ASTContext.cpp

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//===- ASTContext.cpp - Context to hold long-lived AST nodes --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//  This file implements the ASTContext interface.
//
//===----------------------------------------------------------------------===//
 
#include "clang/AST/ASTContext.h"
#include "CXXABI.h"
#include "Interp/Context.h"
#include "clang/AST/APValue.h"
#include "clang/AST/ASTConcept.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/ASTTypeTraits.h"
#include "clang/AST/Attr.h"
#include "clang/AST/AttrIterator.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/Comment.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclContextInternals.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclOpenMP.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/DependenceFlags.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprConcepts.h"
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/Mangle.h"
#include "clang/AST/MangleNumberingContext.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/ParentMapContext.h"
#include "clang/AST/RawCommentList.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/TemplateBase.h"
#include "clang/AST/TemplateName.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/UnresolvedSet.h"
#include "clang/AST/VTableBuilder.h"
#include "clang/Basic/AddressSpaces.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/CommentOptions.h"
#include "clang/Basic/ExceptionSpecificationType.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/Linkage.h"
#include "clang/Basic/Module.h"
#include "clang/Basic/NoSanitizeList.h"
#include "clang/Basic/ObjCRuntime.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Basic/TargetCXXABI.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/XRayLists.h"
#include "llvm/ADT/APFixedPoint.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
#include "llvm/Support/Capacity.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TargetParser/Triple.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <cstdlib>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <tuple>
#include <utility>
 
using namespace clang;
 
enum FloatingRank {
  BFloat16Rank,
  Float16Rank,
  HalfRank,
  FloatRank,
  DoubleRank,
  LongDoubleRank,
  Float128Rank,
  Ibm128Rank
};
 
/// \returns location that is relevant when searching for Doc comments related
/// to \p D.
static SourceLocation getDeclLocForCommentSearch(const Decl *D,
                                                 SourceManager &SourceMgr) {
  assert(D);
 
  // User can not attach documentation to implicit declarations.
  if (D->isImplicit())
    return {};
 
  // User can not attach documentation to implicit instantiations.
  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
    if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return {};
  }
 
  if (const auto *VD = dyn_cast<VarDecl>(D)) {
    if (VD->isStaticDataMember() &&
        VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return {};
  }
 
  if (const auto *CRD = dyn_cast<CXXRecordDecl>(D)) {
    if (CRD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return {};
  }
 
  if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(D)) {
    TemplateSpecializationKind TSK = CTSD->getSpecializationKind();
    if (TSK == TSK_ImplicitInstantiation ||
        TSK == TSK_Undeclared)
      return {};
  }
 
  if (const auto *ED = dyn_cast<EnumDecl>(D)) {
    if (ED->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return {};
  }
  if (const auto *TD = dyn_cast<TagDecl>(D)) {
    // When tag declaration (but not definition!) is part of the
    // decl-specifier-seq of some other declaration, it doesn't get comment
    if (TD->isEmbeddedInDeclarator() && !TD->isCompleteDefinition())
      return {};
  }
  // TODO: handle comments for function parameters properly.
  if (isa<ParmVarDecl>(D))
    return {};
 
  // TODO: we could look up template parameter documentation in the template
  // documentation.
  if (isa<TemplateTypeParmDecl>(D) ||
      isa<NonTypeTemplateParmDecl>(D) ||
      isa<TemplateTemplateParmDecl>(D))
    return {};
 
  // Find declaration location.
  // For Objective-C declarations we generally don't expect to have multiple
  // declarators, thus use declaration starting location as the "declaration
  // location".
  // For all other declarations multiple declarators are used quite frequently,
  // so we use the location of the identifier as the "declaration location".
  if (isa<ObjCMethodDecl>(D) || isa<ObjCContainerDecl>(D) ||
      isa<ObjCPropertyDecl>(D) ||
      isa<RedeclarableTemplateDecl>(D) ||
      isa<ClassTemplateSpecializationDecl>(D) ||
      // Allow association with Y across {} in `typedef struct X {} Y`.
      isa<TypedefDecl>(D))
    return D->getBeginLoc();
 
  const SourceLocation DeclLoc = D->getLocation();
  if (DeclLoc.isMacroID()) {
    // There are (at least) three types of macros we care about here.
    //
    // 1. Macros that are used in the definition of a type outside the macro,
    //    with a comment attached at the macro call site.
    //    ```
    //    #define MAKE_NAME(Foo) Name##Foo
    //
    //    /// Comment is here, where we use the macro.
    //    struct MAKE_NAME(Foo) {
    //        int a;
    //        int b;
    //    };
    //    ```
    // 2. Macros that define whole things along with the comment.
    //    ```
    //    #define MAKE_METHOD(name) \
    //      /** Comment is here, inside the macro. */ \
    //      void name() {}
    //
    //    struct S {
    //      MAKE_METHOD(f)
    //    }
    //    ```
    // 3. Macros that both declare a type and name a decl outside the macro.
    //    ```
    //    /// Comment is here, where we use the macro.
    //    typedef NS_ENUM(NSInteger, Size) {
    //        SizeWidth,
    //        SizeHeight
    //    };
    //    ```
    //    In this case NS_ENUM declares am enum type, and uses the same name for
    //    the typedef declaration that appears outside the macro. The comment
    //    here should be applied to both declarations inside and outside the
    //    macro.
    //
    // We have found a Decl name that comes from inside a macro, but
    // Decl::getLocation() returns the place where the macro is being called.
    // If the declaration (and not just the name) resides inside the macro,
    // then we want to map Decl::getLocation() into the macro to where the
    // declaration and its attached comment (if any) were written.
    //
    // This mapping into the macro is done by mapping the location to its
    // spelling location, however even if the declaration is inside a macro,
    // the name's spelling can come from a macro argument (case 2 above). In
    // this case mapping the location to the spelling location finds the
    // argument's position (at `f` in MAKE_METHOD(`f`) above), which is not
    // where the declaration and its comment are located.
    //
    // To avoid this issue, we make use of Decl::getBeginLocation() instead.
    // While the declaration's position is where the name is written, the
    // comment is always attached to the begining of the declaration, not to
    // the name.
    //
    // In the first case, the begin location of the decl is outside the macro,
    // at the location of `typedef`. This is where the comment is found as
    // well. The begin location is not inside a macro, so it's spelling
    // location is the same.
    //
    // In the second case, the begin location of the decl is the call to the
    // macro, at `MAKE_METHOD`. However its spelling location is inside the
    // the macro at the location of `void`. This is where the comment is found
    // again.
    //
    // In the third case, there's no correct single behaviour. We want to use
    // the comment outside the macro for the definition that's inside the macro.
    // There is also a definition outside the macro, and we want the comment to
    // apply to both. The cases we care about here is NS_ENUM() and
    // NS_OPTIONS(). In general, if an enum is defined inside a macro, we should
    // try to find the comment there.
 
    // This is handling case 3 for NS_ENUM() and NS_OPTIONS(), which define
    // enum types inside the macro.
    if (isa<EnumDecl>(D)) {
      SourceLocation MacroCallLoc = SourceMgr.getExpansionLoc(DeclLoc);
      if (auto BufferRef =
              SourceMgr.getBufferOrNone(SourceMgr.getFileID(MacroCallLoc));
          BufferRef.has_value()) {
        llvm::StringRef buffer = BufferRef->getBuffer().substr(
            SourceMgr.getFileOffset(MacroCallLoc));
        if (buffer.starts_with("NS_ENUM(") ||
            buffer.starts_with("NS_OPTIONS(")) {
          // We want to use the comment on the call to NS_ENUM and NS_OPTIONS
          // macros for the types defined inside the macros, which is at the
          // expansion location.
          return MacroCallLoc;
        }
      }
    }
    return SourceMgr.getSpellingLoc(D->getBeginLoc());
  }
 
  return DeclLoc;
}
 
RawComment *ASTContext::getRawCommentForDeclNoCacheImpl(
    const Decl *D, const SourceLocation RepresentativeLocForDecl,
    const std::map<unsigned, RawComment *> &CommentsInTheFile) const {
  // If the declaration doesn't map directly to a location in a file, we
  // can't find the comment.
  if (RepresentativeLocForDecl.isInvalid() ||
      !RepresentativeLocForDecl.isFileID())
    return nullptr;
 
  // If there are no comments anywhere, we won't find anything.
  if (CommentsInTheFile.empty())
    return nullptr;
 
  // Decompose the location for the declaration and find the beginning of the
  // file buffer.
  const std::pair<FileID, unsigned> DeclLocDecomp =
      SourceMgr.getDecomposedLoc(RepresentativeLocForDecl);
 
  // Slow path.
  auto OffsetCommentBehindDecl =
      CommentsInTheFile.lower_bound(DeclLocDecomp.second);
 
  // First check whether we have a trailing comment.
  if (OffsetCommentBehindDecl != CommentsInTheFile.end()) {
    RawComment *CommentBehindDecl = OffsetCommentBehindDecl->second;
    if ((CommentBehindDecl->isDocumentation() ||
         LangOpts.CommentOpts.ParseAllComments) &&
        CommentBehindDecl->isTrailingComment() &&
        (isa<FieldDecl>(D) || isa<EnumConstantDecl>(D) || isa<VarDecl>(D) ||
         isa<ObjCMethodDecl>(D) || isa<ObjCPropertyDecl>(D))) {
 
      // Check that Doxygen trailing comment comes after the declaration, starts
      // on the same line and in the same file as the declaration.
      if (SourceMgr.getLineNumber(DeclLocDecomp.first, DeclLocDecomp.second) ==
          Comments.getCommentBeginLine(CommentBehindDecl, DeclLocDecomp.first,
                                       OffsetCommentBehindDecl->first)) {
        return CommentBehindDecl;
      }
    }
  }
 
  // The comment just after the declaration was not a trailing comment.
  // Let's look at the previous comment.
  if (OffsetCommentBehindDecl == CommentsInTheFile.begin())
    return nullptr;
 
  auto OffsetCommentBeforeDecl = --OffsetCommentBehindDecl;
  RawComment *CommentBeforeDecl = OffsetCommentBeforeDecl->second;
 
  // Check that we actually have a non-member Doxygen comment.
  if (!(CommentBeforeDecl->isDocumentation() ||
        LangOpts.CommentOpts.ParseAllComments) ||
      CommentBeforeDecl->isTrailingComment())
    return nullptr;
 
  // Decompose the end of the comment.
  const unsigned CommentEndOffset =
      Comments.getCommentEndOffset(CommentBeforeDecl);
 
  // Get the corresponding buffer.
  bool Invalid = false;
  const char *Buffer = SourceMgr.getBufferData(DeclLocDecomp.first,
                                               &Invalid).data();
  if (Invalid)
    return nullptr;
 
  // Extract text between the comment and declaration.
  StringRef Text(Buffer + CommentEndOffset,
                 DeclLocDecomp.second - CommentEndOffset);
 
  // There should be no other declarations or preprocessor directives between
  // comment and declaration.
  if (Text.find_last_of(";{}#@") != StringRef::npos)
    return nullptr;
 
  return CommentBeforeDecl;
}
 
RawComment *ASTContext::getRawCommentForDeclNoCache(const Decl *D) const {
  const SourceLocation DeclLoc = getDeclLocForCommentSearch(D, SourceMgr);
 
  // If the declaration doesn't map directly to a location in a file, we
  // can't find the comment.
  if (DeclLoc.isInvalid() || !DeclLoc.isFileID())
    return nullptr;
 
  if (ExternalSource && !CommentsLoaded) {
    ExternalSource->ReadComments();
    CommentsLoaded = true;
  }
 
  if (Comments.empty())
    return nullptr;
 
  const FileID File = SourceMgr.getDecomposedLoc(DeclLoc).first;
  if (!File.isValid()) {
    return nullptr;
  }
  const auto CommentsInThisFile = Comments.getCommentsInFile(File);
  if (!CommentsInThisFile || CommentsInThisFile->empty())
    return nullptr;
 
  return getRawCommentForDeclNoCacheImpl(D, DeclLoc, *CommentsInThisFile);
}
 
void ASTContext::addComment(const RawComment &RC) {
  assert(LangOpts.RetainCommentsFromSystemHeaders ||
         !SourceMgr.isInSystemHeader(RC.getSourceRange().getBegin()));
  Comments.addComment(RC, LangOpts.CommentOpts, BumpAlloc);
}
 
/// If we have a 'templated' declaration for a template, adjust 'D' to
/// refer to the actual template.
/// If we have an implicit instantiation, adjust 'D' to refer to template.
static const Decl &adjustDeclToTemplate(const Decl &D) {
  if (const auto *FD = dyn_cast<FunctionDecl>(&D)) {
    // Is this function declaration part of a function template?
    if (const FunctionTemplateDecl *FTD = FD->getDescribedFunctionTemplate())
      return *FTD;
 
    // Nothing to do if function is not an implicit instantiation.
    if (FD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
      return D;
 
    // Function is an implicit instantiation of a function template?
    if (const FunctionTemplateDecl *FTD = FD->getPrimaryTemplate())
      return *FTD;
 
    // Function is instantiated from a member definition of a class template?
    if (const FunctionDecl *MemberDecl =
            FD->getInstantiatedFromMemberFunction())
      return *MemberDecl;
 
    return D;
  }
  if (const auto *VD = dyn_cast<VarDecl>(&D)) {
    // Static data member is instantiated from a member definition of a class
    // template?
    if (VD->isStaticDataMember())
      if (const VarDecl *MemberDecl = VD->getInstantiatedFromStaticDataMember())
        return *MemberDecl;
 
    return D;
  }
  if (const auto *CRD = dyn_cast<CXXRecordDecl>(&D)) {
    // Is this class declaration part of a class template?
    if (const ClassTemplateDecl *CTD = CRD->getDescribedClassTemplate())
      return *CTD;
 
    // Class is an implicit instantiation of a class template or partial
    // specialization?
    if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(CRD)) {
      if (CTSD->getSpecializationKind() != TSK_ImplicitInstantiation)
        return D;
      llvm::PointerUnion<ClassTemplateDecl *,
                         ClassTemplatePartialSpecializationDecl *>
          PU = CTSD->getSpecializedTemplateOrPartial();
      return PU.is<ClassTemplateDecl *>()
                 ? *static_cast<const Decl *>(PU.get<ClassTemplateDecl *>())
                 : *static_cast<const Decl *>(
                       PU.get<ClassTemplatePartialSpecializationDecl *>());
    }
 
    // Class is instantiated from a member definition of a class template?
    if (const MemberSpecializationInfo *Info =
            CRD->getMemberSpecializationInfo())
      return *Info->getInstantiatedFrom();
 
    return D;
  }
  if (const auto *ED = dyn_cast<EnumDecl>(&D)) {
    // Enum is instantiated from a member definition of a class template?
    if (const EnumDecl *MemberDecl = ED->getInstantiatedFromMemberEnum())
      return *MemberDecl;
 
    return D;
  }
  // FIXME: Adjust alias templates?
  return D;
}
 
const RawComment *ASTContext::getRawCommentForAnyRedecl(
                                                const Decl *D,
                                                const Decl **OriginalDecl) const {
  if (!D) {
    if (OriginalDecl)
      OriginalDecl = nullptr;
    return nullptr;
  }
 
  D = &adjustDeclToTemplate(*D);
 
  // Any comment directly attached to D?
  {
    auto DeclComment = DeclRawComments.find(D);
    if (DeclComment != DeclRawComments.end()) {
      if (OriginalDecl)
        *OriginalDecl = D;
      return DeclComment->second;
    }
  }
 
  // Any comment attached to any redeclaration of D?
  const Decl *CanonicalD = D->getCanonicalDecl();
  if (!CanonicalD)
    return nullptr;
 
  {
    auto RedeclComment = RedeclChainComments.find(CanonicalD);
    if (RedeclComment != RedeclChainComments.end()) {
      if (OriginalDecl)
        *OriginalDecl = RedeclComment->second;
      auto CommentAtRedecl = DeclRawComments.find(RedeclComment->second);
      assert(CommentAtRedecl != DeclRawComments.end() &&
             "This decl is supposed to have comment attached.");
      return CommentAtRedecl->second;
    }
  }
 
  // Any redeclarations of D that we haven't checked for comments yet?
  // We can't use DenseMap::iterator directly since it'd get invalid.
  auto LastCheckedRedecl = [this, CanonicalD]() -> const Decl * {
    auto LookupRes = CommentlessRedeclChains.find(CanonicalD);
    if (LookupRes != CommentlessRedeclChains.end())
      return LookupRes->second;
    return nullptr;
  }();
 
  for (const auto Redecl : D->redecls()) {
    assert(Redecl);
    // Skip all redeclarations that have been checked previously.
    if (LastCheckedRedecl) {
      if (LastCheckedRedecl == Redecl) {
        LastCheckedRedecl = nullptr;
      }
      continue;
    }
    const RawComment *RedeclComment = getRawCommentForDeclNoCache(Redecl);
    if (RedeclComment) {
      cacheRawCommentForDecl(*Redecl, *RedeclComment);
      if (OriginalDecl)
        *OriginalDecl = Redecl;
      return RedeclComment;
    }
    CommentlessRedeclChains[CanonicalD] = Redecl;
  }
 
  if (OriginalDecl)
    *OriginalDecl = nullptr;
  return nullptr;
}
 
void ASTContext::cacheRawCommentForDecl(const Decl &OriginalD,
                                        const RawComment &Comment) const {
  assert(Comment.isDocumentation() || LangOpts.CommentOpts.ParseAllComments);
  DeclRawComments.try_emplace(&OriginalD, &Comment);
  const Decl *const CanonicalDecl = OriginalD.getCanonicalDecl();
  RedeclChainComments.try_emplace(CanonicalDecl, &OriginalD);
  CommentlessRedeclChains.erase(CanonicalDecl);
}
 
static void addRedeclaredMethods(const ObjCMethodDecl *ObjCMethod,
                   SmallVectorImpl<const NamedDecl *> &Redeclared) {
  const DeclContext *DC = ObjCMethod->getDeclContext();
  if (const auto *IMD = dyn_cast<ObjCImplDecl>(DC)) {
    const ObjCInterfaceDecl *ID = IMD->getClassInterface();
    if (!ID)
      return;
    // Add redeclared method here.
    for (const auto *Ext : ID->known_extensions()) {
      if (ObjCMethodDecl *RedeclaredMethod =
            Ext->getMethod(ObjCMethod->getSelector(),
                                  ObjCMethod->isInstanceMethod()))
        Redeclared.push_back(RedeclaredMethod);
    }
  }
}
 
void ASTContext::attachCommentsToJustParsedDecls(ArrayRef<Decl *> Decls,
                                                 const Preprocessor *PP) {
  if (Comments.empty() || Decls.empty())
    return;
 
  FileID File;
  for (Decl *D : Decls) {
    SourceLocation Loc = D->getLocation();
    if (Loc.isValid()) {
      // See if there are any new comments that are not attached to a decl.
      // The location doesn't have to be precise - we care only about the file.
      File = SourceMgr.getDecomposedLoc(Loc).first;
      break;
    }
  }
 
  if (File.isInvalid())
    return;
 
  auto CommentsInThisFile = Comments.getCommentsInFile(File);
  if (!CommentsInThisFile || CommentsInThisFile->empty() ||
      CommentsInThisFile->rbegin()->second->isAttached())
    return;
 
  // There is at least one comment not attached to a decl.
  // Maybe it should be attached to one of Decls?
  //
  // Note that this way we pick up not only comments that precede the
  // declaration, but also comments that *follow* the declaration -- thanks to
  // the lookahead in the lexer: we've consumed the semicolon and looked
  // ahead through comments.
 
  for (const Decl *D : Decls) {
    assert(D);
    if (D->isInvalidDecl())
      continue;
 
    D = &adjustDeclToTemplate(*D);
 
    const SourceLocation DeclLoc = getDeclLocForCommentSearch(D, SourceMgr);
 
    if (DeclLoc.isInvalid() || !DeclLoc.isFileID())
      continue;
 
    if (DeclRawComments.count(D) > 0)
      continue;
 
    if (RawComment *const DocComment =
            getRawCommentForDeclNoCacheImpl(D, DeclLoc, *CommentsInThisFile)) {
      cacheRawCommentForDecl(*D, *DocComment);
      comments::FullComment *FC = DocComment->parse(*this, PP, D);
      ParsedComments[D->getCanonicalDecl()] = FC;
    }
  }
}
 
comments::FullComment *ASTContext::cloneFullComment(comments::FullComment *FC,
                                                    const Decl *D) const {
  auto *ThisDeclInfo = new (*this) comments::DeclInfo;
  ThisDeclInfo->CommentDecl = D;
  ThisDeclInfo->IsFilled = false;
  ThisDeclInfo->fill();
  ThisDeclInfo->CommentDecl = FC->getDecl();
  if (!ThisDeclInfo->TemplateParameters)
    ThisDeclInfo->TemplateParameters = FC->getDeclInfo()->TemplateParameters;
  comments::FullComment *CFC =
    new (*this) comments::FullComment(FC->getBlocks(),
                                      ThisDeclInfo);
  return CFC;
}
 
comments::FullComment *ASTContext::getLocalCommentForDeclUncached(const Decl *D) const {
  const RawComment *RC = getRawCommentForDeclNoCache(D);
  return RC ? RC->parse(*this, nullptr, D) : nullptr;
}
 
comments::FullComment *ASTContext::getCommentForDecl(
                                              const Decl *D,
                                              const Preprocessor *PP) const {
  if (!D || D->isInvalidDecl())
    return nullptr;
  D = &adjustDeclToTemplate(*D);
 
  const Decl *Canonical = D->getCanonicalDecl();
  llvm::DenseMap<const Decl *, comments::FullComment *>::iterator Pos =
      ParsedComments.find(Canonical);
 
  if (Pos != ParsedComments.end()) {
    if (Canonical != D) {
      comments::FullComment *FC = Pos->second;
      comments::FullComment *CFC = cloneFullComment(FC, D);
      return CFC;
    }
    return Pos->second;
  }
 
  const Decl *OriginalDecl = nullptr;
 
  const RawComment *RC = getRawCommentForAnyRedecl(D, &OriginalDecl);
  if (!RC) {
    if (isa<ObjCMethodDecl>(D) || isa<FunctionDecl>(D)) {
      SmallVector<const NamedDecl*, 8> Overridden;
      const auto *OMD = dyn_cast<ObjCMethodDecl>(D);
      if (OMD && OMD->isPropertyAccessor())
        if (const ObjCPropertyDecl *PDecl = OMD->findPropertyDecl())
          if (comments::FullComment *FC = getCommentForDecl(PDecl, PP))
            return cloneFullComment(FC, D);
      if (OMD)
        addRedeclaredMethods(OMD, Overridden);
      getOverriddenMethods(dyn_cast<NamedDecl>(D), Overridden);
      for (unsigned i = 0, e = Overridden.size(); i < e; i++)
        if (comments::FullComment *FC = getCommentForDecl(Overridden[i], PP))
          return cloneFullComment(FC, D);
    }
    else if (const auto *TD = dyn_cast<TypedefNameDecl>(D)) {
      // Attach any tag type's documentation to its typedef if latter
      // does not have one of its own.
      QualType QT = TD->getUnderlyingType();
      if (const auto *TT = QT->getAs<TagType>())
        if (const Decl *TD = TT->getDecl())
          if (comments::FullComment *FC = getCommentForDecl(TD, PP))
            return cloneFullComment(FC, D);
    }
    else if (const auto *IC = dyn_cast<ObjCInterfaceDecl>(D)) {
      while (IC->getSuperClass()) {
        IC = IC->getSuperClass();
        if (comments::FullComment *FC = getCommentForDecl(IC, PP))
          return cloneFullComment(FC, D);
      }
    }
    else if (const auto *CD = dyn_cast<ObjCCategoryDecl>(D)) {
      if (const ObjCInterfaceDecl *IC = CD->getClassInterface())
        if (comments::FullComment *FC = getCommentForDecl(IC, PP))
          return cloneFullComment(FC, D);
    }
    else if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
      if (!(RD = RD->getDefinition()))
        return nullptr;
      // Check non-virtual bases.
      for (const auto &I : RD->bases()) {
        if (I.isVirtual() || (I.getAccessSpecifier() != AS_public))
          continue;
        QualType Ty = I.getType();
        if (Ty.isNull())
          continue;
        if (const CXXRecordDecl *NonVirtualBase = Ty->getAsCXXRecordDecl()) {
          if (!(NonVirtualBase= NonVirtualBase->getDefinition()))
            continue;
 
          if (comments::FullComment *FC = getCommentForDecl((NonVirtualBase), PP))
            return cloneFullComment(FC, D);
        }
      }
      // Check virtual bases.
      for (const auto &I : RD->vbases()) {
        if (I.getAccessSpecifier() != AS_public)
          continue;
        QualType Ty = I.getType();
        if (Ty.isNull())
          continue;
        if (const CXXRecordDecl *VirtualBase = Ty->getAsCXXRecordDecl()) {
          if (!(VirtualBase= VirtualBase->getDefinition()))
            continue;
          if (comments::FullComment *FC = getCommentForDecl((VirtualBase), PP))
            return cloneFullComment(FC, D);
        }
      }
    }
    return nullptr;
  }
 
  // If the RawComment was attached to other redeclaration of this Decl, we
  // should parse the comment in context of that other Decl.  This is important
  // because comments can contain references to parameter names which can be
  // different across redeclarations.
  if (D != OriginalDecl && OriginalDecl)
    return getCommentForDecl(OriginalDecl, PP);
 
  comments::FullComment *FC = RC->parse(*this, PP, D);
  ParsedComments[Canonical] = FC;
  return FC;
}
 
void
ASTContext::CanonicalTemplateTemplateParm::Profile(llvm::FoldingSetNodeID &ID,
                                                   const ASTContext &C,
                                               TemplateTemplateParmDecl *Parm) {
  ID.AddInteger(Parm->getDepth());
  ID.AddInteger(Parm->getPosition());
  ID.AddBoolean(Parm->isParameterPack());
 
  TemplateParameterList *Params = Parm->getTemplateParameters();
  ID.AddInteger(Params->size());
  for (TemplateParameterList::const_iterator P = Params->begin(),
                                          PEnd = Params->end();
       P != PEnd; ++P) {
    if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(*P)) {
      ID.AddInteger(0);
      ID.AddBoolean(TTP->isParameterPack());
      if (TTP->isExpandedParameterPack()) {
        ID.AddBoolean(true);
        ID.AddInteger(TTP->getNumExpansionParameters());
      } else
        ID.AddBoolean(false);
      continue;
    }
 
    if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
      ID.AddInteger(1);
      ID.AddBoolean(NTTP->isParameterPack());
      ID.AddPointer(C.getUnconstrainedType(C.getCanonicalType(NTTP->getType()))
                        .getAsOpaquePtr());
      if (NTTP->isExpandedParameterPack()) {
        ID.AddBoolean(true);
        ID.AddInteger(NTTP->getNumExpansionTypes());
        for (unsigned I = 0, N = NTTP->getNumExpansionTypes(); I != N; ++I) {
          QualType T = NTTP->getExpansionType(I);
          ID.AddPointer(T.getCanonicalType().getAsOpaquePtr());
        }
      } else
        ID.AddBoolean(false);
      continue;
    }
 
    auto *TTP = cast<TemplateTemplateParmDecl>(*P);
    ID.AddInteger(2);
    Profile(ID, C, TTP);
  }
}
 
TemplateTemplateParmDecl *
ASTContext::getCanonicalTemplateTemplateParmDecl(
                                          TemplateTemplateParmDecl *TTP) const {
  // Check if we already have a canonical template template parameter.
  llvm::FoldingSetNodeID ID;
  CanonicalTemplateTemplateParm::Profile(ID, *this, TTP);
  void *InsertPos = nullptr;
  CanonicalTemplateTemplateParm *Canonical
    = CanonTemplateTemplateParms.FindNodeOrInsertPos(ID, InsertPos);
  if (Canonical)
    return Canonical->getParam();
 
  // Build a canonical template parameter list.
  TemplateParameterList *Params = TTP->getTemplateParameters();
  SmallVector<NamedDecl *, 4> CanonParams;
  CanonParams.reserve(Params->size());
  for (TemplateParameterList::const_iterator P = Params->begin(),
                                          PEnd = Params->end();
       P != PEnd; ++P) {
    // Note that, per C++20 [temp.over.link]/6, when determining whether
    // template-parameters are equivalent, constraints are ignored.
    if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(*P)) {
      TemplateTypeParmDecl *NewTTP = TemplateTypeParmDecl::Create(
          *this, getTranslationUnitDecl(), SourceLocation(), SourceLocation(),
          TTP->getDepth(), TTP->getIndex(), nullptr, false,
          TTP->isParameterPack(), /*HasTypeConstraint=*/false,
          TTP->isExpandedParameterPack()
              ? std::optional<unsigned>(TTP->getNumExpansionParameters())
              : std::nullopt);
      CanonParams.push_back(NewTTP);
    } else if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
      QualType T = getUnconstrainedType(getCanonicalType(NTTP->getType()));
      TypeSourceInfo *TInfo = getTrivialTypeSourceInfo(T);
      NonTypeTemplateParmDecl *Param;
      if (NTTP->isExpandedParameterPack()) {
        SmallVector<QualType, 2> ExpandedTypes;
        SmallVector<TypeSourceInfo *, 2> ExpandedTInfos;
        for (unsigned I = 0, N = NTTP->getNumExpansionTypes(); I != N; ++I) {
          ExpandedTypes.push_back(getCanonicalType(NTTP->getExpansionType(I)));
          ExpandedTInfos.push_back(
                                getTrivialTypeSourceInfo(ExpandedTypes.back()));
        }
 
        Param = NonTypeTemplateParmDecl::Create(*this, getTranslationUnitDecl(),
                                                SourceLocation(),
                                                SourceLocation(),
                                                NTTP->getDepth(),
                                                NTTP->getPosition(), nullptr,
                                                T,
                                                TInfo,
                                                ExpandedTypes,
                                                ExpandedTInfos);
      } else {
        Param = NonTypeTemplateParmDecl::Create(*this, getTranslationUnitDecl(),
                                                SourceLocation(),
                                                SourceLocation(),
                                                NTTP->getDepth(),
                                                NTTP->getPosition(), nullptr,
                                                T,
                                                NTTP->isParameterPack(),
                                                TInfo);
      }
      CanonParams.push_back(Param);
    } else
      CanonParams.push_back(getCanonicalTemplateTemplateParmDecl(
                                           cast<TemplateTemplateParmDecl>(*P)));
  }
 
  TemplateTemplateParmDecl *CanonTTP = TemplateTemplateParmDecl::Create(
      *this, getTranslationUnitDecl(), SourceLocation(), TTP->getDepth(),
      TTP->getPosition(), TTP->isParameterPack(), nullptr,
      TemplateParameterList::Create(*this, SourceLocation(), SourceLocation(),
                                    CanonParams, SourceLocation(),
                                    /*RequiresClause=*/nullptr));
 
  // Get the new insert position for the node we care about.
  Canonical = CanonTemplateTemplateParms.FindNodeOrInsertPos(ID, InsertPos);
  assert(!Canonical && "Shouldn't be in the map!");
  (void)Canonical;
 
  // Create the canonical template template parameter entry.
  Canonical = new (*this) CanonicalTemplateTemplateParm(CanonTTP);
  CanonTemplateTemplateParms.InsertNode(Canonical, InsertPos);
  return CanonTTP;
}
 
TargetCXXABI::Kind ASTContext::getCXXABIKind() const {
  auto Kind = getTargetInfo().getCXXABI().getKind();
  return getLangOpts().CXXABI.value_or(Kind);
}
 
CXXABI *ASTContext::createCXXABI(const TargetInfo &T) {
  if (!LangOpts.CPlusPlus) return nullptr;
 
  switch (getCXXABIKind()) {
  case TargetCXXABI::AppleARM64:
  case TargetCXXABI::Fuchsia:
  case TargetCXXABI::GenericARM: // Same as Itanium at this level
  case TargetCXXABI::iOS:
  case TargetCXXABI::WatchOS:
  case TargetCXXABI::GenericAArch64:
  case TargetCXXABI::GenericMIPS:
  case TargetCXXABI::GenericItanium:
  case TargetCXXABI::WebAssembly:
  case TargetCXXABI::XL:
    return CreateItaniumCXXABI(*this);
  case TargetCXXABI::Microsoft:
    return CreateMicrosoftCXXABI(*this);
  }
  llvm_unreachable("Invalid CXXABI type!");
}
 
interp::Context &ASTContext::getInterpContext() {
  if (!InterpContext) {
    InterpContext.reset(new interp::Context(*this));
  }
  return *InterpContext.get();
}
 
ParentMapContext &ASTContext::getParentMapContext() {
  if (!ParentMapCtx)
    ParentMapCtx.reset(new ParentMapContext(*this));
  return *ParentMapCtx.get();
}
 
static bool isAddrSpaceMapManglingEnabled(const TargetInfo &TI,
                                          const LangOptions &LangOpts) {
  switch (LangOpts.getAddressSpaceMapMangling()) {
  case LangOptions::ASMM_Target:
    return TI.useAddressSpaceMapMangling();
  case LangOptions::ASMM_On:
    return true;
  case LangOptions::ASMM_Off:
    return false;
  }
  llvm_unreachable("getAddressSpaceMapMangling() doesn't cover anything.");
}
 
ASTContext::ASTContext(LangOptions &LOpts, SourceManager &SM,
                       IdentifierTable &idents, SelectorTable &sels,
                       Builtin::Context &builtins, TranslationUnitKind TUKind)
    : ConstantArrayTypes(this_(), ConstantArrayTypesLog2InitSize),
      FunctionProtoTypes(this_(), FunctionProtoTypesLog2InitSize),
      TemplateSpecializationTypes(this_()),
      DependentTemplateSpecializationTypes(this_()), AutoTypes(this_()),
      SubstTemplateTemplateParmPacks(this_()),
      CanonTemplateTemplateParms(this_()), SourceMgr(SM), LangOpts(LOpts),
      NoSanitizeL(new NoSanitizeList(LangOpts.NoSanitizeFiles, SM)),
      XRayFilter(new XRayFunctionFilter(LangOpts.XRayAlwaysInstrumentFiles,
                                        LangOpts.XRayNeverInstrumentFiles,
                                        LangOpts.XRayAttrListFiles, SM)),
      ProfList(new ProfileList(LangOpts.ProfileListFiles, SM)),
      PrintingPolicy(LOpts), Idents(idents), Selectors(sels),
      BuiltinInfo(builtins), TUKind(TUKind), DeclarationNames(*this),
      Comments(SM), CommentCommandTraits(BumpAlloc, LOpts.CommentOpts),
      CompCategories(this_()), LastSDM(nullptr, 0) {
  addTranslationUnitDecl();
}
 
void ASTContext::cleanup() {
  // Release the DenseMaps associated with DeclContext objects.
  // FIXME: Is this the ideal solution?
  ReleaseDeclContextMaps();
 
  // Call all of the deallocation functions on all of their targets.
  for (auto &Pair : Deallocations)
    (Pair.first)(Pair.second);
  Deallocations.clear();
 
  // ASTRecordLayout objects in ASTRecordLayouts must always be destroyed
  // because they can contain DenseMaps.
  for (llvm::DenseMap<const ObjCContainerDecl*,
       const ASTRecordLayout*>::iterator
       I = ObjCLayouts.begin(), E = ObjCLayouts.end(); I != E; )
    // Increment in loop to prevent using deallocated memory.
    if (auto *R = const_cast<ASTRecordLayout *>((I++)->second))
      R->Destroy(*this);
  ObjCLayouts.clear();
 
  for (llvm::DenseMap<const RecordDecl*, const ASTRecordLayout*>::iterator
       I = ASTRecordLayouts.begin(), E = ASTRecordLayouts.end(); I != E; ) {
    // Increment in loop to prevent using deallocated memory.
    if (auto *R = const_cast<ASTRecordLayout *>((I++)->second))
      R->Destroy(*this);
  }
  ASTRecordLayouts.clear();
 
  for (llvm::DenseMap<const Decl*, AttrVec*>::iterator A = DeclAttrs.begin(),
                                                    AEnd = DeclAttrs.end();
       A != AEnd; ++A)
    A->second->~AttrVec();
  DeclAttrs.clear();
 
  for (const auto &Value : ModuleInitializers)
    Value.second->~PerModuleInitializers();
  ModuleInitializers.clear();
}
 
ASTContext::~ASTContext() { cleanup(); }
 
void ASTContext::setTraversalScope(const std::vector<Decl *> &TopLevelDecls) {
  TraversalScope = TopLevelDecls;
  getParentMapContext().clear();
}
 
void ASTContext::AddDeallocation(void (*Callback)(void *), void *Data) const {
  Deallocations.push_back({Callback, Data});
}
 
void
ASTContext::setExternalSource(IntrusiveRefCntPtr<ExternalASTSource> Source) {
  ExternalSource = std::move(Source);
}
 
void ASTContext::PrintStats() const {
  llvm::errs() << "\n*** AST Context Stats:\n";
  llvm::errs() << "  " << Types.size() << " types total.\n";
 
  unsigned counts[] = {
#define TYPE(Name, Parent) 0,
#define ABSTRACT_TYPE(Name, Parent)
#include "clang/AST/TypeNodes.inc"
    0 // Extra
  };
 
  for (unsigned i = 0, e = Types.size(); i != e; ++i) {
    Type *T = Types[i];
    counts[(unsigned)T->getTypeClass()]++;
  }
 
  unsigned Idx = 0;
  unsigned TotalBytes = 0;
#define TYPE(Name, Parent)                                              \
  if (counts[Idx])                                                      \
    llvm::errs() << "    " << counts[Idx] << " " << #Name               \
                 << " types, " << sizeof(Name##Type) << " each "        \
                 << "(" << counts[Idx] * sizeof(Name##Type)             \
                 << " bytes)\n";                                        \
  TotalBytes += counts[Idx] * sizeof(Name##Type);                       \
  ++Idx;
#define ABSTRACT_TYPE(Name, Parent)
#include "clang/AST/TypeNodes.inc"
 
  llvm::errs() << "Total bytes = " << TotalBytes << "\n";
 
  // Implicit special member functions.
  llvm::errs() << NumImplicitDefaultConstructorsDeclared << "/"
               << NumImplicitDefaultConstructors
               << " implicit default constructors created\n";
  llvm::errs() << NumImplicitCopyConstructorsDeclared << "/"
               << NumImplicitCopyConstructors
               << " implicit copy constructors created\n";
  if (getLangOpts().CPlusPlus)
    llvm::errs() << NumImplicitMoveConstructorsDeclared << "/"
                 << NumImplicitMoveConstructors
                 << " implicit move constructors created\n";
  llvm::errs() << NumImplicitCopyAssignmentOperatorsDeclared << "/"
               << NumImplicitCopyAssignmentOperators
               << " implicit copy assignment operators created\n";
  if (getLangOpts().CPlusPlus)
    llvm::errs() << NumImplicitMoveAssignmentOperatorsDeclared << "/"
                 << NumImplicitMoveAssignmentOperators
                 << " implicit move assignment operators created\n";
  llvm::errs() << NumImplicitDestructorsDeclared << "/"
               << NumImplicitDestructors
               << " implicit destructors created\n";
 
  if (ExternalSource) {
    llvm::errs() << "\n";
    ExternalSource->PrintStats();
  }
 
  BumpAlloc.PrintStats();
}
 
void ASTContext::mergeDefinitionIntoModule(NamedDecl *ND, Module *M,
                                           bool NotifyListeners) {
  if (NotifyListeners)
    if (auto *Listener = getASTMutationListener())
      Listener->RedefinedHiddenDefinition(ND, M);
 
  MergedDefModules[cast<NamedDecl>(ND->getCanonicalDecl())].push_back(M);
}
 
void ASTContext::deduplicateMergedDefinitonsFor(NamedDecl *ND) {
  auto It = MergedDefModules.find(cast<NamedDecl>(ND->getCanonicalDecl()));
  if (It == MergedDefModules.end())
    return;
 
  auto &Merged = It->second;
  llvm::DenseSet<Module*> Found;
  for (Module *&M : Merged)
    if (!Found.insert(M).second)
      M = nullptr;
  llvm::erase_value(Merged, nullptr);
}
 
ArrayRef<Module *>
ASTContext::getModulesWithMergedDefinition(const NamedDecl *Def) {
  auto MergedIt =
      MergedDefModules.find(cast<NamedDecl>(Def->getCanonicalDecl()));
  if (MergedIt == MergedDefModules.end())
    return std::nullopt;
  return MergedIt->second;
}
 
void ASTContext::PerModuleInitializers::resolve(ASTContext &Ctx) {
  if (LazyInitializers.empty())
    return;
 
  auto *Source = Ctx.getExternalSource();
  assert(Source && "lazy initializers but no external source");
 
  auto LazyInits = std::move(LazyInitializers);
  LazyInitializers.clear();
 
  for (auto ID : LazyInits)
    Initializers.push_back(Source->GetExternalDecl(ID));
 
  assert(LazyInitializers.empty() &&
         "GetExternalDecl for lazy module initializer added more inits");
}
 
void ASTContext::addModuleInitializer(Module *M, Decl *D) {
  // One special case: if we add a module initializer that imports another
  // module, and that module's only initializer is an ImportDecl, simplify.
  if (const auto *ID = dyn_cast<ImportDecl>(D)) {
    auto It = ModuleInitializers.find(ID->getImportedModule());
 
    // Maybe the ImportDecl does nothing at all. (Common case.)
    if (It == ModuleInitializers.end())
      return;
 
    // Maybe the ImportDecl only imports another ImportDecl.
    auto &Imported = *It->second;
    if (Imported.Initializers.size() + Imported.LazyInitializers.size() == 1) {
      Imported.resolve(*this);
      auto *OnlyDecl = Imported.Initializers.front();
      if (isa<ImportDecl>(OnlyDecl))
        D = OnlyDecl;
    }
  }
 
  auto *&Inits = ModuleInitializers[M];
  if (!Inits)
    Inits = new (*this) PerModuleInitializers;
  Inits->Initializers.push_back(D);
}
 
void ASTContext::addLazyModuleInitializers(Module *M, ArrayRef<uint32_t> IDs) {
  auto *&Inits = ModuleInitializers[M];
  if (!Inits)
    Inits = new (*this) PerModuleInitializers;
  Inits->LazyInitializers.insert(Inits->LazyInitializers.end(),
                                 IDs.begin(), IDs.end());
}
 
ArrayRef<Decl *> ASTContext::getModuleInitializers(Module *M) {
  auto It = ModuleInitializers.find(M);
  if (It == ModuleInitializers.end())
    return std::nullopt;
 
  auto *Inits = It->second;
  Inits->resolve(*this);
  return Inits->Initializers;
}
 
void ASTContext::setCurrentNamedModule(Module *M) {
  assert(M->isModulePurview());
  assert(!CurrentCXXNamedModule &&
         "We should set named module for ASTContext for only once");
  CurrentCXXNamedModule = M;
}
 
ExternCContextDecl *ASTContext::getExternCContextDecl() const {
  if (!ExternCContext)
    ExternCContext = ExternCContextDecl::Create(*this, getTranslationUnitDecl());
 
  return ExternCContext;
}
 
BuiltinTemplateDecl *
ASTContext::buildBuiltinTemplateDecl(BuiltinTemplateKind BTK,
                                     const IdentifierInfo *II) const {
  auto *BuiltinTemplate =
      BuiltinTemplateDecl::Create(*this, getTranslationUnitDecl(), II, BTK);
  BuiltinTemplate->setImplicit();
  getTranslationUnitDecl()->addDecl(BuiltinTemplate);
 
  return BuiltinTemplate;
}
 
BuiltinTemplateDecl *
ASTContext::getMakeIntegerSeqDecl() const {
  if (!MakeIntegerSeqDecl)
    MakeIntegerSeqDecl = buildBuiltinTemplateDecl(BTK__make_integer_seq,
                                                  getMakeIntegerSeqName());
  return MakeIntegerSeqDecl;
}
 
BuiltinTemplateDecl *
ASTContext::getTypePackElementDecl() const {
  if (!TypePackElementDecl)
    TypePackElementDecl = buildBuiltinTemplateDecl(BTK__type_pack_element,
                                                   getTypePackElementName());
  return TypePackElementDecl;
}
 
RecordDecl *ASTContext::buildImplicitRecord(StringRef Name,
                                            RecordDecl::TagKind TK) const {
  SourceLocation Loc;
  RecordDecl *NewDecl;
  if (getLangOpts().CPlusPlus)
    NewDecl = CXXRecordDecl::Create(*this, TK, getTranslationUnitDecl(), Loc,
                                    Loc, &Idents.get(Name));
  else
    NewDecl = RecordDecl::Create(*this, TK, getTranslationUnitDecl(), Loc, Loc,
                                 &Idents.get(Name));
  NewDecl->setImplicit();
  NewDecl->addAttr(TypeVisibilityAttr::CreateImplicit(
      const_cast<ASTContext &>(*this), TypeVisibilityAttr::Default));
  return NewDecl;
}
 
TypedefDecl *ASTContext::buildImplicitTypedef(QualType T,
                                              StringRef Name) const {
  TypeSourceInfo *TInfo = getTrivialTypeSourceInfo(T);
  TypedefDecl *NewDecl = TypedefDecl::Create(
      const_cast<ASTContext &>(*this), getTranslationUnitDecl(),
      SourceLocation(), SourceLocation(), &Idents.get(Name), TInfo);
  NewDecl->setImplicit();
  return NewDecl;
}
 
TypedefDecl *ASTContext::getInt128Decl() const {
  if (!Int128Decl)
    Int128Decl = buildImplicitTypedef(Int128Ty, "__int128_t");
  return Int128Decl;
}
 
TypedefDecl *ASTContext::getUInt128Decl() const {
  if (!UInt128Decl)
    UInt128Decl = buildImplicitTypedef(UnsignedInt128Ty, "__uint128_t");
  return UInt128Decl;
}
 
void ASTContext::InitBuiltinType(CanQualType &R, BuiltinType::Kind K) {
  auto *Ty = new (*this, TypeAlignment) BuiltinType(K);
  R = CanQualType::CreateUnsafe(QualType(Ty, 0));
  Types.push_back(Ty);
}
 
void ASTContext::InitBuiltinTypes(const TargetInfo &Target,
                                  const TargetInfo *AuxTarget) {
  assert((!this->Target || this->Target == &Target) &&
         "Incorrect target reinitialization");
  assert(VoidTy.isNull() && "Context reinitialized?");
 
  this->Target = &Target;
  this->AuxTarget = AuxTarget;
 
  ABI.reset(createCXXABI(Target));
  AddrSpaceMapMangling = isAddrSpaceMapManglingEnabled(Target, LangOpts);
 
  // C99 6.2.5p19.
  InitBuiltinType(VoidTy,              BuiltinType::Void);
 
  // C99 6.2.5p2.
  InitBuiltinType(BoolTy,              BuiltinType::Bool);
  // C99 6.2.5p3.
  if (LangOpts.CharIsSigned)
    InitBuiltinType(CharTy,            BuiltinType::Char_S);
  else
    InitBuiltinType(CharTy,            BuiltinType::Char_U);
  // C99 6.2.5p4.
  InitBuiltinType(SignedCharTy,        BuiltinType::SChar);
  InitBuiltinType(ShortTy,             BuiltinType::Short);
  InitBuiltinType(IntTy,               BuiltinType::Int);
  InitBuiltinType(LongTy,              BuiltinType::Long);
  InitBuiltinType(LongLongTy,          BuiltinType::LongLong);
 
  // C99 6.2.5p6.
  InitBuiltinType(UnsignedCharTy,      BuiltinType::UChar);
  InitBuiltinType(UnsignedShortTy,     BuiltinType::UShort);
  InitBuiltinType(UnsignedIntTy,       BuiltinType::UInt);
  InitBuiltinType(UnsignedLongTy,      BuiltinType::ULong);
  InitBuiltinType(UnsignedLongLongTy,  BuiltinType::ULongLong);
 
  // C99 6.2.5p10.
  InitBuiltinType(FloatTy,             BuiltinType::Float);
  InitBuiltinType(DoubleTy,            BuiltinType::Double);
  InitBuiltinType(LongDoubleTy,        BuiltinType::LongDouble);
 
  // GNU extension, __float128 for IEEE quadruple precision
  InitBuiltinType(Float128Ty,          BuiltinType::Float128);
 
  // __ibm128 for IBM extended precision
  InitBuiltinType(Ibm128Ty, BuiltinType::Ibm128);
 
  // C11 extension ISO/IEC TS 18661-3
  InitBuiltinType(Float16Ty,           BuiltinType::Float16);
 
  // ISO/IEC JTC1 SC22 WG14 N1169 Extension
  InitBuiltinType(ShortAccumTy,            BuiltinType::ShortAccum);
  InitBuiltinType(AccumTy,                 BuiltinType::Accum);
  InitBuiltinType(LongAccumTy,             BuiltinType::LongAccum);
  InitBuiltinType(UnsignedShortAccumTy,    BuiltinType::UShortAccum);
  InitBuiltinType(UnsignedAccumTy,         BuiltinType::UAccum);
  InitBuiltinType(UnsignedLongAccumTy,     BuiltinType::ULongAccum);
  InitBuiltinType(ShortFractTy,            BuiltinType::ShortFract);
  InitBuiltinType(FractTy,                 BuiltinType::Fract);
  InitBuiltinType(LongFractTy,             BuiltinType::LongFract);
  InitBuiltinType(UnsignedShortFractTy,    BuiltinType::UShortFract);
  InitBuiltinType(UnsignedFractTy,         BuiltinType::UFract);
  InitBuiltinType(UnsignedLongFractTy,     BuiltinType::ULongFract);
  InitBuiltinType(SatShortAccumTy,         BuiltinType::SatShortAccum);
  InitBuiltinType(SatAccumTy,              BuiltinType::SatAccum);
  InitBuiltinType(SatLongAccumTy,          BuiltinType::SatLongAccum);
  InitBuiltinType(SatUnsignedShortAccumTy, BuiltinType::SatUShortAccum);
  InitBuiltinType(SatUnsignedAccumTy,      BuiltinType::SatUAccum);
  InitBuiltinType(SatUnsignedLongAccumTy,  BuiltinType::SatULongAccum);
  InitBuiltinType(SatShortFractTy,         BuiltinType::SatShortFract);
  InitBuiltinType(SatFractTy,              BuiltinType::SatFract);
  InitBuiltinType(SatLongFractTy,          BuiltinType::SatLongFract);
  InitBuiltinType(SatUnsignedShortFractTy, BuiltinType::SatUShortFract);
  InitBuiltinType(SatUnsignedFractTy,      BuiltinType::SatUFract);
  InitBuiltinType(SatUnsignedLongFractTy,  BuiltinType::SatULongFract);
 
  // GNU extension, 128-bit integers.
  InitBuiltinType(Int128Ty,            BuiltinType::Int128);
  InitBuiltinType(UnsignedInt128Ty,    BuiltinType::UInt128);
 
  // C++ 3.9.1p5
  if (TargetInfo::isTypeSigned(Target.getWCharType()))
    InitBuiltinType(WCharTy,           BuiltinType::WChar_S);
  else  // -fshort-wchar makes wchar_t be unsigned.
    InitBuiltinType(WCharTy,           BuiltinType::WChar_U);
  if (LangOpts.CPlusPlus && LangOpts.WChar)
    WideCharTy = WCharTy;
  else {
    // C99 (or C++ using -fno-wchar).
    WideCharTy = getFromTargetType(Target.getWCharType());
  }
 
  WIntTy = getFromTargetType(Target.getWIntType());
 
  // C++20 (proposed)
  InitBuiltinType(Char8Ty,              BuiltinType::Char8);
 
  if (LangOpts.CPlusPlus) // C++0x 3.9.1p5, extension for C++
    InitBuiltinType(Char16Ty,           BuiltinType::Char16);
  else // C99
    Char16Ty = getFromTargetType(Target.getChar16Type());
 
  if (LangOpts.CPlusPlus) // C++0x 3.9.1p5, extension for C++
    InitBuiltinType(Char32Ty,           BuiltinType::Char32);
  else // C99
    Char32Ty = getFromTargetType(Target.getChar32Type());
 
  // Placeholder type for type-dependent expressions whose type is
  // completely unknown. No code should ever check a type against
  // DependentTy and users should never see it; however, it is here to
  // help diagnose failures to properly check for type-dependent
  // expressions.
  InitBuiltinType(DependentTy,         BuiltinType::Dependent);
 
  // Placeholder type for functions.
  InitBuiltinType(OverloadTy,          BuiltinType::Overload);
 
  // Placeholder type for bound members.
  InitBuiltinType(BoundMemberTy,       BuiltinType::BoundMember);
 
  // Placeholder type for pseudo-objects.
  InitBuiltinType(PseudoObjectTy,      BuiltinType::PseudoObject);
 
  // "any" type; useful for debugger-like clients.
  InitBuiltinType(UnknownAnyTy,        BuiltinType::UnknownAny);
 
  // Placeholder type for unbridged ARC casts.
  InitBuiltinType(ARCUnbridgedCastTy,  BuiltinType::ARCUnbridgedCast);
 
  // Placeholder type for builtin functions.
  InitBuiltinType(BuiltinFnTy,  BuiltinType::BuiltinFn);
 
  // Placeholder type for OMP array sections.
  if (LangOpts.OpenMP) {
    InitBuiltinType(OMPArraySectionTy, BuiltinType::OMPArraySection);
    InitBuiltinType(OMPArrayShapingTy, BuiltinType::OMPArrayShaping);
    InitBuiltinType(OMPIteratorTy, BuiltinType::OMPIterator);
  }
  if (LangOpts.MatrixTypes)
    InitBuiltinType(IncompleteMatrixIdxTy, BuiltinType::IncompleteMatrixIdx);
 
  // Builtin types for 'id', 'Class', and 'SEL'.
  InitBuiltinType(ObjCBuiltinIdTy, BuiltinType::ObjCId);
  InitBuiltinType(ObjCBuiltinClassTy, BuiltinType::ObjCClass);
  InitBuiltinType(ObjCBuiltinSelTy, BuiltinType::ObjCSel);
 
  if (LangOpts.OpenCL) {
#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
    InitBuiltinType(SingletonId, BuiltinType::Id);
#include "clang/Basic/OpenCLImageTypes.def"
 
    InitBuiltinType(OCLSamplerTy, BuiltinType::OCLSampler);
    InitBuiltinType(OCLEventTy, BuiltinType::OCLEvent);
    InitBuiltinType(OCLClkEventTy, BuiltinType::OCLClkEvent);
    InitBuiltinType(OCLQueueTy, BuiltinType::OCLQueue);
    InitBuiltinType(OCLReserveIDTy, BuiltinType::OCLReserveID);
 
#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
    InitBuiltinType(Id##Ty, BuiltinType::Id);
#include "clang/Basic/OpenCLExtensionTypes.def"
  }
 
  if (Target.hasAArch64SVETypes()) {
#define SVE_TYPE(Name, Id, SingletonId) \
    InitBuiltinType(SingletonId, BuiltinType::Id);
#include "clang/Basic/AArch64SVEACLETypes.def"
  }
 
  if (Target.getTriple().isPPC64()) {
#define PPC_VECTOR_MMA_TYPE(Name, Id, Size) \
      InitBuiltinType(Id##Ty, BuiltinType::Id);
#include "clang/Basic/PPCTypes.def"
#define PPC_VECTOR_VSX_TYPE(Name, Id, Size) \
    InitBuiltinType(Id##Ty, BuiltinType::Id);
#include "clang/Basic/PPCTypes.def"
  }
 
  if (Target.hasRISCVVTypes()) {
#define RVV_TYPE(Name, Id, SingletonId)                                        \
  InitBuiltinType(SingletonId, BuiltinType::Id);
#include "clang/Basic/RISCVVTypes.def"
  }
 
  if (Target.getTriple().isWasm() && Target.hasFeature("reference-types")) {
#define WASM_TYPE(Name, Id, SingletonId)                                       \
  InitBuiltinType(SingletonId, BuiltinType::Id);
#include "clang/Basic/WebAssemblyReferenceTypes.def"
  }
 
  // Builtin type for __objc_yes and __objc_no
  ObjCBuiltinBoolTy = (Target.useSignedCharForObjCBool() ?
                       SignedCharTy : BoolTy);
 
  ObjCConstantStringType = QualType();
 
  ObjCSuperType = QualType();
 
  // void * type
  if (LangOpts.OpenCLGenericAddressSpace) {
    auto Q = VoidTy.getQualifiers();
    Q.setAddressSpace(LangAS::opencl_generic);
    VoidPtrTy = getPointerType(getCanonicalType(
        getQualifiedType(VoidTy.getUnqualifiedType(), Q)));
  } else {
    VoidPtrTy = getPointerType(VoidTy);
  }
 
  // nullptr type (C++0x 2.14.7)
  InitBuiltinType(NullPtrTy,           BuiltinType::NullPtr);
 
  // half type (OpenCL 6.1.1.1) / ARM NEON __fp16
  InitBuiltinType(HalfTy, BuiltinType::Half);
 
  InitBuiltinType(BFloat16Ty, BuiltinType::BFloat16);
 
  // Builtin type used to help define __builtin_va_list.
  VaListTagDecl = nullptr;
 
  // MSVC predeclares struct _GUID, and we need it to create MSGuidDecls.
  if (LangOpts.MicrosoftExt || LangOpts.Borland) {
    MSGuidTagDecl = buildImplicitRecord("_GUID");
    getTranslationUnitDecl()->addDecl(MSGuidTagDecl);
  }
}
 
DiagnosticsEngine &ASTContext::getDiagnostics() const {
  return SourceMgr.getDiagnostics();
}
 
AttrVec& ASTContext::getDeclAttrs(const Decl *D) {
  AttrVec *&Result = DeclAttrs[D];
  if (!Result) {
    void *Mem = Allocate(sizeof(AttrVec));
    Result = new (Mem) AttrVec;
  }
 
  return *Result;
}
 
/// Erase the attributes corresponding to the given declaration.
void ASTContext::eraseDeclAttrs(const Decl *D) {
  llvm::DenseMap<const Decl*, AttrVec*>::iterator Pos = DeclAttrs.find(D);
  if (Pos != DeclAttrs.end()) {
    Pos->second->~AttrVec();
    DeclAttrs.erase(Pos);
  }
}
 
// FIXME: Remove ?
MemberSpecializationInfo *
ASTContext::getInstantiatedFromStaticDataMember(const VarDecl *Var) {
  assert(Var->isStaticDataMember() && "Not a static data member");
  return getTemplateOrSpecializationInfo(Var)
      .dyn_cast<MemberSpecializationInfo *>();
}
 
ASTContext::TemplateOrSpecializationInfo
ASTContext::getTemplateOrSpecializationInfo(const VarDecl *Var) {
  llvm::DenseMap<const VarDecl *, TemplateOrSpecializationInfo>::iterator Pos =
      TemplateOrInstantiation.find(Var);
  if (Pos == TemplateOrInstantiation.end())
    return {};
 
  return Pos->second;
}
 
void
ASTContext::setInstantiatedFromStaticDataMember(VarDecl *Inst, VarDecl *Tmpl,
                                                TemplateSpecializationKind TSK,
                                          SourceLocation PointOfInstantiation) {
  assert(Inst->isStaticDataMember() && "Not a static data member");
  assert(Tmpl->isStaticDataMember() && "Not a static data member");
  setTemplateOrSpecializationInfo(Inst, new (*this) MemberSpecializationInfo(
                                            Tmpl, TSK, PointOfInstantiation));
}
 
void
ASTContext::setTemplateOrSpecializationInfo(VarDecl *Inst,
                                            TemplateOrSpecializationInfo TSI) {
  assert(!TemplateOrInstantiation[Inst] &&
         "Already noted what the variable was instantiated from");
  TemplateOrInstantiation[Inst] = TSI;
}
 
NamedDecl *
ASTContext::getInstantiatedFromUsingDecl(NamedDecl *UUD) {
  auto Pos = InstantiatedFromUsingDecl.find(UUD);
  if (Pos == InstantiatedFromUsingDecl.end())
    return nullptr;
 
  return Pos->second;
}
 
void
ASTContext::setInstantiatedFromUsingDecl(NamedDecl *Inst, NamedDecl *Pattern) {
  assert((isa<UsingDecl>(Pattern) ||
          isa<UnresolvedUsingValueDecl>(Pattern) ||
          isa<UnresolvedUsingTypenameDecl>(Pattern)) &&
         "pattern decl is not a using decl");
  assert((isa<UsingDecl>(Inst) ||
          isa<UnresolvedUsingValueDecl>(Inst) ||
          isa<UnresolvedUsingTypenameDecl>(Inst)) &&
         "instantiation did not produce a using decl");
  assert(!InstantiatedFromUsingDecl[Inst] && "pattern already exists");
  InstantiatedFromUsingDecl[Inst] = Pattern;
}
 
UsingEnumDecl *
ASTContext::getInstantiatedFromUsingEnumDecl(UsingEnumDecl *UUD) {
  auto Pos = InstantiatedFromUsingEnumDecl.find(UUD);
  if (Pos == InstantiatedFromUsingEnumDecl.end())
    return nullptr;
 
  return Pos->second;
}
 
void ASTContext::setInstantiatedFromUsingEnumDecl(UsingEnumDecl *Inst,
                                                  UsingEnumDecl *Pattern) {
  assert(!InstantiatedFromUsingEnumDecl[Inst] && "pattern already exists");
  InstantiatedFromUsingEnumDecl[Inst] = Pattern;
}
 
UsingShadowDecl *
ASTContext::getInstantiatedFromUsingShadowDecl(UsingShadowDecl *Inst) {
  llvm::DenseMap<UsingShadowDecl*, UsingShadowDecl*>::const_iterator Pos
    = InstantiatedFromUsingShadowDecl.find(Inst);
  if (Pos == InstantiatedFromUsingShadowDecl.end())
    return nullptr;
 
  return Pos->second;
}
 
void
ASTContext::setInstantiatedFromUsingShadowDecl(UsingShadowDecl *Inst,
                                               UsingShadowDecl *Pattern) {
  assert(!InstantiatedFromUsingShadowDecl[Inst] && "pattern already exists");
  InstantiatedFromUsingShadowDecl[Inst] = Pattern;
}
 
FieldDecl *ASTContext::getInstantiatedFromUnnamedFieldDecl(FieldDecl *Field) {
  llvm::DenseMap<FieldDecl *, FieldDecl *>::iterator Pos
    = InstantiatedFromUnnamedFieldDecl.find(Field);
  if (Pos == InstantiatedFromUnnamedFieldDecl.end())
    return nullptr;
 
  return Pos->second;
}
 
void ASTContext::setInstantiatedFromUnnamedFieldDecl(FieldDecl *Inst,
                                                     FieldDecl *Tmpl) {
  assert(!Inst->getDeclName() && "Instantiated field decl is not unnamed");
  assert(!Tmpl->getDeclName() && "Template field decl is not unnamed");
  assert(!InstantiatedFromUnnamedFieldDecl[Inst] &&
         "Already noted what unnamed field was instantiated from");
 
  InstantiatedFromUnnamedFieldDecl[Inst] = Tmpl;
}
 
ASTContext::overridden_cxx_method_iterator
ASTContext::overridden_methods_begin(const CXXMethodDecl *Method) const {
  return overridden_methods(Method).begin();
}
 
ASTContext::overridden_cxx_method_iterator
ASTContext::overridden_methods_end(const CXXMethodDecl *Method) const {
  return overridden_methods(Method).end();
}
 
unsigned
ASTContext::overridden_methods_size(const CXXMethodDecl *Method) const {
  auto Range = overridden_methods(Method);
  return Range.end() - Range.begin();
}
 
ASTContext::overridden_method_range
ASTContext::overridden_methods(const CXXMethodDecl *Method) const {
  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
      OverriddenMethods.find(Method->getCanonicalDecl());
  if (Pos == OverriddenMethods.end())
    return overridden_method_range(nullptr, nullptr);
  return overridden_method_range(Pos->second.begin(), Pos->second.end());
}
 
void ASTContext::addOverriddenMethod(const CXXMethodDecl *Method,
                                     const CXXMethodDecl *Overridden) {
  assert(Method->isCanonicalDecl() && Overridden->isCanonicalDecl());
  OverriddenMethods[Method].push_back(Overridden);
}
 
void ASTContext::getOverriddenMethods(
                      const NamedDecl *D,
                      SmallVectorImpl<const NamedDecl *> &Overridden) const {
  assert(D);
 
  if (const auto *CXXMethod = dyn_cast<CXXMethodDecl>(D)) {
    Overridden.append(overridden_methods_begin(CXXMethod),
                      overridden_methods_end(CXXMethod));
    return;
  }
 
  const auto *Method = dyn_cast<ObjCMethodDecl>(D);
  if (!Method)
    return;
 
  SmallVector<const ObjCMethodDecl *, 8> OverDecls;
  Method->getOverriddenMethods(OverDecls);
  Overridden.append(OverDecls.begin(), OverDecls.end());
}
 
void ASTContext::addedLocalImportDecl(ImportDecl *Import) {
  assert(!Import->getNextLocalImport() &&
         "Import declaration already in the chain");
  assert(!Import->isFromASTFile() && "Non-local import declaration");
  if (!FirstLocalImport) {
    FirstLocalImport = Import;
    LastLocalImport = Import;
    return;
  }
 
  LastLocalImport->setNextLocalImport(Import);
  LastLocalImport = Import;
}
 
//===----------------------------------------------------------------------===//
//                         Type Sizing and Analysis
//===----------------------------------------------------------------------===//
 
/// getFloatTypeSemantics - Return the APFloat 'semantics' for the specified
/// scalar floating point type.
const llvm::fltSemantics &ASTContext::getFloatTypeSemantics(QualType T) const {
  switch (T->castAs<BuiltinType>()->getKind()) {
  default:
    llvm_unreachable("Not a floating point type!");
  case BuiltinType::BFloat16:
    return Target->getBFloat16Format();
  case BuiltinType::Float16:
    return Target->getHalfFormat();
  case BuiltinType::Half:
    // For HLSL, when the native half type is disabled, half will be treat as
    // float.
    if (getLangOpts().HLSL)
      if (getLangOpts().NativeHalfType)
        return Target->getHalfFormat();
      else
        return Target->getFloatFormat();
    else
      return Target->getHalfFormat();
  case BuiltinType::Float:      return Target->getFloatFormat();
  case BuiltinType::Double:     return Target->getDoubleFormat();
  case BuiltinType::Ibm128:
    return Target->getIbm128Format();
  case BuiltinType::LongDouble:
    if (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice)
      return AuxTarget->getLongDoubleFormat();
    return Target->getLongDoubleFormat();
  case BuiltinType::Float128:
    if (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice)
      return AuxTarget->getFloat128Format();
    return Target->getFloat128Format();
  }
}
 
CharUnits ASTContext::getDeclAlign(const Decl *D, bool ForAlignof) const {
  unsigned Align = Target->getCharWidth();
 
  bool UseAlignAttrOnly = false;
  if (unsigned AlignFromAttr = D->getMaxAlignment()) {
    Align = AlignFromAttr;
 
    // __attribute__((aligned)) can increase or decrease alignment
    // *except* on a struct or struct member, where it only increases
    // alignment unless 'packed' is also specified.
    //
    // It is an error for alignas to decrease alignment, so we can
    // ignore that possibility;  Sema should diagnose it.
    if (isa<FieldDecl>(D)) {
      UseAlignAttrOnly = D->hasAttr<PackedAttr>() ||
        cast<FieldDecl>(D)->getParent()->hasAttr<PackedAttr>();
    } else {
      UseAlignAttrOnly = true;
    }
  }
  else if (isa<FieldDecl>(D))
      UseAlignAttrOnly =
        D->hasAttr<PackedAttr>() ||
        cast<FieldDecl>(D)->getParent()->hasAttr<PackedAttr>();
 
  // If we're using the align attribute only, just ignore everything
  // else about the declaration and its type.
  if (UseAlignAttrOnly) {
    // do nothing
  } else if (const auto *VD = dyn_cast<ValueDecl>(D)) {
    QualType T = VD->getType();
    if (const auto *RT = T->getAs<ReferenceType>()) {
      if (ForAlignof)
        T = RT->getPointeeType();
      else
        T = getPointerType(RT->getPointeeType());
    }
    QualType BaseT = getBaseElementType(T);
    if (T->isFunctionType())
      Align = getTypeInfoImpl(T.getTypePtr()).Align;
    else if (!BaseT->isIncompleteType()) {
      // Adjust alignments of declarations with array type by the
      // large-array alignment on the target.
      if (const ArrayType *arrayType = getAsArrayType(T)) {
        unsigned MinWidth = Target->getLargeArrayMinWidth();
        if (!ForAlignof && MinWidth) {
          if (isa<VariableArrayType>(arrayType))
            Align = std::max(Align, Target->getLargeArrayAlign());
          else if (isa<ConstantArrayType>(arrayType) &&
                   MinWidth <= getTypeSize(cast<ConstantArrayType>(arrayType)))
            Align = std::max(Align, Target->getLargeArrayAlign());
        }
      }
      Align = std::max(Align, getPreferredTypeAlign(T.getTypePtr()));
      if (BaseT.getQualifiers().hasUnaligned())
        Align = Target->getCharWidth();
      if (const auto *VD = dyn_cast<VarDecl>(D)) {
        if (VD->hasGlobalStorage() && !ForAlignof) {
          uint64_t TypeSize = getTypeSize(T.getTypePtr());
          Align = std::max(Align, getTargetInfo().getMinGlobalAlign(TypeSize));
        }
      }
    }
 
    // Fields can be subject to extra alignment constraints, like if
    // the field is packed, the struct is packed, or the struct has a
    // a max-field-alignment constraint (#pragma pack).  So calculate
    // the actual alignment of the field within the struct, and then
    // (as we're expected to) constrain that by the alignment of the type.
    if (const auto *Field = dyn_cast<FieldDecl>(VD)) {
      const RecordDecl *Parent = Field->getParent();
      // We can only produce a sensible answer if the record is valid.
      if (!Parent->isInvalidDecl()) {
        const ASTRecordLayout &Layout = getASTRecordLayout(Parent);
 
        // Start with the record's overall alignment.
        unsigned FieldAlign = toBits(Layout.getAlignment());
 
        // Use the GCD of that and the offset within the record.
        uint64_t Offset = Layout.getFieldOffset(Field->getFieldIndex());
        if (Offset > 0) {
          // Alignment is always a power of 2, so the GCD will be a power of 2,
          // which means we get to do this crazy thing instead of Euclid's.
          uint64_t LowBitOfOffset = Offset & (~Offset + 1);
          if (LowBitOfOffset < FieldAlign)
            FieldAlign = static_cast<unsigned>(LowBitOfOffset);
        }
 
        Align = std::min(Align, FieldAlign);
      }
    }
  }
 
  // Some targets have hard limitation on the maximum requestable alignment in
  // aligned attribute for static variables.
  const unsigned MaxAlignedAttr = getTargetInfo().getMaxAlignedAttribute();
  const auto *VD = dyn_cast<VarDecl>(D);
  if (MaxAlignedAttr && VD && VD->getStorageClass() == SC_Static)
    Align = std::min(Align, MaxAlignedAttr);
 
  return toCharUnitsFromBits(Align);
}
 
CharUnits ASTContext::getExnObjectAlignment() const {
  return toCharUnitsFromBits(Target->getExnObjectAlignment());
}
 
// getTypeInfoDataSizeInChars - Return the size of a type, in
// chars. If the type is a record, its data size is returned.  This is
// the size of the memcpy that's performed when assigning this type
// using a trivial copy/move assignment operator.
TypeInfoChars ASTContext::getTypeInfoDataSizeInChars(QualType T) const {
  TypeInfoChars Info = getTypeInfoInChars(T);
 
  // In C++, objects can sometimes be allocated into the tail padding
  // of a base-class subobject.  We decide whether that's possible
  // during class layout, so here we can just trust the layout results.
  if (getLangOpts().CPlusPlus) {
    if (const auto *RT = T->getAs<RecordType>()) {
      const ASTRecordLayout &layout = getASTRecordLayout(RT->getDecl());
      Info.Width = layout.getDataSize();
    }
  }
 
  return Info;
}
 
/// getConstantArrayInfoInChars - Performing the computation in CharUnits
/// instead of in bits prevents overflowing the uint64_t for some large arrays.
TypeInfoChars
static getConstantArrayInfoInChars(const ASTContext &Context,
                                   const ConstantArrayType *CAT) {
  TypeInfoChars EltInfo = Context.getTypeInfoInChars(CAT->getElementType());
  uint64_t Size = CAT->getSize().getZExtValue();
  assert((Size == 0 || static_cast<uint64_t>(EltInfo.Width.getQuantity()) <=
              (uint64_t)(-1)/Size) &&
         "Overflow in array type char size evaluation");
  uint64_t Width = EltInfo.Width.getQuantity() * Size;
  unsigned Align = EltInfo.Align.getQuantity();
  if (!Context.getTargetInfo().getCXXABI().isMicrosoft() ||
      Context.getTargetInfo().getPointerWidth(LangAS::Default) == 64)
    Width = llvm::alignTo(Width, Align);
  return TypeInfoChars(CharUnits::fromQuantity(Width),
                       CharUnits::fromQuantity(Align),
                       EltInfo.AlignRequirement);
}
 
TypeInfoChars ASTContext::getTypeInfoInChars(const Type *T) const {
  if (const auto *CAT = dyn_cast<ConstantArrayType>(T))
    return getConstantArrayInfoInChars(*this, CAT);
  TypeInfo Info = getTypeInfo(T);
  return TypeInfoChars(toCharUnitsFromBits(Info.Width),
                       toCharUnitsFromBits(Info.Align), Info.AlignRequirement);
}
 
TypeInfoChars ASTContext::getTypeInfoInChars(QualType T) const {
  return getTypeInfoInChars(T.getTypePtr());
}
 
bool ASTContext::isPromotableIntegerType(QualType T) const {
  // HLSL doesn't promote all small integer types to int, it
  // just uses the rank-based promotion rules for all types.
  if (getLangOpts().HLSL)
    return false;
 
  if (const auto *BT = T->getAs<BuiltinType>())
    switch (BT->getKind()) {
    case BuiltinType::Bool:
    case BuiltinType::Char_S:
    case BuiltinType::Char_U:
    case BuiltinType::SChar:
    case BuiltinType::UChar:
    case BuiltinType::Short:
    case BuiltinType::UShort:
    case BuiltinType::WChar_S:
    case BuiltinType::WChar_U:
    case BuiltinType::Char8:
    case BuiltinType::Char16:
    case BuiltinType::Char32:
      return true;
    default:
      return false;
    }
 
  // Enumerated types are promotable to their compatible integer types
  // (C99 6.3.1.1) a.k.a. its underlying type (C++ [conv.prom]p2).
  if (const auto *ET = T->getAs<EnumType>()) {
    if (T->isDependentType() || ET->getDecl()->getPromotionType().isNull() ||
        ET->getDecl()->isScoped())
      return false;
 
    return true;
  }
 
  return false;
}
 
bool ASTContext::isAlignmentRequired(const Type *T) const {
  return getTypeInfo(T).AlignRequirement != AlignRequirementKind::None;
}
 
bool ASTContext::isAlignmentRequired(QualType T) const {
  return isAlignmentRequired(T.getTypePtr());
}
 
unsigned ASTContext::getTypeAlignIfKnown(QualType T,
                                         bool NeedsPreferredAlignment) const {
  // An alignment on a typedef overrides anything else.
  if (const auto *TT = T->getAs<TypedefType>())
    if (unsigned Align = TT->getDecl()->getMaxAlignment())
      return Align;
 
  // If we have an (array of) complete type, we're done.
  T = getBaseElementType(T);
  if (!T->isIncompleteType())
    return NeedsPreferredAlignment ? getPreferredTypeAlign(T) : getTypeAlign(T);
 
  // If we had an array type, its element type might be a typedef
  // type with an alignment attribute.
  if (const auto *TT = T->getAs<TypedefType>())
    if (unsigned Align = TT->getDecl()->getMaxAlignment())
      return Align;
 
  // Otherwise, see if the declaration of the type had an attribute.
  if (const auto *TT = T->getAs<TagType>())
    return TT->getDecl()->getMaxAlignment();
 
  return 0;
}
 
TypeInfo ASTContext::getTypeInfo(const Type *T) const {
  TypeInfoMap::iterator I = MemoizedTypeInfo.find(T);
  if (I != MemoizedTypeInfo.end())
    return I->second;
 
  // This call can invalidate MemoizedTypeInfo[T], so we need a second lookup.
  TypeInfo TI = getTypeInfoImpl(T);
  MemoizedTypeInfo[T] = TI;
  return TI;
}
 
/// getTypeInfoImpl - Return the size of the specified type, in bits.  This
/// method does not work on incomplete types.
///
/// FIXME: Pointers into different addr spaces could have different sizes and
/// alignment requirements: getPointerInfo should take an AddrSpace, this
/// should take a QualType, &c.
TypeInfo ASTContext::getTypeInfoImpl(const Type *T) const {
  uint64_t Width = 0;
  unsigned Align = 8;
  AlignRequirementKind AlignRequirement = AlignRequirementKind::None;
  LangAS AS = LangAS::Default;
  switch (T->getTypeClass()) {
#define TYPE(Class, Base)
#define ABSTRACT_TYPE(Class, Base)
#define NON_CANONICAL_TYPE(Class, Base)
#define DEPENDENT_TYPE(Class, Base) case Type::Class:
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base)                       \
  case Type::Class:                                                            \
  assert(!T->isDependentType() && "should not see dependent types here");      \
  return getTypeInfo(cast<Class##Type>(T)->desugar().getTypePtr());
#include "clang/AST/TypeNodes.inc"
    llvm_unreachable("Should not see dependent types");
 
  case Type::FunctionNoProto:
  case Type::FunctionProto:
    // GCC extension: alignof(function) = 32 bits
    Width = 0;
    Align = 32;
    break;
 
  case Type::IncompleteArray:
  case Type::VariableArray:
  case Type::ConstantArray: {
    // Model non-constant sized arrays as size zero, but track the alignment.
    uint64_t Size = 0;
    if (const auto *CAT = dyn_cast<ConstantArrayType>(T))
      Size = CAT->getSize().getZExtValue();
 
    TypeInfo EltInfo = getTypeInfo(cast<ArrayType>(T)->getElementType());
    assert((Size == 0 || EltInfo.Width <= (uint64_t)(-1) / Size) &&
           "Overflow in array type bit size evaluation");
    Width = EltInfo.Width * Size;
    Align = EltInfo.Align;
    AlignRequirement = EltInfo.AlignRequirement;
    if (!getTargetInfo().getCXXABI().isMicrosoft() ||
        getTargetInfo().getPointerWidth(LangAS::Default) == 64)
      Width = llvm::alignTo(Width, Align);
    break;
  }
 
  case Type::ExtVector:
  case Type::Vector: {
    const auto *VT = cast<VectorType>(T);
    TypeInfo EltInfo = getTypeInfo(VT->getElementType());
    Width = VT->isExtVectorBoolType() ? VT->getNumElements()
                                      : EltInfo.Width * VT->getNumElements();
    // Enforce at least byte size and alignment.
    Width = std::max<unsigned>(8, Width);
    Align = std::max<unsigned>(8, Width);
 
    // If the alignment is not a power of 2, round up to the next power of 2.
    // This happens for non-power-of-2 length vectors.
    if (Align & (Align-1)) {
      Align = llvm::bit_ceil(Align);
      Width = llvm::alignTo(Width, Align);
    }
    // Adjust the alignment based on the target max.
    uint64_t TargetVectorAlign = Target->getMaxVectorAlign();
    if (TargetVectorAlign && TargetVectorAlign < Align)
      Align = TargetVectorAlign;
    if (VT->getVectorKind() == VectorType::SveFixedLengthDataVector)
      // Adjust the alignment for fixed-length SVE vectors. This is important
      // for non-power-of-2 vector lengths.
      Align = 128;
    else if (VT->getVectorKind() == VectorType::SveFixedLengthPredicateVector)
      // Adjust the alignment for fixed-length SVE predicates.
      Align = 16;
    else if (VT->getVectorKind() == VectorType::RVVFixedLengthDataVector)
      // Adjust the alignment for fixed-length RVV vectors.
      Align = 64;
    break;
  }
 
  case Type::ConstantMatrix: {
    const auto *MT = cast<ConstantMatrixType>(T);
    TypeInfo ElementInfo = getTypeInfo(MT->getElementType());
    // The internal layout of a matrix value is implementation defined.
    // Initially be ABI compatible with arrays with respect to alignment and
    // size.
    Width = ElementInfo.Width * MT->getNumRows() * MT->getNumColumns();
    Align = ElementInfo.Align;
    break;
  }
 
  case Type::Builtin:
    switch (cast<BuiltinType>(T)->getKind()) {
    default: llvm_unreachable("Unknown builtin type!");
    case BuiltinType::Void:
      // GCC extension: alignof(void) = 8 bits.
      Width = 0;
      Align = 8;
      break;
    case BuiltinType::Bool:
      Width = Target->getBoolWidth();
      Align = Target->getBoolAlign();
      break;
    case BuiltinType::Char_S:
    case BuiltinType::Char_U:
    case BuiltinType::UChar:
    case BuiltinType::SChar:
    case BuiltinType::Char8:
      Width = Target->getCharWidth();
      Align = Target->getCharAlign();
      break;
    case BuiltinType::WChar_S:
    case BuiltinType::WChar_U:
      Width = Target->getWCharWidth();
      Align = Target->getWCharAlign();
      break;
    case BuiltinType::Char16:
      Width = Target->getChar16Width();
      Align = Target->getChar16Align();
      break;
    case BuiltinType::Char32:
      Width = Target->getChar32Width();
      Align = Target->getChar32Align();
      break;
    case BuiltinType::UShort:
    case BuiltinType::Short:
      Width = Target->getShortWidth();
      Align = Target->getShortAlign();
      break;
    case BuiltinType::UInt:
    case BuiltinType::Int:
      Width = Target->getIntWidth();
      Align = Target->getIntAlign();
      break;
    case BuiltinType::ULong:
    case BuiltinType::Long:
      Width = Target->getLongWidth();
      Align = Target->getLongAlign();
      break;
    case BuiltinType::ULongLong:
    case BuiltinType::LongLong:
      Width = Target->getLongLongWidth();
      Align = Target->getLongLongAlign();
      break;
    case BuiltinType::Int128:
    case BuiltinType::UInt128:
      Width = 128;
      Align = Target->getInt128Align();
      break;
    case BuiltinType::ShortAccum:
    case BuiltinType::UShortAccum:
    case BuiltinType::SatShortAccum:
    case BuiltinType::SatUShortAccum:
      Width = Target->getShortAccumWidth();
      Align = Target->getShortAccumAlign();
      break;
    case BuiltinType::Accum:
    case BuiltinType::UAccum:
    case BuiltinType::SatAccum:
    case BuiltinType::SatUAccum:
      Width = Target->getAccumWidth();
      Align = Target->getAccumAlign();
      break;
    case BuiltinType::LongAccum:
    case BuiltinType::ULongAccum:
    case BuiltinType::SatLongAccum:
    case BuiltinType::SatULongAccum:
      Width = Target->getLongAccumWidth();
      Align = Target->getLongAccumAlign();
      break;
    case BuiltinType::ShortFract:
    case BuiltinType::UShortFract:
    case BuiltinType::SatShortFract:
    case BuiltinType::SatUShortFract:
      Width = Target->getShortFractWidth();
      Align = Target->getShortFractAlign();
      break;
    case BuiltinType::Fract:
    case BuiltinType::UFract:
    case BuiltinType::SatFract:
    case BuiltinType::SatUFract:
      Width = Target->getFractWidth();
      Align = Target->getFractAlign();
      break;
    case BuiltinType::LongFract:
    case BuiltinType::ULongFract:
    case BuiltinType::SatLongFract:
    case BuiltinType::SatULongFract:
      Width = Target->getLongFractWidth();
      Align = Target->getLongFractAlign();
      break;
    case BuiltinType::BFloat16:
      if (Target->hasBFloat16Type()) {
        Width = Target->getBFloat16Width();
        Align = Target->getBFloat16Align();
      } else if ((getLangOpts().SYCLIsDevice ||
                  (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice)) &&
                 AuxTarget->hasBFloat16Type()) {
        Width = AuxTarget->getBFloat16Width();
        Align = AuxTarget->getBFloat16Align();
      }
      break;
    case BuiltinType::Float16:
    case BuiltinType::Half:
      if (Target->hasFloat16Type() || !getLangOpts().OpenMP ||
          !getLangOpts().OpenMPIsDevice) {
        Width = Target->getHalfWidth();
        Align = Target->getHalfAlign();
      } else {
        assert(getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice &&
               "Expected OpenMP device compilation.");
        Width = AuxTarget->getHalfWidth();
        Align = AuxTarget->getHalfAlign();
      }
      break;
    case BuiltinType::Float:
      Width = Target->getFloatWidth();
      Align = Target->getFloatAlign();
      break;
    case BuiltinType::Double:
      Width = Target->getDoubleWidth();
      Align = Target->getDoubleAlign();
      break;
    case BuiltinType::Ibm128:
      Width = Target->getIbm128Width();
      Align = Target->getIbm128Align();
      break;
    case BuiltinType::LongDouble:
      if (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice &&
          (Target->getLongDoubleWidth() != AuxTarget->getLongDoubleWidth() ||
           Target->getLongDoubleAlign() != AuxTarget->getLongDoubleAlign())) {
        Width = AuxTarget->getLongDoubleWidth();
        Align = AuxTarget->getLongDoubleAlign();
      } else {
        Width = Target->getLongDoubleWidth();
        Align = Target->getLongDoubleAlign();
      }
      break;
    case BuiltinType::Float128:
      if (Target->hasFloat128Type() || !getLangOpts().OpenMP ||
          !getLangOpts().OpenMPIsDevice) {
        Width = Target->getFloat128Width();
        Align = Target->getFloat128Align();
      } else {
        assert(getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice &&
               "Expected OpenMP device compilation.");
        Width = AuxTarget->getFloat128Width();
        Align = AuxTarget->getFloat128Align();
      }
      break;
    case BuiltinType::NullPtr:
      // C++ 3.9.1p11: sizeof(nullptr_t) == sizeof(void*)
      Width = Target->getPointerWidth(LangAS::Default);
      Align = Target->getPointerAlign(LangAS::Default);
      break;
    case BuiltinType::ObjCId:
    case BuiltinType::ObjCClass:
    case BuiltinType::ObjCSel:
      Width = Target->getPointerWidth(LangAS::Default);
      Align = Target->getPointerAlign(LangAS::Default);
      break;
    case BuiltinType::OCLSampler:
    case BuiltinType::OCLEvent:
    case BuiltinType::OCLClkEvent:
    case BuiltinType::OCLQueue:
    case BuiltinType::OCLReserveID:
#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
    case BuiltinType::Id:
#include "clang/Basic/OpenCLImageTypes.def"
#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
  case BuiltinType::Id:
#include "clang/Basic/OpenCLExtensionTypes.def"
      AS = Target->getOpenCLTypeAddrSpace(getOpenCLTypeKind(T));
      Width = Target->getPointerWidth(AS);
      Align = Target->getPointerAlign(AS);
      break;
    // The SVE types are effectively target-specific.  The length of an
    // SVE_VECTOR_TYPE is only known at runtime, but it is always a multiple
    // of 128 bits.  There is one predicate bit for each vector byte, so the
    // length of an SVE_PREDICATE_TYPE is always a multiple of 16 bits.
    //
    // Because the length is only known at runtime, we use a dummy value
    // of 0 for the static length.  The alignment values are those defined
    // by the Procedure Call Standard for the Arm Architecture.
#define SVE_VECTOR_TYPE(Name, MangledName, Id, SingletonId, NumEls, ElBits,    \
                        IsSigned, IsFP, IsBF)                                  \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 128;                                                               \
    break;
#define SVE_PREDICATE_TYPE(Name, MangledName, Id, SingletonId, NumEls)         \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 16;                                                                \
    break;
#define SVE_OPAQUE_TYPE(Name, MangledName, Id, SingletonId)                    \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 16;                                                                \
    break;
#include "clang/Basic/AArch64SVEACLETypes.def"
#define PPC_VECTOR_TYPE(Name, Id, Size)                                        \
  case BuiltinType::Id:                                                        \
    Width = Size;                                                              \
    Align = Size;                                                              \
    break;
#include "clang/Basic/PPCTypes.def"
#define RVV_VECTOR_TYPE(Name, Id, SingletonId, ElKind, ElBits, NF, IsSigned,   \
                        IsFP)                                                  \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = ElBits;                                                            \
    break;
#define RVV_PREDICATE_TYPE(Name, Id, SingletonId, ElKind)                      \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 8;                                                                 \
    break;
#include "clang/Basic/RISCVVTypes.def"
#define WASM_TYPE(Name, Id, SingletonId)                                       \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 8;                                                                 \
    break;
#include "clang/Basic/WebAssemblyReferenceTypes.def"
    }
    break;
  case Type::ObjCObjectPointer:
    Width = Target->getPointerWidth(LangAS::Default);
    Align = Target->getPointerAlign(LangAS::Default);
    break;
  case Type::BlockPointer:
    AS = cast<BlockPointerType>(T)->getPointeeType().getAddressSpace();
    Width = Target->getPointerWidth(AS);
    Align = Target->getPointerAlign(AS);
    break;
  case Type::LValueReference:
  case Type::RValueReference:
    // alignof and sizeof should never enter this code path here, so we go
    // the pointer route.
    AS = cast<ReferenceType>(T)->getPointeeType().getAddressSpace();
    Width = Target->getPointerWidth(AS);
    Align = Target->getPointerAlign(AS);
    break;
  case Type::Pointer:
    AS = cast<PointerType>(T)->getPointeeType().getAddressSpace();
    Width = Target->getPointerWidth(AS);
    Align = Target->getPointerAlign(AS);
    break;
  case Type::MemberPointer: {
    const auto *MPT = cast<MemberPointerType>(T);
    CXXABI::MemberPointerInfo MPI = ABI->getMemberPointerInfo(MPT);
    Width = MPI.Width;
    Align = MPI.Align;
    break;
  }
  case Type::Complex: {
    // Complex types have the same alignment as their elements, but twice the
    // size.
    TypeInfo EltInfo = getTypeInfo(cast<ComplexType>(T)->getElementType());
    Width = EltInfo.Width * 2;
    Align = EltInfo.Align;
    break;
  }
  case Type::ObjCObject:
    return getTypeInfo(cast<ObjCObjectType>(T)->getBaseType().getTypePtr());
  case Type::Adjusted:
  case Type::Decayed:
    return getTypeInfo(cast<AdjustedType>(T)->getAdjustedType().getTypePtr());
  case Type::ObjCInterface: {
    const auto *ObjCI = cast<ObjCInterfaceType>(T);
    if (ObjCI->getDecl()->isInvalidDecl()) {
      Width = 8;
      Align = 8;
      break;
    }
    const ASTRecordLayout &Layout = getASTObjCInterfaceLayout(ObjCI->getDecl());
    Width = toBits(Layout.getSize());
    Align = toBits(Layout.getAlignment());
    break;
  }
  case Type::BitInt: {
    const auto *EIT = cast<BitIntType>(T);
    Align = std::clamp<unsigned>(llvm::PowerOf2Ceil(EIT->getNumBits()),
                                 getCharWidth(), Target->getLongLongAlign());
    Width = llvm::alignTo(EIT->getNumBits(), Align);
    break;
  }
  case Type::Record:
  case Type::Enum: {
    const auto *TT = cast<TagType>(T);
 
    if (TT->getDecl()->isInvalidDecl()) {
      Width = 8;
      Align = 8;
      break;
    }
 
    if (const auto *ET = dyn_cast<EnumType>(TT)) {
      const EnumDecl *ED = ET->getDecl();
      TypeInfo Info =
          getTypeInfo(ED->getIntegerType()->getUnqualifiedDesugaredType());
      if (unsigned AttrAlign = ED->getMaxAlignment()) {
        Info.Align = AttrAlign;
        Info.AlignRequirement = AlignRequirementKind::RequiredByEnum;
      }
      return Info;
    }
 
    const auto *RT = cast<RecordType>(TT);
    const RecordDecl *RD = RT->getDecl();
    const ASTRecordLayout &Layout = getASTRecordLayout(RD);
    Width = toBits(Layout.getSize());
    Align = toBits(Layout.getAlignment());
    AlignRequirement = RD->hasAttr<AlignedAttr>()
                           ? AlignRequirementKind::RequiredByRecord
                           : AlignRequirementKind::None;
    break;
  }
 
  case Type::SubstTemplateTypeParm:
    return getTypeInfo(cast<SubstTemplateTypeParmType>(T)->
                       getReplacementType().getTypePtr());
 
  case Type::Auto:
  case Type::DeducedTemplateSpecialization: {
    const auto *A = cast<DeducedType>(T);
    assert(!A->getDeducedType().isNull() &&
           "cannot request the size of an undeduced or dependent auto type");
    return getTypeInfo(A->getDeducedType().getTypePtr());
  }
 
  case Type::Paren:
    return getTypeInfo(cast<ParenType>(T)->getInnerType().getTypePtr());
 
  case Type::MacroQualified:
    return getTypeInfo(
        cast<MacroQualifiedType>(T)->getUnderlyingType().getTypePtr());
 
  case Type::ObjCTypeParam:
    return getTypeInfo(cast<ObjCTypeParamType>(T)->desugar().getTypePtr());
 
  case Type::Using:
    return getTypeInfo(cast<UsingType>(T)->desugar().getTypePtr());
 
  case Type::Typedef: {
    const auto *TT = cast<TypedefType>(T);
    TypeInfo Info = getTypeInfo(TT->desugar().getTypePtr());
    // If the typedef has an aligned attribute on it, it overrides any computed
    // alignment we have.  This violates the GCC documentation (which says that
    // attribute(aligned) can only round up) but matches its implementation.
    if (unsigned AttrAlign = TT->getDecl()->getMaxAlignment()) {
      Align = AttrAlign;
      AlignRequirement = AlignRequirementKind::RequiredByTypedef;
    } else {
      Align = Info.Align;
      AlignRequirement = Info.AlignRequirement;
    }
    Width = Info.Width;
    break;
  }
 
  case Type::Elaborated:
    return getTypeInfo(cast<ElaboratedType>(T)->getNamedType().getTypePtr());
 
  case Type::Attributed:
    return getTypeInfo(
                  cast<AttributedType>(T)->getEquivalentType().getTypePtr());
 
  case Type::BTFTagAttributed:
    return getTypeInfo(
        cast<BTFTagAttributedType>(T)->getWrappedType().getTypePtr());
 
  case Type::Atomic: {
    // Start with the base type information.
    TypeInfo Info = getTypeInfo(cast<AtomicType>(T)->getValueType());
    Width = Info.Width;
    Align = Info.Align;
 
    if (!Width) {
      // An otherwise zero-sized type should still generate an
      // atomic operation.
      Width = Target->getCharWidth();
      assert(Align);
    } else if (Width <= Target->getMaxAtomicPromoteWidth()) {
      // If the size of the type doesn't exceed the platform's max
      // atomic promotion width, make the size and alignment more
      // favorable to atomic operations:
 
      // Round the size up to a power of 2.
      Width = llvm::bit_ceil(Width);
 
      // Set the alignment equal to the size.
      Align = static_cast<unsigned>(Width);
    }
  }
  break;
 
  case Type::Pipe:
    Width = Target->getPointerWidth(LangAS::opencl_global);
    Align = Target->getPointerAlign(LangAS::opencl_global);
    break;
  }
 
  assert(llvm::isPowerOf2_32(Align) && "Alignment must be power of 2");
  return TypeInfo(Width, Align, AlignRequirement);
}
 
unsigned ASTContext::getTypeUnadjustedAlign(const Type *T) const {
  UnadjustedAlignMap::iterator I = MemoizedUnadjustedAlign.find(T);
  if (I != MemoizedUnadjustedAlign.end())
    return I->second;
 
  unsigned UnadjustedAlign;
  if (const auto *RT = T->getAs<RecordType>()) {
    const RecordDecl *RD = RT->getDecl();
    const ASTRecordLayout &Layout = getASTRecordLayout(RD);
    UnadjustedAlign = toBits(Layout.getUnadjustedAlignment());
  } else if (const auto *ObjCI = T->getAs<ObjCInterfaceType>()) {
    const ASTRecordLayout &Layout = getASTObjCInterfaceLayout(ObjCI->getDecl());
    UnadjustedAlign = toBits(Layout.getUnadjustedAlignment());
  } else {
    UnadjustedAlign = getTypeAlign(T->getUnqualifiedDesugaredType());
  }
 
  MemoizedUnadjustedAlign[T] = UnadjustedAlign;
  return UnadjustedAlign;
}
 
unsigned ASTContext::getOpenMPDefaultSimdAlign(QualType T) const {
  unsigned SimdAlign = llvm::OpenMPIRBuilder::getOpenMPDefaultSimdAlign(
      getTargetInfo().getTriple(), Target->getTargetOpts().FeatureMap);
  return SimdAlign;
}
 
/// toCharUnitsFromBits - Convert a size in bits to a size in characters.
CharUnits ASTContext::toCharUnitsFromBits(int64_t BitSize) const {
  return CharUnits::fromQuantity(BitSize / getCharWidth());
}
 
/// toBits - Convert a size in characters to a size in characters.
int64_t ASTContext::toBits(CharUnits CharSize) const {
  return CharSize.getQuantity() * getCharWidth();
}
 
/// getTypeSizeInChars - Return the size of the specified type, in characters.
/// This method does not work on incomplete types.
CharUnits ASTContext::getTypeSizeInChars(QualType T) const {
  return getTypeInfoInChars(T).Width;
}
CharUnits ASTContext::getTypeSizeInChars(const Type *T) const {
  return getTypeInfoInChars(T).Width;
}
 
/// getTypeAlignInChars - Return the ABI-specified alignment of a type, in
/// characters. This method does not work on incomplete types.
CharUnits ASTContext::getTypeAlignInChars(QualType T) const {
  return toCharUnitsFromBits(getTypeAlign(T));
}
CharUnits ASTContext::getTypeAlignInChars(const Type *T) const {
  return toCharUnitsFromBits(getTypeAlign(T));
}
 
/// getTypeUnadjustedAlignInChars - Return the ABI-specified alignment of a
/// type, in characters, before alignment adjustments. This method does
/// not work on incomplete types.
CharUnits ASTContext::getTypeUnadjustedAlignInChars(QualType T) const {
  return toCharUnitsFromBits(getTypeUnadjustedAlign(T));
}
CharUnits ASTContext::getTypeUnadjustedAlignInChars(const Type *T) const {
  return toCharUnitsFromBits(getTypeUnadjustedAlign(T));
}
 
/// getPreferredTypeAlign - Return the "preferred" alignment of the specified
/// type for the current target in bits.  This can be different than the ABI
/// alignment in cases where it is beneficial for performance or backwards
/// compatibility preserving to overalign a data type. (Note: despite the name,
/// the preferred alignment is ABI-impacting, and not an optimization.)
unsigned ASTContext::getPreferredTypeAlign(const Type *T) const {
  TypeInfo TI = getTypeInfo(T);
  unsigned ABIAlign = TI.Align;
 
  T = T->getBaseElementTypeUnsafe();
 
  // The preferred alignment of member pointers is that of a pointer.
  if (T->isMemberPointerType())
    return getPreferredTypeAlign(getPointerDiffType().getTypePtr());
 
  if (!Target->allowsLargerPreferedTypeAlignment())
    return ABIAlign;
 
  if (const auto *RT = T->getAs<RecordType>()) {
    const RecordDecl *RD = RT->getDecl();
 
    // When used as part of a typedef, or together with a 'packed' attribute,
    // the 'aligned' attribute can be used to decrease alignment. Note that the
    // 'packed' case is already taken into consideration when computing the
    // alignment, we only need to handle the typedef case here.
    if (TI.AlignRequirement == AlignRequirementKind::RequiredByTypedef ||
        RD->isInvalidDecl())
      return ABIAlign;
 
    unsigned PreferredAlign = static_cast<unsigned>(
        toBits(getASTRecordLayout(RD).PreferredAlignment));
    assert(PreferredAlign >= ABIAlign &&
           "PreferredAlign should be at least as large as ABIAlign.");
    return PreferredAlign;
  }
 
  // Double (and, for targets supporting AIX `power` alignment, long double) and
  // long long should be naturally aligned (despite requiring less alignment) if
  // possible.
  if (const auto *CT = T->getAs<ComplexType>())
    T = CT->getElementType().getTypePtr();
  if (const auto *ET = T->getAs<EnumType>())
    T = ET->getDecl()->getIntegerType().getTypePtr();
  if (T->isSpecificBuiltinType(BuiltinType::Double) ||
      T->isSpecificBuiltinType(BuiltinType::LongLong) ||
      T->isSpecificBuiltinType(BuiltinType::ULongLong) ||
      (T->isSpecificBuiltinType(BuiltinType::LongDouble) &&
       Target->defaultsToAIXPowerAlignment()))
    // Don't increase the alignment if an alignment attribute was specified on a
    // typedef declaration.
    if (!TI.isAlignRequired())
      return std::max(ABIAlign, (unsigned)getTypeSize(T));
 
  return ABIAlign;
}
 
/// getTargetDefaultAlignForAttributeAligned - Return the default alignment
/// for __attribute__((aligned)) on this target, to be used if no alignment
/// value is specified.
unsigned ASTContext::getTargetDefaultAlignForAttributeAligned() const {
  return getTargetInfo().getDefaultAlignForAttributeAligned();
}
 
/// getAlignOfGlobalVar - Return the alignment in bits that should be given
/// to a global variable of the specified type.
unsigned ASTContext::getAlignOfGlobalVar(QualType T) const {
  uint64_t TypeSize = getTypeSize(T.getTypePtr());
  return std::max(getPreferredTypeAlign(T),
                  getTargetInfo().getMinGlobalAlign(TypeSize));
}
 
/// getAlignOfGlobalVarInChars - Return the alignment in characters that
/// should be given to a global variable of the specified type.
CharUnits ASTContext::getAlignOfGlobalVarInChars(QualType T) const {
  return toCharUnitsFromBits(getAlignOfGlobalVar(T));
}
 
CharUnits ASTContext::getOffsetOfBaseWithVBPtr(const CXXRecordDecl *RD) const {
  CharUnits Offset = CharUnits::Zero();
  const ASTRecordLayout *Layout = &getASTRecordLayout(RD);
  while (const CXXRecordDecl *Base = Layout->getBaseSharingVBPtr()) {
    Offset += Layout->getBaseClassOffset(Base);
    Layout = &getASTRecordLayout(Base);
  }
  return Offset;
}
 
CharUnits ASTContext::getMemberPointerPathAdjustment(const APValue &MP) const {
  const ValueDecl *MPD = MP.getMemberPointerDecl();
  CharUnits ThisAdjustment = CharUnits::Zero();
  ArrayRef<const CXXRecordDecl*> Path = MP.getMemberPointerPath();
  bool DerivedMember = MP.isMemberPointerToDerivedMember();
  const CXXRecordDecl *RD = cast<CXXRecordDecl>(MPD->getDeclContext());
  for (unsigned I = 0, N = Path.size(); I != N; ++I) {
    const CXXRecordDecl *Base = RD;
    const CXXRecordDecl *Derived = Path[I];
    if (DerivedMember)
      std::swap(Base, Derived);
    ThisAdjustment += getASTRecordLayout(Derived).getBaseClassOffset(Base);
    RD = Path[I];
  }
  if (DerivedMember)
    ThisAdjustment = -ThisAdjustment;
  return ThisAdjustment;
}
 
/// DeepCollectObjCIvars -
/// This routine first collects all declared, but not synthesized, ivars in
/// super class and then collects all ivars, including those synthesized for
/// current class. This routine is used for implementation of current class
/// when all ivars, declared and synthesized are known.
void ASTContext::DeepCollectObjCIvars(const ObjCInterfaceDecl *OI,
                                      bool leafClass,
                            SmallVectorImpl<const ObjCIvarDecl*> &Ivars) const {
  if (const ObjCInterfaceDecl *SuperClass = OI->getSuperClass())
    DeepCollectObjCIvars(SuperClass, false, Ivars);
  if (!leafClass) {
    llvm::append_range(Ivars, OI->ivars());
  } else {
    auto *IDecl = const_cast<ObjCInterfaceDecl *>(OI);
    for (const ObjCIvarDecl *Iv = IDecl->all_declared_ivar_begin(); Iv;
         Iv= Iv->getNextIvar())
      Ivars.push_back(Iv);
  }
}
 
/// CollectInheritedProtocols - Collect all protocols in current class and
/// those inherited by it.
void ASTContext::CollectInheritedProtocols(const Decl *CDecl,
                          llvm::SmallPtrSet<ObjCProtocolDecl*, 8> &Protocols) {
  if (const auto *OI = dyn_cast<ObjCInterfaceDecl>(CDecl)) {
    // We can use protocol_iterator here instead of
    // all_referenced_protocol_iterator since we are walking all categories.
    for (auto *Proto : OI->all_referenced_protocols()) {
      CollectInheritedProtocols(Proto, Protocols);
    }
 
    // Categories of this Interface.
    for (const auto *Cat : OI->visible_categories())
      CollectInheritedProtocols(Cat, Protocols);
 
    if (ObjCInterfaceDecl *SD = OI->getSuperClass())
      while (SD) {
        CollectInheritedProtocols(SD, Protocols);
        SD = SD->getSuperClass();
      }
  } else if (const auto *OC = dyn_cast<ObjCCategoryDecl>(CDecl)) {
    for (auto *Proto : OC->protocols()) {
      CollectInheritedProtocols(Proto, Protocols);
    }
  } else if (const auto *OP = dyn_cast<ObjCProtocolDecl>(CDecl)) {
    // Insert the protocol.
    if (!Protocols.insert(
          const_cast<ObjCProtocolDecl *>(OP->getCanonicalDecl())).second)
      return;
 
    for (auto *Proto : OP->protocols())
      CollectInheritedProtocols(Proto, Protocols);
  }
}
 
static bool unionHasUniqueObjectRepresentations(const ASTContext &Context,
                                                const RecordDecl *RD,
                                                bool CheckIfTriviallyCopyable) {
  assert(RD->isUnion() && "Must be union type");
  CharUnits UnionSize = Context.getTypeSizeInChars(RD->getTypeForDecl());
 
  for (const auto *Field : RD->fields()) {
    if (!Context.hasUniqueObjectRepresentations(Field->getType(),
                                                CheckIfTriviallyCopyable))
      return false;
    CharUnits FieldSize = Context.getTypeSizeInChars(Field->getType());
    if (FieldSize != UnionSize)
      return false;
  }
  return !RD->field_empty();
}
 
static int64_t getSubobjectOffset(const FieldDecl *Field,
                                  const ASTContext &Context,
                                  const clang::ASTRecordLayout & /*Layout*/) {
  return Context.getFieldOffset(Field);
}
 
static int64_t getSubobjectOffset(const CXXRecordDecl *RD,
                                  const ASTContext &Context,
                                  const clang::ASTRecordLayout &Layout) {
  return Context.toBits(Layout.getBaseClassOffset(RD));
}
 
static std::optional<int64_t>
structHasUniqueObjectRepresentations(const ASTContext &Context,
                                     const RecordDecl *RD,
                                     bool CheckIfTriviallyCopyable);
 
static std::optional<int64_t>
getSubobjectSizeInBits(const FieldDecl *Field, const ASTContext &Context,
                       bool CheckIfTriviallyCopyable) {
  if (Field->getType()->isRecordType()) {
    const RecordDecl *RD = Field->getType()->getAsRecordDecl();
    if (!RD->isUnion())
      return structHasUniqueObjectRepresentations(Context, RD,
                                                  CheckIfTriviallyCopyable);
  }
 
  // A _BitInt type may not be unique if it has padding bits
  // but if it is a bitfield the padding bits are not used.
  bool IsBitIntType = Field->getType()->isBitIntType();
  if (!Field->getType()->isReferenceType() && !IsBitIntType &&
      !Context.hasUniqueObjectRepresentations(Field->getType(),
                                              CheckIfTriviallyCopyable))
    return std::nullopt;
 
  int64_t FieldSizeInBits =
      Context.toBits(Context.getTypeSizeInChars(Field->getType()));
  if (Field->isBitField()) {
    // If we have explicit padding bits, they don't contribute bits
    // to the actual object representation, so return 0.
    if (Field->isUnnamedBitfield())
      return 0;
 
    int64_t BitfieldSize = Field->getBitWidthValue(Context);
    if (IsBitIntType) {
      if ((unsigned)BitfieldSize >
          cast<BitIntType>(Field->getType())->getNumBits())
        return std::nullopt;
    } else if (BitfieldSize > FieldSizeInBits) {
      return std::nullopt;
    }
    FieldSizeInBits = BitfieldSize;
  } else if (IsBitIntType && !Context.hasUniqueObjectRepresentations(
                                 Field->getType(), CheckIfTriviallyCopyable)) {
    return std::nullopt;
  }
  return FieldSizeInBits;
}
 
static std::optional<int64_t>
getSubobjectSizeInBits(const CXXRecordDecl *RD, const ASTContext &Context,
                       bool CheckIfTriviallyCopyable) {
  return structHasUniqueObjectRepresentations(Context, RD,
                                              CheckIfTriviallyCopyable);
}
 
template <typename RangeT>
static std::optional<int64_t> structSubobjectsHaveUniqueObjectRepresentations(
    const RangeT &Subobjects, int64_t CurOffsetInBits,
    const ASTContext &Context, const clang::ASTRecordLayout &Layout,
    bool CheckIfTriviallyCopyable) {
  for (const auto *Subobject : Subobjects) {
    std::optional<int64_t> SizeInBits =
        getSubobjectSizeInBits(Subobject, Context, CheckIfTriviallyCopyable);
    if (!SizeInBits)
      return std::nullopt;
    if (*SizeInBits != 0) {
      int64_t Offset = getSubobjectOffset(Subobject, Context, Layout);
      if (Offset != CurOffsetInBits)
        return std::nullopt;
      CurOffsetInBits += *SizeInBits;
    }
  }
  return CurOffsetInBits;
}
 
static std::optional<int64_t>
structHasUniqueObjectRepresentations(const ASTContext &Context,
                                     const RecordDecl *RD,
                                     bool CheckIfTriviallyCopyable) {
  assert(!RD->isUnion() && "Must be struct/class type");
  const auto &Layout = Context.getASTRecordLayout(RD);
 
  int64_t CurOffsetInBits = 0;
  if (const auto *ClassDecl = dyn_cast<CXXRecordDecl>(RD)) {
    if (ClassDecl->isDynamicClass())
      return std::nullopt;
 
    SmallVector<CXXRecordDecl *, 4> Bases;
    for (const auto &Base : ClassDecl->bases()) {
      // Empty types can be inherited from, and non-empty types can potentially
      // have tail padding, so just make sure there isn't an error.
      Bases.emplace_back(Base.getType()->getAsCXXRecordDecl());
    }
 
    llvm::sort(Bases, [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
      return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
    });
 
    std::optional<int64_t> OffsetAfterBases =
        structSubobjectsHaveUniqueObjectRepresentations(
            Bases, CurOffsetInBits, Context, Layout, CheckIfTriviallyCopyable);
    if (!OffsetAfterBases)
      return std::nullopt;
    CurOffsetInBits = *OffsetAfterBases;
  }
 
  std::optional<int64_t> OffsetAfterFields =
      structSubobjectsHaveUniqueObjectRepresentations(
          RD->fields(), CurOffsetInBits, Context, Layout,
          CheckIfTriviallyCopyable);
  if (!OffsetAfterFields)
    return std::nullopt;
  CurOffsetInBits = *OffsetAfterFields;
 
  return CurOffsetInBits;
}
 
bool ASTContext::hasUniqueObjectRepresentations(
    QualType Ty, bool CheckIfTriviallyCopyable) const {
  // C++17 [meta.unary.prop]:
  //   The predicate condition for a template specialization
  //   has_unique_object_representations<T> shall be
  //   satisfied if and only if:
  //     (9.1) - T is trivially copyable, and
  //     (9.2) - any two objects of type T with the same value have the same
  //     object representation, where two objects
  //   of array or non-union class type are considered to have the same value
  //   if their respective sequences of
  //   direct subobjects have the same values, and two objects of union type
  //   are considered to have the same
  //   value if they have the same active member and the corresponding members
  //   have the same value.
  //   The set of scalar types for which this condition holds is
  //   implementation-defined. [ Note: If a type has padding
  //   bits, the condition does not hold; otherwise, the condition holds true
  //   for unsigned integral types. -- end note ]
  assert(!Ty.isNull() && "Null QualType sent to unique object rep check");
 
  // Arrays are unique only if their element type is unique.
  if (Ty->isArrayType())
    return hasUniqueObjectRepresentations(getBaseElementType(Ty),
                                          CheckIfTriviallyCopyable);
 
  // (9.1) - T is trivially copyable...
  if (CheckIfTriviallyCopyable && !Ty.isTriviallyCopyableType(*this))
    return false;
 
  // All integrals and enums are unique.
  if (Ty->isIntegralOrEnumerationType()) {
    // Except _BitInt types that have padding bits.
    if (const auto *BIT = Ty->getAs<BitIntType>())
      return getTypeSize(BIT) == BIT->getNumBits();
 
    return true;
  }
 
  // All other pointers are unique.
  if (Ty->isPointerType())
    return true;
 
  if (const auto *MPT = Ty->getAs<MemberPointerType>())
    return !ABI->getMemberPointerInfo(MPT).HasPadding;
 
  if (Ty->isRecordType()) {
    const RecordDecl *Record = Ty->castAs<RecordType>()->getDecl();
 
    if (Record->isInvalidDecl())
      return false;
 
    if (Record->isUnion())
      return unionHasUniqueObjectRepresentations(*this, Record,
                                                 CheckIfTriviallyCopyable);
 
    std::optional<int64_t> StructSize = structHasUniqueObjectRepresentations(
        *this, Record, CheckIfTriviallyCopyable);
 
    return StructSize && *StructSize == static_cast<int64_t>(getTypeSize(Ty));
  }
 
  // FIXME: More cases to handle here (list by rsmith):
  // vectors (careful about, eg, vector of 3 foo)
  // _Complex int and friends
  // _Atomic T
  // Obj-C block pointers
  // Obj-C object pointers
  // and perhaps OpenCL's various builtin types (pipe, sampler_t, event_t,
  // clk_event_t, queue_t, reserve_id_t)
  // There're also Obj-C class types and the Obj-C selector type, but I think it
  // makes sense for those to return false here.
 
  return false;
}
 
unsigned ASTContext::CountNonClassIvars(const ObjCInterfaceDecl *OI) const {
  unsigned count = 0;
  // Count ivars declared in class extension.
  for (const auto *Ext : OI->known_extensions())
    count += Ext->ivar_size();
 
  // Count ivar defined in this class's implementation.  This
  // includes synthesized ivars.
  if (ObjCImplementationDecl *ImplDecl = OI->getImplementation())
    count += ImplDecl->ivar_size();
 
  return count;
}
 
bool ASTContext::isSentinelNullExpr(const Expr *E) {
  if (!E)
    return false;
 
  // nullptr_t is always treated as null.
  if (E->getType()->isNullPtrType()) return true;
 
  if (E->getType()->isAnyPointerType() &&
      E->IgnoreParenCasts()->isNullPointerConstant(*this,
                                                Expr::NPC_ValueDependentIsNull))
    return true;
 
  // Unfortunately, __null has type 'int'.
  if (isa<GNUNullExpr>(E)) return true;
 
  return false;
}
 
/// Get the implementation of ObjCInterfaceDecl, or nullptr if none
/// exists.
ObjCImplementationDecl *ASTContext::getObjCImplementation(ObjCInterfaceDecl *D) {
  llvm::DenseMap<ObjCContainerDecl*, ObjCImplDecl*>::iterator
    I = ObjCImpls.find(D);
  if (I != ObjCImpls.end())
    return cast<ObjCImplementationDecl>(I->second);
  return nullptr;
}
 
/// Get the implementation of ObjCCategoryDecl, or nullptr if none
/// exists.
ObjCCategoryImplDecl *ASTContext::getObjCImplementation(ObjCCategoryDecl *D) {
  llvm::DenseMap<ObjCContainerDecl*, ObjCImplDecl*>::iterator
    I = ObjCImpls.find(D);
  if (I != ObjCImpls.end())
    return cast<ObjCCategoryImplDecl>(I->second);
  return nullptr;
}
 
/// Set the implementation of ObjCInterfaceDecl.
void ASTContext::setObjCImplementation(ObjCInterfaceDecl *IFaceD,
                           ObjCImplementationDecl *ImplD) {
  assert(IFaceD && ImplD && "Passed null params");
  ObjCImpls[IFaceD] = ImplD;
}
 
/// Set the implementation of ObjCCategoryDecl.
void ASTContext::setObjCImplementation(ObjCCategoryDecl *CatD,
                           ObjCCategoryImplDecl *ImplD) {
  assert(CatD && ImplD && "Passed null params");
  ObjCImpls[CatD] = ImplD;
}
 
const ObjCMethodDecl *
ASTContext::getObjCMethodRedeclaration(const ObjCMethodDecl *MD) const {
  return ObjCMethodRedecls.lookup(MD);
}
 
void ASTContext::setObjCMethodRedeclaration(const ObjCMethodDecl *MD,
                                            const ObjCMethodDecl *Redecl) {
  assert(!getObjCMethodRedeclaration(MD) && "MD already has a redeclaration");
  ObjCMethodRedecls[MD] = Redecl;
}
 
const ObjCInterfaceDecl *ASTContext::getObjContainingInterface(
                                              const NamedDecl *ND) const {
  if (const auto *ID = dyn_cast<ObjCInterfaceDecl>(ND->getDeclContext()))
    return ID;
  if (const auto *CD = dyn_cast<ObjCCategoryDecl>(ND->getDeclContext()))
    return CD->getClassInterface();
  if (const auto *IMD = dyn_cast<ObjCImplDecl>(ND->getDeclContext()))
    return IMD->getClassInterface();
 
  return nullptr;
}
 
/// Get the copy initialization expression of VarDecl, or nullptr if
/// none exists.
BlockVarCopyInit ASTContext::getBlockVarCopyInit(const VarDecl *VD) const {
  assert(VD && "Passed null params");
  assert(VD->hasAttr<BlocksAttr>() &&
         "getBlockVarCopyInits - not __block var");
  auto I = BlockVarCopyInits.find(VD);
  if (I != BlockVarCopyInits.end())
    return I->second;
  return {nullptr, false};
}
 
/// Set the copy initialization expression of a block var decl.
void ASTContext::setBlockVarCopyInit(const VarDecl*VD, Expr *CopyExpr,
                                     bool CanThrow) {
  assert(VD && CopyExpr && "Passed null params");
  assert(VD->hasAttr<BlocksAttr>() &&
         "setBlockVarCopyInits - not __block var");
  BlockVarCopyInits[VD].setExprAndFlag(CopyExpr, CanThrow);
}
 
TypeSourceInfo *ASTContext::CreateTypeSourceInfo(QualType T,
                                                 unsigned DataSize) const {
  if (!DataSize)
    DataSize = TypeLoc::getFullDataSizeForType(T);
  else
    assert(DataSize == TypeLoc::getFullDataSizeForType(T) &&
           "incorrect data size provided to CreateTypeSourceInfo!");
 
  auto *TInfo =
    (TypeSourceInfo*)BumpAlloc.Allocate(sizeof(TypeSourceInfo) + DataSize, 8);
  new (TInfo) TypeSourceInfo(T, DataSize);
  return TInfo;
}
 
TypeSourceInfo *ASTContext::getTrivialTypeSourceInfo(QualType T,
                                                     SourceLocation L) const {
  TypeSourceInfo *DI = CreateTypeSourceInfo(T);
  DI->getTypeLoc().initialize(const_cast<ASTContext &>(*this), L);
  return DI;
}
 
const ASTRecordLayout &
ASTContext::getASTObjCInterfaceLayout(const ObjCInterfaceDecl *D) const {
  return getObjCLayout(D, nullptr);
}
 
const ASTRecordLayout &
ASTContext::getASTObjCImplementationLayout(
                                        const ObjCImplementationDecl *D) const {
  return getObjCLayout(D->getClassInterface(), D);
}
 
static auto getCanonicalTemplateArguments(const ASTContext &C,
                                          ArrayRef<TemplateArgument> Args,
                                          bool &AnyNonCanonArgs) {
  SmallVector<TemplateArgument, 16> CanonArgs(Args);
  for (auto &Arg : CanonArgs) {
    TemplateArgument OrigArg = Arg;
    Arg = C.getCanonicalTemplateArgument(Arg);
    AnyNonCanonArgs |= !Arg.structurallyEquals(OrigArg);
  }
  return CanonArgs;
}
 
//===----------------------------------------------------------------------===//
//                   Type creation/memoization methods
//===----------------------------------------------------------------------===//
 
QualType
ASTContext::getExtQualType(const Type *baseType, Qualifiers quals) const {
  unsigned fastQuals = quals.getFastQualifiers();
  quals.removeFastQualifiers();
 
  // Check if we've already instantiated this type.
  llvm::FoldingSetNodeID ID;
  ExtQuals::Profile(ID, baseType, quals);
  void *insertPos = nullptr;
  if (ExtQuals *eq = ExtQualNodes.FindNodeOrInsertPos(ID, insertPos)) {
    assert(eq->getQualifiers() == quals);
    return QualType(eq, fastQuals);
  }
 
  // If the base type is not canonical, make the appropriate canonical type.
  QualType canon;
  if (!baseType->isCanonicalUnqualified()) {
    SplitQualType canonSplit = baseType->getCanonicalTypeInternal().split();
    canonSplit.Quals.addConsistentQualifiers(quals);
    canon = getExtQualType(canonSplit.Ty, canonSplit.Quals);
 
    // Re-find the insert position.
    (void) ExtQualNodes.FindNodeOrInsertPos(ID, insertPos);
  }
 
  auto *eq = new (*this, TypeAlignment) ExtQuals(baseType, canon, quals);
  ExtQualNodes.InsertNode(eq, insertPos);
  return QualType(eq, fastQuals);
}
 
QualType ASTContext::getAddrSpaceQualType(QualType T,
                                          LangAS AddressSpace) const {
  QualType CanT = getCanonicalType(T);
  if (CanT.getAddressSpace() == AddressSpace)
    return T;
 
  // If we are composing extended qualifiers together, merge together
  // into one ExtQuals node.
  QualifierCollector Quals;
  const Type *TypeNode = Quals.strip(T);
 
  // If this type already has an address space specified, it cannot get
  // another one.
  assert(!Quals.hasAddressSpace() &&
         "Type cannot be in multiple addr spaces!");
  Quals.addAddressSpace(AddressSpace);
 
  return getExtQualType(TypeNode, Quals);
}
 
QualType ASTContext::removeAddrSpaceQualType(QualType T) const {
  // If the type is not qualified with an address space, just return it
  // immediately.
  if (!T.hasAddressSpace())
    return T;
 
  // If we are composing extended qualifiers together, merge together
  // into one ExtQuals node.
  QualifierCollector Quals;
  const Type *TypeNode;
 
  while (T.hasAddressSpace()) {
    TypeNode = Quals.strip(T);
 
    // If the type no longer has an address space after stripping qualifiers,
    // jump out.
    if (!QualType(TypeNode, 0).hasAddressSpace())
      break;
 
    // There might be sugar in the way. Strip it and try again.
    T = T.getSingleStepDesugaredType(*this);
  }
 
  Quals.removeAddressSpace();
 
  // Removal of the address space can mean there are no longer any
  // non-fast qualifiers, so creating an ExtQualType isn't possible (asserts)
  // or required.
  if (Quals.hasNonFastQualifiers())
    return getExtQualType(TypeNode, Quals);
  else
    return QualType(TypeNode, Quals.getFastQualifiers());
}
 
QualType ASTContext::getObjCGCQualType(QualType T,
                                       Qualifiers::GC GCAttr) const {
  QualType CanT = getCanonicalType(T);
  if (CanT.getObjCGCAttr() == GCAttr)
    return T;
 
  if (const auto *ptr = T->getAs<PointerType>()) {
    QualType Pointee = ptr->getPointeeType();
    if (Pointee->isAnyPointerType()) {
      QualType ResultType = getObjCGCQualType(Pointee, GCAttr);
      return getPointerType(ResultType);
    }
  }
 
  // If we are composing extended qualifiers together, merge together
  // into one ExtQuals node.
  QualifierCollector Quals;
  const Type *TypeNode = Quals.strip(T);
 
  // If this type already has an ObjCGC specified, it cannot get
  // another one.
  assert(!Quals.hasObjCGCAttr() &&
         "Type cannot have multiple ObjCGCs!");
  Quals.addObjCGCAttr(GCAttr);
 
  return getExtQualType(TypeNode, Quals);
}
 
QualType ASTContext::removePtrSizeAddrSpace(QualType T) const {
  if (const PointerType *Ptr = T->getAs<PointerType>()) {
    QualType Pointee = Ptr->getPointeeType();
    if (isPtrSizeAddressSpace(Pointee.getAddressSpace())) {
      return getPointerType(removeAddrSpaceQualType(Pointee));
    }
  }
  return T;
}
 
const FunctionType *ASTContext::adjustFunctionType(const FunctionType *T,
                                                   FunctionType::ExtInfo Info) {
  if (T->getExtInfo() == Info)
    return T;
 
  QualType Result;
  if (const auto *FNPT = dyn_cast<FunctionNoProtoType>(T)) {
    Result = getFunctionNoProtoType(FNPT->getReturnType(), Info);
  } else {
    const auto *FPT = cast<FunctionProtoType>(T);
    FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
    EPI.ExtInfo = Info;
    Result = getFunctionType(FPT->getReturnType(), FPT->getParamTypes(), EPI);
  }
 
  return cast<FunctionType>(Result.getTypePtr());
}
 
void ASTContext::adjustDeducedFunctionResultType(FunctionDecl *FD,
                                                 QualType ResultType) {
  FD = FD->getMostRecentDecl();
  while (true) {
    const auto *FPT = FD->getType()->castAs<FunctionProtoType>();
    FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
    FD->setType(getFunctionType(ResultType, FPT->getParamTypes(), EPI));
    if (FunctionDecl *Next = FD->getPreviousDecl())
      FD = Next;
    else
      break;
  }
  if (ASTMutationListener *L = getASTMutationListener())
    L->DeducedReturnType(FD, ResultType);
}
 
/// Get a function type and produce the equivalent function type with the
/// specified exception specification. Type sugar that can be present on a
/// declaration of a function with an exception specification is permitted
/// and preserved. Other type sugar (for instance, typedefs) is not.
QualType ASTContext::getFunctionTypeWithExceptionSpec(
    QualType Orig, const FunctionProtoType::ExceptionSpecInfo &ESI) const {
  // Might have some parens.
  if (const auto *PT = dyn_cast<ParenType>(Orig))
    return getParenType(
        getFunctionTypeWithExceptionSpec(PT->getInnerType(), ESI));
 
  // Might be wrapped in a macro qualified type.
  if (const auto *MQT = dyn_cast<MacroQualifiedType>(Orig))
    return getMacroQualifiedType(
        getFunctionTypeWithExceptionSpec(MQT->getUnderlyingType(), ESI),
        MQT->getMacroIdentifier());
 
  // Might have a calling-convention attribute.
  if (const auto *AT = dyn_cast<AttributedType>(Orig))
    return getAttributedType(
        AT->getAttrKind(),
        getFunctionTypeWithExceptionSpec(AT->getModifiedType(), ESI),
        getFunctionTypeWithExceptionSpec(AT->getEquivalentType(), ESI));
 
  // Anything else must be a function type. Rebuild it with the new exception
  // specification.
  const auto *Proto = Orig->castAs<FunctionProtoType>();
  return getFunctionType(
      Proto->getReturnType(), Proto->getParamTypes(),
      Proto->getExtProtoInfo().withExceptionSpec(ESI));
}
 
bool ASTContext::hasSameFunctionTypeIgnoringExceptionSpec(QualType T,
                                                          QualType U) const {
  return hasSameType(T, U) ||
         (getLangOpts().CPlusPlus17 &&
          hasSameType(getFunctionTypeWithExceptionSpec(T, EST_None),
                      getFunctionTypeWithExceptionSpec(U, EST_None)));
}
 
QualType ASTContext::getFunctionTypeWithoutPtrSizes(QualType T) {
  if (const auto *Proto = T->getAs<FunctionProtoType>()) {
    QualType RetTy = removePtrSizeAddrSpace(Proto->getReturnType());
    SmallVector<QualType, 16> Args(Proto->param_types().size());
    for (unsigned i = 0, n = Args.size(); i != n; ++i)
      Args[i] = removePtrSizeAddrSpace(Proto->param_types()[i]);
    return getFunctionType(RetTy, Args, Proto->getExtProtoInfo());
  }
 
  if (const FunctionNoProtoType *Proto = T->getAs<FunctionNoProtoType>()) {
    QualType RetTy = removePtrSizeAddrSpace(Proto->getReturnType());
    return getFunctionNoProtoType(RetTy, Proto->getExtInfo());
  }
 
  return T;
}
 
bool ASTContext::hasSameFunctionTypeIgnoringPtrSizes(QualType T, QualType U) {
  return hasSameType(T, U) ||
         hasSameType(getFunctionTypeWithoutPtrSizes(T),
                     getFunctionTypeWithoutPtrSizes(U));
}
 
void ASTContext::adjustExceptionSpec(
    FunctionDecl *FD, const FunctionProtoType::ExceptionSpecInfo &ESI,
    bool AsWritten) {
  // Update the type.
  QualType Updated =
      getFunctionTypeWithExceptionSpec(FD->getType(), ESI);
  FD->setType(Updated);
 
  if (!AsWritten)
    return;
 
  // Update the type in the type source information too.
  if (TypeSourceInfo *TSInfo = FD->getTypeSourceInfo()) {
    // If the type and the type-as-written differ, we may need to update
    // the type-as-written too.
    if (TSInfo->getType() != FD->getType())
      Updated = getFunctionTypeWithExceptionSpec(TSInfo->getType(), ESI);
 
    // FIXME: When we get proper type location information for exceptions,
    // we'll also have to rebuild the TypeSourceInfo. For now, we just patch
    // up the TypeSourceInfo;
    assert(TypeLoc::getFullDataSizeForType(Updated) ==
               TypeLoc::getFullDataSizeForType(TSInfo->getType()) &&
           "TypeLoc size mismatch from updating exception specification");
    TSInfo->overrideType(Updated);
  }
}
 
/// getComplexType - Return the uniqued reference to the type for a complex
/// number with the specified element type.
QualType ASTContext::getComplexType(QualType T) const {
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  ComplexType::Profile(ID, T);
 
  void *InsertPos = nullptr;
  if (ComplexType *CT = ComplexTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(CT, 0);
 
  // If the pointee type isn't canonical, this won't be a canonical type either,
  // so fill in the canonical type field.
  QualType Canonical;
  if (!T.isCanonical()) {
    Canonical = getComplexType(getCanonicalType(T));
 
    // Get the new insert position for the node we care about.
    ComplexType *NewIP = ComplexTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  auto *New = new (*this, TypeAlignment) ComplexType(T, Canonical);
  Types.push_back(New);
  ComplexTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
/// getPointerType - Return the uniqued reference to the type for a pointer to
/// the specified type.
QualType ASTContext::getPointerType(QualType T) const {
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  PointerType::Profile(ID, T);
 
  void *InsertPos = nullptr;
  if (PointerType *PT = PointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(PT, 0);
 
  // If the pointee type isn't canonical, this won't be a canonical type either,
  // so fill in the canonical type field.
  QualType Canonical;
  if (!T.isCanonical()) {
    Canonical = getPointerType(getCanonicalType(T));
 
    // Get the new insert position for the node we care about.
    PointerType *NewIP = PointerTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  auto *New = new (*this, TypeAlignment) PointerType(T, Canonical);
  Types.push_back(New);
  PointerTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
QualType ASTContext::getAdjustedType(QualType Orig, QualType New) const {
  llvm::FoldingSetNodeID ID;
  AdjustedType::Profile(ID, Orig, New);
  void *InsertPos = nullptr;
  AdjustedType *AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (AT)
    return QualType(AT, 0);
 
  QualType Canonical = getCanonicalType(New);
 
  // Get the new insert position for the node we care about.
  AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  assert(!AT && "Shouldn't be in the map!");
 
  AT = new (*this, TypeAlignment)
      AdjustedType(Type::Adjusted, Orig, New, Canonical);
  Types.push_back(AT);
  AdjustedTypes.InsertNode(AT, InsertPos);
  return QualType(AT, 0);
}
 
QualType ASTContext::getDecayedType(QualType Orig, QualType Decayed) const {
  llvm::FoldingSetNodeID ID;
  AdjustedType::Profile(ID, Orig, Decayed);
  void *InsertPos = nullptr;
  AdjustedType *AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (AT)
    return QualType(AT, 0);
 
  QualType Canonical = getCanonicalType(Decayed);
 
  // Get the new insert position for the node we care about.
  AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  assert(!AT && "Shouldn't be in the map!");
 
  AT = new (*this, TypeAlignment) DecayedType(Orig, Decayed, Canonical);
  Types.push_back(AT);
  AdjustedTypes.InsertNode(AT, InsertPos);
  return QualType(AT, 0);
}
 
QualType ASTContext::getDecayedType(QualType T) const {
  assert((T->isArrayType() || T->isFunctionType()) && "T does not decay");
 
  QualType Decayed;
 
  // C99 6.7.5.3p7:
  //   A declaration of a parameter as "array of type" shall be
  //   adjusted to "qualified pointer to type", where the type
  //   qualifiers (if any) are those specified within the [ and ] of
  //   the array type derivation.
  if (T->isArrayType())
    Decayed = getArrayDecayedType(T);
 
  // C99 6.7.5.3p8:
  //   A declaration of a parameter as "function returning type"
  //   shall be adjusted to "pointer to function returning type", as
  //   in 6.3.2.1.
  if (T->isFunctionType())
    Decayed = getPointerType(T);
 
  return getDecayedType(T, Decayed);
}
 
/// getBlockPointerType - Return the uniqued reference to the type for
/// a pointer to the specified block.
QualType ASTContext::getBlockPointerType(QualType T) const {
  assert(T->isFunctionType() && "block of function types only");
  // Unique pointers, to guarantee there is only one block of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  BlockPointerType::Profile(ID, T);
 
  void *InsertPos = nullptr;
  if (BlockPointerType *PT =
        BlockPointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(PT, 0);
 
  // If the block pointee type isn't canonical, this won't be a canonical
  // type either so fill in the canonical type field.
  QualType Canonical;
  if (!T.isCanonical()) {
    Canonical = getBlockPointerType(getCanonicalType(T));
 
    // Get the new insert position for the node we care about.
    BlockPointerType *NewIP =
      BlockPointerTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  auto *New = new (*this, TypeAlignment) BlockPointerType(T, Canonical);
  Types.push_back(New);
  BlockPointerTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
/// getLValueReferenceType - Return the uniqued reference to the type for an
/// lvalue reference to the specified type.
QualType
ASTContext::getLValueReferenceType(QualType T, bool SpelledAsLValue) const {
  assert((!T->isPlaceholderType() ||
          T->isSpecificPlaceholderType(BuiltinType::UnknownAny)) &&
         "Unresolved placeholder type");
 
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  ReferenceType::Profile(ID, T, SpelledAsLValue);
 
  void *InsertPos = nullptr;
  if (LValueReferenceType *RT =
        LValueReferenceTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(RT, 0);
 
  const auto *InnerRef = T->getAs<ReferenceType>();
 
  // If the referencee type isn't canonical, this won't be a canonical type
  // either, so fill in the canonical type field.
  QualType Canonical;
  if (!SpelledAsLValue || InnerRef || !T.isCanonical()) {
    QualType PointeeType = (InnerRef ? InnerRef->getPointeeType() : T);
    Canonical = getLValueReferenceType(getCanonicalType(PointeeType));
 
    // Get the new insert position for the node we care about.
    LValueReferenceType *NewIP =
      LValueReferenceTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
 
  auto *New = new (*this, TypeAlignment) LValueReferenceType(T, Canonical,
                                                             SpelledAsLValue);
  Types.push_back(New);
  LValueReferenceTypes.InsertNode(New, InsertPos);
 
  return QualType(New, 0);
}
 
/// getRValueReferenceType - Return the uniqued reference to the type for an
/// rvalue reference to the specified type.
QualType ASTContext::getRValueReferenceType(QualType T) const {
  assert((!T->isPlaceholderType() ||
          T->isSpecificPlaceholderType(BuiltinType::UnknownAny)) &&
         "Unresolved placeholder type");
 
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  ReferenceType::Profile(ID, T, false);
 
  void *InsertPos = nullptr;
  if (RValueReferenceType *RT =
        RValueReferenceTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(RT, 0);
 
  const auto *InnerRef = T->getAs<ReferenceType>();
 
  // If the referencee type isn't canonical, this won't be a canonical type
  // either, so fill in the canonical type field.
  QualType Canonical;
  if (InnerRef || !T.isCanonical()) {
    QualType PointeeType = (InnerRef ? InnerRef->getPointeeType() : T);
    Canonical = getRValueReferenceType(getCanonicalType(PointeeType));
 
    // Get the new insert position for the node we care about.
    RValueReferenceType *NewIP =
      RValueReferenceTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
 
  auto *New = new (*this, TypeAlignment) RValueReferenceType(T, Canonical);
  Types.push_back(New);
  RValueReferenceTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
/// getMemberPointerType - Return the uniqued reference to the type for a
/// member pointer to the specified type, in the specified class.
QualType ASTContext::getMemberPointerType(QualType T, const Type *Cls) const {
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  MemberPointerType::Profile(ID, T, Cls);
 
  void *InsertPos = nullptr;
  if (MemberPointerType *PT =
      MemberPointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(PT, 0);
 
  // If the pointee or class type isn't canonical, this won't be a canonical
  // type either, so fill in the canonical type field.
  QualType Canonical;
  if (!T.isCanonical() || !Cls->isCanonicalUnqualified()) {
    Canonical = getMemberPointerType(getCanonicalType(T),getCanonicalType(Cls));
 
    // Get the new insert position for the node we care about.
    MemberPointerType *NewIP =
      MemberPointerTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  auto *New = new (*this, TypeAlignment) MemberPointerType(T, Cls, Canonical);
  Types.push_back(New);
  MemberPointerTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
/// getConstantArrayType - Return the unique reference to the type for an
/// array of the specified element type.
QualType ASTContext::getConstantArrayType(QualType EltTy,
                                          const llvm::APInt &ArySizeIn,
                                          const Expr *SizeExpr,
                                          ArrayType::ArraySizeModifier ASM,
                                          unsigned IndexTypeQuals) const {
  assert((EltTy->isDependentType() ||
          EltTy->isIncompleteType() || EltTy->isConstantSizeType()) &&
         "Constant array of VLAs is illegal!");
 
  // We only need the size as part of the type if it's instantiation-dependent.
  if (SizeExpr && !SizeExpr->isInstantiationDependent())
    SizeExpr = nullptr;
 
  // Convert the array size into a canonical width matching the pointer size for
  // the target.
  llvm::APInt ArySize(ArySizeIn);
  ArySize = ArySize.zextOrTrunc(Target->getMaxPointerWidth());
 
  llvm::FoldingSetNodeID ID;
  ConstantArrayType::Profile(ID, *this, EltTy, ArySize, SizeExpr, ASM,
                             IndexTypeQuals);
 
  void *InsertPos = nullptr;
  if (ConstantArrayType *ATP =
      ConstantArrayTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(ATP, 0);
 
  // If the element type isn't canonical or has qualifiers, or the array bound
  // is instantiation-dependent, this won't be a canonical type either, so fill
  // in the canonical type field.
  QualType Canon;
  // FIXME: Check below should look for qualifiers behind sugar.
  if (!EltTy.isCanonical() || EltTy.hasLocalQualifiers() || SizeExpr) {
    SplitQualType canonSplit = getCanonicalType(EltTy).split();
    Canon = getConstantArrayType(QualType(canonSplit.Ty, 0), ArySize, nullptr,
                                 ASM, IndexTypeQuals);
    Canon = getQualifiedType(Canon, canonSplit.Quals);
 
    // Get the new insert position for the node we care about.
    ConstantArrayType *NewIP =
      ConstantArrayTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
 
  void *Mem = Allocate(
      ConstantArrayType::totalSizeToAlloc<const Expr *>(SizeExpr ? 1 : 0),
      TypeAlignment);
  auto *New = new (Mem)
    ConstantArrayType(EltTy, Canon, ArySize, SizeExpr, ASM, IndexTypeQuals);
  ConstantArrayTypes.InsertNode(New, InsertPos);
  Types.push_back(New);
  return QualType(New, 0);
}
 
/// getVariableArrayDecayedType - Turns the given type, which may be
/// variably-modified, into the corresponding type with all the known
/// sizes replaced with [*].
QualType ASTContext::getVariableArrayDecayedType(QualType type) const {
  // Vastly most common case.
  if (!type->isVariablyModifiedType()) return type;
 
  QualType result;
 
  SplitQualType split = type.getSplitDesugaredType();
  const Type *ty = split.Ty;
  switch (ty->getTypeClass()) {
#define TYPE(Class, Base)
#define ABSTRACT_TYPE(Class, Base)
#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
#include "clang/AST/TypeNodes.inc"
    llvm_unreachable("didn't desugar past all non-canonical types?");
 
  // These types should never be variably-modified.
  case Type::Builtin:
  case Type::Complex:
  case Type::Vector:
  case Type::DependentVector:
  case Type::ExtVector:
  case Type::DependentSizedExtVector:
  case Type::ConstantMatrix:
  case Type::DependentSizedMatrix:
  case Type::DependentAddressSpace:
  case Type::ObjCObject:
  case Type::ObjCInterface:
  case Type::ObjCObjectPointer:
  case Type::Record:
  case Type::Enum:
  case Type::UnresolvedUsing:
  case Type::TypeOfExpr:
  case Type::TypeOf:
  case Type::Decltype:
  case Type::UnaryTransform:
  case Type::DependentName:
  case Type::InjectedClassName:
  case Type::TemplateSpecialization:
  case Type::DependentTemplateSpecialization:
  case Type::TemplateTypeParm:
  case Type::SubstTemplateTypeParmPack:
  case Type::Auto:
  case Type::DeducedTemplateSpecialization:
  case Type::PackExpansion:
  case Type::BitInt:
  case Type::DependentBitInt:
    llvm_unreachable("type should never be variably-modified");
 
  // These types can be variably-modified but should never need to
  // further decay.
  case Type::FunctionNoProto:
  case Type::FunctionProto:
  case Type::BlockPointer:
  case Type::MemberPointer:
  case Type::Pipe:
    return type;
 
  // These types can be variably-modified.  All these modifications
  // preserve structure except as noted by comments.
  // TODO: if we ever care about optimizing VLAs, there are no-op
  // optimizations available here.
  case Type::Pointer:
    result = getPointerType(getVariableArrayDecayedType(
                              cast<PointerType>(ty)->getPointeeType()));
    break;
 
  case Type::LValueReference: {
    const auto *lv = cast<LValueReferenceType>(ty);
    result = getLValueReferenceType(
                 getVariableArrayDecayedType(lv->getPointeeType()),
                                    lv->isSpelledAsLValue());
    break;
  }
 
  case Type::RValueReference: {
    const auto *lv = cast<RValueReferenceType>(ty);
    result = getRValueReferenceType(
                 getVariableArrayDecayedType(lv->getPointeeType()));
    break;
  }
 
  case Type::Atomic: {
    const auto *at = cast<AtomicType>(ty);
    result = getAtomicType(getVariableArrayDecayedType(at->getValueType()));
    break;
  }
 
  case Type::ConstantArray: {
    const auto *cat = cast<ConstantArrayType>(ty);
    result = getConstantArrayType(
                 getVariableArrayDecayedType(cat->getElementType()),
                                  cat->getSize(),
                                  cat->getSizeExpr(),
                                  cat->getSizeModifier(),
                                  cat->getIndexTypeCVRQualifiers());
    break;
  }
 
  case Type::DependentSizedArray: {
    const auto *dat = cast<DependentSizedArrayType>(ty);
    result = getDependentSizedArrayType(
                 getVariableArrayDecayedType(dat->getElementType()),
                                        dat->getSizeExpr(),
                                        dat->getSizeModifier(),
                                        dat->getIndexTypeCVRQualifiers(),
                                        dat->getBracketsRange());
    break;
  }
 
  // Turn incomplete types into [*] types.
  case Type::IncompleteArray: {
    const auto *iat = cast<IncompleteArrayType>(ty);
    result = getVariableArrayType(
                 getVariableArrayDecayedType(iat->getElementType()),
                                  /*size*/ nullptr,
                                  ArrayType::Normal,
                                  iat->getIndexTypeCVRQualifiers(),
                                  SourceRange());
    break;
  }
 
  // Turn VLA types into [*] types.
  case Type::VariableArray: {
    const auto *vat = cast<VariableArrayType>(ty);
    result = getVariableArrayType(
                 getVariableArrayDecayedType(vat->getElementType()),
                                  /*size*/ nullptr,
                                  ArrayType::Star,
                                  vat->getIndexTypeCVRQualifiers(),
                                  vat->getBracketsRange());
    break;
  }
  }
 
  // Apply the top-level qualifiers from the original.
  return getQualifiedType(result, split.Quals);
}
 
/// getVariableArrayType - Returns a non-unique reference to the type for a
/// variable array of the specified element type.
QualType ASTContext::getVariableArrayType(QualType EltTy,
                                          Expr *NumElts,
                                          ArrayType::ArraySizeModifier ASM,
                                          unsigned IndexTypeQuals,
                                          SourceRange Brackets) const {
  // Since we don't unique expressions, it isn't possible to unique VLA's
  // that have an expression provided for their size.
  QualType Canon;
 
  // Be sure to pull qualifiers off the element type.
  // FIXME: Check below should look for qualifiers behind sugar.
  if (!EltTy.isCanonical() || EltTy.hasLocalQualifiers()) {
    SplitQualType canonSplit = getCanonicalType(EltTy).split();
    Canon = getVariableArrayType(QualType(canonSplit.Ty, 0), NumElts, ASM,
                                 IndexTypeQuals, Brackets);
    Canon = getQualifiedType(Canon, canonSplit.Quals);
  }
 
  auto *New = new (*this, TypeAlignment)
    VariableArrayType(EltTy, Canon, NumElts, ASM, IndexTypeQuals, Brackets);
 
  VariableArrayTypes.push_back(New);
  Types.push_back(New);
  return QualType(New, 0);
}
 
/// getDependentSizedArrayType - Returns a non-unique reference to
/// the type for a dependently-sized array of the specified element
/// type.
QualType ASTContext::getDependentSizedArrayType(QualType elementType,
                                                Expr *numElements,
                                                ArrayType::ArraySizeModifier ASM,
                                                unsigned elementTypeQuals,
                                                SourceRange brackets) const {
  assert((!numElements || numElements->isTypeDependent() ||
          numElements->isValueDependent()) &&
         "Size must be type- or value-dependent!");
 
  // Dependently-sized array types that do not have a specified number
  // of elements will have their sizes deduced from a dependent
  // initializer.  We do no canonicalization here at all, which is okay
  // because they can't be used in most locations.
  if (!numElements) {
    auto *newType
      = new (*this, TypeAlignment)
          DependentSizedArrayType(*this, elementType, QualType(),
                                  numElements, ASM, elementTypeQuals,
                                  brackets);
    Types.push_back(newType);
    return QualType(newType, 0);
  }
 
  // Otherwise, we actually build a new type every time, but we
  // also build a canonical type.
 
  SplitQualType canonElementType = getCanonicalType(elementType).split();
 
  void *insertPos = nullptr;
  llvm::FoldingSetNodeID ID;
  DependentSizedArrayType::Profile(ID, *this,
                                   QualType(canonElementType.Ty, 0),
                                   ASM, elementTypeQuals, numElements);
 
  // Look for an existing type with these properties.
  DependentSizedArrayType *canonTy =
    DependentSizedArrayTypes.FindNodeOrInsertPos(ID, insertPos);
 
  // If we don't have one, build one.
  if (!canonTy) {
    canonTy = new (*this, TypeAlignment)
      DependentSizedArrayType(*this, QualType(canonElementType.Ty, 0),
                              QualType(), numElements, ASM, elementTypeQuals,
                              brackets);
    DependentSizedArrayTypes.InsertNode(canonTy, insertPos);
    Types.push_back(canonTy);
  }
 
  // Apply qualifiers from the element type to the array.
  QualType canon = getQualifiedType(QualType(canonTy,0),
                                    canonElementType.Quals);
 
  // If we didn't need extra canonicalization for the element type or the size
  // expression, then just use that as our result.
  if (QualType(canonElementType.Ty, 0) == elementType &&
      canonTy->getSizeExpr() == numElements)
    return canon;
 
  // Otherwise, we need to build a type which follows the spelling
  // of the element type.
  auto *sugaredType
    = new (*this, TypeAlignment)
        DependentSizedArrayType(*this, elementType, canon, numElements,
                                ASM, elementTypeQuals, brackets);
  Types.push_back(sugaredType);
  return QualType(sugaredType, 0);
}
 
QualType ASTContext::getIncompleteArrayType(QualType elementType,
                                            ArrayType::ArraySizeModifier ASM,
                                            unsigned elementTypeQuals) const {
  llvm::FoldingSetNodeID ID;
  IncompleteArrayType::Profile(ID, elementType, ASM, elementTypeQuals);
 
  void *insertPos = nullptr;
  if (IncompleteArrayType *iat =
       IncompleteArrayTypes.FindNodeOrInsertPos(ID, insertPos))
    return QualType(iat, 0);
 
  // If the element type isn't canonical, this won't be a canonical type
  // either, so fill in the canonical type field.  We also have to pull
  // qualifiers off the element type.
  QualType canon;
 
  // FIXME: Check below should look for qualifiers behind sugar.
  if (!elementType.isCanonical() || elementType.hasLocalQualifiers()) {
    SplitQualType canonSplit = getCanonicalType(elementType).split();
    canon = getIncompleteArrayType(QualType(canonSplit.Ty, 0),
                                   ASM, elementTypeQuals);
    canon = getQualifiedType(canon, canonSplit.Quals);
 
    // Get the new insert position for the node we care about.
    IncompleteArrayType *existing =
      IncompleteArrayTypes.FindNodeOrInsertPos(ID, insertPos);
    assert(!existing && "Shouldn't be in the map!"); (void) existing;
  }
 
  auto *newType = new (*this, TypeAlignment)
    IncompleteArrayType(elementType, canon, ASM, elementTypeQuals);
 
  IncompleteArrayTypes.InsertNode(newType, insertPos);
  Types.push_back(newType);
  return QualType(newType, 0);
}
 
ASTContext::BuiltinVectorTypeInfo
ASTContext::getBuiltinVectorTypeInfo(const BuiltinType *Ty) const {
#define SVE_INT_ELTTY(BITS, ELTS, SIGNED, NUMVECTORS)                          \
  {getIntTypeForBitwidth(BITS, SIGNED), llvm::ElementCount::getScalable(ELTS), \
   NUMVECTORS};
 
#define SVE_ELTTY(ELTTY, ELTS, NUMVECTORS)                                     \
  {ELTTY, llvm::ElementCount::getScalable(ELTS), NUMVECTORS};
 
  switch (Ty->getKind()) {
  default:
    llvm_unreachable("Unsupported builtin vector type");
  case BuiltinType::SveInt8:
    return SVE_INT_ELTTY(8, 16, true, 1);
  case BuiltinType::SveUint8:
    return SVE_INT_ELTTY(8, 16, false, 1);
  case BuiltinType::SveInt8x2:
    return SVE_INT_ELTTY(8, 16, true, 2);
  case BuiltinType::SveUint8x2:
    return SVE_INT_ELTTY(8, 16, false, 2);
  case BuiltinType::SveInt8x3:
    return SVE_INT_ELTTY(8, 16, true, 3);
  case BuiltinType::SveUint8x3:
    return SVE_INT_ELTTY(8, 16, false, 3);
  case BuiltinType::SveInt8x4:
    return SVE_INT_ELTTY(8, 16, true, 4);
  case BuiltinType::SveUint8x4:
    return SVE_INT_ELTTY(8, 16, false, 4);
  case BuiltinType::SveInt16:
    return SVE_INT_ELTTY(16, 8, true, 1);
  case BuiltinType::SveUint16:
    return SVE_INT_ELTTY(16, 8, false, 1);
  case BuiltinType::SveInt16x2:
    return SVE_INT_ELTTY(16, 8, true, 2);
  case BuiltinType::SveUint16x2:
    return SVE_INT_ELTTY(16, 8, false, 2);
  case BuiltinType::SveInt16x3:
    return SVE_INT_ELTTY(16, 8, true, 3);
  case BuiltinType::SveUint16x3:
    return SVE_INT_ELTTY(16, 8, false, 3);
  case BuiltinType::SveInt16x4:
    return SVE_INT_ELTTY(16, 8, true, 4);
  case BuiltinType::SveUint16x4:
    return SVE_INT_ELTTY(16, 8, false, 4);
  case BuiltinType::SveInt32:
    return SVE_INT_ELTTY(32, 4, true, 1);
  case BuiltinType::SveUint32:
    return SVE_INT_ELTTY(32, 4, false, 1);
  case BuiltinType::SveInt32x2:
    return SVE_INT_ELTTY(32, 4, true, 2);
  case BuiltinType::SveUint32x2:
    return SVE_INT_ELTTY(32, 4, false, 2);
  case BuiltinType::SveInt32x3:
    return SVE_INT_ELTTY(32, 4, true, 3);
  case BuiltinType::SveUint32x3:
    return SVE_INT_ELTTY(32, 4, false, 3);
  case BuiltinType::SveInt32x4:
    return SVE_INT_ELTTY(32, 4, true, 4);
  case BuiltinType::SveUint32x4:
    return SVE_INT_ELTTY(32, 4, false, 4);
  case BuiltinType::SveInt64:
    return SVE_INT_ELTTY(64, 2, true, 1);
  case BuiltinType::SveUint64:
    return SVE_INT_ELTTY(64, 2, false, 1);
  case BuiltinType::SveInt64x2:
    return SVE_INT_ELTTY(64, 2, true, 2);
  case BuiltinType::SveUint64x2:
    return SVE_INT_ELTTY(64, 2, false, 2);
  case BuiltinType::SveInt64x3:
    return SVE_INT_ELTTY(64, 2, true, 3);
  case BuiltinType::SveUint64x3:
    return SVE_INT_ELTTY(64, 2, false, 3);
  case BuiltinType::SveInt64x4:
    return SVE_INT_ELTTY(64, 2, true, 4);
  case BuiltinType::SveUint64x4:
    return SVE_INT_ELTTY(64, 2, false, 4);
  case BuiltinType::SveBool:
    return SVE_ELTTY(BoolTy, 16, 1);
  case BuiltinType::SveBoolx2:
    return SVE_ELTTY(BoolTy, 16, 2);
  case BuiltinType::SveBoolx4:
    return SVE_ELTTY(BoolTy, 16, 4);
  case BuiltinType::SveFloat16:
    return SVE_ELTTY(HalfTy, 8, 1);
  case BuiltinType::SveFloat16x2:
    return SVE_ELTTY(HalfTy, 8, 2);
  case BuiltinType::SveFloat16x3:
    return SVE_ELTTY(HalfTy, 8, 3);
  case BuiltinType::SveFloat16x4:
    return SVE_ELTTY(HalfTy, 8, 4);
  case BuiltinType::SveFloat32:
    return SVE_ELTTY(FloatTy, 4, 1);
  case BuiltinType::SveFloat32x2:
    return SVE_ELTTY(FloatTy, 4, 2);
  case BuiltinType::SveFloat32x3:
    return SVE_ELTTY(FloatTy, 4, 3);
  case BuiltinType::SveFloat32x4:
    return SVE_ELTTY(FloatTy, 4, 4);
  case BuiltinType::SveFloat64:
    return SVE_ELTTY(DoubleTy, 2, 1);
  case BuiltinType::SveFloat64x2:
    return SVE_ELTTY(DoubleTy, 2, 2);
  case BuiltinType::SveFloat64x3:
    return SVE_ELTTY(DoubleTy, 2, 3);
  case BuiltinType::SveFloat64x4:
    return SVE_ELTTY(DoubleTy, 2, 4);
  case BuiltinType::SveBFloat16:
    return SVE_ELTTY(BFloat16Ty, 8, 1);
  case BuiltinType::SveBFloat16x2:
    return SVE_ELTTY(BFloat16Ty, 8, 2);
  case BuiltinType::SveBFloat16x3:
    return SVE_ELTTY(BFloat16Ty, 8, 3);
  case BuiltinType::SveBFloat16x4:
    return SVE_ELTTY(BFloat16Ty, 8, 4);
#define RVV_VECTOR_TYPE_INT(Name, Id, SingletonId, NumEls, ElBits, NF,         \
                            IsSigned)                                          \
  case BuiltinType::Id:                                                        \
    return {getIntTypeForBitwidth(ElBits, IsSigned),                           \
            llvm::ElementCount::getScalable(NumEls), NF};
#define RVV_VECTOR_TYPE_FLOAT(Name, Id, SingletonId, NumEls, ElBits, NF)       \
  case BuiltinType::Id:                                                        \
    return {ElBits == 16 ? Float16Ty : (ElBits == 32 ? FloatTy : DoubleTy),    \
            llvm::ElementCount::getScalable(NumEls), NF};
#define RVV_PREDICATE_TYPE(Name, Id, SingletonId, NumEls)                      \
  case BuiltinType::Id:                                                        \
    return {BoolTy, llvm::ElementCount::getScalable(NumEls), 1};
#include "clang/Basic/RISCVVTypes.def"
  }
}
 
/// getExternrefType - Return a WebAssembly externref type, which represents an
/// opaque reference to a host value.
QualType ASTContext::getWebAssemblyExternrefType() const {
  if (Target->getTriple().isWasm() && Target->hasFeature("reference-types")) {
#define WASM_REF_TYPE(Name, MangledName, Id, SingletonId, AS)                  \
  if (BuiltinType::Id == BuiltinType::WasmExternRef)                           \
    return SingletonId;
#include "clang/Basic/WebAssemblyReferenceTypes.def"
  }
  llvm_unreachable(
      "shouldn't try to generate type externref outside WebAssembly target");
}
 
/// getScalableVectorType - Return the unique reference to a scalable vector
/// type of the specified element type and size. VectorType must be a built-in
/// type.
QualType ASTContext::getScalableVectorType(QualType EltTy, unsigned NumElts,
                                           unsigned NumFields) const {
  if (Target->hasAArch64SVETypes()) {
    uint64_t EltTySize = getTypeSize(EltTy);
#define SVE_VECTOR_TYPE(Name, MangledName, Id, SingletonId, NumEls, ElBits,    \
                        IsSigned, IsFP, IsBF)                                  \
  if (!EltTy->isBooleanType() &&                                               \
      ((EltTy->hasIntegerRepresentation() &&                                   \
        EltTy->hasSignedIntegerRepresentation() == IsSigned) ||                \
       (EltTy->hasFloatingRepresentation() && !EltTy->isBFloat16Type() &&      \
        IsFP && !IsBF) ||                                                      \
       (EltTy->hasFloatingRepresentation() && EltTy->isBFloat16Type() &&       \
        IsBF && !IsFP)) &&                                                     \
      EltTySize == ElBits && NumElts == NumEls) {                              \
    return SingletonId;                                                        \
  }
#define SVE_PREDICATE_TYPE(Name, MangledName, Id, SingletonId, NumEls)         \
  if (EltTy->isBooleanType() && NumElts == NumEls)                             \
    return SingletonId;
#define SVE_OPAQUE_TYPE(Name, MangledName, Id, SingleTonId)
#include "clang/Basic/AArch64SVEACLETypes.def"
  } else if (Target->hasRISCVVTypes()) {
    uint64_t EltTySize = getTypeSize(EltTy);
#define RVV_VECTOR_TYPE(Name, Id, SingletonId, NumEls, ElBits, NF, IsSigned,   \
                        IsFP)                                                  \
  if (!EltTy->isBooleanType() &&                                               \
      ((EltTy->hasIntegerRepresentation() &&                                   \
        EltTy->hasSignedIntegerRepresentation() == IsSigned) ||                \
       (EltTy->hasFloatingRepresentation() && IsFP)) &&                        \
      EltTySize == ElBits && NumElts == NumEls && NumFields == NF)             \
    return SingletonId;
#define RVV_PREDICATE_TYPE(Name, Id, SingletonId, NumEls)                      \
  if (EltTy->isBooleanType() && NumElts == NumEls)                             \
    return SingletonId;
#include "clang/Basic/RISCVVTypes.def"
  }
  return QualType();
}
 
/// getVectorType - Return the unique reference to a vector type of
/// the specified element type and size. VectorType must be a built-in type.
QualType ASTContext::getVectorType(QualType vecType, unsigned NumElts,
                                   VectorType::VectorKind VecKind) const {
  assert(vecType->isBuiltinType() ||
         (vecType->isBitIntType() &&
          // Only support _BitInt elements with byte-sized power of 2 NumBits.
          llvm::isPowerOf2_32(vecType->getAs<BitIntType>()->getNumBits()) &&
          vecType->getAs<BitIntType>()->getNumBits() >= 8));
 
  // Check if we've already instantiated a vector of this type.
  llvm::FoldingSetNodeID ID;
  VectorType::Profile(ID, vecType, NumElts, Type::Vector, VecKind);
 
  void *InsertPos = nullptr;
  if (VectorType *VTP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(VTP, 0);
 
  // If the element type isn't canonical, this won't be a canonical type either,
  // so fill in the canonical type field.
  QualType Canonical;
  if (!vecType.isCanonical()) {
    Canonical = getVectorType(getCanonicalType(vecType), NumElts, VecKind);
 
    // Get the new insert position for the node we care about.
    VectorType *NewIP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  auto *New = new (*this, TypeAlignment)
    VectorType(vecType, NumElts, Canonical, VecKind);
  VectorTypes.InsertNode(New, InsertPos);
  Types.push_back(New);
  return QualType(New, 0);
}
 
QualType
ASTContext::getDependentVectorType(QualType VecType, Expr *SizeExpr,
                                   SourceLocation AttrLoc,
                                   VectorType::VectorKind VecKind) const {
  llvm::FoldingSetNodeID ID;
  DependentVectorType::Profile(ID, *this, getCanonicalType(VecType), SizeExpr,
                               VecKind);
  void *InsertPos = nullptr;
  DependentVectorType *Canon =
      DependentVectorTypes.FindNodeOrInsertPos(ID, InsertPos);
  DependentVectorType *New;
 
  if (Canon) {
    New = new (*this, TypeAlignment) DependentVectorType(
        *this, VecType, QualType(Canon, 0), SizeExpr, AttrLoc, VecKind);
  } else {
    QualType CanonVecTy = getCanonicalType(VecType);
    if (CanonVecTy == VecType) {
      New = new (*this, TypeAlignment) DependentVectorType(
          *this, VecType, QualType(), SizeExpr, AttrLoc, VecKind);
 
      DependentVectorType *CanonCheck =
          DependentVectorTypes.FindNodeOrInsertPos(ID, InsertPos);
      assert(!CanonCheck &&
             "Dependent-sized vector_size canonical type broken");
      (void)CanonCheck;
      DependentVectorTypes.InsertNode(New, InsertPos);
    } else {
      QualType CanonTy = getDependentVectorType(CanonVecTy, SizeExpr,
                                                SourceLocation(), VecKind);
      New = new (*this, TypeAlignment) DependentVectorType(
          *this, VecType, CanonTy, SizeExpr, AttrLoc, VecKind);
    }
  }
 
  Types.push_back(New);
  return QualType(New, 0);
}
 
/// getExtVectorType - Return the unique reference to an extended vector type of
/// the specified element type and size. VectorType must be a built-in type.
QualType ASTContext::getExtVectorType(QualType vecType,
                                      unsigned NumElts) const {
  assert(vecType->isBuiltinType() || vecType->isDependentType() ||
         (vecType->isBitIntType() &&
          // Only support _BitInt elements with byte-sized power of 2 NumBits.
          llvm::isPowerOf2_32(vecType->getAs<BitIntType>()->getNumBits()) &&
          vecType->getAs<BitIntType>()->getNumBits() >= 8));
 
  // Check if we've already instantiated a vector of this type.
  llvm::FoldingSetNodeID ID;
  VectorType::Profile(ID, vecType, NumElts, Type::ExtVector,
                      VectorType::GenericVector);
  void *InsertPos = nullptr;
  if (VectorType *VTP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(VTP, 0);
 
  // If the element type isn't canonical, this won't be a canonical type either,
  // so fill in the canonical type field.
  QualType Canonical;
  if (!vecType.isCanonical()) {
    Canonical = getExtVectorType(getCanonicalType(vecType), NumElts);
 
    // Get the new insert position for the node we care about.
    VectorType *NewIP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  auto *New = new (*this, TypeAlignment)
    ExtVectorType(vecType, NumElts, Canonical);
  VectorTypes.InsertNode(New, InsertPos);
  Types.push_back(New);
  return QualType(New, 0);
}
 
QualType
ASTContext::getDependentSizedExtVectorType(QualType vecType,
                                           Expr *SizeExpr,
                                           SourceLocation AttrLoc) const {
  llvm::FoldingSetNodeID ID;
  DependentSizedExtVectorType::Profile(ID, *this, getCanonicalType(vecType),
                                       SizeExpr);
 
  void *InsertPos = nullptr;
  DependentSizedExtVectorType *Canon
    = DependentSizedExtVectorTypes.FindNodeOrInsertPos(ID, InsertPos);
  DependentSizedExtVectorType *New;
  if (Canon) {
    // We already have a canonical version of this array type; use it as
    // the canonical type for a newly-built type.
    New = new (*this, TypeAlignment)
      DependentSizedExtVectorType(*this, vecType, QualType(Canon, 0),
                                  SizeExpr, AttrLoc);
  } else {
    QualType CanonVecTy = getCanonicalType(vecType);
    if (CanonVecTy == vecType) {
      New = new (*this, TypeAlignment)
        DependentSizedExtVectorType(*this, vecType, QualType(), SizeExpr,
                                    AttrLoc);
 
      DependentSizedExtVectorType *CanonCheck
        = DependentSizedExtVectorTypes.FindNodeOrInsertPos(ID, InsertPos);
      assert(!CanonCheck && "Dependent-sized ext_vector canonical type broken");
      (void)CanonCheck;
      DependentSizedExtVectorTypes.InsertNode(New, InsertPos);
    } else {
      QualType CanonExtTy = getDependentSizedExtVectorType(CanonVecTy, SizeExpr,
                                                           SourceLocation());
      New = new (*this, TypeAlignment) DependentSizedExtVectorType(
          *this, vecType, CanonExtTy, SizeExpr, AttrLoc);
    }
  }
 
  Types.push_back(New);
  return QualType(New, 0);
}
 
QualType ASTContext::getConstantMatrixType(QualType ElementTy, unsigned NumRows,
                                           unsigned NumColumns) const {
  llvm::FoldingSetNodeID ID;
  ConstantMatrixType::Profile(ID, ElementTy, NumRows, NumColumns,
                              Type::ConstantMatrix);
 
  assert(MatrixType::isValidElementType(ElementTy) &&
         "need a valid element type");
  assert(ConstantMatrixType::isDimensionValid(NumRows) &&
         ConstantMatrixType::isDimensionValid(NumColumns) &&
         "need valid matrix dimensions");
  void *InsertPos = nullptr;
  if (ConstantMatrixType *MTP = MatrixTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(MTP, 0);
 
  QualType Canonical;
  if (!ElementTy.isCanonical()) {
    Canonical =
        getConstantMatrixType(getCanonicalType(ElementTy), NumRows, NumColumns);
 
    ConstantMatrixType *NewIP = MatrixTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Matrix type shouldn't already exist in the map");
    (void)NewIP;
  }
 
  auto *New = new (*this, TypeAlignment)
      ConstantMatrixType(ElementTy, NumRows, NumColumns, Canonical);
  MatrixTypes.InsertNode(New, InsertPos);
  Types.push_back(New);
  return QualType(New, 0);
}
 
QualType ASTContext::getDependentSizedMatrixType(QualType ElementTy,
                                                 Expr *RowExpr,
                                                 Expr *ColumnExpr,
                                                 SourceLocation AttrLoc) const {
  QualType CanonElementTy = getCanonicalType(ElementTy);
  llvm::FoldingSetNodeID ID;
  DependentSizedMatrixType::Profile(ID, *this, CanonElementTy, RowExpr,
                                    ColumnExpr);
 
  void *InsertPos = nullptr;
  DependentSizedMatrixType *Canon =
      DependentSizedMatrixTypes.FindNodeOrInsertPos(ID, InsertPos);
 
  if (!Canon) {
    Canon = new (*this, TypeAlignment) DependentSizedMatrixType(
        *this, CanonElementTy, QualType(), RowExpr, ColumnExpr, AttrLoc);
#ifndef NDEBUG
    DependentSizedMatrixType *CanonCheck =
        DependentSizedMatrixTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!CanonCheck && "Dependent-sized matrix canonical type broken");
#endif
    DependentSizedMatrixTypes.InsertNode(Canon, InsertPos);
    Types.push_back(Canon);
  }
 
  // Already have a canonical version of the matrix type
  //
  // If it exactly matches the requested type, use it directly.
  if (Canon->getElementType() == ElementTy && Canon->getRowExpr() == RowExpr &&
      Canon->getRowExpr() == ColumnExpr)
    return QualType(Canon, 0);
 
  // Use Canon as the canonical type for newly-built type.
  DependentSizedMatrixType *New = new (*this, TypeAlignment)
      DependentSizedMatrixType(*this, ElementTy, QualType(Canon, 0), RowExpr,
                               ColumnExpr, AttrLoc);
  Types.push_back(New);
  return QualType(New, 0);
}
 
QualType ASTContext::getDependentAddressSpaceType(QualType PointeeType,
                                                  Expr *AddrSpaceExpr,
                                                  SourceLocation AttrLoc) const {
  assert(AddrSpaceExpr->isInstantiationDependent());
 
  QualType canonPointeeType = getCanonicalType(PointeeType);
 
  void *insertPos = nullptr;
  llvm::FoldingSetNodeID ID;
  DependentAddressSpaceType::Profile(ID, *this, canonPointeeType,
                                     AddrSpaceExpr);
 
  DependentAddressSpaceType *canonTy =
    DependentAddressSpaceTypes.FindNodeOrInsertPos(ID, insertPos);
 
  if (!canonTy) {
    canonTy = new (*this, TypeAlignment)
      DependentAddressSpaceType(*this, canonPointeeType,
                                QualType(), AddrSpaceExpr, AttrLoc);
    DependentAddressSpaceTypes.InsertNode(canonTy, insertPos);
    Types.push_back(canonTy);
  }
 
  if (canonPointeeType == PointeeType &&
      canonTy->getAddrSpaceExpr() == AddrSpaceExpr)
    return QualType(canonTy, 0);
 
  auto *sugaredType
    = new (*this, TypeAlignment)
        DependentAddressSpaceType(*this, PointeeType, QualType(canonTy, 0),
                                  AddrSpaceExpr, AttrLoc);
  Types.push_back(sugaredType);
  return QualType(sugaredType, 0);
}
 
/// Determine whether \p T is canonical as the result type of a function.
static bool isCanonicalResultType(QualType T) {
  return T.isCanonical() &&
         (T.getObjCLifetime() == Qualifiers::OCL_None ||
          T.getObjCLifetime() == Qualifiers::OCL_ExplicitNone);
}
 
/// getFunctionNoProtoType - Return a K&R style C function type like 'int()'.
QualType
ASTContext::getFunctionNoProtoType(QualType ResultTy,
                                   const FunctionType::ExtInfo &Info) const {
  // FIXME: This assertion cannot be enabled (yet) because the ObjC rewriter
  // functionality creates a function without a prototype regardless of
  // language mode (so it makes them even in C++). Once the rewriter has been
  // fixed, this assertion can be enabled again.
  //assert(!LangOpts.requiresStrictPrototypes() &&
  //       "strict prototypes are disabled");
 
  // Unique functions, to guarantee there is only one function of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  FunctionNoProtoType::Profile(ID, ResultTy, Info);
 
  void *InsertPos = nullptr;
  if (FunctionNoProtoType *FT =
        FunctionNoProtoTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(FT, 0);
 
  QualType Canonical;
  if (!isCanonicalResultType(ResultTy)) {
    Canonical =
      getFunctionNoProtoType(getCanonicalFunctionResultType(ResultTy), Info);
 
    // Get the new insert position for the node we care about.
    FunctionNoProtoType *NewIP =
      FunctionNoProtoTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
 
  auto *New = new (*this, TypeAlignment)
    FunctionNoProtoType(ResultTy, Canonical, Info);
  Types.push_back(New);
  FunctionNoProtoTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
CanQualType
ASTContext::getCanonicalFunctionResultType(QualType ResultType) const {
  CanQualType CanResultType = getCanonicalType(ResultType);
 
  // Canonical result types do not have ARC lifetime qualifiers.
  if (CanResultType.getQualifiers().hasObjCLifetime()) {
    Qualifiers Qs = CanResultType.getQualifiers();
    Qs.removeObjCLifetime();
    return CanQualType::CreateUnsafe(
             getQualifiedType(CanResultType.getUnqualifiedType(), Qs));
  }
 
  return CanResultType;
}
 
static bool isCanonicalExceptionSpecification(
    const FunctionProtoType::ExceptionSpecInfo &ESI, bool NoexceptInType) {
  if (ESI.Type == EST_None)
    return true;
  if (!NoexceptInType)
    return false;
 
  // C++17 onwards: exception specification is part of the type, as a simple
  // boolean "can this function type throw".
  if (ESI.Type == EST_BasicNoexcept)
    return true;
 
  // A noexcept(expr) specification is (possibly) canonical if expr is
  // value-dependent.
  if (ESI.Type == EST_DependentNoexcept)
    return true;
 
  // A dynamic exception specification is canonical if it only contains pack
  // expansions (so we can't tell whether it's non-throwing) and all its
  // contained types are canonical.
  if (ESI.Type == EST_Dynamic) {
    bool AnyPackExpansions = false;
    for (QualType ET : ESI.Exceptions) {
      if (!ET.isCanonical())
        return false;
      if (ET->getAs<PackExpansionType>())
        AnyPackExpansions = true;
    }
    return AnyPackExpansions;
  }
 
  return false;
}
 
QualType ASTContext::getFunctionTypeInternal(
    QualType ResultTy, ArrayRef<QualType> ArgArray,
    const FunctionProtoType::ExtProtoInfo &EPI, bool OnlyWantCanonical) const {
  size_t NumArgs = ArgArray.size();
 
  // Unique functions, to guarantee there is only one function of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  FunctionProtoType::Profile(ID, ResultTy, ArgArray.begin(), NumArgs, EPI,
                             *this, true);
 
  QualType Canonical;
  bool Unique = false;
 
  void *InsertPos = nullptr;
  if (FunctionProtoType *FPT =
        FunctionProtoTypes.FindNodeOrInsertPos(ID, InsertPos)) {
    QualType Existing = QualType(FPT, 0);
 
    // If we find a pre-existing equivalent FunctionProtoType, we can just reuse
    // it so long as our exception specification doesn't contain a dependent
    // noexcept expression, or we're just looking for a canonical type.
    // Otherwise, we're going to need to create a type
    // sugar node to hold the concrete expression.
    if (OnlyWantCanonical || !isComputedNoexcept(EPI.ExceptionSpec.Type) ||
        EPI.ExceptionSpec.NoexceptExpr == FPT->getNoexceptExpr())
      return Existing;
 
    // We need a new type sugar node for this one, to hold the new noexcept
    // expression. We do no canonicalization here, but that's OK since we don't
    // expect to see the same noexcept expression much more than once.
    Canonical = getCanonicalType(Existing);
    Unique = true;
  }
 
  bool NoexceptInType = getLangOpts().CPlusPlus17;
  bool IsCanonicalExceptionSpec =
      isCanonicalExceptionSpecification(EPI.ExceptionSpec, NoexceptInType);
 
  // Determine whether the type being created is already canonical or not.
  bool isCanonical = !Unique && IsCanonicalExceptionSpec &&
                     isCanonicalResultType(ResultTy) && !EPI.HasTrailingReturn;
  for (unsigned i = 0; i != NumArgs && isCanonical; ++i)
    if (!ArgArray[i].isCanonicalAsParam())
      isCanonical = false;
 
  if (OnlyWantCanonical)
    assert(isCanonical &&
           "given non-canonical parameters constructing canonical type");
 
  // If this type isn't canonical, get the canonical version of it if we don't
  // already have it. The exception spec is only partially part of the
  // canonical type, and only in C++17 onwards.
  if (!isCanonical && Canonical.isNull()) {
    SmallVector<QualType, 16> CanonicalArgs;
    CanonicalArgs.reserve(NumArgs);
    for (unsigned i = 0; i != NumArgs; ++i)
      CanonicalArgs.push_back(getCanonicalParamType(ArgArray[i]));
 
    llvm::SmallVector<QualType, 8> ExceptionTypeStorage;
    FunctionProtoType::ExtProtoInfo CanonicalEPI = EPI;
    CanonicalEPI.HasTrailingReturn = false;
 
    if (IsCanonicalExceptionSpec) {
      // Exception spec is already OK.
    } else if (NoexceptInType) {
      switch (EPI.ExceptionSpec.Type) {
      case EST_Unparsed: case EST_Unevaluated: case EST_Uninstantiated:
        // We don't know yet. It shouldn't matter what we pick here; no-one
        // should ever look at this.
        [[fallthrough]];
      case EST_None: case EST_MSAny: case EST_NoexceptFalse:
        CanonicalEPI.ExceptionSpec.Type = EST_None;
        break;
 
        // A dynamic exception specification is almost always "not noexcept",
        // with the exception that a pack expansion might expand to no types.
      case EST_Dynamic: {
        bool AnyPacks = false;
        for (QualType ET : EPI.ExceptionSpec.Exceptions) {
          if (ET->getAs<PackExpansionType>())
            AnyPacks = true;
          ExceptionTypeStorage.push_back(getCanonicalType(ET));
        }
        if (!AnyPacks)
          CanonicalEPI.ExceptionSpec.Type = EST_None;
        else {
          CanonicalEPI.ExceptionSpec.Type = EST_Dynamic;
          CanonicalEPI.ExceptionSpec.Exceptions = ExceptionTypeStorage;
        }
        break;
      }
 
      case EST_DynamicNone:
      case EST_BasicNoexcept:
      case EST_NoexceptTrue:
      case EST_NoThrow:
        CanonicalEPI.ExceptionSpec.Type = EST_BasicNoexcept;
        break;
 
      case EST_DependentNoexcept:
        llvm_unreachable("dependent noexcept is already canonical");
      }
    } else {
      CanonicalEPI.ExceptionSpec = FunctionProtoType::ExceptionSpecInfo();
    }
 
    // Adjust the canonical function result type.
    CanQualType CanResultTy = getCanonicalFunctionResultType(ResultTy);
    Canonical =
        getFunctionTypeInternal(CanResultTy, CanonicalArgs, CanonicalEPI, true);
 
    // Get the new insert position for the node we care about.
    FunctionProtoType *NewIP =
      FunctionProtoTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
 
  // Compute the needed size to hold this FunctionProtoType and the
  // various trailing objects.
  auto ESH = FunctionProtoType::getExceptionSpecSize(
      EPI.ExceptionSpec.Type, EPI.ExceptionSpec.Exceptions.size());
  size_t Size = FunctionProtoType::totalSizeToAlloc<
      QualType, SourceLocation, FunctionType::FunctionTypeExtraBitfields,
      FunctionType::ExceptionType, Expr *, FunctionDecl *,
      FunctionProtoType::ExtParameterInfo, Qualifiers>(
      NumArgs, EPI.Variadic, EPI.requiresFunctionProtoTypeExtraBitfields(),
      ESH.NumExceptionType, ESH.NumExprPtr, ESH.NumFunctionDeclPtr,
      EPI.ExtParameterInfos ? NumArgs : 0,
      EPI.TypeQuals.hasNonFastQualifiers() ? 1 : 0);
 
  auto *FTP = (FunctionProtoType *)Allocate(Size, TypeAlignment);
  FunctionProtoType::ExtProtoInfo newEPI = EPI;
  new (FTP) FunctionProtoType(ResultTy, ArgArray, Canonical, newEPI);
  Types.push_back(FTP);
  if (!Unique)
    FunctionProtoTypes.InsertNode(FTP, InsertPos);
  return QualType(FTP, 0);
}
 
QualType ASTContext::getPipeType(QualType T, bool ReadOnly) const {
  llvm::FoldingSetNodeID ID;
  PipeType::Profile(ID, T, ReadOnly);
 
  void *InsertPos = nullptr;
  if (PipeType *PT = PipeTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(PT, 0);
 
  // If the pipe element type isn't canonical, this won't be a canonical type
  // either, so fill in the canonical type field.
  QualType Canonical;
  if (!T.isCanonical()) {
    Canonical = getPipeType(getCanonicalType(T), ReadOnly);
 
    // Get the new insert position for the node we care about.
    PipeType *NewIP = PipeTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!");
    (void)NewIP;
  }
  auto *New = new (*this, TypeAlignment) PipeType(T, Canonical, ReadOnly);
  Types.push_back(New);
  PipeTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
QualType ASTContext::adjustStringLiteralBaseType(QualType Ty) const {
  // OpenCL v1.1 s6.5.3: a string literal is in the constant address space.
  return LangOpts.OpenCL ? getAddrSpaceQualType(Ty, LangAS::opencl_constant)
                         : Ty;
}
 
QualType ASTContext::getReadPipeType(QualType T) const {
  return getPipeType(T, true);
}
 
QualType ASTContext::getWritePipeType(QualType T) const {
  return getPipeType(T, false);
}
 
QualType ASTContext::getBitIntType(bool IsUnsigned, unsigned NumBits) const {
  llvm::FoldingSetNodeID ID;
  BitIntType::Profile(ID, IsUnsigned, NumBits);
 
  void *InsertPos = nullptr;
  if (BitIntType *EIT = BitIntTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(EIT, 0);
 
  auto *New = new (*this, TypeAlignment) BitIntType(IsUnsigned, NumBits);
  BitIntTypes.InsertNode(New, InsertPos);
  Types.push_back(New);
  return QualType(New, 0);
}
 
QualType ASTContext::getDependentBitIntType(bool IsUnsigned,
                                            Expr *NumBitsExpr) const {
  assert(NumBitsExpr->isInstantiationDependent() && "Only good for dependent");
  llvm::FoldingSetNodeID ID;
  DependentBitIntType::Profile(ID, *this, IsUnsigned, NumBitsExpr);
 
  void *InsertPos = nullptr;
  if (DependentBitIntType *Existing =
          DependentBitIntTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(Existing, 0);
 
  auto *New = new (*this, TypeAlignment)
      DependentBitIntType(*this, IsUnsigned, NumBitsExpr);
  DependentBitIntTypes.InsertNode(New, InsertPos);
 
  Types.push_back(New);
  return QualType(New, 0);
}
 
#ifndef NDEBUG
static bool NeedsInjectedClassNameType(const RecordDecl *D) {
  if (!isa<CXXRecordDecl>(D)) return false;
  const auto *RD = cast<CXXRecordDecl>(D);
  if (isa<ClassTemplatePartialSpecializationDecl>(RD))
    return true;
  if (RD->getDescribedClassTemplate() &&
      !isa<ClassTemplateSpecializationDecl>(RD))
    return true;
  return false;
}
#endif
 
/// getInjectedClassNameType - Return the unique reference to the
/// injected class name type for the specified templated declaration.
QualType ASTContext::getInjectedClassNameType(CXXRecordDecl *Decl,
                                              QualType TST) const {
  assert(NeedsInjectedClassNameType(Decl));
  if (Decl->TypeForDecl) {
    assert(isa<InjectedClassNameType>(Decl->TypeForDecl));
  } else if (CXXRecordDecl *PrevDecl = Decl->getPreviousDecl()) {
    assert(PrevDecl->TypeForDecl && "previous declaration has no type");
    Decl->TypeForDecl = PrevDecl->TypeForDecl;
    assert(isa<InjectedClassNameType>(Decl->TypeForDecl));
  } else {
    Type *newType =
      new (*this, TypeAlignment) InjectedClassNameType(Decl, TST);
    Decl->TypeForDecl = newType;
    Types.push_back(newType);
  }
  return QualType(Decl->TypeForDecl, 0);
}
 
/// getTypeDeclType - Return the unique reference to the type for the
/// specified type declaration.
QualType ASTContext::getTypeDeclTypeSlow(const TypeDecl *Decl) const {
  assert(Decl && "Passed null for Decl param");
  assert(!Decl->TypeForDecl && "TypeForDecl present in slow case");
 
  if (const auto *Typedef = dyn_cast<TypedefNameDecl>(Decl))
    return getTypedefType(Typedef);
 
  assert(!isa<TemplateTypeParmDecl>(Decl) &&
         "Template type parameter types are always available.");
 
  if (const auto *Record = dyn_cast<RecordDecl>(Decl)) {
    assert(Record->isFirstDecl() && "struct/union has previous declaration");
    assert(!NeedsInjectedClassNameType(Record));
    return getRecordType(Record);
  } else if (const auto *Enum = dyn_cast<EnumDecl>(Decl)) {
    assert(Enum->isFirstDecl() && "enum has previous declaration");
    return getEnumType(Enum);
  } else if (const auto *Using = dyn_cast<UnresolvedUsingTypenameDecl>(Decl)) {
    return getUnresolvedUsingType(Using);
  } else
    llvm_unreachable("TypeDecl without a type?");
 
  return QualType(Decl->TypeForDecl, 0);
}
 
/// getTypedefType - Return the unique reference to the type for the
/// specified typedef name decl.
QualType ASTContext::getTypedefType(const TypedefNameDecl *Decl,
                                    QualType Underlying) const {
  if (!Decl->TypeForDecl) {
    if (Underlying.isNull())
      Underlying = Decl->getUnderlyingType();
    auto *NewType = new (*this, TypeAlignment) TypedefType(
        Type::Typedef, Decl, QualType(), getCanonicalType(Underlying));
    Decl->TypeForDecl = NewType;
    Types.push_back(NewType);
    return QualType(NewType, 0);
  }
  if (Underlying.isNull() || Decl->getUnderlyingType() == Underlying)
    return QualType(Decl->TypeForDecl, 0);
  assert(hasSameType(Decl->getUnderlyingType(), Underlying));
 
  llvm::FoldingSetNodeID ID;
  TypedefType::Profile(ID, Decl, Underlying);
 
  void *InsertPos = nullptr;
  if (TypedefType *T = TypedefTypes.FindNodeOrInsertPos(ID, InsertPos)) {
    assert(!T->typeMatchesDecl() &&
           "non-divergent case should be handled with TypeDecl");
    return QualType(T, 0);
  }
 
  void *Mem =
      Allocate(TypedefType::totalSizeToAlloc<QualType>(true), TypeAlignment);
  auto *NewType = new (Mem) TypedefType(Type::Typedef, Decl, Underlying,
                                        getCanonicalType(Underlying));
  TypedefTypes.InsertNode(NewType, InsertPos);
  Types.push_back(NewType);
  return QualType(NewType, 0);
}
 
QualType ASTContext::getUsingType(const UsingShadowDecl *Found,
                                  QualType Underlying) const {
  llvm::FoldingSetNodeID ID;
  UsingType::Profile(ID, Found, Underlying);
 
  void *InsertPos = nullptr;
  if (UsingType *T = UsingTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(T, 0);
 
  const Type *TypeForDecl =
      cast<TypeDecl>(Found->getTargetDecl())->getTypeForDecl();
 
  assert(!Underlying.hasLocalQualifiers());
  QualType Canon = Underlying->getCanonicalTypeInternal();
  assert(TypeForDecl->getCanonicalTypeInternal() == Canon);
 
  if (Underlying.getTypePtr() == TypeForDecl)
    Underlying = QualType();
  void *Mem =
      Allocate(UsingType::totalSizeToAlloc<QualType>(!Underlying.isNull()),
               TypeAlignment);
  UsingType *NewType = new (Mem) UsingType(Found, Underlying, Canon);
  Types.push_back(NewType);
  UsingTypes.InsertNode(NewType, InsertPos);
  return QualType(NewType, 0);
}
 
QualType ASTContext::getRecordType(const RecordDecl *Decl) const {
  if (Decl->TypeForDecl) return QualType(Decl->TypeForDecl, 0);
 
  if (const RecordDecl *PrevDecl = Decl->getPreviousDecl())
    if (PrevDecl->TypeForDecl)
      return QualType(Decl->TypeForDecl = PrevDecl->TypeForDecl, 0);
 
  auto *newType = new (*this, TypeAlignment) RecordType(Decl);
  Decl->TypeForDecl = newType;
  Types.push_back(newType);
  return QualType(newType, 0);
}
 
QualType ASTContext::getEnumType(const EnumDecl *Decl) const {
  if (Decl->TypeForDecl) return QualType(Decl->TypeForDecl, 0);
 
  if (const EnumDecl *PrevDecl = Decl->getPreviousDecl())
    if (PrevDecl->TypeForDecl)
      return QualType(Decl->TypeForDecl = PrevDecl->TypeForDecl, 0);
 
  auto *newType = new (*this, TypeAlignment) EnumType(Decl);
  Decl->TypeForDecl = newType;
  Types.push_back(newType);
  return QualType(newType, 0);
}
 
QualType ASTContext::getUnresolvedUsingType(
    const UnresolvedUsingTypenameDecl *Decl) const {
  if (Decl->TypeForDecl)
    return QualType(Decl->TypeForDecl, 0);
 
  if (const UnresolvedUsingTypenameDecl *CanonicalDecl =
          Decl->getCanonicalDecl())
    if (CanonicalDecl->TypeForDecl)
      return QualType(Decl->TypeForDecl = CanonicalDecl->TypeForDecl, 0);
 
  Type *newType = new (*this, TypeAlignment) UnresolvedUsingType(Decl);
  Decl->TypeForDecl = newType;
  Types.push_back(newType);
  return QualType(newType, 0);
}
 
QualType ASTContext::getAttributedType(attr::Kind attrKind,
                                       QualType modifiedType,
                                       QualType equivalentType) const {
  llvm::FoldingSetNodeID id;
  AttributedType::Profile(id, attrKind, modifiedType, equivalentType);
 
  void *insertPos = nullptr;
  AttributedType *type = AttributedTypes.FindNodeOrInsertPos(id, insertPos);
  if (type) return QualType(type, 0);
 
  QualType canon = getCanonicalType(equivalentType);
  type = new (*this, TypeAlignment)
      AttributedType(canon, attrKind, modifiedType, equivalentType);
 
  Types.push_back(type);
  AttributedTypes.InsertNode(type, insertPos);
 
  return QualType(type, 0);
}
 
QualType ASTContext::getBTFTagAttributedType(const BTFTypeTagAttr *BTFAttr,
                                             QualType Wrapped) {
  llvm::FoldingSetNodeID ID;
  BTFTagAttributedType::Profile(ID, Wrapped, BTFAttr);
 
  void *InsertPos = nullptr;
  BTFTagAttributedType *Ty =
      BTFTagAttributedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (Ty)
    return QualType(Ty, 0);
 
  QualType Canon = getCanonicalType(Wrapped);
  Ty = new (*this, TypeAlignment) BTFTagAttributedType(Canon, Wrapped, BTFAttr);
 
  Types.push_back(Ty);
  BTFTagAttributedTypes.InsertNode(Ty, InsertPos);
 
  return QualType(Ty, 0);
}
 
/// Retrieve a substitution-result type.
QualType ASTContext::getSubstTemplateTypeParmType(
    QualType Replacement, Decl *AssociatedDecl, unsigned Index,
    std::optional<unsigned> PackIndex) const {
  llvm::FoldingSetNodeID ID;
  SubstTemplateTypeParmType::Profile(ID, Replacement, AssociatedDecl, Index,
                                     PackIndex);
  void *InsertPos = nullptr;
  SubstTemplateTypeParmType *SubstParm =
      SubstTemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);
 
  if (!SubstParm) {
    void *Mem = Allocate(SubstTemplateTypeParmType::totalSizeToAlloc<QualType>(
                             !Replacement.isCanonical()),
                         TypeAlignment);
    SubstParm = new (Mem) SubstTemplateTypeParmType(Replacement, AssociatedDecl,
                                                    Index, PackIndex);
    Types.push_back(SubstParm);
    SubstTemplateTypeParmTypes.InsertNode(SubstParm, InsertPos);
  }
 
  return QualType(SubstParm, 0);
}
 
/// Retrieve a
QualType
ASTContext::getSubstTemplateTypeParmPackType(Decl *AssociatedDecl,
                                             unsigned Index, bool Final,
                                             const TemplateArgument &ArgPack) {
#ifndef NDEBUG
  for (const auto &P : ArgPack.pack_elements())
    assert(P.getKind() == TemplateArgument::Type && "Pack contains a non-type");
#endif
 
  llvm::FoldingSetNodeID ID;
  SubstTemplateTypeParmPackType::Profile(ID, AssociatedDecl, Index, Final,
                                         ArgPack);
  void *InsertPos = nullptr;
  if (SubstTemplateTypeParmPackType *SubstParm =
          SubstTemplateTypeParmPackTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(SubstParm, 0);
 
  QualType Canon;
  {
    TemplateArgument CanonArgPack = getCanonicalTemplateArgument(ArgPack);
    if (!AssociatedDecl->isCanonicalDecl() ||
        !CanonArgPack.structurallyEquals(ArgPack)) {
      Canon = getSubstTemplateTypeParmPackType(
          AssociatedDecl->getCanonicalDecl(), Index, Final, CanonArgPack);
      [[maybe_unused]] const auto *Nothing =
          SubstTemplateTypeParmPackTypes.FindNodeOrInsertPos(ID, InsertPos);
      assert(!Nothing);
    }
  }
 
  auto *SubstParm = new (*this, TypeAlignment) SubstTemplateTypeParmPackType(
      Canon, AssociatedDecl, Index, Final, ArgPack);
  Types.push_back(SubstParm);
  SubstTemplateTypeParmPackTypes.InsertNode(SubstParm, InsertPos);
  return QualType(SubstParm, 0);
}
 
/// Retrieve the template type parameter type for a template
/// parameter or parameter pack with the given depth, index, and (optionally)
/// name.
QualType ASTContext::getTemplateTypeParmType(unsigned Depth, unsigned Index,
                                             bool ParameterPack,
                                             TemplateTypeParmDecl *TTPDecl) const {
  llvm::FoldingSetNodeID ID;
  TemplateTypeParmType::Profile(ID, Depth, Index, ParameterPack, TTPDecl);
  void *InsertPos = nullptr;
  TemplateTypeParmType *TypeParm
    = TemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);
 
  if (TypeParm)
    return QualType(TypeParm, 0);
 
  if (TTPDecl) {
    QualType Canon = getTemplateTypeParmType(Depth, Index, ParameterPack);
    TypeParm = new (*this, TypeAlignment) TemplateTypeParmType(TTPDecl, Canon);
 
    TemplateTypeParmType *TypeCheck
      = TemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!TypeCheck && "Template type parameter canonical type broken");
    (void)TypeCheck;
  } else
    TypeParm = new (*this, TypeAlignment)
      TemplateTypeParmType(Depth, Index, ParameterPack);
 
  Types.push_back(TypeParm);
  TemplateTypeParmTypes.InsertNode(TypeParm, InsertPos);
 
  return QualType(TypeParm, 0);
}
 
TypeSourceInfo *
ASTContext::getTemplateSpecializationTypeInfo(TemplateName Name,
                                              SourceLocation NameLoc,
                                        const TemplateArgumentListInfo &Args,
                                              QualType Underlying) const {
  assert(!Name.getAsDependentTemplateName() &&
         "No dependent template names here!");
  QualType TST =
      getTemplateSpecializationType(Name, Args.arguments(), Underlying);
 
  TypeSourceInfo *DI = CreateTypeSourceInfo(TST);
  TemplateSpecializationTypeLoc TL =
      DI->getTypeLoc().castAs<TemplateSpecializationTypeLoc>();
  TL.setTemplateKeywordLoc(SourceLocation());
  TL.setTemplateNameLoc(NameLoc);
  TL.setLAngleLoc(Args.getLAngleLoc());
  TL.setRAngleLoc(Args.getRAngleLoc());
  for (unsigned i = 0, e = TL.getNumArgs(); i != e; ++i)
    TL.setArgLocInfo(i, Args[i].getLocInfo());
  return DI;
}
 
QualType
ASTContext::getTemplateSpecializationType(TemplateName Template,
                                          ArrayRef<TemplateArgumentLoc> Args,
                                          QualType Underlying) const {
  assert(!Template.getAsDependentTemplateName() &&
         "No dependent template names here!");
 
  SmallVector<TemplateArgument, 4> ArgVec;
  ArgVec.reserve(Args.size());
  for (const TemplateArgumentLoc &Arg : Args)
    ArgVec.push_back(Arg.getArgument());
 
  return getTemplateSpecializationType(Template, ArgVec, Underlying);
}
 
#ifndef NDEBUG
static bool hasAnyPackExpansions(ArrayRef<TemplateArgument> Args) {
  for (const TemplateArgument &Arg : Args)
    if (Arg.isPackExpansion())
      return true;
 
  return true;
}
#endif
 
QualType
ASTContext::getTemplateSpecializationType(TemplateName Template,
                                          ArrayRef<TemplateArgument> Args,
                                          QualType Underlying) const {
  assert(!Template.getAsDependentTemplateName() &&
         "No dependent template names here!");
  // Look through qualified template names.
  if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
    Template = QTN->getUnderlyingTemplate();
 
  const auto *TD = Template.getAsTemplateDecl();
  bool IsTypeAlias = TD && TD->isTypeAlias();
  QualType CanonType;
  if (!Underlying.isNull())
    CanonType = getCanonicalType(Underlying);
  else {
    // We can get here with an alias template when the specialization contains
    // a pack expansion that does not match up with a parameter pack.
    assert((!IsTypeAlias || hasAnyPackExpansions(Args)) &&
           "Caller must compute aliased type");
    IsTypeAlias = false;
    CanonType = getCanonicalTemplateSpecializationType(Template, Args);
  }
 
  // Allocate the (non-canonical) template specialization type, but don't
  // try to unique it: these types typically have location information that
  // we don't unique and don't want to lose.
  void *Mem = Allocate(sizeof(TemplateSpecializationType) +
                       sizeof(TemplateArgument) * Args.size() +
                       (IsTypeAlias? sizeof(QualType) : 0),
                       TypeAlignment);
  auto *Spec
    = new (Mem) TemplateSpecializationType(Template, Args, CanonType,
                                         IsTypeAlias ? Underlying : QualType());
 
  Types.push_back(Spec);
  return QualType(Spec, 0);
}
 
QualType ASTContext::getCanonicalTemplateSpecializationType(
    TemplateName Template, ArrayRef<TemplateArgument> Args) const {
  assert(!Template.getAsDependentTemplateName() &&
         "No dependent template names here!");
 
  // Look through qualified template names.
  if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
    Template = TemplateName(QTN->getUnderlyingTemplate());
 
  // Build the canonical template specialization type.
  TemplateName CanonTemplate = getCanonicalTemplateName(Template);
  bool AnyNonCanonArgs = false;
  auto CanonArgs =
      ::getCanonicalTemplateArguments(*this, Args, AnyNonCanonArgs);
 
  // Determine whether this canonical template specialization type already
  // exists.
  llvm::FoldingSetNodeID ID;
  TemplateSpecializationType::Profile(ID, CanonTemplate,
                                      CanonArgs, *this);
 
  void *InsertPos = nullptr;
  TemplateSpecializationType *Spec
    = TemplateSpecializationTypes.FindNodeOrInsertPos(ID, InsertPos);
 
  if (!Spec) {
    // Allocate a new canonical template specialization type.
    void *Mem = Allocate((sizeof(TemplateSpecializationType) +
                          sizeof(TemplateArgument) * CanonArgs.size()),
                         TypeAlignment);
    Spec = new (Mem) TemplateSpecializationType(CanonTemplate,
                                                CanonArgs,
                                                QualType(), QualType());
    Types.push_back(Spec);
    TemplateSpecializationTypes.InsertNode(Spec, InsertPos);
  }
 
  assert(Spec->isDependentType() &&
         "Non-dependent template-id type must have a canonical type");
  return QualType(Spec, 0);
}
 
QualType ASTContext::getElaboratedType(ElaboratedTypeKeyword Keyword,
                                       NestedNameSpecifier *NNS,
                                       QualType NamedType,
                                       TagDecl *OwnedTagDecl) const {
  llvm::FoldingSetNodeID ID;
  ElaboratedType::Profile(ID, Keyword, NNS, NamedType, OwnedTagDecl);
 
  void *InsertPos = nullptr;
  ElaboratedType *T = ElaboratedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);
 
  QualType Canon = NamedType;
  if (!Canon.isCanonical()) {
    Canon = getCanonicalType(NamedType);
    ElaboratedType *CheckT = ElaboratedTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!CheckT && "Elaborated canonical type broken");
    (void)CheckT;
  }
 
  void *Mem = Allocate(ElaboratedType::totalSizeToAlloc<TagDecl *>(!!OwnedTagDecl),
                       TypeAlignment);
  T = new (Mem) ElaboratedType(Keyword, NNS, NamedType, Canon, OwnedTagDecl);
 
  Types.push_back(T);
  ElaboratedTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}
 
QualType
ASTContext::getParenType(QualType InnerType) const {
  llvm::FoldingSetNodeID ID;
  ParenType::Profile(ID, InnerType);
 
  void *InsertPos = nullptr;
  ParenType *T = ParenTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);
 
  QualType Canon = InnerType;
  if (!Canon.isCanonical()) {
    Canon = getCanonicalType(InnerType);
    ParenType *CheckT = ParenTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!CheckT && "Paren canonical type broken");
    (void)CheckT;
  }
 
  T = new (*this, TypeAlignment) ParenType(InnerType, Canon);
  Types.push_back(T);
  ParenTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}
 
QualType
ASTContext::getMacroQualifiedType(QualType UnderlyingTy,
                                  const IdentifierInfo *MacroII) const {
  QualType Canon = UnderlyingTy;
  if (!Canon.isCanonical())
    Canon = getCanonicalType(UnderlyingTy);
 
  auto *newType = new (*this, TypeAlignment)
      MacroQualifiedType(UnderlyingTy, Canon, MacroII);
  Types.push_back(newType);
  return QualType(newType, 0);
}
 
QualType ASTContext::getDependentNameType(ElaboratedTypeKeyword Keyword,
                                          NestedNameSpecifier *NNS,
                                          const IdentifierInfo *Name,
                                          QualType Canon) const {
  if (Canon.isNull()) {
    NestedNameSpecifier *CanonNNS = getCanonicalNestedNameSpecifier(NNS);
    if (CanonNNS != NNS)
      Canon = getDependentNameType(Keyword, CanonNNS, Name);
  }
 
  llvm::FoldingSetNodeID ID;
  DependentNameType::Profile(ID, Keyword, NNS, Name);
 
  void *InsertPos = nullptr;
  DependentNameType *T
    = DependentNameTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);
 
  T = new (*this, TypeAlignment) DependentNameType(Keyword, NNS, Name, Canon);
  Types.push_back(T);
  DependentNameTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}
 
QualType ASTContext::getDependentTemplateSpecializationType(
    ElaboratedTypeKeyword Keyword, NestedNameSpecifier *NNS,
    const IdentifierInfo *Name, ArrayRef<TemplateArgumentLoc> Args) const {
  // TODO: avoid this copy
  SmallVector<TemplateArgument, 16> ArgCopy;
  for (unsigned I = 0, E = Args.size(); I != E; ++I)
    ArgCopy.push_back(Args[I].