-
Notifications
You must be signed in to change notification settings - Fork 10.4k
/
Copy pathSILGenConvert.cpp
1981 lines (1718 loc) · 76.5 KB
/
SILGenConvert.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
//===--- SILGenConvert.cpp - Type Conversion Routines ---------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#include "SILGen.h"
#include "ArgumentSource.h"
#include "Conversion.h"
#include "Initialization.h"
#include "LValue.h"
#include "RValue.h"
#include "Scope.h"
#include "SwitchEnumBuilder.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/ConformanceLookup.h"
#include "swift/AST/Decl.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/AST/Types.h"
#include "swift/Basic/Assertions.h"
#include "swift/Basic/SourceManager.h"
#include "swift/Basic/type_traits.h"
#include "swift/SIL/SILArgument.h"
#include "swift/SIL/TypeLowering.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/SaveAndRestore.h"
#include "llvm/Support/raw_ostream.h"
using namespace swift;
using namespace Lowering;
// FIXME: With some changes to their callers, all of the below functions
// could be re-worked to use emitInjectEnum().
ManagedValue
SILGenFunction::emitInjectOptional(SILLocation loc,
const TypeLowering &optTL,
SGFContext ctxt,
llvm::function_ref<ManagedValue(SGFContext)> generator) {
SILType optTy = optTL.getLoweredType();
SILType objectTy = optTy.getOptionalObjectType();
assert(objectTy && "expected type was not optional");
auto someDecl = getASTContext().getOptionalSomeDecl();
// If the value is loadable, just emit and wrap.
// TODO: honor +0 contexts?
if (optTL.isLoadable() || !silConv.useLoweredAddresses()) {
ManagedValue objectResult = generator(SGFContext());
return B.createEnum(loc, objectResult, someDecl, optTy);
}
// Otherwise it's address-only; try to avoid spurious copies by
// evaluating into the context.
// Prepare a buffer for the object value.
return B.bufferForExpr(
loc, optTy.getObjectType(), optTL, ctxt,
[&](SILValue optBuf) {
auto objectBuf = B.createInitEnumDataAddr(loc, optBuf, someDecl, objectTy);
// Evaluate the value in-place into that buffer.
TemporaryInitialization init(objectBuf, CleanupHandle::invalid());
ManagedValue objectResult = generator(SGFContext(&init));
if (!objectResult.isInContext()) {
objectResult.ensurePlusOne(*this, loc)
.forwardInto(*this, loc, objectBuf);
}
// Finalize the outer optional buffer.
B.createInjectEnumAddr(loc, optBuf, someDecl);
});
}
void SILGenFunction::emitInjectOptionalValueInto(SILLocation loc,
ArgumentSource &&value,
SILValue dest,
const TypeLowering &optTL) {
SILType optType = optTL.getLoweredType();
assert(dest->getType() == optType.getAddressType());
auto loweredPayloadTy = optType.getOptionalObjectType();
assert(loweredPayloadTy);
// Project out the payload area.
auto someDecl = getASTContext().getOptionalSomeDecl();
auto destPayload =
B.createInitEnumDataAddr(loc, dest, someDecl,
loweredPayloadTy.getAddressType());
// Emit the value into the payload area.
TemporaryInitialization emitInto(destPayload, CleanupHandle::invalid());
std::move(value).forwardInto(*this, &emitInto);
// Inject the tag.
B.createInjectEnumAddr(loc, dest, someDecl);
}
void SILGenFunction::emitInjectOptionalNothingInto(SILLocation loc,
SILValue dest,
const TypeLowering &optTL) {
assert(optTL.getLoweredType().getOptionalObjectType());
B.createInjectEnumAddr(loc, dest, getASTContext().getOptionalNoneDecl());
}
/// Return a value for an optional ".None" of the specified type. This only
/// works for loadable enum types.
SILValue SILGenFunction::getOptionalNoneValue(SILLocation loc,
const TypeLowering &optTL) {
assert((optTL.isLoadable() || !silConv.useLoweredAddresses()) &&
"Address-only optionals cannot use this");
assert(optTL.getLoweredType().getOptionalObjectType());
return B.createEnum(loc, SILValue(), getASTContext().getOptionalNoneDecl(),
optTL.getLoweredType());
}
/// Return a value for an optional ".Some(x)" of the specified type. This only
/// works for loadable enum types.
ManagedValue SILGenFunction::
getOptionalSomeValue(SILLocation loc, ManagedValue value,
const TypeLowering &optTL) {
assert((optTL.isLoadable() || !silConv.useLoweredAddresses()) &&
"Address-only optionals cannot use this");
SILType optType = optTL.getLoweredType();
auto formalOptType = optType.getASTType();
(void)formalOptType;
assert(formalOptType.getOptionalObjectType());
auto someDecl = getASTContext().getOptionalSomeDecl();
return B.createEnum(loc, value, someDecl, optTL.getLoweredType());
}
auto SILGenFunction::emitSourceLocationArgs(SourceLoc sourceLoc,
SILLocation emitLoc)
-> SourceLocArgs {
auto &ctx = getASTContext();
std::string filename = "";
unsigned line = 0;
unsigned column = 0;
if (sourceLoc.isValid()) {
filename = getMagicFileIDString(sourceLoc);
std::tie(line, column) =
ctx.SourceMgr.getPresumedLineAndColumnForLoc(sourceLoc);
}
bool isASCII = true;
for (unsigned char c : filename) {
if (c > 127) {
isASCII = false;
break;
}
}
auto wordTy = SILType::getBuiltinWordType(ctx);
auto i1Ty = SILType::getBuiltinIntegerType(1, ctx);
SourceLocArgs result;
SILValue literal = B.createStringLiteral(emitLoc, StringRef(filename),
StringLiteralInst::Encoding::UTF8);
result.filenameStartPointer =
ManagedValue::forObjectRValueWithoutOwnership(literal);
// File length
literal = B.createIntegerLiteral(emitLoc, wordTy, filename.size());
result.filenameLength =
ManagedValue::forObjectRValueWithoutOwnership(literal);
// File is ascii
literal = B.createIntegerLiteral(emitLoc, i1Ty, isASCII);
result.filenameIsAscii =
ManagedValue::forObjectRValueWithoutOwnership(literal);
// Line
literal = B.createIntegerLiteral(emitLoc, wordTy, line);
result.line = ManagedValue::forObjectRValueWithoutOwnership(literal);
// Column
literal = B.createIntegerLiteral(emitLoc, wordTy, column);
result.column = ManagedValue::forObjectRValueWithoutOwnership(literal);
return result;
}
ManagedValue
SILGenFunction::emitPreconditionOptionalHasValue(SILLocation loc,
ManagedValue optional,
bool isImplicitUnwrap) {
// Generate code to check if the optional is present, and if not, abort with a message
// (provided by the stdlib).
SILBasicBlock *contBB = createBasicBlock();
SILBasicBlock *failBB = createBasicBlock();
bool hadCleanup = optional.hasCleanup();
bool hadLValue = optional.isLValue();
auto someDecl = getASTContext().getOptionalSomeDecl();
auto noneDecl = getASTContext().getOptionalNoneDecl();
bool isAddress = optional.getType().isAddress();
bool isBorrow = !optional.isPlusOneOrTrivial(*this);
SwitchEnumInst *switchEnum = nullptr;
if (isAddress) {
// We forward in the creation routine for
// unchecked_take_enum_data_addr. switch_enum_addr is a +0 operation.
B.createSwitchEnumAddr(loc, optional.getValue(),
/*defaultDest*/ nullptr,
{{someDecl, contBB}, {noneDecl, failBB}});
} else if (isBorrow) {
hadCleanup = false;
hadLValue = false;
switchEnum = B.createSwitchEnum(loc, optional.getValue(),
/*defaultDest*/ nullptr,
{{someDecl, contBB}, {noneDecl, failBB}});
} else {
optional = optional.ensurePlusOne(*this, loc);
hadCleanup = true;
hadLValue = false;
switchEnum = B.createSwitchEnum(loc, optional.forward(*this),
/*defaultDest*/ nullptr,
{{someDecl, contBB}, {noneDecl, failBB}});
}
B.emitBlock(failBB);
// Call the standard library implementation of _diagnoseUnexpectedNilOptional.
if (auto diagnoseFailure =
getASTContext().getDiagnoseUnexpectedNilOptional()) {
auto args = emitSourceLocationArgs(loc.getSourceLoc(), loc);
auto i1Ty = SILType::getBuiltinIntegerType(1, getASTContext());
auto isImplicitUnwrapLiteral =
B.createIntegerLiteral(loc, i1Ty, isImplicitUnwrap);
auto isImplicitUnwrapValue =
ManagedValue::forObjectRValueWithoutOwnership(isImplicitUnwrapLiteral);
emitApplyOfLibraryIntrinsic(loc, diagnoseFailure, SubstitutionMap(),
{
args.filenameStartPointer,
args.filenameLength,
args.filenameIsAscii,
args.line,
isImplicitUnwrapValue
},
SGFContext());
}
B.createUnreachable(ArtificialUnreachableLocation());
B.clearInsertionPoint();
B.emitBlock(contBB);
ManagedValue result;
if (isAddress) {
SILType payloadType = optional.getType().getOptionalObjectType();
result =
B.createUncheckedTakeEnumDataAddr(loc, optional, someDecl, payloadType);
} else {
result = B.createOptionalSomeResult(switchEnum);
}
if (hadCleanup) {
return result;
}
if (hadLValue) {
return ManagedValue::forLValue(result.forward(*this));
}
return ManagedValue::forBorrowedRValue(result.forward(*this));
}
SILValue SILGenFunction::emitDoesOptionalHaveValue(SILLocation loc,
SILValue addrOrValue) {
auto boolTy = SILType::getBuiltinIntegerType(1, getASTContext());
SILValue yes = B.createIntegerLiteral(loc, boolTy, 1);
SILValue no = B.createIntegerLiteral(loc, boolTy, 0);
auto someDecl = getASTContext().getOptionalSomeDecl();
if (addrOrValue->getType().isAddress())
return B.createSelectEnumAddr(loc, addrOrValue, boolTy, no,
std::make_pair(someDecl, yes));
return B.createSelectEnum(loc, addrOrValue, boolTy, no,
std::make_pair(someDecl, yes));
}
ManagedValue SILGenFunction::emitCheckedGetOptionalValueFrom(SILLocation loc,
ManagedValue src,
bool isImplicitUnwrap,
const TypeLowering &optTL,
SGFContext C) {
// TODO: Make this take optTL.
return emitPreconditionOptionalHasValue(loc, src, isImplicitUnwrap);
}
ManagedValue SILGenFunction::emitUncheckedGetOptionalValueFrom(
SILLocation loc, ManagedValue addrOrValue, const TypeLowering &optTL,
SGFContext C) {
SILType origPayloadTy = addrOrValue.getType().getOptionalObjectType();
auto someDecl = getASTContext().getOptionalSomeDecl();
// Take the payload from the optional.
if (!addrOrValue.getType().isAddress()) {
return B.createUncheckedEnumData(loc, addrOrValue, someDecl);
}
// Cheat a bit in the +0 case--UncheckedTakeEnumData will never actually
// invalidate an Optional enum value. This is specific to optionals.
ManagedValue payload = B.createUncheckedTakeEnumDataAddr(
loc, addrOrValue, someDecl, origPayloadTy);
if (!optTL.isLoadable())
return payload;
// If we do not have a cleanup on our address, use a load_borrow.
if (!payload.hasCleanup()) {
return B.createLoadBorrow(loc, payload);
}
// Otherwise, perform a load take.
return B.createLoadTake(loc, payload);
}
ManagedValue
SILGenFunction::emitOptionalSome(SILLocation loc, SILType optTy,
ValueProducerRef produceValue,
SGFContext C) {
// If we're emitting into a conversion, try to peephole the
// injection into it.
if (auto optInit = C.getAsConversion()) {
const auto &optConversion = optInit->getConversion();
auto adjustment = optConversion.adjustForInitialOptionalInjection();
// If the adjustment gives us a conversion that produces an optional
// value, that completely takes over emission. This generally happens
// only because of bridging.
if (adjustment.isInjection()) {
return optInit->emitWithAdjustedConversion(*this, loc,
adjustment.getInjectionConversion(),
produceValue);
// If the adjustment gives us a conversion that produces a non-optional
// value, we need to produce the value under that conversion and then
// inject that into an optional. We can do that by recursing. This
// will terminate because the recursive call to emitOptionalSome gets
// passed a strictly "smaller" context: the parent context of the
// converting context we were passed.
} else if (adjustment.isValue()) {
auto produceConvertedValue = [&](SILGenFunction &SGF,
SILLocation loc,
SGFContext C) {
return SGF.emitConvertedRValue(loc, adjustment.getValueConversion(),
C, produceValue);
};
auto result = emitOptionalSome(loc, optConversion.getLoweredResultType(),
produceConvertedValue,
optInit->getFinalContext());
optInit->initWithConvertedValue(*this, loc, result);
optInit->finishInitialization(*this);
return ManagedValue::forInContext();
}
}
auto &optTL = getTypeLowering(optTy);
// If the type is loadable or we're not lowering address-only types
// in SILGen, use a simple scalar pattern.
if (!silConv.useLoweredAddresses() || optTL.isLoadable()) {
auto value = produceValue(*this, loc, SGFContext());
return getOptionalSomeValue(loc, value, optTL);
}
// Otherwise, emit into memory, preferably into an address from
// the context.
// Get an address to emit into.
SILValue optAddr = getBufferForExprResult(loc, optTy, C);
auto someDecl = getASTContext().getOptionalSomeDecl();
auto valueTy = optTy.getOptionalObjectType();
auto &valueTL = getTypeLowering(valueTy);
// Project the value buffer within the address.
SILValue valueAddr =
B.createInitEnumDataAddr(loc, optAddr, someDecl,
valueTy.getAddressType());
// Emit into the value buffer.
auto valueInit = useBufferAsTemporary(valueAddr, valueTL);
ManagedValue value = produceValue(*this, loc, SGFContext(valueInit.get()));
if (!value.isInContext()) {
valueInit->copyOrInitValueInto(*this, loc, value, /*isInit*/ true);
valueInit->finishInitialization(*this);
}
// Kill the cleanup on the value.
valueInit->getManagedAddress().forward(*this);
// Finish the optional.
B.createInjectEnumAddr(loc, optAddr, someDecl);
return manageBufferForExprResult(optAddr, optTL, C);
}
/// Emit an optional-to-optional transformation.
ManagedValue
SILGenFunction::emitOptionalToOptional(SILLocation loc,
ManagedValue input,
SILType resultTy,
ValueTransformRef transformValue,
SGFContext C) {
auto &Ctx = getASTContext();
// If the input is known to be 'none' just emit a 'none' value of the right
// result type right away.
auto &resultTL = getTypeLowering(resultTy);
if (auto *EI = dyn_cast<EnumInst>(input.getValue())) {
if (EI->getElement() == Ctx.getOptionalNoneDecl()) {
if (!(resultTL.isAddressOnly() && silConv.useLoweredAddresses())) {
SILValue none = B.createEnum(loc, SILValue(), EI->getElement(),
resultTy);
return emitManagedRValueWithCleanup(none);
}
}
}
// Otherwise perform a dispatch.
auto contBB = createBasicBlock();
auto isNotPresentBB = createBasicBlock();
auto isPresentBB = createBasicBlock();
// All conversions happen at +1.
input = input.ensurePlusOne(*this, loc);
SwitchEnumBuilder SEBuilder(B, loc, input);
SILType noOptResultTy = resultTy.getOptionalObjectType();
assert(noOptResultTy);
// Create a temporary for the output optional.
//
// If the result is address-only, we need to return something in memory,
// otherwise the result is the BBArgument in the merge point.
// TODO: use the SGFContext passed in.
ManagedValue resultAddress;
bool addressOnly = resultTL.isAddressOnly() && silConv.useLoweredAddresses();
if (addressOnly) {
resultAddress = emitManagedBufferWithCleanup(
emitTemporaryAllocation(loc, resultTy), resultTL);
}
ValueOwnershipKind resultOwnership = OwnershipKind::Any;
SEBuilder.addOptionalSomeCase(
isPresentBB, contBB, [&](ManagedValue input, SwitchCaseFullExpr &&scope) {
// If we have an address only type, we want to match the old behavior of
// transforming the underlying type instead of the optional type. This
// ensures that we use the more efficient non-generic code paths when
// possible.
if (getTypeLowering(input.getType()).isAddressOnly() &&
silConv.useLoweredAddresses()) {
auto *someDecl = Ctx.getOptionalSomeDecl();
input = B.createUncheckedTakeEnumDataAddr(
loc, input, someDecl, input.getType().getOptionalObjectType());
}
ManagedValue result = transformValue(*this, loc, input, noOptResultTy,
SGFContext());
resultOwnership = result.getValue()->getOwnershipKind();
if (!addressOnly) {
SILValue some = B.createOptionalSome(loc, result).forward(*this);
return scope.exitAndBranch(loc, some);
}
RValue R(*this, loc, noOptResultTy.getASTType(), result);
ArgumentSource resultValueRV(loc, std::move(R));
emitInjectOptionalValueInto(loc, std::move(resultValueRV),
resultAddress.getValue(), resultTL);
return scope.exitAndBranch(loc);
});
SEBuilder.addOptionalNoneCase(
isNotPresentBB, contBB,
[&](ManagedValue input, SwitchCaseFullExpr &&scope) {
if (!addressOnly) {
SILValue none =
B.createManagedOptionalNone(loc, resultTy).forward(*this);
return scope.exitAndBranch(loc, none);
}
emitInjectOptionalNothingInto(loc, resultAddress.getValue(), resultTL);
return scope.exitAndBranch(loc);
});
std::move(SEBuilder).emit();
B.emitBlock(contBB);
if (addressOnly)
return resultAddress;
// This phi's ownership is derived from the transformed value's
// ownership, not the input ownership. Transformation can convert a value with
// no ownership to an owned value.
return B.createPhi(resultTL.getLoweredType(), resultOwnership);
}
SILGenFunction::OpaqueValueRAII::~OpaqueValueRAII() {
auto entry = Self.OpaqueValues.find(OpaqueValue);
assert(entry != Self.OpaqueValues.end());
Self.OpaqueValues.erase(entry);
}
RValue
SILGenFunction::emitPointerToPointer(SILLocation loc,
ManagedValue input,
CanType inputType,
CanType outputType,
SGFContext C) {
auto converter = getASTContext().getConvertPointerToPointerArgument();
auto origValue = input;
if (silConv.useLoweredAddresses()) {
// The generic function currently always requires indirection, but pointers
// are always loadable.
auto origBuf = emitTemporaryAllocation(loc, input.getType());
B.emitStoreValueOperation(loc, input.forward(*this), origBuf,
StoreOwnershipQualifier::Init);
origValue = emitManagedBufferWithCleanup(origBuf);
}
// Invoke the conversion intrinsic to convert to the destination type.
SmallVector<Type, 2> replacementTypes;
replacementTypes.push_back(inputType);
replacementTypes.push_back(outputType);
auto genericSig = converter->getGenericSignature();
auto subMap =
SubstitutionMap::get(genericSig, replacementTypes,
LookUpConformanceInModule());
return emitApplyOfLibraryIntrinsic(loc, converter, subMap, origValue, C);
}
namespace {
/// This is an initialization for an address-only existential in memory.
class ExistentialInitialization final : public SingleBufferInitialization {
SILValue existential;
CanType concreteFormalType;
ArrayRef<ProtocolConformanceRef> conformances;
ExistentialRepresentation repr;
// Initialized lazily when the address for initialization is demanded.
SILValue concreteBuffer;
CleanupHandle deinitExistentialCleanup;
public:
/// \param existential The existential container
/// \param concreteFormalType Unlowered AST type of value
/// \param conformances Conformances for concrete type to existential's
/// protocols
ExistentialInitialization(SILGenFunction &SGF,
SILValue existential,
CanType concreteFormalType,
ArrayRef<ProtocolConformanceRef> conformances,
ExistentialRepresentation repr)
: existential(existential),
concreteFormalType(concreteFormalType),
conformances(conformances),
repr(repr)
{
assert(existential->getType().isAddress());
// Create a cleanup to deallocate an allocated but uninitialized concrete
// type buffer.
// It won't be activated until that buffer is formed later, though.
deinitExistentialCleanup =
SGF.enterDeinitExistentialCleanup(CleanupState::Dormant,
existential, concreteFormalType, repr);
}
SILValue getAddressForInPlaceInitialization(SILGenFunction &SGF,
SILLocation loc) override {
// Create the buffer when needed, because in some cases the type may
// be the opened type from another existential that hasn't been opened
// at the point the existential destination was formed.
assert(!concreteBuffer && "concrete buffer already formed?!");
auto concreteLoweredType =
SGF.getLoweredType(AbstractionPattern::getOpaque(), concreteFormalType);
switch (repr) {
case ExistentialRepresentation::Opaque: {
concreteBuffer = SGF.B.createInitExistentialAddr(loc, existential,
concreteFormalType,
concreteLoweredType.getAddressType(),
conformances);
break;
}
case ExistentialRepresentation::Boxed: {
auto box = SGF.B.createAllocExistentialBox(loc,
existential->getType().getObjectType(),
concreteFormalType,
conformances);
concreteBuffer = SGF.B.createProjectExistentialBox(loc,
concreteLoweredType.getAddressType(),
box);
SGF.B.createStore(loc, box, existential,
StoreOwnershipQualifier::Init);
break;
}
case ExistentialRepresentation::Class:
case ExistentialRepresentation::Metatype:
case ExistentialRepresentation::None:
llvm_unreachable("not supported");
}
// Activate the cleanup to deallocate the buffer we just allocated, should
SGF.Cleanups.setCleanupState(deinitExistentialCleanup,
CleanupState::Active);
return concreteBuffer;
}
bool isInPlaceInitializationOfGlobal() const override {
return isa_and_nonnull<GlobalAddrInst>(existential);
}
void finishInitialization(SILGenFunction &SGF) override {
SingleBufferInitialization::finishInitialization(SGF);
// We've fully initialized the existential by this point, so we can
// retire the partial cleanup.
SGF.Cleanups.setCleanupState(deinitExistentialCleanup,
CleanupState::Dead);
}
};
} // end anonymous namespace
ManagedValue SILGenFunction::emitExistentialErasure(
SILLocation loc,
CanType concreteFormalType,
const TypeLowering &concreteTL,
const TypeLowering &existentialTL,
ArrayRef<ProtocolConformanceRef> conformances,
SGFContext C,
llvm::function_ref<ManagedValue (SGFContext)> F,
bool allowEmbeddedNSError) {
// Mark the needed conformances as used.
for (auto conformance : conformances)
SGM.useConformance(conformance);
// If we're erasing to the 'Error' type, we might be able to get an NSError
// representation more efficiently.
auto &ctx = getASTContext();
auto *nsErrorDecl = ctx.getNSErrorDecl();
if (ctx.LangOpts.EnableObjCInterop && conformances.size() == 1 &&
conformances[0].getRequirement() == ctx.getErrorDecl() &&
nsErrorDecl && referenceAllowed(nsErrorDecl)) {
// If the concrete type is NSError or a subclass thereof, just erase it
// directly.
auto nsErrorType = ctx.getNSErrorType()->getCanonicalType();
if (nsErrorType->isExactSuperclassOf(concreteFormalType)) {
ManagedValue nsError = F(SGFContext());
if (nsErrorType != concreteFormalType) {
nsError = B.createUpcast(loc, nsError, getLoweredType(nsErrorType));
}
return emitBridgedToNativeError(loc, nsError);
}
// If the concrete type is known to conform to _BridgedStoredNSError,
// call the _nsError witness getter to extract the NSError directly,
// then just erase the NSError.
auto storedNSErrorConformance =
SGM.getConformanceToBridgedStoredNSError(loc, concreteFormalType);
if (storedNSErrorConformance) {
auto nsErrorVar = SGM.getNSErrorRequirement(loc);
if (!nsErrorVar) return emitUndef(existentialTL.getLoweredType());
SubstitutionMap nsErrorVarSubstitutions;
// Devirtualize. Maybe this should be done implicitly by
// emitPropertyLValue?
if (storedNSErrorConformance.isConcrete()) {
if (auto normal = dyn_cast<NormalProtocolConformance>(
storedNSErrorConformance.getConcrete())) {
if (auto witnessVar = normal->getWitness(nsErrorVar)) {
nsErrorVar = cast<VarDecl>(witnessVar.getDecl());
nsErrorVarSubstitutions = witnessVar.getSubstitutions();
}
}
}
ManagedValue nativeError = F(SGFContext());
FormalEvaluationScope writebackScope(*this);
ManagedValue nsError =
emitRValueForStorageLoad(
loc, nativeError, concreteFormalType,
/*super*/ false, nsErrorVar, PreparedArguments(),
nsErrorVarSubstitutions,
AccessSemantics::Ordinary, nsErrorType, SGFContext())
.getAsSingleValue(*this, loc);
return emitBridgedToNativeError(loc, nsError);
}
// Otherwise, if it's an archetype, try calling the _getEmbeddedNSError()
// witness to try to dig out the embedded NSError. But don't do this
// when we're being called recursively.
if (isa<ArchetypeType>(concreteFormalType) && allowEmbeddedNSError) {
auto contBB = createBasicBlock();
auto isNotPresentBB = createBasicBlock();
auto isPresentBB = createBasicBlock();
// Call swift_stdlib_getErrorEmbeddedNSError to attempt to extract an
// NSError from the value.
auto getEmbeddedNSErrorFn = SGM.getGetErrorEmbeddedNSError(loc);
if (!getEmbeddedNSErrorFn)
return emitUndef(existentialTL.getLoweredType());
auto getEmbeddedNSErrorSubstitutions =
SubstitutionMap::getProtocolSubstitutions(ctx.getErrorDecl(),
concreteFormalType,
conformances[0]);
ManagedValue concreteValue = F(SGFContext());
ManagedValue potentialNSError =
emitApplyOfLibraryIntrinsic(loc,
getEmbeddedNSErrorFn,
getEmbeddedNSErrorSubstitutions,
{ concreteValue.copy(*this, loc) },
SGFContext())
.getAsSingleValue(*this, loc);
// We're going to consume 'concreteValue' in exactly one branch,
// so kill its cleanup now and recreate it on both branches.
(void) concreteValue.forward(*this);
// Check whether we got an NSError back.
std::pair<EnumElementDecl*, SILBasicBlock*> cases[] = {
{ ctx.getOptionalSomeDecl(), isPresentBB },
{ ctx.getOptionalNoneDecl(), isNotPresentBB }
};
auto *switchEnum =
B.createSwitchEnum(loc, potentialNSError.forward(*this),
/*default*/ nullptr, cases);
// If we did get an NSError, emit the existential erasure from that
// NSError.
B.emitBlock(isPresentBB);
SILValue branchArg;
{
// Don't allow cleanups to escape the conditional block.
FullExpr presentScope(Cleanups, CleanupLocation(loc));
enterDestroyCleanup(concreteValue.getValue());
// Receive the error value. It's typed as an 'AnyObject' for
// layering reasons, so perform an unchecked cast down to NSError.
auto nsError = B.createOptionalSomeResult(switchEnum);
nsError = B.createUncheckedRefCast(loc, nsError,
getLoweredType(nsErrorType));
branchArg = emitBridgedToNativeError(loc, nsError).forward(*this);
}
B.createBranch(loc, contBB, branchArg);
// If we did not get an NSError, just directly emit the existential.
// Since this is a recursive call, make sure we don't end up in this
// path again.
B.emitBlock(isNotPresentBB);
{
FullExpr presentScope(Cleanups, CleanupLocation(loc));
concreteValue = emitManagedRValueWithCleanup(concreteValue.getValue());
branchArg = emitExistentialErasure(loc, concreteFormalType, concreteTL,
existentialTL, conformances,
SGFContext(),
[&](SGFContext C) {
return concreteValue;
},
/*allowEmbeddedNSError=*/false)
.forward(*this);
}
B.createBranch(loc, contBB, branchArg);
// Continue.
B.emitBlock(contBB);
SILValue existentialResult = contBB->createPhiArgument(
existentialTL.getLoweredType(), OwnershipKind::Owned);
return emitManagedRValueWithCleanup(existentialResult, existentialTL);
}
}
switch (existentialTL.getLoweredType().getObjectType()
.getPreferredExistentialRepresentation(concreteFormalType)) {
case ExistentialRepresentation::None:
llvm_unreachable("not an existential type");
case ExistentialRepresentation::Metatype: {
assert(existentialTL.isLoadable());
SILValue metatype = F(SGFContext()).getUnmanagedValue();
assert(metatype->getType().castTo<AnyMetatypeType>()->getRepresentation()
== MetatypeRepresentation::Thick);
auto upcast =
B.createInitExistentialMetatype(loc, metatype,
existentialTL.getLoweredType(),
conformances);
return ManagedValue::forObjectRValueWithoutOwnership(upcast);
}
case ExistentialRepresentation::Class: {
assert(existentialTL.isLoadable());
ManagedValue sub = F(SGFContext());
assert(concreteFormalType->isBridgeableObjectType());
return B.createInitExistentialRef(loc, existentialTL.getLoweredType(),
concreteFormalType, sub, conformances);
}
case ExistentialRepresentation::Boxed: {
// We defer allocation of the box to when the address is demanded.
// Create a stack slot to hold the box once it's allocated.
SILValue boxValue;
auto buf = B.bufferForExpr(
loc, existentialTL.getLoweredType(), existentialTL, C,
[&](SILValue existential) {
// Initialize the existential in-place.
ExistentialInitialization init(*this, existential,
concreteFormalType,
conformances,
ExistentialRepresentation::Boxed);
ManagedValue mv = F(SGFContext(&init));
if (!mv.isInContext()) {
init.copyOrInitValueInto(*this, loc, mv.ensurePlusOne(*this, loc),
/*init*/ true);
init.finishInitialization(*this);
}
});
if (buf.isInContext()) {
return buf;
}
auto value = B.createLoad(loc, buf.forward(*this),
LoadOwnershipQualifier::Take);
return emitManagedRValueWithCleanup(value);
}
case ExistentialRepresentation::Opaque: {
// If the concrete value is a pseudogeneric archetype, first erase it to
// its upper bound.
auto anyObjectTy = getASTContext().getAnyObjectType();
auto eraseToAnyObject =
[&, concreteFormalType, F](SGFContext C) -> ManagedValue {
auto concreteValue = F(SGFContext());
assert(concreteFormalType->isBridgeableObjectType());
return B.createInitExistentialRef(
loc, SILType::getPrimitiveObjectType(anyObjectTy), concreteFormalType,
concreteValue, conformances);
};
if (this->F.getLoweredFunctionType()->isPseudogeneric()) {
if (anyObjectTy && concreteFormalType->is<ArchetypeType>()) {
concreteFormalType = anyObjectTy;
// The original conformances are no good because they have the wrong
// (pseudogeneric) subject type.
conformances = collectExistentialConformances(
concreteFormalType, anyObjectTy);
F = eraseToAnyObject;
}
}
if (!silConv.useLoweredAddresses()) {
// We should never create new buffers just for init_existential under
// opaque values mode: This is a case of an opaque value that we can
// "treat" as a by-value one
ManagedValue sub = F(SGFContext());
return B.createInitExistentialValue(
loc, existentialTL.getLoweredType(), concreteFormalType,
sub, conformances);
}
// Allocate the existential.
return B.bufferForExpr(
loc, existentialTL.getLoweredType(), existentialTL, C,
[&](SILValue existential) {
// Initialize the existential in-place.
ExistentialInitialization init(*this, existential,
concreteFormalType,
conformances,
ExistentialRepresentation::Opaque);
ManagedValue mv = F(SGFContext(&init));
if (!mv.isInContext()) {
init.copyOrInitValueInto(*this, loc, mv.ensurePlusOne(*this, loc),
/*init*/ true);
init.finishInitialization(*this);
}
});
}
}
llvm_unreachable("Unhandled ExistentialRepresentation in switch.");
}
ManagedValue SILGenFunction::emitClassMetatypeToObject(SILLocation loc,
ManagedValue v,
SILType resultTy) {
SILValue value = v.getUnmanagedValue();
// Convert the metatype to objc representation.
auto metatypeTy = value->getType().castTo<MetatypeType>();
auto objcMetatypeTy = CanMetatypeType::get(metatypeTy.getInstanceType(),
MetatypeRepresentation::ObjC);
value = B.createThickToObjCMetatype(loc, value,
SILType::getPrimitiveObjectType(objcMetatypeTy));
// Convert to an object reference.
value = B.createObjCMetatypeToObject(loc, value, resultTy);
return emitManagedRValueWithCleanup(value);
}
ManagedValue SILGenFunction::emitExistentialMetatypeToObject(SILLocation loc,
ManagedValue v,
SILType resultTy) {
SILValue value = v.getUnmanagedValue();
// Convert the metatype to objc representation.
auto metatypeTy = value->getType().castTo<ExistentialMetatypeType>();
auto objcMetatypeTy = CanExistentialMetatypeType::get(
metatypeTy.getInstanceType(),
MetatypeRepresentation::ObjC);
value = B.createThickToObjCMetatype(loc, value,
SILType::getPrimitiveObjectType(objcMetatypeTy));
// Convert to an object reference.
value = B.createObjCExistentialMetatypeToObject(loc, value, resultTy);
return emitManagedRValueWithCleanup(value);
}
ManagedValue SILGenFunction::emitProtocolMetatypeToObject(SILLocation loc,
CanType inputTy,
SILType resultTy) {
auto protocolType = inputTy->castTo<MetatypeType>()->getInstanceType();
if (auto existential = protocolType->getAs<ExistentialType>())
protocolType = existential->getConstraintType();
ProtocolDecl *protocol = protocolType->castTo<ProtocolType>()->getDecl();
SILValue value = B.createObjCProtocol(loc, protocol, resultTy);
// Protocol objects, despite being global objects, inherit default reference
// counting semantics from NSObject, so we need to retain the protocol
// reference when we use it to prevent it being released and attempting to
// deallocate itself. It doesn't matter if we ever actually clean up that
// retain though.
value = B.createCopyValue(loc, value);
return emitManagedRValueWithCleanup(value);
}
ManagedValue
SILGenFunction::emitOpenExistential(
SILLocation loc,
ManagedValue existentialValue,
SILType loweredOpenedType,
AccessKind accessKind) {
assert(isInFormalEvaluationScope());
SILType existentialType = existentialValue.getType();
switch (existentialType.getPreferredExistentialRepresentation()) {
case ExistentialRepresentation::Opaque: {
// With CoW existentials we can't consume the boxed value inside of
// the existential. (We could only do so after a uniqueness check on
// the box holding the value).
if (existentialType.isAddress()) {
OpenedExistentialAccess allowedAccess =
getOpenedExistentialAccessFor(accessKind);
if (!loweredOpenedType.isAddress()) {
assert(!silConv.useLoweredAddresses() &&
"Non-address loweredOpenedType is only allowed under opaque "
"value mode");
loweredOpenedType = loweredOpenedType.getAddressType();
}
SILValue archetypeValue =
B.createOpenExistentialAddr(loc, existentialValue.getValue(),
loweredOpenedType, allowedAccess);
return ManagedValue::forBorrowedAddressRValue(archetypeValue);
} else {
// borrow the existential and return an unmanaged opened value.
return B.createOpenExistentialValue(
loc, existentialValue, loweredOpenedType);
}
}
case ExistentialRepresentation::Metatype:
assert(existentialType.isObject());
return B.createOpenExistentialMetatype(