CGExpr.cpp revision 03e80030515c800d1ab44125b9052dfffd1bd04c 
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 "CGDebugInfo.h"
19#include "CGRecordLayout.h"
20#include "CGObjCRuntime.h"
21#include "clang/AST/ASTContext.h"
22#include "clang/AST/DeclObjC.h"
23#include "llvm/Intrinsics.h"
24#include "clang/Frontend/CodeGenOptions.h"
25#include "llvm/Target/TargetData.h"
26using namespace clang;
27using namespace CodeGen;
28
29//===--------------------------------------------------------------------===//
30//                        Miscellaneous Helper Methods
31//===--------------------------------------------------------------------===//
32
33llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
34  unsigned addressSpace =
35    cast<llvm::PointerType>(value->getType())->getAddressSpace();
36
37  const llvm::PointerType *destType = Int8PtrTy;
38  if (addressSpace)
39    destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
40
41  if (value->getType() == destType) return value;
42  return Builder.CreateBitCast(value, destType);
43}
44
45/// CreateTempAlloca - This creates a alloca and inserts it into the entry
46/// block.
47llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
48                                                    const llvm::Twine &Name) {
49  if (!Builder.isNamePreserving())
50    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
51  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
52}
53
54void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
55                                     llvm::Value *Init) {
56  llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
57  llvm::BasicBlock *Block = AllocaInsertPt->getParent();
58  Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
59}
60
61llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
62                                                const llvm::Twine &Name) {
63  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
64  // FIXME: Should we prefer the preferred type alignment here?
65  CharUnits Align = getContext().getTypeAlignInChars(Ty);
66  Alloc->setAlignment(Align.getQuantity());
67  return Alloc;
68}
69
70llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
71                                                 const llvm::Twine &Name) {
72  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
73  // FIXME: Should we prefer the preferred type alignment here?
74  CharUnits Align = getContext().getTypeAlignInChars(Ty);
75  Alloc->setAlignment(Align.getQuantity());
76  return Alloc;
77}
78
79/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
80/// expression and compare the result against zero, returning an Int1Ty value.
81llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
82  if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
83    llvm::Value *MemPtr = EmitScalarExpr(E);
84    return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT);
85  }
86
87  QualType BoolTy = getContext().BoolTy;
88  if (!E->getType()->isAnyComplexType())
89    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
90
91  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
92}
93
94/// EmitIgnoredExpr - Emit code to compute the specified expression,
95/// ignoring the result.
96void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
97  if (E->isRValue())
98    return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
99
100  // Just emit it as an l-value and drop the result.
101  EmitLValue(E);
102}
103
104/// EmitAnyExpr - Emit code to compute the specified expression which
105/// can have any type.  The result is returned as an RValue struct.
106/// If this is an aggregate expression, AggSlot indicates where the
107/// result should be returned.
108RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot AggSlot,
109                                    bool IgnoreResult) {
110  if (!hasAggregateLLVMType(E->getType()))
111    return RValue::get(EmitScalarExpr(E, IgnoreResult));
112  else if (E->getType()->isAnyComplexType())
113    return RValue::getComplex(EmitComplexExpr(E, IgnoreResult, IgnoreResult));
114
115  EmitAggExpr(E, AggSlot, IgnoreResult);
116  return AggSlot.asRValue();
117}
118
119/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
120/// always be accessible even if no aggregate location is provided.
121RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
122  AggValueSlot AggSlot = AggValueSlot::ignored();
123
124  if (hasAggregateLLVMType(E->getType()) &&
125      !E->getType()->isAnyComplexType())
126    AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
127  return EmitAnyExpr(E, AggSlot);
128}
129
130/// EmitAnyExprToMem - Evaluate an expression into a given memory
131/// location.
132void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
133                                       llvm::Value *Location,
134                                       Qualifiers Quals,
135                                       bool IsInit) {
136  if (E->getType()->isAnyComplexType())
137    EmitComplexExprIntoAddr(E, Location, Quals.hasVolatile());
138  else if (hasAggregateLLVMType(E->getType()))
139    EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals, IsInit));
140  else {
141    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
142    LValue LV = MakeAddrLValue(Location, E->getType());
143    EmitStoreThroughLValue(RV, LV, E->getType());
144  }
145}
146
147namespace {
148/// \brief An adjustment to be made to the temporary created when emitting a
149/// reference binding, which accesses a particular subobject of that temporary.
150  struct SubobjectAdjustment {
151    enum { DerivedToBaseAdjustment, FieldAdjustment } Kind;
152
153    union {
154      struct {
155        const CastExpr *BasePath;
156        const CXXRecordDecl *DerivedClass;
157      } DerivedToBase;
158
159      FieldDecl *Field;
160    };
161
162    SubobjectAdjustment(const CastExpr *BasePath,
163                        const CXXRecordDecl *DerivedClass)
164      : Kind(DerivedToBaseAdjustment) {
165      DerivedToBase.BasePath = BasePath;
166      DerivedToBase.DerivedClass = DerivedClass;
167    }
168
169    SubobjectAdjustment(FieldDecl *Field)
170      : Kind(FieldAdjustment) {
171      this->Field = Field;
172    }
173  };
174}
175
176static llvm::Value *
177CreateReferenceTemporary(CodeGenFunction& CGF, QualType Type,
178                         const NamedDecl *InitializedDecl) {
179  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
180    if (VD->hasGlobalStorage()) {
181      llvm::SmallString<256> Name;
182      llvm::raw_svector_ostream Out(Name);
183      CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Out);
184      Out.flush();
185
186      const llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
187
188      // Create the reference temporary.
189      llvm::GlobalValue *RefTemp =
190        new llvm::GlobalVariable(CGF.CGM.getModule(),
191                                 RefTempTy, /*isConstant=*/false,
192                                 llvm::GlobalValue::InternalLinkage,
193                                 llvm::Constant::getNullValue(RefTempTy),
194                                 Name.str());
195      return RefTemp;
196    }
197  }
198
199  return CGF.CreateMemTemp(Type, "ref.tmp");
200}
201
202static llvm::Value *
203EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
204                            llvm::Value *&ReferenceTemporary,
205                            const CXXDestructorDecl *&ReferenceTemporaryDtor,
206                            QualType &ObjCARCReferenceLifetimeType,
207                            const NamedDecl *InitializedDecl) {
208  ObjCARCReferenceLifetimeType = QualType();
209
210  // Look through expressions for materialized temporaries (for now).
211  if (isa<MaterializeTemporaryExpr>(E))
212    E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr();
213
214  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
215    E = DAE->getExpr();
216
217  if (const ExprWithCleanups *TE = dyn_cast<ExprWithCleanups>(E)) {
218    CodeGenFunction::RunCleanupsScope Scope(CGF);
219
220    return EmitExprForReferenceBinding(CGF, TE->getSubExpr(),
221                                       ReferenceTemporary,
222                                       ReferenceTemporaryDtor,
223                                       ObjCARCReferenceLifetimeType,
224                                       InitializedDecl);
225  }
226
227  if (const ObjCPropertyRefExpr *PRE =
228      dyn_cast<ObjCPropertyRefExpr>(E->IgnoreParenImpCasts()))
229    if (PRE->getGetterResultType()->isReferenceType())
230      E = PRE;
231
232  RValue RV;
233  if (E->isGLValue()) {
234    // Emit the expression as an lvalue.
235    LValue LV = CGF.EmitLValue(E);
236    if (LV.isPropertyRef()) {
237      RV = CGF.EmitLoadOfPropertyRefLValue(LV);
238      return RV.getScalarVal();
239    }
240    if (LV.isSimple())
241      return LV.getAddress();
242
243    // We have to load the lvalue.
244    RV = CGF.EmitLoadOfLValue(LV, E->getType());
245  } else {
246    llvm::SmallVector<SubobjectAdjustment, 2> Adjustments;
247    while (true) {
248      E = E->IgnoreParens();
249
250      if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
251        if ((CE->getCastKind() == CK_DerivedToBase ||
252             CE->getCastKind() == CK_UncheckedDerivedToBase) &&
253            E->getType()->isRecordType()) {
254          E = CE->getSubExpr();
255          CXXRecordDecl *Derived
256            = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
257          Adjustments.push_back(SubobjectAdjustment(CE, Derived));
258          continue;
259        }
260
261        if (CE->getCastKind() == CK_NoOp) {
262          E = CE->getSubExpr();
263          continue;
264        }
265      } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
266        if (!ME->isArrow() && ME->getBase()->isRValue()) {
267          assert(ME->getBase()->getType()->isRecordType());
268          if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
269            E = ME->getBase();
270            Adjustments.push_back(SubobjectAdjustment(Field));
271            continue;
272          }
273        }
274      }
275
276      if (const OpaqueValueExpr *opaque = dyn_cast<OpaqueValueExpr>(E))
277        if (opaque->getType()->isRecordType())
278          return CGF.EmitOpaqueValueLValue(opaque).getAddress();
279
280      // Nothing changed.
281      break;
282    }
283
284    // Create a reference temporary if necessary.
285    AggValueSlot AggSlot = AggValueSlot::ignored();
286    if (CGF.hasAggregateLLVMType(E->getType()) &&
287        !E->getType()->isAnyComplexType()) {
288      ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
289                                                    InitializedDecl);
290      AggSlot = AggValueSlot::forAddr(ReferenceTemporary, Qualifiers(),
291                                      InitializedDecl != 0);
292    }
293
294    if (InitializedDecl) {
295      // Get the destructor for the reference temporary.
296      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
297        CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
298        if (!ClassDecl->hasTrivialDestructor())
299          ReferenceTemporaryDtor = ClassDecl->getDestructor();
300      }
301      else if (CGF.getContext().getLangOptions().ObjCAutoRefCount) {
302        if (const ValueDecl *InitVD = dyn_cast<ValueDecl>(InitializedDecl)) {
303          if (const ReferenceType *RefType
304                                  = InitVD->getType()->getAs<ReferenceType>()) {
305            QualType PointeeType = RefType->getPointeeType();
306            if (PointeeType->isObjCLifetimeType() &&
307                PointeeType.getObjCLifetime() != Qualifiers::OCL_ExplicitNone) {
308              // Objective-C++ ARC: We're binding a reference to
309              // lifetime-qualified type to a temporary, so we need to extend
310              // the lifetime of the temporary with appropriate retain/release/
311              // autorelease calls.
312              ObjCARCReferenceLifetimeType = PointeeType;
313
314              // Create a temporary variable that we can bind the reference to.
315              ReferenceTemporary = CreateReferenceTemporary(CGF, PointeeType,
316                                                            InitializedDecl);
317
318              unsigned Alignment =
319                CGF.getContext().getTypeAlignInChars(PointeeType).getQuantity();
320              LValue lvalue =
321                CGF.MakeAddrLValue(ReferenceTemporary, PointeeType, Alignment);
322
323              CGF.EmitScalarInit(E, InitVD, lvalue, false);
324              return ReferenceTemporary;
325            }
326          }
327        }
328      }
329    }
330
331    RV = CGF.EmitAnyExpr(E, AggSlot);
332
333    // Check if need to perform derived-to-base casts and/or field accesses, to
334    // get from the temporary object we created (and, potentially, for which we
335    // extended the lifetime) to the subobject we're binding the reference to.
336    if (!Adjustments.empty()) {
337      llvm::Value *Object = RV.getAggregateAddr();
338      for (unsigned I = Adjustments.size(); I != 0; --I) {
339        SubobjectAdjustment &Adjustment = Adjustments[I-1];
340        switch (Adjustment.Kind) {
341        case SubobjectAdjustment::DerivedToBaseAdjustment:
342          Object =
343              CGF.GetAddressOfBaseClass(Object,
344                                        Adjustment.DerivedToBase.DerivedClass,
345                              Adjustment.DerivedToBase.BasePath->path_begin(),
346                              Adjustment.DerivedToBase.BasePath->path_end(),
347                                        /*NullCheckValue=*/false);
348          break;
349
350        case SubobjectAdjustment::FieldAdjustment: {
351          LValue LV =
352            CGF.EmitLValueForField(Object, Adjustment.Field, 0);
353          if (LV.isSimple()) {
354            Object = LV.getAddress();
355            break;
356          }
357
358          // For non-simple lvalues, we actually have to create a copy of
359          // the object we're binding to.
360          QualType T = Adjustment.Field->getType().getNonReferenceType()
361                                                  .getUnqualifiedType();
362          Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
363          LValue TempLV = CGF.MakeAddrLValue(Object,
364                                             Adjustment.Field->getType());
365          CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV, T), TempLV, T);
366          break;
367        }
368
369        }
370      }
371
372      return Object;
373    }
374  }
375
376  if (RV.isAggregate())
377    return RV.getAggregateAddr();
378
379  // Create a temporary variable that we can bind the reference to.
380  ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
381                                                InitializedDecl);
382
383
384  unsigned Alignment =
385    CGF.getContext().getTypeAlignInChars(E->getType()).getQuantity();
386  if (RV.isScalar())
387    CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
388                          /*Volatile=*/false, Alignment, E->getType());
389  else
390    CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
391                           /*Volatile=*/false);
392  return ReferenceTemporary;
393}
394
395RValue
396CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
397                                            const NamedDecl *InitializedDecl) {
398  llvm::Value *ReferenceTemporary = 0;
399  const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
400  QualType ObjCARCReferenceLifetimeType;
401  llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
402                                                   ReferenceTemporaryDtor,
403                                                   ObjCARCReferenceLifetimeType,
404                                                   InitializedDecl);
405  if (!ReferenceTemporaryDtor && ObjCARCReferenceLifetimeType.isNull())
406    return RValue::get(Value);
407
408  // Make sure to call the destructor for the reference temporary.
409  const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl);
410  if (VD && VD->hasGlobalStorage()) {
411    if (ReferenceTemporaryDtor) {
412      llvm::Constant *DtorFn =
413        CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
414      EmitCXXGlobalDtorRegistration(DtorFn,
415                                    cast<llvm::Constant>(ReferenceTemporary));
416    } else {
417      assert(!ObjCARCReferenceLifetimeType.isNull());
418      // Note: We intentionally do not register a global "destructor" to
419      // release the object.
420    }
421
422    return RValue::get(Value);
423  }
424
425  if (ReferenceTemporaryDtor)
426    PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
427  else {
428    switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
429    case Qualifiers::OCL_None:
430      llvm_unreachable("Not a reference temporary that needs to be deallocated");
431      break;
432
433    case Qualifiers::OCL_ExplicitNone:
434    case Qualifiers::OCL_Autoreleasing:
435      // Nothing to do.
436      break;
437
438    case Qualifiers::OCL_Strong:
439      PushARCReleaseCleanup(getARCCleanupKind(), ObjCARCReferenceLifetimeType,
440                            ReferenceTemporary,
441                            VD && VD->hasAttr<ObjCPreciseLifetimeAttr>());
442      break;
443
444    case Qualifiers::OCL_Weak:
445      // __weak objects always get EH cleanups; otherwise, exceptions
446      // could cause really nasty crashes instead of mere leaks.
447      PushARCWeakReleaseCleanup(NormalAndEHCleanup,
448                                ObjCARCReferenceLifetimeType,
449                                ReferenceTemporary);
450      break;
451    }
452  }
453
454  return RValue::get(Value);
455}
456
457
458/// getAccessedFieldNo - Given an encoded value and a result number, return the
459/// input field number being accessed.
460unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
461                                             const llvm::Constant *Elts) {
462  if (isa<llvm::ConstantAggregateZero>(Elts))
463    return 0;
464
465  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
466}
467
468void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
469  if (!CatchUndefined)
470    return;
471
472  // This needs to be to the standard address space.
473  Address = Builder.CreateBitCast(Address, Int8PtrTy);
474
475  const llvm::Type *IntPtrT = IntPtrTy;
476  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, &IntPtrT, 1);
477
478  // In time, people may want to control this and use a 1 here.
479  llvm::Value *Arg = Builder.getFalse();
480  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
481  llvm::BasicBlock *Cont = createBasicBlock();
482  llvm::BasicBlock *Check = createBasicBlock();
483  llvm::Value *NegativeOne = llvm::ConstantInt::get(IntPtrTy, -1ULL);
484  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
485
486  EmitBlock(Check);
487  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
488                                        llvm::ConstantInt::get(IntPtrTy, Size)),
489                       Cont, getTrapBB());
490  EmitBlock(Cont);
491}
492
493
494CodeGenFunction::ComplexPairTy CodeGenFunction::
495EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
496                         bool isInc, bool isPre) {
497  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
498                                            LV.isVolatileQualified());
499
500  llvm::Value *NextVal;
501  if (isa<llvm::IntegerType>(InVal.first->getType())) {
502    uint64_t AmountVal = isInc ? 1 : -1;
503    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
504
505    // Add the inc/dec to the real part.
506    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
507  } else {
508    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
509    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
510    if (!isInc)
511      FVal.changeSign();
512    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
513
514    // Add the inc/dec to the real part.
515    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
516  }
517
518  ComplexPairTy IncVal(NextVal, InVal.second);
519
520  // Store the updated result through the lvalue.
521  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
522
523  // If this is a postinc, return the value read from memory, otherwise use the
524  // updated value.
525  return isPre ? IncVal : InVal;
526}
527
528
529//===----------------------------------------------------------------------===//
530//                         LValue Expression Emission
531//===----------------------------------------------------------------------===//
532
533RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
534  if (Ty->isVoidType())
535    return RValue::get(0);
536
537  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
538    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
539    llvm::Value *U = llvm::UndefValue::get(EltTy);
540    return RValue::getComplex(std::make_pair(U, U));
541  }
542
543  // If this is a use of an undefined aggregate type, the aggregate must have an
544  // identifiable address.  Just because the contents of the value are undefined
545  // doesn't mean that the address can't be taken and compared.
546  if (hasAggregateLLVMType(Ty)) {
547    llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
548    return RValue::getAggregate(DestPtr);
549  }
550
551  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
552}
553
554RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
555                                              const char *Name) {
556  ErrorUnsupported(E, Name);
557  return GetUndefRValue(E->getType());
558}
559
560LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
561                                              const char *Name) {
562  ErrorUnsupported(E, Name);
563  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
564  return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
565}
566
567LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
568  LValue LV = EmitLValue(E);
569  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
570    EmitCheck(LV.getAddress(),
571              getContext().getTypeSizeInChars(E->getType()).getQuantity());
572  return LV;
573}
574
575/// EmitLValue - Emit code to compute a designator that specifies the location
576/// of the expression.
577///
578/// This can return one of two things: a simple address or a bitfield reference.
579/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
580/// an LLVM pointer type.
581///
582/// If this returns a bitfield reference, nothing about the pointee type of the
583/// LLVM value is known: For example, it may not be a pointer to an integer.
584///
585/// If this returns a normal address, and if the lvalue's C type is fixed size,
586/// this method guarantees that the returned pointer type will point to an LLVM
587/// type of the same size of the lvalue's type.  If the lvalue has a variable
588/// length type, this is not possible.
589///
590LValue CodeGenFunction::EmitLValue(const Expr *E) {
591  switch (E->getStmtClass()) {
592  default: return EmitUnsupportedLValue(E, "l-value expression");
593
594  case Expr::ObjCSelectorExprClass:
595  return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
596  case Expr::ObjCIsaExprClass:
597    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
598  case Expr::BinaryOperatorClass:
599    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
600  case Expr::CompoundAssignOperatorClass:
601    if (!E->getType()->isAnyComplexType())
602      return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
603    return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
604  case Expr::CallExprClass:
605  case Expr::CXXMemberCallExprClass:
606  case Expr::CXXOperatorCallExprClass:
607    return EmitCallExprLValue(cast<CallExpr>(E));
608  case Expr::VAArgExprClass:
609    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
610  case Expr::DeclRefExprClass:
611    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
612  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
613  case Expr::GenericSelectionExprClass:
614    return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
615  case Expr::PredefinedExprClass:
616    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
617  case Expr::StringLiteralClass:
618    return EmitStringLiteralLValue(cast<StringLiteral>(E));
619  case Expr::ObjCEncodeExprClass:
620    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
621
622  case Expr::BlockDeclRefExprClass:
623    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
624
625  case Expr::CXXTemporaryObjectExprClass:
626  case Expr::CXXConstructExprClass:
627    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
628  case Expr::CXXBindTemporaryExprClass:
629    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
630  case Expr::ExprWithCleanupsClass:
631    return EmitExprWithCleanupsLValue(cast<ExprWithCleanups>(E));
632  case Expr::CXXScalarValueInitExprClass:
633    return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
634  case Expr::CXXDefaultArgExprClass:
635    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
636  case Expr::CXXTypeidExprClass:
637    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
638
639  case Expr::ObjCMessageExprClass:
640    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
641  case Expr::ObjCIvarRefExprClass:
642    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
643  case Expr::ObjCPropertyRefExprClass:
644    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
645  case Expr::StmtExprClass:
646    return EmitStmtExprLValue(cast<StmtExpr>(E));
647  case Expr::UnaryOperatorClass:
648    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
649  case Expr::ArraySubscriptExprClass:
650    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
651  case Expr::ExtVectorElementExprClass:
652    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
653  case Expr::MemberExprClass:
654    return EmitMemberExpr(cast<MemberExpr>(E));
655  case Expr::CompoundLiteralExprClass:
656    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
657  case Expr::ConditionalOperatorClass:
658    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
659  case Expr::BinaryConditionalOperatorClass:
660    return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
661  case Expr::ChooseExprClass:
662    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
663  case Expr::OpaqueValueExprClass:
664    return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
665  case Expr::ImplicitCastExprClass:
666  case Expr::CStyleCastExprClass:
667  case Expr::CXXFunctionalCastExprClass:
668  case Expr::CXXStaticCastExprClass:
669  case Expr::CXXDynamicCastExprClass:
670  case Expr::CXXReinterpretCastExprClass:
671  case Expr::CXXConstCastExprClass:
672  case Expr::ObjCBridgedCastExprClass:
673    return EmitCastLValue(cast<CastExpr>(E));
674
675  case Expr::MaterializeTemporaryExprClass:
676    return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
677  }
678}
679
680llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue) {
681  return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
682                          lvalue.getAlignment(), lvalue.getType(),
683                          lvalue.getTBAAInfo());
684}
685
686llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
687                                              unsigned Alignment, QualType Ty,
688                                              llvm::MDNode *TBAAInfo) {
689  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
690  if (Volatile)
691    Load->setVolatile(true);
692  if (Alignment)
693    Load->setAlignment(Alignment);
694  if (TBAAInfo)
695    CGM.DecorateInstruction(Load, TBAAInfo);
696
697  return EmitFromMemory(Load, Ty);
698}
699
700static bool isBooleanUnderlyingType(QualType Ty) {
701  if (const EnumType *ET = dyn_cast<EnumType>(Ty))
702    return ET->getDecl()->getIntegerType()->isBooleanType();
703  return false;
704}
705
706llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
707  // Bool has a different representation in memory than in registers.
708  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
709    // This should really always be an i1, but sometimes it's already
710    // an i8, and it's awkward to track those cases down.
711    if (Value->getType()->isIntegerTy(1))
712      return Builder.CreateZExt(Value, Builder.getInt8Ty(), "frombool");
713    assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
714  }
715
716  return Value;
717}
718
719llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
720  // Bool has a different representation in memory than in registers.
721  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
722    assert(Value->getType()->isIntegerTy(8) && "memory rep of bool not i8");
723    return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
724  }
725
726  return Value;
727}
728
729void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
730                                        bool Volatile, unsigned Alignment,
731                                        QualType Ty,
732                                        llvm::MDNode *TBAAInfo) {
733  Value = EmitToMemory(Value, Ty);
734  llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
735  if (Alignment)
736    Store->setAlignment(Alignment);
737  if (TBAAInfo)
738    CGM.DecorateInstruction(Store, TBAAInfo);
739}
740
741void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue) {
742  EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
743                    lvalue.getAlignment(), lvalue.getType(),
744                    lvalue.getTBAAInfo());
745}
746
747/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
748/// method emits the address of the lvalue, then loads the result as an rvalue,
749/// returning the rvalue.
750RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
751  if (LV.isObjCWeak()) {
752    // load of a __weak object.
753    llvm::Value *AddrWeakObj = LV.getAddress();
754    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
755                                                             AddrWeakObj));
756  }
757  if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak)
758    return RValue::get(EmitARCLoadWeak(LV.getAddress()));
759
760  if (LV.isSimple()) {
761    llvm::Value *Ptr = LV.getAddress();
762
763    // Functions are l-values that don't require loading.
764    if (ExprType->isFunctionType())
765      return RValue::get(Ptr);
766
767    // Everything needs a load.
768    return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
769                                        LV.getAlignment(), ExprType,
770                                        LV.getTBAAInfo()));
771
772  }
773
774  if (LV.isVectorElt()) {
775    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
776                                          LV.isVolatileQualified(), "tmp");
777    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
778                                                    "vecext"));
779  }
780
781  // If this is a reference to a subset of the elements of a vector, either
782  // shuffle the input or extract/insert them as appropriate.
783  if (LV.isExtVectorElt())
784    return EmitLoadOfExtVectorElementLValue(LV, ExprType);
785
786  if (LV.isBitField())
787    return EmitLoadOfBitfieldLValue(LV, ExprType);
788
789  assert(LV.isPropertyRef() && "Unknown LValue type!");
790  return EmitLoadOfPropertyRefLValue(LV);
791}
792
793RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
794                                                 QualType ExprType) {
795  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
796
797  // Get the output type.
798  const llvm::Type *ResLTy = ConvertType(ExprType);
799  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
800
801  // Compute the result as an OR of all of the individual component accesses.
802  llvm::Value *Res = 0;
803  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
804    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
805
806    // Get the field pointer.
807    llvm::Value *Ptr = LV.getBitFieldBaseAddr();
808
809    // Only offset by the field index if used, so that incoming values are not
810    // required to be structures.
811    if (AI.FieldIndex)
812      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
813
814    // Offset by the byte offset, if used.
815    if (!AI.FieldByteOffset.isZero()) {
816      Ptr = EmitCastToVoidPtr(Ptr);
817      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
818                                       "bf.field.offs");
819    }
820
821    // Cast to the access type.
822    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(getLLVMContext(),
823                                                     AI.AccessWidth,
824                              CGM.getContext().getTargetAddressSpace(ExprType));
825    Ptr = Builder.CreateBitCast(Ptr, PTy);
826
827    // Perform the load.
828    llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
829    if (!AI.AccessAlignment.isZero())
830      Load->setAlignment(AI.AccessAlignment.getQuantity());
831
832    // Shift out unused low bits and mask out unused high bits.
833    llvm::Value *Val = Load;
834    if (AI.FieldBitStart)
835      Val = Builder.CreateLShr(Load, AI.FieldBitStart);
836    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
837                                                            AI.TargetBitWidth),
838                            "bf.clear");
839
840    // Extend or truncate to the target size.
841    if (AI.AccessWidth < ResSizeInBits)
842      Val = Builder.CreateZExt(Val, ResLTy);
843    else if (AI.AccessWidth > ResSizeInBits)
844      Val = Builder.CreateTrunc(Val, ResLTy);
845
846    // Shift into place, and OR into the result.
847    if (AI.TargetBitOffset)
848      Val = Builder.CreateShl(Val, AI.TargetBitOffset);
849    Res = Res ? Builder.CreateOr(Res, Val) : Val;
850  }
851
852  // If the bit-field is signed, perform the sign-extension.
853  //
854  // FIXME: This can easily be folded into the load of the high bits, which
855  // could also eliminate the mask of high bits in some situations.
856  if (Info.isSigned()) {
857    unsigned ExtraBits = ResSizeInBits - Info.getSize();
858    if (ExtraBits)
859      Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
860                               ExtraBits, "bf.val.sext");
861  }
862
863  return RValue::get(Res);
864}
865
866// If this is a reference to a subset of the elements of a vector, create an
867// appropriate shufflevector.
868RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
869                                                         QualType ExprType) {
870  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
871                                        LV.isVolatileQualified(), "tmp");
872
873  const llvm::Constant *Elts = LV.getExtVectorElts();
874
875  // If the result of the expression is a non-vector type, we must be extracting
876  // a single element.  Just codegen as an extractelement.
877  const VectorType *ExprVT = ExprType->getAs<VectorType>();
878  if (!ExprVT) {
879    unsigned InIdx = getAccessedFieldNo(0, Elts);
880    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
881    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
882  }
883
884  // Always use shuffle vector to try to retain the original program structure
885  unsigned NumResultElts = ExprVT->getNumElements();
886
887  llvm::SmallVector<llvm::Constant*, 4> Mask;
888  for (unsigned i = 0; i != NumResultElts; ++i) {
889    unsigned InIdx = getAccessedFieldNo(i, Elts);
890    Mask.push_back(llvm::ConstantInt::get(Int32Ty, InIdx));
891  }
892
893  llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
894  Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()),
895                                    MaskV, "tmp");
896  return RValue::get(Vec);
897}
898
899
900
901/// EmitStoreThroughLValue - Store the specified rvalue into the specified
902/// lvalue, where both are guaranteed to the have the same type, and that type
903/// is 'Ty'.
904void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
905                                             QualType Ty) {
906  if (!Dst.isSimple()) {
907    if (Dst.isVectorElt()) {
908      // Read/modify/write the vector, inserting the new element.
909      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
910                                            Dst.isVolatileQualified(), "tmp");
911      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
912                                        Dst.getVectorIdx(), "vecins");
913      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
914      return;
915    }
916
917    // If this is an update of extended vector elements, insert them as
918    // appropriate.
919    if (Dst.isExtVectorElt())
920      return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
921
922    if (Dst.isBitField())
923      return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
924
925    assert(Dst.isPropertyRef() && "Unknown LValue type");
926    return EmitStoreThroughPropertyRefLValue(Src, Dst);
927  }
928
929  // There's special magic for assigning into an ARC-qualified l-value.
930  if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) {
931    switch (Lifetime) {
932    case Qualifiers::OCL_None:
933      llvm_unreachable("present but none");
934
935    case Qualifiers::OCL_ExplicitNone:
936      // nothing special
937      break;
938
939    case Qualifiers::OCL_Strong:
940      EmitARCStoreStrong(Dst, Ty, Src.getScalarVal(), /*ignore*/ true);
941      return;
942
943    case Qualifiers::OCL_Weak:
944      EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
945      return;
946
947    case Qualifiers::OCL_Autoreleasing:
948      Src = RValue::get(EmitObjCExtendObjectLifetime(Ty, Src.getScalarVal()));
949      // fall into the normal path
950      break;
951    }
952  }
953
954  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
955    // load of a __weak object.
956    llvm::Value *LvalueDst = Dst.getAddress();
957    llvm::Value *src = Src.getScalarVal();
958     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
959    return;
960  }
961
962  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
963    // load of a __strong object.
964    llvm::Value *LvalueDst = Dst.getAddress();
965    llvm::Value *src = Src.getScalarVal();
966    if (Dst.isObjCIvar()) {
967      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
968      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
969      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
970      llvm::Value *dst = RHS;
971      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
972      llvm::Value *LHS =
973        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
974      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
975      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
976                                              BytesBetween);
977    } else if (Dst.isGlobalObjCRef()) {
978      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
979                                                Dst.isThreadLocalRef());
980    }
981    else
982      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
983    return;
984  }
985
986  assert(Src.isScalar() && "Can't emit an agg store with this method");
987  EmitStoreOfScalar(Src.getScalarVal(), Dst);
988}
989
990void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
991                                                     QualType Ty,
992                                                     llvm::Value **Result) {
993  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
994
995  // Get the output type.
996  const llvm::Type *ResLTy = ConvertTypeForMem(Ty);
997  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
998
999  // Get the source value, truncated to the width of the bit-field.
1000  llvm::Value *SrcVal = Src.getScalarVal();
1001
1002  if (Ty->isBooleanType())
1003    SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
1004
1005  SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
1006                                                                Info.getSize()),
1007                             "bf.value");
1008
1009  // Return the new value of the bit-field, if requested.
1010  if (Result) {
1011    // Cast back to the proper type for result.
1012    const llvm::Type *SrcTy = Src.getScalarVal()->getType();
1013    llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
1014                                                   "bf.reload.val");
1015
1016    // Sign extend if necessary.
1017    if (Info.isSigned()) {
1018      unsigned ExtraBits = ResSizeInBits - Info.getSize();
1019      if (ExtraBits)
1020        ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
1021                                       ExtraBits, "bf.reload.sext");
1022    }
1023
1024    *Result = ReloadVal;
1025  }
1026
1027  // Iterate over the components, writing each piece to memory.
1028  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
1029    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
1030
1031    // Get the field pointer.
1032    llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
1033    unsigned addressSpace =
1034      cast<llvm::PointerType>(Ptr->getType())->getAddressSpace();
1035
1036    // Only offset by the field index if used, so that incoming values are not
1037    // required to be structures.
1038    if (AI.FieldIndex)
1039      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
1040
1041    // Offset by the byte offset, if used.
1042    if (!AI.FieldByteOffset.isZero()) {
1043      Ptr = EmitCastToVoidPtr(Ptr);
1044      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
1045                                       "bf.field.offs");
1046    }
1047
1048    // Cast to the access type.
1049    const llvm::Type *AccessLTy =
1050      llvm::Type::getIntNTy(getLLVMContext(), AI.AccessWidth);
1051
1052    const llvm::Type *PTy = AccessLTy->getPointerTo(addressSpace);
1053    Ptr = Builder.CreateBitCast(Ptr, PTy);
1054
1055    // Extract the piece of the bit-field value to write in this access, limited
1056    // to the values that are part of this access.
1057    llvm::Value *Val = SrcVal;
1058    if (AI.TargetBitOffset)
1059      Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
1060    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
1061                                                            AI.TargetBitWidth));
1062
1063    // Extend or truncate to the access size.
1064    if (ResSizeInBits < AI.AccessWidth)
1065      Val = Builder.CreateZExt(Val, AccessLTy);
1066    else if (ResSizeInBits > AI.AccessWidth)
1067      Val = Builder.CreateTrunc(Val, AccessLTy);
1068
1069    // Shift into the position in memory.
1070    if (AI.FieldBitStart)
1071      Val = Builder.CreateShl(Val, AI.FieldBitStart);
1072
1073    // If necessary, load and OR in bits that are outside of the bit-field.
1074    if (AI.TargetBitWidth != AI.AccessWidth) {
1075      llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
1076      if (!AI.AccessAlignment.isZero())
1077        Load->setAlignment(AI.AccessAlignment.getQuantity());
1078
1079      // Compute the mask for zeroing the bits that are part of the bit-field.
1080      llvm::APInt InvMask =
1081        ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
1082                                 AI.FieldBitStart + AI.TargetBitWidth);
1083
1084      // Apply the mask and OR in to the value to write.
1085      Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
1086    }
1087
1088    // Write the value.
1089    llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
1090                                                 Dst.isVolatileQualified());
1091    if (!AI.AccessAlignment.isZero())
1092      Store->setAlignment(AI.AccessAlignment.getQuantity());
1093  }
1094}
1095
1096void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
1097                                                               LValue Dst,
1098                                                               QualType Ty) {
1099  // This access turns into a read/modify/write of the vector.  Load the input
1100  // value now.
1101  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
1102                                        Dst.isVolatileQualified(), "tmp");
1103  const llvm::Constant *Elts = Dst.getExtVectorElts();
1104
1105  llvm::Value *SrcVal = Src.getScalarVal();
1106
1107  if (const VectorType *VTy = Ty->getAs<VectorType>()) {
1108    unsigned NumSrcElts = VTy->getNumElements();
1109    unsigned NumDstElts =
1110       cast<llvm::VectorType>(Vec->getType())->getNumElements();
1111    if (NumDstElts == NumSrcElts) {
1112      // Use shuffle vector is the src and destination are the same number of
1113      // elements and restore the vector mask since it is on the side it will be
1114      // stored.
1115      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
1116      for (unsigned i = 0; i != NumSrcElts; ++i) {
1117        unsigned InIdx = getAccessedFieldNo(i, Elts);
1118        Mask[InIdx] = llvm::ConstantInt::get(Int32Ty, i);
1119      }
1120
1121      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1122      Vec = Builder.CreateShuffleVector(SrcVal,
1123                                        llvm::UndefValue::get(Vec->getType()),
1124                                        MaskV, "tmp");
1125    } else if (NumDstElts > NumSrcElts) {
1126      // Extended the source vector to the same length and then shuffle it
1127      // into the destination.
1128      // FIXME: since we're shuffling with undef, can we just use the indices
1129      //        into that?  This could be simpler.
1130      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
1131      unsigned i;
1132      for (i = 0; i != NumSrcElts; ++i)
1133        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1134      for (; i != NumDstElts; ++i)
1135        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
1136      llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
1137      llvm::Value *ExtSrcVal =
1138        Builder.CreateShuffleVector(SrcVal,
1139                                    llvm::UndefValue::get(SrcVal->getType()),
1140                                    ExtMaskV, "tmp");
1141      // build identity
1142      llvm::SmallVector<llvm::Constant*, 4> Mask;
1143      for (unsigned i = 0; i != NumDstElts; ++i)
1144        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1145
1146      // modify when what gets shuffled in
1147      for (unsigned i = 0; i != NumSrcElts; ++i) {
1148        unsigned Idx = getAccessedFieldNo(i, Elts);
1149        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
1150      }
1151      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1152      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
1153    } else {
1154      // We should never shorten the vector
1155      assert(0 && "unexpected shorten vector length");
1156    }
1157  } else {
1158    // If the Src is a scalar (not a vector) it must be updating one element.
1159    unsigned InIdx = getAccessedFieldNo(0, Elts);
1160    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1161    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
1162  }
1163
1164  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1165}
1166
1167// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1168// generating write-barries API. It is currently a global, ivar,
1169// or neither.
1170static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1171                                 LValue &LV) {
1172  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
1173    return;
1174
1175  if (isa<ObjCIvarRefExpr>(E)) {
1176    LV.setObjCIvar(true);
1177    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1178    LV.setBaseIvarExp(Exp->getBase());
1179    LV.setObjCArray(E->getType()->isArrayType());
1180    return;
1181  }
1182
1183  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1184    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1185      if (VD->hasGlobalStorage()) {
1186        LV.setGlobalObjCRef(true);
1187        LV.setThreadLocalRef(VD->isThreadSpecified());
1188      }
1189    }
1190    LV.setObjCArray(E->getType()->isArrayType());
1191    return;
1192  }
1193
1194  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1195    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1196    return;
1197  }
1198
1199  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1200    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1201    if (LV.isObjCIvar()) {
1202      // If cast is to a structure pointer, follow gcc's behavior and make it
1203      // a non-ivar write-barrier.
1204      QualType ExpTy = E->getType();
1205      if (ExpTy->isPointerType())
1206        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1207      if (ExpTy->isRecordType())
1208        LV.setObjCIvar(false);
1209    }
1210    return;
1211  }
1212
1213  if (const GenericSelectionExpr *Exp = dyn_cast<GenericSelectionExpr>(E)) {
1214    setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
1215    return;
1216  }
1217
1218  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1219    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1220    return;
1221  }
1222
1223  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1224    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1225    return;
1226  }
1227
1228  if (const ObjCBridgedCastExpr *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
1229    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1230    return;
1231  }
1232
1233  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1234    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1235    if (LV.isObjCIvar() && !LV.isObjCArray())
1236      // Using array syntax to assigning to what an ivar points to is not
1237      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1238      LV.setObjCIvar(false);
1239    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1240      // Using array syntax to assigning to what global points to is not
1241      // same as assigning to the global itself. {id *G;} G[i] = 0;
1242      LV.setGlobalObjCRef(false);
1243    return;
1244  }
1245
1246  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1247    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1248    // We don't know if member is an 'ivar', but this flag is looked at
1249    // only in the context of LV.isObjCIvar().
1250    LV.setObjCArray(E->getType()->isArrayType());
1251    return;
1252  }
1253}
1254
1255static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1256                                      const Expr *E, const VarDecl *VD) {
1257  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1258         "Var decl must have external storage or be a file var decl!");
1259
1260  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1261  if (VD->getType()->isReferenceType())
1262    V = CGF.Builder.CreateLoad(V, "tmp");
1263  unsigned Alignment = CGF.getContext().getDeclAlign(VD).getQuantity();
1264  LValue LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1265  setObjCGCLValueClass(CGF.getContext(), E, LV);
1266  return LV;
1267}
1268
1269static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1270                                      const Expr *E, const FunctionDecl *FD) {
1271  llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1272  if (!FD->hasPrototype()) {
1273    if (const FunctionProtoType *Proto =
1274            FD->getType()->getAs<FunctionProtoType>()) {
1275      // Ugly case: for a K&R-style definition, the type of the definition
1276      // isn't the same as the type of a use.  Correct for this with a
1277      // bitcast.
1278      QualType NoProtoType =
1279          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1280      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1281      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1282    }
1283  }
1284  unsigned Alignment = CGF.getContext().getDeclAlign(FD).getQuantity();
1285  return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1286}
1287
1288LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1289  const NamedDecl *ND = E->getDecl();
1290  unsigned Alignment = getContext().getDeclAlign(ND).getQuantity();
1291
1292  if (ND->hasAttr<WeakRefAttr>()) {
1293    const ValueDecl *VD = cast<ValueDecl>(ND);
1294    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1295    return MakeAddrLValue(Aliasee, E->getType(), Alignment);
1296  }
1297
1298  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1299
1300    // Check if this is a global variable.
1301    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1302      return EmitGlobalVarDeclLValue(*this, E, VD);
1303
1304    bool NonGCable = VD->hasLocalStorage() &&
1305                     !VD->getType()->isReferenceType() &&
1306                     !VD->hasAttr<BlocksAttr>();
1307
1308    llvm::Value *V = LocalDeclMap[VD];
1309    if (!V && VD->isStaticLocal())
1310      V = CGM.getStaticLocalDeclAddress(VD);
1311    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1312
1313    if (VD->hasAttr<BlocksAttr>())
1314      V = BuildBlockByrefAddress(V, VD);
1315
1316    if (VD->getType()->isReferenceType())
1317      V = Builder.CreateLoad(V, "tmp");
1318
1319    LValue LV = MakeAddrLValue(V, E->getType(), Alignment);
1320    if (NonGCable) {
1321      LV.getQuals().removeObjCGCAttr();
1322      LV.setNonGC(true);
1323    }
1324    setObjCGCLValueClass(getContext(), E, LV);
1325    return LV;
1326  }
1327
1328  if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
1329    return EmitFunctionDeclLValue(*this, E, fn);
1330
1331  assert(false && "Unhandled DeclRefExpr");
1332
1333  // an invalid LValue, but the assert will
1334  // ensure that this point is never reached.
1335  return LValue();
1336}
1337
1338LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1339  unsigned Alignment =
1340    getContext().getDeclAlign(E->getDecl()).getQuantity();
1341  return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
1342}
1343
1344LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1345  // __extension__ doesn't affect lvalue-ness.
1346  if (E->getOpcode() == UO_Extension)
1347    return EmitLValue(E->getSubExpr());
1348
1349  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1350  switch (E->getOpcode()) {
1351  default: assert(0 && "Unknown unary operator lvalue!");
1352  case UO_Deref: {
1353    QualType T = E->getSubExpr()->getType()->getPointeeType();
1354    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1355
1356    LValue LV = MakeAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1357    LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1358
1359    // We should not generate __weak write barrier on indirect reference
1360    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1361    // But, we continue to generate __strong write barrier on indirect write
1362    // into a pointer to object.
1363    if (getContext().getLangOptions().ObjC1 &&
1364        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1365        LV.isObjCWeak())
1366      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1367    return LV;
1368  }
1369  case UO_Real:
1370  case UO_Imag: {
1371    LValue LV = EmitLValue(E->getSubExpr());
1372    assert(LV.isSimple() && "real/imag on non-ordinary l-value");
1373    llvm::Value *Addr = LV.getAddress();
1374
1375    // real and imag are valid on scalars.  This is a faster way of
1376    // testing that.
1377    if (!cast<llvm::PointerType>(Addr->getType())
1378           ->getElementType()->isStructTy()) {
1379      assert(E->getSubExpr()->getType()->isArithmeticType());
1380      return LV;
1381    }
1382
1383    assert(E->getSubExpr()->getType()->isAnyComplexType());
1384
1385    unsigned Idx = E->getOpcode() == UO_Imag;
1386    return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1387                                                  Idx, "idx"),
1388                          ExprTy);
1389  }
1390  case UO_PreInc:
1391  case UO_PreDec: {
1392    LValue LV = EmitLValue(E->getSubExpr());
1393    bool isInc = E->getOpcode() == UO_PreInc;
1394
1395    if (E->getType()->isAnyComplexType())
1396      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1397    else
1398      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1399    return LV;
1400  }
1401  }
1402}
1403
1404LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1405  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1406                        E->getType());
1407}
1408
1409LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1410  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1411                        E->getType());
1412}
1413
1414
1415LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1416  switch (E->getIdentType()) {
1417  default:
1418    return EmitUnsupportedLValue(E, "predefined expression");
1419
1420  case PredefinedExpr::Func:
1421  case PredefinedExpr::Function:
1422  case PredefinedExpr::PrettyFunction: {
1423    unsigned Type = E->getIdentType();
1424    std::string GlobalVarName;
1425
1426    switch (Type) {
1427    default: assert(0 && "Invalid type");
1428    case PredefinedExpr::Func:
1429      GlobalVarName = "__func__.";
1430      break;
1431    case PredefinedExpr::Function:
1432      GlobalVarName = "__FUNCTION__.";
1433      break;
1434    case PredefinedExpr::PrettyFunction:
1435      GlobalVarName = "__PRETTY_FUNCTION__.";
1436      break;
1437    }
1438
1439    llvm::StringRef FnName = CurFn->getName();
1440    if (FnName.startswith("\01"))
1441      FnName = FnName.substr(1);
1442    GlobalVarName += FnName;
1443
1444    const Decl *CurDecl = CurCodeDecl;
1445    if (CurDecl == 0)
1446      CurDecl = getContext().getTranslationUnitDecl();
1447
1448    std::string FunctionName =
1449        (isa<BlockDecl>(CurDecl)
1450         ? FnName.str()
1451         : PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl));
1452
1453    llvm::Constant *C =
1454      CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1455    return MakeAddrLValue(C, E->getType());
1456  }
1457  }
1458}
1459
1460llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1461  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1462
1463  // If we are not optimzing, don't collapse all calls to trap in the function
1464  // to the same call, that way, in the debugger they can see which operation
1465  // did in fact fail.  If we are optimizing, we collapse all calls to trap down
1466  // to just one per function to save on codesize.
1467  if (GCO.OptimizationLevel && TrapBB)
1468    return TrapBB;
1469
1470  llvm::BasicBlock *Cont = 0;
1471  if (HaveInsertPoint()) {
1472    Cont = createBasicBlock("cont");
1473    EmitBranch(Cont);
1474  }
1475  TrapBB = createBasicBlock("trap");
1476  EmitBlock(TrapBB);
1477
1478  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap, 0, 0);
1479  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1480  TrapCall->setDoesNotReturn();
1481  TrapCall->setDoesNotThrow();
1482  Builder.CreateUnreachable();
1483
1484  if (Cont)
1485    EmitBlock(Cont);
1486  return TrapBB;
1487}
1488
1489/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
1490/// array to pointer, return the array subexpression.
1491static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
1492  // If this isn't just an array->pointer decay, bail out.
1493  const CastExpr *CE = dyn_cast<CastExpr>(E);
1494  if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
1495    return 0;
1496
1497  // If this is a decay from variable width array, bail out.
1498  const Expr *SubExpr = CE->getSubExpr();
1499  if (SubExpr->getType()->isVariableArrayType())
1500    return 0;
1501
1502  return SubExpr;
1503}
1504
1505LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1506  // The index must always be an integer, which is not an aggregate.  Emit it.
1507  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1508  QualType IdxTy  = E->getIdx()->getType();
1509  bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
1510
1511  // If the base is a vector type, then we are forming a vector element lvalue
1512  // with this subscript.
1513  if (E->getBase()->getType()->isVectorType()) {
1514    // Emit the vector as an lvalue to get its address.
1515    LValue LHS = EmitLValue(E->getBase());
1516    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1517    Idx = Builder.CreateIntCast(Idx, Int32Ty, IdxSigned, "vidx");
1518    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1519                                 E->getBase()->getType());
1520  }
1521
1522  // Extend or truncate the index type to 32 or 64-bits.
1523  if (Idx->getType() != IntPtrTy)
1524    Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
1525
1526  // FIXME: As llvm implements the object size checking, this can come out.
1527  if (CatchUndefined) {
1528    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())){
1529      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1530        if (ICE->getCastKind() == CK_ArrayToPointerDecay) {
1531          if (const ConstantArrayType *CAT
1532              = getContext().getAsConstantArrayType(DRE->getType())) {
1533            llvm::APInt Size = CAT->getSize();
1534            llvm::BasicBlock *Cont = createBasicBlock("cont");
1535            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1536                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1537                                 Cont, getTrapBB());
1538            EmitBlock(Cont);
1539          }
1540        }
1541      }
1542    }
1543  }
1544
1545  // We know that the pointer points to a type of the correct size, unless the
1546  // size is a VLA or Objective-C interface.
1547  llvm::Value *Address = 0;
1548  unsigned ArrayAlignment = 0;
1549  if (const VariableArrayType *VAT =
1550        getContext().getAsVariableArrayType(E->getType())) {
1551    llvm::Value *VLASize = GetVLASize(VAT);
1552
1553    Idx = Builder.CreateMul(Idx, VLASize);
1554
1555    // The base must be a pointer, which is not an aggregate.  Emit it.
1556    llvm::Value *Base = EmitScalarExpr(E->getBase());
1557
1558    Address = EmitCastToVoidPtr(Base);
1559    if (getContext().getLangOptions().isSignedOverflowDefined())
1560      Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1561    else
1562      Address = Builder.CreateInBoundsGEP(Address, Idx, "arrayidx");
1563    Address = Builder.CreateBitCast(Address, Base->getType());
1564  } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
1565    // Indexing over an interface, as in "NSString *P; P[4];"
1566    llvm::Value *InterfaceSize =
1567      llvm::ConstantInt::get(Idx->getType(),
1568          getContext().getTypeSizeInChars(OIT).getQuantity());
1569
1570    Idx = Builder.CreateMul(Idx, InterfaceSize);
1571
1572    // The base must be a pointer, which is not an aggregate.  Emit it.
1573    llvm::Value *Base = EmitScalarExpr(E->getBase());
1574    Address = EmitCastToVoidPtr(Base);
1575    Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1576    Address = Builder.CreateBitCast(Address, Base->getType());
1577  } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
1578    // If this is A[i] where A is an array, the frontend will have decayed the
1579    // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
1580    // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
1581    // "gep x, i" here.  Emit one "gep A, 0, i".
1582    assert(Array->getType()->isArrayType() &&
1583           "Array to pointer decay must have array source type!");
1584    LValue ArrayLV = EmitLValue(Array);
1585    llvm::Value *ArrayPtr = ArrayLV.getAddress();
1586    llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
1587    llvm::Value *Args[] = { Zero, Idx };
1588
1589    // Propagate the alignment from the array itself to the result.
1590    ArrayAlignment = ArrayLV.getAlignment();
1591
1592    if (getContext().getLangOptions().isSignedOverflowDefined())
1593      Address = Builder.CreateGEP(ArrayPtr, Args, Args+2, "arrayidx");
1594    else
1595      Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, Args+2, "arrayidx");
1596  } else {
1597    // The base must be a pointer, which is not an aggregate.  Emit it.
1598    llvm::Value *Base = EmitScalarExpr(E->getBase());
1599    if (getContext().getLangOptions().isSignedOverflowDefined())
1600      Address = Builder.CreateGEP(Base, Idx, "arrayidx");
1601    else
1602      Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1603  }
1604
1605  QualType T = E->getBase()->getType()->getPointeeType();
1606  assert(!T.isNull() &&
1607         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1608
1609  // Limit the alignment to that of the result type.
1610  if (ArrayAlignment) {
1611    unsigned Align = getContext().getTypeAlignInChars(T).getQuantity();
1612    ArrayAlignment = std::min(Align, ArrayAlignment);
1613  }
1614
1615  LValue LV = MakeAddrLValue(Address, T, ArrayAlignment);
1616  LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
1617
1618  if (getContext().getLangOptions().ObjC1 &&
1619      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1620    LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1621    setObjCGCLValueClass(getContext(), E, LV);
1622  }
1623  return LV;
1624}
1625
1626static
1627llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1628                                       llvm::SmallVector<unsigned, 4> &Elts) {
1629  llvm::SmallVector<llvm::Constant*, 4> CElts;
1630
1631  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1632  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1633    CElts.push_back(llvm::ConstantInt::get(Int32Ty, Elts[i]));
1634
1635  return llvm::ConstantVector::get(CElts);
1636}
1637
1638LValue CodeGenFunction::
1639EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1640  // Emit the base vector as an l-value.
1641  LValue Base;
1642
1643  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1644  if (E->isArrow()) {
1645    // If it is a pointer to a vector, emit the address and form an lvalue with
1646    // it.
1647    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1648    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1649    Base = MakeAddrLValue(Ptr, PT->getPointeeType());
1650    Base.getQuals().removeObjCGCAttr();
1651  } else if (E->getBase()->isGLValue()) {
1652    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1653    // emit the base as an lvalue.
1654    assert(E->getBase()->getType()->isVectorType());
1655    Base = EmitLValue(E->getBase());
1656  } else {
1657    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1658    assert(E->getBase()->getType()->isVectorType() &&
1659           "Result must be a vector");
1660    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1661
1662    // Store the vector to memory (because LValue wants an address).
1663    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1664    Builder.CreateStore(Vec, VecMem);
1665    Base = MakeAddrLValue(VecMem, E->getBase()->getType());
1666  }
1667
1668  QualType type =
1669    E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers());
1670
1671  // Encode the element access list into a vector of unsigned indices.
1672  llvm::SmallVector<unsigned, 4> Indices;
1673  E->getEncodedElementAccess(Indices);
1674
1675  if (Base.isSimple()) {
1676    llvm::Constant *CV = GenerateConstantVector(getLLVMContext(), Indices);
1677    return LValue::MakeExtVectorElt(Base.getAddress(), CV, type);
1678  }
1679  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1680
1681  llvm::Constant *BaseElts = Base.getExtVectorElts();
1682  llvm::SmallVector<llvm::Constant *, 4> CElts;
1683
1684  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1685    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1686      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1687    else
1688      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1689  }
1690  llvm::Constant *CV = llvm::ConstantVector::get(CElts);
1691  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV, type);
1692}
1693
1694LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1695  bool isNonGC = false;
1696  Expr *BaseExpr = E->getBase();
1697  llvm::Value *BaseValue = NULL;
1698  Qualifiers BaseQuals;
1699
1700  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1701  if (E->isArrow()) {
1702    BaseValue = EmitScalarExpr(BaseExpr);
1703    const PointerType *PTy =
1704      BaseExpr->getType()->getAs<PointerType>();
1705    BaseQuals = PTy->getPointeeType().getQualifiers();
1706  } else {
1707    LValue BaseLV = EmitLValue(BaseExpr);
1708    if (BaseLV.isNonGC())
1709      isNonGC = true;
1710    // FIXME: this isn't right for bitfields.
1711    BaseValue = BaseLV.getAddress();
1712    QualType BaseTy = BaseExpr->getType();
1713    BaseQuals = BaseTy.getQualifiers();
1714  }
1715
1716  NamedDecl *ND = E->getMemberDecl();
1717  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1718    LValue LV = EmitLValueForField(BaseValue, Field,
1719                                   BaseQuals.getCVRQualifiers());
1720    LV.setNonGC(isNonGC);
1721    setObjCGCLValueClass(getContext(), E, LV);
1722    return LV;
1723  }
1724
1725  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1726    return EmitGlobalVarDeclLValue(*this, E, VD);
1727
1728  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1729    return EmitFunctionDeclLValue(*this, E, FD);
1730
1731  assert(false && "Unhandled member declaration!");
1732  return LValue();
1733}
1734
1735LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
1736                                              const FieldDecl *Field,
1737                                              unsigned CVRQualifiers) {
1738  const CGRecordLayout &RL =
1739    CGM.getTypes().getCGRecordLayout(Field->getParent());
1740  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1741  return LValue::MakeBitfield(BaseValue, Info,
1742                          Field->getType().withCVRQualifiers(CVRQualifiers));
1743}
1744
1745/// EmitLValueForAnonRecordField - Given that the field is a member of
1746/// an anonymous struct or union buried inside a record, and given
1747/// that the base value is a pointer to the enclosing record, derive
1748/// an lvalue for the ultimate field.
1749LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
1750                                             const IndirectFieldDecl *Field,
1751                                                     unsigned CVRQualifiers) {
1752  IndirectFieldDecl::chain_iterator I = Field->chain_begin(),
1753    IEnd = Field->chain_end();
1754  while (true) {
1755    LValue LV = EmitLValueForField(BaseValue, cast<FieldDecl>(*I),
1756                                   CVRQualifiers);
1757    if (++I == IEnd) return LV;
1758
1759    assert(LV.isSimple());
1760    BaseValue = LV.getAddress();
1761    CVRQualifiers |= LV.getVRQualifiers();
1762  }
1763}
1764
1765LValue CodeGenFunction::EmitLValueForField(llvm::Value *baseAddr,
1766                                           const FieldDecl *field,
1767                                           unsigned cvr) {
1768  if (field->isBitField())
1769    return EmitLValueForBitfield(baseAddr, field, cvr);
1770
1771  const RecordDecl *rec = field->getParent();
1772  QualType type = field->getType();
1773
1774  bool mayAlias = rec->hasAttr<MayAliasAttr>();
1775
1776  llvm::Value *addr;
1777  if (rec->isUnion()) {
1778    // For unions, we just cast to the appropriate type.
1779    assert(!type->isReferenceType() && "union has reference member");
1780
1781    const llvm::Type *llvmType = CGM.getTypes().ConvertTypeForMem(type);
1782    unsigned AS =
1783      cast<llvm::PointerType>(baseAddr->getType())->getAddressSpace();
1784    addr = Builder.CreateBitCast(baseAddr, llvmType->getPointerTo(AS),
1785                                 field->getName());
1786  } else {
1787    // For structs, we GEP to the field that the record layout suggests.
1788    unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
1789    addr = Builder.CreateStructGEP(baseAddr, idx, field->getName());
1790
1791    // If this is a reference field, load the reference right now.
1792    if (const ReferenceType *refType = type->getAs<ReferenceType>()) {
1793      llvm::LoadInst *load = Builder.CreateLoad(addr, "ref");
1794      if (cvr & Qualifiers::Volatile) load->setVolatile(true);
1795
1796      if (CGM.shouldUseTBAA()) {
1797        llvm::MDNode *tbaa;
1798        if (mayAlias)
1799          tbaa = CGM.getTBAAInfo(getContext().CharTy);
1800        else
1801          tbaa = CGM.getTBAAInfo(type);
1802        CGM.DecorateInstruction(load, tbaa);
1803      }
1804
1805      addr = load;
1806      mayAlias = false;
1807      type = refType->getPointeeType();
1808      cvr = 0; // qualifiers don't recursively apply to referencee
1809    }
1810  }
1811
1812  unsigned alignment = getContext().getDeclAlign(field).getQuantity();
1813  LValue LV = MakeAddrLValue(addr, type, alignment);
1814  LV.getQuals().addCVRQualifiers(cvr);
1815
1816  // __weak attribute on a field is ignored.
1817  if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
1818    LV.getQuals().removeObjCGCAttr();
1819
1820  // Fields of may_alias structs act like 'char' for TBAA purposes.
1821  // FIXME: this should get propagated down through anonymous structs
1822  // and unions.
1823  if (mayAlias && LV.getTBAAInfo())
1824    LV.setTBAAInfo(CGM.getTBAAInfo(getContext().CharTy));
1825
1826  return LV;
1827}
1828
1829LValue
1830CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value *BaseValue,
1831                                                  const FieldDecl *Field,
1832                                                  unsigned CVRQualifiers) {
1833  QualType FieldType = Field->getType();
1834
1835  if (!FieldType->isReferenceType())
1836    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1837
1838  const CGRecordLayout &RL =
1839    CGM.getTypes().getCGRecordLayout(Field->getParent());
1840  unsigned idx = RL.getLLVMFieldNo(Field);
1841  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1842
1843  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1844
1845  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1846  return MakeAddrLValue(V, FieldType, Alignment);
1847}
1848
1849LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
1850  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1851  const Expr *InitExpr = E->getInitializer();
1852  LValue Result = MakeAddrLValue(DeclPtr, E->getType());
1853
1854  EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
1855                   /*Init*/ true);
1856
1857  return Result;
1858}
1859
1860LValue CodeGenFunction::
1861EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
1862  if (!expr->isGLValue()) {
1863    // ?: here should be an aggregate.
1864    assert((hasAggregateLLVMType(expr->getType()) &&
1865            !expr->getType()->isAnyComplexType()) &&
1866           "Unexpected conditional operator!");
1867    return EmitAggExprToLValue(expr);
1868  }
1869
1870  const Expr *condExpr = expr->getCond();
1871  bool CondExprBool;
1872  if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
1873    const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr();
1874    if (!CondExprBool) std::swap(live, dead);
1875
1876    if (!ContainsLabel(dead))
1877      return EmitLValue(live);
1878  }
1879
1880  OpaqueValueMapping binding(*this, expr);
1881
1882  llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
1883  llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
1884  llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
1885
1886  ConditionalEvaluation eval(*this);
1887  EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock);
1888
1889  // Any temporaries created here are conditional.
1890  EmitBlock(lhsBlock);
1891  eval.begin(*this);
1892  LValue lhs = EmitLValue(expr->getTrueExpr());
1893  eval.end(*this);
1894
1895  if (!lhs.isSimple())
1896    return EmitUnsupportedLValue(expr, "conditional operator");
1897
1898  lhsBlock = Builder.GetInsertBlock();
1899  Builder.CreateBr(contBlock);
1900
1901  // Any temporaries created here are conditional.
1902  EmitBlock(rhsBlock);
1903  eval.begin(*this);
1904  LValue rhs = EmitLValue(expr->getFalseExpr());
1905  eval.end(*this);
1906  if (!rhs.isSimple())
1907    return EmitUnsupportedLValue(expr, "conditional operator");
1908  rhsBlock = Builder.GetInsertBlock();
1909
1910  EmitBlock(contBlock);
1911
1912  llvm::PHINode *phi = Builder.CreatePHI(lhs.getAddress()->getType(), 2,
1913                                         "cond-lvalue");
1914  phi->addIncoming(lhs.getAddress(), lhsBlock);
1915  phi->addIncoming(rhs.getAddress(), rhsBlock);
1916  return MakeAddrLValue(phi, expr->getType());
1917}
1918
1919/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1920/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1921/// otherwise if a cast is needed by the code generator in an lvalue context,
1922/// then it must mean that we need the address of an aggregate in order to
1923/// access one of its fields.  This can happen for all the reasons that casts
1924/// are permitted with aggregate result, including noop aggregate casts, and
1925/// cast from scalar to union.
1926LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1927  switch (E->getCastKind()) {
1928  case CK_ToVoid:
1929    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1930
1931  case CK_Dependent:
1932    llvm_unreachable("dependent cast kind in IR gen!");
1933
1934  case CK_GetObjCProperty: {
1935    LValue LV = EmitLValue(E->getSubExpr());
1936    assert(LV.isPropertyRef());
1937    RValue RV = EmitLoadOfPropertyRefLValue(LV);
1938
1939    // Property is an aggregate r-value.
1940    if (RV.isAggregate()) {
1941      return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
1942    }
1943
1944    // Implicit property returns an l-value.
1945    assert(RV.isScalar());
1946    return MakeAddrLValue(RV.getScalarVal(), E->getSubExpr()->getType());
1947  }
1948
1949  case CK_NoOp:
1950  case CK_LValueToRValue:
1951    if (!E->getSubExpr()->Classify(getContext()).isPRValue()
1952        || E->getType()->isRecordType())
1953      return EmitLValue(E->getSubExpr());
1954    // Fall through to synthesize a temporary.
1955
1956  case CK_BitCast:
1957  case CK_ArrayToPointerDecay:
1958  case CK_FunctionToPointerDecay:
1959  case CK_NullToMemberPointer:
1960  case CK_NullToPointer:
1961  case CK_IntegralToPointer:
1962  case CK_PointerToIntegral:
1963  case CK_PointerToBoolean:
1964  case CK_VectorSplat:
1965  case CK_IntegralCast:
1966  case CK_IntegralToBoolean:
1967  case CK_IntegralToFloating:
1968  case CK_FloatingToIntegral:
1969  case CK_FloatingToBoolean:
1970  case CK_FloatingCast:
1971  case CK_FloatingRealToComplex:
1972  case CK_FloatingComplexToReal:
1973  case CK_FloatingComplexToBoolean:
1974  case CK_FloatingComplexCast:
1975  case CK_FloatingComplexToIntegralComplex:
1976  case CK_IntegralRealToComplex:
1977  case CK_IntegralComplexToReal:
1978  case CK_IntegralComplexToBoolean:
1979  case CK_IntegralComplexCast:
1980  case CK_IntegralComplexToFloatingComplex:
1981  case CK_DerivedToBaseMemberPointer:
1982  case CK_BaseToDerivedMemberPointer:
1983  case CK_MemberPointerToBoolean:
1984  case CK_AnyPointerToBlockPointerCast:
1985  case CK_ObjCProduceObject:
1986  case CK_ObjCConsumeObject: {
1987    // These casts only produce lvalues when we're binding a reference to a
1988    // temporary realized from a (converted) pure rvalue. Emit the expression
1989    // as a value, copy it into a temporary, and return an lvalue referring to
1990    // that temporary.
1991    llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
1992    EmitAnyExprToMem(E, V, E->getType().getQualifiers(), false);
1993    return MakeAddrLValue(V, E->getType());
1994  }
1995
1996  case CK_Dynamic: {
1997    LValue LV = EmitLValue(E->getSubExpr());
1998    llvm::Value *V = LV.getAddress();
1999    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
2000    return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
2001  }
2002
2003  case CK_ConstructorConversion:
2004  case CK_UserDefinedConversion:
2005  case CK_AnyPointerToObjCPointerCast:
2006    return EmitLValue(E->getSubExpr());
2007
2008  case CK_UncheckedDerivedToBase:
2009  case CK_DerivedToBase: {
2010    const RecordType *DerivedClassTy =
2011      E->getSubExpr()->getType()->getAs<RecordType>();
2012    CXXRecordDecl *DerivedClassDecl =
2013      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2014
2015    LValue LV = EmitLValue(E->getSubExpr());
2016    llvm::Value *This = LV.getAddress();
2017
2018    // Perform the derived-to-base conversion
2019    llvm::Value *Base =
2020      GetAddressOfBaseClass(This, DerivedClassDecl,
2021                            E->path_begin(), E->path_end(),
2022                            /*NullCheckValue=*/false);
2023
2024    return MakeAddrLValue(Base, E->getType());
2025  }
2026  case CK_ToUnion:
2027    return EmitAggExprToLValue(E);
2028  case CK_BaseToDerived: {
2029    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
2030    CXXRecordDecl *DerivedClassDecl =
2031      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2032
2033    LValue LV = EmitLValue(E->getSubExpr());
2034
2035    // Perform the base-to-derived conversion
2036    llvm::Value *Derived =
2037      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
2038                               E->path_begin(), E->path_end(),
2039                               /*NullCheckValue=*/false);
2040
2041    return MakeAddrLValue(Derived, E->getType());
2042  }
2043  case CK_LValueBitCast: {
2044    // This must be a reinterpret_cast (or c-style equivalent).
2045    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
2046
2047    LValue LV = EmitLValue(E->getSubExpr());
2048    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2049                                           ConvertType(CE->getTypeAsWritten()));
2050    return MakeAddrLValue(V, E->getType());
2051  }
2052  case CK_ObjCObjectLValueCast: {
2053    LValue LV = EmitLValue(E->getSubExpr());
2054    QualType ToType = getContext().getLValueReferenceType(E->getType());
2055    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2056                                           ConvertType(ToType));
2057    return MakeAddrLValue(V, E->getType());
2058  }
2059  }
2060
2061  llvm_unreachable("Unhandled lvalue cast kind?");
2062}
2063
2064LValue CodeGenFunction::EmitNullInitializationLValue(
2065                                              const CXXScalarValueInitExpr *E) {
2066  QualType Ty = E->getType();
2067  LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
2068  EmitNullInitialization(LV.getAddress(), Ty);
2069  return LV;
2070}
2071
2072LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
2073  assert(e->isGLValue() || e->getType()->isRecordType());
2074  return getOpaqueLValueMapping(e);
2075}
2076
2077LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
2078                                           const MaterializeTemporaryExpr *E) {
2079  RValue RV = EmitReferenceBindingToExpr(E->GetTemporaryExpr(),
2080                                         /*InitializedDecl=*/0);
2081  return LValue::MakeAddr(RV.getScalarVal(), E->getType(),
2082                          CGM.getContext().getTypeAlign(E->getType()),
2083                          CGM.getContext());
2084}
2085
2086
2087//===--------------------------------------------------------------------===//
2088//                             Expression Emission
2089//===--------------------------------------------------------------------===//
2090
2091RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
2092                                     ReturnValueSlot ReturnValue) {
2093  if (CGDebugInfo *DI = getDebugInfo()) {
2094    DI->setLocation(E->getLocStart());
2095    DI->UpdateLineDirectiveRegion(Builder);
2096    DI->EmitStopPoint(Builder);
2097  }
2098
2099  // Builtins never have block type.
2100  if (E->getCallee()->getType()->isBlockPointerType())
2101    return EmitBlockCallExpr(E, ReturnValue);
2102
2103  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
2104    return EmitCXXMemberCallExpr(CE, ReturnValue);
2105
2106  const Decl *TargetDecl = 0;
2107  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
2108    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
2109      TargetDecl = DRE->getDecl();
2110      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
2111        if (unsigned builtinID = FD->getBuiltinID())
2112          return EmitBuiltinExpr(FD, builtinID, E);
2113    }
2114  }
2115
2116  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
2117    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
2118      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
2119
2120  if (const CXXPseudoDestructorExpr *PseudoDtor
2121          = dyn_cast<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
2122    QualType DestroyedType = PseudoDtor->getDestroyedType();
2123    if (getContext().getLangOptions().ObjCAutoRefCount &&
2124        DestroyedType->isObjCLifetimeType() &&
2125        (DestroyedType.getObjCLifetime() == Qualifiers::OCL_Strong ||
2126         DestroyedType.getObjCLifetime() == Qualifiers::OCL_Weak)) {
2127      // Automatic Reference Counting:
2128      //   If the pseudo-expression names a retainable object with weak or
2129      //   strong lifetime, the object shall be released.
2130      Expr *BaseExpr = PseudoDtor->getBase();
2131      llvm::Value *BaseValue = NULL;
2132      Qualifiers BaseQuals;
2133
2134      // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
2135      if (PseudoDtor->isArrow()) {
2136        BaseValue = EmitScalarExpr(BaseExpr);
2137        const PointerType *PTy = BaseExpr->getType()->getAs<PointerType>();
2138        BaseQuals = PTy->getPointeeType().getQualifiers();
2139      } else {
2140        LValue BaseLV = EmitLValue(BaseExpr);
2141        BaseValue = BaseLV.getAddress();
2142        QualType BaseTy = BaseExpr->getType();
2143        BaseQuals = BaseTy.getQualifiers();
2144      }
2145
2146      switch (PseudoDtor->getDestroyedType().getObjCLifetime()) {
2147      case Qualifiers::OCL_None:
2148      case Qualifiers::OCL_ExplicitNone:
2149      case Qualifiers::OCL_Autoreleasing:
2150        break;
2151
2152      case Qualifiers::OCL_Strong:
2153        EmitARCRelease(Builder.CreateLoad(BaseValue,
2154                          PseudoDtor->getDestroyedType().isVolatileQualified()),
2155                       /*precise*/ true);
2156        break;
2157
2158      case Qualifiers::OCL_Weak:
2159        EmitARCDestroyWeak(BaseValue);
2160        break;
2161      }
2162    } else {
2163      // C++ [expr.pseudo]p1:
2164      //   The result shall only be used as the operand for the function call
2165      //   operator (), and the result of such a call has type void. The only
2166      //   effect is the evaluation of the postfix-expression before the dot or
2167      //   arrow.
2168      EmitScalarExpr(E->getCallee());
2169    }
2170
2171    return RValue::get(0);
2172  }
2173
2174  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
2175  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
2176                  E->arg_begin(), E->arg_end(), TargetDecl);
2177}
2178
2179LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
2180  // Comma expressions just emit their LHS then their RHS as an l-value.
2181  if (E->getOpcode() == BO_Comma) {
2182    EmitIgnoredExpr(E->getLHS());
2183    EnsureInsertPoint();
2184    return EmitLValue(E->getRHS());
2185  }
2186
2187  if (E->getOpcode() == BO_PtrMemD ||
2188      E->getOpcode() == BO_PtrMemI)
2189    return EmitPointerToDataMemberBinaryExpr(E);
2190
2191  assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
2192
2193  // Note that in all of these cases, __block variables need the RHS
2194  // evaluated first just in case the variable gets moved by the RHS.
2195
2196  if (!hasAggregateLLVMType(E->getType())) {
2197    switch (E->getLHS()->getType().getObjCLifetime()) {
2198    case Qualifiers::OCL_Strong:
2199      return EmitARCStoreStrong(E, /*ignored*/ false).first;
2200
2201    case Qualifiers::OCL_Autoreleasing:
2202      return EmitARCStoreAutoreleasing(E).first;
2203
2204    // No reason to do any of these differently.
2205    case Qualifiers::OCL_None:
2206    case Qualifiers::OCL_ExplicitNone:
2207    case Qualifiers::OCL_Weak:
2208      break;
2209    }
2210
2211    RValue RV = EmitAnyExpr(E->getRHS());
2212    LValue LV = EmitLValue(E->getLHS());
2213    EmitStoreThroughLValue(RV, LV, E->getType());
2214    return LV;
2215  }
2216
2217  if (E->getType()->isAnyComplexType())
2218    return EmitComplexAssignmentLValue(E);
2219
2220  return EmitAggExprToLValue(E);
2221}
2222
2223LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
2224  RValue RV = EmitCallExpr(E);
2225
2226  if (!RV.isScalar())
2227    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2228
2229  assert(E->getCallReturnType()->isReferenceType() &&
2230         "Can't have a scalar return unless the return type is a "
2231         "reference type!");
2232
2233  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2234}
2235
2236LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
2237  // FIXME: This shouldn't require another copy.
2238  return EmitAggExprToLValue(E);
2239}
2240
2241LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
2242  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
2243         && "binding l-value to type which needs a temporary");
2244  AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
2245  EmitCXXConstructExpr(E, Slot);
2246  return MakeAddrLValue(Slot.getAddr(), E->getType());
2247}
2248
2249LValue
2250CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
2251  return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
2252}
2253
2254LValue
2255CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
2256  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
2257  Slot.setLifetimeExternallyManaged();
2258  EmitAggExpr(E->getSubExpr(), Slot);
2259  EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
2260  return MakeAddrLValue(Slot.getAddr(), E->getType());
2261}
2262
2263LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
2264  RValue RV = EmitObjCMessageExpr(E);
2265
2266  if (!RV.isScalar())
2267    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2268
2269  assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
2270         "Can't have a scalar return unless the return type is a "
2271         "reference type!");
2272
2273  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2274}
2275
2276LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
2277  llvm::Value *V =
2278    CGM.getObjCRuntime().GetSelector(Builder, E->getSelector(), true);
2279  return MakeAddrLValue(V, E->getType());
2280}
2281
2282llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
2283                                             const ObjCIvarDecl *Ivar) {
2284  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
2285}
2286
2287LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
2288                                          llvm::Value *BaseValue,
2289                                          const ObjCIvarDecl *Ivar,
2290                                          unsigned CVRQualifiers) {
2291  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
2292                                                   Ivar, CVRQualifiers);
2293}
2294
2295LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
2296  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
2297  llvm::Value *BaseValue = 0;
2298  const Expr *BaseExpr = E->getBase();
2299  Qualifiers BaseQuals;
2300  QualType ObjectTy;
2301  if (E->isArrow()) {
2302    BaseValue = EmitScalarExpr(BaseExpr);
2303    ObjectTy = BaseExpr->getType()->getPointeeType();
2304    BaseQuals = ObjectTy.getQualifiers();
2305  } else {
2306    LValue BaseLV = EmitLValue(BaseExpr);
2307    // FIXME: this isn't right for bitfields.
2308    BaseValue = BaseLV.getAddress();
2309    ObjectTy = BaseExpr->getType();
2310    BaseQuals = ObjectTy.getQualifiers();
2311  }
2312
2313  LValue LV =
2314    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
2315                      BaseQuals.getCVRQualifiers());
2316  setObjCGCLValueClass(getContext(), E, LV);
2317  return LV;
2318}
2319
2320LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
2321  // Can only get l-value for message expression returning aggregate type
2322  RValue RV = EmitAnyExprToTemp(E);
2323  return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2324}
2325
2326RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
2327                                 ReturnValueSlot ReturnValue,
2328                                 CallExpr::const_arg_iterator ArgBeg,
2329                                 CallExpr::const_arg_iterator ArgEnd,
2330                                 const Decl *TargetDecl) {
2331  // Get the actual function type. The callee type will always be a pointer to
2332  // function type or a block pointer type.
2333  assert(CalleeType->isFunctionPointerType() &&
2334         "Call must have function pointer type!");
2335
2336  CalleeType = getContext().getCanonicalType(CalleeType);
2337
2338  const FunctionType *FnType
2339    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
2340
2341  CallArgList Args;
2342  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
2343
2344  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
2345                  Callee, ReturnValue, Args, TargetDecl);
2346}
2347
2348LValue CodeGenFunction::
2349EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
2350  llvm::Value *BaseV;
2351  if (E->getOpcode() == BO_PtrMemI)
2352    BaseV = EmitScalarExpr(E->getLHS());
2353  else
2354    BaseV = EmitLValue(E->getLHS()).getAddress();
2355
2356  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
2357
2358  const MemberPointerType *MPT
2359    = E->getRHS()->getType()->getAs<MemberPointerType>();
2360
2361  llvm::Value *AddV =
2362    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
2363
2364  return MakeAddrLValue(AddV, MPT->getPointeeType());
2365}
2366