CGExpr.cpp revision 0e800c9c20d1a658a91096c756c4a4a9e90264fc 
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/// EmitAnyExpr - Emit code to compute the specified expression which
82/// can have any type.  The result is returned as an RValue struct.
83/// If this is an aggregate expression, AggSlot indicates where the
84/// result should be returned.
85RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot AggSlot,
86                                    bool IgnoreResult) {
87  if (!hasAggregateLLVMType(E->getType()))
88    return RValue::get(EmitScalarExpr(E, IgnoreResult));
89  else if (E->getType()->isAnyComplexType())
90    return RValue::getComplex(EmitComplexExpr(E, IgnoreResult, IgnoreResult));
91
92  EmitAggExpr(E, AggSlot, IgnoreResult);
93  return AggSlot.asRValue();
94}
95
96/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
97/// always be accessible even if no aggregate location is provided.
98RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
99  AggValueSlot AggSlot = AggValueSlot::ignored();
100
101  if (hasAggregateLLVMType(E->getType()) &&
102      !E->getType()->isAnyComplexType())
103    AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
104  return EmitAnyExpr(E, AggSlot);
105}
106
107/// EmitAnyExprToMem - Evaluate an expression into a given memory
108/// location.
109void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
110                                       llvm::Value *Location,
111                                       bool IsLocationVolatile,
112                                       bool IsInit) {
113  if (E->getType()->isComplexType())
114    EmitComplexExprIntoAddr(E, Location, IsLocationVolatile);
115  else if (hasAggregateLLVMType(E->getType()))
116    EmitAggExpr(E, AggValueSlot::forAddr(Location, IsLocationVolatile, IsInit));
117  else {
118    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
119    LValue LV = MakeAddrLValue(Location, E->getType());
120    EmitStoreThroughLValue(RV, LV, E->getType());
121  }
122}
123
124namespace {
125/// \brief An adjustment to be made to the temporary created when emitting a
126/// reference binding, which accesses a particular subobject of that temporary.
127  struct SubobjectAdjustment {
128    enum { DerivedToBaseAdjustment, FieldAdjustment } Kind;
129
130    union {
131      struct {
132        const CastExpr *BasePath;
133        const CXXRecordDecl *DerivedClass;
134      } DerivedToBase;
135
136      FieldDecl *Field;
137    };
138
139    SubobjectAdjustment(const CastExpr *BasePath,
140                        const CXXRecordDecl *DerivedClass)
141      : Kind(DerivedToBaseAdjustment) {
142      DerivedToBase.BasePath = BasePath;
143      DerivedToBase.DerivedClass = DerivedClass;
144    }
145
146    SubobjectAdjustment(FieldDecl *Field)
147      : Kind(FieldAdjustment) {
148      this->Field = Field;
149    }
150  };
151}
152
153static llvm::Value *
154CreateReferenceTemporary(CodeGenFunction& CGF, QualType Type,
155                         const NamedDecl *InitializedDecl) {
156  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
157    if (VD->hasGlobalStorage()) {
158      llvm::SmallString<256> Name;
159      CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Name);
160
161      const llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
162
163      // Create the reference temporary.
164      llvm::GlobalValue *RefTemp =
165        new llvm::GlobalVariable(CGF.CGM.getModule(),
166                                 RefTempTy, /*isConstant=*/false,
167                                 llvm::GlobalValue::InternalLinkage,
168                                 llvm::Constant::getNullValue(RefTempTy),
169                                 Name.str());
170      return RefTemp;
171    }
172  }
173
174  return CGF.CreateMemTemp(Type, "ref.tmp");
175}
176
177static llvm::Value *
178EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
179                            llvm::Value *&ReferenceTemporary,
180                            const CXXDestructorDecl *&ReferenceTemporaryDtor,
181                            const NamedDecl *InitializedDecl) {
182  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
183    E = DAE->getExpr();
184
185  if (const CXXExprWithTemporaries *TE = dyn_cast<CXXExprWithTemporaries>(E)) {
186    CodeGenFunction::RunCleanupsScope Scope(CGF);
187
188    return EmitExprForReferenceBinding(CGF, TE->getSubExpr(),
189                                       ReferenceTemporary,
190                                       ReferenceTemporaryDtor,
191                                       InitializedDecl);
192  }
193
194  RValue RV;
195  if (E->isLValue()) {
196    // Emit the expression as an lvalue.
197    LValue LV = CGF.EmitLValue(E);
198    if (LV.isSimple())
199      return LV.getAddress();
200
201    // We have to load the lvalue.
202    RV = CGF.EmitLoadOfLValue(LV, E->getType());
203  } else {
204    QualType ResultTy = E->getType();
205
206    llvm::SmallVector<SubobjectAdjustment, 2> Adjustments;
207    while (true) {
208      if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
209        E = PE->getSubExpr();
210        continue;
211      }
212
213      if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
214        if ((CE->getCastKind() == CK_DerivedToBase ||
215             CE->getCastKind() == CK_UncheckedDerivedToBase) &&
216            E->getType()->isRecordType()) {
217          E = CE->getSubExpr();
218          CXXRecordDecl *Derived
219            = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
220          Adjustments.push_back(SubobjectAdjustment(CE, Derived));
221          continue;
222        }
223
224        if (CE->getCastKind() == CK_NoOp) {
225          E = CE->getSubExpr();
226          continue;
227        }
228      } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
229        if (!ME->isArrow() && ME->getBase()->isRValue()) {
230          assert(ME->getBase()->getType()->isRecordType());
231          if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
232            E = ME->getBase();
233            Adjustments.push_back(SubobjectAdjustment(Field));
234            continue;
235          }
236        }
237      }
238
239      // Nothing changed.
240      break;
241    }
242
243    // Create a reference temporary if necessary.
244    AggValueSlot AggSlot = AggValueSlot::ignored();
245    if (CGF.hasAggregateLLVMType(E->getType()) &&
246        !E->getType()->isAnyComplexType()) {
247      ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
248                                                    InitializedDecl);
249      AggSlot = AggValueSlot::forAddr(ReferenceTemporary, false,
250                                      InitializedDecl != 0);
251    }
252
253    RV = CGF.EmitAnyExpr(E, AggSlot);
254
255    if (InitializedDecl) {
256      // Get the destructor for the reference temporary.
257      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
258        CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
259        if (!ClassDecl->hasTrivialDestructor())
260          ReferenceTemporaryDtor = ClassDecl->getDestructor();
261      }
262    }
263
264    // Check if need to perform derived-to-base casts and/or field accesses, to
265    // get from the temporary object we created (and, potentially, for which we
266    // extended the lifetime) to the subobject we're binding the reference to.
267    if (!Adjustments.empty()) {
268      llvm::Value *Object = RV.getAggregateAddr();
269      for (unsigned I = Adjustments.size(); I != 0; --I) {
270        SubobjectAdjustment &Adjustment = Adjustments[I-1];
271        switch (Adjustment.Kind) {
272        case SubobjectAdjustment::DerivedToBaseAdjustment:
273          Object =
274              CGF.GetAddressOfBaseClass(Object,
275                                        Adjustment.DerivedToBase.DerivedClass,
276                              Adjustment.DerivedToBase.BasePath->path_begin(),
277                              Adjustment.DerivedToBase.BasePath->path_end(),
278                                        /*NullCheckValue=*/false);
279          break;
280
281        case SubobjectAdjustment::FieldAdjustment: {
282          LValue LV =
283            CGF.EmitLValueForField(Object, Adjustment.Field, 0);
284          if (LV.isSimple()) {
285            Object = LV.getAddress();
286            break;
287          }
288
289          // For non-simple lvalues, we actually have to create a copy of
290          // the object we're binding to.
291          QualType T = Adjustment.Field->getType().getNonReferenceType()
292                                                  .getUnqualifiedType();
293          Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
294          LValue TempLV = CGF.MakeAddrLValue(Object,
295                                             Adjustment.Field->getType());
296          CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV, T), TempLV, T);
297          break;
298        }
299
300        }
301      }
302
303      const llvm::Type *ResultPtrTy = CGF.ConvertType(ResultTy)->getPointerTo();
304      return CGF.Builder.CreateBitCast(Object, ResultPtrTy, "temp");
305    }
306  }
307
308  if (RV.isAggregate())
309    return RV.getAggregateAddr();
310
311  // Create a temporary variable that we can bind the reference to.
312  ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
313                                                InitializedDecl);
314
315
316  unsigned Alignment =
317    CGF.getContext().getTypeAlignInChars(E->getType()).getQuantity();
318  if (RV.isScalar())
319    CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
320                          /*Volatile=*/false, Alignment, E->getType());
321  else
322    CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
323                           /*Volatile=*/false);
324  return ReferenceTemporary;
325}
326
327RValue
328CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
329                                            const NamedDecl *InitializedDecl) {
330  llvm::Value *ReferenceTemporary = 0;
331  const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
332  llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
333                                                   ReferenceTemporaryDtor,
334                                                   InitializedDecl);
335  if (!ReferenceTemporaryDtor)
336    return RValue::get(Value);
337
338  // Make sure to call the destructor for the reference temporary.
339  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
340    if (VD->hasGlobalStorage()) {
341      llvm::Constant *DtorFn =
342        CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
343      CGF.EmitCXXGlobalDtorRegistration(DtorFn,
344                                      cast<llvm::Constant>(ReferenceTemporary));
345
346      return RValue::get(Value);
347    }
348  }
349
350  PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
351
352  return RValue::get(Value);
353}
354
355
356/// getAccessedFieldNo - Given an encoded value and a result number, return the
357/// input field number being accessed.
358unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
359                                             const llvm::Constant *Elts) {
360  if (isa<llvm::ConstantAggregateZero>(Elts))
361    return 0;
362
363  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
364}
365
366void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
367  if (!CatchUndefined)
368    return;
369
370  Address = Builder.CreateBitCast(Address, PtrToInt8Ty);
371
372  const llvm::Type *IntPtrT = IntPtrTy;
373  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, &IntPtrT, 1);
374  const llvm::IntegerType *Int1Ty = llvm::Type::getInt1Ty(VMContext);
375
376  // In time, people may want to control this and use a 1 here.
377  llvm::Value *Arg = llvm::ConstantInt::get(Int1Ty, 0);
378  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
379  llvm::BasicBlock *Cont = createBasicBlock();
380  llvm::BasicBlock *Check = createBasicBlock();
381  llvm::Value *NegativeOne = llvm::ConstantInt::get(IntPtrTy, -1ULL);
382  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
383
384  EmitBlock(Check);
385  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
386                                        llvm::ConstantInt::get(IntPtrTy, Size)),
387                       Cont, getTrapBB());
388  EmitBlock(Cont);
389}
390
391
392CodeGenFunction::ComplexPairTy CodeGenFunction::
393EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
394                         bool isInc, bool isPre) {
395  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
396                                            LV.isVolatileQualified());
397
398  llvm::Value *NextVal;
399  if (isa<llvm::IntegerType>(InVal.first->getType())) {
400    uint64_t AmountVal = isInc ? 1 : -1;
401    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
402
403    // Add the inc/dec to the real part.
404    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
405  } else {
406    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
407    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
408    if (!isInc)
409      FVal.changeSign();
410    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
411
412    // Add the inc/dec to the real part.
413    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
414  }
415
416  ComplexPairTy IncVal(NextVal, InVal.second);
417
418  // Store the updated result through the lvalue.
419  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
420
421  // If this is a postinc, return the value read from memory, otherwise use the
422  // updated value.
423  return isPre ? IncVal : InVal;
424}
425
426
427//===----------------------------------------------------------------------===//
428//                         LValue Expression Emission
429//===----------------------------------------------------------------------===//
430
431RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
432  if (Ty->isVoidType())
433    return RValue::get(0);
434
435  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
436    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
437    llvm::Value *U = llvm::UndefValue::get(EltTy);
438    return RValue::getComplex(std::make_pair(U, U));
439  }
440
441  // If this is a use of an undefined aggregate type, the aggregate must have an
442  // identifiable address.  Just because the contents of the value are undefined
443  // doesn't mean that the address can't be taken and compared.
444  if (hasAggregateLLVMType(Ty)) {
445    llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
446    return RValue::getAggregate(DestPtr);
447  }
448
449  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
450}
451
452RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
453                                              const char *Name) {
454  ErrorUnsupported(E, Name);
455  return GetUndefRValue(E->getType());
456}
457
458LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
459                                              const char *Name) {
460  ErrorUnsupported(E, Name);
461  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
462  return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
463}
464
465LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
466  LValue LV = EmitLValue(E);
467  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
468    EmitCheck(LV.getAddress(), getContext().getTypeSize(E->getType()) / 8);
469  return LV;
470}
471
472/// EmitLValue - Emit code to compute a designator that specifies the location
473/// of the expression.
474///
475/// This can return one of two things: a simple address or a bitfield reference.
476/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
477/// an LLVM pointer type.
478///
479/// If this returns a bitfield reference, nothing about the pointee type of the
480/// LLVM value is known: For example, it may not be a pointer to an integer.
481///
482/// If this returns a normal address, and if the lvalue's C type is fixed size,
483/// this method guarantees that the returned pointer type will point to an LLVM
484/// type of the same size of the lvalue's type.  If the lvalue has a variable
485/// length type, this is not possible.
486///
487LValue CodeGenFunction::EmitLValue(const Expr *E) {
488  llvm::DenseMap<const Expr *, LValue>::iterator I =
489                                      CGF.ConditionalSaveLValueExprs.find(E);
490  if (I != CGF.ConditionalSaveLValueExprs.end())
491    return I->second;
492
493  switch (E->getStmtClass()) {
494  default: return EmitUnsupportedLValue(E, "l-value expression");
495
496  case Expr::ObjCSelectorExprClass:
497  return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
498  case Expr::ObjCIsaExprClass:
499    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
500  case Expr::BinaryOperatorClass:
501    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
502  case Expr::CompoundAssignOperatorClass:
503    return EmitCompoundAssignOperatorLValue(cast<CompoundAssignOperator>(E));
504  case Expr::CallExprClass:
505  case Expr::CXXMemberCallExprClass:
506  case Expr::CXXOperatorCallExprClass:
507    return EmitCallExprLValue(cast<CallExpr>(E));
508  case Expr::VAArgExprClass:
509    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
510  case Expr::DeclRefExprClass:
511    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
512  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
513  case Expr::PredefinedExprClass:
514    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
515  case Expr::StringLiteralClass:
516    return EmitStringLiteralLValue(cast<StringLiteral>(E));
517  case Expr::ObjCEncodeExprClass:
518    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
519
520  case Expr::BlockDeclRefExprClass:
521    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
522
523  case Expr::CXXTemporaryObjectExprClass:
524  case Expr::CXXConstructExprClass:
525    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
526  case Expr::CXXBindTemporaryExprClass:
527    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
528  case Expr::CXXExprWithTemporariesClass:
529    return EmitCXXExprWithTemporariesLValue(cast<CXXExprWithTemporaries>(E));
530  case Expr::CXXScalarValueInitExprClass:
531    return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
532  case Expr::CXXDefaultArgExprClass:
533    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
534  case Expr::CXXTypeidExprClass:
535    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
536
537  case Expr::ObjCMessageExprClass:
538    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
539  case Expr::ObjCIvarRefExprClass:
540    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
541  case Expr::ObjCPropertyRefExprClass:
542    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
543  case Expr::StmtExprClass:
544    return EmitStmtExprLValue(cast<StmtExpr>(E));
545  case Expr::UnaryOperatorClass:
546    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
547  case Expr::ArraySubscriptExprClass:
548    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
549  case Expr::ExtVectorElementExprClass:
550    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
551  case Expr::MemberExprClass:
552    return EmitMemberExpr(cast<MemberExpr>(E));
553  case Expr::CompoundLiteralExprClass:
554    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
555  case Expr::ConditionalOperatorClass:
556    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
557  case Expr::ChooseExprClass:
558    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
559  case Expr::ImplicitCastExprClass:
560  case Expr::CStyleCastExprClass:
561  case Expr::CXXFunctionalCastExprClass:
562  case Expr::CXXStaticCastExprClass:
563  case Expr::CXXDynamicCastExprClass:
564  case Expr::CXXReinterpretCastExprClass:
565  case Expr::CXXConstCastExprClass:
566    return EmitCastLValue(cast<CastExpr>(E));
567  }
568}
569
570llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
571                                              unsigned Alignment, QualType Ty,
572                                              llvm::MDNode *TBAAInfo) {
573  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
574  if (Volatile)
575    Load->setVolatile(true);
576  if (Alignment)
577    Load->setAlignment(Alignment);
578  if (TBAAInfo)
579    CGM.DecorateInstruction(Load, TBAAInfo);
580
581  return EmitFromMemory(Load, Ty);
582}
583
584static bool isBooleanUnderlyingType(QualType Ty) {
585  if (const EnumType *ET = dyn_cast<EnumType>(Ty))
586    return ET->getDecl()->getIntegerType()->isBooleanType();
587  return false;
588}
589
590llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
591  // Bool has a different representation in memory than in registers.
592  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
593    // This should really always be an i1, but sometimes it's already
594    // an i8, and it's awkward to track those cases down.
595    if (Value->getType()->isIntegerTy(1))
596      return Builder.CreateZExt(Value, Builder.getInt8Ty(), "frombool");
597    assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
598  }
599
600  return Value;
601}
602
603llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
604  // Bool has a different representation in memory than in registers.
605  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
606    assert(Value->getType()->isIntegerTy(8) && "memory rep of bool not i8");
607    return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
608  }
609
610  return Value;
611}
612
613void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
614                                        bool Volatile, unsigned Alignment,
615                                        QualType Ty,
616                                        llvm::MDNode *TBAAInfo) {
617  Value = EmitToMemory(Value, Ty);
618  llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
619  if (Alignment)
620    Store->setAlignment(Alignment);
621  if (TBAAInfo)
622    CGM.DecorateInstruction(Store, TBAAInfo);
623}
624
625/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
626/// method emits the address of the lvalue, then loads the result as an rvalue,
627/// returning the rvalue.
628RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
629  if (LV.isObjCWeak()) {
630    // load of a __weak object.
631    llvm::Value *AddrWeakObj = LV.getAddress();
632    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
633                                                             AddrWeakObj));
634  }
635
636  if (LV.isSimple()) {
637    llvm::Value *Ptr = LV.getAddress();
638
639    // Functions are l-values that don't require loading.
640    if (ExprType->isFunctionType())
641      return RValue::get(Ptr);
642
643    // Everything needs a load.
644    return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
645                                        LV.getAlignment(), ExprType,
646                                        LV.getTBAAInfo()));
647
648  }
649
650  if (LV.isVectorElt()) {
651    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
652                                          LV.isVolatileQualified(), "tmp");
653    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
654                                                    "vecext"));
655  }
656
657  // If this is a reference to a subset of the elements of a vector, either
658  // shuffle the input or extract/insert them as appropriate.
659  if (LV.isExtVectorElt())
660    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
661
662  if (LV.isBitField())
663    return EmitLoadOfBitfieldLValue(LV, ExprType);
664
665  assert(LV.isPropertyRef() && "Unknown LValue type!");
666  return EmitLoadOfPropertyRefLValue(LV);
667}
668
669RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
670                                                 QualType ExprType) {
671  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
672
673  // Get the output type.
674  const llvm::Type *ResLTy = ConvertType(ExprType);
675  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
676
677  // Compute the result as an OR of all of the individual component accesses.
678  llvm::Value *Res = 0;
679  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
680    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
681
682    // Get the field pointer.
683    llvm::Value *Ptr = LV.getBitFieldBaseAddr();
684
685    // Only offset by the field index if used, so that incoming values are not
686    // required to be structures.
687    if (AI.FieldIndex)
688      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
689
690    // Offset by the byte offset, if used.
691    if (AI.FieldByteOffset) {
692      const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
693      Ptr = Builder.CreateBitCast(Ptr, i8PTy);
694      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
695    }
696
697    // Cast to the access type.
698    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(VMContext, AI.AccessWidth,
699                                                    ExprType.getAddressSpace());
700    Ptr = Builder.CreateBitCast(Ptr, PTy);
701
702    // Perform the load.
703    llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
704    if (AI.AccessAlignment)
705      Load->setAlignment(AI.AccessAlignment);
706
707    // Shift out unused low bits and mask out unused high bits.
708    llvm::Value *Val = Load;
709    if (AI.FieldBitStart)
710      Val = Builder.CreateLShr(Load, AI.FieldBitStart);
711    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
712                                                            AI.TargetBitWidth),
713                            "bf.clear");
714
715    // Extend or truncate to the target size.
716    if (AI.AccessWidth < ResSizeInBits)
717      Val = Builder.CreateZExt(Val, ResLTy);
718    else if (AI.AccessWidth > ResSizeInBits)
719      Val = Builder.CreateTrunc(Val, ResLTy);
720
721    // Shift into place, and OR into the result.
722    if (AI.TargetBitOffset)
723      Val = Builder.CreateShl(Val, AI.TargetBitOffset);
724    Res = Res ? Builder.CreateOr(Res, Val) : Val;
725  }
726
727  // If the bit-field is signed, perform the sign-extension.
728  //
729  // FIXME: This can easily be folded into the load of the high bits, which
730  // could also eliminate the mask of high bits in some situations.
731  if (Info.isSigned()) {
732    unsigned ExtraBits = ResSizeInBits - Info.getSize();
733    if (ExtraBits)
734      Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
735                               ExtraBits, "bf.val.sext");
736  }
737
738  return RValue::get(Res);
739}
740
741// If this is a reference to a subset of the elements of a vector, create an
742// appropriate shufflevector.
743RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
744                                                         QualType ExprType) {
745  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
746                                        LV.isVolatileQualified(), "tmp");
747
748  const llvm::Constant *Elts = LV.getExtVectorElts();
749
750  // If the result of the expression is a non-vector type, we must be extracting
751  // a single element.  Just codegen as an extractelement.
752  const VectorType *ExprVT = ExprType->getAs<VectorType>();
753  if (!ExprVT) {
754    unsigned InIdx = getAccessedFieldNo(0, Elts);
755    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
756    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
757  }
758
759  // Always use shuffle vector to try to retain the original program structure
760  unsigned NumResultElts = ExprVT->getNumElements();
761
762  llvm::SmallVector<llvm::Constant*, 4> Mask;
763  for (unsigned i = 0; i != NumResultElts; ++i) {
764    unsigned InIdx = getAccessedFieldNo(i, Elts);
765    Mask.push_back(llvm::ConstantInt::get(Int32Ty, InIdx));
766  }
767
768  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
769  Vec = Builder.CreateShuffleVector(Vec,
770                                    llvm::UndefValue::get(Vec->getType()),
771                                    MaskV, "tmp");
772  return RValue::get(Vec);
773}
774
775
776
777/// EmitStoreThroughLValue - Store the specified rvalue into the specified
778/// lvalue, where both are guaranteed to the have the same type, and that type
779/// is 'Ty'.
780void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
781                                             QualType Ty) {
782  if (!Dst.isSimple()) {
783    if (Dst.isVectorElt()) {
784      // Read/modify/write the vector, inserting the new element.
785      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
786                                            Dst.isVolatileQualified(), "tmp");
787      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
788                                        Dst.getVectorIdx(), "vecins");
789      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
790      return;
791    }
792
793    // If this is an update of extended vector elements, insert them as
794    // appropriate.
795    if (Dst.isExtVectorElt())
796      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
797
798    if (Dst.isBitField())
799      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
800
801    assert(Dst.isPropertyRef() && "Unknown LValue type");
802    return EmitStoreThroughPropertyRefLValue(Src, Dst);
803  }
804
805  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
806    // load of a __weak object.
807    llvm::Value *LvalueDst = Dst.getAddress();
808    llvm::Value *src = Src.getScalarVal();
809     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
810    return;
811  }
812
813  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
814    // load of a __strong object.
815    llvm::Value *LvalueDst = Dst.getAddress();
816    llvm::Value *src = Src.getScalarVal();
817    if (Dst.isObjCIvar()) {
818      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
819      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
820      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
821      llvm::Value *dst = RHS;
822      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
823      llvm::Value *LHS =
824        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
825      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
826      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
827                                              BytesBetween);
828    } else if (Dst.isGlobalObjCRef()) {
829      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
830                                                Dst.isThreadLocalRef());
831    }
832    else
833      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
834    return;
835  }
836
837  assert(Src.isScalar() && "Can't emit an agg store with this method");
838  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
839                    Dst.isVolatileQualified(), Dst.getAlignment(), Ty,
840                    Dst.getTBAAInfo());
841}
842
843void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
844                                                     QualType Ty,
845                                                     llvm::Value **Result) {
846  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
847
848  // Get the output type.
849  const llvm::Type *ResLTy = ConvertTypeForMem(Ty);
850  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
851
852  // Get the source value, truncated to the width of the bit-field.
853  llvm::Value *SrcVal = Src.getScalarVal();
854
855  if (Ty->isBooleanType())
856    SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
857
858  SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
859                                                                Info.getSize()),
860                             "bf.value");
861
862  // Return the new value of the bit-field, if requested.
863  if (Result) {
864    // Cast back to the proper type for result.
865    const llvm::Type *SrcTy = Src.getScalarVal()->getType();
866    llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
867                                                   "bf.reload.val");
868
869    // Sign extend if necessary.
870    if (Info.isSigned()) {
871      unsigned ExtraBits = ResSizeInBits - Info.getSize();
872      if (ExtraBits)
873        ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
874                                       ExtraBits, "bf.reload.sext");
875    }
876
877    *Result = ReloadVal;
878  }
879
880  // Iterate over the components, writing each piece to memory.
881  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
882    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
883
884    // Get the field pointer.
885    llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
886
887    // Only offset by the field index if used, so that incoming values are not
888    // required to be structures.
889    if (AI.FieldIndex)
890      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
891
892    // Offset by the byte offset, if used.
893    if (AI.FieldByteOffset) {
894      const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
895      Ptr = Builder.CreateBitCast(Ptr, i8PTy);
896      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
897    }
898
899    // Cast to the access type.
900    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(VMContext, AI.AccessWidth,
901                                                     Ty.getAddressSpace());
902    Ptr = Builder.CreateBitCast(Ptr, PTy);
903
904    // Extract the piece of the bit-field value to write in this access, limited
905    // to the values that are part of this access.
906    llvm::Value *Val = SrcVal;
907    if (AI.TargetBitOffset)
908      Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
909    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
910                                                            AI.TargetBitWidth));
911
912    // Extend or truncate to the access size.
913    const llvm::Type *AccessLTy =
914      llvm::Type::getIntNTy(VMContext, AI.AccessWidth);
915    if (ResSizeInBits < AI.AccessWidth)
916      Val = Builder.CreateZExt(Val, AccessLTy);
917    else if (ResSizeInBits > AI.AccessWidth)
918      Val = Builder.CreateTrunc(Val, AccessLTy);
919
920    // Shift into the position in memory.
921    if (AI.FieldBitStart)
922      Val = Builder.CreateShl(Val, AI.FieldBitStart);
923
924    // If necessary, load and OR in bits that are outside of the bit-field.
925    if (AI.TargetBitWidth != AI.AccessWidth) {
926      llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
927      if (AI.AccessAlignment)
928        Load->setAlignment(AI.AccessAlignment);
929
930      // Compute the mask for zeroing the bits that are part of the bit-field.
931      llvm::APInt InvMask =
932        ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
933                                 AI.FieldBitStart + AI.TargetBitWidth);
934
935      // Apply the mask and OR in to the value to write.
936      Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
937    }
938
939    // Write the value.
940    llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
941                                                 Dst.isVolatileQualified());
942    if (AI.AccessAlignment)
943      Store->setAlignment(AI.AccessAlignment);
944  }
945}
946
947void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
948                                                               LValue Dst,
949                                                               QualType Ty) {
950  // This access turns into a read/modify/write of the vector.  Load the input
951  // value now.
952  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
953                                        Dst.isVolatileQualified(), "tmp");
954  const llvm::Constant *Elts = Dst.getExtVectorElts();
955
956  llvm::Value *SrcVal = Src.getScalarVal();
957
958  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
959    unsigned NumSrcElts = VTy->getNumElements();
960    unsigned NumDstElts =
961       cast<llvm::VectorType>(Vec->getType())->getNumElements();
962    if (NumDstElts == NumSrcElts) {
963      // Use shuffle vector is the src and destination are the same number of
964      // elements and restore the vector mask since it is on the side it will be
965      // stored.
966      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
967      for (unsigned i = 0; i != NumSrcElts; ++i) {
968        unsigned InIdx = getAccessedFieldNo(i, Elts);
969        Mask[InIdx] = llvm::ConstantInt::get(Int32Ty, i);
970      }
971
972      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
973      Vec = Builder.CreateShuffleVector(SrcVal,
974                                        llvm::UndefValue::get(Vec->getType()),
975                                        MaskV, "tmp");
976    } else if (NumDstElts > NumSrcElts) {
977      // Extended the source vector to the same length and then shuffle it
978      // into the destination.
979      // FIXME: since we're shuffling with undef, can we just use the indices
980      //        into that?  This could be simpler.
981      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
982      unsigned i;
983      for (i = 0; i != NumSrcElts; ++i)
984        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
985      for (; i != NumDstElts; ++i)
986        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
987      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
988                                                        ExtMask.size());
989      llvm::Value *ExtSrcVal =
990        Builder.CreateShuffleVector(SrcVal,
991                                    llvm::UndefValue::get(SrcVal->getType()),
992                                    ExtMaskV, "tmp");
993      // build identity
994      llvm::SmallVector<llvm::Constant*, 4> Mask;
995      for (unsigned i = 0; i != NumDstElts; ++i)
996        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
997
998      // modify when what gets shuffled in
999      for (unsigned i = 0; i != NumSrcElts; ++i) {
1000        unsigned Idx = getAccessedFieldNo(i, Elts);
1001        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
1002      }
1003      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
1004      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
1005    } else {
1006      // We should never shorten the vector
1007      assert(0 && "unexpected shorten vector length");
1008    }
1009  } else {
1010    // If the Src is a scalar (not a vector) it must be updating one element.
1011    unsigned InIdx = getAccessedFieldNo(0, Elts);
1012    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1013    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
1014  }
1015
1016  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1017}
1018
1019// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1020// generating write-barries API. It is currently a global, ivar,
1021// or neither.
1022static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1023                                 LValue &LV) {
1024  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
1025    return;
1026
1027  if (isa<ObjCIvarRefExpr>(E)) {
1028    LV.setObjCIvar(true);
1029    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1030    LV.setBaseIvarExp(Exp->getBase());
1031    LV.setObjCArray(E->getType()->isArrayType());
1032    return;
1033  }
1034
1035  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1036    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1037      if (VD->hasGlobalStorage()) {
1038        LV.setGlobalObjCRef(true);
1039        LV.setThreadLocalRef(VD->isThreadSpecified());
1040      }
1041    }
1042    LV.setObjCArray(E->getType()->isArrayType());
1043    return;
1044  }
1045
1046  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1047    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1048    return;
1049  }
1050
1051  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1052    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1053    if (LV.isObjCIvar()) {
1054      // If cast is to a structure pointer, follow gcc's behavior and make it
1055      // a non-ivar write-barrier.
1056      QualType ExpTy = E->getType();
1057      if (ExpTy->isPointerType())
1058        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1059      if (ExpTy->isRecordType())
1060        LV.setObjCIvar(false);
1061    }
1062    return;
1063  }
1064  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1065    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1066    return;
1067  }
1068
1069  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1070    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1071    return;
1072  }
1073
1074  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1075    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1076    if (LV.isObjCIvar() && !LV.isObjCArray())
1077      // Using array syntax to assigning to what an ivar points to is not
1078      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1079      LV.setObjCIvar(false);
1080    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1081      // Using array syntax to assigning to what global points to is not
1082      // same as assigning to the global itself. {id *G;} G[i] = 0;
1083      LV.setGlobalObjCRef(false);
1084    return;
1085  }
1086
1087  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1088    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1089    // We don't know if member is an 'ivar', but this flag is looked at
1090    // only in the context of LV.isObjCIvar().
1091    LV.setObjCArray(E->getType()->isArrayType());
1092    return;
1093  }
1094}
1095
1096static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1097                                      const Expr *E, const VarDecl *VD) {
1098  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1099         "Var decl must have external storage or be a file var decl!");
1100
1101  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1102  if (VD->getType()->isReferenceType())
1103    V = CGF.Builder.CreateLoad(V, "tmp");
1104  unsigned Alignment = CGF.getContext().getDeclAlign(VD).getQuantity();
1105  LValue LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1106  setObjCGCLValueClass(CGF.getContext(), E, LV);
1107  return LV;
1108}
1109
1110static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1111                                      const Expr *E, const FunctionDecl *FD) {
1112  llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1113  if (!FD->hasPrototype()) {
1114    if (const FunctionProtoType *Proto =
1115            FD->getType()->getAs<FunctionProtoType>()) {
1116      // Ugly case: for a K&R-style definition, the type of the definition
1117      // isn't the same as the type of a use.  Correct for this with a
1118      // bitcast.
1119      QualType NoProtoType =
1120          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1121      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1122      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1123    }
1124  }
1125  unsigned Alignment = CGF.getContext().getDeclAlign(FD).getQuantity();
1126  return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1127}
1128
1129LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1130  const NamedDecl *ND = E->getDecl();
1131  unsigned Alignment = CGF.getContext().getDeclAlign(ND).getQuantity();
1132
1133  if (ND->hasAttr<WeakRefAttr>()) {
1134    const ValueDecl *VD = cast<ValueDecl>(ND);
1135    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1136    return MakeAddrLValue(Aliasee, E->getType(), Alignment);
1137  }
1138
1139  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1140
1141    // Check if this is a global variable.
1142    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1143      return EmitGlobalVarDeclLValue(*this, E, VD);
1144
1145    bool NonGCable = VD->hasLocalStorage() &&
1146                     !VD->getType()->isReferenceType() &&
1147                     !VD->hasAttr<BlocksAttr>();
1148
1149    llvm::Value *V = LocalDeclMap[VD];
1150    if (!V && VD->isStaticLocal())
1151      V = CGM.getStaticLocalDeclAddress(VD);
1152    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1153
1154    if (VD->hasAttr<BlocksAttr>()) {
1155      V = Builder.CreateStructGEP(V, 1, "forwarding");
1156      V = Builder.CreateLoad(V);
1157      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
1158                                  VD->getNameAsString());
1159    }
1160    if (VD->getType()->isReferenceType())
1161      V = Builder.CreateLoad(V, "tmp");
1162
1163    LValue LV = MakeAddrLValue(V, E->getType(), Alignment);
1164    if (NonGCable) {
1165      LV.getQuals().removeObjCGCAttr();
1166      LV.setNonGC(true);
1167    }
1168    setObjCGCLValueClass(getContext(), E, LV);
1169    return LV;
1170  }
1171
1172  // If we're emitting an instance method as an independent lvalue,
1173  // we're actually emitting a member pointer.
1174  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1175    if (MD->isInstance()) {
1176      llvm::Value *V = CGM.getCXXABI().EmitMemberPointer(MD);
1177      return MakeAddrLValue(V, MD->getType(), Alignment);
1178    }
1179  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1180    return EmitFunctionDeclLValue(*this, E, FD);
1181
1182  // If we're emitting a field as an independent lvalue, we're
1183  // actually emitting a member pointer.
1184  if (const FieldDecl *FD = dyn_cast<FieldDecl>(ND)) {
1185    llvm::Value *V = CGM.getCXXABI().EmitMemberPointer(FD);
1186    return MakeAddrLValue(V, FD->getType(), Alignment);
1187  }
1188
1189  assert(false && "Unhandled DeclRefExpr");
1190
1191  // an invalid LValue, but the assert will
1192  // ensure that this point is never reached.
1193  return LValue();
1194}
1195
1196LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1197  unsigned Alignment =
1198    CGF.getContext().getDeclAlign(E->getDecl()).getQuantity();
1199  return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
1200}
1201
1202LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1203  // __extension__ doesn't affect lvalue-ness.
1204  if (E->getOpcode() == UO_Extension)
1205    return EmitLValue(E->getSubExpr());
1206
1207  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1208  switch (E->getOpcode()) {
1209  default: assert(0 && "Unknown unary operator lvalue!");
1210  case UO_Deref: {
1211    QualType T = E->getSubExpr()->getType()->getPointeeType();
1212    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1213
1214    LValue LV = MakeAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1215    LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1216
1217    // We should not generate __weak write barrier on indirect reference
1218    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1219    // But, we continue to generate __strong write barrier on indirect write
1220    // into a pointer to object.
1221    if (getContext().getLangOptions().ObjC1 &&
1222        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1223        LV.isObjCWeak())
1224      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1225    return LV;
1226  }
1227  case UO_Real:
1228  case UO_Imag: {
1229    LValue LV = EmitLValue(E->getSubExpr());
1230    unsigned Idx = E->getOpcode() == UO_Imag;
1231    return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1232                                                    Idx, "idx"),
1233                          ExprTy);
1234  }
1235  case UO_PreInc:
1236  case UO_PreDec: {
1237    LValue LV = EmitLValue(E->getSubExpr());
1238    bool isInc = E->getOpcode() == UO_PreInc;
1239
1240    if (E->getType()->isAnyComplexType())
1241      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1242    else
1243      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1244    return LV;
1245  }
1246  }
1247}
1248
1249LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1250  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1251                        E->getType());
1252}
1253
1254LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1255  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1256                        E->getType());
1257}
1258
1259
1260LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1261  switch (E->getIdentType()) {
1262  default:
1263    return EmitUnsupportedLValue(E, "predefined expression");
1264
1265  case PredefinedExpr::Func:
1266  case PredefinedExpr::Function:
1267  case PredefinedExpr::PrettyFunction: {
1268    unsigned Type = E->getIdentType();
1269    std::string GlobalVarName;
1270
1271    switch (Type) {
1272    default: assert(0 && "Invalid type");
1273    case PredefinedExpr::Func:
1274      GlobalVarName = "__func__.";
1275      break;
1276    case PredefinedExpr::Function:
1277      GlobalVarName = "__FUNCTION__.";
1278      break;
1279    case PredefinedExpr::PrettyFunction:
1280      GlobalVarName = "__PRETTY_FUNCTION__.";
1281      break;
1282    }
1283
1284    llvm::StringRef FnName = CurFn->getName();
1285    if (FnName.startswith("\01"))
1286      FnName = FnName.substr(1);
1287    GlobalVarName += FnName;
1288
1289    const Decl *CurDecl = CurCodeDecl;
1290    if (CurDecl == 0)
1291      CurDecl = getContext().getTranslationUnitDecl();
1292
1293    std::string FunctionName =
1294      PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl);
1295
1296    llvm::Constant *C =
1297      CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1298    return MakeAddrLValue(C, E->getType());
1299  }
1300  }
1301}
1302
1303llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1304  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1305
1306  // If we are not optimzing, don't collapse all calls to trap in the function
1307  // to the same call, that way, in the debugger they can see which operation
1308  // did in fact fail.  If we are optimizing, we collapse all calls to trap down
1309  // to just one per function to save on codesize.
1310  if (GCO.OptimizationLevel && TrapBB)
1311    return TrapBB;
1312
1313  llvm::BasicBlock *Cont = 0;
1314  if (HaveInsertPoint()) {
1315    Cont = createBasicBlock("cont");
1316    EmitBranch(Cont);
1317  }
1318  TrapBB = createBasicBlock("trap");
1319  EmitBlock(TrapBB);
1320
1321  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1322  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1323  TrapCall->setDoesNotReturn();
1324  TrapCall->setDoesNotThrow();
1325  Builder.CreateUnreachable();
1326
1327  if (Cont)
1328    EmitBlock(Cont);
1329  return TrapBB;
1330}
1331
1332/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
1333/// array to pointer, return the array subexpression.
1334static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
1335  // If this isn't just an array->pointer decay, bail out.
1336  const CastExpr *CE = dyn_cast<CastExpr>(E);
1337  if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
1338    return 0;
1339
1340  // If this is a decay from variable width array, bail out.
1341  const Expr *SubExpr = CE->getSubExpr();
1342  if (SubExpr->getType()->isVariableArrayType())
1343    return 0;
1344
1345  return SubExpr;
1346}
1347
1348LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1349  // The index must always be an integer, which is not an aggregate.  Emit it.
1350  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1351  QualType IdxTy  = E->getIdx()->getType();
1352  bool IdxSigned = IdxTy->isSignedIntegerType();
1353
1354  // If the base is a vector type, then we are forming a vector element lvalue
1355  // with this subscript.
1356  if (E->getBase()->getType()->isVectorType()) {
1357    // Emit the vector as an lvalue to get its address.
1358    LValue LHS = EmitLValue(E->getBase());
1359    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1360    Idx = Builder.CreateIntCast(Idx, CGF.Int32Ty, IdxSigned, "vidx");
1361    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1362                                 E->getBase()->getType().getCVRQualifiers());
1363  }
1364
1365  // Extend or truncate the index type to 32 or 64-bits.
1366  if (!Idx->getType()->isIntegerTy(LLVMPointerWidth))
1367    Idx = Builder.CreateIntCast(Idx, IntPtrTy,
1368                                IdxSigned, "idxprom");
1369
1370  // FIXME: As llvm implements the object size checking, this can come out.
1371  if (CatchUndefined) {
1372    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())){
1373      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1374        if (ICE->getCastKind() == CK_ArrayToPointerDecay) {
1375          if (const ConstantArrayType *CAT
1376              = getContext().getAsConstantArrayType(DRE->getType())) {
1377            llvm::APInt Size = CAT->getSize();
1378            llvm::BasicBlock *Cont = createBasicBlock("cont");
1379            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1380                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1381                                 Cont, getTrapBB());
1382            EmitBlock(Cont);
1383          }
1384        }
1385      }
1386    }
1387  }
1388
1389  // We know that the pointer points to a type of the correct size, unless the
1390  // size is a VLA or Objective-C interface.
1391  llvm::Value *Address = 0;
1392  if (const VariableArrayType *VAT =
1393        getContext().getAsVariableArrayType(E->getType())) {
1394    llvm::Value *VLASize = GetVLASize(VAT);
1395
1396    Idx = Builder.CreateMul(Idx, VLASize);
1397
1398    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1399
1400    // The base must be a pointer, which is not an aggregate.  Emit it.
1401    llvm::Value *Base = EmitScalarExpr(E->getBase());
1402
1403    Address = Builder.CreateInBoundsGEP(Builder.CreateBitCast(Base, i8PTy),
1404                                        Idx, "arrayidx");
1405    Address = Builder.CreateBitCast(Address, Base->getType());
1406  } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
1407    // Indexing over an interface, as in "NSString *P; P[4];"
1408    llvm::Value *InterfaceSize =
1409      llvm::ConstantInt::get(Idx->getType(),
1410          getContext().getTypeSizeInChars(OIT).getQuantity());
1411
1412    Idx = Builder.CreateMul(Idx, InterfaceSize);
1413
1414    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1415
1416    // The base must be a pointer, which is not an aggregate.  Emit it.
1417    llvm::Value *Base = EmitScalarExpr(E->getBase());
1418    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1419                                Idx, "arrayidx");
1420    Address = Builder.CreateBitCast(Address, Base->getType());
1421  } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
1422    // If this is A[i] where A is an array, the frontend will have decayed the
1423    // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
1424    // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
1425    // "gep x, i" here.  Emit one "gep A, 0, i".
1426    assert(Array->getType()->isArrayType() &&
1427           "Array to pointer decay must have array source type!");
1428    llvm::Value *ArrayPtr = EmitLValue(Array).getAddress();
1429    llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
1430    llvm::Value *Args[] = { Zero, Idx };
1431
1432    Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, Args+2, "arrayidx");
1433  } else {
1434    // The base must be a pointer, which is not an aggregate.  Emit it.
1435    llvm::Value *Base = EmitScalarExpr(E->getBase());
1436    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1437  }
1438
1439  QualType T = E->getBase()->getType()->getPointeeType();
1440  assert(!T.isNull() &&
1441         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1442
1443  LValue LV = MakeAddrLValue(Address, T);
1444  LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
1445
1446  if (getContext().getLangOptions().ObjC1 &&
1447      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1448    LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1449    setObjCGCLValueClass(getContext(), E, LV);
1450  }
1451  return LV;
1452}
1453
1454static
1455llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1456                                       llvm::SmallVector<unsigned, 4> &Elts) {
1457  llvm::SmallVector<llvm::Constant*, 4> CElts;
1458
1459  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1460  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1461    CElts.push_back(llvm::ConstantInt::get(Int32Ty, Elts[i]));
1462
1463  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1464}
1465
1466LValue CodeGenFunction::
1467EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1468  // Emit the base vector as an l-value.
1469  LValue Base;
1470
1471  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1472  if (E->isArrow()) {
1473    // If it is a pointer to a vector, emit the address and form an lvalue with
1474    // it.
1475    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1476    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1477    Base = MakeAddrLValue(Ptr, PT->getPointeeType());
1478    Base.getQuals().removeObjCGCAttr();
1479  } else if (E->getBase()->isGLValue()) {
1480    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1481    // emit the base as an lvalue.
1482    assert(E->getBase()->getType()->isVectorType());
1483    Base = EmitLValue(E->getBase());
1484  } else {
1485    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1486    assert(E->getBase()->getType()->getAs<VectorType>() &&
1487           "Result must be a vector");
1488    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1489
1490    // Store the vector to memory (because LValue wants an address).
1491    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1492    Builder.CreateStore(Vec, VecMem);
1493    Base = MakeAddrLValue(VecMem, E->getBase()->getType());
1494  }
1495
1496  // Encode the element access list into a vector of unsigned indices.
1497  llvm::SmallVector<unsigned, 4> Indices;
1498  E->getEncodedElementAccess(Indices);
1499
1500  if (Base.isSimple()) {
1501    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1502    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1503                                    Base.getVRQualifiers());
1504  }
1505  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1506
1507  llvm::Constant *BaseElts = Base.getExtVectorElts();
1508  llvm::SmallVector<llvm::Constant *, 4> CElts;
1509
1510  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1511    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1512      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1513    else
1514      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1515  }
1516  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1517  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1518                                  Base.getVRQualifiers());
1519}
1520
1521LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1522  bool isNonGC = false;
1523  Expr *BaseExpr = E->getBase();
1524  llvm::Value *BaseValue = NULL;
1525  Qualifiers BaseQuals;
1526
1527  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1528  if (E->isArrow()) {
1529    BaseValue = EmitScalarExpr(BaseExpr);
1530    const PointerType *PTy =
1531      BaseExpr->getType()->getAs<PointerType>();
1532    BaseQuals = PTy->getPointeeType().getQualifiers();
1533  } else {
1534    LValue BaseLV = EmitLValue(BaseExpr);
1535    if (BaseLV.isNonGC())
1536      isNonGC = true;
1537    // FIXME: this isn't right for bitfields.
1538    BaseValue = BaseLV.getAddress();
1539    QualType BaseTy = BaseExpr->getType();
1540    BaseQuals = BaseTy.getQualifiers();
1541  }
1542
1543  NamedDecl *ND = E->getMemberDecl();
1544  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1545    LValue LV = EmitLValueForField(BaseValue, Field,
1546                                   BaseQuals.getCVRQualifiers());
1547    LV.setNonGC(isNonGC);
1548    setObjCGCLValueClass(getContext(), E, LV);
1549    return LV;
1550  }
1551
1552  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1553    return EmitGlobalVarDeclLValue(*this, E, VD);
1554
1555  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1556    return EmitFunctionDeclLValue(*this, E, FD);
1557
1558  assert(false && "Unhandled member declaration!");
1559  return LValue();
1560}
1561
1562LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
1563                                              const FieldDecl *Field,
1564                                              unsigned CVRQualifiers) {
1565  const CGRecordLayout &RL =
1566    CGM.getTypes().getCGRecordLayout(Field->getParent());
1567  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1568  return LValue::MakeBitfield(BaseValue, Info,
1569                             Field->getType().getCVRQualifiers()|CVRQualifiers);
1570}
1571
1572/// EmitLValueForAnonRecordField - Given that the field is a member of
1573/// an anonymous struct or union buried inside a record, and given
1574/// that the base value is a pointer to the enclosing record, derive
1575/// an lvalue for the ultimate field.
1576LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
1577                                                     const FieldDecl *Field,
1578                                                     unsigned CVRQualifiers) {
1579  llvm::SmallVector<const FieldDecl *, 8> Path;
1580  Path.push_back(Field);
1581
1582  while (Field->getParent()->isAnonymousStructOrUnion()) {
1583    const ValueDecl *VD = Field->getParent()->getAnonymousStructOrUnionObject();
1584    if (!isa<FieldDecl>(VD)) break;
1585    Field = cast<FieldDecl>(VD);
1586    Path.push_back(Field);
1587  }
1588
1589  llvm::SmallVectorImpl<const FieldDecl*>::reverse_iterator
1590    I = Path.rbegin(), E = Path.rend();
1591  while (true) {
1592    LValue LV = EmitLValueForField(BaseValue, *I, CVRQualifiers);
1593    if (++I == E) return LV;
1594
1595    assert(LV.isSimple());
1596    BaseValue = LV.getAddress();
1597    CVRQualifiers |= LV.getVRQualifiers();
1598  }
1599}
1600
1601LValue CodeGenFunction::EmitLValueForField(llvm::Value *BaseValue,
1602                                           const FieldDecl *Field,
1603                                           unsigned CVRQualifiers) {
1604  if (Field->isBitField())
1605    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1606
1607  const CGRecordLayout &RL =
1608    CGM.getTypes().getCGRecordLayout(Field->getParent());
1609  unsigned idx = RL.getLLVMFieldNo(Field);
1610  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1611
1612  // Match union field type.
1613  if (Field->getParent()->isUnion()) {
1614    const llvm::Type *FieldTy =
1615      CGM.getTypes().ConvertTypeForMem(Field->getType());
1616    const llvm::PointerType *BaseTy =
1617      cast<llvm::PointerType>(BaseValue->getType());
1618    unsigned AS = BaseTy->getAddressSpace();
1619    V = Builder.CreateBitCast(V,
1620                              llvm::PointerType::get(FieldTy, AS),
1621                              "tmp");
1622  }
1623  if (Field->getType()->isReferenceType())
1624    V = Builder.CreateLoad(V, "tmp");
1625
1626  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1627  LValue LV = MakeAddrLValue(V, Field->getType(), Alignment);
1628  LV.getQuals().addCVRQualifiers(CVRQualifiers);
1629
1630  // __weak attribute on a field is ignored.
1631  if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
1632    LV.getQuals().removeObjCGCAttr();
1633
1634  return LV;
1635}
1636
1637LValue
1638CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value *BaseValue,
1639                                                  const FieldDecl *Field,
1640                                                  unsigned CVRQualifiers) {
1641  QualType FieldType = Field->getType();
1642
1643  if (!FieldType->isReferenceType())
1644    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1645
1646  const CGRecordLayout &RL =
1647    CGM.getTypes().getCGRecordLayout(Field->getParent());
1648  unsigned idx = RL.getLLVMFieldNo(Field);
1649  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1650
1651  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1652
1653  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1654  return MakeAddrLValue(V, FieldType, Alignment);
1655}
1656
1657LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
1658  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1659  const Expr *InitExpr = E->getInitializer();
1660  LValue Result = MakeAddrLValue(DeclPtr, E->getType());
1661
1662  EmitAnyExprToMem(InitExpr, DeclPtr, /*Volatile*/ false, /*Init*/ true);
1663
1664  return Result;
1665}
1666
1667LValue
1668CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator *E) {
1669  if (E->isGLValue()) {
1670    if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1671      Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1672      if (Live)
1673        return EmitLValue(Live);
1674    }
1675
1676    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1677    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1678    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1679
1680    if (E->getLHS())
1681      EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1682    else {
1683      Expr *save = E->getSAVE();
1684      assert(save && "VisitConditionalOperator - save is null");
1685      // Intentianlly not doing direct assignment to ConditionalSaveExprs[save]
1686      LValue SaveVal = EmitLValue(save);
1687      ConditionalSaveLValueExprs[save] = SaveVal;
1688      EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1689    }
1690
1691    // Any temporaries created here are conditional.
1692    BeginConditionalBranch();
1693    EmitBlock(LHSBlock);
1694    LValue LHS = EmitLValue(E->getTrueExpr());
1695
1696    EndConditionalBranch();
1697
1698    if (!LHS.isSimple())
1699      return EmitUnsupportedLValue(E, "conditional operator");
1700
1701    // FIXME: We shouldn't need an alloca for this.
1702    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1703    Builder.CreateStore(LHS.getAddress(), Temp);
1704    EmitBranch(ContBlock);
1705
1706    // Any temporaries created here are conditional.
1707    BeginConditionalBranch();
1708    EmitBlock(RHSBlock);
1709    LValue RHS = EmitLValue(E->getRHS());
1710    EndConditionalBranch();
1711    if (!RHS.isSimple())
1712      return EmitUnsupportedLValue(E, "conditional operator");
1713
1714    Builder.CreateStore(RHS.getAddress(), Temp);
1715    EmitBranch(ContBlock);
1716
1717    EmitBlock(ContBlock);
1718
1719    Temp = Builder.CreateLoad(Temp, "lv");
1720    return MakeAddrLValue(Temp, E->getType());
1721  }
1722
1723  // ?: here should be an aggregate.
1724  assert((hasAggregateLLVMType(E->getType()) &&
1725          !E->getType()->isAnyComplexType()) &&
1726         "Unexpected conditional operator!");
1727
1728  return EmitAggExprToLValue(E);
1729}
1730
1731/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1732/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1733/// otherwise if a cast is needed by the code generator in an lvalue context,
1734/// then it must mean that we need the address of an aggregate in order to
1735/// access one of its fields.  This can happen for all the reasons that casts
1736/// are permitted with aggregate result, including noop aggregate casts, and
1737/// cast from scalar to union.
1738LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1739  switch (E->getCastKind()) {
1740  case CK_ToVoid:
1741    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1742
1743  case CK_Dependent:
1744    llvm_unreachable("dependent cast kind in IR gen!");
1745
1746  case CK_GetObjCProperty: {
1747    LValue LV = EmitLValue(E->getSubExpr());
1748    assert(LV.isPropertyRef());
1749    RValue RV = EmitLoadOfPropertyRefLValue(LV);
1750
1751    // Property is an aggregate r-value.
1752    if (RV.isAggregate()) {
1753      return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
1754    }
1755
1756    // Implicit property returns an l-value.
1757    assert(RV.isScalar());
1758    return MakeAddrLValue(RV.getScalarVal(), E->getSubExpr()->getType());
1759  }
1760
1761  case CK_NoOp:
1762    if (!E->getSubExpr()->isRValue() || E->getType()->isRecordType())
1763      return EmitLValue(E->getSubExpr());
1764    // Fall through to synthesize a temporary.
1765
1766  case CK_LValueToRValue:
1767  case CK_BitCast:
1768  case CK_ArrayToPointerDecay:
1769  case CK_FunctionToPointerDecay:
1770  case CK_NullToMemberPointer:
1771  case CK_NullToPointer:
1772  case CK_IntegralToPointer:
1773  case CK_PointerToIntegral:
1774  case CK_PointerToBoolean:
1775  case CK_VectorSplat:
1776  case CK_IntegralCast:
1777  case CK_IntegralToBoolean:
1778  case CK_IntegralToFloating:
1779  case CK_FloatingToIntegral:
1780  case CK_FloatingToBoolean:
1781  case CK_FloatingCast:
1782  case CK_FloatingRealToComplex:
1783  case CK_FloatingComplexToReal:
1784  case CK_FloatingComplexToBoolean:
1785  case CK_FloatingComplexCast:
1786  case CK_FloatingComplexToIntegralComplex:
1787  case CK_IntegralRealToComplex:
1788  case CK_IntegralComplexToReal:
1789  case CK_IntegralComplexToBoolean:
1790  case CK_IntegralComplexCast:
1791  case CK_IntegralComplexToFloatingComplex:
1792  case CK_DerivedToBaseMemberPointer:
1793  case CK_BaseToDerivedMemberPointer:
1794  case CK_MemberPointerToBoolean:
1795  case CK_AnyPointerToBlockPointerCast: {
1796    // These casts only produce lvalues when we're binding a reference to a
1797    // temporary realized from a (converted) pure rvalue. Emit the expression
1798    // as a value, copy it into a temporary, and return an lvalue referring to
1799    // that temporary.
1800    llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
1801    EmitAnyExprToMem(E, V, false, false);
1802    return MakeAddrLValue(V, E->getType());
1803  }
1804
1805  case CK_Dynamic: {
1806    LValue LV = EmitLValue(E->getSubExpr());
1807    llvm::Value *V = LV.getAddress();
1808    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1809    return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
1810  }
1811
1812  case CK_ConstructorConversion:
1813  case CK_UserDefinedConversion:
1814  case CK_AnyPointerToObjCPointerCast:
1815    return EmitLValue(E->getSubExpr());
1816
1817  case CK_UncheckedDerivedToBase:
1818  case CK_DerivedToBase: {
1819    const RecordType *DerivedClassTy =
1820      E->getSubExpr()->getType()->getAs<RecordType>();
1821    CXXRecordDecl *DerivedClassDecl =
1822      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1823
1824    LValue LV = EmitLValue(E->getSubExpr());
1825    llvm::Value *This = LV.getAddress();
1826
1827    // Perform the derived-to-base conversion
1828    llvm::Value *Base =
1829      GetAddressOfBaseClass(This, DerivedClassDecl,
1830                            E->path_begin(), E->path_end(),
1831                            /*NullCheckValue=*/false);
1832
1833    return MakeAddrLValue(Base, E->getType());
1834  }
1835  case CK_ToUnion:
1836    return EmitAggExprToLValue(E);
1837  case CK_BaseToDerived: {
1838    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1839    CXXRecordDecl *DerivedClassDecl =
1840      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1841
1842    LValue LV = EmitLValue(E->getSubExpr());
1843
1844    // Perform the base-to-derived conversion
1845    llvm::Value *Derived =
1846      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
1847                               E->path_begin(), E->path_end(),
1848                               /*NullCheckValue=*/false);
1849
1850    return MakeAddrLValue(Derived, E->getType());
1851  }
1852  case CK_LValueBitCast: {
1853    // This must be a reinterpret_cast (or c-style equivalent).
1854    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1855
1856    LValue LV = EmitLValue(E->getSubExpr());
1857    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1858                                           ConvertType(CE->getTypeAsWritten()));
1859    return MakeAddrLValue(V, E->getType());
1860  }
1861  case CK_ObjCObjectLValueCast: {
1862    LValue LV = EmitLValue(E->getSubExpr());
1863    QualType ToType = getContext().getLValueReferenceType(E->getType());
1864    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1865                                           ConvertType(ToType));
1866    return MakeAddrLValue(V, E->getType());
1867  }
1868  }
1869
1870  llvm_unreachable("Unhandled lvalue cast kind?");
1871}
1872
1873LValue CodeGenFunction::EmitNullInitializationLValue(
1874                                              const CXXScalarValueInitExpr *E) {
1875  QualType Ty = E->getType();
1876  LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
1877  EmitNullInitialization(LV.getAddress(), Ty);
1878  return LV;
1879}
1880
1881//===--------------------------------------------------------------------===//
1882//                             Expression Emission
1883//===--------------------------------------------------------------------===//
1884
1885
1886RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1887                                     ReturnValueSlot ReturnValue) {
1888  // Builtins never have block type.
1889  if (E->getCallee()->getType()->isBlockPointerType())
1890    return EmitBlockCallExpr(E, ReturnValue);
1891
1892  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1893    return EmitCXXMemberCallExpr(CE, ReturnValue);
1894
1895  const Decl *TargetDecl = 0;
1896  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1897    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1898      TargetDecl = DRE->getDecl();
1899      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1900        if (unsigned builtinID = FD->getBuiltinID())
1901          return EmitBuiltinExpr(FD, builtinID, E);
1902    }
1903  }
1904
1905  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1906    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1907      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1908
1909  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1910    // C++ [expr.pseudo]p1:
1911    //   The result shall only be used as the operand for the function call
1912    //   operator (), and the result of such a call has type void. The only
1913    //   effect is the evaluation of the postfix-expression before the dot or
1914    //   arrow.
1915    EmitScalarExpr(E->getCallee());
1916    return RValue::get(0);
1917  }
1918
1919  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1920  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1921                  E->arg_begin(), E->arg_end(), TargetDecl);
1922}
1923
1924LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1925  // Comma expressions just emit their LHS then their RHS as an l-value.
1926  if (E->getOpcode() == BO_Comma) {
1927    EmitAnyExpr(E->getLHS());
1928    EnsureInsertPoint();
1929    return EmitLValue(E->getRHS());
1930  }
1931
1932  if (E->getOpcode() == BO_PtrMemD ||
1933      E->getOpcode() == BO_PtrMemI)
1934    return EmitPointerToDataMemberBinaryExpr(E);
1935
1936  assert(E->isAssignmentOp() && "unexpected binary l-value");
1937
1938  if (!hasAggregateLLVMType(E->getType())) {
1939    if (E->isCompoundAssignmentOp())
1940      return EmitCompoundAssignOperatorLValue(cast<CompoundAssignOperator>(E));
1941
1942    assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
1943
1944    // Emit the LHS as an l-value.
1945    LValue LV = EmitLValue(E->getLHS());
1946    // Store the value through the l-value.
1947    EmitStoreThroughLValue(EmitAnyExpr(E->getRHS()), LV, E->getType());
1948    return LV;
1949  }
1950
1951  if (E->getType()->isAnyComplexType())
1952    return EmitComplexAssignmentLValue(E);
1953
1954  // The compound assignment operators are not used for aggregates.
1955  assert(E->getOpcode() == BO_Assign && "aggregate compound assignment?");
1956
1957  return EmitAggExprToLValue(E);
1958}
1959
1960LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1961  RValue RV = EmitCallExpr(E);
1962
1963  if (!RV.isScalar())
1964    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
1965
1966  assert(E->getCallReturnType()->isReferenceType() &&
1967         "Can't have a scalar return unless the return type is a "
1968         "reference type!");
1969
1970  return MakeAddrLValue(RV.getScalarVal(), E->getType());
1971}
1972
1973LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1974  // FIXME: This shouldn't require another copy.
1975  return EmitAggExprToLValue(E);
1976}
1977
1978LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1979  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
1980         && "binding l-value to type which needs a temporary");
1981  AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
1982  EmitCXXConstructExpr(E, Slot);
1983  return MakeAddrLValue(Slot.getAddr(), E->getType());
1984}
1985
1986LValue
1987CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1988  return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
1989}
1990
1991LValue
1992CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1993  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
1994  Slot.setLifetimeExternallyManaged();
1995  EmitAggExpr(E->getSubExpr(), Slot);
1996  EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
1997  return MakeAddrLValue(Slot.getAddr(), E->getType());
1998}
1999
2000LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
2001  RValue RV = EmitObjCMessageExpr(E);
2002
2003  if (!RV.isScalar())
2004    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2005
2006  assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
2007         "Can't have a scalar return unless the return type is a "
2008         "reference type!");
2009
2010  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2011}
2012
2013LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
2014  llvm::Value *V =
2015    CGM.getObjCRuntime().GetSelector(Builder, E->getSelector(), true);
2016  return MakeAddrLValue(V, E->getType());
2017}
2018
2019llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
2020                                             const ObjCIvarDecl *Ivar) {
2021  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
2022}
2023
2024LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
2025                                          llvm::Value *BaseValue,
2026                                          const ObjCIvarDecl *Ivar,
2027                                          unsigned CVRQualifiers) {
2028  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
2029                                                   Ivar, CVRQualifiers);
2030}
2031
2032LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
2033  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
2034  llvm::Value *BaseValue = 0;
2035  const Expr *BaseExpr = E->getBase();
2036  Qualifiers BaseQuals;
2037  QualType ObjectTy;
2038  if (E->isArrow()) {
2039    BaseValue = EmitScalarExpr(BaseExpr);
2040    ObjectTy = BaseExpr->getType()->getPointeeType();
2041    BaseQuals = ObjectTy.getQualifiers();
2042  } else {
2043    LValue BaseLV = EmitLValue(BaseExpr);
2044    // FIXME: this isn't right for bitfields.
2045    BaseValue = BaseLV.getAddress();
2046    ObjectTy = BaseExpr->getType();
2047    BaseQuals = ObjectTy.getQualifiers();
2048  }
2049
2050  LValue LV =
2051    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
2052                      BaseQuals.getCVRQualifiers());
2053  setObjCGCLValueClass(getContext(), E, LV);
2054  return LV;
2055}
2056
2057LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
2058  // Can only get l-value for message expression returning aggregate type
2059  RValue RV = EmitAnyExprToTemp(E);
2060  return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2061}
2062
2063RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
2064                                 ReturnValueSlot ReturnValue,
2065                                 CallExpr::const_arg_iterator ArgBeg,
2066                                 CallExpr::const_arg_iterator ArgEnd,
2067                                 const Decl *TargetDecl) {
2068  // Get the actual function type. The callee type will always be a pointer to
2069  // function type or a block pointer type.
2070  assert(CalleeType->isFunctionPointerType() &&
2071         "Call must have function pointer type!");
2072
2073  CalleeType = getContext().getCanonicalType(CalleeType);
2074
2075  const FunctionType *FnType
2076    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
2077  QualType ResultType = FnType->getResultType();
2078
2079  CallArgList Args;
2080  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
2081
2082  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
2083                  Callee, ReturnValue, Args, TargetDecl);
2084}
2085
2086LValue CodeGenFunction::
2087EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
2088  llvm::Value *BaseV;
2089  if (E->getOpcode() == BO_PtrMemI)
2090    BaseV = EmitScalarExpr(E->getLHS());
2091  else
2092    BaseV = EmitLValue(E->getLHS()).getAddress();
2093
2094  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
2095
2096  const MemberPointerType *MPT
2097    = E->getRHS()->getType()->getAs<MemberPointerType>();
2098
2099  llvm::Value *AddV =
2100    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
2101
2102  return MakeAddrLValue(AddV, MPT->getPointeeType());
2103}
2104
2105