CGExpr.cpp revision b14095aa98c6fedd3625920c4ce834bcaf24d9f7 
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 char *Name) {
32  if (!Builder.isNamePreserving())
33    Name = "";
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
50/// the result should be returned.
51RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
52                                    bool isAggLocVolatile) {
53  if (!hasAggregateLLVMType(E->getType()))
54    return RValue::get(EmitScalarExpr(E));
55  else if (E->getType()->isAnyComplexType())
56    return RValue::getComplex(EmitComplexExpr(E));
57
58  EmitAggExpr(E, AggLoc, isAggLocVolatile);
59  return RValue::getAggregate(AggLoc);
60}
61
62/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result
63/// will always be accessible even if no aggregate location is
64/// provided.
65RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E, llvm::Value *AggLoc,
66                                          bool isAggLocVolatile) {
67  if (!AggLoc && hasAggregateLLVMType(E->getType()) &&
68      !E->getType()->isAnyComplexType())
69    AggLoc = CreateTempAlloca(ConvertType(E->getType()), "agg.tmp");
70  return EmitAnyExpr(E, AggLoc, isAggLocVolatile);
71}
72
73/// getAccessedFieldNo - Given an encoded value and a result number, return
74/// the input field number being accessed.
75unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
76                                             const llvm::Constant *Elts) {
77  if (isa<llvm::ConstantAggregateZero>(Elts))
78    return 0;
79
80  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
81}
82
83
84//===----------------------------------------------------------------------===//
85//                         LValue Expression Emission
86//===----------------------------------------------------------------------===//
87
88RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
89  if (Ty->isVoidType()) {
90    return RValue::get(0);
91  } else if (const ComplexType *CTy = Ty->getAsComplexType()) {
92    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
93    llvm::Value *U = llvm::UndefValue::get(EltTy);
94    return RValue::getComplex(std::make_pair(U, U));
95  } else if (hasAggregateLLVMType(Ty)) {
96    const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
97    return RValue::getAggregate(llvm::UndefValue::get(LTy));
98  } else {
99    return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
100  }
101}
102
103RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
104                                              const char *Name) {
105  ErrorUnsupported(E, Name);
106  return GetUndefRValue(E->getType());
107}
108
109LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
110                                              const char *Name) {
111  ErrorUnsupported(E, Name);
112  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
113  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
114                          E->getType().getCVRQualifiers(),
115                          getContext().getObjCGCAttrKind(E->getType()));
116}
117
118/// EmitLValue - Emit code to compute a designator that specifies the location
119/// of the expression.
120///
121/// This can return one of two things: a simple address or a bitfield
122/// reference.  In either case, the LLVM Value* in the LValue structure is
123/// guaranteed to be an LLVM pointer type.
124///
125/// If this returns a bitfield reference, nothing about the pointee type of
126/// the LLVM value is known: For example, it may not be a pointer to an
127/// integer.
128///
129/// If this returns a normal address, and if the lvalue's C type is fixed
130/// size, this method guarantees that the returned pointer type will point to
131/// an LLVM type of the same size of the lvalue's type.  If the lvalue has a
132/// variable length type, this is not possible.
133///
134LValue CodeGenFunction::EmitLValue(const Expr *E) {
135  switch (E->getStmtClass()) {
136  default: return EmitUnsupportedLValue(E, "l-value expression");
137
138  case Expr::BinaryOperatorClass:
139    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
140  case Expr::CallExprClass:
141  case Expr::CXXOperatorCallExprClass:
142    return EmitCallExprLValue(cast<CallExpr>(E));
143  case Expr::VAArgExprClass:
144    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
145  case Expr::DeclRefExprClass:
146  case Expr::QualifiedDeclRefExprClass:
147    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
148  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
149  case Expr::PredefinedExprClass:
150    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
151  case Expr::StringLiteralClass:
152    return EmitStringLiteralLValue(cast<StringLiteral>(E));
153  case Expr::ObjCEncodeExprClass:
154    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
155
156  case Expr::BlockDeclRefExprClass:
157    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
158
159  case Expr::CXXConditionDeclExprClass:
160    return EmitCXXConditionDeclLValue(cast<CXXConditionDeclExpr>(E));
161
162  case Expr::ObjCMessageExprClass:
163    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
164  case Expr::ObjCIvarRefExprClass:
165    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
166  case Expr::ObjCPropertyRefExprClass:
167    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
168  case Expr::ObjCKVCRefExprClass:
169    return EmitObjCKVCRefLValue(cast<ObjCKVCRefExpr>(E));
170  case Expr::ObjCSuperExprClass:
171    return EmitObjCSuperExpr(cast<ObjCSuperExpr>(E));
172
173  case Expr::UnaryOperatorClass:
174    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
175  case Expr::ArraySubscriptExprClass:
176    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
177  case Expr::ExtVectorElementExprClass:
178    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
179  case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
180  case Expr::CompoundLiteralExprClass:
181    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
182  case Expr::ConditionalOperatorClass:
183    return EmitConditionalOperator(cast<ConditionalOperator>(E));
184  case Expr::ChooseExprClass:
185    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
186  case Expr::ImplicitCastExprClass:
187  case Expr::CStyleCastExprClass:
188  case Expr::CXXFunctionalCastExprClass:
189  case Expr::CXXStaticCastExprClass:
190  case Expr::CXXDynamicCastExprClass:
191  case Expr::CXXReinterpretCastExprClass:
192  case Expr::CXXConstCastExprClass:
193    return EmitCastLValue(cast<CastExpr>(E));
194  case Expr::CXXTemporaryObjectExprClass:
195    return EmitCXXTemporaryObjectExprLValue(cast<CXXTemporaryObjectExpr>(E));
196  }
197}
198
199llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
200                                               QualType Ty) {
201  llvm::Value *V = Builder.CreateLoad(Addr, Volatile, "tmp");
202
203  // Bool can have different representation in memory than in
204  // registers.
205  if (Ty->isBooleanType())
206    if (V->getType() != llvm::Type::Int1Ty)
207      V = Builder.CreateTrunc(V, llvm::Type::Int1Ty, "tobool");
208
209  return V;
210}
211
212void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
213                                        bool Volatile) {
214  // Handle stores of types which have different representations in
215  // memory and as LLVM values.
216
217  // FIXME: We shouldn't be this loose, we should only do this
218  // conversion when we have a type we know has a different memory
219  // representation (e.g., bool).
220
221  const llvm::Type *SrcTy = Value->getType();
222  const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
223  if (DstPtr->getElementType() != SrcTy) {
224    const llvm::Type *MemTy =
225      llvm::PointerType::get(SrcTy, DstPtr->getAddressSpace());
226    Addr = Builder.CreateBitCast(Addr, MemTy, "storetmp");
227  }
228
229  Builder.CreateStore(Value, Addr, Volatile);
230}
231
232/// EmitLoadOfLValue - Given an expression that represents a value lvalue,
233/// this method emits the address of the lvalue, then loads the result as an
234/// rvalue, returning the rvalue.
235RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
236  if (LV.isObjCWeak()) {
237    // load of a __weak object.
238    llvm::Value *AddrWeakObj = LV.getAddress();
239    llvm::Value *read_weak = CGM.getObjCRuntime().EmitObjCWeakRead(*this,
240                                                                   AddrWeakObj);
241    return RValue::get(read_weak);
242  }
243
244  if (LV.isSimple()) {
245    llvm::Value *Ptr = LV.getAddress();
246    const llvm::Type *EltTy =
247      cast<llvm::PointerType>(Ptr->getType())->getElementType();
248
249    // Simple scalar l-value.
250    if (EltTy->isSingleValueType())
251      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
252                                          ExprType));
253
254    assert(ExprType->isFunctionType() && "Unknown scalar value");
255    return RValue::get(Ptr);
256  }
257
258  if (LV.isVectorElt()) {
259    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
260                                          LV.isVolatileQualified(), "tmp");
261    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
262                                                    "vecext"));
263  }
264
265  // If this is a reference to a subset of the elements of a vector, either
266  // shuffle the input or extract/insert them as appropriate.
267  if (LV.isExtVectorElt())
268    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
269
270  if (LV.isBitfield())
271    return EmitLoadOfBitfieldLValue(LV, ExprType);
272
273  if (LV.isPropertyRef())
274    return EmitLoadOfPropertyRefLValue(LV, ExprType);
275
276  assert(LV.isKVCRef() && "Unknown LValue type!");
277  return EmitLoadOfKVCRefLValue(LV, ExprType);
278}
279
280RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
281                                                 QualType ExprType) {
282  unsigned StartBit = LV.getBitfieldStartBit();
283  unsigned BitfieldSize = LV.getBitfieldSize();
284  llvm::Value *Ptr = LV.getBitfieldAddr();
285
286  const llvm::Type *EltTy =
287    cast<llvm::PointerType>(Ptr->getType())->getElementType();
288  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
289
290  // In some cases the bitfield may straddle two memory locations.
291  // Currently we load the entire bitfield, then do the magic to
292  // sign-extend it if necessary. This results in somewhat more code
293  // than necessary for the common case (one load), since two shifts
294  // accomplish both the masking and sign extension.
295  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
296  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
297
298  // Shift to proper location.
299  if (StartBit)
300    Val = Builder.CreateLShr(Val, llvm::ConstantInt::get(EltTy, StartBit),
301                             "bf.lo");
302
303  // Mask off unused bits.
304  llvm::Constant *LowMask =
305    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, LowBits));
306  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
307
308  // Fetch the high bits if necessary.
309  if (LowBits < BitfieldSize) {
310    unsigned HighBits = BitfieldSize - LowBits;
311    llvm::Value *HighPtr =
312      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
313                        "bf.ptr.hi");
314    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
315                                              LV.isVolatileQualified(),
316                                              "tmp");
317
318    // Mask off unused bits.
319    llvm::Constant *HighMask =
320      llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, HighBits));
321    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
322
323    // Shift to proper location and or in to bitfield value.
324    HighVal = Builder.CreateShl(HighVal,
325                                llvm::ConstantInt::get(EltTy, LowBits));
326    Val = Builder.CreateOr(Val, HighVal, "bf.val");
327  }
328
329  // Sign extend if necessary.
330  if (LV.isBitfieldSigned()) {
331    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
332                                                    EltTySize - BitfieldSize);
333    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
334                             ExtraBits, "bf.val.sext");
335  }
336
337  // The bitfield type and the normal type differ when the storage sizes
338  // differ (currently just _Bool).
339  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
340
341  return RValue::get(Val);
342}
343
344RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
345                                                    QualType ExprType) {
346  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
347}
348
349RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
350                                               QualType ExprType) {
351  return EmitObjCPropertyGet(LV.getKVCRefExpr());
352}
353
354// If this is a reference to a subset of the elements of a vector, create an
355// appropriate shufflevector.
356RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
357                                                         QualType ExprType) {
358  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
359                                        LV.isVolatileQualified(), "tmp");
360
361  const llvm::Constant *Elts = LV.getExtVectorElts();
362
363  // If the result of the expression is a non-vector type, we must be
364  // extracting a single element.  Just codegen as an extractelement.
365  const VectorType *ExprVT = ExprType->getAsVectorType();
366  if (!ExprVT) {
367    unsigned InIdx = getAccessedFieldNo(0, Elts);
368    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
369    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
370  }
371
372  // Always use shuffle vector to try to retain the original program structure
373  unsigned NumResultElts = ExprVT->getNumElements();
374
375  llvm::SmallVector<llvm::Constant*, 4> Mask;
376  for (unsigned i = 0; i != NumResultElts; ++i) {
377    unsigned InIdx = getAccessedFieldNo(i, Elts);
378    Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
379  }
380
381  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
382  Vec = Builder.CreateShuffleVector(Vec,
383                                    llvm::UndefValue::get(Vec->getType()),
384                                    MaskV, "tmp");
385  return RValue::get(Vec);
386}
387
388
389
390/// EmitStoreThroughLValue - Store the specified rvalue into the specified
391/// lvalue, where both are guaranteed to the have the same type, and that type
392/// is 'Ty'.
393void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
394                                             QualType Ty) {
395  if (!Dst.isSimple()) {
396    if (Dst.isVectorElt()) {
397      // Read/modify/write the vector, inserting the new element.
398      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
399                                            Dst.isVolatileQualified(), "tmp");
400      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
401                                        Dst.getVectorIdx(), "vecins");
402      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
403      return;
404    }
405
406    // If this is an update of extended vector elements, insert them as
407    // appropriate.
408    if (Dst.isExtVectorElt())
409      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
410
411    if (Dst.isBitfield())
412      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
413
414    if (Dst.isPropertyRef())
415      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
416
417    if (Dst.isKVCRef())
418      return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
419
420    assert(0 && "Unknown LValue type");
421  }
422
423  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
424    // load of a __weak object.
425    llvm::Value *LvalueDst = Dst.getAddress();
426    llvm::Value *src = Src.getScalarVal();
427     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
428    return;
429  }
430
431  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
432    // load of a __strong object.
433    llvm::Value *LvalueDst = Dst.getAddress();
434    llvm::Value *src = Src.getScalarVal();
435#if 0
436    // FIXME. We cannot positively determine if we have an
437    // 'ivar' assignment, object assignment or an unknown
438    // assignment. For now, generate call to objc_assign_strongCast
439    // assignment which is a safe, but consevative assumption.
440    if (Dst.isObjCIvar())
441      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, LvalueDst);
442    else
443      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
444#endif
445    CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
446    return;
447  }
448
449  assert(Src.isScalar() && "Can't emit an agg store with this method");
450  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
451                    Dst.isVolatileQualified());
452}
453
454void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
455                                                     QualType Ty,
456                                                     llvm::Value **Result) {
457  unsigned StartBit = Dst.getBitfieldStartBit();
458  unsigned BitfieldSize = Dst.getBitfieldSize();
459  llvm::Value *Ptr = Dst.getBitfieldAddr();
460
461  const llvm::Type *EltTy =
462    cast<llvm::PointerType>(Ptr->getType())->getElementType();
463  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
464
465  // Get the new value, cast to the appropriate type and masked to
466  // exactly the size of the bit-field.
467  llvm::Value *SrcVal = Src.getScalarVal();
468  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
469  llvm::Constant *Mask =
470    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
471  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
472
473  // Return the new value of the bit-field, if requested.
474  if (Result) {
475    // Cast back to the proper type for result.
476    const llvm::Type *SrcTy = SrcVal->getType();
477    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
478                                                  "bf.reload.val");
479
480    // Sign extend if necessary.
481    if (Dst.isBitfieldSigned()) {
482      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
483      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
484                                                      SrcTySize - BitfieldSize);
485      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
486                                    ExtraBits, "bf.reload.sext");
487    }
488
489    *Result = SrcTrunc;
490  }
491
492  // In some cases the bitfield may straddle two memory locations.
493  // Emit the low part first and check to see if the high needs to be
494  // done.
495  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
496  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
497                                           "bf.prev.low");
498
499  // Compute the mask for zero-ing the low part of this bitfield.
500  llvm::Constant *InvMask =
501    llvm::ConstantInt::get(~llvm::APInt::getBitsSet(EltTySize, StartBit,
502                                                    StartBit + LowBits));
503
504  // Compute the new low part as
505  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
506  // with the shift of NewVal implicitly stripping the high bits.
507  llvm::Value *NewLowVal =
508    Builder.CreateShl(NewVal, llvm::ConstantInt::get(EltTy, StartBit),
509                      "bf.value.lo");
510  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
511  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
512
513  // Write back.
514  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
515
516  // If the low part doesn't cover the bitfield emit a high part.
517  if (LowBits < BitfieldSize) {
518    unsigned HighBits = BitfieldSize - LowBits;
519    llvm::Value *HighPtr =
520      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
521                        "bf.ptr.hi");
522    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
523                                              Dst.isVolatileQualified(),
524                                              "bf.prev.hi");
525
526    // Compute the mask for zero-ing the high part of this bitfield.
527    llvm::Constant *InvMask =
528      llvm::ConstantInt::get(~llvm::APInt::getLowBitsSet(EltTySize, HighBits));
529
530    // Compute the new high part as
531    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
532    // where the high bits of NewVal have already been cleared and the
533    // shift stripping the low bits.
534    llvm::Value *NewHighVal =
535      Builder.CreateLShr(NewVal, llvm::ConstantInt::get(EltTy, LowBits),
536                        "bf.value.high");
537    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
538    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
539
540    // Write back.
541    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
542  }
543}
544
545void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
546                                                        LValue Dst,
547                                                        QualType Ty) {
548  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
549}
550
551void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
552                                                   LValue Dst,
553                                                   QualType Ty) {
554  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
555}
556
557void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
558                                                               LValue Dst,
559                                                               QualType Ty) {
560  // This access turns into a read/modify/write of the vector.  Load the input
561  // value now.
562  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
563                                        Dst.isVolatileQualified(), "tmp");
564  const llvm::Constant *Elts = Dst.getExtVectorElts();
565
566  llvm::Value *SrcVal = Src.getScalarVal();
567
568  if (const VectorType *VTy = Ty->getAsVectorType()) {
569    unsigned NumSrcElts = VTy->getNumElements();
570    unsigned NumDstElts =
571       cast<llvm::VectorType>(Vec->getType())->getNumElements();
572    if (NumDstElts == NumSrcElts) {
573      // Use shuffle vector is the src and destination are the same number
574      // of elements
575      llvm::SmallVector<llvm::Constant*, 4> Mask;
576      for (unsigned i = 0; i != NumSrcElts; ++i) {
577        unsigned InIdx = getAccessedFieldNo(i, Elts);
578        Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
579      }
580
581      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
582      Vec = Builder.CreateShuffleVector(SrcVal,
583                                        llvm::UndefValue::get(Vec->getType()),
584                                        MaskV, "tmp");
585    }
586    else if (NumDstElts > NumSrcElts) {
587      // Extended the source vector to the same length and then shuffle it
588      // into the destination.
589      // FIXME: since we're shuffling with undef, can we just use the indices
590      //        into that?  This could be simpler.
591      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
592      unsigned i;
593      for (i = 0; i != NumSrcElts; ++i)
594        ExtMask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
595      for (; i != NumDstElts; ++i)
596        ExtMask.push_back(llvm::UndefValue::get(llvm::Type::Int32Ty));
597      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
598                                                        ExtMask.size());
599      llvm::Value *ExtSrcVal =
600        Builder.CreateShuffleVector(SrcVal,
601                                    llvm::UndefValue::get(SrcVal->getType()),
602                                    ExtMaskV, "tmp");
603      // build identity
604      llvm::SmallVector<llvm::Constant*, 4> Mask;
605      for (unsigned i = 0; i != NumDstElts; ++i) {
606        Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
607      }
608      // modify when what gets shuffled in
609      for (unsigned i = 0; i != NumSrcElts; ++i) {
610        unsigned Idx = getAccessedFieldNo(i, Elts);
611        Mask[Idx] =llvm::ConstantInt::get(llvm::Type::Int32Ty, i+NumDstElts);
612      }
613      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
614      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
615    }
616    else {
617      // We should never shorten the vector
618      assert(0 && "unexpected shorten vector length");
619    }
620  } else {
621    // If the Src is a scalar (not a vector) it must be updating one element.
622    unsigned InIdx = getAccessedFieldNo(0, Elts);
623    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
624    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
625  }
626
627  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
628}
629
630LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
631  const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
632
633  if (VD && (VD->isBlockVarDecl() || isa<ParmVarDecl>(VD) ||
634        isa<ImplicitParamDecl>(VD))) {
635    LValue LV;
636    bool GCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
637    if (VD->hasExternalStorage()) {
638      LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
639                            E->getType().getCVRQualifiers(),
640                            getContext().getObjCGCAttrKind(E->getType()));
641    }
642    else {
643      llvm::Value *V = LocalDeclMap[VD];
644      assert(V && "DeclRefExpr not entered in LocalDeclMap?");
645      // local variables do not get their gc attribute set.
646      QualType::GCAttrTypes attr = QualType::GCNone;
647      // local static?
648      if (!GCable)
649        attr = getContext().getObjCGCAttrKind(E->getType());
650      if (VD->hasAttr<BlocksAttr>()) {
651        bool needsCopyDispose = BlockRequiresCopying(VD->getType());
652        const llvm::Type *PtrStructTy = V->getType();
653        const llvm::Type *Ty = PtrStructTy;
654        Ty = llvm::PointerType::get(Ty, 0);
655        V = Builder.CreateStructGEP(V, 1, "forwarding");
656        V = Builder.CreateBitCast(V, Ty);
657        V = Builder.CreateLoad(V, false);
658        V = Builder.CreateBitCast(V, PtrStructTy);
659        V = Builder.CreateStructGEP(V, needsCopyDispose*2 + 4, "x");
660      }
661      LV = LValue::MakeAddr(V, E->getType().getCVRQualifiers(), attr);
662    }
663    LValue::SetObjCNonGC(LV, GCable);
664    return LV;
665  } else if (VD && VD->isFileVarDecl()) {
666    LValue LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
667                                 E->getType().getCVRQualifiers(),
668                                 getContext().getObjCGCAttrKind(E->getType()));
669    return LV;
670  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) {
671    return LValue::MakeAddr(CGM.GetAddrOfFunction(FD),
672                            E->getType().getCVRQualifiers(),
673                            getContext().getObjCGCAttrKind(E->getType()));
674  }
675  else if (const ImplicitParamDecl *IPD =
676      dyn_cast<ImplicitParamDecl>(E->getDecl())) {
677    llvm::Value *V = LocalDeclMap[IPD];
678    assert(V && "BlockVarDecl not entered in LocalDeclMap?");
679    return LValue::MakeAddr(V, E->getType().getCVRQualifiers(),
680                            getContext().getObjCGCAttrKind(E->getType()));
681  }
682  assert(0 && "Unimp declref");
683  //an invalid LValue, but the assert will
684  //ensure that this point is never reached.
685  return LValue();
686}
687
688LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
689  return LValue::MakeAddr(GetAddrOfBlockDecl(E), 0);
690}
691
692LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
693  // __extension__ doesn't affect lvalue-ness.
694  if (E->getOpcode() == UnaryOperator::Extension)
695    return EmitLValue(E->getSubExpr());
696
697  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
698  switch (E->getOpcode()) {
699  default: assert(0 && "Unknown unary operator lvalue!");
700  case UnaryOperator::Deref:
701    {
702      QualType T =
703        E->getSubExpr()->getType()->getAsPointerType()->getPointeeType();
704      LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()),
705                                   ExprTy->getAsPointerType()->getPointeeType()
706                                      .getCVRQualifiers(),
707                                   getContext().getObjCGCAttrKind(T));
708     // We should not generate __weak write barrier on indirect reference
709     // of a pointer to object; as in void foo (__weak id *param); *param = 0;
710     // But, we continue to generate __strong write barrier on indirect write
711     // into a pointer to object.
712     if (getContext().getLangOptions().ObjC1 &&
713         getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
714         LV.isObjCWeak())
715       LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate());
716     return LV;
717    }
718  case UnaryOperator::Real:
719  case UnaryOperator::Imag:
720    LValue LV = EmitLValue(E->getSubExpr());
721    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
722    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
723                                                    Idx, "idx"),
724                            ExprTy.getCVRQualifiers());
725  }
726}
727
728LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
729  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E), 0);
730}
731
732LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
733  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E), 0);
734}
735
736
737LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
738  std::string GlobalVarName;
739
740  switch (Type) {
741  default:
742    assert(0 && "Invalid type");
743  case PredefinedExpr::Func:
744    GlobalVarName = "__func__.";
745    break;
746  case PredefinedExpr::Function:
747    GlobalVarName = "__FUNCTION__.";
748    break;
749  case PredefinedExpr::PrettyFunction:
750    // FIXME:: Demangle C++ method names
751    GlobalVarName = "__PRETTY_FUNCTION__.";
752    break;
753  }
754
755  std::string FunctionName;
756  if(const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurFuncDecl)) {
757    FunctionName = CGM.getMangledName(FD);
758  } else {
759    // Just get the mangled name; skipping the asm prefix if it
760    // exists.
761    FunctionName = CurFn->getName();
762    if (FunctionName[0] == '\01')
763      FunctionName = FunctionName.substr(1, std::string::npos);
764  }
765
766  GlobalVarName += FunctionName;
767  llvm::Constant *C =
768    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
769  return LValue::MakeAddr(C, 0);
770}
771
772LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
773  switch (E->getIdentType()) {
774  default:
775    return EmitUnsupportedLValue(E, "predefined expression");
776  case PredefinedExpr::Func:
777  case PredefinedExpr::Function:
778  case PredefinedExpr::PrettyFunction:
779    return EmitPredefinedFunctionName(E->getIdentType());
780  }
781}
782
783LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
784  // The index must always be an integer, which is not an aggregate.  Emit it.
785  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
786
787  // If the base is a vector type, then we are forming a vector element lvalue
788  // with this subscript.
789  if (E->getBase()->getType()->isVectorType()) {
790    // Emit the vector as an lvalue to get its address.
791    LValue LHS = EmitLValue(E->getBase());
792    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
793    // FIXME: This should properly sign/zero/extend or truncate Idx to i32.
794    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
795      E->getBase()->getType().getCVRQualifiers());
796  }
797
798  // The base must be a pointer, which is not an aggregate.  Emit it.
799  llvm::Value *Base = EmitScalarExpr(E->getBase());
800
801  // Extend or truncate the index type to 32 or 64-bits.
802  QualType IdxTy  = E->getIdx()->getType();
803  bool IdxSigned = IdxTy->isSignedIntegerType();
804  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
805
806  // If Pointer width is less than 32 than extend to 32.
807  unsigned IdxValidWidth = (LLVMPointerWidth < 32 ) ? 32 : LLVMPointerWidth;
808  if (IdxBitwidth != IdxValidWidth)
809    Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(IdxValidWidth),
810                                IdxSigned, "idxprom");
811
812  // We know that the pointer points to a type of the correct size, unless the
813  // size is a VLA.
814  if (const VariableArrayType *VAT =
815        getContext().getAsVariableArrayType(E->getType())) {
816    llvm::Value *VLASize = VLASizeMap[VAT];
817
818    Idx = Builder.CreateMul(Idx, VLASize);
819
820    QualType BaseType = getContext().getBaseElementType(VAT);
821
822    uint64_t BaseTypeSize = getContext().getTypeSize(BaseType) / 8;
823    Idx = Builder.CreateUDiv(Idx,
824                             llvm::ConstantInt::get(Idx->getType(),
825                                                    BaseTypeSize));
826  }
827
828  QualType T = E->getBase()->getType();
829  QualType ExprTy = getContext().getCanonicalType(T);
830  T = T->getAsPointerType()->getPointeeType();
831  LValue LV =
832           LValue::MakeAddr(Builder.CreateGEP(Base, Idx, "arrayidx"),
833           ExprTy->getAsPointerType()->getPointeeType().getCVRQualifiers(),
834           getContext().getObjCGCAttrKind(T));
835  if (getContext().getLangOptions().ObjC1 &&
836      getContext().getLangOptions().getGCMode() != LangOptions::NonGC)
837    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate());
838  return LV;
839}
840
841static
842llvm::Constant *GenerateConstantVector(llvm::SmallVector<unsigned, 4> &Elts) {
843  llvm::SmallVector<llvm::Constant *, 4> CElts;
844
845  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
846    CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, Elts[i]));
847
848  return llvm::ConstantVector::get(&CElts[0], CElts.size());
849}
850
851LValue CodeGenFunction::
852EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
853  // Emit the base vector as an l-value.
854  LValue Base;
855
856  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
857  if (!E->isArrow()) {
858    assert(E->getBase()->getType()->isVectorType());
859    Base = EmitLValue(E->getBase());
860  } else {
861    const PointerType *PT = E->getBase()->getType()->getAsPointerType();
862    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
863    Base = LValue::MakeAddr(Ptr, PT->getPointeeType().getCVRQualifiers());
864  }
865
866  // Encode the element access list into a vector of unsigned indices.
867  llvm::SmallVector<unsigned, 4> Indices;
868  E->getEncodedElementAccess(Indices);
869
870  if (Base.isSimple()) {
871    llvm::Constant *CV = GenerateConstantVector(Indices);
872    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
873                                    Base.getQualifiers());
874  }
875  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
876
877  llvm::Constant *BaseElts = Base.getExtVectorElts();
878  llvm::SmallVector<llvm::Constant *, 4> CElts;
879
880  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
881    if (isa<llvm::ConstantAggregateZero>(BaseElts))
882      CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
883    else
884      CElts.push_back(BaseElts->getOperand(Indices[i]));
885  }
886  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
887  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
888                                  Base.getQualifiers());
889}
890
891LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
892  bool isUnion = false;
893  bool isIvar = false;
894  bool isNonGC = false;
895  Expr *BaseExpr = E->getBase();
896  llvm::Value *BaseValue = NULL;
897  unsigned CVRQualifiers=0;
898
899  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
900  if (E->isArrow()) {
901    BaseValue = EmitScalarExpr(BaseExpr);
902    const PointerType *PTy =
903      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
904    if (PTy->getPointeeType()->isUnionType())
905      isUnion = true;
906    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
907  } else if (isa<ObjCPropertyRefExpr>(BaseExpr) ||
908             isa<ObjCKVCRefExpr>(BaseExpr)) {
909    RValue RV = EmitObjCPropertyGet(BaseExpr);
910    BaseValue = RV.getAggregateAddr();
911    if (BaseExpr->getType()->isUnionType())
912      isUnion = true;
913    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
914  } else {
915    LValue BaseLV = EmitLValue(BaseExpr);
916    if (BaseLV.isObjCIvar())
917      isIvar = true;
918    if (BaseLV.isNonGC())
919      isNonGC = true;
920    // FIXME: this isn't right for bitfields.
921    BaseValue = BaseLV.getAddress();
922    if (BaseExpr->getType()->isUnionType())
923      isUnion = true;
924    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
925  }
926
927  FieldDecl *Field = dyn_cast<FieldDecl>(E->getMemberDecl());
928  // FIXME: Handle non-field member expressions
929  assert(Field && "No code generation for non-field member references");
930  LValue MemExpLV = EmitLValueForField(BaseValue, Field, isUnion,
931                                       CVRQualifiers);
932  LValue::SetObjCIvar(MemExpLV, isIvar);
933  LValue::SetObjCNonGC(MemExpLV, isNonGC);
934  return MemExpLV;
935}
936
937LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
938                                              FieldDecl* Field,
939                                              unsigned CVRQualifiers) {
940   unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
941  // FIXME: CodeGenTypes should expose a method to get the appropriate
942  // type for FieldTy (the appropriate type is ABI-dependent).
943  const llvm::Type *FieldTy =
944    CGM.getTypes().ConvertTypeForMem(Field->getType());
945  const llvm::PointerType *BaseTy =
946  cast<llvm::PointerType>(BaseValue->getType());
947  unsigned AS = BaseTy->getAddressSpace();
948  BaseValue = Builder.CreateBitCast(BaseValue,
949                                    llvm::PointerType::get(FieldTy, AS),
950                                    "tmp");
951  llvm::Value *V = Builder.CreateGEP(BaseValue,
952                              llvm::ConstantInt::get(llvm::Type::Int32Ty, idx),
953                              "tmp");
954
955  CodeGenTypes::BitFieldInfo bitFieldInfo =
956    CGM.getTypes().getBitFieldInfo(Field);
957  return LValue::MakeBitfield(V, bitFieldInfo.Begin, bitFieldInfo.Size,
958                              Field->getType()->isSignedIntegerType(),
959                            Field->getType().getCVRQualifiers()|CVRQualifiers);
960}
961
962LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
963                                           FieldDecl* Field,
964                                           bool isUnion,
965                                           unsigned CVRQualifiers)
966{
967  if (Field->isBitField())
968    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
969
970  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
971  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
972
973  // Match union field type.
974  if (isUnion) {
975    const llvm::Type *FieldTy =
976      CGM.getTypes().ConvertTypeForMem(Field->getType());
977    const llvm::PointerType * BaseTy =
978      cast<llvm::PointerType>(BaseValue->getType());
979    unsigned AS = BaseTy->getAddressSpace();
980    V = Builder.CreateBitCast(V,
981                              llvm::PointerType::get(FieldTy, AS),
982                              "tmp");
983  }
984
985  QualType::GCAttrTypes attr = QualType::GCNone;
986  if (CGM.getLangOptions().ObjC1 &&
987      CGM.getLangOptions().getGCMode() != LangOptions::NonGC) {
988    QualType Ty = Field->getType();
989    attr = Ty.getObjCGCAttr();
990    if (attr != QualType::GCNone) {
991      // __weak attribute on a field is ignored.
992      if (attr == QualType::Weak)
993        attr = QualType::GCNone;
994    }
995    else if (getContext().isObjCObjectPointerType(Ty))
996      attr = QualType::Strong;
997  }
998  LValue LV =
999    LValue::MakeAddr(V,
1000                     Field->getType().getCVRQualifiers()|CVRQualifiers,
1001                     attr);
1002  return LV;
1003}
1004
1005LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1006  const llvm::Type *LTy = ConvertType(E->getType());
1007  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
1008
1009  const Expr* InitExpr = E->getInitializer();
1010  LValue Result = LValue::MakeAddr(DeclPtr, E->getType().getCVRQualifiers());
1011
1012  if (E->getType()->isComplexType()) {
1013    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1014  } else if (hasAggregateLLVMType(E->getType())) {
1015    EmitAnyExpr(InitExpr, DeclPtr, false);
1016  } else {
1017    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1018  }
1019
1020  return Result;
1021}
1022
1023LValue CodeGenFunction::EmitConditionalOperator(const ConditionalOperator* E) {
1024  // We don't handle vectors yet.
1025  if (E->getType()->isVectorType())
1026    return EmitUnsupportedLValue(E, "conditional operator");
1027
1028  // ?: here should be an aggregate.
1029  assert((hasAggregateLLVMType(E->getType()) &&
1030          !E->getType()->isAnyComplexType()) &&
1031         "Unexpected conditional operator!");
1032
1033  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1034  EmitAggExpr(E, Temp, false);
1035
1036  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1037                          getContext().getObjCGCAttrKind(E->getType()));
1038
1039}
1040
1041/// EmitCastLValue - Casts are never lvalues.  If a cast is needed by the code
1042/// generator in an lvalue context, then it must mean that we need the address
1043/// of an aggregate in order to access one of its fields.  This can happen for
1044/// all the reasons that casts are permitted with aggregate result, including
1045/// noop aggregate casts, and cast from scalar to union.
1046LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1047  // If this is an aggregate-to-aggregate cast, just use the input's address as
1048  // the lvalue.
1049  if (getContext().hasSameUnqualifiedType(E->getType(),
1050                                          E->getSubExpr()->getType()))
1051    return EmitLValue(E->getSubExpr());
1052
1053  // Otherwise, we must have a cast from scalar to union.
1054  assert(E->getType()->isUnionType() && "Expected scalar-to-union cast");
1055
1056  // Casts are only lvalues when the source and destination types are the same.
1057  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1058  EmitAnyExpr(E->getSubExpr(), Temp, false);
1059
1060  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1061                          getContext().getObjCGCAttrKind(E->getType()));
1062}
1063
1064//===--------------------------------------------------------------------===//
1065//                             Expression Emission
1066//===--------------------------------------------------------------------===//
1067
1068
1069RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
1070  // Builtins never have block type.
1071  if (E->getCallee()->getType()->isBlockPointerType())
1072    return EmitBlockCallExpr(E);
1073
1074  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1075    return EmitCXXMemberCallExpr(CE);
1076
1077  const Decl *TargetDecl = 0;
1078  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1079    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1080      TargetDecl = DRE->getDecl();
1081      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1082        if (unsigned builtinID = FD->getBuiltinID(getContext()))
1083          return EmitBuiltinExpr(FD, builtinID, E);
1084    }
1085  }
1086
1087  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1088  return EmitCallExpr(Callee, E->getCallee()->getType(),
1089                      E->arg_begin(), E->arg_end(), TargetDecl);
1090}
1091
1092LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1093  // Can only get l-value for binary operator expressions which are a
1094  // simple assignment of aggregate type.
1095  if (E->getOpcode() != BinaryOperator::Assign)
1096    return EmitUnsupportedLValue(E, "binary l-value expression");
1097
1098  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1099  EmitAggExpr(E, Temp, false);
1100  // FIXME: Are these qualifiers correct?
1101  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1102                          getContext().getObjCGCAttrKind(E->getType()));
1103}
1104
1105LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1106  // Can only get l-value for call expression returning aggregate type
1107  RValue RV = EmitCallExpr(E);
1108  return LValue::MakeAddr(RV.getAggregateAddr(),
1109                          E->getType().getCVRQualifiers(),
1110                          getContext().getObjCGCAttrKind(E->getType()));
1111}
1112
1113LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1114  // FIXME: This shouldn't require another copy.
1115  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1116  EmitAggExpr(E, Temp, false);
1117  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers());
1118}
1119
1120LValue
1121CodeGenFunction::EmitCXXConditionDeclLValue(const CXXConditionDeclExpr *E) {
1122  EmitLocalBlockVarDecl(*E->getVarDecl());
1123  return EmitDeclRefLValue(E);
1124}
1125
1126LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1127  // Can only get l-value for message expression returning aggregate type
1128  RValue RV = EmitObjCMessageExpr(E);
1129  // FIXME: can this be volatile?
1130  return LValue::MakeAddr(RV.getAggregateAddr(),
1131                          E->getType().getCVRQualifiers(),
1132                          getContext().getObjCGCAttrKind(E->getType()));
1133}
1134
1135llvm::Value *CodeGenFunction::EmitIvarOffset(ObjCInterfaceDecl *Interface,
1136                                             const ObjCIvarDecl *Ivar) {
1137  // Objective-C objects are traditionally C structures with their layout
1138  // defined at compile-time.  In some implementations, their layout is not
1139  // defined until run time in order to allow instance variables to be added to
1140  // a class without recompiling all of the subclasses.  If this is the case
1141  // then the CGObjCRuntime subclass must return true to LateBoundIvars and
1142  // implement the lookup itself.
1143  if (CGM.getObjCRuntime().LateBoundIVars())
1144    assert(0 && "late-bound ivars are unsupported");
1145  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1146}
1147
1148LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1149                                          llvm::Value *BaseValue,
1150                                          const ObjCIvarDecl *Ivar,
1151                                          const FieldDecl *Field,
1152                                          unsigned CVRQualifiers) {
1153  // See comment in EmitIvarOffset.
1154  if (CGM.getObjCRuntime().LateBoundIVars())
1155    assert(0 && "late-bound ivars are unsupported");
1156
1157  LValue LV = CGM.getObjCRuntime().EmitObjCValueForIvar(*this,
1158                                                        ObjectTy,
1159                                                        BaseValue, Ivar, Field,
1160                                                        CVRQualifiers);
1161  return LV;
1162}
1163
1164LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1165  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1166  llvm::Value *BaseValue = 0;
1167  const Expr *BaseExpr = E->getBase();
1168  unsigned CVRQualifiers = 0;
1169  QualType ObjectTy;
1170  if (E->isArrow()) {
1171    BaseValue = EmitScalarExpr(BaseExpr);
1172    const PointerType *PTy =
1173      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
1174    ObjectTy = PTy->getPointeeType();
1175    CVRQualifiers = ObjectTy.getCVRQualifiers();
1176  } else {
1177    LValue BaseLV = EmitLValue(BaseExpr);
1178    // FIXME: this isn't right for bitfields.
1179    BaseValue = BaseLV.getAddress();
1180    ObjectTy = BaseExpr->getType();
1181    CVRQualifiers = ObjectTy.getCVRQualifiers();
1182  }
1183
1184  return EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1185                           getContext().getFieldDecl(E), CVRQualifiers);
1186}
1187
1188LValue
1189CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1190  // This is a special l-value that just issues sends when we load or
1191  // store through it.
1192  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1193}
1194
1195LValue
1196CodeGenFunction::EmitObjCKVCRefLValue(const ObjCKVCRefExpr *E) {
1197  // This is a special l-value that just issues sends when we load or
1198  // store through it.
1199  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1200}
1201
1202LValue
1203CodeGenFunction::EmitObjCSuperExpr(const ObjCSuperExpr *E) {
1204  return EmitUnsupportedLValue(E, "use of super");
1205}
1206
1207RValue CodeGenFunction::EmitCallExpr(llvm::Value *Callee, QualType CalleeType,
1208                                     CallExpr::const_arg_iterator ArgBeg,
1209                                     CallExpr::const_arg_iterator ArgEnd,
1210                                     const Decl *TargetDecl) {
1211  // Get the actual function type. The callee type will always be a
1212  // pointer to function type or a block pointer type.
1213  assert(CalleeType->isFunctionPointerType() &&
1214         "Call must have function pointer type!");
1215
1216  QualType FnType = CalleeType->getAsPointerType()->getPointeeType();
1217  QualType ResultType = FnType->getAsFunctionType()->getResultType();
1218
1219  CallArgList Args;
1220  EmitCallArgs(Args, FnType->getAsFunctionProtoType(), ArgBeg, ArgEnd);
1221
1222  return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args),
1223                  Callee, Args, TargetDecl);
1224}
1225