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/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
};

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;
}
} // unnamed 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) {
        Raw.setRaw(RC);
        Raw.setKind(RawCommentAndCacheFlags::FromDecl);
      } 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.data(),
                                                ExpandedTypes.size(),
                                                ExpandedTInfos.data());
      } 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.data(),
                                                       CanonParams.size(),
                                                       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::GenericAArch64:
  case TargetCXXABI::GenericItanium:
    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, // cuda_device
      5, // cuda_constant
      6  // 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), Float128StubDecl(nullptr),
    BuiltinVaListDecl(nullptr),
    ObjCIdDecl(nullptr), ObjCSelDecl(nullptr), ObjCClassDecl(nullptr),
    ObjCProtocolClassDecl(nullptr), BOOLDecl(nullptr),
    CFConstantStringTypeDecl(nullptr), ObjCInstanceTypeDecl(nullptr),
    FILEDecl(nullptr),
    jmp_bufDecl(nullptr), sigjmp_bufDecl(nullptr), ucontext_tDecl(nullptr),
    BlockDescriptorType(nullptr), BlockDescriptorExtendedType(nullptr),
    cudaConfigureCallDecl(nullptr),
    NullTypeSourceInfo(QualType()),
    FirstLocalImport(), LastLocalImport(),
    SourceMgr(SM), LangOpts(LOpts),
    AddrSpaceMap(nullptr), Target(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 (DeallocationMap::const_iterator I = Deallocations.begin(),
           E = Deallocations.end(); I != E; ++I)
    for (unsigned J = 0, N = I->second.size(); J != N; ++J)
      (I->first)((I->second)[J]);

  // 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();

  llvm::DeleteContainerSeconds(MangleNumberingContexts);
}

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

void ASTContext::AddDeallocation(void (*Callback)(void*), void *Data) {
  Deallocations[Callback].push_back(Data);
}

void
ASTContext::setExternalSource(IntrusiveRefCntPtr<ExternalASTSource> Source) {
  ExternalSource = 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();
}

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();
  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;
}

TypeDecl *ASTContext::getFloat128StubType() const {
  assert(LangOpts.CPlusPlus && "should only be called for c++");
  if (!Float128StubDecl)
    Float128StubDecl = buildImplicitRecord("__float128");

  return Float128StubDecl;
}

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) {
  assert((!this->Target || this->Target == &Target) &&
         "Incorrect target reinitialization");
  assert(VoidTy.isNull() && "Context reinitialized?");

  this->Target = &Target;

  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, 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);

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

  // Builtin types for 'id', 'Class', and 'SEL'.
  InitBuiltinType(ObjCBuiltinIdTy, BuiltinType::ObjCId);
  InitBuiltinType(ObjCBuiltinClassTy, BuiltinType::ObjCClass);
  InitBuiltinType(ObjCBuiltinSelTy, BuiltinType::ObjCSel);

  if (LangOpts.OpenCL) {
    InitBuiltinType(OCLImage1dTy, BuiltinType::OCLImage1d);
    InitBuiltinType(OCLImage1dArrayTy, BuiltinType::OCLImage1dArray);
    InitBuiltinType(OCLImage1dBufferTy, BuiltinType::OCLImage1dBuffer);
    InitBuiltinType(OCLImage2dTy, BuiltinType::OCLImage2d);
    InitBuiltinType(OCLImage2dArrayTy, BuiltinType::OCLImage2dArray);
    InitBuiltinType(OCLImage3dTy, BuiltinType::OCLImage3d);

    InitBuiltinType(OCLSamplerTy, BuiltinType::OCLSampler);
    InitBuiltinType(OCLEventTy, BuiltinType::OCLEvent);
  }

  // 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.
  VaListTagTy = QualType();
}

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();
}

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();
  }
}

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())
          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::RoundUpToAlignment(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);
  std::pair<uint64_t, unsigned> Info = getTypeInfo(T);
  return std::make_pair(toCharUnitsFromBits(Info.first),
                        toCharUnitsFromBits(Info.second));
}

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

std::pair<uint64_t, unsigned> ASTContext::getTypeInfo(const Type *T) const {
  TypeInfoMap::iterator it = MemoizedTypeInfo.find(T);
  if (it != MemoizedTypeInfo.end())
    return it->second;

  std::pair<uint64_t, unsigned> Info = getTypeInfoImpl(T);
  MemoizedTypeInfo.insert(std::make_pair(T, Info));
  return Info;
}

/// 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.
std::pair<uint64_t, unsigned>
ASTContext::getTypeInfoImpl(const Type *T) const {
  uint64_t Width=0;
  unsigned Align=8;
  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);

    std::pair<uint64_t, unsigned> EltInfo = getTypeInfo(CAT->getElementType());
    uint64_t Size = CAT->getSize().getZExtValue();
    assert((Size == 0 || EltInfo.first <= (uint64_t)(-1)/Size) &&
           "Overflow in array type bit size evaluation");
    Width = EltInfo.first*Size;
    Align = EltInfo.second;
    if (!getTargetInfo().getCXXABI().isMicrosoft() ||
        getTargetInfo().getPointerWidth(0) == 64)
      Width = llvm::RoundUpToAlignment(Width, Align);
    break;
  }
  case Type::ExtVector:
  case Type::Vector: {
    const VectorType *VT = cast<VectorType>(T);
    std::pair<uint64_t, unsigned> EltInfo = getTypeInfo(VT->getElementType());
    Width = EltInfo.first*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::RoundUpToAlignment(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::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::OCLImage1d:
    case BuiltinType::OCLImage1dArray:
    case BuiltinType::OCLImage1dBuffer:
    case BuiltinType::OCLImage2d:
    case BuiltinType::OCLImage2dArray:
    case BuiltinType::OCLImage3d:
      // 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.
    std::pair<uint64_t, unsigned> EltInfo =
      getTypeInfo(cast<ComplexType>(T)->getElementType());
    Width = EltInfo.first*2;
    Align = EltInfo.second;
    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))
      return getTypeInfo(ET->getDecl()->getIntegerType());

    const RecordType *RT = cast<RecordType>(TT);
    const ASTRecordLayout &Layout = getASTRecordLayout(RT->getDecl());
    Width = toBits(Layout.getSize());
    Align = toBits(Layout.getAlignment());
    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();
    std::pair<uint64_t, unsigned> 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;
    else
      Align = Info.second;
    Width = Info.first;
    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.
    std::pair<uint64_t, unsigned> Info
      = getTypeInfo(cast<AtomicType>(T)->getValueType());
    Width = Info.first;
    Align = Info.second;

    // 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);
    }
  }

  }

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

/// 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 {
  unsigned ABIAlign = getTypeAlign(T);

  if (Target->getTriple().getArch() == llvm::Triple::xcore)
    return ABIAlign;  // Never overalign on XCore.

  const TypedefType *TT = T->getAs<TypedefType>();

  // Double and long long should be naturally aligned if possible.
  T = T->getBaseElementTypeUnsafe();
  if (const ComplexType *CT = T->getAs<ComplexType>())
    T = CT->getElementType().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 (!TT || !TT->getDecl()->getMaxAlignment())
      return std::max(ABIAlign, (unsigned)getTypeSize(T));

  return ABIAlign;
}

/// 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));
}

/// 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()) {
      Protocols.insert(Proto->getCanonicalDecl());
      for (auto *P : Proto->protocols()) {
        Protocols.insert(P->getCanonicalDecl());
        CollectInheritedProtocols(P, 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()) {
      Protocols.insert(Proto->getCanonicalDecl());
      for (const auto *P : Proto->protocols())
        CollectInheritedProtocols(P, Protocols);
    }
  } else if (const ObjCProtocolDecl *OP = dyn_cast<ObjCProtocolDecl>(CDecl)) {
    for (auto *Proto : OP->protocols()) {
      Protocols.insert(Proto->getCanonicalDecl());
      for (const auto *P : Proto->protocols())
        CollectInheritedProtocols(P, 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 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);
}

/// 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:
    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 = nullptr;
  llvm::FoldingSetNodeID ID;
  DependentSizedArrayType::Profile(ID, *this,
                                   QualType(canonElementType.Ty, 0),
                                   ASM, elementTypeQuals, numElements);

  // Look for an existing type with these properties.
  DependentSizedArrayType *canonTy =
    DependentSizedArrayTypes.FindNodeOrInsertPos(ID, insertPos);

  // If we don't have one, build one.
  if (!canonTy) {
    canonTy = new (*this, TypeAlignment)
      DependentSizedArrayType(*this, QualType(canonElementType.Ty, 0),
                              QualType(), numElements, ASM, elementTypeQuals,
                              brackets);
    DependentSizedArrayTypes.InsertNode(canonTy, insertPos);
    Types.push_back(canonTy);
  }

  // Apply qualifiers from the element type to the array.
  QualType canon = getQualifiedType(QualType(canonTy,0),
                                    canonElementType.Quals);

  // If we didn't need extra canonicalization for the element type,
  // then just use that as our result.
  if (QualType(canonElementType.Ty, 0) == elementType)
    return canon;

  // Otherwise, we need to build a type which follows the spelling
  // of the element type.
  DependentSizedArrayType *sugaredType
    = new (*this, TypeAlignment)
        DependentSizedArrayType(*this, elementType, canon, numElements,
                                ASM, elementTypeQuals, brackets);
  Types.push_back(sugaredType);
  return QualType(sugaredType, 0);
}

QualType ASTContext::getIncompleteArrayType(QualType elementType,
                                            ArrayType::ArraySizeModifier ASM,
                                            unsigned elementTypeQuals) const {
  llvm::FoldingSetNodeID ID;
  IncompleteArrayType::Profile(ID, elementType, ASM, elementTypeQuals);

  void *insertPos = nullptr;
  if (IncompleteArrayType *iat =
       IncompleteArrayTypes.FindNodeOrInsertPos(ID, insertPos))
    return QualType(iat, 0);

  // If the element type isn't canonical, this won't be a canonical type
  // either, so fill in the canonical type field.  We also have to pull
  // qualifiers off the element type.
  QualType canon;

  if (!elementType.isCanonical() || elementType.hasLocalQualifiers()) {
    SplitQualType canonSplit = getCanonicalType(elementType).split();
    canon = getIncompleteArrayType(QualType(canonSplit.Ty, 0),
                                   ASM, elementTypeQuals);
    canon = getQualifiedType(canon, canonSplit.Quals);

    // Get the new insert position for the node we care about.
    IncompleteArrayType *existing =
      IncompleteArrayTypes.FindNodeOrInsertPos(ID, insertPos);
    assert(!existing && "Shouldn't be in the map!"); (void) existing;
  }

  IncompleteArrayType *newType = new (*this, TypeAlignment)
    IncompleteArrayType(elementType, canon, ASM, elementTypeQuals);

  IncompleteArrayTypes.InsertNode(newType, insertPos);
  Types.push_back(newType);
  return QualType(newType, 0);
}

/// getVectorType - Return the unique reference to a vector type of
/// the specified element type and size. VectorType must be a built-in type.
QualType ASTContext::getVectorType(QualType vecType, unsigned NumElts,
                                   VectorType::VectorKind VecKind) const {
  assert(vecType->isBuiltinType());

  // Check if we've already instantiated a vector of this type.
  llvm::FoldingSetNodeID ID;
  VectorType::Profile(ID, vecType, NumElts, Type::Vector, VecKind);

  void *InsertPos = nullptr;
  if (VectorType *VTP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(VTP, 0);

  // If the element type isn't canonical, this won't be a canonical type either,
  // so fill in the canonical type field.
  QualType Canonical;
  if (!vecType.isCanonical()) {
    Canonical = getVectorType(getCanonicalType(vecType), NumElts, VecKind);

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

/// getExtVectorType - Return the unique reference to an extended vector type of
/// the specified element type and size. VectorType must be a built-in type.
QualType
ASTContext::getExtVectorType(QualType vecType, unsigned NumElts) const {
  assert(vecType->isBuiltinType() || vecType->isDependentType());

  // Check if we've already instantiated a vector of this type.
  llvm::FoldingSetNodeID ID;
  VectorType::Profile(ID, vecType, NumElts, Type::ExtVector,
                      VectorType::GenericVector);
  void *InsertPos = nullptr;
  if (VectorType *VTP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(VTP, 0);

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

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

QualType
ASTContext::getDependentSizedExtVectorType(QualType vecType,
                                           Expr *SizeExpr,
                                           SourceLocation AttrLoc) const {
  llvm::FoldingSetNodeID ID;
  DependentSizedExtVectorType::Profile(ID, *this, getCanonicalType(vecType),
                                       SizeExpr);

  void *InsertPos = nullptr;
  DependentSizedExtVectorType *Canon
    = DependentSizedExtVectorTypes.FindNodeOrInsertPos(ID, InsertPos);
  DependentSizedExtVectorType *New;
  if (Canon) {
    // We already have a canonical version of this array type; use it as
    // the canonical type for a newly-built type.
    New = new (*this, TypeAlignment)
      DependentSizedExtVectorType(*this, vecType, QualType(Canon, 0),
                                  SizeExpr, AttrLoc);
  } else {
    QualType CanonVecTy = getCanonicalType(vecType);
    if (CanonVecTy == vecType) {
      New = new (*this, TypeAlignment)
        DependentSizedExtVectorType(*this, vecType, QualType(), SizeExpr,
                                    AttrLoc);

      DependentSizedExtVectorType *CanonCheck
        = DependentSizedExtVectorTypes.FindNodeOrInsertPos(ID, InsertPos);
      assert(!CanonCheck && "Dependent-sized ext_vector canonical type broken");
      (void)CanonCheck;
      DependentSizedExtVectorTypes.InsertNode(New, InsertPos);
    } else {
      QualType Canon = getDependentSizedExtVectorType(CanonVecTy, SizeExpr,
                                                      SourceLocation());
      New = new (*this, TypeAlignment)
        DependentSizedExtVectorType(*this, vecType, Canon, SizeExpr, AttrLoc);
    }
  }

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

/// getFunctionNoProtoType - Return a K&R style C function type like 'int()'.
///
QualType
ASTContext::getFunctionNoProtoType(QualType ResultTy,
                                   const FunctionType::ExtInfo &Info) const {
  const CallingConv CallConv = Info.getCC();

  // Unique functions, to guarantee there is only one function of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  FunctionNoProtoType::Profile(ID, ResultTy, Info);

  void *InsertPos = nullptr;
  if (FunctionNoProtoType *FT =
        FunctionNoProtoTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(FT, 0);

  QualType Canonical;
  if (!ResultTy.isCanonical()) {
    Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy), Info);

    // Get the new insert position for the node we care about.
    FunctionNoProtoType *NewIP =
      FunctionNoProtoTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }

  FunctionProtoType::ExtInfo newInfo = Info.withCallingConv(CallConv);
  FunctionNoProtoType *New = new (*this, TypeAlignment)
    FunctionNoProtoType(ResultTy, Canonical, newInfo);
  Types.push_back(New);
  FunctionNoProtoTypes.InsertNode(New, InsertPos);
  return QualType(New, 0);
}

/// \brief Determine whether \p T is canonical as the result type of a function.
static bool isCanonicalResultType(QualType T) {
  return T.isCanonical() &&
         (T.getObjCLifetime() == Qualifiers::OCL_None ||
          T.getObjCLifetime() == Qualifiers::OCL_ExplicitNone);
}

QualType
ASTContext::getFunctionType(QualType ResultTy, ArrayRef<QualType> ArgArray,
                            const FunctionProtoType::ExtProtoInfo &EPI) const {
  size_t NumArgs = ArgArray.size();

  // Unique functions, to guarantee there is only one function of a particular
  // structure.
  llvm::FoldingSetNodeID ID;
  FunctionProtoType::Profile(ID, ResultTy, ArgArray.begin(), NumArgs, EPI,
                             *this);

  void *InsertPos = nullptr;
  if (FunctionProtoType *FTP =
        FunctionProtoTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(FTP, 0);

  // Determine whether the type being created is already canonical or not.
  bool isCanonical =
    EPI.ExceptionSpecType == EST_None && isCanonicalResultType(ResultTy) &&
    !EPI.HasTrailingReturn;
  for (unsigned i = 0; i != NumArgs && isCanonical; ++i)
    if (!ArgArray[i].isCanonicalAsParam())
      isCanonical = false;

  // If this type isn't canonical, get the canonical version of it.
  // The exception spec is not part of the canonical type.
  QualType Canonical;
  if (!isCanonical) {
    SmallVector<QualType, 16> CanonicalArgs;
    CanonicalArgs.reserve(NumArgs);
    for (unsigned i = 0; i != NumArgs; ++i)
      CanonicalArgs.push_back(getCanonicalParamType(ArgArray[i]));

    FunctionProtoType::ExtProtoInfo CanonicalEPI = EPI;
    CanonicalEPI.HasTrailingReturn = false;
    CanonicalEPI.ExceptionSpecType = EST_None;
    CanonicalEPI.NumExceptions = 0;

    // Result types do not have ARC lifetime qualifiers.
    QualType CanResultTy = getCanonicalType(ResultTy);
    if (ResultTy.getQualifiers().hasObjCLifetime()) {
      Qualifiers Qs = CanResultTy.getQualifiers();
      Qs.removeObjCLifetime();
      CanResultTy = getQualifiedType(CanResultTy.getUnqualifiedType(), Qs);
    }

    Canonical = getFunctionType(CanResultTy, CanonicalArgs, CanonicalEPI);

    // Get the new insert position for the node we care about.
    FunctionProtoType *NewIP =
      FunctionProtoTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!NewIP && "Shouldn't be in the map!"); (void)NewIP;
  }

  // FunctionProtoType objects are allocated with extra bytes after
  // them for three variable size arrays at the end:
  //  - parameter types
  //  - exception types
  //  - consumed-arguments flags
  // Instead of the exception types, there could be a noexcept
  // expression, or information used to resolve the exception
  // specification.
  size_t Size = sizeof(FunctionProtoType) +
                NumArgs * sizeof(QualType);
  if (EPI.ExceptionSpecType == EST_Dynamic) {
    Size += EPI.NumExceptions * sizeof(QualType);
  } else if (EPI.ExceptionSpecType == EST_ComputedNoexcept) {
    Size += sizeof(Expr*);
  } else if (EPI.ExceptionSpecType == EST_Uninstantiated) {
    Size += 2 * sizeof(FunctionDecl*);
  } else if (EPI.ExceptionSpecType == EST_Unevaluated) {
    Size += sizeof(FunctionDecl*);
  }
  if (EPI.ConsumedParameters)
    Size += NumArgs * sizeof(bool);

  FunctionProtoType *FTP = (FunctionProtoType*) Allocate(Size, TypeAlignment);
  FunctionProtoType::ExtProtoInfo newEPI = EPI;
  new (FTP) FunctionProtoType(ResultTy, ArgArray, Canonical, newEPI);
  Types.push_back(FTP);
  FunctionProtoTypes.InsertNode(FTP, InsertPos);
  return QualType(FTP, 0);
}

#ifndef NDEBUG
static bool NeedsInjectedClassNameType(const RecordDecl *D) {
  if (!isa<CXXRecordDecl>(D)) return false;
  const CXXRecordDecl *RD = cast<CXXRecordDecl>(D);
  if (isa<ClassTemplatePartialSpecializationDecl>(RD))
    return true;
  if (RD->getDescribedClassTemplate() &&
      !isa<ClassTemplateSpecializationDecl>(RD))
    return true;
  return false;
}
#endif

/// getInjectedClassNameType - Return the unique reference to the
/// injected class name type for the specified templated declaration.
QualType ASTContext::getInjectedClassNameType(CXXRecordDecl *Decl,
                                              QualType TST) const {
  assert(NeedsInjectedClassNameType(Decl));
  if (Decl->TypeForDecl) {
    assert(isa<InjectedClassNameType>(Decl->TypeForDecl));
  } else if (CXXRecordDecl *PrevDecl = Decl->getPreviousDecl()) {
    assert(PrevDecl->TypeForDecl && "previous declaration has no type");
    Decl->TypeForDecl = PrevDecl->TypeForDecl;
    assert(isa<InjectedClassNameType>(Decl->TypeForDecl));
  } else {
    Type *newType =
      new (*this, TypeAlignment) InjectedClassNameType(Decl, TST);
    Decl->TypeForDecl = newType;
    Types.push_back(newType);
  }
  return QualType(Decl->TypeForDecl, 0);
}

/// getTypeDeclType - Return the unique reference to the type for the
/// specified type declaration.
QualType ASTContext::getTypeDeclTypeSlow(const TypeDecl *Decl) const {
  assert(Decl && "Passed null for Decl param");
  assert(!Decl->TypeForDecl && "TypeForDecl present in slow case");

  if (const TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Decl))
    return getTypedefType(Typedef);

  assert(!isa<TemplateTypeParmDecl>(Decl) &&
         "Template type parameter types are always available.");

  if (const RecordDecl *Record = dyn_cast<RecordDecl>(Decl)) {
    assert(Record->isFirstDecl() && "struct/union has previous declaration");
    assert(!NeedsInjectedClassNameType(Record));
    return getRecordType(Record);
  } else if (const EnumDecl *Enum = dyn_cast<EnumDecl>(Decl)) {
    assert(Enum->isFirstDecl() && "enum has previous declaration");
    return getEnumType(Enum);
  } else if (const UnresolvedUsingTypenameDecl *Using =
               dyn_cast<UnresolvedUsingTypenameDecl>(Decl)) {
    Type *newType = new (*this, TypeAlignment) UnresolvedUsingType(Using);
    Decl->TypeForDecl = newType;
    Types.push_back(newType);
  } else
    llvm_unreachable("TypeDecl without a type?");

  return QualType(Decl->TypeForDecl, 0);
}

/// getTypedefType - Return the unique reference to the type for the
/// specified typedef name decl.
QualType
ASTContext::getTypedefType(const TypedefNameDecl *Decl,
                           QualType Canonical) const {
  if (Decl->TypeForDecl) return QualType(Decl->TypeForDecl, 0);

  if (Canonical.isNull())
    Canonical = getCanonicalType(Decl->getUnderlyingType());
  TypedefType *newType = new(*this, TypeAlignment)
    TypedefType(Type::Typedef, Decl, Canonical);
  Decl->TypeForDecl = newType;
  Types.push_back(newType);
  return QualType(newType, 0);
}

QualType ASTContext::getRecordType(const RecordDecl *Decl) const {
  if (Decl->TypeForDecl) return QualType(Decl->TypeForDecl, 0);

  if (const RecordDecl *PrevDecl = Decl->getPreviousDecl())
    if (PrevDecl->TypeForDecl)
      return QualType(Decl->TypeForDecl = PrevDecl->TypeForDecl, 0);

  RecordType *newType = new (*this, TypeAlignment) RecordType(Decl);
  Decl->TypeForDecl = newType;
  Types.push_back(newType);
  return QualType(newType, 0);
}

QualType ASTContext::getEnumType(const EnumDecl *Decl) const {
  if (Decl->TypeForDecl) return QualType(Decl->TypeForDecl, 0);

  if (const EnumDecl *PrevDecl = Decl->getPreviousDecl())
    if (PrevDecl->TypeForDecl)
      return QualType(Decl->TypeForDecl = PrevDecl->TypeForDecl, 0);

  EnumType *newType = new (*this, TypeAlignment) EnumType(Decl);
  Decl->TypeForDecl = newType;
  Types.push_back(newType);
  return QualType(newType, 0);
}

QualType ASTContext::getAttributedType(AttributedType::Kind attrKind,
                                       QualType modifiedType,
                                       QualType equivalentType) {
  llvm::FoldingSetNodeID id;
  AttributedType::Profile(id, attrKind, modifiedType, equivalentType);

  void *insertPos = nullptr;
  AttributedType *type = AttributedTypes.FindNodeOrInsertPos(id, insertPos);
  if (type) return QualType(type, 0);

  QualType canon = getCanonicalType(equivalentType);
  type = new (*this, TypeAlignment)
           AttributedType(canon, attrKind, modifiedType, equivalentType);

  Types.push_back(type);
  AttributedTypes.InsertNode(type, insertPos);

  return QualType(type, 0);
}


/// \brief Retrieve a substitution-result type.
QualType
ASTContext::getSubstTemplateTypeParmType(const TemplateTypeParmType *Parm,
                                         QualType Replacement) const {
  assert(Replacement.isCanonical()
         && "replacement types must always be canonical");

  llvm::FoldingSetNodeID ID;
  SubstTemplateTypeParmType::Profile(ID, Parm, Replacement);
  void *InsertPos = nullptr;
  SubstTemplateTypeParmType *SubstParm
    = SubstTemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);

  if (!SubstParm) {
    SubstParm = new (*this, TypeAlignment)
      SubstTemplateTypeParmType(Parm, Replacement);
    Types.push_back(SubstParm);
    SubstTemplateTypeParmTypes.InsertNode(SubstParm, InsertPos);
  }

  return QualType(SubstParm, 0);
}

/// \brief Retrieve a
QualType ASTContext::getSubstTemplateTypeParmPackType(
                                          const TemplateTypeParmType *Parm,
                                              const TemplateArgument &ArgPack) {
#ifndef NDEBUG
  for (TemplateArgument::pack_iterator P = ArgPack.pack_begin(),
                                    PEnd = ArgPack.pack_end();
       P != PEnd; ++P) {
    assert(P->getKind() == TemplateArgument::Type &&"Pack contains a non-type");
    assert(P->getAsType().isCanonical() && "Pack contains non-canonical type");
  }
#endif

  llvm::FoldingSetNodeID ID;
  SubstTemplateTypeParmPackType::Profile(ID, Parm, ArgPack);
  void *InsertPos = nullptr;
  if (SubstTemplateTypeParmPackType *SubstParm
        = SubstTemplateTypeParmPackTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(SubstParm, 0);

  QualType Canon;
  if (!Parm->isCanonicalUnqualified()) {
    Canon = getCanonicalType(QualType(Parm, 0));
    Canon = getSubstTemplateTypeParmPackType(cast<TemplateTypeParmType>(Canon),
                                             ArgPack);
    SubstTemplateTypeParmPackTypes.FindNodeOrInsertPos(ID, InsertPos);
  }

  SubstTemplateTypeParmPackType *SubstParm
    = new (*this, TypeAlignment) SubstTemplateTypeParmPackType(Parm, Canon,
                                                               ArgPack);
  Types.push_back(SubstParm);
  SubstTemplateTypeParmTypes.InsertNode(SubstParm, InsertPos);
  return QualType(SubstParm, 0);
}

/// \brief Retrieve the template type parameter type for a template
/// parameter or parameter pack with the given depth, index, and (optionally)
/// name.
QualType ASTContext::getTemplateTypeParmType(unsigned Depth, unsigned Index,
                                             bool ParameterPack,
                                             TemplateTypeParmDecl *TTPDecl) const {
  llvm::FoldingSetNodeID ID;
  TemplateTypeParmType::Profile(ID, Depth, Index, ParameterPack, TTPDecl);
  void *InsertPos = nullptr;
  TemplateTypeParmType *TypeParm
    = TemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);

  if (TypeParm)
    return QualType(TypeParm, 0);

  if (TTPDecl) {
    QualType Canon = getTemplateTypeParmType(Depth, Index, ParameterPack);
    TypeParm = new (*this, TypeAlignment) TemplateTypeParmType(TTPDecl, Canon);

    TemplateTypeParmType *TypeCheck
      = TemplateTypeParmTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!TypeCheck && "Template type parameter canonical type broken");
    (void)TypeCheck;
  } else
    TypeParm = new (*this, TypeAlignment)
      TemplateTypeParmType(Depth, Index, ParameterPack);

  Types.push_back(TypeParm);
  TemplateTypeParmTypes.InsertNode(TypeParm, InsertPos);

  return QualType(TypeParm, 0);
}

TypeSourceInfo *
ASTContext::getTemplateSpecializationTypeInfo(TemplateName Name,
                                              SourceLocation NameLoc,
                                        const TemplateArgumentListInfo &Args,
                                              QualType Underlying) const {
  assert(!Name.getAsDependentTemplateName() &&
         "No dependent template names here!");
  QualType TST = getTemplateSpecializationType(Name, Args, Underlying);

  TypeSourceInfo *DI = CreateTypeSourceInfo(TST);
  TemplateSpecializationTypeLoc TL =
      DI->getTypeLoc().castAs<TemplateSpecializationTypeLoc>();
  TL.setTemplateKeywordLoc(SourceLocation());
  TL.setTemplateNameLoc(NameLoc);
  TL.setLAngleLoc(Args.getLAngleLoc());
  TL.setRAngleLoc(Args.getRAngleLoc());
  for (unsigned i = 0, e = TL.getNumArgs(); i != e; ++i)
    TL.setArgLocInfo(i, Args[i].getLocInfo());
  return DI;
}

QualType
ASTContext::getTemplateSpecializationType(TemplateName Template,
                                          const TemplateArgumentListInfo &Args,
                                          QualType Underlying) const {
  assert(!Template.getAsDependentTemplateName() &&
         "No dependent template names here!");

  unsigned NumArgs = Args.size();

  SmallVector<TemplateArgument, 4> ArgVec;
  ArgVec.reserve(NumArgs);
  for (unsigned i = 0; i != NumArgs; ++i)
    ArgVec.push_back(Args[i].getArgument());

  return getTemplateSpecializationType(Template, ArgVec.data(), NumArgs,
                                       Underlying);
}

#ifndef NDEBUG
static bool hasAnyPackExpansions(const TemplateArgument *Args,
                                 unsigned NumArgs) {
  for (unsigned I = 0; I != NumArgs; ++I)
    if (Args[I].isPackExpansion())
      return true;

  return true;
}
#endif

QualType
ASTContext::getTemplateSpecializationType(TemplateName Template,
                                          const TemplateArgument *Args,
                                          unsigned NumArgs,
                                          QualType Underlying) const {
  assert(!Template.getAsDependentTemplateName() &&
         "No dependent template names here!");
  // Look through qualified template names.
  if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
    Template = TemplateName(QTN->getTemplateDecl());

  bool IsTypeAlias =
    Template.getAsTemplateDecl() &&
    isa<TypeAliasTemplateDecl>(Template.getAsTemplateDecl());
  QualType CanonType;
  if (!Underlying.isNull())
    CanonType = getCanonicalType(Underlying);
  else {
    // We can get here with an alias template when the specialization contains
    // a pack expansion that does not match up with a parameter pack.
    assert((!IsTypeAlias || hasAnyPackExpansions(Args, NumArgs)) &&
           "Caller must compute aliased type");
    IsTypeAlias = false;
    CanonType = getCanonicalTemplateSpecializationType(Template, Args,
                                                       NumArgs);
  }

  // Allocate the (non-canonical) template specialization type, but don't
  // try to unique it: these types typically have location information that
  // we don't unique and don't want to lose.
  void *Mem = Allocate(sizeof(TemplateSpecializationType) +
                       sizeof(TemplateArgument) * NumArgs +
                       (IsTypeAlias? sizeof(QualType) : 0),
                       TypeAlignment);
  TemplateSpecializationType *Spec
    = new (Mem) TemplateSpecializationType(Template, Args, NumArgs, CanonType,
                                         IsTypeAlias ? Underlying : QualType());

  Types.push_back(Spec);
  return QualType(Spec, 0);
}

QualType
ASTContext::getCanonicalTemplateSpecializationType(TemplateName Template,
                                                   const TemplateArgument *Args,
                                                   unsigned NumArgs) const {
  assert(!Template.getAsDependentTemplateName() &&
         "No dependent template names here!");

  // Look through qualified template names.
  if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName())
    Template = TemplateName(QTN->getTemplateDecl());

  // Build the canonical template specialization type.
  TemplateName CanonTemplate = getCanonicalTemplateName(Template);
  SmallVector<TemplateArgument, 4> CanonArgs;
  CanonArgs.reserve(NumArgs);
  for (unsigned I = 0; I != NumArgs; ++I)
    CanonArgs.push_back(getCanonicalTemplateArgument(Args[I]));

  // Determine whether this canonical template specialization type already
  // exists.
  llvm::FoldingSetNodeID ID;
  TemplateSpecializationType::Profile(ID, CanonTemplate,
                                      CanonArgs.data(), NumArgs, *this);

  void *InsertPos = nullptr;
  TemplateSpecializationType *Spec
    = TemplateSpecializationTypes.FindNodeOrInsertPos(ID, InsertPos);

  if (!Spec) {
    // Allocate a new canonical template specialization type.
    void *Mem = Allocate((sizeof(TemplateSpecializationType) +
                          sizeof(TemplateArgument) * NumArgs),
                         TypeAlignment);
    Spec = new (Mem) TemplateSpecializationType(CanonTemplate,
                                                CanonArgs.data(), NumArgs,
                                                QualType(), QualType());
    Types.push_back(Spec);
    TemplateSpecializationTypes.InsertNode(Spec, InsertPos);
  }

  assert(Spec->isDependentType() &&
         "Non-dependent template-id type must have a canonical type");
  return QualType(Spec, 0);
}

QualType
ASTContext::getElaboratedType(ElaboratedTypeKeyword Keyword,
                              NestedNameSpecifier *NNS,
                              QualType NamedType) const {
  llvm::FoldingSetNodeID ID;
  ElaboratedType::Profile(ID, Keyword, NNS, NamedType);

  void *InsertPos = nullptr;
  ElaboratedType *T = ElaboratedTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);

  QualType Canon = NamedType;
  if (!Canon.isCanonical()) {
    Canon = getCanonicalType(NamedType);
    ElaboratedType *CheckT = ElaboratedTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!CheckT && "Elaborated canonical type broken");
    (void)CheckT;
  }

  T = new (*this) ElaboratedType(Keyword, NNS, NamedType, Canon);
  Types.push_back(T);
  ElaboratedTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}

QualType
ASTContext::getParenType(QualType InnerType) const {
  llvm::FoldingSetNodeID ID;
  ParenType::Profile(ID, InnerType);

  void *InsertPos = nullptr;
  ParenType *T = ParenTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);

  QualType Canon = InnerType;
  if (!Canon.isCanonical()) {
    Canon = getCanonicalType(InnerType);
    ParenType *CheckT = ParenTypes.FindNodeOrInsertPos(ID, InsertPos);
    assert(!CheckT && "Paren canonical type broken");
    (void)CheckT;
  }

  T = new (*this) ParenType(InnerType, Canon);
  Types.push_back(T);
  ParenTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}

QualType ASTContext::getDependentNameType(ElaboratedTypeKeyword Keyword,
                                          NestedNameSpecifier *NNS,
                                          const IdentifierInfo *Name,
                                          QualType Canon) const {
  if (Canon.isNull()) {
    NestedNameSpecifier *CanonNNS = getCanonicalNestedNameSpecifier(NNS);
    ElaboratedTypeKeyword CanonKeyword = Keyword;
    if (Keyword == ETK_None)
      CanonKeyword = ETK_Typename;

    if (CanonNNS != NNS || CanonKeyword != Keyword)
      Canon = getDependentNameType(CanonKeyword, CanonNNS, Name);
  }

  llvm::FoldingSetNodeID ID;
  DependentNameType::Profile(ID, Keyword, NNS, Name);

  void *InsertPos = nullptr;
  DependentNameType *T
    = DependentNameTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);

  T = new (*this) DependentNameType(Keyword, NNS, Name, Canon);
  Types.push_back(T);
  DependentNameTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}

QualType
ASTContext::getDependentTemplateSpecializationType(
                                 ElaboratedTypeKeyword Keyword,
                                 NestedNameSpecifier *NNS,
                                 const IdentifierInfo *Name,
                                 const TemplateArgumentListInfo &Args) const {
  // TODO: avoid this copy
  SmallVector<TemplateArgument, 16> ArgCopy;
  for (unsigned I = 0, E = Args.size(); I != E; ++I)
    ArgCopy.push_back(Args[I].getArgument());
  return getDependentTemplateSpecializationType(Keyword, NNS, Name,
                                                ArgCopy.size(),
                                                ArgCopy.data());
}

QualType
ASTContext::getDependentTemplateSpecializationType(
                                 ElaboratedTypeKeyword Keyword,
                                 NestedNameSpecifier *NNS,
                                 const IdentifierInfo *Name,
                                 unsigned NumArgs,
                                 const TemplateArgument *Args) const {
  assert((!NNS || NNS->isDependent()) &&
         "nested-name-specifier must be dependent");

  llvm::FoldingSetNodeID ID;
  DependentTemplateSpecializationType::Profile(ID, *this, Keyword, NNS,
                                               Name, NumArgs, Args);

  void *InsertPos = nullptr;
  DependentTemplateSpecializationType *T
    = DependentTemplateSpecializationTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);

  NestedNameSpecifier *CanonNNS = getCanonicalNestedNameSpecifier(NNS);

  ElaboratedTypeKeyword CanonKeyword = Keyword;
  if (Keyword == ETK_None) CanonKeyword = ETK_Typename;

  bool AnyNonCanonArgs = false;
  SmallVector<TemplateArgument, 16> CanonArgs(NumArgs);
  for (unsigned I = 0; I != NumArgs; ++I) {
    CanonArgs[I] = getCanonicalTemplateArgument(Args[I]);
    if (!CanonArgs[I].structurallyEquals(Args[I]))
      AnyNonCanonArgs = true;
  }

  QualType Canon;
  if (AnyNonCanonArgs || CanonNNS != NNS || CanonKeyword != Keyword) {
    Canon = getDependentTemplateSpecializationType(CanonKeyword, CanonNNS,
                                                   Name, NumArgs,
                                                   CanonArgs.data());

    // Find the insert position again.
    DependentTemplateSpecializationTypes.FindNodeOrInsertPos(ID, InsertPos);
  }

  void *Mem = Allocate((sizeof(DependentTemplateSpecializationType) +
                        sizeof(TemplateArgument) * NumArgs),
                       TypeAlignment);
  T = new (Mem) DependentTemplateSpecializationType(Keyword, NNS,
                                                    Name, NumArgs, Args, Canon);
  Types.push_back(T);
  DependentTemplateSpecializationTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}

QualType ASTContext::getPackExpansionType(QualType Pattern,
                                          Optional<unsigned> NumExpansions) {
  llvm::FoldingSetNodeID ID;
  PackExpansionType::Profile(ID, Pattern, NumExpansions);

  assert(Pattern->containsUnexpandedParameterPack() &&
         "Pack expansions must expand one or more parameter packs");
  void *InsertPos = nullptr;
  PackExpansionType *T
    = PackExpansionTypes.FindNodeOrInsertPos(ID, InsertPos);
  if (T)
    return QualType(T, 0);

  QualType Canon;
  if (!Pattern.isCanonical()) {
    Canon = getCanonicalType(Pattern);
    // The canonical type might not contain an unexpanded parameter pack, if it
    // contains an alias template specialization which ignores one of its
    // parameters.
    if (Canon->containsUnexpandedParameterPack()) {
      Canon = getPackExpansionType(Canon, NumExpansions);

      // Find the insert position again, in case we inserted an element into
      // PackExpansionTypes and invalidated our insert position.
      PackExpansionTypes.FindNodeOrInsertPos(ID, InsertPos);
    }
  }

  T = new (*this) PackExpansionType(Pattern, Canon, NumExpansions);
  Types.push_back(T);
  PackExpansionTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}

/// CmpProtocolNames - Comparison predicate for sorting protocols
/// alphabetically.
static bool CmpProtocolNames(const ObjCProtocolDecl *LHS,
                            const ObjCProtocolDecl *RHS) {
  return LHS->getDeclName() < RHS->getDeclName();
}

static bool areSortedAndUniqued(ObjCProtocolDecl * const *Protocols,
                                unsigned NumProtocols) {
  if (NumProtocols == 0) return true;

  if (Protocols[0]->getCanonicalDecl() != Protocols[0])
    return false;

  for (unsigned i = 1; i != NumProtocols; ++i)
    if (!CmpProtocolNames(Protocols[i-1], Protocols[i]) ||
        Protocols[i]->getCanonicalDecl() != Protocols[i])
      return false;
  return true;
}

static void SortAndUniqueProtocols(ObjCProtocolDecl **Protocols,
                                   unsigned &NumProtocols) {
  ObjCProtocolDecl **ProtocolsEnd = Protocols+NumProtocols;

  // Sort protocols, keyed by name.
  std::sort(Protocols, Protocols+NumProtocols, CmpProtocolNames);

  // Canonicalize.
  for (unsigned I = 0, N = NumProtocols; I != N; ++I)
    Protocols[I] = Protocols[I]->getCanonicalDecl();

  // Remove duplicates.
  ProtocolsEnd = std::unique(Protocols, ProtocolsEnd);
  NumProtocols = ProtocolsEnd-Protocols;
}

QualType ASTContext::getObjCObjectType(QualType BaseType,
                                       ObjCProtocolDecl * const *Protocols,
                                       unsigned NumProtocols) const {
  // If the base type is an interface and there aren't any protocols
  // to add, then the interface type will do just fine.
  if (!NumProtocols && isa<ObjCInterfaceType>(BaseType))
    return BaseType;

  // Look in the folding set for an existing type.
  llvm::FoldingSetNodeID ID;
  ObjCObjectTypeImpl::Profile(ID, BaseType, Protocols, NumProtocols);
  void *InsertPos = nullptr;
  if (ObjCObjectType *QT = ObjCObjectTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(QT, 0);

  // Build the canonical type, which has the canonical base type and
  // a sorted-and-uniqued list of protocols.
  QualType Canonical;
  bool ProtocolsSorted = areSortedAndUniqued(Protocols, NumProtocols);
  if (!ProtocolsSorted || !BaseType.isCanonical()) {
    if (!ProtocolsSorted) {
      SmallVector<ObjCProtocolDecl*, 8> Sorted(Protocols,
                                                     Protocols + NumProtocols);
      unsigned UniqueCount = NumProtocols;

      SortAndUniqueProtocols(&Sorted[0], UniqueCount);
      Canonical = getObjCObjectType(getCanonicalType(BaseType),
                                    &Sorted[0], UniqueCount);
    } else {
      Canonical = getObjCObjectType(getCanonicalType(BaseType),
                                    Protocols, NumProtocols);
    }

    // Regenerate InsertPos.
    ObjCObjectTypes.FindNodeOrInsertPos(ID, InsertPos);
  }

  unsigned Size = sizeof(ObjCObjectTypeImpl);
  Size += NumProtocols * sizeof(ObjCProtocolDecl *);
  void *Mem = Allocate(Size, TypeAlignment);
  ObjCObjectTypeImpl *T =
    new (Mem) ObjCObjectTypeImpl(Canonical, BaseType, Protocols, NumProtocols);

  Types.push_back(T);
  ObjCObjectTypes.InsertNode(T, InsertPos);
  return QualType(T, 0);
}

/// ObjCObjectAdoptsQTypeProtocols - Checks that protocols in IC's
/// protocol list adopt all protocols in QT's qualified-id protocol
/// list.
bool ASTContext::ObjCObjectAdoptsQTypeProtocols(QualType QT,
                                                ObjCInterfaceDecl *IC) {
  if (!QT->isObjCQualifiedIdType())
    return false;

  if (const ObjCObjectPointerType *OPT = QT->getAs<ObjCObjectPointerType>()) {
    // If both the right and left sides have qualifiers.
    for (auto *Proto : OPT->quals()) {
      if (!IC->ClassImplementsProtocol(Proto, false))
        return false;
    }
    return true;
  }
  return false;
}

/// QIdProtocolsAdoptObjCObjectProtocols - Checks that protocols in
/// QT's qualified-id protocol list adopt all protocols in IDecl's list
/// of protocols.
bool ASTContext::QIdProtocolsAdoptObjCObjectProtocols(QualType QT,
                                                ObjCInterfaceDecl *IDecl) {
  if (!QT->isObjCQualifiedIdType())
    return false;
  const ObjCObjectPointerType *OPT = QT->getAs<ObjCObjectPointerType>();
  if (!OPT)
    return false;
  if (!IDecl->hasDefinition())
    return false;
  llvm::SmallPtrSet<ObjCProtocolDecl *, 8> InheritedProtocols;
  CollectInheritedProtocols(IDecl, InheritedProtocols);
  if (InheritedProtocols.empty())
    return false;
  // Check that if every protocol in list of id<plist> conforms to a protcol
  // of IDecl's, then bridge casting is ok.
  bool Conforms = false;
  for (auto *Proto : OPT->quals()) {
    Conforms = false;
    for (auto *PI : InheritedProtocols) {
      if (ProtocolCompatibleWithProtocol(Proto, PI)) {
        Conforms = true;
        break;
      }
    }
    if (!Conforms)
      break;
  }
  if (Conforms)
    return true;

  for (auto *PI : InheritedProtocols) {
    // If both the right and left sides have qualifiers.
    bool Adopts = false;
    for (auto *Proto : OPT->quals()) {
      // return 'true' if 'PI' is in the inheritance hierarchy of Proto
      if ((Adopts = ProtocolCompatibleWithProtocol(PI, Proto)))
        break;
    }
    if (!Adopts)
      return false;
  }
  return true;
}

/// getObjCObjectPointerType - Return a ObjCObjectPointerType type for
/// the given object type.
QualType ASTContext::getObjCObjectPointerType(QualType ObjectT) const {
  llvm::FoldingSetNodeID ID;
  ObjCObjectPointerType::Profile(ID, ObjectT);

  void *InsertPos = nullptr;
  if (ObjCObjectPointerType *QT =
              ObjCObjectPointerTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(QT, 0);

  // Find the canonical object type.
  QualType Canonical;
  if (!ObjectT.isCanonical()) {
    Canonical = getObjCObjectPointerType(getCanonicalType(ObjectT));

    // Regenerate InsertPos.
    ObjCObjectPointerTypes.FindNodeOrInsertPos(ID, InsertPos);
  }

  // No match.
  void *Mem = Allocate(sizeof(ObjCObjectPointerType), TypeAlignment);
  ObjCObjectPointerType *QType =
    new (Mem) ObjCObjectPointerType(Canonical, ObjectT);

  Types.push_back(QType);
  ObjCObjectPointerTypes.InsertNode(QType, InsertPos);
  return QualType(QType, 0);
}

/// getObjCInterfaceType - Return the unique reference to the type for the
/// specified ObjC interface decl. The list of protocols is optional.
QualType ASTContext::getObjCInterfaceType(const ObjCInterfaceDecl *Decl,
                                          ObjCInterfaceDecl *PrevDecl) const {
  if (Decl->TypeForDecl)
    return QualType(Decl->TypeForDecl, 0);

  if (PrevDecl) {
    assert(PrevDecl->TypeForDecl && "previous decl has no TypeForDecl");
    Decl->TypeForDecl = PrevDecl->TypeForDecl;
    return QualType(PrevDecl->TypeForDecl, 0);
  }

  // Prefer the definition, if there is one.
  if (const ObjCInterfaceDecl *Def = Decl->getDefinition())
    Decl = Def;

  void *Mem = Allocate(sizeof(ObjCInterfaceType), TypeAlignment);
  ObjCInterfaceType *T = new (Mem) ObjCInterfaceType(Decl);
  Decl->TypeForDecl = T;
  Types.push_back(T);
  return QualType(T, 0);
}

/// getTypeOfExprType - Unlike many "get<Type>" functions, we can't unique
/// TypeOfExprType AST's (since expression's are never shared). For example,
/// multiple declarations that refer to "typeof(x)" all contain different
/// DeclRefExpr's. This doesn't effect the type checker, since it operates
/// on canonical type's (which are always unique).
QualType ASTContext::getTypeOfExprType(Expr *tofExpr) const {
  TypeOfExprType *toe;
  if (tofExpr->isTypeDependent()) {
    llvm::FoldingSetNodeID ID;
    DependentTypeOfExprType::Profile(ID, *this, tofExpr);

    void *InsertPos = nullptr;
    DependentTypeOfExprType *Canon
      = DependentTypeOfExprTypes.FindNodeOrInsertPos(ID, InsertPos);
    if (Canon) {
      // We already have a "canonical" version of an identical, dependent
      // typeof(expr) type. Use that as our canonical type.
      toe = new (*this, TypeAlignment) TypeOfExprType(tofExpr,
                                          QualType((TypeOfExprType*)Canon, 0));
    } else {
      // Build a new, canonical typeof(expr) type.
      Canon
        = new (*this, TypeAlignment) DependentTypeOfExprType(*this, tofExpr);
      DependentTypeOfExprTypes.InsertNode(Canon, InsertPos);
      toe = Canon;
    }
  } else {
    QualType Canonical = getCanonicalType(tofExpr->getType());
    toe = new (*this, TypeAlignment) TypeOfExprType(tofExpr, Canonical);
  }
  Types.push_back(toe);
  return QualType(toe, 0);
}

/// getTypeOfType -  Unlike many "get<Type>" functions, we don't unique
/// TypeOfType nodes. The only motivation to unique these nodes would be
/// memory savings. Since typeof(t) is fairly uncommon, space shouldn't be
/// an issue. This doesn't affect the type checker, since it operates
/// on canonical types (which are always unique).
QualType ASTContext::getTypeOfType(QualType tofType) const {
  QualType Canonical = getCanonicalType(tofType);
  TypeOfType *tot = new (*this, TypeAlignment) TypeOfType(tofType, Canonical);
  Types.push_back(tot);
  return QualType(tot, 0);
}


/// \brief Unlike many "get<Type>" functions, we don't unique DecltypeType
/// nodes. This would never be helpful, since each such type has its own
/// expression, and would not give a significant memory saving, since there
/// is an Expr tree under each such type.
QualType ASTContext::getDecltypeType(Expr *e, QualType UnderlyingType) const {
  DecltypeType *dt;

  // C++11 [temp.type]p2:
  //   If an expression e involves a template parameter, decltype(e) denotes a
  //   unique dependent type. Two such decltype-specifiers refer to the same
  //   type only if their expressions are equivalent (14.5.6.1).
  if (e->isInstantiationDependent()) {
    llvm::FoldingSetNodeID ID;
    DependentDecltypeType::Profile(ID, *this, e);

    void *InsertPos = nullptr;
    DependentDecltypeType *Canon
      = DependentDecltypeTypes.FindNodeOrInsertPos(ID, InsertPos);
    if (!Canon) {
      // Build a new, canonical typeof(expr) type.
      Canon = new (*this, TypeAlignment) DependentDecltypeType(*this, e);
      DependentDecltypeTypes.InsertNode(Canon, InsertPos);
    }
    dt = new (*this, TypeAlignment)
        DecltypeType(e, UnderlyingType, QualType((DecltypeType *)Canon, 0));
  } else {
    dt = new (*this, TypeAlignment)
        DecltypeType(e, UnderlyingType, getCanonicalType(UnderlyingType));
  }
  Types.push_back(dt);
  return QualType(dt, 0);
}

/// getUnaryTransformationType - We don't unique these, since the memory
/// savings are minimal and these are rare.
QualType ASTContext::getUnaryTransformType(QualType BaseType,
                                           QualType UnderlyingType,
                                           UnaryTransformType::UTTKind Kind)
    const {
  UnaryTransformType *Ty =
    new (*this, TypeAlignment) UnaryTransformType (BaseType, UnderlyingType,
                                                   Kind,
                                 UnderlyingType->isDependentType() ?
                                 QualType() : getCanonicalType(UnderlyingType));
  Types.push_back(Ty);
  return QualType(Ty, 0);
}

/// getAutoType - Return the uniqued reference to the 'auto' type which has been
/// deduced to the given type, or to the canonical undeduced 'auto' type, or the
/// canonical deduced-but-dependent 'auto' type.
QualType ASTContext::getAutoType(QualType DeducedType, bool IsDecltypeAuto,
                                 bool IsDependent) const {
  if (DeducedType.isNull() && !IsDecltypeAuto && !IsDependent)
    return getAutoDeductType();

  // Look in the folding set for an existing type.
  void *InsertPos = nullptr;
  llvm::FoldingSetNodeID ID;
  AutoType::Profile(ID, DeducedType, IsDecltypeAuto, IsDependent);
  if (AutoType *AT = AutoTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(AT, 0);

  AutoType *AT = new (*this, TypeAlignment) AutoType(DeducedType,
                                                     IsDecltypeAuto,
                                                     IsDependent);
  Types.push_back(AT);
  if (InsertPos)
    AutoTypes.InsertNode(AT, InsertPos);
  return QualType(AT, 0);
}

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

  void *InsertPos = nullptr;
  if (AtomicType *AT = AtomicTypes.FindNodeOrInsertPos(ID, InsertPos))
    return QualType(AT, 0);

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

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

/// getAutoDeductType - Get type pattern for deducing against 'auto'.
QualType ASTContext::getAutoDeductType() const {
  if (AutoDeductTy.isNull())
    AutoDeductTy = QualType(
      new (*this, TypeAlignment) AutoType(QualType(), /*decltype(auto)*/false,
                                          /*dependent*/false),
      0);
  return AutoDeductTy;
}

/// getAutoRRefDeductType - Get type pattern for deducing against 'auto &&'.
QualType ASTContext::getAutoRRefDeductType() const {
  if (AutoRRefDeductTy.isNull())
    AutoRRefDeductTy = getRValueReferenceType(getAutoDeductType());
  assert(!AutoRRefDeductTy.isNull() && "can't build 'auto &&' pattern");
  return AutoRRefDeductTy;
}

/// getTagDeclType - Return the unique reference to the type for the
/// specified TagDecl (struct/union/class/enum) decl.
QualType ASTContext::getTagDeclType(const TagDecl *Decl) const {
  assert (Decl);
  // FIXME: What is the design on getTagDeclType when it requires casting
  // away const?  mutable?
  return getTypeDeclType(const_cast<TagDecl*>(Decl));
}

/// getSizeType - Return the unique type for "size_t" (C99 7.17), the result
/// of the sizeof operator (C99 6.5.3.4p4). The value is target dependent and
/// needs to agree with the definition in <stddef.h>.
CanQualType ASTContext::getSizeType() const {
  return getFromTargetType(Target->getSizeType());
}

/// getIntMaxType - Return the unique type for "intmax_t" (C99 7.18.1.5).
CanQualType ASTContext::getIntMaxType() const {
  return getFromTargetType(Target->getIntMaxType());
}

/// getUIntMaxType - Return the unique type for "uintmax_t" (C99 7.18.1.5).
CanQualType ASTContext::getUIntMaxType() const {
  return getFromTargetType(Target->getUIntMaxType());
}

/// getSignedWCharType - Return the type of "signed wchar_t".
/// Used when in C++, as a GCC extension.
QualType ASTContext::getSignedWCharType() const {
  // FIXME: derive from "Target" ?
  return WCharTy;
}

/// getUnsignedWCharType - Return the type of "unsigned wchar_t".
/// Used when in C++, as a GCC extension.
QualType ASTContext::getUnsignedWCharType() const {
  // FIXME: derive from "Target" ?
  return UnsignedIntTy;
}

QualType ASTContext::getIntPtrType() const {
  return getFromTargetType(Target->getIntPtrType());
}

QualType ASTContext::getUIntPtrType() const {
  return getCorrespondingUnsignedType(getIntPtrType());
}

/// getPointerDiffType - Return the unique type for "ptrdiff_t" (C99 7.17)
/// defined in <stddef.h>. Pointer - pointer requires this (C99 6.5.6p9).
QualType ASTContext::getPointerDiffType() const {
  return getFromTargetType(Target->getPtrDiffType(0));
}

/// \brief Return the unique type for "pid_t" defined in
/// <sys/types.h>. We need this to compute the correct type for vfork().
QualType ASTContext::getProcessIDType() const {
  return getFromTargetType(Target->getProcessIDType());
}

//===----------------------------------------------------------------------===//
//                              Type Operators
//===----------------------------------------------------------------------===//

CanQualType ASTContext::getCanonicalParamType(QualType T) const {
  // Push qualifiers into arrays, and then discard any remaining
  // qualifiers.
  T = getCanonicalType(T);
  T = getVariableArrayDecayedType(T);
  const Type *Ty = T.getTypePtr();
  QualType Result;
  if (isa<ArrayType>(Ty)) {
    Result = getArrayDecayedType(QualType(Ty,0));
  } else if (isa<FunctionType>(Ty)) {
    Result = getPointerType(QualType(Ty, 0));
  } else {
    Result = QualType(Ty, 0);
  }

  return CanQualType::CreateUnsafe(Result);
}

QualType ASTContext::getUnqualifiedArrayType(QualType type,
                                             Qualifiers &quals) {
  SplitQualType splitType = type.getSplitUnqualifiedType();

  // FIXME: getSplitUnqualifiedType() actually walks all the way to
  // the unqualified desugared type and then drops it on the floor.
  // We then have to strip that sugar back off with
  // getUnqualifiedDesugaredType(), which is silly.
  const ArrayType *AT =
    dyn_cast<ArrayType>(splitType.Ty->getUnqualifiedDesugaredType());

  // If we don't have an array, just use the results in splitType.
  if (!AT) {
    quals = splitType.Quals;
    return QualType(splitType.Ty, 0);
  }

  // Otherwise, recurse on the array's element type.
  QualType elementType = AT->getElementType();
  QualType unqualElementType = getUnqualifiedArrayType(elementType, quals);

  // If that didn't change the element type, AT has no qualifiers, so we
  // can just use the results in splitType.
  if (elementType == unqualElementType) {
    assert(quals.empty()); // from the recursive call
    quals = splitType.Quals;
    return QualType(splitType.Ty, 0);
  }

  // Otherwise, add in the qualifiers from the outermost type, then
  // build the type back up.
  quals.addConsistentQualifiers(splitType.Quals);

  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT)) {
    return getConstantArrayType(unqualElementType, CAT->getSize(),
                                CAT->getSizeModifier(), 0);
  }

  if (const IncompleteArrayType *IAT = dyn_cast<IncompleteArrayType>(AT)) {
    return getIncompleteArrayType(unqualElementType, IAT->getSizeModifier(), 0);
  }

  if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(AT)) {
    return getVariableArrayType(unqualElementType,
                                VAT->getSizeExpr(),
                                VAT->getSizeModifier(),
                                VAT->getIndexTypeCVRQualifiers(),
                                VAT->getBracketsRange());
  }

  const DependentSizedArrayType *DSAT = cast<DependentSizedArrayType>(AT);
  return getDependentSizedArrayType(unqualElementType, DSAT->getSizeExpr(),
                                    DSAT->getSizeModifier(), 0,
                                    SourceRange());
}

/// UnwrapSimilarPointerTypes - If T1 and T2 are pointer types  that
/// may be similar (C++ 4.4), replaces T1 and T2 with the type that
/// they point to and return true. If T1 and T2 aren't pointer types
/// or pointer-to-member types, or if they are not similar at this
/// level, returns false and leaves T1 and T2 unchanged. Top-level
/// qualifiers on T1 and T2 are ignored. This function will typically
/// be called in a loop that successively "unwraps" pointer and
/// pointer-to-member types to compare them at each level.
bool ASTContext::UnwrapSimilarPointerTypes(QualType &T1, QualType &T2) {
  const PointerType *T1PtrType = T1->getAs<PointerType>(),
                    *T2PtrType = T2->getAs<PointerType>();
  if (T1PtrType && T2PtrType) {
    T1 = T1PtrType->getPointeeType();
    T2 = T2PtrType->getPointeeType();
    return true;
  }

  const MemberPointerType *T1MPType = T1->getAs<MemberPointerType>(),
                          *T2MPType = T2->getAs<MemberPointerType>();
  if (T1MPType && T2MPType &&
      hasSameUnqualifiedType(QualType(T1MPType->getClass(), 0),
                             QualType(T2MPType->getClass(), 0))) {
    T1 = T1MPType->getPointeeType();
    T2 = T2MPType->getPointeeType();
    return true;
  }

  if (getLangOpts().ObjC1) {
    const ObjCObjectPointerType *T1OPType = T1->getAs<ObjCObjectPointerType>(),
                                *T2OPType = T2->getAs<ObjCObjectPointerType>();
    if (T1OPType && T2OPType) {
      T1 = T1OPType->getPointeeType();
      T2 = T2OPType->getPointeeType();
      return true;
    }
  }

  // FIXME: Block pointers, too?

  return false;
}

DeclarationNameInfo
ASTContext::getNameForTemplate(TemplateName Name,
                               SourceLocation NameLoc) const {
  switch (Name.getKind()) {
  case TemplateName::QualifiedTemplate:
  case TemplateName::Template:
    // DNInfo work in progress: CHECKME: what about DNLoc?
    return DeclarationNameInfo(Name.getAsTemplateDecl()->getDeclName(),
                               NameLoc);

  case TemplateName::OverloadedTemplate: {
    OverloadedTemplateStorage *Storage = Name.getAsOverloadedTemplate();
    // DNInfo work in progress: CHECKME: what about DNLoc?
    return DeclarationNameInfo((*Storage->begin())->getDeclName(), NameLoc);
  }

  case TemplateName::DependentTemplate: {
    DependentTemplateName *DTN = Name.getAsDependentTemplateName();
    DeclarationName DName;
    if (DTN->isIdentifier()) {
      DName = DeclarationNames.getIdentifier(DTN->getIdentifier());
      return DeclarationNameInfo(DName, NameLoc);
    } else {
      DName = DeclarationNames.getCXXOperatorName(DTN->getOperator());
      // DNInfo work in progress: FIXME: source locations?
      DeclarationNameLoc DNLoc;
      DNLoc.CXXOperatorName.BeginOpNameLoc = SourceLocation().getRawEncoding();
      DNLoc.CXXOperatorName.EndOpNameLoc = SourceLocation().getRawEncoding();
      return DeclarationNameInfo(DName, NameLoc, DNLoc);
    }
  }

  case TemplateName::SubstTemplateTemplateParm: {
    SubstTemplateTemplateParmStorage *subst
      = Name.getAsSubstTemplateTemplateParm();
    return DeclarationNameInfo(subst->getParameter()->getDeclName(),
                               NameLoc);
  }

  case TemplateName::SubstTemplateTemplateParmPack: {
    SubstTemplateTemplateParmPackStorage *subst
      = Name.getAsSubstTemplateTemplateParmPack();
    return DeclarationNameInfo(subst->getParameterPack()->getDeclName(),
                               NameLoc);
  }
  }

  llvm_unreachable("bad template name kind!");
}

TemplateName ASTContext::getCanonicalTemplateName(TemplateName Name) const {
  switch (Name.getKind()) {
  case TemplateName::QualifiedTemplate:
  case TemplateName::Template: {
    TemplateDecl *Template = Name.getAsTemplateDecl();
    if (TemplateTemplateParmDecl *TTP
          = dyn_cast<TemplateTemplateParmDecl>(Template))
      Template = getCanonicalTemplateTemplateParmDecl(TTP);

    // The canonical template name is the canonical template declaration.
    return TemplateName(cast<TemplateDecl>(Template->getCanonicalDecl()));
  }

  case TemplateName::OverloadedTemplate:
    llvm_unreachable("cannot canonicalize overloaded template");

  case TemplateName::DependentTemplate: {
    DependentTemplateName *DTN = Name.getAsDependentTemplateName();
    assert(DTN && "Non-dependent template names must refer to template decls.");
    return DTN->CanonicalTemplateName;
  }

  case TemplateName::SubstTemplateTemplateParm: {
    SubstTemplateTemplateParmStorage *subst
      = Name.getAsSubstTemplateTemplateParm();
    return getCanonicalTemplateName(subst->getReplacement());
  }

  case TemplateName::SubstTemplateTemplateParmPack: {
    SubstTemplateTemplateParmPackStorage *subst
                                  = Name.getAsSubstTemplateTemplateParmPack();
    TemplateTemplateParmDecl *canonParameter
      = getCanonicalTemplateTemplateParmDecl(subst->getParameterPack());
    TemplateArgument canonArgPack
      = getCanonicalTemplateArgument(subst->getArgumentPack());
    return getSubstTemplateTemplateParmPack(canonParameter, canonArgPack);
  }
  }

  llvm_unreachable("bad template name!");
}

bool ASTContext::hasSameTemplateName(TemplateName X, TemplateName Y) {
  X = getCanonicalTemplateName(X);
  Y = getCanonicalTemplateName(Y);
  return X.getAsVoidPointer() == Y.getAsVoidPointer();
}

TemplateArgument
ASTContext::getCanonicalTemplateArgument(const TemplateArgument &Arg) const {
  switch (Arg.getKind()) {
    case TemplateArgument::Null:
      return Arg;

    case TemplateArgument::Expression:
      return Arg;

    case TemplateArgument::Declaration: {
      ValueDecl *D = cast<ValueDecl>(Arg.getAsDecl()->getCanonicalDecl());
      return TemplateArgument(D, Arg.isDeclForReferenceParam());
    }

    case TemplateArgument::NullPtr:
      return TemplateArgument(getCanonicalType(Arg.getNullPtrType()),
                              /*isNullPtr*/true);

    case TemplateArgument::Template:
      return TemplateArgument(getCanonicalTemplateName(Arg.getAsTemplate()));

    case TemplateArgument::TemplateExpansion:
      return TemplateArgument(getCanonicalTemplateName(
                                         Arg.getAsTemplateOrTemplatePattern()),
                              Arg.getNumTemplateExpansions());

    case TemplateArgument::Integral:
      return TemplateArgument(Arg, getCanonicalType(Arg.getIntegralType()));

    case TemplateArgument::Type:
      return TemplateArgument(getCanonicalType(Arg.getAsType()));

    case TemplateArgument::Pack: {
      if (Arg.pack_size() == 0)
        return Arg;

      TemplateArgument *CanonArgs
        = new (*this) TemplateArgument[Arg.pack_size()];
      unsigned Idx = 0;
      for (TemplateArgument::pack_iterator A = Arg.pack_begin(),
                                        AEnd = Arg.pack_end();
           A != AEnd; (void)++A, ++Idx)
        CanonArgs[Idx] = getCanonicalTemplateArgument(*A);

      return TemplateArgument(CanonArgs, Arg.pack_size());
    }
  }

  // Silence GCC warning
  llvm_unreachable("Unhandled template argument kind");
}

NestedNameSpecifier *
ASTContext::getCanonicalNestedNameSpecifier(NestedNameSpecifier *NNS) const {
  if (!NNS)
    return nullptr;

  switch (NNS->getKind()) {
  case NestedNameSpecifier::Identifier:
    // Canonicalize the prefix but keep the identifier the same.
    return NestedNameSpecifier::Create(*this,
                         getCanonicalNestedNameSpecifier(NNS->getPrefix()),
                                       NNS->getAsIdentifier());

  case NestedNameSpecifier::Namespace:
    // A namespace is canonical; build a nested-name-specifier with
    // this namespace and no prefix.
    return NestedNameSpecifier::Create(*this, nullptr,
                                 NNS->getAsNamespace()->getOriginalNamespace());

  case NestedNameSpecifier::NamespaceAlias:
    // A namespace is canonical; build a nested-name-specifier with
    // this namespace and no prefix.
    return NestedNameSpecifier::Create(*this, nullptr,
                                    NNS->getAsNamespaceAlias()->getNamespace()
                                                      ->getOriginalNamespace());

  case NestedNameSpecifier::TypeSpec:
  case NestedNameSpecifier::TypeSpecWithTemplate: {
    QualType T = getCanonicalType(QualType(NNS->getAsType(), 0));

    // If we have some kind of dependent-named type (e.g., "typename T::type"),
    // break it apart into its prefix and identifier, then reconsititute those
    // as the canonical nested-name-specifier. This is required to canonical