/
CGExpr.cpp
3411 lines (2939 loc) · 130 KB
/
CGExpr.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
//===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Expr nodes as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CGCXXABI.h"
#include "CGCall.h"
#include "CGDebugInfo.h"
#include "CGObjCRuntime.h"
#include "CGRecordLayout.h"
#include "CodeGenModule.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Attr.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/Support/ConvertUTF.h"
using namespace clang;
using namespace CodeGen;
//===--------------------------------------------------------------------===//
// Miscellaneous Helper Methods
//===--------------------------------------------------------------------===//
llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
unsigned addressSpace =
cast<llvm::PointerType>(value->getType())->getAddressSpace();
llvm::PointerType *destType = Int8PtrTy;
if (addressSpace)
destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
if (value->getType() == destType) return value;
return Builder.CreateBitCast(value, destType);
}
/// CreateTempAlloca - This creates a alloca and inserts it into the entry
/// block.
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
const Twine &Name) {
if (!Builder.isNamePreserving())
return new llvm::AllocaInst(Ty, nullptr, "", AllocaInsertPt);
return new llvm::AllocaInst(Ty, nullptr, Name, AllocaInsertPt);
}
void CodeGenFunction::InitTempAlloca(llvm::AllocaInst *Var,
llvm::Value *Init) {
auto *Store = new llvm::StoreInst(Init, Var);
llvm::BasicBlock *Block = AllocaInsertPt->getParent();
Block->getInstList().insertAfter(&*AllocaInsertPt, Store);
}
llvm::AllocaInst *CodeGenFunction::CreateIRTemp(QualType Ty,
const Twine &Name) {
llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertType(Ty), Name);
// FIXME: Should we prefer the preferred type alignment here?
CharUnits Align = getContext().getTypeAlignInChars(Ty);
Alloc->setAlignment(Align.getQuantity());
return Alloc;
}
llvm::AllocaInst *CodeGenFunction::CreateMemTemp(QualType Ty,
const Twine &Name) {
llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), Name);
// FIXME: Should we prefer the preferred type alignment here?
CharUnits Align = getContext().getTypeAlignInChars(Ty);
Alloc->setAlignment(Align.getQuantity());
return Alloc;
}
/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
/// expression and compare the result against zero, returning an Int1Ty value.
llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
PGO.setCurrentStmt(E);
if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
llvm::Value *MemPtr = EmitScalarExpr(E);
return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT);
}
QualType BoolTy = getContext().BoolTy;
if (!E->getType()->isAnyComplexType())
return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
}
/// EmitIgnoredExpr - Emit code to compute the specified expression,
/// ignoring the result.
void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
if (E->isRValue())
return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
// Just emit it as an l-value and drop the result.
EmitLValue(E);
}
/// EmitAnyExpr - Emit code to compute the specified expression which
/// can have any type. The result is returned as an RValue struct.
/// If this is an aggregate expression, AggSlot indicates where the
/// result should be returned.
RValue CodeGenFunction::EmitAnyExpr(const Expr *E,
AggValueSlot aggSlot,
bool ignoreResult) {
switch (getEvaluationKind(E->getType())) {
case TEK_Scalar:
return RValue::get(EmitScalarExpr(E, ignoreResult));
case TEK_Complex:
return RValue::getComplex(EmitComplexExpr(E, ignoreResult, ignoreResult));
case TEK_Aggregate:
if (!ignoreResult && aggSlot.isIgnored())
aggSlot = CreateAggTemp(E->getType(), "agg-temp");
EmitAggExpr(E, aggSlot);
return aggSlot.asRValue();
}
llvm_unreachable("bad evaluation kind");
}
/// EmitAnyExprToTemp - Similary to EmitAnyExpr(), however, the result will
/// always be accessible even if no aggregate location is provided.
RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
AggValueSlot AggSlot = AggValueSlot::ignored();
if (hasAggregateEvaluationKind(E->getType()))
AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
return EmitAnyExpr(E, AggSlot);
}
/// EmitAnyExprToMem - Evaluate an expression into a given memory
/// location.
void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
llvm::Value *Location,
Qualifiers Quals,
bool IsInit) {
// FIXME: This function should take an LValue as an argument.
switch (getEvaluationKind(E->getType())) {
case TEK_Complex:
EmitComplexExprIntoLValue(E,
MakeNaturalAlignAddrLValue(Location, E->getType()),
/*isInit*/ false);
return;
case TEK_Aggregate: {
CharUnits Alignment = getContext().getTypeAlignInChars(E->getType());
EmitAggExpr(E, AggValueSlot::forAddr(Location, Alignment, Quals,
AggValueSlot::IsDestructed_t(IsInit),
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsAliased_t(!IsInit)));
return;
}
case TEK_Scalar: {
RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
LValue LV = MakeAddrLValue(Location, E->getType());
EmitStoreThroughLValue(RV, LV);
return;
}
}
llvm_unreachable("bad evaluation kind");
}
static void
pushTemporaryCleanup(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M,
const Expr *E, llvm::Value *ReferenceTemporary) {
// Objective-C++ ARC:
// If we are binding a reference to a temporary that has ownership, we
// need to perform retain/release operations on the temporary.
//
// FIXME: This should be looking at E, not M.
if (CGF.getLangOpts().ObjCAutoRefCount &&
M->getType()->isObjCLifetimeType()) {
QualType ObjCARCReferenceLifetimeType = M->getType();
switch (Qualifiers::ObjCLifetime Lifetime =
ObjCARCReferenceLifetimeType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
// Carry on to normal cleanup handling.
break;
case Qualifiers::OCL_Autoreleasing:
// Nothing to do; cleaned up by an autorelease pool.
return;
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Weak:
switch (StorageDuration Duration = M->getStorageDuration()) {
case SD_Static:
// Note: we intentionally do not register a cleanup to release
// the object on program termination.
return;
case SD_Thread:
// FIXME: We should probably register a cleanup in this case.
return;
case SD_Automatic:
case SD_FullExpression:
assert(!ObjCARCReferenceLifetimeType->isArrayType());
CodeGenFunction::Destroyer *Destroy;
CleanupKind CleanupKind;
if (Lifetime == Qualifiers::OCL_Strong) {
const ValueDecl *VD = M->getExtendingDecl();
bool Precise =
VD && isa<VarDecl>(VD) && VD->hasAttr<ObjCPreciseLifetimeAttr>();
CleanupKind = CGF.getARCCleanupKind();
Destroy = Precise ? &CodeGenFunction::destroyARCStrongPrecise
: &CodeGenFunction::destroyARCStrongImprecise;
} else {
// __weak objects always get EH cleanups; otherwise, exceptions
// could cause really nasty crashes instead of mere leaks.
CleanupKind = NormalAndEHCleanup;
Destroy = &CodeGenFunction::destroyARCWeak;
}
if (Duration == SD_FullExpression)
CGF.pushDestroy(CleanupKind, ReferenceTemporary,
ObjCARCReferenceLifetimeType, *Destroy,
CleanupKind & EHCleanup);
else
CGF.pushLifetimeExtendedDestroy(CleanupKind, ReferenceTemporary,
ObjCARCReferenceLifetimeType,
*Destroy, CleanupKind & EHCleanup);
return;
case SD_Dynamic:
llvm_unreachable("temporary cannot have dynamic storage duration");
}
llvm_unreachable("unknown storage duration");
}
}
CXXDestructorDecl *ReferenceTemporaryDtor = nullptr;
if (const RecordType *RT =
E->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
// Get the destructor for the reference temporary.
auto *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
if (!ClassDecl->hasTrivialDestructor())
ReferenceTemporaryDtor = ClassDecl->getDestructor();
}
if (!ReferenceTemporaryDtor)
return;
// Call the destructor for the temporary.
switch (M->getStorageDuration()) {
case SD_Static:
case SD_Thread: {
llvm::Constant *CleanupFn;
llvm::Constant *CleanupArg;
if (E->getType()->isArrayType()) {
CleanupFn = CodeGenFunction(CGF.CGM).generateDestroyHelper(
cast<llvm::Constant>(ReferenceTemporary), E->getType(),
CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions,
dyn_cast_or_null<VarDecl>(M->getExtendingDecl()));
CleanupArg = llvm::Constant::getNullValue(CGF.Int8PtrTy);
} else {
CleanupFn =
CGF.CGM.GetAddrOfCXXDestructor(ReferenceTemporaryDtor, Dtor_Complete);
CleanupArg = cast<llvm::Constant>(ReferenceTemporary);
}
CGF.CGM.getCXXABI().registerGlobalDtor(
CGF, *cast<VarDecl>(M->getExtendingDecl()), CleanupFn, CleanupArg);
break;
}
case SD_FullExpression:
CGF.pushDestroy(NormalAndEHCleanup, ReferenceTemporary, E->getType(),
CodeGenFunction::destroyCXXObject,
CGF.getLangOpts().Exceptions);
break;
case SD_Automatic:
CGF.pushLifetimeExtendedDestroy(NormalAndEHCleanup,
ReferenceTemporary, E->getType(),
CodeGenFunction::destroyCXXObject,
CGF.getLangOpts().Exceptions);
break;
case SD_Dynamic:
llvm_unreachable("temporary cannot have dynamic storage duration");
}
}
static llvm::Value *
createReferenceTemporary(CodeGenFunction &CGF,
const MaterializeTemporaryExpr *M, const Expr *Inner) {
switch (M->getStorageDuration()) {
case SD_FullExpression:
case SD_Automatic:
return CGF.CreateMemTemp(Inner->getType(), "ref.tmp");
case SD_Thread:
case SD_Static:
return CGF.CGM.GetAddrOfGlobalTemporary(M, Inner);
case SD_Dynamic:
llvm_unreachable("temporary can't have dynamic storage duration");
}
llvm_unreachable("unknown storage duration");
}
LValue CodeGenFunction::EmitMaterializeTemporaryExpr(
const MaterializeTemporaryExpr *M) {
const Expr *E = M->GetTemporaryExpr();
if (getLangOpts().ObjCAutoRefCount &&
M->getType()->isObjCLifetimeType() &&
M->getType().getObjCLifetime() != Qualifiers::OCL_None &&
M->getType().getObjCLifetime() != Qualifiers::OCL_ExplicitNone) {
// FIXME: Fold this into the general case below.
llvm::Value *Object = createReferenceTemporary(*this, M, E);
LValue RefTempDst = MakeAddrLValue(Object, M->getType());
if (auto *Var = dyn_cast<llvm::GlobalVariable>(Object)) {
// We should not have emitted the initializer for this temporary as a
// constant.
assert(!Var->hasInitializer());
Var->setInitializer(CGM.EmitNullConstant(E->getType()));
}
EmitScalarInit(E, M->getExtendingDecl(), RefTempDst, false);
pushTemporaryCleanup(*this, M, E, Object);
return RefTempDst;
}
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
EmitIgnoredExpr(CommaLHSs[I]);
if (const auto *opaque = dyn_cast<OpaqueValueExpr>(E)) {
if (opaque->getType()->isRecordType()) {
assert(Adjustments.empty());
return EmitOpaqueValueLValue(opaque);
}
}
// Create and initialize the reference temporary.
llvm::Value *Object = createReferenceTemporary(*this, M, E);
if (auto *Var = dyn_cast<llvm::GlobalVariable>(Object)) {
// If the temporary is a global and has a constant initializer, we may
// have already initialized it.
if (!Var->hasInitializer()) {
Var->setInitializer(CGM.EmitNullConstant(E->getType()));
EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
}
} else {
EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
}
pushTemporaryCleanup(*this, M, E, Object);
// Perform derived-to-base casts and/or field accesses, to get from the
// temporary object we created (and, potentially, for which we extended
// the lifetime) to the subobject we're binding the reference to.
for (unsigned I = Adjustments.size(); I != 0; --I) {
SubobjectAdjustment &Adjustment = Adjustments[I-1];
switch (Adjustment.Kind) {
case SubobjectAdjustment::DerivedToBaseAdjustment:
Object =
GetAddressOfBaseClass(Object, Adjustment.DerivedToBase.DerivedClass,
Adjustment.DerivedToBase.BasePath->path_begin(),
Adjustment.DerivedToBase.BasePath->path_end(),
/*NullCheckValue=*/ false);
break;
case SubobjectAdjustment::FieldAdjustment: {
LValue LV = MakeAddrLValue(Object, E->getType());
LV = EmitLValueForField(LV, Adjustment.Field);
assert(LV.isSimple() &&
"materialized temporary field is not a simple lvalue");
Object = LV.getAddress();
break;
}
case SubobjectAdjustment::MemberPointerAdjustment: {
llvm::Value *Ptr = EmitScalarExpr(Adjustment.Ptr.RHS);
Object = CGM.getCXXABI().EmitMemberDataPointerAddress(
*this, E, Object, Ptr, Adjustment.Ptr.MPT);
break;
}
}
}
return MakeAddrLValue(Object, M->getType());
}
RValue
CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E) {
// Emit the expression as an lvalue.
LValue LV = EmitLValue(E);
assert(LV.isSimple());
llvm::Value *Value = LV.getAddress();
if (SanitizePerformTypeCheck && !E->getType()->isFunctionType()) {
// C++11 [dcl.ref]p5 (as amended by core issue 453):
// If a glvalue to which a reference is directly bound designates neither
// an existing object or function of an appropriate type nor a region of
// storage of suitable size and alignment to contain an object of the
// reference's type, the behavior is undefined.
QualType Ty = E->getType();
EmitTypeCheck(TCK_ReferenceBinding, E->getExprLoc(), Value, Ty);
}
return RValue::get(Value);
}
/// getAccessedFieldNo - Given an encoded value and a result number, return the
/// input field number being accessed.
unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
const llvm::Constant *Elts) {
return cast<llvm::ConstantInt>(Elts->getAggregateElement(Idx))
->getZExtValue();
}
/// Emit the hash_16_bytes function from include/llvm/ADT/Hashing.h.
static llvm::Value *emitHash16Bytes(CGBuilderTy &Builder, llvm::Value *Low,
llvm::Value *High) {
llvm::Value *KMul = Builder.getInt64(0x9ddfea08eb382d69ULL);
llvm::Value *K47 = Builder.getInt64(47);
llvm::Value *A0 = Builder.CreateMul(Builder.CreateXor(Low, High), KMul);
llvm::Value *A1 = Builder.CreateXor(Builder.CreateLShr(A0, K47), A0);
llvm::Value *B0 = Builder.CreateMul(Builder.CreateXor(High, A1), KMul);
llvm::Value *B1 = Builder.CreateXor(Builder.CreateLShr(B0, K47), B0);
return Builder.CreateMul(B1, KMul);
}
void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
llvm::Value *Address,
QualType Ty, CharUnits Alignment) {
if (!SanitizePerformTypeCheck)
return;
// Don't check pointers outside the default address space. The null check
// isn't correct, the object-size check isn't supported by LLVM, and we can't
// communicate the addresses to the runtime handler for the vptr check.
if (Address->getType()->getPointerAddressSpace())
return;
llvm::Value *Cond = nullptr;
llvm::BasicBlock *Done = nullptr;
if (SanOpts->Null) {
// The glvalue must not be an empty glvalue.
Cond = Builder.CreateICmpNE(
Address, llvm::Constant::getNullValue(Address->getType()));
if (TCK == TCK_DowncastPointer) {
// When performing a pointer downcast, it's OK if the value is null.
// Skip the remaining checks in that case.
Done = createBasicBlock("null");
llvm::BasicBlock *Rest = createBasicBlock("not.null");
Builder.CreateCondBr(Cond, Rest, Done);
EmitBlock(Rest);
Cond = nullptr;
}
}
if (SanOpts->ObjectSize && !Ty->isIncompleteType()) {
uint64_t Size = getContext().getTypeSizeInChars(Ty).getQuantity();
// The glvalue must refer to a large enough storage region.
// FIXME: If Address Sanitizer is enabled, insert dynamic instrumentation
// to check this.
// FIXME: Get object address space
llvm::Type *Tys[2] = { IntPtrTy, Int8PtrTy };
llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, Tys);
llvm::Value *Min = Builder.getFalse();
llvm::Value *CastAddr = Builder.CreateBitCast(Address, Int8PtrTy);
llvm::Value *LargeEnough =
Builder.CreateICmpUGE(Builder.CreateCall2(F, CastAddr, Min),
llvm::ConstantInt::get(IntPtrTy, Size));
Cond = Cond ? Builder.CreateAnd(Cond, LargeEnough) : LargeEnough;
}
uint64_t AlignVal = 0;
if (SanOpts->Alignment) {
AlignVal = Alignment.getQuantity();
if (!Ty->isIncompleteType() && !AlignVal)
AlignVal = getContext().getTypeAlignInChars(Ty).getQuantity();
// The glvalue must be suitably aligned.
if (AlignVal) {
llvm::Value *Align =
Builder.CreateAnd(Builder.CreatePtrToInt(Address, IntPtrTy),
llvm::ConstantInt::get(IntPtrTy, AlignVal - 1));
llvm::Value *Aligned =
Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0));
Cond = Cond ? Builder.CreateAnd(Cond, Aligned) : Aligned;
}
}
if (Cond) {
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(Loc),
EmitCheckTypeDescriptor(Ty),
llvm::ConstantInt::get(SizeTy, AlignVal),
llvm::ConstantInt::get(Int8Ty, TCK)
};
EmitCheck(Cond, "type_mismatch", StaticData, Address, CRK_Recoverable);
}
// If possible, check that the vptr indicates that there is a subobject of
// type Ty at offset zero within this object.
//
// C++11 [basic.life]p5,6:
// [For storage which does not refer to an object within its lifetime]
// The program has undefined behavior if:
// -- the [pointer or glvalue] is used to access a non-static data member
// or call a non-static member function
CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
if (SanOpts->Vptr &&
(TCK == TCK_MemberAccess || TCK == TCK_MemberCall ||
TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference) &&
RD && RD->hasDefinition() && RD->isDynamicClass()) {
// Compute a hash of the mangled name of the type.
//
// FIXME: This is not guaranteed to be deterministic! Move to a
// fingerprinting mechanism once LLVM provides one. For the time
// being the implementation happens to be deterministic.
SmallString<64> MangledName;
llvm::raw_svector_ostream Out(MangledName);
CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty.getUnqualifiedType(),
Out);
llvm::hash_code TypeHash = hash_value(Out.str());
// Load the vptr, and compute hash_16_bytes(TypeHash, vptr).
llvm::Value *Low = llvm::ConstantInt::get(Int64Ty, TypeHash);
llvm::Type *VPtrTy = llvm::PointerType::get(IntPtrTy, 0);
llvm::Value *VPtrAddr = Builder.CreateBitCast(Address, VPtrTy);
llvm::Value *VPtrVal = Builder.CreateLoad(VPtrAddr);
llvm::Value *High = Builder.CreateZExt(VPtrVal, Int64Ty);
llvm::Value *Hash = emitHash16Bytes(Builder, Low, High);
Hash = Builder.CreateTrunc(Hash, IntPtrTy);
// Look the hash up in our cache.
const int CacheSize = 128;
llvm::Type *HashTable = llvm::ArrayType::get(IntPtrTy, CacheSize);
llvm::Value *Cache = CGM.CreateRuntimeVariable(HashTable,
"__ubsan_vptr_type_cache");
llvm::Value *Slot = Builder.CreateAnd(Hash,
llvm::ConstantInt::get(IntPtrTy,
CacheSize-1));
llvm::Value *Indices[] = { Builder.getInt32(0), Slot };
llvm::Value *CacheVal =
Builder.CreateLoad(Builder.CreateInBoundsGEP(Cache, Indices));
// If the hash isn't in the cache, call a runtime handler to perform the
// hard work of checking whether the vptr is for an object of the right
// type. This will either fill in the cache and return, or produce a
// diagnostic.
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(Loc),
EmitCheckTypeDescriptor(Ty),
CGM.GetAddrOfRTTIDescriptor(Ty.getUnqualifiedType()),
llvm::ConstantInt::get(Int8Ty, TCK)
};
llvm::Value *DynamicData[] = { Address, Hash };
EmitCheck(Builder.CreateICmpEQ(CacheVal, Hash),
"dynamic_type_cache_miss", StaticData, DynamicData,
CRK_AlwaysRecoverable);
}
if (Done) {
Builder.CreateBr(Done);
EmitBlock(Done);
}
}
/// Determine whether this expression refers to a flexible array member in a
/// struct. We disable array bounds checks for such members.
static bool isFlexibleArrayMemberExpr(const Expr *E) {
// For compatibility with existing code, we treat arrays of length 0 or
// 1 as flexible array members.
const ArrayType *AT = E->getType()->castAsArrayTypeUnsafe();
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
if (CAT->getSize().ugt(1))
return false;
} else if (!isa<IncompleteArrayType>(AT))
return false;
E = E->IgnoreParens();
// A flexible array member must be the last member in the class.
if (const auto *ME = dyn_cast<MemberExpr>(E)) {
// FIXME: If the base type of the member expr is not FD->getParent(),
// this should not be treated as a flexible array member access.
if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
RecordDecl::field_iterator FI(
DeclContext::decl_iterator(const_cast<FieldDecl *>(FD)));
return ++FI == FD->getParent()->field_end();
}
}
return false;
}
/// If Base is known to point to the start of an array, return the length of
/// that array. Return 0 if the length cannot be determined.
static llvm::Value *getArrayIndexingBound(
CodeGenFunction &CGF, const Expr *Base, QualType &IndexedType) {
// For the vector indexing extension, the bound is the number of elements.
if (const VectorType *VT = Base->getType()->getAs<VectorType>()) {
IndexedType = Base->getType();
return CGF.Builder.getInt32(VT->getNumElements());
}
Base = Base->IgnoreParens();
if (const auto *CE = dyn_cast<CastExpr>(Base)) {
if (CE->getCastKind() == CK_ArrayToPointerDecay &&
!isFlexibleArrayMemberExpr(CE->getSubExpr())) {
IndexedType = CE->getSubExpr()->getType();
const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe();
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
return CGF.Builder.getInt(CAT->getSize());
else if (const auto *VAT = dyn_cast<VariableArrayType>(AT))
return CGF.getVLASize(VAT).first;
}
}
return nullptr;
}
void CodeGenFunction::EmitBoundsCheck(const Expr *E, const Expr *Base,
llvm::Value *Index, QualType IndexType,
bool Accessed) {
assert(SanOpts->ArrayBounds &&
"should not be called unless adding bounds checks");
QualType IndexedType;
llvm::Value *Bound = getArrayIndexingBound(*this, Base, IndexedType);
if (!Bound)
return;
bool IndexSigned = IndexType->isSignedIntegerOrEnumerationType();
llvm::Value *IndexVal = Builder.CreateIntCast(Index, SizeTy, IndexSigned);
llvm::Value *BoundVal = Builder.CreateIntCast(Bound, SizeTy, false);
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(E->getExprLoc()),
EmitCheckTypeDescriptor(IndexedType),
EmitCheckTypeDescriptor(IndexType)
};
llvm::Value *Check = Accessed ? Builder.CreateICmpULT(IndexVal, BoundVal)
: Builder.CreateICmpULE(IndexVal, BoundVal);
EmitCheck(Check, "out_of_bounds", StaticData, Index, CRK_Recoverable);
}
CodeGenFunction::ComplexPairTy CodeGenFunction::
EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
bool isInc, bool isPre) {
ComplexPairTy InVal = EmitLoadOfComplex(LV, E->getExprLoc());
llvm::Value *NextVal;
if (isa<llvm::IntegerType>(InVal.first->getType())) {
uint64_t AmountVal = isInc ? 1 : -1;
NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
// Add the inc/dec to the real part.
NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
} else {
QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
if (!isInc)
FVal.changeSign();
NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
// Add the inc/dec to the real part.
NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
}
ComplexPairTy IncVal(NextVal, InVal.second);
// Store the updated result through the lvalue.
EmitStoreOfComplex(IncVal, LV, /*init*/ false);
// If this is a postinc, return the value read from memory, otherwise use the
// updated value.
return isPre ? IncVal : InVal;
}
//===----------------------------------------------------------------------===//
// LValue Expression Emission
//===----------------------------------------------------------------------===//
RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
if (Ty->isVoidType())
return RValue::get(nullptr);
switch (getEvaluationKind(Ty)) {
case TEK_Complex: {
llvm::Type *EltTy =
ConvertType(Ty->castAs<ComplexType>()->getElementType());
llvm::Value *U = llvm::UndefValue::get(EltTy);
return RValue::getComplex(std::make_pair(U, U));
}
// If this is a use of an undefined aggregate type, the aggregate must have an
// identifiable address. Just because the contents of the value are undefined
// doesn't mean that the address can't be taken and compared.
case TEK_Aggregate: {
llvm::Value *DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
return RValue::getAggregate(DestPtr);
}
case TEK_Scalar:
return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
}
llvm_unreachable("bad evaluation kind");
}
RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
const char *Name) {
ErrorUnsupported(E, Name);
return GetUndefRValue(E->getType());
}
LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
const char *Name) {
ErrorUnsupported(E, Name);
llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
return MakeAddrLValue(llvm::UndefValue::get(Ty), E->getType());
}
LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) {
LValue LV;
if (SanOpts->ArrayBounds && isa<ArraySubscriptExpr>(E))
LV = EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E), /*Accessed*/true);
else
LV = EmitLValue(E);
if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple())
EmitTypeCheck(TCK, E->getExprLoc(), LV.getAddress(),
E->getType(), LV.getAlignment());
return LV;
}
/// EmitLValue - Emit code to compute a designator that specifies the location
/// of the expression.
///
/// This can return one of two things: a simple address or a bitfield reference.
/// In either case, the LLVM Value* in the LValue structure is guaranteed to be
/// an LLVM pointer type.
///
/// If this returns a bitfield reference, nothing about the pointee type of the
/// LLVM value is known: For example, it may not be a pointer to an integer.
///
/// If this returns a normal address, and if the lvalue's C type is fixed size,
/// this method guarantees that the returned pointer type will point to an LLVM
/// type of the same size of the lvalue's type. If the lvalue has a variable
/// length type, this is not possible.
///
LValue CodeGenFunction::EmitLValue(const Expr *E) {
switch (E->getStmtClass()) {
default: return EmitUnsupportedLValue(E, "l-value expression");
case Expr::ObjCPropertyRefExprClass:
llvm_unreachable("cannot emit a property reference directly");
case Expr::ObjCSelectorExprClass:
return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
case Expr::ObjCIsaExprClass:
return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
case Expr::BinaryOperatorClass:
return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
case Expr::CompoundAssignOperatorClass:
if (!E->getType()->isAnyComplexType())
return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
case Expr::CallExprClass:
case Expr::CXXMemberCallExprClass:
case Expr::CXXOperatorCallExprClass:
case Expr::UserDefinedLiteralClass:
return EmitCallExprLValue(cast<CallExpr>(E));
case Expr::VAArgExprClass:
return EmitVAArgExprLValue(cast<VAArgExpr>(E));
case Expr::DeclRefExprClass:
return EmitDeclRefLValue(cast<DeclRefExpr>(E));
case Expr::ParenExprClass:
return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
case Expr::GenericSelectionExprClass:
return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
case Expr::PredefinedExprClass:
return EmitPredefinedLValue(cast<PredefinedExpr>(E));
case Expr::StringLiteralClass:
return EmitStringLiteralLValue(cast<StringLiteral>(E));
case Expr::ObjCEncodeExprClass:
return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
case Expr::PseudoObjectExprClass:
return EmitPseudoObjectLValue(cast<PseudoObjectExpr>(E));
case Expr::InitListExprClass:
return EmitInitListLValue(cast<InitListExpr>(E));
case Expr::CXXTemporaryObjectExprClass:
case Expr::CXXConstructExprClass:
return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
case Expr::CXXBindTemporaryExprClass:
return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
case Expr::CXXUuidofExprClass:
return EmitCXXUuidofLValue(cast<CXXUuidofExpr>(E));
case Expr::LambdaExprClass:
return EmitLambdaLValue(cast<LambdaExpr>(E));
case Expr::ExprWithCleanupsClass: {
const auto *cleanups = cast<ExprWithCleanups>(E);
enterFullExpression(cleanups);
RunCleanupsScope Scope(*this);
return EmitLValue(cleanups->getSubExpr());
}
case Expr::CXXDefaultArgExprClass:
return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
case Expr::CXXDefaultInitExprClass: {
CXXDefaultInitExprScope Scope(*this);
return EmitLValue(cast<CXXDefaultInitExpr>(E)->getExpr());
}
case Expr::CXXTypeidExprClass:
return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
case Expr::ObjCMessageExprClass:
return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
case Expr::ObjCIvarRefExprClass:
return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
case Expr::StmtExprClass:
return EmitStmtExprLValue(cast<StmtExpr>(E));
case Expr::UnaryOperatorClass:
return EmitUnaryOpLValue(cast<UnaryOperator>(E));
case Expr::ArraySubscriptExprClass:
return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
case Expr::ExtVectorElementExprClass:
return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
case Expr::MemberExprClass:
return EmitMemberExpr(cast<MemberExpr>(E));
case Expr::CompoundLiteralExprClass:
return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
case Expr::ConditionalOperatorClass:
return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
case Expr::BinaryConditionalOperatorClass:
return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
case Expr::ChooseExprClass:
return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr());
case Expr::OpaqueValueExprClass:
return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
case Expr::SubstNonTypeTemplateParmExprClass:
return EmitLValue(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
case Expr::ImplicitCastExprClass:
case Expr::CStyleCastExprClass:
case Expr::CXXFunctionalCastExprClass:
case Expr::CXXStaticCastExprClass:
case Expr::CXXDynamicCastExprClass:
case Expr::CXXReinterpretCastExprClass:
case Expr::CXXConstCastExprClass:
case Expr::ObjCBridgedCastExprClass:
return EmitCastLValue(cast<CastExpr>(E));
case Expr::MaterializeTemporaryExprClass:
return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
}
}
/// Given an object of the given canonical type, can we safely copy a
/// value out of it based on its initializer?
static bool isConstantEmittableObjectType(QualType type) {
assert(type.isCanonical());
assert(!type->isReferenceType());
// Must be const-qualified but non-volatile.
Qualifiers qs = type.getLocalQualifiers();
if (!qs.hasConst() || qs.hasVolatile()) return false;
// Otherwise, all object types satisfy this except C++ classes with
// mutable subobjects or non-trivial copy/destroy behavior.
if (const auto *RT = dyn_cast<RecordType>(type))
if (const auto *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
if (RD->hasMutableFields() || !RD->isTrivial())
return false;
return true;
}
/// Can we constant-emit a load of a reference to a variable of the
/// given type? This is different from predicates like
/// Decl::isUsableInConstantExpressions because we do want it to apply
/// in situations that don't necessarily satisfy the language's rules
/// for this (e.g. C++'s ODR-use rules). For example, we want to able
/// to do this with const float variables even if those variables
/// aren't marked 'constexpr'.
enum ConstantEmissionKind {
CEK_None,
CEK_AsReferenceOnly,
CEK_AsValueOrReference,
CEK_AsValueOnly
};
static ConstantEmissionKind checkVarTypeForConstantEmission(QualType type) {
type = type.getCanonicalType();
if (const auto *ref = dyn_cast<ReferenceType>(type)) {
if (isConstantEmittableObjectType(ref->getPointeeType()))
return CEK_AsValueOrReference;
return CEK_AsReferenceOnly;
}
if (isConstantEmittableObjectType(type))
return CEK_AsValueOnly;
return CEK_None;
}
/// Try to emit a reference to the given value without producing it as
/// an l-value. This is actually more than an optimization: we can't
/// produce an l-value for variables that we never actually captured
/// in a block or lambda, which means const int variables or constexpr
/// literals or similar.
CodeGenFunction::ConstantEmission
CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
ValueDecl *value = refExpr->getDecl();
// The value needs to be an enum constant or a constant variable.
ConstantEmissionKind CEK;
if (isa<ParmVarDecl>(value)) {
CEK = CEK_None;
} else if (auto *var = dyn_cast<VarDecl>(value)) {
CEK = checkVarTypeForConstantEmission(var->getType());
} else if (isa<EnumConstantDecl>(value)) {
CEK = CEK_AsValueOnly;
} else {
CEK = CEK_None;
}
if (CEK == CEK_None) return ConstantEmission();
Expr::EvalResult result;
bool resultIsReference;
QualType resultType;
// It's best to evaluate all the way as an r-value if that's permitted.
if (CEK != CEK_AsReferenceOnly &&
refExpr->EvaluateAsRValue(result, getContext())) {
resultIsReference = false;
resultType = refExpr->getType();
// Otherwise, try to evaluate as an l-value.
} else if (CEK != CEK_AsValueOnly &&
refExpr->EvaluateAsLValue(result, getContext())) {
resultIsReference = true;
resultType = value->getType();
// Failure.
} else {
return ConstantEmission();
}
// In any case, if the initializer has side-effects, abandon ship.
if (result.HasSideEffects)
return ConstantEmission();
// Emit as a constant.
llvm::Constant *C = CGM.EmitConstantValue(result.Val, resultType, this);
// Make sure we emit a debug reference to the global variable.
// This should probably fire even for
if (isa<VarDecl>(value)) {
if (!getContext().DeclMustBeEmitted(cast<VarDecl>(value)))
EmitDeclRefExprDbgValue(refExpr, C);
} else {
assert(isa<EnumConstantDecl>(value));
EmitDeclRefExprDbgValue(refExpr, C);
}
// If we emitted a reference constant, we need to dereference that.
if (resultIsReference)
return ConstantEmission::forReference(C);
return ConstantEmission::forValue(C);
}
llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue,
SourceLocation Loc) {
return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
lvalue.getAlignment().getQuantity(),
lvalue.getType(), Loc, lvalue.getTBAAInfo(),
lvalue.getTBAABaseType(), lvalue.getTBAAOffset());
}
static bool hasBooleanRepresentation(QualType Ty) {