aboutsummaryrefslogtreecommitdiff
path: root/clang/include/clang/Sema/Initialization.h
blob: 8feb66995f95cc186c4dcc595cf443dc380d5baf (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
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
//===- Initialization.h - Semantic Analysis for Initializers ----*- C++ -*-===//
//
// 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 file provides supporting data types for initialization of objects.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_SEMA_INITIALIZATION_H
#define LLVM_CLANG_SEMA_INITIALIZATION_H

#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclAccessPair.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Sema/Overload.h"
#include "clang/Sema/Ownership.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Casting.h"
#include <cassert>
#include <cstdint>
#include <string>

namespace clang {

class APValue;
class CXXBaseSpecifier;
class CXXConstructorDecl;
class ObjCMethodDecl;
class Sema;

/// Describes an entity that is being initialized.
class alignas(8) InitializedEntity {
public:
  /// Specifies the kind of entity being initialized.
  enum EntityKind {
    /// The entity being initialized is a variable.
    EK_Variable,

    /// The entity being initialized is a function parameter.
    EK_Parameter,

    /// The entity being initialized is a non-type template parameter.
    EK_TemplateParameter,

    /// The entity being initialized is the result of a function call.
    EK_Result,

    /// The entity being initialized is the result of a statement expression.
    EK_StmtExprResult,

    /// The entity being initialized is an exception object that
    /// is being thrown.
    EK_Exception,

    /// The entity being initialized is a non-static data member
    /// subobject.
    EK_Member,

    /// The entity being initialized is an element of an array.
    EK_ArrayElement,

    /// The entity being initialized is an object (or array of
    /// objects) allocated via new.
    EK_New,

    /// The entity being initialized is a temporary object.
    EK_Temporary,

    /// The entity being initialized is a base member subobject.
    EK_Base,

    /// The initialization is being done by a delegating constructor.
    EK_Delegating,

    /// The entity being initialized is an element of a vector.
    /// or vector.
    EK_VectorElement,

    /// The entity being initialized is a field of block descriptor for
    /// the copied-in c++ object.
    EK_BlockElement,

    /// The entity being initialized is a field of block descriptor for the
    /// copied-in lambda object that's used in the lambda to block conversion.
    EK_LambdaToBlockConversionBlockElement,

    /// The entity being initialized is the real or imaginary part of a
    /// complex number.
    EK_ComplexElement,

    /// The entity being initialized is the field that captures a
    /// variable in a lambda.
    EK_LambdaCapture,

    /// The entity being initialized is the initializer for a compound
    /// literal.
    EK_CompoundLiteralInit,

    /// The entity being implicitly initialized back to the formal
    /// result type.
    EK_RelatedResult,

    /// The entity being initialized is a function parameter; function
    /// is member of group of audited CF APIs.
    EK_Parameter_CF_Audited,

    /// The entity being initialized is a structured binding of a
    /// decomposition declaration.
    EK_Binding,

    // Note: err_init_conversion_failed in DiagnosticSemaKinds.td uses this
    // enum as an index for its first %select.  When modifying this list,
    // that diagnostic text needs to be updated as well.
  };

private:
  /// The kind of entity being initialized.
  EntityKind Kind;

  /// If non-NULL, the parent entity in which this
  /// initialization occurs.
  const InitializedEntity *Parent = nullptr;

  /// The type of the object or reference being initialized.
  QualType Type;

  /// The mangling number for the next reference temporary to be created.
  mutable unsigned ManglingNumber = 0;

  struct LN {
    /// When Kind == EK_Result, EK_Exception, EK_New, the
    /// location of the 'return', 'throw', or 'new' keyword,
    /// respectively. When Kind == EK_Temporary, the location where
    /// the temporary is being created.
    SourceLocation Location;

    /// Whether the entity being initialized may end up using the
    /// named return value optimization (NRVO).
    bool NRVO;
  };

  struct VD {
    /// The VarDecl, FieldDecl, or BindingDecl being initialized.
    ValueDecl *VariableOrMember;

    /// When Kind == EK_Member, whether this is an implicit member
    /// initialization in a copy or move constructor. These can perform array
    /// copies.
    bool IsImplicitFieldInit;

    /// When Kind == EK_Member, whether this is the initial initialization
    /// check for a default member initializer.
    bool IsDefaultMemberInit;
  };

  struct C {
    /// The name of the variable being captured by an EK_LambdaCapture.
    IdentifierInfo *VarID;

    /// The source location at which the capture occurs.
    SourceLocation Location;
  };

  union {
    /// When Kind == EK_Variable, EK_Member, EK_Binding, or
    /// EK_TemplateParameter, the variable, binding, or template parameter.
    VD Variable;

    /// When Kind == EK_RelatedResult, the ObjectiveC method where
    /// result type was implicitly changed to accommodate ARC semantics.
    ObjCMethodDecl *MethodDecl;

    /// When Kind == EK_Parameter, the ParmVarDecl, with the
    /// integer indicating whether the parameter is "consumed".
    llvm::PointerIntPair<ParmVarDecl *, 1> Parameter;

    /// When Kind == EK_Temporary or EK_CompoundLiteralInit, the type
    /// source information for the temporary.
    TypeSourceInfo *TypeInfo;

    struct LN LocAndNRVO;

    /// When Kind == EK_Base, the base specifier that provides the
    /// base class. The integer specifies whether the base is an inherited
    /// virtual base.
    llvm::PointerIntPair<const CXXBaseSpecifier *, 1> Base;

    /// When Kind == EK_ArrayElement, EK_VectorElement, or
    /// EK_ComplexElement, the index of the array or vector element being
    /// initialized.
    unsigned Index;

    struct C Capture;
  };

  InitializedEntity() {};

  /// Create the initialization entity for a variable.
  InitializedEntity(VarDecl *Var, EntityKind EK = EK_Variable)
      : Kind(EK), Type(Var->getType()), Variable{Var, false, false} {}

  /// Create the initialization entity for the result of a
  /// function, throwing an object, performing an explicit cast, or
  /// initializing a parameter for which there is no declaration.
  InitializedEntity(EntityKind Kind, SourceLocation Loc, QualType Type,
                    bool NRVO = false)
      : Kind(Kind), Type(Type) {
    new (&LocAndNRVO) LN;
    LocAndNRVO.Location = Loc;
    LocAndNRVO.NRVO = NRVO;
  }

  /// Create the initialization entity for a member subobject.
  InitializedEntity(FieldDecl *Member, const InitializedEntity *Parent,
                    bool Implicit, bool DefaultMemberInit)
      : Kind(EK_Member), Parent(Parent), Type(Member->getType()),
        Variable{Member, Implicit, DefaultMemberInit} {}

  /// Create the initialization entity for an array element.
  InitializedEntity(ASTContext &Context, unsigned Index,
                    const InitializedEntity &Parent);

  /// Create the initialization entity for a lambda capture.
  InitializedEntity(IdentifierInfo *VarID, QualType FieldType, SourceLocation Loc)
      : Kind(EK_LambdaCapture), Type(FieldType) {
    new (&Capture) C;
    Capture.VarID = VarID;
    Capture.Location = Loc;
  }

public:
  /// Create the initialization entity for a variable.
  static InitializedEntity InitializeVariable(VarDecl *Var) {
    return InitializedEntity(Var);
  }

  /// Create the initialization entity for a parameter.
  static InitializedEntity InitializeParameter(ASTContext &Context,
                                               ParmVarDecl *Parm) {
    return InitializeParameter(Context, Parm, Parm->getType());
  }

  /// Create the initialization entity for a parameter, but use
  /// another type.
  static InitializedEntity
  InitializeParameter(ASTContext &Context, ParmVarDecl *Parm, QualType Type) {
    bool Consumed = (Context.getLangOpts().ObjCAutoRefCount &&
                     Parm->hasAttr<NSConsumedAttr>());

    InitializedEntity Entity;
    Entity.Kind = EK_Parameter;
    Entity.Type =
      Context.getVariableArrayDecayedType(Type.getUnqualifiedType());
    Entity.Parent = nullptr;
    Entity.Parameter = {Parm, Consumed};
    return Entity;
  }

  /// Create the initialization entity for a parameter that is
  /// only known by its type.
  static InitializedEntity InitializeParameter(ASTContext &Context,
                                               QualType Type,
                                               bool Consumed) {
    InitializedEntity Entity;
    Entity.Kind = EK_Parameter;
    Entity.Type = Context.getVariableArrayDecayedType(Type);
    Entity.Parent = nullptr;
    Entity.Parameter = {nullptr, Consumed};
    return Entity;
  }

  /// Create the initialization entity for a template parameter.
  static InitializedEntity
  InitializeTemplateParameter(QualType T, NonTypeTemplateParmDecl *Param) {
    InitializedEntity Entity;
    Entity.Kind = EK_TemplateParameter;
    Entity.Type = T;
    Entity.Parent = nullptr;
    Entity.Variable = {Param, false, false};
    return Entity;
  }

  /// Create the initialization entity for the result of a function.
  static InitializedEntity InitializeResult(SourceLocation ReturnLoc,
                                            QualType Type, bool NRVO) {
    return InitializedEntity(EK_Result, ReturnLoc, Type, NRVO);
  }

  static InitializedEntity InitializeStmtExprResult(SourceLocation ReturnLoc,
                                            QualType Type) {
    return InitializedEntity(EK_StmtExprResult, ReturnLoc, Type);
  }

  static InitializedEntity InitializeBlock(SourceLocation BlockVarLoc,
                                           QualType Type, bool NRVO) {
    return InitializedEntity(EK_BlockElement, BlockVarLoc, Type, NRVO);
  }

  static InitializedEntity InitializeLambdaToBlock(SourceLocation BlockVarLoc,
                                                   QualType Type, bool NRVO) {
    return InitializedEntity(EK_LambdaToBlockConversionBlockElement,
                             BlockVarLoc, Type, NRVO);
  }

  /// Create the initialization entity for an exception object.
  static InitializedEntity InitializeException(SourceLocation ThrowLoc,
                                               QualType Type, bool NRVO) {
    return InitializedEntity(EK_Exception, ThrowLoc, Type, NRVO);
  }

  /// Create the initialization entity for an object allocated via new.
  static InitializedEntity InitializeNew(SourceLocation NewLoc, QualType Type) {
    return InitializedEntity(EK_New, NewLoc, Type);
  }

  /// Create the initialization entity for a temporary.
  static InitializedEntity InitializeTemporary(QualType Type) {
    return InitializeTemporary(nullptr, Type);
  }

  /// Create the initialization entity for a temporary.
  static InitializedEntity InitializeTemporary(TypeSourceInfo *TypeInfo) {
    return InitializeTemporary(TypeInfo, TypeInfo->getType());
  }

  /// Create the initialization entity for a temporary.
  static InitializedEntity InitializeTemporary(TypeSourceInfo *TypeInfo,
                                               QualType Type) {
    InitializedEntity Result(EK_Temporary, SourceLocation(), Type);
    Result.TypeInfo = TypeInfo;
    return Result;
  }

  /// Create the initialization entity for a related result.
  static InitializedEntity InitializeRelatedResult(ObjCMethodDecl *MD,
                                                   QualType Type) {
    InitializedEntity Result(EK_RelatedResult, SourceLocation(), Type);
    Result.MethodDecl = MD;
    return Result;
  }

  /// Create the initialization entity for a base class subobject.
  static InitializedEntity
  InitializeBase(ASTContext &Context, const CXXBaseSpecifier *Base,
                 bool IsInheritedVirtualBase,
                 const InitializedEntity *Parent = nullptr);

  /// Create the initialization entity for a delegated constructor.
  static InitializedEntity InitializeDelegation(QualType Type) {
    return InitializedEntity(EK_Delegating, SourceLocation(), Type);
  }

  /// Create the initialization entity for a member subobject.
  static InitializedEntity
  InitializeMember(FieldDecl *Member,
                   const InitializedEntity *Parent = nullptr,
                   bool Implicit = false) {
    return InitializedEntity(Member, Parent, Implicit, false);
  }

  /// Create the initialization entity for a member subobject.
  static InitializedEntity
  InitializeMember(IndirectFieldDecl *Member,
                   const InitializedEntity *Parent = nullptr,
                   bool Implicit = false) {
    return InitializedEntity(Member->getAnonField(), Parent, Implicit, false);
  }

  /// Create the initialization entity for a default member initializer.
  static InitializedEntity
  InitializeMemberFromDefaultMemberInitializer(FieldDecl *Member) {
    return InitializedEntity(Member, nullptr, false, true);
  }

  /// Create the initialization entity for an array element.
  static InitializedEntity InitializeElement(ASTContext &Context,
                                             unsigned Index,
                                             const InitializedEntity &Parent) {
    return InitializedEntity(Context, Index, Parent);
  }

  /// Create the initialization entity for a structured binding.
  static InitializedEntity InitializeBinding(VarDecl *Binding) {
    return InitializedEntity(Binding, EK_Binding);
  }

  /// Create the initialization entity for a lambda capture.
  ///
  /// \p VarID The name of the entity being captured, or nullptr for 'this'.
  static InitializedEntity InitializeLambdaCapture(IdentifierInfo *VarID,
                                                   QualType FieldType,
                                                   SourceLocation Loc) {
    return InitializedEntity(VarID, FieldType, Loc);
  }

  /// Create the entity for a compound literal initializer.
  static InitializedEntity InitializeCompoundLiteralInit(TypeSourceInfo *TSI) {
    InitializedEntity Result(EK_CompoundLiteralInit, SourceLocation(),
                             TSI->getType());
    Result.TypeInfo = TSI;
    return Result;
  }

  /// Determine the kind of initialization.
  EntityKind getKind() const { return Kind; }

  /// Retrieve the parent of the entity being initialized, when
  /// the initialization itself is occurring within the context of a
  /// larger initialization.
  const InitializedEntity *getParent() const { return Parent; }

  /// Retrieve type being initialized.
  QualType getType() const { return Type; }

  /// Retrieve complete type-source information for the object being
  /// constructed, if known.
  TypeSourceInfo *getTypeSourceInfo() const {
    if (Kind == EK_Temporary || Kind == EK_CompoundLiteralInit)
      return TypeInfo;

    return nullptr;
  }

  /// Retrieve the name of the entity being initialized.
  DeclarationName getName() const;

  /// Retrieve the variable, parameter, or field being
  /// initialized.
  ValueDecl *getDecl() const;

  /// Retrieve the ObjectiveC method being initialized.
  ObjCMethodDecl *getMethodDecl() const { return MethodDecl; }

  /// Determine whether this initialization allows the named return
  /// value optimization, which also applies to thrown objects.
  bool allowsNRVO() const;

  bool isParameterKind() const {
    return (getKind() == EK_Parameter  ||
            getKind() == EK_Parameter_CF_Audited);
  }

  bool isParamOrTemplateParamKind() const {
    return isParameterKind() || getKind() == EK_TemplateParameter;
  }

  /// Determine whether this initialization consumes the
  /// parameter.
  bool isParameterConsumed() const {
    assert(isParameterKind() && "Not a parameter");
    return Parameter.getInt();
  }

  /// Retrieve the base specifier.
  const CXXBaseSpecifier *getBaseSpecifier() const {
    assert(getKind() == EK_Base && "Not a base specifier");
    return Base.getPointer();
  }

  /// Return whether the base is an inherited virtual base.
  bool isInheritedVirtualBase() const {
    assert(getKind() == EK_Base && "Not a base specifier");
    return Base.getInt();
  }

  /// Determine whether this is an array new with an unknown bound.
  bool isVariableLengthArrayNew() const {
    return getKind() == EK_New && dyn_cast_or_null<IncompleteArrayType>(
                                      getType()->getAsArrayTypeUnsafe());
  }

  /// Is this the implicit initialization of a member of a class from
  /// a defaulted constructor?
  bool isImplicitMemberInitializer() const {
    return getKind() == EK_Member && Variable.IsImplicitFieldInit;
  }

  /// Is this the default member initializer of a member (specified inside
  /// the class definition)?
  bool isDefaultMemberInitializer() const {
    return getKind() == EK_Member && Variable.IsDefaultMemberInit;
  }

  /// Determine the location of the 'return' keyword when initializing
  /// the result of a function call.
  SourceLocation getReturnLoc() const {
    assert(getKind() == EK_Result && "No 'return' location!");
    return LocAndNRVO.Location;
  }

  /// Determine the location of the 'throw' keyword when initializing
  /// an exception object.
  SourceLocation getThrowLoc() const {
    assert(getKind() == EK_Exception && "No 'throw' location!");
    return LocAndNRVO.Location;
  }

  /// If this is an array, vector, or complex number element, get the
  /// element's index.
  unsigned getElementIndex() const {
    assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
           getKind() == EK_ComplexElement);
    return Index;
  }

  /// If this is already the initializer for an array or vector
  /// element, sets the element index.
  void setElementIndex(unsigned Index) {
    assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
           getKind() == EK_ComplexElement);
    this->Index = Index;
  }

  /// For a lambda capture, return the capture's name.
  StringRef getCapturedVarName() const {
    assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
    return Capture.VarID ? Capture.VarID->getName() : "this";
  }

  /// Determine the location of the capture when initializing
  /// field from a captured variable in a lambda.
  SourceLocation getCaptureLoc() const {
    assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
    return Capture.Location;
  }

  void setParameterCFAudited() {
    Kind = EK_Parameter_CF_Audited;
  }

  unsigned allocateManglingNumber() const { return ++ManglingNumber; }

  /// Dump a representation of the initialized entity to standard error,
  /// for debugging purposes.
  void dump() const;

private:
  unsigned dumpImpl(raw_ostream &OS) const;
};

/// Describes the kind of initialization being performed, along with
/// location information for tokens related to the initialization (equal sign,
/// parentheses).
class InitializationKind {
public:
  /// The kind of initialization being performed.
  enum InitKind {
    /// Direct initialization
    IK_Direct,

    /// Direct list-initialization
    IK_DirectList,

    /// Copy initialization
    IK_Copy,

    /// Default initialization
    IK_Default,

    /// Value initialization
    IK_Value
  };

private:
  /// The context of the initialization.
  enum InitContext {
    /// Normal context
    IC_Normal,

    /// Normal context, but allows explicit conversion functionss
    IC_ExplicitConvs,

    /// Implicit context (value initialization)
    IC_Implicit,

    /// Static cast context
    IC_StaticCast,

    /// C-style cast context
    IC_CStyleCast,

    /// Functional cast context
    IC_FunctionalCast
  };

  /// The kind of initialization being performed.
  InitKind Kind : 8;

  /// The context of the initialization.
  InitContext Context : 8;

  /// The source locations involved in the initialization.
  SourceLocation Locations[3];

  InitializationKind(InitKind Kind, InitContext Context, SourceLocation Loc1,
                     SourceLocation Loc2, SourceLocation Loc3)
      : Kind(Kind), Context(Context) {
    Locations[0] = Loc1;
    Locations[1] = Loc2;
    Locations[2] = Loc3;
  }

public:
  /// Create a direct initialization.
  static InitializationKind CreateDirect(SourceLocation InitLoc,
                                         SourceLocation LParenLoc,
                                         SourceLocation RParenLoc) {
    return InitializationKind(IK_Direct, IC_Normal,
                              InitLoc, LParenLoc, RParenLoc);
  }

  static InitializationKind CreateDirectList(SourceLocation InitLoc) {
    return InitializationKind(IK_DirectList, IC_Normal, InitLoc, InitLoc,
                              InitLoc);
  }

  static InitializationKind CreateDirectList(SourceLocation InitLoc,
                                             SourceLocation LBraceLoc,
                                             SourceLocation RBraceLoc) {
    return InitializationKind(IK_DirectList, IC_Normal, InitLoc, LBraceLoc,
                              RBraceLoc);
  }

  /// Create a direct initialization due to a cast that isn't a C-style
  /// or functional cast.
  static InitializationKind CreateCast(SourceRange TypeRange) {
    return InitializationKind(IK_Direct, IC_StaticCast, TypeRange.getBegin(),
                              TypeRange.getBegin(), TypeRange.getEnd());
  }

  /// Create a direct initialization for a C-style cast.
  static InitializationKind CreateCStyleCast(SourceLocation StartLoc,
                                             SourceRange TypeRange,
                                             bool InitList) {
    // C++ cast syntax doesn't permit init lists, but C compound literals are
    // exactly that.
    return InitializationKind(InitList ? IK_DirectList : IK_Direct,
                              IC_CStyleCast, StartLoc, TypeRange.getBegin(),
                              TypeRange.getEnd());
  }

  /// Create a direct initialization for a functional cast.
  static InitializationKind CreateFunctionalCast(SourceRange TypeRange,
                                                 bool InitList) {
    return InitializationKind(InitList ? IK_DirectList : IK_Direct,
                              IC_FunctionalCast, TypeRange.getBegin(),
                              TypeRange.getBegin(), TypeRange.getEnd());
  }

  /// Create a copy initialization.
  static InitializationKind CreateCopy(SourceLocation InitLoc,
                                       SourceLocation EqualLoc,
                                       bool AllowExplicitConvs = false) {
    return InitializationKind(IK_Copy,
                              AllowExplicitConvs? IC_ExplicitConvs : IC_Normal,
                              InitLoc, EqualLoc, EqualLoc);
  }

  /// Create a default initialization.
  static InitializationKind CreateDefault(SourceLocation InitLoc) {
    return InitializationKind(IK_Default, IC_Normal, InitLoc, InitLoc, InitLoc);
  }

  /// Create a value initialization.
  static InitializationKind CreateValue(SourceLocation InitLoc,
                                        SourceLocation LParenLoc,
                                        SourceLocation RParenLoc,
                                        bool isImplicit = false) {
    return InitializationKind(IK_Value, isImplicit ? IC_Implicit : IC_Normal,
                              InitLoc, LParenLoc, RParenLoc);
  }

  /// Create an initialization from an initializer (which, for direct
  /// initialization from a parenthesized list, will be a ParenListExpr).
  static InitializationKind CreateForInit(SourceLocation Loc, bool DirectInit,
                                          Expr *Init) {
    if (!Init) return CreateDefault(Loc);
    if (!DirectInit)
      return CreateCopy(Loc, Init->getBeginLoc());
    if (isa<InitListExpr>(Init))
      return CreateDirectList(Loc, Init->getBeginLoc(), Init->getEndLoc());
    return CreateDirect(Loc, Init->getBeginLoc(), Init->getEndLoc());
  }

  /// Determine the initialization kind.
  InitKind getKind() const {
    return Kind;
  }

  /// Determine whether this initialization is an explicit cast.
  bool isExplicitCast() const {
    return Context >= IC_StaticCast;
  }

  /// Determine whether this initialization is a static cast.
  bool isStaticCast() const { return Context == IC_StaticCast; }

  /// Determine whether this initialization is a C-style cast.
  bool isCStyleOrFunctionalCast() const {
    return Context >= IC_CStyleCast;
  }

  /// Determine whether this is a C-style cast.
  bool isCStyleCast() const {
    return Context == IC_CStyleCast;
  }

  /// Determine whether this is a functional-style cast.
  bool isFunctionalCast() const {
    return Context == IC_FunctionalCast;
  }

  /// Determine whether this initialization is an implicit
  /// value-initialization, e.g., as occurs during aggregate
  /// initialization.
  bool isImplicitValueInit() const { return Context == IC_Implicit; }

  /// Retrieve the location at which initialization is occurring.
  SourceLocation getLocation() const { return Locations[0]; }

  /// Retrieve the source range that covers the initialization.
  SourceRange getRange() const {
    return SourceRange(Locations[0], Locations[2]);
  }

  /// Retrieve the location of the equal sign for copy initialization
  /// (if present).
  SourceLocation getEqualLoc() const {
    assert(Kind == IK_Copy && "Only copy initialization has an '='");
    return Locations[1];
  }

  bool isCopyInit() const { return Kind == IK_Copy; }

  /// Retrieve whether this initialization allows the use of explicit
  ///        constructors.
  bool AllowExplicit() const { return !isCopyInit(); }

  /// Retrieve whether this initialization allows the use of explicit
  /// conversion functions when binding a reference. If the reference is the
  /// first parameter in a copy or move constructor, such conversions are
  /// permitted even though we are performing copy-initialization.
  bool allowExplicitConversionFunctionsInRefBinding() const {
    return !isCopyInit() || Context == IC_ExplicitConvs;
  }

  /// Determine whether this initialization has a source range containing the
  /// locations of open and closing parentheses or braces.
  bool hasParenOrBraceRange() const {
    return Kind == IK_Direct || Kind == IK_Value || Kind == IK_DirectList;
  }

  /// Retrieve the source range containing the locations of the open
  /// and closing parentheses or braces for value, direct, and direct list
  /// initializations.
  SourceRange getParenOrBraceRange() const {
    assert(hasParenOrBraceRange() && "Only direct, value, and direct-list "
                                     "initialization have parentheses or "
                                     "braces");
    return SourceRange(Locations[1], Locations[2]);
  }
};

/// Describes the sequence of initializations required to initialize
/// a given object or reference with a set of arguments.
class InitializationSequence {
public:
  /// Describes the kind of initialization sequence computed.
  enum SequenceKind {
    /// A failed initialization sequence. The failure kind tells what
    /// happened.
    FailedSequence = 0,

    /// A dependent initialization, which could not be
    /// type-checked due to the presence of dependent types or
    /// dependently-typed expressions.
    DependentSequence,

    /// A normal sequence.
    NormalSequence
  };

  /// Describes the kind of a particular step in an initialization
  /// sequence.
  enum StepKind {
    /// Resolve the address of an overloaded function to a specific
    /// function declaration.
    SK_ResolveAddressOfOverloadedFunction,

    /// Perform a derived-to-base cast, producing an rvalue.
    SK_CastDerivedToBasePRValue,

    /// Perform a derived-to-base cast, producing an xvalue.
    SK_CastDerivedToBaseXValue,

    /// Perform a derived-to-base cast, producing an lvalue.
    SK_CastDerivedToBaseLValue,

    /// Reference binding to an lvalue.
    SK_BindReference,

    /// Reference binding to a temporary.
    SK_BindReferenceToTemporary,

    /// An optional copy of a temporary object to another
    /// temporary object, which is permitted (but not required) by
    /// C++98/03 but not C++0x.
    SK_ExtraneousCopyToTemporary,

    /// Direct-initialization from a reference-related object in the
    /// final stage of class copy-initialization.
    SK_FinalCopy,

    /// Perform a user-defined conversion, either via a conversion
    /// function or via a constructor.
    SK_UserConversion,

    /// Perform a qualification conversion, producing a prvalue.
    SK_QualificationConversionPRValue,

    /// Perform a qualification conversion, producing an xvalue.
    SK_QualificationConversionXValue,

    /// Perform a qualification conversion, producing an lvalue.
    SK_QualificationConversionLValue,

    /// Perform a function reference conversion, see [dcl.init.ref]p4.
    SK_FunctionReferenceConversion,

    /// Perform a conversion adding _Atomic to a type.
    SK_AtomicConversion,

    /// Perform an implicit conversion sequence.
    SK_ConversionSequence,

    /// Perform an implicit conversion sequence without narrowing.
    SK_ConversionSequenceNoNarrowing,

    /// Perform list-initialization without a constructor.
    SK_ListInitialization,

    /// Unwrap the single-element initializer list for a reference.
    SK_UnwrapInitList,

    /// Rewrap the single-element initializer list for a reference.
    SK_RewrapInitList,

    /// Perform initialization via a constructor.
    SK_ConstructorInitialization,

    /// Perform initialization via a constructor, taking arguments from
    /// a single InitListExpr.
    SK_ConstructorInitializationFromList,

    /// Zero-initialize the object
    SK_ZeroInitialization,

    /// C assignment
    SK_CAssignment,

    /// Initialization by string
    SK_StringInit,

    /// An initialization that "converts" an Objective-C object
    /// (not a point to an object) to another Objective-C object type.
    SK_ObjCObjectConversion,

    /// Array indexing for initialization by elementwise copy.
    SK_ArrayLoopIndex,

    /// Array initialization by elementwise copy.
    SK_ArrayLoopInit,

    /// Array initialization (from an array rvalue).
    SK_ArrayInit,

    /// Array initialization (from an array rvalue) as a GNU extension.
    SK_GNUArrayInit,

    /// Array initialization from a parenthesized initializer list.
    /// This is a GNU C++ extension.
    SK_ParenthesizedArrayInit,

    /// Pass an object by indirect copy-and-restore.
    SK_PassByIndirectCopyRestore,

    /// Pass an object by indirect restore.
    SK_PassByIndirectRestore,

    /// Produce an Objective-C object pointer.
    SK_ProduceObjCObject,

    /// Construct a std::initializer_list from an initializer list.
    SK_StdInitializerList,

    /// Perform initialization via a constructor taking a single
    /// std::initializer_list argument.
    SK_StdInitializerListConstructorCall,

    /// Initialize an OpenCL sampler from an integer.
    SK_OCLSamplerInit,

    /// Initialize an opaque OpenCL type (event_t, queue_t, etc.) with zero
    SK_OCLZeroOpaqueType
  };

  /// A single step in the initialization sequence.
  class Step {
  public:
    /// The kind of conversion or initialization step we are taking.
    StepKind Kind;

    // The type that results from this initialization.
    QualType Type;

    struct F {
      bool HadMultipleCandidates;
      FunctionDecl *Function;
      DeclAccessPair FoundDecl;
    };

    union {
      /// When Kind == SK_ResolvedOverloadedFunction or Kind ==
      /// SK_UserConversion, the function that the expression should be
      /// resolved to or the conversion function to call, respectively.
      /// When Kind == SK_ConstructorInitialization or SK_ListConstruction,
      /// the constructor to be called.
      ///
      /// Always a FunctionDecl, plus a Boolean flag telling if it was
      /// selected from an overloaded set having size greater than 1.
      /// For conversion decls, the naming class is the source type.
      /// For construct decls, the naming class is the target type.
      struct F Function;

      /// When Kind = SK_ConversionSequence, the implicit conversion
      /// sequence.
      ImplicitConversionSequence *ICS;

      /// When Kind = SK_RewrapInitList, the syntactic form of the
      /// wrapping list.
      InitListExpr *WrappingSyntacticList;
    };

    void Destroy();
  };

private:
  /// The kind of initialization sequence computed.
  enum SequenceKind SequenceKind;

  /// Steps taken by this initialization.
  SmallVector<Step, 4> Steps;

public:
  /// Describes why initialization failed.
  enum FailureKind {
    /// Too many initializers provided for a reference.
    FK_TooManyInitsForReference,

    /// Reference initialized from a parenthesized initializer list.
    FK_ParenthesizedListInitForReference,

    /// Array must be initialized with an initializer list.
    FK_ArrayNeedsInitList,

    /// Array must be initialized with an initializer list or a
    /// string literal.
    FK_ArrayNeedsInitListOrStringLiteral,

    /// Array must be initialized with an initializer list or a
    /// wide string literal.
    FK_ArrayNeedsInitListOrWideStringLiteral,

    /// Initializing a wide char array with narrow string literal.
    FK_NarrowStringIntoWideCharArray,

    /// Initializing char array with wide string literal.
    FK_WideStringIntoCharArray,

    /// Initializing wide char array with incompatible wide string
    /// literal.
    FK_IncompatWideStringIntoWideChar,

    /// Initializing char8_t array with plain string literal.
    FK_PlainStringIntoUTF8Char,

    /// Initializing char array with UTF-8 string literal.
    FK_UTF8StringIntoPlainChar,

    /// Array type mismatch.
    FK_ArrayTypeMismatch,

    /// Non-constant array initializer
    FK_NonConstantArrayInit,

    /// Cannot resolve the address of an overloaded function.
    FK_AddressOfOverloadFailed,

    /// Overloading due to reference initialization failed.
    FK_ReferenceInitOverloadFailed,

    /// Non-const lvalue reference binding to a temporary.
    FK_NonConstLValueReferenceBindingToTemporary,

    /// Non-const lvalue reference binding to a bit-field.
    FK_NonConstLValueReferenceBindingToBitfield,

    /// Non-const lvalue reference binding to a vector element.
    FK_NonConstLValueReferenceBindingToVectorElement,

    /// Non-const lvalue reference binding to a matrix element.
    FK_NonConstLValueReferenceBindingToMatrixElement,

    /// Non-const lvalue reference binding to an lvalue of unrelated
    /// type.
    FK_NonConstLValueReferenceBindingToUnrelated,

    /// Rvalue reference binding to an lvalue.
    FK_RValueReferenceBindingToLValue,

    /// Reference binding drops qualifiers.
    FK_ReferenceInitDropsQualifiers,

    /// Reference with mismatching address space binding to temporary.
    FK_ReferenceAddrspaceMismatchTemporary,

    /// Reference binding failed.
    FK_ReferenceInitFailed,

    /// Implicit conversion failed.
    FK_ConversionFailed,

    /// Implicit conversion failed.
    FK_ConversionFromPropertyFailed,

    /// Too many initializers for scalar
    FK_TooManyInitsForScalar,

    /// Scalar initialized from a parenthesized initializer list.
    FK_ParenthesizedListInitForScalar,

    /// Reference initialization from an initializer list
    FK_ReferenceBindingToInitList,

    /// Initialization of some unused destination type with an
    /// initializer list.
    FK_InitListBadDestinationType,

    /// Overloading for a user-defined conversion failed.
    FK_UserConversionOverloadFailed,

    /// Overloading for initialization by constructor failed.
    FK_ConstructorOverloadFailed,

    /// Overloading for list-initialization by constructor failed.
    FK_ListConstructorOverloadFailed,

    /// Default-initialization of a 'const' object.
    FK_DefaultInitOfConst,

    /// Initialization of an incomplete type.
    FK_Incomplete,

    /// Variable-length array must not have an initializer.
    FK_VariableLengthArrayHasInitializer,

    /// List initialization failed at some point.
    FK_ListInitializationFailed,

    /// Initializer has a placeholder type which cannot be
    /// resolved by initialization.
    FK_PlaceholderType,

    /// Trying to take the address of a function that doesn't support
    /// having its address taken.
    FK_AddressOfUnaddressableFunction,

    /// List-copy-initialization chose an explicit constructor.
    FK_ExplicitConstructor,
  };

private:
  /// The reason why initialization failed.
  FailureKind Failure;

  /// The failed result of overload resolution.
  OverloadingResult FailedOverloadResult;

  /// The candidate set created when initialization failed.
  OverloadCandidateSet FailedCandidateSet;

  /// The incomplete type that caused a failure.
  QualType FailedIncompleteType;

  /// The fixit that needs to be applied to make this initialization
  /// succeed.
  std::string ZeroInitializationFixit;
  SourceLocation ZeroInitializationFixitLoc;

public:
  /// Call for initializations are invalid but that would be valid
  /// zero initialzations if Fixit was applied.
  void SetZeroInitializationFixit(const std::string& Fixit, SourceLocation L) {
    ZeroInitializationFixit = Fixit;
    ZeroInitializationFixitLoc = L;
  }

private:
  /// Prints a follow-up note that highlights the location of
  /// the initialized entity, if it's remote.
  void PrintInitLocationNote(Sema &S, const InitializedEntity &Entity);

public:
  /// Try to perform initialization of the given entity, creating a
  /// record of the steps required to perform the initialization.
  ///
  /// The generated initialization sequence will either contain enough
  /// information to diagnose
  ///
  /// \param S the semantic analysis object.
  ///
  /// \param Entity the entity being initialized.
  ///
  /// \param Kind the kind of initialization being performed.
  ///
  /// \param Args the argument(s) provided for initialization.
  ///
  /// \param TopLevelOfInitList true if we are initializing from an expression
  ///        at the top level inside an initializer list. This disallows
  ///        narrowing conversions in C++11 onwards.
  /// \param TreatUnavailableAsInvalid true if we want to treat unavailable
  ///        as invalid.
  InitializationSequence(Sema &S,
                         const InitializedEntity &Entity,
                         const InitializationKind &Kind,
                         MultiExprArg Args,
                         bool TopLevelOfInitList = false,
                         bool TreatUnavailableAsInvalid = true);
  void InitializeFrom(Sema &S, const InitializedEntity &Entity,
                      const InitializationKind &Kind, MultiExprArg Args,
                      bool TopLevelOfInitList, bool TreatUnavailableAsInvalid);

  ~InitializationSequence();

  /// Perform the actual initialization of the given entity based on
  /// the computed initialization sequence.
  ///
  /// \param S the semantic analysis object.
  ///
  /// \param Entity the entity being initialized.
  ///
  /// \param Kind the kind of initialization being performed.
  ///
  /// \param Args the argument(s) provided for initialization, ownership of
  /// which is transferred into the routine.
  ///
  /// \param ResultType if non-NULL, will be set to the type of the
  /// initialized object, which is the type of the declaration in most
  /// cases. However, when the initialized object is a variable of
  /// incomplete array type and the initializer is an initializer
  /// list, this type will be set to the completed array type.
  ///
  /// \returns an expression that performs the actual object initialization, if
  /// the initialization is well-formed. Otherwise, emits diagnostics
  /// and returns an invalid expression.
  ExprResult Perform(Sema &S,
                     const InitializedEntity &Entity,
                     const InitializationKind &Kind,
                     MultiExprArg Args,
                     QualType *ResultType = nullptr);

  /// Diagnose an potentially-invalid initialization sequence.
  ///
  /// \returns true if the initialization sequence was ill-formed,
  /// false otherwise.
  bool Diagnose(Sema &S,
                const InitializedEntity &Entity,
                const InitializationKind &Kind,
                ArrayRef<Expr *> Args);

  /// Determine the kind of initialization sequence computed.
  enum SequenceKind getKind() const { return SequenceKind; }

  /// Set the kind of sequence computed.
  void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; }

  /// Determine whether the initialization sequence is valid.
  explicit operator bool() const { return !Failed(); }

  /// Determine whether the initialization sequence is invalid.
  bool Failed() const { return SequenceKind == FailedSequence; }

  using step_iterator = SmallVectorImpl<Step>::const_iterator;

  step_iterator step_begin() const { return Steps.begin(); }
  step_iterator step_end()   const { return Steps.end(); }

  using step_range = llvm::iterator_range<step_iterator>;

  step_range steps() const { return {step_begin(), step_end()}; }

  /// Determine whether this initialization is a direct reference
  /// binding (C++ [dcl.init.ref]).
  bool isDirectReferenceBinding() const;

  /// Determine whether this initialization failed due to an ambiguity.
  bool isAmbiguous() const;

  /// Determine whether this initialization is direct call to a
  /// constructor.
  bool isConstructorInitialization() const;

  /// Add a new step in the initialization that resolves the address
  /// of an overloaded function to a specific function declaration.
  ///
  /// \param Function the function to which the overloaded function reference
  /// resolves.
  void AddAddressOverloadResolutionStep(FunctionDecl *Function,
                                        DeclAccessPair Found,
                                        bool HadMultipleCandidates);

  /// Add a new step in the initialization that performs a derived-to-
  /// base cast.
  ///
  /// \param BaseType the base type to which we will be casting.
  ///
  /// \param Category Indicates whether the result will be treated as an
  /// rvalue, an xvalue, or an lvalue.
  void AddDerivedToBaseCastStep(QualType BaseType,
                                ExprValueKind Category);

  /// Add a new step binding a reference to an object.
  ///
  /// \param BindingTemporary True if we are binding a reference to a temporary
  /// object (thereby extending its lifetime); false if we are binding to an
  /// lvalue or an lvalue treated as an rvalue.
  void AddReferenceBindingStep(QualType T, bool BindingTemporary);

  /// Add a new step that makes an extraneous copy of the input
  /// to a temporary of the same class type.
  ///
  /// This extraneous copy only occurs during reference binding in
  /// C++98/03, where we are permitted (but not required) to introduce
  /// an extra copy. At a bare minimum, we must check that we could
  /// call the copy constructor, and produce a diagnostic if the copy
  /// constructor is inaccessible or no copy constructor matches.
  //
  /// \param T The type of the temporary being created.
  void AddExtraneousCopyToTemporary(QualType T);

  /// Add a new step that makes a copy of the input to an object of
  /// the given type, as the final step in class copy-initialization.
  void AddFinalCopy(QualType T);

  /// Add a new step invoking a conversion function, which is either
  /// a constructor or a conversion function.
  void AddUserConversionStep(FunctionDecl *Function,
                             DeclAccessPair FoundDecl,
                             QualType T,
                             bool HadMultipleCandidates);

  /// Add a new step that performs a qualification conversion to the
  /// given type.
  void AddQualificationConversionStep(QualType Ty,
                                     ExprValueKind Category);

  /// Add a new step that performs a function reference conversion to the
  /// given type.
  void AddFunctionReferenceConversionStep(QualType Ty);

  /// Add a new step that performs conversion from non-atomic to atomic
  /// type.
  void AddAtomicConversionStep(QualType Ty);

  /// Add a new step that applies an implicit conversion sequence.
  void AddConversionSequenceStep(const ImplicitConversionSequence &ICS,
                                 QualType T, bool TopLevelOfInitList = false);

  /// Add a list-initialization step.
  void AddListInitializationStep(QualType T);

  /// Add a constructor-initialization step.
  ///
  /// \param FromInitList The constructor call is syntactically an initializer
  /// list.
  /// \param AsInitList The constructor is called as an init list constructor.
  void AddConstructorInitializationStep(DeclAccessPair FoundDecl,
                                        CXXConstructorDecl *Constructor,
                                        QualType T,
                                        bool HadMultipleCandidates,
                                        bool FromInitList, bool AsInitList);

  /// Add a zero-initialization step.
  void AddZeroInitializationStep(QualType T);

  /// Add a C assignment step.
  //
  // FIXME: It isn't clear whether this should ever be needed;
  // ideally, we would handle everything needed in C in the common
  // path. However, that isn't the case yet.
  void AddCAssignmentStep(QualType T);

  /// Add a string init step.
  void AddStringInitStep(QualType T);

  /// Add an Objective-C object conversion step, which is
  /// always a no-op.
  void AddObjCObjectConversionStep(QualType T);

  /// Add an array initialization loop step.
  void AddArrayInitLoopStep(QualType T, QualType EltTy);

  /// Add an array initialization step.
  void AddArrayInitStep(QualType T, bool IsGNUExtension);

  /// Add a parenthesized array initialization step.
  void AddParenthesizedArrayInitStep(QualType T);

  /// Add a step to pass an object by indirect copy-restore.
  void AddPassByIndirectCopyRestoreStep(QualType T, bool shouldCopy);

  /// Add a step to "produce" an Objective-C object (by
  /// retaining it).
  void AddProduceObjCObjectStep(QualType T);

  /// Add a step to construct a std::initializer_list object from an
  /// initializer list.
  void AddStdInitializerListConstructionStep(QualType T);

  /// Add a step to initialize an OpenCL sampler from an integer
  /// constant.
  void AddOCLSamplerInitStep(QualType T);

  /// Add a step to initialzie an OpenCL opaque type (event_t, queue_t, etc.)
  /// from a zero constant.
  void AddOCLZeroOpaqueTypeStep(QualType T);

  /// Add steps to unwrap a initializer list for a reference around a
  /// single element and rewrap it at the end.
  void RewrapReferenceInitList(QualType T, InitListExpr *Syntactic);

  /// Note that this initialization sequence failed.
  void SetFailed(FailureKind Failure) {
    SequenceKind = FailedSequence;
    this->Failure = Failure;
    assert((Failure != FK_Incomplete || !FailedIncompleteType.isNull()) &&
           "Incomplete type failure requires a type!");
  }

  /// Note that this initialization sequence failed due to failed
  /// overload resolution.
  void SetOverloadFailure(FailureKind Failure, OverloadingResult Result);

  /// Retrieve a reference to the candidate set when overload
  /// resolution fails.
  OverloadCandidateSet &getFailedCandidateSet() {
    return FailedCandidateSet;
  }

  /// Get the overloading result, for when the initialization
  /// sequence failed due to a bad overload.
  OverloadingResult getFailedOverloadResult() const {
    return FailedOverloadResult;
  }

  /// Note that this initialization sequence failed due to an
  /// incomplete type.
  void setIncompleteTypeFailure(QualType IncompleteType) {
    FailedIncompleteType = IncompleteType;
    SetFailed(FK_Incomplete);
  }

  /// Determine why initialization failed.
  FailureKind getFailureKind() const {
    assert(Failed() && "Not an initialization failure!");
    return Failure;
  }

  /// Dump a representation of this initialization sequence to
  /// the given stream, for debugging purposes.
  void dump(raw_ostream &OS) const;

  /// Dump a representation of this initialization sequence to
  /// standard error, for debugging purposes.
  void dump() const;
};

} // namespace clang

#endif // LLVM_CLANG_SEMA_INITIALIZATION_H