aboutsummaryrefslogtreecommitdiffstats
path: root/tools/perf/util/probe-finder.c
blob: 5473f11a9bc8fc6bf3e35c203cc18517de57435a (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
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
/*
 * probe-finder.c : C expression to kprobe event converter
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
#include <dwarf-regs.h>

#include <linux/bitops.h>
#include "event.h"
#include "debug.h"
#include "util.h"
#include "symbol.h"
#include "probe-finder.h"

/* Kprobe tracer basic type is up to u64 */
#define MAX_BASIC_TYPE_BITS	64

/*
 * Compare the tail of two strings.
 * Return 0 if whole of either string is same as another's tail part.
 */
static int strtailcmp(const char *s1, const char *s2)
{
	int i1 = strlen(s1);
	int i2 = strlen(s2);
	while (--i1 >= 0 && --i2 >= 0) {
		if (s1[i1] != s2[i2])
			return s1[i1] - s2[i2];
	}
	return 0;
}

/* Line number list operations */

/* Add a line to line number list */
static int line_list__add_line(struct list_head *head, int line)
{
	struct line_node *ln;
	struct list_head *p;

	/* Reverse search, because new line will be the last one */
	list_for_each_entry_reverse(ln, head, list) {
		if (ln->line < line) {
			p = &ln->list;
			goto found;
		} else if (ln->line == line)	/* Already exist */
			return 1;
	}
	/* List is empty, or the smallest entry */
	p = head;
found:
	pr_debug("line list: add a line %u\n", line);
	ln = zalloc(sizeof(struct line_node));
	if (ln == NULL)
		return -ENOMEM;
	ln->line = line;
	INIT_LIST_HEAD(&ln->list);
	list_add(&ln->list, p);
	return 0;
}

/* Check if the line in line number list */
static int line_list__has_line(struct list_head *head, int line)
{
	struct line_node *ln;

	/* Reverse search, because new line will be the last one */
	list_for_each_entry(ln, head, list)
		if (ln->line == line)
			return 1;

	return 0;
}

/* Init line number list */
static void line_list__init(struct list_head *head)
{
	INIT_LIST_HEAD(head);
}

/* Free line number list */
static void line_list__free(struct list_head *head)
{
	struct line_node *ln;
	while (!list_empty(head)) {
		ln = list_first_entry(head, struct line_node, list);
		list_del(&ln->list);
		free(ln);
	}
}

/* Dwarf FL wrappers */
static char *debuginfo_path;	/* Currently dummy */

static const Dwfl_Callbacks offline_callbacks = {
	.find_debuginfo = dwfl_standard_find_debuginfo,
	.debuginfo_path = &debuginfo_path,

	.section_address = dwfl_offline_section_address,

	/* We use this table for core files too.  */
	.find_elf = dwfl_build_id_find_elf,
};

/* Get a Dwarf from offline image */
static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
{
	Dwfl_Module *mod;
	Dwarf *dbg = NULL;

	if (!dwflp)
		return NULL;

	*dwflp = dwfl_begin(&offline_callbacks);
	if (!*dwflp)
		return NULL;

	mod = dwfl_report_offline(*dwflp, "", "", fd);
	if (!mod)
		goto error;

	dbg = dwfl_module_getdwarf(mod, bias);
	if (!dbg) {
error:
		dwfl_end(*dwflp);
		*dwflp = NULL;
	}
	return dbg;
}

#if _ELFUTILS_PREREQ(0, 148)
/* This method is buggy if elfutils is older than 0.148 */
static int __linux_kernel_find_elf(Dwfl_Module *mod,
				   void **userdata,
				   const char *module_name,
				   Dwarf_Addr base,
				   char **file_name, Elf **elfp)
{
	int fd;
	const char *path = kernel_get_module_path(module_name);

	pr_debug2("Use file %s for %s\n", path, module_name);
	if (path) {
		fd = open(path, O_RDONLY);
		if (fd >= 0) {
			*file_name = strdup(path);
			return fd;
		}
	}
	/* If failed, try to call standard method */
	return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
					  file_name, elfp);
}

static const Dwfl_Callbacks kernel_callbacks = {
	.find_debuginfo = dwfl_standard_find_debuginfo,
	.debuginfo_path = &debuginfo_path,

	.find_elf = __linux_kernel_find_elf,
	.section_address = dwfl_linux_kernel_module_section_address,
};

/* Get a Dwarf from live kernel image */
static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
					  Dwarf_Addr *bias)
{
	Dwarf *dbg;

	if (!dwflp)
		return NULL;

	*dwflp = dwfl_begin(&kernel_callbacks);
	if (!*dwflp)
		return NULL;

	/* Load the kernel dwarves: Don't care the result here */
	dwfl_linux_kernel_report_kernel(*dwflp);
	dwfl_linux_kernel_report_modules(*dwflp);

	dbg = dwfl_addrdwarf(*dwflp, addr, bias);
	/* Here, check whether we could get a real dwarf */
	if (!dbg) {
		pr_debug("Failed to find kernel dwarf at %lx\n",
			 (unsigned long)addr);
		dwfl_end(*dwflp);
		*dwflp = NULL;
	}
	return dbg;
}
#else
/* With older elfutils, this just support kernel module... */
static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used, Dwfl **dwflp,
					  Dwarf_Addr *bias)
{
	int fd;
	const char *path = kernel_get_module_path("kernel");

	if (!path) {
		pr_err("Failed to find vmlinux path\n");
		return NULL;
	}

	pr_debug2("Use file %s for debuginfo\n", path);
	fd = open(path, O_RDONLY);
	if (fd < 0)
		return NULL;

	return dwfl_init_offline_dwarf(fd, dwflp, bias);
}
#endif

/* Dwarf wrappers */

/* Find the realpath of the target file. */
static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
{
	Dwarf_Files *files;
	size_t nfiles, i;
	const char *src = NULL;
	int ret;

	if (!fname)
		return NULL;

	ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
	if (ret != 0)
		return NULL;

	for (i = 0; i < nfiles; i++) {
		src = dwarf_filesrc(files, i, NULL, NULL);
		if (strtailcmp(src, fname) == 0)
			break;
	}
	if (i == nfiles)
		return NULL;
	return src;
}

/* Get DW_AT_comp_dir (should be NULL with older gcc) */
static const char *cu_get_comp_dir(Dwarf_Die *cu_die)
{
	Dwarf_Attribute attr;
	if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
		return NULL;
	return dwarf_formstring(&attr);
}

/* Compare diename and tname */
static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
{
	const char *name;
	name = dwarf_diename(dw_die);
	return name ? (strcmp(tname, name) == 0) : false;
}

/* Get callsite line number of inline-function instance */
static int die_get_call_lineno(Dwarf_Die *in_die)
{
	Dwarf_Attribute attr;
	Dwarf_Word ret;

	if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
		return -ENOENT;

	dwarf_formudata(&attr, &ret);
	return (int)ret;
}

/* Get type die */
static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
	Dwarf_Attribute attr;

	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
	    dwarf_formref_die(&attr, die_mem))
		return die_mem;
	else
		return NULL;
}

/* Get a type die, but skip qualifiers */
static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
	int tag;

	do {
		vr_die = die_get_type(vr_die, die_mem);
		if (!vr_die)
			break;
		tag = dwarf_tag(vr_die);
	} while (tag == DW_TAG_const_type ||
		 tag == DW_TAG_restrict_type ||
		 tag == DW_TAG_volatile_type ||
		 tag == DW_TAG_shared_type);

	return vr_die;
}

/* Get a type die, but skip qualifiers and typedef */
static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
	do {
		vr_die = __die_get_real_type(vr_die, die_mem);
	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);

	return vr_die;
}

static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
			      Dwarf_Word *result)
{
	Dwarf_Attribute attr;

	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
	    dwarf_formudata(&attr, result) != 0)
		return -ENOENT;

	return 0;
}

static bool die_is_signed_type(Dwarf_Die *tp_die)
{
	Dwarf_Word ret;

	if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
		return false;

	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
		ret == DW_ATE_signed_fixed);
}

static int die_get_byte_size(Dwarf_Die *tp_die)
{
	Dwarf_Word ret;

	if (die_get_attr_udata(tp_die, DW_AT_byte_size, &ret))
		return 0;

	return (int)ret;
}

static int die_get_bit_size(Dwarf_Die *tp_die)
{
	Dwarf_Word ret;

	if (die_get_attr_udata(tp_die, DW_AT_bit_size, &ret))
		return 0;

	return (int)ret;
}

static int die_get_bit_offset(Dwarf_Die *tp_die)
{
	Dwarf_Word ret;

	if (die_get_attr_udata(tp_die, DW_AT_bit_offset, &ret))
		return 0;

	return (int)ret;
}

/* Get data_member_location offset */
static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
{
	Dwarf_Attribute attr;
	Dwarf_Op *expr;
	size_t nexpr;
	int ret;

	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
		return -ENOENT;

	if (dwarf_formudata(&attr, offs) != 0) {
		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
		ret = dwarf_getlocation(&attr, &expr, &nexpr);
		if (ret < 0 || nexpr == 0)
			return -ENOENT;

		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
				 expr[0].atom, nexpr);
			return -ENOTSUP;
		}
		*offs = (Dwarf_Word)expr[0].number;
	}
	return 0;
}

/* Return values for die_find callbacks */
enum {
	DIE_FIND_CB_FOUND = 0,		/* End of Search */
	DIE_FIND_CB_CHILD = 1,		/* Search only children */
	DIE_FIND_CB_SIBLING = 2,	/* Search only siblings */
	DIE_FIND_CB_CONTINUE = 3,	/* Search children and siblings */
};

/* Search a child die */
static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
				 int (*callback)(Dwarf_Die *, void *),
				 void *data, Dwarf_Die *die_mem)
{
	Dwarf_Die child_die;
	int ret;

	ret = dwarf_child(rt_die, die_mem);
	if (ret != 0)
		return NULL;

	do {
		ret = callback(die_mem, data);
		if (ret == DIE_FIND_CB_FOUND)
			return die_mem;

		if ((ret & DIE_FIND_CB_CHILD) &&
		    die_find_child(die_mem, callback, data, &child_die)) {
			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
			return die_mem;
		}
	} while ((ret & DIE_FIND_CB_SIBLING) &&
		 dwarf_siblingof(die_mem, die_mem) == 0);

	return NULL;
}

struct __addr_die_search_param {
	Dwarf_Addr	addr;
	Dwarf_Die	*die_mem;
};

static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
{
	struct __addr_die_search_param *ad = data;

	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
	    dwarf_haspc(fn_die, ad->addr)) {
		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
		return DWARF_CB_ABORT;
	}
	return DWARF_CB_OK;
}

/* Search a real subprogram including this line, */
static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
					   Dwarf_Die *die_mem)
{
	struct __addr_die_search_param ad;
	ad.addr = addr;
	ad.die_mem = die_mem;
	/* dwarf_getscopes can't find subprogram. */
	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
		return NULL;
	else
		return die_mem;
}

/* die_find callback for inline function search */
static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
{
	Dwarf_Addr *addr = data;

	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
	    dwarf_haspc(die_mem, *addr))
		return DIE_FIND_CB_FOUND;

	return DIE_FIND_CB_CONTINUE;
}

/* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
				      Dwarf_Die *die_mem)
{
	return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
}

/* Walker on lines (Note: line number will not be sorted) */
typedef int (* line_walk_handler_t) (const char *fname, int lineno,
				     Dwarf_Addr addr, void *data);

struct __line_walk_param {
	const char *fname;
	line_walk_handler_t handler;
	void *data;
	int retval;
};

static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
{
	struct __line_walk_param *lw = data;
	Dwarf_Addr addr;
	int lineno;

	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
		lineno = die_get_call_lineno(in_die);
		if (lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
			lw->retval = lw->handler(lw->fname, lineno, addr,
						 lw->data);
			if (lw->retval != 0)
				return DIE_FIND_CB_FOUND;
		}
	}
	return DIE_FIND_CB_SIBLING;
}

/* Walk on lines of blocks included in given DIE */
static int __die_walk_funclines(Dwarf_Die *sp_die,
				line_walk_handler_t handler, void *data)
{
	struct __line_walk_param lw = {
		.handler = handler,
		.data = data,
		.retval = 0,
	};
	Dwarf_Die die_mem;
	Dwarf_Addr addr;
	int lineno;

	/* Handle function declaration line */
	lw.fname = dwarf_decl_file(sp_die);
	if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
	    dwarf_entrypc(sp_die, &addr) == 0) {
		lw.retval = handler(lw.fname, lineno, addr, data);
		if (lw.retval != 0)
			goto done;
	}
	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
done:
	return lw.retval;
}

static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
{
	struct __line_walk_param *lw = data;

	lw->retval = __die_walk_funclines(sp_die, lw->handler, lw->data);
	if (lw->retval != 0)
		return DWARF_CB_ABORT;

	return DWARF_CB_OK;
}

/*
 * Walk on lines inside given PDIE. If the PDIE is subprogram, walk only on
 * the lines inside the subprogram, otherwise PDIE must be a CU DIE.
 */
static int die_walk_lines(Dwarf_Die *pdie, line_walk_handler_t handler,
			  void *data)
{
	Dwarf_Lines *lines;
	Dwarf_Line *line;
	Dwarf_Addr addr;
	const char *fname;
	int lineno, ret = 0;
	Dwarf_Die die_mem, *cu_die;
	size_t nlines, i;

	/* Get the CU die */
	if (dwarf_tag(pdie) == DW_TAG_subprogram)
		cu_die = dwarf_diecu(pdie, &die_mem, NULL, NULL);
	else
		cu_die = pdie;
	if (!cu_die) {
		pr_debug2("Failed to get CU from subprogram\n");
		return -EINVAL;
	}

	/* Get lines list in the CU */
	if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
		pr_debug2("Failed to get source lines on this CU.\n");
		return -ENOENT;
	}
	pr_debug2("Get %zd lines from this CU\n", nlines);

	/* Walk on the lines on lines list */
	for (i = 0; i < nlines; i++) {
		line = dwarf_onesrcline(lines, i);
		if (line == NULL ||
		    dwarf_lineno(line, &lineno) != 0 ||
		    dwarf_lineaddr(line, &addr) != 0) {
			pr_debug2("Failed to get line info. "
				  "Possible error in debuginfo.\n");
			continue;
		}
		/* Filter lines based on address */
		if (pdie != cu_die)
			/*
			 * Address filtering
			 * The line is included in given function, and
			 * no inline block includes it.
			 */
			if (!dwarf_haspc(pdie, addr) ||
			    die_find_inlinefunc(pdie, addr, &die_mem))
				continue;
		/* Get source line */
		fname = dwarf_linesrc(line, NULL, NULL);

		ret = handler(fname, lineno, addr, data);
		if (ret != 0)
			return ret;
	}

	/*
	 * Dwarf lines doesn't include function declarations and inlined
	 * subroutines. We have to check functions list or given function.
	 */
	if (pdie != cu_die)
		ret = __die_walk_funclines(pdie, handler, data);
	else {
		struct __line_walk_param param = {
			.handler = handler,
			.data = data,
			.retval = 0,
		};
		dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
		ret = param.retval;
	}

	return ret;
}

struct __find_variable_param {
	const char *name;
	Dwarf_Addr addr;
};

static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
	struct __find_variable_param *fvp = data;
	int tag;

	tag = dwarf_tag(die_mem);
	if ((tag == DW_TAG_formal_parameter ||
	     tag == DW_TAG_variable) &&
	    die_compare_name(die_mem, fvp->name))
		return DIE_FIND_CB_FOUND;

	if (dwarf_haspc(die_mem, fvp->addr))
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

/* Find a variable called 'name' at given address */
static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
				       Dwarf_Addr addr, Dwarf_Die *die_mem)
{
	struct __find_variable_param fvp = { .name = name, .addr = addr};

	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
			      die_mem);
}

static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
{
	const char *name = data;

	if ((dwarf_tag(die_mem) == DW_TAG_member) &&
	    die_compare_name(die_mem, name))
		return DIE_FIND_CB_FOUND;

	return DIE_FIND_CB_SIBLING;
}

/* Find a member called 'name' */
static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
				  Dwarf_Die *die_mem)
{
	return die_find_child(st_die, __die_find_member_cb, (void *)name,
			      die_mem);
}

/* Get the name of given variable DIE */
static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
{
	Dwarf_Die type;
	int tag, ret, ret2;
	const char *tmp = "";

	if (__die_get_real_type(vr_die, &type) == NULL)
		return -ENOENT;

	tag = dwarf_tag(&type);
	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
		tmp = "*";
	else if (tag == DW_TAG_subroutine_type) {
		/* Function pointer */
		ret = snprintf(buf, len, "(function_type)");
		return (ret >= len) ? -E2BIG : ret;
	} else {
		if (!dwarf_diename(&type))
			return -ENOENT;
		if (tag == DW_TAG_union_type)
			tmp = "union ";
		else if (tag == DW_TAG_structure_type)
			tmp = "struct ";
		/* Write a base name */
		ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
		return (ret >= len) ? -E2BIG : ret;
	}
	ret = die_get_typename(&type, buf, len);
	if (ret > 0) {
		ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
	}
	return ret;
}

/* Get the name and type of given variable DIE, stored as "type\tname" */
static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
{
	int ret, ret2;

	ret = die_get_typename(vr_die, buf, len);
	if (ret < 0) {
		pr_debug("Failed to get type, make it unknown.\n");
		ret = snprintf(buf, len, "(unknown_type)");
	}
	if (ret > 0) {
		ret2 = snprintf(buf + ret, len - ret, "\t%s",
				dwarf_diename(vr_die));
		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
	}
	return ret;
}

/*
 * Probe finder related functions
 */

static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
{
	struct probe_trace_arg_ref *ref;
	ref = zalloc(sizeof(struct probe_trace_arg_ref));
	if (ref != NULL)
		ref->offset = offs;
	return ref;
}

/*
 * Convert a location into trace_arg.
 * If tvar == NULL, this just checks variable can be converted.
 */
static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
				     Dwarf_Op *fb_ops,
				     struct probe_trace_arg *tvar)
{
	Dwarf_Attribute attr;
	Dwarf_Op *op;
	size_t nops;
	unsigned int regn;
	Dwarf_Word offs = 0;
	bool ref = false;
	const char *regs;
	int ret;

	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
		goto static_var;

	/* TODO: handle more than 1 exprs */
	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
	    dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
	    nops == 0) {
		/* TODO: Support const_value */
		return -ENOENT;
	}

	if (op->atom == DW_OP_addr) {
static_var:
		if (!tvar)
			return 0;
		/* Static variables on memory (not stack), make @varname */
		ret = strlen(dwarf_diename(vr_die));
		tvar->value = zalloc(ret + 2);
		if (tvar->value == NULL)
			return -ENOMEM;
		snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
		tvar->ref = alloc_trace_arg_ref((long)offs);
		if (tvar->ref == NULL)
			return -ENOMEM;
		return 0;
	}

	/* If this is based on frame buffer, set the offset */
	if (op->atom == DW_OP_fbreg) {
		if (fb_ops == NULL)
			return -ENOTSUP;
		ref = true;
		offs = op->number;
		op = &fb_ops[0];
	}

	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
		regn = op->atom - DW_OP_breg0;
		offs += op->number;
		ref = true;
	} else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
		regn = op->atom - DW_OP_reg0;
	} else if (op->atom == DW_OP_bregx) {
		regn = op->number;
		offs += op->number2;
		ref = true;
	} else if (op->atom == DW_OP_regx) {
		regn = op->number;
	} else {
		pr_debug("DW_OP %x is not supported.\n", op->atom);
		return -ENOTSUP;
	}

	if (!tvar)
		return 0;

	regs = get_arch_regstr(regn);
	if (!regs) {
		/* This should be a bug in DWARF or this tool */
		pr_warning("Mapping for the register number %u "
			   "missing on this architecture.\n", regn);
		return -ERANGE;
	}

	tvar->value = strdup(regs);
	if (tvar->value == NULL)
		return -ENOMEM;

	if (ref) {
		tvar->ref = alloc_trace_arg_ref((long)offs);
		if (tvar->ref == NULL)
			return -ENOMEM;
	}
	return 0;
}

#define BYTES_TO_BITS(nb)	((nb) * BITS_PER_LONG / sizeof(long))

static int convert_variable_type(Dwarf_Die *vr_die,
				 struct probe_trace_arg *tvar,
				 const char *cast)
{
	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
	Dwarf_Die type;
	char buf[16];
	int ret;

	/* TODO: check all types */
	if (cast && strcmp(cast, "string") != 0) {
		/* Non string type is OK */
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

	if (die_get_bit_size(vr_die) != 0) {
		/* This is a bitfield */
		ret = snprintf(buf, 16, "b%d@%d/%zd", die_get_bit_size(vr_die),
				die_get_bit_offset(vr_die),
				BYTES_TO_BITS(die_get_byte_size(vr_die)));
		goto formatted;
	}

	if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get a type information of %s.\n",
			   dwarf_diename(vr_die));
		return -ENOENT;
	}

	pr_debug("%s type is %s.\n",
		 dwarf_diename(vr_die), dwarf_diename(&type));

	if (cast && strcmp(cast, "string") == 0) {	/* String type */
		ret = dwarf_tag(&type);
		if (ret != DW_TAG_pointer_type &&
		    ret != DW_TAG_array_type) {
			pr_warning("Failed to cast into string: "
				   "%s(%s) is not a pointer nor array.\n",
				   dwarf_diename(vr_die), dwarf_diename(&type));
			return -EINVAL;
		}
		if (ret == DW_TAG_pointer_type) {
			if (die_get_real_type(&type, &type) == NULL) {
				pr_warning("Failed to get a type"
					   " information.\n");
				return -ENOENT;
			}
			while (*ref_ptr)
				ref_ptr = &(*ref_ptr)->next;
			/* Add new reference with offset +0 */
			*ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
			if (*ref_ptr == NULL) {
				pr_warning("Out of memory error\n");
				return -ENOMEM;
			}
		}
		if (!die_compare_name(&type, "char") &&
		    !die_compare_name(&type, "unsigned char")) {
			pr_warning("Failed to cast into string: "
				   "%s is not (unsigned) char *.\n",
				   dwarf_diename(vr_die));
			return -EINVAL;
		}
		tvar->type = strdup(cast);
		return (tvar->type == NULL) ? -ENOMEM : 0;
	}

	ret = BYTES_TO_BITS(die_get_byte_size(&type));
	if (!ret)
		/* No size ... try to use default type */
		return 0;

	/* Check the bitwidth */
	if (ret > MAX_BASIC_TYPE_BITS) {
		pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
			dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
		ret = MAX_BASIC_TYPE_BITS;
	}
	ret = snprintf(buf, 16, "%c%d",
		       die_is_signed_type(&type) ? 's' : 'u', ret);

formatted:
	if (ret < 0 || ret >= 16) {
		if (ret >= 16)
			ret = -E2BIG;
		pr_warning("Failed to convert variable type: %s\n",
			   strerror(-ret));
		return ret;
	}
	tvar->type = strdup(buf);
	if (tvar->type == NULL)
		return -ENOMEM;
	return 0;
}

static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
				    struct perf_probe_arg_field *field,
				    struct probe_trace_arg_ref **ref_ptr,
				    Dwarf_Die *die_mem)
{
	struct probe_trace_arg_ref *ref = *ref_ptr;
	Dwarf_Die type;
	Dwarf_Word offs;
	int ret, tag;

	pr_debug("converting %s in %s\n", field->name, varname);
	if (die_get_real_type(vr_die, &type) == NULL) {
		pr_warning("Failed to get the type of %s.\n", varname);
		return -ENOENT;
	}
	pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
	tag = dwarf_tag(&type);

	if (field->name[0] == '[' &&
	    (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
		if (field->next)
			/* Save original type for next field */
			memcpy(die_mem, &type, sizeof(*die_mem));
		/* Get the type of this array */
		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get the type of %s.\n", varname);
			return -ENOENT;
		}
		pr_debug2("Array real type: (%x)\n",
			 (unsigned)dwarf_dieoffset(&type));
		if (tag == DW_TAG_pointer_type) {
			ref = zalloc(sizeof(struct probe_trace_arg_ref));
			if (ref == NULL)
				return -ENOMEM;
			if (*ref_ptr)
				(*ref_ptr)->next = ref;
			else
				*ref_ptr = ref;
		}
		ref->offset += die_get_byte_size(&type) * field->index;
		if (!field->next)
			/* Save vr_die for converting types */
			memcpy(die_mem, vr_die, sizeof(*die_mem));
		goto next;
	} else if (tag == DW_TAG_pointer_type) {
		/* Check the pointer and dereference */
		if (!field->ref) {
			pr_err("Semantic error: %s must be referred by '->'\n",
			       field->name);
			return -EINVAL;
		}
		/* Get the type pointed by this pointer */
		if (die_get_real_type(&type, &type) == NULL) {
			pr_warning("Failed to get the type of %s.\n", varname);
			return -ENOENT;
		}
		/* Verify it is a data structure  */
		if (dwarf_tag(&type) != DW_TAG_structure_type) {
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}

		ref = zalloc(sizeof(struct probe_trace_arg_ref));
		if (ref == NULL)
			return -ENOMEM;
		if (*ref_ptr)
			(*ref_ptr)->next = ref;
		else
			*ref_ptr = ref;
	} else {
		/* Verify it is a data structure  */
		if (tag != DW_TAG_structure_type) {
			pr_warning("%s is not a data structure.\n", varname);
			return -EINVAL;
		}
		if (field->name[0] == '[') {
			pr_err("Semantic error: %s is not a pointor"
			       " nor array.\n", varname);
			return -EINVAL;
		}
		if (field->ref) {
			pr_err("Semantic error: %s must be referred by '.'\n",
			       field->name);
			return -EINVAL;
		}
		if (!ref) {
			pr_warning("Structure on a register is not "
				   "supported yet.\n");
			return -ENOTSUP;
		}
	}

	if (die_find_member(&type, field->name, die_mem) == NULL) {
		pr_warning("%s(tyep:%s) has no member %s.\n", varname,
			   dwarf_diename(&type), field->name);
		return -EINVAL;
	}

	/* Get the offset of the field */
	ret = die_get_data_member_location(die_mem, &offs);
	if (ret < 0) {
		pr_warning("Failed to get the offset of %s.\n", field->name);
		return ret;
	}
	ref->offset += (long)offs;

next:
	/* Converting next field */
	if (field->next)
		return convert_variable_fields(die_mem, field->name,
					field->next, &ref, die_mem);
	else
		return 0;
}

/* Show a variables in kprobe event format */
static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
{
	Dwarf_Die die_mem;
	int ret;

	pr_debug("Converting variable %s into trace event.\n",
		 dwarf_diename(vr_die));

	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
					pf->tvar);
	if (ret == -ENOENT)
		pr_err("Failed to find the location of %s at this address.\n"
		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
	else if (ret == -ENOTSUP)
		pr_err("Sorry, we don't support this variable location yet.\n");
	else if (pf->pvar->field) {
		ret = convert_variable_fields(vr_die, pf->pvar->var,
					      pf->pvar->field, &pf->tvar->ref,
					      &die_mem);
		vr_die = &die_mem;
	}
	if (ret == 0)
		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
	/* *expr will be cached in libdw. Don't free it. */
	return ret;
}

/* Find a variable in a subprogram die */
static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	Dwarf_Die vr_die, *scopes;
	char buf[32], *ptr;
	int ret, nscopes;

	if (!is_c_varname(pf->pvar->var)) {
		/* Copy raw parameters */
		pf->tvar->value = strdup(pf->pvar->var);
		if (pf->tvar->value == NULL)
			return -ENOMEM;
		if (pf->pvar->type) {
			pf->tvar->type = strdup(pf->pvar->type);
			if (pf->tvar->type == NULL)
				return -ENOMEM;
		}
		if (pf->pvar->name) {
			pf->tvar->name = strdup(pf->pvar->name);
			if (pf->tvar->name == NULL)
				return -ENOMEM;
		} else
			pf->tvar->name = NULL;
		return 0;
	}

	if (pf->pvar->name)
		pf->tvar->name = strdup(pf->pvar->name);
	else {
		ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
		if (ret < 0)
			return ret;
		ptr = strchr(buf, ':');	/* Change type separator to _ */
		if (ptr)
			*ptr = '_';
		pf->tvar->name = strdup(buf);
	}
	if (pf->tvar->name == NULL)
		return -ENOMEM;

	pr_debug("Searching '%s' variable in context.\n",
		 pf->pvar->var);
	/* Search child die for local variables and parameters. */
	if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
		ret = convert_variable(&vr_die, pf);
	else {
		/* Search upper class */
		nscopes = dwarf_getscopes_die(sp_die, &scopes);
		while (nscopes-- > 1) {
			pr_debug("Searching variables in %s\n",
				 dwarf_diename(&scopes[nscopes]));
			/* We should check this scope, so give dummy address */
			if (die_find_variable_at(&scopes[nscopes],
						 pf->pvar->var, 0,
						 &vr_die)) {
				ret = convert_variable(&vr_die, pf);
				goto found;
			}
		}
		if (scopes)
			free(scopes);
		ret = -ENOENT;
	}
found:
	if (ret < 0)
		pr_warning("Failed to find '%s' in this function.\n",
			   pf->pvar->var);
	return ret;
}

/* Convert subprogram DIE to trace point */
static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
				  bool retprobe, struct probe_trace_point *tp)
{
	Dwarf_Addr eaddr;
	const char *name;

	/* Copy the name of probe point */
	name = dwarf_diename(sp_die);
	if (name) {
		if (dwarf_entrypc(sp_die, &eaddr) != 0) {
			pr_warning("Failed to get entry address of %s\n",
				   dwarf_diename(sp_die));
			return -ENOENT;
		}
		tp->symbol = strdup(name);
		if (tp->symbol == NULL)
			return -ENOMEM;
		tp->offset = (unsigned long)(paddr - eaddr);
	} else
		/* This function has no name. */
		tp->offset = (unsigned long)paddr;

	/* Return probe must be on the head of a subprogram */
	if (retprobe) {
		if (eaddr != paddr) {
			pr_warning("Return probe must be on the head of"
				   " a real function.\n");
			return -EINVAL;
		}
		tp->retprobe = true;
	}

	return 0;
}

/* Call probe_finder callback with real subprogram DIE */
static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	Dwarf_Die die_mem;
	Dwarf_Attribute fb_attr;
	size_t nops;
	int ret;

	/* If no real subprogram, find a real one */
	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
		sp_die = die_find_real_subprogram(&pf->cu_die,
						  pf->addr, &die_mem);
		if (!sp_die) {
			pr_warning("Failed to find probe point in any "
				   "functions.\n");
			return -ENOENT;
		}
	}

	/* Get the frame base attribute/ops */
	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
	ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
	if (ret <= 0 || nops == 0) {
		pf->fb_ops = NULL;
#if _ELFUTILS_PREREQ(0, 142)
	} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
		   pf->cfi != NULL) {
		Dwarf_Frame *frame;
		if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
		    dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
			pr_warning("Failed to get call frame on 0x%jx\n",
				   (uintmax_t)pf->addr);
			return -ENOENT;
		}
#endif
	}

	/* Call finder's callback handler */
	ret = pf->callback(sp_die, pf);

	/* *pf->fb_ops will be cached in libdw. Don't free it. */
	pf->fb_ops = NULL;

	return ret;
}

static int probe_point_line_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
{
	struct probe_finder *pf = data;
	int ret;

	if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
		return 0;

	pf->addr = addr;
	ret = call_probe_finder(NULL, pf);

	/* Continue if no error, because the line will be in inline function */
	return ret < 0 ? ret : 0;
}

/* Find probe point from its line number */
static int find_probe_point_by_line(struct probe_finder *pf)
{
	return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
}

/* Find lines which match lazy pattern */
static int find_lazy_match_lines(struct list_head *head,
				 const char *fname, const char *pat)
{
	FILE *fp;
	char *line = NULL;
	size_t line_len;
	ssize_t len;
	int count = 0, linenum = 1;

	fp = fopen(fname, "r");
	if (!fp) {
		pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
		return -errno;
	}

	while ((len = getline(&line, &line_len, fp)) > 0) {

		if (line[len - 1] == '\n')
			line[len - 1] = '\0';

		if (strlazymatch(line, pat)) {
			line_list__add_line(head, linenum);
			count++;
		}
		linenum++;
	}

	if (ferror(fp))
		count = -errno;
	free(line);
	fclose(fp);

	if (count == 0)
		pr_debug("No matched lines found in %s.\n", fname);
	return count;
}

static int probe_point_lazy_walker(const char *fname, int lineno,
				   Dwarf_Addr addr, void *data)
{
	struct probe_finder *pf = data;
	int ret;

	if (!line_list__has_line(&pf->lcache, lineno) ||
	    strtailcmp(fname, pf->fname) != 0)
		return 0;

	pr_debug("Probe line found: line:%d addr:0x%llx\n",
		 lineno, (unsigned long long)addr);
	pf->addr = addr;
	ret = call_probe_finder(NULL, pf);

	/*
	 * Continue if no error, because the lazy pattern will match
	 * to other lines
	 */
	return ret < 0 ? ret : 0;
}

/* Find probe points from lazy pattern  */
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	int ret = 0;

	if (list_empty(&pf->lcache)) {
		/* Matching lazy line pattern */
		ret = find_lazy_match_lines(&pf->lcache, pf->fname,
					    pf->pev->point.lazy_line);
		if (ret <= 0)
			return ret;
	}

	return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
}

/* Callback parameter with return value */
struct dwarf_callback_param {
	void *data;
	int retval;
};

static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;
	Dwarf_Addr addr;

	if (pp->lazy_line)
		param->retval = find_probe_point_lazy(in_die, pf);
	else {
		/* Get probe address */
		if (dwarf_entrypc(in_die, &addr) != 0) {
			pr_warning("Failed to get entry address of %s.\n",
				   dwarf_diename(in_die));
			param->retval = -ENOENT;
			return DWARF_CB_ABORT;
		}
		pf->addr = addr;
		pf->addr += pp->offset;
		pr_debug("found inline addr: 0x%jx\n",
			 (uintmax_t)pf->addr);

		param->retval = call_probe_finder(in_die, pf);
		if (param->retval < 0)
			return DWARF_CB_ABORT;
	}

	return DWARF_CB_OK;
}

/* Search function from function name */
static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct probe_finder *pf = param->data;
	struct perf_probe_point *pp = &pf->pev->point;

	/* Check tag and diename */
	if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
	    !die_compare_name(sp_die, pp->function))
		return DWARF_CB_OK;

	/* Check declared file */
	if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

	pf->fname = dwarf_decl_file(sp_die);
	if (pp->line) { /* Function relative line */
		dwarf_decl_line(sp_die, &pf->lno);
		pf->lno += pp->line;
		param->retval = find_probe_point_by_line(pf);
	} else if (!dwarf_func_inline(sp_die)) {
		/* Real function */
		if (pp->lazy_line)
			param->retval = find_probe_point_lazy(sp_die, pf);
		else {
			if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
				pr_warning("Failed to get entry address of "
					   "%s.\n", dwarf_diename(sp_die));
				param->retval = -ENOENT;
				return DWARF_CB_ABORT;
			}
			pf->addr += pp->offset;
			/* TODO: Check the address in this function */
			param->retval = call_probe_finder(sp_die, pf);
		}
	} else {
		struct dwarf_callback_param _param = {.data = (void *)pf,
						      .retval = 0};
		/* Inlined function: search instances */
		dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
					    &_param);
		param->retval = _param.retval;
	}

	return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
}

static int find_probe_point_by_func(struct probe_finder *pf)
{
	struct dwarf_callback_param _param = {.data = (void *)pf,
					      .retval = 0};
	dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
	return _param.retval;
}

/* Find probe points from debuginfo */
static int find_probes(int fd, struct probe_finder *pf)
{
	struct perf_probe_point *pp = &pf->pev->point;
	Dwarf_Off off, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg = NULL;
	Dwfl *dwfl;
	Dwarf_Addr bias;	/* Currently ignored */
	int ret = 0;

	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
	if (!dbg) {
		pr_warning("No debug information found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		close(fd);	/* Without dwfl_end(), fd isn't closed. */
		return -EBADF;
	}

#if _ELFUTILS_PREREQ(0, 142)
	/* Get the call frame information from this dwarf */
	pf->cfi = dwarf_getcfi(dbg);
#endif

	off = 0;
	line_list__init(&pf->lcache);
	/* Loop on CUs (Compilation Unit) */
	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
		/* Get the DIE(Debugging Information Entry) of this CU */
		diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
		if (!diep)
			continue;

		/* Check if target file is included. */
		if (pp->file)
			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
		else
			pf->fname = NULL;

		if (!pp->file || pf->fname) {
			if (pp->function)
				ret = find_probe_point_by_func(pf);
			else if (pp->lazy_line)
				ret = find_probe_point_lazy(NULL, pf);
			else {
				pf->lno = pp->line;
				ret = find_probe_point_by_line(pf);
			}
			if (ret < 0)
				break;
		}
		off = noff;
	}
	line_list__free(&pf->lcache);
	if (dwfl)
		dwfl_end(dwfl);

	return ret;
}

/* Add a found probe point into trace event list */
static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	struct trace_event_finder *tf =
			container_of(pf, struct trace_event_finder, pf);
	struct probe_trace_event *tev;
	int ret, i;

	/* Check number of tevs */
	if (tf->ntevs == tf->max_tevs) {
		pr_warning("Too many( > %d) probe point found.\n",
			   tf->max_tevs);
		return -ERANGE;
	}
	tev = &tf->tevs[tf->ntevs++];

	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
				     &tev->point);
	if (ret < 0)
		return ret;

	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
		 tev->point.offset);

	/* Find each argument */
	tev->nargs = pf->pev->nargs;
	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
	if (tev->args == NULL)
		return -ENOMEM;
	for (i = 0; i < pf->pev->nargs; i++) {
		pf->pvar = &pf->pev->args[i];
		pf->tvar = &tev->args[i];
		ret = find_variable(sp_die, pf);
		if (ret != 0)
			return ret;
	}

	return 0;
}

/* Find probe_trace_events specified by perf_probe_event from debuginfo */
int find_probe_trace_events(int fd, struct perf_probe_event *pev,
			    struct probe_trace_event **tevs, int max_tevs)
{
	struct trace_event_finder tf = {
			.pf = {.pev = pev, .callback = add_probe_trace_event},
			.max_tevs = max_tevs};
	int ret;

	/* Allocate result tevs array */
	*tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
	if (*tevs == NULL)
		return -ENOMEM;

	tf.tevs = *tevs;
	tf.ntevs = 0;

	ret = find_probes(fd, &tf.pf);
	if (ret < 0) {
		free(*tevs);
		*tevs = NULL;
		return ret;
	}

	return (ret < 0) ? ret : tf.ntevs;
}

#define MAX_VAR_LEN 64

/* Collect available variables in this scope */
static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
{
	struct available_var_finder *af = data;
	struct variable_list *vl;
	char buf[MAX_VAR_LEN];
	int tag, ret;

	vl = &af->vls[af->nvls - 1];

	tag = dwarf_tag(die_mem);
	if (tag == DW_TAG_formal_parameter ||
	    tag == DW_TAG_variable) {
		ret = convert_variable_location(die_mem, af->pf.addr,
						af->pf.fb_ops, NULL);
		if (ret == 0) {
			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
			pr_debug2("Add new var: %s\n", buf);
			if (ret > 0)
				strlist__add(vl->vars, buf);
		}
	}

	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
		return DIE_FIND_CB_CONTINUE;
	else
		return DIE_FIND_CB_SIBLING;
}

/* Add a found vars into available variables list */
static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
{
	struct available_var_finder *af =
			container_of(pf, struct available_var_finder, pf);
	struct variable_list *vl;
	Dwarf_Die die_mem, *scopes = NULL;
	int ret, nscopes;

	/* Check number of tevs */
	if (af->nvls == af->max_vls) {
		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
		return -ERANGE;
	}
	vl = &af->vls[af->nvls++];

	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
				     &vl->point);
	if (ret < 0)
		return ret;

	pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
		 vl->point.offset);

	/* Find local variables */
	vl->vars = strlist__new(true, NULL);
	if (vl->vars == NULL)
		return -ENOMEM;
	af->child = true;
	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);

	/* Find external variables */
	if (!af->externs)
		goto out;
	/* Don't need to search child DIE for externs. */
	af->child = false;
	nscopes = dwarf_getscopes_die(sp_die, &scopes);
	while (nscopes-- > 1)
		die_find_child(&scopes[nscopes], collect_variables_cb,
			       (void *)af, &die_mem);
	if (scopes)
		free(scopes);

out:
	if (strlist__empty(vl->vars)) {
		strlist__delete(vl->vars);
		vl->vars = NULL;
	}

	return ret;
}

/* Find available variables at given probe point */
int find_available_vars_at(int fd, struct perf_probe_event *pev,
			   struct variable_list **vls, int max_vls,
			   bool externs)
{
	struct available_var_finder af = {
			.pf = {.pev = pev, .callback = add_available_vars},
			.max_vls = max_vls, .externs = externs};
	int ret;

	/* Allocate result vls array */
	*vls = zalloc(sizeof(struct variable_list) * max_vls);
	if (*vls == NULL)
		return -ENOMEM;

	af.vls = *vls;
	af.nvls = 0;

	ret = find_probes(fd, &af.pf);
	if (ret < 0) {
		/* Free vlist for error */
		while (af.nvls--) {
			if (af.vls[af.nvls].point.symbol)
				free(af.vls[af.nvls].point.symbol);
			if (af.vls[af.nvls].vars)
				strlist__delete(af.vls[af.nvls].vars);
		}
		free(af.vls);
		*vls = NULL;
		return ret;
	}

	return (ret < 0) ? ret : af.nvls;
}

/* Reverse search */
int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
{
	Dwarf_Die cudie, spdie, indie;
	Dwarf *dbg = NULL;
	Dwfl *dwfl = NULL;
	Dwarf_Line *line;
	Dwarf_Addr laddr, eaddr, bias = 0;
	const char *tmp;
	int lineno, ret = 0;
	bool found = false;

	/* Open the live linux kernel */
	dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
	if (!dbg) {
		pr_warning("No debug information found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		ret = -EINVAL;
		goto end;
	}

	/* Adjust address with bias */
	addr += bias;
	/* Find cu die */
	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
		pr_warning("Failed to find debug information for address %lx\n",
			   addr);
		ret = -EINVAL;
		goto end;
	}

	/* Find a corresponding line */
	line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
	if (line) {
		if (dwarf_lineaddr(line, &laddr) == 0 &&
		    (Dwarf_Addr)addr == laddr &&
		    dwarf_lineno(line, &lineno) == 0) {
			tmp = dwarf_linesrc(line, NULL, NULL);
			if (tmp) {
				ppt->line = lineno;
				ppt->file = strdup(tmp);
				if (ppt->file == NULL) {
					ret = -ENOMEM;
					goto end;
				}
				found = true;
			}
		}
	}

	/* Find a corresponding function */
	if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
		tmp = dwarf_diename(&spdie);
		if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
			goto end;

		if (ppt->line) {
			if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
						&indie)) {
				/* addr in an inline function */
				tmp = dwarf_diename(&indie);
				if (!tmp)
					goto end;
				ret = dwarf_decl_line(&indie, &lineno);
			} else {
				if (eaddr == addr) {	/* Function entry */
					lineno = ppt->line;
					ret = 0;
				} else
					ret = dwarf_decl_line(&spdie, &lineno);
			}
			if (ret == 0) {
				/* Make a relative line number */
				ppt->line -= lineno;
				goto found;
			}
		}
		/* We don't have a line number, let's use offset */
		ppt->offset = addr - (unsigned long)eaddr;
found:
		ppt->function = strdup(tmp);
		if (ppt->function == NULL) {
			ret = -ENOMEM;
			goto end;
		}
		found = true;
	}

end:
	if (dwfl)
		dwfl_end(dwfl);
	if (ret >= 0)
		ret = found ? 1 : 0;
	return ret;
}

/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
			       struct line_range *lr)
{
	/* Copy source path */
	if (!lr->path) {
		lr->path = strdup(src);
		if (lr->path == NULL)
			return -ENOMEM;
	}
	return line_list__add_line(&lr->line_list, lineno);
}

static int line_range_walk_cb(const char *fname, int lineno,
			      Dwarf_Addr addr __used,
			      void *data)
{
	struct line_finder *lf = data;

	if ((strtailcmp(fname, lf->fname) != 0) ||
	    (lf->lno_s > lineno || lf->lno_e < lineno))
		return 0;

	if (line_range_add_line(fname, lineno, lf->lr) < 0)
		return -EINVAL;

	return 0;
}

/* Find line range from its line number */
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
{
	int ret;

	ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);

	/* Update status */
	if (ret >= 0)
		if (!list_empty(&lf->lr->line_list))
			ret = lf->found = 1;
		else
			ret = 0;	/* Lines are not found */
	else {
		free(lf->lr->path);
		lf->lr->path = NULL;
	}
	return ret;
}

static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
	struct dwarf_callback_param *param = data;

	param->retval = find_line_range_by_line(in_die, param->data);
	return DWARF_CB_ABORT;	/* No need to find other instances */
}

/* Search function from function name */
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
{
	struct dwarf_callback_param *param = data;
	struct line_finder *lf = param->data;
	struct line_range *lr = lf->lr;

	/* Check declared file */
	if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
		return DWARF_CB_OK;

	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
	    die_compare_name(sp_die, lr->function)) {
		lf->fname = dwarf_decl_file(sp_die);
		dwarf_decl_line(sp_die, &lr->offset);
		pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
		lf->lno_s = lr->offset + lr->start;
		if (lf->lno_s < 0)	/* Overflow */
			lf->lno_s = INT_MAX;
		lf->lno_e = lr->offset + lr->end;
		if (lf->lno_e < 0)	/* Overflow */
			lf->lno_e = INT_MAX;
		pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
		lr->start = lf->lno_s;
		lr->end = lf->lno_e;
		if (dwarf_func_inline(sp_die)) {
			struct dwarf_callback_param _param;
			_param.data = (void *)lf;
			_param.retval = 0;
			dwarf_func_inline_instances(sp_die,
						    line_range_inline_cb,
						    &_param);
			param->retval = _param.retval;
		} else
			param->retval = find_line_range_by_line(sp_die, lf);
		return DWARF_CB_ABORT;
	}
	return DWARF_CB_OK;
}

static int find_line_range_by_func(struct line_finder *lf)
{
	struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
	dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
	return param.retval;
}

int find_line_range(int fd, struct line_range *lr)
{
	struct line_finder lf = {.lr = lr, .found = 0};
	int ret = 0;
	Dwarf_Off off = 0, noff;
	size_t cuhl;
	Dwarf_Die *diep;
	Dwarf *dbg = NULL;
	Dwfl *dwfl;
	Dwarf_Addr bias;	/* Currently ignored */
	const char *comp_dir;

	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
	if (!dbg) {
		pr_warning("No debug information found in the vmlinux - "
			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
		close(fd);	/* Without dwfl_end(), fd isn't closed. */
		return -EBADF;
	}

	/* Loop on CUs (Compilation Unit) */
	while (!lf.found && ret >= 0) {
		if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
			break;

		/* Get the DIE(Debugging Information Entry) of this CU */
		diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
		if (!diep)
			continue;

		/* Check if target file is included. */
		if (lr->file)
			lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
		else
			lf.fname = 0;

		if (!lr->file || lf.fname) {
			if (lr->function)
				ret = find_line_range_by_func(&lf);
			else {
				lf.lno_s = lr->start;
				lf.lno_e = lr->end;
				ret = find_line_range_by_line(NULL, &lf);
			}
		}
		off = noff;
	}

	/* Store comp_dir */
	if (lf.found) {
		comp_dir = cu_get_comp_dir(&lf.cu_die);
		if (comp_dir) {
			lr->comp_dir = strdup(comp_dir);
			if (!lr->comp_dir)
				ret = -ENOMEM;
		}
	}

	pr_debug("path: %s\n", lr->path);
	dwfl_end(dwfl);
	return (ret < 0) ? ret : lf.found;
}