CGExpr.cpp revision e996ffd240f20a1048179d7727a6ee3227261921 
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 "CGCXXABI.h"
18#include "CGRecordLayout.h"
19#include "CGObjCRuntime.h"
20#include "clang/AST/ASTContext.h"
21#include "clang/AST/DeclObjC.h"
22#include "llvm/Intrinsics.h"
23#include "clang/Frontend/CodeGenOptions.h"
24#include "llvm/Target/TargetData.h"
25using namespace clang;
26using namespace CodeGen;
27
28//===--------------------------------------------------------------------===//
29//                        Miscellaneous Helper Methods
30//===--------------------------------------------------------------------===//
31
32llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
33  unsigned addressSpace =
34    cast<llvm::PointerType>(value->getType())->getAddressSpace();
35
36  const llvm::PointerType *destType = Int8PtrTy;
37  if (addressSpace)
38    destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
39
40  if (value->getType() == destType) return value;
41  return Builder.CreateBitCast(value, destType);
42}
43
44/// CreateTempAlloca - This creates a alloca and inserts it into the entry
45/// block.
46llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
47                                                    const llvm::Twine &Name) {
48  if (!Builder.isNamePreserving())
49    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
50  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
51}
52
53void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
54                                     llvm::Value *Init) {
55  llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
56  llvm::BasicBlock *Block = AllocaInsertPt->getParent();
57  Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
58}
59
60llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
61                                                const llvm::Twine &Name) {
62  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
63  // FIXME: Should we prefer the preferred type alignment here?
64  CharUnits Align = getContext().getTypeAlignInChars(Ty);
65  Alloc->setAlignment(Align.getQuantity());
66  return Alloc;
67}
68
69llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
70                                                 const llvm::Twine &Name) {
71  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
72  // FIXME: Should we prefer the preferred type alignment here?
73  CharUnits Align = getContext().getTypeAlignInChars(Ty);
74  Alloc->setAlignment(Align.getQuantity());
75  return Alloc;
76}
77
78/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
79/// expression and compare the result against zero, returning an Int1Ty value.
80llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
81  if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
82    llvm::Value *MemPtr = EmitScalarExpr(E);
83    return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT);
84  }
85
86  QualType BoolTy = getContext().BoolTy;
87  if (!E->getType()->isAnyComplexType())
88    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
89
90  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
91}
92
93/// EmitIgnoredExpr - Emit code to compute the specified expression,
94/// ignoring the result.
95void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
96  if (E->isRValue())
97    return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
98
99  // Just emit it as an l-value and drop the result.
100  EmitLValue(E);
101}
102
103/// EmitAnyExpr - Emit code to compute the specified expression which
104/// can have any type.  The result is returned as an RValue struct.
105/// If this is an aggregate expression, AggSlot indicates where the
106/// result should be returned.
107RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot AggSlot,
108                                    bool IgnoreResult) {
109  if (!hasAggregateLLVMType(E->getType()))
110    return RValue::get(EmitScalarExpr(E, IgnoreResult));
111  else if (E->getType()->isAnyComplexType())
112    return RValue::getComplex(EmitComplexExpr(E, IgnoreResult, IgnoreResult));
113
114  EmitAggExpr(E, AggSlot, IgnoreResult);
115  return AggSlot.asRValue();
116}
117
118/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
119/// always be accessible even if no aggregate location is provided.
120RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
121  AggValueSlot AggSlot = AggValueSlot::ignored();
122
123  if (hasAggregateLLVMType(E->getType()) &&
124      !E->getType()->isAnyComplexType())
125    AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
126  return EmitAnyExpr(E, AggSlot);
127}
128
129/// EmitAnyExprToMem - Evaluate an expression into a given memory
130/// location.
131void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
132                                       llvm::Value *Location,
133                                       bool IsLocationVolatile,
134                                       bool IsInit) {
135  if (E->getType()->isComplexType())
136    EmitComplexExprIntoAddr(E, Location, IsLocationVolatile);
137  else if (hasAggregateLLVMType(E->getType()))
138    EmitAggExpr(E, AggValueSlot::forAddr(Location, IsLocationVolatile, IsInit));
139  else {
140    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
141    LValue LV = MakeAddrLValue(Location, E->getType());
142    EmitStoreThroughLValue(RV, LV, E->getType());
143  }
144}
145
146namespace {
147/// \brief An adjustment to be made to the temporary created when emitting a
148/// reference binding, which accesses a particular subobject of that temporary.
149  struct SubobjectAdjustment {
150    enum { DerivedToBaseAdjustment, FieldAdjustment } Kind;
151
152    union {
153      struct {
154        const CastExpr *BasePath;
155        const CXXRecordDecl *DerivedClass;
156      } DerivedToBase;
157
158      FieldDecl *Field;
159    };
160
161    SubobjectAdjustment(const CastExpr *BasePath,
162                        const CXXRecordDecl *DerivedClass)
163      : Kind(DerivedToBaseAdjustment) {
164      DerivedToBase.BasePath = BasePath;
165      DerivedToBase.DerivedClass = DerivedClass;
166    }
167
168    SubobjectAdjustment(FieldDecl *Field)
169      : Kind(FieldAdjustment) {
170      this->Field = Field;
171    }
172  };
173}
174
175static llvm::Value *
176CreateReferenceTemporary(CodeGenFunction& CGF, QualType Type,
177                         const NamedDecl *InitializedDecl) {
178  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
179    if (VD->hasGlobalStorage()) {
180      llvm::SmallString<256> Name;
181      llvm::raw_svector_ostream Out(Name);
182      CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Out);
183      Out.flush();
184
185      const llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
186
187      // Create the reference temporary.
188      llvm::GlobalValue *RefTemp =
189        new llvm::GlobalVariable(CGF.CGM.getModule(),
190                                 RefTempTy, /*isConstant=*/false,
191                                 llvm::GlobalValue::InternalLinkage,
192                                 llvm::Constant::getNullValue(RefTempTy),
193                                 Name.str());
194      return RefTemp;
195    }
196  }
197
198  return CGF.CreateMemTemp(Type, "ref.tmp");
199}
200
201static llvm::Value *
202EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
203                            llvm::Value *&ReferenceTemporary,
204                            const CXXDestructorDecl *&ReferenceTemporaryDtor,
205                            const NamedDecl *InitializedDecl) {
206  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
207    E = DAE->getExpr();
208
209  if (const ExprWithCleanups *TE = dyn_cast<ExprWithCleanups>(E)) {
210    CodeGenFunction::RunCleanupsScope Scope(CGF);
211
212    return EmitExprForReferenceBinding(CGF, TE->getSubExpr(),
213                                       ReferenceTemporary,
214                                       ReferenceTemporaryDtor,
215                                       InitializedDecl);
216  }
217
218  RValue RV;
219  if (E->isGLValue()) {
220    // Emit the expression as an lvalue.
221    LValue LV = CGF.EmitLValue(E);
222    if (LV.isSimple())
223      return LV.getAddress();
224
225    // We have to load the lvalue.
226    RV = CGF.EmitLoadOfLValue(LV, E->getType());
227  } else {
228    QualType ResultTy = E->getType();
229
230    llvm::SmallVector<SubobjectAdjustment, 2> Adjustments;
231    while (true) {
232      if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
233        E = PE->getSubExpr();
234        continue;
235      }
236
237      if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
238        if ((CE->getCastKind() == CK_DerivedToBase ||
239             CE->getCastKind() == CK_UncheckedDerivedToBase) &&
240            E->getType()->isRecordType()) {
241          E = CE->getSubExpr();
242          CXXRecordDecl *Derived
243            = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
244          Adjustments.push_back(SubobjectAdjustment(CE, Derived));
245          continue;
246        }
247
248        if (CE->getCastKind() == CK_NoOp) {
249          E = CE->getSubExpr();
250          continue;
251        }
252      } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
253        if (!ME->isArrow() && ME->getBase()->isRValue()) {
254          assert(ME->getBase()->getType()->isRecordType());
255          if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
256            E = ME->getBase();
257            Adjustments.push_back(SubobjectAdjustment(Field));
258            continue;
259          }
260        }
261      }
262
263      // Nothing changed.
264      break;
265    }
266
267    // Create a reference temporary if necessary.
268    AggValueSlot AggSlot = AggValueSlot::ignored();
269    if (CGF.hasAggregateLLVMType(E->getType()) &&
270        !E->getType()->isAnyComplexType()) {
271      ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
272                                                    InitializedDecl);
273      AggSlot = AggValueSlot::forAddr(ReferenceTemporary, false,
274                                      InitializedDecl != 0);
275    }
276
277    RV = CGF.EmitAnyExpr(E, AggSlot);
278
279    if (InitializedDecl) {
280      // Get the destructor for the reference temporary.
281      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
282        CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
283        if (!ClassDecl->hasTrivialDestructor())
284          ReferenceTemporaryDtor = ClassDecl->getDestructor();
285      }
286    }
287
288    // Check if need to perform derived-to-base casts and/or field accesses, to
289    // get from the temporary object we created (and, potentially, for which we
290    // extended the lifetime) to the subobject we're binding the reference to.
291    if (!Adjustments.empty()) {
292      llvm::Value *Object = RV.getAggregateAddr();
293      for (unsigned I = Adjustments.size(); I != 0; --I) {
294        SubobjectAdjustment &Adjustment = Adjustments[I-1];
295        switch (Adjustment.Kind) {
296        case SubobjectAdjustment::DerivedToBaseAdjustment:
297          Object =
298              CGF.GetAddressOfBaseClass(Object,
299                                        Adjustment.DerivedToBase.DerivedClass,
300                              Adjustment.DerivedToBase.BasePath->path_begin(),
301                              Adjustment.DerivedToBase.BasePath->path_end(),
302                                        /*NullCheckValue=*/false);
303          break;
304
305        case SubobjectAdjustment::FieldAdjustment: {
306          LValue LV =
307            CGF.EmitLValueForField(Object, Adjustment.Field, 0);
308          if (LV.isSimple()) {
309            Object = LV.getAddress();
310            break;
311          }
312
313          // For non-simple lvalues, we actually have to create a copy of
314          // the object we're binding to.
315          QualType T = Adjustment.Field->getType().getNonReferenceType()
316                                                  .getUnqualifiedType();
317          Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
318          LValue TempLV = CGF.MakeAddrLValue(Object,
319                                             Adjustment.Field->getType());
320          CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV, T), TempLV, T);
321          break;
322        }
323
324        }
325      }
326
327      const llvm::Type *ResultPtrTy = CGF.ConvertType(ResultTy)->getPointerTo();
328      return CGF.Builder.CreateBitCast(Object, ResultPtrTy, "temp");
329    }
330  }
331
332  if (RV.isAggregate())
333    return RV.getAggregateAddr();
334
335  // Create a temporary variable that we can bind the reference to.
336  ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
337                                                InitializedDecl);
338
339
340  unsigned Alignment =
341    CGF.getContext().getTypeAlignInChars(E->getType()).getQuantity();
342  if (RV.isScalar())
343    CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
344                          /*Volatile=*/false, Alignment, E->getType());
345  else
346    CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
347                           /*Volatile=*/false);
348  return ReferenceTemporary;
349}
350
351RValue
352CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
353                                            const NamedDecl *InitializedDecl) {
354  llvm::Value *ReferenceTemporary = 0;
355  const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
356  llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
357                                                   ReferenceTemporaryDtor,
358                                                   InitializedDecl);
359  if (!ReferenceTemporaryDtor)
360    return RValue::get(Value);
361
362  // Make sure to call the destructor for the reference temporary.
363  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
364    if (VD->hasGlobalStorage()) {
365      llvm::Constant *DtorFn =
366        CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
367      EmitCXXGlobalDtorRegistration(DtorFn,
368                                    cast<llvm::Constant>(ReferenceTemporary));
369
370      return RValue::get(Value);
371    }
372  }
373
374  PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
375
376  return RValue::get(Value);
377}
378
379
380/// getAccessedFieldNo - Given an encoded value and a result number, return the
381/// input field number being accessed.
382unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
383                                             const llvm::Constant *Elts) {
384  if (isa<llvm::ConstantAggregateZero>(Elts))
385    return 0;
386
387  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
388}
389
390void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
391  if (!CatchUndefined)
392    return;
393
394  // This needs to be to the standard address space.
395  Address = Builder.CreateBitCast(Address, Int8PtrTy);
396
397  const llvm::Type *IntPtrT = IntPtrTy;
398  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, &IntPtrT, 1);
399
400  // In time, people may want to control this and use a 1 here.
401  llvm::Value *Arg = Builder.getFalse();
402  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
403  llvm::BasicBlock *Cont = createBasicBlock();
404  llvm::BasicBlock *Check = createBasicBlock();
405  llvm::Value *NegativeOne = llvm::ConstantInt::get(IntPtrTy, -1ULL);
406  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
407
408  EmitBlock(Check);
409  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
410                                        llvm::ConstantInt::get(IntPtrTy, Size)),
411                       Cont, getTrapBB());
412  EmitBlock(Cont);
413}
414
415
416CodeGenFunction::ComplexPairTy CodeGenFunction::
417EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
418                         bool isInc, bool isPre) {
419  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
420                                            LV.isVolatileQualified());
421
422  llvm::Value *NextVal;
423  if (isa<llvm::IntegerType>(InVal.first->getType())) {
424    uint64_t AmountVal = isInc ? 1 : -1;
425    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
426
427    // Add the inc/dec to the real part.
428    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
429  } else {
430    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
431    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
432    if (!isInc)
433      FVal.changeSign();
434    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
435
436    // Add the inc/dec to the real part.
437    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
438  }
439
440  ComplexPairTy IncVal(NextVal, InVal.second);
441
442  // Store the updated result through the lvalue.
443  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
444
445  // If this is a postinc, return the value read from memory, otherwise use the
446  // updated value.
447  return isPre ? IncVal : InVal;
448}
449
450
451//===----------------------------------------------------------------------===//
452//                         LValue Expression Emission
453//===----------------------------------------------------------------------===//
454
455RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
456  if (Ty->isVoidType())
457    return RValue::get(0);
458
459  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
460    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
461    llvm::Value *U = llvm::UndefValue::get(EltTy);
462    return RValue::getComplex(std::make_pair(U, U));
463  }
464
465  // If this is a use of an undefined aggregate type, the aggregate must have an
466  // identifiable address.  Just because the contents of the value are undefined
467  // doesn't mean that the address can't be taken and compared.
468  if (hasAggregateLLVMType(Ty)) {
469    llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
470    return RValue::getAggregate(DestPtr);
471  }
472
473  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
474}
475
476RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
477                                              const char *Name) {
478  ErrorUnsupported(E, Name);
479  return GetUndefRValue(E->getType());
480}
481
482LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
483                                              const char *Name) {
484  ErrorUnsupported(E, Name);
485  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
486  return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
487}
488
489LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
490  LValue LV = EmitLValue(E);
491  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
492    EmitCheck(LV.getAddress(),
493              getContext().getTypeSizeInChars(E->getType()).getQuantity());
494  return LV;
495}
496
497/// EmitLValue - Emit code to compute a designator that specifies the location
498/// of the expression.
499///
500/// This can return one of two things: a simple address or a bitfield reference.
501/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
502/// an LLVM pointer type.
503///
504/// If this returns a bitfield reference, nothing about the pointee type of the
505/// LLVM value is known: For example, it may not be a pointer to an integer.
506///
507/// If this returns a normal address, and if the lvalue's C type is fixed size,
508/// this method guarantees that the returned pointer type will point to an LLVM
509/// type of the same size of the lvalue's type.  If the lvalue has a variable
510/// length type, this is not possible.
511///
512LValue CodeGenFunction::EmitLValue(const Expr *E) {
513  llvm::DenseMap<const Expr *, LValue>::iterator I =
514                                      ConditionalSaveLValueExprs.find(E);
515  if (I != ConditionalSaveLValueExprs.end())
516    return I->second;
517
518  switch (E->getStmtClass()) {
519  default: return EmitUnsupportedLValue(E, "l-value expression");
520
521  case Expr::ObjCSelectorExprClass:
522  return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
523  case Expr::ObjCIsaExprClass:
524    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
525  case Expr::BinaryOperatorClass:
526    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
527  case Expr::CompoundAssignOperatorClass:
528    if (!E->getType()->isAnyComplexType())
529      return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
530    return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
531  case Expr::CallExprClass:
532  case Expr::CXXMemberCallExprClass:
533  case Expr::CXXOperatorCallExprClass:
534    return EmitCallExprLValue(cast<CallExpr>(E));
535  case Expr::VAArgExprClass:
536    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
537  case Expr::DeclRefExprClass:
538    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
539  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
540  case Expr::PredefinedExprClass:
541    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
542  case Expr::StringLiteralClass:
543    return EmitStringLiteralLValue(cast<StringLiteral>(E));
544  case Expr::ObjCEncodeExprClass:
545    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
546
547  case Expr::BlockDeclRefExprClass:
548    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
549
550  case Expr::CXXTemporaryObjectExprClass:
551  case Expr::CXXConstructExprClass:
552    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
553  case Expr::CXXBindTemporaryExprClass:
554    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
555  case Expr::ExprWithCleanupsClass:
556    return EmitExprWithCleanupsLValue(cast<ExprWithCleanups>(E));
557  case Expr::CXXScalarValueInitExprClass:
558    return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
559  case Expr::CXXDefaultArgExprClass:
560    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
561  case Expr::CXXTypeidExprClass:
562    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
563
564  case Expr::ObjCMessageExprClass:
565    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
566  case Expr::ObjCIvarRefExprClass:
567    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
568  case Expr::ObjCPropertyRefExprClass:
569    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
570  case Expr::StmtExprClass:
571    return EmitStmtExprLValue(cast<StmtExpr>(E));
572  case Expr::UnaryOperatorClass:
573    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
574  case Expr::ArraySubscriptExprClass:
575    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
576  case Expr::ExtVectorElementExprClass:
577    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
578  case Expr::MemberExprClass:
579    return EmitMemberExpr(cast<MemberExpr>(E));
580  case Expr::CompoundLiteralExprClass:
581    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
582  case Expr::ConditionalOperatorClass:
583    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
584  case Expr::ChooseExprClass:
585    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
586  case Expr::OpaqueValueExprClass:
587    return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
588  case Expr::ImplicitCastExprClass:
589  case Expr::CStyleCastExprClass:
590  case Expr::CXXFunctionalCastExprClass:
591  case Expr::CXXStaticCastExprClass:
592  case Expr::CXXDynamicCastExprClass:
593  case Expr::CXXReinterpretCastExprClass:
594  case Expr::CXXConstCastExprClass:
595    return EmitCastLValue(cast<CastExpr>(E));
596  }
597}
598
599llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
600                                              unsigned Alignment, QualType Ty,
601                                              llvm::MDNode *TBAAInfo) {
602  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
603  if (Volatile)
604    Load->setVolatile(true);
605  if (Alignment)
606    Load->setAlignment(Alignment);
607  if (TBAAInfo)
608    CGM.DecorateInstruction(Load, TBAAInfo);
609
610  return EmitFromMemory(Load, Ty);
611}
612
613static bool isBooleanUnderlyingType(QualType Ty) {
614  if (const EnumType *ET = dyn_cast<EnumType>(Ty))
615    return ET->getDecl()->getIntegerType()->isBooleanType();
616  return false;
617}
618
619llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
620  // Bool has a different representation in memory than in registers.
621  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
622    // This should really always be an i1, but sometimes it's already
623    // an i8, and it's awkward to track those cases down.
624    if (Value->getType()->isIntegerTy(1))
625      return Builder.CreateZExt(Value, Builder.getInt8Ty(), "frombool");
626    assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
627  }
628
629  return Value;
630}
631
632llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
633  // Bool has a different representation in memory than in registers.
634  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
635    assert(Value->getType()->isIntegerTy(8) && "memory rep of bool not i8");
636    return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
637  }
638
639  return Value;
640}
641
642void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
643                                        bool Volatile, unsigned Alignment,
644                                        QualType Ty,
645                                        llvm::MDNode *TBAAInfo) {
646  Value = EmitToMemory(Value, Ty);
647  llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
648  if (Alignment)
649    Store->setAlignment(Alignment);
650  if (TBAAInfo)
651    CGM.DecorateInstruction(Store, TBAAInfo);
652}
653
654/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
655/// method emits the address of the lvalue, then loads the result as an rvalue,
656/// returning the rvalue.
657RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
658  if (LV.isObjCWeak()) {
659    // load of a __weak object.
660    llvm::Value *AddrWeakObj = LV.getAddress();
661    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
662                                                             AddrWeakObj));
663  }
664
665  if (LV.isSimple()) {
666    llvm::Value *Ptr = LV.getAddress();
667
668    // Functions are l-values that don't require loading.
669    if (ExprType->isFunctionType())
670      return RValue::get(Ptr);
671
672    // Everything needs a load.
673    return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
674                                        LV.getAlignment(), ExprType,
675                                        LV.getTBAAInfo()));
676
677  }
678
679  if (LV.isVectorElt()) {
680    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
681                                          LV.isVolatileQualified(), "tmp");
682    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
683                                                    "vecext"));
684  }
685
686  // If this is a reference to a subset of the elements of a vector, either
687  // shuffle the input or extract/insert them as appropriate.
688  if (LV.isExtVectorElt())
689    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
690
691  if (LV.isBitField())
692    return EmitLoadOfBitfieldLValue(LV, ExprType);
693
694  assert(LV.isPropertyRef() && "Unknown LValue type!");
695  return EmitLoadOfPropertyRefLValue(LV);
696}
697
698RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
699                                                 QualType ExprType) {
700  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
701
702  // Get the output type.
703  const llvm::Type *ResLTy = ConvertType(ExprType);
704  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
705
706  // Compute the result as an OR of all of the individual component accesses.
707  llvm::Value *Res = 0;
708  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
709    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
710
711    // Get the field pointer.
712    llvm::Value *Ptr = LV.getBitFieldBaseAddr();
713
714    // Only offset by the field index if used, so that incoming values are not
715    // required to be structures.
716    if (AI.FieldIndex)
717      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
718
719    // Offset by the byte offset, if used.
720    if (AI.FieldByteOffset) {
721      Ptr = EmitCastToVoidPtr(Ptr);
722      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
723    }
724
725    // Cast to the access type.
726    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(getLLVMContext(),
727                                                     AI.AccessWidth,
728                                                    ExprType.getAddressSpace());
729    Ptr = Builder.CreateBitCast(Ptr, PTy);
730
731    // Perform the load.
732    llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
733    if (AI.AccessAlignment)
734      Load->setAlignment(AI.AccessAlignment);
735
736    // Shift out unused low bits and mask out unused high bits.
737    llvm::Value *Val = Load;
738    if (AI.FieldBitStart)
739      Val = Builder.CreateLShr(Load, AI.FieldBitStart);
740    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
741                                                            AI.TargetBitWidth),
742                            "bf.clear");
743
744    // Extend or truncate to the target size.
745    if (AI.AccessWidth < ResSizeInBits)
746      Val = Builder.CreateZExt(Val, ResLTy);
747    else if (AI.AccessWidth > ResSizeInBits)
748      Val = Builder.CreateTrunc(Val, ResLTy);
749
750    // Shift into place, and OR into the result.
751    if (AI.TargetBitOffset)
752      Val = Builder.CreateShl(Val, AI.TargetBitOffset);
753    Res = Res ? Builder.CreateOr(Res, Val) : Val;
754  }
755
756  // If the bit-field is signed, perform the sign-extension.
757  //
758  // FIXME: This can easily be folded into the load of the high bits, which
759  // could also eliminate the mask of high bits in some situations.
760  if (Info.isSigned()) {
761    unsigned ExtraBits = ResSizeInBits - Info.getSize();
762    if (ExtraBits)
763      Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
764                               ExtraBits, "bf.val.sext");
765  }
766
767  return RValue::get(Res);
768}
769
770// If this is a reference to a subset of the elements of a vector, create an
771// appropriate shufflevector.
772RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
773                                                         QualType ExprType) {
774  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
775                                        LV.isVolatileQualified(), "tmp");
776
777  const llvm::Constant *Elts = LV.getExtVectorElts();
778
779  // If the result of the expression is a non-vector type, we must be extracting
780  // a single element.  Just codegen as an extractelement.
781  const VectorType *ExprVT = ExprType->getAs<VectorType>();
782  if (!ExprVT) {
783    unsigned InIdx = getAccessedFieldNo(0, Elts);
784    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
785    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
786  }
787
788  // Always use shuffle vector to try to retain the original program structure
789  unsigned NumResultElts = ExprVT->getNumElements();
790
791  llvm::SmallVector<llvm::Constant*, 4> Mask;
792  for (unsigned i = 0; i != NumResultElts; ++i) {
793    unsigned InIdx = getAccessedFieldNo(i, Elts);
794    Mask.push_back(llvm::ConstantInt::get(Int32Ty, InIdx));
795  }
796
797  llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
798  Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()),
799                                    MaskV, "tmp");
800  return RValue::get(Vec);
801}
802
803
804
805/// EmitStoreThroughLValue - Store the specified rvalue into the specified
806/// lvalue, where both are guaranteed to the have the same type, and that type
807/// is 'Ty'.
808void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
809                                             QualType Ty) {
810  if (!Dst.isSimple()) {
811    if (Dst.isVectorElt()) {
812      // Read/modify/write the vector, inserting the new element.
813      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
814                                            Dst.isVolatileQualified(), "tmp");
815      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
816                                        Dst.getVectorIdx(), "vecins");
817      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
818      return;
819    }
820
821    // If this is an update of extended vector elements, insert them as
822    // appropriate.
823    if (Dst.isExtVectorElt())
824      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
825
826    if (Dst.isBitField())
827      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
828
829    assert(Dst.isPropertyRef() && "Unknown LValue type");
830    return EmitStoreThroughPropertyRefLValue(Src, Dst);
831  }
832
833  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
834    // load of a __weak object.
835    llvm::Value *LvalueDst = Dst.getAddress();
836    llvm::Value *src = Src.getScalarVal();
837     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
838    return;
839  }
840
841  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
842    // load of a __strong object.
843    llvm::Value *LvalueDst = Dst.getAddress();
844    llvm::Value *src = Src.getScalarVal();
845    if (Dst.isObjCIvar()) {
846      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
847      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
848      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
849      llvm::Value *dst = RHS;
850      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
851      llvm::Value *LHS =
852        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
853      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
854      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
855                                              BytesBetween);
856    } else if (Dst.isGlobalObjCRef()) {
857      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
858                                                Dst.isThreadLocalRef());
859    }
860    else
861      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
862    return;
863  }
864
865  assert(Src.isScalar() && "Can't emit an agg store with this method");
866  EmitStoreOfScalar(Src.getScalarVal(), Dst.getAddress(),
867                    Dst.isVolatileQualified(), Dst.getAlignment(), Ty,
868                    Dst.getTBAAInfo());
869}
870
871void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
872                                                     QualType Ty,
873                                                     llvm::Value **Result) {
874  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
875
876  // Get the output type.
877  const llvm::Type *ResLTy = ConvertTypeForMem(Ty);
878  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
879
880  // Get the source value, truncated to the width of the bit-field.
881  llvm::Value *SrcVal = Src.getScalarVal();
882
883  if (Ty->isBooleanType())
884    SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
885
886  SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
887                                                                Info.getSize()),
888                             "bf.value");
889
890  // Return the new value of the bit-field, if requested.
891  if (Result) {
892    // Cast back to the proper type for result.
893    const llvm::Type *SrcTy = Src.getScalarVal()->getType();
894    llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
895                                                   "bf.reload.val");
896
897    // Sign extend if necessary.
898    if (Info.isSigned()) {
899      unsigned ExtraBits = ResSizeInBits - Info.getSize();
900      if (ExtraBits)
901        ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
902                                       ExtraBits, "bf.reload.sext");
903    }
904
905    *Result = ReloadVal;
906  }
907
908  // Iterate over the components, writing each piece to memory.
909  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
910    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
911
912    // Get the field pointer.
913    llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
914    unsigned addressSpace =
915      cast<llvm::PointerType>(Ptr->getType())->getAddressSpace();
916
917    // Only offset by the field index if used, so that incoming values are not
918    // required to be structures.
919    if (AI.FieldIndex)
920      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
921
922    // Offset by the byte offset, if used.
923    if (AI.FieldByteOffset) {
924      Ptr = EmitCastToVoidPtr(Ptr);
925      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset,"bf.field.offs");
926    }
927
928    // Cast to the access type.
929    const llvm::Type *AccessLTy =
930      llvm::Type::getIntNTy(getLLVMContext(), AI.AccessWidth);
931
932    const llvm::Type *PTy = AccessLTy->getPointerTo(addressSpace);
933    Ptr = Builder.CreateBitCast(Ptr, PTy);
934
935    // Extract the piece of the bit-field value to write in this access, limited
936    // to the values that are part of this access.
937    llvm::Value *Val = SrcVal;
938    if (AI.TargetBitOffset)
939      Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
940    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
941                                                            AI.TargetBitWidth));
942
943    // Extend or truncate to the access size.
944    if (ResSizeInBits < AI.AccessWidth)
945      Val = Builder.CreateZExt(Val, AccessLTy);
946    else if (ResSizeInBits > AI.AccessWidth)
947      Val = Builder.CreateTrunc(Val, AccessLTy);
948
949    // Shift into the position in memory.
950    if (AI.FieldBitStart)
951      Val = Builder.CreateShl(Val, AI.FieldBitStart);
952
953    // If necessary, load and OR in bits that are outside of the bit-field.
954    if (AI.TargetBitWidth != AI.AccessWidth) {
955      llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
956      if (AI.AccessAlignment)
957        Load->setAlignment(AI.AccessAlignment);
958
959      // Compute the mask for zeroing the bits that are part of the bit-field.
960      llvm::APInt InvMask =
961        ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
962                                 AI.FieldBitStart + AI.TargetBitWidth);
963
964      // Apply the mask and OR in to the value to write.
965      Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
966    }
967
968    // Write the value.
969    llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
970                                                 Dst.isVolatileQualified());
971    if (AI.AccessAlignment)
972      Store->setAlignment(AI.AccessAlignment);
973  }
974}
975
976void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
977                                                               LValue Dst,
978                                                               QualType Ty) {
979  // This access turns into a read/modify/write of the vector.  Load the input
980  // value now.
981  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
982                                        Dst.isVolatileQualified(), "tmp");
983  const llvm::Constant *Elts = Dst.getExtVectorElts();
984
985  llvm::Value *SrcVal = Src.getScalarVal();
986
987  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
988    unsigned NumSrcElts = VTy->getNumElements();
989    unsigned NumDstElts =
990       cast<llvm::VectorType>(Vec->getType())->getNumElements();
991    if (NumDstElts == NumSrcElts) {
992      // Use shuffle vector is the src and destination are the same number of
993      // elements and restore the vector mask since it is on the side it will be
994      // stored.
995      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
996      for (unsigned i = 0; i != NumSrcElts; ++i) {
997        unsigned InIdx = getAccessedFieldNo(i, Elts);
998        Mask[InIdx] = llvm::ConstantInt::get(Int32Ty, i);
999      }
1000
1001      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1002      Vec = Builder.CreateShuffleVector(SrcVal,
1003                                        llvm::UndefValue::get(Vec->getType()),
1004                                        MaskV, "tmp");
1005    } else if (NumDstElts > NumSrcElts) {
1006      // Extended the source vector to the same length and then shuffle it
1007      // into the destination.
1008      // FIXME: since we're shuffling with undef, can we just use the indices
1009      //        into that?  This could be simpler.
1010      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
1011      unsigned i;
1012      for (i = 0; i != NumSrcElts; ++i)
1013        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1014      for (; i != NumDstElts; ++i)
1015        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
1016      llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
1017      llvm::Value *ExtSrcVal =
1018        Builder.CreateShuffleVector(SrcVal,
1019                                    llvm::UndefValue::get(SrcVal->getType()),
1020                                    ExtMaskV, "tmp");
1021      // build identity
1022      llvm::SmallVector<llvm::Constant*, 4> Mask;
1023      for (unsigned i = 0; i != NumDstElts; ++i)
1024        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1025
1026      // modify when what gets shuffled in
1027      for (unsigned i = 0; i != NumSrcElts; ++i) {
1028        unsigned Idx = getAccessedFieldNo(i, Elts);
1029        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
1030      }
1031      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1032      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
1033    } else {
1034      // We should never shorten the vector
1035      assert(0 && "unexpected shorten vector length");
1036    }
1037  } else {
1038    // If the Src is a scalar (not a vector) it must be updating one element.
1039    unsigned InIdx = getAccessedFieldNo(0, Elts);
1040    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1041    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
1042  }
1043
1044  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1045}
1046
1047// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1048// generating write-barries API. It is currently a global, ivar,
1049// or neither.
1050static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1051                                 LValue &LV) {
1052  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
1053    return;
1054
1055  if (isa<ObjCIvarRefExpr>(E)) {
1056    LV.setObjCIvar(true);
1057    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1058    LV.setBaseIvarExp(Exp->getBase());
1059    LV.setObjCArray(E->getType()->isArrayType());
1060    return;
1061  }
1062
1063  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1064    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1065      if (VD->hasGlobalStorage()) {
1066        LV.setGlobalObjCRef(true);
1067        LV.setThreadLocalRef(VD->isThreadSpecified());
1068      }
1069    }
1070    LV.setObjCArray(E->getType()->isArrayType());
1071    return;
1072  }
1073
1074  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1075    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1076    return;
1077  }
1078
1079  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1080    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1081    if (LV.isObjCIvar()) {
1082      // If cast is to a structure pointer, follow gcc's behavior and make it
1083      // a non-ivar write-barrier.
1084      QualType ExpTy = E->getType();
1085      if (ExpTy->isPointerType())
1086        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1087      if (ExpTy->isRecordType())
1088        LV.setObjCIvar(false);
1089    }
1090    return;
1091  }
1092  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1093    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1094    return;
1095  }
1096
1097  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1098    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1099    return;
1100  }
1101
1102  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1103    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1104    if (LV.isObjCIvar() && !LV.isObjCArray())
1105      // Using array syntax to assigning to what an ivar points to is not
1106      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1107      LV.setObjCIvar(false);
1108    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1109      // Using array syntax to assigning to what global points to is not
1110      // same as assigning to the global itself. {id *G;} G[i] = 0;
1111      LV.setGlobalObjCRef(false);
1112    return;
1113  }
1114
1115  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1116    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1117    // We don't know if member is an 'ivar', but this flag is looked at
1118    // only in the context of LV.isObjCIvar().
1119    LV.setObjCArray(E->getType()->isArrayType());
1120    return;
1121  }
1122}
1123
1124static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1125                                      const Expr *E, const VarDecl *VD) {
1126  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1127         "Var decl must have external storage or be a file var decl!");
1128
1129  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1130  if (VD->getType()->isReferenceType())
1131    V = CGF.Builder.CreateLoad(V, "tmp");
1132  unsigned Alignment = CGF.getContext().getDeclAlign(VD).getQuantity();
1133  LValue LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1134  setObjCGCLValueClass(CGF.getContext(), E, LV);
1135  return LV;
1136}
1137
1138static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1139                                      const Expr *E, const FunctionDecl *FD) {
1140  llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1141  if (!FD->hasPrototype()) {
1142    if (const FunctionProtoType *Proto =
1143            FD->getType()->getAs<FunctionProtoType>()) {
1144      // Ugly case: for a K&R-style definition, the type of the definition
1145      // isn't the same as the type of a use.  Correct for this with a
1146      // bitcast.
1147      QualType NoProtoType =
1148          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1149      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1150      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1151    }
1152  }
1153  unsigned Alignment = CGF.getContext().getDeclAlign(FD).getQuantity();
1154  return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1155}
1156
1157LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1158  const NamedDecl *ND = E->getDecl();
1159  unsigned Alignment = getContext().getDeclAlign(ND).getQuantity();
1160
1161  if (ND->hasAttr<WeakRefAttr>()) {
1162    const ValueDecl *VD = cast<ValueDecl>(ND);
1163    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1164    return MakeAddrLValue(Aliasee, E->getType(), Alignment);
1165  }
1166
1167  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1168
1169    // Check if this is a global variable.
1170    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1171      return EmitGlobalVarDeclLValue(*this, E, VD);
1172
1173    bool NonGCable = VD->hasLocalStorage() &&
1174                     !VD->getType()->isReferenceType() &&
1175                     !VD->hasAttr<BlocksAttr>();
1176
1177    llvm::Value *V = LocalDeclMap[VD];
1178    if (!V && VD->isStaticLocal())
1179      V = CGM.getStaticLocalDeclAddress(VD);
1180    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1181
1182    if (VD->hasAttr<BlocksAttr>())
1183      V = BuildBlockByrefAddress(V, VD);
1184
1185    if (VD->getType()->isReferenceType())
1186      V = Builder.CreateLoad(V, "tmp");
1187
1188    LValue LV = MakeAddrLValue(V, E->getType(), Alignment);
1189    if (NonGCable) {
1190      LV.getQuals().removeObjCGCAttr();
1191      LV.setNonGC(true);
1192    }
1193    setObjCGCLValueClass(getContext(), E, LV);
1194    return LV;
1195  }
1196
1197  if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
1198    return EmitFunctionDeclLValue(*this, E, fn);
1199
1200  assert(false && "Unhandled DeclRefExpr");
1201
1202  // an invalid LValue, but the assert will
1203  // ensure that this point is never reached.
1204  return LValue();
1205}
1206
1207LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1208  unsigned Alignment =
1209    getContext().getDeclAlign(E->getDecl()).getQuantity();
1210  return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
1211}
1212
1213LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1214  // __extension__ doesn't affect lvalue-ness.
1215  if (E->getOpcode() == UO_Extension)
1216    return EmitLValue(E->getSubExpr());
1217
1218  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1219  switch (E->getOpcode()) {
1220  default: assert(0 && "Unknown unary operator lvalue!");
1221  case UO_Deref: {
1222    QualType T = E->getSubExpr()->getType()->getPointeeType();
1223    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1224
1225    LValue LV = MakeAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1226    LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1227
1228    // We should not generate __weak write barrier on indirect reference
1229    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1230    // But, we continue to generate __strong write barrier on indirect write
1231    // into a pointer to object.
1232    if (getContext().getLangOptions().ObjC1 &&
1233        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1234        LV.isObjCWeak())
1235      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1236    return LV;
1237  }
1238  case UO_Real:
1239  case UO_Imag: {
1240    LValue LV = EmitLValue(E->getSubExpr());
1241    assert(LV.isSimple() && "real/imag on non-ordinary l-value");
1242    llvm::Value *Addr = LV.getAddress();
1243
1244    // real and imag are valid on scalars.  This is a faster way of
1245    // testing that.
1246    if (!cast<llvm::PointerType>(Addr->getType())
1247           ->getElementType()->isStructTy()) {
1248      assert(E->getSubExpr()->getType()->isArithmeticType());
1249      return LV;
1250    }
1251
1252    assert(E->getSubExpr()->getType()->isAnyComplexType());
1253
1254    unsigned Idx = E->getOpcode() == UO_Imag;
1255    return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1256                                                  Idx, "idx"),
1257                          ExprTy);
1258  }
1259  case UO_PreInc:
1260  case UO_PreDec: {
1261    LValue LV = EmitLValue(E->getSubExpr());
1262    bool isInc = E->getOpcode() == UO_PreInc;
1263
1264    if (E->getType()->isAnyComplexType())
1265      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1266    else
1267      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1268    return LV;
1269  }
1270  }
1271}
1272
1273LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1274  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1275                        E->getType());
1276}
1277
1278LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1279  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1280                        E->getType());
1281}
1282
1283
1284LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1285  switch (E->getIdentType()) {
1286  default:
1287    return EmitUnsupportedLValue(E, "predefined expression");
1288
1289  case PredefinedExpr::Func:
1290  case PredefinedExpr::Function:
1291  case PredefinedExpr::PrettyFunction: {
1292    unsigned Type = E->getIdentType();
1293    std::string GlobalVarName;
1294
1295    switch (Type) {
1296    default: assert(0 && "Invalid type");
1297    case PredefinedExpr::Func:
1298      GlobalVarName = "__func__.";
1299      break;
1300    case PredefinedExpr::Function:
1301      GlobalVarName = "__FUNCTION__.";
1302      break;
1303    case PredefinedExpr::PrettyFunction:
1304      GlobalVarName = "__PRETTY_FUNCTION__.";
1305      break;
1306    }
1307
1308    llvm::StringRef FnName = CurFn->getName();
1309    if (FnName.startswith("\01"))
1310      FnName = FnName.substr(1);
1311    GlobalVarName += FnName;
1312
1313    const Decl *CurDecl = CurCodeDecl;
1314    if (CurDecl == 0)
1315      CurDecl = getContext().getTranslationUnitDecl();
1316
1317    std::string FunctionName =
1318        (isa<BlockDecl>(CurDecl)
1319         ? FnName.str()
1320         : PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl));
1321
1322    llvm::Constant *C =
1323      CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1324    return MakeAddrLValue(C, E->getType());
1325  }
1326  }
1327}
1328
1329llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1330  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1331
1332  // If we are not optimzing, don't collapse all calls to trap in the function
1333  // to the same call, that way, in the debugger they can see which operation
1334  // did in fact fail.  If we are optimizing, we collapse all calls to trap down
1335  // to just one per function to save on codesize.
1336  if (GCO.OptimizationLevel && TrapBB)
1337    return TrapBB;
1338
1339  llvm::BasicBlock *Cont = 0;
1340  if (HaveInsertPoint()) {
1341    Cont = createBasicBlock("cont");
1342    EmitBranch(Cont);
1343  }
1344  TrapBB = createBasicBlock("trap");
1345  EmitBlock(TrapBB);
1346
1347  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1348  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1349  TrapCall->setDoesNotReturn();
1350  TrapCall->setDoesNotThrow();
1351  Builder.CreateUnreachable();
1352
1353  if (Cont)
1354    EmitBlock(Cont);
1355  return TrapBB;
1356}
1357
1358/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
1359/// array to pointer, return the array subexpression.
1360static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
1361  // If this isn't just an array->pointer decay, bail out.
1362  const CastExpr *CE = dyn_cast<CastExpr>(E);
1363  if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
1364    return 0;
1365
1366  // If this is a decay from variable width array, bail out.
1367  const Expr *SubExpr = CE->getSubExpr();
1368  if (SubExpr->getType()->isVariableArrayType())
1369    return 0;
1370
1371  return SubExpr;
1372}
1373
1374LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1375  // The index must always be an integer, which is not an aggregate.  Emit it.
1376  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1377  QualType IdxTy  = E->getIdx()->getType();
1378  bool IdxSigned = IdxTy->isSignedIntegerType();
1379
1380  // If the base is a vector type, then we are forming a vector element lvalue
1381  // with this subscript.
1382  if (E->getBase()->getType()->isVectorType()) {
1383    // Emit the vector as an lvalue to get its address.
1384    LValue LHS = EmitLValue(E->getBase());
1385    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1386    Idx = Builder.CreateIntCast(Idx, Int32Ty, IdxSigned, "vidx");
1387    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1388                                 E->getBase()->getType().getCVRQualifiers());
1389  }
1390
1391  // Extend or truncate the index type to 32 or 64-bits.
1392  if (Idx->getType() != IntPtrTy)
1393    Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
1394
1395  // FIXME: As llvm implements the object size checking, this can come out.
1396  if (CatchUndefined) {
1397    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())){
1398      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1399        if (ICE->getCastKind() == CK_ArrayToPointerDecay) {
1400          if (const ConstantArrayType *CAT
1401              = getContext().getAsConstantArrayType(DRE->getType())) {
1402            llvm::APInt Size = CAT->getSize();
1403            llvm::BasicBlock *Cont = createBasicBlock("cont");
1404            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1405                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1406                                 Cont, getTrapBB());
1407            EmitBlock(Cont);
1408          }
1409        }
1410      }
1411    }
1412  }
1413
1414  // We know that the pointer points to a type of the correct size, unless the
1415  // size is a VLA or Objective-C interface.
1416  llvm::Value *Address = 0;
1417  if (const VariableArrayType *VAT =
1418        getContext().getAsVariableArrayType(E->getType())) {
1419    llvm::Value *VLASize = GetVLASize(VAT);
1420
1421    Idx = Builder.CreateMul(Idx, VLASize);
1422
1423    // The base must be a pointer, which is not an aggregate.  Emit it.
1424    llvm::Value *Base = EmitScalarExpr(E->getBase());
1425
1426    Address = EmitCastToVoidPtr(Base);
1427    Address = Builder.CreateInBoundsGEP(Address, Idx, "arrayidx");
1428    Address = Builder.CreateBitCast(Address, Base->getType());
1429  } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
1430    // Indexing over an interface, as in "NSString *P; P[4];"
1431    llvm::Value *InterfaceSize =
1432      llvm::ConstantInt::get(Idx->getType(),
1433          getContext().getTypeSizeInChars(OIT).getQuantity());
1434
1435    Idx = Builder.CreateMul(Idx, InterfaceSize);
1436
1437    // The base must be a pointer, which is not an aggregate.  Emit it.
1438    llvm::Value *Base = EmitScalarExpr(E->getBase());
1439    Address = EmitCastToVoidPtr(Base);
1440    Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1441    Address = Builder.CreateBitCast(Address, Base->getType());
1442  } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
1443    // If this is A[i] where A is an array, the frontend will have decayed the
1444    // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
1445    // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
1446    // "gep x, i" here.  Emit one "gep A, 0, i".
1447    assert(Array->getType()->isArrayType() &&
1448           "Array to pointer decay must have array source type!");
1449    llvm::Value *ArrayPtr = EmitLValue(Array).getAddress();
1450    llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
1451    llvm::Value *Args[] = { Zero, Idx };
1452
1453    Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, Args+2, "arrayidx");
1454  } else {
1455    // The base must be a pointer, which is not an aggregate.  Emit it.
1456    llvm::Value *Base = EmitScalarExpr(E->getBase());
1457    Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1458  }
1459
1460  QualType T = E->getBase()->getType()->getPointeeType();
1461  assert(!T.isNull() &&
1462         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1463
1464  LValue LV = MakeAddrLValue(Address, T);
1465  LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
1466
1467  if (getContext().getLangOptions().ObjC1 &&
1468      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1469    LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1470    setObjCGCLValueClass(getContext(), E, LV);
1471  }
1472  return LV;
1473}
1474
1475static
1476llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1477                                       llvm::SmallVector<unsigned, 4> &Elts) {
1478  llvm::SmallVector<llvm::Constant*, 4> CElts;
1479
1480  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1481  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1482    CElts.push_back(llvm::ConstantInt::get(Int32Ty, Elts[i]));
1483
1484  return llvm::ConstantVector::get(CElts);
1485}
1486
1487LValue CodeGenFunction::
1488EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1489  // Emit the base vector as an l-value.
1490  LValue Base;
1491
1492  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1493  if (E->isArrow()) {
1494    // If it is a pointer to a vector, emit the address and form an lvalue with
1495    // it.
1496    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1497    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1498    Base = MakeAddrLValue(Ptr, PT->getPointeeType());
1499    Base.getQuals().removeObjCGCAttr();
1500  } else if (E->getBase()->isGLValue()) {
1501    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1502    // emit the base as an lvalue.
1503    assert(E->getBase()->getType()->isVectorType());
1504    Base = EmitLValue(E->getBase());
1505  } else {
1506    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1507    assert(E->getBase()->getType()->getAs<VectorType>() &&
1508           "Result must be a vector");
1509    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1510
1511    // Store the vector to memory (because LValue wants an address).
1512    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1513    Builder.CreateStore(Vec, VecMem);
1514    Base = MakeAddrLValue(VecMem, E->getBase()->getType());
1515  }
1516
1517  // Encode the element access list into a vector of unsigned indices.
1518  llvm::SmallVector<unsigned, 4> Indices;
1519  E->getEncodedElementAccess(Indices);
1520
1521  if (Base.isSimple()) {
1522    llvm::Constant *CV = GenerateConstantVector(getLLVMContext(), Indices);
1523    return LValue::MakeExtVectorElt(Base.getAddress(), CV,
1524                                    Base.getVRQualifiers());
1525  }
1526  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1527
1528  llvm::Constant *BaseElts = Base.getExtVectorElts();
1529  llvm::SmallVector<llvm::Constant *, 4> CElts;
1530
1531  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1532    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1533      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1534    else
1535      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1536  }
1537  llvm::Constant *CV = llvm::ConstantVector::get(CElts);
1538  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
1539                                  Base.getVRQualifiers());
1540}
1541
1542LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1543  bool isNonGC = false;
1544  Expr *BaseExpr = E->getBase();
1545  llvm::Value *BaseValue = NULL;
1546  Qualifiers BaseQuals;
1547
1548  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1549  if (E->isArrow()) {
1550    BaseValue = EmitScalarExpr(BaseExpr);
1551    const PointerType *PTy =
1552      BaseExpr->getType()->getAs<PointerType>();
1553    BaseQuals = PTy->getPointeeType().getQualifiers();
1554  } else {
1555    LValue BaseLV = EmitLValue(BaseExpr);
1556    if (BaseLV.isNonGC())
1557      isNonGC = true;
1558    // FIXME: this isn't right for bitfields.
1559    BaseValue = BaseLV.getAddress();
1560    QualType BaseTy = BaseExpr->getType();
1561    BaseQuals = BaseTy.getQualifiers();
1562  }
1563
1564  NamedDecl *ND = E->getMemberDecl();
1565  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1566    LValue LV = EmitLValueForField(BaseValue, Field,
1567                                   BaseQuals.getCVRQualifiers());
1568    LV.setNonGC(isNonGC);
1569    setObjCGCLValueClass(getContext(), E, LV);
1570    return LV;
1571  }
1572
1573  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1574    return EmitGlobalVarDeclLValue(*this, E, VD);
1575
1576  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1577    return EmitFunctionDeclLValue(*this, E, FD);
1578
1579  assert(false && "Unhandled member declaration!");
1580  return LValue();
1581}
1582
1583LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
1584                                              const FieldDecl *Field,
1585                                              unsigned CVRQualifiers) {
1586  const CGRecordLayout &RL =
1587    CGM.getTypes().getCGRecordLayout(Field->getParent());
1588  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1589  return LValue::MakeBitfield(BaseValue, Info,
1590                             Field->getType().getCVRQualifiers()|CVRQualifiers);
1591}
1592
1593/// EmitLValueForAnonRecordField - Given that the field is a member of
1594/// an anonymous struct or union buried inside a record, and given
1595/// that the base value is a pointer to the enclosing record, derive
1596/// an lvalue for the ultimate field.
1597LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
1598                                             const IndirectFieldDecl *Field,
1599                                                     unsigned CVRQualifiers) {
1600  IndirectFieldDecl::chain_iterator I = Field->chain_begin(),
1601    IEnd = Field->chain_end();
1602  while (true) {
1603    LValue LV = EmitLValueForField(BaseValue, cast<FieldDecl>(*I), CVRQualifiers);
1604    if (++I == IEnd) return LV;
1605
1606    assert(LV.isSimple());
1607    BaseValue = LV.getAddress();
1608    CVRQualifiers |= LV.getVRQualifiers();
1609  }
1610}
1611
1612LValue CodeGenFunction::EmitLValueForField(llvm::Value *BaseValue,
1613                                           const FieldDecl *Field,
1614                                           unsigned CVRQualifiers) {
1615  if (Field->isBitField())
1616    return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
1617
1618  const CGRecordLayout &RL =
1619    CGM.getTypes().getCGRecordLayout(Field->getParent());
1620  unsigned idx = RL.getLLVMFieldNo(Field);
1621  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1622
1623  // Match union field type.
1624  if (Field->getParent()->isUnion()) {
1625    const llvm::Type *FieldTy =
1626      CGM.getTypes().ConvertTypeForMem(Field->getType());
1627    const llvm::PointerType *BaseTy =
1628      cast<llvm::PointerType>(BaseValue->getType());
1629    unsigned AS = BaseTy->getAddressSpace();
1630    V = Builder.CreateBitCast(V,
1631                              llvm::PointerType::get(FieldTy, AS),
1632                              "tmp");
1633  }
1634  if (Field->getType()->isReferenceType())
1635    V = Builder.CreateLoad(V, "tmp");
1636
1637  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1638  LValue LV = MakeAddrLValue(V, Field->getType(), Alignment);
1639  LV.getQuals().addCVRQualifiers(CVRQualifiers);
1640
1641  // __weak attribute on a field is ignored.
1642  if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
1643    LV.getQuals().removeObjCGCAttr();
1644
1645  return LV;
1646}
1647
1648LValue
1649CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value *BaseValue,
1650                                                  const FieldDecl *Field,
1651                                                  unsigned CVRQualifiers) {
1652  QualType FieldType = Field->getType();
1653
1654  if (!FieldType->isReferenceType())
1655    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1656
1657  const CGRecordLayout &RL =
1658    CGM.getTypes().getCGRecordLayout(Field->getParent());
1659  unsigned idx = RL.getLLVMFieldNo(Field);
1660  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1661
1662  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1663
1664  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1665  return MakeAddrLValue(V, FieldType, Alignment);
1666}
1667
1668LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
1669  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1670  const Expr *InitExpr = E->getInitializer();
1671  LValue Result = MakeAddrLValue(DeclPtr, E->getType());
1672
1673  EmitAnyExprToMem(InitExpr, DeclPtr, /*Volatile*/ false, /*Init*/ true);
1674
1675  return Result;
1676}
1677
1678LValue
1679CodeGenFunction::EmitConditionalOperatorLValue(const ConditionalOperator *E) {
1680  if (!E->isGLValue()) {
1681    // ?: here should be an aggregate.
1682    assert((hasAggregateLLVMType(E->getType()) &&
1683            !E->getType()->isAnyComplexType()) &&
1684           "Unexpected conditional operator!");
1685    return EmitAggExprToLValue(E);
1686  }
1687
1688  if (int Cond = ConstantFoldsToSimpleInteger(E->getCond())) {
1689    Expr *Live = Cond == 1 ? E->getLHS() : E->getRHS();
1690    if (Live)
1691      return EmitLValue(Live);
1692  }
1693
1694  llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
1695  llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
1696  llvm::BasicBlock *ContBlock = createBasicBlock("cond.end");
1697
1698  ConditionalEvaluation eval(*this);
1699
1700  if (E->getLHS())
1701    EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1702  else {
1703    Expr *save = E->getSAVE();
1704    assert(save && "VisitConditionalOperator - save is null");
1705    // Intentianlly not doing direct assignment to ConditionalSaveExprs[save]
1706    LValue SaveVal = EmitLValue(save);
1707    ConditionalSaveLValueExprs[save] = SaveVal;
1708    EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock);
1709  }
1710
1711  // Any temporaries created here are conditional.
1712  EmitBlock(LHSBlock);
1713  eval.begin(*this);
1714  LValue LHS = EmitLValue(E->getTrueExpr());
1715  eval.end(*this);
1716
1717  if (!LHS.isSimple())
1718    return EmitUnsupportedLValue(E, "conditional operator");
1719
1720  LHSBlock = Builder.GetInsertBlock();
1721  Builder.CreateBr(ContBlock);
1722
1723  // Any temporaries created here are conditional.
1724  EmitBlock(RHSBlock);
1725  eval.begin(*this);
1726  LValue RHS = EmitLValue(E->getRHS());
1727  eval.end(*this);
1728  if (!RHS.isSimple())
1729    return EmitUnsupportedLValue(E, "conditional operator");
1730  RHSBlock = Builder.GetInsertBlock();
1731
1732  EmitBlock(ContBlock);
1733
1734  llvm::PHINode *phi = Builder.CreatePHI(LHS.getAddress()->getType(),
1735                                         "cond-lvalue");
1736  phi->reserveOperandSpace(2);
1737  phi->addIncoming(LHS.getAddress(), LHSBlock);
1738  phi->addIncoming(RHS.getAddress(), RHSBlock);
1739  return MakeAddrLValue(phi, E->getType());
1740}
1741
1742/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1743/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1744/// otherwise if a cast is needed by the code generator in an lvalue context,
1745/// then it must mean that we need the address of an aggregate in order to
1746/// access one of its fields.  This can happen for all the reasons that casts
1747/// are permitted with aggregate result, including noop aggregate casts, and
1748/// cast from scalar to union.
1749LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1750  switch (E->getCastKind()) {
1751  case CK_ToVoid:
1752    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1753
1754  case CK_Dependent:
1755    llvm_unreachable("dependent cast kind in IR gen!");
1756
1757  case CK_GetObjCProperty: {
1758    LValue LV = EmitLValue(E->getSubExpr());
1759    assert(LV.isPropertyRef());
1760    RValue RV = EmitLoadOfPropertyRefLValue(LV);
1761
1762    // Property is an aggregate r-value.
1763    if (RV.isAggregate()) {
1764      return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
1765    }
1766
1767    // Implicit property returns an l-value.
1768    assert(RV.isScalar());
1769    return MakeAddrLValue(RV.getScalarVal(), E->getSubExpr()->getType());
1770  }
1771
1772  case CK_NoOp:
1773  case CK_LValueToRValue:
1774    if (!E->getSubExpr()->Classify(getContext()).isPRValue()
1775        || E->getType()->isRecordType())
1776      return EmitLValue(E->getSubExpr());
1777    // Fall through to synthesize a temporary.
1778
1779  case CK_BitCast:
1780  case CK_ArrayToPointerDecay:
1781  case CK_FunctionToPointerDecay:
1782  case CK_NullToMemberPointer:
1783  case CK_NullToPointer:
1784  case CK_IntegralToPointer:
1785  case CK_PointerToIntegral:
1786  case CK_PointerToBoolean:
1787  case CK_VectorSplat:
1788  case CK_IntegralCast:
1789  case CK_IntegralToBoolean:
1790  case CK_IntegralToFloating:
1791  case CK_FloatingToIntegral:
1792  case CK_FloatingToBoolean:
1793  case CK_FloatingCast:
1794  case CK_FloatingRealToComplex:
1795  case CK_FloatingComplexToReal:
1796  case CK_FloatingComplexToBoolean:
1797  case CK_FloatingComplexCast:
1798  case CK_FloatingComplexToIntegralComplex:
1799  case CK_IntegralRealToComplex:
1800  case CK_IntegralComplexToReal:
1801  case CK_IntegralComplexToBoolean:
1802  case CK_IntegralComplexCast:
1803  case CK_IntegralComplexToFloatingComplex:
1804  case CK_DerivedToBaseMemberPointer:
1805  case CK_BaseToDerivedMemberPointer:
1806  case CK_MemberPointerToBoolean:
1807  case CK_AnyPointerToBlockPointerCast: {
1808    // These casts only produce lvalues when we're binding a reference to a
1809    // temporary realized from a (converted) pure rvalue. Emit the expression
1810    // as a value, copy it into a temporary, and return an lvalue referring to
1811    // that temporary.
1812    llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
1813    EmitAnyExprToMem(E, V, false, false);
1814    return MakeAddrLValue(V, E->getType());
1815  }
1816
1817  case CK_Dynamic: {
1818    LValue LV = EmitLValue(E->getSubExpr());
1819    llvm::Value *V = LV.getAddress();
1820    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
1821    return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
1822  }
1823
1824  case CK_ConstructorConversion:
1825  case CK_UserDefinedConversion:
1826  case CK_AnyPointerToObjCPointerCast:
1827    return EmitLValue(E->getSubExpr());
1828
1829  case CK_UncheckedDerivedToBase:
1830  case CK_DerivedToBase: {
1831    const RecordType *DerivedClassTy =
1832      E->getSubExpr()->getType()->getAs<RecordType>();
1833    CXXRecordDecl *DerivedClassDecl =
1834      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1835
1836    LValue LV = EmitLValue(E->getSubExpr());
1837    llvm::Value *This = LV.getAddress();
1838
1839    // Perform the derived-to-base conversion
1840    llvm::Value *Base =
1841      GetAddressOfBaseClass(This, DerivedClassDecl,
1842                            E->path_begin(), E->path_end(),
1843                            /*NullCheckValue=*/false);
1844
1845    return MakeAddrLValue(Base, E->getType());
1846  }
1847  case CK_ToUnion:
1848    return EmitAggExprToLValue(E);
1849  case CK_BaseToDerived: {
1850    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
1851    CXXRecordDecl *DerivedClassDecl =
1852      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1853
1854    LValue LV = EmitLValue(E->getSubExpr());
1855
1856    // Perform the base-to-derived conversion
1857    llvm::Value *Derived =
1858      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
1859                               E->path_begin(), E->path_end(),
1860                               /*NullCheckValue=*/false);
1861
1862    return MakeAddrLValue(Derived, E->getType());
1863  }
1864  case CK_LValueBitCast: {
1865    // This must be a reinterpret_cast (or c-style equivalent).
1866    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
1867
1868    LValue LV = EmitLValue(E->getSubExpr());
1869    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1870                                           ConvertType(CE->getTypeAsWritten()));
1871    return MakeAddrLValue(V, E->getType());
1872  }
1873  case CK_ObjCObjectLValueCast: {
1874    LValue LV = EmitLValue(E->getSubExpr());
1875    QualType ToType = getContext().getLValueReferenceType(E->getType());
1876    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
1877                                           ConvertType(ToType));
1878    return MakeAddrLValue(V, E->getType());
1879  }
1880  }
1881
1882  llvm_unreachable("Unhandled lvalue cast kind?");
1883}
1884
1885LValue CodeGenFunction::EmitNullInitializationLValue(
1886                                              const CXXScalarValueInitExpr *E) {
1887  QualType Ty = E->getType();
1888  LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
1889  EmitNullInitialization(LV.getAddress(), Ty);
1890  return LV;
1891}
1892
1893LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
1894  assert(e->isGLValue() || e->getType()->isRecordType());
1895  llvm::Value *value = getOpaqueValueMapping(e);
1896  return MakeAddrLValue(value, e->getType());
1897}
1898
1899//===--------------------------------------------------------------------===//
1900//                             Expression Emission
1901//===--------------------------------------------------------------------===//
1902
1903
1904RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
1905                                     ReturnValueSlot ReturnValue) {
1906  // Builtins never have block type.
1907  if (E->getCallee()->getType()->isBlockPointerType())
1908    return EmitBlockCallExpr(E, ReturnValue);
1909
1910  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
1911    return EmitCXXMemberCallExpr(CE, ReturnValue);
1912
1913  const Decl *TargetDecl = 0;
1914  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
1915    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
1916      TargetDecl = DRE->getDecl();
1917      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
1918        if (unsigned builtinID = FD->getBuiltinID())
1919          return EmitBuiltinExpr(FD, builtinID, E);
1920    }
1921  }
1922
1923  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
1924    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
1925      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
1926
1927  if (isa<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
1928    // C++ [expr.pseudo]p1:
1929    //   The result shall only be used as the operand for the function call
1930    //   operator (), and the result of such a call has type void. The only
1931    //   effect is the evaluation of the postfix-expression before the dot or
1932    //   arrow.
1933    EmitScalarExpr(E->getCallee());
1934    return RValue::get(0);
1935  }
1936
1937  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
1938  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
1939                  E->arg_begin(), E->arg_end(), TargetDecl);
1940}
1941
1942LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
1943  // Comma expressions just emit their LHS then their RHS as an l-value.
1944  if (E->getOpcode() == BO_Comma) {
1945    EmitIgnoredExpr(E->getLHS());
1946    EnsureInsertPoint();
1947    return EmitLValue(E->getRHS());
1948  }
1949
1950  if (E->getOpcode() == BO_PtrMemD ||
1951      E->getOpcode() == BO_PtrMemI)
1952    return EmitPointerToDataMemberBinaryExpr(E);
1953
1954  assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
1955
1956  if (!hasAggregateLLVMType(E->getType())) {
1957    // __block variables need the RHS evaluated first.
1958    RValue RV = EmitAnyExpr(E->getRHS());
1959    LValue LV = EmitLValue(E->getLHS());
1960    EmitStoreThroughLValue(RV, LV, E->getType());
1961    return LV;
1962  }
1963
1964  if (E->getType()->isAnyComplexType())
1965    return EmitComplexAssignmentLValue(E);
1966
1967  return EmitAggExprToLValue(E);
1968}
1969
1970LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
1971  RValue RV = EmitCallExpr(E);
1972
1973  if (!RV.isScalar())
1974    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
1975
1976  assert(E->getCallReturnType()->isReferenceType() &&
1977         "Can't have a scalar return unless the return type is a "
1978         "reference type!");
1979
1980  return MakeAddrLValue(RV.getScalarVal(), E->getType());
1981}
1982
1983LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
1984  // FIXME: This shouldn't require another copy.
1985  return EmitAggExprToLValue(E);
1986}
1987
1988LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
1989  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
1990         && "binding l-value to type which needs a temporary");
1991  AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
1992  EmitCXXConstructExpr(E, Slot);
1993  return MakeAddrLValue(Slot.getAddr(), E->getType());
1994}
1995
1996LValue
1997CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
1998  return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
1999}
2000
2001LValue
2002CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
2003  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
2004  Slot.setLifetimeExternallyManaged();
2005  EmitAggExpr(E->getSubExpr(), Slot);
2006  EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
2007  return MakeAddrLValue(Slot.getAddr(), E->getType());
2008}
2009
2010LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
2011  RValue RV = EmitObjCMessageExpr(E);
2012
2013  if (!RV.isScalar())
2014    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2015
2016  assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
2017         "Can't have a scalar return unless the return type is a "
2018         "reference type!");
2019
2020  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2021}
2022
2023LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
2024  llvm::Value *V =
2025    CGM.getObjCRuntime().GetSelector(Builder, E->getSelector(), true);
2026  return MakeAddrLValue(V, E->getType());
2027}
2028
2029llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
2030                                             const ObjCIvarDecl *Ivar) {
2031  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
2032}
2033
2034LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
2035                                          llvm::Value *BaseValue,
2036                                          const ObjCIvarDecl *Ivar,
2037                                          unsigned CVRQualifiers) {
2038  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
2039                                                   Ivar, CVRQualifiers);
2040}
2041
2042LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
2043  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
2044  llvm::Value *BaseValue = 0;
2045  const Expr *BaseExpr = E->getBase();
2046  Qualifiers BaseQuals;
2047  QualType ObjectTy;
2048  if (E->isArrow()) {
2049    BaseValue = EmitScalarExpr(BaseExpr);
2050    ObjectTy = BaseExpr->getType()->getPointeeType();
2051    BaseQuals = ObjectTy.getQualifiers();
2052  } else {
2053    LValue BaseLV = EmitLValue(BaseExpr);
2054    // FIXME: this isn't right for bitfields.
2055    BaseValue = BaseLV.getAddress();
2056    ObjectTy = BaseExpr->getType();
2057    BaseQuals = ObjectTy.getQualifiers();
2058  }
2059
2060  LValue LV =
2061    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
2062                      BaseQuals.getCVRQualifiers());
2063  setObjCGCLValueClass(getContext(), E, LV);
2064  return LV;
2065}
2066
2067LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
2068  // Can only get l-value for message expression returning aggregate type
2069  RValue RV = EmitAnyExprToTemp(E);
2070  return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2071}
2072
2073RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
2074                                 ReturnValueSlot ReturnValue,
2075                                 CallExpr::const_arg_iterator ArgBeg,
2076                                 CallExpr::const_arg_iterator ArgEnd,
2077                                 const Decl *TargetDecl) {
2078  // Get the actual function type. The callee type will always be a pointer to
2079  // function type or a block pointer type.
2080  assert(CalleeType->isFunctionPointerType() &&
2081         "Call must have function pointer type!");
2082
2083  CalleeType = getContext().getCanonicalType(CalleeType);
2084
2085  const FunctionType *FnType
2086    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
2087
2088  CallArgList Args;
2089  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
2090
2091  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
2092                  Callee, ReturnValue, Args, TargetDecl);
2093}
2094
2095LValue CodeGenFunction::
2096EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
2097  llvm::Value *BaseV;
2098  if (E->getOpcode() == BO_PtrMemI)
2099    BaseV = EmitScalarExpr(E->getLHS());
2100  else
2101    BaseV = EmitLValue(E->getLHS()).getAddress();
2102
2103  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
2104
2105  const MemberPointerType *MPT
2106    = E->getRHS()->getType()->getAs<MemberPointerType>();
2107
2108  llvm::Value *AddV =
2109    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
2110
2111  return MakeAddrLValue(AddV, MPT->getPointeeType());
2112}
2113