aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/llvm16/lib/Support/YAMLTraits.cpp
blob: 4eb0b3afd563068b0310eb2731d5563b75e2dd26 (plain) (blame)
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
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
//===- lib/Support/YAMLTraits.cpp -----------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/Support/YAMLTraits.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/LineIterator.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/VersionTuple.h"
#include "llvm/Support/YAMLParser.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <cstring>
#include <string>
#include <vector>

using namespace llvm;
using namespace yaml;

//===----------------------------------------------------------------------===//
//  IO
//===----------------------------------------------------------------------===//

IO::IO(void *Context) : Ctxt(Context) {}

IO::~IO() = default;

void *IO::getContext() const {
  return Ctxt;
}

void IO::setContext(void *Context) {
  Ctxt = Context;
}

void IO::setAllowUnknownKeys(bool Allow) {
  llvm_unreachable("Only supported for Input");
}

//===----------------------------------------------------------------------===//
//  Input
//===----------------------------------------------------------------------===//

Input::Input(StringRef InputContent, void *Ctxt,
             SourceMgr::DiagHandlerTy DiagHandler, void *DiagHandlerCtxt)
    : IO(Ctxt), Strm(new Stream(InputContent, SrcMgr, false, &EC)) {
  if (DiagHandler)
    SrcMgr.setDiagHandler(DiagHandler, DiagHandlerCtxt);
  DocIterator = Strm->begin();
}

Input::Input(MemoryBufferRef Input, void *Ctxt,
             SourceMgr::DiagHandlerTy DiagHandler, void *DiagHandlerCtxt)
    : IO(Ctxt), Strm(new Stream(Input, SrcMgr, false, &EC)) {
  if (DiagHandler)
    SrcMgr.setDiagHandler(DiagHandler, DiagHandlerCtxt);
  DocIterator = Strm->begin();
}

Input::~Input() = default;

std::error_code Input::error() { return EC; }

// Pin the vtables to this file.
void Input::HNode::anchor() {}
void Input::EmptyHNode::anchor() {}
void Input::ScalarHNode::anchor() {}
void Input::MapHNode::anchor() {}
void Input::SequenceHNode::anchor() {}

bool Input::outputting() const {
  return false;
}

bool Input::setCurrentDocument() {
  if (DocIterator != Strm->end()) {
    Node *N = DocIterator->getRoot();
    if (!N) {
      EC = make_error_code(errc::invalid_argument);
      return false;
    }

    if (isa<NullNode>(N)) {
      // Empty files are allowed and ignored
      ++DocIterator;
      return setCurrentDocument();
    }
    TopNode = createHNodes(N);
    CurrentNode = TopNode.get();
    return true;
  }
  return false;
}

bool Input::nextDocument() {
  return ++DocIterator != Strm->end();
}

const Node *Input::getCurrentNode() const {
  return CurrentNode ? CurrentNode->_node : nullptr;
}

bool Input::mapTag(StringRef Tag, bool Default) {
  // CurrentNode can be null if setCurrentDocument() was unable to
  // parse the document because it was invalid or empty.
  if (!CurrentNode)
    return false;

  std::string foundTag = CurrentNode->_node->getVerbatimTag();
  if (foundTag.empty()) {
    // If no tag found and 'Tag' is the default, say it was found.
    return Default;
  }
  // Return true iff found tag matches supplied tag.
  return Tag.equals(foundTag);
}

void Input::beginMapping() {
  if (EC)
    return;
  // CurrentNode can be null if the document is empty.
  MapHNode *MN = dyn_cast_or_null<MapHNode>(CurrentNode);
  if (MN) {
    MN->ValidKeys.clear();
  }
}

std::vector<StringRef> Input::keys() {
  MapHNode *MN = dyn_cast<MapHNode>(CurrentNode);
  std::vector<StringRef> Ret;
  if (!MN) {
    setError(CurrentNode, "not a mapping");
    return Ret;
  }
  for (auto &P : MN->Mapping)
    Ret.push_back(P.first());
  return Ret;
}

bool Input::preflightKey(const char *Key, bool Required, bool, bool &UseDefault,
                         void *&SaveInfo) {
  UseDefault = false;
  if (EC)
    return false;

  // CurrentNode is null for empty documents, which is an error in case required
  // nodes are present.
  if (!CurrentNode) {
    if (Required)
      EC = make_error_code(errc::invalid_argument);
    return false;
  }

  MapHNode *MN = dyn_cast<MapHNode>(CurrentNode);
  if (!MN) {
    if (Required || !isa<EmptyHNode>(CurrentNode))
      setError(CurrentNode, "not a mapping");
    else
      UseDefault = true;
    return false;
  }
  MN->ValidKeys.push_back(Key);
  HNode *Value = MN->Mapping[Key].first.get();
  if (!Value) {
    if (Required)
      setError(CurrentNode, Twine("missing required key '") + Key + "'");
    else
      UseDefault = true;
    return false;
  }
  SaveInfo = CurrentNode;
  CurrentNode = Value;
  return true;
}

void Input::postflightKey(void *saveInfo) {
  CurrentNode = reinterpret_cast<HNode *>(saveInfo);
}

void Input::endMapping() {
  if (EC)
    return;
  // CurrentNode can be null if the document is empty.
  MapHNode *MN = dyn_cast_or_null<MapHNode>(CurrentNode);
  if (!MN)
    return;
  for (const auto &NN : MN->Mapping) {
    if (!is_contained(MN->ValidKeys, NN.first())) {
      const SMRange &ReportLoc = NN.second.second;
      if (!AllowUnknownKeys) {
        setError(ReportLoc, Twine("unknown key '") + NN.first() + "'");
        break;
      } else
        reportWarning(ReportLoc, Twine("unknown key '") + NN.first() + "'");
    }
  }
}

void Input::beginFlowMapping() { beginMapping(); }

void Input::endFlowMapping() { endMapping(); }

unsigned Input::beginSequence() {
  if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode))
    return SQ->Entries.size();
  if (isa<EmptyHNode>(CurrentNode))
    return 0;
  // Treat case where there's a scalar "null" value as an empty sequence.
  if (ScalarHNode *SN = dyn_cast<ScalarHNode>(CurrentNode)) {
    if (isNull(SN->value()))
      return 0;
  }
  // Any other type of HNode is an error.
  setError(CurrentNode, "not a sequence");
  return 0;
}

void Input::endSequence() {
}

bool Input::preflightElement(unsigned Index, void *&SaveInfo) {
  if (EC)
    return false;
  if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
    SaveInfo = CurrentNode;
    CurrentNode = SQ->Entries[Index].get();
    return true;
  }
  return false;
}

void Input::postflightElement(void *SaveInfo) {
  CurrentNode = reinterpret_cast<HNode *>(SaveInfo);
}

unsigned Input::beginFlowSequence() { return beginSequence(); }

bool Input::preflightFlowElement(unsigned index, void *&SaveInfo) {
  if (EC)
    return false;
  if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
    SaveInfo = CurrentNode;
    CurrentNode = SQ->Entries[index].get();
    return true;
  }
  return false;
}

void Input::postflightFlowElement(void *SaveInfo) {
  CurrentNode = reinterpret_cast<HNode *>(SaveInfo);
}

void Input::endFlowSequence() {
}

void Input::beginEnumScalar() {
  ScalarMatchFound = false;
}

bool Input::matchEnumScalar(const char *Str, bool) {
  if (ScalarMatchFound)
    return false;
  if (ScalarHNode *SN = dyn_cast<ScalarHNode>(CurrentNode)) {
    if (SN->value().equals(Str)) {
      ScalarMatchFound = true;
      return true;
    }
  }
  return false;
}

bool Input::matchEnumFallback() {
  if (ScalarMatchFound)
    return false;
  ScalarMatchFound = true;
  return true;
}

void Input::endEnumScalar() {
  if (!ScalarMatchFound) {
    setError(CurrentNode, "unknown enumerated scalar");
  }
}

bool Input::beginBitSetScalar(bool &DoClear) {
  BitValuesUsed.clear();
  if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
    BitValuesUsed.resize(SQ->Entries.size());
  } else {
    setError(CurrentNode, "expected sequence of bit values");
  }
  DoClear = true;
  return true;
}

bool Input::bitSetMatch(const char *Str, bool) {
  if (EC)
    return false;
  if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
    unsigned Index = 0;
    for (auto &N : SQ->Entries) {
      if (ScalarHNode *SN = dyn_cast<ScalarHNode>(N.get())) {
        if (SN->value().equals(Str)) {
          BitValuesUsed[Index] = true;
          return true;
        }
      } else {
        setError(CurrentNode, "unexpected scalar in sequence of bit values");
      }
      ++Index;
    }
  } else {
    setError(CurrentNode, "expected sequence of bit values");
  }
  return false;
}

void Input::endBitSetScalar() {
  if (EC)
    return;
  if (SequenceHNode *SQ = dyn_cast<SequenceHNode>(CurrentNode)) {
    assert(BitValuesUsed.size() == SQ->Entries.size());
    for (unsigned i = 0; i < SQ->Entries.size(); ++i) {
      if (!BitValuesUsed[i]) {
        setError(SQ->Entries[i].get(), "unknown bit value");
        return;
      }
    }
  }
}

void Input::scalarString(StringRef &S, QuotingType) {
  if (ScalarHNode *SN = dyn_cast<ScalarHNode>(CurrentNode)) {
    S = SN->value();
  } else {
    setError(CurrentNode, "unexpected scalar");
  }
}

void Input::blockScalarString(StringRef &S) { scalarString(S, QuotingType::None); }

void Input::scalarTag(std::string &Tag) {
  Tag = CurrentNode->_node->getVerbatimTag();
}

void Input::setError(HNode *hnode, const Twine &message) {
  assert(hnode && "HNode must not be NULL");
  setError(hnode->_node, message);
}

NodeKind Input::getNodeKind() {
  if (isa<ScalarHNode>(CurrentNode))
    return NodeKind::Scalar;
  else if (isa<MapHNode>(CurrentNode))
    return NodeKind::Map;
  else if (isa<SequenceHNode>(CurrentNode))
    return NodeKind::Sequence;
  llvm_unreachable("Unsupported node kind");
}

void Input::setError(Node *node, const Twine &message) {
  Strm->printError(node, message);
  EC = make_error_code(errc::invalid_argument);
}

void Input::setError(const SMRange &range, const Twine &message) {
  Strm->printError(range, message);
  EC = make_error_code(errc::invalid_argument);
}

void Input::reportWarning(HNode *hnode, const Twine &message) {
  assert(hnode && "HNode must not be NULL");
  Strm->printError(hnode->_node, message, SourceMgr::DK_Warning);
}

void Input::reportWarning(Node *node, const Twine &message) {
  Strm->printError(node, message, SourceMgr::DK_Warning);
}

void Input::reportWarning(const SMRange &range, const Twine &message) {
  Strm->printError(range, message, SourceMgr::DK_Warning);
}

std::unique_ptr<Input::HNode> Input::createHNodes(Node *N) {
  SmallString<128> StringStorage;
  if (ScalarNode *SN = dyn_cast<ScalarNode>(N)) {
    StringRef KeyStr = SN->getValue(StringStorage);
    if (!StringStorage.empty()) {
      // Copy string to permanent storage
      KeyStr = StringStorage.str().copy(StringAllocator);
    }
    return std::make_unique<ScalarHNode>(N, KeyStr);
  } else if (BlockScalarNode *BSN = dyn_cast<BlockScalarNode>(N)) {
    StringRef ValueCopy = BSN->getValue().copy(StringAllocator);
    return std::make_unique<ScalarHNode>(N, ValueCopy);
  } else if (SequenceNode *SQ = dyn_cast<SequenceNode>(N)) {
    auto SQHNode = std::make_unique<SequenceHNode>(N);
    for (Node &SN : *SQ) {
      auto Entry = createHNodes(&SN);
      if (EC)
        break;
      SQHNode->Entries.push_back(std::move(Entry));
    }
    return std::move(SQHNode);
  } else if (MappingNode *Map = dyn_cast<MappingNode>(N)) {
    auto mapHNode = std::make_unique<MapHNode>(N);
    for (KeyValueNode &KVN : *Map) {
      Node *KeyNode = KVN.getKey();
      ScalarNode *Key = dyn_cast_or_null<ScalarNode>(KeyNode);
      Node *Value = KVN.getValue();
      if (!Key || !Value) {
        if (!Key)
          setError(KeyNode, "Map key must be a scalar");
        if (!Value)
          setError(KeyNode, "Map value must not be empty");
        break;
      }
      StringStorage.clear();
      StringRef KeyStr = Key->getValue(StringStorage);
      if (!StringStorage.empty()) {
        // Copy string to permanent storage
        KeyStr = StringStorage.str().copy(StringAllocator);
      }
      auto ValueHNode = createHNodes(Value);
      if (EC)
        break;
      mapHNode->Mapping[KeyStr] =
          std::make_pair(std::move(ValueHNode), KeyNode->getSourceRange());
    }
    return std::move(mapHNode);
  } else if (isa<NullNode>(N)) {
    return std::make_unique<EmptyHNode>(N);
  } else {
    setError(N, "unknown node kind");
    return nullptr;
  }
}

void Input::setError(const Twine &Message) {
  setError(CurrentNode, Message);
}

void Input::setAllowUnknownKeys(bool Allow) { AllowUnknownKeys = Allow; }

bool Input::canElideEmptySequence() {
  return false;
}

//===----------------------------------------------------------------------===//
//  Output
//===----------------------------------------------------------------------===//

Output::Output(raw_ostream &yout, void *context, int WrapColumn)
    : IO(context), Out(yout), WrapColumn(WrapColumn) {}

Output::~Output() = default;

bool Output::outputting() const {
  return true;
}

void Output::beginMapping() {
  StateStack.push_back(inMapFirstKey);
  PaddingBeforeContainer = Padding;
  Padding = "\n";
}

bool Output::mapTag(StringRef Tag, bool Use) {
  if (Use) {
    // If this tag is being written inside a sequence we should write the start
    // of the sequence before writing the tag, otherwise the tag won't be
    // attached to the element in the sequence, but rather the sequence itself.
    bool SequenceElement = false;
    if (StateStack.size() > 1) {
      auto &E = StateStack[StateStack.size() - 2];
      SequenceElement = inSeqAnyElement(E) || inFlowSeqAnyElement(E);
    }
    if (SequenceElement && StateStack.back() == inMapFirstKey) {
      newLineCheck();
    } else {
      output(" ");
    }
    output(Tag);
    if (SequenceElement) {
      // If we're writing the tag during the first element of a map, the tag
      // takes the place of the first element in the sequence.
      if (StateStack.back() == inMapFirstKey) {
        StateStack.pop_back();
        StateStack.push_back(inMapOtherKey);
      }
      // Tags inside maps in sequences should act as keys in the map from a
      // formatting perspective, so we always want a newline in a sequence.
      Padding = "\n";
    }
  }
  return Use;
}

void Output::endMapping() {
  // If we did not map anything, we should explicitly emit an empty map
  if (StateStack.back() == inMapFirstKey) {
    Padding = PaddingBeforeContainer;
    newLineCheck();
    output("{}");
    Padding = "\n";
  }
  StateStack.pop_back();
}

std::vector<StringRef> Output::keys() {
  report_fatal_error("invalid call");
}

bool Output::preflightKey(const char *Key, bool Required, bool SameAsDefault,
                          bool &UseDefault, void *&SaveInfo) {
  UseDefault = false;
  SaveInfo = nullptr;
  if (Required || !SameAsDefault || WriteDefaultValues) {
    auto State = StateStack.back();
    if (State == inFlowMapFirstKey || State == inFlowMapOtherKey) {
      flowKey(Key);
    } else {
      newLineCheck();
      paddedKey(Key);
    }
    return true;
  }
  return false;
}

void Output::postflightKey(void *) {
  if (StateStack.back() == inMapFirstKey) {
    StateStack.pop_back();
    StateStack.push_back(inMapOtherKey);
  } else if (StateStack.back() == inFlowMapFirstKey) {
    StateStack.pop_back();
    StateStack.push_back(inFlowMapOtherKey);
  }
}

void Output::beginFlowMapping() {
  StateStack.push_back(inFlowMapFirstKey);
  newLineCheck();
  ColumnAtMapFlowStart = Column;
  output("{ ");
}

void Output::endFlowMapping() {
  StateStack.pop_back();
  outputUpToEndOfLine(" }");
}

void Output::beginDocuments() {
  outputUpToEndOfLine("---");
}

bool Output::preflightDocument(unsigned index) {
  if (index > 0)
    outputUpToEndOfLine("\n---");
  return true;
}

void Output::postflightDocument() {
}

void Output::endDocuments() {
  output("\n...\n");
}

unsigned Output::beginSequence() {
  StateStack.push_back(inSeqFirstElement);
  PaddingBeforeContainer = Padding;
  Padding = "\n";
  return 0;
}

void Output::endSequence() {
  // If we did not emit anything, we should explicitly emit an empty sequence
  if (StateStack.back() == inSeqFirstElement) {
    Padding = PaddingBeforeContainer;
    newLineCheck(/*EmptySequence=*/true);
    output("[]");
    Padding = "\n";
  }
  StateStack.pop_back();
}

bool Output::preflightElement(unsigned, void *&SaveInfo) {
  SaveInfo = nullptr;
  return true;
}

void Output::postflightElement(void *) {
  if (StateStack.back() == inSeqFirstElement) {
    StateStack.pop_back();
    StateStack.push_back(inSeqOtherElement);
  } else if (StateStack.back() == inFlowSeqFirstElement) {
    StateStack.pop_back();
    StateStack.push_back(inFlowSeqOtherElement);
  }
}

unsigned Output::beginFlowSequence() {
  StateStack.push_back(inFlowSeqFirstElement);
  newLineCheck();
  ColumnAtFlowStart = Column;
  output("[ ");
  NeedFlowSequenceComma = false;
  return 0;
}

void Output::endFlowSequence() {
  StateStack.pop_back();
  outputUpToEndOfLine(" ]");
}

bool Output::preflightFlowElement(unsigned, void *&SaveInfo) {
  if (NeedFlowSequenceComma)
    output(", ");
  if (WrapColumn && Column > WrapColumn) {
    output("\n");
    for (int i = 0; i < ColumnAtFlowStart; ++i)
      output(" ");
    Column = ColumnAtFlowStart;
    output("  ");
  }
  SaveInfo = nullptr;
  return true;
}

void Output::postflightFlowElement(void *) {
  NeedFlowSequenceComma = true;
}

void Output::beginEnumScalar() {
  EnumerationMatchFound = false;
}

bool Output::matchEnumScalar(const char *Str, bool Match) {
  if (Match && !EnumerationMatchFound) {
    newLineCheck();
    outputUpToEndOfLine(Str);
    EnumerationMatchFound = true;
  }
  return false;
}

bool Output::matchEnumFallback() {
  if (EnumerationMatchFound)
    return false;
  EnumerationMatchFound = true;
  return true;
}

void Output::endEnumScalar() {
  if (!EnumerationMatchFound)
    llvm_unreachable("bad runtime enum value");
}

bool Output::beginBitSetScalar(bool &DoClear) {
  newLineCheck();
  output("[ ");
  NeedBitValueComma = false;
  DoClear = false;
  return true;
}

bool Output::bitSetMatch(const char *Str, bool Matches) {
  if (Matches) {
    if (NeedBitValueComma)
      output(", ");
    output(Str);
    NeedBitValueComma = true;
  }
  return false;
}

void Output::endBitSetScalar() {
  outputUpToEndOfLine(" ]");
}

void Output::scalarString(StringRef &S, QuotingType MustQuote) {
  newLineCheck();
  if (S.empty()) {
    // Print '' for the empty string because leaving the field empty is not
    // allowed.
    outputUpToEndOfLine("''");
    return;
  }
  if (MustQuote == QuotingType::None) {
    // Only quote if we must.
    outputUpToEndOfLine(S);
    return;
  }

  const char *const Quote = MustQuote == QuotingType::Single ? "'" : "\"";
  output(Quote); // Starting quote.

  // When using double-quoted strings (and only in that case), non-printable characters may be
  // present, and will be escaped using a variety of unicode-scalar and special short-form
  // escapes. This is handled in yaml::escape.
  if (MustQuote == QuotingType::Double) {
    output(yaml::escape(S, /* EscapePrintable= */ false));
    outputUpToEndOfLine(Quote);
    return;
  }

  unsigned i = 0;
  unsigned j = 0;
  unsigned End = S.size();
  const char *Base = S.data();

  // When using single-quoted strings, any single quote ' must be doubled to be escaped.
  while (j < End) {
    if (S[j] == '\'') {                    // Escape quotes.
      output(StringRef(&Base[i], j - i));  // "flush".
      output(StringLiteral("''"));         // Print it as ''
      i = j + 1;
    }
    ++j;
  }
  output(StringRef(&Base[i], j - i));
  outputUpToEndOfLine(Quote); // Ending quote.
}

void Output::blockScalarString(StringRef &S) {
  if (!StateStack.empty())
    newLineCheck();
  output(" |");
  outputNewLine();

  unsigned Indent = StateStack.empty() ? 1 : StateStack.size();

  auto Buffer = MemoryBuffer::getMemBuffer(S, "", false);
  for (line_iterator Lines(*Buffer, false); !Lines.is_at_end(); ++Lines) {
    for (unsigned I = 0; I < Indent; ++I) {
      output("  ");
    }
    output(*Lines);
    outputNewLine();
  }
}

void Output::scalarTag(std::string &Tag) {
  if (Tag.empty())
    return;
  newLineCheck();
  output(Tag);
  output(" ");
}

void Output::setError(const Twine &message) {
}

bool Output::canElideEmptySequence() {
  // Normally, with an optional key/value where the value is an empty sequence,
  // the whole key/value can be not written.  But, that produces wrong yaml
  // if the key/value is the only thing in the map and the map is used in
  // a sequence.  This detects if the this sequence is the first key/value
  // in map that itself is embedded in a sequence.
  if (StateStack.size() < 2)
    return true;
  if (StateStack.back() != inMapFirstKey)
    return true;
  return !inSeqAnyElement(StateStack[StateStack.size() - 2]);
}

void Output::output(StringRef s) {
  Column += s.size();
  Out << s;
}

void Output::outputUpToEndOfLine(StringRef s) {
  output(s);
  if (StateStack.empty() || (!inFlowSeqAnyElement(StateStack.back()) &&
                             !inFlowMapAnyKey(StateStack.back())))
    Padding = "\n";
}

void Output::outputNewLine() {
  Out << "\n";
  Column = 0;
}

// if seq at top, indent as if map, then add "- "
// if seq in middle, use "- " if firstKey, else use "  "
//

void Output::newLineCheck(bool EmptySequence) {
  if (Padding != "\n") {
    output(Padding);
    Padding = {};
    return;
  }
  outputNewLine();
  Padding = {};

  if (StateStack.size() == 0 || EmptySequence)
    return;

  unsigned Indent = StateStack.size() - 1;
  bool OutputDash = false;

  if (StateStack.back() == inSeqFirstElement ||
      StateStack.back() == inSeqOtherElement) {
    OutputDash = true;
  } else if ((StateStack.size() > 1) &&
             ((StateStack.back() == inMapFirstKey) ||
              inFlowSeqAnyElement(StateStack.back()) ||
              (StateStack.back() == inFlowMapFirstKey)) &&
             inSeqAnyElement(StateStack[StateStack.size() - 2])) {
    --Indent;
    OutputDash = true;
  }

  for (unsigned i = 0; i < Indent; ++i) {
    output("  ");
  }
  if (OutputDash) {
    output("- ");
  }
}

void Output::paddedKey(StringRef key) {
  output(key);
  output(":");
  const char *spaces = "                ";
  if (key.size() < strlen(spaces))
    Padding = &spaces[key.size()];
  else
    Padding = " ";
}

void Output::flowKey(StringRef Key) {
  if (StateStack.back() == inFlowMapOtherKey)
    output(", ");
  if (WrapColumn && Column > WrapColumn) {
    output("\n");
    for (int I = 0; I < ColumnAtMapFlowStart; ++I)
      output(" ");
    Column = ColumnAtMapFlowStart;
    output("  ");
  }
  output(Key);
  output(": ");
}

NodeKind Output::getNodeKind() { report_fatal_error("invalid call"); }

bool Output::inSeqAnyElement(InState State) {
  return State == inSeqFirstElement || State == inSeqOtherElement;
}

bool Output::inFlowSeqAnyElement(InState State) {
  return State == inFlowSeqFirstElement || State == inFlowSeqOtherElement;
}

bool Output::inMapAnyKey(InState State) {
  return State == inMapFirstKey || State == inMapOtherKey;
}

bool Output::inFlowMapAnyKey(InState State) {
  return State == inFlowMapFirstKey || State == inFlowMapOtherKey;
}

//===----------------------------------------------------------------------===//
//  traits for built-in types
//===----------------------------------------------------------------------===//

void ScalarTraits<bool>::output(const bool &Val, void *, raw_ostream &Out) {
  Out << (Val ? "true" : "false");
}

StringRef ScalarTraits<bool>::input(StringRef Scalar, void *, bool &Val) {
  if (std::optional<bool> Parsed = parseBool(Scalar)) {
    Val = *Parsed;
    return StringRef();
  }
  return "invalid boolean";
}

void ScalarTraits<StringRef>::output(const StringRef &Val, void *,
                                     raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<StringRef>::input(StringRef Scalar, void *,
                                         StringRef &Val) {
  Val = Scalar;
  return StringRef();
}

void ScalarTraits<std::string>::output(const std::string &Val, void *,
                                       raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<std::string>::input(StringRef Scalar, void *,
                                           std::string &Val) {
  Val = Scalar.str();
  return StringRef();
}

void ScalarTraits<uint8_t>::output(const uint8_t &Val, void *,
                                   raw_ostream &Out) {
  // use temp uin32_t because ostream thinks uint8_t is a character
  uint32_t Num = Val;
  Out << Num;
}

StringRef ScalarTraits<uint8_t>::input(StringRef Scalar, void *, uint8_t &Val) {
  unsigned long long n;
  if (getAsUnsignedInteger(Scalar, 0, n))
    return "invalid number";
  if (n > 0xFF)
    return "out of range number";
  Val = n;
  return StringRef();
}

void ScalarTraits<uint16_t>::output(const uint16_t &Val, void *,
                                    raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<uint16_t>::input(StringRef Scalar, void *,
                                        uint16_t &Val) {
  unsigned long long n;
  if (getAsUnsignedInteger(Scalar, 0, n))
    return "invalid number";
  if (n > 0xFFFF)
    return "out of range number";
  Val = n;
  return StringRef();
}

void ScalarTraits<uint32_t>::output(const uint32_t &Val, void *,
                                    raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<uint32_t>::input(StringRef Scalar, void *,
                                        uint32_t &Val) {
  unsigned long long n;
  if (getAsUnsignedInteger(Scalar, 0, n))
    return "invalid number";
  if (n > 0xFFFFFFFFUL)
    return "out of range number";
  Val = n;
  return StringRef();
}

void ScalarTraits<uint64_t>::output(const uint64_t &Val, void *,
                                    raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<uint64_t>::input(StringRef Scalar, void *,
                                        uint64_t &Val) {
  unsigned long long N;
  if (getAsUnsignedInteger(Scalar, 0, N))
    return "invalid number";
  Val = N;
  return StringRef();
}

void ScalarTraits<int8_t>::output(const int8_t &Val, void *, raw_ostream &Out) {
  // use temp in32_t because ostream thinks int8_t is a character
  int32_t Num = Val;
  Out << Num;
}

StringRef ScalarTraits<int8_t>::input(StringRef Scalar, void *, int8_t &Val) {
  long long N;
  if (getAsSignedInteger(Scalar, 0, N))
    return "invalid number";
  if ((N > 127) || (N < -128))
    return "out of range number";
  Val = N;
  return StringRef();
}

void ScalarTraits<int16_t>::output(const int16_t &Val, void *,
                                   raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<int16_t>::input(StringRef Scalar, void *, int16_t &Val) {
  long long N;
  if (getAsSignedInteger(Scalar, 0, N))
    return "invalid number";
  if ((N > INT16_MAX) || (N < INT16_MIN))
    return "out of range number";
  Val = N;
  return StringRef();
}

void ScalarTraits<int32_t>::output(const int32_t &Val, void *,
                                   raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<int32_t>::input(StringRef Scalar, void *, int32_t &Val) {
  long long N;
  if (getAsSignedInteger(Scalar, 0, N))
    return "invalid number";
  if ((N > INT32_MAX) || (N < INT32_MIN))
    return "out of range number";
  Val = N;
  return StringRef();
}

void ScalarTraits<int64_t>::output(const int64_t &Val, void *,
                                   raw_ostream &Out) {
  Out << Val;
}

StringRef ScalarTraits<int64_t>::input(StringRef Scalar, void *, int64_t &Val) {
  long long N;
  if (getAsSignedInteger(Scalar, 0, N))
    return "invalid number";
  Val = N;
  return StringRef();
}

void ScalarTraits<double>::output(const double &Val, void *, raw_ostream &Out) {
  Out << format("%g", Val);
}

StringRef ScalarTraits<double>::input(StringRef Scalar, void *, double &Val) {
  if (to_float(Scalar, Val))
    return StringRef();
  return "invalid floating point number";
}

void ScalarTraits<float>::output(const float &Val, void *, raw_ostream &Out) {
  Out << format("%g", Val);
}

StringRef ScalarTraits<float>::input(StringRef Scalar, void *, float &Val) {
  if (to_float(Scalar, Val))
    return StringRef();
  return "invalid floating point number";
}

void ScalarTraits<Hex8>::output(const Hex8 &Val, void *, raw_ostream &Out) {
  Out << format("0x%" PRIX8, (uint8_t)Val);
}

StringRef ScalarTraits<Hex8>::input(StringRef Scalar, void *, Hex8 &Val) {
  unsigned long long n;
  if (getAsUnsignedInteger(Scalar, 0, n))
    return "invalid hex8 number";
  if (n > 0xFF)
    return "out of range hex8 number";
  Val = n;
  return StringRef();
}

void ScalarTraits<Hex16>::output(const Hex16 &Val, void *, raw_ostream &Out) {
  Out << format("0x%" PRIX16, (uint16_t)Val);
}

StringRef ScalarTraits<Hex16>::input(StringRef Scalar, void *, Hex16 &Val) {
  unsigned long long n;
  if (getAsUnsignedInteger(Scalar, 0, n))
    return "invalid hex16 number";
  if (n > 0xFFFF)
    return "out of range hex16 number";
  Val = n;
  return StringRef();
}

void ScalarTraits<Hex32>::output(const Hex32 &Val, void *, raw_ostream &Out) {
  Out << format("0x%" PRIX32, (uint32_t)Val);
}

StringRef ScalarTraits<Hex32>::input(StringRef Scalar, void *, Hex32 &Val) {
  unsigned long long n;
  if (getAsUnsignedInteger(Scalar, 0, n))
    return "invalid hex32 number";
  if (n > 0xFFFFFFFFUL)
    return "out of range hex32 number";
  Val = n;
  return StringRef();
}

void ScalarTraits<Hex64>::output(const Hex64 &Val, void *, raw_ostream &Out) {
  Out << format("0x%" PRIX64, (uint64_t)Val);
}

StringRef ScalarTraits<Hex64>::input(StringRef Scalar, void *, Hex64 &Val) {
  unsigned long long Num;
  if (getAsUnsignedInteger(Scalar, 0, Num))
    return "invalid hex64 number";
  Val = Num;
  return StringRef();
}

void ScalarTraits<VersionTuple>::output(const VersionTuple &Val, void *,
                                        llvm::raw_ostream &Out) {
  Out << Val.getAsString();
}

StringRef ScalarTraits<VersionTuple>::input(StringRef Scalar, void *,
                                            VersionTuple &Val) {
  if (Val.tryParse(Scalar))
    return "invalid version format";
  return StringRef();
}