lib/Sema/SemaDeclAttr.cpp

//===--- SemaDeclAttr.cpp - Declaration Attribute Handling ----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements decl-related attribute processing.
//
//===----------------------------------------------------------------------===//

#include "clang/Sema/SemaInternal.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Mangle.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Scope.h"
#include "llvm/ADT/StringExtras.h"
using namespace clang;
using namespace sema;

namespace AttributeLangSupport {
  enum LANG {
    C,
    Cpp,
    ObjC
  };
}

//===----------------------------------------------------------------------===//
//  Helper functions
//===----------------------------------------------------------------------===//

/// isFunctionOrMethod - Return true if the given decl has function
/// type (function or function-typed variable) or an Objective-C
/// method.
static bool isFunctionOrMethod(const Decl *D) {
  return (D->getFunctionType() != NULL) || isa<ObjCMethodDecl>(D);
}

/// Return true if the given decl has a declarator that should have
/// been processed by Sema::GetTypeForDeclarator.
static bool hasDeclarator(const Decl *D) {
  // In some sense, TypedefDecl really *ought* to be a DeclaratorDecl.
  return isa<DeclaratorDecl>(D) || isa<BlockDecl>(D) || isa<TypedefNameDecl>(D) ||
         isa<ObjCPropertyDecl>(D);
}

/// hasFunctionProto - Return true if the given decl has a argument
/// information. This decl should have already passed
/// isFunctionOrMethod or isFunctionOrMethodOrBlock.
static bool hasFunctionProto(const Decl *D) {
  if (const FunctionType *FnTy = D->getFunctionType())
    return isa<FunctionProtoType>(FnTy);
  return isa<ObjCMethodDecl>(D) || isa<BlockDecl>(D);
}

/// getFunctionOrMethodNumParams - Return number of function or method
/// parameters. It is an error to call this on a K&R function (use
/// hasFunctionProto first).
static unsigned getFunctionOrMethodNumParams(const Decl *D) {
  if (const FunctionType *FnTy = D->getFunctionType())
    return cast<FunctionProtoType>(FnTy)->getNumParams();
  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
    return BD->getNumParams();
  return cast<ObjCMethodDecl>(D)->param_size();
}

static QualType getFunctionOrMethodParamType(const Decl *D, unsigned Idx) {
  if (const FunctionType *FnTy = D->getFunctionType())
    return cast<FunctionProtoType>(FnTy)->getParamType(Idx);
  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
    return BD->getParamDecl(Idx)->getType();

  return cast<ObjCMethodDecl>(D)->param_begin()[Idx]->getType();
}

static QualType getFunctionOrMethodResultType(const Decl *D) {
  if (const FunctionType *FnTy = D->getFunctionType())
    return cast<FunctionProtoType>(FnTy)->getReturnType();
  return cast<ObjCMethodDecl>(D)->getReturnType();
}

static bool isFunctionOrMethodVariadic(const Decl *D) {
  if (const FunctionType *FnTy = D->getFunctionType()) {
    const FunctionProtoType *proto = cast<FunctionProtoType>(FnTy);
    return proto->isVariadic();
  } else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
    return BD->isVariadic();
  else {
    return cast<ObjCMethodDecl>(D)->isVariadic();
  }
}

static bool isInstanceMethod(const Decl *D) {
  if (const CXXMethodDecl *MethodDecl = dyn_cast<CXXMethodDecl>(D))
    return MethodDecl->isInstance();
  return false;
}

static inline bool isNSStringType(QualType T, ASTContext &Ctx) {
  const ObjCObjectPointerType *PT = T->getAs<ObjCObjectPointerType>();
  if (!PT)
    return false;

  ObjCInterfaceDecl *Cls = PT->getObjectType()->getInterface();
  if (!Cls)
    return false;

  IdentifierInfo* ClsName = Cls->getIdentifier();

  // FIXME: Should we walk the chain of classes?
  return ClsName == &Ctx.Idents.get("NSString") ||
         ClsName == &Ctx.Idents.get("NSMutableString");
}

static inline bool isCFStringType(QualType T, ASTContext &Ctx) {
  const PointerType *PT = T->getAs<PointerType>();
  if (!PT)
    return false;

  const RecordType *RT = PT->getPointeeType()->getAs<RecordType>();
  if (!RT)
    return false;

  const RecordDecl *RD = RT->getDecl();
  if (RD->getTagKind() != TTK_Struct)
    return false;

  return RD->getIdentifier() == &Ctx.Idents.get("__CFString");
}

static unsigned getNumAttributeArgs(const AttributeList &Attr) {
  // FIXME: Include the type in the argument list.
  return Attr.getNumArgs() + Attr.hasParsedType();
}

/// \brief Check if the attribute has exactly as many args as Num. May
/// output an error.
static bool checkAttributeNumArgs(Sema &S, const AttributeList &Attr,
                                  unsigned Num) {
  if (getNumAttributeArgs(Attr) != Num) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments)
      << Attr.getName() << Num;
    return false;
  }

  return true;
}

/// \brief Check if the attribute has at least as many args as Num. May
/// output an error.
static bool checkAttributeAtLeastNumArgs(Sema &S, const AttributeList &Attr,
                                         unsigned Num) {
  if (getNumAttributeArgs(Attr) < Num) {
    S.Diag(Attr.getLoc(), diag::err_attribute_too_few_arguments)
      << Attr.getName() << Num;
    return false;
  }

  return true;
}

/// \brief If Expr is a valid integer constant, get the value of the integer
/// expression and return success or failure. May output an error.
static bool checkUInt32Argument(Sema &S, const AttributeList &Attr,
                                const Expr *Expr, uint32_t &Val,
                                unsigned Idx = UINT_MAX) {
  llvm::APSInt I(32);
  if (Expr->isTypeDependent() || Expr->isValueDependent() ||
      !Expr->isIntegerConstantExpr(I, S.Context)) {
    if (Idx != UINT_MAX)
      S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
        << Attr.getName() << Idx << AANT_ArgumentIntegerConstant
        << Expr->getSourceRange();
    else
      S.Diag(Attr.getLoc(), diag::err_attribute_argument_type)
        << Attr.getName() << AANT_ArgumentIntegerConstant
        << Expr->getSourceRange();
    return false;
  }
  Val = (uint32_t)I.getZExtValue();
  return true;
}

/// \brief Diagnose mutually exclusive attributes when present on a given
/// declaration. Returns true if diagnosed.
template <typename AttrTy>
static bool checkAttrMutualExclusion(Sema &S, Decl *D,
                                     const AttributeList &Attr) {
  if (AttrTy *A = D->getAttr<AttrTy>()) {
    S.Diag(Attr.getLoc(), diag::err_attributes_are_not_compatible)
      << Attr.getName() << A;
    return true;
  }
  return false;
}

/// \brief Check if IdxExpr is a valid parameter index for a function or
/// instance method D.  May output an error.
///
/// \returns true if IdxExpr is a valid index.
static bool checkFunctionOrMethodParameterIndex(Sema &S, const Decl *D,
                                                const AttributeList &Attr,
                                                unsigned AttrArgNum,
                                                const Expr *IdxExpr,
                                                uint64_t &Idx) {
  assert(isFunctionOrMethod(D));

  // In C++ the implicit 'this' function parameter also counts.
  // Parameters are counted from one.
  bool HP = hasFunctionProto(D);
  bool HasImplicitThisParam = isInstanceMethod(D);
  bool IV = HP && isFunctionOrMethodVariadic(D);
  unsigned NumParams =
      (HP ? getFunctionOrMethodNumParams(D) : 0) + HasImplicitThisParam;

  llvm::APSInt IdxInt;
  if (IdxExpr->isTypeDependent() || IdxExpr->isValueDependent() ||
      !IdxExpr->isIntegerConstantExpr(IdxInt, S.Context)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
      << Attr.getName() << AttrArgNum << AANT_ArgumentIntegerConstant
      << IdxExpr->getSourceRange();
    return false;
  }

  Idx = IdxInt.getLimitedValue();
  if (Idx < 1 || (!IV && Idx > NumParams)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_out_of_bounds)
      << Attr.getName() << AttrArgNum << IdxExpr->getSourceRange();
    return false;
  }
  Idx--; // Convert to zero-based.
  if (HasImplicitThisParam) {
    if (Idx == 0) {
      S.Diag(Attr.getLoc(),
             diag::err_attribute_invalid_implicit_this_argument)
        << Attr.getName() << IdxExpr->getSourceRange();
      return false;
    }
    --Idx;
  }

  return true;
}

/// \brief Check if the argument \p ArgNum of \p Attr is a ASCII string literal.
/// If not emit an error and return false. If the argument is an identifier it
/// will emit an error with a fixit hint and treat it as if it was a string
/// literal.
bool Sema::checkStringLiteralArgumentAttr(const AttributeList &Attr,
                                          unsigned ArgNum, StringRef &Str,
                                          SourceLocation *ArgLocation) {
  // Look for identifiers. If we have one emit a hint to fix it to a literal.
  if (Attr.isArgIdent(ArgNum)) {
    IdentifierLoc *Loc = Attr.getArgAsIdent(ArgNum);
    Diag(Loc->Loc, diag::err_attribute_argument_type)
        << Attr.getName() << AANT_ArgumentString
        << FixItHint::CreateInsertion(Loc->Loc, "\"")
        << FixItHint::CreateInsertion(PP.getLocForEndOfToken(Loc->Loc), "\"");
    Str = Loc->Ident->getName();
    if (ArgLocation)
      *ArgLocation = Loc->Loc;
    return true;
  }

  // Now check for an actual string literal.
  Expr *ArgExpr = Attr.getArgAsExpr(ArgNum);
  StringLiteral *Literal = dyn_cast<StringLiteral>(ArgExpr->IgnoreParenCasts());
  if (ArgLocation)
    *ArgLocation = ArgExpr->getLocStart();

  if (!Literal || !Literal->isAscii()) {
    Diag(ArgExpr->getLocStart(), diag::err_attribute_argument_type)
        << Attr.getName() << AANT_ArgumentString;
    return false;
  }

  Str = Literal->getString();
  return true;
}

/// \brief Applies the given attribute to the Decl without performing any
/// additional semantic checking.
template <typename AttrType>
static void handleSimpleAttribute(Sema &S, Decl *D,
                                  const AttributeList &Attr) {
  D->addAttr(::new (S.Context) AttrType(Attr.getRange(), S.Context,
                                        Attr.getAttributeSpellingListIndex()));
}

/// \brief Check if the passed-in expression is of type int or bool.
static bool isIntOrBool(Expr *Exp) {
  QualType QT = Exp->getType();
  return QT->isBooleanType() || QT->isIntegerType();
}


// Check to see if the type is a smart pointer of some kind.  We assume
// it's a smart pointer if it defines both operator-> and operator*.
static bool threadSafetyCheckIsSmartPointer(Sema &S, const RecordType* RT) {
  DeclContextLookupConstResult Res1 = RT->getDecl()->lookup(
    S.Context.DeclarationNames.getCXXOperatorName(OO_Star));
  if (Res1.empty())
    return false;

  DeclContextLookupConstResult Res2 = RT->getDecl()->lookup(
    S.Context.DeclarationNames.getCXXOperatorName(OO_Arrow));
  if (Res2.empty())
    return false;

  return true;
}

/// \brief Check if passed in Decl is a pointer type.
/// Note that this function may produce an error message.
/// \return true if the Decl is a pointer type; false otherwise
static bool threadSafetyCheckIsPointer(Sema &S, const Decl *D,
                                       const AttributeList &Attr) {
  const ValueDecl *vd = cast<ValueDecl>(D);
  QualType QT = vd->getType();
  if (QT->isAnyPointerType())
    return true;

  if (const RecordType *RT = QT->getAs<RecordType>()) {
    // If it's an incomplete type, it could be a smart pointer; skip it.
    // (We don't want to force template instantiation if we can avoid it,
    // since that would alter the order in which templates are instantiated.)
    if (RT->isIncompleteType())
      return true;

    if (threadSafetyCheckIsSmartPointer(S, RT))
      return true;
  }

  S.Diag(Attr.getLoc(), diag::warn_thread_attribute_decl_not_pointer)
    << Attr.getName() << QT;
  return false;
}

/// \brief Checks that the passed in QualType either is of RecordType or points
/// to RecordType. Returns the relevant RecordType, null if it does not exit.
static const RecordType *getRecordType(QualType QT) {
  if (const RecordType *RT = QT->getAs<RecordType>())
    return RT;

  // Now check if we point to record type.
  if (const PointerType *PT = QT->getAs<PointerType>())
    return PT->getPointeeType()->getAs<RecordType>();

  return 0;
}

static bool checkRecordTypeForCapability(Sema &S, QualType Ty) {
  const RecordType *RT = getRecordType(Ty);

  if (!RT)
    return false;

  // Don't check for the capability if the class hasn't been defined yet.
  if (RT->isIncompleteType())
    return true;

  // Allow smart pointers to be used as capability objects.
  // FIXME -- Check the type that the smart pointer points to.
  if (threadSafetyCheckIsSmartPointer(S, RT))
    return true;

  // Check if the record itself has a capability.
  RecordDecl *RD = RT->getDecl();
  if (RD->hasAttr<CapabilityAttr>())
    return true;

  // Else check if any base classes have a capability.
  if (CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
    CXXBasePaths BPaths(false, false);
    if (CRD->lookupInBases([](const CXXBaseSpecifier *BS, CXXBasePath &P,
      void *) {
      return BS->getType()->getAs<RecordType>()
        ->getDecl()->hasAttr<CapabilityAttr>();
    }, 0, BPaths))
      return true;
  }
  return false;
}

static bool checkTypedefTypeForCapability(QualType Ty) {
  const auto *TD = Ty->getAs<TypedefType>();
  if (!TD)
    return false;

  TypedefNameDecl *TN = TD->getDecl();
  if (!TN)
    return false;

  return TN->hasAttr<CapabilityAttr>();
}

static bool typeHasCapability(Sema &S, QualType Ty) {
  if (checkTypedefTypeForCapability(Ty))
    return true;

  if (checkRecordTypeForCapability(S, Ty))
    return true;

  return false;
}

static bool isCapabilityExpr(Sema &S, const Expr *Ex) {
  // Capability expressions are simple expressions involving the boolean logic
  // operators &&, || or !, a simple DeclRefExpr, CastExpr or a ParenExpr. Once
  // a DeclRefExpr is found, its type should be checked to determine whether it
  // is a capability or not.

  if (const auto *E = dyn_cast<DeclRefExpr>(Ex))
    return typeHasCapability(S, E->getType());
  else if (const auto *E = dyn_cast<CastExpr>(Ex))
    return isCapabilityExpr(S, E->getSubExpr());
  else if (const auto *E = dyn_cast<ParenExpr>(Ex))
    return isCapabilityExpr(S, E->getSubExpr());
  else if (const auto *E = dyn_cast<UnaryOperator>(Ex)) {
    if (E->getOpcode() == UO_LNot)
      return isCapabilityExpr(S, E->getSubExpr());
    return false;
  } else if (const auto *E = dyn_cast<BinaryOperator>(Ex)) {
    if (E->getOpcode() == BO_LAnd || E->getOpcode() == BO_LOr)
      return isCapabilityExpr(S, E->getLHS()) &&
             isCapabilityExpr(S, E->getRHS());
    return false;
  }

  return false;
}

/// \brief Checks that all attribute arguments, starting from Sidx, resolve to
/// a capability object.
/// \param Sidx The attribute argument index to start checking with.
/// \param ParamIdxOk Whether an argument can be indexing into a function
/// parameter list.
static void checkAttrArgsAreCapabilityObjs(Sema &S, Decl *D,
                                           const AttributeList &Attr,
                                           SmallVectorImpl<Expr *> &Args,
                                           int Sidx = 0,
                                           bool ParamIdxOk = false) {
  for (unsigned Idx = Sidx; Idx < Attr.getNumArgs(); ++Idx) {
    Expr *ArgExp = Attr.getArgAsExpr(Idx);

    if (ArgExp->isTypeDependent()) {
      // FIXME -- need to check this again on template instantiation
      Args.push_back(ArgExp);
      continue;
    }

    if (StringLiteral *StrLit = dyn_cast<StringLiteral>(ArgExp)) {
      if (StrLit->getLength() == 0 ||
          (StrLit->isAscii() && StrLit->getString() == StringRef("*"))) {
        // Pass empty strings to the analyzer without warnings.
        // Treat "*" as the universal lock.
        Args.push_back(ArgExp);
        continue;
      }

      // We allow constant strings to be used as a placeholder for expressions
      // that are not valid C++ syntax, but warn that they are ignored.
      S.Diag(Attr.getLoc(), diag::warn_thread_attribute_ignored) <<
        Attr.getName();
      Args.push_back(ArgExp);
      continue;
    }

    QualType ArgTy = ArgExp->getType();

    // A pointer to member expression of the form  &MyClass::mu is treated
    // specially -- we need to look at the type of the member.
    if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(ArgExp))
      if (UOp->getOpcode() == UO_AddrOf)
        if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(UOp->getSubExpr()))
          if (DRE->getDecl()->isCXXInstanceMember())
            ArgTy = DRE->getDecl()->getType();

    // First see if we can just cast to record type, or pointer to record type.
    const RecordType *RT = getRecordType(ArgTy);

    // Now check if we index into a record type function param.
    if(!RT && ParamIdxOk) {
      FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
      IntegerLiteral *IL = dyn_cast<IntegerLiteral>(ArgExp);
      if(FD && IL) {
        unsigned int NumParams = FD->getNumParams();
        llvm::APInt ArgValue = IL->getValue();
        uint64_t ParamIdxFromOne = ArgValue.getZExtValue();
        uint64_t ParamIdxFromZero = ParamIdxFromOne - 1;
        if(!ArgValue.isStrictlyPositive() || ParamIdxFromOne > NumParams) {
          S.Diag(Attr.getLoc(), diag::err_attribute_argument_out_of_range)
            << Attr.getName() << Idx + 1 << NumParams;
          continue;
        }
        ArgTy = FD->getParamDecl(ParamIdxFromZero)->getType();
      }
    }

    // If the type does not have a capability, see if the components of the
    // expression have capabilities. This allows for writing C code where the
    // capability may be on the type, and the expression is a capability
    // boolean logic expression. Eg) requires_capability(A || B && !C)
    if (!typeHasCapability(S, ArgTy) && !isCapabilityExpr(S, ArgExp))
      S.Diag(Attr.getLoc(), diag::warn_thread_attribute_argument_not_lockable)
          << Attr.getName() << ArgTy;

    Args.push_back(ArgExp);
  }
}

//===----------------------------------------------------------------------===//
// Attribute Implementations
//===----------------------------------------------------------------------===//

// FIXME: All this manual attribute parsing code is gross. At the
// least add some helper functions to check most argument patterns (#
// and types of args).

static void handlePtGuardedVarAttr(Sema &S, Decl *D,
                                   const AttributeList &Attr) {
  if (!threadSafetyCheckIsPointer(S, D, Attr))
    return;

  D->addAttr(::new (S.Context)
             PtGuardedVarAttr(Attr.getRange(), S.Context,
                              Attr.getAttributeSpellingListIndex()));
}

static bool checkGuardedByAttrCommon(Sema &S, Decl *D,
                                     const AttributeList &Attr,
                                     Expr* &Arg) {
  SmallVector<Expr*, 1> Args;
  // check that all arguments are lockable objects
  checkAttrArgsAreCapabilityObjs(S, D, Attr, Args);
  unsigned Size = Args.size();
  if (Size != 1)
    return false;

  Arg = Args[0];

  return true;
}

static void handleGuardedByAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  Expr *Arg = 0;
  if (!checkGuardedByAttrCommon(S, D, Attr, Arg))
    return;

  D->addAttr(::new (S.Context) GuardedByAttr(Attr.getRange(), S.Context, Arg,
                                        Attr.getAttributeSpellingListIndex()));
}

static void handlePtGuardedByAttr(Sema &S, Decl *D,
                                  const AttributeList &Attr) {
  Expr *Arg = 0;
  if (!checkGuardedByAttrCommon(S, D, Attr, Arg))
    return;

  if (!threadSafetyCheckIsPointer(S, D, Attr))
    return;

  D->addAttr(::new (S.Context) PtGuardedByAttr(Attr.getRange(),
                                               S.Context, Arg,
                                        Attr.getAttributeSpellingListIndex()));
}

static bool checkAcquireOrderAttrCommon(Sema &S, Decl *D,
                                        const AttributeList &Attr,
                                        SmallVectorImpl<Expr *> &Args) {
  if (!checkAttributeAtLeastNumArgs(S, Attr, 1))
    return false;

  // Check that this attribute only applies to lockable types.
  QualType QT = cast<ValueDecl>(D)->getType();
  if (!QT->isDependentType()) {
    const RecordType *RT = getRecordType(QT);
    if (!RT || !RT->getDecl()->hasAttr<CapabilityAttr>()) {
      S.Diag(Attr.getLoc(), diag::warn_thread_attribute_decl_not_lockable)
        << Attr.getName();
      return false;
    }
  }

  // Check that all arguments are lockable objects.
  checkAttrArgsAreCapabilityObjs(S, D, Attr, Args);
  if (Args.empty())
    return false;

  return true;
}

static void handleAcquiredAfterAttr(Sema &S, Decl *D,
                                    const AttributeList &Attr) {
  SmallVector<Expr*, 1> Args;
  if (!checkAcquireOrderAttrCommon(S, D, Attr, Args))
    return;

  Expr **StartArg = &Args[0];
  D->addAttr(::new (S.Context)
             AcquiredAfterAttr(Attr.getRange(), S.Context,
                               StartArg, Args.size(),
                               Attr.getAttributeSpellingListIndex()));
}

static void handleAcquiredBeforeAttr(Sema &S, Decl *D,
                                     const AttributeList &Attr) {
  SmallVector<Expr*, 1> Args;
  if (!checkAcquireOrderAttrCommon(S, D, Attr, Args))
    return;

  Expr **StartArg = &Args[0];
  D->addAttr(::new (S.Context)
             AcquiredBeforeAttr(Attr.getRange(), S.Context,
                                StartArg, Args.size(),
                                Attr.getAttributeSpellingListIndex()));
}

static bool checkLockFunAttrCommon(Sema &S, Decl *D,
                                   const AttributeList &Attr,
                                   SmallVectorImpl<Expr *> &Args) {
  // zero or more arguments ok
  // check that all arguments are lockable objects
  checkAttrArgsAreCapabilityObjs(S, D, Attr, Args, 0, /*ParamIdxOk=*/true);

  return true;
}

static void handleAssertSharedLockAttr(Sema &S, Decl *D,
                                       const AttributeList &Attr) {
  SmallVector<Expr*, 1> Args;
  if (!checkLockFunAttrCommon(S, D, Attr, Args))
    return;

  unsigned Size = Args.size();
  Expr **StartArg = Size == 0 ? 0 : &Args[0];
  D->addAttr(::new (S.Context)
             AssertSharedLockAttr(Attr.getRange(), S.Context, StartArg, Size,
                                  Attr.getAttributeSpellingListIndex()));
}

static void handleAssertExclusiveLockAttr(Sema &S, Decl *D,
                                          const AttributeList &Attr) {
  SmallVector<Expr*, 1> Args;
  if (!checkLockFunAttrCommon(S, D, Attr, Args))
    return;

  unsigned Size = Args.size();
  Expr **StartArg = Size == 0 ? 0 : &Args[0];
  D->addAttr(::new (S.Context)
             AssertExclusiveLockAttr(Attr.getRange(), S.Context,
                                     StartArg, Size,
                                     Attr.getAttributeSpellingListIndex()));
}


static bool checkTryLockFunAttrCommon(Sema &S, Decl *D,
                                      const AttributeList &Attr,
                                      SmallVectorImpl<Expr *> &Args) {
  if (!checkAttributeAtLeastNumArgs(S, Attr, 1))
    return false;

  if (!isIntOrBool(Attr.getArgAsExpr(0))) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
      << Attr.getName() << 1 << AANT_ArgumentIntOrBool;
    return false;
  }

  // check that all arguments are lockable objects
  checkAttrArgsAreCapabilityObjs(S, D, Attr, Args, 1);

  return true;
}

static void handleSharedTrylockFunctionAttr(Sema &S, Decl *D,
                                            const AttributeList &Attr) {
  SmallVector<Expr*, 2> Args;
  if (!checkTryLockFunAttrCommon(S, D, Attr, Args))
    return;

  D->addAttr(::new (S.Context)
             SharedTrylockFunctionAttr(Attr.getRange(), S.Context,
                                       Attr.getArgAsExpr(0),
                                       Args.data(), Args.size(),
                                       Attr.getAttributeSpellingListIndex()));
}

static void handleExclusiveTrylockFunctionAttr(Sema &S, Decl *D,
                                               const AttributeList &Attr) {
  SmallVector<Expr*, 2> Args;
  if (!checkTryLockFunAttrCommon(S, D, Attr, Args))
    return;

  D->addAttr(::new (S.Context)
             ExclusiveTrylockFunctionAttr(Attr.getRange(), S.Context,
                                          Attr.getArgAsExpr(0),
                                          Args.data(), Args.size(),
                                          Attr.getAttributeSpellingListIndex()));
}

static void handleLockReturnedAttr(Sema &S, Decl *D,
                                   const AttributeList &Attr) {
  // check that the argument is lockable object
  SmallVector<Expr*, 1> Args;
  checkAttrArgsAreCapabilityObjs(S, D, Attr, Args);
  unsigned Size = Args.size();
  if (Size == 0)
    return;

  D->addAttr(::new (S.Context)
             LockReturnedAttr(Attr.getRange(), S.Context, Args[0],
                              Attr.getAttributeSpellingListIndex()));
}

static void handleLocksExcludedAttr(Sema &S, Decl *D,
                                    const AttributeList &Attr) {
  if (!checkAttributeAtLeastNumArgs(S, Attr, 1))
    return;

  // check that all arguments are lockable objects
  SmallVector<Expr*, 1> Args;
  checkAttrArgsAreCapabilityObjs(S, D, Attr, Args);
  unsigned Size = Args.size();
  if (Size == 0)
    return;
  Expr **StartArg = &Args[0];

  D->addAttr(::new (S.Context)
             LocksExcludedAttr(Attr.getRange(), S.Context, StartArg, Size,
                               Attr.getAttributeSpellingListIndex()));
}

static void handleEnableIfAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  Expr *Cond = Attr.getArgAsExpr(0);
  if (!Cond->isTypeDependent()) {
    ExprResult Converted = S.PerformContextuallyConvertToBool(Cond);
    if (Converted.isInvalid())
      return;
    Cond = Converted.take();
  }

  StringRef Msg;
  if (!S.checkStringLiteralArgumentAttr(Attr, 1, Msg))
    return;

  SmallVector<PartialDiagnosticAt, 8> Diags;
  if (!Cond->isValueDependent() &&
      !Expr::isPotentialConstantExprUnevaluated(Cond, cast<FunctionDecl>(D),
                                                Diags)) {
    S.Diag(Attr.getLoc(), diag::err_enable_if_never_constant_expr);
    for (int I = 0, N = Diags.size(); I != N; ++I)
      S.Diag(Diags[I].first, Diags[I].second);
    return;
  }

  D->addAttr(::new (S.Context)
             EnableIfAttr(Attr.getRange(), S.Context, Cond, Msg,
                          Attr.getAttributeSpellingListIndex()));
}

static void handleConsumableAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  ConsumableAttr::ConsumedState DefaultState;

  if (Attr.isArgIdent(0)) {
    IdentifierLoc *IL = Attr.getArgAsIdent(0);
    if (!ConsumableAttr::ConvertStrToConsumedState(IL->Ident->getName(),
                                                   DefaultState)) {
      S.Diag(IL->Loc, diag::warn_attribute_type_not_supported)
        << Attr.getName() << IL->Ident;
      return;
    }
  } else {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_type)
        << Attr.getName() << AANT_ArgumentIdentifier;
    return;
  }
  
  D->addAttr(::new (S.Context)
             ConsumableAttr(Attr.getRange(), S.Context, DefaultState,
                            Attr.getAttributeSpellingListIndex()));
}


static bool checkForConsumableClass(Sema &S, const CXXMethodDecl *MD,
                                        const AttributeList &Attr) {
  ASTContext &CurrContext = S.getASTContext();
  QualType ThisType = MD->getThisType(CurrContext)->getPointeeType();
  
  if (const CXXRecordDecl *RD = ThisType->getAsCXXRecordDecl()) {
    if (!RD->hasAttr<ConsumableAttr>()) {
      S.Diag(Attr.getLoc(), diag::warn_attr_on_unconsumable_class) <<
        RD->getNameAsString();
      
      return false;
    }
  }
  
  return true;
}


static void handleCallableWhenAttr(Sema &S, Decl *D,
                                   const AttributeList &Attr) {
  if (!checkAttributeAtLeastNumArgs(S, Attr, 1))
    return;
  
  if (!checkForConsumableClass(S, cast<CXXMethodDecl>(D), Attr))
    return;
  
  SmallVector<CallableWhenAttr::ConsumedState, 3> States;
  for (unsigned ArgIndex = 0; ArgIndex < Attr.getNumArgs(); ++ArgIndex) {
    CallableWhenAttr::ConsumedState CallableState;
    
    StringRef StateString;
    SourceLocation Loc;
    if (!S.checkStringLiteralArgumentAttr(Attr, ArgIndex, StateString, &Loc))
      return;

    if (!CallableWhenAttr::ConvertStrToConsumedState(StateString,
                                                     CallableState)) {
      S.Diag(Loc, diag::warn_attribute_type_not_supported)
        << Attr.getName() << StateString;
      return;
    }
      
    States.push_back(CallableState);
  }
  
  D->addAttr(::new (S.Context)
             CallableWhenAttr(Attr.getRange(), S.Context, States.data(),
               States.size(), Attr.getAttributeSpellingListIndex()));
}


static void handleParamTypestateAttr(Sema &S, Decl *D,
                                    const AttributeList &Attr) {
  if (!checkAttributeNumArgs(S, Attr, 1)) return;
    
  ParamTypestateAttr::ConsumedState ParamState;
  
  if (Attr.isArgIdent(0)) {
    IdentifierLoc *Ident = Attr.getArgAsIdent(0);
    StringRef StateString = Ident->Ident->getName();

    if (!ParamTypestateAttr::ConvertStrToConsumedState(StateString,
                                                       ParamState)) {
      S.Diag(Ident->Loc, diag::warn_attribute_type_not_supported)
        << Attr.getName() << StateString;
      return;
    }
  } else {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_type) <<
      Attr.getName() << AANT_ArgumentIdentifier;
    return;
  }
  
  // FIXME: This check is currently being done in the analysis.  It can be
  //        enabled here only after the parser propagates attributes at
  //        template specialization definition, not declaration.
  //QualType ReturnType = cast<ParmVarDecl>(D)->getType();
  //const CXXRecordDecl *RD = ReturnType->getAsCXXRecordDecl();
  //
  //if (!RD || !RD->hasAttr<ConsumableAttr>()) {
  //    S.Diag(Attr.getLoc(), diag::warn_return_state_for_unconsumable_type) <<
  //      ReturnType.getAsString();
  //    return;
  //}
  
  D->addAttr(::new (S.Context)
             ParamTypestateAttr(Attr.getRange(), S.Context, ParamState,
                                Attr.getAttributeSpellingListIndex()));
}


static void handleReturnTypestateAttr(Sema &S, Decl *D,
                                      const AttributeList &Attr) {
  if (!checkAttributeNumArgs(S, Attr, 1)) return;
  
  ReturnTypestateAttr::ConsumedState ReturnState;
  
  if (Attr.isArgIdent(0)) {
    IdentifierLoc *IL = Attr.getArgAsIdent(0);
    if (!ReturnTypestateAttr::ConvertStrToConsumedState(IL->Ident->getName(),
                                                        ReturnState)) {
      S.Diag(IL->Loc, diag::warn_attribute_type_not_supported)
        << Attr.getName() << IL->Ident;
      return;
    }
  } else {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_type) <<
      Attr.getName() << AANT_ArgumentIdentifier;
    return;
  }
  
  // FIXME: This check is currently being done in the analysis.  It can be
  //        enabled here only after the parser propagates attributes at
  //        template specialization definition, not declaration.
  //QualType ReturnType;
  //
  //if (const ParmVarDecl *Param = dyn_cast<ParmVarDecl>(D)) {
  //  ReturnType = Param->getType();
  //
  //} else if (const CXXConstructorDecl *Constructor =
  //             dyn_cast<CXXConstructorDecl>(D)) {
  //  ReturnType = Constructor->getThisType(S.getASTContext())->getPointeeType();
  //  
  //} else {
  //  
  //  ReturnType = cast<FunctionDecl>(D)->getCallResultType();
  //}
  //
  //const CXXRecordDecl *RD = ReturnType->getAsCXXRecordDecl();
  //
  //if (!RD || !RD->hasAttr<ConsumableAttr>()) {
  //    S.Diag(Attr.getLoc(), diag::warn_return_state_for_unconsumable_type) <<
  //      ReturnType.getAsString();
  //    return;
  //}
  
  D->addAttr(::new (S.Context)
             ReturnTypestateAttr(Attr.getRange(), S.Context, ReturnState,
                                 Attr.getAttributeSpellingListIndex()));
}


static void handleSetTypestateAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (!checkAttributeNumArgs(S, Attr, 1))
    return;
  
  if (!checkForConsumableClass(S, cast<CXXMethodDecl>(D), Attr))
    return;
  
  SetTypestateAttr::ConsumedState NewState;
  if (Attr.isArgIdent(0)) {
    IdentifierLoc *Ident = Attr.getArgAsIdent(0);
    StringRef Param = Ident->Ident->getName();
    if (!SetTypestateAttr::ConvertStrToConsumedState(Param, NewState)) {
      S.Diag(Ident->Loc, diag::warn_attribute_type_not_supported)
        << Attr.getName() << Param;
      return;
    }
  } else {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_type) <<
      Attr.getName() << AANT_ArgumentIdentifier;
    return;
  }
  
  D->addAttr(::new (S.Context)
             SetTypestateAttr(Attr.getRange(), S.Context, NewState,
                              Attr.getAttributeSpellingListIndex()));
}

static void handleTestTypestateAttr(Sema &S, Decl *D,
                                    const AttributeList &Attr) {
  if (!checkAttributeNumArgs(S, Attr, 1))
    return;
  
  if (!checkForConsumableClass(S, cast<CXXMethodDecl>(D), Attr))
    return;
  
  TestTypestateAttr::ConsumedState TestState;  
  if (Attr.isArgIdent(0)) {
    IdentifierLoc *Ident = Attr.getArgAsIdent(0);
    StringRef Param = Ident->Ident->getName();
    if (!TestTypestateAttr::ConvertStrToConsumedState(Param, TestState)) {
      S.Diag(Ident->Loc, diag::warn_attribute_type_not_supported)
        << Attr.getName() << Param;
      return;
    }
  } else {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_type) <<
      Attr.getName() << AANT_ArgumentIdentifier;
    return;
  }
  
  D->addAttr(::new (S.Context)
             TestTypestateAttr(Attr.getRange(), S.Context, TestState,
                                Attr.getAttributeSpellingListIndex()));
}

static void handleExtVectorTypeAttr(Sema &S, Scope *scope, Decl *D,
                                    const AttributeList &Attr) {
  // Remember this typedef decl, we will need it later for diagnostics.
  S.ExtVectorDecls.push_back(cast<TypedefNameDecl>(D));
}

static void handlePackedAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (TagDecl *TD = dyn_cast<TagDecl>(D))
    TD->addAttr(::new (S.Context) PackedAttr(Attr.getRange(), S.Context,
                                        Attr.getAttributeSpellingListIndex()));
  else if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
    // If the alignment is less than or equal to 8 bits, the packed attribute
    // has no effect.
    if (!FD->getType()->isDependentType() &&
        !FD->getType()->isIncompleteType() &&
        S.Context.getTypeAlign(FD->getType()) <= 8)
      S.Diag(Attr.getLoc(), diag::warn_attribute_ignored_for_field_of_type)
        << Attr.getName() << FD->getType();
    else
      FD->addAttr(::new (S.Context)
                  PackedAttr(Attr.getRange(), S.Context,
                             Attr.getAttributeSpellingListIndex()));
  } else
    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
}

static bool checkIBOutletCommon(Sema &S, Decl *D, const AttributeList &Attr) {
  // The IBOutlet/IBOutletCollection attributes only apply to instance
  // variables or properties of Objective-C classes.  The outlet must also
  // have an object reference type.
  if (const ObjCIvarDecl *VD = dyn_cast<ObjCIvarDecl>(D)) {
    if (!VD->getType()->getAs<ObjCObjectPointerType>()) {
      S.Diag(Attr.getLoc(), diag::warn_iboutlet_object_type)
        << Attr.getName() << VD->getType() << 0;
      return false;
    }
  }
  else if (const ObjCPropertyDecl *PD = dyn_cast<ObjCPropertyDecl>(D)) {
    if (!PD->getType()->getAs<ObjCObjectPointerType>()) {
      S.Diag(Attr.getLoc(), diag::warn_iboutlet_object_type)
        << Attr.getName() << PD->getType() << 1;
      return false;
    }
  }
  else {
    S.Diag(Attr.getLoc(), diag::warn_attribute_iboutlet) << Attr.getName();
    return false;
  }

  return true;
}

static void handleIBOutlet(Sema &S, Decl *D, const AttributeList &Attr) {
  if (!checkIBOutletCommon(S, D, Attr))
    return;

  D->addAttr(::new (S.Context)
             IBOutletAttr(Attr.getRange(), S.Context,
                          Attr.getAttributeSpellingListIndex()));
}

static void handleIBOutletCollection(Sema &S, Decl *D,
                                     const AttributeList &Attr) {

  // The iboutletcollection attribute can have zero or one arguments.
  if (Attr.getNumArgs() > 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments)
      << Attr.getName() << 1;
    return;
  }

  if (!checkIBOutletCommon(S, D, Attr))
    return;

  ParsedType PT;

  if (Attr.hasParsedType())
    PT = Attr.getTypeArg();
  else {
    PT = S.getTypeName(S.Context.Idents.get("NSObject"), Attr.getLoc(),
                       S.getScopeForContext(D->getDeclContext()->getParent()));
    if (!PT) {
      S.Diag(Attr.getLoc(), diag::err_iboutletcollection_type) << "NSObject";
      return;
    }
  }

  TypeSourceInfo *QTLoc = 0;
  QualType QT = S.GetTypeFromParser(PT, &QTLoc);
  if (!QTLoc)
    QTLoc = S.Context.getTrivialTypeSourceInfo(QT, Attr.getLoc());

  // Diagnose use of non-object type in iboutletcollection attribute.
  // FIXME. Gnu attribute extension ignores use of builtin types in
  // attributes. So, __attribute__((iboutletcollection(char))) will be
  // treated as __attribute__((iboutletcollection())).
  if (!QT->isObjCIdType() && !QT->isObjCObjectType()) {
    S.Diag(Attr.getLoc(),
           QT->isBuiltinType() ? diag::err_iboutletcollection_builtintype
                               : diag::err_iboutletcollection_type) << QT;
    return;
  }

  D->addAttr(::new (S.Context)
             IBOutletCollectionAttr(Attr.getRange(), S.Context, QTLoc,
                                    Attr.getAttributeSpellingListIndex()));
}

static void possibleTransparentUnionPointerType(QualType &T) {
  if (const RecordType *UT = T->getAsUnionType())
    if (UT && UT->getDecl()->hasAttr<TransparentUnionAttr>()) {
      RecordDecl *UD = UT->getDecl();
      for (const auto *I : UD->fields()) {
        QualType QT = I->getType();
        if (QT->isAnyPointerType() || QT->isBlockPointerType()) {
          T = QT;
          return;
        }
      }
    }
}

static bool attrNonNullArgCheck(Sema &S, QualType T, const AttributeList &Attr,
                                SourceRange R, bool isReturnValue = false) {
  T = T.getNonReferenceType();
  possibleTransparentUnionPointerType(T);

  if (!T->isAnyPointerType() && !T->isBlockPointerType()) {
    S.Diag(Attr.getLoc(),
           isReturnValue ? diag::warn_attribute_return_pointers_only
                         : diag::warn_attribute_pointers_only)
      << Attr.getName() << R;
    return false;
  }
  return true;
}

static void handleNonNullAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  SmallVector<unsigned, 8> NonNullArgs;
  for (unsigned i = 0; i < Attr.getNumArgs(); ++i) {
    Expr *Ex = Attr.getArgAsExpr(i);
    uint64_t Idx;
    if (!checkFunctionOrMethodParameterIndex(S, D, Attr, i + 1, Ex, Idx))
      return;

    // Is the function argument a pointer type?
    // FIXME: Should also highlight argument in decl in the diagnostic.
    if (!attrNonNullArgCheck(S, getFunctionOrMethodParamType(D, Idx), Attr,
                             Ex->getSourceRange()))
      continue;

    NonNullArgs.push_back(Idx);
  }

  // If no arguments were specified to __attribute__((nonnull)) then all pointer
  // arguments have a nonnull attribute.
  if (NonNullArgs.empty()) {
    for (unsigned i = 0, e = getFunctionOrMethodNumParams(D); i != e; ++i) {
      QualType T = getFunctionOrMethodParamType(D, i).getNonReferenceType();
      possibleTransparentUnionPointerType(T);
      if (T->isAnyPointerType() || T->isBlockPointerType())
        NonNullArgs.push_back(i);
    }

    // No pointer arguments?
    if (NonNullArgs.empty()) {
      // Warn the trivial case only if attribute is not coming from a
      // macro instantiation.
      if (Attr.getLoc().isFileID())
        S.Diag(Attr.getLoc(), diag::warn_attribute_nonnull_no_pointers);
      return;
    }
  }

  unsigned *start = &NonNullArgs[0];
  unsigned size = NonNullArgs.size();
  llvm::array_pod_sort(start, start + size);
  D->addAttr(::new (S.Context)
             NonNullAttr(Attr.getRange(), S.Context, start, size,
                         Attr.getAttributeSpellingListIndex()));
}

static void handleNonNullAttrParameter(Sema &S, ParmVarDecl *D,
                                       const AttributeList &Attr) {
  if (Attr.getNumArgs() > 0) {
    if (D->getFunctionType()) {
      handleNonNullAttr(S, D, Attr);
    } else {
      S.Diag(Attr.getLoc(), diag::warn_attribute_nonnull_parm_no_args)
        << D->getSourceRange();
    }
    return;
  }

  // Is the argument a pointer type?
  if (!attrNonNullArgCheck(S, D->getType(), Attr, D->getSourceRange()))
    return;

  D->addAttr(::new (S.Context)
             NonNullAttr(Attr.getRange(), S.Context, 0, 0,
                         Attr.getAttributeSpellingListIndex()));
}

static void handleReturnsNonNullAttr(Sema &S, Decl *D,
                                     const AttributeList &Attr) {
  QualType ResultType = getFunctionOrMethodResultType(D);
  if (!attrNonNullArgCheck(S, ResultType, Attr, Attr.getRange(),
                           /* isReturnValue */ true))
    return;

  D->addAttr(::new (S.Context)
            ReturnsNonNullAttr(Attr.getRange(), S.Context,
                               Attr.getAttributeSpellingListIndex()));
}

static void handleOwnershipAttr(Sema &S, Decl *D, const AttributeList &AL) {
  // This attribute must be applied to a function declaration. The first
  // argument to the attribute must be an identifier, the name of the resource,
  // for example: malloc. The following arguments must be argument indexes, the
  // arguments must be of integer type for Returns, otherwise of pointer type.
  // The difference between Holds and Takes is that a pointer may still be used
  // after being held. free() should be __attribute((ownership_takes)), whereas
  // a list append function may well be __attribute((ownership_holds)).

  if (!AL.isArgIdent(0)) {
    S.Diag(AL.getLoc(), diag::err_attribute_argument_n_type)
      << AL.getName() << 1 << AANT_ArgumentIdentifier;
    return;
  }

  // Figure out our Kind.
  OwnershipAttr::OwnershipKind K =
      OwnershipAttr(AL.getLoc(), S.Context, 0, 0, 0,
                    AL.getAttributeSpellingListIndex()).getOwnKind();

  // Check arguments.
  switch (K) {
  case OwnershipAttr::Takes:
  case OwnershipAttr::Holds:
    if (AL.getNumArgs() < 2) {
      S.Diag(AL.getLoc(), diag::err_attribute_too_few_arguments)
        << AL.getName() << 2;
      return;
    }
    break;
  case OwnershipAttr::Returns:
    if (AL.getNumArgs() > 2) {
      S.Diag(AL.getLoc(), diag::err_attribute_too_many_arguments)
        << AL.getName() << 1;
      return;
    }
    break;
  }

  IdentifierInfo *Module = AL.getArgAsIdent(0)->Ident;

  // Normalize the argument, __foo__ becomes foo.
  StringRef ModuleName = Module->getName();
  if (ModuleName.startswith("__") && ModuleName.endswith("__") &&
      ModuleName.size() > 4) {
    ModuleName = ModuleName.drop_front(2).drop_back(2);
    Module = &S.PP.getIdentifierTable().get(ModuleName);
  }

  SmallVector<unsigned, 8> OwnershipArgs;
  for (unsigned i = 1; i < AL.getNumArgs(); ++i) {
    Expr *Ex = AL.getArgAsExpr(i);
    uint64_t Idx;
    if (!checkFunctionOrMethodParameterIndex(S, D, AL, i, Ex, Idx))
      return;

    // Is the function argument a pointer type?
    QualType T = getFunctionOrMethodParamType(D, Idx);
    int Err = -1;  // No error
    switch (K) {
      case OwnershipAttr::Takes:
      case OwnershipAttr::Holds:
        if (!T->isAnyPointerType() && !T->isBlockPointerType())
          Err = 0;
        break;
      case OwnershipAttr::Returns:
        if (!T->isIntegerType())
          Err = 1;
        break;
    }
    if (-1 != Err) {
      S.Diag(AL.getLoc(), diag::err_ownership_type) << AL.getName() << Err
        << Ex->getSourceRange();
      return;
    }

    // Check we don't have a conflict with another ownership attribute.
    for (const auto *I : D->specific_attrs<OwnershipAttr>()) {
      // FIXME: A returns attribute should conflict with any returns attribute
      // with a different index too.
      if (I->getOwnKind() != K && I->args_end() !=
          std::find(I->args_begin(), I->args_end(), Idx)) {
        S.Diag(AL.getLoc(), diag::err_attributes_are_not_compatible)
          << AL.getName() << I;
        return;
      }
    }
    OwnershipArgs.push_back(Idx);
  }

  unsigned* start = OwnershipArgs.data();
  unsigned size = OwnershipArgs.size();
  llvm::array_pod_sort(start, start + size);

  D->addAttr(::new (S.Context)
             OwnershipAttr(AL.getLoc(), S.Context, Module, start, size,
                           AL.getAttributeSpellingListIndex()));
}

static void handleWeakRefAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  // Check the attribute arguments.
  if (Attr.getNumArgs() > 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments)
      << Attr.getName() << 1;
    return;
  }

  NamedDecl *nd = cast<NamedDecl>(D);

  // gcc rejects
  // class c {
  //   static int a __attribute__((weakref ("v2")));
  //   static int b() __attribute__((weakref ("f3")));
  // };
  // and ignores the attributes of
  // void f(void) {
  //   static int a __attribute__((weakref ("v2")));
  // }
  // we reject them
  const DeclContext *Ctx = D->getDeclContext()->getRedeclContext();
  if (!Ctx->isFileContext()) {
    S.Diag(Attr.getLoc(), diag::err_attribute_weakref_not_global_context)
      << nd;
    return;
  }

  // The GCC manual says
  //
  // At present, a declaration to which `weakref' is attached can only
  // be `static'.
  //
  // It also says
  //
  // Without a TARGET,
  // given as an argument to `weakref' or to `alias', `weakref' is
  // equivalent to `weak'.
  //
  // gcc 4.4.1 will accept
  // int a7 __attribute__((weakref));
  // as
  // int a7 __attribute__((weak));
  // This looks like a bug in gcc. We reject that for now. We should revisit
  // it if this behaviour is actually used.

  // GCC rejects
  // static ((alias ("y"), weakref)).
  // Should we? How to check that weakref is before or after alias?

  // FIXME: it would be good for us to keep the WeakRefAttr as-written instead
  // of transforming it into an AliasAttr.  The WeakRefAttr never uses the
  // StringRef parameter it was given anyway.
  StringRef Str;
  if (Attr.getNumArgs() && S.checkStringLiteralArgumentAttr(Attr, 0, Str))
    // GCC will accept anything as the argument of weakref. Should we
    // check for an existing decl?
    D->addAttr(::new (S.Context) AliasAttr(Attr.getRange(), S.Context, Str,
                                        Attr.getAttributeSpellingListIndex()));

  D->addAttr(::new (S.Context)
             WeakRefAttr(Attr.getRange(), S.Context,
                         Attr.getAttributeSpellingListIndex()));
}

static void handleAliasAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  StringRef Str;
  if (!S.checkStringLiteralArgumentAttr(Attr, 0, Str))
    return;

  if (S.Context.getTargetInfo().getTriple().isOSDarwin()) {
    S.Diag(Attr.getLoc(), diag::err_alias_not_supported_on_darwin);
    return;
  }

  // FIXME: check if target symbol exists in current file

  D->addAttr(::new (S.Context) AliasAttr(Attr.getRange(), S.Context, Str,
                                         Attr.getAttributeSpellingListIndex()));
}

static void handleColdAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (checkAttrMutualExclusion<HotAttr>(S, D, Attr))
    return;

  D->addAttr(::new (S.Context) ColdAttr(Attr.getRange(), S.Context,
                                        Attr.getAttributeSpellingListIndex()));
}

static void handleHotAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (checkAttrMutualExclusion<ColdAttr>(S, D, Attr))
    return;

  D->addAttr(::new (S.Context) HotAttr(Attr.getRange(), S.Context,
                                       Attr.getAttributeSpellingListIndex()));
}

static void handleTLSModelAttr(Sema &S, Decl *D,
                               const AttributeList &Attr) {
  StringRef Model;
  SourceLocation LiteralLoc;
  // Check that it is a string.
  if (!S.checkStringLiteralArgumentAttr(Attr, 0, Model, &LiteralLoc))
    return;

  // Check that the value.
  if (Model != "global-dynamic" && Model != "local-dynamic"
      && Model != "initial-exec" && Model != "local-exec") {
    S.Diag(LiteralLoc, diag::err_attr_tlsmodel_arg);
    return;
  }

  D->addAttr(::new (S.Context)
             TLSModelAttr(Attr.getRange(), S.Context, Model,
                          Attr.getAttributeSpellingListIndex()));
}

static void handleKernelAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (S.LangOpts.Renderscript) {
    D->addAttr(::new (S.Context) 
               KernelAttr(Attr.getRange(), S.Context,
                          Attr.getAttributeSpellingListIndex()));
  } else {
    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << "kernel";
  }
}

static void handleMallocAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    QualType RetTy = FD->getReturnType();
    if (RetTy->isAnyPointerType() || RetTy->isBlockPointerType()) {
      D->addAttr(::new (S.Context)
                 MallocAttr(Attr.getRange(), S.Context,
                            Attr.getAttributeSpellingListIndex()));
      return;
    }
  }

  S.Diag(Attr.getLoc(), diag::warn_attribute_malloc_pointer_only);
}

static void handleCommonAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (S.LangOpts.CPlusPlus) {
    S.Diag(Attr.getLoc(), diag::err_attribute_not_supported_in_lang)
      << Attr.getName() << AttributeLangSupport::Cpp;
    return;
  }

  D->addAttr(::new (S.Context) CommonAttr(Attr.getRange(), S.Context,
                                        Attr.getAttributeSpellingListIndex()));
}

static void handleNoReturnAttr(Sema &S, Decl *D, const AttributeList &attr) {
  if (hasDeclarator(D)) return;

  if (S.CheckNoReturnAttr(attr)) return;

  if (!isa<ObjCMethodDecl>(D)) {
    S.Diag(attr.getLoc(), diag::warn_attribute_wrong_decl_type)
      << attr.getName() << ExpectedFunctionOrMethod;
    return;
  }

  D->addAttr(::new (S.Context)
             NoReturnAttr(attr.getRange(), S.Context,
                          attr.getAttributeSpellingListIndex()));
}

bool Sema::CheckNoReturnAttr(const AttributeList &attr) {
  if (!checkAttributeNumArgs(*this, attr, 0)) {
    attr.setInvalid();
    return true;
  }

  return false;
}

static void handleAnalyzerNoReturnAttr(Sema &S, Decl *D,
                                       const AttributeList &Attr) {
  
  // The checking path for 'noreturn' and 'analyzer_noreturn' are different
  // because 'analyzer_noreturn' does not impact the type.
  if (!isFunctionOrMethod(D) && !isa<BlockDecl>(D)) {
    ValueDecl *VD = dyn_cast<ValueDecl>(D);
    if (VD == 0 || (!VD->getType()->isBlockPointerType()
                    && !VD->getType()->isFunctionPointerType())) {
      S.Diag(Attr.getLoc(),
             Attr.isCXX11Attribute() ? diag::err_attribute_wrong_decl_type
             : diag::warn_attribute_wrong_decl_type)
        << Attr.getName() << ExpectedFunctionMethodOrBlock;
      return;
    }
  }
  
  D->addAttr(::new (S.Context)
             AnalyzerNoReturnAttr(Attr.getRange(), S.Context,
                                  Attr.getAttributeSpellingListIndex()));
}

// PS3 PPU-specific.
static void handleVecReturnAttr(Sema &S, Decl *D, const AttributeList &Attr) {
/*
  Returning a Vector Class in Registers
  
  According to the PPU ABI specifications, a class with a single member of 
  vector type is returned in memory when used as the return value of a function.
  This results in inefficient code when implementing vector classes. To return
  the value in a single vector register, add the vecreturn attribute to the
  class definition. This attribute is also applicable to struct types.
  
  Example:
  
  struct Vector
  {
    __vector float xyzw;
  } __attribute__((vecreturn));
  
  Vector Add(Vector lhs, Vector rhs)
  {
    Vector result;
    result.xyzw = vec_add(lhs.xyzw, rhs.xyzw);
    return result; // This will be returned in a register
  }
*/
  if (VecReturnAttr *A = D->getAttr<VecReturnAttr>()) {
    S.Diag(Attr.getLoc(), diag::err_repeat_attribute) << A;
    return;
  }

  RecordDecl *record = cast<RecordDecl>(D);
  int count = 0;

  if (!isa<CXXRecordDecl>(record)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_vecreturn_only_vector_member);
    return;
  }

  if (!cast<CXXRecordDecl>(record)->isPOD()) {
    S.Diag(Attr.getLoc(), diag::err_attribute_vecreturn_only_pod_record);
    return;
  }

  for (const auto *I : record->fields()) {
    if ((count == 1) || !I->getType()->isVectorType()) {
      S.Diag(Attr.getLoc(), diag::err_attribute_vecreturn_only_vector_member);
      return;
    }
    count++;
  }

  D->addAttr(::new (S.Context)
             VecReturnAttr(Attr.getRange(), S.Context,
                           Attr.getAttributeSpellingListIndex()));
}

static void handleDependencyAttr(Sema &S, Scope *Scope, Decl *D,
                                 const AttributeList &Attr) {
  if (isa<ParmVarDecl>(D)) {
    // [[carries_dependency]] can only be applied to a parameter if it is a
    // parameter of a function declaration or lambda.
    if (!(Scope->getFlags() & clang::Scope::FunctionDeclarationScope)) {
      S.Diag(Attr.getLoc(),
             diag::err_carries_dependency_param_not_function_decl);
      return;
    }
  }

  D->addAttr(::new (S.Context) CarriesDependencyAttr(
                                   Attr.getRange(), S.Context,
                                   Attr.getAttributeSpellingListIndex()));
}

static void handleUsedAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
    if (VD->hasLocalStorage()) {
      S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
      return;
    }
  } else if (!isFunctionOrMethod(D)) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
      << Attr.getName() << ExpectedVariableOrFunction;
    return;
  }

  D->addAttr(::new (S.Context)
             UsedAttr(Attr.getRange(), S.Context,
                      Attr.getAttributeSpellingListIndex()));
}

static void handleConstructorAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  // check the attribute arguments.
  if (Attr.getNumArgs() > 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_too_many_arguments)
      << Attr.getName() << 1;
    return;
  }

  uint32_t priority = ConstructorAttr::DefaultPriority;
  if (Attr.getNumArgs() > 0 &&
      !checkUInt32Argument(S, Attr, Attr.getArgAsExpr(0), priority))
    return;

  D->addAttr(::new (S.Context)
             ConstructorAttr(Attr.getRange(), S.Context, priority,
                             Attr.getAttributeSpellingListIndex()));
}

static void handleDestructorAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  // check the attribute arguments.
  if (Attr.getNumArgs() > 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_too_many_arguments)
      << Attr.getName() << 1;
    return;
  }

  uint32_t priority = DestructorAttr::DefaultPriority;
  if (Attr.getNumArgs() > 0 &&
      !checkUInt32Argument(S, Attr, Attr.getArgAsExpr(0), priority))
    return;

  D->addAttr(::new (S.Context)
             DestructorAttr(Attr.getRange(), S.Context, priority,
                            Attr.getAttributeSpellingListIndex()));
}

template <typename AttrTy>
static void handleAttrWithMessage(Sema &S, Decl *D,
                                  const AttributeList &Attr) {
  unsigned NumArgs = Attr.getNumArgs();
  if (NumArgs > 1) {
    S.Diag(Attr.getLoc(), diag::err_attribute_too_many_arguments)
      << Attr.getName() << 1;
    return;
  }

  // Handle the case where the attribute has a text message.
  StringRef Str;
  if (NumArgs == 1 && !S.checkStringLiteralArgumentAttr(Attr, 0, Str))
    return;

  D->addAttr(::new (S.Context) AttrTy(Attr.getRange(), S.Context, Str,
                                      Attr.getAttributeSpellingListIndex()));
}

static void handleObjCSuppresProtocolAttr(Sema &S, Decl *D,
                                          const AttributeList &Attr) {
  if (!cast<ObjCProtocolDecl>(D)->isThisDeclarationADefinition()) {
    S.Diag(Attr.getLoc(), diag::err_objc_attr_protocol_requires_definition)
      << Attr.getName() << Attr.getRange();
    return;
  }

  D->addAttr(::new (S.Context)
          ObjCExplicitProtocolImplAttr(Attr.getRange(), S.Context,
                                       Attr.getAttributeSpellingListIndex()));
}

static bool checkAvailabilityAttr(Sema &S, SourceRange Range,
                                  IdentifierInfo *Platform,
                                  VersionTuple Introduced,
                                  VersionTuple Deprecated,
                                  VersionTuple Obsoleted) {
  StringRef PlatformName
    = AvailabilityAttr::getPrettyPlatformName(Platform->getName());
  if (PlatformName.empty())
    PlatformName = Platform->getName();

  // Ensure that Introduced <= Deprecated <= Obsoleted (although not all
  // of these steps are needed).
  if (!Introduced.empty() && !Deprecated.empty() &&
      !(Introduced <= Deprecated)) {
    S.Diag(Range.getBegin(), diag::warn_availability_version_ordering)
      << 1 << PlatformName << Deprecated.getAsString()
      << 0 << Introduced.getAsString();
    return true;
  }

  if (!Introduced.empty() && !Obsoleted.empty() &&
      !(Introduced <= Obsoleted)) {
    S.Diag(Range.getBegin(), diag::warn_availability_version_ordering)
      << 2 << PlatformName << Obsoleted.getAsString()
      << 0 << Introduced.getAsString();
    return true;
  }

  if (!Deprecated.empty() && !Obsoleted.empty() &&
      !(Deprecated <= Obsoleted)) {
    S.Diag(Range.getBegin(), diag::warn_availability_version_ordering)
      << 2 << PlatformName << Obsoleted.getAsString()
      << 1 << Deprecated.getAsString();
    return true;
  }

  return false;
}

/// \brief Check whether the two versions match.
///
/// If either version tuple is empty, then they are assumed to match. If
/// \p BeforeIsOkay is true, then \p X can be less than or equal to \p Y.
static bool versionsMatch(const VersionTuple &X, const VersionTuple &Y,
                          bool BeforeIsOkay) {
  if (X.empty() || Y.empty())
    return true;

  if (X == Y)
    return true;

  if (BeforeIsOkay && X < Y)
    return true;

  return false;
}

AvailabilityAttr *Sema::mergeAvailabilityAttr(NamedDecl *D, SourceRange Range,
                                              IdentifierInfo *Platform,
                                              VersionTuple Introduced,
                                              VersionTuple Deprecated,
                                              VersionTuple Obsoleted,
                                              bool IsUnavailable,
                                              StringRef Message,
                                              bool Override,
                                              unsigned AttrSpellingListIndex) {
  VersionTuple MergedIntroduced = Introduced;
  VersionTuple MergedDeprecated = Deprecated;
  VersionTuple MergedObsoleted = Obsoleted;
  bool FoundAny = false;

  if (D->hasAttrs()) {
    AttrVec &Attrs = D->getAttrs();
    for (unsigned i = 0, e = Attrs.size(); i != e;) {
      const AvailabilityAttr *OldAA = dyn_cast<AvailabilityAttr>(Attrs[i]);
      if (!OldAA) {
        ++i;
        continue;
      }

      IdentifierInfo *OldPlatform = OldAA->getPlatform();
      if (OldPlatform != Platform) {
        ++i;
        continue;
      }

      FoundAny = true;
      VersionTuple OldIntroduced = OldAA->getIntroduced();
      VersionTuple OldDeprecated = OldAA->getDeprecated();
      VersionTuple OldObsoleted = OldAA->getObsoleted();
      bool OldIsUnavailable = OldAA->getUnavailable();

      if (!versionsMatch(OldIntroduced, Introduced, Override) ||
          !versionsMatch(Deprecated, OldDeprecated, Override) ||
          !versionsMatch(Obsoleted, OldObsoleted, Override) ||
          !(OldIsUnavailable == IsUnavailable ||
            (Override && !OldIsUnavailable && IsUnavailable))) {
        if (Override) {
          int Which = -1;
          VersionTuple FirstVersion;
          VersionTuple SecondVersion;
          if (!versionsMatch(OldIntroduced, Introduced, Override)) {
            Which = 0;
            FirstVersion = OldIntroduced;
            SecondVersion = Introduced;
          } else if (!versionsMatch(Deprecated, OldDeprecated, Override)) {
            Which = 1;
            FirstVersion = Deprecated;
            SecondVersion = OldDeprecated;
          } else if (!versionsMatch(Obsoleted, OldObsoleted, Override)) {
            Which = 2;
            FirstVersion = Obsoleted;
            SecondVersion = OldObsoleted;
          }

          if (Which == -1) {
            Diag(OldAA->getLocation(),
                 diag::warn_mismatched_availability_override_unavail)
              << AvailabilityAttr::getPrettyPlatformName(Platform->getName());
          } else {
            Diag(OldAA->getLocation(),
                 diag::warn_mismatched_availability_override)
              << Which
              << AvailabilityAttr::getPrettyPlatformName(Platform->getName())
              << FirstVersion.getAsString() << SecondVersion.getAsString();
          }
          Diag(Range.getBegin(), diag::note_overridden_method);
        } else {
          Diag(OldAA->getLocation(), diag::warn_mismatched_availability);
          Diag(Range.getBegin(), diag::note_previous_attribute);
        }

        Attrs.erase(Attrs.begin() + i);
        --e;
        continue;
      }

      VersionTuple MergedIntroduced2 = MergedIntroduced;
      VersionTuple MergedDeprecated2 = MergedDeprecated;
      VersionTuple MergedObsoleted2 = MergedObsoleted;

      if (MergedIntroduced2.empty())
        MergedIntroduced2 = OldIntroduced;
      if (MergedDeprecated2.empty())
        MergedDeprecated2 = OldDeprecated;
      if (MergedObsoleted2.empty())
        MergedObsoleted2 = OldObsoleted;

      if (checkAvailabilityAttr(*this, OldAA->getRange(), Platform,
                                MergedIntroduced2, MergedDeprecated2,
                                MergedObsoleted2)) {
        Attrs.erase(Attrs.begin() + i);
        --e;
        continue;
      }

      MergedIntroduced = MergedIntroduced2;
      MergedDeprecated = MergedDeprecated2;
      MergedObsoleted = MergedObsoleted2;
      ++i;
    }
  }

  if (FoundAny &&
      MergedIntroduced == Introduced &&
      MergedDeprecated == Deprecated &&
      MergedObsoleted == Obsoleted)
    return NULL;

  // Only create a new attribute if !Override, but we want to do
  // the checking.
  if (!checkAvailabilityAttr(*this, Range, Platform, MergedIntroduced,
                             MergedDeprecated, MergedObsoleted) &&
      !Override) {
    return ::new (Context) AvailabilityAttr(Range, Context, Platform,
                                            Introduced, Deprecated,
                                            Obsoleted, IsUnavailable, Message,
                                            AttrSpellingListIndex);
  }
  return NULL;
}

static void handleAvailabilityAttr(Sema &S, Decl *D,
                                   const AttributeList &Attr) {
  if (!checkAttributeNumArgs(S, Attr, 1))
    return;
  IdentifierLoc *Platform = Attr.getArgAsIdent(0);
  unsigned Index = Attr.getAttributeSpellingListIndex();
  
  IdentifierInfo *II = Platform->Ident;
  if (AvailabilityAttr::getPrettyPlatformName(II->getName()).empty())
    S.Diag(Platform->Loc, diag::warn_availability_unknown_platform)
      << Platform->Ident;

  NamedDecl *ND = dyn_cast<NamedDecl>(D);
  if (!ND) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
    return;
  }

  AvailabilityChange Introduced = Attr.getAvailabilityIntroduced();
  AvailabilityChange Deprecated = Attr.getAvailabilityDeprecated();
  AvailabilityChange Obsoleted = Attr.getAvailabilityObsoleted();
  bool IsUnavailable = Attr.getUnavailableLoc().isValid();
  StringRef Str;
  if (const StringLiteral *SE =
          dyn_cast_or_null<StringLiteral>(Attr.getMessageExpr()))
    Str = SE->getString();

  AvailabilityAttr *NewAttr = S.mergeAvailabilityAttr(ND, Attr.getRange(), II,
                                                      Introduced.Version,
                                                      Deprecated.Version,
                                                      Obsoleted.Version,
                                                      IsUnavailable, Str,
                                                      /*Override=*/false,
                                                      Index);
  if (NewAttr)
    D->addAttr(NewAttr);
}

template <class T>
static T *mergeVisibilityAttr(Sema &S, Decl *D, SourceRange range,
                              typename T::VisibilityType value,
                              unsigned attrSpellingListIndex) {
  T *existingAttr = D->getAttr<T>();
  if (existingAttr) {
    typename T::VisibilityType existingValue = existingAttr->getVisibility();
    if (existingValue == value)
      return NULL;
    S.Diag(existingAttr->getLocation(), diag::err_mismatched_visibility);
    S.Diag(range.getBegin(), diag::note_previous_attribute);
    D->dropAttr<T>();
  }
  return ::new (S.Context) T(range, S.Context, value, attrSpellingListIndex);
}

VisibilityAttr *Sema::mergeVisibilityAttr(Decl *D, SourceRange Range,
                                          VisibilityAttr::VisibilityType Vis,
                                          unsigned AttrSpellingListIndex) {
  return ::mergeVisibilityAttr<VisibilityAttr>(*this, D, Range, Vis,
                                               AttrSpellingListIndex);
}

TypeVisibilityAttr *Sema::mergeTypeVisibilityAttr(Decl *D, SourceRange Range,
                                      TypeVisibilityAttr::VisibilityType Vis,
                                      unsigned AttrSpellingListIndex) {
  return ::mergeVisibilityAttr<TypeVisibilityAttr>(*this, D, Range, Vis,
                                                   AttrSpellingListIndex);
}

static void handleVisibilityAttr(Sema &S, Decl *D, const AttributeList &Attr,
                                 bool isTypeVisibility) {
  // Visibility attributes don't mean anything on a typedef.
  if (isa<TypedefNameDecl>(D)) {
    S.Diag(Attr.getRange().getBegin(), diag::warn_attribute_ignored)
      << Attr.getName();
    return;
  }

  // 'type_visibility' can only go on a type or namespace.
  if (isTypeVisibility &&
      !(isa<TagDecl>(D) ||
        isa<ObjCInterfaceDecl>(D) ||
        isa<NamespaceDecl>(D))) {
    S.Diag(Attr.getRange().getBegin(), diag::err_attribute_wrong_decl_type)
      << Attr.getName() << ExpectedTypeOrNamespace;
    return;
  }

  // Check that the argument is a string literal.
  StringRef TypeStr;
  SourceLocation LiteralLoc;
  if (!S.checkStringLiteralArgumentAttr(Attr, 0, TypeStr, &LiteralLoc))
    return;

  VisibilityAttr::VisibilityType type;
  if (!VisibilityAttr::ConvertStrToVisibilityType(TypeStr, type)) {
    S.Diag(LiteralLoc, diag::warn_attribute_type_not_supported)
      << Attr.getName() << TypeStr;
    return;
  }
  
  // Complain about attempts to use protected visibility on targets
  // (like Darwin) that don't support it.
  if (type == VisibilityAttr::Protected &&
      !S.Context.getTargetInfo().hasProtectedVisibility()) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_protected_visibility);
    type = VisibilityAttr::Default;
  }

  unsigned Index = Attr.getAttributeSpellingListIndex();
  clang::Attr *newAttr;
  if (isTypeVisibility) {
    newAttr = S.mergeTypeVisibilityAttr(D, Attr.getRange(),
                                    (TypeVisibilityAttr::VisibilityType) type,
                                        Index);
  } else {
    newAttr = S.mergeVisibilityAttr(D, Attr.getRange(), type, Index);
  }
  if (newAttr)
    D->addAttr(newAttr);
}

static void handleObjCMethodFamilyAttr(Sema &S, Decl *decl,
                                       const AttributeList &Attr) {
  ObjCMethodDecl *method = cast<ObjCMethodDecl>(decl);
  if (!Attr.isArgIdent(0)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
      << Attr.getName() << 1 << AANT_ArgumentIdentifier;
    return;
  }

  IdentifierLoc *IL = Attr.getArgAsIdent(0);
  ObjCMethodFamilyAttr::FamilyKind F;
  if (!ObjCMethodFamilyAttr::ConvertStrToFamilyKind(IL->Ident->getName(), F)) {
    S.Diag(IL->Loc, diag::warn_attribute_type_not_supported) << Attr.getName()
      << IL->Ident;
    return;
  }

  if (F == ObjCMethodFamilyAttr::OMF_init &&
      !method->getReturnType()->isObjCObjectPointerType()) {
    S.Diag(method->getLocation(), diag::err_init_method_bad_return_type)
        << method->getReturnType();
    // Ignore the attribute.
    return;
  }

  method->addAttr(new (S.Context) ObjCMethodFamilyAttr(Attr.getRange(),
                                                       S.Context, F,
                                        Attr.getAttributeSpellingListIndex()));
}

static void handleObjCNSObject(Sema &S, Decl *D, const AttributeList &Attr) {
  if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D)) {
    QualType T = TD->getUnderlyingType();
    if (!T->isCARCBridgableType()) {
      S.Diag(TD->getLocation(), diag::err_nsobject_attribute);
      return;
    }
  }
  else if (ObjCPropertyDecl *PD = dyn_cast<ObjCPropertyDecl>(D)) {
    QualType T = PD->getType();
    if (!T->isCARCBridgableType()) {
      S.Diag(PD->getLocation(), diag::err_nsobject_attribute);
      return;
    }
  }
  else {
    // It is okay to include this attribute on properties, e.g.:
    //
    //  @property (retain, nonatomic) struct Bork *Q __attribute__((NSObject));
    //
    // In this case it follows tradition and suppresses an error in the above
    // case.    
    S.Diag(D->getLocation(), diag::warn_nsobject_attribute);
  }
  D->addAttr(::new (S.Context)
             ObjCNSObjectAttr(Attr.getRange(), S.Context,
                              Attr.getAttributeSpellingListIndex()));
}

static void handleBlocksAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (!Attr.isArgIdent(0)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
      << Attr.getName() << 1 << AANT_ArgumentIdentifier;
    return;
  }

  IdentifierInfo *II = Attr.getArgAsIdent(0)->Ident;
  BlocksAttr::BlockType type;
  if (!BlocksAttr::ConvertStrToBlockType(II->getName(), type)) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_type_not_supported)
      << Attr.getName() << II;
    return;
  }

  D->addAttr(::new (S.Context)
             BlocksAttr(Attr.getRange(), S.Context, type,
                        Attr.getAttributeSpellingListIndex()));
}

static void handleSentinelAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  // check the attribute arguments.
  if (Attr.getNumArgs() > 2) {
    S.Diag(Attr.getLoc(), diag::err_attribute_too_many_arguments)
      << Attr.getName() << 2;
    return;
  }

  unsigned sentinel = (unsigned)SentinelAttr::DefaultSentinel;
  if (Attr.getNumArgs() > 0) {
    Expr *E = Attr.getArgAsExpr(0);
    llvm::APSInt Idx(32);
    if (E->isTypeDependent() || E->isValueDependent() ||
        !E->isIntegerConstantExpr(Idx, S.Context)) {
      S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
        << Attr.getName() << 1 << AANT_ArgumentIntegerConstant
        << E->getSourceRange();
      return;
    }

    if (Idx.isSigned() && Idx.isNegative()) {
      S.Diag(Attr.getLoc(), diag::err_attribute_sentinel_less_than_zero)
        << E->getSourceRange();
      return;
    }

    sentinel = Idx.getZExtValue();
  }

  unsigned nullPos = (unsigned)SentinelAttr::DefaultNullPos;
  if (Attr.getNumArgs() > 1) {
    Expr *E = Attr.getArgAsExpr(1);
    llvm::APSInt Idx(32);
    if (E->isTypeDependent() || E->isValueDependent() ||
        !E->isIntegerConstantExpr(Idx, S.Context)) {
      S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
        << Attr.getName() << 2 << AANT_ArgumentIntegerConstant
        << E->getSourceRange();
      return;
    }
    nullPos = Idx.getZExtValue();

    if ((Idx.isSigned() && Idx.isNegative()) || nullPos > 1) {
      // FIXME: This error message could be improved, it would be nice
      // to say what the bounds actually are.
      S.Diag(Attr.getLoc(), diag::err_attribute_sentinel_not_zero_or_one)
        << E->getSourceRange();
      return;
    }
  }

  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    const FunctionType *FT = FD->getType()->castAs<FunctionType>();
    if (isa<FunctionNoProtoType>(FT)) {
      S.Diag(Attr.getLoc(), diag::warn_attribute_sentinel_named_arguments);
      return;
    }

    if (!cast<FunctionProtoType>(FT)->isVariadic()) {
      S.Diag(Attr.getLoc(), diag::warn_attribute_sentinel_not_variadic) << 0;
      return;
    }
  } else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
    if (!MD->isVariadic()) {
      S.Diag(Attr.getLoc(), diag::warn_attribute_sentinel_not_variadic) << 0;
      return;
    }
  } else if (BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
    if (!BD->isVariadic()) {
      S.Diag(Attr.getLoc(), diag::warn_attribute_sentinel_not_variadic) << 1;
      return;
    }
  } else if (const VarDecl *V = dyn_cast<VarDecl>(D)) {
    QualType Ty = V->getType();
    if (Ty->isBlockPointerType() || Ty->isFunctionPointerType()) {
      const FunctionType *FT = Ty->isFunctionPointerType()
       ? D->getFunctionType()
       : Ty->getAs<BlockPointerType>()->getPointeeType()->getAs<FunctionType>();
      if (!cast<FunctionProtoType>(FT)->isVariadic()) {
        int m = Ty->isFunctionPointerType() ? 0 : 1;
        S.Diag(Attr.getLoc(), diag::warn_attribute_sentinel_not_variadic) << m;
        return;
      }
    } else {
      S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
        << Attr.getName() << ExpectedFunctionMethodOrBlock;
      return;
    }
  } else {
    S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
      << Attr.getName() << ExpectedFunctionMethodOrBlock;
    return;
  }
  D->addAttr(::new (S.Context)
             SentinelAttr(Attr.getRange(), S.Context, sentinel, nullPos,
                          Attr.getAttributeSpellingListIndex()));
}

static void handleWarnUnusedResult(Sema &S, Decl *D, const AttributeList &Attr) {
  if (D->getFunctionType() &&
      D->getFunctionType()->getReturnType()->isVoidType()) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_void_function_method)
      << Attr.getName() << 0;
    return;
  }
  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
    if (MD->getReturnType()->isVoidType()) {
      S.Diag(Attr.getLoc(), diag::warn_attribute_void_function_method)
      << Attr.getName() << 1;
      return;
    }
  
  D->addAttr(::new (S.Context) 
             WarnUnusedResultAttr(Attr.getRange(), S.Context,
                                  Attr.getAttributeSpellingListIndex()));
}

static void handleWeakImportAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  // weak_import only applies to variable & function declarations.
  bool isDef = false;
  if (!D->canBeWeakImported(isDef)) {
    if (isDef)
      S.Diag(Attr.getLoc(), diag::warn_attribute_invalid_on_definition)
        << "weak_import";
    else if (isa<ObjCPropertyDecl>(D) || isa<ObjCMethodDecl>(D) ||
             (S.Context.getTargetInfo().getTriple().isOSDarwin() &&
              (isa<ObjCInterfaceDecl>(D) || isa<EnumDecl>(D)))) {
      // Nothing to warn about here.
    } else
      S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
        << Attr.getName() << ExpectedVariableOrFunction;

    return;
  }

  D->addAttr(::new (S.Context)
             WeakImportAttr(Attr.getRange(), S.Context,
                            Attr.getAttributeSpellingListIndex()));
}

// Handles reqd_work_group_size and work_group_size_hint.
template <typename WorkGroupAttr>
static void handleWorkGroupSize(Sema &S, Decl *D,
                                const AttributeList &Attr) {
  uint32_t WGSize[3];
  for (unsigned i = 0; i < 3; ++i)
    if (!checkUInt32Argument(S, Attr, Attr.getArgAsExpr(i), WGSize[i], i))
      return;

  WorkGroupAttr *Existing = D->getAttr<WorkGroupAttr>();
  if (Existing && !(Existing->getXDim() == WGSize[0] &&
                    Existing->getYDim() == WGSize[1] &&
                    Existing->getZDim() == WGSize[2]))
    S.Diag(Attr.getLoc(), diag::warn_duplicate_attribute) << Attr.getName();

  D->addAttr(::new (S.Context) WorkGroupAttr(Attr.getRange(), S.Context,
                                             WGSize[0], WGSize[1], WGSize[2],
                                       Attr.getAttributeSpellingListIndex()));
}

static void handleVecTypeHint(Sema &S, Decl *D, const AttributeList &Attr) {
  if (!Attr.hasParsedType()) {
    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments)
      << Attr.getName() << 1;
    return;
  }

  TypeSourceInfo *ParmTSI = 0;
  QualType ParmType = S.GetTypeFromParser(Attr.getTypeArg(), &ParmTSI);
  assert(ParmTSI && "no type source info for attribute argument");

  if (!ParmType->isExtVectorType() && !ParmType->isFloatingType() &&
      (ParmType->isBooleanType() ||
       !ParmType->isIntegralType(S.getASTContext()))) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_vec_type_hint)
        << ParmType;
    return;
  }

  if (VecTypeHintAttr *A = D->getAttr<VecTypeHintAttr>()) {
    if (!S.Context.hasSameType(A->getTypeHint(), ParmType)) {
      S.Diag(Attr.getLoc(), diag::warn_duplicate_attribute) << Attr.getName();
      return;
    }
  }

  D->addAttr(::new (S.Context) VecTypeHintAttr(Attr.getLoc(), S.Context,
                                               ParmTSI,
                                        Attr.getAttributeSpellingListIndex()));
}

SectionAttr *Sema::mergeSectionAttr(Decl *D, SourceRange Range,
                                    StringRef Name,
                                    unsigned AttrSpellingListIndex) {
  if (SectionAttr *ExistingAttr = D->getAttr<SectionAttr>()) {
    if (ExistingAttr->getName() == Name)
      return NULL;
    Diag(ExistingAttr->getLocation(), diag::warn_mismatched_section);
    Diag(Range.getBegin(), diag::note_previous_attribute);
    return NULL;
  }
  return ::new (Context) SectionAttr(Range, Context, Name,
                                     AttrSpellingListIndex);
}

static void handleSectionAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  // Make sure that there is a string literal as the sections's single
  // argument.
  StringRef Str;
  SourceLocation LiteralLoc;
  if (!S.checkStringLiteralArgumentAttr(Attr, 0, Str, &LiteralLoc))
    return;

  // If the target wants to validate the section specifier, make it happen.
  std::string Error = S.Context.getTargetInfo().isValidSectionSpecifier(Str);
  if (!Error.empty()) {
    S.Diag(LiteralLoc, diag::err_attribute_section_invalid_for_target)
    << Error;
    return;
  }

  unsigned Index = Attr.getAttributeSpellingListIndex();
  SectionAttr *NewAttr = S.mergeSectionAttr(D, Attr.getRange(), Str, Index);
  if (NewAttr)
    D->addAttr(NewAttr);
}


static void handleCleanupAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  VarDecl *VD = cast<VarDecl>(D);
  if (!VD->hasLocalStorage()) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
    return;
  }

  Expr *E = Attr.getArgAsExpr(0);
  SourceLocation Loc = E->getExprLoc();
  FunctionDecl *FD = 0;
  DeclarationNameInfo NI;

  // gcc only allows for simple identifiers. Since we support more than gcc, we
  // will warn the user.
  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
    if (DRE->hasQualifier())
      S.Diag(Loc, diag::warn_cleanup_ext);
    FD = dyn_cast<FunctionDecl>(DRE->getDecl());
    NI = DRE->getNameInfo();
    if (!FD) {
      S.Diag(Loc, diag::err_attribute_cleanup_arg_not_function) << 1
        << NI.getName();
      return;
    }
  } else if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) {
    if (ULE->hasExplicitTemplateArgs())
      S.Diag(Loc, diag::warn_cleanup_ext);
    FD = S.ResolveSingleFunctionTemplateSpecialization(ULE, true);
    NI = ULE->getNameInfo();
    if (!FD) {
      S.Diag(Loc, diag::err_attribute_cleanup_arg_not_function) << 2
        << NI.getName();
      if (ULE->getType() == S.Context.OverloadTy)
        S.NoteAllOverloadCandidates(ULE);
      return;
    }
  } else {
    S.Diag(Loc, diag::err_attribute_cleanup_arg_not_function) << 0;
    return;
  }

  if (FD->getNumParams() != 1) {
    S.Diag(Loc, diag::err_attribute_cleanup_func_must_take_one_arg)
      << NI.getName();
    return;
  }

  // We're currently more strict than GCC about what function types we accept.
  // If this ever proves to be a problem it should be easy to fix.
  QualType Ty = S.Context.getPointerType(VD->getType());
  QualType ParamTy = FD->getParamDecl(0)->getType();
  if (S.CheckAssignmentConstraints(FD->getParamDecl(0)->getLocation(),
                                   ParamTy, Ty) != Sema::Compatible) {
    S.Diag(Loc, diag::err_attribute_cleanup_func_arg_incompatible_type)
      << NI.getName() << ParamTy << Ty;
    return;
  }

  D->addAttr(::new (S.Context)
             CleanupAttr(Attr.getRange(), S.Context, FD,
                         Attr.getAttributeSpellingListIndex()));
}

/// Handle __attribute__((format_arg((idx)))) attribute based on
/// http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
static void handleFormatArgAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  Expr *IdxExpr = Attr.getArgAsExpr(0);
  uint64_t Idx;
  if (!checkFunctionOrMethodParameterIndex(S, D, Attr, 1, IdxExpr, Idx))
    return;

  // make sure the format string is really a string
  QualType Ty = getFunctionOrMethodParamType(D, Idx);

  bool not_nsstring_type = !isNSStringType(Ty, S.Context);
  if (not_nsstring_type &&
      !isCFStringType(Ty, S.Context) &&
      (!Ty->isPointerType() ||
       !Ty->getAs<PointerType>()->getPointeeType()->isCharType())) {
    // FIXME: Should highlight the actual expression that has the wrong type.
    S.Diag(Attr.getLoc(), diag::err_format_attribute_not)
    << (not_nsstring_type ? "a string type" : "an NSString")
       << IdxExpr->getSourceRange();
    return;
  }
  Ty = getFunctionOrMethodResultType(D);
  if (!isNSStringType(Ty, S.Context) &&
      !isCFStringType(Ty, S.Context) &&
      (!Ty->isPointerType() ||
       !Ty->getAs<PointerType>()->getPointeeType()->isCharType())) {
    // FIXME: Should highlight the actual expression that has the wrong type.
    S.Diag(Attr.getLoc(), diag::err_format_attribute_result_not)
    << (not_nsstring_type ? "string type" : "NSString")
       << IdxExpr->getSourceRange();
    return;
  }

  // We cannot use the Idx returned from checkFunctionOrMethodParameterIndex
  // because that has corrected for the implicit this parameter, and is zero-
  // based.  The attribute expects what the user wrote explicitly.
  llvm::APSInt Val;
  IdxExpr->EvaluateAsInt(Val, S.Context);

  D->addAttr(::new (S.Context)
             FormatArgAttr(Attr.getRange(), S.Context, Val.getZExtValue(),
                           Attr.getAttributeSpellingListIndex()));
}

enum FormatAttrKind {
  CFStringFormat,
  NSStringFormat,
  StrftimeFormat,
  SupportedFormat,
  IgnoredFormat,
  InvalidFormat
};

/// getFormatAttrKind - Map from format attribute names to supported format
/// types.
static FormatAttrKind getFormatAttrKind(StringRef Format) {
  return llvm::StringSwitch<FormatAttrKind>(Format)
    // Check for formats that get handled specially.
    .Case("NSString", NSStringFormat)
    .Case("CFString", CFStringFormat)
    .Case("strftime", StrftimeFormat)

    // Otherwise, check for supported formats.
    .Cases("scanf", "printf", "printf0", "strfmon", SupportedFormat)
    .Cases("cmn_err", "vcmn_err", "zcmn_err", SupportedFormat)
    .Case("kprintf", SupportedFormat) // OpenBSD.

    .Cases("gcc_diag", "gcc_cdiag", "gcc_cxxdiag", "gcc_tdiag", IgnoredFormat)
    .Default(InvalidFormat);
}

/// Handle __attribute__((init_priority(priority))) attributes based on
/// http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Attributes.html
static void handleInitPriorityAttr(Sema &S, Decl *D,
                                   const AttributeList &Attr) {
  if (!S.getLangOpts().CPlusPlus) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
    return;
  }
  
  if (S.getCurFunctionOrMethodDecl()) {
    S.Diag(Attr.getLoc(), diag::err_init_priority_object_attr);
    Attr.setInvalid();
    return;
  }
  QualType T = cast<VarDecl>(D)->getType();
  if (S.Context.getAsArrayType(T))
    T = S.Context.getBaseElementType(T);
  if (!T->getAs<RecordType>()) {
    S.Diag(Attr.getLoc(), diag::err_init_priority_object_attr);
    Attr.setInvalid();
    return;
  }

  Expr *E = Attr.getArgAsExpr(0);
  uint32_t prioritynum;
  if (!checkUInt32Argument(S, Attr, E, prioritynum)) {
    Attr.setInvalid();
    return;
  }

  if (prioritynum < 101 || prioritynum > 65535) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_outof_range)
      << E->getSourceRange();
    Attr.setInvalid();
    return;
  }
  D->addAttr(::new (S.Context)
             InitPriorityAttr(Attr.getRange(), S.Context, prioritynum,
                              Attr.getAttributeSpellingListIndex()));
}

FormatAttr *Sema::mergeFormatAttr(Decl *D, SourceRange Range,
                                  IdentifierInfo *Format, int FormatIdx,
                                  int FirstArg,
                                  unsigned AttrSpellingListIndex) {
  // Check whether we already have an equivalent format attribute.
  for (auto *F : D->specific_attrs<FormatAttr>()) {
    if (F->getType() == Format &&
        F->getFormatIdx() == FormatIdx &&
        F->getFirstArg() == FirstArg) {
      // If we don't have a valid location for this attribute, adopt the
      // location.
      if (F->getLocation().isInvalid())
        F->setRange(Range);
      return NULL;
    }
  }

  return ::new (Context) FormatAttr(Range, Context, Format, FormatIdx,
                                    FirstArg, AttrSpellingListIndex);
}

/// Handle __attribute__((format(type,idx,firstarg))) attributes based on
/// http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
static void handleFormatAttr(Sema &S, Decl *D, const AttributeList &Attr) {
  if (!Attr.isArgIdent(0)) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_type)
      << Attr.getName() << 1 << AANT_ArgumentIdentifier;
    return;
  }

  // In C++ the implicit 'this' function parameter also counts, and they are
  // counted from one.
  bool HasImplicitThisParam = isInstanceMethod(D);
  unsigned NumArgs = getFunctionOrMethodNumParams(D) + HasImplicitThisParam;

  IdentifierInfo *II = Attr.getArgAsIdent(0)->Ident;
  StringRef Format = II->getName();

  // Normalize the argument, __foo__ becomes foo.
  if (Format.startswith("__") && Format.endswith("__")) {
    Format = Format.substr(2, Format.size() - 4);
    // If we've modified the string name, we need a new identifier for it.
    II = &S.Context.Idents.get(Format);
  }

  // Check for supported formats.
  FormatAttrKind Kind = getFormatAttrKind(Format);
  
  if (Kind == IgnoredFormat)
    return;
  
  if (Kind == InvalidFormat) {
    S.Diag(Attr.getLoc(), diag::warn_attribute_type_not_supported)
      << Attr.getName() << II->getName();
    return;
  }

  // checks for the 2nd argument
  Expr *IdxExpr = Attr.getArgAsExpr(1);
  uint32_t Idx;
  if (!checkUInt32Argument(S, Attr, IdxExpr, Idx, 2))
    return;

  if (Idx < 1 || Idx > NumArgs) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_out_of_bounds)
      << Attr.getName() << 2 << IdxExpr->getSourceRange();
    return;
  }

  // FIXME: Do we need to bounds check?
  unsigned ArgIdx = Idx - 1;

  if (HasImplicitThisParam) {
    if (ArgIdx == 0) {
      S.Diag(Attr.getLoc(),
             diag::err_format_attribute_implicit_this_format_string)
        << IdxExpr->getSourceRange();
      return;
    }
    ArgIdx--;
  }

  // make sure the format string is really a string
  QualType Ty = getFunctionOrMethodParamType(D, ArgIdx);

  if (Kind == CFStringFormat) {
    if (!isCFStringType(Ty, S.Context)) {
      S.Diag(Attr.getLoc(), diag::err_format_attribute_not)
        << "a CFString" << IdxExpr->getSourceRange();
      return;
    }
  } else if (Kind == NSStringFormat) {
    // FIXME: do we need to check if the type is NSString*?  What are the
    // semantics?
    if (!isNSStringType(Ty, S.Context)) {
      // FIXME: Should highlight the actual expression that has the wrong type.
      S.Diag(Attr.getLoc(), diag::err_format_attribute_not)
        << "an NSString" << IdxExpr->getSourceRange();
      return;
    }
  } else if (!Ty->isPointerType() ||
             !Ty->getAs<PointerType>()->getPointeeType()->isCharType()) {
    // FIXME: Should highlight the actual expression that has the wrong type.
    S.Diag(Attr.getLoc(), diag::err_format_attribute_not)
      << "a string type" << IdxExpr->getSourceRange();
    return;
  }

  // check the 3rd argument
  Expr *FirstArgExpr = Attr.getArgAsExpr(2);
  uint32_t FirstArg;
  if (!checkUInt32Argument(S, Attr, FirstArgExpr, FirstArg, 3))
    return;

  // check if the function is variadic if the 3rd argument non-zero
  if (FirstArg != 0) {
    if (isFunctionOrMethodVariadic(D)) {
      ++NumArgs; // +1 for ...
    } else {
      S.Diag(D->getLocation(), diag::err_format_attribute_requires_variadic);
      return;
    }
  }

  // strftime requires FirstArg to be 0 because it doesn't read from any
  // variable the input is just the current time + the format string.
  if (Kind == StrftimeFormat) {
    if (FirstArg != 0) {
      S.Diag(Attr.getLoc(), diag::err_format_strftime_third_parameter)
        << FirstArgExpr->getSourceRange();
      return;
    }
  // if 0 it disables parameter checking (to use with e.g. va_list)
  } else if (FirstArg != 0 && FirstArg != NumArgs) {
    S.Diag(Attr.getLoc(), diag::err_attribute_argument_out_of_bounds)
      << Attr.getName() << 3 << FirstArgExpr->getSourceRange();
    return;
  }

  FormatAttr *NewAttr = S.mergeFormatAttr(D, Attr.getRange(), II,
                                          Idx, FirstArg,
                                          Attr.getAttributeSpellingListIndex());
  if (NewAttr)
    D->addAttr(NewAttr);
}

static void handleTransparentUnionAttr(Sema &S, Decl *D,
                                       const AttributeList &Attr) {
  // Try to find the underlying union declaration.
  RecordDecl *RD = 0;
  TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D);
  if (