forked from llvm/llvm-project
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathCGExpr.cpp
6498 lines (5670 loc) · 254 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 ---------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Expr nodes as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "ABIInfoImpl.h"
#include "CGCUDARuntime.h"
#include "CGCXXABI.h"
#include "CGCall.h"
#include "CGCleanup.h"
#include "CGDebugInfo.h"
#include "CGObjCRuntime.h"
#include "CGOpenMPRuntime.h"
#include "CGRecordLayout.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/Attr.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/NSAPI.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/CodeGenOptions.h"
#include "clang/Basic/SourceManager.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/MatrixBuilder.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/xxhash.h"
#include "llvm/Transforms/Utils/SanitizerStats.h"
#include <numeric>
#include <optional>
#include <string>
using namespace clang;
using namespace CodeGen;
namespace clang {
// TODO: Introduce frontend options to enabled per sanitizers, similar to
// `fsanitize-trap`.
llvm::cl::opt<bool> ClSanitizeGuardChecks(
"ubsan-guard-checks", llvm::cl::Optional,
llvm::cl::desc("Guard UBSAN checks with `llvm.allow.ubsan.check()`."));
} // namespace clang
//===--------------------------------------------------------------------===//
// Defines for metadata
//===--------------------------------------------------------------------===//
// Those values are crucial to be the SAME as in ubsan runtime library.
enum VariableTypeDescriptorKind : uint16_t {
/// An integer type.
TK_Integer = 0x0000,
/// A floating-point type.
TK_Float = 0x0001,
/// An _BitInt(N) type.
TK_BitInt = 0x0002,
/// Any other type. The value representation is unspecified.
TK_Unknown = 0xffff
};
//===--------------------------------------------------------------------===//
// Miscellaneous Helper Methods
//===--------------------------------------------------------------------===//
/// CreateTempAlloca - This creates a alloca and inserts it into the entry
/// block.
RawAddress
CodeGenFunction::CreateTempAllocaWithoutCast(llvm::Type *Ty, CharUnits Align,
const Twine &Name,
llvm::Value *ArraySize) {
auto Alloca = CreateTempAlloca(Ty, Name, ArraySize);
Alloca->setAlignment(Align.getAsAlign());
return RawAddress(Alloca, Ty, Align, KnownNonNull);
}
/// CreateTempAlloca - This creates a alloca and inserts it into the entry
/// block. The alloca is casted to default address space if necessary.
RawAddress CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, CharUnits Align,
const Twine &Name,
llvm::Value *ArraySize,
RawAddress *AllocaAddr) {
auto Alloca = CreateTempAllocaWithoutCast(Ty, Align, Name, ArraySize);
if (AllocaAddr)
*AllocaAddr = Alloca;
llvm::Value *V = Alloca.getPointer();
// Alloca always returns a pointer in alloca address space, which may
// be different from the type defined by the language. For example,
// in C++ the auto variables are in the default address space. Therefore
// cast alloca to the default address space when necessary.
if (getASTAllocaAddressSpace() != LangAS::Default) {
auto DestAddrSpace = getContext().getTargetAddressSpace(LangAS::Default);
llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
// When ArraySize is nullptr, alloca is inserted at AllocaInsertPt,
// otherwise alloca is inserted at the current insertion point of the
// builder.
if (!ArraySize)
Builder.SetInsertPoint(getPostAllocaInsertPoint());
V = getTargetHooks().performAddrSpaceCast(
*this, V, getASTAllocaAddressSpace(), LangAS::Default,
Builder.getPtrTy(DestAddrSpace), /*non-null*/ true);
}
return RawAddress(V, Ty, Align, KnownNonNull);
}
/// CreateTempAlloca - This creates an alloca and inserts it into the entry
/// block if \p ArraySize is nullptr, otherwise inserts it at the current
/// insertion point of the builder.
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
const Twine &Name,
llvm::Value *ArraySize) {
llvm::AllocaInst *Alloca;
if (ArraySize)
Alloca = Builder.CreateAlloca(Ty, ArraySize, Name);
else
Alloca =
new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
ArraySize, Name, AllocaInsertPt->getIterator());
if (Allocas) {
Allocas->Add(Alloca);
}
return Alloca;
}
/// CreateDefaultAlignTempAlloca - This creates an alloca with the
/// default alignment of the corresponding LLVM type, which is *not*
/// guaranteed to be related in any way to the expected alignment of
/// an AST type that might have been lowered to Ty.
RawAddress CodeGenFunction::CreateDefaultAlignTempAlloca(llvm::Type *Ty,
const Twine &Name) {
CharUnits Align =
CharUnits::fromQuantity(CGM.getDataLayout().getPrefTypeAlign(Ty));
return CreateTempAlloca(Ty, Align, Name);
}
RawAddress CodeGenFunction::CreateIRTemp(QualType Ty, const Twine &Name) {
CharUnits Align = getContext().getTypeAlignInChars(Ty);
return CreateTempAlloca(ConvertType(Ty), Align, Name);
}
RawAddress CodeGenFunction::CreateMemTemp(QualType Ty, const Twine &Name,
RawAddress *Alloca) {
// FIXME: Should we prefer the preferred type alignment here?
return CreateMemTemp(Ty, getContext().getTypeAlignInChars(Ty), Name, Alloca);
}
RawAddress CodeGenFunction::CreateMemTemp(QualType Ty, CharUnits Align,
const Twine &Name,
RawAddress *Alloca) {
RawAddress Result = CreateTempAlloca(ConvertTypeForMem(Ty), Align, Name,
/*ArraySize=*/nullptr, Alloca);
if (Ty->isConstantMatrixType()) {
auto *ArrayTy = cast<llvm::ArrayType>(Result.getElementType());
auto *VectorTy = llvm::FixedVectorType::get(ArrayTy->getElementType(),
ArrayTy->getNumElements());
Result = Address(Result.getPointer(), VectorTy, Result.getAlignment(),
KnownNonNull);
}
return Result;
}
RawAddress CodeGenFunction::CreateMemTempWithoutCast(QualType Ty,
CharUnits Align,
const Twine &Name) {
return CreateTempAllocaWithoutCast(ConvertTypeForMem(Ty), Align, Name);
}
RawAddress CodeGenFunction::CreateMemTempWithoutCast(QualType Ty,
const Twine &Name) {
return CreateMemTempWithoutCast(Ty, getContext().getTypeAlignInChars(Ty),
Name);
}
/// 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;
SourceLocation Loc = E->getExprLoc();
CGFPOptionsRAII FPOptsRAII(*this, E);
if (!E->getType()->isAnyComplexType())
return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy, Loc);
return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(), BoolTy,
Loc);
}
/// EmitIgnoredExpr - Emit code to compute the specified expression,
/// ignoring the result.
void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
if (E->isPRValue())
return (void)EmitAnyExpr(E, AggValueSlot::ignored(), true);
// if this is a bitfield-resulting conditional operator, we can special case
// emit this. The normal 'EmitLValue' version of this is particularly
// difficult to codegen for, since creating a single "LValue" for two
// different sized arguments here is not particularly doable.
if (const auto *CondOp = dyn_cast<AbstractConditionalOperator>(
E->IgnoreParenNoopCasts(getContext()))) {
if (CondOp->getObjectKind() == OK_BitField)
return EmitIgnoredConditionalOperator(CondOp);
}
// 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 - Similar 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,
Address Location,
Qualifiers Quals,
bool IsInit) {
// FIXME: This function should take an LValue as an argument.
switch (getEvaluationKind(E->getType())) {
case TEK_Complex:
EmitComplexExprIntoLValue(E, MakeAddrLValue(Location, E->getType()),
/*isInit*/ false);
return;
case TEK_Aggregate: {
EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals,
AggValueSlot::IsDestructed_t(IsInit),
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsAliased_t(!IsInit),
AggValueSlot::MayOverlap));
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");
}
void CodeGenFunction::EmitInitializationToLValue(
const Expr *E, LValue LV, AggValueSlot::IsZeroed_t IsZeroed) {
QualType Type = LV.getType();
switch (getEvaluationKind(Type)) {
case TEK_Complex:
EmitComplexExprIntoLValue(E, LV, /*isInit*/ true);
return;
case TEK_Aggregate:
EmitAggExpr(E, AggValueSlot::forLValue(LV, AggValueSlot::IsDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased,
AggValueSlot::MayOverlap, IsZeroed));
return;
case TEK_Scalar:
if (LV.isSimple())
EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false);
else
EmitStoreThroughLValue(RValue::get(EmitScalarExpr(E)), LV);
return;
}
llvm_unreachable("bad evaluation kind");
}
static void
pushTemporaryCleanup(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M,
const Expr *E, Address 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 (auto Lifetime = M->getType().getObjCLifetime()) {
switch (Lifetime) {
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:
CodeGenFunction::Destroyer *Destroy;
CleanupKind CleanupKind;
if (Lifetime == Qualifiers::OCL_Strong) {
const ValueDecl *VD = M->getExtendingDecl();
bool Precise = isa_and_nonnull<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,
M->getType(), *Destroy,
CleanupKind & EHCleanup);
else
CGF.pushLifetimeExtendedDestroy(CleanupKind, ReferenceTemporary,
M->getType(),
*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::FunctionCallee CleanupFn;
llvm::Constant *CleanupArg;
if (E->getType()->isArrayType()) {
CleanupFn = CodeGenFunction(CGF.CGM).generateDestroyHelper(
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.getAddrAndTypeOfCXXStructor(
GlobalDecl(ReferenceTemporaryDtor, Dtor_Complete));
CleanupArg = cast<llvm::Constant>(ReferenceTemporary.emitRawPointer(CGF));
}
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 RawAddress createReferenceTemporary(CodeGenFunction &CGF,
const MaterializeTemporaryExpr *M,
const Expr *Inner,
RawAddress *Alloca = nullptr) {
auto &TCG = CGF.getTargetHooks();
switch (M->getStorageDuration()) {
case SD_FullExpression:
case SD_Automatic: {
// If we have a constant temporary array or record try to promote it into a
// constant global under the same rules a normal constant would've been
// promoted. This is easier on the optimizer and generally emits fewer
// instructions.
QualType Ty = Inner->getType();
if (CGF.CGM.getCodeGenOpts().MergeAllConstants &&
(Ty->isArrayType() || Ty->isRecordType()) &&
Ty.isConstantStorage(CGF.getContext(), true, false))
if (auto Init = ConstantEmitter(CGF).tryEmitAbstract(Inner, Ty)) {
auto AS = CGF.CGM.GetGlobalConstantAddressSpace();
auto *GV = new llvm::GlobalVariable(
CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true,
llvm::GlobalValue::PrivateLinkage, Init, ".ref.tmp", nullptr,
llvm::GlobalValue::NotThreadLocal,
CGF.getContext().getTargetAddressSpace(AS));
CharUnits alignment = CGF.getContext().getTypeAlignInChars(Ty);
GV->setAlignment(alignment.getAsAlign());
llvm::Constant *C = GV;
if (AS != LangAS::Default)
C = TCG.performAddrSpaceCast(
CGF.CGM, GV, AS, LangAS::Default,
llvm::PointerType::get(
CGF.getLLVMContext(),
CGF.getContext().getTargetAddressSpace(LangAS::Default)));
// FIXME: Should we put the new global into a COMDAT?
return RawAddress(C, GV->getValueType(), alignment);
}
return CGF.CreateMemTemp(Ty, "ref.tmp", Alloca);
}
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");
}
/// Helper method to check if the underlying ABI is AAPCS
static bool isAAPCS(const TargetInfo &TargetInfo) {
return TargetInfo.getABI().starts_with("aapcs");
}
LValue CodeGenFunction::
EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *M) {
const Expr *E = M->getSubExpr();
assert((!M->getExtendingDecl() || !isa<VarDecl>(M->getExtendingDecl()) ||
!cast<VarDecl>(M->getExtendingDecl())->isARCPseudoStrong()) &&
"Reference should never be pseudo-strong!");
// FIXME: ideally this would use EmitAnyExprToMem, however, we cannot do so
// as that will cause the lifetime adjustment to be lost for ARC
auto ownership = M->getType().getObjCLifetime();
if (ownership != Qualifiers::OCL_None &&
ownership != Qualifiers::OCL_ExplicitNone) {
RawAddress Object = createReferenceTemporary(*this, M, E);
if (auto *Var = dyn_cast<llvm::GlobalVariable>(Object.getPointer())) {
llvm::Type *Ty = ConvertTypeForMem(E->getType());
Object = Object.withElementType(Ty);
// createReferenceTemporary will promote the temporary to a global with a
// constant initializer if it can. It can only do this to a value of
// ARC-manageable type if the value is global and therefore "immune" to
// ref-counting operations. Therefore we have no need to emit either a
// dynamic initialization or a cleanup and we can just return the address
// of the temporary.
if (Var->hasInitializer())
return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
Var->setInitializer(CGM.EmitNullConstant(E->getType()));
}
LValue RefTempDst = MakeAddrLValue(Object, M->getType(),
AlignmentSource::Decl);
switch (getEvaluationKind(E->getType())) {
default: llvm_unreachable("expected scalar or aggregate expression");
case TEK_Scalar:
EmitScalarInit(E, M->getExtendingDecl(), RefTempDst, false);
break;
case TEK_Aggregate: {
EmitAggExpr(E, AggValueSlot::forAddr(Object,
E->getType().getQualifiers(),
AggValueSlot::IsDestructed,
AggValueSlot::DoesNotNeedGCBarriers,
AggValueSlot::IsNotAliased,
AggValueSlot::DoesNotOverlap));
break;
}
}
pushTemporaryCleanup(*this, M, E, Object);
return RefTempDst;
}
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
for (const auto &Ignored : CommaLHSs)
EmitIgnoredExpr(Ignored);
if (const auto *opaque = dyn_cast<OpaqueValueExpr>(E)) {
if (opaque->getType()->isRecordType()) {
assert(Adjustments.empty());
return EmitOpaqueValueLValue(opaque);
}
}
// Create and initialize the reference temporary.
RawAddress Alloca = Address::invalid();
RawAddress Object = createReferenceTemporary(*this, M, E, &Alloca);
if (auto *Var = dyn_cast<llvm::GlobalVariable>(
Object.getPointer()->stripPointerCasts())) {
llvm::Type *TemporaryType = ConvertTypeForMem(E->getType());
Object = Object.withElementType(TemporaryType);
// If the temporary is a global and has a constant initializer or is a
// constant temporary that we promoted to a global, we may have already
// initialized it.
if (!Var->hasInitializer()) {
Var->setInitializer(CGM.EmitNullConstant(E->getType()));
EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
}
} else {
switch (M->getStorageDuration()) {
case SD_Automatic:
if (auto *Size = EmitLifetimeStart(
CGM.getDataLayout().getTypeAllocSize(Alloca.getElementType()),
Alloca.getPointer())) {
pushCleanupAfterFullExpr<CallLifetimeEnd>(NormalEHLifetimeMarker,
Alloca, Size);
}
break;
case SD_FullExpression: {
if (!ShouldEmitLifetimeMarkers)
break;
// Avoid creating a conditional cleanup just to hold an llvm.lifetime.end
// marker. Instead, start the lifetime of a conditional temporary earlier
// so that it's unconditional. Don't do this with sanitizers which need
// more precise lifetime marks. However when inside an "await.suspend"
// block, we should always avoid conditional cleanup because it creates
// boolean marker that lives across await_suspend, which can destroy coro
// frame.
ConditionalEvaluation *OldConditional = nullptr;
CGBuilderTy::InsertPoint OldIP;
if (isInConditionalBranch() && !E->getType().isDestructedType() &&
((!SanOpts.has(SanitizerKind::HWAddress) &&
!SanOpts.has(SanitizerKind::Memory) &&
!CGM.getCodeGenOpts().SanitizeAddressUseAfterScope) ||
inSuspendBlock())) {
OldConditional = OutermostConditional;
OutermostConditional = nullptr;
OldIP = Builder.saveIP();
llvm::BasicBlock *Block = OldConditional->getStartingBlock();
Builder.restoreIP(CGBuilderTy::InsertPoint(
Block, llvm::BasicBlock::iterator(Block->back())));
}
if (auto *Size = EmitLifetimeStart(
CGM.getDataLayout().getTypeAllocSize(Alloca.getElementType()),
Alloca.getPointer())) {
pushFullExprCleanup<CallLifetimeEnd>(NormalEHLifetimeMarker, Alloca,
Size);
}
if (OldConditional) {
OutermostConditional = OldConditional;
Builder.restoreIP(OldIP);
}
break;
}
default:
break;
}
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 (SubobjectAdjustment &Adjustment : llvm::reverse(Adjustments)) {
switch (Adjustment.Kind) {
case SubobjectAdjustment::DerivedToBaseAdjustment:
Object =
GetAddressOfBaseClass(Object, Adjustment.DerivedToBase.DerivedClass,
Adjustment.DerivedToBase.BasePath->path_begin(),
Adjustment.DerivedToBase.BasePath->path_end(),
/*NullCheckValue=*/ false, E->getExprLoc());
break;
case SubobjectAdjustment::FieldAdjustment: {
LValue LV = MakeAddrLValue(Object, E->getType(), AlignmentSource::Decl);
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 = EmitCXXMemberDataPointerAddress(E, Object, Ptr,
Adjustment.Ptr.MPT);
break;
}
}
}
return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
}
RValue
CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E) {
// Emit the expression as an lvalue.
LValue LV = EmitLValue(E);
assert(LV.isSimple());
llvm::Value *Value = LV.getPointer(*this);
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();
}
static llvm::Value *emitHashMix(CGBuilderTy &Builder, llvm::Value *Acc,
llvm::Value *Ptr) {
llvm::Value *A0 =
Builder.CreateMul(Ptr, Builder.getInt64(0xbf58476d1ce4e5b9u));
llvm::Value *A1 =
Builder.CreateXor(A0, Builder.CreateLShr(A0, Builder.getInt64(31)));
return Builder.CreateXor(Acc, A1);
}
bool CodeGenFunction::isNullPointerAllowed(TypeCheckKind TCK) {
return TCK == TCK_DowncastPointer || TCK == TCK_Upcast ||
TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation;
}
bool CodeGenFunction::isVptrCheckRequired(TypeCheckKind TCK, QualType Ty) {
CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
return (RD && RD->hasDefinition() && RD->isDynamicClass()) &&
(TCK == TCK_MemberAccess || TCK == TCK_MemberCall ||
TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference ||
TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation);
}
bool CodeGenFunction::sanitizePerformTypeCheck() const {
return SanOpts.has(SanitizerKind::Null) ||
SanOpts.has(SanitizerKind::Alignment) ||
SanOpts.has(SanitizerKind::ObjectSize) ||
SanOpts.has(SanitizerKind::Vptr);
}
void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
llvm::Value *Ptr, QualType Ty,
CharUnits Alignment,
SanitizerSet SkippedChecks,
llvm::Value *ArraySize) {
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 (Ptr->getType()->getPointerAddressSpace())
return;
// Don't check pointers to volatile data. The behavior here is implementation-
// defined.
if (Ty.isVolatileQualified())
return;
SanitizerScope SanScope(this);
SmallVector<std::pair<llvm::Value *, SanitizerKind::SanitizerOrdinal>, 3>
Checks;
llvm::BasicBlock *Done = nullptr;
// Quickly determine whether we have a pointer to an alloca. It's possible
// to skip null checks, and some alignment checks, for these pointers. This
// can reduce compile-time significantly.
auto PtrToAlloca = dyn_cast<llvm::AllocaInst>(Ptr->stripPointerCasts());
llvm::Value *True = llvm::ConstantInt::getTrue(getLLVMContext());
llvm::Value *IsNonNull = nullptr;
bool IsGuaranteedNonNull =
SkippedChecks.has(SanitizerKind::Null) || PtrToAlloca;
bool AllowNullPointers = isNullPointerAllowed(TCK);
if ((SanOpts.has(SanitizerKind::Null) || AllowNullPointers) &&
!IsGuaranteedNonNull) {
// The glvalue must not be an empty glvalue.
IsNonNull = Builder.CreateIsNotNull(Ptr);
// The IR builder can constant-fold the null check if the pointer points to
// a constant.
IsGuaranteedNonNull = IsNonNull == True;
// Skip the null check if the pointer is known to be non-null.
if (!IsGuaranteedNonNull) {
if (AllowNullPointers) {
// When performing pointer casts, 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(IsNonNull, Rest, Done);
EmitBlock(Rest);
} else {
Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::SO_Null));
}
}
}
if (SanOpts.has(SanitizerKind::ObjectSize) &&
!SkippedChecks.has(SanitizerKind::ObjectSize) &&
!Ty->isIncompleteType()) {
uint64_t TySize = CGM.getMinimumObjectSize(Ty).getQuantity();
llvm::Value *Size = llvm::ConstantInt::get(IntPtrTy, TySize);
if (ArraySize)
Size = Builder.CreateMul(Size, ArraySize);
// Degenerate case: new X[0] does not need an objectsize check.
llvm::Constant *ConstantSize = dyn_cast<llvm::Constant>(Size);
if (!ConstantSize || !ConstantSize->isNullValue()) {
// 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::Function *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, Tys);
llvm::Value *Min = Builder.getFalse();
llvm::Value *NullIsUnknown = Builder.getFalse();
llvm::Value *Dynamic = Builder.getFalse();
llvm::Value *LargeEnough = Builder.CreateICmpUGE(
Builder.CreateCall(F, {Ptr, Min, NullIsUnknown, Dynamic}), Size);
Checks.push_back(
std::make_pair(LargeEnough, SanitizerKind::SO_ObjectSize));
}
}
llvm::MaybeAlign AlignVal;
llvm::Value *PtrAsInt = nullptr;
if (SanOpts.has(SanitizerKind::Alignment) &&
!SkippedChecks.has(SanitizerKind::Alignment)) {
AlignVal = Alignment.getAsMaybeAlign();
if (!Ty->isIncompleteType() && !AlignVal)
AlignVal = CGM.getNaturalTypeAlignment(Ty, nullptr, nullptr,
/*ForPointeeType=*/true)
.getAsMaybeAlign();
// The glvalue must be suitably aligned.
if (AlignVal && *AlignVal > llvm::Align(1) &&
(!PtrToAlloca || PtrToAlloca->getAlign() < *AlignVal)) {
PtrAsInt = Builder.CreatePtrToInt(Ptr, IntPtrTy);
llvm::Value *Align = Builder.CreateAnd(
PtrAsInt, llvm::ConstantInt::get(IntPtrTy, AlignVal->value() - 1));
llvm::Value *Aligned =
Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0));
if (Aligned != True)
Checks.push_back(std::make_pair(Aligned, SanitizerKind::SO_Alignment));
}
}
if (Checks.size() > 0) {
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(Ty),
llvm::ConstantInt::get(Int8Ty, AlignVal ? llvm::Log2(*AlignVal) : 1),
llvm::ConstantInt::get(Int8Ty, TCK)};
EmitCheck(Checks, SanitizerHandler::TypeMismatch, StaticData,
PtrAsInt ? PtrAsInt : Ptr);
}
// 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
if (SanOpts.has(SanitizerKind::Vptr) &&
!SkippedChecks.has(SanitizerKind::Vptr) && isVptrCheckRequired(TCK, Ty)) {
// Ensure that the pointer is non-null before loading it. If there is no
// compile-time guarantee, reuse the run-time null check or emit a new one.
if (!IsGuaranteedNonNull) {
if (!IsNonNull)
IsNonNull = Builder.CreateIsNotNull(Ptr);
if (!Done)
Done = createBasicBlock("vptr.null");
llvm::BasicBlock *VptrNotNull = createBasicBlock("vptr.not.null");
Builder.CreateCondBr(IsNonNull, VptrNotNull, Done);
EmitBlock(VptrNotNull);
}
// Compute a deterministic hash of the mangled name of the type.
SmallString<64> MangledName;
llvm::raw_svector_ostream Out(MangledName);
CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty.getUnqualifiedType(),
Out);
// Contained in NoSanitizeList based on the mangled type.
if (!CGM.getContext().getNoSanitizeList().containsType(SanitizerKind::Vptr,
Out.str())) {
// Load the vptr, and mix it with TypeHash.
llvm::Value *TypeHash =
llvm::ConstantInt::get(Int64Ty, xxh3_64bits(Out.str()));
llvm::Type *VPtrTy = llvm::PointerType::get(getLLVMContext(), 0);
Address VPtrAddr(Ptr, IntPtrTy, getPointerAlign());
llvm::Value *VPtrVal = GetVTablePtr(VPtrAddr, VPtrTy,
Ty->getAsCXXRecordDecl(),
VTableAuthMode::UnsafeUbsanStrip);
VPtrVal = Builder.CreateBitOrPointerCast(VPtrVal, IntPtrTy);
llvm::Value *Hash =
emitHashMix(Builder, TypeHash, Builder.CreateZExt(VPtrVal, Int64Ty));
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.CreateAlignedLoad(
IntPtrTy, Builder.CreateInBoundsGEP(HashTable, Cache, Indices),
getPointerAlign());
// 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::Value *EqualHash = Builder.CreateICmpEQ(CacheVal, Hash);
llvm::Constant *StaticData[] = {
EmitCheckSourceLocation(Loc),
EmitCheckTypeDescriptor(Ty),
CGM.GetAddrOfRTTIDescriptor(Ty.getUnqualifiedType()),
llvm::ConstantInt::get(Int8Ty, TCK)
};
llvm::Value *DynamicData[] = { Ptr, Hash };
EmitCheck(std::make_pair(EqualHash, SanitizerKind::SO_Vptr),
SanitizerHandler::DynamicTypeCacheMiss, StaticData,
DynamicData);
}
}
if (Done) {
Builder.CreateBr(Done);
EmitBlock(Done);
}
}
llvm::Value *CodeGenFunction::LoadPassedObjectSize(const Expr *E,
QualType EltTy) {
ASTContext &C = getContext();
uint64_t EltSize = C.getTypeSizeInChars(EltTy).getQuantity();
if (!EltSize)
return nullptr;
auto *ArrayDeclRef = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts());
if (!ArrayDeclRef)
return nullptr;
auto *ParamDecl = dyn_cast<ParmVarDecl>(ArrayDeclRef->getDecl());
if (!ParamDecl)
return nullptr;
auto *POSAttr = ParamDecl->getAttr<PassObjectSizeAttr>();
if (!POSAttr)
return nullptr;
// Don't load the size if it's a lower bound.
int POSType = POSAttr->getType();
if (POSType != 0 && POSType != 1)
return nullptr;
// Find the implicit size parameter.
auto PassedSizeIt = SizeArguments.find(ParamDecl);
if (PassedSizeIt == SizeArguments.end())
return nullptr;
const ImplicitParamDecl *PassedSizeDecl = PassedSizeIt->second;
assert(LocalDeclMap.count(PassedSizeDecl) && "Passed size not loadable");
Address AddrOfSize = LocalDeclMap.find(PassedSizeDecl)->second;
llvm::Value *SizeInBytes = EmitLoadOfScalar(AddrOfSize, /*Volatile=*/false,
C.getSizeType(), E->getExprLoc());
llvm::Value *SizeOfElement =
llvm::ConstantInt::get(SizeInBytes->getType(), EltSize);
return Builder.CreateUDiv(SizeInBytes, SizeOfElement);
}
/// 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,
LangOptions::StrictFlexArraysLevelKind
StrictFlexArraysLevel) {
// 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 &&
!CE->getSubExpr()->isFlexibleArrayMemberLike(CGF.getContext(),
StrictFlexArraysLevel)) {
CodeGenFunction::SanitizerScope SanScope(&CGF);
IndexedType = CE->getSubExpr()->getType();
const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe();
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
return CGF.Builder.getInt(CAT->getSize());
if (const auto *VAT = dyn_cast<VariableArrayType>(AT))
return CGF.getVLASize(VAT).NumElts;
// Ignore pass_object_size here. It's not applicable on decayed pointers.
}
}
CodeGenFunction::SanitizerScope SanScope(&CGF);
QualType EltTy{Base->getType()->getPointeeOrArrayElementType(), 0};
if (llvm::Value *POS = CGF.LoadPassedObjectSize(Base, EltTy)) {
IndexedType = Base->getType();
return POS;
}