CGExpr.cpp revision 1c698e0d4f9bf3d141c019d33d9040085a8a67dd 
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, bool IgnoreResult) {
53  if (!hasAggregateLLVMType(E->getType()))
54    return RValue::get(EmitScalarExpr(E, IgnoreResult));
55  else if (E->getType()->isAnyComplexType())
56    return RValue::getComplex(EmitComplexExpr(E, false, false,
57                                              IgnoreResult, IgnoreResult));
58
59  EmitAggExpr(E, AggLoc, isAggLocVolatile, IgnoreResult);
60  return RValue::getAggregate(AggLoc, isAggLocVolatile);
61}
62
63/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result
64/// will always be accessible even if no aggregate location is
65/// provided.
66RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E, llvm::Value *AggLoc,
67                                          bool isAggLocVolatile) {
68  if (!AggLoc && hasAggregateLLVMType(E->getType()) &&
69      !E->getType()->isAnyComplexType())
70    AggLoc = CreateTempAlloca(ConvertType(E->getType()), "agg.tmp");
71  return EmitAnyExpr(E, AggLoc, isAggLocVolatile);
72}
73
74RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr* E,
75                                                   QualType DestType) {
76  RValue Val;
77  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
78    // Emit the expr as an lvalue.
79    LValue LV = EmitLValue(E);
80    if (LV.isSimple())
81      return RValue::get(LV.getAddress());
82    Val = EmitLoadOfLValue(LV, E->getType());
83  } else {
84    Val = EmitAnyExprToTemp(E);
85  }
86
87  if (Val.isAggregate()) {
88    Val = RValue::get(Val.getAggregateAddr());
89  } else {
90    // Create a temporary variable that we can bind the reference to.
91    llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()),
92                                         "reftmp");
93    if (Val.isScalar())
94      EmitStoreOfScalar(Val.getScalarVal(), Temp, false, E->getType());
95    else
96      StoreComplexToAddr(Val.getComplexVal(), Temp, false);
97    Val = RValue::get(Temp);
98  }
99
100  return Val;
101}
102
103
104/// getAccessedFieldNo - Given an encoded value and a result number, return
105/// the input field number being accessed.
106unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
107                                             const llvm::Constant *Elts) {
108  if (isa<llvm::ConstantAggregateZero>(Elts))
109    return 0;
110
111  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
112}
113
114
115//===----------------------------------------------------------------------===//
116//                         LValue Expression Emission
117//===----------------------------------------------------------------------===//
118
119RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
120  if (Ty->isVoidType()) {
121    return RValue::get(0);
122  } else if (const ComplexType *CTy = Ty->getAsComplexType()) {
123    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
124    llvm::Value *U = VMContext.getUndef(EltTy);
125    return RValue::getComplex(std::make_pair(U, U));
126  } else if (hasAggregateLLVMType(Ty)) {
127    const llvm::Type *LTy = VMContext.getPointerTypeUnqual(ConvertType(Ty));
128    return RValue::getAggregate(VMContext.getUndef(LTy));
129  } else {
130    return RValue::get(VMContext.getUndef(ConvertType(Ty)));
131  }
132}
133
134RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
135                                              const char *Name) {
136  ErrorUnsupported(E, Name);
137  return GetUndefRValue(E->getType());
138}
139
140LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
141                                              const char *Name) {
142  ErrorUnsupported(E, Name);
143  llvm::Type *Ty = VMContext.getPointerTypeUnqual(ConvertType(E->getType()));
144  return LValue::MakeAddr(VMContext.getUndef(Ty),
145                          E->getType().getCVRQualifiers(),
146                          getContext().getObjCGCAttrKind(E->getType()),
147                          E->getType().getAddressSpace());
148}
149
150/// EmitLValue - Emit code to compute a designator that specifies the location
151/// of the expression.
152///
153/// This can return one of two things: a simple address or a bitfield
154/// reference.  In either case, the LLVM Value* in the LValue structure is
155/// guaranteed to be an LLVM pointer type.
156///
157/// If this returns a bitfield reference, nothing about the pointee type of
158/// the LLVM value is known: For example, it may not be a pointer to an
159/// integer.
160///
161/// If this returns a normal address, and if the lvalue's C type is fixed
162/// size, this method guarantees that the returned pointer type will point to
163/// an LLVM type of the same size of the lvalue's type.  If the lvalue has a
164/// variable length type, this is not possible.
165///
166LValue CodeGenFunction::EmitLValue(const Expr *E) {
167  switch (E->getStmtClass()) {
168  default: return EmitUnsupportedLValue(E, "l-value expression");
169
170  case Expr::BinaryOperatorClass:
171    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
172  case Expr::CallExprClass:
173  case Expr::CXXOperatorCallExprClass:
174    return EmitCallExprLValue(cast<CallExpr>(E));
175  case Expr::VAArgExprClass:
176    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
177  case Expr::DeclRefExprClass:
178  case Expr::QualifiedDeclRefExprClass:
179    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
180  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
181  case Expr::PredefinedExprClass:
182    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
183  case Expr::StringLiteralClass:
184    return EmitStringLiteralLValue(cast<StringLiteral>(E));
185  case Expr::ObjCEncodeExprClass:
186    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
187
188  case Expr::BlockDeclRefExprClass:
189    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
190
191  case Expr::CXXConditionDeclExprClass:
192    return EmitCXXConditionDeclLValue(cast<CXXConditionDeclExpr>(E));
193  case Expr::CXXTemporaryObjectExprClass:
194  case Expr::CXXConstructExprClass:
195    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
196  case Expr::CXXBindTemporaryExprClass:
197    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
198
199  case Expr::ObjCMessageExprClass:
200    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
201  case Expr::ObjCIvarRefExprClass:
202    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
203  case Expr::ObjCPropertyRefExprClass:
204    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
205  case Expr::ObjCKVCRefExprClass:
206    return EmitObjCKVCRefLValue(cast<ObjCKVCRefExpr>(E));
207  case Expr::ObjCSuperExprClass:
208    return EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
209
210  case Expr::StmtExprClass:
211    return EmitStmtExprLValue(cast<StmtExpr>(E));
212  case Expr::UnaryOperatorClass:
213    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
214  case Expr::ArraySubscriptExprClass:
215    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
216  case Expr::ExtVectorElementExprClass:
217    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
218  case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
219  case Expr::CompoundLiteralExprClass:
220    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
221  case Expr::ConditionalOperatorClass:
222    return EmitConditionalOperator(cast<ConditionalOperator>(E));
223  case Expr::ChooseExprClass:
224    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
225  case Expr::ImplicitCastExprClass:
226  case Expr::CStyleCastExprClass:
227  case Expr::CXXFunctionalCastExprClass:
228  case Expr::CXXStaticCastExprClass:
229  case Expr::CXXDynamicCastExprClass:
230  case Expr::CXXReinterpretCastExprClass:
231  case Expr::CXXConstCastExprClass:
232    return EmitCastLValue(cast<CastExpr>(E));
233  }
234}
235
236llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
237                                               QualType Ty) {
238  llvm::Value *V = Builder.CreateLoad(Addr, Volatile, "tmp");
239
240  // Bool can have different representation in memory than in registers.
241  if (Ty->isBooleanType())
242    if (V->getType() != llvm::Type::Int1Ty)
243      V = Builder.CreateTrunc(V, llvm::Type::Int1Ty, "tobool");
244
245  return V;
246}
247
248void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
249                                        bool Volatile, QualType Ty) {
250
251  if (Ty->isBooleanType()) {
252    // Bool can have different representation in memory than in registers.
253    const llvm::Type *SrcTy = Value->getType();
254    const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
255    if (DstPtr->getElementType() != SrcTy) {
256      const llvm::Type *MemTy =
257        VMContext.getPointerType(SrcTy, DstPtr->getAddressSpace());
258      Addr = Builder.CreateBitCast(Addr, MemTy, "storetmp");
259    }
260  }
261  Builder.CreateStore(Value, Addr, Volatile);
262}
263
264/// EmitLoadOfLValue - Given an expression that represents a value lvalue,
265/// this method emits the address of the lvalue, then loads the result as an
266/// rvalue, returning the rvalue.
267RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
268  if (LV.isObjCWeak()) {
269    // load of a __weak object.
270    llvm::Value *AddrWeakObj = LV.getAddress();
271    llvm::Value *read_weak = CGM.getObjCRuntime().EmitObjCWeakRead(*this,
272                                                                   AddrWeakObj);
273    return RValue::get(read_weak);
274  }
275
276  if (LV.isSimple()) {
277    llvm::Value *Ptr = LV.getAddress();
278    const llvm::Type *EltTy =
279      cast<llvm::PointerType>(Ptr->getType())->getElementType();
280
281    // Simple scalar l-value.
282    if (EltTy->isSingleValueType())
283      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
284                                          ExprType));
285
286    assert(ExprType->isFunctionType() && "Unknown scalar value");
287    return RValue::get(Ptr);
288  }
289
290  if (LV.isVectorElt()) {
291    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
292                                          LV.isVolatileQualified(), "tmp");
293    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
294                                                    "vecext"));
295  }
296
297  // If this is a reference to a subset of the elements of a vector, either
298  // shuffle the input or extract/insert them as appropriate.
299  if (LV.isExtVectorElt())
300    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
301
302  if (LV.isBitfield())
303    return EmitLoadOfBitfieldLValue(LV, ExprType);
304
305  if (LV.isPropertyRef())
306    return EmitLoadOfPropertyRefLValue(LV, ExprType);
307
308  assert(LV.isKVCRef() && "Unknown LValue type!");
309  return EmitLoadOfKVCRefLValue(LV, ExprType);
310}
311
312RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
313                                                 QualType ExprType) {
314  unsigned StartBit = LV.getBitfieldStartBit();
315  unsigned BitfieldSize = LV.getBitfieldSize();
316  llvm::Value *Ptr = LV.getBitfieldAddr();
317
318  const llvm::Type *EltTy =
319    cast<llvm::PointerType>(Ptr->getType())->getElementType();
320  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
321
322  // In some cases the bitfield may straddle two memory locations.
323  // Currently we load the entire bitfield, then do the magic to
324  // sign-extend it if necessary. This results in somewhat more code
325  // than necessary for the common case (one load), since two shifts
326  // accomplish both the masking and sign extension.
327  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
328  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
329
330  // Shift to proper location.
331  if (StartBit)
332    Val = Builder.CreateLShr(Val, llvm::ConstantInt::get(EltTy, StartBit),
333                             "bf.lo");
334
335  // Mask off unused bits.
336  llvm::Constant *LowMask = llvm::ConstantInt::get(VMContext,
337                                llvm::APInt::getLowBitsSet(EltTySize, LowBits));
338  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
339
340  // Fetch the high bits if necessary.
341  if (LowBits < BitfieldSize) {
342    unsigned HighBits = BitfieldSize - LowBits;
343    llvm::Value *HighPtr =
344      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
345                        "bf.ptr.hi");
346    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
347                                              LV.isVolatileQualified(),
348                                              "tmp");
349
350    // Mask off unused bits.
351    llvm::Constant *HighMask = llvm::ConstantInt::get(VMContext,
352                               llvm::APInt::getLowBitsSet(EltTySize, HighBits));
353    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
354
355    // Shift to proper location and or in to bitfield value.
356    HighVal = Builder.CreateShl(HighVal,
357                                llvm::ConstantInt::get(EltTy, LowBits));
358    Val = Builder.CreateOr(Val, HighVal, "bf.val");
359  }
360
361  // Sign extend if necessary.
362  if (LV.isBitfieldSigned()) {
363    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
364                                                    EltTySize - BitfieldSize);
365    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
366                             ExtraBits, "bf.val.sext");
367  }
368
369  // The bitfield type and the normal type differ when the storage sizes
370  // differ (currently just _Bool).
371  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
372
373  return RValue::get(Val);
374}
375
376RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
377                                                    QualType ExprType) {
378  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
379}
380
381RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
382                                               QualType ExprType) {
383  return EmitObjCPropertyGet(LV.getKVCRefExpr());
384}
385
386// If this is a reference to a subset of the elements of a vector, create an
387// appropriate shufflevector.
388RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
389                                                         QualType ExprType) {
390  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
391                                        LV.isVolatileQualified(), "tmp");
392
393  const llvm::Constant *Elts = LV.getExtVectorElts();
394
395  // If the result of the expression is a non-vector type, we must be
396  // extracting a single element.  Just codegen as an extractelement.
397  const VectorType *ExprVT = ExprType->getAsVectorType();
398  if (!ExprVT) {
399    unsigned InIdx = getAccessedFieldNo(0, Elts);
400    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
401    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
402  }
403
404  // Always use shuffle vector to try to retain the original program structure
405  unsigned NumResultElts = ExprVT->getNumElements();
406
407  llvm::SmallVector<llvm::Constant*, 4> Mask;
408  for (unsigned i = 0; i != NumResultElts; ++i) {
409    unsigned InIdx = getAccessedFieldNo(i, Elts);
410    Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
411  }
412
413  llvm::Value *MaskV = VMContext.getConstantVector(&Mask[0], Mask.size());
414  Vec = Builder.CreateShuffleVector(Vec,
415                                    VMContext.getUndef(Vec->getType()),
416                                    MaskV, "tmp");
417  return RValue::get(Vec);
418}
419
420
421
422/// EmitStoreThroughLValue - Store the specified rvalue into the specified
423/// lvalue, where both are guaranteed to the have the same type, and that type
424/// is 'Ty'.
425void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
426                                             QualType Ty) {
427  if (!Dst.isSimple()) {
428    if (Dst.isVectorElt()) {
429      // Read/modify/write the vector, inserting the new element.
430      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
431                                            Dst.isVolatileQualified(), "tmp");
432      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
433                                        Dst.getVectorIdx(), "vecins");
434      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
435      return;
436    }
437
438    // If this is an update of extended vector elements, insert them as
439    // appropriate.
440    if (Dst.isExtVectorElt())
441      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
442
443    if (Dst.isBitfield())
444      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
445
446    if (Dst.isPropertyRef())
447      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
448
449    if (Dst.isKVCRef())
450      return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
451
452    assert(0 && "Unknown LValue type");
453  }
454
455  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
456    // load of a __weak object.
457    llvm::Value *LvalueDst = Dst.getAddress();
458    llvm::Value *src = Src.getScalarVal();
459     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
460    return;
461  }
462
463  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
464    // load of a __strong object.
465    llvm::Value *LvalueDst = Dst.getAddress();
466    llvm::Value *src = Src.getScalarVal();
467#if 0
468    // FIXME. We cannot positively determine if we have an 'ivar' assignment,
469    // object assignment or an unknown assignment. For now, generate call to
470    // objc_assign_strongCast assignment which is a safe, but consevative
471    // assumption.
472    if (Dst.isObjCIvar())
473      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, LvalueDst);
474    else
475      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
476#endif
477    if (Dst.isGlobalObjCRef())
478      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
479    else
480      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
481    return;
482  }
483
484  assert(Src.isScalar() && "Can't emit an agg store with this method");
485  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
486                    Dst.isVolatileQualified(), Ty);
487}
488
489void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
490                                                     QualType Ty,
491                                                     llvm::Value **Result) {
492  unsigned StartBit = Dst.getBitfieldStartBit();
493  unsigned BitfieldSize = Dst.getBitfieldSize();
494  llvm::Value *Ptr = Dst.getBitfieldAddr();
495
496  const llvm::Type *EltTy =
497    cast<llvm::PointerType>(Ptr->getType())->getElementType();
498  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
499
500  // Get the new value, cast to the appropriate type and masked to
501  // exactly the size of the bit-field.
502  llvm::Value *SrcVal = Src.getScalarVal();
503  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
504  llvm::Constant *Mask = llvm::ConstantInt::get(VMContext,
505                           llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
506  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
507
508  // Return the new value of the bit-field, if requested.
509  if (Result) {
510    // Cast back to the proper type for result.
511    const llvm::Type *SrcTy = SrcVal->getType();
512    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
513                                                  "bf.reload.val");
514
515    // Sign extend if necessary.
516    if (Dst.isBitfieldSigned()) {
517      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
518      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
519                                                      SrcTySize - BitfieldSize);
520      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
521                                    ExtraBits, "bf.reload.sext");
522    }
523
524    *Result = SrcTrunc;
525  }
526
527  // In some cases the bitfield may straddle two memory locations.
528  // Emit the low part first and check to see if the high needs to be
529  // done.
530  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
531  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
532                                           "bf.prev.low");
533
534  // Compute the mask for zero-ing the low part of this bitfield.
535  llvm::Constant *InvMask =
536    llvm::ConstantInt::get(VMContext,
537             ~llvm::APInt::getBitsSet(EltTySize, StartBit, StartBit + LowBits));
538
539  // Compute the new low part as
540  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
541  // with the shift of NewVal implicitly stripping the high bits.
542  llvm::Value *NewLowVal =
543    Builder.CreateShl(NewVal, llvm::ConstantInt::get(EltTy, StartBit),
544                      "bf.value.lo");
545  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
546  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
547
548  // Write back.
549  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
550
551  // If the low part doesn't cover the bitfield emit a high part.
552  if (LowBits < BitfieldSize) {
553    unsigned HighBits = BitfieldSize - LowBits;
554    llvm::Value *HighPtr =
555      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
556                        "bf.ptr.hi");
557    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
558                                              Dst.isVolatileQualified(),
559                                              "bf.prev.hi");
560
561    // Compute the mask for zero-ing the high part of this bitfield.
562    llvm::Constant *InvMask =
563      llvm::ConstantInt::get(VMContext, ~llvm::APInt::getLowBitsSet(EltTySize,
564                               HighBits));
565
566    // Compute the new high part as
567    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
568    // where the high bits of NewVal have already been cleared and the
569    // shift stripping the low bits.
570    llvm::Value *NewHighVal =
571      Builder.CreateLShr(NewVal, llvm::ConstantInt::get(EltTy, LowBits),
572                        "bf.value.high");
573    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
574    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
575
576    // Write back.
577    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
578  }
579}
580
581void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
582                                                        LValue Dst,
583                                                        QualType Ty) {
584  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
585}
586
587void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
588                                                   LValue Dst,
589                                                   QualType Ty) {
590  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
591}
592
593void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
594                                                               LValue Dst,
595                                                               QualType Ty) {
596  // This access turns into a read/modify/write of the vector.  Load the input
597  // value now.
598  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
599                                        Dst.isVolatileQualified(), "tmp");
600  const llvm::Constant *Elts = Dst.getExtVectorElts();
601
602  llvm::Value *SrcVal = Src.getScalarVal();
603
604  if (const VectorType *VTy = Ty->getAsVectorType()) {
605    unsigned NumSrcElts = VTy->getNumElements();
606    unsigned NumDstElts =
607       cast<llvm::VectorType>(Vec->getType())->getNumElements();
608    if (NumDstElts == NumSrcElts) {
609      // Use shuffle vector is the src and destination are the same number
610      // of elements and restore the vector mask since it is on the side
611      // it will be stored.
612      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
613      for (unsigned i = 0; i != NumSrcElts; ++i) {
614        unsigned InIdx = getAccessedFieldNo(i, Elts);
615        Mask[InIdx] = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
616      }
617
618      llvm::Value *MaskV = VMContext.getConstantVector(&Mask[0], Mask.size());
619      Vec = Builder.CreateShuffleVector(SrcVal,
620                                        VMContext.getUndef(Vec->getType()),
621                                        MaskV, "tmp");
622    }
623    else if (NumDstElts > NumSrcElts) {
624      // Extended the source vector to the same length and then shuffle it
625      // into the destination.
626      // FIXME: since we're shuffling with undef, can we just use the indices
627      //        into that?  This could be simpler.
628      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
629      unsigned i;
630      for (i = 0; i != NumSrcElts; ++i)
631        ExtMask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
632      for (; i != NumDstElts; ++i)
633        ExtMask.push_back(VMContext.getUndef(llvm::Type::Int32Ty));
634      llvm::Value *ExtMaskV = VMContext.getConstantVector(&ExtMask[0],
635                                                        ExtMask.size());
636      llvm::Value *ExtSrcVal =
637        Builder.CreateShuffleVector(SrcVal,
638                                    VMContext.getUndef(SrcVal->getType()),
639                                    ExtMaskV, "tmp");
640      // build identity
641      llvm::SmallVector<llvm::Constant*, 4> Mask;
642      for (unsigned i = 0; i != NumDstElts; ++i) {
643        Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
644      }
645      // modify when what gets shuffled in
646      for (unsigned i = 0; i != NumSrcElts; ++i) {
647        unsigned Idx = getAccessedFieldNo(i, Elts);
648        Mask[Idx] = llvm::ConstantInt::get(llvm::Type::Int32Ty, i+NumDstElts);
649      }
650      llvm::Value *MaskV = VMContext.getConstantVector(&Mask[0], Mask.size());
651      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
652    }
653    else {
654      // We should never shorten the vector
655      assert(0 && "unexpected shorten vector length");
656    }
657  } else {
658    // If the Src is a scalar (not a vector) it must be updating one element.
659    unsigned InIdx = getAccessedFieldNo(0, Elts);
660    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
661    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
662  }
663
664  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
665}
666
667LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
668  const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
669
670  if (VD && (VD->isBlockVarDecl() || isa<ParmVarDecl>(VD) ||
671        isa<ImplicitParamDecl>(VD))) {
672    LValue LV;
673    bool NonGCable = VD->hasLocalStorage() &&
674      !VD->hasAttr<BlocksAttr>();
675    if (VD->hasExternalStorage()) {
676      llvm::Value *V = CGM.GetAddrOfGlobalVar(VD);
677      if (VD->getType()->isReferenceType())
678        V = Builder.CreateLoad(V, "tmp");
679      LV = LValue::MakeAddr(V, E->getType().getCVRQualifiers(),
680                            getContext().getObjCGCAttrKind(E->getType()),
681                            E->getType().getAddressSpace());
682    }
683    else {
684      llvm::Value *V = LocalDeclMap[VD];
685      assert(V && "DeclRefExpr not entered in LocalDeclMap?");
686      // local variables do not get their gc attribute set.
687      QualType::GCAttrTypes attr = QualType::GCNone;
688      // local static?
689      if (!NonGCable)
690        attr = getContext().getObjCGCAttrKind(E->getType());
691      if (VD->hasAttr<BlocksAttr>()) {
692        bool needsCopyDispose = BlockRequiresCopying(VD->getType());
693        const llvm::Type *PtrStructTy = V->getType();
694        const llvm::Type *Ty = PtrStructTy;
695        Ty = VMContext.getPointerType(Ty, 0);
696        V = Builder.CreateStructGEP(V, 1, "forwarding");
697        V = Builder.CreateBitCast(V, Ty);
698        V = Builder.CreateLoad(V, false);
699        V = Builder.CreateBitCast(V, PtrStructTy);
700        V = Builder.CreateStructGEP(V, needsCopyDispose*2 + 4, "x");
701      }
702      if (VD->getType()->isReferenceType())
703        V = Builder.CreateLoad(V, "tmp");
704      LV = LValue::MakeAddr(V, E->getType().getCVRQualifiers(), attr,
705                            E->getType().getAddressSpace());
706    }
707    LValue::SetObjCNonGC(LV, NonGCable);
708    return LV;
709  } else if (VD && VD->isFileVarDecl()) {
710    llvm::Value *V = CGM.GetAddrOfGlobalVar(VD);
711    if (VD->getType()->isReferenceType())
712      V = Builder.CreateLoad(V, "tmp");
713    LValue LV = LValue::MakeAddr(V, E->getType().getCVRQualifiers(),
714                                 getContext().getObjCGCAttrKind(E->getType()),
715                                 E->getType().getAddressSpace());
716    if (LV.isObjCStrong())
717      LV.SetGlobalObjCRef(LV, true);
718    return LV;
719  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) {
720    llvm::Value* V = CGM.GetAddrOfFunction(GlobalDecl(FD));
721    if (!FD->hasPrototype()) {
722      if (const FunctionProtoType *Proto =
723              FD->getType()->getAsFunctionProtoType()) {
724        // Ugly case: for a K&R-style definition, the type of the definition
725        // isn't the same as the type of a use.  Correct for this with a
726        // bitcast.
727        QualType NoProtoType =
728            getContext().getFunctionNoProtoType(Proto->getResultType());
729        NoProtoType = getContext().getPointerType(NoProtoType);
730        V = Builder.CreateBitCast(V, ConvertType(NoProtoType), "tmp");
731      }
732    }
733    return LValue::MakeAddr(V, E->getType().getCVRQualifiers(),
734                            getContext().getObjCGCAttrKind(E->getType()),
735                            E->getType().getAddressSpace());
736  }
737  else if (const ImplicitParamDecl *IPD =
738      dyn_cast<ImplicitParamDecl>(E->getDecl())) {
739    llvm::Value *V = LocalDeclMap[IPD];
740    assert(V && "BlockVarDecl not entered in LocalDeclMap?");
741    return LValue::MakeAddr(V, E->getType().getCVRQualifiers(),
742                            getContext().getObjCGCAttrKind(E->getType()),
743                            E->getType().getAddressSpace());
744  }
745  assert(0 && "Unimp declref");
746  //an invalid LValue, but the assert will
747  //ensure that this point is never reached.
748  return LValue();
749}
750
751LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
752  return LValue::MakeAddr(GetAddrOfBlockDecl(E),
753                          E->getType().getCVRQualifiers(),
754                          getContext().getObjCGCAttrKind(E->getType()),
755                          E->getType().getAddressSpace());
756}
757
758LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
759  // __extension__ doesn't affect lvalue-ness.
760  if (E->getOpcode() == UnaryOperator::Extension)
761    return EmitLValue(E->getSubExpr());
762
763  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
764  switch (E->getOpcode()) {
765  default: assert(0 && "Unknown unary operator lvalue!");
766  case UnaryOperator::Deref:
767    {
768      QualType T = E->getSubExpr()->getType()->getPointeeType();
769      assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
770
771      LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()),
772                                   T.getCVRQualifiers(),
773                                   getContext().getObjCGCAttrKind(T),
774                                   ExprTy.getAddressSpace());
775     // We should not generate __weak write barrier on indirect reference
776     // of a pointer to object; as in void foo (__weak id *param); *param = 0;
777     // But, we continue to generate __strong write barrier on indirect write
778     // into a pointer to object.
779     if (getContext().getLangOptions().ObjC1 &&
780         getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
781         LV.isObjCWeak())
782       LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
783     return LV;
784    }
785  case UnaryOperator::Real:
786  case UnaryOperator::Imag:
787    LValue LV = EmitLValue(E->getSubExpr());
788    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
789    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
790                                                    Idx, "idx"),
791                            ExprTy.getCVRQualifiers(),
792                            QualType::GCNone,
793                            ExprTy.getAddressSpace());
794  }
795}
796
797LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
798  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E), 0);
799}
800
801LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
802  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E), 0);
803}
804
805
806LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
807  std::string GlobalVarName;
808
809  switch (Type) {
810  default:
811    assert(0 && "Invalid type");
812  case PredefinedExpr::Func:
813    GlobalVarName = "__func__.";
814    break;
815  case PredefinedExpr::Function:
816    GlobalVarName = "__FUNCTION__.";
817    break;
818  case PredefinedExpr::PrettyFunction:
819    // FIXME:: Demangle C++ method names
820    GlobalVarName = "__PRETTY_FUNCTION__.";
821    break;
822  }
823
824  // FIXME: This isn't right at all.  The logic for computing this should go
825  // into a method on PredefinedExpr.  This would allow sema and codegen to be
826  // consistent for things like sizeof(__func__) etc.
827  std::string FunctionName;
828  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurCodeDecl)) {
829    FunctionName = CGM.getMangledName(FD);
830  } else {
831    // Just get the mangled name; skipping the asm prefix if it
832    // exists.
833    FunctionName = CurFn->getName();
834    if (FunctionName[0] == '\01')
835      FunctionName = FunctionName.substr(1, std::string::npos);
836  }
837
838  GlobalVarName += FunctionName;
839  llvm::Constant *C =
840    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
841  return LValue::MakeAddr(C, 0);
842}
843
844LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
845  switch (E->getIdentType()) {
846  default:
847    return EmitUnsupportedLValue(E, "predefined expression");
848  case PredefinedExpr::Func:
849  case PredefinedExpr::Function:
850  case PredefinedExpr::PrettyFunction:
851    return EmitPredefinedFunctionName(E->getIdentType());
852  }
853}
854
855LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
856  // The index must always be an integer, which is not an aggregate.  Emit it.
857  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
858  QualType IdxTy  = E->getIdx()->getType();
859  bool IdxSigned = IdxTy->isSignedIntegerType();
860
861  // If the base is a vector type, then we are forming a vector element lvalue
862  // with this subscript.
863  if (E->getBase()->getType()->isVectorType()) {
864    // Emit the vector as an lvalue to get its address.
865    LValue LHS = EmitLValue(E->getBase());
866    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
867    Idx = Builder.CreateIntCast(Idx, llvm::Type::Int32Ty, IdxSigned, "vidx");
868    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
869      E->getBase()->getType().getCVRQualifiers());
870  }
871
872  // The base must be a pointer, which is not an aggregate.  Emit it.
873  llvm::Value *Base = EmitScalarExpr(E->getBase());
874
875  // Extend or truncate the index type to 32 or 64-bits.
876  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
877  if (IdxBitwidth != LLVMPointerWidth)
878    Idx = Builder.CreateIntCast(Idx, VMContext.getIntegerType(LLVMPointerWidth),
879                                IdxSigned, "idxprom");
880
881  // We know that the pointer points to a type of the correct size,
882  // unless the size is a VLA or Objective-C interface.
883  llvm::Value *Address = 0;
884  if (const VariableArrayType *VAT =
885        getContext().getAsVariableArrayType(E->getType())) {
886    llvm::Value *VLASize = VLASizeMap[VAT];
887
888    Idx = Builder.CreateMul(Idx, VLASize);
889
890    QualType BaseType = getContext().getBaseElementType(VAT);
891
892    uint64_t BaseTypeSize = getContext().getTypeSize(BaseType) / 8;
893    Idx = Builder.CreateUDiv(Idx,
894                             llvm::ConstantInt::get(Idx->getType(),
895                                                    BaseTypeSize));
896    Address = Builder.CreateGEP(Base, Idx, "arrayidx");
897  } else if (const ObjCInterfaceType *OIT =
898             dyn_cast<ObjCInterfaceType>(E->getType())) {
899    llvm::Value *InterfaceSize =
900      llvm::ConstantInt::get(Idx->getType(),
901                             getContext().getTypeSize(OIT) / 8);
902
903    Idx = Builder.CreateMul(Idx, InterfaceSize);
904
905    llvm::Type *i8PTy = VMContext.getPointerTypeUnqual(llvm::Type::Int8Ty);
906    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
907                                Idx, "arrayidx");
908    Address = Builder.CreateBitCast(Address, Base->getType());
909  } else {
910    Address = Builder.CreateGEP(Base, Idx, "arrayidx");
911  }
912
913  QualType T = E->getBase()->getType()->getPointeeType();
914  assert(!T.isNull() &&
915         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
916
917  LValue LV = LValue::MakeAddr(Address,
918                               T.getCVRQualifiers(),
919                               getContext().getObjCGCAttrKind(T),
920                               E->getBase()->getType().getAddressSpace());
921  if (getContext().getLangOptions().ObjC1 &&
922      getContext().getLangOptions().getGCMode() != LangOptions::NonGC)
923    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
924  return LV;
925}
926
927static
928llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
929                                       llvm::SmallVector<unsigned, 4> &Elts) {
930  llvm::SmallVector<llvm::Constant *, 4> CElts;
931
932  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
933    CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, Elts[i]));
934
935  return VMContext.getConstantVector(&CElts[0], CElts.size());
936}
937
938LValue CodeGenFunction::
939EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
940  // Emit the base vector as an l-value.
941  LValue Base;
942
943  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
944  if (!E->isArrow()) {
945    assert(E->getBase()->getType()->isVectorType());
946    Base = EmitLValue(E->getBase());
947  } else {
948    const PointerType *PT = E->getBase()->getType()->getAsPointerType();
949    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
950    Base = LValue::MakeAddr(Ptr, PT->getPointeeType().getCVRQualifiers(),
951                            QualType::GCNone,
952                            PT->getPointeeType().getAddressSpace());
953  }
954
955  // Encode the element access list into a vector of unsigned indices.
956  llvm::SmallVector<unsigned, 4> Indices;
957  E->getEncodedElementAccess(Indices);
958
959  if (Base.isSimple()) {
960    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
961    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
962                                    Base.getQualifiers());
963  }
964  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
965
966  llvm::Constant *BaseElts = Base.getExtVectorElts();
967  llvm::SmallVector<llvm::Constant *, 4> CElts;
968
969  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
970    if (isa<llvm::ConstantAggregateZero>(BaseElts))
971      CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
972    else
973      CElts.push_back(BaseElts->getOperand(Indices[i]));
974  }
975  llvm::Constant *CV = VMContext.getConstantVector(&CElts[0], CElts.size());
976  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
977                                  Base.getQualifiers());
978}
979
980LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
981  bool isUnion = false;
982  bool isIvar = false;
983  bool isNonGC = false;
984  Expr *BaseExpr = E->getBase();
985  llvm::Value *BaseValue = NULL;
986  unsigned CVRQualifiers=0;
987
988  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
989  if (E->isArrow()) {
990    BaseValue = EmitScalarExpr(BaseExpr);
991    const PointerType *PTy =
992      BaseExpr->getType()->getAsPointerType();
993    if (PTy->getPointeeType()->isUnionType())
994      isUnion = true;
995    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
996    QualType ClassTy = BaseExpr->getType();
997    ClassTy = ClassTy->getPointeeType();
998    if (CXXRecordDecl *ClassDecl =
999        dyn_cast<CXXRecordDecl>(ClassTy->getAsRecordType()->getDecl())) {
1000      FieldDecl *Field = dyn_cast<FieldDecl>(E->getMemberDecl());
1001      if (CXXRecordDecl *BaseClassDecl =
1002          dyn_cast<CXXRecordDecl>(Field->getDeclContext()))
1003        BaseValue = AddressCXXOfBaseClass(BaseValue, ClassDecl, BaseClassDecl);
1004    }
1005  } else if (isa<ObjCPropertyRefExpr>(BaseExpr) ||
1006             isa<ObjCKVCRefExpr>(BaseExpr)) {
1007    RValue RV = EmitObjCPropertyGet(BaseExpr);
1008    BaseValue = RV.getAggregateAddr();
1009    if (BaseExpr->getType()->isUnionType())
1010      isUnion = true;
1011    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
1012  } else {
1013    LValue BaseLV = EmitLValue(BaseExpr);
1014    if (BaseLV.isObjCIvar())
1015      isIvar = true;
1016    if (BaseLV.isNonGC())
1017      isNonGC = true;
1018    // FIXME: this isn't right for bitfields.
1019    BaseValue = BaseLV.getAddress();
1020    if (BaseExpr->getType()->isUnionType())
1021      isUnion = true;
1022    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
1023    if (CXXRecordDecl *ClassDecl =
1024          dyn_cast<CXXRecordDecl>(
1025                        BaseExpr->getType()->getAsRecordType()->getDecl())) {
1026        FieldDecl *Field = dyn_cast<FieldDecl>(E->getMemberDecl());
1027        if (CXXRecordDecl *BaseClassDecl =
1028            dyn_cast<CXXRecordDecl>(Field->getDeclContext()))
1029            BaseValue =
1030              AddressCXXOfBaseClass(BaseValue, ClassDecl, BaseClassDecl);
1031    }
1032  }
1033
1034  FieldDecl *Field = dyn_cast<FieldDecl>(E->getMemberDecl());
1035  // FIXME: Handle non-field member expressions
1036  assert(Field && "No code generation for non-field member references");
1037  LValue MemExpLV = EmitLValueForField(BaseValue, Field, isUnion,
1038                                       CVRQualifiers);
1039  LValue::SetObjCIvar(MemExpLV, isIvar);
1040  LValue::SetObjCNonGC(MemExpLV, isNonGC);
1041  return MemExpLV;
1042}
1043
1044LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
1045                                              FieldDecl* Field,
1046                                              unsigned CVRQualifiers) {
1047  CodeGenTypes::BitFieldInfo Info = CGM.getTypes().getBitFieldInfo(Field);
1048
1049  // FIXME: CodeGenTypes should expose a method to get the appropriate type for
1050  // FieldTy (the appropriate type is ABI-dependent).
1051  const llvm::Type *FieldTy =
1052    CGM.getTypes().ConvertTypeForMem(Field->getType());
1053  const llvm::PointerType *BaseTy =
1054  cast<llvm::PointerType>(BaseValue->getType());
1055  unsigned AS = BaseTy->getAddressSpace();
1056  BaseValue = Builder.CreateBitCast(BaseValue,
1057                                    VMContext.getPointerType(FieldTy, AS),
1058                                    "tmp");
1059
1060  llvm::Value *Idx =
1061    llvm::ConstantInt::get(llvm::Type::Int32Ty, Info.FieldNo);
1062  llvm::Value *V = Builder.CreateGEP(BaseValue, Idx, "tmp");
1063
1064  return LValue::MakeBitfield(V, Info.Start, Info.Size,
1065                              Field->getType()->isSignedIntegerType(),
1066                            Field->getType().getCVRQualifiers()|CVRQualifiers);
1067}
1068
1069LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
1070                                           FieldDecl* Field,
1071                                           bool isUnion,
1072                                           unsigned CVRQualifiers)
1073{
1074  if (Field->isBitField())
1075    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1076
1077  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
1078  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1079
1080  // Match union field type.
1081  if (isUnion) {
1082    const llvm::Type *FieldTy =
1083      CGM.getTypes().ConvertTypeForMem(Field->getType());
1084    const llvm::PointerType * BaseTy =
1085      cast<llvm::PointerType>(BaseValue->getType());
1086    unsigned AS = BaseTy->getAddressSpace();
1087    V = Builder.CreateBitCast(V,
1088                              VMContext.getPointerType(FieldTy, AS),
1089                              "tmp");
1090  }
1091  if (Field->getType()->isReferenceType())
1092    V = Builder.CreateLoad(V, "tmp");
1093
1094  QualType::GCAttrTypes attr = QualType::GCNone;
1095  if (CGM.getLangOptions().ObjC1 &&
1096      CGM.getLangOptions().getGCMode() != LangOptions::NonGC) {
1097    QualType Ty = Field->getType();
1098    attr = Ty.getObjCGCAttr();
1099    if (attr != QualType::GCNone) {
1100      // __weak attribute on a field is ignored.
1101      if (attr == QualType::Weak)
1102        attr = QualType::GCNone;
1103    }
1104    else if (Ty->isObjCObjectPointerType())
1105      attr = QualType::Strong;
1106  }
1107  LValue LV =
1108    LValue::MakeAddr(V,
1109                     Field->getType().getCVRQualifiers()|CVRQualifiers,
1110                     attr,
1111                     Field->getType().getAddressSpace());
1112  return LV;
1113}
1114
1115LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1116  const llvm::Type *LTy = ConvertType(E->getType());
1117  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
1118
1119  const Expr* InitExpr = E->getInitializer();
1120  LValue Result = LValue::MakeAddr(DeclPtr, E->getType().getCVRQualifiers(),
1121                                   QualType::GCNone,
1122                                   E->getType().getAddressSpace());
1123
1124  if (E->getType()->isComplexType()) {
1125    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1126  } else if (hasAggregateLLVMType(E->getType())) {
1127    EmitAnyExpr(InitExpr, DeclPtr, false);
1128  } else {
1129    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1130  }
1131
1132  return Result;
1133}
1134
1135LValue CodeGenFunction::EmitConditionalOperator(const ConditionalOperator* E) {
1136  // We don't handle vectors yet.
1137  if (E->getType()->isVectorType())
1138    return EmitUnsupportedLValue(E, "conditional operator");
1139
1140  // ?: here should be an aggregate.
1141  assert((hasAggregateLLVMType(E->getType()) &&
1142          !E->getType()->isAnyComplexType()) &&
1143         "Unexpected conditional operator!");
1144
1145  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1146  EmitAggExpr(E, Temp, false);
1147
1148  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1149                          getContext().getObjCGCAttrKind(E->getType()),
1150                          E->getType().getAddressSpace());
1151
1152}
1153
1154/// EmitCastLValue - Casts are never lvalues.  If a cast is needed by the code
1155/// generator in an lvalue context, then it must mean that we need the address
1156/// of an aggregate in order to access one of its fields.  This can happen for
1157/// all the reasons that casts are permitted with aggregate result, including
1158/// noop aggregate casts, and cast from scalar to union.
1159LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1160  // If this is an aggregate-to-aggregate cast, just use the input's address as
1161  // the lvalue.
1162  if (getContext().hasSameUnqualifiedType(E->getType(),
1163                                          E->getSubExpr()->getType()))
1164    return EmitLValue(E->getSubExpr());
1165
1166  // Otherwise, we must have a cast from scalar to union.
1167  assert(E->getType()->isUnionType() && "Expected scalar-to-union cast");
1168
1169  // Casts are only lvalues when the source and destination types are the same.
1170  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1171  EmitAnyExpr(E->getSubExpr(), Temp, false);
1172
1173  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1174                          getContext().getObjCGCAttrKind(E->getType()),
1175                          E->getType().getAddressSpace());
1176}
1177
1178//===--------------------------------------------------------------------===//
1179//                             Expression Emission
1180//===--------------------------------------------------------------------===//
1181
1182
1183RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
1184  // Builtins never have block type.
1185  if (E->getCallee()->getType()->isBlockPointerType())
1186    return EmitBlockCallExpr(E);
1187
1188  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1189    return EmitCXXMemberCallExpr(CE);
1190
1191  const Decl *TargetDecl = 0;
1192  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1193    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1194      TargetDecl = DRE->getDecl();
1195      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1196        if (unsigned builtinID = FD->getBuiltinID(getContext()))
1197          return EmitBuiltinExpr(FD, builtinID, E);
1198    }
1199  }
1200
1201  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1202    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1203      return EmitCXXOperatorMemberCallExpr(CE, MD);
1204
1205  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1206  return EmitCall(Callee, E->getCallee()->getType(),
1207                  E->arg_begin(), E->arg_end(), TargetDecl);
1208}
1209
1210LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1211  // Comma expressions just emit their LHS then their RHS as an l-value.
1212  if (E->getOpcode() == BinaryOperator::Comma) {
1213    EmitAnyExpr(E->getLHS());
1214    return EmitLValue(E->getRHS());
1215  }
1216
1217  // Can only get l-value for binary operator expressions which are a
1218  // simple assignment of aggregate type.
1219  if (E->getOpcode() != BinaryOperator::Assign)
1220    return EmitUnsupportedLValue(E, "binary l-value expression");
1221
1222  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1223  EmitAggExpr(E, Temp, false);
1224  // FIXME: Are these qualifiers correct?
1225  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1226                          getContext().getObjCGCAttrKind(E->getType()),
1227                          E->getType().getAddressSpace());
1228}
1229
1230LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1231  RValue RV = EmitCallExpr(E);
1232
1233  if (RV.isScalar()) {
1234    assert(E->getCallReturnType()->isReferenceType() &&
1235           "Can't have a scalar return unless the return type is a "
1236           "reference type!");
1237
1238    return LValue::MakeAddr(RV.getScalarVal(), E->getType().getCVRQualifiers(),
1239                            getContext().getObjCGCAttrKind(E->getType()),
1240                            E->getType().getAddressSpace());
1241  }
1242
1243  return LValue::MakeAddr(RV.getAggregateAddr(),
1244                          E->getType().getCVRQualifiers(),
1245                          getContext().getObjCGCAttrKind(E->getType()),
1246                          E->getType().getAddressSpace());
1247}
1248
1249LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1250  // FIXME: This shouldn't require another copy.
1251  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1252  EmitAggExpr(E, Temp, false);
1253  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1254                          QualType::GCNone, E->getType().getAddressSpace());
1255}
1256
1257LValue
1258CodeGenFunction::EmitCXXConditionDeclLValue(const CXXConditionDeclExpr *E) {
1259  EmitLocalBlockVarDecl(*E->getVarDecl());
1260  return EmitDeclRefLValue(E);
1261}
1262
1263LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1264  llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()), "tmp");
1265  EmitCXXConstructExpr(Temp, E);
1266  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1267                          QualType::GCNone, E->getType().getAddressSpace());
1268}
1269
1270LValue
1271CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1272  LValue LV = EmitLValue(E->getSubExpr());
1273
1274  PushCXXTemporary(E->getTemporary(), LV.getAddress());
1275
1276  return LV;
1277}
1278
1279LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1280  // Can only get l-value for message expression returning aggregate type
1281  RValue RV = EmitObjCMessageExpr(E);
1282  // FIXME: can this be volatile?
1283  return LValue::MakeAddr(RV.getAggregateAddr(),
1284                          E->getType().getCVRQualifiers(),
1285                          getContext().getObjCGCAttrKind(E->getType()),
1286                          E->getType().getAddressSpace());
1287}
1288
1289llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1290                                             const ObjCIvarDecl *Ivar) {
1291  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1292}
1293
1294LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1295                                          llvm::Value *BaseValue,
1296                                          const ObjCIvarDecl *Ivar,
1297                                          unsigned CVRQualifiers) {
1298  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1299                                                   Ivar, CVRQualifiers);
1300}
1301
1302LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1303  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1304  llvm::Value *BaseValue = 0;
1305  const Expr *BaseExpr = E->getBase();
1306  unsigned CVRQualifiers = 0;
1307  QualType ObjectTy;
1308  if (E->isArrow()) {
1309    BaseValue = EmitScalarExpr(BaseExpr);
1310    ObjectTy = BaseExpr->getType()->getPointeeType();
1311    CVRQualifiers = ObjectTy.getCVRQualifiers();
1312  } else {
1313    LValue BaseLV = EmitLValue(BaseExpr);
1314    // FIXME: this isn't right for bitfields.
1315    BaseValue = BaseLV.getAddress();
1316    ObjectTy = BaseExpr->getType();
1317    CVRQualifiers = ObjectTy.getCVRQualifiers();
1318  }
1319
1320  return EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(), CVRQualifiers);
1321}
1322
1323LValue
1324CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1325  // This is a special l-value that just issues sends when we load or
1326  // store through it.
1327  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1328}
1329
1330LValue
1331CodeGenFunction::EmitObjCKVCRefLValue(const ObjCKVCRefExpr *E) {
1332  // This is a special l-value that just issues sends when we load or
1333  // store through it.
1334  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1335}
1336
1337LValue
1338CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1339  return EmitUnsupportedLValue(E, "use of super");
1340}
1341
1342LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1343
1344  // Can only get l-value for message expression returning aggregate type
1345  RValue RV = EmitAnyExprToTemp(E);
1346  // FIXME: can this be volatile?
1347  return LValue::MakeAddr(RV.getAggregateAddr(),
1348                          E->getType().getCVRQualifiers(),
1349                          getContext().getObjCGCAttrKind(E->getType()),
1350                          E->getType().getAddressSpace());
1351}
1352
1353
1354RValue CodeGenFunction::EmitCall(llvm::Value *Callee, QualType CalleeType,
1355                                 CallExpr::const_arg_iterator ArgBeg,
1356                                 CallExpr::const_arg_iterator ArgEnd,
1357                                 const Decl *TargetDecl) {
1358  // Get the actual function type. The callee type will always be a
1359  // pointer to function type or a block pointer type.
1360  assert(CalleeType->isFunctionPointerType() &&
1361         "Call must have function pointer type!");
1362
1363  QualType FnType = CalleeType->getAsPointerType()->getPointeeType();
1364  QualType ResultType = FnType->getAsFunctionType()->getResultType();
1365
1366  CallArgList Args;
1367  EmitCallArgs(Args, FnType->getAsFunctionProtoType(), ArgBeg, ArgEnd);
1368
1369  return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args),
1370                  Callee, Args, TargetDecl);
1371}
1372