lib/Sema/SemaType.cpp

//===--- 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/SemaInternal.h"
#include "TypeLocBuilder.h"
#include "clang/AST/ASTConsumer.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/Expr.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/TypeLocVisitor.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 "clang/Sema/ScopeInfo.h"
#include "clang/Sema/Template.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/ErrorHandling.h"

using namespace clang;

enum TypeDiagSelector {
  TDS_Function,
  TDS_Pointer,
  TDS_ObjCObjOrBlock
};

/// 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) {
  TypeDiagSelector WhichType;
  bool useExpansionLoc = true;
  switch (attr.getKind()) {
  case AttributeList::AT_ObjCGC:        WhichType = TDS_Pointer; break;
  case AttributeList::AT_ObjCOwnership: WhichType = TDS_ObjCObjOrBlock; break;
  default:
    // Assume everything else was a function attribute.
    WhichType = TDS_Function;
    useExpansionLoc = false;
    break;
  }

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

  // The GC attributes are usually written with macros;  special-case them.
  IdentifierInfo *II = attr.isArgIdent(0) ? attr.getArgAsIdent(0)->Ident : 0;
  if (useExpansionLoc && loc.isMacroID() && II) {
    if (II->isStr("strong")) {
      if (S.findMacroSpelling(loc, "__strong")) name = "__strong";
    } else if (II->isStr("weak")) {
      if (S.findMacroSpelling(loc, "__weak")) name = "__weak";
    }
  }

  S.Diag(loc, diag::warn_type_attribute_wrong_type) << name << WhichType
    << 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_MSABI: \
    case AttributeList::AT_SysVABI: \
    case AttributeList::AT_Regparm: \
    case AttributeList::AT_Pcs: \
    case AttributeList::AT_PnaclCall: \
    case AttributeList::AT_IntelOclBicc

// Microsoft-specific type qualifiers.
#define MS_TYPE_ATTRS_CASELIST  \
    case AttributeList::AT_Ptr32: \
    case AttributeList::AT_Ptr64: \
    case AttributeList::AT_SPtr: \
    case AttributeList::AT_UPtr

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;
    }

    bool isProcessingDeclSpec() const {
      return chunkIndex == declarator.getNumTypeObjects();
    }

    unsigned getCurrentChunkIndex() const {
      return chunkIndex;
    }

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

    AttributeList *&getCurrentAttrListRef() const {
      if (isProcessingDeclSpec())
        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);
    }
  };
}

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);
}

/// The location of a type attribute.
enum TypeAttrLocation {
  /// The attribute is in the decl-specifier-seq.
  TAL_DeclSpec,
  /// The attribute is part of a DeclaratorChunk.
  TAL_DeclChunk,
  /// The attribute is immediately after the declaration's name.
  TAL_DeclName
};

static void processTypeAttrs(TypeProcessingState &state,
                             QualType &type, TypeAttrLocation TAL,
                             AttributeList *attrs);

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

static bool handleMSPointerTypeQualifierAttr(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 the index of a declarator chunk, check whether that chunk
/// directly specifies the return type of a function and, if so, find
/// an appropriate place for it.
///
/// \param i - a notional index which the search will start
///   immediately inside
static DeclaratorChunk *maybeMovePastReturnType(Declarator &declarator,
                                                unsigned i) {
  assert(i <= declarator.getNumTypeObjects());

  DeclaratorChunk *result = 0;

  // First, look inwards past parens for a function declarator.
  for (; i != 0; --i) {
    DeclaratorChunk &fnChunk = declarator.getTypeObject(i-1);
    switch (fnChunk.Kind) {
    case DeclaratorChunk::Paren:
      continue;

    // If we find anything except a function, bail out.
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Array:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::MemberPointer:
      return result;

    // If we do find a function declarator, scan inwards from that,
    // looking for a block-pointer declarator.
    case DeclaratorChunk::Function:
      for (--i; i != 0; --i) {
        DeclaratorChunk &blockChunk = declarator.getTypeObject(i-1);
        switch (blockChunk.Kind) {
        case DeclaratorChunk::Paren:
        case DeclaratorChunk::Pointer:
        case DeclaratorChunk::Array:
        case DeclaratorChunk::Function:
        case DeclaratorChunk::Reference:
        case DeclaratorChunk::MemberPointer:
          continue;
        case DeclaratorChunk::BlockPointer:
          result = &blockChunk;
          goto continue_outer;
        }
        llvm_unreachable("bad declarator chunk kind");
      }

      // If we run out of declarators doing that, we're done.
      return result;
    }
    llvm_unreachable("bad declarator chunk kind");

    // Okay, reconsider from our new point.
  continue_outer: ;
  }

  // Ran out of chunks, bail out.
  return result;
}

/// 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();

  // Move it to the outermost normal or block pointer declarator.
  for (unsigned i = state.getCurrentChunkIndex(); i != 0; --i) {
    DeclaratorChunk &chunk = declarator.getTypeObject(i-1);
    switch (chunk.Kind) {
    case DeclaratorChunk::Pointer:
    case DeclaratorChunk::BlockPointer: {
      // But don't move an ARC ownership attribute to the return type
      // of a block.
      DeclaratorChunk *destChunk = 0;
      if (state.isProcessingDeclSpec() &&
          attr.getKind() == AttributeList::AT_ObjCOwnership)
        destChunk = maybeMovePastReturnType(declarator, i - 1);
      if (!destChunk) destChunk = &chunk;

      moveAttrFromListToList(attr, state.getCurrentAttrListRef(),
                             destChunk->getAttrListRef());
      return;
    }

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

    // We may be starting at the return type of a block.
    case DeclaratorChunk::Function:
      if (state.isProcessingDeclSpec() &&
          attr.getKind() == AttributeList::AT_ObjCOwnership) {
        if (DeclaratorChunk *dest = maybeMovePastReturnType(declarator, i)) {
          moveAttrFromListToList(attr, state.getCurrentAttrListRef(),
                                 dest->getAttrListRef());
          return;
        }
      }
      goto error;

    // Don't walk through these.
    case DeclaratorChunk::Reference:
    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;
  }

  return handleFunctionTypeAttr(state, attr, declSpecType);
}

/// 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();

  // C++11 attributes before the decl specifiers actually appertain to
  // the declarators. Move them straight there. We don't support the
  // 'put them wherever you like' semantics we allow for GNU attributes.
  if (attr.isCXX11Attribute()) {
    moveAttrFromListToList(attr, state.getCurrentAttrListRef(),
                           state.getDeclarator().getAttrListRef());
    return;
  }

  // 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();

    // Do not distribute C++11 attributes. They have strict rules for what
    // they appertain to.
    if (attr->isCXX11Attribute())
      continue;

    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;

    MS_TYPE_ATTRS_CASELIST:
      // Microsoft type attributes cannot go after the declarator-id.
      continue;

    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.
  SourceLocation NoLoc;
  declarator.AddInnermostTypeInfo(DeclaratorChunk::getFunction(
                             /*HasProto=*/true,
                             /*IsAmbiguous=*/false,
                             /*LParenLoc=*/NoLoc,
                             /*ArgInfo=*/0,
                             /*NumArgs=*/0,
                             /*EllipsisLoc=*/NoLoc,
                             /*RParenLoc=*/NoLoc,
                             /*TypeQuals=*/0,
                             /*RefQualifierIsLvalueRef=*/true,
                             /*RefQualifierLoc=*/NoLoc,
                             /*ConstQualifierLoc=*/NoLoc,
                             /*VolatileQualifierLoc=*/NoLoc,
                             /*MutableLoc=*/NoLoc,
                             EST_None,
                             /*ESpecLoc=*/NoLoc,
                             /*Exceptions=*/0,
                             /*ExceptionRanges=*/0,
                             /*NumExceptions=*/0,
                             /*NoexceptExpr=*/0,
                             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(),
                               Context.getPrintingPolicy());
      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(),
                               Context.getPrintingPolicy());
      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*const*)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 (S.getLangOpts().CPlusPlus1y &&
        declarator.getContext() == Declarator::LambdaExprContext) {
      // In C++1y, a lambda's implicit return type is 'auto'.
      Result = Context.getAutoDeductType();
      break;
    } else 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."
      if (S.getLangOpts().CPlusPlus) {
        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 or C++11 feature.
        if (!S.getLangOpts().C99) {
          if (S.getLangOpts().CPlusPlus)
            S.Diag(DS.getTypeSpecWidthLoc(),
                   S.getLangOpts().CPlusPlus11 ?
                   diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
          else
            S.Diag(DS.getTypeSpecWidthLoc(), diag::ext_c99_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 or C++11 feature.
        if (!S.getLangOpts().C99) {
          if (S.getLangOpts().CPlusPlus)
            S.Diag(DS.getTypeSpecWidthLoc(),
                   S.getLangOpts().CPlusPlus11 ?
                   diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
          else
            S.Diag(DS.getTypeSpecWidthLoc(), diag::ext_c99_longlong);
        }
        break;
      }
    }
    break;
  }
  case DeclSpec::TST_int128:
    if (!S.PP.getTargetInfo().hasInt128Type())
      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_int128_unsupported);
    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:
  case DeclSpec::TST_interface: {
    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*const*) PQ,
                                             DS.getNumProtocolQualifiers());
      } else if (Result->isObjCIdType()) {
        // id<protocol-list>
        Result = Context.getObjCObjectType(Context.ObjCBuiltinIdTy,
                                           (ObjCProtocolDecl*const*) PQ,
                                           DS.getNumProtocolQualifiers());
        Result = Context.getObjCObjectPointerType(Result);
      } else if (Result->isObjCClassType()) {
        // Class<protocol-list>
        Result = Context.getObjCObjectType(Context.ObjCBuiltinClassTy,
                                           (ObjCProtocolDecl*const*) 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.
    // If auto is mentioned in a lambda parameter context, convert it to a 
    // template parameter type immediately, with the appropriate depth and 
    // index, and update sema's state (LambdaScopeInfo) for the current lambda 
    // being analyzed (which tracks the invented type template parameter).
    if (declarator.getContext() == Declarator::LambdaExprParameterContext) {
      sema::LambdaScopeInfo *LSI = S.getCurLambda();
      assert(LSI && "No LambdaScopeInfo on the stack!");
      const unsigned TemplateParameterDepth = LSI->AutoTemplateParameterDepth;
      const unsigned AutoParameterPosition = LSI->AutoTemplateParams.size();
      const bool IsParameterPack = declarator.hasEllipsis();
      
      // Create a name for the invented template parameter type.
      std::string InventedTemplateParamName = "$auto-";
      llvm::raw_string_ostream ss(InventedTemplateParamName);
      ss << TemplateParameterDepth; 
      ss << "-" << AutoParameterPosition;
      ss.flush();

      IdentifierInfo& TemplateParamII = Context.Idents.get(
                                        InventedTemplateParamName.c_str());
      // Turns out we must create the TemplateTypeParmDecl here to 
      // retrieve the corresponding template parameter type. 
      TemplateTypeParmDecl *CorrespondingTemplateParam =
        TemplateTypeParmDecl::Create(Context, 
        // Temporarily add to the TranslationUnit DeclContext.  When the 
        // associated TemplateParameterList is attached to a template
        // declaration (such as FunctionTemplateDecl), the DeclContext 
        // for each template parameter gets updated appropriately via
        // a call to AdoptTemplateParameterList. 
        Context.getTranslationUnitDecl(), 
        /*KeyLoc*/ SourceLocation(), 
        /*NameLoc*/ declarator.getLocStart(),  
        TemplateParameterDepth, 
        AutoParameterPosition,  // our template param index 
        /* Identifier*/ &TemplateParamII, false, IsParameterPack);
      LSI->AutoTemplateParams.push_back(CorrespondingTemplateParam);
      // Replace the 'auto' in the function parameter with this invented 
      // template type parameter.
      Result = QualType(CorrespondingTemplateParam->getTypeForDecl(), 0);  
    } else {
      Result = Context.getAutoType(QualType(), /*decltype(auto)*/false, false);
    }
    break;

  case DeclSpec::TST_decltype_auto:
    Result = Context.getAutoType(QualType(), 
                                 /*decltype(auto)*/true, 
                                 /*IsDependent*/   false);
    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, TAL_DeclSpec, attrs);

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

    // 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) {
      if (TypeQuals & DeclSpec::TQ_const)
        S.Diag(DS.getConstSpecLoc(), diag::warn_typecheck_function_qualifiers)
          << Result << DS.getSourceRange();
      else if (TypeQuals & DeclSpec::TQ_volatile)
        S.Diag(DS.getVolatileSpecLoc(), diag::warn_typecheck_function_qualifiers)
          << Result << DS.getSourceRange();
      else {
        assert((TypeQuals & (DeclSpec::TQ_restrict | DeclSpec::TQ_atomic)) &&
               "Has CVRA quals but not C, V, R, or A?");
        // No diagnostic; we'll diagnose 'restrict' or '_Atomic' applied to a
        // function type later, in BuildQualifiedType.
      }
    }

    // C++11 [dcl.ref]p1:
    //   Cv-qualified references are ill-formed except when the
    //   cv-qualifiers are introduced through the use of a typedef-name
    //   or decltype-specifier, in which case the cv-qualifiers are ignored.
    //
    // There don't appear to be any other contexts in which a cv-qualified
    // reference type could be formed, so the 'ill-formed' clause here appears
    // to never happen.
    if (DS.getTypeSpecType() == DeclSpec::TST_typename &&
        TypeQuals && Result->isReferenceType()) {
      // If this occurs outside a template instantiation, warn the user about
      // it; they probably didn't mean to specify a redundant qualifier.
      typedef std::pair<DeclSpec::TQ, SourceLocation> QualLoc;
      QualLoc Quals[] = {
        QualLoc(DeclSpec::TQ_const, DS.getConstSpecLoc()),
        QualLoc(DeclSpec::TQ_volatile, DS.getVolatileSpecLoc()),
        QualLoc(DeclSpec::TQ_atomic, DS.getAtomicSpecLoc())
      };
      for (unsigned I = 0, N = llvm::array_lengthof(Quals); I != N; ++I) {
        if (S.ActiveTemplateInstantiations.empty()) {
          if (TypeQuals & Quals[I].first)
            S.Diag(Quals[I].second, diag::warn_typecheck_reference_qualifiers)
              << DeclSpec::getSpecifierName(Quals[I].first) << Result
              << FixItHint::CreateRemoval(Quals[I].second);
        }
        TypeQuals &= ~Quals[I].first;
      }
    }

    // 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 nor _Atomic, so it doesn't force us to
      // produce a warning in this case.
    }

    QualType Qualified = S.BuildQualifiedType(Result, DeclLoc, TypeQuals, &DS);

    // If adding qualifiers fails, just use the unqualified type.
    if (Qualified.isNull())
      declarator.setInvalidType(true);
    else
      Result = Qualified;
  }

  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, const DeclSpec *DS) {
  // 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;

    if (T->isAnyPointerType() || T->isReferenceType() ||
        T->isMemberPointerType()) {
      QualType EltTy;
      if (T->isObjCObjectPointerType())
        EltTy = T;
      else if (const MemberPointerType *PTy = T->getAs<MemberPointerType>())
        EltTy = PTy->getPointeeType();
      else
        EltTy = T->getPointeeType();

      // If we have a pointer or reference, the pointee must have an object
      // incomplete type.
      if (!EltTy->isIncompleteOrObjectType()) {
        DiagID = diag::err_typecheck_invalid_restrict_invalid_pointee;
        ProblemTy = EltTy;
      }
    } else if (!T->isDependentType()) {
      DiagID = diag::err_typecheck_invalid_restrict_not_pointer;
      ProblemTy = T;
    }

    if (DiagID) {
      Diag(DS ? DS->getRestrictSpecLoc() : Loc, DiagID) << ProblemTy;
      Qs.removeRestrict();
    }
  }

  return Context.getQualifiedType(T, Qs);
}

QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
                                  unsigned CVRA, const DeclSpec *DS) {
  // Convert from DeclSpec::TQ to Qualifiers::TQ by just dropping TQ_atomic.
  unsigned CVR = CVRA & ~DeclSpec::TQ_atomic;

  // C11 6.7.3/5:
  //   If the same qualifier appears more than once in the same
  //   specifier-qualifier-list, either directly or via one or more typedefs,
  //   the behavior is the same as if it appeared only once.
  //
  // It's not specified what happens when the _Atomic qualifier is applied to
  // a type specified with the _Atomic specifier, but we assume that this
  // should be treated as if the _Atomic qualifier appeared multiple times.
  if (CVRA & DeclSpec::TQ_atomic && !T->isAtomicType()) {
    // C11 6.7.3/5:
    //   If other qualifiers appear along with the _Atomic qualifier in a
    //   specifier-qualifier-list, the resulting type is the so-qualified
    //   atomic type.
    //
    // Don't need to worry about array types here, since _Atomic can't be
    // applied to such types.
    SplitQualType Split = T.getSplitUnqualifiedType();
    T = BuildAtomicType(QualType(Split.Ty, 0),
                        DS ? DS->getAtomicSpecLoc() : Loc);
    if (T.isNull())
      return T;
    Split.Quals.addCVRQualifiers(CVR);
    return BuildQualifiedType(T, Loc, Split.Quals);
  }

  return BuildQualifiedType(T, Loc, Qualifiers::fromCVRMask(CVR), DS);
}

/// \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) {}

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

    void diagnoseFold(Sema &S, SourceLocation Loc, SourceRange SR) override {
      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();

    // Mentioning a member pointer type for an array type causes us to lock in
    // an inheritance model, even if it's inside an unused typedef.
    if (Context.getTargetInfo().getCXXABI().isMicrosoft())
      if (const MemberPointerType *MPTy = T->getAs<MemberPointerType>())
        if (!MPTy->getClass()->isDependentType())
          RequireCompleteType(Loc, T, 0);

  } 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 (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().CPlusPlus11 &&
      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().CPlusPlus11 &&
        !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() && !T->isUndeducedType()) {
      // 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();
        return QualType();
      }
    }

    T = Context.getConstantArrayType(T, ConstVal, ASM, Quals);
  }

  // OpenCL v1.2 s6.9.d: variable length arrays are not supported.
  if (getLangOpts().OpenCL && T->isVariableArrayType()) {
    Diag(Loc, diag::err_opencl_vla);
    return QualType();
  }
  // 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() &&
          !RequireCompleteType(Loc, BaseT, 0) &&
          !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;
  }

  if (T->isVariableArrayType()) {
    // Warn about VLAs for -Wvla.
    Diag(Loc, diag::warn_vla_used);
  }

  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_type)
        << "ext_vector_type" << AANT_ArgumentIntegerConstant
        << 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();
    }

    if (VectorType::isVectorSizeTooLarge(vectorSize)) {
      Diag(AttrLoc, diag::err_attribute_size_too_large)
        << ArraySize->getSourceRange();
      return QualType();
    }

    return Context.getExtVectorType(T, vectorSize);
  }

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

bool Sema::CheckFunctionReturnType(QualType T, SourceLocation Loc) {
  if (T->isArrayType() || T->isFunctionType()) {
    Diag(Loc, diag::err_func_returning_array_function)
      << T->isFunctionType() << T;
    return true;
  }

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

  // Methods cannot return interface types. All ObjC objects are
  // passed by reference.
  if (T->isObjCObjectType()) {
    Diag(Loc, diag::err_object_cannot_be_passed_returned_by_value) << 0 << T;
    return 0;
  }

  return false;
}

QualType Sema::BuildFunctionType(QualType T,
                                 llvm::MutableArrayRef<QualType> ParamTypes,
                                 SourceLocation Loc, DeclarationName Entity,
                                 const FunctionProtoType::ExtProtoInfo &EPI) {
  bool Invalid = false;

  Invalid |= CheckFunctionReturnType(T, Loc);

  for (unsigned Idx = 0, Cnt = ParamTypes.size(); Idx < Cnt; ++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();

  return Context.getFunctionType(T, ParamTypes, 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)
      << getPrintableNameForEntity(Entity) << T;
    return QualType();
  }

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

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

  // Adjust the default free function calling convention to the default method
  // calling convention.
  if (T->isFunctionType())
    adjustMemberFunctionCC(T, /*IsStatic=*/false);

  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(
    Sema &S, unsigned Quals,
    SourceLocation FallbackLoc,
    SourceLocation ConstQualLoc = SourceLocation(),
    SourceLocation VolatileQualLoc = SourceLocation(),
    SourceLocation RestrictQualLoc = SourceLocation(),
    SourceLocation AtomicQualLoc = SourceLocation()) {
  if (!Quals)
    return;

  const SourceManager &SM = S.getSourceManager();

  struct Qual {
    unsigned Mask;
    const char *Name;
    SourceLocation Loc;
  } const QualKinds[4] = {
    { DeclSpec::TQ_const, "const", ConstQualLoc },
    { DeclSpec::TQ_volatile, "volatile", VolatileQualLoc },
    { DeclSpec::TQ_restrict, "restrict", RestrictQualLoc },
    { DeclSpec::TQ_atomic, "_Atomic", AtomicQualLoc }
  };

  SmallString<32> QualStr;
  unsigned NumQuals = 0;
  SourceLocation Loc;
  FixItHint FixIts[4];

  // Build a string naming the redundant qualifiers.
  for (unsigned I = 0; I != 4; ++I) {
    if (Quals & QualKinds[I].Mask) {
      if (!QualStr.empty()) QualStr += ' ';
      QualStr += QualKinds[I].Name;

      // If we have a location for the qualifier, offer a fixit.
      SourceLocation QualLoc = QualKinds[I].Loc;
      if (!QualLoc.isInvalid()) {
        FixIts[NumQuals] = FixItHint::CreateRemoval(QualLoc);
        if (Loc.isInvalid() || SM.isBeforeInTranslationUnit(QualLoc, Loc))
          Loc = QualLoc;
      }

      ++NumQuals;
    }
  }

  S.Diag(Loc.isInvalid() ? FallbackLoc : Loc, diag::warn_qual_return_type)
    << QualStr << NumQuals << FixIts[0] << FixIts[1] << FixIts[2] << FixIts[3];
}

// Diagnose pointless type qualifiers on the return type of a function.
static void diagnoseIgnoredFunctionQualifiers(Sema &S, QualType RetTy,
                                              Declarator &D,
                                              unsigned FunctionChunkIndex) {
  if (D.getTypeObject(FunctionChunkIndex).Fun.hasTrailingReturnType()) {
    // FIXME: TypeSourceInfo doesn't preserve location information for
    // qualifiers.
    diagnoseIgnoredQualifiers(S, RetTy.getLocalCVRQualifiers(),
                              D.getIdentifierLoc());
    return;
  }

  for (unsigned OuterChunkIndex = FunctionChunkIndex + 1,
                End = D.getNumTypeObjects();
       OuterChunkIndex != End; ++OuterChunkIndex) {
    DeclaratorChunk &OuterChunk = D.getTypeObject(OuterChunkIndex);
    switch (OuterChunk.Kind) {
    case DeclaratorChunk::Paren:
      continue;

    case DeclaratorChunk::Pointer: {
      DeclaratorChunk::PointerTypeInfo &PTI = OuterChunk.Ptr;
      diagnoseIgnoredQualifiers(
          S, PTI.TypeQuals,
          SourceLocation(),
          SourceLocation::getFromRawEncoding(PTI.ConstQualLoc),
          SourceLocation::getFromRawEncoding(PTI.VolatileQualLoc),
          SourceLocation::getFromRawEncoding(PTI.RestrictQualLoc),
          SourceLocation::getFromRawEncoding(PTI.AtomicQualLoc));
      return;
    }

    case DeclaratorChunk::Function:
    case DeclaratorChunk::BlockPointer:
    case DeclaratorChunk::Reference:
    case DeclaratorChunk::Array:
    case DeclaratorChunk::MemberPointer:
      // FIXME: We can't currently provide an accurate source location and a
      // fix-it hint for these.
      unsigned AtomicQual = RetTy->isAtomicType() ? DeclSpec::TQ_atomic : 0;
      diagnoseIgnoredQualifiers(S, RetTy.getCVRQualifiers() | AtomicQual,
                                D.getIdentifierLoc());
      return;
    }

    llvm_unreachable("unknown declarator chunk kind");
  }

  // If the qualifiers come from a conversion function type, don't diagnose
  // them -- they're not necessarily redundant, since such a conversion
  // operator can be explicitly called as "x.operator const int()".
  if (D.getName().getKind() == UnqualifiedId::IK_ConversionFunctionId)
    return;

  // Just parens all the way out to the decl specifiers. Diagnose any qualifiers
  // which are present there.
  diagnoseIgnoredQualifiers(S, D.getDeclSpec().getTypeQualifiers(),
                            D.getIdentifierLoc(),
                            D.getDeclSpec().getConstSpecLoc(),
                            D.getDeclSpec().getVolatileSpecLoc(),
                            D.getDeclSpec().getRestrictSpecLoc(),
                            D.getDeclSpec().getAtomicSpecLoc());
}

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;

  bool ContainsPlaceholderType = false;

  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);
    ContainsPlaceholderType = D.getDeclSpec().containsPlaceholderType();

    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, TAL_DeclSpec, 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);
    ContainsPlaceholderType = T->getContainedAutoType();
    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.
  // C++14 In generic lambdas allow 'auto' in their parameters.
  if (ContainsPlaceholderType &&
      (!SemaRef.getLangOpts().CPlusPlus11 || !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;  
      break;
    case Declarator::LambdaExprParameterContext:
      if (!(SemaRef.getLangOpts().CPlusPlus1y 
              && D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_auto))
        Error = 14;
      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;
      case TTK_Interface: Error = 4; /* Interface member */ break;
      }
      break;
    case Declarator::CXXCatchContext:
    case Declarator::ObjCCatchContext:
      Error = 5; // Exception declaration
      break;
    case Declarator::TemplateParamContext:
      Error = 6; // Template parameter
      break;
    case Declarator::BlockLiteralContext:
      Error = 7; // Block literal
      break;
    case Declarator::TemplateTypeArgContext:
      Error = 8; // Template type argument
      break;
    case Declarator::AliasDeclContext:
    case Declarator::AliasTemplateContext:
      Error = 10; // Type alias
      break;
    case Declarator::TrailingReturnContext:
      if (!SemaRef.getLangOpts().CPlusPlus1y)
        Error = 11; // Function return type
      break;
    case Declarator::ConversionIdContext:
      if (!SemaRef.getLangOpts().CPlusPlus1y)
        Error = 12; // conversion-type-id
      break;
    case Declarator::TypeNameContext:
      Error = 13; // 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 = 9;

    // In Objective-C it is an error to use 'auto' on a function declarator.
    if (D.isFunctionDeclarator())
      Error = 11;

    // 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().CPlusPlus11 && 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;
          }
        }
      }
    }

    SourceRange AutoRange = D.getDeclSpec().getTypeSpecTypeLoc();
    if (D.getName().getKind() == UnqualifiedId::IK_ConversionFunctionId)
      AutoRange = D.getName().getSourceRange();

    if (Error != -1) {
      const bool IsDeclTypeAuto = 
          D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_decltype_auto;
      SemaRef.Diag(AutoRange.getBegin(), diag::err_auto_not_allowed)
        << IsDeclTypeAuto << Error << AutoRange;
      T = SemaRef.Context.IntTy;
      D.setInvalidType(true);
    } else
      SemaRef.Diag(AutoRange.getBegin(),
                   diag::warn_cxx98_compat_auto_type_specifier)
        << AutoRange;
  }

  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);
      D.setInvalidType(true);
      break;
    case Declarator::TypeNameContext:
    case Declarator::ConversionIdContext:
    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);
      D.setInvalidType(true);
      break;
    case Declarator::PrototypeContext:
    case Declarator::LambdaExprParameterContext:
    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);
      D.setInvalidType(true);
      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);
      D.setInvalidType(true);
      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.NumParams > 1)
    return;

  // An initializer for a reference must have exactly one argument.
  if (RT->isReferenceType() && FTI.NumParams != 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().getStorageClassSpec()
        != 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.NumParams ? 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.NumParams > 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.Params[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, ParenRange.getBegin());
      if (Init.empty() && S.LangOpts.CPlusPlus11)
        Init = "{}";
      if (!Init.empty())
        S.Diag(DeclType.Loc, diag::note_empty_parens_zero_initialize)
          << FixItHint::CreateReplacement(ParenRange, Init);
    }
  }
}

/// Helper for figuring out the default CC for a function declarator type.  If
/// this is the outermost chunk, then we can determine the CC from the
/// declarator context.  If not, then this could be either a member function
/// type or normal function type.
static CallingConv
getCCForDeclaratorChunk(Sema &S, Declarator &D,
                        const DeclaratorChunk::FunctionTypeInfo &FTI,
                        unsigned ChunkIndex) {
  assert(D.getTypeObject(ChunkIndex).Kind == DeclaratorChunk::Function);

  bool IsCXXInstanceMethod = false;

  if (S.getLangOpts().CPlusPlus) {
    // Look inwards through parentheses to see if this chunk will form a
    // member pointer type or if we're the declarator.  Any type attributes
    // between here and there will override the CC we choose here.
    unsigned I = ChunkIndex;
    bool FoundNonParen = false;
    while (I && !FoundNonParen) {
      --I;
      if (D.getTypeObject(I).Kind != DeclaratorChunk::Paren)
        FoundNonParen = true;
    }

    if (FoundNonParen) {
      // If we're not the declarator, we're a regular function type unless we're
      // in a member pointer.
      IsCXXInstanceMethod =
          D.getTypeObject(I).Kind == DeclaratorChunk::MemberPointer;
    } else {
      // We're the innermost decl chunk, so must be a function declarator.
      assert(D.isFunctionDeclarator());

      // If we're inside a record, we're declaring a method, but it could be
      // explicitly or implicitly static.
      IsCXXInstanceMethod =
          D.isFirstDeclarationOfMember() &&
          D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
          !D.isStaticMember();
    }
  }

  return S.Context.getDefaultCallingConvention(FTI.isVariadic,
                                               IsCXXInstanceMethod);
}

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();

  // 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);

  // If T is 'decltype(auto)', the only declarators we can have are parens
  // and at most one function declarator if this is a function declaration.
  if (const AutoType *AT = T->getAs<AutoType>()) {
    if (AT->isDecltypeAuto()) {
      for (unsigned I = 0, E = D.getNumTypeObjects(); I != E; ++I) {
        unsigned Index = E - I - 1;
        DeclaratorChunk &DeclChunk = D.getTypeObject(Index);
        unsigned DiagId = diag::err_decltype_auto_compound_type;
        unsigned DiagKind = 0;
        switch (DeclChunk.Kind) {
        case DeclaratorChunk::Paren:
          continue;
        case DeclaratorChunk::Function: {
          unsigned FnIndex;
          if (D.isFunctionDeclarationContext() &&
              D.isFunctionDeclarator(FnIndex) && FnIndex == Index)
            continue;
          DiagId = diag::err_decltype_auto_function_declarator_not_declaration;
          break;
        }
        case DeclaratorChunk::Pointer:
        case DeclaratorChunk::BlockPointer:
        case DeclaratorChunk::MemberPointer:
          DiagKind = 0;
          break;
        case DeclaratorChunk::Reference:
          DiagKind = 1;
          break;
        case DeclaratorChunk::Array:
          DiagKind = 2;
          break;
        }

        S.Diag(DeclChunk.Loc, DiagId) << DiagKind;
        D.setInvalidType(true);
        break;
      }
    }
  }

  // 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);

      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;
          }
        }
      }
      const AutoType *AT = T->getContainedAutoType();
      // Allow arrays of auto if we are a generic lambda parameter.
      // i.e. [](auto (&array)[5]) { return array[0]; }; OK
      if (AT && D.getContext() != Declarator::LambdaExprParameterContext) {
        // We've already diagnosed this for decltype(auto).
        if (!AT->isDecltypeAuto())
          S.Diag(DeclType.Loc, diag::err_illegal_decl_array_of_auto)
            << getPrintableNameForEntity(Name) << T;
        T = QualType();
        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().containsPlaceholderType() &&
            !FTI.hasTrailingReturnType() && chunkIndex == 0 &&
            !S.getLangOpts().CPlusPlus1y) {
          S.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
                 D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_auto
                     ? diag::err_auto_missing_trailing_return
                     : diag::err_deduced_return_type);
          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) ||
                      cast<AutoType>(T)->isDecltypeAuto())) {
            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()) {
        if (S.getLangOpts().OpenCL) {
          if (!S.getOpenCLOptions().cl_khr_fp16) {
            S.Diag(D.getIdentifierLoc(), diag::err_opencl_half_return) << T;
            D.setInvalidType(true);
          } 
        } else {
          S.Diag(D.getIdentifierLoc(),
            diag::err_parameters_retval_cannot_have_fp16_type) << 1;
          D.setInvalidType(true);
        }
      }

      // Methods cannot return interface types. All ObjC objects are
      // passed by reference.
      if (T->isObjCObjectType()) {
        SourceLocation DiagLoc, FixitLoc;
        if (TInfo) {
          DiagLoc = TInfo->getTypeLoc().getLocStart();
          FixitLoc = S.PP.getLocForEndOfToken(TInfo->getTypeLoc().getLocEnd());
        } else {
          DiagLoc = D.getDeclSpec().getTypeSpecTypeLoc();
          FixitLoc = S.PP.getLocForEndOfToken(D.getDeclSpec().getLocEnd());
        }
        S.Diag(DiagLoc, diag::err_object_cannot_be_passed_returned_by_value)
          << 0 << T
          << FixItHint::CreateInsertion(FixitLoc, "*");

        T = Context.getObjCObjectPointerType(T);
        if (TInfo) {
          TypeLocBuilder TLB;
          TLB.pushFullCopy(TInfo->getTypeLoc());
          ObjCObjectPointerTypeLoc TLoc = TLB.push<ObjCObjectPointerTypeLoc>(T);
          TLoc.setStarLoc(FixitLoc);
          TInfo = TLB.getTypeSourceInfo(Context, T);
        }

        D.setInvalidType(true);
      }

      // cv-qualifiers on return types are pointless except when the type is a
      // class type in C++.
      if ((T.getCVRQualifiers() || T->isAtomicType()) &&
          !(S.getLangOpts().CPlusPlus &&
            (T->isDependentType() || T->isRecordType())))
        diagnoseIgnoredFunctionQualifiers(S, T, D, chunkIndex);

      // Objective-C ARC ownership qualifiers are ignored on the function
      // return type (by type canonicalization). Complain if this attribute
      // was written here.
      if (T.getQualifiers().hasObjCLifetime()) {
        SourceLocation AttrLoc;
        if (chunkIndex + 1 < D.getNumTypeObjects()) {
          DeclaratorChunk ReturnTypeChunk = D.getTypeObject(<