xref: /external/clang/include/clang/Sema/Sema.h

//===--- Sema.h - Semantic Analysis & AST Building --------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the Sema class, which performs semantic analysis and
// builds ASTs.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_SEMA_SEMA_H
#define LLVM_CLANG_SEMA_SEMA_H

#include "clang/Sema/Ownership.h"
#include "clang/Sema/AnalysisBasedWarnings.h"
#include "clang/Sema/IdentifierResolver.h"
#include "clang/Sema/ObjCMethodList.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/ExternalSemaSource.h"
#include "clang/Sema/LocInfoType.h"
#include "clang/Sema/TypoCorrection.h"
#include "clang/Sema/Weak.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/NSAPI.h"
#include "clang/Lex/ModuleLoader.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Basic/TemplateKinds.h"
#include "clang/Basic/TypeTraits.h"
#include "clang/Basic/ExpressionTraits.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include <deque>
#include <string>

namespace llvm {
  class APSInt;
  template <typename ValueT> struct DenseMapInfo;
  template <typename ValueT, typename ValueInfoT> class DenseSet;
  class SmallBitVector;
}

namespace clang {
  class ADLResult;
  class ASTConsumer;
  class ASTContext;
  class ASTMutationListener;
  class ASTReader;
  class ASTWriter;
  class ArrayType;
  class AttributeList;
  class BlockDecl;
  class CXXBasePath;
  class CXXBasePaths;
  class CXXBindTemporaryExpr;
  typedef SmallVector<CXXBaseSpecifier*, 4> CXXCastPath;
  class CXXConstructorDecl;
  class CXXConversionDecl;
  class CXXDestructorDecl;
  class CXXFieldCollector;
  class CXXMemberCallExpr;
  class CXXMethodDecl;
  class CXXScopeSpec;
  class CXXTemporary;
  class CXXTryStmt;
  class CallExpr;
  class ClassTemplateDecl;
  class ClassTemplatePartialSpecializationDecl;
  class ClassTemplateSpecializationDecl;
  class CodeCompleteConsumer;
  class CodeCompletionAllocator;
  class CodeCompletionTUInfo;
  class CodeCompletionResult;
  class Decl;
  class DeclAccessPair;
  class DeclContext;
  class DeclRefExpr;
  class DeclaratorDecl;
  class DeducedTemplateArgument;
  class DependentDiagnostic;
  class DesignatedInitExpr;
  class Designation;
  class EnumConstantDecl;
  class Expr;
  class ExtVectorType;
  class ExternalSemaSource;
  class FormatAttr;
  class FriendDecl;
  class FunctionDecl;
  class FunctionProtoType;
  class FunctionTemplateDecl;
  class ImplicitConversionSequence;
  class InitListExpr;
  class InitializationKind;
  class InitializationSequence;
  class InitializedEntity;
  class IntegerLiteral;
  class LabelStmt;
  class LambdaExpr;
  class LangOptions;
  class LocalInstantiationScope;
  class LookupResult;
  class MacroInfo;
  class MultiLevelTemplateArgumentList;
  class NamedDecl;
  class NonNullAttr;
  class ObjCCategoryDecl;
  class ObjCCategoryImplDecl;
  class ObjCCompatibleAliasDecl;
  class ObjCContainerDecl;
  class ObjCImplDecl;
  class ObjCImplementationDecl;
  class ObjCInterfaceDecl;
  class ObjCIvarDecl;
  template <class T> class ObjCList;
  class ObjCMessageExpr;
  class ObjCMethodDecl;
  class ObjCPropertyDecl;
  class ObjCProtocolDecl;
  class OverloadCandidateSet;
  class OverloadExpr;
  class ParenListExpr;
  class ParmVarDecl;
  class Preprocessor;
  class PseudoDestructorTypeStorage;
  class PseudoObjectExpr;
  class QualType;
  class StandardConversionSequence;
  class Stmt;
  class StringLiteral;
  class SwitchStmt;
  class TargetAttributesSema;
  class TemplateArgument;
  class TemplateArgumentList;
  class TemplateArgumentLoc;
  class TemplateDecl;
  class TemplateParameterList;
  class TemplatePartialOrderingContext;
  class TemplateTemplateParmDecl;
  class Token;
  class TypeAliasDecl;
  class TypedefDecl;
  class TypedefNameDecl;
  class TypeLoc;
  class UnqualifiedId;
  class UnresolvedLookupExpr;
  class UnresolvedMemberExpr;
  class UnresolvedSetImpl;
  class UnresolvedSetIterator;
  class UsingDecl;
  class UsingShadowDecl;
  class ValueDecl;
  class VarDecl;
  class VisibilityAttr;
  class VisibleDeclConsumer;
  class IndirectFieldDecl;

namespace sema {
  class AccessedEntity;
  class BlockScopeInfo;
  class CompoundScopeInfo;
  class DelayedDiagnostic;
  class FunctionScopeInfo;
  class LambdaScopeInfo;
  class PossiblyUnreachableDiag;
  class TemplateDeductionInfo;
}

// FIXME: No way to easily map from TemplateTypeParmTypes to
// TemplateTypeParmDecls, so we have this horrible PointerUnion.
typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType*, NamedDecl*>,
                  SourceLocation> UnexpandedParameterPack;

/// Sema - This implements semantic analysis and AST building for C.
class Sema {
  Sema(const Sema&);           // DO NOT IMPLEMENT
  void operator=(const Sema&); // DO NOT IMPLEMENT
  mutable const TargetAttributesSema* TheTargetAttributesSema;
public:
  typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
  typedef OpaquePtr<TemplateName> TemplateTy;
  typedef OpaquePtr<QualType> TypeTy;

  OpenCLOptions OpenCLFeatures;
  FPOptions FPFeatures;

  const LangOptions &LangOpts;
  Preprocessor &PP;
  ASTContext &Context;
  ASTConsumer &Consumer;
  DiagnosticsEngine &Diags;
  SourceManager &SourceMgr;

  /// \brief Flag indicating whether or not to collect detailed statistics.
  bool CollectStats;

  /// \brief Source of additional semantic information.
  ExternalSemaSource *ExternalSource;

  /// \brief Code-completion consumer.
  CodeCompleteConsumer *CodeCompleter;

  /// CurContext - This is the current declaration context of parsing.
  DeclContext *CurContext;

  /// \brief Generally null except when we temporarily switch decl contexts,
  /// like in \see ActOnObjCTemporaryExitContainerContext.
  DeclContext *OriginalLexicalContext;

  /// VAListTagName - The declaration name corresponding to __va_list_tag.
  /// This is used as part of a hack to omit that class from ADL results.
  DeclarationName VAListTagName;

  /// PackContext - Manages the stack for #pragma pack. An alignment
  /// of 0 indicates default alignment.
  void *PackContext; // Really a "PragmaPackStack*"

  bool MSStructPragmaOn; // True when #pragma ms_struct on

  /// VisContext - Manages the stack for #pragma GCC visibility.
  void *VisContext; // Really a "PragmaVisStack*"

  /// ExprNeedsCleanups - True if the current evaluation context
  /// requires cleanups to be run at its conclusion.
  bool ExprNeedsCleanups;

  /// ExprCleanupObjects - This is the stack of objects requiring
  /// cleanup that are created by the current full expression.  The
  /// element type here is ExprWithCleanups::Object.
  SmallVector<BlockDecl*, 8> ExprCleanupObjects;

  llvm::SmallPtrSet<Expr*, 8> MaybeODRUseExprs;

  /// \brief Stack containing information about each of the nested
  /// function, block, and method scopes that are currently active.
  ///
  /// This array is never empty.  Clients should ignore the first
  /// element, which is used to cache a single FunctionScopeInfo
  /// that's used to parse every top-level function.
  SmallVector<sema::FunctionScopeInfo *, 4> FunctionScopes;

  typedef LazyVector<TypedefNameDecl *, ExternalSemaSource,
                     &ExternalSemaSource::ReadExtVectorDecls, 2, 2>
    ExtVectorDeclsType;

  /// ExtVectorDecls - This is a list all the extended vector types. This allows
  /// us to associate a raw vector type with one of the ext_vector type names.
  /// This is only necessary for issuing pretty diagnostics.
  ExtVectorDeclsType ExtVectorDecls;

  /// \brief The set of types for which we have already complained about the
  /// definitions being hidden.
  ///
  /// This set is used to suppress redundant diagnostics.
  llvm::SmallPtrSet<NamedDecl *, 4> HiddenDefinitions;

  /// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
  OwningPtr<CXXFieldCollector> FieldCollector;

  typedef llvm::SmallPtrSet<const CXXRecordDecl*, 8> RecordDeclSetTy;

  /// PureVirtualClassDiagSet - a set of class declarations which we have
  /// emitted a list of pure virtual functions. Used to prevent emitting the
  /// same list more than once.
  OwningPtr<RecordDeclSetTy> PureVirtualClassDiagSet;

  /// ParsingInitForAutoVars - a set of declarations with auto types for which
  /// we are currently parsing the initializer.
  llvm::SmallPtrSet<const Decl*, 4> ParsingInitForAutoVars;

  /// \brief A mapping from external names to the most recent
  /// locally-scoped external declaration with that name.
  ///
  /// This map contains external declarations introduced in local
  /// scoped, e.g.,
  ///
  /// \code
  /// void f() {
  ///   void foo(int, int);
  /// }
  /// \endcode
  ///
  /// Here, the name "foo" will be associated with the declaration on
  /// "foo" within f. This name is not visible outside of
  /// "f". However, we still find it in two cases:
  ///
  ///   - If we are declaring another external with the name "foo", we
  ///     can find "foo" as a previous declaration, so that the types
  ///     of this external declaration can be checked for
  ///     compatibility.
  ///
  ///   - If we would implicitly declare "foo" (e.g., due to a call to
  ///     "foo" in C when no prototype or definition is visible), then
  ///     we find this declaration of "foo" and complain that it is
  ///     not visible.
  llvm::DenseMap<DeclarationName, NamedDecl *> LocallyScopedExternalDecls;

  /// \brief Look for a locally scoped external declaration by the given name.
  llvm::DenseMap<DeclarationName, NamedDecl *>::iterator
  findLocallyScopedExternalDecl(DeclarationName Name);

  typedef LazyVector<VarDecl *, ExternalSemaSource,
                     &ExternalSemaSource::ReadTentativeDefinitions, 2, 2>
    TentativeDefinitionsType;

  /// \brief All the tentative definitions encountered in the TU.
  TentativeDefinitionsType TentativeDefinitions;

  typedef LazyVector<const DeclaratorDecl *, ExternalSemaSource,
                     &ExternalSemaSource::ReadUnusedFileScopedDecls, 2, 2>
    UnusedFileScopedDeclsType;

  /// \brief The set of file scoped decls seen so far that have not been used
  /// and must warn if not used. Only contains the first declaration.
  UnusedFileScopedDeclsType UnusedFileScopedDecls;

  typedef LazyVector<CXXConstructorDecl *, ExternalSemaSource,
                     &ExternalSemaSource::ReadDelegatingConstructors, 2, 2>
    DelegatingCtorDeclsType;

  /// \brief All the delegating constructors seen so far in the file, used for
  /// cycle detection at the end of the TU.
  DelegatingCtorDeclsType DelegatingCtorDecls;

  /// \brief All the overriding destructors seen during a class definition
  /// (there could be multiple due to nested classes) that had their exception
  /// spec checks delayed, plus the overridden destructor.
  SmallVector<std::pair<const CXXDestructorDecl*,
                              const CXXDestructorDecl*>, 2>
      DelayedDestructorExceptionSpecChecks;

  /// \brief Callback to the parser to parse templated functions when needed.
  typedef void LateTemplateParserCB(void *P, const FunctionDecl *FD);
  LateTemplateParserCB *LateTemplateParser;
  void *OpaqueParser;

  void SetLateTemplateParser(LateTemplateParserCB *LTP, void *P) {
    LateTemplateParser = LTP;
    OpaqueParser = P;
  }

  class DelayedDiagnostics;

  class ParsingDeclState {
    unsigned SavedStackSize;
    friend class Sema::DelayedDiagnostics;
  };

  class ProcessingContextState {
    unsigned SavedParsingDepth;
    unsigned SavedActiveStackBase;
    friend class Sema::DelayedDiagnostics;
  };

  /// A class which encapsulates the logic for delaying diagnostics
  /// during parsing and other processing.
  class DelayedDiagnostics {
    /// \brief The stack of diagnostics that were delayed due to being
    /// produced during the parsing of a declaration.
    sema::DelayedDiagnostic *Stack;

    /// \brief The number of objects on the delayed-diagnostics stack.
    unsigned StackSize;

    /// \brief The current capacity of the delayed-diagnostics stack.
    unsigned StackCapacity;

    /// \brief The index of the first "active" delayed diagnostic in
    /// the stack.  When parsing class definitions, we ignore active
    /// delayed diagnostics from the surrounding context.
    unsigned ActiveStackBase;

    /// \brief The depth of the declarations we're currently parsing.
    /// This gets saved and reset whenever we enter a class definition.
    unsigned ParsingDepth;

  public:
    DelayedDiagnostics() : Stack(0), StackSize(0), StackCapacity(0),
      ActiveStackBase(0), ParsingDepth(0) {}

    ~DelayedDiagnostics() {
      delete[] reinterpret_cast<char*>(Stack);
    }

    /// Adds a delayed diagnostic.
    void add(const sema::DelayedDiagnostic &diag);

    /// Determines whether diagnostics should be delayed.
    bool shouldDelayDiagnostics() { return ParsingDepth > 0; }

    /// Observe that we've started parsing a declaration.  Access and
    /// deprecation diagnostics will be delayed; when the declaration
    /// is completed, all active delayed diagnostics will be evaluated
    /// in its context, and then active diagnostics stack will be
    /// popped down to the saved depth.
    ParsingDeclState pushParsingDecl() {
      ParsingDepth++;

      ParsingDeclState state;
      state.SavedStackSize = StackSize;
      return state;
    }

    /// Observe that we're completed parsing a declaration.
    static void popParsingDecl(Sema &S, ParsingDeclState state, Decl *decl);

    /// Observe that we've started processing a different context, the
    /// contents of which are semantically separate from the
    /// declarations it may lexically appear in.  This sets aside the
    /// current stack of active diagnostics and starts afresh.
    ProcessingContextState pushContext() {
      assert(StackSize >= ActiveStackBase);

      ProcessingContextState state;
      state.SavedParsingDepth = ParsingDepth;
      state.SavedActiveStackBase = ActiveStackBase;

      ActiveStackBase = StackSize;
      ParsingDepth = 0;

      return state;
    }

    /// Observe that we've stopped processing a context.  This
    /// restores the previous stack of active diagnostics.
    void popContext(ProcessingContextState state) {
      assert(ActiveStackBase == StackSize);
      assert(ParsingDepth == 0);
      ActiveStackBase = state.SavedActiveStackBase;
      ParsingDepth = state.SavedParsingDepth;
    }
  } DelayedDiagnostics;

  /// A RAII object to temporarily push a declaration context.
  class ContextRAII {
  private:
    Sema &S;
    DeclContext *SavedContext;
    ProcessingContextState SavedContextState;
    QualType SavedCXXThisTypeOverride;

  public:
    ContextRAII(Sema &S, DeclContext *ContextToPush)
      : S(S), SavedContext(S.CurContext),
        SavedContextState(S.DelayedDiagnostics.pushContext()),
        SavedCXXThisTypeOverride(S.CXXThisTypeOverride)
    {
      assert(ContextToPush && "pushing null context");
      S.CurContext = ContextToPush;
    }

    void pop() {
      if (!SavedContext) return;
      S.CurContext = SavedContext;
      S.DelayedDiagnostics.popContext(SavedContextState);
      S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
      SavedContext = 0;
    }

    ~ContextRAII() {
      pop();
    }
  };

  /// WeakUndeclaredIdentifiers - Identifiers contained in
  /// #pragma weak before declared. rare. may alias another
  /// identifier, declared or undeclared
  llvm::DenseMap<IdentifierInfo*,WeakInfo> WeakUndeclaredIdentifiers;

  /// ExtnameUndeclaredIdentifiers - Identifiers contained in
  /// #pragma redefine_extname before declared.  Used in Solaris system headers
  /// to define functions that occur in multiple standards to call the version
  /// in the currently selected standard.
  llvm::DenseMap<IdentifierInfo*,AsmLabelAttr*> ExtnameUndeclaredIdentifiers;


  /// \brief Load weak undeclared identifiers from the external source.
  void LoadExternalWeakUndeclaredIdentifiers();

  /// WeakTopLevelDecl - Translation-unit scoped declarations generated by
  /// #pragma weak during processing of other Decls.
  /// I couldn't figure out a clean way to generate these in-line, so
  /// we store them here and handle separately -- which is a hack.
  /// It would be best to refactor this.
  SmallVector<Decl*,2> WeakTopLevelDecl;

  IdentifierResolver IdResolver;

  /// Translation Unit Scope - useful to Objective-C actions that need
  /// to lookup file scope declarations in the "ordinary" C decl namespace.
  /// For example, user-defined classes, built-in "id" type, etc.
  Scope *TUScope;

  /// \brief The C++ "std" namespace, where the standard library resides.
  LazyDeclPtr StdNamespace;

  /// \brief The C++ "std::bad_alloc" class, which is defined by the C++
  /// standard library.
  LazyDeclPtr StdBadAlloc;

  /// \brief The C++ "std::initializer_list" template, which is defined in
  /// <initializer_list>.
  ClassTemplateDecl *StdInitializerList;

  /// \brief The C++ "type_info" declaration, which is defined in <typeinfo>.
  RecordDecl *CXXTypeInfoDecl;

  /// \brief The MSVC "_GUID" struct, which is defined in MSVC header files.
  RecordDecl *MSVCGuidDecl;

  /// \brief Caches identifiers/selectors for NSFoundation APIs.
  llvm::OwningPtr<NSAPI> NSAPIObj;

  /// \brief The declaration of the Objective-C NSNumber class.
  ObjCInterfaceDecl *NSNumberDecl;

  /// \brief Pointer to NSNumber type (NSNumber *).
  QualType NSNumberPointer;

  /// \brief The Objective-C NSNumber methods used to create NSNumber literals.
  ObjCMethodDecl *NSNumberLiteralMethods[NSAPI::NumNSNumberLiteralMethods];

  /// \brief The declaration of the Objective-C NSString class.
  ObjCInterfaceDecl *NSStringDecl;

  /// \brief Pointer to NSString type (NSString *).
  QualType NSStringPointer;

  /// \brief The declaration of the stringWithUTF8String: method.
  ObjCMethodDecl *StringWithUTF8StringMethod;

  /// \brief The declaration of the Objective-C NSArray class.
  ObjCInterfaceDecl *NSArrayDecl;

  /// \brief The declaration of the arrayWithObjects:count: method.
  ObjCMethodDecl *ArrayWithObjectsMethod;

  /// \brief The declaration of the Objective-C NSDictionary class.
  ObjCInterfaceDecl *NSDictionaryDecl;

  /// \brief The declaration of the dictionaryWithObjects:forKeys:count: method.
  ObjCMethodDecl *DictionaryWithObjectsMethod;

  /// \brief id<NSCopying> type.
  QualType QIDNSCopying;

  /// A flag to remember whether the implicit forms of operator new and delete
  /// have been declared.
  bool GlobalNewDeleteDeclared;

  /// A flag that is set when parsing a -dealloc method and no [super dealloc]
  /// call was found yet.
  bool ObjCShouldCallSuperDealloc;
  /// A flag that is set when parsing a -finalize method and no [super finalize]
  /// call was found yet.
  bool ObjCShouldCallSuperFinalize;

  /// \brief Describes how the expressions currently being parsed are
  /// evaluated at run-time, if at all.
  enum ExpressionEvaluationContext {
    /// \brief The current expression and its subexpressions occur within an
    /// unevaluated operand (C++11 [expr]p7), such as the subexpression of
    /// \c sizeof, where the type of the expression may be significant but
    /// no code will be generated to evaluate the value of the expression at
    /// run time.
    Unevaluated,

    /// \brief The current context is "potentially evaluated" in C++11 terms,
    /// but the expression is evaluated at compile-time (like the values of
    /// cases in a switch statment).
    ConstantEvaluated,

    /// \brief The current expression is potentially evaluated at run time,
    /// which means that code may be generated to evaluate the value of the
    /// expression at run time.
    PotentiallyEvaluated,

    /// \brief The current expression is potentially evaluated, but any
    /// declarations referenced inside that expression are only used if
    /// in fact the current expression is used.
    ///
    /// This value is used when parsing default function arguments, for which
    /// we would like to provide diagnostics (e.g., passing non-POD arguments
    /// through varargs) but do not want to mark declarations as "referenced"
    /// until the default argument is used.
    PotentiallyEvaluatedIfUsed
  };

  /// \brief Data structure used to record current or nested
  /// expression evaluation contexts.
  struct ExpressionEvaluationContextRecord {
    /// \brief The expression evaluation context.
    ExpressionEvaluationContext Context;

    /// \brief Whether the enclosing context needed a cleanup.
    bool ParentNeedsCleanups;

    /// \brief Whether we are in a decltype expression.
    bool IsDecltype;

    /// \brief The number of active cleanup objects when we entered
    /// this expression evaluation context.
    unsigned NumCleanupObjects;

    llvm::SmallPtrSet<Expr*, 8> SavedMaybeODRUseExprs;

    /// \brief The lambdas that are present within this context, if it
    /// is indeed an unevaluated context.
    llvm::SmallVector<LambdaExpr *, 2> Lambdas;

    /// \brief The declaration that provides context for the lambda expression
    /// if the normal declaration context does not suffice, e.g., in a
    /// default function argument.
    Decl *LambdaContextDecl;

    /// \brief The context information used to mangle lambda expressions
    /// within this context.
    ///
    /// This mangling information is allocated lazily, since most contexts
    /// do not have lambda expressions.
    LambdaMangleContext *LambdaMangle;

    /// \brief If we are processing a decltype type, a set of call expressions
    /// for which we have deferred checking the completeness of the return type.
    llvm::SmallVector<CallExpr*, 8> DelayedDecltypeCalls;

    /// \brief If we are processing a decltype type, a set of temporary binding
    /// expressions for which we have deferred checking the destructor.
    llvm::SmallVector<CXXBindTemporaryExpr*, 8> DelayedDecltypeBinds;

    ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
                                      unsigned NumCleanupObjects,
                                      bool ParentNeedsCleanups,
                                      Decl *LambdaContextDecl,
                                      bool IsDecltype)
      : Context(Context), ParentNeedsCleanups(ParentNeedsCleanups),
        IsDecltype(IsDecltype), NumCleanupObjects(NumCleanupObjects),
        LambdaContextDecl(LambdaContextDecl), LambdaMangle() { }

    ~ExpressionEvaluationContextRecord() {
      delete LambdaMangle;
    }

    /// \brief Retrieve the mangling context for lambdas.
    LambdaMangleContext &getLambdaMangleContext() {
      assert(LambdaContextDecl && "Need to have a lambda context declaration");
      if (!LambdaMangle)
        LambdaMangle = new LambdaMangleContext;
      return *LambdaMangle;
    }
  };

  /// A stack of expression evaluation contexts.
  SmallVector<ExpressionEvaluationContextRecord, 8> ExprEvalContexts;

  /// SpecialMemberOverloadResult - The overloading result for a special member
  /// function.
  ///
  /// This is basically a wrapper around PointerIntPair. The lowest bit of the
  /// integer is used to determine whether we have a parameter qualification
  /// match, the second-lowest is whether we had success in resolving the
  /// overload to a unique non-deleted function.
  ///
  /// The ConstParamMatch bit represents whether, when looking up a copy
  /// constructor or assignment operator, we found a potential copy
  /// constructor/assignment operator whose first parameter is const-qualified.
  /// This is used for determining parameter types of other objects and is
  /// utterly meaningless on other types of special members.
  class SpecialMemberOverloadResult : public llvm::FastFoldingSetNode {
  public:
    enum Kind {
      NoMemberOrDeleted,
      Ambiguous,
      SuccessNonConst,
      SuccessConst
    };

  private:
    llvm::PointerIntPair<CXXMethodDecl*, 2> Pair;

  public:
    SpecialMemberOverloadResult(const llvm::FoldingSetNodeID &ID)
      : FastFoldingSetNode(ID)
    {}

    CXXMethodDecl *getMethod() const { return Pair.getPointer(); }
    void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }

    Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
    void setKind(Kind K) { Pair.setInt(K); }

    bool hasSuccess() const { return getKind() >= SuccessNonConst; }
    bool hasConstParamMatch() const { return getKind() == SuccessConst; }
  };

  /// \brief A cache of special member function overload resolution results
  /// for C++ records.
  llvm::FoldingSet<SpecialMemberOverloadResult> SpecialMemberCache;

  /// \brief The kind of translation unit we are processing.
  ///
  /// When we're processing a complete translation unit, Sema will perform
  /// end-of-translation-unit semantic tasks (such as creating
  /// initializers for tentative definitions in C) once parsing has
  /// completed. Modules and precompiled headers perform different kinds of
  /// checks.
  TranslationUnitKind TUKind;

  llvm::BumpPtrAllocator BumpAlloc;

  /// \brief The number of SFINAE diagnostics that have been trapped.
  unsigned NumSFINAEErrors;

  typedef llvm::DenseMap<ParmVarDecl *, SmallVector<ParmVarDecl *, 1> >
    UnparsedDefaultArgInstantiationsMap;

  /// \brief A mapping from parameters with unparsed default arguments to the
  /// set of instantiations of each parameter.
  ///
  /// This mapping is a temporary data structure used when parsing
  /// nested class templates or nested classes of class templates,
  /// where we might end up instantiating an inner class before the
  /// default arguments of its methods have been parsed.
  UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;

  // Contains the locations of the beginning of unparsed default
  // argument locations.
  llvm::DenseMap<ParmVarDecl *,SourceLocation> UnparsedDefaultArgLocs;

  /// UndefinedInternals - all the used, undefined objects with
  /// internal linkage in this translation unit.
  llvm::DenseMap<NamedDecl*, SourceLocation> UndefinedInternals;

  typedef std::pair<ObjCMethodList, ObjCMethodList> GlobalMethods;
  typedef llvm::DenseMap<Selector, GlobalMethods> GlobalMethodPool;

  /// Method Pool - allows efficient lookup when typechecking messages to "id".
  /// We need to maintain a list, since selectors can have differing signatures
  /// across classes. In Cocoa, this happens to be extremely uncommon (only 1%
  /// of selectors are "overloaded").
  GlobalMethodPool MethodPool;

  /// Method selectors used in a @selector expression. Used for implementation
  /// of -Wselector.
  llvm::DenseMap<Selector, SourceLocation> ReferencedSelectors;

  void ReadMethodPool(Selector Sel);

  /// Private Helper predicate to check for 'self'.
  bool isSelfExpr(Expr *RExpr);

  /// \brief Cause the active diagnostic on the DiagosticsEngine to be
  /// emitted. This is closely coupled to the SemaDiagnosticBuilder class and
  /// should not be used elsewhere.
  void EmitCurrentDiagnostic(unsigned DiagID);

public:
  Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
       TranslationUnitKind TUKind = TU_Complete,
       CodeCompleteConsumer *CompletionConsumer = 0);
  ~Sema();

  /// \brief Perform initialization that occurs after the parser has been
  /// initialized but before it parses anything.
  void Initialize();

  const LangOptions &getLangOpts() const { return LangOpts; }
  OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
  FPOptions     &getFPOptions() { return FPFeatures; }

  DiagnosticsEngine &getDiagnostics() const { return Diags; }
  SourceManager &getSourceManager() const { return SourceMgr; }
  const TargetAttributesSema &getTargetAttributesSema() const;
  Preprocessor &getPreprocessor() const { return PP; }
  ASTContext &getASTContext() const { return Context; }
  ASTConsumer &getASTConsumer() const { return Consumer; }
  ASTMutationListener *getASTMutationListener() const;

  void PrintStats() const;

  /// \brief Helper class that creates diagnostics with optional
  /// template instantiation stacks.
  ///
  /// This class provides a wrapper around the basic DiagnosticBuilder
  /// class that emits diagnostics. SemaDiagnosticBuilder is
  /// responsible for emitting the diagnostic (as DiagnosticBuilder
  /// does) and, if the diagnostic comes from inside a template
  /// instantiation, printing the template instantiation stack as
  /// well.
  class SemaDiagnosticBuilder : public DiagnosticBuilder {
    Sema &SemaRef;
    unsigned DiagID;

  public:
    SemaDiagnosticBuilder(DiagnosticBuilder &DB, Sema &SemaRef, unsigned DiagID)
      : DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) { }

    ~SemaDiagnosticBuilder() {
      // If we aren't active, there is nothing to do.
      if (!isActive()) return;

      // Otherwise, we need to emit the diagnostic. First flush the underlying
      // DiagnosticBuilder data, and clear the diagnostic builder itself so it
      // won't emit the diagnostic in its own destructor.
      //
      // This seems wasteful, in that as written the DiagnosticBuilder dtor will
      // do its own needless checks to see if the diagnostic needs to be
      // emitted. However, because we take care to ensure that the builder
      // objects never escape, a sufficiently smart compiler will be able to
      // eliminate that code.
      FlushCounts();
      Clear();

      // Dispatch to Sema to emit the diagnostic.
      SemaRef.EmitCurrentDiagnostic(DiagID);
    }
  };

  /// \brief Emit a diagnostic.
  SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID) {
    DiagnosticBuilder DB = Diags.Report(Loc, DiagID);
    return SemaDiagnosticBuilder(DB, *this, DiagID);
  }

  /// \brief Emit a partial diagnostic.
  SemaDiagnosticBuilder Diag(SourceLocation Loc, const PartialDiagnostic& PD);

  /// \brief Build a partial diagnostic.
  PartialDiagnostic PDiag(unsigned DiagID = 0); // in SemaInternal.h

  bool findMacroSpelling(SourceLocation &loc, StringRef name);

  /// \brief Get a string to suggest for zero-initialization of a type.
  const char *getFixItZeroInitializerForType(QualType T) const;

  ExprResult Owned(Expr* E) { return E; }
  ExprResult Owned(ExprResult R) { return R; }
  StmtResult Owned(Stmt* S) { return S; }

  void ActOnEndOfTranslationUnit();

  void CheckDelegatingCtorCycles();

  Scope *getScopeForContext(DeclContext *Ctx);

  void PushFunctionScope();
  void PushBlockScope(Scope *BlockScope, BlockDecl *Block);
  void PushLambdaScope(CXXRecordDecl *Lambda, CXXMethodDecl *CallOperator);
  void PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy *WP =0,
                            const Decl *D = 0, const BlockExpr *blkExpr = 0);

  sema::FunctionScopeInfo *getCurFunction() const {
    return FunctionScopes.back();
  }

  void PushCompoundScope();
  void PopCompoundScope();

  sema::CompoundScopeInfo &getCurCompoundScope() const;

  bool hasAnyUnrecoverableErrorsInThisFunction() const;

  /// \brief Retrieve the current block, if any.
  sema::BlockScopeInfo *getCurBlock();

  /// \brief Retrieve the current lambda expression, if any.
  sema::LambdaScopeInfo *getCurLambda();

  /// WeakTopLevelDeclDecls - access to #pragma weak-generated Decls
  SmallVector<Decl*,2> &WeakTopLevelDecls() { return WeakTopLevelDecl; }

  //===--------------------------------------------------------------------===//
  // Type Analysis / Processing: SemaType.cpp.
  //

  QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs);
  QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVR) {
    return BuildQualifiedType(T, Loc, Qualifiers::fromCVRMask(CVR));
  }
  QualType BuildPointerType(QualType T,
                            SourceLocation Loc, DeclarationName Entity);
  QualType BuildReferenceType(QualType T, bool LValueRef,
                              SourceLocation Loc, DeclarationName Entity);
  QualType BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
                          Expr *ArraySize, unsigned Quals,
                          SourceRange Brackets, DeclarationName Entity);
  QualType BuildExtVectorType(QualType T, Expr *ArraySize,
                              SourceLocation AttrLoc);
  QualType BuildFunctionType(QualType T,
                             QualType *ParamTypes, unsigned NumParamTypes,
                             bool Variadic, bool HasTrailingReturn,
                             unsigned Quals, RefQualifierKind RefQualifier,
                             SourceLocation Loc, DeclarationName Entity,
                             FunctionType::ExtInfo Info);
  QualType BuildMemberPointerType(QualType T, QualType Class,
                                  SourceLocation Loc,
                                  DeclarationName Entity);
  QualType BuildBlockPointerType(QualType T,
                                 SourceLocation Loc, DeclarationName Entity);
  QualType BuildParenType(QualType T);
  QualType BuildAtomicType(QualType T, SourceLocation Loc);

  TypeSourceInfo *GetTypeForDeclarator(Declarator &D, Scope *S);
  TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);
  TypeSourceInfo *GetTypeSourceInfoForDeclarator(Declarator &D, QualType T,
                                               TypeSourceInfo *ReturnTypeInfo);

  /// \brief Package the given type and TSI into a ParsedType.
  ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
  DeclarationNameInfo GetNameForDeclarator(Declarator &D);
  DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
  static QualType GetTypeFromParser(ParsedType Ty, TypeSourceInfo **TInfo = 0);
  CanThrowResult canThrow(const Expr *E);
  const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
                                                const FunctionProtoType *FPT);
  bool CheckSpecifiedExceptionType(QualType T, const SourceRange &Range);
  bool CheckDistantExceptionSpec(QualType T);
  bool CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New);
  bool CheckEquivalentExceptionSpec(
      const FunctionProtoType *Old, SourceLocation OldLoc,
      const FunctionProtoType *New, SourceLocation NewLoc);
  bool CheckEquivalentExceptionSpec(
      const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
      const FunctionProtoType *Old, SourceLocation OldLoc,
      const FunctionProtoType *New, SourceLocation NewLoc,
      bool *MissingExceptionSpecification = 0,
      bool *MissingEmptyExceptionSpecification = 0,
      bool AllowNoexceptAllMatchWithNoSpec = false,
      bool IsOperatorNew = false);
  bool CheckExceptionSpecSubset(
      const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
      const FunctionProtoType *Superset, SourceLocation SuperLoc,
      const FunctionProtoType *Subset, SourceLocation SubLoc);
  bool CheckParamExceptionSpec(const PartialDiagnostic & NoteID,
      const FunctionProtoType *Target, SourceLocation TargetLoc,
      const FunctionProtoType *Source, SourceLocation SourceLoc);

  TypeResult ActOnTypeName(Scope *S, Declarator &D);

  /// \brief The parser has parsed the context-sensitive type 'instancetype'
  /// in an Objective-C message declaration. Return the appropriate type.
  ParsedType ActOnObjCInstanceType(SourceLocation Loc);

  bool RequireCompleteType(SourceLocation Loc, QualType T,
                           const PartialDiagnostic &PD,
                           std::pair<SourceLocation, PartialDiagnostic> Note);
  bool RequireCompleteType(SourceLocation Loc, QualType T,
                           const PartialDiagnostic &PD);
  bool RequireCompleteType(SourceLocation Loc, QualType T,
                           unsigned DiagID);
  bool RequireCompleteExprType(Expr *E, const PartialDiagnostic &PD,
                               std::pair<SourceLocation,
                                         PartialDiagnostic> Note);

  bool RequireLiteralType(SourceLocation Loc, QualType T,
                          const PartialDiagnostic &PD);

  QualType getElaboratedType(ElaboratedTypeKeyword Keyword,
                             const CXXScopeSpec &SS, QualType T);

  QualType BuildTypeofExprType(Expr *E, SourceLocation Loc);
  QualType BuildDecltypeType(Expr *E, SourceLocation Loc);
  QualType BuildUnaryTransformType(QualType BaseType,
                                   UnaryTransformType::UTTKind UKind,
                                   SourceLocation Loc);

  //===--------------------------------------------------------------------===//
  // Symbol table / Decl tracking callbacks: SemaDecl.cpp.
  //

  /// List of decls defined in a function prototype. This contains EnumConstants
  /// that incorrectly end up in translation unit scope because there is no
  /// function to pin them on. ActOnFunctionDeclarator reads this list and patches
  /// them into the FunctionDecl.
  std::vector<NamedDecl*> DeclsInPrototypeScope;
  /// Nonzero if we are currently parsing a function declarator. This is a counter
  /// as opposed to a boolean so we can deal with nested function declarators
  /// such as:
  ///     void f(void (*g)(), ...)
  unsigned InFunctionDeclarator;

  DeclGroupPtrTy ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType = 0);

  void DiagnoseUseOfUnimplementedSelectors();

  ParsedType getTypeName(IdentifierInfo &II, SourceLocation NameLoc,
                         Scope *S, CXXScopeSpec *SS = 0,
                         bool isClassName = false,
                         bool HasTrailingDot = false,
                         ParsedType ObjectType = ParsedType(),
                         bool IsCtorOrDtorName = false,
                         bool WantNontrivialTypeSourceInfo = false,
                         IdentifierInfo **CorrectedII = 0);
  TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
  bool isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S);
  bool DiagnoseUnknownTypeName(const IdentifierInfo &II,
                               SourceLocation IILoc,
                               Scope *S,
                               CXXScopeSpec *SS,
                               ParsedType &SuggestedType);

  /// \brief Describes the result of the name lookup and resolution performed
  /// by \c ClassifyName().
  enum NameClassificationKind {
    NC_Unknown,
    NC_Error,
    NC_Keyword,
    NC_Type,
    NC_Expression,
    NC_NestedNameSpecifier,
    NC_TypeTemplate,
    NC_FunctionTemplate
  };

  class NameClassification {
    NameClassificationKind Kind;
    ExprResult Expr;
    TemplateName Template;
    ParsedType Type;
    const IdentifierInfo *Keyword;

    explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}

  public:
    NameClassification(ExprResult Expr) : Kind(NC_Expression), Expr(Expr) {}

    NameClassification(ParsedType Type) : Kind(NC_Type), Type(Type) {}

    NameClassification(const IdentifierInfo *Keyword)
      : Kind(NC_Keyword), Keyword(Keyword) { }

    static NameClassification Error() {
      return NameClassification(NC_Error);
    }

    static NameClassification Unknown() {
      return NameClassification(NC_Unknown);
    }

    static NameClassification NestedNameSpecifier() {
      return NameClassification(NC_NestedNameSpecifier);
    }

    static NameClassification TypeTemplate(TemplateName Name) {
      NameClassification Result(NC_TypeTemplate);
      Result.Template = Name;
      return Result;
    }

    static NameClassification FunctionTemplate(TemplateName Name) {
      NameClassification Result(NC_FunctionTemplate);
      Result.Template = Name;
      return Result;
    }

    NameClassificationKind getKind() const { return Kind; }

    ParsedType getType() const {
      assert(Kind == NC_Type);
      return Type;
    }

    ExprResult getExpression() const {
      assert(Kind == NC_Expression);
      return Expr;
    }

    TemplateName getTemplateName() const {
      assert(Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate);
      return Template;
    }

    TemplateNameKind getTemplateNameKind() const {
      assert(Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate);
      return Kind == NC_TypeTemplate? TNK_Type_template : TNK_Function_template;
    }
};

  /// \brief Perform name lookup on the given name, classifying it based on
  /// the results of name lookup and the following token.
  ///
  /// This routine is used by the parser to resolve identifiers and help direct
  /// parsing. When the identifier cannot be found, this routine will attempt
  /// to correct the typo and classify based on the resulting name.
  ///
  /// \param S The scope in which we're performing name lookup.
  ///
  /// \param SS The nested-name-specifier that precedes the name.
  ///
  /// \param Name The identifier. If typo correction finds an alternative name,
  /// this pointer parameter will be updated accordingly.
  ///
  /// \param NameLoc The location of the identifier.
  ///
  /// \param NextToken The token following the identifier. Used to help
  /// disambiguate the name.
  NameClassification ClassifyName(Scope *S,
                                  CXXScopeSpec &SS,
                                  IdentifierInfo *&Name,
                                  SourceLocation NameLoc,
                                  const Token &NextToken);

  Decl *ActOnDeclarator(Scope *S, Declarator &D);

  Decl *HandleDeclarator(Scope *S, Declarator &D,
                         MultiTemplateParamsArg TemplateParameterLists);
  void RegisterLocallyScopedExternCDecl(NamedDecl *ND,
                                        const LookupResult &Previous,
                                        Scope *S);
  bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
  bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
                                    DeclarationName Name,
                                    SourceLocation Loc);
  void DiagnoseFunctionSpecifiers(Declarator& D);
  void CheckShadow(Scope *S, VarDecl *D, const LookupResult& R);
  void CheckShadow(Scope *S, VarDecl *D);
  void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
  void CheckTypedefForVariablyModifiedType(Scope *S, TypedefNameDecl *D);
  NamedDecl* ActOnTypedefDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                    TypeSourceInfo *TInfo,
                                    LookupResult &Previous);
  NamedDecl* ActOnTypedefNameDecl(Scope* S, DeclContext* DC, TypedefNameDecl *D,
                                  LookupResult &Previous, bool &Redeclaration);
  NamedDecl* ActOnVariableDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                     TypeSourceInfo *TInfo,
                                     LookupResult &Previous,
                                     MultiTemplateParamsArg TemplateParamLists);
  // Returns true if the variable declaration is a redeclaration
  bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
  void CheckCompleteVariableDeclaration(VarDecl *var);
  void ActOnStartFunctionDeclarator();
  void ActOnEndFunctionDeclarator();
  NamedDecl* ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
                                     TypeSourceInfo *TInfo,
                                     LookupResult &Previous,
                                     MultiTemplateParamsArg TemplateParamLists,
                                     bool &AddToScope);
  bool AddOverriddenMethods(CXXRecordDecl *DC, CXXMethodDecl *MD);

  bool CheckConstexprFunctionDecl(const FunctionDecl *FD);
  bool CheckConstexprFunctionBody(const FunctionDecl *FD, Stmt *Body);

  void DiagnoseHiddenVirtualMethods(CXXRecordDecl *DC, CXXMethodDecl *MD);
  // Returns true if the function declaration is a redeclaration
  bool CheckFunctionDeclaration(Scope *S,
                                FunctionDecl *NewFD, LookupResult &Previous,
                                bool IsExplicitSpecialization);
  void CheckMain(FunctionDecl *FD, const DeclSpec &D);
  Decl *ActOnParamDeclarator(Scope *S, Declarator &D);
  ParmVarDecl *BuildParmVarDeclForTypedef(DeclContext *DC,
                                          SourceLocation Loc,
                                          QualType T);
  ParmVarDecl *CheckParameter(DeclContext *DC, SourceLocation StartLoc,
                              SourceLocation NameLoc, IdentifierInfo *Name,
                              QualType T, TypeSourceInfo *TSInfo,
                              StorageClass SC, StorageClass SCAsWritten);
  void ActOnParamDefaultArgument(Decl *param,
                                 SourceLocation EqualLoc,
                                 Expr *defarg);
  void ActOnParamUnparsedDefaultArgument(Decl *param,
                                         SourceLocation EqualLoc,
                                         SourceLocation ArgLoc);
  void ActOnParamDefaultArgumentError(Decl *param);
  bool SetParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                               SourceLocation EqualLoc);

  void CheckSelfReference(Decl *OrigDecl, Expr *E);
  void AddInitializerToDecl(Decl *dcl, Expr *init, bool DirectInit,
                            bool TypeMayContainAuto);
  void ActOnUninitializedDecl(Decl *dcl, bool TypeMayContainAuto);
  void ActOnInitializerError(Decl *Dcl);
  void ActOnCXXForRangeDecl(Decl *D);
  void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc);
  void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
  void FinalizeDeclaration(Decl *D);
  DeclGroupPtrTy FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
                                         Decl **Group,
                                         unsigned NumDecls);
  DeclGroupPtrTy BuildDeclaratorGroup(Decl **Group, unsigned NumDecls,
                                      bool TypeMayContainAuto = true);
  void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
                                       SourceLocation LocAfterDecls);
  void CheckForFunctionRedefinition(FunctionDecl *FD);
  Decl *ActOnStartOfFunctionDef(Scope *S, Declarator &D);
  Decl *ActOnStartOfFunctionDef(Scope *S, Decl *D);
  void ActOnStartOfObjCMethodDef(Scope *S, Decl *D);

  void computeNRVO(Stmt *Body, sema::FunctionScopeInfo *Scope);
  Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body);
  Decl *ActOnFinishFunctionBody(Decl *Decl, Stmt *Body, bool IsInstantiation);

  /// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
  /// attribute for which parsing is delayed.
  void ActOnFinishDelayedAttribute(Scope *S, Decl *D, ParsedAttributes &Attrs);

  /// \brief Diagnose any unused parameters in the given sequence of
  /// ParmVarDecl pointers.
  void DiagnoseUnusedParameters(ParmVarDecl * const *Begin,
                                ParmVarDecl * const *End);

  /// \brief Diagnose whether the size of parameters or return value of a
  /// function or obj-c method definition is pass-by-value and larger than a
  /// specified threshold.
  void DiagnoseSizeOfParametersAndReturnValue(ParmVarDecl * const *Begin,
                                              ParmVarDecl * const *End,
                                              QualType ReturnTy,
                                              NamedDecl *D);

  void DiagnoseInvalidJumps(Stmt *Body);
  Decl *ActOnFileScopeAsmDecl(Expr *expr,
                              SourceLocation AsmLoc,
                              SourceLocation RParenLoc);

  /// \brief The parser has processed a module import declaration.
  ///
  /// \param AtLoc The location of the '@' symbol, if any.
  ///
  /// \param ImportLoc The location of the 'import' keyword.
  ///
  /// \param Path The module access path.
  DeclResult ActOnModuleImport(SourceLocation AtLoc, SourceLocation ImportLoc,
                               ModuleIdPath Path);

  /// \brief Retrieve a suitable printing policy.
  PrintingPolicy getPrintingPolicy() const {
    return getPrintingPolicy(Context, PP);
  }

  /// \brief Retrieve a suitable printing policy.
  static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
                                          const Preprocessor &PP);

  /// Scope actions.
  void ActOnPopScope(SourceLocation Loc, Scope *S);
  void ActOnTranslationUnitScope(Scope *S);

  Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
                                   DeclSpec &DS);
  Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
                                   DeclSpec &DS,
                                   MultiTemplateParamsArg TemplateParams);

  Decl *BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
                                    AccessSpecifier AS,
                                    RecordDecl *Record);

  Decl *BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
                                       RecordDecl *Record);

  bool isAcceptableTagRedeclaration(const TagDecl *Previous,
                                    TagTypeKind NewTag, bool isDefinition,
                                    SourceLocation NewTagLoc,
                                    const IdentifierInfo &Name);

  enum TagUseKind {
    TUK_Reference,   // Reference to a tag:  'struct foo *X;'
    TUK_Declaration, // Fwd decl of a tag:   'struct foo;'
    TUK_Definition,  // Definition of a tag: 'struct foo { int X; } Y;'
    TUK_Friend       // Friend declaration:  'friend struct foo;'
  };

  Decl *ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                 SourceLocation KWLoc, CXXScopeSpec &SS,
                 IdentifierInfo *Name, SourceLocation NameLoc,
                 AttributeList *Attr, AccessSpecifier AS,
                 SourceLocation ModulePrivateLoc,
                 MultiTemplateParamsArg TemplateParameterLists,
                 bool &OwnedDecl, bool &IsDependent,
                 SourceLocation ScopedEnumKWLoc,
                 bool ScopedEnumUsesClassTag, TypeResult UnderlyingType);

  Decl *ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                                unsigned TagSpec, SourceLocation TagLoc,
                                CXXScopeSpec &SS,
                                IdentifierInfo *Name, SourceLocation NameLoc,
                                AttributeList *Attr,
                                MultiTemplateParamsArg TempParamLists);

  TypeResult ActOnDependentTag(Scope *S,
                               unsigned TagSpec,
                               TagUseKind TUK,
                               const CXXScopeSpec &SS,
                               IdentifierInfo *Name,
                               SourceLocation TagLoc,
                               SourceLocation NameLoc);

  void ActOnDefs(Scope *S, Decl *TagD, SourceLocation DeclStart,
                 IdentifierInfo *ClassName,
                 SmallVectorImpl<Decl *> &Decls);
  Decl *ActOnField(Scope *S, Decl *TagD, SourceLocation DeclStart,
                   Declarator &D, Expr *BitfieldWidth);

  FieldDecl *HandleField(Scope *S, RecordDecl *TagD, SourceLocation DeclStart,
                         Declarator &D, Expr *BitfieldWidth, bool HasInit,
                         AccessSpecifier AS);

  FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
                            TypeSourceInfo *TInfo,
                            RecordDecl *Record, SourceLocation Loc,
                            bool Mutable, Expr *BitfieldWidth, bool HasInit,
                            SourceLocation TSSL,
                            AccessSpecifier AS, NamedDecl *PrevDecl,
                            Declarator *D = 0);

  enum CXXSpecialMember {
    CXXDefaultConstructor,
    CXXCopyConstructor,
    CXXMoveConstructor,
    CXXCopyAssignment,
    CXXMoveAssignment,
    CXXDestructor,
    CXXInvalid
  };
  bool CheckNontrivialField(FieldDecl *FD);
  void DiagnoseNontrivial(const RecordType* Record, CXXSpecialMember mem);
  CXXSpecialMember getSpecialMember(const CXXMethodDecl *MD);
  void ActOnLastBitfield(SourceLocation DeclStart,
                         SmallVectorImpl<Decl *> &AllIvarDecls);
  Decl *ActOnIvar(Scope *S, SourceLocation DeclStart,
                  Declarator &D, Expr *BitfieldWidth,
                  tok::ObjCKeywordKind visibility);

  // This is used for both record definitions and ObjC interface declarations.
  void ActOnFields(Scope* S, SourceLocation RecLoc, Decl *TagDecl,
                   llvm::ArrayRef<Decl *> Fields,
                   SourceLocation LBrac, SourceLocation RBrac,
                   AttributeList *AttrList);

  /// ActOnTagStartDefinition - Invoked when we have entered the
  /// scope of a tag's definition (e.g., for an enumeration, class,
  /// struct, or union).
  void ActOnTagStartDefinition(Scope *S, Decl *TagDecl);

  Decl *ActOnObjCContainerStartDefinition(Decl *IDecl);

  /// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
  /// C++ record definition's base-specifiers clause and are starting its
  /// member declarations.
  void ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagDecl,
                                       SourceLocation FinalLoc,
                                       SourceLocation LBraceLoc);

  /// ActOnTagFinishDefinition - Invoked once we have finished parsing
  /// the definition of a tag (enumeration, class, struct, or union).
  void ActOnTagFinishDefinition(Scope *S, Decl *TagDecl,
                                SourceLocation RBraceLoc);

  void ActOnObjCContainerFinishDefinition();

  /// \brief Invoked when we must temporarily exit the objective-c container
  /// scope for parsing/looking-up C constructs.
  ///
  /// Must be followed by a call to \see ActOnObjCReenterContainerContext
  void ActOnObjCTemporaryExitContainerContext(DeclContext *DC);
  void ActOnObjCReenterContainerContext(DeclContext *DC);

  /// ActOnTagDefinitionError - Invoked when there was an unrecoverable
  /// error parsing the definition of a tag.
  void ActOnTagDefinitionError(Scope *S, Decl *TagDecl);

  EnumConstantDecl *CheckEnumConstant(EnumDecl *Enum,
                                      EnumConstantDecl *LastEnumConst,
                                      SourceLocation IdLoc,
                                      IdentifierInfo *Id,
                                      Expr *val);
  bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
  bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
                              QualType EnumUnderlyingTy, const EnumDecl *Prev);

  Decl *ActOnEnumConstant(Scope *S, Decl *EnumDecl, Decl *LastEnumConstant,
                          SourceLocation IdLoc, IdentifierInfo *Id,
                          AttributeList *Attrs,
                          SourceLocation EqualLoc, Expr *Val);
  void ActOnEnumBody(SourceLocation EnumLoc, SourceLocation LBraceLoc,
                     SourceLocation RBraceLoc, Decl *EnumDecl,
                     Decl **Elements, unsigned NumElements,
                     Scope *S, AttributeList *Attr);

  DeclContext *getContainingDC(DeclContext *DC);

  /// Set the current declaration context until it gets popped.
  void PushDeclContext(Scope *S, DeclContext *DC);
  void PopDeclContext();

  /// EnterDeclaratorContext - Used when we must lookup names in the context
  /// of a declarator's nested name specifier.
  void EnterDeclaratorContext(Scope *S, DeclContext *DC);
  void ExitDeclaratorContext(Scope *S);

  /// Push the parameters of D, which must be a function, into scope.
  void ActOnReenterFunctionContext(Scope* S, Decl* D);
  void ActOnExitFunctionContext();

  DeclContext *getFunctionLevelDeclContext();

  /// getCurFunctionDecl - If inside of a function body, this returns a pointer
  /// to the function decl for the function being parsed.  If we're currently
  /// in a 'block', this returns the containing context.
  FunctionDecl *getCurFunctionDecl();

  /// getCurMethodDecl - If inside of a method body, this returns a pointer to
  /// the method decl for the method being parsed.  If we're currently
  /// in a 'block', this returns the containing context.
  ObjCMethodDecl *getCurMethodDecl();

  /// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
  /// or C function we're in, otherwise return null.  If we're currently
  /// in a 'block', this returns the containing context.
  NamedDecl *getCurFunctionOrMethodDecl();

  /// Add this decl to the scope shadowed decl chains.
  void PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext = true);

  /// \brief Make the given externally-produced declaration visible at the
  /// top level scope.
  ///
  /// \param D The externally-produced declaration to push.
  ///
  /// \param Name The name of the externally-produced declaration.
  void pushExternalDeclIntoScope(NamedDecl *D, DeclarationName Name);

  /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
  /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
  /// true if 'D' belongs to the given declaration context.
  ///
  /// \param ExplicitInstantiationOrSpecialization When true, we are checking
  /// whether the declaration is in scope for the purposes of explicit template
  /// instantiation or specialization. The default is false.
  bool isDeclInScope(NamedDecl *&D, DeclContext *Ctx, Scope *S = 0,
                     bool ExplicitInstantiationOrSpecialization = false);

  /// Finds the scope corresponding to the given decl context, if it
  /// happens to be an enclosing scope.  Otherwise return NULL.
  static Scope *getScopeForDeclContext(Scope *S, DeclContext *DC);

  /// Subroutines of ActOnDeclarator().
  TypedefDecl *ParseTypedefDecl(Scope *S, Declarator &D, QualType T,
                                TypeSourceInfo *TInfo);
  bool isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New);
  void mergeDeclAttributes(Decl *New, Decl *Old, bool MergeDeprecation = true);
  void MergeTypedefNameDecl(TypedefNameDecl *New, LookupResult &OldDecls);
  bool MergeFunctionDecl(FunctionDecl *New, Decl *Old, Scope *S);
  bool MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
                                    Scope *S);
  void mergeObjCMethodDecls(ObjCMethodDecl *New, ObjCMethodDecl *Old);
  void MergeVarDecl(VarDecl *New, LookupResult &OldDecls);
  void MergeVarDeclTypes(VarDecl *New, VarDecl *Old);
  void MergeVarDeclExceptionSpecs(VarDecl *New, VarDecl *Old);
  bool MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old, Scope *S);

  // AssignmentAction - This is used by all the assignment diagnostic functions
  // to represent what is actually causing the operation
  enum AssignmentAction {
    AA_Assigning,
    AA_Passing,
    AA_Returning,
    AA_Converting,
    AA_Initializing,
    AA_Sending,
    AA_Casting
  };

  /// C++ Overloading.
  enum OverloadKind {
    /// This is a legitimate overload: the existing declarations are
    /// functions or function templates with different signatures.
    Ovl_Overload,

    /// This is not an overload because the signature exactly matches
    /// an existing declaration.
    Ovl_Match,

    /// This is not an overload because the lookup results contain a
    /// non-function.
    Ovl_NonFunction
  };
  OverloadKind CheckOverload(Scope *S,
                             FunctionDecl *New,
                             const LookupResult &OldDecls,
                             NamedDecl *&OldDecl,
                             bool IsForUsingDecl);
  bool IsOverload(FunctionDecl *New, FunctionDecl *Old, bool IsForUsingDecl);

  /// \brief Checks availability of the function depending on the current
  /// function context.Inside an unavailable function,unavailability is ignored.
  ///
  /// \returns true if \arg FD is unavailable and current context is inside
  /// an available function, false otherwise.
  bool isFunctionConsideredUnavailable(FunctionDecl *FD);

  ImplicitConversionSequence
  TryImplicitConversion(Expr *From, QualType ToType,
                        bool SuppressUserConversions,
                        bool AllowExplicit,
                        bool InOverloadResolution,
                        bool CStyle,
                        bool AllowObjCWritebackConversion);

  bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
  bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
  bool IsComplexPromotion(QualType FromType, QualType ToType);
  bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
                           bool InOverloadResolution,
                           QualType& ConvertedType, bool &IncompatibleObjC);
  bool isObjCPointerConversion(QualType FromType, QualType ToType,
                               QualType& ConvertedType, bool &IncompatibleObjC);
  bool isObjCWritebackConversion(QualType FromType, QualType ToType,
                                 QualType &ConvertedType);
  bool IsBlockPointerConversion(QualType FromType, QualType ToType,
                                QualType& ConvertedType);
  bool FunctionArgTypesAreEqual(const FunctionProtoType *OldType,
                                const FunctionProtoType *NewType,
                                unsigned *ArgPos = 0);
  void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
                                  QualType FromType, QualType ToType);

  CastKind PrepareCastToObjCObjectPointer(ExprResult &E);
  bool CheckPointerConversion(Expr *From, QualType ToType,
                              CastKind &Kind,
                              CXXCastPath& BasePath,
                              bool IgnoreBaseAccess);
  bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
                                 bool InOverloadResolution,
                                 QualType &ConvertedType);
  bool CheckMemberPointerConversion(Expr *From, QualType ToType,
                                    CastKind &Kind,
                                    CXXCastPath &BasePath,
                                    bool IgnoreBaseAccess);
  bool IsQualificationConversion(QualType FromType, QualType ToType,
                                 bool CStyle, bool &ObjCLifetimeConversion);
  bool IsNoReturnConversion(QualType FromType, QualType ToType,
                            QualType &ResultTy);
  bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);


  ExprResult PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
                                             const VarDecl *NRVOCandidate,
                                             QualType ResultType,
                                             Expr *Value,
                                             bool AllowNRVO = true);

  bool CanPerformCopyInitialization(const InitializedEntity &Entity,
                                    ExprResult Init);
  ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
                                       SourceLocation EqualLoc,
                                       ExprResult Init,
                                       bool TopLevelOfInitList = false,
                                       bool AllowExplicit = false);
  ExprResult PerformObjectArgumentInitialization(Expr *From,
                                                 NestedNameSpecifier *Qualifier,
                                                 NamedDecl *FoundDecl,
                                                 CXXMethodDecl *Method);

  ExprResult PerformContextuallyConvertToBool(Expr *From);
  ExprResult PerformContextuallyConvertToObjCPointer(Expr *From);

  /// Contexts in which a converted constant expression is required.
  enum CCEKind {
    CCEK_CaseValue,  ///< Expression in a case label.
    CCEK_Enumerator, ///< Enumerator value with fixed underlying type.
    CCEK_TemplateArg ///< Value of a non-type template parameter.
  };
  ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                              llvm::APSInt &Value, CCEKind CCE);

  ExprResult
  ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *FromE,
                                     const PartialDiagnostic &NotIntDiag,
                                     const PartialDiagnostic &IncompleteDiag,
                                     const PartialDiagnostic &ExplicitConvDiag,
                                     const PartialDiagnostic &ExplicitConvNote,
                                     const PartialDiagnostic &AmbigDiag,
                                     const PartialDiagnostic &AmbigNote,
                                     const PartialDiagnostic &ConvDiag,
                                     bool AllowScopedEnumerations);
  enum ObjCSubscriptKind {
    OS_Array,
    OS_Dictionary,
    OS_Error
  };
  ObjCSubscriptKind CheckSubscriptingKind(Expr *FromE);

  ExprResult PerformObjectMemberConversion(Expr *From,
                                           NestedNameSpecifier *Qualifier,
                                           NamedDecl *FoundDecl,
                                           NamedDecl *Member);

  // Members have to be NamespaceDecl* or TranslationUnitDecl*.
  // TODO: make this is a typesafe union.
  typedef llvm::SmallPtrSet<DeclContext   *, 16> AssociatedNamespaceSet;
  typedef llvm::SmallPtrSet<CXXRecordDecl *, 16> AssociatedClassSet;

  void AddOverloadCandidate(FunctionDecl *Function,
                            DeclAccessPair FoundDecl,
                            llvm::ArrayRef<Expr *> Args,
                            OverloadCandidateSet& CandidateSet,
                            bool SuppressUserConversions = false,
                            bool PartialOverloading = false,
                            bool AllowExplicit = false);
  void AddFunctionCandidates(const UnresolvedSetImpl &Functions,
                             llvm::ArrayRef<Expr *> Args,
                             OverloadCandidateSet& CandidateSet,
                             bool SuppressUserConversions = false,
                            TemplateArgumentListInfo *ExplicitTemplateArgs = 0);
  void AddMethodCandidate(DeclAccessPair FoundDecl,
                          QualType ObjectType,
                          Expr::Classification ObjectClassification,
                          Expr **Args, unsigned NumArgs,
                          OverloadCandidateSet& CandidateSet,
                          bool SuppressUserConversion = false);
  void AddMethodCandidate(CXXMethodDecl *Method,
                          DeclAccessPair FoundDecl,
                          CXXRecordDecl *ActingContext, QualType ObjectType,
                          Expr::Classification ObjectClassification,
                          llvm::ArrayRef<Expr *> Args,
                          OverloadCandidateSet& CandidateSet,
                          bool SuppressUserConversions = false);
  void AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
                                  DeclAccessPair FoundDecl,
                                  CXXRecordDecl *ActingContext,
                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                  QualType ObjectType,
                                  Expr::Classification ObjectClassification,
                                  llvm::ArrayRef<Expr *> Args,
                                  OverloadCandidateSet& CandidateSet,
                                  bool SuppressUserConversions = false);
  void AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate,
                                    DeclAccessPair FoundDecl,
                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                    llvm::ArrayRef<Expr *> Args,
                                    OverloadCandidateSet& CandidateSet,
                                    bool SuppressUserConversions = false);
  void AddConversionCandidate(CXXConversionDecl *Conversion,
                              DeclAccessPair FoundDecl,
                              CXXRecordDecl *ActingContext,
                              Expr *From, QualType ToType,
                              OverloadCandidateSet& CandidateSet);
  void AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate,
                                      DeclAccessPair FoundDecl,
                                      CXXRecordDecl *ActingContext,
                                      Expr *From, QualType ToType,
                                      OverloadCandidateSet &CandidateSet);
  void AddSurrogateCandidate(CXXConversionDecl *Conversion,
                             DeclAccessPair FoundDecl,
                             CXXRecordDecl *ActingContext,
                             const FunctionProtoType *Proto,
                             Expr *Object, llvm::ArrayRef<Expr*> Args,
                             OverloadCandidateSet& CandidateSet);
  void AddMemberOperatorCandidates(OverloadedOperatorKind Op,
                                   SourceLocation OpLoc,
                                   Expr **Args, unsigned NumArgs,
                                   OverloadCandidateSet& CandidateSet,
                                   SourceRange OpRange = SourceRange());
  void AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys,
                           Expr **Args, unsigned NumArgs,
                           OverloadCandidateSet& CandidateSet,
                           bool IsAssignmentOperator = false,
                           unsigned NumContextualBoolArguments = 0);
  void AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
                                    SourceLocation OpLoc,
                                    Expr **Args, unsigned NumArgs,
                                    OverloadCandidateSet& CandidateSet);
  void AddArgumentDependentLookupCandidates(DeclarationName Name,
                                            bool Operator, SourceLocation Loc,
                                            llvm::ArrayRef<Expr *> Args,
                                TemplateArgumentListInfo *ExplicitTemplateArgs,
                                            OverloadCandidateSet& CandidateSet,
                                            bool PartialOverloading = false,
                                        bool StdNamespaceIsAssociated = false);

  // Emit as a 'note' the specific overload candidate
  void NoteOverloadCandidate(FunctionDecl *Fn, QualType DestType = QualType());

  // Emit as a series of 'note's all template and non-templates
  // identified by the expression Expr
  void NoteAllOverloadCandidates(Expr* E, QualType DestType = QualType());

  // [PossiblyAFunctionType]  -->   [Return]
  // NonFunctionType --> NonFunctionType
  // R (A) --> R(A)
  // R (*)(A) --> R (A)
  // R (&)(A) --> R (A)
  // R (S::*)(A) --> R (A)
  QualType ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType);

  FunctionDecl *
  ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
                                     QualType TargetType,
                                     bool Complain,
                                     DeclAccessPair &Found,
                                     bool *pHadMultipleCandidates = 0);

  FunctionDecl *ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
                                                   bool Complain = false,
                                                   DeclAccessPair* Found = 0);

  bool ResolveAndFixSingleFunctionTemplateSpecialization(
                      ExprResult &SrcExpr,
                      bool DoFunctionPointerConverion = false,
                      bool Complain = false,
                      const SourceRange& OpRangeForComplaining = SourceRange(),
                      QualType DestTypeForComplaining = QualType(),
                      unsigned DiagIDForComplaining = 0);


  Expr *FixOverloadedFunctionReference(Expr *E,
                                       DeclAccessPair FoundDecl,
                                       FunctionDecl *Fn);
  ExprResult FixOverloadedFunctionReference(ExprResult,
                                            DeclAccessPair FoundDecl,
                                            FunctionDecl *Fn);

  void AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
                                   llvm::ArrayRef<Expr *> Args,
                                   OverloadCandidateSet &CandidateSet,
                                   bool PartialOverloading = false);

  ExprResult BuildOverloadedCallExpr(Scope *S, Expr *Fn,
                                     UnresolvedLookupExpr *ULE,
                                     SourceLocation LParenLoc,
                                     Expr **Args, unsigned NumArgs,
                                     SourceLocation RParenLoc,
                                     Expr *ExecConfig,
                                     bool AllowTypoCorrection=true);

  ExprResult CreateOverloadedUnaryOp(SourceLocation OpLoc,
                                     unsigned Opc,
                                     const UnresolvedSetImpl &Fns,
                                     Expr *input);

  ExprResult CreateOverloadedBinOp(SourceLocation OpLoc,
                                   unsigned Opc,
                                   const UnresolvedSetImpl &Fns,
                                   Expr *LHS, Expr *RHS);

  ExprResult CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
                                                SourceLocation RLoc,
                                                Expr *Base,Expr *Idx);

  ExprResult
  BuildCallToMemberFunction(Scope *S, Expr *MemExpr,
                            SourceLocation LParenLoc, Expr **Args,
                            unsigned NumArgs, SourceLocation RParenLoc);
  ExprResult
  BuildCallToObjectOfClassType(Scope *S, Expr *Object, SourceLocation LParenLoc,
                               Expr **Args, unsigned NumArgs,
                               SourceLocation RParenLoc);

  ExprResult BuildOverloadedArrowExpr(Scope *S, Expr *Base,
                                      SourceLocation OpLoc);

  /// CheckCallReturnType - Checks that a call expression's return type is
  /// complete. Returns true on failure. The location passed in is the location
  /// that best represents the call.
  bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
                           CallExpr *CE, FunctionDecl *FD);

  /// Helpers for dealing with blocks and functions.
  bool CheckParmsForFunctionDef(ParmVarDecl **Param, ParmVarDecl **ParamEnd,
                                bool CheckParameterNames);
  void CheckCXXDefaultArguments(FunctionDecl *FD);
  void CheckExtraCXXDefaultArguments(Declarator &D);
  Scope *getNonFieldDeclScope(Scope *S);

  /// \name Name lookup
  ///
  /// These routines provide name lookup that is used during semantic
  /// analysis to resolve the various kinds of names (identifiers,
  /// overloaded operator names, constructor names, etc.) into zero or
  /// more declarations within a particular scope. The major entry
  /// points are LookupName, which performs unqualified name lookup,
  /// and LookupQualifiedName, which performs qualified name lookup.
  ///
  /// All name lookup is performed based on some specific criteria,
  /// which specify what names will be visible to name lookup and how
  /// far name lookup should work. These criteria are important both
  /// for capturing language semantics (certain lookups will ignore
  /// certain names, for example) and for performance, since name
  /// lookup is often a bottleneck in the compilation of C++. Name
  /// lookup criteria is specified via the LookupCriteria enumeration.
  ///
  /// The results of name lookup can vary based on the kind of name
  /// lookup performed, the current language, and the translation
  /// unit. In C, for example, name lookup will either return nothing
  /// (no entity found) or a single declaration. In C++, name lookup
  /// can additionally refer to a set of overloaded functions or
  /// result in an ambiguity. All of the possible results of name
  /// lookup are captured by the LookupResult class, which provides
  /// the ability to distinguish among them.
  //@{

  /// @brief Describes the kind of name lookup to perform.
  enum LookupNameKind {
    /// Ordinary name lookup, which finds ordinary names (functions,
    /// variables, typedefs, etc.) in C and most kinds of names
    /// (functions, variables, members, types, etc.) in C++.
    LookupOrdinaryName = 0,
    /// Tag name lookup, which finds the names of enums, classes,
    /// structs, and unions.
    LookupTagName,
    /// Label name lookup.
    LookupLabel,
    /// Member name lookup, which finds the names of
    /// class/struct/union members.
    LookupMemberName,
    /// Look up of an operator name (e.g., operator+) for use with
    /// operator overloading. This lookup is similar to ordinary name
    /// lookup, but will ignore any declarations that are class members.
    LookupOperatorName,
    /// Look up of a name that precedes the '::' scope resolution
    /// operator in C++. This lookup completely ignores operator, object,
    /// function, and enumerator names (C++ [basic.lookup.qual]p1).
    LookupNestedNameSpecifierName,
    /// Look up a namespace name within a C++ using directive or
    /// namespace alias definition, ignoring non-namespace names (C++
    /// [basic.lookup.udir]p1).
    LookupNamespaceName,
    /// Look up all declarations in a scope with the given name,
    /// including resolved using declarations.  This is appropriate
    /// for checking redeclarations for a using declaration.
    LookupUsingDeclName,
    /// Look up an ordinary name that is going to be redeclared as a
    /// name with linkage. This lookup ignores any declarations that
    /// are outside of the current scope unless they have linkage. See
    /// C99 6.2.2p4-5 and C++ [basic.link]p6.
    LookupRedeclarationWithLinkage,
    /// Look up the name of an Objective-C protocol.
    LookupObjCProtocolName,
    /// Look up implicit 'self' parameter of an objective-c method.
    LookupObjCImplicitSelfParam,
    /// \brief Look up any declaration with any name.
    LookupAnyName
  };

  /// \brief Specifies whether (or how) name lookup is being performed for a
  /// redeclaration (vs. a reference).
  enum RedeclarationKind {
    /// \brief The lookup is a reference to this name that is not for the
    /// purpose of redeclaring the name.
    NotForRedeclaration = 0,
    /// \brief The lookup results will be used for redeclaration of a name,
    /// if an entity by that name already exists.
    ForRedeclaration
  };

  /// \brief The possible outcomes of name lookup for a literal operator.
  enum LiteralOperatorLookupResult {
    /// \brief The lookup resulted in an error.
    LOLR_Error,
    /// \brief The lookup found a single 'cooked' literal operator, which
    /// expects a normal literal to be built and passed to it.
    LOLR_Cooked,
    /// \brief The lookup found a single 'raw' literal operator, which expects
    /// a string literal containing the spelling of the literal token.
    LOLR_Raw,
    /// \brief The lookup found an overload set of literal operator templates,
    /// which expect the characters of the spelling of the literal token to be
    /// passed as a non-type template argument pack.
    LOLR_Template
  };

  SpecialMemberOverloadResult *LookupSpecialMember(CXXRecordDecl *D,
                                                   CXXSpecialMember SM,
                                                   bool ConstArg,
                                                   bool VolatileArg,
                                                   bool RValueThis,
                                                   bool ConstThis,
                                                   bool VolatileThis);

private:
  bool CppLookupName(LookupResult &R, Scope *S);

  // \brief The set of known/encountered (unique, canonicalized) NamespaceDecls.
  //
  // The boolean value will be true to indicate that the namespace was loaded
  // from an AST/PCH file, or false otherwise.
  llvm::DenseMap<NamespaceDecl*, bool> KnownNamespaces;

  /// \brief Whether we have already loaded known namespaces from an extenal
  /// source.
  bool LoadedExternalKnownNamespaces;

public:
  /// \brief Look up a name, looking for a single declaration.  Return
  /// null if the results were absent, ambiguous, or overloaded.
  ///
  /// It is preferable to use the elaborated form and explicitly handle
  /// ambiguity and overloaded.
  NamedDecl *LookupSingleName(Scope *S, DeclarationName Name,
                              SourceLocation Loc,
                              LookupNameKind NameKind,
                              RedeclarationKind Redecl
                                = NotForRedeclaration);
  bool LookupName(LookupResult &R, Scope *S,
                  bool AllowBuiltinCreation = false);
  bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
                           bool InUnqualifiedLookup = false);
  bool LookupParsedName(LookupResult &R, Scope *S, CXXScopeSpec *SS,
                        bool AllowBuiltinCreation = false,
                        bool EnteringContext = false);
  ObjCProtocolDecl *LookupProtocol(IdentifierInfo *II, SourceLocation IdLoc,
                                   RedeclarationKind Redecl
                                     = NotForRedeclaration);

  void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
                                    QualType T1, QualType T2,
                                    UnresolvedSetImpl &Functions);

  LabelDecl *LookupOrCreateLabel(IdentifierInfo *II, SourceLocation IdentLoc,
                                 SourceLocation GnuLabelLoc = SourceLocation());

  DeclContextLookupResult LookupConstructors(CXXRecordDecl *Class);
  CXXConstructorDecl *LookupDefaultConstructor(CXXRecordDecl *Class);
  CXXConstructorDecl *LookupCopyingConstructor(CXXRecordDecl *Class,
                                               unsigned Quals,
                                               bool *ConstParam = 0);
  CXXMethodDecl *LookupCopyingAssignment(CXXRecordDecl *Class, unsigned Quals,
                                         bool RValueThis, unsigned ThisQuals,
                                         bool *ConstParam = 0);
  CXXConstructorDecl *LookupMovingConstructor(CXXRecordDecl *Class);
  CXXMethodDecl *LookupMovingAssignment(CXXRecordDecl *Class, bool RValueThis,
                                        unsigned ThisQuals);
  CXXDestructorDecl *LookupDestructor(CXXRecordDecl *Class);

  LiteralOperatorLookupResult LookupLiteralOperator(Scope *S, LookupResult &R,
                                                    ArrayRef<QualType> ArgTys,
                                                    bool AllowRawAndTemplate);

  void ArgumentDependentLookup(DeclarationName Name, bool Operator,
                               SourceLocation Loc,
                               llvm::ArrayRef<Expr *> Args,
                               ADLResult &Functions,
                               bool StdNamespaceIsAssociated = false);

  void LookupVisibleDecls(Scope *S, LookupNameKind Kind,
                          VisibleDeclConsumer &Consumer,
                          bool IncludeGlobalScope = true);
  void LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
                          VisibleDeclConsumer &Consumer,
                          bool IncludeGlobalScope = true);

  TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
                             Sema::LookupNameKind LookupKind,
                             Scope *S, CXXScopeSpec *SS,
                             CorrectionCandidateCallback &CCC,
                             DeclContext *MemberContext = 0,
                             bool EnteringContext = false,
                             const ObjCObjectPointerType *OPT = 0);

  void FindAssociatedClassesAndNamespaces(llvm::ArrayRef<Expr *> Args,
                                   AssociatedNamespaceSet &AssociatedNamespaces,
                                   AssociatedClassSet &AssociatedClasses);

  void FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
                            bool ConsiderLinkage,
                            bool ExplicitInstantiationOrSpecialization);

  bool DiagnoseAmbiguousLookup(LookupResult &Result);
  //@}

  ObjCInterfaceDecl *getObjCInterfaceDecl(IdentifierInfo *&Id,
                                          SourceLocation IdLoc,
                                          bool TypoCorrection = false);
  NamedDecl *LazilyCreateBuiltin(IdentifierInfo *II, unsigned ID,
                                 Scope *S, bool ForRedeclaration,
                                 SourceLocation Loc);
  NamedDecl *ImplicitlyDefineFunction(SourceLocation Loc, IdentifierInfo &II,
                                      Scope *S);
  void AddKnownFunctionAttributes(FunctionDecl *FD);

  // More parsing and symbol table subroutines.

  // Decl attributes - this routine is the top level dispatcher.
  void ProcessDeclAttributes(Scope *S, Decl *D, const Declarator &PD,
                           bool NonInheritable = true, bool Inheritable = true);
  void ProcessDeclAttributeList(Scope *S, Decl *D, const AttributeList *AL,
                           bool NonInheritable = true, bool Inheritable = true);
  bool ProcessAccessDeclAttributeList(AccessSpecDecl *ASDecl,
                                      const AttributeList *AttrList);

  void checkUnusedDeclAttributes(Declarator &D);

  bool CheckRegparmAttr(const AttributeList &attr, unsigned &value);
  bool CheckCallingConvAttr(const AttributeList &attr, CallingConv &CC);
  bool CheckNoReturnAttr(const AttributeList &attr);

  /// \brief Stmt attributes - this routine is the top level dispatcher.
  StmtResult ProcessStmtAttributes(Stmt *Stmt, AttributeList *Attrs,
                                   SourceRange Range);

  void WarnUndefinedMethod(SourceLocation ImpLoc, ObjCMethodDecl *method,
                           bool &IncompleteImpl, unsigned DiagID);
  void WarnConflictingTypedMethods(ObjCMethodDecl *Method,
                                   ObjCMethodDecl *MethodDecl,
                                   bool IsProtocolMethodDecl);

  void CheckConflictingOverridingMethod(ObjCMethodDecl *Method,
                                   ObjCMethodDecl *Overridden,
                                   bool IsProtocolMethodDecl);

  /// WarnExactTypedMethods - This routine issues a warning if method
  /// implementation declaration matches exactly that of its declaration.
  void WarnExactTypedMethods(ObjCMethodDecl *Method,
                             ObjCMethodDecl *MethodDecl,
                             bool IsProtocolMethodDecl);

  bool isPropertyReadonly(ObjCPropertyDecl *PropertyDecl,
                          ObjCInterfaceDecl *IDecl);

  typedef llvm::DenseSet<Selector, llvm::DenseMapInfo<Selector> > SelectorSet;
  typedef llvm::DenseMap<Selector, ObjCMethodDecl*> ProtocolsMethodsMap;

  /// CheckProtocolMethodDefs - This routine checks unimplemented
  /// methods declared in protocol, and those referenced by it.
  /// \param IDecl - Used for checking for methods which may have been
  /// inherited.
  void CheckProtocolMethodDefs(SourceLocation ImpLoc,
                               ObjCProtocolDecl *PDecl,
                               bool& IncompleteImpl,
                               const SelectorSet &InsMap,
                               const SelectorSet &ClsMap,
                               ObjCContainerDecl *CDecl);

  /// CheckImplementationIvars - This routine checks if the instance variables
  /// listed in the implelementation match those listed in the interface.
  void CheckImplementationIvars(ObjCImplementationDecl *ImpDecl,
                                ObjCIvarDecl **Fields, unsigned nIvars,
                                SourceLocation Loc);

  /// ImplMethodsVsClassMethods - This is main routine to warn if any method
  /// remains unimplemented in the class or category @implementation.
  void ImplMethodsVsClassMethods(Scope *S, ObjCImplDecl* IMPDecl,
                                 ObjCContainerDecl* IDecl,
                                 bool IncompleteImpl = false);

  /// DiagnoseUnimplementedProperties - This routine warns on those properties
  /// which must be implemented by this implementation.
  void DiagnoseUnimplementedProperties(Scope *S, ObjCImplDecl* IMPDecl,
                                       ObjCContainerDecl *CDecl,
                                       const SelectorSet &InsMap);

  /// DefaultSynthesizeProperties - This routine default synthesizes all
  /// properties which must be synthesized in class's @implementation.
  void DefaultSynthesizeProperties (Scope *S, ObjCImplDecl* IMPDecl,
                                    ObjCInterfaceDecl *IDecl);
  void DefaultSynthesizeProperties(Scope *S, Decl *D);

  /// CollectImmediateProperties - This routine collects all properties in
  /// the class and its conforming protocols; but not those it its super class.
  void CollectImmediateProperties(ObjCContainerDecl *CDecl,
            llvm::DenseMap<IdentifierInfo *, ObjCPropertyDecl*>& PropMap,
            llvm::DenseMap<IdentifierInfo *, ObjCPropertyDecl*>& SuperPropMap);


  /// LookupPropertyDecl - Looks up a property in the current class and all
  /// its protocols.
  ObjCPropertyDecl *LookupPropertyDecl(const ObjCContainerDecl *CDecl,
                                       IdentifierInfo *II);

  /// Called by ActOnProperty to handle @property declarations in
  ////  class extensions.
  Decl *HandlePropertyInClassExtension(Scope *S,
                                       SourceLocation AtLoc,
                                       SourceLocation LParenLoc,
                                       FieldDeclarator &FD,
                                       Selector GetterSel,
                                       Selector SetterSel,
                                       const bool isAssign,
                                       const bool isReadWrite,
                                       const unsigned Attributes,
                                       const unsigned AttributesAsWritten,
                                       bool *isOverridingProperty,
                                       TypeSourceInfo *T,
                                       tok::ObjCKeywordKind MethodImplKind);

  /// Called by ActOnProperty and HandlePropertyInClassExtension to
  ///  handle creating the ObjcPropertyDecl for a category or @interface.
  ObjCPropertyDecl *CreatePropertyDecl(Scope *S,
                                       ObjCContainerDecl *CDecl,
                                       SourceLocation AtLoc,
                                       SourceLocation LParenLoc,
                                       FieldDeclarator &FD,
                                       Selector GetterSel,
                                       Selector SetterSel,
                                       const bool isAssign,
                                       const bool isReadWrite,
                                       const unsigned Attributes,
                                       const unsigned AttributesAsWritten,
                                       TypeSourceInfo *T,
                                       tok::ObjCKeywordKind MethodImplKind,
                                       DeclContext *lexicalDC = 0);

  /// AtomicPropertySetterGetterRules - This routine enforces the rule (via
  /// warning) when atomic property has one but not the other user-declared
  /// setter or getter.
  void AtomicPropertySetterGetterRules(ObjCImplDecl* IMPDecl,
                                       ObjCContainerDecl* IDecl);

  void DiagnoseOwningPropertyGetterSynthesis(const ObjCImplementationDecl *D);

  void DiagnoseDuplicateIvars(ObjCInterfaceDecl *ID, ObjCInterfaceDecl *SID);

  enum MethodMatchStrategy {
    MMS_loose,
    MMS_strict
  };

  /// MatchTwoMethodDeclarations - Checks if two methods' type match and returns
  /// true, or false, accordingly.
  bool MatchTwoMethodDeclarations(const ObjCMethodDecl *Method,
                                  const ObjCMethodDecl *PrevMethod,
                                  MethodMatchStrategy strategy = MMS_strict);

  /// MatchAllMethodDeclarations - Check methods declaraed in interface or
  /// or protocol against those declared in their implementations.
  void MatchAllMethodDeclarations(const SelectorSet &InsMap,
                                  const SelectorSet &ClsMap,
                                  SelectorSet &InsMapSeen,
                                  SelectorSet &ClsMapSeen,
                                  ObjCImplDecl* IMPDecl,
                                  ObjCContainerDecl* IDecl,
                                  bool &IncompleteImpl,
                                  bool ImmediateClass,
                                  bool WarnCategoryMethodImpl=false);

  /// CheckCategoryVsClassMethodMatches - Checks that methods implemented in
  /// category matches with those implemented in its primary class and
  /// warns each time an exact match is found.
  void CheckCategoryVsClassMethodMatches(ObjCCategoryImplDecl *CatIMP);

  /// \brief Add the given method to the list of globally-known methods.
  void addMethodToGlobalList(ObjCMethodList *List, ObjCMethodDecl *Method);

private:
  /// AddMethodToGlobalPool - Add an instance or factory method to the global
  /// pool. See descriptoin of AddInstanceMethodToGlobalPool.
  void AddMethodToGlobalPool(ObjCMethodDecl *Method, bool impl, bool instance);

  /// LookupMethodInGlobalPool - Returns the instance or factory method and
  /// optionally warns if there are multiple signatures.
  ObjCMethodDecl *LookupMethodInGlobalPool(Selector Sel, SourceRange R,
                                           bool receiverIdOrClass,
                                           bool warn, bool instance);

public:
  /// AddInstanceMethodToGlobalPool - All instance methods in a translation
  /// unit are added to a global pool. This allows us to efficiently associate
  /// a selector with a method declaraation for purposes of typechecking
  /// messages sent to "id" (where the class of the object is unknown).
  void AddInstanceMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
    AddMethodToGlobalPool(Method, impl, /*instance*/true);
  }

  /// AddFactoryMethodToGlobalPool - Same as above, but for factory methods.
  void AddFactoryMethodToGlobalPool(ObjCMethodDecl *Method, bool impl=false) {
    AddMethodToGlobalPool(Method, impl, /*instance*/false);
  }

  /// AddAnyMethodToGlobalPool - Add any method, instance or factory to global
  /// pool.
  void AddAnyMethodToGlobalPool(Decl *D);

  /// LookupInstanceMethodInGlobalPool - Returns the method and warns if
  /// there are multiple signatures.
  ObjCMethodDecl *LookupInstanceMethodInGlobalPool(Selector Sel, SourceRange R,
                                                   bool receiverIdOrClass=false,
                                                   bool warn=true) {
    return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                    warn, /*instance*/true);
  }

  /// LookupFactoryMethodInGlobalPool - Returns the method and warns if
  /// there are multiple signatures.
  ObjCMethodDecl *LookupFactoryMethodInGlobalPool(Selector Sel, SourceRange R,
                                                  bool receiverIdOrClass=false,
                                                  bool warn=true) {
    return LookupMethodInGlobalPool(Sel, R, receiverIdOrClass,
                                    warn, /*instance*/false);
  }

  /// LookupImplementedMethodInGlobalPool - Returns the method which has an
  /// implementation.
  ObjCMethodDecl *LookupImplementedMethodInGlobalPool(Selector Sel);

  /// CollectIvarsToConstructOrDestruct - Collect those ivars which require
  /// initialization.
  void CollectIvarsToConstructOrDestruct(ObjCInterfaceDecl *OI,
                                  SmallVectorImpl<ObjCIvarDecl*> &Ivars);

  //===--------------------------------------------------------------------===//
  // Statement Parsing Callbacks: SemaStmt.cpp.
public:
  class FullExprArg {
  public:
    FullExprArg(Sema &actions) : E(0) { }

    // FIXME: The const_cast here is ugly. RValue references would make this
    // much nicer (or we could duplicate a bunch of the move semantics
    // emulation code from Ownership.h).
    FullExprArg(const FullExprArg& Other) : E(Other.E) {}

    ExprResult release() {
      return move(E);
    }

    Expr *get() const { return E; }

    Expr *operator->() {
      return E;
    }

  private:
    // FIXME: No need to make the entire Sema class a friend when it's just
    // Sema::MakeFullExpr that needs access to the constructor below.
    friend class Sema;

    explicit FullExprArg(Expr *expr) : E(expr) {}

    Expr *E;
  };

  FullExprArg MakeFullExpr(Expr *Arg) {
    return FullExprArg(ActOnFinishFullExpr(Arg).release());
  }

  StmtResult ActOnExprStmt(FullExprArg Expr);

  StmtResult ActOnNullStmt(SourceLocation SemiLoc,
                           bool HasLeadingEmptyMacro = false);

  void ActOnStartOfCompoundStmt();
  void ActOnFinishOfCompoundStmt();
  StmtResult ActOnCompoundStmt(SourceLocation L, SourceLocation R,
                                       MultiStmtArg Elts,
                                       bool isStmtExpr);

  /// \brief A RAII object to enter scope of a compound statement.
  class CompoundScopeRAII {
  public:
    CompoundScopeRAII(Sema &S): S(S) {
      S.ActOnStartOfCompoundStmt();
    }

    ~CompoundScopeRAII() {
      S.ActOnFinishOfCompoundStmt();
    }

  private:
    Sema &S;
  };

  StmtResult ActOnDeclStmt(DeclGroupPtrTy Decl,
                                   SourceLocation StartLoc,
                                   SourceLocation EndLoc);
  void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);
  StmtResult ActOnForEachLValueExpr(Expr *E);
  StmtResult ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal,
                                   SourceLocation DotDotDotLoc, Expr *RHSVal,
                                   SourceLocation ColonLoc);
  void ActOnCaseStmtBody(Stmt *CaseStmt, Stmt *SubStmt);

  StmtResult ActOnDefaultStmt(SourceLocation DefaultLoc,
                                      SourceLocation ColonLoc,
                                      Stmt *SubStmt, Scope *CurScope);
  StmtResult ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
                            SourceLocation ColonLoc, Stmt *SubStmt);

  StmtResult ActOnAttributedStmt(SourceLocation AttrLoc, const AttrVec &Attrs,
                                 Stmt *SubStmt);

  StmtResult ActOnIfStmt(SourceLocation IfLoc,
                         FullExprArg CondVal, Decl *CondVar,
                         Stmt *ThenVal,
                         SourceLocation ElseLoc, Stmt *ElseVal);
  StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
                                            Expr *Cond,
                                            Decl *CondVar);
  StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
                                           Stmt *Switch, Stmt *Body);
  StmtResult ActOnWhileStmt(SourceLocation WhileLoc,
                            FullExprArg Cond,
                            Decl *CondVar, Stmt *Body);
  StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
                                 SourceLocation WhileLoc,
                                 SourceLocation CondLParen, Expr *Cond,
                                 SourceLocation CondRParen);

  StmtResult ActOnForStmt(SourceLocation ForLoc,
                          SourceLocation LParenLoc,
                          Stmt *First, FullExprArg Second,
                          Decl *SecondVar,
                          FullExprArg Third,
                          SourceLocation RParenLoc,
                          Stmt *Body);
  ExprResult ActOnObjCForCollectionOperand(SourceLocation forLoc,
                                           Expr *collection);
  StmtResult ActOnObjCForCollectionStmt(SourceLocation ForColLoc,
                                        SourceLocation LParenLoc,
                                        Stmt *First, Expr *Second,
                                        SourceLocation RParenLoc, Stmt *Body);
  StmtResult ActOnCXXForRangeStmt(SourceLocation ForLoc,
                                  SourceLocation LParenLoc, Stmt *LoopVar,
                                  SourceLocation ColonLoc, Expr *Collection,
                                  SourceLocation RParenLoc);
  StmtResult BuildCXXForRangeStmt(SourceLocation ForLoc,
                                  SourceLocation ColonLoc,
                                  Stmt *RangeDecl, Stmt *BeginEndDecl,
                                  Expr *Cond, Expr *Inc,
                                  Stmt *LoopVarDecl,
                                  SourceLocation RParenLoc);
  StmtResult FinishCXXForRangeStmt(Stmt *ForRange, Stmt *Body);

  StmtResult ActOnGotoStmt(SourceLocation GotoLoc,
                           SourceLocation LabelLoc,
                           LabelDecl *TheDecl);
  StmtResult ActOnIndirectGotoStmt(SourceLocation GotoLoc,
                                   SourceLocation StarLoc,
                                   Expr *DestExp);
  StmtResult ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope);
  StmtResult ActOnBreakStmt(SourceLocation GotoLoc, Scope *CurScope);

  const VarDecl *getCopyElisionCandidate(QualType ReturnType, Expr *E,
                                         bool AllowFunctionParameters);

  StmtResult ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp);
  StmtResult ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp);

  StmtResult ActOnAsmStmt(SourceLocation AsmLoc,
                          bool IsSimple, bool IsVolatile,
                          unsigned NumOutputs, unsigned NumInputs,
                          IdentifierInfo **Names,
                          MultiExprArg Constraints,
                          MultiExprArg Exprs,
                          Expr *AsmString,
                          MultiExprArg Clobbers,
                          SourceLocation RParenLoc,
                          bool MSAsm = false);


  VarDecl *BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType ExceptionType,
                                  SourceLocation StartLoc,
                                  SourceLocation IdLoc, IdentifierInfo *Id,
                                  bool Invalid = false);

  Decl *ActOnObjCExceptionDecl(Scope *S, Declarator &D);

  StmtResult ActOnObjCAtCatchStmt(SourceLocation AtLoc, SourceLocation RParen,
                                  Decl *Parm, Stmt *Body);

  StmtResult ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body);

  StmtResult ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
                                MultiStmtArg Catch, Stmt *Finally);

  StmtResult BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw);
  StmtResult ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
                                  Scope *CurScope);
  ExprResult ActOnObjCAtSynchronizedOperand(SourceLocation atLoc,
                                            Expr *operand);
  StmtResult ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc,
                                         Expr *SynchExpr,
                                         Stmt *SynchBody);

  StmtResult ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body);

  VarDecl *BuildExceptionDeclaration(Scope *S, TypeSourceInfo *TInfo,
                                     SourceLocation StartLoc,
                                     SourceLocation IdLoc,
                                     IdentifierInfo *Id);

  Decl *ActOnExceptionDeclarator(Scope *S, Declarator &D);

  StmtResult ActOnCXXCatchBlock(SourceLocation CatchLoc,
                                Decl *ExDecl, Stmt *HandlerBlock);
  StmtResult ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
                              MultiStmtArg Handlers);

  StmtResult ActOnSEHTryBlock(bool IsCXXTry, // try (true) or __try (false) ?
                              SourceLocation TryLoc,
                              Stmt *TryBlock,
                              Stmt *Handler);

  StmtResult ActOnSEHExceptBlock(SourceLocation Loc,
                                 Expr *FilterExpr,
                                 Stmt *Block);

  StmtResult ActOnSEHFinallyBlock(SourceLocation Loc,
                                  Stmt *Block);

  void DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock);

  bool ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const;

  /// \brief If it's a file scoped decl that must warn if not used, keep track
  /// of it.
  void MarkUnusedFileScopedDecl(const DeclaratorDecl *D);

  /// DiagnoseUnusedExprResult - If the statement passed in is an expression
  /// whose result is unused, warn.
  void DiagnoseUnusedExprResult(const Stmt *S);
  void DiagnoseUnusedDecl(const NamedDecl *ND);

  /// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
  /// statement as a \p Body, and it is located on the same line.
  ///
  /// This helps prevent bugs due to typos, such as:
  ///     if (condition);
  ///       do_stuff();
  void DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
                             const Stmt *Body,
                             unsigned DiagID);

  /// Warn if a for/while loop statement \p S, which is followed by
  /// \p PossibleBody, has a suspicious null statement as a body.
  void DiagnoseEmptyLoopBody(const Stmt *S,
                             const Stmt *PossibleBody);

  ParsingDeclState PushParsingDeclaration() {
    return DelayedDiagnostics.pushParsingDecl();
  }
  void PopParsingDeclaration(ParsingDeclState state, Decl *decl) {
    DelayedDiagnostics::popParsingDecl(*this, state, decl);
  }

  typedef ProcessingContextState ParsingClassState;
  ParsingClassState PushParsingClass() {
    return DelayedDiagnostics.pushContext();
  }
  void PopParsingClass(ParsingClassState state) {
    DelayedDiagnostics.popContext(state);
  }

  void EmitDeprecationWarning(NamedDecl *D, StringRef Message,
                              SourceLocation Loc,
                              const ObjCInterfaceDecl *UnknownObjCClass=0);

  void HandleDelayedDeprecationCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);

  bool makeUnavailableInSystemHeader(SourceLocation loc,
                                     StringRef message);

  //===--------------------------------------------------------------------===//
  // Expression Parsing Callbacks: SemaExpr.cpp.

  bool CanUseDecl(NamedDecl *D);
  bool DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc,
                         const ObjCInterfaceDecl *UnknownObjCClass=0);
  void NoteDeletedFunction(FunctionDecl *FD);
  std::string getDeletedOrUnavailableSuffix(const FunctionDecl *FD);
  bool DiagnosePropertyAccessorMismatch(ObjCPropertyDecl *PD,
                                        ObjCMethodDecl *Getter,
                                        SourceLocation Loc);
  void DiagnoseSentinelCalls(NamedDecl *D, SourceLocation Loc,
                             Expr **Args, unsigned NumArgs);

  void PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext,
                                       Decl *LambdaContextDecl = 0,
                                       bool IsDecltype = false);

  void PopExpressionEvaluationContext();

  void DiscardCleanupsInEvaluationContext();

  ExprResult TranformToPotentiallyEvaluated(Expr *E);
  ExprResult HandleExprEvaluationContextForTypeof(Expr *E);

  ExprResult ActOnConstantExpression(ExprResult Res);

  // Functions for marking a declaration referenced.  These functions also
  // contain the relevant logic for marking if a reference to a function or
  // variable is an odr-use (in the C++11 sense).  There are separate variants
  // for expressions referring to a decl; these exist because odr-use marking
  // needs to be delayed for some constant variables when we build one of the
  // named expressions.
  void MarkAnyDeclReferenced(SourceLocation Loc, Decl *D);
  void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func);
  void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
  void MarkDeclRefReferenced(DeclRefExpr *E);
  void MarkMemberReferenced(MemberExpr *E);

  void UpdateMarkingForLValueToRValue(Expr *E);
  void CleanupVarDeclMarking();

  enum TryCaptureKind {
    TryCapture_Implicit, TryCapture_ExplicitByVal, TryCapture_ExplicitByRef
  };

  /// \brief Try to capture the given variable.
  ///
  /// \param Var The variable to capture.
  ///
  /// \param Loc The location at which the capture occurs.
  ///
  /// \param Kind The kind of capture, which may be implicit (for either a
  /// block or a lambda), or explicit by-value or by-reference (for a lambda).
  ///
  /// \param EllipsisLoc The location of the ellipsis, if one is provided in
  /// an explicit lambda capture.
  ///
  /// \param BuildAndDiagnose Whether we are actually supposed to add the
  /// captures or diagnose errors. If false, this routine merely check whether
  /// the capture can occur without performing the capture itself or complaining
  /// if the variable cannot be captured.
  ///
  /// \param CaptureType Will be set to the type of the field used to capture
  /// this variable in the innermost block or lambda. Only valid when the
  /// variable can be captured.
  ///
  /// \param DeclRefType Will be set to the type of a refernce to the capture
  /// from within the current scope. Only valid when the variable can be
  /// captured.
  ///
  /// \returns true if an error occurred (i.e., the variable cannot be
  /// captured) and false if the capture succeeded.
  bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc, TryCaptureKind Kind,
                          SourceLocation EllipsisLoc, bool BuildAndDiagnose,
                          QualType &CaptureType,
                          QualType &DeclRefType);

  /// \brief Try to capture the given variable.
  bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc,
                          TryCaptureKind Kind = TryCapture_Implicit,
                          SourceLocation EllipsisLoc = SourceLocation());

  /// \brief Given a variable, determine the type that a reference to that
  /// variable will have in the given scope.
  QualType getCapturedDeclRefType(VarDecl *Var, SourceLocation Loc);

  void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
  void MarkDeclarationsReferencedInExpr(Expr *E,
                                        bool SkipLocalVariables = false);

  /// \brief Try to recover by turning the given expression into a
  /// call.  Returns true if recovery was attempted or an error was
  /// emitted; this may also leave the ExprResult invalid.
  bool tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
                            bool ForceComplain = false,
                            bool (*IsPlausibleResult)(QualType) = 0);

  /// \brief Figure out if an expression could be turned into a call.
  bool isExprCallable(const Expr &E, QualType &ZeroArgCallReturnTy,
                      UnresolvedSetImpl &NonTemplateOverloads);

  /// \brief Conditionally issue a diagnostic based on the current
  /// evaluation context.
  ///
  /// \param stmt - If stmt is non-null, delay reporting the diagnostic until
  ///  the function body is parsed, and then do a basic reachability analysis to
  ///  determine if the statement is reachable.  If it is unreachable, the
  ///  diagnostic will not be emitted.
  bool DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
                           const PartialDiagnostic &PD);

  // Primary Expressions.
  SourceRange getExprRange(Expr *E) const;

  ExprResult ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
                               SourceLocation TemplateKWLoc,
                               UnqualifiedId &Id,
                               bool HasTrailingLParen, bool IsAddressOfOperand,
                               CorrectionCandidateCallback *CCC = 0);

  void DecomposeUnqualifiedId(const UnqualifiedId &Id,
                              TemplateArgumentListInfo &Buffer,
                              DeclarationNameInfo &NameInfo,
                              const TemplateArgumentListInfo *&TemplateArgs);

  bool DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
                           CorrectionCandidateCallback &CCC,
                           TemplateArgumentListInfo *ExplicitTemplateArgs = 0,
                       llvm::ArrayRef<Expr *> Args = llvm::ArrayRef<Expr *>());

  ExprResult LookupInObjCMethod(LookupResult &LookUp, Scope *S,
                                IdentifierInfo *II,
                                bool AllowBuiltinCreation=false);

  ExprResult ActOnDependentIdExpression(const CXXScopeSpec &SS,
                                        SourceLocation TemplateKWLoc,
                                        const DeclarationNameInfo &NameInfo,
                                        bool isAddressOfOperand,
                                const TemplateArgumentListInfo *TemplateArgs);

  ExprResult BuildDeclRefExpr(ValueDecl *D, QualType Ty,
                              ExprValueKind VK,
                              SourceLocation Loc,
                              const CXXScopeSpec *SS = 0);
  ExprResult BuildDeclRefExpr(ValueDecl *D, QualType Ty,
                              ExprValueKind VK,
                              const DeclarationNameInfo &NameInfo,
                              const CXXScopeSpec *SS = 0);
  ExprResult
  BuildAnonymousStructUnionMemberReference(const CXXScopeSpec &SS,
                                           SourceLocation nameLoc,
                                           IndirectFieldDecl *indirectField,
                                           Expr *baseObjectExpr = 0,
                                      SourceLocation opLoc = SourceLocation());
  ExprResult BuildPossibleImplicitMemberExpr(const CXXScopeSpec &SS,
                                             SourceLocation TemplateKWLoc,
                                             LookupResult &R,
                                const TemplateArgumentListInfo *TemplateArgs);
  ExprResult BuildImplicitMemberExpr(const CXXScopeSpec &SS,
                                     SourceLocation TemplateKWLoc,
                                     LookupResult &R,
                                const TemplateArgumentListInfo *TemplateArgs,
                                     bool IsDefiniteInstance);
  bool UseArgumentDependentLookup(const CXXScopeSpec &SS,
                                  const LookupResult &R,
                                  bool HasTrailingLParen);

  ExprResult BuildQualifiedDeclarationNameExpr(CXXScopeSpec &SS,
                                         const DeclarationNameInfo &NameInfo);
  ExprResult BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
                                       SourceLocation TemplateKWLoc,
                                const DeclarationNameInfo &NameInfo,
                                const TemplateArgumentListInfo *TemplateArgs);

  ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS,
                                      LookupResult &R,
                                      bool NeedsADL);
  ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS,
                                      const DeclarationNameInfo &NameInfo,
                                      NamedDecl *D);

  ExprResult BuildLiteralOperatorCall(LookupResult &R,
                                      DeclarationNameInfo &SuffixInfo,
                                      ArrayRef<Expr*> Args,
                                      SourceLocation LitEndLoc,
                            TemplateArgumentListInfo *ExplicitTemplateArgs = 0);

  ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
  ExprResult ActOnIntegerConstant(SourceLocation Loc, uint64_t Val);
  ExprResult ActOnNumericConstant(const Token &Tok, Scope *UDLScope = 0);
  ExprResult ActOnCharacterConstant(const Token &Tok, Scope *UDLScope = 0);
  ExprResult ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E);
  ExprResult ActOnParenListExpr(SourceLocation L,
                                SourceLocation R,
                                MultiExprArg Val);

  /// ActOnStringLiteral - The specified tokens were lexed as pasted string
  /// fragments (e.g. "foo" "bar" L"baz").
  ExprResult ActOnStringLiteral(const Token *StringToks, unsigned NumStringToks,
                                Scope *UDLScope = 0);

  ExprResult ActOnGenericSelectionExpr(SourceLocation KeyLoc,
                                       SourceLocation DefaultLoc,
                                       SourceLocation RParenLoc,
                                       Expr *ControllingExpr,
                                       MultiTypeArg ArgTypes,
                                       MultiExprArg ArgExprs);
  ExprResult CreateGenericSelectionExpr(SourceLocation KeyLoc,
                                        SourceLocation DefaultLoc,
                                        SourceLocation RParenLoc,
                                        Expr *ControllingExpr,
                                        TypeSourceInfo **Types,
                                        Expr **Exprs,
                                        unsigned NumAssocs);

  // Binary/Unary Operators.  'Tok' is the token for the operator.
  ExprResult CreateBuiltinUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
                                  Expr *InputExpr);
  ExprResult BuildUnaryOp(Scope *S, SourceLocation OpLoc,
                          UnaryOperatorKind Opc, Expr *Input);
  ExprResult ActOnUnaryOp(Scope *S, SourceLocation OpLoc,
                          tok::TokenKind Op, Expr *Input);

  ExprResult CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
                                            SourceLocation OpLoc,
                                            UnaryExprOrTypeTrait ExprKind,
                                            SourceRange R);
  ExprResult CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
                                            UnaryExprOrTypeTrait ExprKind);
  ExprResult
    ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
                                  UnaryExprOrTypeTrait ExprKind,
                                  bool IsType, void *TyOrEx,
                                  const SourceRange &ArgRange);

  ExprResult CheckPlaceholderExpr(Expr *E);
  bool CheckVecStepExpr(Expr *E);

  bool CheckUnaryExprOrTypeTraitOperand(Expr *E, UnaryExprOrTypeTrait ExprKind);
  bool CheckUnaryExprOrTypeTraitOperand(QualType ExprType, SourceLocation OpLoc,
                                        SourceRange ExprRange,
                                        UnaryExprOrTypeTrait ExprKind);
  ExprResult ActOnSizeofParameterPackExpr(Scope *S,
                                          SourceLocation OpLoc,
                                          IdentifierInfo &Name,
                                          SourceLocation NameLoc,
                                          SourceLocation RParenLoc);
  ExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
                                 tok::TokenKind Kind, Expr *Input);

  ExprResult ActOnArraySubscriptExpr(Scope *S, Expr *Base, SourceLocation LLoc,
                                     Expr *Idx, SourceLocation RLoc);
  ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
                                             Expr *Idx, SourceLocation RLoc);

  ExprResult BuildMemberReferenceExpr(Expr *Base, QualType BaseType,
                                      SourceLocation OpLoc, bool IsArrow,
                                      CXXScopeSpec &SS,
                                      SourceLocation TemplateKWLoc,
                                      NamedDecl *FirstQualifierInScope,
                                const DeclarationNameInfo &NameInfo,
                                const TemplateArgumentListInfo *TemplateArgs);

  ExprResult BuildMemberReferenceExpr(Expr *Base, QualType BaseType,
                                      SourceLocation OpLoc, bool IsArrow,
                                      const CXXScopeSpec &SS,
                                      SourceLocation TemplateKWLoc,
                                      NamedDecl *FirstQualifierInScope,
                                      LookupResult &R,
                                 const TemplateArgumentListInfo *TemplateArgs,
                                      bool SuppressQualifierCheck = false);

  ExprResult PerformMemberExprBaseConversion(Expr *Base, bool IsArrow);
  ExprResult LookupMemberExpr(LookupResult &R, ExprResult &Base,
                              bool &IsArrow, SourceLocation OpLoc,
                              CXXScopeSpec &SS,
                              Decl *ObjCImpDecl,
                              bool HasTemplateArgs);

  bool CheckQualifiedMemberReference(Expr *BaseExpr, QualType BaseType,
                                     const CXXScopeSpec &SS,
                                     const LookupResult &R);

  ExprResult ActOnDependentMemberExpr(Expr *Base, QualType BaseType,
                                      bool IsArrow, SourceLocation OpLoc,
                                      const CXXScopeSpec &SS,
                                      SourceLocation TemplateKWLoc,
                                      NamedDecl *FirstQualifierInScope,
                               const DeclarationNameInfo &NameInfo,
                               const TemplateArgumentListInfo *TemplateArgs);

  ExprResult ActOnMemberAccessExpr(Scope *S, Expr *Base,
                                   SourceLocation OpLoc,
                                   tok::TokenKind OpKind,
                                   CXXScopeSpec &SS,
                                   SourceLocation TemplateKWLoc,
                                   UnqualifiedId &Member,
                                   Decl *ObjCImpDecl,
                                   bool HasTrailingLParen);

  void ActOnDefaultCtorInitializers(Decl *CDtorDecl);
  bool ConvertArgumentsForCall(CallExpr *Call, Expr *Fn,
                               FunctionDecl *FDecl,
                               const FunctionProtoType *Proto,
                               Expr **Args, unsigned NumArgs,
                               SourceLocation RParenLoc,
                               bool ExecConfig = false);
  void CheckStaticArrayArgument(SourceLocation CallLoc,
                                ParmVarDecl *Param,
                                const Expr *ArgExpr);

  /// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
  /// This provides the location of the left/right parens and a list of comma
  /// locations.
  ExprResult ActOnCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
                           MultiExprArg ArgExprs, SourceLocation RParenLoc,
                           Expr *ExecConfig = 0, bool IsExecConfig = false);
  ExprResult BuildResolvedCallExpr(Expr *Fn, NamedDecl *NDecl,
                                   SourceLocation LParenLoc,
                                   Expr **Args, unsigned NumArgs,
                                   SourceLocation RParenLoc,
                                   Expr *Config = 0,
                                   bool IsExecConfig = false);

  ExprResult ActOnCUDAExecConfigExpr(Scope *S, SourceLocation LLLLoc,
                                     MultiExprArg ExecConfig,
                                     SourceLocation GGGLoc);

  ExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
                           Declarator &D, ParsedType &Ty,
                           SourceLocation RParenLoc, Expr *CastExpr);
  ExprResult BuildCStyleCastExpr(SourceLocation LParenLoc,
                                 TypeSourceInfo *Ty,
                                 SourceLocation RParenLoc,
                                 Expr *Op);
  CastKind PrepareScalarCast(ExprResult &src, QualType destType);

  /// \brief Build an altivec or OpenCL literal.
  ExprResult BuildVectorLiteral(SourceLocation LParenLoc,
                                SourceLocation RParenLoc, Expr *E,
                                TypeSourceInfo *TInfo);

  ExprResult MaybeConvertParenListExprToParenExpr(Scope *S, Expr *ME);

  ExprResult ActOnCompoundLiteral(SourceLocation LParenLoc,
                                  ParsedType Ty,
                                  SourceLocation RParenLoc,
                                  Expr *InitExpr);

  ExprResult BuildCompoundLiteralExpr(SourceLocation LParenLoc,
                                      TypeSourceInfo *TInfo,
                                      SourceLocation RParenLoc,
                                      Expr *LiteralExpr);

  ExprResult ActOnInitList(SourceLocation LBraceLoc,
                           MultiExprArg InitArgList,
                           SourceLocation RBraceLoc);

  ExprResult ActOnDesignatedInitializer(Designation &Desig,
                                        SourceLocation Loc,
                                        bool GNUSyntax,
                                        ExprResult Init);

  ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc,
                        tok::TokenKind Kind, Expr *LHSExpr, Expr *RHSExpr);
  ExprResult BuildBinOp(Scope *S, SourceLocation OpLoc,
                        BinaryOperatorKind Opc, Expr *LHSExpr, Expr *RHSExpr);
  ExprResult CreateBuiltinBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
                                Expr *LHSExpr, Expr *RHSExpr);

  /// ActOnConditionalOp - Parse a ?: operation.  Note that 'LHS' may be null
  /// in the case of a the GNU conditional expr extension.
  ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,
                                SourceLocation ColonLoc,
                                Expr *CondExpr, Expr *LHSExpr, Expr *RHSExpr);

  /// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
  ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
                            LabelDecl *TheDecl);

  void ActOnStartStmtExpr();
  ExprResult ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
                           SourceLocation RPLoc); // "({..})"
  void ActOnStmtExprError();

  // __builtin_offsetof(type, identifier(.identifier|[expr])*)
  struct OffsetOfComponent {
    SourceLocation LocStart, LocEnd;
    bool isBrackets;  // true if [expr], false if .ident
    union {
      IdentifierInfo *IdentInfo;
      Expr *E;
    } U;
  };

  /// __builtin_offsetof(type, a.b[123][456].c)
  ExprResult BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
                                  TypeSourceInfo *TInfo,
                                  OffsetOfComponent *CompPtr,
                                  unsigned NumComponents,
                                  SourceLocation RParenLoc);
  ExprResult ActOnBuiltinOffsetOf(Scope *S,
                                  SourceLocation BuiltinLoc,
                                  SourceLocation TypeLoc,
                                  ParsedType ParsedArgTy,
                                  OffsetOfComponent *CompPtr,
                                  unsigned NumComponents,
                                  SourceLocation RParenLoc);

  // __builtin_choose_expr(constExpr, expr1, expr2)
  ExprResult ActOnChooseExpr(SourceLocation BuiltinLoc,
                             Expr *CondExpr, Expr *LHSExpr,
                             Expr *RHSExpr, SourceLocation RPLoc);

  // __builtin_va_arg(expr, type)
  ExprResult ActOnVAArg(SourceLocation BuiltinLoc, Expr *E, ParsedType Ty,
                        SourceLocation RPLoc);
  ExprResult BuildVAArgExpr(SourceLocation BuiltinLoc, Expr *E,
                            TypeSourceInfo *TInfo, SourceLocation RPLoc);

  // __null
  ExprResult ActOnGNUNullExpr(SourceLocation TokenLoc);

  bool CheckCaseExpression(Expr *E);

  /// \brief Describes the result of an "if-exists" condition check.
  enum IfExistsResult {
    /// \brief The symbol exists.
    IER_Exists,

    /// \brief The symbol does not exist.
    IER_DoesNotExist,

    /// \brief The name is a dependent name, so the results will differ
    /// from one instantiation to the next.
    IER_Dependent,

    /// \brief An error occurred.
    IER_Error
  };

  IfExistsResult
  CheckMicrosoftIfExistsSymbol(Scope *S, CXXScopeSpec &SS,
                               const DeclarationNameInfo &TargetNameInfo);

  IfExistsResult
  CheckMicrosoftIfExistsSymbol(Scope *S, SourceLocation KeywordLoc,
                               bool IsIfExists, CXXScopeSpec &SS,
                               UnqualifiedId &Name);

  StmtResult BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
                                        bool IsIfExists,
                                        NestedNameSpecifierLoc QualifierLoc,
                                        DeclarationNameInfo NameInfo,
                                        Stmt *Nested);
  StmtResult ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
                                        bool IsIfExists,
                                        CXXScopeSpec &SS, UnqualifiedId &Name,
                                        Stmt *Nested);

  //===------------------------- "Block" Extension ------------------------===//

  /// ActOnBlockStart - This callback is invoked when a block literal is
  /// started.
  void ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope);

  /// ActOnBlockArguments - This callback allows processing of block arguments.
  /// If there are no arguments, this is still invoked.
  void ActOnBlockArguments(Declarator &ParamInfo, Scope *CurScope);

  /// ActOnBlockError - If there is an error parsing a block, this callback
  /// is invoked to pop the information about the block from the action impl.
  void ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope);

  /// ActOnBlockStmtExpr - This is called when the body of a block statement
  /// literal was successfully completed.  ^(int x){...}
  ExprResult ActOnBlockStmtExpr(SourceLocation CaretLoc, Stmt *Body,
                                Scope *CurScope);

  //===---------------------------- OpenCL Features -----------------------===//

  /// __builtin_astype(...)
  ExprResult ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
                             SourceLocation BuiltinLoc,
                             SourceLocation RParenLoc);

  //===---------------------------- C++ Features --------------------------===//

  // Act on C++ namespaces
  Decl *ActOnStartNamespaceDef(Scope *S, SourceLocation InlineLoc,
                               SourceLocation NamespaceLoc,
                               SourceLocation IdentLoc,
                               IdentifierInfo *Ident,
                               SourceLocation LBrace,
                               AttributeList *AttrList);
  void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);

  NamespaceDecl *getStdNamespace() const;
  NamespaceDecl *getOrCreateStdNamespace();

  CXXRecordDecl *getStdBadAlloc() const;

  /// \brief Tests whether Ty is an instance of std::initializer_list and, if
  /// it is and Element is not NULL, assigns the element type to Element.
  bool isStdInitializerList(QualType Ty, QualType *Element);

  /// \brief Looks for the std::initializer_list template and instantiates it
  /// with Element, or emits an error if it's not found.
  ///
  /// \returns The instantiated template, or null on error.
  QualType BuildStdInitializerList(QualType Element, SourceLocation Loc);

  /// \brief Determine whether Ctor is an initializer-list constructor, as
  /// defined in [dcl.init.list]p2.
  bool isInitListConstructor(const CXXConstructorDecl *Ctor);

  Decl *ActOnUsingDirective(Scope *CurScope,
                            SourceLocation UsingLoc,
                            SourceLocation NamespcLoc,
                            CXXScopeSpec &SS,
                            SourceLocation IdentLoc,
                            IdentifierInfo *NamespcName,
                            AttributeList *AttrList);

  void PushUsingDirective(Scope *S, UsingDirectiveDecl *UDir);

  Decl *ActOnNamespaceAliasDef(Scope *CurScope,
                               SourceLocation NamespaceLoc,
                               SourceLocation AliasLoc,
                               IdentifierInfo *Alias,
                               CXXScopeSpec &SS,
                               SourceLocation IdentLoc,
                               IdentifierInfo *Ident);

  void HideUsingShadowDecl(Scope *S, UsingShadowDecl *Shadow);
  bool CheckUsingShadowDecl(UsingDecl *UD, NamedDecl *Target,
                            const LookupResult &PreviousDecls);
  UsingShadowDecl *BuildUsingShadowDecl(Scope *S, UsingDecl *UD,
                                        NamedDecl *Target);

  bool CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
                                   bool isTypeName,
                                   const CXXScopeSpec &SS,
                                   SourceLocation NameLoc,
                                   const LookupResult &Previous);
  bool CheckUsingDeclQualifier(SourceLocation UsingLoc,
                               const CXXScopeSpec &SS,
                               SourceLocation NameLoc);

  NamedDecl *BuildUsingDeclaration(Scope *S, AccessSpecifier AS,
                                   SourceLocation UsingLoc,
                                   CXXScopeSpec &SS,
                                   const DeclarationNameInfo &NameInfo,
                                   AttributeList *AttrList,
                                   bool IsInstantiation,
                                   bool IsTypeName,
                                   SourceLocation TypenameLoc);

  bool CheckInheritingConstructorUsingDecl(UsingDecl *UD);

  Decl *ActOnUsingDeclaration(Scope *CurScope,
                              AccessSpecifier AS,
                              bool HasUsingKeyword,
                              SourceLocation UsingLoc,
                              CXXScopeSpec &SS,
                              UnqualifiedId &Name,
                              AttributeList *AttrList,
                              bool IsTypeName,
                              SourceLocation TypenameLoc);
  Decl *ActOnAliasDeclaration(Scope *CurScope,
                              AccessSpecifier AS,
                              MultiTemplateParamsArg TemplateParams,
                              SourceLocation UsingLoc,
                              UnqualifiedId &Name,
                              TypeResult Type);

  /// InitializeVarWithConstructor - Creates an CXXConstructExpr
  /// and sets it as the initializer for the the passed in VarDecl.
  bool InitializeVarWithConstructor(VarDecl *VD,
                                    CXXConstructorDecl *Constructor,
                                    MultiExprArg Exprs,
                                    bool HadMultipleCandidates);

  /// BuildCXXConstructExpr - Creates a complete call to a constructor,
  /// including handling of its default argument expressions.
  ///
  /// \param ConstructKind - a CXXConstructExpr::ConstructionKind
  ExprResult
  BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                        CXXConstructorDecl *Constructor, MultiExprArg Exprs,
                        bool HadMultipleCandidates, bool RequiresZeroInit,
                        unsigned ConstructKind, SourceRange ParenRange);

  // FIXME: Can re remove this and have the above BuildCXXConstructExpr check if
  // the constructor can be elidable?
  ExprResult
  BuildCXXConstructExpr(SourceLocation ConstructLoc, QualType DeclInitType,
                        CXXConstructorDecl *Constructor, bool Elidable,
                        MultiExprArg Exprs, bool HadMultipleCandidates,
                        bool RequiresZeroInit, unsigned ConstructKind,
                        SourceRange ParenRange);

  /// BuildCXXDefaultArgExpr - Creates a CXXDefaultArgExpr, instantiating
  /// the default expr if needed.
  ExprResult BuildCXXDefaultArgExpr(SourceLocation CallLoc,
                                    FunctionDecl *FD,
                                    ParmVarDecl *Param);

  /// FinalizeVarWithDestructor - Prepare for calling destructor on the
  /// constructed variable.
  void FinalizeVarWithDestructor(VarDecl *VD, const RecordType *DeclInitType);

  /// \brief Helper class that collects exception specifications for
  /// implicitly-declared special member functions.
  class ImplicitExceptionSpecification {
    // Pointer to allow copying
    Sema *Self;
    // We order exception specifications thus:
    // noexcept is the most restrictive, but is only used in C++0x.
    // throw() comes next.
    // Then a throw(collected exceptions)
    // Finally no specification.
    // throw(...) is used instead if any called function uses it.
    //
    // If this exception specification cannot be known yet (for instance,
    // because this is the exception specification for a defaulted default
    // constructor and we haven't finished parsing the deferred parts of the
    // class yet), the C++0x standard does not specify how to behave. We
    // record this as an 'unknown' exception specification, which overrules
    // any other specification (even 'none', to keep this rule simple).
    ExceptionSpecificationType ComputedEST;
    llvm::SmallPtrSet<CanQualType, 4> ExceptionsSeen;
    SmallVector<QualType, 4> Exceptions;

    void ClearExceptions() {
      ExceptionsSeen.clear();
      Exceptions.clear();
    }

  public:
    explicit ImplicitExceptionSpecification(Sema &Self)
      : Self(&Self), ComputedEST(EST_BasicNoexcept) {
      if (!Self.Context.getLangOpts().CPlusPlus0x)
        ComputedEST = EST_DynamicNone;
    }

    /// \brief Get the computed exception specification type.
    ExceptionSpecificationType getExceptionSpecType() const {
      assert(ComputedEST != EST_ComputedNoexcept &&
             "noexcept(expr) should not be a possible result");
      return ComputedEST;
    }

    /// \brief The number of exceptions in the exception specification.
    unsigned size() const { return Exceptions.size(); }

    /// \brief The set of exceptions in the exception specification.
    const QualType *data() const { return Exceptions.data(); }

    /// \brief Integrate another called method into the collected data.
    void CalledDecl(SourceLocation CallLoc, CXXMethodDecl *Method);

    /// \brief Integrate an invoked expression into the collected data.
    void CalledExpr(Expr *E);

    /// \brief Specify that the exception specification can't be detemined yet.
    void SetDelayed() {
      ClearExceptions();
      ComputedEST = EST_Delayed;
    }

    FunctionProtoType::ExtProtoInfo getEPI() const {
      FunctionProtoType::ExtProtoInfo EPI;
      EPI.ExceptionSpecType = getExceptionSpecType();
      EPI.NumExceptions = size();
      EPI.Exceptions = data();
      return EPI;
    }
  };

  /// \brief Determine what sort of exception specification a defaulted
  /// copy constructor of a class will have.
  ImplicitExceptionSpecification
  ComputeDefaultedDefaultCtorExceptionSpec(CXXRecordDecl *ClassDecl);

  /// \brief Determine what sort of exception specification a defaulted
  /// default constructor of a class will have, and whether the parameter
  /// will be const.
  std::pair<ImplicitExceptionSpecification, bool>
  ComputeDefaultedCopyCtorExceptionSpecAndConst(CXXRecordDecl *ClassDecl);

  /// \brief Determine what sort of exception specification a defautled
  /// copy assignment operator of a class will have, and whether the
  /// parameter will be const.
  std::pair<ImplicitExceptionSpecification, bool>
  ComputeDefaultedCopyAssignmentExceptionSpecAndConst(CXXRecordDecl *ClassDecl);

  /// \brief Determine what sort of exception specification a defaulted move
  /// constructor of a class will have.
  ImplicitExceptionSpecification
  ComputeDefaultedMoveCtorExceptionSpec(CXXRecordDecl *ClassDecl);

  /// \brief Determine what sort of exception specification a defaulted move
  /// assignment operator of a class will have.
  ImplicitExceptionSpecification
  ComputeDefaultedMoveAssignmentExceptionSpec(CXXRecordDecl *ClassDecl);

  /// \brief Determine what sort of exception specification a defaulted
  /// destructor of a class will have.
  ImplicitExceptionSpecification
  ComputeDefaultedDtorExceptionSpec(CXXRecordDecl *ClassDecl);

  /// \brief Check the given exception-specification and update the
  /// extended prototype information with the results.
  void checkExceptionSpecification(ExceptionSpecificationType EST,
                                   ArrayRef<ParsedType> DynamicExceptions,
                                   ArrayRef<SourceRange> DynamicExceptionRanges,
                                   Expr *NoexceptExpr,
                                   llvm::SmallVectorImpl<QualType> &Exceptions,
                                   FunctionProtoType::ExtProtoInfo &EPI);

  /// \brief Add an exception-specification to the given member function
  /// (or member function template). The exception-specification was parsed
  /// after the method itself was declared.
  void actOnDelayedExceptionSpecification(Decl *Method,
         ExceptionSpecificationType EST,
         SourceRange SpecificationRange,
         ArrayRef<ParsedType> DynamicExceptions,
         ArrayRef<SourceRange> DynamicExceptionRanges,
         Expr *NoexceptExpr);

  /// \brief Determine if a special member function should have a deleted
  /// definition when it is defaulted.
  bool ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMember CSM,
                                 bool Diagnose = false);

  /// \brief Declare the implicit default constructor for the given class.
  ///
  /// \param ClassDecl The class declaration into which the implicit
  /// default constructor will be added.
  ///
  /// \returns The implicitly-declared default constructor.
  CXXConstructorDecl *DeclareImplicitDefaultConstructor(
                                                     CXXRecordDecl *ClassDecl);

  /// DefineImplicitDefaultConstructor - Checks for feasibility of
  /// defining this constructor as the default constructor.
  void DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
                                        CXXConstructorDecl *Constructor);

  /// \brief Declare the implicit destructor for the given class.
  ///
  /// \param ClassDecl The class declaration into which the implicit
  /// destructor will be added.
  ///
  /// \returns The implicitly-declared destructor.
  CXXDestructorDecl *DeclareImplicitDestructor(CXXRecordDecl *ClassDecl);

  /// DefineImplicitDestructor - Checks for feasibility of
  /// defining this destructor as the default destructor.
  void DefineImplicitDestructor(SourceLocation CurrentLocation,
                                CXXDestructorDecl *Destructor);

  /// \brief Build an exception spec for destructors that don't have one.
  ///
  /// C++11 says that user-defined destructors with no exception spec get one
  /// that looks as if the destructor was implicitly declared.
  void AdjustDestructorExceptionSpec(CXXRecordDecl *ClassDecl,
                                     CXXDestructorDecl *Destructor);

  /// \brief Declare all inherited constructors for the given class.
  ///
  /// \param ClassDecl The class declaration into which the inherited
  /// constructors will be added.
  void DeclareInheritedConstructors(CXXRecordDecl *ClassDecl);

  /// \brief Declare the implicit copy constructor for the given class.
  ///
  /// \param ClassDecl The class declaration into which the implicit
  /// copy constructor will be added.
  ///
  /// \returns The implicitly-declared copy constructor.
  CXXConstructorDecl *DeclareImplicitCopyConstructor(CXXRecordDecl *ClassDecl);

  /// DefineImplicitCopyConstructor - Checks for feasibility of
  /// defining this constructor as the copy constructor.
  void DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
                                     CXXConstructorDecl *Constructor);

  /// \brief Declare the implicit move constructor for the given class.
  ///
  /// \param ClassDecl The Class declaration into which the implicit
  /// move constructor will be added.
  ///
  /// \returns The implicitly-declared move constructor, or NULL if it wasn't
  /// declared.
  CXXConstructorDecl *DeclareImplicitMoveConstructor(CXXRecordDecl *ClassDecl);

  /// DefineImplicitMoveConstructor - Checks for feasibility of
  /// defining this constructor as the move constructor.
  void DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
                                     CXXConstructorDecl *Constructor);

  /// \brief Declare the implicit copy assignment operator for the given class.
  ///
  /// \param ClassDecl The class declaration into which the implicit
  /// copy assignment operator will be added.
  ///
  /// \returns The implicitly-declared copy assignment operator.
  CXXMethodDecl *DeclareImplicitCopyAssignment(CXXRecordDecl *ClassDecl);

  /// \brief Defines an implicitly-declared copy assignment operator.
  void DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
                                    CXXMethodDecl *MethodDecl);

  /// \brief Declare the implicit move assignment operator for the given class.
  ///
  /// \param ClassDecl The Class declaration into which the implicit
  /// move assignment operator will be added.
  ///
  /// \returns The implicitly-declared move assignment operator, or NULL if it
  /// wasn't declared.
  CXXMethodDecl *DeclareImplicitMoveAssignment(CXXRecordDecl *ClassDecl);

  /// \brief Defines an implicitly-declared move assignment operator.
  void DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
                                    CXXMethodDecl *MethodDecl);

  /// \brief Force the declaration of any implicitly-declared members of this
  /// class.
  void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);

  /// \brief Determine whether the given function is an implicitly-deleted
  /// special member function.
  bool isImplicitlyDeleted(FunctionDecl *FD);

  /// \brief Check whether 'this' shows up in the type of a static member
  /// function after the (naturally empty) cv-qualifier-seq would be.
  ///
  /// \returns true if an error occurred.
  bool checkThisInStaticMemberFunctionType(CXXMethodDecl *Method);

  /// \brief Whether this' shows up in the exception specification of a static
  /// member function.
  bool checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method);

  /// \brief Check whether 'this' shows up in the attributes of the given
  /// static member function.
  ///
  /// \returns true if an error occurred.
  bool checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method);

  /// MaybeBindToTemporary - If the passed in expression has a record type with
  /// a non-trivial destructor, this will return CXXBindTemporaryExpr. Otherwise
  /// it simply returns the passed in expression.
  ExprResult MaybeBindToTemporary(Expr *E);

  bool CompleteConstructorCall(CXXConstructorDecl *Constructor,
                               MultiExprArg ArgsPtr,
                               SourceLocation Loc,
                               ASTOwningVector<Expr*> &ConvertedArgs,
                               bool AllowExplicit = false);

  ParsedType getDestructorName(SourceLocation TildeLoc,
                               IdentifierInfo &II, SourceLocation NameLoc,
                               Scope *S, CXXScopeSpec &SS,
                               ParsedType ObjectType,
                               bool EnteringContext);

  ParsedType getDestructorType(const DeclSpec& DS, ParsedType ObjectType);

  // Checks that reinterpret casts don't have undefined behavior.
  void CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
                                      bool IsDereference, SourceRange Range);

  /// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
  ExprResult ActOnCXXNamedCast(SourceLocation OpLoc,
                               tok::TokenKind Kind,
                               SourceLocation LAngleBracketLoc,
                               Declarator &D,
                               SourceLocation RAngleBracketLoc,
                               SourceLocation LParenLoc,
                               Expr *E,
                               SourceLocation RParenLoc);

  ExprResult BuildCXXNamedCast(SourceLocation OpLoc,
                               tok::TokenKind Kind,
                               TypeSourceInfo *Ty,
                               Expr *E,
                               SourceRange AngleBrackets,
                               SourceRange Parens);

  ExprResult BuildCXXTypeId(QualType TypeInfoType,
                            SourceLocation TypeidLoc,
                            TypeSourceInfo *Operand,
                            SourceLocation RParenLoc);
  ExprResult BuildCXXTypeId(QualType TypeInfoType,
                            SourceLocation TypeidLoc,
                            Expr *Operand,
                            SourceLocation RParenLoc);

  /// ActOnCXXTypeid - Parse typeid( something ).
  ExprResult ActOnCXXTypeid(SourceLocation OpLoc,
                            SourceLocation LParenLoc, bool isType,
                            void *TyOrExpr,
                            SourceLocation RParenLoc);

  ExprResult BuildCXXUuidof(QualType TypeInfoType,
                            SourceLocation TypeidLoc,
                            TypeSourceInfo *Operand,
                            SourceLocation RParenLoc);
  ExprResult BuildCXXUuidof(QualType TypeInfoType,
                            SourceLocation TypeidLoc,
                            Expr *Operand,
                            SourceLocation RParenLoc);

  /// ActOnCXXUuidof - Parse __uuidof( something ).
  ExprResult ActOnCXXUuidof(SourceLocation OpLoc,
                            SourceLocation LParenLoc, bool isType,
                            void *TyOrExpr,
                            SourceLocation RParenLoc);


  //// ActOnCXXThis -  Parse 'this' pointer.
  ExprResult ActOnCXXThis(SourceLocation loc);

  /// \brief Try to retrieve the type of the 'this' pointer.
  ///
  /// \param Capture If true, capture 'this' in this context.
  ///
  /// \returns The type of 'this', if possible. Otherwise, returns a NULL type.
  QualType getCurrentThisType();

  /// \brief When non-NULL, the C++ 'this' expression is allowed despite the
  /// current context not being a non-static member function. In such cases,
  /// this provides the type used for 'this'.
  QualType CXXThisTypeOverride;

  /// \brief RAII object used to temporarily allow the C++ 'this' expression
  /// to be used, with the given qualifiers on the current class type.
  class CXXThisScopeRAII {
    Sema &S;
    QualType OldCXXThisTypeOverride;
    bool Enabled;

  public:
    /// \brief Introduce a new scope where 'this' may be allowed (when enabled),
    /// using the given declaration (which is either a class template or a
    /// class) along with the given qualifiers.
    /// along with the qualifiers placed on '*this'.
    CXXThisScopeRAII(Sema &S, Decl *ContextDecl, unsigned CXXThisTypeQuals,
                     bool Enabled = true);

    ~CXXThisScopeRAII();
  };

  /// \brief Make sure the value of 'this' is actually available in the current
  /// context, if it is a potentially evaluated context.
  ///
  /// \param Loc The location at which the capture of 'this' occurs.
  ///
  /// \param Explicit Whether 'this' is explicitly captured in a lambda
  /// capture list.
  void CheckCXXThisCapture(SourceLocation Loc, bool Explicit = false);

  /// \brief Determine whether the given type is the type of *this that is used
  /// outside of the body of a member function for a type that is currently
  /// being defined.
  bool isThisOutsideMemberFunctionBody(QualType BaseType);

  /// ActOnCXXBoolLiteral - Parse {true,false} literals.
  ExprResult ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);


  /// ActOnObjCBoolLiteral - Parse {__objc_yes,__objc_no} literals.
  ExprResult ActOnObjCBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);

  /// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
  ExprResult ActOnCXXNullPtrLiteral(SourceLocation Loc);

  //// ActOnCXXThrow -  Parse throw expressions.
  ExprResult ActOnCXXThrow(Scope *S, SourceLocation OpLoc, Expr *expr);
  ExprResult BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
                           bool IsThrownVarInScope);
  ExprResult CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *E,
                                  bool IsThrownVarInScope);

  /// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
  /// Can be interpreted either as function-style casting ("int(x)")
  /// or class type construction ("ClassType(x,y,z)")
  /// or creation of a value-initialized type ("int()").
  ExprResult ActOnCXXTypeConstructExpr(ParsedType TypeRep,
                                       SourceLocation LParenLoc,
                                       MultiExprArg Exprs,
                                       SourceLocation RParenLoc);

  ExprResult BuildCXXTypeConstructExpr(TypeSourceInfo *Type,
                                       SourceLocation LParenLoc,
                                       MultiExprArg Exprs,
                                       SourceLocation RParenLoc);

  /// ActOnCXXNew - Parsed a C++ 'new' expression.
  ExprResult ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
                         SourceLocation PlacementLParen,
                         MultiExprArg PlacementArgs,
                         SourceLocation PlacementRParen,
                         SourceRange TypeIdParens, Declarator &D,
                         Expr *Initializer);
  ExprResult BuildCXXNew(SourceLocation StartLoc, bool UseGlobal,
                         SourceLocation PlacementLParen,
                         MultiExprArg PlacementArgs,
                         SourceLocation PlacementRParen,
                         SourceRange TypeIdParens,
                         QualType AllocType,
                         TypeSourceInfo *AllocTypeInfo,
                         Expr *ArraySize,
                         SourceRange DirectInitRange,
                         Expr *Initializer,
                         bool TypeMayContainAuto = true);

  bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
                          SourceRange R);
  bool FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
                               bool UseGlobal, QualType AllocType, bool IsArray,
                               Expr **PlaceArgs, unsigned NumPlaceArgs,
                               FunctionDecl *&OperatorNew,
                               FunctionDecl *&OperatorDelete);
  bool FindAllocationOverload(SourceLocation StartLoc, SourceRange Range,
                              DeclarationName Name, Expr** Args,
                              unsigned NumArgs, DeclContext *Ctx,
                              bool AllowMissing, FunctionDecl *&Operator,
                              bool Diagnose = true);
  void DeclareGlobalNewDelete();
  void DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return,
                                       QualType Argument,
                                       bool addMallocAttr = false);

  bool FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
                                DeclarationName Name, FunctionDecl* &Operator,
                                bool Diagnose = true);

  /// ActOnCXXDelete - Parsed a C++ 'delete' expression
  ExprResult ActOnCXXDelete(SourceLocation StartLoc,
                            bool UseGlobal, bool ArrayForm,
                            Expr *Operand);

  DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);
  ExprResult CheckConditionVariable(VarDecl *ConditionVar,
                                    SourceLocation StmtLoc,
                                    bool ConvertToBoolean);

  ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
                               Expr *Operand, SourceLocation RParen);
  ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
                                  SourceLocation RParen);

  /// ActOnUnaryTypeTrait - Parsed one of the unary type trait support
  /// pseudo-functions.
  ExprResult ActOnUnaryTypeTrait(UnaryTypeTrait OTT,
                                 SourceLocation KWLoc,
                                 ParsedType Ty,
                                 SourceLocation RParen);

  ExprResult BuildUnaryTypeTrait(UnaryTypeTrait OTT,
                                 SourceLocation KWLoc,
                                 TypeSourceInfo *T,
                                 SourceLocation RParen);

  /// ActOnBinaryTypeTrait - Parsed one of the bianry type trait support
  /// pseudo-functions.
  ExprResult ActOnBinaryTypeTrait(BinaryTypeTrait OTT,
                                  SourceLocation KWLoc,
                                  ParsedType LhsTy,
                                  ParsedType RhsTy,
                                  SourceLocation RParen);

  ExprResult BuildBinaryTypeTrait(BinaryTypeTrait BTT,
                                  SourceLocation KWLoc,
                                  TypeSourceInfo *LhsT,
                                  TypeSourceInfo *RhsT,
                                  SourceLocation RParen);

  /// \brief Parsed one of the type trait support pseudo-functions.
  ExprResult ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                            ArrayRef<ParsedType> Args,
                            SourceLocation RParenLoc);
  ExprResult BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                            ArrayRef<TypeSourceInfo *> Args,
                            SourceLocation RParenLoc);

  /// ActOnArrayTypeTrait - Parsed one of the bianry type trait support
  /// pseudo-functions.
  ExprResult ActOnArrayTypeTrait(ArrayTypeTrait ATT,
                                 SourceLocation KWLoc,
                                 ParsedType LhsTy,
                                 Expr *DimExpr,
                                 SourceLocation RParen);

  ExprResult BuildArrayTypeTrait(ArrayTypeTrait ATT,
                                 SourceLocation KWLoc,
                                 TypeSourceInfo *TSInfo,
                                 Expr *DimExpr,
                                 SourceLocation RParen);

  /// ActOnExpressionTrait - Parsed one of the unary type trait support
  /// pseudo-functions.
  ExprResult ActOnExpressionTrait(ExpressionTrait OET,
                                  SourceLocation KWLoc,
                                  Expr *Queried,
                                  SourceLocation RParen);

  ExprResult BuildExpressionTrait(ExpressionTrait OET,
                                  SourceLocation KWLoc,
                                  Expr *Queried,
                                  SourceLocation RParen);

  ExprResult ActOnStartCXXMemberReference(Scope *S,
                                          Expr *Base,
                                          SourceLocation OpLoc,
                                          tok::TokenKind OpKind,
                                          ParsedType &ObjectType,
                                          bool &MayBePseudoDestructor);

  ExprResult DiagnoseDtorReference(SourceLocation NameLoc, Expr *MemExpr);

  ExprResult BuildPseudoDestructorExpr(Expr *Base,
                                       SourceLocation OpLoc,
                                       tok::TokenKind OpKind,
                                       const CXXScopeSpec &SS,
                                       TypeSourceInfo *ScopeType,
                                       SourceLocation CCLoc,
                                       SourceLocation TildeLoc,
                                     PseudoDestructorTypeStorage DestroyedType,
                                       bool HasTrailingLParen);

  ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                       SourceLocation OpLoc,
                                       tok::TokenKind OpKind,
                                       CXXScopeSpec &SS,
                                       UnqualifiedId &FirstTypeName,
                                       SourceLocation CCLoc,
                                       SourceLocation TildeLoc,
                                       UnqualifiedId &SecondTypeName,
                                       bool HasTrailingLParen);

  ExprResult ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                       SourceLocation OpLoc,
                                       tok::TokenKind OpKind,
                                       SourceLocation TildeLoc,
                                       const DeclSpec& DS,
                                       bool HasTrailingLParen);

  /// MaybeCreateExprWithCleanups - If the current full-expression
  /// requires any cleanups, surround it with a ExprWithCleanups node.
  /// Otherwise, just returns the passed-in expression.
  Expr *MaybeCreateExprWithCleanups(Expr *SubExpr);
  Stmt *MaybeCreateStmtWithCleanups(Stmt *SubStmt);
  ExprResult MaybeCreateExprWithCleanups(ExprResult SubExpr);

  ExprResult ActOnFinishFullExpr(Expr *Expr);
  StmtResult ActOnFinishFullStmt(Stmt *Stmt);

  // Marks SS invalid if it represents an incomplete type.
  bool RequireCompleteDeclContext(CXXScopeSpec &SS, DeclContext *DC);

  DeclContext *computeDeclContext(QualType T);
  DeclContext *computeDeclContext(const CXXScopeSpec &SS,
                                  bool EnteringContext = false);
  bool isDependentScopeSpecifier(const CXXScopeSpec &SS);
  CXXRecordDecl *getCurrentInstantiationOf(NestedNameSpecifier *NNS);
  bool isUnknownSpecialization(const CXXScopeSpec &SS);

  /// \brief The parser has parsed a global nested-name-specifier '::'.
  ///
  /// \param S The scope in which this nested-name-specifier occurs.
  ///
  /// \param CCLoc The location of the '::'.
  ///
  /// \param SS The nested-name-specifier, which will be updated in-place
  /// to reflect the parsed nested-name-specifier.
  ///
  /// \returns true if an error occurred, false otherwise.
  bool ActOnCXXGlobalScopeSpecifier(Scope *S, SourceLocation CCLoc,
                                    CXXScopeSpec &SS);

  bool isAcceptableNestedNameSpecifier(NamedDecl *SD);
  NamedDecl *FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS);

  bool isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
                                    SourceLocation IdLoc,
                                    IdentifierInfo &II,
                                    ParsedType ObjectType);

  bool BuildCXXNestedNameSpecifier(Scope *S,
                                   IdentifierInfo &Identifier,
                                   SourceLocation IdentifierLoc,
                                   SourceLocation CCLoc,
                                   QualType ObjectType,
                                   bool EnteringContext,
                                   CXXScopeSpec &SS,
                                   NamedDecl *ScopeLookupResult,
                                   bool ErrorRecoveryLookup);

  /// \brief The parser has parsed a nested-name-specifier 'identifier::'.
  ///
  /// \param S The scope in which this nested-name-specifier occurs.
  ///
  /// \param Identifier The identifier preceding the '::'.
  ///
  /// \param IdentifierLoc The location of the identifier.
  ///
  /// \param CCLoc The location of the '::'.
  ///
  /// \param ObjectType The type of the object, if we're parsing
  /// nested-name-specifier in a member access expression.
  ///
  /// \param EnteringContext Whether we're entering the context nominated by
  /// this nested-name-specifier.
  ///
  /// \param SS The nested-name-specifier, which is both an input
  /// parameter (the nested-name-specifier before this type) and an
  /// output parameter (containing the full nested-name-specifier,
  /// including this new type).
  ///
  /// \returns true if an error occurred, false otherwise.
  bool ActOnCXXNestedNameSpecifier(Scope *S,
                                   IdentifierInfo &Identifier,
                                   SourceLocation IdentifierLoc,
                                   SourceLocation CCLoc,
                                   ParsedType ObjectType,
                                   bool EnteringContext,
                                   CXXScopeSpec &SS);

  ExprResult ActOnDecltypeExpression(Expr *E);

  bool ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
                                           const DeclSpec &DS,
                                           SourceLocation ColonColonLoc);

  bool IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
                                 IdentifierInfo &Identifier,
                                 SourceLocation IdentifierLoc,
                                 SourceLocation ColonLoc,
                                 ParsedType ObjectType,
                                 bool EnteringContext);

  /// \brief The parser has parsed a nested-name-specifier
  /// 'template[opt] template-name < template-args >::'.
  ///
  /// \param S The scope in which this nested-name-specifier occurs.
  ///
  /// \param SS The nested-name-specifier, which is both an input
  /// parameter (the nested-name-specifier before this type) and an
  /// output parameter (containing the full nested-name-specifier,
  /// including this new type).
  ///
  /// \param TemplateKWLoc the location of the 'template' keyword, if any.
  /// \param TemplateName The template name.
  /// \param TemplateNameLoc The location of the template name.
  /// \param LAngleLoc The location of the opening angle bracket  ('<').
  /// \param TemplateArgs The template arguments.
  /// \param RAngleLoc The location of the closing angle bracket  ('>').
  /// \param CCLoc The location of the '::'.
  ///
  /// \param EnteringContext Whether we're entering the context of the
  /// nested-name-specifier.
  ///
  ///
  /// \returns true if an error occurred, false otherwise.
  bool ActOnCXXNestedNameSpecifier(Scope *S,
                                   CXXScopeSpec &SS,
                                   SourceLocation TemplateKWLoc,
                                   TemplateTy Template,
                                   SourceLocation TemplateNameLoc,
                                   SourceLocation LAngleLoc,
                                   ASTTemplateArgsPtr TemplateArgs,
                                   SourceLocation RAngleLoc,
                                   SourceLocation CCLoc,
                                   bool EnteringContext);

  /// \brief Given a C++ nested-name-specifier, produce an annotation value
  /// that the parser can use later to reconstruct the given
  /// nested-name-specifier.
  ///
  /// \param SS A nested-name-specifier.
  ///
  /// \returns A pointer containing all of the information in the
  /// nested-name-specifier \p SS.
  void *SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS);

  /// \brief Given an annotation pointer for a nested-name-specifier, restore
  /// the nested-name-specifier structure.
  ///
  /// \param Annotation The annotation pointer, produced by
  /// \c SaveNestedNameSpecifierAnnotation().
  ///
  /// \param AnnotationRange The source range corresponding to the annotation.
  ///
  /// \param SS The nested-name-specifier that will be updated with the contents
  /// of the annotation pointer.
  void RestoreNestedNameSpecifierAnnotation(void *Annotation,
                                            SourceRange AnnotationRange,
                                            CXXScopeSpec &SS);

  bool ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

  /// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
  /// scope or nested-name-specifier) is parsed, part of a declarator-id.
  /// After this method is called, according to [C++ 3.4.3p3], names should be
  /// looked up in the declarator-id's scope, until the declarator is parsed and
  /// ActOnCXXExitDeclaratorScope is called.
  /// The 'SS' should be a non-empty valid CXXScopeSpec.
  bool ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS);

  /// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
  /// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
  /// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
  /// Used to indicate that names should revert to being looked up in the
  /// defining scope.
  void ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS);

  /// ActOnCXXEnterDeclInitializer - Invoked when we are about to parse an
  /// initializer for the declaration 'Dcl'.
  /// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
  /// static data member of class X, names should be looked up in the scope of
  /// class X.
  void ActOnCXXEnterDeclInitializer(Scope *S, Decl *Dcl);

  /// ActOnCXXExitDeclInitializer - Invoked after we are finished parsing an
  /// initializer for the declaration 'Dcl'.
  void ActOnCXXExitDeclInitializer(Scope *S, Decl *Dcl);