CGExpr.cpp revision e86bcf0d9ea62cc75e545787896083f8a6bc81a1 
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/Intrinsics.h"
21#include "clang/CodeGen/CodeGenOptions.h"
22#include "llvm/Target/TargetData.h"
23using namespace clang;
24using namespace CodeGen;
25
26//===--------------------------------------------------------------------===//
27//                        Miscellaneous Helper Methods
28//===--------------------------------------------------------------------===//
29
30/// CreateTempAlloca - This creates a alloca and inserts it into the entry
31/// block.
32llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
33                                                    const llvm::Twine &Name) {
34  if (!Builder.isNamePreserving())
35    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
36  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
37}
38
39/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
40/// expression and compare the result against zero, returning an Int1Ty value.
41llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
42  QualType BoolTy = getContext().BoolTy;
43  if (E->getType()->isMemberFunctionPointerType()) {
44    LValue LV = EmitAggExprToLValue(E);
45
46    // Get the pointer.
47    llvm::Value *FuncPtr = Builder.CreateStructGEP(LV.getAddress(), 0,
48                                                   "src.ptr");
49    FuncPtr = Builder.CreateLoad(FuncPtr);
50
51    llvm::Value *IsNotNull =
52      Builder.CreateICmpNE(FuncPtr,
53                            llvm::Constant::getNullValue(FuncPtr->getType()),
54                            "tobool");
55
56    return IsNotNull;
57  }
58  if (!E->getType()->isAnyComplexType())
59    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
60
61  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
62}
63
64/// EmitAnyExpr - Emit code to compute the specified expression which can have
65/// any type.  The result is returned as an RValue struct.  If this is an
66/// aggregate expression, the aggloc/agglocvolatile arguments indicate where the
67/// result should be returned.
68RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
69                                    bool IsAggLocVolatile, bool IgnoreResult,
70                                    bool IsInitializer) {
71  if (!hasAggregateLLVMType(E->getType()))
72    return RValue::get(EmitScalarExpr(E, IgnoreResult));
73  else if (E->getType()->isAnyComplexType())
74    return RValue::getComplex(EmitComplexExpr(E, false, false,
75                                              IgnoreResult, IgnoreResult));
76
77  EmitAggExpr(E, AggLoc, IsAggLocVolatile, IgnoreResult, IsInitializer);
78  return RValue::getAggregate(AggLoc, IsAggLocVolatile);
79}
80
81/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
82/// always be accessible even if no aggregate location is provided.
83RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E,
84                                          bool IsAggLocVolatile,
85                                          bool IsInitializer) {
86  llvm::Value *AggLoc = 0;
87
88  if (hasAggregateLLVMType(E->getType()) &&
89      !E->getType()->isAnyComplexType())
90    AggLoc = CreateTempAlloca(ConvertTypeForMem(E->getType()), "agg.tmp");
91  return EmitAnyExpr(E, AggLoc, IsAggLocVolatile, /*IgnoreResult=*/false,
92                     IsInitializer);
93}
94
95RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr* E,
96                                                   bool IsInitializer) {
97  bool ShouldDestroyTemporaries = false;
98  unsigned OldNumLiveTemporaries = 0;
99
100  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
101    E = DAE->getExpr();
102
103  if (const CXXExprWithTemporaries *TE = dyn_cast<CXXExprWithTemporaries>(E)) {
104    ShouldDestroyTemporaries = true;
105
106    // Keep track of the current cleanup stack depth.
107    OldNumLiveTemporaries = LiveTemporaries.size();
108
109    E = TE->getSubExpr();
110  }
111
112  RValue Val;
113  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
114    // Emit the expr as an lvalue.
115    LValue LV = EmitLValue(E);
116    if (LV.isSimple()) {
117      if (ShouldDestroyTemporaries) {
118        // Pop temporaries.
119        while (LiveTemporaries.size() > OldNumLiveTemporaries)
120          PopCXXTemporary();
121      }
122
123      return RValue::get(LV.getAddress());
124    }
125
126    Val = EmitLoadOfLValue(LV, E->getType());
127
128    if (ShouldDestroyTemporaries) {
129      // Pop temporaries.
130      while (LiveTemporaries.size() > OldNumLiveTemporaries)
131        PopCXXTemporary();
132    }
133  } else {
134    const CXXRecordDecl *BaseClassDecl = 0;
135    const CXXRecordDecl *DerivedClassDecl = 0;
136
137    if (const CastExpr *CE =
138          dyn_cast<CastExpr>(E->IgnoreParenNoopCasts(getContext()))) {
139      if (CE->getCastKind() == CastExpr::CK_DerivedToBase) {
140        E = CE->getSubExpr();
141
142        BaseClassDecl =
143          cast<CXXRecordDecl>(CE->getType()->getAs<RecordType>()->getDecl());
144        DerivedClassDecl =
145          cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
146      }
147    }
148
149    Val = EmitAnyExprToTemp(E, /*IsAggLocVolatile=*/false,
150                            IsInitializer);
151
152    if (ShouldDestroyTemporaries) {
153      // Pop temporaries.
154      while (LiveTemporaries.size() > OldNumLiveTemporaries)
155        PopCXXTemporary();
156    }
157
158    if (IsInitializer) {
159      // We might have to destroy the temporary variable.
160      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
161        if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
162          if (!ClassDecl->hasTrivialDestructor()) {
163            const CXXDestructorDecl *Dtor =
164              ClassDecl->getDestructor(getContext());
165
166            {
167              DelayedCleanupBlock Scope(*this);
168              EmitCXXDestructorCall(Dtor, Dtor_Complete,
169                                    Val.getAggregateAddr());
170
171              // Make sure to jump to the exit block.
172              EmitBranch(Scope.getCleanupExitBlock());
173            }
174            if (Exceptions) {
175              EHCleanupBlock Cleanup(*this);
176              EmitCXXDestructorCall(Dtor, Dtor_Complete,
177                                    Val.getAggregateAddr());
178            }
179          }
180        }
181      }
182    }
183
184    // Check if need to perform the derived-to-base cast.
185    if (BaseClassDecl) {
186      llvm::Value *Derived = Val.getAggregateAddr();
187      llvm::Value *Base =
188        GetAddressOfBaseClass(Derived, DerivedClassDecl, BaseClassDecl,
189                              /*NullCheckValue=*/false);
190      return RValue::get(Base);
191    }
192  }
193
194  if (Val.isAggregate()) {
195    Val = RValue::get(Val.getAggregateAddr());
196  } else {
197    // Create a temporary variable that we can bind the reference to.
198    llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()),
199                                         "reftmp");
200    if (Val.isScalar())
201      EmitStoreOfScalar(Val.getScalarVal(), Temp, false, E->getType());
202    else
203      StoreComplexToAddr(Val.getComplexVal(), Temp, false);
204    Val = RValue::get(Temp);
205  }
206
207  return Val;
208}
209
210
211/// getAccessedFieldNo - Given an encoded value and a result number, return the
212/// input field number being accessed.
213unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
214                                             const llvm::Constant *Elts) {
215  if (isa<llvm::ConstantAggregateZero>(Elts))
216    return 0;
217
218  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
219}
220
221void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
222  if (!CatchUndefined)
223    return;
224
225  const llvm::IntegerType *Size_tTy
226    = llvm::IntegerType::get(VMContext, LLVMPointerWidth);
227  Address = Builder.CreateBitCast(Address, PtrToInt8Ty);
228
229  const llvm::Type *ResType[] = {
230    Size_tTy
231  };
232  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, ResType, 1);
233  const llvm::IntegerType *IntTy = cast<llvm::IntegerType>(
234    CGM.getTypes().ConvertType(CGM.getContext().IntTy));
235  // In time, people may want to control this and use a 1 here.
236  llvm::Value *Arg = llvm::ConstantInt::get(IntTy, 0);
237  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
238  llvm::BasicBlock *Cont = createBasicBlock();
239  llvm::BasicBlock *Check = createBasicBlock();
240  llvm::Value *NegativeOne = llvm::ConstantInt::get(Size_tTy, -1ULL);
241  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
242
243  EmitBlock(Check);
244  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
245                                        llvm::ConstantInt::get(Size_tTy, Size)),
246                       Cont, getTrapBB());
247  EmitBlock(Cont);
248}
249
250
251llvm::Value *CodeGenFunction::
252EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
253                        bool isInc, bool isPre) {
254  QualType ValTy = E->getSubExpr()->getType();
255  llvm::Value *InVal = EmitLoadOfLValue(LV, ValTy).getScalarVal();
256
257  int AmountVal = isInc ? 1 : -1;
258
259  if (ValTy->isPointerType() &&
260      ValTy->getAs<PointerType>()->isVariableArrayType()) {
261    // The amount of the addition/subtraction needs to account for the VLA size
262    ErrorUnsupported(E, "VLA pointer inc/dec");
263  }
264
265  llvm::Value *NextVal;
266  if (const llvm::PointerType *PT =
267      dyn_cast<llvm::PointerType>(InVal->getType())) {
268    llvm::Constant *Inc =
269    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), AmountVal);
270    if (!isa<llvm::FunctionType>(PT->getElementType())) {
271      QualType PTEE = ValTy->getPointeeType();
272      if (const ObjCInterfaceType *OIT =
273          dyn_cast<ObjCInterfaceType>(PTEE)) {
274        // Handle interface types, which are not represented with a concrete
275        // type.
276        int size = getContext().getTypeSize(OIT) / 8;
277        if (!isInc)
278          size = -size;
279        Inc = llvm::ConstantInt::get(Inc->getType(), size);
280        const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
281        InVal = Builder.CreateBitCast(InVal, i8Ty);
282        NextVal = Builder.CreateGEP(InVal, Inc, "add.ptr");
283        llvm::Value *lhs = LV.getAddress();
284        lhs = Builder.CreateBitCast(lhs, llvm::PointerType::getUnqual(i8Ty));
285        LV = LValue::MakeAddr(lhs, MakeQualifiers(ValTy));
286      } else
287        NextVal = Builder.CreateInBoundsGEP(InVal, Inc, "ptrincdec");
288    } else {
289      const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
290      NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp");
291      NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec");
292      NextVal = Builder.CreateBitCast(NextVal, InVal->getType());
293    }
294  } else if (InVal->getType() == llvm::Type::getInt1Ty(VMContext) && isInc) {
295    // Bool++ is an interesting case, due to promotion rules, we get:
296    // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 ->
297    // Bool = ((int)Bool+1) != 0
298    // An interesting aspect of this is that increment is always true.
299    // Decrement does not have this property.
300    NextVal = llvm::ConstantInt::getTrue(VMContext);
301  } else if (isa<llvm::IntegerType>(InVal->getType())) {
302    NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
303
304    // Signed integer overflow is undefined behavior.
305    if (ValTy->isSignedIntegerType())
306      NextVal = Builder.CreateNSWAdd(InVal, NextVal, isInc ? "inc" : "dec");
307    else
308      NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
309  } else {
310    // Add the inc/dec to the real part.
311    if (InVal->getType()->isFloatTy())
312      NextVal =
313      llvm::ConstantFP::get(VMContext,
314                            llvm::APFloat(static_cast<float>(AmountVal)));
315    else if (InVal->getType()->isDoubleTy())
316      NextVal =
317      llvm::ConstantFP::get(VMContext,
318                            llvm::APFloat(static_cast<double>(AmountVal)));
319    else {
320      llvm::APFloat F(static_cast<float>(AmountVal));
321      bool ignored;
322      F.convert(Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
323                &ignored);
324      NextVal = llvm::ConstantFP::get(VMContext, F);
325    }
326    NextVal = Builder.CreateFAdd(InVal, NextVal, isInc ? "inc" : "dec");
327  }
328
329  // Store the updated result through the lvalue.
330  if (LV.isBitfield())
331    EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy, &NextVal);
332  else
333    EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy);
334
335  // If this is a postinc, return the value read from memory, otherwise use the
336  // updated value.
337  return isPre ? NextVal : InVal;
338}
339
340
341CodeGenFunction::ComplexPairTy CodeGenFunction::
342EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
343                         bool isInc, bool isPre) {
344  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
345                                            LV.isVolatileQualified());
346
347  llvm::Value *NextVal;
348  if (isa<llvm::IntegerType>(InVal.first->getType())) {
349    uint64_t AmountVal = isInc ? 1 : -1;
350    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
351
352    // Add the inc/dec to the real part.
353    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
354  } else {
355    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
356    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
357    if (!isInc)
358      FVal.changeSign();
359    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
360
361    // Add the inc/dec to the real part.
362    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
363  }
364
365  ComplexPairTy IncVal(NextVal, InVal.second);
366
367  // Store the updated result through the lvalue.
368  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
369
370  // If this is a postinc, return the value read from memory, otherwise use the
371  // updated value.
372  return isPre ? IncVal : InVal;
373}
374
375
376//===----------------------------------------------------------------------===//
377//                         LValue Expression Emission
378//===----------------------------------------------------------------------===//
379
380RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
381  if (Ty->isVoidType())
382    return RValue::get(0);
383
384  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
385    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
386    llvm::Value *U = llvm::UndefValue::get(EltTy);
387    return RValue::getComplex(std::make_pair(U, U));
388  }
389
390  if (hasAggregateLLVMType(Ty)) {
391    const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
392    return RValue::getAggregate(llvm::UndefValue::get(LTy));
393  }
394
395  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
396}
397
398RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
399                                              const char *Name) {
400  ErrorUnsupported(E, Name);
401  return GetUndefRValue(E->getType());
402}
403
404LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
405                                              const char *Name) {
406  ErrorUnsupported(E, Name);
407  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
408  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
409                          MakeQualifiers(E->getType()));
410}
411
412LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
413  LValue LV = EmitLValue(E);
414  if (!isa<DeclRefExpr>(E) && !LV.isBitfield() && LV.isSimple())
415    EmitCheck(LV.getAddress(), getContext().getTypeSize(E->getType()) / 8);
416  return LV;
417}
418
419/// EmitLValue - Emit code to compute a designator that specifies the location
420/// of the expression.
421///
422/// This can return one of two things: a simple address or a bitfield reference.
423/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
424/// an LLVM pointer type.
425///
426/// If this returns a bitfield reference, nothing about the pointee type of the
427/// LLVM value is known: For example, it may not be a pointer to an integer.
428///
429/// If this returns a normal address, and if the lvalue's C type is fixed size,
430/// this method guarantees that the returned pointer type will point to an LLVM
431/// type of the same size of the lvalue's type.  If the lvalue has a variable
432/// length type, this is not possible.
433///
434LValue CodeGenFunction::EmitLValue(const Expr *E) {
435  switch (E->getStmtClass()) {
436  default: return EmitUnsupportedLValue(E, "l-value expression");
437
438  case Expr::ObjCIsaExprClass:
439    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
440  case Expr::BinaryOperatorClass:
441    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
442  case Expr::CallExprClass:
443  case Expr::CXXMemberCallExprClass:
444  case Expr::CXXOperatorCallExprClass:
445    return EmitCallExprLValue(cast<CallExpr>(E));
446  case Expr::VAArgExprClass:
447    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
448  case Expr::DeclRefExprClass:
449    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
450  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
451  case Expr::PredefinedExprClass:
452    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
453  case Expr::StringLiteralClass:
454    return EmitStringLiteralLValue(cast<StringLiteral>(E));
455  case Expr::ObjCEncodeExprClass:
456    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
457
458  case Expr::BlockDeclRefExprClass:
459    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
460
461  case Expr::CXXTemporaryObjectExprClass:
462  case Expr::CXXConstructExprClass:
463    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
464  case Expr::CXXBindTemporaryExprClass:
465    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
466  case Expr::CXXExprWithTemporariesClass:
467    return EmitCXXExprWithTemporariesLValue(cast<CXXExprWithTemporaries>(E));
468  case Expr::CXXZeroInitValueExprClass:
469    return EmitNullInitializationLValue(cast<CXXZeroInitValueExpr>(E));
470  case Expr::CXXDefaultArgExprClass:
471    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
472  case Expr::CXXTypeidExprClass:
473    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
474
475  case Expr::ObjCMessageExprClass:
476    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
477  case Expr::ObjCIvarRefExprClass:
478    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
479  case Expr::ObjCPropertyRefExprClass:
480    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
481  case Expr::ObjCImplicitSetterGetterRefExprClass:
482    return EmitObjCKVCRefLValue(cast<ObjCImplicitSetterGetterRefExpr>(E));
483  case Expr::ObjCSuperExprClass:
484    return EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
485
486  case Expr::StmtExprClass:
487    return EmitStmtExprLValue(cast<StmtExpr>(E));
488  case Expr::UnaryOperatorClass:
489    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
490  case Expr::ArraySubscriptExprClass:
491    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
492  case Expr::ExtVectorElementExprClass:
493    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
494  case Expr::MemberExprClass:
495    return EmitMemberExpr(cast<MemberExpr>(E));
496  case Expr::CompoundLiteralExprClass:
497    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
498  case Expr::ConditionalOperatorClass:
499    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
500  case Expr::ChooseExprClass:
501    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
502  case Expr::ImplicitCastExprClass:
503  case Expr::CStyleCastExprClass:
504  case Expr::CXXFunctionalCastExprClass:
505  case Expr::CXXStaticCastExprClass:
506  case Expr::CXXDynamicCastExprClass:
507  case Expr::CXXReinterpretCastExprClass:
508  case Expr::CXXConstCastExprClass:
509    return EmitCastLValue(cast<CastExpr>(E));
510  }
511}
512
513llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
514                                               QualType Ty) {
515  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
516  if (Volatile)
517    Load->setVolatile(true);
518
519  // Bool can have different representation in memory than in registers.
520  llvm::Value *V = Load;
521  if (Ty->isBooleanType())
522    if (V->getType() != llvm::Type::getInt1Ty(VMContext))
523      V = Builder.CreateTrunc(V, llvm::Type::getInt1Ty(VMContext), "tobool");
524
525  return V;
526}
527
528void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
529                                        bool Volatile, QualType Ty) {
530
531  if (Ty->isBooleanType()) {
532    // Bool can have different representation in memory than in registers.
533    const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
534    Value = Builder.CreateIntCast(Value, DstPtr->getElementType(), false);
535  }
536  Builder.CreateStore(Value, Addr, Volatile);
537}
538
539/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
540/// method emits the address of the lvalue, then loads the result as an rvalue,
541/// returning the rvalue.
542RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
543  if (LV.isObjCWeak()) {
544    // load of a __weak object.
545    llvm::Value *AddrWeakObj = LV.getAddress();
546    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
547                                                             AddrWeakObj));
548  }
549
550  if (LV.isSimple()) {
551    llvm::Value *Ptr = LV.getAddress();
552    const llvm::Type *EltTy =
553      cast<llvm::PointerType>(Ptr->getType())->getElementType();
554
555    // Simple scalar l-value.
556    //
557    // FIXME: We shouldn't have to use isSingleValueType here.
558    if (EltTy->isSingleValueType())
559      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
560                                          ExprType));
561
562    assert(ExprType->isFunctionType() && "Unknown scalar value");
563    return RValue::get(Ptr);
564  }
565
566  if (LV.isVectorElt()) {
567    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
568                                          LV.isVolatileQualified(), "tmp");
569    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
570                                                    "vecext"));
571  }
572
573  // If this is a reference to a subset of the elements of a vector, either
574  // shuffle the input or extract/insert them as appropriate.
575  if (LV.isExtVectorElt())
576    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
577
578  if (LV.isBitfield())
579    return EmitLoadOfBitfieldLValue(LV, ExprType);
580
581  if (LV.isPropertyRef())
582    return EmitLoadOfPropertyRefLValue(LV, ExprType);
583
584  assert(LV.isKVCRef() && "Unknown LValue type!");
585  return EmitLoadOfKVCRefLValue(LV, ExprType);
586}
587
588RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
589                                                 QualType ExprType) {
590  unsigned StartBit = LV.getBitfieldStartBit();
591  unsigned BitfieldSize = LV.getBitfieldSize();
592  llvm::Value *Ptr = LV.getBitfieldAddr();
593
594  const llvm::Type *EltTy =
595    cast<llvm::PointerType>(Ptr->getType())->getElementType();
596  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
597
598  // In some cases the bitfield may straddle two memory locations.  Currently we
599  // load the entire bitfield, then do the magic to sign-extend it if
600  // necessary. This results in somewhat more code than necessary for the common
601  // case (one load), since two shifts accomplish both the masking and sign
602  // extension.
603  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
604  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
605
606  // Shift to proper location.
607  if (StartBit)
608    Val = Builder.CreateLShr(Val, StartBit, "bf.lo");
609
610  // Mask off unused bits.
611  llvm::Constant *LowMask = llvm::ConstantInt::get(VMContext,
612                                llvm::APInt::getLowBitsSet(EltTySize, LowBits));
613  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
614
615  // Fetch the high bits if necessary.
616  if (LowBits < BitfieldSize) {
617    unsigned HighBits = BitfieldSize - LowBits;
618    llvm::Value *HighPtr = Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
619                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
620    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
621                                              LV.isVolatileQualified(),
622                                              "tmp");
623
624    // Mask off unused bits.
625    llvm::Constant *HighMask = llvm::ConstantInt::get(VMContext,
626                               llvm::APInt::getLowBitsSet(EltTySize, HighBits));
627    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
628
629    // Shift to proper location and or in to bitfield value.
630    HighVal = Builder.CreateShl(HighVal, LowBits);
631    Val = Builder.CreateOr(Val, HighVal, "bf.val");
632  }
633
634  // Sign extend if necessary.
635  if (LV.isBitfieldSigned()) {
636    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
637                                                    EltTySize - BitfieldSize);
638    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
639                             ExtraBits, "bf.val.sext");
640  }
641
642  // The bitfield type and the normal type differ when the storage sizes differ
643  // (currently just _Bool).
644  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
645
646  return RValue::get(Val);
647}
648
649RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
650                                                    QualType ExprType) {
651  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
652}
653
654RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
655                                               QualType ExprType) {
656  return EmitObjCPropertyGet(LV.getKVCRefExpr());
657}
658
659// If this is a reference to a subset of the elements of a vector, create an
660// appropriate shufflevector.
661RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
662                                                         QualType ExprType) {
663  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
664                                        LV.isVolatileQualified(), "tmp");
665
666  const llvm::Constant *Elts = LV.getExtVectorElts();
667
668  // If the result of the expression is a non-vector type, we must be extracting
669  // a single element.  Just codegen as an extractelement.
670  const VectorType *ExprVT = ExprType->getAs<VectorType>();
671  if (!ExprVT) {
672    unsigned InIdx = getAccessedFieldNo(0, Elts);
673    llvm::Value *Elt = llvm::ConstantInt::get(
674                                      llvm::Type::getInt32Ty(VMContext), InIdx);
675    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
676  }
677
678  // Always use shuffle vector to try to retain the original program structure
679  unsigned NumResultElts = ExprVT->getNumElements();
680
681  llvm::SmallVector<llvm::Constant*, 4> Mask;
682  for (unsigned i = 0; i != NumResultElts; ++i) {
683    unsigned InIdx = getAccessedFieldNo(i, Elts);
684    Mask.push_back(llvm::ConstantInt::get(
685                                     llvm::Type::getInt32Ty(VMContext), InIdx));
686  }
687
688  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
689  Vec = Builder.CreateShuffleVector(Vec,
690                                    llvm::UndefValue::get(Vec->getType()),
691                                    MaskV, "tmp");
692  return RValue::get(Vec);
693}
694
695
696
697/// EmitStoreThroughLValue - Store the specified rvalue into the specified
698/// lvalue, where both are guaranteed to the have the same type, and that type
699/// is 'Ty'.
700void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
701                                             QualType Ty) {
702  if (!Dst.isSimple()) {
703    if (Dst.isVectorElt()) {
704      // Read/modify/write the vector, inserting the new element.
705      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
706                                            Dst.isVolatileQualified(), "tmp");
707      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
708                                        Dst.getVectorIdx(), "vecins");
709      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
710      return;
711    }
712
713    // If this is an update of extended vector elements, insert them as
714    // appropriate.
715    if (Dst.isExtVectorElt())
716      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
717
718    if (Dst.isBitfield())
719      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
720
721    if (Dst.isPropertyRef())
722      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
723
724    assert(Dst.isKVCRef() && "Unknown LValue type");
725    return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
726  }
727
728  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
729    // load of a __weak object.
730    llvm::Value *LvalueDst = Dst.getAddress();
731    llvm::Value *src = Src.getScalarVal();
732     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
733    return;
734  }
735
736  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
737    // load of a __strong object.
738    llvm::Value *LvalueDst = Dst.getAddress();
739    llvm::Value *src = Src.getScalarVal();
740    if (Dst.isObjCIvar()) {
741      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
742      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
743      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
744      llvm::Value *dst = RHS;
745      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
746      llvm::Value *LHS =
747        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
748      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
749      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
750                                              BytesBetween);
751    } else if (Dst.isGlobalObjCRef())
752      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
753    else
754      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
755    return;
756  }
757
758  assert(Src.isScalar() && "Can't emit an agg store with this method");
759  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
760                    Dst.isVolatileQualified(), Ty);
761}
762
763void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
764                                                     QualType Ty,
765                                                     llvm::Value **Result) {
766  unsigned StartBit = Dst.getBitfieldStartBit();
767  unsigned BitfieldSize = Dst.getBitfieldSize();
768  llvm::Value *Ptr = Dst.getBitfieldAddr();
769
770  const llvm::Type *EltTy =
771    cast<llvm::PointerType>(Ptr->getType())->getElementType();
772  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
773
774  // Get the new value, cast to the appropriate type and masked to exactly the
775  // size of the bit-field.
776  llvm::Value *SrcVal = Src.getScalarVal();
777  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
778  llvm::Constant *Mask = llvm::ConstantInt::get(VMContext,
779                           llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
780  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
781
782  // Return the new value of the bit-field, if requested.
783  if (Result) {
784    // Cast back to the proper type for result.
785    const llvm::Type *SrcTy = SrcVal->getType();
786    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
787                                                  "bf.reload.val");
788
789    // Sign extend if necessary.
790    if (Dst.isBitfieldSigned()) {
791      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
792      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
793                                                      SrcTySize - BitfieldSize);
794      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
795                                    ExtraBits, "bf.reload.sext");
796    }
797
798    *Result = SrcTrunc;
799  }
800
801  // In some cases the bitfield may straddle two memory locations.  Emit the low
802  // part first and check to see if the high needs to be done.
803  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
804  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
805                                           "bf.prev.low");
806
807  // Compute the mask for zero-ing the low part of this bitfield.
808  llvm::Constant *InvMask =
809    llvm::ConstantInt::get(VMContext,
810             ~llvm::APInt::getBitsSet(EltTySize, StartBit, StartBit + LowBits));
811
812  // Compute the new low part as
813  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
814  // with the shift of NewVal implicitly stripping the high bits.
815  llvm::Value *NewLowVal =
816    Builder.CreateShl(NewVal, StartBit, "bf.value.lo");
817  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
818  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
819
820  // Write back.
821  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
822
823  // If the low part doesn't cover the bitfield emit a high part.
824  if (LowBits < BitfieldSize) {
825    unsigned HighBits = BitfieldSize - LowBits;
826    llvm::Value *HighPtr =  Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
827                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
828    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
829                                              Dst.isVolatileQualified(),
830                                              "bf.prev.hi");
831
832    // Compute the mask for zero-ing the high part of this bitfield.
833    llvm::Constant *InvMask =
834      llvm::ConstantInt::get(VMContext, ~llvm::APInt::getLowBitsSet(EltTySize,
835                               HighBits));
836
837    // Compute the new high part as
838    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
839    // where the high bits of NewVal have already been cleared and the
840    // shift stripping the low bits.
841    llvm::Value *NewHighVal =
842      Builder.CreateLShr(NewVal, LowBits, "bf.value.high");
843    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
844    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
845
846    // Write back.
847    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
848  }
849}
850
851void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
852                                                        LValue Dst,
853                                                        QualType Ty) {
854  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
855}
856
857void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
858                                                   LValue Dst,
859                                                   QualType Ty) {
860  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
861}
862
863void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
864                                                               LValue Dst,
865                                                               QualType Ty) {
866  // This access turns into a read/modify/write of the vector.  Load the input
867  // value now.
868  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
869                                        Dst.isVolatileQualified(), "tmp");
870  const llvm::Constant *Elts = Dst.getExtVectorElts();
871
872  llvm::Value *SrcVal = Src.getScalarVal();
873
874  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
875    unsigned NumSrcElts = VTy->getNumElements();
876    unsigned NumDstElts =
877       cast<llvm::VectorType>(Vec->getType())->getNumElements();
878    if (NumDstElts == NumSrcElts) {
879      // Use shuffle vector is the src and destination are the same number of
880      // elements and restore the vector mask since it is on the side it will be
881      // stored.
882      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
883      for (unsigned i = 0; i != NumSrcElts; ++i) {
884        unsigned InIdx = getAccessedFieldNo(i, Elts);
885        Mask[InIdx] = llvm::ConstantInt::get(
886                                          llvm::Type::getInt32Ty(VMContext), i);
887      }
888
889      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
890      Vec = Builder.CreateShuffleVector(SrcVal,
891                                        llvm::UndefValue::get(Vec->getType()),
892                                        MaskV, "tmp");
893    } else if (NumDstElts > NumSrcElts) {
894      // Extended the source vector to the same length and then shuffle it
895      // into the destination.
896      // FIXME: since we're shuffling with undef, can we just use the indices
897      //        into that?  This could be simpler.
898      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
899      const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
900      unsigned i;
901      for (i = 0; i != NumSrcElts; ++i)
902        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
903      for (; i != NumDstElts; ++i)
904        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
905      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
906                                                        ExtMask.size());
907      llvm::Value *ExtSrcVal =
908        Builder.CreateShuffleVector(SrcVal,
909                                    llvm::UndefValue::get(SrcVal->getType()),
910                                    ExtMaskV, "tmp");
911      // build identity
912      llvm::SmallVector<llvm::Constant*, 4> Mask;
913      for (unsigned i = 0; i != NumDstElts; ++i)
914        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
915
916      // modify when what gets shuffled in
917      for (unsigned i = 0; i != NumSrcElts; ++i) {
918        unsigned Idx = getAccessedFieldNo(i, Elts);
919        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
920      }
921      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
922      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
923    } else {
924      // We should never shorten the vector
925      assert(0 && "unexpected shorten vector length");
926    }
927  } else {
928    // If the Src is a scalar (not a vector) it must be updating one element.
929    unsigned InIdx = getAccessedFieldNo(0, Elts);
930    const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
931    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
932    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
933  }
934
935  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
936}
937
938// setObjCGCLValueClass - sets class of he lvalue for the purpose of
939// generating write-barries API. It is currently a global, ivar,
940// or neither.
941static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
942                                 LValue &LV) {
943  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
944    return;
945
946  if (isa<ObjCIvarRefExpr>(E)) {
947    LV.SetObjCIvar(LV, true);
948    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
949    LV.setBaseIvarExp(Exp->getBase());
950    LV.SetObjCArray(LV, E->getType()->isArrayType());
951    return;
952  }
953
954  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
955    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
956      if ((VD->isBlockVarDecl() && !VD->hasLocalStorage()) ||
957          VD->isFileVarDecl())
958        LV.SetGlobalObjCRef(LV, true);
959    }
960    LV.SetObjCArray(LV, E->getType()->isArrayType());
961    return;
962  }
963
964  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
965    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
966    return;
967  }
968
969  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
970    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
971    if (LV.isObjCIvar()) {
972      // If cast is to a structure pointer, follow gcc's behavior and make it
973      // a non-ivar write-barrier.
974      QualType ExpTy = E->getType();
975      if (ExpTy->isPointerType())
976        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
977      if (ExpTy->isRecordType())
978        LV.SetObjCIvar(LV, false);
979    }
980    return;
981  }
982  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
983    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
984    return;
985  }
986
987  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
988    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
989    return;
990  }
991
992  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
993    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
994    if (LV.isObjCIvar() && !LV.isObjCArray())
995      // Using array syntax to assigning to what an ivar points to is not
996      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
997      LV.SetObjCIvar(LV, false);
998    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
999      // Using array syntax to assigning to what global points to is not
1000      // same as assigning to the global itself. {id *G;} G[i] = 0;
1001      LV.SetGlobalObjCRef(LV, false);
1002    return;
1003  }
1004
1005  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1006    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1007    // We don't know if member is an 'ivar', but this flag is looked at
1008    // only in the context of LV.isObjCIvar().
1009    LV.SetObjCArray(LV, E->getType()->isArrayType());
1010    return;
1011  }
1012}
1013
1014static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1015                                      const Expr *E, const VarDecl *VD) {
1016  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1017         "Var decl must have external storage or be a file var decl!");
1018
1019  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1020  if (VD->getType()->isReferenceType())
1021    V = CGF.Builder.CreateLoad(V, "tmp");
1022  LValue LV = LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1023  setObjCGCLValueClass(CGF.getContext(), E, LV);
1024  return LV;
1025}
1026
1027static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1028                                      const Expr *E, const FunctionDecl *FD) {
1029  llvm::Value* V = CGF.CGM.GetAddrOfFunction(FD);
1030  if (!FD->hasPrototype()) {
1031    if (const FunctionProtoType *Proto =
1032            FD->getType()->getAs<FunctionProtoType>()) {
1033      // Ugly case: for a K&R-style definition, the type of the definition
1034      // isn't the same as the type of a use.  Correct for this with a
1035      // bitcast.
1036      QualType NoProtoType =
1037          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1038      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1039      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1040    }
1041  }
1042  return LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1043}
1044
1045LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1046  const NamedDecl *ND = E->getDecl();
1047
1048  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1049
1050    // Check if this is a global variable.
1051    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1052      return EmitGlobalVarDeclLValue(*this, E, VD);
1053
1054    bool NonGCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
1055
1056    llvm::Value *V = LocalDeclMap[VD];
1057    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1058
1059    Qualifiers Quals = MakeQualifiers(E->getType());
1060    // local variables do not get their gc attribute set.
1061    // local static?
1062    if (NonGCable) Quals.removeObjCGCAttr();
1063
1064    if (VD->hasAttr<BlocksAttr>()) {
1065      V = Builder.CreateStructGEP(V, 1, "forwarding");
1066      V = Builder.CreateLoad(V);
1067      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
1068                                  VD->getNameAsString());
1069    }
1070    if (VD->getType()->isReferenceType())
1071      V = Builder.CreateLoad(V, "tmp");
1072    LValue LV = LValue::MakeAddr(V, Quals);
1073    LValue::SetObjCNonGC(LV, NonGCable);
1074    setObjCGCLValueClass(getContext(), E, LV);
1075    return LV;
1076  }
1077
1078  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1079    return EmitFunctionDeclLValue(*this, E, FD);
1080
1081  // FIXME: the qualifier check does not seem sufficient here
1082  if (E->getQualifier()) {
1083    const FieldDecl *FD = cast<FieldDecl>(ND);
1084    llvm::Value *V = CGM.EmitPointerToDataMember(FD);
1085
1086    return LValue::MakeAddr(V, MakeQualifiers(FD->getType()));
1087  }
1088
1089  assert(false && "Unhandled DeclRefExpr");
1090
1091  // an invalid LValue, but the assert will
1092  // ensure that this point is never reached.
1093  return LValue();
1094}
1095
1096LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1097  return LValue::MakeAddr(GetAddrOfBlockDecl(E), MakeQualifiers(E->getType()));
1098}
1099
1100LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1101  // __extension__ doesn't affect lvalue-ness.
1102  if (E->getOpcode() == UnaryOperator::Extension)
1103    return EmitLValue(E->getSubExpr());
1104
1105  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1106  switch (E->getOpcode()) {
1107  default: assert(0 && "Unknown unary operator lvalue!");
1108  case UnaryOperator::Deref: {
1109    QualType T = E->getSubExpr()->getType()->getPointeeType();
1110    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1111
1112    Qualifiers Quals = MakeQualifiers(T);
1113    Quals.setAddressSpace(ExprTy.getAddressSpace());
1114
1115    LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()), Quals);
1116    // We should not generate __weak write barrier on indirect reference
1117    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1118    // But, we continue to generate __strong write barrier on indirect write
1119    // into a pointer to object.
1120    if (getContext().getLangOptions().ObjC1 &&
1121        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1122        LV.isObjCWeak())
1123      LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1124    return LV;
1125  }
1126  case UnaryOperator::Real:
1127  case UnaryOperator::Imag: {
1128    LValue LV = EmitLValue(E->getSubExpr());
1129    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
1130    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
1131                                                    Idx, "idx"),
1132                            MakeQualifiers(ExprTy));
1133  }
1134  case UnaryOperator::PreInc:
1135  case UnaryOperator::PreDec: {
1136    LValue LV = EmitLValue(E->getSubExpr());
1137    bool isInc = E->getOpcode() == UnaryOperator::PreInc;
1138
1139    if (E->getType()->isAnyComplexType())
1140      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1141    else
1142      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1143    return LV;
1144  }
1145  }
1146}
1147
1148LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1149  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E),
1150                          Qualifiers());
1151}
1152
1153LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1154  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1155                          Qualifiers());
1156}
1157
1158
1159LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
1160  std::string GlobalVarName;
1161
1162  switch (Type) {
1163  default: assert(0 && "Invalid type");
1164  case PredefinedExpr::Func:
1165    GlobalVarName = "__func__.";
1166    break;
1167  case PredefinedExpr::Function:
1168    GlobalVarName = "__FUNCTION__.";
1169    break;
1170  case PredefinedExpr::PrettyFunction:
1171    GlobalVarName = "__PRETTY_FUNCTION__.";
1172    break;
1173  }
1174
1175  llvm::StringRef FnName = CurFn->getName();
1176  if (FnName.startswith("\01"))
1177    FnName = FnName.substr(1);
1178  GlobalVarName += FnName;
1179
1180  std::string FunctionName =
1181    PredefinedExpr::ComputeName(getContext(), (PredefinedExpr::IdentType)Type,
1182                                CurCodeDecl);
1183
1184  llvm::Constant *C =
1185    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1186  return LValue::MakeAddr(C, Qualifiers());
1187}
1188
1189LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1190  switch (E->getIdentType()) {
1191  default:
1192    return EmitUnsupportedLValue(E, "predefined expression");
1193  case PredefinedExpr::Func:
1194  case PredefinedExpr::Function:
1195  case PredefinedExpr::PrettyFunction:
1196    return EmitPredefinedFunctionName(E->getIdentType());
1197  }
1198}
1199
1200llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1201  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1202
1203  // If we are not optimzing, don't collapse all calls to trap in the function
1204  // to the same call, that way, in the debugger they can see which operation
1205  // did in fact fail.  If we are optimizing, we collpase all call to trap down
1206  // to just one per function to save on codesize.
1207  if (GCO.OptimizationLevel
1208      && TrapBB)
1209    return TrapBB;
1210
1211  llvm::BasicBlock *Cont = 0;
1212  if (HaveInsertPoint()) {
1213    Cont = createBasicBlock("cont");
1214    EmitBranch(Cont);
1215  }
1216  TrapBB = createBasicBlock("trap");
1217  EmitBlock(TrapBB);
1218
1219  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1220  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1221  TrapCall->setDoesNotReturn();
1222  TrapCall->setDoesNotThrow();
1223  Builder.CreateUnreachable();
1224
1225  if (Cont)
1226    EmitBlock(Cont);
1227  return TrapBB;
1228}
1229
1230LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1231  // The index must always be an integer, which is not an aggregate.  Emit it.
1232  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1233  QualType IdxTy  = E->getIdx()->getType();
1234  bool IdxSigned = IdxTy->isSignedIntegerType();
1235
1236  // If the base is a vector type, then we are forming a vector element lvalue
1237  // with this subscript.
1238  if (E->getBase()->getType()->isVectorType()) {
1239    // Emit the vector as an lvalue to get its address.
1240    LValue LHS = EmitLValue(E->getBase());
1241    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1242    Idx = Builder.CreateIntCast(Idx,
1243                          llvm::Type::getInt32Ty(VMContext), IdxSigned, "vidx");
1244    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1245                                 E->getBase()->getType().getCVRQualifiers());
1246  }
1247
1248  // The base must be a pointer, which is not an aggregate.  Emit it.
1249  llvm::Value *Base = EmitScalarExpr(E->getBase());
1250
1251  // Extend or truncate the index type to 32 or 64-bits.
1252  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1253  if (IdxBitwidth != LLVMPointerWidth)
1254    Idx = Builder.CreateIntCast(Idx,
1255                            llvm::IntegerType::get(VMContext, LLVMPointerWidth),
1256                                IdxSigned, "idxprom");
1257
1258  // FIXME: As llvm implements the object size checking, this can come out.
1259  if (CatchUndefined) {
1260    if (const ImplicitCastExpr *ICE=dyn_cast<ImplicitCastExpr>(E->getBase())) {
1261      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1262        if (ICE->getCastKind() == CastExpr::CK_ArrayToPointerDecay) {
1263          if (const ConstantArrayType *CAT
1264              = getContext().getAsConstantArrayType(DRE->getType())) {
1265            llvm::APInt Size = CAT->getSize();
1266            llvm::BasicBlock *Cont = createBasicBlock("cont");
1267            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1268                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1269                                 Cont, getTrapBB());
1270            EmitBlock(Cont);
1271          }
1272        }
1273      }
1274    }
1275  }
1276
1277  // We know that the pointer points to a type of the correct size, unless the
1278  // size is a VLA or Objective-C interface.
1279  llvm::Value *Address = 0;
1280  if (const VariableArrayType *VAT =
1281        getContext().getAsVariableArrayType(E->getType())) {
1282    llvm::Value *VLASize = GetVLASize(VAT);
1283
1284    Idx = Builder.CreateMul(Idx, VLASize);
1285
1286    QualType BaseType = getContext().getBaseElementType(VAT);
1287
1288    CharUnits BaseTypeSize = getContext().getTypeSizeInChars(BaseType);
1289    Idx = Builder.CreateUDiv(Idx,
1290                             llvm::ConstantInt::get(Idx->getType(),
1291                                 BaseTypeSize.getQuantity()));
1292    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1293  } else if (const ObjCInterfaceType *OIT =
1294             dyn_cast<ObjCInterfaceType>(E->getType())) {
1295    llvm::Value *InterfaceSize =
1296      llvm::ConstantInt::get(Idx->getType(),
1297          getContext().getTypeSizeInChars(OIT).getQuantity());
1298
1299    Idx = Builder.CreateMul(Idx, InterfaceSize);
1300
1301    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1302    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1303                                Idx, "arrayidx");
1304    Address = Builder.CreateBitCast(Address, Base->getType());
1305  } else {
1306    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1307  }
1308
1309  QualType T = E->getBase()->getType()->getPointeeType();
1310  assert(!T.isNull() &&
1311         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1312
1313  Qualifiers Quals = MakeQualifiers(T);
1314  Quals.setAddressSpace(E->getBase()->getType().getAddressSpace());
1315
1316  LValue LV = LValue::MakeAddr(Address, Quals);
1317  if (getContext().getLangOptions().ObjC1 &&
1318      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1319    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1320    setObjCGCLValueClass(getContext(), E, LV);
1321  }
1322  return LV;
1323}
1324
1325static
1326llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1327                                       llvm::SmallVector<unsigned, 4> &Elts) {
1328  llvm::SmallVector<llvm::Constant*, 4> CElts;
1329
1330  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1331    CElts.push_back(llvm::ConstantInt::get(
1332                                   llvm::Type::getInt32Ty(VMContext), Elts[i]));
1333
1334  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1335}
1336
1337LValue CodeGenFunction::
1338EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1339  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1340
1341  // Emit the base vector as an l-value.
1342  LValue Base;
1343
1344  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1345  if (E->isArrow()) {
1346    // If it is a pointer to a vector, emit the address and form an lvalue with
1347    // it.
1348    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1349    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1350    Qualifiers Quals = MakeQualifiers(PT->getPointeeType());
1351    Quals.removeObjCGCAttr();
1352    Base = LValue::MakeAddr(Ptr, Quals);
1353  } else if (E->getBase()->isLvalue(getContext()) == Expr::LV_Valid) {
1354    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1355    // emit the base as an lvalue.
1356    assert(E->getBase()->getType()->isVectorType());
1357    Base = EmitLValue(E->getBase());
1358  } else {
1359    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1360    assert(E->getBase()->getType()->getAs<VectorType>() &&
1361           "Result must be a vector");
1362    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1363
1364    // Store the vector to memory (because LValue wants an address).
1365    llvm::Value *VecMem = CreateTempAlloca(ConvertTypeForMem(
1366                                             E->getBase()->getType()));
1367    Builder.CreateStore(Vec, VecMem);
1368    Base = LValue::MakeAddr(VecMem, Qualifiers());
1369  }
1370
1371  // Encode the element access list into a vector of unsigned indices.
1372  llvm::SmallVector<unsigned, 4> Indices;
1373  E->getEncodedElementAccess(Indices);
1374
1375  if (Base.isSimple()) {
1376    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1377    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1378                                    Base.getVRQualifiers());
1379  }
1380  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1381
1382  llvm::Constant *BaseElts = Base.getExtVectorElts();
1383  llvm::SmallVector<llvm::Constant *, 4> CElts;
1384
1385  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1386    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1387      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1388    else
1389      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1390  }
1391  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1392  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1393                                  Base.getVRQualifiers());
1394}
1395
1396LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1397  bool isNonGC = false;
1398  Expr *BaseExpr = E->getBase();
1399  llvm::Value *BaseValue = NULL;
1400  Qualifiers BaseQuals;
1401
1402  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1403  if (E->isArrow()) {
1404    BaseValue = EmitScalarExpr(BaseExpr);
1405    const PointerType *PTy =
1406      BaseExpr->getType()->getAs<PointerType>();
1407    BaseQuals = PTy->getPointeeType().getQualifiers();
1408  } else if (isa<ObjCPropertyRefExpr>(BaseExpr->IgnoreParens()) ||
1409             isa<ObjCImplicitSetterGetterRefExpr>(
1410               BaseExpr->IgnoreParens())) {
1411    RValue RV = EmitObjCPropertyGet(BaseExpr);
1412    BaseValue = RV.getAggregateAddr();
1413    BaseQuals = BaseExpr->getType().getQualifiers();
1414  } else {
1415    LValue BaseLV = EmitLValue(BaseExpr);
1416    if (BaseLV.isNonGC())
1417      isNonGC = true;
1418    // FIXME: this isn't right for bitfields.
1419    BaseValue = BaseLV.getAddress();
1420    QualType BaseTy = BaseExpr->getType();
1421    BaseQuals = BaseTy.getQualifiers();
1422  }
1423
1424  NamedDecl *ND = E->getMemberDecl();
1425  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1426    LValue LV = EmitLValueForField(BaseValue, Field,
1427                                   BaseQuals.getCVRQualifiers());
1428    LValue::SetObjCNonGC(LV, isNonGC);
1429    setObjCGCLValueClass(getContext(), E, LV);
1430    return LV;
1431  }
1432
1433  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1434    return EmitGlobalVarDeclLValue(*this, E, VD);
1435
1436  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1437    return EmitFunctionDeclLValue(*this, E, FD);
1438
1439  assert(false && "Unhandled member declaration!");
1440  return LValue();
1441}
1442
1443LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
1444                                              const FieldDecl* Field,
1445                                              unsigned CVRQualifiers) {
1446  CodeGenTypes::BitFieldInfo Info = CGM.getTypes().getBitFieldInfo(Field);
1447
1448  // FIXME: CodeGenTypes should expose a method to get the appropriate type for
1449  // FieldTy (the appropriate type is ABI-dependent).
1450  const llvm::Type *FieldTy =
1451    CGM.getTypes().ConvertTypeForMem(Field->getType());
1452  const llvm::PointerType *BaseTy =
1453  cast<llvm::PointerType>(BaseValue->getType());
1454  unsigned AS = BaseTy->getAddressSpace();
1455  BaseValue = Builder.CreateBitCast(BaseValue,
1456                                    llvm::PointerType::get(FieldTy, AS),
1457                                    "tmp");
1458
1459  llvm::Value *Idx =
1460    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), Info.FieldNo);
1461  llvm::Value *V = Builder.CreateGEP(BaseValue, Idx, "tmp");
1462
1463  return LValue::MakeBitfield(V, Info.Start, Info.Size,
1464                              Field->getType()->isSignedIntegerType(),
1465                            Field->getType().getCVRQualifiers()|CVRQualifiers);
1466}
1467
1468LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
1469                                           const FieldDecl* Field,
1470                                           unsigned CVRQualifiers) {
1471  if (Field->isBitField())
1472    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1473
1474  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
1475  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1476
1477  // Match union field type.
1478  if (Field->getParent()->isUnion()) {
1479    const llvm::Type *FieldTy =
1480      CGM.getTypes().ConvertTypeForMem(Field->getType());
1481    const llvm::PointerType * BaseTy =
1482      cast<llvm::PointerType>(BaseValue->getType());
1483    unsigned AS = BaseTy->getAddressSpace();
1484    V = Builder.CreateBitCast(V,
1485                              llvm::PointerType::get(FieldTy, AS),
1486                              "tmp");
1487  }
1488  if (Field->getType()->isReferenceType())
1489    V = Builder.CreateLoad(V, "tmp");
1490
1491  Qualifiers Quals = MakeQualifiers(Field->getType());
1492  Quals.addCVRQualifiers(CVRQualifiers);
1493  // __weak attribute on a field is ignored.
1494  if (Quals.getObjCGCAttr() == Qualifiers::Weak)
1495    Quals.removeObjCGCAttr();
1496
1497  return LValue::MakeAddr(V, Quals);
1498}
1499
1500LValue
1501CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value* BaseValue,
1502                                                  const FieldDecl* Field,
1503                                                  unsigned CVRQualifiers) {
1504  QualType FieldType = Field->getType();
1505
1506  if (!FieldType->isReferenceType())
1507    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1508
1509  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
1510  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1511
1512  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1513
1514  return LValue::MakeAddr(V, MakeQualifiers(FieldType));
1515}
1516
1517LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1518  llvm::Value *DeclPtr = CreateTempAlloca(ConvertTypeForMem(E->getType()),
1519                                          ".compoundliteral");
1520
1521  const Expr* InitExpr = E->getInitializer();
1522  LValue Result = LValue::MakeAddr(DeclPtr, MakeQualifiers(E->getType()));
1523
1524  if (E->getType()->isComplexType())
1525    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1526  else if (hasAggregateLLVMType(E->getType()))
1527    EmitAnyExpr(InitExpr, DeclPtr, false);
1528  else
1529    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1530
1531  return Result;
1532}
1533
1534LValue
1535CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator* E) {
1536  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
1537    if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1538      Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1539      if (Live)
1540        return EmitLValue(Live);
1541    }
1542
1543    if (!E->getLHS())
1544      return EmitUnsupportedLValue(E, "conditional operator with missing LHS");
1545
1546    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1547    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1548    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1549
1550    EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1551
1552    // Any temporaries created here are conditional.
1553    BeginConditionalBranch();
1554    EmitBlock(LHSBlock);
1555    LValue LHS = EmitLValue(E->getLHS());
1556    EndConditionalBranch();
1557
1558    if (!LHS.isSimple())
1559      return EmitUnsupportedLValue(E, "conditional operator");
1560
1561    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1562    Builder.CreateStore(LHS.getAddress(), Temp);
1563    EmitBranch(ContBlock);
1564
1565    // Any temporaries created here are conditional.
1566    BeginConditionalBranch();
1567    EmitBlock(RHSBlock);
1568    LValue RHS = EmitLValue(E->getRHS());
1569    EndConditionalBranch();
1570    if (!RHS.isSimple())
1571      return EmitUnsupportedLValue(E, "conditional operator");
1572
1573    Builder.CreateStore(RHS.getAddress(), Temp);
1574    EmitBranch(ContBlock);
1575
1576    EmitBlock(ContBlock);
1577
1578    Temp = Builder.CreateLoad(Temp, "lv");
1579    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1580  }
1581
1582  // ?: here should be an aggregate.
1583  assert((hasAggregateLLVMType(E->getType()) &&
1584          !E->getType()->isAnyComplexType()) &&
1585         "Unexpected conditional operator!");
1586
1587  return EmitAggExprToLValue(E);
1588}
1589
1590/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1591/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1592/// otherwise if a cast is needed by the code generator in an lvalue context,
1593/// then it must mean that we need the address of an aggregate in order to
1594/// access one of its fields.  This can happen for all the reasons that casts
1595/// are permitted with aggregate result, including noop aggregate casts, and
1596/// cast from scalar to union.
1597LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1598  switch (E->getCastKind()) {
1599  default:
1600    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1601
1602  case CastExpr::CK_Dynamic: {
1603    LValue LV = EmitLValue(E->getSubExpr());
1604    llvm::Value *V = LV.getAddress();
1605    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1606    return LValue::MakeAddr(EmitDynamicCast(V, DCE),
1607                            MakeQualifiers(E->getType()));
1608  }
1609
1610  case CastExpr::CK_NoOp:
1611  case CastExpr::CK_ConstructorConversion:
1612  case CastExpr::CK_UserDefinedConversion:
1613  case CastExpr::CK_AnyPointerToObjCPointerCast:
1614    return EmitLValue(E->getSubExpr());
1615
1616  case CastExpr::CK_DerivedToBase: {
1617    const RecordType *DerivedClassTy =
1618      E->getSubExpr()->getType()->getAs<RecordType>();
1619    CXXRecordDecl *DerivedClassDecl =
1620      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1621
1622    const RecordType *BaseClassTy = E->getType()->getAs<RecordType>();
1623    CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseClassTy->getDecl());
1624
1625    LValue LV = EmitLValue(E->getSubExpr());
1626
1627    // Perform the derived-to-base conversion
1628    llvm::Value *Base =
1629      GetAddressOfBaseClass(LV.getAddress(), DerivedClassDecl,
1630                            BaseClassDecl, /*NullCheckValue=*/false);
1631
1632    return LValue::MakeAddr(Base, MakeQualifiers(E->getType()));
1633  }
1634  case CastExpr::CK_ToUnion:
1635    return EmitAggExprToLValue(E);
1636  case CastExpr::CK_BaseToDerived: {
1637    const RecordType *BaseClassTy =
1638      E->getSubExpr()->getType()->getAs<RecordType>();
1639    CXXRecordDecl *BaseClassDecl =
1640      cast<CXXRecordDecl>(BaseClassTy->getDecl());
1641
1642    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1643    CXXRecordDecl *DerivedClassDecl =
1644      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1645
1646    LValue LV = EmitLValue(E->getSubExpr());
1647
1648    // Perform the base-to-derived conversion
1649    llvm::Value *Derived =
1650      GetAddressOfDerivedClass(LV.getAddress(), BaseClassDecl,
1651                               DerivedClassDecl, /*NullCheckValue=*/false);
1652
1653    return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
1654  }
1655  case CastExpr::CK_BitCast: {
1656    // This must be a reinterpret_cast (or c-style equivalent).
1657    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1658
1659    LValue LV = EmitLValue(E->getSubExpr());
1660    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1661                                           ConvertType(CE->getTypeAsWritten()));
1662    return LValue::MakeAddr(V, MakeQualifiers(E->getType()));
1663  }
1664  }
1665}
1666
1667LValue CodeGenFunction::EmitNullInitializationLValue(
1668                                              const CXXZeroInitValueExpr *E) {
1669  QualType Ty = E->getType();
1670  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty));
1671  CharUnits Align = getContext().getTypeAlignInChars(Ty);
1672  Alloc->setAlignment(Align.getQuantity());
1673  LValue lvalue = LValue::MakeAddr(Alloc, Qualifiers());
1674  EmitMemSetToZero(lvalue.getAddress(), Ty);
1675  return lvalue;
1676}
1677
1678//===--------------------------------------------------------------------===//
1679//                             Expression Emission
1680//===--------------------------------------------------------------------===//
1681
1682
1683RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1684                                     ReturnValueSlot ReturnValue) {
1685  // Builtins never have block type.
1686  if (E->getCallee()->getType()->isBlockPointerType())
1687    return EmitBlockCallExpr(E, ReturnValue);
1688
1689  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1690    return EmitCXXMemberCallExpr(CE, ReturnValue);
1691
1692  const Decl *TargetDecl = 0;
1693  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1694    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1695      TargetDecl = DRE->getDecl();
1696      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1697        if (unsigned builtinID = FD->getBuiltinID())
1698          return EmitBuiltinExpr(FD, builtinID, E);
1699    }
1700  }
1701
1702  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1703    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1704      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1705
1706  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1707    // C++ [expr.pseudo]p1:
1708    //   The result shall only be used as the operand for the function call
1709    //   operator (), and the result of such a call has type void. The only
1710    //   effect is the evaluation of the postfix-expression before the dot or
1711    //   arrow.
1712    EmitScalarExpr(E->getCallee());
1713    return RValue::get(0);
1714  }
1715
1716  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1717  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1718                  E->arg_begin(), E->arg_end(), TargetDecl);
1719}
1720
1721LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1722  // Comma expressions just emit their LHS then their RHS as an l-value.
1723  if (E->getOpcode() == BinaryOperator::Comma) {
1724    EmitAnyExpr(E->getLHS());
1725    EnsureInsertPoint();
1726    return EmitLValue(E->getRHS());
1727  }
1728
1729  if (E->getOpcode() == BinaryOperator::PtrMemD ||
1730      E->getOpcode() == BinaryOperator::PtrMemI)
1731    return EmitPointerToDataMemberBinaryExpr(E);
1732
1733  // Can only get l-value for binary operator expressions which are a
1734  // simple assignment of aggregate type.
1735  if (E->getOpcode() != BinaryOperator::Assign)
1736    return EmitUnsupportedLValue(E, "binary l-value expression");
1737
1738  if (!hasAggregateLLVMType(E->getType())) {
1739    // Emit the LHS as an l-value.
1740    LValue LV = EmitLValue(E->getLHS());
1741
1742    llvm::Value *RHS = EmitScalarExpr(E->getRHS());
1743    EmitStoreOfScalar(RHS, LV.getAddress(), LV.isVolatileQualified(),
1744                      E->getType());
1745    return LV;
1746  }
1747
1748  return EmitAggExprToLValue(E);
1749}
1750
1751LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1752  RValue RV = EmitCallExpr(E);
1753
1754  if (!RV.isScalar())
1755    return LValue::MakeAddr(RV.getAggregateAddr(),MakeQualifiers(E->getType()));
1756
1757  assert(E->getCallReturnType()->isReferenceType() &&
1758         "Can't have a scalar return unless the return type is a "
1759         "reference type!");
1760
1761  return LValue::MakeAddr(RV.getScalarVal(), MakeQualifiers(E->getType()));
1762}
1763
1764LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1765  // FIXME: This shouldn't require another copy.
1766  return EmitAggExprToLValue(E);
1767}
1768
1769LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1770  llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()), "tmp");
1771  EmitCXXConstructExpr(Temp, E);
1772  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1773}
1774
1775LValue
1776CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1777  llvm::Value *Temp = EmitCXXTypeidExpr(E);
1778  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1779}
1780
1781LValue
1782CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1783  LValue LV = EmitLValue(E->getSubExpr());
1784  PushCXXTemporary(E->getTemporary(), LV.getAddress());
1785  return LV;
1786}
1787
1788LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1789  // Can only get l-value for message expression returning aggregate type
1790  RValue RV = EmitObjCMessageExpr(E);
1791  // FIXME: can this be volatile?
1792  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1793}
1794
1795llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1796                                             const ObjCIvarDecl *Ivar) {
1797  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1798}
1799
1800LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1801                                          llvm::Value *BaseValue,
1802                                          const ObjCIvarDecl *Ivar,
1803                                          unsigned CVRQualifiers) {
1804  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1805                                                   Ivar, CVRQualifiers);
1806}
1807
1808LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1809  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1810  llvm::Value *BaseValue = 0;
1811  const Expr *BaseExpr = E->getBase();
1812  Qualifiers BaseQuals;
1813  QualType ObjectTy;
1814  if (E->isArrow()) {
1815    BaseValue = EmitScalarExpr(BaseExpr);
1816    ObjectTy = BaseExpr->getType()->getPointeeType();
1817    BaseQuals = ObjectTy.getQualifiers();
1818  } else {
1819    LValue BaseLV = EmitLValue(BaseExpr);
1820    // FIXME: this isn't right for bitfields.
1821    BaseValue = BaseLV.getAddress();
1822    ObjectTy = BaseExpr->getType();
1823    BaseQuals = ObjectTy.getQualifiers();
1824  }
1825
1826  LValue LV =
1827    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1828                      BaseQuals.getCVRQualifiers());
1829  setObjCGCLValueClass(getContext(), E, LV);
1830  return LV;
1831}
1832
1833LValue
1834CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1835  // This is a special l-value that just issues sends when we load or store
1836  // through it.
1837  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1838}
1839
1840LValue CodeGenFunction::EmitObjCKVCRefLValue(
1841                                const ObjCImplicitSetterGetterRefExpr *E) {
1842  // This is a special l-value that just issues sends when we load or store
1843  // through it.
1844  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1845}
1846
1847LValue CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1848  return EmitUnsupportedLValue(E, "use of super");
1849}
1850
1851LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1852  // Can only get l-value for message expression returning aggregate type
1853  RValue RV = EmitAnyExprToTemp(E);
1854  // FIXME: can this be volatile?
1855  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1856}
1857
1858RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
1859                                 ReturnValueSlot ReturnValue,
1860                                 CallExpr::const_arg_iterator ArgBeg,
1861                                 CallExpr::const_arg_iterator ArgEnd,
1862                                 const Decl *TargetDecl) {
1863  // Get the actual function type. The callee type will always be a pointer to
1864  // function type or a block pointer type.
1865  assert(CalleeType->isFunctionPointerType() &&
1866         "Call must have function pointer type!");
1867
1868  CalleeType = getContext().getCanonicalType(CalleeType);
1869
1870  const FunctionType *FnType
1871    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
1872  QualType ResultType = FnType->getResultType();
1873
1874  CallArgList Args;
1875  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
1876
1877  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
1878                  Callee, ReturnValue, Args, TargetDecl);
1879}
1880
1881LValue CodeGenFunction::
1882EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
1883  llvm::Value *BaseV;
1884  if (E->getOpcode() == BinaryOperator::PtrMemI)
1885    BaseV = EmitScalarExpr(E->getLHS());
1886  else
1887    BaseV = EmitLValue(E->getLHS()).getAddress();
1888  const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(getLLVMContext());
1889  BaseV = Builder.CreateBitCast(BaseV, i8Ty);
1890  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
1891  llvm::Value *AddV = Builder.CreateInBoundsGEP(BaseV, OffsetV, "add.ptr");
1892
1893  QualType Ty = E->getRHS()->getType();
1894  Ty = Ty->getAs<MemberPointerType>()->getPointeeType();
1895
1896  const llvm::Type *PType = ConvertType(getContext().getPointerType(Ty));
1897  AddV = Builder.CreateBitCast(AddV, PType);
1898  return LValue::MakeAddr(AddV, MakeQualifiers(Ty));
1899}
1900
1901