xref: /external/clang/lib/Sema/SemaCodeComplete.cpp

//===---------------- SemaCodeComplete.cpp - Code Completion ----*- 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 code-completion semantic actions.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/CodeCompleteConsumer.h"
#include "clang/Sema/ExternalSemaSource.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Overload.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Twine.h"
#include <list>
#include <map>
#include <vector>

using namespace clang;
using namespace sema;

namespace {
  /// \brief A container of code-completion results.
  class ResultBuilder {
  public:
    /// \brief The type of a name-lookup filter, which can be provided to the
    /// name-lookup routines to specify which declarations should be included in
    /// the result set (when it returns true) and which declarations should be
    /// filtered out (returns false).
    typedef bool (ResultBuilder::*LookupFilter)(const NamedDecl *) const;

    typedef CodeCompletionResult Result;

  private:
    /// \brief The actual results we have found.
    std::vector<Result> Results;

    /// \brief A record of all of the declarations we have found and placed
    /// into the result set, used to ensure that no declaration ever gets into
    /// the result set twice.
    llvm::SmallPtrSet<const Decl*, 16> AllDeclsFound;

    typedef std::pair<const NamedDecl *, unsigned> DeclIndexPair;

    /// \brief An entry in the shadow map, which is optimized to store
    /// a single (declaration, index) mapping (the common case) but
    /// can also store a list of (declaration, index) mappings.
    class ShadowMapEntry {
      typedef SmallVector<DeclIndexPair, 4> DeclIndexPairVector;

      /// \brief Contains either the solitary NamedDecl * or a vector
      /// of (declaration, index) pairs.
      llvm::PointerUnion<const NamedDecl *, DeclIndexPairVector*> DeclOrVector;

      /// \brief When the entry contains a single declaration, this is
      /// the index associated with that entry.
      unsigned SingleDeclIndex;

    public:
      ShadowMapEntry() : DeclOrVector(), SingleDeclIndex(0) { }

      void Add(const NamedDecl *ND, unsigned Index) {
        if (DeclOrVector.isNull()) {
          // 0 - > 1 elements: just set the single element information.
          DeclOrVector = ND;
          SingleDeclIndex = Index;
          return;
        }

        if (const NamedDecl *PrevND =
                DeclOrVector.dyn_cast<const NamedDecl *>()) {
          // 1 -> 2 elements: create the vector of results and push in the
          // existing declaration.
          DeclIndexPairVector *Vec = new DeclIndexPairVector;
          Vec->push_back(DeclIndexPair(PrevND, SingleDeclIndex));
          DeclOrVector = Vec;
        }

        // Add the new element to the end of the vector.
        DeclOrVector.get<DeclIndexPairVector*>()->push_back(
                                                    DeclIndexPair(ND, Index));
      }

      void Destroy() {
        if (DeclIndexPairVector *Vec
              = DeclOrVector.dyn_cast<DeclIndexPairVector *>()) {
          delete Vec;
          DeclOrVector = ((NamedDecl *)0);
        }
      }

      // Iteration.
      class iterator;
      iterator begin() const;
      iterator end() const;
    };

    /// \brief A mapping from declaration names to the declarations that have
    /// this name within a particular scope and their index within the list of
    /// results.
    typedef llvm::DenseMap<DeclarationName, ShadowMapEntry> ShadowMap;

    /// \brief The semantic analysis object for which results are being
    /// produced.
    Sema &SemaRef;

    /// \brief The allocator used to allocate new code-completion strings.
    CodeCompletionAllocator &Allocator;

    CodeCompletionTUInfo &CCTUInfo;

    /// \brief If non-NULL, a filter function used to remove any code-completion
    /// results that are not desirable.
    LookupFilter Filter;

    /// \brief Whether we should allow declarations as
    /// nested-name-specifiers that would otherwise be filtered out.
    bool AllowNestedNameSpecifiers;

    /// \brief If set, the type that we would prefer our resulting value
    /// declarations to have.
    ///
    /// Closely matching the preferred type gives a boost to a result's
    /// priority.
    CanQualType PreferredType;

    /// \brief A list of shadow maps, which is used to model name hiding at
    /// different levels of, e.g., the inheritance hierarchy.
    std::list<ShadowMap> ShadowMaps;

    /// \brief If we're potentially referring to a C++ member function, the set
    /// of qualifiers applied to the object type.
    Qualifiers ObjectTypeQualifiers;

    /// \brief Whether the \p ObjectTypeQualifiers field is active.
    bool HasObjectTypeQualifiers;

    /// \brief The selector that we prefer.
    Selector PreferredSelector;

    /// \brief The completion context in which we are gathering results.
    CodeCompletionContext CompletionContext;

    /// \brief If we are in an instance method definition, the \@implementation
    /// object.
    ObjCImplementationDecl *ObjCImplementation;

    void AdjustResultPriorityForDecl(Result &R);

    void MaybeAddConstructorResults(Result R);

  public:
    explicit ResultBuilder(Sema &SemaRef, CodeCompletionAllocator &Allocator,
                           CodeCompletionTUInfo &CCTUInfo,
                           const CodeCompletionContext &CompletionContext,
                           LookupFilter Filter = 0)
      : SemaRef(SemaRef), Allocator(Allocator), CCTUInfo(CCTUInfo),
        Filter(Filter),
        AllowNestedNameSpecifiers(false), HasObjectTypeQualifiers(false),
        CompletionContext(CompletionContext),
        ObjCImplementation(0)
    {
      // If this is an Objective-C instance method definition, dig out the
      // corresponding implementation.
      switch (CompletionContext.getKind()) {
      case CodeCompletionContext::CCC_Expression:
      case CodeCompletionContext::CCC_ObjCMessageReceiver:
      case CodeCompletionContext::CCC_ParenthesizedExpression:
      case CodeCompletionContext::CCC_Statement:
      case CodeCompletionContext::CCC_Recovery:
        if (ObjCMethodDecl *Method = SemaRef.getCurMethodDecl())
          if (Method->isInstanceMethod())
            if (ObjCInterfaceDecl *Interface = Method->getClassInterface())
              ObjCImplementation = Interface->getImplementation();
        break;

      default:
        break;
      }
    }

    /// \brief Determine the priority for a reference to the given declaration.
    unsigned getBasePriority(const NamedDecl *D);

    /// \brief Whether we should include code patterns in the completion
    /// results.
    bool includeCodePatterns() const {
      return SemaRef.CodeCompleter &&
             SemaRef.CodeCompleter->includeCodePatterns();
    }

    /// \brief Set the filter used for code-completion results.
    void setFilter(LookupFilter Filter) {
      this->Filter = Filter;
    }

    Result *data() { return Results.empty()? 0 : &Results.front(); }
    unsigned size() const { return Results.size(); }
    bool empty() const { return Results.empty(); }

    /// \brief Specify the preferred type.
    void setPreferredType(QualType T) {
      PreferredType = SemaRef.Context.getCanonicalType(T);
    }

    /// \brief Set the cv-qualifiers on the object type, for us in filtering
    /// calls to member functions.
    ///
    /// When there are qualifiers in this set, they will be used to filter
    /// out member functions that aren't available (because there will be a
    /// cv-qualifier mismatch) or prefer functions with an exact qualifier
    /// match.
    void setObjectTypeQualifiers(Qualifiers Quals) {
      ObjectTypeQualifiers = Quals;
      HasObjectTypeQualifiers = true;
    }

    /// \brief Set the preferred selector.
    ///
    /// When an Objective-C method declaration result is added, and that
    /// method's selector matches this preferred selector, we give that method
    /// a slight priority boost.
    void setPreferredSelector(Selector Sel) {
      PreferredSelector = Sel;
    }

    /// \brief Retrieve the code-completion context for which results are
    /// being collected.
    const CodeCompletionContext &getCompletionContext() const {
      return CompletionContext;
    }

    /// \brief Specify whether nested-name-specifiers are allowed.
    void allowNestedNameSpecifiers(bool Allow = true) {
      AllowNestedNameSpecifiers = Allow;
    }

    /// \brief Return the semantic analysis object for which we are collecting
    /// code completion results.
    Sema &getSema() const { return SemaRef; }

    /// \brief Retrieve the allocator used to allocate code completion strings.
    CodeCompletionAllocator &getAllocator() const { return Allocator; }

    CodeCompletionTUInfo &getCodeCompletionTUInfo() const { return CCTUInfo; }

    /// \brief Determine whether the given declaration is at all interesting
    /// as a code-completion result.
    ///
    /// \param ND the declaration that we are inspecting.
    ///
    /// \param AsNestedNameSpecifier will be set true if this declaration is
    /// only interesting when it is a nested-name-specifier.
    bool isInterestingDecl(const NamedDecl *ND,
                           bool &AsNestedNameSpecifier) const;

    /// \brief Check whether the result is hidden by the Hiding declaration.
    ///
    /// \returns true if the result is hidden and cannot be found, false if
    /// the hidden result could still be found. When false, \p R may be
    /// modified to describe how the result can be found (e.g., via extra
    /// qualification).
    bool CheckHiddenResult(Result &R, DeclContext *CurContext,
                           const NamedDecl *Hiding);

    /// \brief Add a new result to this result set (if it isn't already in one
    /// of the shadow maps), or replace an existing result (for, e.g., a
    /// redeclaration).
    ///
    /// \param R the result to add (if it is unique).
    ///
    /// \param CurContext the context in which this result will be named.
    void MaybeAddResult(Result R, DeclContext *CurContext = 0);

    /// \brief Add a new result to this result set, where we already know
    /// the hiding declation (if any).
    ///
    /// \param R the result to add (if it is unique).
    ///
    /// \param CurContext the context in which this result will be named.
    ///
    /// \param Hiding the declaration that hides the result.
    ///
    /// \param InBaseClass whether the result was found in a base
    /// class of the searched context.
    void AddResult(Result R, DeclContext *CurContext, NamedDecl *Hiding,
                   bool InBaseClass);

    /// \brief Add a new non-declaration result to this result set.
    void AddResult(Result R);

    /// \brief Enter into a new scope.
    void EnterNewScope();

    /// \brief Exit from the current scope.
    void ExitScope();

    /// \brief Ignore this declaration, if it is seen again.
    void Ignore(const Decl *D) { AllDeclsFound.insert(D->getCanonicalDecl()); }

    /// \name Name lookup predicates
    ///
    /// These predicates can be passed to the name lookup functions to filter the
    /// results of name lookup. All of the predicates have the same type, so that
    ///
    //@{
    bool IsOrdinaryName(const NamedDecl *ND) const;
    bool IsOrdinaryNonTypeName(const NamedDecl *ND) const;
    bool IsIntegralConstantValue(const NamedDecl *ND) const;
    bool IsOrdinaryNonValueName(const NamedDecl *ND) const;
    bool IsNestedNameSpecifier(const NamedDecl *ND) const;
    bool IsEnum(const NamedDecl *ND) const;
    bool IsClassOrStruct(const NamedDecl *ND) const;
    bool IsUnion(const NamedDecl *ND) const;
    bool IsNamespace(const NamedDecl *ND) const;
    bool IsNamespaceOrAlias(const NamedDecl *ND) const;
    bool IsType(const NamedDecl *ND) const;
    bool IsMember(const NamedDecl *ND) const;
    bool IsObjCIvar(const NamedDecl *ND) const;
    bool IsObjCMessageReceiver(const NamedDecl *ND) const;
    bool IsObjCMessageReceiverOrLambdaCapture(const NamedDecl *ND) const;
    bool IsObjCCollection(const NamedDecl *ND) const;
    bool IsImpossibleToSatisfy(const NamedDecl *ND) const;
    //@}
  };
}

class ResultBuilder::ShadowMapEntry::iterator {
  llvm::PointerUnion<const NamedDecl *, const DeclIndexPair *> DeclOrIterator;
  unsigned SingleDeclIndex;

public:
  typedef DeclIndexPair value_type;
  typedef value_type reference;
  typedef std::ptrdiff_t difference_type;
  typedef std::input_iterator_tag iterator_category;

  class pointer {
    DeclIndexPair Value;

  public:
    pointer(const DeclIndexPair &Value) : Value(Value) { }

    const DeclIndexPair *operator->() const {
      return &Value;
    }
  };

  iterator() : DeclOrIterator((NamedDecl *)0), SingleDeclIndex(0) { }

  iterator(const NamedDecl *SingleDecl, unsigned Index)
    : DeclOrIterator(SingleDecl), SingleDeclIndex(Index) { }

  iterator(const DeclIndexPair *Iterator)
    : DeclOrIterator(Iterator), SingleDeclIndex(0) { }

  iterator &operator++() {
    if (DeclOrIterator.is<const NamedDecl *>()) {
      DeclOrIterator = (NamedDecl *)0;
      SingleDeclIndex = 0;
      return *this;
    }

    const DeclIndexPair *I = DeclOrIterator.get<const DeclIndexPair*>();
    ++I;
    DeclOrIterator = I;
    return *this;
  }

  /*iterator operator++(int) {
    iterator tmp(*this);
    ++(*this);
    return tmp;
  }*/

  reference operator*() const {
    if (const NamedDecl *ND = DeclOrIterator.dyn_cast<const NamedDecl *>())
      return reference(ND, SingleDeclIndex);

    return *DeclOrIterator.get<const DeclIndexPair*>();
  }

  pointer operator->() const {
    return pointer(**this);
  }

  friend bool operator==(const iterator &X, const iterator &Y) {
    return X.DeclOrIterator.getOpaqueValue()
                                  == Y.DeclOrIterator.getOpaqueValue() &&
      X.SingleDeclIndex == Y.SingleDeclIndex;
  }

  friend bool operator!=(const iterator &X, const iterator &Y) {
    return !(X == Y);
  }
};

ResultBuilder::ShadowMapEntry::iterator
ResultBuilder::ShadowMapEntry::begin() const {
  if (DeclOrVector.isNull())
    return iterator();

  if (const NamedDecl *ND = DeclOrVector.dyn_cast<const NamedDecl *>())
    return iterator(ND, SingleDeclIndex);

  return iterator(DeclOrVector.get<DeclIndexPairVector *>()->begin());
}

ResultBuilder::ShadowMapEntry::iterator
ResultBuilder::ShadowMapEntry::end() const {
  if (DeclOrVector.is<const NamedDecl *>() || DeclOrVector.isNull())
    return iterator();

  return iterator(DeclOrVector.get<DeclIndexPairVector *>()->end());
}

/// \brief Compute the qualification required to get from the current context
/// (\p CurContext) to the target context (\p TargetContext).
///
/// \param Context the AST context in which the qualification will be used.
///
/// \param CurContext the context where an entity is being named, which is
/// typically based on the current scope.
///
/// \param TargetContext the context in which the named entity actually
/// resides.
///
/// \returns a nested name specifier that refers into the target context, or
/// NULL if no qualification is needed.
static NestedNameSpecifier *
getRequiredQualification(ASTContext &Context,
                         const DeclContext *CurContext,
                         const DeclContext *TargetContext) {
  SmallVector<const DeclContext *, 4> TargetParents;

  for (const DeclContext *CommonAncestor = TargetContext;
       CommonAncestor && !CommonAncestor->Encloses(CurContext);
       CommonAncestor = CommonAncestor->getLookupParent()) {
    if (CommonAncestor->isTransparentContext() ||
        CommonAncestor->isFunctionOrMethod())
      continue;

    TargetParents.push_back(CommonAncestor);
  }

  NestedNameSpecifier *Result = 0;
  while (!TargetParents.empty()) {
    const DeclContext *Parent = TargetParents.back();
    TargetParents.pop_back();

    if (const NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(Parent)) {
      if (!Namespace->getIdentifier())
        continue;

      Result = NestedNameSpecifier::Create(Context, Result, Namespace);
    }
    else if (const TagDecl *TD = dyn_cast<TagDecl>(Parent))
      Result = NestedNameSpecifier::Create(Context, Result,
                                           false,
                                     Context.getTypeDeclType(TD).getTypePtr());
  }
  return Result;
}

bool ResultBuilder::isInterestingDecl(const NamedDecl *ND,
                                      bool &AsNestedNameSpecifier) const {
  AsNestedNameSpecifier = false;

  ND = ND->getUnderlyingDecl();
  unsigned IDNS = ND->getIdentifierNamespace();

  // Skip unnamed entities.
  if (!ND->getDeclName())
    return false;

  // Friend declarations and declarations introduced due to friends are never
  // added as results.
  if (IDNS & (Decl::IDNS_OrdinaryFriend | Decl::IDNS_TagFriend))
    return false;

  // Class template (partial) specializations are never added as results.
  if (isa<ClassTemplateSpecializationDecl>(ND) ||
      isa<ClassTemplatePartialSpecializationDecl>(ND))
    return false;

  // Using declarations themselves are never added as results.
  if (isa<UsingDecl>(ND))
    return false;

  // Some declarations have reserved names that we don't want to ever show.
  if (const IdentifierInfo *Id = ND->getIdentifier()) {
    // __va_list_tag is a freak of nature. Find it and skip it.
    if (Id->isStr("__va_list_tag") || Id->isStr("__builtin_va_list"))
      return false;

    // Filter out names reserved for the implementation (C99 7.1.3,
    // C++ [lib.global.names]) if they come from a system header.
    //
    // FIXME: Add predicate for this.
    if (Id->getLength() >= 2) {
      const char *Name = Id->getNameStart();
      if (Name[0] == '_' &&
          (Name[1] == '_' || (Name[1] >= 'A' && Name[1] <= 'Z')) &&
          (ND->getLocation().isInvalid() ||
           SemaRef.SourceMgr.isInSystemHeader(
                          SemaRef.SourceMgr.getSpellingLoc(ND->getLocation()))))
        return false;
    }
  }

  if (Filter == &ResultBuilder::IsNestedNameSpecifier ||
      ((isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND)) &&
       Filter != &ResultBuilder::IsNamespace &&
       Filter != &ResultBuilder::IsNamespaceOrAlias &&
       Filter != 0))
    AsNestedNameSpecifier = true;

  // Filter out any unwanted results.
  if (Filter && !(this->*Filter)(ND)) {
    // Check whether it is interesting as a nested-name-specifier.
    if (AllowNestedNameSpecifiers && SemaRef.getLangOpts().CPlusPlus &&
        IsNestedNameSpecifier(ND) &&
        (Filter != &ResultBuilder::IsMember ||
         (isa<CXXRecordDecl>(ND) &&
          cast<CXXRecordDecl>(ND)->isInjectedClassName()))) {
      AsNestedNameSpecifier = true;
      return true;
    }

    return false;
  }
  // ... then it must be interesting!
  return true;
}

bool ResultBuilder::CheckHiddenResult(Result &R, DeclContext *CurContext,
                                      const NamedDecl *Hiding) {
  // In C, there is no way to refer to a hidden name.
  // FIXME: This isn't true; we can find a tag name hidden by an ordinary
  // name if we introduce the tag type.
  if (!SemaRef.getLangOpts().CPlusPlus)
    return true;

  const DeclContext *HiddenCtx =
      R.Declaration->getDeclContext()->getRedeclContext();

  // There is no way to qualify a name declared in a function or method.
  if (HiddenCtx->isFunctionOrMethod())
    return true;

  if (HiddenCtx == Hiding->getDeclContext()->getRedeclContext())
    return true;

  // We can refer to the result with the appropriate qualification. Do it.
  R.Hidden = true;
  R.QualifierIsInformative = false;

  if (!R.Qualifier)
    R.Qualifier = getRequiredQualification(SemaRef.Context,
                                           CurContext,
                                           R.Declaration->getDeclContext());
  return false;
}

/// \brief A simplified classification of types used to determine whether two
/// types are "similar enough" when adjusting priorities.
SimplifiedTypeClass clang::getSimplifiedTypeClass(CanQualType T) {
  switch (T->getTypeClass()) {
  case Type::Builtin:
    switch (cast<BuiltinType>(T)->getKind()) {
      case BuiltinType::Void:
        return STC_Void;

      case BuiltinType::NullPtr:
        return STC_Pointer;

      case BuiltinType::Overload:
      case BuiltinType::Dependent:
        return STC_Other;

      case BuiltinType::ObjCId:
      case BuiltinType::ObjCClass:
      case BuiltinType::ObjCSel:
        return STC_ObjectiveC;

      default:
        return STC_Arithmetic;
    }

  case Type::Complex:
    return STC_Arithmetic;

  case Type::Pointer:
    return STC_Pointer;

  case Type::BlockPointer:
    return STC_Block;

  case Type::LValueReference:
  case Type::RValueReference:
    return getSimplifiedTypeClass(T->getAs<ReferenceType>()->getPointeeType());

  case Type::ConstantArray:
  case Type::IncompleteArray:
  case Type::VariableArray:
  case Type::DependentSizedArray:
    return STC_Array;

  case Type::DependentSizedExtVector:
  case Type::Vector:
  case Type::ExtVector:
    return STC_Arithmetic;

  case Type::FunctionProto:
  case Type::FunctionNoProto:
    return STC_Function;

  case Type::Record:
    return STC_Record;

  case Type::Enum:
    return STC_Arithmetic;

  case Type::ObjCObject:
  case Type::ObjCInterface:
  case Type::ObjCObjectPointer:
    return STC_ObjectiveC;

  default:
    return STC_Other;
  }
}

/// \brief Get the type that a given expression will have if this declaration
/// is used as an expression in its "typical" code-completion form.
QualType clang::getDeclUsageType(ASTContext &C, const NamedDecl *ND) {
  ND = cast<NamedDecl>(ND->getUnderlyingDecl());

  if (const TypeDecl *Type = dyn_cast<TypeDecl>(ND))
    return C.getTypeDeclType(Type);
  if (const ObjCInterfaceDecl *Iface = dyn_cast<ObjCInterfaceDecl>(ND))
    return C.getObjCInterfaceType(Iface);

  QualType T;
  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(ND))
    T = Function->getCallResultType();
  else if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(ND))
    T = Method->getSendResultType();
  else if (const FunctionTemplateDecl *FunTmpl =
               dyn_cast<FunctionTemplateDecl>(ND))
    T = FunTmpl->getTemplatedDecl()->getCallResultType();
  else if (const EnumConstantDecl *Enumerator = dyn_cast<EnumConstantDecl>(ND))
    T = C.getTypeDeclType(cast<EnumDecl>(Enumerator->getDeclContext()));
  else if (const ObjCPropertyDecl *Property = dyn_cast<ObjCPropertyDecl>(ND))
    T = Property->getType();
  else if (const ValueDecl *Value = dyn_cast<ValueDecl>(ND))
    T = Value->getType();
  else
    return QualType();

  // Dig through references, function pointers, and block pointers to
  // get down to the likely type of an expression when the entity is
  // used.
  do {
    if (const ReferenceType *Ref = T->getAs<ReferenceType>()) {
      T = Ref->getPointeeType();
      continue;
    }

    if (const PointerType *Pointer = T->getAs<PointerType>()) {
      if (Pointer->getPointeeType()->isFunctionType()) {
        T = Pointer->getPointeeType();
        continue;
      }

      break;
    }

    if (const BlockPointerType *Block = T->getAs<BlockPointerType>()) {
      T = Block->getPointeeType();
      continue;
    }

    if (const FunctionType *Function = T->getAs<FunctionType>()) {
      T = Function->getResultType();
      continue;
    }

    break;
  } while (true);

  return T;
}

unsigned ResultBuilder::getBasePriority(const NamedDecl *ND) {
  if (!ND)
    return CCP_Unlikely;

  // Context-based decisions.
  const DeclContext *DC = ND->getDeclContext()->getRedeclContext();
  if (DC->isFunctionOrMethod() || isa<BlockDecl>(DC)) {
    // _cmd is relatively rare
    if (const ImplicitParamDecl *ImplicitParam =
        dyn_cast<ImplicitParamDecl>(ND))
      if (ImplicitParam->getIdentifier() &&
          ImplicitParam->getIdentifier()->isStr("_cmd"))
        return CCP_ObjC_cmd;

    return CCP_LocalDeclaration;
  }
  if (DC->isRecord() || isa<ObjCContainerDecl>(DC))
    return CCP_MemberDeclaration;

  // Content-based decisions.
  if (isa<EnumConstantDecl>(ND))
    return CCP_Constant;

  // Use CCP_Type for type declarations unless we're in a statement, Objective-C
  // message receiver, or parenthesized expression context. There, it's as
  // likely that the user will want to write a type as other declarations.
  if ((isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND)) &&
      !(CompletionContext.getKind() == CodeCompletionContext::CCC_Statement ||
        CompletionContext.getKind()
          == CodeCompletionContext::CCC_ObjCMessageReceiver ||
        CompletionContext.getKind()
          == CodeCompletionContext::CCC_ParenthesizedExpression))
    return CCP_Type;

  return CCP_Declaration;
}

void ResultBuilder::AdjustResultPriorityForDecl(Result &R) {
  // If this is an Objective-C method declaration whose selector matches our
  // preferred selector, give it a priority boost.
  if (!PreferredSelector.isNull())
    if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(R.Declaration))
      if (PreferredSelector == Method->getSelector())
        R.Priority += CCD_SelectorMatch;

  // If we have a preferred type, adjust the priority for results with exactly-
  // matching or nearly-matching types.
  if (!PreferredType.isNull()) {
    QualType T = getDeclUsageType(SemaRef.Context, R.Declaration);
    if (!T.isNull()) {
      CanQualType TC = SemaRef.Context.getCanonicalType(T);
      // Check for exactly-matching types (modulo qualifiers).
      if (SemaRef.Context.hasSameUnqualifiedType(PreferredType, TC))
        R.Priority /= CCF_ExactTypeMatch;
      // Check for nearly-matching types, based on classification of each.
      else if ((getSimplifiedTypeClass(PreferredType)
                                               == getSimplifiedTypeClass(TC)) &&
               !(PreferredType->isEnumeralType() && TC->isEnumeralType()))
        R.Priority /= CCF_SimilarTypeMatch;
    }
  }
}

void ResultBuilder::MaybeAddConstructorResults(Result R) {
  if (!SemaRef.getLangOpts().CPlusPlus || !R.Declaration ||
      !CompletionContext.wantConstructorResults())
    return;

  ASTContext &Context = SemaRef.Context;
  const NamedDecl *D = R.Declaration;
  const CXXRecordDecl *Record = 0;
  if (const ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(D))
    Record = ClassTemplate->getTemplatedDecl();
  else if ((Record = dyn_cast<CXXRecordDecl>(D))) {
    // Skip specializations and partial specializations.
    if (isa<ClassTemplateSpecializationDecl>(Record))
      return;
  } else {
    // There are no constructors here.
    return;
  }

  Record = Record->getDefinition();
  if (!Record)
    return;


  QualType RecordTy = Context.getTypeDeclType(Record);
  DeclarationName ConstructorName
    = Context.DeclarationNames.getCXXConstructorName(
                                           Context.getCanonicalType(RecordTy));
  DeclContext::lookup_const_result Ctors = Record->lookup(ConstructorName);
  for (DeclContext::lookup_const_iterator I = Ctors.begin(),
                                          E = Ctors.end();
       I != E; ++I) {
    R.Declaration = *I;
    R.CursorKind = getCursorKindForDecl(R.Declaration);
    Results.push_back(R);
  }
}

void ResultBuilder::MaybeAddResult(Result R, DeclContext *CurContext) {
  assert(!ShadowMaps.empty() && "Must enter into a results scope");

  if (R.Kind != Result::RK_Declaration) {
    // For non-declaration results, just add the result.
    Results.push_back(R);
    return;
  }

  // Look through using declarations.
  if (const UsingShadowDecl *Using =
          dyn_cast<UsingShadowDecl>(R.Declaration)) {
    MaybeAddResult(Result(Using->getTargetDecl(),
                          getBasePriority(Using->getTargetDecl()),
                          R.Qualifier),
                   CurContext);
    return;
  }

  const Decl *CanonDecl = R.Declaration->getCanonicalDecl();
  unsigned IDNS = CanonDecl->getIdentifierNamespace();

  bool AsNestedNameSpecifier = false;
  if (!isInterestingDecl(R.Declaration, AsNestedNameSpecifier))
    return;

  // C++ constructors are never found by name lookup.
  if (isa<CXXConstructorDecl>(R.Declaration))
    return;

  ShadowMap &SMap = ShadowMaps.back();
  ShadowMapEntry::iterator I, IEnd;
  ShadowMap::iterator NamePos = SMap.find(R.Declaration->getDeclName());
  if (NamePos != SMap.end()) {
    I = NamePos->second.begin();
    IEnd = NamePos->second.end();
  }

  for (; I != IEnd; ++I) {
    const NamedDecl *ND = I->first;
    unsigned Index = I->second;
    if (ND->getCanonicalDecl() == CanonDecl) {
      // This is a redeclaration. Always pick the newer declaration.
      Results[Index].Declaration = R.Declaration;

      // We're done.
      return;
    }
  }

  // This is a new declaration in this scope. However, check whether this
  // declaration name is hidden by a similarly-named declaration in an outer
  // scope.
  std::list<ShadowMap>::iterator SM, SMEnd = ShadowMaps.end();
  --SMEnd;
  for (SM = ShadowMaps.begin(); SM != SMEnd; ++SM) {
    ShadowMapEntry::iterator I, IEnd;
    ShadowMap::iterator NamePos = SM->find(R.Declaration->getDeclName());
    if (NamePos != SM->end()) {
      I = NamePos->second.begin();
      IEnd = NamePos->second.end();
    }
    for (; I != IEnd; ++I) {
      // A tag declaration does not hide a non-tag declaration.
      if (I->first->hasTagIdentifierNamespace() &&
          (IDNS & (Decl::IDNS_Member | Decl::IDNS_Ordinary |
                   Decl::IDNS_ObjCProtocol)))
        continue;

      // Protocols are in distinct namespaces from everything else.
      if (((I->first->getIdentifierNamespace() & Decl::IDNS_ObjCProtocol)
           || (IDNS & Decl::IDNS_ObjCProtocol)) &&
          I->first->getIdentifierNamespace() != IDNS)
        continue;

      // The newly-added result is hidden by an entry in the shadow map.
      if (CheckHiddenResult(R, CurContext, I->first))
        return;

      break;
    }
  }

  // Make sure that any given declaration only shows up in the result set once.
  if (!AllDeclsFound.insert(CanonDecl))
    return;

  // If the filter is for nested-name-specifiers, then this result starts a
  // nested-name-specifier.
  if (AsNestedNameSpecifier) {
    R.StartsNestedNameSpecifier = true;
    R.Priority = CCP_NestedNameSpecifier;
  } else
      AdjustResultPriorityForDecl(R);

  // If this result is supposed to have an informative qualifier, add one.
  if (R.QualifierIsInformative && !R.Qualifier &&
      !R.StartsNestedNameSpecifier) {
    const DeclContext *Ctx = R.Declaration->getDeclContext();
    if (const NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(Ctx))
      R.Qualifier = NestedNameSpecifier::Create(SemaRef.Context, 0, Namespace);
    else if (const TagDecl *Tag = dyn_cast<TagDecl>(Ctx))
      R.Qualifier = NestedNameSpecifier::Create(SemaRef.Context, 0, false,
                             SemaRef.Context.getTypeDeclType(Tag).getTypePtr());
    else
      R.QualifierIsInformative = false;
  }

  // Insert this result into the set of results and into the current shadow
  // map.
  SMap[R.Declaration->getDeclName()].Add(R.Declaration, Results.size());
  Results.push_back(R);

  if (!AsNestedNameSpecifier)
    MaybeAddConstructorResults(R);
}

void ResultBuilder::AddResult(Result R, DeclContext *CurContext,
                              NamedDecl *Hiding, bool InBaseClass = false) {
  if (R.Kind != Result::RK_Declaration) {
    // For non-declaration results, just add the result.
    Results.push_back(R);
    return;
  }

  // Look through using declarations.
  if (const UsingShadowDecl *Using = dyn_cast<UsingShadowDecl>(R.Declaration)) {
    AddResult(Result(Using->getTargetDecl(),
                     getBasePriority(Using->getTargetDecl()),
                     R.Qualifier),
              CurContext, Hiding);
    return;
  }

  bool AsNestedNameSpecifier = false;
  if (!isInterestingDecl(R.Declaration, AsNestedNameSpecifier))
    return;

  // C++ constructors are never found by name lookup.
  if (isa<CXXConstructorDecl>(R.Declaration))
    return;

  if (Hiding && CheckHiddenResult(R, CurContext, Hiding))
    return;

  // Make sure that any given declaration only shows up in the result set once.
  if (!AllDeclsFound.insert(R.Declaration->getCanonicalDecl()))
    return;

  // If the filter is for nested-name-specifiers, then this result starts a
  // nested-name-specifier.
  if (AsNestedNameSpecifier) {
    R.StartsNestedNameSpecifier = true;
    R.Priority = CCP_NestedNameSpecifier;
  }
  else if (Filter == &ResultBuilder::IsMember && !R.Qualifier && InBaseClass &&
           isa<CXXRecordDecl>(R.Declaration->getDeclContext()
                                                  ->getRedeclContext()))
    R.QualifierIsInformative = true;

  // If this result is supposed to have an informative qualifier, add one.
  if (R.QualifierIsInformative && !R.Qualifier &&
      !R.StartsNestedNameSpecifier) {
    const DeclContext *Ctx = R.Declaration->getDeclContext();
    if (const NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(Ctx))
      R.Qualifier = NestedNameSpecifier::Create(SemaRef.Context, 0, Namespace);
    else if (const TagDecl *Tag = dyn_cast<TagDecl>(Ctx))
      R.Qualifier = NestedNameSpecifier::Create(SemaRef.Context, 0, false,
                            SemaRef.Context.getTypeDeclType(Tag).getTypePtr());
    else
      R.QualifierIsInformative = false;
  }

  // Adjust the priority if this result comes from a base class.
  if (InBaseClass)
    R.Priority += CCD_InBaseClass;

  AdjustResultPriorityForDecl(R);

  if (HasObjectTypeQualifiers)
    if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(R.Declaration))
      if (Method->isInstance()) {
        Qualifiers MethodQuals
                        = Qualifiers::fromCVRMask(Method->getTypeQualifiers());
        if (ObjectTypeQualifiers == MethodQuals)
          R.Priority += CCD_ObjectQualifierMatch;
        else if (ObjectTypeQualifiers - MethodQuals) {
          // The method cannot be invoked, because doing so would drop
          // qualifiers.
          return;
        }
      }

  // Insert this result into the set of results.
  Results.push_back(R);

  if (!AsNestedNameSpecifier)
    MaybeAddConstructorResults(R);
}

void ResultBuilder::AddResult(Result R) {
  assert(R.Kind != Result::RK_Declaration &&
          "Declaration results need more context");
  Results.push_back(R);
}

/// \brief Enter into a new scope.
void ResultBuilder::EnterNewScope() {
  ShadowMaps.push_back(ShadowMap());
}

/// \brief Exit from the current scope.
void ResultBuilder::ExitScope() {
  for (ShadowMap::iterator E = ShadowMaps.back().begin(),
                        EEnd = ShadowMaps.back().end();
       E != EEnd;
       ++E)
    E->second.Destroy();

  ShadowMaps.pop_back();
}

/// \brief Determines whether this given declaration will be found by
/// ordinary name lookup.
bool ResultBuilder::IsOrdinaryName(const NamedDecl *ND) const {
  ND = cast<NamedDecl>(ND->getUnderlyingDecl());

  unsigned IDNS = Decl::IDNS_Ordinary;
  if (SemaRef.getLangOpts().CPlusPlus)
    IDNS |= Decl::IDNS_Tag | Decl::IDNS_Namespace | Decl::IDNS_Member;
  else if (SemaRef.getLangOpts().ObjC1) {
    if (isa<ObjCIvarDecl>(ND))
      return true;
  }

  return ND->getIdentifierNamespace() & IDNS;
}

/// \brief Determines whether this given declaration will be found by
/// ordinary name lookup but is not a type name.
bool ResultBuilder::IsOrdinaryNonTypeName(const NamedDecl *ND) const {
  ND = cast<NamedDecl>(ND->getUnderlyingDecl());
  if (isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND))
    return false;

  unsigned IDNS = Decl::IDNS_Ordinary;
  if (SemaRef.getLangOpts().CPlusPlus)
    IDNS |= Decl::IDNS_Tag | Decl::IDNS_Namespace | Decl::IDNS_Member;
  else if (SemaRef.getLangOpts().ObjC1) {
    if (isa<ObjCIvarDecl>(ND))
      return true;
  }

  return ND->getIdentifierNamespace() & IDNS;
}

bool ResultBuilder::IsIntegralConstantValue(const NamedDecl *ND) const {
  if (!IsOrdinaryNonTypeName(ND))
    return 0;

  if (const ValueDecl *VD = dyn_cast<ValueDecl>(ND->getUnderlyingDecl()))
    if (VD->getType()->isIntegralOrEnumerationType())
      return true;

  return false;
}

/// \brief Determines whether this given declaration will be found by
/// ordinary name lookup.
bool ResultBuilder::IsOrdinaryNonValueName(const NamedDecl *ND) const {
  ND = cast<NamedDecl>(ND->getUnderlyingDecl());

  unsigned IDNS = Decl::IDNS_Ordinary;
  if (SemaRef.getLangOpts().CPlusPlus)
    IDNS |= Decl::IDNS_Tag | Decl::IDNS_Namespace;

  return (ND->getIdentifierNamespace() & IDNS) &&
    !isa<ValueDecl>(ND) && !isa<FunctionTemplateDecl>(ND) &&
    !isa<ObjCPropertyDecl>(ND);
}

/// \brief Determines whether the given declaration is suitable as the
/// start of a C++ nested-name-specifier, e.g., a class or namespace.
bool ResultBuilder::IsNestedNameSpecifier(const NamedDecl *ND) const {
  // Allow us to find class templates, too.
  if (const ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(ND))
    ND = ClassTemplate->getTemplatedDecl();

  return SemaRef.isAcceptableNestedNameSpecifier(ND);
}

/// \brief Determines whether the given declaration is an enumeration.
bool ResultBuilder::IsEnum(const NamedDecl *ND) const {
  return isa<EnumDecl>(ND);
}

/// \brief Determines whether the given declaration is a class or struct.
bool ResultBuilder::IsClassOrStruct(const NamedDecl *ND) const {
  // Allow us to find class templates, too.
  if (const ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(ND))
    ND = ClassTemplate->getTemplatedDecl();

  // For purposes of this check, interfaces match too.
  if (const RecordDecl *RD = dyn_cast<RecordDecl>(ND))
    return RD->getTagKind() == TTK_Class ||
    RD->getTagKind() == TTK_Struct ||
    RD->getTagKind() == TTK_Interface;

  return false;
}

/// \brief Determines whether the given declaration is a union.
bool ResultBuilder::IsUnion(const NamedDecl *ND) const {
  // Allow us to find class templates, too.
  if (const ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(ND))
    ND = ClassTemplate->getTemplatedDecl();

  if (const RecordDecl *RD = dyn_cast<RecordDecl>(ND))
    return RD->getTagKind() == TTK_Union;

  return false;
}

/// \brief Determines whether the given declaration is a namespace.
bool ResultBuilder::IsNamespace(const NamedDecl *ND) const {
  return isa<NamespaceDecl>(ND);
}

/// \brief Determines whether the given declaration is a namespace or
/// namespace alias.
bool ResultBuilder::IsNamespaceOrAlias(const NamedDecl *ND) const {
  return isa<NamespaceDecl>(ND) || isa<NamespaceAliasDecl>(ND);
}

/// \brief Determines whether the given declaration is a type.
bool ResultBuilder::IsType(const NamedDecl *ND) const {
  if (const UsingShadowDecl *Using = dyn_cast<UsingShadowDecl>(ND))
    ND = Using->getTargetDecl();

  return isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND);
}

/// \brief Determines which members of a class should be visible via
/// "." or "->".  Only value declarations, nested name specifiers, and
/// using declarations thereof should show up.
bool ResultBuilder::IsMember(const NamedDecl *ND) const {
  if (const UsingShadowDecl *Using = dyn_cast<UsingShadowDecl>(ND))
    ND = Using->getTargetDecl();

  return isa<ValueDecl>(ND) || isa<FunctionTemplateDecl>(ND) ||
    isa<ObjCPropertyDecl>(ND);
}

static bool isObjCReceiverType(ASTContext &C, QualType T) {
  T = C.getCanonicalType(T);
  switch (T->getTypeClass()) {
  case Type::ObjCObject:
  case Type::ObjCInterface:
  case Type::ObjCObjectPointer:
    return true;

  case Type::Builtin:
    switch (cast<BuiltinType>(T)->getKind()) {
    case BuiltinType::ObjCId:
    case BuiltinType::ObjCClass:
    case BuiltinType::ObjCSel:
      return true;

    default:
      break;
    }
    return false;

  default:
    break;
  }

  if (!C.getLangOpts().CPlusPlus)
    return false;

  // FIXME: We could perform more analysis here to determine whether a
  // particular class type has any conversions to Objective-C types. For now,
  // just accept all class types.
  return T->isDependentType() || T->isRecordType();
}

bool ResultBuilder::IsObjCMessageReceiver(const NamedDecl *ND) const {
  QualType T = getDeclUsageType(SemaRef.Context, ND);
  if (T.isNull())
    return false;

  T = SemaRef.Context.getBaseElementType(T);
  return isObjCReceiverType(SemaRef.Context, T);
}

bool ResultBuilder::IsObjCMessageReceiverOrLambdaCapture(const NamedDecl *ND) const {
  if (IsObjCMessageReceiver(ND))
    return true;

  const VarDecl *Var = dyn_cast<VarDecl>(ND);
  if (!Var)
    return false;

  return Var->hasLocalStorage() && !Var->hasAttr<BlocksAttr>();
}

bool ResultBuilder::IsObjCCollection(const NamedDecl *ND) const {
  if ((SemaRef.getLangOpts().CPlusPlus && !IsOrdinaryName(ND)) ||
      (!SemaRef.getLangOpts().CPlusPlus && !IsOrdinaryNonTypeName(ND)))
    return false;

  QualType T = getDeclUsageType(SemaRef.Context, ND);
  if (T.isNull())
    return false;

  T = SemaRef.Context.getBaseElementType(T);
  return T->isObjCObjectType() || T->isObjCObjectPointerType() ||
         T->isObjCIdType() ||
         (SemaRef.getLangOpts().CPlusPlus && T->isRecordType());
}

bool ResultBuilder::IsImpossibleToSatisfy(const NamedDecl *ND) const {
  return false;
}

/// \brief Determines whether the given declaration is an Objective-C
/// instance variable.
bool ResultBuilder::IsObjCIvar(const NamedDecl *ND) const {
  return isa<ObjCIvarDecl>(ND);
}

namespace {
  /// \brief Visible declaration consumer that adds a code-completion result
  /// for each visible declaration.
  class CodeCompletionDeclConsumer : public VisibleDeclConsumer {
    ResultBuilder &Results;
    DeclContext *CurContext;

  public:
    CodeCompletionDeclConsumer(ResultBuilder &Results, DeclContext *CurContext)
      : Results(Results), CurContext(CurContext) { }

    virtual void FoundDecl(NamedDecl *ND, NamedDecl *Hiding, DeclContext *Ctx,
                           bool InBaseClass) {
      bool Accessible = true;
      if (Ctx)
        Accessible = Results.getSema().IsSimplyAccessible(ND, Ctx);

      ResultBuilder::Result Result(ND, Results.getBasePriority(ND), 0, false,
                                   Accessible);
      Results.AddResult(Result, CurContext, Hiding, InBaseClass);
    }
  };
}

/// \brief Add type specifiers for the current language as keyword results.
static void AddTypeSpecifierResults(const LangOptions &LangOpts,
                                    ResultBuilder &Results) {
  typedef CodeCompletionResult Result;
  Results.AddResult(Result("short", CCP_Type));
  Results.AddResult(Result("long", CCP_Type));
  Results.AddResult(Result("signed", CCP_Type));
  Results.AddResult(Result("unsigned", CCP_Type));
  Results.AddResult(Result("void", CCP_Type));
  Results.AddResult(Result("char", CCP_Type));
  Results.AddResult(Result("int", CCP_Type));
  Results.AddResult(Result("float", CCP_Type));
  Results.AddResult(Result("double", CCP_Type));
  Results.AddResult(Result("enum", CCP_Type));
  Results.AddResult(Result("struct", CCP_Type));
  Results.AddResult(Result("union", CCP_Type));
  Results.AddResult(Result("const", CCP_Type));
  Results.AddResult(Result("volatile", CCP_Type));

  if (LangOpts.C99) {
    // C99-specific
    Results.AddResult(Result("_Complex", CCP_Type));
    Results.AddResult(Result("_Imaginary", CCP_Type));
    Results.AddResult(Result("_Bool", CCP_Type));
    Results.AddResult(Result("restrict", CCP_Type));
  }

  CodeCompletionBuilder Builder(Results.getAllocator(),
                                Results.getCodeCompletionTUInfo());
  if (LangOpts.CPlusPlus) {
    // C++-specific
    Results.AddResult(Result("bool", CCP_Type +
                             (LangOpts.ObjC1? CCD_bool_in_ObjC : 0)));
    Results.AddResult(Result("class", CCP_Type));
    Results.AddResult(Result("wchar_t", CCP_Type));

    // typename qualified-id
    Builder.AddTypedTextChunk("typename");
    Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
    Builder.AddPlaceholderChunk("qualifier");
    Builder.AddTextChunk("::");
    Builder.AddPlaceholderChunk("name");
    Results.AddResult(Result(Builder.TakeString()));

    if (LangOpts.CPlusPlus11) {
      Results.AddResult(Result("auto", CCP_Type));
      Results.AddResult(Result("char16_t", CCP_Type));
      Results.AddResult(Result("char32_t", CCP_Type));

      Builder.AddTypedTextChunk("decltype");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));
    }
  }

  // GNU extensions
  if (LangOpts.GNUMode) {
    // FIXME: Enable when we actually support decimal floating point.
    //    Results.AddResult(Result("_Decimal32"));
    //    Results.AddResult(Result("_Decimal64"));
    //    Results.AddResult(Result("_Decimal128"));

    Builder.AddTypedTextChunk("typeof");
    Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
    Builder.AddPlaceholderChunk("expression");
    Results.AddResult(Result(Builder.TakeString()));

    Builder.AddTypedTextChunk("typeof");
    Builder.AddChunk(CodeCompletionString::CK_LeftParen);
    Builder.AddPlaceholderChunk("type");
    Builder.AddChunk(CodeCompletionString::CK_RightParen);
    Results.AddResult(Result(Builder.TakeString()));
  }
}

static void AddStorageSpecifiers(Sema::ParserCompletionContext CCC,
                                 const LangOptions &LangOpts,
                                 ResultBuilder &Results) {
  typedef CodeCompletionResult Result;
  // Note: we don't suggest either "auto" or "register", because both
  // are pointless as storage specifiers. Elsewhere, we suggest "auto"
  // in C++0x as a type specifier.
  Results.AddResult(Result("extern"));
  Results.AddResult(Result("static"));
}

static void AddFunctionSpecifiers(Sema::ParserCompletionContext CCC,
                                  const LangOptions &LangOpts,
                                  ResultBuilder &Results) {
  typedef CodeCompletionResult Result;
  switch (CCC) {
  case Sema::PCC_Class:
  case Sema::PCC_MemberTemplate:
    if (LangOpts.CPlusPlus) {
      Results.AddResult(Result("explicit"));
      Results.AddResult(Result("friend"));
      Results.AddResult(Result("mutable"));
      Results.AddResult(Result("virtual"));
    }
    // Fall through

  case Sema::PCC_ObjCInterface:
  case Sema::PCC_ObjCImplementation:
  case Sema::PCC_Namespace:
  case Sema::PCC_Template:
    if (LangOpts.CPlusPlus || LangOpts.C99)
      Results.AddResult(Result("inline"));
    break;

  case Sema::PCC_ObjCInstanceVariableList:
  case Sema::PCC_Expression:
  case Sema::PCC_Statement:
  case Sema::PCC_ForInit:
  case Sema::PCC_Condition:
  case Sema::PCC_RecoveryInFunction:
  case Sema::PCC_Type:
  case Sema::PCC_ParenthesizedExpression:
  case Sema::PCC_LocalDeclarationSpecifiers:
    break;
  }
}

static void AddObjCExpressionResults(ResultBuilder &Results, bool NeedAt);
static void AddObjCStatementResults(ResultBuilder &Results, bool NeedAt);
static void AddObjCVisibilityResults(const LangOptions &LangOpts,
                                     ResultBuilder &Results,
                                     bool NeedAt);
static void AddObjCImplementationResults(const LangOptions &LangOpts,
                                         ResultBuilder &Results,
                                         bool NeedAt);
static void AddObjCInterfaceResults(const LangOptions &LangOpts,
                                    ResultBuilder &Results,
                                    bool NeedAt);
static void AddObjCTopLevelResults(ResultBuilder &Results, bool NeedAt);

static void AddTypedefResult(ResultBuilder &Results) {
  CodeCompletionBuilder Builder(Results.getAllocator(),
                                Results.getCodeCompletionTUInfo());
  Builder.AddTypedTextChunk("typedef");
  Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
  Builder.AddPlaceholderChunk("type");
  Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
  Builder.AddPlaceholderChunk("name");
  Results.AddResult(CodeCompletionResult(Builder.TakeString()));
}

static bool WantTypesInContext(Sema::ParserCompletionContext CCC,
                               const LangOptions &LangOpts) {
  switch (CCC) {
  case Sema::PCC_Namespace:
  case Sema::PCC_Class:
  case Sema::PCC_ObjCInstanceVariableList:
  case Sema::PCC_Template:
  case Sema::PCC_MemberTemplate:
  case Sema::PCC_Statement:
  case Sema::PCC_RecoveryInFunction:
  case Sema::PCC_Type:
  case Sema::PCC_ParenthesizedExpression:
  case Sema::PCC_LocalDeclarationSpecifiers:
    return true;

  case Sema::PCC_Expression:
  case Sema::PCC_Condition:
    return LangOpts.CPlusPlus;

  case Sema::PCC_ObjCInterface:
  case Sema::PCC_ObjCImplementation:
    return false;

  case Sema::PCC_ForInit:
    return LangOpts.CPlusPlus || LangOpts.ObjC1 || LangOpts.C99;
  }

  llvm_unreachable("Invalid ParserCompletionContext!");
}

static PrintingPolicy getCompletionPrintingPolicy(const ASTContext &Context,
                                                  const Preprocessor &PP) {
  PrintingPolicy Policy = Sema::getPrintingPolicy(Context, PP);
  Policy.AnonymousTagLocations = false;
  Policy.SuppressStrongLifetime = true;
  Policy.SuppressUnwrittenScope = true;
  return Policy;
}

/// \brief Retrieve a printing policy suitable for code completion.
static PrintingPolicy getCompletionPrintingPolicy(Sema &S) {
  return getCompletionPrintingPolicy(S.Context, S.PP);
}

/// \brief Retrieve the string representation of the given type as a string
/// that has the appropriate lifetime for code completion.
///
/// This routine provides a fast path where we provide constant strings for
/// common type names.
static const char *GetCompletionTypeString(QualType T,
                                           ASTContext &Context,
                                           const PrintingPolicy &Policy,
                                           CodeCompletionAllocator &Allocator) {
  if (!T.getLocalQualifiers()) {
    // Built-in type names are constant strings.
    if (const BuiltinType *BT = dyn_cast<BuiltinType>(T))
      return BT->getNameAsCString(Policy);

    // Anonymous tag types are constant strings.
    if (const TagType *TagT = dyn_cast<TagType>(T))
      if (TagDecl *Tag = TagT->getDecl())
        if (!Tag->hasNameForLinkage()) {
          switch (Tag->getTagKind()) {
          case TTK_Struct: return "struct <anonymous>";
          case TTK_Interface: return "__interface <anonymous>";
          case TTK_Class:  return "class <anonymous>";
          case TTK_Union:  return "union <anonymous>";
          case TTK_Enum:   return "enum <anonymous>";
          }
        }
  }

  // Slow path: format the type as a string.
  std::string Result;
  T.getAsStringInternal(Result, Policy);
  return Allocator.CopyString(Result);
}

/// \brief Add a completion for "this", if we're in a member function.
static void addThisCompletion(Sema &S, ResultBuilder &Results) {
  QualType ThisTy = S.getCurrentThisType();
  if (ThisTy.isNull())
    return;

  CodeCompletionAllocator &Allocator = Results.getAllocator();
  CodeCompletionBuilder Builder(Allocator, Results.getCodeCompletionTUInfo());
  PrintingPolicy Policy = getCompletionPrintingPolicy(S);
  Builder.AddResultTypeChunk(GetCompletionTypeString(ThisTy,
                                                     S.Context,
                                                     Policy,
                                                     Allocator));
  Builder.AddTypedTextChunk("this");
  Results.AddResult(CodeCompletionResult(Builder.TakeString()));
}

/// \brief Add language constructs that show up for "ordinary" names.
static void AddOrdinaryNameResults(Sema::ParserCompletionContext CCC,
                                   Scope *S,
                                   Sema &SemaRef,
                                   ResultBuilder &Results) {
  CodeCompletionAllocator &Allocator = Results.getAllocator();
  CodeCompletionBuilder Builder(Allocator, Results.getCodeCompletionTUInfo());
  PrintingPolicy Policy = getCompletionPrintingPolicy(SemaRef);

  typedef CodeCompletionResult Result;
  switch (CCC) {
  case Sema::PCC_Namespace:
    if (SemaRef.getLangOpts().CPlusPlus) {
      if (Results.includeCodePatterns()) {
        // namespace <identifier> { declarations }
        Builder.AddTypedTextChunk("namespace");
        Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
        Builder.AddPlaceholderChunk("identifier");
        Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
        Builder.AddPlaceholderChunk("declarations");
        Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
        Builder.AddChunk(CodeCompletionString::CK_RightBrace);
        Results.AddResult(Result(Builder.TakeString()));
      }

      // namespace identifier = identifier ;
      Builder.AddTypedTextChunk("namespace");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("name");
      Builder.AddChunk(CodeCompletionString::CK_Equal);
      Builder.AddPlaceholderChunk("namespace");
      Results.AddResult(Result(Builder.TakeString()));

      // Using directives
      Builder.AddTypedTextChunk("using");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddTextChunk("namespace");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("identifier");
      Results.AddResult(Result(Builder.TakeString()));

      // asm(string-literal)
      Builder.AddTypedTextChunk("asm");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("string-literal");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));

      if (Results.includeCodePatterns()) {
        // Explicit template instantiation
        Builder.AddTypedTextChunk("template");
        Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
        Builder.AddPlaceholderChunk("declaration");
        Results.AddResult(Result(Builder.TakeString()));
      }
    }

    if (SemaRef.getLangOpts().ObjC1)
      AddObjCTopLevelResults(Results, true);

    AddTypedefResult(Results);
    // Fall through

  case Sema::PCC_Class:
    if (SemaRef.getLangOpts().CPlusPlus) {
      // Using declaration
      Builder.AddTypedTextChunk("using");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("qualifier");
      Builder.AddTextChunk("::");
      Builder.AddPlaceholderChunk("name");
      Results.AddResult(Result(Builder.TakeString()));

      // using typename qualifier::name (only in a dependent context)
      if (SemaRef.CurContext->isDependentContext()) {
        Builder.AddTypedTextChunk("using");
        Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
        Builder.AddTextChunk("typename");
        Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
        Builder.AddPlaceholderChunk("qualifier");
        Builder.AddTextChunk("::");
        Builder.AddPlaceholderChunk("name");
        Results.AddResult(Result(Builder.TakeString()));
      }

      if (CCC == Sema::PCC_Class) {
        AddTypedefResult(Results);

        // public:
        Builder.AddTypedTextChunk("public");
        if (Results.includeCodePatterns())
          Builder.AddChunk(CodeCompletionString::CK_Colon);
        Results.AddResult(Result(Builder.TakeString()));

        // protected:
        Builder.AddTypedTextChunk("protected");
        if (Results.includeCodePatterns())
          Builder.AddChunk(CodeCompletionString::CK_Colon);
        Results.AddResult(Result(Builder.TakeString()));

        // private:
        Builder.AddTypedTextChunk("private");
        if (Results.includeCodePatterns())
          Builder.AddChunk(CodeCompletionString::CK_Colon);
        Results.AddResult(Result(Builder.TakeString()));
      }
    }
    // Fall through

  case Sema::PCC_Template:
  case Sema::PCC_MemberTemplate:
    if (SemaRef.getLangOpts().CPlusPlus && Results.includeCodePatterns()) {
      // template < parameters >
      Builder.AddTypedTextChunk("template");
      Builder.AddChunk(CodeCompletionString::CK_LeftAngle);
      Builder.AddPlaceholderChunk("parameters");
      Builder.AddChunk(CodeCompletionString::CK_RightAngle);
      Results.AddResult(Result(Builder.TakeString()));
    }

    AddStorageSpecifiers(CCC, SemaRef.getLangOpts(), Results);
    AddFunctionSpecifiers(CCC, SemaRef.getLangOpts(), Results);
    break;

  case Sema::PCC_ObjCInterface:
    AddObjCInterfaceResults(SemaRef.getLangOpts(), Results, true);
    AddStorageSpecifiers(CCC, SemaRef.getLangOpts(), Results);
    AddFunctionSpecifiers(CCC, SemaRef.getLangOpts(), Results);
    break;

  case Sema::PCC_ObjCImplementation:
    AddObjCImplementationResults(SemaRef.getLangOpts(), Results, true);
    AddStorageSpecifiers(CCC, SemaRef.getLangOpts(), Results);
    AddFunctionSpecifiers(CCC, SemaRef.getLangOpts(), Results);
    break;

  case Sema::PCC_ObjCInstanceVariableList:
    AddObjCVisibilityResults(SemaRef.getLangOpts(), Results, true);
    break;

  case Sema::PCC_RecoveryInFunction:
  case Sema::PCC_Statement: {
    AddTypedefResult(Results);

    if (SemaRef.getLangOpts().CPlusPlus && Results.includeCodePatterns() &&
        SemaRef.getLangOpts().CXXExceptions) {
      Builder.AddTypedTextChunk("try");
      Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
      Builder.AddPlaceholderChunk("statements");
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddChunk(CodeCompletionString::CK_RightBrace);
      Builder.AddTextChunk("catch");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("declaration");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
      Builder.AddPlaceholderChunk("statements");
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddChunk(CodeCompletionString::CK_RightBrace);
      Results.AddResult(Result(Builder.TakeString()));
    }
    if (SemaRef.getLangOpts().ObjC1)
      AddObjCStatementResults(Results, true);

    if (Results.includeCodePatterns()) {
      // if (condition) { statements }
      Builder.AddTypedTextChunk("if");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      if (SemaRef.getLangOpts().CPlusPlus)
        Builder.AddPlaceholderChunk("condition");
      else
        Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
      Builder.AddPlaceholderChunk("statements");
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddChunk(CodeCompletionString::CK_RightBrace);
      Results.AddResult(Result(Builder.TakeString()));

      // switch (condition) { }
      Builder.AddTypedTextChunk("switch");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      if (SemaRef.getLangOpts().CPlusPlus)
        Builder.AddPlaceholderChunk("condition");
      else
        Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddChunk(CodeCompletionString::CK_RightBrace);
      Results.AddResult(Result(Builder.TakeString()));
    }

    // Switch-specific statements.
    if (!SemaRef.getCurFunction()->SwitchStack.empty()) {
      // case expression:
      Builder.AddTypedTextChunk("case");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_Colon);
      Results.AddResult(Result(Builder.TakeString()));

      // default:
      Builder.AddTypedTextChunk("default");
      Builder.AddChunk(CodeCompletionString::CK_Colon);
      Results.AddResult(Result(Builder.TakeString()));
    }

    if (Results.includeCodePatterns()) {
      /// while (condition) { statements }
      Builder.AddTypedTextChunk("while");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      if (SemaRef.getLangOpts().CPlusPlus)
        Builder.AddPlaceholderChunk("condition");
      else
        Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
      Builder.AddPlaceholderChunk("statements");
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddChunk(CodeCompletionString::CK_RightBrace);
      Results.AddResult(Result(Builder.TakeString()));

      // do { statements } while ( expression );
      Builder.AddTypedTextChunk("do");
      Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
      Builder.AddPlaceholderChunk("statements");
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddChunk(CodeCompletionString::CK_RightBrace);
      Builder.AddTextChunk("while");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));

      // for ( for-init-statement ; condition ; expression ) { statements }
      Builder.AddTypedTextChunk("for");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      if (SemaRef.getLangOpts().CPlusPlus || SemaRef.getLangOpts().C99)
        Builder.AddPlaceholderChunk("init-statement");
      else
        Builder.AddPlaceholderChunk("init-expression");
      Builder.AddChunk(CodeCompletionString::CK_SemiColon);
      Builder.AddPlaceholderChunk("condition");
      Builder.AddChunk(CodeCompletionString::CK_SemiColon);
      Builder.AddPlaceholderChunk("inc-expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddChunk(CodeCompletionString::CK_LeftBrace);
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddPlaceholderChunk("statements");
      Builder.AddChunk(CodeCompletionString::CK_VerticalSpace);
      Builder.AddChunk(CodeCompletionString::CK_RightBrace);
      Results.AddResult(Result(Builder.TakeString()));
    }

    if (S->getContinueParent()) {
      // continue ;
      Builder.AddTypedTextChunk("continue");
      Results.AddResult(Result(Builder.TakeString()));
    }

    if (S->getBreakParent()) {
      // break ;
      Builder.AddTypedTextChunk("break");
      Results.AddResult(Result(Builder.TakeString()));
    }

    // "return expression ;" or "return ;", depending on whether we
    // know the function is void or not.
    bool isVoid = false;
    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(SemaRef.CurContext))
      isVoid = Function->getResultType()->isVoidType();
    else if (ObjCMethodDecl *Method
                                 = dyn_cast<ObjCMethodDecl>(SemaRef.CurContext))
      isVoid = Method->getResultType()->isVoidType();
    else if (SemaRef.getCurBlock() &&
             !SemaRef.getCurBlock()->ReturnType.isNull())
      isVoid = SemaRef.getCurBlock()->ReturnType->isVoidType();
    Builder.AddTypedTextChunk("return");
    if (!isVoid) {
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("expression");
    }
    Results.AddResult(Result(Builder.TakeString()));

    // goto identifier ;
    Builder.AddTypedTextChunk("goto");
    Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
    Builder.AddPlaceholderChunk("label");
    Results.AddResult(Result(Builder.TakeString()));

    // Using directives
    Builder.AddTypedTextChunk("using");
    Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
    Builder.AddTextChunk("namespace");
    Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
    Builder.AddPlaceholderChunk("identifier");
    Results.AddResult(Result(Builder.TakeString()));
  }

  // Fall through (for statement expressions).
  case Sema::PCC_ForInit:
  case Sema::PCC_Condition:
    AddStorageSpecifiers(CCC, SemaRef.getLangOpts(), Results);
    // Fall through: conditions and statements can have expressions.

  case Sema::PCC_ParenthesizedExpression:
    if (SemaRef.getLangOpts().ObjCAutoRefCount &&
        CCC == Sema::PCC_ParenthesizedExpression) {
      // (__bridge <type>)<expression>
      Builder.AddTypedTextChunk("__bridge");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("type");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddPlaceholderChunk("expression");
      Results.AddResult(Result(Builder.TakeString()));

      // (__bridge_transfer <Objective-C type>)<expression>
      Builder.AddTypedTextChunk("__bridge_transfer");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("Objective-C type");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddPlaceholderChunk("expression");
      Results.AddResult(Result(Builder.TakeString()));

      // (__bridge_retained <CF type>)<expression>
      Builder.AddTypedTextChunk("__bridge_retained");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("CF type");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Builder.AddPlaceholderChunk("expression");
      Results.AddResult(Result(Builder.TakeString()));
    }
    // Fall through

  case Sema::PCC_Expression: {
    if (SemaRef.getLangOpts().CPlusPlus) {
      // 'this', if we're in a non-static member function.
      addThisCompletion(SemaRef, Results);

      // true
      Builder.AddResultTypeChunk("bool");
      Builder.AddTypedTextChunk("true");
      Results.AddResult(Result(Builder.TakeString()));

      // false
      Builder.AddResultTypeChunk("bool");
      Builder.AddTypedTextChunk("false");
      Results.AddResult(Result(Builder.TakeString()));

      if (SemaRef.getLangOpts().RTTI) {
        // dynamic_cast < type-id > ( expression )
        Builder.AddTypedTextChunk("dynamic_cast");
        Builder.AddChunk(CodeCompletionString::CK_LeftAngle);
        Builder.AddPlaceholderChunk("type");
        Builder.AddChunk(CodeCompletionString::CK_RightAngle);
        Builder.AddChunk(CodeCompletionString::CK_LeftParen);
        Builder.AddPlaceholderChunk("expression");
        Builder.AddChunk(CodeCompletionString::CK_RightParen);
        Results.AddResult(Result(Builder.TakeString()));
      }

      // static_cast < type-id > ( expression )
      Builder.AddTypedTextChunk("static_cast");
      Builder.AddChunk(CodeCompletionString::CK_LeftAngle);
      Builder.AddPlaceholderChunk("type");
      Builder.AddChunk(CodeCompletionString::CK_RightAngle);
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));

      // reinterpret_cast < type-id > ( expression )
      Builder.AddTypedTextChunk("reinterpret_cast");
      Builder.AddChunk(CodeCompletionString::CK_LeftAngle);
      Builder.AddPlaceholderChunk("type");
      Builder.AddChunk(CodeCompletionString::CK_RightAngle);
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));

      // const_cast < type-id > ( expression )
      Builder.AddTypedTextChunk("const_cast");
      Builder.AddChunk(CodeCompletionString::CK_LeftAngle);
      Builder.AddPlaceholderChunk("type");
      Builder.AddChunk(CodeCompletionString::CK_RightAngle);
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("expression");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));

      if (SemaRef.getLangOpts().RTTI) {
        // typeid ( expression-or-type )
        Builder.AddResultTypeChunk("std::type_info");
        Builder.AddTypedTextChunk("typeid");
        Builder.AddChunk(CodeCompletionString::CK_LeftParen);
        Builder.AddPlaceholderChunk("expression-or-type");
        Builder.AddChunk(CodeCompletionString::CK_RightParen);
        Results.AddResult(Result(Builder.TakeString()));
      }

      // new T ( ... )
      Builder.AddTypedTextChunk("new");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("type");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("expressions");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));

      // new T [ ] ( ... )
      Builder.AddTypedTextChunk("new");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("type");
      Builder.AddChunk(CodeCompletionString::CK_LeftBracket);
      Builder.AddPlaceholderChunk("size");
      Builder.AddChunk(CodeCompletionString::CK_RightBracket);
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("expressions");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));

      // delete expression
      Builder.AddResultTypeChunk("void");
      Builder.AddTypedTextChunk("delete");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("expression");
      Results.AddResult(Result(Builder.TakeString()));

      // delete [] expression
      Builder.AddResultTypeChunk("void");
      Builder.AddTypedTextChunk("delete");
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddChunk(CodeCompletionString::CK_LeftBracket);
      Builder.AddChunk(CodeCompletionString::CK_RightBracket);
      Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
      Builder.AddPlaceholderChunk("expression");
      Results.AddResult(Result(Builder.TakeString()));

      if (SemaRef.getLangOpts().CXXExceptions) {
        // throw expression
        Builder.AddResultTypeChunk("void");
        Builder.AddTypedTextChunk("throw");
        Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
        Builder.AddPlaceholderChunk("expression");
        Results.AddResult(Result(Builder.TakeString()));
      }

      // FIXME: Rethrow?

      if (SemaRef.getLangOpts().CPlusPlus11) {
        // nullptr
        Builder.AddResultTypeChunk("std::nullptr_t");
        Builder.AddTypedTextChunk("nullptr");
        Results.AddResult(Result(Builder.TakeString()));

        // alignof
        Builder.AddResultTypeChunk("size_t");
        Builder.AddTypedTextChunk("alignof");
        Builder.AddChunk(CodeCompletionString::CK_LeftParen);
        Builder.AddPlaceholderChunk("type");
        Builder.AddChunk(CodeCompletionString::CK_RightParen);
        Results.AddResult(Result(Builder.TakeString()));

        // noexcept
        Builder.AddResultTypeChunk("bool");
        Builder.AddTypedTextChunk("noexcept");
        Builder.AddChunk(CodeCompletionString::CK_LeftParen);
        Builder.AddPlaceholderChunk("expression");
        Builder.AddChunk(CodeCompletionString::CK_RightParen);
        Results.AddResult(Result(Builder.TakeString()));

        // sizeof... expression
        Builder.AddResultTypeChunk("size_t");
        Builder.AddTypedTextChunk("sizeof...");
        Builder.AddChunk(CodeCompletionString::CK_LeftParen);
        Builder.AddPlaceholderChunk("parameter-pack");
        Builder.AddChunk(CodeCompletionString::CK_RightParen);
        Results.AddResult(Result(Builder.TakeString()));
      }
    }

    if (SemaRef.getLangOpts().ObjC1) {
      // Add "super", if we're in an Objective-C class with a superclass.
      if (ObjCMethodDecl *Method = SemaRef.getCurMethodDecl()) {
        // The interface can be NULL.
        if (ObjCInterfaceDecl *ID = Method->getClassInterface())
          if (ID->getSuperClass()) {
            std::string SuperType;
            SuperType = ID->getSuperClass()->getNameAsString();
            if (Method->isInstanceMethod())
              SuperType += " *";

            Builder.AddResultTypeChunk(Allocator.CopyString(SuperType));
            Builder.AddTypedTextChunk("super");
            Results.AddResult(Result(Builder.TakeString()));
          }
      }

      AddObjCExpressionResults(Results, true);
    }

    if (SemaRef.getLangOpts().C11) {
      // _Alignof
      Builder.AddResultTypeChunk("size_t");
      if (SemaRef.getASTContext().Idents.get("alignof").hasMacroDefinition())
        Builder.AddTypedTextChunk("alignof");
      else
        Builder.AddTypedTextChunk("_Alignof");
      Builder.AddChunk(CodeCompletionString::CK_LeftParen);
      Builder.AddPlaceholderChunk("type");
      Builder.AddChunk(CodeCompletionString::CK_RightParen);
      Results.AddResult(Result(Builder.TakeString()));
    }

    // sizeof expression
    Builder.AddResultTypeChunk("size_t");
    Builder.AddTypedTextChunk("sizeof");
    Builder.AddChunk(CodeCompletionString::CK_LeftParen);
    Builder.AddPlaceholderChunk("expression-or-type");
    Builder.AddChunk(CodeCompletionString::CK_RightParen);
    Results.AddResult(Result(Builder.TakeString()));
    break;
  }

  case Sema::PCC_Type:
  case Sema::PCC_LocalDeclarationSpecifiers:
    break;
  }

  if (WantTypesInContext(CCC, SemaRef.getLangOpts()))
    AddTypeSpecifierResults(SemaRef.getLangOpts(), Results);

  if (SemaRef.getLangOpts().CPlusPlus && CCC != Sema::PCC_Type)
    Results.AddResult(Result("operator"));
}

/// \brief If the given declaration has an associated type, add it as a result
/// type chunk.
static void AddResultTypeChunk(ASTContext &Context,
                               const PrintingPolicy &Policy,
                               const NamedDecl *ND,
                               CodeCompletionBuilder &Result) {
  if (!ND)
    return;

  // Skip constructors and conversion functions, which have their return types
  // built into their names.
  if (isa<CXXConstructorDecl>(ND) || isa<CXXConversionDecl>(ND))
    return;

  // Determine the type of the declaration (if it has a type).
  QualType T;
  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(ND))
    T = Function->getResultType();
  else if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(ND))
    T = Method->getResultType();
  else if (const FunctionTemplateDecl *FunTmpl =
               dyn_cast<FunctionTemplateDecl>(ND))
    T = FunTmpl->getTemplatedDecl()->getResultType();
  else if (const EnumConstantDecl *Enumerator = dyn_cast<EnumConstantDecl>(ND))
    T = Context.getTypeDeclType(cast<TypeDecl>(Enumerator->getDeclContext()));
  else if (isa<UnresolvedUsingValueDecl>(ND)) {
    /* Do nothing: ignore unresolved using declarations*/
  } else if (const ValueDecl *Value = dyn_cast<ValueDecl>(ND)) {
    T = Value->getType();
  } else if (const ObjCPropertyDecl *Property = dyn_cast<ObjCPropertyDecl>(ND))
    T = Property->getType();

  if (T.isNull() || Context.hasSameType(T, Context.DependentTy))
    return;

  Result.AddResultTypeChunk(GetCompletionTypeString(T, Context, Policy,
                                                    Result.getAllocator()));
}

static void MaybeAddSentinel(ASTContext &Context,
                             const NamedDecl *FunctionOrMethod,
                             CodeCompletionBuilder &Result) {
  if (SentinelAttr *Sentinel = FunctionOrMethod->getAttr<SentinelAttr>())
    if (Sentinel->getSentinel() == 0) {
      if (Context.getLangOpts().ObjC1 &&
          Context.Idents.get("nil").hasMacroDefinition())
        Result.AddTextChunk(", nil");
      else if (Context.Idents.get("NULL").hasMacroDefinition())
        Result.AddTextChunk(", NULL");
      else
        Result.AddTextChunk(", (void*)0");
    }
}

static std::string formatObjCParamQualifiers(unsigned ObjCQuals) {
  std::string Result;
  if (ObjCQuals & Decl::OBJC_TQ_In)
    Result += "in ";
  else if (ObjCQuals & Decl::OBJC_TQ_Inout)
    Result += "inout ";
  else if (ObjCQuals & Decl::OBJC_TQ_Out)
    Result += "out ";
  if (ObjCQuals & Decl::OBJC_TQ_Bycopy)
    Result += "bycopy ";
  else if (ObjCQuals & Decl::OBJC_TQ_Byref)
    Result += "byref ";
  if (ObjCQuals & Decl::OBJC_TQ_Oneway)
    Result += "oneway ";
  return Result;
}

static std::string FormatFunctionParameter(ASTContext &Context,
                                           const PrintingPolicy &Policy,
                                           const ParmVarDecl *Param,
                                           bool SuppressName = false,
                                           bool SuppressBlock = false) {
  bool ObjCMethodParam = isa<ObjCMethodDecl>(Param->getDeclContext());
  if (Param->getType()->isDependentType() ||
      !Param->getType()->isBlockPointerType()) {
    // The argument for a dependent or non-block parameter is a placeholder
    // containing that parameter's type.
    std::string Result;

    if (Param->getIdentifier() && !ObjCMethodParam && !SuppressName)
      Result = Param->getIdentifier()->getName();

    Param->getType().getAsStringInternal(Result, Policy);

    if (ObjCMethodParam) {
      Result = "(" + formatObjCParamQualifiers(Param->getObjCDeclQualifier())
             + Result + ")";
      if (Param->getIdentifier() && !SuppressName)
        Result += Param->getIdentifier()->getName();
    }
    return Result;
  }

  // The argument for a block pointer parameter is a block literal with
  // the appropriate type.
  FunctionTypeLoc Block;
  FunctionProtoTypeLoc BlockProto;
  TypeLoc TL;
  if (TypeSourceInfo *TSInfo = Param->getTypeSourceInfo()) {
    TL = TSInfo->getTypeLoc().getUnqualifiedLoc();
    while (true) {
      // Look through typedefs.
      if (!SuppressBlock) {
        if (TypedefTypeLoc TypedefTL = TL.getAs<TypedefTypeLoc>()) {
          if (TypeSourceInfo *InnerTSInfo =
                  TypedefTL.getTypedefNameDecl()->getTypeSourceInfo()) {
            TL = InnerTSInfo->getTypeLoc().getUnqualifiedLoc();
            continue;
          }
        }

        // Look through qualified types
        if (QualifiedTypeLoc QualifiedTL = TL.getAs<QualifiedTypeLoc>()) {
          TL = QualifiedTL.getUnqualifiedLoc();
          continue;
        }
      }

      // Try to get the function prototype behind the block pointer type,
      // then we're done.
      if (BlockPointerTypeLoc BlockPtr = TL.getAs<BlockPointerTypeLoc>()) {
        TL = BlockPtr.getPointeeLoc().IgnoreParens();
        Block = TL.getAs<FunctionTypeLoc>();
        BlockProto = TL.getAs<FunctionProtoTypeLoc>();
      }
      break;
    }
  }

  if (!Block) {
    // We were unable to find a FunctionProtoTypeLoc with parameter names
    // for the block; just use the parameter type as a placeholder.
    std::string Result;
    if (!ObjCMethodParam && Param->getIdentifier())
      Result = Param->getIdentifier()->getName();

    Param->getType().getUnqualifiedType().getAsStringInternal(Result, Policy);

    if (ObjCMethodParam) {
      Result = "(" + formatObjCParamQualifiers(Param->getObjCDeclQualifier())
             + Result + ")";
      if (Param->getIdentifier())
        Result += Param->getIdentifier()->getName();
    }

    return Result;
  }

  // We have the function prototype behind the block pointer type, as it was
  // written in the source.
  std::string Result;
  QualType ResultType = Block.getTypePtr()->getResultType();
  if (!ResultType->isVoidType() || SuppressBlock)
    ResultType.getAsStringInternal(Result, Policy);

  // Format the parameter list.
  std::string Params;
  if (!BlockProto || Block.getNumArgs() == 0) {
    if (BlockProto && BlockProto.getTypePtr()->isVariadic())
      Params = "(...)";
    else
      Params = "(void)";
  } else {
    Params += "(";
    for (unsigned I = 0, N = Block.getNumArgs(); I != N; ++I) {
      if (I)
        Params += ", ";
      Params += FormatFunctionParameter(Context, Policy, Block.getArg(I),
                                        /*SuppressName=*/false,
                                        /*SuppressBlock=*/true);

      if (I == N - 1 && BlockProto.getTypePtr()->isVariadic())
        Params += ", ...";
    }
    Params += ")";
  }

  if (SuppressBlock) {
    // Format as a parameter.
    Result = Result + " (^";
    if (Param->getIdentifier())
      Result += Param->getIdentifier()->getName();
    Result += ")";
    Result += Params;
  } else {
    // Format as a block literal argument.
    Result = '^' + Result;
    Result += Params;

    if (Param->getIdentifier())
      Result += Param->getIdentifier()->getName();
  }

  return Result;
}

/// \brief Add function parameter chunks to the given code completion string.
static void AddFunctionParameterChunks(ASTContext &Context,
                                       const PrintingPolicy &Policy,
                                       const FunctionDecl *Function,
                                       CodeCompletionBuilder &Result,
                                       unsigned Start = 0,
                                       bool InOptional = false) {
  bool FirstParameter = true;

  for (unsigned P = Start, N = Function->getNumParams(); P != N; ++P) {
    const ParmVarDecl *Param = Function->getParamDecl(P);

    if (Param->hasDefaultArg() && !InOptional) {
      // When we see an optional default argument, put that argument and
      // the remaining default arguments into a new, optional string.
      CodeCompletionBuilder Opt(Result.getAllocator(),
                                Result.getCodeCompletionTUInfo());
      if (!FirstParameter)
        Opt.AddChunk(CodeCompletionString::CK_Comma);
      AddFunctionParameterChunks(Context, Policy, Function, Opt, P, true);
      Result.AddOptionalChunk(Opt.TakeString());
      break;
    }

    if (FirstParameter)
      FirstParameter = false;
    else
      Result.AddChunk(CodeCompletionString::CK_Comma);

    InOptional = false;

    // Format the placeholder string.
    std::string PlaceholderStr = FormatFunctionParameter(Context, Policy,
                                                         Param);

    if (Function->isVariadic() && P == N - 1)
      PlaceholderStr += ", ...";

    // Add the placeholder string.
    Result.AddPlaceholderChunk(
                             Result.getAllocator().CopyString(PlaceholderStr));
  }

  if (const FunctionProtoType *Proto
        = Function->getType()->getAs<FunctionProtoType>())
    if (Proto->isVariadic()) {
      if (Proto->getNumArgs() == 0)
        Result.AddPlaceholderChunk("...");

      MaybeAddSentinel(Context, Function, Result);
    }
}

/// \brief Add template parameter chunks to the given code completion string.
static void AddTemplateParameterChunks(ASTContext &Context,
                                       const PrintingPolicy &Policy,
                                       const TemplateDecl *Template,
                                       CodeCompletionBuilder &Result,
                                       unsigned MaxParameters = 0,
                                       unsigned Start = 0,
                                       bool InDefaultArg = false) {
  bool FirstParameter = true;

  TemplateParameterList *Params = Template->getTemplateParameters();
  TemplateParameterList::iterator PEnd = Params->end();
  if (MaxParameters)
    PEnd = Params->begin() + MaxParameters;
  for (TemplateParameterList::iterator P = Params->begin() + Start;
       P != PEnd; ++P) {
    bool HasDefaultArg = false;
    std::string PlaceholderStr;
    if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*P)) {
      if (TTP->wasDeclaredWithTypename())
        PlaceholderStr = "typename";
      else
        PlaceholderStr = "class";

      if (TTP->getIdentifier()) {
        PlaceholderStr += ' ';
        PlaceholderStr += TTP->getIdentifier()->getName();
      }

      HasDefaultArg = TTP->hasDefaultArgument();
    } else if (NonTypeTemplateParmDecl *NTTP
                                    = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
      if (NTTP->getIdentifier())
        PlaceholderStr = NTTP->getIdentifier()->getName();
      NTTP->getType().getAsStringInternal(PlaceholderStr, Policy);
      HasDefaultArg = NTTP->hasDefaultArgument();
    } else {
      assert(isa<TemplateTemplateParmDecl>(*P));
      TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);

      // Since putting the template argument list into the placeholder would
      // be very, very long, we just use an abbreviation.
      PlaceholderStr = "template<...> class";
      if (TTP->getIdentifier()) {
        PlaceholderStr += ' ';
        PlaceholderStr += TTP->getIdentifier()->getName();
      }

      HasDefaultArg = TTP->hasDefaultArgument();
    }

    if (HasDefaultArg && !InDefaultArg) {
      // When we see an optional default argument, put that argument and
      // the remaining default arguments into a new, optional string.
      CodeCompletionBuilder Opt(Result.getAllocator(),
                                Result.getCodeCompletionTUInfo());
      if (!FirstParameter)
        Opt.AddChunk(CodeCompletionString::CK_Comma);
      AddTemplateParameterChunks(Context, Policy, Template, Opt, MaxParameters,
                                 P - Params->begin(), true);
      Result.AddOptionalChunk(Opt.TakeString());
      break;
    }

    InDefaultArg = false;

    if (FirstParameter)
      FirstParameter = false;
    else
      Result.AddChunk(CodeCompletionString::CK_Comma);

    // Add the placeholder string.
    Result.AddPlaceholderChunk(
                              Result.getAllocator().CopyString(PlaceholderStr));
  }
}

/// \brief Add a qualifier to the given code-completion string, if the
/// provided nested-name-specifier is non-NULL.
static void
AddQualifierToCompletionString(CodeCompletionBuilder &Result,
                               NestedNameSpecifier *Qualifier,
                               bool QualifierIsInformative,
                               ASTContext &Context,
                               const PrintingPolicy &Policy) {
  if (!Qualifier)
    return;

  std::string PrintedNNS;
  {
    llvm::raw_string_ostream OS(PrintedNNS);
    Qualifier->print(OS, Policy);
  }
  if (QualifierIsInformative)
    Result.AddInformativeChunk(Result.getAllocator().CopyString(PrintedNNS));
  else
    Result.AddTextChunk(Result.getAllocator().CopyString(PrintedNNS));
}

static void
AddFunctionTypeQualsToCompletionString(CodeCompletionBuilder &Result,
                                       const FunctionDecl *Function) {
  const FunctionProtoType *Proto
    = Function->getType()->getAs<FunctionProtoType>();
  if (!Proto || !Proto->getTypeQuals())
    return;

  // FIXME: Add ref-qualifier!

  // Handle single qualifiers without copying
  if (Proto->getTypeQuals() == Qualifiers::Const) {
    Result.AddInformativeChunk(" const");
    return;
  }

  if (Proto->getTypeQuals() == Qualifiers::Volatile) {
    Result.AddInformativeChunk(" volatile");
    return;
  }

  if (Proto->getTypeQuals() == Qualifiers::Restrict) {
    Result.AddInformativeChunk(" restrict");
    return;
  }

  // Handle multiple qualifiers.
  std::string QualsStr;
  if (Proto->isConst())
    QualsStr += " const";
  if (Proto->isVolatile())
    QualsStr += " volatile";
  if (Proto->isRestrict())
    QualsStr += " restrict";
  Result.AddInformativeChunk(Result.getAllocator().CopyString(QualsStr));
}

/// \brief Add the name of the given declaration
static void AddTypedNameChunk(ASTContext &Context, const PrintingPolicy &Policy,
                              const NamedDecl *ND,
                              CodeCompletionBuilder &Result) {
  DeclarationName Name = ND->getDeclName();
  if (!Name)
    return;

  switch (Name.getNameKind()) {
    case DeclarationName::CXXOperatorName: {
      const char *OperatorName = 0;
      switch (Name.getCXXOverloadedOperator()) {
      case OO_None:
      case OO_Conditional:
      case NUM_OVERLOADED_OPERATORS:
        OperatorName = "operator";
        break;

#define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
      case OO_##Name: OperatorName = "operator" Spelling; break;
#define OVERLOADED_OPERATOR_MULTI(Name,Spelling,Unary,Binary,MemberOnly)
#include "clang/Basic/OperatorKinds.def"

      case OO_New:          OperatorName = "operator new"; break;
      case OO_Delete:       OperatorName = "operator delete"; break;
      case OO_Array_New:    OperatorName = "operator new[]"; break;
      case OO_Array_Delete: OperatorName = "operator delete[]"; break;
      case OO_Call:         OperatorName = "operator()"; break;
      case OO_Subscript:    OperatorName = "operator[]"; break;
      }
      Result.AddTypedTextChunk(OperatorName);
      break;
    }

  case DeclarationName::Identifier:
  case DeclarationName::CXXConversionFunctionName:
  case DeclarationName::CXXDestructorName:
  case DeclarationName::CXXLiteralOperatorName:
    Result.AddTypedTextChunk(
                      Result.getAllocator().CopyString(ND->getNameAsString()));
    break;

  case DeclarationName::CXXUsingDirective:
  case DeclarationName::ObjCZeroArgSelector:
  case DeclarationName::ObjCOneArgSelector:
  case DeclarationName::ObjCMultiArgSelector:
    break;

  case DeclarationName::CXXConstructorName: {
    CXXRecordDecl *Record = 0;
    QualType Ty = Name.getCXXNameType();
    if (const RecordType *RecordTy = Ty->getAs<RecordType>())
      Record = cast<CXXRecordDecl>(RecordTy->getDecl());
    else if (const InjectedClassNameType *InjectedTy
                                        = Ty->getAs<InjectedClassNameType>())
      Record = InjectedTy->getDecl();
    else {
      Result.AddTypedTextChunk(
                      Result.getAllocator().CopyString(ND->getNameAsString()));
      break;
    }

    Result.AddTypedTextChunk(
                  Result.getAllocator().CopyString(Record->getNameAsString()));
    if (ClassTemplateDecl *Template = Record->getDescribedClassTemplate()) {
      Result.AddChunk(CodeCompletionString::CK_LeftAngle);
      AddTemplateParameterChunks(Context, Policy, Template, Result);
      Result.AddChunk(CodeCompletionString::CK_RightAngle);
    }
    break;
  }
  }
}

CodeCompletionString *CodeCompletionResult::CreateCodeCompletionString(Sema &S,
                                         CodeCompletionAllocator &Allocator,
                                         CodeCompletionTUInfo &CCTUInfo,
                                         bool IncludeBriefComments) {
  return CreateCodeCompletionString(S.Context, S.PP, Allocator, CCTUInfo,
                                    IncludeBriefComments);
}

/// \brief If possible, create a new code completion string for the given
/// result.
///
/// \returns Either a new, heap-allocated code completion string describing
/// how to use this result, or NULL to indicate that the string or name of the
/// result is all that is needed.
CodeCompletionString *
CodeCompletionResult::CreateCodeCompletionString(ASTContext &Ctx,
                                                 Preprocessor &PP,
                                           CodeCompletionAllocator &Allocator,
                                           CodeCompletionTUInfo &CCTUInfo,
                                           bool IncludeBriefComments) {
  CodeCompletionBuilder Result(Allocator, CCTUInfo, Priority, Availability);

  PrintingPolicy Policy = getCompletionPrintingPolicy(Ctx, PP);
  if (Kind == RK_Pattern) {
    Pattern->Priority = Priority;
    Pattern->Availability = Availability;

    if (Declaration) {
      Result.addParentContext(Declaration->getDeclContext());
      Pattern->ParentName = Result.getParentName();
      // Provide code completion comment for self.GetterName where
      // GetterName is the getter method for a property with name
      // different from the property name (declared via a property
      // getter attribute.
      const NamedDecl *ND = Declaration;
      if (const ObjCMethodDecl *M = dyn_cast<ObjCMethodDecl>(ND))
        if (M->isPropertyAccessor())
          if (const ObjCPropertyDecl *PDecl = M->findPropertyDecl())
            if (PDecl->getGetterName() == M->getSelector() &&
                PDecl->getIdentifier() != M->getIdentifier()) {
              if (const RawComment *RC =
                    Ctx.getRawCommentForAnyRedecl(M)) {
                Result.addBriefComment(RC->getBriefText(Ctx));
                Pattern->BriefComment = Result.getBriefComment();
              }
              else if (const RawComment *RC =
                         Ctx.getRawCommentForAnyRedecl(PDecl)) {
                Result.addBriefComment(RC->getBriefText(Ctx));
                Pattern->BriefComment = Result.getBriefComment();
              }
            }
    }

    return Pattern;
  }

  if (Kind == RK_Keyword) {
    Result.AddTypedTextChunk(Keyword);
    return Result.TakeString();
  }

  if (Kind == RK_Macro) {
    const MacroDirective *MD = PP.getMacroDirectiveHistory(Macro);
    assert(MD && "Not a macro?");
    const MacroInfo *MI = MD->getMacroInfo();

    Result.AddTypedTextChunk(
                            Result.getAllocator().CopyString(Macro->getName()));

    if (!MI->isFunctionLike())
      return Result.TakeString();

    // Format a function-like macro with placeholders for the arguments.
    Result.AddChunk(CodeCompletionString::CK_LeftParen);
    MacroInfo::arg_iterator A = MI->arg_begin(), AEnd = MI->arg_end();

    // C99 variadic macros add __VA_ARGS__ at the end. Skip it.
    if (MI->isC99Varargs()) {
      --AEnd;

      if (A == AEnd) {
        Result.AddPlaceholderChunk("...");
      }
    }

    for (MacroInfo::arg_iterator A = MI->arg_begin(); A != AEnd; ++A) {
      if (A != MI->arg_begin())
        Result.AddChunk(CodeCompletionString::CK_Comma);

      if (MI->isVariadic() && (A+1) == AEnd) {
        SmallString<32> Arg = (*A)->getName();
        if (MI->isC99Varargs())
          Arg += ", ...";
        else
          Arg += "...";
        Result.AddPlaceholderChunk(Result.getAllocator().CopyString(Arg));
        break;
      }

      // Non-variadic macros are simple.
      Result.AddPlaceholderChunk(
                          Result.getAllocator().CopyString((*A)->getName()));
    }
    Result.AddChunk(CodeCompletionString::CK_RightParen);
    return Result.TakeString();
  }

  assert(Kind == RK_Declaration && "Missed a result kind?");
  const NamedDecl *ND = Declaration;
  Result.addParentContext(ND->getDeclContext());

  if (IncludeBriefComments) {
    // Add documentation comment, if it exists.
    if (const RawComment *RC = Ctx.getRawCommentForAnyRedecl(ND)) {
      Result.addBriefComment(RC->getBriefText(Ctx));
    }
    else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(ND))
      if (OMD->isPropertyAccessor())
        if (const ObjCPropertyDecl *PDecl = OMD->findPropertyDecl())
          if (const RawComment *RC = Ctx.getRawCommentForAnyRedecl(PDecl))
            Result.addBriefComment(RC->getBriefText(Ctx));
  }

  if (StartsNestedNameSpecifier) {
    Result.AddTypedTextChunk(
                      Result.getAllocator().CopyString(ND->getNameAsString()));
    Result.AddTextChunk("::");
    return Result.TakeString();
  }

  for (Decl::attr_iterator i = ND->attr_begin(); i != ND->attr_end(); ++i) {
    if (AnnotateAttr *Attr = dyn_cast_or_null<AnnotateAttr>(*i)) {
      Result.AddAnnotation(Result.getAllocator().CopyString(Attr->getAnnotation()));
    }
  }

  AddResultTypeChunk(Ctx, Policy, ND, Result);

  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(ND)) {
    AddQualifierToCompletionString(Result, Qualifier, QualifierIsInformative,
                                   Ctx, Policy);
    AddTypedNameChunk(Ctx, Policy, ND, Result);
    Result.AddChunk(CodeCompletionString::CK_LeftParen);
    AddFunctionParameterChunks(Ctx, Policy, Function, Result);
    Result.AddChunk(CodeCompletionString::CK_RightParen);
    AddFunctionTypeQualsToCompletionString(Result, Function);
    return Result.TakeString();
  }

  if (const FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(ND)) {
    AddQualifierToCompletionString(Result, Qualifier, QualifierIsInformative,
                                   Ctx, Policy);
    FunctionDecl *Function = FunTmpl->getTemplatedDecl();
    AddTypedNameChunk(Ctx, Policy, Function, Result);

    // Figure out which template parameters are deduced (or have default
    // arguments).
    llvm::SmallBitVector Deduced;
    Sema::MarkDeducedTemplateParameters(Ctx, FunTmpl, Deduced);
    unsigned LastDeducibleArgument;
    for (LastDeducibleArgument = Deduced.size(); LastDeducibleArgument > 0;
         --LastDeducibleArgument) {
      if (!Deduced[LastDeducibleArgument - 1]) {
        // C++0x: Figure out if the template argument has a default. If so,
        // the user doesn't need to type this argument.
        // FIXME: We need to abstract template parameters better!
        bool HasDefaultArg = false;
        NamedDecl *Param = FunTmpl->getTemplateParameters()->getParam(
                                                    LastDeducibleArgument - 1);
        if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
          HasDefaultArg = TTP->hasDefaultArgument();
        else if (NonTypeTemplateParmDecl *NTTP
                 = dyn_cast<NonTypeTemplateParmDecl>(Param))
          HasDefaultArg = NTTP->hasDefaultArgument();
        else {
          assert(isa<TemplateTemplateParmDecl>(Param));
          HasDefaultArg
            = cast<TemplateTemplateParmDecl>(Param)->hasDefaultArgument();
        }

        if (!HasDefaultArg)
          break;
      }
    }

    if (LastDeducibleArgument) {
      // Some of the function template arguments cannot be deduced from a
      // function call, so we introduce an explicit template argument list
      // containing all of the arguments up to the first deducible argument.
      Result.AddChunk(CodeCompletionString::CK_LeftAngle);
      AddTemplateParameterChunks(Ctx, Policy, FunTmpl, Result,
                                 LastDeducibleArgument);
      Result.AddChunk(CodeCompletionString::CK_RightAngle);
    }

    // Add the function parameters
    Result.AddChunk(CodeCompletionString::CK_LeftParen);
    AddFunctionParameterChunks(Ctx, Policy, Function, Result);
    Result.AddChunk(CodeCompletionString::CK_RightParen);
    AddFunctionTypeQualsToCompletionString(Result, Function);
    return Result.TakeString();
  }

  if (const TemplateDecl *Template = dyn_cast<TemplateDecl>(ND)) {
    AddQualifierToCompletionString(Result, Qualifier, QualifierIsInformative,
                                   Ctx, Policy);
    Result.AddTypedTextChunk(
                Result.getAllocator().CopyString(Template->getNameAsString()));
    Result.AddChunk(CodeCompletionString::CK_LeftAngle);
    AddTemplateParameterChunks(Ctx, Policy, Template, Result);
    Result.AddChunk(CodeCompletionString::CK_RightAngle);
    return Result.TakeString();
  }

  if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(ND)) {
    Selector Sel = Method->getSelector();
    if (Sel.isUnarySelector()) {
      Result.AddTypedTextChunk(Result.getAllocator().CopyString(
                                  Sel.getNameForSlot(0)));
      return Result.TakeString();
    }

    std::string SelName = Sel.getNameForSlot(0).str();
    SelName += ':';
    if (StartParameter == 0)
      Result.AddTypedTextChunk(Result.getAllocator().CopyString(SelName));
    else {
      Result.AddInformativeChunk(Result.getAllocator().CopyString(SelName));

      // If there is only one parameter, and we're past it, add an empty
      // typed-text chunk since there is nothing to type.
      if (Method->param_size() == 1)
        Result.AddTypedTextChunk("");
    }
    unsigned Idx = 0;
    for (ObjCMethodDecl::param_const_iterator P = Method->param_begin(),
                                           PEnd = Method->param_end();
         P != PEnd; (void)++P, ++Idx) {
      if (Idx > 0) {
        std::string Keyword;
        if (Idx > StartParameter)
          Result.AddChunk(CodeCompletionString::CK_HorizontalSpace);
        if (IdentifierInfo *II = Sel.getIdentifierInfoForSlot(Idx))
          Keyword += II->getName();
        Keyword += ":";
        if (Idx < StartParameter || AllParametersAreInformative)
          Result.AddInformativeChunk(Result.getAllocator().CopyString(Keyword));
        else
          Result.AddTypedTextChunk(Result.getAllocator().CopyString(Keyword));
      }

      // If we're before the starting parameter, skip the placeholder.
      if (Idx < StartParameter)
        continue;

      std::string Arg;

      if ((*P)->getType()->isBlockPointerType() && !DeclaringEntity)
        Arg = FormatFunctionParameter(Ctx, Policy, *P, true);
      else {
        (*P)->getType().getAsStringInternal(Arg, Policy);
        Arg = "(" + formatObjCParamQualifiers((*P)->getObjCDeclQualifier())
            + Arg + ")";
        if (IdentifierInfo *II = (*P)->getIdentifier())
          if (DeclaringEntity || AllParametersAreInformative)
            Arg += II->getName();
      }

      if (Method->isVariadic() && (P + 1) == PEnd)
        Arg += ", ...";

      if (DeclaringEntity)
        Result.AddTextChunk(Result.getAllocator().CopyString(Arg));
      else if (AllParametersAreInformative)
        Result.AddInformativeChunk(Result.getAllocator().CopyString(Arg));
      else
        Result.AddPlaceholderChunk(Result.getAllocator().CopyString(Arg));
    }

    if (Method->isVariadic()) {
      if (Method->param_size() == 0) {
        if (DeclaringEntity)
          Result.AddTextChunk(", ...");
        else if (AllParametersAreInformative)
          Result.AddInformativeChunk(", ...");
        else
          Result.AddPlaceholderChunk(", ...");
      }

      MaybeAddSentinel(Ctx, Method, Result);
    }

    return Result.TakeString();
  }

  if (Qualifier)
    AddQualifierToCompletionString(Result, Qualifier, QualifierIsInformative,
                                   Ctx, Policy);

  Result.AddTypedTextChunk(
                       Result.getAllocator().CopyString(ND->getNameAsString()));
  return Result.TakeString();
}

CodeCompletionString *
CodeCompleteConsumer::OverloadCandidate::CreateSignatureString(
                                                          unsigned CurrentArg,
                                                               Sema &S,
                                     CodeCompletionAllocator &Allocator,
                                     CodeCompletionTUInfo &CCTUInfo) const {
  PrintingPolicy Policy = getCompletionPrintingPolicy(S);

  // FIXME: Set priority, availability appropriately.
  CodeCompletionBuilder Result(Allocator,CCTUInfo, 1, CXAvailability_Available);
  FunctionDecl *FDecl = getFunction();
  AddResultTypeChunk(S.Context, Policy, FDecl, Result);
  const FunctionProtoType *Proto
    = dyn_cast<FunctionProtoType>(getFunctionType());
  if (!FDecl && !Proto) {
    // Function without a prototype. Just give the return type and a
    // highlighted ellipsis.
    const FunctionType *FT = getFunctionType();
    Result.AddTextChunk(GetCompletionTypeString(FT->getResultType(),
                                                S.Context, Policy,
                                                Result.getAllocator()));
    Result.AddChunk(CodeCompletionString::CK_LeftParen);
    Result.AddChunk(CodeCompletionString::CK_CurrentParameter, "...");
    Result.AddChunk(CodeCompletionString::CK_RightParen);
    return Result.TakeString();
  }

  if (FDecl)
    Result.AddTextChunk(
                    Result.getAllocator().CopyString(FDecl->getNameAsString()));
  else
    Result.AddTextChunk(
         Result.getAllocator().CopyString(
                                  Proto->getResultType().getAsString(Policy)));

  Result.AddChunk(CodeCompletionString::CK_LeftParen);
  unsigned NumParams = FDecl? FDecl->getNumParams() : Proto->getNumArgs();
  for (unsigned I = 0; I != NumParams; ++I) {
    if (I)
      Result.AddChunk(CodeCompletionString::CK_Comma);

    std::string ArgString;
    QualType ArgType;

    if (FDecl) {
      ArgString = FDecl->getParamDecl(I)->getNameAsString();
      ArgType = FDecl->getParamDecl(I)->getOriginalType();
    } else {
      ArgType = Proto->getArgType(I);
    }

    ArgType.getAsStringInternal(ArgString, Policy);

    if (I == CurrentArg)
      Result.AddChunk(CodeCompletionString::CK_CurrentParameter,
                      Result.getAllocator().CopyString(ArgString));
    else
      Result.AddTextChunk(Result.getAllocator().CopyString(ArgString));
  }

  if (Proto && Proto->isVariadic()) {
    Result.AddChunk(CodeCompletionString::CK_Comma);
    if (CurrentArg < NumParams)
      Result.AddTextChunk("...");
    else
      Result.AddChunk(CodeCompletionString::CK_CurrentParameter, "...");
  }
  Result.AddChunk(CodeCompletionString::CK_RightParen);

  return Result.TakeString();
}

unsigned clang::getMacroUsagePriority(StringRef MacroName,
                                      const LangOptions &LangOpts,
                                      bool PreferredTypeIsPointer) {
  unsigned Priority = CCP_Macro;

  // Treat the "nil", "Nil" and "NULL" macros as null pointer constants.
  if (MacroName.equals("nil") || MacroName.equals("NULL") ||
      MacroName.equals("Nil")) {
    Priority = CCP_Constant;
    if (PreferredTypeIsPointer)
      Priority = Priority / CCF_SimilarTypeMatch;
  }
  // Treat "YES", "NO", "true", and "false" as constants.
  else if (MacroName.equals("YES") || MacroName.equals("NO") ||
           MacroName.equals("true") || MacroName.equals("false"))
    Priority = CCP_Constant;
  // Treat "bool" as a type.
  else if (MacroName.equals("bool"))
    Priority = CCP_Type + (LangOpts.ObjC1? CCD_bool_in_ObjC : 0);


  return Priority;
}

CXCursorKind clang::getCursorKindForDecl(const Decl *D) {
  if (!D)
    return CXCursor_UnexposedDecl;

  switch (D->getKind()) {
    case Decl::Enum:               return CXCursor_EnumDecl;
    case Decl::EnumConstant:       return CXCursor_EnumConstantDecl;
    case Decl::Field:              return CXCursor_FieldDecl;
    case Decl::Function:
      return CXCursor_FunctionDecl;
    case Decl::ObjCCategory:       return CXCursor_ObjCCategoryDecl;
    case Decl::ObjCCategoryImpl:   return CXCursor_ObjCCategoryImplDecl;
    case Decl::ObjCImplementation: return CXCursor_ObjCImplementationDecl;

    case Decl::ObjCInterface:      return CXCursor_ObjCInterfaceDecl;
    case Decl::ObjCIvar:           return CXCursor_ObjCIvarDecl;
    case Decl::ObjCMethod:
      return cast<ObjCMethodDecl>(D)->isInstanceMethod()
      ? CXCursor_ObjCInstanceMethodDecl : CXCursor_ObjCClassMethodDecl;
    case Decl::CXXMethod:          return CXCursor_CXXMethod;
    case Decl::CXXConstructor:     return CXCursor_Constructor;
    case Decl::CXXDestructor:      return CXCursor_Destructor;
    case Decl::CXXConversion:      return CXCursor_ConversionFunction;
    case Decl::ObjCProperty:       return CXCursor_ObjCPropertyDecl;
    case Decl::ObjCProtocol:       return CXCursor_ObjCProtocolDecl;
    case Decl::ParmVar:            return CXCursor_ParmDecl;
    case Decl::Typedef:            return CXCursor_TypedefDecl;
    case Decl::TypeAlias:          return CXCursor_TypeAliasDecl;
    case Decl::Var:                return CXCursor_VarDecl;
    case Decl::Namespace:          return CXCursor_Namespace;
    case Decl::NamespaceAlias:     return CXCursor_NamespaceAlias;
    case Decl::TemplateTypeParm:   return CXCursor_TemplateTypeParameter;
    case Decl::NonTypeTemplateParm:return CXCursor_NonTypeTemplateParameter;
    case Decl::TemplateTemplateParm:return CXCursor_TemplateTemplateParameter;
    case Decl::FunctionTemplate:   return CXCursor_FunctionTemplate;
    case Decl::ClassTemplate:      return CXCursor_ClassTemplate;
    case Decl::AccessSpec:         return CXCursor_CXXAccessSpecifier;
    case Decl::ClassTemplatePartialSpecialization:
      return CXCursor_ClassTemplatePartialSpecialization;
    case Decl::UsingDirective:     return CXCursor_UsingDirective;
    case Decl::TranslationUnit:    return CXCursor_TranslationUnit;

    case Decl::Using:
    case Decl::UnresolvedUsingValue:
    case Decl::UnresolvedUsingTypename:
      return CXCursor_UsingDeclaration;

    case Decl::ObjCPropertyImpl:
      switch (cast<ObjCPropertyImplDecl>(D)->getPropertyImplementation()) {
      case ObjCPropertyImplDecl::Dynamic:
        return CXCursor_ObjCDynamicDecl;

      case ObjCPropertyImplDecl::Synthesize:
        return CXCursor_ObjCSynthesizeDecl;
      }

      case Decl::Import:
        return CXCursor_ModuleImportDecl;

    default:
      if (const TagDecl *TD = dyn_cast<TagDecl>(D)) {
        switch (TD->getTagKind()) {
          case TTK_Interface:  // fall through
          case TTK_Struct: return CXCursor_StructDecl;
          case TTK_Class:  return CXCursor_ClassDecl;
          case TTK_Union:  return CXCursor_UnionDecl;
          case TTK_Enum:   return CXCursor_EnumDecl;
        }
      }
  }

  return CXCursor_UnexposedDecl;
}

static void AddMacroResults(Preprocessor &PP, ResultBuilder &Results,
                            bool IncludeUndefined,
                            bool TargetTypeIsPointer = false) {
  typedef CodeCompletionResult Result;

  Results.EnterNewScope();

  for (Preprocessor::macro_iterator M = PP.macro_begin(),
                                 MEnd = PP.macro_end();
       M != MEnd; ++M) {
    if (IncludeUndefined || M->first->hasMacroDefinition())
      Results.AddResult(Result(M->first,
                             getMacroUsagePriority(M->first->getName(),
                                                   PP.getLangOpts(),
                                                   TargetTypeIsPointer)));
  }

  Results.ExitScope();

}

static void AddPrettyFunctionResults(const LangOptions &LangOpts,
                                     ResultBuilder &Results) {
  typedef CodeCompletionResult Result;

  Results.EnterNewScope();

  Results.AddResult(Result("__PRETTY_FUNCTION__", CCP_Constant));
  Results.AddResult(Result("__FUNCTION__", CCP_Constant));
  if (LangOpts.C99 || LangOpts.CPlusPlus11)
    Results.AddResult(Result("__func__", CCP_Constant));
  Results.ExitScope();
}

static void HandleCodeCompleteResults(Sema *S,
                                      CodeCompleteConsumer *CodeCompleter,
                                      CodeCompletionContext Context,
                                      CodeCompletionResult *Results,
                                      unsigned NumResults) {
  if (CodeCompleter)
    CodeCompleter->ProcessCodeCompleteResults(*S, Context, Results, NumResults);
}

static enum CodeCompletionContext::Kind mapCodeCompletionContext(Sema &S,
                                            Sema::ParserCompletionContext PCC) {
  switch (PCC) {
  case Sema::PCC_Namespace:
    return CodeCompletionContext::CCC_TopLevel;

  case Sema::PCC_Class:
    return CodeCompletionContext::CCC_ClassStructUnion;

  case Sema::PCC_ObjCInterface:
    return CodeCompletionContext::CCC_ObjCInterface;

  case Sema::PCC_ObjCImplementation:
    return CodeCompletionContext::CCC_ObjCImplementation;

  case Sema::PCC_ObjCInstanceVariableList:
    return CodeCompletionContext::CCC_ObjCIvarList;

  case Sema::PCC_Template:
  case Sema::PCC_MemberTemplate:
    if (S.CurContext->isFileContext())
      return CodeCompletionContext::CCC_TopLevel;
    if (S.CurContext->isRecord())
      return CodeCompletionContext::CCC_ClassStructUnion;
    return CodeCompletionContext::CCC_Other;

  case Sema::PCC_RecoveryInFunction:
    return CodeCompletionContext::CCC_Recovery;

  case Sema::PCC_ForInit:
    if (S.getLangOpts().CPlusPlus || S.getLangOpts().C99 ||
        S.getLangOpts().ObjC1)
      return CodeCompletionContext::CCC_ParenthesizedExpression;
    else
      return CodeCompletionContext::CCC_Expression;

  case Sema::PCC_Expression:
  case Sema::PCC_Condition:
    return CodeCompletionContext::CCC_Expression;

  case Sema::PCC_Statement:
    return CodeCompletionContext::CCC_Statement;

  case Sema::PCC_Type:
    return CodeCompletionContext::CCC_Type;

  case Sema::PCC_ParenthesizedExpression:
    return CodeCompletionContext::CCC_ParenthesizedExpression;

  case Sema::PCC_LocalDeclarationSpecifiers:
    return CodeCompletionContext::CCC_Type;
  }

  llvm_unreachable("Invalid ParserCompletionContext!");
}

/// \brief If we're in a C++ virtual member function, add completion results
/// that invoke the functions we override, since it's common to invoke the
/// overridden function as well as adding new functionality.
///
/// \param S The semantic analysis object for which we are generating results.
///
/// \param InContext This context in which the nested-name-specifier preceding
/// the code-completion point
static void MaybeAddOverrideCalls(Sema &S, DeclContext *InContext,
                                  ResultBuilder &Results) {
  // Look through blocks.
  DeclContext *CurContext = S.CurContext;
  while (isa<BlockDecl>(CurContext))
    CurContext = CurContext->getParent();


  CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(CurContext);
  if (!Method || !Method->isVirtual())
    return;

  // We need to have names for all of the parameters, if we're going to
  // generate a forwarding call.
  for (CXXMethodDecl::param_iterator P = Method->param_begin(),
                                  PEnd = Method->param_end();
       P != PEnd;
       ++P) {
    if (!(*P)->getDeclName())
      return;
  }

  PrintingPolicy Policy = getCompletionPrintingPolicy(S);
  for (CXXMethodDecl::method_iterator M = Method->begin_overridden_methods(),
                                   MEnd = Method->end_overridden_methods();
       M != MEnd; ++M) {
    CodeCompletionBuilder Builder(Results.getAllocator(),
                                  Results.getCodeCompletionTUInfo());
    const CXXMethodDecl *Overridden = *M;
    if (Overridden->getCanonicalDecl() == Method->getCanonicalDecl())
      continue;

    // If we need a nested-name-specifier, add one now.
    if (!InContext) {
      NestedNameSpecifier *NNS
        = getRequiredQualification(S.Context, CurContext,
                                   Overridden->getDeclContext());
      if (NNS) {
        std::string Str;
        llvm::raw_string_ostream OS(Str);
        NNS->print(OS, Policy);
        Builder.AddTextChunk(Results.getAllocator().CopyString(OS.str()));
      }
    } else if (!InContext->Equals(Overridden->getDeclContext()))
      continue;

    Builder.AddTypedTextChunk(Results.getAllocator().CopyString(
                                         Overridden->getNameAsString()));
    Builder.AddChunk(CodeCompletionString::CK_LeftParen);
    bool FirstParam = true;
    for (CXXMethodDecl::param_iterator P = Method->param_begin(),
                                    PEnd = Method->param_end();
         P != PEnd; ++P) {
      if (FirstParam)
        FirstParam = false;
      else
        Builder.AddChunk(CodeCompletionString::CK_Comma);

      Builder.AddPlaceholderChunk(Results.getAllocator().CopyString(
                                        (*P)->getIdentifier()->getName()));
    }
    Builder.AddChunk(CodeCompletionString::CK_RightParen);
    Results.AddResult(CodeCompletionResult(Builder.TakeString(),
                                           CCP_SuperCompletion,
                                           CXCursor_CXXMethod,
                                           CXAvailability_Available,
                                           Overridden));
    Results.Ignore(Overridden);
  }
}

void Sema::CodeCompleteModuleImport(SourceLocation ImportLoc,
                                    ModuleIdPath Path) {
  typedef CodeCompletionResult Result;
  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(),
                        CodeCompletionContext::CCC_Other);
  Results.EnterNewScope();

  CodeCompletionAllocator &Allocator = Results.getAllocator();
  CodeCompletionBuilder Builder(Allocator, Results.getCodeCompletionTUInfo());
  typedef CodeCompletionResult Result;
  if (Path.empty()) {
    // Enumerate all top-level modules.
    SmallVector<Module *, 8> Modules;
    PP.getHeaderSearchInfo().collectAllModules(Modules);
    for (unsigned I = 0, N = Modules.size(); I != N; ++I) {
      Builder.AddTypedTextChunk(
        Builder.getAllocator().CopyString(Modules[I]->Name));
      Results.AddResult(Result(Builder.TakeString(),
                               CCP_Declaration,
                               CXCursor_ModuleImportDecl,
                               Modules[I]->isAvailable()
                                 ? CXAvailability_Available
                                  : CXAvailability_NotAvailable));
    }
  } else if (getLangOpts().Modules) {
    // Load the named module.
    Module *Mod = PP.getModuleLoader().loadModule(ImportLoc, Path,
                                                  Module::AllVisible,
                                                /*IsInclusionDirective=*/false);
    // Enumerate submodules.
    if (Mod) {
      for (Module::submodule_iterator Sub = Mod->submodule_begin(),
                                   SubEnd = Mod->submodule_end();
           Sub != SubEnd; ++Sub) {

        Builder.AddTypedTextChunk(
          Builder.getAllocator().CopyString((*Sub)->Name));
        Results.AddResult(Result(Builder.TakeString(),
                                 CCP_Declaration,
                                 CXCursor_ModuleImportDecl,
                                 (*Sub)->isAvailable()
                                   ? CXAvailability_Available
                                   : CXAvailability_NotAvailable));
      }
    }
  }
  Results.ExitScope();
  HandleCodeCompleteResults(this, CodeCompleter, Results.getCompletionContext(),
                            Results.data(),Results.size());
}

void Sema::CodeCompleteOrdinaryName(Scope *S,
                                    ParserCompletionContext CompletionContext) {
  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(),
                        mapCodeCompletionContext(*this, CompletionContext));
  Results.EnterNewScope();

  // Determine how to filter results, e.g., so that the names of
  // values (functions, enumerators, function templates, etc.) are
  // only allowed where we can have an expression.
  switch (CompletionContext) {
  case PCC_Namespace:
  case PCC_Class:
  case PCC_ObjCInterface:
  case PCC_ObjCImplementation:
  case PCC_ObjCInstanceVariableList:
  case PCC_Template:
  case PCC_MemberTemplate:
  case PCC_Type:
  case PCC_LocalDeclarationSpecifiers:
    Results.setFilter(&ResultBuilder::IsOrdinaryNonValueName);
    break;

  case PCC_Statement:
  case PCC_ParenthesizedExpression:
  case PCC_Expression:
  case PCC_ForInit:
  case PCC_Condition:
    if (WantTypesInContext(CompletionContext, getLangOpts()))
      Results.setFilter(&ResultBuilder::IsOrdinaryName);
    else
      Results.setFilter(&ResultBuilder::IsOrdinaryNonTypeName);

    if (getLangOpts().CPlusPlus)
      MaybeAddOverrideCalls(*this, /*InContext=*/0, Results);
    break;

  case PCC_RecoveryInFunction:
    // Unfiltered
    break;
  }

  // If we are in a C++ non-static member function, check the qualifiers on
  // the member function to filter/prioritize the results list.
  if (CXXMethodDecl *CurMethod = dyn_cast<CXXMethodDecl>(CurContext))
    if (CurMethod->isInstance())
      Results.setObjectTypeQualifiers(
                      Qualifiers::fromCVRMask(CurMethod->getTypeQualifiers()));

  CodeCompletionDeclConsumer Consumer(Results, CurContext);
  LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
                     CodeCompleter->includeGlobals());

  AddOrdinaryNameResults(CompletionContext, S, *this, Results);
  Results.ExitScope();

  switch (CompletionContext) {
  case PCC_ParenthesizedExpression:
  case PCC_Expression:
  case PCC_Statement:
  case PCC_RecoveryInFunction:
    if (S->getFnParent())
      AddPrettyFunctionResults(PP.getLangOpts(), Results);
    break;

  case PCC_Namespace:
  case PCC_Class:
  case PCC_ObjCInterface:
  case PCC_ObjCImplementation:
  case PCC_ObjCInstanceVariableList:
  case PCC_Template:
  case PCC_MemberTemplate:
  case PCC_ForInit:
  case PCC_Condition:
  case PCC_Type:
  case PCC_LocalDeclarationSpecifiers:
    break;
  }

  if (CodeCompleter->includeMacros())
    AddMacroResults(PP, Results, false);

  HandleCodeCompleteResults(this, CodeCompleter, Results.getCompletionContext(),
                            Results.data(),Results.size());
}

static void AddClassMessageCompletions(Sema &SemaRef, Scope *S,
                                       ParsedType Receiver,
                                       ArrayRef<IdentifierInfo *> SelIdents,
                                       bool AtArgumentExpression,
                                       bool IsSuper,
                                       ResultBuilder &Results);

void Sema::CodeCompleteDeclSpec(Scope *S, DeclSpec &DS,
                                bool AllowNonIdentifiers,
                                bool AllowNestedNameSpecifiers) {
  typedef CodeCompletionResult Result;
  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(),
                        AllowNestedNameSpecifiers
                          ? CodeCompletionContext::CCC_PotentiallyQualifiedName
                          : CodeCompletionContext::CCC_Name);
  Results.EnterNewScope();

  // Type qualifiers can come after names.
  Results.AddResult(Result("const"));
  Results.AddResult(Result("volatile"));
  if (getLangOpts().C99)
    Results.AddResult(Result("restrict"));

  if (getLangOpts().CPlusPlus) {
    if (AllowNonIdentifiers) {
      Results.AddResult(Result("operator"));
    }

    // Add nested-name-specifiers.
    if (AllowNestedNameSpecifiers) {
      Results.allowNestedNameSpecifiers();
      Results.setFilter(&ResultBuilder::IsImpossibleToSatisfy);
      CodeCompletionDeclConsumer Consumer(Results, CurContext);
      LookupVisibleDecls(S, LookupNestedNameSpecifierName, Consumer,
                         CodeCompleter->includeGlobals());
      Results.setFilter(0);
    }
  }
  Results.ExitScope();

  // If we're in a context where we might have an expression (rather than a
  // declaration), and what we've seen so far is an Objective-C type that could
  // be a receiver of a class message, this may be a class message send with
  // the initial opening bracket '[' missing. Add appropriate completions.
  if (AllowNonIdentifiers && !AllowNestedNameSpecifiers &&
      DS.getParsedSpecifiers() == DeclSpec::PQ_TypeSpecifier &&
      DS.getTypeSpecType() == DeclSpec::TST_typename &&
      DS.getTypeSpecComplex() == DeclSpec::TSC_unspecified &&
      DS.getTypeSpecSign() == DeclSpec::TSS_unspecified &&
      !DS.isTypeAltiVecVector() &&
      S &&
      (S->getFlags() & Scope::DeclScope) != 0 &&
      (S->getFlags() & (Scope::ClassScope | Scope::TemplateParamScope |
                        Scope::FunctionPrototypeScope |
                        Scope::AtCatchScope)) == 0) {
    ParsedType T = DS.getRepAsType();
    if (!T.get().isNull() && T.get()->isObjCObjectOrInterfaceType())
      AddClassMessageCompletions(*this, S, T, None, false, false, Results);
  }

  // Note that we intentionally suppress macro results here, since we do not
  // encourage using macros to produce the names of entities.

  HandleCodeCompleteResults(this, CodeCompleter,
                            Results.getCompletionContext(),
                            Results.data(), Results.size());
}

struct Sema::CodeCompleteExpressionData {
  CodeCompleteExpressionData(QualType PreferredType = QualType())
    : PreferredType(PreferredType), IntegralConstantExpression(false),
      ObjCCollection(false) { }

  QualType PreferredType;
  bool IntegralConstantExpression;
  bool ObjCCollection;
  SmallVector<Decl *, 4> IgnoreDecls;
};

/// \brief Perform code-completion in an expression context when we know what
/// type we're looking for.
void Sema::CodeCompleteExpression(Scope *S,
                                  const CodeCompleteExpressionData &Data) {
  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(),
                        CodeCompletionContext::CCC_Expression);
  if (Data.ObjCCollection)
    Results.setFilter(&ResultBuilder::IsObjCCollection);
  else if (Data.IntegralConstantExpression)
    Results.setFilter(&ResultBuilder::IsIntegralConstantValue);
  else if (WantTypesInContext(PCC_Expression, getLangOpts()))
    Results.setFilter(&ResultBuilder::IsOrdinaryName);
  else
    Results.setFilter(&ResultBuilder::IsOrdinaryNonTypeName);

  if (!Data.PreferredType.isNull())
    Results.setPreferredType(Data.PreferredType.getNonReferenceType());

  // Ignore any declarations that we were told that we don't care about.
  for (unsigned I = 0, N = Data.IgnoreDecls.size(); I != N; ++I)
    Results.Ignore(Data.IgnoreDecls[I]);

  CodeCompletionDeclConsumer Consumer(Results, CurContext);
  LookupVisibleDecls(S, LookupOrdinaryName, Consumer,
                     CodeCompleter->includeGlobals());

  Results.EnterNewScope();
  AddOrdinaryNameResults(PCC_Expression, S, *this, Results);
  Results.ExitScope();

  bool PreferredTypeIsPointer = false;
  if (!Data.PreferredType.isNull())
    PreferredTypeIsPointer = Data.PreferredType->isAnyPointerType()
      || Data.PreferredType->isMemberPointerType()
      || Data.PreferredType->isBlockPointerType();

  if (S->getFnParent() &&
      !Data.ObjCCollection &&
      !Data.IntegralConstantExpression)
    AddPrettyFunctionResults(PP.getLangOpts(), Results);

  if (CodeCompleter->includeMacros())
    AddMacroResults(PP, Results, false, PreferredTypeIsPointer);
  HandleCodeCompleteResults(this, CodeCompleter,
                CodeCompletionContext(CodeCompletionContext::CCC_Expression,
                                      Data.PreferredType),
                            Results.data(),Results.size());
}

void Sema::CodeCompletePostfixExpression(Scope *S, ExprResult E) {
  if (E.isInvalid())
    CodeCompleteOrdinaryName(S, PCC_RecoveryInFunction);
  else if (getLangOpts().ObjC1)
    CodeCompleteObjCInstanceMessage(S, E.take(), None, false);
}

/// \brief The set of properties that have already been added, referenced by
/// property name.
typedef llvm::SmallPtrSet<IdentifierInfo*, 16> AddedPropertiesSet;

/// \brief Retrieve the container definition, if any?
static ObjCContainerDecl *getContainerDef(ObjCContainerDecl *Container) {
  if (ObjCInterfaceDecl *Interface = dyn_cast<ObjCInterfaceDecl>(Container)) {
    if (Interface->hasDefinition())
      return Interface->getDefinition();

    return Interface;
  }

  if (ObjCProtocolDecl *Protocol = dyn_cast<ObjCProtocolDecl>(Container)) {
    if (Protocol->hasDefinition())
      return Protocol->getDefinition();

    return Protocol;
  }
  return Container;
}

static void AddObjCProperties(ObjCContainerDecl *Container,
                              bool AllowCategories,
                              bool AllowNullaryMethods,
                              DeclContext *CurContext,
                              AddedPropertiesSet &AddedProperties,
                              ResultBuilder &Results) {
  typedef CodeCompletionResult Result;

  // Retrieve the definition.
  Container = getContainerDef(Container);

  // Add properties in this container.
  for (ObjCContainerDecl::prop_iterator P = Container->prop_begin(),
                                     PEnd = Container->prop_end();
       P != PEnd;
       ++P) {
    if (AddedProperties.insert(P->getIdentifier()))
      Results.MaybeAddResult(Result(*P, Results.getBasePriority(*P), 0),
                             CurContext);
  }

  // Add nullary methods
  if (AllowNullaryMethods) {
    ASTContext &Context = Container->getASTContext();
    PrintingPolicy Policy = getCompletionPrintingPolicy(Results.getSema());
    for (ObjCContainerDecl::method_iterator M = Container->meth_begin(),
                                         MEnd = Container->meth_end();
         M != MEnd; ++M) {
      if (M->getSelector().isUnarySelector())
        if (IdentifierInfo *Name = M->getSelector().getIdentifierInfoForSlot(0))
          if (AddedProperties.insert(Name)) {
            CodeCompletionBuilder Builder(Results.getAllocator(),
                                          Results.getCodeCompletionTUInfo());
            AddResultTypeChunk(Context, Policy, *M, Builder);
            Builder.AddTypedTextChunk(
                            Results.getAllocator().CopyString(Name->getName()));

            Results.MaybeAddResult(Result(Builder.TakeString(), *M,
                                  CCP_MemberDeclaration + CCD_MethodAsProperty),
                                          CurContext);
          }
    }
  }


  // Add properties in referenced protocols.
  if (ObjCProtocolDecl *Protocol = dyn_cast<ObjCProtocolDecl>(Container)) {
    for (ObjCProtocolDecl::protocol_iterator P = Protocol->protocol_begin(),
                                          PEnd = Protocol->protocol_end();
         P != PEnd; ++P)
      AddObjCProperties(*P, AllowCategories, AllowNullaryMethods, CurContext,
                        AddedProperties, Results);
  } else if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(Container)){
    if (AllowCategories) {
      // Look through categories.
      for (ObjCInterfaceDecl::known_categories_iterator
             Cat = IFace->known_categories_begin(),
             CatEnd = IFace->known_categories_end();
           Cat != CatEnd; ++Cat)
        AddObjCProperties(*Cat, AllowCategories, AllowNullaryMethods,
                          CurContext, AddedProperties, Results);
    }

    // Look through protocols.
    for (ObjCInterfaceDecl::all_protocol_iterator
         I = IFace->all_referenced_protocol_begin(),
         E = IFace->all_referenced_protocol_end(); I != E; ++I)
      AddObjCProperties(*I, AllowCategories, AllowNullaryMethods, CurContext,
                        AddedProperties, Results);

    // Look in the superclass.
    if (IFace->getSuperClass())
      AddObjCProperties(IFace->getSuperClass(), AllowCategories,
                        AllowNullaryMethods, CurContext,
                        AddedProperties, Results);
  } else if (const ObjCCategoryDecl *Category
                                    = dyn_cast<ObjCCategoryDecl>(Container)) {
    // Look through protocols.
    for (ObjCCategoryDecl::protocol_iterator P = Category->protocol_begin(),
                                          PEnd = Category->protocol_end();
         P != PEnd; ++P)
      AddObjCProperties(*P, AllowCategories, AllowNullaryMethods, CurContext,
                        AddedProperties, Results);
  }
}

void Sema::CodeCompleteMemberReferenceExpr(Scope *S, Expr *Base,
                                           SourceLocation OpLoc,
                                           bool IsArrow) {
  if (!Base || !CodeCompleter)
    return;

  ExprResult ConvertedBase = PerformMemberExprBaseConversion(Base, IsArrow);
  if (ConvertedBase.isInvalid())
    return;
  Base = ConvertedBase.get();

  typedef CodeCompletionResult Result;

  QualType BaseType = Base->getType();

  if (IsArrow) {
    if (const PointerType *Ptr = BaseType->getAs<PointerType>())
      BaseType = Ptr->getPointeeType();
    else if (BaseType->isObjCObjectPointerType())
      /*Do nothing*/ ;
    else
      return;
  }

  enum CodeCompletionContext::Kind contextKind;

  if (IsArrow) {
    contextKind = CodeCompletionContext::CCC_ArrowMemberAccess;
  }
  else {
    if (BaseType->isObjCObjectPointerType() ||
        BaseType->isObjCObjectOrInterfaceType()) {
      contextKind = CodeCompletionContext::CCC_ObjCPropertyAccess;
    }
    else {
      contextKind = CodeCompletionContext::CCC_DotMemberAccess;
    }
  }

  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(),
                  CodeCompletionContext(contextKind,
                                        BaseType),
                        &ResultBuilder::IsMember);
  Results.EnterNewScope();
  if (const RecordType *Record = BaseType->getAs<RecordType>()) {
    // Indicate that we are performing a member access, and the cv-qualifiers
    // for the base object type.
    Results.setObjectTypeQualifiers(BaseType.getQualifiers());

    // Access to a C/C++ class, struct, or union.
    Results.allowNestedNameSpecifiers();
    CodeCompletionDeclConsumer Consumer(Results, CurContext);
    LookupVisibleDecls(Record->getDecl(), LookupMemberName, Consumer,
                       CodeCompleter->includeGlobals());

    if (getLangOpts().CPlusPlus) {
      if (!Results.empty()) {
        // The "template" keyword can follow "->" or "." in the grammar.
        // However, we only want to suggest the template keyword if something
        // is dependent.
        bool IsDependent = BaseType->isDependentType();
        if (!IsDependent) {
          for (Scope *DepScope = S; DepScope; DepScope = DepScope->getParent())
            if (DeclContext *Ctx = (DeclContext *)DepScope->getEntity()) {
              IsDependent = Ctx->isDependentContext();
              break;
            }
        }

        if (IsDependent)
          Results.AddResult(Result("template"));
      }
    }
  } else if (!IsArrow && BaseType->getAsObjCInterfacePointerType()) {
    // Objective-C property reference.
    AddedPropertiesSet AddedProperties;

    // Add property results based on our interface.
    const ObjCObjectPointerType *ObjCPtr
      = BaseType->getAsObjCInterfacePointerType();
    assert(ObjCPtr && "Non-NULL pointer guaranteed above!");
    AddObjCProperties(ObjCPtr->getInterfaceDecl(), true,
                      /*AllowNullaryMethods=*/true, CurContext,
                      AddedProperties, Results);

    // Add properties from the protocols in a qualified interface.
    for (ObjCObjectPointerType::qual_iterator I = ObjCPtr->qual_begin(),
                                              E = ObjCPtr->qual_end();
         I != E; ++I)
      AddObjCProperties(*I, true, /*AllowNullaryMethods=*/true, CurContext,
                        AddedProperties, Results);
  } else if ((IsArrow && BaseType->isObjCObjectPointerType()) ||
             (!IsArrow && BaseType->isObjCObjectType())) {
    // Objective-C instance variable access.
    ObjCInterfaceDecl *Class = 0;
    if (const ObjCObjectPointerType *ObjCPtr
                                    = BaseType->getAs<ObjCObjectPointerType>())
      Class = ObjCPtr->getInterfaceDecl();
    else
      Class = BaseType->getAs<ObjCObjectType>()->getInterface();

    // Add all ivars from this class and its superclasses.
    if (Class) {
      CodeCompletionDeclConsumer Consumer(Results, CurContext);
      Results.setFilter(&ResultBuilder::IsObjCIvar);
      LookupVisibleDecls(Class, LookupMemberName, Consumer,
                         CodeCompleter->includeGlobals());
    }
  }

  // FIXME: How do we cope with isa?

  Results.ExitScope();

  // Hand off the results found for code completion.
  HandleCodeCompleteResults(this, CodeCompleter,
                            Results.getCompletionContext(),
                            Results.data(),Results.size());
}

void Sema::CodeCompleteTag(Scope *S, unsigned TagSpec) {
  if (!CodeCompleter)
    return;

  ResultBuilder::LookupFilter Filter = 0;
  enum CodeCompletionContext::Kind ContextKind
    = CodeCompletionContext::CCC_Other;
  switch ((DeclSpec::TST)TagSpec) {
  case DeclSpec::TST_enum:
    Filter = &ResultBuilder::IsEnum;
    ContextKind = CodeCompletionContext::CCC_EnumTag;
    break;

  case DeclSpec::TST_union:
    Filter = &ResultBuilder::IsUnion;
    ContextKind = CodeCompletionContext::CCC_UnionTag;
    break;

  case DeclSpec::TST_struct:
  case DeclSpec::TST_class:
  case DeclSpec::TST_interface:
    Filter = &ResultBuilder::IsClassOrStruct;
    ContextKind = CodeCompletionContext::CCC_ClassOrStructTag;
    break;

  default:
    llvm_unreachable("Unknown type specifier kind in CodeCompleteTag");
  }

  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(), ContextKind);
  CodeCompletionDeclConsumer Consumer(Results, CurContext);

  // First pass: look for tags.
  Results.setFilter(Filter);
  LookupVisibleDecls(S, LookupTagName, Consumer,
                     CodeCompleter->includeGlobals());

  if (CodeCompleter->includeGlobals()) {
    // Second pass: look for nested name specifiers.
    Results.setFilter(&ResultBuilder::IsNestedNameSpecifier);
    LookupVisibleDecls(S, LookupNestedNameSpecifierName, Consumer);
  }

  HandleCodeCompleteResults(this, CodeCompleter, Results.getCompletionContext(),
                            Results.data(),Results.size());
}

void Sema::CodeCompleteTypeQualifiers(DeclSpec &DS) {
  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(),
                        CodeCompletionContext::CCC_TypeQualifiers);
  Results.EnterNewScope();
  if (!(DS.getTypeQualifiers() & DeclSpec::TQ_const))
    Results.AddResult("const");
  if (!(DS.getTypeQualifiers() & DeclSpec::TQ_volatile))
    Results.AddResult("volatile");
  if (getLangOpts().C99 &&
      !(DS.getTypeQualifiers() & DeclSpec::TQ_restrict))
    Results.AddResult("restrict");
  if (getLangOpts().C11 &&
      !(DS.getTypeQualifiers() & DeclSpec::TQ_atomic))
    Results.AddResult("_Atomic");
  Results.ExitScope();
  HandleCodeCompleteResults(this, CodeCompleter,
                            Results.getCompletionContext(),
                            Results.data(), Results.size());
}

void Sema::CodeCompleteCase(Scope *S) {
  if (getCurFunction()->SwitchStack.empty() || !CodeCompleter)
    return;

  SwitchStmt *Switch = getCurFunction()->SwitchStack.back();
  QualType type = Switch->getCond()->IgnoreImplicit()->getType();
  if (!type->isEnumeralType()) {
    CodeCompleteExpressionData Data(type);
    Data.IntegralConstantExpression = true;
    CodeCompleteExpression(S, Data);
    return;
  }

  // Code-complete the cases of a switch statement over an enumeration type
  // by providing the list of
  EnumDecl *Enum = type->castAs<EnumType>()->getDecl();
  if (EnumDecl *Def = Enum->getDefinition())
    Enum = Def;

  // Determine which enumerators we have already seen in the switch statement.
  // FIXME: Ideally, we would also be able to look *past* the code-completion
  // token, in case we are code-completing in the middle of the switch and not
  // at the end. However, we aren't able to do so at the moment.
  llvm::SmallPtrSet<EnumConstantDecl *, 8> EnumeratorsSeen;
  NestedNameSpecifier *Qualifier = 0;
  for (SwitchCase *SC = Switch->getSwitchCaseList(); SC;
       SC = SC->getNextSwitchCase()) {
    CaseStmt *Case = dyn_cast<CaseStmt>(SC);
    if (!Case)
      continue;

    Expr *CaseVal = Case->getLHS()->IgnoreParenCasts();
    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CaseVal))
      if (EnumConstantDecl *Enumerator
            = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
        // We look into the AST of the case statement to determine which
        // enumerator was named. Alternatively, we could compute the value of
        // the integral constant expression, then compare it against the
        // values of each enumerator. However, value-based approach would not
        // work as well with C++ templates where enumerators declared within a
        // template are type- and value-dependent.
        EnumeratorsSeen.insert(Enumerator);

        // If this is a qualified-id, keep track of the nested-name-specifier
        // so that we can reproduce it as part of code completion, e.g.,
        //
        //   switch (TagD.getKind()) {
        //     case TagDecl::TK_enum:
        //       break;
        //     case XXX
        //
        // At the XXX, our completions are TagDecl::TK_union,
        // TagDecl::TK_struct, and TagDecl::TK_class, rather than TK_union,
        // TK_struct, and TK_class.
        Qualifier = DRE->getQualifier();
      }
  }

  if (getLangOpts().CPlusPlus && !Qualifier && EnumeratorsSeen.empty()) {
    // If there are no prior enumerators in C++, check whether we have to
    // qualify the names of the enumerators that we suggest, because they
    // may not be visible in this scope.
    Qualifier = getRequiredQualification(Context, CurContext, Enum);
  }

  // Add any enumerators that have not yet been mentioned.
  ResultBuilder Results(*this, CodeCompleter->getAllocator(),
                        CodeCompleter->getCodeCompletionTUInfo(),
                        CodeCompletionContext::CCC_Expression);
  Results.EnterNewScope();
  for (EnumDecl::enumerator_iterator E = Enum->enumerator_begin(),
                                  EEnd = Enum->enumerator_end();
       E != EEnd; ++E) {
    if (EnumeratorsSeen.count(*E))
      continue;

    CodeCompletionResult R(*E, CCP_EnumInCase, Qualifier);
    Results.AddResult(R, CurContext, 0, false);
  }
  Results.ExitScope();

  //We need to make sure we're setting the right context,
  //so only say we include macros if the code completer says we do
  enum CodeCompletionContext::Kind kind = CodeCompletionContext::CCC_Other;
  if (CodeCompleter->includeMacros()) {
    AddMacroResults(PP, Results, false);
    kind = CodeCompletionContext::CCC_OtherWithMacros;
  }

  HandleCodeCompleteResults(this, CodeCompleter,
                            kind,
                            Results.data(),Results.size());
}

namespace {
  struct IsBetterOverloadCandidate {
    Sema &S;
    SourceLocation Loc;

  public:
    explicit IsBetterOverloadCandidate(Sema &S, SourceLocation Loc)
      : S(S), Loc(Loc) { }

    bool
    operator()(const OverloadCandidate &X, const OverloadCandidate &Y) const {
      return isBetterOverloadCandidate(S, X, Y, Loc);
    }
  };
}

static bool anyNullArgument