lib/Sema/SemaExpr.cpp

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

#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/LiteralSupport.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Parse/Designator.h"
#include "clang/Parse/Scope.h"
using namespace clang;


/// \brief Determine whether the use of this declaration is valid, and
/// emit any corresponding diagnostics.
///
/// This routine diagnoses various problems with referencing
/// declarations that can occur when using a declaration. For example,
/// it might warn if a deprecated or unavailable declaration is being
/// used, or produce an error (and return true) if a C++0x deleted
/// function is being used.
///
/// \returns true if there was an error (this declaration cannot be
/// referenced), false otherwise.
bool Sema::DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc) {
  // See if the decl is deprecated.
  if (D->getAttr<DeprecatedAttr>()) {
    // Implementing deprecated stuff requires referencing deprecated
    // stuff. Don't warn if we are implementing a deprecated
    // construct.
    bool isSilenced = false;
    
    if (NamedDecl *ND = getCurFunctionOrMethodDecl()) {
      // If this reference happens *in* a deprecated function or method, don't
      // warn.
      isSilenced = ND->getAttr<DeprecatedAttr>();
      
      // If this is an Objective-C method implementation, check to see if the
      // method was deprecated on the declaration, not the definition.
      if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(ND)) {
        // The semantic decl context of a ObjCMethodDecl is the
        // ObjCImplementationDecl.
        if (ObjCImplementationDecl *Impl
              = dyn_cast<ObjCImplementationDecl>(MD->getParent())) {
          
          MD = Impl->getClassInterface()->getMethod(MD->getSelector(),
                                                    MD->isInstanceMethod());
          isSilenced |= MD && MD->getAttr<DeprecatedAttr>();
        }
      }
    }
    
    if (!isSilenced)
      Diag(Loc, diag::warn_deprecated) << D->getDeclName();
  }

  // See if this is a deleted function.
  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    if (FD->isDeleted()) {
      Diag(Loc, diag::err_deleted_function_use);
      Diag(D->getLocation(), diag::note_unavailable_here) << true;
      return true;
    }
  }

  // See if the decl is unavailable
  if (D->getAttr<UnavailableAttr>()) {
    Diag(Loc, diag::warn_unavailable) << D->getDeclName();
    Diag(D->getLocation(), diag::note_unavailable_here) << 0;
  }

  return false;
}

/// DiagnoseSentinelCalls - This routine checks on method dispatch calls
/// (and other functions in future), which have been declared with sentinel 
/// attribute. It warns if call does not have the sentinel argument.
///
void Sema::DiagnoseSentinelCalls(NamedDecl *D, SourceLocation Loc,
                                 Expr **Args, unsigned NumArgs)
{
  const SentinelAttr *attr = D->getAttr<SentinelAttr>();
  if (!attr) 
    return;
  int sentinelPos = attr->getSentinel();
  int nullPos = attr->getNullPos();
  
  // FIXME. ObjCMethodDecl and FunctionDecl need be derived from the same common
  // base class. Then we won't be needing two versions of the same code.
  unsigned int i = 0;
  bool warnNotEnoughArgs = false;
  int isMethod = 0;
  if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
    // skip over named parameters.
    ObjCMethodDecl::param_iterator P, E = MD->param_end();
    for (P = MD->param_begin(); (P != E && i < NumArgs); ++P) {
      if (nullPos)
        --nullPos;
      else
        ++i;
    }
    warnNotEnoughArgs = (P != E || i >= NumArgs);
    isMethod = 1;
  } else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    // skip over named parameters.
    ObjCMethodDecl::param_iterator P, E = FD->param_end();
    for (P = FD->param_begin(); (P != E && i < NumArgs); ++P) {
      if (nullPos)
        --nullPos;
      else
        ++i;
    }
    warnNotEnoughArgs = (P != E || i >= NumArgs);
  } else if (VarDecl *V = dyn_cast<VarDecl>(D)) {
    // block or function pointer call.
    QualType Ty = V->getType();
    if (Ty->isBlockPointerType() || Ty->isFunctionPointerType()) {
      const FunctionType *FT = Ty->isFunctionPointerType() 
      ? Ty->getAs<PointerType>()->getPointeeType()->getAsFunctionType()
      : Ty->getAs<BlockPointerType>()->getPointeeType()->getAsFunctionType();
      if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) {
        unsigned NumArgsInProto = Proto->getNumArgs();
        unsigned k;
        for (k = 0; (k != NumArgsInProto && i < NumArgs); k++) {
          if (nullPos)
            --nullPos;
          else
            ++i;
        }
        warnNotEnoughArgs = (k != NumArgsInProto || i >= NumArgs);
      }
      if (Ty->isBlockPointerType())
        isMethod = 2;
    } else
      return;
  } else
    return;

  if (warnNotEnoughArgs) {
    Diag(Loc, diag::warn_not_enough_argument) << D->getDeclName();
    Diag(D->getLocation(), diag::note_sentinel_here) << isMethod;
    return;
  }
  int sentinel = i;
  while (sentinelPos > 0 && i < NumArgs-1) {
    --sentinelPos;
    ++i;
  }
  if (sentinelPos > 0) {
    Diag(Loc, diag::warn_not_enough_argument) << D->getDeclName();
    Diag(D->getLocation(), diag::note_sentinel_here) << isMethod;
    return;
  }
  while (i < NumArgs-1) {
    ++i;
    ++sentinel;
  }
  Expr *sentinelExpr = Args[sentinel];
  if (sentinelExpr && (!sentinelExpr->getType()->isPointerType() ||
                       !sentinelExpr->isNullPointerConstant(Context))) {
    Diag(Loc, diag::warn_missing_sentinel) << isMethod;
    Diag(D->getLocation(), diag::note_sentinel_here) << isMethod;
  }
  return;
}

SourceRange Sema::getExprRange(ExprTy *E) const {
  Expr *Ex = (Expr *)E;
  return Ex? Ex->getSourceRange() : SourceRange();
}

//===----------------------------------------------------------------------===//
//  Standard Promotions and Conversions
//===----------------------------------------------------------------------===//

/// DefaultFunctionArrayConversion (C99 6.3.2.1p3, C99 6.3.2.1p4).
void Sema::DefaultFunctionArrayConversion(Expr *&E) {
  QualType Ty = E->getType();
  assert(!Ty.isNull() && "DefaultFunctionArrayConversion - missing type");

  if (Ty->isFunctionType())
    ImpCastExprToType(E, Context.getPointerType(Ty));
  else if (Ty->isArrayType()) {
    // In C90 mode, arrays only promote to pointers if the array expression is
    // an lvalue.  The relevant legalese is C90 6.2.2.1p3: "an lvalue that has
    // type 'array of type' is converted to an expression that has type 'pointer
    // to type'...".  In C99 this was changed to: C99 6.3.2.1p3: "an expression
    // that has type 'array of type' ...".  The relevant change is "an lvalue"
    // (C90) to "an expression" (C99).
    //
    // C++ 4.2p1:
    // An lvalue or rvalue of type "array of N T" or "array of unknown bound of
    // T" can be converted to an rvalue of type "pointer to T".
    //
    if (getLangOptions().C99 || getLangOptions().CPlusPlus ||
        E->isLvalue(Context) == Expr::LV_Valid)
      ImpCastExprToType(E, Context.getArrayDecayedType(Ty),
                        CastExpr::CK_ArrayToPointerDecay);
  }
}

/// UsualUnaryConversions - Performs various conversions that are common to most
/// operators (C99 6.3). The conversions of array and function types are 
/// sometimes surpressed. For example, the array->pointer conversion doesn't
/// apply if the array is an argument to the sizeof or address (&) operators.
/// In these instances, this routine should *not* be called.
Expr *Sema::UsualUnaryConversions(Expr *&Expr) {
  QualType Ty = Expr->getType();
  assert(!Ty.isNull() && "UsualUnaryConversions - missing type");
  
  // C99 6.3.1.1p2:
  //
  //   The following may be used in an expression wherever an int or
  //   unsigned int may be used:
  //     - an object or expression with an integer type whose integer
  //       conversion rank is less than or equal to the rank of int
  //       and unsigned int.
  //     - A bit-field of type _Bool, int, signed int, or unsigned int.
  //
  //   If an int can represent all values of the original type, the
  //   value is converted to an int; otherwise, it is converted to an
  //   unsigned int. These are called the integer promotions. All
  //   other types are unchanged by the integer promotions.
  QualType PTy = Context.isPromotableBitField(Expr);
  if (!PTy.isNull()) {
    ImpCastExprToType(Expr, PTy);
    return Expr;
  }
  if (Ty->isPromotableIntegerType()) {
    QualType PT = Context.getPromotedIntegerType(Ty);
    ImpCastExprToType(Expr, PT);
    return Expr;
  }

  DefaultFunctionArrayConversion(Expr);
  return Expr;
}

/// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
/// do not have a prototype. Arguments that have type float are promoted to 
/// double. All other argument types are converted by UsualUnaryConversions().
void Sema::DefaultArgumentPromotion(Expr *&Expr) {
  QualType Ty = Expr->getType();
  assert(!Ty.isNull() && "DefaultArgumentPromotion - missing type");
  
  // If this is a 'float' (CVR qualified or typedef) promote to double.
  if (const BuiltinType *BT = Ty->getAsBuiltinType())
    if (BT->getKind() == BuiltinType::Float)
      return ImpCastExprToType(Expr, Context.DoubleTy);
  
  UsualUnaryConversions(Expr);
}

/// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
/// will warn if the resulting type is not a POD type, and rejects ObjC
/// interfaces passed by value.  This returns true if the argument type is
/// completely illegal.
bool Sema::DefaultVariadicArgumentPromotion(Expr *&Expr, VariadicCallType CT) {
  DefaultArgumentPromotion(Expr);
  
  if (Expr->getType()->isObjCInterfaceType()) {
    Diag(Expr->getLocStart(),
         diag::err_cannot_pass_objc_interface_to_vararg)
      << Expr->getType() << CT;
    return true;
  }
  
  if (!Expr->getType()->isPODType())
    Diag(Expr->getLocStart(), diag::warn_cannot_pass_non_pod_arg_to_vararg)
      << Expr->getType() << CT;

  return false;
}


/// UsualArithmeticConversions - Performs various conversions that are common to
/// binary operators (C99 6.3.1.8). If both operands aren't arithmetic, this
/// routine returns the first non-arithmetic type found. The client is 
/// responsible for emitting appropriate error diagnostics.
/// FIXME: verify the conversion rules for "complex int" are consistent with
/// GCC.
QualType Sema::UsualArithmeticConversions(Expr *&lhsExpr, Expr *&rhsExpr,
                                          bool isCompAssign) {
  if (!isCompAssign)
    UsualUnaryConversions(lhsExpr);

  UsualUnaryConversions(rhsExpr);

  // For conversion purposes, we ignore any qualifiers. 
  // For example, "const float" and "float" are equivalent.
  QualType lhs =
    Context.getCanonicalType(lhsExpr->getType()).getUnqualifiedType();
  QualType rhs = 
    Context.getCanonicalType(rhsExpr->getType()).getUnqualifiedType();

  // If both types are identical, no conversion is needed.
  if (lhs == rhs)
    return lhs;

  // If either side is a non-arithmetic type (e.g. a pointer), we are done.
  // The caller can deal with this (e.g. pointer + int).
  if (!lhs->isArithmeticType() || !rhs->isArithmeticType())
    return lhs;

  // Perform bitfield promotions.
  QualType LHSBitfieldPromoteTy = Context.isPromotableBitField(lhsExpr);
  if (!LHSBitfieldPromoteTy.isNull())
    lhs = LHSBitfieldPromoteTy;
  QualType RHSBitfieldPromoteTy = Context.isPromotableBitField(rhsExpr);
  if (!RHSBitfieldPromoteTy.isNull())
    rhs = RHSBitfieldPromoteTy;

  QualType destType = Context.UsualArithmeticConversionsType(lhs, rhs);
  if (!isCompAssign)
    ImpCastExprToType(lhsExpr, destType);
  ImpCastExprToType(rhsExpr, destType);
  return destType;
}

//===----------------------------------------------------------------------===//
//  Semantic Analysis for various Expression Types
//===----------------------------------------------------------------------===//


/// ActOnStringLiteral - The specified tokens were lexed as pasted string
/// fragments (e.g. "foo" "bar" L"baz").  The result string has to handle string
/// concatenation ([C99 5.1.1.2, translation phase #6]), so it may come from
/// multiple tokens.  However, the common case is that StringToks points to one
/// string.
///
Action::OwningExprResult
Sema::ActOnStringLiteral(const Token *StringToks, unsigned NumStringToks) {
  assert(NumStringToks && "Must have at least one string!");

  StringLiteralParser Literal(StringToks, NumStringToks, PP);
  if (Literal.hadError)
    return ExprError();

  llvm::SmallVector<SourceLocation, 4> StringTokLocs;
  for (unsigned i = 0; i != NumStringToks; ++i)
    StringTokLocs.push_back(StringToks[i].getLocation());

  QualType StrTy = Context.CharTy;
  if (Literal.AnyWide) StrTy = Context.getWCharType();
  if (Literal.Pascal) StrTy = Context.UnsignedCharTy;

  // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
  if (getLangOptions().CPlusPlus)
    StrTy.addConst();

  // Get an array type for the string, according to C99 6.4.5.  This includes
  // the nul terminator character as well as the string length for pascal
  // strings.
  StrTy = Context.getConstantArrayType(StrTy,
                                 llvm::APInt(32, Literal.GetNumStringChars()+1),
                                       ArrayType::Normal, 0);
  
  // Pass &StringTokLocs[0], StringTokLocs.size() to factory!
  return Owned(StringLiteral::Create(Context, Literal.GetString(), 
                                     Literal.GetStringLength(),
                                     Literal.AnyWide, StrTy,
                                     &StringTokLocs[0],
                                     StringTokLocs.size()));
}

/// ShouldSnapshotBlockValueReference - Return true if a reference inside of
/// CurBlock to VD should cause it to be snapshotted (as we do for auto
/// variables defined outside the block) or false if this is not needed (e.g.
/// for values inside the block or for globals).
///
/// This also keeps the 'hasBlockDeclRefExprs' in the BlockSemaInfo records
/// up-to-date.
///
static bool ShouldSnapshotBlockValueReference(BlockSemaInfo *CurBlock,
                                              ValueDecl *VD) {
  // If the value is defined inside the block, we couldn't snapshot it even if
  // we wanted to.
  if (CurBlock->TheDecl == VD->getDeclContext())
    return false;
  
  // If this is an enum constant or function, it is constant, don't snapshot.
  if (isa<EnumConstantDecl>(VD) || isa<FunctionDecl>(VD))
    return false;

  // If this is a reference to an extern, static, or global variable, no need to
  // snapshot it.
  // FIXME: What about 'const' variables in C++?
  if (const VarDecl *Var = dyn_cast<VarDecl>(VD))
    if (!Var->hasLocalStorage())
      return false;
  
  // Blocks that have these can't be constant.
  CurBlock->hasBlockDeclRefExprs = true;

  // If we have nested blocks, the decl may be declared in an outer block (in
  // which case that outer block doesn't get "hasBlockDeclRefExprs") or it may
  // be defined outside all of the current blocks (in which case the blocks do
  // all get the bit).  Walk the nesting chain.
  for (BlockSemaInfo *NextBlock = CurBlock->PrevBlockInfo; NextBlock;
       NextBlock = NextBlock->PrevBlockInfo) {
    // If we found the defining block for the variable, don't mark the block as
    // having a reference outside it.
    if (NextBlock->TheDecl == VD->getDeclContext())
      break;
    
    // Otherwise, the DeclRef from the inner block causes the outer one to need
    // a snapshot as well.
    NextBlock->hasBlockDeclRefExprs = true;
  }
  
  return true;
}  
    


/// ActOnIdentifierExpr - The parser read an identifier in expression context,
/// validate it per-C99 6.5.1.  HasTrailingLParen indicates whether this
/// identifier is used in a function call context.
/// SS is only used for a C++ qualified-id (foo::bar) to indicate the
/// class or namespace that the identifier must be a member of.
Sema::OwningExprResult Sema::ActOnIdentifierExpr(Scope *S, SourceLocation Loc,
                                                 IdentifierInfo &II,
                                                 bool HasTrailingLParen,
                                                 const CXXScopeSpec *SS,
                                                 bool isAddressOfOperand) {
  return ActOnDeclarationNameExpr(S, Loc, &II, HasTrailingLParen, SS,
                                  isAddressOfOperand);
}

/// BuildDeclRefExpr - Build either a DeclRefExpr or a
/// QualifiedDeclRefExpr based on whether or not SS is a
/// nested-name-specifier.
Sema::OwningExprResult
Sema::BuildDeclRefExpr(NamedDecl *D, QualType Ty, SourceLocation Loc,
                       bool TypeDependent, bool ValueDependent,
                       const CXXScopeSpec *SS) {
  if (Context.getCanonicalType(Ty) == Context.UndeducedAutoTy) {
    Diag(Loc,
         diag::err_auto_variable_cannot_appear_in_own_initializer) 
      << D->getDeclName();
    return ExprError();
  }
  
  if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext)) {
      if (const FunctionDecl *FD = MD->getParent()->isLocalClass()) {
        if (VD->hasLocalStorage() && VD->getDeclContext() != CurContext) {
          Diag(Loc, diag::err_reference_to_local_var_in_enclosing_function) 
            << D->getIdentifier() << FD->getDeclName();
          Diag(D->getLocation(), diag::note_local_variable_declared_here) 
            << D->getIdentifier();
          return ExprError();
        }
      }
    }
  }
  
  MarkDeclarationReferenced(Loc, D);
  
  Expr *E;
  if (SS && !SS->isEmpty()) {
    E = new (Context) QualifiedDeclRefExpr(D, Ty, Loc, TypeDependent, 
                                          ValueDependent, SS->getRange(),
                  static_cast<NestedNameSpecifier *>(SS->getScopeRep()));
  } else
    E = new (Context) DeclRefExpr(D, Ty, Loc, TypeDependent, ValueDependent);
  
  return Owned(E);
}

/// getObjectForAnonymousRecordDecl - Retrieve the (unnamed) field or
/// variable corresponding to the anonymous union or struct whose type
/// is Record.
static Decl *getObjectForAnonymousRecordDecl(ASTContext &Context,
                                             RecordDecl *Record) {
  assert(Record->isAnonymousStructOrUnion() && 
         "Record must be an anonymous struct or union!");
  
  // FIXME: Once Decls are directly linked together, this will be an O(1)
  // operation rather than a slow walk through DeclContext's vector (which
  // itself will be eliminated). DeclGroups might make this even better.
  DeclContext *Ctx = Record->getDeclContext();
  for (DeclContext::decl_iterator D = Ctx->decls_begin(), 
                               DEnd = Ctx->decls_end();
       D != DEnd; ++D) {
    if (*D == Record) {
      // The object for the anonymous struct/union directly
      // follows its type in the list of declarations.
      ++D;
      assert(D != DEnd && "Missing object for anonymous record");
      assert(!cast<NamedDecl>(*D)->getDeclName() && "Decl should be unnamed");
      return *D;
    }
  }

  assert(false && "Missing object for anonymous record");
  return 0;
}

/// \brief Given a field that represents a member of an anonymous
/// struct/union, build the path from that field's context to the
/// actual member.
///
/// Construct the sequence of field member references we'll have to
/// perform to get to the field in the anonymous union/struct. The
/// list of members is built from the field outward, so traverse it
/// backwards to go from an object in the current context to the field
/// we found.
///
/// \returns The variable from which the field access should begin,
/// for an anonymous struct/union that is not a member of another
/// class. Otherwise, returns NULL.
VarDecl *Sema::BuildAnonymousStructUnionMemberPath(FieldDecl *Field,
                                   llvm::SmallVectorImpl<FieldDecl *> &Path) {
  assert(Field->getDeclContext()->isRecord() &&
         cast<RecordDecl>(Field->getDeclContext())->isAnonymousStructOrUnion()
         && "Field must be stored inside an anonymous struct or union");

  Path.push_back(Field);
  VarDecl *BaseObject = 0;
  DeclContext *Ctx = Field->getDeclContext();
  do {
    RecordDecl *Record = cast<RecordDecl>(Ctx);
    Decl *AnonObject = getObjectForAnonymousRecordDecl(Context, Record);
    if (FieldDecl *AnonField = dyn_cast<FieldDecl>(AnonObject))
      Path.push_back(AnonField);
    else {
      BaseObject = cast<VarDecl>(AnonObject);
      break;
    }
    Ctx = Ctx->getParent();
  } while (Ctx->isRecord() && 
           cast<RecordDecl>(Ctx)->isAnonymousStructOrUnion());

  return BaseObject;
}

Sema::OwningExprResult
Sema::BuildAnonymousStructUnionMemberReference(SourceLocation Loc,
                                               FieldDecl *Field,
                                               Expr *BaseObjectExpr,
                                               SourceLocation OpLoc) {
  llvm::SmallVector<FieldDecl *, 4> AnonFields;
  VarDecl *BaseObject = BuildAnonymousStructUnionMemberPath(Field, 
                                                            AnonFields);

  // Build the expression that refers to the base object, from
  // which we will build a sequence of member references to each
  // of the anonymous union objects and, eventually, the field we
  // found via name lookup.
  bool BaseObjectIsPointer = false;
  unsigned ExtraQuals = 0;
  if (BaseObject) {
    // BaseObject is an anonymous struct/union variable (and is,
    // therefore, not part of another non-anonymous record).
    if (BaseObjectExpr) BaseObjectExpr->Destroy(Context);
    MarkDeclarationReferenced(Loc, BaseObject);
    BaseObjectExpr = new (Context) DeclRefExpr(BaseObject,BaseObject->getType(),
                                               SourceLocation());
    ExtraQuals 
      = Context.getCanonicalType(BaseObject->getType()).getCVRQualifiers();
  } else if (BaseObjectExpr) {
    // The caller provided the base object expression. Determine
    // whether its a pointer and whether it adds any qualifiers to the
    // anonymous struct/union fields we're looking into.
    QualType ObjectType = BaseObjectExpr->getType();
    if (const PointerType *ObjectPtr = ObjectType->getAs<PointerType>()) {
      BaseObjectIsPointer = true;
      ObjectType = ObjectPtr->getPointeeType();
    }
    ExtraQuals = Context.getCanonicalType(ObjectType).getCVRQualifiers();
  } else {
    // We've found a member of an anonymous struct/union that is
    // inside a non-anonymous struct/union, so in a well-formed
    // program our base object expression is "this".
    if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext)) {
      if (!MD->isStatic()) {
        QualType AnonFieldType 
          = Context.getTagDeclType(
                     cast<RecordDecl>(AnonFields.back()->getDeclContext()));
        QualType ThisType = Context.getTagDeclType(MD->getParent());
        if ((Context.getCanonicalType(AnonFieldType) 
               == Context.getCanonicalType(ThisType)) ||
            IsDerivedFrom(ThisType, AnonFieldType)) {
          // Our base object expression is "this".
          BaseObjectExpr = new (Context) CXXThisExpr(SourceLocation(),
                                                     MD->getThisType(Context));
          BaseObjectIsPointer = true;
        }
      } else {
        return ExprError(Diag(Loc,diag::err_invalid_member_use_in_static_method)
          << Field->getDeclName());
      }
      ExtraQuals = MD->getTypeQualifiers();
    }

    if (!BaseObjectExpr) 
      return ExprError(Diag(Loc, diag::err_invalid_non_static_member_use)
        << Field->getDeclName());
  }

  // Build the implicit member references to the field of the
  // anonymous struct/union.
  Expr *Result = BaseObjectExpr;
  unsigned BaseAddrSpace = BaseObjectExpr->getType().getAddressSpace();
  for (llvm::SmallVector<FieldDecl *, 4>::reverse_iterator
         FI = AnonFields.rbegin(), FIEnd = AnonFields.rend();
       FI != FIEnd; ++FI) {
    QualType MemberType = (*FI)->getType();
    if (!(*FI)->isMutable()) {
      unsigned combinedQualifiers 
        = MemberType.getCVRQualifiers() | ExtraQuals;
      MemberType = MemberType.getQualifiedType(combinedQualifiers);
    }
    if (BaseAddrSpace != MemberType.getAddressSpace())
      MemberType = Context.getAddrSpaceQualType(MemberType, BaseAddrSpace);
    MarkDeclarationReferenced(Loc, *FI);
    Result = new (Context) MemberExpr(Result, BaseObjectIsPointer, *FI,
                                      OpLoc, MemberType);
    BaseObjectIsPointer = false;
    ExtraQuals = Context.getCanonicalType(MemberType).getCVRQualifiers();
  }

  return Owned(Result);
}

/// ActOnDeclarationNameExpr - The parser has read some kind of name
/// (e.g., a C++ id-expression (C++ [expr.prim]p1)). This routine
/// performs lookup on that name and returns an expression that refers
/// to that name. This routine isn't directly called from the parser,
/// because the parser doesn't know about DeclarationName. Rather,
/// this routine is called by ActOnIdentifierExpr,
/// ActOnOperatorFunctionIdExpr, and ActOnConversionFunctionExpr,
/// which form the DeclarationName from the corresponding syntactic
/// forms.
///
/// HasTrailingLParen indicates whether this identifier is used in a
/// function call context.  LookupCtx is only used for a C++
/// qualified-id (foo::bar) to indicate the class or namespace that
/// the identifier must be a member of.
///
/// isAddressOfOperand means that this expression is the direct operand
/// of an address-of operator. This matters because this is the only
/// situation where a qualified name referencing a non-static member may
/// appear outside a member function of this class.
Sema::OwningExprResult
Sema::ActOnDeclarationNameExpr(Scope *S, SourceLocation Loc,
                               DeclarationName Name, bool HasTrailingLParen,
                               const CXXScopeSpec *SS, 
                               bool isAddressOfOperand) {
  // Could be enum-constant, value decl, instance variable, etc.
  if (SS && SS->isInvalid())
    return ExprError();

  // C++ [temp.dep.expr]p3:
  //   An id-expression is type-dependent if it contains:
  //     -- a nested-name-specifier that contains a class-name that
  //        names a dependent type.
  // FIXME: Member of the current instantiation.
  if (SS && isDependentScopeSpecifier(*SS)) {
    return Owned(new (Context) UnresolvedDeclRefExpr(Name, Context.DependentTy,
                                                     Loc, SS->getRange(), 
                static_cast<NestedNameSpecifier *>(SS->getScopeRep()),
                                                     isAddressOfOperand));
  }

  LookupResult Lookup = LookupParsedName(S, SS, Name, LookupOrdinaryName,
                                         false, true, Loc);

  if (Lookup.isAmbiguous()) {
    DiagnoseAmbiguousLookup(Lookup, Name, Loc,
                            SS && SS->isSet() ? SS->getRange()
                                              : SourceRange());
    return ExprError();
  }
  
  NamedDecl *D = Lookup.getAsDecl();

  // If this reference is in an Objective-C method, then ivar lookup happens as
  // well.
  IdentifierInfo *II = Name.getAsIdentifierInfo();
  if (II && getCurMethodDecl()) {
    // There are two cases to handle here.  1) scoped lookup could have failed,
    // in which case we should look for an ivar.  2) scoped lookup could have
    // found a decl, but that decl is outside the current instance method (i.e. 
    // a global variable).  In these two cases, we do a lookup for an ivar with 
    // this name, if the lookup sucedes, we replace it our current decl.
    if (D == 0 || D->isDefinedOutsideFunctionOrMethod()) {
      ObjCInterfaceDecl *IFace = getCurMethodDecl()->getClassInterface();
      ObjCInterfaceDecl *ClassDeclared;
      if (ObjCIvarDecl *IV = IFace->lookupInstanceVariable(II, ClassDeclared)) {
        // Check if referencing a field with __attribute__((deprecated)).
        if (DiagnoseUseOfDecl(IV, Loc))
          return ExprError();
        
        // If we're referencing an invalid decl, just return this as a silent
        // error node.  The error diagnostic was already emitted on the decl.
        if (IV->isInvalidDecl())
          return ExprError();
        
        bool IsClsMethod = getCurMethodDecl()->isClassMethod();
        // If a class method attemps to use a free standing ivar, this is
        // an error.
        if (IsClsMethod && D && !D->isDefinedOutsideFunctionOrMethod())
           return ExprError(Diag(Loc, diag::error_ivar_use_in_class_method)
                           << IV->getDeclName());
        // If a class method uses a global variable, even if an ivar with
        // same name exists, use the global.
        if (!IsClsMethod) {
          if (IV->getAccessControl() == ObjCIvarDecl::Private &&
              ClassDeclared != IFace)
           Diag(Loc, diag::error_private_ivar_access) << IV->getDeclName();
          // FIXME: This should use a new expr for a direct reference, don't
          // turn this into Self->ivar, just return a BareIVarExpr or something.
          IdentifierInfo &II = Context.Idents.get("self");
          OwningExprResult SelfExpr = ActOnIdentifierExpr(S, SourceLocation(),
                                                          II, false);
          MarkDeclarationReferenced(Loc, IV);
          return Owned(new (Context) 
                       ObjCIvarRefExpr(IV, IV->getType(), Loc, 
                                       SelfExpr.takeAs<Expr>(), true, true));
        }
      }
    } else if (getCurMethodDecl()->isInstanceMethod()) {
      // We should warn if a local variable hides an ivar.
      ObjCInterfaceDecl *IFace = getCurMethodDecl()->getClassInterface();
      ObjCInterfaceDecl *ClassDeclared;
      if (ObjCIvarDecl *IV = IFace->lookupInstanceVariable(II, ClassDeclared)) {
        if (IV->getAccessControl() != ObjCIvarDecl::Private ||
            IFace == ClassDeclared)
          Diag(Loc, diag::warn_ivar_use_hidden) << IV->getDeclName();
      }
    }
    // Needed to implement property "super.method" notation.
    if (D == 0 && II->isStr("super")) {
      QualType T;
      
      if (getCurMethodDecl()->isInstanceMethod())
        T = Context.getObjCObjectPointerType(Context.getObjCInterfaceType(
                                      getCurMethodDecl()->getClassInterface()));
      else
        T = Context.getObjCClassType();
      return Owned(new (Context) ObjCSuperExpr(Loc, T));
    }
  }

  // Determine whether this name might be a candidate for
  // argument-dependent lookup.
  bool ADL = getLangOptions().CPlusPlus && (!SS || !SS->isSet()) && 
             HasTrailingLParen;

  if (ADL && D == 0) {
    // We've seen something of the form
    //
    //   identifier(
    //
    // and we did not find any entity by the name
    // "identifier". However, this identifier is still subject to
    // argument-dependent lookup, so keep track of the name.
    return Owned(new (Context) UnresolvedFunctionNameExpr(Name,
                                                          Context.OverloadTy,
                                                          Loc));
  }

  if (D == 0) {
    // Otherwise, this could be an implicitly declared function reference (legal
    // in C90, extension in C99).
    if (HasTrailingLParen && II &&
        !getLangOptions().CPlusPlus) // Not in C++.
      D = ImplicitlyDefineFunction(Loc, *II, S);
    else {
      // If this name wasn't predeclared and if this is not a function call,
      // diagnose the problem.
      if (SS && !SS->isEmpty())
        return ExprError(Diag(Loc, diag::err_typecheck_no_member)
          << Name << SS->getRange());
      else if (Name.getNameKind() == DeclarationName::CXXOperatorName ||
               Name.getNameKind() == DeclarationName::CXXConversionFunctionName)
        return ExprError(Diag(Loc, diag::err_undeclared_use)
          << Name.getAsString());
      else
        return ExprError(Diag(Loc, diag::err_undeclared_var_use) << Name);
    }
  }
  
  if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
    // Warn about constructs like:
    //   if (void *X = foo()) { ... } else { X }.
    // In the else block, the pointer is always false.
    
    // FIXME: In a template instantiation, we don't have scope
    // information to check this property.
    if (Var->isDeclaredInCondition() && Var->getType()->isScalarType()) {
      Scope *CheckS = S;
      while (CheckS) {
        if (CheckS->isWithinElse() && 
            CheckS->getControlParent()->isDeclScope(DeclPtrTy::make(Var))) {
          if (Var->getType()->isBooleanType())
            ExprError(Diag(Loc, diag::warn_value_always_false)
                      << Var->getDeclName());
          else
            ExprError(Diag(Loc, diag::warn_value_always_zero)
                      << Var->getDeclName());
          break;
        }
        
        // Move up one more control parent to check again.
        CheckS = CheckS->getControlParent();
        if (CheckS)
          CheckS = CheckS->getParent();
      }
    }
  } else if (FunctionDecl *Func = dyn_cast<FunctionDecl>(D)) {
    if (!getLangOptions().CPlusPlus && !Func->hasPrototype()) {
      // C99 DR 316 says that, if a function type comes from a
      // function definition (without a prototype), that type is only
      // used for checking compatibility. Therefore, when referencing
      // the function, we pretend that we don't have the full function
      // type.
      if (DiagnoseUseOfDecl(Func, Loc))
        return ExprError();

      QualType T = Func->getType();
      QualType NoProtoType = T;
      if (const FunctionProtoType *Proto = T->getAsFunctionProtoType())
        NoProtoType = Context.getFunctionNoProtoType(Proto->getResultType());
      return BuildDeclRefExpr(Func, NoProtoType, Loc, false, false, SS);
    }
  }
  
  return BuildDeclarationNameExpr(Loc, D, HasTrailingLParen, SS, isAddressOfOperand);
}
/// \brief Cast member's object to its own class if necessary.
bool
Sema::PerformObjectMemberConversion(Expr *&From, NamedDecl *Member) {
  if (FieldDecl *FD = dyn_cast<FieldDecl>(Member))
    if (CXXRecordDecl *RD = 
        dyn_cast<CXXRecordDecl>(FD->getDeclContext())) {
      QualType DestType = 
        Context.getCanonicalType(Context.getTypeDeclType(RD));
      if (DestType->isDependentType() || From->getType()->isDependentType())
        return false;
      QualType FromRecordType = From->getType();
      QualType DestRecordType = DestType;
      if (FromRecordType->getAs<PointerType>()) {
        DestType = Context.getPointerType(DestType);
        FromRecordType = FromRecordType->getPointeeType();
      }
      if (!Context.hasSameUnqualifiedType(FromRecordType, DestRecordType) &&
          CheckDerivedToBaseConversion(FromRecordType,
                                       DestRecordType,
                                       From->getSourceRange().getBegin(),
                                       From->getSourceRange()))
        return true;
      ImpCastExprToType(From, DestType, CastExpr::CK_DerivedToBase,
                        /*isLvalue=*/true);
    }
  return false;
}

/// \brief Complete semantic analysis for a reference to the given declaration.
Sema::OwningExprResult
Sema::BuildDeclarationNameExpr(SourceLocation Loc, NamedDecl *D,
                               bool HasTrailingLParen,
                               const CXXScopeSpec *SS, 
                               bool isAddressOfOperand) {
  assert(D && "Cannot refer to a NULL declaration");
  DeclarationName Name = D->getDeclName();
  
  // If this is an expression of the form &Class::member, don't build an
  // implicit member ref, because we want a pointer to the member in general,
  // not any specific instance's member.
  if (isAddressOfOperand && SS && !SS->isEmpty() && !HasTrailingLParen) {
    DeclContext *DC = computeDeclContext(*SS);
    if (D && isa<CXXRecordDecl>(DC)) {
      QualType DType;
      if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
        DType = FD->getType().getNonReferenceType();
      } else if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
        DType = Method->getType();
      } else if (isa<OverloadedFunctionDecl>(D)) {
        DType = Context.OverloadTy;
      }
      // Could be an inner type. That's diagnosed below, so ignore it here.
      if (!DType.isNull()) {
        // The pointer is type- and value-dependent if it points into something
        // dependent.
        bool Dependent = DC->isDependentContext();
        return BuildDeclRefExpr(D, DType, Loc, Dependent, Dependent, SS);
      }
    }
  }

  // We may have found a field within an anonymous union or struct
  // (C++ [class.union]).
  if (FieldDecl *FD = dyn_cast<FieldDecl>(D))
    if (cast<RecordDecl>(FD->getDeclContext())->isAnonymousStructOrUnion())
      return BuildAnonymousStructUnionMemberReference(Loc, FD);

  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext)) {
    if (!MD->isStatic()) {
      // C++ [class.mfct.nonstatic]p2: 
      //   [...] if name lookup (3.4.1) resolves the name in the
      //   id-expression to a nonstatic nontype member of class X or of
      //   a base class of X, the id-expression is transformed into a
      //   class member access expression (5.2.5) using (*this) (9.3.2)
      //   as the postfix-expression to the left of the '.' operator.
      DeclContext *Ctx = 0;
      QualType MemberType;
      if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
        Ctx = FD->getDeclContext();
        MemberType = FD->getType();

        if (const ReferenceType *RefType = MemberType->getAs<ReferenceType>())
          MemberType = RefType->getPointeeType();
        else if (!FD->isMutable()) {
          unsigned combinedQualifiers 
            = MemberType.getCVRQualifiers() | MD->getTypeQualifiers();
          MemberType = MemberType.getQualifiedType(combinedQualifiers);
        }
      } else if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
        if (!Method->isStatic()) {
          Ctx = Method->getParent();
          MemberType = Method->getType();
        }
      } else if (FunctionTemplateDecl *FunTmpl 
                   = dyn_cast<FunctionTemplateDecl>(D)) {
        if (CXXMethodDecl *Method 
              = dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())) {
          if (!Method->isStatic()) {          
            Ctx = Method->getParent();
            MemberType = Context.OverloadTy;
          }
        }
      } else if (OverloadedFunctionDecl *Ovl 
                   = dyn_cast<OverloadedFunctionDecl>(D)) {
        // FIXME: We need an abstraction for iterating over one or more function
        // templates or functions. This code is far too repetitive!
        for (OverloadedFunctionDecl::function_iterator 
               Func = Ovl->function_begin(),
               FuncEnd = Ovl->function_end();
             Func != FuncEnd; ++Func) {
          CXXMethodDecl *DMethod = 0;
          if (FunctionTemplateDecl *FunTmpl 
                = dyn_cast<FunctionTemplateDecl>(*Func))
            DMethod = dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
          else
            DMethod = dyn_cast<CXXMethodDecl>(*Func);

          if (DMethod && !DMethod->isStatic()) {
            Ctx = DMethod->getDeclContext();
            MemberType = Context.OverloadTy;
            break;
          }
        }
      }

      if (Ctx && Ctx->isRecord()) {
        QualType CtxType = Context.getTagDeclType(cast<CXXRecordDecl>(Ctx));
        QualType ThisType = Context.getTagDeclType(MD->getParent());
        if ((Context.getCanonicalType(CtxType) 
               == Context.getCanonicalType(ThisType)) ||
            IsDerivedFrom(ThisType, CtxType)) {
          // Build the implicit member access expression.
          Expr *This = new (Context) CXXThisExpr(SourceLocation(),
                                                 MD->getThisType(Context));
          MarkDeclarationReferenced(Loc, D);
          if (PerformObjectMemberConversion(This, D))
            return ExprError();
          if (DiagnoseUseOfDecl(D, Loc))
            return ExprError();
          return Owned(new (Context) MemberExpr(This, true, D,
                                                Loc, MemberType));
        }
      }
    }
  }

  if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
    if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext)) {
      if (MD->isStatic())
        // "invalid use of member 'x' in static member function"
        return ExprError(Diag(Loc,diag::err_invalid_member_use_in_static_method)
          << FD->getDeclName());
    }

    // Any other ways we could have found the field in a well-formed
    // program would have been turned into implicit member expressions
    // above.
    return ExprError(Diag(Loc, diag::err_invalid_non_static_member_use)
      << FD->getDeclName());
  }

  if (isa<TypedefDecl>(D))
    return ExprError(Diag(Loc, diag::err_unexpected_typedef) << Name);
  if (isa<ObjCInterfaceDecl>(D))
    return ExprError(Diag(Loc, diag::err_unexpected_interface) << Name);
  if (isa<NamespaceDecl>(D))
    return ExprError(Diag(Loc, diag::err_unexpected_namespace) << Name);

  // Make the DeclRefExpr or BlockDeclRefExpr for the decl.
  if (OverloadedFunctionDecl *Ovl = dyn_cast<OverloadedFunctionDecl>(D))
    return BuildDeclRefExpr(Ovl, Context.OverloadTy, Loc,
                           false, false, SS);
  else if (TemplateDecl *Template = dyn_cast<TemplateDecl>(D))
    return BuildDeclRefExpr(Template, Context.OverloadTy, Loc,
                            false, false, SS);
  ValueDecl *VD = cast<ValueDecl>(D);

  // Check whether this declaration can be used. Note that we suppress
  // this check when we're going to perform argument-dependent lookup
  // on this function name, because this might not be the function
  // that overload resolution actually selects.
  bool ADL = getLangOptions().CPlusPlus && (!SS || !SS->isSet()) && 
             HasTrailingLParen;
  if (!(ADL && isa<FunctionDecl>(VD)) && DiagnoseUseOfDecl(VD, Loc))
    return ExprError();

  // Only create DeclRefExpr's for valid Decl's.
  if (VD->isInvalidDecl())
    return ExprError();

  // If the identifier reference is inside a block, and it refers to a value
  // that is outside the block, create a BlockDeclRefExpr instead of a
  // DeclRefExpr.  This ensures the value is treated as a copy-in snapshot when
  // the block is formed.
  //
  // We do not do this for things like enum constants, global variables, etc,
  // as they do not get snapshotted.
  //
  if (CurBlock && ShouldSnapshotBlockValueReference(CurBlock, VD)) {
    MarkDeclarationReferenced(Loc, VD);
    QualType ExprTy = VD->getType().getNonReferenceType();
    // The BlocksAttr indicates the variable is bound by-reference.
    if (VD->getAttr<BlocksAttr>())
      return Owned(new (Context) BlockDeclRefExpr(VD, ExprTy, Loc, true));
    // This is to record that a 'const' was actually synthesize and added.
    bool constAdded = !ExprTy.isConstQualified();
    // Variable will be bound by-copy, make it const within the closure.
    
    ExprTy.addConst();
    return Owned(new (Context) BlockDeclRefExpr(VD, ExprTy, Loc, false, 
                                                constAdded));
  }
  // If this reference is not in a block or if the referenced variable is
  // within the block, create a normal DeclRefExpr.

  bool TypeDependent = false;
  bool ValueDependent = false;
  if (getLangOptions().CPlusPlus) {
    // C++ [temp.dep.expr]p3:
    //   An id-expression is type-dependent if it contains:   
    //     - an identifier that was declared with a dependent type,
    if (VD->getType()->isDependentType())
      TypeDependent = true;
    //     - FIXME: a template-id that is dependent,
    //     - a conversion-function-id that specifies a dependent type,
    else if (Name.getNameKind() == DeclarationName::CXXConversionFunctionName &&
             Name.getCXXNameType()->isDependentType())
      TypeDependent = true;
    //     - a nested-name-specifier that contains a class-name that
    //       names a dependent type.
    else if (SS && !SS->isEmpty()) {
      for (DeclContext *DC = computeDeclContext(*SS);
           DC; DC = DC->getParent()) {
        // FIXME: could stop early at namespace scope.
        if (DC->isRecord()) {
          CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
          if (Context.getTypeDeclType(Record)->isDependentType()) {
            TypeDependent = true;
            break;
          }
        }
      }
    }

    // C++ [temp.dep.constexpr]p2:
    //
    //   An identifier is value-dependent if it is:
    //     - a name declared with a dependent type,
    if (TypeDependent)
      ValueDependent = true;
    //     - the name of a non-type template parameter,
    else if (isa<NonTypeTemplateParmDecl>(VD))
      ValueDependent = true;
    //    - a constant with integral or enumeration type and is
    //      initialized with an expression that is value-dependent
    else if (const VarDecl *Dcl = dyn_cast<VarDecl>(VD)) {
      if (Dcl->getType().getCVRQualifiers() == QualType::Const &&
          Dcl->getInit()) {
        ValueDependent = Dcl->getInit()->isValueDependent();
      }
    }
  }

  return BuildDeclRefExpr(VD, VD->getType().getNonReferenceType(), Loc,
                          TypeDependent, ValueDependent, SS);
}

Sema::OwningExprResult Sema::ActOnPredefinedExpr(SourceLocation Loc,
                                                 tok::TokenKind Kind) {
  PredefinedExpr::IdentType IT;

  switch (Kind) {
  default: assert(0 && "Unknown simple primary expr!");
  case tok::kw___func__: IT = PredefinedExpr::Func; break; // [C99 6.4.2.2]
  case tok::kw___FUNCTION__: IT = PredefinedExpr::Function; break;
  case tok::kw___PRETTY_FUNCTION__: IT = PredefinedExpr::PrettyFunction; break;
  }

  // Pre-defined identifiers are of type char[x], where x is the length of the
  // string.
  unsigned Length;
  if (FunctionDecl *FD = getCurFunctionDecl())
    Length = FD->getIdentifier()->getLength();
  else if (ObjCMethodDecl *MD = getCurMethodDecl())
    Length = MD->getSynthesizedMethodSize();
  else {
    Diag(Loc, diag::ext_predef_outside_function);
    // __PRETTY_FUNCTION__ -> "top level", the others produce an empty string.
    Length = IT == PredefinedExpr::PrettyFunction ? strlen("top level") : 0;
  }


  llvm::APInt LengthI(32, Length + 1);
  QualType ResTy = Context.CharTy.getQualifiedType(QualType::Const);
  ResTy = Context.getConstantArrayType(ResTy, LengthI, ArrayType::Normal, 0);
  return Owned(new (Context) PredefinedExpr(Loc, ResTy, IT));
}

Sema::OwningExprResult Sema::ActOnCharacterConstant(const Token &Tok) {
  llvm::SmallString<16> CharBuffer;
  CharBuffer.resize(Tok.getLength());
  const char *ThisTokBegin = &CharBuffer[0];
  unsigned ActualLength = PP.getSpelling(Tok, ThisTokBegin);

  CharLiteralParser Literal(ThisTokBegin, ThisTokBegin+ActualLength,
                            Tok.getLocation(), PP);
  if (Literal.hadError())
    return ExprError();

  QualType type = getLangOptions().CPlusPlus ? Context.CharTy : Context.IntTy;

  return Owned(new (Context) CharacterLiteral(Literal.getValue(),
                                              Literal.isWide(),
                                              type, Tok.getLocation()));
}

Action::OwningExprResult Sema::ActOnNumericConstant(const Token &Tok) {
  // Fast path for a single digit (which is quite common).  A single digit
  // cannot have a trigraph, escaped newline, radix prefix, or type suffix.
  if (Tok.getLength() == 1) {
    const char Val = PP.getSpellingOfSingleCharacterNumericConstant(Tok);
    unsigned IntSize = Context.Target.getIntWidth();
    return Owned(new (Context) IntegerLiteral(llvm::APInt(IntSize, Val-'0'),
                    Context.IntTy, Tok.getLocation()));
  }

  llvm::SmallString<512> IntegerBuffer;
  // Add padding so that NumericLiteralParser can overread by one character.
  IntegerBuffer.resize(Tok.getLength()+1);
  const char *ThisTokBegin = &IntegerBuffer[0];

  // Get the spelling of the token, which eliminates trigraphs, etc.
  unsigned ActualLength = PP.getSpelling(Tok, ThisTokBegin);

  NumericLiteralParser Literal(ThisTokBegin, ThisTokBegin+ActualLength, 
                               Tok.getLocation(), PP);
  if (Literal.hadError)
    return ExprError();

  Expr *Res;

  if (Literal.isFloatingLiteral()) {
    QualType Ty;
    if (Literal.isFloat)
      Ty = Context.FloatTy;
    else if (!Literal.isLong)
      Ty = Context.DoubleTy;
    else
      Ty = Context.LongDoubleTy;

    const llvm::fltSemantics &Format = Context.getFloatTypeSemantics(Ty);

    // isExact will be set by GetFloatValue().
    bool isExact = false;
    llvm::APFloat Val = Literal.GetFloatValue(Format, &isExact);
    Res = new (Context) FloatingLiteral(Val, isExact, Ty, Tok.getLocation());

  } else if (!Literal.isIntegerLiteral()) {
    return ExprError();
  } else {
    QualType Ty;

    // long long is a C99 feature.
    if (!getLangOptions().C99 && !getLangOptions().CPlusPlus0x &&
        Literal.isLongLong)
      Diag(Tok.getLocation(), diag::ext_longlong);

    // Get the value in the widest-possible width.
    llvm::APInt ResultVal(Context.Target.getIntMaxTWidth(), 0);

    if (Literal.GetIntegerValue(ResultVal)) {
      // If this value didn't fit into uintmax_t, warn and force to ull.
      Diag(Tok.getLocation(), diag::warn_integer_too_large);
      Ty = Context.UnsignedLongLongTy;
      assert(Context.getTypeSize(Ty) == ResultVal.getBitWidth() &&
             "long long is not intmax_t?");
    } else {
      // If this value fits into a ULL, try to figure out what else it fits into
      // according to the rules of C99 6.4.4.1p5.

      // Octal, Hexadecimal, and integers with a U suffix are allowed to
      // be an unsigned int.
      bool AllowUnsigned = Literal.isUnsigned || Literal.getRadix() != 10;

      // Check from smallest to largest, picking the smallest type we can.
      unsigned Width = 0;
      if (!Literal.isLong && !Literal.isLongLong) {
        // Are int/unsigned possibilities?
        unsigned IntSize = Context.Target.getIntWidth();

        // Does it fit in a unsigned int?
        if (ResultVal.isIntN(IntSize)) {
          // Does it fit in a signed int?
          if (!Literal.isUnsigned && ResultVal[IntSize-1] == 0)
            Ty = Context.IntTy;
          else if (AllowUnsigned)
            Ty = Context.UnsignedIntTy;
          Width = IntSize;
        }
      }

      // Are long/unsigned long possibilities?
      if (Ty.isNull() && !Literal.isLongLong) {
        unsigned LongSize = Context.Target.getLongWidth();

        // Does it fit in a unsigned long?
        if (ResultVal.isIntN(LongSize)) {
          // Does it fit in a signed long?
          if (!Literal.isUnsigned && ResultVal[LongSize-1] == 0)
            Ty = Context.LongTy;
          else if (AllowUnsigned)
            Ty = Context.UnsignedLongTy;
          Width = LongSize;
        }
      }

      // Finally, check long long if needed.
      if (Ty.isNull()) {
        unsigned LongLongSize = Context.Target.getLongLongWidth();

        // Does it fit in a unsigned long long?
        if (ResultVal.isIntN(LongLongSize)) {
          // Does it fit in a signed long long?
          if (!Literal.isUnsigned && ResultVal[LongLongSize-1] == 0)
            Ty = Context.LongLongTy;
          else if (AllowUnsigned)
            Ty = Context.UnsignedLongLongTy;
          Width = LongLongSize;
        }
      }

      // If we still couldn't decide a type, we probably have something that
      // does not fit in a signed long long, but has no U suffix.
      if (Ty.isNull()) {
        Diag(Tok.getLocation(), diag::warn_integer_too_large_for_signed);
        Ty = Context.UnsignedLongLongTy;
        Width = Context.Target.getLongLongWidth();
      }

      if (ResultVal.getBitWidth() != Width)
        ResultVal.trunc(Width);
    }
    Res = new (Context) IntegerLiteral(ResultVal, Ty, Tok.getLocation());
  }

  // If this is an imaginary literal, create the ImaginaryLiteral wrapper.
  if (Literal.isImaginary)
    Res = new (Context) ImaginaryLiteral(Res, 
                                        Context.getComplexType(Res->getType()));

  return Owned(Res);
}

Action::OwningExprResult Sema::ActOnParenExpr(SourceLocation L,
                                              SourceLocation R, ExprArg Val) {
  Expr *E = Val.takeAs<Expr>();
  assert((E != 0) && "ActOnParenExpr() missing expr");
  return Owned(new (Context) ParenExpr(L, R, E));
}

/// The UsualUnaryConversions() function is *not* called by this routine.
/// See C99 6.3.2.1p[2-4] for more details.
bool Sema::CheckSizeOfAlignOfOperand(QualType exprType,
                                     SourceLocation OpLoc,
                                     const SourceRange &ExprRange,
                                     bool isSizeof) {
  if (exprType->isDependentType())
    return false;

  // C99 6.5.3.4p1:
  if (isa<FunctionType>(exprType)) {
    // alignof(function) is allowed as an extension.
    if (isSizeof)
      Diag(OpLoc, diag::ext_sizeof_function_type) << ExprRange;
    return false;
  }
  
  // Allow sizeof(void)/alignof(void) as an extension.
  if (exprType->isVoidType()) {
    Diag(OpLoc, diag::ext_sizeof_void_type)
      << (isSizeof ? "sizeof" : "__alignof") << ExprRange;
    return false;
  }
  
  if (RequireCompleteType(OpLoc, exprType,
                          isSizeof ? diag::err_sizeof_incomplete_type : 
                          diag::err_alignof_incomplete_type,
                          ExprRange))
    return true;
  
  // Reject sizeof(interface) and sizeof(interface<proto>) in 64-bit mode.
  if (LangOpts.ObjCNonFragileABI && exprType->isObjCInterfaceType()) {
    Diag(OpLoc, diag::err_sizeof_nonfragile_interface)
      << exprType << isSizeof << ExprRange;
    return true;
  }
    
  return false;
}

bool Sema::CheckAlignOfExpr(Expr *E, SourceLocation OpLoc,
                            const SourceRange &ExprRange) {
  E = E->IgnoreParens();

  // alignof decl is always ok. 
  if (isa<DeclRefExpr>(E))
    return false;

  // Cannot know anything else if the expression is dependent.
  if (E->isTypeDependent())
    return false;

  if (E->getBitField()) {
    Diag(OpLoc, diag::err_sizeof_alignof_bitfield) << 1 << ExprRange;
    return true;
  }

  // Alignment of a field access is always okay, so long as it isn't a
  // bit-field.
  if (MemberExpr *ME = dyn_cast<MemberExpr>(E))
    if (isa<FieldDecl>(ME->getMemberDecl()))
      return false;

  return CheckSizeOfAlignOfOperand(E->getType(), OpLoc, ExprRange, false);
}

/// \brief Build a sizeof or alignof expression given a type operand.
Action::OwningExprResult 
Sema::CreateSizeOfAlignOfExpr(QualType T, SourceLocation OpLoc, 
                              bool isSizeOf, SourceRange R) {
  if (T.isNull())
    return ExprError();

  if (!T->isDependentType() &&
      CheckSizeOfAlignOfOperand(T, OpLoc, R, isSizeOf))
    return ExprError();

  // C99 6.5.3.4p4: the type (an unsigned integer type) is size_t.
  return Owned(new (Context) SizeOfAlignOfExpr(isSizeOf, T,
                                               Context.getSizeType(), OpLoc,
                                               R.getEnd()));
}

/// \brief Build a sizeof or alignof expression given an expression
/// operand.
Action::OwningExprResult 
Sema::CreateSizeOfAlignOfExpr(Expr *E, SourceLocation OpLoc, 
                              bool isSizeOf, SourceRange R) {
  // Verify that the operand is valid.
  bool isInvalid = false;
  if (E->isTypeDependent()) {
    // Delay type-checking for type-dependent expressions.
  } else if (!isSizeOf) {
    isInvalid = CheckAlignOfExpr(E, OpLoc, R);
  } else if (E->getBitField()) {  // C99 6.5.3.4p1.
    Diag(OpLoc, diag::err_sizeof_alignof_bitfield) << 0;
    isInvalid = true;
  } else {
    isInvalid = CheckSizeOfAlignOfOperand(E->getType(), OpLoc, R, true);
  }

  if (isInvalid)
    return ExprError();

  // C99 6.5.3.4p4: the type (an unsigned integer type) is size_t.
  return Owned(new (Context) SizeOfAlignOfExpr(isSizeOf, E,
                                               Context.getSizeType(), OpLoc,
                                               R.getEnd()));
}

/// ActOnSizeOfAlignOfExpr - Handle @c sizeof(type) and @c sizeof @c expr and
/// the same for @c alignof and @c __alignof
/// Note that the ArgRange is invalid if isType is false.
Action::OwningExprResult
Sema::ActOnSizeOfAlignOfExpr(SourceLocation OpLoc, bool isSizeof, bool isType,
                             void *TyOrEx, const SourceRange &ArgRange) {
  // If error parsing type, ignore.
  if (TyOrEx == 0) return ExprError();

  if (isType) {
    // FIXME: Preserve type source info.
    QualType ArgTy = GetTypeFromParser(TyOrEx);
    return CreateSizeOfAlignOfExpr(ArgTy, OpLoc, isSizeof, ArgRange);
  } 

  // Get the end location.
  Expr *ArgEx = (Expr *)TyOrEx;
  Action::OwningExprResult Result
    = CreateSizeOfAlignOfExpr(ArgEx, OpLoc, isSizeof, ArgEx->getSourceRange());

  if (Result.isInvalid())
    DeleteExpr(ArgEx);

  return move(Result);
}

QualType Sema::CheckRealImagOperand(Expr *&V, SourceLocation Loc, bool isReal) {
  if (V->isTypeDependent())
    return Context.DependentTy;
  
  // These operators return the element type of a complex type.
  if (const ComplexType *CT = V->getType()->getAsComplexType())
    return CT->getElementType();
  
  // Otherwise they pass through real integer and floating point types here.
  if (V->getType()->isArithmeticType())
    return V->getType();
  
  // Reject anything else.
  Diag(Loc, diag::err_realimag_invalid_type) << V->getType()
    << (isReal ? "__real" : "__imag");
  return QualType();
}



Action::OwningExprResult
Sema::ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
                          tok::TokenKind Kind, ExprArg Input) {
  // Since this might be a postfix expression, get rid of ParenListExprs.
  Input = MaybeConvertParenListExprToParenExpr(S, move(Input));
  Expr *Arg = (Expr *)Input.get();

  UnaryOperator::Opcode Opc;
  switch (Kind) {
  default: assert(0 && "Unknown unary op!");
  case tok::plusplus:   Opc = UnaryOperator::PostInc; break;
  case tok::minusminus: Opc = UnaryOperator::PostDec; break;
  }

  if (getLangOptions().CPlusPlus &&
      (Arg->getType()->isRecordType() || Arg->getType()->isEnumeralType())) {
    // Which overloaded operator?
    OverloadedOperatorKind OverOp =
      (Opc == UnaryOperator::PostInc)? OO_PlusPlus : OO_MinusMinus;

    // C++ [over.inc]p1:
    //
    //     [...] If the function is a member function with one
    //     parameter (which shall be of type int) or a non-member
    //     function with two parameters (the second of which shall be
    //     of type int), it defines the postfix increment operator ++
    //     for objects of that type. When the postfix increment is
    //     called as a result of using the ++ operator, the int
    //     argument will have value zero.
    Expr *Args[2] = { 
      Arg, 
      new (Context) IntegerLiteral(llvm::APInt(Context.Target.getIntWidth(), 0, 
                          /*isSigned=*/true), Context.IntTy, SourceLocation())
    };

    // Build the candidate set for overloading
    OverloadCandidateSet CandidateSet;
    AddOperatorCandidates(OverOp, S, OpLoc, Args, 2, CandidateSet);

    // Perform overload resolution.
    OverloadCandidateSet::iterator Best;
    switch (BestViableFunction(CandidateSet, OpLoc, Best)) {
    case OR_Success: {
      // We found a built-in operator or an overloaded operator.
      FunctionDecl *FnDecl = Best->Function;

      if (FnDecl) {
        // We matched an overloaded operator. Build a call to that
        // operator.

        // Convert the arguments.
        if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
          if (PerformObjectArgumentInitialization(Arg, Method))
            return ExprError();
        } else {
          // Convert the arguments.
          if (PerformCopyInitialization(Arg,
                                        FnDecl->getParamDecl(0)->getType(),
                                        "passing"))
            return ExprError();
        }

        // Determine the result type
        QualType ResultTy
          = FnDecl->getType()->getAsFunctionType()->getResultType();
        ResultTy = ResultTy.getNonReferenceType();

        // Build the actual expression node.
        Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(),
                                                 SourceLocation());
        UsualUnaryConversions(FnExpr);

        Input.release();
        Args[0] = Arg;
        return Owned(new (Context) CXXOperatorCallExpr(Context, OverOp, FnExpr,
                                                       Args, 2, ResultTy, 
                                                       OpLoc));
      } else {
        // We matched a built-in operator. Convert the arguments, then
        // break out so that we will build the appropriate built-in
        // operator node.
        if (PerformCopyInitialization(Arg, Best->BuiltinTypes.ParamTypes[0],
                                      "passing"))
          return ExprError();

        break;
      }
    }

    case OR_No_Viable_Function:
      // No viable function; fall through to handling this as a
      // built-in operator, which will produce an error message for us.
      break;

    case OR_Ambiguous:
      Diag(OpLoc,  diag::err_ovl_ambiguous_oper)
          << UnaryOperator::getOpcodeStr(Opc)
          << Arg->getSourceRange();
      PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true);
      return ExprError();

    case OR_Deleted:
      Diag(OpLoc, diag::err_ovl_deleted_oper)
        << Best->Function->isDeleted()
        << UnaryOperator::getOpcodeStr(Opc)
        << Arg->getSourceRange();
      PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true);
      return ExprError();
    }

    // Either we found no viable overloaded operator or we matched a
    // built-in operator. In either case, fall through to trying to
    // build a built-in operation.
  }

  Input.release();
  Input = Arg;
  return CreateBuiltinUnaryOp(OpLoc, Opc, move(Input));
}

Action::OwningExprResult
Sema::ActOnArraySubscriptExpr(Scope *S, ExprArg Base, SourceLocation LLoc,
                              ExprArg Idx, SourceLocation RLoc) {
  // Since this might be a postfix expression, get rid of ParenListExprs.
  Base = MaybeConvertParenListExprToParenExpr(S, move(Base));

  Expr *LHSExp = static_cast<Expr*>(Base.get()),
       *RHSExp = static_cast<Expr*>(Idx.get());
  
  if (getLangOptions().CPlusPlus &&
      (LHSExp->isTypeDependent() || RHSExp->isTypeDependent())) {
    Base.release();
    Idx.release();
    return Owned(new (Context) ArraySubscriptExpr(LHSExp, RHSExp,
                                                  Context.DependentTy, RLoc));
  }

  if (getLangOptions().CPlusPlus && 
      (LHSExp->getType()->isRecordType() ||
       LHSExp->getType()->isEnumeralType() ||
       RHSExp->getType()->isRecordType() ||
       RHSExp->getType()->isEnumeralType())) {
    // Add the appropriate overloaded operators (C++ [over.match.oper]) 
    // to the candidate set.
    OverloadCandidateSet CandidateSet;
    Expr *Args[2] = { LHSExp, RHSExp };
    AddOperatorCandidates(OO_Subscript, S, LLoc, Args, 2, CandidateSet,
                          SourceRange(LLoc, RLoc));

    // Perform overload resolution.
    OverloadCandidateSet::iterator Best;
    switch (BestViableFunction(CandidateSet, LLoc, Best)) {
    case OR_Success: {
      // We found a built-in operator or an overloaded operator.
      FunctionDecl *FnDecl = Best->Function;

      if (FnDecl) {
        // We matched an overloaded operator. Build a call to that
        // operator.

        // Convert the arguments.
        if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
          if (PerformObjectArgumentInitialization(LHSExp, Method) ||
              PerformCopyInitialization(RHSExp, 
                                        FnDecl->getParamDecl(0)->getType(),
                                        "passing"))
            return ExprError();
        } else {
          // Convert the arguments.
          if (PerformCopyInitialization(LHSExp,
                                        FnDecl->getParamDecl(0)->getType(),
                                        "passing") ||
              PerformCopyInitialization(RHSExp,
                                        FnDecl->getParamDecl(1)->getType(),
                                        "passing"))
            return ExprError();
        }

        // Determine the result type
        QualType ResultTy
          = FnDecl->getType()->getAsFunctionType()->getResultType();
        ResultTy = ResultTy.getNonReferenceType();

        // Build the actual expression node.
        Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(),
                                                 SourceLocation());
        UsualUnaryConversions(FnExpr);

        Base.release();
        Idx.release();
        Args[0] = LHSExp;
        Args[1] = RHSExp;
        return Owned(new (Context) CXXOperatorCallExpr(Context, OO_Subscript,
                                                       FnExpr, Args, 2, 
                                                       ResultTy, LLoc));
      } else {
        // We matched a built-in operator. Convert the arguments, then
        // break out so that we will build the appropriate built-in
        // operator node.
        if (PerformCopyInitialization(LHSExp, Best->BuiltinTypes.ParamTypes[0],
                                      "passing") ||
            PerformCopyInitialization(RHSExp, Best->BuiltinTypes.ParamTypes[1],
                                      "passing"))
          return ExprError();

        break;
      }
    }

    case OR_No_Viable_Function:
      // No viable function; fall through to handling this as a
      // built-in operator, which will produce an error message for us.
      break;

    case OR_Ambiguous:
      Diag(LLoc,  diag::err_ovl_ambiguous_oper)
          << "[]"
          << LHSExp->getSourceRange() << RHSExp->getSourceRange();
      PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true);
      return ExprError();

    case OR_Deleted:
      Diag(LLoc, diag::err_ovl_deleted_oper)
        << Best->Function->isDeleted()
        << "[]"
        << LHSExp->getSourceRange() << RHSExp->getSourceRange();
      PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true);
      return ExprError();
    }

    // Either we found no viable overloaded operator or we matched a
    // built-in operator. In either case, fall through to trying to
    // build a built-in operation.
  }

  // Perform default conversions.
  DefaultFunctionArrayConversion(LHSExp);
  DefaultFunctionArrayConversion(RHSExp);

  QualType LHSTy = LHSExp->getType(), RHSTy = RHSExp->getType();

  // C99 6.5.2.1p2: the expression e1[e2] is by definition precisely equivalent
  // to the expression *((e1)+(e2)). This means the array "Base" may actually be
  // in the subscript position. As a result, we need to derive the array base
  // and index from the expression types.
  Expr *BaseExpr, *IndexExpr;
  QualType ResultType;
  if (LHSTy->isDependentType() || RHSTy->isDependentType()) {
    BaseExpr = LHSExp;
    IndexExpr = RHSExp;
    ResultType = Context.DependentTy;
  } else if (const PointerType *PTy = LHSTy->getAs<PointerType>()) {
    BaseExpr = LHSExp;
    IndexExpr = RHSExp;
    ResultType = PTy->getPointeeType();
  } else if (const PointerType *PTy = RHSTy->getAs<PointerType>()) {
     // Handle the uncommon case of "123[Ptr]".
    BaseExpr = RHSExp;
    IndexExpr = LHSExp;
    ResultType = PTy->getPointeeType();
  } else if (const ObjCObjectPointerType *PTy = 
               LHSTy->getAsObjCObjectPointerType()) {
    BaseExpr = LHSExp;
    IndexExpr = RHSExp;
    ResultType = PTy->getPointeeType();
  } else if (const ObjCObjectPointerType *PTy = 
               RHSTy->getAsObjCObjectPointerType()) {
     // Handle the uncommon case of "123[Ptr]".
    BaseExpr = RHSExp;
    IndexExpr = LHSExp;
    ResultType = PTy->getPointeeType();
  } else if (const VectorType *VTy = LHSTy->getAsVectorType()) {
    BaseExpr = LHSExp;    // vectors: V[123]
    IndexExpr = RHSExp;

    // FIXME: need to deal with const...
    ResultType = VTy->getElementType();
  } else if (LHSTy->isArrayType()) {
    // If we see an array that wasn't promoted by
    // DefaultFunctionArrayConversion, it must be an array that
    // wasn't promoted because of the C90 rule that doesn't
    // allow promoting non-lvalue arrays.  Warn, then
    // force the promotion here.
    Diag(LHSExp->getLocStart(), diag::ext_subscript_non_lvalue) <<
        LHSExp->getSourceRange();
    ImpCastExprToType(LHSExp, Context.getArrayDecayedType(LHSTy));
    LHSTy = LHSExp->getType();

    BaseExpr = LHSExp;
    IndexExpr = RHSExp;
    ResultType = LHSTy->getAs<PointerType>()->getPointeeType();
  } else if (RHSTy->isArrayType()) {
    // Same as previous, except for 123[f().a] case
    Diag(RHSExp->getLocStart(), diag::ext_subscript_non_lvalue) <<
        RHSExp->getSourceRange();
    ImpCastExprToType(RHSExp, Context.getArrayDecayedType(RHSTy));
    RHSTy = RHSExp->getType();

    BaseExpr = RHSExp;
    IndexExpr = LHSExp;
    ResultType = RHSTy->getAs<PointerType>()->getPointeeType();
  } else {
    return ExprError(Diag(LLoc, diag::err_typecheck_subscript_value)
       << LHSExp->getSourceRange() << RHSExp->getSourceRange());
  }
  // C99 6.5.2.1p1
  if (!(IndexExpr->getType()->isIntegerType() &&
        IndexExpr->getType()->isScalarType()) && !IndexExpr->isTypeDependent())
    return ExprError(Diag(LLoc, diag::err_typecheck_subscript_not_integer)
                     << IndexExpr->getSourceRange());

  // C99 6.5.2.1p1: "shall have type "pointer to *object* type". Similarly,
  // C++ [expr.sub]p1: The type "T" shall be a completely-defined object 
  // type. Note that Functions are not objects, and that (in C99 parlance) 
  // incomplete types are not object types.
  if (ResultType->isFunctionType()) {
    Diag(BaseExpr->getLocStart(), diag::err_subscript_function_type)
      << ResultType << BaseExpr->getSourceRange();
    return ExprError();
  }
  
  if (!ResultType->isDependentType() &&
      RequireCompleteType(LLoc, ResultType, diag::err_subscript_incomplete_type,
                          BaseExpr->getSourceRange()))
    return ExprError();
  
  // Diagnose bad cases where we step over interface counts.
  if (ResultType->isObjCInterfaceType() && LangOpts.ObjCNonFragileABI) {
    Diag(LLoc, diag::err_subscript_nonfragile_interface)
      << ResultType << BaseExpr->getSourceRange();
    return ExprError();
  }
  
  Base.release();
  Idx.release();
  return Owned(new (Context) ArraySubscriptExpr(LHSExp, RHSExp,
                                                ResultType, RLoc));
}

QualType Sema::
CheckExtVectorComponent(QualType baseType, SourceLocation OpLoc,
                        IdentifierInfo &CompName, SourceLocation CompLoc) {
  const ExtVectorType *vecType = baseType->getAsExtVectorType();

  // The vector accessor can't exceed the number of elements.
  const char *compStr = CompName.getName();

  // This flag determines whether or not the component is one of the four
  // special names that indicate a subset of exactly half the elements are
  // to be selected.
  bool HalvingSwizzle = false;

  // This flag determines whether or not CompName has an 's' char prefix,
  // indicating that it is a string of hex values to be used as vector indices.
  bool HexSwizzle = *compStr == 's' || *compStr == 'S';

  // Check that we've found one of the special components, or that the component
  // names must come from the same set.
  if (!strcmp(compStr, "hi") || !strcmp(compStr, "lo") ||
      !strcmp(compStr, "even") || !strcmp(compStr, "odd")) {
    HalvingSwizzle = true;
  } else if (vecType->getPointAccessorIdx(*compStr) != -1) {
    do
      compStr++;
    while (*compStr && vecType->getPointAccessorIdx(*compStr) != -1);
  } else if (HexSwizzle || vecType->getNumericAccessorIdx(*compStr) != -1) {
    do
      compStr++;
    while (*compStr && vecType->getNumericAccessorIdx(*compStr) != -1);
  }

  if (!HalvingSwizzle && *compStr) {
    // We didn't get to the end of the string. This means the component names
    // didn't come from the same set *or* we encountered an illegal name.
    Diag(OpLoc, diag::err_ext_vector_component_name_illegal)
      << std::string(compStr,compStr+1) << SourceRange(CompLoc);
    return QualType();
  }

  // Ensure no component accessor exceeds the width of the vector type it
  // operates on.
  if (!HalvingSwizzle) {
    compStr = CompName.getName();

    if (HexSwizzle)
      compStr++;

    while (*compStr) {
      if (!vecType->isAccessorWithinNumElements(*compStr++)) {
        Diag(OpLoc, diag::err_ext_vector_component_exceeds_length)
          << baseType << SourceRange(CompLoc);
        return QualType();
      }
    }
  }

  // If this is a halving swizzle, verify that the base type has an even
  // number of elements.
  if (HalvingSwizzle && (vecType->getNumElements() & 1U)) {
    Diag(OpLoc, diag::err_ext_vector_component_requires_even)
      << baseType << SourceRange(CompLoc);
    return QualType();
  }

  // The component accessor looks fine - now we need to compute the actual type.
  // The vector type is implied by the component accessor. For example,
  // vec4.b is a float, vec4.xy is a vec2, vec4.rgb is a vec3, etc.
  // vec4.s0 is a float, vec4.s23 is a vec3, etc.
  // vec4.hi, vec4.lo, vec4.e, and vec4.o all return vec2.
  unsigned CompSize = HalvingSwizzle ? vecType->getNumElements() / 2
                                     : CompName.getLength();
  if (HexSwizzle)
    CompSize--;

  if (CompSize == 1)
    return vecType->getElementType();

  QualType VT = Context.getExtVectorType(vecType->getElementType(), CompSize);
  // Now look up the TypeDefDecl from the vector type. Without this,
  // diagostics look bad. We want extended vector types to appear built-in.
  for (unsigned i = 0, E = ExtVectorDecls.size(); i != E; ++i) {
    if (ExtVectorDecls[i]->getUnderlyingType() == VT)
      return Context.getTypedefType(ExtVectorDecls[i]);
  }
  return VT; // should never get here (a typedef type should always be found).
}

static Decl *FindGetterNameDeclFromProtocolList(const ObjCProtocolDecl*PDecl,
                                                IdentifierInfo &Member,
                                                const Selector &Sel,
                                                ASTContext &Context) {
  
  if (ObjCPropertyDecl *PD = PDecl->FindPropertyDeclaration(&Member))
    return PD;
  if (ObjCMethodDecl *OMD = PDecl->getInstanceMethod(Sel))
    return OMD;
  
  for (ObjCProtocolDecl::protocol_iterator I = PDecl->protocol_begin(),
       E = PDecl->protocol_end(); I != E; ++I) {
    if (Decl *D = FindGetterNameDeclFromProtocolList(*I, Member, Sel, 
                                                     Context))
      return D;
  }
  return 0;
}

static Decl *FindGetterNameDecl(const ObjCObjectPointerType *QIdTy,
                                IdentifierInfo &Member,
                                const Selector &Sel,
                                ASTContext &Context) {
  // Check protocols on qualified interfaces.
  Decl *GDecl = 0;
  for (ObjCObjectPointerType::qual_iterator I = QIdTy->qual_begin(),
       E = QIdTy->qual_end(); I != E; ++I) {
    if (ObjCPropertyDecl *PD = (*I)->FindPropertyDeclaration(&Member)) {
      GDecl = PD;
      break;
    }
    // Also must look for a getter name which uses property syntax.
    if (ObjCMethodDecl *OMD = (*I)->getInstanceMethod(Sel)) {
      GDecl = OMD;
      break;
    }
  }
  if (!GDecl) {
    for (ObjCObjectPointerType::qual_iterator I = QIdTy->qual_begin(),
         E = QIdTy->qual_end(); I != E; ++I) {
      // Search in the protocol-qualifier list of current protocol.
      GDecl = FindGetterNameDeclFromProtocolList(*I, Member, Sel, Context);
      if (GDecl)
        return GDecl;
    }
  }
  return GDecl;
}

/// FindMethodInNestedImplementations - Look up a method in current and
/// all base class implementations.
///
ObjCMethodDecl *Sema::FindMethodInNestedImplementations(
                                              const ObjCInterfaceDecl *IFace,
                                              const Selector &Sel) {
  ObjCMethodDecl *Method = 0;
  if (ObjCImplementationDecl *ImpDecl = IFace->getImplementation())
    Method = ImpDecl->getInstanceMethod(Sel);
  
  if (!Method && IFace->getSuperClass())
    return FindMethodInNestedImplementations(IFace->getSuperClass(), Sel);
  return Method;
}

Action::OwningExprResult
Sema::ActOnMemberReferenceExpr(Scope *S, ExprArg Base, SourceLocation OpLoc,
                               tok::TokenKind OpKind, SourceLocation MemberLoc,
                               IdentifierInfo &Member,
                               DeclPtrTy ObjCImpDecl, const CXXScopeSpec *SS) {
  // FIXME: handle the CXXScopeSpec for proper lookup of qualified-ids
  if (SS && SS->isInvalid())
    return ExprError();

  // Since this might be a postfix expression, get rid of ParenListExprs.
  Base = MaybeConvertParenListExprToParenExpr(S, move(Base));

  Expr *BaseExpr = Base.takeAs<Expr>();
  assert(BaseExpr && "no record expression");
  
  // Perform default conversions.
  DefaultFunctionArrayConversion(BaseExpr);

  QualType BaseType = BaseExpr->getType();
  // If this is an Objective-C pseudo-builtin and a definition is provided then
  // use that.
  if (BaseType->isObjCIdType()) {
    // We have an 'id' type. Rather than fall through, we check if this
    // is a reference to 'isa'.
    if (BaseType != Context.ObjCIdRedefinitionType) {
      BaseType = Context.ObjCIdRedefinitionType;
      ImpCastExprToType(BaseExpr, BaseType);
    }
  } else if (BaseType->isObjCClassType() &&
      BaseType != Context.ObjCClassRedefinitionType) {
    BaseType = Context.ObjCClassRedefinitionType;
    ImpCastExprToType(BaseExpr, BaseType);
  }
  assert(!BaseType.isNull() && "no type for member expression");

  // Get the type being accessed in BaseType.  If this is an arrow, the BaseExpr
  // must have pointer type, and the accessed type is the pointee.
  if (OpKind == tok::arrow) {
    if (BaseType->isDependentType())
      return Owned(new (Context) CXXUnresolvedMemberExpr(Context,
                                                         BaseExpr, true, 
                                                         OpLoc, 
                                                     DeclarationName(&Member),
                                                         MemberLoc));
    else if (const PointerType *PT = BaseType->getAs<PointerType>())
      BaseType = PT->getPointeeType();
    else if (BaseType->isObjCObjectPointerType())
      ;
    else
      return ExprError(Diag(MemberLoc,
                            diag::err_typecheck_member_reference_arrow)
        << BaseType << BaseExpr->getSourceRange());
  } else {
    if (BaseType->isDependentType()) {
      // Require that the base type isn't a pointer type 
      // (so we'll report an error for)
      // T* t;
      // t.f;
      // 
      // In Obj-C++, however, the above expression is valid, since it could be
      // accessing the 'f' property if T is an Obj-C interface. The extra check
      // allows this, while still reporting an error if T is a struct pointer.
      const PointerType *PT = BaseType->getAs<PointerType>();

      if (!PT || (getLangOptions().ObjC1 && 
                  !PT->getPointeeType()->isRecordType()))
        return Owned(new (Context) CXXUnresolvedMemberExpr(Context,
                                                           BaseExpr, false, 
                                                           OpLoc, 
                                                     DeclarationName(&Member),
                                                           MemberLoc));
    }
  }

  // Handle field access to simple records.  This also handles access to fields
  // of the ObjC 'id' struct.
  if (const RecordType *RTy = BaseType->getAs<RecordType>()) {
    RecordDecl *RDecl = RTy->getDecl();
    if (RequireCompleteType(OpLoc, BaseType,
                               diag::err_typecheck_incomplete_tag,
                               BaseExpr->getSourceRange()))
      return ExprError();

    DeclContext *DC = RDecl;
    if (SS && SS->isSet()) {
      // If the member name was a qualified-id, look into the
      // nested-name-specifier.
      DC = computeDeclContext(*SS, false);
      
      // FIXME: If DC is not computable, we should build a 
      // CXXUnresolvedMemberExpr.
      assert(DC && "Cannot handle non-computable dependent contexts in lookup");
    }

    // The record definition is complete, now make sure the member is valid.
    LookupResult Result
      = LookupQualifiedName(DC, DeclarationName(&Member),  
                            LookupMemberName, false);

    if (SS && SS->isSet()) {
      QualType BaseTypeCanon 
        = Context.getCanonicalType(BaseType).getUnqualifiedType();
      QualType MemberTypeCanon 
        = Context.getCanonicalType(
            Context.getTypeDeclType(
                     dyn_cast<TypeDecl>(Result.getAsDecl()->getDeclContext())));

      if (BaseTypeCanon != MemberTypeCanon &&
          !IsDerivedFrom(BaseTypeCanon, MemberTypeCanon))
        return ExprError(Diag(SS->getBeginLoc(),
                              diag::err_not_direct_base_or_virtual)
                         << MemberTypeCanon << BaseTypeCanon);
    }

    if (!Result)
      return ExprError(Diag(MemberLoc, diag::err_typecheck_no_member)
               << &Member << BaseExpr->getSourceRange());
    if (Result.isAmbiguous()) {
      DiagnoseAmbiguousLookup(Result, DeclarationName(&Member),
                              MemberLoc, BaseExpr->getSourceRange());
      return ExprError();
    }
    
    NamedDecl *MemberDecl = Result;

    // If the decl being referenced had an error, return an error for this
    // sub-expr without emitting another error, in order to avoid cascading
    // error cases.
    if (MemberDecl->isInvalidDecl())
      return ExprError();

    // Check the use of this field
    if (DiagnoseUseOfDecl(MemberDecl, MemberLoc))
      return ExprError();

    if (FieldDecl *FD = dyn_cast<FieldDecl>(MemberDecl)) {
      // We may have found a field within an anonymous union or struct
      // (C++ [class.union]).
      if (cast<RecordDecl>(FD->getDeclContext())->isAnonymousStructOrUnion())
        return BuildAnonymousStructUnionMemberReference(MemberLoc, FD,
                                                        BaseExpr, OpLoc);

      // Figure out the type of the member; see C99 6.5.2.3p3, C++ [expr.ref]
      QualType MemberType = FD->getType();
      if (const ReferenceType *Ref = MemberType->getAs<ReferenceType>())
        MemberType = Ref->getPointeeType();
      else {
        unsigned BaseAddrSpace = BaseType.getAddressSpace();
        unsigned combinedQualifiers =
          MemberType.getCVRQualifiers() | BaseType.getCVRQualifiers();
        if (FD->isMutable())
          combinedQualifiers &= ~QualType::Const;
        MemberType = MemberType.getQualifiedType(combinedQualifiers);
        if (BaseAddrSpace != MemberType.getAddressSpace())
           MemberType = Context.getAddrSpaceQualType(MemberType, BaseAddrSpace);
      }

      MarkDeclarationReferenced(MemberLoc, FD);
      if (PerformObjectMemberConversion(BaseExpr, FD))
        return ExprError();
      return Owned(new (Context) MemberExpr(BaseExpr, OpKind == tok::arrow, FD,
                                            MemberLoc, MemberType));
    }
    
    if (VarDecl *Var = dyn_cast<VarDecl>(MemberDecl)) {
      MarkDeclarationReferenced(MemberLoc, MemberDecl);
      return Owned(new (Context) MemberExpr(BaseExpr, OpKind == tok::arrow,
                                            Var, MemberLoc,
                                         Var->getType().getNonReferenceType()));
    }
    if (FunctionDecl *MemberFn = dyn_cast<FunctionDecl>(MemberDecl)) {
      MarkDeclarationReferenced(MemberLoc, MemberDecl);
      return Owned(new (Context) MemberExpr(BaseExpr, OpKind == tok::arrow,
                                            MemberFn, MemberLoc,
                                            MemberFn->getType()));
    }
    if (FunctionTemplateDecl *FunTmpl 
          = dyn_cast<FunctionTemplateDecl>(MemberDecl)) {
      MarkDeclarationReferenced(MemberLoc, MemberDecl);
      return Owned(new (Context) MemberExpr(BaseExpr, OpKind == tok::arrow,
                                            FunTmpl, MemberLoc,
                                            Context.OverloadTy));
    }
    if (OverloadedFunctionDecl *Ovl
          = dyn_cast<OverloadedFunctionDecl>(MemberDecl))
      return Owned(new (Context) MemberExpr(BaseExpr, OpKind == tok::arrow, Ovl,
                                            MemberLoc, Context.OverloadTy));
    if (EnumConstantDecl *Enum = dyn_cast<EnumConstantDecl>(MemberDecl)) {
      MarkDeclarationReferenced(MemberLoc, MemberDecl);
      return Owned(new (Context) MemberExpr(BaseExpr, OpKind == tok::arrow,
                                            Enum, MemberLoc, Enum->getType()));
    }
    if (isa<TypeDecl>(MemberDecl))
      return ExprError(Diag(MemberLoc,diag::err_typecheck_member_reference_type)
        << DeclarationName(&Member) << int(OpKind == tok::arrow));

    // We found a declaration kind that we didn't expect. This is a
    // generic error message that tells the user that she can't refer
    // to this member with '.' or '->'.
    return ExprError(Diag(MemberLoc,
                          diag::err_typecheck_member_reference_unknown)
      << DeclarationName(&Member) << int(OpKind == tok::arrow));
  }

  // Handle properties on ObjC 'Class' types.
  if (OpKind == tok::period && BaseType->isObjCClassType()) {
    // Also must look for a getter name which uses property syntax.
    Selector Sel = PP.getSelectorTable().getNullarySelector(&Member);
    if (ObjCMethodDecl *MD = getCurMethodDecl()) {
      ObjCInterfaceDecl *IFace = MD->getClassInterface();
      ObjCMethodDecl *Getter;
      // FIXME: need to also look locally in the implementation.
      if ((Getter = IFace->lookupClassMethod(Sel))) {
        // Check the use of this method.
        if (DiagnoseUseOfDecl(Getter, MemberLoc))
          return ExprError();
      }
      // If we found a getter then this may be a valid dot-reference, we
      // will look for the matching setter, in case it is needed.
      Selector SetterSel = 
        SelectorTable::constructSetterName(PP.getIdentifierTable(), 
                                           PP.getSelectorTable(), &Member);
      ObjCMethodDecl *Setter = IFace->lookupClassMethod(SetterSel);
      if (!Setter) {
        // If this reference is in an @implementation, also check for 'private'
        // methods.
        Setter = FindMethodInNestedImplementations(IFace, SetterSel);
      }
      // Look through local category implementations associated with the class.
      if (!Setter)
        Setter = IFace->getCategoryClassMethod(SetterSel);

      if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
        return ExprError();

      if (Getter || Setter) {
        QualType PType;

        if (Getter)
          PType = Getter->getResultType();
        else
          // Get the expression type from Setter's incoming parameter.
          PType = (*(Setter->param_end() -1))->getType();
        // FIXME: we must check that the setter has property type.
        return Owned(new (Context) ObjCImplicitSetterGetterRefExpr(Getter, PType,
                                        Setter, MemberLoc, BaseExpr));
      }
      return ExprError(Diag(MemberLoc, diag::err_property_not_found)
        << &Member << BaseType);
    }
  }
  // Handle access to Objective-C instance variables, such as "Obj->ivar" and
  // (*Obj).ivar.
  if ((OpKind == tok::arrow && BaseType->isObjCObjectPointerType()) ||
      (OpKind == tok::period && BaseType->isObjCInterfaceType())) {
    const ObjCObjectPointerType *OPT = BaseType->getAsObjCObjectPointerType();
    const ObjCInterfaceType *IFaceT = 
      OPT ? OPT->getInterfaceType() : BaseType->getAsObjCInterfaceType();
    if (IFaceT) {
      ObjCInterfaceDecl *IDecl = IFaceT->getDecl();
      ObjCInterfaceDecl *ClassDeclared;
      ObjCIvarDecl *IV = IDecl->lookupInstanceVariable(&Member, ClassDeclared);
      
      if (IV) {
        // If the decl being referenced had an error, return an error for this
        // sub-expr without emitting another error, in order to avoid cascading
        // error cases.
        if (IV->isInvalidDecl())
          return ExprError();

        // Check whether we can reference this field.
        if (DiagnoseUseOfDecl(IV, MemberLoc))
          return ExprError();
        if (IV->getAccessControl() != ObjCIvarDecl::Public &&
            IV->getAccessControl() != ObjCIvarDecl::Package) {
          ObjCInterfaceDecl *ClassOfMethodDecl = 0;
          if (ObjCMethodDecl *MD = getCurMethodDecl())
            ClassOfMethodDecl =  MD->getClassInterface();
          else if (ObjCImpDecl && getCurFunctionDecl()) {
            // Case of a c-function declared inside an objc implementation.
            // FIXME: For a c-style function nested inside an objc implementation
            // class, there is no implementation context available, so we pass
            // down the context as argument to this routine. Ideally, this context
            // need be passed down in the AST node and somehow calculated from the
            // AST for a function decl.
            Decl *ImplDecl = ObjCImpDecl.getAs<Decl>();
            if (ObjCImplementationDecl *IMPD = 
                dyn_cast<ObjCImplementationDecl>(ImplDecl))
              ClassOfMethodDecl = IMPD->getClassInterface();
            else if (ObjCCategoryImplDecl* CatImplClass =
                        dyn_cast<ObjCCategoryImplDecl>(ImplDecl))
              ClassOfMethodDecl = CatImplClass->getClassInterface();
          }
          
          if (IV->getAccessControl() == ObjCIvarDecl::Private) { 
            if (ClassDeclared != IDecl || 
                ClassOfMethodDecl != ClassDeclared)
              Diag(MemberLoc, diag::error_private_ivar_access) 
                << IV->getDeclName();
          } else if (!IDecl->isSuperClassOf(ClassOfMethodDecl))
            // @protected
            Diag(MemberLoc, diag::error_protected_ivar_access) 
              << IV->getDeclName();
        }

        return Owned(new (Context) ObjCIvarRefExpr(IV, IV->getType(),
                                                   MemberLoc, BaseExpr,
                                                   OpKind == tok::arrow));
      }
      return ExprError(Diag(MemberLoc, diag::err_typecheck_member_reference_ivar)
                         << IDecl->getDeclName() << &Member
                         << BaseExpr->getSourceRange());
    }
  }
  // Handle properties on 'id' and qualified "id".
  if (OpKind == tok::period && (BaseType->isObjCIdType() || 
                                BaseType->isObjCQualifiedIdType())) {
    const ObjCObjectPointerType *QIdTy = BaseType->getAsObjCObjectPointerType();
    
    // Check protocols on qualified interfaces.
    Selector Sel = PP.getSelectorTable().getNullarySelector(&Member);
    if (Decl *PMDecl = FindGetterNameDecl(QIdTy, Member, Sel, Context)) {
      if (ObjCPropertyDecl *PD = dyn_cast<ObjCPropertyDecl>(PMDecl)) {
        // Check the use of this declaration
        if (DiagnoseUseOfDecl(PD, MemberLoc))
          return ExprError();
        
        return Owned(new (Context) ObjCPropertyRefExpr(PD, PD->getType(),
                                                       MemberLoc, BaseExpr));
      }
      if (ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(PMDecl)) {
        // Check the use of this method.
        if (DiagnoseUseOfDecl(OMD, MemberLoc))
          return ExprError();
        
        return Owned(new (Context) ObjCMessageExpr(BaseExpr, Sel,
                                                   OMD->getResultType(), 
                                                   OMD, OpLoc, MemberLoc, 
                                                   NULL, 0));
      }
    }

    return ExprError(Diag(MemberLoc, diag::err_property_not_found)
                       << &Member << BaseType);
  }
  // Handle Objective-C property access, which is "Obj.property" where Obj is a
  // pointer to a (potentially qualified) interface type.
  const ObjCObjectPointerType *OPT;
  if (OpKind == tok::period && 
      (OPT = BaseType->getAsObjCInterfacePointerType())) {
    const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
    ObjCInterfaceDecl *IFace = IFaceT->getDecl();
    
    // Search for a declared property first.
    if (ObjCPropertyDecl *PD = IFace->FindPropertyDeclaration(&Member)) {
      // Check whether we can reference this property.
      if (DiagnoseUseOfDecl(PD, MemberLoc))
        return ExprError();
      QualType ResTy = PD->getType();
      Selector Sel = PP.getSelectorTable().getNullarySelector(&Member);
      ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
      if (DiagnosePropertyAccessorMismatch(PD, Getter, MemberLoc))
        ResTy = Getter->getResultType();
      return Owned(new (Context) ObjCPropertyRefExpr(PD, ResTy,
                                                     MemberLoc, BaseExpr));
    }
    // Check protocols on qualified interfaces.
    for (ObjCObjectPointerType::qual_iterator I = OPT->qual_begin(),
         E = OPT->qual_end(); I != E; ++I)
      if (ObjCPropertyDecl *PD = (*I)->FindPropertyDeclaration(&Member)) {
        // Check whether we can reference this property.
        if (DiagnoseUseOfDecl(PD, MemberLoc))
          return ExprError();

        return Owned(new (Context) ObjCPropertyRefExpr(PD, PD->getType(),
                                                       MemberLoc, BaseExpr));
      }
    for (ObjCObjectPointerType::qual_iterator I = OPT->qual_begin(),
         E = OPT->qual_end(); I != E; ++I)
      if (ObjCPropertyDecl *PD = (*I)->FindPropertyDeclaration(&Member)) {
        // Check whether we can reference this property.
        if (DiagnoseUseOfDecl(PD, MemberLoc))
          return ExprError();

        return Owned(new (Context) ObjCPropertyRefExpr(PD, PD->getType(),
                                                       MemberLoc, BaseExpr));
      }
    // If that failed, look for an "implicit" property by seeing if the nullary
    // selector is implemented.

    // FIXME: The logic for looking up nullary and unary selectors should be
    // shared with the code in ActOnInstanceMessage.

    Selector Sel = PP.getSelectorTable().getNullarySelector(&Member);
    ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);

    // If this reference is in an @implementation, check for 'private' methods.
    if (!Getter)
      Getter = FindMethodInNestedImplementations(IFace, Sel);

    // Look through local category implementations associated with the class.
    if (!Getter)
      Getter = IFace->getCategoryInstanceMethod(Sel);
    if (Getter) {
      // Check if we can reference this property.
      if (DiagnoseUseOfDecl(Getter, MemberLoc))
        return ExprError();
    }
    // If we found a getter then this may be a valid dot-reference, we
    // will look for the matching setter, in case it is needed.
    Selector SetterSel = 
      SelectorTable::constructSetterName(PP.getIdentifierTable(), 
                                         PP.getSelectorTable(), &Member);
    ObjCMethodDecl *Setter = IFace->lookupInstanceMethod(SetterSel);
    if (!Setter) {
      // If this reference is in an @implementation, also check for 'private'
      // methods.
      Setter = FindMethodInNestedImplementations(IFace, SetterSel);
    }
    // Look through local category implementations associated with the class.
    if (!Setter)
      Setter = IFace->getCategoryInstanceMethod(SetterSel);

    if (Setter && DiagnoseUseOfDecl(Setter, MemberLoc))
      return ExprError();

    if (Getter || Setter) {
      QualType PType;

      if (Getter)
        PType = Getter->getResultType();
      else
        // Get the expression type from Setter's incoming parameter.
        PType = (*(Setter->param_end() -1))->getType();
      // FIXME: we must check that the setter has property type.
      return Owned(new (Context) ObjCImplicitSetterGetterRefExpr(Getter, PType,
                                      Setter, MemberLoc, BaseExpr));
    }
    return ExprError(Diag(MemberLoc, diag::err_property_not_found)
      << &Member << BaseType);
  }
  
  // Handle the following exceptional case (*Obj).isa.
  if (OpKind == tok::period && 
      BaseType->isSpecificBuiltinType(BuiltinType::ObjCId) &&
      Member.isStr("isa"))
    return Owned(new (Context) ObjCIsaExpr(BaseExpr, false, MemberLoc,
                                           Context.getObjCIdType()));

  // Handle 'field access' to vectors, such as 'V.xx'.
  if (BaseType->isExtVectorType()) {
    QualType ret = CheckExtVectorComponent(BaseType, OpLoc, Member, MemberLoc);
    if (ret.isNull())
      return ExprError();
    return Owned(new (Context) ExtVectorElementExpr(ret, BaseExpr, Member,
                                                    MemberLoc));
  }

  Diag(MemberLoc, diag::err_typecheck_member_reference_struct_union)
    << BaseType << BaseExpr->getSourceRange();

  // If the user is trying to apply -> or . to a function or function
  // pointer, it's probably because they forgot parentheses to call
  // the function. Suggest the addition of those parentheses.
  if (BaseType == Context.OverloadTy || 
      BaseType->isFunctionType() ||
      (BaseType->isPointerType() && 
       BaseType->getAs<PointerType>()->isFunctionType())) {
    SourceLocation Loc = PP.getLocForEndOfToken(BaseExpr->getLocEnd());
    Diag(Loc, diag::note_member_reference_needs_call)
      << CodeModificationHint::CreateInsertion(Loc, "()");
  }

  return ExprError();
}

/// ConvertArgumentsForCall - Converts the arguments specified in
/// Args/NumArgs to the parameter types of the function FDecl with
/// function prototype Proto. Call is the call expression itself, and
/// Fn is the function expression. For a C++ member function, this
/// routine does not attempt to convert the object argument. Returns
/// true if the call is ill-formed.
bool
Sema::ConvertArgumentsForCall(CallExpr *Call, Expr *Fn,
                              FunctionDecl *FDecl,
                              const FunctionProtoType *Proto,
                              Expr **Args, unsigned NumArgs,
                              SourceLocation RParenLoc) {
  // C99 6.5.2.2p7 - the arguments are implicitly converted, as if by
  // assignment, to the types of the corresponding parameter, ...
  unsigned NumArgsInProto = Proto->getNumArgs();
  unsigned NumArgsToCheck = NumArgs;
  bool Invalid = false;

  // If too few arguments are available (and we don't have default
  // arguments for the remaining parameters), don't make the call.
  if (NumArgs < NumArgsInProto) {
    if (!FDecl || NumArgs < FDecl->getMinRequiredArguments())
      return Diag(RParenLoc, diag::err_typecheck_call_too_few_args)
        << Fn->getType()->isBlockPointerType() << Fn->getSourceRange();
    // Use default arguments for missing arguments
    NumArgsToCheck = NumArgsInProto;
    Call->setNumArgs(Context, NumArgsInProto);
  }

  // If too many are passed and not variadic, error on the extras and drop
  // them.
  if (NumArgs > NumArgsInProto) {
    if (!Proto->isVariadic()) {
      Diag(Args[NumArgsInProto]->getLocStart(),
           diag::err_typecheck_call_too_many_args)
        << Fn->getType()->isBlockPointerType() << Fn->getSourceRange()
        << SourceRange(Args[NumArgsInProto]->getLocStart(),
                       Args[NumArgs-1]->getLocEnd());
      // This deletes the extra arguments.
      Call->setNumArgs(Context, NumArgsInProto);
      Invalid = true;
    }
    NumArgsToCheck = NumArgsInProto;
  }

  // Continue to check argument types (even if we have too few/many args).
  for (unsigned i = 0; i != NumArgsToCheck; i++) {
    QualType ProtoArgType = Proto->getArgType(i);

    Expr *Arg;
    if (i < NumArgs) {
      Arg = Args[i];

      if (RequireCompleteType(Arg->getSourceRange().getBegin(),
                              ProtoArgType,
                              diag::err_call_incomplete_argument,
                              Arg->getSourceRange()))
        return true;

      // Pass the argument.
      if (PerformCopyInitialization(Arg, ProtoArgType, "passing"))
        return true;
    } else {
      if (FDecl->getParamDecl(i)->hasUnparsedDefaultArg()) {
        Diag (Call->getSourceRange().getBegin(),
              diag::err_use_of_default_argument_to_function_declared_later) <<
        FDecl << cast<CXXRecordDecl>(FDecl->getDeclContext())->getDeclName();
        Diag(UnparsedDefaultArgLocs[FDecl->getParamDecl(i)], 
              diag::note_default_argument_declared_here);
      } else {
        Expr *DefaultExpr = FDecl->getParamDecl(i)->getDefaultArg();
        
        // If the default expression creates temporaries, we need to
        // push them to the current stack of expression temporaries so they'll
        // be properly destroyed.
        if (CXXExprWithTemporaries *E 
              = dyn_cast_or_null<CXXExprWithTemporaries>(DefaultExpr)) {
          assert(!E->shouldDestroyTemporaries() && 
                 "Can't destroy temporaries in a default argument expr!");
          for (unsigned I = 0, N = E->getNumTemporaries(); I != N; ++I)
            ExprTemporaries.push_back(E->getTemporary(I));
        }
      }
  
      // We already type-checked the argument, so we know it works.
      Arg = CXXDefaultArgExpr::Create(Context, FDecl->getParamDecl(i));
    }
    
    QualType ArgType = Arg->getType();

    Call->setArg(i, Arg);
  }

  // If this is a variadic call, handle args passed through "...".
  if (Proto->isVariadic()) {
    VariadicCallType CallType = VariadicFunction;
    if (Fn->getType()->isBlockPointerType())
      CallType = VariadicBlock; // Block
    else if (isa<MemberExpr>(Fn))
      CallType = VariadicMethod;

    // Promote the arguments (C99 6.5.2.2p7).
    for (unsigned i = NumArgsInProto; i != NumArgs; i++) {
      Expr *Arg = Args[i];
      Invalid |= DefaultVariadicArgumentPromotion(Arg, CallType);
      Call->setArg(i, Arg);
    }
  }

  return Invalid;
}

/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
/// This provides the location of the left/right parens and a list of comma
/// locations.
Action::OwningExprResult
Sema::ActOnCallExpr(Scope *S, ExprArg fn, SourceLocation LParenLoc,
                    MultiExprArg args,
                    SourceLocation *CommaLocs, SourceLocation RParenLoc) {
  unsigned NumArgs = args.size();

  // Since this might be a postfix expression, get rid of ParenListExprs.
  fn = MaybeConvertParenListExprToParenExpr(S, move(fn));
  
  Expr *Fn = fn.takeAs<Expr>();
  Expr **Args = reinterpret_cast<Expr**>(args.release());
  assert(Fn && "no function call expression");
  FunctionDecl *FDecl = NULL;
  NamedDecl *NDecl = NULL;
  DeclarationName UnqualifiedName;
  
  if (getLangOptions().CPlusPlus) {
    // Determine whether this is a dependent call inside a C++ template,
    // in which case we won't do any semantic analysis now.
    // FIXME: Will need to cache the results of name lookup (including ADL) in
    // Fn.
    bool Dependent = false;
    if (Fn->isTypeDependent())
      Dependent = true;
    else if (Expr::hasAnyTypeDependentArguments(Args, NumArgs))
      Dependent = true;

    if (Dependent)
      return Owned(new (Context) CallExpr(Context, Fn, Args, NumArgs,
                                          Context.DependentTy, RParenLoc));

    // Determine whether this is a call to an object (C++ [over.call.object]).
    if (Fn->getType()->isRecordType())
      return Owned(BuildCallToObjectOfClassType(S, Fn, LParenLoc, Args, NumArgs,
                                                CommaLocs, RParenLoc));

    // Determine whether this is a call to a member function.
    if (MemberExpr *MemExpr = dyn_cast<MemberExpr>(Fn->IgnoreParens())) {
      NamedDecl *MemDecl = MemExpr->getMemberDecl();
      if (isa<OverloadedFunctionDecl>(MemDecl) ||
          isa<CXXMethodDecl>(MemDecl) ||
          (isa<FunctionTemplateDecl>(MemDecl) &&
           isa<CXXMethodDecl>(
                cast<FunctionTemplateDecl>(MemDecl)->getTemplatedDecl())))
        return Owned(BuildCallToMemberFunction(S, Fn, LParenLoc, Args, NumArgs,
                                               CommaLocs, RParenLoc));
    }
  }

  // If we're directly calling a function, get the appropriate declaration.
  // Also, in C++, keep track of whether we should perform argument-dependent 
  // lookup and whether there were any explicitly-specified template arguments.
  Expr *FnExpr = Fn;
  bool ADL = true;
  bool HasExplicitTemplateArgs = 0;
  const TemplateArgument *ExplicitTemplateArgs = 0;
  unsigned NumExplicitTemplateArgs = 0;
  while (true) {
    if (ImplicitCastExpr *IcExpr = dyn_cast<ImplicitCastExpr>(FnExpr))
      FnExpr = IcExpr->getSubExpr();
    else if (ParenExpr *PExpr = dyn_cast<ParenExpr>(FnExpr)) {
      // Parentheses around a function disable ADL
      // (C++0x [basic.lookup.argdep]p1).
      ADL = false;
      FnExpr = PExpr->getSubExpr();
    } else if (isa<UnaryOperator>(FnExpr) &&
               cast<UnaryOperator>(FnExpr)->getOpcode()
                 == UnaryOperator::AddrOf) {
      FnExpr = cast<UnaryOperator>(FnExpr)->getSubExpr();
    } else if (DeclRefExpr *DRExpr = dyn_cast<DeclRefExpr>(FnExpr)) {
      // Qualified names disable ADL (C++0x [basic.lookup.argdep]p1).
      ADL &= !isa<QualifiedDeclRefExpr>(DRExpr);
      NDecl = dyn_cast<NamedDecl>(DRExpr->getDecl());
      break;
    } else if (UnresolvedFunctionNameExpr *DepName
                 = dyn_cast<UnresolvedFunctionNameExpr>(FnExpr)) {
      UnqualifiedName = DepName->getName();
      break;
    } else if (TemplateIdRefExpr *TemplateIdRef 
                 = dyn_cast<TemplateIdRefExpr>(FnExpr)) {
      NDecl = TemplateIdRef->getTemplateName().getAsTemplateDecl();
      if (!NDecl)
        NDecl = TemplateIdRef->getTemplateName().getAsOverloadedFunctionDecl();
      HasExplicitTemplateArgs = true;
      ExplicitTemplateArgs = TemplateIdRef->getTemplateArgs();
      NumExplicitTemplateArgs = TemplateIdRef->getNumTemplateArgs();
      
      // C++ [temp.arg.explicit]p6:
      //   [Note: For simple function names, argument dependent lookup (3.4.2)
      //   applies even when the function name is not visible within the 
      //   scope of the call. This is because the call still has the syntactic
      //   form of a function call (3.4.1). But when a function template with
      //   explicit template arguments is used, the call does not have the
      //   correct syntactic form unless there is a function template with 
      //   that name visible at the point of the call. If no such name is 
      //   visible, the call is not syntactically well-formed and 
      //   argument-dependent lookup does not apply. If some such name is 
      //   visible, argument dependent lookup applies and additional function
      //   templates may be found in other namespaces.
      //
      // The summary of this paragraph is that, if we get to this point and the
      // template-id was not a qualified name, then argument-dependent lookup
      // is still possible.
      if (TemplateIdRef->getQualifier())
        ADL = false;
      break;
    } else {
      // Any kind of name that does not refer to a declaration (or
      // set of declarations) disables ADL (C++0x [basic.lookup.argdep]p3).
      ADL = false;
      break;
    }
  }

  OverloadedFunctionDecl *Ovl = 0;
  FunctionTemplateDecl *FunctionTemplate = 0;
  if (NDecl) {