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 "ByteCode/Context.h"
#include "CXXABI.h"
#include "clang/AST/APValue.h"
#include "clang/AST/ASTConcept.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/ASTStructuralEquivalence.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/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/ProfileList.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/SipHash.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TargetParser/AArch64TargetParser.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 The locations that are relevant when searching for Doc comments
/// related to \p D.
static SmallVector<SourceLocation, 2>
getDeclLocsForCommentSearch(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 {};
 
  SmallVector<SourceLocation, 2> Locations;
  // 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".
  SourceLocation BaseLocation;
  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))
    BaseLocation = D->getBeginLoc();
  else
    BaseLocation = D->getLocation();
 
  if (!D->getLocation().isMacroID()) {
    Locations.emplace_back(BaseLocation);
  } else {
    const auto *DeclCtx = D->getDeclContext();
 
    // When encountering definitions generated from a macro (that are not
    // contained by another declaration in the macro) we need to try and find
    // the comment at the location of the expansion but if there is no comment
    // there we should retry to see if there is a comment inside the macro as
    // well. To this end we return first BaseLocation to first look at the
    // expansion site, the second value is the spelling location of the
    // beginning of the declaration defined inside the macro.
    if (!(DeclCtx &&
          Decl::castFromDeclContext(DeclCtx)->getLocation().isMacroID())) {
      Locations.emplace_back(SourceMgr.getExpansionLoc(BaseLocation));
    }
 
    // We use Decl::getBeginLoc() and not just BaseLocation here to ensure that
    // we don't refer to the macro argument location at the expansion site (this
    // can happen if the name's spelling is provided via macro argument), and
    // always to the declaration itself.
    Locations.emplace_back(SourceMgr.getSpellingLoc(D->getBeginLoc()));
  }
 
  return Locations;
}
 
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 FileIDAndOffset 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 auto DeclLocs = getDeclLocsForCommentSearch(D, SourceMgr);
 
  for (const auto DeclLoc : DeclLocs) {
    // If the declaration doesn't map directly to a location in a file, we
    // can't find the comment.
    if (DeclLoc.isInvalid() || !DeclLoc.isFileID())
      continue;
 
    if (ExternalSource && !CommentsLoaded) {
      ExternalSource->ReadComments();
      CommentsLoaded = true;
    }
 
    if (Comments.empty())
      continue;
 
    const FileID File = SourceMgr.getDecomposedLoc(DeclLoc).first;
    if (!File.isValid())
      continue;
 
    const auto CommentsInThisFile = Comments.getCommentsInFile(File);
    if (!CommentsInThisFile || CommentsInThisFile->empty())
      continue;
 
    if (RawComment *Comment =
            getRawCommentForDeclNoCacheImpl(D, DeclLoc, *CommentsInThisFile))
      return Comment;
  }
 
  return nullptr;
}
 
void ASTContext::addComment(const RawComment &RC) {
  assert(LangOpts.RetainCommentsFromSystemHeaders ||
         !SourceMgr.isInSystemHeader(RC.getSourceRange().getBegin()));
  Comments.addComment(RC, LangOpts.CommentOpts, BumpAlloc);
}
 
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?
  const Decl *LastCheckedRedecl = [&]() {
    const Decl *LastChecked = CommentlessRedeclChains.lookup(CanonicalD);
    bool CanUseCommentlessCache = false;
    if (LastChecked) {
      for (auto *Redecl : CanonicalD->redecls()) {
        if (Redecl == D) {
          CanUseCommentlessCache = true;
          break;
        }
        if (Redecl == LastChecked)
          break;
      }
    }
    // FIXME: This could be improved so that even if CanUseCommentlessCache
    // is false, once we've traversed past CanonicalD we still skip ahead
    // LastChecked.
    return CanUseCommentlessCache ? LastChecked : nullptr;
  }();
 
  for (const Decl *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 (const Decl *D : Decls) {
    if (D->isInvalidDecl())
      continue;
 
    D = &adjustDeclToTemplate(*D);
    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);
 
    if (DeclRawComments.count(D) > 0)
      continue;
 
    const auto DeclLocs = getDeclLocsForCommentSearch(D, SourceMgr);
 
    for (const auto DeclLoc : DeclLocs) {
      if (DeclLoc.isInvalid() || !DeclLoc.isFileID())
        continue;
 
      if (RawComment *const DocComment = getRawCommentForDeclNoCacheImpl(
              D, DeclLoc, *CommentsInThisFile)) {
        cacheRawCommentForDecl(*D, *DocComment);
        comments::FullComment *FC = DocComment->parse(*this, PP, D);
        ParsedComments[D->getCanonicalDecl()] = FC;
        break;
      }
    }
  }
}
 
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 (comments::FullComment *FC = getCommentForDecl(TT->getDecl(), 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());
  ID.AddInteger(Parm->templateParameterKind());
 
  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());
      ID.AddInteger(
          TTP->getNumExpansionParameters().toInternalRepresentation());
      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->getNumExpansionParameters());
      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,
      TTP->templateParameterKind(),
      /*Typename=*/false,
      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;
}
 
TemplateTemplateParmDecl *
ASTContext::findCanonicalTemplateTemplateParmDeclInternal(
    TemplateTemplateParmDecl *TTP) const {
  llvm::FoldingSetNodeID ID;
  CanonicalTemplateTemplateParm::Profile(ID, *this, TTP);
  void *InsertPos = nullptr;
  CanonicalTemplateTemplateParm *Canonical =
      CanonTemplateTemplateParms.FindNodeOrInsertPos(ID, InsertPos);
  return Canonical ? Canonical->getParam() : nullptr;
}
 
TemplateTemplateParmDecl *
ASTContext::insertCanonicalTemplateTemplateParmDeclInternal(
    TemplateTemplateParmDecl *CanonTTP) const {
  llvm::FoldingSetNodeID ID;
  CanonicalTemplateTemplateParm::Profile(ID, *this, CanonTTP);
  void *InsertPos = nullptr;
  if (auto *Existing =
          CanonTemplateTemplateParms.FindNodeOrInsertPos(ID, InsertPos))
    return Existing->getParam();
  CanonTemplateTemplateParms.InsertNode(
      new (*this) CanonicalTemplateTemplateParm(CanonTTP), InsertPos);
  return CanonTTP;
}
 
/// Check if a type can have its sanitizer instrumentation elided based on its
/// presence within an ignorelist.
bool ASTContext::isTypeIgnoredBySanitizer(const SanitizerMask &Mask,
                                          const QualType &Ty) const {
  std::string TyName = Ty.getUnqualifiedType().getAsString(getPrintingPolicy());
  return NoSanitizeL->containsType(Mask, TyName);
}
 
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;
}
 
ParentMapContext &ASTContext::getParentMapContext() {
  if (!ParentMapCtx)
    ParentMapCtx.reset(new ParentMapContext(*this));
  return *ParentMapCtx;
}
 
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),
      DependentSizedArrayTypes(this_()), DependentSizedExtVectorTypes(this_()),
      DependentAddressSpaceTypes(this_()), DependentVectorTypes(this_()),
      DependentSizedMatrixTypes(this_()),
      FunctionProtoTypes(this_(), FunctionProtoTypesLog2InitSize),
      DependentTypeOfExprTypes(this_()), DependentDecltypeTypes(this_()),
      DependentPackIndexingTypes(this_()), TemplateSpecializationTypes(this_()),
      DependentBitIntTypes(this_()), SubstTemplateTemplateParmPacks(this_()),
      DeducedTemplates(this_()), ArrayParameterTypes(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 ObjCInterfaceDecl *,
                      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();
 
  XRayFilter.reset();
  NoSanitizeL.reset();
}
 
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 && !ND->isUnconditionallyVisible())
      Listener->RedefinedHiddenDefinition(ND, M);
 
  MergedDefModules[cast<NamedDecl>(ND->getCanonicalDecl())].push_back(M);
}
 
void ASTContext::deduplicateMergedDefinitionsFor(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(Merged, nullptr);
}
 
ArrayRef<Module *>
ASTContext::getModulesWithMergedDefinition(const NamedDecl *Def) {
  auto MergedIt =
      MergedDefModules.find(cast<NamedDecl>(Def->getCanonicalDecl()));
  if (MergedIt == MergedDefModules.end())
    return {};
  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<GlobalDeclID> 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 {};
 
  auto *Inits = It->second;
  Inits->resolve(*this);
  return Inits->Initializers;
}
 
void ASTContext::setCurrentNamedModule(Module *M) {
  assert(M->isNamedModule());
  assert(!CurrentCXXNamedModule &&
         "We should set named module for ASTContext for only once");
  CurrentCXXNamedModule = M;
}
 
bool ASTContext::isInSameModule(const Module *M1, const Module *M2) const {
  if (!M1 != !M2)
    return false;
 
  /// Get the representative module for M. The representative module is the
  /// first module unit for a specific primary module name. So that the module
  /// units have the same representative module belongs to the same module.
  ///
  /// The process is helpful to reduce the expensive string operations.
  auto GetRepresentativeModule = [this](const Module *M) {
    auto Iter = SameModuleLookupSet.find(M);
    if (Iter != SameModuleLookupSet.end())
      return Iter->second;
 
    const Module *RepresentativeModule =
        PrimaryModuleNameMap.try_emplace(M->getPrimaryModuleInterfaceName(), M)
            .first->second;
    SameModuleLookupSet[M] = RepresentativeModule;
    return RepresentativeModule;
  };
 
  assert(M1 && "Shouldn't call `isInSameModule` if both M1 and M2 are none.");
  return GetRepresentativeModule(M1) == GetRepresentativeModule(M2);
}
 
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;
}
 
#define BuiltinTemplate(BTName)                                                \
  BuiltinTemplateDecl *ASTContext::get##BTName##Decl() const {                 \
    if (!Decl##BTName)                                                         \
      Decl##BTName =                                                           \
          buildBuiltinTemplateDecl(BTK##BTName, get##BTName##Name());          \
    return Decl##BTName;                                                       \
  }
#include "clang/Basic/BuiltinTemplates.inc"
 
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, alignof(BuiltinType)) 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 unresolved templates.
  InitBuiltinType(UnresolvedTemplateTy, BuiltinType::UnresolvedTemplate);
 
  // 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(ArraySectionTy, BuiltinType::ArraySection);
    InitBuiltinType(OMPArrayShapingTy, BuiltinType::OMPArrayShaping);
    InitBuiltinType(OMPIteratorTy, BuiltinType::OMPIterator);
  }
  // Placeholder type for OpenACC array sections, if we are ALSO in OMP mode,
  // don't bother, as we're just using the same type as OMP.
  if (LangOpts.OpenACC && !LangOpts.OpenMP) {
    InitBuiltinType(ArraySectionTy, BuiltinType::ArraySection);
  }
  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 (LangOpts.HLSL) {
#define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId)                            \
  InitBuiltinType(SingletonId, BuiltinType::Id);
#include "clang/Basic/HLSLIntangibleTypes.def"
  }
 
  if (Target.hasAArch64ACLETypes() ||
      (AuxTarget && AuxTarget->hasAArch64ACLETypes())) {
#define SVE_TYPE(Name, Id, SingletonId)                                        \
  InitBuiltinType(SingletonId, BuiltinType::Id);
#include "clang/Basic/AArch64ACLETypes.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"
  }
 
  if (Target.getTriple().isAMDGPU() ||
      (AuxTarget && AuxTarget->getTriple().isAMDGPU())) {
#define AMDGPU_TYPE(Name, Id, SingletonId, Width, Align)                       \
  InitBuiltinType(SingletonId, BuiltinType::Id);
#include "clang/Basic/AMDGPUTypes.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) {
  return InstantiatedFromUsingDecl.lookup(UUD);
}
 
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) {
  return InstantiatedFromUsingEnumDecl.lookup(UUD);
}
 
void ASTContext::setInstantiatedFromUsingEnumDecl(UsingEnumDecl *Inst,
                                                  UsingEnumDecl *Pattern) {
  assert(!InstantiatedFromUsingEnumDecl[Inst] && "pattern already exists");
  InstantiatedFromUsingEnumDecl[Inst] = Pattern;
}
 
UsingShadowDecl *
ASTContext::getInstantiatedFromUsingShadowDecl(UsingShadowDecl *Inst) {
  return InstantiatedFromUsingShadowDecl.lookup(Inst);
}
 
void
ASTContext::setInstantiatedFromUsingShadowDecl(UsingShadowDecl *Inst,
                                               UsingShadowDecl *Pattern) {
  assert(!InstantiatedFromUsingShadowDecl[Inst] && "pattern already exists");
  InstantiatedFromUsingShadowDecl[Inst] = Pattern;
}
 
FieldDecl *
ASTContext::getInstantiatedFromUnnamedFieldDecl(FieldDecl *Field) const {
  return InstantiatedFromUnnamedFieldDecl.lookup(Field);
}
 
void ASTContext::setInstantiatedFromUnnamedFieldDecl(FieldDecl *Inst,
                                                     FieldDecl *Tmpl) {
  assert((!Inst->getDeclName() || Inst->isPlaceholderVar(getLangOpts())) &&
         "Instantiated field decl is not unnamed");
  assert((!Inst->getDeclName() || Inst->isPlaceholderVar(getLangOpts())) &&
         "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());
}
 
std::optional<ASTContext::CXXRecordDeclRelocationInfo>
ASTContext::getRelocationInfoForCXXRecord(const CXXRecordDecl *RD) const {
  assert(RD);
  CXXRecordDecl *D = RD->getDefinition();
  auto it = RelocatableClasses.find(D);
  if (it != RelocatableClasses.end())
    return it->getSecond();
  return std::nullopt;
}
 
void ASTContext::setRelocationInfoForCXXRecord(
    const CXXRecordDecl *RD, CXXRecordDeclRelocationInfo Info) {
  assert(RD);
  CXXRecordDecl *D = RD->getDefinition();
  assert(RelocatableClasses.find(D) == RelocatableClasses.end());
  RelocatableClasses.insert({D, Info});
}
 
static bool primaryBaseHaseAddressDiscriminatedVTableAuthentication(
    const ASTContext &Context, const CXXRecordDecl *Class) {
  if (!Class->isPolymorphic())
    return false;
  const CXXRecordDecl *BaseType = Context.baseForVTableAuthentication(Class);
  using AuthAttr = VTablePointerAuthenticationAttr;
  const AuthAttr *ExplicitAuth = BaseType->getAttr<AuthAttr>();
  if (!ExplicitAuth)
    return Context.getLangOpts().PointerAuthVTPtrAddressDiscrimination;
  AuthAttr::AddressDiscriminationMode AddressDiscrimination =
      ExplicitAuth->getAddressDiscrimination();
  if (AddressDiscrimination == AuthAttr::DefaultAddressDiscrimination)
    return Context.getLangOpts().PointerAuthVTPtrAddressDiscrimination;
  return AddressDiscrimination == AuthAttr::AddressDiscrimination;
}
 
ASTContext::PointerAuthContent
ASTContext::findPointerAuthContent(QualType T) const {
  assert(isPointerAuthenticationAvailable());
 
  T = T.getCanonicalType();
  if (T->isDependentType())
    return PointerAuthContent::None;
 
  if (T.hasAddressDiscriminatedPointerAuth())
    return PointerAuthContent::AddressDiscriminatedData;
  const RecordDecl *RD = T->getAsRecordDecl();
  if (!RD)
    return PointerAuthContent::None;
 
  if (RD->isInvalidDecl())
    return PointerAuthContent::None;
 
  if (auto Existing = RecordContainsAddressDiscriminatedPointerAuth.find(RD);
      Existing != RecordContainsAddressDiscriminatedPointerAuth.end())
    return Existing->second;
 
  PointerAuthContent Result = PointerAuthContent::None;
 
  auto SaveResultAndReturn = [&]() -> PointerAuthContent {
    auto [ResultIter, DidAdd] =
        RecordContainsAddressDiscriminatedPointerAuth.try_emplace(RD, Result);
    (void)ResultIter;
    (void)DidAdd;
    assert(DidAdd);
    return Result;
  };
  auto ShouldContinueAfterUpdate = [&](PointerAuthContent NewResult) {
    static_assert(PointerAuthContent::None <
                  PointerAuthContent::AddressDiscriminatedVTable);
    static_assert(PointerAuthContent::AddressDiscriminatedVTable <
                  PointerAuthContent::AddressDiscriminatedData);
    if (NewResult > Result)
      Result = NewResult;
    return Result != PointerAuthContent::AddressDiscriminatedData;
  };
  if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
    if (primaryBaseHaseAddressDiscriminatedVTableAuthentication(*this, CXXRD) &&
        !ShouldContinueAfterUpdate(
            PointerAuthContent::AddressDiscriminatedVTable))
      return SaveResultAndReturn();
    for (auto Base : CXXRD->bases()) {
      if (!ShouldContinueAfterUpdate(findPointerAuthContent(Base.getType())))
        return SaveResultAndReturn();
    }
  }
  for (auto *FieldDecl : RD->fields()) {
    if (!ShouldContinueAfterUpdate(
            findPointerAuthContent(FieldDecl->getType())))
      return SaveResultAndReturn();
  }
  return SaveResultAndReturn();
}
 
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:
    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().OpenMPIsTargetDevice)
      return AuxTarget->getLongDoubleFormat();
    return Target->getLongDoubleFormat();
  case BuiltinType::Float128:
    if (getLangOpts().OpenMP && getLangOpts().OpenMPIsTargetDevice)
      return AuxTarget->getFloat128Format();
    return Target->getFloat128Format();
  }
}
 
CharUnits ASTContext::getDeclAlign(const Decl *D, bool ForAlignof) const {
  unsigned Align = Target->getCharWidth();
 
  const unsigned AlignFromAttr = D->getMaxAlignment();
  if (AlignFromAttr)
    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.
  bool UseAlignAttrOnly;
  if (const FieldDecl *FD = dyn_cast<FieldDecl>(D))
    UseAlignAttrOnly =
        FD->hasAttr<PackedAttr>() || FD->getParent()->hasAttr<PackedAttr>();
  else
    UseAlignAttrOnly = AlignFromAttr != 0;
  // 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();
    }
 
    // Ensure minimum alignment for global variables.
    if (const auto *VD = dyn_cast<VarDecl>(D))
      if (VD->hasGlobalStorage() && !ForAlignof) {
        uint64_t TypeSize =
            !BaseT->isIncompleteType() ? getTypeSize(T.getTypePtr()) : 0;
        Align = std::max(Align, getMinGlobalAlignOfVar(TypeSize, VD));
      }
 
    // 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 *RD = T->getAsCXXRecordDecl(); RD && !RD->isInvalidDecl()) {
      const ASTRecordLayout &layout = getASTRecordLayout(RD);
      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->getZExtSize();
  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 *ED = T->getAsEnumDecl()) {
    if (T->isDependentType() || ED->getPromotionType().isNull() ||
        ED->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 *TD = T->getAsTagDecl())
    return TD->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:
  case Type::ArrayParameter: {
    // 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->getZExtSize();
 
    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->isPackedVectorBoolType(*this)
                ? 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() == VectorKind::SveFixedLengthData)
      // Adjust the alignment for fixed-length SVE vectors. This is important
      // for non-power-of-2 vector lengths.
      Align = 128;
    else if (VT->getVectorKind() == VectorKind::SveFixedLengthPredicate)
      // Adjust the alignment for fixed-length SVE predicates.
      Align = 16;
    else if (VT->getVectorKind() == VectorKind::RVVFixedLengthData ||
             VT->getVectorKind() == VectorKind::RVVFixedLengthMask ||
             VT->getVectorKind() == VectorKind::RVVFixedLengthMask_1 ||
             VT->getVectorKind() == VectorKind::RVVFixedLengthMask_2 ||
             VT->getVectorKind() == VectorKind::RVVFixedLengthMask_4)
      // Adjust the alignment for fixed-length RVV vectors.
      Align = std::min<unsigned>(64, Width);
    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().OpenMPIsTargetDevice)) &&
                 AuxTarget->hasBFloat16Type()) {
        Width = AuxTarget->getBFloat16Width();
        Align = AuxTarget->getBFloat16Align();
      }
      break;
    case BuiltinType::Float16:
    case BuiltinType::Half:
      if (Target->hasFloat16Type() || !getLangOpts().OpenMP ||
          !getLangOpts().OpenMPIsTargetDevice) {
        Width = Target->getHalfWidth();
        Align = Target->getHalfAlign();
      } else {
        assert(getLangOpts().OpenMP && getLangOpts().OpenMPIsTargetDevice &&
               "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().OpenMPIsTargetDevice &&
          (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().OpenMPIsTargetDevice) {
        Width = Target->getFloat128Width();
        Align = Target->getFloat128Align();
      } else {
        assert(getLangOpts().OpenMP && getLangOpts().OpenMPIsTargetDevice &&
               "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)                    \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 128;                                                               \
    break;
#define SVE_PREDICATE_TYPE(Name, MangledName, Id, SingletonId)                 \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 16;                                                                \
    break;
#define SVE_OPAQUE_TYPE(Name, MangledName, Id, SingletonId)                    \
  case BuiltinType::Id:                                                        \
    Width = 0;                                                                 \
    Align = 16;                                                                \
    break;
#define SVE_SCALAR_TYPE(Name, MangledName, Id, SingletonId, Bits)              \
  case BuiltinType::Id:                                                        \
    Width = Bits;                                                              \
    Align = Bits;                                                              \
    break;
#include "clang/Basic/AArch64ACLETypes.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, IsBF)                                            \
  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"
#define AMDGPU_TYPE(NAME, ID, SINGLETONID, WIDTH, ALIGN)                       \
  case BuiltinType::ID:                                                        \
    Width = WIDTH;                                                             \
    Align = ALIGN;                                                             \
    break;
#include "clang/Basic/AMDGPUTypes.def"
#define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
#include "clang/Basic/HLSLIntangibleTypes.def"
      Width = Target->getPointerWidth(LangAS::Default);
      Align = Target->getPointerAlign(LangAS::Default);
      break;
    }
    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 = Target->getBitIntAlign(EIT->getNumBits());
    Width = Target->getBitIntWidth(EIT->getNumBits());
    break;
  }
  case Type::Record:
  case Type::Enum: {
    const auto *TT = cast<TagType>(T);
    const TagDecl *TD = TT->getDecl()->getDefinitionOrSelf();
 
    if (TD->isInvalidDecl()) {
      Width = 8;
      Align = 8;
      break;
    }
 
    if (isa<EnumType>(TT)) {
      const EnumDecl *ED = cast<EnumDecl>(TD);
      TypeInfo Info =
          getTypeInfo(ED->getIntegerType()->getUnqualifiedDesugaredType());
      if (unsigned AttrAlign = ED->getMaxAlignment()) {
        Info.Align = AttrAlign;
        Info.AlignRequirement = AlignRequirementKind::RequiredByEnum;
      }
      return Info;
    }
 
    const auto *RD = cast<RecordDecl>(TD);
    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::Attributed:
    return getTypeInfo(
                  cast<AttributedType>(T)->getEquivalentType().getTypePtr());
 
  case Type::CountAttributed:
    return getTypeInfo(cast<CountAttributedType>(T)->desugar().getTypePtr());
 
  case Type::BTFTagAttributed:
    return getTypeInfo(
        cast<BTFTagAttributedType>(T)->getWrappedType().getTypePtr());
 
  case Type::HLSLAttributedResource:
    return getTypeInfo(
        cast<HLSLAttributedResourceType>(T)->getWrappedType().getTypePtr());
 
  case Type::HLSLInlineSpirv: {
    const auto *ST = cast<HLSLInlineSpirvType>(T);
    // Size is specified in bytes, convert to bits
    Width = ST->getSize() * 8;
    Align = ST->getAlignment();
    if (Width == 0 && Align == 0) {
      // We are defaulting to laying out opaque SPIR-V types as 32-bit ints.
      Width = 32;
      Align = 32;
    }
    break;
  }
 
  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::PredefinedSugar:
    return getTypeInfo(cast<PredefinedSugarType>(T)->desugar().getTypePtr());
 
  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->getAsCanonical<RecordType>()) {
    const ASTRecordLayout &Layout = getASTRecordLayout(RT->getDecl());
    UnadjustedAlign = toBits(Layout.getUnadjustedAlignment());
  } else if (const auto *ObjCI = T->getAsCanonical<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 *RD = T->getAsRecordDecl()) {
    // 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 *ED = T->getAsEnumDecl())
    T = ED->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 VarDecl *VD) const {
  uint64_t TypeSize = getTypeSize(T.getTypePtr());
  return std::max(getPreferredTypeAlign(T),
                  getMinGlobalAlignOfVar(TypeSize, VD));
}
 
/// getAlignOfGlobalVarInChars - Return the alignment in characters that
/// should be given to a global variable of the specified type.
CharUnits ASTContext::getAlignOfGlobalVarInChars(QualType T,
                                                 const VarDecl *VD) const {
  return toCharUnitsFromBits(getAlignOfGlobalVar(T, VD));
}
 
unsigned ASTContext::getMinGlobalAlignOfVar(uint64_t Size,
                                            const VarDecl *VD) const {
  // Make the default handling as that of a non-weak definition in the
  // current translation unit.
  bool HasNonWeakDef = !VD || (VD->hasDefinition() && !VD->isWeak());
  return getTargetInfo().getMinGlobalAlign(Size, HasNonWeakDef);
}
 
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(Context.getCanonicalTagType(RD));
 
  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 (const auto *RD = Field->getType()->getAsRecordDecl();
      RD && !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();
    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);
 
  assert((Ty->isVoidType() || !Ty->isIncompleteType()) &&
         "hasUniqueObjectRepresentations should not be called with an "
         "incomplete type");
 
  // (9.1) - T is trivially copyable...
  if (CheckIfTriviallyCopyable && !Ty.isTriviallyCopyableType(*this))
    return false;
 
  // All integrals and enums are unique.
  if (Ty->isIntegralOrEnumerationType()) {
    // Address discriminated integer types are not unique.
    if (Ty.hasAddressDiscriminatedPointerAuth())
      return false;
    // 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 !Ty.hasAddressDiscriminatedPointerAuth();
 
  if (const auto *MPT = Ty->getAs<MemberPointerType>())
    return !ABI->getMemberPointerInfo(MPT).HasPadding;
 
  if (const auto *Record = Ty->getAsRecordDecl()) {
    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 *TSI = CreateTypeSourceInfo(T);
  TSI->getTypeLoc().initialize(const_cast<ASTContext &>(*this), L);
  return TSI;
}
 
const ASTRecordLayout &
ASTContext::getASTObjCInterfaceLayout(const ObjCInterfaceDecl *D) const {
  return getObjCLayout(D);
}
 
static auto getCanonicalTemplateArguments(const ASTContext &C,
                                          ArrayRef<TemplateArgument> Args,
                                          bool &AnyNonCanonArgs) {
  SmallVector<TemplateArgument, 16> CanonArgs(Args);
  AnyNonCanonArgs |= C.canonicalizeTemplateArguments(CanonArgs);
  return CanonArgs;
}
 
bool ASTContext::canonicalizeTemplateArguments(
    MutableArrayRef<TemplateArgument> Args) const {
  bool AnyNonCanonArgs = false;
  for (auto &Arg : Args) {
    TemplateArgument OrigArg = Arg;
    Arg = getCanonicalTemplateArgument(Arg);
    AnyNonCanonArgs |= !Arg.structurallyEquals(OrigArg);
  }
  return AnyNonCanonArgs;
}
 
//===----------------------------------------------------------------------===//
//                   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, alignof(ExtQuals)) 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;
 
  QualifierCollector Quals;
  const Type *TypeNode;
  // For arrays, strip the qualifier off the element type, then reconstruct the
  // array type
  if (T.getTypePtr()->isArrayType()) {
    T = getUnqualifiedArrayType(T, Quals);
    TypeNode = T.getTypePtr();
  } else {
    // If we are composing extended qualifiers together, merge together
    // into one ExtQuals node.
    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());
}
 
uint16_t
ASTContext::getPointerAuthVTablePointerDiscriminator(const CXXRecordDecl *RD) {
  assert(RD->isPolymorphic() &&
         "Attempted to get vtable pointer discriminator on a monomorphic type");
  std::unique_ptr<MangleContext> MC(createMangleContext());
  SmallString<256> Str;
  llvm::raw_svector_ostream Out(Str);
  MC->mangleCXXVTable(RD, Out);
  return llvm::getPointerAuthStableSipHash(Str);
}
 
/// Encode a function type for use in the discriminator of a function pointer
/// type. We can't use the itanium scheme for this since C has quite permissive
/// rules for type compatibility that we need to be compatible with.
///
/// Formally, this function associates every function pointer type T with an
/// encoded string E(T). Let the equivalence relation T1 ~ T2 be defined as
/// E(T1) == E(T2). E(T) is part of the ABI of values of type T. C type
/// compatibility requires equivalent treatment under the ABI, so
/// CCompatible(T1, T2) must imply E(T1) == E(T2), that is, CCompatible must be
/// a subset of ~. Crucially, however, it must be a proper subset because
/// CCompatible is not an equivalence relation: for example, int[] is compatible
/// with both int[1] and int[2], but the latter are not compatible with each
/// other. Therefore this encoding function must be careful to only distinguish
/// types if there is no third type with which they are both required to be
/// compatible.
static void encodeTypeForFunctionPointerAuth(const ASTContext &Ctx,
                                             raw_ostream &OS, QualType QT) {
  // FIXME: Consider address space qualifiers.
  const Type *T = QT.getCanonicalType().getTypePtr();
 
  // FIXME: Consider using the C++ type mangling when we encounter a construct
  // that is incompatible with C.
 
  switch (T->getTypeClass()) {
  case Type::Atomic:
    return encodeTypeForFunctionPointerAuth(
        Ctx, OS, cast<AtomicType>(T)->getValueType());
 
  case Type::LValueReference:
    OS << "R";
    encodeTypeForFunctionPointerAuth(Ctx, OS,
                                     cast<ReferenceType>(T)->getPointeeType());
    return;
  case Type::RValueReference:
    OS << "O";
    encodeTypeForFunctionPointerAuth(Ctx, OS,
                                     cast<ReferenceType>(T)->getPointeeType());
    return;
 
  case Type::Pointer:
    // C11 6.7.6.1p2:
    //   For two pointer types to be compatible, both shall be identically
    //   qualified and both shall be pointers to compatible types.
    // FIXME: we should also consider pointee types.
    OS << "P";
    return;
 
  case Type::ObjCObjectPointer:
  case Type::BlockPointer:
    OS << "P";
    return;
 
  case Type::Complex:
    OS << "C";
    return encodeTypeForFunctionPointerAuth(
        Ctx, OS, cast<ComplexType>(T)->getElementType());
 
  case Type::VariableArray:
  case Type::ConstantArray:
  case Type::IncompleteArray:
  case Type::ArrayParameter:
    // C11 6.7.6.2p6:
    //   For two array types to be compatible, both shall have compatible
    //   element types, and if both size specifiers are present, and are integer
    //   constant expressions, then both size specifiers shall have the same
    //   constant value [...]
    //
    // So since ElemType[N] has to be compatible ElemType[], we can't encode the
    // width of the array.
    OS << "A";
    return encodeTypeForFunctionPointerAuth(
        Ctx, OS, cast<ArrayType>(T)->getElementType());
 
  case Type::ObjCInterface:
  case Type::ObjCObject:
    OS << "<objc_object>";
    return;
 
  case Type::Enum: {
    // C11 6.7.2.2p4:
    //   Each enumerated type shall be compatible with char, a signed integer
    //   type, or an unsigned integer type.
    //
    // So we have to treat enum types as integers.
    QualType UnderlyingType = T->castAsEnumDecl()->getIntegerType();
    return encodeTypeForFunctionPointerAuth(
        Ctx, OS, UnderlyingType.isNull() ? Ctx.IntTy : UnderlyingType);
  }
 
  case Type::FunctionNoProto:
  case Type::FunctionProto: {
    // C11 6.7.6.3p15:
    //   For two function types to be compatible, both shall specify compatible
    //   return types. Moreover, the parameter type lists, if both are present,
    //   shall agree in the number of parameters and in the use of the ellipsis
    //   terminator; corresponding parameters shall have compatible types.
    //
    // That paragraph goes on to describe how unprototyped functions are to be
    // handled, which we ignore here. Unprototyped function pointers are hashed
    // as though they were prototyped nullary functions since thats probably
    // what the user meant. This behavior is non-conforming.
    // FIXME: If we add a "custom discriminator" function type attribute we
    // should encode functions as their discriminators.
    OS << "F";
    const auto *FuncType = cast<FunctionType>(T);
    encodeTypeForFunctionPointerAuth(Ctx, OS, FuncType->getReturnType());
    if (const auto *FPT = dyn_cast<FunctionProtoType>(FuncType)) {
      for (QualType Param : FPT->param_types()) {
        Param = Ctx.getSignatureParameterType(Param);
        encodeTypeForFunctionPointerAuth(Ctx, OS, Param);
      }
      if (FPT->isVariadic())
        OS << "z";
    }
    OS << "E";
    return;
  }
 
  case Type::MemberPointer: {
    OS << "M";
    const auto *MPT = T->castAs<MemberPointerType>();
    encodeTypeForFunctionPointerAuth(
        Ctx, OS, QualType(MPT->getQualifier().getAsType(), 0));
    encodeTypeForFunctionPointerAuth(Ctx, OS, MPT->getPointeeType());
    return;
  }
  case Type::ExtVector:
  case Type::Vector:
    OS << "Dv" << Ctx.getTypeSizeInChars(T).getQuantity();
    break;
 
  // Don't bother discriminating based on these types.
  case Type::Pipe:
  case Type::BitInt:
  case Type::ConstantMatrix:
    OS << "?";
    return;
 
  case Type::Builtin: {
    const auto *BTy = T->castAs<BuiltinType>();
    switch (BTy->getKind()) {
#define SIGNED_TYPE(Id, SingletonId)                                           \
  case BuiltinType::Id:                                                        \
    OS << "i";                                                                 \
    return;
#define UNSIGNED_TYPE(Id, SingletonId)                                         \
  case BuiltinType::Id:                                                        \
    OS << "i";                                                                 \
    return;
#define PLACEHOLDER_TYPE(Id, SingletonId) case BuiltinType::Id:
#define BUILTIN_TYPE(Id, SingletonId)
#include "clang/AST/BuiltinTypes.def"
      llvm_unreachable("placeholder types should not appear here.");
 
    case BuiltinType::Half:
      OS << "Dh";
      return;
    case BuiltinType::Float:
      OS << "f";
      return;
    case BuiltinType::Double:
      OS << "d";
      return;
    case BuiltinType::LongDouble:
      OS << "e";
      return;
    case BuiltinType::Float16:
      OS << "DF16_";
      return;
    case BuiltinType::Float128:
      OS << "g";
      return;
 
    case BuiltinType::Void:
      OS << "v";
      return;
 
    case BuiltinType::ObjCId:
    case BuiltinType::ObjCClass:
    case BuiltinType::ObjCSel:
    case BuiltinType::NullPtr:
      OS << "P";
      return;
 
    // Don't bother discriminating based on OpenCL types.
    case BuiltinType::OCLSampler:
    case BuiltinType::OCLEvent:
    case BuiltinType::OCLClkEvent:
    case BuiltinType::OCLQueue:
    case BuiltinType::OCLReserveID:
    case BuiltinType::BFloat16:
    case BuiltinType::VectorQuad:
    case BuiltinType::VectorPair:
    case BuiltinType::DMR1024:
    case BuiltinType::DMR2048:
      OS << "?";
      return;
 
    // Don't bother discriminating based on these seldom-used types.
    case BuiltinType::Ibm128:
      return;
#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix)                   \
  case BuiltinType::Id:                                                        \
    return;
#include "clang/Basic/OpenCLImageTypes.def"
#define EXT_OPAQUE_TYPE(ExtType, Id, Ext)                                      \
  case BuiltinType::Id:                                                        \
    return;
#include "clang/Basic/OpenCLExtensionTypes.def"
#define SVE_TYPE(Name, Id, SingletonId)                                        \
  case BuiltinType::Id:                                                        \
    return;
#include "clang/Basic/AArch64ACLETypes.def"
#define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId)                            \
  case BuiltinType::Id:                                                        \
    return;
#include "clang/Basic/HLSLIntangibleTypes.def"
    case BuiltinType::Dependent:
      llvm_unreachable("should never get here");
#define AMDGPU_TYPE(Name, Id, SingletonId, Width, Align) case BuiltinType::Id:
#include "clang/Basic/AMDGPUTypes.def"
    case BuiltinType::WasmExternRef:
#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
#include "clang/Basic/RISCVVTypes.def"
      llvm_unreachable("not yet implemented");
    }
    llvm_unreachable("should never get here");
  }
  case Type::Record: {
    const RecordDecl *RD = T->castAsCanonical<RecordType>()->getDecl();
    const IdentifierInfo *II = RD->getIdentifier();
 
    // In C++, an immediate typedef of an anonymous struct or union
    // is considered to name it for ODR purposes, but C's specification
    // of type compatibility does not have a similar rule.  Using the typedef
    // name in function type discriminators anyway, as we do here,
    // therefore technically violates the C standard: two function pointer
    // types defined in terms of two typedef'd anonymous structs with
    // different names are formally still compatible, but we are assigning
    // them different discriminators and therefore incompatible ABIs.
    //
    // This is a relatively minor violation that significantly improves
    // discrimination in some cases and has not caused problems in
    // practice.  Regardless, it is now part of the ABI in places where
    // function type discrimination is used, and it can no longer be
    // changed except on new platforms.
 
    if (!II)
      if (const TypedefNameDecl *Typedef = RD->getTypedefNameForAnonDecl())
        II = Typedef->getDeclName().getAsIdentifierInfo();
 
    if (!II) {
      OS << "<anonymous_record>";
      return;
    }
    OS << II->getLength() << II->getName();
    return;
  }
  case Type::HLSLAttributedResource:
  case Type::HLSLInlineSpirv:
    llvm_unreachable("should never get here");
    break;
  case Type::DeducedTemplateSpecialization:
  case Type::Auto:
#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
#define DEPENDENT_TYPE(Class, Base) case Type::Class:
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
#define ABSTRACT_TYPE(Class, Base)
#define TYPE(Class, Base)
#include "clang/AST/TypeNodes.inc"
    llvm_unreachable("unexpected non-canonical or dependent type!");
    return;
  }
}
 
uint16_t ASTContext::getPointerAuthTypeDiscriminator(QualType T) {
  assert(!T->isDependentType() &&
         "cannot compute type discriminator of a dependent type");
  SmallString<256> Str;
  llvm::raw_svector_ostream Out(Str);
 
  if (T->isFunctionPointerType() || T->isFunctionReferenceType())
    T = T->getPointeeType();
 
  if (T->isFunctionType()) {
    encodeTypeForFunctionPointerAuth(*this, Out, T);
  } else {
    T = T.getUnqualifiedType();
    // Calls to member function pointers don't need to worry about
    // language interop or the laxness of the C type compatibility rules.
    // We just mangle the member pointer type directly, which is
    // implicitly much stricter about type matching. However, we do
    // strip any top-level exception specification before this mangling.
    // C++23 requires calls to work when the function type is convertible
    // to the pointer type by a function pointer conversion, which can
    // change the exception specification. This does not technically
    // require the exception specification to not affect representation,
    // because the function pointer conversion is still always a direct
    // value conversion and therefore an opportunity to resign the
    // pointer. (This is in contrast to e.g. qualification conversions,
    // which can be applied in nested pointer positions, effectively
    // requiring qualified and unqualified representations to match.)
    // However, it is pragmatic to ignore exception specifications
    // because it allows a certain amount of `noexcept` mismatching
    // to not become a visible ODR problem. This also leaves some
    // room for the committee to add laxness to function pointer
    // conversions in future standards.
    if (auto *MPT = T->getAs<MemberPointerType>())
      if (MPT->isMemberFunctionPointer()) {
        QualType PointeeType = MPT->getPointeeType();
        if (PointeeType->castAs<FunctionProtoType>()->getExceptionSpecType() !=
            EST_None) {
          QualType FT = getFunctionTypeWithExceptionSpec(PointeeType, EST_None);
          T = getMemberPointerType(FT, MPT->getQualifier(),
                                   MPT->getMostRecentCXXRecordDecl());
        }
      }
    std::unique_ptr<MangleContext> MC(createMangleContext());
    MC->mangleCanonicalTypeName(T, Out);
  }
 
  return llvm::getPointerAuthStableSipHash(Str);
}
 
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;
}
 
QualType ASTContext::getCountAttributedType(
    QualType WrappedTy, Expr *CountExpr, bool CountInBytes, bool OrNull,
    ArrayRef<TypeCoupledDeclRefInfo> DependentDecls) const {
  assert(WrappedTy->isPointerType() || WrappedTy->isArrayType());
 
  llvm::FoldingSetNodeID ID;
  CountAttributedType::Profile(ID, WrappedTy, CountExpr, CountInBytes, OrNull);
 
  void *InsertPos = nullptr;
  CountAttributedType *CATy =
      CountAttributedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (CATy)
    return QualType(CATy, 0);
 
  QualType CanonTy = getCanonicalType(WrappedTy);
  size_t Size = CountAttributedType::totalSizeToAlloc<TypeCoupledDeclRefInfo>(
      DependentDecls.size());
  CATy = (CountAttributedType *)Allocate(Size, TypeAlignment);
  new (CATy) CountAttributedType(WrappedTy, CanonTy, CountExpr, CountInBytes,
                                 OrNull, DependentDecls);
  Types.push_back(CATy);
  CountAttributedTypes.InsertNode(CATy, InsertPos);
 
  return QualType(CATy, 0);
}
 
QualType
ASTContext::adjustType(QualType Orig,
                       llvm::function_ref<QualType(QualType)> Adjust) const {
  switch (Orig->getTypeClass()) {
  case Type::Attributed: {
    const auto *AT = cast<AttributedType>(Orig);
    return getAttributedType(AT->getAttrKind(),
                             adjustType(AT->getModifiedType(), Adjust),
                             adjustType(AT->getEquivalentType(), Adjust),
                             AT->getAttr());
  }
 
  case Type::BTFTagAttributed: {
    const auto *BTFT = dyn_cast<BTFTagAttributedType>(Orig);
    return getBTFTagAttributedType(BTFT->getAttr(),
                                   adjustType(BTFT->getWrappedType(), Adjust));
  }
 
  case Type::Paren:
    return getParenType(
        adjustType(cast<ParenType>(Orig)->getInnerType(), Adjust));
 
  case Type::Adjusted: {
    const auto *AT = cast<AdjustedType>(Orig);
    return getAdjustedType(AT->getOriginalType(),
                           adjustType(AT->getAdjustedType(), Adjust));
  }
 
  case Type::MacroQualified: {
    const auto *MQT = cast<MacroQualifiedType>(Orig);
    return getMacroQualifiedType(adjustType(MQT->getUnderlyingType(), Adjust),
                                 MQT->getMacroIdentifier());
  }
 
  default:
    return Adjust(Orig);
  }
}
 
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());
}
 
QualType ASTContext::adjustFunctionResultType(QualType FunctionType,
                                              QualType ResultType) {
  return adjustType(FunctionType, [&](QualType Orig) {
    if (const auto *FNPT = Orig->getAs<FunctionNoProtoType>())
      return getFunctionNoProtoType(ResultType, FNPT->getExtInfo());
 
    const auto *FPT = Orig->castAs<FunctionProtoType>();
    return getFunctionType(ResultType, FPT->getParamTypes(),
                           FPT->getExtProtoInfo());
  });
}
 
void ASTContext::adjustDeducedFunctionResultType(FunctionDecl *FD,
                                                 QualType ResultType) {
  FD = FD->getMostRecentDecl();
  while (true) {
    FD->setType(adjustFunctionResultType(FD->getType(), ResultType));
    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 {
  return adjustType(Orig, [&](QualType Ty) {
    const auto *Proto = Ty->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));
}
 
QualType ASTContext::getFunctionTypeWithoutParamABIs(QualType T) const {
  if (const auto *Proto = T->getAs<FunctionProtoType>()) {
    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
    EPI.ExtParameterInfos = nullptr;
    return getFunctionType(Proto->getReturnType(), Proto->param_types(), EPI);
  }
  return T;
}
 
bool ASTContext::hasSameFunctionTypeIgnoringParamABI(QualType T,
                                                     QualType U) const {
  return hasSameType(T, U) || hasSameType(getFunctionTypeWithoutParamABIs(T),
                                          getFunctionTypeWithoutParamABIs(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, alignof(ComplexType)) 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, alignof(PointerType)) 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, alignof(AdjustedType))
      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, alignof(DecayedType)) 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);
}
 
QualType ASTContext::getArrayParameterType(QualType Ty) const {
  if (Ty->isArrayParameterType())
    return Ty;
  assert(Ty->isConstantArrayType() && "Ty must be an array type.");
  QualType DTy = Ty.getDesugaredType(*this);
  const auto *ATy = cast<ConstantArrayType>(DTy);
  llvm::FoldingSetNodeID ID;
  ATy->Profile(ID, *this, ATy->getElementType(), ATy->getZExtSize(),
               ATy->getSizeExpr(), ATy->getSizeModifier(),
               ATy->getIndexTypeQualifiers().getAsOpaqueValue());
  void *InsertPos = nullptr;
  ArrayParameterType *AT =
      ArrayParameterTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (AT)
    return QualType(AT, 0);
 
  QualType Canonical;
  if (!DTy.isCanonical()) {
    Canonical = getArrayParameterType(getCanonicalType(Ty));
 
    // Get the new insert position for the node we care about.
    AT = ArrayParameterTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!AT && "Shouldn't be in the map!");
  }
 
  AT = new (*this, alignof(ArrayParameterType))
      ArrayParameterType(ATy, Canonical);
  Types.push_back(AT);
  ArrayParameterTypes.InsertNode(AT, InsertPos);
  return QualType(AT, 0);
}
 
/// 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, alignof(BlockPointerType)) 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, alignof(LValueReferenceType))
      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, alignof(RValueReferenceType))
      RValueReferenceType(T, Canonical);
  Types.push_back(New);
  RValueReferenceTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
QualType ASTContext::getMemberPointerType(QualType T,
                                          NestedNameSpecifier Qualifier,
                                          const CXXRecordDecl *Cls) const {
  if (!Qualifier) {
    assert(Cls && "At least one of Qualifier or Cls must be provided");
    Qualifier = NestedNameSpecifier(getCanonicalTagType(Cls).getTypePtr());
  } else if (!Cls) {
    Cls = Qualifier.getAsRecordDecl();
  }
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  MemberPointerType::Profile(ID, T, Qualifier, Cls);
 
  void *InsertPos = nullptr;
  if (MemberPointerType *PT =
      MemberPointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(PT, 0);
 
  NestedNameSpecifier CanonicalQualifier = [&] {
    if (!Cls)
      return Qualifier.getCanonical();
    NestedNameSpecifier R(getCanonicalTagType(Cls).getTypePtr());
    assert(R.isCanonical());
    return R;
  }();
  // 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() || Qualifier != CanonicalQualifier) {
    Canonical =
        getMemberPointerType(getCanonicalType(T), CanonicalQualifier, Cls);
    assert(!cast<MemberPointerType>(Canonical)->isSugared());
    // Get the new insert position for the node we care about.
    [[maybe_unused]] MemberPointerType *NewIP =
        MemberPointerTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!");
  }
  auto *New = new (*this, alignof(MemberPointerType))
      MemberPointerType(T, Qualifier, 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,
                                          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.getZExtValue(), 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;
  }
 
  auto *New = ConstantArrayType::Create(*this, 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::TemplateTypeParm:
  case Type::SubstTemplateTypeParmPack:
  case Type::SubstBuiltinTemplatePack:
  case Type::Auto:
  case Type::DeducedTemplateSpecialization:
  case Type::PackExpansion:
  case Type::PackIndexing:
  case Type::BitInt:
  case Type::DependentBitInt:
  case Type::ArrayParameter:
  case Type::HLSLAttributedResource:
  case Type::HLSLInlineSpirv:
    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());
    break;
  }
 
  // Turn incomplete types into [*] types.
  case Type::IncompleteArray: {
    const auto *iat = cast<IncompleteArrayType>(ty);
    result =
        getVariableArrayType(getVariableArrayDecayedType(iat->getElementType()),
                             /*size*/ nullptr, ArraySizeModifier::Normal,
                             iat->getIndexTypeCVRQualifiers());
    break;
  }
 
  // Turn VLA types into [*] types.
  case Type::VariableArray: {
    const auto *vat = cast<VariableArrayType>(ty);
    result =
        getVariableArrayType(getVariableArrayDecayedType(vat->getElementType()),
                             /*size*/ nullptr, ArraySizeModifier::Star,
                             vat->getIndexTypeCVRQualifiers());
    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,
                                          ArraySizeModifier ASM,
                                          unsigned IndexTypeQuals) 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);
    Canon = getQualifiedType(Canon, canonSplit.Quals);
  }
 
  auto *New = new (*this, alignof(VariableArrayType))
      VariableArrayType(EltTy, Canon, NumElts, ASM, IndexTypeQuals);
 
  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,
                                       ArraySizeModifier ASM,
                                       unsigned elementTypeQuals) const {
  assert((!numElements || numElements->isTypeDependent() ||
          numElements->isValueDependent()) &&
         "Size must be type- or value-dependent!");
 
  SplitQualType canonElementType = getCanonicalType(elementType).split();
 
  void *insertPos = nullptr;
  llvm::FoldingSetNodeID ID;
  DependentSizedArrayType::Profile(
      ID, *this, numElements ? QualType(canonElementType.Ty, 0) : elementType,
      ASM, elementTypeQuals, numElements);
 
  // Look for an existing type with these properties.
  DependentSizedArrayType *canonTy =
    DependentSizedArrayTypes.FindNodeOrInsertPos(ID, insertPos);
 
  // Dependently-sized array types that do not have a specified number
  // of elements will have their sizes deduced from a dependent
  // initializer.
  if (!numElements) {
    if (canonTy)
      return QualType(canonTy, 0);
 
    auto *newType = new (*this, alignof(DependentSizedArrayType))
        DependentSizedArrayType(elementType, QualType(), numElements, ASM,
                                elementTypeQuals);
    DependentSizedArrayTypes.InsertNode(newType, insertPos);
    Types.push_back(newType);
    return QualType(newType, 0);
  }
 
  // If we don't have one, build one.
  if (!canonTy) {
    canonTy = new (*this, alignof(DependentSizedArrayType))
        DependentSizedArrayType(QualType(canonElementType.Ty, 0), QualType(),
                                numElements, ASM, elementTypeQuals);
    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, alignof(DependentSizedArrayType))
      DependentSizedArrayType(elementType, canon, numElements, ASM,
                              elementTypeQuals);
  Types.push_back(sugaredType);
  return QualType(sugaredType, 0);
}
 
QualType ASTContext::getIncompleteArrayType(QualType elementType,
                                            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, alignof(IncompleteArrayType))
      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");
 
#define SVE_VECTOR_TYPE_INT(Name, MangledName, Id, SingletonId, NumEls,        \
                            ElBits, NF, IsSigned)                              \
  case BuiltinType::Id:                                                        \
    return {getIntTypeForBitwidth(ElBits, IsSigned),                           \
            llvm::ElementCount::getScalable(NumEls), NF};
#define SVE_VECTOR_TYPE_FLOAT(Name, MangledName, Id, SingletonId, NumEls,      \
                              ElBits, NF)                                      \
  case BuiltinType::Id:                                                        \
    return {ElBits == 16 ? HalfTy : (ElBits == 32 ? FloatTy : DoubleTy),       \
            llvm::ElementCount::getScalable(NumEls), NF};
#define SVE_VECTOR_TYPE_BFLOAT(Name, MangledName, Id, SingletonId, NumEls,     \
                               ElBits, NF)                                     \
  case BuiltinType::Id:                                                        \
    return {BFloat16Ty, llvm::ElementCount::getScalable(NumEls), NF};
#define SVE_VECTOR_TYPE_MFLOAT(Name, MangledName, Id, SingletonId, NumEls,     \
                               ElBits, NF)                                     \
  case BuiltinType::Id:                                                        \
    return {MFloat8Ty, llvm::ElementCount::getScalable(NumEls), NF};
#define SVE_PREDICATE_TYPE_ALL(Name, MangledName, Id, SingletonId, NumEls, NF) \
  case BuiltinType::Id:                                                        \
    return {BoolTy, llvm::ElementCount::getScalable(NumEls), NF};
#include "clang/Basic/AArch64ACLETypes.def"
 
#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_VECTOR_TYPE_BFLOAT(Name, Id, SingletonId, NumEls, ElBits, NF)      \
  case BuiltinType::Id:                                                        \
    return {BFloat16Ty, 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 {
  auto K = llvm::ScalableVecTyKey{EltTy, NumElts, NumFields};
  if (auto It = ScalableVecTyMap.find(K); It != ScalableVecTyMap.end())
    return It->second;
 
  if (Target->hasAArch64ACLETypes()) {
    uint64_t EltTySize = getTypeSize(EltTy);
 
#define SVE_VECTOR_TYPE_INT(Name, MangledName, Id, SingletonId, NumEls,        \
                            ElBits, NF, IsSigned)                              \
  if (EltTy->hasIntegerRepresentation() && !EltTy->isBooleanType() &&          \
      EltTy->hasSignedIntegerRepresentation() == IsSigned &&                   \
      EltTySize == ElBits && NumElts == (NumEls * NF) && NumFields == 1) {     \
    return ScalableVecTyMap[K] = SingletonId;                                  \
  }
#define SVE_VECTOR_TYPE_FLOAT(Name, MangledName, Id, SingletonId, NumEls,      \
                              ElBits, NF)                                      \
  if (EltTy->hasFloatingRepresentation() && !EltTy->isBFloat16Type() &&        \
      EltTySize == ElBits && NumElts == (NumEls * NF) && NumFields == 1) {     \
    return ScalableVecTyMap[K] = SingletonId;                                  \
  }
#define SVE_VECTOR_TYPE_BFLOAT(Name, MangledName, Id, SingletonId, NumEls,     \
                               ElBits, NF)                                     \
  if (EltTy->hasFloatingRepresentation() && EltTy->isBFloat16Type() &&         \
      EltTySize == ElBits && NumElts == (NumEls * NF) && NumFields == 1) {     \
    return ScalableVecTyMap[K] = SingletonId;                                  \
  }
#define SVE_VECTOR_TYPE_MFLOAT(Name, MangledName, Id, SingletonId, NumEls,     \
                               ElBits, NF)                                     \
  if (EltTy->isMFloat8Type() && EltTySize == ElBits &&                         \
      NumElts == (NumEls * NF) && NumFields == 1) {                            \
    return ScalableVecTyMap[K] = SingletonId;                                  \
  }
#define SVE_PREDICATE_TYPE_ALL(Name, MangledName, Id, SingletonId, NumEls, NF) \
  if (EltTy->isBooleanType() && NumElts == (NumEls * NF) && NumFields == 1)    \
    return ScalableVecTyMap[K] = SingletonId;
#include "clang/Basic/AArch64ACLETypes.def"
  } else if (Target->hasRISCVVTypes()) {
    uint64_t EltTySize = getTypeSize(EltTy);
#define RVV_VECTOR_TYPE(Name, Id, SingletonId, NumEls, ElBits, NF, 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 && NumFields == NF)             \
    return ScalableVecTyMap[K] = SingletonId;
#define RVV_PREDICATE_TYPE(Name, Id, SingletonId, NumEls)                      \
  if (EltTy->isBooleanType() && NumElts == NumEls)                             \
    return ScalableVecTyMap[K] = 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,
                                   VectorKind VecKind) const {
  assert(vecType->isBuiltinType() ||
         (vecType->isBitIntType() &&
          // Only support _BitInt elements with byte-sized power of 2 NumBits.
          llvm::isPowerOf2_32(vecType->castAs<BitIntType>()->getNumBits())));
 
  // 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, alignof(VectorType))
      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,
                                            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, alignof(DependentVectorType)) DependentVectorType(
        VecType, QualType(Canon, 0), SizeExpr, AttrLoc, VecKind);
  } else {
    QualType CanonVecTy = getCanonicalType(VecType);
    if (CanonVecTy == VecType) {
      New = new (*this, alignof(DependentVectorType))
          DependentVectorType(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, alignof(DependentVectorType))
          DependentVectorType(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->castAs<BitIntType>()->getNumBits())));
 
  // Check if we've already instantiated a vector of this type.
  llvm::FoldingSetNodeID ID;
  VectorType::Profile(ID, vecType, NumElts, Type::ExtVector,
                      VectorKind::Generic);
  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, alignof(ExtVectorType))
      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, alignof(DependentSizedExtVectorType))
        DependentSizedExtVectorType(vecType, QualType(Canon, 0), SizeExpr,
                                    AttrLoc);
  } else {
    QualType CanonVecTy = getCanonicalType(vecType);
    if (CanonVecTy == vecType) {
      New = new (*this, alignof(DependentSizedExtVectorType))
          DependentSizedExtVectorType(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, alignof(DependentSizedExtVectorType))
          DependentSizedExtVectorType(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, getLangOpts()) &&
         "need a valid element type");
  assert(NumRows > 0 && NumRows <= LangOpts.MaxMatrixDimension &&
         NumColumns > 0 && NumColumns <= LangOpts.MaxMatrixDimension &&
         "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, alignof(ConstantMatrixType))
      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, alignof(DependentSizedMatrixType))
        DependentSizedMatrixType(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, alignof(DependentSizedMatrixType))
      DependentSizedMatrixType(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, alignof(DependentAddressSpaceType))
        DependentAddressSpaceType(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, alignof(DependentAddressSpaceType))
      DependentAddressSpaceType(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, alignof(FunctionNoProtoType))
      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::FunctionTypeExtraAttributeInfo,
      FunctionType::FunctionTypeArmAttributes, FunctionType::ExceptionType,
      Expr *, FunctionDecl *, FunctionProtoType::ExtParameterInfo, Qualifiers,
      FunctionEffect, EffectConditionExpr>(
      NumArgs, EPI.Variadic, EPI.requiresFunctionProtoTypeExtraBitfields(),
      EPI.requiresFunctionProtoTypeExtraAttributeInfo(),
      EPI.requiresFunctionProtoTypeArmAttributes(), ESH.NumExceptionType,
      ESH.NumExprPtr, ESH.NumFunctionDeclPtr,
      EPI.ExtParameterInfos ? NumArgs : 0,
      EPI.TypeQuals.hasNonFastQualifiers() ? 1 : 0, EPI.FunctionEffects.size(),
      EPI.FunctionEffects.conditions().size());
 
  auto *FTP = (FunctionProtoType *)Allocate(Size, alignof(FunctionProtoType));
  FunctionProtoType::ExtProtoInfo newEPI = EPI;
  new (FTP) FunctionProtoType(ResultTy, ArgArray, Canonical, newEPI);
  Types.push_back(FTP);
  if (!Unique)
    FunctionProtoTypes.InsertNode(FTP, InsertPos);
  if (!EPI.FunctionEffects.empty())
    AnyFunctionEffects = true;
  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, alignof(PipeType)) 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, alignof(BitIntType)) 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, alignof(DependentBitIntType))
      DependentBitIntType(IsUnsigned, NumBitsExpr);
  DependentBitIntTypes.InsertNode(New, InsertPos);
 
  Types.push_back(New);
  return QualType(New, 0);
}
 
QualType
ASTContext::getPredefinedSugarType(PredefinedSugarType::Kind KD) const {
  using Kind = PredefinedSugarType::Kind;
 
  if (auto *Target = PredefinedSugarTypes[llvm::to_underlying(KD)];
      Target != nullptr)
    return QualType(Target, 0);
 
  auto getCanonicalType = [](const ASTContext &Ctx, Kind KDI) -> QualType {
    switch (KDI) {
      // size_t (C99TC3 6.5.3.4), signed size_t (C++23 5.13.2) and
      // ptrdiff_t (C99TC3 6.5.6) Although these types are not built-in, they
      // are part of the core language and are widely used. Using
      // PredefinedSugarType makes these types as named sugar types rather than
      // standard integer types, enabling better hints and diagnostics.
    case Kind::SizeT:
      return Ctx.getFromTargetType(Ctx.Target->getSizeType());
    case Kind::SignedSizeT:
      return Ctx.getFromTargetType(Ctx.Target->getSignedSizeType());
    case Kind::PtrdiffT:
      return Ctx.getFromTargetType(Ctx.Target->getPtrDiffType(LangAS::Default));
    }
    llvm_unreachable("unexpected kind");
  };
  auto *New = new (*this, alignof(PredefinedSugarType))
      PredefinedSugarType(KD, &Idents.get(PredefinedSugarType::getName(KD)),
                          getCanonicalType(*this, static_cast<Kind>(KD)));
  Types.push_back(New);
  PredefinedSugarTypes[llvm::to_underlying(KD)] = New;
  return QualType(New, 0);
}
 
QualType ASTContext::getTypeDeclType(ElaboratedTypeKeyword Keyword,
                                     NestedNameSpecifier Qualifier,
                                     const TypeDecl *Decl) const {
  if (auto *Tag = dyn_cast<TagDecl>(Decl))
    return getTagType(Keyword, Qualifier, Tag,
                      /*OwnsTag=*/false);
  if (auto *Typedef = dyn_cast<TypedefNameDecl>(Decl))
    return getTypedefType(Keyword, Qualifier, Typedef);
  if (auto *UD = dyn_cast<UnresolvedUsingTypenameDecl>(Decl))
    return getUnresolvedUsingType(Keyword, Qualifier, UD);
 
  assert(Keyword == ElaboratedTypeKeyword::None);
  assert(!Qualifier);
  return QualType(Decl->TypeForDecl, 0);
}
 
CanQualType ASTContext::getCanonicalTypeDeclType(const TypeDecl *TD) const {
  if (auto *Tag = dyn_cast<TagDecl>(TD))
    return getCanonicalTagType(Tag);
  if (auto *TN = dyn_cast<TypedefNameDecl>(TD))
    return getCanonicalType(TN->getUnderlyingType());
  if (const auto *UD = dyn_cast<UnresolvedUsingTypenameDecl>(TD))
    return getCanonicalUnresolvedUsingType(UD);
  assert(TD->TypeForDecl);
  return TD->TypeForDecl->getCanonicalTypeUnqualified();
}
 
QualType ASTContext::getTypeDeclType(const TypeDecl *Decl) const {
  if (const auto *TD = dyn_cast<TagDecl>(Decl))
    return getCanonicalTagType(TD);
  if (const auto *TD = dyn_cast<TypedefNameDecl>(Decl);
      isa_and_nonnull<TypedefDecl, TypeAliasDecl>(TD))
    return getTypedefType(ElaboratedTypeKeyword::None,
                          /*Qualifier=*/std::nullopt, TD);
  if (const auto *Using = dyn_cast<UnresolvedUsingTypenameDecl>(Decl))
    return getCanonicalUnresolvedUsingType(Using);
 
  assert(Decl->TypeForDecl);
  return QualType(Decl->TypeForDecl, 0);
}
 
/// getTypedefType - Return the unique reference to the type for the
/// specified typedef name decl.
QualType
ASTContext::getTypedefType(ElaboratedTypeKeyword Keyword,
                           NestedNameSpecifier Qualifier,
                           const TypedefNameDecl *Decl, QualType UnderlyingType,
                           std::optional<bool> TypeMatchesDeclOrNone) const {
  if (!TypeMatchesDeclOrNone) {
    QualType DeclUnderlyingType = Decl->getUnderlyingType();
    assert(!DeclUnderlyingType.isNull());
    if (UnderlyingType.isNull())
      UnderlyingType = DeclUnderlyingType;
    else
      assert(hasSameType(UnderlyingType, DeclUnderlyingType));
    TypeMatchesDeclOrNone = UnderlyingType == DeclUnderlyingType;
  } else {
    // FIXME: This is a workaround for a serialization cycle: assume the decl
    // underlying type is not available; don't touch it.
    assert(!UnderlyingType.isNull());
  }
 
  if (Keyword == ElaboratedTypeKeyword::None && !Qualifier &&
      *TypeMatchesDeclOrNone) {
    if (Decl->TypeForDecl)
      return QualType(Decl->TypeForDecl, 0);
 
    auto *NewType = new (*this, alignof(TypedefType))
        TypedefType(Type::Typedef, Keyword, Qualifier, Decl, UnderlyingType,
                    !*TypeMatchesDeclOrNone);
 
    Types.push_back(NewType);
    Decl->TypeForDecl = NewType;
    return QualType(NewType, 0);
  }
 
  llvm::FoldingSetNodeID ID;
  TypedefType::Profile(ID, Keyword, Qualifier, Decl,
                       *TypeMatchesDeclOrNone ? QualType() : UnderlyingType);
 
  void *InsertPos = nullptr;
  if (FoldingSetPlaceholder<TypedefType> *Placeholder =
          TypedefTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(Placeholder->getType(), 0);
 
  void *Mem =
      Allocate(TypedefType::totalSizeToAlloc<FoldingSetPlaceholder<TypedefType>,
                                             NestedNameSpecifier, QualType>(
                   1, !!Qualifier, !*TypeMatchesDeclOrNone),
               alignof(TypedefType));
  auto *NewType =
      new (Mem) TypedefType(Type::Typedef, Keyword, Qualifier, Decl,
                            UnderlyingType, !*TypeMatchesDeclOrNone);
  auto *Placeholder = new (NewType->getFoldingSetPlaceholder())
      FoldingSetPlaceholder<TypedefType>();
  TypedefTypes.InsertNode(Placeholder, InsertPos);
  Types.push_back(NewType);
  return QualType(NewType, 0);
}
 
QualType ASTContext::getUsingType(ElaboratedTypeKeyword Keyword,
                                  NestedNameSpecifier Qualifier,
                                  const UsingShadowDecl *D,
                                  QualType UnderlyingType) const {
  // FIXME: This is expensive to compute every time!
  if (UnderlyingType.isNull()) {
    const auto *UD = cast<UsingDecl>(D->getIntroducer());
    UnderlyingType =
        getTypeDeclType(UD->hasTypename() ? ElaboratedTypeKeyword::Typename
                                          : ElaboratedTypeKeyword::None,
                        UD->getQualifier(), cast<TypeDecl>(D->getTargetDecl()));
  }
 
  llvm::FoldingSetNodeID ID;
  UsingType::Profile(ID, Keyword, Qualifier, D, UnderlyingType);
 
  void *InsertPos = nullptr;
  if (const UsingType *T = UsingTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(T, 0);
 
  assert(!UnderlyingType.hasLocalQualifiers());
 
  assert(
      hasSameType(getCanonicalTypeDeclType(cast<TypeDecl>(D->getTargetDecl())),
                  UnderlyingType));
 
  void *Mem =
      Allocate(UsingType::totalSizeToAlloc<NestedNameSpecifier>(!!Qualifier),
               alignof(UsingType));
  UsingType *T = new (Mem) UsingType(Keyword, Qualifier, D, UnderlyingType);
  Types.push_back(T);
  UsingTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}
 
TagType *ASTContext::getTagTypeInternal(ElaboratedTypeKeyword Keyword,
                                        NestedNameSpecifier Qualifier,
                                        const TagDecl *TD, bool OwnsTag,
                                        bool IsInjected,
                                        const Type *CanonicalType,
                                        bool WithFoldingSetNode) const {
  auto [TC, Size] = [&] {
    switch (TD->getDeclKind()) {
    case Decl::Enum:
      static_assert(alignof(EnumType) == alignof(TagType));
      return std::make_tuple(Type::Enum, sizeof(EnumType));
    case Decl::ClassTemplatePartialSpecialization:
    case Decl::ClassTemplateSpecialization:
    case Decl::CXXRecord:
      static_assert(alignof(RecordType) == alignof(TagType));
      static_assert(alignof(InjectedClassNameType) == alignof(TagType));
      if (cast<CXXRecordDecl>(TD)->hasInjectedClassType())
        return std::make_tuple(Type::InjectedClassName,
                               sizeof(InjectedClassNameType));
      [[fallthrough]];
    case Decl::Record:
      return std::make_tuple(Type::Record, sizeof(RecordType));
    default:
      llvm_unreachable("unexpected decl kind");
    }
  }();
 
  if (Qualifier) {
    static_assert(alignof(NestedNameSpecifier) <= alignof(TagType));
    Size = llvm::alignTo(Size, alignof(NestedNameSpecifier)) +
           sizeof(NestedNameSpecifier);
  }
  void *Mem;
  if (WithFoldingSetNode) {
    // FIXME: It would be more profitable to tail allocate the folding set node
    // from the type, instead of the other way around, due to the greater
    // alignment requirements of the type. But this makes it harder to deal with
    // the different type node sizes. This would require either uniquing from
    // different folding sets, or having the folding setaccept a
    // contextual parameter which is not fixed at construction.
    Mem = Allocate(
        sizeof(TagTypeFoldingSetPlaceholder) +
            TagTypeFoldingSetPlaceholder::getOffset() + Size,
        std::max(alignof(TagTypeFoldingSetPlaceholder), alignof(TagType)));
    auto *T = new (Mem) TagTypeFoldingSetPlaceholder();
    Mem = T->getTagType();
  } else {
    Mem = Allocate(Size, alignof(TagType));
  }
 
  auto *T = [&, TC = TC]() -> TagType * {
    switch (TC) {
    case Type::Enum: {
      assert(isa<EnumDecl>(TD));
      auto *T = new (Mem) EnumType(TC, Keyword, Qualifier, TD, OwnsTag,
                                   IsInjected, CanonicalType);
      assert(reinterpret_cast<void *>(T) ==
                 reinterpret_cast<void *>(static_cast<TagType *>(T)) &&
             "TagType must be the first base of EnumType");
      return T;
    }
    case Type::Record: {
      assert(isa<RecordDecl>(TD));
      auto *T = new (Mem) RecordType(TC, Keyword, Qualifier, TD, OwnsTag,
                                     IsInjected, CanonicalType);
      assert(reinterpret_cast<void *>(T) ==
                 reinterpret_cast<void *>(static_cast<TagType *>(T)) &&
             "TagType must be the first base of RecordType");
      return T;
    }
    case Type::InjectedClassName: {
      auto *T = new (Mem) InjectedClassNameType(Keyword, Qualifier, TD,
                                                IsInjected, CanonicalType);
      assert(reinterpret_cast<void *>(T) ==
                 reinterpret_cast<void *>(static_cast<TagType *>(T)) &&
             "TagType must be the first base of InjectedClassNameType");
      return T;
    }
    default:
      llvm_unreachable("unexpected type class");
    }
  }();
  assert(T->getKeyword() == Keyword);
  assert(T->getQualifier() == Qualifier);
  assert(T->getDecl() == TD);
  assert(T->isInjected() == IsInjected);
  assert(T->isTagOwned() == OwnsTag);
  assert((T->isCanonicalUnqualified()
              ? QualType()
              : T->getCanonicalTypeInternal()) == QualType(CanonicalType, 0));
  Types.push_back(T);
  return T;
}
 
static const TagDecl *getNonInjectedClassName(const TagDecl *TD) {
  if (const auto *RD = dyn_cast<CXXRecordDecl>(TD);
      RD && RD->isInjectedClassName())
    return cast<TagDecl>(RD->getDeclContext());
  return TD;
}
 
CanQualType ASTContext::getCanonicalTagType(const TagDecl *TD) const {
  TD = ::getNonInjectedClassName(TD)->getCanonicalDecl();
  if (TD->TypeForDecl)
    return TD->TypeForDecl->getCanonicalTypeUnqualified();
 
  const Type *CanonicalType = getTagTypeInternal(
      ElaboratedTypeKeyword::None,
      /*Qualifier=*/std::nullopt, TD,
      /*OwnsTag=*/false, /*IsInjected=*/false, /*CanonicalType=*/nullptr,
      /*WithFoldingSetNode=*/false);
  TD->TypeForDecl = CanonicalType;
  return CanQualType::CreateUnsafe(QualType(CanonicalType, 0));
}
 
QualType ASTContext::getTagType(ElaboratedTypeKeyword Keyword,
                                NestedNameSpecifier Qualifier,
                                const TagDecl *TD, bool OwnsTag) const {
 
  const TagDecl *NonInjectedTD = ::getNonInjectedClassName(TD);
  bool IsInjected = TD != NonInjectedTD;
 
  ElaboratedTypeKeyword PreferredKeyword =
      getLangOpts().CPlusPlus ? ElaboratedTypeKeyword::None
                              : KeywordHelpers::getKeywordForTagTypeKind(
                                    NonInjectedTD->getTagKind());
 
  if (Keyword == PreferredKeyword && !Qualifier && !OwnsTag) {
    if (const Type *T = TD->TypeForDecl; T && !T->isCanonicalUnqualified())
      return QualType(T, 0);
 
    const Type *CanonicalType = getCanonicalTagType(NonInjectedTD).getTypePtr();
    const Type *T =
        getTagTypeInternal(Keyword,
                           /*Qualifier=*/std::nullopt, NonInjectedTD,
                           /*OwnsTag=*/false, IsInjected, CanonicalType,
                           /*WithFoldingSetNode=*/false);
    TD->TypeForDecl = T;
    return QualType(T, 0);
  }
 
  llvm::FoldingSetNodeID ID;
  TagTypeFoldingSetPlaceholder::Profile(ID, Keyword, Qualifier, NonInjectedTD,
                                        OwnsTag, IsInjected);
 
  void *InsertPos = nullptr;
  if (TagTypeFoldingSetPlaceholder *T =
          TagTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(T->getTagType(), 0);
 
  const Type *CanonicalType = getCanonicalTagType(NonInjectedTD).getTypePtr();
  TagType *T =
      getTagTypeInternal(Keyword, Qualifier, NonInjectedTD, OwnsTag, IsInjected,
                         CanonicalType, /*WithFoldingSetNode=*/true);
  TagTypes.InsertNode(TagTypeFoldingSetPlaceholder::fromTagType(T), InsertPos);
  return QualType(T, 0);
}
 
bool ASTContext::computeBestEnumTypes(bool IsPacked, unsigned NumNegativeBits,
                                      unsigned NumPositiveBits,
                                      QualType &BestType,
                                      QualType &BestPromotionType) {
  unsigned IntWidth = Target->getIntWidth();
  unsigned CharWidth = Target->getCharWidth();
  unsigned ShortWidth = Target->getShortWidth();
  bool EnumTooLarge = false;
  unsigned BestWidth;
  if (NumNegativeBits) {
    // If there is a negative value, figure out the smallest integer type (of
    // int/long/longlong) that fits.
    // If it's packed, check also if it fits a char or a short.
    if (IsPacked && NumNegativeBits <= CharWidth &&
        NumPositiveBits < CharWidth) {
      BestType = SignedCharTy;
      BestWidth = CharWidth;
    } else if (IsPacked && NumNegativeBits <= ShortWidth &&
               NumPositiveBits < ShortWidth) {
      BestType = ShortTy;
      BestWidth = ShortWidth;
    } else if (NumNegativeBits <= IntWidth && NumPositiveBits < IntWidth) {
      BestType = IntTy;
      BestWidth = IntWidth;
    } else {
      BestWidth = Target->getLongWidth();
 
      if (NumNegativeBits <= BestWidth && NumPositiveBits < BestWidth) {
        BestType = LongTy;
      } else {
        BestWidth = Target->getLongLongWidth();
 
        if (NumNegativeBits > BestWidth || NumPositiveBits >= BestWidth)
          EnumTooLarge = true;
        BestType = LongLongTy;
      }
    }
    BestPromotionType = (BestWidth <= IntWidth ? IntTy : BestType);
  } else {
    // If there is no negative value, figure out the smallest type that fits
    // all of the enumerator values.
    // If it's packed, check also if it fits a char or a short.
    if (IsPacked && NumPositiveBits <= CharWidth) {
      BestType = UnsignedCharTy;
      BestPromotionType = IntTy;
      BestWidth = CharWidth;
    } else if (IsPacked && NumPositiveBits <= ShortWidth) {
      BestType = UnsignedShortTy;
      BestPromotionType = IntTy;
      BestWidth = ShortWidth;
    } else if (NumPositiveBits <= IntWidth) {
      BestType = UnsignedIntTy;
      BestWidth = IntWidth;
      BestPromotionType = (NumPositiveBits == BestWidth || !LangOpts.CPlusPlus)
                              ? UnsignedIntTy
                              : IntTy;
    } else if (NumPositiveBits <= (BestWidth = Target->getLongWidth())) {
      BestType = UnsignedLongTy;
      BestPromotionType = (NumPositiveBits == BestWidth || !LangOpts.CPlusPlus)
                              ? UnsignedLongTy
                              : LongTy;
    } else {
      BestWidth = Target->getLongLongWidth();
      if (NumPositiveBits > BestWidth) {
        // This can happen with bit-precise integer types, but those are not
        // allowed as the type for an enumerator per C23 6.7.2.2p4 and p12.
        // FIXME: GCC uses __int128_t and __uint128_t for cases that fit within
        // a 128-bit integer, we should consider doing the same.
        EnumTooLarge = true;
      }
      BestType = UnsignedLongLongTy;
      BestPromotionType = (NumPositiveBits == BestWidth || !LangOpts.CPlusPlus)
                              ? UnsignedLongLongTy
                              : LongLongTy;
    }
  }
  return EnumTooLarge;
}
 
bool ASTContext::isRepresentableIntegerValue(llvm::APSInt &Value, QualType T) {
  assert((T->isIntegralType(*this) || T->isEnumeralType()) &&
         "Integral type required!");
  unsigned BitWidth = getIntWidth(T);
 
  if (Value.isUnsigned() || Value.isNonNegative()) {
    if (T->isSignedIntegerOrEnumerationType())
      --BitWidth;
    return Value.getActiveBits() <= BitWidth;
  }
  return Value.getSignificantBits() <= BitWidth;
}
 
UnresolvedUsingType *ASTContext::getUnresolvedUsingTypeInternal(
    ElaboratedTypeKeyword Keyword, NestedNameSpecifier Qualifier,
    const UnresolvedUsingTypenameDecl *D, void *InsertPos,
    const Type *CanonicalType) const {
  void *Mem = Allocate(
      UnresolvedUsingType::totalSizeToAlloc<
          FoldingSetPlaceholder<UnresolvedUsingType>, NestedNameSpecifier>(
          !!InsertPos, !!Qualifier),
      alignof(UnresolvedUsingType));
  auto *T = new (Mem) UnresolvedUsingType(Keyword, Qualifier, D, CanonicalType);
  if (InsertPos) {
    auto *Placeholder = new (T->getFoldingSetPlaceholder())
        FoldingSetPlaceholder<TypedefType>();
    TypedefTypes.InsertNode(Placeholder, InsertPos);
  }
  Types.push_back(T);
  return T;
}
 
CanQualType ASTContext::getCanonicalUnresolvedUsingType(
    const UnresolvedUsingTypenameDecl *D) const {
  D = D->getCanonicalDecl();
  if (D->TypeForDecl)
    return D->TypeForDecl->getCanonicalTypeUnqualified();
 
  const Type *CanonicalType = getUnresolvedUsingTypeInternal(
      ElaboratedTypeKeyword::None,
      /*Qualifier=*/std::nullopt, D,
      /*InsertPos=*/nullptr, /*CanonicalType=*/nullptr);
  D->TypeForDecl = CanonicalType;
  return CanQualType::CreateUnsafe(QualType(CanonicalType, 0));
}
 
QualType
ASTContext::getUnresolvedUsingType(ElaboratedTypeKeyword Keyword,
                                   NestedNameSpecifier Qualifier,
                                   const UnresolvedUsingTypenameDecl *D) const {
  if (Keyword == ElaboratedTypeKeyword::None && !Qualifier) {
    if (const Type *T = D->TypeForDecl; T && !T->isCanonicalUnqualified())
      return QualType(T, 0);
 
    const Type *CanonicalType = getCanonicalUnresolvedUsingType(D).getTypePtr();
    const Type *T =
        getUnresolvedUsingTypeInternal(ElaboratedTypeKeyword::None,
                                       /*Qualifier=*/std::nullopt, D,
                                       /*InsertPos=*/nullptr, CanonicalType);
    D->TypeForDecl = T;
    return QualType(T, 0);
  }
 
  llvm::FoldingSetNodeID ID;
  UnresolvedUsingType::Profile(ID, Keyword, Qualifier, D);
 
  void *InsertPos = nullptr;
  if (FoldingSetPlaceholder<UnresolvedUsingType> *Placeholder =
          UnresolvedUsingTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(Placeholder->getType(), 0);
  assert(InsertPos);
 
  const Type *CanonicalType = getCanonicalUnresolvedUsingType(D).getTypePtr();
  const Type *T = getUnresolvedUsingTypeInternal(Keyword, Qualifier, D,
                                                 InsertPos, CanonicalType);
  return QualType(T, 0);
}
 
QualType ASTContext::getAttributedType(attr::Kind attrKind,
                                       QualType modifiedType,
                                       QualType equivalentType,
                                       const Attr *attr) const {
  llvm::FoldingSetNodeID id;
  AttributedType::Profile(id, attrKind, modifiedType, equivalentType, attr);
 
  void *insertPos = nullptr;
  AttributedType *type = AttributedTypes.FindNodeOrInsertPos(id, insertPos);
  if (type) return QualType(type, 0);
 
  assert(!attr || attr->getKind() == attrKind);
 
  QualType canon = getCanonicalType(equivalentType);
  type = new (*this, alignof(AttributedType))
      AttributedType(canon, attrKind, attr, modifiedType, equivalentType);
 
  Types.push_back(type);
  AttributedTypes.InsertNode(type, insertPos);
 
  return QualType(type, 0);
}
 
QualType ASTContext::getAttributedType(const Attr *attr, QualType modifiedType,
                                       QualType equivalentType) const {
  return getAttributedType(attr->getKind(), modifiedType, equivalentType, attr);
}
 
QualType ASTContext::getAttributedType(NullabilityKind nullability,
                                       QualType modifiedType,
                                       QualType equivalentType) {
  switch (nullability) {
  case NullabilityKind::NonNull:
    return getAttributedType(attr::TypeNonNull, modifiedType, equivalentType);
 
  case NullabilityKind::Nullable:
    return getAttributedType(attr::TypeNullable, modifiedType, equivalentType);
 
  case NullabilityKind::NullableResult:
    return getAttributedType(attr::TypeNullableResult, modifiedType,
                             equivalentType);
 
  case NullabilityKind::Unspecified:
    return getAttributedType(attr::TypeNullUnspecified, modifiedType,
                             equivalentType);
  }
 
  llvm_unreachable("Unknown nullability kind");
}
 
QualType ASTContext::getBTFTagAttributedType(const BTFTypeTagAttr *BTFAttr,
                                             QualType Wrapped) const {
  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, alignof(BTFTagAttributedType))
      BTFTagAttributedType(Canon, Wrapped, BTFAttr);
 
  Types.push_back(Ty);
  BTFTagAttributedTypes.InsertNode(Ty, InsertPos);
 
  return QualType(Ty, 0);
}
 
QualType ASTContext::getHLSLAttributedResourceType(
    QualType Wrapped, QualType Contained,
    const HLSLAttributedResourceType::Attributes &Attrs) {
 
  llvm::FoldingSetNodeID ID;
  HLSLAttributedResourceType::Profile(ID, Wrapped, Contained, Attrs);
 
  void *InsertPos = nullptr;
  HLSLAttributedResourceType *Ty =
      HLSLAttributedResourceTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (Ty)
    return QualType(Ty, 0);
 
  Ty = new (*this, alignof(HLSLAttributedResourceType))
      HLSLAttributedResourceType(Wrapped, Contained, Attrs);
 
  Types.push_back(Ty);
  HLSLAttributedResourceTypes.InsertNode(Ty, InsertPos);
 
  return QualType(Ty, 0);
}
 
QualType ASTContext::getHLSLInlineSpirvType(uint32_t Opcode, uint32_t Size,
                                            uint32_t Alignment,
                                            ArrayRef<SpirvOperand> Operands) {
  llvm::FoldingSetNodeID ID;
  HLSLInlineSpirvType::Profile(ID, Opcode, Size, Alignment, Operands);
 
  void *InsertPos = nullptr;
  HLSLInlineSpirvType *Ty =
      HLSLInlineSpirvTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (Ty)
    return QualType(Ty, 0);
 
  void *Mem = Allocate(
      HLSLInlineSpirvType::totalSizeToAlloc<SpirvOperand>(Operands.size()),
      alignof(HLSLInlineSpirvType));
 
  Ty = new (Mem) HLSLInlineSpirvType(Opcode, Size, Alignment, Operands);
 
  Types.push_back(Ty);
  HLSLInlineSpirvTypes.InsertNode(Ty, InsertPos);
 
  return QualType(Ty, 0);
}
 
/// Retrieve a substitution-result type.
QualType ASTContext::getSubstTemplateTypeParmType(QualType Replacement,
                                                  Decl *AssociatedDecl,
                                                  unsigned Index,
                                                  UnsignedOrNone PackIndex,
                                                  bool Final) const {
  llvm::FoldingSetNodeID ID;
  SubstTemplateTypeParmType::Profile(ID, Replacement, AssociatedDecl, Index,
                                     PackIndex, Final);
  void *InsertPos = nullptr;
  SubstTemplateTypeParmType *SubstParm =
      SubstTemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);
 
  if (!SubstParm) {
    void *Mem = Allocate(SubstTemplateTypeParmType::totalSizeToAlloc<QualType>(
                             !Replacement.isCanonical()),
                         alignof(SubstTemplateTypeParmType));
    SubstParm = new (Mem) SubstTemplateTypeParmType(Replacement, AssociatedDecl,
                                                    Index, PackIndex, Final);
    Types.push_back(SubstParm);
    SubstTemplateTypeParmTypes.InsertNode(SubstParm, InsertPos);
  }
 
  return QualType(SubstParm, 0);
}
 
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, alignof(SubstTemplateTypeParmPackType))
      SubstTemplateTypeParmPackType(Canon, AssociatedDecl, Index, Final,
                                    ArgPack);
  Types.push_back(SubstParm);
  SubstTemplateTypeParmPackTypes.InsertNode(SubstParm, InsertPos);
  return QualType(SubstParm, 0);
}
 
QualType
ASTContext::getSubstBuiltinTemplatePack(const TemplateArgument &ArgPack) {
  assert(llvm::all_of(ArgPack.pack_elements(),
                      [](const auto &P) {
                        return P.getKind() == TemplateArgument::Type;
                      }) &&
         "Pack contains a non-type");
 
  llvm::FoldingSetNodeID ID;
  SubstBuiltinTemplatePackType::Profile(ID, ArgPack);
 
  void *InsertPos = nullptr;
  if (auto *T =
          SubstBuiltinTemplatePackTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(T, 0);
 
  QualType Canon;
  TemplateArgument CanonArgPack = getCanonicalTemplateArgument(ArgPack);
  if (!CanonArgPack.structurallyEquals(ArgPack)) {
    Canon = getSubstBuiltinTemplatePack(CanonArgPack);
    // Refresh InsertPos, in case the recursive call above caused rehashing,
    // which would invalidate the bucket pointer.
    [[maybe_unused]] const auto *Nothing =
        SubstBuiltinTemplatePackTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!Nothing);
  }
 
  auto *PackType = new (*this, alignof(SubstBuiltinTemplatePackType))
      SubstBuiltinTemplatePackType(Canon, ArgPack);
  Types.push_back(PackType);
  SubstBuiltinTemplatePackTypes.InsertNode(PackType, InsertPos);
  return QualType(PackType, 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, alignof(TemplateTypeParmType))
        TemplateTypeParmType(Depth, Index, ParameterPack, TTPDecl, Canon);
 
    TemplateTypeParmType *TypeCheck
      = TemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!TypeCheck && "Template type parameter canonical type broken");
    (void)TypeCheck;
  } else
    TypeParm = new (*this, alignof(TemplateTypeParmType)) TemplateTypeParmType(
        Depth, Index, ParameterPack, /*TTPDecl=*/nullptr, /*Canon=*/QualType());
 
  Types.push_back(TypeParm);
  TemplateTypeParmTypes.InsertNode(TypeParm, InsertPos);
 
  return QualType(TypeParm, 0);
}
 
static ElaboratedTypeKeyword
getCanonicalElaboratedTypeKeyword(ElaboratedTypeKeyword Keyword) {
  switch (Keyword) {
  // These are just themselves.
  case ElaboratedTypeKeyword::None:
  case ElaboratedTypeKeyword::Struct:
  case ElaboratedTypeKeyword::Union:
  case ElaboratedTypeKeyword::Enum:
  case ElaboratedTypeKeyword::Interface:
    return Keyword;
 
  // These are equivalent.
  case ElaboratedTypeKeyword::Typename:
    return ElaboratedTypeKeyword::None;
 
  // These are functionally equivalent, so relying on their equivalence is
  // IFNDR. By making them equivalent, we disallow overloading, which at least
  // can produce a diagnostic.
  case ElaboratedTypeKeyword::Class:
    return ElaboratedTypeKeyword::Struct;
  }
  llvm_unreachable("unexpected keyword kind");
}
 
TypeSourceInfo *ASTContext::getTemplateSpecializationTypeInfo(
    ElaboratedTypeKeyword Keyword, SourceLocation ElaboratedKeywordLoc,
    NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKeywordLoc,
    TemplateName Name, SourceLocation NameLoc,
    const TemplateArgumentListInfo &SpecifiedArgs,
    ArrayRef<TemplateArgument> CanonicalArgs, QualType Underlying) const {
  QualType TST = getTemplateSpecializationType(
      Keyword, Name, SpecifiedArgs.arguments(), CanonicalArgs, Underlying);
 
  TypeSourceInfo *TSI = CreateTypeSourceInfo(TST);
  TSI->getTypeLoc().castAs<TemplateSpecializationTypeLoc>().set(
      ElaboratedKeywordLoc, QualifierLoc, TemplateKeywordLoc, NameLoc,
      SpecifiedArgs);
  return TSI;
}
 
QualType ASTContext::getTemplateSpecializationType(
    ElaboratedTypeKeyword Keyword, TemplateName Template,
    ArrayRef<TemplateArgumentLoc> SpecifiedArgs,
    ArrayRef<TemplateArgument> CanonicalArgs, QualType Underlying) const {
  SmallVector<TemplateArgument, 4> SpecifiedArgVec;
  SpecifiedArgVec.reserve(SpecifiedArgs.size());
  for (const TemplateArgumentLoc &Arg : SpecifiedArgs)
    SpecifiedArgVec.push_back(Arg.getArgument());
 
  return getTemplateSpecializationType(Keyword, Template, SpecifiedArgVec,
                                       CanonicalArgs, Underlying);
}
 
[[maybe_unused]] static bool
hasAnyPackExpansions(ArrayRef<TemplateArgument> Args) {
  for (const TemplateArgument &Arg : Args)
    if (Arg.isPackExpansion())
      return true;
  return false;
}
 
QualType ASTContext::getCanonicalTemplateSpecializationType(
    ElaboratedTypeKeyword Keyword, TemplateName Template,
    ArrayRef<TemplateArgument> Args) const {
  assert(Template ==
         getCanonicalTemplateName(Template, /*IgnoreDeduced=*/true));
  assert((Keyword == ElaboratedTypeKeyword::None ||
          Template.getAsDependentTemplateName()));
#ifndef NDEBUG
  for (const auto &Arg : Args)
    assert(Arg.structurallyEquals(getCanonicalTemplateArgument(Arg)));
#endif
 
  llvm::FoldingSetNodeID ID;
  TemplateSpecializationType::Profile(ID, Keyword, Template, Args, QualType(),
                                      *this);
  void *InsertPos = nullptr;
  if (auto *T = TemplateSpecializationTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(T, 0);
 
  void *Mem = Allocate(sizeof(TemplateSpecializationType) +
                           sizeof(TemplateArgument) * Args.size(),
                       alignof(TemplateSpecializationType));
  auto *Spec =
      new (Mem) TemplateSpecializationType(Keyword, Template,
                                           /*IsAlias=*/false, Args, QualType());
  assert(Spec->isDependentType() &&
         "canonical template specialization must be dependent");
  Types.push_back(Spec);
  TemplateSpecializationTypes.InsertNode(Spec, InsertPos);
  return QualType(Spec, 0);
}
 
QualType ASTContext::getTemplateSpecializationType(
    ElaboratedTypeKeyword Keyword, TemplateName Template,
    ArrayRef<TemplateArgument> SpecifiedArgs,
    ArrayRef<TemplateArgument> CanonicalArgs, QualType Underlying) const {
  const auto *TD = Template.getAsTemplateDecl(/*IgnoreDeduced=*/true);
  bool IsTypeAlias = TD && TD->isTypeAlias();
  if (Underlying.isNull()) {
    TemplateName CanonTemplate =
        getCanonicalTemplateName(Template, /*IgnoreDeduced=*/true);
    ElaboratedTypeKeyword CanonKeyword =
        CanonTemplate.getAsDependentTemplateName()
            ? getCanonicalElaboratedTypeKeyword(Keyword)
            : ElaboratedTypeKeyword::None;
    bool NonCanonical = Template != CanonTemplate || Keyword != CanonKeyword;
    SmallVector<TemplateArgument, 4> CanonArgsVec;
    if (CanonicalArgs.empty()) {
      CanonArgsVec = SmallVector<TemplateArgument, 4>(SpecifiedArgs);
      NonCanonical |= canonicalizeTemplateArguments(CanonArgsVec);
      CanonicalArgs = CanonArgsVec;
    } else {
      NonCanonical |= !llvm::equal(
          SpecifiedArgs, CanonicalArgs,
          [](const TemplateArgument &A, const TemplateArgument &B) {
            return A.structurallyEquals(B);
          });
    }
 
    // We can get here with an alias template when the specialization
    // contains a pack expansion that does not match up with a parameter
    // pack, or a builtin template which cannot be resolved due to dependency.
    assert((!isa_and_nonnull<TypeAliasTemplateDecl>(TD) ||
            hasAnyPackExpansions(CanonicalArgs)) &&
           "Caller must compute aliased type");
    IsTypeAlias = false;
 
    Underlying = getCanonicalTemplateSpecializationType(
        CanonKeyword, CanonTemplate, CanonicalArgs);
    if (!NonCanonical)
      return Underlying;
  }
  void *Mem = Allocate(sizeof(TemplateSpecializationType) +
                           sizeof(TemplateArgument) * SpecifiedArgs.size() +
                           (IsTypeAlias ? sizeof(QualType) : 0),
                       alignof(TemplateSpecializationType));
  auto *Spec = new (Mem) TemplateSpecializationType(
      Keyword, Template, IsTypeAlias, SpecifiedArgs, Underlying);
  Types.push_back(Spec);
  return QualType(Spec, 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, alignof(ParenType)) 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, alignof(MacroQualifiedType))
      MacroQualifiedType(UnderlyingTy, Canon, MacroII);
  Types.push_back(newType);
  return QualType(newType, 0);
}
 
QualType ASTContext::getDependentNameType(ElaboratedTypeKeyword Keyword,
                                          NestedNameSpecifier NNS,
                                          const IdentifierInfo *Name) const {
  llvm::FoldingSetNodeID ID;
  DependentNameType::Profile(ID, Keyword, NNS, Name);
 
  void *InsertPos = nullptr;
  if (DependentNameType *T =
          DependentNameTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(T, 0);
 
  ElaboratedTypeKeyword CanonKeyword =
      getCanonicalElaboratedTypeKeyword(Keyword);
  NestedNameSpecifier CanonNNS = NNS.getCanonical();
 
  QualType Canon;
  if (CanonKeyword != Keyword || CanonNNS != NNS) {
    Canon = getDependentNameType(CanonKeyword, CanonNNS, Name);
    [[maybe_unused]] DependentNameType *T =
        DependentNameTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!T && "broken canonicalization");
    assert(Canon.isCanonical());
  }
 
  DependentNameType *T = new (*this, alignof(DependentNameType))
      DependentNameType(Keyword, NNS, Name, Canon);
  Types.push_back(T);
  DependentNameTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}
 
TemplateArgument ASTContext::getInjectedTemplateArg(NamedDecl *Param) const {
  TemplateArgument Arg;
  if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
    QualType ArgType = getTypeDeclType(TTP);
    if (TTP->isParameterPack())
      ArgType = getPackExpansionType(ArgType, std::nullopt);
 
    Arg = TemplateArgument(ArgType);
  } else if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
    QualType T =
        NTTP->getType().getNonPackExpansionType().getNonLValueExprType(*this);
    // For class NTTPs, ensure we include the 'const' so the type matches that
    // of a real template argument.
    // FIXME: It would be more faithful to model this as something like an
    // lvalue-to-rvalue conversion applied to a const-qualified lvalue.
    ExprValueKind VK;
    if (T->isRecordType()) {
      // C++ [temp.param]p8: An id-expression naming a non-type
      // template-parameter of class type T denotes a static storage duration
      // object of type const T.
      T.addConst();
      VK = VK_LValue;
    } else {
      VK = Expr::getValueKindForType(NTTP->getType());
    }
    Expr *E = new (*this)
        DeclRefExpr(*this, NTTP, /*RefersToEnclosingVariableOrCapture=*/false,
                    T, VK, NTTP->getLocation());
 
    if (NTTP->isParameterPack())
      E = new (*this) PackExpansionExpr(E, NTTP->getLocation(), std::nullopt);
    Arg = TemplateArgument(E, /*IsCanonical=*/false);
  } else {
    auto *TTP = cast<TemplateTemplateParmDecl>(Param);
    TemplateName Name = getQualifiedTemplateName(
        /*Qualifier=*/std::nullopt, /*TemplateKeyword=*/false,
        TemplateName(TTP));
    if (TTP->isParameterPack())
      Arg = TemplateArgument(Name, /*NumExpansions=*/std::nullopt);
    else
      Arg = TemplateArgument(Name);
  }
 
  if (Param->isTemplateParameterPack())
    Arg =
        TemplateArgument::CreatePackCopy(const_cast<ASTContext &>(*this), Arg);
 
  return Arg;
}
 
QualType ASTContext::getPackExpansionType(QualType Pattern,
                                          UnsignedOrNone NumExpansions,
                                          bool ExpectPackInType) const {
  assert((!ExpectPackInType || Pattern->containsUnexpandedParameterPack()) &&
         "Pack expansions must expand one or more parameter packs");
 
  llvm::FoldingSetNodeID ID;
  PackExpansionType::Profile(ID, Pattern, NumExpansions);
 
  void *InsertPos = nullptr;
  PackExpansionType *T = PackExpansionTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);
 
  QualType Canon;
  if (!Pattern.isCanonical()) {
    Canon = getPackExpansionType(getCanonicalType(Pattern), NumExpansions,
                                 /*ExpectPackInType=*/false);
 
    // Find the insert position again, in case we inserted an element into
    // PackExpansionTypes and invalidated our insert position.
    PackExpansionTypes.FindNodeOrInsertPos(ID, InsertPos);
  }
 
  T = new (*this, alignof(PackExpansionType))
      PackExpansionType(Pattern, Canon, NumExpansions);
  Types.push_back(T);
  PackExpansionTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}
 
/// CmpProtocolNames - Comparison predicate for sorting protocols
/// alphabetically.
static int CmpProtocolNames(ObjCProtocolDecl *const *LHS,
                            ObjCProtocolDecl *const *RHS) {
  return DeclarationName::compare((*LHS)->getDeclName(), (*RHS)->getDeclName());
}
 
static bool areSortedAndUniqued(ArrayRef<ObjCProtocolDecl *> Protocols) {
  if (Protocols.empty()) return true;
 
  if (Protocols[0]->getCanonicalDecl() != Protocols[0])
    return false;
 
  for (unsigned i = 1; i != Protocols.size(); ++i)
    if (CmpProtocolNames(&Protocols[i - 1], &Protocols[i]) >= 0 ||
        Protocols[i]->getCanonicalDecl() != Protocols[i])
      return false;
  return true;
}
 
static void
SortAndUniqueProtocols(SmallVectorImpl<ObjCProtocolDecl *> &Protocols) {
  // Sort protocols, keyed by name.
  llvm::array_pod_sort(Protocols.begin(), Protocols.end(), CmpProtocolNames);
 
  // Canonicalize.
  for (ObjCProtocolDecl *&P : Protocols)
    P = P->getCanonicalDecl();
 
  // Remove duplicates.
  auto ProtocolsEnd = llvm::unique(Protocols);
  Protocols.erase(ProtocolsEnd, Protocols.end());
}
 
QualType ASTContext::getObjCObjectType(QualType BaseType,
                                       ObjCProtocolDecl * const *Protocols,
                                       unsigned NumProtocols) const {
  return getObjCObjectType(BaseType, {}, ArrayRef(Protocols, NumProtocols),
                           /*isKindOf=*/false);
}
 
QualType ASTContext::getObjCObjectType(
           QualType baseType,
           ArrayRef<QualType> typeArgs,
           ArrayRef<ObjCProtocolDecl *> protocols,
           bool isKindOf) const {
  // If the base type is an interface and there aren't any protocols or
  // type arguments to add, then the interface type will do just fine.
  if (typeArgs.empty() && protocols.empty() && !isKindOf &&
      isa<ObjCInterfaceType>(baseType))
    return baseType;
 
  // Look in the folding set for an existing type.
  llvm::FoldingSetNodeID ID;
  ObjCObjectTypeImpl::Profile(ID, baseType, typeArgs, protocols, isKindOf);
  void *InsertPos = nullptr;
  if (ObjCObjectType *QT = ObjCObjectTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(QT, 0);
 
  // Determine the type arguments to be used for canonicalization,
  // which may be explicitly specified here or written on the base
  // type.
  ArrayRef<QualType> effectiveTypeArgs = typeArgs;
  if (effectiveTypeArgs.empty()) {
    if (const auto *baseObject = baseType->getAs<ObjCObjectType>())
      effectiveTypeArgs = baseObject->getTypeArgs();
  }
 
  // Build the canonical type, which has the canonical base type and a
  // sorted-and-uniqued list of protocols and the type arguments
  // canonicalized.
  QualType canonical;
  bool typeArgsAreCanonical = llvm::all_of(
      effectiveTypeArgs, [&](QualType type) { return type.isCanonical(); });
  bool protocolsSorted = areSortedAndUniqued(protocols);
  if (!typeArgsAreCanonical || !protocolsSorted || !baseType.isCanonical()) {
    // Determine the canonical type arguments.
    ArrayRef<QualType> canonTypeArgs;
    SmallVector<QualType, 4> canonTypeArgsVec;
    if (!typeArgsAreCanonical) {
      canonTypeArgsVec.reserve(effectiveTypeArgs.size());
      for (auto typeArg : effectiveTypeArgs)
        canonTypeArgsVec.push_back(getCanonicalType(typeArg));
      canonTypeArgs = canonTypeArgsVec;
    } else {
      canonTypeArgs = effectiveTypeArgs;
    }
 
    ArrayRef<ObjCProtocolDecl *> canonProtocols;
    SmallVector<ObjCProtocolDecl*, 8> canonProtocolsVec;
    if (!protocolsSorted) {
      canonProtocolsVec.append(protocols.begin(), protocols.end());
      SortAndUniqueProtocols(canonProtocolsVec);
      canonProtocols = canonProtocolsVec;
    } else {
      canonProtocols = protocols;
    }
 
    canonical = getObjCObjectType(getCanonicalType(baseType), canonTypeArgs,
                                  canonProtocols, isKindOf);
 
    // Regenerate InsertPos.
    ObjCObjectTypes.FindNodeOrInsertPos(ID, InsertPos);
  }
 
  unsigned size = sizeof(ObjCObjectTypeImpl);
  size += typeArgs.size() * sizeof(QualType);
  size += protocols.size() * sizeof(ObjCProtocolDecl *);
  void *mem = Allocate(size, alignof(ObjCObjectTypeImpl));
  auto *T =
    new (mem) ObjCObjectTypeImpl(canonical, baseType, typeArgs, protocols,
                                 isKindOf);
 
  Types.push_back(T);
  ObjCObjectTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}
 
/// Apply Objective-C protocol qualifiers to the given type.
/// If this is for the canonical type of a type parameter, we can apply
/// protocol qualifiers on the ObjCObjectPointerType.
QualType
ASTContext::applyObjCProtocolQualifiers(QualType type,
                  ArrayRef<ObjCProtocolDecl *> protocols, bool &hasError,
                  bool allowOnPointerType) const {
  hasError = false;
 
  if (const auto *objT = dyn_cast<ObjCTypeParamType>(type.getTypePtr())) {
    return getObjCTypeParamType(objT->getDecl(), protocols);
  }
 
  // Apply protocol qualifiers to ObjCObjectPointerType.
  if (allowOnPointerType) {
    if (const auto *objPtr =
            dyn_cast<ObjCObjectPointerType>(type.getTypePtr())) {
      const ObjCObjectType *objT = objPtr->getObjectType();
      // Merge protocol lists and construct ObjCObjectType.
      SmallVector<ObjCProtocolDecl*, 8> protocolsVec;
      protocolsVec.append(objT->qual_begin(),
                          objT->qual_end());
      protocolsVec.append(protocols.begin(), protocols.end());
      ArrayRef<ObjCProtocolDecl *> protocols = protocolsVec;
      type = getObjCObjectType(
             objT->getBaseType(),
             objT->getTypeArgsAsWritten(),
             protocols,
             objT->isKindOfTypeAsWritten());
      return getObjCObjectPointerType(type);
    }
  }
 
  // Apply protocol qualifiers to ObjCObjectType.
  if (const auto *objT = dyn_cast<ObjCObjectType>(type.getTypePtr())){
    // FIXME: Check for protocols to which the class type is already
    // known to conform.
 
    return getObjCObjectType(objT->getBaseType(),
                             objT->getTypeArgsAsWritten(),
                             protocols,
                             objT->isKindOfTypeAsWritten());
  }
 
  // If the canonical type is ObjCObjectType, ...
  if (type->isObjCObjectType()) {
    // Silently overwrite any existing protocol qualifiers.
    // TODO: determine whether that's the right thing to do.
 
    // FIXME: Check for protocols to which the class type is already
    // known to conform.
    return getObjCObjectType(type, {}, protocols, false);
  }
 
  // id<protocol-list>
  if (type->isObjCIdType()) {
    const auto *objPtr = type->castAs<ObjCObjectPointerType>();
    type = getObjCObjectType(ObjCBuiltinIdTy, {}, protocols,
                                 objPtr->isKindOfType());
    return getObjCObjectPointerType(type);
  }
 
  // Class<protocol-list>
  if (type->isObjCClassType()) {
    const auto *objPtr = type->castAs<ObjCObjectPointerType>();
    type = getObjCObjectType(ObjCBuiltinClassTy, {}, protocols,
                                 objPtr->isKindOfType());
    return getObjCObjectPointerType(type);
  }
 
  hasError = true;
  return type;
}
 
QualType
ASTContext::getObjCTypeParamType(const ObjCTypeParamDecl *Decl,
                                 ArrayRef<ObjCProtocolDecl *> protocols) const {
  // Look in the folding set for an existing type.
  llvm::FoldingSetNodeID ID;
  ObjCTypeParamType::Profile(ID, Decl, Decl->getUnderlyingType(), protocols);
  void *InsertPos = nullptr;
  if (ObjCTypeParamType *TypeParam =
      ObjCTypeParamTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(TypeParam, 0);
 
  // We canonicalize to the underlying type.
  QualType Canonical = getCanonicalType(Decl->getUnderlyingType());
  if (!protocols.empty()) {
    // Apply the protocol qualifers.
    bool hasError;
    Canonical = getCanonicalType(applyObjCProtocolQualifiers(
        Canonical, protocols, hasError, true /*allowOnPointerType*/));
    assert(!hasError && "Error when apply protocol qualifier to bound type");
  }
 
  unsigned size = sizeof(ObjCTypeParamType);
  size += protocols.size() * sizeof(ObjCProtocolDecl *);
  void *mem = Allocate(size, alignof(ObjCTypeParamType));
  auto *newType = new (mem) ObjCTypeParamType(Decl, Canonical, protocols);
 
  Types.push_back(newType);
  ObjCTypeParamTypes.InsertNode(newType, InsertPos);
  return QualType(newType, 0);
}
 
void ASTContext::adjustObjCTypeParamBoundType(const ObjCTypeParamDecl *Orig,
                                              ObjCTypeParamDecl *New) const {
  New->setTypeSourceInfo(getTrivialTypeSourceInfo(Orig->getUnderlyingType()));
  // Update TypeForDecl after updating TypeSourceInfo.
  auto *NewTypeParamTy = cast<ObjCTypeParamType>(New->TypeForDecl);
  SmallVector<ObjCProtocolDecl *, 8> protocols;
  protocols.append(NewTypeParamTy->qual_begin(), NewTypeParamTy->qual_end());
  QualType UpdatedTy = getObjCTypeParamType(New, protocols);
  New->TypeForDecl = UpdatedTy.getTypePtr();
}
 
/// ObjCObjectAdoptsQTypeProtocols - Checks that protocols in IC's
/// protocol list adopt all protocols in QT's qualified-id protocol
/// list.
bool ASTContext::ObjCObjectAdoptsQTypeProtocols(QualType QT,
                                                ObjCInterfaceDecl *IC) {
  if (!QT->isObjCQualifiedIdType())
    return false;
 
  if (const auto *OPT = QT->getAs<ObjCObjectPointerType>()) {
    // If both the right and left sides have qualifiers.
    for (auto *Proto : OPT->quals()) {
      if (!IC->ClassImplementsProtocol(Proto, false))
        return false;
    }
    return true;
  }
  return false;
}
 
/// QIdProtocolsAdoptObjCObjectProtocols - Checks that protocols in
/// QT's qualified-id protocol list adopt all protocols in IDecl's list
/// of protocols.
bool ASTContext::QIdProtocolsAdoptObjCObjectProtocols(QualType QT,
                                                ObjCInterfaceDecl *IDecl) {
  if (!QT->isObjCQualifiedIdType())
    return false;
  const auto *OPT = QT->getAs<ObjCObjectPointerType>();
  if (!OPT)
    return false;
  if (!IDecl->hasDefinition())
    return false;
  llvm::SmallPtrSet<ObjCProtocolDecl *, 8> InheritedProtocols;
  CollectInheritedProtocols(IDecl, InheritedProtocols);
  if (InheritedProtocols.empty())
    return false;
  // Check that if every protocol in list of id<plist> conforms to a protocol
  // of IDecl's, then bridge casting is ok.
  bool Conforms = false;
  for (auto *Proto : OPT->quals()) {
    Conforms = false;
    for (auto *PI : InheritedProtocols) {
      if (ProtocolCompatibleWithProtocol(Proto, PI)) {
        Conforms = true;
        break;
      }
    }
    if (!Conforms)
      break;
  }
  if (Conforms)
    return true;
 
  for (auto *PI : InheritedProtocols) {
    // If both the right and left sides have qualifiers.
    bool Adopts = false;
    for (auto *Proto : OPT->quals()) {
      // return 'true' if 'PI' is in the inheritance hierarchy of Proto
      if ((Adopts = ProtocolCompatibleWithProtocol(PI, Proto)))
        break;
    }
    if (!Adopts)
      return false;
  }
  return true;
}
 
/// getObjCObjectPointerType - Return a ObjCObjectPointerType type for
/// the given object type.
QualType ASTContext::getObjCObjectPointerType(QualType ObjectT) const {
  llvm::FoldingSetNodeID ID;
  ObjCObjectPointerType::Profile(ID, ObjectT);
 
  void *InsertPos = nullptr;
  if (ObjCObjectPointerType *QT =
              ObjCObjectPointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(QT, 0);
 
  // Find the canonical object type.
  QualType Canonical;
  if (!ObjectT.isCanonical()) {
    Canonical = getObjCObjectPointerType(getCanonicalType(ObjectT));
 
    // Regenerate InsertPos.
    ObjCObjectPointerTypes.FindNodeOrInsertPos(ID, InsertPos);
  }
 
  // No match.
  void *Mem =
      Allocate(sizeof(ObjCObjectPointerType), alignof(ObjCObjectPointerType));
  auto *QType =
    new (Mem) ObjCObjectPointerType(Canonical, ObjectT);
 
  Types.push_back(QType);
  ObjCObjectPointerTypes.InsertNode(QType, InsertPos);
  return QualType(QType, 0);
}
 
/// getObjCInterfaceType - Return the unique reference to the type for the
/// specified ObjC interface decl. The list of protocols is optional.
QualType ASTContext::getObjCInterfaceType(const ObjCInterfaceDecl *Decl,
                                          ObjCInterfaceDecl *PrevDecl) const {
  if (Decl->TypeForDecl)
    return QualType(Decl->TypeForDecl, 0);
 
  if (PrevDecl) {
    assert(PrevDecl->TypeForDecl && "previous decl has no TypeForDecl");
    Decl->TypeForDecl = PrevDecl->TypeForDecl;
    return QualType(PrevDecl->TypeForDecl, 0);
  }
 
  // Prefer the definition, if there is one.
  if (const ObjCInterfaceDecl *Def = Decl->getDefinition())
    Decl = Def;
 
  void *Mem = Allocate(sizeof(ObjCInterfaceType), alignof(ObjCInterfaceType));
  auto *T = new (Mem) ObjCInterfaceType(Decl);
  Decl->TypeForDecl = T;
  Types.push_back(T);
  return QualType(T, 0);
}
 
/// getTypeOfExprType - Unlike many "get<Type>" functions, we can't unique
/// TypeOfExprType AST's (since expression's are never shared). For example,
/// multiple declarations that refer to "typeof(x)" all contain different
/// DeclRefExpr's. This doesn't effect the type checker, since it operates
/// on canonical type's (which are always unique).
QualType ASTContext::getTypeOfExprType(Expr *tofExpr, TypeOfKind Kind) const {
  TypeOfExprType *toe;
  if (tofExpr->isTypeDependent()) {
    llvm::FoldingSetNodeID ID;
    DependentTypeOfExprType::Profile(ID, *this, tofExpr,
                                     Kind == TypeOfKind::Unqualified);
 
    void *InsertPos = nullptr;
    DependentTypeOfExprType *Canon =
        DependentTypeOfExprTypes.FindNodeOrInsertPos(ID, InsertPos);
    if (Canon) {
      // We already have a "canonical" version of an identical, dependent
      // typeof(expr) type. Use that as our canonical type.
      toe = new (*this, alignof(TypeOfExprType)) TypeOfExprType(
          *this, tofExpr, Kind, QualType((TypeOfExprType *)Canon, 0));
    } else {
      // Build a new, canonical typeof(expr) type.
      Canon = new (*this, alignof(DependentTypeOfExprType))
          DependentTypeOfExprType(*this, tofExpr, Kind);
      DependentTypeOfExprTypes.InsertNode(Canon, InsertPos);
      toe = Canon;
    }
  } else {
    QualType Canonical = getCanonicalType(tofExpr->getType());
    toe = new (*this, alignof(TypeOfExprType))
        TypeOfExprType(*this, tofExpr, Kind, Canonical);
  }
  Types.push_back(toe);
  return QualType(toe, 0);
}
 
/// getTypeOfType -  Unlike many "get<Type>" functions, we don't unique
/// TypeOfType nodes. The only motivation to unique these nodes would be
/// memory savings. Since typeof(t) is fairly uncommon, space shouldn't be
/// an issue. This doesn't affect the type checker, since it operates
/// on canonical types (which are always unique).
QualType ASTContext::getTypeOfType(QualType tofType, TypeOfKind Kind) const {
  QualType Canonical = getCanonicalType(tofType);
  auto *tot = new (*this, alignof(TypeOfType))
      TypeOfType(*this, tofType, Canonical, Kind);
  Types.push_back(tot);
  return QualType(tot, 0);
}
 
/// getReferenceQualifiedType - Given an expr, will return the type for
/// that expression, as in [dcl.type.simple]p4 but without taking id-expressions
/// and class member access into account.
QualType ASTContext::getReferenceQualifiedType(const Expr *E) const {
  // C++11 [dcl.type.simple]p4:
  //   [...]
  QualType T = E->getType();
  switch (E->getValueKind()) {
  //     - otherwise, if e is an xvalue, decltype(e) is T&&, where T is the
  //       type of e;
  case VK_XValue:
    return getRValueReferenceType(T);
  //     - otherwise, if e is an lvalue, decltype(e) is T&, where T is the
  //       type of e;
  case VK_LValue:
    return getLValueReferenceType(T);
  //  - otherwise, decltype(e) is the type of e.
  case VK_PRValue:
    return T;
  }
  llvm_unreachable("Unknown value kind");
}
 
/// Unlike many "get<Type>" functions, we don't unique DecltypeType
/// nodes. This would never be helpful, since each such type has its own
/// expression, and would not give a significant memory saving, since there
/// is an Expr tree under each such type.
QualType ASTContext::getDecltypeType(Expr *E, QualType UnderlyingType) const {
  // C++11 [temp.type]p2:
  //   If an expression e involves a template parameter, decltype(e) denotes a
  //   unique dependent type. Two such decltype-specifiers refer to the same
  //   type only if their expressions are equivalent (14.5.6.1).
  QualType CanonType;
  if (!E->isInstantiationDependent()) {
    CanonType = getCanonicalType(UnderlyingType);
  } else if (!UnderlyingType.isNull()) {
    CanonType = getDecltypeType(E, QualType());
  } else {
    llvm::FoldingSetNodeID ID;
    DependentDecltypeType::Profile(ID, *this, E);
 
    void *InsertPos = nullptr;
    if (DependentDecltypeType *Canon =
            DependentDecltypeTypes.FindNodeOrInsertPos(ID, InsertPos))
      return QualType(Canon, 0);
 
    // Build a new, canonical decltype(expr) type.
    auto *DT =
        new (*this, alignof(DependentDecltypeType)) DependentDecltypeType(E);
    DependentDecltypeTypes.InsertNode(DT, InsertPos);
    Types.push_back(DT);
    return QualType(DT, 0);
  }
  auto *DT = new (*this, alignof(DecltypeType))
      DecltypeType(E, UnderlyingType, CanonType);
  Types.push_back(DT);
  return QualType(DT, 0);
}
 
QualType ASTContext::getPackIndexingType(QualType Pattern, Expr *IndexExpr,
                                         bool FullySubstituted,
                                         ArrayRef<QualType> Expansions,
                                         UnsignedOrNone Index) const {
  QualType Canonical;
  if (FullySubstituted && Index) {
    Canonical = getCanonicalType(Expansions[*Index]);
  } else {
    llvm::FoldingSetNodeID ID;
    PackIndexingType::Profile(ID, *this, Pattern.getCanonicalType(), IndexExpr,
                              FullySubstituted, Expansions);
    void *InsertPos = nullptr;
    PackIndexingType *Canon =
        DependentPackIndexingTypes.FindNodeOrInsertPos(ID, InsertPos);
    if (!Canon) {
      void *Mem = Allocate(
          PackIndexingType::totalSizeToAlloc<QualType>(Expansions.size()),
          TypeAlignment);
      Canon =
          new (Mem) PackIndexingType(QualType(), Pattern.getCanonicalType(),
                                     IndexExpr, FullySubstituted, Expansions);
      DependentPackIndexingTypes.InsertNode(Canon, InsertPos);
    }
    Canonical = QualType(Canon, 0);
  }
 
  void *Mem =
      Allocate(PackIndexingType::totalSizeToAlloc<QualType>(Expansions.size()),
               TypeAlignment);
  auto *T = new (Mem) PackIndexingType(Canonical, Pattern, IndexExpr,
                                       FullySubstituted, Expansions);
  Types.push_back(T);
  return QualType(T, 0);
}
 
/// getUnaryTransformationType - We don't unique these, since the memory
/// savings are minimal and these are rare.
QualType
ASTContext::getUnaryTransformType(QualType BaseType, QualType UnderlyingType,
                                  UnaryTransformType::UTTKind Kind) const {
 
  llvm::FoldingSetNodeID ID;
  UnaryTransformType::Profile(ID, BaseType, UnderlyingType, Kind);
 
  void *InsertPos = nullptr;
  if (UnaryTransformType *UT =
          UnaryTransformTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(UT, 0);
 
  QualType CanonType;
  if (!BaseType->isDependentType()) {
    CanonType = UnderlyingType.getCanonicalType();
  } else {
    assert(UnderlyingType.isNull() || BaseType == UnderlyingType);
    UnderlyingType = QualType();
    if (QualType CanonBase = BaseType.getCanonicalType();
        BaseType != CanonBase) {
      CanonType = getUnaryTransformType(CanonBase, QualType(), Kind);
      assert(CanonType.isCanonical());
 
      // Find the insertion position again.
      [[maybe_unused]] UnaryTransformType *UT =
          UnaryTransformTypes.FindNodeOrInsertPos(ID, InsertPos);
      assert(!UT && "broken canonicalization");
    }
  }
 
  auto *UT = new (*this, alignof(UnaryTransformType))
      UnaryTransformType(BaseType, UnderlyingType, Kind, CanonType);
  UnaryTransformTypes.InsertNode(UT, InsertPos);
  Types.push_back(UT);
  return QualType(UT, 0);
}
 
QualType ASTContext::getAutoTypeInternal(
    QualType DeducedType, AutoTypeKeyword Keyword, bool IsDependent,
    bool IsPack, TemplateDecl *TypeConstraintConcept,
    ArrayRef<TemplateArgument> TypeConstraintArgs, bool IsCanon) const {
  if (DeducedType.isNull() && Keyword == AutoTypeKeyword::Auto &&
      !TypeConstraintConcept && !IsDependent)
    return getAutoDeductType();
 
  // Look in the folding set for an existing type.
  llvm::FoldingSetNodeID ID;
  bool IsDeducedDependent =
      isa_and_nonnull<TemplateTemplateParmDecl>(TypeConstraintConcept) ||
      (!DeducedType.isNull() && DeducedType->isDependentType());
  AutoType::Profile(ID, *this, DeducedType, Keyword,
                    IsDependent || IsDeducedDependent, TypeConstraintConcept,
                    TypeConstraintArgs);
  if (auto const AT_iter = AutoTypes.find(ID); AT_iter != AutoTypes.end())
    return QualType(AT_iter->getSecond(), 0);
 
  QualType Canon;
  if (!IsCanon) {
    if (!DeducedType.isNull()) {
      Canon = DeducedType.getCanonicalType();
    } else if (TypeConstraintConcept) {
      bool AnyNonCanonArgs = false;
      auto *CanonicalConcept =
          cast<TemplateDecl>(TypeConstraintConcept->getCanonicalDecl());
      auto CanonicalConceptArgs = ::getCanonicalTemplateArguments(
          *this, TypeConstraintArgs, AnyNonCanonArgs);
      if (CanonicalConcept != TypeConstraintConcept || AnyNonCanonArgs) {
        Canon = getAutoTypeInternal(QualType(), Keyword, IsDependent, IsPack,
                                    CanonicalConcept, CanonicalConceptArgs,
                                    /*IsCanon=*/true);
      }
    }
  }
 
  void *Mem = Allocate(sizeof(AutoType) +
                           sizeof(TemplateArgument) * TypeConstraintArgs.size(),
                       alignof(AutoType));
  auto *AT = new (Mem) AutoType(
      DeducedType, Keyword,
      (IsDependent ? TypeDependence::DependentInstantiation
                   : TypeDependence::None) |
          (IsPack ? TypeDependence::UnexpandedPack : TypeDependence::None),
      Canon, TypeConstraintConcept, TypeConstraintArgs);
#ifndef NDEBUG
  llvm::FoldingSetNodeID InsertedID;
  AT->Profile(InsertedID, *this);
  assert(InsertedID == ID && "ID does not match");
#endif
  Types.push_back(AT);
  AutoTypes.try_emplace(ID, AT);
  return QualType(AT, 0);
}
 
/// getAutoType - Return the uniqued reference to the 'auto' type which has been
/// deduced to the given type, or to the canonical undeduced 'auto' type, or the
/// canonical deduced-but-dependent 'auto' type.
QualType
ASTContext::getAutoType(QualType DeducedType, AutoTypeKeyword Keyword,
                        bool IsDependent, bool IsPack,
                        TemplateDecl *TypeConstraintConcept,
                        ArrayRef<TemplateArgument> TypeConstraintArgs) const {
  assert((!IsPack || IsDependent) && "only use IsPack for a dependent pack");
  assert((!IsDependent || DeducedType.isNull()) &&
         "A dependent auto should be undeduced");
  return getAutoTypeInternal(DeducedType, Keyword, IsDependent, IsPack,
                             TypeConstraintConcept, TypeConstraintArgs);
}
 
QualType ASTContext::getUnconstrainedType(QualType T) const {
  QualType CanonT = T.getNonPackExpansionType().getCanonicalType();
 
  // Remove a type-constraint from a top-level auto or decltype(auto).
  if (auto *AT = CanonT->getAs<AutoType>()) {
    if (!AT->isConstrained())
      return T;
    return getQualifiedType(getAutoType(QualType(), AT->getKeyword(),
                                        AT->isDependentType(),
                                        AT->containsUnexpandedParameterPack()),
                            T.getQualifiers());
  }
 
  // FIXME: We only support constrained auto at the top level in the type of a
  // non-type template parameter at the moment. Once we lift that restriction,
  // we'll need to recursively build types containing auto here.
  assert(!CanonT->getContainedAutoType() ||
         !CanonT->getContainedAutoType()->isConstrained());
  return T;
}
 
QualType ASTContext::getDeducedTemplateSpecializationTypeInternal(
    ElaboratedTypeKeyword Keyword, TemplateName Template, QualType DeducedType,
    bool IsDependent, QualType Canon) const {
  // Look in the folding set for an existing type.
  void *InsertPos = nullptr;
  llvm::FoldingSetNodeID ID;
  DeducedTemplateSpecializationType::Profile(ID, Keyword, Template, DeducedType,
                                             IsDependent);
  if (DeducedTemplateSpecializationType *DTST =
          DeducedTemplateSpecializationTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(DTST, 0);
 
  auto *DTST = new (*this, alignof(DeducedTemplateSpecializationType))
      DeducedTemplateSpecializationType(Keyword, Template, DeducedType,
                                        IsDependent, Canon);
 
#ifndef NDEBUG
  llvm::FoldingSetNodeID TempID;
  DTST->Profile(TempID);
  assert(ID == TempID && "ID does not match");
#endif
  Types.push_back(DTST);
  DeducedTemplateSpecializationTypes.InsertNode(DTST, InsertPos);
  return QualType(DTST, 0);
}
 
/// Return the uniqued reference to the deduced template specialization type
/// which has been deduced to the given type, or to the canonical undeduced
/// such type, or the canonical deduced-but-dependent such type.
QualType ASTContext::getDeducedTemplateSpecializationType(
    ElaboratedTypeKeyword Keyword, TemplateName Template, QualType DeducedType,
    bool IsDependent) const {
  // FIXME: This could save an extra hash table lookup if it handled all the
  // parameters already being canonical.
  // FIXME: Can this be formed from a DependentTemplateName, such that the
  // keyword should be part of the canonical type?
  QualType Canon =
      DeducedType.isNull()
          ? getDeducedTemplateSpecializationTypeInternal(
                ElaboratedTypeKeyword::None, getCanonicalTemplateName(Template),
                QualType(), IsDependent, QualType())
          : DeducedType.getCanonicalType();
  return getDeducedTemplateSpecializationTypeInternal(
      Keyword, Template, DeducedType, IsDependent, Canon);
}
 
/// getAtomicType - Return the uniqued reference to the atomic type for
/// the given value type.
QualType ASTContext::getAtomicType(QualType T) const {
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  AtomicType::Profile(ID, T);
 
  void *InsertPos = nullptr;
  if (AtomicType *AT = AtomicTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(AT, 0);
 
  // If the atomic value 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 = getAtomicType(getCanonicalType(T));
 
    // Get the new insert position for the node we care about.
    AtomicType *NewIP = AtomicTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  auto *New = new (*this, alignof(AtomicType)) AtomicType(T, Canonical);
  Types.push_back(New);
  AtomicTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}
 
/// getAutoDeductType - Get type pattern for deducing against 'auto'.
QualType ASTContext::getAutoDeductType() const {
  if (AutoDeductTy.isNull())
    AutoDeductTy = QualType(new (*this, alignof(AutoType))
                                AutoType(QualType(), AutoTypeKeyword::Auto,
                                         TypeDependence::None, QualType(),
                                         /*concept*/ nullptr, /*args*/ {}),
                            0);
  return AutoDeductTy;
}
 
/// getAutoRRefDeductType - Get type pattern for deducing against 'auto &&'.
QualType ASTContext::getAutoRRefDeductType() const {
  if (AutoRRefDeductTy.isNull())
    AutoRRefDeductTy = getRValueReferenceType(getAutoDeductType());
  assert(!AutoRRefDeductTy.isNull() && "can't build 'auto &&' pattern");
  return AutoRRefDeductTy;
}
 
/// getSizeType - Return the unique type for "size_t" (C99 7.17), the result
/// of the sizeof operator (C99 6.5.3.4p4). The value is target dependent and
/// needs to agree with the definition in <stddef.h>.
QualType ASTContext::getSizeType() const {
  return getPredefinedSugarType(PredefinedSugarType::Kind::SizeT);
}
 
CanQualType ASTContext::getCanonicalSizeType() const {
  return getFromTargetType(Target->getSizeType());
}
 
/// Return the unique signed counterpart of the integer type
/// corresponding to size_t.
QualType ASTContext::getSignedSizeType() const {
  return getPredefinedSugarType(PredefinedSugarType::Kind::SignedSizeT);
}
 
/// getPointerDiffType - Return the unique type for "ptrdiff_t" (C99 7.17)
/// defined in <stddef.h>. Pointer - pointer requires this (C99 6.5.6p9).
QualType ASTContext::getPointerDiffType() const {
  return getPredefinedSugarType(PredefinedSugarType::Kind::PtrdiffT);
}
 
/// Return the unique unsigned counterpart of "ptrdiff_t"
/// integer type. The standard (C11 7.21.6.1p7) refers to this type
/// in the definition of %tu format specifier.
QualType ASTContext::getUnsignedPointerDiffType() const {
  return getFromTargetType(Target->getUnsignedPtrDiffType(LangAS::Default));
}
 
/// getIntMaxType - Return the unique type for "intmax_t" (C99 7.18.1.5).
CanQualType ASTContext::getIntMaxType() const {
  return getFromTargetType(Target->getIntMaxType());
}
 
/// getUIntMaxType - Return the unique type for "uintmax_t" (C99 7.18.1.5).
CanQualType ASTContext::getUIntMaxType() const {
  return getFromTargetType(Target->getUIntMaxType());
}
 
/// getSignedWCharType - Return the type of "signed wchar_t".
/// Used when in C++, as a GCC extension.
QualType ASTContext::getSignedWCharType() const {
  // FIXME: derive from "Target" ?
  return WCharTy;
}
 
/// getUnsignedWCharType - Return the type of "unsigned wchar_t".
/// Used when in C++, as a GCC extension.
QualType ASTContext::getUnsignedWCharType() const {
  // FIXME: derive from "Target" ?
  return UnsignedIntTy;
}
 
QualType ASTContext::getIntPtrType() const {
  return getFromTargetType(Target->getIntPtrType());
}
 
QualType ASTContext::getUIntPtrType() const {
  return getCorrespondingUnsignedType(getIntPtrType());
}
 
/// Return the unique type for "pid_t" defined in
/// <sys/types.h>. We need this to compute the correct type for vfork().
QualType ASTContext::getProcessIDType() const {
  return getFromTargetType(Target->getProcessIDType());
}
 
//===----------------------------------------------------------------------===//
//                              Type Operators
//===----------------------------------------------------------------------===//
 
CanQualType ASTContext::getCanonicalParamType(QualType T) const {
  // Push qualifiers into arrays, and then discard any remaining
  // qualifiers.
  T = getCanonicalType(T);
  T = getVariableArrayDecayedType(T);
  const Type *Ty = T.getTypePtr();
  QualType Result;
  if (getLangOpts().HLSL && isa<ConstantArrayType>(Ty)) {
    Result = getArrayParameterType(QualType(Ty, 0));
  } else if (isa<ArrayType>(Ty)) {
    Result = getArrayDecayedType(QualType(Ty,0));
  } else if (isa<FunctionType>(Ty)) {
    Result = getPointerType(QualType(Ty, 0));
  } else {
    Result = QualType(Ty, 0);
  }
 
  return CanQualType::CreateUnsafe(Result);
}
 
QualType ASTContext::getUnqualifiedArrayType(QualType type,
                                             Qualifiers &quals) const {
  SplitQualType splitType = type.getSplitUnqualifiedType();
 
  // FIXME: getSplitUnqualifiedType() actually walks all the way to
  // the unqualified desugared type and then drops it on the floor.
  // We then have to strip that sugar back off with
  // getUnqualifiedDesugaredType(), which is silly.
  const auto *AT =
      dyn_cast<ArrayType>(splitType.Ty->getUnqualifiedDesugaredType());
 
  // If we don't have an array, just use the results in splitType.
  if (!AT) {
    quals = splitType.Quals;
    return QualType(splitType.Ty, 0);
  }
 
  // Otherwise, recurse on the array's element type.
  QualType elementType = AT->getElementType();
  QualType unqualElementType = getUnqualifiedArrayType(elementType, quals);
 
  // If that didn't change the element type, AT has no qualifiers, so we
  // can just use the results in splitType.
  if (elementType == unqualElementType) {
    assert(quals.empty()); // from the recursive call
    quals = splitType.Quals;
    return QualType(splitType.Ty, 0);
  }
 
  // Otherwise, add in the qualifiers from the outermost type, then
  // build the type back up.
  quals.addConsistentQualifiers(splitType.Quals);
 
  if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
    return getConstantArrayType(unqualElementType, CAT->getSize(),
                                CAT->getSizeExpr(), CAT->getSizeModifier(), 0);
  }
 
  if (const auto *IAT = dyn_cast<IncompleteArrayType>(AT)) {
    return getIncompleteArrayType(unqualElementType, IAT->getSizeModifier(), 0);
  }
 
  if (const auto *VAT = dyn_cast<VariableArrayType>(AT)) {
    return getVariableArrayType(unqualElementType, VAT->getSizeExpr(),
                                VAT->getSizeModifier(),
                                VAT->getIndexTypeCVRQualifiers());
  }
 
  const auto *DSAT = cast<DependentSizedArrayType>(AT);
  return getDependentSizedArrayType(unqualElementType, DSAT->getSizeExpr(),
                                    DSAT->getSizeModifier(), 0);
}
 
/// Attempt to unwrap two types that may both be array types with the same bound
/// (or both be array types of unknown bound) for the purpose of comparing the
/// cv-decomposition of two types per C++ [conv.qual].
///
/// \param AllowPiMismatch Allow the Pi1 and Pi2 to differ as described in
///        C++20 [conv.qual], if permitted by the current language mode.
void ASTContext::UnwrapSimilarArrayTypes(QualType &T1, QualType &T2,
                                         bool AllowPiMismatch) const {
  while (true) {
    auto *AT1 = getAsArrayType(T1);
    if (!AT1)
      return;
 
    auto *AT2 = getAsArrayType(T2);
    if (!AT2)
      return;
 
    // If we don't have two array types with the same constant bound nor two
    // incomplete array types, we've unwrapped everything we can.
    // C++20 also permits one type to be a constant array type and the other
    // to be an incomplete array type.
    // FIXME: Consider also unwrapping array of unknown bound and VLA.
    if (auto *CAT1 = dyn_cast<ConstantArrayType>(AT1)) {
      auto *CAT2 = dyn_cast<ConstantArrayType>(AT2);
      if (!((CAT2 && CAT1->getSize() == CAT2->getSize()) ||
            (AllowPiMismatch && getLangOpts().CPlusPlus20 &&
             isa<IncompleteArrayType>(AT2))))
        return;
    } else if (isa<IncompleteArrayType>(AT1)) {
      if (!(isa<IncompleteArrayType>(AT2) ||
            (AllowPiMismatch && getLangOpts().CPlusPlus20 &&
             isa<ConstantArrayType>(AT2))))
        return;
    } else {
      return;
    }
 
    T1 = AT1->getElementType();
    T2 = AT2->getElementType();
  }
}
 
/// Attempt to unwrap two types that may be similar (C++ [conv.qual]).
///
/// If T1 and T2 are both pointer types of the same kind, or both array types
/// with the same bound, unwraps layers from T1 and T2 until a pointer type is
/// unwrapped. Top-level qualifiers on T1 and T2 are ignored.
///
/// This function will typically be called in a loop that successively
/// "unwraps" pointer and pointer-to-member types to compare them at each
/// level.
///
/// \param AllowPiMismatch Allow the Pi1 and Pi2 to differ as described in
///        C++20 [conv.qual], if permitted by the current language mode.
///
/// \return \c true if a pointer type was unwrapped, \c false if we reached a
/// pair of types that can't be unwrapped further.
bool ASTContext::UnwrapSimilarTypes(QualType &T1, QualType &T2,
                                    bool AllowPiMismatch) const {
  UnwrapSimilarArrayTypes(T1, T2, AllowPiMismatch);
 
  const auto *T1PtrType = T1->getAs<PointerType>();
  const auto *T2PtrType = T2->getAs<PointerType>();
  if (T1PtrType && T2PtrType) {
    T1 = T1PtrType->getPointeeType();
    T2 = T2PtrType->getPointeeType();
    return true;
  }
 
  if (const auto *T1MPType = T1->getAs<MemberPointerType>(),
      *T2MPType = T2->getAs<MemberPointerType>();
      T1MPType && T2MPType) {
    if (auto *RD1 = T1MPType->getMostRecentCXXRecordDecl(),
        *RD2 = T2MPType->getMostRecentCXXRecordDecl();
        RD1 != RD2 && RD1->getCanonicalDecl() != RD2->getCanonicalDecl())
      return false;
    if (T1MPType->getQualifier().getCanonical() !=
        T2MPType->getQualifier().getCanonical())
      return false;
    T1 = T1MPType->getPointeeType();
    T2 = T2MPType->getPointeeType();
    return true;
  }
 
  if (getLangOpts().ObjC) {
    const auto *T1OPType = T1->getAs<ObjCObjectPointerType>();
    const auto *T2OPType = T2->getAs<ObjCObjectPointerType>();
    if (T1OPType && T2OPType) {
      T1 = T1OPType->getPointeeType();
      T2 = T2OPType->getPointeeType();
      return true;
    }
  }
 
  // FIXME: Block pointers, too?
 
  return false;
}
 
bool ASTContext::hasSimilarType(QualType T1, QualType T2) const {
  while (true) {
    Qualifiers Quals;
    T1 = getUnqualifiedArrayType(T1, Quals);
    T2 = getUnqualifiedArrayType(T2, Quals);
    if (hasSameType(T1, T2))
      return true;
    if (!UnwrapSimilarTypes(T1, T2))
      return false;
  }
}
 
bool ASTContext::hasCvrSimilarType(QualType T1, QualType T2) {
  while (true) {
    Qualifiers Quals1, Quals2;
    T1 = getUnqualifiedArrayType(T1, Quals1);
    T2 = getUnqualifiedArrayType(T2, Quals2);
 
    Quals1.removeCVRQualifiers();
    Quals2.removeCVRQualifiers();
    if (Quals1 != Quals2)
      return false;
 
    if (hasSameType(T1, T2))
      return true;
 
    if (!UnwrapSimilarTypes(T1, T2, /*AllowPiMismatch*/ false))
      return false;
  }
}
 
DeclarationNameInfo
ASTContext::getNameForTemplate(TemplateName Name,
                               SourceLocation NameLoc) const {
  switch (Name.getKind()) {
  case TemplateName::QualifiedTemplate:
  case TemplateName::Template:
    // DNInfo work in progress: CHECKME: what about DNLoc?
    return DeclarationNameInfo(Name.getAsTemplateDecl()->getDeclName(),
                               NameLoc);
 
  case TemplateName::OverloadedTemplate: {
    OverloadedTemplateStorage *Storage = Name.getAsOverloadedTemplate();
    // DNInfo work in progress: CHECKME: what about DNLoc?
    return DeclarationNameInfo((*Storage->begin())->getDeclName(), NameLoc);
  }
 
  case TemplateName::AssumedTemplate: {
    AssumedTemplateStorage *Storage = Name.getAsAssumedTemplateName();
    return DeclarationNameInfo(Storage->getDeclName(), NameLoc);
  }
 
  case TemplateName::DependentTemplate: {
    DependentTemplateName *DTN = Name.getAsDependentTemplateName();
    IdentifierOrOverloadedOperator TN = DTN->getName();
    DeclarationName DName;
    if (const IdentifierInfo *II = TN.getIdentifier()) {
      DName = DeclarationNames.getIdentifier(II);
      return DeclarationNameInfo(DName, NameLoc);
    } else {
      DName = DeclarationNames.getCXXOperatorName(TN.getOperator());
      // DNInfo work in progress: FIXME: source locations?
      DeclarationNameLoc DNLoc =
          DeclarationNameLoc::makeCXXOperatorNameLoc(SourceRange());
      return DeclarationNameInfo(DName, NameLoc, DNLoc);
    }
  }
 
  case TemplateName::SubstTemplateTemplateParm: {
    SubstTemplateTemplateParmStorage *subst
      = Name.getAsSubstTemplateTemplateParm();
    return DeclarationNameInfo(subst->getParameter()->getDeclName(),
                               NameLoc);
  }
 
  case TemplateName::SubstTemplateTemplateParmPack: {
    SubstTemplateTemplateParmPackStorage *subst
      = Name.getAsSubstTemplateTemplateParmPack();
    return DeclarationNameInfo(subst->getParameterPack()->getDeclName(),
                               NameLoc);
  }
  case TemplateName::UsingTemplate:
    return DeclarationNameInfo(Name.getAsUsingShadowDecl()->getDeclName(),
                               NameLoc);
  case TemplateName::DeducedTemplate: {
    DeducedTemplateStorage *DTS = Name.getAsDeducedTemplateName();
    return getNameForTemplate(DTS->getUnderlying(), NameLoc);
  }
  }
 
  llvm_unreachable("bad template name kind!");
}
 
static const TemplateArgument *
getDefaultTemplateArgumentOrNone(const NamedDecl *P) {
  auto handleParam = [](auto *TP) -> const TemplateArgument * {
    if (!TP->hasDefaultArgument())
      return nullptr;
    return &TP->getDefaultArgument().getArgument();
  };
  switch (P->getKind()) {
  case NamedDecl::TemplateTypeParm:
    return handleParam(cast<TemplateTypeParmDecl>(P));
  case NamedDecl::NonTypeTemplateParm:
    return handleParam(cast<NonTypeTemplateParmDecl>(P));
  case NamedDecl::TemplateTemplateParm:
    return handleParam(cast<TemplateTemplateParmDecl>(P));
  default:
    llvm_unreachable("Unexpected template parameter kind");
  }
}
 
TemplateName ASTContext::getCanonicalTemplateName(TemplateName Name,
                                                  bool IgnoreDeduced) const {
  while (std::optional<TemplateName> UnderlyingOrNone =
             Name.desugar(IgnoreDeduced))
    Name = *UnderlyingOrNone;
 
  switch (Name.getKind()) {
  case TemplateName::Template: {
    TemplateDecl *Template = Name.getAsTemplateDecl();
    if (auto *TTP  = dyn_cast<TemplateTemplateParmDecl>(Template))
      Template = getCanonicalTemplateTemplateParmDecl(TTP);
 
    // The canonical template name is the canonical template declaration.
    return TemplateName(cast<TemplateDecl>(Template->getCanonicalDecl()));
  }
 
  case TemplateName::OverloadedTemplate:
  case TemplateName::AssumedTemplate:
    llvm_unreachable("cannot canonicalize unresolved template");
 
  case TemplateName::DependentTemplate: {
    DependentTemplateName *DTN = Name.getAsDependentTemplateName();
    assert(DTN && "Non-dependent template names must refer to template decls.");
    NestedNameSpecifier Qualifier = DTN->getQualifier();
    NestedNameSpecifier CanonQualifier = Qualifier.getCanonical();
    if (Qualifier != CanonQualifier || !DTN->hasTemplateKeyword())
      return getDependentTemplateName({CanonQualifier, DTN->getName(),
                                       /*HasTemplateKeyword=*/true});
    return Name;
  }
 
  case TemplateName::SubstTemplateTemplateParmPack: {
    SubstTemplateTemplateParmPackStorage *subst =
        Name.getAsSubstTemplateTemplateParmPack();
    TemplateArgument canonArgPack =
        getCanonicalTemplateArgument(subst->getArgumentPack());
    return getSubstTemplateTemplateParmPack(
        canonArgPack, subst->getAssociatedDecl()->getCanonicalDecl(),
        subst->getIndex(), subst->getFinal());
  }
  case TemplateName::DeducedTemplate: {
    assert(IgnoreDeduced == false);
    DeducedTemplateStorage *DTS = Name.getAsDeducedTemplateName();
    DefaultArguments DefArgs = DTS->getDefaultArguments();
    TemplateName Underlying = DTS->getUnderlying();
 
    TemplateName CanonUnderlying =
        getCanonicalTemplateName(Underlying, /*IgnoreDeduced=*/true);
    bool NonCanonical = CanonUnderlying != Underlying;
    auto CanonArgs =
        getCanonicalTemplateArguments(*this, DefArgs.Args, NonCanonical);
 
    ArrayRef<NamedDecl *> Params =
        CanonUnderlying.getAsTemplateDecl()->getTemplateParameters()->asArray();
    assert(CanonArgs.size() <= Params.size());
    // A deduced template name which deduces the same default arguments already
    // declared in the underlying template is the same template as the
    // underlying template. We need need to note any arguments which differ from
    // the corresponding declaration. If any argument differs, we must build a
    // deduced template name.
    for (int I = CanonArgs.size() - 1; I >= 0; --I) {
      const TemplateArgument *A = getDefaultTemplateArgumentOrNone(Params[I]);
      if (!A)
        break;
      auto CanonParamDefArg = getCanonicalTemplateArgument(*A);
      TemplateArgument &CanonDefArg = CanonArgs[I];
      if (CanonDefArg.structurallyEquals(CanonParamDefArg))
        continue;
      // Keep popping from the back any deault arguments which are the same.
      if (I == int(CanonArgs.size() - 1))
        CanonArgs.pop_back();
      NonCanonical = true;
    }
    return NonCanonical ? getDeducedTemplateName(
                              CanonUnderlying,
                              /*DefaultArgs=*/{DefArgs.StartPos, CanonArgs})
                        : Name;
  }
  case TemplateName::UsingTemplate:
  case TemplateName::QualifiedTemplate:
  case TemplateName::SubstTemplateTemplateParm:
    llvm_unreachable("always sugar node");
  }
 
  llvm_unreachable("bad template name!");
}
 
bool ASTContext::hasSameTemplateName(const TemplateName &X,
                                     const TemplateName &Y,
                                     bool IgnoreDeduced) const {
  return getCanonicalTemplateName(X, IgnoreDeduced) ==
         getCanonicalTemplateName(Y, IgnoreDeduced);
}
 
bool ASTContext::isSameAssociatedConstraint(
    const AssociatedConstraint &ACX, const AssociatedConstraint &ACY) const {
  if (ACX.ArgPackSubstIndex != ACY.ArgPackSubstIndex)
    return false;
  if (!isSameConstraintExpr(ACX.ConstraintExpr, ACY.ConstraintExpr))
    return false;
  return true;
}
 
bool ASTContext::isSameConstraintExpr(const Expr *XCE, const Expr *YCE) const {
  if (!XCE != !YCE)
    return false;
 
  if (!XCE)
    return true;
 
  llvm::FoldingSetNodeID XCEID, YCEID;
  XCE->Profile(XCEID, *this, /*Canonical=*/true, /*ProfileLambdaExpr=*/true);
  YCE->Profile(YCEID, *this, /*Canonical=*/true, /*ProfileLambdaExpr=*/true);
  return XCEID == YCEID;
}
 
bool ASTContext::isSameTypeConstraint(const TypeConstraint *XTC,
                                      const TypeConstraint *YTC) const {
  if (!XTC != !YTC)
    return false;
 
  if (!XTC)
    return true;
 
  auto *NCX = XTC->getNamedConcept();
  auto *NCY = YTC->getNamedConcept();
  if (!NCX || !NCY || !isSameEntity(NCX, NCY))
    return false;
  if (XTC->getConceptReference()->hasExplicitTemplateArgs() !=
      YTC->getConceptReference()->hasExplicitTemplateArgs())
    return false;
  if (XTC->getConceptReference()->hasExplicitTemplateArgs())
    if (XTC->getConceptReference()
            ->getTemplateArgsAsWritten()
            ->NumTemplateArgs !=
        YTC->getConceptReference()->getTemplateArgsAsWritten()->NumTemplateArgs)
      return false;
 
  // Compare slowly by profiling.
  //
  // We couldn't compare the profiling result for the template
  // args here. Consider the following example in different modules:
  //
  // template <__integer_like _Tp, C<_Tp> Sentinel>
  // constexpr _Tp operator()(_Tp &&__t, Sentinel &&last) const {
  //   return __t;
  // }
  //
  // When we compare the profiling result for `C<_Tp>` in different
  // modules, it will compare the type of `_Tp` in different modules.
  // However, the type of `_Tp` in different modules refer to different
  // types here naturally. So we couldn't compare the profiling result
  // for the template args directly.
  return isSameConstraintExpr(XTC->getImmediatelyDeclaredConstraint(),
                              YTC->getImmediatelyDeclaredConstraint());
}
 
bool ASTContext::isSameTemplateParameter(const NamedDecl *X,
                                         const NamedDecl *Y) const {
  if (X->getKind() != Y->getKind())
    return false;
 
  if (auto *TX = dyn_cast<TemplateTypeParmDecl>(X)) {
    auto *TY = cast<TemplateTypeParmDecl>(Y);
    if (TX->isParameterPack() != TY->isParameterPack())
      return false;
    if (TX->hasTypeConstraint() != TY->hasTypeConstraint())
      return false;
    return isSameTypeConstraint(TX->getTypeConstraint(),
                                TY->getTypeConstraint());
  }
 
  if (auto *TX = dyn_cast<NonTypeTemplateParmDecl>(X)) {
    auto *TY = cast<NonTypeTemplateParmDecl>(Y);
    return TX->isParameterPack() == TY->isParameterPack() &&
           TX->getASTContext().hasSameType(TX->getType(), TY->getType()) &&
           isSameConstraintExpr(TX->getPlaceholderTypeConstraint(),
                                TY->getPlaceholderTypeConstraint());
  }
 
  auto *TX = cast<TemplateTemplateParmDecl>(X);
  auto *TY = cast<TemplateTemplateParmDecl>(Y);
  return TX->isParameterPack() == TY->isParameterPack() &&
         isSameTemplateParameterList(TX->getTemplateParameters(),
                                     TY->getTemplateParameters());
}
 
bool ASTContext::isSameTemplateParameterList(
    const TemplateParameterList *X, const TemplateParameterList *Y) const {
  if (X->size() != Y->size())
    return false;
 
  for (unsigned I = 0, N = X->size(); I != N; ++I)
    if (!isSameTemplateParameter(X->getParam(I), Y->getParam(I)))
      return false;
 
  return isSameConstraintExpr(X->getRequiresClause(), Y->getRequiresClause());
}
 
bool ASTContext::isSameDefaultTemplateArgument(const NamedDecl *X,
                                               const NamedDecl *Y) const {
  // If the type parameter isn't the same already, we don't need to check the
  // default argument further.
  if (!isSameTemplateParameter(X, Y))
    return false;
 
  if (auto *TTPX = dyn_cast<TemplateTypeParmDecl>(X)) {
    auto *TTPY = cast<TemplateTypeParmDecl>(Y);
    if (!TTPX->hasDefaultArgument() || !TTPY->hasDefaultArgument())
      return false;
 
    return hasSameType(TTPX->getDefaultArgument().getArgument().getAsType(),
                       TTPY->getDefaultArgument().getArgument().getAsType());
  }
 
  if (auto *NTTPX = dyn_cast<NonTypeTemplateParmDecl>(X)) {
    auto *NTTPY = cast<NonTypeTemplateParmDecl>(Y);
    if (!NTTPX->hasDefaultArgument() || !NTTPY->hasDefaultArgument())
      return false;
 
    Expr *DefaultArgumentX =
        NTTPX->getDefaultArgument().getArgument().getAsExpr()->IgnoreImpCasts();
    Expr *DefaultArgumentY =
        NTTPY->getDefaultArgument().getArgument().getAsExpr()->IgnoreImpCasts();
    llvm::FoldingSetNodeID XID, YID;
    DefaultArgumentX->Profile(XID, *this, /*Canonical=*/true);
    DefaultArgumentY->Profile(YID, *this, /*Canonical=*/true);
    return XID == YID;
  }
 
  auto *TTPX = cast<TemplateTemplateParmDecl>(X);
  auto *TTPY = cast<TemplateTemplateParmDecl>(Y);
 
  if (!TTPX->hasDefaultArgument() || !TTPY->hasDefaultArgument())
    return false;
 
  const TemplateArgument &TAX = TTPX->getDefaultArgument().getArgument();
  const TemplateArgument &TAY = TTPY->getDefaultArgument().getArgument();
  return hasSameTemplateName(TAX.getAsTemplate(), TAY.getAsTemplate());
}
 
static bool isSameQualifier(const NestedNameSpecifier X,
                            const NestedNameSpecifier Y) {
  if (X == Y)
    return true;
  if (!X || !Y)
    return false;
 
  auto Kind = X.getKind();
  if (Kind != Y.getKind())
    return false;
 
  // FIXME: For namespaces and types, we're permitted to check that the entity
  // is named via the same tokens. We should probably do so.
  switch (Kind) {
  case NestedNameSpecifier::Kind::Namespace: {
    auto [NamespaceX, PrefixX] = X.getAsNamespaceAndPrefix();
    auto [NamespaceY, PrefixY] = Y.getAsNamespaceAndPrefix();
    if (!declaresSameEntity(NamespaceX->getNamespace(),
                            NamespaceY->getNamespace()))
      return false;
    return isSameQualifier(PrefixX, PrefixY);
  }
  case NestedNameSpecifier::Kind::Type: {
    const auto *TX = X.getAsType(), *TY = Y.getAsType();
    if (TX->getCanonicalTypeInternal() != TY->getCanonicalTypeInternal())
      return false;
    return isSameQualifier(TX->getPrefix(), TY->getPrefix());
  }
  case NestedNameSpecifier::Kind::Null:
  case NestedNameSpecifier::Kind::Global:
  case NestedNameSpecifier::Kind::MicrosoftSuper:
    return true;
  }
  llvm_unreachable("unhandled qualifier kind");
}
 
static bool hasSameCudaAttrs(const FunctionDecl *A, const FunctionDecl *B) {
  if (!A->getASTContext().getLangOpts().CUDA)
    return true; // Target attributes are overloadable in CUDA compilation only.
  if (A->hasAttr<CUDADeviceAttr>() != B->hasAttr<CUDADeviceAttr>())
    return false;
  if (A->hasAttr<CUDADeviceAttr>() && B->hasAttr<CUDADeviceAttr>())
    return A->hasAttr<CUDAHostAttr>() == B->hasAttr<CUDAHostAttr>();
  return true; // unattributed and __host__ functions are the same.
}
 
/// Determine whether the attributes we can overload on are identical for A and
/// B. Will ignore any overloadable attrs represented in the type of A and B.
static bool hasSameOverloadableAttrs(const FunctionDecl *A,
                                     const FunctionDecl *B) {
  // Note that pass_object_size attributes are represented in the function's
  // ExtParameterInfo, so we don't need to check them here.
 
  llvm::FoldingSetNodeID Cand1ID, Cand2ID;
  auto AEnableIfAttrs = A->specific_attrs<EnableIfAttr>();
  auto BEnableIfAttrs = B->specific_attrs<EnableIfAttr>();
 
  for (auto Pair : zip_longest(AEnableIfAttrs, BEnableIfAttrs)) {
    std::optional<EnableIfAttr *> Cand1A = std::get<0>(Pair);
    std::optional<EnableIfAttr *> Cand2A = std::get<1>(Pair);
 
    // Return false if the number of enable_if attributes is different.
    if (!Cand1A || !Cand2A)
      return false;
 
    Cand1ID.clear();
    Cand2ID.clear();
 
    (*Cand1A)->getCond()->Profile(Cand1ID, A->getASTContext(), true);
    (*Cand2A)->getCond()->Profile(Cand2ID, B->getASTContext(), true);
 
    // Return false if any of the enable_if expressions of A and B are
    // different.
    if (Cand1ID != Cand2ID)
      return false;
  }
  return hasSameCudaAttrs(A, B);
}
 
bool ASTContext::isSameEntity(const NamedDecl *X, const NamedDecl *Y) const {
  // Caution: this function is called by the AST reader during deserialization,
  // so it cannot rely on AST invariants being met. Non-trivial accessors
  // should be avoided, along with any traversal of redeclaration chains.
 
  if (X == Y)
    return true;
 
  if (X->getDeclName() != Y->getDeclName())
    return false;
 
  // Must be in the same context.
  //
  // Note that we can't use DeclContext::Equals here, because the DeclContexts
  // could be two different declarations of the same function. (We will fix the
  // semantic DC to refer to the primary definition after merging.)
  if (!declaresSameEntity(cast<Decl>(X->getDeclContext()->getRedeclContext()),
                          cast<Decl>(Y->getDeclContext()->getRedeclContext())))
    return false;
 
  // If either X or Y are local to the owning module, they are only possible to
  // be the same entity if they are in the same module.
  if (X->isModuleLocal() || Y->isModuleLocal())
    if (!isInSameModule(X->getOwningModule(), Y->getOwningModule()))
      return false;
 
  // Two typedefs refer to the same entity if they have the same underlying
  // type.
  if (const auto *TypedefX = dyn_cast<TypedefNameDecl>(X))
    if (const auto *TypedefY = dyn_cast<TypedefNameDecl>(Y))
      return hasSameType(TypedefX->getUnderlyingType(),
                         TypedefY->getUnderlyingType());
 
  // Must have the same kind.
  if (X->getKind() != Y->getKind())
    return false;
 
  // Objective-C classes and protocols with the same name always match.
  if (isa<ObjCInterfaceDecl>(X) || isa<ObjCProtocolDecl>(X))
    return true;
 
  if (isa<ClassTemplateSpecializationDecl>(X)) {
    // No need to handle these here: we merge them when adding them to the
    // template.
    return false;
  }
 
  // Compatible tags match.
  if (const auto *TagX = dyn_cast<TagDecl>(X)) {
    const auto *TagY = cast<TagDecl>(Y);
    return (TagX->getTagKind() == TagY->getTagKind()) ||
           ((TagX->getTagKind() == TagTypeKind::Struct ||
             TagX->getTagKind() == TagTypeKind::Class ||
             TagX->getTagKind() == TagTypeKind::Interface) &&
            (TagY->getTagKind() == TagTypeKind::Struct ||
             TagY->getTagKind() == TagTypeKind::Class ||
             TagY->getTagKind() == TagTypeKind::Interface));
  }
 
  // Functions with the same type and linkage match.
  // FIXME: This needs to cope with merging of prototyped/non-prototyped
  // functions, etc.
  if (const auto *FuncX = dyn_cast<FunctionDecl>(X)) {
    const auto *FuncY = cast<FunctionDecl>(Y);
    if (const auto *CtorX = dyn_cast<CXXConstructorDecl>(X)) {
      const auto *CtorY = cast<CXXConstructorDecl>(Y);
      if (CtorX->getInheritedConstructor() &&
          !isSameEntity(CtorX->getInheritedConstructor().getConstructor(),
                        CtorY->getInheritedConstructor().getConstructor()))
        return false;
    }
 
    if (FuncX->isMultiVersion() != FuncY->isMultiVersion())
      return false;
 
    // Multiversioned functions with different feature strings are represented
    // as separate declarations.
    if (FuncX->isMultiVersion()) {
      const auto *TAX = FuncX->getAttr<TargetAttr>();
      const auto *TAY = FuncY->getAttr<TargetAttr>();
      assert(TAX && TAY && "Multiversion Function without target attribute");
 
      if (TAX->getFeaturesStr() != TAY->getFeaturesStr())
        return false;
    }
 
    // Per C++20 [temp.over.link]/4, friends in different classes are sometimes
    // not the same entity if they are constrained.
    if ((FuncX->isMemberLikeConstrainedFriend() ||
         FuncY->isMemberLikeConstrainedFriend()) &&
        !FuncX->getLexicalDeclContext()->Equals(
            FuncY->getLexicalDeclContext())) {
      return false;
    }
 
    if (!isSameAssociatedConstraint(FuncX->getTrailingRequiresClause(),
                                    FuncY->getTrailingRequiresClause()))
      return false;
 
    auto GetTypeAsWritten = [](const FunctionDecl *FD) {
      // Map to the first declaration that we've already merged into this one.
      // The TSI of redeclarations might not match (due to calling conventions
      // being inherited onto the type but not the TSI), but the TSI type of
      // the first declaration of the function should match across modules.
      FD = FD->getCanonicalDecl();
      return FD->getTypeSourceInfo() ? FD->getTypeSourceInfo()->getType()
                                     : FD->getType();
    };
    QualType XT = GetTypeAsWritten(FuncX), YT = GetTypeAsWritten(FuncY);
    if (!hasSameType(XT, YT)) {
      // We can get functions with different types on the redecl chain in C++17
      // if they have differing exception specifications and at least one of
      // the excpetion specs is unresolved.
      auto *XFPT = XT->getAs<FunctionProtoType>();
      auto *YFPT = YT->getAs<FunctionProtoType>();
      if (getLangOpts().CPlusPlus17 && XFPT && YFPT &&
          (isUnresolvedExceptionSpec(XFPT->getExceptionSpecType()) ||
           isUnresolvedExceptionSpec(YFPT->getExceptionSpecType())) &&
          hasSameFunctionTypeIgnoringExceptionSpec(XT, YT))
        return true;
      return false;
    }
 
    return FuncX->getLinkageInternal() == FuncY->getLinkageInternal() &&
           hasSameOverloadableAttrs(FuncX, FuncY);
  }
 
  // Variables with the same type and linkage match.
  if (const auto *VarX = dyn_cast<VarDecl>(X)) {
    const auto *VarY = cast<VarDecl>(Y);
    if (VarX->getLinkageInternal() == VarY->getLinkageInternal()) {
      // During deserialization, we might compare variables before we load
      // their types. Assume the types will end up being the same.
      if (VarX->getType().isNull() || VarY->getType().isNull())
        return true;
 
      if (hasSameType(VarX->getType(), VarY->getType()))
        return true;
 
      // We can get decls with different types on the redecl chain. Eg.
      // template <typename T> struct S { static T Var[]; }; // #1
      // template <typename T> T S<T>::Var[sizeof(T)]; // #2
      // Only? happens when completing an incomplete array type. In this case
      // when comparing #1 and #2 we should go through their element type.
      const ArrayType *VarXTy = getAsArrayType(VarX->getType());
      const ArrayType *VarYTy = getAsArrayType(VarY->getType());
      if (!VarXTy || !VarYTy)
        return false;
      if (VarXTy->isIncompleteArrayType() || VarYTy->isIncompleteArrayType())
        return hasSameType(VarXTy->getElementType(), VarYTy->getElementType());
    }
    return false;
  }
 
  // Namespaces with the same name and inlinedness match.
  if (const auto *NamespaceX = dyn_cast<NamespaceDecl>(X)) {
    const auto *NamespaceY = cast<NamespaceDecl>(Y);
    return NamespaceX->isInline() == NamespaceY->isInline();
  }
 
  // Identical template names and kinds match if their template parameter lists
  // and patterns match.
  if (const auto *TemplateX = dyn_cast<TemplateDecl>(X)) {
    const auto *TemplateY = cast<TemplateDecl>(Y);
 
    // ConceptDecl wouldn't be the same if their constraint expression differs.
    if (const auto *ConceptX = dyn_cast<ConceptDecl>(X)) {
      const auto *ConceptY = cast<ConceptDecl>(Y);
      if (!isSameConstraintExpr(ConceptX->getConstraintExpr(),
                                ConceptY->getConstraintExpr()))
        return false;
    }
 
    return isSameEntity(TemplateX->getTemplatedDecl(),
                        TemplateY->getTemplatedDecl()) &&
           isSameTemplateParameterList(TemplateX->getTemplateParameters(),
                                       TemplateY->getTemplateParameters());
  }
 
  // Fields with the same name and the same type match.
  if (const auto *FDX = dyn_cast<FieldDecl>(X)) {
    const auto *FDY = cast<FieldDecl>(Y);
    // FIXME: Also check the bitwidth is odr-equivalent, if any.
    return hasSameType(FDX->getType(), FDY->getType());
  }
 
  // Indirect fields with the same target field match.
  if (const auto *IFDX = dyn_cast<IndirectFieldDecl>(X)) {
    const auto *IFDY = cast<IndirectFieldDecl>(Y);
    return IFDX->getAnonField()->getCanonicalDecl() ==
           IFDY->getAnonField()->getCanonicalDecl();
  }
 
  // Enumerators with the same name match.
  if (isa<EnumConstantDecl>(X))
    // FIXME: Also check the value is odr-equivalent.
    return true;
 
  // Using shadow declarations with the same target match.
  if (const auto *USX = dyn_cast<UsingShadowDecl>(X)) {
    const auto *USY = cast<UsingShadowDecl>(Y);
    return declaresSameEntity(USX->getTargetDecl(), USY->getTargetDecl());
  }
 
  // Using declarations with the same qualifier match. (We already know that
  // the name matches.)
  if (const auto *UX = dyn_cast<UsingDecl>(X)) {
    const auto *UY = cast<UsingDecl>(Y);
    return isSameQualifier(UX->getQualifier(), UY->getQualifier()) &&
           UX->hasTypename() == UY->hasTypename() &&
           UX->isAccessDeclaration() == UY->isAccessDeclaration();
  }
  if (const auto *UX = dyn_cast<UnresolvedUsingValueDecl>(X)) {
    const auto *UY = cast<UnresolvedUsingValueDecl>(Y);
    return isSameQualifier(UX->getQualifier(), UY->getQualifier()) &&
           UX->isAccessDeclaration() == UY->isAccessDeclaration();
  }
  if (const auto *UX = dyn_cast<UnresolvedUsingTypenameDecl>(X)) {
    return isSameQualifier(
        UX->getQualifier(),
        cast<UnresolvedUsingTypenameDecl>(Y)->getQualifier());
  }
 
  // Using-pack declarations are only created by instantiation, and match if
  // they're instantiated from matching UnresolvedUsing...Decls.
  if (const auto *UX = dyn_cast<UsingPackDecl>(X)) {
    return declaresSameEntity(
        UX->getInstantiatedFromUsingDecl(),
        cast<UsingPackDecl>(Y)->getInstantiatedFromUsingDecl());
  }
 
  // Namespace alias definitions with the same target match.
  if (const auto *NAX = dyn_cast<NamespaceAliasDecl>(X)) {
    const auto *NAY = cast<NamespaceAliasDecl>(Y);
    return NAX->getNamespace()->Equals(NAY->getNamespace());
  }
 
  return false;
}
 
TemplateArgument
ASTContext::getCanonicalTemplateArgument(const TemplateArgument &Arg) const {
  switch (Arg.getKind()) {
    case TemplateArgument::Null:
      return Arg;
 
    case TemplateArgument::Expression:
      return TemplateArgument(Arg.getAsExpr(), /*IsCanonical=*/true,
                              Arg.getIsDefaulted());
 
    case TemplateArgument::Declaration: {
      auto *D = cast<ValueDecl>(Arg.getAsDecl()->getCanonicalDecl());
      return TemplateArgument(D, getCanonicalType(Arg.getParamTypeForDecl()),
                              Arg.getIsDefaulted());
    }
 
    case TemplateArgument::NullPtr:
      return TemplateArgument(getCanonicalType(Arg.getNullPtrType()),
                              /*isNullPtr*/ true, Arg.getIsDefaulted());
 
    case TemplateArgument::Template:
      return TemplateArgument(getCanonicalTemplateName(Arg.getAsTemplate()),
                              Arg.getIsDefaulted());
 
    case TemplateArgument::TemplateExpansion:
      return TemplateArgument(
          getCanonicalTemplateName(Arg.getAsTemplateOrTemplatePattern()),
          Arg.getNumTemplateExpansions(), Arg.getIsDefaulted());
 
    case TemplateArgument::Integral:
      return TemplateArgument(Arg, getCanonicalType(Arg.getIntegralType()));
 
    case TemplateArgument::StructuralValue:
      return TemplateArgument(*this,
                              getCanonicalType(Arg.getStructuralValueType()),
                              Arg.getAsStructuralValue(), Arg.getIsDefaulted());
 
    case TemplateArgument::Type:
      return TemplateArgument(getCanonicalType(Arg.getAsType()),
                              /*isNullPtr*/ false, Arg.getIsDefaulted());
 
    case TemplateArgument::Pack: {
      bool AnyNonCanonArgs = false;
      auto CanonArgs = ::getCanonicalTemplateArguments(
          *this, Arg.pack_elements(), AnyNonCanonArgs);
      if (!AnyNonCanonArgs)
        return Arg;
      auto NewArg = TemplateArgument::CreatePackCopy(
          const_cast<ASTContext &>(*this), CanonArgs);
      NewArg.setIsDefaulted(Arg.getIsDefaulted());
      return NewArg;
    }
  }
 
  // Silence GCC warning
  llvm_unreachable("Unhandled template argument kind");
}
 
bool ASTContext::isSameTemplateArgument(const TemplateArgument &Arg1,
                                        const TemplateArgument &Arg2) const {
  if (Arg1.getKind() != Arg2.getKind())
    return false;
 
  switch (Arg1.getKind()) {
  case TemplateArgument::Null:
    llvm_unreachable("Comparing NULL template argument");
 
  case TemplateArgument::Type:
    return hasSameType(Arg1.getAsType(), Arg2.getAsType());
 
  case TemplateArgument::Declaration:
    return Arg1.getAsDecl()->getUnderlyingDecl()->getCanonicalDecl() ==
           Arg2.getAsDecl()->getUnderlyingDecl()->getCanonicalDecl();
 
  case TemplateArgument::NullPtr:
    return hasSameType(Arg1.getNullPtrType(), Arg2.getNullPtrType());
 
  case TemplateArgument::Template:
  case TemplateArgument::TemplateExpansion:
    return getCanonicalTemplateName(Arg1.getAsTemplateOrTemplatePattern()) ==
           getCanonicalTemplateName(Arg2.getAsTemplateOrTemplatePattern());
 
  case TemplateArgument::Integral:
    return llvm::APSInt::isSameValue(Arg1.getAsIntegral(),
                                     Arg2.getAsIntegral());
 
  case TemplateArgument::StructuralValue:
    return Arg1.structurallyEquals(Arg2);
 
  case TemplateArgument::Expression: {
    llvm::FoldingSetNodeID ID1, ID2;
    Arg1.getAsExpr()->Profile(ID1, *this, /*Canonical=*/true);
    Arg2.getAsExpr()->Profile(ID2, *this, /*Canonical=*/true);
    return ID1 == ID2;
  }
 
  case TemplateArgument::Pack:
    return llvm::equal(
        Arg1.getPackAsArray(), Arg2.getPackAsArray(),
        [&](const TemplateArgument &Arg1, const TemplateArgument &Arg2) {
          return isSameTemplateArgument(Arg1, Arg2);
        });
  }
 
  llvm_unreachable("Unhandled template argument kind");
}
 
const ArrayType *ASTContext::getAsArrayType(QualType T) const {
  // Handle the non-qualified case efficiently.
  if (!T.hasLocalQualifiers()) {
    // Handle the common positive case fast.
    if (const auto *AT = dyn_cast<ArrayType>(T))
      return AT;
  }
 
  // Handle the common negative case fast.
  if (!isa<ArrayType>(T.getCanonicalType()))
    return nullptr;
 
  // Apply any qualifiers from the array type to the element type.  This
  // implements C99 6.7.3p8: "If the specification of an array type includes
  // any type qualifiers, the element type is so qualified, not the array type."
 
  // If we get here, we either have type qualifiers on the type, or we have
  // sugar such as a typedef in the way.  If we have type qualifiers on the type
  // we must propagate them down into the element type.
 
  SplitQualType split = T.getSplitDesugaredType();
  Qualifiers qs = split.Quals;
 
  // If we have a simple case, just return now.
  const auto *ATy = dyn_cast<ArrayType>(split.Ty);
  if (!ATy || qs.empty())
    return ATy;
 
  // Otherwise, we have an array and we have qualifiers on it.  Push the
  // qualifiers into the array element type and return a new array type.
  QualType NewEltTy = getQualifiedType(ATy->getElementType(), qs);
 
  if (const auto *CAT = dyn_cast<ConstantArrayType>(ATy))
    return cast<ArrayType>(getConstantArrayType(NewEltTy, CAT->getSize(),
                                                CAT->getSizeExpr(),
                                                CAT->getSizeModifier(),
                                           CAT->getIndexTypeCVRQualifiers()));
  if (const auto *IAT = dyn_cast<IncompleteArrayType>(ATy))
    return cast<ArrayType>(getIncompleteArrayType(NewEltTy,
                                                  IAT->getSizeModifier(),
                                           IAT->getIndexTypeCVRQualifiers()));
 
  if (const auto *DSAT = dyn_cast<DependentSizedArrayType>(ATy))
    return cast<ArrayType>(getDependentSizedArrayType(
        NewEltTy, DSAT->getSizeExpr(), DSAT->getSizeModifier(),
        DSAT->getIndexTypeCVRQualifiers()));
 
  const auto *VAT = cast<VariableArrayType>(ATy);
  return cast<ArrayType>(
      getVariableArrayType(NewEltTy, VAT->getSizeExpr(), VAT->getSizeModifier(),
                           VAT->getIndexTypeCVRQualifiers()));
}
 
QualType ASTContext::getAdjustedParameterType(QualType T) const {
  if (getLangOpts().HLSL && T->isConstantArrayType())
    return getArrayParameterType(T);
  if (T->isArrayType() || T->isFunctionType())
    return getDecayedType(T);
  return T;
}
 
QualType ASTContext::getSignatureParameterType(QualType T) const {
  T = getVariableArrayDecayedType(T);
  T = getAdjustedParameterType(T);
  return T.getUnqualifiedType();
}
 
QualType ASTContext::getExceptionObjectType(QualType T) const {
  // C++ [except.throw]p3:
  //   A throw-expression initializes a temporary object, called the exception
  //   object, the type of which is determined by removing any top-level
  //   cv-qualifiers from the static type of the operand of throw and adjusting
  //   the type from "array of T" or "function returning T" to "pointer to T"
  //   or "pointer to function returning T", [...]
  T = getVariableArrayDecayedType(T);
  if (T->isArrayType() || T->isFunctionType())
    T = getDecayedType(T);
  return T.getUnqualifiedType();
}
 
/// getArrayDecayedType - Return the properly qualified result of decaying the
/// specified array type to a pointer.  This operation is non-trivial when
/// handling typedefs etc.  The canonical type of "T" must be an array type,
/// this returns a pointer to a properly qualified element of the array.
///
/// See C99 6.7.5.3p7 and C99 6.3.2.1p3.
QualType ASTContext::getArrayDecayedType(QualType Ty) const {
  // Get the element type with 'getAsArrayType' so that we don't lose any
  // typedefs in the element type of the array.  This also handles propagation
  // of type qualifiers from the array type into the element type if present
  // (C99 6.7.3p8).
  const ArrayType *PrettyArrayType = getAsArrayType(Ty);
  assert(PrettyArrayType && "Not an array type!");
 
  QualType PtrTy = getPointerType(PrettyArrayType->getElementType());
 
  // int x[restrict 4] ->  int *restrict
  QualType Result = getQualifiedType(PtrTy,
                                     PrettyArrayType->getIndexTypeQualifiers());
 
  // int x[_Nullable] -> int * _Nullable
  if (auto Nullability = Ty->getNullability()) {
    Result = const_cast<ASTContext *>(this)->getAttributedType(*Nullability,
                                                               Result, Result);
  }
  return Result;
}
 
QualType ASTContext::getBaseElementType(const ArrayType *array) const {
  return getBaseElementType(array->getElementType());
}
 
QualType ASTContext::getBaseElementType(QualType type) const {
  Qualifiers qs;
  while (true) {
    SplitQualType split = type.getSplitDesugaredType();
    const ArrayType *array = split.Ty->getAsArrayTypeUnsafe();
    if (!array) break;
 
    type = array->getElementType();
    qs.addConsistentQualifiers(split.Quals);
  }
 
  return getQualifiedType(type, qs);
}
 
/// getConstantArrayElementCount - Returns number of constant array elements.
uint64_t
ASTContext::getConstantArrayElementCount(const ConstantArrayType *CA)  const {
  uint64_t ElementCount = 1;
  do {
    ElementCount *= CA->getZExtSize();
    CA = dyn_cast_or_null<ConstantArrayType>(
      CA->getElementType()->getAsArrayTypeUnsafe());
  } while (CA);
  return ElementCount;
}
 
uint64_t ASTContext::getArrayInitLoopExprElementCount(
    const ArrayInitLoopExpr *AILE) const {
  if (!AILE)
    return 0;
 
  uint64_t ElementCount = 1;
 
  do {
    ElementCount *= AILE->getArraySize().getZExtValue();
    AILE = dyn_cast<ArrayInitLoopExpr>(AILE->getSubExpr());
  } while (AILE);
 
  return ElementCount;
}
 
/// getFloatingRank - Return a relative rank for floating point types.
/// This routine will assert if passed a built-in type that isn't a float.
static FloatingRank getFloatingRank(QualType T) {
  if (const auto *CT = T->getAs<ComplexType>())
    return getFloatingRank(CT->getElementType());
 
  switch (T->castAs<BuiltinType>()->getKind()) {
  default: llvm_unreachable("getFloatingRank(): not a floating type");
  case BuiltinType::Float16:    return Float16Rank;
  case BuiltinType::Half:       return HalfRank;
  case BuiltinType::Float:      return FloatRank;
  case BuiltinType::Double:     return DoubleRank;
  case BuiltinType::LongDouble: return LongDoubleRank;
  case BuiltinType::Float128:   return Float128Rank;
  case BuiltinType::BFloat16:   return BFloat16Rank;
  case BuiltinType::Ibm128:     return Ibm128Rank;
  }
}
 
/// getFloatingTypeOrder - Compare the rank of the two specified floating
/// point types, ignoring the domain of the type (i.e. 'double' ==
/// '_Complex double').  If LHS > RHS, return 1.  If LHS == RHS, return 0. If
/// LHS < RHS, return -1.
int ASTContext::getFloatingTypeOrder(QualType LHS, QualType RHS) const {
  FloatingRank LHSR = getFloatingRank(LHS);
  FloatingRank RHSR = getFloatingRank(RHS);
 
  if (LHSR == RHSR)
    return 0;
  if (LHSR > RHSR)
    return 1;
  return -1;
}
 
int ASTContext::getFloatingTypeSemanticOrder(QualType LHS, QualType RHS) const {
  if (&getFloatTypeSemantics(LHS) == &getFloatTypeSemantics(RHS))
    return 0;
  return getFloatingTypeOrder(LHS, RHS);
}
 
/// getIntegerRank - Return an integer conversion rank (C99 6.3.1.1p1). This
/// routine will assert if passed a built-in type that isn't an integer or enum,
/// or if it is not canonicalized.
unsigned ASTContext::getIntegerRank(const Type *T) const {
  assert(T->isCanonicalUnqualified() && "T should be canonicalized");
 
  // Results in this 'losing' to any type of the same size, but winning if
  // larger.
  if (const auto *EIT = dyn_cast<BitIntType>(T))
    return 0 + (EIT->getNumBits() << 3);
 
  switch (cast<BuiltinType>(T)->getKind()) {
  default: llvm_unreachable("getIntegerRank(): not a built-in integer");
  case BuiltinType::Bool:
    return 1 + (getIntWidth(BoolTy) << 3);
  case BuiltinType::Char_S:
  case BuiltinType::Char_U:
  case BuiltinType::SChar:
  case BuiltinType::UChar:
    return 2 + (getIntWidth(CharTy) << 3);
  case BuiltinType::Short:
  case BuiltinType::UShort:
    return 3 + (getIntWidth(ShortTy) << 3);
  case BuiltinType::Int:
  case BuiltinType::UInt:
    return 4 + (getIntWidth(IntTy) << 3);
  case BuiltinType::Long:
  case BuiltinType::ULong:
    return 5 + (getIntWidth(LongTy) << 3);
  case BuiltinType::LongLong:
  case BuiltinType::ULongLong:
    return 6 + (getIntWidth(LongLongTy) << 3);
  case BuiltinType::Int128:
  case BuiltinType::UInt128:
    return 7 + (getIntWidth(Int128Ty) << 3);
 
  // "The ranks of char8_t, char16_t, char32_t, and wchar_t equal the ranks of
  // their underlying types" [c++20 conv.rank]
  case BuiltinType::Char8:
    return getIntegerRank(UnsignedCharTy.getTypePtr());
  case BuiltinType::Char16:
    return getIntegerRank(
        getFromTargetType(Target->getChar16Type()).getTypePtr());
  case BuiltinType::Char32:
    return getIntegerRank(
        getFromTargetType(Target->getChar32Type()).getTypePtr());
  case BuiltinType::WChar_S:
  case BuiltinType::WChar_U:
    return getIntegerRank(
        getFromTargetType(Target->getWCharType()).getTypePtr());
  }
}
 
/// Whether this is a promotable bitfield reference according
/// to C99 6.3.1.1p2, bullet 2 (and GCC extensions).
///
/// \returns the type this bit-field will promote to, or NULL if no
/// promotion occurs.
QualType ASTContext::isPromotableBitField(Expr *E) const {
  if (E->isTypeDependent() || E->isValueDependent())
    return {};
 
  // C++ [conv.prom]p5:
  //    If the bit-field has an enumerated type, it is treated as any other
  //    value of that type for promotion purposes.
  if (getLangOpts().CPlusPlus && E->getType()->isEnumeralType())
    return {};
 
  // FIXME: We should not do this unless E->refersToBitField() is true. This
  // matters in C where getSourceBitField() will find bit-fields for various
  // cases where the source expression is not a bit-field designator.
 
  FieldDecl *Field = E->getSourceBitField(); // FIXME: conditional bit-fields?
  if (!Field)
    return {};
 
  QualType FT = Field->getType();
 
  uint64_t BitWidth = Field->getBitWidthValue();
  uint64_t IntSize = getTypeSize(IntTy);
  // C++ [conv.prom]p5:
  //   A prvalue for an integral bit-field can be converted to a prvalue of type
  //   int if int can represent all the values of the bit-field; otherwise, it
  //   can be converted to unsigned int if unsigned int can represent all the
  //   values of the bit-field. If the bit-field is larger yet, no integral
  //   promotion applies to it.
  // C11 6.3.1.1/2:
  //   [For a bit-field of type _Bool, int, signed int, or unsigned int:]
  //   If an int can represent all values of the original type (as restricted by
  //   the width, for a bit-field), the value is converted to an int; otherwise,
  //   it is converted to an unsigned int.
  //
  // FIXME: C does not permit promotion of a 'long : 3' bitfield to int.
  //        We perform that promotion here to match GCC and C++.
  // FIXME: C does not permit promotion of an enum bit-field whose rank is
  //        greater than that of 'int'. We perform that promotion to match GCC.
  //
  // C23 6.3.1.1p2:
  //   The value from a bit-field of a bit-precise integer type is converted to
  //   the corresponding bit-precise integer type. (The rest is the same as in
  //   C11.)
  if (QualType QT = Field->getType(); QT->isBitIntType())
    return QT;
 
  if (BitWidth < IntSize)
    return IntTy;
 
  if (BitWidth == IntSize)
    return FT->isSignedIntegerType() ? IntTy : UnsignedIntTy;
 
  // Bit-fields wider than int are not subject to promotions, and therefore act
  // like the base type. GCC has some weird bugs in this area that we
  // deliberately do not follow (GCC follows a pre-standard resolution to
  // C's DR315 which treats bit-width as being part of the type, and this leaks
  // into their semantics in some cases).
  return {};
}
 
/// getPromotedIntegerType - Returns the type that Promotable will
/// promote to: C99 6.3.1.1p2, assuming that Promotable is a promotable
/// integer type.
QualType ASTContext::getPromotedIntegerType(QualType Promotable) const {
  assert(!Promotable.isNull());
  assert(isPromotableIntegerType(Promotable));
  if (const auto *ED = Promotable->getAsEnumDecl())
    return ED->getPromotionType();
 
  if (const auto *BT = Promotable->getAs<BuiltinType>()) {
    // C++ [conv.prom]: A prvalue of type char16_t, char32_t, or wchar_t
    // (3.9.1) can be converted to a prvalue of the first of the following
    // types that can represent all the values of its underlying type:
    // int, unsigned int, long int, unsigned long int, long long int, or
    // unsigned long long int [...]
    // FIXME: Is there some better way to compute this?
    if (BT->getKind() == BuiltinType::WChar_S ||
        BT->getKind() == BuiltinType::WChar_U ||
        BT->getKind() == BuiltinType::Char8 ||
        BT->getKind() == BuiltinType::Char16 ||
        BT->getKind() == BuiltinType::Char32) {
      bool FromIsSigned = BT->getKind() == BuiltinType::WChar_S;
      uint64_t FromSize = getTypeSize(BT);
      QualType PromoteTypes[] = { IntTy, UnsignedIntTy, LongTy, UnsignedLongTy,
                                  LongLongTy, UnsignedLongLongTy };
      for (const auto &PT : PromoteTypes) {
        uint64_t ToSize = getTypeSize(PT);
        if (FromSize < ToSize ||
            (FromSize == ToSize && FromIsSigned == PT->isSignedIntegerType()))
          return PT;
      }
      llvm_unreachable("char type should fit into long long");
    }
  }
 
  // At this point, we should have a signed or unsigned integer type.
  if (Promotable->isSignedIntegerType())
    return IntTy;
  uint64_t PromotableSize = getIntWidth(Promotable);
  uint64_t IntSize = getIntWidth(IntTy);
  assert(Promotable->isUnsignedIntegerType() && PromotableSize <= IntSize);
  return (PromotableSize != IntSize) ? IntTy : UnsignedIntTy;
}
 
/// Recurses in pointer/array types until it finds an objc retainable
/// type and returns its ownership.
Qualifiers::ObjCLifetime ASTContext::getInnerObjCOwnership(QualType T) const {
  while (!T.isNull()) {
    if (T.getObjCLifetime() != Qualifiers::OCL_None)
      return T.getObjCLifetime();
    if (T->isArrayType())
      T = getBaseElementType(T);
    else if (const auto *PT = T->getAs<PointerType>())
      T = PT->getPointeeType();
    else if (const auto *RT = T->getAs<ReferenceType>())
      T = RT->getPointeeType();
    else
      break;
  }
 
  return Qualifiers::OCL_None;
}
 
static const Type *getIntegerTypeForEnum(const EnumType *ET) {
  // Incomplete enum types are not treated as integer types.
  // FIXME: In C++, enum types are never integer types.
  const EnumDecl *ED = ET->getDecl()->getDefinitionOrSelf();
  if (ED->isComplete() && !ED->isScoped())
    return ED->getIntegerType().getTypePtr();
  return nullptr;
}
 
/// getIntegerTypeOrder - Returns the highest ranked integer type:
/// C99 6.3.1.8p1.  If LHS > RHS, return 1.  If LHS == RHS, return 0. If
/// LHS < RHS, return -1.
int ASTContext::getIntegerTypeOrder(QualType LHS, QualType RHS) const {
  const Type *LHSC = getCanonicalType(LHS).getTypePtr();
  const Type *RHSC = getCanonicalType(RHS).getTypePtr();
 
  // Unwrap enums to their underlying type.
  if (const auto *ET = dyn_cast<EnumType>(LHSC))
    LHSC = getIntegerTypeForEnum(ET);
  if (const auto *ET = dyn_cast<EnumType>(RHSC))
    RHSC = getIntegerTypeForEnum(ET);
 
  if (LHSC == RHSC) return 0;
 
  bool LHSUnsigned = LHSC->isUnsignedIntegerType();
  bool RHSUnsigned = RHSC->isUnsignedIntegerType();
 
  unsigned LHSRank = getIntegerRank(LHSC);
  unsigned RHSRank = getIntegerRank(RHSC);
 
  if (LHSUnsigned == RHSUnsigned) {  // Both signed or both unsigned.
    if (LHSRank == RHSRank) return 0;
    return LHSRank > RHSRank ? 1 : -1;
  }
 
  // Otherwise, the LHS is signed and the RHS is unsigned or visa versa.
  if (LHSUnsigned) {
    // If the unsigned [LHS] type is larger, return it.
    if (LHSRank >= RHSRank)
      return 1;
 
    // If the signed type can represent all values of the unsigned type, it
    // wins.  Because we are dealing with 2's complement and types that are
    // powers of two larger than each other, this is always safe.
    return -1;
  }
 
  // If the unsigned [RHS] type is larger, return it.
  if (RHSRank >= LHSRank)
    return -1;
 
  // If the signed type can represent all values of the unsigned type, it
  // wins.  Because we are dealing with 2's complement and types that are
  // powers of two larger than each other, this is always safe.
  return 1;
}
 
TypedefDecl *ASTContext::getCFConstantStringDecl() const {
  if (CFConstantStringTypeDecl)
    return CFConstantStringTypeDecl;
 
  assert(!CFConstantStringTagDecl &&
         "tag and typedef should be initialized together");
  CFConstantStringTagDecl = buildImplicitRecord("__NSConstantString_tag");
  CFConstantStringTagDecl->startDefinition();
 
  struct {
    QualType Type;
    const char *Name;
  } Fields[5];
  unsigned Count = 0;
 
  /// Objective-C ABI
  ///
  ///    typedef struct __NSConstantString_tag {
  ///      const int *isa;
  ///      int flags;
  ///      const char *str;
  ///      long length;
  ///    } __NSConstantString;
  ///
  /// Swift ABI (4.1, 4.2)
  ///
  ///    typedef struct __NSConstantString_tag {
  ///      uintptr_t _cfisa;
  ///      uintptr_t _swift_rc;
  ///      _Atomic(uint64_t) _cfinfoa;
  ///      const char *_ptr;
  ///      uint32_t _length;
  ///    } __NSConstantString;
  ///
  /// Swift ABI (5.0)
  ///
  ///    typedef struct __NSConstantString_tag {
  ///      uintptr_t _cfisa;
  ///      uintptr_t _swift_rc;
  ///      _Atomic(uint64_t) _cfinfoa;
  ///      const char *_ptr;
  ///      uintptr_t _length;
  ///    } __NSConstantString;
 
  const auto CFRuntime = getLangOpts().CFRuntime;
  if (static_cast<unsigned>(CFRuntime) <
      static_cast<unsigned>(LangOptions::CoreFoundationABI::Swift)) {
    Fields[Count++] = { getPointerType(IntTy.withConst()), "isa" };
    Fields[Count++] = { IntTy, "flags" };
    Fields[Count++] = { getPointerType(CharTy.withConst()), "str" };
    Fields[Count++] = { LongTy, "length" };
  } else {
    Fields[Count++] = { getUIntPtrType(), "_cfisa" };
    Fields[Count++] = { getUIntPtrType(), "_swift_rc" };
    Fields[Count++] = { getFromTargetType(Target->getUInt64Type()), "_swift_rc" };
    Fields[Count++] = { getPointerType(CharTy.withConst()), "_ptr" };
    if (CFRuntime == LangOptions::CoreFoundationABI::Swift4_1 ||
        CFRuntime == LangOptions::CoreFoundationABI::Swift4_2)
      Fields[Count++] = { IntTy, "_ptr" };
    else
      Fields[Count++] = { getUIntPtrType(), "_ptr" };
  }
 
  // Create fields
  for (unsigned i = 0; i < Count; ++i) {
    FieldDecl *Field =
        FieldDecl::Create(*this, CFConstantStringTagDecl, SourceLocation(),
                          SourceLocation(), &Idents.get(Fields[i].Name),
                          Fields[i].Type, /*TInfo=*/nullptr,
                          /*BitWidth=*/nullptr, /*Mutable=*/false, ICIS_NoInit);
    Field->setAccess(AS_public);
    CFConstantStringTagDecl->addDecl(Field);
  }
 
  CFConstantStringTagDecl->completeDefinition();
  // This type is designed to be compatible with NSConstantString, but cannot
  // use the same name, since NSConstantString is an interface.
  CanQualType tagType = getCanonicalTagType(CFConstantStringTagDecl);
  CFConstantStringTypeDecl =
      buildImplicitTypedef(tagType, "__NSConstantString");
 
  return CFConstantStringTypeDecl;
}
 
RecordDecl *ASTContext::getCFConstantStringTagDecl() const {
  if (!CFConstantStringTagDecl)
    getCFConstantStringDecl(); // Build the tag and the typedef.
  return CFConstantStringTagDecl;
}
 
// getCFConstantStringType - Return the type used for constant CFStrings.
QualType ASTContext::getCFConstantStringType() const {
  return getTypedefType(ElaboratedTypeKeyword::None, /*Qualifier=*/std::nullopt,
                        getCFConstantStringDecl());
}
 
QualType ASTContext::getObjCSuperType() const {
  if (ObjCSuperType.isNull()) {
    RecordDecl *ObjCSuperTypeDecl = buildImplicitRecord("objc_super");
    getTranslationUnitDecl()->addDecl(ObjCSuperTypeDecl);
    ObjCSuperType = getCanonicalTagType(ObjCSuperTypeDecl);
  }
  return ObjCSuperType;
}
 
void ASTContext::setCFConstantStringType(QualType T) {
  const auto *TT = T->castAs<TypedefType>();
  CFConstantStringTypeDecl = cast<TypedefDecl>(TT->getDecl());
  CFConstantStringTagDecl = TT->castAsRecordDecl();
}
 
QualType ASTContext::getBlockDescriptorType() const {
  if (BlockDescriptorType)
    return getCanonicalTagType(BlockDescriptorType);
 
  RecordDecl *RD;
  // FIXME: Needs the FlagAppleBlock bit.
  RD = buildImplicitRecord("__block_descriptor");
  RD->startDefinition();
 
  QualType FieldTypes[] = {
    UnsignedLongTy,
    UnsignedLongTy,
  };
 
  static const char *const FieldNames[] = {
    "reserved",
    "Size"
  };
 
  for (size_t i = 0; i < 2; ++i) {
    FieldDecl *Field = FieldDecl::Create(
        *this, RD, SourceLocation(), SourceLocation(),
        &Idents.get(FieldNames[i]), FieldTypes[i], /*TInfo=*/nullptr,
        /*BitWidth=*/nullptr, /*Mutable=*/false, ICIS_NoInit);
    Field->setAccess(AS_public);
    RD->addDecl(Field);
  }
 
  RD->completeDefinition();
 
  BlockDescriptorType = RD;
 
  return getCanonicalTagType(BlockDescriptorType);
}
 
QualType ASTContext::getBlockDescriptorExtendedType() const {
  if (BlockDescriptorExtendedType)
    return getCanonicalTagType(BlockDescriptorExtendedType);
 
  RecordDecl *RD;
  // FIXME: Needs the FlagAppleBlock bit.
  RD = buildImplicitRecord("__block_descriptor_withcopydispose");
  RD->startDefinition();
 
  QualType FieldTypes[] = {
    UnsignedLongTy,
    UnsignedLongTy,
    getPointerType(VoidPtrTy),
    getPointerType(VoidPtrTy)
  };
 
  static const char *const FieldNames[] = {
    "reserved",
    "Size",
    "CopyFuncPtr",
    "DestroyFuncPtr"
  };
 
  for (size_t i = 0; i < 4; ++i) {
    FieldDecl *Field = FieldDecl::Create(
        *this, RD, SourceLocation(), SourceLocation(),
        &Idents.get(FieldNames[i]), FieldTypes[i], /*TInfo=*/nullptr,
        /*BitWidth=*/nullptr,
        /*Mutable=*/false, ICIS_NoInit);
    Field->setAccess(AS_public);
    RD->addDecl(Field);
  }
 
  RD->completeDefinition();
 
  BlockDescriptorExtendedType = RD;
  return getCanonicalTagType(BlockDescriptorExtendedType);
}
 
OpenCLTypeKind ASTContext::getOpenCLTypeKind(const Type *T) const {
  const auto *BT = dyn_cast<BuiltinType>(T);
 
  if (!BT) {
    if (isa<PipeType>(T))
      return OCLTK_Pipe;
 
    return OCLTK_Default;
  }
 
  switch (BT->getKind()) {
#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix)                   \
  case BuiltinType::Id:                                                        \
    return OCLTK_Image;
#include "clang/Basic/OpenCLImageTypes.def"
 
  case BuiltinType::OCLClkEvent:
    return OCLTK_ClkEvent;
 
  case BuiltinType::OCLEvent:
    return OCLTK_Event;
 
  case BuiltinType::OCLQueue:
    return OCLTK_Queue;
 
  case BuiltinType::OCLReserveID:
    return OCLTK_ReserveID;
 
  case BuiltinType::OCLSampler:
    return OCLTK_Sampler;
 
  default:
    return OCLTK_Default;
  }
}
 
LangAS ASTContext::getOpenCLTypeAddrSpace(const Type *T) const {
  return Target->getOpenCLTypeAddrSpace(getOpenCLTypeKind(T));
}
 
/// BlockRequiresCopying - Returns true if byref variable "D" of type "Ty"
/// requires copy/dispose. Note that this must match the logic
/// in buildByrefHelpers.
bool ASTContext::BlockRequiresCopying(QualType Ty,
                                      const VarDecl *D) {
  if (const CXXRecordDecl *record = Ty->getAsCXXRecordDecl()) {
    const Expr *copyExpr = getBlockVarCopyInit(D).getCopyExpr();
    if (!copyExpr && record->hasTrivialDestructor()) return false;
 
    return true;
  }
 
  if (Ty.hasAddressDiscriminatedPointerAuth())
    return true;
 
  // The block needs copy/destroy helpers if Ty is non-trivial to destructively
  // move or destroy.
  if (Ty.isNonTrivialToPrimitiveDestructiveMove() || Ty.isDestructedType())
    return true;
 
  if (!Ty->isObjCRetainableType()) return false;
 
  Qualifiers qs = Ty.getQualifiers();
 
  // If we have lifetime, that dominates.
  if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) {
    switch (lifetime) {
      case Qualifiers::OCL_None: llvm_unreachable("impossible");
 
      // These are just bits as far as the runtime is concerned.
      case Qualifiers::OCL_ExplicitNone:
      case Qualifiers::OCL_Autoreleasing:
        return false;
 
      // These cases should have been taken care of when checking the type's
      // non-triviality.
      case Qualifiers::OCL_Weak:
      case Qualifiers::OCL_Strong:
        llvm_unreachable("impossible");
    }
    llvm_unreachable("fell out of lifetime switch!");
  }
  return (Ty->isBlockPointerType() || isObjCNSObjectType(Ty) ||
          Ty->isObjCObjectPointerType());
}
 
bool ASTContext::getByrefLifetime(QualType Ty,
                              Qualifiers::ObjCLifetime &LifeTime,
                              bool &HasByrefExtendedLayout) const {
  if (!getLangOpts().ObjC ||
      getLangOpts().getGC() != LangOptions::NonGC)
    return false;
 
  HasByrefExtendedLayout = false;
  if (Ty->isRecordType()) {
    HasByrefExtendedLayout = true;
    LifeTime = Qualifiers::OCL_None;
  } else if ((LifeTime = Ty.getObjCLifetime())) {
    // Honor the ARC qualifiers.
  } else if (Ty->isObjCObjectPointerType() || Ty->isBlockPointerType()) {
    // The MRR rule.
    LifeTime = Qualifiers::OCL_ExplicitNone;
  } else {
    LifeTime = Qualifiers::OCL_None;
  }
  return true;
}
 
CanQualType ASTContext::getNSUIntegerType() const {
  assert(Target && "Expected target to be initialized");
  const llvm::Triple &T = Target->getTriple();
  // Windows is LLP64 rather than LP64
  if (T.isOSWindows() && T.isArch64Bit())
    return UnsignedLongLongTy;
  return UnsignedLongTy;
}
 
CanQualType ASTContext::getNSIntegerType() const {
  assert(Target && "Expected target to be initialized");
  const llvm::Triple &T = Target->getTriple();
  // Windows is LLP64 rather than LP64
  if (T.isOSWindows() && T.isArch64Bit())
    return LongLongTy;
  return LongTy;
}
 
TypedefDecl *ASTContext::getObjCInstanceTypeDecl() {
  if (!ObjCInstanceTypeDecl)
    ObjCInstanceTypeDecl =
        buildImplicitTypedef(getObjCIdType(), "instancetype");
  return ObjCInstanceTypeDecl;
}
 
// This returns true if a type has been typedefed to BOOL:
// typedef <type> BOOL;
static bool isTypeTypedefedAsBOOL(QualType T) {
  if (const auto *TT = dyn_cast<TypedefType>(T))
    if (IdentifierInfo *II = TT->getDecl()->getIdentifier())
      return II->isStr("BOOL");
 
  return false;
}
 
/// getObjCEncodingTypeSize returns size of type for objective-c encoding
/// purpose.
CharUnits ASTContext::getObjCEncodingTypeSize(QualType type) const {
  if (!type->isIncompleteArrayType() && type->isIncompleteType())
    return CharUnits::Zero();
 
  CharUnits sz = getTypeSizeInChars(type);
 
  // Make all integer and enum types at least as large as an int
  if (sz.isPositive() && type->isIntegralOrEnumerationType())
    sz = std::max(sz, getTypeSizeInChars(IntTy));
  // Treat arrays as pointers, since that's how they're passed in.
  else if (type->isArrayType())
    sz = getTypeSizeInChars(VoidPtrTy);
  return sz;
}
 
bool ASTContext::isMSStaticDataMemberInlineDefinition(const VarDecl *VD) const {
  return getTargetInfo().getCXXABI().isMicrosoft() &&
         VD->isStaticDataMember() &&
         VD->getType()->isIntegralOrEnumerationType() &&
         !VD->getFirstDecl()->isOutOfLine() && VD->getFirstDecl()->hasInit();
}
 
ASTContext::InlineVariableDefinitionKind
ASTContext::getInlineVariableDefinitionKind(const VarDecl *VD) const {
  if (!VD->isInline())
    return InlineVariableDefinitionKind::None;
 
  // In almost all cases, it's a weak definition.
  auto *First = VD->getFirstDecl();
  if (First->isInlineSpecified() || !First->isStaticDataMember())
    return InlineVariableDefinitionKind::Weak;
 
  // If there's a file-context declaration in this translation unit, it's a
  // non-discardable definition.
  for (auto *D : VD->redecls())
    if (D->getLexicalDeclContext()->isFileContext() &&
        !D->isInlineSpecified() && (D->isConstexpr() || First->isConstexpr()))
      return InlineVariableDefinitionKind::Strong;
 
  // If we've not seen one yet, we don't know.
  return InlineVariableDefinitionKind::WeakUnknown;
}
 
static std::string charUnitsToString(const CharUnits &CU) {
  return llvm::itostr(CU.getQuantity());
}
 
/// getObjCEncodingForBlock - Return the encoded type for this block
/// declaration.
std::string ASTContext::getObjCEncodingForBlock(const BlockExpr *Expr) const {
  std::string S;
 
  const BlockDecl *Decl = Expr->getBlockDecl();
  QualType BlockTy =
      Expr->getType()->castAs<BlockPointerType>()->getPointeeType();
  QualType BlockReturnTy = BlockTy->castAs<FunctionType>()->getReturnType();
  // Encode result type.
  if (getLangOpts().EncodeExtendedBlockSig)
    getObjCEncodingForMethodParameter(Decl::OBJC_TQ_None, BlockReturnTy, S,
                                      true /*Extended*/);
  else
    getObjCEncodingForType(BlockReturnTy, S);
  // Compute size of all parameters.
  // Start with computing size of a pointer in number of bytes.
  // FIXME: There might(should) be a better way of doing this computation!
  CharUnits PtrSize = getTypeSizeInChars(VoidPtrTy);
  CharUnits ParmOffset = PtrSize;
  for (auto *PI : Decl->parameters()) {
    QualType PType = PI->getType();
    CharUnits sz = getObjCEncodingTypeSize(PType);
    if (sz.isZero())
      continue;
    assert(sz.isPositive() && "BlockExpr - Incomplete param type");
    ParmOffset += sz;
  }
  // Size of the argument frame
  S += charUnitsToString(ParmOffset);
  // Block pointer and offset.
  S += "@?0";
 
  // Argument types.
  ParmOffset = PtrSize;
  for (auto *PVDecl : Decl->parameters()) {
    QualType PType = PVDecl->getOriginalType();
    if (const auto *AT =
            dyn_cast<ArrayType>(PType->getCanonicalTypeInternal())) {
      // Use array's original type only if it has known number of
      // elements.
      if (!isa<ConstantArrayType>(AT))
        PType = PVDecl->getType();
    } else if (PType->isFunctionType())
      PType = PVDecl->getType();
    if (getLangOpts().EncodeExtendedBlockSig)
      getObjCEncodingForMethodParameter(Decl::OBJC_TQ_None, PType,
                                      S, true /*Extended*/);
    else
      getObjCEncodingForType(PType, S);
    S += charUnitsToString(ParmOffset);
    ParmOffset += getObjCEncodingTypeSize(PType);
  }
 
  return S;
}
 
std::string
ASTContext::getObjCEncodingForFunctionDecl(const FunctionDecl *Decl) const {
  std::string S;
  // Encode result type.
  getObjCEncodingForType(Decl->getReturnType(), S);
  CharUnits ParmOffset;
  // Compute size of all parameters.
  for (auto *PI : Decl->parameters()) {
    QualType PType = PI->getType();
    CharUnits sz = getObjCEncodingTypeSize(PType);
    if (sz.isZero())
      continue;
 
    assert(sz.isPositive() &&
           "getObjCEncodingForFunctionDecl - Incomplete param type");
    ParmOffset += sz;
  }
  S += charUnitsToString(ParmOffset);
  ParmOffset = CharUnits::Zero();
 
  // Argument types.
  for (auto *PVDecl : Decl->parameters()) {
    QualType PType = PVDecl->getOriginalType();
    if (const auto *AT =
            dyn_cast<ArrayType>(PType->getCanonicalTypeInternal())) {
      // Use array's original type only if it has known number of
      // elements.
      if (!isa<ConstantArrayType>(AT))
        PType = PVDecl->getType();
    } else if (PType->isFunctionType())
      PType = PVDecl->getType();
    getObjCEncodingForType(PType, S);
    S += charUnitsToString(ParmOffset);
    ParmOffset += getObjCEncodingTypeSize(PType);
  }
 
  return S;
}
 
/// getObjCEncodingForMethodParameter - Return the encoded type for a single
/// method parameter or return type. If Extended, include class names and
/// block object types.
void ASTContext::getObjCEncodingForMethodParameter(Decl::ObjCDeclQualifier QT,
                                                   QualType T, std::string& S,
                                                   bool Extended) const {
  // Encode type qualifier, 'in', 'inout', etc. for the parameter.
  getObjCEncodingForTypeQualifier(QT, S);
  // Encode parameter type.
  ObjCEncOptions Options = ObjCEncOptions()
                               .setExpandPointedToStructures()
                               .setExpandStructures()
                               .setIsOutermostType();
  if (Extended)
    Options.setEncodeBlockParameters().setEncodeClassNames();
  getObjCEncodingForTypeImpl(T, S, Options, /*Field=*/nullptr);
}
 
/// getObjCEncodingForMethodDecl - Return the encoded type for this method
/// declaration.
std::string ASTContext::getObjCEncodingForMethodDecl(const ObjCMethodDecl *Decl,
                                                     bool Extended) const {
  // FIXME: This is not very efficient.
  // Encode return type.
  std::string S;
  getObjCEncodingForMethodParameter(Decl->getObjCDeclQualifier(),
                                    Decl->getReturnType(), S, Extended);
  // Compute size of all parameters.
  // Start with computing size of a pointer in number of bytes.
  // FIXME: There might(should) be a better way of doing this computation!
  CharUnits PtrSize = getTypeSizeInChars(VoidPtrTy);
  // The first two arguments (self and _cmd) are pointers; account for
  // their size.
  CharUnits ParmOffset = 2 * PtrSize;
  for (ObjCMethodDecl::param_const_iterator PI = Decl->param_begin(),
       E = Decl->sel_param_end(); PI != E; ++PI) {
    QualType PType = (*PI)->getType();
    CharUnits sz = getObjCEncodingTypeSize(PType);
    if (sz.isZero())
      continue;
 
    assert(sz.isPositive() &&
           "getObjCEncodingForMethodDecl - Incomplete param type");
    ParmOffset += sz;
  }
  S += charUnitsToString(ParmOffset);
  S += "@0:";
  S += charUnitsToString(PtrSize);
 
  // Argument types.
  ParmOffset = 2 * PtrSize;
  for (ObjCMethodDecl::param_const_iterator PI = Decl->param_begin(),
       E = Decl->sel_param_end(); PI != E; ++PI) {
    const ParmVarDecl *PVDecl = *PI;
    QualType PType = PVDecl->getOriginalType();
    if (const auto *AT =
            dyn_cast<ArrayType>(PType->getCanonicalTypeInternal())) {
      // Use array's original type only if it has known number of
      // elements.
      if (!isa<ConstantArrayType>(AT))
        PType = PVDecl->getType();
    } else if (PType->isFunctionType())
      PType = PVDecl->getType();
    getObjCEncodingForMethodParameter(PVDecl->getObjCDeclQualifier(),
                                      PType, S, Extended);
    S += charUnitsToString(ParmOffset);
    ParmOffset += getObjCEncodingTypeSize(PType);
  }
 
  return S;
}
 
ObjCPropertyImplDecl *
ASTContext::getObjCPropertyImplDeclForPropertyDecl(
                                      const ObjCPropertyDecl *PD,
                                      const Decl *Container) const {
  if (!Container)
    return nullptr;
  if (const auto *CID = dyn_cast<ObjCCategoryImplDecl>(Container)) {
    for (auto *PID : CID->property_impls())
      if (PID->getPropertyDecl() == PD)
        return PID;
  } else {
    const auto *OID = cast<ObjCImplementationDecl>(Container);
    for (auto *PID : OID->property_impls())
      if (PID->getPropertyDecl() == PD)
        return PID;
  }
  return nullptr;
}
 
/// getObjCEncodingForPropertyDecl - Return the encoded type for this
/// property declaration. If non-NULL, Container must be either an
/// ObjCCategoryImplDecl or ObjCImplementationDecl; it should only be
/// NULL when getting encodings for protocol properties.
/// Property attributes are stored as a comma-delimited C string. The simple
/// attributes readonly and bycopy are encoded as single characters. The
/// parametrized attributes, getter=name, setter=name, and ivar=name, are
/// encoded as single characters, followed by an identifier. Property types
/// are also encoded as a parametrized attribute. The characters used to encode
/// these attributes are defined by the following enumeration:
/// @code
/// enum PropertyAttributes {
/// kPropertyReadOnly = 'R',   // property is read-only.
/// kPropertyBycopy = 'C',     // property is a copy of the value last assigned
/// kPropertyByref = '&',  // property is a reference to the value last assigned
/// kPropertyDynamic = 'D',    // property is dynamic
/// kPropertyGetter = 'G',     // followed by getter selector name
/// kPropertySetter = 'S',     // followed by setter selector name
/// kPropertyInstanceVariable = 'V'  // followed by instance variable  name
/// kPropertyType = 'T'              // followed by old-style type encoding.
/// kPropertyWeak = 'W'              // 'weak' property
/// kPropertyStrong = 'P'            // property GC'able
/// kPropertyNonAtomic = 'N'         // property non-atomic
/// kPropertyOptional = '?'          // property optional
/// };
/// @endcode
std::string
ASTContext::getObjCEncodingForPropertyDecl(const ObjCPropertyDecl *PD,
                                           const Decl *Container) const {
  // Collect information from the property implementation decl(s).
  bool Dynamic = false;
  ObjCPropertyImplDecl *SynthesizePID = nullptr;
 
  if (ObjCPropertyImplDecl *PropertyImpDecl =
      getObjCPropertyImplDeclForPropertyDecl(PD, Container)) {
    if (PropertyImpDecl->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
      Dynamic = true;
    else
      SynthesizePID = PropertyImpDecl;
  }
 
  // FIXME: This is not very efficient.
  std::string S = "T";
 
  // Encode result type.
  // GCC has some special rules regarding encoding of properties which
  // closely resembles encoding of ivars.
  getObjCEncodingForPropertyType(PD->getType(), S);
 
  if (PD->isOptional())
    S += ",?";
 
  if (PD->isReadOnly()) {
    S += ",R";
    if (PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_copy)
      S += ",C";
    if (PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_retain)
      S += ",&";
    if (PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_weak)
      S += ",W";
  } else {
    switch (PD->getSetterKind()) {
    case ObjCPropertyDecl::Assign: break;
    case ObjCPropertyDecl::Copy:   S += ",C"; break;
    case ObjCPropertyDecl::Retain: S += ",&"; break;
    case ObjCPropertyDecl::Weak:   S += ",W"; break;
    }
  }
 
  // It really isn't clear at all what this means, since properties
  // are "dynamic by default".
  if (Dynamic)
    S += ",D";
 
  if (PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_nonatomic)
    S += ",N";
 
  if (PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_getter) {
    S += ",G";
    S += PD->getGetterName().getAsString();
  }
 
  if (PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_setter) {
    S += ",S";
    S += PD->getSetterName().getAsString();
  }
 
  if (SynthesizePID) {
    const ObjCIvarDecl *OID = SynthesizePID->getPropertyIvarDecl();
    S += ",V";
    S += OID->getNameAsString();
  }
 
  // FIXME: OBJCGC: weak & strong
  return S;
}
 
/// getLegacyIntegralTypeEncoding -
/// Another legacy compatibility encoding: 32-bit longs are encoded as
/// 'l' or 'L' , but not always.  For typedefs, we need to use
/// 'i' or 'I' instead if encoding a struct field, or a pointer!
void ASTContext::getLegacyIntegralTypeEncoding (QualType &PointeeTy) const {
  if (PointeeTy->getAs<TypedefType>()) {
    if (const auto *BT = PointeeTy->getAs<BuiltinType>()) {
      if (BT->getKind() == BuiltinType::ULong && getIntWidth(PointeeTy) == 32)
        PointeeTy = UnsignedIntTy;
      else
        if (BT->getKind() == BuiltinType::Long && getIntWidth(PointeeTy) == 32)
          PointeeTy = IntTy;
    }
  }
}
 
void ASTContext::getObjCEncodingForType(QualType T, std::string& S,
                                        const FieldDecl *Field,
                                        QualType *NotEncodedT) const {
  // We follow the behavior of gcc, expanding structures which are
  // directly pointed to, and expanding embedded structures. Note that
  // these rules are sufficient to prevent recursive encoding of the
  // same type.
  getObjCEncodingForTypeImpl(T, S,
                             ObjCEncOptions()
                                 .setExpandPointedToStructures()
                                 .setExpandStructures()
                                 .setIsOutermostType(),
                             Field, NotEncodedT);
}
 
void ASTContext::getObjCEncodingForPropertyType(QualType T,
                                                std::string& S) const {
  // Encode result type.
  // GCC has some special rules regarding encoding of properties which
  // closely resembles encoding of ivars.
  getObjCEncodingForTypeImpl(T, S,
                             ObjCEncOptions()
                                 .setExpandPointedToStructures()
                                 .setExpandStructures()
                                 .setIsOutermostType()
                                 .setEncodingProperty(),
                             /*Field=*/nullptr);
}
 
static char getObjCEncodingForPrimitiveType(const ASTContext *C,
                                            const BuiltinType *BT) {
    BuiltinType::Kind kind = BT->getKind();
    switch (kind) {
    case BuiltinType::Void:       return 'v';
    case BuiltinType::Bool:       return 'B';
    case BuiltinType::Char8:
    case BuiltinType::Char_U:
    case BuiltinType::UChar:      return 'C';
    case BuiltinType::Char16:
    case BuiltinType::UShort:     return 'S';
    case BuiltinType::Char32:
    case BuiltinType::UInt:       return 'I';
    case BuiltinType::ULong:
        return C->getTargetInfo().getLongWidth() == 32 ? 'L' : 'Q';
    case BuiltinType::UInt128:    return 'T';
    case BuiltinType::ULongLong:  return 'Q';
    case BuiltinType::Char_S:
    case BuiltinType::SChar:      return 'c';
    case BuiltinType::Short:      return 's';
    case BuiltinType::WChar_S:
    case BuiltinType::WChar_U:
    case BuiltinType::Int:        return 'i';
    case BuiltinType::Long:
      return C->getTargetInfo().getLongWidth() == 32 ? 'l' : 'q';
    case BuiltinType::LongLong:   return 'q';
    case BuiltinType::Int128:     return 't';
    case BuiltinType::Float:      return 'f';
    case BuiltinType::Double:     return 'd';
    case BuiltinType::LongDouble: return 'D';
    case BuiltinType::NullPtr:    return '*'; // like char*
 
    case BuiltinType::BFloat16:
    case BuiltinType::Float16:
    case BuiltinType::Float128:
    case BuiltinType::Ibm128:
    case BuiltinType::Half:
    case BuiltinType::ShortAccum:
    case BuiltinType::Accum:
    case BuiltinType::LongAccum:
    case BuiltinType::UShortAccum:
    case BuiltinType::UAccum:
    case BuiltinType::ULongAccum:
    case BuiltinType::ShortFract:
    case BuiltinType::Fract:
    case BuiltinType::LongFract:
    case BuiltinType::UShortFract:
    case BuiltinType::UFract:
    case BuiltinType::ULongFract:
    case BuiltinType::SatShortAccum:
    case BuiltinType::SatAccum:
    case BuiltinType::SatLongAccum:
    case BuiltinType::SatUShortAccum:
    case BuiltinType::SatUAccum:
    case BuiltinType::SatULongAccum:
    case BuiltinType::SatShortFract:
    case BuiltinType::SatFract:
    case BuiltinType::SatLongFract:
    case BuiltinType::SatUShortFract:
    case BuiltinType::SatUFract:
    case BuiltinType::SatULongFract:
      // FIXME: potentially need @encodes for these!
      return ' ';
 
#define SVE_TYPE(Name, Id, SingletonId) \
    case BuiltinType::Id:
#include "clang/Basic/AArch64ACLETypes.def"
#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
#include "clang/Basic/RISCVVTypes.def"
#define WASM_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
#include "clang/Basic/WebAssemblyReferenceTypes.def"
#define AMDGPU_TYPE(Name, Id, SingletonId, Width, Align) case BuiltinType::Id:
#include "clang/Basic/AMDGPUTypes.def"
      {
        DiagnosticsEngine &Diags = C->getDiagnostics();
        unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
                                                "cannot yet @encode type %0");
        Diags.Report(DiagID) << BT->getName(C->getPrintingPolicy());
        return ' ';
      }
 
    case BuiltinType::ObjCId:
    case BuiltinType::ObjCClass:
    case BuiltinType::ObjCSel:
      llvm_unreachable("@encoding ObjC primitive type");
 
    // OpenCL and placeholder types don't need @encodings.
#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"
    case BuiltinType::OCLEvent:
    case BuiltinType::OCLClkEvent:
    case BuiltinType::OCLQueue:
    case BuiltinType::OCLReserveID:
    case BuiltinType::OCLSampler:
    case BuiltinType::Dependent:
#define PPC_VECTOR_TYPE(Name, Id, Size) \
    case BuiltinType::Id:
#include "clang/Basic/PPCTypes.def"
#define HLSL_INTANGIBLE_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
#include "clang/Basic/HLSLIntangibleTypes.def"
#define BUILTIN_TYPE(KIND, ID)
#define PLACEHOLDER_TYPE(KIND, ID) \
    case BuiltinType::KIND:
#include "clang/AST/BuiltinTypes.def"
      llvm_unreachable("invalid builtin type for @encode");
    }
    llvm_unreachable("invalid BuiltinType::Kind value");
}
 
static char ObjCEncodingForEnumDecl(const ASTContext *C, const EnumDecl *ED) {
  EnumDecl *Enum = ED->getDefinitionOrSelf();
 
  // The encoding of an non-fixed enum type is always 'i', regardless of size.
  if (!Enum->isFixed())
    return 'i';
 
  // The encoding of a fixed enum type matches its fixed underlying type.
  const auto *BT = Enum->getIntegerType()->castAs<BuiltinType>();
  return getObjCEncodingForPrimitiveType(C, BT);
}
 
static void EncodeBitField(const ASTContext *Ctx, std::string& S,
                           QualType T, const FieldDecl *FD) {
  assert(FD->isBitField() && "not a bitfield - getObjCEncodingForTypeImpl");
  S += 'b';
  // The NeXT runtime encodes bit fields as b followed by the number of bits.
  // The GNU runtime requires more information; bitfields are encoded as b,
  // then the offset (in bits) of the first element, then the type of the
  // bitfield, then the size in bits.  For example, in this structure:
  //
  // struct
  // {
  //    int integer;
  //    int flags:2;
  // };
  // On a 32-bit system, the encoding for flags would be b2 for the NeXT
  // runtime, but b32i2 for the GNU runtime.  The reason for this extra
  // information is not especially sensible, but we're stuck with it for
  // compatibility with GCC, although providing it breaks anything that
  // actually uses runtime introspection and wants to work on both runtimes...
  if (Ctx->getLangOpts().ObjCRuntime.isGNUFamily()) {
    uint64_t Offset;
 
    if (const auto *IVD = dyn_cast<ObjCIvarDecl>(FD)) {
      Offset = Ctx->lookupFieldBitOffset(IVD->getContainingInterface(), IVD);
    } else {
      const RecordDecl *RD = FD->getParent();
      const ASTRecordLayout &RL = Ctx->getASTRecordLayout(RD);
      Offset = RL.getFieldOffset(FD->getFieldIndex());
    }
 
    S += llvm::utostr(Offset);
 
    if (const auto *ET = T->getAsCanonical<EnumType>())
      S += ObjCEncodingForEnumDecl(Ctx, ET->getDecl());
    else {
      const auto *BT = T->castAs<BuiltinType>();
      S += getObjCEncodingForPrimitiveType(Ctx, BT);
    }
  }
  S += llvm::utostr(FD->getBitWidthValue());
}
 
// Helper function for determining whether the encoded type string would include
// a template specialization type.
static bool hasTemplateSpecializationInEncodedString(const Type *T,
                                                     bool VisitBasesAndFields) {
  T = T->getBaseElementTypeUnsafe();
 
  if (auto *PT = T->getAs<PointerType>())
    return hasTemplateSpecializationInEncodedString(
        PT->getPointeeType().getTypePtr(), false);
 
  auto *CXXRD = T->getAsCXXRecordDecl();
 
  if (!CXXRD)
    return false;
 
  if (isa<ClassTemplateSpecializationDecl>(CXXRD))
    return true;
 
  if (!CXXRD->hasDefinition() || !VisitBasesAndFields)
    return false;
 
  for (const auto &B : CXXRD->bases())
    if (hasTemplateSpecializationInEncodedString(B.getType().getTypePtr(),
                                                 true))
      return true;
 
  for (auto *FD : CXXRD->fields())
    if (hasTemplateSpecializationInEncodedString(FD->getType().getTypePtr(),
                                                 true))
      return true;
 
  return false;
}
 
// FIXME: Use SmallString for accumulating string.
void ASTContext::getObjCEncodingForTypeImpl(QualType T, std::string &S,
                                            const ObjCEncOptions Options,
                                            const FieldDecl *FD,
                                            QualType *NotEncodedT) const {
  CanQualType CT = getCanonicalType(T);
  switch (CT->getTypeClass()) {
  case Type::Builtin:
  case Type::Enum:
    if (FD && FD->isBitField())
      return EncodeBitField(this, S, T, FD);
    if (const auto *BT = dyn_cast<BuiltinType>(CT))
      S += getObjCEncodingForPrimitiveType(this, BT);
    else
      S += ObjCEncodingForEnumDecl(this, cast<EnumType>(CT)->getDecl());
    return;
 
  case Type::Complex:
    S += 'j';
    getObjCEncodingForTypeImpl(T->castAs<ComplexType>()->getElementType(), S,
                               ObjCEncOptions(),
                               /*Field=*/nullptr);
    return;
 
  case Type::Atomic:
    S += 'A';
    getObjCEncodingForTypeImpl(T->castAs<AtomicType>()->getValueType(), S,
                               ObjCEncOptions(),
                               /*Field=*/nullptr);
    return;
 
  // encoding for pointer or reference types.
  case Type::Pointer:
  case Type::LValueReference:
  case Type::RValueReference: {
    QualType PointeeTy;
    if (isa<PointerType>(CT)) {
      const auto *PT = T->castAs<PointerType>();
      if (PT->isObjCSelType()) {
        S += ':';
        return;
      }
      PointeeTy = PT->getPointeeType();
    } else {
      PointeeTy = T->castAs<ReferenceType>()->getPointeeType();
    }
 
    bool isReadOnly = false;
    // For historical/compatibility reasons, the read-only qualifier of the
    // pointee gets emitted _before_ the '^'.  The read-only qualifier of
    // the pointer itself gets ignored, _unless_ we are looking at a typedef!
    // Also, do not emit the 'r' for anything but the outermost type!
    if (T->getAs<TypedefType>()) {
      if (Options.IsOutermostType() && T.isConstQualified()) {
        isReadOnly = true;
        S += 'r';
      }
    } else if (Options.IsOutermostType()) {
      QualType P = PointeeTy;
      while (auto PT = P->getAs<PointerType>())
        P = PT->getPointeeType();
      if (P.isConstQualified()) {
        isReadOnly = true;
        S += 'r';
      }
    }
    if (isReadOnly) {
      // Another legacy compatibility encoding. Some ObjC qualifier and type
      // combinations need to be rearranged.
      // Rewrite "in const" from "nr" to "rn"
      if (StringRef(S).ends_with("nr"))
        S.replace(S.end()-2, S.end(), "rn");
    }
 
    if (PointeeTy->isCharType()) {
      // char pointer types should be encoded as '*' unless it is a
      // type that has been typedef'd to 'BOOL'.
      if (!isTypeTypedefedAsBOOL(PointeeTy)) {
        S += '*';
        return;
      }
    } else if (const auto *RTy = PointeeTy->getAsCanonical<RecordType>()) {
      const IdentifierInfo *II = RTy->getDecl()->getIdentifier();
      // GCC binary compat: Need to convert "struct objc_class *" to "#".
      if (II == &Idents.get("objc_class")) {
        S += '#';
        return;
      }
      // GCC binary compat: Need to convert "struct objc_object *" to "@".
      if (II == &Idents.get("objc_object")) {
        S += '@';
        return;
      }
      // If the encoded string for the class includes template names, just emit
      // "^v" for pointers to the class.
      if (getLangOpts().CPlusPlus &&
          (!getLangOpts().EncodeCXXClassTemplateSpec &&
           hasTemplateSpecializationInEncodedString(
               RTy, Options.ExpandPointedToStructures()))) {
        S += "^v";
        return;
      }
      // fall through...
    }
    S += '^';
    getLegacyIntegralTypeEncoding(PointeeTy);
 
    ObjCEncOptions NewOptions;
    if (Options.ExpandPointedToStructures())
      NewOptions.setExpandStructures();
    getObjCEncodingForTypeImpl(PointeeTy, S, NewOptions,
                               /*Field=*/nullptr, NotEncodedT);
    return;
  }
 
  case Type::ConstantArray:
  case Type::IncompleteArray:
  case Type::VariableArray: {
    const auto *AT = cast<ArrayType>(CT);
 
    if (isa<IncompleteArrayType>(AT) && !Options.IsStructField()) {
      // Incomplete arrays are encoded as a pointer to the array element.
      S += '^';
 
      getObjCEncodingForTypeImpl(
          AT->getElementType(), S,
          Options.keepingOnly(ObjCEncOptions().setExpandStructures()), FD);
    } else {
      S += '[';
 
      if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
        S += llvm::utostr(CAT->getZExtSize());
      else {
        //Variable length arrays are encoded as a regular array with 0 elements.
        assert((isa<VariableArrayType>(AT) || isa<IncompleteArrayType>(AT)) &&
               "Unknown array type!");
        S += '0';
      }
 
      getObjCEncodingForTypeImpl(
          AT->getElementType(), S,
          Options.keepingOnly(ObjCEncOptions().setExpandStructures()), FD,
          NotEncodedT);
      S += ']';
    }
    return;
  }
 
  case Type::FunctionNoProto:
  case Type::FunctionProto:
    S += '?';
    return;
 
  case Type::Record: {
    RecordDecl *RDecl = cast<RecordType>(CT)->getDecl();
    S += RDecl->isUnion() ? '(' : '{';
    // Anonymous structures print as '?'
    if (const IdentifierInfo *II = RDecl->getIdentifier()) {
      S += II->getName();
      if (const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(RDecl)) {
        const TemplateArgumentList &TemplateArgs = Spec->getTemplateArgs();
        llvm::raw_string_ostream OS(S);
        printTemplateArgumentList(OS, TemplateArgs.asArray(),
                                  getPrintingPolicy());
      }
    } else {
      S += '?';
    }
    if (Options.ExpandStructures()) {
      S += '=';
      if (!RDecl->isUnion()) {
        getObjCEncodingForStructureImpl(RDecl, S, FD, true, NotEncodedT);
      } else {
        for (const auto *Field : RDecl->fields()) {
          if (FD) {
            S += '"';
            S += Field->getNameAsString();
            S += '"';
          }
 
          // Special case bit-fields.
          if (Field->isBitField()) {
            getObjCEncodingForTypeImpl(Field->getType(), S,
                                       ObjCEncOptions().setExpandStructures(),
                                       Field);
          } else {
            QualType qt = Field->getType();
            getLegacyIntegralTypeEncoding(qt);
            getObjCEncodingForTypeImpl(
                qt, S,
                ObjCEncOptions().setExpandStructures().setIsStructField(), FD,
                NotEncodedT);
          }
        }
      }
    }
    S += RDecl->isUnion() ? ')' : '}';
    return;
  }
 
  case Type::BlockPointer: {
    const auto *BT = T->castAs<BlockPointerType>();
    S += "@?"; // Unlike a pointer-to-function, which is "^?".
    if (Options.EncodeBlockParameters()) {
      const auto *FT = BT->getPointeeType()->castAs<FunctionType>();
 
      S += '<';
      // Block return type
      getObjCEncodingForTypeImpl(FT->getReturnType(), S,
                                 Options.forComponentType(), FD, NotEncodedT);
      // Block self
      S += "@?";
      // Block parameters
      if (const auto *FPT = dyn_cast<FunctionProtoType>(FT)) {
        for (const auto &I : FPT->param_types())
          getObjCEncodingForTypeImpl(I, S, Options.forComponentType(), FD,
                                     NotEncodedT);
      }
      S += '>';
    }
    return;
  }
 
  case Type::ObjCObject: {
    // hack to match legacy encoding of *id and *Class
    QualType Ty = getObjCObjectPointerType(CT);
    if (Ty->isObjCIdType()) {
      S += "{objc_object=}";
      return;
    }
    else if (Ty->isObjCClassType()) {
      S += "{objc_class=}";
      return;
    }
    // TODO: Double check to make sure this intentionally falls through.
    [[fallthrough]];
  }
 
  case Type::ObjCInterface: {
    // Ignore protocol qualifiers when mangling at this level.
    // @encode(class_name)
    ObjCInterfaceDecl *OI = T->castAs<ObjCObjectType>()->getInterface();
    S += '{';
    S += OI->getObjCRuntimeNameAsString();
    if (Options.ExpandStructures()) {
      S += '=';
      SmallVector<const ObjCIvarDecl*, 32> Ivars;
      DeepCollectObjCIvars(OI, true, Ivars);
      for (unsigned i = 0, e = Ivars.size(); i != e; ++i) {
        const FieldDecl *Field = Ivars[i];
        if (Field->isBitField())
          getObjCEncodingForTypeImpl(Field->getType(), S,
                                     ObjCEncOptions().setExpandStructures(),
                                     Field);
        else
          getObjCEncodingForTypeImpl(Field->getType(), S,
                                     ObjCEncOptions().setExpandStructures(), FD,
                                     NotEncodedT);
      }
    }
    S += '}';
    return;
  }
 
  case Type::ObjCObjectPointer: {
    const auto *OPT = T->castAs<ObjCObjectPointerType>();
    if (OPT->isObjCIdType()) {
      S += '@';
      return;
    }
 
    if (OPT->isObjCClassType() || OPT->isObjCQualifiedClassType()) {
      // FIXME: Consider if we need to output qualifiers for 'Class<p>'.
      // Since this is a binary compatibility issue, need to consult with
      // runtime folks. Fortunately, this is a *very* obscure construct.
      S += '#';
      return;
    }
 
    if (OPT->isObjCQualifiedIdType()) {
      getObjCEncodingForTypeImpl(
          getObjCIdType(), S,
          Options.keepingOnly(ObjCEncOptions()
                                  .setExpandPointedToStructures()
                                  .setExpandStructures()),
          FD);
      if (FD || Options.EncodingProperty() || Options.EncodeClassNames()) {
        // Note that we do extended encoding of protocol qualifier list
        // Only when doing ivar or property encoding.
        S += '"';
        for (const auto *I : OPT->quals()) {
          S += '<';
          S += I->getObjCRuntimeNameAsString();
          S += '>';
        }
        S += '"';
      }
      return;
    }
 
    S += '@';
    if (OPT->getInterfaceDecl() &&
        (FD || Options.EncodingProperty() || Options.EncodeClassNames())) {
      S += '"';
      S += OPT->getInterfaceDecl()->getObjCRuntimeNameAsString();
      for (const auto *I : OPT->quals()) {
        S += '<';
        S += I->getObjCRuntimeNameAsString();
        S += '>';
      }
      S += '"';
    }
    return;
  }
 
  // gcc just blithely ignores member pointers.
  // FIXME: we should do better than that.  'M' is available.
  case Type::MemberPointer:
  // This matches gcc's encoding, even though technically it is insufficient.
  //FIXME. We should do a better job than gcc.
  case Type::Vector:
  case Type::ExtVector:
  // Until we have a coherent encoding of these three types, issue warning.
    if (NotEncodedT)
      *NotEncodedT = T;
    return;
 
  case Type::ConstantMatrix:
    if (NotEncodedT)
      *NotEncodedT = T;
    return;
 
  case Type::BitInt:
    if (NotEncodedT)
      *NotEncodedT = T;
    return;
 
  // We could see an undeduced auto type here during error recovery.
  // Just ignore it.
  case Type::Auto:
  case Type::DeducedTemplateSpecialization:
    return;
 
  case Type::HLSLAttributedResource:
  case Type::HLSLInlineSpirv:
    llvm_unreachable("unexpected type");
 
  case Type::ArrayParameter:
  case Type::Pipe:
#define ABSTRACT_TYPE(KIND, BASE)
#define TYPE(KIND, BASE)
#define DEPENDENT_TYPE(KIND, BASE) \
  case Type::KIND:
#define NON_CANONICAL_TYPE(KIND, BASE) \
  case Type::KIND:
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(KIND, BASE) \
  case Type::KIND:
#include "clang/AST/TypeNodes.inc"
    llvm_unreachable("@encode for dependent type!");
  }
  llvm_unreachable("bad type kind!");
}
 
void ASTContext::getObjCEncodingForStructureImpl(RecordDecl *RDecl,
                                                 std::string &S,
                                                 const FieldDecl *FD,
                                                 bool includeVBases,
                                                 QualType *NotEncodedT) const {
  assert(RDecl && "Expected non-null RecordDecl");
  assert(!RDecl->isUnion() && "Should not be called for unions");
  if (!RDecl->getDefinition() || RDecl->getDefinition()->isInvalidDecl())
    return;
 
  const auto *CXXRec = dyn_cast<CXXRecordDecl>(RDecl);
  std::multimap<uint64_t, NamedDecl *> FieldOrBaseOffsets;
  const ASTRecordLayout &layout = getASTRecordLayout(RDecl);
 
  if (CXXRec) {
    for (const auto &BI : CXXRec->bases()) {
      if (!BI.isVirtual()) {
        CXXRecordDecl *base = BI.getType()->getAsCXXRecordDecl();
        if (base->isEmpty())
          continue;
        uint64_t offs = toBits(layout.getBaseClassOffset(base));
        FieldOrBaseOffsets.insert(FieldOrBaseOffsets.upper_bound(offs),
                                  std::make_pair(offs, base));
      }
    }
  }
 
  for (FieldDecl *Field : RDecl->fields()) {
    if (!Field->isZeroLengthBitField() && Field->isZeroSize(*this))
      continue;
    uint64_t offs = layout.getFieldOffset(Field->getFieldIndex());
    FieldOrBaseOffsets.insert(FieldOrBaseOffsets.upper_bound(offs),
                              std::make_pair(offs, Field));
  }
 
  if (CXXRec && includeVBases) {
    for (const auto &BI : CXXRec->vbases()) {
      CXXRecordDecl *base = BI.getType()->getAsCXXRecordDecl();
      if (base->isEmpty())
        continue;
      uint64_t offs = toBits(layout.getVBaseClassOffset(base));
      if (offs >= uint64_t(toBits(layout.getNonVirtualSize())) &&
          FieldOrBaseOffsets.find(offs) == FieldOrBaseOffsets.end())
        FieldOrBaseOffsets.insert(FieldOrBaseOffsets.end(),
                                  std::make_pair(offs, base));
    }
  }
 
  CharUnits size;
  if (CXXRec) {
    size = includeVBases ? layout.getSize() : layout.getNonVirtualSize();
  } else {
    size = layout.getSize();
  }
 
#ifndef NDEBUG
  uint64_t CurOffs = 0;
#endif
  std::multimap<uint64_t, NamedDecl *>::iterator
    CurLayObj = FieldOrBaseOffsets.begin();
 
  if (CXXRec && CXXRec->isDynamicClass() &&
      (CurLayObj == FieldOrBaseOffsets.end() || CurLayObj->first != 0)) {
    if (FD) {
      S += "\"_vptr$";
      std::string recname = CXXRec->getNameAsString();
      if (recname.empty()) recname = "?";
      S += recname;
      S += '"';
    }
    S += "^^?";
#ifndef NDEBUG
    CurOffs += getTypeSize(VoidPtrTy);
#endif
  }
 
  if (!RDecl->hasFlexibleArrayMember()) {
    // Mark the end of the structure.
    uint64_t offs = toBits(size);
    FieldOrBaseOffsets.insert(FieldOrBaseOffsets.upper_bound(offs),
                              std::make_pair(offs, nullptr));
  }
 
  for (; CurLayObj != FieldOrBaseOffsets.end(); ++CurLayObj) {
#ifndef NDEBUG
    assert(CurOffs <= CurLayObj->first);
    if (CurOffs < CurLayObj->first) {
      uint64_t padding = CurLayObj->first - CurOffs;
      // FIXME: There doesn't seem to be a way to indicate in the encoding that
      // packing/alignment of members is different that normal, in which case
      // the encoding will be out-of-sync with the real layout.
      // If the runtime switches to just consider the size of types without
      // taking into account alignment, we could make padding explicit in the
      // encoding (e.g. using arrays of chars). The encoding strings would be
      // longer then though.
      CurOffs += padding;
    }
#endif
 
    NamedDecl *dcl = CurLayObj->second;
    if (!dcl)
      break; // reached end of structure.
 
    if (auto *base = dyn_cast<CXXRecordDecl>(dcl)) {
      // We expand the bases without their virtual bases since those are going
      // in the initial structure. Note that this differs from gcc which
      // expands virtual bases each time one is encountered in the hierarchy,
      // making the encoding type bigger than it really is.
      getObjCEncodingForStructureImpl(base, S, FD, /*includeVBases*/false,
                                      NotEncodedT);
      assert(!base->isEmpty());
#ifndef NDEBUG
      CurOffs += toBits(getASTRecordLayout(base).getNonVirtualSize());
#endif
    } else {
      const auto *field = cast<FieldDecl>(dcl);
      if (FD) {
        S += '"';
        S += field->getNameAsString();
        S += '"';
      }
 
      if (field->isBitField()) {
        EncodeBitField(this, S, field->getType(), field);
#ifndef NDEBUG
        CurOffs += field->getBitWidthValue();
#endif
      } else {
        QualType qt = field->getType();
        getLegacyIntegralTypeEncoding(qt);
        getObjCEncodingForTypeImpl(
            qt, S, ObjCEncOptions().setExpandStructures().setIsStructField(),
            FD, NotEncodedT);
#ifndef NDEBUG
        CurOffs += getTypeSize(field->getType());
#endif
      }
    }
  }
}
 
void ASTContext::getObjCEncodingForTypeQualifier(Decl::ObjCDeclQualifier QT,
                                                 std::string& S) const {
  if (QT & Decl::OBJC_TQ_In)
    S += 'n';
  if (QT & Decl::OBJC_TQ_Inout)
    S += 'N';
  if (QT & Decl::OBJC_TQ_Out)
    S += 'o';
  if (QT & Decl::OBJC_TQ_Bycopy)
    S += 'O';
  if (QT & Decl::OBJC_TQ_Byref)
    S += 'R';
  if (QT & Decl::OBJC_TQ_Oneway)
    S += 'V';
}
 
TypedefDecl *ASTContext::getObjCIdDecl() const {
  if (!ObjCIdDecl) {
    QualType T = getObjCObjectType(ObjCBuiltinIdTy, {}, {});
    T = getObjCObjectPointerType(T);
    ObjCIdDecl = buildImplicitTypedef(T, "id");
  }
  return ObjCIdDecl;
}
 
TypedefDecl *ASTContext::getObjCSelDecl() const {
  if (!ObjCSelDecl) {
    QualType T = getPointerType(ObjCBuiltinSelTy);
    ObjCSelDecl = buildImplicitTypedef(T, "SEL");
  }
  return ObjCSelDecl;
}
 
TypedefDecl *ASTContext::getObjCClassDecl() const {
  if (!ObjCClassDecl) {
    QualType T = getObjCObjectType(ObjCBuiltinClassTy, {}, {});
    T = getObjCObjectPointerType(T);
    ObjCClassDecl = buildImplicitTypedef(T, "Class");
  }
  return ObjCClassDecl;
}
 
ObjCInterfaceDecl *ASTContext::getObjCProtocolDecl() const {
  if (!ObjCProtocolClassDecl) {
    ObjCProtocolClassDecl
      = ObjCInterfaceDecl::Create(*this, getTranslationUnitDecl(),
                                  SourceLocation(),
                                  &Idents.get("Protocol"),
                                  /*typeParamList=*/nullptr,
                                  /*PrevDecl=*/nullptr,
                                  SourceLocation(), true);
  }
 
  return ObjCProtocolClassDecl;
}
 
PointerAuthQualifier ASTContext::getObjCMemberSelTypePtrAuth() {
  if (!getLangOpts().PointerAuthObjcInterfaceSel)
    return PointerAuthQualifier();
  return PointerAuthQualifier::Create(
      getLangOpts().PointerAuthObjcInterfaceSelKey,
      /*isAddressDiscriminated=*/true, SelPointerConstantDiscriminator,
      PointerAuthenticationMode::SignAndAuth,
      /*isIsaPointer=*/false,
      /*authenticatesNullValues=*/false);
}
 
//===----------------------------------------------------------------------===//
// __builtin_va_list Construction Functions
//===----------------------------------------------------------------------===//
 
static TypedefDecl *CreateCharPtrNamedVaListDecl(const ASTContext *Context,
                                                 StringRef Name) {
  // typedef char* __builtin[_ms]_va_list;
  QualType T = Context->getPointerType(Context->CharTy);
  return Context->buildImplicitTypedef(T, Name);
}
 
static TypedefDecl *CreateMSVaListDecl(const ASTContext *Context) {
  return CreateCharPtrNamedVaListDecl(Context, "__builtin_ms_va_list");
}
 
static TypedefDecl *CreateCharPtrBuiltinVaListDecl(const ASTContext *Context) {
  return CreateCharPtrNamedVaListDecl(Context, "__builtin_va_list");
}
 
static TypedefDecl *CreateVoidPtrBuiltinVaListDecl(const ASTContext *Context) {
  // typedef void* __builtin_va_list;
  QualType T = Context->getPointerType(Context->VoidTy);
  return Context->buildImplicitTypedef(T, "__builtin_va_list");
}
 
static TypedefDecl *
CreateAArch64ABIBuiltinVaListDecl(const ASTContext *Context) {
  // struct __va_list
  RecordDecl *VaListTagDecl = Context->buildImplicitRecord("__va_list");
  if (Context->getLangOpts().CPlusPlus) {
    // namespace std { struct __va_list {
    auto *NS = NamespaceDecl::Create(
        const_cast<ASTContext &>(*Context), Context->getTranslationUnitDecl(),
        /*Inline=*/false, SourceLocation(), SourceLocation(),
        &Context->Idents.get("std"),
        /*PrevDecl=*/nullptr, /*Nested=*/false);
    NS->setImplicit();
    VaListTagDecl->setDeclContext(NS);
  }
 
  VaListTagDecl->startDefinition();
 
  const size_t NumFields = 5;
  QualType FieldTypes[NumFields];
  const char *FieldNames[NumFields];
 
  // void *__stack;
  FieldTypes[0] = Context->getPointerType(Context->VoidTy);
  FieldNames[0] = "__stack";
 
  // void *__gr_top;
  FieldTypes[1] = Context->getPointerType(Context->VoidTy);
  FieldNames[1] = "__gr_top";
 
  // void *__vr_top;
  FieldTypes[2] = Context->getPointerType(Context->VoidTy);
  FieldNames[2] = "__vr_top";
 
  // int __gr_offs;
  FieldTypes[3] = Context->IntTy;
  FieldNames[3] = "__gr_offs";
 
  // int __vr_offs;
  FieldTypes[4] = Context->IntTy;
  FieldNames[4] = "__vr_offs";
 
  // Create fields
  for (unsigned i = 0; i < NumFields; ++i) {
    FieldDecl *Field = FieldDecl::Create(const_cast<ASTContext &>(*Context),
                                         VaListTagDecl,
                                         SourceLocation(),
                                         SourceLocation(),
                                         &Context->Idents.get(FieldNames[i]),
                                         FieldTypes[i], /*TInfo=*/nullptr,
                                         /*BitWidth=*/nullptr,
                                         /*Mutable=*/false,
                                         ICIS_NoInit);
    Field->setAccess(AS_public);
    VaListTagDecl->addDecl(Field);
  }
  VaListTagDecl->completeDefinition();
  Context->VaListTagDecl = VaListTagDecl;
  CanQualType VaListTagType = Context->getCanonicalTagType(VaListTagDecl);
 
  // } __builtin_va_list;
  return Context->buildImplicitTypedef(VaListTagType, "__builtin_va_list");
}
 
static TypedefDecl *CreatePowerABIBuiltinVaListDecl(const ASTContext *Context) {
  // typedef struct __va_list_tag {
  RecordDecl *VaListTagDecl;
 
  VaListTagDecl = Context->buildImplicitRecord("__va_list_tag");
  VaListTagDecl->startDefinition();
 
  const size_t NumFields = 5;
  QualType FieldTypes[NumFields];
  const char *FieldNames[NumFields];
 
  //   unsigned char gpr;
  FieldTypes[0] = Context->UnsignedCharTy;
  FieldNames[0] = "gpr";
 
  //   unsigned char fpr;
  FieldTypes[1] = Context->UnsignedCharTy;
  FieldNames[1] = "fpr";
 
  //   unsigned short reserved;
  FieldTypes[2] = Context->UnsignedShortTy;
  FieldNames[2] = "reserved";
 
  //   void* overflow_arg_area;
  FieldTypes[3] = Context->getPointerType(Context->VoidTy);
  FieldNames[3] = "overflow_arg_area";
 
  //   void* reg_save_area;
  FieldTypes[4] = Context->getPointerType(Context->VoidTy);
  FieldNames[4] = "reg_save_area";
 
  // Create fields
  for (unsigned i = 0; i < NumFields; ++i) {
    FieldDecl *Field = FieldDecl::Create(*Context, VaListTagDecl,
                                         SourceLocation(),
                                         SourceLocation(),
                                         &Context->Idents.get(FieldNames[i]),
                                         FieldTypes[i], /*TInfo=*/nullptr,
                                         /*BitWidth=*/nullptr,
                                         /*Mutable=*/false,
                                         ICIS_NoInit);
    Field->setAccess(AS_public);
    VaListTagDecl->addDecl(Field);
  }
  VaListTagDecl->completeDefinition();
  Context->VaListTagDecl = VaListTagDecl;
  CanQualType VaListTagType = Context->getCanonicalTagType(VaListTagDecl);
 
  // } __va_list_tag;
  TypedefDecl *VaListTagTypedefDecl =
      Context->buildImplicitTypedef(VaListTagType, "__va_list_tag");
 
  QualType VaListTagTypedefType =
      Context->getTypedefType(ElaboratedTypeKeyword::None,
                              /*Qualifier=*/std::nullopt, VaListTagTypedefDecl);
 
  // typedef __va_list_tag __builtin_va_list[1];
  llvm::APInt Size(Context->getTypeSize(Context->getSizeType()), 1);
  QualType VaListTagArrayType = Context->getConstantArrayType(
      VaListTagTypedefType, Size, nullptr, ArraySizeModifier::Normal, 0);
  return Context->buildImplicitTypedef(VaListTagArrayType, "__builtin_va_list");
}
 
static TypedefDecl *
CreateX86_64ABIBuiltinVaListDecl(const ASTContext *Context) {
  // struct __va_list_tag {
  RecordDecl *VaListTagDecl;
  VaListTagDecl = Context->buildImplicitRecord("__va_list_tag");
  VaListTagDecl->startDefinition();
 
  const size_t NumFields = 4;
  QualType FieldTypes[NumFields];
  const char *FieldNames[NumFields];
 
  //   unsigned gp_offset;
  FieldTypes[0] = Context->UnsignedIntTy;
  FieldNames[0] = "gp_offset";
 
  //   unsigned fp_offset;
  FieldTypes[1] = Context->UnsignedIntTy;
  FieldNames[1] = "fp_offset";
 
  //   void* overflow_arg_area;
  FieldTypes[2] = Context->getPointerType(Context->VoidTy);
  FieldNames[2] = "overflow_arg_area";
 
  //   void* reg_save_area;
  FieldTypes[3] = Context->getPointerType(Context->VoidTy);
  FieldNames[3] = "reg_save_area";
 
  // Create fields
  for (unsigned i = 0; i < NumFields; ++i) {
    FieldDecl *Field = FieldDecl::Create(const_cast<ASTContext &>(*Context),
                                         VaListTagDecl,
                                         SourceLocation(),
                                         SourceLocation(),
                                         &Context->Idents.get(FieldNames[i]),
                                         FieldTypes[i], /*TInfo=*/nullptr,
                                         /*BitWidth=*/nullptr,
                                         /*Mutable=*/false,
                                         ICIS_NoInit);
    Field->setAccess(AS_public);
    VaListTagDecl->addDecl(Field);
  }
  VaListTagDecl->completeDefinition();
  Context->VaListTagDecl = VaListTagDecl;
  CanQualType VaListTagType = Context->getCanonicalTagType(VaListTagDecl);
 
  // };
 
  // typedef struct __va_list_tag __builtin_va_list[1];
  llvm::APInt Size(Context->getTypeSize(Context->getSizeType()), 1);
  QualType VaListTagArrayType = Context->getConstantArrayType(
      VaListTagType, Size, nullptr, ArraySizeModifier::Normal, 0);
  return Context->buildImplicitTypedef(VaListTagArrayType, "__builtin_va_list");
}
 
static TypedefDecl *