xref: /external/clang/lib/AST/ASTContext.cpp

//===--- ASTContext.cpp - Context to hold long-lived AST nodes ------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements the ASTContext interface.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/ASTContext.h"
#include "CXXABI.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/Attr.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/Comment.h"
#include "clang/AST/CommentCommandTraits.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclContextInternals.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.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/RecordLayout.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/VTableBuilder.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Support/Capacity.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <map>

using namespace clang;

unsigned ASTContext::NumImplicitDefaultConstructors;
unsigned ASTContext::NumImplicitDefaultConstructorsDeclared;
unsigned ASTContext::NumImplicitCopyConstructors;
unsigned ASTContext::NumImplicitCopyConstructorsDeclared;
unsigned ASTContext::NumImplicitMoveConstructors;
unsigned ASTContext::NumImplicitMoveConstructorsDeclared;
unsigned ASTContext::NumImplicitCopyAssignmentOperators;
unsigned ASTContext::NumImplicitCopyAssignmentOperatorsDeclared;
unsigned ASTContext::NumImplicitMoveAssignmentOperators;
unsigned ASTContext::NumImplicitMoveAssignmentOperatorsDeclared;
unsigned ASTContext::NumImplicitDestructors;
unsigned ASTContext::NumImplicitDestructorsDeclared;

enum FloatingRank {
  HalfRank, FloatRank, DoubleRank, LongDoubleRank, Float128Rank
};

RawComment *ASTContext::getRawCommentForDeclNoCache(const Decl *D) const {
  if (!CommentsLoaded && ExternalSource) {
    ExternalSource->ReadComments();

#ifndef NDEBUG
    ArrayRef<RawComment *> RawComments = Comments.getComments();
    assert(std::is_sorted(RawComments.begin(), RawComments.end(),
                          BeforeThanCompare<RawComment>(SourceMgr)));
#endif

    CommentsLoaded = true;
  }

  assert(D);

  // User can not attach documentation to implicit declarations.
  if (D->isImplicit())
    return nullptr;

  // User can not attach documentation to implicit instantiations.
  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return nullptr;
  }

  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
    if (VD->isStaticDataMember() &&
        VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return nullptr;
  }

  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(D)) {
    if (CRD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return nullptr;
  }

  if (const ClassTemplateSpecializationDecl *CTSD =
          dyn_cast<ClassTemplateSpecializationDecl>(D)) {
    TemplateSpecializationKind TSK = CTSD->getSpecializationKind();
    if (TSK == TSK_ImplicitInstantiation ||
        TSK == TSK_Undeclared)
      return nullptr;
  }

  if (const EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
    if (ED->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
      return nullptr;
  }
  if (const TagDecl *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 nullptr;
  }
  // TODO: handle comments for function parameters properly.
  if (isa<ParmVarDecl>(D))
    return nullptr;

  // TODO: we could look up template parameter documentation in the template
  // documentation.
  if (isa<TemplateTypeParmDecl>(D) ||
      isa<NonTypeTemplateParmDecl>(D) ||
      isa<TemplateTemplateParmDecl>(D))
    return nullptr;

  ArrayRef<RawComment *> RawComments = Comments.getComments();

  // If there are no comments anywhere, we won't find anything.
  if (RawComments.empty())
    return nullptr;

  // 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 DeclLoc;
  if (isa<ObjCMethodDecl>(D) || isa<ObjCContainerDecl>(D) ||
      isa<ObjCPropertyDecl>(D) ||
      isa<RedeclarableTemplateDecl>(D) ||
      isa<ClassTemplateSpecializationDecl>(D))
    DeclLoc = D->getLocStart();
  else {
    DeclLoc = D->getLocation();
    if (DeclLoc.isMacroID()) {
      if (isa<TypedefDecl>(D)) {
        // If location of the typedef name is in a macro, it is because being
        // declared via a macro. Try using declaration's starting location as
        // the "declaration location".
        DeclLoc = D->getLocStart();
      } else if (const TagDecl *TD = dyn_cast<TagDecl>(D)) {
        // If location of the tag decl is inside a macro, but the spelling of
        // the tag name comes from a macro argument, it looks like a special
        // macro like NS_ENUM is being used to define the tag decl.  In that
        // case, adjust the source location to the expansion loc so that we can
        // attach the comment to the tag decl.
        if (SourceMgr.isMacroArgExpansion(DeclLoc) &&
            TD->isCompleteDefinition())
          DeclLoc = SourceMgr.getExpansionLoc(DeclLoc);
      }
    }
  }

  // If the declaration doesn't map directly to a location in a file, we
  // can't find the comment.
  if (DeclLoc.isInvalid() || !DeclLoc.isFileID())
    return nullptr;

  // Find the comment that occurs just after this declaration.
  ArrayRef<RawComment *>::iterator Comment;
  {
    // When searching for comments during parsing, the comment we are looking
    // for is usually among the last two comments we parsed -- check them
    // first.
    RawComment CommentAtDeclLoc(
        SourceMgr, SourceRange(DeclLoc), false,
        LangOpts.CommentOpts.ParseAllComments);
    BeforeThanCompare<RawComment> Compare(SourceMgr);
    ArrayRef<RawComment *>::iterator MaybeBeforeDecl = RawComments.end() - 1;
    bool Found = Compare(*MaybeBeforeDecl, &CommentAtDeclLoc);
    if (!Found && RawComments.size() >= 2) {
      MaybeBeforeDecl--;
      Found = Compare(*MaybeBeforeDecl, &CommentAtDeclLoc);
    }

    if (Found) {
      Comment = MaybeBeforeDecl + 1;
      assert(Comment == std::lower_bound(RawComments.begin(), RawComments.end(),
                                         &CommentAtDeclLoc, Compare));
    } else {
      // Slow path.
      Comment = std::lower_bound(RawComments.begin(), RawComments.end(),
                                 &CommentAtDeclLoc, Compare);
    }
  }

  // Decompose the location for the declaration and find the beginning of the
  // file buffer.
  std::pair<FileID, unsigned> DeclLocDecomp = SourceMgr.getDecomposedLoc(DeclLoc);

  // First check whether we have a trailing comment.
  if (Comment != RawComments.end() &&
      (*Comment)->isDocumentation() && (*Comment)->isTrailingComment() &&
      (isa<FieldDecl>(D) || isa<EnumConstantDecl>(D) || isa<VarDecl>(D) ||
       isa<ObjCMethodDecl>(D) || isa<ObjCPropertyDecl>(D))) {
    std::pair<FileID, unsigned> CommentBeginDecomp
      = SourceMgr.getDecomposedLoc((*Comment)->getSourceRange().getBegin());
    // Check that Doxygen trailing comment comes after the declaration, starts
    // on the same line and in the same file as the declaration.
    if (DeclLocDecomp.first == CommentBeginDecomp.first &&
        SourceMgr.getLineNumber(DeclLocDecomp.first, DeclLocDecomp.second)
          == SourceMgr.getLineNumber(CommentBeginDecomp.first,
                                     CommentBeginDecomp.second)) {
      return *Comment;
    }
  }

  // The comment just after the declaration was not a trailing comment.
  // Let's look at the previous comment.
  if (Comment == RawComments.begin())
    return nullptr;
  --Comment;

  // Check that we actually have a non-member Doxygen comment.
  if (!(*Comment)->isDocumentation() || (*Comment)->isTrailingComment())
    return nullptr;

  // Decompose the end of the comment.
  std::pair<FileID, unsigned> CommentEndDecomp
    = SourceMgr.getDecomposedLoc((*Comment)->getSourceRange().getEnd());

  // If the comment and the declaration aren't in the same file, then they
  // aren't related.
  if (DeclLocDecomp.first != CommentEndDecomp.first)
    return nullptr;

  // 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 + CommentEndDecomp.second,
                 DeclLocDecomp.second - CommentEndDecomp.second);

  // There should be no other declarations or preprocessor directives between
  // comment and declaration.
  if (Text.find_first_of(";{}#@") != StringRef::npos)
    return nullptr;

  return *Comment;
}

namespace {
/// If we have a 'templated' declaration for a template, adjust 'D' to
/// refer to the actual template.
/// If we have an implicit instantiation, adjust 'D' to refer to template.
const Decl *adjustDeclToTemplate(const Decl *D) {
  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    // Is this function declaration part of a function template?
    if (const FunctionTemplateDecl *FTD = FD->getDescribedFunctionTemplate())
      return FTD;

    // Nothing to do if function is not an implicit instantiation.
    if (FD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
      return D;

    // Function is an implicit instantiation of a function template?
    if (const FunctionTemplateDecl *FTD = FD->getPrimaryTemplate())
      return FTD;

    // Function is instantiated from a member definition of a class template?
    if (const FunctionDecl *MemberDecl =
            FD->getInstantiatedFromMemberFunction())
      return MemberDecl;

    return D;
  }
  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
    // Static data member is instantiated from a member definition of a class
    // template?
    if (VD->isStaticDataMember())
      if (const VarDecl *MemberDecl = VD->getInstantiatedFromStaticDataMember())
        return MemberDecl;

    return D;
  }
  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(D)) {
    // Is this class declaration part of a class template?
    if (const ClassTemplateDecl *CTD = CRD->getDescribedClassTemplate())
      return CTD;

    // Class is an implicit instantiation of a class template or partial
    // specialization?
    if (const ClassTemplateSpecializationDecl *CTSD =
            dyn_cast<ClassTemplateSpecializationDecl>(CRD)) {
      if (CTSD->getSpecializationKind() != TSK_ImplicitInstantiation)
        return D;
      llvm::PointerUnion<ClassTemplateDecl *,
                         ClassTemplatePartialSpecializationDecl *>
          PU = CTSD->getSpecializedTemplateOrPartial();
      return PU.is<ClassTemplateDecl*>() ?
          static_cast<const Decl*>(PU.get<ClassTemplateDecl *>()) :
          static_cast<const Decl*>(
              PU.get<ClassTemplatePartialSpecializationDecl *>());
    }

    // Class is instantiated from a member definition of a class template?
    if (const MemberSpecializationInfo *Info =
                   CRD->getMemberSpecializationInfo())
      return Info->getInstantiatedFrom();

    return D;
  }
  if (const EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
    // Enum is instantiated from a member definition of a class template?
    if (const EnumDecl *MemberDecl = ED->getInstantiatedFromMemberEnum())
      return MemberDecl;

    return D;
  }
  // FIXME: Adjust alias templates?
  return D;
}
} // anonymous namespace

const RawComment *ASTContext::getRawCommentForAnyRedecl(
                                                const Decl *D,
                                                const Decl **OriginalDecl) const {
  D = adjustDeclToTemplate(D);

  // Check whether we have cached a comment for this declaration already.
  {
    llvm::DenseMap<const Decl *, RawCommentAndCacheFlags>::iterator Pos =
        RedeclComments.find(D);
    if (Pos != RedeclComments.end()) {
      const RawCommentAndCacheFlags &Raw = Pos->second;
      if (Raw.getKind() != RawCommentAndCacheFlags::NoCommentInDecl) {
        if (OriginalDecl)
          *OriginalDecl = Raw.getOriginalDecl();
        return Raw.getRaw();
      }
    }
  }

  // Search for comments attached to declarations in the redeclaration chain.
  const RawComment *RC = nullptr;
  const Decl *OriginalDeclForRC = nullptr;
  for (auto I : D->redecls()) {
    llvm::DenseMap<const Decl *, RawCommentAndCacheFlags>::iterator Pos =
        RedeclComments.find(I);
    if (Pos != RedeclComments.end()) {
      const RawCommentAndCacheFlags &Raw = Pos->second;
      if (Raw.getKind() != RawCommentAndCacheFlags::NoCommentInDecl) {
        RC = Raw.getRaw();
        OriginalDeclForRC = Raw.getOriginalDecl();
        break;
      }
    } else {
      RC = getRawCommentForDeclNoCache(I);
      OriginalDeclForRC = I;
      RawCommentAndCacheFlags Raw;
      if (RC) {
        // Call order swapped to work around ICE in VS2015 RTM (Release Win32)
        // https://connect.microsoft.com/VisualStudio/feedback/details/1741530
        Raw.setKind(RawCommentAndCacheFlags::FromDecl);
        Raw.setRaw(RC);
      } else
        Raw.setKind(RawCommentAndCacheFlags::NoCommentInDecl);
      Raw.setOriginalDecl(I);
      RedeclComments[I] = Raw;
      if (RC)
        break;
    }
  }

  // If we found a comment, it should be a documentation comment.
  assert(!RC || RC->isDocumentation());

  if (OriginalDecl)
    *OriginalDecl = OriginalDeclForRC;

  // Update cache for every declaration in the redeclaration chain.
  RawCommentAndCacheFlags Raw;
  Raw.setRaw(RC);
  Raw.setKind(RawCommentAndCacheFlags::FromRedecl);
  Raw.setOriginalDecl(OriginalDeclForRC);

  for (auto I : D->redecls()) {
    RawCommentAndCacheFlags &R = RedeclComments[I];
    if (R.getKind() == RawCommentAndCacheFlags::NoCommentInDecl)
      R = Raw;
  }

  return RC;
}

static void addRedeclaredMethods(const ObjCMethodDecl *ObjCMethod,
                   SmallVectorImpl<const NamedDecl *> &Redeclared) {
  const DeclContext *DC = ObjCMethod->getDeclContext();
  if (const ObjCImplDecl *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);
    }
  }
}

comments::FullComment *ASTContext::cloneFullComment(comments::FullComment *FC,
                                                    const Decl *D) const {
  comments::DeclInfo *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->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;

  const RawComment *RC = getRawCommentForAnyRedecl(D, &OriginalDecl);
  if (!RC) {
    if (isa<ObjCMethodDecl>(D) || isa<FunctionDecl>(D)) {
      SmallVector<const NamedDecl*, 8> Overridden;
      const ObjCMethodDecl *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 TypedefNameDecl *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 TagType *TT = QT->getAs<TagType>())
        if (const Decl *TD = TT->getDecl())
          if (comments::FullComment *FC = getCommentForDecl(TD, PP))
            return cloneFullComment(FC, D);
    }
    else if (const ObjCInterfaceDecl *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 ObjCCategoryDecl *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 CXXRecordDecl *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)
    return getCommentForDecl(OriginalDecl, PP);

  comments::FullComment *FC = RC->parse(*this, PP, D);
  ParsedComments[Canonical] = FC;
  return FC;
}

void
ASTContext::CanonicalTemplateTemplateParm::Profile(llvm::FoldingSetNodeID &ID,
                                               TemplateTemplateParmDecl *Parm) {
  ID.AddInteger(Parm->getDepth());
  ID.AddInteger(Parm->getPosition());
  ID.AddBoolean(Parm->isParameterPack());

  TemplateParameterList *Params = Parm->getTemplateParameters();
  ID.AddInteger(Params->size());
  for (TemplateParameterList::const_iterator P = Params->begin(),
                                          PEnd = Params->end();
       P != PEnd; ++P) {
    if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*P)) {
      ID.AddInteger(0);
      ID.AddBoolean(TTP->isParameterPack());
      continue;
    }

    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
      ID.AddInteger(1);
      ID.AddBoolean(NTTP->isParameterPack());
      ID.AddPointer(NTTP->getType().getCanonicalType().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;
    }

    TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
    ID.AddInteger(2);
    Profile(ID, TTP);
  }
}

TemplateTemplateParmDecl *
ASTContext::getCanonicalTemplateTemplateParmDecl(
                                          TemplateTemplateParmDecl *TTP) const {
  // Check if we already have a canonical template template parameter.
  llvm::FoldingSetNodeID ID;
  CanonicalTemplateTemplateParm::Profile(ID, 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) {
    if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*P))
      CanonParams.push_back(
                  TemplateTypeParmDecl::Create(*this, getTranslationUnitDecl(),
                                               SourceLocation(),
                                               SourceLocation(),
                                               TTP->getDepth(),
                                               TTP->getIndex(), nullptr, false,
                                               TTP->isParameterPack()));
    else if (NonTypeTemplateParmDecl *NTTP
             = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
      QualType T = getCanonicalType(NTTP->getType());
      TypeSourceInfo *TInfo = getTrivialTypeSourceInfo(T);
      NonTypeTemplateParmDecl *Param;
      if (NTTP->isExpandedParameterPack()) {
        SmallVector<QualType, 2> ExpandedTypes;
        SmallVector<TypeSourceInfo *, 2> ExpandedTInfos;
        for (unsigned I = 0, N = NTTP->getNumExpansionTypes(); I != N; ++I) {
          ExpandedTypes.push_back(getCanonicalType(NTTP->getExpansionType(I)));
          ExpandedTInfos.push_back(
                                getTrivialTypeSourceInfo(ExpandedTypes.back()));
        }

        Param = NonTypeTemplateParmDecl::Create(*this, getTranslationUnitDecl(),
                                                SourceLocation(),
                                                SourceLocation(),
                                                NTTP->getDepth(),
                                                NTTP->getPosition(), nullptr,
                                                T,
                                                TInfo,
                                                ExpandedTypes,
                                                ExpandedTInfos);
      } else {
        Param = NonTypeTemplateParmDecl::Create(*this, getTranslationUnitDecl(),
                                                SourceLocation(),
                                                SourceLocation(),
                                                NTTP->getDepth(),
                                                NTTP->getPosition(), nullptr,
                                                T,
                                                NTTP->isParameterPack(),
                                                TInfo);
      }
      CanonParams.push_back(Param);

    } else
      CanonParams.push_back(getCanonicalTemplateTemplateParmDecl(
                                           cast<TemplateTemplateParmDecl>(*P)));
  }

  TemplateTemplateParmDecl *CanonTTP
    = TemplateTemplateParmDecl::Create(*this, getTranslationUnitDecl(),
                                       SourceLocation(), TTP->getDepth(),
                                       TTP->getPosition(),
                                       TTP->isParameterPack(),
                                       nullptr,
                         TemplateParameterList::Create(*this, SourceLocation(),
                                                       SourceLocation(),
                                                       CanonParams,
                                                       SourceLocation()));

  // 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;
}

CXXABI *ASTContext::createCXXABI(const TargetInfo &T) {
  if (!LangOpts.CPlusPlus) return nullptr;

  switch (T.getCXXABI().getKind()) {
  case TargetCXXABI::GenericARM: // Same as Itanium at this level
  case TargetCXXABI::iOS:
  case TargetCXXABI::iOS64:
  case TargetCXXABI::WatchOS:
  case TargetCXXABI::GenericAArch64:
  case TargetCXXABI::GenericMIPS:
  case TargetCXXABI::GenericItanium:
  case TargetCXXABI::WebAssembly:
    return CreateItaniumCXXABI(*this);
  case TargetCXXABI::Microsoft:
    return CreateMicrosoftCXXABI(*this);
  }
  llvm_unreachable("Invalid CXXABI type!");
}

static const LangAS::Map *getAddressSpaceMap(const TargetInfo &T,
                                             const LangOptions &LOpts) {
  if (LOpts.FakeAddressSpaceMap) {
    // The fake address space map must have a distinct entry for each
    // language-specific address space.
    static const unsigned FakeAddrSpaceMap[] = {
      1, // opencl_global
      2, // opencl_local
      3, // opencl_constant
      4, // opencl_generic
      5, // cuda_device
      6, // cuda_constant
      7  // cuda_shared
    };
    return &FakeAddrSpaceMap;
  } else {
    return &T.getAddressSpaceMap();
  }
}

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)
    : FunctionProtoTypes(this_()), TemplateSpecializationTypes(this_()),
      DependentTemplateSpecializationTypes(this_()),
      SubstTemplateTemplateParmPacks(this_()),
      GlobalNestedNameSpecifier(nullptr), Int128Decl(nullptr),
      UInt128Decl(nullptr), BuiltinVaListDecl(nullptr),
      BuiltinMSVaListDecl(nullptr), ObjCIdDecl(nullptr), ObjCSelDecl(nullptr),
      ObjCClassDecl(nullptr), ObjCProtocolClassDecl(nullptr), BOOLDecl(nullptr),
      CFConstantStringTagDecl(nullptr), CFConstantStringTypeDecl(nullptr),
      ObjCInstanceTypeDecl(nullptr), FILEDecl(nullptr), jmp_bufDecl(nullptr),
      sigjmp_bufDecl(nullptr), ucontext_tDecl(nullptr),
      BlockDescriptorType(nullptr), BlockDescriptorExtendedType(nullptr),
      cudaConfigureCallDecl(nullptr), FirstLocalImport(), LastLocalImport(),
      ExternCContext(nullptr), MakeIntegerSeqDecl(nullptr),
      TypePackElementDecl(nullptr), SourceMgr(SM), LangOpts(LOpts),
      SanitizerBL(new SanitizerBlacklist(LangOpts.SanitizerBlacklistFiles, SM)),
      AddrSpaceMap(nullptr), Target(nullptr), AuxTarget(nullptr),
      PrintingPolicy(LOpts), Idents(idents), Selectors(sels),
      BuiltinInfo(builtins), DeclarationNames(*this), ExternalSource(nullptr),
      Listener(nullptr), Comments(SM), CommentsLoaded(false),
      CommentCommandTraits(BumpAlloc, LOpts.CommentOpts), LastSDM(nullptr, 0) {
  TUDecl = TranslationUnitDecl::Create(*this);
}

ASTContext::~ASTContext() {
  ReleaseParentMapEntries();

  // 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);

  // ASTRecordLayout objects in ASTRecordLayouts must always be destroyed
  // because they can contain DenseMaps.
  for (llvm::DenseMap<const ObjCContainerDecl*,
       const ASTRecordLayout*>::iterator
       I = ObjCLayouts.begin(), E = ObjCLayouts.end(); I != E; )
    // Increment in loop to prevent using deallocated memory.
    if (ASTRecordLayout *R = const_cast<ASTRecordLayout*>((I++)->second))
      R->Destroy(*this);

  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 (ASTRecordLayout *R = const_cast<ASTRecordLayout*>((I++)->second))
      R->Destroy(*this);
  }

  for (llvm::DenseMap<const Decl*, AttrVec*>::iterator A = DeclAttrs.begin(),
                                                    AEnd = DeclAttrs.end();
       A != AEnd; ++A)
    A->second->~AttrVec();

  for (std::pair<const MaterializeTemporaryExpr *, APValue *> &MTVPair :
       MaterializedTemporaryValues)
    MTVPair.second->~APValue();

  llvm::DeleteContainerSeconds(MangleNumberingContexts);
}

void ASTContext::ReleaseParentMapEntries() {
  if (!PointerParents) return;
  for (const auto &Entry : *PointerParents) {
    if (Entry.second.is<ast_type_traits::DynTypedNode *>()) {
      delete Entry.second.get<ast_type_traits::DynTypedNode *>();
    } else if (Entry.second.is<ParentVector *>()) {
      delete Entry.second.get<ParentVector *>();
    }
  }
  for (const auto &Entry : *OtherParents) {
    if (Entry.second.is<ast_type_traits::DynTypedNode *>()) {
      delete Entry.second.get<ast_type_traits::DynTypedNode *>();
    } else if (Entry.second.is<ParentVector *>()) {
      delete Entry.second.get<ParentVector *>();
    }
  }
}

void ASTContext::AddDeallocation(void (*Callback)(void*), void *Data) {
  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.def"
    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\n";                                         \
  TotalBytes += counts[Idx] * sizeof(Name##Type);                       \
  ++Idx;
#define ABSTRACT_TYPE(Name, Parent)
#include "clang/AST/TypeNodes.def"

  llvm::errs() << "Total bytes = " << TotalBytes << "\n";

  // Implicit special member functions.
  llvm::errs() << NumImplicitDefaultConstructorsDeclared << "/"
               << NumImplicitDefaultConstructors
               << " implicit default constructors created\n";
  llvm::errs() << NumImplicitCopyConstructorsDeclared << "/"
               << NumImplicitCopyConstructors
               << " implicit copy constructors created\n";
  if (getLangOpts().CPlusPlus)
    llvm::errs() << NumImplicitMoveConstructorsDeclared << "/"
                 << NumImplicitMoveConstructors
                 << " implicit move constructors created\n";
  llvm::errs() << NumImplicitCopyAssignmentOperatorsDeclared << "/"
               << NumImplicitCopyAssignmentOperators
               << " implicit copy assignment operators created\n";
  if (getLangOpts().CPlusPlus)
    llvm::errs() << NumImplicitMoveAssignmentOperatorsDeclared << "/"
                 << NumImplicitMoveAssignmentOperators
                 << " implicit move assignment operators created\n";
  llvm::errs() << NumImplicitDestructorsDeclared << "/"
               << NumImplicitDestructors
               << " implicit destructors created\n";

  if (ExternalSource) {
    llvm::errs() << "\n";
    ExternalSource->PrintStats();
  }

  BumpAlloc.PrintStats();
}

void ASTContext::mergeDefinitionIntoModule(NamedDecl *ND, Module *M,
                                           bool NotifyListeners) {
  if (NotifyListeners)
    if (auto *Listener = getASTMutationListener())
      Listener->RedefinedHiddenDefinition(ND, M);

  if (getLangOpts().ModulesLocalVisibility)
    MergedDefModules[ND].push_back(M);
  else
    ND->setHidden(false);
}

void ASTContext::deduplicateMergedDefinitonsFor(NamedDecl *ND) {
  auto It = MergedDefModules.find(ND);
  if (It == MergedDefModules.end())
    return;

  auto &Merged = It->second;
  llvm::DenseSet<Module*> Found;
  for (Module *&M : Merged)
    if (!Found.insert(M).second)
      M = nullptr;
  Merged.erase(std::remove(Merged.begin(), Merged.end(), nullptr), Merged.end());
}

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, TUDecl, II, BTK);
  BuiltinTemplate->setImplicit();
  TUDecl->addDecl(BuiltinTemplate);

  return BuiltinTemplate;
}

BuiltinTemplateDecl *
ASTContext::getMakeIntegerSeqDecl() const {
  if (!MakeIntegerSeqDecl)
    MakeIntegerSeqDecl = buildBuiltinTemplateDecl(BTK__make_integer_seq,
                                                  getMakeIntegerSeqName());
  return MakeIntegerSeqDecl;
}

BuiltinTemplateDecl *
ASTContext::getTypePackElementDecl() const {
  if (!TypePackElementDecl)
    TypePackElementDecl = buildBuiltinTemplateDecl(BTK__type_pack_element,
                                                   getTypePackElementName());
  return TypePackElementDecl;
}

RecordDecl *ASTContext::buildImplicitRecord(StringRef Name,
                                            RecordDecl::TagKind TK) const {
  SourceLocation Loc;
  RecordDecl *NewDecl;
  if (getLangOpts().CPlusPlus)
    NewDecl = CXXRecordDecl::Create(*this, TK, getTranslationUnitDecl(), Loc,
                                    Loc, &Idents.get(Name));
  else
    NewDecl = RecordDecl::Create(*this, TK, getTranslationUnitDecl(), Loc, Loc,
                                 &Idents.get(Name));
  NewDecl->setImplicit();
  NewDecl->addAttr(TypeVisibilityAttr::CreateImplicit(
      const_cast<ASTContext &>(*this), TypeVisibilityAttr::Default));
  return NewDecl;
}

TypedefDecl *ASTContext::buildImplicitTypedef(QualType T,
                                              StringRef Name) const {
  TypeSourceInfo *TInfo = getTrivialTypeSourceInfo(T);
  TypedefDecl *NewDecl = TypedefDecl::Create(
      const_cast<ASTContext &>(*this), getTranslationUnitDecl(),
      SourceLocation(), SourceLocation(), &Idents.get(Name), TInfo);
  NewDecl->setImplicit();
  return NewDecl;
}

TypedefDecl *ASTContext::getInt128Decl() const {
  if (!Int128Decl)
    Int128Decl = buildImplicitTypedef(Int128Ty, "__int128_t");
  return Int128Decl;
}

TypedefDecl *ASTContext::getUInt128Decl() const {
  if (!UInt128Decl)
    UInt128Decl = buildImplicitTypedef(UnsignedInt128Ty, "__uint128_t");
  return UInt128Decl;
}

void ASTContext::InitBuiltinType(CanQualType &R, BuiltinType::Kind K) {
  BuiltinType *Ty = new (*this, TypeAlignment) BuiltinType(K);
  R = CanQualType::CreateUnsafe(QualType(Ty, 0));
  Types.push_back(Ty);
}

void ASTContext::InitBuiltinTypes(const TargetInfo &Target,
                                  const TargetInfo *AuxTarget) {
  assert((!this->Target || this->Target == &Target) &&
         "Incorrect target reinitialization");
  assert(VoidTy.isNull() && "Context reinitialized?");

  this->Target = &Target;
  this->AuxTarget = AuxTarget;

  ABI.reset(createCXXABI(Target));
  AddrSpaceMap = getAddressSpaceMap(Target, LangOpts);
  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);

  // 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());

  if (LangOpts.CPlusPlus) // C++0x 3.9.1p5, extension for C++
    InitBuiltinType(Char16Ty,           BuiltinType::Char16);
  else // C99
    Char16Ty = getFromTargetType(Target.getChar16Type());

  if (LangOpts.CPlusPlus) // C++0x 3.9.1p5, extension for C++
    InitBuiltinType(Char32Ty,           BuiltinType::Char32);
  else // C99
    Char32Ty = getFromTargetType(Target.getChar32Type());

  // Placeholder type for type-dependent expressions whose type is
  // completely unknown. No code should ever check a type against
  // DependentTy and users should never see it; however, it is here to
  // help diagnose failures to properly check for type-dependent
  // expressions.
  InitBuiltinType(DependentTy,         BuiltinType::Dependent);

  // Placeholder type for functions.
  InitBuiltinType(OverloadTy,          BuiltinType::Overload);

  // Placeholder type for bound members.
  InitBuiltinType(BoundMemberTy,       BuiltinType::BoundMember);

  // Placeholder type for pseudo-objects.
  InitBuiltinType(PseudoObjectTy,      BuiltinType::PseudoObject);

  // "any" type; useful for debugger-like clients.
  InitBuiltinType(UnknownAnyTy,        BuiltinType::UnknownAny);

  // Placeholder type for unbridged ARC casts.
  InitBuiltinType(ARCUnbridgedCastTy,  BuiltinType::ARCUnbridgedCast);

  // Placeholder type for builtin functions.
  InitBuiltinType(BuiltinFnTy,  BuiltinType::BuiltinFn);

  // Placeholder type for OMP array sections.
  if (LangOpts.OpenMP)
    InitBuiltinType(OMPArraySectionTy, BuiltinType::OMPArraySection);

  // C99 6.2.5p11.
  FloatComplexTy      = getComplexType(FloatTy);
  DoubleComplexTy     = getComplexType(DoubleTy);
  LongDoubleComplexTy = getComplexType(LongDoubleTy);
  Float128ComplexTy   = getComplexType(Float128Ty);

  // 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(OCLNDRangeTy, BuiltinType::OCLNDRange);
    InitBuiltinType(OCLReserveIDTy, BuiltinType::OCLReserveID);
  }

  // Builtin type for __objc_yes and __objc_no
  ObjCBuiltinBoolTy = (Target.useSignedCharForObjCBool() ?
                       SignedCharTy : BoolTy);

  ObjCConstantStringType = QualType();

  ObjCSuperType = QualType();

  // void * type
  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);

  // Builtin type used to help define __builtin_va_list.
  VaListTagDecl = nullptr;
}

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;
}

/// \brief 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 TemplateOrSpecializationInfo();

  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;
}

FunctionDecl *ASTContext::getClassScopeSpecializationPattern(
                                                     const FunctionDecl *FD){
  assert(FD && "Specialization is 0");
  llvm::DenseMap<const FunctionDecl*, FunctionDecl *>::const_iterator Pos
    = ClassScopeSpecializationPattern.find(FD);
  if (Pos == ClassScopeSpecializationPattern.end())
    return nullptr;

  return Pos->second;
}

void ASTContext::setClassScopeSpecializationPattern(FunctionDecl *FD,
                                        FunctionDecl *Pattern) {
  assert(FD && "Specialization is 0");
  assert(Pattern && "Class scope specialization pattern is 0");
  ClassScopeSpecializationPattern[FD] = Pattern;
}

NamedDecl *
ASTContext::getInstantiatedFromUsingDecl(UsingDecl *UUD) {
  llvm::DenseMap<UsingDecl *, NamedDecl *>::const_iterator Pos
    = InstantiatedFromUsingDecl.find(UUD);
  if (Pos == InstantiatedFromUsingDecl.end())
    return nullptr;

  return Pos->second;
}

void
ASTContext::setInstantiatedFromUsingDecl(UsingDecl *Inst, NamedDecl *Pattern) {
  assert((isa<UsingDecl>(Pattern) ||
          isa<UnresolvedUsingValueDecl>(Pattern) ||
          isa<UnresolvedUsingTypenameDecl>(Pattern)) &&
         "pattern decl is not a using decl");
  assert(!InstantiatedFromUsingDecl[Inst] && "pattern already exists");
  InstantiatedFromUsingDecl[Inst] = Pattern;
}

UsingShadowDecl *
ASTContext::getInstantiatedFromUsingShadowDecl(UsingShadowDecl *Inst) {
  llvm::DenseMap<UsingShadowDecl*, UsingShadowDecl*>::const_iterator Pos
    = InstantiatedFromUsingShadowDecl.find(Inst);
  if (Pos == InstantiatedFromUsingShadowDecl.end())
    return nullptr;

  return Pos->second;
}

void
ASTContext::setInstantiatedFromUsingShadowDecl(UsingShadowDecl *Inst,
                                               UsingShadowDecl *Pattern) {
  assert(!InstantiatedFromUsingShadowDecl[Inst] && "pattern already exists");
  InstantiatedFromUsingShadowDecl[Inst] = Pattern;
}

FieldDecl *ASTContext::getInstantiatedFromUnnamedFieldDecl(FieldDecl *Field) {
  llvm::DenseMap<FieldDecl *, FieldDecl *>::iterator Pos
    = InstantiatedFromUnnamedFieldDecl.find(Field);
  if (Pos == InstantiatedFromUnnamedFieldDecl.end())
    return nullptr;

  return Pos->second;
}

void ASTContext::setInstantiatedFromUnnamedFieldDecl(FieldDecl *Inst,
                                                     FieldDecl *Tmpl) {
  assert(!Inst->getDeclName() && "Instantiated field decl is not unnamed");
  assert(!Tmpl->getDeclName() && "Template field decl is not unnamed");
  assert(!InstantiatedFromUnnamedFieldDecl[Inst] &&
         "Already noted what unnamed field was instantiated from");

  InstantiatedFromUnnamedFieldDecl[Inst] = Tmpl;
}

ASTContext::overridden_cxx_method_iterator
ASTContext::overridden_methods_begin(const CXXMethodDecl *Method) const {
  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
      OverriddenMethods.find(Method->getCanonicalDecl());
  if (Pos == OverriddenMethods.end())
    return nullptr;
  return Pos->second.begin();
}

ASTContext::overridden_cxx_method_iterator
ASTContext::overridden_methods_end(const CXXMethodDecl *Method) const {
  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
      OverriddenMethods.find(Method->getCanonicalDecl());
  if (Pos == OverriddenMethods.end())
    return nullptr;
  return Pos->second.end();
}

unsigned
ASTContext::overridden_methods_size(const CXXMethodDecl *Method) const {
  llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector>::const_iterator Pos =
      OverriddenMethods.find(Method->getCanonicalDecl());
  if (Pos == OverriddenMethods.end())
    return 0;
  return Pos->second.size();
}

ASTContext::overridden_method_range
ASTContext::overridden_methods(const CXXMethodDecl *Method) const {
  return overridden_method_range(overridden_methods_begin(Method),
                                 overridden_methods_end(Method));
}

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 CXXMethodDecl *CXXMethod = dyn_cast<CXXMethodDecl>(D)) {
    Overridden.append(overridden_methods_begin(CXXMethod),
                      overridden_methods_end(CXXMethod));
    return;
  }

  const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(D);
  if (!Method)
    return;

  SmallVector<const ObjCMethodDecl *, 8> OverDecls;
  Method->getOverriddenMethods(OverDecls);
  Overridden.append(OverDecls.begin(), OverDecls.end());
}

void ASTContext::addedLocalImportDecl(ImportDecl *Import) {
  assert(!Import->NextLocalImport && "Import declaration already in the chain");
  assert(!Import->isFromASTFile() && "Non-local import declaration");
  if (!FirstLocalImport) {
    FirstLocalImport = Import;
    LastLocalImport = Import;
    return;
  }

  LastLocalImport->NextLocalImport = 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 {
  const BuiltinType *BT = T->getAs<BuiltinType>();
  assert(BT && "Not a floating point type!");
  switch (BT->getKind()) {
  default: llvm_unreachable("Not a floating point type!");
  case BuiltinType::Half:       return Target->getHalfFormat();
  case BuiltinType::Float:      return Target->getFloatFormat();
  case BuiltinType::Double:     return Target->getDoubleFormat();
  case BuiltinType::LongDouble: return Target->getLongDoubleFormat();
  case BuiltinType::Float128:   return Target->getFloat128Format();
  }
}

CharUnits ASTContext::getDeclAlign(const Decl *D, bool ForAlignof) const {
  unsigned Align = Target->getCharWidth();

  bool UseAlignAttrOnly = false;
  if (unsigned AlignFromAttr = D->getMaxAlignment()) {
    Align = AlignFromAttr;

    // __attribute__((aligned)) can increase or decrease alignment
    // *except* on a struct or struct member, where it only increases
    // alignment unless 'packed' is also specified.
    //
    // It is an error for alignas to decrease alignment, so we can
    // ignore that possibility;  Sema should diagnose it.
    if (isa<FieldDecl>(D)) {
      UseAlignAttrOnly = D->hasAttr<PackedAttr>() ||
        cast<FieldDecl>(D)->getParent()->hasAttr<PackedAttr>();
    } else {
      UseAlignAttrOnly = true;
    }
  }
  else if (isa<FieldDecl>(D))
      UseAlignAttrOnly =
        D->hasAttr<PackedAttr>() ||
        cast<FieldDecl>(D)->getParent()->hasAttr<PackedAttr>();

  // If we're using the align attribute only, just ignore everything
  // else about the declaration and its type.
  if (UseAlignAttrOnly) {
    // do nothing

  } else if (const ValueDecl *VD = dyn_cast<ValueDecl>(D)) {
    QualType T = VD->getType();
    if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
      if (ForAlignof)
        T = RT->getPointeeType();
      else
        T = getPointerType(RT->getPointeeType());
    }
    QualType BaseT = getBaseElementType(T);
    if (!BaseT->isIncompleteType() && !T->isFunctionType()) {
      // 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 (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
        if (VD->hasGlobalStorage() && !ForAlignof)
          Align = std::max(Align, getTargetInfo().getMinGlobalAlign());
      }
    }

    // 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 FieldDecl *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);
      }
    }
  }

  return toCharUnitsFromBits(Align);
}

// 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.
std::pair<CharUnits, CharUnits>
ASTContext::getTypeInfoDataSizeInChars(QualType T) const {
  std::pair<CharUnits, CharUnits> sizeAndAlign = 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 RecordType *RT = T->getAs<RecordType>()) {
      const ASTRecordLayout &layout = getASTRecordLayout(RT->getDecl());
      sizeAndAlign.first = layout.getDataSize();
    }
  }

  return sizeAndAlign;
}

/// getConstantArrayInfoInChars - Performing the computation in CharUnits
/// instead of in bits prevents overflowing the uint64_t for some large arrays.
std::pair<CharUnits, CharUnits>
static getConstantArrayInfoInChars(const ASTContext &Context,
                                   const ConstantArrayType *CAT) {
  std::pair<CharUnits, CharUnits> EltInfo =
      Context.getTypeInfoInChars(CAT->getElementType());
  uint64_t Size = CAT->getSize().getZExtValue();
  assert((Size == 0 || static_cast<uint64_t>(EltInfo.first.getQuantity()) <=
              (uint64_t)(-1)/Size) &&
         "Overflow in array type char size evaluation");
  uint64_t Width = EltInfo.first.getQuantity() * Size;
  unsigned Align = EltInfo.second.getQuantity();
  if (!Context.getTargetInfo().getCXXABI().isMicrosoft() ||
      Context.getTargetInfo().getPointerWidth(0) == 64)
    Width = llvm::alignTo(Width, Align);
  return std::make_pair(CharUnits::fromQuantity(Width),
                        CharUnits::fromQuantity(Align));
}

std::pair<CharUnits, CharUnits>
ASTContext::getTypeInfoInChars(const Type *T) const {
  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(T))
    return getConstantArrayInfoInChars(*this, CAT);
  TypeInfo Info = getTypeInfo(T);
  return std::make_pair(toCharUnitsFromBits(Info.Width),
                        toCharUnitsFromBits(Info.Align));
}

std::pair<CharUnits, CharUnits>
ASTContext::getTypeInfoInChars(QualType T) const {
  return getTypeInfoInChars(T.getTypePtr());
}

bool ASTContext::isAlignmentRequired(const Type *T) const {
  return getTypeInfo(T).AlignIsRequired;
}

bool ASTContext::isAlignmentRequired(QualType T) const {
  return isAlignmentRequired(T.getTypePtr());
}

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;
  bool AlignIsRequired = false;
  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.def"
    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:
    Width = 0;
    Align = getTypeAlign(cast<ArrayType>(T)->getElementType());
    break;

  case Type::ConstantArray: {
    const ConstantArrayType *CAT = cast<ConstantArrayType>(T);

    TypeInfo EltInfo = getTypeInfo(CAT->getElementType());
    uint64_t Size = CAT->getSize().getZExtValue();
    assert((Size == 0 || EltInfo.Width <= (uint64_t)(-1) / Size) &&
           "Overflow in array type bit size evaluation");
    Width = EltInfo.Width * Size;
    Align = EltInfo.Align;
    if (!getTargetInfo().getCXXABI().isMicrosoft() ||
        getTargetInfo().getPointerWidth(0) == 64)
      Width = llvm::alignTo(Width, Align);
    break;
  }
  case Type::ExtVector:
  case Type::Vector: {
    const VectorType *VT = cast<VectorType>(T);
    TypeInfo EltInfo = getTypeInfo(VT->getElementType());
    Width = EltInfo.Width * VT->getNumElements();
    Align = 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::NextPowerOf2(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;
    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:
      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 = 128; // int128_t is 128-bit aligned on all targets.
      break;
    case BuiltinType::Half:
      Width = Target->getHalfWidth();
      Align = Target->getHalfAlign();
      break;
    case BuiltinType::Float:
      Width = Target->getFloatWidth();
      Align = Target->getFloatAlign();
      break;
    case BuiltinType::Double:
      Width = Target->getDoubleWidth();
      Align = Target->getDoubleAlign();
      break;
    case BuiltinType::LongDouble:
      Width = Target->getLongDoubleWidth();
      Align = Target->getLongDoubleAlign();
      break;
    case BuiltinType::Float128:
      Width = Target->getFloat128Width();
      Align = Target->getFloat128Align();
      break;
    case BuiltinType::NullPtr:
      Width = Target->getPointerWidth(0); // C++ 3.9.1p11: sizeof(nullptr_t)
      Align = Target->getPointerAlign(0); //   == sizeof(void*)
      break;
    case BuiltinType::ObjCId:
    case BuiltinType::ObjCClass:
    case BuiltinType::ObjCSel:
      Width = Target->getPointerWidth(0);
      Align = Target->getPointerAlign(0);
      break;
    case BuiltinType::OCLSampler:
      // Samplers are modeled as integers.
      Width = Target->getIntWidth();
      Align = Target->getIntAlign();
      break;
    case BuiltinType::OCLEvent:
    case BuiltinType::OCLClkEvent:
    case BuiltinType::OCLQueue:
    case BuiltinType::OCLNDRange:
    case BuiltinType::OCLReserveID:
#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
    case BuiltinType::Id:
#include "clang/Basic/OpenCLImageTypes.def"

      // Currently these types are pointers to opaque types.
      Width = Target->getPointerWidth(0);
      Align = Target->getPointerAlign(0);
      break;
    }
    break;
  case Type::ObjCObjectPointer:
    Width = Target->getPointerWidth(0);
    Align = Target->getPointerAlign(0);
    break;
  case Type::BlockPointer: {
    unsigned AS = getTargetAddressSpace(
        cast<BlockPointerType>(T)->getPointeeType());
    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.
    unsigned AS = getTargetAddressSpace(
        cast<ReferenceType>(T)->getPointeeType());
    Width = Target->getPointerWidth(AS);
    Align = Target->getPointerAlign(AS);
    break;
  }
  case Type::Pointer: {
    unsigned AS = getTargetAddressSpace(cast<PointerType>(T)->getPointeeType());
    Width = Target->getPointerWidth(AS);
    Align = Target->getPointerAlign(AS);
    break;
  }
  case Type::MemberPointer: {
    const MemberPointerType *MPT = cast<MemberPointerType>(T);
    std::tie(Width, Align) = ABI->getMemberPointerWidthAndAlign(MPT);
    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 ObjCInterfaceType *ObjCI = cast<ObjCInterfaceType>(T);
    const ASTRecordLayout &Layout = getASTObjCInterfaceLayout(ObjCI->getDecl());
    Width = toBits(Layout.getSize());
    Align = toBits(Layout.getAlignment());
    break;
  }
  case Type::Record:
  case Type::Enum: {
    const TagType *TT = cast<TagType>(T);

    if (TT->getDecl()->isInvalidDecl()) {
      Width = 8;
      Align = 8;
      break;
    }

    if (const EnumType *ET = dyn_cast<EnumType>(TT)) {
      const EnumDecl *ED = ET->getDecl();
      TypeInfo Info =
          getTypeInfo(ED->getIntegerType()->getUnqualifiedDesugaredType());
      if (unsigned AttrAlign = ED->getMaxAlignment()) {
        Info.Align = AttrAlign;
        Info.AlignIsRequired = true;
      }
      return Info;
    }

    const RecordType *RT = cast<RecordType>(TT);
    const RecordDecl *RD = RT->getDecl();
    const ASTRecordLayout &Layout = getASTRecordLayout(RD);
    Width = toBits(Layout.getSize());
    Align = toBits(Layout.getAlignment());
    AlignIsRequired = RD->hasAttr<AlignedAttr>();
    break;
  }

  case Type::SubstTemplateTypeParm:
    return getTypeInfo(cast<SubstTemplateTypeParmType>(T)->
                       getReplacementType().getTypePtr());

  case Type::Auto: {
    const AutoType *A = cast<AutoType>(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::Typedef: {
    const TypedefNameDecl *Typedef = cast<TypedefType>(T)->getDecl();
    TypeInfo Info = getTypeInfo(Typedef->getUnderlyingType().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 = Typedef->getMaxAlignment()) {
      Align = AttrAlign;
      AlignIsRequired = true;
    } else {
      Align = Info.Align;
      AlignIsRequired = Info.AlignIsRequired;
    }
    Width = Info.Width;
    break;
  }

  case Type::Elaborated:
    return getTypeInfo(cast<ElaboratedType>(T)->getNamedType().getTypePtr());

  case Type::Attributed:
    return getTypeInfo(
                  cast<AttributedType>(T)->getEquivalentType().getTypePtr());

  case Type::Atomic: {
    // Start with the base type information.
    TypeInfo Info = getTypeInfo(cast<AtomicType>(T)->getValueType());
    Width = Info.Width;
    Align = Info.Align;

    // 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:
    if (Width != 0 && Width <= Target->getMaxAtomicPromoteWidth()) {
      // Round the size up to a power of 2.
      if (!llvm::isPowerOf2_64(Width))
        Width = llvm::NextPowerOf2(Width);

      // Set the alignment equal to the size.
      Align = static_cast<unsigned>(Width);
    }
  }
  break;

  case Type::Pipe: {
    TypeInfo Info = getTypeInfo(cast<PipeType>(T)->getElementType());
    Width = Info.Width;
    Align = Info.Align;
  }

  }

  assert(llvm::isPowerOf2_32(Align) && "Alignment must be power of 2");
  return TypeInfo(Width, Align, AlignIsRequired);
}

unsigned ASTContext::getOpenMPDefaultSimdAlign(QualType T) const {
  unsigned SimdAlign = getTargetInfo().getSimdDefaultAlign();
  // Target ppc64 with QPX: simd default alignment for pointer to double is 32.
  if ((getTargetInfo().getTriple().getArch() == llvm::Triple::ppc64 ||
       getTargetInfo().getTriple().getArch() == llvm::Triple::ppc64le) &&
      getTargetInfo().getABI() == "elfv1-qpx" &&
      T->isSpecificBuiltinType(BuiltinType::Double))
    SimdAlign = 256;
  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).first;
}
CharUnits ASTContext::getTypeSizeInChars(const Type *T) const {
  return getTypeInfoInChars(T).first;
}

/// 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));
}

/// 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 to overalign
/// a data type.
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;

  // Double and long long should be naturally aligned if possible.
  if (const ComplexType *CT = T->getAs<ComplexType>())
    T = CT->getElementType().getTypePtr();
  if (const EnumType *ET = T->getAs<EnumType>())
    T = ET->getDecl()->getIntegerType().getTypePtr();
  if (T->isSpecificBuiltinType(BuiltinType::Double) ||
      T->isSpecificBuiltinType(BuiltinType::LongLong) ||
      T->isSpecificBuiltinType(BuiltinType::ULongLong))
    // Don't increase the alignment if an alignment attribute was specified on a
    // typedef declaration.
    if (!TI.AlignIsRequired)
      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 {
  return std::max(getTypeAlign(T), getTargetInfo().getMinGlobalAlign());
}

/// getAlignOfGlobalVarInChars - Return the alignment in characters that
/// should be given to a global variable of the specified type.
CharUnits ASTContext::getAlignOfGlobalVarInChars(QualType T) const {
  return toCharUnitsFromBits(getAlignOfGlobalVar(T));
}

CharUnits ASTContext::getOffsetOfBaseWithVBPtr(const CXXRecordDecl *RD) const {
  CharUnits Offset = CharUnits::Zero();
  const ASTRecordLayout *Layout = &getASTRecordLayout(RD);
  while (const CXXRecordDecl *Base = Layout->getBaseSharingVBPtr()) {
    Offset += Layout->getBaseClassOffset(Base);
    Layout = &getASTRecordLayout(Base);
  }
  return Offset;
}

/// 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) {
    for (const auto *I : OI->ivars())
      Ivars.push_back(I);
  } else {
    ObjCInterfaceDecl *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 ObjCInterfaceDecl *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 ObjCCategoryDecl *OC = dyn_cast<ObjCCategoryDecl>(CDecl)) {
    for (auto *Proto : OC->protocols()) {
      CollectInheritedProtocols(Proto, Protocols);
    }
  } else if (const ObjCProtocolDecl *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);
  }
}

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;
}

/// \brief Get the implementation of ObjCInterfaceDecl,or NULL 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;
}
/// \brief Get the implementation of ObjCCategoryDecl, or NULL 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;
}

/// \brief Set the implementation of ObjCInterfaceDecl.
void ASTContext::setObjCImplementation(ObjCInterfaceDecl *IFaceD,
                           ObjCImplementationDecl *ImplD) {
  assert(IFaceD && ImplD && "Passed null params");
  ObjCImpls[IFaceD] = ImplD;
}
/// \brief 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 ObjCInterfaceDecl *ID =
          dyn_cast<ObjCInterfaceDecl>(ND->getDeclContext()))
    return ID;
  if (const ObjCCategoryDecl *CD =
          dyn_cast<ObjCCategoryDecl>(ND->getDeclContext()))
    return CD->getClassInterface();
  if (const ObjCImplDecl *IMD =
          dyn_cast<ObjCImplDecl>(ND->getDeclContext()))
    return IMD->getClassInterface();

  return nullptr;
}

/// \brief Get the copy initialization expression of VarDecl,or NULL if
/// none exists.
Expr *ASTContext::getBlockVarCopyInits(const VarDecl*VD) {
  assert(VD && "Passed null params");
  assert(VD->hasAttr<BlocksAttr>() &&
         "getBlockVarCopyInits - not __block var");
  llvm::DenseMap<const VarDecl*, Expr*>::iterator
    I = BlockVarCopyInits.find(VD);
  return (I != BlockVarCopyInits.end()) ? cast<Expr>(I->second) : nullptr;
}

/// \brief Set the copy inialization expression of a block var decl.
void ASTContext::setBlockVarCopyInits(VarDecl*VD, Expr* Init) {
  assert(VD && Init && "Passed null params");
  assert(VD->hasAttr<BlocksAttr>() &&
         "setBlockVarCopyInits - not __block var");
  BlockVarCopyInits[VD] = Init;
}

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!");

  TypeSourceInfo *TInfo =
    (TypeSourceInfo*)BumpAlloc.Allocate(sizeof(TypeSourceInfo) + DataSize, 8);
  new (TInfo) TypeSourceInfo(T);
  return TInfo;
}

TypeSourceInfo *ASTContext::getTrivialTypeSourceInfo(QualType T,
                                                     SourceLocation L) const {
  TypeSourceInfo *DI = CreateTypeSourceInfo(T);
  DI->getTypeLoc().initialize(const_cast<ASTContext &>(*this), L);
  return DI;
}

const ASTRecordLayout &
ASTContext::getASTObjCInterfaceLayout(const ObjCInterfaceDecl *D) const {
  return getObjCLayout(D, nullptr);
}

const ASTRecordLayout &
ASTContext::getASTObjCImplementationLayout(
                                        const ObjCImplementationDecl *D) const {
  return getObjCLayout(D->getClassInterface(), D);
}

//===----------------------------------------------------------------------===//
//                   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);
  }

  ExtQuals *eq = new (*this, TypeAlignment) ExtQuals(baseType, canon, quals);
  ExtQualNodes.InsertNode(eq, insertPos);
  return QualType(eq, fastQuals);
}

QualType
ASTContext::getAddrSpaceQualType(QualType T, unsigned 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::getObjCGCQualType(QualType T,
                                       Qualifiers::GC GCAttr) const {
  QualType CanT = getCanonicalType(T);
  if (CanT.getObjCGCAttr() == GCAttr)
    return T;

  if (const PointerType *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);
}

const FunctionType *ASTContext::adjustFunctionType(const FunctionType *T,
                                                   FunctionType::ExtInfo Info) {
  if (T->getExtInfo() == Info)
    return T;

  QualType Result;
  if (const FunctionNoProtoType *FNPT = dyn_cast<FunctionNoProtoType>(T)) {
    Result = getFunctionNoProtoType(FNPT->getReturnType(), Info);
  } else {
    const FunctionProtoType *FPT = cast<FunctionProtoType>(T);
    FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
    EPI.ExtInfo = Info;
    Result = getFunctionType(FPT->getReturnType(), FPT->getParamTypes(), EPI);
  }

  return cast<FunctionType>(Result.getTypePtr());
}

void ASTContext::adjustDeducedFunctionResultType(FunctionDecl *FD,
                                                 QualType ResultType) {
  FD = FD->getMostRecentDecl();
  while (true) {
    const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>();
    FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
    FD->setType(getFunctionType(ResultType, FPT->getParamTypes(), EPI));
    if (FunctionDecl *Next = FD->getPreviousDecl())
      FD = Next;
    else
      break;
  }
  if (ASTMutationListener *L = getASTMutationListener())
    L->DeducedReturnType(FD, ResultType);
}

/// Get a function type and produce the equivalent function type with the
/// specified exception specification. Type sugar that can be present on a
/// declaration of a function with an exception specification is permitted
/// and preserved. Other type sugar (for instance, typedefs) is not.
static QualType getFunctionTypeWithExceptionSpec(
    ASTContext &Context, QualType Orig,
    const FunctionProtoType::ExceptionSpecInfo &ESI) {
  // Might have some parens.
  if (auto *PT = dyn_cast<ParenType>(Orig))
    return Context.getParenType(
        getFunctionTypeWithExceptionSpec(Context, PT->getInnerType(), ESI));

  // Might have a calling-convention attribute.
  if (auto *AT = dyn_cast<AttributedType>(Orig))
    return Context.getAttributedType(
        AT->getAttrKind(),
        getFunctionTypeWithExceptionSpec(Context, AT->getModifiedType(), ESI),
        getFunctionTypeWithExceptionSpec(Context, AT->getEquivalentType(),
                                         ESI));

  // Anything else must be a function type. Rebuild it with the new exception
  // specification.
  const FunctionProtoType *Proto = cast<FunctionProtoType>(Orig);
  return Context.getFunctionType(
      Proto->getReturnType(), Proto->getParamTypes(),
      Proto->getExtProtoInfo().withExceptionSpec(ESI));
}

void ASTContext::adjustExceptionSpec(
    FunctionDecl *FD, const FunctionProtoType::ExceptionSpecInfo &ESI,
    bool AsWritten) {
  // Update the type.
  QualType Updated =
      getFunctionTypeWithExceptionSpec(*this, 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(*this, 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;
  }
  ComplexType *New = new (*this, TypeAlignment) ComplexType(T, Canonical);
  Types.push_back(New);
  ComplexTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}

/// getPointerType - Return the uniqued reference to the type for a pointer to
/// the specified type.
QualType ASTContext::getPointerType(QualType T) const {
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  PointerType::Profile(ID, T);

  void *InsertPos = nullptr;
  if (PointerType *PT = PointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(PT, 0);

  // If the pointee type isn't canonical, this won't be a canonical type either,
  // so fill in the canonical type field.
  QualType Canonical;
  if (!T.isCanonical()) {
    Canonical = getPointerType(getCanonicalType(T));

    // Get the new insert position for the node we care about.
    PointerType *NewIP = PointerTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  PointerType *New = new (*this, TypeAlignment) PointerType(T, Canonical);
  Types.push_back(New);
  PointerTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}

QualType ASTContext::getAdjustedType(QualType Orig, QualType New) const {
  llvm::FoldingSetNodeID ID;
  AdjustedType::Profile(ID, Orig, New);
  void *InsertPos = nullptr;
  AdjustedType *AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (AT)
    return QualType(AT, 0);

  QualType Canonical = getCanonicalType(New);

  // Get the new insert position for the node we care about.
  AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  assert(!AT && "Shouldn't be in the map!");

  AT = new (*this, TypeAlignment)
      AdjustedType(Type::Adjusted, Orig, New, Canonical);
  Types.push_back(AT);
  AdjustedTypes.InsertNode(AT, InsertPos);
  return QualType(AT, 0);
}

QualType ASTContext::getDecayedType(QualType 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);

  llvm::FoldingSetNodeID ID;
  AdjustedType::Profile(ID, T, Decayed);
  void *InsertPos = nullptr;
  AdjustedType *AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (AT)
    return QualType(AT, 0);

  QualType Canonical = getCanonicalType(Decayed);

  // Get the new insert position for the node we care about.
  AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
  assert(!AT && "Shouldn't be in the map!");

  AT = new (*this, TypeAlignment) DecayedType(T, Decayed, Canonical);
  Types.push_back(AT);
  AdjustedTypes.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;
  }
  BlockPointerType *New
    = new (*this, TypeAlignment) BlockPointerType(T, Canonical);
  Types.push_back(New);
  BlockPointerTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}

/// getLValueReferenceType - Return the uniqued reference to the type for an
/// lvalue reference to the specified type.
QualType
ASTContext::getLValueReferenceType(QualType T, bool SpelledAsLValue) const {
  assert(getCanonicalType(T) != OverloadTy &&
         "Unresolved overloaded function 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 ReferenceType *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;
  }

  LValueReferenceType *New
    = new (*this, TypeAlignment) LValueReferenceType(T, Canonical,
                                                     SpelledAsLValue);
  Types.push_back(New);
  LValueReferenceTypes.InsertNode(New, InsertPos);

  return QualType(New, 0);
}

/// getRValueReferenceType - Return the uniqued reference to the type for an
/// rvalue reference to the specified type.
QualType ASTContext::getRValueReferenceType(QualType T) const {
  // 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 ReferenceType *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;
  }

  RValueReferenceType *New
    = new (*this, TypeAlignment) RValueReferenceType(T, Canonical);
  Types.push_back(New);
  RValueReferenceTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}

/// getMemberPointerType - Return the uniqued reference to the type for a
/// member pointer to the specified type, in the specified class.
QualType ASTContext::getMemberPointerType(QualType T, const Type *Cls) const {
  // Unique pointers, to guarantee there is only one pointer of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  MemberPointerType::Profile(ID, T, Cls);

  void *InsertPos = nullptr;
  if (MemberPointerType *PT =
      MemberPointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(PT, 0);

  // If the pointee or class type isn't canonical, this won't be a canonical
  // type either, so fill in the canonical type field.
  QualType Canonical;
  if (!T.isCanonical() || !Cls->isCanonicalUnqualified()) {
    Canonical = getMemberPointerType(getCanonicalType(T),getCanonicalType(Cls));

    // Get the new insert position for the node we care about.
    MemberPointerType *NewIP =
      MemberPointerTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }
  MemberPointerType *New
    = new (*this, TypeAlignment) MemberPointerType(T, Cls, Canonical);
  Types.push_back(New);
  MemberPointerTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}

/// getConstantArrayType - Return the unique reference to the type for an
/// array of the specified element type.
QualType ASTContext::getConstantArrayType(QualType EltTy,
                                          const llvm::APInt &ArySizeIn,
                                          ArrayType::ArraySizeModifier ASM,
                                          unsigned IndexTypeQuals) const {
  assert((EltTy->isDependentType() ||
          EltTy->isIncompleteType() || EltTy->isConstantSizeType()) &&
         "Constant array of VLAs is illegal!");

  // Convert the array size into a canonical width matching the pointer size for
  // the target.
  llvm::APInt ArySize(ArySizeIn);
  ArySize =
    ArySize.zextOrTrunc(Target->getPointerWidth(getTargetAddressSpace(EltTy)));

  llvm::FoldingSetNodeID ID;
  ConstantArrayType::Profile(ID, EltTy, ArySize, 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, this won't
  // be a canonical type either, so fill in the canonical type field.
  QualType Canon;
  if (!EltTy.isCanonical() || EltTy.hasLocalQualifiers()) {
    SplitQualType canonSplit = getCanonicalType(EltTy).split();
    Canon = getConstantArrayType(QualType(canonSplit.Ty, 0), ArySize,
                                 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;
  }

  ConstantArrayType *New = new(*this,TypeAlignment)
    ConstantArrayType(EltTy, Canon, ArySize, 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.def"
    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::ExtVector:
  case Type::DependentSizedExtVector:
  case Type::ObjCObject:
  case Type::ObjCInterface:
  case Type::ObjCObjectPointer:
  case Type::Record:
  case Type::Enum:
  case Type::UnresolvedUsing:
  case Type::TypeOfExpr:
  case Type::TypeOf:
  case Type::Decltype:
  case Type::UnaryTransform:
  case Type::DependentName:
  case Type::InjectedClassName:
  case Type::TemplateSpecialization:
  case Type::DependentTemplateSpecialization:
  case Type::TemplateTypeParm:
  case Type::SubstTemplateTypeParmPack:
  case Type::Auto:
  case Type::PackExpansion:
    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 LValueReferenceType *lv = cast<LValueReferenceType>(ty);
    result = getLValueReferenceType(
                 getVariableArrayDecayedType(lv->getPointeeType()),
                                    lv->isSpelledAsLValue());
    break;
  }

  case Type::RValueReference: {
    const RValueReferenceType *lv = cast<RValueReferenceType>(ty);
    result = getRValueReferenceType(
                 getVariableArrayDecayedType(lv->getPointeeType()));
    break;
  }

  case Type::Atomic: {
    const AtomicType *at = cast<AtomicType>(ty);
    result = getAtomicType(getVariableArrayDecayedType(at->getValueType()));
    break;
  }

  case Type::ConstantArray: {
    const ConstantArrayType *cat = cast<ConstantArrayType>(ty);
    result = getConstantArrayType(
                 getVariableArrayDecayedType(cat->getElementType()),
                                  cat->getSize(),
                                  cat->getSizeModifier(),
                                  cat->getIndexTypeCVRQualifiers());
    break;
  }

  case Type::DependentSizedArray: {
    const DependentSizedArrayType *dat = cast<DependentSizedArrayType>(ty);
    result = getDependentSizedArrayType(
                 getVariableArrayDecayedType(dat->getElementType()),
                                        dat->getSizeExpr(),
                                        dat->getSizeModifier(),
                                        dat->getIndexTypeCVRQualifiers(),
                                        dat->getBracketsRange());
    break;
  }

  // Turn incomplete types into [*] types.
  case Type::IncompleteArray: {
    const IncompleteArrayType *iat = cast<IncompleteArrayType>(ty);
    result = getVariableArrayType(
                 getVariableArrayDecayedType(iat->getElementType()),
                                  /*size*/ nullptr,
                                  ArrayType::Normal,
                                  iat->getIndexTypeCVRQualifiers(),
                                  SourceRange());
    break;
  }

  // Turn VLA types into [*] types.
  case Type::VariableArray: {
    const VariableArrayType *vat = cast<VariableArrayType>(ty);
    result = getVariableArrayType(
                 getVariableArrayDecayedType(vat->getElementType()),
                                  /*size*/ nullptr,
                                  ArrayType::Star,
                                  vat->getIndexTypeCVRQualifiers(),
                                  vat->getBracketsRange());
    break;
  }
  }

  // Apply the top-level qualifiers from the original.
  return getQualifiedType(result, split.Quals);
}

/// getVariableArrayType - Returns a non-unique reference to the type for a
/// variable array of the specified element type.
QualType ASTContext::getVariableArrayType(QualType EltTy,
                                          Expr *NumElts,
                                          ArrayType::ArraySizeModifier ASM,
                                          unsigned IndexTypeQuals,
                                          SourceRange Brackets) const {
  // Since we don't unique expressions, it isn't possible to unique VLA's
  // that have an expression provided for their size.
  QualType Canon;

  // Be sure to pull qualifiers off the element type.
  if (!EltTy.isCanonical() || EltTy.hasLocalQualifiers()) {
    SplitQualType canonSplit = getCanonicalType(EltTy).split();
    Canon = getVariableArrayType(QualType(canonSplit.Ty, 0), NumElts, ASM,
                                 IndexTypeQuals, Brackets);
    Canon = getQualifiedType(Canon, canonSplit.Quals);
  }

  VariableArrayType *New = new(*this, TypeAlignment)
    VariableArrayType(EltTy, Canon, NumElts, ASM, IndexTypeQuals, Brackets);

  VariableArrayTypes.push_back(New);
  Types.push_back(New);
  return QualType(New, 0);
}

/// getDependentSizedArrayType - Returns a non-unique reference to
/// the type for a dependently-sized array of the specified element
/// type.
QualType ASTContext::getDependentSizedArrayType(QualType elementType,
                                                Expr *numElements,
                                                ArrayType::ArraySizeModifier ASM,
                                                unsigned elementTypeQuals,
                                                SourceRange brackets) const {
  assert((!numElements || numElements->isTypeDependent() ||
          numElements->isValueDependent()) &&
         "Size must be type- or value-dependent!");

  // Dependently-sized array types that do not have a specified number
  // of elements will have their sizes deduced from a dependent
  // initializer.  We do no canonicalization here at all, which is okay
  // because they can't be used in most locations.
  if (!numElements) {
    DependentSizedArrayType *newType
      = new (*this, TypeAlignment)
          DependentSizedArrayType(*this, elementType, QualType(),
                                  numElements, ASM, elementTypeQuals,
                                  brackets);
    Types.push_back(newType);
    return QualType(newType, 0);
  }

  // Otherwise, we actually build a new type every time, but we
  // also build a canonical type.

  SplitQualType canonElementType = getCanonicalType(elementType).split();

  void *insertPos =