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 "CGCXXABI.h"
16#include "CGCall.h"
17#include "CGDebugInfo.h"
18#include "CGObjCRuntime.h"
19#include "CGRecordLayout.h"
20#include "CodeGenModule.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/ADT/Hashing.h"
26#include "llvm/IR/DataLayout.h"
27#include "llvm/IR/Intrinsics.h"
28#include "llvm/IR/LLVMContext.h"
29#include "llvm/IR/MDBuilder.h"
30#include "llvm/Support/ConvertUTF.h"
31
32using namespace clang;
33using namespace CodeGen;
34
35//===--------------------------------------------------------------------===//
36//                        Miscellaneous Helper Methods
37//===--------------------------------------------------------------------===//
38
39llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
40  unsigned addressSpace =
41    cast<llvm::PointerType>(value->getType())->getAddressSpace();
42
43  llvm::PointerType *destType = Int8PtrTy;
44  if (addressSpace)
45    destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
46
47  if (value->getType() == destType) return value;
48  return Builder.CreateBitCast(value, destType);
49}
50
51/// CreateTempAlloca - This creates a alloca and inserts it into the entry
52/// block.
53llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
54                                                    const Twine &Name) {
55  if (!Builder.isNamePreserving())
56    return new llvm::AllocaInst(Ty, 0, "", AllocaInsertPt);
57  return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
58}
59
60void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
61                                     llvm::Value *Init) {
62  llvm::StoreInst *Store = new llvm::StoreInst(Init, Var);
63  llvm::BasicBlock *Block = AllocaInsertPt->getParent();
64  Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
65}
66
67llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
68                                                const Twine &Name) {
69  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
70  // FIXME: Should we prefer the preferred type alignment here?
71  CharUnits Align = getContext().getTypeAlignInChars(Ty);
72  Alloc->setAlignment(Align.getQuantity());
73  return Alloc;
74}
75
76llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
77                                                 const Twine &Name) {
78  llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
79  // FIXME: Should we prefer the preferred type alignment here?
80  CharUnits Align = getContext().getTypeAlignInChars(Ty);
81  Alloc->setAlignment(Align.getQuantity());
82  return Alloc;
83}
84
85/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
86/// expression and compare the result against zero, returning an Int1Ty value.
87llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
88  if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
89    llvm::Value *MemPtr = EmitScalarExpr(E);
90    return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT);
91  }
92
93  QualType BoolTy = getContext().BoolTy;
94  if (!E->getType()->isAnyComplexType())
95    return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
96
97  return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
98}
99
100/// EmitIgnoredExpr - Emit code to compute the specified expression,
101/// ignoring the result.
102void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
103  if (E->isRValue())
104    return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
105
106  // Just emit it as an l-value and drop the result.
107  EmitLValue(E);
108}
109
110/// EmitAnyExpr - Emit code to compute the specified expression which
111/// can have any type.  The result is returned as an RValue struct.
112/// If this is an aggregate expression, AggSlot indicates where the
113/// result should be returned.
114RValue CodeGenFunction::EmitAnyExpr(const Expr *E,
115                                    AggValueSlot aggSlot,
116                                    bool ignoreResult) {
117  switch (getEvaluationKind(E->getType())) {
118  case TEK_Scalar:
119    return RValue::get(EmitScalarExpr(E, ignoreResult));
120  case TEK_Complex:
121    return RValue::getComplex(EmitComplexExpr(E, ignoreResult, ignoreResult));
122  case TEK_Aggregate:
123    if (!ignoreResult && aggSlot.isIgnored())
124      aggSlot = CreateAggTemp(E->getType(), "agg-temp");
125    EmitAggExpr(E, aggSlot);
126    return aggSlot.asRValue();
127  }
128  llvm_unreachable("bad evaluation kind");
129}
130
131/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
132/// always be accessible even if no aggregate location is provided.
133RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
134  AggValueSlot AggSlot = AggValueSlot::ignored();
135
136  if (hasAggregateEvaluationKind(E->getType()))
137    AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
138  return EmitAnyExpr(E, AggSlot);
139}
140
141/// EmitAnyExprToMem - Evaluate an expression into a given memory
142/// location.
143void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
144                                       llvm::Value *Location,
145                                       Qualifiers Quals,
146                                       bool IsInit) {
147  // FIXME: This function should take an LValue as an argument.
148  switch (getEvaluationKind(E->getType())) {
149  case TEK_Complex:
150    EmitComplexExprIntoLValue(E,
151                         MakeNaturalAlignAddrLValue(Location, E->getType()),
152                              /*isInit*/ false);
153    return;
154
155  case TEK_Aggregate: {
156    CharUnits Alignment = getContext().getTypeAlignInChars(E->getType());
157    EmitAggExpr(E, AggValueSlot::forAddr(Location, Alignment, Quals,
158                                         AggValueSlot::IsDestructed_t(IsInit),
159                                         AggValueSlot::DoesNotNeedGCBarriers,
160                                         AggValueSlot::IsAliased_t(!IsInit)));
161    return;
162  }
163
164  case TEK_Scalar: {
165    RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
166    LValue LV = MakeAddrLValue(Location, E->getType());
167    EmitStoreThroughLValue(RV, LV);
168    return;
169  }
170  }
171  llvm_unreachable("bad evaluation kind");
172}
173
174static void
175pushTemporaryCleanup(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M,
176                     const Expr *E, llvm::Value *ReferenceTemporary) {
177  // Objective-C++ ARC:
178  //   If we are binding a reference to a temporary that has ownership, we
179  //   need to perform retain/release operations on the temporary.
180  //
181  // FIXME: This should be looking at E, not M.
182  if (CGF.getLangOpts().ObjCAutoRefCount &&
183      M->getType()->isObjCLifetimeType()) {
184    QualType ObjCARCReferenceLifetimeType = M->getType();
185    switch (Qualifiers::ObjCLifetime Lifetime =
186                ObjCARCReferenceLifetimeType.getObjCLifetime()) {
187    case Qualifiers::OCL_None:
188    case Qualifiers::OCL_ExplicitNone:
189      // Carry on to normal cleanup handling.
190      break;
191
192    case Qualifiers::OCL_Autoreleasing:
193      // Nothing to do; cleaned up by an autorelease pool.
194      return;
195
196    case Qualifiers::OCL_Strong:
197    case Qualifiers::OCL_Weak:
198      switch (StorageDuration Duration = M->getStorageDuration()) {
199      case SD_Static:
200        // Note: we intentionally do not register a cleanup to release
201        // the object on program termination.
202        return;
203
204      case SD_Thread:
205        // FIXME: We should probably register a cleanup in this case.
206        return;
207
208      case SD_Automatic:
209      case SD_FullExpression:
210        assert(!ObjCARCReferenceLifetimeType->isArrayType());
211        CodeGenFunction::Destroyer *Destroy;
212        CleanupKind CleanupKind;
213        if (Lifetime == Qualifiers::OCL_Strong) {
214          const ValueDecl *VD = M->getExtendingDecl();
215          bool Precise =
216              VD && isa<VarDecl>(VD) && VD->hasAttr<ObjCPreciseLifetimeAttr>();
217          CleanupKind = CGF.getARCCleanupKind();
218          Destroy = Precise ? &CodeGenFunction::destroyARCStrongPrecise
219                            : &CodeGenFunction::destroyARCStrongImprecise;
220        } else {
221          // __weak objects always get EH cleanups; otherwise, exceptions
222          // could cause really nasty crashes instead of mere leaks.
223          CleanupKind = NormalAndEHCleanup;
224          Destroy = &CodeGenFunction::destroyARCWeak;
225        }
226        if (Duration == SD_FullExpression)
227          CGF.pushDestroy(CleanupKind, ReferenceTemporary,
228                          ObjCARCReferenceLifetimeType, *Destroy,
229                          CleanupKind & EHCleanup);
230        else
231          CGF.pushLifetimeExtendedDestroy(CleanupKind, ReferenceTemporary,
232                                          ObjCARCReferenceLifetimeType,
233                                          *Destroy, CleanupKind & EHCleanup);
234        return;
235
236      case SD_Dynamic:
237        llvm_unreachable("temporary cannot have dynamic storage duration");
238      }
239      llvm_unreachable("unknown storage duration");
240    }
241  }
242
243  CXXDestructorDecl *ReferenceTemporaryDtor = 0;
244  if (const RecordType *RT =
245          E->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
246    // Get the destructor for the reference temporary.
247    CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
248    if (!ClassDecl->hasTrivialDestructor())
249      ReferenceTemporaryDtor = ClassDecl->getDestructor();
250  }
251
252  if (!ReferenceTemporaryDtor)
253    return;
254
255  // Call the destructor for the temporary.
256  switch (M->getStorageDuration()) {
257  case SD_Static:
258  case SD_Thread: {
259    llvm::Constant *CleanupFn;
260    llvm::Constant *CleanupArg;
261    if (E->getType()->isArrayType()) {
262      CleanupFn = CodeGenFunction(CGF.CGM).generateDestroyHelper(
263          cast<llvm::Constant>(ReferenceTemporary), E->getType(),
264          CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions);
265      CleanupArg = llvm::Constant::getNullValue(CGF.Int8PtrTy);
266    } else {
267      CleanupFn =
268        CGF.CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
269      CleanupArg = cast<llvm::Constant>(ReferenceTemporary);
270    }
271    CGF.CGM.getCXXABI().registerGlobalDtor(
272        CGF, *cast<VarDecl>(M->getExtendingDecl()), CleanupFn, CleanupArg);
273    break;
274  }
275
276  case SD_FullExpression:
277    CGF.pushDestroy(NormalAndEHCleanup, ReferenceTemporary, E->getType(),
278                    CodeGenFunction::destroyCXXObject,
279                    CGF.getLangOpts().Exceptions);
280    break;
281
282  case SD_Automatic:
283    CGF.pushLifetimeExtendedDestroy(NormalAndEHCleanup,
284                                    ReferenceTemporary, E->getType(),
285                                    CodeGenFunction::destroyCXXObject,
286                                    CGF.getLangOpts().Exceptions);
287    break;
288
289  case SD_Dynamic:
290    llvm_unreachable("temporary cannot have dynamic storage duration");
291  }
292}
293
294static llvm::Value *
295createReferenceTemporary(CodeGenFunction &CGF,
296                         const MaterializeTemporaryExpr *M, const Expr *Inner) {
297  switch (M->getStorageDuration()) {
298  case SD_FullExpression:
299  case SD_Automatic:
300    return CGF.CreateMemTemp(Inner->getType(), "ref.tmp");
301
302  case SD_Thread:
303  case SD_Static:
304    return CGF.CGM.GetAddrOfGlobalTemporary(M, Inner);
305
306  case SD_Dynamic:
307    llvm_unreachable("temporary can't have dynamic storage duration");
308  }
309  llvm_unreachable("unknown storage duration");
310}
311
312LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
313                                           const MaterializeTemporaryExpr *M) {
314  const Expr *E = M->GetTemporaryExpr();
315
316  if (getLangOpts().ObjCAutoRefCount &&
317      M->getType()->isObjCLifetimeType() &&
318      M->getType().getObjCLifetime() != Qualifiers::OCL_None &&
319      M->getType().getObjCLifetime() != Qualifiers::OCL_ExplicitNone) {
320    // FIXME: Fold this into the general case below.
321    llvm::Value *Object = createReferenceTemporary(*this, M, E);
322    LValue RefTempDst = MakeAddrLValue(Object, M->getType());
323
324    if (llvm::GlobalVariable *Var = dyn_cast<llvm::GlobalVariable>(Object)) {
325      // We should not have emitted the initializer for this temporary as a
326      // constant.
327      assert(!Var->hasInitializer());
328      Var->setInitializer(CGM.EmitNullConstant(E->getType()));
329    }
330
331    EmitScalarInit(E, M->getExtendingDecl(), RefTempDst, false);
332
333    pushTemporaryCleanup(*this, M, E, Object);
334    return RefTempDst;
335  }
336
337  SmallVector<const Expr *, 2> CommaLHSs;
338  SmallVector<SubobjectAdjustment, 2> Adjustments;
339  E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
340
341  for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
342    EmitIgnoredExpr(CommaLHSs[I]);
343
344  if (const OpaqueValueExpr *opaque = dyn_cast<OpaqueValueExpr>(E)) {
345    if (opaque->getType()->isRecordType()) {
346      assert(Adjustments.empty());
347      return EmitOpaqueValueLValue(opaque);
348    }
349  }
350
351  // Create and initialize the reference temporary.
352  llvm::Value *Object = createReferenceTemporary(*this, M, E);
353  if (llvm::GlobalVariable *Var = dyn_cast<llvm::GlobalVariable>(Object)) {
354    // If the temporary is a global and has a constant initializer, we may
355    // have already initialized it.
356    if (!Var->hasInitializer()) {
357      Var->setInitializer(CGM.EmitNullConstant(E->getType()));
358      EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
359    }
360  } else {
361    EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
362  }
363  pushTemporaryCleanup(*this, M, E, Object);
364
365  // Perform derived-to-base casts and/or field accesses, to get from the
366  // temporary object we created (and, potentially, for which we extended
367  // the lifetime) to the subobject we're binding the reference to.
368  for (unsigned I = Adjustments.size(); I != 0; --I) {
369    SubobjectAdjustment &Adjustment = Adjustments[I-1];
370    switch (Adjustment.Kind) {
371    case SubobjectAdjustment::DerivedToBaseAdjustment:
372      Object =
373          GetAddressOfBaseClass(Object, Adjustment.DerivedToBase.DerivedClass,
374                                Adjustment.DerivedToBase.BasePath->path_begin(),
375                                Adjustment.DerivedToBase.BasePath->path_end(),
376                                /*NullCheckValue=*/ false);
377      break;
378
379    case SubobjectAdjustment::FieldAdjustment: {
380      LValue LV = MakeAddrLValue(Object, E->getType());
381      LV = EmitLValueForField(LV, Adjustment.Field);
382      assert(LV.isSimple() &&
383             "materialized temporary field is not a simple lvalue");
384      Object = LV.getAddress();
385      break;
386    }
387
388    case SubobjectAdjustment::MemberPointerAdjustment: {
389      llvm::Value *Ptr = EmitScalarExpr(Adjustment.Ptr.RHS);
390      Object = CGM.getCXXABI().EmitMemberDataPointerAddress(
391                    *this, Object, Ptr, Adjustment.Ptr.MPT);
392      break;
393    }
394    }
395  }
396
397  return MakeAddrLValue(Object, M->getType());
398}
399
400RValue
401CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E) {
402  // Emit the expression as an lvalue.
403  LValue LV = EmitLValue(E);
404  assert(LV.isSimple());
405  llvm::Value *Value = LV.getAddress();
406
407  if (SanitizePerformTypeCheck && !E->getType()->isFunctionType()) {
408    // C++11 [dcl.ref]p5 (as amended by core issue 453):
409    //   If a glvalue to which a reference is directly bound designates neither
410    //   an existing object or function of an appropriate type nor a region of
411    //   storage of suitable size and alignment to contain an object of the
412    //   reference's type, the behavior is undefined.
413    QualType Ty = E->getType();
414    EmitTypeCheck(TCK_ReferenceBinding, E->getExprLoc(), Value, Ty);
415  }
416
417  return RValue::get(Value);
418}
419
420
421/// getAccessedFieldNo - Given an encoded value and a result number, return the
422/// input field number being accessed.
423unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
424                                             const llvm::Constant *Elts) {
425  return cast<llvm::ConstantInt>(Elts->getAggregateElement(Idx))
426      ->getZExtValue();
427}
428
429/// Emit the hash_16_bytes function from include/llvm/ADT/Hashing.h.
430static llvm::Value *emitHash16Bytes(CGBuilderTy &Builder, llvm::Value *Low,
431                                    llvm::Value *High) {
432  llvm::Value *KMul = Builder.getInt64(0x9ddfea08eb382d69ULL);
433  llvm::Value *K47 = Builder.getInt64(47);
434  llvm::Value *A0 = Builder.CreateMul(Builder.CreateXor(Low, High), KMul);
435  llvm::Value *A1 = Builder.CreateXor(Builder.CreateLShr(A0, K47), A0);
436  llvm::Value *B0 = Builder.CreateMul(Builder.CreateXor(High, A1), KMul);
437  llvm::Value *B1 = Builder.CreateXor(Builder.CreateLShr(B0, K47), B0);
438  return Builder.CreateMul(B1, KMul);
439}
440
441void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
442                                    llvm::Value *Address,
443                                    QualType Ty, CharUnits Alignment) {
444  if (!SanitizePerformTypeCheck)
445    return;
446
447  // Don't check pointers outside the default address space. The null check
448  // isn't correct, the object-size check isn't supported by LLVM, and we can't
449  // communicate the addresses to the runtime handler for the vptr check.
450  if (Address->getType()->getPointerAddressSpace())
451    return;
452
453  llvm::Value *Cond = 0;
454  llvm::BasicBlock *Done = 0;
455
456  if (SanOpts->Null) {
457    // The glvalue must not be an empty glvalue.
458    Cond = Builder.CreateICmpNE(
459        Address, llvm::Constant::getNullValue(Address->getType()));
460
461    if (TCK == TCK_DowncastPointer) {
462      // When performing a pointer downcast, it's OK if the value is null.
463      // Skip the remaining checks in that case.
464      Done = createBasicBlock("null");
465      llvm::BasicBlock *Rest = createBasicBlock("not.null");
466      Builder.CreateCondBr(Cond, Rest, Done);
467      EmitBlock(Rest);
468      Cond = 0;
469    }
470  }
471
472  if (SanOpts->ObjectSize && !Ty->isIncompleteType()) {
473    uint64_t Size = getContext().getTypeSizeInChars(Ty).getQuantity();
474
475    // The glvalue must refer to a large enough storage region.
476    // FIXME: If Address Sanitizer is enabled, insert dynamic instrumentation
477    //        to check this.
478    llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, IntPtrTy);
479    llvm::Value *Min = Builder.getFalse();
480    llvm::Value *CastAddr = Builder.CreateBitCast(Address, Int8PtrTy);
481    llvm::Value *LargeEnough =
482        Builder.CreateICmpUGE(Builder.CreateCall2(F, CastAddr, Min),
483                              llvm::ConstantInt::get(IntPtrTy, Size));
484    Cond = Cond ? Builder.CreateAnd(Cond, LargeEnough) : LargeEnough;
485  }
486
487  uint64_t AlignVal = 0;
488
489  if (SanOpts->Alignment) {
490    AlignVal = Alignment.getQuantity();
491    if (!Ty->isIncompleteType() && !AlignVal)
492      AlignVal = getContext().getTypeAlignInChars(Ty).getQuantity();
493
494    // The glvalue must be suitably aligned.
495    if (AlignVal) {
496      llvm::Value *Align =
497          Builder.CreateAnd(Builder.CreatePtrToInt(Address, IntPtrTy),
498                            llvm::ConstantInt::get(IntPtrTy, AlignVal - 1));
499      llvm::Value *Aligned =
500        Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0));
501      Cond = Cond ? Builder.CreateAnd(Cond, Aligned) : Aligned;
502    }
503  }
504
505  if (Cond) {
506    llvm::Constant *StaticData[] = {
507      EmitCheckSourceLocation(Loc),
508      EmitCheckTypeDescriptor(Ty),
509      llvm::ConstantInt::get(SizeTy, AlignVal),
510      llvm::ConstantInt::get(Int8Ty, TCK)
511    };
512    EmitCheck(Cond, "type_mismatch", StaticData, Address, CRK_Recoverable);
513  }
514
515  // If possible, check that the vptr indicates that there is a subobject of
516  // type Ty at offset zero within this object.
517  //
518  // C++11 [basic.life]p5,6:
519  //   [For storage which does not refer to an object within its lifetime]
520  //   The program has undefined behavior if:
521  //    -- the [pointer or glvalue] is used to access a non-static data member
522  //       or call a non-static member function
523  CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
524  if (SanOpts->Vptr &&
525      (TCK == TCK_MemberAccess || TCK == TCK_MemberCall ||
526       TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference) &&
527      RD && RD->hasDefinition() && RD->isDynamicClass()) {
528    // Compute a hash of the mangled name of the type.
529    //
530    // FIXME: This is not guaranteed to be deterministic! Move to a
531    //        fingerprinting mechanism once LLVM provides one. For the time
532    //        being the implementation happens to be deterministic.
533    SmallString<64> MangledName;
534    llvm::raw_svector_ostream Out(MangledName);
535    CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty.getUnqualifiedType(),
536                                                     Out);
537    llvm::hash_code TypeHash = hash_value(Out.str());
538
539    // Load the vptr, and compute hash_16_bytes(TypeHash, vptr).
540    llvm::Value *Low = llvm::ConstantInt::get(Int64Ty, TypeHash);
541    llvm::Type *VPtrTy = llvm::PointerType::get(IntPtrTy, 0);
542    llvm::Value *VPtrAddr = Builder.CreateBitCast(Address, VPtrTy);
543    llvm::Value *VPtrVal = Builder.CreateLoad(VPtrAddr);
544    llvm::Value *High = Builder.CreateZExt(VPtrVal, Int64Ty);
545
546    llvm::Value *Hash = emitHash16Bytes(Builder, Low, High);
547    Hash = Builder.CreateTrunc(Hash, IntPtrTy);
548
549    // Look the hash up in our cache.
550    const int CacheSize = 128;
551    llvm::Type *HashTable = llvm::ArrayType::get(IntPtrTy, CacheSize);
552    llvm::Value *Cache = CGM.CreateRuntimeVariable(HashTable,
553                                                   "__ubsan_vptr_type_cache");
554    llvm::Value *Slot = Builder.CreateAnd(Hash,
555                                          llvm::ConstantInt::get(IntPtrTy,
556                                                                 CacheSize-1));
557    llvm::Value *Indices[] = { Builder.getInt32(0), Slot };
558    llvm::Value *CacheVal =
559      Builder.CreateLoad(Builder.CreateInBoundsGEP(Cache, Indices));
560
561    // If the hash isn't in the cache, call a runtime handler to perform the
562    // hard work of checking whether the vptr is for an object of the right
563    // type. This will either fill in the cache and return, or produce a
564    // diagnostic.
565    llvm::Constant *StaticData[] = {
566      EmitCheckSourceLocation(Loc),
567      EmitCheckTypeDescriptor(Ty),
568      CGM.GetAddrOfRTTIDescriptor(Ty.getUnqualifiedType()),
569      llvm::ConstantInt::get(Int8Ty, TCK)
570    };
571    llvm::Value *DynamicData[] = { Address, Hash };
572    EmitCheck(Builder.CreateICmpEQ(CacheVal, Hash),
573              "dynamic_type_cache_miss", StaticData, DynamicData,
574              CRK_AlwaysRecoverable);
575  }
576
577  if (Done) {
578    Builder.CreateBr(Done);
579    EmitBlock(Done);
580  }
581}
582
583/// Determine whether this expression refers to a flexible array member in a
584/// struct. We disable array bounds checks for such members.
585static bool isFlexibleArrayMemberExpr(const Expr *E) {
586  // For compatibility with existing code, we treat arrays of length 0 or
587  // 1 as flexible array members.
588  const ArrayType *AT = E->getType()->castAsArrayTypeUnsafe();
589  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT)) {
590    if (CAT->getSize().ugt(1))
591      return false;
592  } else if (!isa<IncompleteArrayType>(AT))
593    return false;
594
595  E = E->IgnoreParens();
596
597  // A flexible array member must be the last member in the class.
598  if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
599    // FIXME: If the base type of the member expr is not FD->getParent(),
600    // this should not be treated as a flexible array member access.
601    if (const FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
602      RecordDecl::field_iterator FI(
603          DeclContext::decl_iterator(const_cast<FieldDecl *>(FD)));
604      return ++FI == FD->getParent()->field_end();
605    }
606  }
607
608  return false;
609}
610
611/// If Base is known to point to the start of an array, return the length of
612/// that array. Return 0 if the length cannot be determined.
613static llvm::Value *getArrayIndexingBound(
614    CodeGenFunction &CGF, const Expr *Base, QualType &IndexedType) {
615  // For the vector indexing extension, the bound is the number of elements.
616  if (const VectorType *VT = Base->getType()->getAs<VectorType>()) {
617    IndexedType = Base->getType();
618    return CGF.Builder.getInt32(VT->getNumElements());
619  }
620
621  Base = Base->IgnoreParens();
622
623  if (const CastExpr *CE = dyn_cast<CastExpr>(Base)) {
624    if (CE->getCastKind() == CK_ArrayToPointerDecay &&
625        !isFlexibleArrayMemberExpr(CE->getSubExpr())) {
626      IndexedType = CE->getSubExpr()->getType();
627      const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe();
628      if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
629        return CGF.Builder.getInt(CAT->getSize());
630      else if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(AT))
631        return CGF.getVLASize(VAT).first;
632    }
633  }
634
635  return 0;
636}
637
638void CodeGenFunction::EmitBoundsCheck(const Expr *E, const Expr *Base,
639                                      llvm::Value *Index, QualType IndexType,
640                                      bool Accessed) {
641  assert(SanOpts->Bounds && "should not be called unless adding bounds checks");
642
643  QualType IndexedType;
644  llvm::Value *Bound = getArrayIndexingBound(*this, Base, IndexedType);
645  if (!Bound)
646    return;
647
648  bool IndexSigned = IndexType->isSignedIntegerOrEnumerationType();
649  llvm::Value *IndexVal = Builder.CreateIntCast(Index, SizeTy, IndexSigned);
650  llvm::Value *BoundVal = Builder.CreateIntCast(Bound, SizeTy, false);
651
652  llvm::Constant *StaticData[] = {
653    EmitCheckSourceLocation(E->getExprLoc()),
654    EmitCheckTypeDescriptor(IndexedType),
655    EmitCheckTypeDescriptor(IndexType)
656  };
657  llvm::Value *Check = Accessed ? Builder.CreateICmpULT(IndexVal, BoundVal)
658                                : Builder.CreateICmpULE(IndexVal, BoundVal);
659  EmitCheck(Check, "out_of_bounds", StaticData, Index, CRK_Recoverable);
660}
661
662
663CodeGenFunction::ComplexPairTy CodeGenFunction::
664EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
665                         bool isInc, bool isPre) {
666  ComplexPairTy InVal = EmitLoadOfComplex(LV);
667
668  llvm::Value *NextVal;
669  if (isa<llvm::IntegerType>(InVal.first->getType())) {
670    uint64_t AmountVal = isInc ? 1 : -1;
671    NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
672
673    // Add the inc/dec to the real part.
674    NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
675  } else {
676    QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
677    llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
678    if (!isInc)
679      FVal.changeSign();
680    NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
681
682    // Add the inc/dec to the real part.
683    NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
684  }
685
686  ComplexPairTy IncVal(NextVal, InVal.second);
687
688  // Store the updated result through the lvalue.
689  EmitStoreOfComplex(IncVal, LV, /*init*/ false);
690
691  // If this is a postinc, return the value read from memory, otherwise use the
692  // updated value.
693  return isPre ? IncVal : InVal;
694}
695
696
697//===----------------------------------------------------------------------===//
698//                         LValue Expression Emission
699//===----------------------------------------------------------------------===//
700
701RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
702  if (Ty->isVoidType())
703    return RValue::get(0);
704
705  switch (getEvaluationKind(Ty)) {
706  case TEK_Complex: {
707    llvm::Type *EltTy =
708      ConvertType(Ty->castAs<ComplexType>()->getElementType());
709    llvm::Value *U = llvm::UndefValue::get(EltTy);
710    return RValue::getComplex(std::make_pair(U, U));
711  }
712
713  // If this is a use of an undefined aggregate type, the aggregate must have an
714  // identifiable address.  Just because the contents of the value are undefined
715  // doesn't mean that the address can't be taken and compared.
716  case TEK_Aggregate: {
717    llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
718    return RValue::getAggregate(DestPtr);
719  }
720
721  case TEK_Scalar:
722    return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
723  }
724  llvm_unreachable("bad evaluation kind");
725}
726
727RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
728                                              const char *Name) {
729  ErrorUnsupported(E, Name);
730  return GetUndefRValue(E->getType());
731}
732
733LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
734                                              const char *Name) {
735  ErrorUnsupported(E, Name);
736  llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
737  return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
738}
739
740LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) {
741  LValue LV;
742  if (SanOpts->Bounds && isa<ArraySubscriptExpr>(E))
743    LV = EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E), /*Accessed*/true);
744  else
745    LV = EmitLValue(E);
746  if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
747    EmitTypeCheck(TCK, E->getExprLoc(), LV.getAddress(),
748                  E->getType(), LV.getAlignment());
749  return LV;
750}
751
752/// EmitLValue - Emit code to compute a designator that specifies the location
753/// of the expression.
754///
755/// This can return one of two things: a simple address or a bitfield reference.
756/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
757/// an LLVM pointer type.
758///
759/// If this returns a bitfield reference, nothing about the pointee type of the
760/// LLVM value is known: For example, it may not be a pointer to an integer.
761///
762/// If this returns a normal address, and if the lvalue's C type is fixed size,
763/// this method guarantees that the returned pointer type will point to an LLVM
764/// type of the same size of the lvalue's type.  If the lvalue has a variable
765/// length type, this is not possible.
766///
767LValue CodeGenFunction::EmitLValue(const Expr *E) {
768  switch (E->getStmtClass()) {
769  default: return EmitUnsupportedLValue(E, "l-value expression");
770
771  case Expr::ObjCPropertyRefExprClass:
772    llvm_unreachable("cannot emit a property reference directly");
773
774  case Expr::ObjCSelectorExprClass:
775    return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
776  case Expr::ObjCIsaExprClass:
777    return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
778  case Expr::BinaryOperatorClass:
779    return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
780  case Expr::CompoundAssignOperatorClass:
781    if (!E->getType()->isAnyComplexType())
782      return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
783    return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
784  case Expr::CallExprClass:
785  case Expr::CXXMemberCallExprClass:
786  case Expr::CXXOperatorCallExprClass:
787  case Expr::UserDefinedLiteralClass:
788    return EmitCallExprLValue(cast<CallExpr>(E));
789  case Expr::VAArgExprClass:
790    return EmitVAArgExprLValue(cast<VAArgExpr>(E));
791  case Expr::DeclRefExprClass:
792    return EmitDeclRefLValue(cast<DeclRefExpr>(E));
793  case Expr::ParenExprClass:
794    return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
795  case Expr::GenericSelectionExprClass:
796    return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
797  case Expr::PredefinedExprClass:
798    return EmitPredefinedLValue(cast<PredefinedExpr>(E));
799  case Expr::StringLiteralClass:
800    return EmitStringLiteralLValue(cast<StringLiteral>(E));
801  case Expr::ObjCEncodeExprClass:
802    return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
803  case Expr::PseudoObjectExprClass:
804    return EmitPseudoObjectLValue(cast<PseudoObjectExpr>(E));
805  case Expr::InitListExprClass:
806    return EmitInitListLValue(cast<InitListExpr>(E));
807  case Expr::CXXTemporaryObjectExprClass:
808  case Expr::CXXConstructExprClass:
809    return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
810  case Expr::CXXBindTemporaryExprClass:
811    return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
812  case Expr::CXXUuidofExprClass:
813    return EmitCXXUuidofLValue(cast<CXXUuidofExpr>(E));
814  case Expr::LambdaExprClass:
815    return EmitLambdaLValue(cast<LambdaExpr>(E));
816
817  case Expr::ExprWithCleanupsClass: {
818    const ExprWithCleanups *cleanups = cast<ExprWithCleanups>(E);
819    enterFullExpression(cleanups);
820    RunCleanupsScope Scope(*this);
821    return EmitLValue(cleanups->getSubExpr());
822  }
823
824  case Expr::CXXDefaultArgExprClass:
825    return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
826  case Expr::CXXDefaultInitExprClass: {
827    CXXDefaultInitExprScope Scope(*this);
828    return EmitLValue(cast<CXXDefaultInitExpr>(E)->getExpr());
829  }
830  case Expr::CXXTypeidExprClass:
831    return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
832
833  case Expr::ObjCMessageExprClass:
834    return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
835  case Expr::ObjCIvarRefExprClass:
836    return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
837  case Expr::StmtExprClass:
838    return EmitStmtExprLValue(cast<StmtExpr>(E));
839  case Expr::UnaryOperatorClass:
840    return EmitUnaryOpLValue(cast<UnaryOperator>(E));
841  case Expr::ArraySubscriptExprClass:
842    return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
843  case Expr::ExtVectorElementExprClass:
844    return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
845  case Expr::MemberExprClass:
846    return EmitMemberExpr(cast<MemberExpr>(E));
847  case Expr::CompoundLiteralExprClass:
848    return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
849  case Expr::ConditionalOperatorClass:
850    return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
851  case Expr::BinaryConditionalOperatorClass:
852    return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
853  case Expr::ChooseExprClass:
854    return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr());
855  case Expr::OpaqueValueExprClass:
856    return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
857  case Expr::SubstNonTypeTemplateParmExprClass:
858    return EmitLValue(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
859  case Expr::ImplicitCastExprClass:
860  case Expr::CStyleCastExprClass:
861  case Expr::CXXFunctionalCastExprClass:
862  case Expr::CXXStaticCastExprClass:
863  case Expr::CXXDynamicCastExprClass:
864  case Expr::CXXReinterpretCastExprClass:
865  case Expr::CXXConstCastExprClass:
866  case Expr::ObjCBridgedCastExprClass:
867    return EmitCastLValue(cast<CastExpr>(E));
868
869  case Expr::MaterializeTemporaryExprClass:
870    return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
871  }
872}
873
874/// Given an object of the given canonical type, can we safely copy a
875/// value out of it based on its initializer?
876static bool isConstantEmittableObjectType(QualType type) {
877  assert(type.isCanonical());
878  assert(!type->isReferenceType());
879
880  // Must be const-qualified but non-volatile.
881  Qualifiers qs = type.getLocalQualifiers();
882  if (!qs.hasConst() || qs.hasVolatile()) return false;
883
884  // Otherwise, all object types satisfy this except C++ classes with
885  // mutable subobjects or non-trivial copy/destroy behavior.
886  if (const RecordType *RT = dyn_cast<RecordType>(type))
887    if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
888      if (RD->hasMutableFields() || !RD->isTrivial())
889        return false;
890
891  return true;
892}
893
894/// Can we constant-emit a load of a reference to a variable of the
895/// given type?  This is different from predicates like
896/// Decl::isUsableInConstantExpressions because we do want it to apply
897/// in situations that don't necessarily satisfy the language's rules
898/// for this (e.g. C++'s ODR-use rules).  For example, we want to able
899/// to do this with const float variables even if those variables
900/// aren't marked 'constexpr'.
901enum ConstantEmissionKind {
902  CEK_None,
903  CEK_AsReferenceOnly,
904  CEK_AsValueOrReference,
905  CEK_AsValueOnly
906};
907static ConstantEmissionKind checkVarTypeForConstantEmission(QualType type) {
908  type = type.getCanonicalType();
909  if (const ReferenceType *ref = dyn_cast<ReferenceType>(type)) {
910    if (isConstantEmittableObjectType(ref->getPointeeType()))
911      return CEK_AsValueOrReference;
912    return CEK_AsReferenceOnly;
913  }
914  if (isConstantEmittableObjectType(type))
915    return CEK_AsValueOnly;
916  return CEK_None;
917}
918
919/// Try to emit a reference to the given value without producing it as
920/// an l-value.  This is actually more than an optimization: we can't
921/// produce an l-value for variables that we never actually captured
922/// in a block or lambda, which means const int variables or constexpr
923/// literals or similar.
924CodeGenFunction::ConstantEmission
925CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
926  ValueDecl *value = refExpr->getDecl();
927
928  // The value needs to be an enum constant or a constant variable.
929  ConstantEmissionKind CEK;
930  if (isa<ParmVarDecl>(value)) {
931    CEK = CEK_None;
932  } else if (VarDecl *var = dyn_cast<VarDecl>(value)) {
933    CEK = checkVarTypeForConstantEmission(var->getType());
934  } else if (isa<EnumConstantDecl>(value)) {
935    CEK = CEK_AsValueOnly;
936  } else {
937    CEK = CEK_None;
938  }
939  if (CEK == CEK_None) return ConstantEmission();
940
941  Expr::EvalResult result;
942  bool resultIsReference;
943  QualType resultType;
944
945  // It's best to evaluate all the way as an r-value if that's permitted.
946  if (CEK != CEK_AsReferenceOnly &&
947      refExpr->EvaluateAsRValue(result, getContext())) {
948    resultIsReference = false;
949    resultType = refExpr->getType();
950
951  // Otherwise, try to evaluate as an l-value.
952  } else if (CEK != CEK_AsValueOnly &&
953             refExpr->EvaluateAsLValue(result, getContext())) {
954    resultIsReference = true;
955    resultType = value->getType();
956
957  // Failure.
958  } else {
959    return ConstantEmission();
960  }
961
962  // In any case, if the initializer has side-effects, abandon ship.
963  if (result.HasSideEffects)
964    return ConstantEmission();
965
966  // Emit as a constant.
967  llvm::Constant *C = CGM.EmitConstantValue(result.Val, resultType, this);
968
969  // Make sure we emit a debug reference to the global variable.
970  // This should probably fire even for
971  if (isa<VarDecl>(value)) {
972    if (!getContext().DeclMustBeEmitted(cast<VarDecl>(value)))
973      EmitDeclRefExprDbgValue(refExpr, C);
974  } else {
975    assert(isa<EnumConstantDecl>(value));
976    EmitDeclRefExprDbgValue(refExpr, C);
977  }
978
979  // If we emitted a reference constant, we need to dereference that.
980  if (resultIsReference)
981    return ConstantEmission::forReference(C);
982
983  return ConstantEmission::forValue(C);
984}
985
986llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue) {
987  return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
988                          lvalue.getAlignment().getQuantity(),
989                          lvalue.getType(), lvalue.getTBAAInfo(),
990                          lvalue.getTBAABaseType(), lvalue.getTBAAOffset());
991}
992
993static bool hasBooleanRepresentation(QualType Ty) {
994  if (Ty->isBooleanType())
995    return true;
996
997  if (const EnumType *ET = Ty->getAs<EnumType>())
998    return ET->getDecl()->getIntegerType()->isBooleanType();
999
1000  if (const AtomicType *AT = Ty->getAs<AtomicType>())
1001    return hasBooleanRepresentation(AT->getValueType());
1002
1003  return false;
1004}
1005
1006static bool getRangeForType(CodeGenFunction &CGF, QualType Ty,
1007                            llvm::APInt &Min, llvm::APInt &End,
1008                            bool StrictEnums) {
1009  const EnumType *ET = Ty->getAs<EnumType>();
1010  bool IsRegularCPlusPlusEnum = CGF.getLangOpts().CPlusPlus && StrictEnums &&
1011                                ET && !ET->getDecl()->isFixed();
1012  bool IsBool = hasBooleanRepresentation(Ty);
1013  if (!IsBool && !IsRegularCPlusPlusEnum)
1014    return false;
1015
1016  if (IsBool) {
1017    Min = llvm::APInt(CGF.getContext().getTypeSize(Ty), 0);
1018    End = llvm::APInt(CGF.getContext().getTypeSize(Ty), 2);
1019  } else {
1020    const EnumDecl *ED = ET->getDecl();
1021    llvm::Type *LTy = CGF.ConvertTypeForMem(ED->getIntegerType());
1022    unsigned Bitwidth = LTy->getScalarSizeInBits();
1023    unsigned NumNegativeBits = ED->getNumNegativeBits();
1024    unsigned NumPositiveBits = ED->getNumPositiveBits();
1025
1026    if (NumNegativeBits) {
1027      unsigned NumBits = std::max(NumNegativeBits, NumPositiveBits + 1);
1028      assert(NumBits <= Bitwidth);
1029      End = llvm::APInt(Bitwidth, 1) << (NumBits - 1);
1030      Min = -End;
1031    } else {
1032      assert(NumPositiveBits <= Bitwidth);
1033      End = llvm::APInt(Bitwidth, 1) << NumPositiveBits;
1034      Min = llvm::APInt(Bitwidth, 0);
1035    }
1036  }
1037  return true;
1038}
1039
1040llvm::MDNode *CodeGenFunction::getRangeForLoadFromType(QualType Ty) {
1041  llvm::APInt Min, End;
1042  if (!getRangeForType(*this, Ty, Min, End,
1043                       CGM.getCodeGenOpts().StrictEnums))
1044    return 0;
1045
1046  llvm::MDBuilder MDHelper(getLLVMContext());
1047  return MDHelper.createRange(Min, End);
1048}
1049
1050llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
1051                                              unsigned Alignment, QualType Ty,
1052                                              llvm::MDNode *TBAAInfo,
1053                                              QualType TBAABaseType,
1054                                              uint64_t TBAAOffset) {
1055  // For better performance, handle vector loads differently.
1056  if (Ty->isVectorType()) {
1057    llvm::Value *V;
1058    const llvm::Type *EltTy =
1059    cast<llvm::PointerType>(Addr->getType())->getElementType();
1060
1061    const llvm::VectorType *VTy = cast<llvm::VectorType>(EltTy);
1062
1063    // Handle vectors of size 3, like size 4 for better performance.
1064    if (VTy->getNumElements() == 3) {
1065
1066      // Bitcast to vec4 type.
1067      llvm::VectorType *vec4Ty = llvm::VectorType::get(VTy->getElementType(),
1068                                                         4);
1069      llvm::PointerType *ptVec4Ty =
1070      llvm::PointerType::get(vec4Ty,
1071                             (cast<llvm::PointerType>(
1072                                      Addr->getType()))->getAddressSpace());
1073      llvm::Value *Cast = Builder.CreateBitCast(Addr, ptVec4Ty,
1074                                                "castToVec4");
1075      // Now load value.
1076      llvm::Value *LoadVal = Builder.CreateLoad(Cast, Volatile, "loadVec4");
1077
1078      // Shuffle vector to get vec3.
1079      llvm::Constant *Mask[] = {
1080        llvm::ConstantInt::get(llvm::Type::getInt32Ty(getLLVMContext()), 0),
1081        llvm::ConstantInt::get(llvm::Type::getInt32Ty(getLLVMContext()), 1),
1082        llvm::ConstantInt::get(llvm::Type::getInt32Ty(getLLVMContext()), 2)
1083      };
1084
1085      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1086      V = Builder.CreateShuffleVector(LoadVal,
1087                                      llvm::UndefValue::get(vec4Ty),
1088                                      MaskV, "extractVec");
1089      return EmitFromMemory(V, Ty);
1090    }
1091  }
1092
1093  // Atomic operations have to be done on integral types.
1094  if (Ty->isAtomicType()) {
1095    LValue lvalue = LValue::MakeAddr(Addr, Ty,
1096                                     CharUnits::fromQuantity(Alignment),
1097                                     getContext(), TBAAInfo);
1098    return EmitAtomicLoad(lvalue).getScalarVal();
1099  }
1100
1101  llvm::LoadInst *Load = Builder.CreateLoad(Addr);
1102  if (Volatile)
1103    Load->setVolatile(true);
1104  if (Alignment)
1105    Load->setAlignment(Alignment);
1106  if (TBAAInfo) {
1107    llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
1108                                                      TBAAOffset);
1109    CGM.DecorateInstruction(Load, TBAAPath, false/*ConvertTypeToTag*/);
1110  }
1111
1112  if ((SanOpts->Bool && hasBooleanRepresentation(Ty)) ||
1113      (SanOpts->Enum && Ty->getAs<EnumType>())) {
1114    llvm::APInt Min, End;
1115    if (getRangeForType(*this, Ty, Min, End, true)) {
1116      --End;
1117      llvm::Value *Check;
1118      if (!Min)
1119        Check = Builder.CreateICmpULE(
1120          Load, llvm::ConstantInt::get(getLLVMContext(), End));
1121      else {
1122        llvm::Value *Upper = Builder.CreateICmpSLE(
1123          Load, llvm::ConstantInt::get(getLLVMContext(), End));
1124        llvm::Value *Lower = Builder.CreateICmpSGE(
1125          Load, llvm::ConstantInt::get(getLLVMContext(), Min));
1126        Check = Builder.CreateAnd(Upper, Lower);
1127      }
1128      // FIXME: Provide a SourceLocation.
1129      EmitCheck(Check, "load_invalid_value", EmitCheckTypeDescriptor(Ty),
1130                EmitCheckValue(Load), CRK_Recoverable);
1131    }
1132  } else if (CGM.getCodeGenOpts().OptimizationLevel > 0)
1133    if (llvm::MDNode *RangeInfo = getRangeForLoadFromType(Ty))
1134      Load->setMetadata(llvm::LLVMContext::MD_range, RangeInfo);
1135
1136  return EmitFromMemory(Load, Ty);
1137}
1138
1139llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
1140  // Bool has a different representation in memory than in registers.
1141  if (hasBooleanRepresentation(Ty)) {
1142    // This should really always be an i1, but sometimes it's already
1143    // an i8, and it's awkward to track those cases down.
1144    if (Value->getType()->isIntegerTy(1))
1145      return Builder.CreateZExt(Value, ConvertTypeForMem(Ty), "frombool");
1146    assert(Value->getType()->isIntegerTy(getContext().getTypeSize(Ty)) &&
1147           "wrong value rep of bool");
1148  }
1149
1150  return Value;
1151}
1152
1153llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
1154  // Bool has a different representation in memory than in registers.
1155  if (hasBooleanRepresentation(Ty)) {
1156    assert(Value->getType()->isIntegerTy(getContext().getTypeSize(Ty)) &&
1157           "wrong value rep of bool");
1158    return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
1159  }
1160
1161  return Value;
1162}
1163
1164void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
1165                                        bool Volatile, unsigned Alignment,
1166                                        QualType Ty,
1167                                        llvm::MDNode *TBAAInfo,
1168                                        bool isInit, QualType TBAABaseType,
1169                                        uint64_t TBAAOffset) {
1170
1171  // Handle vectors differently to get better performance.
1172  if (Ty->isVectorType()) {
1173    llvm::Type *SrcTy = Value->getType();
1174    llvm::VectorType *VecTy = cast<llvm::VectorType>(SrcTy);
1175    // Handle vec3 special.
1176    if (VecTy->getNumElements() == 3) {
1177      llvm::LLVMContext &VMContext = getLLVMContext();
1178
1179      // Our source is a vec3, do a shuffle vector to make it a vec4.
1180      SmallVector<llvm::Constant*, 4> Mask;
1181      Mask.push_back(llvm::ConstantInt::get(
1182                                            llvm::Type::getInt32Ty(VMContext),
1183                                            0));
1184      Mask.push_back(llvm::ConstantInt::get(
1185                                            llvm::Type::getInt32Ty(VMContext),
1186                                            1));
1187      Mask.push_back(llvm::ConstantInt::get(
1188                                            llvm::Type::getInt32Ty(VMContext),
1189                                            2));
1190      Mask.push_back(llvm::UndefValue::get(llvm::Type::getInt32Ty(VMContext)));
1191
1192      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1193      Value = Builder.CreateShuffleVector(Value,
1194                                          llvm::UndefValue::get(VecTy),
1195                                          MaskV, "extractVec");
1196      SrcTy = llvm::VectorType::get(VecTy->getElementType(), 4);
1197    }
1198    llvm::PointerType *DstPtr = cast<llvm::PointerType>(Addr->getType());
1199    if (DstPtr->getElementType() != SrcTy) {
1200      llvm::Type *MemTy =
1201      llvm::PointerType::get(SrcTy, DstPtr->getAddressSpace());
1202      Addr = Builder.CreateBitCast(Addr, MemTy, "storetmp");
1203    }
1204  }
1205
1206  Value = EmitToMemory(Value, Ty);
1207
1208  if (Ty->isAtomicType()) {
1209    EmitAtomicStore(RValue::get(Value),
1210                    LValue::MakeAddr(Addr, Ty,
1211                                     CharUnits::fromQuantity(Alignment),
1212                                     getContext(), TBAAInfo),
1213                    isInit);
1214    return;
1215  }
1216
1217  llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
1218  if (Alignment)
1219    Store->setAlignment(Alignment);
1220  if (TBAAInfo) {
1221    llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
1222                                                      TBAAOffset);
1223    CGM.DecorateInstruction(Store, TBAAPath, false/*ConvertTypeToTag*/);
1224  }
1225}
1226
1227void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue,
1228                                        bool isInit) {
1229  EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
1230                    lvalue.getAlignment().getQuantity(), lvalue.getType(),
1231                    lvalue.getTBAAInfo(), isInit, lvalue.getTBAABaseType(),
1232                    lvalue.getTBAAOffset());
1233}
1234
1235/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
1236/// method emits the address of the lvalue, then loads the result as an rvalue,
1237/// returning the rvalue.
1238RValue CodeGenFunction::EmitLoadOfLValue(LValue LV) {
1239  if (LV.isObjCWeak()) {
1240    // load of a __weak object.
1241    llvm::Value *AddrWeakObj = LV.getAddress();
1242    return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
1243                                                             AddrWeakObj));
1244  }
1245  if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) {
1246    llvm::Value *Object = EmitARCLoadWeakRetained(LV.getAddress());
1247    Object = EmitObjCConsumeObject(LV.getType(), Object);
1248    return RValue::get(Object);
1249  }
1250
1251  if (LV.isSimple()) {
1252    assert(!LV.getType()->isFunctionType());
1253
1254    // Everything needs a load.
1255    return RValue::get(EmitLoadOfScalar(LV));
1256  }
1257
1258  if (LV.isVectorElt()) {
1259    llvm::LoadInst *Load = Builder.CreateLoad(LV.getVectorAddr(),
1260                                              LV.isVolatileQualified());
1261    Load->setAlignment(LV.getAlignment().getQuantity());
1262    return RValue::get(Builder.CreateExtractElement(Load, LV.getVectorIdx(),
1263                                                    "vecext"));
1264  }
1265
1266  // If this is a reference to a subset of the elements of a vector, either
1267  // shuffle the input or extract/insert them as appropriate.
1268  if (LV.isExtVectorElt())
1269    return EmitLoadOfExtVectorElementLValue(LV);
1270
1271  assert(LV.isBitField() && "Unknown LValue type!");
1272  return EmitLoadOfBitfieldLValue(LV);
1273}
1274
1275RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV) {
1276  const CGBitFieldInfo &Info = LV.getBitFieldInfo();
1277
1278  // Get the output type.
1279  llvm::Type *ResLTy = ConvertType(LV.getType());
1280
1281  llvm::Value *Ptr = LV.getBitFieldAddr();
1282  llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(),
1283                                        "bf.load");
1284  cast<llvm::LoadInst>(Val)->setAlignment(Info.StorageAlignment);
1285
1286  if (Info.IsSigned) {
1287    assert(static_cast<unsigned>(Info.Offset + Info.Size) <= Info.StorageSize);
1288    unsigned HighBits = Info.StorageSize - Info.Offset - Info.Size;
1289    if (HighBits)
1290      Val = Builder.CreateShl(Val, HighBits, "bf.shl");
1291    if (Info.Offset + HighBits)
1292      Val = Builder.CreateAShr(Val, Info.Offset + HighBits, "bf.ashr");
1293  } else {
1294    if (Info.Offset)
1295      Val = Builder.CreateLShr(Val, Info.Offset, "bf.lshr");
1296    if (static_cast<unsigned>(Info.Offset) + Info.Size < Info.StorageSize)
1297      Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(Info.StorageSize,
1298                                                              Info.Size),
1299                              "bf.clear");
1300  }
1301  Val = Builder.CreateIntCast(Val, ResLTy, Info.IsSigned, "bf.cast");
1302
1303  return RValue::get(Val);
1304}
1305
1306// If this is a reference to a subset of the elements of a vector, create an
1307// appropriate shufflevector.
1308RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) {
1309  llvm::LoadInst *Load = Builder.CreateLoad(LV.getExtVectorAddr(),
1310                                            LV.isVolatileQualified());
1311  Load->setAlignment(LV.getAlignment().getQuantity());
1312  llvm::Value *Vec = Load;
1313
1314  const llvm::Constant *Elts = LV.getExtVectorElts();
1315
1316  // If the result of the expression is a non-vector type, we must be extracting
1317  // a single element.  Just codegen as an extractelement.
1318  const VectorType *ExprVT = LV.getType()->getAs<VectorType>();
1319  if (!ExprVT) {
1320    unsigned InIdx = getAccessedFieldNo(0, Elts);
1321    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1322    return RValue::get(Builder.CreateExtractElement(Vec, Elt));
1323  }
1324
1325  // Always use shuffle vector to try to retain the original program structure
1326  unsigned NumResultElts = ExprVT->getNumElements();
1327
1328  SmallVector<llvm::Constant*, 4> Mask;
1329  for (unsigned i = 0; i != NumResultElts; ++i)
1330    Mask.push_back(Builder.getInt32(getAccessedFieldNo(i, Elts)));
1331
1332  llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1333  Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()),
1334                                    MaskV);
1335  return RValue::get(Vec);
1336}
1337
1338
1339
1340/// EmitStoreThroughLValue - Store the specified rvalue into the specified
1341/// lvalue, where both are guaranteed to the have the same type, and that type
1342/// is 'Ty'.
1343void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst, bool isInit) {
1344  if (!Dst.isSimple()) {
1345    if (Dst.isVectorElt()) {
1346      // Read/modify/write the vector, inserting the new element.
1347      llvm::LoadInst *Load = Builder.CreateLoad(Dst.getVectorAddr(),
1348                                                Dst.isVolatileQualified());
1349      Load->setAlignment(Dst.getAlignment().getQuantity());
1350      llvm::Value *Vec = Load;
1351      Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
1352                                        Dst.getVectorIdx(), "vecins");
1353      llvm::StoreInst *Store = Builder.CreateStore(Vec, Dst.getVectorAddr(),
1354                                                   Dst.isVolatileQualified());
1355      Store->setAlignment(Dst.getAlignment().getQuantity());
1356      return;
1357    }
1358
1359    // If this is an update of extended vector elements, insert them as
1360    // appropriate.
1361    if (Dst.isExtVectorElt())
1362      return EmitStoreThroughExtVectorComponentLValue(Src, Dst);
1363
1364    assert(Dst.isBitField() && "Unknown LValue type");
1365    return EmitStoreThroughBitfieldLValue(Src, Dst);
1366  }
1367
1368  // There's special magic for assigning into an ARC-qualified l-value.
1369  if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) {
1370    switch (Lifetime) {
1371    case Qualifiers::OCL_None:
1372      llvm_unreachable("present but none");
1373
1374    case Qualifiers::OCL_ExplicitNone:
1375      // nothing special
1376      break;
1377
1378    case Qualifiers::OCL_Strong:
1379      EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
1380      return;
1381
1382    case Qualifiers::OCL_Weak:
1383      EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
1384      return;
1385
1386    case Qualifiers::OCL_Autoreleasing:
1387      Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(),
1388                                                     Src.getScalarVal()));
1389      // fall into the normal path
1390      break;
1391    }
1392  }
1393
1394  if (Dst.isObjCWeak() && !Dst.isNonGC()) {
1395    // load of a __weak object.
1396    llvm::Value *LvalueDst = Dst.getAddress();
1397    llvm::Value *src = Src.getScalarVal();
1398     CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
1399    return;
1400  }
1401
1402  if (Dst.isObjCStrong() && !Dst.isNonGC()) {
1403    // load of a __strong object.
1404    llvm::Value *LvalueDst = Dst.getAddress();
1405    llvm::Value *src = Src.getScalarVal();
1406    if (Dst.isObjCIvar()) {
1407      assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
1408      llvm::Type *ResultType = ConvertType(getContext().LongTy);
1409      llvm::Value *RHS = EmitScalarExpr(Dst.getBaseIvarExp());
1410      llvm::Value *dst = RHS;
1411      RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
1412      llvm::Value *LHS =
1413        Builder.CreatePtrToInt(LvalueDst, ResultType, "sub.ptr.lhs.cast");
1414      llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
1415      CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
1416                                              BytesBetween);
1417    } else if (Dst.isGlobalObjCRef()) {
1418      CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
1419                                                Dst.isThreadLocalRef());
1420    }
1421    else
1422      CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
1423    return;
1424  }
1425
1426  assert(Src.isScalar() && "Can't emit an agg store with this method");
1427  EmitStoreOfScalar(Src.getScalarVal(), Dst, isInit);
1428}
1429
1430void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
1431                                                     llvm::Value **Result) {
1432  const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
1433  llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
1434  llvm::Value *Ptr = Dst.getBitFieldAddr();
1435
1436  // Get the source value, truncated to the width of the bit-field.
1437  llvm::Value *SrcVal = Src.getScalarVal();
1438
1439  // Cast the source to the storage type and shift it into place.
1440  SrcVal = Builder.CreateIntCast(SrcVal,
1441                                 Ptr->getType()->getPointerElementType(),
1442                                 /*IsSigned=*/false);
1443  llvm::Value *MaskedVal = SrcVal;
1444
1445  // See if there are other bits in the bitfield's storage we'll need to load
1446  // and mask together with source before storing.
1447  if (Info.StorageSize != Info.Size) {
1448    assert(Info.StorageSize > Info.Size && "Invalid bitfield size.");
1449    llvm::Value *Val = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
1450                                          "bf.load");
1451    cast<llvm::LoadInst>(Val)->setAlignment(Info.StorageAlignment);
1452
1453    // Mask the source value as needed.
1454    if (!hasBooleanRepresentation(Dst.getType()))
1455      SrcVal = Builder.CreateAnd(SrcVal,
1456                                 llvm::APInt::getLowBitsSet(Info.StorageSize,
1457                                                            Info.Size),
1458                                 "bf.value");
1459    MaskedVal = SrcVal;
1460    if (Info.Offset)
1461      SrcVal = Builder.CreateShl(SrcVal, Info.Offset, "bf.shl");
1462
1463    // Mask out the original value.
1464    Val = Builder.CreateAnd(Val,
1465                            ~llvm::APInt::getBitsSet(Info.StorageSize,
1466                                                     Info.Offset,
1467                                                     Info.Offset + Info.Size),
1468                            "bf.clear");
1469
1470    // Or together the unchanged values and the source value.
1471    SrcVal = Builder.CreateOr(Val, SrcVal, "bf.set");
1472  } else {
1473    assert(Info.Offset == 0);
1474  }
1475
1476  // Write the new value back out.
1477  llvm::StoreInst *Store = Builder.CreateStore(SrcVal, Ptr,
1478                                               Dst.isVolatileQualified());
1479  Store->setAlignment(Info.StorageAlignment);
1480
1481  // Return the new value of the bit-field, if requested.
1482  if (Result) {
1483    llvm::Value *ResultVal = MaskedVal;
1484
1485    // Sign extend the value if needed.
1486    if (Info.IsSigned) {
1487      assert(Info.Size <= Info.StorageSize);
1488      unsigned HighBits = Info.StorageSize - Info.Size;
1489      if (HighBits) {
1490        ResultVal = Builder.CreateShl(ResultVal, HighBits, "bf.result.shl");
1491        ResultVal = Builder.CreateAShr(ResultVal, HighBits, "bf.result.ashr");
1492      }
1493    }
1494
1495    ResultVal = Builder.CreateIntCast(ResultVal, ResLTy, Info.IsSigned,
1496                                      "bf.result.cast");
1497    *Result = EmitFromMemory(ResultVal, Dst.getType());
1498  }
1499}
1500
1501void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
1502                                                               LValue Dst) {
1503  // This access turns into a read/modify/write of the vector.  Load the input
1504  // value now.
1505  llvm::LoadInst *Load = Builder.CreateLoad(Dst.getExtVectorAddr(),
1506                                            Dst.isVolatileQualified());
1507  Load->setAlignment(Dst.getAlignment().getQuantity());
1508  llvm::Value *Vec = Load;
1509  const llvm::Constant *Elts = Dst.getExtVectorElts();
1510
1511  llvm::Value *SrcVal = Src.getScalarVal();
1512
1513  if (const VectorType *VTy = Dst.getType()->getAs<VectorType>()) {
1514    unsigned NumSrcElts = VTy->getNumElements();
1515    unsigned NumDstElts =
1516       cast<llvm::VectorType>(Vec->getType())->getNumElements();
1517    if (NumDstElts == NumSrcElts) {
1518      // Use shuffle vector is the src and destination are the same number of
1519      // elements and restore the vector mask since it is on the side it will be
1520      // stored.
1521      SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
1522      for (unsigned i = 0; i != NumSrcElts; ++i)
1523        Mask[getAccessedFieldNo(i, Elts)] = Builder.getInt32(i);
1524
1525      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1526      Vec = Builder.CreateShuffleVector(SrcVal,
1527                                        llvm::UndefValue::get(Vec->getType()),
1528                                        MaskV);
1529    } else if (NumDstElts > NumSrcElts) {
1530      // Extended the source vector to the same length and then shuffle it
1531      // into the destination.
1532      // FIXME: since we're shuffling with undef, can we just use the indices
1533      //        into that?  This could be simpler.
1534      SmallVector<llvm::Constant*, 4> ExtMask;
1535      for (unsigned i = 0; i != NumSrcElts; ++i)
1536        ExtMask.push_back(Builder.getInt32(i));
1537      ExtMask.resize(NumDstElts, llvm::UndefValue::get(Int32Ty));
1538      llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
1539      llvm::Value *ExtSrcVal =
1540        Builder.CreateShuffleVector(SrcVal,
1541                                    llvm::UndefValue::get(SrcVal->getType()),
1542                                    ExtMaskV);
1543      // build identity
1544      SmallVector<llvm::Constant*, 4> Mask;
1545      for (unsigned i = 0; i != NumDstElts; ++i)
1546        Mask.push_back(Builder.getInt32(i));
1547
1548      // modify when what gets shuffled in
1549      for (unsigned i = 0; i != NumSrcElts; ++i)
1550        Mask[getAccessedFieldNo(i, Elts)] = Builder.getInt32(i+NumDstElts);
1551      llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
1552      Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV);
1553    } else {
1554      // We should never shorten the vector
1555      llvm_unreachable("unexpected shorten vector length");
1556    }
1557  } else {
1558    // If the Src is a scalar (not a vector) it must be updating one element.
1559    unsigned InIdx = getAccessedFieldNo(0, Elts);
1560    llvm::Value *Elt = llvm::ConstantInt::get(Int32Ty, InIdx);
1561    Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt);
1562  }
1563
1564  llvm::StoreInst *Store = Builder.CreateStore(Vec, Dst.getExtVectorAddr(),
1565                                               Dst.isVolatileQualified());
1566  Store->setAlignment(Dst.getAlignment().getQuantity());
1567}
1568
1569// setObjCGCLValueClass - sets class of he lvalue for the purpose of
1570// generating write-barries API. It is currently a global, ivar,
1571// or neither.
1572static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
1573                                 LValue &LV,
1574                                 bool IsMemberAccess=false) {
1575  if (Ctx.getLangOpts().getGC() == LangOptions::NonGC)
1576    return;
1577
1578  if (isa<ObjCIvarRefExpr>(E)) {
1579    QualType ExpTy = E->getType();
1580    if (IsMemberAccess && ExpTy->isPointerType()) {
1581      // If ivar is a structure pointer, assigning to field of
1582      // this struct follows gcc's behavior and makes it a non-ivar
1583      // writer-barrier conservatively.
1584      ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1585      if (ExpTy->isRecordType()) {
1586        LV.setObjCIvar(false);
1587        return;
1588      }
1589    }
1590    LV.setObjCIvar(true);
1591    ObjCIvarRefExpr *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr*>(E));
1592    LV.setBaseIvarExp(Exp->getBase());
1593    LV.setObjCArray(E->getType()->isArrayType());
1594    return;
1595  }
1596
1597  if (const DeclRefExpr *Exp = dyn_cast<DeclRefExpr>(E)) {
1598    if (const VarDecl *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
1599      if (VD->hasGlobalStorage()) {
1600        LV.setGlobalObjCRef(true);
1601        LV.setThreadLocalRef(VD->getTLSKind() != VarDecl::TLS_None);
1602      }
1603    }
1604    LV.setObjCArray(E->getType()->isArrayType());
1605    return;
1606  }
1607
1608  if (const UnaryOperator *Exp = dyn_cast<UnaryOperator>(E)) {
1609    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1610    return;
1611  }
1612
1613  if (const ParenExpr *Exp = dyn_cast<ParenExpr>(E)) {
1614    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1615    if (LV.isObjCIvar()) {
1616      // If cast is to a structure pointer, follow gcc's behavior and make it
1617      // a non-ivar write-barrier.
1618      QualType ExpTy = E->getType();
1619      if (ExpTy->isPointerType())
1620        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
1621      if (ExpTy->isRecordType())
1622        LV.setObjCIvar(false);
1623    }
1624    return;
1625  }
1626
1627  if (const GenericSelectionExpr *Exp = dyn_cast<GenericSelectionExpr>(E)) {
1628    setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
1629    return;
1630  }
1631
1632  if (const ImplicitCastExpr *Exp = dyn_cast<ImplicitCastExpr>(E)) {
1633    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1634    return;
1635  }
1636
1637  if (const CStyleCastExpr *Exp = dyn_cast<CStyleCastExpr>(E)) {
1638    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1639    return;
1640  }
1641
1642  if (const ObjCBridgedCastExpr *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
1643    setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
1644    return;
1645  }
1646
1647  if (const ArraySubscriptExpr *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
1648    setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
1649    if (LV.isObjCIvar() && !LV.isObjCArray())
1650      // Using array syntax to assigning to what an ivar points to is not
1651      // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
1652      LV.setObjCIvar(false);
1653    else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
1654      // Using array syntax to assigning to what global points to is not
1655      // same as assigning to the global itself. {id *G;} G[i] = 0;
1656      LV.setGlobalObjCRef(false);
1657    return;
1658  }
1659
1660  if (const MemberExpr *Exp = dyn_cast<MemberExpr>(E)) {
1661    setObjCGCLValueClass(Ctx, Exp->getBase(), LV, true);
1662    // We don't know if member is an 'ivar', but this flag is looked at
1663    // only in the context of LV.isObjCIvar().
1664    LV.setObjCArray(E->getType()->isArrayType());
1665    return;
1666  }
1667}
1668
1669static llvm::Value *
1670EmitBitCastOfLValueToProperType(CodeGenFunction &CGF,
1671                                llvm::Value *V, llvm::Type *IRType,
1672                                StringRef Name = StringRef()) {
1673  unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
1674  return CGF.Builder.CreateBitCast(V, IRType->getPointerTo(AS), Name);
1675}
1676
1677static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
1678                                      const Expr *E, const VarDecl *VD) {
1679  llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
1680  llvm::Type *RealVarTy = CGF.getTypes().ConvertTypeForMem(VD->getType());
1681  V = EmitBitCastOfLValueToProperType(CGF, V, RealVarTy);
1682  CharUnits Alignment = CGF.getContext().getDeclAlign(VD);
1683  QualType T = E->getType();
1684  LValue LV;
1685  if (VD->getType()->isReferenceType()) {
1686    llvm::LoadInst *LI = CGF.Builder.CreateLoad(V);
1687    LI->setAlignment(Alignment.getQuantity());
1688    V = LI;
1689    LV = CGF.MakeNaturalAlignAddrLValue(V, T);
1690  } else {
1691    LV = CGF.MakeAddrLValue(V, E->getType(), Alignment);
1692  }
1693  setObjCGCLValueClass(CGF.getContext(), E, LV);
1694  return LV;
1695}
1696
1697static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
1698                                     const Expr *E, const FunctionDecl *FD) {
1699  llvm::Value *V = CGF.CGM.GetAddrOfFunction(FD);
1700  if (!FD->hasPrototype()) {
1701    if (const FunctionProtoType *Proto =
1702            FD->getType()->getAs<FunctionProtoType>()) {
1703      // Ugly case: for a K&R-style definition, the type of the definition
1704      // isn't the same as the type of a use.  Correct for this with a
1705      // bitcast.
1706      QualType NoProtoType =
1707          CGF.getContext().getFunctionNoProtoType(Proto->getResultType());
1708      NoProtoType = CGF.getContext().getPointerType(NoProtoType);
1709      V = CGF.Builder.CreateBitCast(V, CGF.ConvertType(NoProtoType));
1710    }
1711  }
1712  CharUnits Alignment = CGF.getContext().getDeclAlign(FD);
1713  return CGF.MakeAddrLValue(V, E->getType(), Alignment);
1714}
1715
1716static LValue EmitCapturedFieldLValue(CodeGenFunction &CGF, const FieldDecl *FD,
1717                                      llvm::Value *ThisValue) {
1718  QualType TagType = CGF.getContext().getTagDeclType(FD->getParent());
1719  LValue LV = CGF.MakeNaturalAlignAddrLValue(ThisValue, TagType);
1720  return CGF.EmitLValueForField(LV, FD);
1721}
1722
1723LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
1724  const NamedDecl *ND = E->getDecl();
1725  CharUnits Alignment = getContext().getDeclAlign(ND);
1726  QualType T = E->getType();
1727
1728  // A DeclRefExpr for a reference initialized by a constant expression can
1729  // appear without being odr-used. Directly emit the constant initializer.
1730  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1731    const Expr *Init = VD->getAnyInitializer(VD);
1732    if (Init && !isa<ParmVarDecl>(VD) && VD->getType()->isReferenceType() &&
1733        VD->isUsableInConstantExpressions(getContext()) &&
1734        VD->checkInitIsICE()) {
1735      llvm::Constant *Val =
1736        CGM.EmitConstantValue(*VD->evaluateValue(), VD->getType(), this);
1737      assert(Val && "failed to emit reference constant expression");
1738      // FIXME: Eventually we will want to emit vector element references.
1739      return MakeAddrLValue(Val, T, Alignment);
1740    }
1741  }
1742
1743  // FIXME: We should be able to assert this for FunctionDecls as well!
1744  // FIXME: We should be able to assert this for all DeclRefExprs, not just
1745  // those with a valid source location.
1746  assert((ND->isUsed(false) || !isa<VarDecl>(ND) ||
1747          !E->getLocation().isValid()) &&
1748         "Should not use decl without marking it used!");
1749
1750  if (ND->hasAttr<WeakRefAttr>()) {
1751    const ValueDecl *VD = cast<ValueDecl>(ND);
1752    llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
1753    return MakeAddrLValue(Aliasee, T, Alignment);
1754  }
1755
1756  if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
1757    // Check if this is a global variable.
1758    if (VD->hasLinkage() || VD->isStaticDataMember()) {
1759      // If it's thread_local, emit a call to its wrapper function instead.
1760      if (VD->getTLSKind() == VarDecl::TLS_Dynamic)
1761        return CGM.getCXXABI().EmitThreadLocalDeclRefExpr(*this, E);
1762      return EmitGlobalVarDeclLValue(*this, E, VD);
1763    }
1764
1765    bool isBlockVariable = VD->hasAttr<BlocksAttr>();
1766
1767    llvm::Value *V = LocalDeclMap.lookup(VD);
1768    if (!V && VD->isStaticLocal())
1769      V = CGM.getStaticLocalDeclAddress(VD);
1770
1771    // Use special handling for lambdas.
1772    if (!V) {
1773      if (FieldDecl *FD = LambdaCaptureFields.lookup(VD)) {
1774        return EmitCapturedFieldLValue(*this, FD, CXXABIThisValue);
1775      } else if (CapturedStmtInfo) {
1776        if (const FieldDecl *FD = CapturedStmtInfo->lookup(VD))
1777          return EmitCapturedFieldLValue(*this, FD,
1778                                         CapturedStmtInfo->getContextValue());
1779      }
1780
1781      assert(isa<BlockDecl>(CurCodeDecl) && E->refersToEnclosingLocal());
1782      return MakeAddrLValue(GetAddrOfBlockDecl(VD, isBlockVariable),
1783                            T, Alignment);
1784    }
1785
1786    assert(V && "DeclRefExpr not entered in LocalDeclMap?");
1787
1788    if (isBlockVariable)
1789      V = BuildBlockByrefAddress(V, VD);
1790
1791    LValue LV;
1792    if (VD->getType()->isReferenceType()) {
1793      llvm::LoadInst *LI = Builder.CreateLoad(V);
1794      LI->setAlignment(Alignment.getQuantity());
1795      V = LI;
1796      LV = MakeNaturalAlignAddrLValue(V, T);
1797    } else {
1798      LV = MakeAddrLValue(V, T, Alignment);
1799    }
1800
1801    bool isLocalStorage = VD->hasLocalStorage();
1802
1803    bool NonGCable = isLocalStorage &&
1804                     !VD->getType()->isReferenceType() &&
1805                     !isBlockVariable;
1806    if (NonGCable) {
1807      LV.getQuals().removeObjCGCAttr();
1808      LV.setNonGC(true);
1809    }
1810
1811    bool isImpreciseLifetime =
1812      (isLocalStorage && !VD->hasAttr<ObjCPreciseLifetimeAttr>());
1813    if (isImpreciseLifetime)
1814      LV.setARCPreciseLifetime(ARCImpreciseLifetime);
1815    setObjCGCLValueClass(getContext(), E, LV);
1816    return LV;
1817  }
1818
1819  if (const FunctionDecl *fn = dyn_cast<FunctionDecl>(ND))
1820    return EmitFunctionDeclLValue(*this, E, fn);
1821
1822  llvm_unreachable("Unhandled DeclRefExpr");
1823}
1824
1825LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
1826  // __extension__ doesn't affect lvalue-ness.
1827  if (E->getOpcode() == UO_Extension)
1828    return EmitLValue(E->getSubExpr());
1829
1830  QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
1831  switch (E->getOpcode()) {
1832  default: llvm_unreachable("Unknown unary operator lvalue!");
1833  case UO_Deref: {
1834    QualType T = E->getSubExpr()->getType()->getPointeeType();
1835    assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
1836
1837    LValue LV = MakeNaturalAlignAddrLValue(EmitScalarExpr(E->getSubExpr()), T);
1838    LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
1839
1840    // We should not generate __weak write barrier on indirect reference
1841    // of a pointer to object; as in void foo (__weak id *param); *param = 0;
1842    // But, we continue to generate __strong write barrier on indirect write
1843    // into a pointer to object.
1844    if (getLangOpts().ObjC1 &&
1845        getLangOpts().getGC() != LangOptions::NonGC &&
1846        LV.isObjCWeak())
1847      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
1848    return LV;
1849  }
1850  case UO_Real:
1851  case UO_Imag: {
1852    LValue LV = EmitLValue(E->getSubExpr());
1853    assert(LV.isSimple() && "real/imag on non-ordinary l-value");
1854    llvm::Value *Addr = LV.getAddress();
1855
1856    // __real is valid on scalars.  This is a faster way of testing that.
1857    // __imag can only produce an rvalue on scalars.
1858    if (E->getOpcode() == UO_Real &&
1859        !cast<llvm::PointerType>(Addr->getType())
1860           ->getElementType()->isStructTy()) {
1861      assert(E->getSubExpr()->getType()->isArithmeticType());
1862      return LV;
1863    }
1864
1865    assert(E->getSubExpr()->getType()->isAnyComplexType());
1866
1867    unsigned Idx = E->getOpcode() == UO_Imag;
1868    return MakeAddrLValue(Builder.CreateStructGEP(LV.getAddress(),
1869                                                  Idx, "idx"),
1870                          ExprTy);
1871  }
1872  case UO_PreInc:
1873  case UO_PreDec: {
1874    LValue LV = EmitLValue(E->getSubExpr());
1875    bool isInc = E->getOpcode() == UO_PreInc;
1876
1877    if (E->getType()->isAnyComplexType())
1878      EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
1879    else
1880      EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
1881    return LV;
1882  }
1883  }
1884}
1885
1886LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
1887  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
1888                        E->getType());
1889}
1890
1891LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
1892  return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
1893                        E->getType());
1894}
1895
1896static llvm::Constant*
1897GetAddrOfConstantWideString(StringRef Str,
1898                            const char *GlobalName,
1899                            ASTContext &Context,
1900                            QualType Ty, SourceLocation Loc,
1901                            CodeGenModule &CGM) {
1902
1903  StringLiteral *SL = StringLiteral::Create(Context,
1904                                            Str,
1905                                            StringLiteral::Wide,
1906                                            /*Pascal = */false,
1907                                            Ty, Loc);
1908  llvm::Constant *C = CGM.GetConstantArrayFromStringLiteral(SL);
1909  llvm::GlobalVariable *GV =
1910    new llvm::GlobalVariable(CGM.getModule(), C->getType(),
1911                             !CGM.getLangOpts().WritableStrings,
1912                             llvm::GlobalValue::PrivateLinkage,
1913                             C, GlobalName);
1914  const unsigned WideAlignment =
1915    Context.getTypeAlignInChars(Ty).getQuantity();
1916  GV->setAlignment(WideAlignment);
1917  return GV;
1918}
1919
1920static void ConvertUTF8ToWideString(unsigned CharByteWidth, StringRef Source,
1921                                    SmallString<32>& Target) {
1922  Target.resize(CharByteWidth * (Source.size() + 1));
1923  char *ResultPtr = &Target[0];
1924  const UTF8 *ErrorPtr;
1925  bool success = ConvertUTF8toWide(CharByteWidth, Source, ResultPtr, ErrorPtr);
1926  (void)success;
1927  assert(success);
1928  Target.resize(ResultPtr - &Target[0]);
1929}
1930
1931LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
1932  switch (E->getIdentType()) {
1933  default:
1934    return EmitUnsupportedLValue(E, "predefined expression");
1935
1936  case PredefinedExpr::Func:
1937  case PredefinedExpr::Function:
1938  case PredefinedExpr::LFunction:
1939  case PredefinedExpr::PrettyFunction: {
1940    unsigned IdentType = E->getIdentType();
1941    std::string GlobalVarName;
1942
1943    switch (IdentType) {
1944    default: llvm_unreachable("Invalid type");
1945    case PredefinedExpr::Func:
1946      GlobalVarName = "__func__.";
1947      break;
1948    case PredefinedExpr::Function:
1949      GlobalVarName = "__FUNCTION__.";
1950      break;
1951    case PredefinedExpr::LFunction:
1952      GlobalVarName = "L__FUNCTION__.";
1953      break;
1954    case PredefinedExpr::PrettyFunction:
1955      GlobalVarName = "__PRETTY_FUNCTION__.";
1956      break;
1957    }
1958
1959    StringRef FnName = CurFn->getName();
1960    if (FnName.startswith("\01"))
1961      FnName = FnName.substr(1);
1962    GlobalVarName += FnName;
1963
1964    const Decl *CurDecl = CurCodeDecl;
1965    if (CurDecl == 0)
1966      CurDecl = getContext().getTranslationUnitDecl();
1967
1968    std::string FunctionName =
1969        (isa<BlockDecl>(CurDecl)
1970         ? FnName.str()
1971         : PredefinedExpr::ComputeName((PredefinedExpr::IdentType)IdentType,
1972                                       CurDecl));
1973
1974    const Type* ElemType = E->getType()->getArrayElementTypeNoTypeQual();
1975    llvm::Constant *C;
1976    if (ElemType->isWideCharType()) {
1977      SmallString<32> RawChars;
1978      ConvertUTF8ToWideString(
1979          getContext().getTypeSizeInChars(ElemType).getQuantity(),
1980          FunctionName, RawChars);
1981      C = GetAddrOfConstantWideString(RawChars,
1982                                      GlobalVarName.c_str(),
1983                                      getContext(),
1984                                      E->getType(),
1985                                      E->getLocation(),
1986                                      CGM);
1987    } else {
1988      C = CGM.GetAddrOfConstantCString(FunctionName,
1989                                       GlobalVarName.c_str(),
1990                                       1);
1991    }
1992    return MakeAddrLValue(C, E->getType());
1993  }
1994  }
1995}
1996
1997/// Emit a type description suitable for use by a runtime sanitizer library. The
1998/// format of a type descriptor is
1999///
2000/// \code
2001///   { i16 TypeKind, i16 TypeInfo }
2002/// \endcode
2003///
2004/// followed by an array of i8 containing the type name. TypeKind is 0 for an
2005/// integer, 1 for a floating point value, and -1 for anything else.
2006llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) {
2007  // FIXME: Only emit each type's descriptor once.
2008  uint16_t TypeKind = -1;
2009  uint16_t TypeInfo = 0;
2010
2011  if (T->isIntegerType()) {
2012    TypeKind = 0;
2013    TypeInfo = (llvm::Log2_32(getContext().getTypeSize(T)) << 1) |
2014               (T->isSignedIntegerType() ? 1 : 0);
2015  } else if (T->isFloatingType()) {
2016    TypeKind = 1;
2017    TypeInfo = getContext().getTypeSize(T);
2018  }
2019
2020  // Format the type name as if for a diagnostic, including quotes and
2021  // optionally an 'aka'.
2022  SmallString<32> Buffer;
2023  CGM.getDiags().ConvertArgToString(DiagnosticsEngine::ak_qualtype,
2024                                    (intptr_t)T.getAsOpaquePtr(),
2025                                    0, 0, 0, 0, 0, 0, Buffer,
2026                                    ArrayRef<intptr_t>());
2027
2028  llvm::Constant *Components[] = {
2029    Builder.getInt16(TypeKind), Builder.getInt16(TypeInfo),
2030    llvm::ConstantDataArray::getString(getLLVMContext(), Buffer)
2031  };
2032  llvm::Constant *Descriptor = llvm::ConstantStruct::getAnon(Components);
2033
2034  llvm::GlobalVariable *GV =
2035    new llvm::GlobalVariable(CGM.getModule(), Descriptor->getType(),
2036                             /*isConstant=*/true,
2037                             llvm::GlobalVariable::PrivateLinkage,
2038                             Descriptor);
2039  GV->setUnnamedAddr(true);
2040  return GV;
2041}
2042
2043llvm::Value *CodeGenFunction::EmitCheckValue(llvm::Value *V) {
2044  llvm::Type *TargetTy = IntPtrTy;
2045
2046  // Floating-point types which fit into intptr_t are bitcast to integers
2047  // and then passed directly (after zero-extension, if necessary).
2048  if (V->getType()->isFloatingPointTy()) {
2049    unsigned Bits = V->getType()->getPrimitiveSizeInBits();
2050    if (Bits <= TargetTy->getIntegerBitWidth())
2051      V = Builder.CreateBitCast(V, llvm::Type::getIntNTy(getLLVMContext(),
2052                                                         Bits));
2053  }
2054
2055  // Integers which fit in intptr_t are zero-extended and passed directly.
2056  if (V->getType()->isIntegerTy() &&
2057      V->getType()->getIntegerBitWidth() <= TargetTy->getIntegerBitWidth())
2058    return Builder.CreateZExt(V, TargetTy);
2059
2060  // Pointers are passed directly, everything else is passed by address.
2061  if (!V->getType()->isPointerTy()) {
2062    llvm::Value *Ptr = CreateTempAlloca(V->getType());
2063    Builder.CreateStore(V, Ptr);
2064    V = Ptr;
2065  }
2066  return Builder.CreatePtrToInt(V, TargetTy);
2067}
2068
2069/// \brief Emit a representation of a SourceLocation for passing to a handler
2070/// in a sanitizer runtime library. The format for this data is:
2071/// \code
2072///   struct SourceLocation {
2073///     const char *Filename;
2074///     int32_t Line, Column;
2075///   };
2076/// \endcode
2077/// For an invalid SourceLocation, the Filename pointer is null.
2078llvm::Constant *CodeGenFunction::EmitCheckSourceLocation(SourceLocation Loc) {
2079  PresumedLoc PLoc = getContext().getSourceManager().getPresumedLoc(Loc);
2080
2081  llvm::Constant *Data[] = {
2082    // FIXME: Only emit each file name once.
2083    PLoc.isValid() ? cast<llvm::Constant>(
2084                       Builder.CreateGlobalStringPtr(PLoc.getFilename()))
2085                   : llvm::Constant::getNullValue(Int8PtrTy),
2086    Builder.getInt32(PLoc.getLine()),
2087    Builder.getInt32(PLoc.getColumn())
2088  };
2089
2090  return llvm::ConstantStruct::getAnon(Data);
2091}
2092
2093void CodeGenFunction::EmitCheck(llvm::Value *Checked, StringRef CheckName,
2094                                ArrayRef<llvm::Constant *> StaticArgs,
2095                                ArrayRef<llvm::Value *> DynamicArgs,
2096                                CheckRecoverableKind RecoverKind) {
2097  assert(SanOpts != &SanitizerOptions::Disabled);
2098
2099  if (CGM.getCodeGenOpts().SanitizeUndefinedTrapOnError) {
2100    assert (RecoverKind != CRK_AlwaysRecoverable &&
2101            "Runtime call required for AlwaysRecoverable kind!");
2102    return EmitTrapCheck(Checked);
2103  }
2104
2105  llvm::BasicBlock *Cont = createBasicBlock("cont");
2106
2107  llvm::BasicBlock *Handler = createBasicBlock("handler." + CheckName);
2108
2109  llvm::Instruction *Branch = Builder.CreateCondBr(Checked, Cont, Handler);
2110
2111  // Give hint that we very much don't expect to execute the handler
2112  // Value chosen to match UR_NONTAKEN_WEIGHT, see BranchProbabilityInfo.cpp
2113  llvm::MDBuilder MDHelper(getLLVMContext());
2114  llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1);
2115  Branch->setMetadata(llvm::LLVMContext::MD_prof, Node);
2116
2117  EmitBlock(Handler);
2118
2119  llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
2120  llvm::GlobalValue *InfoPtr =
2121      new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false,
2122                               llvm::GlobalVariable::PrivateLinkage, Info);
2123  InfoPtr->setUnnamedAddr(true);
2124
2125  SmallVector<llvm::Value *, 4> Args;
2126  SmallVector<llvm::Type *, 4> ArgTypes;
2127  Args.reserve(DynamicArgs.size() + 1);
2128  ArgTypes.reserve(DynamicArgs.size() + 1);
2129
2130  // Handler functions take an i8* pointing to the (handler-specific) static
2131  // information block, followed by a sequence of intptr_t arguments
2132  // representing operand values.
2133  Args.push_back(Builder.CreateBitCast(InfoPtr, Int8PtrTy));
2134  ArgTypes.push_back(Int8PtrTy);
2135  for (size_t i = 0, n = DynamicArgs.size(); i != n; ++i) {
2136    Args.push_back(EmitCheckValue(DynamicArgs[i]));
2137    ArgTypes.push_back(IntPtrTy);
2138  }
2139
2140  bool Recover = (RecoverKind == CRK_AlwaysRecoverable) ||
2141                 ((RecoverKind == CRK_Recoverable) &&
2142                   CGM.getCodeGenOpts().SanitizeRecover);
2143
2144  llvm::FunctionType *FnType =
2145    llvm::FunctionType::get(CGM.VoidTy, ArgTypes, false);
2146  llvm::AttrBuilder B;
2147  if (!Recover) {
2148    B.addAttribute(llvm::Attribute::NoReturn)
2149     .addAttribute(llvm::Attribute::NoUnwind);
2150  }
2151  B.addAttribute(llvm::Attribute::UWTable);
2152
2153  // Checks that have two variants use a suffix to differentiate them
2154  bool NeedsAbortSuffix = (RecoverKind != CRK_Unrecoverable) &&
2155                           !CGM.getCodeGenOpts().SanitizeRecover;
2156  std::string FunctionName = ("__ubsan_handle_" + CheckName +
2157                              (NeedsAbortSuffix? "_abort" : "")).str();
2158  llvm::Value *Fn =
2159    CGM.CreateRuntimeFunction(FnType, FunctionName,
2160                              llvm::AttributeSet::get(getLLVMContext(),
2161                                              llvm::AttributeSet::FunctionIndex,
2162                                                      B));
2163  llvm::CallInst *HandlerCall = EmitNounwindRuntimeCall(Fn, Args);
2164  if (Recover) {
2165    Builder.CreateBr(Cont);
2166  } else {
2167    HandlerCall->setDoesNotReturn();
2168    Builder.CreateUnreachable();
2169  }
2170
2171  EmitBlock(Cont);
2172}
2173
2174void CodeGenFunction::EmitTrapCheck(llvm::Value *Checked) {
2175  llvm::BasicBlock *Cont = createBasicBlock("cont");
2176
2177  // If we're optimizing, collapse all calls to trap down to just one per
2178  // function to save on code size.
2179  if (!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
2180    TrapBB = createBasicBlock("trap");
2181    Builder.CreateCondBr(Checked, Cont, TrapBB);
2182    EmitBlock(TrapBB);
2183    llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::trap);
2184    llvm::CallInst *TrapCall = Builder.CreateCall(F);
2185    TrapCall->setDoesNotReturn();
2186    TrapCall->setDoesNotThrow();
2187    Builder.CreateUnreachable();
2188  } else {
2189    Builder.CreateCondBr(Checked, Cont, TrapBB);
2190  }
2191
2192  EmitBlock(Cont);
2193}
2194
2195/// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
2196/// array to pointer, return the array subexpression.
2197static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
2198  // If this isn't just an array->pointer decay, bail out.
2199  const CastExpr *CE = dyn_cast<CastExpr>(E);
2200  if (CE == 0 || CE->getCastKind() != CK_ArrayToPointerDecay)
2201    return 0;
2202
2203  // If this is a decay from variable width array, bail out.
2204  const Expr *SubExpr = CE->getSubExpr();
2205  if (SubExpr->getType()->isVariableArrayType())
2206    return 0;
2207
2208  return SubExpr;
2209}
2210
2211LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E,
2212                                               bool Accessed) {
2213  // The index must always be an integer, which is not an aggregate.  Emit it.
2214  llvm::Value *Idx = EmitScalarExpr(E->getIdx());
2215  QualType IdxTy  = E->getIdx()->getType();
2216  bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
2217
2218  if (SanOpts->Bounds)
2219    EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, Accessed);
2220
2221  // If the base is a vector type, then we are forming a vector element lvalue
2222  // with this subscript.
2223  if (E->getBase()->getType()->isVectorType()) {
2224    // Emit the vector as an lvalue to get its address.
2225    LValue LHS = EmitLValue(E->getBase());
2226    assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
2227    Idx = Builder.CreateIntCast(Idx, Int32Ty, IdxSigned, "vidx");
2228    return LValue::MakeVectorElt(LHS.getAddress(), Idx,
2229                                 E->getBase()->getType(), LHS.getAlignment());
2230  }
2231
2232  // Extend or truncate the index type to 32 or 64-bits.
2233  if (Idx->getType() != IntPtrTy)
2234    Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
2235
2236  // We know that the pointer points to a type of the correct size, unless the
2237  // size is a VLA or Objective-C interface.
2238  llvm::Value *Address = 0;
2239  CharUnits ArrayAlignment;
2240  if (const VariableArrayType *vla =
2241        getContext().getAsVariableArrayType(E->getType())) {
2242    // The base must be a pointer, which is not an aggregate.  Emit
2243    // it.  It needs to be emitted first in case it's what captures
2244    // the VLA bounds.
2245    Address = EmitScalarExpr(E->getBase());
2246
2247    // The element count here is the total number of non-VLA elements.
2248    llvm::Value *numElements = getVLASize(vla).first;
2249
2250    // Effectively, the multiply by the VLA size is part of the GEP.
2251    // GEP indexes are signed, and scaling an index isn't permitted to
2252    // signed-overflow, so we use the same semantics for our explicit
2253    // multiply.  We suppress this if overflow is not undefined behavior.
2254    if (getLangOpts().isSignedOverflowDefined()) {
2255      Idx = Builder.CreateMul(Idx, numElements);
2256      Address = Builder.CreateGEP(Address, Idx, "arrayidx");
2257    } else {
2258      Idx = Builder.CreateNSWMul(Idx, numElements);
2259      Address = Builder.CreateInBoundsGEP(Address, Idx, "arrayidx");
2260    }
2261  } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
2262    // Indexing over an interface, as in "NSString *P; P[4];"
2263    llvm::Value *InterfaceSize =
2264      llvm::ConstantInt::get(Idx->getType(),
2265          getContext().getTypeSizeInChars(OIT).getQuantity());
2266
2267    Idx = Builder.CreateMul(Idx, InterfaceSize);
2268
2269    // The base must be a pointer, which is not an aggregate.  Emit it.
2270    llvm::Value *Base = EmitScalarExpr(E->getBase());
2271    Address = EmitCastToVoidPtr(Base);
2272    Address = Builder.CreateGEP(Address, Idx, "arrayidx");
2273    Address = Builder.CreateBitCast(Address, Base->getType());
2274  } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
2275    // If this is A[i] where A is an array, the frontend will have decayed the
2276    // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
2277    // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
2278    // "gep x, i" here.  Emit one "gep A, 0, i".
2279    assert(Array->getType()->isArrayType() &&
2280           "Array to pointer decay must have array source type!");
2281    LValue ArrayLV;
2282    // For simple multidimensional array indexing, set the 'accessed' flag for
2283    // better bounds-checking of the base expression.
2284    if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(Array))
2285      ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true);
2286    else
2287      ArrayLV = EmitLValue(Array);
2288    llvm::Value *ArrayPtr = ArrayLV.getAddress();
2289    llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
2290    llvm::Value *Args[] = { Zero, Idx };
2291
2292    // Propagate the alignment from the array itself to the result.
2293    ArrayAlignment = ArrayLV.getAlignment();
2294
2295    if (getLangOpts().isSignedOverflowDefined())
2296      Address = Builder.CreateGEP(ArrayPtr, Args, "arrayidx");
2297    else
2298      Address = Builder.CreateInBoundsGEP(ArrayPtr, Args, "arrayidx");
2299  } else {
2300    // The base must be a pointer, which is not an aggregate.  Emit it.
2301    llvm::Value *Base = EmitScalarExpr(E->getBase());
2302    if (getLangOpts().isSignedOverflowDefined())
2303      Address = Builder.CreateGEP(Base, Idx, "arrayidx");
2304    else
2305      Address = Builder.CreateInBoundsGEP(Base, Idx, "arrayidx");
2306  }
2307
2308  QualType T = E->getBase()->getType()->getPointeeType();
2309  assert(!T.isNull() &&
2310         "CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
2311
2312
2313  // Limit the alignment to that of the result type.
2314  LValue LV;
2315  if (!ArrayAlignment.isZero()) {
2316    CharUnits Align = getContext().getTypeAlignInChars(T);
2317    ArrayAlignment = std::min(Align, ArrayAlignment);
2318    LV = MakeAddrLValue(Address, T, ArrayAlignment);
2319  } else {
2320    LV = MakeNaturalAlignAddrLValue(Address, T);
2321  }
2322
2323  LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
2324
2325  if (getLangOpts().ObjC1 &&
2326      getLangOpts().getGC() != LangOptions::NonGC) {
2327    LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
2328    setObjCGCLValueClass(getContext(), E, LV);
2329  }
2330  return LV;
2331}
2332
2333static
2334llvm::Constant *GenerateConstantVector(CGBuilderTy &Builder,
2335                                       SmallVectorImpl<unsigned> &Elts) {
2336  SmallVector<llvm::Constant*, 4> CElts;
2337  for (unsigned i = 0, e = Elts.size(); i != e; ++i)
2338    CElts.push_back(Builder.getInt32(Elts[i]));
2339
2340  return llvm::ConstantVector::get(CElts);
2341}
2342
2343LValue CodeGenFunction::
2344EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
2345  // Emit the base vector as an l-value.
2346  LValue Base;
2347
2348  // ExtVectorElementExpr's base can either be a vector or pointer to vector.
2349  if (E->isArrow()) {
2350    // If it is a pointer to a vector, emit the address and form an lvalue with
2351    // it.
2352    llvm::Value *Ptr = EmitScalarExpr(E->getBase());
2353    const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
2354    Base = MakeAddrLValue(Ptr, PT->getPointeeType());
2355    Base.getQuals().removeObjCGCAttr();
2356  } else if (E->getBase()->isGLValue()) {
2357    // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
2358    // emit the base as an lvalue.
2359    assert(E->getBase()->getType()->isVectorType());
2360    Base = EmitLValue(E->getBase());
2361  } else {
2362    // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
2363    assert(E->getBase()->getType()->isVectorType() &&
2364           "Result must be a vector");
2365    llvm::Value *Vec = EmitScalarExpr(E->getBase());
2366
2367    // Store the vector to memory (because LValue wants an address).
2368    llvm::Value *VecMem = CreateMemTemp(E->getBase()->getType());
2369    Builder.CreateStore(Vec, VecMem);
2370    Base = MakeAddrLValue(VecMem, E->getBase()->getType());
2371  }
2372
2373  QualType type =
2374    E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers());
2375
2376  // Encode the element access list into a vector of unsigned indices.
2377  SmallVector<unsigned, 4> Indices;
2378  E->getEncodedElementAccess(Indices);
2379
2380  if (Base.isSimple()) {
2381    llvm::Constant *CV = GenerateConstantVector(Builder, Indices);
2382    return LValue::MakeExtVectorElt(Base.getAddress(), CV, type,
2383                                    Base.getAlignment());
2384  }
2385  assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
2386
2387  llvm::Constant *BaseElts = Base.getExtVectorElts();
2388  SmallVector<llvm::Constant *, 4> CElts;
2389
2390  for (unsigned i = 0, e = Indices.size(); i != e; ++i)
2391    CElts.push_back(BaseElts->getAggregateElement(Indices[i]));
2392  llvm::Constant *CV = llvm::ConstantVector::get(CElts);
2393  return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV, type,
2394                                  Base.getAlignment());
2395}
2396
2397LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
2398  Expr *BaseExpr = E->getBase();
2399
2400  // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
2401  LValue BaseLV;
2402  if (E->isArrow()) {
2403    llvm::Value *Ptr = EmitScalarExpr(BaseExpr);
2404    QualType PtrTy = BaseExpr->getType()->getPointeeType();
2405    EmitTypeCheck(TCK_MemberAccess, E->getExprLoc(), Ptr, PtrTy);
2406    BaseLV = MakeNaturalAlignAddrLValue(Ptr, PtrTy);
2407  } else
2408    BaseLV = EmitCheckedLValue(BaseExpr, TCK_MemberAccess);
2409
2410  NamedDecl *ND = E->getMemberDecl();
2411  if (FieldDecl *Field = dyn_cast<FieldDecl>(ND)) {
2412    LValue LV = EmitLValueForField(BaseLV, Field);
2413    setObjCGCLValueClass(getContext(), E, LV);
2414    return LV;
2415  }
2416
2417  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
2418    return EmitGlobalVarDeclLValue(*this, E, VD);
2419
2420  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
2421    return EmitFunctionDeclLValue(*this, E, FD);
2422
2423  llvm_unreachable("Unhandled member declaration!");
2424}
2425
2426/// Given that we are currently emitting a lambda, emit an l-value for
2427/// one of its members.
2428LValue CodeGenFunction::EmitLValueForLambdaField(const FieldDecl *Field) {
2429  assert(cast<CXXMethodDecl>(CurCodeDecl)->getParent()->isLambda());
2430  assert(cast<CXXMethodDecl>(CurCodeDecl)->getParent() == Field->getParent());
2431  QualType LambdaTagType =
2432    getContext().getTagDeclType(Field->getParent());
2433  LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue, LambdaTagType);
2434  return EmitLValueForField(LambdaLV, Field);
2435}
2436
2437LValue CodeGenFunction::EmitLValueForField(LValue base,
2438                                           const FieldDecl *field) {
2439  if (field->isBitField()) {
2440    const CGRecordLayout &RL =
2441      CGM.getTypes().getCGRecordLayout(field->getParent());
2442    const CGBitFieldInfo &Info = RL.getBitFieldInfo(field);
2443    llvm::Value *Addr = base.getAddress();
2444    unsigned Idx = RL.getLLVMFieldNo(field);
2445    if (Idx != 0)
2446      // For structs, we GEP to the field that the record layout suggests.
2447      Addr = Builder.CreateStructGEP(Addr, Idx, field->getName());
2448    // Get the access type.
2449    llvm::Type *PtrTy = llvm::Type::getIntNPtrTy(
2450      getLLVMContext(), Info.StorageSize,
2451      CGM.getContext().getTargetAddressSpace(base.getType()));
2452    if (Addr->getType() != PtrTy)
2453      Addr = Builder.CreateBitCast(Addr, PtrTy);
2454
2455    QualType fieldType =
2456      field->getType().withCVRQualifiers(base.getVRQualifiers());
2457    return LValue::MakeBitfield(Addr, Info, fieldType, base.getAlignment());
2458  }
2459
2460  const RecordDecl *rec = field->getParent();
2461  QualType type = field->getType();
2462  CharUnits alignment = getContext().getDeclAlign(field);
2463
2464  // FIXME: It should be impossible to have an LValue without alignment for a
2465  // complete type.
2466  if (!base.getAlignment().isZero())
2467    alignment = std::min(alignment, base.getAlignment());
2468
2469  bool mayAlias = rec->hasAttr<MayAliasAttr>();
2470
2471  llvm::Value *addr = base.getAddress();
2472  unsigned cvr = base.getVRQualifiers();
2473  bool TBAAPath = CGM.getCodeGenOpts().StructPathTBAA;
2474  if (rec->isUnion()) {
2475    // For unions, there is no pointer adjustment.
2476    assert(!type->isReferenceType() && "union has reference member");
2477    // TODO: handle path-aware TBAA for union.
2478    TBAAPath = false;
2479  } else {
2480    // For structs, we GEP to the field that the record layout suggests.
2481    unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
2482    addr = Builder.CreateStructGEP(addr, idx, field->getName());
2483
2484    // If this is a reference field, load the reference right now.
2485    if (const ReferenceType *refType = type->getAs<ReferenceType>()) {
2486      llvm::LoadInst *load = Builder.CreateLoad(addr, "ref");
2487      if (cvr & Qualifiers::Volatile) load->setVolatile(true);
2488      load->setAlignment(alignment.getQuantity());
2489
2490      // Loading the reference will disable path-aware TBAA.
2491      TBAAPath = false;
2492      if (CGM.shouldUseTBAA()) {
2493        llvm::MDNode *tbaa;
2494        if (mayAlias)
2495          tbaa = CGM.getTBAAInfo(getContext().CharTy);
2496        else
2497          tbaa = CGM.getTBAAInfo(type);
2498        CGM.DecorateInstruction(load, tbaa);
2499      }
2500
2501      addr = load;
2502      mayAlias = false;
2503      type = refType->getPointeeType();
2504      if (type->isIncompleteType())
2505        alignment = CharUnits();
2506      else
2507        alignment = getContext().getTypeAlignInChars(type);
2508      cvr = 0; // qualifiers don't recursively apply to referencee
2509    }
2510  }
2511
2512  // Make sure that the address is pointing to the right type.  This is critical
2513  // for both unions and structs.  A union needs a bitcast, a struct element
2514  // will need a bitcast if the LLVM type laid out doesn't match the desired
2515  // type.
2516  addr = EmitBitCastOfLValueToProperType(*this, addr,
2517                                         CGM.getTypes().ConvertTypeForMem(type),
2518                                         field->getName());
2519
2520  if (field->hasAttr<AnnotateAttr>())
2521    addr = EmitFieldAnnotations(field, addr);
2522
2523  LValue LV = MakeAddrLValue(addr, type, alignment);
2524  LV.getQuals().addCVRQualifiers(cvr);
2525  if (TBAAPath) {
2526    const ASTRecordLayout &Layout =
2527        getContext().getASTRecordLayout(field->getParent());
2528    // Set the base type to be the base type of the base LValue and
2529    // update offset to be relative to the base type.
2530    LV.setTBAABaseType(mayAlias ? getContext().CharTy : base.getTBAABaseType());
2531    LV.setTBAAOffset(mayAlias ? 0 : base.getTBAAOffset() +
2532                     Layout.getFieldOffset(field->getFieldIndex()) /
2533                                           getContext().getCharWidth());
2534  }
2535
2536  // __weak attribute on a field is ignored.
2537  if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
2538    LV.getQuals().removeObjCGCAttr();
2539
2540  // Fields of may_alias structs act like 'char' for TBAA purposes.
2541  // FIXME: this should get propagated down through anonymous structs
2542  // and unions.
2543  if (mayAlias && LV.getTBAAInfo())
2544    LV.setTBAAInfo(CGM.getTBAAInfo(getContext().CharTy));
2545
2546  return LV;
2547}
2548
2549LValue
2550CodeGenFunction::EmitLValueForFieldInitialization(LValue Base,
2551                                                  const FieldDecl *Field) {
2552  QualType FieldType = Field->getType();
2553
2554  if (!FieldType->isReferenceType())
2555    return EmitLValueForField(Base, Field);
2556
2557  const CGRecordLayout &RL =
2558    CGM.getTypes().getCGRecordLayout(Field->getParent());
2559  unsigned idx = RL.getLLVMFieldNo(Field);
2560  llvm::Value *V = Builder.CreateStructGEP(Base.getAddress(), idx);
2561  assert(!FieldType.getObjCGCAttr() && "fields cannot have GC attrs");
2562
2563  // Make sure that the address is pointing to the right type.  This is critical
2564  // for both unions and structs.  A union needs a bitcast, a struct element
2565  // will need a bitcast if the LLVM type laid out doesn't match the desired
2566  // type.
2567  llvm::Type *llvmType = ConvertTypeForMem(FieldType);
2568  V = EmitBitCastOfLValueToProperType(*this, V, llvmType, Field->getName());
2569
2570  CharUnits Alignment = getContext().getDeclAlign(Field);
2571
2572  // FIXME: It should be impossible to have an LValue without alignment for a
2573  // complete type.
2574  if (!Base.getAlignment().isZero())
2575    Alignment = std::min(Alignment, Base.getAlignment());
2576
2577  return MakeAddrLValue(V, FieldType, Alignment);
2578}
2579
2580LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
2581  if (E->isFileScope()) {
2582    llvm::Value *GlobalPtr = CGM.GetAddrOfConstantCompoundLiteral(E);
2583    return MakeAddrLValue(GlobalPtr, E->getType());
2584  }
2585  if (E->getType()->isVariablyModifiedType())
2586    // make sure to emit the VLA size.
2587    EmitVariablyModifiedType(E->getType());
2588
2589  llvm::Value *DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
2590  const Expr *InitExpr = E->getInitializer();
2591  LValue Result = MakeAddrLValue(DeclPtr, E->getType());
2592
2593  EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
2594                   /*Init*/ true);
2595
2596  return Result;
2597}
2598
2599LValue CodeGenFunction::EmitInitListLValue(const InitListExpr *E) {
2600  if (!E->isGLValue())
2601    // Initializing an aggregate temporary in C++11: T{...}.
2602    return EmitAggExprToLValue(E);
2603
2604  // An lvalue initializer list must be initializing a reference.
2605  assert(E->getNumInits() == 1 && "reference init with multiple values");
2606  return EmitLValue(E->getInit(0));
2607}
2608
2609LValue CodeGenFunction::
2610EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
2611  if (!expr->isGLValue()) {
2612    // ?: here should be an aggregate.
2613    assert(hasAggregateEvaluationKind(expr->getType()) &&
2614           "Unexpected conditional operator!");
2615    return EmitAggExprToLValue(expr);
2616  }
2617
2618  OpaqueValueMapping binding(*this, expr);
2619
2620  const Expr *condExpr = expr->getCond();
2621  bool CondExprBool;
2622  if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
2623    const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr();
2624    if (!CondExprBool) std::swap(live, dead);
2625
2626    if (!ContainsLabel(dead))
2627      return EmitLValue(live);
2628  }
2629
2630  llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
2631  llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
2632  llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
2633
2634  ConditionalEvaluation eval(*this);
2635  EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock);
2636
2637  // Any temporaries created here are conditional.
2638  EmitBlock(lhsBlock);
2639  eval.begin(*this);
2640  LValue lhs = EmitLValue(expr->getTrueExpr());
2641  eval.end(*this);
2642
2643  if (!lhs.isSimple())
2644    return EmitUnsupportedLValue(expr, "conditional operator");
2645
2646  lhsBlock = Builder.GetInsertBlock();
2647  Builder.CreateBr(contBlock);
2648
2649  // Any temporaries created here are conditional.
2650  EmitBlock(rhsBlock);
2651  eval.begin(*this);
2652  LValue rhs = EmitLValue(expr->getFalseExpr());
2653  eval.end(*this);
2654  if (!rhs.isSimple())
2655    return EmitUnsupportedLValue(expr, "conditional operator");
2656  rhsBlock = Builder.GetInsertBlock();
2657
2658  EmitBlock(contBlock);
2659
2660  llvm::PHINode *phi = Builder.CreatePHI(lhs.getAddress()->getType(), 2,
2661                                         "cond-lvalue");
2662  phi->addIncoming(lhs.getAddress(), lhsBlock);
2663  phi->addIncoming(rhs.getAddress(), rhsBlock);
2664  return MakeAddrLValue(phi, expr->getType());
2665}
2666
2667/// EmitCastLValue - Casts are never lvalues unless that cast is to a reference
2668/// type. If the cast is to a reference, we can have the usual lvalue result,
2669/// otherwise if a cast is needed by the code generator in an lvalue context,
2670/// then it must mean that we need the address of an aggregate in order to
2671/// access one of its members.  This can happen for all the reasons that casts
2672/// are permitted with aggregate result, including noop aggregate casts, and
2673/// cast from scalar to union.
2674LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
2675  switch (E->getCastKind()) {
2676  case CK_ToVoid:
2677  case CK_BitCast:
2678  case CK_ArrayToPointerDecay:
2679  case CK_FunctionToPointerDecay:
2680  case CK_NullToMemberPointer:
2681  case CK_NullToPointer:
2682  case CK_IntegralToPointer:
2683  case CK_PointerToIntegral:
2684  case CK_PointerToBoolean:
2685  case CK_VectorSplat:
2686  case CK_IntegralCast:
2687  case CK_IntegralToBoolean:
2688  case CK_IntegralToFloating:
2689  case CK_FloatingToIntegral:
2690  case CK_FloatingToBoolean:
2691  case CK_FloatingCast:
2692  case CK_FloatingRealToComplex:
2693  case CK_FloatingComplexToReal:
2694  case CK_FloatingComplexToBoolean:
2695  case CK_FloatingComplexCast:
2696  case CK_FloatingComplexToIntegralComplex:
2697  case CK_IntegralRealToComplex:
2698  case CK_IntegralComplexToReal:
2699  case CK_IntegralComplexToBoolean:
2700  case CK_IntegralComplexCast:
2701  case CK_IntegralComplexToFloatingComplex:
2702  case CK_DerivedToBaseMemberPointer:
2703  case CK_BaseToDerivedMemberPointer:
2704  case CK_MemberPointerToBoolean:
2705  case CK_ReinterpretMemberPointer:
2706  case CK_AnyPointerToBlockPointerCast:
2707  case CK_ARCProduceObject:
2708  case CK_ARCConsumeObject:
2709  case CK_ARCReclaimReturnedObject:
2710  case CK_ARCExtendBlockObject:
2711  case CK_CopyAndAutoreleaseBlockObject:
2712    return EmitUnsupportedLValue(E, "unexpected cast lvalue");
2713
2714  case CK_Dependent:
2715    llvm_unreachable("dependent cast kind in IR gen!");
2716
2717  case CK_BuiltinFnToFnPtr:
2718    llvm_unreachable("builtin functions are handled elsewhere");
2719
2720  // These are never l-values; just use the aggregate emission code.
2721  case CK_NonAtomicToAtomic:
2722  case CK_AtomicToNonAtomic:
2723    return EmitAggExprToLValue(E);
2724
2725  case CK_Dynamic: {
2726    LValue LV = EmitLValue(E->getSubExpr());
2727    llvm::Value *V = LV.getAddress();
2728    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(E);
2729    return MakeAddrLValue(EmitDynamicCast(V, DCE), E->getType());
2730  }
2731
2732  case CK_ConstructorConversion:
2733  case CK_UserDefinedConversion:
2734  case CK_CPointerToObjCPointerCast:
2735  case CK_BlockPointerToObjCPointerCast:
2736  case CK_NoOp:
2737  case CK_LValueToRValue:
2738    return EmitLValue(E->getSubExpr());
2739
2740  case CK_UncheckedDerivedToBase:
2741  case CK_DerivedToBase: {
2742    const RecordType *DerivedClassTy =
2743      E->getSubExpr()->getType()->getAs<RecordType>();
2744    CXXRecordDecl *DerivedClassDecl =
2745      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2746
2747    LValue LV = EmitLValue(E->getSubExpr());
2748    llvm::Value *This = LV.getAddress();
2749
2750    // Perform the derived-to-base conversion
2751    llvm::Value *Base =
2752      GetAddressOfBaseClass(This, DerivedClassDecl,
2753                            E->path_begin(), E->path_end(),
2754                            /*NullCheckValue=*/false);
2755
2756    return MakeAddrLValue(Base, E->getType());
2757  }
2758  case CK_ToUnion:
2759    return EmitAggExprToLValue(E);
2760  case CK_BaseToDerived: {
2761    const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
2762    CXXRecordDecl *DerivedClassDecl =
2763      cast<CXXRecordDecl>(DerivedClassTy->getDecl());
2764
2765    LValue LV = EmitLValue(E->getSubExpr());
2766
2767    // C++11 [expr.static.cast]p2: Behavior is undefined if a downcast is
2768    // performed and the object is not of the derived type.
2769    if (SanitizePerformTypeCheck)
2770      EmitTypeCheck(TCK_DowncastReference, E->getExprLoc(),
2771                    LV.getAddress(), E->getType());
2772
2773    // Perform the base-to-derived conversion
2774    llvm::Value *Derived =
2775      GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
2776                               E->path_begin(), E->path_end(),
2777                               /*NullCheckValue=*/false);
2778
2779    return MakeAddrLValue(Derived, E->getType());
2780  }
2781  case CK_LValueBitCast: {
2782    // This must be a reinterpret_cast (or c-style equivalent).
2783    const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
2784
2785    LValue LV = EmitLValue(E->getSubExpr());
2786    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2787                                           ConvertType(CE->getTypeAsWritten()));
2788    return MakeAddrLValue(V, E->getType());
2789  }
2790  case CK_ObjCObjectLValueCast: {
2791    LValue LV = EmitLValue(E->getSubExpr());
2792    QualType ToType = getContext().getLValueReferenceType(E->getType());
2793    llvm::Value *V = Builder.CreateBitCast(LV.getAddress(),
2794                                           ConvertType(ToType));
2795    return MakeAddrLValue(V, E->getType());
2796  }
2797  case CK_ZeroToOCLEvent:
2798    llvm_unreachable("NULL to OpenCL event lvalue cast is not valid");
2799  }
2800
2801  llvm_unreachable("Unhandled lvalue cast kind?");
2802}
2803
2804LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
2805  assert(OpaqueValueMappingData::shouldBindAsLValue(e));
2806  return getOpaqueLValueMapping(e);
2807}
2808
2809RValue CodeGenFunction::EmitRValueForField(LValue LV,
2810                                           const FieldDecl *FD) {
2811  QualType FT = FD->getType();
2812  LValue FieldLV = EmitLValueForField(LV, FD);
2813  switch (getEvaluationKind(FT)) {
2814  case TEK_Complex:
2815    return RValue::getComplex(EmitLoadOfComplex(FieldLV));
2816  case TEK_Aggregate:
2817    return FieldLV.asAggregateRValue();
2818  case TEK_Scalar:
2819    return EmitLoadOfLValue(FieldLV);
2820  }
2821  llvm_unreachable("bad evaluation kind");
2822}
2823
2824//===--------------------------------------------------------------------===//
2825//                             Expression Emission
2826//===--------------------------------------------------------------------===//
2827
2828RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
2829                                     ReturnValueSlot ReturnValue) {
2830  if (CGDebugInfo *DI = getDebugInfo()) {
2831    SourceLocation Loc = E->getLocStart();
2832    // Force column info to be generated so we can differentiate
2833    // multiple call sites on the same line in the debug info.
2834    const FunctionDecl* Callee = E->getDirectCallee();
2835    bool ForceColumnInfo = Callee && Callee->isInlineSpecified();
2836    DI->EmitLocation(Builder, Loc, ForceColumnInfo);
2837  }
2838
2839  // Builtins never have block type.
2840  if (E->getCallee()->getType()->isBlockPointerType())
2841    return EmitBlockCallExpr(E, ReturnValue);
2842
2843  if (const CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(E))
2844    return EmitCXXMemberCallExpr(CE, ReturnValue);
2845
2846  if (const CUDAKernelCallExpr *CE = dyn_cast<CUDAKernelCallExpr>(E))
2847    return EmitCUDAKernelCallExpr(CE, ReturnValue);
2848
2849  const Decl *TargetDecl = E->getCalleeDecl();
2850  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl)) {
2851    if (unsigned builtinID = FD->getBuiltinID())
2852      return EmitBuiltinExpr(FD, builtinID, E);
2853  }
2854
2855  if (const CXXOperatorCallExpr *CE = dyn_cast<CXXOperatorCallExpr>(E))
2856    if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
2857      return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
2858
2859  if (const CXXPseudoDestructorExpr *PseudoDtor
2860          = dyn_cast<CXXPseudoDestructorExpr>(E->getCallee()->IgnoreParens())) {
2861    QualType DestroyedType = PseudoDtor->getDestroyedType();
2862    if (getLangOpts().ObjCAutoRefCount &&
2863        DestroyedType->isObjCLifetimeType() &&
2864        (DestroyedType.getObjCLifetime() == Qualifiers::OCL_Strong ||
2865         DestroyedType.getObjCLifetime() == Qualifiers::OCL_Weak)) {
2866      // Automatic Reference Counting:
2867      //   If the pseudo-expression names a retainable object with weak or
2868      //   strong lifetime, the object shall be released.
2869      Expr *BaseExpr = PseudoDtor->getBase();
2870      llvm::Value *BaseValue = NULL;
2871      Qualifiers BaseQuals;
2872
2873      // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
2874      if (PseudoDtor->isArrow()) {
2875        BaseValue = EmitScalarExpr(BaseExpr);
2876        const PointerType *PTy = BaseExpr->getType()->getAs<PointerType>();
2877        BaseQuals = PTy->getPointeeType().getQualifiers();
2878      } else {
2879        LValue BaseLV = EmitLValue(BaseExpr);
2880        BaseValue = BaseLV.getAddress();
2881        QualType BaseTy = BaseExpr->getType();
2882        BaseQuals = BaseTy.getQualifiers();
2883      }
2884
2885      switch (PseudoDtor->getDestroyedType().getObjCLifetime()) {
2886      case Qualifiers::OCL_None:
2887      case Qualifiers::OCL_ExplicitNone:
2888      case Qualifiers::OCL_Autoreleasing:
2889        break;
2890
2891      case Qualifiers::OCL_Strong:
2892        EmitARCRelease(Builder.CreateLoad(BaseValue,
2893                          PseudoDtor->getDestroyedType().isVolatileQualified()),
2894                       ARCPreciseLifetime);
2895        break;
2896
2897      case Qualifiers::OCL_Weak:
2898        EmitARCDestroyWeak(BaseValue);
2899        break;
2900      }
2901    } else {
2902      // C++ [expr.pseudo]p1:
2903      //   The result shall only be used as the operand for the function call
2904      //   operator (), and the result of such a call has type void. The only
2905      //   effect is the evaluation of the postfix-expression before the dot or
2906      //   arrow.
2907      EmitScalarExpr(E->getCallee());
2908    }
2909
2910    return RValue::get(0);
2911  }
2912
2913  llvm::Value *Callee = EmitScalarExpr(E->getCallee());
2914  return EmitCall(E->getCallee()->getType(), Callee, ReturnValue,
2915                  E->arg_begin(), E->arg_end(), TargetDecl);
2916}
2917
2918LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
2919  // Comma expressions just emit their LHS then their RHS as an l-value.
2920  if (E->getOpcode() == BO_Comma) {
2921    EmitIgnoredExpr(E->getLHS());
2922    EnsureInsertPoint();
2923    return EmitLValue(E->getRHS());
2924  }
2925
2926  if (E->getOpcode() == BO_PtrMemD ||
2927      E->getOpcode() == BO_PtrMemI)
2928    return EmitPointerToDataMemberBinaryExpr(E);
2929
2930  assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
2931
2932  // Note that in all of these cases, __block variables need the RHS
2933  // evaluated first just in case the variable gets moved by the RHS.
2934
2935  switch (getEvaluationKind(E->getType())) {
2936  case TEK_Scalar: {
2937    switch (E->getLHS()->getType().getObjCLifetime()) {
2938    case Qualifiers::OCL_Strong:
2939      return EmitARCStoreStrong(E, /*ignored*/ false).first;
2940
2941    case Qualifiers::OCL_Autoreleasing:
2942      return EmitARCStoreAutoreleasing(E).first;
2943
2944    // No reason to do any of these differently.
2945    case Qualifiers::OCL_None:
2946    case Qualifiers::OCL_ExplicitNone:
2947    case Qualifiers::OCL_Weak:
2948      break;
2949    }
2950
2951    RValue RV = EmitAnyExpr(E->getRHS());
2952    LValue LV = EmitCheckedLValue(E->getLHS(), TCK_Store);
2953    EmitStoreThroughLValue(RV, LV);
2954    return LV;
2955  }
2956
2957  case TEK_Complex:
2958    return EmitComplexAssignmentLValue(E);
2959
2960  case TEK_Aggregate:
2961    return EmitAggExprToLValue(E);
2962  }
2963  llvm_unreachable("bad evaluation kind");
2964}
2965
2966LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
2967  RValue RV = EmitCallExpr(E);
2968
2969  if (!RV.isScalar())
2970    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
2971
2972  assert(E->getCallReturnType()->isReferenceType() &&
2973         "Can't have a scalar return unless the return type is a "
2974         "reference type!");
2975
2976  return MakeAddrLValue(RV.getScalarVal(), E->getType());
2977}
2978
2979LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
2980  // FIXME: This shouldn't require another copy.
2981  return EmitAggExprToLValue(E);
2982}
2983
2984LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
2985  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
2986         && "binding l-value to type which needs a temporary");
2987  AggValueSlot Slot = CreateAggTemp(E->getType());
2988  EmitCXXConstructExpr(E, Slot);
2989  return MakeAddrLValue(Slot.getAddr(), E->getType());
2990}
2991
2992LValue
2993CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
2994  return MakeAddrLValue(EmitCXXTypeidExpr(E), E->getType());
2995}
2996
2997llvm::Value *CodeGenFunction::EmitCXXUuidofExpr(const CXXUuidofExpr *E) {
2998  return CGM.GetAddrOfUuidDescriptor(E);
2999}
3000
3001LValue CodeGenFunction::EmitCXXUuidofLValue(const CXXUuidofExpr *E) {
3002  return MakeAddrLValue(EmitCXXUuidofExpr(E), E->getType());
3003}
3004
3005LValue
3006CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
3007  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
3008  Slot.setExternallyDestructed();
3009  EmitAggExpr(E->getSubExpr(), Slot);
3010  EmitCXXTemporary(E->getTemporary(), E->getType(), Slot.getAddr());
3011  return MakeAddrLValue(Slot.getAddr(), E->getType());
3012}
3013
3014LValue
3015CodeGenFunction::EmitLambdaLValue(const LambdaExpr *E) {
3016  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
3017  EmitLambdaExpr(E, Slot);
3018  return MakeAddrLValue(Slot.getAddr(), E->getType());
3019}
3020
3021LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
3022  RValue RV = EmitObjCMessageExpr(E);
3023
3024  if (!RV.isScalar())
3025    return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
3026
3027  assert(E->getMethodDecl()->getResultType()->isReferenceType() &&
3028         "Can't have a scalar return unless the return type is a "
3029         "reference type!");
3030
3031  return MakeAddrLValue(RV.getScalarVal(), E->getType());
3032}
3033
3034LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
3035  llvm::Value *V =
3036    CGM.getObjCRuntime().GetSelector(*this, E->getSelector(), true);
3037  return MakeAddrLValue(V, E->getType());
3038}
3039
3040llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
3041                                             const ObjCIvarDecl *Ivar) {
3042  return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
3043}
3044
3045LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
3046                                          llvm::Value *BaseValue,
3047                                          const ObjCIvarDecl *Ivar,
3048                                          unsigned CVRQualifiers) {
3049  return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
3050                                                   Ivar, CVRQualifiers);
3051}
3052
3053LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
3054  // FIXME: A lot of the code below could be shared with EmitMemberExpr.
3055  llvm::Value *BaseValue = 0;
3056  const Expr *BaseExpr = E->getBase();
3057  Qualifiers BaseQuals;
3058  QualType ObjectTy;
3059  if (E->isArrow()) {
3060    BaseValue = EmitScalarExpr(BaseExpr);
3061    ObjectTy = BaseExpr->getType()->getPointeeType();
3062    BaseQuals = ObjectTy.getQualifiers();
3063  } else {
3064    LValue BaseLV = EmitLValue(BaseExpr);
3065    // FIXME: this isn't right for bitfields.
3066    BaseValue = BaseLV.getAddress();
3067    ObjectTy = BaseExpr->getType();
3068    BaseQuals = ObjectTy.getQualifiers();
3069  }
3070
3071  LValue LV =
3072    EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
3073                      BaseQuals.getCVRQualifiers());
3074  setObjCGCLValueClass(getContext(), E, LV);
3075  return LV;
3076}
3077
3078LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
3079  // Can only get l-value for message expression returning aggregate type
3080  RValue RV = EmitAnyExprToTemp(E);
3081  return MakeAddrLValue(RV.getAggregateAddr(), E->getType());
3082}
3083
3084RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
3085                                 ReturnValueSlot ReturnValue,
3086                                 CallExpr::const_arg_iterator ArgBeg,
3087                                 CallExpr::const_arg_iterator ArgEnd,
3088                                 const Decl *TargetDecl) {
3089  // Get the actual function type. The callee type will always be a pointer to
3090  // function type or a block pointer type.
3091  assert(CalleeType->isFunctionPointerType() &&
3092         "Call must have function pointer type!");
3093
3094  CalleeType = getContext().getCanonicalType(CalleeType);
3095
3096  const FunctionType *FnType
3097    = cast<FunctionType>(cast<PointerType>(CalleeType)->getPointeeType());
3098
3099  // Force column info to differentiate multiple inlined call sites on
3100  // the same line, analoguous to EmitCallExpr.
3101  bool ForceColumnInfo = false;
3102  if (const FunctionDecl* FD = dyn_cast_or_null<const FunctionDecl>(TargetDecl))
3103    ForceColumnInfo = FD->isInlineSpecified();
3104
3105  CallArgList Args;
3106  EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), ArgBeg, ArgEnd,
3107               ForceColumnInfo);
3108
3109  const CGFunctionInfo &FnInfo =
3110    CGM.getTypes().arrangeFreeFunctionCall(Args, FnType);
3111
3112  // C99 6.5.2.2p6:
3113  //   If the expression that denotes the called function has a type
3114  //   that does not include a prototype, [the default argument
3115  //   promotions are performed]. If the number of arguments does not
3116  //   equal the number of parameters, the behavior is undefined. If
3117  //   the function is defined with a type that includes a prototype,
3118  //   and either the prototype ends with an ellipsis (, ...) or the
3119  //   types of the arguments after promotion are not compatible with
3120  //   the types of the parameters, the behavior is undefined. If the
3121  //   function is defined with a type that does not include a
3122  //   prototype, and the types of the arguments after promotion are
3123  //   not compatible with those of the parameters after promotion,
3124  //   the behavior is undefined [except in some trivial cases].
3125  // That is, in the general case, we should assume that a call
3126  // through an unprototyped function type works like a *non-variadic*
3127  // call.  The way we make this work is to cast to the exact type
3128  // of the promoted arguments.
3129  if (isa<FunctionNoProtoType>(FnType)) {
3130    llvm::Type *CalleeTy = getTypes().GetFunctionType(FnInfo);
3131    CalleeTy = CalleeTy->getPointerTo();
3132    Callee = Builder.CreateBitCast(Callee, CalleeTy, "callee.knr.cast");
3133  }
3134
3135  return EmitCall(FnInfo, Callee, ReturnValue, Args, TargetDecl);
3136}
3137
3138LValue CodeGenFunction::
3139EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
3140  llvm::Value *BaseV;
3141  if (E->getOpcode() == BO_PtrMemI)
3142    BaseV = EmitScalarExpr(E->getLHS());
3143  else
3144    BaseV = EmitLValue(E->getLHS()).getAddress();
3145
3146  llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
3147
3148  const MemberPointerType *MPT
3149    = E->getRHS()->getType()->getAs<MemberPointerType>();
3150
3151  llvm::Value *AddV =
3152    CGM.getCXXABI().EmitMemberDataPointerAddress(*this, BaseV, OffsetV, MPT);
3153
3154  return MakeAddrLValue(AddV, MPT->getPointeeType());
3155}
3156
3157/// Given the address of a temporary variable, produce an r-value of
3158/// its type.
3159RValue CodeGenFunction::convertTempToRValue(llvm::Value *addr,
3160                                            QualType type) {
3161  LValue lvalue = MakeNaturalAlignAddrLValue(addr, type);
3162  switch (getEvaluationKind(type)) {
3163  case TEK_Complex:
3164    return RValue::getComplex(EmitLoadOfComplex(lvalue));
3165  case TEK_Aggregate:
3166    return lvalue.asAggregateRValue();
3167  case TEK_Scalar:
3168    return RValue::get(EmitLoadOfScalar(lvalue));
3169  }
3170  llvm_unreachable("bad evaluation kind");
3171}
3172
3173void CodeGenFunction::SetFPAccuracy(llvm::Value *Val, float Accuracy) {
3174  assert(Val->getType()->isFPOrFPVectorTy());
3175  if (Accuracy == 0.0 || !isa<llvm::Instruction>(Val))
3176    return;
3177
3178  llvm::MDBuilder MDHelper(getLLVMContext());
3179  llvm::MDNode *Node = MDHelper.createFPMath(Accuracy);
3180
3181  cast<llvm::Instruction>(Val)->setMetadata(llvm::LLVMContext::MD_fpmath, Node);
3182}
3183
3184namespace {
3185  struct LValueOrRValue {
3186    LValue LV;
3187    RValue RV;
3188  };
3189}
3190
3191static LValueOrRValue emitPseudoObjectExpr(CodeGenFunction &CGF,
3192                                           const PseudoObjectExpr *E,
3193                                           bool forLValue,
3194                                           AggValueSlot slot) {
3195  SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
3196
3197  // Find the result expression, if any.
3198  const Expr *resultExpr = E->getResultExpr();
3199  LValueOrRValue result;
3200
3201  for (PseudoObjectExpr::const_semantics_iterator
3202         i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
3203    const Expr *semantic = *i;
3204
3205    // If this semantic expression is an opaque value, bind it
3206    // to the result of its source expression.
3207    if (const OpaqueValueExpr *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
3208
3209      // If this is the result expression, we may need to evaluate
3210      // directly into the slot.
3211      typedef CodeGenFunction::OpaqueValueMappingData OVMA;
3212      OVMA opaqueData;
3213      if (ov == resultExpr && ov->isRValue() && !forLValue &&
3214          CodeGenFunction::hasAggregateEvaluationKind(ov->getType())) {
3215        CGF.EmitAggExpr(ov->getSourceExpr(), slot);
3216
3217        LValue LV = CGF.MakeAddrLValue(slot.getAddr(), ov->getType());
3218        opaqueData = OVMA::bind(CGF, ov, LV);
3219        result.RV = slot.asRValue();
3220
3221      // Otherwise, emit as normal.
3222      } else {
3223        opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
3224
3225        // If this is the result, also evaluate the result now.
3226        if (ov == resultExpr) {
3227          if (forLValue)
3228            result.LV = CGF.EmitLValue(ov);
3229          else
3230            result.RV = CGF.EmitAnyExpr(ov, slot);
3231        }
3232      }
3233
3234      opaques.push_back(opaqueData);
3235
3236    // Otherwise, if the expression is the result, evaluate it
3237    // and remember the result.
3238    } else if (semantic == resultExpr) {
3239      if (forLValue)
3240        result.LV = CGF.EmitLValue(semantic);
3241      else
3242        result.RV = CGF.EmitAnyExpr(semantic, slot);
3243
3244    // Otherwise, evaluate the expression in an ignored context.
3245    } else {
3246      CGF.EmitIgnoredExpr(semantic);
3247    }
3248  }
3249
3250  // Unbind all the opaques now.
3251  for (unsigned i = 0, e = opaques.size(); i != e; ++i)
3252    opaques[i].unbind(CGF);
3253
3254  return result;
3255}
3256
3257RValue CodeGenFunction::EmitPseudoObjectRValue(const PseudoObjectExpr *E,
3258                                               AggValueSlot slot) {
3259  return emitPseudoObjectExpr(*this, E, false, slot).RV;
3260}
3261
3262LValue CodeGenFunction::EmitPseudoObjectLValue(const PseudoObjectExpr *E) {
3263  return emitPseudoObjectExpr(*this, E, true, AggValueSlot::ignored()).LV;
3264}
3265