CGExpr.cpp revision 06a2970e9480c6d02b367b2f970baff29b9f9721 
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::CXXBindReferenceExprClass:
460    return EmitLValue(cast<CXXBindReferenceExpr>(E)->getSubExpr());
461  case Expr::CXXExprWithTemporariesClass:
462    return EmitCXXExprWithTemporariesLValue(cast<CXXExprWithTemporaries>(E));
463  case Expr::CXXZeroInitValueExprClass:
464    return EmitNullInitializationLValue(cast<CXXZeroInitValueExpr>(E));
465  case Expr::CXXDefaultArgExprClass:
466    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
467  case Expr::CXXTypeidExprClass:
468    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
469
470  case Expr::ObjCMessageExprClass:
471    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
472  case Expr::ObjCIvarRefExprClass:
473    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
474  case Expr::ObjCPropertyRefExprClass:
475    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
476  case Expr::ObjCImplicitSetterGetterRefExprClass:
477    return EmitObjCKVCRefLValue(cast<ObjCImplicitSetterGetterRefExpr>(E));
478  case Expr::ObjCSuperExprClass:
479    return EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
480
481  case Expr::StmtExprClass:
482    return EmitStmtExprLValue(cast<StmtExpr>(E));
483  case Expr::UnaryOperatorClass:
484    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
485  case Expr::ArraySubscriptExprClass:
486    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
487  case Expr::ExtVectorElementExprClass:
488    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
489  case Expr::MemberExprClass:
490    return EmitMemberExpr(cast<MemberExpr>(E));
491  case Expr::CompoundLiteralExprClass:
492    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
493  case Expr::ConditionalOperatorClass:
494    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
495  case Expr::ChooseExprClass:
496    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
497  case Expr::ImplicitCastExprClass:
498  case Expr::CStyleCastExprClass:
499  case Expr::CXXFunctionalCastExprClass:
500  case Expr::CXXStaticCastExprClass:
501  case Expr::CXXDynamicCastExprClass:
502  case Expr::CXXReinterpretCastExprClass:
503  case Expr::CXXConstCastExprClass:
504    return EmitCastLValue(cast<CastExpr>(E));
505  }
506}
507
508llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
509                                               QualType Ty) {
510  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
511  if (Volatile)
512    Load->setVolatile(true);
513
514  // Bool can have different representation in memory than in registers.
515  llvm::Value *V = Load;
516  if (Ty->isBooleanType())
517    if (V->getType() != llvm::Type::getInt1Ty(VMContext))
518      V = Builder.CreateTrunc(V, llvm::Type::getInt1Ty(VMContext), "tobool");
519
520  return V;
521}
522
523void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
524                                        bool Volatile, QualType Ty) {
525
526  if (Ty->isBooleanType()) {
527    // Bool can have different representation in memory than in registers.
528    const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
529    Value = Builder.CreateIntCast(Value, DstPtr->getElementType(), false);
530  }
531  Builder.CreateStore(Value, Addr, Volatile);
532}
533
534/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
535/// method emits the address of the lvalue, then loads the result as an rvalue,
536/// returning the rvalue.
537RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
538  if (LV.isObjCWeak()) {
539    // load of a __weak object.
540    llvm::Value *AddrWeakObj = LV.getAddress();
541    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
542                                                             AddrWeakObj));
543  }
544
545  if (LV.isSimple()) {
546    llvm::Value *Ptr = LV.getAddress();
547    const llvm::Type *EltTy =
548      cast<llvm::PointerType>(Ptr->getType())->getElementType();
549
550    // Simple scalar l-value.
551    if (EltTy->isSingleValueType())
552      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
553                                          ExprType));
554
555    assert(ExprType->isFunctionType() && "Unknown scalar value");
556    return RValue::get(Ptr);
557  }
558
559  if (LV.isVectorElt()) {
560    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
561                                          LV.isVolatileQualified(), "tmp");
562    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
563                                                    "vecext"));
564  }
565
566  // If this is a reference to a subset of the elements of a vector, either
567  // shuffle the input or extract/insert them as appropriate.
568  if (LV.isExtVectorElt())
569    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
570
571  if (LV.isBitfield())
572    return EmitLoadOfBitfieldLValue(LV, ExprType);
573
574  if (LV.isPropertyRef())
575    return EmitLoadOfPropertyRefLValue(LV, ExprType);
576
577  assert(LV.isKVCRef() && "Unknown LValue type!");
578  return EmitLoadOfKVCRefLValue(LV, ExprType);
579}
580
581RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
582                                                 QualType ExprType) {
583  unsigned StartBit = LV.getBitfieldStartBit();
584  unsigned BitfieldSize = LV.getBitfieldSize();
585  llvm::Value *Ptr = LV.getBitfieldAddr();
586
587  const llvm::Type *EltTy =
588    cast<llvm::PointerType>(Ptr->getType())->getElementType();
589  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
590
591  // In some cases the bitfield may straddle two memory locations.  Currently we
592  // load the entire bitfield, then do the magic to sign-extend it if
593  // necessary. This results in somewhat more code than necessary for the common
594  // case (one load), since two shifts accomplish both the masking and sign
595  // extension.
596  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
597  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
598
599  // Shift to proper location.
600  if (StartBit)
601    Val = Builder.CreateLShr(Val, StartBit, "bf.lo");
602
603  // Mask off unused bits.
604  llvm::Constant *LowMask = llvm::ConstantInt::get(VMContext,
605                                llvm::APInt::getLowBitsSet(EltTySize, LowBits));
606  Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
607
608  // Fetch the high bits if necessary.
609  if (LowBits < BitfieldSize) {
610    unsigned HighBits = BitfieldSize - LowBits;
611    llvm::Value *HighPtr = Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
612                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
613    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
614                                              LV.isVolatileQualified(),
615                                              "tmp");
616
617    // Mask off unused bits.
618    llvm::Constant *HighMask = llvm::ConstantInt::get(VMContext,
619                               llvm::APInt::getLowBitsSet(EltTySize, HighBits));
620    HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
621
622    // Shift to proper location and or in to bitfield value.
623    HighVal = Builder.CreateShl(HighVal, LowBits);
624    Val = Builder.CreateOr(Val, HighVal, "bf.val");
625  }
626
627  // Sign extend if necessary.
628  if (LV.isBitfieldSigned()) {
629    llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
630                                                    EltTySize - BitfieldSize);
631    Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
632                             ExtraBits, "bf.val.sext");
633  }
634
635  // The bitfield type and the normal type differ when the storage sizes differ
636  // (currently just _Bool).
637  Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
638
639  return RValue::get(Val);
640}
641
642RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
643                                                    QualType ExprType) {
644  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
645}
646
647RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
648                                               QualType ExprType) {
649  return EmitObjCPropertyGet(LV.getKVCRefExpr());
650}
651
652// If this is a reference to a subset of the elements of a vector, create an
653// appropriate shufflevector.
654RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
655                                                         QualType ExprType) {
656  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
657                                        LV.isVolatileQualified(), "tmp");
658
659  const llvm::Constant *Elts = LV.getExtVectorElts();
660
661  // If the result of the expression is a non-vector type, we must be extracting
662  // a single element.  Just codegen as an extractelement.
663  const VectorType *ExprVT = ExprType->getAs<VectorType>();
664  if (!ExprVT) {
665    unsigned InIdx = getAccessedFieldNo(0, Elts);
666    llvm::Value *Elt = llvm::ConstantInt::get(
667                                      llvm::Type::getInt32Ty(VMContext), InIdx);
668    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
669  }
670
671  // Always use shuffle vector to try to retain the original program structure
672  unsigned NumResultElts = ExprVT->getNumElements();
673
674  llvm::SmallVector<llvm::Constant*, 4> Mask;
675  for (unsigned i = 0; i != NumResultElts; ++i) {
676    unsigned InIdx = getAccessedFieldNo(i, Elts);
677    Mask.push_back(llvm::ConstantInt::get(
678                                     llvm::Type::getInt32Ty(VMContext), InIdx));
679  }
680
681  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
682  Vec = Builder.CreateShuffleVector(Vec,
683                                    llvm::UndefValue::get(Vec->getType()),
684                                    MaskV, "tmp");
685  return RValue::get(Vec);
686}
687
688
689
690/// EmitStoreThroughLValue - Store the specified rvalue into the specified
691/// lvalue, where both are guaranteed to the have the same type, and that type
692/// is 'Ty'.
693void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
694                                             QualType Ty) {
695  if (!Dst.isSimple()) {
696    if (Dst.isVectorElt()) {
697      // Read/modify/write the vector, inserting the new element.
698      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
699                                            Dst.isVolatileQualified(), "tmp");
700      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
701                                        Dst.getVectorIdx(), "vecins");
702      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
703      return;
704    }
705
706    // If this is an update of extended vector elements, insert them as
707    // appropriate.
708    if (Dst.isExtVectorElt())
709      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
710
711    if (Dst.isBitfield())
712      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
713
714    if (Dst.isPropertyRef())
715      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
716
717    assert(Dst.isKVCRef() && "Unknown LValue type");
718    return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
719  }
720
721  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
722    // load of a __weak object.
723    llvm::Value *LvalueDst = Dst.getAddress();
724    llvm::Value *src = Src.getScalarVal();
725     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
726    return;
727  }
728
729  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
730    // load of a __strong object.
731    llvm::Value *LvalueDst = Dst.getAddress();
732    llvm::Value *src = Src.getScalarVal();
733    if (Dst.isObjCIvar()) {
734      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
735      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
736      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
737      llvm::Value *dst = RHS;
738      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
739      llvm::Value *LHS =
740        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
741      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
742      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
743                                              BytesBetween);
744    } else if (Dst.isGlobalObjCRef())
745      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
746    else
747      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
748    return;
749  }
750
751  assert(Src.isScalar() && "Can't emit an agg store with this method");
752  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
753                    Dst.isVolatileQualified(), Ty);
754}
755
756void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
757                                                     QualType Ty,
758                                                     llvm::Value **Result) {
759  unsigned StartBit = Dst.getBitfieldStartBit();
760  unsigned BitfieldSize = Dst.getBitfieldSize();
761  llvm::Value *Ptr = Dst.getBitfieldAddr();
762
763  const llvm::Type *EltTy =
764    cast<llvm::PointerType>(Ptr->getType())->getElementType();
765  unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
766
767  // Get the new value, cast to the appropriate type and masked to exactly the
768  // size of the bit-field.
769  llvm::Value *SrcVal = Src.getScalarVal();
770  llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp");
771  llvm::Constant *Mask = llvm::ConstantInt::get(VMContext,
772                           llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
773  NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
774
775  // Return the new value of the bit-field, if requested.
776  if (Result) {
777    // Cast back to the proper type for result.
778    const llvm::Type *SrcTy = SrcVal->getType();
779    llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false,
780                                                  "bf.reload.val");
781
782    // Sign extend if necessary.
783    if (Dst.isBitfieldSigned()) {
784      unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy);
785      llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy,
786                                                      SrcTySize - BitfieldSize);
787      SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits),
788                                    ExtraBits, "bf.reload.sext");
789    }
790
791    *Result = SrcTrunc;
792  }
793
794  // In some cases the bitfield may straddle two memory locations.  Emit the low
795  // part first and check to see if the high needs to be done.
796  unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
797  llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
798                                           "bf.prev.low");
799
800  // Compute the mask for zero-ing the low part of this bitfield.
801  llvm::Constant *InvMask =
802    llvm::ConstantInt::get(VMContext,
803             ~llvm::APInt::getBitsSet(EltTySize, StartBit, StartBit + LowBits));
804
805  // Compute the new low part as
806  //   LowVal = (LowVal & InvMask) | (NewVal << StartBit),
807  // with the shift of NewVal implicitly stripping the high bits.
808  llvm::Value *NewLowVal =
809    Builder.CreateShl(NewVal, StartBit, "bf.value.lo");
810  LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
811  LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
812
813  // Write back.
814  Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
815
816  // If the low part doesn't cover the bitfield emit a high part.
817  if (LowBits < BitfieldSize) {
818    unsigned HighBits = BitfieldSize - LowBits;
819    llvm::Value *HighPtr =  Builder.CreateGEP(Ptr, llvm::ConstantInt::get(
820                            llvm::Type::getInt32Ty(VMContext), 1), "bf.ptr.hi");
821    llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
822                                              Dst.isVolatileQualified(),
823                                              "bf.prev.hi");
824
825    // Compute the mask for zero-ing the high part of this bitfield.
826    llvm::Constant *InvMask =
827      llvm::ConstantInt::get(VMContext, ~llvm::APInt::getLowBitsSet(EltTySize,
828                               HighBits));
829
830    // Compute the new high part as
831    //   HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
832    // where the high bits of NewVal have already been cleared and the
833    // shift stripping the low bits.
834    llvm::Value *NewHighVal =
835      Builder.CreateLShr(NewVal, LowBits, "bf.value.high");
836    HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
837    HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
838
839    // Write back.
840    Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
841  }
842}
843
844void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
845                                                        LValue Dst,
846                                                        QualType Ty) {
847  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
848}
849
850void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
851                                                   LValue Dst,
852                                                   QualType Ty) {
853  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
854}
855
856void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
857                                                               LValue Dst,
858                                                               QualType Ty) {
859  // This access turns into a read/modify/write of the vector.  Load the input
860  // value now.
861  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
862                                        Dst.isVolatileQualified(), "tmp");
863  const llvm::Constant *Elts = Dst.getExtVectorElts();
864
865  llvm::Value *SrcVal = Src.getScalarVal();
866
867  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
868    unsigned NumSrcElts = VTy->getNumElements();
869    unsigned NumDstElts =
870       cast<llvm::VectorType>(Vec->getType())->getNumElements();
871    if (NumDstElts == NumSrcElts) {
872      // Use shuffle vector is the src and destination are the same number of
873      // elements and restore the vector mask since it is on the side it will be
874      // stored.
875      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
876      for (unsigned i = 0; i != NumSrcElts; ++i) {
877        unsigned InIdx = getAccessedFieldNo(i, Elts);
878        Mask[InIdx] = llvm::ConstantInt::get(
879                                          llvm::Type::getInt32Ty(VMContext), i);
880      }
881
882      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
883      Vec = Builder.CreateShuffleVector(SrcVal,
884                                        llvm::UndefValue::get(Vec->getType()),
885                                        MaskV, "tmp");
886    } else if (NumDstElts > NumSrcElts) {
887      // Extended the source vector to the same length and then shuffle it
888      // into the destination.
889      // FIXME: since we're shuffling with undef, can we just use the indices
890      //        into that?  This could be simpler.
891      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
892      const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
893      unsigned i;
894      for (i = 0; i != NumSrcElts; ++i)
895        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
896      for (; i != NumDstElts; ++i)
897        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
898      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
899                                                        ExtMask.size());
900      llvm::Value *ExtSrcVal =
901        Builder.CreateShuffleVector(SrcVal,
902                                    llvm::UndefValue::get(SrcVal->getType()),
903                                    ExtMaskV, "tmp");
904      // build identity
905      llvm::SmallVector<llvm::Constant*, 4> Mask;
906      for (unsigned i = 0; i != NumDstElts; ++i)
907        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
908
909      // modify when what gets shuffled in
910      for (unsigned i = 0; i != NumSrcElts; ++i) {
911        unsigned Idx = getAccessedFieldNo(i, Elts);
912        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
913      }
914      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
915      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
916    } else {
917      // We should never shorten the vector
918      assert(0 && "unexpected shorten vector length");
919    }
920  } else {
921    // If the Src is a scalar (not a vector) it must be updating one element.
922    unsigned InIdx = getAccessedFieldNo(0, Elts);
923    const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
924    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
925    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
926  }
927
928  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
929}
930
931// setObjCGCLValueClass - sets class of he lvalue for the purpose of
932// generating write-barries API. It is currently a global, ivar,
933// or neither.
934static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
935                                 LValue &LV) {
936  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
937    return;
938
939  if (isa<ObjCIvarRefExpr>(E)) {
940    LV.SetObjCIvar(LV, true);
941    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
942    LV.setBaseIvarExp(Exp->getBase());
943    LV.SetObjCArray(LV, E->getType()->isArrayType());
944    return;
945  }
946
947  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
948    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
949      if ((VD->isBlockVarDecl() && !VD->hasLocalStorage()) ||
950          VD->isFileVarDecl())
951        LV.SetGlobalObjCRef(LV, true);
952    }
953    LV.SetObjCArray(LV, E->getType()->isArrayType());
954    return;
955  }
956
957  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
958    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
959    return;
960  }
961
962  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
963    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
964    if (LV.isObjCIvar()) {
965      // If cast is to a structure pointer, follow gcc's behavior and make it
966      // a non-ivar write-barrier.
967      QualType ExpTy = E->getType();
968      if (ExpTy->isPointerType())
969        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
970      if (ExpTy->isRecordType())
971        LV.SetObjCIvar(LV, false);
972    }
973    return;
974  }
975  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
976    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
977    return;
978  }
979
980  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
981    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
982    return;
983  }
984
985  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
986    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
987    if (LV.isObjCIvar() && !LV.isObjCArray())
988      // Using array syntax to assigning to what an ivar points to is not
989      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
990      LV.SetObjCIvar(LV, false);
991    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
992      // Using array syntax to assigning to what global points to is not
993      // same as assigning to the global itself. {id *G;} G[i] = 0;
994      LV.SetGlobalObjCRef(LV, false);
995    return;
996  }
997
998  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
999    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1000    // We don't know if member is an 'ivar', but this flag is looked at
1001    // only in the context of LV.isObjCIvar().
1002    LV.SetObjCArray(LV, E->getType()->isArrayType());
1003    return;
1004  }
1005}
1006
1007static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1008                                      const Expr *E, const VarDecl *VD) {
1009  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1010         "Var decl must have external storage or be a file var decl!");
1011
1012  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1013  if (VD->getType()->isReferenceType())
1014    V = CGF.Builder.CreateLoad(V, "tmp");
1015  LValue LV = LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1016  setObjCGCLValueClass(CGF.getContext(), E, LV);
1017  return LV;
1018}
1019
1020static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1021                                      const Expr *E, const FunctionDecl *FD) {
1022  llvm::Value* V = CGF.CGM.GetAddrOfFunction(FD);
1023  if (!FD->hasPrototype()) {
1024    if (const FunctionProtoType *Proto =
1025            FD->getType()->getAs<FunctionProtoType>()) {
1026      // Ugly case: for a K&R-style definition, the type of the definition
1027      // isn't the same as the type of a use.  Correct for this with a
1028      // bitcast.
1029      QualType NoProtoType =
1030          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1031      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1032      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1033    }
1034  }
1035  return LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1036}
1037
1038LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1039  const NamedDecl *ND = E->getDecl();
1040
1041  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1042
1043    // Check if this is a global variable.
1044    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1045      return EmitGlobalVarDeclLValue(*this, E, VD);
1046
1047    bool NonGCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
1048
1049    llvm::Value *V = LocalDeclMap[VD];
1050    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1051
1052    Qualifiers Quals = MakeQualifiers(E->getType());
1053    // local variables do not get their gc attribute set.
1054    // local static?
1055    if (NonGCable) Quals.removeObjCGCAttr();
1056
1057    if (VD->hasAttr<BlocksAttr>()) {
1058      V = Builder.CreateStructGEP(V, 1, "forwarding");
1059      V = Builder.CreateLoad(V);
1060      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
1061                                  VD->getNameAsString());
1062    }
1063    if (VD->getType()->isReferenceType())
1064      V = Builder.CreateLoad(V, "tmp");
1065    LValue LV = LValue::MakeAddr(V, Quals);
1066    LValue::SetObjCNonGC(LV, NonGCable);
1067    setObjCGCLValueClass(getContext(), E, LV);
1068    return LV;
1069  }
1070
1071  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1072    return EmitFunctionDeclLValue(*this, E, FD);
1073
1074  if (E->getQualifier()) {
1075    // FIXME: the qualifier check does not seem sufficient here
1076    return EmitPointerToDataMemberLValue(cast<FieldDecl>(ND));
1077  }
1078
1079  assert(false && "Unhandled DeclRefExpr");
1080
1081  // an invalid LValue, but the assert will
1082  // ensure that this point is never reached.
1083  return LValue();
1084}
1085
1086LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1087  return LValue::MakeAddr(GetAddrOfBlockDecl(E), MakeQualifiers(E->getType()));
1088}
1089
1090LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1091  // __extension__ doesn't affect lvalue-ness.
1092  if (E->getOpcode() == UnaryOperator::Extension)
1093    return EmitLValue(E->getSubExpr());
1094
1095  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1096  switch (E->getOpcode()) {
1097  default: assert(0 && "Unknown unary operator lvalue!");
1098  case UnaryOperator::Deref: {
1099    QualType T = E->getSubExpr()->getType()->getPointeeType();
1100    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1101
1102    Qualifiers Quals = MakeQualifiers(T);
1103    Quals.setAddressSpace(ExprTy.getAddressSpace());
1104
1105    LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()), Quals);
1106    // We should not generate __weak write barrier on indirect reference
1107    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1108    // But, we continue to generate __strong write barrier on indirect write
1109    // into a pointer to object.
1110    if (getContext().getLangOptions().ObjC1 &&
1111        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1112        LV.isObjCWeak())
1113      LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1114    return LV;
1115  }
1116  case UnaryOperator::Real:
1117  case UnaryOperator::Imag: {
1118    LValue LV = EmitLValue(E->getSubExpr());
1119    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
1120    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
1121                                                    Idx, "idx"),
1122                            MakeQualifiers(ExprTy));
1123  }
1124  case UnaryOperator::PreInc:
1125  case UnaryOperator::PreDec: {
1126    LValue LV = EmitLValue(E->getSubExpr());
1127    bool isInc = E->getOpcode() == UnaryOperator::PreInc;
1128
1129    if (E->getType()->isAnyComplexType())
1130      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1131    else
1132      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1133    return LV;
1134  }
1135  }
1136}
1137
1138LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1139  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E),
1140                          Qualifiers());
1141}
1142
1143LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1144  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1145                          Qualifiers());
1146}
1147
1148
1149LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
1150  std::string GlobalVarName;
1151
1152  switch (Type) {
1153  default: assert(0 && "Invalid type");
1154  case PredefinedExpr::Func:
1155    GlobalVarName = "__func__.";
1156    break;
1157  case PredefinedExpr::Function:
1158    GlobalVarName = "__FUNCTION__.";
1159    break;
1160  case PredefinedExpr::PrettyFunction:
1161    GlobalVarName = "__PRETTY_FUNCTION__.";
1162    break;
1163  }
1164
1165  llvm::StringRef FnName = CurFn->getName();
1166  if (FnName.startswith("\01"))
1167    FnName = FnName.substr(1);
1168  GlobalVarName += FnName;
1169
1170  std::string FunctionName =
1171    PredefinedExpr::ComputeName(getContext(), (PredefinedExpr::IdentType)Type,
1172                                CurCodeDecl);
1173
1174  llvm::Constant *C =
1175    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1176  return LValue::MakeAddr(C, Qualifiers());
1177}
1178
1179LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1180  switch (E->getIdentType()) {
1181  default:
1182    return EmitUnsupportedLValue(E, "predefined expression");
1183  case PredefinedExpr::Func:
1184  case PredefinedExpr::Function:
1185  case PredefinedExpr::PrettyFunction:
1186    return EmitPredefinedFunctionName(E->getIdentType());
1187  }
1188}
1189
1190llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1191  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1192
1193  // If we are not optimzing, don't collapse all calls to trap in the function
1194  // to the same call, that way, in the debugger they can see which operation
1195  // did in fact fail.  If we are optimizing, we collpase all call to trap down
1196  // to just one per function to save on codesize.
1197  if (GCO.OptimizationLevel
1198      && TrapBB)
1199    return TrapBB;
1200
1201  llvm::BasicBlock *Cont = 0;
1202  if (HaveInsertPoint()) {
1203    Cont = createBasicBlock("cont");
1204    EmitBranch(Cont);
1205  }
1206  TrapBB = createBasicBlock("trap");
1207  EmitBlock(TrapBB);
1208
1209  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1210  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1211  TrapCall->setDoesNotReturn();
1212  TrapCall->setDoesNotThrow();
1213  Builder.CreateUnreachable();
1214
1215  if (Cont)
1216    EmitBlock(Cont);
1217  return TrapBB;
1218}
1219
1220LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1221  // The index must always be an integer, which is not an aggregate.  Emit it.
1222  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1223  QualType IdxTy  = E->getIdx()->getType();
1224  bool IdxSigned = IdxTy->isSignedIntegerType();
1225
1226  // If the base is a vector type, then we are forming a vector element lvalue
1227  // with this subscript.
1228  if (E->getBase()->getType()->isVectorType()) {
1229    // Emit the vector as an lvalue to get its address.
1230    LValue LHS = EmitLValue(E->getBase());
1231    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1232    Idx = Builder.CreateIntCast(Idx,
1233                          llvm::Type::getInt32Ty(VMContext), IdxSigned, "vidx");
1234    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1235                                 E->getBase()->getType().getCVRQualifiers());
1236  }
1237
1238  // The base must be a pointer, which is not an aggregate.  Emit it.
1239  llvm::Value *Base = EmitScalarExpr(E->getBase());
1240
1241  // Extend or truncate the index type to 32 or 64-bits.
1242  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1243  if (IdxBitwidth != LLVMPointerWidth)
1244    Idx = Builder.CreateIntCast(Idx,
1245                            llvm::IntegerType::get(VMContext, LLVMPointerWidth),
1246                                IdxSigned, "idxprom");
1247
1248  // FIXME: As llvm implements the object size checking, this can come out.
1249  if (CatchUndefined) {
1250    if (const ImplicitCastExpr *ICE=dyn_cast<ImplicitCastExpr>(E->getBase())) {
1251      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1252        if (ICE->getCastKind() == CastExpr::CK_ArrayToPointerDecay) {
1253          if (const ConstantArrayType *CAT
1254              = getContext().getAsConstantArrayType(DRE->getType())) {
1255            llvm::APInt Size = CAT->getSize();
1256            llvm::BasicBlock *Cont = createBasicBlock("cont");
1257            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1258                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1259                                 Cont, getTrapBB());
1260            EmitBlock(Cont);
1261          }
1262        }
1263      }
1264    }
1265  }
1266
1267  // We know that the pointer points to a type of the correct size, unless the
1268  // size is a VLA or Objective-C interface.
1269  llvm::Value *Address = 0;
1270  if (const VariableArrayType *VAT =
1271        getContext().getAsVariableArrayType(E->getType())) {
1272    llvm::Value *VLASize = GetVLASize(VAT);
1273
1274    Idx = Builder.CreateMul(Idx, VLASize);
1275
1276    QualType BaseType = getContext().getBaseElementType(VAT);
1277
1278    CharUnits BaseTypeSize = getContext().getTypeSizeInChars(BaseType);
1279    Idx = Builder.CreateUDiv(Idx,
1280                             llvm::ConstantInt::get(Idx->getType(),
1281                                 BaseTypeSize.getQuantity()));
1282    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1283  } else if (const ObjCInterfaceType *OIT =
1284             dyn_cast<ObjCInterfaceType>(E->getType())) {
1285    llvm::Value *InterfaceSize =
1286      llvm::ConstantInt::get(Idx->getType(),
1287          getContext().getTypeSizeInChars(OIT).getQuantity());
1288
1289    Idx = Builder.CreateMul(Idx, InterfaceSize);
1290
1291    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1292    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1293                                Idx, "arrayidx");
1294    Address = Builder.CreateBitCast(Address, Base->getType());
1295  } else {
1296    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1297  }
1298
1299  QualType T = E->getBase()->getType()->getPointeeType();
1300  assert(!T.isNull() &&
1301         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1302
1303  Qualifiers Quals = MakeQualifiers(T);
1304  Quals.setAddressSpace(E->getBase()->getType().getAddressSpace());
1305
1306  LValue LV = LValue::MakeAddr(Address, Quals);
1307  if (getContext().getLangOptions().ObjC1 &&
1308      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1309    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1310    setObjCGCLValueClass(getContext(), E, LV);
1311  }
1312  return LV;
1313}
1314
1315static
1316llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1317                                       llvm::SmallVector<unsigned, 4> &Elts) {
1318  llvm::SmallVector<llvm::Constant*, 4> CElts;
1319
1320  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1321    CElts.push_back(llvm::ConstantInt::get(
1322                                   llvm::Type::getInt32Ty(VMContext), Elts[i]));
1323
1324  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1325}
1326
1327LValue CodeGenFunction::
1328EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1329  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1330
1331  // Emit the base vector as an l-value.
1332  LValue Base;
1333
1334  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1335  if (E->isArrow()) {
1336    // If it is a pointer to a vector, emit the address and form an lvalue with
1337    // it.
1338    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1339    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1340    Qualifiers Quals = MakeQualifiers(PT->getPointeeType());
1341    Quals.removeObjCGCAttr();
1342    Base = LValue::MakeAddr(Ptr, Quals);
1343  } else if (E->getBase()->isLvalue(getContext()) == Expr::LV_Valid) {
1344    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1345    // emit the base as an lvalue.
1346    assert(E->getBase()->getType()->isVectorType());
1347    Base = EmitLValue(E->getBase());
1348  } else {
1349    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1350    assert(E->getBase()->getType()->getAs<VectorType>() &&
1351           "Result must be a vector");
1352    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1353
1354    // Store the vector to memory (because LValue wants an address).
1355    llvm::Value *VecMem =CreateTempAlloca(ConvertType(E->getBase()->getType()));
1356    Builder.CreateStore(Vec, VecMem);
1357    Base = LValue::MakeAddr(VecMem, Qualifiers());
1358  }
1359
1360  // Encode the element access list into a vector of unsigned indices.
1361  llvm::SmallVector<unsigned, 4> Indices;
1362  E->getEncodedElementAccess(Indices);
1363
1364  if (Base.isSimple()) {
1365    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1366    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1367                                    Base.getVRQualifiers());
1368  }
1369  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1370
1371  llvm::Constant *BaseElts = Base.getExtVectorElts();
1372  llvm::SmallVector<llvm::Constant *, 4> CElts;
1373
1374  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1375    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1376      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1377    else
1378      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1379  }
1380  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1381  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1382                                  Base.getVRQualifiers());
1383}
1384
1385LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1386  bool isNonGC = false;
1387  Expr *BaseExpr = E->getBase();
1388  llvm::Value *BaseValue = NULL;
1389  Qualifiers BaseQuals;
1390
1391  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1392  if (E->isArrow()) {
1393    BaseValue = EmitScalarExpr(BaseExpr);
1394    const PointerType *PTy =
1395      BaseExpr->getType()->getAs<PointerType>();
1396    BaseQuals = PTy->getPointeeType().getQualifiers();
1397  } else if (isa<ObjCPropertyRefExpr>(BaseExpr->IgnoreParens()) ||
1398             isa<ObjCImplicitSetterGetterRefExpr>(
1399               BaseExpr->IgnoreParens())) {
1400    RValue RV = EmitObjCPropertyGet(BaseExpr);
1401    BaseValue = RV.getAggregateAddr();
1402    BaseQuals = BaseExpr->getType().getQualifiers();
1403  } else {
1404    LValue BaseLV = EmitLValue(BaseExpr);
1405    if (BaseLV.isNonGC())
1406      isNonGC = true;
1407    // FIXME: this isn't right for bitfields.
1408    BaseValue = BaseLV.getAddress();
1409    QualType BaseTy = BaseExpr->getType();
1410    BaseQuals = BaseTy.getQualifiers();
1411  }
1412
1413  NamedDecl *ND = E->getMemberDecl();
1414  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1415    LValue LV = EmitLValueForField(BaseValue, Field,
1416                                   BaseQuals.getCVRQualifiers());
1417    LValue::SetObjCNonGC(LV, isNonGC);
1418    setObjCGCLValueClass(getContext(), E, LV);
1419    return LV;
1420  }
1421
1422  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1423    return EmitGlobalVarDeclLValue(*this, E, VD);
1424
1425  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1426    return EmitFunctionDeclLValue(*this, E, FD);
1427
1428  assert(false && "Unhandled member declaration!");
1429  return LValue();
1430}
1431
1432LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
1433                                              const FieldDecl* Field,
1434                                              unsigned CVRQualifiers) {
1435  CodeGenTypes::BitFieldInfo Info = CGM.getTypes().getBitFieldInfo(Field);
1436
1437  // FIXME: CodeGenTypes should expose a method to get the appropriate type for
1438  // FieldTy (the appropriate type is ABI-dependent).
1439  const llvm::Type *FieldTy =
1440    CGM.getTypes().ConvertTypeForMem(Field->getType());
1441  const llvm::PointerType *BaseTy =
1442  cast<llvm::PointerType>(BaseValue->getType());
1443  unsigned AS = BaseTy->getAddressSpace();
1444  BaseValue = Builder.CreateBitCast(BaseValue,
1445                                    llvm::PointerType::get(FieldTy, AS),
1446                                    "tmp");
1447
1448  llvm::Value *Idx =
1449    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), Info.FieldNo);
1450  llvm::Value *V = Builder.CreateGEP(BaseValue, Idx, "tmp");
1451
1452  return LValue::MakeBitfield(V, Info.Start, Info.Size,
1453                              Field->getType()->isSignedIntegerType(),
1454                            Field->getType().getCVRQualifiers()|CVRQualifiers);
1455}
1456
1457LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
1458                                           const FieldDecl* Field,
1459                                           unsigned CVRQualifiers) {
1460  if (Field->isBitField())
1461    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1462
1463  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
1464  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1465
1466  // Match union field type.
1467  if (Field->getParent()->isUnion()) {
1468    const llvm::Type *FieldTy =
1469      CGM.getTypes().ConvertTypeForMem(Field->getType());
1470    const llvm::PointerType * BaseTy =
1471      cast<llvm::PointerType>(BaseValue->getType());
1472    unsigned AS = BaseTy->getAddressSpace();
1473    V = Builder.CreateBitCast(V,
1474                              llvm::PointerType::get(FieldTy, AS),
1475                              "tmp");
1476  }
1477  if (Field->getType()->isReferenceType())
1478    V = Builder.CreateLoad(V, "tmp");
1479
1480  Qualifiers Quals = MakeQualifiers(Field->getType());
1481  Quals.addCVRQualifiers(CVRQualifiers);
1482  // __weak attribute on a field is ignored.
1483  if (Quals.getObjCGCAttr() == Qualifiers::Weak)
1484    Quals.removeObjCGCAttr();
1485
1486  return LValue::MakeAddr(V, Quals);
1487}
1488
1489LValue
1490CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value* BaseValue,
1491                                                  const FieldDecl* Field,
1492                                                  unsigned CVRQualifiers) {
1493  QualType FieldType = Field->getType();
1494
1495  if (!FieldType->isReferenceType())
1496    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1497
1498  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
1499  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1500
1501  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1502
1503  return LValue::MakeAddr(V, MakeQualifiers(FieldType));
1504}
1505
1506LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1507  const llvm::Type *LTy = ConvertType(E->getType());
1508  llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
1509
1510  const Expr* InitExpr = E->getInitializer();
1511  LValue Result = LValue::MakeAddr(DeclPtr, MakeQualifiers(E->getType()));
1512
1513  if (E->getType()->isComplexType())
1514    EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
1515  else if (hasAggregateLLVMType(E->getType()))
1516    EmitAnyExpr(InitExpr, DeclPtr, false);
1517  else
1518    EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
1519
1520  return Result;
1521}
1522
1523LValue
1524CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator* E) {
1525  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
1526    if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1527      Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1528      if (Live)
1529        return EmitLValue(Live);
1530    }
1531
1532    if (!E->getLHS())
1533      return EmitUnsupportedLValue(E, "conditional operator with missing LHS");
1534
1535    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1536    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1537    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1538
1539    EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1540
1541    EmitBlock(LHSBlock);
1542
1543    LValue LHS = EmitLValue(E->getLHS());
1544    if (!LHS.isSimple())
1545      return EmitUnsupportedLValue(E, "conditional operator");
1546
1547    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1548    Builder.CreateStore(LHS.getAddress(), Temp);
1549    EmitBranch(ContBlock);
1550
1551    EmitBlock(RHSBlock);
1552    LValue RHS = EmitLValue(E->getRHS());
1553    if (!RHS.isSimple())
1554      return EmitUnsupportedLValue(E, "conditional operator");
1555
1556    Builder.CreateStore(RHS.getAddress(), Temp);
1557    EmitBranch(ContBlock);
1558
1559    EmitBlock(ContBlock);
1560
1561    Temp = Builder.CreateLoad(Temp, "lv");
1562    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1563  }
1564
1565  // ?: here should be an aggregate.
1566  assert((hasAggregateLLVMType(E->getType()) &&
1567          !E->getType()->isAnyComplexType()) &&
1568         "Unexpected conditional operator!");
1569
1570  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1571  EmitAggExpr(E, Temp, false);
1572
1573  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1574}
1575
1576/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1577/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1578/// otherwise if a cast is needed by the code generator in an lvalue context,
1579/// then it must mean that we need the address of an aggregate in order to
1580/// access one of its fields.  This can happen for all the reasons that casts
1581/// are permitted with aggregate result, including noop aggregate casts, and
1582/// cast from scalar to union.
1583LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1584  switch (E->getCastKind()) {
1585  default:
1586    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1587
1588  case CastExpr::CK_Dynamic: {
1589    LValue LV = EmitLValue(E->getSubExpr());
1590    llvm::Value *V = LV.getAddress();
1591    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1592    return LValue::MakeAddr(EmitDynamicCast(V, DCE),
1593                            MakeQualifiers(E->getType()));
1594  }
1595
1596  case CastExpr::CK_NoOp:
1597  case CastExpr::CK_ConstructorConversion:
1598  case CastExpr::CK_UserDefinedConversion:
1599  case CastExpr::CK_AnyPointerToObjCPointerCast:
1600    return EmitLValue(E->getSubExpr());
1601
1602  case CastExpr::CK_DerivedToBase: {
1603    const RecordType *DerivedClassTy =
1604      E->getSubExpr()->getType()->getAs<RecordType>();
1605    CXXRecordDecl *DerivedClassDecl =
1606      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1607
1608    const RecordType *BaseClassTy = E->getType()->getAs<RecordType>();
1609    CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(BaseClassTy->getDecl());
1610
1611    LValue LV = EmitLValue(E->getSubExpr());
1612
1613    // Perform the derived-to-base conversion
1614    llvm::Value *Base =
1615      GetAddressOfBaseClass(LV.getAddress(), DerivedClassDecl,
1616                            BaseClassDecl, /*NullCheckValue=*/false);
1617
1618    return LValue::MakeAddr(Base, MakeQualifiers(E->getType()));
1619  }
1620  case CastExpr::CK_ToUnion: {
1621    llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1622    EmitAnyExpr(E->getSubExpr(), Temp, false);
1623
1624    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1625  }
1626  case CastExpr::CK_BaseToDerived: {
1627    const RecordType *BaseClassTy =
1628      E->getSubExpr()->getType()->getAs<RecordType>();
1629    CXXRecordDecl *BaseClassDecl =
1630      cast<CXXRecordDecl>(BaseClassTy->getDecl());
1631
1632    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1633    CXXRecordDecl *DerivedClassDecl =
1634      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1635
1636    LValue LV = EmitLValue(E->getSubExpr());
1637
1638    // Perform the base-to-derived conversion
1639    llvm::Value *Derived =
1640      GetAddressOfDerivedClass(LV.getAddress(), BaseClassDecl,
1641                               DerivedClassDecl, /*NullCheckValue=*/false);
1642
1643    return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
1644  }
1645  case CastExpr::CK_BitCast: {
1646    // This must be a reinterpret_cast (or c-style equivalent).
1647    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1648
1649    LValue LV = EmitLValue(E->getSubExpr());
1650    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1651                                           ConvertType(CE->getTypeAsWritten()));
1652    return LValue::MakeAddr(V, MakeQualifiers(E->getType()));
1653  }
1654  }
1655}
1656
1657LValue CodeGenFunction::EmitNullInitializationLValue(
1658                                              const CXXZeroInitValueExpr *E) {
1659  QualType Ty = E->getType();
1660  const llvm::Type *LTy = ConvertTypeForMem(Ty);
1661  llvm::AllocaInst *Alloc = CreateTempAlloca(LTy);
1662  CharUnits Align = getContext().getTypeAlignInChars(Ty);
1663  Alloc->setAlignment(Align.getQuantity());
1664  LValue lvalue = LValue::MakeAddr(Alloc, Qualifiers());
1665  EmitMemSetToZero(lvalue.getAddress(), Ty);
1666  return lvalue;
1667}
1668
1669//===--------------------------------------------------------------------===//
1670//                             Expression Emission
1671//===--------------------------------------------------------------------===//
1672
1673
1674RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1675                                     ReturnValueSlot ReturnValue) {
1676  // Builtins never have block type.
1677  if (E->getCallee()->getType()->isBlockPointerType())
1678    return EmitBlockCallExpr(E, ReturnValue);
1679
1680  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1681    return EmitCXXMemberCallExpr(CE, ReturnValue);
1682
1683  const Decl *TargetDecl = 0;
1684  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1685    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1686      TargetDecl = DRE->getDecl();
1687      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1688        if (unsigned builtinID = FD->getBuiltinID())
1689          return EmitBuiltinExpr(FD, builtinID, E);
1690    }
1691  }
1692
1693  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1694    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1695      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1696
1697  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1698    // C++ [expr.pseudo]p1:
1699    //   The result shall only be used as the operand for the function call
1700    //   operator (), and the result of such a call has type void. The only
1701    //   effect is the evaluation of the postfix-expression before the dot or
1702    //   arrow.
1703    EmitScalarExpr(E->getCallee());
1704    return RValue::get(0);
1705  }
1706
1707  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1708  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1709                  E->arg_begin(), E->arg_end(), TargetDecl);
1710}
1711
1712LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1713  // Comma expressions just emit their LHS then their RHS as an l-value.
1714  if (E->getOpcode() == BinaryOperator::Comma) {
1715    EmitAnyExpr(E->getLHS());
1716    EnsureInsertPoint();
1717    return EmitLValue(E->getRHS());
1718  }
1719
1720  if (E->getOpcode() == BinaryOperator::PtrMemD ||
1721      E->getOpcode() == BinaryOperator::PtrMemI)
1722    return EmitPointerToDataMemberBinaryExpr(E);
1723
1724  // Can only get l-value for binary operator expressions which are a
1725  // simple assignment of aggregate type.
1726  if (E->getOpcode() != BinaryOperator::Assign)
1727    return EmitUnsupportedLValue(E, "binary l-value expression");
1728
1729  if (!hasAggregateLLVMType(E->getType())) {
1730    // Emit the LHS as an l-value.
1731    LValue LV = EmitLValue(E->getLHS());
1732
1733    llvm::Value *RHS = EmitScalarExpr(E->getRHS());
1734    EmitStoreOfScalar(RHS, LV.getAddress(), LV.isVolatileQualified(),
1735                      E->getType());
1736    return LV;
1737  }
1738
1739  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1740  EmitAggExpr(E, Temp, false);
1741  // FIXME: Are these qualifiers correct?
1742  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1743}
1744
1745LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1746  RValue RV = EmitCallExpr(E);
1747
1748  if (!RV.isScalar())
1749    return LValue::MakeAddr(RV.getAggregateAddr(),MakeQualifiers(E->getType()));
1750
1751  assert(E->getCallReturnType()->isReferenceType() &&
1752         "Can't have a scalar return unless the return type is a "
1753         "reference type!");
1754
1755  return LValue::MakeAddr(RV.getScalarVal(), MakeQualifiers(E->getType()));
1756}
1757
1758LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1759  // FIXME: This shouldn't require another copy.
1760  llvm::Value *Temp = CreateTempAlloca(ConvertType(E->getType()));
1761  EmitAggExpr(E, Temp, false);
1762  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1763}
1764
1765LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1766  llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(E->getType()), "tmp");
1767  EmitCXXConstructExpr(Temp, E);
1768  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1769}
1770
1771LValue
1772CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1773  llvm::Value *Temp = EmitCXXTypeidExpr(E);
1774  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1775}
1776
1777LValue
1778CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1779  LValue LV = EmitLValue(E->getSubExpr());
1780  PushCXXTemporary(E->getTemporary(), LV.getAddress());
1781  return LV;
1782}
1783
1784LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1785  // Can only get l-value for message expression returning aggregate type
1786  RValue RV = EmitObjCMessageExpr(E);
1787  // FIXME: can this be volatile?
1788  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1789}
1790
1791llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1792                                             const ObjCIvarDecl *Ivar) {
1793  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1794}
1795
1796LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1797                                          llvm::Value *BaseValue,
1798                                          const ObjCIvarDecl *Ivar,
1799                                          unsigned CVRQualifiers) {
1800  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1801                                                   Ivar, CVRQualifiers);
1802}
1803
1804LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1805  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1806  llvm::Value *BaseValue = 0;
1807  const Expr *BaseExpr = E->getBase();
1808  Qualifiers BaseQuals;
1809  QualType ObjectTy;
1810  if (E->isArrow()) {
1811    BaseValue = EmitScalarExpr(BaseExpr);
1812    ObjectTy = BaseExpr->getType()->getPointeeType();
1813    BaseQuals = ObjectTy.getQualifiers();
1814  } else {
1815    LValue BaseLV = EmitLValue(BaseExpr);
1816    // FIXME: this isn't right for bitfields.
1817    BaseValue = BaseLV.getAddress();
1818    ObjectTy = BaseExpr->getType();
1819    BaseQuals = ObjectTy.getQualifiers();
1820  }
1821
1822  LValue LV =
1823    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1824                      BaseQuals.getCVRQualifiers());
1825  setObjCGCLValueClass(getContext(), E, LV);
1826  return LV;
1827}
1828
1829LValue
1830CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1831  // This is a special l-value that just issues sends when we load or store
1832  // through it.
1833  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1834}
1835
1836LValue CodeGenFunction::EmitObjCKVCRefLValue(
1837                                const ObjCImplicitSetterGetterRefExpr *E) {
1838  // This is a special l-value that just issues sends when we load or store
1839  // through it.
1840  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1841}
1842
1843LValue CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1844  return EmitUnsupportedLValue(E, "use of super");
1845}
1846
1847LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1848  // Can only get l-value for message expression returning aggregate type
1849  RValue RV = EmitAnyExprToTemp(E);
1850  // FIXME: can this be volatile?
1851  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1852}
1853
1854
1855LValue CodeGenFunction::EmitPointerToDataMemberLValue(const FieldDecl *Field) {
1856  const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(Field->getDeclContext());
1857  QualType NNSpecTy =
1858    getContext().getCanonicalType(
1859      getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(ClassDecl)));
1860  NNSpecTy = getContext().getPointerType(NNSpecTy);
1861  llvm::Value *V = llvm::Constant::getNullValue(ConvertType(NNSpecTy));
1862  LValue MemExpLV = EmitLValueForField(V, Field, /*Qualifiers=*/0);
1863  const llvm::Type *ResultType = ConvertType(getContext().getPointerDiffType());
1864  V = Builder.CreatePtrToInt(MemExpLV.getAddress(), ResultType, "datamember");
1865  return LValue::MakeAddr(V, MakeQualifiers(Field->getType()));
1866}
1867
1868RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
1869                                 ReturnValueSlot ReturnValue,
1870                                 CallExpr::const_arg_iterator ArgBeg,
1871                                 CallExpr::const_arg_iterator ArgEnd,
1872                                 const Decl *TargetDecl) {
1873  // Get the actual function type. The callee type will always be a pointer to
1874  // function type or a block pointer type.
1875  assert(CalleeType->isFunctionPointerType() &&
1876         "Call must have function pointer type!");
1877
1878  CalleeType = getContext().getCanonicalType(CalleeType);
1879
1880  QualType FnType = cast<PointerType>(CalleeType)->getPointeeType();
1881  QualType ResultType = cast<FunctionType>(FnType)->getResultType();
1882
1883  CallArgList Args;
1884  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
1885
1886  // FIXME: We should not need to do this, it should be part of the function
1887  // type.
1888  unsigned CallingConvention = 0;
1889  if (const llvm::Function *F =
1890      dyn_cast<llvm::Function>(Callee->stripPointerCasts()))
1891    CallingConvention = F->getCallingConv();
1892  return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args,
1893                                                 CallingConvention),
1894                  Callee, ReturnValue, Args, TargetDecl);
1895}
1896
1897LValue CodeGenFunction::
1898EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
1899  llvm::Value *BaseV;
1900  if (E->getOpcode() == BinaryOperator::PtrMemI)
1901    BaseV = EmitScalarExpr(E->getLHS());
1902  else
1903    BaseV = EmitLValue(E->getLHS()).getAddress();
1904  const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(getLLVMContext());
1905  BaseV = Builder.CreateBitCast(BaseV, i8Ty);
1906  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
1907  llvm::Value *AddV = Builder.CreateInBoundsGEP(BaseV, OffsetV, "add.ptr");
1908
1909  QualType Ty = E->getRHS()->getType();
1910  Ty = Ty->getAs<MemberPointerType>()->getPointeeType();
1911
1912  const llvm::Type *PType = ConvertType(getContext().getPointerType(Ty));
1913  AddV = Builder.CreateBitCast(AddV, PType);
1914  return LValue::MakeAddr(AddV, MakeQualifiers(Ty));
1915}
1916
1917