CGExpr.cpp revision b4aa4664ec851573624a7a29c6c750fc1d5cc268 
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 EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
172
173  case Expr::StmtExprClass:
174    return EmitStmtExprLValue(cast<StmtExpr>(E));
175  case Expr::UnaryOperatorClass:
176    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
177  case Expr::ArraySubscriptExprClass:
178    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
179  case Expr::ExtVectorElementExprClass:
180    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
181  case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
182  case Expr::CompoundLiteralExprClass:
183    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
184  case Expr::ConditionalOperatorClass:
185    return EmitConditionalOperator(cast<ConditionalOperator>(E));
186  case Expr::ChooseExprClass:
187    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
188  case Expr::ImplicitCastExprClass:
189  case Expr::CStyleCastExprClass:
190  case Expr::CXXFunctionalCastExprClass:
191  case Expr::CXXStaticCastExprClass:
192  case Expr::CXXDynamicCastExprClass:
193  case Expr::CXXReinterpretCastExprClass:
194  case Expr::CXXConstCastExprClass:
195    return EmitCastLValue(cast<CastExpr>(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, QualType Ty) {
214  // Handle stores of types which have different representations in memory and
215  // as LLVM values.
216
217  // FIXME: We shouldn't be this loose, we should only do this conversion when
218  // we have a type we know has a different memory representation (e.g., bool).
219
220  const llvm::Type *SrcTy = Value->getType();
221  const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
222  if (DstPtr->getElementType() != SrcTy) {
223    const llvm::Type *MemTy =
224      llvm::PointerType::get(SrcTy, DstPtr->getAddressSpace());
225    Addr = Builder.CreateBitCast(Addr, MemTy, "storetmp");
226  }
227
228  Builder.CreateStore(Value, Addr, Volatile);
229}
230
231/// EmitLoadOfLValue - Given an expression that represents a value lvalue,
232/// this method emits the address of the lvalue, then loads the result as an
233/// rvalue, returning the rvalue.
234RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
235  if (LV.isObjCWeak()) {
236    // load of a __weak object.
237    llvm::Value *AddrWeakObj = LV.getAddress();
238    llvm::Value *read_weak = CGM.getObjCRuntime().EmitObjCWeakRead(*this,
239                                                                   AddrWeakObj);
240    return RValue::get(read_weak);
241  }
242
243  if (LV.isSimple()) {
244    llvm::Value *Ptr = LV.getAddress();
245    const llvm::Type *EltTy =
246      cast<llvm::PointerType>(Ptr->getType())->getElementType();
247
248    // Simple scalar l-value.
249    if (EltTy->isSingleValueType())
250      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
251                                          ExprType));
252
253    assert(ExprType->isFunctionType() && "Unknown scalar value");
254    return RValue::get(Ptr);
255  }
256
257  if (LV.isVectorElt()) {
258    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
259                                          LV.isVolatileQualified(), "tmp");
260    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
261                                                    "vecext"));
262  }
263
264  // If this is a reference to a subset of the elements of a vector, either
265  // shuffle the input or extract/insert them as appropriate.
266  if (LV.isExtVectorElt())
267    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
268
269  if (LV.isBitfield())
270    return EmitLoadOfBitfieldLValue(LV, ExprType);
271
272  if (LV.isPropertyRef())
273    return EmitLoadOfPropertyRefLValue(LV, ExprType);
274
275  assert(LV.isKVCRef() && "Unknown LValue type!");
276  return EmitLoadOfKVCRefLValue(LV, ExprType);
277}
278
279RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
280                                                 QualType ExprType) {
281  unsigned StartBit = LV.getBitfieldStartBit();
282  unsigned BitfieldSize = LV.getBitfieldSize();
283  llvm::Value *Ptr = LV.getBitfieldAddr();
284
285  const llvm::Type *EltTy =
286    cast<llvm::PointerType>(Ptr->getType())->getElementType();
287  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
288
289  // In some cases the bitfield may straddle two memory locations.
290  // Currently we load the entire bitfield, then do the magic to
291  // sign-extend it if necessary. This results in somewhat more code
292  // than necessary for the common case (one load), since two shifts
293  // accomplish both the masking and sign extension.
294  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
295  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
296
297  // Shift to proper location.
298  if (StartBit)
299    Val = Builder.CreateLShr(Val, llvm::ConstantInt::get(EltTy, StartBit),
300                             "bf.lo");
301
302  // Mask off unused bits.
303  llvm::Constant *LowMask =
304    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, LowBits));
305  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
306
307  // Fetch the high bits if necessary.
308  if (LowBits < BitfieldSize) {
309    unsigned HighBits = BitfieldSize - LowBits;
310    llvm::Value *HighPtr =
311      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
312                        "bf.ptr.hi");
313    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
314                                              LV.isVolatileQualified(),
315                                              "tmp");
316
317    // Mask off unused bits.
318    llvm::Constant *HighMask =
319      llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, HighBits));
320    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
321
322    // Shift to proper location and or in to bitfield value.
323    HighVal = Builder.CreateShl(HighVal,
324                                llvm::ConstantInt::get(EltTy, LowBits));
325    Val = Builder.CreateOr(Val, HighVal, "bf.val");
326  }
327
328  // Sign extend if necessary.
329  if (LV.isBitfieldSigned()) {
330    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
331                                                    EltTySize - BitfieldSize);
332    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
333                             ExtraBits, "bf.val.sext");
334  }
335
336  // The bitfield type and the normal type differ when the storage sizes
337  // differ (currently just _Bool).
338  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
339
340  return RValue::get(Val);
341}
342
343RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
344                                                    QualType ExprType) {
345  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
346}
347
348RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
349                                               QualType ExprType) {
350  return EmitObjCPropertyGet(LV.getKVCRefExpr());
351}
352
353// If this is a reference to a subset of the elements of a vector, create an
354// appropriate shufflevector.
355RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
356                                                         QualType ExprType) {
357  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
358                                        LV.isVolatileQualified(), "tmp");
359
360  const llvm::Constant *Elts = LV.getExtVectorElts();
361
362  // If the result of the expression is a non-vector type, we must be
363  // extracting a single element.  Just codegen as an extractelement.
364  const VectorType *ExprVT = ExprType->getAsVectorType();
365  if (!ExprVT) {
366    unsigned InIdx = getAccessedFieldNo(0, Elts);
367    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
368    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
369  }
370
371  // Always use shuffle vector to try to retain the original program structure
372  unsigned NumResultElts = ExprVT->getNumElements();
373
374  llvm::SmallVector<llvm::Constant*, 4> Mask;
375  for (unsigned i = 0; i != NumResultElts; ++i) {
376    unsigned InIdx = getAccessedFieldNo(i, Elts);
377    Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
378  }
379
380  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
381  Vec = Builder.CreateShuffleVector(Vec,
382                                    llvm::UndefValue::get(Vec->getType()),
383                                    MaskV, "tmp");
384  return RValue::get(Vec);
385}
386
387
388
389/// EmitStoreThroughLValue - Store the specified rvalue into the specified
390/// lvalue, where both are guaranteed to the have the same type, and that type
391/// is 'Ty'.
392void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
393                                             QualType Ty) {
394  if (!Dst.isSimple()) {
395    if (Dst.isVectorElt()) {
396      // Read/modify/write the vector, inserting the new element.
397      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
398                                            Dst.isVolatileQualified(), "tmp");
399      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
400                                        Dst.getVectorIdx(), "vecins");
401      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
402      return;
403    }
404
405    // If this is an update of extended vector elements, insert them as
406    // appropriate.
407    if (Dst.isExtVectorElt())
408      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
409
410    if (Dst.isBitfield())
411      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
412
413    if (Dst.isPropertyRef())
414      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
415
416    if (Dst.isKVCRef())
417      return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
418
419    assert(0 && "Unknown LValue type");
420  }
421
422  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
423    // load of a __weak object.
424    llvm::Value *LvalueDst = Dst.getAddress();
425    llvm::Value *src = Src.getScalarVal();
426     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
427    return;
428  }
429
430  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
431    // load of a __strong object.
432    llvm::Value *LvalueDst = Dst.getAddress();
433    llvm::Value *src = Src.getScalarVal();
434#if 0
435    // FIXME. We cannot positively determine if we have an 'ivar' assignment,
436    // object assignment or an unknown assignment. For now, generate call to
437    // objc_assign_strongCast assignment which is a safe, but consevative
438    // assumption.
439    if (Dst.isObjCIvar())
440      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, LvalueDst);
441    else
442      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
443#endif
444    if (Dst.isGlobalObjCRef())
445      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
446    else
447      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
448    return;
449  }
450
451  assert(Src.isScalar() && "Can't emit an agg store with this method");
452  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
453                    Dst.isVolatileQualified(), Ty);
454}
455
456void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
457                                                     QualType Ty,
458                                                     llvm::Value **Result) {
459  unsigned StartBit = Dst.getBitfieldStartBit();
460  unsigned BitfieldSize = Dst.getBitfieldSize();
461  llvm::Value *Ptr = Dst.getBitfieldAddr();
462
463  const llvm::Type *EltTy =
464    cast<llvm::PointerType>(Ptr->getType())->getElementType();
465  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
466
467  // Get the new value, cast to the appropriate type and masked to
468  // exactly the size of the bit-field.
469  llvm::Value *SrcVal = Src.getScalarVal();
470  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
471  llvm::Constant *Mask =
472    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
473  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
474
475  // Return the new value of the bit-field, if requested.
476  if (Result) {
477    // Cast back to the proper type for result.
478    const llvm::Type *SrcTy = SrcVal->getType();
479    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
480                                                  "bf.reload.val");
481
482    // Sign extend if necessary.
483    if (Dst.isBitfieldSigned()) {
484      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
485      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
486                                                      SrcTySize - BitfieldSize);
487      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
488                                    ExtraBits, "bf.reload.sext");
489    }
490
491    *Result = SrcTrunc;
492  }
493
494  // In some cases the bitfield may straddle two memory locations.
495  // Emit the low part first and check to see if the high needs to be
496  // done.
497  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
498  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
499                                           "bf.prev.low");
500
501  // Compute the mask for zero-ing the low part of this bitfield.
502  llvm::Constant *InvMask =
503    llvm::ConstantInt::get(~llvm::APInt::getBitsSet(EltTySize, StartBit,
504                                                    StartBit + LowBits));
505
506  // Compute the new low part as
507  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
508  // with the shift of NewVal implicitly stripping the high bits.
509  llvm::Value *NewLowVal =
510    Builder.CreateShl(NewVal, llvm::ConstantInt::get(EltTy, StartBit),
511                      "bf.value.lo");
512  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
513  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
514
515  // Write back.
516  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
517
518  // If the low part doesn't cover the bitfield emit a high part.
519  if (LowBits < BitfieldSize) {
520    unsigned HighBits = BitfieldSize - LowBits;
521    llvm::Value *HighPtr =
522      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
523                        "bf.ptr.hi");
524    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
525                                              Dst.isVolatileQualified(),
526                                              "bf.prev.hi");
527
528    // Compute the mask for zero-ing the high part of this bitfield.
529    llvm::Constant *InvMask =
530      llvm::ConstantInt::get(~llvm::APInt::getLowBitsSet(EltTySize, HighBits));
531
532    // Compute the new high part as
533    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
534    // where the high bits of NewVal have already been cleared and the
535    // shift stripping the low bits.
536    llvm::Value *NewHighVal =
537      Builder.CreateLShr(NewVal, llvm::ConstantInt::get(EltTy, LowBits),
538                        "bf.value.high");
539    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
540    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
541
542    // Write back.
543    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
544  }
545}
546
547void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
548                                                        LValue Dst,
549                                                        QualType Ty) {
550  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
551}
552
553void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
554                                                   LValue Dst,
555                                                   QualType Ty) {
556  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
557}
558
559void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
560                                                               LValue Dst,
561                                                               QualType Ty) {
562  // This access turns into a read/modify/write of the vector.  Load the input
563  // value now.
564  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
565                                        Dst.isVolatileQualified(), "tmp");
566  const llvm::Constant *Elts = Dst.getExtVectorElts();
567
568  llvm::Value *SrcVal = Src.getScalarVal();
569
570  if (const VectorType *VTy = Ty->getAsVectorType()) {
571    unsigned NumSrcElts = VTy->getNumElements();
572    unsigned NumDstElts =
573       cast<llvm::VectorType>(Vec->getType())->getNumElements();
574    if (NumDstElts == NumSrcElts) {
575      // Use shuffle vector is the src and destination are the same number
576      // of elements
577      llvm::SmallVector<llvm::Constant*, 4> Mask;
578      for (unsigned i = 0; i != NumSrcElts; ++i) {
579        unsigned InIdx = getAccessedFieldNo(i, Elts);
580        Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
581      }
582
583      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
584      Vec = Builder.CreateShuffleVector(SrcVal,
585                                        llvm::UndefValue::get(Vec->getType()),
586                                        MaskV, "tmp");
587    }
588    else if (NumDstElts > NumSrcElts) {
589      // Extended the source vector to the same length and then shuffle it
590      // into the destination.
591      // FIXME: since we're shuffling with undef, can we just use the indices
592      //        into that?  This could be simpler.
593      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
594      unsigned i;
595      for (i = 0; i != NumSrcElts; ++i)
596        ExtMask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
597      for (; i != NumDstElts; ++i)
598        ExtMask.push_back(llvm::UndefValue::get(llvm::Type::Int32Ty));
599      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
600                                                        ExtMask.size());
601      llvm::Value *ExtSrcVal =
602        Builder.CreateShuffleVector(SrcVal,
603                                    llvm::UndefValue::get(SrcVal->getType()),
604                                    ExtMaskV, "tmp");
605      // build identity
606      llvm::SmallVector<llvm::Constant*, 4> Mask;
607      for (unsigned i = 0; i != NumDstElts; ++i) {
608        Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
609      }
610      // modify when what gets shuffled in
611      for (unsigned i = 0; i != NumSrcElts; ++i) {
612        unsigned Idx = getAccessedFieldNo(i, Elts);
613        Mask[Idx] =llvm::ConstantInt::get(llvm::Type::Int32Ty, i+NumDstElts);
614      }
615      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
616      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
617    }
618    else {
619      // We should never shorten the vector
620      assert(0 && "unexpected shorten vector length");
621    }
622  } else {
623    // If the Src is a scalar (not a vector) it must be updating one element.
624    unsigned InIdx = getAccessedFieldNo(0, Elts);
625    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
626    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
627  }
628
629  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
630}
631
632LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
633  const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
634
635  if (VD && (VD->isBlockVarDecl() || isa<ParmVarDecl>(VD) ||
636        isa<ImplicitParamDecl>(VD))) {
637    LValue LV;
638    bool GCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
639    if (VD->hasExternalStorage()) {
640      LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
641                            E->getType().getCVRQualifiers(),
642                            getContext().getObjCGCAttrKind(E->getType()));
643    }
644    else {
645      llvm::Value *V = LocalDeclMap[VD];
646      assert(V && "DeclRefExpr not entered in LocalDeclMap?");
647      // local variables do not get their gc attribute set.
648      QualType::GCAttrTypes attr = QualType::GCNone;
649      // local static?
650      if (!GCable)
651        attr = getContext().getObjCGCAttrKind(E->getType());
652      if (VD->hasAttr<BlocksAttr>()) {
653        bool needsCopyDispose = BlockRequiresCopying(VD->getType());
654        const llvm::Type *PtrStructTy = V->getType();
655        const llvm::Type *Ty = PtrStructTy;
656        Ty = llvm::PointerType::get(Ty, 0);
657        V = Builder.CreateStructGEP(V, 1, "forwarding");
658        V = Builder.CreateBitCast(V, Ty);
659        V = Builder.CreateLoad(V, false);
660        V = Builder.CreateBitCast(V, PtrStructTy);
661        V = Builder.CreateStructGEP(V, needsCopyDispose*2 + 4, "x");
662      }
663      LV = LValue::MakeAddr(V, E->getType().getCVRQualifiers(), attr);
664    }
665    LValue::SetObjCNonGC(LV, GCable);
666    return LV;
667  } else if (VD && VD->isFileVarDecl()) {
668    LValue LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
669                                 E->getType().getCVRQualifiers(),
670                                 getContext().getObjCGCAttrKind(E->getType()));
671    if (LV.isObjCStrong())
672      LV.SetGlobalObjCRef(LV, true);
673    return LV;
674  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) {
675    return LValue::MakeAddr(CGM.GetAddrOfFunction(GlobalDecl(FD)),
676                            E->getType().getCVRQualifiers(),
677                            getContext().getObjCGCAttrKind(E->getType()));
678  }
679  else if (const ImplicitParamDecl *IPD =
680      dyn_cast<ImplicitParamDecl>(E->getDecl())) {
681    llvm::Value *V = LocalDeclMap[IPD];
682    assert(V && "BlockVarDecl not entered in LocalDeclMap?");
683    return LValue::MakeAddr(V, E->getType().getCVRQualifiers(),
684                            getContext().getObjCGCAttrKind(E->getType()));
685  }
686  assert(0 && "Unimp declref");
687  //an invalid LValue, but the assert will
688  //ensure that this point is never reached.
689  return LValue();
690}
691
692LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
693  return LValue::MakeAddr(GetAddrOfBlockDecl(E), 0);
694}
695
696LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
697  // __extension__ doesn't affect lvalue-ness.
698  if (E->getOpcode() == UnaryOperator::Extension)
699    return EmitLValue(E->getSubExpr());
700
701  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
702  switch (E->getOpcode()) {
703  default: assert(0 && "Unknown unary operator lvalue!");
704  case UnaryOperator::Deref:
705    {
706      QualType T =
707        E->getSubExpr()->getType()->getAsPointerType()->getPointeeType();
708      LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()),
709                                   ExprTy->getAsPointerType()->getPointeeType()
710                                      .getCVRQualifiers(),
711                                   getContext().getObjCGCAttrKind(T));
712     // We should not generate __weak write barrier on indirect reference
713     // of a pointer to object; as in void foo (__weak id *param); *param = 0;
714     // But, we continue to generate __strong write barrier on indirect write
715     // into a pointer to object.
716     if (getContext().getLangOptions().ObjC1 &&
717         getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
718         LV.isObjCWeak())
719       LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate());
720     return LV;
721    }
722  case UnaryOperator::Real:
723  case UnaryOperator::Imag:
724    LValue LV = EmitLValue(E->getSubExpr());
725    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
726    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
727                                                    Idx, "idx"),
728                            ExprTy.getCVRQualifiers());
729  }
730}
731
732LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
733  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E), 0);
734}
735
736LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
737  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E), 0);
738}
739
740
741LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
742  std::string GlobalVarName;
743
744  switch (Type) {
745  default:
746    assert(0 && "Invalid type");
747  case PredefinedExpr::Func:
748    GlobalVarName = "__func__.";
749    break;
750  case PredefinedExpr::Function:
751    GlobalVarName = "__FUNCTION__.";
752    break;
753  case PredefinedExpr::PrettyFunction:
754    // FIXME:: Demangle C++ method names
755    GlobalVarName = "__PRETTY_FUNCTION__.";
756    break;
757  }
758
759  // FIXME: This isn't right at all.  The logic for computing this should go
760  // into a method on PredefinedExpr.  This would allow sema and codegen to be
761  // consistent for things like sizeof(__func__) etc.
762  std::string FunctionName;
763  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(CurCodeDecl)) {
764    FunctionName = CGM.getMangledName(FD);
765  } else {
766    // Just get the mangled name; skipping the asm prefix if it
767    // exists.
768    FunctionName = CurFn->getName();
769    if (FunctionName[0] == '\01')
770      FunctionName = FunctionName.substr(1, std::string::npos);
771  }
772
773  GlobalVarName += FunctionName;
774  llvm::Constant *C =
775    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
776  return LValue::MakeAddr(C, 0);
777}
778
779LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
780  switch (E->getIdentType()) {
781  default:
782    return EmitUnsupportedLValue(E, "predefined expression");
783  case PredefinedExpr::Func:
784  case PredefinedExpr::Function:
785  case PredefinedExpr::PrettyFunction:
786    return EmitPredefinedFunctionName(E->getIdentType());
787  }
788}
789
790LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
791  // The index must always be an integer, which is not an aggregate.  Emit it.
792  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
793
794  // If the base is a vector type, then we are forming a vector element lvalue
795  // with this subscript.
796  if (E->getBase()->getType()->isVectorType()) {
797    // Emit the vector as an lvalue to get its address.
798    LValue LHS = EmitLValue(E->getBase());
799    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
800    // FIXME: This should properly sign/zero/extend or truncate Idx to i32.
801    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
802      E->getBase()->getType().getCVRQualifiers());
803  }
804
805  // The base must be a pointer, which is not an aggregate.  Emit it.
806  llvm::Value *Base = EmitScalarExpr(E->getBase());
807
808  // Extend or truncate the index type to 32 or 64-bits.
809  QualType IdxTy  = E->getIdx()->getType();
810  bool IdxSigned = IdxTy->isSignedIntegerType();
811  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
812  if (IdxBitwidth != LLVMPointerWidth)
813    Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(LLVMPointerWidth),
814                                IdxSigned, "idxprom");
815
816  // We know that the pointer points to a type of the correct size,
817  // unless the size is a VLA or Objective-C interface.
818  llvm::Value *Address = 0;
819  if (const VariableArrayType *VAT =
820        getContext().getAsVariableArrayType(E->getType())) {
821    llvm::Value *VLASize = VLASizeMap[VAT];
822
823    Idx = Builder.CreateMul(Idx, VLASize);
824
825    QualType BaseType = getContext().getBaseElementType(VAT);
826
827    uint64_t BaseTypeSize = getContext().getTypeSize(BaseType) / 8;
828    Idx = Builder.CreateUDiv(Idx,
829                             llvm::ConstantInt::get(Idx->getType(),
830                                                    BaseTypeSize));
831    Address = Builder.CreateGEP(Base, Idx, "arrayidx");
832  } else if (const ObjCInterfaceType *OIT =
833             dyn_cast<ObjCInterfaceType>(E->getType())) {
834    llvm::Value *InterfaceSize =
835      llvm::ConstantInt::get(Idx->getType(),
836                             getContext().getTypeSize(OIT) / 8);
837
838    Idx = Builder.CreateMul(Idx, InterfaceSize);
839
840    llvm::Type *i8PTy = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
841    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
842                                Idx, "arrayidx");
843    Address = Builder.CreateBitCast(Address, Base->getType());
844  } else {
845    Address = Builder.CreateGEP(Base, Idx, "arrayidx");
846  }
847
848  QualType T = E->getBase()->getType()->getAsPointerType()->getPointeeType();
849  LValue LV = LValue::MakeAddr(Address,
850                               T.getCVRQualifiers(),
851                               getContext().getObjCGCAttrKind(T));
852  if (getContext().getLangOptions().ObjC1 &&
853      getContext().getLangOptions().getGCMode() != LangOptions::NonGC)
854    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate());
855  return LV;
856}
857
858static
859llvm::Constant *GenerateConstantVector(llvm::SmallVector<unsigned, 4> &Elts) {
860  llvm::SmallVector<llvm::Constant *, 4> CElts;
861
862  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
863    CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, Elts[i]));
864
865  return llvm::ConstantVector::get(&CElts[0], CElts.size());
866}
867
868LValue CodeGenFunction::
869EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
870  // Emit the base vector as an l-value.
871  LValue Base;
872
873  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
874  if (!E->isArrow()) {
875    assert(E->getBase()->getType()->isVectorType());
876    Base = EmitLValue(E->getBase());
877  } else {
878    const PointerType *PT = E->getBase()->getType()->getAsPointerType();
879    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
880    Base = LValue::MakeAddr(Ptr, PT->getPointeeType().getCVRQualifiers());
881  }
882
883  // Encode the element access list into a vector of unsigned indices.
884  llvm::SmallVector<unsigned, 4> Indices;
885  E->getEncodedElementAccess(Indices);
886
887  if (Base.isSimple()) {
888    llvm::Constant *CV = GenerateConstantVector(Indices);
889    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
890                                    Base.getQualifiers());
891  }
892  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
893
894  llvm::Constant *BaseElts = Base.getExtVectorElts();
895  llvm::SmallVector<llvm::Constant *, 4> CElts;
896
897  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
898    if (isa<llvm::ConstantAggregateZero>(BaseElts))
899      CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
900    else
901      CElts.push_back(BaseElts->getOperand(Indices[i]));
902  }
903  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
904  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
905                                  Base.getQualifiers());
906}
907
908LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
909  bool isUnion = false;
910  bool isIvar = false;
911  bool isNonGC = false;
912  Expr *BaseExpr = E->getBase();
913  llvm::Value *BaseValue = NULL;
914  unsigned CVRQualifiers=0;
915
916  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
917  if (E->isArrow()) {
918    BaseValue = EmitScalarExpr(BaseExpr);
919    const PointerType *PTy =
920      BaseExpr->getType()->getAsPointerType();
921    if (PTy->getPointeeType()->isUnionType())
922      isUnion = true;
923    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
924  } else if (isa<ObjCPropertyRefExpr>(BaseExpr) ||
925             isa<ObjCKVCRefExpr>(BaseExpr)) {
926    RValue RV = EmitObjCPropertyGet(BaseExpr);
927    BaseValue = RV.getAggregateAddr();
928    if (BaseExpr->getType()->isUnionType())
929      isUnion = true;
930    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
931  } else {
932    LValue BaseLV = EmitLValue(BaseExpr);
933    if (BaseLV.isObjCIvar())
934      isIvar = true;
935    if (BaseLV.isNonGC())
936      isNonGC = true;
937    // FIXME: this isn't right for bitfields.
938    BaseValue = BaseLV.getAddress();
939    if (BaseExpr->getType()->isUnionType())
940      isUnion = true;
941    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
942  }
943
944  FieldDecl *Field = dyn_cast<FieldDecl>(E->getMemberDecl());
945  // FIXME: Handle non-field member expressions
946  assert(Field && "No code generation for non-field member references");
947  LValue MemExpLV = EmitLValueForField(BaseValue, Field, isUnion,
948                                       CVRQualifiers);
949  LValue::SetObjCIvar(MemExpLV, isIvar);
950  LValue::SetObjCNonGC(MemExpLV, isNonGC);
951  return MemExpLV;
952}
953
954LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
955                                              FieldDecl* Field,
956                                              unsigned CVRQualifiers) {
957   unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
958  // FIXME: CodeGenTypes should expose a method to get the appropriate type for
959  // FieldTy (the appropriate type is ABI-dependent).
960  const llvm::Type *FieldTy =
961    CGM.getTypes().ConvertTypeForMem(Field->getType());
962  const llvm::PointerType *BaseTy =
963  cast<llvm::PointerType>(BaseValue->getType());
964  unsigned AS = BaseTy->getAddressSpace();
965  BaseValue = Builder.CreateBitCast(BaseValue,
966                                    llvm::PointerType::get(FieldTy, AS),
967                                    "tmp");
968  llvm::Value *V = Builder.CreateGEP(BaseValue,
969                              llvm::ConstantInt::get(llvm::Type::Int32Ty, idx),
970                              "tmp");
971
972  CodeGenTypes::BitFieldInfo bitFieldInfo =
973    CGM.getTypes().getBitFieldInfo(Field);
974  return LValue::MakeBitfield(V, bitFieldInfo.Begin, bitFieldInfo.Size,
975                              Field->getType()->isSignedIntegerType(),
976                            Field->getType().getCVRQualifiers()|CVRQualifiers);
977}
978
979LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
980                                           FieldDecl* Field,
981                                           bool isUnion,
982                                           unsigned CVRQualifiers)
983{
984  if (Field->isBitField())
985    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
986
987  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
988  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
989
990  // Match union field type.
991  if (isUnion) {
992    const llvm::Type *FieldTy =
993      CGM.getTypes().ConvertTypeForMem(Field->getType());
994    const llvm::PointerType * BaseTy =
995      cast<llvm::PointerType>(BaseValue->getType());
996    unsigned AS = BaseTy->getAddressSpace();
997    V = Builder.CreateBitCast(V,
998                              llvm::PointerType::get(FieldTy, AS),
999                              "tmp");
1000  }
1001
1002  QualType::GCAttrTypes attr = QualType::GCNone;
1003  if (CGM.getLangOptions().ObjC1 &&
1004      CGM.getLangOptions().getGCMode() != LangOptions::NonGC) {
1005    QualType Ty = Field->getType();
1006    attr = Ty.getObjCGCAttr();
1007    if (attr != QualType::GCNone) {
1008      // __weak attribute on a field is ignored.
1009      if (attr == QualType::Weak)
1010        attr = QualType::GCNone;
1011    }
1012    else if (getContext().isObjCObjectPointerType(Ty))
1013      attr = QualType::Strong;
1014  }
1015  LValue LV =
1016    LValue::MakeAddr(V,
1017                     Field->getType().getCVRQualifiers()|CVRQualifiers,
1018                     attr);
1019  return LV;
1020}
1021
1022LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1023  const llvm::Type *LTy = ConvertType(E->getType());
1024  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
1025
1026  const Expr* InitExpr = E->getInitializer();
1027  LValue Result = LValue::MakeAddr(DeclPtr, E->getType().getCVRQualifiers());
1028
1029  if (E->getType()->isComplexType()) {
1030    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1031  } else if (hasAggregateLLVMType(E->getType())) {
1032    EmitAnyExpr(InitExpr, DeclPtr, false);
1033  } else {
1034    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1035  }
1036
1037  return Result;
1038}
1039
1040LValue CodeGenFunction::EmitConditionalOperator(const ConditionalOperator* E) {
1041  // We don't handle vectors yet.
1042  if (E->getType()->isVectorType())
1043    return EmitUnsupportedLValue(E, "conditional operator");
1044
1045  // ?: here should be an aggregate.
1046  assert((hasAggregateLLVMType(E->getType()) &&
1047          !E->getType()->isAnyComplexType()) &&
1048         "Unexpected conditional operator!");
1049
1050  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1051  EmitAggExpr(E, Temp, false);
1052
1053  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1054                          getContext().getObjCGCAttrKind(E->getType()));
1055
1056}
1057
1058/// EmitCastLValue - Casts are never lvalues.  If a cast is needed by the code
1059/// generator in an lvalue context, then it must mean that we need the address
1060/// of an aggregate in order to access one of its fields.  This can happen for
1061/// all the reasons that casts are permitted with aggregate result, including
1062/// noop aggregate casts, and cast from scalar to union.
1063LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1064  // If this is an aggregate-to-aggregate cast, just use the input's address as
1065  // the lvalue.
1066  if (getContext().hasSameUnqualifiedType(E->getType(),
1067                                          E->getSubExpr()->getType()))
1068    return EmitLValue(E->getSubExpr());
1069
1070  // Otherwise, we must have a cast from scalar to union.
1071  assert(E->getType()->isUnionType() && "Expected scalar-to-union cast");
1072
1073  // Casts are only lvalues when the source and destination types are the same.
1074  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1075  EmitAnyExpr(E->getSubExpr(), Temp, false);
1076
1077  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1078                          getContext().getObjCGCAttrKind(E->getType()));
1079}
1080
1081//===--------------------------------------------------------------------===//
1082//                             Expression Emission
1083//===--------------------------------------------------------------------===//
1084
1085
1086RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
1087  // Builtins never have block type.
1088  if (E->getCallee()->getType()->isBlockPointerType())
1089    return EmitBlockCallExpr(E);
1090
1091  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1092    return EmitCXXMemberCallExpr(CE);
1093
1094  const Decl *TargetDecl = 0;
1095  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1096    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1097      TargetDecl = DRE->getDecl();
1098      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1099        if (unsigned builtinID = FD->getBuiltinID(getContext()))
1100          return EmitBuiltinExpr(FD, builtinID, E);
1101    }
1102  }
1103
1104  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1105  return EmitCallExpr(Callee, E->getCallee()->getType(),
1106                      E->arg_begin(), E->arg_end(), TargetDecl);
1107}
1108
1109LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1110  // Comma expressions just emit their LHS then their RHS as an l-value.
1111  if (E->getOpcode() == BinaryOperator::Comma) {
1112    EmitAnyExpr(E->getLHS());
1113    return EmitLValue(E->getRHS());
1114  }
1115
1116  // Can only get l-value for binary operator expressions which are a
1117  // simple assignment of aggregate type.
1118  if (E->getOpcode() != BinaryOperator::Assign)
1119    return EmitUnsupportedLValue(E, "binary l-value expression");
1120
1121  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1122  EmitAggExpr(E, Temp, false);
1123  // FIXME: Are these qualifiers correct?
1124  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1125                          getContext().getObjCGCAttrKind(E->getType()));
1126}
1127
1128LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1129  // Can only get l-value for call expression returning aggregate type
1130  RValue RV = EmitCallExpr(E);
1131  return LValue::MakeAddr(RV.getAggregateAddr(),
1132                          E->getType().getCVRQualifiers(),
1133                          getContext().getObjCGCAttrKind(E->getType()));
1134}
1135
1136LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1137  // FIXME: This shouldn't require another copy.
1138  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1139  EmitAggExpr(E, Temp, false);
1140  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers());
1141}
1142
1143LValue
1144CodeGenFunction::EmitCXXConditionDeclLValue(const CXXConditionDeclExpr *E) {
1145  EmitLocalBlockVarDecl(*E->getVarDecl());
1146  return EmitDeclRefLValue(E);
1147}
1148
1149LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1150  // Can only get l-value for message expression returning aggregate type
1151  RValue RV = EmitObjCMessageExpr(E);
1152  // FIXME: can this be volatile?
1153  return LValue::MakeAddr(RV.getAggregateAddr(),
1154                          E->getType().getCVRQualifiers(),
1155                          getContext().getObjCGCAttrKind(E->getType()));
1156}
1157
1158llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1159                                             const ObjCIvarDecl *Ivar) {
1160  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1161}
1162
1163LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1164                                          llvm::Value *BaseValue,
1165                                          const ObjCIvarDecl *Ivar,
1166                                          unsigned CVRQualifiers) {
1167  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1168                                                   Ivar, CVRQualifiers);
1169}
1170
1171LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1172  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1173  llvm::Value *BaseValue = 0;
1174  const Expr *BaseExpr = E->getBase();
1175  unsigned CVRQualifiers = 0;
1176  QualType ObjectTy;
1177  if (E->isArrow()) {
1178    BaseValue = EmitScalarExpr(BaseExpr);
1179    const PointerType *PTy = BaseExpr->getType()->getAsPointerType();
1180    ObjectTy = PTy->getPointeeType();
1181    CVRQualifiers = ObjectTy.getCVRQualifiers();
1182  } else {
1183    LValue BaseLV = EmitLValue(BaseExpr);
1184    // FIXME: this isn't right for bitfields.
1185    BaseValue = BaseLV.getAddress();
1186    ObjectTy = BaseExpr->getType();
1187    CVRQualifiers = ObjectTy.getCVRQualifiers();
1188  }
1189
1190  return EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(), CVRQualifiers);
1191}
1192
1193LValue
1194CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1195  // This is a special l-value that just issues sends when we load or
1196  // store through it.
1197  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1198}
1199
1200LValue
1201CodeGenFunction::EmitObjCKVCRefLValue(const ObjCKVCRefExpr *E) {
1202  // This is a special l-value that just issues sends when we load or
1203  // store through it.
1204  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1205}
1206
1207LValue
1208CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1209  return EmitUnsupportedLValue(E, "use of super");
1210}
1211
1212LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1213
1214  // Can only get l-value for message expression returning aggregate type
1215  RValue RV = EmitAnyExprToTemp(E);
1216  // FIXME: can this be volatile?
1217  return LValue::MakeAddr(RV.getAggregateAddr(),
1218                          E->getType().getCVRQualifiers(),
1219                          getContext().getObjCGCAttrKind(E->getType()));
1220}
1221
1222
1223RValue CodeGenFunction::EmitCallExpr(llvm::Value *Callee, QualType CalleeType,
1224                                     CallExpr::const_arg_iterator ArgBeg,
1225                                     CallExpr::const_arg_iterator ArgEnd,
1226                                     const Decl *TargetDecl) {
1227  // Get the actual function type. The callee type will always be a
1228  // pointer to function type or a block pointer type.
1229  assert(CalleeType->isFunctionPointerType() &&
1230         "Call must have function pointer type!");
1231
1232  QualType FnType = CalleeType->getAsPointerType()->getPointeeType();
1233  QualType ResultType = FnType->getAsFunctionType()->getResultType();
1234
1235  CallArgList Args;
1236  EmitCallArgs(Args, FnType->getAsFunctionProtoType(), ArgBeg, ArgEnd);
1237
1238  return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args),
1239                  Callee, Args, TargetDecl);
1240}
1241