CGExpr.cpp revision 7f2896406c8f14bf123578610043a919ba1a1c8a 
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 "CGRecordLayout.h"
18#include "CGObjCRuntime.h"
19#include "clang/AST/ASTContext.h"
20#include "clang/AST/DeclObjC.h"
21#include "llvm/Intrinsics.h"
22#include "clang/CodeGen/CodeGenOptions.h"
23#include "llvm/Target/TargetData.h"
24using namespace clang;
25using namespace CodeGen;
26
27//===--------------------------------------------------------------------===//
28//                        Miscellaneous Helper Methods
29//===--------------------------------------------------------------------===//
30
31/// CreateTempAlloca - This creates a alloca and inserts it into the entry
32/// block.
33llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
34                                                    const llvm::Twine &Name) {
35  if (!Builder.isNamePreserving())
36    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
37  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
38}
39
40llvm::Value *CodeGenFunction::CreateIRTemp(QualType Ty,
41                                           const llvm::Twine &Name) {
42  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
43  // FIXME: Should we prefer the preferred type alignment here?
44  CharUnits Align = getContext().getTypeAlignInChars(Ty);
45  Alloc->setAlignment(Align.getQuantity());
46  return Alloc;
47}
48
49llvm::Value *CodeGenFunction::CreateMemTemp(QualType Ty,
50                                            const llvm::Twine &Name) {
51  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
52  // FIXME: Should we prefer the preferred type alignment here?
53  CharUnits Align = getContext().getTypeAlignInChars(Ty);
54  Alloc->setAlignment(Align.getQuantity());
55  return Alloc;
56}
57
58/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
59/// expression and compare the result against zero, returning an Int1Ty value.
60llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
61  QualType BoolTy = getContext().BoolTy;
62  if (E->getType()->isMemberFunctionPointerType()) {
63    LValue LV = EmitAggExprToLValue(E);
64
65    // Get the pointer.
66    llvm::Value *FuncPtr = Builder.CreateStructGEP(LV.getAddress(), 0,
67                                                   "src.ptr");
68    FuncPtr = Builder.CreateLoad(FuncPtr);
69
70    llvm::Value *IsNotNull =
71      Builder.CreateICmpNE(FuncPtr,
72                            llvm::Constant::getNullValue(FuncPtr->getType()),
73                            "tobool");
74
75    return IsNotNull;
76  }
77  if (!E->getType()->isAnyComplexType())
78    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
79
80  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
81}
82
83/// EmitAnyExpr - Emit code to compute the specified expression which can have
84/// any type.  The result is returned as an RValue struct.  If this is an
85/// aggregate expression, the aggloc/agglocvolatile arguments indicate where the
86/// result should be returned.
87RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
88                                    bool IsAggLocVolatile, bool IgnoreResult,
89                                    bool IsInitializer) {
90  if (!hasAggregateLLVMType(E->getType()))
91    return RValue::get(EmitScalarExpr(E, IgnoreResult));
92  else if (E->getType()->isAnyComplexType())
93    return RValue::getComplex(EmitComplexExpr(E, false, false,
94                                              IgnoreResult, IgnoreResult));
95
96  EmitAggExpr(E, AggLoc, IsAggLocVolatile, IgnoreResult, IsInitializer);
97  return RValue::getAggregate(AggLoc, IsAggLocVolatile);
98}
99
100/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
101/// always be accessible even if no aggregate location is provided.
102RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E,
103                                          bool IsAggLocVolatile,
104                                          bool IsInitializer) {
105  llvm::Value *AggLoc = 0;
106
107  if (hasAggregateLLVMType(E->getType()) &&
108      !E->getType()->isAnyComplexType())
109    AggLoc = CreateMemTemp(E->getType(), "agg.tmp");
110  return EmitAnyExpr(E, AggLoc, IsAggLocVolatile, /*IgnoreResult=*/false,
111                     IsInitializer);
112}
113
114RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr* E,
115                                                   bool IsInitializer) {
116  bool ShouldDestroyTemporaries = false;
117  unsigned OldNumLiveTemporaries = 0;
118
119  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
120    E = DAE->getExpr();
121
122  if (const CXXExprWithTemporaries *TE = dyn_cast<CXXExprWithTemporaries>(E)) {
123    ShouldDestroyTemporaries = true;
124
125    // Keep track of the current cleanup stack depth.
126    OldNumLiveTemporaries = LiveTemporaries.size();
127
128    E = TE->getSubExpr();
129  }
130
131  RValue Val;
132  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
133    // Emit the expr as an lvalue.
134    LValue LV = EmitLValue(E);
135    if (LV.isSimple()) {
136      if (ShouldDestroyTemporaries) {
137        // Pop temporaries.
138        while (LiveTemporaries.size() > OldNumLiveTemporaries)
139          PopCXXTemporary();
140      }
141
142      return RValue::get(LV.getAddress());
143    }
144
145    Val = EmitLoadOfLValue(LV, E->getType());
146
147    if (ShouldDestroyTemporaries) {
148      // Pop temporaries.
149      while (LiveTemporaries.size() > OldNumLiveTemporaries)
150        PopCXXTemporary();
151    }
152  } else {
153    const CXXRecordDecl *BaseClassDecl = 0;
154    const CXXRecordDecl *DerivedClassDecl = 0;
155
156    if (const CastExpr *CE =
157          dyn_cast<CastExpr>(E->IgnoreParenNoopCasts(getContext()))) {
158      if (CE->getCastKind() == CastExpr::CK_DerivedToBase) {
159        E = CE->getSubExpr();
160
161        BaseClassDecl =
162          cast<CXXRecordDecl>(CE->getType()->getAs<RecordType>()->getDecl());
163        DerivedClassDecl =
164          cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
165      }
166    }
167
168    Val = EmitAnyExprToTemp(E, /*IsAggLocVolatile=*/false,
169                            IsInitializer);
170
171    if (ShouldDestroyTemporaries) {
172      // Pop temporaries.
173      while (LiveTemporaries.size() > OldNumLiveTemporaries)
174        PopCXXTemporary();
175    }
176
177    if (IsInitializer) {
178      // We might have to destroy the temporary variable.
179      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
180        if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
181          if (!ClassDecl->hasTrivialDestructor()) {
182            const CXXDestructorDecl *Dtor =
183              ClassDecl->getDestructor(getContext());
184
185            {
186              DelayedCleanupBlock Scope(*this);
187              EmitCXXDestructorCall(Dtor, Dtor_Complete,
188                                    Val.getAggregateAddr());
189
190              // Make sure to jump to the exit block.
191              EmitBranch(Scope.getCleanupExitBlock());
192            }
193            if (Exceptions) {
194              EHCleanupBlock Cleanup(*this);
195              EmitCXXDestructorCall(Dtor, Dtor_Complete,
196                                    Val.getAggregateAddr());
197            }
198          }
199        }
200      }
201    }
202
203    // Check if need to perform the derived-to-base cast.
204    if (BaseClassDecl) {
205      llvm::Value *Derived = Val.getAggregateAddr();
206      llvm::Value *Base =
207        GetAddressOfBaseClass(Derived, DerivedClassDecl, BaseClassDecl,
208                              /*NullCheckValue=*/false);
209      return RValue::get(Base);
210    }
211  }
212
213  if (Val.isAggregate()) {
214    Val = RValue::get(Val.getAggregateAddr());
215  } else {
216    // Create a temporary variable that we can bind the reference to.
217    llvm::Value *Temp = CreateMemTemp(E->getType(), "reftmp");
218    if (Val.isScalar())
219      EmitStoreOfScalar(Val.getScalarVal(), Temp, false, E->getType());
220    else
221      StoreComplexToAddr(Val.getComplexVal(), Temp, false);
222    Val = RValue::get(Temp);
223  }
224
225  return Val;
226}
227
228
229/// getAccessedFieldNo - Given an encoded value and a result number, return the
230/// input field number being accessed.
231unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
232                                             const llvm::Constant *Elts) {
233  if (isa<llvm::ConstantAggregateZero>(Elts))
234    return 0;
235
236  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
237}
238
239void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
240  if (!CatchUndefined)
241    return;
242
243  const llvm::IntegerType *Size_tTy
244    = llvm::IntegerType::get(VMContext, LLVMPointerWidth);
245  Address = Builder.CreateBitCast(Address, PtrToInt8Ty);
246
247  const llvm::Type *ResType[] = {
248    Size_tTy
249  };
250  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, ResType, 1);
251  const llvm::IntegerType *IntTy = cast<llvm::IntegerType>(
252    CGM.getTypes().ConvertType(CGM.getContext().IntTy));
253  // In time, people may want to control this and use a 1 here.
254  llvm::Value *Arg = llvm::ConstantInt::get(IntTy, 0);
255  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
256  llvm::BasicBlock *Cont = createBasicBlock();
257  llvm::BasicBlock *Check = createBasicBlock();
258  llvm::Value *NegativeOne = llvm::ConstantInt::get(Size_tTy, -1ULL);
259  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
260
261  EmitBlock(Check);
262  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
263                                        llvm::ConstantInt::get(Size_tTy, Size)),
264                       Cont, getTrapBB());
265  EmitBlock(Cont);
266}
267
268
269llvm::Value *CodeGenFunction::
270EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
271                        bool isInc, bool isPre) {
272  QualType ValTy = E->getSubExpr()->getType();
273  llvm::Value *InVal = EmitLoadOfLValue(LV, ValTy).getScalarVal();
274
275  int AmountVal = isInc ? 1 : -1;
276
277  if (ValTy->isPointerType() &&
278      ValTy->getAs<PointerType>()->isVariableArrayType()) {
279    // The amount of the addition/subtraction needs to account for the VLA size
280    ErrorUnsupported(E, "VLA pointer inc/dec");
281  }
282
283  llvm::Value *NextVal;
284  if (const llvm::PointerType *PT =
285      dyn_cast<llvm::PointerType>(InVal->getType())) {
286    llvm::Constant *Inc =
287    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), AmountVal);
288    if (!isa<llvm::FunctionType>(PT->getElementType())) {
289      QualType PTEE = ValTy->getPointeeType();
290      if (const ObjCInterfaceType *OIT =
291          dyn_cast<ObjCInterfaceType>(PTEE)) {
292        // Handle interface types, which are not represented with a concrete
293        // type.
294        int size = getContext().getTypeSize(OIT) / 8;
295        if (!isInc)
296          size = -size;
297        Inc = llvm::ConstantInt::get(Inc->getType(), size);
298        const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
299        InVal = Builder.CreateBitCast(InVal, i8Ty);
300        NextVal = Builder.CreateGEP(InVal, Inc, "add.ptr");
301        llvm::Value *lhs = LV.getAddress();
302        lhs = Builder.CreateBitCast(lhs, llvm::PointerType::getUnqual(i8Ty));
303        LV = LValue::MakeAddr(lhs, MakeQualifiers(ValTy));
304      } else
305        NextVal = Builder.CreateInBoundsGEP(InVal, Inc, "ptrincdec");
306    } else {
307      const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
308      NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp");
309      NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec");
310      NextVal = Builder.CreateBitCast(NextVal, InVal->getType());
311    }
312  } else if (InVal->getType() == llvm::Type::getInt1Ty(VMContext) && isInc) {
313    // Bool++ is an interesting case, due to promotion rules, we get:
314    // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 ->
315    // Bool = ((int)Bool+1) != 0
316    // An interesting aspect of this is that increment is always true.
317    // Decrement does not have this property.
318    NextVal = llvm::ConstantInt::getTrue(VMContext);
319  } else if (isa<llvm::IntegerType>(InVal->getType())) {
320    NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
321
322    // Signed integer overflow is undefined behavior.
323    if (ValTy->isSignedIntegerType())
324      NextVal = Builder.CreateNSWAdd(InVal, NextVal, isInc ? "inc" : "dec");
325    else
326      NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
327  } else {
328    // Add the inc/dec to the real part.
329    if (InVal->getType()->isFloatTy())
330      NextVal =
331      llvm::ConstantFP::get(VMContext,
332                            llvm::APFloat(static_cast<float>(AmountVal)));
333    else if (InVal->getType()->isDoubleTy())
334      NextVal =
335      llvm::ConstantFP::get(VMContext,
336                            llvm::APFloat(static_cast<double>(AmountVal)));
337    else {
338      llvm::APFloat F(static_cast<float>(AmountVal));
339      bool ignored;
340      F.convert(Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
341                &ignored);
342      NextVal = llvm::ConstantFP::get(VMContext, F);
343    }
344    NextVal = Builder.CreateFAdd(InVal, NextVal, isInc ? "inc" : "dec");
345  }
346
347  // Store the updated result through the lvalue.
348  if (LV.isBitField())
349    EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy, &NextVal);
350  else
351    EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy);
352
353  // If this is a postinc, return the value read from memory, otherwise use the
354  // updated value.
355  return isPre ? NextVal : InVal;
356}
357
358
359CodeGenFunction::ComplexPairTy CodeGenFunction::
360EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
361                         bool isInc, bool isPre) {
362  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
363                                            LV.isVolatileQualified());
364
365  llvm::Value *NextVal;
366  if (isa<llvm::IntegerType>(InVal.first->getType())) {
367    uint64_t AmountVal = isInc ? 1 : -1;
368    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
369
370    // Add the inc/dec to the real part.
371    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
372  } else {
373    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
374    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
375    if (!isInc)
376      FVal.changeSign();
377    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
378
379    // Add the inc/dec to the real part.
380    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
381  }
382
383  ComplexPairTy IncVal(NextVal, InVal.second);
384
385  // Store the updated result through the lvalue.
386  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
387
388  // If this is a postinc, return the value read from memory, otherwise use the
389  // updated value.
390  return isPre ? IncVal : InVal;
391}
392
393
394//===----------------------------------------------------------------------===//
395//                         LValue Expression Emission
396//===----------------------------------------------------------------------===//
397
398RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
399  if (Ty->isVoidType())
400    return RValue::get(0);
401
402  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
403    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
404    llvm::Value *U = llvm::UndefValue::get(EltTy);
405    return RValue::getComplex(std::make_pair(U, U));
406  }
407
408  if (hasAggregateLLVMType(Ty)) {
409    const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
410    return RValue::getAggregate(llvm::UndefValue::get(LTy));
411  }
412
413  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
414}
415
416RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
417                                              const char *Name) {
418  ErrorUnsupported(E, Name);
419  return GetUndefRValue(E->getType());
420}
421
422LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
423                                              const char *Name) {
424  ErrorUnsupported(E, Name);
425  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
426  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
427                          MakeQualifiers(E->getType()));
428}
429
430LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
431  LValue LV = EmitLValue(E);
432  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
433    EmitCheck(LV.getAddress(), getContext().getTypeSize(E->getType()) / 8);
434  return LV;
435}
436
437/// EmitLValue - Emit code to compute a designator that specifies the location
438/// of the expression.
439///
440/// This can return one of two things: a simple address or a bitfield reference.
441/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
442/// an LLVM pointer type.
443///
444/// If this returns a bitfield reference, nothing about the pointee type of the
445/// LLVM value is known: For example, it may not be a pointer to an integer.
446///
447/// If this returns a normal address, and if the lvalue's C type is fixed size,
448/// this method guarantees that the returned pointer type will point to an LLVM
449/// type of the same size of the lvalue's type.  If the lvalue has a variable
450/// length type, this is not possible.
451///
452LValue CodeGenFunction::EmitLValue(const Expr *E) {
453  switch (E->getStmtClass()) {
454  default: return EmitUnsupportedLValue(E, "l-value expression");
455
456  case Expr::ObjCIsaExprClass:
457    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
458  case Expr::BinaryOperatorClass:
459    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
460  case Expr::CallExprClass:
461  case Expr::CXXMemberCallExprClass:
462  case Expr::CXXOperatorCallExprClass:
463    return EmitCallExprLValue(cast<CallExpr>(E));
464  case Expr::VAArgExprClass:
465    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
466  case Expr::DeclRefExprClass:
467    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
468  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
469  case Expr::PredefinedExprClass:
470    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
471  case Expr::StringLiteralClass:
472    return EmitStringLiteralLValue(cast<StringLiteral>(E));
473  case Expr::ObjCEncodeExprClass:
474    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
475
476  case Expr::BlockDeclRefExprClass:
477    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
478
479  case Expr::CXXTemporaryObjectExprClass:
480  case Expr::CXXConstructExprClass:
481    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
482  case Expr::CXXBindTemporaryExprClass:
483    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
484  case Expr::CXXExprWithTemporariesClass:
485    return EmitCXXExprWithTemporariesLValue(cast<CXXExprWithTemporaries>(E));
486  case Expr::CXXZeroInitValueExprClass:
487    return EmitNullInitializationLValue(cast<CXXZeroInitValueExpr>(E));
488  case Expr::CXXDefaultArgExprClass:
489    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
490  case Expr::CXXTypeidExprClass:
491    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
492
493  case Expr::ObjCMessageExprClass:
494    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
495  case Expr::ObjCIvarRefExprClass:
496    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
497  case Expr::ObjCPropertyRefExprClass:
498    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
499  case Expr::ObjCImplicitSetterGetterRefExprClass:
500    return EmitObjCKVCRefLValue(cast<ObjCImplicitSetterGetterRefExpr>(E));
501  case Expr::ObjCSuperExprClass:
502    return EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
503
504  case Expr::StmtExprClass:
505    return EmitStmtExprLValue(cast<StmtExpr>(E));
506  case Expr::UnaryOperatorClass:
507    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
508  case Expr::ArraySubscriptExprClass:
509    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
510  case Expr::ExtVectorElementExprClass:
511    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
512  case Expr::MemberExprClass:
513    return EmitMemberExpr(cast<MemberExpr>(E));
514  case Expr::CompoundLiteralExprClass:
515    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
516  case Expr::ConditionalOperatorClass:
517    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
518  case Expr::ChooseExprClass:
519    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
520  case Expr::ImplicitCastExprClass:
521  case Expr::CStyleCastExprClass:
522  case Expr::CXXFunctionalCastExprClass:
523  case Expr::CXXStaticCastExprClass:
524  case Expr::CXXDynamicCastExprClass:
525  case Expr::CXXReinterpretCastExprClass:
526  case Expr::CXXConstCastExprClass:
527    return EmitCastLValue(cast<CastExpr>(E));
528  }
529}
530
531llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
532                                               QualType Ty) {
533  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
534  if (Volatile)
535    Load->setVolatile(true);
536
537  // Bool can have different representation in memory than in registers.
538  llvm::Value *V = Load;
539  if (Ty->isBooleanType())
540    if (V->getType() != llvm::Type::getInt1Ty(VMContext))
541      V = Builder.CreateTrunc(V, llvm::Type::getInt1Ty(VMContext), "tobool");
542
543  return V;
544}
545
546void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
547                                        bool Volatile, QualType Ty) {
548
549  if (Ty->isBooleanType()) {
550    // Bool can have different representation in memory than in registers.
551    const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
552    Value = Builder.CreateIntCast(Value, DstPtr->getElementType(), false);
553  }
554  Builder.CreateStore(Value, Addr, Volatile);
555}
556
557/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
558/// method emits the address of the lvalue, then loads the result as an rvalue,
559/// returning the rvalue.
560RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
561  if (LV.isObjCWeak()) {
562    // load of a __weak object.
563    llvm::Value *AddrWeakObj = LV.getAddress();
564    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
565                                                             AddrWeakObj));
566  }
567
568  if (LV.isSimple()) {
569    llvm::Value *Ptr = LV.getAddress();
570    const llvm::Type *EltTy =
571      cast<llvm::PointerType>(Ptr->getType())->getElementType();
572
573    // Simple scalar l-value.
574    //
575    // FIXME: We shouldn't have to use isSingleValueType here.
576    if (EltTy->isSingleValueType())
577      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
578                                          ExprType));
579
580    assert(ExprType->isFunctionType() && "Unknown scalar value");
581    return RValue::get(Ptr);
582  }
583
584  if (LV.isVectorElt()) {
585    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
586                                          LV.isVolatileQualified(), "tmp");
587    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
588                                                    "vecext"));
589  }
590
591  // If this is a reference to a subset of the elements of a vector, either
592  // shuffle the input or extract/insert them as appropriate.
593  if (LV.isExtVectorElt())
594    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
595
596  if (LV.isBitField())
597    return EmitLoadOfBitfieldLValue(LV, ExprType);
598
599  if (LV.isPropertyRef())
600    return EmitLoadOfPropertyRefLValue(LV, ExprType);
601
602  assert(LV.isKVCRef() && "Unknown LValue type!");
603  return EmitLoadOfKVCRefLValue(LV, ExprType);
604}
605
606static llvm::Value *getBitFieldAddr(LValue LV, CGBuilderTy &Builder) {
607  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
608
609  llvm::Value *BaseValue = LV.getBitFieldBaseAddr();
610  const llvm::PointerType *BaseTy =
611    cast<llvm::PointerType>(BaseValue->getType());
612
613  // Cast to the type of the access we will perform.
614  llvm::Value *V = Builder.CreateBitCast(
615    BaseValue, llvm::PointerType::get(Info.FieldTy, BaseTy->getAddressSpace()));
616
617  // Offset by the access index.
618  return Builder.CreateConstGEP1_32(V, Info.FieldNo);
619}
620
621RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
622                                                 QualType ExprType) {
623  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
624  unsigned StartBit = Info.Start;
625  unsigned BitfieldSize = Info.Size;
626  llvm::Value *Ptr = getBitFieldAddr(LV, Builder);
627
628  const llvm::Type *EltTy =
629    cast<llvm::PointerType>(Ptr->getType())->getElementType();
630  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
631
632  // In some cases the bitfield may straddle two memory locations.  Currently we
633  // load the entire bitfield, then do the magic to sign-extend it if
634  // necessary. This results in somewhat more code than necessary for the common
635  // case (one load), since two shifts accomplish both the masking and sign
636  // extension.
637  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
638  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
639
640  // Shift to proper location.
641  if (StartBit)
642    Val = Builder.CreateLShr(Val, StartBit, "bf.lo");
643
644  // Mask off unused bits.
645  llvm::Constant *LowMask = llvm::ConstantInt::get(VMContext,
646                                llvm::APInt::getLowBitsSet(EltTySize, LowBits));
647  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
648
649  // Fetch the high bits if necessary.
650  if (LowBits < BitfieldSize) {
651    unsigned HighBits = BitfieldSize - LowBits;
652    llvm::Value *HighPtr = Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
653                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
654    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
655                                              LV.isVolatileQualified(),
656                                              "tmp");
657
658    // Mask off unused bits.
659    llvm::Constant *HighMask = llvm::ConstantInt::get(VMContext,
660                               llvm::APInt::getLowBitsSet(EltTySize, HighBits));
661    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
662
663    // Shift to proper location and or in to bitfield value.
664    HighVal = Builder.CreateShl(HighVal, LowBits);
665    Val = Builder.CreateOr(Val, HighVal, "bf.val");
666  }
667
668  // Sign extend if necessary.
669  if (Info.IsSigned) {
670    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
671                                                    EltTySize - BitfieldSize);
672    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
673                             ExtraBits, "bf.val.sext");
674  }
675
676  // The bitfield type and the normal type differ when the storage sizes differ
677  // (currently just _Bool).
678  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
679
680  return RValue::get(Val);
681}
682
683RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
684                                                    QualType ExprType) {
685  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
686}
687
688RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
689                                               QualType ExprType) {
690  return EmitObjCPropertyGet(LV.getKVCRefExpr());
691}
692
693// If this is a reference to a subset of the elements of a vector, create an
694// appropriate shufflevector.
695RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
696                                                         QualType ExprType) {
697  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
698                                        LV.isVolatileQualified(), "tmp");
699
700  const llvm::Constant *Elts = LV.getExtVectorElts();
701
702  // If the result of the expression is a non-vector type, we must be extracting
703  // a single element.  Just codegen as an extractelement.
704  const VectorType *ExprVT = ExprType->getAs<VectorType>();
705  if (!ExprVT) {
706    unsigned InIdx = getAccessedFieldNo(0, Elts);
707    llvm::Value *Elt = llvm::ConstantInt::get(
708                                      llvm::Type::getInt32Ty(VMContext), InIdx);
709    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
710  }
711
712  // Always use shuffle vector to try to retain the original program structure
713  unsigned NumResultElts = ExprVT->getNumElements();
714
715  llvm::SmallVector<llvm::Constant*, 4> Mask;
716  for (unsigned i = 0; i != NumResultElts; ++i) {
717    unsigned InIdx = getAccessedFieldNo(i, Elts);
718    Mask.push_back(llvm::ConstantInt::get(
719                                     llvm::Type::getInt32Ty(VMContext), InIdx));
720  }
721
722  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
723  Vec = Builder.CreateShuffleVector(Vec,
724                                    llvm::UndefValue::get(Vec->getType()),
725                                    MaskV, "tmp");
726  return RValue::get(Vec);
727}
728
729
730
731/// EmitStoreThroughLValue - Store the specified rvalue into the specified
732/// lvalue, where both are guaranteed to the have the same type, and that type
733/// is 'Ty'.
734void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
735                                             QualType Ty) {
736  if (!Dst.isSimple()) {
737    if (Dst.isVectorElt()) {
738      // Read/modify/write the vector, inserting the new element.
739      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
740                                            Dst.isVolatileQualified(), "tmp");
741      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
742                                        Dst.getVectorIdx(), "vecins");
743      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
744      return;
745    }
746
747    // If this is an update of extended vector elements, insert them as
748    // appropriate.
749    if (Dst.isExtVectorElt())
750      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
751
752    if (Dst.isBitField())
753      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
754
755    if (Dst.isPropertyRef())
756      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
757
758    assert(Dst.isKVCRef() && "Unknown LValue type");
759    return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
760  }
761
762  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
763    // load of a __weak object.
764    llvm::Value *LvalueDst = Dst.getAddress();
765    llvm::Value *src = Src.getScalarVal();
766     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
767    return;
768  }
769
770  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
771    // load of a __strong object.
772    llvm::Value *LvalueDst = Dst.getAddress();
773    llvm::Value *src = Src.getScalarVal();
774    if (Dst.isObjCIvar()) {
775      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
776      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
777      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
778      llvm::Value *dst = RHS;
779      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
780      llvm::Value *LHS =
781        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
782      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
783      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
784                                              BytesBetween);
785    } else if (Dst.isGlobalObjCRef())
786      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
787    else
788      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
789    return;
790  }
791
792  assert(Src.isScalar() && "Can't emit an agg store with this method");
793  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
794                    Dst.isVolatileQualified(), Ty);
795}
796
797void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
798                                                     QualType Ty,
799                                                     llvm::Value **Result) {
800  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
801  unsigned StartBit = Info.Start;
802  unsigned BitfieldSize = Info.Size;
803  llvm::Value *Ptr = getBitFieldAddr(Dst, Builder);
804
805  const llvm::Type *EltTy =
806    cast<llvm::PointerType>(Ptr->getType())->getElementType();
807  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
808
809  // Get the new value, cast to the appropriate type and masked to exactly the
810  // size of the bit-field.
811  llvm::Value *SrcVal = Src.getScalarVal();
812  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
813  llvm::Constant *Mask = llvm::ConstantInt::get(VMContext,
814                           llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
815  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
816
817  // Return the new value of the bit-field, if requested.
818  if (Result) {
819    // Cast back to the proper type for result.
820    const llvm::Type *SrcTy = SrcVal->getType();
821    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
822                                                  "bf.reload.val");
823
824    // Sign extend if necessary.
825    if (Info.IsSigned) {
826      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
827      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
828                                                      SrcTySize - BitfieldSize);
829      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
830                                    ExtraBits, "bf.reload.sext");
831    }
832
833    *Result = SrcTrunc;
834  }
835
836  // In some cases the bitfield may straddle two memory locations.  Emit the low
837  // part first and check to see if the high needs to be done.
838  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
839  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
840                                           "bf.prev.low");
841
842  // Compute the mask for zero-ing the low part of this bitfield.
843  llvm::Constant *InvMask =
844    llvm::ConstantInt::get(VMContext,
845             ~llvm::APInt::getBitsSet(EltTySize, StartBit, StartBit + LowBits));
846
847  // Compute the new low part as
848  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
849  // with the shift of NewVal implicitly stripping the high bits.
850  llvm::Value *NewLowVal =
851    Builder.CreateShl(NewVal, StartBit, "bf.value.lo");
852  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
853  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
854
855  // Write back.
856  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
857
858  // If the low part doesn't cover the bitfield emit a high part.
859  if (LowBits < BitfieldSize) {
860    unsigned HighBits = BitfieldSize - LowBits;
861    llvm::Value *HighPtr =  Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
862                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
863    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
864                                              Dst.isVolatileQualified(),
865                                              "bf.prev.hi");
866
867    // Compute the mask for zero-ing the high part of this bitfield.
868    llvm::Constant *InvMask =
869      llvm::ConstantInt::get(VMContext, ~llvm::APInt::getLowBitsSet(EltTySize,
870                               HighBits));
871
872    // Compute the new high part as
873    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
874    // where the high bits of NewVal have already been cleared and the
875    // shift stripping the low bits.
876    llvm::Value *NewHighVal =
877      Builder.CreateLShr(NewVal, LowBits, "bf.value.high");
878    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
879    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
880
881    // Write back.
882    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
883  }
884}
885
886void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
887                                                        LValue Dst,
888                                                        QualType Ty) {
889  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
890}
891
892void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
893                                                   LValue Dst,
894                                                   QualType Ty) {
895  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
896}
897
898void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
899                                                               LValue Dst,
900                                                               QualType Ty) {
901  // This access turns into a read/modify/write of the vector.  Load the input
902  // value now.
903  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
904                                        Dst.isVolatileQualified(), "tmp");
905  const llvm::Constant *Elts = Dst.getExtVectorElts();
906
907  llvm::Value *SrcVal = Src.getScalarVal();
908
909  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
910    unsigned NumSrcElts = VTy->getNumElements();
911    unsigned NumDstElts =
912       cast<llvm::VectorType>(Vec->getType())->getNumElements();
913    if (NumDstElts == NumSrcElts) {
914      // Use shuffle vector is the src and destination are the same number of
915      // elements and restore the vector mask since it is on the side it will be
916      // stored.
917      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
918      for (unsigned i = 0; i != NumSrcElts; ++i) {
919        unsigned InIdx = getAccessedFieldNo(i, Elts);
920        Mask[InIdx] = llvm::ConstantInt::get(
921                                          llvm::Type::getInt32Ty(VMContext), i);
922      }
923
924      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
925      Vec = Builder.CreateShuffleVector(SrcVal,
926                                        llvm::UndefValue::get(Vec->getType()),
927                                        MaskV, "tmp");
928    } else if (NumDstElts > NumSrcElts) {
929      // Extended the source vector to the same length and then shuffle it
930      // into the destination.
931      // FIXME: since we're shuffling with undef, can we just use the indices
932      //        into that?  This could be simpler.
933      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
934      const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
935      unsigned i;
936      for (i = 0; i != NumSrcElts; ++i)
937        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
938      for (; i != NumDstElts; ++i)
939        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
940      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
941                                                        ExtMask.size());
942      llvm::Value *ExtSrcVal =
943        Builder.CreateShuffleVector(SrcVal,
944                                    llvm::UndefValue::get(SrcVal->getType()),
945                                    ExtMaskV, "tmp");
946      // build identity
947      llvm::SmallVector<llvm::Constant*, 4> Mask;
948      for (unsigned i = 0; i != NumDstElts; ++i)
949        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
950
951      // modify when what gets shuffled in
952      for (unsigned i = 0; i != NumSrcElts; ++i) {
953        unsigned Idx = getAccessedFieldNo(i, Elts);
954        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
955      }
956      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
957      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
958    } else {
959      // We should never shorten the vector
960      assert(0 && "unexpected shorten vector length");
961    }
962  } else {
963    // If the Src is a scalar (not a vector) it must be updating one element.
964    unsigned InIdx = getAccessedFieldNo(0, Elts);
965    const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
966    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
967    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
968  }
969
970  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
971}
972
973// setObjCGCLValueClass - sets class of he lvalue for the purpose of
974// generating write-barries API. It is currently a global, ivar,
975// or neither.
976static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
977                                 LValue &LV) {
978  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
979    return;
980
981  if (isa<ObjCIvarRefExpr>(E)) {
982    LV.SetObjCIvar(LV, true);
983    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
984    LV.setBaseIvarExp(Exp->getBase());
985    LV.SetObjCArray(LV, E->getType()->isArrayType());
986    return;
987  }
988
989  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
990    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
991      if ((VD->isBlockVarDecl() && !VD->hasLocalStorage()) ||
992          VD->isFileVarDecl())
993        LV.SetGlobalObjCRef(LV, true);
994    }
995    LV.SetObjCArray(LV, E->getType()->isArrayType());
996    return;
997  }
998
999  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1000    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1001    return;
1002  }
1003
1004  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1005    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1006    if (LV.isObjCIvar()) {
1007      // If cast is to a structure pointer, follow gcc's behavior and make it
1008      // a non-ivar write-barrier.
1009      QualType ExpTy = E->getType();
1010      if (ExpTy->isPointerType())
1011        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1012      if (ExpTy->isRecordType())
1013        LV.SetObjCIvar(LV, false);
1014    }
1015    return;
1016  }
1017  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1018    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1019    return;
1020  }
1021
1022  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1023    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1024    return;
1025  }
1026
1027  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1028    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1029    if (LV.isObjCIvar() && !LV.isObjCArray())
1030      // Using array syntax to assigning to what an ivar points to is not
1031      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1032      LV.SetObjCIvar(LV, false);
1033    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1034      // Using array syntax to assigning to what global points to is not
1035      // same as assigning to the global itself. {id *G;} G[i] = 0;
1036      LV.SetGlobalObjCRef(LV, false);
1037    return;
1038  }
1039
1040  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1041    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1042    // We don't know if member is an 'ivar', but this flag is looked at
1043    // only in the context of LV.isObjCIvar().
1044    LV.SetObjCArray(LV, E->getType()->isArrayType());
1045    return;
1046  }
1047}
1048
1049static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1050                                      const Expr *E, const VarDecl *VD) {
1051  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1052         "Var decl must have external storage or be a file var decl!");
1053
1054  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1055  if (VD->getType()->isReferenceType())
1056    V = CGF.Builder.CreateLoad(V, "tmp");
1057  LValue LV = LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1058  setObjCGCLValueClass(CGF.getContext(), E, LV);
1059  return LV;
1060}
1061
1062static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1063                                      const Expr *E, const FunctionDecl *FD) {
1064  llvm::Value* V = CGF.CGM.GetAddrOfFunction(FD);
1065  if (!FD->hasPrototype()) {
1066    if (const FunctionProtoType *Proto =
1067            FD->getType()->getAs<FunctionProtoType>()) {
1068      // Ugly case: for a K&R-style definition, the type of the definition
1069      // isn't the same as the type of a use.  Correct for this with a
1070      // bitcast.
1071      QualType NoProtoType =
1072          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1073      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1074      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1075    }
1076  }
1077  return LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1078}
1079
1080LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1081  const NamedDecl *ND = E->getDecl();
1082
1083  if (ND->hasAttr<WeakRefAttr>()) {
1084    const ValueDecl* VD = cast<ValueDecl>(ND);
1085    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1086
1087    Qualifiers Quals = MakeQualifiers(E->getType());
1088    LValue LV = LValue::MakeAddr(Aliasee, Quals);
1089
1090    return LV;
1091  }
1092
1093  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1094
1095    // Check if this is a global variable.
1096    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1097      return EmitGlobalVarDeclLValue(*this, E, VD);
1098
1099    bool NonGCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
1100
1101    llvm::Value *V = LocalDeclMap[VD];
1102    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1103
1104    Qualifiers Quals = MakeQualifiers(E->getType());
1105    // local variables do not get their gc attribute set.
1106    // local static?
1107    if (NonGCable) Quals.removeObjCGCAttr();
1108
1109    if (VD->hasAttr<BlocksAttr>()) {
1110      V = Builder.CreateStructGEP(V, 1, "forwarding");
1111      V = Builder.CreateLoad(V);
1112      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
1113                                  VD->getNameAsString());
1114    }
1115    if (VD->getType()->isReferenceType())
1116      V = Builder.CreateLoad(V, "tmp");
1117    LValue LV = LValue::MakeAddr(V, Quals);
1118    LValue::SetObjCNonGC(LV, NonGCable);
1119    setObjCGCLValueClass(getContext(), E, LV);
1120    return LV;
1121  }
1122
1123  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1124    return EmitFunctionDeclLValue(*this, E, FD);
1125
1126  // FIXME: the qualifier check does not seem sufficient here
1127  if (E->getQualifier()) {
1128    const FieldDecl *FD = cast<FieldDecl>(ND);
1129    llvm::Value *V = CGM.EmitPointerToDataMember(FD);
1130
1131    return LValue::MakeAddr(V, MakeQualifiers(FD->getType()));
1132  }
1133
1134  assert(false && "Unhandled DeclRefExpr");
1135
1136  // an invalid LValue, but the assert will
1137  // ensure that this point is never reached.
1138  return LValue();
1139}
1140
1141LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1142  return LValue::MakeAddr(GetAddrOfBlockDecl(E), MakeQualifiers(E->getType()));
1143}
1144
1145LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1146  // __extension__ doesn't affect lvalue-ness.
1147  if (E->getOpcode() == UnaryOperator::Extension)
1148    return EmitLValue(E->getSubExpr());
1149
1150  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1151  switch (E->getOpcode()) {
1152  default: assert(0 && "Unknown unary operator lvalue!");
1153  case UnaryOperator::Deref: {
1154    QualType T = E->getSubExpr()->getType()->getPointeeType();
1155    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1156
1157    Qualifiers Quals = MakeQualifiers(T);
1158    Quals.setAddressSpace(ExprTy.getAddressSpace());
1159
1160    LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()), Quals);
1161    // We should not generate __weak write barrier on indirect reference
1162    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1163    // But, we continue to generate __strong write barrier on indirect write
1164    // into a pointer to object.
1165    if (getContext().getLangOptions().ObjC1 &&
1166        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1167        LV.isObjCWeak())
1168      LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1169    return LV;
1170  }
1171  case UnaryOperator::Real:
1172  case UnaryOperator::Imag: {
1173    LValue LV = EmitLValue(E->getSubExpr());
1174    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
1175    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
1176                                                    Idx, "idx"),
1177                            MakeQualifiers(ExprTy));
1178  }
1179  case UnaryOperator::PreInc:
1180  case UnaryOperator::PreDec: {
1181    LValue LV = EmitLValue(E->getSubExpr());
1182    bool isInc = E->getOpcode() == UnaryOperator::PreInc;
1183
1184    if (E->getType()->isAnyComplexType())
1185      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1186    else
1187      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1188    return LV;
1189  }
1190  }
1191}
1192
1193LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1194  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E),
1195                          Qualifiers());
1196}
1197
1198LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1199  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1200                          Qualifiers());
1201}
1202
1203
1204LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
1205  std::string GlobalVarName;
1206
1207  switch (Type) {
1208  default: assert(0 && "Invalid type");
1209  case PredefinedExpr::Func:
1210    GlobalVarName = "__func__.";
1211    break;
1212  case PredefinedExpr::Function:
1213    GlobalVarName = "__FUNCTION__.";
1214    break;
1215  case PredefinedExpr::PrettyFunction:
1216    GlobalVarName = "__PRETTY_FUNCTION__.";
1217    break;
1218  }
1219
1220  llvm::StringRef FnName = CurFn->getName();
1221  if (FnName.startswith("\01"))
1222    FnName = FnName.substr(1);
1223  GlobalVarName += FnName;
1224
1225  std::string FunctionName =
1226    PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurCodeDecl);
1227
1228  llvm::Constant *C =
1229    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1230  return LValue::MakeAddr(C, Qualifiers());
1231}
1232
1233LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1234  switch (E->getIdentType()) {
1235  default:
1236    return EmitUnsupportedLValue(E, "predefined expression");
1237  case PredefinedExpr::Func:
1238  case PredefinedExpr::Function:
1239  case PredefinedExpr::PrettyFunction:
1240    return EmitPredefinedFunctionName(E->getIdentType());
1241  }
1242}
1243
1244llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1245  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1246
1247  // If we are not optimzing, don't collapse all calls to trap in the function
1248  // to the same call, that way, in the debugger they can see which operation
1249  // did in fact fail.  If we are optimizing, we collpase all call to trap down
1250  // to just one per function to save on codesize.
1251  if (GCO.OptimizationLevel
1252      && TrapBB)
1253    return TrapBB;
1254
1255  llvm::BasicBlock *Cont = 0;
1256  if (HaveInsertPoint()) {
1257    Cont = createBasicBlock("cont");
1258    EmitBranch(Cont);
1259  }
1260  TrapBB = createBasicBlock("trap");
1261  EmitBlock(TrapBB);
1262
1263  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1264  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1265  TrapCall->setDoesNotReturn();
1266  TrapCall->setDoesNotThrow();
1267  Builder.CreateUnreachable();
1268
1269  if (Cont)
1270    EmitBlock(Cont);
1271  return TrapBB;
1272}
1273
1274LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1275  // The index must always be an integer, which is not an aggregate.  Emit it.
1276  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1277  QualType IdxTy  = E->getIdx()->getType();
1278  bool IdxSigned = IdxTy->isSignedIntegerType();
1279
1280  // If the base is a vector type, then we are forming a vector element lvalue
1281  // with this subscript.
1282  if (E->getBase()->getType()->isVectorType()) {
1283    // Emit the vector as an lvalue to get its address.
1284    LValue LHS = EmitLValue(E->getBase());
1285    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1286    Idx = Builder.CreateIntCast(Idx,
1287                          llvm::Type::getInt32Ty(VMContext), IdxSigned, "vidx");
1288    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1289                                 E->getBase()->getType().getCVRQualifiers());
1290  }
1291
1292  // The base must be a pointer, which is not an aggregate.  Emit it.
1293  llvm::Value *Base = EmitScalarExpr(E->getBase());
1294
1295  // Extend or truncate the index type to 32 or 64-bits.
1296  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1297  if (IdxBitwidth != LLVMPointerWidth)
1298    Idx = Builder.CreateIntCast(Idx,
1299                            llvm::IntegerType::get(VMContext, LLVMPointerWidth),
1300                                IdxSigned, "idxprom");
1301
1302  // FIXME: As llvm implements the object size checking, this can come out.
1303  if (CatchUndefined) {
1304    if (const ImplicitCastExpr *ICE=dyn_cast<ImplicitCastExpr>(E->getBase())) {
1305      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1306        if (ICE->getCastKind() == CastExpr::CK_ArrayToPointerDecay) {
1307          if (const ConstantArrayType *CAT
1308              = getContext().getAsConstantArrayType(DRE->getType())) {
1309            llvm::APInt Size = CAT->getSize();
1310            llvm::BasicBlock *Cont = createBasicBlock("cont");
1311            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1312                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1313                                 Cont, getTrapBB());
1314            EmitBlock(Cont);
1315          }
1316        }
1317      }
1318    }
1319  }
1320
1321  // We know that the pointer points to a type of the correct size, unless the
1322  // size is a VLA or Objective-C interface.
1323  llvm::Value *Address = 0;
1324  if (const VariableArrayType *VAT =
1325        getContext().getAsVariableArrayType(E->getType())) {
1326    llvm::Value *VLASize = GetVLASize(VAT);
1327
1328    Idx = Builder.CreateMul(Idx, VLASize);
1329
1330    QualType BaseType = getContext().getBaseElementType(VAT);
1331
1332    CharUnits BaseTypeSize = getContext().getTypeSizeInChars(BaseType);
1333    Idx = Builder.CreateUDiv(Idx,
1334                             llvm::ConstantInt::get(Idx->getType(),
1335                                 BaseTypeSize.getQuantity()));
1336    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1337  } else if (const ObjCInterfaceType *OIT =
1338             dyn_cast<ObjCInterfaceType>(E->getType())) {
1339    llvm::Value *InterfaceSize =
1340      llvm::ConstantInt::get(Idx->getType(),
1341          getContext().getTypeSizeInChars(OIT).getQuantity());
1342
1343    Idx = Builder.CreateMul(Idx, InterfaceSize);
1344
1345    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1346    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1347                                Idx, "arrayidx");
1348    Address = Builder.CreateBitCast(Address, Base->getType());
1349  } else {
1350    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1351  }
1352
1353  QualType T = E->getBase()->getType()->getPointeeType();
1354  assert(!T.isNull() &&
1355         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1356
1357  Qualifiers Quals = MakeQualifiers(T);
1358  Quals.setAddressSpace(E->getBase()->getType().getAddressSpace());
1359
1360  LValue LV = LValue::MakeAddr(Address, Quals);
1361  if (getContext().getLangOptions().ObjC1 &&
1362      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1363    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1364    setObjCGCLValueClass(getContext(), E, LV);
1365  }
1366  return LV;
1367}
1368
1369static
1370llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1371                                       llvm::SmallVector<unsigned, 4> &Elts) {
1372  llvm::SmallVector<llvm::Constant*, 4> CElts;
1373
1374  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1375    CElts.push_back(llvm::ConstantInt::get(
1376                                   llvm::Type::getInt32Ty(VMContext), Elts[i]));
1377
1378  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1379}
1380
1381LValue CodeGenFunction::
1382EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1383  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1384
1385  // Emit the base vector as an l-value.
1386  LValue Base;
1387
1388  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1389  if (E->isArrow()) {
1390    // If it is a pointer to a vector, emit the address and form an lvalue with
1391    // it.
1392    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1393    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1394    Qualifiers Quals = MakeQualifiers(PT->getPointeeType());
1395    Quals.removeObjCGCAttr();
1396    Base = LValue::MakeAddr(Ptr, Quals);
1397  } else if (E->getBase()->isLvalue(getContext()) == Expr::LV_Valid) {
1398    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1399    // emit the base as an lvalue.
1400    assert(E->getBase()->getType()->isVectorType());
1401    Base = EmitLValue(E->getBase());
1402  } else {
1403    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1404    assert(E->getBase()->getType()->getAs<VectorType>() &&
1405           "Result must be a vector");
1406    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1407
1408    // Store the vector to memory (because LValue wants an address).
1409    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1410    Builder.CreateStore(Vec, VecMem);
1411    Base = LValue::MakeAddr(VecMem, Qualifiers());
1412  }
1413
1414  // Encode the element access list into a vector of unsigned indices.
1415  llvm::SmallVector<unsigned, 4> Indices;
1416  E->getEncodedElementAccess(Indices);
1417
1418  if (Base.isSimple()) {
1419    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1420    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1421                                    Base.getVRQualifiers());
1422  }
1423  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1424
1425  llvm::Constant *BaseElts = Base.getExtVectorElts();
1426  llvm::SmallVector<llvm::Constant *, 4> CElts;
1427
1428  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1429    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1430      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1431    else
1432      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1433  }
1434  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1435  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1436                                  Base.getVRQualifiers());
1437}
1438
1439LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1440  bool isNonGC = false;
1441  Expr *BaseExpr = E->getBase();
1442  llvm::Value *BaseValue = NULL;
1443  Qualifiers BaseQuals;
1444
1445  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1446  if (E->isArrow()) {
1447    BaseValue = EmitScalarExpr(BaseExpr);
1448    const PointerType *PTy =
1449      BaseExpr->getType()->getAs<PointerType>();
1450    BaseQuals = PTy->getPointeeType().getQualifiers();
1451  } else if (isa<ObjCPropertyRefExpr>(BaseExpr->IgnoreParens()) ||
1452             isa<ObjCImplicitSetterGetterRefExpr>(
1453               BaseExpr->IgnoreParens())) {
1454    RValue RV = EmitObjCPropertyGet(BaseExpr);
1455    BaseValue = RV.getAggregateAddr();
1456    BaseQuals = BaseExpr->getType().getQualifiers();
1457  } else {
1458    LValue BaseLV = EmitLValue(BaseExpr);
1459    if (BaseLV.isNonGC())
1460      isNonGC = true;
1461    // FIXME: this isn't right for bitfields.
1462    BaseValue = BaseLV.getAddress();
1463    QualType BaseTy = BaseExpr->getType();
1464    BaseQuals = BaseTy.getQualifiers();
1465  }
1466
1467  NamedDecl *ND = E->getMemberDecl();
1468  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1469    LValue LV = EmitLValueForField(BaseValue, Field,
1470                                   BaseQuals.getCVRQualifiers());
1471    LValue::SetObjCNonGC(LV, isNonGC);
1472    setObjCGCLValueClass(getContext(), E, LV);
1473    return LV;
1474  }
1475
1476  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1477    return EmitGlobalVarDeclLValue(*this, E, VD);
1478
1479  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1480    return EmitFunctionDeclLValue(*this, E, FD);
1481
1482  assert(false && "Unhandled member declaration!");
1483  return LValue();
1484}
1485
1486LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
1487                                              const FieldDecl* Field,
1488                                              unsigned CVRQualifiers) {
1489  const CGRecordLayout &RL =
1490    CGM.getTypes().getCGRecordLayout(Field->getParent());
1491  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1492  return LValue::MakeBitfield(BaseValue, Info,
1493                             Field->getType().getCVRQualifiers()|CVRQualifiers);
1494}
1495
1496LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
1497                                           const FieldDecl* Field,
1498                                           unsigned CVRQualifiers) {
1499  if (Field->isBitField())
1500    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1501
1502  const CGRecordLayout &RL =
1503    CGM.getTypes().getCGRecordLayout(Field->getParent());
1504  unsigned idx = RL.getLLVMFieldNo(Field);
1505  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1506
1507  // Match union field type.
1508  if (Field->getParent()->isUnion()) {
1509    const llvm::Type *FieldTy =
1510      CGM.getTypes().ConvertTypeForMem(Field->getType());
1511    const llvm::PointerType * BaseTy =
1512      cast<llvm::PointerType>(BaseValue->getType());
1513    unsigned AS = BaseTy->getAddressSpace();
1514    V = Builder.CreateBitCast(V,
1515                              llvm::PointerType::get(FieldTy, AS),
1516                              "tmp");
1517  }
1518  if (Field->getType()->isReferenceType())
1519    V = Builder.CreateLoad(V, "tmp");
1520
1521  Qualifiers Quals = MakeQualifiers(Field->getType());
1522  Quals.addCVRQualifiers(CVRQualifiers);
1523  // __weak attribute on a field is ignored.
1524  if (Quals.getObjCGCAttr() == Qualifiers::Weak)
1525    Quals.removeObjCGCAttr();
1526
1527  return LValue::MakeAddr(V, Quals);
1528}
1529
1530LValue
1531CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value* BaseValue,
1532                                                  const FieldDecl* Field,
1533                                                  unsigned CVRQualifiers) {
1534  QualType FieldType = Field->getType();
1535
1536  if (!FieldType->isReferenceType())
1537    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1538
1539  const CGRecordLayout &RL =
1540    CGM.getTypes().getCGRecordLayout(Field->getParent());
1541  unsigned idx = RL.getLLVMFieldNo(Field);
1542  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1543
1544  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1545
1546  return LValue::MakeAddr(V, MakeQualifiers(FieldType));
1547}
1548
1549LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1550  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1551  const Expr* InitExpr = E->getInitializer();
1552  LValue Result = LValue::MakeAddr(DeclPtr, MakeQualifiers(E->getType()));
1553
1554  if (E->getType()->isComplexType())
1555    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1556  else if (hasAggregateLLVMType(E->getType()))
1557    EmitAnyExpr(InitExpr, DeclPtr, false);
1558  else
1559    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1560
1561  return Result;
1562}
1563
1564LValue
1565CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator* E) {
1566  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
1567    if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1568      Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1569      if (Live)
1570        return EmitLValue(Live);
1571    }
1572
1573    if (!E->getLHS())
1574      return EmitUnsupportedLValue(E, "conditional operator with missing LHS");
1575
1576    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1577    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1578    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1579
1580    EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1581
1582    // Any temporaries created here are conditional.
1583    BeginConditionalBranch();
1584    EmitBlock(LHSBlock);
1585    LValue LHS = EmitLValue(E->getLHS());
1586    EndConditionalBranch();
1587
1588    if (!LHS.isSimple())
1589      return EmitUnsupportedLValue(E, "conditional operator");
1590
1591    // FIXME: We shouldn't need an alloca for this.
1592    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1593    Builder.CreateStore(LHS.getAddress(), Temp);
1594    EmitBranch(ContBlock);
1595
1596    // Any temporaries created here are conditional.
1597    BeginConditionalBranch();
1598    EmitBlock(RHSBlock);
1599    LValue RHS = EmitLValue(E->getRHS());
1600    EndConditionalBranch();
1601    if (!RHS.isSimple())
1602      return EmitUnsupportedLValue(E, "conditional operator");
1603
1604    Builder.CreateStore(RHS.getAddress(), Temp);
1605    EmitBranch(ContBlock);
1606
1607    EmitBlock(ContBlock);
1608
1609    Temp = Builder.CreateLoad(Temp, "lv");
1610    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1611  }
1612
1613  // ?: here should be an aggregate.
1614  assert((hasAggregateLLVMType(E->getType()) &&
1615          !E->getType()->isAnyComplexType()) &&
1616         "Unexpected conditional operator!");
1617
1618  return EmitAggExprToLValue(E);
1619}
1620
1621/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1622/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1623/// otherwise if a cast is needed by the code generator in an lvalue context,
1624/// then it must mean that we need the address of an aggregate in order to
1625/// access one of its fields.  This can happen for all the reasons that casts
1626/// are permitted with aggregate result, including noop aggregate casts, and
1627/// cast from scalar to union.
1628LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1629  switch (E->getCastKind()) {
1630  default:
1631    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1632
1633  case CastExpr::CK_Dynamic: {
1634    LValue LV = EmitLValue(E->getSubExpr());
1635    llvm::Value *V = LV.getAddress();
1636    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1637    return LValue::MakeAddr(EmitDynamicCast(V, DCE),
1638                            MakeQualifiers(E->getType()));
1639  }
1640
1641  case CastExpr::CK_NoOp:
1642  case CastExpr::CK_ConstructorConversion:
1643  case CastExpr::CK_UserDefinedConversion:
1644  case CastExpr::CK_AnyPointerToObjCPointerCast:
1645    return EmitLValue(E->getSubExpr());
1646
1647  case CastExpr::CK_UncheckedDerivedToBase:
1648  case CastExpr::CK_DerivedToBase: {
1649    const RecordType *DerivedClassTy =
1650      E->getSubExpr()->getType()->getAs<RecordType>();
1651    CXXRecordDecl *DerivedClassDecl =
1652      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1653
1654    const RecordType *BaseClassTy = E->getType()->getAs<RecordType>();
1655    CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseClassTy->getDecl());
1656
1657    LValue LV = EmitLValue(E->getSubExpr());
1658
1659    // Perform the derived-to-base conversion
1660    llvm::Value *Base =
1661      GetAddressOfBaseClass(LV.getAddress(), DerivedClassDecl,
1662                            BaseClassDecl, /*NullCheckValue=*/false);
1663
1664    return LValue::MakeAddr(Base, MakeQualifiers(E->getType()));
1665  }
1666  case CastExpr::CK_ToUnion:
1667    return EmitAggExprToLValue(E);
1668  case CastExpr::CK_BaseToDerived: {
1669    const RecordType *BaseClassTy =
1670      E->getSubExpr()->getType()->getAs<RecordType>();
1671    CXXRecordDecl *BaseClassDecl =
1672      cast<CXXRecordDecl>(BaseClassTy->getDecl());
1673
1674    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1675    CXXRecordDecl *DerivedClassDecl =
1676      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1677
1678    LValue LV = EmitLValue(E->getSubExpr());
1679
1680    // Perform the base-to-derived conversion
1681    llvm::Value *Derived =
1682      GetAddressOfDerivedClass(LV.getAddress(), BaseClassDecl,
1683                               DerivedClassDecl, /*NullCheckValue=*/false);
1684
1685    return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
1686  }
1687  case CastExpr::CK_BitCast: {
1688    // This must be a reinterpret_cast (or c-style equivalent).
1689    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1690
1691    LValue LV = EmitLValue(E->getSubExpr());
1692    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1693                                           ConvertType(CE->getTypeAsWritten()));
1694    return LValue::MakeAddr(V, MakeQualifiers(E->getType()));
1695  }
1696  }
1697}
1698
1699LValue CodeGenFunction::EmitNullInitializationLValue(
1700                                              const CXXZeroInitValueExpr *E) {
1701  QualType Ty = E->getType();
1702  LValue LV = LValue::MakeAddr(CreateMemTemp(Ty), MakeQualifiers(Ty));
1703  EmitMemSetToZero(LV.getAddress(), Ty);
1704  return LV;
1705}
1706
1707//===--------------------------------------------------------------------===//
1708//                             Expression Emission
1709//===--------------------------------------------------------------------===//
1710
1711
1712RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1713                                     ReturnValueSlot ReturnValue) {
1714  // Builtins never have block type.
1715  if (E->getCallee()->getType()->isBlockPointerType())
1716    return EmitBlockCallExpr(E, ReturnValue);
1717
1718  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1719    return EmitCXXMemberCallExpr(CE, ReturnValue);
1720
1721  const Decl *TargetDecl = 0;
1722  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1723    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1724      TargetDecl = DRE->getDecl();
1725      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1726        if (unsigned builtinID = FD->getBuiltinID())
1727          return EmitBuiltinExpr(FD, builtinID, E);
1728    }
1729  }
1730
1731  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1732    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1733      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1734
1735  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1736    // C++ [expr.pseudo]p1:
1737    //   The result shall only be used as the operand for the function call
1738    //   operator (), and the result of such a call has type void. The only
1739    //   effect is the evaluation of the postfix-expression before the dot or
1740    //   arrow.
1741    EmitScalarExpr(E->getCallee());
1742    return RValue::get(0);
1743  }
1744
1745  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1746  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1747                  E->arg_begin(), E->arg_end(), TargetDecl);
1748}
1749
1750LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1751  // Comma expressions just emit their LHS then their RHS as an l-value.
1752  if (E->getOpcode() == BinaryOperator::Comma) {
1753    EmitAnyExpr(E->getLHS());
1754    EnsureInsertPoint();
1755    return EmitLValue(E->getRHS());
1756  }
1757
1758  if (E->getOpcode() == BinaryOperator::PtrMemD ||
1759      E->getOpcode() == BinaryOperator::PtrMemI)
1760    return EmitPointerToDataMemberBinaryExpr(E);
1761
1762  // Can only get l-value for binary operator expressions which are a
1763  // simple assignment of aggregate type.
1764  if (E->getOpcode() != BinaryOperator::Assign)
1765    return EmitUnsupportedLValue(E, "binary l-value expression");
1766
1767  if (!hasAggregateLLVMType(E->getType())) {
1768    // Emit the LHS as an l-value.
1769    LValue LV = EmitLValue(E->getLHS());
1770
1771    llvm::Value *RHS = EmitScalarExpr(E->getRHS());
1772    EmitStoreOfScalar(RHS, LV.getAddress(), LV.isVolatileQualified(),
1773                      E->getType());
1774    return LV;
1775  }
1776
1777  return EmitAggExprToLValue(E);
1778}
1779
1780LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1781  RValue RV = EmitCallExpr(E);
1782
1783  if (!RV.isScalar())
1784    return LValue::MakeAddr(RV.getAggregateAddr(),MakeQualifiers(E->getType()));
1785
1786  assert(E->getCallReturnType()->isReferenceType() &&
1787         "Can't have a scalar return unless the return type is a "
1788         "reference type!");
1789
1790  return LValue::MakeAddr(RV.getScalarVal(), MakeQualifiers(E->getType()));
1791}
1792
1793LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1794  // FIXME: This shouldn't require another copy.
1795  return EmitAggExprToLValue(E);
1796}
1797
1798LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1799  llvm::Value *Temp = CreateMemTemp(E->getType(), "tmp");
1800  EmitCXXConstructExpr(Temp, E);
1801  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1802}
1803
1804LValue
1805CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1806  llvm::Value *Temp = EmitCXXTypeidExpr(E);
1807  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1808}
1809
1810LValue
1811CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1812  LValue LV = EmitLValue(E->getSubExpr());
1813  PushCXXTemporary(E->getTemporary(), LV.getAddress());
1814  return LV;
1815}
1816
1817LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1818  // Can only get l-value for message expression returning aggregate type
1819  RValue RV = EmitObjCMessageExpr(E);
1820  // FIXME: can this be volatile?
1821  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1822}
1823
1824llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1825                                             const ObjCIvarDecl *Ivar) {
1826  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1827}
1828
1829LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1830                                          llvm::Value *BaseValue,
1831                                          const ObjCIvarDecl *Ivar,
1832                                          unsigned CVRQualifiers) {
1833  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1834                                                   Ivar, CVRQualifiers);
1835}
1836
1837LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1838  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1839  llvm::Value *BaseValue = 0;
1840  const Expr *BaseExpr = E->getBase();
1841  Qualifiers BaseQuals;
1842  QualType ObjectTy;
1843  if (E->isArrow()) {
1844    BaseValue = EmitScalarExpr(BaseExpr);
1845    ObjectTy = BaseExpr->getType()->getPointeeType();
1846    BaseQuals = ObjectTy.getQualifiers();
1847  } else {
1848    LValue BaseLV = EmitLValue(BaseExpr);
1849    // FIXME: this isn't right for bitfields.
1850    BaseValue = BaseLV.getAddress();
1851    ObjectTy = BaseExpr->getType();
1852    BaseQuals = ObjectTy.getQualifiers();
1853  }
1854
1855  LValue LV =
1856    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1857                      BaseQuals.getCVRQualifiers());
1858  setObjCGCLValueClass(getContext(), E, LV);
1859  return LV;
1860}
1861
1862LValue
1863CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1864  // This is a special l-value that just issues sends when we load or store
1865  // through it.
1866  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1867}
1868
1869LValue CodeGenFunction::EmitObjCKVCRefLValue(
1870                                const ObjCImplicitSetterGetterRefExpr *E) {
1871  // This is a special l-value that just issues sends when we load or store
1872  // through it.
1873  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1874}
1875
1876LValue CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1877  return EmitUnsupportedLValue(E, "use of super");
1878}
1879
1880LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1881  // Can only get l-value for message expression returning aggregate type
1882  RValue RV = EmitAnyExprToTemp(E);
1883  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1884}
1885
1886RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
1887                                 ReturnValueSlot ReturnValue,
1888                                 CallExpr::const_arg_iterator ArgBeg,
1889                                 CallExpr::const_arg_iterator ArgEnd,
1890                                 const Decl *TargetDecl) {
1891  // Get the actual function type. The callee type will always be a pointer to
1892  // function type or a block pointer type.
1893  assert(CalleeType->isFunctionPointerType() &&
1894         "Call must have function pointer type!");
1895
1896  CalleeType = getContext().getCanonicalType(CalleeType);
1897
1898  const FunctionType *FnType
1899    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
1900  QualType ResultType = FnType->getResultType();
1901
1902  CallArgList Args;
1903  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
1904
1905  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
1906                  Callee, ReturnValue, Args, TargetDecl);
1907}
1908
1909LValue CodeGenFunction::
1910EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
1911  llvm::Value *BaseV;
1912  if (E->getOpcode() == BinaryOperator::PtrMemI)
1913    BaseV = EmitScalarExpr(E->getLHS());
1914  else
1915    BaseV = EmitLValue(E->getLHS()).getAddress();
1916  const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(getLLVMContext());
1917  BaseV = Builder.CreateBitCast(BaseV, i8Ty);
1918  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
1919  llvm::Value *AddV = Builder.CreateInBoundsGEP(BaseV, OffsetV, "add.ptr");
1920
1921  QualType Ty = E->getRHS()->getType();
1922  Ty = Ty->getAs<MemberPointerType>()->getPointeeType();
1923
1924  const llvm::Type *PType = ConvertType(getContext().getPointerType(Ty));
1925  AddV = Builder.CreateBitCast(AddV, PType);
1926  return LValue::MakeAddr(AddV, MakeQualifiers(Ty));
1927}
1928
1929