CGExpr.cpp revision fe71008c2764768f25478b16c1802755189ed7c9 
1//===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This contains code to emit Expr nodes as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CodeGenModule.h"
16#include "CGCall.h"
17#include "CGCXXABI.h"
18#include "CGRecordLayout.h"
19#include "CGObjCRuntime.h"
20#include "clang/AST/ASTContext.h"
21#include "clang/AST/DeclObjC.h"
22#include "llvm/Intrinsics.h"
23#include "clang/Frontend/CodeGenOptions.h"
24#include "llvm/Target/TargetData.h"
25using namespace clang;
26using namespace CodeGen;
27
28//===--------------------------------------------------------------------===//
29//                        Miscellaneous Helper Methods
30//===--------------------------------------------------------------------===//
31
32/// CreateTempAlloca - This creates a alloca and inserts it into the entry
33/// block.
34llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
35                                                    const llvm::Twine &Name) {
36  if (!Builder.isNamePreserving())
37    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
38  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
39}
40
41void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
42                                     llvm::Value *Init) {
43  llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
44  llvm::BasicBlock *Block = AllocaInsertPt->getParent();
45  Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
46}
47
48llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
49                                                const llvm::Twine &Name) {
50  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
51  // FIXME: Should we prefer the preferred type alignment here?
52  CharUnits Align = getContext().getTypeAlignInChars(Ty);
53  Alloc->setAlignment(Align.getQuantity());
54  return Alloc;
55}
56
57llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
58                                                 const llvm::Twine &Name) {
59  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
60  // FIXME: Should we prefer the preferred type alignment here?
61  CharUnits Align = getContext().getTypeAlignInChars(Ty);
62  Alloc->setAlignment(Align.getQuantity());
63  return Alloc;
64}
65
66/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
67/// expression and compare the result against zero, returning an Int1Ty value.
68llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
69  if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
70    llvm::Value *MemPtr = EmitScalarExpr(E);
71    return CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, MemPtr, MPT);
72  }
73
74  QualType BoolTy = getContext().BoolTy;
75  if (!E->getType()->isAnyComplexType())
76    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
77
78  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
79}
80
81/// EmitIgnoredExpr - Emit code to compute the specified expression,
82/// ignoring the result.
83void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
84  if (E->isRValue())
85    return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
86
87  // Just emit it as an l-value and drop the result.
88  EmitLValue(E);
89}
90
91/// EmitAnyExpr - Emit code to compute the specified expression which
92/// can have any type.  The result is returned as an RValue struct.
93/// If this is an aggregate expression, AggSlot indicates where the
94/// result should be returned.
95RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot AggSlot,
96                                    bool IgnoreResult) {
97  if (!hasAggregateLLVMType(E->getType()))
98    return RValue::get(EmitScalarExpr(E, IgnoreResult));
99  else if (E->getType()->isAnyComplexType())
100    return RValue::getComplex(EmitComplexExpr(E, IgnoreResult, IgnoreResult));
101
102  EmitAggExpr(E, AggSlot, IgnoreResult);
103  return AggSlot.asRValue();
104}
105
106/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
107/// always be accessible even if no aggregate location is provided.
108RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
109  AggValueSlot AggSlot = AggValueSlot::ignored();
110
111  if (hasAggregateLLVMType(E->getType()) &&
112      !E->getType()->isAnyComplexType())
113    AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
114  return EmitAnyExpr(E, AggSlot);
115}
116
117/// EmitAnyExprToMem - Evaluate an expression into a given memory
118/// location.
119void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
120                                       llvm::Value *Location,
121                                       bool IsLocationVolatile,
122                                       bool IsInit) {
123  if (E->getType()->isComplexType())
124    EmitComplexExprIntoAddr(E, Location, IsLocationVolatile);
125  else if (hasAggregateLLVMType(E->getType()))
126    EmitAggExpr(E, AggValueSlot::forAddr(Location, IsLocationVolatile, IsInit));
127  else {
128    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
129    LValue LV = MakeAddrLValue(Location, E->getType());
130    EmitStoreThroughLValue(RV, LV, E->getType());
131  }
132}
133
134namespace {
135/// \brief An adjustment to be made to the temporary created when emitting a
136/// reference binding, which accesses a particular subobject of that temporary.
137  struct SubobjectAdjustment {
138    enum { DerivedToBaseAdjustment, FieldAdjustment } Kind;
139
140    union {
141      struct {
142        const CastExpr *BasePath;
143        const CXXRecordDecl *DerivedClass;
144      } DerivedToBase;
145
146      FieldDecl *Field;
147    };
148
149    SubobjectAdjustment(const CastExpr *BasePath,
150                        const CXXRecordDecl *DerivedClass)
151      : Kind(DerivedToBaseAdjustment) {
152      DerivedToBase.BasePath = BasePath;
153      DerivedToBase.DerivedClass = DerivedClass;
154    }
155
156    SubobjectAdjustment(FieldDecl *Field)
157      : Kind(FieldAdjustment) {
158      this->Field = Field;
159    }
160  };
161}
162
163static llvm::Value *
164CreateReferenceTemporary(CodeGenFunction& CGF, QualType Type,
165                         const NamedDecl *InitializedDecl) {
166  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
167    if (VD->hasGlobalStorage()) {
168      llvm::SmallString<256> Name;
169      CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Name);
170
171      const llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
172
173      // Create the reference temporary.
174      llvm::GlobalValue *RefTemp =
175        new llvm::GlobalVariable(CGF.CGM.getModule(),
176                                 RefTempTy, /*isConstant=*/false,
177                                 llvm::GlobalValue::InternalLinkage,
178                                 llvm::Constant::getNullValue(RefTempTy),
179                                 Name.str());
180      return RefTemp;
181    }
182  }
183
184  return CGF.CreateMemTemp(Type, "ref.tmp");
185}
186
187static llvm::Value *
188EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
189                            llvm::Value *&ReferenceTemporary,
190                            const CXXDestructorDecl *&ReferenceTemporaryDtor,
191                            const NamedDecl *InitializedDecl) {
192  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
193    E = DAE->getExpr();
194
195  if (const ExprWithCleanups *TE = dyn_cast<ExprWithCleanups>(E)) {
196    CodeGenFunction::RunCleanupsScope Scope(CGF);
197
198    return EmitExprForReferenceBinding(CGF, TE->getSubExpr(),
199                                       ReferenceTemporary,
200                                       ReferenceTemporaryDtor,
201                                       InitializedDecl);
202  }
203
204  RValue RV;
205  if (E->isLValue()) {
206    // Emit the expression as an lvalue.
207    LValue LV = CGF.EmitLValue(E);
208    if (LV.isSimple())
209      return LV.getAddress();
210
211    // We have to load the lvalue.
212    RV = CGF.EmitLoadOfLValue(LV, E->getType());
213  } else {
214    QualType ResultTy = E->getType();
215
216    llvm::SmallVector<SubobjectAdjustment, 2> Adjustments;
217    while (true) {
218      if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
219        E = PE->getSubExpr();
220        continue;
221      }
222
223      if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
224        if ((CE->getCastKind() == CK_DerivedToBase ||
225             CE->getCastKind() == CK_UncheckedDerivedToBase) &&
226            E->getType()->isRecordType()) {
227          E = CE->getSubExpr();
228          CXXRecordDecl *Derived
229            = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
230          Adjustments.push_back(SubobjectAdjustment(CE, Derived));
231          continue;
232        }
233
234        if (CE->getCastKind() == CK_NoOp) {
235          E = CE->getSubExpr();
236          continue;
237        }
238      } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
239        if (!ME->isArrow() && ME->getBase()->isRValue()) {
240          assert(ME->getBase()->getType()->isRecordType());
241          if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
242            E = ME->getBase();
243            Adjustments.push_back(SubobjectAdjustment(Field));
244            continue;
245          }
246        }
247      }
248
249      // Nothing changed.
250      break;
251    }
252
253    // Create a reference temporary if necessary.
254    AggValueSlot AggSlot = AggValueSlot::ignored();
255    if (CGF.hasAggregateLLVMType(E->getType()) &&
256        !E->getType()->isAnyComplexType()) {
257      ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
258                                                    InitializedDecl);
259      AggSlot = AggValueSlot::forAddr(ReferenceTemporary, false,
260                                      InitializedDecl != 0);
261    }
262
263    RV = CGF.EmitAnyExpr(E, AggSlot);
264
265    if (InitializedDecl) {
266      // Get the destructor for the reference temporary.
267      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
268        CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
269        if (!ClassDecl->hasTrivialDestructor())
270          ReferenceTemporaryDtor = ClassDecl->getDestructor();
271      }
272    }
273
274    // Check if need to perform derived-to-base casts and/or field accesses, to
275    // get from the temporary object we created (and, potentially, for which we
276    // extended the lifetime) to the subobject we're binding the reference to.
277    if (!Adjustments.empty()) {
278      llvm::Value *Object = RV.getAggregateAddr();
279      for (unsigned I = Adjustments.size(); I != 0; --I) {
280        SubobjectAdjustment &Adjustment = Adjustments[I-1];
281        switch (Adjustment.Kind) {
282        case SubobjectAdjustment::DerivedToBaseAdjustment:
283          Object =
284              CGF.GetAddressOfBaseClass(Object,
285                                        Adjustment.DerivedToBase.DerivedClass,
286                              Adjustment.DerivedToBase.BasePath->path_begin(),
287                              Adjustment.DerivedToBase.BasePath->path_end(),
288                                        /*NullCheckValue=*/false);
289          break;
290
291        case SubobjectAdjustment::FieldAdjustment: {
292          LValue LV =
293            CGF.EmitLValueForField(Object, Adjustment.Field, 0);
294          if (LV.isSimple()) {
295            Object = LV.getAddress();
296            break;
297          }
298
299          // For non-simple lvalues, we actually have to create a copy of
300          // the object we're binding to.
301          QualType T = Adjustment.Field->getType().getNonReferenceType()
302                                                  .getUnqualifiedType();
303          Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
304          LValue TempLV = CGF.MakeAddrLValue(Object,
305                                             Adjustment.Field->getType());
306          CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV, T), TempLV, T);
307          break;
308        }
309
310        }
311      }
312
313      const llvm::Type *ResultPtrTy = CGF.ConvertType(ResultTy)->getPointerTo();
314      return CGF.Builder.CreateBitCast(Object, ResultPtrTy, "temp");
315    }
316  }
317
318  if (RV.isAggregate())
319    return RV.getAggregateAddr();
320
321  // Create a temporary variable that we can bind the reference to.
322  ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
323                                                InitializedDecl);
324
325
326  unsigned Alignment =
327    CGF.getContext().getTypeAlignInChars(E->getType()).getQuantity();
328  if (RV.isScalar())
329    CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
330                          /*Volatile=*/false, Alignment, E->getType());
331  else
332    CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
333                           /*Volatile=*/false);
334  return ReferenceTemporary;
335}
336
337RValue
338CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
339                                            const NamedDecl *InitializedDecl) {
340  llvm::Value *ReferenceTemporary = 0;
341  const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
342  llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
343                                                   ReferenceTemporaryDtor,
344                                                   InitializedDecl);
345  if (!ReferenceTemporaryDtor)
346    return RValue::get(Value);
347
348  // Make sure to call the destructor for the reference temporary.
349  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
350    if (VD->hasGlobalStorage()) {
351      llvm::Constant *DtorFn =
352        CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
353      CGF.EmitCXXGlobalDtorRegistration(DtorFn,
354                                      cast<llvm::Constant>(ReferenceTemporary));
355
356      return RValue::get(Value);
357    }
358  }
359
360  PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
361
362  return RValue::get(Value);
363}
364
365
366/// getAccessedFieldNo - Given an encoded value and a result number, return the
367/// input field number being accessed.
368unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
369                                             const llvm::Constant *Elts) {
370  if (isa<llvm::ConstantAggregateZero>(Elts))
371    return 0;
372
373  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
374}
375
376void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
377  if (!CatchUndefined)
378    return;
379
380  Address = Builder.CreateBitCast(Address, PtrToInt8Ty);
381
382  const llvm::Type *IntPtrT = IntPtrTy;
383  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, &IntPtrT, 1);
384  const llvm::IntegerType *Int1Ty = llvm::Type::getInt1Ty(VMContext);
385
386  // In time, people may want to control this and use a 1 here.
387  llvm::Value *Arg = llvm::ConstantInt::get(Int1Ty, 0);
388  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
389  llvm::BasicBlock *Cont = createBasicBlock();
390  llvm::BasicBlock *Check = createBasicBlock();
391  llvm::Value *NegativeOne = llvm::ConstantInt::get(IntPtrTy, -1ULL);
392  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
393
394  EmitBlock(Check);
395  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
396                                        llvm::ConstantInt::get(IntPtrTy, Size)),
397                       Cont, getTrapBB());
398  EmitBlock(Cont);
399}
400
401
402CodeGenFunction::ComplexPairTy CodeGenFunction::
403EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
404                         bool isInc, bool isPre) {
405  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
406                                            LV.isVolatileQualified());
407
408  llvm::Value *NextVal;
409  if (isa<llvm::IntegerType>(InVal.first->getType())) {
410    uint64_t AmountVal = isInc ? 1 : -1;
411    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
412
413    // Add the inc/dec to the real part.
414    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
415  } else {
416    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
417    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
418    if (!isInc)
419      FVal.changeSign();
420    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
421
422    // Add the inc/dec to the real part.
423    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
424  }
425
426  ComplexPairTy IncVal(NextVal, InVal.second);
427
428  // Store the updated result through the lvalue.
429  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
430
431  // If this is a postinc, return the value read from memory, otherwise use the
432  // updated value.
433  return isPre ? IncVal : InVal;
434}
435
436
437//===----------------------------------------------------------------------===//
438//                         LValue Expression Emission
439//===----------------------------------------------------------------------===//
440
441RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
442  if (Ty->isVoidType())
443    return RValue::get(0);
444
445  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
446    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
447    llvm::Value *U = llvm::UndefValue::get(EltTy);
448    return RValue::getComplex(std::make_pair(U, U));
449  }
450
451  // If this is a use of an undefined aggregate type, the aggregate must have an
452  // identifiable address.  Just because the contents of the value are undefined
453  // doesn't mean that the address can't be taken and compared.
454  if (hasAggregateLLVMType(Ty)) {
455    llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
456    return RValue::getAggregate(DestPtr);
457  }
458
459  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
460}
461
462RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
463                                              const char *Name) {
464  ErrorUnsupported(E, Name);
465  return GetUndefRValue(E->getType());
466}
467
468LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
469                                              const char *Name) {
470  ErrorUnsupported(E, Name);
471  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
472  return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
473}
474
475LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
476  LValue LV = EmitLValue(E);
477  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
478    EmitCheck(LV.getAddress(),
479              getContext().getTypeSizeInChars(E->getType()).getQuantity());
480  return LV;
481}
482
483/// EmitLValue - Emit code to compute a designator that specifies the location
484/// of the expression.
485///
486/// This can return one of two things: a simple address or a bitfield reference.
487/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
488/// an LLVM pointer type.
489///
490/// If this returns a bitfield reference, nothing about the pointee type of the
491/// LLVM value is known: For example, it may not be a pointer to an integer.
492///
493/// If this returns a normal address, and if the lvalue's C type is fixed size,
494/// this method guarantees that the returned pointer type will point to an LLVM
495/// type of the same size of the lvalue's type.  If the lvalue has a variable
496/// length type, this is not possible.
497///
498LValue CodeGenFunction::EmitLValue(const Expr *E) {
499  llvm::DenseMap<const Expr *, LValue>::iterator I =
500                                      CGF.ConditionalSaveLValueExprs.find(E);
501  if (I != CGF.ConditionalSaveLValueExprs.end())
502    return I->second;
503
504  switch (E->getStmtClass()) {
505  default: return EmitUnsupportedLValue(E, "l-value expression");
506
507  case Expr::ObjCSelectorExprClass:
508  return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
509  case Expr::ObjCIsaExprClass:
510    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
511  case Expr::BinaryOperatorClass:
512    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
513  case Expr::CompoundAssignOperatorClass:
514    if (!E->getType()->isAnyComplexType())
515      return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
516    return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
517  case Expr::CallExprClass:
518  case Expr::CXXMemberCallExprClass:
519  case Expr::CXXOperatorCallExprClass:
520    return EmitCallExprLValue(cast<CallExpr>(E));
521  case Expr::VAArgExprClass:
522    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
523  case Expr::DeclRefExprClass:
524    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
525  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
526  case Expr::PredefinedExprClass:
527    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
528  case Expr::StringLiteralClass:
529    return EmitStringLiteralLValue(cast<StringLiteral>(E));
530  case Expr::ObjCEncodeExprClass:
531    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
532
533  case Expr::BlockDeclRefExprClass:
534    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
535
536  case Expr::CXXTemporaryObjectExprClass:
537  case Expr::CXXConstructExprClass:
538    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
539  case Expr::CXXBindTemporaryExprClass:
540    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
541  case Expr::ExprWithCleanupsClass:
542    return EmitExprWithCleanupsLValue(cast<ExprWithCleanups>(E));
543  case Expr::CXXScalarValueInitExprClass:
544    return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
545  case Expr::CXXDefaultArgExprClass:
546    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
547  case Expr::CXXTypeidExprClass:
548    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
549
550  case Expr::ObjCMessageExprClass:
551    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
552  case Expr::ObjCIvarRefExprClass:
553    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
554  case Expr::ObjCPropertyRefExprClass:
555    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
556  case Expr::StmtExprClass:
557    return EmitStmtExprLValue(cast<StmtExpr>(E));
558  case Expr::UnaryOperatorClass:
559    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
560  case Expr::ArraySubscriptExprClass:
561    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
562  case Expr::ExtVectorElementExprClass:
563    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
564  case Expr::MemberExprClass:
565    return EmitMemberExpr(cast<MemberExpr>(E));
566  case Expr::CompoundLiteralExprClass:
567    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
568  case Expr::ConditionalOperatorClass:
569    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
570  case Expr::ChooseExprClass:
571    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
572  case Expr::ImplicitCastExprClass:
573  case Expr::CStyleCastExprClass:
574  case Expr::CXXFunctionalCastExprClass:
575  case Expr::CXXStaticCastExprClass:
576  case Expr::CXXDynamicCastExprClass:
577  case Expr::CXXReinterpretCastExprClass:
578  case Expr::CXXConstCastExprClass:
579    return EmitCastLValue(cast<CastExpr>(E));
580  }
581}
582
583llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
584                                              unsigned Alignment, QualType Ty,
585                                              llvm::MDNode *TBAAInfo) {
586  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
587  if (Volatile)
588    Load->setVolatile(true);
589  if (Alignment)
590    Load->setAlignment(Alignment);
591  if (TBAAInfo)
592    CGM.DecorateInstruction(Load, TBAAInfo);
593
594  return EmitFromMemory(Load, Ty);
595}
596
597static bool isBooleanUnderlyingType(QualType Ty) {
598  if (const EnumType *ET = dyn_cast<EnumType>(Ty))
599    return ET->getDecl()->getIntegerType()->isBooleanType();
600  return false;
601}
602
603llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
604  // Bool has a different representation in memory than in registers.
605  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
606    // This should really always be an i1, but sometimes it's already
607    // an i8, and it's awkward to track those cases down.
608    if (Value->getType()->isIntegerTy(1))
609      return Builder.CreateZExt(Value, Builder.getInt8Ty(), "frombool");
610    assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
611  }
612
613  return Value;
614}
615
616llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
617  // Bool has a different representation in memory than in registers.
618  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
619    assert(Value->getType()->isIntegerTy(8) && "memory rep of bool not i8");
620    return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
621  }
622
623  return Value;
624}
625
626void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
627                                        bool Volatile, unsigned Alignment,
628                                        QualType Ty,
629                                        llvm::MDNode *TBAAInfo) {
630  Value = EmitToMemory(Value, Ty);
631  llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
632  if (Alignment)
633    Store->setAlignment(Alignment);
634  if (TBAAInfo)
635    CGM.DecorateInstruction(Store, TBAAInfo);
636}
637
638/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
639/// method emits the address of the lvalue, then loads the result as an rvalue,
640/// returning the rvalue.
641RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
642  if (LV.isObjCWeak()) {
643    // load of a __weak object.
644    llvm::Value *AddrWeakObj = LV.getAddress();
645    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
646                                                             AddrWeakObj));
647  }
648
649  if (LV.isSimple()) {
650    llvm::Value *Ptr = LV.getAddress();
651
652    // Functions are l-values that don't require loading.
653    if (ExprType->isFunctionType())
654      return RValue::get(Ptr);
655
656    // Everything needs a load.
657    return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
658                                        LV.getAlignment(), ExprType,
659                                        LV.getTBAAInfo()));
660
661  }
662
663  if (LV.isVectorElt()) {
664    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
665                                          LV.isVolatileQualified(), "tmp");
666    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
667                                                    "vecext"));
668  }
669
670  // If this is a reference to a subset of the elements of a vector, either
671  // shuffle the input or extract/insert them as appropriate.
672  if (LV.isExtVectorElt())
673    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
674
675  if (LV.isBitField())
676    return EmitLoadOfBitfieldLValue(LV, ExprType);
677
678  assert(LV.isPropertyRef() && "Unknown LValue type!");
679  return EmitLoadOfPropertyRefLValue(LV);
680}
681
682RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
683                                                 QualType ExprType) {
684  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
685
686  // Get the output type.
687  const llvm::Type *ResLTy = ConvertType(ExprType);
688  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
689
690  // Compute the result as an OR of all of the individual component accesses.
691  llvm::Value *Res = 0;
692  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
693    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
694
695    // Get the field pointer.
696    llvm::Value *Ptr = LV.getBitFieldBaseAddr();
697
698    // Only offset by the field index if used, so that incoming values are not
699    // required to be structures.
700    if (AI.FieldIndex)
701      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
702
703    // Offset by the byte offset, if used.
704    if (AI.FieldByteOffset) {
705      const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
706      Ptr = Builder.CreateBitCast(Ptr, i8PTy);
707      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
708    }
709
710    // Cast to the access type.
711    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(VMContext, AI.AccessWidth,
712                                                    ExprType.getAddressSpace());
713    Ptr = Builder.CreateBitCast(Ptr, PTy);
714
715    // Perform the load.
716    llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
717    if (AI.AccessAlignment)
718      Load->setAlignment(AI.AccessAlignment);
719
720    // Shift out unused low bits and mask out unused high bits.
721    llvm::Value *Val = Load;
722    if (AI.FieldBitStart)
723      Val = Builder.CreateLShr(Load, AI.FieldBitStart);
724    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
725                                                            AI.TargetBitWidth),
726                            "bf.clear");
727
728    // Extend or truncate to the target size.
729    if (AI.AccessWidth < ResSizeInBits)
730      Val = Builder.CreateZExt(Val, ResLTy);
731    else if (AI.AccessWidth > ResSizeInBits)
732      Val = Builder.CreateTrunc(Val, ResLTy);
733
734    // Shift into place, and OR into the result.
735    if (AI.TargetBitOffset)
736      Val = Builder.CreateShl(Val, AI.TargetBitOffset);
737    Res = Res ? Builder.CreateOr(Res, Val) : Val;
738  }
739
740  // If the bit-field is signed, perform the sign-extension.
741  //
742  // FIXME: This can easily be folded into the load of the high bits, which
743  // could also eliminate the mask of high bits in some situations.
744  if (Info.isSigned()) {
745    unsigned ExtraBits = ResSizeInBits - Info.getSize();
746    if (ExtraBits)
747      Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
748                               ExtraBits, "bf.val.sext");
749  }
750
751  return RValue::get(Res);
752}
753
754// If this is a reference to a subset of the elements of a vector, create an
755// appropriate shufflevector.
756RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
757                                                         QualType ExprType) {
758  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
759                                        LV.isVolatileQualified(), "tmp");
760
761  const llvm::Constant *Elts = LV.getExtVectorElts();
762
763  // If the result of the expression is a non-vector type, we must be extracting
764  // a single element.  Just codegen as an extractelement.
765  const VectorType *ExprVT = ExprType->getAs<VectorType>();
766  if (!ExprVT) {
767    unsigned InIdx = getAccessedFieldNo(0, Elts);
768    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
769    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
770  }
771
772  // Always use shuffle vector to try to retain the original program structure
773  unsigned NumResultElts = ExprVT->getNumElements();
774
775  llvm::SmallVector<llvm::Constant*, 4> Mask;
776  for (unsigned i = 0; i != NumResultElts; ++i) {
777    unsigned InIdx = getAccessedFieldNo(i, Elts);
778    Mask.push_back(llvm::ConstantInt::get(Int32Ty, InIdx));
779  }
780
781  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
782  Vec = Builder.CreateShuffleVector(Vec,
783                                    llvm::UndefValue::get(Vec->getType()),
784                                    MaskV, "tmp");
785  return RValue::get(Vec);
786}
787
788
789
790/// EmitStoreThroughLValue - Store the specified rvalue into the specified
791/// lvalue, where both are guaranteed to the have the same type, and that type
792/// is 'Ty'.
793void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
794                                             QualType Ty) {
795  if (!Dst.isSimple()) {
796    if (Dst.isVectorElt()) {
797      // Read/modify/write the vector, inserting the new element.
798      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
799                                            Dst.isVolatileQualified(), "tmp");
800      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
801                                        Dst.getVectorIdx(), "vecins");
802      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
803      return;
804    }
805
806    // If this is an update of extended vector elements, insert them as
807    // appropriate.
808    if (Dst.isExtVectorElt())
809      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
810
811    if (Dst.isBitField())
812      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
813
814    assert(Dst.isPropertyRef() && "Unknown LValue type");
815    return EmitStoreThroughPropertyRefLValue(Src, Dst);
816  }
817
818  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
819    // load of a __weak object.
820    llvm::Value *LvalueDst = Dst.getAddress();
821    llvm::Value *src = Src.getScalarVal();
822     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
823    return;
824  }
825
826  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
827    // load of a __strong object.
828    llvm::Value *LvalueDst = Dst.getAddress();
829    llvm::Value *src = Src.getScalarVal();
830    if (Dst.isObjCIvar()) {
831      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
832      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
833      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
834      llvm::Value *dst = RHS;
835      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
836      llvm::Value *LHS =
837        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
838      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
839      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
840                                              BytesBetween);
841    } else if (Dst.isGlobalObjCRef()) {
842      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
843                                                Dst.isThreadLocalRef());
844    }
845    else
846      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
847    return;
848  }
849
850  assert(Src.isScalar() && "Can't emit an agg store with this method");
851  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
852                    Dst.isVolatileQualified(), Dst.getAlignment(), Ty,
853                    Dst.getTBAAInfo());
854}
855
856void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
857                                                     QualType Ty,
858                                                     llvm::Value **Result) {
859  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
860
861  // Get the output type.
862  const llvm::Type *ResLTy = ConvertTypeForMem(Ty);
863  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
864
865  // Get the source value, truncated to the width of the bit-field.
866  llvm::Value *SrcVal = Src.getScalarVal();
867
868  if (Ty->isBooleanType())
869    SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
870
871  SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
872                                                                Info.getSize()),
873                             "bf.value");
874
875  // Return the new value of the bit-field, if requested.
876  if (Result) {
877    // Cast back to the proper type for result.
878    const llvm::Type *SrcTy = Src.getScalarVal()->getType();
879    llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
880                                                   "bf.reload.val");
881
882    // Sign extend if necessary.
883    if (Info.isSigned()) {
884      unsigned ExtraBits = ResSizeInBits - Info.getSize();
885      if (ExtraBits)
886        ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
887                                       ExtraBits, "bf.reload.sext");
888    }
889
890    *Result = ReloadVal;
891  }
892
893  // Iterate over the components, writing each piece to memory.
894  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
895    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
896
897    // Get the field pointer.
898    llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
899
900    // Only offset by the field index if used, so that incoming values are not
901    // required to be structures.
902    if (AI.FieldIndex)
903      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
904
905    // Offset by the byte offset, if used.
906    if (AI.FieldByteOffset) {
907      const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
908      Ptr = Builder.CreateBitCast(Ptr, i8PTy);
909      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
910    }
911
912    // Cast to the access type.
913    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(VMContext, AI.AccessWidth,
914                                                     Ty.getAddressSpace());
915    Ptr = Builder.CreateBitCast(Ptr, PTy);
916
917    // Extract the piece of the bit-field value to write in this access, limited
918    // to the values that are part of this access.
919    llvm::Value *Val = SrcVal;
920    if (AI.TargetBitOffset)
921      Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
922    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
923                                                            AI.TargetBitWidth));
924
925    // Extend or truncate to the access size.
926    const llvm::Type *AccessLTy =
927      llvm::Type::getIntNTy(VMContext, AI.AccessWidth);
928    if (ResSizeInBits < AI.AccessWidth)
929      Val = Builder.CreateZExt(Val, AccessLTy);
930    else if (ResSizeInBits > AI.AccessWidth)
931      Val = Builder.CreateTrunc(Val, AccessLTy);
932
933    // Shift into the position in memory.
934    if (AI.FieldBitStart)
935      Val = Builder.CreateShl(Val, AI.FieldBitStart);
936
937    // If necessary, load and OR in bits that are outside of the bit-field.
938    if (AI.TargetBitWidth != AI.AccessWidth) {
939      llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
940      if (AI.AccessAlignment)
941        Load->setAlignment(AI.AccessAlignment);
942
943      // Compute the mask for zeroing the bits that are part of the bit-field.
944      llvm::APInt InvMask =
945        ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
946                                 AI.FieldBitStart + AI.TargetBitWidth);
947
948      // Apply the mask and OR in to the value to write.
949      Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
950    }
951
952    // Write the value.
953    llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
954                                                 Dst.isVolatileQualified());
955    if (AI.AccessAlignment)
956      Store->setAlignment(AI.AccessAlignment);
957  }
958}
959
960void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
961                                                               LValue Dst,
962                                                               QualType Ty) {
963  // This access turns into a read/modify/write of the vector.  Load the input
964  // value now.
965  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
966                                        Dst.isVolatileQualified(), "tmp");
967  const llvm::Constant *Elts = Dst.getExtVectorElts();
968
969  llvm::Value *SrcVal = Src.getScalarVal();
970
971  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
972    unsigned NumSrcElts = VTy->getNumElements();
973    unsigned NumDstElts =
974       cast<llvm::VectorType>(Vec->getType())->getNumElements();
975    if (NumDstElts == NumSrcElts) {
976      // Use shuffle vector is the src and destination are the same number of
977      // elements and restore the vector mask since it is on the side it will be
978      // stored.
979      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
980      for (unsigned i = 0; i != NumSrcElts; ++i) {
981        unsigned InIdx = getAccessedFieldNo(i, Elts);
982        Mask[InIdx] = llvm::ConstantInt::get(Int32Ty, i);
983      }
984
985      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
986      Vec = Builder.CreateShuffleVector(SrcVal,
987                                        llvm::UndefValue::get(Vec->getType()),
988                                        MaskV, "tmp");
989    } else if (NumDstElts > NumSrcElts) {
990      // Extended the source vector to the same length and then shuffle it
991      // into the destination.
992      // FIXME: since we're shuffling with undef, can we just use the indices
993      //        into that?  This could be simpler.
994      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
995      unsigned i;
996      for (i = 0; i != NumSrcElts; ++i)
997        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
998      for (; i != NumDstElts; ++i)
999        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
1000      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
1001                                                        ExtMask.size());
1002      llvm::Value *ExtSrcVal =
1003        Builder.CreateShuffleVector(SrcVal,
1004                                    llvm::UndefValue::get(SrcVal->getType()),
1005                                    ExtMaskV, "tmp");
1006      // build identity
1007      llvm::SmallVector<llvm::Constant*, 4> Mask;
1008      for (unsigned i = 0; i != NumDstElts; ++i)
1009        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1010
1011      // modify when what gets shuffled in
1012      for (unsigned i = 0; i != NumSrcElts; ++i) {
1013        unsigned Idx = getAccessedFieldNo(i, Elts);
1014        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
1015      }
1016      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
1017      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
1018    } else {
1019      // We should never shorten the vector
1020      assert(0 && "unexpected shorten vector length");
1021    }
1022  } else {
1023    // If the Src is a scalar (not a vector) it must be updating one element.
1024    unsigned InIdx = getAccessedFieldNo(0, Elts);
1025    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1026    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
1027  }
1028
1029  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1030}
1031
1032// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1033// generating write-barries API. It is currently a global, ivar,
1034// or neither.
1035static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1036                                 LValue &LV) {
1037  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
1038    return;
1039
1040  if (isa<ObjCIvarRefExpr>(E)) {
1041    LV.setObjCIvar(true);
1042    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1043    LV.setBaseIvarExp(Exp->getBase());
1044    LV.setObjCArray(E->getType()->isArrayType());
1045    return;
1046  }
1047
1048  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1049    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1050      if (VD->hasGlobalStorage()) {
1051        LV.setGlobalObjCRef(true);
1052        LV.setThreadLocalRef(VD->isThreadSpecified());
1053      }
1054    }
1055    LV.setObjCArray(E->getType()->isArrayType());
1056    return;
1057  }
1058
1059  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1060    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1061    return;
1062  }
1063
1064  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1065    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1066    if (LV.isObjCIvar()) {
1067      // If cast is to a structure pointer, follow gcc's behavior and make it
1068      // a non-ivar write-barrier.
1069      QualType ExpTy = E->getType();
1070      if (ExpTy->isPointerType())
1071        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1072      if (ExpTy->isRecordType())
1073        LV.setObjCIvar(false);
1074    }
1075    return;
1076  }
1077  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1078    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1079    return;
1080  }
1081
1082  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1083    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1084    return;
1085  }
1086
1087  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1088    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1089    if (LV.isObjCIvar() && !LV.isObjCArray())
1090      // Using array syntax to assigning to what an ivar points to is not
1091      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1092      LV.setObjCIvar(false);
1093    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1094      // Using array syntax to assigning to what global points to is not
1095      // same as assigning to the global itself. {id *G;} G[i] = 0;
1096      LV.setGlobalObjCRef(false);
1097    return;
1098  }
1099
1100  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1101    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1102    // We don't know if member is an 'ivar', but this flag is looked at
1103    // only in the context of LV.isObjCIvar().
1104    LV.setObjCArray(E->getType()->isArrayType());
1105    return;
1106  }
1107}
1108
1109static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1110                                      const Expr *E, const VarDecl *VD) {
1111  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1112         "Var decl must have external storage or be a file var decl!");
1113
1114  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1115  if (VD->getType()->isReferenceType())
1116    V = CGF.Builder.CreateLoad(V, "tmp");
1117  unsigned Alignment = CGF.getContext().getDeclAlign(VD).getQuantity();
1118  LValue LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1119  setObjCGCLValueClass(CGF.getContext(), E, LV);
1120  return LV;
1121}
1122
1123static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1124                                      const Expr *E, const FunctionDecl *FD) {
1125  llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1126  if (!FD->hasPrototype()) {
1127    if (const FunctionProtoType *Proto =
1128            FD->getType()->getAs<FunctionProtoType>()) {
1129      // Ugly case: for a K&R-style definition, the type of the definition
1130      // isn't the same as the type of a use.  Correct for this with a
1131      // bitcast.
1132      QualType NoProtoType =
1133          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1134      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1135      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1136    }
1137  }
1138  unsigned Alignment = CGF.getContext().getDeclAlign(FD).getQuantity();
1139  return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1140}
1141
1142LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1143  const NamedDecl *ND = E->getDecl();
1144  unsigned Alignment = CGF.getContext().getDeclAlign(ND).getQuantity();
1145
1146  if (ND->hasAttr<WeakRefAttr>()) {
1147    const ValueDecl *VD = cast<ValueDecl>(ND);
1148    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1149    return MakeAddrLValue(Aliasee, E->getType(), Alignment);
1150  }
1151
1152  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1153
1154    // Check if this is a global variable.
1155    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1156      return EmitGlobalVarDeclLValue(*this, E, VD);
1157
1158    bool NonGCable = VD->hasLocalStorage() &&
1159                     !VD->getType()->isReferenceType() &&
1160                     !VD->hasAttr<BlocksAttr>();
1161
1162    llvm::Value *V = LocalDeclMap[VD];
1163    if (!V && VD->isStaticLocal())
1164      V = CGM.getStaticLocalDeclAddress(VD);
1165    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1166
1167    if (VD->hasAttr<BlocksAttr>()) {
1168      V = Builder.CreateStructGEP(V, 1, "forwarding");
1169      V = Builder.CreateLoad(V);
1170      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
1171                                  VD->getNameAsString());
1172    }
1173    if (VD->getType()->isReferenceType())
1174      V = Builder.CreateLoad(V, "tmp");
1175
1176    LValue LV = MakeAddrLValue(V, E->getType(), Alignment);
1177    if (NonGCable) {
1178      LV.getQuals().removeObjCGCAttr();
1179      LV.setNonGC(true);
1180    }
1181    setObjCGCLValueClass(getContext(), E, LV);
1182    return LV;
1183  }
1184
1185  // If we're emitting an instance method as an independent lvalue,
1186  // we're actually emitting a member pointer.
1187  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1188    if (MD->isInstance()) {
1189      llvm::Value *V = CGM.getCXXABI().EmitMemberPointer(MD);
1190      return MakeAddrLValue(V, MD->getType(), Alignment);
1191    }
1192  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1193    return EmitFunctionDeclLValue(*this, E, FD);
1194
1195  // If we're emitting a field as an independent lvalue, we're
1196  // actually emitting a member pointer.
1197  if (const FieldDecl *FD = dyn_cast<FieldDecl>(ND)) {
1198    llvm::Value *V = CGM.getCXXABI().EmitMemberPointer(FD);
1199    return MakeAddrLValue(V, FD->getType(), Alignment);
1200  }
1201
1202  assert(false && "Unhandled DeclRefExpr");
1203
1204  // an invalid LValue, but the assert will
1205  // ensure that this point is never reached.
1206  return LValue();
1207}
1208
1209LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1210  unsigned Alignment =
1211    CGF.getContext().getDeclAlign(E->getDecl()).getQuantity();
1212  return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
1213}
1214
1215LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1216  // __extension__ doesn't affect lvalue-ness.
1217  if (E->getOpcode() == UO_Extension)
1218    return EmitLValue(E->getSubExpr());
1219
1220  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1221  switch (E->getOpcode()) {
1222  default: assert(0 && "Unknown unary operator lvalue!");
1223  case UO_Deref: {
1224    QualType T = E->getSubExpr()->getType()->getPointeeType();
1225    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1226
1227    LValue LV = MakeAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1228    LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1229
1230    // We should not generate __weak write barrier on indirect reference
1231    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1232    // But, we continue to generate __strong write barrier on indirect write
1233    // into a pointer to object.
1234    if (getContext().getLangOptions().ObjC1 &&
1235        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1236        LV.isObjCWeak())
1237      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1238    return LV;
1239  }
1240  case UO_Real:
1241  case UO_Imag: {
1242    LValue LV = EmitLValue(E->getSubExpr());
1243    assert(LV.isSimple() && "real/imag on non-ordinary l-value");
1244    llvm::Value *Addr = LV.getAddress();
1245
1246    // real and imag are valid on scalars.  This is a faster way of
1247    // testing that.
1248    if (!cast<llvm::PointerType>(Addr->getType())
1249           ->getElementType()->isStructTy()) {
1250      assert(E->getSubExpr()->getType()->isArithmeticType());
1251      return LV;
1252    }
1253
1254    assert(E->getSubExpr()->getType()->isAnyComplexType());
1255
1256    unsigned Idx = E->getOpcode() == UO_Imag;
1257    return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1258                                                  Idx, "idx"),
1259                          ExprTy);
1260  }
1261  case UO_PreInc:
1262  case UO_PreDec: {
1263    LValue LV = EmitLValue(E->getSubExpr());
1264    bool isInc = E->getOpcode() == UO_PreInc;
1265
1266    if (E->getType()->isAnyComplexType())
1267      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1268    else
1269      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1270    return LV;
1271  }
1272  }
1273}
1274
1275LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1276  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1277                        E->getType());
1278}
1279
1280LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1281  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1282                        E->getType());
1283}
1284
1285
1286LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1287  switch (E->getIdentType()) {
1288  default:
1289    return EmitUnsupportedLValue(E, "predefined expression");
1290
1291  case PredefinedExpr::Func:
1292  case PredefinedExpr::Function:
1293  case PredefinedExpr::PrettyFunction: {
1294    unsigned Type = E->getIdentType();
1295    std::string GlobalVarName;
1296
1297    switch (Type) {
1298    default: assert(0 && "Invalid type");
1299    case PredefinedExpr::Func:
1300      GlobalVarName = "__func__.";
1301      break;
1302    case PredefinedExpr::Function:
1303      GlobalVarName = "__FUNCTION__.";
1304      break;
1305    case PredefinedExpr::PrettyFunction:
1306      GlobalVarName = "__PRETTY_FUNCTION__.";
1307      break;
1308    }
1309
1310    llvm::StringRef FnName = CurFn->getName();
1311    if (FnName.startswith("\01"))
1312      FnName = FnName.substr(1);
1313    GlobalVarName += FnName;
1314
1315    const Decl *CurDecl = CurCodeDecl;
1316    if (CurDecl == 0)
1317      CurDecl = getContext().getTranslationUnitDecl();
1318
1319    std::string FunctionName =
1320      PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl);
1321
1322    llvm::Constant *C =
1323      CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1324    return MakeAddrLValue(C, E->getType());
1325  }
1326  }
1327}
1328
1329llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1330  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1331
1332  // If we are not optimzing, don't collapse all calls to trap in the function
1333  // to the same call, that way, in the debugger they can see which operation
1334  // did in fact fail.  If we are optimizing, we collapse all calls to trap down
1335  // to just one per function to save on codesize.
1336  if (GCO.OptimizationLevel && TrapBB)
1337    return TrapBB;
1338
1339  llvm::BasicBlock *Cont = 0;
1340  if (HaveInsertPoint()) {
1341    Cont = createBasicBlock("cont");
1342    EmitBranch(Cont);
1343  }
1344  TrapBB = createBasicBlock("trap");
1345  EmitBlock(TrapBB);
1346
1347  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1348  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1349  TrapCall->setDoesNotReturn();
1350  TrapCall->setDoesNotThrow();
1351  Builder.CreateUnreachable();
1352
1353  if (Cont)
1354    EmitBlock(Cont);
1355  return TrapBB;
1356}
1357
1358/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
1359/// array to pointer, return the array subexpression.
1360static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
1361  // If this isn't just an array->pointer decay, bail out.
1362  const CastExpr *CE = dyn_cast<CastExpr>(E);
1363  if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
1364    return 0;
1365
1366  // If this is a decay from variable width array, bail out.
1367  const Expr *SubExpr = CE->getSubExpr();
1368  if (SubExpr->getType()->isVariableArrayType())
1369    return 0;
1370
1371  return SubExpr;
1372}
1373
1374LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1375  // The index must always be an integer, which is not an aggregate.  Emit it.
1376  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1377  QualType IdxTy  = E->getIdx()->getType();
1378  bool IdxSigned = IdxTy->isSignedIntegerType();
1379
1380  // If the base is a vector type, then we are forming a vector element lvalue
1381  // with this subscript.
1382  if (E->getBase()->getType()->isVectorType()) {
1383    // Emit the vector as an lvalue to get its address.
1384    LValue LHS = EmitLValue(E->getBase());
1385    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1386    Idx = Builder.CreateIntCast(Idx, CGF.Int32Ty, IdxSigned, "vidx");
1387    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1388                                 E->getBase()->getType().getCVRQualifiers());
1389  }
1390
1391  // Extend or truncate the index type to 32 or 64-bits.
1392  if (!Idx->getType()->isIntegerTy(LLVMPointerWidth))
1393    Idx = Builder.CreateIntCast(Idx, IntPtrTy,
1394                                IdxSigned, "idxprom");
1395
1396  // FIXME: As llvm implements the object size checking, this can come out.
1397  if (CatchUndefined) {
1398    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())){
1399      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1400        if (ICE->getCastKind() == CK_ArrayToPointerDecay) {
1401          if (const ConstantArrayType *CAT
1402              = getContext().getAsConstantArrayType(DRE->getType())) {
1403            llvm::APInt Size = CAT->getSize();
1404            llvm::BasicBlock *Cont = createBasicBlock("cont");
1405            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1406                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1407                                 Cont, getTrapBB());
1408            EmitBlock(Cont);
1409          }
1410        }
1411      }
1412    }
1413  }
1414
1415  // We know that the pointer points to a type of the correct size, unless the
1416  // size is a VLA or Objective-C interface.
1417  llvm::Value *Address = 0;
1418  if (const VariableArrayType *VAT =
1419        getContext().getAsVariableArrayType(E->getType())) {
1420    llvm::Value *VLASize = GetVLASize(VAT);
1421
1422    Idx = Builder.CreateMul(Idx, VLASize);
1423
1424    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1425
1426    // The base must be a pointer, which is not an aggregate.  Emit it.
1427    llvm::Value *Base = EmitScalarExpr(E->getBase());
1428
1429    Address = Builder.CreateInBoundsGEP(Builder.CreateBitCast(Base, i8PTy),
1430                                        Idx, "arrayidx");
1431    Address = Builder.CreateBitCast(Address, Base->getType());
1432  } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
1433    // Indexing over an interface, as in "NSString *P; P[4];"
1434    llvm::Value *InterfaceSize =
1435      llvm::ConstantInt::get(Idx->getType(),
1436          getContext().getTypeSizeInChars(OIT).getQuantity());
1437
1438    Idx = Builder.CreateMul(Idx, InterfaceSize);
1439
1440    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1441
1442    // The base must be a pointer, which is not an aggregate.  Emit it.
1443    llvm::Value *Base = EmitScalarExpr(E->getBase());
1444    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1445                                Idx, "arrayidx");
1446    Address = Builder.CreateBitCast(Address, Base->getType());
1447  } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
1448    // If this is A[i] where A is an array, the frontend will have decayed the
1449    // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
1450    // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
1451    // "gep x, i" here.  Emit one "gep A, 0, i".
1452    assert(Array->getType()->isArrayType() &&
1453           "Array to pointer decay must have array source type!");
1454    llvm::Value *ArrayPtr = EmitLValue(Array).getAddress();
1455    llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
1456    llvm::Value *Args[] = { Zero, Idx };
1457
1458    Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, Args+2, "arrayidx");
1459  } else {
1460    // The base must be a pointer, which is not an aggregate.  Emit it.
1461    llvm::Value *Base = EmitScalarExpr(E->getBase());
1462    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1463  }
1464
1465  QualType T = E->getBase()->getType()->getPointeeType();
1466  assert(!T.isNull() &&
1467         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1468
1469  LValue LV = MakeAddrLValue(Address, T);
1470  LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
1471
1472  if (getContext().getLangOptions().ObjC1 &&
1473      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1474    LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1475    setObjCGCLValueClass(getContext(), E, LV);
1476  }
1477  return LV;
1478}
1479
1480static
1481llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1482                                       llvm::SmallVector<unsigned, 4> &Elts) {
1483  llvm::SmallVector<llvm::Constant*, 4> CElts;
1484
1485  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1486  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1487    CElts.push_back(llvm::ConstantInt::get(Int32Ty, Elts[i]));
1488
1489  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1490}
1491
1492LValue CodeGenFunction::
1493EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1494  // Emit the base vector as an l-value.
1495  LValue Base;
1496
1497  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1498  if (E->isArrow()) {
1499    // If it is a pointer to a vector, emit the address and form an lvalue with
1500    // it.
1501    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1502    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1503    Base = MakeAddrLValue(Ptr, PT->getPointeeType());
1504    Base.getQuals().removeObjCGCAttr();
1505  } else if (E->getBase()->isGLValue()) {
1506    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1507    // emit the base as an lvalue.
1508    assert(E->getBase()->getType()->isVectorType());
1509    Base = EmitLValue(E->getBase());
1510  } else {
1511    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1512    assert(E->getBase()->getType()->getAs<VectorType>() &&
1513           "Result must be a vector");
1514    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1515
1516    // Store the vector to memory (because LValue wants an address).
1517    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1518    Builder.CreateStore(Vec, VecMem);
1519    Base = MakeAddrLValue(VecMem, E->getBase()->getType());
1520  }
1521
1522  // Encode the element access list into a vector of unsigned indices.
1523  llvm::SmallVector<unsigned, 4> Indices;
1524  E->getEncodedElementAccess(Indices);
1525
1526  if (Base.isSimple()) {
1527    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1528    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1529                                    Base.getVRQualifiers());
1530  }
1531  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1532
1533  llvm::Constant *BaseElts = Base.getExtVectorElts();
1534  llvm::SmallVector<llvm::Constant *, 4> CElts;
1535
1536  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1537    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1538      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1539    else
1540      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1541  }
1542  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1543  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1544                                  Base.getVRQualifiers());
1545}
1546
1547LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1548  bool isNonGC = false;
1549  Expr *BaseExpr = E->getBase();
1550  llvm::Value *BaseValue = NULL;
1551  Qualifiers BaseQuals;
1552
1553  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1554  if (E->isArrow()) {
1555    BaseValue = EmitScalarExpr(BaseExpr);
1556    const PointerType *PTy =
1557      BaseExpr->getType()->getAs<PointerType>();
1558    BaseQuals = PTy->getPointeeType().getQualifiers();
1559  } else {
1560    LValue BaseLV = EmitLValue(BaseExpr);
1561    if (BaseLV.isNonGC())
1562      isNonGC = true;
1563    // FIXME: this isn't right for bitfields.
1564    BaseValue = BaseLV.getAddress();
1565    QualType BaseTy = BaseExpr->getType();
1566    BaseQuals = BaseTy.getQualifiers();
1567  }
1568
1569  NamedDecl *ND = E->getMemberDecl();
1570  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1571    LValue LV = EmitLValueForField(BaseValue, Field,
1572                                   BaseQuals.getCVRQualifiers());
1573    LV.setNonGC(isNonGC);
1574    setObjCGCLValueClass(getContext(), E, LV);
1575    return LV;
1576  }
1577
1578  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1579    return EmitGlobalVarDeclLValue(*this, E, VD);
1580
1581  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1582    return EmitFunctionDeclLValue(*this, E, FD);
1583
1584  assert(false && "Unhandled member declaration!");
1585  return LValue();
1586}
1587
1588LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
1589                                              const FieldDecl *Field,
1590                                              unsigned CVRQualifiers) {
1591  const CGRecordLayout &RL =
1592    CGM.getTypes().getCGRecordLayout(Field->getParent());
1593  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1594  return LValue::MakeBitfield(BaseValue, Info,
1595                             Field->getType().getCVRQualifiers()|CVRQualifiers);
1596}
1597
1598/// EmitLValueForAnonRecordField - Given that the field is a member of
1599/// an anonymous struct or union buried inside a record, and given
1600/// that the base value is a pointer to the enclosing record, derive
1601/// an lvalue for the ultimate field.
1602LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
1603                                             const IndirectFieldDecl *Field,
1604                                                     unsigned CVRQualifiers) {
1605  IndirectFieldDecl::chain_iterator I = Field->chain_begin(),
1606    IEnd = Field->chain_end();
1607  while (true) {
1608    LValue LV = EmitLValueForField(BaseValue, cast<FieldDecl>(*I), CVRQualifiers);
1609    if (++I == IEnd) return LV;
1610
1611    assert(LV.isSimple());
1612    BaseValue = LV.getAddress();
1613    CVRQualifiers |= LV.getVRQualifiers();
1614  }
1615}
1616
1617LValue CodeGenFunction::EmitLValueForField(llvm::Value *BaseValue,
1618                                           const FieldDecl *Field,
1619                                           unsigned CVRQualifiers) {
1620  if (Field->isBitField())
1621    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1622
1623  const CGRecordLayout &RL =
1624    CGM.getTypes().getCGRecordLayout(Field->getParent());
1625  unsigned idx = RL.getLLVMFieldNo(Field);
1626  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1627
1628  // Match union field type.
1629  if (Field->getParent()->isUnion()) {
1630    const llvm::Type *FieldTy =
1631      CGM.getTypes().ConvertTypeForMem(Field->getType());
1632    const llvm::PointerType *BaseTy =
1633      cast<llvm::PointerType>(BaseValue->getType());
1634    unsigned AS = BaseTy->getAddressSpace();
1635    V = Builder.CreateBitCast(V,
1636                              llvm::PointerType::get(FieldTy, AS),
1637                              "tmp");
1638  }
1639  if (Field->getType()->isReferenceType())
1640    V = Builder.CreateLoad(V, "tmp");
1641
1642  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1643  LValue LV = MakeAddrLValue(V, Field->getType(), Alignment);
1644  LV.getQuals().addCVRQualifiers(CVRQualifiers);
1645
1646  // __weak attribute on a field is ignored.
1647  if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
1648    LV.getQuals().removeObjCGCAttr();
1649
1650  return LV;
1651}
1652
1653LValue
1654CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value *BaseValue,
1655                                                  const FieldDecl *Field,
1656                                                  unsigned CVRQualifiers) {
1657  QualType FieldType = Field->getType();
1658
1659  if (!FieldType->isReferenceType())
1660    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1661
1662  const CGRecordLayout &RL =
1663    CGM.getTypes().getCGRecordLayout(Field->getParent());
1664  unsigned idx = RL.getLLVMFieldNo(Field);
1665  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1666
1667  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1668
1669  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1670  return MakeAddrLValue(V, FieldType, Alignment);
1671}
1672
1673LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
1674  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1675  const Expr *InitExpr = E->getInitializer();
1676  LValue Result = MakeAddrLValue(DeclPtr, E->getType());
1677
1678  EmitAnyExprToMem(InitExpr, DeclPtr, /*Volatile*/ false, /*Init*/ true);
1679
1680  return Result;
1681}
1682
1683LValue
1684CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator *E) {
1685  if (E->isGLValue()) {
1686    if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1687      Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1688      if (Live)
1689        return EmitLValue(Live);
1690    }
1691
1692    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1693    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1694    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1695
1696    if (E->getLHS())
1697      EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1698    else {
1699      Expr *save = E->getSAVE();
1700      assert(save && "VisitConditionalOperator - save is null");
1701      // Intentianlly not doing direct assignment to ConditionalSaveExprs[save]
1702      LValue SaveVal = EmitLValue(save);
1703      ConditionalSaveLValueExprs[save] = SaveVal;
1704      EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1705    }
1706
1707    // Any temporaries created here are conditional.
1708    BeginConditionalBranch();
1709    EmitBlock(LHSBlock);
1710    LValue LHS = EmitLValue(E->getTrueExpr());
1711
1712    EndConditionalBranch();
1713
1714    if (!LHS.isSimple())
1715      return EmitUnsupportedLValue(E, "conditional operator");
1716
1717    // FIXME: We shouldn't need an alloca for this.
1718    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1719    Builder.CreateStore(LHS.getAddress(), Temp);
1720    EmitBranch(ContBlock);
1721
1722    // Any temporaries created here are conditional.
1723    BeginConditionalBranch();
1724    EmitBlock(RHSBlock);
1725    LValue RHS = EmitLValue(E->getRHS());
1726    EndConditionalBranch();
1727    if (!RHS.isSimple())
1728      return EmitUnsupportedLValue(E, "conditional operator");
1729
1730    Builder.CreateStore(RHS.getAddress(), Temp);
1731    EmitBranch(ContBlock);
1732
1733    EmitBlock(ContBlock);
1734
1735    Temp = Builder.CreateLoad(Temp, "lv");
1736    return MakeAddrLValue(Temp, E->getType());
1737  }
1738
1739  // ?: here should be an aggregate.
1740  assert((hasAggregateLLVMType(E->getType()) &&
1741          !E->getType()->isAnyComplexType()) &&
1742         "Unexpected conditional operator!");
1743
1744  return EmitAggExprToLValue(E);
1745}
1746
1747/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1748/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1749/// otherwise if a cast is needed by the code generator in an lvalue context,
1750/// then it must mean that we need the address of an aggregate in order to
1751/// access one of its fields.  This can happen for all the reasons that casts
1752/// are permitted with aggregate result, including noop aggregate casts, and
1753/// cast from scalar to union.
1754LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1755  switch (E->getCastKind()) {
1756  case CK_ToVoid:
1757    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1758
1759  case CK_Dependent:
1760    llvm_unreachable("dependent cast kind in IR gen!");
1761
1762  case CK_GetObjCProperty: {
1763    LValue LV = EmitLValue(E->getSubExpr());
1764    assert(LV.isPropertyRef());
1765    RValue RV = EmitLoadOfPropertyRefLValue(LV);
1766
1767    // Property is an aggregate r-value.
1768    if (RV.isAggregate()) {
1769      return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
1770    }
1771
1772    // Implicit property returns an l-value.
1773    assert(RV.isScalar());
1774    return MakeAddrLValue(RV.getScalarVal(), E->getSubExpr()->getType());
1775  }
1776
1777  case CK_NoOp:
1778    if (!E->getSubExpr()->isRValue() || E->getType()->isRecordType())
1779      return EmitLValue(E->getSubExpr());
1780    // Fall through to synthesize a temporary.
1781
1782  case CK_LValueToRValue:
1783  case CK_BitCast:
1784  case CK_ArrayToPointerDecay:
1785  case CK_FunctionToPointerDecay:
1786  case CK_NullToMemberPointer:
1787  case CK_NullToPointer:
1788  case CK_IntegralToPointer:
1789  case CK_PointerToIntegral:
1790  case CK_PointerToBoolean:
1791  case CK_VectorSplat:
1792  case CK_IntegralCast:
1793  case CK_IntegralToBoolean:
1794  case CK_IntegralToFloating:
1795  case CK_FloatingToIntegral:
1796  case CK_FloatingToBoolean:
1797  case CK_FloatingCast:
1798  case CK_FloatingRealToComplex:
1799  case CK_FloatingComplexToReal:
1800  case CK_FloatingComplexToBoolean:
1801  case CK_FloatingComplexCast:
1802  case CK_FloatingComplexToIntegralComplex:
1803  case CK_IntegralRealToComplex:
1804  case CK_IntegralComplexToReal:
1805  case CK_IntegralComplexToBoolean:
1806  case CK_IntegralComplexCast:
1807  case CK_IntegralComplexToFloatingComplex:
1808  case CK_DerivedToBaseMemberPointer:
1809  case CK_BaseToDerivedMemberPointer:
1810  case CK_MemberPointerToBoolean:
1811  case CK_AnyPointerToBlockPointerCast: {
1812    // These casts only produce lvalues when we're binding a reference to a
1813    // temporary realized from a (converted) pure rvalue. Emit the expression
1814    // as a value, copy it into a temporary, and return an lvalue referring to
1815    // that temporary.
1816    llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
1817    EmitAnyExprToMem(E, V, false, false);
1818    return MakeAddrLValue(V, E->getType());
1819  }
1820
1821  case CK_Dynamic: {
1822    LValue LV = EmitLValue(E->getSubExpr());
1823    llvm::Value *V = LV.getAddress();
1824    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1825    return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
1826  }
1827
1828  case CK_ConstructorConversion:
1829  case CK_UserDefinedConversion:
1830  case CK_AnyPointerToObjCPointerCast:
1831    return EmitLValue(E->getSubExpr());
1832
1833  case CK_UncheckedDerivedToBase:
1834  case CK_DerivedToBase: {
1835    const RecordType *DerivedClassTy =
1836      E->getSubExpr()->getType()->getAs<RecordType>();
1837    CXXRecordDecl *DerivedClassDecl =
1838      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1839
1840    LValue LV = EmitLValue(E->getSubExpr());
1841    llvm::Value *This = LV.getAddress();
1842
1843    // Perform the derived-to-base conversion
1844    llvm::Value *Base =
1845      GetAddressOfBaseClass(This, DerivedClassDecl,
1846                            E->path_begin(), E->path_end(),
1847                            /*NullCheckValue=*/false);
1848
1849    return MakeAddrLValue(Base, E->getType());
1850  }
1851  case CK_ToUnion:
1852    return EmitAggExprToLValue(E);
1853  case CK_BaseToDerived: {
1854    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1855    CXXRecordDecl *DerivedClassDecl =
1856      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1857
1858    LValue LV = EmitLValue(E->getSubExpr());
1859
1860    // Perform the base-to-derived conversion
1861    llvm::Value *Derived =
1862      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
1863                               E->path_begin(), E->path_end(),
1864                               /*NullCheckValue=*/false);
1865
1866    return MakeAddrLValue(Derived, E->getType());
1867  }
1868  case CK_LValueBitCast: {
1869    // This must be a reinterpret_cast (or c-style equivalent).
1870    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1871
1872    LValue LV = EmitLValue(E->getSubExpr());
1873    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1874                                           ConvertType(CE->getTypeAsWritten()));
1875    return MakeAddrLValue(V, E->getType());
1876  }
1877  case CK_ObjCObjectLValueCast: {
1878    LValue LV = EmitLValue(E->getSubExpr());
1879    QualType ToType = getContext().getLValueReferenceType(E->getType());
1880    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1881                                           ConvertType(ToType));
1882    return MakeAddrLValue(V, E->getType());
1883  }
1884  }
1885
1886  llvm_unreachable("Unhandled lvalue cast kind?");
1887}
1888
1889LValue CodeGenFunction::EmitNullInitializationLValue(
1890                                              const CXXScalarValueInitExpr *E) {
1891  QualType Ty = E->getType();
1892  LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
1893  EmitNullInitialization(LV.getAddress(), Ty);
1894  return LV;
1895}
1896
1897//===--------------------------------------------------------------------===//
1898//                             Expression Emission
1899//===--------------------------------------------------------------------===//
1900
1901
1902RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1903                                     ReturnValueSlot ReturnValue) {
1904  // Builtins never have block type.
1905  if (E->getCallee()->getType()->isBlockPointerType())
1906    return EmitBlockCallExpr(E, ReturnValue);
1907
1908  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1909    return EmitCXXMemberCallExpr(CE, ReturnValue);
1910
1911  const Decl *TargetDecl = 0;
1912  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1913    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1914      TargetDecl = DRE->getDecl();
1915      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1916        if (unsigned builtinID = FD->getBuiltinID())
1917          return EmitBuiltinExpr(FD, builtinID, E);
1918    }
1919  }
1920
1921  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1922    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1923      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1924
1925  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1926    // C++ [expr.pseudo]p1:
1927    //   The result shall only be used as the operand for the function call
1928    //   operator (), and the result of such a call has type void. The only
1929    //   effect is the evaluation of the postfix-expression before the dot or
1930    //   arrow.
1931    EmitScalarExpr(E->getCallee());
1932    return RValue::get(0);
1933  }
1934
1935  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1936  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1937                  E->arg_begin(), E->arg_end(), TargetDecl);
1938}
1939
1940LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1941  // Comma expressions just emit their LHS then their RHS as an l-value.
1942  if (E->getOpcode() == BO_Comma) {
1943    EmitIgnoredExpr(E->getLHS());
1944    EnsureInsertPoint();
1945    return EmitLValue(E->getRHS());
1946  }
1947
1948  if (E->getOpcode() == BO_PtrMemD ||
1949      E->getOpcode() == BO_PtrMemI)
1950    return EmitPointerToDataMemberBinaryExpr(E);
1951
1952  assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
1953
1954  if (!hasAggregateLLVMType(E->getType())) {
1955    // __block variables need the RHS evaluated first.
1956    RValue RV = EmitAnyExpr(E->getRHS());
1957    LValue LV = EmitLValue(E->getLHS());
1958    EmitStoreThroughLValue(RV, LV, E->getType());
1959    return LV;
1960  }
1961
1962  if (E->getType()->isAnyComplexType())
1963    return EmitComplexAssignmentLValue(E);
1964
1965  return EmitAggExprToLValue(E);
1966}
1967
1968LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1969  RValue RV = EmitCallExpr(E);
1970
1971  if (!RV.isScalar())
1972    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
1973
1974  assert(E->getCallReturnType()->isReferenceType() &&
1975         "Can't have a scalar return unless the return type is a "
1976         "reference type!");
1977
1978  return MakeAddrLValue(RV.getScalarVal(), E->getType());
1979}
1980
1981LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1982  // FIXME: This shouldn't require another copy.
1983  return EmitAggExprToLValue(E);
1984}
1985
1986LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1987  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
1988         && "binding l-value to type which needs a temporary");
1989  AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
1990  EmitCXXConstructExpr(E, Slot);
1991  return MakeAddrLValue(Slot.getAddr(), E->getType());
1992}
1993
1994LValue
1995CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1996  return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
1997}
1998
1999LValue
2000CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
2001  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
2002  Slot.setLifetimeExternallyManaged();
2003  EmitAggExpr(E->getSubExpr(), Slot);
2004  EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
2005  return MakeAddrLValue(Slot.getAddr(), E->getType());
2006}
2007
2008LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
2009  RValue RV = EmitObjCMessageExpr(E);
2010
2011  if (!RV.isScalar())
2012    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2013
2014  assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
2015         "Can't have a scalar return unless the return type is a "
2016         "reference type!");
2017
2018  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2019}
2020
2021LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
2022  llvm::Value *V =
2023    CGM.getObjCRuntime().GetSelector(Builder, E->getSelector(), true);
2024  return MakeAddrLValue(V, E->getType());
2025}
2026
2027llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
2028                                             const ObjCIvarDecl *Ivar) {
2029  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
2030}
2031
2032LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
2033                                          llvm::Value *BaseValue,
2034                                          const ObjCIvarDecl *Ivar,
2035                                          unsigned CVRQualifiers) {
2036  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
2037                                                   Ivar, CVRQualifiers);
2038}
2039
2040LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
2041  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
2042  llvm::Value *BaseValue = 0;
2043  const Expr *BaseExpr = E->getBase();
2044  Qualifiers BaseQuals;
2045  QualType ObjectTy;
2046  if (E->isArrow()) {
2047    BaseValue = EmitScalarExpr(BaseExpr);
2048    ObjectTy = BaseExpr->getType()->getPointeeType();
2049    BaseQuals = ObjectTy.getQualifiers();
2050  } else {
2051    LValue BaseLV = EmitLValue(BaseExpr);
2052    // FIXME: this isn't right for bitfields.
2053    BaseValue = BaseLV.getAddress();
2054    ObjectTy = BaseExpr->getType();
2055    BaseQuals = ObjectTy.getQualifiers();
2056  }
2057
2058  LValue LV =
2059    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
2060                      BaseQuals.getCVRQualifiers());
2061  setObjCGCLValueClass(getContext(), E, LV);
2062  return LV;
2063}
2064
2065LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
2066  // Can only get l-value for message expression returning aggregate type
2067  RValue RV = EmitAnyExprToTemp(E);
2068  return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2069}
2070
2071RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
2072                                 ReturnValueSlot ReturnValue,
2073                                 CallExpr::const_arg_iterator ArgBeg,
2074                                 CallExpr::const_arg_iterator ArgEnd,
2075                                 const Decl *TargetDecl) {
2076  // Get the actual function type. The callee type will always be a pointer to
2077  // function type or a block pointer type.
2078  assert(CalleeType->isFunctionPointerType() &&
2079         "Call must have function pointer type!");
2080
2081  CalleeType = getContext().getCanonicalType(CalleeType);
2082
2083  const FunctionType *FnType
2084    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
2085
2086  CallArgList Args;
2087  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
2088
2089  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
2090                  Callee, ReturnValue, Args, TargetDecl);
2091}
2092
2093LValue CodeGenFunction::
2094EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
2095  llvm::Value *BaseV;
2096  if (E->getOpcode() == BO_PtrMemI)
2097    BaseV = EmitScalarExpr(E->getLHS());
2098  else
2099    BaseV = EmitLValue(E->getLHS()).getAddress();
2100
2101  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
2102
2103  const MemberPointerType *MPT
2104    = E->getRHS()->getType()->getAs<MemberPointerType>();
2105
2106  llvm::Value *AddV =
2107    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
2108
2109  return MakeAddrLValue(AddV, MPT->getPointeeType());
2110}
2111