CGExpr.cpp revision a04efdf635d35d88e65041fad007225d8c8d64a5 
1//===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This contains code to emit Expr nodes as LLVM code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CodeGenFunction.h"
15#include "CodeGenModule.h"
16#include "CGCall.h"
17#include "CGRecordLayout.h"
18#include "CGObjCRuntime.h"
19#include "clang/AST/ASTContext.h"
20#include "clang/AST/DeclObjC.h"
21#include "llvm/Intrinsics.h"
22#include "clang/CodeGen/CodeGenOptions.h"
23#include "llvm/Target/TargetData.h"
24using namespace clang;
25using namespace CodeGen;
26
27//===--------------------------------------------------------------------===//
28//                        Miscellaneous Helper Methods
29//===--------------------------------------------------------------------===//
30
31/// CreateTempAlloca - This creates a alloca and inserts it into the entry
32/// block.
33llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
34                                                    const llvm::Twine &Name) {
35  if (!Builder.isNamePreserving())
36    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
37  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
38}
39
40void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
41                                     llvm::Value *Init) {
42  llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
43  llvm::BasicBlock *Block = AllocaInsertPt->getParent();
44  Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
45}
46
47llvm::Value *CodeGenFunction::CreateIRTemp(QualType Ty,
48                                           const llvm::Twine &Name) {
49  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
50  // FIXME: Should we prefer the preferred type alignment here?
51  CharUnits Align = getContext().getTypeAlignInChars(Ty);
52  Alloc->setAlignment(Align.getQuantity());
53  return Alloc;
54}
55
56llvm::Value *CodeGenFunction::CreateMemTemp(QualType Ty,
57                                            const llvm::Twine &Name) {
58  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
59  // FIXME: Should we prefer the preferred type alignment here?
60  CharUnits Align = getContext().getTypeAlignInChars(Ty);
61  Alloc->setAlignment(Align.getQuantity());
62  return Alloc;
63}
64
65/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
66/// expression and compare the result against zero, returning an Int1Ty value.
67llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
68  QualType BoolTy = getContext().BoolTy;
69  if (E->getType()->isMemberFunctionPointerType()) {
70    LValue LV = EmitAggExprToLValue(E);
71
72    // Get the pointer.
73    llvm::Value *FuncPtr = Builder.CreateStructGEP(LV.getAddress(), 0,
74                                                   "src.ptr");
75    FuncPtr = Builder.CreateLoad(FuncPtr);
76
77    llvm::Value *IsNotNull =
78      Builder.CreateICmpNE(FuncPtr,
79                            llvm::Constant::getNullValue(FuncPtr->getType()),
80                            "tobool");
81
82    return IsNotNull;
83  }
84  if (!E->getType()->isAnyComplexType())
85    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
86
87  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
88}
89
90/// EmitAnyExpr - Emit code to compute the specified expression which can have
91/// any type.  The result is returned as an RValue struct.  If this is an
92/// aggregate expression, the aggloc/agglocvolatile arguments indicate where the
93/// result should be returned.
94RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
95                                    bool IsAggLocVolatile, bool IgnoreResult,
96                                    bool IsInitializer) {
97  if (!hasAggregateLLVMType(E->getType()))
98    return RValue::get(EmitScalarExpr(E, IgnoreResult));
99  else if (E->getType()->isAnyComplexType())
100    return RValue::getComplex(EmitComplexExpr(E, false, false,
101                                              IgnoreResult, IgnoreResult));
102
103  EmitAggExpr(E, AggLoc, IsAggLocVolatile, IgnoreResult, IsInitializer);
104  return RValue::getAggregate(AggLoc, IsAggLocVolatile);
105}
106
107/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
108/// always be accessible even if no aggregate location is provided.
109RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E,
110                                          bool IsAggLocVolatile,
111                                          bool IsInitializer) {
112  llvm::Value *AggLoc = 0;
113
114  if (hasAggregateLLVMType(E->getType()) &&
115      !E->getType()->isAnyComplexType())
116    AggLoc = CreateMemTemp(E->getType(), "agg.tmp");
117  return EmitAnyExpr(E, AggLoc, IsAggLocVolatile, /*IgnoreResult=*/false,
118                     IsInitializer);
119}
120
121/// EmitAnyExprToMem - Evaluate an expression into a given memory
122/// location.
123void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
124                                       llvm::Value *Location,
125                                       bool IsLocationVolatile,
126                                       bool IsInit) {
127  if (E->getType()->isComplexType())
128    EmitComplexExprIntoAddr(E, Location, IsLocationVolatile);
129  else if (hasAggregateLLVMType(E->getType()))
130    EmitAggExpr(E, Location, IsLocationVolatile, /*Ignore*/ false, IsInit);
131  else {
132    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
133    LValue LV = LValue::MakeAddr(Location, MakeQualifiers(E->getType()));
134    EmitStoreThroughLValue(RV, LV, E->getType());
135  }
136}
137
138RValue CodeGenFunction::EmitReferenceBindingToExpr(const Expr* E,
139                                                   bool IsInitializer) {
140  bool ShouldDestroyTemporaries = false;
141  unsigned OldNumLiveTemporaries = 0;
142
143  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
144    E = DAE->getExpr();
145
146  if (const CXXExprWithTemporaries *TE = dyn_cast<CXXExprWithTemporaries>(E)) {
147    ShouldDestroyTemporaries = true;
148
149    // Keep track of the current cleanup stack depth.
150    OldNumLiveTemporaries = LiveTemporaries.size();
151
152    E = TE->getSubExpr();
153  }
154
155  RValue Val;
156  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
157    // Emit the expr as an lvalue.
158    LValue LV = EmitLValue(E);
159    if (LV.isSimple()) {
160      if (ShouldDestroyTemporaries) {
161        // Pop temporaries.
162        while (LiveTemporaries.size() > OldNumLiveTemporaries)
163          PopCXXTemporary();
164      }
165
166      return RValue::get(LV.getAddress());
167    }
168
169    Val = EmitLoadOfLValue(LV, E->getType());
170
171    if (ShouldDestroyTemporaries) {
172      // Pop temporaries.
173      while (LiveTemporaries.size() > OldNumLiveTemporaries)
174        PopCXXTemporary();
175    }
176  } else {
177    const CXXBaseSpecifierArray *BasePath = 0;
178    const CXXRecordDecl *DerivedClassDecl = 0;
179
180    if (const CastExpr *CE =
181          dyn_cast<CastExpr>(E->IgnoreParenNoopCasts(getContext()))) {
182      if (CE->getCastKind() == CastExpr::CK_DerivedToBase) {
183        E = CE->getSubExpr();
184
185        BasePath = &CE->getBasePath();
186        DerivedClassDecl =
187          cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
188      }
189    }
190
191    Val = EmitAnyExprToTemp(E, /*IsAggLocVolatile=*/false,
192                            IsInitializer);
193
194    if (ShouldDestroyTemporaries) {
195      // Pop temporaries.
196      while (LiveTemporaries.size() > OldNumLiveTemporaries)
197        PopCXXTemporary();
198    }
199
200    if (IsInitializer) {
201      // We might have to destroy the temporary variable.
202      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
203        if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
204          if (!ClassDecl->hasTrivialDestructor()) {
205            const CXXDestructorDecl *Dtor =
206              ClassDecl->getDestructor(getContext());
207
208            {
209              DelayedCleanupBlock Scope(*this);
210              EmitCXXDestructorCall(Dtor, Dtor_Complete,
211                                    Val.getAggregateAddr());
212
213              // Make sure to jump to the exit block.
214              EmitBranch(Scope.getCleanupExitBlock());
215            }
216            if (Exceptions) {
217              EHCleanupBlock Cleanup(*this);
218              EmitCXXDestructorCall(Dtor, Dtor_Complete,
219                                    Val.getAggregateAddr());
220            }
221          }
222        }
223      }
224    }
225
226    // Check if need to perform the derived-to-base cast.
227    if (BasePath) {
228      llvm::Value *Derived = Val.getAggregateAddr();
229      llvm::Value *Base =
230        GetAddressOfBaseClass(Derived, DerivedClassDecl, *BasePath,
231                              /*NullCheckValue=*/false);
232      return RValue::get(Base);
233    }
234  }
235
236  if (Val.isAggregate()) {
237    Val = RValue::get(Val.getAggregateAddr());
238  } else {
239    // Create a temporary variable that we can bind the reference to.
240    llvm::Value *Temp = CreateMemTemp(E->getType(), "reftmp");
241    if (Val.isScalar())
242      EmitStoreOfScalar(Val.getScalarVal(), Temp, false, E->getType());
243    else
244      StoreComplexToAddr(Val.getComplexVal(), Temp, false);
245    Val = RValue::get(Temp);
246  }
247
248  return Val;
249}
250
251
252/// getAccessedFieldNo - Given an encoded value and a result number, return the
253/// input field number being accessed.
254unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
255                                             const llvm::Constant *Elts) {
256  if (isa<llvm::ConstantAggregateZero>(Elts))
257    return 0;
258
259  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
260}
261
262void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
263  if (!CatchUndefined)
264    return;
265
266  const llvm::Type *Size_tTy
267    = llvm::IntegerType::get(VMContext, LLVMPointerWidth);
268  Address = Builder.CreateBitCast(Address, PtrToInt8Ty);
269
270  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, &Size_tTy, 1);
271  const llvm::IntegerType *Int1Ty = llvm::IntegerType::get(VMContext, 1);
272
273  // In time, people may want to control this and use a 1 here.
274  llvm::Value *Arg = llvm::ConstantInt::get(Int1Ty, 0);
275  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
276  llvm::BasicBlock *Cont = createBasicBlock();
277  llvm::BasicBlock *Check = createBasicBlock();
278  llvm::Value *NegativeOne = llvm::ConstantInt::get(Size_tTy, -1ULL);
279  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
280
281  EmitBlock(Check);
282  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
283                                        llvm::ConstantInt::get(Size_tTy, Size)),
284                       Cont, getTrapBB());
285  EmitBlock(Cont);
286}
287
288
289llvm::Value *CodeGenFunction::
290EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
291                        bool isInc, bool isPre) {
292  QualType ValTy = E->getSubExpr()->getType();
293  llvm::Value *InVal = EmitLoadOfLValue(LV, ValTy).getScalarVal();
294
295  int AmountVal = isInc ? 1 : -1;
296
297  if (ValTy->isPointerType() &&
298      ValTy->getAs<PointerType>()->isVariableArrayType()) {
299    // The amount of the addition/subtraction needs to account for the VLA size
300    ErrorUnsupported(E, "VLA pointer inc/dec");
301  }
302
303  llvm::Value *NextVal;
304  if (const llvm::PointerType *PT =
305      dyn_cast<llvm::PointerType>(InVal->getType())) {
306    llvm::Constant *Inc =
307    llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), AmountVal);
308    if (!isa<llvm::FunctionType>(PT->getElementType())) {
309      QualType PTEE = ValTy->getPointeeType();
310      if (const ObjCInterfaceType *OIT =
311          dyn_cast<ObjCInterfaceType>(PTEE)) {
312        // Handle interface types, which are not represented with a concrete
313        // type.
314        int size = getContext().getTypeSize(OIT) / 8;
315        if (!isInc)
316          size = -size;
317        Inc = llvm::ConstantInt::get(Inc->getType(), size);
318        const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
319        InVal = Builder.CreateBitCast(InVal, i8Ty);
320        NextVal = Builder.CreateGEP(InVal, Inc, "add.ptr");
321        llvm::Value *lhs = LV.getAddress();
322        lhs = Builder.CreateBitCast(lhs, llvm::PointerType::getUnqual(i8Ty));
323        LV = LValue::MakeAddr(lhs, MakeQualifiers(ValTy));
324      } else
325        NextVal = Builder.CreateInBoundsGEP(InVal, Inc, "ptrincdec");
326    } else {
327      const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(VMContext);
328      NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp");
329      NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec");
330      NextVal = Builder.CreateBitCast(NextVal, InVal->getType());
331    }
332  } else if (InVal->getType() == llvm::Type::getInt1Ty(VMContext) && isInc) {
333    // Bool++ is an interesting case, due to promotion rules, we get:
334    // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 ->
335    // Bool = ((int)Bool+1) != 0
336    // An interesting aspect of this is that increment is always true.
337    // Decrement does not have this property.
338    NextVal = llvm::ConstantInt::getTrue(VMContext);
339  } else if (isa<llvm::IntegerType>(InVal->getType())) {
340    NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal);
341
342    // Signed integer overflow is undefined behavior.
343    if (ValTy->isSignedIntegerType())
344      NextVal = Builder.CreateNSWAdd(InVal, NextVal, isInc ? "inc" : "dec");
345    else
346      NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec");
347  } else {
348    // Add the inc/dec to the real part.
349    if (InVal->getType()->isFloatTy())
350      NextVal =
351      llvm::ConstantFP::get(VMContext,
352                            llvm::APFloat(static_cast<float>(AmountVal)));
353    else if (InVal->getType()->isDoubleTy())
354      NextVal =
355      llvm::ConstantFP::get(VMContext,
356                            llvm::APFloat(static_cast<double>(AmountVal)));
357    else {
358      llvm::APFloat F(static_cast<float>(AmountVal));
359      bool ignored;
360      F.convert(Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
361                &ignored);
362      NextVal = llvm::ConstantFP::get(VMContext, F);
363    }
364    NextVal = Builder.CreateFAdd(InVal, NextVal, isInc ? "inc" : "dec");
365  }
366
367  // Store the updated result through the lvalue.
368  if (LV.isBitField())
369    EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy, &NextVal);
370  else
371    EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy);
372
373  // If this is a postinc, return the value read from memory, otherwise use the
374  // updated value.
375  return isPre ? NextVal : InVal;
376}
377
378
379CodeGenFunction::ComplexPairTy CodeGenFunction::
380EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
381                         bool isInc, bool isPre) {
382  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
383                                            LV.isVolatileQualified());
384
385  llvm::Value *NextVal;
386  if (isa<llvm::IntegerType>(InVal.first->getType())) {
387    uint64_t AmountVal = isInc ? 1 : -1;
388    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
389
390    // Add the inc/dec to the real part.
391    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
392  } else {
393    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
394    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
395    if (!isInc)
396      FVal.changeSign();
397    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
398
399    // Add the inc/dec to the real part.
400    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
401  }
402
403  ComplexPairTy IncVal(NextVal, InVal.second);
404
405  // Store the updated result through the lvalue.
406  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
407
408  // If this is a postinc, return the value read from memory, otherwise use the
409  // updated value.
410  return isPre ? IncVal : InVal;
411}
412
413
414//===----------------------------------------------------------------------===//
415//                         LValue Expression Emission
416//===----------------------------------------------------------------------===//
417
418RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
419  if (Ty->isVoidType())
420    return RValue::get(0);
421
422  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
423    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
424    llvm::Value *U = llvm::UndefValue::get(EltTy);
425    return RValue::getComplex(std::make_pair(U, U));
426  }
427
428  if (hasAggregateLLVMType(Ty)) {
429    const llvm::Type *LTy = llvm::PointerType::getUnqual(ConvertType(Ty));
430    return RValue::getAggregate(llvm::UndefValue::get(LTy));
431  }
432
433  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
434}
435
436RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
437                                              const char *Name) {
438  ErrorUnsupported(E, Name);
439  return GetUndefRValue(E->getType());
440}
441
442LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
443                                              const char *Name) {
444  ErrorUnsupported(E, Name);
445  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
446  return LValue::MakeAddr(llvm::UndefValue::get(Ty),
447                          MakeQualifiers(E->getType()));
448}
449
450LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
451  LValue LV = EmitLValue(E);
452  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
453    EmitCheck(LV.getAddress(), getContext().getTypeSize(E->getType()) / 8);
454  return LV;
455}
456
457/// EmitLValue - Emit code to compute a designator that specifies the location
458/// of the expression.
459///
460/// This can return one of two things: a simple address or a bitfield reference.
461/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
462/// an LLVM pointer type.
463///
464/// If this returns a bitfield reference, nothing about the pointee type of the
465/// LLVM value is known: For example, it may not be a pointer to an integer.
466///
467/// If this returns a normal address, and if the lvalue's C type is fixed size,
468/// this method guarantees that the returned pointer type will point to an LLVM
469/// type of the same size of the lvalue's type.  If the lvalue has a variable
470/// length type, this is not possible.
471///
472LValue CodeGenFunction::EmitLValue(const Expr *E) {
473  switch (E->getStmtClass()) {
474  default: return EmitUnsupportedLValue(E, "l-value expression");
475
476  case Expr::ObjCIsaExprClass:
477    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
478  case Expr::BinaryOperatorClass:
479    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
480  case Expr::CompoundAssignOperatorClass:
481    return EmitCompoundAssignOperatorLValue(cast<CompoundAssignOperator>(E));
482  case Expr::CallExprClass:
483  case Expr::CXXMemberCallExprClass:
484  case Expr::CXXOperatorCallExprClass:
485    return EmitCallExprLValue(cast<CallExpr>(E));
486  case Expr::VAArgExprClass:
487    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
488  case Expr::DeclRefExprClass:
489    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
490  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
491  case Expr::PredefinedExprClass:
492    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
493  case Expr::StringLiteralClass:
494    return EmitStringLiteralLValue(cast<StringLiteral>(E));
495  case Expr::ObjCEncodeExprClass:
496    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
497
498  case Expr::BlockDeclRefExprClass:
499    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
500
501  case Expr::CXXTemporaryObjectExprClass:
502  case Expr::CXXConstructExprClass:
503    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
504  case Expr::CXXBindTemporaryExprClass:
505    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
506  case Expr::CXXExprWithTemporariesClass:
507    return EmitCXXExprWithTemporariesLValue(cast<CXXExprWithTemporaries>(E));
508  case Expr::CXXZeroInitValueExprClass:
509    return EmitNullInitializationLValue(cast<CXXZeroInitValueExpr>(E));
510  case Expr::CXXDefaultArgExprClass:
511    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
512  case Expr::CXXTypeidExprClass:
513    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
514
515  case Expr::ObjCMessageExprClass:
516    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
517  case Expr::ObjCIvarRefExprClass:
518    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
519  case Expr::ObjCPropertyRefExprClass:
520    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
521  case Expr::ObjCImplicitSetterGetterRefExprClass:
522    return EmitObjCKVCRefLValue(cast<ObjCImplicitSetterGetterRefExpr>(E));
523  case Expr::ObjCSuperExprClass:
524    return EmitObjCSuperExprLValue(cast<ObjCSuperExpr>(E));
525
526  case Expr::StmtExprClass:
527    return EmitStmtExprLValue(cast<StmtExpr>(E));
528  case Expr::UnaryOperatorClass:
529    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
530  case Expr::ArraySubscriptExprClass:
531    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
532  case Expr::ExtVectorElementExprClass:
533    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
534  case Expr::MemberExprClass:
535    return EmitMemberExpr(cast<MemberExpr>(E));
536  case Expr::CompoundLiteralExprClass:
537    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
538  case Expr::ConditionalOperatorClass:
539    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
540  case Expr::ChooseExprClass:
541    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
542  case Expr::ImplicitCastExprClass:
543  case Expr::CStyleCastExprClass:
544  case Expr::CXXFunctionalCastExprClass:
545  case Expr::CXXStaticCastExprClass:
546  case Expr::CXXDynamicCastExprClass:
547  case Expr::CXXReinterpretCastExprClass:
548  case Expr::CXXConstCastExprClass:
549    return EmitCastLValue(cast<CastExpr>(E));
550  }
551}
552
553llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
554                                               QualType Ty) {
555  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
556  if (Volatile)
557    Load->setVolatile(true);
558
559  // Bool can have different representation in memory than in registers.
560  llvm::Value *V = Load;
561  if (Ty->isBooleanType())
562    if (V->getType() != llvm::Type::getInt1Ty(VMContext))
563      V = Builder.CreateTrunc(V, llvm::Type::getInt1Ty(VMContext), "tobool");
564
565  return V;
566}
567
568void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
569                                        bool Volatile, QualType Ty) {
570
571  if (Ty->isBooleanType()) {
572    // Bool can have different representation in memory than in registers.
573    const llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
574    Value = Builder.CreateIntCast(Value, DstPtr->getElementType(), false);
575  }
576  Builder.CreateStore(Value, Addr, Volatile);
577}
578
579/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
580/// method emits the address of the lvalue, then loads the result as an rvalue,
581/// returning the rvalue.
582RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
583  if (LV.isObjCWeak()) {
584    // load of a __weak object.
585    llvm::Value *AddrWeakObj = LV.getAddress();
586    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
587                                                             AddrWeakObj));
588  }
589
590  if (LV.isSimple()) {
591    llvm::Value *Ptr = LV.getAddress();
592    const llvm::Type *EltTy =
593      cast<llvm::PointerType>(Ptr->getType())->getElementType();
594
595    // Simple scalar l-value.
596    //
597    // FIXME: We shouldn't have to use isSingleValueType here.
598    if (EltTy->isSingleValueType())
599      return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
600                                          ExprType));
601
602    assert(ExprType->isFunctionType() && "Unknown scalar value");
603    return RValue::get(Ptr);
604  }
605
606  if (LV.isVectorElt()) {
607    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
608                                          LV.isVolatileQualified(), "tmp");
609    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
610                                                    "vecext"));
611  }
612
613  // If this is a reference to a subset of the elements of a vector, either
614  // shuffle the input or extract/insert them as appropriate.
615  if (LV.isExtVectorElt())
616    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
617
618  if (LV.isBitField())
619    return EmitLoadOfBitfieldLValue(LV, ExprType);
620
621  if (LV.isPropertyRef())
622    return EmitLoadOfPropertyRefLValue(LV, ExprType);
623
624  assert(LV.isKVCRef() && "Unknown LValue type!");
625  return EmitLoadOfKVCRefLValue(LV, ExprType);
626}
627
628RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
629                                                 QualType ExprType) {
630  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
631
632  // Get the output type.
633  const llvm::Type *ResLTy = ConvertType(ExprType);
634  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
635
636  // Compute the result as an OR of all of the individual component accesses.
637  llvm::Value *Res = 0;
638  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
639    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
640
641    // Get the field pointer.
642    llvm::Value *Ptr = LV.getBitFieldBaseAddr();
643
644    // Only offset by the field index if used, so that incoming values are not
645    // required to be structures.
646    if (AI.FieldIndex)
647      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
648
649    // Offset by the byte offset, if used.
650    if (AI.FieldByteOffset) {
651      const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
652      Ptr = Builder.CreateBitCast(Ptr, i8PTy);
653      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
654    }
655
656    // Cast to the access type.
657    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(VMContext, AI.AccessWidth,
658                                                    ExprType.getAddressSpace());
659    Ptr = Builder.CreateBitCast(Ptr, PTy);
660
661    // Perform the load.
662    llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
663    if (AI.AccessAlignment)
664      Load->setAlignment(AI.AccessAlignment);
665
666    // Shift out unused low bits and mask out unused high bits.
667    llvm::Value *Val = Load;
668    if (AI.FieldBitStart)
669      Val = Builder.CreateLShr(Load, AI.FieldBitStart);
670    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
671                                                            AI.TargetBitWidth),
672                            "bf.clear");
673
674    // Extend or truncate to the target size.
675    if (AI.AccessWidth < ResSizeInBits)
676      Val = Builder.CreateZExt(Val, ResLTy);
677    else if (AI.AccessWidth > ResSizeInBits)
678      Val = Builder.CreateTrunc(Val, ResLTy);
679
680    // Shift into place, and OR into the result.
681    if (AI.TargetBitOffset)
682      Val = Builder.CreateShl(Val, AI.TargetBitOffset);
683    Res = Res ? Builder.CreateOr(Res, Val) : Val;
684  }
685
686  // If the bit-field is signed, perform the sign-extension.
687  //
688  // FIXME: This can easily be folded into the load of the high bits, which
689  // could also eliminate the mask of high bits in some situations.
690  if (Info.isSigned()) {
691    unsigned ExtraBits = ResSizeInBits - Info.getSize();
692    if (ExtraBits)
693      Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
694                               ExtraBits, "bf.val.sext");
695  }
696
697  return RValue::get(Res);
698}
699
700RValue CodeGenFunction::EmitLoadOfPropertyRefLValue(LValue LV,
701                                                    QualType ExprType) {
702  return EmitObjCPropertyGet(LV.getPropertyRefExpr());
703}
704
705RValue CodeGenFunction::EmitLoadOfKVCRefLValue(LValue LV,
706                                               QualType ExprType) {
707  return EmitObjCPropertyGet(LV.getKVCRefExpr());
708}
709
710// If this is a reference to a subset of the elements of a vector, create an
711// appropriate shufflevector.
712RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
713                                                         QualType ExprType) {
714  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
715                                        LV.isVolatileQualified(), "tmp");
716
717  const llvm::Constant *Elts = LV.getExtVectorElts();
718
719  // If the result of the expression is a non-vector type, we must be extracting
720  // a single element.  Just codegen as an extractelement.
721  const VectorType *ExprVT = ExprType->getAs<VectorType>();
722  if (!ExprVT) {
723    unsigned InIdx = getAccessedFieldNo(0, Elts);
724    llvm::Value *Elt = llvm::ConstantInt::get(
725                                      llvm::Type::getInt32Ty(VMContext), InIdx);
726    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
727  }
728
729  // Always use shuffle vector to try to retain the original program structure
730  unsigned NumResultElts = ExprVT->getNumElements();
731
732  llvm::SmallVector<llvm::Constant*, 4> Mask;
733  for (unsigned i = 0; i != NumResultElts; ++i) {
734    unsigned InIdx = getAccessedFieldNo(i, Elts);
735    Mask.push_back(llvm::ConstantInt::get(
736                                     llvm::Type::getInt32Ty(VMContext), InIdx));
737  }
738
739  llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
740  Vec = Builder.CreateShuffleVector(Vec,
741                                    llvm::UndefValue::get(Vec->getType()),
742                                    MaskV, "tmp");
743  return RValue::get(Vec);
744}
745
746
747
748/// EmitStoreThroughLValue - Store the specified rvalue into the specified
749/// lvalue, where both are guaranteed to the have the same type, and that type
750/// is 'Ty'.
751void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
752                                             QualType Ty) {
753  if (!Dst.isSimple()) {
754    if (Dst.isVectorElt()) {
755      // Read/modify/write the vector, inserting the new element.
756      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
757                                            Dst.isVolatileQualified(), "tmp");
758      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
759                                        Dst.getVectorIdx(), "vecins");
760      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
761      return;
762    }
763
764    // If this is an update of extended vector elements, insert them as
765    // appropriate.
766    if (Dst.isExtVectorElt())
767      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
768
769    if (Dst.isBitField())
770      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
771
772    if (Dst.isPropertyRef())
773      return EmitStoreThroughPropertyRefLValue(Src, Dst, Ty);
774
775    assert(Dst.isKVCRef() && "Unknown LValue type");
776    return EmitStoreThroughKVCRefLValue(Src, Dst, Ty);
777  }
778
779  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
780    // load of a __weak object.
781    llvm::Value *LvalueDst = Dst.getAddress();
782    llvm::Value *src = Src.getScalarVal();
783     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
784    return;
785  }
786
787  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
788    // load of a __strong object.
789    llvm::Value *LvalueDst = Dst.getAddress();
790    llvm::Value *src = Src.getScalarVal();
791    if (Dst.isObjCIvar()) {
792      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
793      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
794      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
795      llvm::Value *dst = RHS;
796      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
797      llvm::Value *LHS =
798        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
799      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
800      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
801                                              BytesBetween);
802    } else if (Dst.isGlobalObjCRef())
803      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst);
804    else
805      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
806    return;
807  }
808
809  assert(Src.isScalar() && "Can't emit an agg store with this method");
810  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
811                    Dst.isVolatileQualified(), Ty);
812}
813
814void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
815                                                     QualType Ty,
816                                                     llvm::Value **Result) {
817  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
818
819  // Get the output type.
820  const llvm::Type *ResLTy = ConvertTypeForMem(Ty);
821  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
822
823  // Get the source value, truncated to the width of the bit-field.
824  llvm::Value *SrcVal = Src.getScalarVal();
825
826  if (Ty->isBooleanType())
827    SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
828
829  SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
830                                                                Info.getSize()),
831                             "bf.value");
832
833  // Return the new value of the bit-field, if requested.
834  if (Result) {
835    // Cast back to the proper type for result.
836    const llvm::Type *SrcTy = Src.getScalarVal()->getType();
837    llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
838                                                   "bf.reload.val");
839
840    // Sign extend if necessary.
841    if (Info.isSigned()) {
842      unsigned ExtraBits = ResSizeInBits - Info.getSize();
843      if (ExtraBits)
844        ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
845                                       ExtraBits, "bf.reload.sext");
846    }
847
848    *Result = ReloadVal;
849  }
850
851  // Iterate over the components, writing each piece to memory.
852  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
853    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
854
855    // Get the field pointer.
856    llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
857
858    // Only offset by the field index if used, so that incoming values are not
859    // required to be structures.
860    if (AI.FieldIndex)
861      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
862
863    // Offset by the byte offset, if used.
864    if (AI.FieldByteOffset) {
865      const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
866      Ptr = Builder.CreateBitCast(Ptr, i8PTy);
867      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
868    }
869
870    // Cast to the access type.
871    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(VMContext, AI.AccessWidth,
872                                                     Ty.getAddressSpace());
873    Ptr = Builder.CreateBitCast(Ptr, PTy);
874
875    // Extract the piece of the bit-field value to write in this access, limited
876    // to the values that are part of this access.
877    llvm::Value *Val = SrcVal;
878    if (AI.TargetBitOffset)
879      Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
880    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
881                                                            AI.TargetBitWidth));
882
883    // Extend or truncate to the access size.
884    const llvm::Type *AccessLTy =
885      llvm::Type::getIntNTy(VMContext, AI.AccessWidth);
886    if (ResSizeInBits < AI.AccessWidth)
887      Val = Builder.CreateZExt(Val, AccessLTy);
888    else if (ResSizeInBits > AI.AccessWidth)
889      Val = Builder.CreateTrunc(Val, AccessLTy);
890
891    // Shift into the position in memory.
892    if (AI.FieldBitStart)
893      Val = Builder.CreateShl(Val, AI.FieldBitStart);
894
895    // If necessary, load and OR in bits that are outside of the bit-field.
896    if (AI.TargetBitWidth != AI.AccessWidth) {
897      llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
898      if (AI.AccessAlignment)
899        Load->setAlignment(AI.AccessAlignment);
900
901      // Compute the mask for zeroing the bits that are part of the bit-field.
902      llvm::APInt InvMask =
903        ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
904                                 AI.FieldBitStart + AI.TargetBitWidth);
905
906      // Apply the mask and OR in to the value to write.
907      Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
908    }
909
910    // Write the value.
911    llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
912                                                 Dst.isVolatileQualified());
913    if (AI.AccessAlignment)
914      Store->setAlignment(AI.AccessAlignment);
915  }
916}
917
918void CodeGenFunction::EmitStoreThroughPropertyRefLValue(RValue Src,
919                                                        LValue Dst,
920                                                        QualType Ty) {
921  EmitObjCPropertySet(Dst.getPropertyRefExpr(), Src);
922}
923
924void CodeGenFunction::EmitStoreThroughKVCRefLValue(RValue Src,
925                                                   LValue Dst,
926                                                   QualType Ty) {
927  EmitObjCPropertySet(Dst.getKVCRefExpr(), Src);
928}
929
930void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
931                                                               LValue Dst,
932                                                               QualType Ty) {
933  // This access turns into a read/modify/write of the vector.  Load the input
934  // value now.
935  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
936                                        Dst.isVolatileQualified(), "tmp");
937  const llvm::Constant *Elts = Dst.getExtVectorElts();
938
939  llvm::Value *SrcVal = Src.getScalarVal();
940
941  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
942    unsigned NumSrcElts = VTy->getNumElements();
943    unsigned NumDstElts =
944       cast<llvm::VectorType>(Vec->getType())->getNumElements();
945    if (NumDstElts == NumSrcElts) {
946      // Use shuffle vector is the src and destination are the same number of
947      // elements and restore the vector mask since it is on the side it will be
948      // stored.
949      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
950      for (unsigned i = 0; i != NumSrcElts; ++i) {
951        unsigned InIdx = getAccessedFieldNo(i, Elts);
952        Mask[InIdx] = llvm::ConstantInt::get(
953                                          llvm::Type::getInt32Ty(VMContext), i);
954      }
955
956      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
957      Vec = Builder.CreateShuffleVector(SrcVal,
958                                        llvm::UndefValue::get(Vec->getType()),
959                                        MaskV, "tmp");
960    } else if (NumDstElts > NumSrcElts) {
961      // Extended the source vector to the same length and then shuffle it
962      // into the destination.
963      // FIXME: since we're shuffling with undef, can we just use the indices
964      //        into that?  This could be simpler.
965      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
966      const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
967      unsigned i;
968      for (i = 0; i != NumSrcElts; ++i)
969        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
970      for (; i != NumDstElts; ++i)
971        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
972      llvm::Value *ExtMaskV = llvm::ConstantVector::get(&ExtMask[0],
973                                                        ExtMask.size());
974      llvm::Value *ExtSrcVal =
975        Builder.CreateShuffleVector(SrcVal,
976                                    llvm::UndefValue::get(SrcVal->getType()),
977                                    ExtMaskV, "tmp");
978      // build identity
979      llvm::SmallVector<llvm::Constant*, 4> Mask;
980      for (unsigned i = 0; i != NumDstElts; ++i)
981        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
982
983      // modify when what gets shuffled in
984      for (unsigned i = 0; i != NumSrcElts; ++i) {
985        unsigned Idx = getAccessedFieldNo(i, Elts);
986        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
987      }
988      llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
989      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
990    } else {
991      // We should never shorten the vector
992      assert(0 && "unexpected shorten vector length");
993    }
994  } else {
995    // If the Src is a scalar (not a vector) it must be updating one element.
996    unsigned InIdx = getAccessedFieldNo(0, Elts);
997    const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
998    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
999    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
1000  }
1001
1002  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1003}
1004
1005// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1006// generating write-barries API. It is currently a global, ivar,
1007// or neither.
1008static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1009                                 LValue &LV) {
1010  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
1011    return;
1012
1013  if (isa<ObjCIvarRefExpr>(E)) {
1014    LV.SetObjCIvar(LV, true);
1015    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1016    LV.setBaseIvarExp(Exp->getBase());
1017    LV.SetObjCArray(LV, E->getType()->isArrayType());
1018    return;
1019  }
1020
1021  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1022    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1023      if ((VD->isBlockVarDecl() && !VD->hasLocalStorage()) ||
1024          VD->isFileVarDecl())
1025        LV.SetGlobalObjCRef(LV, true);
1026    }
1027    LV.SetObjCArray(LV, E->getType()->isArrayType());
1028    return;
1029  }
1030
1031  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1032    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1033    return;
1034  }
1035
1036  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1037    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1038    if (LV.isObjCIvar()) {
1039      // If cast is to a structure pointer, follow gcc's behavior and make it
1040      // a non-ivar write-barrier.
1041      QualType ExpTy = E->getType();
1042      if (ExpTy->isPointerType())
1043        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1044      if (ExpTy->isRecordType())
1045        LV.SetObjCIvar(LV, false);
1046    }
1047    return;
1048  }
1049  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1050    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1051    return;
1052  }
1053
1054  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1055    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1056    return;
1057  }
1058
1059  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1060    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1061    if (LV.isObjCIvar() && !LV.isObjCArray())
1062      // Using array syntax to assigning to what an ivar points to is not
1063      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1064      LV.SetObjCIvar(LV, false);
1065    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1066      // Using array syntax to assigning to what global points to is not
1067      // same as assigning to the global itself. {id *G;} G[i] = 0;
1068      LV.SetGlobalObjCRef(LV, false);
1069    return;
1070  }
1071
1072  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1073    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1074    // We don't know if member is an 'ivar', but this flag is looked at
1075    // only in the context of LV.isObjCIvar().
1076    LV.SetObjCArray(LV, E->getType()->isArrayType());
1077    return;
1078  }
1079}
1080
1081static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1082                                      const Expr *E, const VarDecl *VD) {
1083  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1084         "Var decl must have external storage or be a file var decl!");
1085
1086  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1087  if (VD->getType()->isReferenceType())
1088    V = CGF.Builder.CreateLoad(V, "tmp");
1089  LValue LV = LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1090  setObjCGCLValueClass(CGF.getContext(), E, LV);
1091  return LV;
1092}
1093
1094static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1095                                      const Expr *E, const FunctionDecl *FD) {
1096  llvm::Value* V = CGF.CGM.GetAddrOfFunction(FD);
1097  if (!FD->hasPrototype()) {
1098    if (const FunctionProtoType *Proto =
1099            FD->getType()->getAs<FunctionProtoType>()) {
1100      // Ugly case: for a K&R-style definition, the type of the definition
1101      // isn't the same as the type of a use.  Correct for this with a
1102      // bitcast.
1103      QualType NoProtoType =
1104          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1105      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1106      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1107    }
1108  }
1109  return LValue::MakeAddr(V, CGF.MakeQualifiers(E->getType()));
1110}
1111
1112LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1113  const NamedDecl *ND = E->getDecl();
1114
1115  if (ND->hasAttr<WeakRefAttr>()) {
1116    const ValueDecl* VD = cast<ValueDecl>(ND);
1117    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1118
1119    Qualifiers Quals = MakeQualifiers(E->getType());
1120    LValue LV = LValue::MakeAddr(Aliasee, Quals);
1121
1122    return LV;
1123  }
1124
1125  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1126
1127    // Check if this is a global variable.
1128    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1129      return EmitGlobalVarDeclLValue(*this, E, VD);
1130
1131    bool NonGCable = VD->hasLocalStorage() && !VD->hasAttr<BlocksAttr>();
1132
1133    llvm::Value *V = LocalDeclMap[VD];
1134    if (!V && getContext().getLangOptions().CPlusPlus &&
1135        VD->isStaticLocal())
1136      V = CGM.getStaticLocalDeclAddress(VD);
1137    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1138
1139    Qualifiers Quals = MakeQualifiers(E->getType());
1140    // local variables do not get their gc attribute set.
1141    // local static?
1142    if (NonGCable) Quals.removeObjCGCAttr();
1143
1144    if (VD->hasAttr<BlocksAttr>()) {
1145      V = Builder.CreateStructGEP(V, 1, "forwarding");
1146      V = Builder.CreateLoad(V);
1147      V = Builder.CreateStructGEP(V, getByRefValueLLVMField(VD),
1148                                  VD->getNameAsString());
1149    }
1150    if (VD->getType()->isReferenceType())
1151      V = Builder.CreateLoad(V, "tmp");
1152    LValue LV = LValue::MakeAddr(V, Quals);
1153    LValue::SetObjCNonGC(LV, NonGCable);
1154    setObjCGCLValueClass(getContext(), E, LV);
1155    return LV;
1156  }
1157
1158  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1159    return EmitFunctionDeclLValue(*this, E, FD);
1160
1161  // FIXME: the qualifier check does not seem sufficient here
1162  if (E->getQualifier()) {
1163    const FieldDecl *FD = cast<FieldDecl>(ND);
1164    llvm::Value *V = CGM.EmitPointerToDataMember(FD);
1165
1166    return LValue::MakeAddr(V, MakeQualifiers(FD->getType()));
1167  }
1168
1169  assert(false && "Unhandled DeclRefExpr");
1170
1171  // an invalid LValue, but the assert will
1172  // ensure that this point is never reached.
1173  return LValue();
1174}
1175
1176LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1177  return LValue::MakeAddr(GetAddrOfBlockDecl(E), MakeQualifiers(E->getType()));
1178}
1179
1180LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1181  // __extension__ doesn't affect lvalue-ness.
1182  if (E->getOpcode() == UnaryOperator::Extension)
1183    return EmitLValue(E->getSubExpr());
1184
1185  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1186  switch (E->getOpcode()) {
1187  default: assert(0 && "Unknown unary operator lvalue!");
1188  case UnaryOperator::Deref: {
1189    QualType T = E->getSubExpr()->getType()->getPointeeType();
1190    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1191
1192    Qualifiers Quals = MakeQualifiers(T);
1193    Quals.setAddressSpace(ExprTy.getAddressSpace());
1194
1195    LValue LV = LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()), Quals);
1196    // We should not generate __weak write barrier on indirect reference
1197    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1198    // But, we continue to generate __strong write barrier on indirect write
1199    // into a pointer to object.
1200    if (getContext().getLangOptions().ObjC1 &&
1201        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1202        LV.isObjCWeak())
1203      LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1204    return LV;
1205  }
1206  case UnaryOperator::Real:
1207  case UnaryOperator::Imag: {
1208    LValue LV = EmitLValue(E->getSubExpr());
1209    unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
1210    return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
1211                                                    Idx, "idx"),
1212                            MakeQualifiers(ExprTy));
1213  }
1214  case UnaryOperator::PreInc:
1215  case UnaryOperator::PreDec: {
1216    LValue LV = EmitLValue(E->getSubExpr());
1217    bool isInc = E->getOpcode() == UnaryOperator::PreInc;
1218
1219    if (E->getType()->isAnyComplexType())
1220      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1221    else
1222      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1223    return LV;
1224  }
1225  }
1226}
1227
1228LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1229  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromLiteral(E),
1230                          Qualifiers());
1231}
1232
1233LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1234  return LValue::MakeAddr(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1235                          Qualifiers());
1236}
1237
1238
1239LValue CodeGenFunction::EmitPredefinedFunctionName(unsigned Type) {
1240  std::string GlobalVarName;
1241
1242  switch (Type) {
1243  default: assert(0 && "Invalid type");
1244  case PredefinedExpr::Func:
1245    GlobalVarName = "__func__.";
1246    break;
1247  case PredefinedExpr::Function:
1248    GlobalVarName = "__FUNCTION__.";
1249    break;
1250  case PredefinedExpr::PrettyFunction:
1251    GlobalVarName = "__PRETTY_FUNCTION__.";
1252    break;
1253  }
1254
1255  llvm::StringRef FnName = CurFn->getName();
1256  if (FnName.startswith("\01"))
1257    FnName = FnName.substr(1);
1258  GlobalVarName += FnName;
1259
1260  std::string FunctionName =
1261    PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurCodeDecl);
1262
1263  llvm::Constant *C =
1264    CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1265  return LValue::MakeAddr(C, Qualifiers());
1266}
1267
1268LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1269  switch (E->getIdentType()) {
1270  default:
1271    return EmitUnsupportedLValue(E, "predefined expression");
1272  case PredefinedExpr::Func:
1273  case PredefinedExpr::Function:
1274  case PredefinedExpr::PrettyFunction:
1275    return EmitPredefinedFunctionName(E->getIdentType());
1276  }
1277}
1278
1279llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1280  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1281
1282  // If we are not optimzing, don't collapse all calls to trap in the function
1283  // to the same call, that way, in the debugger they can see which operation
1284  // did in fact fail.  If we are optimizing, we collpase all call to trap down
1285  // to just one per function to save on codesize.
1286  if (GCO.OptimizationLevel
1287      && TrapBB)
1288    return TrapBB;
1289
1290  llvm::BasicBlock *Cont = 0;
1291  if (HaveInsertPoint()) {
1292    Cont = createBasicBlock("cont");
1293    EmitBranch(Cont);
1294  }
1295  TrapBB = createBasicBlock("trap");
1296  EmitBlock(TrapBB);
1297
1298  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1299  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1300  TrapCall->setDoesNotReturn();
1301  TrapCall->setDoesNotThrow();
1302  Builder.CreateUnreachable();
1303
1304  if (Cont)
1305    EmitBlock(Cont);
1306  return TrapBB;
1307}
1308
1309LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1310  // The index must always be an integer, which is not an aggregate.  Emit it.
1311  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1312  QualType IdxTy  = E->getIdx()->getType();
1313  bool IdxSigned = IdxTy->isSignedIntegerType();
1314
1315  // If the base is a vector type, then we are forming a vector element lvalue
1316  // with this subscript.
1317  if (E->getBase()->getType()->isVectorType()) {
1318    // Emit the vector as an lvalue to get its address.
1319    LValue LHS = EmitLValue(E->getBase());
1320    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1321    Idx = Builder.CreateIntCast(Idx,
1322                          llvm::Type::getInt32Ty(VMContext), IdxSigned, "vidx");
1323    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1324                                 E->getBase()->getType().getCVRQualifiers());
1325  }
1326
1327  // The base must be a pointer, which is not an aggregate.  Emit it.
1328  llvm::Value *Base = EmitScalarExpr(E->getBase());
1329
1330  // Extend or truncate the index type to 32 or 64-bits.
1331  unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
1332  if (IdxBitwidth != LLVMPointerWidth)
1333    Idx = Builder.CreateIntCast(Idx,
1334                            llvm::IntegerType::get(VMContext, LLVMPointerWidth),
1335                                IdxSigned, "idxprom");
1336
1337  // FIXME: As llvm implements the object size checking, this can come out.
1338  if (CatchUndefined) {
1339    if (const ImplicitCastExpr *ICE=dyn_cast<ImplicitCastExpr>(E->getBase())) {
1340      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1341        if (ICE->getCastKind() == CastExpr::CK_ArrayToPointerDecay) {
1342          if (const ConstantArrayType *CAT
1343              = getContext().getAsConstantArrayType(DRE->getType())) {
1344            llvm::APInt Size = CAT->getSize();
1345            llvm::BasicBlock *Cont = createBasicBlock("cont");
1346            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1347                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1348                                 Cont, getTrapBB());
1349            EmitBlock(Cont);
1350          }
1351        }
1352      }
1353    }
1354  }
1355
1356  // We know that the pointer points to a type of the correct size, unless the
1357  // size is a VLA or Objective-C interface.
1358  llvm::Value *Address = 0;
1359  if (const VariableArrayType *VAT =
1360        getContext().getAsVariableArrayType(E->getType())) {
1361    llvm::Value *VLASize = GetVLASize(VAT);
1362
1363    Idx = Builder.CreateMul(Idx, VLASize);
1364
1365    QualType BaseType = getContext().getBaseElementType(VAT);
1366
1367    CharUnits BaseTypeSize = getContext().getTypeSizeInChars(BaseType);
1368    Idx = Builder.CreateUDiv(Idx,
1369                             llvm::ConstantInt::get(Idx->getType(),
1370                                 BaseTypeSize.getQuantity()));
1371    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1372  } else if (const ObjCInterfaceType *OIT =
1373             dyn_cast<ObjCInterfaceType>(E->getType())) {
1374    llvm::Value *InterfaceSize =
1375      llvm::ConstantInt::get(Idx->getType(),
1376          getContext().getTypeSizeInChars(OIT).getQuantity());
1377
1378    Idx = Builder.CreateMul(Idx, InterfaceSize);
1379
1380    const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(VMContext);
1381    Address = Builder.CreateGEP(Builder.CreateBitCast(Base, i8PTy),
1382                                Idx, "arrayidx");
1383    Address = Builder.CreateBitCast(Address, Base->getType());
1384  } else {
1385    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1386  }
1387
1388  QualType T = E->getBase()->getType()->getPointeeType();
1389  assert(!T.isNull() &&
1390         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1391
1392  Qualifiers Quals = MakeQualifiers(T);
1393  Quals.setAddressSpace(E->getBase()->getType().getAddressSpace());
1394
1395  LValue LV = LValue::MakeAddr(Address, Quals);
1396  if (getContext().getLangOptions().ObjC1 &&
1397      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1398    LValue::SetObjCNonGC(LV, !E->isOBJCGCCandidate(getContext()));
1399    setObjCGCLValueClass(getContext(), E, LV);
1400  }
1401  return LV;
1402}
1403
1404static
1405llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1406                                       llvm::SmallVector<unsigned, 4> &Elts) {
1407  llvm::SmallVector<llvm::Constant*, 4> CElts;
1408
1409  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1410    CElts.push_back(llvm::ConstantInt::get(
1411                                   llvm::Type::getInt32Ty(VMContext), Elts[i]));
1412
1413  return llvm::ConstantVector::get(&CElts[0], CElts.size());
1414}
1415
1416LValue CodeGenFunction::
1417EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1418  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1419
1420  // Emit the base vector as an l-value.
1421  LValue Base;
1422
1423  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1424  if (E->isArrow()) {
1425    // If it is a pointer to a vector, emit the address and form an lvalue with
1426    // it.
1427    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1428    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1429    Qualifiers Quals = MakeQualifiers(PT->getPointeeType());
1430    Quals.removeObjCGCAttr();
1431    Base = LValue::MakeAddr(Ptr, Quals);
1432  } else if (E->getBase()->isLvalue(getContext()) == Expr::LV_Valid) {
1433    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1434    // emit the base as an lvalue.
1435    assert(E->getBase()->getType()->isVectorType());
1436    Base = EmitLValue(E->getBase());
1437  } else {
1438    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1439    assert(E->getBase()->getType()->getAs<VectorType>() &&
1440           "Result must be a vector");
1441    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1442
1443    // Store the vector to memory (because LValue wants an address).
1444    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1445    Builder.CreateStore(Vec, VecMem);
1446    Base = LValue::MakeAddr(VecMem, Qualifiers());
1447  }
1448
1449  // Encode the element access list into a vector of unsigned indices.
1450  llvm::SmallVector<unsigned, 4> Indices;
1451  E->getEncodedElementAccess(Indices);
1452
1453  if (Base.isSimple()) {
1454    llvm::Constant *CV = GenerateConstantVector(VMContext, Indices);
1455    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1456                                    Base.getVRQualifiers());
1457  }
1458  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1459
1460  llvm::Constant *BaseElts = Base.getExtVectorElts();
1461  llvm::SmallVector<llvm::Constant *, 4> CElts;
1462
1463  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1464    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1465      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1466    else
1467      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1468  }
1469  llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
1470  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1471                                  Base.getVRQualifiers());
1472}
1473
1474LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1475  bool isNonGC = false;
1476  Expr *BaseExpr = E->getBase();
1477  llvm::Value *BaseValue = NULL;
1478  Qualifiers BaseQuals;
1479
1480  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1481  if (E->isArrow()) {
1482    BaseValue = EmitScalarExpr(BaseExpr);
1483    const PointerType *PTy =
1484      BaseExpr->getType()->getAs<PointerType>();
1485    BaseQuals = PTy->getPointeeType().getQualifiers();
1486  } else if (isa<ObjCPropertyRefExpr>(BaseExpr->IgnoreParens()) ||
1487             isa<ObjCImplicitSetterGetterRefExpr>(
1488               BaseExpr->IgnoreParens())) {
1489    RValue RV = EmitObjCPropertyGet(BaseExpr);
1490    BaseValue = RV.getAggregateAddr();
1491    BaseQuals = BaseExpr->getType().getQualifiers();
1492  } else {
1493    LValue BaseLV = EmitLValue(BaseExpr);
1494    if (BaseLV.isNonGC())
1495      isNonGC = true;
1496    // FIXME: this isn't right for bitfields.
1497    BaseValue = BaseLV.getAddress();
1498    QualType BaseTy = BaseExpr->getType();
1499    BaseQuals = BaseTy.getQualifiers();
1500  }
1501
1502  NamedDecl *ND = E->getMemberDecl();
1503  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1504    LValue LV = EmitLValueForField(BaseValue, Field,
1505                                   BaseQuals.getCVRQualifiers());
1506    LValue::SetObjCNonGC(LV, isNonGC);
1507    setObjCGCLValueClass(getContext(), E, LV);
1508    return LV;
1509  }
1510
1511  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1512    return EmitGlobalVarDeclLValue(*this, E, VD);
1513
1514  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1515    return EmitFunctionDeclLValue(*this, E, FD);
1516
1517  assert(false && "Unhandled member declaration!");
1518  return LValue();
1519}
1520
1521LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value* BaseValue,
1522                                              const FieldDecl* Field,
1523                                              unsigned CVRQualifiers) {
1524  const CGRecordLayout &RL =
1525    CGM.getTypes().getCGRecordLayout(Field->getParent());
1526  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1527  return LValue::MakeBitfield(BaseValue, Info,
1528                             Field->getType().getCVRQualifiers()|CVRQualifiers);
1529}
1530
1531LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
1532                                           const FieldDecl* Field,
1533                                           unsigned CVRQualifiers) {
1534  if (Field->isBitField())
1535    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1536
1537  const CGRecordLayout &RL =
1538    CGM.getTypes().getCGRecordLayout(Field->getParent());
1539  unsigned idx = RL.getLLVMFieldNo(Field);
1540  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1541
1542  // Match union field type.
1543  if (Field->getParent()->isUnion()) {
1544    const llvm::Type *FieldTy =
1545      CGM.getTypes().ConvertTypeForMem(Field->getType());
1546    const llvm::PointerType * BaseTy =
1547      cast<llvm::PointerType>(BaseValue->getType());
1548    unsigned AS = BaseTy->getAddressSpace();
1549    V = Builder.CreateBitCast(V,
1550                              llvm::PointerType::get(FieldTy, AS),
1551                              "tmp");
1552  }
1553  if (Field->getType()->isReferenceType())
1554    V = Builder.CreateLoad(V, "tmp");
1555
1556  Qualifiers Quals = MakeQualifiers(Field->getType());
1557  Quals.addCVRQualifiers(CVRQualifiers);
1558  // __weak attribute on a field is ignored.
1559  if (Quals.getObjCGCAttr() == Qualifiers::Weak)
1560    Quals.removeObjCGCAttr();
1561
1562  return LValue::MakeAddr(V, Quals);
1563}
1564
1565LValue
1566CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value* BaseValue,
1567                                                  const FieldDecl* Field,
1568                                                  unsigned CVRQualifiers) {
1569  QualType FieldType = Field->getType();
1570
1571  if (!FieldType->isReferenceType())
1572    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1573
1574  const CGRecordLayout &RL =
1575    CGM.getTypes().getCGRecordLayout(Field->getParent());
1576  unsigned idx = RL.getLLVMFieldNo(Field);
1577  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1578
1579  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1580
1581  return LValue::MakeAddr(V, MakeQualifiers(FieldType));
1582}
1583
1584LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E){
1585  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1586  const Expr* InitExpr = E->getInitializer();
1587  LValue Result = LValue::MakeAddr(DeclPtr, MakeQualifiers(E->getType()));
1588
1589  EmitAnyExprToMem(InitExpr, DeclPtr, /*Volatile*/ false);
1590
1591  return Result;
1592}
1593
1594LValue
1595CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator* E) {
1596  if (E->isLvalue(getContext()) == Expr::LV_Valid) {
1597    if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1598      Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1599      if (Live)
1600        return EmitLValue(Live);
1601    }
1602
1603    if (!E->getLHS())
1604      return EmitUnsupportedLValue(E, "conditional operator with missing LHS");
1605
1606    llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1607    llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1608    llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1609
1610    EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1611
1612    // Any temporaries created here are conditional.
1613    BeginConditionalBranch();
1614    EmitBlock(LHSBlock);
1615    LValue LHS = EmitLValue(E->getLHS());
1616    EndConditionalBranch();
1617
1618    if (!LHS.isSimple())
1619      return EmitUnsupportedLValue(E, "conditional operator");
1620
1621    // FIXME: We shouldn't need an alloca for this.
1622    llvm::Value *Temp = CreateTempAlloca(LHS.getAddress()->getType(),"condtmp");
1623    Builder.CreateStore(LHS.getAddress(), Temp);
1624    EmitBranch(ContBlock);
1625
1626    // Any temporaries created here are conditional.
1627    BeginConditionalBranch();
1628    EmitBlock(RHSBlock);
1629    LValue RHS = EmitLValue(E->getRHS());
1630    EndConditionalBranch();
1631    if (!RHS.isSimple())
1632      return EmitUnsupportedLValue(E, "conditional operator");
1633
1634    Builder.CreateStore(RHS.getAddress(), Temp);
1635    EmitBranch(ContBlock);
1636
1637    EmitBlock(ContBlock);
1638
1639    Temp = Builder.CreateLoad(Temp, "lv");
1640    return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1641  }
1642
1643  // ?: here should be an aggregate.
1644  assert((hasAggregateLLVMType(E->getType()) &&
1645          !E->getType()->isAnyComplexType()) &&
1646         "Unexpected conditional operator!");
1647
1648  return EmitAggExprToLValue(E);
1649}
1650
1651/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1652/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1653/// otherwise if a cast is needed by the code generator in an lvalue context,
1654/// then it must mean that we need the address of an aggregate in order to
1655/// access one of its fields.  This can happen for all the reasons that casts
1656/// are permitted with aggregate result, including noop aggregate casts, and
1657/// cast from scalar to union.
1658LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1659  switch (E->getCastKind()) {
1660  default:
1661    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1662
1663  case CastExpr::CK_Dynamic: {
1664    LValue LV = EmitLValue(E->getSubExpr());
1665    llvm::Value *V = LV.getAddress();
1666    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1667    return LValue::MakeAddr(EmitDynamicCast(V, DCE),
1668                            MakeQualifiers(E->getType()));
1669  }
1670
1671  case CastExpr::CK_NoOp:
1672  case CastExpr::CK_ConstructorConversion:
1673  case CastExpr::CK_UserDefinedConversion:
1674  case CastExpr::CK_AnyPointerToObjCPointerCast:
1675    return EmitLValue(E->getSubExpr());
1676
1677  case CastExpr::CK_UncheckedDerivedToBase:
1678  case CastExpr::CK_DerivedToBase: {
1679    const RecordType *DerivedClassTy =
1680      E->getSubExpr()->getType()->getAs<RecordType>();
1681    CXXRecordDecl *DerivedClassDecl =
1682      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1683
1684    LValue LV = EmitLValue(E->getSubExpr());
1685
1686    // Perform the derived-to-base conversion
1687    llvm::Value *Base =
1688      GetAddressOfBaseClass(LV.getAddress(), DerivedClassDecl,
1689                            E->getBasePath(), /*NullCheckValue=*/false);
1690
1691    return LValue::MakeAddr(Base, MakeQualifiers(E->getType()));
1692  }
1693  case CastExpr::CK_ToUnion:
1694    return EmitAggExprToLValue(E);
1695  case CastExpr::CK_BaseToDerived: {
1696    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1697    CXXRecordDecl *DerivedClassDecl =
1698      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1699
1700    LValue LV = EmitLValue(E->getSubExpr());
1701
1702    // Perform the base-to-derived conversion
1703    llvm::Value *Derived =
1704      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
1705                               E->getBasePath(),/*NullCheckValue=*/false);
1706
1707    return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
1708  }
1709  case CastExpr::CK_BitCast: {
1710    // This must be a reinterpret_cast (or c-style equivalent).
1711    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1712
1713    LValue LV = EmitLValue(E->getSubExpr());
1714    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1715                                           ConvertType(CE->getTypeAsWritten()));
1716    return LValue::MakeAddr(V, MakeQualifiers(E->getType()));
1717  }
1718  }
1719}
1720
1721LValue CodeGenFunction::EmitNullInitializationLValue(
1722                                              const CXXZeroInitValueExpr *E) {
1723  QualType Ty = E->getType();
1724  LValue LV = LValue::MakeAddr(CreateMemTemp(Ty), MakeQualifiers(Ty));
1725  EmitMemSetToZero(LV.getAddress(), Ty);
1726  return LV;
1727}
1728
1729//===--------------------------------------------------------------------===//
1730//                             Expression Emission
1731//===--------------------------------------------------------------------===//
1732
1733
1734RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1735                                     ReturnValueSlot ReturnValue) {
1736  // Builtins never have block type.
1737  if (E->getCallee()->getType()->isBlockPointerType())
1738    return EmitBlockCallExpr(E, ReturnValue);
1739
1740  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1741    return EmitCXXMemberCallExpr(CE, ReturnValue);
1742
1743  const Decl *TargetDecl = 0;
1744  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1745    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1746      TargetDecl = DRE->getDecl();
1747      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1748        if (unsigned builtinID = FD->getBuiltinID())
1749          return EmitBuiltinExpr(FD, builtinID, E);
1750    }
1751  }
1752
1753  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1754    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1755      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1756
1757  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1758    // C++ [expr.pseudo]p1:
1759    //   The result shall only be used as the operand for the function call
1760    //   operator (), and the result of such a call has type void. The only
1761    //   effect is the evaluation of the postfix-expression before the dot or
1762    //   arrow.
1763    EmitScalarExpr(E->getCallee());
1764    return RValue::get(0);
1765  }
1766
1767  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1768  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1769                  E->arg_begin(), E->arg_end(), TargetDecl);
1770}
1771
1772LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1773  // Comma expressions just emit their LHS then their RHS as an l-value.
1774  if (E->getOpcode() == BinaryOperator::Comma) {
1775    EmitAnyExpr(E->getLHS());
1776    EnsureInsertPoint();
1777    return EmitLValue(E->getRHS());
1778  }
1779
1780  if (E->getOpcode() == BinaryOperator::PtrMemD ||
1781      E->getOpcode() == BinaryOperator::PtrMemI)
1782    return EmitPointerToDataMemberBinaryExpr(E);
1783
1784  // Can only get l-value for binary operator expressions which are a
1785  // simple assignment of aggregate type.
1786  if (E->getOpcode() != BinaryOperator::Assign)
1787    return EmitUnsupportedLValue(E, "binary l-value expression");
1788
1789  if (!hasAggregateLLVMType(E->getType())) {
1790    // Emit the LHS as an l-value.
1791    LValue LV = EmitLValue(E->getLHS());
1792
1793    llvm::Value *RHS = EmitScalarExpr(E->getRHS());
1794    EmitStoreOfScalar(RHS, LV.getAddress(), LV.isVolatileQualified(),
1795                      E->getType());
1796    return LV;
1797  }
1798
1799  return EmitAggExprToLValue(E);
1800}
1801
1802LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1803  RValue RV = EmitCallExpr(E);
1804
1805  if (!RV.isScalar())
1806    return LValue::MakeAddr(RV.getAggregateAddr(),MakeQualifiers(E->getType()));
1807
1808  assert(E->getCallReturnType()->isReferenceType() &&
1809         "Can't have a scalar return unless the return type is a "
1810         "reference type!");
1811
1812  return LValue::MakeAddr(RV.getScalarVal(), MakeQualifiers(E->getType()));
1813}
1814
1815LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1816  // FIXME: This shouldn't require another copy.
1817  return EmitAggExprToLValue(E);
1818}
1819
1820LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1821  llvm::Value *Temp = CreateMemTemp(E->getType(), "tmp");
1822  EmitCXXConstructExpr(Temp, E);
1823  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1824}
1825
1826LValue
1827CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1828  llvm::Value *Temp = EmitCXXTypeidExpr(E);
1829  return LValue::MakeAddr(Temp, MakeQualifiers(E->getType()));
1830}
1831
1832LValue
1833CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
1834  LValue LV = EmitLValue(E->getSubExpr());
1835  PushCXXTemporary(E->getTemporary(), LV.getAddress());
1836  return LV;
1837}
1838
1839LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
1840  // Can only get l-value for message expression returning aggregate type
1841  RValue RV = EmitObjCMessageExpr(E);
1842  // FIXME: can this be volatile?
1843  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1844}
1845
1846llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
1847                                             const ObjCIvarDecl *Ivar) {
1848  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
1849}
1850
1851LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
1852                                          llvm::Value *BaseValue,
1853                                          const ObjCIvarDecl *Ivar,
1854                                          unsigned CVRQualifiers) {
1855  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
1856                                                   Ivar, CVRQualifiers);
1857}
1858
1859LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
1860  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
1861  llvm::Value *BaseValue = 0;
1862  const Expr *BaseExpr = E->getBase();
1863  Qualifiers BaseQuals;
1864  QualType ObjectTy;
1865  if (E->isArrow()) {
1866    BaseValue = EmitScalarExpr(BaseExpr);
1867    ObjectTy = BaseExpr->getType()->getPointeeType();
1868    BaseQuals = ObjectTy.getQualifiers();
1869  } else {
1870    LValue BaseLV = EmitLValue(BaseExpr);
1871    // FIXME: this isn't right for bitfields.
1872    BaseValue = BaseLV.getAddress();
1873    ObjectTy = BaseExpr->getType();
1874    BaseQuals = ObjectTy.getQualifiers();
1875  }
1876
1877  LValue LV =
1878    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
1879                      BaseQuals.getCVRQualifiers());
1880  setObjCGCLValueClass(getContext(), E, LV);
1881  return LV;
1882}
1883
1884LValue
1885CodeGenFunction::EmitObjCPropertyRefLValue(const ObjCPropertyRefExpr *E) {
1886  // This is a special l-value that just issues sends when we load or store
1887  // through it.
1888  return LValue::MakePropertyRef(E, E->getType().getCVRQualifiers());
1889}
1890
1891LValue CodeGenFunction::EmitObjCKVCRefLValue(
1892                                const ObjCImplicitSetterGetterRefExpr *E) {
1893  // This is a special l-value that just issues sends when we load or store
1894  // through it.
1895  return LValue::MakeKVCRef(E, E->getType().getCVRQualifiers());
1896}
1897
1898LValue CodeGenFunction::EmitObjCSuperExprLValue(const ObjCSuperExpr *E) {
1899  return EmitUnsupportedLValue(E, "use of super");
1900}
1901
1902LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
1903  // Can only get l-value for message expression returning aggregate type
1904  RValue RV = EmitAnyExprToTemp(E);
1905  return LValue::MakeAddr(RV.getAggregateAddr(), MakeQualifiers(E->getType()));
1906}
1907
1908RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
1909                                 ReturnValueSlot ReturnValue,
1910                                 CallExpr::const_arg_iterator ArgBeg,
1911                                 CallExpr::const_arg_iterator ArgEnd,
1912                                 const Decl *TargetDecl) {
1913  // Get the actual function type. The callee type will always be a pointer to
1914  // function type or a block pointer type.
1915  assert(CalleeType->isFunctionPointerType() &&
1916         "Call must have function pointer type!");
1917
1918  CalleeType = getContext().getCanonicalType(CalleeType);
1919
1920  const FunctionType *FnType
1921    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
1922  QualType ResultType = FnType->getResultType();
1923
1924  CallArgList Args;
1925  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
1926
1927  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
1928                  Callee, ReturnValue, Args, TargetDecl);
1929}
1930
1931LValue CodeGenFunction::
1932EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
1933  llvm::Value *BaseV;
1934  if (E->getOpcode() == BinaryOperator::PtrMemI)
1935    BaseV = EmitScalarExpr(E->getLHS());
1936  else
1937    BaseV = EmitLValue(E->getLHS()).getAddress();
1938  const llvm::Type *i8Ty = llvm::Type::getInt8PtrTy(getLLVMContext());
1939  BaseV = Builder.CreateBitCast(BaseV, i8Ty);
1940  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
1941  llvm::Value *AddV = Builder.CreateInBoundsGEP(BaseV, OffsetV, "add.ptr");
1942
1943  QualType Ty = E->getRHS()->getType();
1944  Ty = Ty->getAs<MemberPointerType>()->getPointeeType();
1945
1946  const llvm::Type *PType = ConvertType(getContext().getPointerType(Ty));
1947  AddV = Builder.CreateBitCast(AddV, PType);
1948  return LValue::MakeAddr(AddV, MakeQualifiers(Ty));
1949}
1950
1951