CGExpr.cpp revision 91a5755ad73c5dc1dfb167e448fdd74e75a6df56 
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  const llvm::PointerType *destType = Int8PtrTy;
38  if (addressSpace)
39    destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
40
41  if (value->getType() == destType) return value;
42  return Builder.CreateBitCast(value, destType);
43}
44
45/// CreateTempAlloca - This creates a alloca and inserts it into the entry
46/// block.
47llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
48                                                    const llvm::Twine &Name) {
49  if (!Builder.isNamePreserving())
50    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
51  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
52}
53
54void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
55                                     llvm::Value *Init) {
56  llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
57  llvm::BasicBlock *Block = AllocaInsertPt->getParent();
58  Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
59}
60
61llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
62                                                const llvm::Twine &Name) {
63  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
64  // FIXME: Should we prefer the preferred type alignment here?
65  CharUnits Align = getContext().getTypeAlignInChars(Ty);
66  Alloc->setAlignment(Align.getQuantity());
67  return Alloc;
68}
69
70llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
71                                                 const llvm::Twine &Name) {
72  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
73  // FIXME: Should we prefer the preferred type alignment here?
74  CharUnits Align = getContext().getTypeAlignInChars(Ty);
75  Alloc->setAlignment(Align.getQuantity());
76  return Alloc;
77}
78
79/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
80/// expression and compare the result against zero, returning an Int1Ty value.
81llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
82  if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
83    llvm::Value *MemPtr = EmitScalarExpr(E);
84    return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT);
85  }
86
87  QualType BoolTy = getContext().BoolTy;
88  if (!E->getType()->isAnyComplexType())
89    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
90
91  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
92}
93
94/// EmitIgnoredExpr - Emit code to compute the specified expression,
95/// ignoring the result.
96void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
97  if (E->isRValue())
98    return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
99
100  // Just emit it as an l-value and drop the result.
101  EmitLValue(E);
102}
103
104/// EmitAnyExpr - Emit code to compute the specified expression which
105/// can have any type.  The result is returned as an RValue struct.
106/// If this is an aggregate expression, AggSlot indicates where the
107/// result should be returned.
108RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot AggSlot,
109                                    bool IgnoreResult) {
110  if (!hasAggregateLLVMType(E->getType()))
111    return RValue::get(EmitScalarExpr(E, IgnoreResult));
112  else if (E->getType()->isAnyComplexType())
113    return RValue::getComplex(EmitComplexExpr(E, IgnoreResult, IgnoreResult));
114
115  EmitAggExpr(E, AggSlot, IgnoreResult);
116  return AggSlot.asRValue();
117}
118
119/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
120/// always be accessible even if no aggregate location is provided.
121RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
122  AggValueSlot AggSlot = AggValueSlot::ignored();
123
124  if (hasAggregateLLVMType(E->getType()) &&
125      !E->getType()->isAnyComplexType())
126    AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
127  return EmitAnyExpr(E, AggSlot);
128}
129
130/// EmitAnyExprToMem - Evaluate an expression into a given memory
131/// location.
132void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
133                                       llvm::Value *Location,
134                                       Qualifiers Quals,
135                                       bool IsInit) {
136  if (E->getType()->isAnyComplexType())
137    EmitComplexExprIntoAddr(E, Location, Quals.hasVolatile());
138  else if (hasAggregateLLVMType(E->getType()))
139    EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals, IsInit));
140  else {
141    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
142    LValue LV = MakeAddrLValue(Location, E->getType());
143    EmitStoreThroughLValue(RV, LV);
144  }
145}
146
147namespace {
148/// \brief An adjustment to be made to the temporary created when emitting a
149/// reference binding, which accesses a particular subobject of that temporary.
150  struct SubobjectAdjustment {
151    enum { DerivedToBaseAdjustment, FieldAdjustment } Kind;
152
153    union {
154      struct {
155        const CastExpr *BasePath;
156        const CXXRecordDecl *DerivedClass;
157      } DerivedToBase;
158
159      FieldDecl *Field;
160    };
161
162    SubobjectAdjustment(const CastExpr *BasePath,
163                        const CXXRecordDecl *DerivedClass)
164      : Kind(DerivedToBaseAdjustment) {
165      DerivedToBase.BasePath = BasePath;
166      DerivedToBase.DerivedClass = DerivedClass;
167    }
168
169    SubobjectAdjustment(FieldDecl *Field)
170      : Kind(FieldAdjustment) {
171      this->Field = Field;
172    }
173  };
174}
175
176static llvm::Value *
177CreateReferenceTemporary(CodeGenFunction& CGF, QualType Type,
178                         const NamedDecl *InitializedDecl) {
179  if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
180    if (VD->hasGlobalStorage()) {
181      llvm::SmallString<256> Name;
182      llvm::raw_svector_ostream Out(Name);
183      CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Out);
184      Out.flush();
185
186      const llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
187
188      // Create the reference temporary.
189      llvm::GlobalValue *RefTemp =
190        new llvm::GlobalVariable(CGF.CGM.getModule(),
191                                 RefTempTy, /*isConstant=*/false,
192                                 llvm::GlobalValue::InternalLinkage,
193                                 llvm::Constant::getNullValue(RefTempTy),
194                                 Name.str());
195      return RefTemp;
196    }
197  }
198
199  return CGF.CreateMemTemp(Type, "ref.tmp");
200}
201
202static llvm::Value *
203EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
204                            llvm::Value *&ReferenceTemporary,
205                            const CXXDestructorDecl *&ReferenceTemporaryDtor,
206                            QualType &ObjCARCReferenceLifetimeType,
207                            const NamedDecl *InitializedDecl) {
208  // Look through expressions for materialized temporaries (for now).
209  if (const MaterializeTemporaryExpr *M
210                                      = dyn_cast<MaterializeTemporaryExpr>(E)) {
211    // Objective-C++ ARC:
212    //   If we are binding a reference to a temporary that has ownership, we
213    //   need to perform retain/release operations on the temporary.
214    if (CGF.getContext().getLangOptions().ObjCAutoRefCount &&
215        E->getType()->isObjCLifetimeType() &&
216        (E->getType().getObjCLifetime() == Qualifiers::OCL_Strong ||
217         E->getType().getObjCLifetime() == Qualifiers::OCL_Weak ||
218         E->getType().getObjCLifetime() == Qualifiers::OCL_Autoreleasing))
219      ObjCARCReferenceLifetimeType = E->getType();
220
221    E = M->GetTemporaryExpr();
222  }
223
224  if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
225    E = DAE->getExpr();
226
227  if (const ExprWithCleanups *TE = dyn_cast<ExprWithCleanups>(E)) {
228    CodeGenFunction::RunCleanupsScope Scope(CGF);
229
230    return EmitExprForReferenceBinding(CGF, TE->getSubExpr(),
231                                       ReferenceTemporary,
232                                       ReferenceTemporaryDtor,
233                                       ObjCARCReferenceLifetimeType,
234                                       InitializedDecl);
235  }
236
237  if (const ObjCPropertyRefExpr *PRE =
238      dyn_cast<ObjCPropertyRefExpr>(E->IgnoreParenImpCasts()))
239    if (PRE->getGetterResultType()->isReferenceType())
240      E = PRE;
241
242  RValue RV;
243  if (E->isGLValue()) {
244    // Emit the expression as an lvalue.
245    LValue LV = CGF.EmitLValue(E);
246    if (LV.isPropertyRef()) {
247      RV = CGF.EmitLoadOfPropertyRefLValue(LV);
248      return RV.getScalarVal();
249    }
250
251    if (LV.isSimple())
252      return LV.getAddress();
253
254    // We have to load the lvalue.
255    RV = CGF.EmitLoadOfLValue(LV);
256  } else {
257    if (!ObjCARCReferenceLifetimeType.isNull()) {
258      ReferenceTemporary = CreateReferenceTemporary(CGF,
259                                                  ObjCARCReferenceLifetimeType,
260                                                    InitializedDecl);
261
262
263      LValue RefTempDst = CGF.MakeAddrLValue(ReferenceTemporary,
264                                             ObjCARCReferenceLifetimeType);
265
266      CGF.EmitScalarInit(E, dyn_cast_or_null<ValueDecl>(InitializedDecl),
267                         RefTempDst, false);
268
269      bool ExtendsLifeOfTemporary = false;
270      if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
271        if (Var->extendsLifetimeOfTemporary())
272          ExtendsLifeOfTemporary = true;
273      } else if (InitializedDecl && isa<FieldDecl>(InitializedDecl)) {
274        ExtendsLifeOfTemporary = true;
275      }
276
277      if (!ExtendsLifeOfTemporary) {
278        // Since the lifetime of this temporary isn't going to be extended,
279        // we need to clean it up ourselves at the end of the full expression.
280        switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
281        case Qualifiers::OCL_None:
282        case Qualifiers::OCL_ExplicitNone:
283        case Qualifiers::OCL_Autoreleasing:
284          break;
285
286        case Qualifiers::OCL_Strong: {
287          assert(!ObjCARCReferenceLifetimeType->isArrayType());
288          CleanupKind cleanupKind = CGF.getARCCleanupKind();
289          CGF.pushDestroy(cleanupKind,
290                          ReferenceTemporary,
291                          ObjCARCReferenceLifetimeType,
292                          CodeGenFunction::destroyARCStrongImprecise,
293                          cleanupKind & EHCleanup);
294          break;
295        }
296
297        case Qualifiers::OCL_Weak:
298          assert(!ObjCARCReferenceLifetimeType->isArrayType());
299          CGF.pushDestroy(NormalAndEHCleanup,
300                          ReferenceTemporary,
301                          ObjCARCReferenceLifetimeType,
302                          CodeGenFunction::destroyARCWeak,
303                          /*useEHCleanupForArray*/ true);
304          break;
305        }
306
307        ObjCARCReferenceLifetimeType = QualType();
308      }
309
310      return ReferenceTemporary;
311    }
312
313    llvm::SmallVector<SubobjectAdjustment, 2> Adjustments;
314    while (true) {
315      E = E->IgnoreParens();
316
317      if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
318        if ((CE->getCastKind() == CK_DerivedToBase ||
319             CE->getCastKind() == CK_UncheckedDerivedToBase) &&
320            E->getType()->isRecordType()) {
321          E = CE->getSubExpr();
322          CXXRecordDecl *Derived
323            = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
324          Adjustments.push_back(SubobjectAdjustment(CE, Derived));
325          continue;
326        }
327
328        if (CE->getCastKind() == CK_NoOp) {
329          E = CE->getSubExpr();
330          continue;
331        }
332      } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
333        if (!ME->isArrow() && ME->getBase()->isRValue()) {
334          assert(ME->getBase()->getType()->isRecordType());
335          if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
336            E = ME->getBase();
337            Adjustments.push_back(SubobjectAdjustment(Field));
338            continue;
339          }
340        }
341      }
342
343      if (const OpaqueValueExpr *opaque = dyn_cast<OpaqueValueExpr>(E))
344        if (opaque->getType()->isRecordType())
345          return CGF.EmitOpaqueValueLValue(opaque).getAddress();
346
347      // Nothing changed.
348      break;
349    }
350
351    // Create a reference temporary if necessary.
352    AggValueSlot AggSlot = AggValueSlot::ignored();
353    if (CGF.hasAggregateLLVMType(E->getType()) &&
354        !E->getType()->isAnyComplexType()) {
355      ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
356                                                    InitializedDecl);
357      AggSlot = AggValueSlot::forAddr(ReferenceTemporary, Qualifiers(),
358                                      InitializedDecl != 0);
359    }
360
361    if (InitializedDecl) {
362      // Get the destructor for the reference temporary.
363      if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
364        CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
365        if (!ClassDecl->hasTrivialDestructor())
366          ReferenceTemporaryDtor = ClassDecl->getDestructor();
367      }
368    }
369
370    RV = CGF.EmitAnyExpr(E, AggSlot);
371
372    // Check if need to perform derived-to-base casts and/or field accesses, to
373    // get from the temporary object we created (and, potentially, for which we
374    // extended the lifetime) to the subobject we're binding the reference to.
375    if (!Adjustments.empty()) {
376      llvm::Value *Object = RV.getAggregateAddr();
377      for (unsigned I = Adjustments.size(); I != 0; --I) {
378        SubobjectAdjustment &Adjustment = Adjustments[I-1];
379        switch (Adjustment.Kind) {
380        case SubobjectAdjustment::DerivedToBaseAdjustment:
381          Object =
382              CGF.GetAddressOfBaseClass(Object,
383                                        Adjustment.DerivedToBase.DerivedClass,
384                              Adjustment.DerivedToBase.BasePath->path_begin(),
385                              Adjustment.DerivedToBase.BasePath->path_end(),
386                                        /*NullCheckValue=*/false);
387          break;
388
389        case SubobjectAdjustment::FieldAdjustment: {
390          LValue LV =
391            CGF.EmitLValueForField(Object, Adjustment.Field, 0);
392          if (LV.isSimple()) {
393            Object = LV.getAddress();
394            break;
395          }
396
397          // For non-simple lvalues, we actually have to create a copy of
398          // the object we're binding to.
399          QualType T = Adjustment.Field->getType().getNonReferenceType()
400                                                  .getUnqualifiedType();
401          Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
402          LValue TempLV = CGF.MakeAddrLValue(Object,
403                                             Adjustment.Field->getType());
404          CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV), TempLV);
405          break;
406        }
407
408        }
409      }
410
411      return Object;
412    }
413  }
414
415  if (RV.isAggregate())
416    return RV.getAggregateAddr();
417
418  // Create a temporary variable that we can bind the reference to.
419  ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
420                                                InitializedDecl);
421
422
423  unsigned Alignment =
424    CGF.getContext().getTypeAlignInChars(E->getType()).getQuantity();
425  if (RV.isScalar())
426    CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
427                          /*Volatile=*/false, Alignment, E->getType());
428  else
429    CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
430                           /*Volatile=*/false);
431  return ReferenceTemporary;
432}
433
434RValue
435CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
436                                            const NamedDecl *InitializedDecl) {
437  llvm::Value *ReferenceTemporary = 0;
438  const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
439  QualType ObjCARCReferenceLifetimeType;
440  llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
441                                                   ReferenceTemporaryDtor,
442                                                   ObjCARCReferenceLifetimeType,
443                                                   InitializedDecl);
444  if (!ReferenceTemporaryDtor && ObjCARCReferenceLifetimeType.isNull())
445    return RValue::get(Value);
446
447  // Make sure to call the destructor for the reference temporary.
448  const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl);
449  if (VD && VD->hasGlobalStorage()) {
450    if (ReferenceTemporaryDtor) {
451      llvm::Constant *DtorFn =
452        CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
453      EmitCXXGlobalDtorRegistration(DtorFn,
454                                    cast<llvm::Constant>(ReferenceTemporary));
455    } else {
456      assert(!ObjCARCReferenceLifetimeType.isNull());
457      // Note: We intentionally do not register a global "destructor" to
458      // release the object.
459    }
460
461    return RValue::get(Value);
462  }
463
464  if (ReferenceTemporaryDtor)
465    PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
466  else {
467    switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
468    case Qualifiers::OCL_None:
469      assert(0 && "Not a reference temporary that needs to be deallocated");
470    case Qualifiers::OCL_ExplicitNone:
471    case Qualifiers::OCL_Autoreleasing:
472      // Nothing to do.
473      break;
474
475    case Qualifiers::OCL_Strong: {
476      bool precise = VD && VD->hasAttr<ObjCPreciseLifetimeAttr>();
477      CleanupKind cleanupKind = getARCCleanupKind();
478      // This local is a GCC and MSVC compiler workaround.
479      Destroyer *destroyer = precise ? &destroyARCStrongPrecise :
480                                       &destroyARCStrongImprecise;
481      pushDestroy(cleanupKind, ReferenceTemporary, ObjCARCReferenceLifetimeType,
482                  *destroyer, cleanupKind & EHCleanup);
483      break;
484    }
485
486    case Qualifiers::OCL_Weak: {
487      // This local is a GCC and MSVC compiler workaround.
488      Destroyer *destroyer = &destroyARCWeak;
489      // __weak objects always get EH cleanups; otherwise, exceptions
490      // could cause really nasty crashes instead of mere leaks.
491      pushDestroy(NormalAndEHCleanup, ReferenceTemporary,
492                  ObjCARCReferenceLifetimeType, *destroyer, true);
493      break;
494    }
495    }
496  }
497
498  return RValue::get(Value);
499}
500
501
502/// getAccessedFieldNo - Given an encoded value and a result number, return the
503/// input field number being accessed.
504unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
505                                             const llvm::Constant *Elts) {
506  if (isa<llvm::ConstantAggregateZero>(Elts))
507    return 0;
508
509  return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
510}
511
512void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
513  if (!CatchUndefined)
514    return;
515
516  // This needs to be to the standard address space.
517  Address = Builder.CreateBitCast(Address, Int8PtrTy);
518
519  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, IntPtrTy);
520
521  // In time, people may want to control this and use a 1 here.
522  llvm::Value *Arg = Builder.getFalse();
523  llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
524  llvm::BasicBlock *Cont = createBasicBlock();
525  llvm::BasicBlock *Check = createBasicBlock();
526  llvm::Value *NegativeOne = llvm::ConstantInt::get(IntPtrTy, -1ULL);
527  Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
528
529  EmitBlock(Check);
530  Builder.CreateCondBr(Builder.CreateICmpUGE(C,
531                                        llvm::ConstantInt::get(IntPtrTy, Size)),
532                       Cont, getTrapBB());
533  EmitBlock(Cont);
534}
535
536
537CodeGenFunction::ComplexPairTy CodeGenFunction::
538EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
539                         bool isInc, bool isPre) {
540  ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
541                                            LV.isVolatileQualified());
542
543  llvm::Value *NextVal;
544  if (isa<llvm::IntegerType>(InVal.first->getType())) {
545    uint64_t AmountVal = isInc ? 1 : -1;
546    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
547
548    // Add the inc/dec to the real part.
549    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
550  } else {
551    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
552    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
553    if (!isInc)
554      FVal.changeSign();
555    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
556
557    // Add the inc/dec to the real part.
558    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
559  }
560
561  ComplexPairTy IncVal(NextVal, InVal.second);
562
563  // Store the updated result through the lvalue.
564  StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
565
566  // If this is a postinc, return the value read from memory, otherwise use the
567  // updated value.
568  return isPre ? IncVal : InVal;
569}
570
571
572//===----------------------------------------------------------------------===//
573//                         LValue Expression Emission
574//===----------------------------------------------------------------------===//
575
576RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
577  if (Ty->isVoidType())
578    return RValue::get(0);
579
580  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
581    const llvm::Type *EltTy = ConvertType(CTy->getElementType());
582    llvm::Value *U = llvm::UndefValue::get(EltTy);
583    return RValue::getComplex(std::make_pair(U, U));
584  }
585
586  // If this is a use of an undefined aggregate type, the aggregate must have an
587  // identifiable address.  Just because the contents of the value are undefined
588  // doesn't mean that the address can't be taken and compared.
589  if (hasAggregateLLVMType(Ty)) {
590    llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
591    return RValue::getAggregate(DestPtr);
592  }
593
594  return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
595}
596
597RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
598                                              const char *Name) {
599  ErrorUnsupported(E, Name);
600  return GetUndefRValue(E->getType());
601}
602
603LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
604                                              const char *Name) {
605  ErrorUnsupported(E, Name);
606  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
607  return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
608}
609
610LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
611  LValue LV = EmitLValue(E);
612  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
613    EmitCheck(LV.getAddress(),
614              getContext().getTypeSizeInChars(E->getType()).getQuantity());
615  return LV;
616}
617
618/// EmitLValue - Emit code to compute a designator that specifies the location
619/// of the expression.
620///
621/// This can return one of two things: a simple address or a bitfield reference.
622/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
623/// an LLVM pointer type.
624///
625/// If this returns a bitfield reference, nothing about the pointee type of the
626/// LLVM value is known: For example, it may not be a pointer to an integer.
627///
628/// If this returns a normal address, and if the lvalue's C type is fixed size,
629/// this method guarantees that the returned pointer type will point to an LLVM
630/// type of the same size of the lvalue's type.  If the lvalue has a variable
631/// length type, this is not possible.
632///
633LValue CodeGenFunction::EmitLValue(const Expr *E) {
634  switch (E->getStmtClass()) {
635  default: return EmitUnsupportedLValue(E, "l-value expression");
636
637  case Expr::ObjCSelectorExprClass:
638  return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
639  case Expr::ObjCIsaExprClass:
640    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
641  case Expr::BinaryOperatorClass:
642    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
643  case Expr::CompoundAssignOperatorClass:
644    if (!E->getType()->isAnyComplexType())
645      return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
646    return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
647  case Expr::CallExprClass:
648  case Expr::CXXMemberCallExprClass:
649  case Expr::CXXOperatorCallExprClass:
650    return EmitCallExprLValue(cast<CallExpr>(E));
651  case Expr::VAArgExprClass:
652    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
653  case Expr::DeclRefExprClass:
654    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
655  case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
656  case Expr::GenericSelectionExprClass:
657    return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
658  case Expr::PredefinedExprClass:
659    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
660  case Expr::StringLiteralClass:
661    return EmitStringLiteralLValue(cast<StringLiteral>(E));
662  case Expr::ObjCEncodeExprClass:
663    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
664
665  case Expr::BlockDeclRefExprClass:
666    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
667
668  case Expr::CXXTemporaryObjectExprClass:
669  case Expr::CXXConstructExprClass:
670    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
671  case Expr::CXXBindTemporaryExprClass:
672    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
673  case Expr::ExprWithCleanupsClass:
674    return EmitExprWithCleanupsLValue(cast<ExprWithCleanups>(E));
675  case Expr::CXXScalarValueInitExprClass:
676    return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
677  case Expr::CXXDefaultArgExprClass:
678    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
679  case Expr::CXXTypeidExprClass:
680    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
681
682  case Expr::ObjCMessageExprClass:
683    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
684  case Expr::ObjCIvarRefExprClass:
685    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
686  case Expr::ObjCPropertyRefExprClass:
687    return EmitObjCPropertyRefLValue(cast<ObjCPropertyRefExpr>(E));
688  case Expr::StmtExprClass:
689    return EmitStmtExprLValue(cast<StmtExpr>(E));
690  case Expr::UnaryOperatorClass:
691    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
692  case Expr::ArraySubscriptExprClass:
693    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
694  case Expr::ExtVectorElementExprClass:
695    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
696  case Expr::MemberExprClass:
697    return EmitMemberExpr(cast<MemberExpr>(E));
698  case Expr::CompoundLiteralExprClass:
699    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
700  case Expr::ConditionalOperatorClass:
701    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
702  case Expr::BinaryConditionalOperatorClass:
703    return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
704  case Expr::ChooseExprClass:
705    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
706  case Expr::OpaqueValueExprClass:
707    return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
708  case Expr::SubstNonTypeTemplateParmExprClass:
709    return EmitLValue(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
710  case Expr::ImplicitCastExprClass:
711  case Expr::CStyleCastExprClass:
712  case Expr::CXXFunctionalCastExprClass:
713  case Expr::CXXStaticCastExprClass:
714  case Expr::CXXDynamicCastExprClass:
715  case Expr::CXXReinterpretCastExprClass:
716  case Expr::CXXConstCastExprClass:
717  case Expr::ObjCBridgedCastExprClass:
718    return EmitCastLValue(cast<CastExpr>(E));
719
720  case Expr::MaterializeTemporaryExprClass:
721    return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
722  }
723}
724
725llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue) {
726  return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
727                          lvalue.getAlignment(), lvalue.getType(),
728                          lvalue.getTBAAInfo());
729}
730
731llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
732                                              unsigned Alignment, QualType Ty,
733                                              llvm::MDNode *TBAAInfo) {
734  llvm::LoadInst *Load = Builder.CreateLoad(Addr, "tmp");
735  if (Volatile)
736    Load->setVolatile(true);
737  if (Alignment)
738    Load->setAlignment(Alignment);
739  if (TBAAInfo)
740    CGM.DecorateInstruction(Load, TBAAInfo);
741
742  return EmitFromMemory(Load, Ty);
743}
744
745static bool isBooleanUnderlyingType(QualType Ty) {
746  if (const EnumType *ET = dyn_cast<EnumType>(Ty))
747    return ET->getDecl()->getIntegerType()->isBooleanType();
748  return false;
749}
750
751llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
752  // Bool has a different representation in memory than in registers.
753  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
754    // This should really always be an i1, but sometimes it's already
755    // an i8, and it's awkward to track those cases down.
756    if (Value->getType()->isIntegerTy(1))
757      return Builder.CreateZExt(Value, Builder.getInt8Ty(), "frombool");
758    assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
759  }
760
761  return Value;
762}
763
764llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
765  // Bool has a different representation in memory than in registers.
766  if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
767    assert(Value->getType()->isIntegerTy(8) && "memory rep of bool not i8");
768    return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
769  }
770
771  return Value;
772}
773
774void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
775                                        bool Volatile, unsigned Alignment,
776                                        QualType Ty,
777                                        llvm::MDNode *TBAAInfo) {
778  Value = EmitToMemory(Value, Ty);
779
780  llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
781  if (Alignment)
782    Store->setAlignment(Alignment);
783  if (TBAAInfo)
784    CGM.DecorateInstruction(Store, TBAAInfo);
785}
786
787void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue) {
788  EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
789                    lvalue.getAlignment(), lvalue.getType(),
790                    lvalue.getTBAAInfo());
791}
792
793/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
794/// method emits the address of the lvalue, then loads the result as an rvalue,
795/// returning the rvalue.
796RValue CodeGenFunction::EmitLoadOfLValue(LValue LV) {
797  if (LV.isObjCWeak()) {
798    // load of a __weak object.
799    llvm::Value *AddrWeakObj = LV.getAddress();
800    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
801                                                             AddrWeakObj));
802  }
803  if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak)
804    return RValue::get(EmitARCLoadWeak(LV.getAddress()));
805
806  if (LV.isSimple()) {
807    assert(!LV.getType()->isFunctionType());
808
809    // Everything needs a load.
810    return RValue::get(EmitLoadOfScalar(LV));
811  }
812
813  if (LV.isVectorElt()) {
814    llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
815                                          LV.isVolatileQualified(), "tmp");
816    return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
817                                                    "vecext"));
818  }
819
820  // If this is a reference to a subset of the elements of a vector, either
821  // shuffle the input or extract/insert them as appropriate.
822  if (LV.isExtVectorElt())
823    return EmitLoadOfExtVectorElementLValue(LV);
824
825  if (LV.isBitField())
826    return EmitLoadOfBitfieldLValue(LV);
827
828  assert(LV.isPropertyRef() && "Unknown LValue type!");
829  return EmitLoadOfPropertyRefLValue(LV);
830}
831
832RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV) {
833  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
834
835  // Get the output type.
836  const llvm::Type *ResLTy = ConvertType(LV.getType());
837  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
838
839  // Compute the result as an OR of all of the individual component accesses.
840  llvm::Value *Res = 0;
841  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
842    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
843
844    // Get the field pointer.
845    llvm::Value *Ptr = LV.getBitFieldBaseAddr();
846
847    // Only offset by the field index if used, so that incoming values are not
848    // required to be structures.
849    if (AI.FieldIndex)
850      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
851
852    // Offset by the byte offset, if used.
853    if (!AI.FieldByteOffset.isZero()) {
854      Ptr = EmitCastToVoidPtr(Ptr);
855      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
856                                       "bf.field.offs");
857    }
858
859    // Cast to the access type.
860    const llvm::Type *PTy = llvm::Type::getIntNPtrTy(getLLVMContext(),
861                                                     AI.AccessWidth,
862                       CGM.getContext().getTargetAddressSpace(LV.getType()));
863    Ptr = Builder.CreateBitCast(Ptr, PTy);
864
865    // Perform the load.
866    llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
867    if (!AI.AccessAlignment.isZero())
868      Load->setAlignment(AI.AccessAlignment.getQuantity());
869
870    // Shift out unused low bits and mask out unused high bits.
871    llvm::Value *Val = Load;
872    if (AI.FieldBitStart)
873      Val = Builder.CreateLShr(Load, AI.FieldBitStart);
874    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
875                                                            AI.TargetBitWidth),
876                            "bf.clear");
877
878    // Extend or truncate to the target size.
879    if (AI.AccessWidth < ResSizeInBits)
880      Val = Builder.CreateZExt(Val, ResLTy);
881    else if (AI.AccessWidth > ResSizeInBits)
882      Val = Builder.CreateTrunc(Val, ResLTy);
883
884    // Shift into place, and OR into the result.
885    if (AI.TargetBitOffset)
886      Val = Builder.CreateShl(Val, AI.TargetBitOffset);
887    Res = Res ? Builder.CreateOr(Res, Val) : Val;
888  }
889
890  // If the bit-field is signed, perform the sign-extension.
891  //
892  // FIXME: This can easily be folded into the load of the high bits, which
893  // could also eliminate the mask of high bits in some situations.
894  if (Info.isSigned()) {
895    unsigned ExtraBits = ResSizeInBits - Info.getSize();
896    if (ExtraBits)
897      Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
898                               ExtraBits, "bf.val.sext");
899  }
900
901  return RValue::get(Res);
902}
903
904// If this is a reference to a subset of the elements of a vector, create an
905// appropriate shufflevector.
906RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) {
907  llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
908                                        LV.isVolatileQualified(), "tmp");
909
910  const llvm::Constant *Elts = LV.getExtVectorElts();
911
912  // If the result of the expression is a non-vector type, we must be extracting
913  // a single element.  Just codegen as an extractelement.
914  const VectorType *ExprVT = LV.getType()->getAs<VectorType>();
915  if (!ExprVT) {
916    unsigned InIdx = getAccessedFieldNo(0, Elts);
917    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
918    return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
919  }
920
921  // Always use shuffle vector to try to retain the original program structure
922  unsigned NumResultElts = ExprVT->getNumElements();
923
924  llvm::SmallVector<llvm::Constant*, 4> Mask;
925  for (unsigned i = 0; i != NumResultElts; ++i) {
926    unsigned InIdx = getAccessedFieldNo(i, Elts);
927    Mask.push_back(llvm::ConstantInt::get(Int32Ty, InIdx));
928  }
929
930  llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
931  Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()),
932                                    MaskV, "tmp");
933  return RValue::get(Vec);
934}
935
936
937
938/// EmitStoreThroughLValue - Store the specified rvalue into the specified
939/// lvalue, where both are guaranteed to the have the same type, and that type
940/// is 'Ty'.
941void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst) {
942  if (!Dst.isSimple()) {
943    if (Dst.isVectorElt()) {
944      // Read/modify/write the vector, inserting the new element.
945      llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
946                                            Dst.isVolatileQualified(), "tmp");
947      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
948                                        Dst.getVectorIdx(), "vecins");
949      Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
950      return;
951    }
952
953    // If this is an update of extended vector elements, insert them as
954    // appropriate.
955    if (Dst.isExtVectorElt())
956      return EmitStoreThroughExtVectorComponentLValue(Src, Dst);
957
958    if (Dst.isBitField())
959      return EmitStoreThroughBitfieldLValue(Src, Dst);
960
961    assert(Dst.isPropertyRef() && "Unknown LValue type");
962    return EmitStoreThroughPropertyRefLValue(Src, Dst);
963  }
964
965  // There's special magic for assigning into an ARC-qualified l-value.
966  if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) {
967    switch (Lifetime) {
968    case Qualifiers::OCL_None:
969      llvm_unreachable("present but none");
970
971    case Qualifiers::OCL_ExplicitNone:
972      // nothing special
973      break;
974
975    case Qualifiers::OCL_Strong:
976      EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
977      return;
978
979    case Qualifiers::OCL_Weak:
980      EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
981      return;
982
983    case Qualifiers::OCL_Autoreleasing:
984      Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(),
985                                                     Src.getScalarVal()));
986      // fall into the normal path
987      break;
988    }
989  }
990
991  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
992    // load of a __weak object.
993    llvm::Value *LvalueDst = Dst.getAddress();
994    llvm::Value *src = Src.getScalarVal();
995     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
996    return;
997  }
998
999  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
1000    // load of a __strong object.
1001    llvm::Value *LvalueDst = Dst.getAddress();
1002    llvm::Value *src = Src.getScalarVal();
1003    if (Dst.isObjCIvar()) {
1004      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
1005      const llvm::Type *ResultType = ConvertType(getContext().LongTy);
1006      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
1007      llvm::Value *dst = RHS;
1008      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
1009      llvm::Value *LHS =
1010        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
1011      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
1012      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
1013                                              BytesBetween);
1014    } else if (Dst.isGlobalObjCRef()) {
1015      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
1016                                                Dst.isThreadLocalRef());
1017    }
1018    else
1019      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
1020    return;
1021  }
1022
1023  assert(Src.isScalar() && "Can't emit an agg store with this method");
1024  EmitStoreOfScalar(Src.getScalarVal(), Dst);
1025}
1026
1027void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
1028                                                     llvm::Value **Result) {
1029  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
1030
1031  // Get the output type.
1032  const llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
1033  unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
1034
1035  // Get the source value, truncated to the width of the bit-field.
1036  llvm::Value *SrcVal = Src.getScalarVal();
1037
1038  if (Dst.getType()->isBooleanType())
1039    SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
1040
1041  SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
1042                                                                Info.getSize()),
1043                             "bf.value");
1044
1045  // Return the new value of the bit-field, if requested.
1046  if (Result) {
1047    // Cast back to the proper type for result.
1048    const llvm::Type *SrcTy = Src.getScalarVal()->getType();
1049    llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
1050                                                   "bf.reload.val");
1051
1052    // Sign extend if necessary.
1053    if (Info.isSigned()) {
1054      unsigned ExtraBits = ResSizeInBits - Info.getSize();
1055      if (ExtraBits)
1056        ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
1057                                       ExtraBits, "bf.reload.sext");
1058    }
1059
1060    *Result = ReloadVal;
1061  }
1062
1063  // Iterate over the components, writing each piece to memory.
1064  for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
1065    const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
1066
1067    // Get the field pointer.
1068    llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
1069    unsigned addressSpace =
1070      cast<llvm::PointerType>(Ptr->getType())->getAddressSpace();
1071
1072    // Only offset by the field index if used, so that incoming values are not
1073    // required to be structures.
1074    if (AI.FieldIndex)
1075      Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
1076
1077    // Offset by the byte offset, if used.
1078    if (!AI.FieldByteOffset.isZero()) {
1079      Ptr = EmitCastToVoidPtr(Ptr);
1080      Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
1081                                       "bf.field.offs");
1082    }
1083
1084    // Cast to the access type.
1085    const llvm::Type *AccessLTy =
1086      llvm::Type::getIntNTy(getLLVMContext(), AI.AccessWidth);
1087
1088    const llvm::Type *PTy = AccessLTy->getPointerTo(addressSpace);
1089    Ptr = Builder.CreateBitCast(Ptr, PTy);
1090
1091    // Extract the piece of the bit-field value to write in this access, limited
1092    // to the values that are part of this access.
1093    llvm::Value *Val = SrcVal;
1094    if (AI.TargetBitOffset)
1095      Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
1096    Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
1097                                                            AI.TargetBitWidth));
1098
1099    // Extend or truncate to the access size.
1100    if (ResSizeInBits < AI.AccessWidth)
1101      Val = Builder.CreateZExt(Val, AccessLTy);
1102    else if (ResSizeInBits > AI.AccessWidth)
1103      Val = Builder.CreateTrunc(Val, AccessLTy);
1104
1105    // Shift into the position in memory.
1106    if (AI.FieldBitStart)
1107      Val = Builder.CreateShl(Val, AI.FieldBitStart);
1108
1109    // If necessary, load and OR in bits that are outside of the bit-field.
1110    if (AI.TargetBitWidth != AI.AccessWidth) {
1111      llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
1112      if (!AI.AccessAlignment.isZero())
1113        Load->setAlignment(AI.AccessAlignment.getQuantity());
1114
1115      // Compute the mask for zeroing the bits that are part of the bit-field.
1116      llvm::APInt InvMask =
1117        ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
1118                                 AI.FieldBitStart + AI.TargetBitWidth);
1119
1120      // Apply the mask and OR in to the value to write.
1121      Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
1122    }
1123
1124    // Write the value.
1125    llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
1126                                                 Dst.isVolatileQualified());
1127    if (!AI.AccessAlignment.isZero())
1128      Store->setAlignment(AI.AccessAlignment.getQuantity());
1129  }
1130}
1131
1132void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
1133                                                               LValue Dst) {
1134  // This access turns into a read/modify/write of the vector.  Load the input
1135  // value now.
1136  llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
1137                                        Dst.isVolatileQualified(), "tmp");
1138  const llvm::Constant *Elts = Dst.getExtVectorElts();
1139
1140  llvm::Value *SrcVal = Src.getScalarVal();
1141
1142  if (const VectorType *VTy = Dst.getType()->getAs<VectorType>()) {
1143    unsigned NumSrcElts = VTy->getNumElements();
1144    unsigned NumDstElts =
1145       cast<llvm::VectorType>(Vec->getType())->getNumElements();
1146    if (NumDstElts == NumSrcElts) {
1147      // Use shuffle vector is the src and destination are the same number of
1148      // elements and restore the vector mask since it is on the side it will be
1149      // stored.
1150      llvm::SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
1151      for (unsigned i = 0; i != NumSrcElts; ++i) {
1152        unsigned InIdx = getAccessedFieldNo(i, Elts);
1153        Mask[InIdx] = llvm::ConstantInt::get(Int32Ty, i);
1154      }
1155
1156      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1157      Vec = Builder.CreateShuffleVector(SrcVal,
1158                                        llvm::UndefValue::get(Vec->getType()),
1159                                        MaskV, "tmp");
1160    } else if (NumDstElts > NumSrcElts) {
1161      // Extended the source vector to the same length and then shuffle it
1162      // into the destination.
1163      // FIXME: since we're shuffling with undef, can we just use the indices
1164      //        into that?  This could be simpler.
1165      llvm::SmallVector<llvm::Constant*, 4> ExtMask;
1166      unsigned i;
1167      for (i = 0; i != NumSrcElts; ++i)
1168        ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1169      for (; i != NumDstElts; ++i)
1170        ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
1171      llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
1172      llvm::Value *ExtSrcVal =
1173        Builder.CreateShuffleVector(SrcVal,
1174                                    llvm::UndefValue::get(SrcVal->getType()),
1175                                    ExtMaskV, "tmp");
1176      // build identity
1177      llvm::SmallVector<llvm::Constant*, 4> Mask;
1178      for (unsigned i = 0; i != NumDstElts; ++i)
1179        Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1180
1181      // modify when what gets shuffled in
1182      for (unsigned i = 0; i != NumSrcElts; ++i) {
1183        unsigned Idx = getAccessedFieldNo(i, Elts);
1184        Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
1185      }
1186      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1187      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV, "tmp");
1188    } else {
1189      // We should never shorten the vector
1190      assert(0 && "unexpected shorten vector length");
1191    }
1192  } else {
1193    // If the Src is a scalar (not a vector) it must be updating one element.
1194    unsigned InIdx = getAccessedFieldNo(0, Elts);
1195    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1196    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
1197  }
1198
1199  Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1200}
1201
1202// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1203// generating write-barries API. It is currently a global, ivar,
1204// or neither.
1205static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1206                                 LValue &LV) {
1207  if (Ctx.getLangOptions().getGCMode() == LangOptions::NonGC)
1208    return;
1209
1210  if (isa<ObjCIvarRefExpr>(E)) {
1211    LV.setObjCIvar(true);
1212    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1213    LV.setBaseIvarExp(Exp->getBase());
1214    LV.setObjCArray(E->getType()->isArrayType());
1215    return;
1216  }
1217
1218  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1219    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1220      if (VD->hasGlobalStorage()) {
1221        LV.setGlobalObjCRef(true);
1222        LV.setThreadLocalRef(VD->isThreadSpecified());
1223      }
1224    }
1225    LV.setObjCArray(E->getType()->isArrayType());
1226    return;
1227  }
1228
1229  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1230    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1231    return;
1232  }
1233
1234  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1235    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1236    if (LV.isObjCIvar()) {
1237      // If cast is to a structure pointer, follow gcc's behavior and make it
1238      // a non-ivar write-barrier.
1239      QualType ExpTy = E->getType();
1240      if (ExpTy->isPointerType())
1241        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1242      if (ExpTy->isRecordType())
1243        LV.setObjCIvar(false);
1244    }
1245    return;
1246  }
1247
1248  if (const GenericSelectionExpr *Exp = dyn_cast<GenericSelectionExpr>(E)) {
1249    setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
1250    return;
1251  }
1252
1253  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1254    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1255    return;
1256  }
1257
1258  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1259    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1260    return;
1261  }
1262
1263  if (const ObjCBridgedCastExpr *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
1264    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV);
1265    return;
1266  }
1267
1268  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1269    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1270    if (LV.isObjCIvar() && !LV.isObjCArray())
1271      // Using array syntax to assigning to what an ivar points to is not
1272      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1273      LV.setObjCIvar(false);
1274    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1275      // Using array syntax to assigning to what global points to is not
1276      // same as assigning to the global itself. {id *G;} G[i] = 0;
1277      LV.setGlobalObjCRef(false);
1278    return;
1279  }
1280
1281  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1282    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1283    // We don't know if member is an 'ivar', but this flag is looked at
1284    // only in the context of LV.isObjCIvar().
1285    LV.setObjCArray(E->getType()->isArrayType());
1286    return;
1287  }
1288}
1289
1290static llvm::Value *
1291EmitBitCastOfLValueToProperType(CodeGenFunction &CGF,
1292                                llvm::Value *V, llvm::Type *IRType,
1293                                llvm::StringRef Name = llvm::StringRef()) {
1294  unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
1295  return CGF.Builder.CreateBitCast(V, IRType->getPointerTo(AS), Name);
1296}
1297
1298static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1299                                      const Expr *E, const VarDecl *VD) {
1300  assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1301         "Var decl must have external storage or be a file var decl!");
1302
1303  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1304  if (VD->getType()->isReferenceType())
1305    V = CGF.Builder.CreateLoad(V, "tmp");
1306
1307  V = EmitBitCastOfLValueToProperType(CGF, V,
1308                                CGF.getTypes().ConvertTypeForMem(E->getType()));
1309
1310  unsigned Alignment = CGF.getContext().getDeclAlign(VD).getQuantity();
1311  LValue LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1312  setObjCGCLValueClass(CGF.getContext(), E, LV);
1313  return LV;
1314}
1315
1316static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1317                                     const Expr *E, const FunctionDecl *FD) {
1318  llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1319  if (!FD->hasPrototype()) {
1320    if (const FunctionProtoType *Proto =
1321            FD->getType()->getAs<FunctionProtoType>()) {
1322      // Ugly case: for a K&R-style definition, the type of the definition
1323      // isn't the same as the type of a use.  Correct for this with a
1324      // bitcast.
1325      QualType NoProtoType =
1326          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1327      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1328      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType), "tmp");
1329    }
1330  }
1331  unsigned Alignment = CGF.getContext().getDeclAlign(FD).getQuantity();
1332  return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1333}
1334
1335LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1336  const NamedDecl *ND = E->getDecl();
1337  unsigned Alignment = getContext().getDeclAlign(ND).getQuantity();
1338
1339  if (ND->hasAttr<WeakRefAttr>()) {
1340    const ValueDecl *VD = cast<ValueDecl>(ND);
1341    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1342    return MakeAddrLValue(Aliasee, E->getType(), Alignment);
1343  }
1344
1345  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1346
1347    // Check if this is a global variable.
1348    if (VD->hasExternalStorage() || VD->isFileVarDecl())
1349      return EmitGlobalVarDeclLValue(*this, E, VD);
1350
1351    bool NonGCable = VD->hasLocalStorage() &&
1352                     !VD->getType()->isReferenceType() &&
1353                     !VD->hasAttr<BlocksAttr>();
1354
1355    llvm::Value *V = LocalDeclMap[VD];
1356    if (!V && VD->isStaticLocal())
1357      V = CGM.getStaticLocalDeclAddress(VD);
1358    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1359
1360    if (VD->hasAttr<BlocksAttr>())
1361      V = BuildBlockByrefAddress(V, VD);
1362
1363    if (VD->getType()->isReferenceType())
1364      V = Builder.CreateLoad(V, "tmp");
1365
1366    V = EmitBitCastOfLValueToProperType(*this, V,
1367                                    getTypes().ConvertTypeForMem(E->getType()));
1368
1369    LValue LV = MakeAddrLValue(V, E->getType(), Alignment);
1370    if (NonGCable) {
1371      LV.getQuals().removeObjCGCAttr();
1372      LV.setNonGC(true);
1373    }
1374    setObjCGCLValueClass(getContext(), E, LV);
1375    return LV;
1376  }
1377
1378  if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
1379    return EmitFunctionDeclLValue(*this, E, fn);
1380
1381  assert(false && "Unhandled DeclRefExpr");
1382
1383  // an invalid LValue, but the assert will
1384  // ensure that this point is never reached.
1385  return LValue();
1386}
1387
1388LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1389  unsigned Alignment =
1390    getContext().getDeclAlign(E->getDecl()).getQuantity();
1391  return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
1392}
1393
1394LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1395  // __extension__ doesn't affect lvalue-ness.
1396  if (E->getOpcode() == UO_Extension)
1397    return EmitLValue(E->getSubExpr());
1398
1399  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1400  switch (E->getOpcode()) {
1401  default: assert(0 && "Unknown unary operator lvalue!");
1402  case UO_Deref: {
1403    QualType T = E->getSubExpr()->getType()->getPointeeType();
1404    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1405
1406    LValue LV = MakeAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1407    LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1408
1409    // We should not generate __weak write barrier on indirect reference
1410    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1411    // But, we continue to generate __strong write barrier on indirect write
1412    // into a pointer to object.
1413    if (getContext().getLangOptions().ObjC1 &&
1414        getContext().getLangOptions().getGCMode() != LangOptions::NonGC &&
1415        LV.isObjCWeak())
1416      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1417    return LV;
1418  }
1419  case UO_Real:
1420  case UO_Imag: {
1421    LValue LV = EmitLValue(E->getSubExpr());
1422    assert(LV.isSimple() && "real/imag on non-ordinary l-value");
1423    llvm::Value *Addr = LV.getAddress();
1424
1425    // real and imag are valid on scalars.  This is a faster way of
1426    // testing that.
1427    if (!cast<llvm::PointerType>(Addr->getType())
1428           ->getElementType()->isStructTy()) {
1429      assert(E->getSubExpr()->getType()->isArithmeticType());
1430      return LV;
1431    }
1432
1433    assert(E->getSubExpr()->getType()->isAnyComplexType());
1434
1435    unsigned Idx = E->getOpcode() == UO_Imag;
1436    return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1437                                                  Idx, "idx"),
1438                          ExprTy);
1439  }
1440  case UO_PreInc:
1441  case UO_PreDec: {
1442    LValue LV = EmitLValue(E->getSubExpr());
1443    bool isInc = E->getOpcode() == UO_PreInc;
1444
1445    if (E->getType()->isAnyComplexType())
1446      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1447    else
1448      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1449    return LV;
1450  }
1451  }
1452}
1453
1454LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1455  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1456                        E->getType());
1457}
1458
1459LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1460  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1461                        E->getType());
1462}
1463
1464
1465LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1466  switch (E->getIdentType()) {
1467  default:
1468    return EmitUnsupportedLValue(E, "predefined expression");
1469
1470  case PredefinedExpr::Func:
1471  case PredefinedExpr::Function:
1472  case PredefinedExpr::PrettyFunction: {
1473    unsigned Type = E->getIdentType();
1474    std::string GlobalVarName;
1475
1476    switch (Type) {
1477    default: assert(0 && "Invalid type");
1478    case PredefinedExpr::Func:
1479      GlobalVarName = "__func__.";
1480      break;
1481    case PredefinedExpr::Function:
1482      GlobalVarName = "__FUNCTION__.";
1483      break;
1484    case PredefinedExpr::PrettyFunction:
1485      GlobalVarName = "__PRETTY_FUNCTION__.";
1486      break;
1487    }
1488
1489    llvm::StringRef FnName = CurFn->getName();
1490    if (FnName.startswith("\01"))
1491      FnName = FnName.substr(1);
1492    GlobalVarName += FnName;
1493
1494    const Decl *CurDecl = CurCodeDecl;
1495    if (CurDecl == 0)
1496      CurDecl = getContext().getTranslationUnitDecl();
1497
1498    std::string FunctionName =
1499        (isa<BlockDecl>(CurDecl)
1500         ? FnName.str()
1501         : PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl));
1502
1503    llvm::Constant *C =
1504      CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1505    return MakeAddrLValue(C, E->getType());
1506  }
1507  }
1508}
1509
1510llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1511  const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1512
1513  // If we are not optimzing, don't collapse all calls to trap in the function
1514  // to the same call, that way, in the debugger they can see which operation
1515  // did in fact fail.  If we are optimizing, we collapse all calls to trap down
1516  // to just one per function to save on codesize.
1517  if (GCO.OptimizationLevel && TrapBB)
1518    return TrapBB;
1519
1520  llvm::BasicBlock *Cont = 0;
1521  if (HaveInsertPoint()) {
1522    Cont = createBasicBlock("cont");
1523    EmitBranch(Cont);
1524  }
1525  TrapBB = createBasicBlock("trap");
1526  EmitBlock(TrapBB);
1527
1528  llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap);
1529  llvm::CallInst *TrapCall = Builder.CreateCall(F);
1530  TrapCall->setDoesNotReturn();
1531  TrapCall->setDoesNotThrow();
1532  Builder.CreateUnreachable();
1533
1534  if (Cont)
1535    EmitBlock(Cont);
1536  return TrapBB;
1537}
1538
1539/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
1540/// array to pointer, return the array subexpression.
1541static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
1542  // If this isn't just an array->pointer decay, bail out.
1543  const CastExpr *CE = dyn_cast<CastExpr>(E);
1544  if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
1545    return 0;
1546
1547  // If this is a decay from variable width array, bail out.
1548  const Expr *SubExpr = CE->getSubExpr();
1549  if (SubExpr->getType()->isVariableArrayType())
1550    return 0;
1551
1552  return SubExpr;
1553}
1554
1555LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1556  // The index must always be an integer, which is not an aggregate.  Emit it.
1557  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1558  QualType IdxTy  = E->getIdx()->getType();
1559  bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
1560
1561  // If the base is a vector type, then we are forming a vector element lvalue
1562  // with this subscript.
1563  if (E->getBase()->getType()->isVectorType()) {
1564    // Emit the vector as an lvalue to get its address.
1565    LValue LHS = EmitLValue(E->getBase());
1566    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1567    Idx = Builder.CreateIntCast(Idx, Int32Ty, IdxSigned, "vidx");
1568    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1569                                 E->getBase()->getType());
1570  }
1571
1572  // Extend or truncate the index type to 32 or 64-bits.
1573  if (Idx->getType() != IntPtrTy)
1574    Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
1575
1576  // FIXME: As llvm implements the object size checking, this can come out.
1577  if (CatchUndefined) {
1578    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())){
1579      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1580        if (ICE->getCastKind() == CK_ArrayToPointerDecay) {
1581          if (const ConstantArrayType *CAT
1582              = getContext().getAsConstantArrayType(DRE->getType())) {
1583            llvm::APInt Size = CAT->getSize();
1584            llvm::BasicBlock *Cont = createBasicBlock("cont");
1585            Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1586                                  llvm::ConstantInt::get(Idx->getType(), Size)),
1587                                 Cont, getTrapBB());
1588            EmitBlock(Cont);
1589          }
1590        }
1591      }
1592    }
1593  }
1594
1595  // We know that the pointer points to a type of the correct size, unless the
1596  // size is a VLA or Objective-C interface.
1597  llvm::Value *Address = 0;
1598  unsigned ArrayAlignment = 0;
1599  if (const VariableArrayType *vla =
1600        getContext().getAsVariableArrayType(E->getType())) {
1601    // The base must be a pointer, which is not an aggregate.  Emit
1602    // it.  It needs to be emitted first in case it's what captures
1603    // the VLA bounds.
1604    Address = EmitScalarExpr(E->getBase());
1605
1606    // The element count here is the total number of non-VLA elements.
1607    llvm::Value *numElements = getVLASize(vla).first;
1608
1609    // Effectively, the multiply by the VLA size is part of the GEP.
1610    // GEP indexes are signed, and scaling an index isn't permitted to
1611    // signed-overflow, so we use the same semantics for our explicit
1612    // multiply.  We suppress this if overflow is not undefined behavior.
1613    if (getLangOptions().isSignedOverflowDefined()) {
1614      Idx = Builder.CreateMul(Idx, numElements);
1615      Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1616    } else {
1617      Idx = Builder.CreateNSWMul(Idx, numElements);
1618      Address = Builder.CreateInBoundsGEP(Address, Idx, "arrayidx");
1619    }
1620  } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
1621    // Indexing over an interface, as in "NSString *P; P[4];"
1622    llvm::Value *InterfaceSize =
1623      llvm::ConstantInt::get(Idx->getType(),
1624          getContext().getTypeSizeInChars(OIT).getQuantity());
1625
1626    Idx = Builder.CreateMul(Idx, InterfaceSize);
1627
1628    // The base must be a pointer, which is not an aggregate.  Emit it.
1629    llvm::Value *Base = EmitScalarExpr(E->getBase());
1630    Address = EmitCastToVoidPtr(Base);
1631    Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1632    Address = Builder.CreateBitCast(Address, Base->getType());
1633  } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
1634    // If this is A[i] where A is an array, the frontend will have decayed the
1635    // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
1636    // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
1637    // "gep x, i" here.  Emit one "gep A, 0, i".
1638    assert(Array->getType()->isArrayType() &&
1639           "Array to pointer decay must have array source type!");
1640    LValue ArrayLV = EmitLValue(Array);
1641    llvm::Value *ArrayPtr = ArrayLV.getAddress();
1642    llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
1643    llvm::Value *Args[] = { Zero, Idx };
1644
1645    // Propagate the alignment from the array itself to the result.
1646    ArrayAlignment = ArrayLV.getAlignment();
1647
1648    if (getContext().getLangOptions().isSignedOverflowDefined())
1649      Address = Builder.CreateGEP(ArrayPtr, Args, Args+2, "arrayidx");
1650    else
1651      Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, Args+2, "arrayidx");
1652  } else {
1653    // The base must be a pointer, which is not an aggregate.  Emit it.
1654    llvm::Value *Base = EmitScalarExpr(E->getBase());
1655    if (getContext().getLangOptions().isSignedOverflowDefined())
1656      Address = Builder.CreateGEP(Base, Idx, "arrayidx");
1657    else
1658      Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1659  }
1660
1661  QualType T = E->getBase()->getType()->getPointeeType();
1662  assert(!T.isNull() &&
1663         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1664
1665  // Limit the alignment to that of the result type.
1666  if (ArrayAlignment) {
1667    unsigned Align = getContext().getTypeAlignInChars(T).getQuantity();
1668    ArrayAlignment = std::min(Align, ArrayAlignment);
1669  }
1670
1671  LValue LV = MakeAddrLValue(Address, T, ArrayAlignment);
1672  LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
1673
1674  if (getContext().getLangOptions().ObjC1 &&
1675      getContext().getLangOptions().getGCMode() != LangOptions::NonGC) {
1676    LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1677    setObjCGCLValueClass(getContext(), E, LV);
1678  }
1679  return LV;
1680}
1681
1682static
1683llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1684                                       llvm::SmallVector<unsigned, 4> &Elts) {
1685  llvm::SmallVector<llvm::Constant*, 4> CElts;
1686
1687  const llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1688  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1689    CElts.push_back(llvm::ConstantInt::get(Int32Ty, Elts[i]));
1690
1691  return llvm::ConstantVector::get(CElts);
1692}
1693
1694LValue CodeGenFunction::
1695EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1696  // Emit the base vector as an l-value.
1697  LValue Base;
1698
1699  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1700  if (E->isArrow()) {
1701    // If it is a pointer to a vector, emit the address and form an lvalue with
1702    // it.
1703    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1704    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1705    Base = MakeAddrLValue(Ptr, PT->getPointeeType());
1706    Base.getQuals().removeObjCGCAttr();
1707  } else if (E->getBase()->isGLValue()) {
1708    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1709    // emit the base as an lvalue.
1710    assert(E->getBase()->getType()->isVectorType());
1711    Base = EmitLValue(E->getBase());
1712  } else {
1713    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1714    assert(E->getBase()->getType()->isVectorType() &&
1715           "Result must be a vector");
1716    llvm::Value *Vec = EmitScalarExpr(E->getBase());
1717
1718    // Store the vector to memory (because LValue wants an address).
1719    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1720    Builder.CreateStore(Vec, VecMem);
1721    Base = MakeAddrLValue(VecMem, E->getBase()->getType());
1722  }
1723
1724  QualType type =
1725    E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers());
1726
1727  // Encode the element access list into a vector of unsigned indices.
1728  llvm::SmallVector<unsigned, 4> Indices;
1729  E->getEncodedElementAccess(Indices);
1730
1731  if (Base.isSimple()) {
1732    llvm::Constant *CV = GenerateConstantVector(getLLVMContext(), Indices);
1733    return LValue::MakeExtVectorElt(Base.getAddress(), CV, type);
1734  }
1735  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1736
1737  llvm::Constant *BaseElts = Base.getExtVectorElts();
1738  llvm::SmallVector<llvm::Constant *, 4> CElts;
1739
1740  for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1741    if (isa<llvm::ConstantAggregateZero>(BaseElts))
1742      CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1743    else
1744      CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1745  }
1746  llvm::Constant *CV = llvm::ConstantVector::get(CElts);
1747  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV, type);
1748}
1749
1750LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1751  bool isNonGC = false;
1752  Expr *BaseExpr = E->getBase();
1753  llvm::Value *BaseValue = NULL;
1754  Qualifiers BaseQuals;
1755
1756  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1757  if (E->isArrow()) {
1758    BaseValue = EmitScalarExpr(BaseExpr);
1759    const PointerType *PTy =
1760      BaseExpr->getType()->getAs<PointerType>();
1761    BaseQuals = PTy->getPointeeType().getQualifiers();
1762  } else {
1763    LValue BaseLV = EmitLValue(BaseExpr);
1764    if (BaseLV.isNonGC())
1765      isNonGC = true;
1766    // FIXME: this isn't right for bitfields.
1767    BaseValue = BaseLV.getAddress();
1768    QualType BaseTy = BaseExpr->getType();
1769    BaseQuals = BaseTy.getQualifiers();
1770  }
1771
1772  NamedDecl *ND = E->getMemberDecl();
1773  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1774    LValue LV = EmitLValueForField(BaseValue, Field,
1775                                   BaseQuals.getCVRQualifiers());
1776    LV.setNonGC(isNonGC);
1777    setObjCGCLValueClass(getContext(), E, LV);
1778    return LV;
1779  }
1780
1781  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1782    return EmitGlobalVarDeclLValue(*this, E, VD);
1783
1784  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1785    return EmitFunctionDeclLValue(*this, E, FD);
1786
1787  assert(false && "Unhandled member declaration!");
1788  return LValue();
1789}
1790
1791LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
1792                                              const FieldDecl *Field,
1793                                              unsigned CVRQualifiers) {
1794  const CGRecordLayout &RL =
1795    CGM.getTypes().getCGRecordLayout(Field->getParent());
1796  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1797  return LValue::MakeBitfield(BaseValue, Info,
1798                          Field->getType().withCVRQualifiers(CVRQualifiers));
1799}
1800
1801/// EmitLValueForAnonRecordField - Given that the field is a member of
1802/// an anonymous struct or union buried inside a record, and given
1803/// that the base value is a pointer to the enclosing record, derive
1804/// an lvalue for the ultimate field.
1805LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
1806                                             const IndirectFieldDecl *Field,
1807                                                     unsigned CVRQualifiers) {
1808  IndirectFieldDecl::chain_iterator I = Field->chain_begin(),
1809    IEnd = Field->chain_end();
1810  while (true) {
1811    LValue LV = EmitLValueForField(BaseValue, cast<FieldDecl>(*I),
1812                                   CVRQualifiers);
1813    if (++I == IEnd) return LV;
1814
1815    assert(LV.isSimple());
1816    BaseValue = LV.getAddress();
1817    CVRQualifiers |= LV.getVRQualifiers();
1818  }
1819}
1820
1821LValue CodeGenFunction::EmitLValueForField(llvm::Value *baseAddr,
1822                                           const FieldDecl *field,
1823                                           unsigned cvr) {
1824  if (field->isBitField())
1825    return EmitLValueForBitfield(baseAddr, field, cvr);
1826
1827  const RecordDecl *rec = field->getParent();
1828  QualType type = field->getType();
1829
1830  bool mayAlias = rec->hasAttr<MayAliasAttr>();
1831
1832  llvm::Value *addr = baseAddr;
1833  if (rec->isUnion()) {
1834    // For unions, there is no pointer adjustment.
1835    assert(!type->isReferenceType() && "union has reference member");
1836  } else {
1837    // For structs, we GEP to the field that the record layout suggests.
1838    unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
1839    addr = Builder.CreateStructGEP(addr, idx, field->getName());
1840
1841    // If this is a reference field, load the reference right now.
1842    if (const ReferenceType *refType = type->getAs<ReferenceType>()) {
1843      llvm::LoadInst *load = Builder.CreateLoad(addr, "ref");
1844      if (cvr & Qualifiers::Volatile) load->setVolatile(true);
1845
1846      if (CGM.shouldUseTBAA()) {
1847        llvm::MDNode *tbaa;
1848        if (mayAlias)
1849          tbaa = CGM.getTBAAInfo(getContext().CharTy);
1850        else
1851          tbaa = CGM.getTBAAInfo(type);
1852        CGM.DecorateInstruction(load, tbaa);
1853      }
1854
1855      addr = load;
1856      mayAlias = false;
1857      type = refType->getPointeeType();
1858      cvr = 0; // qualifiers don't recursively apply to referencee
1859    }
1860  }
1861
1862  // Make sure that the address is pointing to the right type.  This is critical
1863  // for both unions and structs.  A union needs a bitcast, a struct element
1864  // will need a bitcast if the LLVM type laid out doesn't match the desired
1865  // type.
1866  addr = EmitBitCastOfLValueToProperType(*this, addr,
1867                                         CGM.getTypes().ConvertTypeForMem(type),
1868                                         field->getName());
1869
1870  unsigned alignment = getContext().getDeclAlign(field).getQuantity();
1871  LValue LV = MakeAddrLValue(addr, type, alignment);
1872  LV.getQuals().addCVRQualifiers(cvr);
1873
1874  // __weak attribute on a field is ignored.
1875  if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
1876    LV.getQuals().removeObjCGCAttr();
1877
1878  // Fields of may_alias structs act like 'char' for TBAA purposes.
1879  // FIXME: this should get propagated down through anonymous structs
1880  // and unions.
1881  if (mayAlias && LV.getTBAAInfo())
1882    LV.setTBAAInfo(CGM.getTBAAInfo(getContext().CharTy));
1883
1884  return LV;
1885}
1886
1887LValue
1888CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value *BaseValue,
1889                                                  const FieldDecl *Field,
1890                                                  unsigned CVRQualifiers) {
1891  QualType FieldType = Field->getType();
1892
1893  if (!FieldType->isReferenceType())
1894    return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1895
1896  const CGRecordLayout &RL =
1897    CGM.getTypes().getCGRecordLayout(Field->getParent());
1898  unsigned idx = RL.getLLVMFieldNo(Field);
1899  llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
1900  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1901
1902
1903  // Make sure that the address is pointing to the right type.  This is critical
1904  // for both unions and structs.  A union needs a bitcast, a struct element
1905  // will need a bitcast if the LLVM type laid out doesn't match the desired
1906  // type.
1907  const llvm::Type *llvmType = ConvertTypeForMem(FieldType);
1908  unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
1909  V = Builder.CreateBitCast(V, llvmType->getPointerTo(AS));
1910
1911  unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1912  return MakeAddrLValue(V, FieldType, Alignment);
1913}
1914
1915LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
1916  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1917  const Expr *InitExpr = E->getInitializer();
1918  LValue Result = MakeAddrLValue(DeclPtr, E->getType());
1919
1920  EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
1921                   /*Init*/ true);
1922
1923  return Result;
1924}
1925
1926LValue CodeGenFunction::
1927EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
1928  if (!expr->isGLValue()) {
1929    // ?: here should be an aggregate.
1930    assert((hasAggregateLLVMType(expr->getType()) &&
1931            !expr->getType()->isAnyComplexType()) &&
1932           "Unexpected conditional operator!");
1933    return EmitAggExprToLValue(expr);
1934  }
1935
1936  const Expr *condExpr = expr->getCond();
1937  bool CondExprBool;
1938  if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
1939    const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr();
1940    if (!CondExprBool) std::swap(live, dead);
1941
1942    if (!ContainsLabel(dead))
1943      return EmitLValue(live);
1944  }
1945
1946  OpaqueValueMapping binding(*this, expr);
1947
1948  llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
1949  llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
1950  llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
1951
1952  ConditionalEvaluation eval(*this);
1953  EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock);
1954
1955  // Any temporaries created here are conditional.
1956  EmitBlock(lhsBlock);
1957  eval.begin(*this);
1958  LValue lhs = EmitLValue(expr->getTrueExpr());
1959  eval.end(*this);
1960
1961  if (!lhs.isSimple())
1962    return EmitUnsupportedLValue(expr, "conditional operator");
1963
1964  lhsBlock = Builder.GetInsertBlock();
1965  Builder.CreateBr(contBlock);
1966
1967  // Any temporaries created here are conditional.
1968  EmitBlock(rhsBlock);
1969  eval.begin(*this);
1970  LValue rhs = EmitLValue(expr->getFalseExpr());
1971  eval.end(*this);
1972  if (!rhs.isSimple())
1973    return EmitUnsupportedLValue(expr, "conditional operator");
1974  rhsBlock = Builder.GetInsertBlock();
1975
1976  EmitBlock(contBlock);
1977
1978  llvm::PHINode *phi = Builder.CreatePHI(lhs.getAddress()->getType(), 2,
1979                                         "cond-lvalue");
1980  phi->addIncoming(lhs.getAddress(), lhsBlock);
1981  phi->addIncoming(rhs.getAddress(), rhsBlock);
1982  return MakeAddrLValue(phi, expr->getType());
1983}
1984
1985/// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
1986/// If the cast is a dynamic_cast, we can have the usual lvalue result,
1987/// otherwise if a cast is needed by the code generator in an lvalue context,
1988/// then it must mean that we need the address of an aggregate in order to
1989/// access one of its fields.  This can happen for all the reasons that casts
1990/// are permitted with aggregate result, including noop aggregate casts, and
1991/// cast from scalar to union.
1992LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
1993  switch (E->getCastKind()) {
1994  case CK_ToVoid:
1995    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
1996
1997  case CK_Dependent:
1998    llvm_unreachable("dependent cast kind in IR gen!");
1999
2000  case CK_GetObjCProperty: {
2001    LValue LV = EmitLValue(E->getSubExpr());
2002    assert(LV.isPropertyRef());
2003    RValue RV = EmitLoadOfPropertyRefLValue(LV);
2004
2005    // Property is an aggregate r-value.
2006    if (RV.isAggregate()) {
2007      return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2008    }
2009
2010    // Implicit property returns an l-value.
2011    assert(RV.isScalar());
2012    return MakeAddrLValue(RV.getScalarVal(), E->getSubExpr()->getType());
2013  }
2014
2015  case CK_NoOp:
2016  case CK_LValueToRValue:
2017    if (!E->getSubExpr()->Classify(getContext()).isPRValue()
2018        || E->getType()->isRecordType())
2019      return EmitLValue(E->getSubExpr());
2020    // Fall through to synthesize a temporary.
2021
2022  case CK_BitCast:
2023  case CK_ArrayToPointerDecay:
2024  case CK_FunctionToPointerDecay:
2025  case CK_NullToMemberPointer:
2026  case CK_NullToPointer:
2027  case CK_IntegralToPointer:
2028  case CK_PointerToIntegral:
2029  case CK_PointerToBoolean:
2030  case CK_VectorSplat:
2031  case CK_IntegralCast:
2032  case CK_IntegralToBoolean:
2033  case CK_IntegralToFloating:
2034  case CK_FloatingToIntegral:
2035  case CK_FloatingToBoolean:
2036  case CK_FloatingCast:
2037  case CK_FloatingRealToComplex:
2038  case CK_FloatingComplexToReal:
2039  case CK_FloatingComplexToBoolean:
2040  case CK_FloatingComplexCast:
2041  case CK_FloatingComplexToIntegralComplex:
2042  case CK_IntegralRealToComplex:
2043  case CK_IntegralComplexToReal:
2044  case CK_IntegralComplexToBoolean:
2045  case CK_IntegralComplexCast:
2046  case CK_IntegralComplexToFloatingComplex:
2047  case CK_DerivedToBaseMemberPointer:
2048  case CK_BaseToDerivedMemberPointer:
2049  case CK_MemberPointerToBoolean:
2050  case CK_AnyPointerToBlockPointerCast:
2051  case CK_ObjCProduceObject:
2052  case CK_ObjCConsumeObject:
2053  case CK_ObjCReclaimReturnedObject: {
2054    // These casts only produce lvalues when we're binding a reference to a
2055    // temporary realized from a (converted) pure rvalue. Emit the expression
2056    // as a value, copy it into a temporary, and return an lvalue referring to
2057    // that temporary.
2058    llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
2059    EmitAnyExprToMem(E, V, E->getType().getQualifiers(), false);
2060    return MakeAddrLValue(V, E->getType());
2061  }
2062
2063  case CK_Dynamic: {
2064    LValue LV = EmitLValue(E->getSubExpr());
2065    llvm::Value *V = LV.getAddress();
2066    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
2067    return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
2068  }
2069
2070  case CK_ConstructorConversion:
2071  case CK_UserDefinedConversion:
2072  case CK_AnyPointerToObjCPointerCast:
2073    return EmitLValue(E->getSubExpr());
2074
2075  case CK_UncheckedDerivedToBase:
2076  case CK_DerivedToBase: {
2077    const RecordType *DerivedClassTy =
2078      E->getSubExpr()->getType()->getAs<RecordType>();
2079    CXXRecordDecl *DerivedClassDecl =
2080      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2081
2082    LValue LV = EmitLValue(E->getSubExpr());
2083    llvm::Value *This = LV.getAddress();
2084
2085    // Perform the derived-to-base conversion
2086    llvm::Value *Base =
2087      GetAddressOfBaseClass(This, DerivedClassDecl,
2088                            E->path_begin(), E->path_end(),
2089                            /*NullCheckValue=*/false);
2090
2091    return MakeAddrLValue(Base, E->getType());
2092  }
2093  case CK_ToUnion:
2094    return EmitAggExprToLValue(E);
2095  case CK_BaseToDerived: {
2096    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
2097    CXXRecordDecl *DerivedClassDecl =
2098      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2099
2100    LValue LV = EmitLValue(E->getSubExpr());
2101
2102    // Perform the base-to-derived conversion
2103    llvm::Value *Derived =
2104      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
2105                               E->path_begin(), E->path_end(),
2106                               /*NullCheckValue=*/false);
2107
2108    return MakeAddrLValue(Derived, E->getType());
2109  }
2110  case CK_LValueBitCast: {
2111    // This must be a reinterpret_cast (or c-style equivalent).
2112    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
2113
2114    LValue LV = EmitLValue(E->getSubExpr());
2115    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2116                                           ConvertType(CE->getTypeAsWritten()));
2117    return MakeAddrLValue(V, E->getType());
2118  }
2119  case CK_ObjCObjectLValueCast: {
2120    LValue LV = EmitLValue(E->getSubExpr());
2121    QualType ToType = getContext().getLValueReferenceType(E->getType());
2122    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2123                                           ConvertType(ToType));
2124    return MakeAddrLValue(V, E->getType());
2125  }
2126  }
2127
2128  llvm_unreachable("Unhandled lvalue cast kind?");
2129}
2130
2131LValue CodeGenFunction::EmitNullInitializationLValue(
2132                                              const CXXScalarValueInitExpr *E) {
2133  QualType Ty = E->getType();
2134  LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
2135  EmitNullInitialization(LV.getAddress(), Ty);
2136  return LV;
2137}
2138
2139LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
2140  assert(e->isGLValue() || e->getType()->isRecordType());
2141  return getOpaqueLValueMapping(e);
2142}
2143
2144LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
2145                                           const MaterializeTemporaryExpr *E) {
2146  RValue RV = EmitReferenceBindingToExpr(E->GetTemporaryExpr(),
2147                                         /*InitializedDecl=*/0);
2148  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2149}
2150
2151
2152//===--------------------------------------------------------------------===//
2153//                             Expression Emission
2154//===--------------------------------------------------------------------===//
2155
2156RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
2157                                     ReturnValueSlot ReturnValue) {
2158  if (CGDebugInfo *DI = getDebugInfo()) {
2159    DI->setLocation(E->getLocStart());
2160    DI->UpdateLineDirectiveRegion(Builder);
2161    DI->EmitStopPoint(Builder);
2162  }
2163
2164  // Builtins never have block type.
2165  if (E->getCallee()->getType()->isBlockPointerType())
2166    return EmitBlockCallExpr(E, ReturnValue);
2167
2168  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
2169    return EmitCXXMemberCallExpr(CE, ReturnValue);
2170
2171  const Decl *TargetDecl = 0;
2172  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E->getCallee())) {
2173    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
2174      TargetDecl = DRE->getDecl();
2175      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(TargetDecl))
2176        if (unsigned builtinID = FD->getBuiltinID())
2177          return EmitBuiltinExpr(FD, builtinID, E);
2178    }
2179  }
2180
2181  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
2182    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
2183      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
2184
2185  if (const CXXPseudoDestructorExpr *PseudoDtor
2186          = dyn_cast<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
2187    QualType DestroyedType = PseudoDtor->getDestroyedType();
2188    if (getContext().getLangOptions().ObjCAutoRefCount &&
2189        DestroyedType->isObjCLifetimeType() &&
2190        (DestroyedType.getObjCLifetime() == Qualifiers::OCL_Strong ||
2191         DestroyedType.getObjCLifetime() == Qualifiers::OCL_Weak)) {
2192      // Automatic Reference Counting:
2193      //   If the pseudo-expression names a retainable object with weak or
2194      //   strong lifetime, the object shall be released.
2195      Expr *BaseExpr = PseudoDtor->getBase();
2196      llvm::Value *BaseValue = NULL;
2197      Qualifiers BaseQuals;
2198
2199      // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
2200      if (PseudoDtor->isArrow()) {
2201        BaseValue = EmitScalarExpr(BaseExpr);
2202        const PointerType *PTy = BaseExpr->getType()->getAs<PointerType>();
2203        BaseQuals = PTy->getPointeeType().getQualifiers();
2204      } else {
2205        LValue BaseLV = EmitLValue(BaseExpr);
2206        BaseValue = BaseLV.getAddress();
2207        QualType BaseTy = BaseExpr->getType();
2208        BaseQuals = BaseTy.getQualifiers();
2209      }
2210
2211      switch (PseudoDtor->getDestroyedType().getObjCLifetime()) {
2212      case Qualifiers::OCL_None:
2213      case Qualifiers::OCL_ExplicitNone:
2214      case Qualifiers::OCL_Autoreleasing:
2215        break;
2216
2217      case Qualifiers::OCL_Strong:
2218        EmitARCRelease(Builder.CreateLoad(BaseValue,
2219                          PseudoDtor->getDestroyedType().isVolatileQualified()),
2220                       /*precise*/ true);
2221        break;
2222
2223      case Qualifiers::OCL_Weak:
2224        EmitARCDestroyWeak(BaseValue);
2225        break;
2226      }
2227    } else {
2228      // C++ [expr.pseudo]p1:
2229      //   The result shall only be used as the operand for the function call
2230      //   operator (), and the result of such a call has type void. The only
2231      //   effect is the evaluation of the postfix-expression before the dot or
2232      //   arrow.
2233      EmitScalarExpr(E->getCallee());
2234    }
2235
2236    return RValue::get(0);
2237  }
2238
2239  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
2240  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
2241                  E->arg_begin(), E->arg_end(), TargetDecl);
2242}
2243
2244LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
2245  // Comma expressions just emit their LHS then their RHS as an l-value.
2246  if (E->getOpcode() == BO_Comma) {
2247    EmitIgnoredExpr(E->getLHS());
2248    EnsureInsertPoint();
2249    return EmitLValue(E->getRHS());
2250  }
2251
2252  if (E->getOpcode() == BO_PtrMemD ||
2253      E->getOpcode() == BO_PtrMemI)
2254    return EmitPointerToDataMemberBinaryExpr(E);
2255
2256  assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
2257
2258  // Note that in all of these cases, __block variables need the RHS
2259  // evaluated first just in case the variable gets moved by the RHS.
2260
2261  if (!hasAggregateLLVMType(E->getType())) {
2262    switch (E->getLHS()->getType().getObjCLifetime()) {
2263    case Qualifiers::OCL_Strong:
2264      return EmitARCStoreStrong(E, /*ignored*/ false).first;
2265
2266    case Qualifiers::OCL_Autoreleasing:
2267      return EmitARCStoreAutoreleasing(E).first;
2268
2269    // No reason to do any of these differently.
2270    case Qualifiers::OCL_None:
2271    case Qualifiers::OCL_ExplicitNone:
2272    case Qualifiers::OCL_Weak:
2273      break;
2274    }
2275
2276    RValue RV = EmitAnyExpr(E->getRHS());
2277    LValue LV = EmitLValue(E->getLHS());
2278    EmitStoreThroughLValue(RV, LV);
2279    return LV;
2280  }
2281
2282  if (E->getType()->isAnyComplexType())
2283    return EmitComplexAssignmentLValue(E);
2284
2285  return EmitAggExprToLValue(E);
2286}
2287
2288LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
2289  RValue RV = EmitCallExpr(E);
2290
2291  if (!RV.isScalar())
2292    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2293
2294  assert(E->getCallReturnType()->isReferenceType() &&
2295         "Can't have a scalar return unless the return type is a "
2296         "reference type!");
2297
2298  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2299}
2300
2301LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
2302  // FIXME: This shouldn't require another copy.
2303  return EmitAggExprToLValue(E);
2304}
2305
2306LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
2307  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
2308         && "binding l-value to type which needs a temporary");
2309  AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
2310  EmitCXXConstructExpr(E, Slot);
2311  return MakeAddrLValue(Slot.getAddr(), E->getType());
2312}
2313
2314LValue
2315CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
2316  return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
2317}
2318
2319LValue
2320CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
2321  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
2322  Slot.setLifetimeExternallyManaged();
2323  EmitAggExpr(E->getSubExpr(), Slot);
2324  EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
2325  return MakeAddrLValue(Slot.getAddr(), E->getType());
2326}
2327
2328LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
2329  RValue RV = EmitObjCMessageExpr(E);
2330
2331  if (!RV.isScalar())
2332    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2333
2334  assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
2335         "Can't have a scalar return unless the return type is a "
2336         "reference type!");
2337
2338  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2339}
2340
2341LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
2342  llvm::Value *V =
2343    CGM.getObjCRuntime().GetSelector(Builder, E->getSelector(), true);
2344  return MakeAddrLValue(V, E->getType());
2345}
2346
2347llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
2348                                             const ObjCIvarDecl *Ivar) {
2349  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
2350}
2351
2352LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
2353                                          llvm::Value *BaseValue,
2354                                          const ObjCIvarDecl *Ivar,
2355                                          unsigned CVRQualifiers) {
2356  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
2357                                                   Ivar, CVRQualifiers);
2358}
2359
2360LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
2361  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
2362  llvm::Value *BaseValue = 0;
2363  const Expr *BaseExpr = E->getBase();
2364  Qualifiers BaseQuals;
2365  QualType ObjectTy;
2366  if (E->isArrow()) {
2367    BaseValue = EmitScalarExpr(BaseExpr);
2368    ObjectTy = BaseExpr->getType()->getPointeeType();
2369    BaseQuals = ObjectTy.getQualifiers();
2370  } else {
2371    LValue BaseLV = EmitLValue(BaseExpr);
2372    // FIXME: this isn't right for bitfields.
2373    BaseValue = BaseLV.getAddress();
2374    ObjectTy = BaseExpr->getType();
2375    BaseQuals = ObjectTy.getQualifiers();
2376  }
2377
2378  LValue LV =
2379    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
2380                      BaseQuals.getCVRQualifiers());
2381  setObjCGCLValueClass(getContext(), E, LV);
2382  return LV;
2383}
2384
2385LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
2386  // Can only get l-value for message expression returning aggregate type
2387  RValue RV = EmitAnyExprToTemp(E);
2388  return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2389}
2390
2391RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
2392                                 ReturnValueSlot ReturnValue,
2393                                 CallExpr::const_arg_iterator ArgBeg,
2394                                 CallExpr::const_arg_iterator ArgEnd,
2395                                 const Decl *TargetDecl) {
2396  // Get the actual function type. The callee type will always be a pointer to
2397  // function type or a block pointer type.
2398  assert(CalleeType->isFunctionPointerType() &&
2399         "Call must have function pointer type!");
2400
2401  CalleeType = getContext().getCanonicalType(CalleeType);
2402
2403  const FunctionType *FnType
2404    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
2405
2406  CallArgList Args;
2407  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
2408
2409  return EmitCall(CGM.getTypes().getFunctionInfo(Args, FnType),
2410                  Callee, ReturnValue, Args, TargetDecl);
2411}
2412
2413LValue CodeGenFunction::
2414EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
2415  llvm::Value *BaseV;
2416  if (E->getOpcode() == BO_PtrMemI)
2417    BaseV = EmitScalarExpr(E->getLHS());
2418  else
2419    BaseV = EmitLValue(E->getLHS()).getAddress();
2420
2421  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
2422
2423  const MemberPointerType *MPT
2424    = E->getRHS()->getType()->getAs<MemberPointerType>();
2425
2426  llvm::Value *AddV =
2427    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
2428
2429  return MakeAddrLValue(AddV, MPT->getPointeeType());
2430}
2431