//===--- SemaType.cpp - Semantic Analysis for Types -----------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements type-related semantic analysis.
//
//===----------------------------------------------------------------------===//

#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "clang/Basic/OpenCL.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/TypeLocVisitor.h"
#include "clang/AST/Expr.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Lookup.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/ErrorHandling.h"
using namespace clang;

/// isOmittedBlockReturnType - Return true if this declarator is missing a
/// return type because this is a omitted return type on a block literal.
static bool isOmittedBlockReturnType(const Declarator &D) {
  if (D.getContext() != Declarator::BlockLiteralContext ||
      D.getDeclSpec().hasTypeSpecifier())
    return false;

  if (D.getNumTypeObjects() == 0)
    return true;   // ^{ ... }

  if (D.getNumTypeObjects() == 1 &&
      D.getTypeObject(0).Kind == DeclaratorChunk::Function)
    return true;   // ^(int X, float Y) { ... }

  return false;
}

/// diagnoseBadTypeAttribute - Diagnoses a type attribute which
/// doesn't apply to the given type.
static void diagnoseBadTypeAttribute(Sema &S, const AttributeList &attr,
                                     QualType type) {
  bool useExpansionLoc = false;

  unsigned diagID = 0;
  switch (attr.getKind()) {
  case AttributeList::AT_ObjCGC:
    diagID = diag::warn_pointer_attribute_wrong_type;
    useExpansionLoc = true;
    break;

  case AttributeList::AT_ObjCOwnership:
    diagID = diag::warn_objc_object_attribute_wrong_type;
    useExpansionLoc = true;
    break;

  default:
    // Assume everything else was a function attribute.
    diagID = diag::warn_function_attribute_wrong_type;
    break;
  }

  SourceLocation loc = attr.getLoc();
  StringRef name = attr.getName()->getName();

  // The GC attributes are usually written with macros;  special-case them.
  if (useExpansionLoc && loc.isMacroID() && attr.getParameterName()) {
    if (attr.getParameterName()->isStr("strong")) {
      if (S.findMacroSpelling(loc, "__strong")) name = "__strong";
    } else if (attr.getParameterName()->isStr("weak")) {
      if (S.findMacroSpelling(loc, "__weak")) name = "__weak";
    }
  }

  S.Diag(loc, diagID) << name << type;
}

// objc_gc applies to Objective-C pointers or, otherwise, to the
// smallest available pointer type (i.e. 'void*' in 'void**').
#define OBJC_POINTER_TYPE_ATTRS_CASELIST \
    case AttributeList::AT_ObjCGC: \
    case AttributeList::AT_ObjCOwnership

// Function type attributes.
#define FUNCTION_TYPE_ATTRS_CASELIST \
    case AttributeList::AT_NoReturn: \
    case AttributeList::AT_CDecl: \
    case AttributeList::AT_FastCall: \
    case AttributeList::AT_StdCall: \
    case AttributeList::AT_ThisCall: \
    case AttributeList::AT_Pascal: \
    case AttributeList::AT_Regparm: \
    case AttributeList::AT_Pcs \

namespace {
  /// An object which stores processing state for the entire
  /// GetTypeForDeclarator process.
  class TypeProcessingState {
    Sema &sema;

    /// The declarator being processed.
    Declarator &declarator;

    /// The index of the declarator chunk we're currently processing.
    /// May be the total number of valid chunks, indicating the
    /// DeclSpec.
    unsigned chunkIndex;

    /// Whether there are non-trivial modifications to the decl spec.
    bool trivial;

    /// Whether we saved the attributes in the decl spec.
    bool hasSavedAttrs;

    /// The original set of attributes on the DeclSpec.
    SmallVector<AttributeList*, 2> savedAttrs;

    /// A list of attributes to diagnose the uselessness of when the
    /// processing is complete.
    SmallVector<AttributeList*, 2> ignoredTypeAttrs;

  public:
    TypeProcessingState(Sema &sema, Declarator &declarator)
      : sema(sema), declarator(declarator),
        chunkIndex(declarator.getNumTypeObjects()),
        trivial(true), hasSavedAttrs(false) {}

    Sema &getSema() const {
      return sema;
    }

    Declarator &getDeclarator() const {
      return declarator;
    }

    unsigned getCurrentChunkIndex() const {
      return chunkIndex;
    }

    void setCurrentChunkIndex(unsigned idx) {
      assert(idx <= declarator.getNumTypeObjects());
      chunkIndex = idx;
    }

    AttributeList *&getCurrentAttrListRef() const {
      assert(chunkIndex <= declarator.getNumTypeObjects());
      if (chunkIndex == declarator.getNumTypeObjects())
        return getMutableDeclSpec().getAttributes().getListRef();
      return declarator.getTypeObject(chunkIndex).getAttrListRef();
    }

    /// Save the current set of attributes on the DeclSpec.
    void saveDeclSpecAttrs() {
      // Don't try to save them multiple times.
      if (hasSavedAttrs) return;

      DeclSpec &spec = getMutableDeclSpec();
      for (AttributeList *attr = spec.getAttributes().getList(); attr;
             attr = attr->getNext())
        savedAttrs.push_back(attr);
      trivial &= savedAttrs.empty();
      hasSavedAttrs = true;
    }

    /// Record that we had nowhere to put the given type attribute.
    /// We will diagnose such attributes later.
    void addIgnoredTypeAttr(AttributeList &attr) {
      ignoredTypeAttrs.push_back(&attr);
    }

    /// Diagnose all the ignored type attributes, given that the
    /// declarator worked out to the given type.
    void diagnoseIgnoredTypeAttrs(QualType type) const {
      for (SmallVectorImpl<AttributeList*>::const_iterator
             i = ignoredTypeAttrs.begin(), e = ignoredTypeAttrs.end();
           i != e; ++i)
        diagnoseBadTypeAttribute(getSema(), **i, type);
    }

    ~TypeProcessingState() {
      if (trivial) return;

      restoreDeclSpecAttrs();
    }

  private:
    DeclSpec &getMutableDeclSpec() const {
      return const_cast<DeclSpec&>(declarator.getDeclSpec());
    }

    void restoreDeclSpecAttrs() {
      assert(hasSavedAttrs);

      if (savedAttrs.empty()) {
        getMutableDeclSpec().getAttributes().set(0);
        return;
      }

      getMutableDeclSpec().getAttributes().set(savedAttrs[0]);
      for (unsigned i = 0, e = savedAttrs.size() - 1; i != e; ++i)
        savedAttrs[i]->setNext(savedAttrs[i+1]);
      savedAttrs.back()->setNext(0);
    }
  };

  /// Basically std::pair except that we really want to avoid an
  /// implicit operator= for safety concerns.  It's also a minor
  /// link-time optimization for this to be a private type.
  struct AttrAndList {
    /// The attribute.
    AttributeList &first;

    /// The head of the list the attribute is currently in.
    AttributeList *&second;

    AttrAndList(AttributeList &attr, AttributeList *&head)
      : first(attr), second(head) {}
  };
}

namespace llvm {
  template <> struct isPodLike<AttrAndList> {
    static const bool value = true;
  };
}

static void spliceAttrIntoList(AttributeList &attr, AttributeList *&head) {
  attr.setNext(head);
  head = &attr;
}

static void spliceAttrOutOfList(AttributeList &attr, AttributeList *&head) {
  if (head == &attr) {
    head = attr.getNext();
    return;
  }

  AttributeList *cur = head;
  while (true) {
    assert(cur && cur->getNext() && "ran out of attrs?");
    if (cur->getNext() == &attr) {
      cur->setNext(attr.getNext());
      return;
    }
    cur = cur->getNext();
  }
}

static void moveAttrFromListToList(AttributeList &attr,
                                   AttributeList *&fromList,
                                   AttributeList *&toList) {
  spliceAttrOutOfList(attr, fromList);
  spliceAttrIntoList(attr, toList);
}

static void processTypeAttrs(TypeProcessingState &state,
                             QualType &type, bool isDeclSpec,
                             AttributeList *attrs);

static bool handleFunctionTypeAttr(TypeProcessingState &state,
                                   AttributeList &attr,
                                   QualType &type);

static bool handleObjCGCTypeAttr(TypeProcessingState &state,
                                 AttributeList &attr, QualType &type);

static bool handleObjCOwnershipTypeAttr(TypeProcessingState &state,
                                       AttributeList &attr, QualType &type);

static bool handleObjCPointerTypeAttr(TypeProcessingState &state,
                                      AttributeList &attr, QualType &type) {
  if (attr.getKind() == AttributeList::AT_ObjCGC)
    return handleObjCGCTypeAttr(state, attr, type);
  assert(attr.getKind() == AttributeList::AT_ObjCOwnership);
  return handleObjCOwnershipTypeAttr(state, attr, type);
}

/// Given that an objc_gc attribute was written somewhere on a
/// declaration *other* than on the declarator itself (for which, use
/// distributeObjCPointerTypeAttrFromDeclarator), and given that it
/// didn't apply in whatever position it was written in, try to move
/// it to a more appropriate position.
static void distributeObjCPointerTypeAttr(TypeProcessingState &state,
                                          AttributeList &attr,
                                          QualType type) {
  Declarator &declarator = state.getDeclarator();
  for (unsigned i = state.getCurrentChunkIndex(); i != 0; --i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i-1);
    switch (chunk.Kind) {
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
      moveAttrFromListToList(attr, state.getCurrentAttrListRef(),
                             chunk.getAttrListRef());
      return;

    case DeclaratorChunk::Paren:
    case DeclaratorChunk::Array:
      continue;

    // Don't walk through these.
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::Function:
    case DeclaratorChunk::MemberPointer:
      goto error;
    }
  }
 error:

  diagnoseBadTypeAttribute(state.getSema(), attr, type);
}

/// Distribute an objc_gc type attribute that was written on the
/// declarator.
static void
distributeObjCPointerTypeAttrFromDeclarator(TypeProcessingState &state,
                                            AttributeList &attr,
                                            QualType &declSpecType) {
  Declarator &declarator = state.getDeclarator();

  // objc_gc goes on the innermost pointer to something that's not a
  // pointer.
  unsigned innermost = -1U;
  bool considerDeclSpec = true;
  for (unsigned i = 0, e = declarator.getNumTypeObjects(); i != e; ++i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i);
    switch (chunk.Kind) {
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
      innermost = i;
      continue;

    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
    case DeclaratorChunk::Paren:
    case DeclaratorChunk::Array:
      continue;

    case DeclaratorChunk::Function:
      considerDeclSpec = false;
      goto done;
    }
  }
 done:

  // That might actually be the decl spec if we weren't blocked by
  // anything in the declarator.
  if (considerDeclSpec) {
    if (handleObjCPointerTypeAttr(state, attr, declSpecType)) {
      // Splice the attribute into the decl spec.  Prevents the
      // attribute from being applied multiple times and gives
      // the source-location-filler something to work with.
      state.saveDeclSpecAttrs();
      moveAttrFromListToList(attr, declarator.getAttrListRef(),
               declarator.getMutableDeclSpec().getAttributes().getListRef());
      return;
    }
  }

  // Otherwise, if we found an appropriate chunk, splice the attribute
  // into it.
  if (innermost != -1U) {
    moveAttrFromListToList(attr, declarator.getAttrListRef(),
                       declarator.getTypeObject(innermost).getAttrListRef());
    return;
  }

  // Otherwise, diagnose when we're done building the type.
  spliceAttrOutOfList(attr, declarator.getAttrListRef());
  state.addIgnoredTypeAttr(attr);
}

/// A function type attribute was written somewhere in a declaration
/// *other* than on the declarator itself or in the decl spec.  Given
/// that it didn't apply in whatever position it was written in, try
/// to move it to a more appropriate position.
static void distributeFunctionTypeAttr(TypeProcessingState &state,
                                       AttributeList &attr,
                                       QualType type) {
  Declarator &declarator = state.getDeclarator();

  // Try to push the attribute from the return type of a function to
  // the function itself.
  for (unsigned i = state.getCurrentChunkIndex(); i != 0; --i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i-1);
    switch (chunk.Kind) {
    case DeclaratorChunk::Function:
      moveAttrFromListToList(attr, state.getCurrentAttrListRef(),
                             chunk.getAttrListRef());
      return;

    case DeclaratorChunk::Paren:
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Array:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
      continue;
    }
  }

  diagnoseBadTypeAttribute(state.getSema(), attr, type);
}

/// Try to distribute a function type attribute to the innermost
/// function chunk or type.  Returns true if the attribute was
/// distributed, false if no location was found.
static bool
distributeFunctionTypeAttrToInnermost(TypeProcessingState &state,
                                      AttributeList &attr,
                                      AttributeList *&attrList,
                                      QualType &declSpecType) {
  Declarator &declarator = state.getDeclarator();

  // Put it on the innermost function chunk, if there is one.
  for (unsigned i = 0, e = declarator.getNumTypeObjects(); i != e; ++i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i);
    if (chunk.Kind != DeclaratorChunk::Function) continue;

    moveAttrFromListToList(attr, attrList, chunk.getAttrListRef());
    return true;
  }

  if (handleFunctionTypeAttr(state, attr, declSpecType)) {
    spliceAttrOutOfList(attr, attrList);
    return true;
  }

  return false;
}

/// A function type attribute was written in the decl spec.  Try to
/// apply it somewhere.
static void
distributeFunctionTypeAttrFromDeclSpec(TypeProcessingState &state,
                                       AttributeList &attr,
                                       QualType &declSpecType) {
  state.saveDeclSpecAttrs();

  // Try to distribute to the innermost.
  if (distributeFunctionTypeAttrToInnermost(state, attr,
                                            state.getCurrentAttrListRef(),
                                            declSpecType))
    return;

  // If that failed, diagnose the bad attribute when the declarator is
  // fully built.
  state.addIgnoredTypeAttr(attr);
}

/// A function type attribute was written on the declarator.  Try to
/// apply it somewhere.
static void
distributeFunctionTypeAttrFromDeclarator(TypeProcessingState &state,
                                         AttributeList &attr,
                                         QualType &declSpecType) {
  Declarator &declarator = state.getDeclarator();

  // Try to distribute to the innermost.
  if (distributeFunctionTypeAttrToInnermost(state, attr,
                                            declarator.getAttrListRef(),
                                            declSpecType))
    return;

  // If that failed, diagnose the bad attribute when the declarator is
  // fully built.
  spliceAttrOutOfList(attr, declarator.getAttrListRef());
  state.addIgnoredTypeAttr(attr);
}

/// \brief Given that there are attributes written on the declarator
/// itself, try to distribute any type attributes to the appropriate
/// declarator chunk.
///
/// These are attributes like the following:
///   int f ATTR;
///   int (f ATTR)();
/// but not necessarily this:
///   int f() ATTR;
static void distributeTypeAttrsFromDeclarator(TypeProcessingState &state,
                                              QualType &declSpecType) {
  // Collect all the type attributes from the declarator itself.
  assert(state.getDeclarator().getAttributes() && "declarator has no attrs!");
  AttributeList *attr = state.getDeclarator().getAttributes();
  AttributeList *next;
  do {
    next = attr->getNext();

    switch (attr->getKind()) {
    OBJC_POINTER_TYPE_ATTRS_CASELIST:
      distributeObjCPointerTypeAttrFromDeclarator(state, *attr, declSpecType);
      break;

    case AttributeList::AT_NSReturnsRetained:
      if (!state.getSema().getLangOpts().ObjCAutoRefCount)
        break;
      // fallthrough

    FUNCTION_TYPE_ATTRS_CASELIST:
      distributeFunctionTypeAttrFromDeclarator(state, *attr, declSpecType);
      break;

    default:
      break;
    }
  } while ((attr = next));
}

/// Add a synthetic '()' to a block-literal declarator if it is
/// required, given the return type.
static void maybeSynthesizeBlockSignature(TypeProcessingState &state,
                                          QualType declSpecType) {
  Declarator &declarator = state.getDeclarator();

  // First, check whether the declarator would produce a function,
  // i.e. whether the innermost semantic chunk is a function.
  if (declarator.isFunctionDeclarator()) {
    // If so, make that declarator a prototyped declarator.
    declarator.getFunctionTypeInfo().hasPrototype = true;
    return;
  }

  // If there are any type objects, the type as written won't name a
  // function, regardless of the decl spec type.  This is because a
  // block signature declarator is always an abstract-declarator, and
  // abstract-declarators can't just be parentheses chunks.  Therefore
  // we need to build a function chunk unless there are no type
  // objects and the decl spec type is a function.
  if (!declarator.getNumTypeObjects() && declSpecType->isFunctionType())
    return;

  // Note that there *are* cases with invalid declarators where
  // declarators consist solely of parentheses.  In general, these
  // occur only in failed efforts to make function declarators, so
  // faking up the function chunk is still the right thing to do.

  // Otherwise, we need to fake up a function declarator.
  SourceLocation loc = declarator.getLocStart();

  // ...and *prepend* it to the declarator.
  declarator.AddInnermostTypeInfo(DeclaratorChunk::getFunction(
                             /*proto*/ true,
                             /*variadic*/ false,
                             /*ambiguous*/ false, SourceLocation(),
                             /*args*/ 0, 0,
                             /*type quals*/ 0,
                             /*ref-qualifier*/true, SourceLocation(),
                             /*const qualifier*/SourceLocation(),
                             /*volatile qualifier*/SourceLocation(),
                             /*mutable qualifier*/SourceLocation(),
                             /*EH*/ EST_None, SourceLocation(), 0, 0, 0, 0,
                             /*parens*/ loc, loc,
                             declarator));

  // For consistency, make sure the state still has us as processing
  // the decl spec.
  assert(state.getCurrentChunkIndex() == declarator.getNumTypeObjects() - 1);
  state.setCurrentChunkIndex(declarator.getNumTypeObjects());
}

/// \brief Convert the specified declspec to the appropriate type
/// object.
/// \param state Specifies the declarator containing the declaration specifier
/// to be converted, along with other associated processing state.
/// \returns The type described by the declaration specifiers.  This function
/// never returns null.
static QualType ConvertDeclSpecToType(TypeProcessingState &state) {
  // FIXME: Should move the logic from DeclSpec::Finish to here for validity
  // checking.

  Sema &S = state.getSema();
  Declarator &declarator = state.getDeclarator();
  const DeclSpec &DS = declarator.getDeclSpec();
  SourceLocation DeclLoc = declarator.getIdentifierLoc();
  if (DeclLoc.isInvalid())
    DeclLoc = DS.getLocStart();

  ASTContext &Context = S.Context;

  QualType Result;
  switch (DS.getTypeSpecType()) {
  case DeclSpec::TST_void:
    Result = Context.VoidTy;
    break;
  case DeclSpec::TST_char:
    if (DS.getTypeSpecSign() == DeclSpec::TSS_unspecified)
      Result = Context.CharTy;
    else if (DS.getTypeSpecSign() == DeclSpec::TSS_signed)
      Result = Context.SignedCharTy;
    else {
      assert(DS.getTypeSpecSign() == DeclSpec::TSS_unsigned &&
             "Unknown TSS value");
      Result = Context.UnsignedCharTy;
    }
    break;
  case DeclSpec::TST_wchar:
    if (DS.getTypeSpecSign() == DeclSpec::TSS_unspecified)
      Result = Context.WCharTy;
    else if (DS.getTypeSpecSign() == DeclSpec::TSS_signed) {
      S.Diag(DS.getTypeSpecSignLoc(), diag::ext_invalid_sign_spec)
        << DS.getSpecifierName(DS.getTypeSpecType());
      Result = Context.getSignedWCharType();
    } else {
      assert(DS.getTypeSpecSign() == DeclSpec::TSS_unsigned &&
        "Unknown TSS value");
      S.Diag(DS.getTypeSpecSignLoc(), diag::ext_invalid_sign_spec)
        << DS.getSpecifierName(DS.getTypeSpecType());
      Result = Context.getUnsignedWCharType();
    }
    break;
  case DeclSpec::TST_char16:
      assert(DS.getTypeSpecSign() == DeclSpec::TSS_unspecified &&
        "Unknown TSS value");
      Result = Context.Char16Ty;
    break;
  case DeclSpec::TST_char32:
      assert(DS.getTypeSpecSign() == DeclSpec::TSS_unspecified &&
        "Unknown TSS value");
      Result = Context.Char32Ty;
    break;
  case DeclSpec::TST_unspecified:
    // "<proto1,proto2>" is an objc qualified ID with a missing id.
    if (DeclSpec::ProtocolQualifierListTy PQ = DS.getProtocolQualifiers()) {
      Result = Context.getObjCObjectType(Context.ObjCBuiltinIdTy,
                                         (ObjCProtocolDecl**)PQ,
                                         DS.getNumProtocolQualifiers());
      Result = Context.getObjCObjectPointerType(Result);
      break;
    }

    // If this is a missing declspec in a block literal return context, then it
    // is inferred from the return statements inside the block.
    // The declspec is always missing in a lambda expr context; it is either
    // specified with a trailing return type or inferred.
    if (declarator.getContext() == Declarator::LambdaExprContext ||
        isOmittedBlockReturnType(declarator)) {
      Result = Context.DependentTy;
      break;
    }

    // Unspecified typespec defaults to int in C90.  However, the C90 grammar
    // [C90 6.5] only allows a decl-spec if there was *some* type-specifier,
    // type-qualifier, or storage-class-specifier.  If not, emit an extwarn.
    // Note that the one exception to this is function definitions, which are
    // allowed to be completely missing a declspec.  This is handled in the
    // parser already though by it pretending to have seen an 'int' in this
    // case.
    if (S.getLangOpts().ImplicitInt) {
      // In C89 mode, we only warn if there is a completely missing declspec
      // when one is not allowed.
      if (DS.isEmpty()) {
        S.Diag(DeclLoc, diag::ext_missing_declspec)
          << DS.getSourceRange()
        << FixItHint::CreateInsertion(DS.getLocStart(), "int");
      }
    } else if (!DS.hasTypeSpecifier()) {
      // C99 and C++ require a type specifier.  For example, C99 6.7.2p2 says:
      // "At least one type specifier shall be given in the declaration
      // specifiers in each declaration, and in the specifier-qualifier list in
      // each struct declaration and type name."
      // FIXME: Does Microsoft really have the implicit int extension in C++?
      if (S.getLangOpts().CPlusPlus &&
          !S.getLangOpts().MicrosoftExt) {
        S.Diag(DeclLoc, diag::err_missing_type_specifier)
          << DS.getSourceRange();

        // When this occurs in C++ code, often something is very broken with the
        // value being declared, poison it as invalid so we don't get chains of
        // errors.
        declarator.setInvalidType(true);
      } else {
        S.Diag(DeclLoc, diag::ext_missing_type_specifier)
          << DS.getSourceRange();
      }
    }

    // FALL THROUGH.
  case DeclSpec::TST_int: {
    if (DS.getTypeSpecSign() != DeclSpec::TSS_unsigned) {
      switch (DS.getTypeSpecWidth()) {
      case DeclSpec::TSW_unspecified: Result = Context.IntTy; break;
      case DeclSpec::TSW_short:       Result = Context.ShortTy; break;
      case DeclSpec::TSW_long:        Result = Context.LongTy; break;
      case DeclSpec::TSW_longlong:
        Result = Context.LongLongTy;

        // long long is a C99 feature.
        if (!S.getLangOpts().C99)
          S.Diag(DS.getTypeSpecWidthLoc(),
                 S.getLangOpts().CPlusPlus0x ?
                   diag::warn_cxx98_compat_longlong : diag::ext_longlong);
        break;
      }
    } else {
      switch (DS.getTypeSpecWidth()) {
      case DeclSpec::TSW_unspecified: Result = Context.UnsignedIntTy; break;
      case DeclSpec::TSW_short:       Result = Context.UnsignedShortTy; break;
      case DeclSpec::TSW_long:        Result = Context.UnsignedLongTy; break;
      case DeclSpec::TSW_longlong:
        Result = Context.UnsignedLongLongTy;

        // long long is a C99 feature.
        if (!S.getLangOpts().C99)
          S.Diag(DS.getTypeSpecWidthLoc(),
                 S.getLangOpts().CPlusPlus0x ?
                   diag::warn_cxx98_compat_longlong : diag::ext_longlong);
        break;
      }
    }
    break;
  }
  case DeclSpec::TST_int128:
    if (DS.getTypeSpecSign() == DeclSpec::TSS_unsigned)
      Result = Context.UnsignedInt128Ty;
    else
      Result = Context.Int128Ty;
    break;
  case DeclSpec::TST_half: Result = Context.HalfTy; break;
  case DeclSpec::TST_float: Result = Context.FloatTy; break;
  case DeclSpec::TST_double:
    if (DS.getTypeSpecWidth() == DeclSpec::TSW_long)
      Result = Context.LongDoubleTy;
    else
      Result = Context.DoubleTy;

    if (S.getLangOpts().OpenCL && !S.getOpenCLOptions().cl_khr_fp64) {
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_double_requires_fp64);
      declarator.setInvalidType(true);
    }
    break;
  case DeclSpec::TST_bool: Result = Context.BoolTy; break; // _Bool or bool
  case DeclSpec::TST_decimal32:    // _Decimal32
  case DeclSpec::TST_decimal64:    // _Decimal64
  case DeclSpec::TST_decimal128:   // _Decimal128
    S.Diag(DS.getTypeSpecTypeLoc(), diag::err_decimal_unsupported);
    Result = Context.IntTy;
    declarator.setInvalidType(true);
    break;
  case DeclSpec::TST_class:
  case DeclSpec::TST_enum:
  case DeclSpec::TST_union:
  case DeclSpec::TST_struct: {
    TypeDecl *D = dyn_cast_or_null<TypeDecl>(DS.getRepAsDecl());
    if (!D) {
      // This can happen in C++ with ambiguous lookups.
      Result = Context.IntTy;
      declarator.setInvalidType(true);
      break;
    }

    // If the type is deprecated or unavailable, diagnose it.
    S.DiagnoseUseOfDecl(D, DS.getTypeSpecTypeNameLoc());

    assert(DS.getTypeSpecWidth() == 0 && DS.getTypeSpecComplex() == 0 &&
           DS.getTypeSpecSign() == 0 && "No qualifiers on tag names!");

    // TypeQuals handled by caller.
    Result = Context.getTypeDeclType(D);

    // In both C and C++, make an ElaboratedType.
    ElaboratedTypeKeyword Keyword
      = ElaboratedType::getKeywordForTypeSpec(DS.getTypeSpecType());
    Result = S.getElaboratedType(Keyword, DS.getTypeSpecScope(), Result);
    break;
  }
  case DeclSpec::TST_typename: {
    assert(DS.getTypeSpecWidth() == 0 && DS.getTypeSpecComplex() == 0 &&
           DS.getTypeSpecSign() == 0 &&
           "Can't handle qualifiers on typedef names yet!");
    Result = S.GetTypeFromParser(DS.getRepAsType());
    if (Result.isNull())
      declarator.setInvalidType(true);
    else if (DeclSpec::ProtocolQualifierListTy PQ
               = DS.getProtocolQualifiers()) {
      if (const ObjCObjectType *ObjT = Result->getAs<ObjCObjectType>()) {
        // Silently drop any existing protocol qualifiers.
        // TODO: determine whether that's the right thing to do.
        if (ObjT->getNumProtocols())
          Result = ObjT->getBaseType();

        if (DS.getNumProtocolQualifiers())
          Result = Context.getObjCObjectType(Result,
                                             (ObjCProtocolDecl**) PQ,
                                             DS.getNumProtocolQualifiers());
      } else if (Result->isObjCIdType()) {
        // id<protocol-list>
        Result = Context.getObjCObjectType(Context.ObjCBuiltinIdTy,
                                           (ObjCProtocolDecl**) PQ,
                                           DS.getNumProtocolQualifiers());
        Result = Context.getObjCObjectPointerType(Result);
      } else if (Result->isObjCClassType()) {
        // Class<protocol-list>
        Result = Context.getObjCObjectType(Context.ObjCBuiltinClassTy,
                                           (ObjCProtocolDecl**) PQ,
                                           DS.getNumProtocolQualifiers());
        Result = Context.getObjCObjectPointerType(Result);
      } else {
        S.Diag(DeclLoc, diag::err_invalid_protocol_qualifiers)
          << DS.getSourceRange();
        declarator.setInvalidType(true);
      }
    }

    // TypeQuals handled by caller.
    break;
  }
  case DeclSpec::TST_typeofType:
    // FIXME: Preserve type source info.
    Result = S.GetTypeFromParser(DS.getRepAsType());
    assert(!Result.isNull() && "Didn't get a type for typeof?");
    if (!Result->isDependentType())
      if (const TagType *TT = Result->getAs<TagType>())
        S.DiagnoseUseOfDecl(TT->getDecl(), DS.getTypeSpecTypeLoc());
    // TypeQuals handled by caller.
    Result = Context.getTypeOfType(Result);
    break;
  case DeclSpec::TST_typeofExpr: {
    Expr *E = DS.getRepAsExpr();
    assert(E && "Didn't get an expression for typeof?");
    // TypeQuals handled by caller.
    Result = S.BuildTypeofExprType(E, DS.getTypeSpecTypeLoc());
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;
  }
  case DeclSpec::TST_decltype: {
    Expr *E = DS.getRepAsExpr();
    assert(E && "Didn't get an expression for decltype?");
    // TypeQuals handled by caller.
    Result = S.BuildDecltypeType(E, DS.getTypeSpecTypeLoc());
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;
  }
  case DeclSpec::TST_underlyingType:
    Result = S.GetTypeFromParser(DS.getRepAsType());
    assert(!Result.isNull() && "Didn't get a type for __underlying_type?");
    Result = S.BuildUnaryTransformType(Result,
                                       UnaryTransformType::EnumUnderlyingType,
                                       DS.getTypeSpecTypeLoc());
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;

  case DeclSpec::TST_auto: {
    // TypeQuals handled by caller.
    Result = Context.getAutoType(QualType());
    break;
  }

  case DeclSpec::TST_unknown_anytype:
    Result = Context.UnknownAnyTy;
    break;

  case DeclSpec::TST_atomic:
    Result = S.GetTypeFromParser(DS.getRepAsType());
    assert(!Result.isNull() && "Didn't get a type for _Atomic?");
    Result = S.BuildAtomicType(Result, DS.getTypeSpecTypeLoc());
    if (Result.isNull()) {
      Result = Context.IntTy;
      declarator.setInvalidType(true);
    }
    break;

  case DeclSpec::TST_error:
    Result = Context.IntTy;
    declarator.setInvalidType(true);
    break;
  }

  // Handle complex types.
  if (DS.getTypeSpecComplex() == DeclSpec::TSC_complex) {
    if (S.getLangOpts().Freestanding)
      S.Diag(DS.getTypeSpecComplexLoc(), diag::ext_freestanding_complex);
    Result = Context.getComplexType(Result);
  } else if (DS.isTypeAltiVecVector()) {
    unsigned typeSize = static_cast<unsigned>(Context.getTypeSize(Result));
    assert(typeSize > 0 && "type size for vector must be greater than 0 bits");
    VectorType::VectorKind VecKind = VectorType::AltiVecVector;
    if (DS.isTypeAltiVecPixel())
      VecKind = VectorType::AltiVecPixel;
    else if (DS.isTypeAltiVecBool())
      VecKind = VectorType::AltiVecBool;
    Result = Context.getVectorType(Result, 128/typeSize, VecKind);
  }

  // FIXME: Imaginary.
  if (DS.getTypeSpecComplex() == DeclSpec::TSC_imaginary)
    S.Diag(DS.getTypeSpecComplexLoc(), diag::err_imaginary_not_supported);

  // Before we process any type attributes, synthesize a block literal
  // function declarator if necessary.
  if (declarator.getContext() == Declarator::BlockLiteralContext)
    maybeSynthesizeBlockSignature(state, Result);

  // Apply any type attributes from the decl spec.  This may cause the
  // list of type attributes to be temporarily saved while the type
  // attributes are pushed around.
  if (AttributeList *attrs = DS.getAttributes().getList())
    processTypeAttrs(state, Result, true, attrs);

  // Apply const/volatile/restrict qualifiers to T.
  if (unsigned TypeQuals = DS.getTypeQualifiers()) {

    // Enforce C99 6.7.3p2: "Types other than pointer types derived from object
    // or incomplete types shall not be restrict-qualified."  C++ also allows
    // restrict-qualified references.
    if (TypeQuals & DeclSpec::TQ_restrict) {
      if (Result->isAnyPointerType() || Result->isReferenceType()) {
        QualType EltTy;
        if (Result->isObjCObjectPointerType())
          EltTy = Result;
        else
          EltTy = Result->isPointerType() ?
                    Result->getAs<PointerType>()->getPointeeType() :
                    Result->getAs<ReferenceType>()->getPointeeType();

        // If we have a pointer or reference, the pointee must have an object
        // incomplete type.
        if (!EltTy->isIncompleteOrObjectType()) {
          S.Diag(DS.getRestrictSpecLoc(),
               diag::err_typecheck_invalid_restrict_invalid_pointee)
            << EltTy << DS.getSourceRange();
          TypeQuals &= ~DeclSpec::TQ_restrict; // Remove the restrict qualifier.
        }
      } else {
        S.Diag(DS.getRestrictSpecLoc(),
               diag::err_typecheck_invalid_restrict_not_pointer)
          << Result << DS.getSourceRange();
        TypeQuals &= ~DeclSpec::TQ_restrict; // Remove the restrict qualifier.
      }
    }

    // Warn about CV qualifiers on functions: C99 6.7.3p8: "If the specification
    // of a function type includes any type qualifiers, the behavior is
    // undefined."
    if (Result->isFunctionType() && TypeQuals) {
      // Get some location to point at, either the C or V location.
      SourceLocation Loc;
      if (TypeQuals & DeclSpec::TQ_const)
        Loc = DS.getConstSpecLoc();
      else if (TypeQuals & DeclSpec::TQ_volatile)
        Loc = DS.getVolatileSpecLoc();
      else {
        assert((TypeQuals & DeclSpec::TQ_restrict) &&
               "Has CVR quals but not C, V, or R?");
        Loc = DS.getRestrictSpecLoc();
      }
      S.Diag(Loc, diag::warn_typecheck_function_qualifiers)
        << Result << DS.getSourceRange();
    }

    // C++ [dcl.ref]p1:
    //   Cv-qualified references are ill-formed except when the
    //   cv-qualifiers are introduced through the use of a typedef
    //   (7.1.3) or of a template type argument (14.3), in which
    //   case the cv-qualifiers are ignored.
    // FIXME: Shouldn't we be checking SCS_typedef here?
    if (DS.getTypeSpecType() == DeclSpec::TST_typename &&
        TypeQuals && Result->isReferenceType()) {
      TypeQuals &= ~DeclSpec::TQ_const;
      TypeQuals &= ~DeclSpec::TQ_volatile;
    }

    // C90 6.5.3 constraints: "The same type qualifier shall not appear more
    // than once in the same specifier-list or qualifier-list, either directly
    // or via one or more typedefs."
    if (!S.getLangOpts().C99 && !S.getLangOpts().CPlusPlus
        && TypeQuals & Result.getCVRQualifiers()) {
      if (TypeQuals & DeclSpec::TQ_const && Result.isConstQualified()) {
        S.Diag(DS.getConstSpecLoc(), diag::ext_duplicate_declspec)
          << "const";
      }

      if (TypeQuals & DeclSpec::TQ_volatile && Result.isVolatileQualified()) {
        S.Diag(DS.getVolatileSpecLoc(), diag::ext_duplicate_declspec)
          << "volatile";
      }

      // C90 doesn't have restrict, so it doesn't force us to produce a warning
      // in this case.
    }

    Qualifiers Quals = Qualifiers::fromCVRMask(TypeQuals);
    Result = Context.getQualifiedType(Result, Quals);
  }

  return Result;
}

static std::string getPrintableNameForEntity(DeclarationName Entity) {
  if (Entity)
    return Entity.getAsString();

  return "type name";
}

QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
                                  Qualifiers Qs) {
  // Enforce C99 6.7.3p2: "Types other than pointer types derived from
  // object or incomplete types shall not be restrict-qualified."
  if (Qs.hasRestrict()) {
    unsigned DiagID = 0;
    QualType ProblemTy;

    const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
    if (const ReferenceType *RTy = dyn_cast<ReferenceType>(Ty)) {
      if (!RTy->getPointeeType()->isIncompleteOrObjectType()) {
        DiagID = diag::err_typecheck_invalid_restrict_invalid_pointee;
        ProblemTy = T->getAs<ReferenceType>()->getPointeeType();
      }
    } else if (const PointerType *PTy = dyn_cast<PointerType>(Ty)) {
      if (!PTy->getPointeeType()->isIncompleteOrObjectType()) {
        DiagID = diag::err_typecheck_invalid_restrict_invalid_pointee;
        ProblemTy = T->getAs<PointerType>()->getPointeeType();
      }
    } else if (const MemberPointerType *PTy = dyn_cast<MemberPointerType>(Ty)) {
      if (!PTy->getPointeeType()->isIncompleteOrObjectType()) {
        DiagID = diag::err_typecheck_invalid_restrict_invalid_pointee;
        ProblemTy = T->getAs<PointerType>()->getPointeeType();
      }
    } else if (!Ty->isDependentType()) {
      // FIXME: this deserves a proper diagnostic
      DiagID = diag::err_typecheck_invalid_restrict_invalid_pointee;
      ProblemTy = T;
    }

    if (DiagID) {
      Diag(Loc, DiagID) << ProblemTy;
      Qs.removeRestrict();
    }
  }

  return Context.getQualifiedType(T, Qs);
}

/// \brief Build a paren type including \p T.
QualType Sema::BuildParenType(QualType T) {
  return Context.getParenType(T);
}

/// Given that we're building a pointer or reference to the given
static QualType inferARCLifetimeForPointee(Sema &S, QualType type,
                                           SourceLocation loc,
                                           bool isReference) {
  // Bail out if retention is unrequired or already specified.
  if (!type->isObjCLifetimeType() ||
      type.getObjCLifetime() != Qualifiers::OCL_None)
    return type;

  Qualifiers::ObjCLifetime implicitLifetime = Qualifiers::OCL_None;

  // If the object type is const-qualified, we can safely use
  // __unsafe_unretained.  This is safe (because there are no read
  // barriers), and it'll be safe to coerce anything but __weak* to
  // the resulting type.
  if (type.isConstQualified()) {
    implicitLifetime = Qualifiers::OCL_ExplicitNone;

  // Otherwise, check whether the static type does not require
  // retaining.  This currently only triggers for Class (possibly
  // protocol-qualifed, and arrays thereof).
  } else if (type->isObjCARCImplicitlyUnretainedType()) {
    implicitLifetime = Qualifiers::OCL_ExplicitNone;

  // If we are in an unevaluated context, like sizeof, skip adding a
  // qualification.
  } else if (S.isUnevaluatedContext()) {
    return type;

  // If that failed, give an error and recover using __strong.  __strong
  // is the option most likely to prevent spurious second-order diagnostics,
  // like when binding a reference to a field.
  } else {
    // These types can show up in private ivars in system headers, so
    // we need this to not be an error in those cases.  Instead we
    // want to delay.
    if (S.DelayedDiagnostics.shouldDelayDiagnostics()) {
      S.DelayedDiagnostics.add(
          sema::DelayedDiagnostic::makeForbiddenType(loc,
              diag::err_arc_indirect_no_ownership, type, isReference));
    } else {
      S.Diag(loc, diag::err_arc_indirect_no_ownership) << type << isReference;
    }
    implicitLifetime = Qualifiers::OCL_Strong;
  }
  assert(implicitLifetime && "didn't infer any lifetime!");

  Qualifiers qs;
  qs.addObjCLifetime(implicitLifetime);
  return S.Context.getQualifiedType(type, qs);
}

/// \brief Build a pointer type.
///
/// \param T The type to which we'll be building a pointer.
///
/// \param Loc The location of the entity whose type involves this
/// pointer type or, if there is no such entity, the location of the
/// type that will have pointer type.
///
/// \param Entity The name of the entity that involves the pointer
/// type, if known.
///
/// \returns A suitable pointer type, if there are no
/// errors. Otherwise, returns a NULL type.
QualType Sema::BuildPointerType(QualType T,
                                SourceLocation Loc, DeclarationName Entity) {
  if (T->isReferenceType()) {
    // C++ 8.3.2p4: There shall be no ... pointers to references ...
    Diag(Loc, diag::err_illegal_decl_pointer_to_reference)
      << getPrintableNameForEntity(Entity) << T;
    return QualType();
  }

  assert(!T->isObjCObjectType() && "Should build ObjCObjectPointerType");

  // In ARC, it is forbidden to build pointers to unqualified pointers.
  if (getLangOpts().ObjCAutoRefCount)
    T = inferARCLifetimeForPointee(*this, T, Loc, /*reference*/ false);

  // Build the pointer type.
  return Context.getPointerType(T);
}

/// \brief Build a reference type.
///
/// \param T The type to which we'll be building a reference.
///
/// \param Loc The location of the entity whose type involves this
/// reference type or, if there is no such entity, the location of the
/// type that will have reference type.
///
/// \param Entity The name of the entity that involves the reference
/// type, if known.
///
/// \returns A suitable reference type, if there are no
/// errors. Otherwise, returns a NULL type.
QualType Sema::BuildReferenceType(QualType T, bool SpelledAsLValue,
                                  SourceLocation Loc,
                                  DeclarationName Entity) {
  assert(Context.getCanonicalType(T) != Context.OverloadTy &&
         "Unresolved overloaded function type");

  // C++0x [dcl.ref]p6:
  //   If a typedef (7.1.3), a type template-parameter (14.3.1), or a
  //   decltype-specifier (7.1.6.2) denotes a type TR that is a reference to a
  //   type T, an attempt to create the type "lvalue reference to cv TR" creates
  //   the type "lvalue reference to T", while an attempt to create the type
  //   "rvalue reference to cv TR" creates the type TR.
  bool LValueRef = SpelledAsLValue || T->getAs<LValueReferenceType>();

  // C++ [dcl.ref]p4: There shall be no references to references.
  //
  // According to C++ DR 106, references to references are only
  // diagnosed when they are written directly (e.g., "int & &"),
  // but not when they happen via a typedef:
  //
  //   typedef int& intref;
  //   typedef intref& intref2;
  //
  // Parser::ParseDeclaratorInternal diagnoses the case where
  // references are written directly; here, we handle the
  // collapsing of references-to-references as described in C++0x.
  // DR 106 and 540 introduce reference-collapsing into C++98/03.

  // C++ [dcl.ref]p1:
  //   A declarator that specifies the type "reference to cv void"
  //   is ill-formed.
  if (T->isVoidType()) {
    Diag(Loc, diag::err_reference_to_void);
    return QualType();
  }

  // In ARC, it is forbidden to build references to unqualified pointers.
  if (getLangOpts().ObjCAutoRefCount)
    T = inferARCLifetimeForPointee(*this, T, Loc, /*reference*/ true);

  // Handle restrict on references.
  if (LValueRef)
    return Context.getLValueReferenceType(T, SpelledAsLValue);
  return Context.getRValueReferenceType(T);
}

/// Check whether the specified array size makes the array type a VLA.  If so,
/// return true, if not, return the size of the array in SizeVal.
static bool isArraySizeVLA(Sema &S, Expr *ArraySize, llvm::APSInt &SizeVal) {
  // If the size is an ICE, it certainly isn't a VLA. If we're in a GNU mode
  // (like gnu99, but not c99) accept any evaluatable value as an extension.
  class VLADiagnoser : public Sema::VerifyICEDiagnoser {
  public:
    VLADiagnoser() : Sema::VerifyICEDiagnoser(true) {}

    virtual void diagnoseNotICE(Sema &S, SourceLocation Loc, SourceRange SR) {
    }

    virtual void diagnoseFold(Sema &S, SourceLocation Loc, SourceRange SR) {
      S.Diag(Loc, diag::ext_vla_folded_to_constant) << SR;
    }
  } Diagnoser;

  return S.VerifyIntegerConstantExpression(ArraySize, &SizeVal, Diagnoser,
                                           S.LangOpts.GNUMode).isInvalid();
}


/// \brief Build an array type.
///
/// \param T The type of each element in the array.
///
/// \param ASM C99 array size modifier (e.g., '*', 'static').
///
/// \param ArraySize Expression describing the size of the array.
///
/// \param Brackets The range from the opening '[' to the closing ']'.
///
/// \param Entity The name of the entity that involves the array
/// type, if known.
///
/// \returns A suitable array type, if there are no errors. Otherwise,
/// returns a NULL type.
QualType Sema::BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
                              Expr *ArraySize, unsigned Quals,
                              SourceRange Brackets, DeclarationName Entity) {

  SourceLocation Loc = Brackets.getBegin();
  if (getLangOpts().CPlusPlus) {
    // C++ [dcl.array]p1:
    //   T is called the array element type; this type shall not be a reference
    //   type, the (possibly cv-qualified) type void, a function type or an
    //   abstract class type.
    //
    // C++ [dcl.array]p3:
    //   When several "array of" specifications are adjacent, [...] only the
    //   first of the constant expressions that specify the bounds of the arrays
    //   may be omitted.
    //
    // Note: function types are handled in the common path with C.
    if (T->isReferenceType()) {
      Diag(Loc, diag::err_illegal_decl_array_of_references)
      << getPrintableNameForEntity(Entity) << T;
      return QualType();
    }

    if (T->isVoidType() || T->isIncompleteArrayType()) {
      Diag(Loc, diag::err_illegal_decl_array_incomplete_type) << T;
      return QualType();
    }

    if (RequireNonAbstractType(Brackets.getBegin(), T,
                               diag::err_array_of_abstract_type))
      return QualType();

  } else {
    // C99 6.7.5.2p1: If the element type is an incomplete or function type,
    // reject it (e.g. void ary[7], struct foo ary[7], void ary[7]())
    if (RequireCompleteType(Loc, T,
                            diag::err_illegal_decl_array_incomplete_type))
      return QualType();
  }

  if (T->isFunctionType()) {
    Diag(Loc, diag::err_illegal_decl_array_of_functions)
      << getPrintableNameForEntity(Entity) << T;
    return QualType();
  }

  if (T->getContainedAutoType()) {
    Diag(Loc, diag::err_illegal_decl_array_of_auto)
      << getPrintableNameForEntity(Entity) << T;
    return QualType();
  }

  if (const RecordType *EltTy = T->getAs<RecordType>()) {
    // If the element type is a struct or union that contains a variadic
    // array, accept it as a GNU extension: C99 6.7.2.1p2.
    if (EltTy->getDecl()->hasFlexibleArrayMember())
      Diag(Loc, diag::ext_flexible_array_in_array) << T;
  } else if (T->isObjCObjectType()) {
    Diag(Loc, diag::err_objc_array_of_interfaces) << T;
    return QualType();
  }

  // Do placeholder conversions on the array size expression.
  if (ArraySize && ArraySize->hasPlaceholderType()) {
    ExprResult Result = CheckPlaceholderExpr(ArraySize);
    if (Result.isInvalid()) return QualType();
    ArraySize = Result.take();
  }

  // Do lvalue-to-rvalue conversions on the array size expression.
  if (ArraySize && !ArraySize->isRValue()) {
    ExprResult Result = DefaultLvalueConversion(ArraySize);
    if (Result.isInvalid())
      return QualType();

    ArraySize = Result.take();
  }

  // C99 6.7.5.2p1: The size expression shall have integer type.
  // C++11 allows contextual conversions to such types.
  if (!getLangOpts().CPlusPlus0x &&
      ArraySize && !ArraySize->isTypeDependent() &&
      !ArraySize->getType()->isIntegralOrUnscopedEnumerationType()) {
    Diag(ArraySize->getLocStart(), diag::err_array_size_non_int)
      << ArraySize->getType() << ArraySize->getSourceRange();
    return QualType();
  }

  llvm::APSInt ConstVal(Context.getTypeSize(Context.getSizeType()));
  if (!ArraySize) {
    if (ASM == ArrayType::Star)
      T = Context.getVariableArrayType(T, 0, ASM, Quals, Brackets);
    else
      T = Context.getIncompleteArrayType(T, ASM, Quals);
  } else if (ArraySize->isTypeDependent() || ArraySize->isValueDependent()) {
    T = Context.getDependentSizedArrayType(T, ArraySize, ASM, Quals, Brackets);
  } else if ((!T->isDependentType() && !T->isIncompleteType() &&
              !T->isConstantSizeType()) ||
             isArraySizeVLA(*this, ArraySize, ConstVal)) {
    // Even in C++11, don't allow contextual conversions in the array bound
    // of a VLA.
    if (getLangOpts().CPlusPlus0x &&
        !ArraySize->getType()->isIntegralOrUnscopedEnumerationType()) {
      Diag(ArraySize->getLocStart(), diag::err_array_size_non_int)
        << ArraySize->getType() << ArraySize->getSourceRange();
      return QualType();
    }

    // C99: an array with an element type that has a non-constant-size is a VLA.
    // C99: an array with a non-ICE size is a VLA.  We accept any expression
    // that we can fold to a non-zero positive value as an extension.
    T = Context.getVariableArrayType(T, ArraySize, ASM, Quals, Brackets);
  } else {
    // C99 6.7.5.2p1: If the expression is a constant expression, it shall
    // have a value greater than zero.
    if (ConstVal.isSigned() && ConstVal.isNegative()) {
      if (Entity)
        Diag(ArraySize->getLocStart(), diag::err_decl_negative_array_size)
          << getPrintableNameForEntity(Entity) << ArraySize->getSourceRange();
      else
        Diag(ArraySize->getLocStart(), diag::err_typecheck_negative_array_size)
          << ArraySize->getSourceRange();
      return QualType();
    }
    if (ConstVal == 0) {
      // GCC accepts zero sized static arrays. We allow them when
      // we're not in a SFINAE context.
      Diag(ArraySize->getLocStart(),
           isSFINAEContext()? diag::err_typecheck_zero_array_size
                            : diag::ext_typecheck_zero_array_size)
        << ArraySize->getSourceRange();

      if (ASM == ArrayType::Static) {
        Diag(ArraySize->getLocStart(),
             diag::warn_typecheck_zero_static_array_size)
          << ArraySize->getSourceRange();
        ASM = ArrayType::Normal;
      }
    } else if (!T->isDependentType() && !T->isVariablyModifiedType() &&
               !T->isIncompleteType()) {
      // Is the array too large?
      unsigned ActiveSizeBits
        = ConstantArrayType::getNumAddressingBits(Context, T, ConstVal);
      if (ActiveSizeBits > ConstantArrayType::getMaxSizeBits(Context))
        Diag(ArraySize->getLocStart(), diag::err_array_too_large)
          << ConstVal.toString(10)
          << ArraySize->getSourceRange();
    }

    T = Context.getConstantArrayType(T, ConstVal, ASM, Quals);
  }
  // If this is not C99, extwarn about VLA's and C99 array size modifiers.
  if (!getLangOpts().C99) {
    if (T->isVariableArrayType()) {
      // Prohibit the use of non-POD types in VLAs.
      QualType BaseT = Context.getBaseElementType(T);
      if (!T->isDependentType() &&
          !BaseT.isPODType(Context) &&
          !BaseT->isObjCLifetimeType()) {
        Diag(Loc, diag::err_vla_non_pod)
          << BaseT;
        return QualType();
      }
      // Prohibit the use of VLAs during template argument deduction.
      else if (isSFINAEContext()) {
        Diag(Loc, diag::err_vla_in_sfinae);
        return QualType();
      }
      // Just extwarn about VLAs.
      else
        Diag(Loc, diag::ext_vla);
    } else if (ASM != ArrayType::Normal || Quals != 0)
      Diag(Loc,
           getLangOpts().CPlusPlus? diag::err_c99_array_usage_cxx
                                     : diag::ext_c99_array_usage) << ASM;
  }

  return T;
}

/// \brief Build an ext-vector type.
///
/// Run the required checks for the extended vector type.
QualType Sema::BuildExtVectorType(QualType T, Expr *ArraySize,
                                  SourceLocation AttrLoc) {
  // unlike gcc's vector_size attribute, we do not allow vectors to be defined
  // in conjunction with complex types (pointers, arrays, functions, etc.).
  if (!T->isDependentType() &&
      !T->isIntegerType() && !T->isRealFloatingType()) {
    Diag(AttrLoc, diag::err_attribute_invalid_vector_type) << T;
    return QualType();
  }

  if (!ArraySize->isTypeDependent() && !ArraySize->isValueDependent()) {
    llvm::APSInt vecSize(32);
    if (!ArraySize->isIntegerConstantExpr(vecSize, Context)) {
      Diag(AttrLoc, diag::err_attribute_argument_not_int)
        << "ext_vector_type" << ArraySize->getSourceRange();
      return QualType();
    }

    // unlike gcc's vector_size attribute, the size is specified as the
    // number of elements, not the number of bytes.
    unsigned vectorSize = static_cast<unsigned>(vecSize.getZExtValue());

    if (vectorSize == 0) {
      Diag(AttrLoc, diag::err_attribute_zero_size)
      << ArraySize->getSourceRange();
      return QualType();
    }

    return Context.getExtVectorType(T, vectorSize);
  }

  return Context.getDependentSizedExtVectorType(T, ArraySize, AttrLoc);
}

/// \brief Build a function type.
///
/// This routine checks the function type according to C++ rules and
/// under the assumption that the result type and parameter types have
/// just been instantiated from a template. It therefore duplicates
/// some of the behavior of GetTypeForDeclarator, but in a much
/// simpler form that is only suitable for this narrow use case.
///
/// \param T The return type of the function.
///
/// \param ParamTypes The parameter types of the function. This array
/// will be modified to account for adjustments to the types of the
/// function parameters.
///
/// \param NumParamTypes The number of parameter types in ParamTypes.
///
/// \param Variadic Whether this is a variadic function type.
///
/// \param HasTrailingReturn Whether this function has a trailing return type.
///
/// \param Quals The cvr-qualifiers to be applied to the function type.
///
/// \param Loc The location of the entity whose type involves this
/// function type or, if there is no such entity, the location of the
/// type that will have function type.
///
/// \param Entity The name of the entity that involves the function
/// type, if known.
///
/// \returns A suitable function type, if there are no
/// errors. Otherwise, returns a NULL type.
QualType Sema::BuildFunctionType(QualType T,
                                 QualType *ParamTypes,
                                 unsigned NumParamTypes,
                                 bool Variadic, bool HasTrailingReturn,
                                 unsigned Quals,
                                 RefQualifierKind RefQualifier,
                                 SourceLocation Loc, DeclarationName Entity,
                                 FunctionType::ExtInfo Info) {
  if (T->isArrayType() || T->isFunctionType()) {
    Diag(Loc, diag::err_func_returning_array_function)
      << T->isFunctionType() << T;
    return QualType();
  }

  // Functions cannot return half FP.
  if (T->isHalfType()) {
    Diag(Loc, diag::err_parameters_retval_cannot_have_fp16_type) << 1 <<
      FixItHint::CreateInsertion(Loc, "*");
    return QualType();
  }

  bool Invalid = false;
  for (unsigned Idx = 0; Idx < NumParamTypes; ++Idx) {
    // FIXME: Loc is too inprecise here, should use proper locations for args.
    QualType ParamType = Context.getAdjustedParameterType(ParamTypes[Idx]);
    if (ParamType->isVoidType()) {
      Diag(Loc, diag::err_param_with_void_type);
      Invalid = true;
    } else if (ParamType->isHalfType()) {
      // Disallow half FP arguments.
      Diag(Loc, diag::err_parameters_retval_cannot_have_fp16_type) << 0 <<
        FixItHint::CreateInsertion(Loc, "*");
      Invalid = true;
    }

    ParamTypes[Idx] = ParamType;
  }

  if (Invalid)
    return QualType();

  FunctionProtoType::ExtProtoInfo EPI;
  EPI.Variadic = Variadic;
  EPI.HasTrailingReturn = HasTrailingReturn;
  EPI.TypeQuals = Quals;
  EPI.RefQualifier = RefQualifier;
  EPI.ExtInfo = Info;

  return Context.getFunctionType(T, ParamTypes, NumParamTypes, EPI);
}

/// \brief Build a member pointer type \c T Class::*.
///
/// \param T the type to which the member pointer refers.
/// \param Class the class type into which the member pointer points.
/// \param Loc the location where this type begins
/// \param Entity the name of the entity that will have this member pointer type
///
/// \returns a member pointer type, if successful, or a NULL type if there was
/// an error.
QualType Sema::BuildMemberPointerType(QualType T, QualType Class,
                                      SourceLocation Loc,
                                      DeclarationName Entity) {
  // Verify that we're not building a pointer to pointer to function with
  // exception specification.
  if (CheckDistantExceptionSpec(T)) {
    Diag(Loc, diag::err_distant_exception_spec);

    // FIXME: If we're doing this as part of template instantiation,
    // we should return immediately.

    // Build the type anyway, but use the canonical type so that the
    // exception specifiers are stripped off.
    T = Context.getCanonicalType(T);
  }

  // C++ 8.3.3p3: A pointer to member shall not point to ... a member
  //   with reference type, or "cv void."
  if (T->isReferenceType()) {
    Diag(Loc, diag::err_illegal_decl_mempointer_to_reference)
      << (Entity? Entity.getAsString() : "type name") << T;
    return QualType();
  }

  if (T->isVoidType()) {
    Diag(Loc, diag::err_illegal_decl_mempointer_to_void)
      << (Entity? Entity.getAsString() : "type name");
    return QualType();
  }

  if (!Class->isDependentType() && !Class->isRecordType()) {
    Diag(Loc, diag::err_mempointer_in_nonclass_type) << Class;
    return QualType();
  }

  // In the Microsoft ABI, the class is allowed to be an incomplete
  // type. In such cases, the compiler makes a worst-case assumption.
  // We make no such assumption right now, so emit an error if the
  // class isn't a complete type.
  if (Context.getTargetInfo().getCXXABI() == CXXABI_Microsoft &&
      RequireCompleteType(Loc, Class, diag::err_incomplete_type))
    return QualType();

  return Context.getMemberPointerType(T, Class.getTypePtr());
}

/// \brief Build a block pointer type.
///
/// \param T The type to which we'll be building a block pointer.
///
/// \param Loc The source location, used for diagnostics.
///
/// \param Entity The name of the entity that involves the block pointer
/// type, if known.
///
/// \returns A suitable block pointer type, if there are no
/// errors. Otherwise, returns a NULL type.
QualType Sema::BuildBlockPointerType(QualType T,
                                     SourceLocation Loc,
                                     DeclarationName Entity) {
  if (!T->isFunctionType()) {
    Diag(Loc, diag::err_nonfunction_block_type);
    return QualType();
  }

  return Context.getBlockPointerType(T);
}

QualType Sema::GetTypeFromParser(ParsedType Ty, TypeSourceInfo **TInfo) {
  QualType QT = Ty.get();
  if (QT.isNull()) {
    if (TInfo) *TInfo = 0;
    return QualType();
  }

  TypeSourceInfo *DI = 0;
  if (const LocInfoType *LIT = dyn_cast<LocInfoType>(QT)) {
    QT = LIT->getType();
    DI = LIT->getTypeSourceInfo();
  }

  if (TInfo) *TInfo = DI;
  return QT;
}

static void transferARCOwnershipToDeclaratorChunk(TypeProcessingState &state,
                                            Qualifiers::ObjCLifetime ownership,
                                            unsigned chunkIndex);

/// Given that this is the declaration of a parameter under ARC,
/// attempt to infer attributes and such for pointer-to-whatever
/// types.
static void inferARCWriteback(TypeProcessingState &state,
                              QualType &declSpecType) {
  Sema &S = state.getSema();
  Declarator &declarator = state.getDeclarator();

  // TODO: should we care about decl qualifiers?

  // Check whether the declarator has the expected form.  We walk
  // from the inside out in order to make the block logic work.
  unsigned outermostPointerIndex = 0;
  bool isBlockPointer = false;
  unsigned numPointers = 0;
  for (unsigned i = 0, e = declarator.getNumTypeObjects(); i != e; ++i) {
    unsigned chunkIndex = i;
    DeclaratorChunk &chunk = declarator.getTypeObject(chunkIndex);
    switch (chunk.Kind) {
    case DeclaratorChunk::Paren:
      // Ignore parens.
      break;

    case DeclaratorChunk::Reference:
    case DeclaratorChunk::Pointer:
      // Count the number of pointers.  Treat references
      // interchangeably as pointers; if they're mis-ordered, normal
      // type building will discover that.
      outermostPointerIndex = chunkIndex;
      numPointers++;
      break;

    case DeclaratorChunk::BlockPointer:
      // If we have a pointer to block pointer, that's an acceptable
      // indirect reference; anything else is not an application of
      // the rules.
      if (numPointers != 1) return;
      numPointers++;
      outermostPointerIndex = chunkIndex;
      isBlockPointer = true;

      // We don't care about pointer structure in return values here.
      goto done;

    case DeclaratorChunk::Array: // suppress if written (id[])?
    case DeclaratorChunk::Function:
    case DeclaratorChunk::MemberPointer:
      return;
    }
  }
 done:

  // If we have *one* pointer, then we want to throw the qualifier on
  // the declaration-specifiers, which means that it needs to be a
  // retainable object type.
  if (numPointers == 1) {
    // If it's not a retainable object type, the rule doesn't apply.
    if (!declSpecType->isObjCRetainableType()) return;

    // If it already has lifetime, don't do anything.
    if (declSpecType.getObjCLifetime()) return;

    // Otherwise, modify the type in-place.
    Qualifiers qs;

    if (declSpecType->isObjCARCImplicitlyUnretainedType())
      qs.addObjCLifetime(Qualifiers::OCL_ExplicitNone);
    else
      qs.addObjCLifetime(Qualifiers::OCL_Autoreleasing);
    declSpecType = S.Context.getQualifiedType(declSpecType, qs);

  // If we have *two* pointers, then we want to throw the qualifier on
  // the outermost pointer.
  } else if (numPointers == 2) {
    // If we don't have a block pointer, we need to check whether the
    // declaration-specifiers gave us something that will turn into a
    // retainable object pointer after we slap the first pointer on it.
    if (!isBlockPointer && !declSpecType->isObjCObjectType())
      return;

    // Look for an explicit lifetime attribute there.
    DeclaratorChunk &chunk = declarator.getTypeObject(outermostPointerIndex);
    if (chunk.Kind != DeclaratorChunk::Pointer &&
        chunk.Kind != DeclaratorChunk::BlockPointer)
      return;
    for (const AttributeList *attr = chunk.getAttrs(); attr;
           attr = attr->getNext())
      if (attr->getKind() == AttributeList::AT_ObjCOwnership)
        return;

    transferARCOwnershipToDeclaratorChunk(state, Qualifiers::OCL_Autoreleasing,
                                          outermostPointerIndex);

  // Any other number of pointers/references does not trigger the rule.
  } else return;

  // TODO: mark whether we did this inference?
}

static void DiagnoseIgnoredQualifiers(unsigned Quals,
                                      SourceLocation ConstQualLoc,
                                      SourceLocation VolatileQualLoc,
                                      SourceLocation RestrictQualLoc,
                                      Sema& S) {
  std::string QualStr;
  unsigned NumQuals = 0;
  SourceLocation Loc;

  FixItHint ConstFixIt;
  FixItHint VolatileFixIt;
  FixItHint RestrictFixIt;

  const SourceManager &SM = S.getSourceManager();

  // FIXME: The locations here are set kind of arbitrarily. It'd be nicer to
  // find a range and grow it to encompass all the qualifiers, regardless of
  // the order in which they textually appear.
  if (Quals & Qualifiers::Const) {
    ConstFixIt = FixItHint::CreateRemoval(ConstQualLoc);
    QualStr = "const";
    ++NumQuals;
    if (!Loc.isValid() || SM.isBeforeInTranslationUnit(ConstQualLoc, Loc))
      Loc = ConstQualLoc;
  }
  if (Quals & Qualifiers::Volatile) {
    VolatileFixIt = FixItHint::CreateRemoval(VolatileQualLoc);
    QualStr += (NumQuals == 0 ? "volatile" : " volatile");
    ++NumQuals;
    if (!Loc.isValid() || SM.isBeforeInTranslationUnit(VolatileQualLoc, Loc))
      Loc = VolatileQualLoc;
  }
  if (Quals & Qualifiers::Restrict) {
    RestrictFixIt = FixItHint::CreateRemoval(RestrictQualLoc);
    QualStr += (NumQuals == 0 ? "restrict" : " restrict");
    ++NumQuals;
    if (!Loc.isValid() || SM.isBeforeInTranslationUnit(RestrictQualLoc, Loc))
      Loc = RestrictQualLoc;
  }

  assert(NumQuals > 0 && "No known qualifiers?");

  S.Diag(Loc, diag::warn_qual_return_type)
    << QualStr << NumQuals << ConstFixIt << VolatileFixIt << RestrictFixIt;
}

static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
                                             TypeSourceInfo *&ReturnTypeInfo) {
  Sema &SemaRef = state.getSema();
  Declarator &D = state.getDeclarator();
  QualType T;
  ReturnTypeInfo = 0;

  // The TagDecl owned by the DeclSpec.
  TagDecl *OwnedTagDecl = 0;

  switch (D.getName().getKind()) {
  case UnqualifiedId::IK_ImplicitSelfParam:
  case UnqualifiedId::IK_OperatorFunctionId:
  case UnqualifiedId::IK_Identifier:
  case UnqualifiedId::IK_LiteralOperatorId:
  case UnqualifiedId::IK_TemplateId:
    T = ConvertDeclSpecToType(state);

    if (!D.isInvalidType() && D.getDeclSpec().isTypeSpecOwned()) {
      OwnedTagDecl = cast<TagDecl>(D.getDeclSpec().getRepAsDecl());
      // Owned declaration is embedded in declarator.
      OwnedTagDecl->setEmbeddedInDeclarator(true);
    }
    break;

  case UnqualifiedId::IK_ConstructorName:
  case UnqualifiedId::IK_ConstructorTemplateId:
  case UnqualifiedId::IK_DestructorName:
    // Constructors and destructors don't have return types. Use
    // "void" instead.
    T = SemaRef.Context.VoidTy;
    if (AttributeList *attrs = D.getDeclSpec().getAttributes().getList())
      processTypeAttrs(state, T, true, attrs);
    break;

  case UnqualifiedId::IK_ConversionFunctionId:
    // The result type of a conversion function is the type that it
    // converts to.
    T = SemaRef.GetTypeFromParser(D.getName().ConversionFunctionId,
                                  &ReturnTypeInfo);
    break;
  }

  if (D.getAttributes())
    distributeTypeAttrsFromDeclarator(state, T);

  // C++11 [dcl.spec.auto]p5: reject 'auto' if it is not in an allowed context.
  // In C++11, a function declarator using 'auto' must have a trailing return
  // type (this is checked later) and we can skip this. In other languages
  // using auto, we need to check regardless.
  if (D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_auto &&
      (!SemaRef.getLangOpts().CPlusPlus0x || !D.isFunctionDeclarator())) {
    int Error = -1;

    switch (D.getContext()) {
    case Declarator::KNRTypeListContext:
      llvm_unreachable("K&R type lists aren't allowed in C++");
    case Declarator::LambdaExprContext:
      llvm_unreachable("Can't specify a type specifier in lambda grammar");
    case Declarator::ObjCParameterContext:
    case Declarator::ObjCResultContext:
    case Declarator::PrototypeContext:
      Error = 0; // Function prototype
      break;
    case Declarator::MemberContext:
      if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_static)
        break;
      switch (cast<TagDecl>(SemaRef.CurContext)->getTagKind()) {
      case TTK_Enum: llvm_unreachable("unhandled tag kind");
      case TTK_Struct: Error = 1; /* Struct member */ break;
      case TTK_Union:  Error = 2; /* Union member */ break;
      case TTK_Class:  Error = 3; /* Class member */ break;
      }
      break;
    case Declarator::CXXCatchContext:
    case Declarator::ObjCCatchContext:
      Error = 4; // Exception declaration
      break;
    case Declarator::TemplateParamContext:
      Error = 5; // Template parameter
      break;
    case Declarator::BlockLiteralContext:
      Error = 6; // Block literal
      break;
    case Declarator::TemplateTypeArgContext:
      Error = 7; // Template type argument
      break;
    case Declarator::AliasDeclContext:
    case Declarator::AliasTemplateContext:
      Error = 9; // Type alias
      break;
    case Declarator::TrailingReturnContext:
      Error = 10; // Function return type
      break;
    case Declarator::TypeNameContext:
      Error = 11; // Generic
      break;
    case Declarator::FileContext:
    case Declarator::BlockContext:
    case Declarator::ForContext:
    case Declarator::ConditionContext:
    case Declarator::CXXNewContext:
      break;
    }

    if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef)
      Error = 8;

    // In Objective-C it is an error to use 'auto' on a function declarator.
    if (D.isFunctionDeclarator())
      Error = 10;

    // C++11 [dcl.spec.auto]p2: 'auto' is always fine if the declarator
    // contains a trailing return type. That is only legal at the outermost
    // level. Check all declarator chunks (outermost first) anyway, to give
    // better diagnostics.
    if (SemaRef.getLangOpts().CPlusPlus0x && Error != -1) {
      for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
        unsigned chunkIndex = e - i - 1;
        state.setCurrentChunkIndex(chunkIndex);
        DeclaratorChunk &DeclType = D.getTypeObject(chunkIndex);
        if (DeclType.Kind == DeclaratorChunk::Function) {
          const DeclaratorChunk::FunctionTypeInfo &FTI = DeclType.Fun;
          if (FTI.hasTrailingReturnType()) {
            Error = -1;
            break;
          }
        }
      }
    }

    if (Error != -1) {
      SemaRef.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
                   diag::err_auto_not_allowed)
        << Error;
      T = SemaRef.Context.IntTy;
      D.setInvalidType(true);
    } else
      SemaRef.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
                   diag::warn_cxx98_compat_auto_type_specifier);
  }

  if (SemaRef.getLangOpts().CPlusPlus &&
      OwnedTagDecl && OwnedTagDecl->isCompleteDefinition()) {
    // Check the contexts where C++ forbids the declaration of a new class
    // or enumeration in a type-specifier-seq.
    switch (D.getContext()) {
    case Declarator::TrailingReturnContext:
      // Class and enumeration definitions are syntactically not allowed in
      // trailing return types.
      llvm_unreachable("parser should not have allowed this");
      break;
    case Declarator::FileContext:
    case Declarator::MemberContext:
    case Declarator::BlockContext:
    case Declarator::ForContext:
    case Declarator::BlockLiteralContext:
    case Declarator::LambdaExprContext:
      // C++11 [dcl.type]p3:
      //   A type-specifier-seq shall not define a class or enumeration unless
      //   it appears in the type-id of an alias-declaration (7.1.3) that is not
      //   the declaration of a template-declaration.
    case Declarator::AliasDeclContext:
      break;
    case Declarator::AliasTemplateContext:
      SemaRef.Diag(OwnedTagDecl->getLocation(),
             diag::err_type_defined_in_alias_template)
        << SemaRef.Context.getTypeDeclType(OwnedTagDecl);
      break;
    case Declarator::TypeNameContext:
    case Declarator::TemplateParamContext:
    case Declarator::CXXNewContext:
    case Declarator::CXXCatchContext:
    case Declarator::ObjCCatchContext:
    case Declarator::TemplateTypeArgContext:
      SemaRef.Diag(OwnedTagDecl->getLocation(),
             diag::err_type_defined_in_type_specifier)
        << SemaRef.Context.getTypeDeclType(OwnedTagDecl);
      break;
    case Declarator::PrototypeContext:
    case Declarator::ObjCParameterContext:
    case Declarator::ObjCResultContext:
    case Declarator::KNRTypeListContext:
      // C++ [dcl.fct]p6:
      //   Types shall not be defined in return or parameter types.
      SemaRef.Diag(OwnedTagDecl->getLocation(),
                   diag::err_type_defined_in_param_type)
        << SemaRef.Context.getTypeDeclType(OwnedTagDecl);
      break;
    case Declarator::ConditionContext:
      // C++ 6.4p2:
      // The type-specifier-seq shall not contain typedef and shall not declare
      // a new class or enumeration.
      SemaRef.Diag(OwnedTagDecl->getLocation(),
                   diag::err_type_defined_in_condition);
      break;
    }
  }

  return T;
}

static std::string getFunctionQualifiersAsString(const FunctionProtoType *FnTy){
  std::string Quals =
    Qualifiers::fromCVRMask(FnTy->getTypeQuals()).getAsString();

  switch (FnTy->getRefQualifier()) {
  case RQ_None:
    break;

  case RQ_LValue:
    if (!Quals.empty())
      Quals += ' ';
    Quals += '&';
    break;

  case RQ_RValue:
    if (!Quals.empty())
      Quals += ' ';
    Quals += "&&";
    break;
  }

  return Quals;
}

/// Check that the function type T, which has a cv-qualifier or a ref-qualifier,
/// can be contained within the declarator chunk DeclType, and produce an
/// appropriate diagnostic if not.
static void checkQualifiedFunction(Sema &S, QualType T,
                                   DeclaratorChunk &DeclType) {
  // C++98 [dcl.fct]p4 / C++11 [dcl.fct]p6: a function type with a
  // cv-qualifier or a ref-qualifier can only appear at the topmost level
  // of a type.
  int DiagKind = -1;
  switch (DeclType.Kind) {
  case DeclaratorChunk::Paren:
  case DeclaratorChunk::MemberPointer:
    // These cases are permitted.
    return;
  case DeclaratorChunk::Array:
  case DeclaratorChunk::Function:
    // These cases don't allow function types at all; no need to diagnose the
    // qualifiers separately.
    return;
  case DeclaratorChunk::BlockPointer:
    DiagKind = 0;
    break;
  case DeclaratorChunk::Pointer:
    DiagKind = 1;
    break;
  case DeclaratorChunk::Reference:
    DiagKind = 2;
    break;
  }

  assert(DiagKind != -1);
  S.Diag(DeclType.Loc, diag::err_compound_qualified_function_type)
    << DiagKind << isa<FunctionType>(T.IgnoreParens()) << T
    << getFunctionQualifiersAsString(T->castAs<FunctionProtoType>());
}

/// Produce an approprioate diagnostic for an ambiguity between a function
/// declarator and a C++ direct-initializer.
static void warnAboutAmbiguousFunction(Sema &S, Declarator &D,
                                       DeclaratorChunk &DeclType, QualType RT) {
  const DeclaratorChunk::FunctionTypeInfo &FTI = DeclType.Fun;
  assert(FTI.isAmbiguous && "no direct-initializer / function ambiguity");

  // If the return type is void there is no ambiguity.
  if (RT->isVoidType())
    return;

  // An initializer for a non-class type can have at most one argument.
  if (!RT->isRecordType() && FTI.NumArgs > 1)
    return;

  // An initializer for a reference must have exactly one argument.
  if (RT->isReferenceType() && FTI.NumArgs != 1)
    return;

  // Only warn if this declarator is declaring a function at block scope, and
  // doesn't have a storage class (such as 'extern') specified.
  if (!D.isFunctionDeclarator() ||
      D.getFunctionDefinitionKind() != FDK_Declaration ||
      !S.CurContext->isFunctionOrMethod() ||
      D.getDeclSpec().getStorageClassSpecAsWritten()
        != DeclSpec::SCS_unspecified)
    return;

  // Inside a condition, a direct initializer is not permitted. We allow one to
  // be parsed in order to give better diagnostics in condition parsing.
  if (D.getContext() == Declarator::ConditionContext)
    return;

  SourceRange ParenRange(DeclType.Loc, DeclType.EndLoc);

  S.Diag(DeclType.Loc,
         FTI.NumArgs ? diag::warn_parens_disambiguated_as_function_declaration
                     : diag::warn_empty_parens_are_function_decl)
    << ParenRange;

  // If the declaration looks like:
  //   T var1,
  //   f();
  // and name lookup finds a function named 'f', then the ',' was
  // probably intended to be a ';'.
  if (!D.isFirstDeclarator() && D.getIdentifier()) {
    FullSourceLoc Comma(D.getCommaLoc(), S.SourceMgr);
    FullSourceLoc Name(D.getIdentifierLoc(), S.SourceMgr);
    if (Comma.getFileID() != Name.getFileID() ||
        Comma.getSpellingLineNumber() != Name.getSpellingLineNumber()) {
      LookupResult Result(S, D.getIdentifier(), SourceLocation(),
                          Sema::LookupOrdinaryName);
      if (S.LookupName(Result, S.getCurScope()))
        S.Diag(D.getCommaLoc(), diag::note_empty_parens_function_call)
          << FixItHint::CreateReplacement(D.getCommaLoc(), ";")
          << D.getIdentifier();
    }
  }

  if (FTI.NumArgs > 0) {
    // For a declaration with parameters, eg. "T var(T());", suggest adding parens
    // around the first parameter to turn the declaration into a variable
    // declaration.
    SourceRange Range = FTI.ArgInfo[0].Param->getSourceRange();
    SourceLocation B = Range.getBegin();
    SourceLocation E = S.PP.getLocForEndOfToken(Range.getEnd());
    // FIXME: Maybe we should suggest adding braces instead of parens
    // in C++11 for classes that don't have an initializer_list constructor.
    S.Diag(B, diag::note_additional_parens_for_variable_declaration)
      << FixItHint::CreateInsertion(B, "(")
      << FixItHint::CreateInsertion(E, ")");
  } else {
    // For a declaration without parameters, eg. "T var();", suggest replacing the
    // parens with an initializer to turn the declaration into a variable
    // declaration.
    const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();

    // Empty parens mean value-initialization, and no parens mean
    // default initialization. These are equivalent if the default
    // constructor is user-provided or if zero-initialization is a
    // no-op.
    if (RD && RD->hasDefinition() &&
        (RD->isEmpty() || RD->hasUserProvidedDefaultConstructor()))
      S.Diag(DeclType.Loc, diag::note_empty_parens_default_ctor)
        << FixItHint::CreateRemoval(ParenRange);
    else {
      std::string Init = S.getFixItZeroInitializerForType(RT);
      if (Init.empty() && S.LangOpts.CPlusPlus0x)
        Init = "{}";
      if (!Init.empty())
        S.Diag(DeclType.Loc, diag::note_empty_parens_zero_initialize)
          << FixItHint::CreateReplacement(ParenRange, Init);
    }
  }
}

static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
                                                QualType declSpecType,
                                                TypeSourceInfo *TInfo) {

  QualType T = declSpecType;
  Declarator &D = state.getDeclarator();
  Sema &S = state.getSema();
  ASTContext &Context = S.Context;
  const LangOptions &LangOpts = S.getLangOpts();

  bool ImplicitlyNoexcept = false;
  if (D.getName().getKind() == UnqualifiedId::IK_OperatorFunctionId &&
      LangOpts.CPlusPlus0x) {
    OverloadedOperatorKind OO = D.getName().OperatorFunctionId.Operator;
    /// In C++0x, deallocation functions (normal and array operator delete)
    /// are implicitly noexcept.
    if (OO == OO_Delete || OO == OO_Array_Delete)
      ImplicitlyNoexcept = true;
  }

  // The name we're declaring, if any.
  DeclarationName Name;
  if (D.getIdentifier())
    Name = D.getIdentifier();

  // Does this declaration declare a typedef-name?
  bool IsTypedefName =
    D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef ||
    D.getContext() == Declarator::AliasDeclContext ||
    D.getContext() == Declarator::AliasTemplateContext;

  // Does T refer to a function type with a cv-qualifier or a ref-qualifier?
  bool IsQualifiedFunction = T->isFunctionProtoType() &&
      (T->castAs<FunctionProtoType>()->getTypeQuals() != 0 ||
       T->castAs<FunctionProtoType>()->getRefQualifier() != RQ_None);

  // Walk the DeclTypeInfo, building the recursive type as we go.
  // DeclTypeInfos are ordered from the identifier out, which is
  // opposite of what we want :).
  for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
    unsigned chunkIndex = e - i - 1;
    state.setCurrentChunkIndex(chunkIndex);
    DeclaratorChunk &DeclType = D.getTypeObject(chunkIndex);
    if (IsQualifiedFunction) {
      checkQualifiedFunction(S, T, DeclType);
      IsQualifiedFunction = DeclType.Kind == DeclaratorChunk::Paren;
    }
    switch (DeclType.Kind) {
    case DeclaratorChunk::Paren:
      T = S.BuildParenType(T);
      break;
    case DeclaratorChunk::BlockPointer:
      // If blocks are disabled, emit an error.
      if (!LangOpts.Blocks)
        S.Diag(DeclType.Loc, diag::err_blocks_disable);

      T = S.BuildBlockPointerType(T, D.getIdentifierLoc(), Name);
      if (DeclType.Cls.TypeQuals)
        T = S.BuildQualifiedType(T, DeclType.Loc, DeclType.Cls.TypeQuals);
      break;
    case DeclaratorChunk::Pointer:
      // Verify that we're not building a pointer to pointer to function with
      // exception specification.
      if (LangOpts.CPlusPlus && S.CheckDistantExceptionSpec(T)) {
        S.Diag(D.getIdentifierLoc(), diag::err_distant_exception_spec);
        D.setInvalidType(true);
        // Build the type anyway.
      }
      if (LangOpts.ObjC1 && T->getAs<ObjCObjectType>()) {
        T = Context.getObjCObjectPointerType(T);
        if (DeclType.Ptr.TypeQuals)
          T = S.BuildQualifiedType(T, DeclType.Loc, DeclType.Ptr.TypeQuals);
        break;
      }
      T = S.BuildPointerType(T, DeclType.Loc, Name);
      if (DeclType.Ptr.TypeQuals)
        T = S.BuildQualifiedType(T, DeclType.Loc, DeclType.Ptr.TypeQuals);

      break;
    case DeclaratorChunk::Reference: {
      // Verify that we're not building a reference to pointer to function with
      // exception specification.
      if (LangOpts.CPlusPlus && S.CheckDistantExceptionSpec(T)) {
        S.Diag(D.getIdentifierLoc(), diag::err_distant_exception_spec);
        D.setInvalidType(true);
        // Build the type anyway.
      }
      T = S.BuildReferenceType(T, DeclType.Ref.LValueRef, DeclType.Loc, Name);

      Qualifiers Quals;
      if (DeclType.Ref.HasRestrict)
        T = S.BuildQualifiedType(T, DeclType.Loc, Qualifiers::Restrict);
      break;
    }
    case DeclaratorChunk::Array: {
      // Verify that we're not building an array of pointers to function with
      // exception specification.
      if (LangOpts.CPlusPlus && S.CheckDistantExceptionSpec(T)) {
        S.Diag(D.getIdentifierLoc(), diag::err_distant_exception_spec);
        D.setInvalidType(true);
        // Build the type anyway.
      }
      DeclaratorChunk::ArrayTypeInfo &ATI = DeclType.Arr;
      Expr *ArraySize = static_cast<Expr*>(ATI.NumElts);
      ArrayType::ArraySizeModifier ASM;
      if (ATI.isStar)
        ASM = ArrayType::Star;
      else if (ATI.hasStatic)
        ASM = ArrayType::Static;
      else
        ASM = ArrayType::Normal;
      if (ASM == ArrayType::Star && !D.isPrototypeContext()) {
        // FIXME: This check isn't quite right: it allows star in prototypes
        // for function definitions, and disallows some edge cases detailed
        // in http://gcc.gnu.org/ml/gcc-patches/2009-02/msg00133.html
        S.Diag(DeclType.Loc, diag::err_array_star_outside_prototype);
        ASM = ArrayType::Normal;
        D.setInvalidType(true);
      }

      // C99 6.7.5.2p1: The optional type qualifiers and the keyword static
      // shall appear only in a declaration of a function parameter with an
      // array type, ...
      if (ASM == ArrayType::Static || ATI.TypeQuals) {
        if (!(D.isPrototypeContext() ||
              D.getContext() == Declarator::KNRTypeListContext)) {
          S.Diag(DeclType.Loc, diag::err_array_static_outside_prototype) <<
              (ASM == ArrayType::Static ? "'static'" : "type qualifier");
          // Remove the 'static' and the type qualifiers.
          if (ASM == ArrayType::Static)
            ASM = ArrayType::Normal;
          ATI.TypeQuals = 0;
          D.setInvalidType(true);
        }

        // C99 6.7.5.2p1: ... and then only in the outermost array type
        // derivation.
        unsigned x = chunkIndex;
        while (x != 0) {
          // Walk outwards along the declarator chunks.
          x--;
          const DeclaratorChunk &DC = D.getTypeObject(x);
          switch (DC.Kind) {
          case DeclaratorChunk::Paren:
            continue;
          case DeclaratorChunk::Array:
          case DeclaratorChunk::Pointer:
          case DeclaratorChunk::Reference:
          case DeclaratorChunk::MemberPointer:
            S.Diag(DeclType.Loc, diag::err_array_static_not_outermost) <<
              (ASM == ArrayType::Static ? "'static'" : "type qualifier");
            if (ASM == ArrayType::Static)
              ASM = ArrayType::Normal;
            ATI.TypeQuals = 0;
            D.setInvalidType(true);
            break;
          case DeclaratorChunk::Function:
          case DeclaratorChunk::BlockPointer:
            // These are invalid anyway, so just ignore.
            break;
          }
        }
      }

      T = S.BuildArrayType(T, ASM, ArraySize, ATI.TypeQuals,
                           SourceRange(DeclType.Loc, DeclType.EndLoc), Name);
      break;
    }
    case DeclaratorChunk::Function: {
      // If the function declarator has a prototype (i.e. it is not () and
      // does not have a K&R-style identifier list), then the arguments are part
      // of the type, otherwise the argument list is ().
      const DeclaratorChunk::FunctionTypeInfo &FTI = DeclType.Fun;
      IsQualifiedFunction = FTI.TypeQuals || FTI.hasRefQualifier();

      // Check for auto functions and trailing return type and adjust the
      // return type accordingly.
      if (!D.isInvalidType()) {
        // trailing-return-type is only required if we're declaring a function,
        // and not, for instance, a pointer to a function.
        if (D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_auto &&
            !FTI.hasTrailingReturnType() && chunkIndex == 0) {
          S.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
               diag::err_auto_missing_trailing_return);
          T = Context.IntTy;
          D.setInvalidType(true);
        } else if (FTI.hasTrailingReturnType()) {
          // T must be exactly 'auto' at this point. See CWG issue 681.
          if (isa<ParenType>(T)) {
            S.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
                 diag::err_trailing_return_in_parens)
              << T << D.getDeclSpec().getSourceRange();
            D.setInvalidType(true);
          } else if (D.getContext() != Declarator::LambdaExprContext &&
                     (T.hasQualifiers() || !isa<AutoType>(T))) {
            S.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
                 diag::err_trailing_return_without_auto)
              << T << D.getDeclSpec().getSourceRange();
            D.setInvalidType(true);
          }
          T = S.GetTypeFromParser(FTI.getTrailingReturnType(), &TInfo);
          if (T.isNull()) {
            // An error occurred parsing the trailing return type.
            T = Context.IntTy;
            D.setInvalidType(true);
          }
        }
      }

      // C99 6.7.5.3p1: The return type may not be a function or array type.
      // For conversion functions, we'll diagnose this particular error later.
      if ((T->isArrayType() || T->isFunctionType()) &&
          (D.getName().getKind() != UnqualifiedId::IK_ConversionFunctionId)) {
        unsigned diagID = diag::err_func_returning_array_function;
        // Last processing chunk in block context means this function chunk
        // represents the block.
        if (chunkIndex == 0 &&
            D.getContext() == Declarator::BlockLiteralContext)
          diagID = diag::err_block_returning_array_function;
        S.Diag(DeclType.Loc, diagID) << T->isFunctionType() << T;
        T = Context.IntTy;
        D.setInvalidType(true);
      }

      // Do not allow returning half FP value.
      // FIXME: This really should be in BuildFunctionType.
      if (T->isHalfType()) {
        S.Diag(D.getIdentifierLoc(),
             diag::err_parameters_retval_cannot_have_fp16_type) << 1
          << FixItHint::CreateInsertion(D.getIdentifierLoc(), "*");
        D.setInvalidType(true);
      }

      // cv-qualifiers on return types are pointless except when the type is a
      // class type in C++.
      if (isa<PointerType>(T) && T.getLocalCVRQualifiers() &&
          (D.getName().getKind() != UnqualifiedId::IK_ConversionFunctionId) &&
          (!LangOpts.CPlusPlus || !T->isDependentType())) {
        assert(chunkIndex + 1 < e && "No DeclaratorChunk for the return type?");
        DeclaratorChunk ReturnTypeChunk = D.getTypeObject(chunkIndex + 1);
        assert(ReturnTypeChunk.Kind == DeclaratorChunk::Pointer);

        DeclaratorChunk::PointerTypeInfo &PTI = ReturnTypeChunk.Ptr;

        DiagnoseIgnoredQualifiers(PTI.TypeQuals,
            SourceLocation::getFromRawEncoding(PTI.ConstQualLoc),
            SourceLocation::getFromRawEncoding(PTI.VolatileQualLoc),
            SourceLocation::getFromRawEncoding(PTI.RestrictQualLoc),
            S);

      } else if (T.getCVRQualifiers() && D.getDeclSpec().getTypeQualifiers() &&
          (!LangOpts.CPlusPlus ||
           (!T->isDependentType() && !T->isRecordType()))) {

        DiagnoseIgnoredQualifiers(D.getDeclSpec().getTypeQualifiers(),
                                  D.getDeclSpec().getConstSpecLoc(),
                                  D.getDeclSpec().getVolatileSpecLoc(),
                                  D.getDeclSpec().getRestrictSpecLoc(),
                                  S);
      }

      if (LangOpts.CPlusPlus && D.getDeclSpec().isTypeSpecOwned()) {
        // C++ [dcl.fct]p6:
        //   Types shall not be defined in return or parameter types.
        TagDecl *Tag = cast<TagDecl>(D.getDeclSpec().getRepAsDecl());
        if (Tag->isCompleteDefinition())
          S.Diag(Tag->getLocation(), diag::err_type_defined_in_result_type)
            << Context.getTypeDeclType(Tag);
      }

      // Exception specs are not allowed in typedefs. Complain, but add it
      // anyway.
      if (IsTypedefName && FTI.getExceptionSpecType())
        S.Diag(FTI.getExceptionSpecLoc(), diag::err_exception_spec_in_typedef)
          << (D.getContext() == Declarator::AliasDeclContext ||
              D.getContext() == Declarator::AliasTemplateContext);

      // If we see "T var();" or "T var(T());" at block scope, it is probably
      // an attempt to initialize a variable, not a function declaration.
      if (FTI.isAmbiguous)
        warnAboutAmbiguousFunction(S, D, DeclType, T);

      if (!FTI.NumArgs && !FTI.isVariadic && !LangOpts.CPlusPlus) {
        // Simple void foo(), where the incoming T is the result type.
        T = Context.getFunctionNoProtoType(T);
      } else {
        // We allow a zero-parameter variadic function in C if the
        // function is marked with the "overloadable" attribute. Scan
        // for this attribute now.
        if (!FTI.NumArgs && FTI.isVariadic && !LangOpts.CPlusPlus) {
          bool Overloadable = false;
          for (const AttributeList *Attrs = D.getAttributes();
               Attrs; Attrs = Attrs->getNext()) {
            if (Attrs->getKind() == AttributeList::AT_Overloadable) {
              Overloadable = true;
              break;
            }
          }

          if (!Overloadable)
            S.Diag(FTI.getEllipsisLoc(), diag::err_ellipsis_first_arg);
        }

        if (FTI.NumArgs && FTI.ArgInfo[0].Param == 0) {
          // C99 6.7.5.3p3: Reject int(x,y,z) when it's not a function
          // definition.
          S.Diag(FTI.ArgInfo[0].IdentLoc, diag::err_ident_list_in_fn_declaration);
          D.setInvalidType(true);
          break;
        }

        FunctionProtoType::ExtProtoInfo EPI;
        EPI.Variadic = FTI.isVariadic;
        EPI.HasTrailingReturn = FTI.hasTrailingReturnType();
        EPI.TypeQuals = FTI.TypeQuals;
        EPI.RefQualifier = !FTI.hasRefQualifier()? RQ_None
                    : FTI.RefQualifierIsLValueRef? RQ_LValue
                    : RQ_RValue;

        // Otherwise, we have a function with an argument list that is
        // potentially variadic.
        SmallVector<QualType, 16> ArgTys;
        ArgTys.reserve(FTI.NumArgs);

        SmallVector<bool, 16> ConsumedArguments;
        ConsumedArguments.reserve(FTI.NumArgs);
        bool HasAnyConsumedArguments = false;

        for (unsigned i = 0, e = FTI.NumArgs; i != e; ++i) {
          ParmVarDecl *Param = cast<ParmVarDecl>(FTI.ArgInfo[i].Param);
          QualType ArgTy = Param->getType();
          assert(!ArgTy.isNull() && "Couldn't parse type?");

          // Adjust the parameter type.
          assert((ArgTy == Context.getAdjustedParameterType(ArgTy)) &&
                 "Unadjusted type?");

          // Look for 'void'.  void is allowed only as a single argument to a
          // function with no other parameters (C99 6.7.5.3p10).  We record
          // int(void) as a FunctionProtoType with an empty argument list.
          if (ArgTy->isVoidType()) {
            // If this is something like 'float(int, void)', reject it.  'void'
            // is an incomplete type (C99 6.2.5p19) and function decls cannot
            // have arguments of incomplete type.
            if (FTI.NumArgs != 1 || FTI.isVariadic) {
              S.Diag(DeclType.Loc, diag::err_void_only_param);
              ArgTy = Context.IntTy;
              Param->setType(ArgTy);
            } else if (FTI.ArgInfo[i].Ident) {
              // Reject, but continue to parse 'int(void abc)'.
              S.Diag(FTI.ArgInfo[i].IdentLoc,
                   diag::err_param_with_void_type);
              ArgTy = Context.IntTy;
              Param->setType(ArgTy);
            } else {
              // Reject, but continue to parse 'float(const void)'.
              if (ArgTy.hasQualifiers())
                S.Diag(DeclType.Loc, diag::err_void_param_qualified);

              // Do not add 'void' to the ArgTys list.
              break;
            }
          } else if (ArgTy->isHalfType()) {
            // Disallow half FP arguments.
            // FIXME: This really should be in BuildFunctionType.
            S.Diag(Param->getLocation(),
               diag::err_parameters_retval_cannot_have_fp16_type) << 0
            << FixItHint::CreateInsertion(Param->getLocation(), "*");
            D.setInvalidType();
          } else if (!FTI.hasPrototype) {
            if (ArgTy->isPromotableIntegerType()) {
              ArgTy = Context.getPromotedIntegerType(ArgTy);
              Param->setKNRPromoted(true);
            } else if (const BuiltinType* BTy = ArgTy->getAs<BuiltinType>()) {
              if (BTy->getKind() == BuiltinType::Float) {
                ArgTy = Context.DoubleTy;
                Param->setKNRPromoted(true);
              }
            }
          }

          if (LangOpts.ObjCAutoRefCount) {
            bool Consumed = Param->hasAttr<NSConsumedAttr>();
            ConsumedArguments.push_back(Consumed);
            HasAnyConsumedArguments |= Consumed;
          }

          ArgTys.push_back(ArgTy);
        }

        if (HasAnyConsumedArguments)
          EPI.ConsumedArguments = ConsumedArguments.data();

        SmallVector<QualType, 4> Exceptions;
        SmallVector<ParsedType, 2> DynamicExceptions;
        SmallVector<SourceRange, 2> DynamicExceptionRanges;
        Expr *NoexceptExpr = 0;

        if (FTI.getExceptionSpecType() == EST_Dynamic) {
          // FIXME: It's rather inefficient to have to split into two vectors
          // here.
          unsigned N = FTI.NumExceptions;
          DynamicExceptions.reserve(N);
          DynamicExceptionRanges.reserve(N);
          for (unsigned I = 0; I != N; ++I) {
            DynamicExceptions.push_back(FTI.Exceptions[I].Ty);
            DynamicExceptionRanges.push_back(FTI.Exceptions[I].Range);
          }
        } else if (FTI.getExceptionSpecType() == EST_ComputedNoexcept) {
          NoexceptExpr = FTI.NoexceptExpr;
        }

        S.checkExceptionSpecification(FTI.getExceptionSpecType(),
                                      DynamicExceptions,
                                      DynamicExceptionRanges,
                                      NoexceptExpr,
                                      Exceptions,
                                      EPI);

        if (FTI.getExceptionSpecType() == EST_None &&
            ImplicitlyNoexcept && chunkIndex == 0) {
          // Only the outermost chunk is marked noexcept, of course.
          EPI.ExceptionSpecType = EST_BasicNoexcept;
        }

        T = Context.getFunctionType(T, ArgTys.data(), ArgTys.size(), EPI);
      }

      break;
    }
    case DeclaratorChunk::MemberPointer:
      // The scope spec must refer to a class, or be dependent.
      CXXScopeSpec &SS = DeclType.Mem.Scope();
      QualType ClsType;
      if (SS.isInvalid()) {
        // Avoid emitting extra errors if we already errored on the scope.
        D.setInvalidType(true);
      } else if (S.isDependentScopeSpecifier(SS) ||
                 dyn_cast_or_null<CXXRecordDecl>(S.computeDeclContext(SS))) {
        NestedNameSpecifier *NNS
          = static_cast<NestedNameSpecifier*>(SS.getScopeRep());
        NestedNameSpecifier *NNSPrefix = NNS->getPrefix();
        switch (NNS->getKind()) {
        case NestedNameSpecifier::Identifier:
          ClsType = Context.getDependentNameType(ETK_None, NNSPrefix,
                                                 NNS->getAsIdentifier());
          break;

        case NestedNameSpecifier::Namespace:
        case NestedNameSpecifier::NamespaceAlias:
        case NestedNameSpecifier::Global:
          llvm_unreachable("Nested-name-specifier must name a type");

        case NestedNameSpecifier::TypeSpec:
        case NestedNameSpecifier::TypeSpecWithTemplate:
          ClsType = QualType(NNS->getAsType(), 0);
          // Note: if the NNS has a prefix and ClsType is a nondependent
          // TemplateSpecializationType, then the NNS prefix is NOT included
          // in ClsType; hence we wrap ClsType into an ElaboratedType.
          // NOTE: in particular, no wrap occurs if ClsType already is an
          // Elaborated, DependentName, or DependentTemplateSpecialization.
          if (NNSPrefix && isa<TemplateSpecializationType>(NNS->getAsType()))
            ClsType = Context.getElaboratedType(ETK_None, NNSPrefix, ClsType);
          break;
        }
      } else {
        S.Diag(DeclType.Mem.Scope().getBeginLoc(),
             diag::err_illegal_decl_mempointer_in_nonclass)
          << (D.getIdentifier() ? D.getIdentifier()->getName() : "type name")
          << DeclType.Mem.Scope().getRange();
        D.setInvalidType(true);
      }

      if (!ClsType.isNull())
        T = S.BuildMemberPointerType(T, ClsType, DeclType.Loc, D.getIdentifier());
      if (T.isNull()) {
        T = Context.IntTy;
        D.setInvalidType(true);
      } else if (DeclType.Mem.TypeQuals) {
        T = S.BuildQualifiedType(T, DeclType.Loc, DeclType.Mem.TypeQuals);
      }
      break;
    }

    if (T.isNull()) {
      D.setInvalidType(true);
      T = Context.IntTy;
    }

    // See if there are any attributes on this declarator chunk.
    if (AttributeList *attrs = const_cast<AttributeList*>(DeclType.getAttrs()))
      processTypeAttrs(state, T, false, attrs);
  }

  if (LangOpts.CPlusPlus && T->isFunctionType()) {
    const FunctionProtoType *FnTy = T->getAs<FunctionProtoType>();
    assert(FnTy && "Why oh why is there not a FunctionProtoType here?");

    // C++ 8.3.5p4:
    //   A cv-qualifier-seq shall only be part of the function type
    //   for a nonstatic member function, the function type to which a pointer
    //   to member refers, or the top-level function type of a function typedef
    //   declaration.
    //
    // Core issue 547 also allows cv-qualifiers on function types that are
    // top-level template type arguments.
    bool FreeFunction;
    if (!D.getCXXScopeSpec().isSet()) {
      FreeFunction = ((D.getContext() != Declarator::MemberContext &&
                       D.getContext() != Declarator::LambdaExprContext) ||
                      D.getDeclSpec().isFriendSpecified());
    } else {
      DeclContext *DC = S.computeDeclContext(D.getCXXScopeSpec());
      FreeFunction = (DC && !DC->isRecord());
    }

    // C++0x [dcl.constexpr]p8: A constexpr specifier for a non-static member
    // function that is not a constructor declares that function to be const.
    if (D.getDeclSpec().isConstexprSpecified() && !FreeFunction &&
        D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_static &&
        D.getName().getKind() != UnqualifiedId::IK_ConstructorName &&
        D.getName().getKind() != UnqualifiedId::IK_ConstructorTemplateId &&
        !(FnTy->getTypeQuals() & DeclSpec::TQ_const)) {
      // Rebuild function type adding a 'const' qualifier.
      FunctionProtoType::ExtProtoInfo EPI = FnTy->getExtProtoInfo();
      EPI.TypeQuals |= DeclSpec::TQ_const;
      T = Context.getFunctionType(FnTy->getResultType(),
                                  FnTy->arg_type_begin(),
                                  FnTy->getNumArgs(), EPI);
    }

    // C++11 [dcl.fct]p6 (w/DR1417):
    // An attempt to specify a function type with a cv-qualifier-seq or a
    // ref-qualifier (including by typedef-name) is ill-formed unless it is:
    //  - the function type for a non-static member function,
    //  - the function type to which a pointer to member refers,
    //  - the top-level function type of a function typedef declaration or
    //    alias-declaration,
    //  - the type-id in the default argument of a type-parameter, or
    //  - the type-id of a template-argument for a type-parameter
    if (IsQualifiedFunction &&
        !(!FreeFunction &&
          D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_static) &&
        !IsTypedefName &&
        D.getContext() != Declarator::TemplateTypeArgContext) {
      SourceLocation Loc = D.getLocStart();
      SourceRange RemovalRange;
      unsigned I;
      if (D.isFunctionDeclarator(I)) {
        SmallVector<SourceLocation, 4> RemovalLocs;
        const DeclaratorChunk &Chunk = D.getTypeObject(I);
        assert(Chunk.Kind == DeclaratorChunk::Function);
        if (Chunk.Fun.hasRefQualifier())
          RemovalLocs.push_back(Chunk.Fun.getRefQualifierLoc());
        if (Chunk.Fun.TypeQuals & Qualifiers::Const)
          RemovalLocs.push_back(Chunk.Fun.getConstQualifierLoc());
        if (Chunk.Fun.TypeQuals & Qualifiers::Volatile)
          RemovalLocs.push_back(Chunk.Fun.getVolatileQualifierLoc());
        // FIXME: We do not track the location of the __restrict qualifier.
        //if (Chunk.Fun.TypeQuals & Qualifiers::Restrict)
        //  RemovalLocs.push_back(Chunk.Fun.getRestrictQualifierLoc());
        if (!RemovalLocs.empty()) {
          std::sort(RemovalLocs.begin(), RemovalLocs.end(),
                    BeforeThanCompare<SourceLocation>(S.getSourceManager()));
          RemovalRange = SourceRange(RemovalLocs.front(), RemovalLocs.back());
          Loc = RemovalLocs.front();
        }
      }

      S.Diag(Loc, diag::err_invalid_qualified_function_type)
        << FreeFunction << D.isFunctionDeclarator() << T
        << getFunctionQualifiersAsString(FnTy)
        << FixItHint::CreateRemoval(RemovalRange);

      // Strip the cv-qualifiers and ref-qualifiers from the type.
      FunctionProtoType::ExtProtoInfo EPI = FnTy->getExtProtoInfo();
      EPI.TypeQuals = 0;
      EPI.RefQualifier = RQ_None;

      T = Context.getFunctionType(FnTy->getResultType(),
                                  FnTy->arg_type_begin(),
                                  FnTy->getNumArgs(), EPI);
    }
  }

  // Apply any undistributed attributes from the declarator.
  if (!T.isNull())
    if (AttributeList *attrs = D.getAttributes())
      processTypeAttrs(state, T, false, attrs);

  // Diagnose any ignored type attributes.
  if (!T.isNull()) state.diagnoseIgnoredTypeAttrs(T);

  // C++0x [dcl.constexpr]p9:
  //  A constexpr specifier used in an object declaration declares the object
  //  as const.
  if (D.getDeclSpec().isConstexprSpecified() && T->isObjectType()) {
    T.addConst();
  }

  // If there was an ellipsis in the declarator, the declaration declares a
  // parameter pack whose type may be a pack expansion type.
  if (D.hasEllipsis() && !T.isNull()) {
    // C++0x [dcl.fct]p13:
    //   A declarator-id or abstract-declarator containing an ellipsis shall
    //   only be used in a parameter-declaration. Such a parameter-declaration
    //   is a parameter pack (14.5.3). [...]
    switch (D.getContext()) {
    case Declarator::PrototypeContext:
      // C++0x [dcl.fct]p13:
      //   [...] When it is part of a parameter-declaration-clause, the
      //   parameter pack is a function parameter pack (14.5.3). The type T
      //   of the declarator-id of the function parameter pack shall contain
      //   a template parameter pack; each template parameter pack in T is
      //   expanded by the function parameter pack.
      //
      // We represent function parameter packs as function parameters whose
      // type is a pack expansion.
      if (!T->containsUnexpandedParameterPack()) {
        S.Diag(D.getEllipsisLoc(),
             diag::err_function_parameter_pack_without_parameter_packs)
          << T <<  D.getSourceRange();
        D.setEllipsisLoc(SourceLocation());
      } else {
        T = Context.getPackExpansionType(T, llvm::Optional<unsigned>());
      }
      break;

    case Declarator::TemplateParamContext:
      // C++0x [temp.param]p15:
      //   If a template-parameter is a [...] is a parameter-declaration that
      //   declares a parameter pack (8.3.5), then the template-parameter is a
      //   template parameter pack (14.5.3).
      //
      // Note: core issue 778 clarifies that, if there are any unexpanded
      // parameter packs in the type of the non-type template parameter, then
      // it expands those parameter packs.
      if (T->containsUnexpandedParameterPack())
        T = Context.getPackExpansionType(T, llvm::Optional<unsigned>());
      else
        S.Diag(D.getEllipsisLoc(),
               LangOpts.CPlusPlus0x
                 ? diag::warn_cxx98_compat_variadic_templates
                 : diag::ext_variadic_templates);
      break;

    case Declarator::FileContext:
    case Declarator::KNRTypeListContext:
    case Declarator::ObjCParameterContext:  // FIXME: special diagnostic here?
    case Declarator::ObjCResultContext:     // FIXME: special diagnostic here?
    case Declarator::TypeNameContext:
    case Declarator::CXXNewContext:
    case Declarator::AliasDeclContext:
    case Declarator::AliasTemplateContext:
    case Declarator::MemberContext:
    case Declarator::BlockContext:
    case Declarator::ForContext:
    case Declarator::ConditionContext:
    case Declarator::CXXCatchContext:
    case Declarator::ObjCCatchContext:
    case Declarator::BlockLiteralContext:
    case Declarator::LambdaExprContext:
    case Declarator::TrailingReturnContext:
    case Declarator::TemplateTypeArgContext:
      // FIXME: We may want to allow parameter packs in block-literal contexts
      // in the future.
      S.Diag(D.getEllipsisLoc(), diag::err_ellipsis_in_declarator_not_parameter);
      D.setEllipsisLoc(SourceLocation());
      break;
    }
  }

  if (T.isNull())
    return Context.getNullTypeSourceInfo();
  else if (D.isInvalidType())
    return Context.getTrivialTypeSourceInfo(T);

  return S.GetTypeSourceInfoForDeclarator(D, T, TInfo);
}

/// GetTypeForDeclarator - Convert the type for the specified
/// declarator to Type instances.
///
/// The result of this call will never be null, but the associated
/// type may be a null type if there's an unrecoverable error.
TypeSourceInfo *Sema::GetTypeForDeclarator(Declarator &D, Scope *S) {
  // Determine the type of the declarator. Not all forms of declarator
  // have a type.

  TypeProcessingState state(*this, D);

  TypeSourceInfo *ReturnTypeInfo = 0;
  QualType T = GetDeclSpecTypeForDeclarator(state, ReturnTypeInfo);
  if (T.isNull())
    return Context.getNullTypeSourceInfo();

  if (D.isPrototypeContext() && getLangOpts().ObjCAutoRefCount)
    inferARCWriteback(state, T);

  return GetFullTypeForDeclarator(state, T, ReturnTypeInfo);
}

static void transferARCOwnershipToDeclSpec(Sema &S,
                                           QualType &declSpecTy,
                                           Qualifiers::ObjCLifetime ownership) {
  if (declSpecTy->isObjCRetainableType() &&
      declSpecTy.getObjCLifetime() == Qualifiers::OCL_None) {
    Qualifiers qs;
    qs.addObjCLifetime(ownership);
    declSpecTy = S.Context.getQualifiedType(declSpecTy, qs);
  }
}

static void transferARCOwnershipToDeclaratorChunk(TypeProcessingState &state,
                                            Qualifiers::ObjCLifetime ownership,
                                            unsigned chunkIndex) {
  Sema &S = state.getSema();
  Declarator &D = state.getDeclarator();

  // Look for an explicit lifetime attribute.
  DeclaratorChunk &chunk = D.getTypeObject(chunkIndex);
  for (const AttributeList *attr = chunk.getAttrs(); attr;
         attr = attr->getNext())
    if (attr->getKind() == AttributeList::AT_ObjCOwnership)
      return;

  const char *attrStr = 0;
  switch (ownership) {
  case Qualifiers::OCL_None: llvm_unreachable("no ownership!");
  case Qualifiers::OCL_ExplicitNone: attrStr = "none"; break;
  case Qualifiers::OCL_Strong: attrStr = "strong"; break;
  case Qualifiers::OCL_Weak: attrStr = "weak"; break;
  case Qualifiers::OCL_Autoreleasing: attrStr = "autoreleasing"; break;
  }

  // If there wasn't one, add one (with an invalid source location
  // so that we don't make an AttributedType for it).
  AttributeList *attr = D.getAttributePool()
    .create(&S.Context.Idents.get("objc_ownership"), SourceLocation(),
            /*scope*/ 0, SourceLocation(),
            &S.Context.Idents.get(attrStr), SourceLocation(),
            /*args*/ 0, 0, AttributeList::AS_GNU);
  spliceAttrIntoList(*attr, chunk.getAttrListRef());

  // TODO: mark whether we did this inference?
}

/// \brief Used for transferring ownership in casts resulting in l-values.
static void transferARCOwnership(TypeProcessingState &state,
                                 QualType &declSpecTy,
                                 Qualifiers::ObjCLifetime ownership) {
  Sema &S = state.getSema();
  Declarator &D = state.getDeclarator();

  int inner = -1;
  bool hasIndirection = false;
  for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
    DeclaratorChunk &chunk = D.getTypeObject(i);
    switch (chunk.Kind) {
    case DeclaratorChunk::Paren:
      // Ignore parens.
      break;

    case DeclaratorChunk::Array:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::Pointer:
      if (inner != -1)
        hasIndirection = true;
      inner = i;
      break;

    case DeclaratorChunk::BlockPointer:
      if (inner != -1)
        transferARCOwnershipToDeclaratorChunk(state, ownership, i);
      return;

    case DeclaratorChunk::Function:
    case DeclaratorChunk::MemberPointer:
      return;
    }
  }

  if (inner == -1)
    return;

  DeclaratorChunk &chunk = D.getTypeObject(inner);
  if (chunk.Kind == DeclaratorChunk::Pointer) {
    if (declSpecTy->isObjCRetainableType())
      return transferARCOwnershipToDeclSpec(S, declSpecTy, ownership);
    if (declSpecTy->isObjCObjectType() && hasIndirection)
      return transferARCOwnershipToDeclaratorChunk(state, ownership, inner);
  } else {
    assert(chunk.Kind == DeclaratorChunk::Array ||
           chunk.Kind == DeclaratorChunk::Reference);
    return transferARCOwnershipToDeclSpec(S, declSpecTy, ownership);
  }
}

TypeSourceInfo *Sema::GetTypeForDeclaratorCast(Declarator &D, QualType FromTy) {
  TypeProcessingState state(*this, D);

  TypeSourceInfo *ReturnTypeInfo = 0;
  QualType declSpecTy = GetDeclSpecTypeForDeclarator(state, ReturnTypeInfo);
  if (declSpecTy.isNull())
    return Context.getNullTypeSourceInfo();

  if (getLangOpts().ObjCAutoRefCount) {
    Qualifiers::ObjCLifetime ownership = Context.getInnerObjCOwnership(FromTy);
    if (ownership != Qualifiers::OCL_None)
      transferARCOwnership(state, declSpecTy, ownership);
  }

  return GetFullTypeForDeclarator(state, declSpecTy, ReturnTypeInfo);
}

/// Map an AttributedType::Kind to an AttributeList::Kind.
static AttributeList::Kind getAttrListKind(AttributedType::Kind kind) {
  switch (kind) {
  case AttributedType::attr_address_space:
    return AttributeList::AT_AddressSpace;
  case AttributedType::attr_regparm:
    return AttributeList::AT_Regparm;
  case AttributedType::attr_vector_size:
    return AttributeList::AT_VectorSize;
  case AttributedType::attr_neon_vector_type:
    return AttributeList::AT_NeonVectorType;
  case AttributedType::attr_neon_polyvector_type:
    return AttributeList::AT_NeonPolyVectorType;
  case AttributedType::attr_objc_gc:
    return AttributeList::AT_ObjCGC;
  case AttributedType::attr_objc_ownership:
    return AttributeList::AT_ObjCOwnership;
  case AttributedType::attr_noreturn:
    return AttributeList::AT_NoReturn;
  case AttributedType::attr_cdecl:
    return AttributeList::AT_CDecl;
  case AttributedType::attr_fastcall:
    return AttributeList::AT_FastCall;
  case AttributedType::attr_stdcall:
    return AttributeList::AT_StdCall;
  case AttributedType::attr_thiscall:
    return AttributeList::AT_ThisCall;
  case AttributedType::attr_pascal:
    return AttributeList::AT_Pascal;
  case AttributedType::attr_pcs:
    return AttributeList::AT_Pcs;
  }
  llvm_unreachable("unexpected attribute kind!");
}

static void fillAttributedTypeLoc(AttributedTypeLoc TL,
                                  const AttributeList *attrs) {
  AttributedType::Kind kind = TL.getAttrKind();

  assert(attrs && "no type attributes in the expected location!");
  AttributeList::Kind parsedKind = getAttrListKind(kind);
  while (attrs->getKind() != parsedKind) {
    attrs = attrs->getNext();
    assert(attrs && "no matching attribute in expected location!");
  }

  TL.setAttrNameLoc(attrs->getLoc());
  if (TL.hasAttrExprOperand())
    TL.setAttrExprOperand(attrs->getArg(0));
  else if (TL.hasAttrEnumOperand())
    TL.setAttrEnumOperandLoc(attrs->getParameterLoc());

  // FIXME: preserve this information to here.
  if (TL.hasAttrOperand())
    TL.setAttrOperandParensRange(SourceRange());
}

namespace {
  class TypeSpecLocFiller : public TypeLocVisitor<TypeSpecLocFiller> {
    ASTContext &Context;
    const DeclSpec &DS;

  public:
    TypeSpecLocFiller(ASTContext &Context, const DeclSpec &DS)
      : Context(Context), DS(DS) {}

    void VisitAttributedTypeLoc(AttributedTypeLoc TL) {
      fillAttributedTypeLoc(TL, DS.getAttributes().getList());
      Visit(TL.getModifiedLoc());
    }
    void VisitQualifiedTypeLoc(QualifiedTypeLoc TL) {
      Visit(TL.getUnqualifiedLoc());
    }
    void VisitTypedefTypeLoc(TypedefTypeLoc TL) {
      TL.setNameLoc(DS.getTypeSpecTypeLoc());
    }
    void VisitObjCInterfaceTypeLoc(ObjCInterfaceTypeLoc TL) {
      TL.setNameLoc(DS.getTypeSpecTypeLoc());
      // FIXME. We should have DS.getTypeSpecTypeEndLoc(). But, it requires
      // addition field. What we have is good enough for dispay of location
      // of 'fixit' on interface name.
      TL.setNameEndLoc(DS.getLocEnd());
    }
    void VisitObjCObjectTypeLoc(ObjCObjectTypeLoc TL) {
      // Handle the base type, which might not have been written explicitly.
      if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
        TL.setHasBaseTypeAsWritten(false);
        TL.getBaseLoc().initialize(Context, SourceLocation());
      } else {
        TL.setHasBaseTypeAsWritten(true);
        Visit(TL.getBaseLoc());
      }

      // Protocol qualifiers.
      if (DS.getProtocolQualifiers()) {
        assert(TL.getNumProtocols() > 0);
        assert(TL.getNumProtocols() == DS.getNumProtocolQualifiers());
        TL.setLAngleLoc(DS.getProtocolLAngleLoc());
        TL.setRAngleLoc(DS.getSourceRange().getEnd());
        for (unsigned i = 0, e = DS.getNumProtocolQualifiers(); i != e; ++i)
          TL.setProtocolLoc(i, DS.getProtocolLocs()[i]);
      } else {
        assert(TL.getNumProtocols() == 0);
        TL.setLAngleLoc(SourceLocation());
        TL.setRAngleLoc(SourceLocation());
      }
    }
    void VisitObjCObjectPointerTypeLoc(ObjCObjectPointerTypeLoc TL) {
      TL.setStarLoc(SourceLocation());
      Visit(TL.getPointeeLoc());
    }
    void VisitTemplateSpecializationTypeLoc(TemplateSpecializationTypeLoc TL) {
      TypeSourceInfo *TInfo = 0;
      Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);

      // If we got no declarator info from previous Sema routines,
      // just fill with the typespec loc.
      if (!TInfo) {
        TL.initialize(Context, DS.getTypeSpecTypeNameLoc());
        return;
      }

      TypeLoc OldTL = TInfo->getTypeLoc();
      if (TInfo->getType()->getAs<ElaboratedType>()) {
        ElaboratedTypeLoc ElabTL = cast<ElaboratedTypeLoc>(OldTL);
        TemplateSpecializationTypeLoc NamedTL =
          cast<TemplateSpecializationTypeLoc>(ElabTL.getNamedTypeLoc());
        TL.copy(NamedTL);
      }
      else
        TL.copy(cast<TemplateSpecializationTypeLoc>(OldTL));
    }
    void VisitTypeOfExprTypeLoc(TypeOfExprTypeLoc TL) {
      assert(DS.getTypeSpecType() == DeclSpec::TST_typeofExpr);
      TL.setTypeofLoc(DS.getTypeSpecTypeLoc());
      TL.setParensRange(DS.getTypeofParensRange());
    }
    void VisitTypeOfTypeLoc(TypeOfTypeLoc TL) {
      assert(DS.getTypeSpecType() == DeclSpec::TST_typeofType);
      TL.setTypeofLoc(DS.getTypeSpecTypeLoc());
      TL.setParensRange(DS.getTypeofParensRange());
      assert(DS.getRepAsType());
      TypeSourceInfo *TInfo = 0;
      Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);
      TL.setUnderlyingTInfo(TInfo);
    }
    void VisitUnaryTransformTypeLoc(UnaryTransformTypeLoc TL) {
      // FIXME: This holds only because we only have one unary transform.
      assert(DS.getTypeSpecType() == DeclSpec::TST_underlyingType);
      TL.setKWLoc(DS.getTypeSpecTypeLoc());
      TL.setParensRange(DS.getTypeofParensRange());
      assert(DS.getRepAsType());
      TypeSourceInfo *TInfo = 0;
      Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);
      TL.setUnderlyingTInfo(TInfo);
    }
    void VisitBuiltinTypeLoc(BuiltinTypeLoc TL) {
      // By default, use the source location of the type specifier.
      TL.setBuiltinLoc(DS.getTypeSpecTypeLoc());
      if (TL.needsExtraLocalData()) {
        // Set info for the written builtin specifiers.
        TL.getWrittenBuiltinSpecs() = DS.getWrittenBuiltinSpecs();
        // Try to have a meaningful source location.
        if (TL.getWrittenSignSpec() != TSS_unspecified)
          // Sign spec loc overrides the others (e.g., 'unsigned long').
          TL.setBuiltinLoc(DS.getTypeSpecSignLoc());
        else if (TL.getWrittenWidthSpec() != TSW_unspecified)
          // Width spec loc overrides type spec loc (e.g., 'short int').
          TL.setBuiltinLoc(DS.getTypeSpecWidthLoc());
      }
    }
    void VisitElaboratedTypeLoc(ElaboratedTypeLoc TL) {
      ElaboratedTypeKeyword Keyword
        = TypeWithKeyword::getKeywordForTypeSpec(DS.getTypeSpecType());
      if (DS.getTypeSpecType() == TST_typename) {
        TypeSourceInfo *TInfo = 0;
        Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);
        if (TInfo) {
          TL.copy(cast<ElaboratedTypeLoc>(TInfo->getTypeLoc()));
          return;
        }
      }
      TL.setElaboratedKeywordLoc(Keyword != ETK_None
                                 ? DS.getTypeSpecTypeLoc()
                                 : SourceLocation());
      const CXXScopeSpec& SS = DS.getTypeSpecScope();
      TL.setQualifierLoc(SS.getWithLocInContext(Context));
      Visit(TL.getNextTypeLoc().getUnqualifiedLoc());
    }
    void VisitDependentNameTypeLoc(DependentNameTypeLoc TL) {
      assert(DS.getTypeSpecType() == TST_typename);
      TypeSourceInfo *TInfo = 0;
      Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);
      assert(TInfo);
      TL.copy(cast<DependentNameTypeLoc>(TInfo->getTypeLoc()));
    }
    void VisitDependentTemplateSpecializationTypeLoc(
                                 DependentTemplateSpecializationTypeLoc TL) {
      assert(DS.getTypeSpecType() == TST_typename);
      TypeSourceInfo *TInfo = 0;
      Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);
      assert(TInfo);
      TL.copy(cast<DependentTemplateSpecializationTypeLoc>(
                TInfo->getTypeLoc()));
    }
    void VisitTagTypeLoc(TagTypeLoc TL) {
      TL.setNameLoc(DS.getTypeSpecTypeNameLoc());
    }
    void VisitAtomicTypeLoc(AtomicTypeLoc TL) {
      TL.setKWLoc(DS.getTypeSpecTypeLoc());
      TL.setParensRange(DS.getTypeofParensRange());

      TypeSourceInfo *TInfo = 0;
      Sema::GetTypeFromParser(DS.getRepAsType(), &TInfo);
      TL.getValueLoc().initializeFullCopy(TInfo->getTypeLoc());
    }

    void VisitTypeLoc(TypeLoc TL) {
      // FIXME: add other typespec types and change this to an assert.
      TL.initialize(Context, DS.getTypeSpecTypeLoc());
    }
  };

  class DeclaratorLocFiller : public TypeLocVisitor<DeclaratorLocFiller> {
    ASTContext &Context;
    const DeclaratorChunk &Chunk;

  public:
    DeclaratorLocFiller(ASTContext &Context, const DeclaratorChunk &Chunk)
      : Context(Context), Chunk(Chunk) {}

    void VisitQualifiedTypeLoc(QualifiedTypeLoc TL) {
      llvm_unreachable("qualified type locs not expected here!");
    }

    void VisitAttributedTypeLoc(AttributedTypeLoc TL) {
      fillAttributedTypeLoc(TL, Chunk.getAttrs());
    }
    void VisitBlockPointerTypeLoc(BlockPointerTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::BlockPointer);
      TL.setCaretLoc(Chunk.Loc);
    }
    void VisitPointerTypeLoc(PointerTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::Pointer);
      TL.setStarLoc(Chunk.Loc);
    }
    void VisitObjCObjectPointerTypeLoc(ObjCObjectPointerTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::Pointer);
      TL.setStarLoc(Chunk.Loc);
    }
    void VisitMemberPointerTypeLoc(MemberPointerTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::MemberPointer);
      const CXXScopeSpec& SS = Chunk.Mem.Scope();
      NestedNameSpecifierLoc NNSLoc = SS.getWithLocInContext(Context);

      const Type* ClsTy = TL.getClass();
      QualType ClsQT = QualType(ClsTy, 0);
      TypeSourceInfo *ClsTInfo = Context.CreateTypeSourceInfo(ClsQT, 0);
      // Now copy source location info into the type loc component.
      TypeLoc ClsTL = ClsTInfo->getTypeLoc();
      switch (NNSLoc.getNestedNameSpecifier()->getKind()) {
      case NestedNameSpecifier::Identifier:
        assert(isa<DependentNameType>(ClsTy) && "Unexpected TypeLoc");
        {
          DependentNameTypeLoc DNTLoc = cast<DependentNameTypeLoc>(ClsTL);
          DNTLoc.setElaboratedKeywordLoc(SourceLocation());
          DNTLoc.setQualifierLoc(NNSLoc.getPrefix());
          DNTLoc.setNameLoc(NNSLoc.getLocalBeginLoc());
        }
        break;

      case NestedNameSpecifier::TypeSpec:
      case NestedNameSpecifier::TypeSpecWithTemplate:
        if (isa<ElaboratedType>(ClsTy)) {
          ElaboratedTypeLoc ETLoc = *cast<ElaboratedTypeLoc>(&ClsTL);
          ETLoc.setElaboratedKeywordLoc(SourceLocation());
          ETLoc.setQualifierLoc(NNSLoc.getPrefix());
          TypeLoc NamedTL = ETLoc.getNamedTypeLoc();
          NamedTL.initializeFullCopy(NNSLoc.getTypeLoc());
        } else {
          ClsTL.initializeFullCopy(NNSLoc.getTypeLoc());
        }
        break;

      case NestedNameSpecifier::Namespace:
      case NestedNameSpecifier::NamespaceAlias:
      case NestedNameSpecifier::Global:
        llvm_unreachable("Nested-name-specifier must name a type");
      }

      // Finally fill in MemberPointerLocInfo fields.
      TL.setStarLoc(Chunk.Loc);
      TL.setClassTInfo(ClsTInfo);
    }
    void VisitLValueReferenceTypeLoc(LValueReferenceTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::Reference);
      // 'Amp' is misleading: this might have been originally
      /// spelled with AmpAmp.
      TL.setAmpLoc(Chunk.Loc);
    }
    void VisitRValueReferenceTypeLoc(RValueReferenceTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::Reference);
      assert(!Chunk.Ref.LValueRef);
      TL.setAmpAmpLoc(Chunk.Loc);
    }
    void VisitArrayTypeLoc(ArrayTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::Array);
      TL.setLBracketLoc(Chunk.Loc);
      TL.setRBracketLoc(Chunk.EndLoc);
      TL.setSizeExpr(static_cast<Expr*>(Chunk.Arr.NumElts));
    }
    void VisitFunctionTypeLoc(FunctionTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::Function);
      TL.setLocalRangeBegin(Chunk.Loc);
      TL.setLocalRangeEnd(Chunk.EndLoc);

      const DeclaratorChunk::FunctionTypeInfo &FTI = Chunk.Fun;
      for (unsigned i = 0, e = TL.getNumArgs(), tpi = 0; i != e; ++i) {
        ParmVarDecl *Param = cast<ParmVarDecl>(FTI.ArgInfo[i].Param);
        TL.setArg(tpi++, Param);
      }
      // FIXME: exception specs
    }
    void VisitParenTypeLoc(ParenTypeLoc TL) {
      assert(Chunk.Kind == DeclaratorChunk::Paren);
      TL.setLParenLoc(Chunk.Loc);
      TL.setRParenLoc(Chunk.EndLoc);
    }

    void VisitTypeLoc(TypeLoc TL) {
      llvm_unreachable("unsupported TypeLoc kind in declarator!");
    }
  };
}

/// \brief Create and instantiate a TypeSourceInfo with type source information.
///
/// \param T QualType referring to the type as written in source code.
///
/// \param ReturnTypeInfo For declarators whose return type does not show
/// up in the normal place in the declaration specifiers (such as a C++
/// conversion function), this pointer will refer to a type source information
/// for that return type.
TypeSourceInfo *
Sema::GetTypeSourceInfoForDeclarator(Declarator &D, QualType T,
                                     TypeSourceInfo *ReturnTypeInfo) {
  TypeSourceInfo *TInfo = Context.CreateTypeSourceInfo(T);
  UnqualTypeLoc CurrTL = TInfo->getTypeLoc().getUnqualifiedLoc();

  // Handle parameter packs whose type is a pack expansion.
  if (isa<PackExpansionType>(T)) {
    cast<PackExpansionTypeLoc>(CurrTL).setEllipsisLoc(D.getEllipsisLoc());
    CurrTL = CurrTL.getNextTypeLoc().getUnqualifiedLoc();
  }

  for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
    while (isa<AttributedTypeLoc>(CurrTL)) {
      AttributedTypeLoc TL = cast<AttributedTypeLoc>(CurrTL);
      fillAttributedTypeLoc(TL, D.getTypeObject(i).getAttrs());
      CurrTL = TL.getNextTypeLoc().getUnqualifiedLoc();
    }

    DeclaratorLocFiller(Context, D.getTypeObject(i)).Visit(CurrTL);
    CurrTL = CurrTL.getNextTypeLoc().getUnqualifiedLoc();
  }

  // If we have different source information for the return type, use
  // that.  This really only applies to C++ conversion functions.
  if (ReturnTypeInfo) {
    TypeLoc TL = ReturnTypeInfo->getTypeLoc();
    assert(TL.getFullDataSize() == CurrTL.getFullDataSize());
    memcpy(CurrTL.getOpaqueData(), TL.getOpaqueData(), TL.getFullDataSize());
  } else {
    TypeSpecLocFiller(Context, D.getDeclSpec()).Visit(CurrTL);
  }

  return TInfo;
}

/// \brief Create a LocInfoType to hold the given QualType and TypeSourceInfo.
ParsedType Sema::CreateParsedType(QualType T, TypeSourceInfo *TInfo) {
  // FIXME: LocInfoTypes are "transient", only needed for passing to/from Parser
  // and Sema during declaration parsing. Try deallocating/caching them when
  // it's appropriate, instead of allocating them and keeping them around.
  LocInfoType *LocT = (LocInfoType*)BumpAlloc.Allocate(sizeof(LocInfoType),
                                                       TypeAlignment);
  new (LocT) LocInfoType(T, TInfo);
  assert(LocT->getTypeClass() != T->getTypeClass() &&
         "LocInfoType's TypeClass conflicts with an existing Type class");
  return ParsedType::make(QualType(LocT, 0));
}

void LocInfoType::getAsStringInternal(std::string &Str,
                                      const PrintingPolicy &Policy) const {
  llvm_unreachable("LocInfoType leaked into the type system; an opaque TypeTy*"
         " was used directly instead of getting the QualType through"
         " GetTypeFromParser");
}

TypeResult Sema::ActOnTypeName(Scope *S, Declarator &D) {
  // C99 6.7.6: Type names have no identifier.  This is already validated by
  // the parser.
  assert(D.getIdentifier() == 0 && "Type name should have no identifier!");

  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
  QualType T = TInfo->getType();
  if (D.isInvalidType())
    return true;

  // Make sure there are no unused decl attributes on the declarator.
  // We don't want to do this for ObjC parameters because we're going
  // to apply them to the actual parameter declaration.
  if (D.getContext() != Declarator::ObjCParameterContext)
    checkUnusedDeclAttributes(D);

  if (getLangOpts().CPlusPlus) {
    // Check that there are no default arguments (C++ only).
    CheckExtraCXXDefaultArguments(D);
  }

  return CreateParsedType(T, TInfo);
}

ParsedType Sema::ActOnObjCInstanceType(SourceLocation Loc) {
  QualType T = Context.getObjCInstanceType();
  TypeSourceInfo *TInfo = Context.getTrivialTypeSourceInfo(T, Loc);
  return CreateParsedType(T, TInfo);
}


//===----------------------------------------------------------------------===//
// Type Attribute Processing
//===----------------------------------------------------------------------===//

/// HandleAddressSpaceTypeAttribute - Process an address_space attribute on the
/// specified type.  The attribute contains 1 argument, the id of the address
/// space for the type.
static void HandleAddressSpaceTypeAttribute(QualType &Type,
                                            const AttributeList &Attr, Sema &S){

  // If this type is already address space qualified, reject it.
  // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified by
  // qualifiers for two or more different address spaces."
  if (Type.getAddressSpace()) {
    S.Diag(Attr.getLoc(), diag::err_attribute_address_multiple_qualifiers);
    Attr.setInvalid();
    return;
  }

  // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "A function type shall not be
  // qualified by an address-space qualifier."
  if (Type->isFunctionType()) {
    S.Diag(Attr.getLoc(), diag::err_attribute_address_function_type);
    Attr.setInvalid();
    return;
  }

  // Check the attribute arguments.
  if (Attr.getNumArgs() != 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
    Attr.setInvalid();
    return;
  }
  Expr *ASArgExpr = static_cast<Expr *>(Attr.getArg(0));
  llvm::APSInt addrSpace(32);
  if (ASArgExpr->isTypeDependent() || ASArgExpr->isValueDependent() ||
      !ASArgExpr->isIntegerConstantExpr(addrSpace, S.Context)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_address_space_not_int)
      << ASArgExpr->getSourceRange();
    Attr.setInvalid();
    return;
  }

  // Bounds checking.
  if (addrSpace.isSigned()) {
    if (addrSpace.isNegative()) {
      S.Diag(Attr.getLoc(), diag::err_attribute_address_space_negative)
        << ASArgExpr->getSourceRange();
      Attr.setInvalid();
      return;
    }
    addrSpace.setIsSigned(false);
  }
  llvm::APSInt max(addrSpace.getBitWidth());
  max = Qualifiers::MaxAddressSpace;
  if (addrSpace > max) {
    S.Diag(Attr.getLoc(), diag::err_attribute_address_space_too_high)
      << Qualifiers::MaxAddressSpace << ASArgExpr->getSourceRange();
    Attr.setInvalid();
    return;
  }

  unsigned ASIdx = static_cast<unsigned>(addrSpace.getZExtValue());
  Type = S.Context.getAddrSpaceQualType(Type, ASIdx);
}

/// Does this type have a "direct" ownership qualifier?  That is,
/// is it written like "__strong id", as opposed to something like
/// "typeof(foo)", where that happens to be strong?
static bool hasDirectOwnershipQualifier(QualType type) {
  // Fast path: no qualifier at all.
  assert(type.getQualifiers().hasObjCLifetime());

  while (true) {
    // __strong id
    if (const AttributedType *attr = dyn_cast<AttributedType>(type)) {
      if (attr->getAttrKind() == AttributedType::attr_objc_ownership)
        return true;

      type = attr->getModifiedType();

    // X *__strong (...)
    } else if (const ParenType *paren = dyn_cast<ParenType>(type)) {
      type = paren->getInnerType();

    // That's it for things we want to complain about.  In particular,
    // we do not want to look through typedefs, typeof(expr),
    // typeof(type), or any other way that the type is somehow
    // abstracted.
    } else {

      return false;
    }
  }
}

/// handleObjCOwnershipTypeAttr - Process an objc_ownership
/// attribute on the specified type.
///
/// Returns 'true' if the attribute was handled.
static bool handleObjCOwnershipTypeAttr(TypeProcessingState &state,
                                       AttributeList &attr,
                                       QualType &type) {
  bool NonObjCPointer = false;

  if (!type->isDependentType()) {
    if (const PointerType *ptr = type->getAs<PointerType>()) {
      QualType pointee = ptr->getPointeeType();
      if (pointee->isObjCRetainableType() || pointee->isPointerType())
        return false;
      // It is important not to lose the source info that there was an attribute
      // applied to non-objc pointer. We will create an attributed type but
      // its type will be the same as the original type.
      NonObjCPointer = true;
    } else if (!type->isObjCRetainableType()) {
      return false;
    }
  }

  Sema &S = state.getSema();
  SourceLocation AttrLoc = attr.getLoc();
  if (AttrLoc.isMacroID())
    AttrLoc = S.getSourceManager().getImmediateExpansionRange(AttrLoc).first;

  if (!attr.getParameterName()) {
    S.Diag(AttrLoc, diag::err_attribute_argument_n_not_string)
      << "objc_ownership" << 1;
    attr.setInvalid();
    return true;
  }

  // Consume lifetime attributes without further comment outside of
  // ARC mode.
  if (!S.getLangOpts().ObjCAutoRefCount)
    return true;

  Qualifiers::ObjCLifetime lifetime;
  if (attr.getParameterName()->isStr("none"))
    lifetime = Qualifiers::OCL_ExplicitNone;
  else if (attr.getParameterName()->isStr("strong"))
    lifetime = Qualifiers::OCL_Strong;
  else if (attr.getParameterName()->isStr("weak"))
    lifetime = Qualifiers::OCL_Weak;
  else if (attr.getParameterName()->isStr("autoreleasing"))
    lifetime = Qualifiers::OCL_Autoreleasing;
  else {
    S.Diag(AttrLoc, diag::warn_attribute_type_not_supported)
      << "objc_ownership" << attr.getParameterName();
    attr.setInvalid();
    return true;
  }

  SplitQualType underlyingType = type.split();

  // Check for redundant/conflicting ownership qualifiers.
  if (Qualifiers::ObjCLifetime previousLifetime
        = type.getQualifiers().getObjCLifetime()) {
    // If it's written directly, that's an error.
    if (hasDirectOwnershipQualifier(type)) {
      S.Diag(AttrLoc, diag::err_attr_objc_ownership_redundant)
        << type;
      return true;
    }

    // Otherwise, if the qualifiers actually conflict, pull sugar off
    // until we reach a type that is directly qualified.
    if (previousLifetime != lifetime) {
      // This should always terminate: the canonical type is
      // qualified, so some bit of sugar must be hiding it.
      while (!underlyingType.Quals.hasObjCLifetime()) {
        underlyingType = underlyingType.getSingleStepDesugaredType();
      }
      underlyingType.Quals.removeObjCLifetime();
    }
  }

  underlyingType.Quals.addObjCLifetime(lifetime);

  if (NonObjCPointer) {
    StringRef name = attr.getName()->getName();
    switch (lifetime) {
    case Qualifiers::OCL_None:
    case Qualifiers::OCL_ExplicitNone:
      break;
    case Qualifiers::OCL_Strong: name = "__strong"; break;
    case Qualifiers::OCL_Weak: name = "__weak"; break;
    case Qualifiers::OCL_Autoreleasing: name = "__autoreleasing"; break;
    }
    S.Diag(AttrLoc, diag::warn_objc_object_attribute_wrong_type)
      << name << type;
  }

  QualType origType = type;
  if (!NonObjCPointer)
    type = S.Context.getQualifiedType(underlyingType);

  // If we have a valid source location for the attribute, use an
  // AttributedType instead.
  if (AttrLoc.isValid())
    type = S.Context.getAttributedType(AttributedType::attr_objc_ownership,
                                       origType, type);

  // Forbid __weak if the runtime doesn't support it.
  if (lifetime == Qualifiers::OCL_Weak &&
      !S.getLangOpts().ObjCRuntimeHasWeak && !NonObjCPointer) {

    // Actually, delay this until we know what we're parsing.
    if (S.DelayedDiagnostics.shouldDelayDiagnostics()) {
      S.DelayedDiagnostics.add(
          sema::DelayedDiagnostic::makeForbiddenType(
              S.getSourceManager().getExpansionLoc(AttrLoc),
              diag::err_arc_weak_no_runtime, type, /*ignored*/ 0));
    } else {
      S.Diag(AttrLoc, diag::err_arc_weak_no_runtime);
    }

    attr.setInvalid();
    return true;
  }

  // Forbid __weak for class objects marked as
  // objc_arc_weak_reference_unavailable
  if (lifetime == Qualifiers::OCL_Weak) {
    QualType T = type;
    while (const PointerType *ptr = T->getAs<PointerType>())
      T = ptr->getPointeeType();
    if (const ObjCObjectPointerType *ObjT = T->getAs<ObjCObjectPointerType>()) {
      ObjCInterfaceDecl *Class = ObjT->getInterfaceDecl();
      if (Class->isArcWeakrefUnavailable()) {
          S.Diag(AttrLoc, diag::err_arc_unsupported_weak_class);
          S.Diag(ObjT->getInterfaceDecl()->getLocation(),
                 diag::note_class_declared);
      }
    }
  }

  return true;
}

/// handleObjCGCTypeAttr - Process the __attribute__((objc_gc)) type
/// attribute on the specified type.  Returns true to indicate that
/// the attribute was handled, false to indicate that the type does
/// not permit the attribute.
static bool handleObjCGCTypeAttr(TypeProcessingState &state,
                                 AttributeList &attr,
                                 QualType &type) {
  Sema &S = state.getSema();

  // Delay if this isn't some kind of pointer.
  if (!type->isPointerType() &&
      !type->isObjCObjectPointerType() &&
      !type->isBlockPointerType())
    return false;

  if (type.getObjCGCAttr() != Qualifiers::GCNone) {
    S.Diag(attr.getLoc(), diag::err_attribute_multiple_objc_gc);
    attr.setInvalid();
    return true;
  }

  // Check the attribute arguments.
  if (!attr.getParameterName()) {
    S.Diag(attr.getLoc(), diag::err_attribute_argument_n_not_string)
      << "objc_gc" << 1;
    attr.setInvalid();
    return true;
  }
  Qualifiers::GC GCAttr;
  if (attr.getNumArgs() != 0) {
    S.Diag(attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
    attr.setInvalid();
    return true;
  }
  if (attr.getParameterName()->isStr("weak"))
    GCAttr = Qualifiers::Weak;
  else if (attr.getParameterName()->isStr("strong"))
    GCAttr = Qualifiers::Strong;
  else {
    S.Diag(attr.getLoc(), diag::warn_attribute_type_not_supported)
      << "objc_gc" << attr.getParameterName();
    attr.setInvalid();
    return true;
  }

  QualType origType = type;
  type = S.Context.getObjCGCQualType(origType, GCAttr);

  // Make an attributed type to preserve the source information.
  if (attr.getLoc().isValid())
    type = S.Context.getAttributedType(AttributedType::attr_objc_gc,
                                       origType, type);

  return true;
}

namespace {
  /// A helper class to unwrap a type down to a function for the
  /// purposes of applying attributes there.
  ///
  /// Use:
  ///   FunctionTypeUnwrapper unwrapped(SemaRef, T);
  ///   if (unwrapped.isFunctionType()) {
  ///     const FunctionType *fn = unwrapped.get();
  ///     // change fn somehow
  ///     T = unwrapped.wrap(fn);
  ///   }
  struct FunctionTypeUnwrapper {
    enum WrapKind {
      Desugar,
      Parens,
      Pointer,
      BlockPointer,
      Reference,
      MemberPointer
    };

    QualType Original;
    const FunctionType *Fn;
    SmallVector<unsigned char /*WrapKind*/, 8> Stack;

    FunctionTypeUnwrapper(Sema &S, QualType T) : Original(T) {
      while (true) {
        const Type *Ty = T.getTypePtr();
        if (isa<FunctionType>(Ty)) {
          Fn = cast<FunctionType>(Ty);
          return;
        } else if (isa<ParenType>(Ty)) {
          T = cast<ParenType>(Ty)->getInnerType();
          Stack.push_back(Parens);
        } else if (isa<PointerType>(Ty)) {
          T = cast<PointerType>(Ty)->getPointeeType();
          Stack.push_back(Pointer);
        } else if (isa<BlockPointerType>(Ty)) {
          T = cast<BlockPointerType>(Ty)->getPointeeType();
          Stack.push_back(BlockPointer);
        } else if (isa<MemberPointerType>(Ty)) {
          T = cast<MemberPointerType>(Ty)->getPointeeType();
          Stack.push_back(MemberPointer);
        } else if (isa<ReferenceType>(Ty)) {
          T = cast<ReferenceType>(Ty)->getPointeeType();
          Stack.push_back(Reference);
        } else {
          const Type *DTy = Ty->getUnqualifiedDesugaredType();
          if (Ty == DTy) {
            Fn = 0;
            return;
          }

          T = QualType(DTy, 0);
          Stack.push_back(Desugar);
        }
      }
    }

    bool isFunctionType() const { return (Fn != 0); }
    const FunctionType *get() const { return Fn; }

    QualType wrap(Sema &S, const FunctionType *New) {
      // If T wasn't modified from the unwrapped type, do nothing.
      if (New == get()) return Original;

      Fn = New;
      return wrap(S.Context, Original, 0);
    }

  private:
    QualType wrap(ASTContext &C, QualType Old, unsigned I) {
      if (I == Stack.size())
        return C.getQualifiedType(Fn, Old.getQualifiers());

      // Build up the inner type, applying the qualifiers from the old
      // type to the new type.
      SplitQualType SplitOld = Old.split();

      // As a special case, tail-recurse if there are no qualifiers.
      if (SplitOld.Quals.empty())
        return wrap(C, SplitOld.Ty, I);
      return C.getQualifiedType(wrap(C, SplitOld.Ty, I), SplitOld.Quals);
    }

    QualType wrap(ASTContext &C, const Type *Old, unsigned I) {
      if (I == Stack.size()) return QualType(Fn, 0);

      switch (static_cast<WrapKind>(Stack[I++])) {
      case Desugar:
        // This is the point at which we potentially lose source
        // information.
        return wrap(C, Old->getUnqualifiedDesugaredType(), I);

      case Parens: {
        QualType New = wrap(C, cast<ParenType>(Old)->getInnerType(), I);
        return C.getParenType(New);
      }

      case Pointer: {
        QualType New = wrap(C, cast<PointerType>(Old)->getPointeeType(), I);
        return C.getPointerType(New);
      }

      case BlockPointer: {
        QualType New = wrap(C, cast<BlockPointerType>(Old)->getPointeeType(),I);
        return C.getBlockPointerType(New);
      }

      case MemberPointer: {
        const MemberPointerType *OldMPT = cast<MemberPointerType>(Old);
        QualType New = wrap(C, OldMPT->getPointeeType(), I);
        return C.getMemberPointerType(New, OldMPT->getClass());
      }

      case Reference: {
        const ReferenceType *OldRef = cast<ReferenceType>(Old);
        QualType New = wrap(C, OldRef->getPointeeType(), I);
        if (isa<LValueReferenceType>(OldRef))
          return C.getLValueReferenceType(New, OldRef->isSpelledAsLValue());
        else
          return C.getRValueReferenceType(New);
      }
      }

      llvm_unreachable("unknown wrapping kind");
    }
  };
}

/// Process an individual function attribute.  Returns true to
/// indicate that the attribute was handled, false if it wasn't.
static bool handleFunctionTypeAttr(TypeProcessingState &state,
                                   AttributeList &attr,
                                   QualType &type) {
  Sema &S = state.getSema();

  FunctionTypeUnwrapper unwrapped(S, type);

  if (attr.getKind() == AttributeList::AT_NoReturn) {
    if (S.CheckNoReturnAttr(attr))
      return true;

    // Delay if this is not a function type.
    if (!unwrapped.isFunctionType())
      return false;

    // Otherwise we can process right away.
    FunctionType::ExtInfo EI = unwrapped.get()->getExtInfo().withNoReturn(true);
    type = unwrapped.wrap(S, S.Context.adjustFunctionType(unwrapped.get(), EI));
    return true;
  }

  // ns_returns_retained is not always a type attribute, but if we got
  // here, we're treating it as one right now.
  if (attr.getKind() == AttributeList::AT_NSReturnsRetained) {
    assert(S.getLangOpts().ObjCAutoRefCount &&
           "ns_returns_retained treated as type attribute in non-ARC");
    if (attr.getNumArgs()) return true;

    // Delay if this is not a function type.
    if (!unwrapped.isFunctionType())
      return false;

    FunctionType::ExtInfo EI
      = unwrapped.get()->getExtInfo().withProducesResult(true);
    type = unwrapped.wrap(S, S.Context.adjustFunctionType(unwrapped.get(), EI));
    return true;
  }

  if (attr.getKind() == AttributeList::AT_Regparm) {
    unsigned value;
    if (S.CheckRegparmAttr(attr, value))
      return true;

    // Delay if this is not a function type.
    if (!unwrapped.isFunctionType())
      return false;

    // Diagnose regparm with fastcall.
    const FunctionType *fn = unwrapped.get();
    CallingConv CC = fn->getCallConv();
    if (CC == CC_X86FastCall) {
      S.Diag(attr.getLoc(), diag::err_attributes_are_not_compatible)
        << FunctionType::getNameForCallConv(CC)
        << "regparm";
      attr.setInvalid();
      return true;
    }

    FunctionType::ExtInfo EI =
      unwrapped.get()->getExtInfo().withRegParm(value);
    type = unwrapped.wrap(S, S.Context.adjustFunctionType(unwrapped.get(), EI));
    return true;
  }

  // Otherwise, a calling convention.
  CallingConv CC;
  if (S.CheckCallingConvAttr(attr, CC))
    return true;

  // Delay if the type didn't work out to a function.
  if (!unwrapped.isFunctionType()) return false;

  const FunctionType *fn = unwrapped.get();
  CallingConv CCOld = fn->getCallConv();
  if (S.Context.getCanonicalCallConv(CC) ==
      S.Context.getCanonicalCallConv(CCOld)) {
    FunctionType::ExtInfo EI= unwrapped.get()->getExtInfo().withCallingConv(CC);
    type = unwrapped.wrap(S, S.Context.adjustFunctionType(unwrapped.get(), EI));
    return true;
  }

  if (CCOld != (S.LangOpts.MRTD ? CC_X86StdCall : CC_Default)) {
    // Should we diagnose reapplications of the same convention?
    S.Diag(attr.getLoc(), diag::err_attributes_are_not_compatible)
      << FunctionType::getNameForCallConv(CC)
      << FunctionType::getNameForCallConv(CCOld);
    attr.setInvalid();
    return true;
  }

  // Diagnose the use of X86 fastcall on varargs or unprototyped functions.
  if (CC == CC_X86FastCall) {
    if (isa<FunctionNoProtoType>(fn)) {
      S.Diag(attr.getLoc(), diag::err_cconv_knr)
        << FunctionType::getNameForCallConv(CC);
      attr.setInvalid();
      return true;
    }

    const FunctionProtoType *FnP = cast<FunctionProtoType>(fn);
    if (FnP->isVariadic()) {
      S.Diag(attr.getLoc(), diag::err_cconv_varargs)
        << FunctionType::getNameForCallConv(CC);
      attr.setInvalid();
      return true;
    }

    // Also diagnose fastcall with regparm.
    if (fn->getHasRegParm()) {
      S.Diag(attr.getLoc(), diag::err_attributes_are_not_compatible)
        << "regparm"
        << FunctionType::getNameForCallConv(CC);
      attr.setInvalid();
      return true;
    }
  }

  FunctionType::ExtInfo EI = unwrapped.get()->getExtInfo().withCallingConv(CC);
  type = unwrapped.wrap(S, S.Context.adjustFunctionType(unwrapped.get(), EI));
  return true;
}

/// Handle OpenCL image access qualifiers: read_only, write_only, read_write
static void HandleOpenCLImageAccessAttribute(QualType& CurType,
                                             const AttributeList &Attr,
                                             Sema &S) {
  // Check the attribute arguments.
  if (Attr.getNumArgs() != 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
    Attr.setInvalid();
    return;
  }
  Expr *sizeExpr = static_cast<Expr *>(Attr.getArg(0));
  llvm::APSInt arg(32);
  if (sizeExpr->isTypeDependent() || sizeExpr->isValueDependent() ||
      !sizeExpr->isIntegerConstantExpr(arg, S.Context)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_not_int)
      << "opencl_image_access" << sizeExpr->getSourceRange();
    Attr.setInvalid();
    return;
  }
  unsigned iarg = static_cast<unsigned>(arg.getZExtValue());
  switch (iarg) {
  case CLIA_read_only:
  case CLIA_write_only:
  case CLIA_read_write:
    // Implemented in a separate patch
    break;
  default:
    // Implemented in a separate patch
    S.Diag(Attr.getLoc(), diag::err_attribute_invalid_size)
      << sizeExpr->getSourceRange();
    Attr.setInvalid();
    break;
  }
}

/// HandleVectorSizeAttribute - this attribute is only applicable to integral
/// and float scalars, although arrays, pointers, and function return values are
/// allowed in conjunction with this construct. Aggregates with this attribute
/// are invalid, even if they are of the same size as a corresponding scalar.
/// The raw attribute should contain precisely 1 argument, the vector size for
/// the variable, measured in bytes. If curType and rawAttr are well formed,
/// this routine will return a new vector type.
static void HandleVectorSizeAttr(QualType& CurType, const AttributeList &Attr,
                                 Sema &S) {
  // Check the attribute arguments.
  if (Attr.getNumArgs() != 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
    Attr.setInvalid();
    return;
  }
  Expr *sizeExpr = static_cast<Expr *>(Attr.getArg(0));
  llvm::APSInt vecSize(32);
  if (sizeExpr->isTypeDependent() || sizeExpr->isValueDependent() ||
      !sizeExpr->isIntegerConstantExpr(vecSize, S.Context)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_not_int)
      << "vector_size" << sizeExpr->getSourceRange();
    Attr.setInvalid();
    return;
  }
  // the base type must be integer or float, and can't already be a vector.
  if (!CurType->isIntegerType() && !CurType->isRealFloatingType()) {
    S.Diag(Attr.getLoc(), diag::err_attribute_invalid_vector_type) << CurType;
    Attr.setInvalid();
    return;
  }
  unsigned typeSize = static_cast<unsigned>(S.Context.getTypeSize(CurType));
  // vecSize is specified in bytes - convert to bits.
  unsigned vectorSize = static_cast<unsigned>(vecSize.getZExtValue() * 8);

  // the vector size needs to be an integral multiple of the type size.
  if (vectorSize % typeSize) {
    S.Diag(Attr.getLoc(), diag::err_attribute_invalid_size)
      << sizeExpr->getSourceRange();
    Attr.setInvalid();
    return;
  }
  if (vectorSize == 0) {
    S.Diag(Attr.getLoc(), diag::err_attribute_zero_size)
      << sizeExpr->getSourceRange();
    Attr.setInvalid();
    return;
  }

  // Success! Instantiate the vector type, the number of elements is > 0, and
  // not required to be a power of 2, unlike GCC.
  CurType = S.Context.getVectorType(CurType, vectorSize/typeSize,
                                    VectorType::GenericVector);
}

/// \brief Process the OpenCL-like ext_vector_type attribute when it occurs on
/// a type.
static void HandleExtVectorTypeAttr(QualType &CurType,
                                    const AttributeList &Attr,
                                    Sema &S) {
  Expr *sizeExpr;

  // Special case where the argument is a template id.
  if (Attr.getParameterName()) {
    CXXScopeSpec SS;
    SourceLocation TemplateKWLoc;
    UnqualifiedId id;
    id.setIdentifier(Attr.getParameterName(), Attr.getLoc());

    ExprResult Size = S.ActOnIdExpression(S.getCurScope(), SS, TemplateKWLoc,
                                          id, false, false);
    if (Size.isInvalid())
      return;

    sizeExpr = Size.get();
  } else {
    // check the attribute arguments.
    if (Attr.getNumArgs() != 1) {
      S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
      return;
    }
    sizeExpr = Attr.getArg(0);
  }

  // Create the vector type.
  QualType T = S.BuildExtVectorType(CurType, sizeExpr, Attr.getLoc());
  if (!T.isNull())
    CurType = T;
}

/// HandleNeonVectorTypeAttr - The "neon_vector_type" and
/// "neon_polyvector_type" attributes are used to create vector types that
/// are mangled according to ARM's ABI.  Otherwise, these types are identical
/// to those created with the "vector_size" attribute.  Unlike "vector_size"
/// the argument to these Neon attributes is the number of vector elements,
/// not the vector size in bytes.  The vector width and element type must
/// match one of the standard Neon vector types.
static void HandleNeonVectorTypeAttr(QualType& CurType,
                                     const AttributeList &Attr, Sema &S,
                                     VectorType::VectorKind VecKind,
                                     const char *AttrName) {
  // Check the attribute arguments.
  if (Attr.getNumArgs() != 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
    Attr.setInvalid();
    return;
  }
  // The number of elements must be an ICE.
  Expr *numEltsExpr = static_cast<Expr *>(Attr.getArg(0));
  llvm::APSInt numEltsInt(32);
  if (numEltsExpr->isTypeDependent() || numEltsExpr->isValueDependent() ||
      !numEltsExpr->isIntegerConstantExpr(numEltsInt, S.Context)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_not_int)
      << AttrName << numEltsExpr->getSourceRange();
    Attr.setInvalid();
    return;
  }
  // Only certain element types are supported for Neon vectors.
  const BuiltinType* BTy = CurType->getAs<BuiltinType>();
  if (!BTy ||
      (VecKind == VectorType::NeonPolyVector &&
       BTy->getKind() != BuiltinType::SChar &&
       BTy->getKind() != BuiltinType::Short) ||
      (BTy->getKind() != BuiltinType::SChar &&
       BTy->getKind() != BuiltinType::UChar &&
       BTy->getKind() != BuiltinType::Short &&
       BTy->getKind() != BuiltinType::UShort &&
       BTy->getKind() != BuiltinType::Int &&
       BTy->getKind() != BuiltinType::UInt &&
       BTy->getKind() != BuiltinType::LongLong &&
       BTy->getKind() != BuiltinType::ULongLong &&
       BTy->getKind() != BuiltinType::Float)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_invalid_vector_type) <<CurType;
    Attr.setInvalid();
    return;
  }
  // The total size of the vector must be 64 or 128 bits.
  unsigned typeSize = static_cast<unsigned>(S.Context.getTypeSize(CurType));
  unsigned numElts = static_cast<unsigned>(numEltsInt.getZExtValue());
  unsigned vecSize = typeSize * numElts;
  if (vecSize != 64 && vecSize != 128) {
    S.Diag(Attr.getLoc(), diag::err_attribute_bad_neon_vector_size) << CurType;
    Attr.setInvalid();
    return;
  }

  CurType = S.Context.getVectorType(CurType, numElts, VecKind);
}

static void processTypeAttrs(TypeProcessingState &state, QualType &type,
                             bool isDeclSpec, AttributeList *attrs) {
  // Scan through and apply attributes to this type where it makes sense.  Some
  // attributes (such as __address_space__, __vector_size__, etc) apply to the
  // type, but others can be present in the type specifiers even though they
  // apply to the decl.  Here we apply type attributes and ignore the rest.

  AttributeList *next;
  do {
    AttributeList &attr = *attrs;
    next = attr.getNext();

    // Skip attributes that were marked to be invalid.
    if (attr.isInvalid())
      continue;

    // If this is an attribute we can handle, do so now,
    // otherwise, add it to the FnAttrs list for rechaining.
    switch (attr.getKind()) {
    default: break;

    case AttributeList::AT_MayAlias:
      // FIXME: This attribute needs to actually be handled, but if we ignore
      // it it breaks large amounts of Linux software.
      attr.setUsedAsTypeAttr();
      break;
    case AttributeList::AT_AddressSpace:
      HandleAddressSpaceTypeAttribute(type, attr, state.getSema());
      attr.setUsedAsTypeAttr();
      break;
    OBJC_POINTER_TYPE_ATTRS_CASELIST:
      if (!handleObjCPointerTypeAttr(state, attr, type))
        distributeObjCPointerTypeAttr(state, attr, type);
      attr.setUsedAsTypeAttr();
      break;
    case AttributeList::AT_VectorSize:
      HandleVectorSizeAttr(type, attr, state.getSema());
      attr.setUsedAsTypeAttr();
      break;
    case AttributeList::AT_ExtVectorType:
      if (state.getDeclarator().getDeclSpec().getStorageClassSpec()
            != DeclSpec::SCS_typedef)
        HandleExtVectorTypeAttr(type, attr, state.getSema());
      attr.setUsedAsTypeAttr();
      break;
    case AttributeList::AT_NeonVectorType:
      HandleNeonVectorTypeAttr(type, attr, state.getSema(),
                               VectorType::NeonVector, "neon_vector_type");
      attr.setUsedAsTypeAttr();
      break;
    case AttributeList::AT_NeonPolyVectorType:
      HandleNeonVectorTypeAttr(type, attr, state.getSema(),
                               VectorType::NeonPolyVector,
                               "neon_polyvector_type");
      attr.setUsedAsTypeAttr();
      break;
    case AttributeList::AT_OpenCLImageAccess:
      HandleOpenCLImageAccessAttribute(type, attr, state.getSema());
      attr.setUsedAsTypeAttr();
      break;

    case AttributeList::AT_Win64:
    case AttributeList::AT_Ptr32:
    case AttributeList::AT_Ptr64:
      // FIXME: don't ignore these
      attr.setUsedAsTypeAttr();
      break;

    case AttributeList::AT_NSReturnsRetained:
      if (!state.getSema().getLangOpts().ObjCAutoRefCount)
    break;
      // fallthrough into the function attrs

    FUNCTION_TYPE_ATTRS_CASELIST:
      attr.setUsedAsTypeAttr();

      // Never process function type attributes as part of the
      // declaration-specifiers.
      if (isDeclSpec)
        distributeFunctionTypeAttrFromDeclSpec(state, attr, type);

      // Otherwise, handle the possible delays.
      else if (!handleFunctionTypeAttr(state, attr, type))
        distributeFunctionTypeAttr(state, attr, type);
      break;
    }
  } while ((attrs = next));
}

/// \brief Ensure that the type of the given expression is complete.
///
/// This routine checks whether the expression \p E has a complete type. If the
/// expression refers to an instantiable construct, that instantiation is
/// performed as needed to complete its type. Furthermore
/// Sema::RequireCompleteType is called for the expression's type (or in the
/// case of a reference type, the referred-to type).
///
/// \param E The expression whose type is required to be complete.
/// \param Diagnoser The object that will emit a diagnostic if the type is
/// incomplete.
///
/// \returns \c true if the type of \p E is incomplete and diagnosed, \c false
/// otherwise.
bool Sema::RequireCompleteExprType(Expr *E, TypeDiagnoser &Diagnoser){
  QualType T = E->getType();

  // Fast path the case where the type is already complete.
  if (!T->isIncompleteType())
    return false;

  // Incomplete array types may be completed by the initializer attached to
  // their definitions. For static data members of class templates we need to
  // instantiate the definition to get this initializer and complete the type.
  if (T->isIncompleteArrayType()) {
    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParens())) {
      if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl())) {
        if (Var->isStaticDataMember() &&
            Var->getInstantiatedFromStaticDataMember()) {

          MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo();
          assert(MSInfo && "Missing member specialization information?");
          if (MSInfo->getTemplateSpecializationKind()
                != TSK_ExplicitSpecialization) {
            // If we don't already have a point of instantiation, this is it.
            if (MSInfo->getPointOfInstantiation().isInvalid()) {
              MSInfo->setPointOfInstantiation(E->getLocStart());

              // This is a modification of an existing AST node. Notify
              // listeners.
              if (ASTMutationListener *L = getASTMutationListener())
                L->StaticDataMemberInstantiated(Var);
            }

            InstantiateStaticDataMemberDefinition(E->getExprLoc(), Var);

            // Update the type to the newly instantiated definition's type both
            // here and within the expression.
            if (VarDecl *Def = Var->getDefinition()) {
              DRE->setDecl(Def);
              T = Def->getType();
              DRE->setType(T);
              E->setType(T);
            }
          }

          // We still go on to try to complete the type independently, as it
          // may also require instantiations or diagnostics if it remains
          // incomplete.
        }
      }
    }
  }

  // FIXME: Are there other cases which require instantiating something other
  // than the type to complete the type of an expression?

  // Look through reference types and complete the referred type.
  if (const ReferenceType *Ref = T->getAs<ReferenceType>())
    T = Ref->getPointeeType();

  return RequireCompleteType(E->getExprLoc(), T, Diagnoser);
}

namespace {
  struct TypeDiagnoserDiag : Sema::TypeDiagnoser {
    unsigned DiagID;

    TypeDiagnoserDiag(unsigned DiagID)
      : Sema::TypeDiagnoser(DiagID == 0), DiagID(DiagID) {}

    virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) {
      if (Suppressed) return;
      S.Diag(Loc, DiagID) << T;
    }
  };
}

bool Sema::RequireCompleteExprType(Expr *E, unsigned DiagID) {
  TypeDiagnoserDiag Diagnoser(DiagID);
  return RequireCompleteExprType(E, Diagnoser);
}

/// @brief Ensure that the type T is a complete type.
///
/// This routine checks whether the type @p T is complete in any
/// context where a complete type is required. If @p T is a complete
/// type, returns false. If @p T is a class template specialization,
/// this routine then attempts to perform class template
/// instantiation. If instantiation fails, or if @p T is incomplete
/// and cannot be completed, issues the diagnostic @p diag (giving it
/// the type @p T) and returns true.
///
/// @param Loc  The location in the source that the incomplete type
/// diagnostic should refer to.
///
/// @param T  The type that this routine is examining for completeness.
///
/// @returns @c true if @p T is incomplete and a diagnostic was emitted,
/// @c false otherwise.
bool Sema::RequireCompleteType(SourceLocation Loc, QualType T,
                               TypeDiagnoser &Diagnoser) {
  // FIXME: Add this assertion to make sure we always get instantiation points.
  //  assert(!Loc.isInvalid() && "Invalid location in RequireCompleteType");
  // FIXME: Add this assertion to help us flush out problems with
  // checking for dependent types and type-dependent expressions.
  //
  //  assert(!T->isDependentType() &&
  //         "Can't ask whether a dependent type is complete");

  // If we have a complete type, we're done.
  NamedDecl *Def = 0;
  if (!T->isIncompleteType(&Def)) {
    // If we know about the definition but it is not visible, complain.
    if (!Diagnoser.Suppressed && Def && !LookupResult::isVisible(Def)) {
      // Suppress this error outside of a SFINAE context if we've already
      // emitted the error once for this type. There's no usefulness in
      // repeating the diagnostic.
      // FIXME: Add a Fix-It that imports the corresponding module or includes
      // the header.
      if (isSFINAEContext() || HiddenDefinitions.insert(Def)) {
        Diag(Loc, diag::err_module_private_definition) << T;
        Diag(Def->getLocation(), diag::note_previous_definition);
      }
    }

    return false;
  }

  const TagType *Tag = T->getAs<TagType>();
  const ObjCInterfaceType *IFace = 0;

  if (Tag) {
    // Avoid diagnosing invalid decls as incomplete.
    if (Tag->getDecl()->isInvalidDecl())
      return true;

    // Give the external AST source a chance to complete the type.
    if (Tag->getDecl()->hasExternalLexicalStorage()) {
      Context.getExternalSource()->CompleteType(Tag->getDecl());
      if (!Tag->isIncompleteType())
        return false;
    }
  }
  else if ((IFace = T->getAs<ObjCInterfaceType>())) {
    // Avoid diagnosing invalid decls as incomplete.
    if (IFace->getDecl()->isInvalidDecl())
      return true;

    // Give the external AST source a chance to complete the type.
    if (IFace->getDecl()->hasExternalLexicalStorage()) {
      Context.getExternalSource()->CompleteType(IFace->getDecl());
      if (!IFace->isIncompleteType())
        return false;
    }
  }

  // If we have a class template specialization or a class member of a
  // class template specialization, or an array with known size of such,
  // try to instantiate it.
  QualType MaybeTemplate = T;
  while (const ConstantArrayType *Array
           = Context.getAsConstantArrayType(MaybeTemplate))
    MaybeTemplate = Array->getElementType();
  if (const RecordType *Record = MaybeTemplate->getAs<RecordType>()) {
    if (ClassTemplateSpecializationDecl *ClassTemplateSpec
          = dyn_cast<ClassTemplateSpecializationDecl>(Record->getDecl())) {
      if (ClassTemplateSpec->getSpecializationKind() == TSK_Undeclared)
        return InstantiateClassTemplateSpecialization(Loc, ClassTemplateSpec,
                                                      TSK_ImplicitInstantiation,
                                            /*Complain=*/!Diagnoser.Suppressed);
    } else if (CXXRecordDecl *Rec
                 = dyn_cast<CXXRecordDecl>(Record->getDecl())) {
      CXXRecordDecl *Pattern = Rec->getInstantiatedFromMemberClass();
      if (!Rec->isBeingDefined() && Pattern) {
        MemberSpecializationInfo *MSI = Rec->getMemberSpecializationInfo();
        assert(MSI && "Missing member specialization information?");
        // This record was instantiated from a class within a template.
        if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization)
          return InstantiateClass(Loc, Rec, Pattern,
                                  getTemplateInstantiationArgs(Rec),
                                  TSK_ImplicitInstantiation,
                                  /*Complain=*/!Diagnoser.Suppressed);
      }
    }
  }

  if (Diagnoser.Suppressed)
    return true;

  // We have an incomplete type. Produce a diagnostic.
  Diagnoser.diagnose(*this, Loc, T);

  // If the type was a forward declaration of a class/struct/union
  // type, produce a note.
  if (Tag && !Tag->getDecl()->isInvalidDecl())
    Diag(Tag->getDecl()->getLocation(),
         Tag->isBeingDefined() ? diag::note_type_being_defined
                               : diag::note_forward_declaration)
      << QualType(Tag, 0);

  // If the Objective-C class was a forward declaration, produce a note.
  if (IFace && !IFace->getDecl()->isInvalidDecl())
    Diag(IFace->getDecl()->getLocation(), diag::note_forward_class);

  return true;
}

bool Sema::RequireCompleteType(SourceLocation Loc, QualType T,
                               unsigned DiagID) {
  TypeDiagnoserDiag Diagnoser(DiagID);
  return RequireCompleteType(Loc, T, Diagnoser);
}

/// @brief Ensure that the type T is a literal type.
///
/// This routine checks whether the type @p T is a literal type. If @p T is an
/// incomplete type, an attempt is made to complete it. If @p T is a literal
/// type, or @p AllowIncompleteType is true and @p T is an incomplete type,
/// returns false. Otherwise, this routine issues the diagnostic @p PD (giving
/// it the type @p T), along with notes explaining why the type is not a
/// literal type, and returns true.
///
/// @param Loc  The location in the source that the non-literal type
/// diagnostic should refer to.
///
/// @param T  The type that this routine is examining for literalness.
///
/// @param Diagnoser Emits a diagnostic if T is not a literal type.
///
/// @returns @c true if @p T is not a literal type and a diagnostic was emitted,
/// @c false otherwise.
bool Sema::RequireLiteralType(SourceLocation Loc, QualType T,
                              TypeDiagnoser &Diagnoser) {
  assert(!T->isDependentType() && "type should not be dependent");

  QualType ElemType = Context.getBaseElementType(T);
  RequireCompleteType(Loc, ElemType, 0);

  if (T->isLiteralType())
    return false;

  if (Diagnoser.Suppressed)
    return true;

  Diagnoser.diagnose(*this, Loc, T);

  if (T->isVariableArrayType())
    return true;

  const RecordType *RT = ElemType->getAs<RecordType>();
  if (!RT)
    return true;

  const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());

  // A partially-defined class type can't be a literal type, because a literal
  // class type must have a trivial destructor (which can't be checked until
  // the class definition is complete).
  if (!RD->isCompleteDefinition()) {
    RequireCompleteType(Loc, ElemType, diag::note_non_literal_incomplete, T);
    return true;
  }

  // If the class has virtual base classes, then it's not an aggregate, and
  // cannot have any constexpr constructors or a trivial default constructor,
  // so is non-literal. This is better to diagnose than the resulting absence
  // of constexpr constructors.
  if (RD->getNumVBases()) {
    Diag(RD->getLocation(), diag::note_non_literal_virtual_base)
      << RD->isStruct() << RD->getNumVBases();
    for (CXXRecordDecl::base_class_const_iterator I = RD->vbases_begin(),
           E = RD->vbases_end(); I != E; ++I)
      Diag(I->getLocStart(),
           diag::note_constexpr_virtual_base_here) << I->getSourceRange();
  } else if (!RD->isAggregate() && !RD->hasConstexprNonCopyMoveConstructor() &&
             !RD->hasTrivialDefaultConstructor()) {
    Diag(RD->getLocation(), diag::note_non_literal_no_constexpr_ctors) << RD;
  } else if (RD->hasNonLiteralTypeFieldsOrBases()) {
    for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
         E = RD->bases_end(); I != E; ++I) {
      if (!I->getType()->isLiteralType()) {
        Diag(I->getLocStart(),
             diag::note_non_literal_base_class)
          << RD << I->getType() << I->getSourceRange();
        return true;
      }
    }
    for (CXXRecordDecl::field_iterator I = RD->field_begin(),
         E = RD->field_end(); I != E; ++I) {
      if (!I->getType()->isLiteralType() ||
          I->getType().isVolatileQualified()) {
        Diag(I->getLocation(), diag::note_non_literal_field)
          << RD << *I << I->getType()
          << I->getType().isVolatileQualified();
        return true;
      }
    }
  } else if (!RD->hasTrivialDestructor()) {
    // All fields and bases are of literal types, so have trivial destructors.
    // If this class's destructor is non-trivial it must be user-declared.
    CXXDestructorDecl *Dtor = RD->getDestructor();
    assert(Dtor && "class has literal fields and bases but no dtor?");
    if (!Dtor)
      return true;

    Diag(Dtor->getLocation(), Dtor->isUserProvided() ?
         diag::note_non_literal_user_provided_dtor :
         diag::note_non_literal_nontrivial_dtor) << RD;
  }

  return true;
}

bool Sema::RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID) {
  TypeDiagnoserDiag Diagnoser(DiagID);
  return RequireLiteralType(Loc, T, Diagnoser);
}

/// \brief Retrieve a version of the type 'T' that is elaborated by Keyword
/// and qualified by the nested-name-specifier contained in SS.
QualType Sema::getElaboratedType(ElaboratedTypeKeyword Keyword,
                                 const CXXScopeSpec &SS, QualType T) {
  if (T.isNull())
    return T;
  NestedNameSpecifier *NNS;
  if (SS.isValid())
    NNS = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
  else {
    if (Keyword == ETK_None)
      return T;
    NNS = 0;
  }
  return Context.getElaboratedType(Keyword, NNS, T);
}

QualType Sema::BuildTypeofExprType(Expr *E, SourceLocation Loc) {
  ExprResult ER = CheckPlaceholderExpr(E);
  if (ER.isInvalid()) return QualType();
  E = ER.take();

  if (!E->isTypeDependent()) {
    QualType T = E->getType();
    if (const TagType *TT = T->getAs<TagType>())
      DiagnoseUseOfDecl(TT->getDecl(), E->getExprLoc());
  }
  return Context.getTypeOfExprType(E);
}

/// getDecltypeForExpr - Given an expr, will return the decltype for
/// that expression, according to the rules in C++11
/// [dcl.type.simple]p4 and C++11 [expr.lambda.prim]p18.
static QualType getDecltypeForExpr(Sema &S, Expr *E) {
  if (E->isTypeDependent())
    return S.Context.DependentTy;

  // C++11 [dcl.type.simple]p4:
  //   The type denoted by decltype(e) is defined as follows:
  //
  //     - if e is an unparenthesized id-expression or an unparenthesized class
  //       member access (5.2.5), decltype(e) is the type of the entity named
  //       by e. If there is no such entity, or if e names a set of overloaded
  //       functions, the program is ill-formed;
  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
    if (const ValueDecl *VD = dyn_cast<ValueDecl>(DRE->getDecl()))
      return VD->getType();
  }
  if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
    if (const FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
      return FD->getType();
  }

  // C++11 [expr.lambda.prim]p18:
  //   Every occurrence of decltype((x)) where x is a possibly
  //   parenthesized id-expression that names an entity of automatic
  //   storage duration is treated as if x were transformed into an
  //   access to a corresponding data member of the closure type that
  //   would have been declared if x were an odr-use of the denoted
  //   entity.
  using namespace sema;
  if (S.getCurLambda()) {
    if (isa<ParenExpr>(E)) {
      if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParens())) {
        if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl())) {
          QualType T = S.getCapturedDeclRefType(Var, DRE->getLocation());
          if (!T.isNull())
            return S.Context.getLValueReferenceType(T);
        }
      }
    }
  }


  // C++11 [dcl.type.simple]p4:
  //   [...]
  QualType T = E->getType();
  switch (E->getValueKind()) {
  //     - otherwise, if e is an xvalue, decltype(e) is T&&, where T is the
  //       type of e;
  case VK_XValue: T = S.Context.getRValueReferenceType(T); break;
  //     - otherwise, if e is an lvalue, decltype(e) is T&, where T is the
  //       type of e;
  case VK_LValue: T = S.Context.getLValueReferenceType(T); break;
  //  - otherwise, decltype(e) is the type of e.
  case VK_RValue: break;
  }

  return T;
}

QualType Sema::BuildDecltypeType(Expr *E, SourceLocation Loc) {
  ExprResult ER = CheckPlaceholderExpr(E);
  if (ER.isInvalid()) return QualType();
  E = ER.take();

  return Context.getDecltypeType(E, getDecltypeForExpr(*this, E));
}

QualType Sema::BuildUnaryTransformType(QualType BaseType,
                                       UnaryTransformType::UTTKind UKind,
                                       SourceLocation Loc) {
  switch (UKind) {
  case UnaryTransformType::EnumUnderlyingType:
    if (!BaseType->isDependentType() && !BaseType->isEnumeralType()) {
      Diag(Loc, diag::err_only_enums_have_underlying_types);
      return QualType();
    } else {
      QualType Underlying = BaseType;
      if (!BaseType->isDependentType()) {
        EnumDecl *ED = BaseType->getAs<EnumType>()->getDecl();
        assert(ED && "EnumType has no EnumDecl");
        DiagnoseUseOfDecl(ED, Loc);
        Underlying = ED->getIntegerType();
      }
      assert(!Underlying.isNull());
      return Context.getUnaryTransformType(BaseType, Underlying,
                                        UnaryTransformType::EnumUnderlyingType);
    }
  }
  llvm_unreachable("unknown unary transform type");
}

QualType Sema::BuildAtomicType(QualType T, SourceLocation Loc) {
  if (!T->isDependentType()) {
    // FIXME: It isn't entirely clear whether incomplete atomic types
    // are allowed or not; for simplicity, ban them for the moment.
    if (RequireCompleteType(Loc, T, diag::err_atomic_specifier_bad_type, 0))
      return QualType();

    int DisallowedKind = -1;
    if (T->isArrayType())
      DisallowedKind = 1;
    else if (T->isFunctionType())
      DisallowedKind = 2;
    else if (T->isReferenceType())
      DisallowedKind = 3;
    else if (T->isAtomicType())
      DisallowedKind = 4;
    else if (T.hasQualifiers())
      DisallowedKind = 5;
    else if (!T.isTriviallyCopyableType(Context))
      // Some other non-trivially-copyable type (probably a C++ class)
      DisallowedKind = 6;

    if (DisallowedKind != -1) {
      Diag(Loc, diag::err_atomic_specifier_bad_type) << DisallowedKind << T;
      return QualType();
    }

    // FIXME: Do we need any handling for ARC here?
  }

  // Build the pointer type.
  return Context.getAtomicType(T);
}