CGExpr.cpp revision e289d81369914678db386f6aa86faf8f178e245d 
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 "clang/Frontend/CodeGenOptions.h"
24#include "llvm/Intrinsics.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  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(llvm::Type *Ty,
48                                                    const 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 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 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,
140                                         AggValueSlot::IsDestructed_t(IsInit),
141                                         AggValueSlot::DoesNotNeedGCBarriers,
142                                         AggValueSlot::IsAliased_t(!IsInit)));
143  else {
144    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
145    LValue LV = MakeAddrLValue(Location, E->getType());
146    EmitStoreThroughLValue(RV, LV);
147  }
148}
149
150namespace {
151/// \brief An adjustment to be made to the temporary created when emitting a
152/// reference binding, which accesses a particular subobject of that temporary.
153  struct SubobjectAdjustment {
154    enum { DerivedToBaseAdjustment, FieldAdjustment } Kind;
155
156    union {
157      struct {
158        const CastExpr *BasePath;
159        const CXXRecordDecl *DerivedClass;
160      } DerivedToBase;
161
162      FieldDecl *Field;
163    };
164
165    SubobjectAdjustment(const CastExpr *BasePath,
166                        const CXXRecordDecl *DerivedClass)
167      : Kind(DerivedToBaseAdjustment) {
168      DerivedToBase.BasePath = BasePath;
169      DerivedToBase.DerivedClass = DerivedClass;
170    }
171
172    SubobjectAdjustment(FieldDecl *Field)
173      : Kind(FieldAdjustment) {
174      this->Field = Field;
175    }
176  };
177}
178
179static llvm::Value *
180CreateReferenceTemporary(CodeGenFunction &CGF, QualType Type,
181                         const NamedDecl *InitializedDecl) {
182  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
183    if (VD->hasGlobalStorage()) {
184      llvm::SmallString<256> Name;
185      llvm::raw_svector_ostream Out(Name);
186      CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Out);
187      Out.flush();
188
189      llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
190
191      // Create the reference temporary.
192      llvm::GlobalValue *RefTemp =
193        new llvm::GlobalVariable(CGF.CGM.getModule(),
194                                 RefTempTy, /*isConstant=*/false,
195                                 llvm::GlobalValue::InternalLinkage,
196                                 llvm::Constant::getNullValue(RefTempTy),
197                                 Name.str());
198      return RefTemp;
199    }
200  }
201
202  return CGF.CreateMemTemp(Type, "ref.tmp");
203}
204
205static llvm::Value *
206EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
207                            llvm::Value *&ReferenceTemporary,
208                            const CXXDestructorDecl *&ReferenceTemporaryDtor,
209                            QualType &ObjCARCReferenceLifetimeType,
210                            const NamedDecl *InitializedDecl) {
211  // Look through expressions for materialized temporaries (for now).
212  if (const MaterializeTemporaryExpr *M
213                                      = dyn_cast<MaterializeTemporaryExpr>(E)) {
214    // Objective-C++ ARC:
215    //   If we are binding a reference to a temporary that has ownership, we
216    //   need to perform retain/release operations on the temporary.
217    if (CGF.getContext().getLangOptions().ObjCAutoRefCount &&
218        E->getType()->isObjCLifetimeType() &&
219        (E->getType().getObjCLifetime() == Qualifiers::OCL_Strong ||
220         E->getType().getObjCLifetime() == Qualifiers::OCL_Weak ||
221         E->getType().getObjCLifetime() == Qualifiers::OCL_Autoreleasing))
222      ObjCARCReferenceLifetimeType = E->getType();
223
224    E = M->GetTemporaryExpr();
225  }
226
227  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
228    E = DAE->getExpr();
229
230  if (const ExprWithCleanups *TE = dyn_cast<ExprWithCleanups>(E)) {
231    CodeGenFunction::RunCleanupsScope Scope(CGF);
232
233    return EmitExprForReferenceBinding(CGF, TE->getSubExpr(),
234                                       ReferenceTemporary,
235                                       ReferenceTemporaryDtor,
236                                       ObjCARCReferenceLifetimeType,
237                                       InitializedDecl);
238  }
239
240  if (const ObjCPropertyRefExpr *PRE =
241      dyn_cast<ObjCPropertyRefExpr>(E->IgnoreParenImpCasts()))
242    if (PRE->getGetterResultType()->isReferenceType())
243      E = PRE;
244
245  RValue RV;
246  if (E->isGLValue()) {
247    // Emit the expression as an lvalue.
248    LValue LV = CGF.EmitLValue(E);
249    if (LV.isPropertyRef()) {
250      RV = CGF.EmitLoadOfPropertyRefLValue(LV);
251      return RV.getScalarVal();
252    }
253
254    if (LV.isSimple())
255      return LV.getAddress();
256
257    // We have to load the lvalue.
258    RV = CGF.EmitLoadOfLValue(LV);
259  } else {
260    if (!ObjCARCReferenceLifetimeType.isNull()) {
261      ReferenceTemporary = CreateReferenceTemporary(CGF,
262                                                  ObjCARCReferenceLifetimeType,
263                                                    InitializedDecl);
264
265
266      LValue RefTempDst = CGF.MakeAddrLValue(ReferenceTemporary,
267                                             ObjCARCReferenceLifetimeType);
268
269      CGF.EmitScalarInit(E, dyn_cast_or_null<ValueDecl>(InitializedDecl),
270                         RefTempDst, false);
271
272      bool ExtendsLifeOfTemporary = false;
273      if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
274        if (Var->extendsLifetimeOfTemporary())
275          ExtendsLifeOfTemporary = true;
276      } else if (InitializedDecl && isa<FieldDecl>(InitializedDecl)) {
277        ExtendsLifeOfTemporary = true;
278      }
279
280      if (!ExtendsLifeOfTemporary) {
281        // Since the lifetime of this temporary isn't going to be extended,
282        // we need to clean it up ourselves at the end of the full expression.
283        switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
284        case Qualifiers::OCL_None:
285        case Qualifiers::OCL_ExplicitNone:
286        case Qualifiers::OCL_Autoreleasing:
287          break;
288
289        case Qualifiers::OCL_Strong: {
290          assert(!ObjCARCReferenceLifetimeType->isArrayType());
291          CleanupKind cleanupKind = CGF.getARCCleanupKind();
292          CGF.pushDestroy(cleanupKind,
293                          ReferenceTemporary,
294                          ObjCARCReferenceLifetimeType,
295                          CodeGenFunction::destroyARCStrongImprecise,
296                          cleanupKind & EHCleanup);
297          break;
298        }
299
300        case Qualifiers::OCL_Weak:
301          assert(!ObjCARCReferenceLifetimeType->isArrayType());
302          CGF.pushDestroy(NormalAndEHCleanup,
303                          ReferenceTemporary,
304                          ObjCARCReferenceLifetimeType,
305                          CodeGenFunction::destroyARCWeak,
306                          /*useEHCleanupForArray*/ true);
307          break;
308        }
309
310        ObjCARCReferenceLifetimeType = QualType();
311      }
312
313      return ReferenceTemporary;
314    }
315
316    SmallVector<SubobjectAdjustment, 2> Adjustments;
317    while (true) {
318      E = E->IgnoreParens();
319
320      if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
321        if ((CE->getCastKind() == CK_DerivedToBase ||
322             CE->getCastKind() == CK_UncheckedDerivedToBase) &&
323            E->getType()->isRecordType()) {
324          E = CE->getSubExpr();
325          CXXRecordDecl *Derived
326            = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
327          Adjustments.push_back(SubobjectAdjustment(CE, Derived));
328          continue;
329        }
330
331        if (CE->getCastKind() == CK_NoOp) {
332          E = CE->getSubExpr();
333          continue;
334        }
335      } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
336        if (!ME->isArrow() && ME->getBase()->isRValue()) {
337          assert(ME->getBase()->getType()->isRecordType());
338          if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
339            E = ME->getBase();
340            Adjustments.push_back(SubobjectAdjustment(Field));
341            continue;
342          }
343        }
344      }
345
346      if (const OpaqueValueExpr *opaque = dyn_cast<OpaqueValueExpr>(E))
347        if (opaque->getType()->isRecordType())
348          return CGF.EmitOpaqueValueLValue(opaque).getAddress();
349
350      // Nothing changed.
351      break;
352    }
353
354    // Create a reference temporary if necessary.
355    AggValueSlot AggSlot = AggValueSlot::ignored();
356    if (CGF.hasAggregateLLVMType(E->getType()) &&
357        !E->getType()->isAnyComplexType()) {
358      ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
359                                                    InitializedDecl);
360      AggValueSlot::IsDestructed_t isDestructed
361        = AggValueSlot::IsDestructed_t(InitializedDecl != 0);
362      AggSlot = AggValueSlot::forAddr(ReferenceTemporary, Qualifiers(),
363                                      isDestructed,
364                                      AggValueSlot::DoesNotNeedGCBarriers,
365                                      AggValueSlot::IsNotAliased);
366    }
367
368    if (InitializedDecl) {
369      // Get the destructor for the reference temporary.
370      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
371        CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
372        if (!ClassDecl->hasTrivialDestructor())
373          ReferenceTemporaryDtor = ClassDecl->getDestructor();
374      }
375    }
376
377    RV = CGF.EmitAnyExpr(E, AggSlot);
378
379    // Check if need to perform derived-to-base casts and/or field accesses, to
380    // get from the temporary object we created (and, potentially, for which we
381    // extended the lifetime) to the subobject we're binding the reference to.
382    if (!Adjustments.empty()) {
383      llvm::Value *Object = RV.getAggregateAddr();
384      for (unsigned I = Adjustments.size(); I != 0; --I) {
385        SubobjectAdjustment &Adjustment = Adjustments[I-1];
386        switch (Adjustment.Kind) {
387        case SubobjectAdjustment::DerivedToBaseAdjustment:
388          Object =
389              CGF.GetAddressOfBaseClass(Object,
390                                        Adjustment.DerivedToBase.DerivedClass,
391                              Adjustment.DerivedToBase.BasePath->path_begin(),
392                              Adjustment.DerivedToBase.BasePath->path_end(),
393                                        /*NullCheckValue=*/false);
394          break;
395
396        case SubobjectAdjustment::FieldAdjustment: {
397          LValue LV =
398            CGF.EmitLValueForField(Object, Adjustment.Field, 0);
399          if (LV.isSimple()) {
400            Object = LV.getAddress();
401            break;
402          }
403
404          // For non-simple lvalues, we actually have to create a copy of
405          // the object we're binding to.
406          QualType T = Adjustment.Field->getType().getNonReferenceType()
407                                                  .getUnqualifiedType();
408          Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
409          LValue TempLV = CGF.MakeAddrLValue(Object,
410                                             Adjustment.Field->getType());
411          CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV), TempLV);
412          break;
413        }
414
415        }
416      }
417
418      return Object;
419    }
420  }
421
422  if (RV.isAggregate())
423    return RV.getAggregateAddr();
424
425  // Create a temporary variable that we can bind the reference to.
426  ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
427                                                InitializedDecl);
428
429
430  unsigned Alignment =
431    CGF.getContext().getTypeAlignInChars(E->getType()).getQuantity();
432  if (RV.isScalar())
433    CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
434                          /*Volatile=*/false, Alignment, E->getType());
435  else
436    CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
437                           /*Volatile=*/false);
438  return ReferenceTemporary;
439}
440
441RValue
442CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
443                                            const NamedDecl *InitializedDecl) {
444  llvm::Value *ReferenceTemporary = 0;
445  const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
446  QualType ObjCARCReferenceLifetimeType;
447  llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
448                                                   ReferenceTemporaryDtor,
449                                                   ObjCARCReferenceLifetimeType,
450                                                   InitializedDecl);
451  if (!ReferenceTemporaryDtor && ObjCARCReferenceLifetimeType.isNull())
452    return RValue::get(Value);
453
454  // Make sure to call the destructor for the reference temporary.
455  const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl);
456  if (VD && VD->hasGlobalStorage()) {
457    if (ReferenceTemporaryDtor) {
458      llvm::Constant *DtorFn =
459        CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
460      EmitCXXGlobalDtorRegistration(DtorFn,
461                                    cast<llvm::Constant>(ReferenceTemporary));
462    } else {
463      assert(!ObjCARCReferenceLifetimeType.isNull());
464      // Note: We intentionally do not register a global "destructor" to
465      // release the object.
466    }
467
468    return RValue::get(Value);
469  }
470
471  if (ReferenceTemporaryDtor)
472    PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
473  else {
474    switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
475    case Qualifiers::OCL_None:
476      assert(0 && "Not a reference temporary that needs to be deallocated");
477    case Qualifiers::OCL_ExplicitNone:
478    case Qualifiers::OCL_Autoreleasing:
479      // Nothing to do.
480      break;
481
482    case Qualifiers::OCL_Strong: {
483      bool precise = VD && VD->hasAttr<ObjCPreciseLifetimeAttr>();
484      CleanupKind cleanupKind = getARCCleanupKind();
485      // This local is a GCC and MSVC compiler workaround.
486      Destroyer *destroyer = precise ? &destroyARCStrongPrecise :
487                                       &destroyARCStrongImprecise;
488      pushDestroy(cleanupKind, ReferenceTemporary, ObjCARCReferenceLifetimeType,
489                  *destroyer, cleanupKind & EHCleanup);
490      break;
491    }
492
493    case Qualifiers::OCL_Weak: {
494      // This local is a GCC and MSVC compiler workaround.
495      Destroyer *destroyer = &destroyARCWeak;
496      // __weak objects always get EH cleanups; otherwise, exceptions
497      // could cause really nasty crashes instead of mere leaks.
498      pushDestroy(NormalAndEHCleanup, ReferenceTemporary,
499                  ObjCARCReferenceLifetimeType, *destroyer, true);
500      break;
501    }
502    }
503  }
504
505  return RValue::get(Value);
506}
507
508
509/// getAccessedFieldNo - Given an encoded value and a result number, return the
510/// input field number being accessed.
511unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
512                                             const llvm::Constant *Elts) {
513  if (isa<llvm::ConstantAggregateZero>(Elts))
514    return 0;
515
516  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
517}
518
519void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
520  if (!CatchUndefined)
521    return;
522
523  // This needs to be to the standard address space.
524  Address = Builder.CreateBitCast(Address, Int8PtrTy);
525
526  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, IntPtrTy);
527
528  // In time, people may want to control this and use a 1 here.
529  llvm::Value *Arg = Builder.getFalse();
530  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
531  llvm::BasicBlock *Cont = createBasicBlock();
532  llvm::BasicBlock *Check = createBasicBlock();
533  llvm::Value *NegativeOne = llvm::ConstantInt::get(IntPtrTy, -1ULL);
534  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
535
536  EmitBlock(Check);
537  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
538                                        llvm::ConstantInt::get(IntPtrTy, Size)),
539                       Cont, getTrapBB());
540  EmitBlock(Cont);
541}
542
543
544CodeGenFunction::ComplexPairTy CodeGenFunction::
545EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
546                         bool isInc, bool isPre) {
547  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
548                                            LV.isVolatileQualified());
549
550  llvm::Value *NextVal;
551  if (isa<llvm::IntegerType>(InVal.first->getType())) {
552    uint64_t AmountVal = isInc ? 1 : -1;
553    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
554
555    // Add the inc/dec to the real part.
556    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
557  } else {
558    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
559    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
560    if (!isInc)
561      FVal.changeSign();
562    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
563
564    // Add the inc/dec to the real part.
565    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
566  }
567
568  ComplexPairTy IncVal(NextVal, InVal.second);
569
570  // Store the updated result through the lvalue.
571  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
572
573  // If this is a postinc, return the value read from memory, otherwise use the
574  // updated value.
575  return isPre ? IncVal : InVal;
576}
577
578
579//===----------------------------------------------------------------------===//
580//                         LValue Expression Emission
581//===----------------------------------------------------------------------===//
582
583RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
584  if (Ty->isVoidType())
585    return RValue::get(0);
586
587  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
588    llvm::Type *EltTy = ConvertType(CTy->getElementType());
589    llvm::Value *U = llvm::UndefValue::get(EltTy);
590    return RValue::getComplex(std::make_pair(U, U));
591  }
592
593  // If this is a use of an undefined aggregate type, the aggregate must have an
594  // identifiable address.  Just because the contents of the value are undefined
595  // doesn't mean that the address can't be taken and compared.
596  if (hasAggregateLLVMType(Ty)) {
597    llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
598    return RValue::getAggregate(DestPtr);
599  }
600
601  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
602}
603
604RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
605                                              const char *Name) {
606  ErrorUnsupported(E, Name);
607  return GetUndefRValue(E->getType());
608}
609
610LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
611                                              const char *Name) {
612  ErrorUnsupported(E, Name);
613  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
614  return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
615}
616
617LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
618  LValue LV = EmitLValue(E);
619  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
620    EmitCheck(LV.getAddress(),
621              getContext().getTypeSizeInChars(E->getType()).getQuantity());
622  return LV;
623}
624
625/// EmitLValue - Emit code to compute a designator that specifies the location
626/// of the expression.
627///
628/// This can return one of two things: a simple address or a bitfield reference.
629/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
630/// an LLVM pointer type.
631///
632/// If this returns a bitfield reference, nothing about the pointee type of the
633/// LLVM value is known: For example, it may not be a pointer to an integer.
634///
635/// If this returns a normal address, and if the lvalue's C type is fixed size,
636/// this method guarantees that the returned pointer type will point to an LLVM
637/// type of the same size of the lvalue's type.  If the lvalue has a variable
638/// length type, this is not possible.
639///
640LValue CodeGenFunction::EmitLValue(const Expr *E) {
641  switch (E->getStmtClass()) {
642  default: return EmitUnsupportedLValue(E, "l-value expression");
643
644  case Expr::ObjCSelectorExprClass:
645  return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
646  case Expr::ObjCIsaExprClass:
647    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
648  case Expr::BinaryOperatorClass:
649    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
650  case Expr::CompoundAssignOperatorClass:
651    if (!E->getType()->isAnyComplexType())
652      return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
653    return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
654  case Expr::CallExprClass:
655  case Expr::CXXMemberCallExprClass:
656  case Expr::CXXOperatorCallExprClass:
657    return EmitCallExprLValue(cast<CallExpr>(E));
658  case Expr::VAArgExprClass:
659    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
660  case Expr::DeclRefExprClass:
661    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
662  case Expr::ParenExprClass:
663    return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
664  case Expr::GenericSelectionExprClass:
665    return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
666  case Expr::PredefinedExprClass:
667    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
668  case Expr::StringLiteralClass:
669    return EmitStringLiteralLValue(cast<StringLiteral>(E));
670  case Expr::ObjCEncodeExprClass:
671    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
672
673  case Expr::BlockDeclRefExprClass:
674    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
675
676  case Expr::CXXTemporaryObjectExprClass:
677  case Expr::CXXConstructExprClass:
678    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
679  case Expr::CXXBindTemporaryExprClass:
680    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
681  case Expr::ExprWithCleanupsClass:
682    return EmitExprWithCleanupsLValue(cast<ExprWithCleanups>(E));
683  case Expr::CXXScalarValueInitExprClass:
684    return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
685  case Expr::CXXDefaultArgExprClass:
686    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
687  case Expr::CXXTypeidExprClass:
688    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
689
690  case Expr::ObjCMessageExprClass:
691    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
692  case Expr::ObjCIvarRefExprClass:
693    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
694  case Expr::ObjCPropertyRefExprClass:
695    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
696  case Expr::StmtExprClass:
697    return EmitStmtExprLValue(cast<StmtExpr>(E));
698  case Expr::UnaryOperatorClass:
699    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
700  case Expr::ArraySubscriptExprClass:
701    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
702  case Expr::ExtVectorElementExprClass:
703    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
704  case Expr::MemberExprClass:
705    return EmitMemberExpr(cast<MemberExpr>(E));
706  case Expr::CompoundLiteralExprClass:
707    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
708  case Expr::ConditionalOperatorClass:
709    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
710  case Expr::BinaryConditionalOperatorClass:
711    return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
712  case Expr::ChooseExprClass:
713    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
714  case Expr::OpaqueValueExprClass:
715    return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
716  case Expr::SubstNonTypeTemplateParmExprClass:
717    return EmitLValue(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
718  case Expr::ImplicitCastExprClass:
719  case Expr::CStyleCastExprClass:
720  case Expr::CXXFunctionalCastExprClass:
721  case Expr::CXXStaticCastExprClass:
722  case Expr::CXXDynamicCastExprClass:
723  case Expr::CXXReinterpretCastExprClass:
724  case Expr::CXXConstCastExprClass:
725  case Expr::ObjCBridgedCastExprClass:
726    return EmitCastLValue(cast<CastExpr>(E));
727
728  case Expr::MaterializeTemporaryExprClass:
729    return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
730  }
731}
732
733llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue) {
734  return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
735                          lvalue.getAlignment(), lvalue.getType(),
736                          lvalue.getTBAAInfo());
737}
738
739llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
740                                              unsigned Alignment, QualType Ty,
741                                              llvm::MDNode *TBAAInfo) {
742  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
743  if (Volatile)
744    Load->setVolatile(true);
745  if (Alignment)
746    Load->setAlignment(Alignment);
747  if (TBAAInfo)
748    CGM.DecorateInstruction(Load, TBAAInfo);
749
750  return EmitFromMemory(Load, Ty);
751}
752
753static bool isBooleanUnderlyingType(QualType Ty) {
754  if (const EnumType *ET = dyn_cast<EnumType>(Ty))
755    return ET->getDecl()->getIntegerType()->isBooleanType();
756  return false;
757}
758
759llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
760  // Bool has a different representation in memory than in registers.
761  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
762    // This should really always be an i1, but sometimes it's already
763    // an i8, and it's awkward to track those cases down.
764    if (Value->getType()->isIntegerTy(1))
765      return Builder.CreateZExt(Value, Builder.getInt8Ty(), "frombool");
766    assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
767  }
768
769  return Value;
770}
771
772llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
773  // Bool has a different representation in memory than in registers.
774  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
775    assert(Value->getType()->isIntegerTy(8) && "memory rep of bool not i8");
776    return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
777  }
778
779  return Value;
780}
781
782void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
783                                        bool Volatile, unsigned Alignment,
784                                        QualType Ty,
785                                        llvm::MDNode *TBAAInfo) {
786  Value = EmitToMemory(Value, Ty);
787
788  llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
789  if (Alignment)
790    Store->setAlignment(Alignment);
791  if (TBAAInfo)
792    CGM.DecorateInstruction(Store, TBAAInfo);
793}
794
795void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue) {
796  EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
797                    lvalue.getAlignment(), lvalue.getType(),
798                    lvalue.getTBAAInfo());
799}
800
801/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
802/// method emits the address of the lvalue, then loads the result as an rvalue,
803/// returning the rvalue.
804RValue CodeGenFunction::EmitLoadOfLValue(LValue LV) {
805  if (LV.isObjCWeak()) {
806    // load of a __weak object.
807    llvm::Value *AddrWeakObj = LV.getAddress();
808    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
809                                                             AddrWeakObj));
810  }
811  if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak)
812    return RValue::get(EmitARCLoadWeak(LV.getAddress()));
813
814  if (LV.isSimple()) {
815    assert(!LV.getType()->isFunctionType());
816
817    // Everything needs a load.
818    return RValue::get(EmitLoadOfScalar(LV));
819  }
820
821  if (LV.isVectorElt()) {
822    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
823                                          LV.isVolatileQualified(), "tmp");
824    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
825                                                    "vecext"));
826  }
827
828  // If this is a reference to a subset of the elements of a vector, either
829  // shuffle the input or extract/insert them as appropriate.
830  if (LV.isExtVectorElt())
831    return EmitLoadOfExtVectorElementLValue(LV);
832
833  if (LV.isBitField())
834    return EmitLoadOfBitfieldLValue(LV);
835
836  assert(LV.isPropertyRef() && "Unknown LValue type!");
837  return EmitLoadOfPropertyRefLValue(LV);
838}
839
840RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV) {
841  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
842
843  // Get the output type.
844  llvm::Type *ResLTy = ConvertType(LV.getType());
845  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
846
847  // Compute the result as an OR of all of the individual component accesses.
848  llvm::Value *Res = 0;
849  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
850    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
851
852    // Get the field pointer.
853    llvm::Value *Ptr = LV.getBitFieldBaseAddr();
854
855    // Only offset by the field index if used, so that incoming values are not
856    // required to be structures.
857    if (AI.FieldIndex)
858      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
859
860    // Offset by the byte offset, if used.
861    if (!AI.FieldByteOffset.isZero()) {
862      Ptr = EmitCastToVoidPtr(Ptr);
863      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
864                                       "bf.field.offs");
865    }
866
867    // Cast to the access type.
868    llvm::Type *PTy = llvm::Type::getIntNPtrTy(getLLVMContext(),
869                                                     AI.AccessWidth,
870                       CGM.getContext().getTargetAddressSpace(LV.getType()));
871    Ptr = Builder.CreateBitCast(Ptr, PTy);
872
873    // Perform the load.
874    llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
875    if (!AI.AccessAlignment.isZero())
876      Load->setAlignment(AI.AccessAlignment.getQuantity());
877
878    // Shift out unused low bits and mask out unused high bits.
879    llvm::Value *Val = Load;
880    if (AI.FieldBitStart)
881      Val = Builder.CreateLShr(Load, AI.FieldBitStart);
882    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
883                                                            AI.TargetBitWidth),
884                            "bf.clear");
885
886    // Extend or truncate to the target size.
887    if (AI.AccessWidth < ResSizeInBits)
888      Val = Builder.CreateZExt(Val, ResLTy);
889    else if (AI.AccessWidth > ResSizeInBits)
890      Val = Builder.CreateTrunc(Val, ResLTy);
891
892    // Shift into place, and OR into the result.
893    if (AI.TargetBitOffset)
894      Val = Builder.CreateShl(Val, AI.TargetBitOffset);
895    Res = Res ? Builder.CreateOr(Res, Val) : Val;
896  }
897
898  // If the bit-field is signed, perform the sign-extension.
899  //
900  // FIXME: This can easily be folded into the load of the high bits, which
901  // could also eliminate the mask of high bits in some situations.
902  if (Info.isSigned()) {
903    unsigned ExtraBits = ResSizeInBits - Info.getSize();
904    if (ExtraBits)
905      Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
906                               ExtraBits, "bf.val.sext");
907  }
908
909  return RValue::get(Res);
910}
911
912// If this is a reference to a subset of the elements of a vector, create an
913// appropriate shufflevector.
914RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) {
915  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
916                                        LV.isVolatileQualified(), "tmp");
917
918  const llvm::Constant *Elts = LV.getExtVectorElts();
919
920  // If the result of the expression is a non-vector type, we must be extracting
921  // a single element.  Just codegen as an extractelement.
922  const VectorType *ExprVT = LV.getType()->getAs<VectorType>();
923  if (!ExprVT) {
924    unsigned InIdx = getAccessedFieldNo(0, Elts);
925    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
926    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
927  }
928
929  // Always use shuffle vector to try to retain the original program structure
930  unsigned NumResultElts = ExprVT->getNumElements();
931
932  SmallVector<llvm::Constant*, 4> Mask;
933  for (unsigned i = 0; i != NumResultElts; ++i) {
934    unsigned InIdx = getAccessedFieldNo(i, Elts);
935    Mask.push_back(llvm::ConstantInt::get(Int32Ty, InIdx));
936  }
937
938  llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
939  Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()),
940                                    MaskV, "tmp");
941  return RValue::get(Vec);
942}
943
944
945
946/// EmitStoreThroughLValue - Store the specified rvalue into the specified
947/// lvalue, where both are guaranteed to the have the same type, and that type
948/// is 'Ty'.
949void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst) {
950  if (!Dst.isSimple()) {
951    if (Dst.isVectorElt()) {
952      // Read/modify/write the vector, inserting the new element.
953      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
954                                            Dst.isVolatileQualified(), "tmp");
955      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
956                                        Dst.getVectorIdx(), "vecins");
957      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
958      return;
959    }
960
961    // If this is an update of extended vector elements, insert them as
962    // appropriate.
963    if (Dst.isExtVectorElt())
964      return EmitStoreThroughExtVectorComponentLValue(Src, Dst);
965
966    if (Dst.isBitField())
967      return EmitStoreThroughBitfieldLValue(Src, Dst);
968
969    assert(Dst.isPropertyRef() && "Unknown LValue type");
970    return EmitStoreThroughPropertyRefLValue(Src, Dst);
971  }
972
973  // There's special magic for assigning into an ARC-qualified l-value.
974  if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) {
975    switch (Lifetime) {
976    case Qualifiers::OCL_None:
977      llvm_unreachable("present but none");
978
979    case Qualifiers::OCL_ExplicitNone:
980      // nothing special
981      break;
982
983    case Qualifiers::OCL_Strong:
984      EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
985      return;
986
987    case Qualifiers::OCL_Weak:
988      EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
989      return;
990
991    case Qualifiers::OCL_Autoreleasing:
992      Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(),
993                                                     Src.getScalarVal()));
994      // fall into the normal path
995      break;
996    }
997  }
998
999  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
1000    // load of a __weak object.
1001    llvm::Value *LvalueDst = Dst.getAddress();
1002    llvm::Value *src = Src.getScalarVal();
1003     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
1004    return;
1005  }
1006
1007  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
1008    // load of a __strong object.
1009    llvm::Value *LvalueDst = Dst.getAddress();
1010    llvm::Value *src = Src.getScalarVal();
1011    if (Dst.isObjCIvar()) {
1012      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
1013      llvm::Type *ResultType = ConvertType(getContext().LongTy);
1014      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
1015      llvm::Value *dst = RHS;
1016      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
1017      llvm::Value *LHS =
1018        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
1019      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
1020      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
1021                                              BytesBetween);
1022    } else if (Dst.isGlobalObjCRef()) {
1023      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
1024                                                Dst.isThreadLocalRef());
1025    }
1026    else
1027      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
1028    return;
1029  }
1030
1031  assert(Src.isScalar() && "Can't emit an agg store with this method");
1032  EmitStoreOfScalar(Src.getScalarVal(), Dst);
1033}
1034
1035void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
1036                                                     llvm::Value **Result) {
1037  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
1038
1039  // Get the output type.
1040  llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
1041  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
1042
1043  // Get the source value, truncated to the width of the bit-field.
1044  llvm::Value *SrcVal = Src.getScalarVal();
1045
1046  if (Dst.getType()->isBooleanType())
1047    SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
1048
1049  SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
1050                                                                Info.getSize()),
1051                             "bf.value");
1052
1053  // Return the new value of the bit-field, if requested.
1054  if (Result) {
1055    // Cast back to the proper type for result.
1056    llvm::Type *SrcTy = Src.getScalarVal()->getType();
1057    llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
1058                                                   "bf.reload.val");
1059
1060    // Sign extend if necessary.
1061    if (Info.isSigned()) {
1062      unsigned ExtraBits = ResSizeInBits - Info.getSize();
1063      if (ExtraBits)
1064        ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
1065                                       ExtraBits, "bf.reload.sext");
1066    }
1067
1068    *Result = ReloadVal;
1069  }
1070
1071  // Iterate over the components, writing each piece to memory.
1072  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
1073    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
1074
1075    // Get the field pointer.
1076    llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
1077    unsigned addressSpace =
1078      cast<llvm::PointerType>(Ptr->getType())->getAddressSpace();
1079
1080    // Only offset by the field index if used, so that incoming values are not
1081    // required to be structures.
1082    if (AI.FieldIndex)
1083      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
1084
1085    // Offset by the byte offset, if used.
1086    if (!AI.FieldByteOffset.isZero()) {
1087      Ptr = EmitCastToVoidPtr(Ptr);
1088      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
1089                                       "bf.field.offs");
1090    }
1091
1092    // Cast to the access type.
1093    llvm::Type *AccessLTy =
1094      llvm::Type::getIntNTy(getLLVMContext(), AI.AccessWidth);
1095
1096    llvm::Type *PTy = AccessLTy->getPointerTo(addressSpace);
1097    Ptr = Builder.CreateBitCast(Ptr, PTy);
1098
1099    // Extract the piece of the bit-field value to write in this access, limited
1100    // to the values that are part of this access.
1101    llvm::Value *Val = SrcVal;
1102    if (AI.TargetBitOffset)
1103      Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
1104    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
1105                                                            AI.TargetBitWidth));
1106
1107    // Extend or truncate to the access size.
1108    if (ResSizeInBits < AI.AccessWidth)
1109      Val = Builder.CreateZExt(Val, AccessLTy);
1110    else if (ResSizeInBits > AI.AccessWidth)
1111      Val = Builder.CreateTrunc(Val, AccessLTy);
1112
1113    // Shift into the position in memory.
1114    if (AI.FieldBitStart)
1115      Val = Builder.CreateShl(Val, AI.FieldBitStart);
1116
1117    // If necessary, load and OR in bits that are outside of the bit-field.
1118    if (AI.TargetBitWidth != AI.AccessWidth) {
1119      llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
1120      if (!AI.AccessAlignment.isZero())
1121        Load->setAlignment(AI.AccessAlignment.getQuantity());
1122
1123      // Compute the mask for zeroing the bits that are part of the bit-field.
1124      llvm::APInt InvMask =
1125        ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
1126                                 AI.FieldBitStart + AI.TargetBitWidth);
1127
1128      // Apply the mask and OR in to the value to write.
1129      Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
1130    }
1131
1132    // Write the value.
1133    llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
1134                                                 Dst.isVolatileQualified());
1135    if (!AI.AccessAlignment.isZero())
1136      Store->setAlignment(AI.AccessAlignment.getQuantity());
1137  }
1138}
1139
1140void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
1141                                                               LValue Dst) {
1142  // This access turns into a read/modify/write of the vector.  Load the input
1143  // value now.
1144  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
1145                                        Dst.isVolatileQualified(), "tmp");
1146  const llvm::Constant *Elts = Dst.getExtVectorElts();
1147
1148  llvm::Value *SrcVal = Src.getScalarVal();
1149
1150  if (const VectorType *VTy = Dst.getType()->getAs<VectorType>()) {
1151    unsigned NumSrcElts = VTy->getNumElements();
1152    unsigned NumDstElts =
1153       cast<llvm::VectorType>(Vec->getType())->getNumElements();
1154    if (NumDstElts == NumSrcElts) {
1155      // Use shuffle vector is the src and destination are the same number of
1156      // elements and restore the vector mask since it is on the side it will be
1157      // stored.
1158      SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
1159      for (unsigned i = 0; i != NumSrcElts; ++i) {
1160        unsigned InIdx = getAccessedFieldNo(i, Elts);
1161        Mask[InIdx] = llvm::ConstantInt::get(Int32Ty, i);
1162      }
1163
1164      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1165      Vec = Builder.CreateShuffleVector(SrcVal,
1166                                        llvm::UndefValue::get(Vec->getType()),
1167                                        MaskV, "tmp");
1168    } else if (NumDstElts > NumSrcElts) {
1169      // Extended the source vector to the same length and then shuffle it
1170      // into the destination.
1171      // FIXME: since we're shuffling with undef, can we just use the indices
1172      //        into that?  This could be simpler.
1173      SmallVector<llvm::Constant*, 4> ExtMask;
1174      unsigned i;
1175      for (i = 0; i != NumSrcElts; ++i)
1176        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1177      for (; i != NumDstElts; ++i)
1178        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
1179      llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
1180      llvm::Value *ExtSrcVal =
1181        Builder.CreateShuffleVector(SrcVal,
1182                                    llvm::UndefValue::get(SrcVal->getType()),
1183                                    ExtMaskV, "tmp");
1184      // build identity
1185      SmallVector<llvm::Constant*, 4> Mask;
1186      for (unsigned i = 0; i != NumDstElts; ++i)
1187        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1188
1189      // modify when what gets shuffled in
1190      for (unsigned i = 0; i != NumSrcElts; ++i) {
1191        unsigned Idx = getAccessedFieldNo(i, Elts);
1192        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
1193      }
1194      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1195      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
1196    } else {
1197      // We should never shorten the vector
1198      assert(0 && "unexpected shorten vector length");
1199    }
1200  } else {
1201    // If the Src is a scalar (not a vector) it must be updating one element.
1202    unsigned InIdx = getAccessedFieldNo(0, Elts);
1203    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1204    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
1205  }
1206
1207  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1208}
1209
1210// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1211// generating write-barries API. It is currently a global, ivar,
1212// or neither.
1213static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1214                                 LValue &LV) {
1215  if (Ctx.getLangOptions().getGC() == LangOptions::NonGC)
1216    return;
1217
1218  if (isa<ObjCIvarRefExpr>(E)) {
1219    LV.setObjCIvar(true);
1220    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1221    LV.setBaseIvarExp(Exp->getBase());
1222    LV.setObjCArray(E->getType()->isArrayType());
1223    return;
1224  }
1225
1226  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1227    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1228      if (VD->hasGlobalStorage()) {
1229        LV.setGlobalObjCRef(true);
1230        LV.setThreadLocalRef(VD->isThreadSpecified());
1231      }
1232    }
1233    LV.setObjCArray(E->getType()->isArrayType());
1234    return;
1235  }
1236
1237  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1238    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1239    return;
1240  }
1241
1242  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1243    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1244    if (LV.isObjCIvar()) {
1245      // If cast is to a structure pointer, follow gcc's behavior and make it
1246      // a non-ivar write-barrier.
1247      QualType ExpTy = E->getType();
1248      if (ExpTy->isPointerType())
1249        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1250      if (ExpTy->isRecordType())
1251        LV.setObjCIvar(false);
1252    }
1253    return;
1254  }
1255
1256  if (const GenericSelectionExpr *Exp = dyn_cast<GenericSelectionExpr>(E)) {
1257    setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
1258    return;
1259  }
1260
1261  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1262    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1263    return;
1264  }
1265
1266  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1267    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1268    return;
1269  }
1270
1271  if (const ObjCBridgedCastExpr *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
1272    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1273    return;
1274  }
1275
1276  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1277    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1278    if (LV.isObjCIvar() && !LV.isObjCArray())
1279      // Using array syntax to assigning to what an ivar points to is not
1280      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1281      LV.setObjCIvar(false);
1282    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1283      // Using array syntax to assigning to what global points to is not
1284      // same as assigning to the global itself. {id *G;} G[i] = 0;
1285      LV.setGlobalObjCRef(false);
1286    return;
1287  }
1288
1289  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1290    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1291    // We don't know if member is an 'ivar', but this flag is looked at
1292    // only in the context of LV.isObjCIvar().
1293    LV.setObjCArray(E->getType()->isArrayType());
1294    return;
1295  }
1296}
1297
1298static llvm::Value *
1299EmitBitCastOfLValueToProperType(CodeGenFunction &CGF,
1300                                llvm::Value *V, llvm::Type *IRType,
1301                                StringRef Name = StringRef()) {
1302  unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
1303  return CGF.Builder.CreateBitCast(V, IRType->getPointerTo(AS), Name);
1304}
1305
1306static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1307                                      const Expr *E, const VarDecl *VD) {
1308  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1309         "Var decl must have external storage or be a file var decl!");
1310
1311  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1312  if (VD->getType()->isReferenceType())
1313    V = CGF.Builder.CreateLoad(V, "tmp");
1314
1315  V = EmitBitCastOfLValueToProperType(CGF, V,
1316                                CGF.getTypes().ConvertTypeForMem(E->getType()));
1317
1318  unsigned Alignment = CGF.getContext().getDeclAlign(VD).getQuantity();
1319  LValue LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1320  setObjCGCLValueClass(CGF.getContext(), E, LV);
1321  return LV;
1322}
1323
1324static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1325                                     const Expr *E, const FunctionDecl *FD) {
1326  llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1327  if (!FD->hasPrototype()) {
1328    if (const FunctionProtoType *Proto =
1329            FD->getType()->getAs<FunctionProtoType>()) {
1330      // Ugly case: for a K&R-style definition, the type of the definition
1331      // isn't the same as the type of a use.  Correct for this with a
1332      // bitcast.
1333      QualType NoProtoType =
1334          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1335      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1336      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1337    }
1338  }
1339  unsigned Alignment = CGF.getContext().getDeclAlign(FD).getQuantity();
1340  return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1341}
1342
1343LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1344  const NamedDecl *ND = E->getDecl();
1345  unsigned Alignment = getContext().getDeclAlign(ND).getQuantity();
1346
1347  if (ND->hasAttr<WeakRefAttr>()) {
1348    const ValueDecl *VD = cast<ValueDecl>(ND);
1349    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1350    return MakeAddrLValue(Aliasee, E->getType(), Alignment);
1351  }
1352
1353  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1354
1355    // Check if this is a global variable.
1356    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1357      return EmitGlobalVarDeclLValue(*this, E, VD);
1358
1359    bool NonGCable = VD->hasLocalStorage() &&
1360                     !VD->getType()->isReferenceType() &&
1361                     !VD->hasAttr<BlocksAttr>();
1362
1363    llvm::Value *V = LocalDeclMap[VD];
1364    if (!V && VD->isStaticLocal())
1365      V = CGM.getStaticLocalDeclAddress(VD);
1366    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1367
1368    if (VD->hasAttr<BlocksAttr>())
1369      V = BuildBlockByrefAddress(V, VD);
1370
1371    if (VD->getType()->isReferenceType())
1372      V = Builder.CreateLoad(V, "tmp");
1373
1374    V = EmitBitCastOfLValueToProperType(*this, V,
1375                                    getTypes().ConvertTypeForMem(E->getType()));
1376
1377    LValue LV = MakeAddrLValue(V, E->getType(), Alignment);
1378    if (NonGCable) {
1379      LV.getQuals().removeObjCGCAttr();
1380      LV.setNonGC(true);
1381    }
1382    setObjCGCLValueClass(getContext(), E, LV);
1383    return LV;
1384  }
1385
1386  if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
1387    return EmitFunctionDeclLValue(*this, E, fn);
1388
1389  assert(false && "Unhandled DeclRefExpr");
1390
1391  // an invalid LValue, but the assert will
1392  // ensure that this point is never reached.
1393  return LValue();
1394}
1395
1396LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1397  unsigned Alignment =
1398    getContext().getDeclAlign(E->getDecl()).getQuantity();
1399  return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
1400}
1401
1402LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1403  // __extension__ doesn't affect lvalue-ness.
1404  if (E->getOpcode() == UO_Extension)
1405    return EmitLValue(E->getSubExpr());
1406
1407  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1408  switch (E->getOpcode()) {
1409  default: assert(0 && "Unknown unary operator lvalue!");
1410  case UO_Deref: {
1411    QualType T = E->getSubExpr()->getType()->getPointeeType();
1412    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1413
1414    LValue LV = MakeAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1415    LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1416
1417    // We should not generate __weak write barrier on indirect reference
1418    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1419    // But, we continue to generate __strong write barrier on indirect write
1420    // into a pointer to object.
1421    if (getContext().getLangOptions().ObjC1 &&
1422        getContext().getLangOptions().getGC() != LangOptions::NonGC &&
1423        LV.isObjCWeak())
1424      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1425    return LV;
1426  }
1427  case UO_Real:
1428  case UO_Imag: {
1429    LValue LV = EmitLValue(E->getSubExpr());
1430    assert(LV.isSimple() && "real/imag on non-ordinary l-value");
1431    llvm::Value *Addr = LV.getAddress();
1432
1433    // real and imag are valid on scalars.  This is a faster way of
1434    // testing that.
1435    if (!cast<llvm::PointerType>(Addr->getType())
1436           ->getElementType()->isStructTy()) {
1437      assert(E->getSubExpr()->getType()->isArithmeticType());
1438      return LV;
1439    }
1440
1441    assert(E->getSubExpr()->getType()->isAnyComplexType());
1442
1443    unsigned Idx = E->getOpcode() == UO_Imag;
1444    return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1445                                                  Idx, "idx"),
1446                          ExprTy);
1447  }
1448  case UO_PreInc:
1449  case UO_PreDec: {
1450    LValue LV = EmitLValue(E->getSubExpr());
1451    bool isInc = E->getOpcode() == UO_PreInc;
1452
1453    if (E->getType()->isAnyComplexType())
1454      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1455    else
1456      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1457    return LV;
1458  }
1459  }
1460}
1461
1462LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1463  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1464                        E->getType());
1465}
1466
1467LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1468  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1469                        E->getType());
1470}
1471
1472
1473LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1474  switch (E->getIdentType()) {
1475  default:
1476    return EmitUnsupportedLValue(E, "predefined expression");
1477
1478  case PredefinedExpr::Func:
1479  case PredefinedExpr::Function:
1480  case PredefinedExpr::PrettyFunction: {
1481    unsigned Type = E->getIdentType();
1482    std::string GlobalVarName;
1483
1484    switch (Type) {
1485    default: assert(0 && "Invalid type");
1486    case PredefinedExpr::Func:
1487      GlobalVarName = "__func__.";
1488      break;
1489    case PredefinedExpr::Function:
1490      GlobalVarName = "__FUNCTION__.";
1491      break;
1492    case PredefinedExpr::PrettyFunction:
1493      GlobalVarName = "__PRETTY_FUNCTION__.";
1494      break;
1495    }
1496
1497    StringRef FnName = CurFn->getName();
1498    if (FnName.startswith("\01"))
1499      FnName = FnName.substr(1);
1500    GlobalVarName += FnName;
1501
1502    const Decl *CurDecl = CurCodeDecl;
1503    if (CurDecl == 0)
1504      CurDecl = getContext().getTranslationUnitDecl();
1505
1506    std::string FunctionName =
1507        (isa<BlockDecl>(CurDecl)
1508         ? FnName.str()
1509         : PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl));
1510
1511    llvm::Constant *C =
1512      CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1513    return MakeAddrLValue(C, E->getType());
1514  }
1515  }
1516}
1517
1518llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1519  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1520
1521  // If we are not optimzing, don't collapse all calls to trap in the function
1522  // to the same call, that way, in the debugger they can see which operation
1523  // did in fact fail.  If we are optimizing, we collapse all calls to trap down
1524  // to just one per function to save on codesize.
1525  if (GCO.OptimizationLevel && TrapBB)
1526    return TrapBB;
1527
1528  llvm::BasicBlock *Cont = 0;
1529  if (HaveInsertPoint()) {
1530    Cont = createBasicBlock("cont");
1531    EmitBranch(Cont);
1532  }
1533  TrapBB = createBasicBlock("trap");
1534  EmitBlock(TrapBB);
1535
1536  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap);
1537  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1538  TrapCall->setDoesNotReturn();
1539  TrapCall->setDoesNotThrow();
1540  Builder.CreateUnreachable();
1541
1542  if (Cont)
1543    EmitBlock(Cont);
1544  return TrapBB;
1545}
1546
1547/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
1548/// array to pointer, return the array subexpression.
1549static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
1550  // If this isn't just an array->pointer decay, bail out.
1551  const CastExpr *CE = dyn_cast<CastExpr>(E);
1552  if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
1553    return 0;
1554
1555  // If this is a decay from variable width array, bail out.
1556  const Expr *SubExpr = CE->getSubExpr();
1557  if (SubExpr->getType()->isVariableArrayType())
1558    return 0;
1559
1560  return SubExpr;
1561}
1562
1563LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1564  // The index must always be an integer, which is not an aggregate.  Emit it.
1565  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1566  QualType IdxTy  = E->getIdx()->getType();
1567  bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
1568
1569  // If the base is a vector type, then we are forming a vector element lvalue
1570  // with this subscript.
1571  if (E->getBase()->getType()->isVectorType()) {
1572    // Emit the vector as an lvalue to get its address.
1573    LValue LHS = EmitLValue(E->getBase());
1574    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1575    Idx = Builder.CreateIntCast(Idx, Int32Ty, IdxSigned, "vidx");
1576    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1577                                 E->getBase()->getType());
1578  }
1579
1580  // Extend or truncate the index type to 32 or 64-bits.
1581  if (Idx->getType() != IntPtrTy)
1582    Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
1583
1584  // FIXME: As llvm implements the object size checking, this can come out.
1585  if (CatchUndefined) {
1586    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())){
1587      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1588        if (ICE->getCastKind() == CK_ArrayToPointerDecay) {
1589          if (const ConstantArrayType *CAT
1590              = getContext().getAsConstantArrayType(DRE->getType())) {
1591            llvm::APInt Size = CAT->getSize();
1592            llvm::BasicBlock *Cont = createBasicBlock("cont");
1593            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1594                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1595                                 Cont, getTrapBB());
1596            EmitBlock(Cont);
1597          }
1598        }
1599      }
1600    }
1601  }
1602
1603  // We know that the pointer points to a type of the correct size, unless the
1604  // size is a VLA or Objective-C interface.
1605  llvm::Value *Address = 0;
1606  unsigned ArrayAlignment = 0;
1607  if (const VariableArrayType *vla =
1608        getContext().getAsVariableArrayType(E->getType())) {
1609    // The base must be a pointer, which is not an aggregate.  Emit
1610    // it.  It needs to be emitted first in case it's what captures
1611    // the VLA bounds.
1612    Address = EmitScalarExpr(E->getBase());
1613
1614    // The element count here is the total number of non-VLA elements.
1615    llvm::Value *numElements = getVLASize(vla).first;
1616
1617    // Effectively, the multiply by the VLA size is part of the GEP.
1618    // GEP indexes are signed, and scaling an index isn't permitted to
1619    // signed-overflow, so we use the same semantics for our explicit
1620    // multiply.  We suppress this if overflow is not undefined behavior.
1621    if (getLangOptions().isSignedOverflowDefined()) {
1622      Idx = Builder.CreateMul(Idx, numElements);
1623      Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1624    } else {
1625      Idx = Builder.CreateNSWMul(Idx, numElements);
1626      Address = Builder.CreateInBoundsGEP(Address, Idx, "arrayidx");
1627    }
1628  } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
1629    // Indexing over an interface, as in "NSString *P; P[4];"
1630    llvm::Value *InterfaceSize =
1631      llvm::ConstantInt::get(Idx->getType(),
1632          getContext().getTypeSizeInChars(OIT).getQuantity());
1633
1634    Idx = Builder.CreateMul(Idx, InterfaceSize);
1635
1636    // The base must be a pointer, which is not an aggregate.  Emit it.
1637    llvm::Value *Base = EmitScalarExpr(E->getBase());
1638    Address = EmitCastToVoidPtr(Base);
1639    Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1640    Address = Builder.CreateBitCast(Address, Base->getType());
1641  } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
1642    // If this is A[i] where A is an array, the frontend will have decayed the
1643    // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
1644    // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
1645    // "gep x, i" here.  Emit one "gep A, 0, i".
1646    assert(Array->getType()->isArrayType() &&
1647           "Array to pointer decay must have array source type!");
1648    LValue ArrayLV = EmitLValue(Array);
1649    llvm::Value *ArrayPtr = ArrayLV.getAddress();
1650    llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
1651    llvm::Value *Args[] = { Zero, Idx };
1652
1653    // Propagate the alignment from the array itself to the result.
1654    ArrayAlignment = ArrayLV.getAlignment();
1655
1656    if (getContext().getLangOptions().isSignedOverflowDefined())
1657      Address = Builder.CreateGEP(ArrayPtr, Args, "arrayidx");
1658    else
1659      Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, "arrayidx");
1660  } else {
1661    // The base must be a pointer, which is not an aggregate.  Emit it.
1662    llvm::Value *Base = EmitScalarExpr(E->getBase());
1663    if (getContext().getLangOptions().isSignedOverflowDefined())
1664      Address = Builder.CreateGEP(Base, Idx, "arrayidx");
1665    else
1666      Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1667  }
1668
1669  QualType T = E->getBase()->getType()->getPointeeType();
1670  assert(!T.isNull() &&
1671         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1672
1673  // Limit the alignment to that of the result type.
1674  if (ArrayAlignment) {
1675    unsigned Align = getContext().getTypeAlignInChars(T).getQuantity();
1676    ArrayAlignment = std::min(Align, ArrayAlignment);
1677  }
1678
1679  LValue LV = MakeAddrLValue(Address, T, ArrayAlignment);
1680  LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
1681
1682  if (getContext().getLangOptions().ObjC1 &&
1683      getContext().getLangOptions().getGC() != LangOptions::NonGC) {
1684    LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1685    setObjCGCLValueClass(getContext(), E, LV);
1686  }
1687  return LV;
1688}
1689
1690static
1691llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1692                                       SmallVector<unsigned, 4> &Elts) {
1693  SmallVector<llvm::Constant*, 4> CElts;
1694
1695  llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1696  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1697    CElts.push_back(llvm::ConstantInt::get(Int32Ty, Elts[i]));
1698
1699  return llvm::ConstantVector::get(CElts);
1700}
1701
1702LValue CodeGenFunction::
1703EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1704  // Emit the base vector as an l-value.
1705  LValue Base;
1706
1707  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1708  if (E->isArrow()) {
1709    // If it is a pointer to a vector, emit the address and form an lvalue with
1710    // it.
1711    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1712    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1713    Base = MakeAddrLValue(Ptr, PT->getPointeeType());
1714    Base.getQuals().removeObjCGCAttr();
1715  } else if (E->getBase()->isGLValue()) {
1716    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1717    // emit the base as an lvalue.
1718    assert(E->getBase()->getType()->isVectorType());
1719    Base = EmitLValue(E->getBase());
1720  } else {
1721    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1722    assert(E->getBase()->getType()->isVectorType() &&
1723           "Result must be a vector");
1724    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1725
1726    // Store the vector to memory (because LValue wants an address).
1727    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1728    Builder.CreateStore(Vec, VecMem);
1729    Base = MakeAddrLValue(VecMem, E->getBase()->getType());
1730  }
1731
1732  QualType type =
1733    E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers());
1734
1735  // Encode the element access list into a vector of unsigned indices.
1736  SmallVector<unsigned, 4> Indices;
1737  E->getEncodedElementAccess(Indices);
1738
1739  if (Base.isSimple()) {
1740    llvm::Constant *CV = GenerateConstantVector(getLLVMContext(), Indices);
1741    return LValue::MakeExtVectorElt(Base.getAddress(), CV, type);
1742  }
1743  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1744
1745  llvm::Constant *BaseElts = Base.getExtVectorElts();
1746  SmallVector<llvm::Constant *, 4> CElts;
1747
1748  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1749    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1750      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1751    else
1752      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1753  }
1754  llvm::Constant *CV = llvm::ConstantVector::get(CElts);
1755  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV, type);
1756}
1757
1758LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1759  bool isNonGC = false;
1760  Expr *BaseExpr = E->getBase();
1761  llvm::Value *BaseValue = NULL;
1762  Qualifiers BaseQuals;
1763
1764  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1765  if (E->isArrow()) {
1766    BaseValue = EmitScalarExpr(BaseExpr);
1767    const PointerType *PTy =
1768      BaseExpr->getType()->getAs<PointerType>();
1769    BaseQuals = PTy->getPointeeType().getQualifiers();
1770  } else {
1771    LValue BaseLV = EmitLValue(BaseExpr);
1772    if (BaseLV.isNonGC())
1773      isNonGC = true;
1774    // FIXME: this isn't right for bitfields.
1775    BaseValue = BaseLV.getAddress();
1776    QualType BaseTy = BaseExpr->getType();
1777    BaseQuals = BaseTy.getQualifiers();
1778  }
1779
1780  NamedDecl *ND = E->getMemberDecl();
1781  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1782    LValue LV = EmitLValueForField(BaseValue, Field,
1783                                   BaseQuals.getCVRQualifiers());
1784    LV.setNonGC(isNonGC);
1785    setObjCGCLValueClass(getContext(), E, LV);
1786    return LV;
1787  }
1788
1789  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1790    return EmitGlobalVarDeclLValue(*this, E, VD);
1791
1792  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1793    return EmitFunctionDeclLValue(*this, E, FD);
1794
1795  assert(false && "Unhandled member declaration!");
1796  return LValue();
1797}
1798
1799LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
1800                                              const FieldDecl *Field,
1801                                              unsigned CVRQualifiers) {
1802  const CGRecordLayout &RL =
1803    CGM.getTypes().getCGRecordLayout(Field->getParent());
1804  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1805  return LValue::MakeBitfield(BaseValue, Info,
1806                          Field->getType().withCVRQualifiers(CVRQualifiers));
1807}
1808
1809/// EmitLValueForAnonRecordField - Given that the field is a member of
1810/// an anonymous struct or union buried inside a record, and given
1811/// that the base value is a pointer to the enclosing record, derive
1812/// an lvalue for the ultimate field.
1813LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
1814                                             const IndirectFieldDecl *Field,
1815                                                     unsigned CVRQualifiers) {
1816  IndirectFieldDecl::chain_iterator I = Field->chain_begin(),
1817    IEnd = Field->chain_end();
1818  while (true) {
1819    LValue LV = EmitLValueForField(BaseValue, cast<FieldDecl>(*I),
1820                                   CVRQualifiers);
1821    if (++I == IEnd) return LV;
1822
1823    assert(LV.isSimple());
1824    BaseValue = LV.getAddress();
1825    CVRQualifiers |= LV.getVRQualifiers();
1826  }
1827}
1828
1829LValue CodeGenFunction::EmitLValueForField(llvm::Value *baseAddr,
1830                                           const FieldDecl *field,
1831                                           unsigned cvr) {
1832  if (field->isBitField())
1833    return EmitLValueForBitfield(baseAddr, field, cvr);
1834
1835  const RecordDecl *rec = field->getParent();
1836  QualType type = field->getType();
1837
1838  bool mayAlias = rec->hasAttr<MayAliasAttr>();
1839
1840  llvm::Value *addr = baseAddr;
1841  if (rec->isUnion()) {
1842    // For unions, there is no pointer adjustment.
1843    assert(!type->isReferenceType() && "union has reference member");
1844  } else {
1845    // For structs, we GEP to the field that the record layout suggests.
1846    unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
1847    addr = Builder.CreateStructGEP(addr, idx, field->getName());
1848
1849    // If this is a reference field, load the reference right now.
1850    if (const ReferenceType *refType = type->getAs<ReferenceType>()) {
1851      llvm::LoadInst *load = Builder.CreateLoad(addr, "ref");
1852      if (cvr & Qualifiers::Volatile) load->setVolatile(true);
1853
1854      if (CGM.shouldUseTBAA()) {
1855        llvm::MDNode *tbaa;
1856        if (mayAlias)
1857          tbaa = CGM.getTBAAInfo(getContext().CharTy);
1858        else
1859          tbaa = CGM.getTBAAInfo(type);
1860        CGM.DecorateInstruction(load, tbaa);
1861      }
1862
1863      addr = load;
1864      mayAlias = false;
1865      type = refType->getPointeeType();
1866      cvr = 0; // qualifiers don't recursively apply to referencee
1867    }
1868  }
1869
1870  // Make sure that the address is pointing to the right type.  This is critical
1871  // for both unions and structs.  A union needs a bitcast, a struct element
1872  // will need a bitcast if the LLVM type laid out doesn't match the desired
1873  // type.
1874  addr = EmitBitCastOfLValueToProperType(*this, addr,
1875                                         CGM.getTypes().ConvertTypeForMem(type),
1876                                         field->getName());
1877
1878  if (field->hasAttr<AnnotateAttr>())
1879    addr = EmitFieldAnnotations(field, addr);
1880
1881  unsigned alignment = getContext().getDeclAlign(field).getQuantity();
1882  LValue LV = MakeAddrLValue(addr, type, alignment);
1883  LV.getQuals().addCVRQualifiers(cvr);
1884
1885  // __weak attribute on a field is ignored.
1886  if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
1887    LV.getQuals().removeObjCGCAttr();
1888
1889  // Fields of may_alias structs act like 'char' for TBAA purposes.
1890  // FIXME: this should get propagated down through anonymous structs
1891  // and unions.
1892  if (mayAlias && LV.getTBAAInfo())
1893    LV.setTBAAInfo(CGM.getTBAAInfo(getContext().CharTy));
1894
1895  return LV;
1896}
1897
1898LValue
1899CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value *BaseValue,
1900                                                  const FieldDecl *Field,
1901                                                  unsigned CVRQualifiers) {
1902  QualType FieldType = Field->getType();
1903
1904  if (!FieldType->isReferenceType())
1905    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1906
1907  const CGRecordLayout &RL =
1908    CGM.getTypes().getCGRecordLayout(Field->getParent());
1909  unsigned idx = RL.getLLVMFieldNo(Field);
1910  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1911  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1912
1913
1914  // Make sure that the address is pointing to the right type.  This is critical
1915  // for both unions and structs.  A union needs a bitcast, a struct element
1916  // will need a bitcast if the LLVM type laid out doesn't match the desired
1917  // type.
1918  llvm::Type *llvmType = ConvertTypeForMem(FieldType);
1919  unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
1920  V = Builder.CreateBitCast(V, llvmType->getPointerTo(AS));
1921
1922  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1923  return MakeAddrLValue(V, FieldType, Alignment);
1924}
1925
1926LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
1927  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1928  const Expr *InitExpr = E->getInitializer();
1929  LValue Result = MakeAddrLValue(DeclPtr, E->getType());
1930
1931  EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
1932                   /*Init*/ true);
1933
1934  return Result;
1935}
1936
1937LValue CodeGenFunction::
1938EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
1939  if (!expr->isGLValue()) {
1940    // ?: here should be an aggregate.
1941    assert((hasAggregateLLVMType(expr->getType()) &&
1942            !expr->getType()->isAnyComplexType()) &&
1943           "Unexpected conditional operator!");
1944    return EmitAggExprToLValue(expr);
1945  }
1946
1947  const Expr *condExpr = expr->getCond();
1948  bool CondExprBool;
1949  if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
1950    const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr();
1951    if (!CondExprBool) std::swap(live, dead);
1952
1953    if (!ContainsLabel(dead))
1954      return EmitLValue(live);
1955  }
1956
1957  OpaqueValueMapping binding(*this, expr);
1958
1959  llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
1960  llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
1961  llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
1962
1963  ConditionalEvaluation eval(*this);
1964  EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock);
1965
1966  // Any temporaries created here are conditional.
1967  EmitBlock(lhsBlock);
1968  eval.begin(*this);
1969  LValue lhs = EmitLValue(expr->getTrueExpr());
1970  eval.end(*this);
1971
1972  if (!lhs.isSimple())
1973    return EmitUnsupportedLValue(expr, "conditional operator");
1974
1975  lhsBlock = Builder.GetInsertBlock();
1976  Builder.CreateBr(contBlock);
1977
1978  // Any temporaries created here are conditional.
1979  EmitBlock(rhsBlock);
1980  eval.begin(*this);
1981  LValue rhs = EmitLValue(expr->getFalseExpr());
1982  eval.end(*this);
1983  if (!rhs.isSimple())
1984    return EmitUnsupportedLValue(expr, "conditional operator");
1985  rhsBlock = Builder.GetInsertBlock();
1986
1987  EmitBlock(contBlock);
1988
1989  llvm::PHINode *phi = Builder.CreatePHI(lhs.getAddress()->getType(), 2,
1990                                         "cond-lvalue");
1991  phi->addIncoming(lhs.getAddress(), lhsBlock);
1992  phi->addIncoming(rhs.getAddress(), rhsBlock);
1993  return MakeAddrLValue(phi, expr->getType());
1994}
1995
1996/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1997/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1998/// otherwise if a cast is needed by the code generator in an lvalue context,
1999/// then it must mean that we need the address of an aggregate in order to
2000/// access one of its fields.  This can happen for all the reasons that casts
2001/// are permitted with aggregate result, including noop aggregate casts, and
2002/// cast from scalar to union.
2003LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
2004  switch (E->getCastKind()) {
2005  case CK_ToVoid:
2006    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
2007
2008  case CK_Dependent:
2009    llvm_unreachable("dependent cast kind in IR gen!");
2010
2011  case CK_GetObjCProperty: {
2012    LValue LV = EmitLValue(E->getSubExpr());
2013    assert(LV.isPropertyRef());
2014    RValue RV = EmitLoadOfPropertyRefLValue(LV);
2015
2016    // Property is an aggregate r-value.
2017    if (RV.isAggregate()) {
2018      return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2019    }
2020
2021    // Implicit property returns an l-value.
2022    assert(RV.isScalar());
2023    return MakeAddrLValue(RV.getScalarVal(), E->getSubExpr()->getType());
2024  }
2025
2026  case CK_NoOp:
2027  case CK_LValueToRValue:
2028    if (!E->getSubExpr()->Classify(getContext()).isPRValue()
2029        || E->getType()->isRecordType())
2030      return EmitLValue(E->getSubExpr());
2031    // Fall through to synthesize a temporary.
2032
2033  case CK_BitCast:
2034  case CK_ArrayToPointerDecay:
2035  case CK_FunctionToPointerDecay:
2036  case CK_NullToMemberPointer:
2037  case CK_NullToPointer:
2038  case CK_IntegralToPointer:
2039  case CK_PointerToIntegral:
2040  case CK_PointerToBoolean:
2041  case CK_VectorSplat:
2042  case CK_IntegralCast:
2043  case CK_IntegralToBoolean:
2044  case CK_IntegralToFloating:
2045  case CK_FloatingToIntegral:
2046  case CK_FloatingToBoolean:
2047  case CK_FloatingCast:
2048  case CK_FloatingRealToComplex:
2049  case CK_FloatingComplexToReal:
2050  case CK_FloatingComplexToBoolean:
2051  case CK_FloatingComplexCast:
2052  case CK_FloatingComplexToIntegralComplex:
2053  case CK_IntegralRealToComplex:
2054  case CK_IntegralComplexToReal:
2055  case CK_IntegralComplexToBoolean:
2056  case CK_IntegralComplexCast:
2057  case CK_IntegralComplexToFloatingComplex:
2058  case CK_DerivedToBaseMemberPointer:
2059  case CK_BaseToDerivedMemberPointer:
2060  case CK_MemberPointerToBoolean:
2061  case CK_AnyPointerToBlockPointerCast:
2062  case CK_ARCProduceObject:
2063  case CK_ARCConsumeObject:
2064  case CK_ARCReclaimReturnedObject:
2065  case CK_ARCExtendBlockObject: {
2066    // These casts only produce lvalues when we're binding a reference to a
2067    // temporary realized from a (converted) pure rvalue. Emit the expression
2068    // as a value, copy it into a temporary, and return an lvalue referring to
2069    // that temporary.
2070    llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
2071    EmitAnyExprToMem(E, V, E->getType().getQualifiers(), false);
2072    return MakeAddrLValue(V, E->getType());
2073  }
2074
2075  case CK_Dynamic: {
2076    LValue LV = EmitLValue(E->getSubExpr());
2077    llvm::Value *V = LV.getAddress();
2078    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
2079    return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
2080  }
2081
2082  case CK_ConstructorConversion:
2083  case CK_UserDefinedConversion:
2084  case CK_CPointerToObjCPointerCast:
2085  case CK_BlockPointerToObjCPointerCast:
2086    return EmitLValue(E->getSubExpr());
2087
2088  case CK_UncheckedDerivedToBase:
2089  case CK_DerivedToBase: {
2090    const RecordType *DerivedClassTy =
2091      E->getSubExpr()->getType()->getAs<RecordType>();
2092    CXXRecordDecl *DerivedClassDecl =
2093      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2094
2095    LValue LV = EmitLValue(E->getSubExpr());
2096    llvm::Value *This = LV.getAddress();
2097
2098    // Perform the derived-to-base conversion
2099    llvm::Value *Base =
2100      GetAddressOfBaseClass(This, DerivedClassDecl,
2101                            E->path_begin(), E->path_end(),
2102                            /*NullCheckValue=*/false);
2103
2104    return MakeAddrLValue(Base, E->getType());
2105  }
2106  case CK_ToUnion:
2107    return EmitAggExprToLValue(E);
2108  case CK_BaseToDerived: {
2109    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
2110    CXXRecordDecl *DerivedClassDecl =
2111      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2112
2113    LValue LV = EmitLValue(E->getSubExpr());
2114
2115    // Perform the base-to-derived conversion
2116    llvm::Value *Derived =
2117      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
2118                               E->path_begin(), E->path_end(),
2119                               /*NullCheckValue=*/false);
2120
2121    return MakeAddrLValue(Derived, E->getType());
2122  }
2123  case CK_LValueBitCast: {
2124    // This must be a reinterpret_cast (or c-style equivalent).
2125    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
2126
2127    LValue LV = EmitLValue(E->getSubExpr());
2128    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2129                                           ConvertType(CE->getTypeAsWritten()));
2130    return MakeAddrLValue(V, E->getType());
2131  }
2132  case CK_ObjCObjectLValueCast: {
2133    LValue LV = EmitLValue(E->getSubExpr());
2134    QualType ToType = getContext().getLValueReferenceType(E->getType());
2135    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2136                                           ConvertType(ToType));
2137    return MakeAddrLValue(V, E->getType());
2138  }
2139  }
2140
2141  llvm_unreachable("Unhandled lvalue cast kind?");
2142}
2143
2144LValue CodeGenFunction::EmitNullInitializationLValue(
2145                                              const CXXScalarValueInitExpr *E) {
2146  QualType Ty = E->getType();
2147  LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
2148  EmitNullInitialization(LV.getAddress(), Ty);
2149  return LV;
2150}
2151
2152LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
2153  assert(e->isGLValue() || e->getType()->isRecordType());
2154  return getOpaqueLValueMapping(e);
2155}
2156
2157LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
2158                                           const MaterializeTemporaryExpr *E) {
2159  RValue RV = EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
2160  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2161}
2162
2163
2164//===--------------------------------------------------------------------===//
2165//                             Expression Emission
2166//===--------------------------------------------------------------------===//
2167
2168RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
2169                                     ReturnValueSlot ReturnValue) {
2170  if (CGDebugInfo *DI = getDebugInfo()) {
2171    DI->setLocation(E->getLocStart());
2172    DI->UpdateLineDirectiveRegion(Builder);
2173    DI->EmitStopPoint(Builder);
2174  }
2175
2176  // Builtins never have block type.
2177  if (E->getCallee()->getType()->isBlockPointerType())
2178    return EmitBlockCallExpr(E, ReturnValue);
2179
2180  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
2181    return EmitCXXMemberCallExpr(CE, ReturnValue);
2182
2183  const Decl *TargetDecl = E->getCalleeDecl();
2184  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl)) {
2185    if (unsigned builtinID = FD->getBuiltinID())
2186      return EmitBuiltinExpr(FD, builtinID, E);
2187  }
2188
2189  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
2190    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
2191      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
2192
2193  if (const CXXPseudoDestructorExpr *PseudoDtor
2194          = dyn_cast<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
2195    QualType DestroyedType = PseudoDtor->getDestroyedType();
2196    if (getContext().getLangOptions().ObjCAutoRefCount &&
2197        DestroyedType->isObjCLifetimeType() &&
2198        (DestroyedType.getObjCLifetime() == Qualifiers::OCL_Strong ||
2199         DestroyedType.getObjCLifetime() == Qualifiers::OCL_Weak)) {
2200      // Automatic Reference Counting:
2201      //   If the pseudo-expression names a retainable object with weak or
2202      //   strong lifetime, the object shall be released.
2203      Expr *BaseExpr = PseudoDtor->getBase();
2204      llvm::Value *BaseValue = NULL;
2205      Qualifiers BaseQuals;
2206
2207      // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
2208      if (PseudoDtor->isArrow()) {
2209        BaseValue = EmitScalarExpr(BaseExpr);
2210        const PointerType *PTy = BaseExpr->getType()->getAs<PointerType>();
2211        BaseQuals = PTy->getPointeeType().getQualifiers();
2212      } else {
2213        LValue BaseLV = EmitLValue(BaseExpr);
2214        BaseValue = BaseLV.getAddress();
2215        QualType BaseTy = BaseExpr->getType();
2216        BaseQuals = BaseTy.getQualifiers();
2217      }
2218
2219      switch (PseudoDtor->getDestroyedType().getObjCLifetime()) {
2220      case Qualifiers::OCL_None:
2221      case Qualifiers::OCL_ExplicitNone:
2222      case Qualifiers::OCL_Autoreleasing:
2223        break;
2224
2225      case Qualifiers::OCL_Strong:
2226        EmitARCRelease(Builder.CreateLoad(BaseValue,
2227                          PseudoDtor->getDestroyedType().isVolatileQualified()),
2228                       /*precise*/ true);
2229        break;
2230
2231      case Qualifiers::OCL_Weak:
2232        EmitARCDestroyWeak(BaseValue);
2233        break;
2234      }
2235    } else {
2236      // C++ [expr.pseudo]p1:
2237      //   The result shall only be used as the operand for the function call
2238      //   operator (), and the result of such a call has type void. The only
2239      //   effect is the evaluation of the postfix-expression before the dot or
2240      //   arrow.
2241      EmitScalarExpr(E->getCallee());
2242    }
2243
2244    return RValue::get(0);
2245  }
2246
2247  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
2248  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
2249                  E->arg_begin(), E->arg_end(), TargetDecl);
2250}
2251
2252LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
2253  // Comma expressions just emit their LHS then their RHS as an l-value.
2254  if (E->getOpcode() == BO_Comma) {
2255    EmitIgnoredExpr(E->getLHS());
2256    EnsureInsertPoint();
2257    return EmitLValue(E->getRHS());
2258  }
2259
2260  if (E->getOpcode() == BO_PtrMemD ||
2261      E->getOpcode() == BO_PtrMemI)
2262    return EmitPointerToDataMemberBinaryExpr(E);
2263
2264  assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
2265
2266  // Note that in all of these cases, __block variables need the RHS
2267  // evaluated first just in case the variable gets moved by the RHS.
2268
2269  if (!hasAggregateLLVMType(E->getType())) {
2270    switch (E->getLHS()->getType().getObjCLifetime()) {
2271    case Qualifiers::OCL_Strong:
2272      return EmitARCStoreStrong(E, /*ignored*/ false).first;
2273
2274    case Qualifiers::OCL_Autoreleasing:
2275      return EmitARCStoreAutoreleasing(E).first;
2276
2277    // No reason to do any of these differently.
2278    case Qualifiers::OCL_None:
2279    case Qualifiers::OCL_ExplicitNone:
2280    case Qualifiers::OCL_Weak:
2281      break;
2282    }
2283
2284    RValue RV = EmitAnyExpr(E->getRHS());
2285    LValue LV = EmitLValue(E->getLHS());
2286    EmitStoreThroughLValue(RV, LV);
2287    return LV;
2288  }
2289
2290  if (E->getType()->isAnyComplexType())
2291    return EmitComplexAssignmentLValue(E);
2292
2293  return EmitAggExprToLValue(E);
2294}
2295
2296LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
2297  RValue RV = EmitCallExpr(E);
2298
2299  if (!RV.isScalar())
2300    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2301
2302  assert(E->getCallReturnType()->isReferenceType() &&
2303         "Can't have a scalar return unless the return type is a "
2304         "reference type!");
2305
2306  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2307}
2308
2309LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
2310  // FIXME: This shouldn't require another copy.
2311  return EmitAggExprToLValue(E);
2312}
2313
2314LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
2315  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
2316         && "binding l-value to type which needs a temporary");
2317  AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
2318  EmitCXXConstructExpr(E, Slot);
2319  return MakeAddrLValue(Slot.getAddr(), E->getType());
2320}
2321
2322LValue
2323CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
2324  return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
2325}
2326
2327LValue
2328CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
2329  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
2330  Slot.setExternallyDestructed();
2331  EmitAggExpr(E->getSubExpr(), Slot);
2332  EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
2333  return MakeAddrLValue(Slot.getAddr(), E->getType());
2334}
2335
2336LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
2337  RValue RV = EmitObjCMessageExpr(E);
2338
2339  if (!RV.isScalar())
2340    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2341
2342  assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
2343         "Can't have a scalar return unless the return type is a "
2344         "reference type!");
2345
2346  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2347}
2348
2349LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
2350  llvm::Value *V =
2351    CGM.getObjCRuntime().GetSelector(Builder, E->getSelector(), true);
2352  return MakeAddrLValue(V, E->getType());
2353}
2354
2355llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
2356                                             const ObjCIvarDecl *Ivar) {
2357  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
2358}
2359
2360LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
2361                                          llvm::Value *BaseValue,
2362                                          const ObjCIvarDecl *Ivar,
2363                                          unsigned CVRQualifiers) {
2364  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
2365                                                   Ivar, CVRQualifiers);
2366}
2367
2368LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
2369  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
2370  llvm::Value *BaseValue = 0;
2371  const Expr *BaseExpr = E->getBase();
2372  Qualifiers BaseQuals;
2373  QualType ObjectTy;
2374  if (E->isArrow()) {
2375    BaseValue = EmitScalarExpr(BaseExpr);
2376    ObjectTy = BaseExpr->getType()->getPointeeType();
2377    BaseQuals = ObjectTy.getQualifiers();
2378  } else {
2379    LValue BaseLV = EmitLValue(BaseExpr);
2380    // FIXME: this isn't right for bitfields.
2381    BaseValue = BaseLV.getAddress();
2382    ObjectTy = BaseExpr->getType();
2383    BaseQuals = ObjectTy.getQualifiers();
2384  }
2385
2386  LValue LV =
2387    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
2388                      BaseQuals.getCVRQualifiers());
2389  setObjCGCLValueClass(getContext(), E, LV);
2390  return LV;
2391}
2392
2393LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
2394  // Can only get l-value for message expression returning aggregate type
2395  RValue RV = EmitAnyExprToTemp(E);
2396  return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2397}
2398
2399RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
2400                                 ReturnValueSlot ReturnValue,
2401                                 CallExpr::const_arg_iterator ArgBeg,
2402                                 CallExpr::const_arg_iterator ArgEnd,
2403                                 const Decl *TargetDecl) {
2404  // Get the actual function type. The callee type will always be a pointer to
2405  // function type or a block pointer type.
2406  assert(CalleeType->isFunctionPointerType() &&
2407         "Call must have function pointer type!");
2408
2409  CalleeType = getContext().getCanonicalType(CalleeType);
2410
2411  const FunctionType *FnType
2412    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
2413
2414  CallArgList Args;
2415  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
2416
2417  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
2418                  Callee, ReturnValue, Args, TargetDecl);
2419}
2420
2421LValue CodeGenFunction::
2422EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
2423  llvm::Value *BaseV;
2424  if (E->getOpcode() == BO_PtrMemI)
2425    BaseV = EmitScalarExpr(E->getLHS());
2426  else
2427    BaseV = EmitLValue(E->getLHS()).getAddress();
2428
2429  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
2430
2431  const MemberPointerType *MPT
2432    = E->getRHS()->getType()->getAs<MemberPointerType>();
2433
2434  llvm::Value *AddV =
2435    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
2436
2437  return MakeAddrLValue(AddV, MPT->getPointeeType());
2438}
2439