr("jmp_buf"))
      Context.setjmp_bufDecl(NewTD);
    else if (II->isStr("sigjmp_buf"))
      Context.setsigjmp_bufDecl(NewTD);
    else if (II->isStr("ucontext_t"))
      Context.setucontext_tDecl(NewTD);
  }

return NewTD;
6307}

6309/// Determines whether the given declaration is an out-of-scope
6310/// previous declaration.
6311///
6312/// This routine should be invoked when name lookup has found a
6313/// previous declaration (PrevDecl) that is not in the scope where a
6314/// new declaration by the same name is being introduced. If the new
6315/// declaration occurs in a local scope, previous declarations with
6316/// linkage may still be considered previous declarations (C99
6317/// 6.2.2p4-5, C++ [basic.link]p6).
6318///
6319/// \param PrevDecl the previous declaration found by name
6320/// lookup
6321///
6322/// \param DC the context in which the new declaration is being
6323/// declared.
6324///
6325/// \returns true if PrevDecl is an out-of-scope previous declaration
6326/// for a new delcaration with the same name.
6327static bool
6328isOutOfScopePreviousDeclaration(NamedDecl *PrevDecl, DeclContext *DC,
                              ASTContext &Context) {
if (!PrevDecl)
  return false;

if (!PrevDecl->hasLinkage())
  return false;

if (Context.getLangOpts().CPlusPlus) {
  // C++ [basic.link]p6:
  //   If there is a visible declaration of an entity with linkage
  //   having the same name and type, ignoring entities declared
  //   outside the innermost enclosing namespace scope, the block
  //   scope declaration declares that same entity and receives the
  //   linkage of the previous declaration.
  DeclContext *OuterContext = DC->getRedeclContext();
  if (!OuterContext->isFunctionOrMethod())
    // This rule only applies to block-scope declarations.
    return false;

  DeclContext *PrevOuterContext = PrevDecl->getDeclContext();
  if (PrevOuterContext->isRecord())
    // We found a member function: ignore it.
    return false;

  // Find the innermost enclosing namespace for the new and
  // previous declarations.
  OuterContext = OuterContext->getEnclosingNamespaceContext();
  PrevOuterContext = PrevOuterContext->getEnclosingNamespaceContext();

  // The previous declaration is in a different namespace, so it
  // isn't the same function.
  if (!OuterContext->Equals(PrevOuterContext))
    return false;
}

return true;
6365}

6367static void SetNestedNameSpecifier(Sema &S, DeclaratorDecl *DD, Declarator &D) {
CXXScopeSpec &SS = D.getCXXScopeSpec();
if (!SS.isSet()) return;
DD->setQualifierInfo(SS.getWithLocInContext(S.Context));
6371}

6373bool Sema::inferObjCARCLifetime(ValueDecl *decl) {
QualType type = decl->getType();
Qualifiers::ObjCLifetime lifetime = type.getObjCLifetime();
if (lifetime == Qualifiers::OCL_Autoreleasing) {
  // Various kinds of declaration aren't allowed to be __autoreleasing.
  unsigned kind = -1U;
  if (VarDecl *var = dyn_cast<VarDecl>(decl)) {
    if (var->hasAttr<BlocksAttr>())
      kind = 0; // __block
    else if (!var->hasLocalStorage())
      kind = 1; // global
  } else if (isa<ObjCIvarDecl>(decl)) {
    kind = 3; // ivar
  } else if (isa<FieldDecl>(decl)) {
    kind = 2; // field
  }

  if (kind != -1U) {
    Diag(decl->getLocation(), diag::err_arc_autoreleasing_var)
      << kind;
  }
} else if (lifetime == Qualifiers::OCL_None) {
  // Try to infer lifetime.
  if (!type->isObjCLifetimeType())
    return false;

  lifetime = type->getObjCARCImplicitLifetime();
  type = Context.getLifetimeQualifiedType(type, lifetime);
  decl->setType(type);
}

if (VarDecl *var = dyn_cast<VarDecl>(decl)) {
  // Thread-local variables cannot have lifetime.
  if (lifetime && lifetime != Qualifiers::OCL_ExplicitNone &&
      var->getTLSKind()) {
    Diag(var->getLocation(), diag::err_arc_thread_ownership)
      << var->getType();
    return true;
  }
}

return false;
6415}

6417void Sema::deduceOpenCLAddressSpace(ValueDecl *Decl) {
if (Decl->getType().hasAddressSpace())
  return;
if (Decl->getType()->isDependentType())
  return;
if (VarDecl *Var = dyn_cast<VarDecl>(Decl)) {
  QualType Type = Var->getType();
  if (Type->isSamplerT() || Type->isVoidType())
    return;
  LangAS ImplAS = LangAS::opencl_private;
  // OpenCL C v3.0 s6.7.8 - For OpenCL C 2.0 or with the
  // __opencl_c_program_scope_global_variables feature, the address space
  // for a variable at program scope or a static or extern variable inside
  // a function are inferred to be __global.
  if (getOpenCLOptions().areProgramScopeVariablesSupported(getLangOpts()) &&
      Var->hasGlobalStorage())
    ImplAS = LangAS::opencl_global;
  // If the original type from a decayed type is an array type and that array
  // type has no address space yet, deduce it now.
  if (auto DT = dyn_cast<DecayedType>(Type)) {
    auto OrigTy = DT->getOriginalType();
    if (!OrigTy.hasAddressSpace() && OrigTy->isArrayType()) {
      // Add the address space to the original array type and then propagate
      // that to the element type through `getAsArrayType`.
      OrigTy = Context.getAddrSpaceQualType(OrigTy, ImplAS);
      OrigTy = QualType(Context.getAsArrayType(OrigTy), 0);
      // Re-generate the decayed type.
      Type = Context.getDecayedType(OrigTy);
    }
  }
  Type = Context.getAddrSpaceQualType(Type, ImplAS);
  // Apply any qualifiers (including address space) from the array type to
  // the element type. This implements C99 6.7.3p8: "If the specification of
  // an array type includes any type qualifiers, the element type is so
  // qualified, not the array type."
  if (Type->isArrayType())
    Type = QualType(Context.getAsArrayType(Type), 0);
  Decl->setType(Type);
}
6456}

6458static void checkAttributesAfterMerging(Sema &S, NamedDecl &ND) {
// Ensure that an auto decl is deduced otherwise the checks below might cache
// the wrong linkage.
assert(S.ParsingInitForAutoVars.count(&ND) == 0)((void)0);

// 'weak' only applies to declarations with external linkage.
if (WeakAttr *Attr = ND.getAttr<WeakAttr>()) {
  if (!ND.isExternallyVisible()) {
    S.Diag(Attr->getLocation(), diag::err_attribute_weak_static);
    ND.dropAttr<WeakAttr>();
  }
}
if (WeakRefAttr *Attr = ND.getAttr<WeakRefAttr>()) {
  if (ND.isExternallyVisible()) {
    S.Diag(Attr->getLocation(), diag::err_attribute_weakref_not_static);
    ND.dropAttr<WeakRefAttr>();
    ND.dropAttr<AliasAttr>();
  }
}

if (auto *VD = dyn_cast<VarDecl>(&ND)) {
  if (VD->hasInit()) {
    if (const auto *Attr = VD->getAttr<AliasAttr>()) {
      assert(VD->isThisDeclarationADefinition() &&((void)0)
             !VD->isExternallyVisible() && "Broken AliasAttr handled late!")((void)0);
      S.Diag(Attr->getLocation(), diag::err_alias_is_definition) << VD << 0;
      VD->dropAttr<AliasAttr>();
    }
  }
}

// 'selectany' only applies to externally visible variable declarations.
// It does not apply to functions.
if (SelectAnyAttr *Attr = ND.getAttr<SelectAnyAttr>()) {
  if (isa<FunctionDecl>(ND) || !ND.isExternallyVisible()) {
    S.Diag(Attr->getLocation(),
           diag::err_attribute_selectany_non_extern_data);
    ND.dropAttr<SelectAnyAttr>();
  }
}

if (const InheritableAttr *Attr = getDLLAttr(&ND)) {
  auto *VD = dyn_cast<VarDecl>(&ND);
  bool IsAnonymousNS = false;
  bool IsMicrosoft = S.Context.getTargetInfo().getCXXABI().isMicrosoft();
  if (VD) {
    const NamespaceDecl *NS = dyn_cast<NamespaceDecl>(VD->getDeclContext());
    while (NS && !IsAnonymousNS) {
      IsAnonymousNS = NS->isAnonymousNamespace();
      NS = dyn_cast<NamespaceDecl>(NS->getParent());
    }
  }
  // dll attributes require external linkage. Static locals may have external
  // linkage but still cannot be explicitly imported or exported.
  // In Microsoft mode, a variable defined in anonymous namespace must have
  // external linkage in order to be exported.
  bool AnonNSInMicrosoftMode = IsAnonymousNS && IsMicrosoft;
  if ((ND.isExternallyVisible() && AnonNSInMicrosoftMode) ||
      (!AnonNSInMicrosoftMode &&
       (!ND.isExternallyVisible() || (VD && VD->isStaticLocal())))) {
    S.Diag(ND.getLocation(), diag::err_attribute_dll_not_extern)
      << &ND << Attr;
    ND.setInvalidDecl();
  }
}

// Check the attributes on the function type, if any.
if (const auto *FD = dyn_cast<FunctionDecl>(&ND)) {
  // Don't declare this variable in the second operand of the for-statement;
  // GCC miscompiles that by ending its lifetime before evaluating the
  // third operand. See gcc.gnu.org/PR86769.
  AttributedTypeLoc ATL;
  for (TypeLoc TL = FD->getTypeSourceInfo()->getTypeLoc();
       (ATL = TL.getAsAdjusted<AttributedTypeLoc>());
       TL = ATL.getModifiedLoc()) {
    // The [[lifetimebound]] attribute can be applied to the implicit object
    // parameter of a non-static member function (other than a ctor or dtor)
    // by applying it to the function type.
    if (const auto *A = ATL.getAttrAs<LifetimeBoundAttr>()) {
      const auto *MD = dyn_cast<CXXMethodDecl>(FD);
      if (!MD || MD->isStatic()) {
        S.Diag(A->getLocation(), diag::err_lifetimebound_no_object_param)
            << !MD << A->getRange();
      } else if (isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD)) {
        S.Diag(A->getLocation(), diag::err_lifetimebound_ctor_dtor)
            << isa<CXXDestructorDecl>(MD) << A->getRange();
      }
    }
  }
}
6548}

6550static void checkDLLAttributeRedeclaration(Sema &S, NamedDecl *OldDecl,
                                         NamedDecl *NewDecl,
                                         bool IsSpecialization,
                                         bool IsDefinition) {
if (OldDecl->isInvalidDecl() || NewDecl->isInvalidDecl())
  return;

bool IsTemplate = false;
if (TemplateDecl *OldTD = dyn_cast<TemplateDecl>(OldDecl)) {
  OldDecl = OldTD->getTemplatedDecl();
  IsTemplate = true;
  if (!IsSpecialization)
    IsDefinition = false;
}
if (TemplateDecl *NewTD = dyn_cast<TemplateDecl>(NewDecl)) {
  NewDecl = NewTD->getTemplatedDecl();
  IsTemplate = true;
}

if (!OldDecl || !NewDecl)
  return;

const DLLImportAttr *OldImportAttr = OldDecl->getAttr<DLLImportAttr>();
const DLLExportAttr *OldExportAttr = OldDecl->getAttr<DLLExportAttr>();
const DLLImportAttr *NewImportAttr = NewDecl->getAttr<DLLImportAttr>();
const DLLExportAttr *NewExportAttr = NewDecl->getAttr<DLLExportAttr>();

// dllimport and dllexport are inheritable attributes so we have to exclude
// inherited attribute instances.
bool HasNewAttr = (NewImportAttr && !NewImportAttr->isInherited()) ||
                  (NewExportAttr && !NewExportAttr->isInherited());

// A redeclaration is not allowed to add a dllimport or dllexport attribute,
// the only exception being explicit specializations.
// Implicitly generated declarations are also excluded for now because there
// is no other way to switch these to use dllimport or dllexport.
bool AddsAttr = !(OldImportAttr || OldExportAttr) && HasNewAttr;

if (AddsAttr && !IsSpecialization && !OldDecl->isImplicit()) {
  // Allow with a warning for free functions and global variables.
  bool JustWarn = false;
  if (!OldDecl->isCXXClassMember()) {
    auto *VD = dyn_cast<VarDecl>(OldDecl);
    if (VD && !VD->getDescribedVarTemplate())
      JustWarn = true;
    auto *FD = dyn_cast<FunctionDecl>(OldDecl);
    if (FD && FD->getTemplatedKind() == FunctionDecl::TK_NonTemplate)
      JustWarn = true;
  }

  // We cannot change a declaration that's been used because IR has already
  // been emitted. Dllimported functions will still work though (modulo
  // address equality) as they can use the thunk.
  if (OldDecl->isUsed())
    if (!isa<FunctionDecl>(OldDecl) || !NewImportAttr)
      JustWarn = false;

  unsigned DiagID = JustWarn ? diag::warn_attribute_dll_redeclaration
                             : diag::err_attribute_dll_redeclaration;
  S.Diag(NewDecl->getLocation(), DiagID)
      << NewDecl
      << (NewImportAttr ? (const Attr *)NewImportAttr : NewExportAttr);
  S.Diag(OldDecl->getLocation(), diag::note_previous_declaration);
  if (!JustWarn) {
    NewDecl->setInvalidDecl();
    return;
  }
}

// A redeclaration is not allowed to drop a dllimport attribute, the only
// exceptions being inline function definitions (except for function
// templates), local extern declarations, qualified friend declarations or
// special MSVC extension: in the last case, the declaration is treated as if
// it were marked dllexport.
bool IsInline = false, IsStaticDataMember = false, IsQualifiedFriend = false;
bool IsMicrosoftABI  = S.Context.getTargetInfo().shouldDLLImportComdatSymbols();
if (const auto *VD = dyn_cast<VarDecl>(NewDecl)) {
  // Ignore static data because out-of-line definitions are diagnosed
  // separately.
  IsStaticDataMember = VD->isStaticDataMember();
  IsDefinition = VD->isThisDeclarationADefinition(S.Context) !=
                 VarDecl::DeclarationOnly;
} else if (const auto *FD = dyn_cast<FunctionDecl>(NewDecl)) {
  IsInline = FD->isInlined();
  IsQualifiedFriend = FD->getQualifier() &&
                      FD->getFriendObjectKind() == Decl::FOK_Declared;
}

if (OldImportAttr && !HasNewAttr &&
    (!IsInline || (IsMicrosoftABI && IsTemplate)) && !IsStaticDataMember &&
    !NewDecl->isLocalExternDecl() && !IsQualifiedFriend) {
  if (IsMicrosoftABI && IsDefinition) {
    S.Diag(NewDecl->getLocation(),
           diag::warn_redeclaration_without_import_attribute)
        << NewDecl;
    S.Diag(OldDecl->getLocation(), diag::note_previous_declaration);
    NewDecl->dropAttr<DLLImportAttr>();
    NewDecl->addAttr(
        DLLExportAttr::CreateImplicit(S.Context, NewImportAttr->getRange()));
  } else {
    S.Diag(NewDecl->getLocation(),
           diag::warn_redeclaration_without_attribute_prev_attribute_ignored)
        << NewDecl << OldImportAttr;
    S.Diag(OldDecl->getLocation(), diag::note_previous_declaration);
    S.Diag(OldImportAttr->getLocation(), diag::note_previous_attribute);
    OldDecl->dropAttr<DLLImportAttr>();
    NewDecl->dropAttr<DLLImportAttr>();
  }
} else if (IsInline && OldImportAttr && !IsMicrosoftABI) {
  // In MinGW, seeing a function declared inline drops the dllimport
  // attribute.
  OldDecl->dropAttr<DLLImportAttr>();
  NewDecl->dropAttr<DLLImportAttr>();
  S.Diag(NewDecl->getLocation(),
         diag::warn_dllimport_dropped_from_inline_function)
      << NewDecl << OldImportAttr;
}

// A specialization of a class template member function is processed here
// since it's a redeclaration. If the parent class is dllexport, the
// specialization inherits that attribute. This doesn't happen automatically
// since the parent class isn't instantiated until later.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewDecl)) {
  if (MD->getTemplatedKind() == FunctionDecl::TK_MemberSpecialization &&
      !NewImportAttr && !NewExportAttr) {
    if (const DLLExportAttr *ParentExportAttr =
            MD->getParent()->getAttr<DLLExportAttr>()) {
      DLLExportAttr *NewAttr = ParentExportAttr->clone(S.Context);
      NewAttr->setInherited(true);
      NewDecl->addAttr(NewAttr);
    }
  }
}
6683}

6685/// Given that we are within the definition of the given function,
6686/// will that definition behave like C99's 'inline', where the
6687/// definition is discarded except for optimization purposes?
6688static bool isFunctionDefinitionDiscarded(Sema &S, FunctionDecl *FD) {
// Try to avoid calling GetGVALinkageForFunction.

// All cases of this require the 'inline' keyword.
if (!FD->isInlined()) return false;

// This is only possible in C++ with the gnu_inline attribute.
if (S.getLangOpts().CPlusPlus && !FD->hasAttr<GNUInlineAttr>())
  return false;

// Okay, go ahead and call the relatively-more-expensive function.
return S.Context.GetGVALinkageForFunction(FD) == GVA_AvailableExternally;
6700}

6702/// Determine whether a variable is extern "C" prior to attaching
6703/// an initializer. We can't just call isExternC() here, because that
6704/// will also compute and cache whether the declaration is externally
6705/// visible, which might change when we attach the initializer.
6706///
6707/// This can only be used if the declaration is known to not be a
6708/// redeclaration of an internal linkage declaration.
6709///
6710/// For instance:
6711///
6712///   auto x = []{};
6713///
6714/// Attaching the initializer here makes this declaration not externally
6715/// visible, because its type has internal linkage.
6716///
6717/// FIXME: This is a hack.
6718template<typename T>
6719static bool isIncompleteDeclExternC(Sema &S, const T *D) {
if (S.getLangOpts().CPlusPlus) {
  // In C++, the overloadable attribute negates the effects of extern "C".
  if (!D->isInExternCContext() || D->template hasAttr<OverloadableAttr>())
    return false;

  // So do CUDA's host/device attributes.
  if (S.getLangOpts().CUDA && (D->template hasAttr<CUDADeviceAttr>() ||
                               D->template hasAttr<CUDAHostAttr>()))
    return false;
}
return D->isExternC();
6731}

6733static bool shouldConsiderLinkage(const VarDecl *VD) {
const DeclContext *DC = VD->getDeclContext()->getRedeclContext();
if (DC->isFunctionOrMethod() || isa<OMPDeclareReductionDecl>(DC) ||
    isa<OMPDeclareMapperDecl>(DC))
  return VD->hasExternalStorage();
if (DC->isFileContext())
  return true;
if (DC->isRecord())
  return false;
if (isa<RequiresExprBodyDecl>(DC))
  return false;
llvm_unreachable("Unexpected context")__builtin_unreachable();
6745}

6747static bool shouldConsiderLinkage(const FunctionDecl *FD) {
const DeclContext *DC = FD->getDeclContext()->getRedeclContext();
if (DC->isFileContext() || DC->isFunctionOrMethod() ||
    isa<OMPDeclareReductionDecl>(DC) || isa<OMPDeclareMapperDecl>(DC))
  return true;
if (DC->isRecord())
  return false;
llvm_unreachable("Unexpected context")__builtin_unreachable();
6755}

6757static bool hasParsedAttr(Scope *S, const Declarator &PD,
                        ParsedAttr::Kind Kind) {
// Check decl attributes on the DeclSpec.
if (PD.getDeclSpec().getAttributes().hasAttribute(Kind))
  return true;

// Walk the declarator structure, checking decl attributes that were in a type
// position to the decl itself.
for (unsigned I = 0, E = PD.getNumTypeObjects(); I != E; ++I) {
  if (PD.getTypeObject(I).getAttrs().hasAttribute(Kind))
    return true;
}

// Finally, check attributes on the decl itself.
return PD.getAttributes().hasAttribute(Kind);
6772}

6774/// Adjust the \c DeclContext for a function or variable that might be a
6775/// function-local external declaration.
6776bool Sema::adjustContextForLocalExternDecl(DeclContext *&DC) {
if (!DC->isFunctionOrMethod())
  return false;

// If this is a local extern function or variable declared within a function
// template, don't add it into the enclosing namespace scope until it is
// instantiated; it might have a dependent type right now.
if (DC->isDependentContext())
  return true;

// C++11 [basic.link]p7:
//   When a block scope declaration of an entity with linkage is not found to
//   refer to some other declaration, then that entity is a member of the
//   innermost enclosing namespace.
//
// Per C++11 [namespace.def]p6, the innermost enclosing namespace is a
// semantically-enclosing namespace, not a lexically-enclosing one.
while (!DC->isFileContext() && !isa<LinkageSpecDecl>(DC))
  DC = DC->getParent();
return true;
6796}

6798/// Returns true if given declaration has external C language linkage.
6799static bool isDeclExternC(const Decl *D) {
if (const auto *FD = dyn_cast<FunctionDecl>(D))
  return FD->isExternC();
if (const auto *VD = dyn_cast<VarDecl>(D))
  return VD->isExternC();

llvm_unreachable("Unknown type of decl!")__builtin_unreachable();
6806}

6808/// Returns true if there hasn't been any invalid type diagnosed.
6809static bool diagnoseOpenCLTypes(Sema &Se, VarDecl *NewVD) {
DeclContext *DC = NewVD->getDeclContext();
QualType R = NewVD->getType();

// OpenCL v2.0 s6.9.b - Image type can only be used as a function argument.
// OpenCL v2.0 s6.13.16.1 - Pipe type can only be used as a function
// argument.
if (R->isImageType() || R->isPipeType()) {
  Se.Diag(NewVD->getLocation(),
          diag::err_opencl_type_can_only_be_used_as_function_parameter)
      << R;
  NewVD->setInvalidDecl();
  return false;
}

// OpenCL v1.2 s6.9.r:
// The event type cannot be used to declare a program scope variable.
// OpenCL v2.0 s6.9.q:
// The clk_event_t and reserve_id_t types cannot be declared in program
// scope.
if (NewVD->hasGlobalStorage() && !NewVD->isStaticLocal()) {
  if (R->isReserveIDT() || R->isClkEventT() || R->isEventT()) {
    Se.Diag(NewVD->getLocation(),
            diag::err_invalid_type_for_program_scope_var)
        << R;
    NewVD->setInvalidDecl();
    return false;
  }
}

// OpenCL v1.0 s6.8.a.3: Pointers to functions are not allowed.
if (!Se.getOpenCLOptions().isAvailableOption("__cl_clang_function_pointers",
                                             Se.getLangOpts())) {
  QualType NR = R.getCanonicalType();
  while (NR->isPointerType() || NR->isMemberFunctionPointerType() ||
         NR->isReferenceType()) {
    if (NR->isFunctionPointerType() || NR->isMemberFunctionPointerType() ||
        NR->isFunctionReferenceType()) {
      Se.Diag(NewVD->getLocation(), diag::err_opencl_function_pointer)
          << NR->isReferenceType();
      NewVD->setInvalidDecl();
      return false;
    }
    NR = NR->getPointeeType();
  }
}

if (!Se.getOpenCLOptions().isAvailableOption("cl_khr_fp16",
                                             Se.getLangOpts())) {
  // OpenCL v1.2 s6.1.1.1: reject declaring variables of the half and
  // half array type (unless the cl_khr_fp16 extension is enabled).
  if (Se.Context.getBaseElementType(R)->isHalfType()) {
    Se.Diag(NewVD->getLocation(), diag::err_opencl_half_declaration) << R;
    NewVD->setInvalidDecl();
    return false;
  }
}

// OpenCL v1.2 s6.9.r:
// The event type cannot be used with the __local, __constant and __global
// address space qualifiers.
if (R->isEventT()) {
  if (R.getAddressSpace() != LangAS::opencl_private) {
    Se.Diag(NewVD->getBeginLoc(), diag::err_event_t_addr_space_qual);
    NewVD->setInvalidDecl();
    return false;
  }
}

if (R->isSamplerT()) {
  // OpenCL v1.2 s6.9.b p4:
  // The sampler type cannot be used with the __local and __global address
  // space qualifiers.
  if (R.getAddressSpace() == LangAS::opencl_local ||
      R.getAddressSpace() == LangAS::opencl_global) {
    Se.Diag(NewVD->getLocation(), diag::err_wrong_sampler_addressspace);
    NewVD->setInvalidDecl();
  }

  // OpenCL v1.2 s6.12.14.1:
  // A global sampler must be declared with either the constant address
  // space qualifier or with the const qualifier.
  if (DC->isTranslationUnit() &&
      !(R.getAddressSpace() == LangAS::opencl_constant ||
        R.isConstQualified())) {
    Se.Diag(NewVD->getLocation(), diag::err_opencl_nonconst_global_sampler);
    NewVD->setInvalidDecl();
  }
  if (NewVD->isInvalidDecl())
    return false;
}

return true;
6902}

6904template <typename AttrTy>
6905static void copyAttrFromTypedefToDecl(Sema &S, Decl *D, const TypedefType *TT) {
const TypedefNameDecl *TND = TT->getDecl();
if (const auto *Attribute = TND->getAttr<AttrTy>()) {
  AttrTy *Clone = Attribute->clone(S.Context);
  Clone->setInherited(true);
  D->addAttr(Clone);
}
6912}

6914NamedDecl *Sema::ActOnVariableDeclarator(
  Scope *S, Declarator &D, DeclContext *DC, TypeSourceInfo *TInfo,
  LookupResult &Previous, MultiTemplateParamsArg TemplateParamLists,
  bool &AddToScope, ArrayRef<BindingDecl *> Bindings) {
QualType R = TInfo->getType();
DeclarationName Name = GetNameForDeclarator(D).getName();

IdentifierInfo *II = Name.getAsIdentifierInfo();

if (D.isDecompositionDeclarator()) {
  // Take the name of the first declarator as our name for diagnostic
  // purposes.
  auto &Decomp = D.getDecompositionDeclarator();
  if (!Decomp.bindings().empty()) {
    II = Decomp.bindings()[0].Name;
    Name = II;
  }
} else if (!II) {
  Diag(D.getIdentifierLoc(), diag::err_bad_variable_name) << Name;
  return nullptr;
}


DeclSpec::SCS SCSpec = D.getDeclSpec().getStorageClassSpec();
StorageClass SC = StorageClassSpecToVarDeclStorageClass(D.getDeclSpec());

// dllimport globals without explicit storage class are treated as extern. We
// have to change the storage class this early to get the right DeclContext.
if (SC == SC_None && !DC->isRecord() &&
    hasParsedAttr(S, D, ParsedAttr::AT_DLLImport) &&
    !hasParsedAttr(S, D, ParsedAttr::AT_DLLExport))
  SC = SC_Extern;

DeclContext *OriginalDC = DC;
bool IsLocalExternDecl = SC == SC_Extern &&
                         adjustContextForLocalExternDecl(DC);

if (SCSpec == DeclSpec::SCS_mutable) {
  // mutable can only appear on non-static class members, so it's always
  // an error here
  Diag(D.getIdentifierLoc(), diag::err_mutable_nonmember);
  D.setInvalidType();
  SC = SC_None;
}

if (getLangOpts().CPlusPlus11 && SCSpec == DeclSpec::SCS_register &&
    !D.getAsmLabel() && !getSourceManager().isInSystemMacro(
                            D.getDeclSpec().getStorageClassSpecLoc())) {
  // In C++11, the 'register' storage class specifier is deprecated.
  // Suppress the warning in system macros, it's used in macros in some
  // popular C system headers, such as in glibc's htonl() macro.
  Diag(D.getDeclSpec().getStorageClassSpecLoc(),
       getLangOpts().CPlusPlus17 ? diag::ext_register_storage_class
                                 : diag::warn_deprecated_register)
    << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
}

DiagnoseFunctionSpecifiers(D.getDeclSpec());

if (!DC->isRecord() && S->getFnParent() == nullptr) {
  // C99 6.9p2: The storage-class specifiers auto and register shall not
  // appear in the declaration specifiers in an external declaration.
  // Global Register+Asm is a GNU extension we support.
  if (SC == SC_Auto || (SC == SC_Register && !D.getAsmLabel())) {
    Diag(D.getIdentifierLoc(), diag::err_typecheck_sclass_fscope);
    D.setInvalidType();
  }
}

// If this variable has a VLA type and an initializer, try to
// fold to a constant-sized type. This is otherwise invalid.
if (D.hasInitializer() && R->isVariableArrayType())
  tryToFixVariablyModifiedVarType(TInfo, R, D.getIdentifierLoc(),
                                  /*DiagID=*/0);

bool IsMemberSpecialization = false;
bool IsVariableTemplateSpecialization = false;
bool IsPartialSpecialization = false;
bool IsVariableTemplate = false;
VarDecl *NewVD = nullptr;
VarTemplateDecl *NewTemplate = nullptr;
TemplateParameterList *TemplateParams = nullptr;
if (!getLangOpts().CPlusPlus) {
  NewVD = VarDecl::Create(Context, DC, D.getBeginLoc(), D.getIdentifierLoc(),
                          II, R, TInfo, SC);

  if (R->getContainedDeducedType())
    ParsingInitForAutoVars.insert(NewVD);

  if (D.isInvalidType())
    NewVD->setInvalidDecl();

  if (NewVD->getType().hasNonTrivialToPrimitiveDestructCUnion() &&
      NewVD->hasLocalStorage())
    checkNonTrivialCUnion(NewVD->getType(), NewVD->getLocation(),
                          NTCUC_AutoVar, NTCUK_Destruct);
} else {
  bool Invalid = false;

  if (DC->isRecord() && !CurContext->isRecord()) {
    // This is an out-of-line definition of a static data member.
    switch (SC) {
    case SC_None:
      break;
    case SC_Static:
      Diag(D.getDeclSpec().getStorageClassSpecLoc(),
           diag::err_static_out_of_line)
        << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
      break;
    case SC_Auto:
    case SC_Register:
    case SC_Extern:
      // [dcl.stc] p2: The auto or register specifiers shall be applied only
      // to names of variables declared in a block or to function parameters.
      // [dcl.stc] p6: The extern specifier cannot be used in the declaration
      // of class members

      Diag(D.getDeclSpec().getStorageClassSpecLoc(),
           diag::err_storage_class_for_static_member)
        << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
      break;
    case SC_PrivateExtern:
      llvm_unreachable("C storage class in c++!")__builtin_unreachable();
    }
  }

  if (SC == SC_Static && CurContext->isRecord()) {
    if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(DC)) {
      // Walk up the enclosing DeclContexts to check for any that are
      // incompatible with static data members.
      const DeclContext *FunctionOrMethod = nullptr;
      const CXXRecordDecl *AnonStruct = nullptr;
      for (DeclContext *Ctxt = DC; Ctxt; Ctxt = Ctxt->getParent()) {
        if (Ctxt->isFunctionOrMethod()) {
          FunctionOrMethod = Ctxt;
          break;
        }
        const CXXRecordDecl *ParentDecl = dyn_cast<CXXRecordDecl>(Ctxt);
        if (ParentDecl && !ParentDecl->getDeclName()) {
          AnonStruct = ParentDecl;
          break;
        }
      }
      if (FunctionOrMethod) {
        // C++ [class.static.data]p5: A local class shall not have static data
        // members.
        Diag(D.getIdentifierLoc(),
             diag::err_static_data_member_not_allowed_in_local_class)
          << Name << RD->getDeclName() << RD->getTagKind();
      } else if (AnonStruct) {
        // C++ [class.static.data]p4: Unnamed classes and classes contained
        // directly or indirectly within unnamed classes shall not contain
        // static data members.
        Diag(D.getIdentifierLoc(),
             diag::err_static_data_member_not_allowed_in_anon_struct)
          << Name << AnonStruct->getTagKind();
        Invalid = true;
      } else if (RD->isUnion()) {
        // C++98 [class.union]p1: If a union contains a static data member,
        // the program is ill-formed. C++11 drops this restriction.
        Diag(D.getIdentifierLoc(),
             getLangOpts().CPlusPlus11
               ? diag::warn_cxx98_compat_static_data_member_in_union
               : diag::ext_static_data_member_in_union) << Name;
      }
    }
  }

  // Match up the template parameter lists with the scope specifier, then
  // determine whether we have a template or a template specialization.
  bool InvalidScope = false;
  TemplateParams = MatchTemplateParametersToScopeSpecifier(
      D.getDeclSpec().getBeginLoc(), D.getIdentifierLoc(),
      D.getCXXScopeSpec(),
      D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId
          ? D.getName().TemplateId
          : nullptr,
      TemplateParamLists,
      /*never a friend*/ false, IsMemberSpecialization, InvalidScope);
  Invalid |= InvalidScope;

  if (TemplateParams) {
    if (!TemplateParams->size() &&
        D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
      // There is an extraneous 'template<>' for this variable. Complain
      // about it, but allow the declaration of the variable.
      Diag(TemplateParams->getTemplateLoc(),
           diag::err_template_variable_noparams)
        << II
        << SourceRange(TemplateParams->getTemplateLoc(),
                       TemplateParams->getRAngleLoc());
      TemplateParams = nullptr;
    } else {
      // Check that we can declare a template here.
      if (CheckTemplateDeclScope(S, TemplateParams))
        return nullptr;

      if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
        // This is an explicit specialization or a partial specialization.
        IsVariableTemplateSpecialization = true;
        IsPartialSpecialization = TemplateParams->size() > 0;
      } else { // if (TemplateParams->size() > 0)
        // This is a template declaration.
        IsVariableTemplate = true;

        // Only C++1y supports variable templates (N3651).
        Diag(D.getIdentifierLoc(),
             getLangOpts().CPlusPlus14
                 ? diag::warn_cxx11_compat_variable_template
                 : diag::ext_variable_template);
      }
    }
  } else {
    // Check that we can declare a member specialization here.
    if (!TemplateParamLists.empty() && IsMemberSpecialization &&
        CheckTemplateDeclScope(S, TemplateParamLists.back()))
      return nullptr;
    assert((Invalid ||((void)0)
            D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) &&((void)0)
           "should have a 'template<>' for this decl")((void)0);
  }

  if (IsVariableTemplateSpecialization) {
    SourceLocation TemplateKWLoc =
        TemplateParamLists.size() > 0
            ? TemplateParamLists[0]->getTemplateLoc()
            : SourceLocation();
    DeclResult Res = ActOnVarTemplateSpecialization(
        S, D, TInfo, TemplateKWLoc, TemplateParams, SC,
        IsPartialSpecialization);
    if (Res.isInvalid())
      return nullptr;
    NewVD = cast<VarDecl>(Res.get());
    AddToScope = false;
  } else if (D.isDecompositionDeclarator()) {
    NewVD = DecompositionDecl::Create(Context, DC, D.getBeginLoc(),
                                      D.getIdentifierLoc(), R, TInfo, SC,
                                      Bindings);
  } else
    NewVD = VarDecl::Create(Context, DC, D.getBeginLoc(),
                            D.getIdentifierLoc(), II, R, TInfo, SC);

  // If this is supposed to be a variable template, create it as such.
  if (IsVariableTemplate) {
    NewTemplate =
        VarTemplateDecl::Create(Context, DC, D.getIdentifierLoc(), Name,
                                TemplateParams, NewVD);
    NewVD->setDescribedVarTemplate(NewTemplate);
  }

  // If this decl has an auto type in need of deduction, make a note of the
  // Decl so we can diagnose uses of it in its own initializer.
  if (R->getContainedDeducedType())
    ParsingInitForAutoVars.insert(NewVD);

  if (D.isInvalidType() || Invalid) {
    NewVD->setInvalidDecl();
    if (NewTemplate)
      NewTemplate->setInvalidDecl();
  }

  SetNestedNameSpecifier(*this, NewVD, D);

  // If we have any template parameter lists that don't directly belong to
  // the variable (matching the scope specifier), store them.
  unsigned VDTemplateParamLists = TemplateParams ? 1 : 0;
  if (TemplateParamLists.size() > VDTemplateParamLists)
    NewVD->setTemplateParameterListsInfo(
        Context, TemplateParamLists.drop_back(VDTemplateParamLists));
}

if (D.getDeclSpec().isInlineSpecified()) {
  if (!getLangOpts().CPlusPlus) {
    Diag(D.getDeclSpec().getInlineSpecLoc(), diag::err_inline_non_function)
        << 0;
  } else if (CurContext->isFunctionOrMethod()) {
    // 'inline' is not allowed on block scope variable declaration.
    Diag(D.getDeclSpec().getInlineSpecLoc(),
         diag::err_inline_declaration_block_scope) << Name
      << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
  } else {
    Diag(D.getDeclSpec().getInlineSpecLoc(),
         getLangOpts().CPlusPlus17 ? diag::warn_cxx14_compat_inline_variable
                                   : diag::ext_inline_variable);
    NewVD->setInlineSpecified();
  }
}

// Set the lexical context. If the declarator has a C++ scope specifier, the
// lexical context will be different from the semantic context.
NewVD->setLexicalDeclContext(CurContext);
if (NewTemplate)
  NewTemplate->setLexicalDeclContext(CurContext);

if (IsLocalExternDecl) {
  if (D.isDecompositionDeclarator())
    for (auto *B : Bindings)
      B->setLocalExternDecl();
  else
    NewVD->setLocalExternDecl();
}

bool EmitTLSUnsupportedError = false;
if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec()) {
  // C++11 [dcl.stc]p4:
  //   When thread_local is applied to a variable of block scope the
  //   storage-class-specifier static is implied if it does not appear
  //   explicitly.
  // Core issue: 'static' is not implied if the variable is declared
  //   'extern'.
  if (NewVD->hasLocalStorage() &&
      (SCSpec != DeclSpec::SCS_unspecified ||
       TSCS != DeclSpec::TSCS_thread_local ||
       !DC->isFunctionOrMethod()))
    Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
         diag::err_thread_non_global)
      << DeclSpec::getSpecifierName(TSCS);
  else if (!Context.getTargetInfo().isTLSSupported()) {
    if (getLangOpts().CUDA || getLangOpts().OpenMPIsDevice ||
        getLangOpts().SYCLIsDevice) {
      // Postpone error emission until we've collected attributes required to
      // figure out whether it's a host or device variable and whether the
      // error should be ignored.
      EmitTLSUnsupportedError = true;
      // We still need to mark the variable as TLS so it shows up in AST with
      // proper storage class for other tools to use even if we're not going
      // to emit any code for it.
      NewVD->setTSCSpec(TSCS);
    } else
      Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
           diag::err_thread_unsupported);
  } else
    NewVD->setTSCSpec(TSCS);
}

switch (D.getDeclSpec().getConstexprSpecifier()) {
case ConstexprSpecKind::Unspecified:
  break;

case ConstexprSpecKind::Consteval:
  Diag(D.getDeclSpec().getConstexprSpecLoc(),
       diag::err_constexpr_wrong_decl_kind)
      << static_cast<int>(D.getDeclSpec().getConstexprSpecifier());
  LLVM_FALLTHROUGH[[gnu::fallthrough]];

case ConstexprSpecKind::Constexpr:
  NewVD->setConstexpr(true);
  // C++1z [dcl.spec.constexpr]p1:
  //   A static data member declared with the constexpr specifier is
  //   implicitly an inline variable.
  if (NewVD->isStaticDataMember() &&
      (getLangOpts().CPlusPlus17 ||
       Context.getTargetInfo().getCXXABI().isMicrosoft()))
    NewVD->setImplicitlyInline();
  break;

case ConstexprSpecKind::Constinit:
  if (!NewVD->hasGlobalStorage())
    Diag(D.getDeclSpec().getConstexprSpecLoc(),
         diag::err_constinit_local_variable);
  else
    NewVD->addAttr(ConstInitAttr::Create(
        Context, D.getDeclSpec().getConstexprSpecLoc(),
        AttributeCommonInfo::AS_Keyword, ConstInitAttr::Keyword_constinit));
  break;
}

// C99 6.7.4p3
//   An inline definition of a function with external linkage shall
//   not contain a definition of a modifiable object with static or
//   thread storage duration...
// We only apply this when the function is required to be defined
// elsewhere, i.e. when the function is not 'extern inline'.  Note
// that a local variable with thread storage duration still has to
// be marked 'static'.  Also note that it's possible to get these
// semantics in C++ using __attribute__((gnu_inline)).
if (SC == SC_Static && S->getFnParent() != nullptr &&
    !NewVD->getType().isConstQualified()) {
  FunctionDecl *CurFD = getCurFunctionDecl();
  if (CurFD && isFunctionDefinitionDiscarded(*this, CurFD)) {
    Diag(D.getDeclSpec().getStorageClassSpecLoc(),
         diag::warn_static_local_in_extern_inline);
    MaybeSuggestAddingStaticToDecl(CurFD);
  }
}

if (D.getDeclSpec().isModulePrivateSpecified()) {
  if (IsVariableTemplateSpecialization)
    Diag(NewVD->getLocation(), diag::err_module_private_specialization)
        << (IsPartialSpecialization ? 1 : 0)
        << FixItHint::CreateRemoval(
               D.getDeclSpec().getModulePrivateSpecLoc());
  else if (IsMemberSpecialization)
    Diag(NewVD->getLocation(), diag::err_module_private_specialization)
      << 2
      << FixItHint::CreateRemoval(D.getDeclSpec().getModulePrivateSpecLoc());
  else if (NewVD->hasLocalStorage())
    Diag(NewVD->getLocation(), diag::err_module_private_local)
        << 0 << NewVD
        << SourceRange(D.getDeclSpec().getModulePrivateSpecLoc())
        << FixItHint::CreateRemoval(
               D.getDeclSpec().getModulePrivateSpecLoc());
  else {
    NewVD->setModulePrivate();
    if (NewTemplate)
      NewTemplate->setModulePrivate();
    for (auto *B : Bindings)
      B->setModulePrivate();
  }
}

if (getLangOpts().OpenCL) {
  deduceOpenCLAddressSpace(NewVD);

  DeclSpec::TSCS TSC = D.getDeclSpec().getThreadStorageClassSpec();
  if (TSC != TSCS_unspecified) {
    bool IsCXX = getLangOpts().OpenCLCPlusPlus;
    Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
         diag::err_opencl_unknown_type_specifier)
        << IsCXX << getLangOpts().getOpenCLVersionTuple().getAsString()
        << DeclSpec::getSpecifierName(TSC) << 1;
    NewVD->setInvalidDecl();
  }
}

// Handle attributes prior to checking for duplicates in MergeVarDecl
ProcessDeclAttributes(S, NewVD, D);

// FIXME: This is probably the wrong location to be doing this and we should
// probably be doing this for more attributes (especially for function
// pointer attributes such as format, warn_unused_result, etc.). Ideally
// the code to copy attributes would be generated by TableGen.
if (R->isFunctionPointerType())
  if (const auto *TT = R->getAs<TypedefType>())
    copyAttrFromTypedefToDecl<AllocSizeAttr>(*this, NewVD, TT);

if (getLangOpts().CUDA || getLangOpts().OpenMPIsDevice ||
    getLangOpts().SYCLIsDevice) {
  if (EmitTLSUnsupportedError &&
      ((getLangOpts().CUDA && DeclAttrsMatchCUDAMode(getLangOpts(), NewVD)) ||
       (getLangOpts().OpenMPIsDevice &&
        OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(NewVD))))
    Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
         diag::err_thread_unsupported);

  if (EmitTLSUnsupportedError &&
      (LangOpts.SYCLIsDevice || (LangOpts.OpenMP && LangOpts.OpenMPIsDevice)))
    targetDiag(D.getIdentifierLoc(), diag::err_thread_unsupported);
  // CUDA B.2.5: "__shared__ and __constant__ variables have implied static
  // storage [duration]."
  if (SC == SC_None && S->getFnParent() != nullptr &&
      (NewVD->hasAttr<CUDASharedAttr>() ||
       NewVD->hasAttr<CUDAConstantAttr>())) {
    NewVD->setStorageClass(SC_Static);
  }
}

// Ensure that dllimport globals without explicit storage class are treated as
// extern. The storage class is set above using parsed attributes. Now we can
// check the VarDecl itself.
assert(!NewVD->hasAttr<DLLImportAttr>() ||((void)0)
       NewVD->getAttr<DLLImportAttr>()->isInherited() ||((void)0)
       NewVD->isStaticDataMember() || NewVD->getStorageClass() != SC_None)((void)0);

// In auto-retain/release, infer strong retension for variables of
// retainable type.
if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewVD))
  NewVD->setInvalidDecl();

// Handle GNU asm-label extension (encoded as an attribute).
if (Expr *E = (Expr*)D.getAsmLabel()) {
  // The parser guarantees this is a string.
  StringLiteral *SE = cast<StringLiteral>(E);
  StringRef Label = SE->getString();
  if (S->getFnParent() != nullptr) {
    switch (SC) {
    case SC_None:
    case SC_Auto:
      Diag(E->getExprLoc(), diag::warn_asm_label_on_auto_decl) << Label;
      break;
    case SC_Register:
      // Local Named register
      if (!Context.getTargetInfo().isValidGCCRegisterName(Label) &&
          DeclAttrsMatchCUDAMode(getLangOpts(), getCurFunctionDecl()))
        Diag(E->getExprLoc(), diag::err_asm_unknown_register_name) << Label;
      break;
    case SC_Static:
    case SC_Extern:
    case SC_PrivateExtern:
      break;
    }
  } else if (SC == SC_Register) {
    // Global Named register
    if (DeclAttrsMatchCUDAMode(getLangOpts(), NewVD)) {
      const auto &TI = Context.getTargetInfo();
      bool HasSizeMismatch;

      if (!TI.isValidGCCRegisterName(Label))
        Diag(E->getExprLoc(), diag::err_asm_unknown_register_name) << Label;
      else if (!TI.validateGlobalRegisterVariable(Label,
                                                  Context.getTypeSize(R),
                                                  HasSizeMismatch))
        Diag(E->getExprLoc(), diag::err_asm_invalid_global_var_reg) << Label;
      else if (HasSizeMismatch)
        Diag(E->getExprLoc(), diag::err_asm_register_size_mismatch) << Label;
    }

    if (!R->isIntegralType(Context) && !R->isPointerType()) {
      Diag(D.getBeginLoc(), diag::err_asm_bad_register_type);
      NewVD->setInvalidDecl(true);
    }
  }

  NewVD->addAttr(AsmLabelAttr::Create(Context, Label,
                                      /*IsLiteralLabel=*/true,
                                      SE->getStrTokenLoc(0)));
} else if (!ExtnameUndeclaredIdentifiers.empty()) {
  llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*>::iterator I =
    ExtnameUndeclaredIdentifiers.find(NewVD->getIdentifier());
  if (I != ExtnameUndeclaredIdentifiers.end()) {
    if (isDeclExternC(NewVD)) {
      NewVD->addAttr(I->second);
      ExtnameUndeclaredIdentifiers.erase(I);
    } else
      Diag(NewVD->getLocation(), diag::warn_redefine_extname_not_applied)
          << /*Variable*/1 << NewVD;
  }
}

// Find the shadowed declaration before filtering for scope.
NamedDecl *ShadowedDecl = D.getCXXScopeSpec().isEmpty()
                              ? getShadowedDeclaration(NewVD, Previous)
                              : nullptr;

// Don't consider existing declarations that are in a different
// scope and are out-of-semantic-context declarations (if the new
// declaration has linkage).
FilterLookupForScope(Previous, OriginalDC, S, shouldConsiderLinkage(NewVD),
                     D.getCXXScopeSpec().isNotEmpty() ||
                     IsMemberSpecialization ||
                     IsVariableTemplateSpecialization);

// Check whether the previous declaration is in the same block scope. This
// affects whether we merge types with it, per C++11 [dcl.array]p3.
if (getLangOpts().CPlusPlus &&
    NewVD->isLocalVarDecl() && NewVD->hasExternalStorage())
  NewVD->setPreviousDeclInSameBlockScope(
      Previous.isSingleResult() && !Previous.isShadowed() &&
      isDeclInScope(Previous.getFoundDecl(), OriginalDC, S, false));

if (!getLangOpts().CPlusPlus) {
  D.setRedeclaration(CheckVariableDeclaration(NewVD, Previous));
} else {
  // If this is an explicit specialization of a static data member, check it.
  if (IsMemberSpecialization && !NewVD->isInvalidDecl() &&
      CheckMemberSpecialization(NewVD, Previous))
    NewVD->setInvalidDecl();

  // Merge the decl with the existing one if appropriate.
  if (!Previous.empty()) {
    if (Previous.isSingleResult() &&
        isa<FieldDecl>(Previous.getFoundDecl()) &&
        D.getCXXScopeSpec().isSet()) {
      // The user tried to define a non-static data member
      // out-of-line (C++ [dcl.meaning]p1).
      Diag(NewVD->getLocation(), diag::err_nonstatic_member_out_of_line)
        << D.getCXXScopeSpec().getRange();
      Previous.clear();
      NewVD->setInvalidDecl();
    }
  } else if (D.getCXXScopeSpec().isSet()) {
    // No previous declaration in the qualifying scope.
    Diag(D.getIdentifierLoc(), diag::err_no_member)
      << Name << computeDeclContext(D.getCXXScopeSpec(), true)
      << D.getCXXScopeSpec().getRange();
    NewVD->setInvalidDecl();
  }

  if (!IsVariableTemplateSpecialization)
    D.setRedeclaration(CheckVariableDeclaration(NewVD, Previous));

  if (NewTemplate) {
    VarTemplateDecl *PrevVarTemplate =
        NewVD->getPreviousDecl()
            ? NewVD->getPreviousDecl()->getDescribedVarTemplate()
            : nullptr;

    // Check the template parameter list of this declaration, possibly
    // merging in the template parameter list from the previous variable
    // template declaration.
    if (CheckTemplateParameterList(
            TemplateParams,
            PrevVarTemplate ? PrevVarTemplate->getTemplateParameters()
                            : nullptr,
            (D.getCXXScopeSpec().isSet() && DC && DC->isRecord() &&
             DC->isDependentContext())
                ? TPC_ClassTemplateMember
                : TPC_VarTemplate))
      NewVD->setInvalidDecl();

    // If we are providing an explicit specialization of a static variable
    // template, make a note of that.
    if (PrevVarTemplate &&
        PrevVarTemplate->getInstantiatedFromMemberTemplate())
      PrevVarTemplate->setMemberSpecialization();
  }
}

// Diagnose shadowed variables iff this isn't a redeclaration.
if (ShadowedDecl && !D.isRedeclaration())
  CheckShadow(NewVD, ShadowedDecl, Previous);

ProcessPragmaWeak(S, NewVD);

// If this is the first declaration of an extern C variable, update
// the map of such variables.
if (NewVD->isFirstDecl() && !NewVD->isInvalidDecl() &&
    isIncompleteDeclExternC(*this, NewVD))
  RegisterLocallyScopedExternCDecl(NewVD, S);

if (getLangOpts().CPlusPlus && NewVD->isStaticLocal()) {
  MangleNumberingContext *MCtx;
  Decl *ManglingContextDecl;
  std::tie(MCtx, ManglingContextDecl) =
      getCurrentMangleNumberContext(NewVD->getDeclContext());
  if (MCtx) {
    Context.setManglingNumber(
        NewVD, MCtx->getManglingNumber(
                   NewVD, getMSManglingNumber(getLangOpts(), S)));
    Context.setStaticLocalNumber(NewVD, MCtx->getStaticLocalNumber(NewVD));
  }
}

// Special handling of variable named 'main'.
if (Name.getAsIdentifierInfo() && Name.getAsIdentifierInfo()->isStr("main") &&
    NewVD->getDeclContext()->getRedeclContext()->isTranslationUnit() &&
    !getLangOpts().Freestanding && !NewVD->getDescribedVarTemplate()) {

  // C++ [basic.start.main]p3
  // A program that declares a variable main at global scope is ill-formed.
  if (getLangOpts().CPlusPlus)
    Diag(D.getBeginLoc(), diag::err_main_global_variable);

  // In C, and external-linkage variable named main results in undefined
  // behavior.
  else if (NewVD->hasExternalFormalLinkage())
    Diag(D.getBeginLoc(), diag::warn_main_redefined);
}

if (D.isRedeclaration() && !Previous.empty()) {
  NamedDecl *Prev = Previous.getRepresentativeDecl();
  checkDLLAttributeRedeclaration(*this, Prev, NewVD, IsMemberSpecialization,
                                 D.isFunctionDefinition());
}

if (NewTemplate) {
  if (NewVD->isInvalidDecl())
    NewTemplate->setInvalidDecl();
  ActOnDocumentableDecl(NewTemplate);
  return NewTemplate;
}

if (IsMemberSpecialization && !NewVD->isInvalidDecl())
  CompleteMemberSpecialization(NewVD, Previous);

return NewVD;
7580}

7582/// Enum describing the %select options in diag::warn_decl_shadow.
7583enum ShadowedDeclKind {
SDK_Local,
SDK_Global,
SDK_StaticMember,
SDK_Field,
SDK_Typedef,
SDK_Using,
SDK_StructuredBinding
7591};

7593/// Determine what kind of declaration we're shadowing.
7594static ShadowedDeclKind computeShadowedDeclKind(const NamedDecl *ShadowedDecl,
                                              const DeclContext *OldDC) {
if (isa<TypeAliasDecl>(ShadowedDecl))
  return SDK_Using;
else if (isa<TypedefDecl>(ShadowedDecl))
  return SDK_Typedef;
else if (isa<BindingDecl>(ShadowedDecl))
  return SDK_StructuredBinding;
else if (isa<RecordDecl>(OldDC))
  return isa<FieldDecl>(ShadowedDecl) ? SDK_Field : SDK_StaticMember;

return OldDC->isFileContext() ? SDK_Global : SDK_Local;
7606}

7608/// Return the location of the capture if the given lambda captures the given
7609/// variable \p VD, or an invalid source location otherwise.
7610static SourceLocation getCaptureLocation(const LambdaScopeInfo *LSI,
                                       const VarDecl *VD) {
for (const Capture &Capture : LSI->Captures) {
  if (Capture.isVariableCapture() && Capture.getVariable() == VD)
    return Capture.getLocation();
}
return SourceLocation();
7617}

7619static bool shouldWarnIfShadowedDecl(const DiagnosticsEngine &Diags,
                                   const LookupResult &R) {
// Only diagnose if we're shadowing an unambiguous field or variable.
if (R.getResultKind() != LookupResult::Found)
  return false;

// Return false if warning is ignored.
return !Diags.isIgnored(diag::warn_decl_shadow, R.getNameLoc());
7627}

7629/// Return the declaration shadowed by the given variable \p D, or null
7630/// if it doesn't shadow any declaration or shadowing warnings are disabled.
7631NamedDecl *Sema::getShadowedDeclaration(const VarDecl *D,
                                      const LookupResult &R) {
if (!shouldWarnIfShadowedDecl(Diags, R))
  return nullptr;

// Don't diagnose declarations at file scope.
if (D->hasGlobalStorage())
  return nullptr;

NamedDecl *ShadowedDecl = R.getFoundDecl();
return isa<VarDecl, FieldDecl, BindingDecl>(ShadowedDecl) ? ShadowedDecl
                                                          : nullptr;
7643}

7645/// Return the declaration shadowed by the given typedef \p D, or null
7646/// if it doesn't shadow any declaration or shadowing warnings are disabled.
7647NamedDecl *Sema::getShadowedDeclaration(const TypedefNameDecl *D,
                                      const LookupResult &R) {
// Don't warn if typedef declaration is part of a class
if (D->getDeclContext()->isRecord())
  return nullptr;

if (!shouldWarnIfShadowedDecl(Diags, R))
  return nullptr;

NamedDecl *ShadowedDecl = R.getFoundDecl();
return isa<TypedefNameDecl>(ShadowedDecl) ? ShadowedDecl : nullptr;
7658}

7660/// Return the declaration shadowed by the given variable \p D, or null
7661/// if it doesn't shadow any declaration or shadowing warnings are disabled.
7662NamedDecl *Sema::getShadowedDeclaration(const BindingDecl *D,
                                      const LookupResult &R) {
if (!shouldWarnIfShadowedDecl(Diags, R))
  return nullptr;

NamedDecl *ShadowedDecl = R.getFoundDecl();
return isa<VarDecl, FieldDecl, BindingDecl>(ShadowedDecl) ? ShadowedDecl
                                                          : nullptr;
7670}

7672/// Diagnose variable or built-in function shadowing.  Implements
7673/// -Wshadow.
7674///
7675/// This method is called whenever a VarDecl is added to a "useful"
7676/// scope.
7677///
7678/// \param ShadowedDecl the declaration that is shadowed by the given variable
7679/// \param R the lookup of the name
7680///
7681void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
                     const LookupResult &R) {
DeclContext *NewDC = D->getDeclContext();

if (FieldDecl *FD = dyn_cast<FieldDecl>(ShadowedDecl)) {
  // Fields are not shadowed by variables in C++ static methods.
  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewDC))
    if (MD->isStatic())
      return;

  // Fields shadowed by constructor parameters are a special case. Usually
  // the constructor initializes the field with the parameter.
  if (isa<CXXConstructorDecl>(NewDC))
    if (const auto PVD = dyn_cast<ParmVarDecl>(D)) {
      // Remember that this was shadowed so we can either warn about its
      // modification or its existence depending on warning settings.
      ShadowingDecls.insert({PVD->getCanonicalDecl(), FD});
      return;
    }
}

if (VarDecl *shadowedVar = dyn_cast<VarDecl>(ShadowedDecl))
  if (shadowedVar->isExternC()) {
    // For shadowing external vars, make sure that we point to the global
    // declaration, not a locally scoped extern declaration.
    for (auto I : shadowedVar->redecls())
      if (I->isFileVarDecl()) {
        ShadowedDecl = I;
        break;
      }
  }

DeclContext *OldDC = ShadowedDecl->getDeclContext()->getRedeclContext();

unsigned WarningDiag = diag::warn_decl_shadow;
SourceLocation CaptureLoc;
if (isa<VarDecl>(D) && isa<VarDecl>(ShadowedDecl) && NewDC &&
    isa<CXXMethodDecl>(NewDC)) {
  if (const auto *RD = dyn_cast<CXXRecordDecl>(NewDC->getParent())) {
    if (RD->isLambda() && OldDC->Encloses(NewDC->getLexicalParent())) {
      if (RD->getLambdaCaptureDefault() == LCD_None) {
        // Try to avoid warnings for lambdas with an explicit capture list.
        const auto *LSI = cast<LambdaScopeInfo>(getCurFunction());
        // Warn only when the lambda captures the shadowed decl explicitly.
        CaptureLoc = getCaptureLocation(LSI, cast<VarDecl>(ShadowedDecl));
        if (CaptureLoc.isInvalid())
          WarningDiag = diag::warn_decl_shadow_uncaptured_local;
      } else {
        // Remember that this was shadowed so we can avoid the warning if the
        // shadowed decl isn't captured and the warning settings allow it.
        cast<LambdaScopeInfo>(getCurFunction())
            ->ShadowingDecls.push_back(
                {cast<VarDecl>(D), cast<VarDecl>(ShadowedDecl)});
        return;
      }
    }

    if (cast<VarDecl>(ShadowedDecl)->hasLocalStorage()) {
      // A variable can't shadow a local variable in an enclosing scope, if
      // they are separated by a non-capturing declaration context.
      for (DeclContext *ParentDC = NewDC;
           ParentDC && !ParentDC->Equals(OldDC);
           ParentDC = getLambdaAwareParentOfDeclContext(ParentDC)) {
        // Only block literals, captured statements, and lambda expressions
        // can capture; other scopes don't.
        if (!isa<BlockDecl>(ParentDC) && !isa<CapturedDecl>(ParentDC) &&
            !isLambdaCallOperator(ParentDC)) {
          return;
        }
      }
    }
  }
}

// Only warn about certain kinds of shadowing for class members.
if (NewDC && NewDC->isRecord()) {
  // In particular, don't warn about shadowing non-class members.
  if (!OldDC->isRecord())
    return;

  // TODO: should we warn about static data members shadowing
  // static data members from base classes?

  // TODO: don't diagnose for inaccessible shadowed members.
  // This is hard to do perfectly because we might friend the
  // shadowing context, but that's just a false negative.
}


DeclarationName Name = R.getLookupName();

// Emit warning and note.
if (getSourceManager().isInSystemMacro(R.getNameLoc()))
  return;
ShadowedDeclKind Kind = computeShadowedDeclKind(ShadowedDecl, OldDC);
Diag(R.getNameLoc(), WarningDiag) << Name << Kind << OldDC;
if (!CaptureLoc.isInvalid())
  Diag(CaptureLoc, diag::note_var_explicitly_captured_here)
      << Name << /*explicitly*/ 1;
Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
7781}

7783/// Diagnose shadowing for variables shadowed in the lambda record \p LambdaRD
7784/// when these variables are captured by the lambda.
7785void Sema::DiagnoseShadowingLambdaDecls(const LambdaScopeInfo *LSI) {
for (const auto &Shadow : LSI->ShadowingDecls) {
  const VarDecl *ShadowedDecl = Shadow.ShadowedDecl;
  // Try to avoid the warning when the shadowed decl isn't captured.
  SourceLocation CaptureLoc = getCaptureLocation(LSI, ShadowedDecl);
  const DeclContext *OldDC = ShadowedDecl->getDeclContext();
  Diag(Shadow.VD->getLocation(), CaptureLoc.isInvalid()
                                     ? diag::warn_decl_shadow_uncaptured_local
                                     : diag::warn_decl_shadow)
      << Shadow.VD->getDeclName()
      << computeShadowedDeclKind(ShadowedDecl, OldDC) << OldDC;
  if (!CaptureLoc.isInvalid())
    Diag(CaptureLoc, diag::note_var_explicitly_captured_here)
        << Shadow.VD->getDeclName() << /*explicitly*/ 0;
  Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
}
7801}

7803/// Check -Wshadow without the advantage of a previous lookup.
7804void Sema::CheckShadow(Scope *S, VarDecl *D) {
if (Diags.isIgnored(diag::warn_decl_shadow, D->getLocation()))
  return;

LookupResult R(*this, D->getDeclName(), D->getLocation(),
               Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
LookupName(R, S);
if (NamedDecl *ShadowedDecl = getShadowedDeclaration(D, R))
  CheckShadow(D, ShadowedDecl, R);
7813}

7815/// Check if 'E', which is an expression that is about to be modified, refers
7816/// to a constructor parameter that shadows a field.
7817void Sema::CheckShadowingDeclModification(Expr *E, SourceLocation Loc) {
// Quickly ignore expressions that can't be shadowing ctor parameters.
if (!getLangOpts().CPlusPlus || ShadowingDecls.empty())
  return;
E = E->IgnoreParenImpCasts();
auto *DRE = dyn_cast<DeclRefExpr>(E);
if (!DRE)
  return;
const NamedDecl *D = cast<NamedDecl>(DRE->getDecl()->getCanonicalDecl());
auto I = ShadowingDecls.find(D);
if (I == ShadowingDecls.end())
  return;
const NamedDecl *ShadowedDecl = I->second;
const DeclContext *OldDC = ShadowedDecl->getDeclContext();
Diag(Loc, diag::warn_modifying_shadowing_decl) << D << OldDC;
Diag(D->getLocation(), diag::note_var_declared_here) << D;
Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);

// Avoid issuing multiple warnings about the same decl.
ShadowingDecls.erase(I);
7837}

7839/// Check for conflict between this global or extern "C" declaration and
7840/// previous global or extern "C" declarations. This is only used in C++.
7841template<typename T>
7842static bool checkGlobalOrExternCConflict(
  Sema &S, const T *ND, bool IsGlobal, LookupResult &Previous) {
assert(S.getLangOpts().CPlusPlus && "only C++ has extern \"C\"")((void)0);
NamedDecl *Prev = S.findLocallyScopedExternCDecl(ND->getDeclName());

if (!Prev && IsGlobal && !isIncompleteDeclExternC(S, ND)) {
  // The common case: this global doesn't conflict with any extern "C"
  // declaration.
  return false;
}

if (Prev) {
  if (!IsGlobal || isIncompleteDeclExternC(S, ND)) {
    // Both the old and new declarations have C language linkage. This is a
    // redeclaration.
    Previous.clear();
    Previous.addDecl(Prev);
    return true;
  }

  // This is a global, non-extern "C" declaration, and there is a previous
  // non-global extern "C" declaration. Diagnose if this is a variable
  // declaration.
  if (!isa<VarDecl>(ND))
    return false;
} else {
  // The declaration is extern "C". Check for any declaration in the
  // translation unit which might conflict.
  if (IsGlobal) {
    // We have already performed the lookup into the translation unit.
    IsGlobal = false;
    for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
         I != E; ++I) {
      if (isa<VarDecl>(*I)) {
        Prev = *I;
        break;
      }
    }
  } else {
    DeclContext::lookup_result R =
        S.Context.getTranslationUnitDecl()->lookup(ND->getDeclName());
    for (DeclContext::lookup_result::iterator I = R.begin(), E = R.end();
         I != E; ++I) {
      if (isa<VarDecl>(*I)) {
        Prev = *I;
        break;
      }
      // FIXME: If we have any other entity with this name in global scope,
      // the declaration is ill-formed, but that is a defect: it breaks the
      // 'stat' hack, for instance. Only variables can have mangled name
      // clashes with extern "C" declarations, so only they deserve a
      // diagnostic.
    }
  }

  if (!Prev)
    return false;
}

// Use the first declaration's location to ensure we point at something which
// is lexically inside an extern "C" linkage-spec.
assert(Prev && "should have found a previous declaration to diagnose")((void)0);
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(Prev))
  Prev = FD->getFirstDecl();
else
  Prev = cast<VarDecl>(Prev)->getFirstDecl();

S.Diag(ND->getLocation(), diag::err_extern_c_global_conflict)
  << IsGlobal << ND;
S.Diag(Prev->getLocation(), diag::note_extern_c_global_conflict)
  << IsGlobal;
return false;
7914}

7916/// Apply special rules for handling extern "C" declarations. Returns \c true
7917/// if we have found that this is a redeclaration of some prior entity.
7918///
7919/// Per C++ [dcl.link]p6:
7920///   Two declarations [for a function or variable] with C language linkage
7921///   with the same name that appear in different scopes refer to the same
7922///   [entity]. An entity with C language linkage shall not be declared with
7923///   the same name as an entity in global scope.
7924template<typename T>
7925static bool checkForConflictWithNonVisibleExternC(Sema &S, const T *ND,
                                                LookupResult &Previous) {
if (!S.getLangOpts().CPlusPlus) {
  // In C, when declaring a global variable, look for a corresponding 'extern'
  // variable declared in function scope. We don't need this in C++, because
  // we find local extern decls in the surrounding file-scope DeclContext.
  if (ND->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
    if (NamedDecl *Prev = S.findLocallyScopedExternCDecl(ND->getDeclName())) {
      Previous.clear();
      Previous.addDecl(Prev);
      return true;
    }
  }
  return false;
}

// A declaration in the translation unit can conflict with an extern "C"
// declaration.
if (ND->getDeclContext()->getRedeclContext()->isTranslationUnit())
  return checkGlobalOrExternCConflict(S, ND, /*IsGlobal*/true, Previous);

// An extern "C" declaration can conflict with a declaration in the
// translation unit or can be a redeclaration of an extern "C" declaration
// in another scope.
if (isIncompleteDeclExternC(S,ND))
  return checkGlobalOrExternCConflict(S, ND, /*IsGlobal*/false, Previous);

// Neither global nor extern "C": nothing to do.
return false;
7954}

7956void Sema::CheckVariableDeclarationType(VarDecl *NewVD) {
// If the decl is already known invalid, don't check it.
if (NewVD->isInvalidDecl())
  return;

QualType T = NewVD->getType();

// Defer checking an 'auto' type until its initializer is attached.
if (T->isUndeducedType())
  return;

if (NewVD->hasAttrs())
  CheckAlignasUnderalignment(NewVD);

if (T->isObjCObjectType()) {
  Diag(NewVD->getLocation(), diag::err_statically_allocated_object)
    << FixItHint::CreateInsertion(NewVD->getLocation(), "*");
  T = Context.getObjCObjectPointerType(T);
  NewVD->setType(T);
}

// Emit an error if an address space was applied to decl with local storage.
// This includes arrays of objects with address space qualifiers, but not
// automatic variables that point to other address spaces.
// ISO/IEC TR 18037 S5.1.2
if (!getLangOpts().OpenCL && NewVD->hasLocalStorage() &&
    T.getAddressSpace() != LangAS::Default) {
  Diag(NewVD->getLocation(), diag::err_as_qualified_auto_decl) << 0;
  NewVD->setInvalidDecl();
  return;
}

// OpenCL v1.2 s6.8 - The static qualifier is valid only in program
// scope.
if (getLangOpts().OpenCLVersion == 120 &&
    !getOpenCLOptions().isAvailableOption("cl_clang_storage_class_specifiers",
                                          getLangOpts()) &&
    NewVD->isStaticLocal()) {
  Diag(NewVD->getLocation(), diag::err_static_function_scope);
  NewVD->setInvalidDecl();
  return;
}

if (getLangOpts().OpenCL) {
  if (!diagnoseOpenCLTypes(*this, NewVD))
    return;

  // OpenCL v2.0 s6.12.5 - The __block storage type is not supported.
  if (NewVD->hasAttr<BlocksAttr>()) {
    Diag(NewVD->getLocation(), diag::err_opencl_block_storage_type);
    return;
  }

  if (T->isBlockPointerType()) {
    // OpenCL v2.0 s6.12.5 - Any block declaration must be const qualified and
    // can't use 'extern' storage class.
    if (!T.isConstQualified()) {
      Diag(NewVD->getLocation(), diag::err_opencl_invalid_block_declaration)
          << 0 /*const*/;
      NewVD->setInvalidDecl();
      return;
    }
    if (NewVD->hasExternalStorage()) {
      Diag(NewVD->getLocation(), diag::err_opencl_extern_block_declaration);
      NewVD->setInvalidDecl();
      return;
    }
  }

  // FIXME: Adding local AS in C++ for OpenCL might make sense.
  if (NewVD->isFileVarDecl() || NewVD->isStaticLocal() ||
      NewVD->hasExternalStorage()) {
    if (!T->isSamplerT() && !T->isDependentType() &&
        !(T.getAddressSpace() == LangAS::opencl_constant ||
          (T.getAddressSpace() == LangAS::opencl_global &&
           getOpenCLOptions().areProgramScopeVariablesSupported(
               getLangOpts())))) {
      int Scope = NewVD->isStaticLocal() | NewVD->hasExternalStorage() << 1;
      if (getOpenCLOptions().areProgramScopeVariablesSupported(getLangOpts()))
        Diag(NewVD->getLocation(), diag::err_opencl_global_invalid_addr_space)
            << Scope << "global or constant";
      else
        Diag(NewVD->getLocation(), diag::err_opencl_global_invalid_addr_space)
            << Scope << "constant";
      NewVD->setInvalidDecl();
      return;
    }
  } else {
    if (T.getAddressSpace() == LangAS::opencl_global) {
      Diag(NewVD->getLocation(), diag::err_opencl_function_variable)
          << 1 /*is any function*/ << "global";
      NewVD->setInvalidDecl();
      return;
    }
    if (T.getAddressSpace() == LangAS::opencl_constant ||
        T.getAddressSpace() == LangAS::opencl_local) {
      FunctionDecl *FD = getCurFunctionDecl();
      // OpenCL v1.1 s6.5.2 and s6.5.3: no local or constant variables
      // in functions.
      if (FD && !FD->hasAttr<OpenCLKernelAttr>()) {
        if (T.getAddressSpace() == LangAS::opencl_constant)
          Diag(NewVD->getLocation(), diag::err_opencl_function_variable)
              << 0 /*non-kernel only*/ << "constant";
        else
          Diag(NewVD->getLocation(), diag::err_opencl_function_variable)
              << 0 /*non-kernel only*/ << "local";
        NewVD->setInvalidDecl();
        return;
      }
      // OpenCL v2.0 s6.5.2 and s6.5.3: local and constant variables must be
      // in the outermost scope of a kernel function.
      if (FD && FD->hasAttr<OpenCLKernelAttr>()) {
        if (!getCurScope()->isFunctionScope()) {
          if (T.getAddressSpace() == LangAS::opencl_constant)
            Diag(NewVD->getLocation(), diag::err_opencl_addrspace_scope)
                << "constant";
          else
            Diag(NewVD->getLocation(), diag::err_opencl_addrspace_scope)
                << "local";
          NewVD->setInvalidDecl();
          return;
        }
      }
    } else if (T.getAddressSpace() != LangAS::opencl_private &&
               // If we are parsing a template we didn't deduce an addr
               // space yet.
               T.getAddressSpace() != LangAS::Default) {
      // Do not allow other address spaces on automatic variable.
      Diag(NewVD->getLocation(), diag::err_as_qualified_auto_decl) << 1;
      NewVD->setInvalidDecl();
      return;
    }
  }
}

if (NewVD->hasLocalStorage() && T.isObjCGCWeak()
    && !NewVD->hasAttr<BlocksAttr>()) {
  if (getLangOpts().getGC() != LangOptions::NonGC)
    Diag(NewVD->getLocation(), diag::warn_gc_attribute_weak_on_local);
  else {
    assert(!getLangOpts().ObjCAutoRefCount)((void)0);
    Diag(NewVD->getLocation(), diag::warn_attribute_weak_on_local);
  }
}

bool isVM = T->isVariablyModifiedType();
if (isVM || NewVD->hasAttr<CleanupAttr>() ||
    NewVD->hasAttr<BlocksAttr>())
  setFunctionHasBranchProtectedScope();

if ((isVM && NewVD->hasLinkage()) ||
    (T->isVariableArrayType() && NewVD->hasGlobalStorage())) {
  bool SizeIsNegative;
  llvm::APSInt Oversized;
  TypeSourceInfo *FixedTInfo = TryToFixInvalidVariablyModifiedTypeSourceInfo(
      NewVD->getTypeSourceInfo(), Context, SizeIsNegative, Oversized);
  QualType FixedT;
  if (FixedTInfo &&  T == NewVD->getTypeSourceInfo()->getType())
    FixedT = FixedTInfo->getType();
  else if (FixedTInfo) {
    // Type and type-as-written are canonically different. We need to fix up
    // both types separately.
    FixedT = TryToFixInvalidVariablyModifiedType(T, Context, SizeIsNegative,
                                                 Oversized);
  }
  if ((!FixedTInfo || FixedT.isNull()) && T->isVariableArrayType()) {
    const VariableArrayType *VAT = Context.getAsVariableArrayType(T);
    // FIXME: This won't give the correct result for
    // int a[10][n];
    SourceRange SizeRange = VAT->getSizeExpr()->getSourceRange();

    if (NewVD->isFileVarDecl())
      Diag(NewVD->getLocation(), diag::err_vla_decl_in_file_scope)
      << SizeRange;
    else if (NewVD->isStaticLocal())
      Diag(NewVD->getLocation(), diag::err_vla_decl_has_static_storage)
      << SizeRange;
    else
      Diag(NewVD->getLocation(), diag::err_vla_decl_has_extern_linkage)
      << SizeRange;
    NewVD->setInvalidDecl();
    return;
  }

  if (!FixedTInfo) {
    if (NewVD->isFileVarDecl())
      Diag(NewVD->getLocation(), diag::err_vm_decl_in_file_scope);
    else
      Diag(NewVD->getLocation(), diag::err_vm_decl_has_extern_linkage);
    NewVD->setInvalidDecl();
    return;
  }

  Diag(NewVD->getLocation(), diag::ext_vla_folded_to_constant);
  NewVD->setType(FixedT);
  NewVD->setTypeSourceInfo(FixedTInfo);
}

if (T->isVoidType()) {
  // C++98 [dcl.stc]p5: The extern specifier can be applied only to the names
  //                    of objects and functions.
  if (NewVD->isThisDeclarationADefinition() || getLangOpts().CPlusPlus) {
    Diag(NewVD->getLocation(), diag::err_typecheck_decl_incomplete_type)
      << T;
    NewVD->setInvalidDecl();
    return;
  }
}

if (!NewVD->hasLocalStorage() && NewVD->hasAttr<BlocksAttr>()) {
  Diag(NewVD->getLocation(), diag::err_block_on_nonlocal);
  NewVD->setInvalidDecl();
  return;
}

if (!NewVD->hasLocalStorage() && T->isSizelessType()) {
  Diag(NewVD->getLocation(), diag::err_sizeless_nonlocal) << T;
  NewVD->setInvalidDecl();
  return;
}

if (isVM && NewVD->hasAttr<BlocksAttr>()) {
  Diag(NewVD->getLocation(), diag::err_block_on_vm);
  NewVD->setInvalidDecl();
  return;
}

if (NewVD->isConstexpr() && !T->isDependentType() &&
    RequireLiteralType(NewVD->getLocation(), T,
                       diag::err_constexpr_var_non_literal)) {
  NewVD->setInvalidDecl();
  return;
}

// PPC MMA non-pointer types are not allowed as non-local variable types.
if (Context.getTargetInfo().getTriple().isPPC64() &&
    !NewVD->isLocalVarDecl() &&
    CheckPPCMMAType(T, NewVD->getLocation())) {
  NewVD->setInvalidDecl();
  return;
}
8197}

8199/// Perform semantic checking on a newly-created variable
8200/// declaration.
8201///
8202/// This routine performs all of the type-checking required for a
8203/// variable declaration once it has been built. It is used both to
8204/// check variables after they have been parsed and their declarators
8205/// have been translated into a declaration, and to check variables
8206/// that have been instantiated from a template.
8207///
8208/// Sets NewVD->isInvalidDecl() if an error was encountered.
8209///
8210/// Returns true if the variable declaration is a redeclaration.
8211bool Sema::CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous) {
CheckVariableDeclarationType(NewVD);

// If the decl is already known invalid, don't check it.
if (NewVD->isInvalidDecl())
  return false;

// If we did not find anything by this name, look for a non-visible
// extern "C" declaration with the same name.
if (Previous.empty() &&
    checkForConflictWithNonVisibleExternC(*this, NewVD, Previous))
  Previous.setShadowed();

if (!Previous.empty()) {
  MergeVarDecl(NewVD, Previous);
  return true;
}
return false;
8229}

8231/// AddOverriddenMethods - See if a method overrides any in the base classes,
8232/// and if so, check that it's a valid override and remember it.
8233bool Sema::AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD) {
llvm::SmallPtrSet<const CXXMethodDecl*, 4> Overridden;

// Look for methods in base classes that this method might override.
CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
                   /*DetectVirtual=*/false);
auto VisitBase = [&] (const CXXBaseSpecifier *Specifier, CXXBasePath &Path) {
  CXXRecordDecl *BaseRecord = Specifier->getType()->getAsCXXRecordDecl();
  DeclarationName Name = MD->getDeclName();

  if (Name.getNameKind() == DeclarationName::CXXDestructorName) {
    // We really want to find the base class destructor here.
    QualType T = Context.getTypeDeclType(BaseRecord);
    CanQualType CT = Context.getCanonicalType(T);
    Name = Context.DeclarationNames.getCXXDestructorName(CT);
  }

  for (NamedDecl *BaseND : BaseRecord->lookup(Name)) {
    CXXMethodDecl *BaseMD =
        dyn_cast<CXXMethodDecl>(BaseND->getCanonicalDecl());
    if (!BaseMD || !BaseMD->isVirtual() ||
        IsOverload(MD, BaseMD, /*UseMemberUsingDeclRules=*/false,
                   /*ConsiderCudaAttrs=*/true,
                   // C++2a [class.virtual]p2 does not consider requires
                   // clauses when overriding.
                   /*ConsiderRequiresClauses=*/false))
      continue;

    if (Overridden.insert(BaseMD).second) {
      MD->addOverriddenMethod(BaseMD);
      CheckOverridingFunctionReturnType(MD, BaseMD);
      CheckOverridingFunctionAttributes(MD, BaseMD);
      CheckOverridingFunctionExceptionSpec(MD, BaseMD);
      CheckIfOverriddenFunctionIsMarkedFinal(MD, BaseMD);
    }

    // A method can only override one function from each base class. We
    // don't track indirectly overridden methods from bases of bases.
    return true;
  }

  return false;
};

DC->lookupInBases(VisitBase, Paths);
return !Overridden.empty();
8279}

8281namespace {
// Struct for holding all of the extra arguments needed by
// DiagnoseInvalidRedeclaration to call Sema::ActOnFunctionDeclarator.
struct ActOnFDArgs {
  Scope *S;
  Declarator &D;
  MultiTemplateParamsArg TemplateParamLists;
  bool AddToScope;
};
8290} // end anonymous namespace

8292namespace {

8294// Callback to only accept typo corrections that have a non-zero edit distance.
8295// Also only accept corrections that have the same parent decl.
8296class DifferentNameValidatorCCC final : public CorrectionCandidateCallback {
public:
DifferentNameValidatorCCC(ASTContext &Context, FunctionDecl *TypoFD,
                          CXXRecordDecl *Parent)
    : Context(Context), OriginalFD(TypoFD),
      ExpectedParent(Parent ? Parent->getCanonicalDecl() : nullptr) {}

bool ValidateCandidate(const TypoCorrection &candidate) override {
  if (candidate.getEditDistance() == 0)
    return false;

  SmallVector<unsigned, 1> MismatchedParams;
  for (TypoCorrection::const_decl_iterator CDecl = candidate.begin(),
                                        CDeclEnd = candidate.end();
       CDecl != CDeclEnd; ++CDecl) {
    FunctionDecl *FD = dyn_cast<FunctionDecl>(*CDecl);

    if (FD && !FD->hasBody() &&
        hasSimilarParameters(Context, FD, OriginalFD, MismatchedParams)) {
      if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
        CXXRecordDecl *Parent = MD->getParent();
        if (Parent && Parent->getCanonicalDecl() == ExpectedParent)
          return true;
      } else if (!ExpectedParent) {
        return true;
      }
    }
  }

  return false;
}

std::unique_ptr<CorrectionCandidateCallback> clone() override {
  return std::make_unique<DifferentNameValidatorCCC>(*this);
}

private:
ASTContext &Context;
FunctionDecl *OriginalFD;
CXXRecordDecl *ExpectedParent;
8336};

8338} // end anonymous namespace

8340void Sema::MarkTypoCorrectedFunctionDefinition(const NamedDecl *F) {
TypoCorrectedFunctionDefinitions.insert(F);
8342}

8344/// Generate diagnostics for an invalid function redeclaration.
8345///
8346/// This routine handles generating the diagnostic messages for an invalid
8347/// function redeclaration, including finding possible similar declarations
8348/// or performing typo correction if there are no previous declarations with
8349/// the same name.
8350///
8351/// Returns a NamedDecl iff typo correction was performed and substituting in
8352/// the new declaration name does not cause new errors.
8353static NamedDecl *DiagnoseInvalidRedeclaration(
  Sema &SemaRef, LookupResult &Previous, FunctionDecl *NewFD,
  ActOnFDArgs &ExtraArgs, bool IsLocalFriend, Scope *S) {
DeclarationName Name = NewFD->getDeclName();
DeclContext *NewDC = NewFD->getDeclContext();
SmallVector<unsigned, 1> MismatchedParams;
SmallVector<std::pair<FunctionDecl *, unsigned>, 1> NearMatches;
TypoCorrection Correction;
bool IsDefinition = ExtraArgs.D.isFunctionDefinition();
unsigned DiagMsg =
  IsLocalFriend ? diag::err_no_matching_local_friend :
  NewFD->getFriendObjectKind() ? diag::err_qualified_friend_no_match :
  diag::err_member_decl_does_not_match;
LookupResult Prev(SemaRef, Name, NewFD->getLocation(),
                  IsLocalFriend ? Sema::LookupLocalFriendName
                                : Sema::LookupOrdinaryName,
                  Sema::ForVisibleRedeclaration);

NewFD->setInvalidDecl();
if (IsLocalFriend)
  SemaRef.LookupName(Prev, S);
else
  SemaRef.LookupQualifiedName(Prev, NewDC);
assert(!Prev.isAmbiguous() &&((void)0)
       "Cannot have an ambiguity in previous-declaration lookup")((void)0);
CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
DifferentNameValidatorCCC CCC(SemaRef.Context, NewFD,
                              MD ? MD->getParent() : nullptr);
if (!Prev.empty()) {
  for (LookupResult::iterator Func = Prev.begin(), FuncEnd = Prev.end();
       Func != FuncEnd; ++Func) {
    FunctionDecl *FD = dyn_cast<FunctionDecl>(*Func);
    if (FD &&
        hasSimilarParameters(SemaRef.Context, FD, NewFD, MismatchedParams)) {
      // Add 1 to the index so that 0 can mean the mismatch didn't
      // involve a parameter
      unsigned ParamNum =
          MismatchedParams.empty() ? 0 : MismatchedParams.front() + 1;
      NearMatches.push_back(std::make_pair(FD, ParamNum));
    }
  }
// If the qualified name lookup yielded nothing, try typo correction
} else if ((Correction = SemaRef.CorrectTypo(
                Prev.getLookupNameInfo(), Prev.getLookupKind(), S,
                &ExtraArgs.D.getCXXScopeSpec(), CCC, Sema::CTK_ErrorRecovery,
                IsLocalFriend ? nullptr : NewDC))) {
  // Set up everything for the call to ActOnFunctionDeclarator
  ExtraArgs.D.SetIdentifier(Correction.getCorrectionAsIdentifierInfo(),
                            ExtraArgs.D.getIdentifierLoc());
  Previous.clear();
  Previous.setLookupName(Correction.getCorrection());
  for (TypoCorrection::decl_iterator CDecl = Correction.begin(),
                                  CDeclEnd = Correction.end();
       CDecl != CDeclEnd; ++CDecl) {
    FunctionDecl *FD = dyn_cast<FunctionDecl>(*CDecl);
    if (FD && !FD->hasBody() &&
        hasSimilarParameters(SemaRef.Context, FD, NewFD, MismatchedParams)) {
      Previous.addDecl(FD);
    }
  }
  bool wasRedeclaration = ExtraArgs.D.isRedeclaration();

  NamedDecl *Result;
  // Retry building the function declaration with the new previous
  // declarations, and with errors suppressed.
  {
    // Trap errors.
    Sema::SFINAETrap Trap(SemaRef);

    // TODO: Refactor ActOnFunctionDeclarator so that we can call only the
    // pieces need to verify the typo-corrected C++ declaration and hopefully
    // eliminate the need for the parameter pack ExtraArgs.
    Result = SemaRef.ActOnFunctionDeclarator(
        ExtraArgs.S, ExtraArgs.D,
        Correction.getCorrectionDecl()->getDeclContext(),
        NewFD->getTypeSourceInfo(), Previous, ExtraArgs.TemplateParamLists,
        ExtraArgs.AddToScope);

    if (Trap.hasErrorOccurred())
      Result = nullptr;
  }

  if (Result) {
    // Determine which correction we picked.
    Decl *Canonical = Result->getCanonicalDecl();
    for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
         I != E; ++I)
      if ((*I)->getCanonicalDecl() == Canonical)
        Correction.setCorrectionDecl(*I);

    // Let Sema know about the correction.
    SemaRef.MarkTypoCorrectedFunctionDefinition(Result);
    SemaRef.diagnoseTypo(
        Correction,
        SemaRef.PDiag(IsLocalFriend
                        ? diag::err_no_matching_local_friend_suggest
                        : diag::err_member_decl_does_not_match_suggest)
          << Name << NewDC << IsDefinition);
    return Result;
  }

  // Pretend the typo correction never occurred
  ExtraArgs.D.SetIdentifier(Name.getAsIdentifierInfo(),
                            ExtraArgs.D.getIdentifierLoc());
  ExtraArgs.D.setRedeclaration(wasRedeclaration);
  Previous.clear();
  Previous.setLookupName(Name);
}

SemaRef.Diag(NewFD->getLocation(), DiagMsg)
    << Name << NewDC << IsDefinition << NewFD->getLocation();

bool NewFDisConst = false;
if (CXXMethodDecl *NewMD = dyn_cast<CXXMethodDecl>(NewFD))
  NewFDisConst = NewMD->isConst();

for (SmallVectorImpl<std::pair<FunctionDecl *, unsigned> >::iterator
     NearMatch = NearMatches.begin(), NearMatchEnd = NearMatches.end();
     NearMatch != NearMatchEnd; ++NearMatch) {
  FunctionDecl *FD = NearMatch->first;
  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
  bool FDisConst = MD && MD->isConst();
  bool IsMember = MD || !IsLocalFriend;

  // FIXME: These notes are poorly worded for the local friend case.
  if (unsigned Idx = NearMatch->second) {
    ParmVarDecl *FDParam = FD->getParamDecl(Idx-1);
    SourceLocation Loc = FDParam->getTypeSpecStartLoc();
    if (Loc.isInvalid()) Loc = FD->getLocation();
    SemaRef.Diag(Loc, IsMember ? diag::note_member_def_close_param_match
                               : diag::note_local_decl_close_param_match)
      << Idx << FDParam->getType()
      << NewFD->getParamDecl(Idx - 1)->getType();
  } else if (FDisConst != NewFDisConst) {
    SemaRef.Diag(FD->getLocation(), diag::note_member_def_close_const_match)
        << NewFDisConst << FD->getSourceRange().getEnd();
  } else
    SemaRef.Diag(FD->getLocation(),
                 IsMember ? diag::note_member_def_close_match
                          : diag::note_local_decl_close_match);
}
return nullptr;
8495}

8497static StorageClass getFunctionStorageClass(Sema &SemaRef, Declarator &D) {
switch (D.getDeclSpec().getStorageClassSpec()) {
default: llvm_unreachable("Unknown storage class!")__builtin_unreachable();
case DeclSpec::SCS_auto:
case DeclSpec::SCS_register:
case DeclSpec::SCS_mutable:
  SemaRef.Diag(D.getDeclSpec().getStorageClassSpecLoc(),
               diag::err_typecheck_sclass_func);
  D.getMutableDeclSpec().ClearStorageClassSpecs();
  D.setInvalidType();
  break;
case DeclSpec::SCS_unspecified: break;
case DeclSpec::SCS_extern:
  if (D.getDeclSpec().isExternInLinkageSpec())
    return SC_None;
  return SC_Extern;
case DeclSpec::SCS_static: {
  if (SemaRef.CurContext->getRedeclContext()->isFunctionOrMethod()) {
    // C99 6.7.1p5:
    //   The declaration of an identifier for a function that has
    //   block scope shall have no explicit storage-class specifier
    //   other than extern
    // See also (C++ [dcl.stc]p4).
    SemaRef.Diag(D.getDeclSpec().getStorageClassSpecLoc(),
                 diag::err_static_block_func);
    break;
  } else
    return SC_Static;
}
case DeclSpec::SCS_private_extern: return SC_PrivateExtern;
}

// No explicit storage class has already been returned
return SC_None;
8531}

8533static FunctionDecl *CreateNewFunctionDecl(Sema &SemaRef, Declarator &D,
                                         DeclContext *DC, QualType &R,
                                         TypeSourceInfo *TInfo,
                                         StorageClass SC,
                                         bool &IsVirtualOkay) {
DeclarationNameInfo NameInfo = SemaRef.GetNameForDeclarator(D);
DeclarationName Name = NameInfo.getName();

FunctionDecl *NewFD = nullptr;
bool isInline = D.getDeclSpec().isInlineSpecified();

if (!SemaRef.getLangOpts().CPlusPlus) {
  // Determine whether the function was written with a
  // prototype. This true when:
  //   - there is a prototype in the declarator, or
  //   - the type R of the function is some kind of typedef or other non-
  //     attributed reference to a type name (which eventually refers to a
  //     function type).
  bool HasPrototype =
    (D.isFunctionDeclarator() && D.getFunctionTypeInfo().hasPrototype) ||
    (!R->getAsAdjusted<FunctionType>() && R->isFunctionProtoType());

  NewFD = FunctionDecl::Create(SemaRef.Context, DC, D.getBeginLoc(), NameInfo,
                               R, TInfo, SC, isInline, HasPrototype,
                               ConstexprSpecKind::Unspecified,
                               /*TrailingRequiresClause=*/nullptr);
  if (D.isInvalidType())
    NewFD->setInvalidDecl();

  return NewFD;
}

ExplicitSpecifier ExplicitSpecifier = D.getDeclSpec().getExplicitSpecifier();

ConstexprSpecKind ConstexprKind = D.getDeclSpec().getConstexprSpecifier();
if (ConstexprKind == ConstexprSpecKind::Constinit) {
  SemaRef.Diag(D.getDeclSpec().getConstexprSpecLoc(),
               diag::err_constexpr_wrong_decl_kind)
      << static_cast<int>(ConstexprKind);
  ConstexprKind = ConstexprSpecKind::Unspecified;
  D.getMutableDeclSpec().ClearConstexprSpec();
}
Expr *TrailingRequiresClause = D.getTrailingRequiresClause();

// Check that the return type is not an abstract class type.
// For record types, this is done by the AbstractClassUsageDiagnoser once
// the class has been completely parsed.
if (!DC->isRecord() &&
    SemaRef.RequireNonAbstractType(
        D.getIdentifierLoc(), R->castAs<FunctionType>()->getReturnType(),
        diag::err_abstract_type_in_decl, SemaRef.AbstractReturnType))
  D.setInvalidType();

if (Name.getNameKind() == DeclarationName::CXXConstructorName) {
  // This is a C++ constructor declaration.
  assert(DC->isRecord() &&((void)0)
         "Constructors can only be declared in a member context")((void)0);

  R = SemaRef.CheckConstructorDeclarator(D, R, SC);
  return CXXConstructorDecl::Create(
      SemaRef.Context, cast<CXXRecordDecl>(DC), D.getBeginLoc(), NameInfo, R,
      TInfo, ExplicitSpecifier, isInline,
      /*isImplicitlyDeclared=*/false, ConstexprKind, InheritedConstructor(),
      TrailingRequiresClause);

} else if (Name.getNameKind() == DeclarationName::CXXDestructorName) {
  // This is a C++ destructor declaration.
  if (DC->isRecord()) {
    R = SemaRef.CheckDestructorDeclarator(D, R, SC);
    CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
    CXXDestructorDecl *NewDD = CXXDestructorDecl::Create(
        SemaRef.Context, Record, D.getBeginLoc(), NameInfo, R, TInfo,
        isInline, /*isImplicitlyDeclared=*/false, ConstexprKind,
        TrailingRequiresClause);

    // If the destructor needs an implicit exception specification, set it
    // now. FIXME: It'd be nice to be able to create the right type to start
    // with, but the type needs to reference the destructor declaration.
    if (SemaRef.getLangOpts().CPlusPlus11)
      SemaRef.AdjustDestructorExceptionSpec(NewDD);

    IsVirtualOkay = true;
    return NewDD;

  } else {
    SemaRef.Diag(D.getIdentifierLoc(), diag::err_destructor_not_member);
    D.setInvalidType();

    // Create a FunctionDecl to satisfy the function definition parsing
    // code path.
    return FunctionDecl::Create(SemaRef.Context, DC, D.getBeginLoc(),
                                D.getIdentifierLoc(), Name, R, TInfo, SC,
                                isInline,
                                /*hasPrototype=*/true, ConstexprKind,
                                TrailingRequiresClause);
  }

} else if (Name.getNameKind() == DeclarationName::CXXConversionFunctionName) {
  if (!DC->isRecord()) {
    SemaRef.Diag(D.getIdentifierLoc(),
         diag::err_conv_function_not_member);
    return nullptr;
  }

  SemaRef.CheckConversionDeclarator(D, R, SC);
  if (D.isInvalidType())
    return nullptr;

  IsVirtualOkay = true;
  return CXXConversionDecl::Create(
      SemaRef.Context, cast<CXXRecordDecl>(DC), D.getBeginLoc(), NameInfo, R,
      TInfo, isInline, ExplicitSpecifier, ConstexprKind, SourceLocation(),
      TrailingRequiresClause);

} else if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
  if (TrailingRequiresClause)
    SemaRef.Diag(TrailingRequiresClause->getBeginLoc(),
                 diag::err_trailing_requires_clause_on_deduction_guide)
        << TrailingRequiresClause->getSourceRange();
  SemaRef.CheckDeductionGuideDeclarator(D, R, SC);

  return CXXDeductionGuideDecl::Create(SemaRef.Context, DC, D.getBeginLoc(),
                                       ExplicitSpecifier, NameInfo, R, TInfo,
                                       D.getEndLoc());
} else if (DC->isRecord()) {
  // If the name of the function is the same as the name of the record,
  // then this must be an invalid constructor that has a return type.
  // (The parser checks for a return type and makes the declarator a
  // constructor if it has no return type).
  if (Name.getAsIdentifierInfo() &&
      Name.getAsIdentifierInfo() == cast<CXXRecordDecl>(DC)->getIdentifier()){
    SemaRef.Diag(D.getIdentifierLoc(), diag::err_constructor_return_type)
      << SourceRange(D.getDeclSpec().getTypeSpecTypeLoc())
      << SourceRange(D.getIdentifierLoc());
    return nullptr;
  }

  // This is a C++ method declaration.
  CXXMethodDecl *Ret = CXXMethodDecl::Create(
      SemaRef.Context, cast<CXXRecordDecl>(DC), D.getBeginLoc(), NameInfo, R,
      TInfo, SC, isInline, ConstexprKind, SourceLocation(),
      TrailingRequiresClause);
  IsVirtualOkay = !Ret->isStatic();
  return Ret;
} else {
  bool isFriend =
      SemaRef.getLangOpts().CPlusPlus && D.getDeclSpec().isFriendSpecified();
  if (!isFriend && SemaRef.CurContext->isRecord())
    return nullptr;

  // Determine whether the function was written with a
  // prototype. This true when:
  //   - we're in C++ (where every function has a prototype),
  return FunctionDecl::Create(SemaRef.Context, DC, D.getBeginLoc(), NameInfo,
                              R, TInfo, SC, isInline, true /*HasPrototype*/,
                              ConstexprKind, TrailingRequiresClause);
}
8690}

8692enum OpenCLParamType {
ValidKernelParam,
PtrPtrKernelParam,
PtrKernelParam,
InvalidAddrSpacePtrKernelParam,
InvalidKernelParam,
RecordKernelParam
8699};

8701static bool isOpenCLSizeDependentType(ASTContext &C, QualType Ty) {
// Size dependent types are just typedefs to normal integer types
// (e.g. unsigned long), so we cannot distinguish them from other typedefs to
// integers other than by their names.
StringRef SizeTypeNames[] = {"size_t", "intptr_t", "uintptr_t", "ptrdiff_t"};

// Remove typedefs one by one until we reach a typedef
// for a size dependent type.
QualType DesugaredTy = Ty;
do {
  ArrayRef<StringRef> Names(SizeTypeNames);
  auto Match = llvm::find(Names, DesugaredTy.getUnqualifiedType().getAsString());
  if (Names.end() != Match)
    return true;

  Ty = DesugaredTy;
  DesugaredTy = Ty.getSingleStepDesugaredType(C);
} while (DesugaredTy != Ty);

return false;
8721}

8723static OpenCLParamType getOpenCLKernelParameterType(Sema &S, QualType PT) {
if (PT->isDependentType())
  return InvalidKernelParam;

if (PT->isPointerType() || PT->isReferenceType()) {
  QualType PointeeType = PT->getPointeeType();
  if (PointeeType.getAddressSpace() == LangAS::opencl_generic ||
      PointeeType.getAddressSpace() == LangAS::opencl_private ||
      PointeeType.getAddressSpace() == LangAS::Default)
    return InvalidAddrSpacePtrKernelParam;

  if (PointeeType->isPointerType()) {
    // This is a pointer to pointer parameter.
    // Recursively check inner type.
    OpenCLParamType ParamKind = getOpenCLKernelParameterType(S, PointeeType);
    if (ParamKind == InvalidAddrSpacePtrKernelParam ||
        ParamKind == InvalidKernelParam)
      return ParamKind;

    return PtrPtrKernelParam;
  }

  // C++ for OpenCL v1.0 s2.4:
  // Moreover the types used in parameters of the kernel functions must be:
  // Standard layout types for pointer parameters. The same applies to
  // reference if an implementation supports them in kernel parameters.
  if (S.getLangOpts().OpenCLCPlusPlus &&
      !S.getOpenCLOptions().isAvailableOption(
          "__cl_clang_non_portable_kernel_param_types", S.getLangOpts()) &&
      !PointeeType->isAtomicType() && !PointeeType->isVoidType() &&
      !PointeeType->isStandardLayoutType())
    return InvalidKernelParam;

  return PtrKernelParam;
}

// OpenCL v1.2 s6.9.k:
// Arguments to kernel functions in a program cannot be declared with the
// built-in scalar types bool, half, size_t, ptrdiff_t, intptr_t, and
// uintptr_t or a struct and/or union that contain fields declared to be one
// of these built-in scalar types.
if (isOpenCLSizeDependentType(S.getASTContext(), PT))
  return InvalidKernelParam;

if (PT->isImageType())
  return PtrKernelParam;

if (PT->isBooleanType() || PT->isEventT() || PT->isReserveIDT())
  return InvalidKernelParam;

// OpenCL extension spec v1.2 s9.5:
// This extension adds support for half scalar and vector types as built-in
// types that can be used for arithmetic operations, conversions etc.
if (!S.getOpenCLOptions().isAvailableOption("cl_khr_fp16", S.getLangOpts()) &&
    PT->isHalfType())
  return InvalidKernelParam;

// Look into an array argument to check if it has a forbidden type.
if (PT->isArrayType()) {
  const Type *UnderlyingTy = PT->getPointeeOrArrayElementType();
  // Call ourself to check an underlying type of an array. Since the
  // getPointeeOrArrayElementType returns an innermost type which is not an
  // array, this recursive call only happens once.
  return getOpenCLKernelParameterType(S, QualType(UnderlyingTy, 0));
}

// C++ for OpenCL v1.0 s2.4:
// Moreover the types used in parameters of the kernel functions must be:
// Trivial and standard-layout types C++17 [basic.types] (plain old data
// types) for parameters passed by value;
if (S.getLangOpts().OpenCLCPlusPlus &&
    !S.getOpenCLOptions().isAvailableOption(
        "__cl_clang_non_portable_kernel_param_types", S.getLangOpts()) &&
    !PT->isOpenCLSpecificType() && !PT.isPODType(S.Context))
  return InvalidKernelParam;

if (PT->isRecordType())
  return RecordKernelParam;

return ValidKernelParam;
8803}

8805static void checkIsValidOpenCLKernelParameter(
Sema &S,
Declarator &D,
ParmVarDecl *Param,
llvm::SmallPtrSetImpl<const Type *> &ValidTypes) {
QualType PT = Param->getType();

// Cache the valid types we encounter to avoid rechecking structs that are
// used again
if (ValidTypes.count(PT.getTypePtr()))
  return;

switch (getOpenCLKernelParameterType(S, PT)) {
case PtrPtrKernelParam:
  // OpenCL v3.0 s6.11.a:
  // A kernel function argument cannot be declared as a pointer to a pointer
  // type. [...] This restriction only applies to OpenCL C 1.2 or below.
  if (S.getLangOpts().OpenCLVersion <= 120 &&
      !S.getLangOpts().OpenCLCPlusPlus) {
    S.Diag(Param->getLocation(), diag::err_opencl_ptrptr_kernel_param);
    D.setInvalidType();
    return;
  }

  ValidTypes.insert(PT.getTypePtr());
  return;

case InvalidAddrSpacePtrKernelParam:
  // OpenCL v1.0 s6.5:
  // __kernel function arguments declared to be a pointer of a type can point
  // to one of the following address spaces only : __global, __local or
  // __constant.
  S.Diag(Param->getLocation(), diag::err_kernel_arg_address_space);
  D.setInvalidType();
  return;

  // OpenCL v1.2 s6.9.k:
  // Arguments to kernel functions in a program cannot be declared with the
  // built-in scalar types bool, half, size_t, ptrdiff_t, intptr_t, and
  // uintptr_t or a struct and/or union that contain fields declared to be
  // one of these built-in scalar types.

case InvalidKernelParam:
  // OpenCL v1.2 s6.8 n:
  // A kernel function argument cannot be declared
  // of event_t type.
  // Do not diagnose half type since it is diagnosed as invalid argument
  // type for any function elsewhere.
  if (!PT->isHalfType()) {
    S.Diag(Param->getLocation(), diag::err_bad_kernel_param_type) << PT;

    // Explain what typedefs are involved.
    const TypedefType *Typedef = nullptr;
    while ((Typedef = PT->getAs<TypedefType>())) {
      SourceLocation Loc = Typedef->getDecl()->getLocation();
      // SourceLocation may be invalid for a built-in type.
      if (Loc.isValid())
        S.Diag(Loc, diag::note_entity_declared_at) << PT;
      PT = Typedef->desugar();
    }
  }

  D.setInvalidType();
  return;

case PtrKernelParam:
case ValidKernelParam:
  ValidTypes.insert(PT.getTypePtr());
  return;

case RecordKernelParam:
  break;
}

// Track nested structs we will inspect
SmallVector<const Decl *, 4> VisitStack;

// Track where we are in the nested structs. Items will migrate from
// VisitStack to HistoryStack as we do the DFS for bad field.
SmallVector<const FieldDecl *, 4> HistoryStack;
HistoryStack.push_back(nullptr);

// At this point we already handled everything except of a RecordType or
// an ArrayType of a RecordType.
assert((PT->isArrayType() || PT->isRecordType()) && "Unexpected type.")((void)0);
const RecordType *RecTy =
    PT->getPointeeOrArrayElementType()->getAs<RecordType>();
const RecordDecl *OrigRecDecl = RecTy->getDecl();

VisitStack.push_back(RecTy->getDecl());
assert(VisitStack.back() && "First decl null?")((void)0);

do {
  const Decl *Next = VisitStack.pop_back_val();
  if (!Next) {
    assert(!HistoryStack.empty())((void)0);
    // Found a marker, we have gone up a level
    if (const FieldDecl *Hist = HistoryStack.pop_back_val())
      ValidTypes.insert(Hist->getType().getTypePtr());

    continue;
  }

  // Adds everything except the original parameter declaration (which is not a
  // field itself) to the history stack.
  const RecordDecl *RD;
  if (const FieldDecl *Field = dyn_cast<FieldDecl>(Next)) {
    HistoryStack.push_back(Field);

    QualType FieldTy = Field->getType();
    // Other field types (known to be valid or invalid) are handled while we
    // walk around RecordDecl::fields().
    assert((FieldTy->isArrayType() || FieldTy->isRecordType()) &&((void)0)
           "Unexpected type.")((void)0);
    const Type *FieldRecTy = FieldTy->getPointeeOrArrayElementType();

    RD = FieldRecTy->castAs<RecordType>()->getDecl();
  } else {
    RD = cast<RecordDecl>(Next);
  }

  // Add a null marker so we know when we've gone back up a level
  VisitStack.push_back(nullptr);

  for (const auto *FD : RD->fields()) {
    QualType QT = FD->getType();

    if (ValidTypes.count(QT.getTypePtr()))
      continue;

    OpenCLParamType ParamType = getOpenCLKernelParameterType(S, QT);
    if (ParamType == ValidKernelParam)
      continue;

    if (ParamType == RecordKernelParam) {
      VisitStack.push_back(FD);
      continue;
    }

    // OpenCL v1.2 s6.9.p:
    // Arguments to kernel functions that are declared to be a struct or union
    // do not allow OpenCL objects to be passed as elements of the struct or
    // union.
    if (ParamType == PtrKernelParam || ParamType == PtrPtrKernelParam ||
        ParamType == InvalidAddrSpacePtrKernelParam) {
      S.Diag(Param->getLocation(),
             diag::err_record_with_pointers_kernel_param)
        << PT->isUnionType()
        << PT;
    } else {
      S.Diag(Param->getLocation(), diag::err_bad_kernel_param_type) << PT;
    }

    S.Diag(OrigRecDecl->getLocation(), diag::note_within_field_of_type)
        << OrigRecDecl->getDeclName();

    // We have an error, now let's go back up through history and show where
    // the offending field came from
    for (ArrayRef<const FieldDecl *>::const_iterator
             I = HistoryStack.begin() + 1,
             E = HistoryStack.end();
         I != E; ++I) {
      const FieldDecl *OuterField = *I;
      S.Diag(OuterField->getLocation(), diag::note_within_field_of_type)
        << OuterField->getType();
    }

    S.Diag(FD->getLocation(), diag::note_illegal_field_declared_here)
      << QT->isPointerType()
      << QT;
    D.setInvalidType();
    return;
  }
} while (!VisitStack.empty());
8979}

8981/// Find the DeclContext in which a tag is implicitly declared if we see an
8982/// elaborated type specifier in the specified context, and lookup finds
8983/// nothing.
8984static DeclContext *getTagInjectionContext(DeclContext *DC) {
while (!DC->isFileContext() && !DC->isFunctionOrMethod())
  DC = DC->getParent();
return DC;
8988}

8990/// Find the Scope in which a tag is implicitly declared if we see an
8991/// elaborated type specifier in the specified context, and lookup finds
8992/// nothing.
8993static Scope *getTagInjectionScope(Scope *S, const LangOptions &LangOpts) {
while (S->isClassScope() ||
       (LangOpts.CPlusPlus &&
        S->isFunctionPrototypeScope()) ||
       ((S->getFlags() & Scope::DeclScope) == 0) ||
       (S->getEntity() && S->getEntity()->isTransparentContext()))
  S = S->getParent();
return S;
9001}

9003NamedDecl*
9004Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
                            TypeSourceInfo *TInfo, LookupResult &Previous,
                            MultiTemplateParamsArg TemplateParamListsRef,
                            bool &AddToScope) {
QualType R = TInfo->getType();

assert(R->isFunctionType())((void)0);
if (R.getCanonicalType()->castAs<FunctionType>()->getCmseNSCallAttr())
  Diag(D.getIdentifierLoc(), diag::err_function_decl_cmse_ns_call);

SmallVector<TemplateParameterList *, 4> TemplateParamLists;
for (TemplateParameterList *TPL : TemplateParamListsRef)
  TemplateParamLists.push_back(TPL);
if (TemplateParameterList *Invented = D.getInventedTemplateParameterList()) {
  if (!TemplateParamLists.empty() &&
      Invented->getDepth() == TemplateParamLists.back()->getDepth())
    TemplateParamLists.back() = Invented;
  else
    TemplateParamLists.push_back(Invented);
}

// TODO: consider using NameInfo for diagnostic.
DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
DeclarationName Name = NameInfo.getName();
StorageClass SC = getFunctionStorageClass(*this, D);

if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
  Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
       diag::err_invalid_thread)
    << DeclSpec::getSpecifierName(TSCS);

if (D.isFirstDeclarationOfMember())
  adjustMemberFunctionCC(R, D.isStaticMember(), D.isCtorOrDtor(),
                         D.getIdentifierLoc());

bool isFriend = false;
FunctionTemplateDecl *FunctionTemplate = nullptr;
bool isMemberSpecialization = false;
bool isFunctionTemplateSpecialization = false;

bool isDependentClassScopeExplicitSpecialization = false;
bool HasExplicitTemplateArgs = false;
TemplateArgumentListInfo TemplateArgs;

bool isVirtualOkay = false;

DeclContext *OriginalDC = DC;
bool IsLocalExternDecl = adjustContextForLocalExternDecl(DC);

FunctionDecl *NewFD = CreateNewFunctionDecl(*this, D, DC, R, TInfo, SC,
                                            isVirtualOkay);
if (!NewFD) return nullptr;

if (OriginalLexicalContext && OriginalLexicalContext->isObjCContainer())
  NewFD->setTopLevelDeclInObjCContainer();

// Set the lexical context. If this is a function-scope declaration, or has a
// C++ scope specifier, or is the object of a friend declaration, the lexical
// context will be different from the semantic context.
NewFD->setLexicalDeclContext(CurContext);

if (IsLocalExternDecl)
  NewFD->setLocalExternDecl();

if (getLangOpts().CPlusPlus) {
  bool isInline = D.getDeclSpec().isInlineSpecified();
  bool isVirtual = D.getDeclSpec().isVirtualSpecified();
  bool hasExplicit = D.getDeclSpec().hasExplicitSpecifier();
  isFriend = D.getDeclSpec().isFriendSpecified();
  if (isFriend && !isInline && D.isFunctionDefinition()) {
    // C++ [class.friend]p5
    //   A function can be defined in a friend declaration of a
    //   class . . . . Such a function is implicitly inline.
    NewFD->setImplicitlyInline();
  }

  // If this is a method defined in an __interface, and is not a constructor
  // or an overloaded operator, then set the pure flag (isVirtual will already
  // return true).
  if (const CXXRecordDecl *Parent =
        dyn_cast<CXXRecordDecl>(NewFD->getDeclContext())) {
    if (Parent->isInterface() && cast<CXXMethodDecl>(NewFD)->isUserProvided())
      NewFD->setPure(true);

    // C++ [class.union]p2
    //   A union can have member functions, but not virtual functions.
    if (isVirtual && Parent->isUnion())
      Diag(D.getDeclSpec().getVirtualSpecLoc(), diag::err_virtual_in_union);
  }

  SetNestedNameSpecifier(*this, NewFD, D);
  isMemberSpecialization = false;
  isFunctionTemplateSpecialization = false;
  if (D.isInvalidType())
    NewFD->setInvalidDecl();

  // Match up the template parameter lists with the scope specifier, then
  // determine whether we have a template or a template specialization.
  bool Invalid = false;
  TemplateParameterList *TemplateParams =
      MatchTemplateParametersToScopeSpecifier(
          D.getDeclSpec().getBeginLoc(), D.getIdentifierLoc(),
          D.getCXXScopeSpec(),
          D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId
              ? D.getName().TemplateId
              : nullptr,
          TemplateParamLists, isFriend, isMemberSpecialization,
          Invalid);
  if (TemplateParams) {
    // Check that we can declare a template here.
    if (CheckTemplateDeclScope(S, TemplateParams))
      NewFD->setInvalidDecl();

    if (TemplateParams->size() > 0) {
      // This is a function template

      // A destructor cannot be a template.
      if (Name.getNameKind() == DeclarationName::CXXDestructorName) {
        Diag(NewFD->getLocation(), diag::err_destructor_template);
        NewFD->setInvalidDecl();
      }

      // If we're adding a template to a dependent context, we may need to
      // rebuilding some of the types used within the template parameter list,
      // now that we know what the current instantiation is.
      if (DC->isDependentContext()) {
        ContextRAII SavedContext(*this, DC);
        if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
          Invalid = true;
      }

      FunctionTemplate = FunctionTemplateDecl::Create(Context, DC,
                                                      NewFD->getLocation(),
                                                      Name, TemplateParams,
                                                      NewFD);
      FunctionTemplate->setLexicalDeclContext(CurContext);
      NewFD->setDescribedFunctionTemplate(FunctionTemplate);

      // For source fidelity, store the other template param lists.
      if (TemplateParamLists.size() > 1) {
        NewFD->setTemplateParameterListsInfo(Context,
            ArrayRef<TemplateParameterList *>(TemplateParamLists)
                .drop_back(1));
      }
    } else {
      // This is a function template specialization.
      isFunctionTemplateSpecialization = true;
      // For source fidelity, store all the template param lists.
      if (TemplateParamLists.size() > 0)
        NewFD->setTemplateParameterListsInfo(Context, TemplateParamLists);

      // C++0x [temp.expl.spec]p20 forbids "template<> friend void foo(int);".
      if (isFriend) {
        // We want to remove the "template<>", found here.
        SourceRange RemoveRange = TemplateParams->getSourceRange();

        // If we remove the template<> and the name is not a
        // template-id, we're actually silently creating a problem:
        // the friend declaration will refer to an untemplated decl,
        // and clearly the user wants a template specialization.  So
        // we need to insert '<>' after the name.
        SourceLocation InsertLoc;
        if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
          InsertLoc = D.getName().getSourceRange().getEnd();
          InsertLoc = getLocForEndOfToken(InsertLoc);
        }

        Diag(D.getIdentifierLoc(), diag::err_template_spec_decl_friend)
          << Name << RemoveRange
          << FixItHint::CreateRemoval(RemoveRange)
          << FixItHint::CreateInsertion(InsertLoc, "<>");
      }
    }
  } else {
    // Check that we can declare a template here.
    if (!TemplateParamLists.empty() && isMemberSpecialization &&
        CheckTemplateDeclScope(S, TemplateParamLists.back()))
      NewFD->setInvalidDecl();

    // All template param lists were matched against the scope specifier:
    // this is NOT (an explicit specialization of) a template.
    if (TemplateParamLists.size() > 0)
      // For source fidelity, store all the template param lists.
      NewFD->setTemplateParameterListsInfo(Context, TemplateParamLists);
  }

  if (Invalid) {
    NewFD->setInvalidDecl();
    if (FunctionTemplate)
      FunctionTemplate->setInvalidDecl();
  }

  // C++ [dcl.fct.spec]p5:
  //   The virtual specifier shall only be used in declarations of
  //   nonstatic class member functions that appear within a
  //   member-specification of a class declaration; see 10.3.
  //
  if (isVirtual && !NewFD->isInvalidDecl()) {
    if (!isVirtualOkay) {
      Diag(D.getDeclSpec().getVirtualSpecLoc(),
           diag::err_virtual_non_function);
    } else if (!CurContext->isRecord()) {
      // 'virtual' was specified outside of the class.
      Diag(D.getDeclSpec().getVirtualSpecLoc(),
           diag::err_virtual_out_of_class)
        << FixItHint::CreateRemoval(D.getDeclSpec().getVirtualSpecLoc());
    } else if (NewFD->getDescribedFunctionTemplate()) {
      // C++ [temp.mem]p3:
      //  A member function template shall not be virtual.
      Diag(D.getDeclSpec().getVirtualSpecLoc(),
           diag::err_virtual_member_function_template)
        << FixItHint::CreateRemoval(D.getDeclSpec().getVirtualSpecLoc());
    } else {
      // Okay: Add virtual to the method.
      NewFD->setVirtualAsWritten(true);
    }

    if (getLangOpts().CPlusPlus14 &&
        NewFD->getReturnType()->isUndeducedType())
      Diag(D.getDeclSpec().getVirtualSpecLoc(), diag::err_auto_fn_virtual);
  }

  if (getLangOpts().CPlusPlus14 &&
      (NewFD->isDependentContext() ||
       (isFriend && CurContext->isDependentContext())) &&
      NewFD->getReturnType()->isUndeducedType()) {
    // If the function template is referenced directly (for instance, as a
    // member of the current instantiation), pretend it has a dependent type.
    // This is not really justified by the standard, but is the only sane
    // thing to do.
    // FIXME: For a friend function, we have not marked the function as being
    // a friend yet, so 'isDependentContext' on the FD doesn't work.
    const FunctionProtoType *FPT =
        NewFD->getType()->castAs<FunctionProtoType>();
    QualType Result =
        SubstAutoType(FPT->getReturnType(), Context.DependentTy);
    NewFD->setType(Context.getFunctionType(Result, FPT->getParamTypes(),
                                           FPT->getExtProtoInfo()));
  }

  // C++ [dcl.fct.spec]p3:
  //  The inline specifier shall not appear on a block scope function
  //  declaration.
  if (isInline && !NewFD->isInvalidDecl()) {
    if (CurContext->isFunctionOrMethod()) {
      // 'inline' is not allowed on block scope function declaration.
      Diag(D.getDeclSpec().getInlineSpecLoc(),
           diag::err_inline_declaration_block_scope) << Name
        << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
    }
  }

  // C++ [dcl.fct.spec]p6:
  //  The explicit specifier shall be used only in the declaration of a
  //  constructor or conversion function within its class definition;
  //  see 12.3.1 and 12.3.2.
  if (hasExplicit && !NewFD->isInvalidDecl() &&
      !isa<CXXDeductionGuideDecl>(NewFD)) {
    if (!CurContext->isRecord()) {
      // 'explicit' was specified outside of the class.
      Diag(D.getDeclSpec().getExplicitSpecLoc(),
           diag::err_explicit_out_of_class)
          << FixItHint::CreateRemoval(D.getDeclSpec().getExplicitSpecRange());
    } else if (!isa<CXXConstructorDecl>(NewFD) &&
               !isa<CXXConversionDecl>(NewFD)) {
      // 'explicit' was specified on a function that wasn't a constructor
      // or conversion function.
      Diag(D.getDeclSpec().getExplicitSpecLoc(),
           diag::err_explicit_non_ctor_or_conv_function)
          << FixItHint::CreateRemoval(D.getDeclSpec().getExplicitSpecRange());
    }
  }

  ConstexprSpecKind ConstexprKind = D.getDeclSpec().getConstexprSpecifier();
  if (ConstexprKind != ConstexprSpecKind::Unspecified) {
    // C++11 [dcl.constexpr]p2: constexpr functions and constexpr constructors
    // are implicitly inline.
    NewFD->setImplicitlyInline();

    // C++11 [dcl.constexpr]p3: functions declared constexpr are required to
    // be either constructors or to return a literal type. Therefore,
    // destructors cannot be declared constexpr.
    if (isa<CXXDestructorDecl>(NewFD) &&
        (!getLangOpts().CPlusPlus20 ||
         ConstexprKind == ConstexprSpecKind::Consteval)) {
      Diag(D.getDeclSpec().getConstexprSpecLoc(), diag::err_constexpr_dtor)
          << static_cast<int>(ConstexprKind);
      NewFD->setConstexprKind(getLangOpts().CPlusPlus20
                                  ? ConstexprSpecKind::Unspecified
                                  : ConstexprSpecKind::Constexpr);
    }
    // C++20 [dcl.constexpr]p2: An allocation function, or a
    // deallocation function shall not be declared with the consteval
    // specifier.
    if (ConstexprKind == ConstexprSpecKind::Consteval &&
        (NewFD->getOverloadedOperator() == OO_New ||
         NewFD->getOverloadedOperator() == OO_Array_New ||
         NewFD->getOverloadedOperator() == OO_Delete ||
         NewFD->getOverloadedOperator() == OO_Array_Delete)) {
      Diag(D.getDeclSpec().getConstexprSpecLoc(),
           diag::err_invalid_consteval_decl_kind)
          << NewFD;
      NewFD->setConstexprKind(ConstexprSpecKind::Constexpr);
    }
  }

  // If __module_private__ was specified, mark the function accordingly.
  if (D.getDeclSpec().isModulePrivateSpecified()) {
    if (isFunctionTemplateSpecialization) {
      SourceLocation ModulePrivateLoc
        = D.getDeclSpec().getModulePrivateSpecLoc();
      Diag(ModulePrivateLoc, diag::err_module_private_specialization)
        << 0
        << FixItHint::CreateRemoval(ModulePrivateLoc);
    } else {
      NewFD->setModulePrivate();
      if (FunctionTemplate)
        FunctionTemplate->setModulePrivate();
    }
  }

  if (isFriend) {
    if (FunctionTemplate) {
      FunctionTemplate->setObjectOfFriendDecl();
      FunctionTemplate->setAccess(AS_public);
    }
    NewFD->setObjectOfFriendDecl();
    NewFD->setAccess(AS_public);
  }

  // If a function is defined as defaulted or deleted, mark it as such now.
  // We'll do the relevant checks on defaulted / deleted functions later.
  switch (D.getFunctionDefinitionKind()) {
  case FunctionDefinitionKind::Declaration:
  case FunctionDefinitionKind::Definition:
    break;

  case FunctionDefinitionKind::Defaulted:
    NewFD->setDefaulted();
    break;

  case FunctionDefinitionKind::Deleted:
    NewFD->setDeletedAsWritten();
    break;
  }

  if (isa<CXXMethodDecl>(NewFD) && DC == CurContext &&
      D.isFunctionDefinition()) {
    // C++ [class.mfct]p2:
    //   A member function may be defined (8.4) in its class definition, in
    //   which case it is an inline member function (7.1.2)
    NewFD->setImplicitlyInline();
  }

  if (SC == SC_Static && isa<CXXMethodDecl>(NewFD) &&
      !CurContext->isRecord()) {
    // C++ [class.static]p1:
    //   A data or function member of a class may be declared static
    //   in a class definition, in which case it is a static member of
    //   the class.

    // Complain about the 'static' specifier if it's on an out-of-line
    // member function definition.

    // MSVC permits the use of a 'static' storage specifier on an out-of-line
    // member function template declaration and class member template
    // declaration (MSVC versions before 2015), warn about this.
    Diag(D.getDeclSpec().getStorageClassSpecLoc(),
         ((!getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015) &&
           cast<CXXRecordDecl>(DC)->getDescribedClassTemplate()) ||
         (getLangOpts().MSVCCompat && NewFD->getDescribedFunctionTemplate()))
         ? diag::ext_static_out_of_line : diag::err_static_out_of_line)
      << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
  }

  // C++11 [except.spec]p15:
  //   A deallocation function with no exception-specification is treated
  //   as if it were specified with noexcept(true).
  const FunctionProtoType *FPT = R->getAs<FunctionProtoType>();
  if ((Name.getCXXOverloadedOperator() == OO_Delete ||
       Name.getCXXOverloadedOperator() == OO_Array_Delete) &&
      getLangOpts().CPlusPlus11 && FPT && !FPT->hasExceptionSpec())
    NewFD->setType(Context.getFunctionType(
        FPT->getReturnType(), FPT->getParamTypes(),
        FPT->getExtProtoInfo().withExceptionSpec(EST_BasicNoexcept)));
}

// Filter out previous declarations that don't match the scope.
FilterLookupForScope(Previous, OriginalDC, S, shouldConsiderLinkage(NewFD),
                     D.getCXXScopeSpec().isNotEmpty() ||
                     isMemberSpecialization ||
                     isFunctionTemplateSpecialization);

// Handle GNU asm-label extension (encoded as an attribute).
if (Expr *E = (Expr*) D.getAsmLabel()) {
  // The parser guarantees this is a string.
  StringLiteral *SE = cast<StringLiteral>(E);
  NewFD->addAttr(AsmLabelAttr::Create(Context, SE->getString(),
                                      /*IsLiteralLabel=*/true,
                                      SE->getStrTokenLoc(0)));
} else if (!ExtnameUndeclaredIdentifiers.empty()) {
  llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*>::iterator I =
    ExtnameUndeclaredIdentifiers.find(NewFD->getIdentifier());
  if (I != ExtnameUndeclaredIdentifiers.end()) {
    if (isDeclExternC(NewFD)) {
      NewFD->addAttr(I->second);
      ExtnameUndeclaredIdentifiers.erase(I);
    } else
      Diag(NewFD->getLocation(), diag::warn_redefine_extname_not_applied)
          << /*Variable*/0 << NewFD;
  }
}

// Copy the parameter declarations from the declarator D to the function
// declaration NewFD, if they are available.  First scavenge them into Params.
SmallVector<ParmVarDecl*, 16> Params;
unsigned FTIIdx;
if (D.isFunctionDeclarator(FTIIdx)) {
  DeclaratorChunk::FunctionTypeInfo &FTI = D.getTypeObject(FTIIdx).Fun;

  // Check for C99 6.7.5.3p10 - foo(void) is a non-varargs
  // function that takes no arguments, not a function that takes a
  // single void argument.
  // We let through "const void" here because Sema::GetTypeForDeclarator
  // already checks for that case.
  if (FTIHasNonVoidParameters(FTI) && FTI.Params[0].Param) {
    for (unsigned i = 0, e = FTI.NumParams; i != e; ++i) {
      ParmVarDecl *Param = cast<ParmVarDecl>(FTI.Params[i].Param);
      assert(Param->getDeclContext() != NewFD && "Was set before ?")((void)0);
      Param->setDeclContext(NewFD);
      Params.push_back(Param);

      if (Param->isInvalidDecl())
        NewFD->setInvalidDecl();
    }
  }

  if (!getLangOpts().CPlusPlus) {
    // In C, find all the tag declarations from the prototype and move them
    // into the function DeclContext. Remove them from the surrounding tag
    // injection context of the function, which is typically but not always
    // the TU.
    DeclContext *PrototypeTagContext =
        getTagInjectionContext(NewFD->getLexicalDeclContext());
    for (NamedDecl *NonParmDecl : FTI.getDeclsInPrototype()) {
      auto *TD = dyn_cast<TagDecl>(NonParmDecl);

      // We don't want to reparent enumerators. Look at their parent enum
      // instead.
      if (!TD) {
        if (auto *ECD = dyn_cast<EnumConstantDecl>(NonParmDecl))
          TD = cast<EnumDecl>(ECD->getDeclContext());
      }
      if (!TD)
        continue;
      DeclContext *TagDC = TD->getLexicalDeclContext();
      if (!TagDC->containsDecl(TD))
        continue;
      TagDC->removeDecl(TD);
      TD->setDeclContext(NewFD);
      NewFD->addDecl(TD);

      // Preserve the lexical DeclContext if it is not the surrounding tag
      // injection context of the FD. In this example, the semantic context of
      // E will be f and the lexical context will be S, while both the
      // semantic and lexical contexts of S will be f:
      //   void f(struct S { enum E { a } f; } s);
      if (TagDC != PrototypeTagContext)
        TD->setLexicalDeclContext(TagDC);
    }
  }
} else if (const FunctionProtoType *FT = R->getAs<FunctionProtoType>()) {
  // When we're declaring a function with a typedef, typeof, etc as in the
  // following example, we'll need to synthesize (unnamed)
  // parameters for use in the declaration.
  //
  // @code
  // typedef void fn(int);
  // fn f;
  // @endcode

  // Synthesize a parameter for each argument type.
  for (const auto &AI : FT->param_types()) {
    ParmVarDecl *Param =
        BuildParmVarDeclForTypedef(NewFD, D.getIdentifierLoc(), AI);
    Param->setScopeInfo(0, Params.size());
    Params.push_back(Param);
  }
} else {
  assert(R->isFunctionNoProtoType() && NewFD->getNumParams() == 0 &&((void)0)
         "Should not need args for typedef of non-prototype fn")((void)0);
}

// Finally, we know we have the right number of parameters, install them.
NewFD->setParams(Params);

if (D.getDeclSpec().isNoreturnSpecified())
  NewFD->addAttr(C11NoReturnAttr::Create(Context,
                                         D.getDeclSpec().getNoreturnSpecLoc(),
                                         AttributeCommonInfo::AS_Keyword));

// Functions returning a variably modified type violate C99 6.7.5.2p2
// because all functions have linkage.
if (!NewFD->isInvalidDecl() &&
    NewFD->getReturnType()->isVariablyModifiedType()) {
  Diag(NewFD->getLocation(), diag::err_vm_func_decl);
  NewFD->setInvalidDecl();
}

// Apply an implicit SectionAttr if '#pragma clang section text' is active
if (PragmaClangTextSection.Valid && D.isFunctionDefinition() &&
    !NewFD->hasAttr<SectionAttr>())
  NewFD->addAttr(PragmaClangTextSectionAttr::CreateImplicit(
      Context, PragmaClangTextSection.SectionName,
      PragmaClangTextSection.PragmaLocation, AttributeCommonInfo::AS_Pragma));

// Apply an implicit SectionAttr if #pragma code_seg is active.
if (CodeSegStack.CurrentValue && D.isFunctionDefinition() &&
    !NewFD->hasAttr<SectionAttr>()) {
  NewFD->addAttr(SectionAttr::CreateImplicit(
      Context, CodeSegStack.CurrentValue->getString(),
      CodeSegStack.CurrentPragmaLocation, AttributeCommonInfo::AS_Pragma,
      SectionAttr::Declspec_allocate));
  if (UnifySection(CodeSegStack.CurrentValue->getString(),
                   ASTContext::PSF_Implicit | ASTContext::PSF_Execute |
                       ASTContext::PSF_Read,
                   NewFD))
    NewFD->dropAttr<SectionAttr>();
}

// Apply an implicit CodeSegAttr from class declspec or
// apply an implicit SectionAttr from #pragma code_seg if active.
if (!NewFD->hasAttr<CodeSegAttr>()) {
  if (Attr *SAttr = getImplicitCodeSegOrSectionAttrForFunction(NewFD,
                                                               D.isFunctionDefinition())) {
    NewFD->addAttr(SAttr);
  }
}

// Handle attributes.
ProcessDeclAttributes(S, NewFD, D);

if (getLangOpts().OpenCL) {
  // OpenCL v1.1 s6.5: Using an address space qualifier in a function return
  // type declaration will generate a compilation error.
  LangAS AddressSpace = NewFD->getReturnType().getAddressSpace();
  if (AddressSpace != LangAS::Default) {
    Diag(NewFD->getLocation(),
         diag::err_opencl_return_value_with_address_space);
    NewFD->setInvalidDecl();
  }
}

if (LangOpts.SYCLIsDevice || (LangOpts.OpenMP && LangOpts.OpenMPIsDevice))
  checkDeviceDecl(NewFD, D.getBeginLoc());

if (!getLangOpts().CPlusPlus) {
  // Perform semantic checking on the function declaration.
  if (!NewFD->isInvalidDecl() && NewFD->isMain())
    CheckMain(NewFD, D.getDeclSpec());

  if (!NewFD->isInvalidDecl() && NewFD->isMSVCRTEntryPoint())
    CheckMSVCRTEntryPoint(NewFD);

  if (!NewFD->isInvalidDecl())
    D.setRedeclaration(CheckFunctionDeclaration(S, NewFD, Previous,
                                                isMemberSpecialization));
  else if (!Previous.empty())
    // Recover gracefully from an invalid redeclaration.
    D.setRedeclaration(true);
  assert((NewFD->isInvalidDecl() || !D.isRedeclaration() ||((void)0)
          Previous.getResultKind() != LookupResult::FoundOverloaded) &&((void)0)
         "previous declaration set still overloaded")((void)0);

  // Diagnose no-prototype function declarations with calling conventions that
  // don't support variadic calls. Only do this in C and do it after merging
  // possibly prototyped redeclarations.
  const FunctionType *FT = NewFD->getType()->castAs<FunctionType>();
  if (isa<FunctionNoProtoType>(FT) && !D.isFunctionDefinition()) {
    CallingConv CC = FT->getExtInfo().getCC();
    if (!supportsVariadicCall(CC)) {
      // Windows system headers sometimes accidentally use stdcall without
      // (void) parameters, so we relax this to a warning.
      int DiagID =
          CC == CC_X86StdCall ? diag::warn_cconv_knr : diag::err_cconv_knr;
      Diag(NewFD->getLocation(), DiagID)
          << FunctionType::getNameForCallConv(CC);
    }
  }

 if (NewFD->getReturnType().hasNonTrivialToPrimitiveDestructCUnion() ||
     NewFD->getReturnType().hasNonTrivialToPrimitiveCopyCUnion())
   checkNonTrivialCUnion(NewFD->getReturnType(),
                         NewFD->getReturnTypeSourceRange().getBegin(),
                         NTCUC_FunctionReturn, NTCUK_Destruct|NTCUK_Copy);
} else {
  // C++11 [replacement.functions]p3:
  //  The program's definitions shall not be specified as inline.
  //
  // N.B. We diagnose declarations instead of definitions per LWG issue 2340.
  //
  // Suppress the diagnostic if the function is __attribute__((used)), since
  // that forces an external definition to be emitted.
  if (D.getDeclSpec().isInlineSpecified() &&
      NewFD->isReplaceableGlobalAllocationFunction() &&
      !NewFD->hasAttr<UsedAttr>())
    Diag(D.getDeclSpec().getInlineSpecLoc(),
         diag::ext_operator_new_delete_declared_inline)
      << NewFD->getDeclName();

  // If the declarator is a template-id, translate the parser's template
  // argument list into our AST format.
  if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
    TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
    TemplateArgs.setLAngleLoc(TemplateId->LAngleLoc);
    TemplateArgs.setRAngleLoc(TemplateId->RAngleLoc);
    ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
                                       TemplateId->NumArgs);
    translateTemplateArguments(TemplateArgsPtr,
                               TemplateArgs);

    HasExplicitTemplateArgs = true;

    if (NewFD->isInvalidDecl()) {
      HasExplicitTemplateArgs = false;
    } else if (FunctionTemplate) {
      // Function template with explicit template arguments.
      Diag(D.getIdentifierLoc(), diag::err_function_template_partial_spec)
        << SourceRange(TemplateId->LAngleLoc, TemplateId->RAngleLoc);

      HasExplicitTemplateArgs = false;
    } else {
      assert((isFunctionTemplateSpecialization ||((void)0)
              D.getDeclSpec().isFriendSpecified()) &&((void)0)
             "should have a 'template<>' for this decl")((void)0);
      // "friend void foo<>(int);" is an implicit specialization decl.
      isFunctionTemplateSpecialization = true;
    }
  } else if (isFriend && isFunctionTemplateSpecialization) {
    // This combination is only possible in a recovery case;  the user
    // wrote something like:
    //   template <> friend void foo(int);
    // which we're recovering from as if the user had written:
    //   friend void foo<>(int);
    // Go ahead and fake up a template id.
    HasExplicitTemplateArgs = true;
    TemplateArgs.setLAngleLoc(D.getIdentifierLoc());
    TemplateArgs.setRAngleLoc(D.getIdentifierLoc());
  }

  // We do not add HD attributes to specializations here because
  // they may have different constexpr-ness compared to their
  // templates and, after maybeAddCUDAHostDeviceAttrs() is applied,
  // may end up with different effective targets. Instead, a
  // specialization inherits its target attributes from its template
  // in the CheckFunctionTemplateSpecialization() call below.
  if (getLangOpts().CUDA && !isFunctionTemplateSpecialization)
    maybeAddCUDAHostDeviceAttrs(NewFD, Previous);

  // If it's a friend (and only if it's a friend), it's possible
  // that either the specialized function type or the specialized
  // template is dependent, and therefore matching will fail.  In
  // this case, don't check the specialization yet.
  if (isFunctionTemplateSpecialization && isFriend &&
      (NewFD->getType()->isDependentType() || DC->isDependentContext() ||
       TemplateSpecializationType::anyInstantiationDependentTemplateArguments(
           TemplateArgs.arguments()))) {
    assert(HasExplicitTemplateArgs &&((void)0)
           "friend function specialization without template args")((void)0);
    if (CheckDependentFunctionTemplateSpecialization(NewFD, TemplateArgs,
                                                     Previous))
      NewFD->setInvalidDecl();
  } else if (isFunctionTemplateSpecialization) {
    if (CurContext->isDependentContext() && CurContext->isRecord()
        && !isFriend) {
      isDependentClassScopeExplicitSpecialization = true;
    } else if (!NewFD->isInvalidDecl() &&
               CheckFunctionTemplateSpecialization(
                   NewFD, (HasExplicitTemplateArgs ? &TemplateArgs : nullptr),
                   Previous))
      NewFD->setInvalidDecl();

    // C++ [dcl.stc]p1:
    //   A storage-class-specifier shall not be specified in an explicit
    //   specialization (14.7.3)
    FunctionTemplateSpecializationInfo *Info =
        NewFD->getTemplateSpecializationInfo();
    if (Info && SC != SC_None) {
      if (SC != Info->getTemplate()->getTemplatedDecl()->getStorageClass())
        Diag(NewFD->getLocation(),
             diag::err_explicit_specialization_inconsistent_storage_class)
          << SC
          << FixItHint::CreateRemoval(
                                    D.getDeclSpec().getStorageClassSpecLoc());

      else
        Diag(NewFD->getLocation(),
             diag::ext_explicit_specialization_storage_class)
          << FixItHint::CreateRemoval(
                                    D.getDeclSpec().getStorageClassSpecLoc());
    }
  } else if (isMemberSpecialization && isa<CXXMethodDecl>(NewFD)) {
    if (CheckMemberSpecialization(NewFD, Previous))
        NewFD->setInvalidDecl();
  }

  // Perform semantic checking on the function declaration.
  if (!isDependentClassScopeExplicitSpecialization) {
    if (!NewFD->isInvalidDecl() && NewFD->isMain())
      CheckMain(NewFD, D.getDeclSpec());

    if (!NewFD->isInvalidDecl() && NewFD->isMSVCRTEntryPoint())
      CheckMSVCRTEntryPoint(NewFD);

    if (!NewFD->isInvalidDecl())
      D.setRedeclaration(CheckFunctionDeclaration(S, NewFD, Previous,
                                                  isMemberSpecialization));
    else if (!Previous.empty())
      // Recover gracefully from an invalid redeclaration.
      D.setRedeclaration(true);
  }

  assert((NewFD->isInvalidDecl() || !D.isRedeclaration() ||((void)0)
          Previous.getResultKind() != LookupResult::FoundOverloaded) &&((void)0)
         "previous declaration set still overloaded")((void)0);

  NamedDecl *PrincipalDecl = (FunctionTemplate
                              ? cast<NamedDecl>(FunctionTemplate)
                              : NewFD);

  if (isFriend && NewFD->getPreviousDecl()) {
    AccessSpecifier Access = AS_public;
    if (!NewFD->isInvalidDecl())
      Access = NewFD->getPreviousDecl()->getAccess();

    NewFD->setAccess(Access);
    if (FunctionTemplate) FunctionTemplate->setAccess(Access);
  }

  if (NewFD->isOverloadedOperator() && !DC->isRecord() &&
      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
    PrincipalDecl->setNonMemberOperator();

  // If we have a function template, check the template parameter
  // list. This will check and merge default template arguments.
  if (FunctionTemplate) {
    FunctionTemplateDecl *PrevTemplate =
                                   FunctionTemplate->getPreviousDecl();
    CheckTemplateParameterList(FunctionTemplate->getTemplateParameters(),
                     PrevTemplate ? PrevTemplate->getTemplateParameters()
                                  : nullptr,
                          D.getDeclSpec().isFriendSpecified()
                            ? (D.isFunctionDefinition()
                                 ? TPC_FriendFunctionTemplateDefinition
                                 : TPC_FriendFunctionTemplate)
                            : (D.getCXXScopeSpec().isSet() &&
                               DC && DC->isRecord() &&
                               DC->isDependentContext())
                                ? TPC_ClassTemplateMember
                                : TPC_FunctionTemplate);
  }

  if (NewFD->isInvalidDecl()) {
    // Ignore all the rest of this.
  } else if (!D.isRedeclaration()) {
    struct ActOnFDArgs ExtraArgs = { S, D, TemplateParamLists,
                                     AddToScope };
    // Fake up an access specifier if it's supposed to be a class member.
    if (isa<CXXRecordDecl>(NewFD->getDeclContext()))
      NewFD->setAccess(AS_public);

    // Qualified decls generally require a previous declaration.
    if (D.getCXXScopeSpec().isSet()) {
      // ...with the major exception of templated-scope or
      // dependent-scope friend declarations.

      // TODO: we currently also suppress this check in dependent
      // contexts because (1) the parameter depth will be off when
      // matching friend templates and (2) we might actually be
      // selecting a friend based on a dependent factor.  But there
      // are situations where these conditions don't apply and we
      // can actually do this check immediately.
      //
      // Unless the scope is dependent, it's always an error if qualified
      // redeclaration lookup found nothing at all. Diagnose that now;
      // nothing will diagnose that error later.
      if (isFriend &&
          (D.getCXXScopeSpec().getScopeRep()->isDependent() ||
           (!Previous.empty() && CurContext->isDependentContext()))) {
        // ignore these
      } else if (NewFD->isCPUDispatchMultiVersion() ||
                 NewFD->isCPUSpecificMultiVersion()) {
        // ignore this, we allow the redeclaration behavior here to create new
        // versions of the function.
      } else {
        // The user tried to provide an out-of-line definition for a
        // function that is a member of a class or namespace, but there
        // was no such member function declared (C++ [class.mfct]p2,
        // C++ [namespace.memdef]p2). For example:
        //
        // class X {
        //   void f() const;
        // };
        //
        // void X::f() { } // ill-formed
        //
        // Complain about this problem, and attempt to suggest close
        // matches (e.g., those that differ only in cv-qualifiers and
        // whether the parameter types are references).

        if (NamedDecl *Result = DiagnoseInvalidRedeclaration(
                *this, Previous, NewFD, ExtraArgs, false, nullptr)) {
          AddToScope = ExtraArgs.AddToScope;
          return Result;
        }
      }

      // Unqualified local friend declarations are required to resolve
      // to something.
    } else if (isFriend && cast<CXXRecordDecl>(CurContext)->isLocalClass()) {
      if (NamedDecl *Result = DiagnoseInvalidRedeclaration(
              *this, Previous, NewFD, ExtraArgs, true, S)) {
        AddToScope = ExtraArgs.AddToScope;
        return Result;
      }
    }
  } else if (!D.isFunctionDefinition() &&
             isa<CXXMethodDecl>(NewFD) && NewFD->isOutOfLine() &&
             !isFriend && !isFunctionTemplateSpecialization &&
             !isMemberSpecialization) {
    // An out-of-line member function declaration must also be a
    // definition (C++ [class.mfct]p2).
    // Note that this is not the case for explicit specializations of
    // function templates or member functions of class templates, per
    // C++ [temp.expl.spec]p2. We also allow these declarations as an
    // extension for compatibility with old SWIG code which likes to
    // generate them.
    Diag(NewFD->getLocation(), diag::ext_out_of_line_declaration)
      << D.getCXXScopeSpec().getRange();
  }
}

// If this is the first declaration of a library builtin function, add
// attributes as appropriate.
if (!D.isRedeclaration() &&
    NewFD->getDeclContext()->getRedeclContext()->isFileContext()) {
  if (IdentifierInfo *II = Previous.getLookupName().getAsIdentifierInfo()) {
    if (unsigned BuiltinID = II->getBuiltinID()) {
      if (NewFD->getLanguageLinkage() == CLanguageLinkage) {
        // Validate the type matches unless this builtin is specified as
        // matching regardless of its declared type.
        if (Context.BuiltinInfo.allowTypeMismatch(BuiltinID)) {
          NewFD->addAttr(BuiltinAttr::CreateImplicit(Context, BuiltinID));
        } else {
          ASTContext::GetBuiltinTypeError Error;
          LookupNecessaryTypesForBuiltin(S, BuiltinID);
          QualType BuiltinType = Context.GetBuiltinType(BuiltinID, Error);

          if (!Error && !BuiltinType.isNull() &&
              Context.hasSameFunctionTypeIgnoringExceptionSpec(
                  NewFD->getType(), BuiltinType))
            NewFD->addAttr(BuiltinAttr::CreateImplicit(Context, BuiltinID));
        }
      } else if (BuiltinID == Builtin::BI__GetExceptionInfo &&
                 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
        // FIXME: We should consider this a builtin only in the std namespace.
        NewFD->addAttr(BuiltinAttr::CreateImplicit(Context, BuiltinID));
      }
    }
  }
}

ProcessPragmaWeak(S, NewFD);
checkAttributesAfterMerging(*this, *NewFD);

AddKnownFunctionAttributes(NewFD);

if (NewFD->hasAttr<OverloadableAttr>() &&
    !NewFD->getType()->getAs<FunctionProtoType>()) {
  Diag(NewFD->getLocation(),
       diag::err_attribute_overloadable_no_prototype)
    << NewFD;

  // Turn this into a variadic function with no parameters.
  const FunctionType *FT = NewFD->getType()->getAs<FunctionType>();
  FunctionProtoType::ExtProtoInfo EPI(
      Context.getDefaultCallingConvention(true, false));
  EPI.Variadic = true;
  EPI.ExtInfo = FT->getExtInfo();

  QualType R = Context.getFunctionType(FT->getReturnType(), None, EPI);
  NewFD->setType(R);
}

// If there's a #pragma GCC visibility in scope, and this isn't a class
// member, set the visibility of this function.
if (!DC->isRecord() && NewFD->isExternallyVisible())
  AddPushedVisibilityAttribute(NewFD);

// If there's a #pragma clang arc_cf_code_audited in scope, consider
// marking the function.
AddCFAuditedAttribute(NewFD);

// If this is a function definition, check if we have to apply optnone due to
// a pragma.
if(D.isFunctionDefinition())
  AddRangeBasedOptnone(NewFD);

// If this is the first declaration of an extern C variable, update
// the map of such variables.
if (NewFD->isFirstDecl() && !NewFD->isInvalidDecl() &&
    isIncompleteDeclExternC(*this, NewFD))
  RegisterLocallyScopedExternCDecl(NewFD, S);

// Set this FunctionDecl's range up to the right paren.
NewFD->setRangeEnd(D.getSourceRange().getEnd());

if (D.isRedeclaration() && !Previous.empty()) {
  NamedDecl *Prev = Previous.getRepresentativeDecl();
  checkDLLAttributeRedeclaration(*this, Prev, NewFD,
                                 isMemberSpecialization ||
                                     isFunctionTemplateSpecialization,
                                 D.isFunctionDefinition());
}

if (getLangOpts().CUDA) {
  IdentifierInfo *II = NewFD->getIdentifier();
  if (II && II->isStr(getCudaConfigureFuncName()) &&
      !NewFD->isInvalidDecl() &&
      NewFD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
    if (!R->castAs<FunctionType>()->getReturnType()->isScalarType())
      Diag(NewFD->getLocation(), diag::err_config_scalar_return)
          << getCudaConfigureFuncName();
    Context.setcudaConfigureCallDecl(NewFD);
  }

  // Variadic functions, other than a *declaration* of printf, are not allowed
  // in device-side CUDA code, unless someone passed
  // -fcuda-allow-variadic-functions.
  if (!getLangOpts().CUDAAllowVariadicFunctions && NewFD->isVariadic() &&
      (NewFD->hasAttr<CUDADeviceAttr>() ||
       NewFD->hasAttr<CUDAGlobalAttr>()) &&
      !(II && II->isStr("printf") && NewFD->isExternC() &&
        !D.isFunctionDefinition())) {
    Diag(NewFD->getLocation(), diag::err_variadic_device_fn);
  }
}

MarkUnusedFileScopedDecl(NewFD);



if (getLangOpts().OpenCL && NewFD->hasAttr<OpenCLKernelAttr>()) {
  // OpenCL v1.2 s6.8 static is invalid for kernel functions.
  if ((getLangOpts().OpenCLVersion >= 120)
      && (SC == SC_Static)) {
    Diag(D.getIdentifierLoc(), diag::err_static_kernel);
    D.setInvalidType();
  }

  // OpenCL v1.2, s6.9 -- Kernels can only have return type void.
  if (!NewFD->getReturnType()->isVoidType()) {
    SourceRange RTRange = NewFD->getReturnTypeSourceRange();
    Diag(D.getIdentifierLoc(), diag::err_expected_kernel_void_return_type)
        << (RTRange.isValid() ? FixItHint::CreateReplacement(RTRange, "void")
                              : FixItHint());
    D.setInvalidType();
  }

  llvm::SmallPtrSet<const Type *, 16> ValidTypes;
  for (auto Param : NewFD->parameters())
    checkIsValidOpenCLKernelParameter(*this, D, Param, ValidTypes);

  if (getLangOpts().OpenCLCPlusPlus) {
    if (DC->isRecord()) {
      Diag(D.getIdentifierLoc(), diag::err_method_kernel);
      D.setInvalidType();
    }
    if (FunctionTemplate) {
      Diag(D.getIdentifierLoc(), diag::err_template_kernel);
      D.setInvalidType();
    }
  }
}

if (getLangOpts().CPlusPlus) {
  if (FunctionTemplate) {
    if (NewFD->isInvalidDecl())
      FunctionTemplate->setInvalidDecl();
    return FunctionTemplate;
  }

  if (isMemberSpecialization && !NewFD->isInvalidDecl())
    CompleteMemberSpecialization(NewFD, Previous);
}

for (const ParmVarDecl *Param : NewFD->parameters()) {
  QualType PT = Param->getType();

  // OpenCL 2.0 pipe restrictions forbids pipe packet types to be non-value
  // types.
  if (getLangOpts().OpenCLVersion >= 200 || getLangOpts().OpenCLCPlusPlus) {
    if(const PipeType *PipeTy = PT->getAs<PipeType>()) {
      QualType ElemTy = PipeTy->getElementType();
        if (ElemTy->isReferenceType() || ElemTy->isPointerType()) {
          Diag(Param->getTypeSpecStartLoc(), diag::err_reference_pipe_type );
          D.setInvalidType();
        }
    }
  }
}

// Here we have an function template explicit specialization at class scope.
// The actual specialization will be postponed to template instatiation
// time via the ClassScopeFunctionSpecializationDecl node.
if (isDependentClassScopeExplicitSpecialization) {
  ClassScopeFunctionSpecializationDecl *NewSpec =
                       ClassScopeFunctionSpecializationDecl::Create(
                              Context, CurContext, NewFD->getLocation(),
                              cast<CXXMethodDecl>(NewFD),
                              HasExplicitTemplateArgs, TemplateArgs);
  CurContext->addDecl(NewSpec);
  AddToScope = false;
}

// Diagnose availability attributes. Availability cannot be used on functions
// that are run during load/unload.
if (const auto *attr = NewFD->getAttr<AvailabilityAttr>()) {
  if (NewFD->hasAttr<ConstructorAttr>()) {
    Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
        << 1;
    NewFD->dropAttr<AvailabilityAttr>();
  }
  if (NewFD->hasAttr<DestructorAttr>()) {
    Diag(attr->getLocation(), diag::warn_availability_on_static_initializer)
        << 2;
    NewFD->dropAttr<AvailabilityAttr>();
  }
}

// Diagnose no_builtin attribute on function declaration that are not a
// definition.
// FIXME: We should really be doing this in
// SemaDeclAttr.cpp::handleNoBuiltinAttr, unfortunately we only have access to
// the FunctionDecl and at this point of the code
// FunctionDecl::isThisDeclarationADefinition() which always returns `false`
// because Sema::ActOnStartOfFunctionDef has not been called yet.
if (const auto *NBA = NewFD->getAttr<NoBuiltinAttr>())
  switch (D.getFunctionDefinitionKind()) {
  case FunctionDefinitionKind::Defaulted:
  case FunctionDefinitionKind::Deleted:
    Diag(NBA->getLocation(),
         diag::err_attribute_no_builtin_on_defaulted_deleted_function)
        << NBA->getSpelling();
    break;
  case FunctionDefinitionKind::Declaration:
    Diag(NBA->getLocation(), diag::err_attribute_no_builtin_on_non_definition)
        << NBA->getSpelling();
    break;
  case FunctionDefinitionKind::Definition:
    break;
  }

return NewFD;
10068}

10070/// Return a CodeSegAttr from a containing class.  The Microsoft docs say
10071/// when __declspec(code_seg) "is applied to a class, all member functions of
10072/// the class and nested classes -- this includes compiler-generated special
10073/// member functions -- are put in the specified segment."
10074/// The actual behavior is a little more complicated. The Microsoft compiler
10075/// won't check outer classes if there is an active value from #pragma code_seg.
10076/// The CodeSeg is always applied from the direct parent but only from outer
10077/// classes when the #pragma code_seg stack is empty. See:
10078/// https://reviews.llvm.org/D22931, the Microsoft feedback page is no longer
10079/// available since MS has removed the page.
10080static Attr *getImplicitCodeSegAttrFromClass(Sema &S, const FunctionDecl *FD) {
const auto *Method = dyn_cast<CXXMethodDecl>(FD);
if (!Method)
  return nullptr;
const CXXRecordDecl *Parent = Method->getParent();
if (const auto *SAttr = Parent->getAttr<CodeSegAttr>()) {
  Attr *NewAttr = SAttr->clone(S.getASTContext());
  NewAttr->setImplicit(true);
  return NewAttr;
}

// The Microsoft compiler won't check outer classes for the CodeSeg
// when the #pragma code_seg stack is active.
if (S.CodeSegStack.CurrentValue)
 return nullptr;

while ((Parent = dyn_cast<CXXRecordDecl>(Parent->getParent()))) {
  if (const auto *SAttr = Parent->getAttr<CodeSegAttr>()) {
    Attr *NewAttr = SAttr->clone(S.getASTContext());
    NewAttr->setImplicit(true);
    return NewAttr;
  }
}
return nullptr;
10104}

10106/// Returns an implicit CodeSegAttr if a __declspec(code_seg) is found on a
10107/// containing class. Otherwise it will return implicit SectionAttr if the
10108/// function is a definition and there is an active value on CodeSegStack
10109/// (from the current #pragma code-seg value).
10110///
10111/// \param FD Function being declared.
10112/// \param IsDefinition Whether it is a definition or just a declarartion.
10113/// \returns A CodeSegAttr or SectionAttr to apply to the function or
10114///          nullptr if no attribute should be added.
10115Attr *Sema::getImplicitCodeSegOrSectionAttrForFunction(const FunctionDecl *FD,
                                                     bool IsDefinition) {
if (Attr *A = getImplicitCodeSegAttrFromClass(*this, FD))
  return A;
if (!FD->hasAttr<SectionAttr>() && IsDefinition &&
    CodeSegStack.CurrentValue)
  return SectionAttr::CreateImplicit(
      getASTContext(), CodeSegStack.CurrentValue->getString(),
      CodeSegStack.CurrentPragmaLocation, AttributeCommonInfo::AS_Pragma,
      SectionAttr::Declspec_allocate);
return nullptr;
10126}

10128/// Determines if we can perform a correct type check for \p D as a
10129/// redeclaration of \p PrevDecl. If not, we can generally still perform a
10130/// best-effort check.
10131///
10132/// \param NewD The new declaration.
10133/// \param OldD The old declaration.
10134/// \param NewT The portion of the type of the new declaration to check.
10135/// \param OldT The portion of the type of the old declaration to check.
10136bool Sema::canFullyTypeCheckRedeclaration(ValueDecl *NewD, ValueDecl *OldD,
                                        QualType NewT, QualType OldT) {
if (!NewD->getLexicalDeclContext()->isDependentContext())
  return true;

// For dependently-typed local extern declarations and friends, we can't
// perform a correct type check in general until instantiation:
//
//   int f();
//   template<typename T> void g() { T f(); }
//
// (valid if g() is only instantiated with T = int).
if (NewT->isDependentType() &&
    (NewD->isLocalExternDecl() || NewD->getFriendObjectKind()))
  return false;

// Similarly, if the previous declaration was a dependent local extern
// declaration, we don't really know its type yet.
if (OldT->isDependentType() && OldD->isLocalExternDecl())
  return false;

return true;
10158}

10160/// Checks if the new declaration declared in dependent context must be
10161/// put in the same redeclaration chain as the specified declaration.
10162///
10163/// \param D Declaration that is checked.
10164/// \param PrevDecl Previous declaration found with proper lookup method for the
10165///                 same declaration name.
10166/// \returns True if D must be added to the redeclaration chain which PrevDecl
10167///          belongs to.
10168///
10169bool Sema::shouldLinkDependentDeclWithPrevious(Decl *D, Decl *PrevDecl) {
if (!D->getLexicalDeclContext()->isDependentContext())
  return true;

// Don't chain dependent friend function definitions until instantiation, to
// permit cases like
//
//   void func();
//   template<typename T> class C1 { friend void func() {} };
//   template<typename T> class C2 { friend void func() {} };
//
// ... which is valid if only one of C1 and C2 is ever instantiated.
//
// FIXME: This need only apply to function definitions. For now, we proxy
// this by checking for a file-scope function. We do not want this to apply
// to friend declarations nominating member functions, because that gets in
// the way of access checks.
if (D->getFriendObjectKind() && D->getDeclContext()->isFileContext())
  return false;

auto *VD = dyn_cast<ValueDecl>(D);
auto *PrevVD = dyn_cast<ValueDecl>(PrevDecl);
return !VD || !PrevVD ||
       canFullyTypeCheckRedeclaration(VD, PrevVD, VD->getType(),
                                      PrevVD->getType());
10194}

10196/// Check the target attribute of the function for MultiVersion
10197/// validity.
10198///
10199/// Returns true if there was an error, false otherwise.
10200static bool CheckMultiVersionValue(Sema &S, const FunctionDecl *FD) {
const auto *TA = FD->getAttr<TargetAttr>();
assert(TA && "MultiVersion Candidate requires a target attribute")((void)0);
ParsedTargetAttr ParseInfo = TA->parse();
const TargetInfo &TargetInfo = S.Context.getTargetInfo();
enum ErrType { Feature = 0, Architecture = 1 };

if (!ParseInfo.Architecture.empty() &&
    !TargetInfo.validateCpuIs(ParseInfo.Architecture)) {
  S.Diag(FD->getLocation(), diag::err_bad_multiversion_option)
      << Architecture << ParseInfo.Architecture;
  return true;
}

for (const auto &Feat : ParseInfo.Features) {
  auto BareFeat = StringRef{Feat}.substr(1);
  if (Feat[0] == '-') {
    S.Diag(FD->getLocation(), diag::err_bad_multiversion_option)
        << Feature << ("no-" + BareFeat).str();
    return true;
  }

  if (!TargetInfo.validateCpuSupports(BareFeat) ||
      !TargetInfo.isValidFeatureName(BareFeat)) {
    S.Diag(FD->getLocation(), diag::err_bad_multiversion_option)
        << Feature << BareFeat;
    return true;
  }
}
return false;
10230}

10232// Provide a white-list of attributes that are allowed to be combined with
10233// multiversion functions.
10234static bool AttrCompatibleWithMultiVersion(attr::Kind Kind,
                                         MultiVersionKind MVType) {
// Note: this list/diagnosis must match the list in
// checkMultiversionAttributesAllSame.
switch (Kind) {
default:
  return false;
case attr::Used:
  return MVType == MultiVersionKind::Target;
case attr::NonNull:
case attr::NoThrow:
  return true;
}
10247}

10249static bool checkNonMultiVersionCompatAttributes(Sema &S,
                                               const FunctionDecl *FD,
                                               const FunctionDecl *CausedFD,
                                               MultiVersionKind MVType) {
bool IsCPUSpecificCPUDispatchMVType =
    MVType == MultiVersionKind::CPUDispatch ||
    MVType == MultiVersionKind::CPUSpecific;
const auto Diagnose = [FD, CausedFD, IsCPUSpecificCPUDispatchMVType](
                          Sema &S, const Attr *A) {
  S.Diag(FD->getLocation(), diag::err_multiversion_disallowed_other_attr)
      << IsCPUSpecificCPUDispatchMVType << A;
  if (CausedFD)
    S.Diag(CausedFD->getLocation(), diag::note_multiversioning_caused_here);
  return true;
};

for (const Attr *A : FD->attrs()) {
  switch (A->getKind()) {
  case attr::CPUDispatch:
  case attr::CPUSpecific:
    if (MVType != MultiVersionKind::CPUDispatch &&
        MVType != MultiVersionKind::CPUSpecific)
      return Diagnose(S, A);
    break;
  case attr::Target:
    if (MVType != MultiVersionKind::Target)
      return Diagnose(S, A);
    break;
  default:
    if (!AttrCompatibleWithMultiVersion(A->getKind(), MVType))
      return Diagnose(S, A);
    break;
  }
}
return false;
10284}

10286bool Sema::areMultiversionVariantFunctionsCompatible(
  const FunctionDecl *OldFD, const FunctionDecl *NewFD,
  const PartialDiagnostic &NoProtoDiagID,
  const PartialDiagnosticAt &NoteCausedDiagIDAt,
  const PartialDiagnosticAt &NoSupportDiagIDAt,
  const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
  bool ConstexprSupported, bool CLinkageMayDiffer) {
enum DoesntSupport {
  FuncTemplates = 0,
  VirtFuncs = 1,
  DeducedReturn = 2,
  Constructors = 3,
  Destructors = 4,
  DeletedFuncs = 5,
  DefaultedFuncs = 6,
  ConstexprFuncs = 7,
  ConstevalFuncs = 8,
};
enum Different {
  CallingConv = 0,
  ReturnType = 1,
  ConstexprSpec = 2,
  InlineSpec = 3,
  StorageClass = 4,
  Linkage = 5,
};

if (NoProtoDiagID.getDiagID() != 0 && OldFD &&
    !OldFD->getType()->getAs<FunctionProtoType>()) {
  Diag(OldFD->getLocation(), NoProtoDiagID);
  Diag(NoteCausedDiagIDAt.first, NoteCausedDiagIDAt.second);
  return true;
}

if (NoProtoDiagID.getDiagID() != 0 &&
    !NewFD->getType()->getAs<FunctionProtoType>())
  return Diag(NewFD->getLocation(), NoProtoDiagID);

if (!TemplatesSupported &&
    NewFD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)
  return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
         << FuncTemplates;

if (const auto *NewCXXFD = dyn_cast<CXXMethodDecl>(NewFD)) {
  if (NewCXXFD->isVirtual())
    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
           << VirtFuncs;

  if (isa<CXXConstructorDecl>(NewCXXFD))
    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
           << Constructors;

  if (isa<CXXDestructorDecl>(NewCXXFD))
    return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
           << Destructors;
}

if (NewFD->isDeleted())
  return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
         << DeletedFuncs;

if (NewFD->isDefaulted())
  return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
         << DefaultedFuncs;

if (!ConstexprSupported && NewFD->isConstexpr())
  return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
         << (NewFD->isConsteval() ? ConstevalFuncs : ConstexprFuncs);

QualType NewQType = Context.getCanonicalType(NewFD->getType());
const auto *NewType = cast<FunctionType>(NewQType);
QualType NewReturnType = NewType->getReturnType();

if (NewReturnType->isUndeducedType())
  return Diag(NoSupportDiagIDAt.first, NoSupportDiagIDAt.second)
         << DeducedReturn;

// Ensure the return type is identical.
if (OldFD) {
  QualType OldQType = Context.getCanonicalType(OldFD->getType());
  const auto *OldType = cast<FunctionType>(OldQType);
  FunctionType::ExtInfo OldTypeInfo = OldType->getExtInfo();
  FunctionType::ExtInfo NewTypeInfo = NewType->getExtInfo();

  if (OldTypeInfo.getCC() != NewTypeInfo.getCC())
    return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << CallingConv;

  QualType OldReturnType = OldType->getReturnType();

  if (OldReturnType != NewReturnType)
    return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << ReturnType;

  if (OldFD->getConstexprKind() != NewFD->getConstexprKind())
    return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << ConstexprSpec;

  if (OldFD->isInlineSpecified() != NewFD->isInlineSpecified())
    return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << InlineSpec;

  if (OldFD->getStorageClass() != NewFD->getStorageClass())
    return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << StorageClass;

  if (!CLinkageMayDiffer && OldFD->isExternC() != NewFD->isExternC())
    return Diag(DiffDiagIDAt.first, DiffDiagIDAt.second) << Linkage;

  if (CheckEquivalentExceptionSpec(
          OldFD->getType()->getAs<FunctionProtoType>(), OldFD->getLocation(),
          NewFD->getType()->getAs<FunctionProtoType>(), NewFD->getLocation()))
    return true;
}
return false;
10396}

10398static bool CheckMultiVersionAdditionalRules(Sema &S, const FunctionDecl *OldFD,
                                           const FunctionDecl *NewFD,
                                           bool CausesMV,
                                           MultiVersionKind MVType) {
if (!S.getASTContext().getTargetInfo().supportsMultiVersioning()) {
  S.Diag(NewFD->getLocation(), diag::err_multiversion_not_supported);
  if (OldFD)
    S.Diag(OldFD->getLocation(), diag::note_previous_declaration);
  return true;
}

bool IsCPUSpecificCPUDispatchMVType =
    MVType == MultiVersionKind::CPUDispatch ||
    MVType == MultiVersionKind::CPUSpecific;

if (CausesMV && OldFD &&
    checkNonMultiVersionCompatAttributes(S, OldFD, NewFD, MVType))
  return true;

if (checkNonMultiVersionCompatAttributes(S, NewFD, nullptr, MVType))
  return true;

// Only allow transition to MultiVersion if it hasn't been used.
if (OldFD && CausesMV && OldFD->isUsed(false))
  return S.Diag(NewFD->getLocation(), diag::err_multiversion_after_used);

return S.areMultiversionVariantFunctionsCompatible(
    OldFD, NewFD, S.PDiag(diag::err_multiversion_noproto),
    PartialDiagnosticAt(NewFD->getLocation(),
                        S.PDiag(diag::note_multiversioning_caused_here)),
    PartialDiagnosticAt(NewFD->getLocation(),
                        S.PDiag(diag::err_multiversion_doesnt_support)
                            << IsCPUSpecificCPUDispatchMVType),
    PartialDiagnosticAt(NewFD->getLocation(),
                        S.PDiag(diag::err_multiversion_diff)),
    /*TemplatesSupported=*/false,
    /*ConstexprSupported=*/!IsCPUSpecificCPUDispatchMVType,
    /*CLinkageMayDiffer=*/false);
10436}

10438/// Check the validity of a multiversion function declaration that is the
10439/// first of its kind. Also sets the multiversion'ness' of the function itself.
10440///
10441/// This sets NewFD->isInvalidDecl() to true if there was an error.
10442///
10443/// Returns true if there was an error, false otherwise.
10444static bool CheckMultiVersionFirstFunction(Sema &S, FunctionDecl *FD,
                                         MultiVersionKind MVType,
                                         const TargetAttr *TA) {
assert(MVType != MultiVersionKind::None &&((void)0)
       "Function lacks multiversion attribute")((void)0);

// Target only causes MV if it is default, otherwise this is a normal
// function.
if (MVType == MultiVersionKind::Target && !TA->isDefaultVersion())
  return false;

if (MVType == MultiVersionKind::Target && CheckMultiVersionValue(S, FD)) {
  FD->setInvalidDecl();
  return true;
}

if (CheckMultiVersionAdditionalRules(S, nullptr, FD, true, MVType)) {
  FD->setInvalidDecl();
  return true;
}

FD->setIsMultiVersion();
return false;
10467}

10469static bool PreviousDeclsHaveMultiVersionAttribute(const FunctionDecl *FD) {
for (const Decl *D = FD->getPreviousDecl(); D; D = D->getPreviousDecl()) {
  if (D->getAsFunction()->getMultiVersionKind() != MultiVersionKind::None)
    return true;
}

return false;
10476}

10478static bool CheckTargetCausesMultiVersioning(
  Sema &S, FunctionDecl *OldFD, FunctionDecl *NewFD, const TargetAttr *NewTA,
  bool &Redeclaration, NamedDecl *&OldDecl, bool &MergeTypeWithPrevious,
  LookupResult &Previous) {
const auto *OldTA = OldFD->getAttr<TargetAttr>();
ParsedTargetAttr NewParsed = NewTA->parse();
// Sort order doesn't matter, it just needs to be consistent.
llvm::sort(NewParsed.Features);

// If the old decl is NOT MultiVersioned yet, and we don't cause that
// to change, this is a simple redeclaration.
if (!NewTA->isDefaultVersion() &&
    (!OldTA || OldTA->getFeaturesStr() == NewTA->getFeaturesStr()))
  return false;

// Otherwise, this decl causes MultiVersioning.
if (!S.getASTContext().getTargetInfo().supportsMultiVersioning()) {
  S.Diag(NewFD->getLocation(), diag::err_multiversion_not_supported);
  S.Diag(OldFD->getLocation(), diag::note_previous_declaration);
  NewFD->setInvalidDecl();
  return true;
}

if (CheckMultiVersionAdditionalRules(S, OldFD, NewFD, true,
                                     MultiVersionKind::Target)) {
  NewFD->setInvalidDecl();
  return true;
}

if (CheckMultiVersionValue(S, NewFD)) {
  NewFD->setInvalidDecl();
  return true;
}

// If this is 'default', permit the forward declaration.
if (!OldFD->isMultiVersion() && !OldTA && NewTA->isDefaultVersion()) {
  Redeclaration = true;
  OldDecl = OldFD;
  OldFD->setIsMultiVersion();
  NewFD->setIsMultiVersion();
  return false;
}

if (CheckMultiVersionValue(S, OldFD)) {
  S.Diag(NewFD->getLocation(), diag::note_multiversioning_caused_here);
  NewFD->setInvalidDecl();
  return true;
}

ParsedTargetAttr OldParsed = OldTA->parse(std::less<std::string>());

if (OldParsed == NewParsed) {
  S.Diag(NewFD->getLocation(), diag::err_multiversion_duplicate);
  S.Diag(OldFD->getLocation(), diag::note_previous_declaration);
  NewFD->setInvalidDecl();
  return true;
}

for (const auto *FD : OldFD->redecls()) {
  const auto *CurTA = FD->getAttr<TargetAttr>();
  // We allow forward declarations before ANY multiversioning attributes, but
  // nothing after the fact.
  if (PreviousDeclsHaveMultiVersionAttribute(FD) &&
      (!CurTA || CurTA->isInherited())) {
    S.Diag(FD->getLocation(), diag::err_multiversion_required_in_redecl)
        << 0;
    S.Diag(NewFD->getLocation(), diag::note_multiversioning_caused_here);
    NewFD->setInvalidDecl();
    return true;
  }
}

OldFD->setIsMultiVersion();
NewFD->setIsMultiVersion();
Redeclaration = false;
MergeTypeWithPrevious = false;
OldDecl = nullptr;
Previous.clear();
return false;
10557}

10559/// Check the validity of a new function declaration being added to an existing
10560/// multiversioned declaration collection.
10561static bool CheckMultiVersionAdditionalDecl(
  Sema &S, FunctionDecl *OldFD, FunctionDecl *NewFD,
  MultiVersionKind NewMVType, const TargetAttr *NewTA,
  const CPUDispatchAttr *NewCPUDisp, const CPUSpecificAttr *NewCPUSpec,
  bool &Redeclaration, NamedDecl *&OldDecl, bool &MergeTypeWithPrevious,
  LookupResult &Previous) {

MultiVersionKind OldMVType = OldFD->getMultiVersionKind();
// Disallow mixing of multiversioning types.
if ((OldMVType == MultiVersionKind::Target &&
     NewMVType != MultiVersionKind::Target) ||
    (NewMVType == MultiVersionKind::Target &&
     OldMVType != MultiVersionKind::Target)) {
  S.Diag(NewFD->getLocation(), diag::err_multiversion_types_mixed);
  S.Diag(OldFD->getLocation(), diag::note_previous_declaration);
  NewFD->setInvalidDecl();
  return true;
}

ParsedTargetAttr NewParsed;
if (NewTA) {
  NewParsed = NewTA->parse();
  llvm::sort(NewParsed.Features);
}

bool UseMemberUsingDeclRules =
    S.CurContext->isRecord() && !NewFD->getFriendObjectKind();

// Next, check ALL non-overloads to see if this is a redeclaration of a
// previous member of the MultiVersion set.
for (NamedDecl *ND : Previous) {
  FunctionDecl *CurFD = ND->getAsFunction();
  if (!CurFD)
    continue;
  if (S.IsOverload(NewFD, CurFD, UseMemberUsingDeclRules))
    continue;

  if (NewMVType == MultiVersionKind::Target) {
    const auto *CurTA = CurFD->getAttr<TargetAttr>();
    if (CurTA->getFeaturesStr() == NewTA->getFeaturesStr()) {
      NewFD->setIsMultiVersion();
      Redeclaration = true;
      OldDecl = ND;
      return false;
    }

    ParsedTargetAttr CurParsed = CurTA->parse(std::less<std::string>());
    if (CurParsed == NewParsed) {
      S.Diag(NewFD->getLocation(), diag::err_multiversion_duplicate);
      S.Diag(CurFD->getLocation(), diag::note_previous_declaration);
      NewFD->setInvalidDecl();
      return true;
    }
  } else {
    const auto *CurCPUSpec = CurFD->getAttr<CPUSpecificAttr>();
    const auto *CurCPUDisp = CurFD->getAttr<CPUDispatchAttr>();
    // Handle CPUDispatch/CPUSpecific versions.
    // Only 1 CPUDispatch function is allowed, this will make it go through
    // the redeclaration errors.
    if (NewMVType == MultiVersionKind::CPUDispatch &&
        CurFD->hasAttr<CPUDispatchAttr>()) {
      if (CurCPUDisp->cpus_size() == NewCPUDisp->cpus_size() &&
          std::equal(
              CurCPUDisp->cpus_begin(), CurCPUDisp->cpus_end(),
              NewCPUDisp->cpus_begin(),
              [](const IdentifierInfo *Cur, const IdentifierInfo *New) {
                return Cur->getName() == New->getName();
              })) {
        NewFD->setIsMultiVersion();
        Redeclaration = true;
        OldDecl = ND;
        return false;
      }

      // If the declarations don't match, this is an error condition.
      S.Diag(NewFD->getLocation(), diag::err_cpu_dispatch_mismatch);
      S.Diag(CurFD->getLocation(), diag::note_previous_declaration);
      NewFD->setInvalidDecl();
      return true;
    }
    if (NewMVType == MultiVersionKind::CPUSpecific && CurCPUSpec) {

      if (CurCPUSpec->cpus_size() == NewCPUSpec->cpus_size() &&
          std::equal(
              CurCPUSpec->cpus_begin(), CurCPUSpec->cpus_end(),
              NewCPUSpec->cpus_begin(),
              [](const IdentifierInfo *Cur, const IdentifierInfo *New) {
                return Cur->getName() == New->getName();
              })) {
        NewFD->setIsMultiVersion();
        Redeclaration = true;
        OldDecl = ND;
        return false;
      }

      // Only 1 version of CPUSpecific is allowed for each CPU.
      for (const IdentifierInfo *CurII : CurCPUSpec->cpus()) {
        for (const IdentifierInfo *NewII : NewCPUSpec->cpus()) {
          if (CurII == NewII) {
            S.Diag(NewFD->getLocation(), diag::err_cpu_specific_multiple_defs)
                << NewII;
            S.Diag(CurFD->getLocation(), diag::note_previous_declaration);
            NewFD->setInvalidDecl();
            return true;
          }
        }
      }
    }
    // If the two decls aren't the same MVType, there is no possible error
    // condition.
  }
}

// Else, this is simply a non-redecl case.  Checking the 'value' is only
// necessary in the Target case, since The CPUSpecific/Dispatch cases are
// handled in the attribute adding step.
if (NewMVType == MultiVersionKind::Target &&
    CheckMultiVersionValue(S, NewFD)) {
  NewFD->setInvalidDecl();
  return true;
}

if (CheckMultiVersionAdditionalRules(S, OldFD, NewFD,
                                     !OldFD->isMultiVersion(), NewMVType)) {
  NewFD->setInvalidDecl();
  return true;
}

// Permit forward declarations in the case where these two are compatible.
if (!OldFD->isMultiVersion()) {
  OldFD->setIsMultiVersion();
  NewFD->setIsMultiVersion();
  Redeclaration = true;
  OldDecl = OldFD;
  return false;
}

NewFD->setIsMultiVersion();
Redeclaration = false;
MergeTypeWithPrevious = false;
OldDecl = nullptr;
Previous.clear();
return false;
10704}


10707/// Check the validity of a mulitversion function declaration.
10708/// Also sets the multiversion'ness' of the function itself.
10709///
10710/// This sets NewFD->isInvalidDecl() to true if there was an error.
10711///
10712/// Returns true if there was an error, false otherwise.
10713static bool CheckMultiVersionFunction(Sema &S, FunctionDecl *NewFD,
                                    bool &Redeclaration, NamedDecl *&OldDecl,
                                    bool &MergeTypeWithPrevious,
                                    LookupResult &Previous) {
const auto *NewTA = NewFD->getAttr<TargetAttr>();
const auto *NewCPUDisp = NewFD->getAttr<CPUDispatchAttr>();
const auto *NewCPUSpec = NewFD->getAttr<CPUSpecificAttr>();

// Mixing Multiversioning types is prohibited.
if ((NewTA && NewCPUDisp) || (NewTA && NewCPUSpec) ||
    (NewCPUDisp && NewCPUSpec)) {
  S.Diag(NewFD->getLocation(), diag::err_multiversion_types_mixed);
  NewFD->setInvalidDecl();
  return true;
}

MultiVersionKind  MVType = NewFD->getMultiVersionKind();

// Main isn't allowed to become a multiversion function, however it IS
// permitted to have 'main' be marked with the 'target' optimization hint.
if (NewFD->isMain()) {
  if ((MVType == MultiVersionKind::Target && NewTA->isDefaultVersion()) ||
      MVType == MultiVersionKind::CPUDispatch ||
      MVType == MultiVersionKind::CPUSpecific) {
    S.Diag(NewFD->getLocation(), diag::err_multiversion_not_allowed_on_main);
    NewFD->setInvalidDecl();
    return true;
  }
  return false;
}

if (!OldDecl || !OldDecl->getAsFunction() ||
    OldDecl->getDeclContext()->getRedeclContext() !=
        NewFD->getDeclContext()->getRedeclContext()) {
  // If there's no previous declaration, AND this isn't attempting to cause
  // multiversioning, this isn't an error condition.
  if (MVType == MultiVersionKind::None)
    return false;
  return CheckMultiVersionFirstFunction(S, NewFD, MVType, NewTA);
}

FunctionDecl *OldFD = OldDecl->getAsFunction();

if (!OldFD->isMultiVersion() && MVType == MultiVersionKind::None)
  return false;

if (OldFD->isMultiVersion() && MVType == MultiVersionKind::None) {
  S.Diag(NewFD->getLocation(), diag::err_multiversion_required_in_redecl)
      << (OldFD->getMultiVersionKind() != MultiVersionKind::Target);
  NewFD->setInvalidDecl();
  return true;
}

// Handle the target potentially causes multiversioning case.
if (!OldFD->isMultiVersion() && MVType == MultiVersionKind::Target)
  return CheckTargetCausesMultiVersioning(S, OldFD, NewFD, NewTA,
                                          Redeclaration, OldDecl,
                                          MergeTypeWithPrevious, Previous);

// At this point, we have a multiversion function decl (in OldFD) AND an
// appropriate attribute in the current function decl.  Resolve that these are
// still compatible with previous declarations.
return CheckMultiVersionAdditionalDecl(
    S, OldFD, NewFD, MVType, NewTA, NewCPUDisp, NewCPUSpec, Redeclaration,
    OldDecl, MergeTypeWithPrevious, Previous);
10778}

10780/// Perform semantic checking of a new function declaration.
10781///
10782/// Performs semantic analysis of the new function declaration
10783/// NewFD. This routine performs all semantic checking that does not
10784/// require the actual declarator involved in the declaration, and is
10785/// used both for the declaration of functions as they are parsed
10786/// (called via ActOnDeclarator) and for the declaration of functions
10787/// that have been instantiated via C++ template instantiation (called
10788/// via InstantiateDecl).
10789///
10790/// \param IsMemberSpecialization whether this new function declaration is
10791/// a member specialization (that replaces any definition provided by the
10792/// previous declaration).
10793///
10794/// This sets NewFD->isInvalidDecl() to true if there was an error.
10795///
10796/// \returns true if the function declaration is a redeclaration.
10797bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
                                  LookupResult &Previous,
                                  bool IsMemberSpecialization) {
assert(!NewFD->getReturnType()->isVariablyModifiedType() &&((void)0)
       "Variably modified return types are not handled here")((void)0);

// Determine whether the type of this function should be merged with
// a previous visible declaration. This never happens for functions in C++,
// and always happens in C if the previous declaration was visible.
bool MergeTypeWithPrevious = !getLangOpts().CPlusPlus &&
                             !Previous.isShadowed();

bool Redeclaration = false;
NamedDecl *OldDecl = nullptr;
bool MayNeedOverloadableChecks = false;

// Merge or overload the declaration with an existing declaration of
// the same name, if appropriate.
if (!Previous.empty()) {
  // Determine whether NewFD is an overload of PrevDecl or
  // a declaration that requires merging. If it's an overload,
  // there's no more work to do here; we'll just add the new
  // function to the scope.
  if (!AllowOverloadingOfFunction(Previous, Context, NewFD)) {
    NamedDecl *Candidate = Previous.getRepresentativeDecl();
    if (shouldLinkPossiblyHiddenDecl(Candidate, NewFD)) {
      Redeclaration = true;
      OldDecl = Candidate;
    }
  } else {
    MayNeedOverloadableChecks = true;
    switch (CheckOverload(S, NewFD, Previous, OldDecl,
                          /*NewIsUsingDecl*/ false)) {
    case Ovl_Match:
      Redeclaration = true;
      break;

    case Ovl_NonFunction:
      Redeclaration = true;
      break;

    case Ovl_Overload:
      Redeclaration = false;
      break;
    }
  }
}

// Check for a previous extern "C" declaration with this name.
if (!Redeclaration &&
    checkForConflictWithNonVisibleExternC(*this, NewFD, Previous)) {
  if (!Previous.empty()) {
    // This is an extern "C" declaration with the same name as a previous
    // declaration, and thus redeclares that entity...
    Redeclaration = true;
    OldDecl = Previous.getFoundDecl();
    MergeTypeWithPrevious = false;

    // ... except in the presence of __attribute__((overloadable)).
    if (OldDecl->hasAttr<OverloadableAttr>() ||
        NewFD->hasAttr<OverloadableAttr>()) {
      if (IsOverload(NewFD, cast<FunctionDecl>(OldDecl), false)) {
        MayNeedOverloadableChecks = true;
        Redeclaration = false;
        OldDecl = nullptr;
      }
    }
  }
}

if (CheckMultiVersionFunction(*this, NewFD, Redeclaration, OldDecl,
                              MergeTypeWithPrevious, Previous))
  return Redeclaration;

// PPC MMA non-pointer types are not allowed as function return types.
if (Context.getTargetInfo().getTriple().isPPC64() &&
    CheckPPCMMAType(NewFD->getReturnType(), NewFD->getLocation())) {
  NewFD->setInvalidDecl();
}

// C++11 [dcl.constexpr]p8:
//   A constexpr specifier for a non-static member function that is not
//   a constructor declares that member function to be const.
//
// This needs to be delayed until we know whether this is an out-of-line
// definition of a static member function.
//
// This rule is not present in C++1y, so we produce a backwards
// compatibility warning whenever it happens in C++11.
CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
if (!getLangOpts().CPlusPlus14 && MD && MD->isConstexpr() &&
    !MD->isStatic() && !isa<CXXConstructorDecl>(MD) &&
    !isa<CXXDestructorDecl>(MD) && !MD->getMethodQualifiers().hasConst()) {
  CXXMethodDecl *OldMD = nullptr;
  if (OldDecl)
    OldMD = dyn_cast_or_null<CXXMethodDecl>(OldDecl->getAsFunction());
  if (!OldMD || !OldMD->isStatic()) {
    const FunctionProtoType *FPT =
      MD->getType()->castAs<FunctionProtoType>();
    FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
    EPI.TypeQuals.addConst();
    MD->setType(Context.getFunctionType(FPT->getReturnType(),
                                        FPT->getParamTypes(), EPI));

    // Warn that we did this, if we're not performing template instantiation.
    // In that case, we'll have warned already when the template was defined.
    if (!inTemplateInstantiation()) {
      SourceLocation AddConstLoc;
      if (FunctionTypeLoc FTL = MD->getTypeSourceInfo()->getTypeLoc()
              .IgnoreParens().getAs<FunctionTypeLoc>())
        AddConstLoc = getLocForEndOfToken(FTL.getRParenLoc());

      Diag(MD->getLocation(), diag::warn_cxx14_compat_constexpr_not_const)
        << FixItHint::CreateInsertion(AddConstLoc, " const");
    }
  }
}

if (Redeclaration) {
  // NewFD and OldDecl represent declarations that need to be
  // merged.
  if (MergeFunctionDecl(NewFD, OldDecl, S, MergeTypeWithPrevious)) {
    NewFD->setInvalidDecl();
    return Redeclaration;
  }

  Previous.clear();
  Previous.addDecl(OldDecl);

  if (FunctionTemplateDecl *OldTemplateDecl =
          dyn_cast<FunctionTemplateDecl>(OldDecl)) {
    auto *OldFD = OldTemplateDecl->getTemplatedDecl();
    FunctionTemplateDecl *NewTemplateDecl
      = NewFD->getDescribedFunctionTemplate();
    assert(NewTemplateDecl && "Template/non-template mismatch")((void)0);

    // The call to MergeFunctionDecl above may have created some state in
    // NewTemplateDecl that needs to be merged with OldTemplateDecl before we
    // can add it as a redeclaration.
    NewTemplateDecl->mergePrevDecl(OldTemplateDecl);

    NewFD->setPreviousDeclaration(OldFD);
    if (NewFD->isCXXClassMember()) {
      NewFD->setAccess(OldTemplateDecl->getAccess());
      NewTemplateDecl->setAccess(OldTemplateDecl->getAccess());
    }

    // If this is an explicit specialization of a member that is a function
    // template, mark it as a member specialization.
    if (IsMemberSpecialization &&
        NewTemplateDecl->getInstantiatedFromMemberTemplate()) {
      NewTemplateDecl->setMemberSpecialization();
      assert(OldTemplateDecl->isMemberSpecialization())((void)0);
      // Explicit specializations of a member template do not inherit deleted
      // status from the parent member template that they are specializing.
      if (OldFD->isDeleted()) {
        // FIXME: This assert will not hold in the presence of modules.
        assert(OldFD->getCanonicalDecl() == OldFD)((void)0);
        // FIXME: We need an update record for this AST mutation.
        OldFD->setDeletedAsWritten(false);
      }
    }

  } else {
    if (shouldLinkDependentDeclWithPrevious(NewFD, OldDecl)) {
      auto *OldFD = cast<FunctionDecl>(OldDecl);
      // This needs to happen first so that 'inline' propagates.
      NewFD->setPreviousDeclaration(OldFD);
      if (NewFD->isCXXClassMember())
        NewFD->setAccess(OldFD->getAccess());
    }
  }
} else if (!getLangOpts().CPlusPlus && MayNeedOverloadableChecks &&
           !NewFD->getAttr<OverloadableAttr>()) {
  assert((Previous.empty() ||((void)0)
          llvm::any_of(Previous,((void)0)
                       [](const NamedDecl *ND) {((void)0)
                         return ND->hasAttr<OverloadableAttr>();((void)0)
                       })) &&((void)0)
         "Non-redecls shouldn't happen without overloadable present")((void)0);

  auto OtherUnmarkedIter = llvm::find_if(Previous, [](const NamedDecl *ND) {
    const auto *FD = dyn_cast<FunctionDecl>(ND);
    return FD && !FD->hasAttr<OverloadableAttr>();
  });

  if (OtherUnmarkedIter != Previous.end()) {
    Diag(NewFD->getLocation(),
         diag::err_attribute_overloadable_multiple_unmarked_overloads);
    Diag((*OtherUnmarkedIter)->getLocation(),
         diag::note_attribute_overloadable_prev_overload)
        << false;

    NewFD->addAttr(OverloadableAttr::CreateImplicit(Context));
  }
}

if (LangOpts.OpenMP)
  ActOnFinishedFunctionDefinitionInOpenMPAssumeScope(NewFD);

// Semantic checking for this function declaration (in isolation).

if (getLangOpts().CPlusPlus) {
  // C++-specific checks.
  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(NewFD)) {
    CheckConstructor(Constructor);
  } else if (CXXDestructorDecl *Destructor =
              dyn_cast<CXXDestructorDecl>(NewFD)) {
    CXXRecordDecl *Record = Destructor->getParent();
    QualType ClassType = Context.getTypeDeclType(Record);

    // FIXME: Shouldn't we be able to perform this check even when the class
    // type is dependent? Both gcc and edg can handle that.
    if (!ClassType->isDependentType()) {
      DeclarationName Name
        = Context.DeclarationNames.getCXXDestructorName(
                                      Context.getCanonicalType(ClassType));
      if (NewFD->getDeclName() != Name) {
        Diag(NewFD->getLocation(), diag::err_destructor_name);
        NewFD->setInvalidDecl();
        return Redeclaration;
      }
    }
  } else if (auto *Guide = dyn_cast<CXXDeductionGuideDecl>(NewFD)) {
    if (auto *TD = Guide->getDescribedFunctionTemplate())
      CheckDeductionGuideTemplate(TD);

    // A deduction guide is not on the list of entities that can be
    // explicitly specialized.
    if (Guide->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
      Diag(Guide->getBeginLoc(), diag::err_deduction_guide_specialized)
          << /*explicit specialization*/ 1;
  }

  // Find any virtual functions that this function overrides.
  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(NewFD)) {
    if (!Method->isFunctionTemplateSpecialization() &&
        !Method->getDescribedFunctionTemplate() &&
        Method->isCanonicalDecl()) {
      AddOverriddenMethods(Method->getParent(), Method);
    }
    if (Method->isVirtual() && NewFD->getTrailingRequiresClause())
      // C++2a [class.virtual]p6
      // A virtual method shall not have a requires-clause.
      Diag(NewFD->getTrailingRequiresClause()->getBeginLoc(),
           diag::err_constrained_virtual_method);

    if (Method->isStatic())
      checkThisInStaticMemberFunctionType(Method);
  }

  if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(NewFD))
    ActOnConversionDeclarator(Conversion);

  // Extra checking for C++ overloaded operators (C++ [over.oper]).
  if (NewFD->isOverloadedOperator() &&
      CheckOverloadedOperatorDeclaration(NewFD)) {
    NewFD->setInvalidDecl();
    return Redeclaration;
  }

  // Extra checking for C++0x literal operators (C++0x [over.literal]).
  if (NewFD->getLiteralIdentifier() &&
      CheckLiteralOperatorDeclaration(NewFD)) {
    NewFD->setInvalidDecl();
    return Redeclaration;
  }

  // In C++, check default arguments now that we have merged decls. Unless
  // the lexical context is the class, because in this case this is done
  // during delayed parsing anyway.
  if (!CurContext->isRecord())
    CheckCXXDefaultArguments(NewFD);

  // If this function is declared as being extern "C", then check to see if
  // the function returns a UDT (class, struct, or union type) that is not C
  // compatible, and if it does, warn the user.
  // But, issue any diagnostic on the first declaration only.
  if (Previous.empty() && NewFD->isExternC()) {
    QualType R = NewFD->getReturnType();
    if (R->isIncompleteType() && !R->isVoidType())
      Diag(NewFD->getLocation(), diag::warn_return_value_udt_incomplete)
          << NewFD << R;
    else if (!R.isPODType(Context) && !R->isVoidType() &&
             !R->isObjCObjectPointerType())
      Diag(NewFD->getLocation(), diag::warn_return_value_udt) << NewFD << R;
  }

  // C++1z [dcl.fct]p6:
  //   [...] whether the function has a non-throwing exception-specification
  //   [is] part of the function type
  //
  // This results in an ABI break between C++14 and C++17 for functions whose
  // declared type includes an exception-specification in a parameter or
  // return type. (Exception specifications on the function itself are OK in
  // most cases, and exception specifications are not permitted in most other
  // contexts where they could make it into a mangling.)
  if (!getLangOpts().CPlusPlus17 && !NewFD->getPrimaryTemplate()) {
    auto HasNoexcept = [&](QualType T) -> bool {
      // Strip off declarator chunks that could be between us and a function
      // type. We don't need to look far, exception specifications are very
      // restricted prior to C++17.
      if (auto *RT = T->getAs<ReferenceType>())
        T = RT->getPointeeType();
      else if (T->isAnyPointerType())
        T = T->getPointeeType();
      else if (auto *MPT = T->getAs<MemberPointerType>())
        T = MPT->getPointeeType();
      if (auto *FPT = T->getAs<FunctionProtoType>())
        if (FPT->isNothrow())
          return true;
      return false;
    };

    auto *FPT = NewFD->getType()->castAs<FunctionProtoType>();
    bool AnyNoexcept = HasNoexcept(FPT->getReturnType());
    for (QualType T : FPT->param_types())
      AnyNoexcept |= HasNoexcept(T);
    if (AnyNoexcept)
      Diag(NewFD->getLocation(),
           diag::warn_cxx17_compat_exception_spec_in_signature)
          << NewFD;
  }

  if (!Redeclaration && LangOpts.CUDA)
    checkCUDATargetOverload(NewFD, Previous);
}
return Redeclaration;
11125}

11127void Sema::CheckMain(FunctionDecl* FD, const DeclSpec& DS) {
// C++11 [basic.start.main]p3:
//   A program that [...] declares main to be inline, static or
//   constexpr is ill-formed.
// C11 6.7.4p4:  In a hosted environment, no function specifier(s) shall
//   appear in a declaration of main.
// static main is not an error under C99, but we should warn about it.
// We accept _Noreturn main as an extension.
if (FD->getStorageClass() == SC_Static)
  Diag(DS.getStorageClassSpecLoc(), getLangOpts().CPlusPlus
       ? diag::err_static_main : diag::warn_static_main)
    << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
if (FD->isInlineSpecified())
  Diag(DS.getInlineSpecLoc(), diag::err_inline_main)
    << FixItHint::CreateRemoval(DS.getInlineSpecLoc());
if (DS.isNoreturnSpecified()) {
  SourceLocation NoreturnLoc = DS.getNoreturnSpecLoc();
  SourceRange NoreturnRange(NoreturnLoc, getLocForEndOfToken(NoreturnLoc));
  Diag(NoreturnLoc, diag::ext_noreturn_main);
  Diag(NoreturnLoc, diag::note_main_remove_noreturn)
    << FixItHint::CreateRemoval(NoreturnRange);
}
if (FD->isConstexpr()) {
  Diag(DS.getConstexprSpecLoc(), diag::err_constexpr_main)
      << FD->isConsteval()
      << FixItHint::CreateRemoval(DS.getConstexprSpecLoc());
  FD->setConstexprKind(ConstexprSpecKind::Unspecified);
}

if (getLangOpts().OpenCL) {
  Diag(FD->getLocation(), diag::err_opencl_no_main)
      << FD->hasAttr<OpenCLKernelAttr>();
  FD->setInvalidDecl();
  return;
}

QualType T = FD->getType();
assert(T->isFunctionType() && "function decl is not of function type")((void)0);
const FunctionType* FT = T->castAs<FunctionType>();

// Set default calling convention for main()
if (FT->getCallConv() != CC_C) {
  FT = Context.adjustFunctionType(FT, FT->getExtInfo().withCallingConv(CC_C));
  FD->setType(QualType(FT, 0));
  T = Context.getCanonicalType(FD->getType());
}

if (getLangOpts().GNUMode && !getLangOpts().CPlusPlus) {
  // In C with GNU extensions we allow main() to have non-integer return
  // type, but we should warn about the extension, and we disable the
  // implicit-return-zero rule.

  // GCC in C mode accepts qualified 'int'.
  if (Context.hasSameUnqualifiedType(FT->getReturnType(), Context.IntTy))
    FD->setHasImplicitReturnZero(true);
  else {
    Diag(FD->getTypeSpecStartLoc(), diag::ext_main_returns_nonint);
    SourceRange RTRange = FD->getReturnTypeSourceRange();
    if (RTRange.isValid())
      Diag(RTRange.getBegin(), diag::note_main_change_return_type)
          << FixItHint::CreateReplacement(RTRange, "int");
  }
} else {
  // In C and C++, main magically returns 0 if you fall off the end;
  // set the flag which tells us that.
  // This is C++ [basic.start.main]p5 and C99 5.1.2.2.3.

  // All the standards say that main() should return 'int'.
  if (Context.hasSameType(FT->getReturnType(), Context.IntTy))
    FD->setHasImplicitReturnZero(true);
  else {
    // Otherwise, this is just a flat-out error.
    SourceRange RTRange = FD->getReturnTypeSourceRange();
    Diag(FD->getTypeSpecStartLoc(), diag::err_main_returns_nonint)
        << (RTRange.isValid() ? FixItHint::CreateReplacement(RTRange, "int")
                              : FixItHint());
    FD->setInvalidDecl(true);
  }
}

// Treat protoless main() as nullary.
if (isa<FunctionNoProtoType>(FT)) return;

const FunctionProtoType* FTP = cast<const FunctionProtoType>(FT);
unsigned nparams = FTP->getNumParams();
assert(FD->getNumParams() == nparams)((void)0);

bool HasExtraParameters = (nparams > 3);

if (FTP->isVariadic()) {
  Diag(FD->getLocation(), diag::ext_variadic_main);
  // FIXME: if we had information about the location of the ellipsis, we
  // could add a FixIt hint to remove it as a parameter.
}

// Darwin passes an undocumented fourth argument of type char**.  If
// other platforms start sprouting these, the logic below will start
// getting shifty.
if (nparams == 4 && Context.getTargetInfo().getTriple().isOSDarwin())
  HasExtraParameters = false;

if (HasExtraParameters) {
  Diag(FD->getLocation(), diag::err_main_surplus_args) << nparams;
  FD->setInvalidDecl(true);
  nparams = 3;
}

// FIXME: a lot of the following diagnostics would be improved
// if we had some location information about types.

QualType CharPP =
  Context.getPointerType(Context.getPointerType(Context.CharTy));
QualType Expected[] = { Context.IntTy, CharPP, CharPP, CharPP };

for (unsigned i = 0; i < nparams; ++i) {
  QualType AT = FTP->getParamType(i);

  bool mismatch = true;

  if (Context.hasSameUnqualifiedType(AT, Expected[i]))
    mismatch = false;
  else if (Expected[i] == CharPP) {
    // As an extension, the following forms are okay:
    //   char const **
    //   char const * const *
    //   char * const *

    QualifierCollector qs;
    const PointerType* PT;
    if ((PT = qs.strip(AT)->getAs<PointerType>()) &&
        (PT = qs.strip(PT->getPointeeType())->getAs<PointerType>()) &&
        Context.hasSameType(QualType(qs.strip(PT->getPointeeType()), 0),
                            Context.CharTy)) {
      qs.removeConst();
      mismatch = !qs.empty();
    }
  }

  if (mismatch) {
    Diag(FD->getLocation(), diag::err_main_arg_wrong) << i << Expected[i];
    // TODO: suggest replacing given type with expected type
    FD->setInvalidDecl(true);
  }
}

if (nparams == 1 && !FD->isInvalidDecl()) {
  Diag(FD->getLocation(), diag::warn_main_one_arg);
}

if (!FD->isInvalidDecl() && FD->getDescribedFunctionTemplate()) {
  Diag(FD->getLocation(), diag::err_mainlike_template_decl) << FD;
  FD->setInvalidDecl();
}
11280}

11282static bool isDefaultStdCall(FunctionDecl *FD, Sema &S) {

// Default calling convention for main and wmain is __cdecl
if (FD->getName() == "main" || FD->getName() == "wmain")
  return false;

// Default calling convention for MinGW is __cdecl
const llvm::Triple &T = S.Context.getTargetInfo().getTriple();
if (T.isWindowsGNUEnvironment())
  return false;

// Default calling convention for WinMain, wWinMain and DllMain
// is __stdcall on 32 bit Windows
if (T.isOSWindows() && T.getArch() == llvm::Triple::x86)
  return true;

return false;
11299}

11301void Sema::CheckMSVCRTEntryPoint(FunctionDecl *FD) {
QualType T = FD->getType();
assert(T->isFunctionType() && "function decl is not of function type")((void)0);
const FunctionType *FT = T->castAs<FunctionType>();

// Set an implicit return of 'zero' if the function can return some integral,
// enumeration, pointer or nullptr type.
if (FT->getReturnType()->isIntegralOrEnumerationType() ||
    FT->getReturnType()->isAnyPointerType() ||
    FT->getReturnType()->isNullPtrType())
  // DllMain is exempt because a return value of zero means it failed.
  if (FD->getName() != "DllMain")
    FD->setHasImplicitReturnZero(true);

// Explicity specified calling conventions are applied to MSVC entry points
if (!hasExplicitCallingConv(T)) {
  if (isDefaultStdCall(FD, *this)) {
    if (FT->getCallConv() != CC_X86StdCall) {
      FT = Context.adjustFunctionType(
          FT, FT->getExtInfo().withCallingConv(CC_X86StdCall));
      FD->setType(QualType(FT, 0));
    }
  } else if (FT->getCallConv() != CC_C) {
    FT = Context.adjustFunctionType(FT,
                                    FT->getExtInfo().withCallingConv(CC_C));
    FD->setType(QualType(FT, 0));
  }
}

if (!FD->isInvalidDecl() && FD->getDescribedFunctionTemplate()) {
  Diag(FD->getLocation(), diag::err_mainlike_template_decl) << FD;
  FD->setInvalidDecl();
}
11334}

11336bool Sema::CheckForConstantInitializer(Expr *Init, QualType DclT) {
// FIXME: Need strict checking.  In C89, we need to check for
// any assignment, increment, decrement, function-calls, or
// commas outside of a sizeof.  In C99, it's the same list,
// except that the aforementioned are allowed in unevaluated
// expressions.  Everything else falls under the
// "may accept other forms of constant expressions" exception.
//
// Regular C++ code will not end up here (exceptions: language extensions,
// OpenCL C++ etc), so the constant expression rules there don't matter.
if (Init->isValueDependent()) {
  assert(Init->containsErrors() &&((void)0)
         "Dependent code should only occur in error-recovery path.")((void)0);
  return true;
}
const Expr *Culprit;
if (Init->isConstantInitializer(Context, false, &Culprit))
  return false;
Diag(Culprit->getExprLoc(), diag::err_init_element_not_constant)
  << Culprit->getSourceRange();
return true;
11357}

11359namespace {
// Visits an initialization expression to see if OrigDecl is evaluated in
// its own initialization and throws a warning if it does.
class SelfReferenceChecker
    : public EvaluatedExprVisitor<SelfReferenceChecker> {
  Sema &S;
  Decl *OrigDecl;
  bool isRecordType;
  bool isPODType;
  bool isReferenceType;

  bool isInitList;
  llvm::SmallVector<unsigned, 4> InitFieldIndex;

public:
  typedef EvaluatedExprVisitor<SelfReferenceChecker> Inherited;

  SelfReferenceChecker(Sema &S, Decl *OrigDecl) : Inherited(S.Context),
                                                  S(S), OrigDecl(OrigDecl) {
    isPODType = false;
    isRecordType = false;
    isReferenceType = false;
    isInitList = false;
    if (ValueDecl *VD = dyn_cast<ValueDecl>(OrigDecl)) {
      isPODType = VD->getType().isPODType(S.Context);
      isRecordType = VD->getType()->isRecordType();
      isReferenceType = VD->getType()->isReferenceType();
    }
  }

  // For most expressions, just call the visitor.  For initializer lists,
  // track the index of the field being initialized since fields are
  // initialized in order allowing use of previously initialized fields.
  void CheckExpr(Expr *E) {
    InitListExpr *InitList = dyn_cast<InitListExpr>(E);
    if (!InitList) {
      Visit(E);
      return;
    }

    // Track and increment the index here.
    isInitList = true;
    InitFieldIndex.push_back(0);
    for (auto Child : InitList->children()) {
      CheckExpr(cast<Expr>(Child));
      ++InitFieldIndex.back();
    }
    InitFieldIndex.pop_back();
  }

  // Returns true if MemberExpr is checked and no further checking is needed.
  // Returns false if additional checking is required.
  bool CheckInitListMemberExpr(MemberExpr *E, bool CheckReference) {
    llvm::SmallVector<FieldDecl*, 4> Fields;
    Expr *Base = E;
    bool ReferenceField = false;

    // Get the field members used.
    while (MemberExpr *ME = dyn_cast<MemberExpr>(Base)) {
      FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
      if (!FD)
        return false;
      Fields.push_back(FD);
      if (FD->getType()->isReferenceType())
        ReferenceField = true;
      Base = ME->getBase()->IgnoreParenImpCasts();
    }

    // Keep checking only if the base Decl is the same.
    DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base);
    if (!DRE || DRE->getDecl() != OrigDecl)
      return false;

    // A reference field can be bound to an unininitialized field.
    if (CheckReference && !ReferenceField)
      return true;

    // Convert FieldDecls to their index number.
    llvm::SmallVector<unsigned, 4> UsedFieldIndex;
    for (const FieldDecl *I : llvm::reverse(Fields))
      UsedFieldIndex.push_back(I->getFieldIndex());

    // See if a warning is needed by checking the first difference in index
    // numbers.  If field being used has index less than the field being
    // initialized, then the use is safe.
    for (auto UsedIter = UsedFieldIndex.begin(),
              UsedEnd = UsedFieldIndex.end(),
              OrigIter = InitFieldIndex.begin(),
              OrigEnd = InitFieldIndex.end();
         UsedIter != UsedEnd && OrigIter != OrigEnd; ++UsedIter, ++OrigIter) {
      if (*UsedIter < *OrigIter)
        return true;
      if (*UsedIter > *OrigIter)
        break;
    }

    // TODO: Add a different warning which will print the field names.
    HandleDeclRefExpr(DRE);
    return true;
  }

  // For most expressions, the cast is directly above the DeclRefExpr.
  // For conditional operators, the cast can be outside the conditional
  // operator if both expressions are DeclRefExpr's.
  void HandleValue(Expr *E) {
    E = E->IgnoreParens();
    if (DeclRefExpr* DRE = dyn_cast<DeclRefExpr>(E)) {
      HandleDeclRefExpr(DRE);
      return;
    }

    if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
      Visit(CO->getCond());
      HandleValue(CO->getTrueExpr());
      HandleValue(CO->getFalseExpr());
      return;
    }

    if (BinaryConditionalOperator *BCO =
            dyn_cast<BinaryConditionalOperator>(E)) {
      Visit(BCO->getCond());
      HandleValue(BCO->getFalseExpr());
      return;
    }

    if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
      HandleValue(OVE->getSourceExpr());
      return;
    }

    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
      if (BO->getOpcode() == BO_Comma) {
        Visit(BO->getLHS());
        HandleValue(BO->getRHS());
        return;
      }
    }

    if (isa<MemberExpr>(E)) {
      if (isInitList) {
        if (CheckInitListMemberExpr(cast<MemberExpr>(E),
                                    false /*CheckReference*/))
          return;
      }

      Expr *Base = E->IgnoreParenImpCasts();
      while (MemberExpr *ME = dyn_cast<MemberExpr>(Base)) {
        // Check for static member variables and don't warn on them.
        if (!isa<FieldDecl>(ME->getMemberDecl()))
          return;
        Base = ME->getBase()->IgnoreParenImpCasts();
      }
      if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base))
        HandleDeclRefExpr(DRE);
      return;
    }

    Visit(E);
  }

  // Reference types not handled in HandleValue are handled here since all
  // uses of references are bad, not just r-value uses.
  void VisitDeclRefExpr(DeclRefExpr *E) {
    if (isReferenceType)
      HandleDeclRefExpr(E);
  }

  void VisitImplicitCastExpr(ImplicitCastExpr *E) {
    if (E->getCastKind() == CK_LValueToRValue) {
      HandleValue(E->getSubExpr());
      return;
    }

    Inherited::VisitImplicitCastExpr(E);
  }

  void VisitMemberExpr(MemberExpr *E) {
    if (isInitList) {
      if (CheckInitListMemberExpr(E, true /*CheckReference*/))
        return;
    }

    // Don't warn on arrays since they can be treated as pointers.
    if (E->getType()->canDecayToPointerType()) return;

    // Warn when a non-static method call is followed by non-static member
    // field accesses, which is followed by a DeclRefExpr.
    CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl());
    bool Warn = (MD && !MD->isStatic());
    Expr *Base = E->getBase()->IgnoreParenImpCasts();
    while (MemberExpr *ME = dyn_cast<MemberExpr>(Base)) {
      if (!isa<FieldDecl>(ME->getMemberDecl()))
        Warn = false;
      Base = ME->getBase()->IgnoreParenImpCasts();
    }

    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
      if (Warn)
        HandleDeclRefExpr(DRE);
      return;
    }

    // The base of a MemberExpr is not a MemberExpr or a DeclRefExpr.
    // Visit that expression.
    Visit(Base);
  }

  void VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
    Expr *Callee = E->getCallee();

    if (isa<UnresolvedLookupExpr>(Callee))
      return Inherited::VisitCXXOperatorCallExpr(E);

    Visit(Callee);
    for (auto Arg: E->arguments())
      HandleValue(Arg->IgnoreParenImpCasts());
  }

  void VisitUnaryOperator(UnaryOperator *E) {
    // For POD record types, addresses of its own members are well-defined.
    if (E->getOpcode() == UO_AddrOf && isRecordType &&
        isa<MemberExpr>(E->getSubExpr()->IgnoreParens())) {
      if (!isPODType)
        HandleValue(E->getSubExpr());
      return;
    }

    if (E->isIncrementDecrementOp()) {
      HandleValue(E->getSubExpr());
      return;
    }

    Inherited::VisitUnaryOperator(E);
  }

  void VisitObjCMessageExpr(ObjCMessageExpr *E) {}

  void VisitCXXConstructExpr(CXXConstructExpr *E) {
    if (E->getConstructor()->isCopyConstructor()) {
      Expr *ArgExpr = E->getArg(0);
      if (InitListExpr *ILE = dyn_cast<InitListExpr>(ArgExpr))
        if (ILE->getNumInits() == 1)
          ArgExpr = ILE->getInit(0);
      if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
        if (ICE->getCastKind() == CK_NoOp)
          ArgExpr = ICE->getSubExpr();
      HandleValue(ArgExpr);
      return;
    }
    Inherited::VisitCXXConstructExpr(E);
  }

  void VisitCallExpr(CallExpr *E) {
    // Treat std::move as a use.
    if (E->isCallToStdMove()) {
      HandleValue(E->getArg(0));
      return;
    }

    Inherited::VisitCallExpr(E);
  }

  void VisitBinaryOperator(BinaryOperator *E) {
    if (E->isCompoundAssignmentOp()) {
      HandleValue(E->getLHS());
      Visit(E->getRHS());
      return;
    }

    Inherited::VisitBinaryOperator(E);
  }

  // A custom visitor for BinaryConditionalOperator is needed because the
  // regular visitor would check the condition and true expression separately
  // but both point to the same place giving duplicate diagnostics.
  void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
    Visit(E->getCond());
    Visit(E->getFalseExpr());
  }

  void HandleDeclRefExpr(DeclRefExpr *DRE) {
    Decl* ReferenceDecl = DRE->getDecl();
    if (OrigDecl != ReferenceDecl) return;
    unsigned diag;
    if (isReferenceType) {
      diag = diag::warn_uninit_self_reference_in_reference_init;
    } else if (cast<VarDecl>(OrigDecl)->isStaticLocal()) {
      diag = diag::warn_static_self_reference_in_init;
    } else if (isa<TranslationUnitDecl>(OrigDecl->getDeclContext()) ||
               isa<NamespaceDecl>(OrigDecl->getDeclContext()) ||
               DRE->getDecl()->getType()->isRecordType()) {
      diag = diag::warn_uninit_self_reference_in_init;
    } else {
      // Local variables will be handled by the CFG analysis.
      return;
    }

    S.DiagRuntimeBehavior(DRE->getBeginLoc(), DRE,
                          S.PDiag(diag)
                              << DRE->getDecl() << OrigDecl->getLocation()
                              << DRE->getSourceRange());
  }
};

/// CheckSelfReference - Warns if OrigDecl is used in expression E.
static void CheckSelfReference(Sema &S, Decl* OrigDecl, Expr *E,
                               bool DirectInit) {
  // Parameters arguments are occassionially constructed with itself,
  // for instance, in recursive functions.  Skip them.
  if (isa<ParmVarDecl>(OrigDecl))
    return;

  E = E->IgnoreParens();

  // Skip checking T a = a where T is not a record or reference type.
  // Doing so is a way to silence uninitialized warnings.
  if (!DirectInit && !cast<VarDecl>(OrigDecl)->getType()->isRecordType())
    if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
      if (ICE->getCastKind() == CK_LValueToRValue)
        if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr()))
          if (DRE->getDecl() == OrigDecl)
            return;

  SelfReferenceChecker(S, OrigDecl).CheckExpr(E);
}
11684} // end anonymous namespace

11686namespace {
// Simple wrapper to add the name of a variable or (if no variable is
// available) a DeclarationName into a diagnostic.
struct VarDeclOrName {
  VarDecl *VDecl;
  DeclarationName Name;

  friend const Sema::SemaDiagnosticBuilder &
  operator<<(const Sema::SemaDiagnosticBuilder &Diag, VarDeclOrName VN) {
    return VN.VDecl ? Diag << VN.VDecl : Diag << VN.Name;
  }
};
11698} // end anonymous namespace

11700QualType Sema::deduceVarTypeFromInitializer(VarDecl *VDecl,
                                          DeclarationName Name, QualType Type,
                                          TypeSourceInfo *TSI,
                                          SourceRange Range, bool DirectInit,
                                          Expr *Init) {
bool IsInitCapture = !VDecl;
assert((!VDecl || !VDecl->isInitCapture()) &&((void)0)
       "init captures are expected to be deduced prior to initialization")((void)0);

VarDeclOrName VN{VDecl, Name};

DeducedType *Deduced = Type->getContainedDeducedType();
assert(Deduced && "deduceVarTypeFromInitializer for non-deduced type")((void)0);

// C++11 [dcl.spec.auto]p3
if (!Init) {
  assert(VDecl && "no init for init capture deduction?")((void)0);

  // Except for class argument deduction, and then for an initializing
  // declaration only, i.e. no static at class scope or extern.
  if (!isa<DeducedTemplateSpecializationType>(Deduced) ||
      VDecl->hasExternalStorage() ||
      VDecl->isStaticDataMember()) {
    Diag(VDecl->getLocation(), diag::err_auto_var_requires_init)
      << VDecl->getDeclName() << Type;
    return QualType();
  }
}

ArrayRef<Expr*> DeduceInits;
if (Init)
  DeduceInits = Init;

if (DirectInit) {
  if (auto *PL = dyn_cast_or_null<ParenListExpr>(Init))
    DeduceInits = PL->exprs();
}

if (isa<DeducedTemplateSpecializationType>(Deduced)) {
  assert(VDecl && "non-auto type for init capture deduction?")((void)0);
  InitializedEntity Entity = InitializedEntity::InitializeVariable(VDecl);
  InitializationKind Kind = InitializationKind::CreateForInit(
      VDecl->getLocation(), DirectInit, Init);
  // FIXME: Initialization should not be taking a mutable list of inits.
  SmallVector<Expr*, 8> InitsCopy(DeduceInits.begin(), DeduceInits.end());
  return DeduceTemplateSpecializationFromInitializer(TSI, Entity, Kind,
                                                     InitsCopy);
}

if (DirectInit) {
  if (auto *IL = dyn_cast<InitListExpr>(Init))
    DeduceInits = IL->inits();
}

// Deduction only works if we have exactly one source expression.
if (DeduceInits.empty()) {
  // It isn't possible to write this directly, but it is possible to
  // end up in this situation with "auto x(some_pack...);"
  Diag(Init->getBeginLoc(), IsInitCapture
                                ? diag::err_init_capture_no_expression
                                : diag::err_auto_var_init_no_expression)
      << VN << Type << Range;
  return QualType();
}

if (DeduceInits.size() > 1) {
  Diag(DeduceInits[1]->getBeginLoc(),
       IsInitCapture ? diag::err_init_capture_multiple_expressions
                     : diag::err_auto_var_init_multiple_expressions)
      << VN << Type << Range;
  return QualType();
}

Expr *DeduceInit = DeduceInits[0];
if (DirectInit && isa<InitListExpr>(DeduceInit)) {
  Diag(Init->getBeginLoc(), IsInitCapture
                                ? diag::err_init_capture_paren_braces
                                : diag::err_auto_var_init_paren_braces)
      << isa<InitListExpr>(Init) << VN << Type << Range;
  return QualType();
}

// Expressions default to 'id' when we're in a debugger.
bool DefaultedAnyToId = false;
if (getLangOpts().DebuggerCastResultToId &&
    Init->getType() == Context.UnknownAnyTy && !IsInitCapture) {
  ExprResult Result = forceUnknownAnyToType(Init, Context.getObjCIdType());
  if (Result.isInvalid()) {
    return QualType();
  }
  Init = Result.get();
  DefaultedAnyToId = true;
}

// C++ [dcl.decomp]p1:
//   If the assignment-expression [...] has array type A and no ref-qualifier
//   is present, e has type cv A
if (VDecl && isa<DecompositionDecl>(VDecl) &&
    Context.hasSameUnqualifiedType(Type, Context.getAutoDeductType()) &&
    DeduceInit->getType()->isConstantArrayType())
  return Context.getQualifiedType(DeduceInit->getType(),
                                  Type.getQualifiers());

QualType DeducedType;
if (DeduceAutoType(TSI, DeduceInit, DeducedType) == DAR_Failed) {
  if (!IsInitCapture)
    DiagnoseAutoDeductionFailure(VDecl, DeduceInit);
  else if (isa<InitListExpr>(Init))
    Diag(Range.getBegin(),
         diag::err_init_capture_deduction_failure_from_init_list)
        << VN
        << (DeduceInit->getType().isNull() ? TSI->getType()
                                           : DeduceInit->getType())
        << DeduceInit->getSourceRange();
  else
    Diag(Range.getBegin(), diag::err_init_capture_deduction_failure)
        << VN << TSI->getType()
        << (DeduceInit->getType().isNull() ? TSI->getType()
                                           : DeduceInit->getType())
        << DeduceInit->getSourceRange();
}

// Warn if we deduced 'id'. 'auto' usually implies type-safety, but using
// 'id' instead of a specific object type prevents most of our usual
// checks.
// We only want to warn outside of template instantiations, though:
// inside a template, the 'id' could have come from a parameter.
if (!inTemplateInstantiation() && !DefaultedAnyToId && !IsInitCapture &&
    !DeducedType.isNull() && DeducedType->isObjCIdType()) {
  SourceLocation Loc = TSI->getTypeLoc().getBeginLoc();
  Diag(Loc, diag::warn_auto_var_is_id) << VN << Range;
}

return DeducedType;
11834}

11836bool Sema::DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
                                       Expr *Init) {
assert(!Init || !Init->containsErrors())((void)0);
QualType DeducedType = deduceVarTypeFromInitializer(
    VDecl, VDecl->getDeclName(), VDecl->getType(), VDecl->getTypeSourceInfo(),
    VDecl->getSourceRange(), DirectInit, Init);
if (DeducedType.isNull()) {
  VDecl->setInvalidDecl();
  return true;
}

VDecl->setType(DeducedType);
assert(VDecl->isLinkageValid())((void)0);

// In ARC, infer lifetime.
if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(VDecl))
  VDecl->setInvalidDecl();

if (getLangOpts().OpenCL)
  deduceOpenCLAddressSpace(VDecl);

// If this is a redeclaration, check that the type we just deduced matches
// the previously declared type.
if (VarDecl *Old = VDecl->getPreviousDecl()) {
  // We never need to merge the type, because we cannot form an incomplete
  // array of auto, nor deduce such a type.
  MergeVarDeclTypes(VDecl, Old, /*MergeTypeWithPrevious*/ false);
}

// Check the deduced type is valid for a variable declaration.
CheckVariableDeclarationType(VDecl);
return VDecl->isInvalidDecl();
11868}

11870void Sema::checkNonTrivialCUnionInInitializer(const Expr *Init,
                                            SourceLocation Loc) {
if (auto *EWC = dyn_cast<ExprWithCleanups>(Init))
  Init = EWC->getSubExpr();

if (auto *CE = dyn_cast<ConstantExpr>(Init))
  Init = CE->getSubExpr();

QualType InitType = Init->getType();
assert((InitType.hasNonTrivialToPrimitiveDefaultInitializeCUnion() ||((void)0)
        InitType.hasNonTrivialToPrimitiveCopyCUnion()) &&((void)0)
       "shouldn't be called if type doesn't have a non-trivial C struct")((void)0);
if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
  for (auto I : ILE->inits()) {
    if (!I->getType().hasNonTrivialToPrimitiveDefaultInitializeCUnion() &&
        !I->getType().hasNonTrivialToPrimitiveCopyCUnion())
      continue;
    SourceLocation SL = I->getExprLoc();
    checkNonTrivialCUnionInInitializer(I, SL.isValid() ? SL : Loc);
  }
  return;
}

if (isa<ImplicitValueInitExpr>(Init)) {
  if (InitType.hasNonTrivialToPrimitiveDefaultInitializeCUnion())
    checkNonTrivialCUnion(InitType, Loc, NTCUC_DefaultInitializedObject,
                          NTCUK_Init);
} else {
  // Assume all other explicit initializers involving copying some existing
  // object.
  // TODO: ignore any explicit initializers where we can guarantee
  // copy-elision.
  if (InitType.hasNonTrivialToPrimitiveCopyCUnion())
    checkNonTrivialCUnion(InitType, Loc, NTCUC_CopyInit, NTCUK_Copy);
}
11905}

11907namespace {

11909bool shouldIgnoreForRecordTriviality(const FieldDecl *FD) {
// Ignore unavailable fields. A field can be marked as unavailable explicitly
// in the source code or implicitly by the compiler if it is in a union
// defined in a system header and has non-trivial ObjC ownership
// qualifications. We don't want those fields to participate in determining
// whether the containing union is non-trivial.
return FD->hasAttr<UnavailableAttr>();
11916}

11918struct DiagNonTrivalCUnionDefaultInitializeVisitor
  : DefaultInitializedTypeVisitor<DiagNonTrivalCUnionDefaultInitializeVisitor,
                                  void> {
using Super =
    DefaultInitializedTypeVisitor<DiagNonTrivalCUnionDefaultInitializeVisitor,
                                  void>;

DiagNonTrivalCUnionDefaultInitializeVisitor(
    QualType OrigTy, SourceLocation OrigLoc,
    Sema::NonTrivialCUnionContext UseContext, Sema &S)
    : OrigTy(OrigTy), OrigLoc(OrigLoc), UseContext(UseContext), S(S) {}

void visitWithKind(QualType::PrimitiveDefaultInitializeKind PDIK, QualType QT,
                   const FieldDecl *FD, bool InNonTrivialUnion) {
  if (const auto *AT = S.Context.getAsArrayType(QT))
    return this->asDerived().visit(S.Context.getBaseElementType(AT), FD,
                                   InNonTrivialUnion);
  return Super::visitWithKind(PDIK, QT, FD, InNonTrivialUnion);
}

void visitARCStrong(QualType QT, const FieldDecl *FD,
                    bool InNonTrivialUnion) {
  if (InNonTrivialUnion)
    S.Diag(FD->getLocation(), diag::note_non_trivial_c_union)
        << 1 << 0 << QT << FD->getName();
}

void visitARCWeak(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {
  if (InNonTrivialUnion)
    S.Diag(FD->getLocation(), diag::note_non_trivial_c_union)
        << 1 << 0 << QT << FD->getName();
}

void visitStruct(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {
  const RecordDecl *RD = QT->castAs<RecordType>()->getDecl();
  if (RD->isUnion()) {
    if (OrigLoc.isValid()) {
      bool IsUnion = false;
      if (auto *OrigRD = OrigTy->getAsRecordDecl())
        IsUnion = OrigRD->isUnion();
      S.Diag(OrigLoc, diag::err_non_trivial_c_union_in_invalid_context)
          << 0 << OrigTy << IsUnion << UseContext;
      // Reset OrigLoc so that this diagnostic is emitted only once.
      OrigLoc = SourceLocation();
    }
    InNonTrivialUnion = true;
  }

  if (InNonTrivialUnion)
    S.Diag(RD->getLocation(), diag::note_non_trivial_c_union)
        << 0 << 0 << QT.getUnqualifiedType() << "";

  for (const FieldDecl *FD : RD->fields())
    if (!shouldIgnoreForRecordTriviality(FD))
      asDerived().visit(FD->getType(), FD, InNonTrivialUnion);
}

void visitTrivial(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {}

// The non-trivial C union type or the struct/union type that contains a
// non-trivial C union.
QualType OrigTy;
SourceLocation OrigLoc;
Sema::NonTrivialCUnionContext UseContext;
Sema &S;
11983};

11985struct DiagNonTrivalCUnionDestructedTypeVisitor
  : DestructedTypeVisitor<DiagNonTrivalCUnionDestructedTypeVisitor, void> {
using Super =
    DestructedTypeVisitor<DiagNonTrivalCUnionDestructedTypeVisitor, void>;

DiagNonTrivalCUnionDestructedTypeVisitor(
    QualType OrigTy, SourceLocation OrigLoc,
    Sema::NonTrivialCUnionContext UseContext, Sema &S)
    : OrigTy(OrigTy), OrigLoc(OrigLoc), UseContext(UseContext), S(S) {}

void visitWithKind(QualType::DestructionKind DK, QualType QT,
                   const FieldDecl *FD, bool InNonTrivialUnion) {
  if (const auto *AT = S.Context.getAsArrayType(QT))
    return this->asDerived().visit(S.Context.getBaseElementType(AT), FD,
                                   InNonTrivialUnion);
  return Super::visitWithKind(DK, QT, FD, InNonTrivialUnion);
}

void visitARCStrong(QualType QT, const FieldDecl *FD,
                    bool InNonTrivialUnion) {
  if (InNonTrivialUnion)
    S.Diag(FD->getLocation(), diag::note_non_trivial_c_union)
        << 1 << 1 << QT << FD->getName();
}

void visitARCWeak(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {
  if (InNonTrivialUnion)
    S.Diag(FD->getLocation(), diag::note_non_trivial_c_union)
        << 1 << 1 << QT << FD->getName();
}

void visitStruct(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {
  const RecordDecl *RD = QT->castAs<RecordType>()->getDecl();
  if (RD->isUnion()) {
    if (OrigLoc.isValid()) {
      bool IsUnion = false;
      if (auto *OrigRD = OrigTy->getAsRecordDecl())
        IsUnion = OrigRD->isUnion();
      S.Diag(OrigLoc, diag::err_non_trivial_c_union_in_invalid_context)
          << 1 << OrigTy << IsUnion << UseContext;
      // Reset OrigLoc so that this diagnostic is emitted only once.
      OrigLoc = SourceLocation();
    }
    InNonTrivialUnion = true;
  }

  if (InNonTrivialUnion)
    S.Diag(RD->getLocation(), diag::note_non_trivial_c_union)
        << 0 << 1 << QT.getUnqualifiedType() << "";

  for (const FieldDecl *FD : RD->fields())
    if (!shouldIgnoreForRecordTriviality(FD))
      asDerived().visit(FD->getType(), FD, InNonTrivialUnion);
}

void visitTrivial(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {}
void visitCXXDestructor(QualType QT, const FieldDecl *FD,
                        bool InNonTrivialUnion) {}

// The non-trivial C union type or the struct/union type that contains a
// non-trivial C union.
QualType OrigTy;
SourceLocation OrigLoc;
Sema::NonTrivialCUnionContext UseContext;
Sema &S;
12050};

12052struct DiagNonTrivalCUnionCopyVisitor
  : CopiedTypeVisitor<DiagNonTrivalCUnionCopyVisitor, false, void> {
using Super = CopiedTypeVisitor<DiagNonTrivalCUnionCopyVisitor, false, void>;

DiagNonTrivalCUnionCopyVisitor(QualType OrigTy, SourceLocation OrigLoc,
                               Sema::NonTrivialCUnionContext UseContext,
                               Sema &S)
    : OrigTy(OrigTy), OrigLoc(OrigLoc), UseContext(UseContext), S(S) {}

void visitWithKind(QualType::PrimitiveCopyKind PCK, QualType QT,
                   const FieldDecl *FD, bool InNonTrivialUnion) {
  if (const auto *AT = S.Context.getAsArrayType(QT))
    return this->asDerived().visit(S.Context.getBaseElementType(AT), FD,
                                   InNonTrivialUnion);
  return Super::visitWithKind(PCK, QT, FD, InNonTrivialUnion);
}

void visitARCStrong(QualType QT, const FieldDecl *FD,
                    bool InNonTrivialUnion) {
  if (InNonTrivialUnion)
    S.Diag(FD->getLocation(), diag::note_non_trivial_c_union)
        << 1 << 2 << QT << FD->getName();
}

void visitARCWeak(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {
  if (InNonTrivialUnion)
    S.Diag(FD->getLocation(), diag::note_non_trivial_c_union)
        << 1 << 2 << QT << FD->getName();
}

void visitStruct(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {
  const RecordDecl *RD = QT->castAs<RecordType>()->getDecl();
  if (RD->isUnion()) {
    if (OrigLoc.isValid()) {
      bool IsUnion = false;
      if (auto *OrigRD = OrigTy->getAsRecordDecl())
        IsUnion = OrigRD->isUnion();
      S.Diag(OrigLoc, diag::err_non_trivial_c_union_in_invalid_context)
          << 2 << OrigTy << IsUnion << UseContext;
      // Reset OrigLoc so that this diagnostic is emitted only once.
      OrigLoc = SourceLocation();
    }
    InNonTrivialUnion = true;
  }

  if (InNonTrivialUnion)
    S.Diag(RD->getLocation(), diag::note_non_trivial_c_union)
        << 0 << 2 << QT.getUnqualifiedType() << "";

  for (const FieldDecl *FD : RD->fields())
    if (!shouldIgnoreForRecordTriviality(FD))
      asDerived().visit(FD->getType(), FD, InNonTrivialUnion);
}

void preVisit(QualType::PrimitiveCopyKind PCK, QualType QT,
              const FieldDecl *FD, bool InNonTrivialUnion) {}
void visitTrivial(QualType QT, const FieldDecl *FD, bool InNonTrivialUnion) {}
void visitVolatileTrivial(QualType QT, const FieldDecl *FD,
                          bool InNonTrivialUnion) {}

// The non-trivial C union type or the struct/union type that contains a
// non-trivial C union.
QualType OrigTy;
SourceLocation OrigLoc;
Sema::NonTrivialCUnionContext UseContext;
Sema &S;
12118};

12120} // namespace

12122void Sema::checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
                               NonTrivialCUnionContext UseContext,
                               unsigned NonTrivialKind) {
assert((QT.hasNonTrivialToPrimitiveDefaultInitializeCUnion() ||((void)0)
        QT.hasNonTrivialToPrimitiveDestructCUnion() ||((void)0)
        QT.hasNonTrivialToPrimitiveCopyCUnion()) &&((void)0)
       "shouldn't be called if type doesn't have a non-trivial C union")((void)0);

if ((NonTrivialKind & NTCUK_Init) &&
    QT.hasNonTrivialToPrimitiveDefaultInitializeCUnion())
  DiagNonTrivalCUnionDefaultInitializeVisitor(QT, Loc, UseContext, *this)
      .visit(QT, nullptr, false);
if ((NonTrivialKind & NTCUK_Destruct) &&
    QT.hasNonTrivialToPrimitiveDestructCUnion())
  DiagNonTrivalCUnionDestructedTypeVisitor(QT, Loc, UseContext, *this)
      .visit(QT, nullptr, false);
if ((NonTrivialKind & NTCUK_Copy) && QT.hasNonTrivialToPrimitiveCopyCUnion())
  DiagNonTrivalCUnionCopyVisitor(QT, Loc, UseContext, *this)
      .visit(QT, nullptr, false);
12141}

12143/// AddInitializerToDecl - Adds the initializer Init to the
12144/// declaration dcl. If DirectInit is true, this is C++ direct
12145/// initialization rather than copy initialization.
12146void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
// If there is no declaration, there was an error parsing it.  Just ignore
// the initializer.
if (!RealDecl || RealDecl->isInvalidDecl()) {
  CorrectDelayedTyposInExpr(Init, dyn_cast_or_null<VarDecl>(RealDecl));
  return;
}

if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(RealDecl)) {
  // Pure-specifiers are handled in ActOnPureSpecifier.
  Diag(Method->getLocation(), diag::err_member_function_initialization)
    << Method->getDeclName() << Init->getSourceRange();
  Method->setInvalidDecl();
  return;
}

VarDecl *VDecl = dyn_cast<VarDecl>(RealDecl);
if (!VDecl) {
  assert(!isa<FieldDecl>(RealDecl) && "field init shouldn't get here")((void)0);
  Diag(RealDecl->getLocation(), diag::err_illegal_initializer);
  RealDecl->setInvalidDecl();
  return;
}

// C++11 [decl.spec.auto]p6. Deduce the type which 'auto' stands in for.
if (VDecl->getType()->isUndeducedType()) {
  // Attempt typo correction early so that the type of the init expression can
  // be deduced based on the chosen correction if the original init contains a
  // TypoExpr.
  ExprResult Res = CorrectDelayedTyposInExpr(Init, VDecl);
  if (!Res.isUsable()) {
    // There are unresolved typos in Init, just drop them.
    // FIXME: improve the recovery strategy to preserve the Init.
    RealDecl->setInvalidDecl();
    return;
  }
  if (Res.get()->containsErrors()) {
    // Invalidate the decl as we don't know the type for recovery-expr yet.
    RealDecl->setInvalidDecl();
    VDecl->setInit(Res.get());
    return;
  }
  Init = Res.get();

  if (DeduceVariableDeclarationType(VDecl, DirectInit, Init))
    return;
}

// dllimport cannot be used on variable definitions.
if (VDecl->hasAttr<DLLImportAttr>() && !VDecl->isStaticDataMember()) {
  Diag(VDecl->getLocation(), diag::err_attribute_dllimport_data_definition);
  VDecl->setInvalidDecl();
  return;
}

if (VDecl->isLocalVarDecl() && VDecl->hasExternalStorage()) {
  // C99 6.7.8p5. C++ has no such restriction, but that is a defect.
  Diag(VDecl->getLocation(), diag::err_block_extern_cant_init);
  VDecl->setInvalidDecl();
  return;
}

if (!VDecl->getType()->isDependentType()) {
  // A definition must end up with a complete type, which means it must be
  // complete with the restriction that an array type might be completed by
  // the initializer; note that later code assumes this restriction.
  QualType BaseDeclType = VDecl->getType();
  if (const ArrayType *Array = Context.getAsIncompleteArrayType(BaseDeclType))
    BaseDeclType = Array->getElementType();
  if (RequireCompleteType(VDecl->getLocation(), BaseDeclType,
                          diag::err_typecheck_decl_incomplete_type)) {
    RealDecl->setInvalidDecl();
    return;
  }

  // The variable can not have an abstract class type.
  if (RequireNonAbstractType(VDecl->getLocation(), VDecl->getType(),
                             diag::err_abstract_type_in_decl,
                             AbstractVariableType))
    VDecl->setInvalidDecl();
}

// If adding the initializer will turn this declaration into a definition,
// and we already have a definition for this variable, diagnose or otherwise
// handle the situation.
if (VarDecl *Def = VDecl->getDefinition())
  if (Def != VDecl &&
      (!VDecl->isStaticDataMember() || VDecl->isOutOfLine()) &&
      !VDecl->isThisDeclarationADemotedDefinition() &&
      checkVarDeclRedefinition(Def, VDecl))
    return;

if (getLangOpts().CPlusPlus) {
  // C++ [class.static.data]p4
  //   If a static data member is of const integral or const
  //   enumeration type, its declaration in the class definition can
  //   specify a constant-initializer which shall be an integral
  //   constant expression (5.19). In that case, the member can appear
  //   in integral constant expressions. The member shall still be
  //   defined in a namespace scope if it is used in the program and the
  //   namespace scope definition shall not contain an initializer.
  //
  // We already performed a redefinition check above, but for static
  // data members we also need to check whether there was an in-class
  // declaration with an initializer.
  if (VDecl->isStaticDataMember() && VDecl->getCanonicalDecl()->hasInit()) {
    Diag(Init->getExprLoc(), diag::err_static_data_member_reinitialization)
        << VDecl->getDeclName();
    Diag(VDecl->getCanonicalDecl()->getInit()->getExprLoc(),
         diag::note_previous_initializer)
        << 0;
    return;
  }

  if (VDecl->hasLocalStorage())
    setFunctionHasBranchProtectedScope();

  if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer)) {
    VDecl->setInvalidDecl();
    return;
  }
}

// OpenCL 1.1 6.5.2: "Variables allocated in the __local address space inside
// a kernel function cannot be initialized."
if (VDecl->getType().getAddressSpace() == LangAS::opencl_local) {
  Diag(VDecl->getLocation(), diag::err_local_cant_init);
  VDecl->setInvalidDecl();
  return;
}

// The LoaderUninitialized attribute acts as a definition (of undef).
if (VDecl->hasAttr<LoaderUninitializedAttr>()) {
  Diag(VDecl->getLocation(), diag::err_loader_uninitialized_cant_init);
  VDecl->setInvalidDecl();
  return;
}

// Get the decls type and save a reference for later, since
// CheckInitializerTypes may change it.
QualType DclT = VDecl->getType(), SavT = DclT;

// Expressions default to 'id' when we're in a debugger
// and we are assigning it to a variable of Objective-C pointer type.
if (getLangOpts().DebuggerCastResultToId && DclT->isObjCObjectPointerType() &&
    Init->getType() == Context.UnknownAnyTy) {
  ExprResult Result = forceUnknownAnyToType(Init, Context.getObjCIdType());
  if (Result.isInvalid()) {
    VDecl->setInvalidDecl();
    return;
  }
  Init = Result.get();
}

// Perform the initialization.
ParenListExpr *CXXDirectInit = dyn_cast<ParenListExpr>(Init);
if (!VDecl->isInvalidDecl()) {
  InitializedEntity Entity = InitializedEntity::InitializeVariable(VDecl);
  InitializationKind Kind = InitializationKind::CreateForInit(
      VDecl->getLocation(), DirectInit, Init);

  MultiExprArg Args = Init;
  if (CXXDirectInit)
    Args = MultiExprArg(CXXDirectInit->getExprs(),
                        CXXDirectInit->getNumExprs());

  // Try to correct any TypoExprs in the initialization arguments.
  for (size_t Idx = 0; Idx < Args.size(); ++Idx) {
    ExprResult Res = CorrectDelayedTyposInExpr(
        Args[Idx], VDecl, /*RecoverUncorrectedTypos=*/true,
        [this, Entity, Kind](Expr *E) {
          InitializationSequence Init(*this, Entity, Kind, MultiExprArg(E));
          return Init.Failed() ? ExprError() : E;
        });
    if (Res.isInvalid()) {
      VDecl->setInvalidDecl();
    } else if (Res.get() != Args[Idx]) {
      Args[Idx] = Res.get();
    }
  }
  if (VDecl->isInvalidDecl())
    return;

  InitializationSequence InitSeq(*this, Entity, Kind, Args,
                                 /*TopLevelOfInitList=*/false,
                                 /*TreatUnavailableAsInvalid=*/false);
  ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Args, &DclT);
  if (Result.isInvalid()) {
    // If the provied initializer fails to initialize the var decl,
    // we attach a recovery expr for better recovery.
    auto RecoveryExpr =
        CreateRecoveryExpr(Init->getBeginLoc(), Init->getEndLoc(), Args);
    if (RecoveryExpr.get())
      VDecl->setInit(RecoveryExpr.get());
    return;
  }

  Init = Result.getAs<Expr>();
}

// Check for self-references within variable initializers.
// Variables declared within a function/method body (except for references)
// are handled by a dataflow analysis.
// This is undefined behavior in C++, but valid in C.
if (getLangOpts().CPlusPlus)
  if (!VDecl->hasLocalStorage() || VDecl->getType()->isRecordType() ||
      VDecl->getType()->isReferenceType())
    CheckSelfReference(*this, RealDecl, Init, DirectInit);

// If the type changed, it means we had an incomplete type that was
// completed by the initializer. For example:
//   int ary[] = { 1, 3, 5 };
// "ary" transitions from an IncompleteArrayType to a ConstantArrayType.
if (!VDecl->isInvalidDecl() && (DclT != SavT))
  VDecl->setType(DclT);

if (!VDecl->isInvalidDecl()) {
  checkUnsafeAssigns(VDecl->getLocation(), VDecl->getType(), Init);

  if (VDecl->hasAttr<BlocksAttr>())
    checkRetainCycles(VDecl, Init);

  // It is safe to assign a weak reference into a strong variable.
  // Although this code can still have problems:
  //   id x = self.weakProp;
  //   id y = self.weakProp;
  // we do not warn to warn spuriously when 'x' and 'y' are on separate
  // paths through the function. This should be revisited if
  // -Wrepeated-use-of-weak is made flow-sensitive.
  if (FunctionScopeInfo *FSI = getCurFunction())
    if ((VDecl->getType().getObjCLifetime() == Qualifiers::OCL_Strong ||
         VDecl->getType().isNonWeakInMRRWithObjCWeak(Context)) &&
        !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak,
                         Init->getBeginLoc()))
      FSI->markSafeWeakUse(Init);
}

// The initialization is usually a full-expression.
//
// FIXME: If this is a braced initialization of an aggregate, it is not
// an expression, and each individual field initializer is a separate
// full-expression. For instance, in:
//
//   struct Temp { ~Temp(); };
//   struct S { S(Temp); };
//   struct T { S a, b; } t = { Temp(), Temp() }
//
// we should destroy the first Temp before constructing the second.
ExprResult Result =
    ActOnFinishFullExpr(Init, VDecl->getLocation(),
                        /*DiscardedValue*/ false, VDecl->isConstexpr());
if (Result.isInvalid()) {
  VDecl->setInvalidDecl();
  return;
}
Init = Result.get();

// Attach the initializer to the decl.
VDecl->setInit(Init);

if (VDecl->isLocalVarDecl()) {
  // Don't check the initializer if the declaration is malformed.
  if (VDecl->isInvalidDecl()) {
    // do nothing

  // OpenCL v1.2 s6.5.3: __constant locals must be constant-initialized.
  // This is true even in C++ for OpenCL.
  } else if (VDecl->getType().getAddressSpace() == LangAS::opencl_constant) {
    CheckForConstantInitializer(Init, DclT);

  // Otherwise, C++ does not restrict the initializer.
  } else if (getLangOpts().CPlusPlus) {
    // do nothing

  // C99 6.7.8p4: All the expressions in an initializer for an object that has
  // static storage duration shall be constant expressions or string literals.
  } else if (VDecl->getStorageClass() == SC_Static) {
    CheckForConstantInitializer(Init, DclT);

  // C89 is stricter than C99 for aggregate initializers.
  // C89 6.5.7p3: All the expressions [...] in an initializer list
  // for an object that has aggregate or union type shall be
  // constant expressions.
  } else if (!getLangOpts().C99 && VDecl->getType()->isAggregateType() &&
             isa<InitListExpr>(Init)) {
    const Expr *Culprit;
    if (!Init->isConstantInitializer(Context, false, &Culprit)) {
      Diag(Culprit->getExprLoc(),
           diag::ext_aggregate_init_not_constant)
        << Culprit->getSourceRange();
    }
  }

  if (auto *E = dyn_cast<ExprWithCleanups>(Init))
    if (auto *BE = dyn_cast<BlockExpr>(E->getSubExpr()->IgnoreParens()))
      if (VDecl->hasLocalStorage())
        BE->getBlockDecl()->setCanAvoidCopyToHeap();
} else if (VDecl->isStaticDataMember() && !VDecl->isInline() &&
           VDecl->getLexicalDeclContext()->isRecord()) {
  // This is an in-class initialization for a static data member, e.g.,
  //
  // struct S {
  //   static const int value = 17;
  // };

  // C++ [class.mem]p4:
  //   A member-declarator can contain a constant-initializer only
  //   if it declares a static member (9.4) of const integral or
  //   const enumeration type, see 9.4.2.
  //
  // C++11 [class.static.data]p3:
  //   If a non-volatile non-inline const static data member is of integral
  //   or enumeration type, its declaration in the class definition can
  //   specify a brace-or-equal-initializer in which every initializer-clause
  //   that is an assignment-expression is a constant expression. A static
  //   data member of literal type can be declared in the class definition
  //   with the constexpr specifier; if so, its declaration shall specify a
  //   brace-or-equal-initializer in which every initializer-clause that is
  //   an assignment-expression is a constant expression.

  // Do nothing on dependent types.
  if (DclT->isDependentType()) {

  // Allow any 'static constexpr' members, whether or not they are of literal
  // type. We separately check that every constexpr variable is of literal
  // type.
  } else if (VDecl->isConstexpr()) {

  // Require constness.
  } else if (!DclT.isConstQualified()) {
    Diag(VDecl->getLocation(), diag::err_in_class_initializer_non_const)
      << Init->getSourceRange();
    VDecl->setInvalidDecl();

  // We allow integer constant expressions in all cases.
  } else if (DclT->isIntegralOrEnumerationType()) {
    // Check whether the expression is a constant expression.
    SourceLocation Loc;
    if (getLangOpts().CPlusPlus11 && DclT.isVolatileQualified())
      // In C++11, a non-constexpr const static data member with an
      // in-class initializer cannot be volatile.
      Diag(VDecl->getLocation(), diag::err_in_class_initializer_volatile);
    else if (Init->isValueDependent())
      ; // Nothing to check.
    else if (Init->isIntegerConstantExpr(Context, &Loc))
      ; // Ok, it's an ICE!
    else if (Init->getType()->isScopedEnumeralType() &&
             Init->isCXX11ConstantExpr(Context))
      ; // Ok, it is a scoped-enum constant expression.
    else if (Init->isEvaluatable(Context)) {
      // If we can constant fold the initializer through heroics, accept it,
      // but report this as a use of an extension for -pedantic.
      Diag(Loc, diag::ext_in_class_initializer_non_constant)
        << Init->getSourceRange();
    } else {
      // Otherwise, this is some crazy unknown case.  Report the issue at the
      // location provided by the isIntegerConstantExpr failed check.
      Diag(Loc, diag::err_in_class_initializer_non_constant)
        << Init->getSourceRange();
      VDecl->setInvalidDecl();
    }

  // We allow foldable floating-point constants as an extension.
  } else if (DclT->isFloatingType()) { // also permits complex, which is ok
    // In C++98, this is a GNU extension. In C++11, it is not, but we support
    // it anyway and provide a fixit to add the 'constexpr'.
    if (getLangOpts().CPlusPlus11) {
      Diag(VDecl->getLocation(),
           diag::ext_in_class_initializer_float_type_cxx11)
          << DclT << Init->getSourceRange();
      Diag(VDecl->getBeginLoc(),
           diag::note_in_class_initializer_float_type_cxx11)
          << FixItHint::CreateInsertion(VDecl->getBeginLoc(), "constexpr ");
    } else {
      Diag(VDecl->getLocation(), diag::ext_in_class_initializer_float_type)
        << DclT << Init->getSourceRange();

      if (!Init->isValueDependent() && !Init->isEvaluatable(Context)) {
        Diag(Init->getExprLoc(), diag::err_in_class_initializer_non_constant)
          << Init->getSourceRange();
        VDecl->setInvalidDecl();
      }
    }

  // Suggest adding 'constexpr' in C++11 for literal types.
  } else if (getLangOpts().CPlusPlus11 && DclT->isLiteralType(Context)) {
    Diag(VDecl->getLocation(), diag::err_in_class_initializer_literal_type)
        << DclT << Init->getSourceRange()
        << FixItHint::CreateInsertion(VDecl->getBeginLoc(), "constexpr ");
    VDecl->setConstexpr(true);

  } else {
    Diag(VDecl->getLocation(), diag::err_in_class_initializer_bad_type)
      << DclT << Init->getSourceRange();
    VDecl->setInvalidDecl();
  }
} else if (VDecl->isFileVarDecl()) {
  // In C, extern is typically used to avoid tentative definitions when
  // declaring variables in headers, but adding an intializer makes it a
  // definition. This is somewhat confusing, so GCC and Clang both warn on it.
  // In C++, extern is often used to give implictly static const variables
  // external linkage, so don't warn in that case. If selectany is present,
  // this might be header code intended for C and C++ inclusion, so apply the
  // C++ rules.
  if (VDecl->getStorageClass() == SC_Extern &&
      ((!getLangOpts().CPlusPlus && !VDecl->hasAttr<SelectAnyAttr>()) ||
       !Context.getBaseElementType(VDecl->getType()).isConstQualified()) &&
      !(getLangOpts().CPlusPlus && VDecl->isExternC()) &&
      !isTemplateInstantiation(VDecl->getTemplateSpecializationKind()))
    Diag(VDecl->getLocation(), diag::warn_extern_init);

  // In Microsoft C++ mode, a const variable defined in namespace scope has
  // external linkage by default if the variable is declared with
  // __declspec(dllexport).
  if (Context.getTargetInfo().getCXXABI().isMicrosoft() &&
      getLangOpts().CPlusPlus && VDecl->getType().isConstQualified() &&
      VDecl->hasAttr<DLLExportAttr>() && VDecl->getDefinition())
    VDecl->setStorageClass(SC_Extern);

  // C99 6.7.8p4. All file scoped initializers need to be constant.
  if (!getLangOpts().CPlusPlus && !VDecl->isInvalidDecl())
    CheckForConstantInitializer(Init, DclT);
}

QualType InitType = Init->getType();
if (!InitType.isNull() &&
    (InitType.hasNonTrivialToPrimitiveDefaultInitializeCUnion() ||
     InitType.hasNonTrivialToPrimitiveCopyCUnion()))
  checkNonTrivialCUnionInInitializer(Init, Init->getExprLoc());

// We will represent direct-initialization similarly to copy-initialization:
//    int x(1);  -as-> int x = 1;
//    ClassType x(a,b,c); -as-> ClassType x = ClassType(a,b,c);
//
// Clients that want to distinguish between the two forms, can check for
// direct initializer using VarDecl::getInitStyle().
// A major benefit is that clients that don't particularly care about which
// exactly form was it (like the CodeGen) can handle both cases without
// special case code.

// C++ 8.5p11:
// The form of initialization (using parentheses or '=') is generally
// insignificant, but does matter when the entity being initialized has a
// class type.
if (CXXDirectInit) {
  assert(DirectInit && "Call-style initializer must be direct init.")((void)0);
  VDecl->setInitStyle(VarDecl::CallInit);
} else if (DirectInit) {
  // This must be list-initialization. No other way is direct-initialization.
  VDecl->setInitStyle(VarDecl::ListInit);
}

if (LangOpts.OpenMP && VDecl->isFileVarDecl())
  DeclsToCheckForDeferredDiags.insert(VDecl);
CheckCompleteVariableDeclaration(VDecl);
12601}

12603/// ActOnInitializerError - Given that there was an error parsing an
12604/// initializer for the given declaration, try to return to some form
12605/// of sanity.
12606void Sema::ActOnInitializerError(Decl *D) {
// Our main concern here is re-establishing invariants like "a
// variable's type is either dependent or complete".
if (!D || D->isInvalidDecl()) return;

VarDecl *VD = dyn_cast<VarDecl>(D);
if (!VD) return;

// Bindings are not usable if we can't make sense of the initializer.
if (auto *DD = dyn_cast<DecompositionDecl>(D))
  for (auto *BD : DD->bindings())
    BD->setInvalidDecl();

// Auto types are meaningless if we can't make sense of the initializer.
if (VD->getType()->isUndeducedType()) {
  D->setInvalidDecl();
  return;
}

QualType Ty = VD->getType();
if (Ty->isDependentType()) return;

// Require a complete type.
if (RequireCompleteType(VD->getLocation(),
                        Context.getBaseElementType(Ty),
                        diag::err_typecheck_decl_incomplete_type)) {
  VD->setInvalidDecl();
  return;
}

// Require a non-abstract type.
if (RequireNonAbstractType(VD->getLocation(), Ty,
                           diag::err_abstract_type_in_decl,
                           AbstractVariableType)) {
  VD->setInvalidDecl();
  return;
}

// Don't bother complaining about constructors or destructors,
// though.
12646}

12648void Sema::ActOnUninitializedDecl(Decl *RealDecl) {
// If there is no declaration, there was an error parsing it. Just ignore it.
if (!RealDecl)
  return;

if (VarDecl *Var = dyn_cast<VarDecl>(RealDecl)) {
  QualType Type = Var->getType();

  // C++1z [dcl.dcl]p1 grammar implies that an initializer is mandatory.
  if (isa<DecompositionDecl>(RealDecl)) {
    Diag(Var->getLocation(), diag::err_decomp_decl_requires_init) << Var;
    Var->setInvalidDecl();
    return;
  }

  if (Type->isUndeducedType() &&
      DeduceVariableDeclarationType(Var, false, nullptr))
    return;

  // C++11 [class.static.data]p3: A static data member can be declared with
  // the constexpr specifier; if so, its declaration shall specify
  // a brace-or-equal-initializer.
  // C++11 [dcl.constexpr]p1: The constexpr specifier shall be applied only to
  // the definition of a variable [...] or the declaration of a static data
  // member.
  if (Var->isConstexpr() && !Var->isThisDeclarationADefinition() &&
      !Var->isThisDeclarationADemotedDefinition()) {
    if (Var->isStaticDataMember()) {
      // C++1z removes the relevant rule; the in-class declaration is always
      // a definition there.
      if (!getLangOpts().CPlusPlus17 &&
          !Context.getTargetInfo().getCXXABI().isMicrosoft()) {
        Diag(Var->getLocation(),
             diag::err_constexpr_static_mem_var_requires_init)
            << Var;
        Var->setInvalidDecl();
        return;
      }
    } else {
      Diag(Var->getLocation(), diag::err_invalid_constexpr_var_decl);
      Var->setInvalidDecl();
      return;
    }
  }

  // OpenCL v1.1 s6.5.3: variables declared in the constant address space must
  // be initialized.
  if (!Var->isInvalidDecl() &&
      Var->getType().getAddressSpace() == LangAS::opencl_constant &&
      Var->getStorageClass() != SC_Extern && !Var->getInit()) {
    bool HasConstExprDefaultConstructor = false;
    if (CXXRecordDecl *RD = Var->getType()->getAsCXXRecordDecl()) {
      for (auto *Ctor : RD->ctors()) {
        if (Ctor->isConstexpr() && Ctor->getNumParams() == 0 &&
            Ctor->getMethodQualifiers().getAddressSpace() ==
                LangAS::opencl_constant) {
          HasConstExprDefaultConstructor = true;
        }
      }
    }
    if (!HasConstExprDefaultConstructor) {
      Diag(Var->getLocation(), diag::err_opencl_constant_no_init);
      Var->setInvalidDecl();
      return;
    }
  }

  if (!Var->isInvalidDecl() && RealDecl->hasAttr<LoaderUninitializedAttr>()) {
    if (Var->getStorageClass() == SC_Extern) {
      Diag(Var->getLocation(), diag::err_loader_uninitialized_extern_decl)
          << Var;
      Var->setInvalidDecl();
      return;
    }
    if (RequireCompleteType(Var->getLocation(), Var->getType(),
                            diag::err_typecheck_decl_incomplete_type)) {
      Var->setInvalidDecl();
      return;
    }
    if (CXXRecordDecl *RD = Var->getType()->getAsCXXRecordDecl()) {
      if (!RD->hasTrivialDefaultConstructor()) {
        Diag(Var->getLocation(), diag::err_loader_uninitialized_trivial_ctor);
        Var->setInvalidDecl();
        return;
      }
    }
    // The declaration is unitialized, no need for further checks.
    return;
  }

  VarDecl::DefinitionKind DefKind = Var->isThisDeclarationADefinition();
  if (!Var->isInvalidDecl() && DefKind != VarDecl::DeclarationOnly &&
      Var->getType().hasNonTrivialToPrimitiveDefaultInitializeCUnion())
    checkNonTrivialCUnion(Var->getType(), Var->getLocation(),
                          NTCUC_DefaultInitializedObject, NTCUK_Init);


  switch (DefKind) {
  case VarDecl::Definition:
    if (!Var->isStaticDataMember() || !Var->getAnyInitializer())
      break;

    // We have an out-of-line definition of a static data member
    // that has an in-class initializer, so we type-check this like
    // a declaration.
    //
    LLVM_FALLTHROUGH[[gnu::fallthrough]];

  case VarDecl::DeclarationOnly:
    // It's only a declaration.

    // Block scope. C99 6.7p7: If an identifier for an object is
    // declared with no linkage (C99 6.2.2p6), the type for the
    // object shall be complete.
    if (!Type->isDependentType() && Var->isLocalVarDecl() &&
        !Var->hasLinkage() && !Var->isInvalidDecl() &&
        RequireCompleteType(Var->getLocation(), Type,
                            diag::err_typecheck_decl_incomplete_type))
      Var->setInvalidDecl();

    // Make sure that the type is not abstract.
    if (!Type->isDependentType() && !Var->isInvalidDecl() &&
        RequireNonAbstractType(Var->getLocation(), Type,
                               diag::err_abstract_type_in_decl,
                               AbstractVariableType))
      Var->setInvalidDecl();
    if (!Type->isDependentType() && !Var->isInvalidDecl() &&
        Var->getStorageClass() == SC_PrivateExtern) {
      Diag(Var->getLocation(), diag::warn_private_extern);
      Diag(Var->getLocation(), diag::note_private_extern);
    }

    if (Context.getTargetInfo().allowDebugInfoForExternalRef() &&
        !Var->isInvalidDecl() && !getLangOpts().CPlusPlus)
      ExternalDeclarations.push_back(Var);

    return;

  case VarDecl::TentativeDefinition:
    // File scope. C99 6.9.2p2: A declaration of an identifier for an
    // object that has file scope without an initializer, and without a
    // storage-class specifier or with the storage-class specifier "static",
    // constitutes a tentative definition. Note: A tentative definition with
    // external linkage is valid (C99 6.2.2p5).
    if (!Var->isInvalidDecl()) {
      if (const IncompleteArrayType *ArrayT
                                  = Context.getAsIncompleteArrayType(Type)) {
        if (RequireCompleteSizedType(
                Var->getLocation(), ArrayT->getElementType(),
                diag::err_array_incomplete_or_sizeless_type))
          Var->setInvalidDecl();
      } else if (Var->getStorageClass() == SC_Static) {
        // C99 6.9.2p3: If the declaration of an identifier for an object is
        // a tentative definition and has internal linkage (C99 6.2.2p3), the
        // declared type shall not be an incomplete type.
        // NOTE: code such as the following
        //     static struct s;
        //     struct s { int a; };
        // is accepted by gcc. Hence here we issue a warning instead of
        // an error and we do not invalidate the static declaration.
        // NOTE: to avoid multiple warnings, only check the first declaration.
        if (Var->isFirstDecl())
          RequireCompleteType(Var->getLocation(), Type,
                              diag::ext_typecheck_decl_incomplete_type);
      }
    }

    // Record the tentative definition; we're done.
    if (!Var->isInvalidDecl())
      TentativeDefinitions.push_back(Var);
    return;
  }

  // Provide a specific diagnostic for uninitialized variable
  // definitions with incomplete array type.
  if (Type->isIncompleteArrayType()) {
    Diag(Var->getLocation(),
         diag::err_typecheck_incomplete_array_needs_initializer);
    Var->setInvalidDecl();
    return;
  }

  // Provide a specific diagnostic for uninitialized variable
  // definitions with reference type.
  if (Type->isReferenceType()) {
    Diag(Var->getLocation(), diag::err_reference_var_requires_init)
        << Var << SourceRange(Var->getLocation(), Var->getLocation());
    Var->setInvalidDecl();
    return;
  }

  // Do not attempt to type-check the default initializer for a
  // variable with dependent type.
  if (Type->isDependentType())
    return;

  if (Var->isInvalidDecl())
    return;

  if (!Var->hasAttr<AliasAttr>()) {
    if (RequireCompleteType(Var->getLocation(),
                            Context.getBaseElementType(Type),
                            diag::err_typecheck_decl_incomplete_type)) {
      Var->setInvalidDecl();
      return;
    }
  } else {
    return;
  }

  // The variable can not have an abstract class type.
  if (RequireNonAbstractType(Var->getLocation(), Type,
                             diag::err_abstract_type_in_decl,
                             AbstractVariableType)) {
    Var->setInvalidDecl();
    return;
  }

  // Check for jumps past the implicit initializer.  C++0x
  // clarifies that this applies to a "variable with automatic
  // storage duration", not a "local variable".
  // C++11 [stmt.dcl]p3
  //   A program that jumps from a point where a variable with automatic
  //   storage duration is not in scope to a point where it is in scope is
  //   ill-formed unless the variable has scalar type, class type with a
  //   trivial default constructor and a trivial destructor, a cv-qualified
  //   version of one of these types, or an array of one of the preceding
  //   types and is declared without an initializer.
  if (getLangOpts().CPlusPlus && Var->hasLocalStorage()) {
    if (const RecordType *Record
          = Context.getBaseElementType(Type)->getAs<RecordType>()) {
      CXXRecordDecl *CXXRecord = cast<CXXRecordDecl>(Record->getDecl());
      // Mark the function (if we're in one) for further checking even if the
      // looser rules of C++11 do not require such checks, so that we can
      // diagnose incompatibilities with C++98.
      if (!CXXRecord->isPOD())
        setFunctionHasBranchProtectedScope();
    }
  }
  // In OpenCL, we can't initialize objects in the __local address space,
  // even implicitly, so don't synthesize an implicit initializer.
  if (getLangOpts().OpenCL &&
      Var->getType().getAddressSpace() == LangAS::opencl_local)
    return;
  // C++03 [dcl.init]p9:
  //   If no initializer is specified for an object, and the
  //   object is of (possibly cv-qualified) non-POD class type (or
  //   array thereof), the object shall be default-initialized; if
  //   the object is of const-qualified type, the underlying class
  //   type shall have a user-declared default
  //   constructor. Otherwise, if no initializer is specified for
  //   a non- static object, the object and its subobjects, if
  //   any, have an indeterminate initial value); if the object
  //   or any of its subobjects are of const-qualified type, the
  //   program is ill-formed.
  // C++0x [dcl.init]p11:
  //   If no initializer is specified for an object, the object is
  //   default-initialized; [...].
  InitializedEntity Entity = InitializedEntity::InitializeVariable(Var);
  InitializationKind Kind
    = InitializationKind::CreateDefault(Var->getLocation());

  InitializationSequence InitSeq(*this, Entity, Kind, None);
  ExprResult Init = InitSeq.Perform(*this, Entity, Kind, None);

  if (Init.get()) {
    Var->setInit(MaybeCreateExprWithCleanups(Init.get()));
    // This is important for template substitution.
    Var->setInitStyle(VarDecl::CallInit);
  } else if (Init.isInvalid()) {
    // If default-init fails, attach a recovery-expr initializer to track
    // that initialization was attempted and failed.
    auto RecoveryExpr =
        CreateRecoveryExpr(Var->getLocation(), Var->getLocation(), {});
    if (RecoveryExpr.get())
      Var->setInit(RecoveryExpr.get());
  }

  CheckCompleteVariableDeclaration(Var);
}
12928}

12930void Sema::ActOnCXXForRangeDecl(Decl *D) {
// If there is no declaration, there was an error parsing it. Ignore it.
if (!D)
  return;

VarDecl *VD = dyn_cast<VarDecl>(D);
if (!VD) {
  Diag(D->getLocation(), diag::err_for_range_decl_must_be_var);
  D->setInvalidDecl();
  return;
}

VD->setCXXForRangeDecl(true);

// for-range-declaration cannot be given a storage class specifier.
int Error = -1;
switch (VD->getStorageClass()) {
case SC_None:
  break;
case SC_Extern:
  Error = 0;
  break;
case SC_Static:
  Error = 1;
  break;
case SC_PrivateExtern:
  Error = 2;
  break;
case SC_Auto:
  Error = 3;
  break;
case SC_Register:
  Error = 4;
  break;
}

// for-range-declaration cannot be given a storage class specifier con't.
switch (VD->getTSCSpec()) {
case TSCS_thread_local:
  Error = 6;
  break;
case TSCS___thread:
case TSCS__Thread_local:
case TSCS_unspecified:
  break;
}

if (Error != -1) {
  Diag(VD->getOuterLocStart(), diag::err_for_range_storage_class)
      << VD << Error;
  D->setInvalidDecl();
}
12982}

12984StmtResult
12985Sema::ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
                               IdentifierInfo *Ident,
                               ParsedAttributes &Attrs,
                               SourceLocation AttrEnd) {
// C++1y [stmt.iter]p1:
//   A range-based for statement of the form
//      for ( for-range-identifier : for-range-initializer ) statement
//   is equivalent to
//      for ( auto&& for-range-identifier : for-range-initializer ) statement
DeclSpec DS(Attrs.getPool().getFactory());

const char *PrevSpec;
unsigned DiagID;
DS.SetTypeSpecType(DeclSpec::TST_auto, IdentLoc, PrevSpec, DiagID,
                   getPrintingPolicy());

Declarator D(DS, DeclaratorContext::ForInit);
D.SetIdentifier(Ident, IdentLoc);
D.takeAttributes(Attrs, AttrEnd);

D.AddTypeInfo(DeclaratorChunk::getReference(0, IdentLoc, /*lvalue*/ false),
              IdentLoc);
Decl *Var = ActOnDeclarator(S, D);
cast<VarDecl>(Var)->setCXXForRangeDecl(true);
FinalizeDeclaration(Var);
return ActOnDeclStmt(FinalizeDeclaratorGroup(S, DS, Var), IdentLoc,
                     AttrEnd.isValid() ? AttrEnd : IdentLoc);
13012}

13014void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
if (var->isInvalidDecl()) return;

MaybeAddCUDAConstantAttr(var);

if (getLangOpts().OpenCL) {
  // OpenCL v2.0 s6.12.5 - Every block variable declaration must have an
  // initialiser
  if (var->getTypeSourceInfo()->getType()->isBlockPointerType() &&
      !var->hasInit()) {
    Diag(var->getLocation(), diag::err_opencl_invalid_block_declaration)
        << 1 /*Init*/;
    var->setInvalidDecl();
    return;
  }
}

// In Objective-C, don't allow jumps past the implicit initialization of a
// local retaining variable.
if (getLangOpts().ObjC &&
    var->hasLocalStorage()) {
  switch (var->getType().getObjCLifetime()) {
  case Qualifiers::OCL_None:
  case Qualifiers::OCL_ExplicitNone:
  case Qualifiers::OCL_Autoreleasing:
    break;

  case Qualifiers::OCL_Weak:
  case Qualifiers::OCL_Strong:
    setFunctionHasBranchProtectedScope();
    break;
  }
}

if (var->hasLocalStorage() &&
    var->getType().isDestructedType() == QualType::DK_nontrivial_c_struct)
  setFunctionHasBranchProtectedScope();

// Warn about externally-visible variables being defined without a
// prior declaration.  We only want to do this for global
// declarations, but we also specifically need to avoid doing it for
// class members because the linkage of an anonymous class can
// change if it's later given a typedef name.
if (var->isThisDeclarationADefinition() &&
    var->getDeclContext()->getRedeclContext()->isFileContext() &&
    var->isExternallyVisible() && var->hasLinkage() &&
    !var->isInline() && !var->getDescribedVarTemplate() &&
    !isa<VarTemplatePartialSpecializationDecl>(var) &&
    !isTemplateInstantiation(var->getTemplateSpecializationKind()) &&
    !getDiagnostics().isIgnored(diag::warn_missing_variable_declarations,
                                var->getLocation())) {
  // Find a previous declaration that's not a definition.
  VarDecl *prev = var->getPreviousDecl();
  while (prev && prev->isThisDeclarationADefinition())
    prev = prev->getPreviousDecl();

  if (!prev) {
    Diag(var->getLocation(), diag::warn_missing_variable_declarations) << var;
    Diag(var->getTypeSpecStartLoc(), diag::note_static_for_internal_linkage)
        << /* variable */ 0;
  }
}

// Cache the result of checking for constant initialization.
Optional<bool> CacheHasConstInit;
const Expr *CacheCulprit = nullptr;
auto checkConstInit = [&]() mutable {
  if (!CacheHasConstInit)
    CacheHasConstInit = var->getInit()->isConstantInitializer(
          Context, var->getType()->isReferenceType(), &CacheCulprit);
  return *CacheHasConstInit;
};

if (var->getTLSKind() == VarDecl::TLS_Static) {
  if (var->getType().isDestructedType()) {
    // GNU C++98 edits for __thread, [basic.start.term]p3:
    //   The type of an object with thread storage duration shall not
    //   have a non-trivial destructor.
    Diag(var->getLocation(), diag::err_thread_nontrivial_dtor);
    if (getLangOpts().CPlusPlus11)
      Diag(var->getLocation(), diag::note_use_thread_local);
  } else if (getLangOpts().CPlusPlus && var->hasInit()) {
    if (!checkConstInit()) {
      // GNU C++98 edits for __thread, [basic.start.init]p4:
      //   An object of thread storage duration shall not require dynamic
      //   initialization.
      // FIXME: Need strict checking here.
      Diag(CacheCulprit->getExprLoc(), diag::err_thread_dynamic_init)
        << CacheCulprit->getSourceRange();
      if (getLangOpts().CPlusPlus11)
        Diag(var->getLocation(), diag::note_use_thread_local);
    }
  }
}


if (!var->getType()->isStructureType() && var->hasInit() &&
    isa<InitListExpr>(var->getInit())) {
  const auto *ILE = cast<InitListExpr>(var->getInit());
  unsigned NumInits = ILE->getNumInits();
  if (NumInits > 2)
    for (unsigned I = 0; I < NumInits; ++I) {
      const auto *Init = ILE->getInit(I);
      if (!Init)
        break;
      const auto *SL = dyn_cast<StringLiteral>(Init->IgnoreImpCasts());
      if (!SL)
        break;

      unsigned NumConcat = SL->getNumConcatenated();
      // Diagnose missing comma in string array initialization.
      // Do not warn when all the elements in the initializer are concatenated
      // together. Do not warn for macros too.
      if (NumConcat == 2 && !SL->getBeginLoc().isMacroID()) {
        bool OnlyOneMissingComma = true;
        for (unsigned J = I + 1; J < NumInits; ++J) {
          const auto *Init = ILE->getInit(J);
          if (!Init)
            break;
          const auto *SLJ = dyn_cast<StringLiteral>(Init->IgnoreImpCasts());
          if (!SLJ || SLJ->getNumConcatenated() > 1) {
            OnlyOneMissingComma = false;
            break;
          }
        }

        if (OnlyOneMissingComma) {
          SmallVector<FixItHint, 1> Hints;
          for (unsigned i = 0; i < NumConcat - 1; ++i)
            Hints.push_back(FixItHint::CreateInsertion(
                PP.getLocForEndOfToken(SL->getStrTokenLoc(i)), ","));

          Diag(SL->getStrTokenLoc(1),
               diag::warn_concatenated_literal_array_init)
              << Hints;
          Diag(SL->getBeginLoc(),
               diag::note_concatenated_string_literal_silence);
        }
        // In any case, stop now.
        break;
      }
    }
}


QualType type = var->getType();

if (var->hasAttr<BlocksAttr>())
  getCurFunction()->addByrefBlockVar(var);

Expr *Init = var->getInit();
bool GlobalStorage = var->hasGlobalStorage();
bool IsGlobal = GlobalStorage && !var->isStaticLocal();
QualType baseType = Context.getBaseElementType(type);
bool HasConstInit = true;

// Check whether the initializer is sufficiently constant.
if (getLangOpts().CPlusPlus && !type->isDependentType() && Init &&
    !Init->isValueDependent() &&
    (GlobalStorage || var->isConstexpr() ||
     var->mightBeUsableInConstantExpressions(Context))) {
  // If this variable might have a constant initializer or might be usable in
  // constant expressions, check whether or not it actually is now.  We can't
  // do this lazily, because the result might depend on things that change
  // later, such as which constexpr functions happen to be defined.
  SmallVector<PartialDiagnosticAt, 8> Notes;
  if (!getLangOpts().CPlusPlus11) {
    // Prior to C++11, in contexts where a constant initializer is required,
    // the set of valid constant initializers is described by syntactic rules
    // in [expr.const]p2-6.
    // FIXME: Stricter checking for these rules would be useful for constinit /
    // -Wglobal-constructors.
    HasConstInit = checkConstInit();

    // Compute and cache the constant value, and remember that we have a
    // constant initializer.
    if (HasConstInit) {
      (void)var->checkForConstantInitialization(Notes);
      Notes.clear();
    } else if (CacheCulprit) {
      Notes.emplace_back(CacheCulprit->getExprLoc(),
                         PDiag(diag::note_invalid_subexpr_in_const_expr));
      Notes.back().second << CacheCulprit->getSourceRange();
    }
  } else {
    // Evaluate the initializer to see if it's a constant initializer.
    HasConstInit = var->checkForConstantInitialization(Notes);
  }

  if (HasConstInit) {
    // FIXME: Consider replacing the initializer with a ConstantExpr.
  } else if (var->isConstexpr()) {
    SourceLocation DiagLoc = var->getLocation();
    // If the note doesn't add any useful information other than a source
    // location, fold it into the primary diagnostic.
    if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
                                 diag::note_invalid_subexpr_in_const_expr) {
      DiagLoc = Notes[0].first;
      Notes.clear();
    }
    Diag(DiagLoc, diag::err_constexpr_var_requires_const_init)
        << var << Init->getSourceRange();
    for (unsigned I = 0, N = Notes.size(); I != N; ++I)
      Diag(Notes[I].first, Notes[I].second);
  } else if (GlobalStorage && var->hasAttr<ConstInitAttr>()) {
    auto *Attr = var->getAttr<ConstInitAttr>();
    Diag(var->getLocation(), diag::err_require_constant_init_failed)
        << Init->getSourceRange();
    Diag(Attr->getLocation(), diag::note_declared_required_constant_init_here)
        << Attr->getRange() << Attr->isConstinit();
    for (auto &it : Notes)
      Diag(it.first, it.second);
  } else if (IsGlobal &&
             !getDiagnostics().isIgnored(diag::warn_global_constructor,
                                         var->getLocation())) {
    // Warn about globals which don't have a constant initializer.  Don't
    // warn about globals with a non-trivial destructor because we already
    // warned about them.
    CXXRecordDecl *RD = baseType->getAsCXXRecordDecl();
    if (!(RD && !RD->hasTrivialDestructor())) {
      // checkConstInit() here permits trivial default initialization even in
      // C++11 onwards, where such an initializer is not a constant initializer
      // but nonetheless doesn't require a global constructor.
      if (!checkConstInit())
        Diag(var->getLocation(), diag::warn_global_constructor)
            << Init->getSourceRange();
    }
  }
}

// Apply section attributes and pragmas to global variables.
if (GlobalStorage && var->isThisDeclarationADefinition() &&
    !inTemplateInstantiation()) {
  PragmaStack<StringLiteral *> *Stack = nullptr;
  int SectionFlags = ASTContext::PSF_Read;
  if (var->getType().isConstQualified()) {
    if (HasConstInit)
      Stack = &ConstSegStack;
    else {
      Stack = &BSSSegStack;
      SectionFlags |= ASTContext::PSF_Write;
    }
  } else if (var->hasInit() && HasConstInit) {
    Stack = &DataSegStack;
    SectionFlags |= ASTContext::PSF_Write;
  } else {
    Stack = &BSSSegStack;
    SectionFlags |= ASTContext::PSF_Write;
  }
  if (const SectionAttr *SA = var->getAttr<SectionAttr>()) {
    if (SA->getSyntax() == AttributeCommonInfo::AS_Declspec)
      SectionFlags |= ASTContext::PSF_Implicit;
    UnifySection(SA->getName(), SectionFlags, var);
  } else if (Stack->CurrentValue) {
    SectionFlags |= ASTContext::PSF_Implicit;
    auto SectionName = Stack->CurrentValue->getString();
    var->addAttr(SectionAttr::CreateImplicit(
        Context, SectionName, Stack->CurrentPragmaLocation,
        AttributeCommonInfo::AS_Pragma, SectionAttr::Declspec_allocate));
    if (UnifySection(SectionName, SectionFlags, var))
      var->dropAttr<SectionAttr>();
  }

  // Apply the init_seg attribute if this has an initializer.  If the
  // initializer turns out to not be dynamic, we'll end up ignoring this
  // attribute.
  if (CurInitSeg && var->getInit())
    var->addAttr(InitSegAttr::CreateImplicit(Context, CurInitSeg->getString(),
                                             CurInitSegLoc,
                                             AttributeCommonInfo::AS_Pragma));
}

// All the following checks are C++ only.
if (!getLangOpts().CPlusPlus) {
  // If this variable must be emitted, add it as an initializer for the
  // current module.
  if (Context.DeclMustBeEmitted(var) && !ModuleScopes.empty())
    Context.addModuleInitializer(ModuleScopes.back().Module, var);
  return;
}

// Require the destructor.
if (!type->isDependentType())
  if (const RecordType *recordType = baseType->getAs<RecordType>())
    FinalizeVarWithDestructor(var, recordType);

// If this variable must be emitted, add it as an initializer for the current
// module.
if (Context.DeclMustBeEmitted(var) && !ModuleScopes.empty())
  Context.addModuleInitializer(ModuleScopes.back().Module, var);

// Build the bindings if this is a structured binding declaration.
if (auto *DD = dyn_cast<DecompositionDecl>(var))
  CheckCompleteDecompositionDeclaration(DD);
13308}

13310/// Check if VD needs to be dllexport/dllimport due to being in a
13311/// dllexport/import function.
13312void Sema::CheckStaticLocalForDllExport(VarDecl *VD) {
assert(VD->isStaticLocal())((void)0);

auto *FD = dyn_cast_or_null<FunctionDecl>(VD->getParentFunctionOrMethod());

// Find outermost function when VD is in lambda function.
while (FD && !getDLLAttr(FD) &&
       !FD->hasAttr<DLLExportStaticLocalAttr>() &&
       !FD->hasAttr<DLLImportStaticLocalAttr>()) {
  FD = dyn_cast_or_null<FunctionDecl>(FD->getParentFunctionOrMethod());
}

if (!FD)
  return;

// Static locals inherit dll attributes from their function.
if (Attr *A = getDLLAttr(FD)) {
  auto *NewAttr = cast<InheritableAttr>(A->clone(getASTContext()));
  NewAttr->setInherited(true);
  VD->addAttr(NewAttr);
} else if (Attr *A = FD->getAttr<DLLExportStaticLocalAttr>()) {
  auto *NewAttr = DLLExportAttr::CreateImplicit(getASTContext(), *A);
  NewAttr->setInherited(true);
  VD->addAttr(NewAttr);

  // Export this function to enforce exporting this static variable even
  // if it is not used in this compilation unit.
  if (!FD->hasAttr<DLLExportAttr>())
    FD->addAttr(NewAttr);

} else if (Attr *A = FD->getAttr<DLLImportStaticLocalAttr>()) {
  auto *NewAttr = DLLImportAttr::CreateImplicit(getASTContext(), *A);
  NewAttr->setInherited(true);
  VD->addAttr(NewAttr);
}
13347}

13349/// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform
13350/// any semantic actions necessary after any initializer has been attached.
13351void Sema::FinalizeDeclaration(Decl *ThisDecl) {
// Note that we are no longer parsing the initializer for this declaration.
ParsingInitForAutoVars.erase(ThisDecl);

VarDecl *VD = dyn_cast_or_null<VarDecl>(ThisDecl);
if (!VD)
  return;

// Apply an implicit SectionAttr if '#pragma clang section bss|data|rodata' is active
if (VD->hasGlobalStorage() && VD->isThisDeclarationADefinition() &&
    !inTemplateInstantiation() && !VD->hasAttr<SectionAttr>()) {
  if (PragmaClangBSSSection.Valid)
    VD->addAttr(PragmaClangBSSSectionAttr::CreateImplicit(
        Context, PragmaClangBSSSection.SectionName,
        PragmaClangBSSSection.PragmaLocation,
        AttributeCommonInfo::AS_Pragma));
  if (PragmaClangDataSection.Valid)
    VD->addAttr(PragmaClangDataSectionAttr::CreateImplicit(
        Context, PragmaClangDataSection.SectionName,
        PragmaClangDataSection.PragmaLocation,
        AttributeCommonInfo::AS_Pragma));
  if (PragmaClangRodataSection.Valid)
    VD->addAttr(PragmaClangRodataSectionAttr::CreateImplicit(
        Context, PragmaClangRodataSection.SectionName,
        PragmaClangRodataSection.PragmaLocation,
        AttributeCommonInfo::AS_Pragma));
  if (PragmaClangRelroSection.Valid)
    VD->addAttr(PragmaClangRelroSectionAttr::CreateImplicit(
        Context, PragmaClangRelroSection.SectionName,
        PragmaClangRelroSection.PragmaLocation,
        AttributeCommonInfo::AS_Pragma));
}

if (auto *DD = dyn_cast<DecompositionDecl>(ThisDecl)) {
  for (auto *BD : DD->bindings()) {
    FinalizeDeclaration(BD);
  }
}

checkAttributesAfterMerging(*this, *VD);

// Perform TLS alignment check here after attributes attached to the variable
// which may affect the alignment have been processed. Only perform the check
// if the target has a maximum TLS alignment (zero means no constraints).
if (unsigned MaxAlign = Context.getTargetInfo().getMaxTLSAlign()) {
  // Protect the check so that it's not performed on dependent types and
  // dependent alignments (we can't determine the alignment in that case).
  if (VD->getTLSKind() && !VD->hasDependentAlignment()) {
    CharUnits MaxAlignChars = Context.toCharUnitsFromBits(MaxAlign);
    if (Context.getDeclAlign(VD) > MaxAlignChars) {
      Diag(VD->getLocation(), diag::err_tls_var_aligned_over_maximum)
        << (unsigned)Context.getDeclAlign(VD).getQuantity() << VD
        << (unsigned)MaxAlignChars.getQuantity();
    }
  }
}

if (VD->isStaticLocal())
  CheckStaticLocalForDllExport(VD);

// Perform check for initializers of device-side global variables.
// CUDA allows empty constructors as initializers (see E.2.3.1, CUDA
// 7.5). We must also apply the same checks to all __shared__
// variables whether they are local or not. CUDA also allows
// constant initializers for __constant__ and __device__ variables.
if (getLangOpts().CUDA)
  checkAllowedCUDAInitializer(VD);

// Grab the dllimport or dllexport attribute off of the VarDecl.
const InheritableAttr *DLLAttr = getDLLAttr(VD);

// Imported static data members cannot be defined out-of-line.
if (const auto *IA = dyn_cast_or_null<DLLImportAttr>(DLLAttr)) {
  if (VD->isStaticDataMember() && VD->isOutOfLine() &&
      VD->isThisDeclarationADefinition()) {
    // We allow definitions of dllimport class template static data members
    // with a warning.
    CXXRecordDecl *Context =
      cast<CXXRecordDecl>(VD->getFirstDecl()->getDeclContext());
    bool IsClassTemplateMember =
        isa<ClassTemplatePartialSpecializationDecl>(Context) ||
        Context->getDescribedClassTemplate();

    Diag(VD->getLocation(),
         IsClassTemplateMember
             ? diag::warn_attribute_dllimport_static_field_definition
             : diag::err_attribute_dllimport_static_field_definition);
    Diag(IA->getLocation(), diag::note_attribute);
    if (!IsClassTemplateMember)
      VD->setInvalidDecl();
  }
}

// dllimport/dllexport variables cannot be thread local, their TLS index
// isn't exported with the variable.
if (DLLAttr && VD->getTLSKind()) {
  auto *F = dyn_cast_or_null<FunctionDecl>(VD->getParentFunctionOrMethod());
  if (F && getDLLAttr(F)) {
    assert(VD->isStaticLocal())((void)0);
    // But if this is a static local in a dlimport/dllexport function, the
    // function will never be inlined, which means the var would never be
    // imported, so having it marked import/export is safe.
  } else {
    Diag(VD->getLocation(), diag::err_attribute_dll_thread_local) << VD
                                                                  << DLLAttr;
    VD->setInvalidDecl();
  }
}

if (UsedAttr *Attr = VD->getAttr<UsedAttr>()) {
  if (!Attr->isInherited() && !VD->isThisDeclarationADefinition()) {
    Diag(Attr->getLocation(), diag::warn_attribute_ignored_on_non_definition)
        << Attr;
    VD->dropAttr<UsedAttr>();
  }
}
if (RetainAttr *Attr = VD->getAttr<RetainAttr>()) {
  if (!Attr->isInherited() && !VD->isThisDeclarationADefinition()) {
    Diag(Attr->getLocation(), diag::warn_attribute_ignored_on_non_definition)
        << Attr;
    VD->dropAttr<RetainAttr>();
  }
}

const DeclContext *DC = VD->getDeclContext();
// If there's a #pragma GCC visibility in scope, and this isn't a class
// member, set the visibility of this variable.
if (DC->getRedeclContext()->isFileContext() && VD->isExternallyVisible())
  AddPushedVisibilityAttribute(VD);

// FIXME: Warn on unused var template partial specializations.
if (VD->isFileVarDecl() && !isa<VarTemplatePartialSpecializationDecl>(VD))
  MarkUnusedFileScopedDecl(VD);

// Now we have parsed the initializer and can update the table of magic
// tag values.
if (!VD->hasAttr<TypeTagForDatatypeAttr>() ||
    !VD->getType()->isIntegralOrEnumerationType())
  return;

for (const auto *I : ThisDecl->specific_attrs<TypeTagForDatatypeAttr>()) {
  const Expr *MagicValueExpr = VD->getInit();
  if (!MagicValueExpr) {
    continue;
  }
  Optional<llvm::APSInt> MagicValueInt;
  if (!(MagicValueInt = MagicValueExpr->getIntegerConstantExpr(Context))) {
    Diag(I->getRange().getBegin(),
         diag::err_type_tag_for_datatype_not_ice)
      << LangOpts.CPlusPlus << MagicValueExpr->getSourceRange();
    continue;
  }
  if (MagicValueInt->getActiveBits() > 64) {
    Diag(I->getRange().getBegin(),
         diag::err_type_tag_for_datatype_too_large)
      << LangOpts.CPlusPlus << MagicValueExpr->getSourceRange();
    continue;
  }
  uint64_t MagicValue = MagicValueInt->getZExtValue();
  RegisterTypeTagForDatatype(I->getArgumentKind(),
                             MagicValue,
                             I->getMatchingCType(),
                             I->getLayoutCompatible(),
                             I->getMustBeNull());
}
13516}

13518static bool hasDeducedAuto(DeclaratorDecl *DD) {
auto *VD = dyn_cast<VarDecl>(DD);
return VD && !VD->getType()->hasAutoForTrailingReturnType();
13521}

13523Sema::DeclGroupPtrTy Sema::FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
                                                 ArrayRef<Decl *> Group) {
SmallVector<Decl*, 8> Decls;

if (DS.isTypeSpecOwned())
  Decls.push_back(DS.getRepAsDecl());

DeclaratorDecl *FirstDeclaratorInGroup = nullptr;
DecompositionDecl *FirstDecompDeclaratorInGroup = nullptr;
bool DiagnosedMultipleDecomps = false;
DeclaratorDecl *FirstNonDeducedAutoInGroup = nullptr;
bool DiagnosedNonDeducedAuto = false;

for (unsigned i = 0, e = Group.size(); i != e; ++i) {
  if (Decl *D = Group[i]) {
    // For declarators, there are some additional syntactic-ish checks we need
    // to perform.
    if (auto *DD = dyn_cast<DeclaratorDecl>(D)) {
      if (!FirstDeclaratorInGroup)
        FirstDeclaratorInGroup = DD;
      if (!FirstDecompDeclaratorInGroup)
        FirstDecompDeclaratorInGroup = dyn_cast<DecompositionDecl>(D);
      if (!FirstNonDeducedAutoInGroup && DS.hasAutoTypeSpec() &&
          !hasDeducedAuto(DD))
        FirstNonDeducedAutoInGroup = DD;

      if (FirstDeclaratorInGroup != DD) {
        // A decomposition declaration cannot be combined with any other
        // declaration in the same group.
        if (FirstDecompDeclaratorInGroup && !DiagnosedMultipleDecomps) {
          Diag(FirstDecompDeclaratorInGroup->getLocation(),
               diag::err_decomp_decl_not_alone)
              << FirstDeclaratorInGroup->getSourceRange()
              << DD->getSourceRange();
          DiagnosedMultipleDecomps = true;
        }

        // A declarator that uses 'auto' in any way other than to declare a
        // variable with a deduced type cannot be combined with any other
        // declarator in the same group.
        if (FirstNonDeducedAutoInGroup && !DiagnosedNonDeducedAuto) {
          Diag(FirstNonDeducedAutoInGroup->getLocation(),
               diag::err_auto_non_deduced_not_alone)
              << FirstNonDeducedAutoInGroup->getType()
                     ->hasAutoForTrailingReturnType()
              << FirstDeclaratorInGroup->getSourceRange()
              << DD->getSourceRange();
          DiagnosedNonDeducedAuto = true;
        }
      }
    }

    Decls.push_back(D);
  }
}

if (DeclSpec::isDeclRep(DS.getTypeSpecType())) {
  if (TagDecl *Tag = dyn_cast_or_null<TagDecl>(DS.getRepAsDecl())) {
    handleTagNumbering(Tag, S);
    if (FirstDeclaratorInGroup && !Tag->hasNameForLinkage() &&
        getLangOpts().CPlusPlus)
      Context.addDeclaratorForUnnamedTagDecl(Tag, FirstDeclaratorInGroup);
  }
}

return BuildDeclaratorGroup(Decls);
13589}

13591/// BuildDeclaratorGroup - convert a list of declarations into a declaration
13592/// group, performing any necessary semantic checking.
13593Sema::DeclGroupPtrTy
13594Sema::BuildDeclaratorGroup(MutableArrayRef<Decl *> Group) {
// C++14 [dcl.spec.auto]p7: (DR1347)
//   If the type that replaces the placeholder type is not the same in each
//   deduction, the program is ill-formed.
if (Group.size() > 1) {
  QualType Deduced;
  VarDecl *DeducedDecl = nullptr;
  for (unsigned i = 0, e = Group.size(); i != e; ++i) {
    VarDecl *D = dyn_cast<VarDecl>(Group[i]);
    if (!D || D->isInvalidDecl())
      break;
    DeducedType *DT = D->getType()->getContainedDeducedType();
    if (!DT || DT->getDeducedType().isNull())
      continue;
    if (Deduced.isNull()) {
      Deduced = DT->getDeducedType();
      DeducedDecl = D;
    } else if (!Context.hasSameType(DT->getDeducedType(), Deduced)) {
      auto *AT = dyn_cast<AutoType>(DT);
      auto Dia = Diag(D->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
                      diag::err_auto_different_deductions)
                 << (AT ? (unsigned)AT->getKeyword() : 3) << Deduced
                 << DeducedDecl->getDeclName() << DT->getDeducedType()
                 << D->getDeclName();
      if (DeducedDecl->hasInit())
        Dia << DeducedDecl->getInit()->getSourceRange();
      if (D->getInit())
        Dia << D->getInit()->getSourceRange();
      D->setInvalidDecl();
      break;
    }
  }
}

ActOnDocumentableDecls(Group);

return DeclGroupPtrTy::make(
    DeclGroupRef::Create(Context, Group.data(), Group.size()));
13632}

13634void Sema::ActOnDocumentableDecl(Decl *D) {
ActOnDocumentableDecls(D);
13636}

13638void Sema::ActOnDocumentableDecls(ArrayRef<Decl *> Group) {
// Don't parse the comment if Doxygen diagnostics are ignored.
if (Group.empty() || !Group[0])
  return;

if (Diags.isIgnored(diag::warn_doc_param_not_found,
                    Group[0]->getLocation()) &&
    Diags.isIgnored(diag::warn_unknown_comment_command_name,
                    Group[0]->getLocation()))
  return;

if (Group.size() >= 2) {
  // This is a decl group.  Normally it will contain only declarations
  // produced from declarator list.  But in case we have any definitions or
  // additional declaration references:
  //   'typedef struct S {} S;'
  //   'typedef struct S *S;'
  //   'struct S *pS;'
  // FinalizeDeclaratorGroup adds these as separate declarations.
  Decl *MaybeTagDecl = Group[0];
  if (MaybeTagDecl && isa<TagDecl>(MaybeTagDecl)) {
    Group = Group.slice(1);
  }
}

// FIMXE: We assume every Decl in the group is in the same file.
// This is false when preprocessor constructs the group from decls in
// different files (e. g. macros or #include).
Context.attachCommentsToJustParsedDecls(Group, &getPreprocessor());
13667}

13669/// Common checks for a parameter-declaration that should apply to both function
13670/// parameters and non-type template parameters.
13671void Sema::CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D) {
// Check that there are no default arguments inside the type of this
// parameter.
if (getLangOpts().CPlusPlus)
  CheckExtraCXXDefaultArguments(D);

// Parameter declarators cannot be qualified (C++ [dcl.meaning]p1).
if (D.getCXXScopeSpec().isSet()) {
  Diag(D.getIdentifierLoc(), diag::err_qualified_param_declarator)
    << D.getCXXScopeSpec().getRange();
}

// [dcl.meaning]p1: An unqualified-id occurring in a declarator-id shall be a
// simple identifier except [...irrelevant cases...].
switch (D.getName().getKind()) {
case UnqualifiedIdKind::IK_Identifier:
  break;

case UnqualifiedIdKind::IK_OperatorFunctionId:
case UnqualifiedIdKind::IK_ConversionFunctionId:
case UnqualifiedIdKind::IK_LiteralOperatorId:
case UnqualifiedIdKind::IK_ConstructorName:
case UnqualifiedIdKind::IK_DestructorName:
case UnqualifiedIdKind::IK_ImplicitSelfParam:
case UnqualifiedIdKind::IK_DeductionGuideName:
  Diag(D.getIdentifierLoc(), diag::err_bad_parameter_name)
    << GetNameForDeclarator(D).getName();
  break;

case UnqualifiedIdKind::IK_TemplateId:
case UnqualifiedIdKind::IK_ConstructorTemplateId:
  // GetNameForDeclarator would not produce a useful name in this case.
  Diag(D.getIdentifierLoc(), diag::err_bad_parameter_name_template_id);
  break;
}
13706}

13708/// ActOnParamDeclarator - Called from Parser::ParseFunctionDeclarator()
13709/// to introduce parameters into function prototype scope.
13710Decl *Sema::ActOnParamDeclarator(Scope *S, Declarator &D) {
const DeclSpec &DS = D.getDeclSpec();

// Verify C99 6.7.5.3p2: The only SCS allowed is 'register'.

// C++03 [dcl.stc]p2 also permits 'auto'.
StorageClass SC = SC_None;
if (DS.getStorageClassSpec() == DeclSpec::SCS_register) {
  SC = SC_Register;
  // In C++11, the 'register' storage class specifier is deprecated.
  // In C++17, it is not allowed, but we tolerate it as an extension.
  if (getLangOpts().CPlusPlus11) {
    Diag(DS.getStorageClassSpecLoc(),
         getLangOpts().CPlusPlus17 ? diag::ext_register_storage_class
                                   : diag::warn_deprecated_register)
      << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
  }
} else if (getLangOpts().CPlusPlus &&
           DS.getStorageClassSpec() == DeclSpec::SCS_auto) {
  SC = SC_Auto;
} else if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified) {
  Diag(DS.getStorageClassSpecLoc(),
       diag::err_invalid_storage_class_in_func_decl);
  D.getMutableDeclSpec().ClearStorageClassSpecs();
}

if (DeclSpec::TSCS TSCS = DS.getThreadStorageClassSpec())
  Diag(DS.getThreadStorageClassSpecLoc(), diag::err_invalid_thread)
    << DeclSpec::getSpecifierName(TSCS);
if (DS.isInlineSpecified())
  Diag(DS.getInlineSpecLoc(), diag::err_inline_non_function)
      << getLangOpts().CPlusPlus17;
if (DS.hasConstexprSpecifier())
  Diag(DS.getConstexprSpecLoc(), diag::err_invalid_constexpr)
      << 0 << static_cast<int>(D.getDeclSpec().getConstexprSpecifier());

DiagnoseFunctionSpecifiers(DS);

CheckFunctionOrTemplateParamDeclarator(S, D);

TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
QualType parmDeclType = TInfo->getType();

// Check for redeclaration of parameters, e.g. int foo(int x, int x);
IdentifierInfo *II = D.getIdentifier();
if (II) {
  LookupResult R(*this, II, D.getIdentifierLoc(), LookupOrdinaryName,
                 ForVisibleRedeclaration);
  LookupName(R, S);
  if (R.isSingleResult()) {
    NamedDecl *PrevDecl = R.getFoundDecl();
    if (PrevDecl->isTemplateParameter()) {
      // Maybe we will complain about the shadowed template parameter.
      DiagnoseTemplateParameterShadow(D.getIdentifierLoc(), PrevDecl);
      // Just pretend that we didn't see the previous declaration.
      PrevDecl = nullptr;
    } else if (S->isDeclScope(PrevDecl)) {
      Diag(D.getIdentifierLoc(), diag::err_param_redefinition) << II;
      Diag(PrevDecl->getLocation(), diag::note_previous_declaration);

      // Recover by removing the name
      II = nullptr;
      D.SetIdentifier(nullptr, D.getIdentifierLoc());
      D.setInvalidType(true);
    }
  }
}

// Temporarily put parameter variables in the translation unit, not
// the enclosing context.  This prevents them from accidentally
// looking like class members in C++.
ParmVarDecl *New =
    CheckParameter(Context.getTranslationUnitDecl(), D.getBeginLoc(),
                   D.getIdentifierLoc(), II, parmDeclType, TInfo, SC);

if (D.isInvalidType())
  New->setInvalidDecl();

assert(S->isFunctionPrototypeScope())((void)0);
assert(S->getFunctionPrototypeDepth() >= 1)((void)0);
New->setScopeInfo(S->getFunctionPrototypeDepth() - 1,
                  S->getNextFunctionPrototypeIndex());

// Add the parameter declaration into this scope.
S->AddDecl(New);
if (II)
  IdResolver.AddDecl(New);

ProcessDeclAttributes(S, New, D);

if (D.getDeclSpec().isModulePrivateSpecified())
  Diag(New->getLocation(), diag::err_module_private_local)
      << 1 << New << SourceRange(D.getDeclSpec().getModulePrivateSpecLoc())
      << FixItHint::CreateRemoval(D.getDeclSpec().getModulePrivateSpecLoc());

if (New->hasAttr<BlocksAttr>()) {
  Diag(New->getLocation(), diag::err_block_on_nonlocal);
}

if (getLangOpts().OpenCL)
  deduceOpenCLAddressSpace(New);

return New;
13813}

13815/// Synthesizes a variable for a parameter arising from a
13816/// typedef.
13817ParmVarDecl *Sema::BuildParmVarDeclForTypedef(DeclContext *DC,
                                            SourceLocation Loc,
                                            QualType T) {
/* FIXME: setting StartLoc == Loc.
   Would it be worth to modify callers so as to provide proper source
   location for the unnamed parameters, embedding the parameter's type? */
ParmVarDecl *Param = ParmVarDecl::Create(Context, DC, Loc, Loc, nullptr,
                              T, Context.getTrivialTypeSourceInfo(T, Loc),
                                         SC_None, nullptr);
Param->setImplicit();
return Param;
13828}

13830void Sema::DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters) {
// Don't diagnose unused-parameter errors in template instantiations; we
// will already have done so in the template itself.
if (inTemplateInstantiation())
  return;

for (const ParmVarDecl *Parameter : Parameters) {
  if (!Parameter->isReferenced() && Parameter->getDeclName() &&
      !Parameter->hasAttr<UnusedAttr>()) {
    Diag(Parameter->getLocation(), diag::warn_unused_parameter)
      << Parameter->getDeclName();
  }
}
13843}

13845void Sema::DiagnoseSizeOfParametersAndReturnValue(
  ArrayRef<ParmVarDecl *> Parameters, QualType ReturnTy, NamedDecl *D) {
if (LangOpts.NumLargeByValueCopy == 0) // No check.
  return;

// Warn if the return value is pass-by-value and larger than the specified
// threshold.
if (!ReturnTy->isDependentType() && ReturnTy.isPODType(Context)) {
  unsigned Size = Context.getTypeSizeInChars(ReturnTy).getQuantity();
  if (Size > LangOpts.NumLargeByValueCopy)
    Diag(D->getLocation(), diag::warn_return_value_size) << D << Size;
}

// Warn if any parameter is pass-by-value and larger than the specified
// threshold.
for (const ParmVarDecl *Parameter : Parameters) {
  QualType T = Parameter->getType();
  if (T->isDependentType() || !T.isPODType(Context))
    continue;
  unsigned Size = Context.getTypeSizeInChars(T).getQuantity();
  if (Size > LangOpts.NumLargeByValueCopy)
    Diag(Parameter->getLocation(), diag::warn_parameter_size)
        << Parameter << Size;
}
13869}

13871ParmVarDecl *Sema::CheckParameter(DeclContext *DC, SourceLocation StartLoc,
                                SourceLocation NameLoc, IdentifierInfo *Name,
                                QualType T, TypeSourceInfo *TSInfo,
                                StorageClass SC) {
// In ARC, infer a lifetime qualifier for appropriate parameter types.
if (getLangOpts().ObjCAutoRefCount &&
    T.getObjCLifetime() == Qualifiers::OCL_None &&
    T->isObjCLifetimeType()) {

  Qualifiers::ObjCLifetime lifetime;

  // Special cases for arrays:
  //   - if it's const, use __unsafe_unretained
  //   - otherwise, it's an error
  if (T->isArrayType()) {
    if (!T.isConstQualified()) {
      if (DelayedDiagnostics.shouldDelayDiagnostics())
        DelayedDiagnostics.add(
            sema::DelayedDiagnostic::makeForbiddenType(
            NameLoc, diag::err_arc_array_param_no_ownership, T, false));
      else
        Diag(NameLoc, diag::err_arc_array_param_no_ownership)
            << TSInfo->getTypeLoc().getSourceRange();
    }
    lifetime = Qualifiers::OCL_ExplicitNone;
  } else {
    lifetime = T->getObjCARCImplicitLifetime();
  }
  T = Context.getLifetimeQualifiedType(T, lifetime);
}

ParmVarDecl *New = ParmVarDecl::Create(Context, DC, StartLoc, NameLoc, Name,
                                       Context.getAdjustedParameterType(T),
                                       TSInfo, SC, nullptr);

// Make a note if we created a new pack in the scope of a lambda, so that
// we know that references to that pack must also be expanded within the
// lambda scope.
if (New->isParameterPack())
  if (auto *LSI = getEnclosingLambda())
    LSI->LocalPacks.push_back(New);

if (New->getType().hasNonTrivialToPrimitiveDestructCUnion() ||
    New->getType().hasNonTrivialToPrimitiveCopyCUnion())
  checkNonTrivialCUnion(New->getType(), New->getLocation(),
                        NTCUC_FunctionParam, NTCUK_Destruct|NTCUK_Copy);

// Parameters can not be abstract class types.
// For record types, this is done by the AbstractClassUsageDiagnoser once
// the class has been completely parsed.
if (!CurContext->isRecord() &&
    RequireNonAbstractType(NameLoc, T, diag::err_abstract_type_in_decl,
                           AbstractParamType))
  New->setInvalidDecl();

// Parameter declarators cannot be interface types. All ObjC objects are
// passed by reference.
if (T->isObjCObjectType()) {
  SourceLocation TypeEndLoc =
      getLocForEndOfToken(TSInfo->getTypeLoc().getEndLoc());
  Diag(NameLoc,
       diag::err_object_cannot_be_passed_returned_by_value) << 1 << T
    << FixItHint::CreateInsertion(TypeEndLoc, "*");
  T = Context.getObjCObjectPointerType(T);
  New->setType(T);
}

// ISO/IEC TR 18037 S6.7.3: "The type of an object with automatic storage
// duration shall not be qualified by an address-space qualifier."
// Since all parameters have automatic store duration, they can not have
// an address space.
if (T.getAddressSpace() != LangAS::Default &&
    // OpenCL allows function arguments declared to be an array of a type
    // to be qualified with an address space.
    !(getLangOpts().OpenCL &&
      (T->isArrayType() || T.getAddressSpace() == LangAS::opencl_private))) {
  Diag(NameLoc, diag::err_arg_with_address_space);
  New->setInvalidDecl();
}

// PPC MMA non-pointer types are not allowed as function argument types.
if (Context.getTargetInfo().getTriple().isPPC64() &&
    CheckPPCMMAType(New->getOriginalType(), New->getLocation())) {
  New->setInvalidDecl();
}

return New;
13958}

13960void Sema::ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
                                         SourceLocation LocAfterDecls) {
DeclaratorChunk::FunctionTypeInfo &FTI = D.getFunctionTypeInfo();

// Verify 6.9.1p6: 'every identifier in the identifier list shall be declared'
// for a K&R function.
if (!FTI.hasPrototype) {
  for (int i = FTI.NumParams; i != 0; /* decrement in loop */) {
    --i;
    if (FTI.Params[i].Param == nullptr) {
      SmallString<256> Code;
      llvm::raw_svector_ostream(Code)
          << "  int " << FTI.Params[i].Ident->getName() << ";\n";
      Diag(FTI.Params[i].IdentLoc, diag::ext_param_not_declared)
          << FTI.Params[i].Ident
          << FixItHint::CreateInsertion(LocAfterDecls, Code);

      // Implicitly declare the argument as type 'int' for lack of a better
      // type.
      AttributeFactory attrs;
      DeclSpec DS(attrs);
      const char* PrevSpec; // unused
      unsigned DiagID; // unused
      DS.SetTypeSpecType(DeclSpec::TST_int, FTI.Params[i].IdentLoc, PrevSpec,
                         DiagID, Context.getPrintingPolicy());
      // Use the identifier location for the type source range.
      DS.SetRangeStart(FTI.Params[i].IdentLoc);
      DS.SetRangeEnd(FTI.Params[i].IdentLoc);
      Declarator ParamD(DS, DeclaratorContext::KNRTypeList);
      ParamD.SetIdentifier(FTI.Params[i].Ident, FTI.Params[i].IdentLoc);
      FTI.Params[i].Param = ActOnParamDeclarator(S, ParamD);
    }
  }
}
13994}

13996Decl *
13997Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Declarator &D,
                            MultiTemplateParamsArg TemplateParameterLists,
                            SkipBodyInfo *SkipBody) {
assert(getCurFunctionDecl() == nullptr && "Function parsing confused")((void)0);
assert(D.isFunctionDeclarator() && "Not a function declarator!")((void)0);
Scope *ParentScope = FnBodyScope->getParent();

// Check if we are in an `omp begin/end declare variant` scope. If we are, and
// we define a non-templated function definition, we will create a declaration
// instead (=BaseFD), and emit the definition with a mangled name afterwards.
// The base function declaration will have the equivalent of an `omp declare
// variant` annotation which specifies the mangled definition as a
// specialization function under the OpenMP context defined as part of the
// `omp begin declare variant`.
SmallVector<FunctionDecl *, 4> Bases;
if (LangOpts.OpenMP && isInOpenMPDeclareVariantScope())
  ActOnStartOfFunctionDefinitionInOpenMPDeclareVariantScope(
      ParentScope, D, TemplateParameterLists, Bases);

D.setFunctionDefinitionKind(FunctionDefinitionKind::Definition);
Decl *DP = HandleDeclarator(ParentScope, D, TemplateParameterLists);
Decl *Dcl = ActOnStartOfFunctionDef(FnBodyScope, DP, SkipBody);

if (!Bases.empty())
  ActOnFinishedFunctionDefinitionInOpenMPDeclareVariantScope(Dcl, Bases);

return Dcl;
14024}

14026void Sema::ActOnFinishInlineFunctionDef(FunctionDecl *D) {
Consumer.HandleInlineFunctionDefinition(D);
14028}

14030static bool
14031ShouldWarnAboutMissingPrototype(const FunctionDecl *FD,
                              const FunctionDecl *&PossiblePrototype) {
// Don't warn about invalid declarations.
if (FD->isInvalidDecl())
  return false;

// Or declarations that aren't global.
if (!FD->isGlobal())
  return false;

// Don't warn about C++ member functions.
if (isa<CXXMethodDecl>(FD))
  return false;

// Don't warn about 'main'.
if (isa<TranslationUnitDecl>(FD->getDeclContext()->getRedeclContext()))
  if (IdentifierInfo *II = FD->getIdentifier())
    if (II->isStr("main") || II->isStr("efi_main"))
      return false;

// Don't warn about inline functions.
if (FD->isInlined())
  return false;

// Don't warn about function templates.
if (FD->getDescribedFunctionTemplate())
  return false;

// Don't warn about function template specializations.
if (FD->isFunctionTemplateSpecialization())
  return false;

// Don't warn for OpenCL kernels.
if (FD->hasAttr<OpenCLKernelAttr>())
  return false;

// Don't warn on explicitly deleted functions.
if (FD->isDeleted())
  return false;

for (const FunctionDecl *Prev = FD->getPreviousDecl();
     Prev; Prev = Prev->getPreviousDecl()) {
  // Ignore any declarations that occur in function or method
  // scope, because they aren't visible from the header.
  if (Prev->getLexicalDeclContext()->isFunctionOrMethod())
    continue;

  PossiblePrototype = Prev;
  return Prev->getType()->isFunctionNoProtoType();
}

return true;
14083}

14085void
14086Sema::CheckForFunctionRedefinition(FunctionDecl *FD,
                                 const FunctionDecl *EffectiveDefinition,
                                 SkipBodyInfo *SkipBody) {
const FunctionDecl *Definition = EffectiveDefinition;
if (!Definition &&
    !FD->isDefined(Definition, /*CheckForPendingFriendDefinition*/ true))
  return;

if (Definition->getFriendObjectKind() != Decl::FOK_None) {
  if (FunctionDecl *OrigDef = Definition->getInstantiatedFromMemberFunction()) {
    if (FunctionDecl *OrigFD = FD->getInstantiatedFromMemberFunction()) {
      // A merged copy of the same function, instantiated as a member of
      // the same class, is OK.
      if (declaresSameEntity(OrigFD, OrigDef) &&
          declaresSameEntity(cast<Decl>(Definition->getLexicalDeclContext()),
                             cast<Decl>(FD->getLexicalDeclContext())))
        return;
    }
  }
}

if (canRedefineFunction(Definition, getLangOpts()))
  return;

// Don't emit an error when this is redefinition of a typo-corrected
// definition.
if (TypoCorrectedFunctionDefinitions.count(Definition))
  return;

// If we don't have a visible definition of the function, and it's inline or
// a template, skip the new definition.
if (SkipBody && !hasVisibleDefinition(Definition) &&
    (Definition->getFormalLinkage() == InternalLinkage ||
     Definition->isInlined() ||
     Definition->getDescribedFunctionTemplate() ||
     Definition->getNumTemplateParameterLists())) {
  SkipBody->ShouldSkip = true;
  SkipBody->Previous = const_cast<FunctionDecl*>(Definition);
  if (auto *TD = Definition->getDescribedFunctionTemplate())
    makeMergedDefinitionVisible(TD);
  makeMergedDefinitionVisible(const_cast<FunctionDecl*>(Definition));
  return;
}

if (getLangOpts().GNUMode && Definition->isInlineSpecified() &&
    Definition->getStorageClass() == SC_Extern)
  Diag(FD->getLocation(), diag::err_redefinition_extern_inline)
      << FD << getLangOpts().CPlusPlus;
else
  Diag(FD->getLocation(), diag::err_redefinition) << FD;

Diag(Definition->getLocation(), diag::note_previous_definition);
FD->setInvalidDecl();
14139}

14141static void RebuildLambdaScopeInfo(CXXMethodDecl *CallOperator,
                                 Sema &S) {
CXXRecordDecl *const LambdaClass = CallOperator->getParent();

LambdaScopeInfo *LSI = S.PushLambdaScope();
LSI->CallOperator = CallOperator;
LSI->Lambda = LambdaClass;
LSI->ReturnType = CallOperator->getReturnType();
const LambdaCaptureDefault LCD = LambdaClass->getLambdaCaptureDefault();

if (LCD == LCD_None)
  LSI->ImpCaptureStyle = CapturingScopeInfo::ImpCap_None;
else if (LCD == LCD_ByCopy)
  LSI->ImpCaptureStyle = CapturingScopeInfo::ImpCap_LambdaByval;
else if (LCD == LCD_ByRef)
  LSI->ImpCaptureStyle = CapturingScopeInfo::ImpCap_LambdaByref;
DeclarationNameInfo DNI = CallOperator->getNameInfo();

LSI->IntroducerRange = DNI.getCXXOperatorNameRange();
LSI->Mutable = !CallOperator->isConst();

// Add the captures to the LSI so they can be noted as already
// captured within tryCaptureVar.
auto I = LambdaClass->field_begin();
for (const auto &C : LambdaClass->captures()) {
  if (C.capturesVariable()) {
    VarDecl *VD = C.getCapturedVar();
    if (VD->isInitCapture())
      S.CurrentInstantiationScope->InstantiatedLocal(VD, VD);
    const bool ByRef = C.getCaptureKind() == LCK_ByRef;
    LSI->addCapture(VD, /*IsBlock*/false, ByRef,
        /*RefersToEnclosingVariableOrCapture*/true, C.getLocation(),
        /*EllipsisLoc*/C.isPackExpansion()
                       ? C.getEllipsisLoc() : SourceLocation(),
        I->getType(), /*Invalid*/false);

  } else if (C.capturesThis()) {
    LSI->addThisCapture(/*Nested*/ false, C.getLocation(), I->getType(),
                        C.getCaptureKind() == LCK_StarThis);
  } else {
    LSI->addVLATypeCapture(C.getLocation(), I->getCapturedVLAType(),
                           I->getType());
  }
  ++I;
}
14186}

14188Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D,
                                  SkipBodyInfo *SkipBody) {
if (!D) {
  // Parsing the function declaration failed in some way. Push on a fake scope
  // anyway so we can try to parse the function body.
  PushFunctionScope();
  PushExpressionEvaluationContext(ExprEvalContexts.back().Context);
  return D;
}

FunctionDecl *FD = nullptr;

if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D))
  FD = FunTmpl->getTemplatedDecl();
else
  FD = cast<FunctionDecl>(D);

// Do not push if it is a lambda because one is already pushed when building
// the lambda in ActOnStartOfLambdaDefinition().
if (!isLambdaCallOperator(FD))
  PushExpressionEvaluationContext(
      FD->isConsteval() ? ExpressionEvaluationContext::ConstantEvaluated
                        : ExprEvalContexts.back().Context);

// Check for defining attributes before the check for redefinition.
if (const auto *Attr = FD->getAttr<AliasAttr>()) {
  Diag(Attr->getLocation(), diag::err_alias_is_definition) << FD << 0;
  FD->dropAttr<AliasAttr>();
  FD->setInvalidDecl();
}
if (const auto *Attr = FD->getAttr<IFuncAttr>()) {
  Diag(Attr->getLocation(), diag::err_alias_is_definition) << FD << 1;
  FD->dropAttr<IFuncAttr>();
  FD->setInvalidDecl();
}

if (auto *Ctor = dyn_cast<CXXConstructorDecl>(FD)) {
  if (Ctor->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&
      Ctor->isDefaultConstructor() &&
      Context.getTargetInfo().getCXXABI().isMicrosoft()) {
    // If this is an MS ABI dllexport default constructor, instantiate any
    // default arguments.
    InstantiateDefaultCtorDefaultArgs(Ctor);
  }
}

// See if this is a redefinition. If 'will have body' (or similar) is already
// set, then these checks were already performed when it was set.
if (!FD->willHaveBody() && !FD->isLateTemplateParsed() &&
    !FD->isThisDeclarationInstantiatedFromAFriendDefinition()) {
  CheckForFunctionRedefinition(FD, nullptr, SkipBody);

  // If we're skipping the body, we're done. Don't enter the scope.
  if (SkipBody && SkipBody->ShouldSkip)
    return D;
}

// Mark this function as "will have a body eventually".  This lets users to
// call e.g. isInlineDefinitionExternallyVisible while we're still parsing
// this function.
FD->setWillHaveBody();

// If we are instantiating a generic lambda call operator, push
// a LambdaScopeInfo onto the function stack.  But use the information
// that's already been calculated (ActOnLambdaExpr) to prime the current
// LambdaScopeInfo.
// When the template operator is being specialized, the LambdaScopeInfo,
// has to be properly restored so that tryCaptureVariable doesn't try
// and capture any new variables. In addition when calculating potential
// captures during transformation of nested lambdas, it is necessary to
// have the LSI properly restored.
if (isGenericLambdaCallOperatorSpecialization(FD)) {
  assert(inTemplateInstantiation() &&((void)0)
         "There should be an active template instantiation on the stack "((void)0)
         "when instantiating a generic lambda!")((void)0);
  RebuildLambdaScopeInfo(cast<CXXMethodDecl>(D), *this);
} else {
  // Enter a new function scope
  PushFunctionScope();
}

// Builtin functions cannot be defined.
if (unsigned BuiltinID = FD->getBuiltinID()) {
  if (!Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID) &&
      !Context.BuiltinInfo.isPredefinedRuntimeFunction(BuiltinID)) {
    Diag(FD->getLocation(), diag::err_builtin_definition) << FD;
    FD->setInvalidDecl();
  }
}

// The return type of a function definition must be complete
// (C99 6.9.1p3, C++ [dcl.fct]p6).
QualType ResultType = FD->getReturnType();
if (!ResultType->isDependentType() && !ResultType->isVoidType() &&
    !FD->isInvalidDecl() &&
    RequireCompleteType(FD->getLocation(), ResultType,
                        diag::err_func_def_incomplete_result))
  FD->setInvalidDecl();

if (FnBodyScope)
  PushDeclContext(FnBodyScope, FD);

// Check the validity of our function parameters
CheckParmsForFunctionDef(FD->parameters(),
                         /*CheckParameterNames=*/true);

// Add non-parameter declarations already in the function to the current
// scope.
if (FnBodyScope) {
  for (Decl *NPD : FD->decls()) {
    auto *NonParmDecl = dyn_cast<NamedDecl>(NPD);
    if (!NonParmDecl)
      continue;
    assert(!isa<ParmVarDecl>(NonParmDecl) &&((void)0)
           "parameters should not be in newly created FD yet")((void)0);

    // If the decl has a name, make it accessible in the current scope.
    if (NonParmDecl->getDeclName())
      PushOnScopeChains(NonParmDecl, FnBodyScope, /*AddToContext=*/false);

    // Similarly, dive into enums and fish their constants out, making them
    // accessible in this scope.
    if (auto *ED = dyn_cast<EnumDecl>(NonParmDecl)) {
      for (auto *EI : ED->enumerators())
        PushOnScopeChains(EI, FnBodyScope, /*AddToContext=*/false);
    }
  }
}

// Introduce our parameters into the function scope
for (auto Param : FD->parameters()) {
  Param->setOwningFunction(FD);

  // If this has an identifier, add it to the scope stack.
  if (Param->getIdentifier() && FnBodyScope) {
    CheckShadow(FnBodyScope, Param);

    PushOnScopeChains(Param, FnBodyScope);
  }
}

// Ensure that the function's exception specification is instantiated.
if (const FunctionProtoType *FPT = FD->getType()->getAs<FunctionProtoType>())
  ResolveExceptionSpec(D->getLocation(), FPT);

// dllimport cannot be applied to non-inline function definitions.
if (FD->hasAttr<DLLImportAttr>() && !FD->isInlined() &&
    !FD->isTemplateInstantiation()) {
  assert(!FD->hasAttr<DLLExportAttr>())((void)0);
  Diag(FD->getLocation(), diag::err_attribute_dllimport_function_definition);
  FD->setInvalidDecl();
  return D;
}
// We want to attach documentation to original Decl (which might be
// a function template).
ActOnDocumentableDecl(D);
if (getCurLexicalContext()->isObjCContainer() &&
    getCurLexicalContext()->getDeclKind() != Decl::ObjCCategoryImpl &&
    getCurLexicalContext()->getDeclKind() != Decl::ObjCImplementation)
  Diag(FD->getLocation(), diag::warn_function_def_in_objc_container);

return D;
14350}

14352/// Given the set of return statements within a function body,
14353/// compute the variables that are subject to the named return value
14354/// optimization.
14355///
14356/// Each of the variables that is subject to the named return value
14357/// optimization will be marked as NRVO variables in the AST, and any
14358/// return statement that has a marked NRVO variable as its NRVO candidate can
14359/// use the named return value optimization.
14360///
14361/// This function applies a very simplistic algorithm for NRVO: if every return
14362/// statement in the scope of a variable has the same NRVO candidate, that
14363/// candidate is an NRVO variable.
14364void Sema::computeNRVO(Stmt *Body, FunctionScopeInfo *Scope) {
ReturnStmt **Returns = Scope->Returns.data();

for (unsigned I = 0, E = Scope->Returns.size(); I != E; ++I) {
  if (const VarDecl *NRVOCandidate = Returns[I]->getNRVOCandidate()) {
    if (!NRVOCandidate->isNRVOVariable())
      Returns[I]->setNRVOCandidate(nullptr);
  }
}
14373}

14375bool Sema::canDelayFunctionBody(const Declarator &D) {
// We can't delay parsing the body of a constexpr function template (yet).
if (D.getDeclSpec().hasConstexprSpecifier())
  return false;

// We can't delay parsing the body of a function template with a deduced
// return type (yet).
if (D.getDeclSpec().hasAutoTypeSpec()) {
  // If the placeholder introduces a non-deduced trailing return type,
  // we can still delay parsing it.
  if (D.getNumTypeObjects()) {
    const auto &Outer = D.getTypeObject(D.getNumTypeObjects() - 1);
    if (Outer.Kind == DeclaratorChunk::Function &&
        Outer.Fun.hasTrailingReturnType()) {
      QualType Ty = GetTypeFromParser(Outer.Fun.getTrailingReturnType());
      return Ty.isNull() || !Ty->isUndeducedType();
    }
  }
  return false;
}

return true;
14397}

14399bool Sema::canSkipFunctionBody(Decl *D) {
// We cannot skip the body of a function (or function template) which is
// constexpr, since we may need to evaluate its body in order to parse the
// rest of the file.
// We cannot skip the body of a function with an undeduced return type,
// because any callers of that function need to know the type.
if (const FunctionDecl *FD = D->getAsFunction()) {
  if (FD->isConstexpr())
    return false;
  // We can't simply call Type::isUndeducedType here, because inside template
  // auto can be deduced to a dependent type, which is not considered
  // "undeduced".
  if (FD->getReturnType()->getContainedDeducedType())
    return false;
}
return Consumer.shouldSkipFunctionBody(D);
14415}

14417Decl *Sema::ActOnSkippedFunctionBody(Decl *Decl) {
if (!Decl)
  return nullptr;
if (FunctionDecl *FD = Decl->getAsFunction())
  FD->setHasSkippedBody();
else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(Decl))
  MD->setHasSkippedBody();
return Decl;
14425}

14427Decl *Sema::ActOnFinishFunctionBody(Decl *D, Stmt *BodyArg) {
return ActOnFinishFunctionBody(D, BodyArg, false);
14429}

14431/// RAII object that pops an ExpressionEvaluationContext when exiting a function
14432/// body.
14433class ExitFunctionBodyRAII {
14434public:
ExitFunctionBodyRAII(Sema &S, bool IsLambda) : S(S), IsLambda(IsLambda) {}
~ExitFunctionBodyRAII() {
  if (!IsLambda)
    S.PopExpressionEvaluationContext();
}

14441private:
Sema &S;
bool IsLambda = false;
14444};

14446static void diagnoseImplicitlyRetainedSelf(Sema &S) {
llvm::DenseMap<const BlockDecl *, bool> EscapeInfo;

auto IsOrNestedInEscapingBlock = [&](const BlockDecl *BD) {
  if (EscapeInfo.count(BD))
    return EscapeInfo[BD];

  bool R = false;
  const BlockDecl *CurBD = BD;

  do {
    R = !CurBD->doesNotEscape();
    if (R)
      break;
    CurBD = CurBD->getParent()->getInnermostBlockDecl();
  } while (CurBD);

  return EscapeInfo[BD] = R;
};

// If the location where 'self' is implicitly retained is inside a escaping
// block, emit a diagnostic.
for (const std::pair<SourceLocation, const BlockDecl *> &P :
     S.ImplicitlyRetainedSelfLocs)
  if (IsOrNestedInEscapingBlock(P.second))
    S.Diag(P.first, diag::warn_implicitly_retains_self)
        << FixItHint::CreateInsertion(P.first, "self->");
14473}

14475Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body,
                                  bool IsInstantiation) {
FunctionScopeInfo *FSI = getCurFunction();
FunctionDecl *FD = dcl ? dcl->getAsFunction() : nullptr;
1
Assuming 'dcl' is null→
2
←
'?' condition is false→
3
←
'FD' initialized to a null pointer value→

if (FSI->UsesFPIntrin && !FD->hasAttr<StrictFPAttr>())
4
←
Assuming field 'UsesFPIntrin' is true→
5
←
Called C++ object pointer is null
  FD->addAttr(StrictFPAttr::CreateImplicit(Context));

sema::AnalysisBasedWarnings::Policy WP = AnalysisWarnings.getDefaultPolicy();
sema::AnalysisBasedWarnings::Policy *ActivePolicy = nullptr;

if (getLangOpts().Coroutines && FSI->isCoroutine())
  CheckCompletedCoroutineBody(FD, Body);

// Do not call PopExpressionEvaluationContext() if it is a lambda because one
// is already popped when finishing the lambda in BuildLambdaExpr(). This is
// meant to pop the context added in ActOnStartOfFunctionDef().
ExitFunctionBodyRAII ExitRAII(*this, isLambdaCallOperator(FD));

if (FD) {
  FD->setBody(Body);
  FD->setWillHaveBody(false);

  if (getLangOpts().CPlusPlus14) {
    if (!FD->isInvalidDecl() && Body && !FD->isDependentContext() &&
        FD->getReturnType()->isUndeducedType()) {
      // If the function has a deduced result type but contains no 'return'
      // statements, the result type as written must be exactly 'auto', and
      // the deduced result type is 'void'.
      if (!FD->getReturnType()->getAs<AutoType>()) {
        Diag(dcl->getLocation(), diag::err_auto_fn_no_return_but_not_auto)
            << FD->getReturnType();
        FD->setInvalidDecl();
      } else {
        // Substitute 'void' for the 'auto' in the type.
        TypeLoc ResultType = getReturnTypeLoc(FD);
        Context.adjustDeducedFunctionResultType(
            FD, SubstAutoType(ResultType.getType(), Context.VoidTy));
      }
    }
  } else if (getLangOpts().CPlusPlus11 && isLambdaCallOperator(FD)) {
    // In C++11, we don't use 'auto' deduction rules for lambda call
    // operators because we don't support return type deduction.
    auto *LSI = getCurLambda();
    if (LSI->HasImplicitReturnType) {
      deduceClosureReturnType(*LSI);

      // C++11 [expr.prim.lambda]p4:
      //   [...] if there are no return statements in the compound-statement
      //   [the deduced type is] the type void
      QualType RetType =
          LSI->ReturnType.isNull() ? Context.VoidTy : LSI->ReturnType;

      // Update the return type to the deduced type.
      const auto *Proto = FD->getType()->castAs<FunctionProtoType>();
      FD->setType(Context.getFunctionType(RetType, Proto->getParamTypes(),
                                          Proto->getExtProtoInfo()));
    }
  }

  // If the function implicitly returns zero (like 'main') or is naked,
  // don't complain about missing return statements.
  if (FD->hasImplicitReturnZero() || FD->hasAttr<NakedAttr>())
    WP.disableCheckFallThrough();

  // MSVC permits the use of pure specifier (=0) on function definition,
  // defined at class scope, warn about this non-standard construct.
  if (getLangOpts().MicrosoftExt && FD->isPure() && !FD->isOutOfLine())
    Diag(FD->getLocation(), diag::ext_pure_function_definition);

  if (!FD->isInvalidDecl()) {
    // Don't diagnose unused parameters of defaulted or deleted functions.
    if (!FD->isDeleted() && !FD->isDefaulted() && !FD->hasSkippedBody())
      DiagnoseUnusedParameters(FD->parameters());
    DiagnoseSizeOfParametersAndReturnValue(FD->parameters(),
                                           FD->getReturnType(), FD);

    // If this is a structor, we need a vtable.
    if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(FD))
      MarkVTableUsed(FD->getLocation(), Constructor->getParent());
    else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(FD))
      MarkVTableUsed(FD->getLocation(), Destructor->getParent());

    // Try to apply the named return value optimization. We have to check
    // if we can do this here because lambdas keep return statements around
    // to deduce an implicit return type.
    if (FD->getReturnType()->isRecordType() &&
        (!getLangOpts().CPlusPlus || !FD->isDependentContext()))
      computeNRVO(Body, FSI);
  }

  // GNU warning -Wmissing-prototypes:
  //   Warn if a global function is defined without a previous
  //   prototype declaration. This warning is issued even if the
  //   definition itself provides a prototype. The aim is to detect
  //   global functions that fail to be declared in header files.
  const FunctionDecl *PossiblePrototype = nullptr;
  if (ShouldWarnAboutMissingPrototype(FD, PossiblePrototype)) {
    Diag(FD->getLocation(), diag::warn_missing_prototype) << FD;

    if (PossiblePrototype) {
      // We found a declaration that is not a prototype,
      // but that could be a zero-parameter prototype
      if (TypeSourceInfo *TI = PossiblePrototype->getTypeSourceInfo()) {
        TypeLoc TL = TI->getTypeLoc();
        if (FunctionNoProtoTypeLoc FTL = TL.getAs<FunctionNoProtoTypeLoc>())
          Diag(PossiblePrototype->getLocation(),
               diag::note_declaration_not_a_prototype)
              << (FD->getNumParams() != 0)
              << (FD->getNumParams() == 0
                      ? FixItHint::CreateInsertion(FTL.getRParenLoc(), "void")
                      : FixItHint{});
      }
    } else {
      // Returns true if the token beginning at this Loc is `const`.
      auto isLocAtConst = [&](SourceLocation Loc, const SourceManager &SM,
                              const LangOptions &LangOpts) {
        std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(Loc);
        if (LocInfo.first.isInvalid())
          return false;

        bool Invalid = false;
        StringRef Buffer = SM.getBufferData(LocInfo.first, &Invalid);
        if (Invalid)
          return false;

        if (LocInfo.second > Buffer.size())
          return false;

        const char *LexStart = Buffer.data() + LocInfo.second;
        StringRef StartTok(LexStart, Buffer.size() - LocInfo.second);

        return StartTok.consume_front("const") &&
               (StartTok.empty() || isWhitespace(StartTok[0]) ||
                StartTok.startswith("/*") || StartTok.startswith("//"));
      };

      auto findBeginLoc = [&]() {
        // If the return type has `const` qualifier, we want to insert
        // `static` before `const` (and not before the typename).
        if ((FD->getReturnType()->isAnyPointerType() &&
             FD->getReturnType()->getPointeeType().isConstQualified()) ||
            FD->getReturnType().isConstQualified()) {
          // But only do this if we can determine where the `const` is.

          if (isLocAtConst(FD->getBeginLoc(), getSourceManager(),
                           getLangOpts()))

            return FD->getBeginLoc();
        }
        return FD->getTypeSpecStartLoc();
      };
      Diag(FD->getTypeSpecStartLoc(), diag::note_static_for_internal_linkage)
          << /* function */ 1
          << (FD->getStorageClass() == SC_None
                  ? FixItHint::CreateInsertion(findBeginLoc(), "static ")
                  : FixItHint{});
    }

    // GNU warning -Wstrict-prototypes
    //   Warn if K&R function is defined without a previous declaration.
    //   This warning is issued only if the definition itself does not provide
    //   a prototype. Only K&R definitions do not provide a prototype.
    if (!FD->hasWrittenPrototype()) {
      TypeSourceInfo *TI = FD->getTypeSourceInfo();
      TypeLoc TL = TI->getTypeLoc();
      FunctionTypeLoc FTL = TL.getAsAdjusted<FunctionTypeLoc>();
      Diag(FTL.getLParenLoc(), diag::warn_strict_prototypes) << 2;
    }
  }

  // Warn on CPUDispatch with an actual body.
  if (FD->isMultiVersion() && FD->hasAttr<CPUDispatchAttr>() && Body)
    if (const auto *CmpndBody = dyn_cast<CompoundStmt>(Body))
      if (!CmpndBody->body_empty())
        Diag(CmpndBody->body_front()->getBeginLoc(),
             diag::warn_dispatch_body_ignored);

  if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
    const CXXMethodDecl *KeyFunction;
    if (MD->isOutOfLine() && (MD = MD->getCanonicalDecl()) &&
        MD->isVirtual() &&
        (KeyFunction = Context.getCurrentKeyFunction(MD->getParent())) &&
        MD == KeyFunction->getCanonicalDecl()) {
      // Update the key-function state if necessary for this ABI.
      if (FD->isInlined() &&
          !Context.getTargetInfo().getCXXABI().canKeyFunctionBeInline()) {
        Context.setNonKeyFunction(MD);

        // If the newly-chosen key function is already defined, then we
        // need to mark the vtable as used retroactively.
        KeyFunction = Context.getCurrentKeyFunction(MD->getParent());
        const FunctionDecl *Definition;
        if (KeyFunction && KeyFunction->isDefined(Definition))
          MarkVTableUsed(Definition->getLocation(), MD->getParent(), true);
      } else {
        // We just defined they key function; mark the vtable as used.
        MarkVTableUsed(FD->getLocation(), MD->getParent(), true);
      }
    }
  }

  assert((FD == getCurFunctionDecl() || getCurLambda()->CallOperator == FD) &&((void)0)
         "Function parsing confused")((void)0);
} else if (ObjCMethodDecl *MD = dyn_cast_or_null<ObjCMethodDecl>(dcl)) {
  assert(MD == getCurMethodDecl() && "Method parsing confused")((void)0);
  MD->setBody(Body);
  if (!MD->isInvalidDecl()) {
    DiagnoseSizeOfParametersAndReturnValue(MD->parameters(),
                                           MD->getReturnType(), MD);

    if (Body)
      computeNRVO(Body, FSI);
  }
  if (FSI->ObjCShouldCallSuper) {
    Diag(MD->getEndLoc(), diag::warn_objc_missing_super_call)
        << MD->getSelector().getAsString();
    FSI->ObjCShouldCallSuper = false;
  }
  if (FSI->ObjCWarnForNoDesignatedInitChain) {
    const ObjCMethodDecl *InitMethod = nullptr;
    bool isDesignated =
        MD->isDesignatedInitializerForTheInterface(&InitMethod);
    assert(isDesignated && InitMethod)((void)0);
    (void)isDesignated;

    auto superIsNSObject = [&](const ObjCMethodDecl *MD) {
      auto IFace = MD->getClassInterface();
      if (!IFace)
        return false;
      auto SuperD = IFace->getSuperClass();
      if (!SuperD)
        return false;
      return SuperD->getIdentifier() ==
          NSAPIObj->getNSClassId(NSAPI::ClassId_NSObject);
    };
    // Don't issue this warning for unavailable inits or direct subclasses
    // of NSObject.
    if (!MD->isUnavailable() && !superIsNSObject(MD)) {
      Diag(MD->getLocation(),
           diag::warn_objc_designated_init_missing_super_call);
      Diag(InitMethod->getLocation(),
           diag::note_objc_designated_init_marked_here);
    }
    FSI->ObjCWarnForNoDesignatedInitChain = false;
  }
  if (FSI->ObjCWarnForNoInitDelegation) {
    // Don't issue this warning for unavaialable inits.
    if (!MD->isUnavailable())
      Diag(MD->getLocation(),
           diag::warn_objc_secondary_init_missing_init_call);
    FSI->ObjCWarnForNoInitDelegation = false;
  }

  diagnoseImplicitlyRetainedSelf(*this);
} else {
  // Parsing the function declaration failed in some way. Pop the fake scope
  // we pushed on.
  PopFunctionScopeInfo(ActivePolicy, dcl);
  return nullptr;
}

if (Body && FSI->HasPotentialAvailabilityViolations)
  DiagnoseUnguardedAvailabilityViolations(dcl);

assert(!FSI->ObjCShouldCallSuper &&((void)0)
       "This should only be set for ObjC methods, which should have been "((void)0)
       "handled in the block above.")((void)0);

// Verify and clean out per-function state.
if (Body && (!FD || !FD->isDefaulted())) {
  // C++ constructors that have function-try-blocks can't have return
  // statements in the handlers of that block. (C++ [except.handle]p14)
  // Verify this.
  if (FD && isa<CXXConstructorDecl>(FD) && isa<CXXTryStmt>(Body))
    DiagnoseReturnInConstructorExceptionHandler(cast<CXXTryStmt>(Body));

  // Verify that gotos and switch cases don't jump into scopes illegally.
  if (FSI->NeedsScopeChecking() &&
      !PP.isCodeCompletionEnabled())
    DiagnoseInvalidJumps(Body);

  if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(dcl)) {
    if (!Destructor->getParent()->isDependentType())
      CheckDestructor(Destructor);

    MarkBaseAndMemberDestructorsReferenced(Destructor->getLocation(),
                                           Destructor->getParent());
  }

  // If any errors have occurred, clear out any temporaries that may have
  // been leftover. This ensures that these temporaries won't be picked up for
  // deletion in some later function.
  if (hasUncompilableErrorOccurred() ||
      getDiagnostics().getSuppressAllDiagnostics()) {
    DiscardCleanupsInEvaluationContext();
  }
  if (!hasUncompilableErrorOccurred() &&
      !isa<FunctionTemplateDecl>(dcl)) {
    // Since the body is valid, issue any analysis-based warnings that are
    // enabled.
    ActivePolicy = &WP;
  }

  if (!IsInstantiation && FD && FD->isConstexpr() && !FD->isInvalidDecl() &&
      !CheckConstexprFunctionDefinition(FD, CheckConstexprKind::Diagnose))
    FD->setInvalidDecl();

  if (FD && FD->hasAttr<NakedAttr>()) {
    for (const Stmt *S : Body->children()) {
      // Allow local register variables without initializer as they don't
      // require prologue.
      bool RegisterVariables = false;
      if (auto *DS = dyn_cast<DeclStmt>(S)) {
        for (const auto *Decl : DS->decls()) {
          if (const auto *Var = dyn_cast<VarDecl>(Decl)) {
            RegisterVariables =
                Var->hasAttr<AsmLabelAttr>() && !Var->hasInit();
            if (!RegisterVariables)
              break;
          }
        }
      }
      if (RegisterVariables)
        continue;
      if (!isa<AsmStmt>(S) && !isa<NullStmt>(S)) {
        Diag(S->getBeginLoc(), diag::err_non_asm_stmt_in_naked_function);
        Diag(FD->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
        FD->setInvalidDecl();
        break;
      }
    }
  }

  assert(ExprCleanupObjects.size() ==((void)0)
             ExprEvalContexts.back().NumCleanupObjects &&((void)0)
         "Leftover temporaries in function")((void)0);
  assert(!Cleanup.exprNeedsCleanups() && "Unaccounted cleanups in function")((void)0);
  assert(MaybeODRUseExprs.empty() &&((void)0)
         "Leftover expressions for odr-use checking")((void)0);
}

if (!IsInstantiation)
  PopDeclContext();

PopFunctionScopeInfo(ActivePolicy, dcl);
// If any errors have occurred, clear out any temporaries that may have
// been leftover. This ensures that these temporaries won't be picked up for
// deletion in some later function.
if (hasUncompilableErrorOccurred()) {
  DiscardCleanupsInEvaluationContext();
}

if (FD && (LangOpts.OpenMP || LangOpts.CUDA || LangOpts.SYCLIsDevice)) {
  auto ES = getEmissionStatus(FD);
  if (ES == Sema::FunctionEmissionStatus::Emitted ||
      ES == Sema::FunctionEmissionStatus::Unknown)
    DeclsToCheckForDeferredDiags.insert(FD);
}

return dcl;
14836}

14838/// When we finish delayed parsing of an attribute, we must attach it to the
14839/// relevant Decl.
14840void Sema::ActOnFinishDelayedAttribute(Scope *S, Decl *D,
                                     ParsedAttributes &Attrs) {
// Always attach attributes to the underlying decl.
if (TemplateDecl *TD = dyn_cast<TemplateDecl>(D))
  D = TD->getTemplatedDecl();
ProcessDeclAttributeList(S, D, Attrs);

if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(D))
  if (Method->isStatic())
    checkThisInStaticMemberFunctionAttributes(Method);
14850}

14852/// ImplicitlyDefineFunction - An undeclared identifier was used in a function
14853/// call, forming a call to an implicitly defined function (per C99 6.5.1p2).
14854NamedDecl *Sema::ImplicitlyDefineFunction(SourceLocation Loc,
                                        IdentifierInfo &II, Scope *S) {
// Find the scope in which the identifier is injected and the corresponding
// DeclContext.
// FIXME: C89 does not say what happens if there is no enclosing block scope.
// In that case, we inject the declaration into the translation unit scope
// instead.
Scope *BlockScope = S;
while (!BlockScope->isCompoundStmtScope() && BlockScope->getParent())
  BlockScope = BlockScope->getParent();

Scope *ContextScope = BlockScope;
while (!ContextScope->getEntity())
  ContextScope = ContextScope->getParent();
ContextRAII SavedContext(*this, ContextScope->getEntity());

// Before we produce a declaration for an implicitly defined
// function, see whether there was a locally-scoped declaration of
// this name as a function or variable. If so, use that
// (non-visible) declaration, and complain about it.
NamedDecl *ExternCPrev = findLocallyScopedExternCDecl(&II);
if (ExternCPrev) {
  // We still need to inject the function into the enclosing block scope so
  // that later (non-call) uses can see it.
  PushOnScopeChains(ExternCPrev, BlockScope, /*AddToContext*/false);

  // C89 footnote 38:
  //   If in fact it is not defined as having type "function returning int",
  //   the behavior is undefined.
  if (!isa<FunctionDecl>(ExternCPrev) ||
      !Context.typesAreCompatible(
          cast<FunctionDecl>(ExternCPrev)->getType(),
          Context.getFunctionNoProtoType(Context.IntTy))) {
    Diag(Loc, diag::ext_use_out_of_scope_declaration)
        << ExternCPrev << !getLangOpts().C99;
    Diag(ExternCPrev->getLocation(), diag::note_previous_declaration);
    return ExternCPrev;
  }
}

// Extension in C99.  Legal in C90, but warn about it.
unsigned diag_id;
if (II.getName().startswith("__builtin_"))
  diag_id = diag::warn_builtin_unknown;
// OpenCL v2.0 s6.9.u - Implicit function declaration is not supported.
else if (getLangOpts().OpenCL)
  diag_id = diag::err_opencl_implicit_function_decl;
else if (getLangOpts().C99)
  diag_id = diag::ext_implicit_function_decl;
else
  diag_id = diag::warn_implicit_function_decl;
Diag(Loc, diag_id) << &II;

// If we found a prior declaration of this function, don't bother building
// another one. We've already pushed that one into scope, so there's nothing
// more to do.
if (ExternCPrev)
  return ExternCPrev;

// Because typo correction is expensive, only do it if the implicit
// function declaration is going to be treated as an error.
if (Diags.getDiagnosticLevel(diag_id, Loc) >= DiagnosticsEngine::Error) {
  TypoCorrection Corrected;
  DeclFilterCCC<FunctionDecl> CCC{};
  if (S && (Corrected =
                CorrectTypo(DeclarationNameInfo(&II, Loc), LookupOrdinaryName,
                            S, nullptr, CCC, CTK_NonError)))
    diagnoseTypo(Corrected, PDiag(diag::note_function_suggestion),
                 /*ErrorRecovery*/false);
}

// Set a Declarator for the implicit definition: int foo();
const char *Dummy;
AttributeFactory attrFactory;
DeclSpec DS(attrFactory);
unsigned DiagID;
bool Error = DS.SetTypeSpecType(DeclSpec::TST_int, Loc, Dummy, DiagID,
                                Context.getPrintingPolicy());
(void)Error; // Silence warning.
assert(!Error && "Error setting up implicit decl!")((void)0);
SourceLocation NoLoc;
Declarator D(DS, DeclaratorContext::Block);
D.AddTypeInfo(DeclaratorChunk::getFunction(/*HasProto=*/false,
                                           /*IsAmbiguous=*/false,
                                           /*LParenLoc=*/NoLoc,
                                           /*Params=*/nullptr,
                                           /*NumParams=*/0,
                                           /*EllipsisLoc=*/NoLoc,
                                           /*RParenLoc=*/NoLoc,
                                           /*RefQualifierIsLvalueRef=*/true,
                                           /*RefQualifierLoc=*/NoLoc,
                                           /*MutableLoc=*/NoLoc, EST_None,
                                           /*ESpecRange=*/SourceRange(),
                                           /*Exceptions=*/nullptr,
                                           /*ExceptionRanges=*/nullptr,
                                           /*NumExceptions=*/0,
                                           /*NoexceptExpr=*/nullptr,
                                           /*ExceptionSpecTokens=*/nullptr,
                                           /*DeclsInPrototype=*/None, Loc,
                                           Loc, D),
              std::move(DS.getAttributes()), SourceLocation());
D.SetIdentifier(&II, Loc);

// Insert this function into the enclosing block scope.
FunctionDecl *FD = cast<FunctionDecl>(ActOnDeclarator(BlockScope, D));
FD->setImplicit();

AddKnownFunctionAttributes(FD);

return FD;
14964}

14966/// If this function is a C++ replaceable global allocation function
14967/// (C++2a [basic.stc.dynamic.allocation], C++2a [new.delete]),
14968/// adds any function attributes that we know a priori based on the standard.
14969///
14970/// We need to check for duplicate attributes both here and where user-written
14971/// attributes are applied to declarations.
14972void Sema::AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(
  FunctionDecl *FD) {
if (FD->isInvalidDecl())
  return;

if (FD->getDeclName().getCXXOverloadedOperator() != OO_New &&
    FD->getDeclName().getCXXOverloadedOperator() != OO_Array_New)
  return;

Optional<unsigned> AlignmentParam;
bool IsNothrow = false;
if (!FD->isReplaceableGlobalAllocationFunction(&AlignmentParam, &IsNothrow))
  return;

// C++2a [basic.stc.dynamic.allocation]p4:
//   An allocation function that has a non-throwing exception specification
//   indicates failure by returning a null pointer value. Any other allocation
//   function never returns a null pointer value and indicates failure only by
//   throwing an exception [...]
if (!IsNothrow && !FD->hasAttr<ReturnsNonNullAttr>())
  FD->addAttr(ReturnsNonNullAttr::CreateImplicit(Context, FD->getLocation()));

// C++2a [basic.stc.dynamic.allocation]p2:
//   An allocation function attempts to allocate the requested amount of
//   storage. [...] If the request succeeds, the value returned by a
//   replaceable allocation function is a [...] pointer value p0 different
//   from any previously returned value p1 [...]
//
// However, this particular information is being added in codegen,
// because there is an opt-out switch for it (-fno-assume-sane-operator-new)

// C++2a [basic.stc.dynamic.allocation]p2:
//   An allocation function attempts to allocate the requested amount of
//   storage. If it is successful, it returns the address of the start of a
//   block of storage whose length in bytes is at least as large as the
//   requested size.
if (!FD->hasAttr<AllocSizeAttr>()) {
  FD->addAttr(AllocSizeAttr::CreateImplicit(
      Context, /*ElemSizeParam=*/ParamIdx(1, FD),
      /*NumElemsParam=*/ParamIdx(), FD->getLocation()));
}

// C++2a [basic.stc.dynamic.allocation]p3:
//   For an allocation function [...], the pointer returned on a successful
//   call shall represent the address of storage that is aligned as follows:
//   (3.1) If the allocation function takes an argument of type
//         std​::​align_­val_­t, the storage will have the alignment
//         specified by the value of this argument.
if (AlignmentParam.hasValue() && !FD->hasAttr<AllocAlignAttr>()) {
  FD->addAttr(AllocAlignAttr::CreateImplicit(
      Context, ParamIdx(AlignmentParam.getValue(), FD), FD->getLocation()));
}

// FIXME:
// C++2a [basic.stc.dynamic.allocation]p3:
//   For an allocation function [...], the pointer returned on a successful
//   call shall represent the address of storage that is aligned as follows:
//   (3.2) Otherwise, if the allocation function is named operator new[],
//         the storage is aligned for any object that does not have
//         new-extended alignment ([basic.align]) and is no larger than the
//         requested size.
//   (3.3) Otherwise, the storage is aligned for any object that does not
//         have new-extended alignment and is of the requested size.
15035}

15037/// Adds any function attributes that we know a priori based on
15038/// the declaration of this function.
15039///
15040/// These attributes can apply both to implicitly-declared builtins
15041/// (like __builtin___printf_chk) or to library-declared functions
15042/// like NSLog or printf.
15043///
15044/// We need to check for duplicate attributes both here and where user-written
15045/// attributes are applied to declarations.
15046void Sema::AddKnownFunctionAttributes(FunctionDecl *FD) {
if (FD->isInvalidDecl())
  return;

// If this is a built-in function, map its builtin attributes to
// actual attributes.
if (unsigned BuiltinID = FD->getBuiltinID()) {
  // Handle printf-formatting attributes.
  unsigned FormatIdx;
  bool HasVAListArg;
  if (Context.BuiltinInfo.isPrintfLike(BuiltinID, FormatIdx, HasVAListArg)) {
    if (!FD->hasAttr<FormatAttr>()) {
      const char *fmt = "printf";
      unsigned int NumParams = FD->getNumParams();
      if (FormatIdx < NumParams && // NumParams may be 0 (e.g. vfprintf)
          FD->getParamDecl(FormatIdx)->getType()->isObjCObjectPointerType())
        fmt = "NSString";
      FD->addAttr(FormatAttr::CreateImplicit(Context,
                                             &Context.Idents.get(fmt),
                                             FormatIdx+1,
                                             HasVAListArg ? 0 : FormatIdx+2,
                                             FD->getLocation()));
    }
  }
  if (Context.BuiltinInfo.isScanfLike(BuiltinID, FormatIdx,
                                           HasVAListArg)) {
   if (!FD->hasAttr<FormatAttr>())
     FD->addAttr(FormatAttr::CreateImplicit(Context,
                                            &Context.Idents.get("scanf"),
                                            FormatIdx+1,
                                            HasVAListArg ? 0 : FormatIdx+2,
                                            FD->getLocation()));
  }

  // Handle automatically recognized callbacks.
  SmallVector<int, 4> Encoding;
  if (!FD->hasAttr<CallbackAttr>() &&
      Context.BuiltinInfo.performsCallback(BuiltinID, Encoding))
    FD->addAttr(CallbackAttr::CreateImplicit(
        Context, Encoding.data(), Encoding.size(), FD->getLocation()));

  // Mark const if we don't care about errno and that is the only thing
  // preventing the function from being const. This allows IRgen to use LLVM
  // intrinsics for such functions.
  if (!getLangOpts().MathErrno && !FD->hasAttr<ConstAttr>() &&
      Context.BuiltinInfo.isConstWithoutErrno(BuiltinID))
    FD->addAttr(ConstAttr::CreateImplicit(Context, FD->getLocation()));

  // We make "fma" on some platforms const because we know it does not set
  // errno in those environments even though it could set errno based on the
  // C standard.
  const llvm::Triple &Trip = Context.getTargetInfo().getTriple();
  if ((Trip.isGNUEnvironment() || Trip.isAndroid() || Trip.isOSMSVCRT()) &&
      !FD->hasAttr<ConstAttr>()) {
    switch (BuiltinID) {
    case Builtin::BI__builtin_fma:
    case Builtin::BI__builtin_fmaf:
    case Builtin::BI__builtin_fmal:
    case Builtin::BIfma:
    case Builtin::BIfmaf:
    case Builtin::BIfmal:
      FD->addAttr(ConstAttr::CreateImplicit(Context, FD->getLocation()));
      break;
    default:
      break;
    }
  }

  if (Context.BuiltinInfo.isReturnsTwice(BuiltinID) &&
      !FD->hasAttr<ReturnsTwiceAttr>())
    FD->addAttr(ReturnsTwiceAttr::CreateImplicit(Context,
                                       FD->getLocation()));
  if (Context.BuiltinInfo.isNoThrow(BuiltinID) && !FD->hasAttr<NoThrowAttr>())
    FD->addAttr(NoThrowAttr::CreateImplicit(Context, FD->getLocation()));
  if (Context.BuiltinInfo.isPure(BuiltinID) && !FD->hasAttr<PureAttr>())
    FD->addAttr(PureAttr::CreateImplicit(Context, FD->getLocation()));
  if (Context.BuiltinInfo.isConst(BuiltinID) && !FD->hasAttr<ConstAttr>())
    FD->addAttr(ConstAttr::CreateImplicit(Context, FD->getLocation()));
  if (getLangOpts().CUDA && Context.BuiltinInfo.isTSBuiltin(BuiltinID) &&
      !FD->hasAttr<CUDADeviceAttr>() && !FD->hasAttr<CUDAHostAttr>()) {
    // Add the appropriate attribute, depending on the CUDA compilation mode
    // and which target the builtin belongs to. For example, during host
    // compilation, aux builtins are __device__, while the rest are __host__.
    if (getLangOpts().CUDAIsDevice !=
        Context.BuiltinInfo.isAuxBuiltinID(BuiltinID))
      FD->addAttr(CUDADeviceAttr::CreateImplicit(Context, FD->getLocation()));
    else
      FD->addAttr(CUDAHostAttr::CreateImplicit(Context, FD->getLocation()));
  }
}

AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(FD);

// If C++ exceptions are enabled but we are told extern "C" functions cannot
// throw, add an implicit nothrow attribute to any extern "C" function we come
// across.
if (getLangOpts().CXXExceptions && getLangOpts().ExternCNoUnwind &&
    FD->isExternC() && !FD->hasAttr<NoThrowAttr>()) {
  const auto *FPT = FD->getType()->getAs<FunctionProtoType>();
  if (!FPT || FPT->getExceptionSpecType() == EST_None)
    FD->addAttr(NoThrowAttr::CreateImplicit(Context, FD->getLocation()));
}

IdentifierInfo *Name = FD->getIdentifier();
if (!Name)
  return;
if ((!getLangOpts().CPlusPlus &&
     FD->getDeclContext()->isTranslationUnit()) ||
    (isa<LinkageSpecDecl>(FD->getDeclContext()) &&
     cast<LinkageSpecDecl>(FD->getDeclContext())->getLanguage() ==
     LinkageSpecDecl::lang_c)) {
  // Okay: this could be a libc/libm/Objective-C function we know
  // about.
} else
  return;

if (Name->isStr("asprintf") || Name->isStr("vasprintf")) {
  // FIXME: asprintf and vasprintf aren't C99 functions. Should they be
  // target-specific builtins, perhaps?
  if (!FD->hasAttr<FormatAttr>())
    FD->addAttr(FormatAttr::CreateImplicit(Context,
                                           &Context.Idents.get("printf"), 2,
                                           Name->isStr("vasprintf") ? 0 : 3,
                                           FD->getLocation()));
}

if (Name->isStr("__CFStringMakeConstantString")) {
  // We already have a __builtin___CFStringMakeConstantString,
  // but builds that use -fno-constant-cfstrings don't go through that.
  if (!FD->hasAttr<FormatArgAttr>())
    FD->addAttr(FormatArgAttr::CreateImplicit(Context, ParamIdx(1, FD),
                                              FD->getLocation()));
}
15179}

15181TypedefDecl *Sema::ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
                                  TypeSourceInfo *TInfo) {
assert(D.getIdentifier() && "Wrong callback for declspec without declarator")((void)0);
assert(!T.isNull() && "GetTypeForDeclarator() returned null type")((void)0);

if (!TInfo) {
  assert(D.isInvalidType() && "no declarator info for valid type")((void)0);
  TInfo = Context.getTrivialTypeSourceInfo(T);
}

// Scope manipulation handled by caller.
TypedefDecl *NewTD =
    TypedefDecl::Create(Context, CurContext, D.getBeginLoc(),
                        D.getIdentifierLoc(), D.getIdentifier(), TInfo);

// Bail out immediately if we have an invalid declaration.
if (D.isInvalidType()) {
  NewTD->setInvalidDecl();
  return NewTD;
}

if (D.getDeclSpec().isModulePrivateSpecified()) {
  if (CurContext->isFunctionOrMethod())
    Diag(NewTD->getLocation(), diag::err_module_private_local)
        << 2 << NewTD
        << SourceRange(D.getDeclSpec().getModulePrivateSpecLoc())
        << FixItHint::CreateRemoval(
               D.getDeclSpec().getModulePrivateSpecLoc());
  else
    NewTD->setModulePrivate();
}

// C++ [dcl.typedef]p8:
//   If the typedef declaration defines an unnamed class (or
//   enum), the first typedef-name declared by the declaration
//   to be that class type (or enum type) is used to denote the
//   class type (or enum type) for linkage purposes only.
// We need to check whether the type was declared in the declaration.
switch (D.getDeclSpec().getTypeSpecType()) {
case TST_enum:
case TST_struct:
case TST_interface:
case TST_union:
case TST_class: {
  TagDecl *tagFromDeclSpec = cast<TagDecl>(D.getDeclSpec().getRepAsDecl());
  setTagNameForLinkagePurposes(tagFromDeclSpec, NewTD);
  break;
}

default:
  break;
}

return NewTD;
15235}

15237/// Check that this is a valid underlying type for an enum declaration.
15238bool Sema::CheckEnumUnderlyingType(TypeSourceInfo *TI) {
SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();
QualType T = TI->getType();

if (T->isDependentType())
  return false;

// This doesn't use 'isIntegralType' despite the error message mentioning
// integral type because isIntegralType would also allow enum types in C.
if (const BuiltinType *BT = T->getAs<BuiltinType>())
  if (BT->isInteger())
    return false;

if (T->isExtIntType())
  return false;

return Diag(UnderlyingLoc, diag::err_enum_invalid_underlying) << T;
15255}

15257/// Check whether this is a valid redeclaration of a previous enumeration.
15258/// \return true if the redeclaration was invalid.
15259bool Sema::CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
                                QualType EnumUnderlyingTy, bool IsFixed,
                                const EnumDecl *Prev) {
if (IsScoped != Prev->isScoped()) {
  Diag(EnumLoc, diag::err_enum_redeclare_scoped_mismatch)
    << Prev->isScoped();
  Diag(Prev->getLocation(), diag::note_previous_declaration);
  return true;
}

if (IsFixed && Prev->isFixed()) {
  if (!EnumUnderlyingTy->isDependentType() &&
      !Prev->getIntegerType()->isDependentType() &&
      !Context.hasSameUnqualifiedType(EnumUnderlyingTy,
                                      Prev->getIntegerType())) {
    // TODO: Highlight the underlying type of the redeclaration.
    Diag(EnumLoc, diag::err_enum_redeclare_type_mismatch)
      << EnumUnderlyingTy << Prev->getIntegerType();
    Diag(Prev->getLocation(), diag::note_previous_declaration)
        << Prev->getIntegerTypeRange();
    return true;
  }
} else if (IsFixed != Prev->isFixed()) {
  Diag(EnumLoc, diag::err_enum_redeclare_fixed_mismatch)
    << Prev->isFixed();
  Diag(Prev->getLocation(), diag::note_previous_declaration);
  return true;
}

return false;
15289}

15291/// Get diagnostic %select index for tag kind for
15292/// redeclaration diagnostic message.
15293/// WARNING: Indexes apply to particular diagnostics only!
15294///
15295/// \returns diagnostic %select index.
15296static unsigned getRedeclDiagFromTagKind(TagTypeKind Tag) {
switch (Tag) {
case TTK_Struct: return 0;
case TTK_Interface: return 1;
case TTK_Class:  return 2;
default: llvm_unreachable("Invalid tag kind for redecl diagnostic!")__builtin_unreachable();
}
15303}

15305/// Determine if tag kind is a class-key compatible with
15306/// class for redeclaration (class, struct, or __interface).
15307///
15308/// \returns true iff the tag kind is compatible.
15309static bool isClassCompatTagKind(TagTypeKind Tag)
15310{
return Tag == TTK_Struct || Tag == TTK_Class || Tag == TTK_Interface;
15312}

15314Sema::NonTagKind Sema::getNonTagTypeDeclKind(const Decl *PrevDecl,
                                           TagTypeKind TTK) {
if (isa<TypedefDecl>(PrevDecl))
  return NTK_Typedef;
else if (isa<TypeAliasDecl>(PrevDecl))
  return NTK_TypeAlias;
else if (isa<ClassTemplateDecl>(PrevDecl))
  return NTK_Template;
else if (isa<TypeAliasTemplateDecl>(PrevDecl))
  return NTK_TypeAliasTemplate;
else if (isa<TemplateTemplateParmDecl>(PrevDecl))
  return NTK_TemplateTemplateArgument;
switch (TTK) {
case TTK_Struct:
case TTK_Interface:
case TTK_Class:
  return getLangOpts().CPlusPlus ? NTK_NonClass : NTK_NonStruct;
case TTK_Union:
  return NTK_NonUnion;
case TTK_Enum:
  return NTK_NonEnum;
}
llvm_unreachable("invalid TTK")__builtin_unreachable();
15337}

15339/// Determine whether a tag with a given kind is acceptable
15340/// as a redeclaration of the given tag declaration.
15341///
15342/// \returns true if the new tag kind is acceptable, false otherwise.
15343bool Sema::isAcceptableTagRedeclaration(const TagDecl *Previous,
                                      TagTypeKind NewTag, bool isDefinition,
                                      SourceLocation NewTagLoc,
                                      const IdentifierInfo *Name) {
// C++ [dcl.type.elab]p3:
//   The class-key or enum keyword present in the
//   elaborated-type-specifier shall agree in kind with the
//   declaration to which the name in the elaborated-type-specifier
//   refers. This rule also applies to the form of
//   elaborated-type-specifier that declares a class-name or
//   friend class since it can be construed as referring to the
//   definition of the class. Thus, in any
//   elaborated-type-specifier, the enum keyword shall be used to
//   refer to an enumeration (7.2), the union class-key shall be
//   used to refer to a union (clause 9), and either the class or
//   struct class-key shall be used to refer to a class (clause 9)
//   declared using the class or struct class-key.
TagTypeKind OldTag = Previous->getTagKind();
if (OldTag != NewTag &&
    !(isClassCompatTagKind(OldTag) && isClassCompatTagKind(NewTag)))
  return false;

// Tags are compatible, but we might still want to warn on mismatched tags.
// Non-class tags can't be mismatched at this point.
if (!isClassCompatTagKind(NewTag))
  return true;

// Declarations for which -Wmismatched-tags is disabled are entirely ignored
// by our warning analysis. We don't want to warn about mismatches with (eg)
// declarations in system headers that are designed to be specialized, but if
// a user asks us to warn, we should warn if their code contains mismatched
// declarations.
auto IsIgnoredLoc = [&](SourceLocation Loc) {
  return getDiagnostics().isIgnored(diag::warn_struct_class_tag_mismatch,
                                    Loc);
};
if (IsIgnoredLoc(NewTagLoc))
  return true;

auto IsIgnored = [&](const TagDecl *Tag) {
  return IsIgnoredLoc(Tag->getLocation());
};
while (IsIgnored(Previous)) {
  Previous = Previous->getPreviousDecl();
  if (!Previous)
    return true;
  OldTag = Previous->getTagKind();
}

bool isTemplate = false;
if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Previous))
  isTemplate = Record->getDescribedClassTemplate();

if (inTemplateInstantiation()) {
  if (OldTag != NewTag) {
    // In a template instantiation, do not offer fix-its for tag mismatches
    // since they usually mess up the template instead of fixing the problem.
    Diag(NewTagLoc, diag::warn_struct_class_tag_mismatch)
      << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
      << getRedeclDiagFromTagKind(OldTag);
    // FIXME: Note previous location?
  }
  return true;
}

if (isDefinition) {
  // On definitions, check all previous tags and issue a fix-it for each
  // one that doesn't match the current tag.
  if (Previous->getDefinition()) {
    // Don't suggest fix-its for redefinitions.
    return true;
  }

  bool previousMismatch = false;
  for (const TagDecl *I : Previous->redecls()) {
    if (I->getTagKind() != NewTag) {
      // Ignore previous declarations for which the warning was disabled.
      if (IsIgnored(I))
        continue;

      if (!previousMismatch) {
        previousMismatch = true;
        Diag(NewTagLoc, diag::warn_struct_class_previous_tag_mismatch)
          << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
          << getRedeclDiagFromTagKind(I->getTagKind());
      }
      Diag(I->getInnerLocStart(), diag::note_struct_class_suggestion)
        << getRedeclDiagFromTagKind(NewTag)
        << FixItHint::CreateReplacement(I->getInnerLocStart(),
             TypeWithKeyword::getTagTypeKindName(NewTag));
    }
  }
  return true;
}

// Identify the prevailing tag kind: this is the kind of the definition (if
// there is a non-ignored definition), or otherwise the kind of the prior
// (non-ignored) declaration.
const TagDecl *PrevDef = Previous->getDefinition();
if (PrevDef && IsIgnored(PrevDef))
  PrevDef = nullptr;
const TagDecl *Redecl = PrevDef ? PrevDef : Previous;
if (Redecl->getTagKind() != NewTag) {
  Diag(NewTagLoc, diag::warn_struct_class_tag_mismatch)
    << getRedeclDiagFromTagKind(NewTag) << isTemplate << Name
    << getRedeclDiagFromTagKind(OldTag);
  Diag(Redecl->getLocation(), diag::note_previous_use);

  // If there is a previous definition, suggest a fix-it.
  if (PrevDef) {
    Diag(NewTagLoc, diag::note_struct_class_suggestion)
      << getRedeclDiagFromTagKind(Redecl->getTagKind())
      << FixItHint::CreateReplacement(SourceRange(NewTagLoc),
           TypeWithKeyword::getTagTypeKindName(Redecl->getTagKind()));
  }
}

return true;
15461}

15463/// Add a minimal nested name specifier fixit hint to allow lookup of a tag name
15464/// from an outer enclosing namespace or file scope inside a friend declaration.
15465/// This should provide the commented out code in the following snippet:
15466///   namespace N {
15467///     struct X;
15468///     namespace M {
15469///       struct Y { friend struct /*N::*/ X; };
15470///     }
15471///   }
15472static FixItHint createFriendTagNNSFixIt(Sema &SemaRef, NamedDecl *ND, Scope *S,
                                       SourceLocation NameLoc) {
// While the decl is in a namespace, do repeated lookup of that name and see
// if we get the same namespace back.  If we do not, continue until
// translation unit scope, at which point we have a fully qualified NNS.
SmallVector<IdentifierInfo *, 4> Namespaces;
DeclContext *DC = ND->getDeclContext()->getRedeclContext();
for (; !DC->isTranslationUnit(); DC = DC->getParent()) {
  // This tag should be declared in a namespace, which can only be enclosed by
  // other namespaces.  Bail if there's an anonymous namespace in the chain.
  NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(DC);
  if (!Namespace || Namespace->isAnonymousNamespace())
    return FixItHint();
  IdentifierInfo *II = Namespace->getIdentifier();
  Namespaces.push_back(II);
  NamedDecl *Lookup = SemaRef.LookupSingleName(
      S, II, NameLoc, Sema::LookupNestedNameSpecifierName);
  if (Lookup == Namespace)
    break;
}

// Once we have all the namespaces, reverse them to go outermost first, and
// build an NNS.
SmallString<64> Insertion;
llvm::raw_svector_ostream OS(Insertion);
if (DC->isTranslationUnit())
  OS << "::";
std::reverse(Namespaces.begin(), Namespaces.end());
for (auto *II : Namespaces)
  OS << II->getName() << "::";
return FixItHint::CreateInsertion(NameLoc, Insertion);
15503}

15505/// Determine whether a tag originally declared in context \p OldDC can
15506/// be redeclared with an unqualified name in \p NewDC (assuming name lookup
15507/// found a declaration in \p OldDC as a previous decl, perhaps through a
15508/// using-declaration).
15509static bool isAcceptableTagRedeclContext(Sema &S, DeclContext *OldDC,
                                       DeclContext *NewDC) {
OldDC = OldDC->getRedeclContext();
NewDC = NewDC->getRedeclContext();

if (OldDC->Equals(NewDC))
  return true;

// In MSVC mode, we allow a redeclaration if the contexts are related (either
// encloses the other).
if (S.getLangOpts().MSVCCompat &&
    (OldDC->Encloses(NewDC) || NewDC->Encloses(OldDC)))
  return true;

return false;
15524}

15526/// This is invoked when we see 'struct foo' or 'struct {'.  In the
15527/// former case, Name will be non-null.  In the later case, Name will be null.
15528/// TagSpec indicates what kind of tag this is. TUK indicates whether this is a
15529/// reference/declaration/definition of a tag.
15530///
15531/// \param IsTypeSpecifier \c true if this is a type-specifier (or
15532/// trailing-type-specifier) other than one in an alias-declaration.
15533///
15534/// \param SkipBody If non-null, will be set to indicate if the caller should
15535/// skip the definition of this tag and treat it as if it were a declaration.
15536Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                   SourceLocation KWLoc, CXXScopeSpec &SS,
                   IdentifierInfo *Name, SourceLocation NameLoc,
                   const ParsedAttributesView &Attrs, AccessSpecifier AS,
                   SourceLocation ModulePrivateLoc,
                   MultiTemplateParamsArg TemplateParameterLists,
                   bool &OwnedDecl, bool &IsDependent,
                   SourceLocation ScopedEnumKWLoc,
                   bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
                   bool IsTypeSpecifier, bool IsTemplateParamOrArg,
                   SkipBodyInfo *SkipBody) {
// If this is not a definition, it must have a name.
IdentifierInfo *OrigName = Name;
assert((Name != nullptr || TUK == TUK_Definition) &&((void)0)
       "Nameless record must be a definition!")((void)0);
assert(TemplateParameterLists.size() == 0 || TUK != TUK_Reference)((void)0);

OwnedDecl = false;
TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
bool ScopedEnum = ScopedEnumKWLoc.isValid();

// FIXME: Check member specializations more carefully.
bool isMemberSpecialization = false;
bool Invalid = false;

// We only need to do this matching if we have template parameters
// or a scope specifier, which also conveniently avoids this work
// for non-C++ cases.
if (TemplateParameterLists.size() > 0 ||
    (SS.isNotEmpty() && TUK != TUK_Reference)) {
  if (TemplateParameterList *TemplateParams =
          MatchTemplateParametersToScopeSpecifier(
              KWLoc, NameLoc, SS, nullptr, TemplateParameterLists,
              TUK == TUK_Friend, isMemberSpecialization, Invalid)) {
    if (Kind == TTK_Enum) {
      Diag(KWLoc, diag::err_enum_template);
      return nullptr;
    }

    if (TemplateParams->size() > 0) {
      // This is a declaration or definition of a class template (which may
      // be a member of another template).

      if (Invalid)
        return nullptr;

      OwnedDecl = false;
      DeclResult Result = CheckClassTemplate(
          S, TagSpec, TUK, KWLoc, SS, Name, NameLoc, Attrs, TemplateParams,
          AS, ModulePrivateLoc,
          /*FriendLoc*/ SourceLocation(), TemplateParameterLists.size() - 1,
          TemplateParameterLists.data(), SkipBody);
      return Result.get();
    } else {
      // The "template<>" header is extraneous.
      Diag(TemplateParams->getTemplateLoc(), diag::err_template_tag_noparams)
        << TypeWithKeyword::getTagTypeKindName(Kind) << Name;
      isMemberSpecialization = true;
    }
  }

  if (!TemplateParameterLists.empty() && isMemberSpecialization &&
      CheckTemplateDeclScope(S, TemplateParameterLists.back()))
    return nullptr;
}

// Figure out the underlying type if this a enum declaration. We need to do
// this early, because it's needed to detect if this is an incompatible
// redeclaration.
llvm::PointerUnion<const Type*, TypeSourceInfo*> EnumUnderlying;
bool IsFixed = !UnderlyingType.isUnset() || ScopedEnum;

if (Kind == TTK_Enum) {
  if (UnderlyingType.isInvalid() || (!UnderlyingType.get() && ScopedEnum)) {
    // No underlying type explicitly specified, or we failed to parse the
    // type, default to int.
    EnumUnderlying = Context.IntTy.getTypePtr();
  } else if (UnderlyingType.get()) {
    // C++0x 7.2p2: The type-specifier-seq of an enum-base shall name an
    // integral type; any cv-qualification is ignored.
    TypeSourceInfo *TI = nullptr;
    GetTypeFromParser(UnderlyingType.get(), &TI);
    EnumUnderlying = TI;

    if (CheckEnumUnderlyingType(TI))
      // Recover by falling back to int.
      EnumUnderlying = Context.IntTy.getTypePtr();

    if (DiagnoseUnexpandedParameterPack(TI->getTypeLoc().getBeginLoc(), TI,
                                        UPPC_FixedUnderlyingType))
      EnumUnderlying = Context.IntTy.getTypePtr();

  } else if (Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment()) {
    // For MSVC ABI compatibility, unfixed enums must use an underlying type
    // of 'int'. However, if this is an unfixed forward declaration, don't set
    // the underlying type unless the user enables -fms-compatibility. This
    // makes unfixed forward declared enums incomplete and is more conforming.
    if (TUK == TUK_Definition || getLangOpts().MSVCCompat)
      EnumUnderlying = Context.IntTy.getTypePtr();
  }
}

DeclContext *SearchDC = CurContext;
DeclContext *DC = CurContext;
bool isStdBadAlloc = false;
bool isStdAlignValT = false;

RedeclarationKind Redecl = forRedeclarationInCurContext();
if (TUK == TUK_Friend || TUK == TUK_Reference)
  Redecl = NotForRedeclaration;

/// Create a new tag decl in C/ObjC. Since the ODR-like semantics for ObjC/C
/// implemented asks for structural equivalence checking, the returned decl
/// here is passed back to the parser, allowing the tag body to be parsed.
auto createTagFromNewDecl = [&]() -> TagDecl * {
  assert(!getLangOpts().CPlusPlus && "not meant for C++ usage")((void)0);
  // If there is an identifier, use the location of the identifier as the
  // location of the decl, otherwise use the location of the struct/union
  // keyword.
  SourceLocation Loc = NameLoc.isValid() ? NameLoc : KWLoc;
  TagDecl *New = nullptr;

  if (Kind == TTK_Enum) {
    New = EnumDecl::Create(Context, SearchDC, KWLoc, Loc, Name, nullptr,
                           ScopedEnum, ScopedEnumUsesClassTag, IsFixed);
    // If this is an undefined enum, bail.
    if (TUK != TUK_Definition && !Invalid)
      return nullptr;
    if (EnumUnderlying) {
      EnumDecl *ED = cast<EnumDecl>(New);
      if (TypeSourceInfo *TI = EnumUnderlying.dyn_cast<TypeSourceInfo *>())
        ED->setIntegerTypeSourceInfo(TI);
      else
        ED->setIntegerType(QualType(EnumUnderlying.get<const Type *>(), 0));
      ED->setPromotionType(ED->getIntegerType());
    }
  } else { // struct/union
    New = RecordDecl::Create(Context, Kind, SearchDC, KWLoc, Loc, Name,
                             nullptr);
  }

  if (RecordDecl *RD = dyn_cast<RecordDecl>(New)) {
    // Add alignment attributes if necessary; these attributes are checked
    // when the ASTContext lays out the structure.
    //
    // It is important for implementing the correct semantics that this
    // happen here (in ActOnTag). The #pragma pack stack is
    // maintained as a result of parser callbacks which can occur at
    // many points during the parsing of a struct declaration (because
    // the #pragma tokens are effectively skipped over during the
    // parsing of the struct).
    if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
      AddAlignmentAttributesForRecord(RD);
      AddMsStructLayoutForRecord(RD);
    }
  }
  New->setLexicalDeclContext(CurContext);
  return New;
};

LookupResult Previous(*this, Name, NameLoc, LookupTagName, Redecl);
if (Name && SS.isNotEmpty()) {
  // We have a nested-name tag ('struct foo::bar').

  // Check for invalid 'foo::'.
  if (SS.isInvalid()) {
    Name = nullptr;
    goto CreateNewDecl;
  }

  // If this is a friend or a reference to a class in a dependent
  // context, don't try to make a decl for it.
  if (TUK == TUK_Friend || TUK == TUK_Reference) {
    DC = computeDeclContext(SS, false);
    if (!DC) {
      IsDependent = true;
      return nullptr;
    }
  } else {
    DC = computeDeclContext(SS, true);
    if (!DC) {
      Diag(SS.getRange().getBegin(), diag::err_dependent_nested_name_spec)
        << SS.getRange();
      return nullptr;
    }
  }

  if (RequireCompleteDeclContext(SS, DC))
    return nullptr;

  SearchDC = DC;
  // Look-up name inside 'foo::'.
  LookupQualifiedName(Previous, DC);

  if (Previous.isAmbiguous())
    return nullptr;

  if (Previous.empty()) {
    // Name lookup did not find anything. However, if the
    // nested-name-specifier refers to the current instantiation,
    // and that current instantiation has any dependent base
    // classes, we might find something at instantiation time: treat
    // this as a dependent elaborated-type-specifier.
    // But this only makes any sense for reference-like lookups.
    if (Previous.wasNotFoundInCurrentInstantiation() &&
        (TUK == TUK_Reference || TUK == TUK_Friend)) {
      IsDependent = true;
      return nullptr;
    }

    // A tag 'foo::bar' must already exist.
    Diag(NameLoc, diag::err_not_tag_in_scope)
      << Kind << Name << DC << SS.getRange();
    Name = nullptr;
    Invalid = true;
    goto CreateNewDecl;
  }
} else if (Name) {
  // C++14 [class.mem]p14:
  //   If T is the name of a class, then each of the following shall have a
  //   name different from T:
  //    -- every member of class T that is itself a type
  if (TUK != TUK_Reference && TUK != TUK_Friend &&
      DiagnoseClassNameShadow(SearchDC, DeclarationNameInfo(Name, NameLoc)))
    return nullptr;

  // If this is a named struct, check to see if there was a previous forward
  // declaration or definition.
  // FIXME: We're looking into outer scopes here, even when we
  // shouldn't be. Doing so can result in ambiguities that we
  // shouldn't be diagnosing.
  LookupName(Previous, S);

  // When declaring or defining a tag, ignore ambiguities introduced
  // by types using'ed into this scope.
  if (Previous.isAmbiguous() &&
      (TUK == TUK_Definition || TUK == TUK_Declaration)) {
    LookupResult::Filter F = Previous.makeFilter();
    while (F.hasNext()) {
      NamedDecl *ND = F.next();
      if (!ND->getDeclContext()->getRedeclContext()->Equals(
              SearchDC->getRedeclContext()))
        F.erase();
    }
    F.done();
  }

  // C++11 [namespace.memdef]p3:
  //   If the name in a friend declaration is neither qualified nor
  //   a template-id and the declaration is a function or an
  //   elaborated-type-specifier, the lookup to determine whether
  //   the entity has been previously declared shall not consider
  //   any scopes outside the innermost enclosing namespace.
  //
  // MSVC doesn't implement the above rule for types, so a friend tag
  // declaration may be a redeclaration of a type declared in an enclosing
  // scope.  They do implement this rule for friend functions.
  //
  // Does it matter that this should be by scope instead of by
  // semantic context?
  if (!Previous.empty() && TUK == TUK_Friend) {
    DeclContext *EnclosingNS = SearchDC->getEnclosingNamespaceContext();
    LookupResult::Filter F = Previous.makeFilter();
    bool FriendSawTagOutsideEnclosingNamespace = false;
    while (F.hasNext()) {
      NamedDecl *ND = F.next();
      DeclContext *DC = ND->getDeclContext()->getRedeclContext();
      if (DC->isFileContext() &&
          !EnclosingNS->Encloses(ND->getDeclContext())) {
        if (getLangOpts().MSVCCompat)
          FriendSawTagOutsideEnclosingNamespace = true;
        else
          F.erase();
      }
    }
    F.done();

    // Diagnose this MSVC extension in the easy case where lookup would have
    // unambiguously found something outside the enclosing namespace.
    if (Previous.isSingleResult() && FriendSawTagOutsideEnclosingNamespace) {
      NamedDecl *ND = Previous.getFoundDecl();
      Diag(NameLoc, diag::ext_friend_tag_redecl_outside_namespace)
          << createFriendTagNNSFixIt(*this, ND, S, NameLoc);
    }
  }

  // Note:  there used to be some attempt at recovery here.
  if (Previous.isAmbiguous())
    return nullptr;

  if (!getLangOpts().CPlusPlus && TUK != TUK_Reference) {
    // FIXME: This makes sure that we ignore the contexts associated
    // with C structs, unions, and enums when looking for a matching
    // tag declaration or definition. See the similar lookup tweak
    // in Sema::LookupName; is there a better way to deal with this?
    while (isa<RecordDecl>(SearchDC) || isa<EnumDecl>(SearchDC))
      SearchDC = SearchDC->getParent();
  }
}

if (Previous.isSingleResult() &&
    Previous.getFoundDecl()->isTemplateParameter()) {
  // Maybe we will complain about the shadowed template parameter.
  DiagnoseTemplateParameterShadow(NameLoc, Previous.getFoundDecl());
  // Just pretend that we didn't see the previous declaration.
  Previous.clear();
}

if (getLangOpts().CPlusPlus && Name && DC && StdNamespace &&
    DC->Equals(getStdNamespace())) {
  if (Name->isStr("bad_alloc")) {
    // This is a declaration of or a reference to "std::bad_alloc".
    isStdBadAlloc = true;

    // If std::bad_alloc has been implicitly declared (but made invisible to
    // name lookup), fill in this implicit declaration as the previous
    // declaration, so that the declarations get chained appropriately.
    if (Previous.empty() && StdBadAlloc)
      Previous.addDecl(getStdBadAlloc());
  } else if (Name->isStr("align_val_t")) {
    isStdAlignValT = true;
    if (Previous.empty() && StdAlignValT)
      Previous.addDecl(getStdAlignValT());
  }
}

// If we didn't find a previous declaration, and this is a reference
// (or friend reference), move to the correct scope.  In C++, we
// also need to do a redeclaration lookup there, just in case
// there's a shadow friend decl.
if (Name && Previous.empty() &&
    (TUK == TUK_Reference || TUK == TUK_Friend || IsTemplateParamOrArg)) {
  if (Invalid) goto CreateNewDecl;
  assert(SS.isEmpty())((void)0);

  if (TUK == TUK_Reference || IsTemplateParamOrArg) {
    // C++ [basic.scope.pdecl]p5:
    //   -- for an elaborated-type-specifier of the form
    //
    //          class-key identifier
    //
    //      if the elaborated-type-specifier is used in the
    //      decl-specifier-seq or parameter-declaration-clause of a
    //      function defined in namespace scope, the identifier is
    //      declared as a class-name in the namespace that contains
    //      the declaration; otherwise, except as a friend
    //      declaration, the identifier is declared in the smallest
    //      non-class, non-function-prototype scope that contains the
    //      declaration.
    //
    // C99 6.7.2.3p8 has a similar (but not identical!) provision for
    // C structs and unions.
    //
    // It is an error in C++ to declare (rather than define) an enum
    // type, including via an elaborated type specifier.  We'll
    // diagnose that later; for now, declare the enum in the same
    // scope as we would have picked for any other tag type.
    //
    // GNU C also supports this behavior as part of its incomplete
    // enum types extension, while GNU C++ does not.
    //
    // Find the context where we'll be declaring the tag.
    // FIXME: We would like to maintain the current DeclContext as the
    // lexical context,
    SearchDC = getTagInjectionContext(SearchDC);

    // Find the scope where we'll be declaring the tag.
    S = getTagInjectionScope(S, getLangOpts());
  } else {
    assert(TUK == TUK_Friend)((void)0);
    // C++ [namespace.memdef]p3:
    //   If a friend declaration in a non-local class first declares a
    //   class or function, the friend class or function is a member of
    //   the innermost enclosing namespace.
    SearchDC = SearchDC->getEnclosingNamespaceContext();
  }

  // In C++, we need to do a redeclaration lookup to properly
  // diagnose some problems.
  // FIXME: redeclaration lookup is also used (with and without C++) to find a
  // hidden declaration so that we don't get ambiguity errors when using a
  // type declared by an elaborated-type-specifier.  In C that is not correct
  // and we should instead merge compatible types found by lookup.
  if (getLangOpts().CPlusPlus) {
    // FIXME: This can perform qualified lookups into function contexts,
    // which are meaningless.
    Previous.setRedeclarationKind(forRedeclarationInCurContext());
    LookupQualifiedName(Previous, SearchDC);
  } else {
    Previous.setRedeclarationKind(forRedeclarationInCurContext());
    LookupName(Previous, S);
  }
}

// If we have a known previous declaration to use, then use it.
if (Previous.empty() && SkipBody && SkipBody->Previous)
  Previous.addDecl(SkipBody->Previous);

if (!Previous.empty()) {
  NamedDecl *PrevDecl = Previous.getFoundDecl();
  NamedDecl *DirectPrevDecl = Previous.getRepresentativeDecl();

  // It's okay to have a tag decl in the same scope as a typedef
  // which hides a tag decl in the same scope.  Finding this
  // insanity with a redeclaration lookup can only actually happen
  // in C++.
  //
  // This is also okay for elaborated-type-specifiers, which is
  // technically forbidden by the current standard but which is
  // okay according to the likely resolution of an open issue;
  // see http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#407
  if (getLangOpts().CPlusPlus) {
    if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(PrevDecl)) {
      if (const TagType *TT = TD->getUnderlyingType()->getAs<TagType>()) {
        TagDecl *Tag = TT->getDecl();
        if (Tag->getDeclName() == Name &&
            Tag->getDeclContext()->getRedeclContext()
                        ->Equals(TD->getDeclContext()->getRedeclContext())) {
          PrevDecl = Tag;
          Previous.clear();
          Previous.addDecl(Tag);
          Previous.resolveKind();
        }
      }
    }
  }

  // If this is a redeclaration of a using shadow declaration, it must
  // declare a tag in the same context. In MSVC mode, we allow a
  // redefinition if either context is within the other.
  if (auto *Shadow = dyn_cast<UsingShadowDecl>(DirectPrevDecl)) {
    auto *OldTag = dyn_cast<TagDecl>(PrevDecl);
    if (SS.isEmpty() && TUK != TUK_Reference && TUK != TUK_Friend &&
        isDeclInScope(Shadow, SearchDC, S, isMemberSpecialization) &&
        !(OldTag && isAcceptableTagRedeclContext(
                        *this, OldTag->getDeclContext(), SearchDC))) {
      Diag(KWLoc, diag::err_using_decl_conflict_reverse);
      Diag(Shadow->getTargetDecl()->getLocation(),
           diag::note_using_decl_target);
      Diag(Shadow->getIntroducer()->getLocation(), diag::note_using_decl)
          << 0;
      // Recover by ignoring the old declaration.
      Previous.clear();
      goto CreateNewDecl;
    }
  }

  if (TagDecl *PrevTagDecl = dyn_cast<TagDecl>(PrevDecl)) {
    // If this is a use of a previous tag, or if the tag is already declared
    // in the same scope (so that the definition/declaration completes or
    // rementions the tag), reuse the decl.
    if (TUK == TUK_Reference || TUK == TUK_Friend ||
        isDeclInScope(DirectPrevDecl, SearchDC, S,
                      SS.isNotEmpty() || isMemberSpecialization)) {
      // Make sure that this wasn't declared as an enum and now used as a
      // struct or something similar.
      if (!isAcceptableTagRedeclaration(PrevTagDecl, Kind,
                                        TUK == TUK_Definition, KWLoc,
                                        Name)) {
        bool SafeToContinue
          = (PrevTagDecl->getTagKind() != TTK_Enum &&
             Kind != TTK_Enum);
        if (SafeToContinue)
          Diag(KWLoc, diag::err_use_with_wrong_tag)
            << Name
            << FixItHint::CreateReplacement(SourceRange(KWLoc),
                                            PrevTagDecl->getKindName());
        else
          Diag(KWLoc, diag::err_use_with_wrong_tag) << Name;
        Diag(PrevTagDecl->getLocation(), diag::note_previous_use);

        if (SafeToContinue)
          Kind = PrevTagDecl->getTagKind();
        else {
          // Recover by making this an anonymous redefinition.
          Name = nullptr;
          Previous.clear();
          Invalid = true;
        }
      }

      if (Kind == TTK_Enum && PrevTagDecl->getTagKind() == TTK_Enum) {
        const EnumDecl *PrevEnum = cast<EnumDecl>(PrevTagDecl);
        if (TUK == TUK_Reference || TUK == TUK_Friend)
          return PrevTagDecl;

        QualType EnumUnderlyingTy;
        if (TypeSourceInfo *TI = EnumUnderlying.dyn_cast<TypeSourceInfo*>())
          EnumUnderlyingTy = TI->getType().getUnqualifiedType();
        else if (const Type *T = EnumUnderlying.dyn_cast<const Type*>())
          EnumUnderlyingTy = QualType(T, 0);

        // All conflicts with previous declarations are recovered by
        // returning the previous declaration, unless this is a definition,
        // in which case we want the caller to bail out.
        if (CheckEnumRedeclaration(NameLoc.isValid() ? NameLoc : KWLoc,
                                   ScopedEnum, EnumUnderlyingTy,
                                   IsFixed, PrevEnum))
          return TUK == TUK_Declaration ? PrevTagDecl : nullptr;
      }

      // C++11 [class.mem]p1:
      //   A member shall not be declared twice in the member-specification,
      //   except that a nested class or member class template can be declared
      //   and then later defined.
      if (TUK == TUK_Declaration && PrevDecl->isCXXClassMember() &&
          S->isDeclScope(PrevDecl)) {
        Diag(NameLoc, diag::ext_member_redeclared);
        Diag(PrevTagDecl->getLocation(), diag::note_previous_declaration);
      }

      if (!Invalid) {
        // If this is a use, just return the declaration we found, unless
        // we have attributes.
        if (TUK == TUK_Reference || TUK == TUK_Friend) {
          if (!Attrs.empty()) {
            // FIXME: Diagnose these attributes. For now, we create a new
            // declaration to hold them.
          } else if (TUK == TUK_Reference &&
                     (PrevTagDecl->getFriendObjectKind() ==
                          Decl::FOK_Undeclared ||
                      PrevDecl->getOwningModule() != getCurrentModule()) &&
                     SS.isEmpty()) {
            // This declaration is a reference to an existing entity, but
            // has different visibility from that entity: it either makes
            // a friend visible or it makes a type visible in a new module.
            // In either case, create a new declaration. We only do this if
            // the declaration would have meant the same thing if no prior
            // declaration were found, that is, if it was found in the same
            // scope where we would have injected a declaration.
            if (!getTagInjectionContext(CurContext)->getRedeclContext()
                     ->Equals(PrevDecl->getDeclContext()->getRedeclContext()))
              return PrevTagDecl;
            // This is in the injected scope, create a new declaration in
            // that scope.
            S = getTagInjectionScope(S, getLangOpts());
          } else {
            return PrevTagDecl;
          }
        }

        // Diagnose attempts to redefine a tag.
        if (TUK == TUK_Definition) {
          if (NamedDecl *Def = PrevTagDecl->getDefinition()) {
            // If we're defining a specialization and the previous definition
            // is from an implicit instantiation, don't emit an error
            // here; we'll catch this in the general case below.
            bool IsExplicitSpecializationAfterInstantiation = false;
            if (isMemberSpecialization) {
              if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Def))
                IsExplicitSpecializationAfterInstantiation =
                  RD->getTemplateSpecializationKind() !=
                  TSK_ExplicitSpecialization;
              else if (EnumDecl *ED = dyn_cast<EnumDecl>(Def))
                IsExplicitSpecializationAfterInstantiation =
                  ED->getTemplateSpecializationKind() !=
                  TSK_ExplicitSpecialization;
            }

            // Note that clang allows ODR-like semantics for ObjC/C, i.e., do
            // not keep more that one definition around (merge them). However,
            // ensure the decl passes the structural compatibility check in
            // C11 6.2.7/1 (or 6.1.2.6/1 in C89).
            NamedDecl *Hidden = nullptr;
            if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
              // There is a definition of this tag, but it is not visible. We
              // explicitly make use of C++'s one definition rule here, and
              // assume that this definition is identical to the hidden one
              // we already have. Make the existing definition visible and
              // use it in place of this one.
              if (!getLangOpts().CPlusPlus) {
                // Postpone making the old definition visible until after we
                // complete parsing the new one and do the structural
                // comparison.
                SkipBody->CheckSameAsPrevious = true;
                SkipBody->New = createTagFromNewDecl();
                SkipBody->Previous = Def;
                return Def;
              } else {
                SkipBody->ShouldSkip = true;
                SkipBody->Previous = Def;
                makeMergedDefinitionVisible(Hidden);
                // Carry on and handle it like a normal definition. We'll
                // skip starting the definitiion later.
              }
            } else if (!IsExplicitSpecializationAfterInstantiation) {
              // A redeclaration in function prototype scope in C isn't
              // visible elsewhere, so merely issue a warning.
              if (!getLangOpts().CPlusPlus && S->containedInPrototypeScope())
                Diag(NameLoc, diag::warn_redefinition_in_param_list) << Name;
              else
                Diag(NameLoc, diag::err_redefinition) << Name;
              notePreviousDefinition(Def,
                                     NameLoc.isValid() ? NameLoc : KWLoc);
              // If this is a redefinition, recover by making this
              // struct be anonymous, which will make any later
              // references get the previous definition.
              Name = nullptr;
              Previous.clear();
              Invalid = true;
            }
          } else {
            // If the type is currently being defined, complain
            // about a nested redefinition.
            auto *TD = Context.getTagDeclType(PrevTagDecl)->getAsTagDecl();
            if (TD->isBeingDefined()) {
              Diag(NameLoc, diag::err_nested_redefinition) << Name;
              Diag(PrevTagDecl->getLocation(),
                   diag::note_previous_definition);
              Name = nullptr;
              Previous.clear();
              Invalid = true;
            }
          }

          // Okay, this is definition of a previously declared or referenced
          // tag. We're going to create a new Decl for it.
        }

        // Okay, we're going to make a redeclaration.  If this is some kind
        // of reference, make sure we build the redeclaration in the same DC
        // as the original, and ignore the current access specifier.
        if (TUK == TUK_Friend || TUK == TUK_Reference) {
          SearchDC = PrevTagDecl->getDeclContext();
          AS = AS_none;
        }
      }
      // If we get here we have (another) forward declaration or we
      // have a definition.  Just create a new decl.

    } else {
      // If we get here, this is a definition of a new tag type in a nested
      // scope, e.g. "struct foo; void bar() { struct foo; }", just create a
      // new decl/type.  We set PrevDecl to NULL so that the entities
      // have distinct types.
      Previous.clear();
    }
    // If we get here, we're going to create a new Decl. If PrevDecl
    // is non-NULL, it's a definition of the tag declared by
    // PrevDecl. If it's NULL, we have a new definition.

  // Otherwise, PrevDecl is not a tag, but was found with tag
  // lookup.  This is only actually possible in C++, where a few
  // things like templates still live in the tag namespace.
  } else {
    // Use a better diagnostic if an elaborated-type-specifier
    // found the wrong kind of type on the first
    // (non-redeclaration) lookup.
    if ((TUK == TUK_Reference || TUK == TUK_Friend) &&
        !Previous.isForRedeclaration()) {
      NonTagKind NTK = getNonTagTypeDeclKind(PrevDecl, Kind);
      Diag(NameLoc, diag::err_tag_reference_non_tag) << PrevDecl << NTK
                                                     << Kind;
      Diag(PrevDecl->getLocation(), diag::note_declared_at);
      Invalid = true;

    // Otherwise, only diagnose if the declaration is in scope.
    } else if (!isDeclInScope(DirectPrevDecl, SearchDC, S,
                              SS.isNotEmpty() || isMemberSpecialization)) {
      // do nothing

    // Diagnose implicit declarations introduced by elaborated types.
    } else if (TUK == TUK_Reference || TUK == TUK_Friend) {
      NonTagKind NTK = getNonTagTypeDeclKind(PrevDecl, Kind);
      Diag(NameLoc, diag::err_tag_reference_conflict) << NTK;
      Diag(PrevDecl->getLocation(), diag::note_previous_decl) << PrevDecl;
      Invalid = true;

    // Otherwise it's a declaration.  Call out a particularly common
    // case here.
    } else if (TypedefNameDecl *TND = dyn_cast<TypedefNameDecl>(PrevDecl)) {
      unsigned Kind = 0;
      if (isa<TypeAliasDecl>(PrevDecl)) Kind = 1;
      Diag(NameLoc, diag::err_tag_definition_of_typedef)
        << Name << Kind << TND->getUnderlyingType();
      Diag(PrevDecl->getLocation(), diag::note_previous_decl) << PrevDecl;
      Invalid = true;

    // Otherwise, diagnose.
    } else {
      // The tag name clashes with something else in the target scope,
      // issue an error and recover by making this tag be anonymous.
      Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
      notePreviousDefinition(PrevDecl, NameLoc);
      Name = nullptr;
      Invalid = true;
    }

    // The existing declaration isn't relevant to us; we're in a
    // new scope, so clear out the previous declaration.
    Previous.clear();
  }
}

16230CreateNewDecl:

TagDecl *PrevDecl = nullptr;
if (Previous.isSingleResult())
  PrevDecl = cast<TagDecl>(Previous.getFoundDecl());

// If there is an identifier, use the location of the identifier as the
// location of the decl, otherwise use the location of the struct/union
// keyword.
SourceLocation Loc = NameLoc.isValid() ? NameLoc : KWLoc;

// Otherwise, create a new declaration. If there is a previous
// declaration of the same entity, the two will be linked via
// PrevDecl.
TagDecl *New;

if (Kind == TTK_Enum) {
  // FIXME: Tag decls should be chained to any simultaneous vardecls, e.g.:
  // enum X { A, B, C } D;    D should chain to X.
  New = EnumDecl::Create(Context, SearchDC, KWLoc, Loc, Name,
                         cast_or_null<EnumDecl>(PrevDecl), ScopedEnum,
                         ScopedEnumUsesClassTag, IsFixed);

  if (isStdAlignValT && (!StdAlignValT || getStdAlignValT()->isImplicit()))
    StdAlignValT = cast<EnumDecl>(New);

  // If this is an undefined enum, warn.
  if (TUK != TUK_Definition && !Invalid) {
    TagDecl *Def;
    if (IsFixed && cast<EnumDecl>(New)->isFixed()) {
      // C++0x: 7.2p2: opaque-enum-declaration.
      // Conflicts are diagnosed above. Do nothing.
    }
    else if (PrevDecl && (Def = cast<EnumDecl>(PrevDecl)->getDefinition())) {
      Diag(Loc, diag::ext_forward_ref_enum_def)
        << New;
      Diag(Def->getLocation(), diag::note_previous_definition);
    } else {
      unsigned DiagID = diag::ext_forward_ref_enum;
      if (getLangOpts().MSVCCompat)
        DiagID = diag::ext_ms_forward_ref_enum;
      else if (getLangOpts().CPlusPlus)
        DiagID = diag::err_forward_ref_enum;
      Diag(Loc, DiagID);
    }
  }

  if (EnumUnderlying) {
    EnumDecl *ED = cast<EnumDecl>(New);
    if (TypeSourceInfo *TI = EnumUnderlying.dyn_cast<TypeSourceInfo*>())
      ED->setIntegerTypeSourceInfo(TI);
    else
      ED->setIntegerType(QualType(EnumUnderlying.get<const Type*>(), 0));
    ED->setPromotionType(ED->getIntegerType());
    assert(ED->isComplete() && "enum with type should be complete")((void)0);
  }
} else {
  // struct/union/class

  // FIXME: Tag decls should be chained to any simultaneous vardecls, e.g.:
  // struct X { int A; } D;    D should chain to X.
  if (getLangOpts().CPlusPlus) {
    // FIXME: Look for a way to use RecordDecl for simple structs.
    New = CXXRecordDecl::Create(Context, Kind, SearchDC, KWLoc, Loc, Name,
                                cast_or_null<CXXRecordDecl>(PrevDecl));

    if (isStdBadAlloc && (!StdBadAlloc || getStdBadAlloc()->isImplicit()))
      StdBadAlloc = cast<CXXRecordDecl>(New);
  } else
    New = RecordDecl::Create(Context, Kind, SearchDC, KWLoc, Loc, Name,
                             cast_or_null<RecordDecl>(PrevDecl));
}

// C++11 [dcl.type]p3:
//   A type-specifier-seq shall not define a class or enumeration [...].
if (getLangOpts().CPlusPlus && (IsTypeSpecifier || IsTemplateParamOrArg) &&
    TUK == TUK_Definition) {
  Diag(New->getLocation(), diag::err_type_defined_in_type_specifier)
    << Context.getTagDeclType(New);
  Invalid = true;
}

if (!Invalid && getLangOpts().CPlusPlus && TUK == TUK_Definition &&
    DC->getDeclKind() == Decl::Enum) {
  Diag(New->getLocation(), diag::err_type_defined_in_enum)
    << Context.getTagDeclType(New);
  Invalid = true;
}

// Maybe add qualifier info.
if (SS.isNotEmpty()) {
  if (SS.isSet()) {
    // If this is either a declaration or a definition, check the
    // nested-name-specifier against the current context.
    if ((TUK == TUK_Definition || TUK == TUK_Declaration) &&
        diagnoseQualifiedDeclaration(SS, DC, OrigName, Loc,
                                     isMemberSpecialization))
      Invalid = true;

    New->setQualifierInfo(SS.getWithLocInContext(Context));
    if (TemplateParameterLists.size() > 0) {
      New->setTemplateParameterListsInfo(Context, TemplateParameterLists);
    }
  }
  else
    Invalid = true;
}

if (RecordDecl *RD = dyn_cast<RecordDecl>(New)) {
  // Add alignment attributes if necessary; these attributes are checked when
  // the ASTContext lays out the structure.
  //
  // It is important for implementing the correct semantics that this
  // happen here (in ActOnTag). The #pragma pack stack is
  // maintained as a result of parser callbacks which can occur at
  // many points during the parsing of a struct declaration (because
  // the #pragma tokens are effectively skipped over during the
  // parsing of the struct).
  if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
    AddAlignmentAttributesForRecord(RD);
    AddMsStructLayoutForRecord(RD);
  }
}

if (ModulePrivateLoc.isValid()) {
  if (isMemberSpecialization)
    Diag(New->getLocation(), diag::err_module_private_specialization)
      << 2
      << FixItHint::CreateRemoval(ModulePrivateLoc);
  // __module_private__ does not apply to local classes. However, we only
  // diagnose this as an error when the declaration specifiers are
  // freestanding. Here, we just ignore the __module_private__.
  else if (!SearchDC->isFunctionOrMethod())
    New->setModulePrivate();
}

// If this is a specialization of a member class (of a class template),
// check the specialization.
if (isMemberSpecialization && CheckMemberSpecialization(New, Previous))
  Invalid = true;

// If we're declaring or defining a tag in function prototype scope in C,
// note that this type can only be used within the function and add it to
// the list of decls to inject into the function definition scope.
if ((Name || Kind == TTK_Enum) &&
    getNonFieldDeclScope(S)->isFunctionPrototypeScope()) {
  if (getLangOpts().CPlusPlus) {
    // C++ [dcl.fct]p6:
    //   Types shall not be defined in return or parameter types.
    if (TUK == TUK_Definition && !IsTypeSpecifier) {
      Diag(Loc, diag::err_type_defined_in_param_type)
          << Name;
      Invalid = true;
    }
  } else if (!PrevDecl) {
    Diag(Loc, diag::warn_decl_in_param_list) << Context.getTagDeclType(New);
  }
}

if (Invalid)
  New->setInvalidDecl();

// Set the lexical context. If the tag has a C++ scope specifier, the
// lexical context will be different from the semantic context.
New->setLexicalDeclContext(CurContext);

// Mark this as a friend decl if applicable.
// In Microsoft mode, a friend declaration also acts as a forward
// declaration so we always pass true to setObjectOfFriendDecl to make
// the tag name visible.
if (TUK == TUK_Friend)
  New->setObjectOfFriendDecl(getLangOpts().MSVCCompat);

// Set the access specifier.
if (!Invalid && SearchDC->isRecord())
  SetMemberAccessSpecifier(New, PrevDecl, AS);

if (PrevDecl)
  CheckRedeclarationModuleOwnership(New, PrevDecl);

if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
  New->startDefinition();

ProcessDeclAttributeList(S, New, Attrs);
AddPragmaAttributes(S, New);

// If this has an identifier, add it to the scope stack.
if (TUK == TUK_Friend) {
  // We might be replacing an existing declaration in the lookup tables;
  // if so, borrow its access specifier.
  if (PrevDecl)
    New->setAccess(PrevDecl->getAccess());

  DeclContext *DC = New->getDeclContext()->getRedeclContext();
  DC->makeDeclVisibleInContext(New);
  if (Name) // can be null along some error paths
    if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
      PushOnScopeChains(New, EnclosingScope, /* AddToContext = */ false);
} else if (Name) {
  S = getNonFieldDeclScope(S);
  PushOnScopeChains(New, S, true);
} else {
  CurContext->addDecl(New);
}

// If this is the C FILE type, notify the AST context.
if (IdentifierInfo *II = New->getIdentifier())
  if (!New->isInvalidDecl() &&
      New->getDeclContext()->getRedeclContext()->isTranslationUnit() &&
      II->isStr("FILE"))
    Context.setFILEDecl(New);

if (PrevDecl)
  mergeDeclAttributes(New, PrevDecl);

if (auto *CXXRD = dyn_cast<CXXRecordDecl>(New))
  inferGslOwnerPointerAttribute(CXXRD);

// If there's a #pragma GCC visibility in scope, set the visibility of this
// record.
AddPushedVisibilityAttribute(New);

if (isMemberSpecialization && !New->isInvalidDecl())
  CompleteMemberSpecialization(New, Previous);

OwnedDecl = true;
// In C++, don't return an invalid declaration. We can't recover well from
// the cases where we make the type anonymous.
if (Invalid && getLangOpts().CPlusPlus) {
  if (New->isBeingDefined())
    if (auto RD = dyn_cast<RecordDecl>(New))
      RD->completeDefinition();
  return nullptr;
} else if (SkipBody && SkipBody->ShouldSkip) {
  return SkipBody->Previous;
} else {
  return New;
}
16468}

16470void Sema::ActOnTagStartDefinition(Scope *S, Decl *TagD) {
AdjustDeclIfTemplate(TagD);
TagDecl *Tag = cast<TagDecl>(TagD);

// Enter the tag context.
PushDeclContext(S, Tag);

ActOnDocumentableDecl(TagD);

// If there's a #pragma GCC visibility in scope, set the visibility of this
// record.
AddPushedVisibilityAttribute(Tag);
16482}

16484bool Sema::ActOnDuplicateDefinition(DeclSpec &DS, Decl *Prev,
                                  SkipBodyInfo &SkipBody) {
if (!hasStructuralCompatLayout(Prev, SkipBody.New))
  return false;

// Make the previous decl visible.
makeMergedDefinitionVisible(SkipBody.Previous);
return true;
16492}

16494Decl *Sema::ActOnObjCContainerStartDefinition(Decl *IDecl) {
assert(isa<ObjCContainerDecl>(IDecl) &&((void)0)
       "ActOnObjCContainerStartDefinition - Not ObjCContainerDecl")((void)0);
DeclContext *OCD = cast<DeclContext>(IDecl);
assert(OCD->getLexicalParent() == CurContext &&((void)0)
    "The next DeclContext should be lexically contained in the current one.")((void)0);
CurContext = OCD;
return IDecl;
16502}

16504void Sema::ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagD,
                                         SourceLocation FinalLoc,
                                         bool IsFinalSpelledSealed,
                                         bool IsAbstract,
                                         SourceLocation LBraceLoc) {
AdjustDeclIfTemplate(TagD);
CXXRecordDecl *Record = cast<CXXRecordDecl>(TagD);

FieldCollector->StartClass();

if (!Record->getIdentifier())
  return;

if (IsAbstract)
  Record->markAbstract();

if (FinalLoc.isValid()) {
  Record->addAttr(FinalAttr::Create(
      Context, FinalLoc, AttributeCommonInfo::AS_Keyword,
      static_cast<FinalAttr::Spelling>(IsFinalSpelledSealed)));
}
// C++ [class]p2:
//   [...] The class-name is also inserted into the scope of the
//   class itself; this is known as the injected-class-name. For
//   purposes of access checking, the injected-class-name is treated
//   as if it were a public member name.
CXXRecordDecl *InjectedClassName = CXXRecordDecl::Create(
    Context, Record->getTagKind(), CurContext, Record->getBeginLoc(),
    Record->getLocation(), Record->getIdentifier(),
    /*PrevDecl=*/nullptr,
    /*DelayTypeCreation=*/true);
Context.getTypeDeclType(InjectedClassName, Record);
InjectedClassName->setImplicit();
InjectedClassName->setAccess(AS_public);
if (ClassTemplateDecl *Template = Record->getDescribedClassTemplate())
    InjectedClassName->setDescribedClassTemplate(Template);
PushOnScopeChains(InjectedClassName, S);
assert(InjectedClassName->isInjectedClassName() &&((void)0)
       "Broken injected-class-name")((void)0);
16543}

16545void Sema::ActOnTagFinishDefinition(Scope *S, Decl *TagD,
                                  SourceRange BraceRange) {
AdjustDeclIfTemplate(TagD);
TagDecl *Tag = cast<TagDecl>(TagD);
Tag->setBraceRange(BraceRange);

// Make sure we "complete" the definition even it is invalid.
if (Tag->isBeingDefined()) {
  assert(Tag->isInvalidDecl() && "We should already have completed it")((void)0);
  if (RecordDecl *RD = dyn_cast<RecordDecl>(Tag))
    RD->completeDefinition();
}

if (isa<CXXRecordDecl>(Tag)) {
  FieldCollector->FinishClass();
}

// Exit this scope of this tag's definition.
PopDeclContext();

if (getCurLexicalContext()->isObjCContainer() &&
    Tag->getDeclContext()->isFileContext())
  Tag->setTopLevelDeclInObjCContainer();

// Notify the consumer that we've defined a tag.
if (!Tag->isInvalidDecl())
  Consumer.HandleTagDeclDefinition(Tag);
16572}

16574void Sema::ActOnObjCContainerFinishDefinition() {
// Exit this scope of this interface definition.
PopDeclContext();
16577}

16579void Sema::ActOnObjCTemporaryExitContainerContext(DeclContext *DC) {
assert(DC == CurContext && "Mismatch of container contexts")((void)0);
OriginalLexicalContext = DC;
ActOnObjCContainerFinishDefinition();
16583}

16585void Sema::ActOnObjCReenterContainerContext(DeclContext *DC) {
ActOnObjCContainerStartDefinition(cast<Decl>(DC));
OriginalLexicalContext = nullptr;
16588}

16590void Sema::ActOnTagDefinitionError(Scope *S, Decl *TagD) {
AdjustDeclIfTemplate(TagD);
TagDecl *Tag = cast<TagDecl>(TagD);
Tag->setInvalidDecl();

// Make sure we "complete" the definition even it is invalid.
if (Tag->isBeingDefined()) {
  if (RecordDecl *RD = dyn_cast<RecordDecl>(Tag))
    RD->completeDefinition();
}

// We're undoing ActOnTagStartDefinition here, not
// ActOnStartCXXMemberDeclarations, so we don't have to mess with
// the FieldCollector.

PopDeclContext();
16606}

16608// Note that FieldName may be null for anonymous bitfields.
16609ExprResult Sema::VerifyBitField(SourceLocation FieldLoc,
                              IdentifierInfo *FieldName,
                              QualType FieldTy, bool IsMsStruct,
                              Expr *BitWidth, bool *ZeroWidth) {
assert(BitWidth)((void)0);
if (BitWidth->containsErrors())
  return ExprError();

// Default to true; that shouldn't confuse checks for emptiness
if (ZeroWidth)
  *ZeroWidth = true;

// C99 6.7.2.1p4 - verify the field type.
// C++ 9.6p3: A bit-field shall have integral or enumeration type.
if (!FieldTy->isDependentType() && !FieldTy->isIntegralOrEnumerationType()) {
  // Handle incomplete and sizeless types with a specific error.
  if (RequireCompleteSizedType(FieldLoc, FieldTy,
                               diag::err_field_incomplete_or_sizeless))
    return ExprError();
  if (FieldName)
    return Diag(FieldLoc, diag::err_not_integral_type_bitfield)
      << FieldName << FieldTy << BitWidth->getSourceRange();
  return Diag(FieldLoc, diag::err_not_integral_type_anon_bitfield)
    << FieldTy << BitWidth->getSourceRange();
} else if (DiagnoseUnexpandedParameterPack(const_cast<Expr *>(BitWidth),
                                           UPPC_BitFieldWidth))
  return ExprError();

// If the bit-width is type- or value-dependent, don't try to check
// it now.
if (BitWidth->isValueDependent() || BitWidth->isTypeDependent())
  return BitWidth;

llvm::APSInt Value;
ExprResult ICE = VerifyIntegerConstantExpression(BitWidth, &Value, AllowFold);
if (ICE.isInvalid())
  return ICE;
BitWidth = ICE.get();

if (Value != 0 && ZeroWidth)
  *ZeroWidth = false;

// Zero-width bitfield is ok for anonymous field.
if (Value == 0 && FieldName)
  return Diag(FieldLoc, diag::err_bitfield_has_zero_width) << FieldName;

if (Value.isSigned() && Value.isNegative()) {
  if (FieldName)
    return Diag(FieldLoc, diag::err_bitfield_has_negative_width)
             << FieldName << toString(Value, 10);
  return Diag(FieldLoc, diag::err_anon_bitfield_has_negative_width)
    << toString(Value, 10);
}

// The size of the bit-field must not exceed our maximum permitted object
// size.
if (Value.getActiveBits() > ConstantArrayType::getMaxSizeBits(Context)) {
  return Diag(FieldLoc, diag::err_bitfield_too_wide)
         << !FieldName << FieldName << toString(Value, 10);
}

if (!FieldTy->isDependentType()) {
  uint64_t TypeStorageSize = Context.getTypeSize(FieldTy);
  uint64_t TypeWidth = Context.getIntWidth(FieldTy);
  bool BitfieldIsOverwide = Value.ugt(TypeWidth);

  // Over-wide bitfields are an error in C or when using the MSVC bitfield
  // ABI.
  bool CStdConstraintViolation =
      BitfieldIsOverwide && !getLangOpts().CPlusPlus;
  bool MSBitfieldViolation =
      Value.ugt(TypeStorageSize) &&
      (IsMsStruct || Context.getTargetInfo().getCXXABI().isMicrosoft());
  if (CStdConstraintViolation || MSBitfieldViolation) {
    unsigned DiagWidth =
        CStdConstraintViolation ? TypeWidth : TypeStorageSize;
    return Diag(FieldLoc, diag::err_bitfield_width_exceeds_type_width)
           << (bool)FieldName << FieldName << toString(Value, 10)
           << !CStdConstraintViolation << DiagWidth;
  }

  // Warn on types where the user might conceivably expect to get all
  // specified bits as value bits: that's all integral types other than
  // 'bool'.
  if (BitfieldIsOverwide && !FieldTy->isBooleanType() && FieldName) {
    Diag(FieldLoc, diag::warn_bitfield_width_exceeds_type_width)
        << FieldName << toString(Value, 10)
        << (unsigned)TypeWidth;
  }
}

return BitWidth;
16701}

16703/// ActOnField - Each field of a C struct/union is passed into this in order
16704/// to create a FieldDecl object for it.
16705Decl *Sema::ActOnField(Scope *S, Decl *TagD, SourceLocation DeclStart,
                     Declarator &D, Expr *BitfieldWidth) {
FieldDecl *Res = HandleField(S, cast_or_null<RecordDecl>(TagD),
                             DeclStart, D, static_cast<Expr*>(BitfieldWidth),
                             /*InitStyle=*/ICIS_NoInit, AS_public);
return Res;
16711}

16713/// HandleField - Analyze a field of a C struct or a C++ data member.
16714///
16715FieldDecl *Sema::HandleField(Scope *S, RecordDecl *Record,
                           SourceLocation DeclStart,
                           Declarator &D, Expr *BitWidth,
                           InClassInitStyle InitStyle,
                           AccessSpecifier AS) {
if (D.isDecompositionDeclarator()) {
  const DecompositionDeclarator &Decomp = D.getDecompositionDeclarator();
  Diag(Decomp.getLSquareLoc(), diag::err_decomp_decl_context)
    << Decomp.getSourceRange();
  return nullptr;
}

IdentifierInfo *II = D.getIdentifier();
SourceLocation Loc = DeclStart;
if (II) Loc = D.getIdentifierLoc();

TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
QualType T = TInfo->getType();
if (getLangOpts().CPlusPlus) {
  CheckExtraCXXDefaultArguments(D);

  if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
                                      UPPC_DataMemberType)) {
    D.setInvalidType();
    T = Context.IntTy;
    TInfo = Context.getTrivialTypeSourceInfo(T, Loc);
  }
}

DiagnoseFunctionSpecifiers(D.getDeclSpec());

if (D.getDeclSpec().isInlineSpecified())
  Diag(D.getDeclSpec().getInlineSpecLoc(), diag::err_inline_non_function)
      << getLangOpts().CPlusPlus17;
if (DeclSpec::TSCS TSCS = D.getDeclSpec().getThreadStorageClassSpec())
  Diag(D.getDeclSpec().getThreadStorageClassSpecLoc(),
       diag::err_invalid_thread)
    << DeclSpec::getSpecifierName(TSCS);

// Check to see if this name was declared as a member previously
NamedDecl *PrevDecl = nullptr;
LookupResult Previous(*this, II, Loc, LookupMemberName,
                      ForVisibleRedeclaration);
LookupName(Previous, S);
switch (Previous.getResultKind()) {
  case LookupResult::Found:
  case LookupResult::FoundUnresolvedValue:
    PrevDecl = Previous.getAsSingle<NamedDecl>();
    break;

  case LookupResult::FoundOverloaded:
    PrevDecl = Previous.getRepresentativeDecl();
    break;

  case LookupResult::NotFound:
  case LookupResult::NotFoundInCurrentInstantiation:
  case LookupResult::Ambiguous:
    break;
}
Previous.suppressDiagnostics();

if (PrevDecl && PrevDecl->isTemplateParameter()) {
  // Maybe we will complain about the shadowed template parameter.
  DiagnoseTemplateParameterShadow(D.getIdentifierLoc(), PrevDecl);
  // Just pretend that we didn't see the previous declaration.
  PrevDecl = nullptr;
}

if (PrevDecl && !isDeclInScope(PrevDecl, Record, S))
  PrevDecl = nullptr;

bool Mutable
  = (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_mutable);
SourceLocation TSSL = D.getBeginLoc();
FieldDecl *NewFD
  = CheckFieldDecl(II, T, TInfo, Record, Loc, Mutable, BitWidth, InitStyle,
                   TSSL, AS, PrevDecl, &D);

if (NewFD->isInvalidDecl())
  Record->setInvalidDecl();

if (D.getDeclSpec().isModulePrivateSpecified())
  NewFD->setModulePrivate();

if (NewFD->isInvalidDecl() && PrevDecl) {
  // Don't introduce NewFD into scope; there's already something
  // with the same name in the same scope.
} else if (II) {
  PushOnScopeChains(NewFD, S);
} else
  Record->addDecl(NewFD);

return NewFD;
16808}

16810/// Build a new FieldDecl and check its well-formedness.
16811///
16812/// This routine builds a new FieldDecl given the fields name, type,
16813/// record, etc. \p PrevDecl should refer to any previous declaration
16814/// with the same name and in the same scope as the field to be
16815/// created.
16816///
16817/// \returns a new FieldDecl.
16818///
16819/// \todo The Declarator argument is a hack. It will be removed once
16820FieldDecl *Sema::CheckFieldDecl(DeclarationName Name, QualType T,
                              TypeSourceInfo *TInfo,
                              RecordDecl *Record, SourceLocation Loc,
                              bool Mutable, Expr *BitWidth,
                              InClassInitStyle InitStyle,
                              SourceLocation TSSL,
                              AccessSpecifier AS, NamedDecl *PrevDecl,
                              Declarator *D) {
IdentifierInfo *II = Name.getAsIdentifierInfo();
bool InvalidDecl = false;
if (D) InvalidDecl = D->isInvalidType();

// If we receive a broken type, recover by assuming 'int' and
// marking this declaration as invalid.
if (T.isNull() || T->containsErrors()) {
  InvalidDecl = true;
  T = Context.IntTy;
}

QualType EltTy = Context.getBaseElementType(T);
if (!EltTy->isDependentType() && !EltTy->containsErrors()) {
  if (RequireCompleteSizedType(Loc, EltTy,
                               diag::err_field_incomplete_or_sizeless)) {
    // Fields of incomplete type force their record to be invalid.
    Record->setInvalidDecl();
    InvalidDecl = true;
  } else {
    NamedDecl *Def;
    EltTy->isIncompleteType(&Def);
    if (Def && Def->isInvalidDecl()) {
      Record->setInvalidDecl();
      InvalidDecl = true;
    }
  }
}

// TR 18037 does not allow fields to be declared with address space
if (T.hasAddressSpace() || T->isDependentAddressSpaceType() ||
    T->getBaseElementTypeUnsafe()->isDependentAddressSpaceType()) {
  Diag(Loc, diag::err_field_with_address_space);
  Record->setInvalidDecl();
  InvalidDecl = true;
}

if (LangOpts.OpenCL) {
  // OpenCL v1.2 s6.9b,r & OpenCL v2.0 s6.12.5 - The following types cannot be
  // used as structure or union field: image, sampler, event or block types.
  if (T->isEventT() || T->isImageType() || T->isSamplerT() ||
      T->isBlockPointerType()) {
    Diag(Loc, diag::err_opencl_type_struct_or_union_field) << T;
    Record->setInvalidDecl();
    InvalidDecl = true;
  }
  // OpenCL v1.2 s6.9.c: bitfields are not supported, unless Clang extension
  // is enabled.
  if (BitWidth && !getOpenCLOptions().isAvailableOption(
                      "__cl_clang_bitfields", LangOpts)) {
    Diag(Loc, diag::err_opencl_bitfields);
    InvalidDecl = true;
  }
}

// Anonymous bit-fields cannot be cv-qualified (CWG 2229).
if (!InvalidDecl && getLangOpts().CPlusPlus && !II && BitWidth &&
    T.hasQualifiers()) {
  InvalidDecl = true;
  Diag(Loc, diag::err_anon_bitfield_qualifiers);
}

// C99 6.7.2.1p8: A member of a structure or union may have any type other
// than a variably modified type.
if (!InvalidDecl && T->isVariablyModifiedType()) {
  if (!tryToFixVariablyModifiedVarType(
          TInfo, T, Loc, diag::err_typecheck_field_variable_size))
    InvalidDecl = true;
}

// Fields can not have abstract class types
if (!InvalidDecl && RequireNonAbstractType(Loc, T,
                                           diag::err_abstract_type_in_decl,
                                           AbstractFieldType))
  InvalidDecl = true;

bool ZeroWidth = false;
if (InvalidDecl)
  BitWidth = nullptr;
// If this is declared as a bit-field, check the bit-field.
if (BitWidth) {
  BitWidth = VerifyBitField(Loc, II, T, Record->isMsStruct(Context), BitWidth,
                            &ZeroWidth).get();
  if (!BitWidth) {
    InvalidDecl = true;
    BitWidth = nullptr;
    ZeroWidth = false;
  }
}

// Check that 'mutable' is consistent with the type of the declaration.
if (!InvalidDecl && Mutable) {
  unsigned DiagID = 0;
  if (T->isReferenceType())
    DiagID = getLangOpts().MSVCCompat ? diag::ext_mutable_reference
                                      : diag::err_mutable_reference;
  else if (T.isConstQualified())
    DiagID = diag::err_mutable_const;

  if (DiagID) {
    SourceLocation ErrLoc = Loc;
    if (D && D->getDeclSpec().getStorageClassSpecLoc().isValid())
      ErrLoc = D->getDeclSpec().getStorageClassSpecLoc();
    Diag(ErrLoc, DiagID);
    if (DiagID != diag::ext_mutable_reference) {
      Mutable = false;
      InvalidDecl = true;
    }
  }
}

// C++11 [class.union]p8 (DR1460):
//   At most one variant member of a union may have a
//   brace-or-equal-initializer.
if (InitStyle != ICIS_NoInit)
  checkDuplicateDefaultInit(*this, cast<CXXRecordDecl>(Record), Loc);

FieldDecl *NewFD = FieldDecl::Create(Context, Record, TSSL, Loc, II, T, TInfo,
                                     BitWidth, Mutable, InitStyle);
if (InvalidDecl)
  NewFD->setInvalidDecl();

if (PrevDecl && !isa<TagDecl>(PrevDecl)) {
  Diag(Loc, diag::err_duplicate_member) << II;
  Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
  NewFD->setInvalidDecl();
}

if (!InvalidDecl && getLangOpts().CPlusPlus) {
  if (Record->isUnion()) {
    if (const RecordType *RT = EltTy->getAs<RecordType>()) {
      CXXRecordDecl* RDecl = cast<CXXRecordDecl>(RT->getDecl());
      if (RDecl->getDefinition()) {
        // C++ [class.union]p1: An object of a class with a non-trivial
        // constructor, a non-trivial copy constructor, a non-trivial
        // destructor, or a non-trivial copy assignment operator
        // cannot be a member of a union, nor can an array of such
        // objects.
        if (CheckNontrivialField(NewFD))
          NewFD->setInvalidDecl();
      }
    }

    // C++ [class.union]p1: If a union contains a member of reference type,
    // the program is ill-formed, except when compiling with MSVC extensions
    // enabled.
    if (EltTy->isReferenceType()) {
      Diag(NewFD->getLocation(), getLangOpts().MicrosoftExt ?
                                  diag::ext_union_member_of_reference_type :
                                  diag::err_union_member_of_reference_type)
        << NewFD->getDeclName() << EltTy;
      if (!getLangOpts().MicrosoftExt)
        NewFD->setInvalidDecl();
    }
  }
}

// FIXME: We need to pass in the attributes given an AST
// representation, not a parser representation.
if (D) {
  // FIXME: The current scope is almost... but not entirely... correct here.
  ProcessDeclAttributes(getCurScope(), NewFD, *D);

  if (NewFD->hasAttrs())
    CheckAlignasUnderalignment(NewFD);
}

// In auto-retain/release, infer strong retension for fields of
// retainable type.
if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewFD))
  NewFD->setInvalidDecl();

if (T.isObjCGCWeak())
  Diag(Loc, diag::warn_attribute_weak_on_field);

// PPC MMA non-pointer types are not allowed as field types.
if (Context.getTargetInfo().getTriple().isPPC64() &&
    CheckPPCMMAType(T, NewFD->getLocation()))
  NewFD->setInvalidDecl();

NewFD->setAccess(AS);
return NewFD;
17009}

17011bool Sema::CheckNontrivialField(FieldDecl *FD) {
assert(FD)((void)0);
assert(getLangOpts().CPlusPlus && "valid check only for C++")((void)0);

if (FD->isInvalidDecl() || FD->getType()->isDependentType())
  return false;

QualType EltTy = Context.getBaseElementType(FD->getType());
if (const RecordType *RT = EltTy->getAs<RecordType>()) {
  CXXRecordDecl *RDecl = cast<CXXRecordDecl>(RT->getDecl());
  if (RDecl->getDefinition()) {
    // We check for copy constructors before constructors
    // because otherwise we'll never get complaints about
    // copy constructors.

    CXXSpecialMember member = CXXInvalid;
    // We're required to check for any non-trivial constructors. Since the
    // implicit default constructor is suppressed if there are any
    // user-declared constructors, we just need to check that there is a
    // trivial default constructor and a trivial copy constructor. (We don't
    // worry about move constructors here, since this is a C++98 check.)
    if (RDecl->hasNonTrivialCopyConstructor())
      member = CXXCopyConstructor;
    else if (!RDecl->hasTrivialDefaultConstructor())
      member = CXXDefaultConstructor;
    else if (RDecl->hasNonTrivialCopyAssignment())
      member = CXXCopyAssignment;
    else if (RDecl->hasNonTrivialDestructor())
      member = CXXDestructor;

    if (member != CXXInvalid) {
      if (!getLangOpts().CPlusPlus11 &&
          getLangOpts().ObjCAutoRefCount && RDecl->hasObjectMember()) {
        // Objective-C++ ARC: it is an error to have a non-trivial field of
        // a union. However, system headers in Objective-C programs
        // occasionally have Objective-C lifetime objects within unions,
        // and rather than cause the program to fail, we make those
        // members unavailable.
        SourceLocation Loc = FD->getLocation();
        if (getSourceManager().isInSystemHeader(Loc)) {
          if (!FD->hasAttr<UnavailableAttr>())
            FD->addAttr(UnavailableAttr::CreateImplicit(Context, "",
                          UnavailableAttr::IR_ARCFieldWithOwnership, Loc));
          return false;
        }
      }

      Diag(FD->getLocation(), getLangOpts().CPlusPlus11 ?
             diag::warn_cxx98_compat_nontrivial_union_or_anon_struct_member :
             diag::err_illegal_union_or_anon_struct_member)
        << FD->getParent()->isUnion() << FD->getDeclName() << member;
      DiagnoseNontrivial(RDecl, member);
      return !getLangOpts().CPlusPlus11;
    }
  }
}

return false;
17069}

17071/// TranslateIvarVisibility - Translate visibility from a token ID to an
17072///  AST enum value.
17073static ObjCIvarDecl::AccessControl
17074TranslateIvarVisibility(tok::ObjCKeywordKind ivarVisibility) {
switch (ivarVisibility) {
default: llvm_unreachable("Unknown visitibility kind")__builtin_unreachable();
case tok::objc_private: return ObjCIvarDecl::Private;
case tok::objc_public: return ObjCIvarDecl::Public;
case tok::objc_protected: return ObjCIvarDecl::Protected;
case tok::objc_package: return ObjCIvarDecl::Package;
}
17082}

17084/// ActOnIvar - Each ivar field of an objective-c class is passed into this
17085/// in order to create an IvarDecl object for it.
17086Decl *Sema::ActOnIvar(Scope *S,
                              SourceLocation DeclStart,
                              Declarator &D, Expr *BitfieldWidth,
                              tok::ObjCKeywordKind Visibility) {

IdentifierInfo *II = D.getIdentifier();
Expr *BitWidth = (Expr*)BitfieldWidth;
SourceLocation Loc = DeclStart;
if (II) Loc = D.getIdentifierLoc();

// FIXME: Unnamed fields can be handled in various different ways, for
// example, unnamed unions inject all members into the struct namespace!

TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
QualType T = TInfo->getType();

if (BitWidth) {
  // 6.7.2.1p3, 6.7.2.1p4
  BitWidth = VerifyBitField(Loc, II, T, /*IsMsStruct*/false, BitWidth).get();
  if (!BitWidth)
    D.setInvalidType();
} else {
  // Not a bitfield.

  // validate II.

}
if (T->isReferenceType()) {
  Diag(Loc, diag::err_ivar_reference_type);
  D.setInvalidType();
}
// C99 6.7.2.1p8: A member of a structure or union may have any type other
// than a variably modified type.
else if (T->isVariablyModifiedType()) {
  if (!tryToFixVariablyModifiedVarType(
          TInfo, T, Loc, diag::err_typecheck_ivar_variable_size))
    D.setInvalidType();
}

// Get the visibility (access control) for this ivar.
ObjCIvarDecl::AccessControl ac =
  Visibility != tok::objc_not_keyword ? TranslateIvarVisibility(Visibility)
                                      : ObjCIvarDecl::None;
// Must set ivar's DeclContext to its enclosing interface.
ObjCContainerDecl *EnclosingDecl = cast<ObjCContainerDecl>(CurContext);
if (!EnclosingDecl || EnclosingDecl->isInvalidDecl())
  return nullptr;
ObjCContainerDecl *EnclosingContext;
if (ObjCImplementationDecl *IMPDecl =
    dyn_cast<ObjCImplementationDecl>(EnclosingDecl)) {
  if (LangOpts.ObjCRuntime.isFragile()) {
  // Case of ivar declared in an implementation. Context is that of its class.
    EnclosingContext = IMPDecl->getClassInterface();
    assert(EnclosingContext && "Implementation has no class interface!")((void)0);
  }
  else
    EnclosingContext = EnclosingDecl;
} else {
  if (ObjCCategoryDecl *CDecl =
      dyn_cast<ObjCCategoryDecl>(EnclosingDecl)) {
    if (LangOpts.ObjCRuntime.isFragile() || !CDecl->IsClassExtension()) {
      Diag(Loc, diag::err_misplaced_ivar) << CDecl->IsClassExtension();
      return nullptr;
    }
  }
  EnclosingContext = EnclosingDecl;
}

// Construct the decl.
ObjCIvarDecl *NewID = ObjCIvarDecl::Create(Context, EnclosingContext,
                                           DeclStart, Loc, II, T,
                                           TInfo, ac, (Expr *)BitfieldWidth);

if (II) {
  NamedDecl *PrevDecl = LookupSingleName(S, II, Loc, LookupMemberName,
                                         ForVisibleRedeclaration);
  if (PrevDecl && isDeclInScope(PrevDecl, EnclosingContext, S)
      && !isa<TagDecl>(PrevDecl)) {
    Diag(Loc, diag::err_duplicate_member) << II;
    Diag(PrevDecl->getLocation(), diag::note_previous_declaration);
    NewID->setInvalidDecl();
  }
}

// Process attributes attached to the ivar.
ProcessDeclAttributes(S, NewID, D);

if (D.isInvalidType())
  NewID->setInvalidDecl();

// In ARC, infer 'retaining' for ivars of retainable type.
if (getLangOpts().ObjCAutoRefCount && inferObjCARCLifetime(NewID))
  NewID->setInvalidDecl();

if (D.getDeclSpec().isModulePrivateSpecified())
  NewID->setModulePrivate();

if (II) {
  // FIXME: When interfaces are DeclContexts, we'll need to add
  // these to the interface.
  S->AddDecl(NewID);
  IdResolver.AddDecl(NewID);
}

if (LangOpts.ObjCRuntime.isNonFragile() &&
    !NewID->isInvalidDecl() && isa<ObjCInterfaceDecl>(EnclosingDecl))
  Diag(Loc, diag::warn_ivars_in_interface);

return NewID;
17195}

17197/// ActOnLastBitfield - This routine handles synthesized bitfields rules for
17198/// class and class extensions. For every class \@interface and class
17199/// extension \@interface, if the last ivar is a bitfield of any type,
17200/// then add an implicit `char :0` ivar to the end of that interface.
17201void Sema::ActOnLastBitfield(SourceLocation DeclLoc,
                           SmallVectorImpl<Decl *> &AllIvarDecls) {
if (LangOpts.ObjCRuntime.isFragile() || AllIvarDecls.empty())
  return;

Decl *ivarDecl = AllIvarDecls[AllIvarDecls.size()-1];
ObjCIvarDecl *Ivar = cast<ObjCIvarDecl>(ivarDecl);

if (!Ivar->isBitField() || Ivar->isZeroLengthBitField(Context))
  return;
ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(CurContext);
if (!ID) {
  if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(CurContext)) {
    if (!CD->IsClassExtension())
      return;
  }
  // No need to add this to end of @implementation.
  else
    return;
}
// All conditions are met. Add a new bitfield to the tail end of ivars.
llvm::APInt Zero(Context.getTypeSize(Context.IntTy), 0);
Expr * BW = IntegerLiteral::Create(Context, Zero, Context.IntTy, DeclLoc);

Ivar = ObjCIvarDecl::Create(Context, cast<ObjCContainerDecl>(CurContext),
                            DeclLoc, DeclLoc, nullptr,
                            Context.CharTy,
                            Context.getTrivialTypeSourceInfo(Context.CharTy,
                                                             DeclLoc),
                            ObjCIvarDecl::Private, BW,
                            true);
AllIvarDecls.push_back(Ivar);
17233}

17235void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl,
                     ArrayRef<Decl *> Fields, SourceLocation LBrac,
                     SourceLocation RBrac,
                     const ParsedAttributesView &Attrs) {
assert(EnclosingDecl && "missing record or interface decl")((void)0);

// If this is an Objective-C @implementation or category and we have
// new fields here we should reset the layout of the interface since
// it will now change.
if (!Fields.empty() && isa<ObjCContainerDecl>(EnclosingDecl)) {
  ObjCContainerDecl *DC = cast<ObjCContainerDecl>(EnclosingDecl);
  switch (DC->getKind()) {
  default: break;
  case Decl::ObjCCategory:
    Context.ResetObjCLayout(cast<ObjCCategoryDecl>(DC)->getClassInterface());
    break;
  case Decl::ObjCImplementation:
    Context.
      ResetObjCLayout(cast<ObjCImplementationDecl>(DC)->getClassInterface());
    break;
  }
}

RecordDecl *Record = dyn_cast<RecordDecl>(EnclosingDecl);
CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(EnclosingDecl);

// Start counting up the number of named members; make sure to include
// members of anonymous structs and unions in the total.
unsigned NumNamedMembers = 0;
if (Record) {
  for (const auto *I : Record->decls()) {
    if (const auto *IFD = dyn_cast<IndirectFieldDecl>(I))
      if (IFD->getDeclName())
        ++NumNamedMembers;
  }
}

// Verify that all the fields are okay.
SmallVector<FieldDecl*, 32> RecFields;

for (ArrayRef<Decl *>::iterator i = Fields.begin(), end = Fields.end();
     i != end; ++i) {
  FieldDecl *FD = cast<FieldDecl>(*i);

  // Get the type for the field.
  const Type *FDTy = FD->getType().getTypePtr();

  if (!FD->isAnonymousStructOrUnion()) {
    // Remember all fields written by the user.
    RecFields.push_back(FD);
  }

  // If the field is already invalid for some reason, don't emit more
  // diagnostics about it.
  if (FD->isInvalidDecl()) {
    EnclosingDecl->setInvalidDecl();
    continue;
  }

  // C99 6.7.2.1p2:
  //   A structure or union shall not contain a member with
  //   incomplete or function type (hence, a structure shall not
  //   contain an instance of itself, but may contain a pointer to
  //   an instance of itself), except that the last member of a
  //   structure with more than one named member may have incomplete
  //   array type; such a structure (and any union containing,
  //   possibly recursively, a member that is such a structure)
  //   shall not be a member of a structure or an element of an
  //   array.
  bool IsLastField = (i + 1 == Fields.end());
  if (FDTy->isFunctionType()) {
    // Field declared as a function.
    Diag(FD->getLocation(), diag::err_field_declared_as_function)
      << FD->getDeclName();
    FD->setInvalidDecl();
    EnclosingDecl->setInvalidDecl();
    continue;
  } else if (FDTy->isIncompleteArrayType() &&
             (Record || isa<ObjCContainerDecl>(EnclosingDecl))) {
    if (Record) {
      // Flexible array member.
      // Microsoft and g++ is more permissive regarding flexible array.
      // It will accept flexible array in union and also
      // as the sole element of a struct/class.
      unsigned DiagID = 0;
      if (!Record->isUnion() && !IsLastField) {
        Diag(FD->getLocation(), diag::err_flexible_array_not_at_end)
          << FD->getDeclName() << FD->getType() << Record->getTagKind();
        Diag((*(i + 1))->getLocation(), diag::note_next_field_declaration);
        FD->setInvalidDecl();
        EnclosingDecl->setInvalidDecl();
        continue;
      } else if (Record->isUnion())
        DiagID = getLangOpts().MicrosoftExt
                     ? diag::ext_flexible_array_union_ms
                     : getLangOpts().CPlusPlus
                           ? diag::ext_flexible_array_union_gnu
                           : diag::err_flexible_array_union;
      else if (NumNamedMembers < 1)
        DiagID = getLangOpts().MicrosoftExt
                     ? diag::ext_flexible_array_empty_aggregate_ms
                     : getLangOpts().CPlusPlus
                           ? diag::ext_flexible_array_empty_aggregate_gnu
                           : diag::err_flexible_array_empty_aggregate;

      if (DiagID)
        Diag(FD->getLocation(), DiagID) << FD->getDeclName()
                                        << Record->getTagKind();
      // While the layout of types that contain virtual bases is not specified
      // by the C++ standard, both the Itanium and Microsoft C++ ABIs place
      // virtual bases after the derived members.  This would make a flexible
      // array member declared at the end of an object not adjacent to the end
      // of the type.
      if (CXXRecord && CXXRecord->getNumVBases() != 0)
        Diag(FD->getLocation(), diag::err_flexible_array_virtual_base)
            << FD->getDeclName() << Record->getTagKind();
      if (!getLangOpts().C99)
        Diag(FD->getLocation(), diag::ext_c99_flexible_array_member)
          << FD->getDeclName() << Record->getTagKind();

      // If the element type has a non-trivial destructor, we would not
      // implicitly destroy the elements, so disallow it for now.
      //
      // FIXME: GCC allows this. We should probably either implicitly delete
      // the destructor of the containing class, or just allow this.
      QualType BaseElem = Context.getBaseElementType(FD->getType());
      if (!BaseElem->isDependentType() && BaseElem.isDestructedType()) {
        Diag(FD->getLocation(), diag::err_flexible_array_has_nontrivial_dtor)
          << FD->getDeclName() << FD->getType();
        FD->setInvalidDecl();
        EnclosingDecl->setInvalidDecl();
        continue;
      }
      // Okay, we have a legal flexible array member at the end of the struct.
      Record->setHasFlexibleArrayMember(true);
    } else {
      // In ObjCContainerDecl ivars with incomplete array type are accepted,
      // unless they are followed by another ivar. That check is done
      // elsewhere, after synthesized ivars are known.
    }
  } else if (!FDTy->isDependentType() &&
             RequireCompleteSizedType(
                 FD->getLocation(), FD->getType(),
                 diag::err_field_incomplete_or_sizeless)) {
    // Incomplete type
    FD->setInvalidDecl();
    EnclosingDecl->setInvalidDecl();
    continue;
  } else if (const RecordType *FDTTy = FDTy->getAs<RecordType>()) {
    if (Record && FDTTy->getDecl()->hasFlexibleArrayMember()) {
      // A type which contains a flexible array member is considered to be a
      // flexible array member.
      Record->setHasFlexibleArrayMember(true);
      if (!Record->isUnion()) {
        // If this is a struct/class and this is not the last element, reject
        // it.  Note that GCC supports variable sized arrays in the middle of
        // structures.
        if (!IsLastField)
          Diag(FD->getLocation(), diag::ext_variable_sized_type_in_struct)
            << FD->getDeclName() << FD->getType();
        else {
          // We support flexible arrays at the end of structs in
          // other structs as an extension.
          Diag(FD->getLocation(), diag::ext_flexible_array_in_struct)
            << FD->getDeclName();
        }
      }
    }
    if (isa<ObjCContainerDecl>(EnclosingDecl) &&
        RequireNonAbstractType(FD->getLocation(), FD->getType(),
                               diag::err_abstract_type_in_decl,
                               AbstractIvarType)) {
      // Ivars can not have abstract class types
      FD->setInvalidDecl();
    }
    if (Record && FDTTy->getDecl()->hasObjectMember())
      Record->setHasObjectMember(true);
    if (Record && FDTTy->getDecl()->hasVolatileMember())
      Record->setHasVolatileMember(true);
  } else if (FDTy->isObjCObjectType()) {
    /// A field cannot be an Objective-c object
    Diag(FD->getLocation(), diag::err_statically_allocated_object)
      << FixItHint::CreateInsertion(FD->getLocation(), "*");
    QualType T = Context.getObjCObjectPointerType(FD->getType());
    FD->setType(T);
  } else if (Record && Record->isUnion() &&
             FD->getType().hasNonTrivialObjCLifetime() &&
             getSourceManager().isInSystemHeader(FD->getLocation()) &&
             !getLangOpts().CPlusPlus && !FD->hasAttr<UnavailableAttr>() &&
             (FD->getType().getObjCLifetime() != Qualifiers::OCL_Strong ||
              !Context.hasDirectOwnershipQualifier(FD->getType()))) {
    // For backward compatibility, fields of C unions declared in system
    // headers that have non-trivial ObjC ownership qualifications are marked
    // as unavailable unless the qualifier is explicit and __strong. This can
    // break ABI compatibility between programs compiled with ARC and MRR, but
    // is a better option than rejecting programs using those unions under
    // ARC.
    FD->addAttr(UnavailableAttr::CreateImplicit(
        Context, "", UnavailableAttr::IR_ARCFieldWithOwnership,
        FD->getLocation()));
  } else if (getLangOpts().ObjC &&
             getLangOpts().getGC() != LangOptions::NonGC && Record &&
             !Record->hasObjectMember()) {
    if (FD->getType()->isObjCObjectPointerType() ||
        FD->getType().isObjCGCStrong())
      Record->setHasObjectMember(true);
    else if (Context.getAsArrayType(FD->getType())) {
      QualType BaseType = Context.getBaseElementType(FD->getType());
      if (BaseType->isRecordType() &&
          BaseType->castAs<RecordType>()->getDecl()->hasObjectMember())
        Record->setHasObjectMember(true);
      else if (BaseType->isObjCObjectPointerType() ||
               BaseType.isObjCGCStrong())
             Record->setHasObjectMember(true);
    }
  }

  if (Record && !getLangOpts().CPlusPlus &&
      !shouldIgnoreForRecordTriviality(FD)) {
    QualType FT = FD->getType();
    if (FT.isNonTrivialToPrimitiveDefaultInitialize()) {
      Record->setNonTrivialToPrimitiveDefaultInitialize(true);
      if (FT.hasNonTrivialToPrimitiveDefaultInitializeCUnion() ||
          Record->isUnion())
        Record->setHasNonTrivialToPrimitiveDefaultInitializeCUnion(true);
    }
    QualType::PrimitiveCopyKind PCK = FT.isNonTrivialToPrimitiveCopy();
    if (PCK != QualType::PCK_Trivial && PCK != QualType::PCK_VolatileTrivial) {
      Record->setNonTrivialToPrimitiveCopy(true);
      if (FT.hasNonTrivialToPrimitiveCopyCUnion() || Record->isUnion())
        Record->setHasNonTrivialToPrimitiveCopyCUnion(true);
    }
    if (FT.isDestructedType()) {
      Record->setNonTrivialToPrimitiveDestroy(true);
      Record->setParamDestroyedInCallee(true);
      if (FT.hasNonTrivialToPrimitiveDestructCUnion() || Record->isUnion())
        Record->setHasNonTrivialToPrimitiveDestructCUnion(true);
    }

    if (const auto *RT = FT->getAs<RecordType>()) {
      if (RT->getDecl()->getArgPassingRestrictions() ==
          RecordDecl::APK_CanNeverPassInRegs)
        Record->setArgPassingRestrictions(RecordDecl::APK_CanNeverPassInRegs);
    } else if (FT.getQualifiers().getObjCLifetime() == Qualifiers::OCL_Weak)
      Record->setArgPassingRestrictions(RecordDecl::APK_CanNeverPassInRegs);
  }

  if (Record && FD->getType().isVolatileQualified())
    Record->setHasVolatileMember(true);
  // Keep track of the number of named members.
  if (FD->getIdentifier())
    ++NumNamedMembers;
}

// Okay, we successfully defined 'Record'.
if (Record) {
  bool Completed = false;
  if (CXXRecord) {
    if (!CXXRecord->isInvalidDecl()) {
      // Set access bits correctly on the directly-declared conversions.
      for (CXXRecordDecl::conversion_iterator
             I = CXXRecord->conversion_begin(),
             E = CXXRecord->conversion_end(); I != E; ++I)
        I.setAccess((*I)->getAccess());
    }

    // Add any implicitly-declared members to this class.
    AddImplicitlyDeclaredMembersToClass(CXXRecord);

    if (!CXXRecord->isDependentType()) {
      if (!CXXRecord->isInvalidDecl()) {
        // If we have virtual base classes, we may end up finding multiple
        // final overriders for a given virtual function. Check for this
        // problem now.
        if (CXXRecord->getNumVBases()) {
          CXXFinalOverriderMap FinalOverriders;
          CXXRecord->getFinalOverriders(FinalOverriders);

          for (CXXFinalOverriderMap::iterator M = FinalOverriders.begin(),
                                           MEnd = FinalOverriders.end();
               M != MEnd; ++M) {
            for (OverridingMethods::iterator SO = M->second.begin(),
                                          SOEnd = M->second.end();
                 SO != SOEnd; ++SO) {
              assert(SO->second.size() > 0 &&((void)0)
                     "Virtual function without overriding functions?")((void)0);
              if (SO->second.size() == 1)
                continue;

              // C++ [class.virtual]p2:
              //   In a derived class, if a virtual member function of a base
              //   class subobject has more than one final overrider the
              //   program is ill-formed.
              Diag(Record->getLocation(), diag::err_multiple_final_overriders)
                << (const NamedDecl *)M->first << Record;
              Diag(M->first->getLocation(),
                   diag::note_overridden_virtual_function);
              for (OverridingMethods::overriding_iterator
                        OM = SO->second.begin(),
                     OMEnd = SO->second.end();
                   OM != OMEnd; ++OM)
                Diag(OM->Method->getLocation(), diag::note_final_overrider)
                  << (const NamedDecl *)M->first << OM->Method->getParent();

              Record->setInvalidDecl();
            }
          }
          CXXRecord->completeDefinition(&FinalOverriders);
          Completed = true;
        }
      }
    }
  }

  if (!Completed)
    Record->completeDefinition();

  // Handle attributes before checking the layout.
  ProcessDeclAttributeList(S, Record, Attrs);

  // We may have deferred checking for a deleted destructor. Check now.
  if (CXXRecord) {
    auto *Dtor = CXXRecord->getDestructor();
    if (Dtor && Dtor->isImplicit() &&
        ShouldDeleteSpecialMember(Dtor, CXXDestructor)) {
      CXXRecord->setImplicitDestructorIsDeleted();
      SetDeclDeleted(Dtor, CXXRecord->getLocation());
    }
  }

  if (Record->hasAttrs()) {
    CheckAlignasUnderalignment(Record);

    if (const MSInheritanceAttr *IA = Record->getAttr<MSInheritanceAttr>())
      checkMSInheritanceAttrOnDefinition(cast<CXXRecordDecl>(Record),
                                         IA->getRange(), IA->getBestCase(),
                                         IA->getInheritanceModel());
  }

  // Check if the structure/union declaration is a type that can have zero
  // size in C. For C this is a language extension, for C++ it may cause
  // compatibility problems.
  bool CheckForZeroSize;
  if (!getLangOpts().CPlusPlus) {
    CheckForZeroSize = true;
  } else {
    // For C++ filter out types that cannot be referenced in C code.
    CXXRecordDecl *CXXRecord = cast<CXXRecordDecl>(Record);
    CheckForZeroSize =
        CXXRecord->getLexicalDeclContext()->isExternCContext() &&
        !CXXRecord->isDependentType() && !inTemplateInstantiation() &&
        CXXRecord->isCLike();
  }
  if (CheckForZeroSize) {
    bool ZeroSize = true;
    bool IsEmpty = true;
    unsigned NonBitFields = 0;
    for (RecordDecl::field_iterator I = Record->field_begin(),
                                    E = Record->field_end();
         (NonBitFields == 0 || ZeroSize) && I != E; ++I) {
      IsEmpty = false;
      if (I->isUnnamedBitfield()) {
        if (!I->isZeroLengthBitField(Context))
          ZeroSize = false;
      } else {
        ++NonBitFields;
        QualType FieldType = I->getType();
        if (FieldType->isIncompleteType() ||
            !Context.getTypeSizeInChars(FieldType).isZero())
          ZeroSize = false;
      }
    }

    // Empty structs are an extension in C (C99 6.7.2.1p7). They are
    // allowed in C++, but warn if its declaration is inside
    // extern "C" block.
    if (ZeroSize) {
      Diag(RecLoc, getLangOpts().CPlusPlus ?
                       diag::warn_zero_size_struct_union_in_extern_c :
                       diag::warn_zero_size_struct_union_compat)
        << IsEmpty << Record->isUnion() << (NonBitFields > 1);
    }

    // Structs without named members are extension in C (C99 6.7.2.1p7),
    // but are accepted by GCC.
    if (NonBitFields == 0 && !getLangOpts().CPlusPlus) {
      Diag(RecLoc, IsEmpty ? diag::ext_empty_struct_union :
                             diag::ext_no_named_members_in_struct_union)
        << Record->isUnion();
    }
  }
} else {
  ObjCIvarDecl **ClsFields =
    reinterpret_cast<ObjCIvarDecl**>(RecFields.data());
  if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(EnclosingDecl)) {
    ID->setEndOfDefinitionLoc(RBrac);
    // Add ivar's to class's DeclContext.
    for (unsigned i = 0, e = RecFields.size(); i != e; ++i) {
      ClsFields[i]->setLexicalDeclContext(ID);
      ID->addDecl(ClsFields[i]);
    }
    // Must enforce the rule that ivars in the base classes may not be
    // duplicates.
    if (ID->getSuperClass())
      DiagnoseDuplicateIvars(ID, ID->getSuperClass());
  } else if (ObjCImplementationDecl *IMPDecl =
                dyn_cast<ObjCImplementationDecl>(EnclosingDecl)) {
    assert(IMPDecl && "ActOnFields - missing ObjCImplementationDecl")((void)0);
    for (unsigned I = 0, N = RecFields.size(); I != N; ++I)
      // Ivar declared in @implementation never belongs to the implementation.
      // Only it is in implementation's lexical context.
      ClsFields[I]->setLexicalDeclContext(IMPDecl);
    CheckImplementationIvars(IMPDecl, ClsFields, RecFields.size(), RBrac);
    IMPDecl->setIvarLBraceLoc(LBrac);
    IMPDecl->setIvarRBraceLoc(RBrac);
  } else if (ObjCCategoryDecl *CDecl =
              dyn_cast<ObjCCategoryDecl>(EnclosingDecl)) {
    // case of ivars in class extension; all other cases have been
    // reported as errors elsewhere.
    // FIXME. Class extension does not have a LocEnd field.
    // CDecl->setLocEnd(RBrac);
    // Add ivar's to class extension's DeclContext.
    // Diagnose redeclaration of private ivars.
    ObjCInterfaceDecl *IDecl = CDecl->getClassInterface();
    for (unsigned i = 0, e = RecFields.size(); i != e; ++i) {
      if (IDecl) {
        if (const ObjCIvarDecl *ClsIvar =
            IDecl->getIvarDecl(ClsFields[i]->getIdentifier())) {
          Diag(ClsFields[i]->getLocation(),
               diag::err_duplicate_ivar_declaration);
          Diag(ClsIvar->getLocation(), diag::note_previous_definition);
          continue;
        }
        for (const auto *Ext : IDecl->known_extensions()) {
          if (const ObjCIvarDecl *ClsExtIvar
                = Ext->getIvarDecl(ClsFields[i]->getIdentifier())) {
            Diag(ClsFields[i]->getLocation(),
                 diag::err_duplicate_ivar_declaration);
            Diag(ClsExtIvar->getLocation(), diag::note_previous_definition);
            continue;
          }
        }
      }
      ClsFields[i]->setLexicalDeclContext(CDecl);
      CDecl->addDecl(ClsFields[i]);
    }
    CDecl->setIvarLBraceLoc(LBrac);
    CDecl->setIvarRBraceLoc(RBrac);
  }
}
17685}

17687/// Determine whether the given integral value is representable within
17688/// the given type T.
17689static bool isRepresentableIntegerValue(ASTContext &Context,
                                      llvm::APSInt &Value,
                                      QualType T) {
assert((T->isIntegralType(Context) || T->isEnumeralType()) &&((void)0)
       "Integral type required!")((void)0);
unsigned BitWidth = Context.getIntWidth(T);

if (Value.isUnsigned() || Value.isNonNegative()) {
  if (T->isSignedIntegerOrEnumerationType())
    --BitWidth;
  return Value.getActiveBits() <= BitWidth;
}
return Value.getMinSignedBits() <= BitWidth;
17702}

17704// Given an integral type, return the next larger integral type
17705// (or a NULL type of no such type exists).
17706static QualType getNextLargerIntegralType(ASTContext &Context, QualType T) {
// FIXME: Int128/UInt128 support, which also needs to be introduced into
// enum checking below.
assert((T->isIntegralType(Context) ||((void)0)
       T->isEnumeralType()) && "Integral type required!")((void)0);
const unsigned NumTypes = 4;
QualType SignedIntegralTypes[NumTypes] = {
  Context.ShortTy, Context.IntTy, Context.LongTy, Context.LongLongTy
};
QualType UnsignedIntegralTypes[NumTypes] = {
  Context.UnsignedShortTy, Context.UnsignedIntTy, Context.UnsignedLongTy,
  Context.UnsignedLongLongTy
};

unsigned BitWidth = Context.getTypeSize(T);
QualType *Types = T->isSignedIntegerOrEnumerationType()? SignedIntegralTypes
                                                      : UnsignedIntegralTypes;
for (unsigned I = 0; I != NumTypes; ++I)
  if (Context.getTypeSize(Types[I]) > BitWidth)
    return Types[I];

return QualType();
17728}

17730EnumConstantDecl *Sema::CheckEnumConstant(EnumDecl *Enum,
                                        EnumConstantDecl *LastEnumConst,
                                        SourceLocation IdLoc,
                                        IdentifierInfo *Id,
                                        Expr *Val) {
unsigned IntWidth = Context.getTargetInfo().getIntWidth();
llvm::APSInt EnumVal(IntWidth);
QualType EltTy;

if (Val && DiagnoseUnexpandedParameterPack(Val, UPPC_EnumeratorValue))
  Val = nullptr;

if (Val)
  Val = DefaultLvalueConversion(Val).get();

if (Val) {
  if (Enum->isDependentType() || Val->isTypeDependent())
    EltTy = Context.DependentTy;
  else {
    // FIXME: We don't allow folding in C++11 mode for an enum with a fixed
    // underlying type, but do allow it in all other contexts.
    if (getLangOpts().CPlusPlus11 && Enum->isFixed()) {
      // C++11 [dcl.enum]p5: If the underlying type is fixed, [...] the
      // constant-expression in the enumerator-definition shall be a converted
      // constant expression of the underlying type.
      EltTy = Enum->getIntegerType();
      ExprResult Converted =
        CheckConvertedConstantExpression(Val, EltTy, EnumVal,
                                         CCEK_Enumerator);
      if (Converted.isInvalid())
        Val = nullptr;
      else
        Val = Converted.get();
    } else if (!Val->isValueDependent() &&
               !(Val =
                     VerifyIntegerConstantExpression(Val, &EnumVal, AllowFold)
                         .get())) {
      // C99 6.7.2.2p2: Make sure we have an integer constant expression.
    } else {
      if (Enum->isComplete()) {
        EltTy = Enum->getIntegerType();

        // In Obj-C and Microsoft mode, require the enumeration value to be
        // representable in the underlying type of the enumeration. In C++11,
        // we perform a non-narrowing conversion as part of converted constant
        // expression checking.
        if (!isRepresentableIntegerValue(Context, EnumVal, EltTy)) {
          if (Context.getTargetInfo()
                  .getTriple()
                  .isWindowsMSVCEnvironment()) {
            Diag(IdLoc, diag::ext_enumerator_too_large) << EltTy;
          } else {
            Diag(IdLoc, diag::err_enumerator_too_large) << EltTy;
          }
        }

        // Cast to the underlying type.
        Val = ImpCastExprToType(Val, EltTy,
                                EltTy->isBooleanType() ? CK_IntegralToBoolean
                                                       : CK_IntegralCast)
                  .get();
      } else if (getLangOpts().CPlusPlus) {
        // C++11 [dcl.enum]p5:
        //   If the underlying type is not fixed, the type of each enumerator
        //   is the type of its initializing value:
        //     - If an initializer is specified for an enumerator, the
        //       initializing value has the same type as the expression.
        EltTy = Val->getType();
      } else {
        // C99 6.7.2.2p2:
        //   The expression that defines the value of an enumeration constant
        //   shall be an integer constant expression that has a value
        //   representable as an int.

        // Complain if the value is not representable in an int.
        if (!isRepresentableIntegerValue(Context, EnumVal, Context.IntTy))
          Diag(IdLoc, diag::ext_enum_value_not_int)
            << toString(EnumVal, 10) << Val->getSourceRange()
            << (EnumVal.isUnsigned() || EnumVal.isNonNegative());
        else if (!Context.hasSameType(Val->getType(), Context.IntTy)) {
          // Force the type of the expression to 'int'.
          Val = ImpCastExprToType(Val, Context.IntTy, CK_IntegralCast).get();
        }
        EltTy = Val->getType();
      }
    }
  }
}

if (!Val) {
  if (Enum->isDependentType())
    EltTy = Context.DependentTy;
  else if (!LastEnumConst) {
    // C++0x [dcl.enum]p5:
    //   If the underlying type is not fixed, the type of each enumerator
    //   is the type of its initializing value:
    //     - If no initializer is specified for the first enumerator, the
    //       initializing value has an unspecified integral type.
    //
    // GCC uses 'int' for its unspecified integral type, as does
    // C99 6.7.2.2p3.
    if (Enum->isFixed()) {
      EltTy = Enum->getIntegerType();
    }
    else {
      EltTy = Context.IntTy;
    }
  } else {
    // Assign the last value + 1.
    EnumVal = LastEnumConst->getInitVal();
    ++EnumVal;
    EltTy = LastEnumConst->getType();

    // Check for overflow on increment.
    if (EnumVal < LastEnumConst->getInitVal()) {
      // C++0x [dcl.enum]p5:
      //   If the underlying type is not fixed, the type of each enumerator
      //   is the type of its initializing value:
      //
      //     - Otherwise the type of the initializing value is the same as
      //       the type of the initializing value of the preceding enumerator
      //       unless the incremented value is not representable in that type,
      //       in which case the type is an unspecified integral type
      //       sufficient to contain the incremented value. If no such type
      //       exists, the program is ill-formed.
      QualType T = getNextLargerIntegralType(Context, EltTy);
      if (T.isNull() || Enum->isFixed()) {
        // There is no integral type larger enough to represent this
        // value. Complain, then allow the value to wrap around.
        EnumVal = LastEnumConst->getInitVal();
        EnumVal = EnumVal.zext(EnumVal.getBitWidth() * 2);
        ++EnumVal;
        if (Enum->isFixed())
          // When the underlying type is fixed, this is ill-formed.
          Diag(IdLoc, diag::err_enumerator_wrapped)
            << toString(EnumVal, 10)
            << EltTy;
        else
          Diag(IdLoc, diag::ext_enumerator_increment_too_large)
            << toString(EnumVal, 10);
      } else {
        EltTy = T;
      }

      // Retrieve the last enumerator's value, extent that type to the
      // type that is supposed to be large enough to represent the incremented
      // value, then increment.
      EnumVal = LastEnumConst->getInitVal();
      EnumVal.setIsSigned(EltTy->isSignedIntegerOrEnumerationType());
      EnumVal = EnumVal.zextOrTrunc(Context.getIntWidth(EltTy));
      ++EnumVal;

      // If we're not in C++, diagnose the overflow of enumerator values,
      // which in C99 means that the enumerator value is not representable in
      // an int (C99 6.7.2.2p2). However, we support GCC's extension that
      // permits enumerator values that are representable in some larger
      // integral type.
      if (!getLangOpts().CPlusPlus && !T.isNull())
        Diag(IdLoc, diag::warn_enum_value_overflow);
    } else if (!getLangOpts().CPlusPlus &&
               !isRepresentableIntegerValue(Context, EnumVal, EltTy)) {
      // Enforce C99 6.7.2.2p2 even when we compute the next value.
      Diag(IdLoc, diag::ext_enum_value_not_int)
        << toString(EnumVal, 10) << 1;
    }
  }
}

if (!EltTy->isDependentType()) {
  // Make the enumerator value match the signedness and size of the
  // enumerator's type.
  EnumVal = EnumVal.extOrTrunc(Context.getIntWidth(EltTy));
  EnumVal.setIsSigned(EltTy->isSignedIntegerOrEnumerationType());
}

return EnumConstantDecl::Create(Context, Enum, IdLoc, Id, EltTy,
                                Val, EnumVal);
17907}

17909Sema::SkipBodyInfo Sema::shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
                                              SourceLocation IILoc) {
if (!(getLangOpts().Modules || getLangOpts().ModulesLocalVisibility) ||
    !getLangOpts().CPlusPlus)
  return SkipBodyInfo();

// We have an anonymous enum definition. Look up the first enumerator to
// determine if we should merge the definition with an existing one and
// skip the body.
NamedDecl *PrevDecl = LookupSingleName(S, II, IILoc, LookupOrdinaryName,
                                       forRedeclarationInCurContext());
auto *PrevECD = dyn_cast_or_null<EnumConstantDecl>(PrevDecl);
if (!PrevECD)
  return SkipBodyInfo();

EnumDecl *PrevED = cast<EnumDecl>(PrevECD->getDeclContext());
NamedDecl *Hidden;
if (!PrevED->getDeclName() && !hasVisibleDefinition(PrevED, &Hidden)) {
  SkipBodyInfo Skip;
  Skip.Previous = Hidden;
  return Skip;
}

return SkipBodyInfo();
17933}

17935Decl *Sema::ActOnEnumConstant(Scope *S, Decl *theEnumDecl, Decl *lastEnumConst,
                            SourceLocation IdLoc, IdentifierInfo *Id,
                            const ParsedAttributesView &Attrs,
                            SourceLocation EqualLoc, Expr *Val) {
EnumDecl *TheEnumDecl = cast<EnumDecl>(theEnumDecl);
EnumConstantDecl *LastEnumConst =
  cast_or_null<EnumConstantDecl>(lastEnumConst);

// The scope passed in may not be a decl scope.  Zip up the scope tree until
// we find one that is.
S = getNonFieldDeclScope(S);

// Verify that there isn't already something declared with this name in this
// scope.
LookupResult R(*this, Id, IdLoc, LookupOrdinaryName, ForVisibleRedeclaration);
LookupName(R, S);
NamedDecl *PrevDecl = R.getAsSingle<NamedDecl>();

if (PrevDecl && PrevDecl->isTemplateParameter()) {
  // Maybe we will complain about the shadowed template parameter.
  DiagnoseTemplateParameterShadow(IdLoc, PrevDecl);
  // Just pretend that we didn't see the previous declaration.
  PrevDecl = nullptr;
}

// C++ [class.mem]p15:
// If T is the name of a class, then each of the following shall have a name
// different from T:
// - every enumerator of every member of class T that is an unscoped
// enumerated type
if (getLangOpts().CPlusPlus && !TheEnumDecl->isScoped())
  DiagnoseClassNameShadow(TheEnumDecl->getDeclContext(),
                          DeclarationNameInfo(Id, IdLoc));

EnumConstantDecl *New =
  CheckEnumConstant(TheEnumDecl, LastEnumConst, IdLoc, Id, Val);
if (!New)
  return nullptr;

if (PrevDecl) {
  if (!TheEnumDecl->isScoped() && isa<ValueDecl>(PrevDecl)) {
    // Check for other kinds of shadowing not already handled.
    CheckShadow(New, PrevDecl, R);
  }

  // When in C++, we may get a TagDecl with the same name; in this case the
  // enum constant will 'hide' the tag.
  assert((getLangOpts().CPlusPlus || !isa<TagDecl>(PrevDecl)) &&((void)0)
         "Received TagDecl when not in C++!")((void)0);
  if (!isa<TagDecl>(PrevDecl) && isDeclInScope(PrevDecl, CurContext, S)) {
    if (isa<EnumConstantDecl>(PrevDecl))
      Diag(IdLoc, diag::err_redefinition_of_enumerator) << Id;
    else
      Diag(IdLoc, diag::err_redefinition) << Id;
    notePreviousDefinition(PrevDecl, IdLoc);
    return nullptr;
  }
}

// Process attributes.
ProcessDeclAttributeList(S, New, Attrs);
AddPragmaAttributes(S, New);

// Register this decl in the current scope stack.
New->setAccess(TheEnumDecl->getAccess());
PushOnScopeChains(New, S);

ActOnDocumentableDecl(New);

return New;
18005}

18007// Returns true when the enum initial expression does not trigger the
18008// duplicate enum warning.  A few common cases are exempted as follows:
18009// Element2 = Element1
18010// Element2 = Element1 + 1
18011// Element2 = Element1 - 1
18012// Where Element2 and Element1 are from the same enum.
18013static bool ValidDuplicateEnum(EnumConstantDecl *ECD, EnumDecl *Enum) {
Expr *InitExpr = ECD->getInitExpr();
if (!InitExpr)
  return true;
InitExpr = InitExpr->IgnoreImpCasts();

if (BinaryOperator *BO = dyn_cast<BinaryOperator>(InitExpr)) {
  if (!BO->isAdditiveOp())
    return true;
  IntegerLiteral *IL = dyn_cast<IntegerLiteral>(BO->getRHS());
  if (!IL)
    return true;
  if (IL->getValue() != 1)
    return true;

  InitExpr = BO->getLHS();
}

// This checks if the elements are from the same enum.
DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(InitExpr);
if (!DRE)
  return true;

EnumConstantDecl *EnumConstant = dyn_cast<EnumConstantDecl>(DRE->getDecl());
if (!EnumConstant)
  return true;

if (cast<EnumDecl>(TagDecl::castFromDeclContext(ECD->getDeclContext())) !=
    Enum)
  return true;

return false;
18045}

18047// Emits a warning when an element is implicitly set a value that
18048// a previous element has already been set to.
18049static void CheckForDuplicateEnumValues(Sema &S, ArrayRef<Decl *> Elements,
                                      EnumDecl *Enum, QualType EnumType) {
// Avoid anonymous enums
if (!Enum->getIdentifier())
  return;

// Only check for small enums.
if (Enum->getNumPositiveBits() > 63 || Enum->getNumNegativeBits() > 64)
  return;

if (S.Diags.isIgnored(diag::warn_duplicate_enum_values, Enum->getLocation()))
  return;

typedef SmallVector<EnumConstantDecl *, 3> ECDVector;
typedef SmallVector<std::unique_ptr<ECDVector>, 3> DuplicatesVector;

typedef llvm::PointerUnion<EnumConstantDecl*, ECDVector*> DeclOrVector;

// DenseMaps cannot contain the all ones int64_t value, so use unordered_map.
typedef std::unordered_map<int64_t, DeclOrVector> ValueToVectorMap;

// Use int64_t as a key to avoid needing special handling for map keys.
auto EnumConstantToKey = [](const EnumConstantDecl *D) {
  llvm::APSInt Val = D->getInitVal();
  return Val.isSigned() ? Val.getSExtValue() : Val.getZExtValue();
};

DuplicatesVector DupVector;
ValueToVectorMap EnumMap;

// Populate the EnumMap with all values represented by enum constants without
// an initializer.
for (auto *Element : Elements) {
  EnumConstantDecl *ECD = cast_or_null<EnumConstantDecl>(Element);

  // Null EnumConstantDecl means a previous diagnostic has been emitted for
  // this constant.  Skip this enum since it may be ill-formed.
  if (!ECD) {
    return;
  }

  // Constants with initalizers are handled in the next loop.
  if (ECD->getInitExpr())
    continue;

  // Duplicate values are handled in the next loop.
  EnumMap.insert({EnumConstantToKey(ECD), ECD});
}

if (EnumMap.size() == 0)
  return;

// Create vectors for any values that has duplicates.
for (auto *Element : Elements) {
  // The last loop returned if any constant was null.
  EnumConstantDecl *ECD = cast<EnumConstantDecl>(Element);
  if (!ValidDuplicateEnum(ECD, Enum))
    continue;

  auto Iter = EnumMap.find(EnumConstantToKey(ECD));
  if (Iter == EnumMap.end())
    continue;

  DeclOrVector& Entry = Iter->second;
  if (EnumConstantDecl *D = Entry.dyn_cast<EnumConstantDecl*>()) {
    // Ensure constants are different.
    if (D == ECD)
      continue;

    // Create new vector and push values onto it.
    auto Vec = std::make_unique<ECDVector>();
    Vec->push_back(D);
    Vec->push_back(ECD);

    // Update entry to point to the duplicates vector.
    Entry = Vec.get();

    // Store the vector somewhere we can consult later for quick emission of
    // diagnostics.
    DupVector.emplace_back(std::move(Vec));
    continue;
  }

  ECDVector *Vec = Entry.get<ECDVector*>();
  // Make sure constants are not added more than once.
  if (*Vec->begin() == ECD)
    continue;

  Vec->push_back(ECD);
}

// Emit diagnostics.
for (const auto &Vec : DupVector) {
  assert(Vec->size() > 1 && "ECDVector should have at least 2 elements.")((void)0);

  // Emit warning for one enum constant.
  auto *FirstECD = Vec->front();
  S.Diag(FirstECD->getLocation(), diag::warn_duplicate_enum_values)
    << FirstECD << toString(FirstECD->getInitVal(), 10)
    << FirstECD->getSourceRange();

  // Emit one note for each of the remaining enum constants with
  // the same value.
  for (auto *ECD : llvm::make_range(Vec->begin() + 1, Vec->end()))
    S.Diag(ECD->getLocation(), diag::note_duplicate_element)
      << ECD << toString(ECD->getInitVal(), 10)
      << ECD->getSourceRange();
}
18157}

18159bool Sema::IsValueInFlagEnum(const EnumDecl *ED, const llvm::APInt &Val,
                           bool AllowMask) const {
assert(ED->isClosedFlag() && "looking for value in non-flag or open enum")((void)0);
assert(ED->isCompleteDefinition() && "expected enum definition")((void)0);

auto R = FlagBitsCache.insert(std::make_pair(ED, llvm::APInt()));
llvm::APInt &FlagBits = R.first->second;

if (R.second) {
  for (auto *E : ED->enumerators()) {
    const auto &EVal = E->getInitVal();
    // Only single-bit enumerators introduce new flag values.
    if (EVal.isPowerOf2())
      FlagBits = FlagBits.zextOrSelf(EVal.getBitWidth()) | EVal;
  }
}

// A value is in a flag enum if either its bits are a subset of the enum's
// flag bits (the first condition) or we are allowing masks and the same is
// true of its complement (the second condition). When masks are allowed, we
// allow the common idiom of ~(enum1 | enum2) to be a valid enum value.
//
// While it's true that any value could be used as a mask, the assumption is
// that a mask will have all of the insignificant bits set. Anything else is
// likely a logic error.
llvm::APInt FlagMask = ~FlagBits.zextOrTrunc(Val.getBitWidth());
return !(FlagMask & Val) || (AllowMask && !(FlagMask & ~Val));
18186}

18188void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
                       Decl *EnumDeclX, ArrayRef<Decl *> Elements, Scope *S,
                       const ParsedAttributesView &Attrs) {
EnumDecl *Enum = cast<EnumDecl>(EnumDeclX);
QualType EnumType = Context.getTypeDeclType(Enum);

ProcessDeclAttributeList(S, Enum, Attrs);

if (Enum->isDependentType()) {
  for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
    EnumConstantDecl *ECD =
      cast_or_null<EnumConstantDecl>(Elements[i]);
    if (!ECD) continue;

    ECD->setType(EnumType);
  }

  Enum->completeDefinition(Context.DependentTy, Context.DependentTy, 0, 0);
  return;
}

// TODO: If the result value doesn't fit in an int, it must be a long or long
// long value.  ISO C does not support this, but GCC does as an extension,
// emit a warning.
unsigned IntWidth = Context.getTargetInfo().getIntWidth();
unsigned CharWidth = Context.getTargetInfo().getCharWidth();
unsigned ShortWidth = Context.getTargetInfo().getShortWidth();

// Verify that all the values are okay, compute the size of the values, and
// reverse the list.
unsigned NumNegativeBits = 0;
unsigned NumPositiveBits = 0;

// Keep track of whether all elements have type int.
bool AllElementsInt = true;

for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
  EnumConstantDecl *ECD =
    cast_or_null<EnumConstantDecl>(Elements[i]);
  if (!ECD) continue;  // Already issued a diagnostic.

  const llvm::APSInt &InitVal = ECD->getInitVal();

  // Keep track of the size of positive and negative values.
  if (InitVal.isUnsigned() || InitVal.isNonNegative())
    NumPositiveBits = std::max(NumPositiveBits,
                               (unsigned)InitVal.getActiveBits());
  else
    NumNegativeBits = std::max(NumNegativeBits,
                               (unsigned)InitVal.getMinSignedBits());

  // Keep track of whether every enum element has type int (very common).
  if (AllElementsInt)
    AllElementsInt = ECD->getType() == Context.IntTy;
}

// Figure out the type that should be used for this enum.
QualType BestType;
unsigned BestWidth;

// C++0x N3000 [conv.prom]p3:
//   An rvalue of an unscoped enumeration type whose underlying
//   type is not fixed can be converted to an rvalue of the first
//   of the following types that can represent all the values of
//   the enumeration: int, unsigned int, long int, unsigned long
//   int, long long int, or unsigned long long int.
// C99 6.4.4.3p2:
//   An identifier declared as an enumeration constant has type int.
// The C99 rule is modified by a gcc extension
QualType BestPromotionType;

bool Packed = Enum->hasAttr<PackedAttr>();
// -fshort-enums is the equivalent to specifying the packed attribute on all
// enum definitions.
if (LangOpts.ShortEnums)
  Packed = true;

// If the enum already has a type because it is fixed or dictated by the
// target, promote that type instead of analyzing the enumerators.
if (Enum->isComplete()) {
  BestType = Enum->getIntegerType();
  if (BestType->isPromotableIntegerType())
    BestPromotionType = Context.getPromotedIntegerType(BestType);
  else
    BestPromotionType = BestType;

  BestWidth = Context.getIntWidth(BestType);
}
else if (NumNegativeBits) {
  // If there is a negative value, figure out the smallest integer type (of
  // int/long/longlong) that fits.
  // If it's packed, check also if it fits a char or a short.
  if (Packed && NumNegativeBits <= CharWidth && NumPositiveBits < CharWidth) {
    BestType = Context.SignedCharTy;
    BestWidth = CharWidth;
  } else if (Packed && NumNegativeBits <= ShortWidth &&
             NumPositiveBits < ShortWidth) {
    BestType = Context.ShortTy;
    BestWidth = ShortWidth;
  } else if (NumNegativeBits <= IntWidth && NumPositiveBits < IntWidth) {
    BestType = Context.IntTy;
    BestWidth = IntWidth;
  } else {
    BestWidth = Context.getTargetInfo().getLongWidth();

    if (NumNegativeBits <= BestWidth && NumPositiveBits < BestWidth) {
      BestType = Context.LongTy;
    } else {
      BestWidth = Context.getTargetInfo().getLongLongWidth();

      if (NumNegativeBits > BestWidth || NumPositiveBits >= BestWidth)
        Diag(Enum->getLocation(), diag::ext_enum_too_large);
      BestType = Context.LongLongTy;
    }
  }
  BestPromotionType = (BestWidth <= IntWidth ? Context.IntTy : BestType);
} else {
  // If there is no negative value, figure out the smallest type that fits
  // all of the enumerator values.
  // If it's packed, check also if it fits a char or a short.
  if (Packed && NumPositiveBits <= CharWidth) {
    BestType = Context.UnsignedCharTy;
    BestPromotionType = Context.IntTy;
    BestWidth = CharWidth;
  } else if (Packed && NumPositiveBits <= ShortWidth) {
    BestType = Context.UnsignedShortTy;
    BestPromotionType = Context.IntTy;
    BestWidth = ShortWidth;
  } else if (NumPositiveBits <= IntWidth) {
    BestType = Context.UnsignedIntTy;
    BestWidth = IntWidth;
    BestPromotionType
      = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
                         ? Context.UnsignedIntTy : Context.IntTy;
  } else if (NumPositiveBits <=
             (BestWidth = Context.getTargetInfo().getLongWidth())) {
    BestType = Context.UnsignedLongTy;
    BestPromotionType
      = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
                         ? Context.UnsignedLongTy : Context.LongTy;
  } else {
    BestWidth = Context.getTargetInfo().getLongLongWidth();
    assert(NumPositiveBits <= BestWidth &&((void)0)
           "How could an initializer get larger than ULL?")((void)0);
    BestType = Context.UnsignedLongLongTy;
    BestPromotionType
      = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
                         ? Context.UnsignedLongLongTy : Context.LongLongTy;
  }
}

// Loop over all of the enumerator constants, changing their types to match
// the type of the enum if needed.
for (auto *D : Elements) {
  auto *ECD = cast_or_null<EnumConstantDecl>(D);
  if (!ECD) continue;  // Already issued a diagnostic.

  // Standard C says the enumerators have int type, but we allow, as an
  // extension, the enumerators to be larger than int size.  If each
  // enumerator value fits in an int, type it as an int, otherwise type it the
  // same as the enumerator decl itself.  This means that in "enum { X = 1U }"
  // that X has type 'int', not 'unsigned'.

  // Determine whether the value fits into an int.
  llvm::APSInt InitVal = ECD->getInitVal();

  // If it fits into an integer type, force it.  Otherwise force it to match
  // the enum decl type.
  QualType NewTy;
  unsigned NewWidth;
  bool NewSign;
  if (!getLangOpts().CPlusPlus &&
      !Enum->isFixed() &&
      isRepresentableIntegerValue(Context, InitVal, Context.IntTy)) {
    NewTy = Context.IntTy;
    NewWidth = IntWidth;
    NewSign = true;
  } else if (ECD->getType() == BestType) {
    // Already the right type!
    if (getLangOpts().CPlusPlus)
      // C++ [dcl.enum]p4: Following the closing brace of an
      // enum-specifier, each enumerator has the type of its
      // enumeration.
      ECD->setType(EnumType);
    continue;
  } else {
    NewTy = BestType;
    NewWidth = BestWidth;
    NewSign = BestType->isSignedIntegerOrEnumerationType();
  }

  // Adjust the APSInt value.
  InitVal = InitVal.extOrTrunc(NewWidth);
  InitVal.setIsSigned(NewSign);
  ECD->setInitVal(InitVal);

  // Adjust the Expr initializer and type.
  if (ECD->getInitExpr() &&
      !Context.hasSameType(NewTy, ECD->getInitExpr()->getType()))
    ECD->setInitExpr(ImplicitCastExpr::Create(
        Context, NewTy, CK_IntegralCast, ECD->getInitExpr(),
        /*base paths*/ nullptr, VK_PRValue, FPOptionsOverride()));
  if (getLangOpts().CPlusPlus)
    // C++ [dcl.enum]p4: Following the closing brace of an
    // enum-specifier, each enumerator has the type of its
    // enumeration.
    ECD->setType(EnumType);
  else
    ECD->setType(NewTy);
}

Enum->completeDefinition(BestType, BestPromotionType,
                         NumPositiveBits, NumNegativeBits);

CheckForDuplicateEnumValues(*this, Elements, Enum, EnumType);

if (Enum->isClosedFlag()) {
  for (Decl *D : Elements) {
    EnumConstantDecl *ECD = cast_or_null<EnumConstantDecl>(D);
    if (!ECD) continue;  // Already issued a diagnostic.

    llvm::APSInt InitVal = ECD->getInitVal();
    if (InitVal != 0 && !InitVal.isPowerOf2() &&
        !IsValueInFlagEnum(Enum, InitVal, true))
      Diag(ECD->getLocation(), diag::warn_flag_enum_constant_out_of_range)
        << ECD << Enum;
  }
}

// Now that the enum type is defined, ensure it's not been underaligned.
if (Enum->hasAttrs())
  CheckAlignasUnderalignment(Enum);
18420}

18422Decl *Sema::ActOnFileScopeAsmDecl(Expr *expr,
                                SourceLocation StartLoc,
                                SourceLocation EndLoc) {
StringLiteral *AsmString = cast<StringLiteral>(expr);

FileScopeAsmDecl *New = FileScopeAsmDecl::Create(Context, CurContext,
                                                 AsmString, StartLoc,
                                                 EndLoc);
CurContext->addDecl(New);
return New;
18432}

18434void Sema::ActOnPragmaRedefineExtname(IdentifierInfo* Name,
                                    IdentifierInfo* AliasName,
                                    SourceLocation PragmaLoc,
                                    SourceLocation NameLoc,
                                    SourceLocation AliasNameLoc) {
NamedDecl *PrevDecl = LookupSingleName(TUScope, Name, NameLoc,
                                       LookupOrdinaryName);
AttributeCommonInfo Info(AliasName, SourceRange(AliasNameLoc),
                         AttributeCommonInfo::AS_Pragma);
AsmLabelAttr *Attr = AsmLabelAttr::CreateImplicit(
    Context, AliasName->getName(), /*LiteralLabel=*/true, Info);

// If a declaration that:
// 1) declares a function or a variable
// 2) has external linkage
// already exists, add a label attribute to it.
if (PrevDecl && (isa<FunctionDecl>(PrevDecl) || isa<VarDecl>(PrevDecl))) {
  if (isDeclExternC(PrevDecl))
    PrevDecl->addAttr(Attr);
  else
    Diag(PrevDecl->getLocation(), diag::warn_redefine_extname_not_applied)
        << /*Variable*/(isa<FunctionDecl>(PrevDecl) ? 0 : 1) << PrevDecl;
// Otherwise, add a label atttibute to ExtnameUndeclaredIdentifiers.
} else
  (void)ExtnameUndeclaredIdentifiers.insert(std::make_pair(Name, Attr));
18459}

18461void Sema::ActOnPragmaWeakID(IdentifierInfo* Name,
                           SourceLocation PragmaLoc,
                           SourceLocation NameLoc) {
Decl *PrevDecl = LookupSingleName(TUScope, Name, NameLoc, LookupOrdinaryName);

if (PrevDecl) {
  PrevDecl->addAttr(WeakAttr::CreateImplicit(Context, PragmaLoc, AttributeCommonInfo::AS_Pragma));
} else {
  (void)WeakUndeclaredIdentifiers.insert(
    std::pair<IdentifierInfo*,WeakInfo>
      (Name, WeakInfo((IdentifierInfo*)nullptr, NameLoc)));
}
18473}

18475void Sema::ActOnPragmaWeakAlias(IdentifierInfo* Name,
                              IdentifierInfo* AliasName,
                              SourceLocation PragmaLoc,
                              SourceLocation NameLoc,
                              SourceLocation AliasNameLoc) {
Decl *PrevDecl = LookupSingleName(TUScope, AliasName, AliasNameLoc,
                                  LookupOrdinaryName);
WeakInfo W = WeakInfo(Name, NameLoc);

if (PrevDecl && (isa<FunctionDecl>(PrevDecl) || isa<VarDecl>(PrevDecl))) {
  if (!PrevDecl->hasAttr<AliasAttr>())
    if (NamedDecl *ND = dyn_cast<NamedDecl>(PrevDecl))
      DeclApplyPragmaWeak(TUScope, ND, W);
} else {
  (void)WeakUndeclaredIdentifiers.insert(
    std::pair<IdentifierInfo*,WeakInfo>(AliasName, W));
}
18492}

18494Decl *Sema::getObjCDeclContext() const {
return (dyn_cast_or_null<ObjCContainerDecl>(CurContext));
18496}

18498Sema::FunctionEmissionStatus Sema::getEmissionStatus(FunctionDecl *FD,
                                                   bool Final) {
assert(FD && "Expected non-null FunctionDecl")((void)0);

// SYCL functions can be template, so we check if they have appropriate
// attribute prior to checking if it is a template.
if (LangOpts.SYCLIsDevice && FD->hasAttr<SYCLKernelAttr>())
  return FunctionEmissionStatus::Emitted;

// Templates are emitted when they're instantiated.
if (FD->isDependentContext())
  return FunctionEmissionStatus::TemplateDiscarded;

// Check whether this function is an externally visible definition.
auto IsEmittedForExternalSymbol = [this, FD]() {
  // We have to check the GVA linkage of the function's *definition* -- if we
  // only have a declaration, we don't know whether or not the function will
  // be emitted, because (say) the definition could include "inline".
  FunctionDecl *Def = FD->getDefinition();

  return Def && !isDiscardableGVALinkage(
                    getASTContext().GetGVALinkageForFunction(Def));
};

if (LangOpts.OpenMPIsDevice) {
  // In OpenMP device mode we will not emit host only functions, or functions
  // we don't need due to their linkage.
  Optional<OMPDeclareTargetDeclAttr::DevTypeTy> DevTy =
      OMPDeclareTargetDeclAttr::getDeviceType(FD->getCanonicalDecl());
  // DevTy may be changed later by
  //  #pragma omp declare target to(*) device_type(*).
  // Therefore DevTy having no value does not imply host. The emission status
  // will be checked again at the end of compilation unit with Final = true.
  if (DevTy.hasValue())
    if (*DevTy == OMPDeclareTargetDeclAttr::DT_Host)
      return FunctionEmissionStatus::OMPDiscarded;
  // If we have an explicit value for the device type, or we are in a target
  // declare context, we need to emit all extern and used symbols.
  if (isInOpenMPDeclareTargetContext() || DevTy.hasValue())
    if (IsEmittedForExternalSymbol())
      return FunctionEmissionStatus::Emitted;
  // Device mode only emits what it must, if it wasn't tagged yet and needed,
  // we'll omit it.
  if (Final)
    return FunctionEmissionStatus::OMPDiscarded;
} else if (LangOpts.OpenMP > 45) {
  // In OpenMP host compilation prior to 5.0 everything was an emitted host
  // function. In 5.0, no_host was introduced which might cause a function to
  // be ommitted.
  Optional<OMPDeclareTargetDeclAttr::DevTypeTy> DevTy =
      OMPDeclareTargetDeclAttr::getDeviceType(FD->getCanonicalDecl());
  if (DevTy.hasValue())
    if (*DevTy == OMPDeclareTargetDeclAttr::DT_NoHost)
      return FunctionEmissionStatus::OMPDiscarded;
}

if (Final && LangOpts.OpenMP && !LangOpts.CUDA)
  return FunctionEmissionStatus::Emitted;

if (LangOpts.CUDA) {
  // When compiling for device, host functions are never emitted.  Similarly,
  // when compiling for host, device and global functions are never emitted.
  // (Technically, we do emit a host-side stub for global functions, but this
  // doesn't count for our purposes here.)
  Sema::CUDAFunctionTarget T = IdentifyCUDATarget(FD);
  if (LangOpts.CUDAIsDevice && T == Sema::CFT_Host)
    return FunctionEmissionStatus::CUDADiscarded;
  if (!LangOpts.CUDAIsDevice &&
      (T == Sema::CFT_Device || T == Sema::CFT_Global))
    return FunctionEmissionStatus::CUDADiscarded;

  if (IsEmittedForExternalSymbol())
    return FunctionEmissionStatus::Emitted;
}

// Otherwise, the function is known-emitted if it's in our set of
// known-emitted functions.
return FunctionEmissionStatus::Unknown;
18576}

18578bool Sema::shouldIgnoreInHostDeviceCheck(FunctionDecl *Callee) {
// Host-side references to a __global__ function refer to the stub, so the
// function itself is never emitted and therefore should not be marked.
// If we have host fn calls kernel fn calls host+device, the HD function
// does not get instantiated on the host. We model this by omitting at the
// call to the kernel from the callgraph. This ensures that, when compiling
// for host, only HD functions actually called from the host get marked as
// known-emitted.
return LangOpts.CUDA && !LangOpts.CUDAIsDevice &&
       IdentifyCUDATarget(Callee) == CFT_Global;
18588}