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 "TargetInfo.h"
22 #include "clang/AST/ASTContext.h"
23 #include "clang/AST/DeclObjC.h"
24 #include "clang/Frontend/CodeGenOptions.h"
25 #include "llvm/Intrinsics.h"
26 #include "llvm/LLVMContext.h"
27 #include "llvm/Target/TargetData.h"
28 using namespace clang;
29 using namespace CodeGen;
30 
31 //===--------------------------------------------------------------------===//
32 //                        Miscellaneous Helper Methods
33 //===--------------------------------------------------------------------===//
34 
35 llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
36   unsigned addressSpace =
37     cast<llvm::PointerType>(value->getType())->getAddressSpace();
38 
39   llvm::PointerType *destType = Int8PtrTy;
40   if (addressSpace)
41     destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
42 
43   if (value->getType() == destType) return value;
44   return Builder.CreateBitCast(value, destType);
45 }
46 
47 /// CreateTempAlloca - This creates a alloca and inserts it into the entry
48 /// block.
49 llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
50                                                     const Twine &Name) {
51   if (!Builder.isNamePreserving())
52     return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
53   return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
54 }
55 
56 void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
57                                      llvm::Value *Init) {
58   llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
59   llvm::BasicBlock *Block = AllocaInsertPt->getParent();
60   Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
61 }
62 
63 llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
64                                                 const Twine &Name) {
65   llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
66   // FIXME: Should we prefer the preferred type alignment here?
67   CharUnits Align = getContext().getTypeAlignInChars(Ty);
68   Alloc->setAlignment(Align.getQuantity());
69   return Alloc;
70 }
71 
72 llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
73                                                  const Twine &Name) {
74   llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
75   // FIXME: Should we prefer the preferred type alignment here?
76   CharUnits Align = getContext().getTypeAlignInChars(Ty);
77   Alloc->setAlignment(Align.getQuantity());
78   return Alloc;
79 }
80 
81 /// EvaluateExprAsBool - Perform the usual unary conversions on the specified
82 /// expression and compare the result against zero, returning an Int1Ty value.
83 llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
84   if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
85     llvm::Value *MemPtr = EmitScalarExpr(E);
86     return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT);
87   }
88 
89   QualType BoolTy = getContext().BoolTy;
90   if (!E->getType()->isAnyComplexType())
91     return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
92 
93   return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
94 }
95 
96 /// EmitIgnoredExpr - Emit code to compute the specified expression,
97 /// ignoring the result.
98 void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
99   if (E->isRValue())
100     return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
101 
102   // Just emit it as an l-value and drop the result.
103   EmitLValue(E);
104 }
105 
106 /// EmitAnyExpr - Emit code to compute the specified expression which
107 /// can have any type.  The result is returned as an RValue struct.
108 /// If this is an aggregate expression, AggSlot indicates where the
109 /// result should be returned.
110 RValue CodeGenFunction::EmitAnyExpr(const Expr *E, AggValueSlot AggSlot,
111                                     bool IgnoreResult) {
112   if (!hasAggregateLLVMType(E->getType()))
113     return RValue::get(EmitScalarExpr(E, IgnoreResult));
114   else if (E->getType()->isAnyComplexType())
115     return RValue::getComplex(EmitComplexExpr(E, IgnoreResult, IgnoreResult));
116 
117   EmitAggExpr(E, AggSlot, IgnoreResult);
118   return AggSlot.asRValue();
119 }
120 
121 /// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
122 /// always be accessible even if no aggregate location is provided.
123 RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
124   AggValueSlot AggSlot = AggValueSlot::ignored();
125 
126   if (hasAggregateLLVMType(E->getType()) &&
127       !E->getType()->isAnyComplexType())
128     AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
129   return EmitAnyExpr(E, AggSlot);
130 }
131 
132 /// EmitAnyExprToMem - Evaluate an expression into a given memory
133 /// location.
134 void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
135                                        llvm::Value *Location,
136                                        Qualifiers Quals,
137                                        bool IsInit) {
138   if (E->getType()->isAnyComplexType())
139     EmitComplexExprIntoAddr(E, Location, Quals.hasVolatile());
140   else if (hasAggregateLLVMType(E->getType()))
141     EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals,
142                                          AggValueSlot::IsDestructed_t(IsInit),
143                                          AggValueSlot::DoesNotNeedGCBarriers,
144                                          AggValueSlot::IsAliased_t(!IsInit)));
145   else {
146     RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
147     LValue LV = MakeAddrLValue(Location, E->getType());
148     EmitStoreThroughLValue(RV, LV);
149   }
150 }
151 
152 namespace {
153 /// \brief An adjustment to be made to the temporary created when emitting a
154 /// reference binding, which accesses a particular subobject of that temporary.
155   struct SubobjectAdjustment {
156     enum { DerivedToBaseAdjustment, FieldAdjustment } Kind;
157 
158     union {
159       struct {
160         const CastExpr *BasePath;
161         const CXXRecordDecl *DerivedClass;
162       } DerivedToBase;
163 
164       FieldDecl *Field;
165     };
166 
167     SubobjectAdjustment(const CastExpr *BasePath,
168                         const CXXRecordDecl *DerivedClass)
169       : Kind(DerivedToBaseAdjustment) {
170       DerivedToBase.BasePath = BasePath;
171       DerivedToBase.DerivedClass = DerivedClass;
172     }
173 
174     SubobjectAdjustment(FieldDecl *Field)
175       : Kind(FieldAdjustment) {
176       this->Field = Field;
177     }
178   };
179 }
180 
181 static llvm::Value *
182 CreateReferenceTemporary(CodeGenFunction &CGF, QualType Type,
183                          const NamedDecl *InitializedDecl) {
184   if (const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
185     if (VD->hasGlobalStorage()) {
186       llvm::SmallString<256> Name;
187       llvm::raw_svector_ostream Out(Name);
188       CGF.CGM.getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Out);
189       Out.flush();
190 
191       llvm::Type *RefTempTy = CGF.ConvertTypeForMem(Type);
192 
193       // Create the reference temporary.
194       llvm::GlobalValue *RefTemp =
195         new llvm::GlobalVariable(CGF.CGM.getModule(),
196                                  RefTempTy, /*isConstant=*/false,
197                                  llvm::GlobalValue::InternalLinkage,
198                                  llvm::Constant::getNullValue(RefTempTy),
199                                  Name.str());
200       return RefTemp;
201     }
202   }
203 
204   return CGF.CreateMemTemp(Type, "ref.tmp");
205 }
206 
207 static llvm::Value *
208 EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
209                             llvm::Value *&ReferenceTemporary,
210                             const CXXDestructorDecl *&ReferenceTemporaryDtor,
211                             QualType &ObjCARCReferenceLifetimeType,
212                             const NamedDecl *InitializedDecl) {
213   // Look through expressions for materialized temporaries (for now).
214   if (const MaterializeTemporaryExpr *M
215                                       = dyn_cast<MaterializeTemporaryExpr>(E)) {
216     // Objective-C++ ARC:
217     //   If we are binding a reference to a temporary that has ownership, we
218     //   need to perform retain/release operations on the temporary.
219     if (CGF.getContext().getLangOptions().ObjCAutoRefCount &&
220         E->getType()->isObjCLifetimeType() &&
221         (E->getType().getObjCLifetime() == Qualifiers::OCL_Strong ||
222          E->getType().getObjCLifetime() == Qualifiers::OCL_Weak ||
223          E->getType().getObjCLifetime() == Qualifiers::OCL_Autoreleasing))
224       ObjCARCReferenceLifetimeType = E->getType();
225 
226     E = M->GetTemporaryExpr();
227   }
228 
229   if (const CXXDefaultArgExpr *DAE = dyn_cast<CXXDefaultArgExpr>(E))
230     E = DAE->getExpr();
231 
232   if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(E)) {
233     CGF.enterFullExpression(EWC);
234     CodeGenFunction::RunCleanupsScope Scope(CGF);
235 
236     return EmitExprForReferenceBinding(CGF, EWC->getSubExpr(),
237                                        ReferenceTemporary,
238                                        ReferenceTemporaryDtor,
239                                        ObjCARCReferenceLifetimeType,
240                                        InitializedDecl);
241   }
242 
243   RValue RV;
244   if (E->isGLValue()) {
245     // Emit the expression as an lvalue.
246     LValue LV = CGF.EmitLValue(E);
247 
248     if (LV.isSimple())
249       return LV.getAddress();
250 
251     // We have to load the lvalue.
252     RV = CGF.EmitLoadOfLValue(LV);
253   } else {
254     if (!ObjCARCReferenceLifetimeType.isNull()) {
255       ReferenceTemporary = CreateReferenceTemporary(CGF,
256                                                   ObjCARCReferenceLifetimeType,
257                                                     InitializedDecl);
258 
259 
260       LValue RefTempDst = CGF.MakeAddrLValue(ReferenceTemporary,
261                                              ObjCARCReferenceLifetimeType);
262 
263       CGF.EmitScalarInit(E, dyn_cast_or_null<ValueDecl>(InitializedDecl),
264                          RefTempDst, false);
265 
266       bool ExtendsLifeOfTemporary = false;
267       if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(InitializedDecl)) {
268         if (Var->extendsLifetimeOfTemporary())
269           ExtendsLifeOfTemporary = true;
270       } else if (InitializedDecl && isa<FieldDecl>(InitializedDecl)) {
271         ExtendsLifeOfTemporary = true;
272       }
273 
274       if (!ExtendsLifeOfTemporary) {
275         // Since the lifetime of this temporary isn't going to be extended,
276         // we need to clean it up ourselves at the end of the full expression.
277         switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
278         case Qualifiers::OCL_None:
279         case Qualifiers::OCL_ExplicitNone:
280         case Qualifiers::OCL_Autoreleasing:
281           break;
282 
283         case Qualifiers::OCL_Strong: {
284           assert(!ObjCARCReferenceLifetimeType->isArrayType());
285           CleanupKind cleanupKind = CGF.getARCCleanupKind();
286           CGF.pushDestroy(cleanupKind,
287                           ReferenceTemporary,
288                           ObjCARCReferenceLifetimeType,
289                           CodeGenFunction::destroyARCStrongImprecise,
290                           cleanupKind & EHCleanup);
291           break;
292         }
293 
294         case Qualifiers::OCL_Weak:
295           assert(!ObjCARCReferenceLifetimeType->isArrayType());
296           CGF.pushDestroy(NormalAndEHCleanup,
297                           ReferenceTemporary,
298                           ObjCARCReferenceLifetimeType,
299                           CodeGenFunction::destroyARCWeak,
300                           /*useEHCleanupForArray*/ true);
301           break;
302         }
303 
304         ObjCARCReferenceLifetimeType = QualType();
305       }
306 
307       return ReferenceTemporary;
308     }
309 
310     SmallVector<SubobjectAdjustment, 2> Adjustments;
311     while (true) {
312       E = E->IgnoreParens();
313 
314       if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
315         if ((CE->getCastKind() == CK_DerivedToBase ||
316              CE->getCastKind() == CK_UncheckedDerivedToBase) &&
317             E->getType()->isRecordType()) {
318           E = CE->getSubExpr();
319           CXXRecordDecl *Derived
320             = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
321           Adjustments.push_back(SubobjectAdjustment(CE, Derived));
322           continue;
323         }
324 
325         if (CE->getCastKind() == CK_NoOp) {
326           E = CE->getSubExpr();
327           continue;
328         }
329       } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
330         if (!ME->isArrow() && ME->getBase()->isRValue()) {
331           assert(ME->getBase()->getType()->isRecordType());
332           if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
333             E = ME->getBase();
334             Adjustments.push_back(SubobjectAdjustment(Field));
335             continue;
336           }
337         }
338       }
339 
340       if (const OpaqueValueExpr *opaque = dyn_cast<OpaqueValueExpr>(E))
341         if (opaque->getType()->isRecordType())
342           return CGF.EmitOpaqueValueLValue(opaque).getAddress();
343 
344       // Nothing changed.
345       break;
346     }
347 
348     // Create a reference temporary if necessary.
349     AggValueSlot AggSlot = AggValueSlot::ignored();
350     if (CGF.hasAggregateLLVMType(E->getType()) &&
351         !E->getType()->isAnyComplexType()) {
352       ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
353                                                     InitializedDecl);
354       AggValueSlot::IsDestructed_t isDestructed
355         = AggValueSlot::IsDestructed_t(InitializedDecl != 0);
356       AggSlot = AggValueSlot::forAddr(ReferenceTemporary, Qualifiers(),
357                                       isDestructed,
358                                       AggValueSlot::DoesNotNeedGCBarriers,
359                                       AggValueSlot::IsNotAliased);
360     }
361 
362     if (InitializedDecl) {
363       // Get the destructor for the reference temporary.
364       if (const RecordType *RT = E->getType()->getAs<RecordType>()) {
365         CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
366         if (!ClassDecl->hasTrivialDestructor())
367           ReferenceTemporaryDtor = ClassDecl->getDestructor();
368       }
369     }
370 
371     RV = CGF.EmitAnyExpr(E, AggSlot);
372 
373     // Check if need to perform derived-to-base casts and/or field accesses, to
374     // get from the temporary object we created (and, potentially, for which we
375     // extended the lifetime) to the subobject we're binding the reference to.
376     if (!Adjustments.empty()) {
377       llvm::Value *Object = RV.getAggregateAddr();
378       for (unsigned I = Adjustments.size(); I != 0; --I) {
379         SubobjectAdjustment &Adjustment = Adjustments[I-1];
380         switch (Adjustment.Kind) {
381         case SubobjectAdjustment::DerivedToBaseAdjustment:
382           Object =
383               CGF.GetAddressOfBaseClass(Object,
384                                         Adjustment.DerivedToBase.DerivedClass,
385                               Adjustment.DerivedToBase.BasePath->path_begin(),
386                               Adjustment.DerivedToBase.BasePath->path_end(),
387                                         /*NullCheckValue=*/false);
388           break;
389 
390         case SubobjectAdjustment::FieldAdjustment: {
391           LValue LV =
392             CGF.EmitLValueForField(Object, Adjustment.Field, 0);
393           if (LV.isSimple()) {
394             Object = LV.getAddress();
395             break;
396           }
397 
398           // For non-simple lvalues, we actually have to create a copy of
399           // the object we're binding to.
400           QualType T = Adjustment.Field->getType().getNonReferenceType()
401                                                   .getUnqualifiedType();
402           Object = CreateReferenceTemporary(CGF, T, InitializedDecl);
403           LValue TempLV = CGF.MakeAddrLValue(Object,
404                                              Adjustment.Field->getType());
405           CGF.EmitStoreThroughLValue(CGF.EmitLoadOfLValue(LV), TempLV);
406           break;
407         }
408 
409         }
410       }
411 
412       return Object;
413     }
414   }
415 
416   if (RV.isAggregate())
417     return RV.getAggregateAddr();
418 
419   // Create a temporary variable that we can bind the reference to.
420   ReferenceTemporary = CreateReferenceTemporary(CGF, E->getType(),
421                                                 InitializedDecl);
422 
423 
424   unsigned Alignment =
425     CGF.getContext().getTypeAlignInChars(E->getType()).getQuantity();
426   if (RV.isScalar())
427     CGF.EmitStoreOfScalar(RV.getScalarVal(), ReferenceTemporary,
428                           /*Volatile=*/false, Alignment, E->getType());
429   else
430     CGF.StoreComplexToAddr(RV.getComplexVal(), ReferenceTemporary,
431                            /*Volatile=*/false);
432   return ReferenceTemporary;
433 }
434 
435 RValue
436 CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E,
437                                             const NamedDecl *InitializedDecl) {
438   llvm::Value *ReferenceTemporary = 0;
439   const CXXDestructorDecl *ReferenceTemporaryDtor = 0;
440   QualType ObjCARCReferenceLifetimeType;
441   llvm::Value *Value = EmitExprForReferenceBinding(*this, E, ReferenceTemporary,
442                                                    ReferenceTemporaryDtor,
443                                                    ObjCARCReferenceLifetimeType,
444                                                    InitializedDecl);
445   if (!ReferenceTemporaryDtor && ObjCARCReferenceLifetimeType.isNull())
446     return RValue::get(Value);
447 
448   // Make sure to call the destructor for the reference temporary.
449   const VarDecl *VD = dyn_cast_or_null<VarDecl>(InitializedDecl);
450   if (VD && VD->hasGlobalStorage()) {
451     if (ReferenceTemporaryDtor) {
452       llvm::Constant *DtorFn =
453         CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
454       EmitCXXGlobalDtorRegistration(DtorFn,
455                                     cast<llvm::Constant>(ReferenceTemporary));
456     } else {
457       assert(!ObjCARCReferenceLifetimeType.isNull());
458       // Note: We intentionally do not register a global "destructor" to
459       // release the object.
460     }
461 
462     return RValue::get(Value);
463   }
464 
465   if (ReferenceTemporaryDtor)
466     PushDestructorCleanup(ReferenceTemporaryDtor, ReferenceTemporary);
467   else {
468     switch (ObjCARCReferenceLifetimeType.getObjCLifetime()) {
469     case Qualifiers::OCL_None:
470       llvm_unreachable(
471                       "Not a reference temporary that needs to be deallocated");
472     case Qualifiers::OCL_ExplicitNone:
473     case Qualifiers::OCL_Autoreleasing:
474       // Nothing to do.
475       break;
476 
477     case Qualifiers::OCL_Strong: {
478       bool precise = VD && VD->hasAttr<ObjCPreciseLifetimeAttr>();
479       CleanupKind cleanupKind = getARCCleanupKind();
480       // This local is a GCC and MSVC compiler workaround.
481       Destroyer *destroyer = precise ? &destroyARCStrongPrecise :
482                                        &destroyARCStrongImprecise;
483       pushDestroy(cleanupKind, ReferenceTemporary, ObjCARCReferenceLifetimeType,
484                   *destroyer, cleanupKind & EHCleanup);
485       break;
486     }
487 
488     case Qualifiers::OCL_Weak: {
489       // This local is a GCC and MSVC compiler workaround.
490       Destroyer *destroyer = &destroyARCWeak;
491       // __weak objects always get EH cleanups; otherwise, exceptions
492       // could cause really nasty crashes instead of mere leaks.
493       pushDestroy(NormalAndEHCleanup, ReferenceTemporary,
494                   ObjCARCReferenceLifetimeType, *destroyer, true);
495       break;
496     }
497     }
498   }
499 
500   return RValue::get(Value);
501 }
502 
503 
504 /// getAccessedFieldNo - Given an encoded value and a result number, return the
505 /// input field number being accessed.
506 unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
507                                              const llvm::Constant *Elts) {
508   if (isa<llvm::ConstantAggregateZero>(Elts))
509     return 0;
510 
511   return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
512 }
513 
514 void CodeGenFunction::EmitCheck(llvm::Value *Address, unsigned Size) {
515   if (!CatchUndefined)
516     return;
517 
518   // This needs to be to the standard address space.
519   Address = Builder.CreateBitCast(Address, Int8PtrTy);
520 
521   llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, IntPtrTy);
522 
523   // In time, people may want to control this and use a 1 here.
524   llvm::Value *Arg = Builder.getFalse();
525   llvm::Value *C = Builder.CreateCall2(F, Address, Arg);
526   llvm::BasicBlock *Cont = createBasicBlock();
527   llvm::BasicBlock *Check = createBasicBlock();
528   llvm::Value *NegativeOne = llvm::ConstantInt::get(IntPtrTy, -1ULL);
529   Builder.CreateCondBr(Builder.CreateICmpEQ(C, NegativeOne), Cont, Check);
530 
531   EmitBlock(Check);
532   Builder.CreateCondBr(Builder.CreateICmpUGE(C,
533                                         llvm::ConstantInt::get(IntPtrTy, Size)),
534                        Cont, getTrapBB());
535   EmitBlock(Cont);
536 }
537 
538 
539 CodeGenFunction::ComplexPairTy CodeGenFunction::
540 EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
541                          bool isInc, bool isPre) {
542   ComplexPairTy InVal = LoadComplexFromAddr(LV.getAddress(),
543                                             LV.isVolatileQualified());
544 
545   llvm::Value *NextVal;
546   if (isa<llvm::IntegerType>(InVal.first->getType())) {
547     uint64_t AmountVal = isInc ? 1 : -1;
548     NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
549 
550     // Add the inc/dec to the real part.
551     NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
552   } else {
553     QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
554     llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
555     if (!isInc)
556       FVal.changeSign();
557     NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
558 
559     // Add the inc/dec to the real part.
560     NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
561   }
562 
563   ComplexPairTy IncVal(NextVal, InVal.second);
564 
565   // Store the updated result through the lvalue.
566   StoreComplexToAddr(IncVal, LV.getAddress(), LV.isVolatileQualified());
567 
568   // If this is a postinc, return the value read from memory, otherwise use the
569   // updated value.
570   return isPre ? IncVal : InVal;
571 }
572 
573 
574 //===----------------------------------------------------------------------===//
575 //                         LValue Expression Emission
576 //===----------------------------------------------------------------------===//
577 
578 RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
579   if (Ty->isVoidType())
580     return RValue::get(0);
581 
582   if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
583     llvm::Type *EltTy = ConvertType(CTy->getElementType());
584     llvm::Value *U = llvm::UndefValue::get(EltTy);
585     return RValue::getComplex(std::make_pair(U, U));
586   }
587 
588   // If this is a use of an undefined aggregate type, the aggregate must have an
589   // identifiable address.  Just because the contents of the value are undefined
590   // doesn't mean that the address can't be taken and compared.
591   if (hasAggregateLLVMType(Ty)) {
592     llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
593     return RValue::getAggregate(DestPtr);
594   }
595 
596   return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
597 }
598 
599 RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
600                                               const char *Name) {
601   ErrorUnsupported(E, Name);
602   return GetUndefRValue(E->getType());
603 }
604 
605 LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
606                                               const char *Name) {
607   ErrorUnsupported(E, Name);
608   llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
609   return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
610 }
611 
612 LValue CodeGenFunction::EmitCheckedLValue(const Expr *E) {
613   LValue LV = EmitLValue(E);
614   if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
615     EmitCheck(LV.getAddress(),
616               getContext().getTypeSizeInChars(E->getType()).getQuantity());
617   return LV;
618 }
619 
620 /// EmitLValue - Emit code to compute a designator that specifies the location
621 /// of the expression.
622 ///
623 /// This can return one of two things: a simple address or a bitfield reference.
624 /// In either case, the LLVM Value* in the LValue structure is guaranteed to be
625 /// an LLVM pointer type.
626 ///
627 /// If this returns a bitfield reference, nothing about the pointee type of the
628 /// LLVM value is known: For example, it may not be a pointer to an integer.
629 ///
630 /// If this returns a normal address, and if the lvalue's C type is fixed size,
631 /// this method guarantees that the returned pointer type will point to an LLVM
632 /// type of the same size of the lvalue's type.  If the lvalue has a variable
633 /// length type, this is not possible.
634 ///
635 LValue CodeGenFunction::EmitLValue(const Expr *E) {
636   switch (E->getStmtClass()) {
637   default: return EmitUnsupportedLValue(E, "l-value expression");
638 
639   case Expr::ObjCPropertyRefExprClass:
640     llvm_unreachable("cannot emit a property reference directly");
641 
642   case Expr::ObjCSelectorExprClass:
643   return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
644   case Expr::ObjCIsaExprClass:
645     return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
646   case Expr::BinaryOperatorClass:
647     return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
648   case Expr::CompoundAssignOperatorClass:
649     if (!E->getType()->isAnyComplexType())
650       return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
651     return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
652   case Expr::CallExprClass:
653   case Expr::CXXMemberCallExprClass:
654   case Expr::CXXOperatorCallExprClass:
655     return EmitCallExprLValue(cast<CallExpr>(E));
656   case Expr::VAArgExprClass:
657     return EmitVAArgExprLValue(cast<VAArgExpr>(E));
658   case Expr::DeclRefExprClass:
659     return EmitDeclRefLValue(cast<DeclRefExpr>(E));
660   case Expr::ParenExprClass:
661     return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
662   case Expr::GenericSelectionExprClass:
663     return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
664   case Expr::PredefinedExprClass:
665     return EmitPredefinedLValue(cast<PredefinedExpr>(E));
666   case Expr::StringLiteralClass:
667     return EmitStringLiteralLValue(cast<StringLiteral>(E));
668   case Expr::ObjCEncodeExprClass:
669     return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
670   case Expr::PseudoObjectExprClass:
671     return EmitPseudoObjectLValue(cast<PseudoObjectExpr>(E));
672 
673   case Expr::BlockDeclRefExprClass:
674     return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
675 
676   case Expr::CXXTemporaryObjectExprClass:
677   case Expr::CXXConstructExprClass:
678     return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
679   case Expr::CXXBindTemporaryExprClass:
680     return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
681 
682   case Expr::ExprWithCleanupsClass: {
683     const ExprWithCleanups *cleanups = cast<ExprWithCleanups>(E);
684     enterFullExpression(cleanups);
685     RunCleanupsScope Scope(*this);
686     return EmitLValue(cleanups->getSubExpr());
687   }
688 
689   case Expr::CXXScalarValueInitExprClass:
690     return EmitNullInitializationLValue(cast<CXXScalarValueInitExpr>(E));
691   case Expr::CXXDefaultArgExprClass:
692     return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
693   case Expr::CXXTypeidExprClass:
694     return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
695 
696   case Expr::ObjCMessageExprClass:
697     return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
698   case Expr::ObjCIvarRefExprClass:
699     return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
700   case Expr::StmtExprClass:
701     return EmitStmtExprLValue(cast<StmtExpr>(E));
702   case Expr::UnaryOperatorClass:
703     return EmitUnaryOpLValue(cast<UnaryOperator>(E));
704   case Expr::ArraySubscriptExprClass:
705     return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
706   case Expr::ExtVectorElementExprClass:
707     return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
708   case Expr::MemberExprClass:
709     return EmitMemberExpr(cast<MemberExpr>(E));
710   case Expr::CompoundLiteralExprClass:
711     return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
712   case Expr::ConditionalOperatorClass:
713     return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
714   case Expr::BinaryConditionalOperatorClass:
715     return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
716   case Expr::ChooseExprClass:
717     return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr(getContext()));
718   case Expr::OpaqueValueExprClass:
719     return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
720   case Expr::SubstNonTypeTemplateParmExprClass:
721     return EmitLValue(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
722   case Expr::ImplicitCastExprClass:
723   case Expr::CStyleCastExprClass:
724   case Expr::CXXFunctionalCastExprClass:
725   case Expr::CXXStaticCastExprClass:
726   case Expr::CXXDynamicCastExprClass:
727   case Expr::CXXReinterpretCastExprClass:
728   case Expr::CXXConstCastExprClass:
729   case Expr::ObjCBridgedCastExprClass:
730     return EmitCastLValue(cast<CastExpr>(E));
731 
732   case Expr::MaterializeTemporaryExprClass:
733     return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
734   }
735 }
736 
737 llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue) {
738   return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
739                           lvalue.getAlignment(), lvalue.getType(),
740                           lvalue.getTBAAInfo());
741 }
742 
743 llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
744                                               unsigned Alignment, QualType Ty,
745                                               llvm::MDNode *TBAAInfo) {
746   llvm::LoadInst *Load = Builder.CreateLoad(Addr);
747   if (Volatile)
748     Load->setVolatile(true);
749   if (Alignment)
750     Load->setAlignment(Alignment);
751   if (TBAAInfo)
752     CGM.DecorateInstruction(Load, TBAAInfo);
753 
754   return EmitFromMemory(Load, Ty);
755 }
756 
757 static bool isBooleanUnderlyingType(QualType Ty) {
758   if (const EnumType *ET = dyn_cast<EnumType>(Ty))
759     return ET->getDecl()->getIntegerType()->isBooleanType();
760   return false;
761 }
762 
763 llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
764   // Bool has a different representation in memory than in registers.
765   if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
766     // This should really always be an i1, but sometimes it's already
767     // an i8, and it's awkward to track those cases down.
768     if (Value->getType()->isIntegerTy(1))
769       return Builder.CreateZExt(Value, Builder.getInt8Ty(), "frombool");
770     assert(Value->getType()->isIntegerTy(8) && "value rep of bool not i1/i8");
771   }
772 
773   return Value;
774 }
775 
776 llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
777   // Bool has a different representation in memory than in registers.
778   if (Ty->isBooleanType() || isBooleanUnderlyingType(Ty)) {
779     assert(Value->getType()->isIntegerTy(8) && "memory rep of bool not i8");
780     return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
781   }
782 
783   return Value;
784 }
785 
786 void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
787                                         bool Volatile, unsigned Alignment,
788                                         QualType Ty,
789                                         llvm::MDNode *TBAAInfo) {
790   Value = EmitToMemory(Value, Ty);
791 
792   llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
793   if (Alignment)
794     Store->setAlignment(Alignment);
795   if (TBAAInfo)
796     CGM.DecorateInstruction(Store, TBAAInfo);
797 }
798 
799 void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue) {
800   EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
801                     lvalue.getAlignment(), lvalue.getType(),
802                     lvalue.getTBAAInfo());
803 }
804 
805 /// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
806 /// method emits the address of the lvalue, then loads the result as an rvalue,
807 /// returning the rvalue.
808 RValue CodeGenFunction::EmitLoadOfLValue(LValue LV) {
809   if (LV.isObjCWeak()) {
810     // load of a __weak object.
811     llvm::Value *AddrWeakObj = LV.getAddress();
812     return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
813                                                              AddrWeakObj));
814   }
815   if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak)
816     return RValue::get(EmitARCLoadWeak(LV.getAddress()));
817 
818   if (LV.isSimple()) {
819     assert(!LV.getType()->isFunctionType());
820 
821     // Everything needs a load.
822     return RValue::get(EmitLoadOfScalar(LV));
823   }
824 
825   if (LV.isVectorElt()) {
826     llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
827                                           LV.isVolatileQualified());
828     return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
829                                                     "vecext"));
830   }
831 
832   // If this is a reference to a subset of the elements of a vector, either
833   // shuffle the input or extract/insert them as appropriate.
834   if (LV.isExtVectorElt())
835     return EmitLoadOfExtVectorElementLValue(LV);
836 
837   assert(LV.isBitField() && "Unknown LValue type!");
838   return EmitLoadOfBitfieldLValue(LV);
839 }
840 
841 RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV) {
842   const CGBitFieldInfo &Info = LV.getBitFieldInfo();
843 
844   // Get the output type.
845   llvm::Type *ResLTy = ConvertType(LV.getType());
846   unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
847 
848   // Compute the result as an OR of all of the individual component accesses.
849   llvm::Value *Res = 0;
850   for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
851     const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
852 
853     // Get the field pointer.
854     llvm::Value *Ptr = LV.getBitFieldBaseAddr();
855 
856     // Only offset by the field index if used, so that incoming values are not
857     // required to be structures.
858     if (AI.FieldIndex)
859       Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
860 
861     // Offset by the byte offset, if used.
862     if (!AI.FieldByteOffset.isZero()) {
863       Ptr = EmitCastToVoidPtr(Ptr);
864       Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
865                                        "bf.field.offs");
866     }
867 
868     // Cast to the access type.
869     llvm::Type *PTy = llvm::Type::getIntNPtrTy(getLLVMContext(),
870                                                      AI.AccessWidth,
871                        CGM.getContext().getTargetAddressSpace(LV.getType()));
872     Ptr = Builder.CreateBitCast(Ptr, PTy);
873 
874     // Perform the load.
875     llvm::LoadInst *Load = Builder.CreateLoad(Ptr, LV.isVolatileQualified());
876     if (!AI.AccessAlignment.isZero())
877       Load->setAlignment(AI.AccessAlignment.getQuantity());
878 
879     // Shift out unused low bits and mask out unused high bits.
880     llvm::Value *Val = Load;
881     if (AI.FieldBitStart)
882       Val = Builder.CreateLShr(Load, AI.FieldBitStart);
883     Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(AI.AccessWidth,
884                                                             AI.TargetBitWidth),
885                             "bf.clear");
886 
887     // Extend or truncate to the target size.
888     if (AI.AccessWidth < ResSizeInBits)
889       Val = Builder.CreateZExt(Val, ResLTy);
890     else if (AI.AccessWidth > ResSizeInBits)
891       Val = Builder.CreateTrunc(Val, ResLTy);
892 
893     // Shift into place, and OR into the result.
894     if (AI.TargetBitOffset)
895       Val = Builder.CreateShl(Val, AI.TargetBitOffset);
896     Res = Res ? Builder.CreateOr(Res, Val) : Val;
897   }
898 
899   // If the bit-field is signed, perform the sign-extension.
900   //
901   // FIXME: This can easily be folded into the load of the high bits, which
902   // could also eliminate the mask of high bits in some situations.
903   if (Info.isSigned()) {
904     unsigned ExtraBits = ResSizeInBits - Info.getSize();
905     if (ExtraBits)
906       Res = Builder.CreateAShr(Builder.CreateShl(Res, ExtraBits),
907                                ExtraBits, "bf.val.sext");
908   }
909 
910   return RValue::get(Res);
911 }
912 
913 // If this is a reference to a subset of the elements of a vector, create an
914 // appropriate shufflevector.
915 RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) {
916   llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
917                                         LV.isVolatileQualified());
918 
919   const llvm::Constant *Elts = LV.getExtVectorElts();
920 
921   // If the result of the expression is a non-vector type, we must be extracting
922   // a single element.  Just codegen as an extractelement.
923   const VectorType *ExprVT = LV.getType()->getAs<VectorType>();
924   if (!ExprVT) {
925     unsigned InIdx = getAccessedFieldNo(0, Elts);
926     llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
927     return RValue::get(Builder.CreateExtractElement(Vec, Elt));
928   }
929 
930   // Always use shuffle vector to try to retain the original program structure
931   unsigned NumResultElts = ExprVT->getNumElements();
932 
933   SmallVector<llvm::Constant*, 4> Mask;
934   for (unsigned i = 0; i != NumResultElts; ++i) {
935     unsigned InIdx = getAccessedFieldNo(i, Elts);
936     Mask.push_back(llvm::ConstantInt::get(Int32Ty, InIdx));
937   }
938 
939   llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
940   Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()),
941                                     MaskV);
942   return RValue::get(Vec);
943 }
944 
945 
946 
947 /// EmitStoreThroughLValue - Store the specified rvalue into the specified
948 /// lvalue, where both are guaranteed to the have the same type, and that type
949 /// is 'Ty'.
950 void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst) {
951   if (!Dst.isSimple()) {
952     if (Dst.isVectorElt()) {
953       // Read/modify/write the vector, inserting the new element.
954       llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
955                                             Dst.isVolatileQualified());
956       Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
957                                         Dst.getVectorIdx(), "vecins");
958       Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
959       return;
960     }
961 
962     // If this is an update of extended vector elements, insert them as
963     // appropriate.
964     if (Dst.isExtVectorElt())
965       return EmitStoreThroughExtVectorComponentLValue(Src, Dst);
966 
967     assert(Dst.isBitField() && "Unknown LValue type");
968     return EmitStoreThroughBitfieldLValue(Src, Dst);
969   }
970 
971   // There's special magic for assigning into an ARC-qualified l-value.
972   if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) {
973     switch (Lifetime) {
974     case Qualifiers::OCL_None:
975       llvm_unreachable("present but none");
976 
977     case Qualifiers::OCL_ExplicitNone:
978       // nothing special
979       break;
980 
981     case Qualifiers::OCL_Strong:
982       EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
983       return;
984 
985     case Qualifiers::OCL_Weak:
986       EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
987       return;
988 
989     case Qualifiers::OCL_Autoreleasing:
990       Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(),
991                                                      Src.getScalarVal()));
992       // fall into the normal path
993       break;
994     }
995   }
996 
997   if (Dst.isObjCWeak() && !Dst.isNonGC()) {
998     // load of a __weak object.
999     llvm::Value *LvalueDst = Dst.getAddress();
1000     llvm::Value *src = Src.getScalarVal();
1001      CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
1002     return;
1003   }
1004 
1005   if (Dst.isObjCStrong() && !Dst.isNonGC()) {
1006     // load of a __strong object.
1007     llvm::Value *LvalueDst = Dst.getAddress();
1008     llvm::Value *src = Src.getScalarVal();
1009     if (Dst.isObjCIvar()) {
1010       assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
1011       llvm::Type *ResultType = ConvertType(getContext().LongTy);
1012       llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
1013       llvm::Value *dst = RHS;
1014       RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
1015       llvm::Value *LHS =
1016         Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
1017       llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
1018       CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
1019                                               BytesBetween);
1020     } else if (Dst.isGlobalObjCRef()) {
1021       CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
1022                                                 Dst.isThreadLocalRef());
1023     }
1024     else
1025       CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
1026     return;
1027   }
1028 
1029   assert(Src.isScalar() && "Can't emit an agg store with this method");
1030   EmitStoreOfScalar(Src.getScalarVal(), Dst);
1031 }
1032 
1033 void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
1034                                                      llvm::Value **Result) {
1035   const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
1036 
1037   // Get the output type.
1038   llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
1039   unsigned ResSizeInBits = CGM.getTargetData().getTypeSizeInBits(ResLTy);
1040 
1041   // Get the source value, truncated to the width of the bit-field.
1042   llvm::Value *SrcVal = Src.getScalarVal();
1043 
1044   if (Dst.getType()->isBooleanType())
1045     SrcVal = Builder.CreateIntCast(SrcVal, ResLTy, /*IsSigned=*/false);
1046 
1047   SrcVal = Builder.CreateAnd(SrcVal, llvm::APInt::getLowBitsSet(ResSizeInBits,
1048                                                                 Info.getSize()),
1049                              "bf.value");
1050 
1051   // Return the new value of the bit-field, if requested.
1052   if (Result) {
1053     // Cast back to the proper type for result.
1054     llvm::Type *SrcTy = Src.getScalarVal()->getType();
1055     llvm::Value *ReloadVal = Builder.CreateIntCast(SrcVal, SrcTy, false,
1056                                                    "bf.reload.val");
1057 
1058     // Sign extend if necessary.
1059     if (Info.isSigned()) {
1060       unsigned ExtraBits = ResSizeInBits - Info.getSize();
1061       if (ExtraBits)
1062         ReloadVal = Builder.CreateAShr(Builder.CreateShl(ReloadVal, ExtraBits),
1063                                        ExtraBits, "bf.reload.sext");
1064     }
1065 
1066     *Result = ReloadVal;
1067   }
1068 
1069   // Iterate over the components, writing each piece to memory.
1070   for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) {
1071     const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i);
1072 
1073     // Get the field pointer.
1074     llvm::Value *Ptr = Dst.getBitFieldBaseAddr();
1075     unsigned addressSpace =
1076       cast<llvm::PointerType>(Ptr->getType())->getAddressSpace();
1077 
1078     // Only offset by the field index if used, so that incoming values are not
1079     // required to be structures.
1080     if (AI.FieldIndex)
1081       Ptr = Builder.CreateStructGEP(Ptr, AI.FieldIndex, "bf.field");
1082 
1083     // Offset by the byte offset, if used.
1084     if (!AI.FieldByteOffset.isZero()) {
1085       Ptr = EmitCastToVoidPtr(Ptr);
1086       Ptr = Builder.CreateConstGEP1_32(Ptr, AI.FieldByteOffset.getQuantity(),
1087                                        "bf.field.offs");
1088     }
1089 
1090     // Cast to the access type.
1091     llvm::Type *AccessLTy =
1092       llvm::Type::getIntNTy(getLLVMContext(), AI.AccessWidth);
1093 
1094     llvm::Type *PTy = AccessLTy->getPointerTo(addressSpace);
1095     Ptr = Builder.CreateBitCast(Ptr, PTy);
1096 
1097     // Extract the piece of the bit-field value to write in this access, limited
1098     // to the values that are part of this access.
1099     llvm::Value *Val = SrcVal;
1100     if (AI.TargetBitOffset)
1101       Val = Builder.CreateLShr(Val, AI.TargetBitOffset);
1102     Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(ResSizeInBits,
1103                                                             AI.TargetBitWidth));
1104 
1105     // Extend or truncate to the access size.
1106     if (ResSizeInBits < AI.AccessWidth)
1107       Val = Builder.CreateZExt(Val, AccessLTy);
1108     else if (ResSizeInBits > AI.AccessWidth)
1109       Val = Builder.CreateTrunc(Val, AccessLTy);
1110 
1111     // Shift into the position in memory.
1112     if (AI.FieldBitStart)
1113       Val = Builder.CreateShl(Val, AI.FieldBitStart);
1114 
1115     // If necessary, load and OR in bits that are outside of the bit-field.
1116     if (AI.TargetBitWidth != AI.AccessWidth) {
1117       llvm::LoadInst *Load = Builder.CreateLoad(Ptr, Dst.isVolatileQualified());
1118       if (!AI.AccessAlignment.isZero())
1119         Load->setAlignment(AI.AccessAlignment.getQuantity());
1120 
1121       // Compute the mask for zeroing the bits that are part of the bit-field.
1122       llvm::APInt InvMask =
1123         ~llvm::APInt::getBitsSet(AI.AccessWidth, AI.FieldBitStart,
1124                                  AI.FieldBitStart + AI.TargetBitWidth);
1125 
1126       // Apply the mask and OR in to the value to write.
1127       Val = Builder.CreateOr(Builder.CreateAnd(Load, InvMask), Val);
1128     }
1129 
1130     // Write the value.
1131     llvm::StoreInst *Store = Builder.CreateStore(Val, Ptr,
1132                                                  Dst.isVolatileQualified());
1133     if (!AI.AccessAlignment.isZero())
1134       Store->setAlignment(AI.AccessAlignment.getQuantity());
1135   }
1136 }
1137 
1138 void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
1139                                                                LValue Dst) {
1140   // This access turns into a read/modify/write of the vector.  Load the input
1141   // value now.
1142   llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
1143                                         Dst.isVolatileQualified());
1144   const llvm::Constant *Elts = Dst.getExtVectorElts();
1145 
1146   llvm::Value *SrcVal = Src.getScalarVal();
1147 
1148   if (const VectorType *VTy = Dst.getType()->getAs<VectorType>()) {
1149     unsigned NumSrcElts = VTy->getNumElements();
1150     unsigned NumDstElts =
1151        cast<llvm::VectorType>(Vec->getType())->getNumElements();
1152     if (NumDstElts == NumSrcElts) {
1153       // Use shuffle vector is the src and destination are the same number of
1154       // elements and restore the vector mask since it is on the side it will be
1155       // stored.
1156       SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
1157       for (unsigned i = 0; i != NumSrcElts; ++i) {
1158         unsigned InIdx = getAccessedFieldNo(i, Elts);
1159         Mask[InIdx] = llvm::ConstantInt::get(Int32Ty, i);
1160       }
1161 
1162       llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1163       Vec = Builder.CreateShuffleVector(SrcVal,
1164                                         llvm::UndefValue::get(Vec->getType()),
1165                                         MaskV);
1166     } else if (NumDstElts > NumSrcElts) {
1167       // Extended the source vector to the same length and then shuffle it
1168       // into the destination.
1169       // FIXME: since we're shuffling with undef, can we just use the indices
1170       //        into that?  This could be simpler.
1171       SmallVector<llvm::Constant*, 4> ExtMask;
1172       unsigned i;
1173       for (i = 0; i != NumSrcElts; ++i)
1174         ExtMask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1175       for (; i != NumDstElts; ++i)
1176         ExtMask.push_back(llvm::UndefValue::get(Int32Ty));
1177       llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
1178       llvm::Value *ExtSrcVal =
1179         Builder.CreateShuffleVector(SrcVal,
1180                                     llvm::UndefValue::get(SrcVal->getType()),
1181                                     ExtMaskV);
1182       // build identity
1183       SmallVector<llvm::Constant*, 4> Mask;
1184       for (unsigned i = 0; i != NumDstElts; ++i)
1185         Mask.push_back(llvm::ConstantInt::get(Int32Ty, i));
1186 
1187       // modify when what gets shuffled in
1188       for (unsigned i = 0; i != NumSrcElts; ++i) {
1189         unsigned Idx = getAccessedFieldNo(i, Elts);
1190         Mask[Idx] = llvm::ConstantInt::get(Int32Ty, i+NumDstElts);
1191       }
1192       llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1193       Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV);
1194     } else {
1195       // We should never shorten the vector
1196       llvm_unreachable("unexpected shorten vector length");
1197     }
1198   } else {
1199     // If the Src is a scalar (not a vector) it must be updating one element.
1200     unsigned InIdx = getAccessedFieldNo(0, Elts);
1201     llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1202     Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt);
1203   }
1204 
1205   Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
1206 }
1207 
1208 // setObjCGCLValueClass - sets class of he lvalue for the purpose of
1209 // generating write-barries API. It is currently a global, ivar,
1210 // or neither.
1211 static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1212                                  LValue &LV,
1213                                  bool IsMemberAccess=false) {
1214   if (Ctx.getLangOptions().getGC() == LangOptions::NonGC)
1215     return;
1216 
1217   if (isa<ObjCIvarRefExpr>(E)) {
1218     QualType ExpTy = E->getType();
1219     if (IsMemberAccess && ExpTy->isPointerType()) {
1220       // If ivar is a structure pointer, assigning to field of
1221       // this struct follows gcc's behavior and makes it a non-ivar
1222       // writer-barrier conservatively.
1223       ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1224       if (ExpTy->isRecordType()) {
1225         LV.setObjCIvar(false);
1226         return;
1227       }
1228     }
1229     LV.setObjCIvar(true);
1230     ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1231     LV.setBaseIvarExp(Exp->getBase());
1232     LV.setObjCArray(E->getType()->isArrayType());
1233     return;
1234   }
1235 
1236   if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1237     if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1238       if (VD->hasGlobalStorage()) {
1239         LV.setGlobalObjCRef(true);
1240         LV.setThreadLocalRef(VD->isThreadSpecified());
1241       }
1242     }
1243     LV.setObjCArray(E->getType()->isArrayType());
1244     return;
1245   }
1246 
1247   if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1248     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1249     return;
1250   }
1251 
1252   if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1253     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1254     if (LV.isObjCIvar()) {
1255       // If cast is to a structure pointer, follow gcc's behavior and make it
1256       // a non-ivar write-barrier.
1257       QualType ExpTy = E->getType();
1258       if (ExpTy->isPointerType())
1259         ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1260       if (ExpTy->isRecordType())
1261         LV.setObjCIvar(false);
1262     }
1263     return;
1264   }
1265 
1266   if (const GenericSelectionExpr *Exp = dyn_cast<GenericSelectionExpr>(E)) {
1267     setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
1268     return;
1269   }
1270 
1271   if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1272     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1273     return;
1274   }
1275 
1276   if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1277     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1278     return;
1279   }
1280 
1281   if (const ObjCBridgedCastExpr *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
1282     setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1283     return;
1284   }
1285 
1286   if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1287     setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1288     if (LV.isObjCIvar() && !LV.isObjCArray())
1289       // Using array syntax to assigning to what an ivar points to is not
1290       // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1291       LV.setObjCIvar(false);
1292     else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1293       // Using array syntax to assigning to what global points to is not
1294       // same as assigning to the global itself. {id *G;} G[i] = 0;
1295       LV.setGlobalObjCRef(false);
1296     return;
1297   }
1298 
1299   if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1300     setObjCGCLValueClass(Ctx, Exp->getBase(), LV, true);
1301     // We don't know if member is an 'ivar', but this flag is looked at
1302     // only in the context of LV.isObjCIvar().
1303     LV.setObjCArray(E->getType()->isArrayType());
1304     return;
1305   }
1306 }
1307 
1308 static llvm::Value *
1309 EmitBitCastOfLValueToProperType(CodeGenFunction &CGF,
1310                                 llvm::Value *V, llvm::Type *IRType,
1311                                 StringRef Name = StringRef()) {
1312   unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
1313   return CGF.Builder.CreateBitCast(V, IRType->getPointerTo(AS), Name);
1314 }
1315 
1316 static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1317                                       const Expr *E, const VarDecl *VD) {
1318   assert((VD->hasExternalStorage() || VD->isFileVarDecl()) &&
1319          "Var decl must have external storage or be a file var decl!");
1320 
1321   llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1322   llvm::Type *RealVarTy = CGF.getTypes().ConvertTypeForMem(VD->getType());
1323   V = EmitBitCastOfLValueToProperType(CGF, V, RealVarTy);
1324   unsigned Alignment = CGF.getContext().getDeclAlign(VD).getQuantity();
1325   QualType T = E->getType();
1326   LValue LV;
1327   if (VD->getType()->isReferenceType()) {
1328     llvm::LoadInst *LI = CGF.Builder.CreateLoad(V);
1329     LI->setAlignment(Alignment);
1330     V = LI;
1331     LV = CGF.MakeNaturalAlignAddrLValue(V, T);
1332   } else {
1333     LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1334   }
1335   setObjCGCLValueClass(CGF.getContext(), E, LV);
1336   return LV;
1337 }
1338 
1339 static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1340                                      const Expr *E, const FunctionDecl *FD) {
1341   llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1342   if (!FD->hasPrototype()) {
1343     if (const FunctionProtoType *Proto =
1344             FD->getType()->getAs<FunctionProtoType>()) {
1345       // Ugly case: for a K&R-style definition, the type of the definition
1346       // isn't the same as the type of a use.  Correct for this with a
1347       // bitcast.
1348       QualType NoProtoType =
1349           CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1350       NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1351       V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType));
1352     }
1353   }
1354   unsigned Alignment = CGF.getContext().getDeclAlign(FD).getQuantity();
1355   return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1356 }
1357 
1358 LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1359   const NamedDecl *ND = E->getDecl();
1360   unsigned Alignment = getContext().getDeclAlign(ND).getQuantity();
1361   QualType T = E->getType();
1362 
1363   if (ND->hasAttr<WeakRefAttr>()) {
1364     const ValueDecl *VD = cast<ValueDecl>(ND);
1365     llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1366     return MakeAddrLValue(Aliasee, E->getType(), Alignment);
1367   }
1368 
1369   if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1370 
1371     // Check if this is a global variable.
1372     if (VD->hasExternalStorage() || VD->isFileVarDecl())
1373       return EmitGlobalVarDeclLValue(*this, E, VD);
1374 
1375     bool NonGCable = VD->hasLocalStorage() &&
1376                      !VD->getType()->isReferenceType() &&
1377                      !VD->hasAttr<BlocksAttr>();
1378 
1379     llvm::Value *V = LocalDeclMap[VD];
1380     if (!V && VD->isStaticLocal())
1381       V = CGM.getStaticLocalDeclAddress(VD);
1382     assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1383 
1384     if (VD->hasAttr<BlocksAttr>())
1385       V = BuildBlockByrefAddress(V, VD);
1386 
1387     LValue LV;
1388     if (VD->getType()->isReferenceType()) {
1389       llvm::LoadInst *LI = Builder.CreateLoad(V);
1390       LI->setAlignment(Alignment);
1391       V = LI;
1392       LV = MakeNaturalAlignAddrLValue(V, T);
1393     } else {
1394       LV = MakeAddrLValue(V, T, Alignment);
1395     }
1396 
1397     if (NonGCable) {
1398       LV.getQuals().removeObjCGCAttr();
1399       LV.setNonGC(true);
1400     }
1401     setObjCGCLValueClass(getContext(), E, LV);
1402     return LV;
1403   }
1404 
1405   if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
1406     return EmitFunctionDeclLValue(*this, E, fn);
1407 
1408   llvm_unreachable("Unhandled DeclRefExpr");
1409 
1410   // an invalid LValue, but the assert will
1411   // ensure that this point is never reached.
1412   return LValue();
1413 }
1414 
1415 LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
1416   unsigned Alignment =
1417     getContext().getDeclAlign(E->getDecl()).getQuantity();
1418   return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
1419 }
1420 
1421 LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1422   // __extension__ doesn't affect lvalue-ness.
1423   if (E->getOpcode() == UO_Extension)
1424     return EmitLValue(E->getSubExpr());
1425 
1426   QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1427   switch (E->getOpcode()) {
1428   default: llvm_unreachable("Unknown unary operator lvalue!");
1429   case UO_Deref: {
1430     QualType T = E->getSubExpr()->getType()->getPointeeType();
1431     assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1432 
1433     LValue LV = MakeAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1434     LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1435 
1436     // We should not generate __weak write barrier on indirect reference
1437     // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1438     // But, we continue to generate __strong write barrier on indirect write
1439     // into a pointer to object.
1440     if (getContext().getLangOptions().ObjC1 &&
1441         getContext().getLangOptions().getGC() != LangOptions::NonGC &&
1442         LV.isObjCWeak())
1443       LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1444     return LV;
1445   }
1446   case UO_Real:
1447   case UO_Imag: {
1448     LValue LV = EmitLValue(E->getSubExpr());
1449     assert(LV.isSimple() && "real/imag on non-ordinary l-value");
1450     llvm::Value *Addr = LV.getAddress();
1451 
1452     // real and imag are valid on scalars.  This is a faster way of
1453     // testing that.
1454     if (!cast<llvm::PointerType>(Addr->getType())
1455            ->getElementType()->isStructTy()) {
1456       assert(E->getSubExpr()->getType()->isArithmeticType());
1457       return LV;
1458     }
1459 
1460     assert(E->getSubExpr()->getType()->isAnyComplexType());
1461 
1462     unsigned Idx = E->getOpcode() == UO_Imag;
1463     return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1464                                                   Idx, "idx"),
1465                           ExprTy);
1466   }
1467   case UO_PreInc:
1468   case UO_PreDec: {
1469     LValue LV = EmitLValue(E->getSubExpr());
1470     bool isInc = E->getOpcode() == UO_PreInc;
1471 
1472     if (E->getType()->isAnyComplexType())
1473       EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1474     else
1475       EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1476     return LV;
1477   }
1478   }
1479 }
1480 
1481 LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1482   return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1483                         E->getType());
1484 }
1485 
1486 LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1487   return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1488                         E->getType());
1489 }
1490 
1491 
1492 LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1493   switch (E->getIdentType()) {
1494   default:
1495     return EmitUnsupportedLValue(E, "predefined expression");
1496 
1497   case PredefinedExpr::Func:
1498   case PredefinedExpr::Function:
1499   case PredefinedExpr::PrettyFunction: {
1500     unsigned Type = E->getIdentType();
1501     std::string GlobalVarName;
1502 
1503     switch (Type) {
1504     default: llvm_unreachable("Invalid type");
1505     case PredefinedExpr::Func:
1506       GlobalVarName = "__func__.";
1507       break;
1508     case PredefinedExpr::Function:
1509       GlobalVarName = "__FUNCTION__.";
1510       break;
1511     case PredefinedExpr::PrettyFunction:
1512       GlobalVarName = "__PRETTY_FUNCTION__.";
1513       break;
1514     }
1515 
1516     StringRef FnName = CurFn->getName();
1517     if (FnName.startswith("\01"))
1518       FnName = FnName.substr(1);
1519     GlobalVarName += FnName;
1520 
1521     const Decl *CurDecl = CurCodeDecl;
1522     if (CurDecl == 0)
1523       CurDecl = getContext().getTranslationUnitDecl();
1524 
1525     std::string FunctionName =
1526         (isa<BlockDecl>(CurDecl)
1527          ? FnName.str()
1528          : PredefinedExpr::ComputeName((PredefinedExpr::IdentType)Type, CurDecl));
1529 
1530     llvm::Constant *C =
1531       CGM.GetAddrOfConstantCString(FunctionName, GlobalVarName.c_str());
1532     return MakeAddrLValue(C, E->getType());
1533   }
1534   }
1535 }
1536 
1537 llvm::BasicBlock *CodeGenFunction::getTrapBB() {
1538   const CodeGenOptions &GCO = CGM.getCodeGenOpts();
1539 
1540   // If we are not optimzing, don't collapse all calls to trap in the function
1541   // to the same call, that way, in the debugger they can see which operation
1542   // did in fact fail.  If we are optimizing, we collapse all calls to trap down
1543   // to just one per function to save on codesize.
1544   if (GCO.OptimizationLevel && TrapBB)
1545     return TrapBB;
1546 
1547   llvm::BasicBlock *Cont = 0;
1548   if (HaveInsertPoint()) {
1549     Cont = createBasicBlock("cont");
1550     EmitBranch(Cont);
1551   }
1552   TrapBB = createBasicBlock("trap");
1553   EmitBlock(TrapBB);
1554 
1555   llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap);
1556   llvm::CallInst *TrapCall = Builder.CreateCall(F);
1557   TrapCall->setDoesNotReturn();
1558   TrapCall->setDoesNotThrow();
1559   Builder.CreateUnreachable();
1560 
1561   if (Cont)
1562     EmitBlock(Cont);
1563   return TrapBB;
1564 }
1565 
1566 /// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
1567 /// array to pointer, return the array subexpression.
1568 static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
1569   // If this isn't just an array->pointer decay, bail out.
1570   const CastExpr *CE = dyn_cast<CastExpr>(E);
1571   if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
1572     return 0;
1573 
1574   // If this is a decay from variable width array, bail out.
1575   const Expr *SubExpr = CE->getSubExpr();
1576   if (SubExpr->getType()->isVariableArrayType())
1577     return 0;
1578 
1579   return SubExpr;
1580 }
1581 
1582 LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
1583   // The index must always be an integer, which is not an aggregate.  Emit it.
1584   llvm::Value *Idx = EmitScalarExpr(E->getIdx());
1585   QualType IdxTy  = E->getIdx()->getType();
1586   bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
1587 
1588   // If the base is a vector type, then we are forming a vector element lvalue
1589   // with this subscript.
1590   if (E->getBase()->getType()->isVectorType()) {
1591     // Emit the vector as an lvalue to get its address.
1592     LValue LHS = EmitLValue(E->getBase());
1593     assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
1594     Idx = Builder.CreateIntCast(Idx, Int32Ty, IdxSigned, "vidx");
1595     return LValue::MakeVectorElt(LHS.getAddress(), Idx,
1596                                  E->getBase()->getType());
1597   }
1598 
1599   // Extend or truncate the index type to 32 or 64-bits.
1600   if (Idx->getType() != IntPtrTy)
1601     Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
1602 
1603   // FIXME: As llvm implements the object size checking, this can come out.
1604   if (CatchUndefined) {
1605     if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E->getBase())){
1606       if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1607         if (ICE->getCastKind() == CK_ArrayToPointerDecay) {
1608           if (const ConstantArrayType *CAT
1609               = getContext().getAsConstantArrayType(DRE->getType())) {
1610             llvm::APInt Size = CAT->getSize();
1611             llvm::BasicBlock *Cont = createBasicBlock("cont");
1612             Builder.CreateCondBr(Builder.CreateICmpULE(Idx,
1613                                   llvm::ConstantInt::get(Idx->getType(), Size)),
1614                                  Cont, getTrapBB());
1615             EmitBlock(Cont);
1616           }
1617         }
1618       }
1619     }
1620   }
1621 
1622   // We know that the pointer points to a type of the correct size, unless the
1623   // size is a VLA or Objective-C interface.
1624   llvm::Value *Address = 0;
1625   unsigned ArrayAlignment = 0;
1626   if (const VariableArrayType *vla =
1627         getContext().getAsVariableArrayType(E->getType())) {
1628     // The base must be a pointer, which is not an aggregate.  Emit
1629     // it.  It needs to be emitted first in case it's what captures
1630     // the VLA bounds.
1631     Address = EmitScalarExpr(E->getBase());
1632 
1633     // The element count here is the total number of non-VLA elements.
1634     llvm::Value *numElements = getVLASize(vla).first;
1635 
1636     // Effectively, the multiply by the VLA size is part of the GEP.
1637     // GEP indexes are signed, and scaling an index isn't permitted to
1638     // signed-overflow, so we use the same semantics for our explicit
1639     // multiply.  We suppress this if overflow is not undefined behavior.
1640     if (getLangOptions().isSignedOverflowDefined()) {
1641       Idx = Builder.CreateMul(Idx, numElements);
1642       Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1643     } else {
1644       Idx = Builder.CreateNSWMul(Idx, numElements);
1645       Address = Builder.CreateInBoundsGEP(Address, Idx, "arrayidx");
1646     }
1647   } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
1648     // Indexing over an interface, as in "NSString *P; P[4];"
1649     llvm::Value *InterfaceSize =
1650       llvm::ConstantInt::get(Idx->getType(),
1651           getContext().getTypeSizeInChars(OIT).getQuantity());
1652 
1653     Idx = Builder.CreateMul(Idx, InterfaceSize);
1654 
1655     // The base must be a pointer, which is not an aggregate.  Emit it.
1656     llvm::Value *Base = EmitScalarExpr(E->getBase());
1657     Address = EmitCastToVoidPtr(Base);
1658     Address = Builder.CreateGEP(Address, Idx, "arrayidx");
1659     Address = Builder.CreateBitCast(Address, Base->getType());
1660   } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
1661     // If this is A[i] where A is an array, the frontend will have decayed the
1662     // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
1663     // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
1664     // "gep x, i" here.  Emit one "gep A, 0, i".
1665     assert(Array->getType()->isArrayType() &&
1666            "Array to pointer decay must have array source type!");
1667     LValue ArrayLV = EmitLValue(Array);
1668     llvm::Value *ArrayPtr = ArrayLV.getAddress();
1669     llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
1670     llvm::Value *Args[] = { Zero, Idx };
1671 
1672     // Propagate the alignment from the array itself to the result.
1673     ArrayAlignment = ArrayLV.getAlignment();
1674 
1675     if (getContext().getLangOptions().isSignedOverflowDefined())
1676       Address = Builder.CreateGEP(ArrayPtr, Args, "arrayidx");
1677     else
1678       Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, "arrayidx");
1679   } else {
1680     // The base must be a pointer, which is not an aggregate.  Emit it.
1681     llvm::Value *Base = EmitScalarExpr(E->getBase());
1682     if (getContext().getLangOptions().isSignedOverflowDefined())
1683       Address = Builder.CreateGEP(Base, Idx, "arrayidx");
1684     else
1685       Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
1686   }
1687 
1688   QualType T = E->getBase()->getType()->getPointeeType();
1689   assert(!T.isNull() &&
1690          "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
1691 
1692   // Limit the alignment to that of the result type.
1693   if (ArrayAlignment) {
1694     unsigned Align = getContext().getTypeAlignInChars(T).getQuantity();
1695     ArrayAlignment = std::min(Align, ArrayAlignment);
1696   }
1697 
1698   LValue LV = MakeAddrLValue(Address, T, ArrayAlignment);
1699   LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
1700 
1701   if (getContext().getLangOptions().ObjC1 &&
1702       getContext().getLangOptions().getGC() != LangOptions::NonGC) {
1703     LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1704     setObjCGCLValueClass(getContext(), E, LV);
1705   }
1706   return LV;
1707 }
1708 
1709 static
1710 llvm::Constant *GenerateConstantVector(llvm::LLVMContext &VMContext,
1711                                        SmallVector<unsigned, 4> &Elts) {
1712   SmallVector<llvm::Constant*, 4> CElts;
1713 
1714   llvm::Type *Int32Ty = llvm::Type::getInt32Ty(VMContext);
1715   for (unsigned i = 0, e = Elts.size(); i != e; ++i)
1716     CElts.push_back(llvm::ConstantInt::get(Int32Ty, Elts[i]));
1717 
1718   return llvm::ConstantVector::get(CElts);
1719 }
1720 
1721 LValue CodeGenFunction::
1722 EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
1723   // Emit the base vector as an l-value.
1724   LValue Base;
1725 
1726   // ExtVectorElementExpr's base can either be a vector or pointer to vector.
1727   if (E->isArrow()) {
1728     // If it is a pointer to a vector, emit the address and form an lvalue with
1729     // it.
1730     llvm::Value *Ptr = EmitScalarExpr(E->getBase());
1731     const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
1732     Base = MakeAddrLValue(Ptr, PT->getPointeeType());
1733     Base.getQuals().removeObjCGCAttr();
1734   } else if (E->getBase()->isGLValue()) {
1735     // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
1736     // emit the base as an lvalue.
1737     assert(E->getBase()->getType()->isVectorType());
1738     Base = EmitLValue(E->getBase());
1739   } else {
1740     // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
1741     assert(E->getBase()->getType()->isVectorType() &&
1742            "Result must be a vector");
1743     llvm::Value *Vec = EmitScalarExpr(E->getBase());
1744 
1745     // Store the vector to memory (because LValue wants an address).
1746     llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
1747     Builder.CreateStore(Vec, VecMem);
1748     Base = MakeAddrLValue(VecMem, E->getBase()->getType());
1749   }
1750 
1751   QualType type =
1752     E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers());
1753 
1754   // Encode the element access list into a vector of unsigned indices.
1755   SmallVector<unsigned, 4> Indices;
1756   E->getEncodedElementAccess(Indices);
1757 
1758   if (Base.isSimple()) {
1759     llvm::Constant *CV = GenerateConstantVector(getLLVMContext(), Indices);
1760     return LValue::MakeExtVectorElt(Base.getAddress(), CV, type);
1761   }
1762   assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
1763 
1764   llvm::Constant *BaseElts = Base.getExtVectorElts();
1765   SmallVector<llvm::Constant *, 4> CElts;
1766 
1767   for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
1768     if (isa<llvm::ConstantAggregateZero>(BaseElts))
1769       CElts.push_back(llvm::ConstantInt::get(Int32Ty, 0));
1770     else
1771       CElts.push_back(cast<llvm::Constant>(BaseElts->getOperand(Indices[i])));
1772   }
1773   llvm::Constant *CV = llvm::ConstantVector::get(CElts);
1774   return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV, type);
1775 }
1776 
1777 LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
1778   bool isNonGC = false;
1779   Expr *BaseExpr = E->getBase();
1780   llvm::Value *BaseValue = NULL;
1781   Qualifiers BaseQuals;
1782 
1783   // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
1784   if (E->isArrow()) {
1785     BaseValue = EmitScalarExpr(BaseExpr);
1786     const PointerType *PTy =
1787       BaseExpr->getType()->getAs<PointerType>();
1788     BaseQuals = PTy->getPointeeType().getQualifiers();
1789   } else {
1790     LValue BaseLV = EmitLValue(BaseExpr);
1791     if (BaseLV.isNonGC())
1792       isNonGC = true;
1793     // FIXME: this isn't right for bitfields.
1794     BaseValue = BaseLV.getAddress();
1795     QualType BaseTy = BaseExpr->getType();
1796     BaseQuals = BaseTy.getQualifiers();
1797   }
1798 
1799   NamedDecl *ND = E->getMemberDecl();
1800   if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
1801     LValue LV = EmitLValueForField(BaseValue, Field,
1802                                    BaseQuals.getCVRQualifiers());
1803     LV.setNonGC(isNonGC);
1804     setObjCGCLValueClass(getContext(), E, LV);
1805     return LV;
1806   }
1807 
1808   if (VarDecl *VD = dyn_cast<VarDecl>(ND))
1809     return EmitGlobalVarDeclLValue(*this, E, VD);
1810 
1811   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
1812     return EmitFunctionDeclLValue(*this, E, FD);
1813 
1814   llvm_unreachable("Unhandled member declaration!");
1815 }
1816 
1817 LValue CodeGenFunction::EmitLValueForBitfield(llvm::Value *BaseValue,
1818                                               const FieldDecl *Field,
1819                                               unsigned CVRQualifiers) {
1820   const CGRecordLayout &RL =
1821     CGM.getTypes().getCGRecordLayout(Field->getParent());
1822   const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
1823   return LValue::MakeBitfield(BaseValue, Info,
1824                           Field->getType().withCVRQualifiers(CVRQualifiers));
1825 }
1826 
1827 /// EmitLValueForAnonRecordField - Given that the field is a member of
1828 /// an anonymous struct or union buried inside a record, and given
1829 /// that the base value is a pointer to the enclosing record, derive
1830 /// an lvalue for the ultimate field.
1831 LValue CodeGenFunction::EmitLValueForAnonRecordField(llvm::Value *BaseValue,
1832                                              const IndirectFieldDecl *Field,
1833                                                      unsigned CVRQualifiers) {
1834   IndirectFieldDecl::chain_iterator I = Field->chain_begin(),
1835     IEnd = Field->chain_end();
1836   while (true) {
1837     LValue LV = EmitLValueForField(BaseValue, cast<FieldDecl>(*I),
1838                                    CVRQualifiers);
1839     if (++I == IEnd) return LV;
1840 
1841     assert(LV.isSimple());
1842     BaseValue = LV.getAddress();
1843     CVRQualifiers |= LV.getVRQualifiers();
1844   }
1845 }
1846 
1847 LValue CodeGenFunction::EmitLValueForField(llvm::Value *baseAddr,
1848                                            const FieldDecl *field,
1849                                            unsigned cvr) {
1850   if (field->isBitField())
1851     return EmitLValueForBitfield(baseAddr, field, cvr);
1852 
1853   const RecordDecl *rec = field->getParent();
1854   QualType type = field->getType();
1855   unsigned alignment = getContext().getDeclAlign(field).getQuantity();
1856 
1857   bool mayAlias = rec->hasAttr<MayAliasAttr>();
1858 
1859   llvm::Value *addr = baseAddr;
1860   if (rec->isUnion()) {
1861     // For unions, there is no pointer adjustment.
1862     assert(!type->isReferenceType() && "union has reference member");
1863   } else {
1864     // For structs, we GEP to the field that the record layout suggests.
1865     unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
1866     addr = Builder.CreateStructGEP(addr, idx, field->getName());
1867 
1868     // If this is a reference field, load the reference right now.
1869     if (const ReferenceType *refType = type->getAs<ReferenceType>()) {
1870       llvm::LoadInst *load = Builder.CreateLoad(addr, "ref");
1871       if (cvr & Qualifiers::Volatile) load->setVolatile(true);
1872       load->setAlignment(alignment);
1873 
1874       if (CGM.shouldUseTBAA()) {
1875         llvm::MDNode *tbaa;
1876         if (mayAlias)
1877           tbaa = CGM.getTBAAInfo(getContext().CharTy);
1878         else
1879           tbaa = CGM.getTBAAInfo(type);
1880         CGM.DecorateInstruction(load, tbaa);
1881       }
1882 
1883       addr = load;
1884       mayAlias = false;
1885       type = refType->getPointeeType();
1886       if (type->isIncompleteType())
1887         alignment = 0;
1888       else
1889         alignment = getContext().getTypeAlignInChars(type).getQuantity();
1890       cvr = 0; // qualifiers don't recursively apply to referencee
1891     }
1892   }
1893 
1894   // Make sure that the address is pointing to the right type.  This is critical
1895   // for both unions and structs.  A union needs a bitcast, a struct element
1896   // will need a bitcast if the LLVM type laid out doesn't match the desired
1897   // type.
1898   addr = EmitBitCastOfLValueToProperType(*this, addr,
1899                                          CGM.getTypes().ConvertTypeForMem(type),
1900                                          field->getName());
1901 
1902   if (field->hasAttr<AnnotateAttr>())
1903     addr = EmitFieldAnnotations(field, addr);
1904 
1905   LValue LV = MakeAddrLValue(addr, type, alignment);
1906   LV.getQuals().addCVRQualifiers(cvr);
1907 
1908   // __weak attribute on a field is ignored.
1909   if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
1910     LV.getQuals().removeObjCGCAttr();
1911 
1912   // Fields of may_alias structs act like 'char' for TBAA purposes.
1913   // FIXME: this should get propagated down through anonymous structs
1914   // and unions.
1915   if (mayAlias && LV.getTBAAInfo())
1916     LV.setTBAAInfo(CGM.getTBAAInfo(getContext().CharTy));
1917 
1918   return LV;
1919 }
1920 
1921 LValue
1922 CodeGenFunction::EmitLValueForFieldInitialization(llvm::Value *BaseValue,
1923                                                   const FieldDecl *Field,
1924                                                   unsigned CVRQualifiers) {
1925   QualType FieldType = Field->getType();
1926 
1927   if (!FieldType->isReferenceType())
1928     return EmitLValueForField(BaseValue, Field, CVRQualifiers);
1929 
1930   const CGRecordLayout &RL =
1931     CGM.getTypes().getCGRecordLayout(Field->getParent());
1932   unsigned idx = RL.getLLVMFieldNo(Field);
1933   llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx);
1934   assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
1935 
1936 
1937   // Make sure that the address is pointing to the right type.  This is critical
1938   // for both unions and structs.  A union needs a bitcast, a struct element
1939   // will need a bitcast if the LLVM type laid out doesn't match the desired
1940   // type.
1941   llvm::Type *llvmType = ConvertTypeForMem(FieldType);
1942   unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
1943   V = Builder.CreateBitCast(V, llvmType->getPointerTo(AS));
1944 
1945   unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
1946   return MakeAddrLValue(V, FieldType, Alignment);
1947 }
1948 
1949 LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
1950   llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
1951   const Expr *InitExpr = E->getInitializer();
1952   LValue Result = MakeAddrLValue(DeclPtr, E->getType());
1953 
1954   EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
1955                    /*Init*/ true);
1956 
1957   return Result;
1958 }
1959 
1960 LValue CodeGenFunction::
1961 EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
1962   if (!expr->isGLValue()) {
1963     // ?: here should be an aggregate.
1964     assert((hasAggregateLLVMType(expr->getType()) &&
1965             !expr->getType()->isAnyComplexType()) &&
1966            "Unexpected conditional operator!");
1967     return EmitAggExprToLValue(expr);
1968   }
1969 
1970   const Expr *condExpr = expr->getCond();
1971   bool CondExprBool;
1972   if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
1973     const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr();
1974     if (!CondExprBool) std::swap(live, dead);
1975 
1976     if (!ContainsLabel(dead))
1977       return EmitLValue(live);
1978   }
1979 
1980   OpaqueValueMapping binding(*this, expr);
1981 
1982   llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
1983   llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
1984   llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
1985 
1986   ConditionalEvaluation eval(*this);
1987   EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock);
1988 
1989   // Any temporaries created here are conditional.
1990   EmitBlock(lhsBlock);
1991   eval.begin(*this);
1992   LValue lhs = EmitLValue(expr->getTrueExpr());
1993   eval.end(*this);
1994 
1995   if (!lhs.isSimple())
1996     return EmitUnsupportedLValue(expr, "conditional operator");
1997 
1998   lhsBlock = Builder.GetInsertBlock();
1999   Builder.CreateBr(contBlock);
2000 
2001   // Any temporaries created here are conditional.
2002   EmitBlock(rhsBlock);
2003   eval.begin(*this);
2004   LValue rhs = EmitLValue(expr->getFalseExpr());
2005   eval.end(*this);
2006   if (!rhs.isSimple())
2007     return EmitUnsupportedLValue(expr, "conditional operator");
2008   rhsBlock = Builder.GetInsertBlock();
2009 
2010   EmitBlock(contBlock);
2011 
2012   llvm::PHINode *phi = Builder.CreatePHI(lhs.getAddress()->getType(), 2,
2013                                          "cond-lvalue");
2014   phi->addIncoming(lhs.getAddress(), lhsBlock);
2015   phi->addIncoming(rhs.getAddress(), rhsBlock);
2016   return MakeAddrLValue(phi, expr->getType());
2017 }
2018 
2019 /// EmitCastLValue - Casts are never lvalues unless that cast is a dynamic_cast.
2020 /// If the cast is a dynamic_cast, we can have the usual lvalue result,
2021 /// otherwise if a cast is needed by the code generator in an lvalue context,
2022 /// then it must mean that we need the address of an aggregate in order to
2023 /// access one of its fields.  This can happen for all the reasons that casts
2024 /// are permitted with aggregate result, including noop aggregate casts, and
2025 /// cast from scalar to union.
2026 LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
2027   switch (E->getCastKind()) {
2028   case CK_ToVoid:
2029     return EmitUnsupportedLValue(E, "unexpected cast lvalue");
2030 
2031   case CK_Dependent:
2032     llvm_unreachable("dependent cast kind in IR gen!");
2033 
2034   case CK_NoOp:
2035   case CK_LValueToRValue:
2036     if (!E->getSubExpr()->Classify(getContext()).isPRValue()
2037         || E->getType()->isRecordType())
2038       return EmitLValue(E->getSubExpr());
2039     // Fall through to synthesize a temporary.
2040 
2041   case CK_BitCast:
2042   case CK_ArrayToPointerDecay:
2043   case CK_FunctionToPointerDecay:
2044   case CK_NullToMemberPointer:
2045   case CK_NullToPointer:
2046   case CK_IntegralToPointer:
2047   case CK_PointerToIntegral:
2048   case CK_PointerToBoolean:
2049   case CK_VectorSplat:
2050   case CK_IntegralCast:
2051   case CK_IntegralToBoolean:
2052   case CK_IntegralToFloating:
2053   case CK_FloatingToIntegral:
2054   case CK_FloatingToBoolean:
2055   case CK_FloatingCast:
2056   case CK_FloatingRealToComplex:
2057   case CK_FloatingComplexToReal:
2058   case CK_FloatingComplexToBoolean:
2059   case CK_FloatingComplexCast:
2060   case CK_FloatingComplexToIntegralComplex:
2061   case CK_IntegralRealToComplex:
2062   case CK_IntegralComplexToReal:
2063   case CK_IntegralComplexToBoolean:
2064   case CK_IntegralComplexCast:
2065   case CK_IntegralComplexToFloatingComplex:
2066   case CK_DerivedToBaseMemberPointer:
2067   case CK_BaseToDerivedMemberPointer:
2068   case CK_MemberPointerToBoolean:
2069   case CK_AnyPointerToBlockPointerCast:
2070   case CK_ARCProduceObject:
2071   case CK_ARCConsumeObject:
2072   case CK_ARCReclaimReturnedObject:
2073   case CK_ARCExtendBlockObject: {
2074     // These casts only produce lvalues when we're binding a reference to a
2075     // temporary realized from a (converted) pure rvalue. Emit the expression
2076     // as a value, copy it into a temporary, and return an lvalue referring to
2077     // that temporary.
2078     llvm::Value *V = CreateMemTemp(E->getType(), "ref.temp");
2079     EmitAnyExprToMem(E, V, E->getType().getQualifiers(), false);
2080     return MakeAddrLValue(V, E->getType());
2081   }
2082 
2083   case CK_Dynamic: {
2084     LValue LV = EmitLValue(E->getSubExpr());
2085     llvm::Value *V = LV.getAddress();
2086     const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
2087     return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
2088   }
2089 
2090   case CK_ConstructorConversion:
2091   case CK_UserDefinedConversion:
2092   case CK_CPointerToObjCPointerCast:
2093   case CK_BlockPointerToObjCPointerCast:
2094     return EmitLValue(E->getSubExpr());
2095 
2096   case CK_UncheckedDerivedToBase:
2097   case CK_DerivedToBase: {
2098     const RecordType *DerivedClassTy =
2099       E->getSubExpr()->getType()->getAs<RecordType>();
2100     CXXRecordDecl *DerivedClassDecl =
2101       cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2102 
2103     LValue LV = EmitLValue(E->getSubExpr());
2104     llvm::Value *This = LV.getAddress();
2105 
2106     // Perform the derived-to-base conversion
2107     llvm::Value *Base =
2108       GetAddressOfBaseClass(This, DerivedClassDecl,
2109                             E->path_begin(), E->path_end(),
2110                             /*NullCheckValue=*/false);
2111 
2112     return MakeAddrLValue(Base, E->getType());
2113   }
2114   case CK_ToUnion:
2115     return EmitAggExprToLValue(E);
2116   case CK_BaseToDerived: {
2117     const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
2118     CXXRecordDecl *DerivedClassDecl =
2119       cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2120 
2121     LValue LV = EmitLValue(E->getSubExpr());
2122 
2123     // Perform the base-to-derived conversion
2124     llvm::Value *Derived =
2125       GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
2126                                E->path_begin(), E->path_end(),
2127                                /*NullCheckValue=*/false);
2128 
2129     return MakeAddrLValue(Derived, E->getType());
2130   }
2131   case CK_LValueBitCast: {
2132     // This must be a reinterpret_cast (or c-style equivalent).
2133     const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
2134 
2135     LValue LV = EmitLValue(E->getSubExpr());
2136     llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2137                                            ConvertType(CE->getTypeAsWritten()));
2138     return MakeAddrLValue(V, E->getType());
2139   }
2140   case CK_ObjCObjectLValueCast: {
2141     LValue LV = EmitLValue(E->getSubExpr());
2142     QualType ToType = getContext().getLValueReferenceType(E->getType());
2143     llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2144                                            ConvertType(ToType));
2145     return MakeAddrLValue(V, E->getType());
2146   }
2147   }
2148 
2149   llvm_unreachable("Unhandled lvalue cast kind?");
2150 }
2151 
2152 LValue CodeGenFunction::EmitNullInitializationLValue(
2153                                               const CXXScalarValueInitExpr *E) {
2154   QualType Ty = E->getType();
2155   LValue LV = MakeAddrLValue(CreateMemTemp(Ty), Ty);
2156   EmitNullInitialization(LV.getAddress(), Ty);
2157   return LV;
2158 }
2159 
2160 LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
2161   assert(OpaqueValueMappingData::shouldBindAsLValue(e));
2162   return getOpaqueLValueMapping(e);
2163 }
2164 
2165 LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
2166                                            const MaterializeTemporaryExpr *E) {
2167   RValue RV = EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0);
2168   return MakeAddrLValue(RV.getScalarVal(), E->getType());
2169 }
2170 
2171 
2172 //===--------------------------------------------------------------------===//
2173 //                             Expression Emission
2174 //===--------------------------------------------------------------------===//
2175 
2176 RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
2177                                      ReturnValueSlot ReturnValue) {
2178   if (CGDebugInfo *DI = getDebugInfo())
2179     DI->EmitLocation(Builder, E->getLocStart());
2180 
2181   // Builtins never have block type.
2182   if (E->getCallee()->getType()->isBlockPointerType())
2183     return EmitBlockCallExpr(E, ReturnValue);
2184 
2185   if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
2186     return EmitCXXMemberCallExpr(CE, ReturnValue);
2187 
2188   if (const CUDAKernelCallExpr *CE = dyn_cast<CUDAKernelCallExpr>(E))
2189     return EmitCUDAKernelCallExpr(CE, ReturnValue);
2190 
2191   const Decl *TargetDecl = E->getCalleeDecl();
2192   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl)) {
2193     if (unsigned builtinID = FD->getBuiltinID())
2194       return EmitBuiltinExpr(FD, builtinID, E);
2195   }
2196 
2197   if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
2198     if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
2199       return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
2200 
2201   if (const CXXPseudoDestructorExpr *PseudoDtor
2202           = dyn_cast<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
2203     QualType DestroyedType = PseudoDtor->getDestroyedType();
2204     if (getContext().getLangOptions().ObjCAutoRefCount &&
2205         DestroyedType->isObjCLifetimeType() &&
2206         (DestroyedType.getObjCLifetime() == Qualifiers::OCL_Strong ||
2207          DestroyedType.getObjCLifetime() == Qualifiers::OCL_Weak)) {
2208       // Automatic Reference Counting:
2209       //   If the pseudo-expression names a retainable object with weak or
2210       //   strong lifetime, the object shall be released.
2211       Expr *BaseExpr = PseudoDtor->getBase();
2212       llvm::Value *BaseValue = NULL;
2213       Qualifiers BaseQuals;
2214 
2215       // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
2216       if (PseudoDtor->isArrow()) {
2217         BaseValue = EmitScalarExpr(BaseExpr);
2218         const PointerType *PTy = BaseExpr->getType()->getAs<PointerType>();
2219         BaseQuals = PTy->getPointeeType().getQualifiers();
2220       } else {
2221         LValue BaseLV = EmitLValue(BaseExpr);
2222         BaseValue = BaseLV.getAddress();
2223         QualType BaseTy = BaseExpr->getType();
2224         BaseQuals = BaseTy.getQualifiers();
2225       }
2226 
2227       switch (PseudoDtor->getDestroyedType().getObjCLifetime()) {
2228       case Qualifiers::OCL_None:
2229       case Qualifiers::OCL_ExplicitNone:
2230       case Qualifiers::OCL_Autoreleasing:
2231         break;
2232 
2233       case Qualifiers::OCL_Strong:
2234         EmitARCRelease(Builder.CreateLoad(BaseValue,
2235                           PseudoDtor->getDestroyedType().isVolatileQualified()),
2236                        /*precise*/ true);
2237         break;
2238 
2239       case Qualifiers::OCL_Weak:
2240         EmitARCDestroyWeak(BaseValue);
2241         break;
2242       }
2243     } else {
2244       // C++ [expr.pseudo]p1:
2245       //   The result shall only be used as the operand for the function call
2246       //   operator (), and the result of such a call has type void. The only
2247       //   effect is the evaluation of the postfix-expression before the dot or
2248       //   arrow.
2249       EmitScalarExpr(E->getCallee());
2250     }
2251 
2252     return RValue::get(0);
2253   }
2254 
2255   llvm::Value *Callee = EmitScalarExpr(E->getCallee());
2256   return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
2257                   E->arg_begin(), E->arg_end(), TargetDecl);
2258 }
2259 
2260 LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
2261   // Comma expressions just emit their LHS then their RHS as an l-value.
2262   if (E->getOpcode() == BO_Comma) {
2263     EmitIgnoredExpr(E->getLHS());
2264     EnsureInsertPoint();
2265     return EmitLValue(E->getRHS());
2266   }
2267 
2268   if (E->getOpcode() == BO_PtrMemD ||
2269       E->getOpcode() == BO_PtrMemI)
2270     return EmitPointerToDataMemberBinaryExpr(E);
2271 
2272   assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
2273 
2274   // Note that in all of these cases, __block variables need the RHS
2275   // evaluated first just in case the variable gets moved by the RHS.
2276 
2277   if (!hasAggregateLLVMType(E->getType())) {
2278     switch (E->getLHS()->getType().getObjCLifetime()) {
2279     case Qualifiers::OCL_Strong:
2280       return EmitARCStoreStrong(E, /*ignored*/ false).first;
2281 
2282     case Qualifiers::OCL_Autoreleasing:
2283       return EmitARCStoreAutoreleasing(E).first;
2284 
2285     // No reason to do any of these differently.
2286     case Qualifiers::OCL_None:
2287     case Qualifiers::OCL_ExplicitNone:
2288     case Qualifiers::OCL_Weak:
2289       break;
2290     }
2291 
2292     RValue RV = EmitAnyExpr(E->getRHS());
2293     LValue LV = EmitLValue(E->getLHS());
2294     EmitStoreThroughLValue(RV, LV);
2295     return LV;
2296   }
2297 
2298   if (E->getType()->isAnyComplexType())
2299     return EmitComplexAssignmentLValue(E);
2300 
2301   return EmitAggExprToLValue(E);
2302 }
2303 
2304 LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
2305   RValue RV = EmitCallExpr(E);
2306 
2307   if (!RV.isScalar())
2308     return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2309 
2310   assert(E->getCallReturnType()->isReferenceType() &&
2311          "Can't have a scalar return unless the return type is a "
2312          "reference type!");
2313 
2314   return MakeAddrLValue(RV.getScalarVal(), E->getType());
2315 }
2316 
2317 LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
2318   // FIXME: This shouldn't require another copy.
2319   return EmitAggExprToLValue(E);
2320 }
2321 
2322 LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
2323   assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
2324          && "binding l-value to type which needs a temporary");
2325   AggValueSlot Slot = CreateAggTemp(E->getType());
2326   EmitCXXConstructExpr(E, Slot);
2327   return MakeAddrLValue(Slot.getAddr(), E->getType());
2328 }
2329 
2330 LValue
2331 CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
2332   return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
2333 }
2334 
2335 LValue
2336 CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
2337   AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
2338   Slot.setExternallyDestructed();
2339   EmitAggExpr(E->getSubExpr(), Slot);
2340   EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
2341   return MakeAddrLValue(Slot.getAddr(), E->getType());
2342 }
2343 
2344 LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
2345   RValue RV = EmitObjCMessageExpr(E);
2346 
2347   if (!RV.isScalar())
2348     return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2349 
2350   assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
2351          "Can't have a scalar return unless the return type is a "
2352          "reference type!");
2353 
2354   return MakeAddrLValue(RV.getScalarVal(), E->getType());
2355 }
2356 
2357 LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
2358   llvm::Value *V =
2359     CGM.getObjCRuntime().GetSelector(Builder, E->getSelector(), true);
2360   return MakeAddrLValue(V, E->getType());
2361 }
2362 
2363 llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
2364                                              const ObjCIvarDecl *Ivar) {
2365   return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
2366 }
2367 
2368 LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
2369                                           llvm::Value *BaseValue,
2370                                           const ObjCIvarDecl *Ivar,
2371                                           unsigned CVRQualifiers) {
2372   return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
2373                                                    Ivar, CVRQualifiers);
2374 }
2375 
2376 LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
2377   // FIXME: A lot of the code below could be shared with EmitMemberExpr.
2378   llvm::Value *BaseValue = 0;
2379   const Expr *BaseExpr = E->getBase();
2380   Qualifiers BaseQuals;
2381   QualType ObjectTy;
2382   if (E->isArrow()) {
2383     BaseValue = EmitScalarExpr(BaseExpr);
2384     ObjectTy = BaseExpr->getType()->getPointeeType();
2385     BaseQuals = ObjectTy.getQualifiers();
2386   } else {
2387     LValue BaseLV = EmitLValue(BaseExpr);
2388     // FIXME: this isn't right for bitfields.
2389     BaseValue = BaseLV.getAddress();
2390     ObjectTy = BaseExpr->getType();
2391     BaseQuals = ObjectTy.getQualifiers();
2392   }
2393 
2394   LValue LV =
2395     EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
2396                       BaseQuals.getCVRQualifiers());
2397   setObjCGCLValueClass(getContext(), E, LV);
2398   return LV;
2399 }
2400 
2401 LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
2402   // Can only get l-value for message expression returning aggregate type
2403   RValue RV = EmitAnyExprToTemp(E);
2404   return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2405 }
2406 
2407 RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
2408                                  ReturnValueSlot ReturnValue,
2409                                  CallExpr::const_arg_iterator ArgBeg,
2410                                  CallExpr::const_arg_iterator ArgEnd,
2411                                  const Decl *TargetDecl) {
2412   // Get the actual function type. The callee type will always be a pointer to
2413   // function type or a block pointer type.
2414   assert(CalleeType->isFunctionPointerType() &&
2415          "Call must have function pointer type!");
2416 
2417   CalleeType = getContext().getCanonicalType(CalleeType);
2418 
2419   const FunctionType *FnType
2420     = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
2421 
2422   CallArgList Args;
2423   EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd);
2424 
2425   const CGFunctionInfo &FnInfo = CGM.getTypes().getFunctionInfo(Args, FnType);
2426 
2427   // C99 6.5.2.2p6:
2428   //   If the expression that denotes the called function has a type
2429   //   that does not include a prototype, [the default argument
2430   //   promotions are performed]. If the number of arguments does not
2431   //   equal the number of parameters, the behavior is undefined. If
2432   //   the function is defined with a type that includes a prototype,
2433   //   and either the prototype ends with an ellipsis (, ...) or the
2434   //   types of the arguments after promotion are not compatible with
2435   //   the types of the parameters, the behavior is undefined. If the
2436   //   function is defined with a type that does not include a
2437   //   prototype, and the types of the arguments after promotion are
2438   //   not compatible with those of the parameters after promotion,
2439   //   the behavior is undefined [except in some trivial cases].
2440   // That is, in the general case, we should assume that a call
2441   // through an unprototyped function type works like a *non-variadic*
2442   // call.  The way we make this work is to cast to the exact type
2443   // of the promoted arguments.
2444   if (isa<FunctionNoProtoType>(FnType) &&
2445       !getTargetHooks().isNoProtoCallVariadic(FnType->getCallConv())) {
2446     assert(cast<llvm::FunctionType>(Callee->getType()->getContainedType(0))
2447              ->isVarArg());
2448     llvm::Type *CalleeTy = getTypes().GetFunctionType(FnInfo, false);
2449     CalleeTy = CalleeTy->getPointerTo();
2450     Callee = Builder.CreateBitCast(Callee, CalleeTy, "callee.knr.cast");
2451   }
2452 
2453   return EmitCall(FnInfo, Callee, ReturnValue, Args, TargetDecl);
2454 }
2455 
2456 LValue CodeGenFunction::
2457 EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
2458   llvm::Value *BaseV;
2459   if (E->getOpcode() == BO_PtrMemI)
2460     BaseV = EmitScalarExpr(E->getLHS());
2461   else
2462     BaseV = EmitLValue(E->getLHS()).getAddress();
2463 
2464   llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
2465 
2466   const MemberPointerType *MPT
2467     = E->getRHS()->getType()->getAs<MemberPointerType>();
2468 
2469   llvm::Value *AddV =
2470     CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
2471 
2472   return MakeAddrLValue(AddV, MPT->getPointeeType());
2473 }
2474 
2475 static void
2476 EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, llvm::Value *Dest,
2477              llvm::Value *Ptr, llvm::Value *Val1, llvm::Value *Val2,
2478              uint64_t Size, unsigned Align, llvm::AtomicOrdering Order) {
2479   if (E->isCmpXChg()) {
2480     // Note that cmpxchg only supports specifying one ordering and
2481     // doesn't support weak cmpxchg, at least at the moment.
2482     llvm::LoadInst *LoadVal1 = CGF.Builder.CreateLoad(Val1);
2483     LoadVal1->setAlignment(Align);
2484     llvm::LoadInst *LoadVal2 = CGF.Builder.CreateLoad(Val2);
2485     LoadVal2->setAlignment(Align);
2486     llvm::AtomicCmpXchgInst *CXI =
2487         CGF.Builder.CreateAtomicCmpXchg(Ptr, LoadVal1, LoadVal2, Order);
2488     CXI->setVolatile(E->isVolatile());
2489     llvm::StoreInst *StoreVal1 = CGF.Builder.CreateStore(CXI, Val1);
2490     StoreVal1->setAlignment(Align);
2491     llvm::Value *Cmp = CGF.Builder.CreateICmpEQ(CXI, LoadVal1);
2492     CGF.EmitStoreOfScalar(Cmp, CGF.MakeAddrLValue(Dest, E->getType()));
2493     return;
2494   }
2495 
2496   if (E->getOp() == AtomicExpr::Load) {
2497     llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr);
2498     Load->setAtomic(Order);
2499     Load->setAlignment(Size);
2500     Load->setVolatile(E->isVolatile());
2501     llvm::StoreInst *StoreDest = CGF.Builder.CreateStore(Load, Dest);
2502     StoreDest->setAlignment(Align);
2503     return;
2504   }
2505 
2506   if (E->getOp() == AtomicExpr::Store) {
2507     assert(!Dest && "Store does not return a value");
2508     llvm::LoadInst *LoadVal1 = CGF.Builder.CreateLoad(Val1);
2509     LoadVal1->setAlignment(Align);
2510     llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr);
2511     Store->setAtomic(Order);
2512     Store->setAlignment(Size);
2513     Store->setVolatile(E->isVolatile());
2514     return;
2515   }
2516 
2517   llvm::AtomicRMWInst::BinOp Op = llvm::AtomicRMWInst::Add;
2518   switch (E->getOp()) {
2519     case AtomicExpr::CmpXchgWeak:
2520     case AtomicExpr::CmpXchgStrong:
2521     case AtomicExpr::Store:
2522     case AtomicExpr::Load:  assert(0 && "Already handled!");
2523     case AtomicExpr::Add:   Op = llvm::AtomicRMWInst::Add;  break;
2524     case AtomicExpr::Sub:   Op = llvm::AtomicRMWInst::Sub;  break;
2525     case AtomicExpr::And:   Op = llvm::AtomicRMWInst::And;  break;
2526     case AtomicExpr::Or:    Op = llvm::AtomicRMWInst::Or;   break;
2527     case AtomicExpr::Xor:   Op = llvm::AtomicRMWInst::Xor;  break;
2528     case AtomicExpr::Xchg:  Op = llvm::AtomicRMWInst::Xchg; break;
2529   }
2530   llvm::LoadInst *LoadVal1 = CGF.Builder.CreateLoad(Val1);
2531   LoadVal1->setAlignment(Align);
2532   llvm::AtomicRMWInst *RMWI =
2533       CGF.Builder.CreateAtomicRMW(Op, Ptr, LoadVal1, Order);
2534   RMWI->setVolatile(E->isVolatile());
2535   llvm::StoreInst *StoreDest = CGF.Builder.CreateStore(RMWI, Dest);
2536   StoreDest->setAlignment(Align);
2537 }
2538 
2539 // This function emits any expression (scalar, complex, or aggregate)
2540 // into a temporary alloca.
2541 static llvm::Value *
2542 EmitValToTemp(CodeGenFunction &CGF, Expr *E) {
2543   llvm::Value *DeclPtr = CGF.CreateMemTemp(E->getType(), ".atomictmp");
2544   CGF.EmitAnyExprToMem(E, DeclPtr, E->getType().getQualifiers(),
2545                        /*Init*/ true);
2546   return DeclPtr;
2547 }
2548 
2549 static RValue ConvertTempToRValue(CodeGenFunction &CGF, QualType Ty,
2550                                   llvm::Value *Dest) {
2551   if (Ty->isAnyComplexType())
2552     return RValue::getComplex(CGF.LoadComplexFromAddr(Dest, false));
2553   if (CGF.hasAggregateLLVMType(Ty))
2554     return RValue::getAggregate(Dest);
2555   return RValue::get(CGF.EmitLoadOfScalar(CGF.MakeAddrLValue(Dest, Ty)));
2556 }
2557 
2558 RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E, llvm::Value *Dest) {
2559   QualType AtomicTy = E->getPtr()->getType()->getPointeeType();
2560   QualType MemTy = AtomicTy->getAs<AtomicType>()->getValueType();
2561   CharUnits sizeChars = getContext().getTypeSizeInChars(AtomicTy);
2562   uint64_t Size = sizeChars.getQuantity();
2563   CharUnits alignChars = getContext().getTypeAlignInChars(AtomicTy);
2564   unsigned Align = alignChars.getQuantity();
2565   unsigned MaxInlineWidth =
2566       getContext().getTargetInfo().getMaxAtomicInlineWidth();
2567   bool UseLibcall = (Size != Align || Size > MaxInlineWidth);
2568 
2569   llvm::Value *Ptr, *Order, *OrderFail = 0, *Val1 = 0, *Val2 = 0;
2570   Ptr = EmitScalarExpr(E->getPtr());
2571   Order = EmitScalarExpr(E->getOrder());
2572   if (E->isCmpXChg()) {
2573     Val1 = EmitScalarExpr(E->getVal1());
2574     Val2 = EmitValToTemp(*this, E->getVal2());
2575     OrderFail = EmitScalarExpr(E->getOrderFail());
2576     (void)OrderFail; // OrderFail is unused at the moment
2577   } else if ((E->getOp() == AtomicExpr::Add || E->getOp() == AtomicExpr::Sub) &&
2578              MemTy->isPointerType()) {
2579     // For pointers, we're required to do a bit of math: adding 1 to an int*
2580     // is not the same as adding 1 to a uintptr_t.
2581     QualType Val1Ty = E->getVal1()->getType();
2582     llvm::Value *Val1Scalar = EmitScalarExpr(E->getVal1());
2583     CharUnits PointeeIncAmt =
2584         getContext().getTypeSizeInChars(MemTy->getPointeeType());
2585     Val1Scalar = Builder.CreateMul(Val1Scalar, CGM.getSize(PointeeIncAmt));
2586     Val1 = CreateMemTemp(Val1Ty, ".atomictmp");
2587     EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Val1, Val1Ty));
2588   } else if (E->getOp() != AtomicExpr::Load) {
2589     Val1 = EmitValToTemp(*this, E->getVal1());
2590   }
2591 
2592   if (E->getOp() != AtomicExpr::Store && !Dest)
2593     Dest = CreateMemTemp(E->getType(), ".atomicdst");
2594 
2595   if (UseLibcall) {
2596     // FIXME: Finalize what the libcalls are actually supposed to look like.
2597     // See also http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary .
2598     return EmitUnsupportedRValue(E, "atomic library call");
2599   }
2600 #if 0
2601   if (UseLibcall) {
2602     const char* LibCallName;
2603     switch (E->getOp()) {
2604     case AtomicExpr::CmpXchgWeak:
2605       LibCallName = "__atomic_compare_exchange_generic"; break;
2606     case AtomicExpr::CmpXchgStrong:
2607       LibCallName = "__atomic_compare_exchange_generic"; break;
2608     case AtomicExpr::Add:   LibCallName = "__atomic_fetch_add_generic"; break;
2609     case AtomicExpr::Sub:   LibCallName = "__atomic_fetch_sub_generic"; break;
2610     case AtomicExpr::And:   LibCallName = "__atomic_fetch_and_generic"; break;
2611     case AtomicExpr::Or:    LibCallName = "__atomic_fetch_or_generic"; break;
2612     case AtomicExpr::Xor:   LibCallName = "__atomic_fetch_xor_generic"; break;
2613     case AtomicExpr::Xchg:  LibCallName = "__atomic_exchange_generic"; break;
2614     case AtomicExpr::Store: LibCallName = "__atomic_store_generic"; break;
2615     case AtomicExpr::Load:  LibCallName = "__atomic_load_generic"; break;
2616     }
2617     llvm::SmallVector<QualType, 4> Params;
2618     CallArgList Args;
2619     QualType RetTy = getContext().VoidTy;
2620     if (E->getOp() != AtomicExpr::Store && !E->isCmpXChg())
2621       Args.add(RValue::get(EmitCastToVoidPtr(Dest)),
2622                getContext().VoidPtrTy);
2623     Args.add(RValue::get(EmitCastToVoidPtr(Ptr)),
2624              getContext().VoidPtrTy);
2625     if (E->getOp() != AtomicExpr::Load)
2626       Args.add(RValue::get(EmitCastToVoidPtr(Val1)),
2627                getContext().VoidPtrTy);
2628     if (E->isCmpXChg()) {
2629       Args.add(RValue::get(EmitCastToVoidPtr(Val2)),
2630                getContext().VoidPtrTy);
2631       RetTy = getContext().IntTy;
2632     }
2633     Args.add(RValue::get(llvm::ConstantInt::get(SizeTy, Size)),
2634              getContext().getSizeType());
2635     const CGFunctionInfo &FuncInfo =
2636         CGM.getTypes().getFunctionInfo(RetTy, Args, FunctionType::ExtInfo());
2637     llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FuncInfo, false);
2638     llvm::Constant *Func = CGM.CreateRuntimeFunction(FTy, LibCallName);
2639     RValue Res = EmitCall(FuncInfo, Func, ReturnValueSlot(), Args);
2640     if (E->isCmpXChg())
2641       return Res;
2642     if (E->getOp() == AtomicExpr::Store)
2643       return RValue::get(0);
2644     return ConvertTempToRValue(*this, E->getType(), Dest);
2645   }
2646 #endif
2647   llvm::Type *IPtrTy =
2648       llvm::IntegerType::get(getLLVMContext(), Size * 8)->getPointerTo();
2649   llvm::Value *OrigDest = Dest;
2650   Ptr = Builder.CreateBitCast(Ptr, IPtrTy);
2651   if (Val1) Val1 = Builder.CreateBitCast(Val1, IPtrTy);
2652   if (Val2) Val2 = Builder.CreateBitCast(Val2, IPtrTy);
2653   if (Dest && !E->isCmpXChg()) Dest = Builder.CreateBitCast(Dest, IPtrTy);
2654 
2655   if (isa<llvm::ConstantInt>(Order)) {
2656     int ord = cast<llvm::ConstantInt>(Order)->getZExtValue();
2657     switch (ord) {
2658     case 0:  // memory_order_relaxed
2659       EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2660                    llvm::Monotonic);
2661       break;
2662     case 1:  // memory_order_consume
2663     case 2:  // memory_order_acquire
2664       EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2665                    llvm::Acquire);
2666       break;
2667     case 3:  // memory_order_release
2668       EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2669                    llvm::Release);
2670       break;
2671     case 4:  // memory_order_acq_rel
2672       EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2673                    llvm::AcquireRelease);
2674       break;
2675     case 5:  // memory_order_seq_cst
2676       EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2677                    llvm::SequentiallyConsistent);
2678       break;
2679     default: // invalid order
2680       // We should not ever get here normally, but it's hard to
2681       // enforce that in general.
2682       break;
2683     }
2684     if (E->getOp() == AtomicExpr::Store)
2685       return RValue::get(0);
2686     return ConvertTempToRValue(*this, E->getType(), OrigDest);
2687   }
2688 
2689   // Long case, when Order isn't obviously constant.
2690 
2691   // Create all the relevant BB's
2692   llvm::BasicBlock *MonotonicBB = 0, *AcquireBB = 0, *ReleaseBB = 0,
2693                    *AcqRelBB = 0, *SeqCstBB = 0;
2694   MonotonicBB = createBasicBlock("monotonic", CurFn);
2695   if (E->getOp() != AtomicExpr::Store)
2696     AcquireBB = createBasicBlock("acquire", CurFn);
2697   if (E->getOp() != AtomicExpr::Load)
2698     ReleaseBB = createBasicBlock("release", CurFn);
2699   if (E->getOp() != AtomicExpr::Load && E->getOp() != AtomicExpr::Store)
2700     AcqRelBB = createBasicBlock("acqrel", CurFn);
2701   SeqCstBB = createBasicBlock("seqcst", CurFn);
2702   llvm::BasicBlock *ContBB = createBasicBlock("atomic.continue", CurFn);
2703 
2704   // Create the switch for the split
2705   // MonotonicBB is arbitrarily chosen as the default case; in practice, this
2706   // doesn't matter unless someone is crazy enough to use something that
2707   // doesn't fold to a constant for the ordering.
2708   Order = Builder.CreateIntCast(Order, Builder.getInt32Ty(), false);
2709   llvm::SwitchInst *SI = Builder.CreateSwitch(Order, MonotonicBB);
2710 
2711   // Emit all the different atomics
2712   Builder.SetInsertPoint(MonotonicBB);
2713   EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2714                llvm::Monotonic);
2715   Builder.CreateBr(ContBB);
2716   if (E->getOp() != AtomicExpr::Store) {
2717     Builder.SetInsertPoint(AcquireBB);
2718     EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2719                  llvm::Acquire);
2720     Builder.CreateBr(ContBB);
2721     SI->addCase(Builder.getInt32(1), AcquireBB);
2722     SI->addCase(Builder.getInt32(2), AcquireBB);
2723   }
2724   if (E->getOp() != AtomicExpr::Load) {
2725     Builder.SetInsertPoint(ReleaseBB);
2726     EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2727                  llvm::Release);
2728     Builder.CreateBr(ContBB);
2729     SI->addCase(Builder.getInt32(3), ReleaseBB);
2730   }
2731   if (E->getOp() != AtomicExpr::Load && E->getOp() != AtomicExpr::Store) {
2732     Builder.SetInsertPoint(AcqRelBB);
2733     EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2734                  llvm::AcquireRelease);
2735     Builder.CreateBr(ContBB);
2736     SI->addCase(Builder.getInt32(4), AcqRelBB);
2737   }
2738   Builder.SetInsertPoint(SeqCstBB);
2739   EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, Size, Align,
2740                llvm::SequentiallyConsistent);
2741   Builder.CreateBr(ContBB);
2742   SI->addCase(Builder.getInt32(5), SeqCstBB);
2743 
2744   // Cleanup and return
2745   Builder.SetInsertPoint(ContBB);
2746   if (E->getOp() == AtomicExpr::Store)
2747     return RValue::get(0);
2748   return ConvertTempToRValue(*this, E->getType(), OrigDest);
2749 }
2750 
2751 void CodeGenFunction::SetFPAccuracy(llvm::Value *Val, unsigned AccuracyN,
2752                                     unsigned AccuracyD) {
2753   assert(Val->getType()->isFPOrFPVectorTy());
2754   if (!AccuracyN || !isa<llvm::Instruction>(Val))
2755     return;
2756 
2757   llvm::Value *Vals[2];
2758   Vals[0] = llvm::ConstantInt::get(Int32Ty, AccuracyN);
2759   Vals[1] = llvm::ConstantInt::get(Int32Ty, AccuracyD);
2760   llvm::MDNode *Node = llvm::MDNode::get(getLLVMContext(), Vals);
2761 
2762   cast<llvm::Instruction>(Val)->setMetadata(llvm::LLVMContext::MD_fpaccuracy,
2763                                             Node);
2764 }
2765 
2766 namespace {
2767   struct LValueOrRValue {
2768     LValue LV;
2769     RValue RV;
2770   };
2771 }
2772 
2773 static LValueOrRValue emitPseudoObjectExpr(CodeGenFunction &CGF,
2774                                            const PseudoObjectExpr *E,
2775                                            bool forLValue,
2776                                            AggValueSlot slot) {
2777   llvm::SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
2778 
2779   // Find the result expression, if any.
2780   const Expr *resultExpr = E->getResultExpr();
2781   LValueOrRValue result;
2782 
2783   for (PseudoObjectExpr::const_semantics_iterator
2784          i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
2785     const Expr *semantic = *i;
2786 
2787     // If this semantic expression is an opaque value, bind it
2788     // to the result of its source expression.
2789     if (const OpaqueValueExpr *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
2790 
2791       // If this is the result expression, we may need to evaluate
2792       // directly into the slot.
2793       typedef CodeGenFunction::OpaqueValueMappingData OVMA;
2794       OVMA opaqueData;
2795       if (ov == resultExpr && ov->isRValue() && !forLValue &&
2796           CodeGenFunction::hasAggregateLLVMType(ov->getType()) &&
2797           !ov->getType()->isAnyComplexType()) {
2798         CGF.EmitAggExpr(ov->getSourceExpr(), slot);
2799 
2800         LValue LV = CGF.MakeAddrLValue(slot.getAddr(), ov->getType());
2801         opaqueData = OVMA::bind(CGF, ov, LV);
2802         result.RV = slot.asRValue();
2803 
2804       // Otherwise, emit as normal.
2805       } else {
2806         opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
2807 
2808         // If this is the result, also evaluate the result now.
2809         if (ov == resultExpr) {
2810           if (forLValue)
2811             result.LV = CGF.EmitLValue(ov);
2812           else
2813             result.RV = CGF.EmitAnyExpr(ov, slot);
2814         }
2815       }
2816 
2817       opaques.push_back(opaqueData);
2818 
2819     // Otherwise, if the expression is the result, evaluate it
2820     // and remember the result.
2821     } else if (semantic == resultExpr) {
2822       if (forLValue)
2823         result.LV = CGF.EmitLValue(semantic);
2824       else
2825         result.RV = CGF.EmitAnyExpr(semantic, slot);
2826 
2827     // Otherwise, evaluate the expression in an ignored context.
2828     } else {
2829       CGF.EmitIgnoredExpr(semantic);
2830     }
2831   }
2832 
2833   // Unbind all the opaques now.
2834   for (unsigned i = 0, e = opaques.size(); i != e; ++i)
2835     opaques[i].unbind(CGF);
2836 
2837   return result;
2838 }
2839 
2840 RValue CodeGenFunction::EmitPseudoObjectRValue(const PseudoObjectExpr *E,
2841                                                AggValueSlot slot) {
2842   return emitPseudoObjectExpr(*this, E, false, slot).RV;
2843 }
2844 
2845 LValue CodeGenFunction::EmitPseudoObjectLValue(const PseudoObjectExpr *E) {
2846   return emitPseudoObjectExpr(*this, E, true, AggValueSlot::ignored()).LV;
2847 }
2848