CGExpr.cpp revision 6ec687d2ad8b4968675f7baec15ba302b4d7e199 
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 "CGObjCRuntime.h"
18#include "clang/AST/ASTContext.h"
19#include "clang/AST/DeclObjC.h"
20#include "llvm/Target/TargetData.h"
21using namespace clang;
22using namespace CodeGen;
23
24//===--------------------------------------------------------------------===//
25//                        Miscellaneous Helper Methods
26//===--------------------------------------------------------------------===//
27
28/// CreateTempAlloca - This creates a alloca and inserts it into the entry
29/// block.
30llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
31                                                    const llvm::Twine &Name) {
32  if (!Builder.isNamePreserving())
33    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
34  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
35}
36
37/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
38/// expression and compare the result against zero, returning an Int1Ty value.
39llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
40  QualType BoolTy = getContext().BoolTy;
41  if (!E->getType()->isAnyComplexType())
42    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
43
44  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
45}
46
47/// EmitAnyExpr - Emit code to compute the specified expression which can have
48/// any type.  The result is returned as an RValue struct.  If this is an
49/// aggregate expression, the aggloc/agglocvolatile arguments indicate where the
50/// result should be returned.
51RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
52                                    bool IsAggLocVolatile, bool IgnoreResult,
53                                    bool IsInitializer) {
54  if (!hasAggregateLLVMType(E->getType()))
55    return RValue::get(EmitScalarExpr(E, IgnoreResult));
56  else if (E->getType()->isAnyComplexType())
57    return RValue::getComplex(EmitComplexExpr(E, false, false,
58                                              IgnoreResult, IgnoreResult));
59
60  EmitAggExpr(E, AggLoc, IsAggLocVolatile, IgnoreResult, IsInitializer);
61  return RValue::getAggregate(AggLoc, IsAggLocVolatile);
62}
63
64/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
65/// always be accessible even if no aggregate location is provided.
66RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E,
67                                          bool IsAggLocVolatile,
68                                          bool IsInitializer) {
69  llvm::Value *AggLoc = 0;
70
71  if (hasAggregateLLVMType(E->getType()) &&
72      !E->getType()->isAnyComplexType())
73    AggLoc = CreateTempAlloca(ConvertType(E->getType()), "agg.tmp");
74  return EmitAnyExpr(E, AggLoc, IsAggLocVolatile, /*IgnoreResult=*/false,
75                     IsInitializer);
76}
77
78RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr* E,
79                                                   QualType DestType,
80                                                   bool IsInitializer) {
81  bool ShouldDestroyTemporaries = false;
82  unsigned OldNumLiveTemporaries = 0;
83
84  if (const CXXExprWithTemporaries *TE = dyn_cast<CXXExprWithTemporaries>(E)) {
85    ShouldDestroyTemporaries = TE->shouldDestroyTemporaries();
86
87    // Keep track of the current cleanup stack depth.
88    if (ShouldDestroyTemporaries)
89      OldNumLiveTemporaries = LiveTemporaries.size();
90
91    E = TE->getSubExpr();
92  }
93
94  RValue Val;
95  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
96    // Emit the expr as an lvalue.
97    LValue LV = EmitLValue(E);
98    if (LV.isSimple())
99      return RValue::get(LV.getAddress());
100    Val = EmitLoadOfLValue(LV, E->getType());
101
102    if (ShouldDestroyTemporaries) {
103      // Pop temporaries.
104      while (LiveTemporaries.size() > OldNumLiveTemporaries)
105        PopCXXTemporary();
106    }
107  } else {
108    const CXXRecordDecl *BaseClassDecl = 0;
109    const CXXRecordDecl *DerivedClassDecl = 0;
110
111    if (const CastExpr *CE =
112          dyn_cast<CastExpr>(E->IgnoreParenNoopCasts(getContext()))) {
113      if (CE->getCastKind() == CastExpr::CK_DerivedToBase) {
114        E = CE->getSubExpr();
115
116        BaseClassDecl =
117          cast<CXXRecordDecl>(CE->getType()->getAs<RecordType>()->getDecl());
118        DerivedClassDecl =
119          cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
120      }
121    }
122
123    Val = EmitAnyExprToTemp(E, /*IsAggLocVolatile=*/false,
124                            IsInitializer);
125
126    if (ShouldDestroyTemporaries) {
127      // Pop temporaries.
128      while (LiveTemporaries.size() > OldNumLiveTemporaries)
129        PopCXXTemporary();
130    }
131
132    if (IsInitializer) {
133      // We might have to destroy the temporary variable.
134      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
135        if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
136          if (!ClassDecl->hasTrivialDestructor()) {
137            const CXXDestructorDecl *Dtor =
138              ClassDecl->getDestructor(getContext());
139
140            {
141              DelayedCleanupBlock Scope(*this);
142              EmitCXXDestructorCall(Dtor, Dtor_Complete,
143                                    Val.getAggregateAddr());
144
145              // Make sure to jump to the exit block.
146              EmitBranch(Scope.getCleanupExitBlock());
147            }
148            if (Exceptions) {
149              EHCleanupBlock Cleanup(*this);
150              EmitCXXDestructorCall(Dtor, Dtor_Complete,
151                                    Val.getAggregateAddr());
152            }
153          }
154        }
155      }
156    }
157
158    // Check if need to perform the derived-to-base cast.
159    if (BaseClassDecl) {
160      llvm::Value *Derived = Val.getAggregateAddr();
161      llvm::Value *Base =
162        GetAddressOfBaseClass(Derived, DerivedClassDecl, BaseClassDecl,
163                              /*NullCheckValue=*/false);
164      return RValue::get(Base);
165    }
166  }
167
168  if (Val.isAggregate()) {
169    Val = RValue::get(Val.getAggregateAddr());
170  } else {
171    // Create a temporary variable that we can bind the reference to.
172    llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()),
173                                         "reftmp");
174    if (Val.isScalar())
175      EmitStoreOfScalar(Val.getScalarVal(), Temp, false, E->getType());
176    else
177      StoreComplexToAddr(Val.getComplexVal(), Temp, false);
178    Val = RValue::get(Temp);
179  }
180
181  return Val;
182}
183
184
185/// getAccessedFieldNo - Given an encoded value and a result number, return the
186/// input field number being accessed.
187unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
188                                             const llvm::Constant *Elts) {
189  if (isa<llvm::ConstantAggregateZero>(Elts))
190    return 0;
191
192  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
193}
194
195
196//===----------------------------------------------------------------------===//
197//                         LValue Expression Emission
198//===----------------------------------------------------------------------===//
199
200RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
201  if (Ty->isVoidType())
202    return RValue::get(0);
203
204  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
205    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
206    llvm::Value *U = llvm::UndefValue::get(EltTy);
207    return RValue::getComplex(std::make_pair(U, U));
208  }
209
210  if (hasAggregateLLVMType(Ty)) {
211    const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
212    return RValue::getAggregate(llvm::UndefValue::get(LTy));
213  }
214
215  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
216}
217
218RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
219                                              const char *Name) {
220  ErrorUnsupported(E, Name);
221  return GetUndefRValue(E->getType());
222}
223
224LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
225                                              const char *Name) {
226  ErrorUnsupported(E, Name);
227  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
228  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
229                          MakeQualifiers(E->getType()));
230}
231
232/// EmitLValue - Emit code to compute a designator that specifies the location
233/// of the expression.
234///
235/// This can return one of two things: a simple address or a bitfield reference.
236/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
237/// an LLVM pointer type.
238///
239/// If this returns a bitfield reference, nothing about the pointee type of the
240/// LLVM value is known: For example, it may not be a pointer to an integer.
241///
242/// If this returns a normal address, and if the lvalue's C type is fixed size,
243/// this method guarantees that the returned pointer type will point to an LLVM
244/// type of the same size of the lvalue's type.  If the lvalue has a variable
245/// length type, this is not possible.
246///
247LValue CodeGenFunction::EmitLValue(const Expr *E) {
248  switch (E->getStmtClass()) {
249  default: return EmitUnsupportedLValue(E, "l-value expression");
250
251  case Expr::ObjCIsaExprClass:
252    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
253  case Expr::BinaryOperatorClass:
254    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
255  case Expr::CallExprClass:
256  case Expr::CXXMemberCallExprClass:
257  case Expr::CXXOperatorCallExprClass:
258    return EmitCallExprLValue(cast<CallExpr>(E));
259  case Expr::VAArgExprClass:
260    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
261  case Expr::DeclRefExprClass:
262    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
263  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
264  case Expr::PredefinedExprClass:
265    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
266  case Expr::StringLiteralClass:
267    return EmitStringLiteralLValue(cast<StringLiteral>(E));
268  case Expr::ObjCEncodeExprClass:
269    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
270
271  case Expr::BlockDeclRefExprClass:
272    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
273
274  case Expr::CXXTemporaryObjectExprClass:
275  case Expr::CXXConstructExprClass:
276    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
277  case Expr::CXXBindTemporaryExprClass:
278    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
279  case Expr::CXXExprWithTemporariesClass:
280    return EmitCXXExprWithTemporariesLValue(cast<CXXExprWithTemporaries>(E));
281  case Expr::CXXZeroInitValueExprClass:
282    return EmitNullInitializationLValue(cast<CXXZeroInitValueExpr>(E));
283  case Expr::CXXDefaultArgExprClass:
284    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
285  case Expr::CXXTypeidExprClass:
286    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
287
288  case Expr::ObjCMessageExprClass:
289    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
290  case Expr::ObjCIvarRefExprClass:
291    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
292  case Expr::ObjCPropertyRefExprClass:
293    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
294  case Expr::ObjCImplicitSetterGetterRefExprClass:
295    return EmitObjCKVCRefLValue(cast<ObjCImplicitSetterGetterRefExpr>(E));
296  case Expr::ObjCSuperExprClass:
297    return EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
298
299  case Expr::StmtExprClass:
300    return EmitStmtExprLValue(cast<StmtExpr>(E));
301  case Expr::UnaryOperatorClass:
302    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
303  case Expr::ArraySubscriptExprClass:
304    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
305  case Expr::ExtVectorElementExprClass:
306    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
307  case Expr::MemberExprClass:
308    return EmitMemberExpr(cast<MemberExpr>(E));
309  case Expr::CompoundLiteralExprClass:
310    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
311  case Expr::ConditionalOperatorClass:
312    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
313  case Expr::ChooseExprClass:
314    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
315  case Expr::ImplicitCastExprClass:
316  case Expr::CStyleCastExprClass:
317  case Expr::CXXFunctionalCastExprClass:
318  case Expr::CXXStaticCastExprClass:
319  case Expr::CXXDynamicCastExprClass:
320  case Expr::CXXReinterpretCastExprClass:
321  case Expr::CXXConstCastExprClass:
322    return EmitCastLValue(cast<CastExpr>(E));
323  }
324}
325
326llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
327                                               QualType Ty) {
328  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
329  if (Volatile)
330    Load->setVolatile(true);
331
332  // Bool can have different representation in memory than in registers.
333  llvm::Value *V = Load;
334  if (Ty->isBooleanType())
335    if (V->getType() != llvm::Type::getInt1Ty(VMContext))
336      V = Builder.CreateTrunc(V, llvm::Type::getInt1Ty(VMContext), "tobool");
337
338  return V;
339}
340
341void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
342                                        bool Volatile, QualType Ty) {
343
344  if (Ty->isBooleanType()) {
345    // Bool can have different representation in memory than in registers.
346    const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
347    Value = Builder.CreateIntCast(Value, DstPtr->getElementType(), false);
348  }
349  Builder.CreateStore(Value, Addr, Volatile);
350}
351
352/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
353/// method emits the address of the lvalue, then loads the result as an rvalue,
354/// returning the rvalue.
355RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
356  if (LV.isObjCWeak()) {
357    // load of a __weak object.
358    llvm::Value *AddrWeakObj = LV.getAddress();
359    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
360                                                             AddrWeakObj));
361  }
362
363  if (LV.isSimple()) {
364    llvm::Value *Ptr = LV.getAddress();
365    const llvm::Type *EltTy =
366      cast<llvm::PointerType>(Ptr->getType())->getElementType();
367
368    // Simple scalar l-value.
369    if (EltTy->isSingleValueType())
370      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
371                                          ExprType));
372
373    assert(ExprType->isFunctionType() && "Unknown scalar value");
374    return RValue::get(Ptr);
375  }
376
377  if (LV.isVectorElt()) {
378    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
379                                          LV.isVolatileQualified(), "tmp");
380    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
381                                                    "vecext"));
382  }
383
384  // If this is a reference to a subset of the elements of a vector, either
385  // shuffle the input or extract/insert them as appropriate.
386  if (LV.isExtVectorElt())
387    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
388
389  if (LV.isBitfield())
390    return EmitLoadOfBitfieldLValue(LV, ExprType);
391
392  if (LV.isPropertyRef())
393    return EmitLoadOfPropertyRefLValue(LV, ExprType);
394
395  assert(LV.isKVCRef() && "Unknown LValue type!");
396  return EmitLoadOfKVCRefLValue(LV, ExprType);
397}
398
399RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
400                                                 QualType ExprType) {
401  unsigned StartBit = LV.getBitfieldStartBit();
402  unsigned BitfieldSize = LV.getBitfieldSize();
403  llvm::Value *Ptr = LV.getBitfieldAddr();
404
405  const llvm::Type *EltTy =
406    cast<llvm::PointerType>(Ptr->getType())->getElementType();
407  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
408
409  // In some cases the bitfield may straddle two memory locations.  Currently we
410  // load the entire bitfield, then do the magic to sign-extend it if
411  // necessary. This results in somewhat more code than necessary for the common
412  // case (one load), since two shifts accomplish both the masking and sign
413  // extension.
414  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
415  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
416
417  // Shift to proper location.
418  if (StartBit)
419    Val = Builder.CreateLShr(Val, StartBit, "bf.lo");
420
421  // Mask off unused bits.
422  llvm::Constant *LowMask = llvm::ConstantInt::get(VMContext,
423                                llvm::APInt::getLowBitsSet(EltTySize, LowBits));
424  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
425
426  // Fetch the high bits if necessary.
427  if (LowBits < BitfieldSize) {
428    unsigned HighBits = BitfieldSize - LowBits;
429    llvm::Value *HighPtr = Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
430                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
431    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
432                                              LV.isVolatileQualified(),
433                                              "tmp");
434
435    // Mask off unused bits.
436    llvm::Constant *HighMask = llvm::ConstantInt::get(VMContext,
437                               llvm::APInt::getLowBitsSet(EltTySize, HighBits));
438    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
439
440    // Shift to proper location and or in to bitfield value.
441    HighVal = Builder.CreateShl(HighVal, LowBits);
442    Val = Builder.CreateOr(Val, HighVal, "bf.val");
443  }
444
445  // Sign extend if necessary.
446  if (LV.isBitfieldSigned()) {
447    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
448                                                    EltTySize - BitfieldSize);
449    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
450                             ExtraBits, "bf.val.sext");
451  }
452
453  // The bitfield type and the normal type differ when the storage sizes differ
454  // (currently just _Bool).
455  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
456
457  return RValue::get(Val);
458}
459
460RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
461                                                    QualType ExprType) {
462  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
463}
464
465RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
466                                               QualType ExprType) {
467  return EmitObjCPropertyGet(LV.getKVCRefExpr());
468}
469
470// If this is a reference to a subset of the elements of a vector, create an
471// appropriate shufflevector.
472RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
473                                                         QualType ExprType) {
474  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
475                                        LV.isVolatileQualified(), "tmp");
476
477  const llvm::Constant *Elts = LV.getExtVectorElts();
478
479  // If the result of the expression is a non-vector type, we must be extracting
480  // a single element.  Just codegen as an extractelement.
481  const VectorType *ExprVT = ExprType->getAs<VectorType>();
482  if (!ExprVT) {
483    unsigned InIdx = getAccessedFieldNo(0, Elts);
484    llvm::Value *Elt = llvm::ConstantInt::get(
485                                      llvm::Type::getInt32Ty(VMContext), InIdx);
486    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
487  }
488
489  // Always use shuffle vector to try to retain the original program structure
490  unsigned NumResultElts = ExprVT->getNumElements();
491
492  llvm::SmallVector<llvm::Constant*, 4> Mask;
493  for (unsigned i = 0; i != NumResultElts; ++i) {
494    unsigned InIdx = getAccessedFieldNo(i, Elts);
495    Mask.push_back(llvm::ConstantInt::get(
496                                     llvm::Type::getInt32Ty(VMContext), InIdx));
497  }
498
499  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
500  Vec = Builder.CreateShuffleVector(Vec,
501                                    llvm::UndefValue::get(Vec->getType()),
502                                    MaskV, "tmp");
503  return RValue::get(Vec);
504}
505
506
507
508/// EmitStoreThroughLValue - Store the specified rvalue into the specified
509/// lvalue, where both are guaranteed to the have the same type, and that type
510/// is 'Ty'.
511void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
512                                             QualType Ty) {
513  if (!Dst.isSimple()) {
514    if (Dst.isVectorElt()) {
515      // Read/modify/write the vector, inserting the new element.
516      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
517                                            Dst.isVolatileQualified(), "tmp");
518      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
519                                        Dst.getVectorIdx(), "vecins");
520      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
521      return;
522    }
523
524    // If this is an update of extended vector elements, insert them as
525    // appropriate.
526    if (Dst.isExtVectorElt())
527      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
528
529    if (Dst.isBitfield())
530      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
531
532    if (Dst.isPropertyRef())
533      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
534
535    assert(Dst.isKVCRef() && "Unknown LValue type");
536    return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
537  }
538
539  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
540    // load of a __weak object.
541    llvm::Value *LvalueDst = Dst.getAddress();
542    llvm::Value *src = Src.getScalarVal();
543     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
544    return;
545  }
546
547  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
548    // load of a __strong object.
549    llvm::Value *LvalueDst = Dst.getAddress();
550    llvm::Value *src = Src.getScalarVal();
551    if (Dst.isObjCIvar()) {
552      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
553      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
554      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
555      llvm::Value *dst = RHS;
556      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
557      llvm::Value *LHS =
558        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
559      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
560      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
561                                              BytesBetween);
562    } else if (Dst.isGlobalObjCRef())
563      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
564    else
565      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
566    return;
567  }
568
569  assert(Src.isScalar() && "Can't emit an agg store with this method");
570  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
571                    Dst.isVolatileQualified(), Ty);
572}
573
574void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
575                                                     QualType Ty,
576                                                     llvm::Value **Result) {
577  unsigned StartBit = Dst.getBitfieldStartBit();
578  unsigned BitfieldSize = Dst.getBitfieldSize();
579  llvm::Value *Ptr = Dst.getBitfieldAddr();
580
581  const llvm::Type *EltTy =
582    cast<llvm::PointerType>(Ptr->getType())->getElementType();
583  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
584
585  // Get the new value, cast to the appropriate type and masked to exactly the
586  // size of the bit-field.
587  llvm::Value *SrcVal = Src.getScalarVal();
588  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
589  llvm::Constant *Mask = llvm::ConstantInt::get(VMContext,
590                           llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
591  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
592
593  // Return the new value of the bit-field, if requested.
594  if (Result) {
595    // Cast back to the proper type for result.
596    const llvm::Type *SrcTy = SrcVal->getType();
597    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
598                                                  "bf.reload.val");
599
600    // Sign extend if necessary.
601    if (Dst.isBitfieldSigned()) {
602      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
603      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
604                                                      SrcTySize - BitfieldSize);
605      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
606                                    ExtraBits, "bf.reload.sext");
607    }
608
609    *Result = SrcTrunc;
610  }
611
612  // In some cases the bitfield may straddle two memory locations.  Emit the low
613  // part first and check to see if the high needs to be done.
614  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
615  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
616                                           "bf.prev.low");
617
618  // Compute the mask for zero-ing the low part of this bitfield.
619  llvm::Constant *InvMask =
620    llvm::ConstantInt::get(VMContext,
621             ~llvm::APInt::getBitsSet(EltTySize, StartBit, StartBit + LowBits));
622
623  // Compute the new low part as
624  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
625  // with the shift of NewVal implicitly stripping the high bits.
626  llvm::Value *NewLowVal =
627    Builder.CreateShl(NewVal, StartBit, "bf.value.lo");
628  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
629  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
630
631  // Write back.
632  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
633
634  // If the low part doesn't cover the bitfield emit a high part.
635  if (LowBits < BitfieldSize) {
636    unsigned HighBits = BitfieldSize - LowBits;
637    llvm::Value *HighPtr =  Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
638                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
639    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
640                                              Dst.isVolatileQualified(),
641                                              "bf.prev.hi");
642
643    // Compute the mask for zero-ing the high part of this bitfield.
644    llvm::Constant *InvMask =
645      llvm::ConstantInt::get(VMContext, ~llvm::APInt::getLowBitsSet(EltTySize,
646                               HighBits));
647
648    // Compute the new high part as
649    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
650    // where the high bits of NewVal have already been cleared and the
651    // shift stripping the low bits.
652    llvm::Value *NewHighVal =
653      Builder.CreateLShr(NewVal, LowBits, "bf.value.high");
654    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
655    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
656
657    // Write back.
658    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
659  }
660}
661
662void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
663                                                        LValue Dst,
664                                                        QualType Ty) {
665  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
666}
667
668void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
669                                                   LValue Dst,
670                                                   QualType Ty) {
671  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
672}
673
674void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
675                                                               LValue Dst,
676                                                               QualType Ty) {
677  // This access turns into a read/modify/write of the vector.  Load the input
678  // value now.
679  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
680                                        Dst.isVolatileQualified(), "tmp");
681  const llvm::Constant *Elts = Dst.getExtVectorElts();
682
683  llvm::Value *SrcVal = Src.getScalarVal();
684
685  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
686    unsigned NumSrcElts = VTy->getNumElements();
687    unsigned NumDstElts =
688       cast<llvm::VectorType>(Vec->getType())->getNumElements();
689    if (NumDstElts == NumSrcElts) {
690      // Use shuffle vector is the src and destination are the same number of
691      // elements and restore the vector mask since it is on the side it will be
692      // stored.
693      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
694      for (unsigned i = 0; i != NumSrcElts; ++i) {
695        unsigned InIdx = getAccessedFieldNo(i, Elts);
696        Mask[InIdx] = llvm::ConstantInt::get(
697                                          llvm::Type::getInt32Ty(VMContext), i);
698      }
699
700      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
701      Vec = Builder.CreateShuffleVector(SrcVal,
702                                        llvm::UndefValue::get(Vec->getType()),
703                                        MaskV, "tmp");
704    } else if (NumDstElts > NumSrcElts) {
705      // Extended the source vector to the same length and then shuffle it
706      // into the destination.
707      // FIXME: since we're shuffling with undef, can we just use the indices
708      //        into that?  This could be simpler.
709      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
710      const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
711      unsigned i;
712      for (i = 0; i != NumSrcElts; ++i)
713        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
714      for (; i != NumDstElts; ++i)
715        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
716      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
717                                                        ExtMask.size());
718      llvm::Value *ExtSrcVal =
719        Builder.CreateShuffleVector(SrcVal,
720                                    llvm::UndefValue::get(SrcVal->getType()),
721                                    ExtMaskV, "tmp");
722      // build identity
723      llvm::SmallVector<llvm::Constant*, 4> Mask;
724      for (unsigned i = 0; i != NumDstElts; ++i)
725        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
726
727      // modify when what gets shuffled in
728      for (unsigned i = 0; i != NumSrcElts; ++i) {
729        unsigned Idx = getAccessedFieldNo(i, Elts);
730        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
731      }
732      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
733      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
734    } else {
735      // We should never shorten the vector
736      assert(0 && "unexpected shorten vector length");
737    }
738  } else {
739    // If the Src is a scalar (not a vector) it must be updating one element.
740    unsigned InIdx = getAccessedFieldNo(0, Elts);
741    const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
742    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
743    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
744  }
745
746  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
747}
748
749// setObjCGCLValueClass - sets class of he lvalue for the purpose of
750// generating write-barries API. It is currently a global, ivar,
751// or neither.
752static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
753                                 LValue &LV) {
754  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
755    return;
756
757  if (isa<ObjCIvarRefExpr>(E)) {
758    LV.SetObjCIvar(LV, true);
759    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
760    LV.setBaseIvarExp(Exp->getBase());
761    LV.SetObjCArray(LV, E->getType()->isArrayType());
762    return;
763  }
764
765  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
766    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
767      if ((VD->isBlockVarDecl() && !VD->hasLocalStorage()) ||
768          VD->isFileVarDecl())
769        LV.SetGlobalObjCRef(LV, true);
770    }
771    LV.SetObjCArray(LV, E->getType()->isArrayType());
772    return;
773  }
774
775  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
776    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
777    return;
778  }
779
780  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
781    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
782    if (LV.isObjCIvar()) {
783      // If cast is to a structure pointer, follow gcc's behavior and make it
784      // a non-ivar write-barrier.
785      QualType ExpTy = E->getType();
786      if (ExpTy->isPointerType())
787        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
788      if (ExpTy->isRecordType())
789        LV.SetObjCIvar(LV, false);
790    }
791    return;
792  }
793  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
794    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
795    return;
796  }
797
798  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
799    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
800    return;
801  }
802
803  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
804    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
805    if (LV.isObjCIvar() && !LV.isObjCArray())
806      // Using array syntax to assigning to what an ivar points to is not
807      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
808      LV.SetObjCIvar(LV, false);
809    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
810      // Using array syntax to assigning to what global points to is not
811      // same as assigning to the global itself. {id *G;} G[i] = 0;
812      LV.SetGlobalObjCRef(LV, false);
813    return;
814  }
815
816  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
817    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
818    // We don't know if member is an 'ivar', but this flag is looked at
819    // only in the context of LV.isObjCIvar().
820    LV.SetObjCArray(LV, E->getType()->isArrayType());
821    return;
822  }
823}
824
825static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
826                                      const Expr *E, const VarDecl *VD) {
827  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
828         "Var decl must have external storage or be a file var decl!");
829
830  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
831  if (VD->getType()->isReferenceType())
832    V = CGF.Builder.CreateLoad(V, "tmp");
833  LValue LV = LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
834  setObjCGCLValueClass(CGF.getContext(), E, LV);
835  return LV;
836}
837
838static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
839                                      const Expr *E, const FunctionDecl *FD) {
840  llvm::Value* V = CGF.CGM.GetAddrOfFunction(FD);
841  if (!FD->hasPrototype()) {
842    if (const FunctionProtoType *Proto =
843            FD->getType()->getAs<FunctionProtoType>()) {
844      // Ugly case: for a K&R-style definition, the type of the definition
845      // isn't the same as the type of a use.  Correct for this with a
846      // bitcast.
847      QualType NoProtoType =
848          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
849      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
850      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
851    }
852  }
853  return LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
854}
855
856LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
857  const NamedDecl *ND = E->getDecl();
858
859  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
860
861    // Check if this is a global variable.
862    if (VD->hasExternalStorage() || VD->isFileVarDecl())
863      return EmitGlobalVarDeclLValue(*this, E, VD);
864
865    bool NonGCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
866
867    llvm::Value *V = LocalDeclMap[VD];
868    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
869
870    Qualifiers Quals = MakeQualifiers(E->getType());
871    // local variables do not get their gc attribute set.
872    // local static?
873    if (NonGCable) Quals.removeObjCGCAttr();
874
875    if (VD->hasAttr<BlocksAttr>()) {
876      V = Builder.CreateStructGEP(V, 1, "forwarding");
877      V = Builder.CreateLoad(V);
878      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
879                                  VD->getNameAsString());
880    }
881    if (VD->getType()->isReferenceType())
882      V = Builder.CreateLoad(V, "tmp");
883    LValue LV = LValue::MakeAddr(V, Quals);
884    LValue::SetObjCNonGC(LV, NonGCable);
885    setObjCGCLValueClass(getContext(), E, LV);
886    return LV;
887  }
888
889  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
890    return EmitFunctionDeclLValue(*this, E, FD);
891
892  if (E->getQualifier()) {
893    // FIXME: the qualifier check does not seem sufficient here
894    return EmitPointerToDataMemberLValue(cast<FieldDecl>(ND));
895  }
896
897  assert(false && "Unhandled DeclRefExpr");
898
899  // an invalid LValue, but the assert will
900  // ensure that this point is never reached.
901  return LValue();
902}
903
904LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
905  return LValue::MakeAddr(GetAddrOfBlockDecl(E), MakeQualifiers(E->getType()));
906}
907
908LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
909  // __extension__ doesn't affect lvalue-ness.
910  if (E->getOpcode() == UnaryOperator::Extension)
911    return EmitLValue(E->getSubExpr());
912
913  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
914  switch (E->getOpcode()) {
915  default: assert(0 && "Unknown unary operator lvalue!");
916  case UnaryOperator::Deref: {
917    QualType T = E->getSubExpr()->getType()->getPointeeType();
918    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
919
920    Qualifiers Quals = MakeQualifiers(T);
921    Quals.setAddressSpace(ExprTy.getAddressSpace());
922
923    LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()), Quals);
924    // We should not generate __weak write barrier on indirect reference
925    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
926    // But, we continue to generate __strong write barrier on indirect write
927    // into a pointer to object.
928    if (getContext().getLangOptions().ObjC1 &&
929        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
930        LV.isObjCWeak())
931      LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
932    return LV;
933  }
934  case UnaryOperator::Real:
935  case UnaryOperator::Imag: {
936    LValue LV = EmitLValue(E->getSubExpr());
937    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
938    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
939                                                    Idx, "idx"),
940                            MakeQualifiers(ExprTy));
941  }
942  case UnaryOperator::PreInc:
943  case UnaryOperator::PreDec:
944    return EmitUnsupportedLValue(E, "pre-inc/dec expression");
945  }
946}
947
948LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
949  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E),
950                          Qualifiers());
951}
952
953LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
954  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E),
955                          Qualifiers());
956}
957
958
959LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
960  std::string GlobalVarName;
961
962  switch (Type) {
963  default: assert(0 && "Invalid type");
964  case PredefinedExpr::Func:
965    GlobalVarName = "__func__.";
966    break;
967  case PredefinedExpr::Function:
968    GlobalVarName = "__FUNCTION__.";
969    break;
970  case PredefinedExpr::PrettyFunction:
971    GlobalVarName = "__PRETTY_FUNCTION__.";
972    break;
973  }
974
975  llvm::StringRef FnName = CurFn->getName();
976  if (FnName.startswith("\01"))
977    FnName = FnName.substr(1);
978  GlobalVarName += FnName;
979
980  std::string FunctionName =
981    PredefinedExpr::ComputeName(getContext(), (PredefinedExpr::IdentType)Type,
982                                CurCodeDecl);
983
984  llvm::Constant *C =
985    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
986  return LValue::MakeAddr(C, Qualifiers());
987}
988
989LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
990  switch (E->getIdentType()) {
991  default:
992    return EmitUnsupportedLValue(E, "predefined expression");
993  case PredefinedExpr::Func:
994  case PredefinedExpr::Function:
995  case PredefinedExpr::PrettyFunction:
996    return EmitPredefinedFunctionName(E->getIdentType());
997  }
998}
999
1000LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1001  // The index must always be an integer, which is not an aggregate.  Emit it.
1002  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1003  QualType IdxTy  = E->getIdx()->getType();
1004  bool IdxSigned = IdxTy->isSignedIntegerType();
1005
1006  // If the base is a vector type, then we are forming a vector element lvalue
1007  // with this subscript.
1008  if (E->getBase()->getType()->isVectorType()) {
1009    // Emit the vector as an lvalue to get its address.
1010    LValue LHS = EmitLValue(E->getBase());
1011    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1012    Idx = Builder.CreateIntCast(Idx,
1013                          llvm::Type::getInt32Ty(VMContext), IdxSigned, "vidx");
1014    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1015                                 E->getBase()->getType().getCVRQualifiers());
1016  }
1017
1018  // The base must be a pointer, which is not an aggregate.  Emit it.
1019  llvm::Value *Base = EmitScalarExpr(E->getBase());
1020
1021  // Extend or truncate the index type to 32 or 64-bits.
1022  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1023  if (IdxBitwidth != LLVMPointerWidth)
1024    Idx = Builder.CreateIntCast(Idx,
1025                            llvm::IntegerType::get(VMContext, LLVMPointerWidth),
1026                                IdxSigned, "idxprom");
1027
1028  // We know that the pointer points to a type of the correct size, unless the
1029  // size is a VLA or Objective-C interface.
1030  llvm::Value *Address = 0;
1031  if (const VariableArrayType *VAT =
1032        getContext().getAsVariableArrayType(E->getType())) {
1033    llvm::Value *VLASize = GetVLASize(VAT);
1034
1035    Idx = Builder.CreateMul(Idx, VLASize);
1036
1037    QualType BaseType = getContext().getBaseElementType(VAT);
1038
1039    uint64_t BaseTypeSize = getContext().getTypeSize(BaseType) / 8;
1040    Idx = Builder.CreateUDiv(Idx,
1041                             llvm::ConstantInt::get(Idx->getType(),
1042                                                    BaseTypeSize));
1043    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1044  } else if (const ObjCInterfaceType *OIT =
1045             dyn_cast<ObjCInterfaceType>(E->getType())) {
1046    llvm::Value *InterfaceSize =
1047      llvm::ConstantInt::get(Idx->getType(),
1048                             getContext().getTypeSize(OIT) / 8);
1049
1050    Idx = Builder.CreateMul(Idx, InterfaceSize);
1051
1052    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1053    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1054                                Idx, "arrayidx");
1055    Address = Builder.CreateBitCast(Address, Base->getType());
1056  } else {
1057    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1058  }
1059
1060  QualType T = E->getBase()->getType()->getPointeeType();
1061  assert(!T.isNull() &&
1062         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1063
1064  Qualifiers Quals = MakeQualifiers(T);
1065  Quals.setAddressSpace(E->getBase()->getType().getAddressSpace());
1066
1067  LValue LV = LValue::MakeAddr(Address, Quals);
1068  if (getContext().getLangOptions().ObjC1 &&
1069      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1070    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1071    setObjCGCLValueClass(getContext(), E, LV);
1072  }
1073  return LV;
1074}
1075
1076static
1077llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1078                                       llvm::SmallVector<unsigned, 4> &Elts) {
1079  llvm::SmallVector<llvm::Constant *, 4> CElts;
1080
1081  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1082    CElts.push_back(llvm::ConstantInt::get(
1083                                   llvm::Type::getInt32Ty(VMContext), Elts[i]));
1084
1085  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1086}
1087
1088LValue CodeGenFunction::
1089EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1090  // Emit the base vector as an l-value.
1091  LValue Base;
1092
1093  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1094  if (!E->isArrow()) {
1095    assert(E->getBase()->getType()->isVectorType());
1096    Base = EmitLValue(E->getBase());
1097  } else {
1098    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1099    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1100    Qualifiers Quals = MakeQualifiers(PT->getPointeeType());
1101    Quals.removeObjCGCAttr();
1102    Base = LValue::MakeAddr(Ptr, Quals);
1103  }
1104
1105  // Encode the element access list into a vector of unsigned indices.
1106  llvm::SmallVector<unsigned, 4> Indices;
1107  E->getEncodedElementAccess(Indices);
1108
1109  if (Base.isSimple()) {
1110    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1111    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1112                                    Base.getVRQualifiers());
1113  }
1114  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1115
1116  llvm::Constant *BaseElts = Base.getExtVectorElts();
1117  llvm::SmallVector<llvm::Constant *, 4> CElts;
1118
1119  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1120  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1121    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1122      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1123    else
1124      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1125  }
1126  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1127  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1128                                  Base.getVRQualifiers());
1129}
1130
1131LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1132  bool isUnion = false;
1133  bool isNonGC = false;
1134  Expr *BaseExpr = E->getBase();
1135  llvm::Value *BaseValue = NULL;
1136  Qualifiers BaseQuals;
1137
1138  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1139  if (E->isArrow()) {
1140    BaseValue = EmitScalarExpr(BaseExpr);
1141    const PointerType *PTy =
1142      BaseExpr->getType()->getAs<PointerType>();
1143    if (PTy->getPointeeType()->isUnionType())
1144      isUnion = true;
1145    BaseQuals = PTy->getPointeeType().getQualifiers();
1146  } else if (isa<ObjCPropertyRefExpr>(BaseExpr->IgnoreParens()) ||
1147             isa<ObjCImplicitSetterGetterRefExpr>(
1148               BaseExpr->IgnoreParens())) {
1149    RValue RV = EmitObjCPropertyGet(BaseExpr);
1150    BaseValue = RV.getAggregateAddr();
1151    if (BaseExpr->getType()->isUnionType())
1152      isUnion = true;
1153    BaseQuals = BaseExpr->getType().getQualifiers();
1154  } else {
1155    LValue BaseLV = EmitLValue(BaseExpr);
1156    if (BaseLV.isNonGC())
1157      isNonGC = true;
1158    // FIXME: this isn't right for bitfields.
1159    BaseValue = BaseLV.getAddress();
1160    QualType BaseTy = BaseExpr->getType();
1161    if (BaseTy->isUnionType())
1162      isUnion = true;
1163    BaseQuals = BaseTy.getQualifiers();
1164  }
1165
1166  NamedDecl *ND = E->getMemberDecl();
1167  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1168    LValue LV = EmitLValueForField(BaseValue, Field, isUnion,
1169                                   BaseQuals.getCVRQualifiers());
1170    LValue::SetObjCNonGC(LV, isNonGC);
1171    setObjCGCLValueClass(getContext(), E, LV);
1172    return LV;
1173  }
1174
1175  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1176    return EmitGlobalVarDeclLValue(*this, E, VD);
1177
1178  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1179    return EmitFunctionDeclLValue(*this, E, FD);
1180
1181  assert(false && "Unhandled member declaration!");
1182  return LValue();
1183}
1184
1185LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
1186                                              const FieldDecl* Field,
1187                                              unsigned CVRQualifiers) {
1188  CodeGenTypes::BitFieldInfo Info = CGM.getTypes().getBitFieldInfo(Field);
1189
1190  // FIXME: CodeGenTypes should expose a method to get the appropriate type for
1191  // FieldTy (the appropriate type is ABI-dependent).
1192  const llvm::Type *FieldTy =
1193    CGM.getTypes().ConvertTypeForMem(Field->getType());
1194  const llvm::PointerType *BaseTy =
1195  cast<llvm::PointerType>(BaseValue->getType());
1196  unsigned AS = BaseTy->getAddressSpace();
1197  BaseValue = Builder.CreateBitCast(BaseValue,
1198                                    llvm::PointerType::get(FieldTy, AS),
1199                                    "tmp");
1200
1201  llvm::Value *Idx =
1202    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), Info.FieldNo);
1203  llvm::Value *V = Builder.CreateGEP(BaseValue, Idx, "tmp");
1204
1205  return LValue::MakeBitfield(V, Info.Start, Info.Size,
1206                              Field->getType()->isSignedIntegerType(),
1207                            Field->getType().getCVRQualifiers()|CVRQualifiers);
1208}
1209
1210LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
1211                                           const FieldDecl* Field,
1212                                           bool isUnion,
1213                                           unsigned CVRQualifiers) {
1214  if (Field->isBitField())
1215    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1216
1217  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
1218  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1219
1220  // Match union field type.
1221  if (isUnion) {
1222    const llvm::Type *FieldTy =
1223      CGM.getTypes().ConvertTypeForMem(Field->getType());
1224    const llvm::PointerType * BaseTy =
1225      cast<llvm::PointerType>(BaseValue->getType());
1226    unsigned AS = BaseTy->getAddressSpace();
1227    V = Builder.CreateBitCast(V,
1228                              llvm::PointerType::get(FieldTy, AS),
1229                              "tmp");
1230  }
1231  if (Field->getType()->isReferenceType())
1232    V = Builder.CreateLoad(V, "tmp");
1233
1234  Qualifiers Quals = MakeQualifiers(Field->getType());
1235  Quals.addCVRQualifiers(CVRQualifiers);
1236  // __weak attribute on a field is ignored.
1237  if (Quals.getObjCGCAttr() == Qualifiers::Weak)
1238    Quals.removeObjCGCAttr();
1239
1240  return LValue::MakeAddr(V, Quals);
1241}
1242
1243LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1244  const llvm::Type *LTy = ConvertType(E->getType());
1245  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
1246
1247  const Expr* InitExpr = E->getInitializer();
1248  LValue Result = LValue::MakeAddr(DeclPtr, MakeQualifiers(E->getType()));
1249
1250  if (E->getType()->isComplexType())
1251    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1252  else if (hasAggregateLLVMType(E->getType()))
1253    EmitAnyExpr(InitExpr, DeclPtr, false);
1254  else
1255    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1256
1257  return Result;
1258}
1259
1260LValue
1261CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator* E) {
1262  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
1263    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1264    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1265    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1266
1267    llvm::Value *Cond = EvaluateExprAsBool(E->getCond());
1268    Builder.CreateCondBr(Cond, LHSBlock, RHSBlock);
1269
1270    EmitBlock(LHSBlock);
1271
1272    LValue LHS = EmitLValue(E->getLHS());
1273    if (!LHS.isSimple())
1274      return EmitUnsupportedLValue(E, "conditional operator");
1275
1276    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1277    Builder.CreateStore(LHS.getAddress(), Temp);
1278    EmitBranch(ContBlock);
1279
1280    EmitBlock(RHSBlock);
1281    LValue RHS = EmitLValue(E->getRHS());
1282    if (!RHS.isSimple())
1283      return EmitUnsupportedLValue(E, "conditional operator");
1284
1285    Builder.CreateStore(RHS.getAddress(), Temp);
1286    EmitBranch(ContBlock);
1287
1288    EmitBlock(ContBlock);
1289
1290    Temp = Builder.CreateLoad(Temp, "lv");
1291    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1292  }
1293
1294  // ?: here should be an aggregate.
1295  assert((hasAggregateLLVMType(E->getType()) &&
1296          !E->getType()->isAnyComplexType()) &&
1297         "Unexpected conditional operator!");
1298
1299  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1300  EmitAggExpr(E, Temp, false);
1301
1302  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1303}
1304
1305/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1306/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1307/// otherwise if a cast is needed by the code generator in an lvalue context,
1308/// then it must mean that we need the address of an aggregate in order to
1309/// access one of its fields.  This can happen for all the reasons that casts
1310/// are permitted with aggregate result, including noop aggregate casts, and
1311/// cast from scalar to union.
1312LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1313  switch (E->getCastKind()) {
1314  default:
1315    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1316
1317  case CastExpr::CK_Dynamic: {
1318    LValue LV = EmitLValue(E->getSubExpr());
1319    llvm::Value *V = LV.getAddress();
1320    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1321    return LValue::MakeAddr(EmitDynamicCast(V, DCE),
1322                            MakeQualifiers(E->getType()));
1323  }
1324
1325  case CastExpr::CK_NoOp:
1326  case CastExpr::CK_ConstructorConversion:
1327  case CastExpr::CK_UserDefinedConversion:
1328    return EmitLValue(E->getSubExpr());
1329
1330  case CastExpr::CK_DerivedToBase: {
1331    const RecordType *DerivedClassTy =
1332      E->getSubExpr()->getType()->getAs<RecordType>();
1333    CXXRecordDecl *DerivedClassDecl =
1334      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1335
1336    const RecordType *BaseClassTy = E->getType()->getAs<RecordType>();
1337    CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseClassTy->getDecl());
1338
1339    LValue LV = EmitLValue(E->getSubExpr());
1340
1341    // Perform the derived-to-base conversion
1342    llvm::Value *Base =
1343      GetAddressOfBaseClass(LV.getAddress(), DerivedClassDecl,
1344                            BaseClassDecl, /*NullCheckValue=*/false);
1345
1346    return LValue::MakeAddr(Base, MakeQualifiers(E->getType()));
1347  }
1348  case CastExpr::CK_ToUnion: {
1349    llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1350    EmitAnyExpr(E->getSubExpr(), Temp, false);
1351
1352    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1353  }
1354  case CastExpr::CK_BaseToDerived: {
1355    const RecordType *BaseClassTy =
1356      E->getSubExpr()->getType()->getAs<RecordType>();
1357    CXXRecordDecl *BaseClassDecl =
1358      cast<CXXRecordDecl>(BaseClassTy->getDecl());
1359
1360    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1361    CXXRecordDecl *DerivedClassDecl =
1362      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1363
1364    LValue LV = EmitLValue(E->getSubExpr());
1365
1366    // Perform the base-to-derived conversion
1367    llvm::Value *Derived =
1368      GetAddressOfDerivedClass(LV.getAddress(), BaseClassDecl,
1369                               DerivedClassDecl, /*NullCheckValue=*/false);
1370
1371    return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
1372  }
1373  case CastExpr::CK_BitCast: {
1374    // This must be a reinterpret_cast (or c-style equivalent).
1375    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1376
1377    LValue LV = EmitLValue(E->getSubExpr());
1378    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1379                                           ConvertType(CE->getTypeAsWritten()));
1380    return LValue::MakeAddr(V, MakeQualifiers(E->getType()));
1381  }
1382  }
1383}
1384
1385LValue CodeGenFunction::EmitNullInitializationLValue(
1386                                              const CXXZeroInitValueExpr *E) {
1387  QualType Ty = E->getType();
1388  const llvm::Type *LTy = ConvertTypeForMem(Ty);
1389  llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
1390  unsigned Align = getContext().getTypeAlign(Ty)/8;
1391  Alloc->setAlignment(Align);
1392  LValue lvalue = LValue::MakeAddr(Alloc, Qualifiers());
1393  EmitMemSetToZero(lvalue.getAddress(), Ty);
1394  return lvalue;
1395}
1396
1397//===--------------------------------------------------------------------===//
1398//                             Expression Emission
1399//===--------------------------------------------------------------------===//
1400
1401
1402RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
1403  // Builtins never have block type.
1404  if (E->getCallee()->getType()->isBlockPointerType())
1405    return EmitBlockCallExpr(E);
1406
1407  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1408    return EmitCXXMemberCallExpr(CE);
1409
1410  const Decl *TargetDecl = 0;
1411  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1412    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1413      TargetDecl = DRE->getDecl();
1414      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1415        if (unsigned builtinID = FD->getBuiltinID())
1416          return EmitBuiltinExpr(FD, builtinID, E);
1417    }
1418  }
1419
1420  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1421    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1422      return EmitCXXOperatorMemberCallExpr(CE, MD);
1423
1424  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1425    // C++ [expr.pseudo]p1:
1426    //   The result shall only be used as the operand for the function call
1427    //   operator (), and the result of such a call has type void. The only
1428    //   effect is the evaluation of the postfix-expression before the dot or
1429    //   arrow.
1430    EmitScalarExpr(E->getCallee());
1431    return RValue::get(0);
1432  }
1433
1434  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1435  return EmitCall(Callee, E->getCallee()->getType(),
1436                  E->arg_begin(), E->arg_end(), TargetDecl);
1437}
1438
1439LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1440  // Comma expressions just emit their LHS then their RHS as an l-value.
1441  if (E->getOpcode() == BinaryOperator::Comma) {
1442    EmitAnyExpr(E->getLHS());
1443    EnsureInsertPoint();
1444    return EmitLValue(E->getRHS());
1445  }
1446
1447  if (E->getOpcode() == BinaryOperator::PtrMemD ||
1448      E->getOpcode() == BinaryOperator::PtrMemI)
1449    return EmitPointerToDataMemberBinaryExpr(E);
1450
1451  // Can only get l-value for binary operator expressions which are a
1452  // simple assignment of aggregate type.
1453  if (E->getOpcode() != BinaryOperator::Assign)
1454    return EmitUnsupportedLValue(E, "binary l-value expression");
1455
1456  if (!hasAggregateLLVMType(E->getType())) {
1457    // Emit the LHS as an l-value.
1458    LValue LV = EmitLValue(E->getLHS());
1459
1460    llvm::Value *RHS = EmitScalarExpr(E->getRHS());
1461    EmitStoreOfScalar(RHS, LV.getAddress(), LV.isVolatileQualified(),
1462                      E->getType());
1463    return LV;
1464  }
1465
1466  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1467  EmitAggExpr(E, Temp, false);
1468  // FIXME: Are these qualifiers correct?
1469  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1470}
1471
1472LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1473  RValue RV = EmitCallExpr(E);
1474
1475  if (!RV.isScalar())
1476    return LValue::MakeAddr(RV.getAggregateAddr(),MakeQualifiers(E->getType()));
1477
1478  assert(E->getCallReturnType()->isReferenceType() &&
1479         "Can't have a scalar return unless the return type is a "
1480         "reference type!");
1481
1482  return LValue::MakeAddr(RV.getScalarVal(), MakeQualifiers(E->getType()));
1483}
1484
1485LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1486  // FIXME: This shouldn't require another copy.
1487  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1488  EmitAggExpr(E, Temp, false);
1489  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1490}
1491
1492LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1493  llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()), "tmp");
1494  EmitCXXConstructExpr(Temp, E);
1495  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1496}
1497
1498LValue
1499CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1500  llvm::Value *Temp = EmitCXXTypeidExpr(E);
1501  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1502}
1503
1504LValue
1505CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1506  LValue LV = EmitLValue(E->getSubExpr());
1507  PushCXXTemporary(E->getTemporary(), LV.getAddress());
1508  return LV;
1509}
1510
1511LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1512  // Can only get l-value for message expression returning aggregate type
1513  RValue RV = EmitObjCMessageExpr(E);
1514  // FIXME: can this be volatile?
1515  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1516}
1517
1518llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1519                                             const ObjCIvarDecl *Ivar) {
1520  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1521}
1522
1523LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1524                                          llvm::Value *BaseValue,
1525                                          const ObjCIvarDecl *Ivar,
1526                                          unsigned CVRQualifiers) {
1527  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1528                                                   Ivar, CVRQualifiers);
1529}
1530
1531LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1532  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1533  llvm::Value *BaseValue = 0;
1534  const Expr *BaseExpr = E->getBase();
1535  Qualifiers BaseQuals;
1536  QualType ObjectTy;
1537  if (E->isArrow()) {
1538    BaseValue = EmitScalarExpr(BaseExpr);
1539    ObjectTy = BaseExpr->getType()->getPointeeType();
1540    BaseQuals = ObjectTy.getQualifiers();
1541  } else {
1542    LValue BaseLV = EmitLValue(BaseExpr);
1543    // FIXME: this isn't right for bitfields.
1544    BaseValue = BaseLV.getAddress();
1545    ObjectTy = BaseExpr->getType();
1546    BaseQuals = ObjectTy.getQualifiers();
1547  }
1548
1549  LValue LV =
1550    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1551                      BaseQuals.getCVRQualifiers());
1552  setObjCGCLValueClass(getContext(), E, LV);
1553  return LV;
1554}
1555
1556LValue
1557CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1558  // This is a special l-value that just issues sends when we load or store
1559  // through it.
1560  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1561}
1562
1563LValue CodeGenFunction::EmitObjCKVCRefLValue(
1564                                const ObjCImplicitSetterGetterRefExpr *E) {
1565  // This is a special l-value that just issues sends when we load or store
1566  // through it.
1567  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1568}
1569
1570LValue CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1571  return EmitUnsupportedLValue(E, "use of super");
1572}
1573
1574LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1575  // Can only get l-value for message expression returning aggregate type
1576  RValue RV = EmitAnyExprToTemp(E);
1577  // FIXME: can this be volatile?
1578  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1579}
1580
1581
1582LValue CodeGenFunction::EmitPointerToDataMemberLValue(const FieldDecl *Field) {
1583  const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(Field->getDeclContext());
1584  QualType NNSpecTy =
1585    getContext().getCanonicalType(
1586      getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(ClassDecl)));
1587  NNSpecTy = getContext().getPointerType(NNSpecTy);
1588  llvm::Value *V = llvm::Constant::getNullValue(ConvertType(NNSpecTy));
1589  LValue MemExpLV = EmitLValueForField(V, Field, /*isUnion=*/false,
1590                                       /*Qualifiers=*/0);
1591  const llvm::Type *ResultType = ConvertType(getContext().getPointerDiffType());
1592  V = Builder.CreatePtrToInt(MemExpLV.getAddress(), ResultType, "datamember");
1593  return LValue::MakeAddr(V, MakeQualifiers(Field->getType()));
1594}
1595
1596RValue CodeGenFunction::EmitCall(llvm::Value *Callee, QualType CalleeType,
1597                                 CallExpr::const_arg_iterator ArgBeg,
1598                                 CallExpr::const_arg_iterator ArgEnd,
1599                                 const Decl *TargetDecl) {
1600  // Get the actual function type. The callee type will always be a pointer to
1601  // function type or a block pointer type.
1602  assert(CalleeType->isFunctionPointerType() &&
1603         "Call must have function pointer type!");
1604
1605  CalleeType = getContext().getCanonicalType(CalleeType);
1606
1607  QualType FnType = cast<PointerType>(CalleeType)->getPointeeType();
1608  QualType ResultType = cast<FunctionType>(FnType)->getResultType();
1609
1610  CallArgList Args;
1611  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
1612
1613  // FIXME: We should not need to do this, it should be part of the function
1614  // type.
1615  unsigned CallingConvention = 0;
1616  if (const llvm::Function *F =
1617      dyn_cast<llvm::Function>(Callee->stripPointerCasts()))
1618    CallingConvention = F->getCallingConv();
1619  return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args,
1620                                                 CallingConvention),
1621                  Callee, Args, TargetDecl);
1622}
1623
1624LValue CodeGenFunction::
1625EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
1626  llvm::Value *BaseV;
1627  if (E->getOpcode() == BinaryOperator::PtrMemI)
1628    BaseV = EmitScalarExpr(E->getLHS());
1629  else
1630    BaseV = EmitLValue(E->getLHS()).getAddress();
1631  const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(getLLVMContext());
1632  BaseV = Builder.CreateBitCast(BaseV, i8Ty);
1633  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
1634  llvm::Value *AddV = Builder.CreateInBoundsGEP(BaseV, OffsetV, "add.ptr");
1635
1636  QualType Ty = E->getRHS()->getType();
1637  Ty = Ty->getAs<MemberPointerType>()->getPointeeType();
1638
1639  const llvm::Type *PType = ConvertType(getContext().getPointerType(Ty));
1640  AddV = Builder.CreateBitCast(AddV, PType);
1641  return LValue::MakeAddr(AddV, MakeQualifiers(Ty));
1642}
1643
1644