aboutsummaryrefslogtreecommitdiff
path: root/bfd/syms.c
blob: 62acf12f686c979648707fe3e4750907bcd65733 (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
/* Generic symbol-table support for the BFD library.
   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001, 2002, 2003
   Free Software Foundation, Inc.
   Written by Cygnus Support.

   This file is part of BFD, the Binary File Descriptor library.

   This program 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 2 of the License, or
   (at your option) any later version.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/*
SECTION
	Symbols

	BFD tries to maintain as much symbol information as it can when
	it moves information from file to file. BFD passes information
	to applications though the <<asymbol>> structure. When the
	application requests the symbol table, BFD reads the table in
	the native form and translates parts of it into the internal
	format. To maintain more than the information passed to
	applications, some targets keep some information ``behind the
	scenes'' in a structure only the particular back end knows
	about. For example, the coff back end keeps the original
	symbol table structure as well as the canonical structure when
	a BFD is read in. On output, the coff back end can reconstruct
	the output symbol table so that no information is lost, even
	information unique to coff which BFD doesn't know or
	understand. If a coff symbol table were read, but were written
	through an a.out back end, all the coff specific information
	would be lost. The symbol table of a BFD
	is not necessarily read in until a canonicalize request is
	made. Then the BFD back end fills in a table provided by the
	application with pointers to the canonical information.  To
	output symbols, the application provides BFD with a table of
	pointers to pointers to <<asymbol>>s. This allows applications
	like the linker to output a symbol as it was read, since the ``behind
	the scenes'' information will be still available.
@menu
@* Reading Symbols::
@* Writing Symbols::
@* Mini Symbols::
@* typedef asymbol::
@* symbol handling functions::
@end menu

INODE
Reading Symbols, Writing Symbols, Symbols, Symbols
SUBSECTION
	Reading symbols

	There are two stages to reading a symbol table from a BFD:
	allocating storage, and the actual reading process. This is an
	excerpt from an application which reads the symbol table:

|	  long storage_needed;
|	  asymbol **symbol_table;
|	  long number_of_symbols;
|	  long i;
|
|	  storage_needed = bfd_get_symtab_upper_bound (abfd);
|
|         if (storage_needed < 0)
|           FAIL
|
|	  if (storage_needed == 0)
|	    return;
|	  
|	  symbol_table = xmalloc (storage_needed);
|	    ...
|	  number_of_symbols =
|	     bfd_canonicalize_symtab (abfd, symbol_table);
|
|         if (number_of_symbols < 0)
|           FAIL
|
|	  for (i = 0; i < number_of_symbols; i++)
|	    process_symbol (symbol_table[i]);

	All storage for the symbols themselves is in an objalloc
	connected to the BFD; it is freed when the BFD is closed.

INODE
Writing Symbols, Mini Symbols, Reading Symbols, Symbols
SUBSECTION
	Writing symbols

	Writing of a symbol table is automatic when a BFD open for
	writing is closed. The application attaches a vector of
	pointers to pointers to symbols to the BFD being written, and
	fills in the symbol count. The close and cleanup code reads
	through the table provided and performs all the necessary
	operations. The BFD output code must always be provided with an
	``owned'' symbol: one which has come from another BFD, or one
	which has been created using <<bfd_make_empty_symbol>>.  Here is an
	example showing the creation of a symbol table with only one element:

|	#include "bfd.h"
|	int main (void)
|	{
|	  bfd *abfd;
|	  asymbol *ptrs[2];
|	  asymbol *new;
|
|	  abfd = bfd_openw ("foo","a.out-sunos-big");
|	  bfd_set_format (abfd, bfd_object);
|	  new = bfd_make_empty_symbol (abfd);
|	  new->name = "dummy_symbol";
|	  new->section = bfd_make_section_old_way (abfd, ".text");
|	  new->flags = BSF_GLOBAL;
|	  new->value = 0x12345;
|
|	  ptrs[0] = new;
|	  ptrs[1] = 0;
|
|	  bfd_set_symtab (abfd, ptrs, 1);
|	  bfd_close (abfd);
|	  return 0;
|	}
|
|	./makesym
|	nm foo
|	00012345 A dummy_symbol

	Many formats cannot represent arbitary symbol information; for
 	instance, the <<a.out>> object format does not allow an
	arbitary number of sections. A symbol pointing to a section
	which is not one  of <<.text>>, <<.data>> or <<.bss>> cannot
	be described.

INODE
Mini Symbols, typedef asymbol, Writing Symbols, Symbols
SUBSECTION
	Mini Symbols

	Mini symbols provide read-only access to the symbol table.
	They use less memory space, but require more time to access.
	They can be useful for tools like nm or objdump, which may
	have to handle symbol tables of extremely large executables.

	The <<bfd_read_minisymbols>> function will read the symbols
	into memory in an internal form.  It will return a <<void *>>
	pointer to a block of memory, a symbol count, and the size of
	each symbol.  The pointer is allocated using <<malloc>>, and
	should be freed by the caller when it is no longer needed.

	The function <<bfd_minisymbol_to_symbol>> will take a pointer
	to a minisymbol, and a pointer to a structure returned by
	<<bfd_make_empty_symbol>>, and return a <<asymbol>> structure.
	The return value may or may not be the same as the value from
	<<bfd_make_empty_symbol>> which was passed in.

*/

/*
DOCDD
INODE
typedef asymbol, symbol handling functions, Mini Symbols, Symbols

*/
/*
SUBSECTION
	typedef asymbol

	An <<asymbol>> has the form:

*/

/*
CODE_FRAGMENT

.
.typedef struct bfd_symbol
.{
.  {* A pointer to the BFD which owns the symbol. This information
.     is necessary so that a back end can work out what additional
.     information (invisible to the application writer) is carried
.     with the symbol.
.
.     This field is *almost* redundant, since you can use section->owner
.     instead, except that some symbols point to the global sections
.     bfd_{abs,com,und}_section.  This could be fixed by making
.     these globals be per-bfd (or per-target-flavor).  FIXME.  *}
.  struct bfd *the_bfd; {* Use bfd_asymbol_bfd(sym) to access this field.  *}
.
.  {* The text of the symbol. The name is left alone, and not copied; the
.     application may not alter it.  *}
.  const char *name;
.
.  {* The value of the symbol.  This really should be a union of a
.     numeric value with a pointer, since some flags indicate that
.     a pointer to another symbol is stored here.  *}
.  symvalue value;
.
.  {* Attributes of a symbol.  *}
.#define BSF_NO_FLAGS    0x00
.
.  {* The symbol has local scope; <<static>> in <<C>>. The value
.     is the offset into the section of the data.  *}
.#define BSF_LOCAL	0x01
.
.  {* The symbol has global scope; initialized data in <<C>>. The
.     value is the offset into the section of the data.  *}
.#define BSF_GLOBAL	0x02
.
.  {* The symbol has global scope and is exported. The value is
.     the offset into the section of the data.  *}
.#define BSF_EXPORT	BSF_GLOBAL {* No real difference.  *}
.
.  {* A normal C symbol would be one of:
.     <<BSF_LOCAL>>, <<BSF_FORT_COMM>>,  <<BSF_UNDEFINED>> or
.     <<BSF_GLOBAL>>.  *}
.
.  {* The symbol is a debugging record. The value has an arbitary
.     meaning, unless BSF_DEBUGGING_RELOC is also set.  *}
.#define BSF_DEBUGGING	0x08
.
.  {* The symbol denotes a function entry point.  Used in ELF,
.     perhaps others someday.  *}
.#define BSF_FUNCTION    0x10
.
.  {* Used by the linker.  *}
.#define BSF_KEEP        0x20
.#define BSF_KEEP_G      0x40
.
.  {* A weak global symbol, overridable without warnings by
.     a regular global symbol of the same name.  *}
.#define BSF_WEAK        0x80
.
.  {* This symbol was created to point to a section, e.g. ELF's
.     STT_SECTION symbols.  *}
.#define BSF_SECTION_SYM 0x100
.
.  {* The symbol used to be a common symbol, but now it is
.     allocated.  *}
.#define BSF_OLD_COMMON  0x200
.
.  {* The default value for common data.  *}
.#define BFD_FORT_COMM_DEFAULT_VALUE 0
.
.  {* In some files the type of a symbol sometimes alters its
.     location in an output file - ie in coff a <<ISFCN>> symbol
.     which is also <<C_EXT>> symbol appears where it was
.     declared and not at the end of a section.  This bit is set
.     by the target BFD part to convey this information.  *}
.#define BSF_NOT_AT_END    0x400
.
.  {* Signal that the symbol is the label of constructor section.  *}
.#define BSF_CONSTRUCTOR   0x800
.
.  {* Signal that the symbol is a warning symbol.  The name is a
.     warning.  The name of the next symbol is the one to warn about;
.     if a reference is made to a symbol with the same name as the next
.     symbol, a warning is issued by the linker.  *}
.#define BSF_WARNING       0x1000
.
.  {* Signal that the symbol is indirect.  This symbol is an indirect
.     pointer to the symbol with the same name as the next symbol.  *}
.#define BSF_INDIRECT      0x2000
.
.  {* BSF_FILE marks symbols that contain a file name.  This is used
.     for ELF STT_FILE symbols.  *}
.#define BSF_FILE          0x4000
.
.  {* Symbol is from dynamic linking information.  *}
.#define BSF_DYNAMIC	   0x8000
.
.  {* The symbol denotes a data object.  Used in ELF, and perhaps
.     others someday.  *}
.#define BSF_OBJECT	   0x10000
.
.  {* This symbol is a debugging symbol.  The value is the offset
.     into the section of the data.  BSF_DEBUGGING should be set
.     as well.  *}
.#define BSF_DEBUGGING_RELOC 0x20000
.
.  {* This symbol is thread local.  Used in ELF.  *}
.#define BSF_THREAD_LOCAL  0x40000
.
.  flagword flags;
.
.  {* A pointer to the section to which this symbol is
.     relative.  This will always be non NULL, there are special
.     sections for undefined and absolute symbols.  *}
.  struct bfd_section *section;
.
.  {* Back end special data.  *}
.  union
.    {
.      void *p;
.      bfd_vma i;
.    }
.  udata;
.}
.asymbol;
.
*/

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#include "safe-ctype.h"
#include "bfdlink.h"
#include "aout/stab_gnu.h"

/*
DOCDD
INODE
symbol handling functions,  , typedef asymbol, Symbols
SUBSECTION
	Symbol handling functions
*/

/*
FUNCTION
	bfd_get_symtab_upper_bound

DESCRIPTION
	Return the number of bytes required to store a vector of pointers
	to <<asymbols>> for all the symbols in the BFD @var{abfd},
	including a terminal NULL pointer. If there are no symbols in
	the BFD, then return 0.  If an error occurs, return -1.

.#define bfd_get_symtab_upper_bound(abfd) \
.     BFD_SEND (abfd, _bfd_get_symtab_upper_bound, (abfd))
.
*/

/*
FUNCTION
	bfd_is_local_label

SYNOPSIS
        bfd_boolean bfd_is_local_label (bfd *abfd, asymbol *sym);

DESCRIPTION
	Return TRUE if the given symbol @var{sym} in the BFD @var{abfd} is
	a compiler generated local label, else return FALSE.
*/

bfd_boolean
bfd_is_local_label (bfd *abfd, asymbol *sym)
{
  /* The BSF_SECTION_SYM check is needed for IA-64, where every label that
     starts with '.' is local.  This would accidentally catch section names
     if we didn't reject them here.  */
  if ((sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_SECTION_SYM)) != 0)
    return FALSE;
  if (sym->name == NULL)
    return FALSE;
  return bfd_is_local_label_name (abfd, sym->name);
}

/*
FUNCTION
	bfd_is_local_label_name

SYNOPSIS
        bfd_boolean bfd_is_local_label_name (bfd *abfd, const char *name);

DESCRIPTION
	Return TRUE if a symbol with the name @var{name} in the BFD
	@var{abfd} is a compiler generated local label, else return
	FALSE.  This just checks whether the name has the form of a
	local label.

.#define bfd_is_local_label_name(abfd, name) \
.  BFD_SEND (abfd, _bfd_is_local_label_name, (abfd, name))
.
*/

/*
FUNCTION
	bfd_canonicalize_symtab

DESCRIPTION
	Read the symbols from the BFD @var{abfd}, and fills in
	the vector @var{location} with pointers to the symbols and
	a trailing NULL.
	Return the actual number of symbol pointers, not
	including the NULL.

.#define bfd_canonicalize_symtab(abfd, location) \
.  BFD_SEND (abfd, _bfd_canonicalize_symtab, (abfd, location))
.
*/

/*
FUNCTION
	bfd_set_symtab

SYNOPSIS
	bfd_boolean bfd_set_symtab
	  (bfd *abfd, asymbol **location, unsigned int count);

DESCRIPTION
	Arrange that when the output BFD @var{abfd} is closed,
	the table @var{location} of @var{count} pointers to symbols
	will be written.
*/

bfd_boolean
bfd_set_symtab (bfd *abfd, asymbol **location, unsigned int symcount)
{
  if (abfd->format != bfd_object || bfd_read_p (abfd))
    {
      bfd_set_error (bfd_error_invalid_operation);
      return FALSE;
    }

  bfd_get_outsymbols (abfd) = location;
  bfd_get_symcount (abfd) = symcount;
  return TRUE;
}

/*
FUNCTION
	bfd_print_symbol_vandf

SYNOPSIS
	void bfd_print_symbol_vandf (bfd *abfd, void *file, asymbol *symbol);

DESCRIPTION
	Print the value and flags of the @var{symbol} supplied to the
	stream @var{file}.
*/
void
bfd_print_symbol_vandf (bfd *abfd, void *arg, asymbol *symbol)
{
  FILE *file = arg;

  flagword type = symbol->flags;

  if (symbol->section != NULL)
    bfd_fprintf_vma (abfd, file, symbol->value + symbol->section->vma);
  else
    bfd_fprintf_vma (abfd, file, symbol->value);

  /* This presumes that a symbol can not be both BSF_DEBUGGING and
     BSF_DYNAMIC, nor more than one of BSF_FUNCTION, BSF_FILE, and
     BSF_OBJECT.  */
  fprintf (file, " %c%c%c%c%c%c%c",
	   ((type & BSF_LOCAL)
	    ? (type & BSF_GLOBAL) ? '!' : 'l'
	    : (type & BSF_GLOBAL) ? 'g' : ' '),
	   (type & BSF_WEAK) ? 'w' : ' ',
	   (type & BSF_CONSTRUCTOR) ? 'C' : ' ',
	   (type & BSF_WARNING) ? 'W' : ' ',
	   (type & BSF_INDIRECT) ? 'I' : ' ',
	   (type & BSF_DEBUGGING) ? 'd' : (type & BSF_DYNAMIC) ? 'D' : ' ',
	   ((type & BSF_FUNCTION)
	    ? 'F'
	    : ((type & BSF_FILE)
	       ? 'f'
	       : ((type & BSF_OBJECT) ? 'O' : ' '))));
}

/*
FUNCTION
	bfd_make_empty_symbol

DESCRIPTION
	Create a new <<asymbol>> structure for the BFD @var{abfd}
	and return a pointer to it.

	This routine is necessary because each back end has private
	information surrounding the <<asymbol>>. Building your own
	<<asymbol>> and pointing to it will not create the private
	information, and will cause problems later on.

.#define bfd_make_empty_symbol(abfd) \
.  BFD_SEND (abfd, _bfd_make_empty_symbol, (abfd))
.
*/

/*
FUNCTION
	_bfd_generic_make_empty_symbol

SYNOPSIS
	asymbol *_bfd_generic_make_empty_symbol (bfd *);

DESCRIPTION
	Create a new <<asymbol>> structure for the BFD @var{abfd}
	and return a pointer to it.  Used by core file routines,
	binary back-end and anywhere else where no private info
	is needed.
*/

asymbol *
_bfd_generic_make_empty_symbol (bfd *abfd)
{
  bfd_size_type amt = sizeof (asymbol);
  asymbol *new = bfd_zalloc (abfd, amt);
  if (new)
    new->the_bfd = abfd;
  return new;
}

/*
FUNCTION
	bfd_make_debug_symbol

DESCRIPTION
	Create a new <<asymbol>> structure for the BFD @var{abfd},
	to be used as a debugging symbol.  Further details of its use have
	yet to be worked out.

.#define bfd_make_debug_symbol(abfd,ptr,size) \
.  BFD_SEND (abfd, _bfd_make_debug_symbol, (abfd, ptr, size))
.
*/

struct section_to_type
{
  const char *section;
  char type;
};

/* Map section names to POSIX/BSD single-character symbol types.
   This table is probably incomplete.  It is sorted for convenience of
   adding entries.  Since it is so short, a linear search is used.  */
static const struct section_to_type stt[] =
{
  {".bss", 'b'},
  {"code", 't'},		/* MRI .text */
  {".data", 'd'},
  {"*DEBUG*", 'N'},
  {".debug", 'N'},              /* MSVC's .debug (non-standard debug syms) */
  {".drectve", 'i'},            /* MSVC's .drective section */
  {".edata", 'e'},              /* MSVC's .edata (export) section */
  {".fini", 't'},		/* ELF fini section */
  {".idata", 'i'},              /* MSVC's .idata (import) section */
  {".init", 't'},		/* ELF init section */
  {".pdata", 'p'},              /* MSVC's .pdata (stack unwind) section */
  {".rdata", 'r'},		/* Read only data.  */
  {".rodata", 'r'},		/* Read only data.  */
  {".sbss", 's'},		/* Small BSS (uninitialized data).  */
  {".scommon", 'c'},		/* Small common.  */
  {".sdata", 'g'},		/* Small initialized data.  */
  {".text", 't'},
  {"vars", 'd'},		/* MRI .data */
  {"zerovars", 'b'},		/* MRI .bss */
  {0, 0}
};

/* Return the single-character symbol type corresponding to
   section S, or '?' for an unknown COFF section.

   Check for any leading string which matches, so .text5 returns
   't' as well as .text */

static char
coff_section_type (const char *s)
{
  const struct section_to_type *t;

  for (t = &stt[0]; t->section; t++)
    if (!strncmp (s, t->section, strlen (t->section)))
      return t->type;

  return '?';
}

/* Return the single-character symbol type corresponding to section
   SECTION, or '?' for an unknown section.  This uses section flags to
   identify sections.

   FIXME These types are unhandled: c, i, e, p.  If we handled these also,
   we could perhaps obsolete coff_section_type.  */

static char
decode_section_type (const struct bfd_section *section)
{
  if (section->flags & SEC_CODE)
    return 't';
  if (section->flags & SEC_DATA)
    {
      if (section->flags & SEC_READONLY)
	return 'r';
      else if (section->flags & SEC_SMALL_DATA)
	return 'g';
      else
	return 'd';
    }
  if ((section->flags & SEC_HAS_CONTENTS) == 0)
    {
      if (section->flags & SEC_SMALL_DATA)
	return 's';
      else
	return 'b';
    }
  if (section->flags & SEC_DEBUGGING)
    return 'N';
  if ((section->flags & SEC_HAS_CONTENTS) && (section->flags & SEC_READONLY))
    return 'n';

  return '?';
}

/*
FUNCTION
	bfd_decode_symclass

DESCRIPTION
	Return a character corresponding to the symbol
	class of @var{symbol}, or '?' for an unknown class.

SYNOPSIS
	int bfd_decode_symclass (asymbol *symbol);
*/
int
bfd_decode_symclass (asymbol *symbol)
{
  char c;

  if (bfd_is_com_section (symbol->section))
    return 'C';
  if (bfd_is_und_section (symbol->section))
    {
      if (symbol->flags & BSF_WEAK)
	{
	  /* If weak, determine if it's specifically an object
	     or non-object weak.  */
	  if (symbol->flags & BSF_OBJECT)
	    return 'v';
	  else
	    return 'w';
	}
      else
	return 'U';
    }
  if (bfd_is_ind_section (symbol->section))
    return 'I';
  if (symbol->flags & BSF_WEAK)
    {
      /* If weak, determine if it's specifically an object
	 or non-object weak.  */
      if (symbol->flags & BSF_OBJECT)
	return 'V';
      else
	return 'W';
    }
  if (!(symbol->flags & (BSF_GLOBAL | BSF_LOCAL)))
    return '?';

  if (bfd_is_abs_section (symbol->section))
    c = 'a';
  else if (symbol->section)
    {
      c = coff_section_type (symbol->section->name);
      if (c == '?')
	c = decode_section_type (symbol->section);
    }
  else
    return '?';
  if (symbol->flags & BSF_GLOBAL)
    c = TOUPPER (c);
  return c;

  /* We don't have to handle these cases just yet, but we will soon:
     N_SETV: 'v';
     N_SETA: 'l';
     N_SETT: 'x';
     N_SETD: 'z';
     N_SETB: 's';
     N_INDR: 'i';
     */
}

/*
FUNCTION
	bfd_is_undefined_symclass

DESCRIPTION
	Returns non-zero if the class symbol returned by
	bfd_decode_symclass represents an undefined symbol.
	Returns zero otherwise.

SYNOPSIS
	bfd_boolean bfd_is_undefined_symclass (int symclass);
*/

bfd_boolean
bfd_is_undefined_symclass (int symclass)
{
  return symclass == 'U' || symclass == 'w' || symclass == 'v';
}

/*
FUNCTION
	bfd_symbol_info

DESCRIPTION
	Fill in the basic info about symbol that nm needs.
	Additional info may be added by the back-ends after
	calling this function.

SYNOPSIS
	void bfd_symbol_info (asymbol *symbol, symbol_info *ret);
*/

void
bfd_symbol_info (asymbol *symbol, symbol_info *ret)
{
  ret->type = bfd_decode_symclass (symbol);

  if (bfd_is_undefined_symclass (ret->type))
    ret->value = 0;
  else
    ret->value = symbol->value + symbol->section->vma;

  ret->name = symbol->name;
}

/*
FUNCTION
	bfd_copy_private_symbol_data

SYNOPSIS
	bfd_boolean bfd_copy_private_symbol_data
	  (bfd *ibfd, asymbol *isym, bfd *obfd, asymbol *osym);

DESCRIPTION
	Copy private symbol information from @var{isym} in the BFD
	@var{ibfd} to the symbol @var{osym} in the BFD @var{obfd}.
	Return <<TRUE>> on success, <<FALSE>> on error.  Possible error
	returns are:

	o <<bfd_error_no_memory>> -
	Not enough memory exists to create private data for @var{osec}.

.#define bfd_copy_private_symbol_data(ibfd, isymbol, obfd, osymbol) \
.  BFD_SEND (obfd, _bfd_copy_private_symbol_data, \
.            (ibfd, isymbol, obfd, osymbol))
.
*/

/* The generic version of the function which returns mini symbols.
   This is used when the backend does not provide a more efficient
   version.  It just uses BFD asymbol structures as mini symbols.  */

long
_bfd_generic_read_minisymbols (bfd *abfd,
			       bfd_boolean dynamic,
			       void **minisymsp,
			       unsigned int *sizep)
{
  long storage;
  asymbol **syms = NULL;
  long symcount;

  if (dynamic)
    storage = bfd_get_dynamic_symtab_upper_bound (abfd);
  else
    storage = bfd_get_symtab_upper_bound (abfd);
  if (storage < 0)
    goto error_return;
  if (storage == 0)
    return 0;

  syms = bfd_malloc (storage);
  if (syms == NULL)
    goto error_return;

  if (dynamic)
    symcount = bfd_canonicalize_dynamic_symtab (abfd, syms);
  else
    symcount = bfd_canonicalize_symtab (abfd, syms);
  if (symcount < 0)
    goto error_return;

  *minisymsp = syms;
  *sizep = sizeof (asymbol *);
  return symcount;

 error_return:
  bfd_set_error (bfd_error_no_symbols);
  if (syms != NULL)
    free (syms);
  return -1;
}

/* The generic version of the function which converts a minisymbol to
   an asymbol.  We don't worry about the sym argument we are passed;
   we just return the asymbol the minisymbol points to.  */

asymbol *
_bfd_generic_minisymbol_to_symbol (bfd *abfd ATTRIBUTE_UNUSED,
				   bfd_boolean dynamic ATTRIBUTE_UNUSED,
				   const void *minisym,
				   asymbol *sym ATTRIBUTE_UNUSED)
{
  return *(asymbol **) minisym;
}

/* Look through stabs debugging information in .stab and .stabstr
   sections to find the source file and line closest to a desired
   location.  This is used by COFF and ELF targets.  It sets *pfound
   to TRUE if it finds some information.  The *pinfo field is used to
   pass cached information in and out of this routine; this first time
   the routine is called for a BFD, *pinfo should be NULL.  The value
   placed in *pinfo should be saved with the BFD, and passed back each
   time this function is called.  */

/* We use a cache by default.  */

#define ENABLE_CACHING

/* We keep an array of indexentry structures to record where in the
   stabs section we should look to find line number information for a
   particular address.  */

struct indexentry
{
  bfd_vma val;
  bfd_byte *stab;
  bfd_byte *str;
  char *directory_name;
  char *file_name;
  char *function_name;
};

/* Compare two indexentry structures.  This is called via qsort.  */

static int
cmpindexentry (const void *a, const void *b)
{
  const struct indexentry *contestantA = a;
  const struct indexentry *contestantB = b;

  if (contestantA->val < contestantB->val)
    return -1;
  else if (contestantA->val > contestantB->val)
    return 1;
  else
    return 0;
}

/* A pointer to this structure is stored in *pinfo.  */

struct stab_find_info
{
  /* The .stab section.  */
  asection *stabsec;
  /* The .stabstr section.  */
  asection *strsec;
  /* The contents of the .stab section.  */
  bfd_byte *stabs;
  /* The contents of the .stabstr section.  */
  bfd_byte *strs;

  /* A table that indexes stabs by memory address.  */
  struct indexentry *indextable;
  /* The number of entries in indextable.  */
  int indextablesize;

#ifdef ENABLE_CACHING
  /* Cached values to restart quickly.  */
  struct indexentry *cached_indexentry;
  bfd_vma cached_offset;
  bfd_byte *cached_stab;
  char *cached_file_name;
#endif

  /* Saved ptr to malloc'ed filename.  */
  char *filename;
};

bfd_boolean
_bfd_stab_section_find_nearest_line (bfd *abfd,
				     asymbol **symbols,
				     asection *section,
				     bfd_vma offset,
				     bfd_boolean *pfound,
				     const char **pfilename,
				     const char **pfnname,
				     unsigned int *pline,
				     void **pinfo)
{
  struct stab_find_info *info;
  bfd_size_type stabsize, strsize;
  bfd_byte *stab, *str;
  bfd_byte *last_stab = NULL;
  bfd_size_type stroff;
  struct indexentry *indexentry;
  char *file_name;
  char *directory_name;
  int saw_fun;
  bfd_boolean saw_line, saw_func;

  *pfound = FALSE;
  *pfilename = bfd_get_filename (abfd);
  *pfnname = NULL;
  *pline = 0;

  /* Stabs entries use a 12 byte format:
       4 byte string table index
       1 byte stab type
       1 byte stab other field
       2 byte stab desc field
       4 byte stab value
     FIXME: This will have to change for a 64 bit object format.

     The stabs symbols are divided into compilation units.  For the
     first entry in each unit, the type of 0, the value is the length
     of the string table for this unit, and the desc field is the
     number of stabs symbols for this unit.  */

#define STRDXOFF (0)
#define TYPEOFF (4)
#define OTHEROFF (5)
#define DESCOFF (6)
#define VALOFF (8)
#define STABSIZE (12)

  info = *pinfo;
  if (info != NULL)
    {
      if (info->stabsec == NULL || info->strsec == NULL)
	{
	  /* No stabs debugging information.  */
	  return TRUE;
	}

      stabsize = info->stabsec->_raw_size;
      strsize = info->strsec->_raw_size;
    }
  else
    {
      long reloc_size, reloc_count;
      arelent **reloc_vector;
      int i;
      char *name;
      char *function_name;
      bfd_size_type amt = sizeof *info;

      info = bfd_zalloc (abfd, amt);
      if (info == NULL)
	return FALSE;

      /* FIXME: When using the linker --split-by-file or
	 --split-by-reloc options, it is possible for the .stab and
	 .stabstr sections to be split.  We should handle that.  */

      info->stabsec = bfd_get_section_by_name (abfd, ".stab");
      info->strsec = bfd_get_section_by_name (abfd, ".stabstr");

      if (info->stabsec == NULL || info->strsec == NULL)
	{
	  /* No stabs debugging information.  Set *pinfo so that we
             can return quickly in the info != NULL case above.  */
	  *pinfo = info;
	  return TRUE;
	}

      stabsize = info->stabsec->_raw_size;
      strsize = info->strsec->_raw_size;

      info->stabs = bfd_alloc (abfd, stabsize);
      info->strs = bfd_alloc (abfd, strsize);
      if (info->stabs == NULL || info->strs == NULL)
	return FALSE;

      if (! bfd_get_section_contents (abfd, info->stabsec, info->stabs,
				      (bfd_vma) 0, stabsize)
	  || ! bfd_get_section_contents (abfd, info->strsec, info->strs,
					 (bfd_vma) 0, strsize))
	return FALSE;

      /* If this is a relocatable object file, we have to relocate
	 the entries in .stab.  This should always be simple 32 bit
	 relocations against symbols defined in this object file, so
	 this should be no big deal.  */
      reloc_size = bfd_get_reloc_upper_bound (abfd, info->stabsec);
      if (reloc_size < 0)
	return FALSE;
      reloc_vector = bfd_malloc (reloc_size);
      if (reloc_vector == NULL && reloc_size != 0)
	return FALSE;
      reloc_count = bfd_canonicalize_reloc (abfd, info->stabsec, reloc_vector,
					    symbols);
      if (reloc_count < 0)
	{
	  if (reloc_vector != NULL)
	    free (reloc_vector);
	  return FALSE;
	}
      if (reloc_count > 0)
	{
	  arelent **pr;

	  for (pr = reloc_vector; *pr != NULL; pr++)
	    {
	      arelent *r;
	      unsigned long val;
	      asymbol *sym;

	      r = *pr;
	      if (r->howto->rightshift != 0
		  || r->howto->size != 2
		  || r->howto->bitsize != 32
		  || r->howto->pc_relative
		  || r->howto->bitpos != 0
		  || r->howto->dst_mask != 0xffffffff)
		{
		  (*_bfd_error_handler)
		    (_("Unsupported .stab relocation"));
		  bfd_set_error (bfd_error_invalid_operation);
		  if (reloc_vector != NULL)
		    free (reloc_vector);
		  return FALSE;
		}

	      val = bfd_get_32 (abfd, info->stabs + r->address);
	      val &= r->howto->src_mask;
	      sym = *r->sym_ptr_ptr;
	      val += sym->value + sym->section->vma + r->addend;
	      bfd_put_32 (abfd, (bfd_vma) val, info->stabs + r->address);
	    }
	}

      if (reloc_vector != NULL)
	free (reloc_vector);

      /* First time through this function, build a table matching
	 function VM addresses to stabs, then sort based on starting
	 VM address.  Do this in two passes: once to count how many
	 table entries we'll need, and a second to actually build the
	 table.  */

      info->indextablesize = 0;
      saw_fun = 1;
      for (stab = info->stabs; stab < info->stabs + stabsize; stab += STABSIZE)
	{
	  if (stab[TYPEOFF] == (bfd_byte) N_SO)
	    {
	      /* N_SO with null name indicates EOF */
	      if (bfd_get_32 (abfd, stab + STRDXOFF) == 0)
		continue;

	      /* if we did not see a function def, leave space for one.  */
	      if (saw_fun == 0)
		++info->indextablesize;

	      saw_fun = 0;

	      /* two N_SO's in a row is a filename and directory. Skip */
	      if (stab + STABSIZE < info->stabs + stabsize
		  && *(stab + STABSIZE + TYPEOFF) == (bfd_byte) N_SO)
		{
		  stab += STABSIZE;
		}
	    }
	  else if (stab[TYPEOFF] == (bfd_byte) N_FUN)
	    {
	      saw_fun = 1;
	      ++info->indextablesize;
	    }
	}

      if (saw_fun == 0)
	++info->indextablesize;

      if (info->indextablesize == 0)
	return TRUE;
      ++info->indextablesize;

      amt = info->indextablesize;
      amt *= sizeof (struct indexentry);
      info->indextable = bfd_alloc (abfd, amt);
      if (info->indextable == NULL)
	return FALSE;

      file_name = NULL;
      directory_name = NULL;
      saw_fun = 1;

      for (i = 0, stroff = 0, stab = info->stabs, str = info->strs;
	   i < info->indextablesize && stab < info->stabs + stabsize;
	   stab += STABSIZE)
	{
	  switch (stab[TYPEOFF])
	    {
	    case 0:
	      /* This is the first entry in a compilation unit.  */
	      if ((bfd_size_type) ((info->strs + strsize) - str) < stroff)
		break;
	      str += stroff;
	      stroff = bfd_get_32 (abfd, stab + VALOFF);
	      break;

	    case N_SO:
	      /* The main file name.  */

	      /* The following code creates a new indextable entry with
	         a NULL function name if there were no N_FUNs in a file.
	         Note that a N_SO without a file name is an EOF and
	         there could be 2 N_SO following it with the new filename
	         and directory.  */
	      if (saw_fun == 0)
		{
		  info->indextable[i].val = bfd_get_32 (abfd, last_stab + VALOFF);
		  info->indextable[i].stab = last_stab;
		  info->indextable[i].str = str;
		  info->indextable[i].directory_name = directory_name;
		  info->indextable[i].file_name = file_name;
		  info->indextable[i].function_name = NULL;
		  ++i;
		}
	      saw_fun = 0;

	      file_name = (char *) str + bfd_get_32 (abfd, stab + STRDXOFF);
	      if (*file_name == '\0')
		{
		  directory_name = NULL;
		  file_name = NULL;
		  saw_fun = 1;
		}
	      else
		{
		  last_stab = stab;
		  if (stab + STABSIZE >= info->stabs + stabsize
		      || *(stab + STABSIZE + TYPEOFF) != (bfd_byte) N_SO)
		    {
		      directory_name = NULL;
		    }
		  else
		    {
		      /* Two consecutive N_SOs are a directory and a
			 file name.  */
		      stab += STABSIZE;
		      directory_name = file_name;
		      file_name = ((char *) str
				   + bfd_get_32 (abfd, stab + STRDXOFF));
		    }
		}
	      break;

	    case N_SOL:
	      /* The name of an include file.  */
	      file_name = (char *) str + bfd_get_32 (abfd, stab + STRDXOFF);
	      break;

	    case N_FUN:
	      /* A function name.  */
	      saw_fun = 1;
	      name = (char *) str + bfd_get_32 (abfd, stab + STRDXOFF);

	      if (*name == '\0')
		name = NULL;

	      function_name = name;

	      if (name == NULL)
		continue;

	      info->indextable[i].val = bfd_get_32 (abfd, stab + VALOFF);
	      info->indextable[i].stab = stab;
	      info->indextable[i].str = str;
	      info->indextable[i].directory_name = directory_name;
	      info->indextable[i].file_name = file_name;
	      info->indextable[i].function_name = function_name;
	      ++i;
	      break;
	    }
	}

      if (saw_fun == 0)
	{
	  info->indextable[i].val = bfd_get_32 (abfd, last_stab + VALOFF);
	  info->indextable[i].stab = last_stab;
	  info->indextable[i].str = str;
	  info->indextable[i].directory_name = directory_name;
	  info->indextable[i].file_name = file_name;
	  info->indextable[i].function_name = NULL;
	  ++i;
	}

      info->indextable[i].val = (bfd_vma) -1;
      info->indextable[i].stab = info->stabs + stabsize;
      info->indextable[i].str = str;
      info->indextable[i].directory_name = NULL;
      info->indextable[i].file_name = NULL;
      info->indextable[i].function_name = NULL;
      ++i;

      info->indextablesize = i;
      qsort (info->indextable, (size_t) i, sizeof (struct indexentry),
	     cmpindexentry);

      *pinfo = info;
    }

  /* We are passed a section relative offset.  The offsets in the
     stabs information are absolute.  */
  offset += bfd_get_section_vma (abfd, section);

#ifdef ENABLE_CACHING
  if (info->cached_indexentry != NULL
      && offset >= info->cached_offset
      && offset < (info->cached_indexentry + 1)->val)
    {
      stab = info->cached_stab;
      indexentry = info->cached_indexentry;
      file_name = info->cached_file_name;
    }
  else
#endif
    {
      long low, high;
      long mid = -1;

      /* Cache non-existant or invalid.  Do binary search on
         indextable.  */
      indexentry = NULL;

      low = 0;
      high = info->indextablesize - 1;
      while (low != high)
	{
	  mid = (high + low) / 2;
	  if (offset >= info->indextable[mid].val
	      && offset < info->indextable[mid + 1].val)
	    {
	      indexentry = &info->indextable[mid];
	      break;
	    }

	  if (info->indextable[mid].val > offset)
	    high = mid;
	  else
	    low = mid + 1;
	}

      if (indexentry == NULL)
	return TRUE;

      stab = indexentry->stab + STABSIZE;
      file_name = indexentry->file_name;
    }

  directory_name = indexentry->directory_name;
  str = indexentry->str;

  saw_line = FALSE;
  saw_func = FALSE;
  for (; stab < (indexentry+1)->stab; stab += STABSIZE)
    {
      bfd_boolean done;
      bfd_vma val;

      done = FALSE;

      switch (stab[TYPEOFF])
	{
	case N_SOL:
	  /* The name of an include file.  */
	  val = bfd_get_32 (abfd, stab + VALOFF);
	  if (val <= offset)
	    {
	      file_name = (char *) str + bfd_get_32 (abfd, stab + STRDXOFF);
	      *pline = 0;
	    }
	  break;

	case N_SLINE:
	case N_DSLINE:
	case N_BSLINE:
	  /* A line number.  If the function was specified, then the value
	     is relative to the start of the function.  Otherwise, the
	     value is an absolute address.  */
	  val = ((indexentry->function_name ? indexentry->val : 0)
		 + bfd_get_32 (abfd, stab + VALOFF));
	  /* If this line starts before our desired offset, or if it's
	     the first line we've been able to find, use it.  The
	     !saw_line check works around a bug in GCC 2.95.3, which emits
	     the first N_SLINE late.  */
	  if (!saw_line || val <= offset)
	    {
	      *pline = bfd_get_16 (abfd, stab + DESCOFF);

#ifdef ENABLE_CACHING
	      info->cached_stab = stab;
	      info->cached_offset = val;
	      info->cached_file_name = file_name;
	      info->cached_indexentry = indexentry;
#endif
	    }
	  if (val > offset)
	    done = TRUE;
	  saw_line = TRUE;
	  break;

	case N_FUN:
	case N_SO:
	  if (saw_func || saw_line)
	    done = TRUE;
	  saw_func = TRUE;
	  break;
	}

      if (done)
	break;
    }

  *pfound = TRUE;

  if (file_name == NULL || IS_ABSOLUTE_PATH (file_name)
      || directory_name == NULL)
    *pfilename = file_name;
  else
    {
      size_t dirlen;

      dirlen = strlen (directory_name);
      if (info->filename == NULL
	  || strncmp (info->filename, directory_name, dirlen) != 0
	  || strcmp (info->filename + dirlen, file_name) != 0)
	{
	  size_t len;

	  if (info->filename != NULL)
	    free (info->filename);
	  len = strlen (file_name) + 1;
	  info->filename = bfd_malloc (dirlen + len);
	  if (info->filename == NULL)
	    return FALSE;
	  memcpy (info->filename, directory_name, dirlen);
	  memcpy (info->filename + dirlen, file_name, len);
	}

      *pfilename = info->filename;
    }

  if (indexentry->function_name != NULL)
    {
      char *s;

      /* This will typically be something like main:F(0,1), so we want
         to clobber the colon.  It's OK to change the name, since the
         string is in our own local storage anyhow.  */
      s = strchr (indexentry->function_name, ':');
      if (s != NULL)
	*s = '\0';

      *pfnname = indexentry->function_name;
    }

  return TRUE;
}