CGExpr.cpp revision f1466848dce9c4c75d96a6cabdc8db560e26aac8 
1//===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This contains code to emit Expr nodes as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CodeGenModule.h"
16#include "CGCall.h"
17#include "CGObjCRuntime.h"
18#include "clang/AST/ASTContext.h"
19#include "clang/AST/DeclObjC.h"
20#include "llvm/Target/TargetData.h"
21using namespace clang;
22using namespace CodeGen;
23
24//===--------------------------------------------------------------------===//
25//                        Miscellaneous Helper Methods
26//===--------------------------------------------------------------------===//
27
28/// CreateTempAlloca - This creates a alloca and inserts it into the entry
29/// block.
30llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
31                                                    const char *Name) {
32  if (!Builder.isNamePreserving())
33    Name = "";
34  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
35}
36
37/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
38/// expression and compare the result against zero, returning an Int1Ty value.
39llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
40  QualType BoolTy = getContext().BoolTy;
41  if (!E->getType()->isAnyComplexType())
42    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
43
44  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
45}
46
47/// EmitAnyExpr - Emit code to compute the specified expression which can have
48/// any type.  The result is returned as an RValue struct.  If this is an
49/// aggregate expression, the aggloc/agglocvolatile arguments indicate where
50/// the result should be returned.
51RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
52                                    bool isAggLocVolatile) {
53  if (!hasAggregateLLVMType(E->getType()))
54    return RValue::get(EmitScalarExpr(E));
55  else if (E->getType()->isAnyComplexType())
56    return RValue::getComplex(EmitComplexExpr(E));
57
58  EmitAggExpr(E, AggLoc, isAggLocVolatile);
59  return RValue::getAggregate(AggLoc);
60}
61
62/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result
63/// will always be accessible even if no aggregate location is
64/// provided.
65RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E, llvm::Value *AggLoc,
66                                          bool isAggLocVolatile) {
67  if (!AggLoc && hasAggregateLLVMType(E->getType()) &&
68      !E->getType()->isAnyComplexType())
69    AggLoc = CreateTempAlloca(ConvertType(E->getType()), "agg.tmp");
70  return EmitAnyExpr(E, AggLoc, isAggLocVolatile);
71}
72
73/// getAccessedFieldNo - Given an encoded value and a result number, return
74/// the input field number being accessed.
75unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
76                                             const llvm::Constant *Elts) {
77  if (isa<llvm::ConstantAggregateZero>(Elts))
78    return 0;
79
80  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
81}
82
83
84//===----------------------------------------------------------------------===//
85//                         LValue Expression Emission
86//===----------------------------------------------------------------------===//
87
88RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
89  if (Ty->isVoidType()) {
90    return RValue::get(0);
91  } else if (const ComplexType *CTy = Ty->getAsComplexType()) {
92    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
93    llvm::Value *U = llvm::UndefValue::get(EltTy);
94    return RValue::getComplex(std::make_pair(U, U));
95  } else if (hasAggregateLLVMType(Ty)) {
96    const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
97    return RValue::getAggregate(llvm::UndefValue::get(LTy));
98  } else {
99    return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
100  }
101}
102
103RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
104                                              const char *Name) {
105  ErrorUnsupported(E, Name);
106  return GetUndefRValue(E->getType());
107}
108
109LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
110                                              const char *Name) {
111  ErrorUnsupported(E, Name);
112  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
113  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
114                          E->getType().getCVRQualifiers(),
115                          getContext().getObjCGCAttrKind(E->getType()));
116}
117
118/// EmitLValue - Emit code to compute a designator that specifies the location
119/// of the expression.
120///
121/// This can return one of two things: a simple address or a bitfield
122/// reference.  In either case, the LLVM Value* in the LValue structure is
123/// guaranteed to be an LLVM pointer type.
124///
125/// If this returns a bitfield reference, nothing about the pointee type of
126/// the LLVM value is known: For example, it may not be a pointer to an
127/// integer.
128///
129/// If this returns a normal address, and if the lvalue's C type is fixed
130/// size, this method guarantees that the returned pointer type will point to
131/// an LLVM type of the same size of the lvalue's type.  If the lvalue has a
132/// variable length type, this is not possible.
133///
134LValue CodeGenFunction::EmitLValue(const Expr *E) {
135  switch (E->getStmtClass()) {
136  default: return EmitUnsupportedLValue(E, "l-value expression");
137
138  case Expr::BinaryOperatorClass:
139    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
140  case Expr::CallExprClass:
141  case Expr::CXXOperatorCallExprClass:
142    return EmitCallExprLValue(cast<CallExpr>(E));
143  case Expr::VAArgExprClass:
144    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
145  case Expr::DeclRefExprClass:
146  case Expr::QualifiedDeclRefExprClass:
147    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
148  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
149  case Expr::PredefinedExprClass:
150    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
151  case Expr::StringLiteralClass:
152    return EmitStringLiteralLValue(cast<StringLiteral>(E));
153  case Expr::ObjCEncodeExprClass:
154    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
155
156  case Expr::BlockDeclRefExprClass:
157    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
158
159  case Expr::CXXConditionDeclExprClass:
160    return EmitCXXConditionDeclLValue(cast<CXXConditionDeclExpr>(E));
161
162  case Expr::ObjCMessageExprClass:
163    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
164  case Expr::ObjCIvarRefExprClass:
165    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
166  case Expr::ObjCPropertyRefExprClass:
167    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
168  case Expr::ObjCKVCRefExprClass:
169    return EmitObjCKVCRefLValue(cast<ObjCKVCRefExpr>(E));
170  case Expr::ObjCSuperExprClass:
171    return EmitObjCSuperExpr(cast<ObjCSuperExpr>(E));
172
173  case Expr::UnaryOperatorClass:
174    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
175  case Expr::ArraySubscriptExprClass:
176    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
177  case Expr::ExtVectorElementExprClass:
178    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
179  case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
180  case Expr::CompoundLiteralExprClass:
181    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
182  case Expr::ChooseExprClass:
183    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
184  case Expr::ImplicitCastExprClass:
185  case Expr::CStyleCastExprClass:
186  case Expr::CXXFunctionalCastExprClass:
187  case Expr::CXXStaticCastExprClass:
188  case Expr::CXXDynamicCastExprClass:
189  case Expr::CXXReinterpretCastExprClass:
190  case Expr::CXXConstCastExprClass:
191    return EmitCastLValue(cast<CastExpr>(E));
192  }
193}
194
195llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
196                                               QualType Ty) {
197  llvm::Value *V = Builder.CreateLoad(Addr, Volatile, "tmp");
198
199  // Bool can have different representation in memory than in
200  // registers.
201  if (Ty->isBooleanType())
202    if (V->getType() != llvm::Type::Int1Ty)
203      V = Builder.CreateTrunc(V, llvm::Type::Int1Ty, "tobool");
204
205  return V;
206}
207
208void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
209                                        bool Volatile) {
210  // Handle stores of types which have different representations in
211  // memory and as LLVM values.
212
213  // FIXME: We shouldn't be this loose, we should only do this
214  // conversion when we have a type we know has a different memory
215  // representation (e.g., bool).
216
217  const llvm::Type *SrcTy = Value->getType();
218  const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
219  if (DstPtr->getElementType() != SrcTy) {
220    const llvm::Type *MemTy =
221      llvm::PointerType::get(SrcTy, DstPtr->getAddressSpace());
222    Addr = Builder.CreateBitCast(Addr, MemTy, "storetmp");
223  }
224
225  Builder.CreateStore(Value, Addr, Volatile);
226}
227
228/// EmitLoadOfLValue - Given an expression that represents a value lvalue,
229/// this method emits the address of the lvalue, then loads the result as an
230/// rvalue, returning the rvalue.
231RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
232  if (LV.isObjCWeak()) {
233    // load of a __weak object.
234    llvm::Value *AddrWeakObj = LV.getAddress();
235    llvm::Value *read_weak = CGM.getObjCRuntime().EmitObjCWeakRead(*this,
236                                                                   AddrWeakObj);
237    return RValue::get(read_weak);
238  }
239
240  if (LV.isSimple()) {
241    llvm::Value *Ptr = LV.getAddress();
242    const llvm::Type *EltTy =
243      cast<llvm::PointerType>(Ptr->getType())->getElementType();
244
245    // Simple scalar l-value.
246    if (EltTy->isSingleValueType())
247      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
248                                          ExprType));
249
250    assert(ExprType->isFunctionType() && "Unknown scalar value");
251    return RValue::get(Ptr);
252  }
253
254  if (LV.isVectorElt()) {
255    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
256                                          LV.isVolatileQualified(), "tmp");
257    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
258                                                    "vecext"));
259  }
260
261  // If this is a reference to a subset of the elements of a vector, either
262  // shuffle the input or extract/insert them as appropriate.
263  if (LV.isExtVectorElt())
264    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
265
266  if (LV.isBitfield())
267    return EmitLoadOfBitfieldLValue(LV, ExprType);
268
269  if (LV.isPropertyRef())
270    return EmitLoadOfPropertyRefLValue(LV, ExprType);
271
272  assert(LV.isKVCRef() && "Unknown LValue type!");
273  return EmitLoadOfKVCRefLValue(LV, ExprType);
274}
275
276RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
277                                                 QualType ExprType) {
278  unsigned StartBit = LV.getBitfieldStartBit();
279  unsigned BitfieldSize = LV.getBitfieldSize();
280  llvm::Value *Ptr = LV.getBitfieldAddr();
281
282  const llvm::Type *EltTy =
283    cast<llvm::PointerType>(Ptr->getType())->getElementType();
284  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
285
286  // In some cases the bitfield may straddle two memory locations.
287  // Currently we load the entire bitfield, then do the magic to
288  // sign-extend it if necessary. This results in somewhat more code
289  // than necessary for the common case (one load), since two shifts
290  // accomplish both the masking and sign extension.
291  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
292  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
293
294  // Shift to proper location.
295  if (StartBit)
296    Val = Builder.CreateLShr(Val, llvm::ConstantInt::get(EltTy, StartBit),
297                             "bf.lo");
298
299  // Mask off unused bits.
300  llvm::Constant *LowMask =
301    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, LowBits));
302  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
303
304  // Fetch the high bits if necessary.
305  if (LowBits < BitfieldSize) {
306    unsigned HighBits = BitfieldSize - LowBits;
307    llvm::Value *HighPtr =
308      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
309                        "bf.ptr.hi");
310    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
311                                              LV.isVolatileQualified(),
312                                              "tmp");
313
314    // Mask off unused bits.
315    llvm::Constant *HighMask =
316      llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, HighBits));
317    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
318
319    // Shift to proper location and or in to bitfield value.
320    HighVal = Builder.CreateShl(HighVal,
321                                llvm::ConstantInt::get(EltTy, LowBits));
322    Val = Builder.CreateOr(Val, HighVal, "bf.val");
323  }
324
325  // Sign extend if necessary.
326  if (LV.isBitfieldSigned()) {
327    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
328                                                    EltTySize - BitfieldSize);
329    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
330                             ExtraBits, "bf.val.sext");
331  }
332
333  // The bitfield type and the normal type differ when the storage sizes
334  // differ (currently just _Bool).
335  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
336
337  return RValue::get(Val);
338}
339
340RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
341                                                    QualType ExprType) {
342  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
343}
344
345RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
346                                               QualType ExprType) {
347  return EmitObjCPropertyGet(LV.getKVCRefExpr());
348}
349
350// If this is a reference to a subset of the elements of a vector, create an
351// appropriate shufflevector.
352RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
353                                                         QualType ExprType) {
354  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
355                                        LV.isVolatileQualified(), "tmp");
356
357  const llvm::Constant *Elts = LV.getExtVectorElts();
358
359  // If the result of the expression is a non-vector type, we must be
360  // extracting a single element.  Just codegen as an extractelement.
361  const VectorType *ExprVT = ExprType->getAsVectorType();
362  if (!ExprVT) {
363    unsigned InIdx = getAccessedFieldNo(0, Elts);
364    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
365    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
366  }
367
368  // Always use shuffle vector to try to retain the original program structure
369  unsigned NumResultElts = ExprVT->getNumElements();
370
371  llvm::SmallVector<llvm::Constant*, 4> Mask;
372  for (unsigned i = 0; i != NumResultElts; ++i) {
373    unsigned InIdx = getAccessedFieldNo(i, Elts);
374    Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
375  }
376
377  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
378  Vec = Builder.CreateShuffleVector(Vec,
379                                    llvm::UndefValue::get(Vec->getType()),
380                                    MaskV, "tmp");
381  return RValue::get(Vec);
382}
383
384
385
386/// EmitStoreThroughLValue - Store the specified rvalue into the specified
387/// lvalue, where both are guaranteed to the have the same type, and that type
388/// is 'Ty'.
389void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
390                                             QualType Ty) {
391  if (!Dst.isSimple()) {
392    if (Dst.isVectorElt()) {
393      // Read/modify/write the vector, inserting the new element.
394      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
395                                            Dst.isVolatileQualified(), "tmp");
396      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
397                                        Dst.getVectorIdx(), "vecins");
398      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
399      return;
400    }
401
402    // If this is an update of extended vector elements, insert them as
403    // appropriate.
404    if (Dst.isExtVectorElt())
405      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
406
407    if (Dst.isBitfield())
408      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
409
410    if (Dst.isPropertyRef())
411      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
412
413    if (Dst.isKVCRef())
414      return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
415
416    assert(0 && "Unknown LValue type");
417  }
418
419  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
420    // load of a __weak object.
421    llvm::Value *LvalueDst = Dst.getAddress();
422    llvm::Value *src = Src.getScalarVal();
423    CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
424    return;
425  }
426
427  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
428    // load of a __strong object.
429    llvm::Value *LvalueDst = Dst.getAddress();
430    llvm::Value *src = Src.getScalarVal();
431#if 0
432    // FIXME. We cannot positively determine if we have an
433    // 'ivar' assignment, object assignment or an unknown
434    // assignment. For now, generate call to objc_assign_strongCast
435    // assignment which is a safe, but consevative assumption.
436    if (Dst.isObjCIvar())
437      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, LvalueDst);
438    else
439      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
440#endif
441    CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
442    return;
443  }
444
445  assert(Src.isScalar() && "Can't emit an agg store with this method");
446  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
447                    Dst.isVolatileQualified());
448}
449
450void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
451                                                     QualType Ty,
452                                                     llvm::Value **Result) {
453  unsigned StartBit = Dst.getBitfieldStartBit();
454  unsigned BitfieldSize = Dst.getBitfieldSize();
455  llvm::Value *Ptr = Dst.getBitfieldAddr();
456
457  const llvm::Type *EltTy =
458    cast<llvm::PointerType>(Ptr->getType())->getElementType();
459  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
460
461  // Get the new value, cast to the appropriate type and masked to
462  // exactly the size of the bit-field.
463  llvm::Value *SrcVal = Src.getScalarVal();
464  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
465  llvm::Constant *Mask =
466    llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
467  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
468
469  // Return the new value of the bit-field, if requested.
470  if (Result) {
471    // Cast back to the proper type for result.
472    const llvm::Type *SrcTy = SrcVal->getType();
473    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
474                                                  "bf.reload.val");
475
476    // Sign extend if necessary.
477    if (Dst.isBitfieldSigned()) {
478      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
479      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
480                                                      SrcTySize - BitfieldSize);
481      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
482                                    ExtraBits, "bf.reload.sext");
483    }
484
485    *Result = SrcTrunc;
486  }
487
488  // In some cases the bitfield may straddle two memory locations.
489  // Emit the low part first and check to see if the high needs to be
490  // done.
491  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
492  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
493                                           "bf.prev.low");
494
495  // Compute the mask for zero-ing the low part of this bitfield.
496  llvm::Constant *InvMask =
497    llvm::ConstantInt::get(~llvm::APInt::getBitsSet(EltTySize, StartBit,
498                                                    StartBit + LowBits));
499
500  // Compute the new low part as
501  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
502  // with the shift of NewVal implicitly stripping the high bits.
503  llvm::Value *NewLowVal =
504    Builder.CreateShl(NewVal, llvm::ConstantInt::get(EltTy, StartBit),
505                      "bf.value.lo");
506  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
507  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
508
509  // Write back.
510  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
511
512  // If the low part doesn't cover the bitfield emit a high part.
513  if (LowBits < BitfieldSize) {
514    unsigned HighBits = BitfieldSize - LowBits;
515    llvm::Value *HighPtr =
516      Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
517                        "bf.ptr.hi");
518    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
519                                              Dst.isVolatileQualified(),
520                                              "bf.prev.hi");
521
522    // Compute the mask for zero-ing the high part of this bitfield.
523    llvm::Constant *InvMask =
524      llvm::ConstantInt::get(~llvm::APInt::getLowBitsSet(EltTySize, HighBits));
525
526    // Compute the new high part as
527    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
528    // where the high bits of NewVal have already been cleared and the
529    // shift stripping the low bits.
530    llvm::Value *NewHighVal =
531      Builder.CreateLShr(NewVal, llvm::ConstantInt::get(EltTy, LowBits),
532                        "bf.value.high");
533    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
534    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
535
536    // Write back.
537    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
538  }
539}
540
541void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
542                                                        LValue Dst,
543                                                        QualType Ty) {
544  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
545}
546
547void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
548                                                   LValue Dst,
549                                                   QualType Ty) {
550  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
551}
552
553void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
554                                                               LValue Dst,
555                                                               QualType Ty) {
556  // This access turns into a read/modify/write of the vector.  Load the input
557  // value now.
558  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
559                                        Dst.isVolatileQualified(), "tmp");
560  const llvm::Constant *Elts = Dst.getExtVectorElts();
561
562  llvm::Value *SrcVal = Src.getScalarVal();
563
564  if (const VectorType *VTy = Ty->getAsVectorType()) {
565    unsigned NumSrcElts = VTy->getNumElements();
566    unsigned NumDstElts =
567       cast<llvm::VectorType>(Vec->getType())->getNumElements();
568    if (NumDstElts == NumSrcElts) {
569      // Use shuffle vector is the src and destination are the same number
570      // of elements
571      llvm::SmallVector<llvm::Constant*, 4> Mask;
572      for (unsigned i = 0; i != NumSrcElts; ++i) {
573        unsigned InIdx = getAccessedFieldNo(i, Elts);
574        Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
575      }
576
577      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
578      Vec = Builder.CreateShuffleVector(SrcVal,
579                                        llvm::UndefValue::get(Vec->getType()),
580                                        MaskV, "tmp");
581    }
582    else if (NumDstElts > NumSrcElts) {
583      // Extended the source vector to the same length and then shuffle it
584      // into the destination.
585      // FIXME: since we're shuffling with undef, can we just use the indices
586      //        into that?  This could be simpler.
587      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
588      unsigned i;
589      for (i = 0; i != NumSrcElts; ++i)
590        ExtMask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
591      for (; i != NumDstElts; ++i)
592        ExtMask.push_back(llvm::UndefValue::get(llvm::Type::Int32Ty));
593      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
594                                                        ExtMask.size());
595      llvm::Value *ExtSrcVal =
596        Builder.CreateShuffleVector(SrcVal,
597                                    llvm::UndefValue::get(SrcVal->getType()),
598                                    ExtMaskV, "tmp");
599      // build identity
600      llvm::SmallVector<llvm::Constant*, 4> Mask;
601      for (unsigned i = 0; i != NumDstElts; ++i) {
602        Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, i));
603      }
604      // modify when what gets shuffled in
605      for (unsigned i = 0; i != NumSrcElts; ++i) {
606        unsigned Idx = getAccessedFieldNo(i, Elts);
607        Mask[Idx] =llvm::ConstantInt::get(llvm::Type::Int32Ty, i+NumDstElts);
608      }
609      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
610      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
611    }
612    else {
613      // We should never shorten the vector
614      assert(0 && "unexpected shorten vector length");
615    }
616  } else {
617    // If the Src is a scalar (not a vector) it must be updating one element.
618    unsigned InIdx = getAccessedFieldNo(0, Elts);
619    llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
620    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
621  }
622
623  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
624}
625
626LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
627  const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
628
629  if (VD && (VD->isBlockVarDecl() || isa<ParmVarDecl>(VD) ||
630        isa<ImplicitParamDecl>(VD))) {
631    LValue LV;
632    if (VD->getStorageClass() == VarDecl::Extern) {
633      LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
634                            E->getType().getCVRQualifiers(),
635                            getContext().getObjCGCAttrKind(E->getType()));
636    }
637    else {
638      llvm::Value *V = LocalDeclMap[VD];
639      assert(V && "DeclRefExpr not entered in LocalDeclMap?");
640      // local variables do not get their gc attribute set.
641      QualType::GCAttrTypes attr = QualType::GCNone;
642      // local static?
643      if (!VD->hasLocalStorage())
644        attr = getContext().getObjCGCAttrKind(E->getType());
645      if (VD->getAttr<BlocksAttr>()) {
646        bool needsCopyDispose = BlockRequiresCopying(VD->getType());
647        const llvm::Type *PtrStructTy = V->getType();
648        const llvm::Type *Ty = PtrStructTy;
649        Ty = llvm::PointerType::get(Ty, 0);
650        V = Builder.CreateStructGEP(V, 1, "forwarding");
651        V = Builder.CreateBitCast(V, Ty);
652        V = Builder.CreateLoad(V, false);
653        V = Builder.CreateBitCast(V, PtrStructTy);
654        V = Builder.CreateStructGEP(V, needsCopyDispose*2 + 4, "x");
655      }
656      LV = LValue::MakeAddr(V, E->getType().getCVRQualifiers(), attr);
657    }
658    LValue::SetObjCNonGC(LV, VD->hasLocalStorage());
659    return LV;
660  } else if (VD && VD->isFileVarDecl()) {
661    LValue LV = LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
662                                 E->getType().getCVRQualifiers(),
663                                 getContext().getObjCGCAttrKind(E->getType()));
664    return LV;
665  } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) {
666    return LValue::MakeAddr(CGM.GetAddrOfFunction(FD),
667                            E->getType().getCVRQualifiers(),
668                            getContext().getObjCGCAttrKind(E->getType()));
669  }
670  else if (const ImplicitParamDecl *IPD =
671      dyn_cast<ImplicitParamDecl>(E->getDecl())) {
672    llvm::Value *V = LocalDeclMap[IPD];
673    assert(V && "BlockVarDecl not entered in LocalDeclMap?");
674    return LValue::MakeAddr(V, E->getType().getCVRQualifiers(),
675                            getContext().getObjCGCAttrKind(E->getType()));
676  }
677  assert(0 && "Unimp declref");
678  //an invalid LValue, but the assert will
679  //ensure that this point is never reached.
680  return LValue();
681}
682
683LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
684  return LValue::MakeAddr(GetAddrOfBlockDecl(E), 0);
685}
686
687LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
688  // __extension__ doesn't affect lvalue-ness.
689  if (E->getOpcode() == UnaryOperator::Extension)
690    return EmitLValue(E->getSubExpr());
691
692  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
693  switch (E->getOpcode()) {
694  default: assert(0 && "Unknown unary operator lvalue!");
695  case UnaryOperator::Deref:
696    {
697      QualType T =
698        E->getSubExpr()->getType()->getAsPointerType()->getPointeeType();
699      LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()),
700                                   ExprTy->getAsPointerType()->getPointeeType()
701                                      .getCVRQualifiers(),
702                                   getContext().getObjCGCAttrKind(T));
703     // We should not generate __weak write barrier on indirect reference
704     // of a pointer to object; as in void foo (__weak id *param); *param = 0;
705     // But, we continue to generate __strong write barrier on indirect write
706     // into a pointer to object.
707     if (getContext().getLangOptions().ObjC1 &&
708         getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
709         LV.isObjCWeak())
710       LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate());
711     return LV;
712    }
713  case UnaryOperator::Real:
714  case UnaryOperator::Imag:
715    LValue LV = EmitLValue(E->getSubExpr());
716    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
717    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
718                                                    Idx, "idx"),
719                            ExprTy.getCVRQualifiers());
720  }
721}
722
723LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
724  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E), 0);
725}
726
727LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
728  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E), 0);
729}
730
731
732LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
733  std::string GlobalVarName;
734
735  switch (Type) {
736  default:
737    assert(0 && "Invalid type");
738  case PredefinedExpr::Func:
739    GlobalVarName = "__func__.";
740    break;
741  case PredefinedExpr::Function:
742    GlobalVarName = "__FUNCTION__.";
743    break;
744  case PredefinedExpr::PrettyFunction:
745    // FIXME:: Demangle C++ method names
746    GlobalVarName = "__PRETTY_FUNCTION__.";
747    break;
748  }
749
750  std::string FunctionName;
751  if(const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurFuncDecl)) {
752    FunctionName = CGM.getMangledName(FD);
753  } else {
754    // Just get the mangled name.
755    FunctionName = CurFn->getName();
756  }
757
758  GlobalVarName += FunctionName;
759  llvm::Constant *C =
760    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
761  return LValue::MakeAddr(C, 0);
762}
763
764LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
765  switch (E->getIdentType()) {
766  default:
767    return EmitUnsupportedLValue(E, "predefined expression");
768  case PredefinedExpr::Func:
769  case PredefinedExpr::Function:
770  case PredefinedExpr::PrettyFunction:
771    return EmitPredefinedFunctionName(E->getIdentType());
772  }
773}
774
775LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
776  // The index must always be an integer, which is not an aggregate.  Emit it.
777  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
778
779  // If the base is a vector type, then we are forming a vector element lvalue
780  // with this subscript.
781  if (E->getBase()->getType()->isVectorType()) {
782    // Emit the vector as an lvalue to get its address.
783    LValue LHS = EmitLValue(E->getBase());
784    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
785    // FIXME: This should properly sign/zero/extend or truncate Idx to i32.
786    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
787      E->getBase()->getType().getCVRQualifiers());
788  }
789
790  // The base must be a pointer, which is not an aggregate.  Emit it.
791  llvm::Value *Base = EmitScalarExpr(E->getBase());
792
793  // Extend or truncate the index type to 32 or 64-bits.
794  QualType IdxTy  = E->getIdx()->getType();
795  bool IdxSigned = IdxTy->isSignedIntegerType();
796  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
797  if (IdxBitwidth != LLVMPointerWidth)
798    Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(LLVMPointerWidth),
799                                IdxSigned, "idxprom");
800
801  // We know that the pointer points to a type of the correct size, unless the
802  // size is a VLA.
803  if (const VariableArrayType *VAT =
804        getContext().getAsVariableArrayType(E->getType())) {
805    llvm::Value *VLASize = VLASizeMap[VAT];
806
807    Idx = Builder.CreateMul(Idx, VLASize);
808
809    QualType BaseType = getContext().getBaseElementType(VAT);
810
811    uint64_t BaseTypeSize = getContext().getTypeSize(BaseType) / 8;
812    Idx = Builder.CreateUDiv(Idx,
813                             llvm::ConstantInt::get(Idx->getType(),
814                                                    BaseTypeSize));
815  }
816
817  QualType T = E->getBase()->getType();
818  QualType ExprTy = getContext().getCanonicalType(T);
819  T = T->getAsPointerType()->getPointeeType();
820  LValue LV =
821           LValue::MakeAddr(Builder.CreateGEP(Base, Idx, "arrayidx"),
822           ExprTy->getAsPointerType()->getPointeeType().getCVRQualifiers(),
823           getContext().getObjCGCAttrKind(T));
824  if (getContext().getLangOptions().ObjC1 &&
825      getContext().getLangOptions().getGCMode() != LangOptions::NonGC)
826    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate());
827  return LV;
828}
829
830static
831llvm::Constant *GenerateConstantVector(llvm::SmallVector<unsigned, 4> &Elts) {
832  llvm::SmallVector<llvm::Constant *, 4> CElts;
833
834  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
835    CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, Elts[i]));
836
837  return llvm::ConstantVector::get(&CElts[0], CElts.size());
838}
839
840LValue CodeGenFunction::
841EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
842  // Emit the base vector as an l-value.
843  LValue Base;
844
845  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
846  if (!E->isArrow()) {
847    assert(E->getBase()->getType()->isVectorType());
848    Base = EmitLValue(E->getBase());
849  } else {
850    const PointerType *PT = E->getBase()->getType()->getAsPointerType();
851    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
852    Base = LValue::MakeAddr(Ptr, PT->getPointeeType().getCVRQualifiers());
853  }
854
855  // Encode the element access list into a vector of unsigned indices.
856  llvm::SmallVector<unsigned, 4> Indices;
857  E->getEncodedElementAccess(Indices);
858
859  if (Base.isSimple()) {
860    llvm::Constant *CV = GenerateConstantVector(Indices);
861    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
862                                    Base.getQualifiers());
863  }
864  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
865
866  llvm::Constant *BaseElts = Base.getExtVectorElts();
867  llvm::SmallVector<llvm::Constant *, 4> CElts;
868
869  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
870    if (isa<llvm::ConstantAggregateZero>(BaseElts))
871      CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
872    else
873      CElts.push_back(BaseElts->getOperand(Indices[i]));
874  }
875  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
876  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
877                                  Base.getQualifiers());
878}
879
880LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
881  bool isUnion = false;
882  bool isIvar = false;
883  bool isNonGC = false;
884  Expr *BaseExpr = E->getBase();
885  llvm::Value *BaseValue = NULL;
886  unsigned CVRQualifiers=0;
887
888  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
889  if (E->isArrow()) {
890    BaseValue = EmitScalarExpr(BaseExpr);
891    const PointerType *PTy =
892      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
893    if (PTy->getPointeeType()->isUnionType())
894      isUnion = true;
895    CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
896  } else if (isa<ObjCPropertyRefExpr>(BaseExpr) ||
897             isa<ObjCKVCRefExpr>(BaseExpr)) {
898    RValue RV = EmitObjCPropertyGet(BaseExpr);
899    BaseValue = RV.getAggregateAddr();
900    if (BaseExpr->getType()->isUnionType())
901      isUnion = true;
902    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
903  } else {
904    LValue BaseLV = EmitLValue(BaseExpr);
905    if (BaseLV.isObjCIvar())
906      isIvar = true;
907    if (BaseLV.isNonGC())
908      isNonGC = true;
909    // FIXME: this isn't right for bitfields.
910    BaseValue = BaseLV.getAddress();
911    if (BaseExpr->getType()->isUnionType())
912      isUnion = true;
913    CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
914  }
915
916  FieldDecl *Field = dyn_cast<FieldDecl>(E->getMemberDecl());
917  // FIXME: Handle non-field member expressions
918  assert(Field && "No code generation for non-field member references");
919  LValue MemExpLV = EmitLValueForField(BaseValue, Field, isUnion,
920                                       CVRQualifiers);
921  LValue::SetObjCIvar(MemExpLV, isIvar);
922  LValue::SetObjCNonGC(MemExpLV, isNonGC);
923  return MemExpLV;
924}
925
926LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
927                                              FieldDecl* Field,
928                                              unsigned CVRQualifiers) {
929   unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
930  // FIXME: CodeGenTypes should expose a method to get the appropriate
931  // type for FieldTy (the appropriate type is ABI-dependent).
932  const llvm::Type *FieldTy =
933    CGM.getTypes().ConvertTypeForMem(Field->getType());
934  const llvm::PointerType *BaseTy =
935  cast<llvm::PointerType>(BaseValue->getType());
936  unsigned AS = BaseTy->getAddressSpace();
937  BaseValue = Builder.CreateBitCast(BaseValue,
938                                    llvm::PointerType::get(FieldTy, AS),
939                                    "tmp");
940  llvm::Value *V = Builder.CreateGEP(BaseValue,
941                              llvm::ConstantInt::get(llvm::Type::Int32Ty, idx),
942                              "tmp");
943
944  CodeGenTypes::BitFieldInfo bitFieldInfo =
945    CGM.getTypes().getBitFieldInfo(Field);
946  return LValue::MakeBitfield(V, bitFieldInfo.Begin, bitFieldInfo.Size,
947                              Field->getType()->isSignedIntegerType(),
948                            Field->getType().getCVRQualifiers()|CVRQualifiers);
949}
950
951LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
952                                           FieldDecl* Field,
953                                           bool isUnion,
954                                           unsigned CVRQualifiers)
955{
956  if (Field->isBitField())
957    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
958
959  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
960  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
961
962  // Match union field type.
963  if (isUnion) {
964    const llvm::Type *FieldTy =
965      CGM.getTypes().ConvertTypeForMem(Field->getType());
966    const llvm::PointerType * BaseTy =
967      cast<llvm::PointerType>(BaseValue->getType());
968    unsigned AS = BaseTy->getAddressSpace();
969    V = Builder.CreateBitCast(V,
970                              llvm::PointerType::get(FieldTy, AS),
971                              "tmp");
972  }
973
974  QualType::GCAttrTypes attr = QualType::GCNone;
975  if (CGM.getLangOptions().ObjC1 &&
976      CGM.getLangOptions().getGCMode() != LangOptions::NonGC) {
977    QualType Ty = Field->getType();
978    attr = Ty.getObjCGCAttr();
979    if (attr != QualType::GCNone) {
980      // __weak attribute on a field is ignored.
981      if (attr == QualType::Weak)
982        attr = QualType::GCNone;
983    }
984    else if (getContext().isObjCObjectPointerType(Ty))
985      attr = QualType::Strong;
986  }
987  LValue LV =
988    LValue::MakeAddr(V,
989                     Field->getType().getCVRQualifiers()|CVRQualifiers,
990                     attr);
991  return LV;
992}
993
994LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
995  const llvm::Type *LTy = ConvertType(E->getType());
996  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
997
998  const Expr* InitExpr = E->getInitializer();
999  LValue Result = LValue::MakeAddr(DeclPtr, E->getType().getCVRQualifiers());
1000
1001  if (E->getType()->isComplexType()) {
1002    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1003  } else if (hasAggregateLLVMType(E->getType())) {
1004    EmitAnyExpr(InitExpr, DeclPtr, false);
1005  } else {
1006    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1007  }
1008
1009  return Result;
1010}
1011
1012/// EmitCastLValue - Casts are never lvalues.  If a cast is needed by the code
1013/// generator in an lvalue context, then it must mean that we need the address
1014/// of an aggregate in order to access one of its fields.  This can happen for
1015/// all the reasons that casts are permitted with aggregate result, including
1016/// noop aggregate casts, and cast from scalar to union.
1017LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1018  // If this is an aggregate-to-aggregate cast, just use the input's address as
1019  // the lvalue.
1020  if (getContext().hasSameUnqualifiedType(E->getType(),
1021                                          E->getSubExpr()->getType()))
1022    return EmitLValue(E->getSubExpr());
1023
1024  // Otherwise, we must have a cast from scalar to union.
1025  assert(E->getType()->isUnionType() && "Expected scalar-to-union cast");
1026
1027  // Casts are only lvalues when the source and destination types are the same.
1028  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1029  EmitAnyExpr(E->getSubExpr(), Temp, false);
1030
1031  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1032                          getContext().getObjCGCAttrKind(E->getType()));
1033}
1034
1035//===--------------------------------------------------------------------===//
1036//                             Expression Emission
1037//===--------------------------------------------------------------------===//
1038
1039
1040RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
1041  // Builtins never have block type.
1042  if (E->getCallee()->getType()->isBlockPointerType())
1043    return EmitBlockCallExpr(E);
1044
1045  const Decl *TargetDecl = 0;
1046  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1047    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1048      TargetDecl = DRE->getDecl();
1049      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1050        if (unsigned builtinID = FD->getBuiltinID(getContext()))
1051          return EmitBuiltinExpr(FD, builtinID, E);
1052    }
1053  }
1054
1055  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1056  return EmitCallExpr(Callee, E->getCallee()->getType(),
1057                      E->arg_begin(), E->arg_end(), TargetDecl);
1058}
1059
1060LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1061  // Can only get l-value for binary operator expressions which are a
1062  // simple assignment of aggregate type.
1063  if (E->getOpcode() != BinaryOperator::Assign)
1064    return EmitUnsupportedLValue(E, "binary l-value expression");
1065
1066  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1067  EmitAggExpr(E, Temp, false);
1068  // FIXME: Are these qualifiers correct?
1069  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers(),
1070                          getContext().getObjCGCAttrKind(E->getType()));
1071}
1072
1073LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1074  // Can only get l-value for call expression returning aggregate type
1075  RValue RV = EmitCallExpr(E);
1076  return LValue::MakeAddr(RV.getAggregateAddr(),
1077                          E->getType().getCVRQualifiers(),
1078                          getContext().getObjCGCAttrKind(E->getType()));
1079}
1080
1081LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1082  // FIXME: This shouldn't require another copy.
1083  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1084  EmitAggExpr(E, Temp, false);
1085  return LValue::MakeAddr(Temp, E->getType().getCVRQualifiers());
1086}
1087
1088LValue
1089CodeGenFunction::EmitCXXConditionDeclLValue(const CXXConditionDeclExpr *E) {
1090  EmitLocalBlockVarDecl(*E->getVarDecl());
1091  return EmitDeclRefLValue(E);
1092}
1093
1094LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1095  // Can only get l-value for message expression returning aggregate type
1096  RValue RV = EmitObjCMessageExpr(E);
1097  // FIXME: can this be volatile?
1098  return LValue::MakeAddr(RV.getAggregateAddr(),
1099                          E->getType().getCVRQualifiers(),
1100                          getContext().getObjCGCAttrKind(E->getType()));
1101}
1102
1103llvm::Value *CodeGenFunction::EmitIvarOffset(ObjCInterfaceDecl *Interface,
1104                                             const ObjCIvarDecl *Ivar) {
1105  // Objective-C objects are traditionally C structures with their layout
1106  // defined at compile-time.  In some implementations, their layout is not
1107  // defined until run time in order to allow instance variables to be added to
1108  // a class without recompiling all of the subclasses.  If this is the case
1109  // then the CGObjCRuntime subclass must return true to LateBoundIvars and
1110  // implement the lookup itself.
1111  if (CGM.getObjCRuntime().LateBoundIVars())
1112    assert(0 && "late-bound ivars are unsupported");
1113  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1114}
1115
1116LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1117                                          llvm::Value *BaseValue,
1118                                          const ObjCIvarDecl *Ivar,
1119                                          const FieldDecl *Field,
1120                                          unsigned CVRQualifiers) {
1121  // See comment in EmitIvarOffset.
1122  if (CGM.getObjCRuntime().LateBoundIVars())
1123    assert(0 && "late-bound ivars are unsupported");
1124
1125  LValue LV = CGM.getObjCRuntime().EmitObjCValueForIvar(*this,
1126                                                        ObjectTy,
1127                                                        BaseValue, Ivar, Field,
1128                                                        CVRQualifiers);
1129  return LV;
1130}
1131
1132LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1133  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1134  llvm::Value *BaseValue = 0;
1135  const Expr *BaseExpr = E->getBase();
1136  unsigned CVRQualifiers = 0;
1137  QualType ObjectTy;
1138  if (E->isArrow()) {
1139    BaseValue = EmitScalarExpr(BaseExpr);
1140    const PointerType *PTy =
1141      cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
1142    ObjectTy = PTy->getPointeeType();
1143    CVRQualifiers = ObjectTy.getCVRQualifiers();
1144  } else {
1145    LValue BaseLV = EmitLValue(BaseExpr);
1146    // FIXME: this isn't right for bitfields.
1147    BaseValue = BaseLV.getAddress();
1148    ObjectTy = BaseExpr->getType();
1149    CVRQualifiers = ObjectTy.getCVRQualifiers();
1150  }
1151
1152  return EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1153                           getContext().getFieldDecl(E), CVRQualifiers);
1154}
1155
1156LValue
1157CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1158  // This is a special l-value that just issues sends when we load or
1159  // store through it.
1160  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1161}
1162
1163LValue
1164CodeGenFunction::EmitObjCKVCRefLValue(const ObjCKVCRefExpr *E) {
1165  // This is a special l-value that just issues sends when we load or
1166  // store through it.
1167  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1168}
1169
1170LValue
1171CodeGenFunction::EmitObjCSuperExpr(const ObjCSuperExpr *E) {
1172  return EmitUnsupportedLValue(E, "use of super");
1173}
1174
1175RValue CodeGenFunction::EmitCallExpr(llvm::Value *Callee, QualType CalleeType,
1176                                     CallExpr::const_arg_iterator ArgBeg,
1177                                     CallExpr::const_arg_iterator ArgEnd,
1178                                     const Decl *TargetDecl) {
1179  // Get the actual function type. The callee type will always be a
1180  // pointer to function type or a block pointer type.
1181  QualType ResultType;
1182  if (const BlockPointerType *BPT = dyn_cast<BlockPointerType>(CalleeType)) {
1183    ResultType = BPT->getPointeeType()->getAsFunctionType()->getResultType();
1184  } else {
1185    assert(CalleeType->isFunctionPointerType() &&
1186           "Call must have function pointer type!");
1187    QualType FnType = CalleeType->getAsPointerType()->getPointeeType();
1188    ResultType = FnType->getAsFunctionType()->getResultType();
1189  }
1190
1191  CallArgList Args;
1192  for (CallExpr::const_arg_iterator I = ArgBeg; I != ArgEnd; ++I)
1193    Args.push_back(std::make_pair(EmitAnyExprToTemp(*I),
1194                                  I->getType()));
1195
1196  return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args),
1197                  Callee, Args, TargetDecl);
1198}
1199