aboutsummaryrefslogtreecommitdiff
path: root/gcc/cp/rtti.c
blob: a8e6d25c844428dbb7156d5aec07cc4c8147c5cf (plain)
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
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
/* RunTime Type Identification
   Copyright (C) 1995-2014 Free Software Foundation, Inc.
   Mostly written by Jason Merrill (jason@cygnus.com).

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "intl.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "stringpool.h"
#include "stor-layout.h"
#include "cp-tree.h"
#include "flags.h"
#include "convert.h"
#include "target.h"
#include "c-family/c-pragma.h"

/* C++ returns type information to the user in struct type_info
   objects. We also use type information to implement dynamic_cast and
   exception handlers. Type information for a particular type is
   indicated with an ABI defined structure derived from type_info.
   This would all be very straight forward, but for the fact that the
   runtime library provides the definitions of the type_info structure
   and the ABI defined derived classes. We cannot build declarations
   of them directly in the compiler, but we need to layout objects of
   their type.  Somewhere we have to lie.

   We define layout compatible POD-structs with compiler-defined names
   and generate the appropriate initializations for them (complete
   with explicit mention of their vtable). When we have to provide a
   type_info to the user we reinterpret_cast the internal compiler
   type to type_info.  A well formed program can only explicitly refer
   to the type_infos of complete types (& cv void).  However, we chain
   pointer type_infos to the pointed-to-type, and that can be
   incomplete.  We only need the addresses of such incomplete
   type_info objects for static initialization.

   The type information VAR_DECL of a type is held on the
   IDENTIFIER_GLOBAL_VALUE of the type's mangled name. That VAR_DECL
   will be the internal type.  It will usually have the correct
   internal type reflecting the kind of type it represents (pointer,
   array, function, class, inherited class, etc).  When the type it
   represents is incomplete, it will have the internal type
   corresponding to type_info.  That will only happen at the end of
   translation, when we are emitting the type info objects.  */

/* Auxiliary data we hold for each type_info derived object we need.  */
typedef struct GTY (()) tinfo_s {
  tree type;  /* The RECORD_TYPE for this type_info object */

  tree vtable; /* The VAR_DECL of the vtable.  Only filled at end of
		  translation.  */

  tree name;  /* IDENTIFIER_NODE for the ABI specified name of
		 the type_info derived type.  */
} tinfo_s;


typedef enum tinfo_kind
{
  TK_TYPE_INFO_TYPE,    /* abi::__type_info_pseudo */
  TK_BASE_TYPE,		/* abi::__base_class_type_info */
  TK_BUILTIN_TYPE,	/* abi::__fundamental_type_info */
  TK_ARRAY_TYPE,	/* abi::__array_type_info */
  TK_FUNCTION_TYPE,	/* abi::__function_type_info */
  TK_ENUMERAL_TYPE,	/* abi::__enum_type_info */
  TK_POINTER_TYPE,	/* abi::__pointer_type_info */
  TK_POINTER_MEMBER_TYPE, /* abi::__pointer_to_member_type_info */
  TK_CLASS_TYPE,	/* abi::__class_type_info */
  TK_SI_CLASS_TYPE,	/* abi::__si_class_type_info */
  TK_FIXED		/* end of fixed descriptors. */
  /* ...		   abi::__vmi_type_info<I> */
} tinfo_kind;

/* Helper macro to get maximum scalar-width of pointer or of the 'long'-type.
   This of interest for llp64 targets.  */
#define LONGPTR_T \
  integer_types[(POINTER_SIZE <= TYPE_PRECISION (integer_types[itk_long]) \
		 ? itk_long : itk_long_long)]

/* A vector of all tinfo decls that haven't yet been emitted.  */
vec<tree, va_gc> *unemitted_tinfo_decls;

/* A vector of all type_info derived types we need.  The first few are
   fixed and created early. The remainder are for multiple inheritance
   and are generated as needed. */
static GTY (()) vec<tinfo_s, va_gc> *tinfo_descs;

static tree ifnonnull (tree, tree, tsubst_flags_t);
static tree tinfo_name (tree, bool);
static tree build_dynamic_cast_1 (tree, tree, tsubst_flags_t);
static tree throw_bad_cast (void);
static tree throw_bad_typeid (void);
static tree get_tinfo_ptr (tree);
static bool typeid_ok_p (void);
static int qualifier_flags (tree);
static bool target_incomplete_p (tree);
static tree tinfo_base_init (tinfo_s *, tree);
static tree generic_initializer (tinfo_s *, tree);
static tree ptr_initializer (tinfo_s *, tree);
static tree ptm_initializer (tinfo_s *, tree);
static tree class_initializer (tinfo_s *, tree, unsigned, ...);
static void create_pseudo_type_info (int, const char *, ...);
static tree get_pseudo_ti_init (tree, unsigned);
static unsigned get_pseudo_ti_index (tree);
static void create_tinfo_types (void);
static bool typeinfo_in_lib_p (tree);

static int doing_runtime = 0;

static void
push_abi_namespace (void)
{
  push_nested_namespace (abi_node);
  push_visibility ("default", 2);
}

static void
pop_abi_namespace (void)
{
  pop_visibility (2);
  pop_nested_namespace (abi_node);
}

/* Declare language defined type_info type and a pointer to const
   type_info.  This is incomplete here, and will be completed when
   the user #includes <typeinfo>.  There are language defined
   restrictions on what can be done until that is included.  Create
   the internal versions of the ABI types.  */

void
init_rtti_processing (void)
{
  tree type_info_type;

  push_namespace (std_identifier);
  type_info_type = xref_tag (class_type, get_identifier ("type_info"),
			     /*tag_scope=*/ts_current, false);
  pop_namespace ();
  const_type_info_type_node
    = cp_build_qualified_type (type_info_type, TYPE_QUAL_CONST);
  type_info_ptr_type = build_pointer_type (const_type_info_type_node);

  vec_alloc (unemitted_tinfo_decls, 124);

  create_tinfo_types ();
}

/* Given the expression EXP of type `class *', return the head of the
   object pointed to by EXP with type cv void*, if the class has any
   virtual functions (TYPE_POLYMORPHIC_P), else just return the
   expression.  */

tree
build_headof (tree exp)
{
  tree type = TREE_TYPE (exp);
  tree offset;
  tree index;

  gcc_assert (TYPE_PTR_P (type));
  type = TREE_TYPE (type);

  if (!TYPE_POLYMORPHIC_P (type))
    return exp;

  /* We use this a couple of times below, protect it.  */
  exp = save_expr (exp);

  /* The offset-to-top field is at index -2 from the vptr.  */
  index = build_int_cst (NULL_TREE,
			 -2 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);

  offset = build_vtbl_ref (cp_build_indirect_ref (exp, RO_NULL, 
                                                  tf_warning_or_error), 
                           index);

  type = cp_build_qualified_type (ptr_type_node,
				  cp_type_quals (TREE_TYPE (exp)));
  return fold_build_pointer_plus (exp, offset);
}

/* Get a bad_cast node for the program to throw...

   See libstdc++/exception.cc for __throw_bad_cast */

static tree
throw_bad_cast (void)
{
  tree fn = get_identifier ("__cxa_bad_cast");
  if (!get_global_value_if_present (fn, &fn))
    fn = push_throw_library_fn (fn, build_function_type_list (ptr_type_node,
							      NULL_TREE));

  return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
}

/* Return an expression for "__cxa_bad_typeid()".  The expression
   returned is an lvalue of type "const std::type_info".  */

static tree
throw_bad_typeid (void)
{
  tree fn = get_identifier ("__cxa_bad_typeid");
  if (!get_global_value_if_present (fn, &fn))
    {
      tree t;

      t = build_reference_type (const_type_info_type_node);
      t = build_function_type_list (t, NULL_TREE);
      fn = push_throw_library_fn (fn, t);
    }

  return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
}

/* Return an lvalue expression whose type is "const std::type_info"
   and whose value indicates the type of the expression EXP.  If EXP
   is a reference to a polymorphic class, return the dynamic type;
   otherwise return the static type of the expression.  */

static tree
get_tinfo_decl_dynamic (tree exp, tsubst_flags_t complain)
{
  tree type;
  tree t;

  if (error_operand_p (exp))
    return error_mark_node;

  exp = resolve_nondeduced_context (exp);

  /* peel back references, so they match.  */
  type = non_reference (TREE_TYPE (exp));

  /* Peel off cv qualifiers.  */
  type = TYPE_MAIN_VARIANT (type);

  /* For UNKNOWN_TYPEs call complete_type_or_else to get diagnostics.  */
  if (CLASS_TYPE_P (type) || type == unknown_type_node
      || type == init_list_type_node)
    type = complete_type_or_maybe_complain (type, exp, complain);

  if (!type)
    return error_mark_node;

  /* If exp is a reference to polymorphic type, get the real type_info.  */
  if (TYPE_POLYMORPHIC_P (type) && ! resolves_to_fixed_type_p (exp, 0))
    {
      /* build reference to type_info from vtable.  */
      tree index;

      /* The RTTI information is at index -1.  */
      index = build_int_cst (NULL_TREE,
			     -1 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
      t = build_vtbl_ref (exp, index);
      t = convert (type_info_ptr_type, t);
    }
  else
    /* Otherwise return the type_info for the static type of the expr.  */
    t = get_tinfo_ptr (TYPE_MAIN_VARIANT (type));

  return cp_build_indirect_ref (t, RO_NULL, complain);
}

static bool
typeid_ok_p (void)
{
  tree pseudo_type_info, type_info_type;

  if (! flag_rtti)
    {
      error ("cannot use typeid with -fno-rtti");
      return false;
    }

  if (!COMPLETE_TYPE_P (const_type_info_type_node))
    {
      error ("must #include <typeinfo> before using typeid");
      return false;
    }

  pseudo_type_info = (*tinfo_descs)[TK_TYPE_INFO_TYPE].type;
  type_info_type = TYPE_MAIN_VARIANT (const_type_info_type_node);

  /* Make sure abi::__type_info_pseudo has the same alias set
     as std::type_info.  */
  if (! TYPE_ALIAS_SET_KNOWN_P (pseudo_type_info))
    TYPE_ALIAS_SET (pseudo_type_info) = get_alias_set (type_info_type);
  else
    gcc_assert (TYPE_ALIAS_SET (pseudo_type_info)
		== get_alias_set (type_info_type));

  return true;
}

/* Return an expression for "typeid(EXP)".  The expression returned is
   an lvalue of type "const std::type_info".  */

tree
build_typeid (tree exp, tsubst_flags_t complain)
{
  tree cond = NULL_TREE, initial_expr = exp;
  int nonnull = 0;

  if (exp == error_mark_node || !typeid_ok_p ())
    return error_mark_node;

  if (processing_template_decl)
    return build_min (TYPEID_EXPR, const_type_info_type_node, exp);

  /* FIXME when integrating with c_fully_fold, mark
     resolves_to_fixed_type_p case as a non-constant expression.  */
  if (TYPE_POLYMORPHIC_P (TREE_TYPE (exp))
      && ! resolves_to_fixed_type_p (exp, &nonnull)
      && ! nonnull)
    {
      /* So we need to look into the vtable of the type of exp.
         Make sure it isn't a null lvalue.  */
      exp = cp_build_addr_expr (exp, complain);
      exp = stabilize_reference (exp);
      cond = cp_convert (boolean_type_node, exp, complain);
      exp = cp_build_indirect_ref (exp, RO_NULL, complain);
    }

  exp = get_tinfo_decl_dynamic (exp, complain);

  if (exp == error_mark_node)
    return error_mark_node;

  if (cond)
    {
      tree bad = throw_bad_typeid ();

      exp = build3 (COND_EXPR, TREE_TYPE (exp), cond, exp, bad);
    }
  else
    mark_type_use (initial_expr);

  return exp;
}

/* Generate the NTBS name of a type.  If MARK_PRIVATE, put a '*' in front so that
   comparisons will be done by pointer rather than string comparison.  */
static tree
tinfo_name (tree type, bool mark_private)
{
  const char *name;
  int length;
  tree name_string;

  name = mangle_type_string (type);
  length = strlen (name);

  if (mark_private)
    {
      /* Inject '*' at beginning of name to force pointer comparison.  */
      char* buf = (char*) XALLOCAVEC (char, length + 2);
      buf[0] = '*';
      memcpy (buf + 1, name, length + 1);
      name_string = build_string (length + 2, buf);
    }
  else
    name_string = build_string (length + 1, name);

  return fix_string_type (name_string);
}

/* Return a VAR_DECL for the internal ABI defined type_info object for
   TYPE. You must arrange that the decl is mark_used, if actually use
   it --- decls in vtables are only used if the vtable is output.  */

tree
get_tinfo_decl (tree type)
{
  tree name;
  tree d;

  if (variably_modified_type_p (type, /*fn=*/NULL_TREE))
    {
      if (array_of_runtime_bound_p (type))
	error ("typeid of array of runtime bound");
      else
	error ("cannot create type information for type %qT because "
	       "it involves types of variable size",
	       type);
      return error_mark_node;
    }

  if (TREE_CODE (type) == METHOD_TYPE)
    type = build_function_type (TREE_TYPE (type),
				TREE_CHAIN (TYPE_ARG_TYPES (type)));

  type = complete_type (type);

  /* For a class type, the variable is cached in the type node
     itself.  */
  if (CLASS_TYPE_P (type))
    {
      d = CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type));
      if (d)
	return d;
    }

  name = mangle_typeinfo_for_type (type);

  d = IDENTIFIER_GLOBAL_VALUE (name);
  if (!d)
    {
      int ix = get_pseudo_ti_index (type);
      tinfo_s *ti = &(*tinfo_descs)[ix];

      d = build_lang_decl (VAR_DECL, name, ti->type);
      SET_DECL_ASSEMBLER_NAME (d, name);
      /* Remember the type it is for.  */
      TREE_TYPE (name) = type;
      DECL_TINFO_P (d) = 1;
      DECL_ARTIFICIAL (d) = 1;
      DECL_IGNORED_P (d) = 1;
      TREE_READONLY (d) = 1;
      TREE_STATIC (d) = 1;
      /* Mark the variable as undefined -- but remember that we can
	 define it later if we need to do so.  */
      DECL_EXTERNAL (d) = 1;
      DECL_NOT_REALLY_EXTERN (d) = 1;
      set_linkage_according_to_type (type, d);

      d = pushdecl_top_level_and_finish (d, NULL_TREE);
      if (CLASS_TYPE_P (type))
	CLASSTYPE_TYPEINFO_VAR (TYPE_MAIN_VARIANT (type)) = d;

      /* Add decl to the global array of tinfo decls.  */
      vec_safe_push (unemitted_tinfo_decls, d);
    }

  return d;
}

/* Return a pointer to a type_info object describing TYPE, suitably
   cast to the language defined type.  */

static tree
get_tinfo_ptr (tree type)
{
  tree decl = get_tinfo_decl (type);

  mark_used (decl);
  return build_nop (type_info_ptr_type,
		    build_address (decl));
}

/* Return the type_info object for TYPE.  */

tree
get_typeid (tree type, tsubst_flags_t complain)
{
  if (type == error_mark_node || !typeid_ok_p ())
    return error_mark_node;

  if (processing_template_decl)
    return build_min (TYPEID_EXPR, const_type_info_type_node, type);

  /* If the type of the type-id is a reference type, the result of the
     typeid expression refers to a type_info object representing the
     referenced type.  */
  type = non_reference (type);

  /* This is not one of the uses of a qualified function type in 8.3.5.  */
  if (TREE_CODE (type) == FUNCTION_TYPE
      && (type_memfn_quals (type) != TYPE_UNQUALIFIED
	  || type_memfn_rqual (type) != REF_QUAL_NONE))
    {
      if (complain & tf_error)
	error ("typeid of qualified function type %qT", type);
      return error_mark_node;
    }

  /* The top-level cv-qualifiers of the lvalue expression or the type-id
     that is the operand of typeid are always ignored.  */
  type = TYPE_MAIN_VARIANT (type);

  /* For UNKNOWN_TYPEs call complete_type_or_else to get diagnostics.  */
  if (CLASS_TYPE_P (type) || type == unknown_type_node
      || type == init_list_type_node)
    type = complete_type_or_maybe_complain (type, NULL_TREE, complain);

  if (!type)
    return error_mark_node;

  return cp_build_indirect_ref (get_tinfo_ptr (type), RO_NULL, complain);
}

/* Check whether TEST is null before returning RESULT.  If TEST is used in
   RESULT, it must have previously had a save_expr applied to it.  */

static tree
ifnonnull (tree test, tree result, tsubst_flags_t complain)
{
  return build3 (COND_EXPR, TREE_TYPE (result),
		 build2 (EQ_EXPR, boolean_type_node, test,
			 cp_convert (TREE_TYPE (test), nullptr_node,
				     complain)),
		 cp_convert (TREE_TYPE (result), nullptr_node, complain),
		 result);
}

/* Execute a dynamic cast, as described in section 5.2.6 of the 9/93 working
   paper.  */

static tree
build_dynamic_cast_1 (tree type, tree expr, tsubst_flags_t complain)
{
  enum tree_code tc = TREE_CODE (type);
  tree exprtype;
  tree dcast_fn;
  tree old_expr = expr;
  const char *errstr = NULL;

  /* Save casted types in the function's used types hash table.  */
  used_types_insert (type);

  /* T shall be a pointer or reference to a complete class type, or
     `pointer to cv void''.  */
  switch (tc)
    {
    case POINTER_TYPE:
      if (VOID_TYPE_P (TREE_TYPE (type)))
	break;
      /* Fall through.  */
    case REFERENCE_TYPE:
      if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (type)))
	{
	  errstr = _("target is not pointer or reference to class");
	  goto fail;
	}
      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (type))))
	{
	  errstr = _("target is not pointer or reference to complete type");
	  goto fail;
	}
      break;

    default:
      errstr = _("target is not pointer or reference");
      goto fail;
    }

  if (tc == POINTER_TYPE)
    {
      expr = decay_conversion (expr, complain);
      exprtype = TREE_TYPE (expr);

      /* If T is a pointer type, v shall be an rvalue of a pointer to
	 complete class type, and the result is an rvalue of type T.  */

      expr = mark_rvalue_use (expr);

      if (!TYPE_PTR_P (exprtype))
	{
	  errstr = _("source is not a pointer");
	  goto fail;
	}
      if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (exprtype)))
	{
	  errstr = _("source is not a pointer to class");
	  goto fail;
	}
      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
	{
	  errstr = _("source is a pointer to incomplete type");
	  goto fail;
	}
    }
  else
    {
      expr = mark_lvalue_use (expr);

      exprtype = build_reference_type (TREE_TYPE (expr));

      /* T is a reference type, v shall be an lvalue of a complete class
	 type, and the result is an lvalue of the type referred to by T.  */

      if (! MAYBE_CLASS_TYPE_P (TREE_TYPE (exprtype)))
	{
	  errstr = _("source is not of class type");
	  goto fail;
	}
      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
	{
	  errstr = _("source is of incomplete class type");
	  goto fail;
	}

      /* Apply trivial conversion T -> T& for dereferenced ptrs.  */
      expr = convert_to_reference (exprtype, expr, CONV_IMPLICIT,
				   LOOKUP_NORMAL, NULL_TREE, complain);
    }

  /* The dynamic_cast operator shall not cast away constness.  */
  if (!at_least_as_qualified_p (TREE_TYPE (type),
				TREE_TYPE (exprtype)))
    {
      errstr = _("conversion casts away constness");
      goto fail;
    }

  /* If *type is an unambiguous accessible base class of *exprtype,
     convert statically.  */
  {
    tree binfo = lookup_base (TREE_TYPE (exprtype), TREE_TYPE (type),
			      ba_check, NULL, complain);
    if (binfo)
      return build_static_cast (type, expr, complain);
  }

  /* Otherwise *exprtype must be a polymorphic class (have a vtbl).  */
  if (TYPE_POLYMORPHIC_P (TREE_TYPE (exprtype)))
    {
      tree expr1;
      /* if TYPE is `void *', return pointer to complete object.  */
      if (tc == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (type)))
	{
	  /* if b is an object, dynamic_cast<void *>(&b) == (void *)&b.  */
	  if (TREE_CODE (expr) == ADDR_EXPR
	      && VAR_P (TREE_OPERAND (expr, 0))
	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == RECORD_TYPE)
	    return build1 (NOP_EXPR, type, expr);

	  /* Since expr is used twice below, save it.  */
	  expr = save_expr (expr);

	  expr1 = build_headof (expr);
	  if (TREE_TYPE (expr1) != type)
	    expr1 = build1 (NOP_EXPR, type, expr1);
	  return ifnonnull (expr, expr1, complain);
	}
      else
	{
	  tree retval;
	  tree result, td2, td3;
	  tree elems[4];
	  tree static_type, target_type, boff;

	  /* If we got here, we can't convert statically.  Therefore,
	     dynamic_cast<D&>(b) (b an object) cannot succeed.  */
	  if (tc == REFERENCE_TYPE)
	    {
	      if (VAR_P (old_expr)
		  && TREE_CODE (TREE_TYPE (old_expr)) == RECORD_TYPE)
		{
		  tree expr = throw_bad_cast ();
                  if (complain & tf_warning)
                    warning (0, "dynamic_cast of %q#D to %q#T can never succeed",
                             old_expr, type);
		  /* Bash it to the expected type.  */
		  TREE_TYPE (expr) = type;
		  return expr;
		}
	    }
	  /* Ditto for dynamic_cast<D*>(&b).  */
	  else if (TREE_CODE (expr) == ADDR_EXPR)
	    {
	      tree op = TREE_OPERAND (expr, 0);
	      if (VAR_P (op)
		  && TREE_CODE (TREE_TYPE (op)) == RECORD_TYPE)
		{
                  if (complain & tf_warning)
                    warning (0, "dynamic_cast of %q#D to %q#T can never succeed",
                             op, type);
		  retval = build_int_cst (type, 0);
		  return retval;
		}
	    }

	  /* Use of dynamic_cast when -fno-rtti is prohibited.  */
	  if (!flag_rtti)
	    {
              if (complain & tf_error)
                error ("%<dynamic_cast%> not permitted with -fno-rtti");
	      return error_mark_node;
	    }

	  target_type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
	  static_type = TYPE_MAIN_VARIANT (TREE_TYPE (exprtype));
	  td2 = get_tinfo_decl (target_type);
	  mark_used (td2);
	  td2 = cp_build_addr_expr (td2, complain);
	  td3 = get_tinfo_decl (static_type);
	  mark_used (td3);
	  td3 = cp_build_addr_expr (td3, complain);

	  /* Determine how T and V are related.  */
	  boff = dcast_base_hint (static_type, target_type);

	  /* Since expr is used twice below, save it.  */
	  expr = save_expr (expr);

	  expr1 = expr;
	  if (tc == REFERENCE_TYPE)
	    expr1 = cp_build_addr_expr (expr1, complain);

	  elems[0] = expr1;
	  elems[1] = td3;
	  elems[2] = td2;
	  elems[3] = boff;

	  dcast_fn = dynamic_cast_node;
	  if (!dcast_fn)
	    {
	      tree tmp;
	      tree tinfo_ptr;
	      const char *name;

	      push_abi_namespace ();
	      tinfo_ptr = xref_tag (class_type,
				    get_identifier ("__class_type_info"),
				    /*tag_scope=*/ts_current, false);

	      tinfo_ptr = build_pointer_type
		(cp_build_qualified_type
		 (tinfo_ptr, TYPE_QUAL_CONST));
	      name = "__dynamic_cast";
	      tmp = build_function_type_list (ptr_type_node,
					      const_ptr_type_node,
					      tinfo_ptr, tinfo_ptr,
					      ptrdiff_type_node, NULL_TREE);
	      dcast_fn = build_library_fn_ptr (name, tmp,
					       ECF_LEAF | ECF_PURE | ECF_NOTHROW);
	      pop_abi_namespace ();
	      dynamic_cast_node = dcast_fn;
	    }
	  result = build_cxx_call (dcast_fn, 4, elems, complain);

	  if (tc == REFERENCE_TYPE)
	    {
	      tree bad = throw_bad_cast ();
	      tree neq;

	      result = save_expr (result);
	      neq = cp_truthvalue_conversion (result);
	      return cp_convert (type,
				 build3 (COND_EXPR, TREE_TYPE (result),
					 neq, result, bad), complain);
	    }

	  /* Now back to the type we want from a void*.  */
	  result = cp_convert (type, result, complain);
	  return ifnonnull (expr, result, complain);
	}
    }
  else
    errstr = _("source type is not polymorphic");

 fail:
  if (complain & tf_error)
    error ("cannot dynamic_cast %qE (of type %q#T) to type %q#T (%s)",
           old_expr, TREE_TYPE (old_expr), type, errstr);
  return error_mark_node;
}

tree
build_dynamic_cast (tree type, tree expr, tsubst_flags_t complain)
{
  tree r;

  if (type == error_mark_node || expr == error_mark_node)
    return error_mark_node;

  if (processing_template_decl)
    {
      expr = build_min (DYNAMIC_CAST_EXPR, type, expr);
      TREE_SIDE_EFFECTS (expr) = 1;
      return convert_from_reference (expr);
    }

  r = convert_from_reference (build_dynamic_cast_1 (type, expr, complain));
  if (r != error_mark_node)
    maybe_warn_about_useless_cast (type, expr, complain);
  return r;
}

/* Return the runtime bit mask encoding the qualifiers of TYPE.  */

static int
qualifier_flags (tree type)
{
  int flags = 0;
  int quals = cp_type_quals (type);

  if (quals & TYPE_QUAL_CONST)
    flags |= 1;
  if (quals & TYPE_QUAL_VOLATILE)
    flags |= 2;
  if (quals & TYPE_QUAL_RESTRICT)
    flags |= 4;
  return flags;
}

/* Return true, if the pointer chain TYPE ends at an incomplete type, or
   contains a pointer to member of an incomplete class.  */

static bool
target_incomplete_p (tree type)
{
  while (true)
    if (TYPE_PTRDATAMEM_P (type))
      {
	if (!COMPLETE_TYPE_P (TYPE_PTRMEM_CLASS_TYPE (type)))
	  return true;
	type = TYPE_PTRMEM_POINTED_TO_TYPE (type);
      }
    else if (TYPE_PTR_P (type))
      type = TREE_TYPE (type);
    else
      return !COMPLETE_OR_VOID_TYPE_P (type);
}

/* Returns true if TYPE involves an incomplete class type; in that
   case, typeinfo variables for TYPE should be emitted with internal
   linkage.  */

static bool
involves_incomplete_p (tree type)
{
  switch (TREE_CODE (type))
    {
    case POINTER_TYPE:
      return target_incomplete_p (TREE_TYPE (type));

    case OFFSET_TYPE:
    ptrmem:
      return
	(target_incomplete_p (TYPE_PTRMEM_POINTED_TO_TYPE (type))
	 || !COMPLETE_TYPE_P (TYPE_PTRMEM_CLASS_TYPE (type)));

    case RECORD_TYPE:
      if (TYPE_PTRMEMFUNC_P (type))
	goto ptrmem;
      /* Fall through.  */
    case UNION_TYPE:
      if (!COMPLETE_TYPE_P (type))
	return true;

    default:
      /* All other types do not involve incomplete class types.  */
      return false;
    }
}

/* Return a CONSTRUCTOR for the common part of the type_info objects. This
   is the vtable pointer and NTBS name.  The NTBS name is emitted as a
   comdat const char array, so it becomes a unique key for the type. Generate
   and emit that VAR_DECL here.  (We can't always emit the type_info itself
   as comdat, because of pointers to incomplete.) */

static tree
tinfo_base_init (tinfo_s *ti, tree target)
{
  tree init;
  tree name_decl;
  tree vtable_ptr;
  vec<constructor_elt, va_gc> *v;

  {
    tree name_name, name_string;

    /* Generate the NTBS array variable.  */
    tree name_type = build_cplus_array_type
		     (cp_build_qualified_type (char_type_node, TYPE_QUAL_CONST),
		     NULL_TREE);

    /* Determine the name of the variable -- and remember with which
       type it is associated.  */
    name_name = mangle_typeinfo_string_for_type (target);
    TREE_TYPE (name_name) = target;

    name_decl = build_lang_decl (VAR_DECL, name_name, name_type);
    SET_DECL_ASSEMBLER_NAME (name_decl, name_name);
    DECL_ARTIFICIAL (name_decl) = 1;
    DECL_IGNORED_P (name_decl) = 1;
    TREE_READONLY (name_decl) = 1;
    TREE_STATIC (name_decl) = 1;
    DECL_EXTERNAL (name_decl) = 0;
    DECL_TINFO_P (name_decl) = 1;
    set_linkage_according_to_type (target, name_decl);
    import_export_decl (name_decl);
    name_string = tinfo_name (target, !TREE_PUBLIC (name_decl));
    DECL_INITIAL (name_decl) = name_string;
    mark_used (name_decl);
    pushdecl_top_level_and_finish (name_decl, name_string);
  }

  vtable_ptr = ti->vtable;
  if (!vtable_ptr)
    {
      tree real_type;
      push_abi_namespace ();
      real_type = xref_tag (class_type, ti->name,
			    /*tag_scope=*/ts_current, false);
      pop_abi_namespace ();

      if (!COMPLETE_TYPE_P (real_type))
	{
	  /* We never saw a definition of this type, so we need to
	     tell the compiler that this is an exported class, as
	     indeed all of the __*_type_info classes are.  */
	  SET_CLASSTYPE_INTERFACE_KNOWN (real_type);
	  CLASSTYPE_INTERFACE_ONLY (real_type) = 1;
	}

      vtable_ptr = get_vtable_decl (real_type, /*complete=*/1);
      vtable_ptr = cp_build_addr_expr (vtable_ptr, tf_warning_or_error);

      /* We need to point into the middle of the vtable.  */
      vtable_ptr = fold_build_pointer_plus
	(vtable_ptr,
	 size_binop (MULT_EXPR,
		     size_int (2 * TARGET_VTABLE_DATA_ENTRY_DISTANCE),
		     TYPE_SIZE_UNIT (vtable_entry_type)));

      ti->vtable = vtable_ptr;
    }

  vec_alloc (v, 2);
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, vtable_ptr);
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
			  decay_conversion (name_decl, tf_warning_or_error));

  init = build_constructor (init_list_type_node, v);
  TREE_CONSTANT (init) = 1;
  TREE_STATIC (init) = 1;

  return init;
}

/* Return the CONSTRUCTOR expr for a type_info of TYPE. TI provides the
   information about the particular type_info derivation, which adds no
   additional fields to the type_info base.  */

static tree
generic_initializer (tinfo_s *ti, tree target)
{
  tree init = tinfo_base_init (ti, target);

  init = build_constructor_single (init_list_type_node, NULL_TREE, init);
  TREE_CONSTANT (init) = 1;
  TREE_STATIC (init) = 1;
  return init;
}

/* Return the CONSTRUCTOR expr for a type_info of pointer TYPE.
   TI provides information about the particular type_info derivation,
   which adds target type and qualifier flags members to the type_info base.  */

static tree
ptr_initializer (tinfo_s *ti, tree target)
{
  tree init = tinfo_base_init (ti, target);
  tree to = TREE_TYPE (target);
  int flags = qualifier_flags (to);
  bool incomplete = target_incomplete_p (to);
  vec<constructor_elt, va_gc> *v;
  vec_alloc (v, 3);

  if (incomplete)
    flags |= 8;
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init);
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, build_int_cst (NULL_TREE, flags));
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                          get_tinfo_ptr (TYPE_MAIN_VARIANT (to)));

  init = build_constructor (init_list_type_node, v);
  TREE_CONSTANT (init) = 1;
  TREE_STATIC (init) = 1;
  return init;
}

/* Return the CONSTRUCTOR expr for a type_info of pointer to member data TYPE.
   TI provides information about the particular type_info derivation,
   which adds class, target type and qualifier flags members to the type_info
   base.  */

static tree
ptm_initializer (tinfo_s *ti, tree target)
{
  tree init = tinfo_base_init (ti, target);
  tree to = TYPE_PTRMEM_POINTED_TO_TYPE (target);
  tree klass = TYPE_PTRMEM_CLASS_TYPE (target);
  int flags = qualifier_flags (to);
  bool incomplete = target_incomplete_p (to);
  vec<constructor_elt, va_gc> *v;
  vec_alloc (v, 4);

  if (incomplete)
    flags |= 0x8;
  if (!COMPLETE_TYPE_P (klass))
    flags |= 0x10;
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init);
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, build_int_cst (NULL_TREE, flags));
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE,
                          get_tinfo_ptr (TYPE_MAIN_VARIANT (to)));
  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, get_tinfo_ptr (klass));

  init = build_constructor (init_list_type_node, v);
  TREE_CONSTANT (init) = 1;
  TREE_STATIC (init) = 1;
  return init;
}

/* Return the CONSTRUCTOR expr for a type_info of class TYPE.
   TI provides information about the particular __class_type_info derivation,
   which adds hint flags and N extra initializers to the type_info base.  */

static tree
class_initializer (tinfo_s *ti, tree target, unsigned n, ...)
{
  tree init = tinfo_base_init (ti, target);
  va_list extra_inits;
  unsigned i;
  vec<constructor_elt, va_gc> *v;
  vec_alloc (v, n+1);

  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init);
  va_start (extra_inits, n);
  for (i = 0; i < n; i++)
    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, va_arg (extra_inits, tree));
  va_end (extra_inits);

  init = build_constructor (init_list_type_node, v);
  TREE_CONSTANT (init) = 1;
  TREE_STATIC (init) = 1;
  return init;
}

/* Returns true if the typeinfo for type should be placed in
   the runtime library.  */

static bool
typeinfo_in_lib_p (tree type)
{
  /* The typeinfo objects for `T*' and `const T*' are in the runtime
     library for simple types T.  */
  if (TYPE_PTR_P (type)
      && (cp_type_quals (TREE_TYPE (type)) == TYPE_QUAL_CONST
	  || cp_type_quals (TREE_TYPE (type)) == TYPE_UNQUALIFIED))
    type = TREE_TYPE (type);

  switch (TREE_CODE (type))
    {
    case INTEGER_TYPE:
    case BOOLEAN_TYPE:
    case REAL_TYPE:
    case VOID_TYPE:
    case NULLPTR_TYPE:
      return true;

    case LANG_TYPE:
      /* fall through.  */

    default:
      return false;
    }
}

/* Generate the initializer for the type info describing TYPE.  TK_INDEX is
   the index of the descriptor in the tinfo_desc vector. */

static tree
get_pseudo_ti_init (tree type, unsigned tk_index)
{
  tinfo_s *ti = &(*tinfo_descs)[tk_index];

  gcc_assert (at_eof);
  switch (tk_index)
    {
    case TK_POINTER_MEMBER_TYPE:
      return ptm_initializer (ti, type);

    case TK_POINTER_TYPE:
      return ptr_initializer (ti, type);

    case TK_BUILTIN_TYPE:
    case TK_ENUMERAL_TYPE:
    case TK_FUNCTION_TYPE:
    case TK_ARRAY_TYPE:
      return generic_initializer (ti, type);

    case TK_CLASS_TYPE:
      return class_initializer (ti, type, 0);

    case TK_SI_CLASS_TYPE:
      {
	tree base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (type), 0);
	tree tinfo = get_tinfo_ptr (BINFO_TYPE (base_binfo));

	/* get_tinfo_ptr might have reallocated the tinfo_descs vector.  */
	ti = &(*tinfo_descs)[tk_index];
	return class_initializer (ti, type, 1, tinfo);
      }

    default:
      {
	int hint = ((CLASSTYPE_REPEATED_BASE_P (type) << 0)
		    | (CLASSTYPE_DIAMOND_SHAPED_P (type) << 1));
	tree binfo = TYPE_BINFO (type);
	int nbases = BINFO_N_BASE_BINFOS (binfo);
	vec<tree, va_gc> *base_accesses = BINFO_BASE_ACCESSES (binfo);
	tree offset_type = LONGPTR_T;
	tree base_inits = NULL_TREE;
	int ix;
	vec<constructor_elt, va_gc> *init_vec = NULL;
	constructor_elt *e;

	gcc_assert (tk_index >= TK_FIXED);

	vec_safe_grow (init_vec, nbases);
	/* Generate the base information initializer.  */
	for (ix = nbases; ix--;)
	  {
	    tree base_binfo = BINFO_BASE_BINFO (binfo, ix);
	    tree base_init;
	    int flags = 0;
	    tree tinfo;
	    tree offset;
	    vec<constructor_elt, va_gc> *v;

	    if ((*base_accesses)[ix] == access_public_node)
	      flags |= 2;
	    tinfo = get_tinfo_ptr (BINFO_TYPE (base_binfo));
	    if (BINFO_VIRTUAL_P (base_binfo))
	      {
		/* We store the vtable offset at which the virtual
		   base offset can be found.  */
		offset = BINFO_VPTR_FIELD (base_binfo);
		flags |= 1;
	      }
	    else
	      offset = BINFO_OFFSET (base_binfo);

	    /* Combine offset and flags into one field.  */
	    offset = fold_convert (offset_type, offset);
	    offset = fold_build2_loc (input_location,
				  LSHIFT_EXPR, offset_type, offset,
				  build_int_cst (offset_type, 8));
	    offset = fold_build2_loc (input_location,
				  BIT_IOR_EXPR, offset_type, offset,
				  build_int_cst (offset_type, flags));
	    vec_alloc (v, 2);
	    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, tinfo);
	    CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, offset);
	    base_init = build_constructor (init_list_type_node, v);
	    e = &(*init_vec)[ix];
	    e->index = NULL_TREE;
	    e->value = base_init;
	  }
	base_inits = build_constructor (init_list_type_node, init_vec);

	/* get_tinfo_ptr might have reallocated the tinfo_descs vector.  */
	ti = &(*tinfo_descs)[tk_index];
	return class_initializer (ti, type, 3,
				  build_int_cst (NULL_TREE, hint),
				  build_int_cst (NULL_TREE, nbases),
				  base_inits);
      }
    }
}

/* Generate the RECORD_TYPE containing the data layout of a type_info
   derivative as used by the runtime. This layout must be consistent with
   that defined in the runtime support. Also generate the VAR_DECL for the
   type's vtable. We explicitly manage the vtable member, and name it for
   real type as used in the runtime. The RECORD type has a different name,
   to avoid collisions.  Return a TREE_LIST who's TINFO_PSEUDO_TYPE
   is the generated type and TINFO_VTABLE_NAME is the name of the
   vtable.  We have to delay generating the VAR_DECL of the vtable
   until the end of the translation, when we'll have seen the library
   definition, if there was one.

   REAL_NAME is the runtime's name of the type. Trailing arguments are
   additional FIELD_DECL's for the structure. The final argument must be
   NULL.  */

static void
create_pseudo_type_info (int tk, const char *real_name, ...)
{
  tinfo_s *ti;
  tree pseudo_type;
  char *pseudo_name;
  tree fields;
  tree field_decl;
  va_list ap;

  va_start (ap, real_name);

  /* Generate the pseudo type name.  */
  pseudo_name = (char *) alloca (strlen (real_name) + 30);
  strcpy (pseudo_name, real_name);
  strcat (pseudo_name, "_pseudo");
  if (tk >= TK_FIXED)
    sprintf (pseudo_name + strlen (pseudo_name), "%d", tk - TK_FIXED);

  /* First field is the pseudo type_info base class.  */
  fields = build_decl (input_location,
		       FIELD_DECL, NULL_TREE,
		       (*tinfo_descs)[TK_TYPE_INFO_TYPE].type);

  /* Now add the derived fields.  */
  while ((field_decl = va_arg (ap, tree)))
    {
      DECL_CHAIN (field_decl) = fields;
      fields = field_decl;
    }

  /* Create the pseudo type.  */
  pseudo_type = make_class_type (RECORD_TYPE);
  finish_builtin_struct (pseudo_type, pseudo_name, fields, NULL_TREE);
  CLASSTYPE_AS_BASE (pseudo_type) = pseudo_type;

  ti = &(*tinfo_descs)[tk];
  ti->type = cp_build_qualified_type (pseudo_type, TYPE_QUAL_CONST);
  ti->name = get_identifier (real_name);
  ti->vtable = NULL_TREE;

  /* Pretend this is public so determine_visibility doesn't give vtables
     internal linkage.  */
  TREE_PUBLIC (TYPE_MAIN_DECL (ti->type)) = 1;

  va_end (ap);
}

/* Return the index of a pseudo type info type node used to describe
   TYPE.  TYPE must be a complete type (or cv void), except at the end
   of the translation unit.  */

static unsigned
get_pseudo_ti_index (tree type)
{
  unsigned ix;

  switch (TREE_CODE (type))
    {
    case OFFSET_TYPE:
      ix = TK_POINTER_MEMBER_TYPE;
      break;

    case POINTER_TYPE:
      ix = TK_POINTER_TYPE;
      break;

    case ENUMERAL_TYPE:
      ix = TK_ENUMERAL_TYPE;
      break;

    case FUNCTION_TYPE:
      ix = TK_FUNCTION_TYPE;
      break;

    case ARRAY_TYPE:
      ix = TK_ARRAY_TYPE;
      break;

    case UNION_TYPE:
    case RECORD_TYPE:
      if (TYPE_PTRMEMFUNC_P (type))
	{
	  ix = TK_POINTER_MEMBER_TYPE;
	  break;
	}
      else if (!COMPLETE_TYPE_P (type))
	{
	  if (!at_eof)
	    cxx_incomplete_type_error (NULL_TREE, type);
	  ix = TK_CLASS_TYPE;
	  break;
	}
      else if (!BINFO_N_BASE_BINFOS (TYPE_BINFO (type)))
	{
	  ix = TK_CLASS_TYPE;
	  break;
	}
      else
	{
	  tree binfo = TYPE_BINFO (type);
	  vec<tree, va_gc> *base_accesses = BINFO_BASE_ACCESSES (binfo);
	  tree base_binfo = BINFO_BASE_BINFO (binfo, 0);
	  int num_bases = BINFO_N_BASE_BINFOS (binfo);

	  if (num_bases == 1
	      && (*base_accesses)[0] == access_public_node
	      && !BINFO_VIRTUAL_P (base_binfo)
	      && integer_zerop (BINFO_OFFSET (base_binfo)))
	    {
	      /* single non-virtual public.  */
	      ix = TK_SI_CLASS_TYPE;
	      break;
	    }
	  else
	    {
	      tinfo_s *ti;
	      tree array_domain, base_array;

	      ix = TK_FIXED + num_bases;
	      if (vec_safe_length (tinfo_descs) <= ix)
		{
		  /* too short, extend.  */
		  unsigned len = vec_safe_length (tinfo_descs);

		  vec_safe_grow (tinfo_descs, ix + 1);
		  while (tinfo_descs->iterate (len++, &ti))
		    ti->type = ti->vtable = ti->name = NULL_TREE;
		}
	      else if ((*tinfo_descs)[ix].type)
		/* already created.  */
		break;

	      /* Create the array of __base_class_type_info entries.
		 G++ 3.2 allocated an array that had one too many
		 entries, and then filled that extra entries with
		 zeros.  */
	      if (abi_version_at_least (2))
		array_domain = build_index_type (size_int (num_bases - 1));
	      else
		array_domain = build_index_type (size_int (num_bases));
	      base_array = build_array_type ((*tinfo_descs)[TK_BASE_TYPE].type,
					     array_domain);

	      push_abi_namespace ();
	      create_pseudo_type_info
		(ix, "__vmi_class_type_info",
		 build_decl (input_location,
			     FIELD_DECL, NULL_TREE, integer_type_node),
		 build_decl (input_location,
			     FIELD_DECL, NULL_TREE, integer_type_node),
		 build_decl (input_location,
			     FIELD_DECL, NULL_TREE, base_array),
		 NULL);
	      pop_abi_namespace ();
	      break;
	    }
	}
    default:
      ix = TK_BUILTIN_TYPE;
      break;
    }
  return ix;
}

/* Make sure the required builtin types exist for generating the type_info
   variable definitions.  */

static void
create_tinfo_types (void)
{
  tinfo_s *ti;

  gcc_assert (!tinfo_descs);

  vec_safe_grow (tinfo_descs, TK_FIXED);

  push_abi_namespace ();

  /* Create the internal type_info structure. This is used as a base for
     the other structures.  */
  {
    tree field, fields;

    field = build_decl (BUILTINS_LOCATION,
			FIELD_DECL, NULL_TREE, const_ptr_type_node);
    fields = field;

    field = build_decl (BUILTINS_LOCATION,
			FIELD_DECL, NULL_TREE, const_string_type_node);
    DECL_CHAIN (field) = fields;
    fields = field;

    ti = &(*tinfo_descs)[TK_TYPE_INFO_TYPE];
    ti->type = make_class_type (RECORD_TYPE);
    ti->vtable = NULL_TREE;
    ti->name = NULL_TREE;
    finish_builtin_struct (ti->type, "__type_info_pseudo",
			   fields, NULL_TREE);
  }

  /* Fundamental type_info */
  create_pseudo_type_info (TK_BUILTIN_TYPE, "__fundamental_type_info", NULL);

  /* Array, function and enum type_info. No additional fields.  */
  create_pseudo_type_info (TK_ARRAY_TYPE, "__array_type_info", NULL);
  create_pseudo_type_info (TK_FUNCTION_TYPE, "__function_type_info", NULL);
  create_pseudo_type_info (TK_ENUMERAL_TYPE, "__enum_type_info", NULL);

  /* Class type_info.  No additional fields.  */
  create_pseudo_type_info (TK_CLASS_TYPE, "__class_type_info", NULL);

  /* Single public non-virtual base class. Add pointer to base class.
     This is really a descendant of __class_type_info.  */
  create_pseudo_type_info (TK_SI_CLASS_TYPE, "__si_class_type_info",
	    build_decl (BUILTINS_LOCATION,
			FIELD_DECL, NULL_TREE, type_info_ptr_type),
	    NULL);

  /* Base class internal helper. Pointer to base type, offset to base,
     flags.  */
  {
    tree field, fields;

    field = build_decl (BUILTINS_LOCATION,
			FIELD_DECL, NULL_TREE, type_info_ptr_type);
    fields = field;

    field = build_decl (BUILTINS_LOCATION,
			FIELD_DECL, NULL_TREE, LONGPTR_T);
    DECL_CHAIN (field) = fields;
    fields = field;

    ti = &(*tinfo_descs)[TK_BASE_TYPE];

    ti->type = make_class_type (RECORD_TYPE);
    ti->vtable = NULL_TREE;
    ti->name = NULL_TREE;
    finish_builtin_struct (ti->type, "__base_class_type_info_pseudo",
			   fields, NULL_TREE);
  }

  /* Pointer type_info. Adds two fields, qualification mask
     and pointer to the pointed to type.  This is really a descendant of
     __pbase_type_info.  */
  create_pseudo_type_info (TK_POINTER_TYPE, "__pointer_type_info",
       build_decl (BUILTINS_LOCATION, 
		   FIELD_DECL, NULL_TREE, integer_type_node),
       build_decl (BUILTINS_LOCATION,
		   FIELD_DECL, NULL_TREE, type_info_ptr_type),
       NULL);

  /* Pointer to member data type_info.  Add qualifications flags,
     pointer to the member's type info and pointer to the class.
     This is really a descendant of __pbase_type_info.  */
  create_pseudo_type_info (TK_POINTER_MEMBER_TYPE,
       "__pointer_to_member_type_info",
	build_decl (BUILTINS_LOCATION,
		    FIELD_DECL, NULL_TREE, integer_type_node),
	build_decl (BUILTINS_LOCATION,
		    FIELD_DECL, NULL_TREE, type_info_ptr_type),
	build_decl (BUILTINS_LOCATION,
		    FIELD_DECL, NULL_TREE, type_info_ptr_type),
	NULL);

  pop_abi_namespace ();
}

/* Emit the type_info descriptors which are guaranteed to be in the runtime
   support.  Generating them here guarantees consistency with the other
   structures.  We use the following heuristic to determine when the runtime
   is being generated.  If std::__fundamental_type_info is defined, and its
   destructor is defined, then the runtime is being built.  */

void
emit_support_tinfos (void)
{
  /* Dummy static variable so we can put nullptr in the array; it will be
     set before we actually start to walk the array.  */
  static tree *const fundamentals[] =
  {
    &void_type_node,
    &boolean_type_node,
    &wchar_type_node, &char16_type_node, &char32_type_node,
    &char_type_node, &signed_char_type_node, &unsigned_char_type_node,
    &short_integer_type_node, &short_unsigned_type_node,
    &integer_type_node, &unsigned_type_node,
    &long_integer_type_node, &long_unsigned_type_node,
    &long_long_integer_type_node, &long_long_unsigned_type_node,
    &int128_integer_type_node, &int128_unsigned_type_node,
    &float_type_node, &double_type_node, &long_double_type_node,
    &dfloat32_type_node, &dfloat64_type_node, &dfloat128_type_node,
    &nullptr_type_node,
    0
  };
  int ix;
  tree bltn_type, dtor;

  push_abi_namespace ();
  bltn_type = xref_tag (class_type,
			get_identifier ("__fundamental_type_info"),
			/*tag_scope=*/ts_current, false);
  pop_abi_namespace ();
  if (!COMPLETE_TYPE_P (bltn_type))
    return;
  dtor = CLASSTYPE_DESTRUCTORS (bltn_type);
  if (!dtor || DECL_EXTERNAL (dtor))
    return;
  doing_runtime = 1;
  for (ix = 0; fundamentals[ix]; ix++)
    {
      tree bltn = *fundamentals[ix];
      tree types[3];
      int i;

      if (bltn == NULL_TREE)
	continue;
      types[0] = bltn;
      types[1] = build_pointer_type (bltn);
      types[2] = build_pointer_type (cp_build_qualified_type (bltn,
							      TYPE_QUAL_CONST));

      for (i = 0; i < 3; ++i)
	{
	  tree tinfo;

	  tinfo = get_tinfo_decl (types[i]);
	  TREE_USED (tinfo) = 1;
	  mark_needed (tinfo);
	  /* The C++ ABI requires that these objects be COMDAT.  But,
	     On systems without weak symbols, initialized COMDAT
	     objects are emitted with internal linkage.  (See
	     comdat_linkage for details.)  Since we want these objects
	     to have external linkage so that copies do not have to be
	     emitted in code outside the runtime library, we make them
	     non-COMDAT here.  

	     It might also not be necessary to follow this detail of the
	     ABI.  */
	  if (!flag_weak || ! targetm.cxx.library_rtti_comdat ())
	    {
	      gcc_assert (TREE_PUBLIC (tinfo) && !DECL_COMDAT (tinfo));
	      DECL_INTERFACE_KNOWN (tinfo) = 1;
	    }
	}
    }
}

/* Finish a type info decl. DECL_PTR is a pointer to an unemitted
   tinfo decl.  Determine whether it needs emitting, and if so
   generate the initializer.  */

bool
emit_tinfo_decl (tree decl)
{
  tree type = TREE_TYPE (DECL_NAME (decl));
  int in_library = typeinfo_in_lib_p (type);

  gcc_assert (DECL_TINFO_P (decl));

  if (in_library)
    {
      if (doing_runtime)
	DECL_EXTERNAL (decl) = 0;
      else
	{
	  /* If we're not in the runtime, then DECL (which is already
	     DECL_EXTERNAL) will not be defined here.  */
	  DECL_INTERFACE_KNOWN (decl) = 1;
	  return false;
	}
    }
  else if (involves_incomplete_p (type))
    {
      if (!decl_needed_p (decl))
	return false;
      /* If TYPE involves an incomplete class type, then the typeinfo
	 object will be emitted with internal linkage.  There is no
	 way to know whether or not types are incomplete until the end
	 of the compilation, so this determination must be deferred
	 until this point.  */
      TREE_PUBLIC (decl) = 0;
      DECL_EXTERNAL (decl) = 0;
      DECL_INTERFACE_KNOWN (decl) = 1;
    }

  import_export_decl (decl);
  if (DECL_NOT_REALLY_EXTERN (decl) && decl_needed_p (decl))
    {
      tree init;

      DECL_EXTERNAL (decl) = 0;
      init = get_pseudo_ti_init (type, get_pseudo_ti_index (type));
      DECL_INITIAL (decl) = init;
      mark_used (decl);
      cp_finish_decl (decl, init, false, NULL_TREE, 0);
      return true;
    }
  else
    return false;
}

#include "gt-cp-rtti.h"