aboutsummaryrefslogtreecommitdiff
path: root/gdb/btrace.c
blob: b5c3c260b72c460aeab622e674555320112ca9aa (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
/* Branch trace support for GDB, the GNU debugger.

   Copyright (C) 2013-2014 Free Software Foundation, Inc.

   Contributed by Intel Corp. <markus.t.metzger@intel.com>

   This file is part of GDB.

   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "btrace.h"
#include "gdbthread.h"
#include "exceptions.h"
#include "inferior.h"
#include "target.h"
#include "record.h"
#include "symtab.h"
#include "disasm.h"
#include "source.h"
#include "filenames.h"
#include "xml-support.h"
#include "regcache.h"

/* Print a record debug message.  Use do ... while (0) to avoid ambiguities
   when used in if statements.  */

#define DEBUG(msg, args...)						\
  do									\
    {									\
      if (record_debug != 0)						\
        fprintf_unfiltered (gdb_stdlog,					\
			    "[btrace] " msg "\n", ##args);		\
    }									\
  while (0)

#define DEBUG_FTRACE(msg, args...) DEBUG ("[ftrace] " msg, ##args)

/* Return the function name of a recorded function segment for printing.
   This function never returns NULL.  */

static const char *
ftrace_print_function_name (const struct btrace_function *bfun)
{
  struct minimal_symbol *msym;
  struct symbol *sym;

  msym = bfun->msym;
  sym = bfun->sym;

  if (sym != NULL)
    return SYMBOL_PRINT_NAME (sym);

  if (msym != NULL)
    return MSYMBOL_PRINT_NAME (msym);

  return "<unknown>";
}

/* Return the file name of a recorded function segment for printing.
   This function never returns NULL.  */

static const char *
ftrace_print_filename (const struct btrace_function *bfun)
{
  struct symbol *sym;
  const char *filename;

  sym = bfun->sym;

  if (sym != NULL)
    filename = symtab_to_filename_for_display (sym->symtab);
  else
    filename = "<unknown>";

  return filename;
}

/* Return a string representation of the address of an instruction.
   This function never returns NULL.  */

static const char *
ftrace_print_insn_addr (const struct btrace_insn *insn)
{
  if (insn == NULL)
    return "<nil>";

  return core_addr_to_string_nz (insn->pc);
}

/* Print an ftrace debug status message.  */

static void
ftrace_debug (const struct btrace_function *bfun, const char *prefix)
{
  const char *fun, *file;
  unsigned int ibegin, iend;
  int lbegin, lend, level;

  fun = ftrace_print_function_name (bfun);
  file = ftrace_print_filename (bfun);
  level = bfun->level;

  lbegin = bfun->lbegin;
  lend = bfun->lend;

  ibegin = bfun->insn_offset;
  iend = ibegin + VEC_length (btrace_insn_s, bfun->insn);

  DEBUG_FTRACE ("%s: fun = %s, file = %s, level = %d, lines = [%d; %d], "
		"insn = [%u; %u)", prefix, fun, file, level, lbegin, lend,
		ibegin, iend);
}

/* Return non-zero if BFUN does not match MFUN and FUN,
   return zero otherwise.  */

static int
ftrace_function_switched (const struct btrace_function *bfun,
			  const struct minimal_symbol *mfun,
			  const struct symbol *fun)
{
  struct minimal_symbol *msym;
  struct symbol *sym;

  msym = bfun->msym;
  sym = bfun->sym;

  /* If the minimal symbol changed, we certainly switched functions.  */
  if (mfun != NULL && msym != NULL
      && strcmp (MSYMBOL_LINKAGE_NAME (mfun), MSYMBOL_LINKAGE_NAME (msym)) != 0)
    return 1;

  /* If the symbol changed, we certainly switched functions.  */
  if (fun != NULL && sym != NULL)
    {
      const char *bfname, *fname;

      /* Check the function name.  */
      if (strcmp (SYMBOL_LINKAGE_NAME (fun), SYMBOL_LINKAGE_NAME (sym)) != 0)
	return 1;

      /* Check the location of those functions, as well.  */
      bfname = symtab_to_fullname (sym->symtab);
      fname = symtab_to_fullname (fun->symtab);
      if (filename_cmp (fname, bfname) != 0)
	return 1;
    }

  /* If we lost symbol information, we switched functions.  */
  if (!(msym == NULL && sym == NULL) && mfun == NULL && fun == NULL)
    return 1;

  /* If we gained symbol information, we switched functions.  */
  if (msym == NULL && sym == NULL && !(mfun == NULL && fun == NULL))
    return 1;

  return 0;
}

/* Return non-zero if we should skip this file when generating the function
   call history, zero otherwise.
   We would want to do that if, say, a macro that is defined in another file
   is expanded in this function.  */

static int
ftrace_skip_file (const struct btrace_function *bfun, const char *fullname)
{
  struct symbol *sym;
  const char *bfile;

  sym = bfun->sym;
  if (sym == NULL)
    return 1;

  bfile = symtab_to_fullname (sym->symtab);

  return (filename_cmp (bfile, fullname) != 0);
}

/* Allocate and initialize a new branch trace function segment.
   PREV is the chronologically preceding function segment.
   MFUN and FUN are the symbol information we have for this function.  */

static struct btrace_function *
ftrace_new_function (struct btrace_function *prev,
		     struct minimal_symbol *mfun,
		     struct symbol *fun)
{
  struct btrace_function *bfun;

  bfun = xzalloc (sizeof (*bfun));

  bfun->msym = mfun;
  bfun->sym = fun;
  bfun->flow.prev = prev;

  /* We start with the identities of min and max, respectively.  */
  bfun->lbegin = INT_MAX;
  bfun->lend = INT_MIN;

  if (prev == NULL)
    {
      /* Start counting at one.  */
      bfun->number = 1;
      bfun->insn_offset = 1;
    }
  else
    {
      gdb_assert (prev->flow.next == NULL);
      prev->flow.next = bfun;

      bfun->number = prev->number + 1;
      bfun->insn_offset = (prev->insn_offset
			   + VEC_length (btrace_insn_s, prev->insn));
    }

  return bfun;
}

/* Update the UP field of a function segment.  */

static void
ftrace_update_caller (struct btrace_function *bfun,
		      struct btrace_function *caller,
		      enum btrace_function_flag flags)
{
  if (bfun->up != NULL)
    ftrace_debug (bfun, "updating caller");

  bfun->up = caller;
  bfun->flags = flags;

  ftrace_debug (bfun, "set caller");
}

/* Fix up the caller for all segments of a function.  */

static void
ftrace_fixup_caller (struct btrace_function *bfun,
		     struct btrace_function *caller,
		     enum btrace_function_flag flags)
{
  struct btrace_function *prev, *next;

  ftrace_update_caller (bfun, caller, flags);

  /* Update all function segments belonging to the same function.  */
  for (prev = bfun->segment.prev; prev != NULL; prev = prev->segment.prev)
    ftrace_update_caller (prev, caller, flags);

  for (next = bfun->segment.next; next != NULL; next = next->segment.next)
    ftrace_update_caller (next, caller, flags);
}

/* Add a new function segment for a call.
   CALLER is the chronologically preceding function segment.
   MFUN and FUN are the symbol information we have for this function.  */

static struct btrace_function *
ftrace_new_call (struct btrace_function *caller,
		 struct minimal_symbol *mfun,
		 struct symbol *fun)
{
  struct btrace_function *bfun;

  bfun = ftrace_new_function (caller, mfun, fun);
  bfun->up = caller;
  bfun->level = caller->level + 1;

  ftrace_debug (bfun, "new call");

  return bfun;
}

/* Add a new function segment for a tail call.
   CALLER is the chronologically preceding function segment.
   MFUN and FUN are the symbol information we have for this function.  */

static struct btrace_function *
ftrace_new_tailcall (struct btrace_function *caller,
		     struct minimal_symbol *mfun,
		     struct symbol *fun)
{
  struct btrace_function *bfun;

  bfun = ftrace_new_function (caller, mfun, fun);
  bfun->up = caller;
  bfun->level = caller->level + 1;
  bfun->flags |= BFUN_UP_LINKS_TO_TAILCALL;

  ftrace_debug (bfun, "new tail call");

  return bfun;
}

/* Find the innermost caller in the back trace of BFUN with MFUN/FUN
   symbol information.  */

static struct btrace_function *
ftrace_find_caller (struct btrace_function *bfun,
		    struct minimal_symbol *mfun,
		    struct symbol *fun)
{
  for (; bfun != NULL; bfun = bfun->up)
    {
      /* Skip functions with incompatible symbol information.  */
      if (ftrace_function_switched (bfun, mfun, fun))
	continue;

      /* This is the function segment we're looking for.  */
      break;
    }

  return bfun;
}

/* Find the innermost caller in the back trace of BFUN, skipping all
   function segments that do not end with a call instruction (e.g.
   tail calls ending with a jump).  */

static struct btrace_function *
ftrace_find_call (struct gdbarch *gdbarch, struct btrace_function *bfun)
{
  for (; bfun != NULL; bfun = bfun->up)
    {
      struct btrace_insn *last;
      CORE_ADDR pc;

      /* We do not allow empty function segments.  */
      gdb_assert (!VEC_empty (btrace_insn_s, bfun->insn));

      last = VEC_last (btrace_insn_s, bfun->insn);
      pc = last->pc;

      if (gdbarch_insn_is_call (gdbarch, pc))
	break;
    }

  return bfun;
}

/* Add a continuation segment for a function into which we return.
   PREV is the chronologically preceding function segment.
   MFUN and FUN are the symbol information we have for this function.  */

static struct btrace_function *
ftrace_new_return (struct gdbarch *gdbarch,
		   struct btrace_function *prev,
		   struct minimal_symbol *mfun,
		   struct symbol *fun)
{
  struct btrace_function *bfun, *caller;

  bfun = ftrace_new_function (prev, mfun, fun);

  /* It is important to start at PREV's caller.  Otherwise, we might find
     PREV itself, if PREV is a recursive function.  */
  caller = ftrace_find_caller (prev->up, mfun, fun);
  if (caller != NULL)
    {
      /* The caller of PREV is the preceding btrace function segment in this
	 function instance.  */
      gdb_assert (caller->segment.next == NULL);

      caller->segment.next = bfun;
      bfun->segment.prev = caller;

      /* Maintain the function level.  */
      bfun->level = caller->level;

      /* Maintain the call stack.  */
      bfun->up = caller->up;
      bfun->flags = caller->flags;

      ftrace_debug (bfun, "new return");
    }
  else
    {
      /* We did not find a caller.  This could mean that something went
	 wrong or that the call is simply not included in the trace.  */

      /* Let's search for some actual call.  */
      caller = ftrace_find_call (gdbarch, prev->up);
      if (caller == NULL)
	{
	  /* There is no call in PREV's back trace.  We assume that the
	     branch trace did not include it.  */

	  /* Let's find the topmost call function - this skips tail calls.  */
	  while (prev->up != NULL)
	    prev = prev->up;

	  /* We maintain levels for a series of returns for which we have
	     not seen the calls.
	     We start at the preceding function's level in case this has
	     already been a return for which we have not seen the call.
	     We start at level 0 otherwise, to handle tail calls correctly.  */
	  bfun->level = min (0, prev->level) - 1;

	  /* Fix up the call stack for PREV.  */
	  ftrace_fixup_caller (prev, bfun, BFUN_UP_LINKS_TO_RET);

	  ftrace_debug (bfun, "new return - no caller");
	}
      else
	{
	  /* There is a call in PREV's back trace to which we should have
	     returned.  Let's remain at this level.  */
	  bfun->level = prev->level;

	  ftrace_debug (bfun, "new return - unknown caller");
	}
    }

  return bfun;
}

/* Add a new function segment for a function switch.
   PREV is the chronologically preceding function segment.
   MFUN and FUN are the symbol information we have for this function.  */

static struct btrace_function *
ftrace_new_switch (struct btrace_function *prev,
		   struct minimal_symbol *mfun,
		   struct symbol *fun)
{
  struct btrace_function *bfun;

  /* This is an unexplained function switch.  The call stack will likely
     be wrong at this point.  */
  bfun = ftrace_new_function (prev, mfun, fun);

  /* We keep the function level.  */
  bfun->level = prev->level;

  ftrace_debug (bfun, "new switch");

  return bfun;
}

/* Update BFUN with respect to the instruction at PC.  This may create new
   function segments.
   Return the chronologically latest function segment, never NULL.  */

static struct btrace_function *
ftrace_update_function (struct gdbarch *gdbarch,
			struct btrace_function *bfun, CORE_ADDR pc)
{
  struct bound_minimal_symbol bmfun;
  struct minimal_symbol *mfun;
  struct symbol *fun;
  struct btrace_insn *last;

  /* Try to determine the function we're in.  We use both types of symbols
     to avoid surprises when we sometimes get a full symbol and sometimes
     only a minimal symbol.  */
  fun = find_pc_function (pc);
  bmfun = lookup_minimal_symbol_by_pc (pc);
  mfun = bmfun.minsym;

  if (fun == NULL && mfun == NULL)
    DEBUG_FTRACE ("no symbol at %s", core_addr_to_string_nz (pc));

  /* If we didn't have a function before, we create one.  */
  if (bfun == NULL)
    return ftrace_new_function (bfun, mfun, fun);

  /* Check the last instruction, if we have one.
     We do this check first, since it allows us to fill in the call stack
     links in addition to the normal flow links.  */
  last = NULL;
  if (!VEC_empty (btrace_insn_s, bfun->insn))
    last = VEC_last (btrace_insn_s, bfun->insn);

  if (last != NULL)
    {
      CORE_ADDR lpc;

      lpc = last->pc;

      /* Check for returns.  */
      if (gdbarch_insn_is_ret (gdbarch, lpc))
	return ftrace_new_return (gdbarch, bfun, mfun, fun);

      /* Check for calls.  */
      if (gdbarch_insn_is_call (gdbarch, lpc))
	{
	  int size;

	  size = gdb_insn_length (gdbarch, lpc);

	  /* Ignore calls to the next instruction.  They are used for PIC.  */
	  if (lpc + size != pc)
	    return ftrace_new_call (bfun, mfun, fun);
	}
    }

  /* Check if we're switching functions for some other reason.  */
  if (ftrace_function_switched (bfun, mfun, fun))
    {
      DEBUG_FTRACE ("switching from %s in %s at %s",
		    ftrace_print_insn_addr (last),
		    ftrace_print_function_name (bfun),
		    ftrace_print_filename (bfun));

      if (last != NULL)
	{
	  CORE_ADDR start, lpc;

	  start = get_pc_function_start (pc);

	  /* If we can't determine the function for PC, we treat a jump at
	     the end of the block as tail call.  */
	  if (start == 0)
	    start = pc;

	  lpc = last->pc;

	  /* Jumps indicate optimized tail calls.  */
	  if (start == pc && gdbarch_insn_is_jump (gdbarch, lpc))
	    return ftrace_new_tailcall (bfun, mfun, fun);
	}

      return ftrace_new_switch (bfun, mfun, fun);
    }

  return bfun;
}

/* Update BFUN's source range with respect to the instruction at PC.  */

static void
ftrace_update_lines (struct btrace_function *bfun, CORE_ADDR pc)
{
  struct symtab_and_line sal;
  const char *fullname;

  sal = find_pc_line (pc, 0);
  if (sal.symtab == NULL || sal.line == 0)
    {
      DEBUG_FTRACE ("no lines at %s", core_addr_to_string_nz (pc));
      return;
    }

  /* Check if we switched files.  This could happen if, say, a macro that
     is defined in another file is expanded here.  */
  fullname = symtab_to_fullname (sal.symtab);
  if (ftrace_skip_file (bfun, fullname))
    {
      DEBUG_FTRACE ("ignoring file at %s, file=%s",
		    core_addr_to_string_nz (pc), fullname);
      return;
    }

  /* Update the line range.  */
  bfun->lbegin = min (bfun->lbegin, sal.line);
  bfun->lend = max (bfun->lend, sal.line);

  if (record_debug > 1)
    ftrace_debug (bfun, "update lines");
}

/* Add the instruction at PC to BFUN's instructions.  */

static void
ftrace_update_insns (struct btrace_function *bfun, CORE_ADDR pc)
{
  struct btrace_insn *insn;

  insn = VEC_safe_push (btrace_insn_s, bfun->insn, NULL);
  insn->pc = pc;

  if (record_debug > 1)
    ftrace_debug (bfun, "update insn");
}

/* Compute the function branch trace from a block branch trace BTRACE for
   a thread given by BTINFO.  */

static void
btrace_compute_ftrace (struct btrace_thread_info *btinfo,
		       VEC (btrace_block_s) *btrace)
{
  struct btrace_function *begin, *end;
  struct gdbarch *gdbarch;
  unsigned int blk;
  int level;

  DEBUG ("compute ftrace");

  gdbarch = target_gdbarch ();
  begin = btinfo->begin;
  end = btinfo->end;
  level = begin != NULL ? -btinfo->level : INT_MAX;
  blk = VEC_length (btrace_block_s, btrace);

  while (blk != 0)
    {
      btrace_block_s *block;
      CORE_ADDR pc;

      blk -= 1;

      block = VEC_index (btrace_block_s, btrace, blk);
      pc = block->begin;

      for (;;)
	{
	  int size;

	  /* We should hit the end of the block.  Warn if we went too far.  */
	  if (block->end < pc)
	    {
	      warning (_("Recorded trace may be corrupted around %s."),
		       core_addr_to_string_nz (pc));
	      break;
	    }

	  end = ftrace_update_function (gdbarch, end, pc);
	  if (begin == NULL)
	    begin = end;

	  /* Maintain the function level offset.
	     For all but the last block, we do it here.  */
	  if (blk != 0)
	    level = min (level, end->level);

	  ftrace_update_insns (end, pc);
	  ftrace_update_lines (end, pc);

	  /* We're done once we pushed the instruction at the end.  */
	  if (block->end == pc)
	    break;

	  size = gdb_insn_length (gdbarch, pc);

	  /* Make sure we terminate if we fail to compute the size.  */
	  if (size <= 0)
	    {
	      warning (_("Recorded trace may be incomplete around %s."),
		       core_addr_to_string_nz (pc));
	      break;
	    }

	  pc += size;

	  /* Maintain the function level offset.
	     For the last block, we do it here to not consider the last
	     instruction.
	     Since the last instruction corresponds to the current instruction
	     and is not really part of the execution history, it shouldn't
	     affect the level.  */
	  if (blk == 0)
	    level = min (level, end->level);
	}
    }

  btinfo->begin = begin;
  btinfo->end = end;

  /* LEVEL is the minimal function level of all btrace function segments.
     Define the global level offset to -LEVEL so all function levels are
     normalized to start at zero.  */
  btinfo->level = -level;
}

/* Add an entry for the current PC.  */

static void
btrace_add_pc (struct thread_info *tp)
{
  VEC (btrace_block_s) *btrace;
  struct btrace_block *block;
  struct regcache *regcache;
  struct cleanup *cleanup;
  CORE_ADDR pc;

  regcache = get_thread_regcache (tp->ptid);
  pc = regcache_read_pc (regcache);

  btrace = NULL;
  cleanup = make_cleanup (VEC_cleanup (btrace_block_s), &btrace);

  block = VEC_safe_push (btrace_block_s, btrace, NULL);
  block->begin = pc;
  block->end = pc;

  btrace_compute_ftrace (&tp->btrace, btrace);

  do_cleanups (cleanup);
}

/* See btrace.h.  */

void
btrace_enable (struct thread_info *tp)
{
  if (tp->btrace.target != NULL)
    return;

  if (!target_supports_btrace ())
    error (_("Target does not support branch tracing."));

  DEBUG ("enable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));

  tp->btrace.target = target_enable_btrace (tp->ptid);

  /* Add an entry for the current PC so we start tracing from where we
     enabled it.  */
  if (tp->btrace.target != NULL)
    btrace_add_pc (tp);
}

/* See btrace.h.  */

void
btrace_disable (struct thread_info *tp)
{
  struct btrace_thread_info *btp = &tp->btrace;
  int errcode = 0;

  if (btp->target == NULL)
    return;

  DEBUG ("disable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));

  target_disable_btrace (btp->target);
  btp->target = NULL;

  btrace_clear (tp);
}

/* See btrace.h.  */

void
btrace_teardown (struct thread_info *tp)
{
  struct btrace_thread_info *btp = &tp->btrace;
  int errcode = 0;

  if (btp->target == NULL)
    return;

  DEBUG ("teardown thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));

  target_teardown_btrace (btp->target);
  btp->target = NULL;

  btrace_clear (tp);
}

/* Adjust the block trace in order to stitch old and new trace together.
   BTRACE is the new delta trace between the last and the current stop.
   BTINFO is the old branch trace until the last stop.
   May modify BTRACE as well as the existing trace in BTINFO.
   Return 0 on success, -1 otherwise.  */

static int
btrace_stitch_trace (VEC (btrace_block_s) **btrace,
		     const struct btrace_thread_info *btinfo)
{
  struct btrace_function *last_bfun;
  struct btrace_insn *last_insn;
  btrace_block_s *first_new_block;

  /* If we don't have trace, there's nothing to do.  */
  if (VEC_empty (btrace_block_s, *btrace))
    return 0;

  last_bfun = btinfo->end;
  gdb_assert (last_bfun != NULL);

  /* Beware that block trace starts with the most recent block, so the
     chronologically first block in the new trace is the last block in
     the new trace's block vector.  */
  first_new_block = VEC_last (btrace_block_s, *btrace);
  last_insn = VEC_last (btrace_insn_s, last_bfun->insn);

  /* If the current PC at the end of the block is the same as in our current
     trace, there are two explanations:
       1. we executed the instruction and some branch brought us back.
       2. we have not made any progress.
     In the first case, the delta trace vector should contain at least two
     entries.
     In the second case, the delta trace vector should contain exactly one
     entry for the partial block containing the current PC.  Remove it.  */
  if (first_new_block->end == last_insn->pc
      && VEC_length (btrace_block_s, *btrace) == 1)
    {
      VEC_pop (btrace_block_s, *btrace);
      return 0;
    }

  DEBUG ("stitching %s to %s", ftrace_print_insn_addr (last_insn),
	 core_addr_to_string_nz (first_new_block->end));

  /* Do a simple sanity check to make sure we don't accidentally end up
     with a bad block.  This should not occur in practice.  */
  if (first_new_block->end < last_insn->pc)
    {
      warning (_("Error while trying to read delta trace.  Falling back to "
		 "a full read."));
      return -1;
    }

  /* We adjust the last block to start at the end of our current trace.  */
  gdb_assert (first_new_block->begin == 0);
  first_new_block->begin = last_insn->pc;

  /* We simply pop the last insn so we can insert it again as part of
     the normal branch trace computation.
     Since instruction iterators are based on indices in the instructions
     vector, we don't leave any pointers dangling.  */
  DEBUG ("pruning insn at %s for stitching",
	 ftrace_print_insn_addr (last_insn));

  VEC_pop (btrace_insn_s, last_bfun->insn);

  /* The instructions vector may become empty temporarily if this has
     been the only instruction in this function segment.
     This violates the invariant but will be remedied shortly by
     btrace_compute_ftrace when we add the new trace.  */
  return 0;
}

/* Clear the branch trace histories in BTINFO.  */

static void
btrace_clear_history (struct btrace_thread_info *btinfo)
{
  xfree (btinfo->insn_history);
  xfree (btinfo->call_history);
  xfree (btinfo->replay);

  btinfo->insn_history = NULL;
  btinfo->call_history = NULL;
  btinfo->replay = NULL;
}

/* See btrace.h.  */

void
btrace_fetch (struct thread_info *tp)
{
  struct btrace_thread_info *btinfo;
  struct btrace_target_info *tinfo;
  VEC (btrace_block_s) *btrace;
  struct cleanup *cleanup;
  int errcode;

  DEBUG ("fetch thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));

  btrace = NULL;
  btinfo = &tp->btrace;
  tinfo = btinfo->target;
  if (tinfo == NULL)
    return;

  /* There's no way we could get new trace while replaying.
     On the other hand, delta trace would return a partial record with the
     current PC, which is the replay PC, not the last PC, as expected.  */
  if (btinfo->replay != NULL)
    return;

  cleanup = make_cleanup (VEC_cleanup (btrace_block_s), &btrace);

  /* Let's first try to extend the trace we already have.  */
  if (btinfo->end != NULL)
    {
      errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_DELTA);
      if (errcode == 0)
	{
	  /* Success.  Let's try to stitch the traces together.  */
	  errcode = btrace_stitch_trace (&btrace, btinfo);
	}
      else
	{
	  /* We failed to read delta trace.  Let's try to read new trace.  */
	  errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_NEW);

	  /* If we got any new trace, discard what we have.  */
	  if (errcode == 0 && !VEC_empty (btrace_block_s, btrace))
	    btrace_clear (tp);
	}

      /* If we were not able to read the trace, we start over.  */
      if (errcode != 0)
	{
	  btrace_clear (tp);
	  errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_ALL);
	}
    }
  else
    errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_ALL);

  /* If we were not able to read the branch trace, signal an error.  */
  if (errcode != 0)
    error (_("Failed to read branch trace."));

  /* Compute the trace, provided we have any.  */
  if (!VEC_empty (btrace_block_s, btrace))
    {
      btrace_clear_history (btinfo);
      btrace_compute_ftrace (btinfo, btrace);
    }

  do_cleanups (cleanup);
}

/* See btrace.h.  */

void
btrace_clear (struct thread_info *tp)
{
  struct btrace_thread_info *btinfo;
  struct btrace_function *it, *trash;

  DEBUG ("clear thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));

  /* Make sure btrace frames that may hold a pointer into the branch
     trace data are destroyed.  */
  reinit_frame_cache ();

  btinfo = &tp->btrace;

  it = btinfo->begin;
  while (it != NULL)
    {
      trash = it;
      it = it->flow.next;

      xfree (trash);
    }

  btinfo->begin = NULL;
  btinfo->end = NULL;

  btrace_clear_history (btinfo);
}

/* See btrace.h.  */

void
btrace_free_objfile (struct objfile *objfile)
{
  struct thread_info *tp;

  DEBUG ("free objfile");

  ALL_NON_EXITED_THREADS (tp)
    btrace_clear (tp);
}

#if defined (HAVE_LIBEXPAT)

/* Check the btrace document version.  */

static void
check_xml_btrace_version (struct gdb_xml_parser *parser,
			  const struct gdb_xml_element *element,
			  void *user_data, VEC (gdb_xml_value_s) *attributes)
{
  const char *version = xml_find_attribute (attributes, "version")->value;

  if (strcmp (version, "1.0") != 0)
    gdb_xml_error (parser, _("Unsupported btrace version: \"%s\""), version);
}

/* Parse a btrace "block" xml record.  */

static void
parse_xml_btrace_block (struct gdb_xml_parser *parser,
			const struct gdb_xml_element *element,
			void *user_data, VEC (gdb_xml_value_s) *attributes)
{
  VEC (btrace_block_s) **btrace;
  struct btrace_block *block;
  ULONGEST *begin, *end;

  btrace = user_data;
  block = VEC_safe_push (btrace_block_s, *btrace, NULL);

  begin = xml_find_attribute (attributes, "begin")->value;
  end = xml_find_attribute (attributes, "end")->value;

  block->begin = *begin;
  block->end = *end;
}

static const struct gdb_xml_attribute block_attributes[] = {
  { "begin", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
  { "end", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
  { NULL, GDB_XML_AF_NONE, NULL, NULL }
};

static const struct gdb_xml_attribute btrace_attributes[] = {
  { "version", GDB_XML_AF_NONE, NULL, NULL },
  { NULL, GDB_XML_AF_NONE, NULL, NULL }
};

static const struct gdb_xml_element btrace_children[] = {
  { "block", block_attributes, NULL,
    GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL, parse_xml_btrace_block, NULL },
  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};

static const struct gdb_xml_element btrace_elements[] = {
  { "btrace", btrace_attributes, btrace_children, GDB_XML_EF_NONE,
    check_xml_btrace_version, NULL },
  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};

#endif /* defined (HAVE_LIBEXPAT) */

/* See btrace.h.  */

VEC (btrace_block_s) *
parse_xml_btrace (const char *buffer)
{
  VEC (btrace_block_s) *btrace = NULL;
  struct cleanup *cleanup;
  int errcode;

#if defined (HAVE_LIBEXPAT)

  cleanup = make_cleanup (VEC_cleanup (btrace_block_s), &btrace);
  errcode = gdb_xml_parse_quick (_("btrace"), "btrace.dtd", btrace_elements,
				 buffer, &btrace);
  if (errcode != 0)
    error (_("Error parsing branch trace."));

  /* Keep parse results.  */
  discard_cleanups (cleanup);

#else  /* !defined (HAVE_LIBEXPAT) */

  error (_("Cannot process branch trace.  XML parsing is not supported."));

#endif  /* !defined (HAVE_LIBEXPAT) */

  return btrace;
}

/* See btrace.h.  */

const struct btrace_insn *
btrace_insn_get (const struct btrace_insn_iterator *it)
{
  const struct btrace_function *bfun;
  unsigned int index, end;

  index = it->index;
  bfun = it->function;

  /* The index is within the bounds of this function's instruction vector.  */
  end = VEC_length (btrace_insn_s, bfun->insn);
  gdb_assert (0 < end);
  gdb_assert (index < end);

  return VEC_index (btrace_insn_s, bfun->insn, index);
}

/* See btrace.h.  */

unsigned int
btrace_insn_number (const struct btrace_insn_iterator *it)
{
  const struct btrace_function *bfun;

  bfun = it->function;
  return bfun->insn_offset + it->index;
}

/* See btrace.h.  */

void
btrace_insn_begin (struct btrace_insn_iterator *it,
		   const struct btrace_thread_info *btinfo)
{
  const struct btrace_function *bfun;

  bfun = btinfo->begin;
  if (bfun == NULL)
    error (_("No trace."));

  it->function = bfun;
  it->index = 0;
}

/* See btrace.h.  */

void
btrace_insn_end (struct btrace_insn_iterator *it,
		 const struct btrace_thread_info *btinfo)
{
  const struct btrace_function *bfun;
  unsigned int length;

  bfun = btinfo->end;
  if (bfun == NULL)
    error (_("No trace."));

  /* The last instruction in the last function is the current instruction.
     We point to it - it is one past the end of the execution trace.  */
  length = VEC_length (btrace_insn_s, bfun->insn);

  it->function = bfun;
  it->index = length - 1;
}

/* See btrace.h.  */

unsigned int
btrace_insn_next (struct btrace_insn_iterator *it, unsigned int stride)
{
  const struct btrace_function *bfun;
  unsigned int index, steps;

  bfun = it->function;
  steps = 0;
  index = it->index;

  while (stride != 0)
    {
      unsigned int end, space, adv;

      end = VEC_length (btrace_insn_s, bfun->insn);

      gdb_assert (0 < end);
      gdb_assert (index < end);

      /* Compute the number of instructions remaining in this segment.  */
      space = end - index;

      /* Advance the iterator as far as possible within this segment.  */
      adv = min (space, stride);
      stride -= adv;
      index += adv;
      steps += adv;

      /* Move to the next function if we're at the end of this one.  */
      if (index == end)
	{
	  const struct btrace_function *next;

	  next = bfun->flow.next;
	  if (next == NULL)
	    {
	      /* We stepped past the last function.

		 Let's adjust the index to point to the last instruction in
		 the previous function.  */
	      index -= 1;
	      steps -= 1;
	      break;
	    }

	  /* We now point to the first instruction in the new function.  */
	  bfun = next;
	  index = 0;
	}

      /* We did make progress.  */
      gdb_assert (adv > 0);
    }

  /* Update the iterator.  */
  it->function = bfun;
  it->index = index;

  return steps;
}

/* See btrace.h.  */

unsigned int
btrace_insn_prev (struct btrace_insn_iterator *it, unsigned int stride)
{
  const struct btrace_function *bfun;
  unsigned int index, steps;

  bfun = it->function;
  steps = 0;
  index = it->index;

  while (stride != 0)
    {
      unsigned int adv;

      /* Move to the previous function if we're at the start of this one.  */
      if (index == 0)
	{
	  const struct btrace_function *prev;

	  prev = bfun->flow.prev;
	  if (prev == NULL)
	    break;

	  /* We point to one after the last instruction in the new function.  */
	  bfun = prev;
	  index = VEC_length (btrace_insn_s, bfun->insn);

	  /* There is at least one instruction in this function segment.  */
	  gdb_assert (index > 0);
	}

      /* Advance the iterator as far as possible within this segment.  */
      adv = min (index, stride);
      stride -= adv;
      index -= adv;
      steps += adv;

      /* We did make progress.  */
      gdb_assert (adv > 0);
    }

  /* Update the iterator.  */
  it->function = bfun;
  it->index = index;

  return steps;
}

/* See btrace.h.  */

int
btrace_insn_cmp (const struct btrace_insn_iterator *lhs,
		 const struct btrace_insn_iterator *rhs)
{
  unsigned int lnum, rnum;

  lnum = btrace_insn_number (lhs);
  rnum = btrace_insn_number (rhs);

  return (int) (lnum - rnum);
}

/* See btrace.h.  */

int
btrace_find_insn_by_number (struct btrace_insn_iterator *it,
			    const struct btrace_thread_info *btinfo,
			    unsigned int number)
{
  const struct btrace_function *bfun;
  unsigned int end;

  for (bfun = btinfo->end; bfun != NULL; bfun = bfun->flow.prev)
    if (bfun->insn_offset <= number)
      break;

  if (bfun == NULL)
    return 0;

  end = bfun->insn_offset + VEC_length (btrace_insn_s, bfun->insn);
  if (end <= number)
    return 0;

  it->function = bfun;
  it->index = number - bfun->insn_offset;

  return 1;
}

/* See btrace.h.  */

const struct btrace_function *
btrace_call_get (const struct btrace_call_iterator *it)
{
  return it->function;
}

/* See btrace.h.  */

unsigned int
btrace_call_number (const struct btrace_call_iterator *it)
{
  const struct btrace_thread_info *btinfo;
  const struct btrace_function *bfun;
  unsigned int insns;

  btinfo = it->btinfo;
  bfun = it->function;
  if (bfun != NULL)
    return bfun->number;

  /* For the end iterator, i.e. bfun == NULL, we return one more than the
     number of the last function.  */
  bfun = btinfo->end;
  insns = VEC_length (btrace_insn_s, bfun->insn);

  /* If the function contains only a single instruction (i.e. the current
     instruction), it will be skipped and its number is already the number
     we seek.  */
  if (insns == 1)
    return bfun->number;

  /* Otherwise, return one more than the number of the last function.  */
  return bfun->number + 1;
}

/* See btrace.h.  */

void
btrace_call_begin (struct btrace_call_iterator *it,
		   const struct btrace_thread_info *btinfo)
{
  const struct btrace_function *bfun;

  bfun = btinfo->begin;
  if (bfun == NULL)
    error (_("No trace."));

  it->btinfo = btinfo;
  it->function = bfun;
}

/* See btrace.h.  */

void
btrace_call_end (struct btrace_call_iterator *it,
		 const struct btrace_thread_info *btinfo)
{
  const struct btrace_function *bfun;

  bfun = btinfo->end;
  if (bfun == NULL)
    error (_("No trace."));

  it->btinfo = btinfo;
  it->function = NULL;
}

/* See btrace.h.  */

unsigned int
btrace_call_next (struct btrace_call_iterator *it, unsigned int stride)
{
  const struct btrace_function *bfun;
  unsigned int steps;

  bfun = it->function;
  steps = 0;
  while (bfun != NULL)
    {
      const struct btrace_function *next;
      unsigned int insns;

      next = bfun->flow.next;
      if (next == NULL)
	{
	  /* Ignore the last function if it only contains a single
	     (i.e. the current) instruction.  */
	  insns = VEC_length (btrace_insn_s, bfun->insn);
	  if (insns == 1)
	    steps -= 1;
	}

      if (stride == steps)
	break;

      bfun = next;
      steps += 1;
    }

  it->function = bfun;
  return steps;
}

/* See btrace.h.  */

unsigned int
btrace_call_prev (struct btrace_call_iterator *it, unsigned int stride)
{
  const struct btrace_thread_info *btinfo;
  const struct btrace_function *bfun;
  unsigned int steps;

  bfun = it->function;
  steps = 0;

  if (bfun == NULL)
    {
      unsigned int insns;

      btinfo = it->btinfo;
      bfun = btinfo->end;
      if (bfun == NULL)
	return 0;

      /* Ignore the last function if it only contains a single
	 (i.e. the current) instruction.  */
      insns = VEC_length (btrace_insn_s, bfun->insn);
      if (insns == 1)
	bfun = bfun->flow.prev;

      if (bfun == NULL)
	return 0;

      steps += 1;
    }

  while (steps < stride)
    {
      const struct btrace_function *prev;

      prev = bfun->flow.prev;
      if (prev == NULL)
	break;

      bfun = prev;
      steps += 1;
    }

  it->function = bfun;
  return steps;
}

/* See btrace.h.  */

int
btrace_call_cmp (const struct btrace_call_iterator *lhs,
		 const struct btrace_call_iterator *rhs)
{
  unsigned int lnum, rnum;

  lnum = btrace_call_number (lhs);
  rnum = btrace_call_number (rhs);

  return (int) (lnum - rnum);
}

/* See btrace.h.  */

int
btrace_find_call_by_number (struct btrace_call_iterator *it,
			    const struct btrace_thread_info *btinfo,
			    unsigned int number)
{
  const struct btrace_function *bfun;

  for (bfun = btinfo->end; bfun != NULL; bfun = bfun->flow.prev)
    {
      unsigned int bnum;

      bnum = bfun->number;
      if (number == bnum)
	{
	  it->btinfo = btinfo;
	  it->function = bfun;
	  return 1;
	}

      /* Functions are ordered and numbered consecutively.  We could bail out
	 earlier.  On the other hand, it is very unlikely that we search for
	 a nonexistent function.  */
  }

  return 0;
}

/* See btrace.h.  */

void
btrace_set_insn_history (struct btrace_thread_info *btinfo,
			 const struct btrace_insn_iterator *begin,
			 const struct btrace_insn_iterator *end)
{
  if (btinfo->insn_history == NULL)
    btinfo->insn_history = xzalloc (sizeof (*btinfo->insn_history));

  btinfo->insn_history->begin = *begin;
  btinfo->insn_history->end = *end;
}

/* See btrace.h.  */

void
btrace_set_call_history (struct btrace_thread_info *btinfo,
			 const struct btrace_call_iterator *begin,
			 const struct btrace_call_iterator *end)
{
  gdb_assert (begin->btinfo == end->btinfo);

  if (btinfo->call_history == NULL)
    btinfo->call_history = xzalloc (sizeof (*btinfo->call_history));

  btinfo->call_history->begin = *begin;
  btinfo->call_history->end = *end;
}

/* See btrace.h.  */

int
btrace_is_replaying (struct thread_info *tp)
{
  return tp->btrace.replay != NULL;
}

/* See btrace.h.  */

int
btrace_is_empty (struct thread_info *tp)
{
  struct btrace_insn_iterator begin, end;
  struct btrace_thread_info *btinfo;

  btinfo = &tp->btrace;

  if (btinfo->begin == NULL)
    return 1;

  btrace_insn_begin (&begin, btinfo);
  btrace_insn_end (&end, btinfo);

  return btrace_insn_cmp (&begin, &end) == 0;
}