aboutsummaryrefslogtreecommitdiff
path: root/gas/dwarf2dbg.c
blob: 93b5f480b06a340497aca34d23b16bac70d1b179 (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
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
/* dwarf2dbg.c - DWARF2 debug support
   Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
   Free Software Foundation, Inc.
   Contributed by David Mosberger-Tang <davidm@hpl.hp.com>

   This file is part of GAS, the GNU Assembler.

   GAS 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.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, USA.  */

/* Logical line numbers can be controlled by the compiler via the
   following directives:

	.file FILENO "file.c"
	.loc  FILENO LINENO [COLUMN] [basic_block] [prologue_end] \
	      [epilogue_begin] [is_stmt VALUE] [isa VALUE]
*/

#include "as.h"
#include "safe-ctype.h"

#ifdef HAVE_LIMITS_H
#include <limits.h>
#else
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifndef INT_MAX
#define INT_MAX (int) (((unsigned) (-1)) >> 1)
#endif
#endif

#include "dwarf2dbg.h"
#include <filenames.h>

#ifdef HAVE_DOS_BASED_FILE_SYSTEM
/* We need to decide which character to use as a directory separator.
   Just because HAVE_DOS_BASED_FILE_SYSTEM is defined, it does not
   necessarily mean that the backslash character is the one to use.
   Some environments, eg Cygwin, can support both naming conventions.
   So we use the heuristic that we only need to use the backslash if
   the path is an absolute path starting with a DOS style drive
   selector.  eg C: or D:  */
# define INSERT_DIR_SEPARATOR(string, offset) \
  do \
    { \
      if (offset > 1 \
          && string[0] != 0 \
          && string[1] == ':') \
       string [offset] = '\\'; \
      else \
       string [offset] = '/'; \
    } \
  while (0)
#else
# define INSERT_DIR_SEPARATOR(string, offset) string[offset] = '/'
#endif

#ifndef DWARF2_FORMAT
# define DWARF2_FORMAT() dwarf2_format_32bit
#endif

#ifndef DWARF2_ADDR_SIZE
# define DWARF2_ADDR_SIZE(bfd) (bfd_arch_bits_per_address (bfd) / 8)
#endif

#include "subsegs.h"

#include "elf/dwarf2.h"

/* Since we can't generate the prolog until the body is complete, we
   use three different subsegments for .debug_line: one holding the
   prolog, one for the directory and filename info, and one for the
   body ("statement program").  */
#define DL_PROLOG	0
#define DL_FILES	1
#define DL_BODY		2

/* If linker relaxation might change offsets in the code, the DWARF special
   opcodes and variable-length operands cannot be used.  If this macro is
   nonzero, use the DW_LNS_fixed_advance_pc opcode instead.  */
#ifndef DWARF2_USE_FIXED_ADVANCE_PC
# define DWARF2_USE_FIXED_ADVANCE_PC	0
#endif

/* First special line opcde - leave room for the standard opcodes.
   Note: If you want to change this, you'll have to update the
   "standard_opcode_lengths" table that is emitted below in
   out_debug_line().  */
#define DWARF2_LINE_OPCODE_BASE		13

#ifndef DWARF2_LINE_BASE
  /* Minimum line offset in a special line info. opcode.  This value
     was chosen to give a reasonable range of values.  */
# define DWARF2_LINE_BASE		-5
#endif

/* Range of line offsets in a special line info. opcode.  */
#ifndef DWARF2_LINE_RANGE
# define DWARF2_LINE_RANGE		14
#endif

#ifndef DWARF2_LINE_MIN_INSN_LENGTH
  /* Define the architecture-dependent minimum instruction length (in
     bytes).  This value should be rather too small than too big.  */
# define DWARF2_LINE_MIN_INSN_LENGTH	1
#endif

/* Flag that indicates the initial value of the is_stmt_start flag.  */
#define	DWARF2_LINE_DEFAULT_IS_STMT	1

/* Given a special op, return the line skip amount.  */
#define SPECIAL_LINE(op) \
	(((op) - DWARF2_LINE_OPCODE_BASE)%DWARF2_LINE_RANGE + DWARF2_LINE_BASE)

/* Given a special op, return the address skip amount (in units of
   DWARF2_LINE_MIN_INSN_LENGTH.  */
#define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)

/* The maximum address skip amount that can be encoded with a special op.  */
#define MAX_SPECIAL_ADDR_DELTA		SPECIAL_ADDR(255)

struct line_entry {
  struct line_entry *next;
  symbolS *label;
  struct dwarf2_line_info loc;
};

struct line_subseg {
  struct line_subseg *next;
  subsegT subseg;
  struct line_entry *head;
  struct line_entry **ptail;
};

struct line_seg {
  struct line_seg *next;
  segT seg;
  struct line_subseg *head;
  symbolS *text_start;
  symbolS *text_end;
};

/* Collects data for all line table entries during assembly.  */
static struct line_seg *all_segs;

struct file_entry {
  const char *filename;
  unsigned int dir;
};

/* Table of files used by .debug_line.  */
static struct file_entry *files;
static unsigned int files_in_use;
static unsigned int files_allocated;

/* Table of directories used by .debug_line.  */
static char **dirs;
static unsigned int dirs_in_use;
static unsigned int dirs_allocated;

/* TRUE when we've seen a .loc directive recently.  Used to avoid
   doing work when there's nothing to do.  */
static bfd_boolean loc_directive_seen;

/* TRUE when we're supposed to set the basic block mark whenever a
   label is seen.  */
bfd_boolean dwarf2_loc_mark_labels;

/* Current location as indicated by the most recent .loc directive.  */
static struct dwarf2_line_info current = {
  1, 1, 0, 0,
  DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0
};

/* The size of an address on the target.  */
static unsigned int sizeof_address;

static struct line_subseg *get_line_subseg (segT, subsegT);
static unsigned int get_filenum (const char *, unsigned int);
static struct frag *first_frag_for_seg (segT);
static struct frag *last_frag_for_seg (segT);
static void out_byte (int);
static void out_opcode (int);
static void out_two (int);
static void out_four (int);
static void out_abbrev (int, int);
static void out_uleb128 (addressT);
static void out_sleb128 (addressT);
static offsetT get_frag_fix (fragS *, segT);
static void out_set_addr (symbolS *);
static int size_inc_line_addr (int, addressT);
static void emit_inc_line_addr (int, addressT, char *, int);
static void out_inc_line_addr (int, addressT);
static void out_fixed_inc_line_addr (int, symbolS *, symbolS *);
static void relax_inc_line_addr (int, symbolS *, symbolS *);
static void process_entries (segT, struct line_entry *);
static void out_file_list (void);
static void out_debug_line (segT);
static void out_debug_aranges (segT, segT);
static void out_debug_abbrev (segT);

#ifndef TC_DWARF2_EMIT_OFFSET
#define TC_DWARF2_EMIT_OFFSET  generic_dwarf2_emit_offset

/* Create an offset to .dwarf2_*.  */

static void
generic_dwarf2_emit_offset (symbolS *symbol, unsigned int size)
{
  expressionS expr;

  expr.X_op = O_symbol;
  expr.X_add_symbol = symbol;
  expr.X_add_number = 0;
  emit_expr (&expr, size);
}
#endif

/* Find or create an entry for SEG+SUBSEG in ALL_SEGS.  */

static struct line_subseg *
get_line_subseg (segT seg, subsegT subseg)
{
  static segT last_seg;
  static subsegT last_subseg;
  static struct line_subseg *last_line_subseg;

  struct line_seg **ps, *s;
  struct line_subseg **pss, *ss;

  if (seg == last_seg && subseg == last_subseg)
    return last_line_subseg;

  for (ps = &all_segs; (s = *ps) != NULL; ps = &s->next)
    if (s->seg == seg)
      goto found_seg;

  s = (struct line_seg *) xmalloc (sizeof (*s));
  s->next = NULL;
  s->seg = seg;
  s->head = NULL;
  *ps = s;

 found_seg:
  for (pss = &s->head; (ss = *pss) != NULL ; pss = &ss->next)
    {
      if (ss->subseg == subseg)
	goto found_subseg;
      if (ss->subseg > subseg)
	break;
    }

  ss = (struct line_subseg *) xmalloc (sizeof (*ss));
  ss->next = *pss;
  ss->subseg = subseg;
  ss->head = NULL;
  ss->ptail = &ss->head;
  *pss = ss;

 found_subseg:
  last_seg = seg;
  last_subseg = subseg;
  last_line_subseg = ss;

  return ss;
}

/* Record an entry for LOC occurring at LABEL.  */

static void
dwarf2_gen_line_info_1 (symbolS *label, struct dwarf2_line_info *loc)
{
  struct line_subseg *ss;
  struct line_entry *e;

  e = (struct line_entry *) xmalloc (sizeof (*e));
  e->next = NULL;
  e->label = label;
  e->loc = *loc;

  ss = get_line_subseg (now_seg, now_subseg);
  *ss->ptail = e;
  ss->ptail = &e->next;
}

/* Record an entry for LOC occurring at OFS within the current fragment.  */

void
dwarf2_gen_line_info (addressT ofs, struct dwarf2_line_info *loc)
{
  static unsigned int line = -1;
  static unsigned int filenum = -1;

  symbolS *sym;

  /* Early out for as-yet incomplete location information.  */
  if (loc->filenum == 0 || loc->line == 0)
    return;

  /* Don't emit sequences of line symbols for the same line when the
     symbols apply to assembler code.  It is necessary to emit
     duplicate line symbols when a compiler asks for them, because GDB
     uses them to determine the end of the prologue.  */
  if (debug_type == DEBUG_DWARF2
      && line == loc->line && filenum == loc->filenum)
    return;

  line = loc->line;
  filenum = loc->filenum;

  sym = symbol_temp_new (now_seg, ofs, frag_now);
  dwarf2_gen_line_info_1 (sym, loc);
}

/* Returns the current source information.  If .file directives have
   been encountered, the info for the corresponding source file is
   returned.  Otherwise, the info for the assembly source file is
   returned.  */

void
dwarf2_where (struct dwarf2_line_info *line)
{
  if (debug_type == DEBUG_DWARF2)
    {
      char *filename;
      as_where (&filename, &line->line);
      line->filenum = get_filenum (filename, 0);
      line->column = 0;
      line->flags = DWARF2_FLAG_IS_STMT;
      line->isa = current.isa;
    }
  else
    *line = current;
}

/* A hook to allow the target backend to inform the line number state 
   machine of isa changes when assembler debug info is enabled.  */

void
dwarf2_set_isa (unsigned int isa)
{
  current.isa = isa;
}

/* Called for each machine instruction, or relatively atomic group of
   machine instructions (ie built-in macro).  The instruction or group
   is SIZE bytes in length.  If dwarf2 line number generation is called
   for, emit a line statement appropriately.  */

void
dwarf2_emit_insn (int size)
{
  struct dwarf2_line_info loc;

  if (loc_directive_seen)
    {
      /* Use the last location established by a .loc directive, not
	 the value returned by dwarf2_where().  That calls as_where()
	 which will return either the logical input file name (foo.c)
	or the physical input file name (foo.s) and not the file name
	specified in the most recent .loc directive (eg foo.h).  */
      loc = current;

      /* Unless we generate DWARF2 debugging information for each
	 assembler line, we only emit one line symbol for one LOC.  */
      if (debug_type != DEBUG_DWARF2)
	loc_directive_seen = FALSE;
    }
  else if (debug_type != DEBUG_DWARF2)
    return;
  else
    dwarf2_where (&loc);

  dwarf2_gen_line_info (frag_now_fix () - size, &loc);

  current.flags &= ~(DWARF2_FLAG_BASIC_BLOCK
		     | DWARF2_FLAG_PROLOGUE_END
		     | DWARF2_FLAG_EPILOGUE_BEGIN);
}

/* Called for each (preferably code) label.  If dwarf2_loc_mark_labels
   is enabled, emit a basic block marker.  */

void
dwarf2_emit_label (symbolS *label)
{
  struct dwarf2_line_info loc;

  if (!dwarf2_loc_mark_labels)
    return;
  if (S_GET_SEGMENT (label) != now_seg)
    return;
  if (!(bfd_get_section_flags (stdoutput, now_seg) & SEC_CODE))
    return;
  
  if (debug_type == DEBUG_DWARF2)
    dwarf2_where (&loc);
  else
    {
      loc = current;
      loc_directive_seen = FALSE;
    }

  loc.flags |= DWARF2_FLAG_BASIC_BLOCK;

  current.flags &= ~(DWARF2_FLAG_BASIC_BLOCK
		     | DWARF2_FLAG_PROLOGUE_END
		     | DWARF2_FLAG_EPILOGUE_BEGIN);

  dwarf2_gen_line_info_1 (label, &loc);
}

/* Get a .debug_line file number for FILENAME.  If NUM is nonzero,
   allocate it on that file table slot, otherwise return the first
   empty one.  */

static unsigned int
get_filenum (const char *filename, unsigned int num)
{
  static unsigned int last_used, last_used_dir_len;
  const char *file;
  size_t dir_len;
  unsigned int i, dir;

  if (num == 0 && last_used)
    {
      if (! files[last_used].dir
	  && strcmp (filename, files[last_used].filename) == 0)
	return last_used;
      if (files[last_used].dir
	  && strncmp (filename, dirs[files[last_used].dir],
		      last_used_dir_len) == 0
	  && IS_DIR_SEPARATOR (filename [last_used_dir_len])
	  && strcmp (filename + last_used_dir_len + 1,
		     files[last_used].filename) == 0)
	return last_used;
    }

  file = lbasename (filename);
  /* Don't make empty string from / or A: from A:/ .  */
#ifdef HAVE_DOS_BASED_FILE_SYSTEM
  if (file <= filename + 3)
    file = filename;
#else
  if (file == filename + 1)
    file = filename;
#endif
  dir_len = file - filename;

  dir = 0;
  if (dir_len)
    {
      --dir_len;
      for (dir = 1; dir < dirs_in_use; ++dir)
	if (strncmp (filename, dirs[dir], dir_len) == 0
	    && dirs[dir][dir_len] == '\0')
	  break;

      if (dir >= dirs_in_use)
	{
	  if (dir >= dirs_allocated)
	    {
	      dirs_allocated = dir + 32;
	      dirs = (char **)
		     xrealloc (dirs, (dir + 32) * sizeof (const char *));
	    }

	  dirs[dir] = xmalloc (dir_len + 1);
	  memcpy (dirs[dir], filename, dir_len);
	  dirs[dir][dir_len] = '\0';
	  dirs_in_use = dir + 1;
	}
    }

  if (num == 0)
    {
      for (i = 1; i < files_in_use; ++i)
	if (files[i].dir == dir
	    && files[i].filename
	    && strcmp (file, files[i].filename) == 0)
	  {
	    last_used = i;
	    last_used_dir_len = dir_len;
	    return i;
	  }
    }
  else
    i = num;

  if (i >= files_allocated)
    {
      unsigned int old = files_allocated;

      files_allocated = i + 32;
      files = (struct file_entry *)
	xrealloc (files, (i + 32) * sizeof (struct file_entry));

      memset (files + old, 0, (i + 32 - old) * sizeof (struct file_entry));
    }

  files[i].filename = num ? file : xstrdup (file);
  files[i].dir = dir;
  if (files_in_use < i + 1)
    files_in_use = i + 1;
  last_used = i;
  last_used_dir_len = dir_len;

  return i;
}

/* Handle two forms of .file directive:
   - Pass .file "source.c" to s_app_file
   - Handle .file 1 "source.c" by adding an entry to the DWARF-2 file table

   If an entry is added to the file table, return a pointer to the filename. */

char *
dwarf2_directive_file (int dummy ATTRIBUTE_UNUSED)
{
  offsetT num;
  char *filename;
  int filename_len;

  /* Continue to accept a bare string and pass it off.  */
  SKIP_WHITESPACE ();
  if (*input_line_pointer == '"')
    {
      s_app_file (0);
      return NULL;
    }

  num = get_absolute_expression ();
  filename = demand_copy_C_string (&filename_len);
  if (filename == NULL)
    return NULL;
  demand_empty_rest_of_line ();

  if (num < 1)
    {
      as_bad (_("file number less than one"));
      return NULL;
    }

  if (num < (int) files_in_use && files[num].filename != 0)
    {
      as_bad (_("file number %ld already allocated"), (long) num);
      return NULL;
    }

  get_filenum (filename, num);

  return filename;
}

void
dwarf2_directive_loc (int dummy ATTRIBUTE_UNUSED)
{
  offsetT filenum, line;

  filenum = get_absolute_expression ();
  SKIP_WHITESPACE ();
  line = get_absolute_expression ();

  if (filenum < 1)
    {
      as_bad (_("file number less than one"));
      return;
    }
  if (filenum >= (int) files_in_use || files[filenum].filename == 0)
    {
      as_bad (_("unassigned file number %ld"), (long) filenum);
      return;
    }

  current.filenum = filenum;
  current.line = line;

#ifndef NO_LISTING
  if (listing)
    {
      if (files[filenum].dir)
	{
	  size_t dir_len = strlen (dirs[files[filenum].dir]);
	  size_t file_len = strlen (files[filenum].filename);
	  char *cp = (char *) alloca (dir_len + 1 + file_len + 1);

	  memcpy (cp, dirs[files[filenum].dir], dir_len);
	  INSERT_DIR_SEPARATOR (cp, dir_len);
	  memcpy (cp + dir_len + 1, files[filenum].filename, file_len);
	  cp[dir_len + file_len + 1] = '\0';
	  listing_source_file (cp);
	}
      else
	listing_source_file (files[filenum].filename);
      listing_source_line (line);
    }
#endif

  SKIP_WHITESPACE ();
  if (ISDIGIT (*input_line_pointer))
    {
      current.column = get_absolute_expression ();
      SKIP_WHITESPACE ();
    }

  while (ISALPHA (*input_line_pointer))
    {
      char *p, c;
      offsetT value;

      p = input_line_pointer;
      c = get_symbol_end ();

      if (strcmp (p, "basic_block") == 0)
	{
	  current.flags |= DWARF2_FLAG_BASIC_BLOCK;
	  *input_line_pointer = c;
	}
      else if (strcmp (p, "prologue_end") == 0)
	{
	  current.flags |= DWARF2_FLAG_PROLOGUE_END;
	  *input_line_pointer = c;
	}
      else if (strcmp (p, "epilogue_begin") == 0)
	{
	  current.flags |= DWARF2_FLAG_EPILOGUE_BEGIN;
	  *input_line_pointer = c;
	}
      else if (strcmp (p, "is_stmt") == 0)
	{
	  *input_line_pointer = c;
	  value = get_absolute_expression ();
	  if (value == 0)
	    current.flags &= ~DWARF2_FLAG_IS_STMT;
	  else if (value == 1)
	    current.flags |= DWARF2_FLAG_IS_STMT;
	  else
	    {
	      as_bad (_("is_stmt value not 0 or 1"));
	      return;
	    }
	}
      else if (strcmp (p, "isa") == 0)
	{
          *input_line_pointer = c;
	  value = get_absolute_expression ();
	  if (value >= 0)
	    current.isa = value;
	  else
	    {
	      as_bad (_("isa number less than zero"));
	      return;
	    }
	}
      else
	{
	  as_bad (_("unknown .loc sub-directive `%s'"), p);
          *input_line_pointer = c;
	  return;
	}

      SKIP_WHITESPACE ();
    }

  demand_empty_rest_of_line ();
  loc_directive_seen = TRUE;
}

void
dwarf2_directive_loc_mark_labels (int dummy ATTRIBUTE_UNUSED)
{
  offsetT value = get_absolute_expression ();

  if (value != 0 && value != 1)
    {
      as_bad (_("expected 0 or 1"));
      ignore_rest_of_line ();
    }
  else
    {
      dwarf2_loc_mark_labels = value != 0;
      demand_empty_rest_of_line ();
    }
}

static struct frag *
first_frag_for_seg (segT seg)
{
  return seg_info (seg)->frchainP->frch_root;
}

static struct frag *
last_frag_for_seg (segT seg)
{
  frchainS *f = seg_info (seg)->frchainP;

  while (f->frch_next != NULL)
    f = f->frch_next;

  return f->frch_last;
}

/* Emit a single byte into the current segment.  */

static inline void
out_byte (int byte)
{
  FRAG_APPEND_1_CHAR (byte);
}

/* Emit a statement program opcode into the current segment.  */

static inline void
out_opcode (int opc)
{
  out_byte (opc);
}

/* Emit a two-byte word into the current segment.  */

static inline void
out_two (int data)
{
  md_number_to_chars (frag_more (2), data, 2);
}

/* Emit a four byte word into the current segment.  */

static inline void
out_four (int data)
{
  md_number_to_chars (frag_more (4), data, 4);
}

/* Emit an unsigned "little-endian base 128" number.  */

static void
out_uleb128 (addressT value)
{
  output_leb128 (frag_more (sizeof_leb128 (value, 0)), value, 0);
}

/* Emit a signed "little-endian base 128" number.  */

static void
out_sleb128 (addressT value)
{
  output_leb128 (frag_more (sizeof_leb128 (value, 1)), value, 1);
}

/* Emit a tuple for .debug_abbrev.  */

static inline void
out_abbrev (int name, int form)
{
  out_uleb128 (name);
  out_uleb128 (form);
}

/* Get the size of a fragment.  */

static offsetT
get_frag_fix (fragS *frag, segT seg)
{
  frchainS *fr;

  if (frag->fr_next)
    return frag->fr_fix;

  /* If a fragment is the last in the chain, special measures must be
     taken to find its size before relaxation, since it may be pending
     on some subsegment chain.  */
  for (fr = seg_info (seg)->frchainP; fr; fr = fr->frch_next)
    if (fr->frch_last == frag)
      return (char *) obstack_next_free (&fr->frch_obstack) - frag->fr_literal;

  abort ();
}

/* Set an absolute address (may result in a relocation entry).  */

static void
out_set_addr (symbolS *sym)
{
  expressionS expr;

  out_opcode (DW_LNS_extended_op);
  out_uleb128 (sizeof_address + 1);

  out_opcode (DW_LNE_set_address);
  expr.X_op = O_symbol;
  expr.X_add_symbol = sym;
  expr.X_add_number = 0;
  emit_expr (&expr, sizeof_address);
}

#if DWARF2_LINE_MIN_INSN_LENGTH > 1
static void scale_addr_delta (addressT *);

static void
scale_addr_delta (addressT *addr_delta)
{
  static int printed_this = 0;
  if (*addr_delta % DWARF2_LINE_MIN_INSN_LENGTH != 0)
    {
      if (!printed_this)
	as_bad("unaligned opcodes detected in executable segment");
      printed_this = 1;
    }
  *addr_delta /= DWARF2_LINE_MIN_INSN_LENGTH;
}
#else
#define scale_addr_delta(A)
#endif

/* Encode a pair of line and address skips as efficiently as possible.
   Note that the line skip is signed, whereas the address skip is unsigned.

   The following two routines *must* be kept in sync.  This is
   enforced by making emit_inc_line_addr abort if we do not emit
   exactly the expected number of bytes.  */

static int
size_inc_line_addr (int line_delta, addressT addr_delta)
{
  unsigned int tmp, opcode;
  int len = 0;

  /* Scale the address delta by the minimum instruction length.  */
  scale_addr_delta (&addr_delta);

  /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence.
     We cannot use special opcodes here, since we want the end_sequence
     to emit the matrix entry.  */
  if (line_delta == INT_MAX)
    {
      if (addr_delta == MAX_SPECIAL_ADDR_DELTA)
	len = 1;
      else
	len = 1 + sizeof_leb128 (addr_delta, 0);
      return len + 3;
    }

  /* Bias the line delta by the base.  */
  tmp = line_delta - DWARF2_LINE_BASE;

  /* If the line increment is out of range of a special opcode, we
     must encode it with DW_LNS_advance_line.  */
  if (tmp >= DWARF2_LINE_RANGE)
    {
      len = 1 + sizeof_leb128 (line_delta, 1);
      line_delta = 0;
      tmp = 0 - DWARF2_LINE_BASE;
    }

  /* Bias the opcode by the special opcode base.  */
  tmp += DWARF2_LINE_OPCODE_BASE;

  /* Avoid overflow when addr_delta is large.  */
  if (addr_delta < 256 + MAX_SPECIAL_ADDR_DELTA)
    {
      /* Try using a special opcode.  */
      opcode = tmp + addr_delta * DWARF2_LINE_RANGE;
      if (opcode <= 255)
	return len + 1;

      /* Try using DW_LNS_const_add_pc followed by special op.  */
      opcode = tmp + (addr_delta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
      if (opcode <= 255)
	return len + 2;
    }

  /* Otherwise use DW_LNS_advance_pc.  */
  len += 1 + sizeof_leb128 (addr_delta, 0);

  /* DW_LNS_copy or special opcode.  */
  len += 1;

  return len;
}

static void
emit_inc_line_addr (int line_delta, addressT addr_delta, char *p, int len)
{
  unsigned int tmp, opcode;
  int need_copy = 0;
  char *end = p + len;

  /* Line number sequences cannot go backward in addresses.  This means
     we've incorrectly ordered the statements in the sequence.  */
  assert ((offsetT) addr_delta >= 0);

  /* Scale the address delta by the minimum instruction length.  */
  scale_addr_delta (&addr_delta);

  /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence.
     We cannot use special opcodes here, since we want the end_sequence
     to emit the matrix entry.  */
  if (line_delta == INT_MAX)
    {
      if (addr_delta == MAX_SPECIAL_ADDR_DELTA)
	*p++ = DW_LNS_const_add_pc;
      else
	{
	  *p++ = DW_LNS_advance_pc;
	  p += output_leb128 (p, addr_delta, 0);
	}

      *p++ = DW_LNS_extended_op;
      *p++ = 1;
      *p++ = DW_LNE_end_sequence;
      goto done;
    }

  /* Bias the line delta by the base.  */
  tmp = line_delta - DWARF2_LINE_BASE;

  /* If the line increment is out of range of a special opcode, we
     must encode it with DW_LNS_advance_line.  */
  if (tmp >= DWARF2_LINE_RANGE)
    {
      *p++ = DW_LNS_advance_line;
      p += output_leb128 (p, line_delta, 1);

      line_delta = 0;
      tmp = 0 - DWARF2_LINE_BASE;
      need_copy = 1;
    }

  /* Prettier, I think, to use DW_LNS_copy instead of a "line +0, addr +0"
     special opcode.  */
  if (line_delta == 0 && addr_delta == 0)
    {
      *p++ = DW_LNS_copy;
      goto done;
    }

  /* Bias the opcode by the special opcode base.  */
  tmp += DWARF2_LINE_OPCODE_BASE;

  /* Avoid overflow when addr_delta is large.  */
  if (addr_delta < 256 + MAX_SPECIAL_ADDR_DELTA)
    {
      /* Try using a special opcode.  */
      opcode = tmp + addr_delta * DWARF2_LINE_RANGE;
      if (opcode <= 255)
	{
	  *p++ = opcode;
	  goto done;
	}

      /* Try using DW_LNS_const_add_pc followed by special op.  */
      opcode = tmp + (addr_delta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
      if (opcode <= 255)
	{
	  *p++ = DW_LNS_const_add_pc;
	  *p++ = opcode;
	  goto done;
	}
    }

  /* Otherwise use DW_LNS_advance_pc.  */
  *p++ = DW_LNS_advance_pc;
  p += output_leb128 (p, addr_delta, 0);

  if (need_copy)
    *p++ = DW_LNS_copy;
  else
    *p++ = tmp;

 done:
  assert (p == end);
}

/* Handy routine to combine calls to the above two routines.  */

static void
out_inc_line_addr (int line_delta, addressT addr_delta)
{
  int len = size_inc_line_addr (line_delta, addr_delta);
  emit_inc_line_addr (line_delta, addr_delta, frag_more (len), len);
}

/* Write out an alternative form of line and address skips using
   DW_LNS_fixed_advance_pc opcodes.  This uses more space than the default
   line and address information, but it helps support linker relaxation that
   changes the code offsets.  */

static void
out_fixed_inc_line_addr (int line_delta, symbolS *to_sym, symbolS *from_sym)
{
  expressionS expr;

  /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence.  */
  if (line_delta == INT_MAX)
    {
      out_opcode (DW_LNS_fixed_advance_pc);
      expr.X_op = O_subtract;
      expr.X_add_symbol = to_sym;
      expr.X_op_symbol = from_sym;
      expr.X_add_number = 0;
      emit_expr (&expr, 2);

      out_opcode (DW_LNS_extended_op);
      out_byte (1);
      out_opcode (DW_LNE_end_sequence);
      return;
    }

  out_opcode (DW_LNS_advance_line);
  out_sleb128 (line_delta);

  out_opcode (DW_LNS_fixed_advance_pc);
  expr.X_op = O_subtract;
  expr.X_add_symbol = to_sym;
  expr.X_op_symbol = from_sym;
  expr.X_add_number = 0;
  emit_expr (&expr, 2);

  out_opcode (DW_LNS_copy);
}

/* Generate a variant frag that we can use to relax address/line
   increments between fragments of the target segment.  */

static void
relax_inc_line_addr (int line_delta, symbolS *to_sym, symbolS *from_sym)
{
  expressionS expr;
  int max_chars;

  expr.X_op = O_subtract;
  expr.X_add_symbol = to_sym;
  expr.X_op_symbol = from_sym;
  expr.X_add_number = 0;

  /* The maximum size of the frag is the line delta with a maximum
     sized address delta.  */
  max_chars = size_inc_line_addr (line_delta, -DWARF2_LINE_MIN_INSN_LENGTH);

  frag_var (rs_dwarf2dbg, max_chars, max_chars, 1,
	    make_expr_symbol (&expr), line_delta, NULL);
}

/* The function estimates the size of a rs_dwarf2dbg variant frag
   based on the current values of the symbols.  It is called before
   the relaxation loop.  We set fr_subtype to the expected length.  */

int
dwarf2dbg_estimate_size_before_relax (fragS *frag)
{
  offsetT addr_delta;
  int size;

  addr_delta = resolve_symbol_value (frag->fr_symbol);
  size = size_inc_line_addr (frag->fr_offset, addr_delta);

  frag->fr_subtype = size;

  return size;
}

/* This function relaxes a rs_dwarf2dbg variant frag based on the
   current values of the symbols.  fr_subtype is the current length
   of the frag.  This returns the change in frag length.  */

int
dwarf2dbg_relax_frag (fragS *frag)
{
  int old_size, new_size;

  old_size = frag->fr_subtype;
  new_size = dwarf2dbg_estimate_size_before_relax (frag);

  return new_size - old_size;
}

/* This function converts a rs_dwarf2dbg variant frag into a normal
   fill frag.  This is called after all relaxation has been done.
   fr_subtype will be the desired length of the frag.  */

void
dwarf2dbg_convert_frag (fragS *frag)
{
  offsetT addr_diff;

  addr_diff = resolve_symbol_value (frag->fr_symbol);

  /* fr_var carries the max_chars that we created the fragment with.
     fr_subtype carries the current expected length.  We must, of
     course, have allocated enough memory earlier.  */
  assert (frag->fr_var >= (int) frag->fr_subtype);

  emit_inc_line_addr (frag->fr_offset, addr_diff,
		      frag->fr_literal + frag->fr_fix, frag->fr_subtype);

  frag->fr_fix += frag->fr_subtype;
  frag->fr_type = rs_fill;
  frag->fr_var = 0;
  frag->fr_offset = 0;
}

/* Generate .debug_line content for the chain of line number entries
   beginning at E, for segment SEG.  */

static void
process_entries (segT seg, struct line_entry *e)
{
  unsigned filenum = 1;
  unsigned line = 1;
  unsigned column = 0;
  unsigned isa = 0;
  unsigned flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
  fragS *last_frag = NULL, *frag;
  addressT last_frag_ofs = 0, frag_ofs;
  symbolS *last_lab = NULL, *lab;
  struct line_entry *next;

  do
    {
      int line_delta;

      if (filenum != e->loc.filenum)
	{
	  filenum = e->loc.filenum;
	  out_opcode (DW_LNS_set_file);
	  out_uleb128 (filenum);
	}

      if (column != e->loc.column)
	{
	  column = e->loc.column;
	  out_opcode (DW_LNS_set_column);
	  out_uleb128 (column);
	}

      if (isa != e->loc.isa)
	{
	  isa = e->loc.isa;
	  out_opcode (DW_LNS_set_isa);
	  out_uleb128 (isa);
	}

      if ((e->loc.flags ^ flags) & DWARF2_FLAG_IS_STMT)
	{
	  flags = e->loc.flags;
	  out_opcode (DW_LNS_negate_stmt);
	}

      if (e->loc.flags & DWARF2_FLAG_BASIC_BLOCK)
	out_opcode (DW_LNS_set_basic_block);

      if (e->loc.flags & DWARF2_FLAG_PROLOGUE_END)
	out_opcode (DW_LNS_set_prologue_end);

      if (e->loc.flags & DWARF2_FLAG_EPILOGUE_BEGIN)
	out_opcode (DW_LNS_set_epilogue_begin);

      /* Don't try to optimize away redundant entries; gdb wants two
	 entries for a function where the code starts on the same line as
	 the {, and there's no way to identify that case here.  Trust gcc
	 to optimize appropriately.  */
      line_delta = e->loc.line - line;
      lab = e->label;
      frag = symbol_get_frag (lab);
      frag_ofs = S_GET_VALUE (lab);

      if (last_frag == NULL)
	{
	  out_set_addr (lab);
	  out_inc_line_addr (line_delta, 0);
	}
      else if (DWARF2_USE_FIXED_ADVANCE_PC)
	out_fixed_inc_line_addr (line_delta, lab, last_lab);
      else if (frag == last_frag)
	out_inc_line_addr (line_delta, frag_ofs - last_frag_ofs);
      else
	relax_inc_line_addr (line_delta, lab, last_lab);

      line = e->loc.line;
      last_lab = lab;
      last_frag = frag;
      last_frag_ofs = frag_ofs;

      next = e->next;
      free (e);
      e = next;
    }
  while (e);

  /* Emit a DW_LNE_end_sequence for the end of the section.  */
  frag = last_frag_for_seg (seg);
  frag_ofs = get_frag_fix (frag, seg);
  if (DWARF2_USE_FIXED_ADVANCE_PC)
    {
      lab = symbol_temp_new (seg, frag_ofs, frag);
      out_fixed_inc_line_addr (INT_MAX, lab, last_lab);
    }
  else if (frag == last_frag)
    out_inc_line_addr (INT_MAX, frag_ofs - last_frag_ofs);
  else
    {
      lab = symbol_temp_new (seg, frag_ofs, frag);
      relax_inc_line_addr (INT_MAX, lab, last_lab);
    }
}

/* Emit the directory and file tables for .debug_line.  */

static void
out_file_list (void)
{
  size_t size;
  const char *dir;
  char *cp;
  unsigned int i;

  /* Emit directory list.  */
  for (i = 1; i < dirs_in_use; ++i)
    {
      dir = remap_debug_filename (dirs[i]);
      size = strlen (dir) + 1;
      cp = frag_more (size);
      memcpy (cp, dir, size);
    }
  /* Terminate it.  */
  out_byte ('\0');

  for (i = 1; i < files_in_use; ++i)
    {
      if (files[i].filename == NULL)
	{
	  as_bad (_("unassigned file number %ld"), (long) i);
	  /* Prevent a crash later, particularly for file 1.  */
	  files[i].filename = "";
	  continue;
	}

      size = strlen (files[i].filename) + 1;
      cp = frag_more (size);
      memcpy (cp, files[i].filename, size);

      out_uleb128 (files[i].dir);	/* directory number */
      out_uleb128 (0);			/* last modification timestamp */
      out_uleb128 (0);			/* filesize */
    }

  /* Terminate filename list.  */
  out_byte (0);
}

/* Emit the collected .debug_line data.  */

static void
out_debug_line (segT line_seg)
{
  expressionS expr;
  symbolS *line_start;
  symbolS *prologue_end;
  symbolS *line_end;
  struct line_seg *s;
  enum dwarf2_format d2f;
  int sizeof_offset;

  subseg_set (line_seg, 0);

  line_start = symbol_temp_new_now ();
  prologue_end = symbol_temp_make ();
  line_end = symbol_temp_make ();

  /* Total length of the information for this compilation unit.  */
  expr.X_op = O_subtract;
  expr.X_add_symbol = line_end;
  expr.X_op_symbol = line_start;

  d2f = DWARF2_FORMAT ();
  if (d2f == dwarf2_format_32bit)
    {
      expr.X_add_number = -4;
      emit_expr (&expr, 4);
      sizeof_offset = 4;
    }
  else if (d2f == dwarf2_format_64bit)
    {
      expr.X_add_number = -12;
      out_four (-1);
      emit_expr (&expr, 8);
      sizeof_offset = 8;
    }
  else if (d2f == dwarf2_format_64bit_irix)
    {
      expr.X_add_number = -8;
      emit_expr (&expr, 8);
      sizeof_offset = 8;
    }
  else
    {
      as_fatal (_("internal error: unknown dwarf2 format"));
    }

  /* Version.  */
  out_two (2);

  /* Length of the prologue following this length.  */
  expr.X_op = O_subtract;
  expr.X_add_symbol = prologue_end;
  expr.X_op_symbol = line_start;
  expr.X_add_number = - (4 + 2 + 4);
  emit_expr (&expr, sizeof_offset);

  /* Parameters of the state machine.  */
  out_byte (DWARF2_LINE_MIN_INSN_LENGTH);
  out_byte (DWARF2_LINE_DEFAULT_IS_STMT);
  out_byte (DWARF2_LINE_BASE);
  out_byte (DWARF2_LINE_RANGE);
  out_byte (DWARF2_LINE_OPCODE_BASE);

  /* Standard opcode lengths.  */
  out_byte (0);			/* DW_LNS_copy */
  out_byte (1);			/* DW_LNS_advance_pc */
  out_byte (1);			/* DW_LNS_advance_line */
  out_byte (1);			/* DW_LNS_set_file */
  out_byte (1);			/* DW_LNS_set_column */
  out_byte (0);			/* DW_LNS_negate_stmt */
  out_byte (0);			/* DW_LNS_set_basic_block */
  out_byte (0);			/* DW_LNS_const_add_pc */
  out_byte (1);			/* DW_LNS_fixed_advance_pc */
  out_byte (0);			/* DW_LNS_set_prologue_end */
  out_byte (0);			/* DW_LNS_set_epilogue_begin */
  out_byte (1);			/* DW_LNS_set_isa */

  out_file_list ();

  symbol_set_value_now (prologue_end);

  /* For each section, emit a statement program.  */
  for (s = all_segs; s; s = s->next)
    process_entries (s->seg, s->head->head);

  symbol_set_value_now (line_end);
}

static void
out_debug_ranges (segT ranges_seg)
{
  unsigned int addr_size = sizeof_address;
  struct line_seg *s;
  expressionS expr;
  unsigned int i;

  subseg_set (ranges_seg, 0);

  /* Base Address Entry.  */
  for (i = 0; i < addr_size; i++) 
    out_byte (0xff);
  for (i = 0; i < addr_size; i++) 
    out_byte (0);

  /* Range List Entry.  */
  for (s = all_segs; s; s = s->next)
    {
      fragS *frag;
      symbolS *beg, *end;

      frag = first_frag_for_seg (s->seg);
      beg = symbol_temp_new (s->seg, 0, frag);
      s->text_start = beg;

      frag = last_frag_for_seg (s->seg);
      end = symbol_temp_new (s->seg, get_frag_fix (frag, s->seg), frag);
      s->text_end = end;

      expr.X_op = O_symbol;
      expr.X_add_symbol = beg;
      expr.X_add_number = 0;
      emit_expr (&expr, addr_size);

      expr.X_op = O_symbol;
      expr.X_add_symbol = end;
      expr.X_add_number = 0;
      emit_expr (&expr, addr_size);
    }

  /* End of Range Entry.   */
  for (i = 0; i < addr_size; i++) 
    out_byte (0);
  for (i = 0; i < addr_size; i++) 
    out_byte (0);
}

/* Emit data for .debug_aranges.  */

static void
out_debug_aranges (segT aranges_seg, segT info_seg)
{
  unsigned int addr_size = sizeof_address;
  addressT size, skip;
  struct line_seg *s;
  expressionS expr;
  char *p;

  size = 4 + 2 + 4 + 1 + 1;

  skip = 2 * addr_size - (size & (2 * addr_size - 1));
  if (skip == 2 * addr_size)
    skip = 0;
  size += skip;

  for (s = all_segs; s; s = s->next)
    size += 2 * addr_size;

  size += 2 * addr_size;

  subseg_set (aranges_seg, 0);

  /* Length of the compilation unit.  */
  out_four (size - 4);

  /* Version.  */
  out_two (2);

  /* Offset to .debug_info.  */
  /* ??? sizeof_offset */
  TC_DWARF2_EMIT_OFFSET (section_symbol (info_seg), 4);

  /* Size of an address (offset portion).  */
  out_byte (addr_size);

  /* Size of a segment descriptor.  */
  out_byte (0);

  /* Align the header.  */
  if (skip)
    frag_align (ffs (2 * addr_size) - 1, 0, 0);

  for (s = all_segs; s; s = s->next)
    {
      fragS *frag;
      symbolS *beg, *end;

      frag = first_frag_for_seg (s->seg);
      beg = symbol_temp_new (s->seg, 0, frag);
      s->text_start = beg;

      frag = last_frag_for_seg (s->seg);
      end = symbol_temp_new (s->seg, get_frag_fix (frag, s->seg), frag);
      s->text_end = end;

      expr.X_op = O_symbol;
      expr.X_add_symbol = beg;
      expr.X_add_number = 0;
      emit_expr (&expr, addr_size);

      expr.X_op = O_subtract;
      expr.X_add_symbol = end;
      expr.X_op_symbol = beg;
      expr.X_add_number = 0;
      emit_expr (&expr, addr_size);
    }

  p = frag_more (2 * addr_size);
  md_number_to_chars (p, 0, addr_size);
  md_number_to_chars (p + addr_size, 0, addr_size);
}

/* Emit data for .debug_abbrev.  Note that this must be kept in
   sync with out_debug_info below.  */

static void
out_debug_abbrev (segT abbrev_seg)
{
  subseg_set (abbrev_seg, 0);

  out_uleb128 (1);
  out_uleb128 (DW_TAG_compile_unit);
  out_byte (DW_CHILDREN_no);
  out_abbrev (DW_AT_stmt_list, DW_FORM_data4);
  if (all_segs->next == NULL)
    {
      out_abbrev (DW_AT_low_pc, DW_FORM_addr);
      out_abbrev (DW_AT_high_pc, DW_FORM_addr);
    }
  else
    {
      if (DWARF2_FORMAT () == dwarf2_format_32bit)
	out_abbrev (DW_AT_ranges, DW_FORM_data4);
      else
	out_abbrev (DW_AT_ranges, DW_FORM_data8);
    }
  out_abbrev (DW_AT_name, DW_FORM_string);
  out_abbrev (DW_AT_comp_dir, DW_FORM_string);
  out_abbrev (DW_AT_producer, DW_FORM_string);
  out_abbrev (DW_AT_language, DW_FORM_data2);
  out_abbrev (0, 0);

  /* Terminate the abbreviations for this compilation unit.  */
  out_byte (0);
}

/* Emit a description of this compilation unit for .debug_info.  */

static void
out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT ranges_seg)
{
  char producer[128];
  const char *comp_dir;
  const char *dirname;
  expressionS expr;
  symbolS *info_start;
  symbolS *info_end;
  char *p;
  int len;
  enum dwarf2_format d2f;
  int sizeof_offset;

  subseg_set (info_seg, 0);

  info_start = symbol_temp_new_now ();
  info_end = symbol_temp_make ();

  /* Compilation Unit length.  */
  expr.X_op = O_subtract;
  expr.X_add_symbol = info_end;
  expr.X_op_symbol = info_start;

  d2f = DWARF2_FORMAT ();
  if (d2f == dwarf2_format_32bit)
    {
      expr.X_add_number = -4;
      emit_expr (&expr, 4);
      sizeof_offset = 4;
    }
  else if (d2f == dwarf2_format_64bit)
    {
      expr.X_add_number = -12;
      out_four (-1);
      emit_expr (&expr, 8);
      sizeof_offset = 8;
    }
  else if (d2f == dwarf2_format_64bit_irix)
    {
      expr.X_add_number = -8;
      emit_expr (&expr, 8);
      sizeof_offset = 8;
    }
  else
    {
      as_fatal (_("internal error: unknown dwarf2 format"));
    }

  /* DWARF version.  */
  out_two (2);

  /* .debug_abbrev offset */
  TC_DWARF2_EMIT_OFFSET (section_symbol (abbrev_seg), sizeof_offset);

  /* Target address size.  */
  out_byte (sizeof_address);

  /* DW_TAG_compile_unit DIE abbrev */
  out_uleb128 (1);

  /* DW_AT_stmt_list */
  /* ??? sizeof_offset */
  TC_DWARF2_EMIT_OFFSET (section_symbol (line_seg), 4);

  /* These two attributes are emitted if all of the code is contiguous.  */
  if (all_segs->next == NULL)
    {
      /* DW_AT_low_pc */
      expr.X_op = O_symbol;
      expr.X_add_symbol = all_segs->text_start;
      expr.X_add_number = 0;
      emit_expr (&expr, sizeof_address);

      /* DW_AT_high_pc */
      expr.X_op = O_symbol;
      expr.X_add_symbol = all_segs->text_end;
      expr.X_add_number = 0;
      emit_expr (&expr, sizeof_address);
    }
  else
    {
      /* This attribute is emitted if the code is disjoint.  */
      /* DW_AT_ranges.  */
      TC_DWARF2_EMIT_OFFSET (section_symbol (ranges_seg), sizeof_offset);
    }

  /* DW_AT_name.  We don't have the actual file name that was present
     on the command line, so assume files[1] is the main input file.
     We're not supposed to get called unless at least one line number
     entry was emitted, so this should always be defined.  */
  if (!files || files_in_use < 1)
    abort ();
  if (files[1].dir)
    {
      dirname = remap_debug_filename (dirs[files[1].dir]);
      len = strlen (dirname);
      p = frag_more (len + 1);
      memcpy (p, dirname, len);
      INSERT_DIR_SEPARATOR (p, len);
    }
  len = strlen (files[1].filename) + 1;
  p = frag_more (len);
  memcpy (p, files[1].filename, len);

  /* DW_AT_comp_dir */
  comp_dir = remap_debug_filename (getpwd ());
  len = strlen (comp_dir) + 1;
  p = frag_more (len);
  memcpy (p, comp_dir, len);

  /* DW_AT_producer */
  sprintf (producer, "GNU AS %s", VERSION);
  len = strlen (producer) + 1;
  p = frag_more (len);
  memcpy (p, producer, len);

  /* DW_AT_language.  Yes, this is probably not really MIPS, but the
     dwarf2 draft has no standard code for assembler.  */
  out_two (DW_LANG_Mips_Assembler);

  symbol_set_value_now (info_end);
}

/* Finish the dwarf2 debug sections.  We emit .debug.line if there
   were any .file/.loc directives, or --gdwarf2 was given, or if the
   file has a non-empty .debug_info section.  If we emit .debug_line,
   and the .debug_info section is empty, we also emit .debug_info,
   .debug_aranges and .debug_abbrev.  ALL_SEGS will be non-null if
   there were any .file/.loc directives, or --gdwarf2 was given and
   there were any located instructions emitted.  */

void
dwarf2_finish (void)
{
  segT line_seg;
  struct line_seg *s;
  segT info_seg;
  int emit_other_sections = 0;

  info_seg = bfd_get_section_by_name (stdoutput, ".debug_info");
  emit_other_sections = info_seg == NULL || !seg_not_empty_p (info_seg);

  if (!all_segs && emit_other_sections)
    /* There is no line information and no non-empty .debug_info
       section.  */
    return;

  /* Calculate the size of an address for the target machine.  */
  sizeof_address = DWARF2_ADDR_SIZE (stdoutput);

  /* Create and switch to the line number section.  */
  line_seg = subseg_new (".debug_line", 0);
  bfd_set_section_flags (stdoutput, line_seg, SEC_READONLY | SEC_DEBUGGING);

  /* For each subsection, chain the debug entries together.  */
  for (s = all_segs; s; s = s->next)
    {
      struct line_subseg *ss = s->head;
      struct line_entry **ptail = ss->ptail;

      while ((ss = ss->next) != NULL)
	{
	  *ptail = ss->head;
	  ptail = ss->ptail;
	}
    }

  out_debug_line (line_seg);

  /* If this is assembler generated line info, and there is no
     debug_info already, we need .debug_info and .debug_abbrev
     sections as well.  */
  if (emit_other_sections)
    {
      segT abbrev_seg;
      segT aranges_seg;
      segT ranges_seg;

      assert (all_segs);
      
      info_seg = subseg_new (".debug_info", 0);
      abbrev_seg = subseg_new (".debug_abbrev", 0);
      aranges_seg = subseg_new (".debug_aranges", 0);

      bfd_set_section_flags (stdoutput, info_seg,
			     SEC_READONLY | SEC_DEBUGGING);
      bfd_set_section_flags (stdoutput, abbrev_seg,
			     SEC_READONLY | SEC_DEBUGGING);
      bfd_set_section_flags (stdoutput, aranges_seg,
			     SEC_READONLY | SEC_DEBUGGING);

      record_alignment (aranges_seg, ffs (2 * sizeof_address) - 1);

      if (all_segs->next == NULL)
	ranges_seg = NULL;
      else
	{
	  ranges_seg = subseg_new (".debug_ranges", 0);
	  bfd_set_section_flags (stdoutput, ranges_seg, 
				 SEC_READONLY | SEC_DEBUGGING);
	  record_alignment (ranges_seg, ffs (2 * sizeof_address) - 1);
	  out_debug_ranges (ranges_seg);
	}

      out_debug_aranges (aranges_seg, info_seg);
      out_debug_abbrev (abbrev_seg);
      out_debug_info (info_seg, abbrev_seg, line_seg, ranges_seg);
    }
}