text: //===--- DeclBase.cpp - Declaration AST Node Implementation ---------------===//
  //
  //                     The LLVM37 Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file implements the Decl and DeclContext classes.
  //
  //===----------------------------------------------------------------------===//
  
  #include "clang/AST/DeclBase.h"
  #include "clang/AST/ASTContext.h"
  #include "clang/AST/ASTMutationListener.h"
  #include "clang/AST/Attr.h"
  #include "clang/AST/Decl.h"
  #include "clang/AST/DeclCXX.h"
  #include "clang/AST/DeclContextInternals.h"
  #include "clang/AST/DeclFriend.h"
  #include "clang/AST/DeclObjC.h"
  #include "clang/AST/DeclOpenMP.h"
  #include "clang/AST/DeclTemplate.h"
  #include "clang/AST/DependentDiagnostic.h"
  #include "clang/AST/ExternalASTSource.h"
  #include "clang/AST/Stmt.h"
  #include "clang/AST/StmtCXX.h"
  #include "clang/AST/Type.h"
  #include "clang/Basic/TargetInfo.h"
  #include "llvm37/ADT/DenseMap.h"
  #include "llvm37/Support/raw_ostream.h"
  #include <algorithm>
  
  #include "llvm37/Support/OacrIgnoreCond.h" // HLSL Change - options change visibility rules
  
  using namespace clang;
  
  //===----------------------------------------------------------------------===//
  //  Statistics
  //===----------------------------------------------------------------------===//
  
  #define DECL(DERIVED, BASE) static int n##DERIVED##s = 0;
  #define ABSTRACT_DECL(DECL)
  #include "clang/AST/DeclNodes.inc"
  
  void Decl::updateOutOfDate(IdentifierInfo &II) const {
    getASTContext().getExternalSource()->updateOutOfDateIdentifier(II);
  }
  
  void *Decl::operator new(std::size_t Size, const ASTContext &Context,
                           unsigned ID, std::size_t Extra) {
    // Allocate an extra 8 bytes worth of storage, which ensures that the
    // resulting pointer will still be 8-byte aligned. 
    void *Start = Context.Allocate(Size + Extra + 8);
    void *Result = (char*)Start + 8;
  
    unsigned *PrefixPtr = (unsigned *)Result - 2;
  
    // Zero out the first 4 bytes; this is used to store the owning module ID.
    PrefixPtr[0] = 0;
  
    // Store the global declaration ID in the second 4 bytes.
    PrefixPtr[1] = ID;
  
    return Result;
  }
  
  void *Decl::operator new(std::size_t Size, const ASTContext &Ctx,
                           DeclContext *Parent, std::size_t Extra) {
    assert(!Parent || &Parent->getParentASTContext() == &Ctx);
    // With local visibility enabled, we track the owning module even for local
    // declarations.
    if (Ctx.getLangOpts().ModulesLocalVisibility) {
      void *Buffer = ::operator new(sizeof(Module *) + Size + Extra, Ctx);
      return new (Buffer) Module*(nullptr) + 1;
    }
    return ::operator new(Size + Extra, Ctx);
  }
  
  Module *Decl::getOwningModuleSlow() const {
    assert(isFromASTFile() && "Not from AST file?");
    return getASTContext().getExternalSource()->getModule(getOwningModuleID());
  }
  
  bool Decl::hasLocalOwningModuleStorage() const {
    return getASTContext().getLangOpts().ModulesLocalVisibility;
  }
  
  const char *Decl::getDeclKindName() const {
    switch (DeclKind) {
    default: llvm37_unreachable("Declaration not in DeclNodes.inc!");
  #define DECL(DERIVED, BASE) case DERIVED: return #DERIVED;
  #define ABSTRACT_DECL(DECL)
  #include "clang/AST/DeclNodes.inc"
    }
  }
  
  void Decl::setInvalidDecl(bool Invalid) {
    InvalidDecl = Invalid;
    assert(!isa<TagDecl>(this) || !cast<TagDecl>(this)->isCompleteDefinition());
    if (Invalid && !isa<ParmVarDecl>(this)) {
      // Defensive maneuver for ill-formed code: we're likely not to make it to
      // a point where we set the access specifier, so default it to "public"
      // to avoid triggering asserts elsewhere in the front end. 
      setAccess(AS_public);
    }
  }
  
  const char *DeclContext::getDeclKindName() const {
    switch (DeclKind) {
    default: llvm37_unreachable("Declaration context not in DeclNodes.inc!");
  #define DECL(DERIVED, BASE) case Decl::DERIVED: return #DERIVED;
  #define ABSTRACT_DECL(DECL)
  #include "clang/AST/DeclNodes.inc"
    }
  }
  
  bool Decl::StatisticsEnabled = false;
  void Decl::EnableStatistics() {
    StatisticsEnabled = true;
  }
  
  void Decl::PrintStats() {
    llvm37::errs() << "\n*** Decl Stats:\n";
  
    int totalDecls = 0;
  #define DECL(DERIVED, BASE) totalDecls += n##DERIVED##s;
  #define ABSTRACT_DECL(DECL)
  #include "clang/AST/DeclNodes.inc"
    llvm37::errs() << "  " << totalDecls << " decls total.\n";
  
    int totalBytes = 0;
  #define DECL(DERIVED, BASE)                                             \
    if (n##DERIVED##s > 0) {                                              \
      totalBytes += (int)(n##DERIVED##s * sizeof(DERIVED##Decl));         \
      llvm37::errs() << "    " << n##DERIVED##s << " " #DERIVED " decls, "  \
                   << sizeof(DERIVED##Decl) << " each ("                  \
                   << n##DERIVED##s * sizeof(DERIVED##Decl)               \
                   << " bytes)\n";                                        \
    }
  #define ABSTRACT_DECL(DECL)
  #include "clang/AST/DeclNodes.inc"
  
    llvm37::errs() << "Total bytes = " << totalBytes << "\n";
  }
  
  void Decl::add(Kind k) {
    switch (k) {
  #define DECL(DERIVED, BASE) case DERIVED: ++n##DERIVED##s; break;
  #define ABSTRACT_DECL(DECL)
  #include "clang/AST/DeclNodes.inc"
    }
  }
  
  bool Decl::isTemplateParameterPack() const {
    if (const TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(this))
      return TTP->isParameterPack();
    if (const NonTypeTemplateParmDecl *NTTP
                                  = dyn_cast<NonTypeTemplateParmDecl>(this))
      return NTTP->isParameterPack();
    if (const TemplateTemplateParmDecl *TTP
                                      = dyn_cast<TemplateTemplateParmDecl>(this))
      return TTP->isParameterPack();
    return false;
  }
  
  bool Decl::isParameterPack() const {
    if (const ParmVarDecl *Parm = dyn_cast<ParmVarDecl>(this))
      return Parm->isParameterPack();
    
    return isTemplateParameterPack();
  }
  
  FunctionDecl *Decl::getAsFunction() {
    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(this))
      return FD;
    if (const FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(this))
      return FTD->getTemplatedDecl();
    return nullptr;
  }
  
  bool Decl::isTemplateDecl() const {
    return isa<TemplateDecl>(this);
  }
  
  const DeclContext *Decl::getParentFunctionOrMethod() const {
    for (const DeclContext *DC = getDeclContext();
         DC && !DC->isTranslationUnit() && !DC->isNamespace(); 
         DC = DC->getParent())
      if (DC->isFunctionOrMethod())
        return DC;
  
    return nullptr;
  }
  
  
  //===----------------------------------------------------------------------===//
  // PrettyStackTraceDecl Implementation
  //===----------------------------------------------------------------------===//
  
  void PrettyStackTraceDecl::print(raw_ostream &OS) const {
    SourceLocation TheLoc = Loc;
    if (TheLoc.isInvalid() && TheDecl)
      TheLoc = TheDecl->getLocation();
  
    if (TheLoc.isValid()) {
      TheLoc.print(OS, SM);
      OS << ": ";
    }
  
    OS << Message;
  
    if (const NamedDecl *DN = dyn_cast_or_null<NamedDecl>(TheDecl)) {
      OS << " '";
      DN->printQualifiedName(OS);
      OS << '\'';
    }
    OS << '\n';
  }
  
  //===----------------------------------------------------------------------===//
  // Decl Implementation
  //===----------------------------------------------------------------------===//
  
  // Out-of-line virtual method providing a home for Decl.
  Decl::~Decl() { }
  
  void Decl::setDeclContext(DeclContext *DC) {
    DeclCtx = DC;
  }
  
  void Decl::setLexicalDeclContext(DeclContext *DC) {
    if (DC == getLexicalDeclContext())
      return;
  
    if (isInSemaDC()) {
      setDeclContextsImpl(getDeclContext(), DC, getASTContext());
    } else {
      getMultipleDC()->LexicalDC = DC;
    }
    Hidden = cast<Decl>(DC)->Hidden;
  }
  
  void Decl::setDeclContextsImpl(DeclContext *SemaDC, DeclContext *LexicalDC,
                                 ASTContext &Ctx) {
    if (SemaDC == LexicalDC) {
      DeclCtx = SemaDC;
    } else {
      Decl::MultipleDC *MDC = new (Ctx) Decl::MultipleDC();
      MDC->SemanticDC = SemaDC;
      MDC->LexicalDC = LexicalDC;
      DeclCtx = MDC;
    }
  }
  
  bool Decl::isInAnonymousNamespace() const {
    const DeclContext *DC = getDeclContext();
    do {
      if (const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(DC))
        if (ND->isAnonymousNamespace())
          return true;
    } while ((DC = DC->getParent()));
  
    return false;
  }
  
  bool Decl::isInStdNamespace() const {
    return getDeclContext()->isStdNamespace();
  }
  
  TranslationUnitDecl *Decl::getTranslationUnitDecl() {
    if (TranslationUnitDecl *TUD = dyn_cast<TranslationUnitDecl>(this))
      return TUD;
  
    DeclContext *DC = getDeclContext();
    assert(DC && "This decl is not contained in a translation unit!");
  
    while (!DC->isTranslationUnit()) {
      DC = DC->getParent();
      assert(DC && "This decl is not contained in a translation unit!");
    }
  
    return cast<TranslationUnitDecl>(DC);
  }
  
  ASTContext &Decl::getASTContext() const {
    return getTranslationUnitDecl()->getASTContext();
  }
  
  ASTMutationListener *Decl::getASTMutationListener() const {
    return getASTContext().getASTMutationListener();
  }
  
  unsigned Decl::getMaxAlignment() const {
    if (!hasAttrs())
      return 0;
  
    unsigned Align = 0;
    const AttrVec &V = getAttrs();
    ASTContext &Ctx = getASTContext();
    specific_attr_iterator<AlignedAttr> I(V.begin()), E(V.end());
    for (; I != E; ++I)
      Align = std::max(Align, I->getAlignment(Ctx));
    return Align;
  }
  
  bool Decl::isUsed(bool CheckUsedAttr) const { 
    if (Used)
      return true;
    
    // Check for used attribute.
    if (CheckUsedAttr && hasAttr<UsedAttr>())
      return true;
  
    return false; 
  }
  
  void Decl::markUsed(ASTContext &C) {
    if (Used)
      return;
  
    if (C.getASTMutationListener())
      C.getASTMutationListener()->DeclarationMarkedUsed(this);
  
    Used = true;
  }
  
  bool Decl::isReferenced() const { 
    if (Referenced)
      return true;
  
    // Check redeclarations.
    for (auto I : redecls())
      if (I->Referenced)
        return true;
  
    return false; 
  }
  
  /// \brief Determine the availability of the given declaration based on
  /// the target platform.
  ///
  /// When it returns an availability result other than \c AR_Available,
  /// if the \p Message parameter is non-NULL, it will be set to a
  /// string describing why the entity is unavailable.
  ///
  /// FIXME: Make these strings localizable, since they end up in
  /// diagnostics.
  static AvailabilityResult CheckAvailability(ASTContext &Context,
                                              const AvailabilityAttr *A,
                                              std::string *Message) {
    VersionTuple TargetMinVersion =
      Context.getTargetInfo().getPlatformMinVersion();
  
    if (TargetMinVersion.empty())
      return AR_Available;
  
    // Check if this is an App Extension "platform", and if so chop off
    // the suffix for matching with the actual platform.
    StringRef ActualPlatform = A->getPlatform()->getName();
    StringRef RealizedPlatform = ActualPlatform;
    if (Context.getLangOpts().AppExt) {
      size_t suffix = RealizedPlatform.rfind("_app_extension");
      if (suffix != StringRef::npos)
        RealizedPlatform = RealizedPlatform.slice(0, suffix);
    }
  
    StringRef TargetPlatform = Context.getTargetInfo().getPlatformName();
  
    // Match the platform name.
    if (RealizedPlatform != TargetPlatform)
      return AR_Available;
  
    StringRef PrettyPlatformName
      = AvailabilityAttr::getPrettyPlatformName(ActualPlatform);
  
    if (PrettyPlatformName.empty())
      PrettyPlatformName = ActualPlatform;
  
    std::string HintMessage;
    if (!A->getMessage().empty()) {
      HintMessage = " - ";
      HintMessage += A->getMessage();
    }
    
    // Make sure that this declaration has not been marked 'unavailable'.
    if (A->getUnavailable()) {
      if (Message) {
        Message->clear();
        llvm37::raw_string_ostream Out(*Message);
        Out << "not available on " << PrettyPlatformName 
            << HintMessage;
      }
  
      return AR_Unavailable;
    }
  
    // Make sure that this declaration has already been introduced.
    if (!A->getIntroduced().empty() && 
        TargetMinVersion < A->getIntroduced()) {
      if (Message) {
        Message->clear();
        llvm37::raw_string_ostream Out(*Message);
        VersionTuple VTI(A->getIntroduced());
        VTI.UseDotAsSeparator();
        Out << "introduced in " << PrettyPlatformName << ' ' 
            << VTI << HintMessage;
      }
  
      return AR_NotYetIntroduced;
    }
  
    // Make sure that this declaration hasn't been obsoleted.
    if (!A->getObsoleted().empty() && TargetMinVersion >= A->getObsoleted()) {
      if (Message) {
        Message->clear();
        llvm37::raw_string_ostream Out(*Message);
        VersionTuple VTO(A->getObsoleted());
        VTO.UseDotAsSeparator();
        Out << "obsoleted in " << PrettyPlatformName << ' ' 
            << VTO << HintMessage;
      }
      
      return AR_Unavailable;
    }
  
    // Make sure that this declaration hasn't been deprecated.
    if (!A->getDeprecated().empty() && TargetMinVersion >= A->getDeprecated()) {
      if (Message) {
        Message->clear();
        llvm37::raw_string_ostream Out(*Message);
        VersionTuple VTD(A->getDeprecated());
        VTD.UseDotAsSeparator();
        Out << "first deprecated in " << PrettyPlatformName << ' '
            << VTD << HintMessage;
      }
      
      return AR_Deprecated;
    }
  
    return AR_Available;
  }
  
  AvailabilityResult Decl::getAvailability(std::string *Message) const {
    AvailabilityResult Result = AR_Available;
    std::string ResultMessage;
  
    for (const auto *A : attrs()) {
      if (const auto *Deprecated = dyn_cast<DeprecatedAttr>(A)) {
        if (Result >= AR_Deprecated)
          continue;
  
        if (Message)
          ResultMessage = Deprecated->getMessage();
  
        Result = AR_Deprecated;
        continue;
      }
  
      if (const auto *Unavailable = dyn_cast<UnavailableAttr>(A)) {
        if (Message)
          *Message = Unavailable->getMessage();
        return AR_Unavailable;
      }
  
      if (const auto *Availability = dyn_cast<AvailabilityAttr>(A)) {
        AvailabilityResult AR = CheckAvailability(getASTContext(), Availability,
                                                  Message);
  
        if (AR == AR_Unavailable)
          return AR_Unavailable;
  
        if (AR > Result) {
          Result = AR;
          if (Message)
            ResultMessage.swap(*Message);
        }
        continue;
      }
    }
  
    if (Message)
      Message->swap(ResultMessage);
    return Result;
  }
  
  bool Decl::canBeWeakImported(bool &IsDefinition) const {
    IsDefinition = false;
  
    // Variables, if they aren't definitions.
    if (const VarDecl *Var = dyn_cast<VarDecl>(this)) {
      if (Var->isThisDeclarationADefinition()) {
        IsDefinition = true;
        return false;
      }
      return true;
  
    // Functions, if they aren't definitions.
    } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(this)) {
      if (FD->hasBody()) {
        IsDefinition = true;
        return false;
      }
      return true;
  
    // Objective-C classes, if this is the non-fragile runtime.
    } else if (isa<ObjCInterfaceDecl>(this) &&
               getASTContext().getLangOpts().ObjCRuntime.hasWeakClassImport()) {
      return true;
  
    // Nothing else.
    } else {
      return false;
    }
  }
  
  bool Decl::isWeakImported() const {
    bool IsDefinition;
    if (!canBeWeakImported(IsDefinition))
      return false;
  
    for (const auto *A : attrs()) {
      if (isa<WeakImportAttr>(A))
        return true;
  
      if (const auto *Availability = dyn_cast<AvailabilityAttr>(A)) {
        if (CheckAvailability(getASTContext(), Availability,
                              nullptr) == AR_NotYetIntroduced)
          return true;
      }
    }
  
    return false;
  }
  
  unsigned Decl::getIdentifierNamespaceForKind(Kind DeclKind) {
    switch (DeclKind) {
      case Function:
      case CXXMethod:
      case CXXConstructor:
      case CXXDestructor:
      case CXXConversion:
      case EnumConstant:
      case Var:
      case ImplicitParam:
      case ParmVar:
      case NonTypeTemplateParm:
      case ObjCMethod:
      case ObjCProperty:
      case MSProperty:
        return IDNS_Ordinary;
      case Label:
        return IDNS_Label;
      case IndirectField:
        return IDNS_Ordinary | IDNS_Member;
  
      case ObjCCompatibleAlias:
      case ObjCInterface:
        return IDNS_Ordinary | IDNS_Type;
  
      case Typedef:
      case TypeAlias:
      case TypeAliasTemplate:
      case UnresolvedUsingTypename:
      case TemplateTypeParm:
      case ObjCTypeParam:
        return IDNS_Ordinary | IDNS_Type;
  
      case UsingShadow:
        return 0; // we'll actually overwrite this later
  
      case UnresolvedUsingValue:
        return IDNS_Ordinary | IDNS_Using;
  
      case Using:
        return IDNS_Using;
  
      case ObjCProtocol:
        return IDNS_ObjCProtocol;
  
      case Field:
      case ObjCAtDefsField:
      case ObjCIvar:
        return IDNS_Member;
  
      case Record:
      case CXXRecord:
      case Enum:
        return IDNS_Tag | IDNS_Type;
  
      case Namespace:
      case NamespaceAlias:
        return IDNS_Namespace;
  
      case FunctionTemplate:
      case VarTemplate:
        return IDNS_Ordinary;
  
      case ClassTemplate:
      case TemplateTemplateParm:
        return IDNS_Ordinary | IDNS_Tag | IDNS_Type;
  
      // Never have names.
      case Friend:
      case FriendTemplate:
      case AccessSpec:
      case LinkageSpec:
      case FileScopeAsm:
      case StaticAssert:
      case ObjCPropertyImpl:
      case Block:
      case Captured:
      case TranslationUnit:
      case ExternCContext:
  
      case UsingDirective:
      case ClassTemplateSpecialization:
      case ClassTemplatePartialSpecialization:
      case ClassScopeFunctionSpecialization:
      case VarTemplateSpecialization:
      case VarTemplatePartialSpecialization:
      case ObjCImplementation:
      case ObjCCategory:
      case ObjCCategoryImpl:
      case Import:
      case OMPThreadPrivate:
      case Empty:
      case HLSLBuffer: // HLSL Change
        // Never looked up by name.
        return 0;
    }
  
    llvm37_unreachable("Invalid DeclKind!");
  }
  
  void Decl::setAttrsImpl(const AttrVec &attrs, ASTContext &Ctx) {
    assert(!HasAttrs && "Decl already contains attrs.");
  
    AttrVec &AttrBlank = Ctx.getDeclAttrs(this);
    assert(AttrBlank.empty() && "HasAttrs was wrong?");
  
    AttrBlank = attrs;
    HasAttrs = true;
  }
  
  void Decl::dropAttrs() {
    if (!HasAttrs) return;
  
    HasAttrs = false;
    getASTContext().eraseDeclAttrs(this);
  }
  
  const AttrVec &Decl::getAttrs() const {
    assert(HasAttrs && "No attrs to get!");
    return getASTContext().getDeclAttrs(this);
  }
  
  Decl *Decl::castFromDeclContext (const DeclContext *D) {
    Decl::Kind DK = D->getDeclKind();
    switch(DK) {
  #define DECL(NAME, BASE)
  #define DECL_CONTEXT(NAME) \
      case Decl::NAME:       \
        return static_cast<NAME##Decl*>(const_cast<DeclContext*>(D));
  #define DECL_CONTEXT_BASE(NAME)
  #include "clang/AST/DeclNodes.inc"
      default:
  #define DECL(NAME, BASE)
  #define DECL_CONTEXT_BASE(NAME)                  \
        if (DK >= first##NAME && DK <= last##NAME) \
          return static_cast<NAME##Decl*>(const_cast<DeclContext*>(D));
  #include "clang/AST/DeclNodes.inc"
        llvm37_unreachable("a decl that inherits DeclContext isn't handled");
    }
  }
  
  DeclContext *Decl::castToDeclContext(const Decl *D) {
    Decl::Kind DK = D->getKind();
    switch(DK) {
  #define DECL(NAME, BASE)
  #define DECL_CONTEXT(NAME) \
      case Decl::NAME:       \
        return static_cast<NAME##Decl*>(const_cast<Decl*>(D));
  #define DECL_CONTEXT_BASE(NAME)
  #include "clang/AST/DeclNodes.inc"
      default:
  #define DECL(NAME, BASE)
  #define DECL_CONTEXT_BASE(NAME)                                   \
        if (DK >= first##NAME && DK <= last##NAME)                  \
          return static_cast<NAME##Decl*>(const_cast<Decl*>(D));
  #include "clang/AST/DeclNodes.inc"
        llvm37_unreachable("a decl that inherits DeclContext isn't handled");
    }
  }
  
  SourceLocation Decl::getBodyRBrace() const {
    // Special handling of FunctionDecl to avoid de-serializing the body from PCH.
    // FunctionDecl stores EndRangeLoc for this purpose.
    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(this)) {
      const FunctionDecl *Definition;
      if (FD->hasBody(Definition))
        return Definition->getSourceRange().getEnd();
      return SourceLocation();
    }
  
    if (Stmt *Body = getBody())
      return Body->getSourceRange().getEnd();
  
    return SourceLocation();
  }
  
  bool Decl::AccessDeclContextSanity() const {
  #ifndef NDEBUG
    // Suppress this check if any of the following hold:
    // 1. this is the translation unit (and thus has no parent)
    // 2. this is a template parameter (and thus doesn't belong to its context)
    // 3. this is a non-type template parameter
    // 4. the context is not a record
    // 5. it's invalid
    // 6. it's a C++0x static_assert.
    if (isa<TranslationUnitDecl>(this) ||
        isa<TemplateTypeParmDecl>(this) ||
        isa<NonTypeTemplateParmDecl>(this) ||
        !isa<CXXRecordDecl>(getDeclContext()) ||
        isInvalidDecl() ||
        isa<StaticAssertDecl>(this) ||
        // FIXME: a ParmVarDecl can have ClassTemplateSpecialization
        // as DeclContext (?).
        isa<ParmVarDecl>(this) ||
        // FIXME: a ClassTemplateSpecialization or CXXRecordDecl can have
        // AS_none as access specifier.
        isa<CXXRecordDecl>(this) ||
        isa<ClassScopeFunctionSpecializationDecl>(this))
      return true;
  
    assert(Access != AS_none &&
           "Access specifier is AS_none inside a record decl");
  #endif
    return true;
  }
  
  static Decl::Kind getKind(const Decl *D) { return D->getKind(); }
  static Decl::Kind getKind(const DeclContext *DC) { return DC->getDeclKind(); }
  
  const FunctionType *Decl::getFunctionType(bool BlocksToo) const {
    QualType Ty;
    if (const ValueDecl *D = dyn_cast<ValueDecl>(this))
      Ty = D->getType();
    else if (const TypedefNameDecl *D = dyn_cast<TypedefNameDecl>(this))
      Ty = D->getUnderlyingType();
    else
      return nullptr;
  
    if (Ty->isFunctionPointerType())
      Ty = Ty->getAs<PointerType>()->getPointeeType();
    else if (BlocksToo && Ty->isBlockPointerType())
      Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
  
    return Ty->getAs<FunctionType>();
  }
  
  
  /// Starting at a given context (a Decl or DeclContext), look for a
  /// code context that is not a closure (a lambda, block, etc.).
  template <class T> static Decl *getNonClosureContext(T *D) {
    if (getKind(D) == Decl::CXXMethod) {
      CXXMethodDecl *MD = cast<CXXMethodDecl>(D);
      if (MD->getOverloadedOperator() == OO_Call &&
          MD->getParent()->isLambda())
        return getNonClosureContext(MD->getParent()->getParent());
      return MD;
    } else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
      return FD;
    } else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
      return MD;
    } else if (BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
      return getNonClosureContext(BD->getParent());
    } else if (CapturedDecl *CD = dyn_cast<CapturedDecl>(D)) {
      return getNonClosureContext(CD->getParent());
    } else {
      return nullptr;
    }
  }
  
  Decl *Decl::getNonClosureContext() {
    return ::getNonClosureContext(this);
  }
  
  Decl *DeclContext::getNonClosureAncestor() {
    return ::getNonClosureContext(this);
  }
  
  //===----------------------------------------------------------------------===//
  // DeclContext Implementation
  //===----------------------------------------------------------------------===//
  
  bool DeclContext::classof(const Decl *D) {
    switch (D->getKind()) {
  #define DECL(NAME, BASE)
  #define DECL_CONTEXT(NAME) case Decl::NAME:
  #define DECL_CONTEXT_BASE(NAME)
  #include "clang/AST/DeclNodes.inc"
        return true;
      default:
  #define DECL(NAME, BASE)
  #define DECL_CONTEXT_BASE(NAME)                 \
        if (D->getKind() >= Decl::first##NAME &&  \
            D->getKind() <= Decl::last##NAME)     \
          return true;
  #include "clang/AST/DeclNodes.inc"
        return false;
    }
  }
  
  DeclContext::~DeclContext() { }
  
  /// \brief Find the parent context of this context that will be
  /// used for unqualified name lookup.
  ///
  /// Generally, the parent lookup context is the semantic context. However, for
  /// a friend function the parent lookup context is the lexical context, which
  /// is the class in which the friend is declared.
  DeclContext *DeclContext::getLookupParent() {
    // FIXME: Find a better way to identify friends
    if (isa<FunctionDecl>(this))
      if (getParent()->getRedeclContext()->isFileContext() &&
          getLexicalParent()->getRedeclContext()->isRecord())
        return getLexicalParent();
    
    return getParent();
  }
  
  bool DeclContext::isInlineNamespace() const {
    return isNamespace() &&
           cast<NamespaceDecl>(this)->isInline();
  }
  
  bool DeclContext::isStdNamespace() const {
    if (!isNamespace())
      return false;
  
    const NamespaceDecl *ND = cast<NamespaceDecl>(this);
    if (ND->isInline()) {
      return ND->getParent()->isStdNamespace();
    }
  
    if (!getParent()->getRedeclContext()->isTranslationUnit())
      return false;
  
    const IdentifierInfo *II = ND->getIdentifier();
    return II && II->isStr("std");
  }
  
  bool DeclContext::isDependentContext() const {
    if (isFileContext())
      return false;
  
    if (isa<ClassTemplatePartialSpecializationDecl>(this))
      return true;
  
    if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(this)) {
      if (Record->getDescribedClassTemplate())
        return true;
      
      if (Record->isDependentLambda())
        return true;
    }
    
    if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(this)) {
      if (Function->getDescribedFunctionTemplate())
        return true;
  
      // Friend function declarations are dependent if their *lexical*
      // context is dependent.
      if (cast<Decl>(this)->getFriendObjectKind())
        return getLexicalParent()->isDependentContext();
    }
  
    // FIXME: A variable template is a dependent context, but is not a
    // DeclContext. A context within it (such as a lambda-expression)
    // should be considered dependent.
  
    return getParent() && getParent()->isDependentContext();
  }
  
  bool DeclContext::isTransparentContext() const {
    if (DeclKind == Decl::Enum)
      return !cast<EnumDecl>(this)->isScoped();
    else if (DeclKind == Decl::LinkageSpec)
      return true;
  
    // HLSL Change Starts
    if (DeclKind == Decl::HLSLBuffer)
      return true;
    // HLSL Change Ends
  
    return false;
  }
  
  static bool isLinkageSpecContext(const DeclContext *DC,
                                   LinkageSpecDecl::LanguageIDs ID) {
    while (DC->getDeclKind() != Decl::TranslationUnit) {
      if (DC->getDeclKind() == Decl::LinkageSpec)
        return cast<LinkageSpecDecl>(DC)->getLanguage() == ID;
      DC = DC->getLexicalParent();
    }
    return false;
  }
  
  bool DeclContext::isExternCContext() const {
    return isLinkageSpecContext(this, clang::LinkageSpecDecl::lang_c);
  }
  
  bool DeclContext::isExternCXXContext() const {
    return isLinkageSpecContext(this, clang::LinkageSpecDecl::lang_cxx);
  }
  
  bool DeclContext::Encloses(const DeclContext *DC) const {
    if (getPrimaryContext() != this)
      return getPrimaryContext()->Encloses(DC);
  
    for (; DC; DC = DC->getParent())
      if (DC->getPrimaryContext() == this)
        return true;
    return false;
  }
  
  DeclContext *DeclContext::getPrimaryContext() {
    switch (DeclKind) {
    case Decl::TranslationUnit:
    case Decl::ExternCContext:
    case Decl::LinkageSpec:
    case Decl::Block:
    case Decl::Captured:
      // There is only one DeclContext for these entities.
      return this;
  
    // HLSL Change Starts
    case Decl::HLSLBuffer:
      // Each buffer, even with the same name, is a distinct construct.
      return this;
    // HLSL Change Ends
  
    case Decl::Namespace:
      // The original namespace is our primary context.
      return static_cast<NamespaceDecl*>(this)->getOriginalNamespace();
  
    case Decl::ObjCMethod:
      return this;
  
    case Decl::ObjCInterface:
      if (ObjCInterfaceDecl *Def = cast<ObjCInterfaceDecl>(this)->getDefinition())
        return Def;
        
      return this;
        
    case Decl::ObjCProtocol:
      if (ObjCProtocolDecl *Def = cast<ObjCProtocolDecl>(this)->getDefinition())
        return Def;
      
      return this;
        
    case Decl::ObjCCategory:
      return this;
  
    case Decl::ObjCImplementation:
    case Decl::ObjCCategoryImpl:
      return this;
  
    default:
      if (DeclKind >= Decl::firstTag && DeclKind <= Decl::lastTag) {
        // If this is a tag type that has a definition or is currently
        // being defined, that definition is our primary context.
        TagDecl *Tag = cast<TagDecl>(this);
  
        if (TagDecl *Def = Tag->getDefinition())
          return Def;
  
        if (const TagType *TagTy = dyn_cast<TagType>(Tag->getTypeForDecl())) {
          // Note, TagType::getDecl returns the (partial) definition one exists.
          TagDecl *PossiblePartialDef = TagTy->getDecl();
          if (PossiblePartialDef->isBeingDefined())
            return PossiblePartialDef;
        } else {
          assert(isa<InjectedClassNameType>(Tag->getTypeForDecl()));
        }
  
        return Tag;
      }
  
      assert(DeclKind >= Decl::firstFunction && DeclKind <= Decl::lastFunction &&
            "Unknown DeclContext kind");
      return this;
    }
  }
  
  void 
  DeclContext::collectAllContexts(SmallVectorImpl<DeclContext *> &Contexts){
    Contexts.clear();
    
    if (DeclKind != Decl::Namespace) {
      Contexts.push_back(this);
      return;
    }
    
    NamespaceDecl *Self = static_cast<NamespaceDecl *>(this);
    for (NamespaceDecl *N = Self->getMostRecentDecl(); N;
         N = N->getPreviousDecl())
      Contexts.push_back(N);
    
    std::reverse(Contexts.begin(), Contexts.end());
  }
  
  std::pair<Decl *, Decl *>
  DeclContext::BuildDeclChain(ArrayRef<Decl*> Decls,
                              bool FieldsAlreadyLoaded) {
    // Build up a chain of declarations via the Decl::NextInContextAndBits field.
    Decl *FirstNewDecl = nullptr;
    Decl *PrevDecl = nullptr;
    for (unsigned I = 0, N = Decls.size(); I != N; ++I) {
      if (FieldsAlreadyLoaded && isa<FieldDecl>(Decls[I]))
        continue;
  
      Decl *D = Decls[I];
      if (PrevDecl)
        PrevDecl->NextInContextAndBits.setPointer(D);
      else
        FirstNewDecl = D;
  
      PrevDecl = D;
    }
  
    return std::make_pair(FirstNewDecl, PrevDecl);
  }
  
  /// \brief We have just acquired external visible storage, and we already have
  /// built a lookup map. For every name in the map, pull in the new names from
  /// the external storage.
  void DeclContext::reconcileExternalVisibleStorage() const {
    assert(NeedToReconcileExternalVisibleStorage && LookupPtr);
    NeedToReconcileExternalVisibleStorage = false;
  
    for (auto &Lookup : *LookupPtr)
      Lookup.second.setHasExternalDecls();
  }
  
  /// \brief Load the declarations within this lexical storage from an
  /// external source.
  /// \return \c true if any declarations were added.
  bool
  DeclContext::LoadLexicalDeclsFromExternalStorage() const {
    ExternalASTSource *Source = getParentASTContext().getExternalSource();
    assert(hasExternalLexicalStorage() && Source && "No external storage?");
  
    // Notify that we have a DeclContext that is initializing.
    ExternalASTSource::Deserializing ADeclContext(Source);
  
    // Load the external declarations, if any.
    SmallVector<Decl*, 64> Decls;
    ExternalLexicalStorage = false;
    switch (Source->FindExternalLexicalDecls(this, Decls)) {
    case ELR_Success:
      break;
      
    case ELR_Failure:
    case ELR_AlreadyLoaded:
      return false;
    }
  
    if (Decls.empty())
      return false;
  
    // We may have already loaded just the fields of this record, in which case
    // we need to ignore them.
    bool FieldsAlreadyLoaded = false;
    if (const RecordDecl *RD = dyn_cast<RecordDecl>(this))
      FieldsAlreadyLoaded = RD->LoadedFieldsFromExternalStorage;
    
    // Splice the newly-read declarations into the beginning of the list
    // of declarations.
    Decl *ExternalFirst, *ExternalLast;
    std::tie(ExternalFirst, ExternalLast) =
        BuildDeclChain(Decls, FieldsAlreadyLoaded);
    ExternalLast->NextInContextAndBits.setPointer(FirstDecl);
    FirstDecl = ExternalFirst;
    if (!LastDecl)
      LastDecl = ExternalLast;
    return true;
  }
  
  DeclContext::lookup_result
  ExternalASTSource::SetNoExternalVisibleDeclsForName(const DeclContext *DC,
                                                      DeclarationName Name) {
    ASTContext &Context = DC->getParentASTContext();
    StoredDeclsMap *Map;
    if (!(Map = DC->LookupPtr))
      Map = DC->CreateStoredDeclsMap(Context);
    if (DC->NeedToReconcileExternalVisibleStorage)
      DC->reconcileExternalVisibleStorage();
  
    (*Map)[Name].removeExternalDecls();
  
    return DeclContext::lookup_result();
  }
  
  DeclContext::lookup_result
  ExternalASTSource::SetExternalVisibleDeclsForName(const DeclContext *DC,
                                                    DeclarationName Name,
                                                    ArrayRef<NamedDecl*> Decls) {
    ASTContext &Context = DC->getParentASTContext();
    StoredDeclsMap *Map;
    if (!(Map = DC->LookupPtr))
      Map = DC->CreateStoredDeclsMap(Context);
    if (DC->NeedToReconcileExternalVisibleStorage)
      DC->reconcileExternalVisibleStorage();
  
    StoredDeclsList &List = (*Map)[Name];
  
    // Clear out any old external visible declarations, to avoid quadratic
    // performance in the redeclaration checks below.
    List.removeExternalDecls();
  
    if (!List.isNull()) {
      // We have both existing declarations and new declarations for this name.
      // Some of the declarations may simply replace existing ones. Handle those
      // first.
      llvm37::SmallVector<unsigned, 8> Skip;
      for (unsigned I = 0, N = Decls.size(); I != N; ++I)
        if (List.HandleRedeclaration(Decls[I], /*IsKnownNewer*/false))
          Skip.push_back(I);
      Skip.push_back(Decls.size());
  
      // Add in any new declarations.
      unsigned SkipPos = 0;
      for (unsigned I = 0, N = Decls.size(); I != N; ++I) {
        if (I == Skip[SkipPos])
          ++SkipPos;
        else
          List.AddSubsequentDecl(Decls[I]);
      }
    } else {
      // Convert the array to a StoredDeclsList.
      for (ArrayRef<NamedDecl*>::iterator
             I = Decls.begin(), E = Decls.end(); I != E; ++I) {
        if (List.isNull())
          List.setOnlyValue(*I);
        else
          List.AddSubsequentDecl(*I);
      }
    }
  
    return List.getLookupResult();
  }
  
  DeclContext::decl_iterator DeclContext::decls_begin() const {
    if (hasExternalLexicalStorage())
      LoadLexicalDeclsFromExternalStorage();
    return decl_iterator(FirstDecl);
  }
  
  bool DeclContext::decls_empty() const {
    if (hasExternalLexicalStorage())
      LoadLexicalDeclsFromExternalStorage();
  
    return !FirstDecl;
  }
  
  bool DeclContext::containsDecl(Decl *D) const {
    return (D->getLexicalDeclContext() == this &&
            (D->NextInContextAndBits.getPointer() || D == LastDecl));
  }
  
  void DeclContext::removeDecl(Decl *D) {
    assert(D->getLexicalDeclContext() == this &&
           "decl being removed from non-lexical context");
    assert((D->NextInContextAndBits.getPointer() || D == LastDecl) &&
           "decl is not in decls list");
  
    // Remove D from the decl chain.  This is O(n) but hopefully rare.
    if (D == FirstDecl) {
      if (D == LastDecl)
        FirstDecl = LastDecl = nullptr;
      else
        FirstDecl = D->NextInContextAndBits.getPointer();
    } else {
      for (Decl *I = FirstDecl; true; I = I->NextInContextAndBits.getPointer()) {
        assert(I && "decl not found in linked list");
        if (I->NextInContextAndBits.getPointer() == D) {
          I->NextInContextAndBits.setPointer(D->NextInContextAndBits.getPointer());
          if (D == LastDecl) LastDecl = I;
          break;
        }
      }
    }
    
    // Mark that D is no longer in the decl chain.
    D->NextInContextAndBits.setPointer(nullptr);
  
    // Remove D from the lookup table if necessary.
    if (isa<NamedDecl>(D)) {
      NamedDecl *ND = cast<NamedDecl>(D);
  
      // Remove only decls that have a name
      if (!ND->getDeclName()) return;
  
      StoredDeclsMap *Map = getPrimaryContext()->LookupPtr;
      if (!Map) return;
  
      StoredDeclsMap::iterator Pos = Map->find(ND->getDeclName());
      assert(Pos != Map->end() && "no lookup entry for decl");
      if (Pos->second.getAsVector() || Pos->second.getAsDecl() == ND)
        Pos->second.remove(ND);
    }
  }
  
  void DeclContext::addHiddenDecl(Decl *D) {
    assert(D->getLexicalDeclContext() == this &&
           "Decl inserted into wrong lexical context");
    assert(!D->getNextDeclInContext() && D != LastDecl &&
           "Decl already inserted into a DeclContext");
  
    if (FirstDecl) {
      LastDecl->NextInContextAndBits.setPointer(D);
      LastDecl = D;
    } else {
      FirstDecl = LastDecl = D;
    }
  
    // Notify a C++ record declaration that we've added a member, so it can
    // update it's class-specific state.
    if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(this))
      Record->addedMember(D);
  
    // If this is a newly-created (not de-serialized) import declaration, wire
    // it in to the list of local import declarations.
    if (!D->isFromASTFile()) {
      if (ImportDecl *Import = dyn_cast<ImportDecl>(D))
        D->getASTContext().addedLocalImportDecl(Import);
    }
  }
  
  void DeclContext::addDecl(Decl *D) {
    addHiddenDecl(D);
  
    if (NamedDecl *ND = dyn_cast<NamedDecl>(D))
      ND->getDeclContext()->getPrimaryContext()->
          makeDeclVisibleInContextWithFlags(ND, false, true);
  }
  
  void DeclContext::addDeclInternal(Decl *D) {
    addHiddenDecl(D);
  
    if (NamedDecl *ND = dyn_cast<NamedDecl>(D))
      ND->getDeclContext()->getPrimaryContext()->
          makeDeclVisibleInContextWithFlags(ND, true, true);
  }
  
  /// shouldBeHidden - Determine whether a declaration which was declared
  /// within its semantic context should be invisible to qualified name lookup.
  static bool shouldBeHidden(NamedDecl *D) {
    // Skip unnamed declarations.
    if (!D->getDeclName())
      return true;
  
    // Skip entities that can't be found by name lookup into a particular
    // context.
    if ((D->getIdentifierNamespace() == 0 && !isa<UsingDirectiveDecl>(D)) ||
        D->isTemplateParameter())
      return true;
  
    // Skip template specializations.
    // FIXME: This feels like a hack. Should DeclarationName support
    // template-ids, or is there a better way to keep specializations
    // from being visible?
    if (isa<ClassTemplateSpecializationDecl>(D))
      return true;
    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
      if (FD->isFunctionTemplateSpecialization())
        return true;
  
    return false;
  }
  
  /// buildLookup - Build the lookup data structure with all of the
  /// declarations in this DeclContext (and any other contexts linked
  /// to it or transparent contexts nested within it) and return it.
  ///
  /// Note that the produced map may miss out declarations from an
  /// external source. If it does, those entries will be marked with
  /// the 'hasExternalDecls' flag.
  StoredDeclsMap *DeclContext::buildLookup() {
    assert(this == getPrimaryContext() && "buildLookup called on non-primary DC");
  
    if (!HasLazyLocalLexicalLookups && !HasLazyExternalLexicalLookups)
      return LookupPtr;
  
    SmallVector<DeclContext *, 2> Contexts;
    collectAllContexts(Contexts);
  
    if (HasLazyExternalLexicalLookups) {
      HasLazyExternalLexicalLookups = false;
      for (auto *DC : Contexts) {
        if (DC->hasExternalLexicalStorage())
          HasLazyLocalLexicalLookups |=
              DC->LoadLexicalDeclsFromExternalStorage();
      }
  
      if (!HasLazyLocalLexicalLookups)
        return LookupPtr;
    }
  
    for (auto *DC : Contexts)
      buildLookupImpl(DC, hasExternalVisibleStorage());
  
    // We no longer have any lazy decls.
    HasLazyLocalLexicalLookups = false;
    return LookupPtr;
  }
  
  /// buildLookupImpl - Build part of the lookup data structure for the
  /// declarations contained within DCtx, which will either be this
  /// DeclContext, a DeclContext linked to it, or a transparent context
  /// nested within it.
  void DeclContext::buildLookupImpl(DeclContext *DCtx, bool Internal) {
    for (Decl *D : DCtx->noload_decls()) {
      // Insert this declaration into the lookup structure, but only if
      // it's semantically within its decl context. Any other decls which
      // should be found in this context are added eagerly.
      //
      // If it's from an AST file, don't add it now. It'll get handled by
      // FindExternalVisibleDeclsByName if needed. Exception: if we're not
      // in C++, we do not track external visible decls for the TU, so in
      // that case we need to collect them all here.
      if (NamedDecl *ND = dyn_cast<NamedDecl>(D))
        if (ND->getDeclContext() == DCtx && !shouldBeHidden(ND) &&
            (!ND->isFromASTFile() ||
             (isTranslationUnit() &&
              !getParentASTContext().getLangOpts().CPlusPlus)))
          makeDeclVisibleInContextImpl(ND, Internal);
  
      // If this declaration is itself a transparent declaration context
      // or inline namespace, add the members of this declaration of that
      // context (recursively).
      if (DeclContext *InnerCtx = dyn_cast<DeclContext>(D))
        if (InnerCtx->isTransparentContext() || InnerCtx->isInlineNamespace())
          buildLookupImpl(InnerCtx, Internal);
    }
  }
  
  NamedDecl *const DeclContextLookupResult::SingleElementDummyList = nullptr;
  
  DeclContext::lookup_result
  DeclContext::lookup(DeclarationName Name) const {
    assert(DeclKind != Decl::LinkageSpec &&
           "Should not perform lookups into linkage specs!");
  
    const DeclContext *PrimaryContext = getPrimaryContext();
    if (PrimaryContext != this)
      return PrimaryContext->lookup(Name);
  
    // If we have an external source, ensure that any later redeclarations of this
    // context have been loaded, since they may add names to the result of this
    // lookup (or add external visible storage).
    ExternalASTSource *Source = getParentASTContext().getExternalSource();
    if (Source)
      (void)cast<Decl>(this)->getMostRecentDecl();
  
    if (hasExternalVisibleStorage()) {
      assert(Source && "external visible storage but no external source?");
  
      if (NeedToReconcileExternalVisibleStorage)
        reconcileExternalVisibleStorage();
  
      StoredDeclsMap *Map = LookupPtr;
  
      if (HasLazyLocalLexicalLookups || HasLazyExternalLexicalLookups)
        // FIXME: Make buildLookup const?
        Map = const_cast<DeclContext*>(this)->buildLookup();
  
      if (!Map)
        Map = CreateStoredDeclsMap(getParentASTContext());
  
      // If we have a lookup result with no external decls, we are done.
      std::pair<StoredDeclsMap::iterator, bool> R =
          Map->insert(std::make_pair(Name, StoredDeclsList()));
      if (!R.second && !R.first->second.hasExternalDecls())
        return R.first->second.getLookupResult();
  
      if (Source->FindExternalVisibleDeclsByName(this, Name) || !R.second) {
        if (StoredDeclsMap *Map = LookupPtr) {
          StoredDeclsMap::iterator I = Map->find(Name);
          if (I != Map->end())
            return I->second.getLookupResult();
        }
      }
  
      return lookup_result();
    }
  
    StoredDeclsMap *Map = LookupPtr;
    if (HasLazyLocalLexicalLookups || HasLazyExternalLexicalLookups)
      Map = const_cast<DeclContext*>(this)->buildLookup();
  
    if (!Map)
      return lookup_result();
  
    StoredDeclsMap::iterator I = Map->find(Name);
    if (I == Map->end())
      return lookup_result();
  
    return I->second.getLookupResult();
  }
  
  DeclContext::lookup_result
  DeclContext::noload_lookup(DeclarationName Name) {
    assert(DeclKind != Decl::LinkageSpec &&
           "Should not perform lookups into linkage specs!");
  
    DeclContext *PrimaryContext = getPrimaryContext();
    if (PrimaryContext != this)
      return PrimaryContext->noload_lookup(Name);
  
    // If we have any lazy lexical declarations not in our lookup map, add them
    // now. Don't import any external declarations, not even if we know we have
    // some missing from the external visible lookups.
    if (HasLazyLocalLexicalLookups) {
      SmallVector<DeclContext *, 2> Contexts;
      collectAllContexts(Contexts);
      for (unsigned I = 0, N = Contexts.size(); I != N; ++I)
        buildLookupImpl(Contexts[I], hasExternalVisibleStorage());
      HasLazyLocalLexicalLookups = false;
    }
  
    StoredDeclsMap *Map = LookupPtr;
    if (!Map)
      return lookup_result();
  
    StoredDeclsMap::iterator I = Map->find(Name);
    return I != Map->end() ? I->second.getLookupResult()
                           : lookup_result();
  }
  
  void DeclContext::localUncachedLookup(DeclarationName Name,
                                        SmallVectorImpl<NamedDecl *> &Results) {
    Results.clear();
    
    // If there's no external storage, just perform a normal lookup and copy
    // the results.
    if (!hasExternalVisibleStorage() && !hasExternalLexicalStorage() && Name) {
      lookup_result LookupResults = lookup(Name);
      Results.insert(Results.end(), LookupResults.begin(), LookupResults.end());
      return;
    }
  
    // If we have a lookup table, check there first. Maybe we'll get lucky.
    // FIXME: Should we be checking these flags on the primary context?
    if (Name && !HasLazyLocalLexicalLookups && !HasLazyExternalLexicalLookups) {
      if (StoredDeclsMap *Map = LookupPtr) {
        StoredDeclsMap::iterator Pos = Map->find(Name);
        if (Pos != Map->end()) {
          Results.insert(Results.end(),
                         Pos->second.getLookupResult().begin(),
                         Pos->second.getLookupResult().end());
          return;
        }
      }
    }
  
    // Slow case: grovel through the declarations in our chain looking for 
    // matches.
    // FIXME: If we have lazy external declarations, this will not find them!
    // FIXME: Should we CollectAllContexts and walk them all here?
    for (Decl *D = FirstDecl; D; D = D->getNextDeclInContext()) {
      if (NamedDecl *ND = dyn_cast<NamedDecl>(D))
        if (ND->getDeclName() == Name)
          Results.push_back(ND);
    }
  }
  
  DeclContext *DeclContext::getRedeclContext() {
    DeclContext *Ctx = this;
    // Skip through transparent contexts.
    while (Ctx->isTransparentContext())
      Ctx = Ctx->getParent();
    return Ctx;
  }
  
  DeclContext *DeclContext::getEnclosingNamespaceContext() {
    DeclContext *Ctx = this;
    // Skip through non-namespace, non-translation-unit contexts.
    while (!Ctx->isFileContext())
      Ctx = Ctx->getParent();
    return Ctx->getPrimaryContext();
  }
  
  RecordDecl *DeclContext::getOuterLexicalRecordContext() {
    // Loop until we find a non-record context.
    RecordDecl *OutermostRD = nullptr;
    DeclContext *DC = this;
    while (DC->isRecord()) {
      OutermostRD = cast<RecordDecl>(DC);
      DC = DC->getLexicalParent();
    }
    return OutermostRD;
  }
  
  bool DeclContext::InEnclosingNamespaceSetOf(const DeclContext *O) const {
    // For non-file contexts, this is equivalent to Equals.
    if (!isFileContext())
      return O->Equals(this);
  
    do {
      if (O->Equals(this))
        return true;
  
      const NamespaceDecl *NS = dyn_cast<NamespaceDecl>(O);
      if (!NS || !NS->isInline())
        break;
      O = NS->getParent();
    } while (O);
  
    return false;
  }
  
  void DeclContext::makeDeclVisibleInContext(NamedDecl *D) {
    DeclContext *PrimaryDC = this->getPrimaryContext();
    DeclContext *DeclDC = D->getDeclContext()->getPrimaryContext();
    // If the decl is being added outside of its semantic decl context, we
    // need to ensure that we eagerly build the lookup information for it.
    PrimaryDC->makeDeclVisibleInContextWithFlags(D, false, PrimaryDC == DeclDC);
  }
  
  void DeclContext::makeDeclVisibleInContextWithFlags(NamedDecl *D, bool Internal,
                                                      bool Recoverable) {
    assert(this == getPrimaryContext() && "expected a primary DC");
  
    // Skip declarations within functions.
    if (isFunctionOrMethod())
      return;
  
    // Skip declarations which should be invisible to name lookup.
    if (shouldBeHidden(D))
      return;
  
    // If we already have a lookup data structure, perform the insertion into
    // it. If we might have externally-stored decls with this name, look them
    // up and perform the insertion. If this decl was declared outside its
    // semantic context, buildLookup won't add it, so add it now.
    //
    // FIXME: As a performance hack, don't add such decls into the translation
    // unit unless we're in C++, since qualified lookup into the TU is never
    // performed.
    if (LookupPtr || hasExternalVisibleStorage() ||
        ((!Recoverable || D->getDeclContext() != D->getLexicalDeclContext()) &&
         (getParentASTContext().getLangOpts().CPlusPlus ||
          !isTranslationUnit()))) {
      // If we have lazily omitted any decls, they might have the same name as
      // the decl which we are adding, so build a full lookup table before adding
      // this decl.
      buildLookup();
      makeDeclVisibleInContextImpl(D, Internal);
    } else {
      HasLazyLocalLexicalLookups = true;
    }
  
    // If we are a transparent context or inline namespace, insert into our
    // parent context, too. This operation is recursive.
    if (isTransparentContext() || isInlineNamespace())
      getParent()->getPrimaryContext()->
          makeDeclVisibleInContextWithFlags(D, Internal, Recoverable);
  
    Decl *DCAsDecl = cast<Decl>(this);
    // Notify that a decl was made visible unless we are a Tag being defined.
    if (!(isa<TagDecl>(DCAsDecl) && cast<TagDecl>(DCAsDecl)->isBeingDefined()))
      if (ASTMutationListener *L = DCAsDecl->getASTMutationListener())
        L->AddedVisibleDecl(this, D);
  }
  
  void DeclContext::makeDeclVisibleInContextImpl(NamedDecl *D, bool Internal) {
    // Find or create the stored declaration map.
    StoredDeclsMap *Map = LookupPtr;
    if (!Map) {
      ASTContext *C = &getParentASTContext();
      Map = CreateStoredDeclsMap(*C);
    }
  
    // If there is an external AST source, load any declarations it knows about
    // with this declaration's name.
    // If the lookup table contains an entry about this name it means that we
    // have already checked the external source.
    if (!Internal)
      if (ExternalASTSource *Source = getParentASTContext().getExternalSource())
        if (hasExternalVisibleStorage() &&
            Map->find(D->getDeclName()) == Map->end())
          Source->FindExternalVisibleDeclsByName(this, D->getDeclName());
  
    // Insert this declaration into the map.
    StoredDeclsList &DeclNameEntries = (*Map)[D->getDeclName()];
  
    if (Internal) {
      // If this is being added as part of loading an external declaration,
      // this may not be the only external declaration with this name.
      // In this case, we never try to replace an existing declaration; we'll
      // handle that when we finalize the list of declarations for this name.
      DeclNameEntries.setHasExternalDecls();
      DeclNameEntries.AddSubsequentDecl(D);
      return;
    }
  
    if (DeclNameEntries.isNull()) {
      DeclNameEntries.setOnlyValue(D);
      return;
    }
  
    if (DeclNameEntries.HandleRedeclaration(D, /*IsKnownNewer*/!Internal)) {
      // This declaration has replaced an existing one for which
      // declarationReplaces returns true.
      return;
    }
  
    // Put this declaration into the appropriate slot.
    DeclNameEntries.AddSubsequentDecl(D);
  }
  
  UsingDirectiveDecl *DeclContext::udir_iterator::operator*() const {
    return cast<UsingDirectiveDecl>(*I);
  }
  
  /// Returns iterator range [First, Last) of UsingDirectiveDecls stored within
  /// this context.
  DeclContext::udir_range DeclContext::using_directives() const {
    // FIXME: Use something more efficient than normal lookup for using
    // directives. In C++, using directives are looked up more than anything else.
    lookup_result Result = lookup(UsingDirectiveDecl::getName());
    return udir_range(Result.begin(), Result.end());
  }
  
  //===----------------------------------------------------------------------===//
  // Creation and Destruction of StoredDeclsMaps.                               //
  //===----------------------------------------------------------------------===//
  
  StoredDeclsMap *DeclContext::CreateStoredDeclsMap(ASTContext &C) const {
    assert(!LookupPtr && "context already has a decls map");
    assert(getPrimaryContext() == this &&
           "creating decls map on non-primary context");
  
    StoredDeclsMap *M;
    bool Dependent = isDependentContext();
    if (Dependent)
      M = new DependentStoredDeclsMap();
    else
      M = new StoredDeclsMap();
    M->Previous = C.LastSDM;
    C.LastSDM = llvm37::PointerIntPair<StoredDeclsMap*,1>(M, Dependent);
    LookupPtr = M;
    return M;
  }
  
  void ASTContext::ReleaseDeclContextMaps() {
    // It's okay to delete DependentStoredDeclsMaps via a StoredDeclsMap
    // pointer because the subclass doesn't add anything that needs to
    // be deleted.
    StoredDeclsMap::DestroyAll(LastSDM.getPointer(), LastSDM.getInt());
  }
  
  void StoredDeclsMap::DestroyAll(StoredDeclsMap *Map, bool Dependent) {
    while (Map) {
      // Advance the iteration before we invalidate memory.
      llvm37::PointerIntPair<StoredDeclsMap*,1> Next = Map->Previous;
  
      if (Dependent)
        delete static_cast<DependentStoredDeclsMap*>(Map);
      else
        delete Map;
  
      Map = Next.getPointer();
      Dependent = Next.getInt();
    }
  }
  
  DependentDiagnostic *DependentDiagnostic::Create(ASTContext &C,
                                                   DeclContext *Parent,
                                             const PartialDiagnostic &PDiag) {
    assert(Parent->isDependentContext()
           && "cannot iterate dependent diagnostics of non-dependent context");
    Parent = Parent->getPrimaryContext();
    if (!Parent->LookupPtr)
      Parent->CreateStoredDeclsMap(C);
  
    DependentStoredDeclsMap *Map =
        static_cast<DependentStoredDeclsMap *>(Parent->LookupPtr);
  
    // Allocate the copy of the PartialDiagnostic via the ASTContext's
    // BumpPtrAllocator, rather than the ASTContext itself.
    PartialDiagnostic::Storage *DiagStorage = nullptr;
    if (PDiag.hasStorage())
      DiagStorage = new (C) PartialDiagnostic::Storage;
    
    DependentDiagnostic *DD = new (C) DependentDiagnostic(PDiag, DiagStorage);
  
    // TODO: Maybe we shouldn't reverse the order during insertion.
    DD->NextDiagnostic = Map->FirstDiagnostic;
    Map->FirstDiagnostic = DD;
  
    return DD;
  }
  