CGExpr.cpp revision 3228f42b12c24c76f5d5ae4ebf80837b752d1683 
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    llvm::Value *Ptr = CreateTempAlloca(ConvertType(E->getType()));
45    EmitAggExpr(E, Ptr, /*VolatileDest=*/false);
46
47    // Get the pointer.
48    llvm::Value *FuncPtr = Builder.CreateStructGEP(Ptr, 0, "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(ConvertType(E->getType()), "agg.tmp");
91  return EmitAnyExpr(E, AggLoc, IsAggLocVolatile, /*IgnoreResult=*/false,
92                     IsInitializer);
93}
94
95RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr* E,
96                                                   QualType DestType,
97                                                   bool IsInitializer) {
98  bool ShouldDestroyTemporaries = false;
99  unsigned OldNumLiveTemporaries = 0;
100
101  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
102    E = DAE->getExpr();
103
104  if (const CXXExprWithTemporaries *TE = dyn_cast<CXXExprWithTemporaries>(E)) {
105    ShouldDestroyTemporaries = true;
106
107    // Keep track of the current cleanup stack depth.
108    OldNumLiveTemporaries = LiveTemporaries.size();
109
110    E = TE->getSubExpr();
111  }
112
113  RValue Val;
114  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
115    // Emit the expr as an lvalue.
116    LValue LV = EmitLValue(E);
117    if (LV.isSimple())
118      return RValue::get(LV.getAddress());
119    Val = EmitLoadOfLValue(LV, E->getType());
120
121    if (ShouldDestroyTemporaries) {
122      // Pop temporaries.
123      while (LiveTemporaries.size() > OldNumLiveTemporaries)
124        PopCXXTemporary();
125    }
126  } else {
127    const CXXRecordDecl *BaseClassDecl = 0;
128    const CXXRecordDecl *DerivedClassDecl = 0;
129
130    if (const CastExpr *CE =
131          dyn_cast<CastExpr>(E->IgnoreParenNoopCasts(getContext()))) {
132      if (CE->getCastKind() == CastExpr::CK_DerivedToBase) {
133        E = CE->getSubExpr();
134
135        BaseClassDecl =
136          cast<CXXRecordDecl>(CE->getType()->getAs<RecordType>()->getDecl());
137        DerivedClassDecl =
138          cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
139      }
140    }
141
142    Val = EmitAnyExprToTemp(E, /*IsAggLocVolatile=*/false,
143                            IsInitializer);
144
145    if (ShouldDestroyTemporaries) {
146      // Pop temporaries.
147      while (LiveTemporaries.size() > OldNumLiveTemporaries)
148        PopCXXTemporary();
149    }
150
151    if (IsInitializer) {
152      // We might have to destroy the temporary variable.
153      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
154        if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
155          if (!ClassDecl->hasTrivialDestructor()) {
156            const CXXDestructorDecl *Dtor =
157              ClassDecl->getDestructor(getContext());
158
159            {
160              DelayedCleanupBlock Scope(*this);
161              EmitCXXDestructorCall(Dtor, Dtor_Complete,
162                                    Val.getAggregateAddr());
163
164              // Make sure to jump to the exit block.
165              EmitBranch(Scope.getCleanupExitBlock());
166            }
167            if (Exceptions) {
168              EHCleanupBlock Cleanup(*this);
169              EmitCXXDestructorCall(Dtor, Dtor_Complete,
170                                    Val.getAggregateAddr());
171            }
172          }
173        }
174      }
175    }
176
177    // Check if need to perform the derived-to-base cast.
178    if (BaseClassDecl) {
179      llvm::Value *Derived = Val.getAggregateAddr();
180      llvm::Value *Base =
181        GetAddressOfBaseClass(Derived, DerivedClassDecl, BaseClassDecl,
182                              /*NullCheckValue=*/false);
183      return RValue::get(Base);
184    }
185  }
186
187  if (Val.isAggregate()) {
188    Val = RValue::get(Val.getAggregateAddr());
189  } else {
190    // Create a temporary variable that we can bind the reference to.
191    llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()),
192                                         "reftmp");
193    if (Val.isScalar())
194      EmitStoreOfScalar(Val.getScalarVal(), Temp, false, E->getType());
195    else
196      StoreComplexToAddr(Val.getComplexVal(), Temp, false);
197    Val = RValue::get(Temp);
198  }
199
200  return Val;
201}
202
203
204/// getAccessedFieldNo - Given an encoded value and a result number, return the
205/// input field number being accessed.
206unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
207                                             const llvm::Constant *Elts) {
208  if (isa<llvm::ConstantAggregateZero>(Elts))
209    return 0;
210
211  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
212}
213
214void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
215  if (!CatchUndefined)
216    return;
217
218  const llvm::IntegerType *Size_tTy
219    = llvm::IntegerType::get(VMContext, LLVMPointerWidth);
220  Address = Builder.CreateBitCast(Address, PtrToInt8Ty);
221
222  const llvm::Type *ResType[] = {
223    Size_tTy
224  };
225  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, ResType, 1);
226  const llvm::IntegerType *IntTy = cast<llvm::IntegerType>(
227    CGM.getTypes().ConvertType(CGM.getContext().IntTy));
228  // In time, people may want to control this and use a 1 here.
229  llvm::Value *Arg = llvm::ConstantInt::get(IntTy, 0);
230  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
231  llvm::BasicBlock *Cont = createBasicBlock();
232  llvm::BasicBlock *Check = createBasicBlock();
233  llvm::Value *NegativeOne = llvm::ConstantInt::get(Size_tTy, -1ULL);
234  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
235
236  EmitBlock(Check);
237  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
238                                        llvm::ConstantInt::get(Size_tTy, Size)),
239                       Cont, getTrapBB());
240  EmitBlock(Cont);
241}
242
243
244llvm::Value *CodeGenFunction::
245EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
246                        bool isInc, bool isPre) {
247  QualType ValTy = E->getSubExpr()->getType();
248  llvm::Value *InVal = EmitLoadOfLValue(LV, ValTy).getScalarVal();
249
250  int AmountVal = isInc ? 1 : -1;
251
252  if (ValTy->isPointerType() &&
253      ValTy->getAs<PointerType>()->isVariableArrayType()) {
254    // The amount of the addition/subtraction needs to account for the VLA size
255    ErrorUnsupported(E, "VLA pointer inc/dec");
256  }
257
258  llvm::Value *NextVal;
259  if (const llvm::PointerType *PT =
260      dyn_cast<llvm::PointerType>(InVal->getType())) {
261    llvm::Constant *Inc =
262    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), AmountVal);
263    if (!isa<llvm::FunctionType>(PT->getElementType())) {
264      QualType PTEE = ValTy->getPointeeType();
265      if (const ObjCInterfaceType *OIT =
266          dyn_cast<ObjCInterfaceType>(PTEE)) {
267        // Handle interface types, which are not represented with a concrete
268        // type.
269        int size = getContext().getTypeSize(OIT) / 8;
270        if (!isInc)
271          size = -size;
272        Inc = llvm::ConstantInt::get(Inc->getType(), size);
273        const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
274        InVal = Builder.CreateBitCast(InVal, i8Ty);
275        NextVal = Builder.CreateGEP(InVal, Inc, "add.ptr");
276        llvm::Value *lhs = LV.getAddress();
277        lhs = Builder.CreateBitCast(lhs, llvm::PointerType::getUnqual(i8Ty));
278        LV = LValue::MakeAddr(lhs, MakeQualifiers(ValTy));
279      } else
280        NextVal = Builder.CreateInBoundsGEP(InVal, Inc, "ptrincdec");
281    } else {
282      const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
283      NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp");
284      NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec");
285      NextVal = Builder.CreateBitCast(NextVal, InVal->getType());
286    }
287  } else if (InVal->getType() == llvm::Type::getInt1Ty(VMContext) && isInc) {
288    // Bool++ is an interesting case, due to promotion rules, we get:
289    // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 ->
290    // Bool = ((int)Bool+1) != 0
291    // An interesting aspect of this is that increment is always true.
292    // Decrement does not have this property.
293    NextVal = llvm::ConstantInt::getTrue(VMContext);
294  } else if (isa<llvm::IntegerType>(InVal->getType())) {
295    NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
296
297    // Signed integer overflow is undefined behavior.
298    if (ValTy->isSignedIntegerType())
299      NextVal = Builder.CreateNSWAdd(InVal, NextVal, isInc ? "inc" : "dec");
300    else
301      NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
302  } else {
303    // Add the inc/dec to the real part.
304    if (InVal->getType()->isFloatTy())
305      NextVal =
306      llvm::ConstantFP::get(VMContext,
307                            llvm::APFloat(static_cast<float>(AmountVal)));
308    else if (InVal->getType()->isDoubleTy())
309      NextVal =
310      llvm::ConstantFP::get(VMContext,
311                            llvm::APFloat(static_cast<double>(AmountVal)));
312    else {
313      llvm::APFloat F(static_cast<float>(AmountVal));
314      bool ignored;
315      F.convert(Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
316                &ignored);
317      NextVal = llvm::ConstantFP::get(VMContext, F);
318    }
319    NextVal = Builder.CreateFAdd(InVal, NextVal, isInc ? "inc" : "dec");
320  }
321
322  // Store the updated result through the lvalue.
323  if (LV.isBitfield())
324    EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy, &NextVal);
325  else
326    EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy);
327
328  // If this is a postinc, return the value read from memory, otherwise use the
329  // updated value.
330  return isPre ? NextVal : InVal;
331}
332
333
334CodeGenFunction::ComplexPairTy CodeGenFunction::
335EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
336                         bool isInc, bool isPre) {
337  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
338                                            LV.isVolatileQualified());
339
340  llvm::Value *NextVal;
341  if (isa<llvm::IntegerType>(InVal.first->getType())) {
342    uint64_t AmountVal = isInc ? 1 : -1;
343    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
344
345    // Add the inc/dec to the real part.
346    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
347  } else {
348    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
349    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
350    if (!isInc)
351      FVal.changeSign();
352    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
353
354    // Add the inc/dec to the real part.
355    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
356  }
357
358  ComplexPairTy IncVal(NextVal, InVal.second);
359
360  // Store the updated result through the lvalue.
361  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
362
363  // If this is a postinc, return the value read from memory, otherwise use the
364  // updated value.
365  return isPre ? IncVal : InVal;
366}
367
368
369//===----------------------------------------------------------------------===//
370//                         LValue Expression Emission
371//===----------------------------------------------------------------------===//
372
373RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
374  if (Ty->isVoidType())
375    return RValue::get(0);
376
377  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
378    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
379    llvm::Value *U = llvm::UndefValue::get(EltTy);
380    return RValue::getComplex(std::make_pair(U, U));
381  }
382
383  if (hasAggregateLLVMType(Ty)) {
384    const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
385    return RValue::getAggregate(llvm::UndefValue::get(LTy));
386  }
387
388  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
389}
390
391RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
392                                              const char *Name) {
393  ErrorUnsupported(E, Name);
394  return GetUndefRValue(E->getType());
395}
396
397LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
398                                              const char *Name) {
399  ErrorUnsupported(E, Name);
400  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
401  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
402                          MakeQualifiers(E->getType()));
403}
404
405LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
406  LValue LV = EmitLValue(E);
407  if (!isa<DeclRefExpr>(E) && !LV.isBitfield() && LV.isSimple())
408    EmitCheck(LV.getAddress(), getContext().getTypeSize(E->getType()) / 8);
409  return LV;
410}
411
412/// EmitLValue - Emit code to compute a designator that specifies the location
413/// of the expression.
414///
415/// This can return one of two things: a simple address or a bitfield reference.
416/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
417/// an LLVM pointer type.
418///
419/// If this returns a bitfield reference, nothing about the pointee type of the
420/// LLVM value is known: For example, it may not be a pointer to an integer.
421///
422/// If this returns a normal address, and if the lvalue's C type is fixed size,
423/// this method guarantees that the returned pointer type will point to an LLVM
424/// type of the same size of the lvalue's type.  If the lvalue has a variable
425/// length type, this is not possible.
426///
427LValue CodeGenFunction::EmitLValue(const Expr *E) {
428  switch (E->getStmtClass()) {
429  default: return EmitUnsupportedLValue(E, "l-value expression");
430
431  case Expr::ObjCIsaExprClass:
432    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
433  case Expr::BinaryOperatorClass:
434    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
435  case Expr::CallExprClass:
436  case Expr::CXXMemberCallExprClass:
437  case Expr::CXXOperatorCallExprClass:
438    return EmitCallExprLValue(cast<CallExpr>(E));
439  case Expr::VAArgExprClass:
440    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
441  case Expr::DeclRefExprClass:
442    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
443  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
444  case Expr::PredefinedExprClass:
445    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
446  case Expr::StringLiteralClass:
447    return EmitStringLiteralLValue(cast<StringLiteral>(E));
448  case Expr::ObjCEncodeExprClass:
449    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
450
451  case Expr::BlockDeclRefExprClass:
452    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
453
454  case Expr::CXXTemporaryObjectExprClass:
455  case Expr::CXXConstructExprClass:
456    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
457  case Expr::CXXBindTemporaryExprClass:
458    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
459  case Expr::CXXExprWithTemporariesClass:
460    return EmitCXXExprWithTemporariesLValue(cast<CXXExprWithTemporaries>(E));
461  case Expr::CXXZeroInitValueExprClass:
462    return EmitNullInitializationLValue(cast<CXXZeroInitValueExpr>(E));
463  case Expr::CXXDefaultArgExprClass:
464    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
465  case Expr::CXXTypeidExprClass:
466    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
467
468  case Expr::ObjCMessageExprClass:
469    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
470  case Expr::ObjCIvarRefExprClass:
471    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
472  case Expr::ObjCPropertyRefExprClass:
473    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
474  case Expr::ObjCImplicitSetterGetterRefExprClass:
475    return EmitObjCKVCRefLValue(cast<ObjCImplicitSetterGetterRefExpr>(E));
476  case Expr::ObjCSuperExprClass:
477    return EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
478
479  case Expr::StmtExprClass:
480    return EmitStmtExprLValue(cast<StmtExpr>(E));
481  case Expr::UnaryOperatorClass:
482    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
483  case Expr::ArraySubscriptExprClass:
484    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
485  case Expr::ExtVectorElementExprClass:
486    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
487  case Expr::MemberExprClass:
488    return EmitMemberExpr(cast<MemberExpr>(E));
489  case Expr::CompoundLiteralExprClass:
490    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
491  case Expr::ConditionalOperatorClass:
492    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
493  case Expr::ChooseExprClass:
494    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
495  case Expr::ImplicitCastExprClass:
496  case Expr::CStyleCastExprClass:
497  case Expr::CXXFunctionalCastExprClass:
498  case Expr::CXXStaticCastExprClass:
499  case Expr::CXXDynamicCastExprClass:
500  case Expr::CXXReinterpretCastExprClass:
501  case Expr::CXXConstCastExprClass:
502    return EmitCastLValue(cast<CastExpr>(E));
503  }
504}
505
506llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
507                                               QualType Ty) {
508  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
509  if (Volatile)
510    Load->setVolatile(true);
511
512  // Bool can have different representation in memory than in registers.
513  llvm::Value *V = Load;
514  if (Ty->isBooleanType())
515    if (V->getType() != llvm::Type::getInt1Ty(VMContext))
516      V = Builder.CreateTrunc(V, llvm::Type::getInt1Ty(VMContext), "tobool");
517
518  return V;
519}
520
521void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
522                                        bool Volatile, QualType Ty) {
523
524  if (Ty->isBooleanType()) {
525    // Bool can have different representation in memory than in registers.
526    const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
527    Value = Builder.CreateIntCast(Value, DstPtr->getElementType(), false);
528  }
529  Builder.CreateStore(Value, Addr, Volatile);
530}
531
532/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
533/// method emits the address of the lvalue, then loads the result as an rvalue,
534/// returning the rvalue.
535RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
536  if (LV.isObjCWeak()) {
537    // load of a __weak object.
538    llvm::Value *AddrWeakObj = LV.getAddress();
539    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
540                                                             AddrWeakObj));
541  }
542
543  if (LV.isSimple()) {
544    llvm::Value *Ptr = LV.getAddress();
545    const llvm::Type *EltTy =
546      cast<llvm::PointerType>(Ptr->getType())->getElementType();
547
548    // Simple scalar l-value.
549    if (EltTy->isSingleValueType())
550      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
551                                          ExprType));
552
553    assert(ExprType->isFunctionType() && "Unknown scalar value");
554    return RValue::get(Ptr);
555  }
556
557  if (LV.isVectorElt()) {
558    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
559                                          LV.isVolatileQualified(), "tmp");
560    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
561                                                    "vecext"));
562  }
563
564  // If this is a reference to a subset of the elements of a vector, either
565  // shuffle the input or extract/insert them as appropriate.
566  if (LV.isExtVectorElt())
567    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
568
569  if (LV.isBitfield())
570    return EmitLoadOfBitfieldLValue(LV, ExprType);
571
572  if (LV.isPropertyRef())
573    return EmitLoadOfPropertyRefLValue(LV, ExprType);
574
575  assert(LV.isKVCRef() && "Unknown LValue type!");
576  return EmitLoadOfKVCRefLValue(LV, ExprType);
577}
578
579RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
580                                                 QualType ExprType) {
581  unsigned StartBit = LV.getBitfieldStartBit();
582  unsigned BitfieldSize = LV.getBitfieldSize();
583  llvm::Value *Ptr = LV.getBitfieldAddr();
584
585  const llvm::Type *EltTy =
586    cast<llvm::PointerType>(Ptr->getType())->getElementType();
587  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
588
589  // In some cases the bitfield may straddle two memory locations.  Currently we
590  // load the entire bitfield, then do the magic to sign-extend it if
591  // necessary. This results in somewhat more code than necessary for the common
592  // case (one load), since two shifts accomplish both the masking and sign
593  // extension.
594  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
595  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
596
597  // Shift to proper location.
598  if (StartBit)
599    Val = Builder.CreateLShr(Val, StartBit, "bf.lo");
600
601  // Mask off unused bits.
602  llvm::Constant *LowMask = llvm::ConstantInt::get(VMContext,
603                                llvm::APInt::getLowBitsSet(EltTySize, LowBits));
604  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
605
606  // Fetch the high bits if necessary.
607  if (LowBits < BitfieldSize) {
608    unsigned HighBits = BitfieldSize - LowBits;
609    llvm::Value *HighPtr = Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
610                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
611    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
612                                              LV.isVolatileQualified(),
613                                              "tmp");
614
615    // Mask off unused bits.
616    llvm::Constant *HighMask = llvm::ConstantInt::get(VMContext,
617                               llvm::APInt::getLowBitsSet(EltTySize, HighBits));
618    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
619
620    // Shift to proper location and or in to bitfield value.
621    HighVal = Builder.CreateShl(HighVal, LowBits);
622    Val = Builder.CreateOr(Val, HighVal, "bf.val");
623  }
624
625  // Sign extend if necessary.
626  if (LV.isBitfieldSigned()) {
627    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
628                                                    EltTySize - BitfieldSize);
629    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
630                             ExtraBits, "bf.val.sext");
631  }
632
633  // The bitfield type and the normal type differ when the storage sizes differ
634  // (currently just _Bool).
635  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
636
637  return RValue::get(Val);
638}
639
640RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
641                                                    QualType ExprType) {
642  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
643}
644
645RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
646                                               QualType ExprType) {
647  return EmitObjCPropertyGet(LV.getKVCRefExpr());
648}
649
650// If this is a reference to a subset of the elements of a vector, create an
651// appropriate shufflevector.
652RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
653                                                         QualType ExprType) {
654  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
655                                        LV.isVolatileQualified(), "tmp");
656
657  const llvm::Constant *Elts = LV.getExtVectorElts();
658
659  // If the result of the expression is a non-vector type, we must be extracting
660  // a single element.  Just codegen as an extractelement.
661  const VectorType *ExprVT = ExprType->getAs<VectorType>();
662  if (!ExprVT) {
663    unsigned InIdx = getAccessedFieldNo(0, Elts);
664    llvm::Value *Elt = llvm::ConstantInt::get(
665                                      llvm::Type::getInt32Ty(VMContext), InIdx);
666    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
667  }
668
669  // Always use shuffle vector to try to retain the original program structure
670  unsigned NumResultElts = ExprVT->getNumElements();
671
672  llvm::SmallVector<llvm::Constant*, 4> Mask;
673  for (unsigned i = 0; i != NumResultElts; ++i) {
674    unsigned InIdx = getAccessedFieldNo(i, Elts);
675    Mask.push_back(llvm::ConstantInt::get(
676                                     llvm::Type::getInt32Ty(VMContext), InIdx));
677  }
678
679  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
680  Vec = Builder.CreateShuffleVector(Vec,
681                                    llvm::UndefValue::get(Vec->getType()),
682                                    MaskV, "tmp");
683  return RValue::get(Vec);
684}
685
686
687
688/// EmitStoreThroughLValue - Store the specified rvalue into the specified
689/// lvalue, where both are guaranteed to the have the same type, and that type
690/// is 'Ty'.
691void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
692                                             QualType Ty) {
693  if (!Dst.isSimple()) {
694    if (Dst.isVectorElt()) {
695      // Read/modify/write the vector, inserting the new element.
696      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
697                                            Dst.isVolatileQualified(), "tmp");
698      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
699                                        Dst.getVectorIdx(), "vecins");
700      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
701      return;
702    }
703
704    // If this is an update of extended vector elements, insert them as
705    // appropriate.
706    if (Dst.isExtVectorElt())
707      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
708
709    if (Dst.isBitfield())
710      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
711
712    if (Dst.isPropertyRef())
713      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
714
715    assert(Dst.isKVCRef() && "Unknown LValue type");
716    return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
717  }
718
719  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
720    // load of a __weak object.
721    llvm::Value *LvalueDst = Dst.getAddress();
722    llvm::Value *src = Src.getScalarVal();
723     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
724    return;
725  }
726
727  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
728    // load of a __strong object.
729    llvm::Value *LvalueDst = Dst.getAddress();
730    llvm::Value *src = Src.getScalarVal();
731    if (Dst.isObjCIvar()) {
732      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
733      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
734      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
735      llvm::Value *dst = RHS;
736      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
737      llvm::Value *LHS =
738        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
739      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
740      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
741                                              BytesBetween);
742    } else if (Dst.isGlobalObjCRef())
743      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
744    else
745      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
746    return;
747  }
748
749  assert(Src.isScalar() && "Can't emit an agg store with this method");
750  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
751                    Dst.isVolatileQualified(), Ty);
752}
753
754void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
755                                                     QualType Ty,
756                                                     llvm::Value **Result) {
757  unsigned StartBit = Dst.getBitfieldStartBit();
758  unsigned BitfieldSize = Dst.getBitfieldSize();
759  llvm::Value *Ptr = Dst.getBitfieldAddr();
760
761  const llvm::Type *EltTy =
762    cast<llvm::PointerType>(Ptr->getType())->getElementType();
763  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
764
765  // Get the new value, cast to the appropriate type and masked to exactly the
766  // size of the bit-field.
767  llvm::Value *SrcVal = Src.getScalarVal();
768  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
769  llvm::Constant *Mask = llvm::ConstantInt::get(VMContext,
770                           llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
771  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
772
773  // Return the new value of the bit-field, if requested.
774  if (Result) {
775    // Cast back to the proper type for result.
776    const llvm::Type *SrcTy = SrcVal->getType();
777    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
778                                                  "bf.reload.val");
779
780    // Sign extend if necessary.
781    if (Dst.isBitfieldSigned()) {
782      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
783      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
784                                                      SrcTySize - BitfieldSize);
785      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
786                                    ExtraBits, "bf.reload.sext");
787    }
788
789    *Result = SrcTrunc;
790  }
791
792  // In some cases the bitfield may straddle two memory locations.  Emit the low
793  // part first and check to see if the high needs to be done.
794  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
795  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
796                                           "bf.prev.low");
797
798  // Compute the mask for zero-ing the low part of this bitfield.
799  llvm::Constant *InvMask =
800    llvm::ConstantInt::get(VMContext,
801             ~llvm::APInt::getBitsSet(EltTySize, StartBit, StartBit + LowBits));
802
803  // Compute the new low part as
804  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
805  // with the shift of NewVal implicitly stripping the high bits.
806  llvm::Value *NewLowVal =
807    Builder.CreateShl(NewVal, StartBit, "bf.value.lo");
808  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
809  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
810
811  // Write back.
812  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
813
814  // If the low part doesn't cover the bitfield emit a high part.
815  if (LowBits < BitfieldSize) {
816    unsigned HighBits = BitfieldSize - LowBits;
817    llvm::Value *HighPtr =  Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
818                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
819    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
820                                              Dst.isVolatileQualified(),
821                                              "bf.prev.hi");
822
823    // Compute the mask for zero-ing the high part of this bitfield.
824    llvm::Constant *InvMask =
825      llvm::ConstantInt::get(VMContext, ~llvm::APInt::getLowBitsSet(EltTySize,
826                               HighBits));
827
828    // Compute the new high part as
829    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
830    // where the high bits of NewVal have already been cleared and the
831    // shift stripping the low bits.
832    llvm::Value *NewHighVal =
833      Builder.CreateLShr(NewVal, LowBits, "bf.value.high");
834    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
835    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
836
837    // Write back.
838    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
839  }
840}
841
842void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
843                                                        LValue Dst,
844                                                        QualType Ty) {
845  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
846}
847
848void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
849                                                   LValue Dst,
850                                                   QualType Ty) {
851  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
852}
853
854void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
855                                                               LValue Dst,
856                                                               QualType Ty) {
857  // This access turns into a read/modify/write of the vector.  Load the input
858  // value now.
859  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
860                                        Dst.isVolatileQualified(), "tmp");
861  const llvm::Constant *Elts = Dst.getExtVectorElts();
862
863  llvm::Value *SrcVal = Src.getScalarVal();
864
865  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
866    unsigned NumSrcElts = VTy->getNumElements();
867    unsigned NumDstElts =
868       cast<llvm::VectorType>(Vec->getType())->getNumElements();
869    if (NumDstElts == NumSrcElts) {
870      // Use shuffle vector is the src and destination are the same number of
871      // elements and restore the vector mask since it is on the side it will be
872      // stored.
873      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
874      for (unsigned i = 0; i != NumSrcElts; ++i) {
875        unsigned InIdx = getAccessedFieldNo(i, Elts);
876        Mask[InIdx] = llvm::ConstantInt::get(
877                                          llvm::Type::getInt32Ty(VMContext), i);
878      }
879
880      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
881      Vec = Builder.CreateShuffleVector(SrcVal,
882                                        llvm::UndefValue::get(Vec->getType()),
883                                        MaskV, "tmp");
884    } else if (NumDstElts > NumSrcElts) {
885      // Extended the source vector to the same length and then shuffle it
886      // into the destination.
887      // FIXME: since we're shuffling with undef, can we just use the indices
888      //        into that?  This could be simpler.
889      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
890      const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
891      unsigned i;
892      for (i = 0; i != NumSrcElts; ++i)
893        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
894      for (; i != NumDstElts; ++i)
895        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
896      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
897                                                        ExtMask.size());
898      llvm::Value *ExtSrcVal =
899        Builder.CreateShuffleVector(SrcVal,
900                                    llvm::UndefValue::get(SrcVal->getType()),
901                                    ExtMaskV, "tmp");
902      // build identity
903      llvm::SmallVector<llvm::Constant*, 4> Mask;
904      for (unsigned i = 0; i != NumDstElts; ++i)
905        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
906
907      // modify when what gets shuffled in
908      for (unsigned i = 0; i != NumSrcElts; ++i) {
909        unsigned Idx = getAccessedFieldNo(i, Elts);
910        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
911      }
912      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
913      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
914    } else {
915      // We should never shorten the vector
916      assert(0 && "unexpected shorten vector length");
917    }
918  } else {
919    // If the Src is a scalar (not a vector) it must be updating one element.
920    unsigned InIdx = getAccessedFieldNo(0, Elts);
921    const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
922    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
923    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
924  }
925
926  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
927}
928
929// setObjCGCLValueClass - sets class of he lvalue for the purpose of
930// generating write-barries API. It is currently a global, ivar,
931// or neither.
932static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
933                                 LValue &LV) {
934  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
935    return;
936
937  if (isa<ObjCIvarRefExpr>(E)) {
938    LV.SetObjCIvar(LV, true);
939    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
940    LV.setBaseIvarExp(Exp->getBase());
941    LV.SetObjCArray(LV, E->getType()->isArrayType());
942    return;
943  }
944
945  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
946    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
947      if ((VD->isBlockVarDecl() && !VD->hasLocalStorage()) ||
948          VD->isFileVarDecl())
949        LV.SetGlobalObjCRef(LV, true);
950    }
951    LV.SetObjCArray(LV, E->getType()->isArrayType());
952    return;
953  }
954
955  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
956    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
957    return;
958  }
959
960  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
961    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
962    if (LV.isObjCIvar()) {
963      // If cast is to a structure pointer, follow gcc's behavior and make it
964      // a non-ivar write-barrier.
965      QualType ExpTy = E->getType();
966      if (ExpTy->isPointerType())
967        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
968      if (ExpTy->isRecordType())
969        LV.SetObjCIvar(LV, false);
970    }
971    return;
972  }
973  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
974    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
975    return;
976  }
977
978  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
979    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
980    return;
981  }
982
983  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
984    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
985    if (LV.isObjCIvar() && !LV.isObjCArray())
986      // Using array syntax to assigning to what an ivar points to is not
987      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
988      LV.SetObjCIvar(LV, false);
989    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
990      // Using array syntax to assigning to what global points to is not
991      // same as assigning to the global itself. {id *G;} G[i] = 0;
992      LV.SetGlobalObjCRef(LV, false);
993    return;
994  }
995
996  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
997    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
998    // We don't know if member is an 'ivar', but this flag is looked at
999    // only in the context of LV.isObjCIvar().
1000    LV.SetObjCArray(LV, E->getType()->isArrayType());
1001    return;
1002  }
1003}
1004
1005static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1006                                      const Expr *E, const VarDecl *VD) {
1007  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1008         "Var decl must have external storage or be a file var decl!");
1009
1010  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1011  if (VD->getType()->isReferenceType())
1012    V = CGF.Builder.CreateLoad(V, "tmp");
1013  LValue LV = LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1014  setObjCGCLValueClass(CGF.getContext(), E, LV);
1015  return LV;
1016}
1017
1018static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1019                                      const Expr *E, const FunctionDecl *FD) {
1020  llvm::Value* V = CGF.CGM.GetAddrOfFunction(FD);
1021  if (!FD->hasPrototype()) {
1022    if (const FunctionProtoType *Proto =
1023            FD->getType()->getAs<FunctionProtoType>()) {
1024      // Ugly case: for a K&R-style definition, the type of the definition
1025      // isn't the same as the type of a use.  Correct for this with a
1026      // bitcast.
1027      QualType NoProtoType =
1028          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1029      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1030      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1031    }
1032  }
1033  return LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1034}
1035
1036LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1037  const NamedDecl *ND = E->getDecl();
1038
1039  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1040
1041    // Check if this is a global variable.
1042    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1043      return EmitGlobalVarDeclLValue(*this, E, VD);
1044
1045    bool NonGCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
1046
1047    llvm::Value *V = LocalDeclMap[VD];
1048    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1049
1050    Qualifiers Quals = MakeQualifiers(E->getType());
1051    // local variables do not get their gc attribute set.
1052    // local static?
1053    if (NonGCable) Quals.removeObjCGCAttr();
1054
1055    if (VD->hasAttr<BlocksAttr>()) {
1056      V = Builder.CreateStructGEP(V, 1, "forwarding");
1057      V = Builder.CreateLoad(V);
1058      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
1059                                  VD->getNameAsString());
1060    }
1061    if (VD->getType()->isReferenceType())
1062      V = Builder.CreateLoad(V, "tmp");
1063    LValue LV = LValue::MakeAddr(V, Quals);
1064    LValue::SetObjCNonGC(LV, NonGCable);
1065    setObjCGCLValueClass(getContext(), E, LV);
1066    return LV;
1067  }
1068
1069  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1070    return EmitFunctionDeclLValue(*this, E, FD);
1071
1072  if (E->getQualifier()) {
1073    // FIXME: the qualifier check does not seem sufficient here
1074    return EmitPointerToDataMemberLValue(cast<FieldDecl>(ND));
1075  }
1076
1077  assert(false && "Unhandled DeclRefExpr");
1078
1079  // an invalid LValue, but the assert will
1080  // ensure that this point is never reached.
1081  return LValue();
1082}
1083
1084LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1085  return LValue::MakeAddr(GetAddrOfBlockDecl(E), MakeQualifiers(E->getType()));
1086}
1087
1088LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1089  // __extension__ doesn't affect lvalue-ness.
1090  if (E->getOpcode() == UnaryOperator::Extension)
1091    return EmitLValue(E->getSubExpr());
1092
1093  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1094  switch (E->getOpcode()) {
1095  default: assert(0 && "Unknown unary operator lvalue!");
1096  case UnaryOperator::Deref: {
1097    QualType T = E->getSubExpr()->getType()->getPointeeType();
1098    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1099
1100    Qualifiers Quals = MakeQualifiers(T);
1101    Quals.setAddressSpace(ExprTy.getAddressSpace());
1102
1103    LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()), Quals);
1104    // We should not generate __weak write barrier on indirect reference
1105    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1106    // But, we continue to generate __strong write barrier on indirect write
1107    // into a pointer to object.
1108    if (getContext().getLangOptions().ObjC1 &&
1109        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1110        LV.isObjCWeak())
1111      LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1112    return LV;
1113  }
1114  case UnaryOperator::Real:
1115  case UnaryOperator::Imag: {
1116    LValue LV = EmitLValue(E->getSubExpr());
1117    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
1118    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
1119                                                    Idx, "idx"),
1120                            MakeQualifiers(ExprTy));
1121  }
1122  case UnaryOperator::PreInc:
1123  case UnaryOperator::PreDec: {
1124    LValue LV = EmitLValue(E->getSubExpr());
1125    bool isInc = E->getOpcode() == UnaryOperator::PreInc;
1126
1127    if (E->getType()->isAnyComplexType())
1128      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1129    else
1130      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1131    return LV;
1132  }
1133  }
1134}
1135
1136LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1137  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E),
1138                          Qualifiers());
1139}
1140
1141LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1142  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1143                          Qualifiers());
1144}
1145
1146
1147LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
1148  std::string GlobalVarName;
1149
1150  switch (Type) {
1151  default: assert(0 && "Invalid type");
1152  case PredefinedExpr::Func:
1153    GlobalVarName = "__func__.";
1154    break;
1155  case PredefinedExpr::Function:
1156    GlobalVarName = "__FUNCTION__.";
1157    break;
1158  case PredefinedExpr::PrettyFunction:
1159    GlobalVarName = "__PRETTY_FUNCTION__.";
1160    break;
1161  }
1162
1163  llvm::StringRef FnName = CurFn->getName();
1164  if (FnName.startswith("\01"))
1165    FnName = FnName.substr(1);
1166  GlobalVarName += FnName;
1167
1168  std::string FunctionName =
1169    PredefinedExpr::ComputeName(getContext(), (PredefinedExpr::IdentType)Type,
1170                                CurCodeDecl);
1171
1172  llvm::Constant *C =
1173    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1174  return LValue::MakeAddr(C, Qualifiers());
1175}
1176
1177LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1178  switch (E->getIdentType()) {
1179  default:
1180    return EmitUnsupportedLValue(E, "predefined expression");
1181  case PredefinedExpr::Func:
1182  case PredefinedExpr::Function:
1183  case PredefinedExpr::PrettyFunction:
1184    return EmitPredefinedFunctionName(E->getIdentType());
1185  }
1186}
1187
1188llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1189  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1190
1191  // If we are not optimzing, don't collapse all calls to trap in the function
1192  // to the same call, that way, in the debugger they can see which operation
1193  // did in fact fail.  If we are optimizing, we collpase all call to trap down
1194  // to just one per function to save on codesize.
1195  if (GCO.OptimizationLevel
1196      && TrapBB)
1197    return TrapBB;
1198
1199  llvm::BasicBlock *Cont = 0;
1200  if (HaveInsertPoint()) {
1201    Cont = createBasicBlock("cont");
1202    EmitBranch(Cont);
1203  }
1204  TrapBB = createBasicBlock("trap");
1205  EmitBlock(TrapBB);
1206
1207  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1208  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1209  TrapCall->setDoesNotReturn();
1210  TrapCall->setDoesNotThrow();
1211  Builder.CreateUnreachable();
1212
1213  if (Cont)
1214    EmitBlock(Cont);
1215  return TrapBB;
1216}
1217
1218LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1219  // The index must always be an integer, which is not an aggregate.  Emit it.
1220  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1221  QualType IdxTy  = E->getIdx()->getType();
1222  bool IdxSigned = IdxTy->isSignedIntegerType();
1223
1224  // If the base is a vector type, then we are forming a vector element lvalue
1225  // with this subscript.
1226  if (E->getBase()->getType()->isVectorType()) {
1227    // Emit the vector as an lvalue to get its address.
1228    LValue LHS = EmitLValue(E->getBase());
1229    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1230    Idx = Builder.CreateIntCast(Idx,
1231                          llvm::Type::getInt32Ty(VMContext), IdxSigned, "vidx");
1232    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1233                                 E->getBase()->getType().getCVRQualifiers());
1234  }
1235
1236  // The base must be a pointer, which is not an aggregate.  Emit it.
1237  llvm::Value *Base = EmitScalarExpr(E->getBase());
1238
1239  // Extend or truncate the index type to 32 or 64-bits.
1240  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1241  if (IdxBitwidth != LLVMPointerWidth)
1242    Idx = Builder.CreateIntCast(Idx,
1243                            llvm::IntegerType::get(VMContext, LLVMPointerWidth),
1244                                IdxSigned, "idxprom");
1245
1246  // FIXME: As llvm implements the object size checking, this can come out.
1247  if (CatchUndefined) {
1248    if (const ImplicitCastExpr *ICE=dyn_cast<ImplicitCastExpr>(E->getBase())) {
1249      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1250        if (ICE->getCastKind() == CastExpr::CK_ArrayToPointerDecay) {
1251          if (const ConstantArrayType *CAT
1252              = getContext().getAsConstantArrayType(DRE->getType())) {
1253            llvm::APInt Size = CAT->getSize();
1254            llvm::BasicBlock *Cont = createBasicBlock("cont");
1255            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1256                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1257                                 Cont, getTrapBB());
1258            EmitBlock(Cont);
1259          }
1260        }
1261      }
1262    }
1263  }
1264
1265  // We know that the pointer points to a type of the correct size, unless the
1266  // size is a VLA or Objective-C interface.
1267  llvm::Value *Address = 0;
1268  if (const VariableArrayType *VAT =
1269        getContext().getAsVariableArrayType(E->getType())) {
1270    llvm::Value *VLASize = GetVLASize(VAT);
1271
1272    Idx = Builder.CreateMul(Idx, VLASize);
1273
1274    QualType BaseType = getContext().getBaseElementType(VAT);
1275
1276    CharUnits BaseTypeSize = getContext().getTypeSizeInChars(BaseType);
1277    Idx = Builder.CreateUDiv(Idx,
1278                             llvm::ConstantInt::get(Idx->getType(),
1279                                 BaseTypeSize.getQuantity()));
1280    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1281  } else if (const ObjCInterfaceType *OIT =
1282             dyn_cast<ObjCInterfaceType>(E->getType())) {
1283    llvm::Value *InterfaceSize =
1284      llvm::ConstantInt::get(Idx->getType(),
1285          getContext().getTypeSizeInChars(OIT).getQuantity());
1286
1287    Idx = Builder.CreateMul(Idx, InterfaceSize);
1288
1289    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1290    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1291                                Idx, "arrayidx");
1292    Address = Builder.CreateBitCast(Address, Base->getType());
1293  } else {
1294    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1295  }
1296
1297  QualType T = E->getBase()->getType()->getPointeeType();
1298  assert(!T.isNull() &&
1299         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1300
1301  Qualifiers Quals = MakeQualifiers(T);
1302  Quals.setAddressSpace(E->getBase()->getType().getAddressSpace());
1303
1304  LValue LV = LValue::MakeAddr(Address, Quals);
1305  if (getContext().getLangOptions().ObjC1 &&
1306      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1307    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1308    setObjCGCLValueClass(getContext(), E, LV);
1309  }
1310  return LV;
1311}
1312
1313static
1314llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1315                                       llvm::SmallVector<unsigned, 4> &Elts) {
1316  llvm::SmallVector<llvm::Constant*, 4> CElts;
1317
1318  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1319    CElts.push_back(llvm::ConstantInt::get(
1320                                   llvm::Type::getInt32Ty(VMContext), Elts[i]));
1321
1322  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1323}
1324
1325LValue CodeGenFunction::
1326EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1327  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1328
1329  // Emit the base vector as an l-value.
1330  LValue Base;
1331
1332  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1333  if (E->isArrow()) {
1334    // If it is a pointer to a vector, emit the address and form an lvalue with
1335    // it.
1336    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1337    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1338    Qualifiers Quals = MakeQualifiers(PT->getPointeeType());
1339    Quals.removeObjCGCAttr();
1340    Base = LValue::MakeAddr(Ptr, Quals);
1341  } else if (E->getBase()->isLvalue(getContext()) == Expr::LV_Valid) {
1342    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1343    // emit the base as an lvalue.
1344    assert(E->getBase()->getType()->isVectorType());
1345    Base = EmitLValue(E->getBase());
1346  } else {
1347    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1348    assert(E->getBase()->getType()->getAs<VectorType>() &&
1349           "Result must be a vector");
1350    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1351
1352    // Store the vector to memory (because LValue wants an address).
1353    llvm::Value *VecMem =CreateTempAlloca(ConvertType(E->getBase()->getType()));
1354    Builder.CreateStore(Vec, VecMem);
1355    Base = LValue::MakeAddr(VecMem, Qualifiers());
1356  }
1357
1358  // Encode the element access list into a vector of unsigned indices.
1359  llvm::SmallVector<unsigned, 4> Indices;
1360  E->getEncodedElementAccess(Indices);
1361
1362  if (Base.isSimple()) {
1363    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1364    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1365                                    Base.getVRQualifiers());
1366  }
1367  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1368
1369  llvm::Constant *BaseElts = Base.getExtVectorElts();
1370  llvm::SmallVector<llvm::Constant *, 4> CElts;
1371
1372  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1373    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1374      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1375    else
1376      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1377  }
1378  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1379  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1380                                  Base.getVRQualifiers());
1381}
1382
1383LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1384  bool isUnion = false;
1385  bool isNonGC = false;
1386  Expr *BaseExpr = E->getBase();
1387  llvm::Value *BaseValue = NULL;
1388  Qualifiers BaseQuals;
1389
1390  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1391  if (E->isArrow()) {
1392    BaseValue = EmitScalarExpr(BaseExpr);
1393    const PointerType *PTy =
1394      BaseExpr->getType()->getAs<PointerType>();
1395    if (PTy->getPointeeType()->isUnionType())
1396      isUnion = true;
1397    BaseQuals = PTy->getPointeeType().getQualifiers();
1398  } else if (isa<ObjCPropertyRefExpr>(BaseExpr->IgnoreParens()) ||
1399             isa<ObjCImplicitSetterGetterRefExpr>(
1400               BaseExpr->IgnoreParens())) {
1401    RValue RV = EmitObjCPropertyGet(BaseExpr);
1402    BaseValue = RV.getAggregateAddr();
1403    if (BaseExpr->getType()->isUnionType())
1404      isUnion = true;
1405    BaseQuals = BaseExpr->getType().getQualifiers();
1406  } else {
1407    LValue BaseLV = EmitLValue(BaseExpr);
1408    if (BaseLV.isNonGC())
1409      isNonGC = true;
1410    // FIXME: this isn't right for bitfields.
1411    BaseValue = BaseLV.getAddress();
1412    QualType BaseTy = BaseExpr->getType();
1413    if (BaseTy->isUnionType())
1414      isUnion = true;
1415    BaseQuals = BaseTy.getQualifiers();
1416  }
1417
1418  NamedDecl *ND = E->getMemberDecl();
1419  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1420    LValue LV = EmitLValueForField(BaseValue, Field, isUnion,
1421                                   BaseQuals.getCVRQualifiers());
1422    LValue::SetObjCNonGC(LV, isNonGC);
1423    setObjCGCLValueClass(getContext(), E, LV);
1424    return LV;
1425  }
1426
1427  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1428    return EmitGlobalVarDeclLValue(*this, E, VD);
1429
1430  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1431    return EmitFunctionDeclLValue(*this, E, FD);
1432
1433  assert(false && "Unhandled member declaration!");
1434  return LValue();
1435}
1436
1437LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
1438                                              const FieldDecl* Field,
1439                                              unsigned CVRQualifiers) {
1440  CodeGenTypes::BitFieldInfo Info = CGM.getTypes().getBitFieldInfo(Field);
1441
1442  // FIXME: CodeGenTypes should expose a method to get the appropriate type for
1443  // FieldTy (the appropriate type is ABI-dependent).
1444  const llvm::Type *FieldTy =
1445    CGM.getTypes().ConvertTypeForMem(Field->getType());
1446  const llvm::PointerType *BaseTy =
1447  cast<llvm::PointerType>(BaseValue->getType());
1448  unsigned AS = BaseTy->getAddressSpace();
1449  BaseValue = Builder.CreateBitCast(BaseValue,
1450                                    llvm::PointerType::get(FieldTy, AS),
1451                                    "tmp");
1452
1453  llvm::Value *Idx =
1454    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), Info.FieldNo);
1455  llvm::Value *V = Builder.CreateGEP(BaseValue, Idx, "tmp");
1456
1457  return LValue::MakeBitfield(V, Info.Start, Info.Size,
1458                              Field->getType()->isSignedIntegerType(),
1459                            Field->getType().getCVRQualifiers()|CVRQualifiers);
1460}
1461
1462LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
1463                                           const FieldDecl* Field,
1464                                           bool isUnion,
1465                                           unsigned CVRQualifiers) {
1466  if (Field->isBitField())
1467    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1468
1469  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
1470  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1471
1472  // Match union field type.
1473  if (isUnion) {
1474    const llvm::Type *FieldTy =
1475      CGM.getTypes().ConvertTypeForMem(Field->getType());
1476    const llvm::PointerType * BaseTy =
1477      cast<llvm::PointerType>(BaseValue->getType());
1478    unsigned AS = BaseTy->getAddressSpace();
1479    V = Builder.CreateBitCast(V,
1480                              llvm::PointerType::get(FieldTy, AS),
1481                              "tmp");
1482  }
1483  if (Field->getType()->isReferenceType())
1484    V = Builder.CreateLoad(V, "tmp");
1485
1486  Qualifiers Quals = MakeQualifiers(Field->getType());
1487  Quals.addCVRQualifiers(CVRQualifiers);
1488  // __weak attribute on a field is ignored.
1489  if (Quals.getObjCGCAttr() == Qualifiers::Weak)
1490    Quals.removeObjCGCAttr();
1491
1492  return LValue::MakeAddr(V, Quals);
1493}
1494
1495LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1496  const llvm::Type *LTy = ConvertType(E->getType());
1497  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
1498
1499  const Expr* InitExpr = E->getInitializer();
1500  LValue Result = LValue::MakeAddr(DeclPtr, MakeQualifiers(E->getType()));
1501
1502  if (E->getType()->isComplexType())
1503    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1504  else if (hasAggregateLLVMType(E->getType()))
1505    EmitAnyExpr(InitExpr, DeclPtr, false);
1506  else
1507    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1508
1509  return Result;
1510}
1511
1512LValue
1513CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator* E) {
1514  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
1515    if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1516      Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1517      if (Live)
1518        return EmitLValue(Live);
1519    }
1520
1521    if (!E->getLHS())
1522      return EmitUnsupportedLValue(E, "conditional operator with missing LHS");
1523
1524    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1525    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1526    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1527
1528    EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1529
1530    EmitBlock(LHSBlock);
1531
1532    LValue LHS = EmitLValue(E->getLHS());
1533    if (!LHS.isSimple())
1534      return EmitUnsupportedLValue(E, "conditional operator");
1535
1536    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1537    Builder.CreateStore(LHS.getAddress(), Temp);
1538    EmitBranch(ContBlock);
1539
1540    EmitBlock(RHSBlock);
1541    LValue RHS = EmitLValue(E->getRHS());
1542    if (!RHS.isSimple())
1543      return EmitUnsupportedLValue(E, "conditional operator");
1544
1545    Builder.CreateStore(RHS.getAddress(), Temp);
1546    EmitBranch(ContBlock);
1547
1548    EmitBlock(ContBlock);
1549
1550    Temp = Builder.CreateLoad(Temp, "lv");
1551    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1552  }
1553
1554  // ?: here should be an aggregate.
1555  assert((hasAggregateLLVMType(E->getType()) &&
1556          !E->getType()->isAnyComplexType()) &&
1557         "Unexpected conditional operator!");
1558
1559  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1560  EmitAggExpr(E, Temp, false);
1561
1562  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1563}
1564
1565/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1566/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1567/// otherwise if a cast is needed by the code generator in an lvalue context,
1568/// then it must mean that we need the address of an aggregate in order to
1569/// access one of its fields.  This can happen for all the reasons that casts
1570/// are permitted with aggregate result, including noop aggregate casts, and
1571/// cast from scalar to union.
1572LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1573  switch (E->getCastKind()) {
1574  default:
1575    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1576
1577  case CastExpr::CK_Dynamic: {
1578    LValue LV = EmitLValue(E->getSubExpr());
1579    llvm::Value *V = LV.getAddress();
1580    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1581    return LValue::MakeAddr(EmitDynamicCast(V, DCE),
1582                            MakeQualifiers(E->getType()));
1583  }
1584
1585  case CastExpr::CK_NoOp:
1586  case CastExpr::CK_ConstructorConversion:
1587  case CastExpr::CK_UserDefinedConversion:
1588  case CastExpr::CK_AnyPointerToObjCPointerCast:
1589    return EmitLValue(E->getSubExpr());
1590
1591  case CastExpr::CK_DerivedToBase: {
1592    const RecordType *DerivedClassTy =
1593      E->getSubExpr()->getType()->getAs<RecordType>();
1594    CXXRecordDecl *DerivedClassDecl =
1595      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1596
1597    const RecordType *BaseClassTy = E->getType()->getAs<RecordType>();
1598    CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseClassTy->getDecl());
1599
1600    LValue LV = EmitLValue(E->getSubExpr());
1601
1602    // Perform the derived-to-base conversion
1603    llvm::Value *Base =
1604      GetAddressOfBaseClass(LV.getAddress(), DerivedClassDecl,
1605                            BaseClassDecl, /*NullCheckValue=*/false);
1606
1607    return LValue::MakeAddr(Base, MakeQualifiers(E->getType()));
1608  }
1609  case CastExpr::CK_ToUnion: {
1610    llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1611    EmitAnyExpr(E->getSubExpr(), Temp, false);
1612
1613    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1614  }
1615  case CastExpr::CK_BaseToDerived: {
1616    const RecordType *BaseClassTy =
1617      E->getSubExpr()->getType()->getAs<RecordType>();
1618    CXXRecordDecl *BaseClassDecl =
1619      cast<CXXRecordDecl>(BaseClassTy->getDecl());
1620
1621    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1622    CXXRecordDecl *DerivedClassDecl =
1623      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1624
1625    LValue LV = EmitLValue(E->getSubExpr());
1626
1627    // Perform the base-to-derived conversion
1628    llvm::Value *Derived =
1629      GetAddressOfDerivedClass(LV.getAddress(), BaseClassDecl,
1630                               DerivedClassDecl, /*NullCheckValue=*/false);
1631
1632    return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
1633  }
1634  case CastExpr::CK_BitCast: {
1635    // This must be a reinterpret_cast (or c-style equivalent).
1636    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1637
1638    LValue LV = EmitLValue(E->getSubExpr());
1639    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1640                                           ConvertType(CE->getTypeAsWritten()));
1641    return LValue::MakeAddr(V, MakeQualifiers(E->getType()));
1642  }
1643  }
1644}
1645
1646LValue CodeGenFunction::EmitNullInitializationLValue(
1647                                              const CXXZeroInitValueExpr *E) {
1648  QualType Ty = E->getType();
1649  const llvm::Type *LTy = ConvertTypeForMem(Ty);
1650  llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
1651  CharUnits Align = getContext().getTypeAlignInChars(Ty);
1652  Alloc->setAlignment(Align.getQuantity());
1653  LValue lvalue = LValue::MakeAddr(Alloc, Qualifiers());
1654  EmitMemSetToZero(lvalue.getAddress(), Ty);
1655  return lvalue;
1656}
1657
1658//===--------------------------------------------------------------------===//
1659//                             Expression Emission
1660//===--------------------------------------------------------------------===//
1661
1662
1663RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1664                                     ReturnValueSlot ReturnValue) {
1665  // Builtins never have block type.
1666  if (E->getCallee()->getType()->isBlockPointerType())
1667    return EmitBlockCallExpr(E, ReturnValue);
1668
1669  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1670    return EmitCXXMemberCallExpr(CE, ReturnValue);
1671
1672  const Decl *TargetDecl = 0;
1673  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1674    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1675      TargetDecl = DRE->getDecl();
1676      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1677        if (unsigned builtinID = FD->getBuiltinID())
1678          return EmitBuiltinExpr(FD, builtinID, E);
1679    }
1680  }
1681
1682  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1683    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1684      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1685
1686  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1687    // C++ [expr.pseudo]p1:
1688    //   The result shall only be used as the operand for the function call
1689    //   operator (), and the result of such a call has type void. The only
1690    //   effect is the evaluation of the postfix-expression before the dot or
1691    //   arrow.
1692    EmitScalarExpr(E->getCallee());
1693    return RValue::get(0);
1694  }
1695
1696  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1697  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1698                  E->arg_begin(), E->arg_end(), TargetDecl);
1699}
1700
1701LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1702  // Comma expressions just emit their LHS then their RHS as an l-value.
1703  if (E->getOpcode() == BinaryOperator::Comma) {
1704    EmitAnyExpr(E->getLHS());
1705    EnsureInsertPoint();
1706    return EmitLValue(E->getRHS());
1707  }
1708
1709  if (E->getOpcode() == BinaryOperator::PtrMemD ||
1710      E->getOpcode() == BinaryOperator::PtrMemI)
1711    return EmitPointerToDataMemberBinaryExpr(E);
1712
1713  // Can only get l-value for binary operator expressions which are a
1714  // simple assignment of aggregate type.
1715  if (E->getOpcode() != BinaryOperator::Assign)
1716    return EmitUnsupportedLValue(E, "binary l-value expression");
1717
1718  if (!hasAggregateLLVMType(E->getType())) {
1719    // Emit the LHS as an l-value.
1720    LValue LV = EmitLValue(E->getLHS());
1721
1722    llvm::Value *RHS = EmitScalarExpr(E->getRHS());
1723    EmitStoreOfScalar(RHS, LV.getAddress(), LV.isVolatileQualified(),
1724                      E->getType());
1725    return LV;
1726  }
1727
1728  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1729  EmitAggExpr(E, Temp, false);
1730  // FIXME: Are these qualifiers correct?
1731  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1732}
1733
1734LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1735  RValue RV = EmitCallExpr(E);
1736
1737  if (!RV.isScalar())
1738    return LValue::MakeAddr(RV.getAggregateAddr(),MakeQualifiers(E->getType()));
1739
1740  assert(E->getCallReturnType()->isReferenceType() &&
1741         "Can't have a scalar return unless the return type is a "
1742         "reference type!");
1743
1744  return LValue::MakeAddr(RV.getScalarVal(), MakeQualifiers(E->getType()));
1745}
1746
1747LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1748  // FIXME: This shouldn't require another copy.
1749  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1750  EmitAggExpr(E, Temp, false);
1751  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1752}
1753
1754LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1755  llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()), "tmp");
1756  EmitCXXConstructExpr(Temp, E);
1757  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1758}
1759
1760LValue
1761CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1762  llvm::Value *Temp = EmitCXXTypeidExpr(E);
1763  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1764}
1765
1766LValue
1767CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1768  LValue LV = EmitLValue(E->getSubExpr());
1769  PushCXXTemporary(E->getTemporary(), LV.getAddress());
1770  return LV;
1771}
1772
1773LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1774  // Can only get l-value for message expression returning aggregate type
1775  RValue RV = EmitObjCMessageExpr(E);
1776  // FIXME: can this be volatile?
1777  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1778}
1779
1780llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1781                                             const ObjCIvarDecl *Ivar) {
1782  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1783}
1784
1785LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1786                                          llvm::Value *BaseValue,
1787                                          const ObjCIvarDecl *Ivar,
1788                                          unsigned CVRQualifiers) {
1789  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1790                                                   Ivar, CVRQualifiers);
1791}
1792
1793LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1794  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1795  llvm::Value *BaseValue = 0;
1796  const Expr *BaseExpr = E->getBase();
1797  Qualifiers BaseQuals;
1798  QualType ObjectTy;
1799  if (E->isArrow()) {
1800    BaseValue = EmitScalarExpr(BaseExpr);
1801    ObjectTy = BaseExpr->getType()->getPointeeType();
1802    BaseQuals = ObjectTy.getQualifiers();
1803  } else {
1804    LValue BaseLV = EmitLValue(BaseExpr);
1805    // FIXME: this isn't right for bitfields.
1806    BaseValue = BaseLV.getAddress();
1807    ObjectTy = BaseExpr->getType();
1808    BaseQuals = ObjectTy.getQualifiers();
1809  }
1810
1811  LValue LV =
1812    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1813                      BaseQuals.getCVRQualifiers());
1814  setObjCGCLValueClass(getContext(), E, LV);
1815  return LV;
1816}
1817
1818LValue
1819CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1820  // This is a special l-value that just issues sends when we load or store
1821  // through it.
1822  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1823}
1824
1825LValue CodeGenFunction::EmitObjCKVCRefLValue(
1826                                const ObjCImplicitSetterGetterRefExpr *E) {
1827  // This is a special l-value that just issues sends when we load or store
1828  // through it.
1829  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1830}
1831
1832LValue CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1833  return EmitUnsupportedLValue(E, "use of super");
1834}
1835
1836LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1837  // Can only get l-value for message expression returning aggregate type
1838  RValue RV = EmitAnyExprToTemp(E);
1839  // FIXME: can this be volatile?
1840  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1841}
1842
1843
1844LValue CodeGenFunction::EmitPointerToDataMemberLValue(const FieldDecl *Field) {
1845  const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(Field->getDeclContext());
1846  QualType NNSpecTy =
1847    getContext().getCanonicalType(
1848      getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(ClassDecl)));
1849  NNSpecTy = getContext().getPointerType(NNSpecTy);
1850  llvm::Value *V = llvm::Constant::getNullValue(ConvertType(NNSpecTy));
1851  LValue MemExpLV = EmitLValueForField(V, Field, /*isUnion=*/false,
1852                                       /*Qualifiers=*/0);
1853  const llvm::Type *ResultType = ConvertType(getContext().getPointerDiffType());
1854  V = Builder.CreatePtrToInt(MemExpLV.getAddress(), ResultType, "datamember");
1855  return LValue::MakeAddr(V, MakeQualifiers(Field->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  QualType FnType = cast<PointerType>(CalleeType)->getPointeeType();
1871  QualType ResultType = cast<FunctionType>(FnType)->getResultType();
1872
1873  CallArgList Args;
1874  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
1875
1876  // FIXME: We should not need to do this, it should be part of the function
1877  // type.
1878  unsigned CallingConvention = 0;
1879  if (const llvm::Function *F =
1880      dyn_cast<llvm::Function>(Callee->stripPointerCasts()))
1881    CallingConvention = F->getCallingConv();
1882  return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args,
1883                                                 CallingConvention),
1884                  Callee, ReturnValue, Args, TargetDecl);
1885}
1886
1887LValue CodeGenFunction::
1888EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
1889  llvm::Value *BaseV;
1890  if (E->getOpcode() == BinaryOperator::PtrMemI)
1891    BaseV = EmitScalarExpr(E->getLHS());
1892  else
1893    BaseV = EmitLValue(E->getLHS()).getAddress();
1894  const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(getLLVMContext());
1895  BaseV = Builder.CreateBitCast(BaseV, i8Ty);
1896  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
1897  llvm::Value *AddV = Builder.CreateInBoundsGEP(BaseV, OffsetV, "add.ptr");
1898
1899  QualType Ty = E->getRHS()->getType();
1900  Ty = Ty->getAs<MemberPointerType>()->getPointeeType();
1901
1902  const llvm::Type *PType = ConvertType(getContext().getPointerType(Ty));
1903  AddV = Builder.CreateBitCast(AddV, PType);
1904  return LValue::MakeAddr(AddV, MakeQualifiers(Ty));
1905}
1906
1907