aboutsummaryrefslogtreecommitdiff
path: root/gdb/dwarf2-frame.c
blob: f7dc820f4dbbd82d4accdfb5371e7752a201a4a0 (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
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
/* Frame unwinder for frames with DWARF Call Frame Information.

   Copyright (C) 2003-2018 Free Software Foundation, Inc.

   Contributed by Mark Kettenis.

   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 "dwarf2expr.h"
#include "dwarf2.h"
#include "frame.h"
#include "frame-base.h"
#include "frame-unwind.h"
#include "gdbcore.h"
#include "gdbtypes.h"
#include "symtab.h"
#include "objfiles.h"
#include "regcache.h"
#include "value.h"
#include "record.h"

#include "complaints.h"
#include "dwarf2-frame.h"
#include "dwarf2read.h"
#include "ax.h"
#include "dwarf2loc.h"
#include "dwarf2-frame-tailcall.h"
#if GDB_SELF_TEST
#include "selftest.h"
#include "selftest-arch.h"
#endif

struct comp_unit;

/* Call Frame Information (CFI).  */

/* Common Information Entry (CIE).  */

struct dwarf2_cie
{
  /* Computation Unit for this CIE.  */
  struct comp_unit *unit;

  /* Offset into the .debug_frame section where this CIE was found.
     Used to identify this CIE.  */
  ULONGEST cie_pointer;

  /* Constant that is factored out of all advance location
     instructions.  */
  ULONGEST code_alignment_factor;

  /* Constants that is factored out of all offset instructions.  */
  LONGEST data_alignment_factor;

  /* Return address column.  */
  ULONGEST return_address_register;

  /* Instruction sequence to initialize a register set.  */
  const gdb_byte *initial_instructions;
  const gdb_byte *end;

  /* Saved augmentation, in case it's needed later.  */
  char *augmentation;

  /* Encoding of addresses.  */
  gdb_byte encoding;

  /* Target address size in bytes.  */
  int addr_size;

  /* Target pointer size in bytes.  */
  int ptr_size;

  /* True if a 'z' augmentation existed.  */
  unsigned char saw_z_augmentation;

  /* True if an 'S' augmentation existed.  */
  unsigned char signal_frame;

  /* The version recorded in the CIE.  */
  unsigned char version;

  /* The segment size.  */
  unsigned char segment_size;
};

struct dwarf2_cie_table
{
  int num_entries;
  struct dwarf2_cie **entries;
};

/* Frame Description Entry (FDE).  */

struct dwarf2_fde
{
  /* CIE for this FDE.  */
  struct dwarf2_cie *cie;

  /* First location associated with this FDE.  */
  CORE_ADDR initial_location;

  /* Number of bytes of program instructions described by this FDE.  */
  CORE_ADDR address_range;

  /* Instruction sequence.  */
  const gdb_byte *instructions;
  const gdb_byte *end;

  /* True if this FDE is read from a .eh_frame instead of a .debug_frame
     section.  */
  unsigned char eh_frame_p;
};

struct dwarf2_fde_table
{
  int num_entries;
  struct dwarf2_fde **entries;
};

/* A minimal decoding of DWARF2 compilation units.  We only decode
   what's needed to get to the call frame information.  */

struct comp_unit
{
  /* Keep the bfd convenient.  */
  bfd *abfd;

  struct objfile *objfile;

  /* Pointer to the .debug_frame section loaded into memory.  */
  const gdb_byte *dwarf_frame_buffer;

  /* Length of the loaded .debug_frame section.  */
  bfd_size_type dwarf_frame_size;

  /* Pointer to the .debug_frame section.  */
  asection *dwarf_frame_section;

  /* Base for DW_EH_PE_datarel encodings.  */
  bfd_vma dbase;

  /* Base for DW_EH_PE_textrel encodings.  */
  bfd_vma tbase;
};

static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc,
						 CORE_ADDR *out_offset);

static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
				       int eh_frame_p);

static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
				     int ptr_len, const gdb_byte *buf,
				     unsigned int *bytes_read_ptr,
				     CORE_ADDR func_base);


/* See dwarf2-frame.h.  */
int dwarf2_frame_unwinders_enabled_p = 1;

/* Store the length the expression for the CFA in the `cfa_reg' field,
   which is unused in that case.  */
#define cfa_exp_len cfa_reg

dwarf2_frame_state::dwarf2_frame_state (CORE_ADDR pc_, struct dwarf2_cie *cie)
  : pc (pc_), data_align (cie->data_alignment_factor),
    code_align (cie->code_alignment_factor),
    retaddr_column (cie->return_address_register)
{
}


/* Helper functions for execute_stack_op.  */

static CORE_ADDR
read_addr_from_reg (struct frame_info *this_frame, int reg)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);

  return address_from_register (regnum, this_frame);
}

/* Execute the required actions for both the DW_CFA_restore and
DW_CFA_restore_extended instructions.  */
static void
dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
		     struct dwarf2_frame_state *fs, int eh_frame_p)
{
  ULONGEST reg;

  gdb_assert (fs->initial.reg);
  reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
  fs->regs.alloc_regs (reg + 1);

  /* Check if this register was explicitly initialized in the
  CIE initial instructions.  If not, default the rule to
  UNSPECIFIED.  */
  if (reg < fs->initial.num_regs)
    fs->regs.reg[reg] = fs->initial.reg[reg];
  else
    fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;

  if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
    {
      int regnum = dwarf_reg_to_regnum (gdbarch, reg);

      complaint (_("\
incomplete CFI data; DW_CFA_restore unspecified\n\
register %s (#%d) at %s"),
		 gdbarch_register_name (gdbarch, regnum), regnum,
		 paddress (gdbarch, fs->pc));
    }
}

class dwarf_expr_executor : public dwarf_expr_context
{
 public:

  struct frame_info *this_frame;

  CORE_ADDR read_addr_from_reg (int reg) override
  {
    return ::read_addr_from_reg (this_frame, reg);
  }

  struct value *get_reg_value (struct type *type, int reg) override
  {
    struct gdbarch *gdbarch = get_frame_arch (this_frame);
    int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);

    return value_from_register (type, regnum, this_frame);
  }

  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
  {
    read_memory (addr, buf, len);
  }

  void get_frame_base (const gdb_byte **start, size_t *length) override
  {
    invalid ("DW_OP_fbreg");
  }

  void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
				   union call_site_parameter_u kind_u,
				   int deref_size) override
  {
    invalid ("DW_OP_entry_value");
  }

  CORE_ADDR get_object_address () override
  {
    invalid ("DW_OP_push_object_address");
  }

  CORE_ADDR get_frame_cfa () override
  {
    invalid ("DW_OP_call_frame_cfa");
  }

  CORE_ADDR get_tls_address (CORE_ADDR offset) override
  {
    invalid ("DW_OP_form_tls_address");
  }

  void dwarf_call (cu_offset die_offset) override
  {
    invalid ("DW_OP_call*");
  }

  struct value *dwarf_variable_value (sect_offset sect_off) override
  {
    invalid ("DW_OP_GNU_variable_value");
  }

  CORE_ADDR get_addr_index (unsigned int index) override
  {
    invalid ("DW_OP_GNU_addr_index");
  }

 private:

  void invalid (const char *op) ATTRIBUTE_NORETURN
  {
    error (_("%s is invalid in this context"), op);
  }
};

static CORE_ADDR
execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
		  CORE_ADDR offset, struct frame_info *this_frame,
		  CORE_ADDR initial, int initial_in_stack_memory)
{
  CORE_ADDR result;

  dwarf_expr_executor ctx;
  scoped_value_mark free_values;

  ctx.this_frame = this_frame;
  ctx.gdbarch = get_frame_arch (this_frame);
  ctx.addr_size = addr_size;
  ctx.ref_addr_size = -1;
  ctx.offset = offset;

  ctx.push_address (initial, initial_in_stack_memory);
  ctx.eval (exp, len);

  if (ctx.location == DWARF_VALUE_MEMORY)
    result = ctx.fetch_address (0);
  else if (ctx.location == DWARF_VALUE_REGISTER)
    result = ctx.read_addr_from_reg (value_as_long (ctx.fetch (0)));
  else
    {
      /* This is actually invalid DWARF, but if we ever do run across
	 it somehow, we might as well support it.  So, instead, report
	 it as unimplemented.  */
      error (_("\
Not implemented: computing unwound register using explicit value operator"));
    }

  return result;
}


/* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
   PC.  Modify FS state accordingly.  Return current INSN_PTR where the
   execution has stopped, one can resume it on the next call.  */

static const gdb_byte *
execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
		     const gdb_byte *insn_end, struct gdbarch *gdbarch,
		     CORE_ADDR pc, struct dwarf2_frame_state *fs)
{
  int eh_frame_p = fde->eh_frame_p;
  unsigned int bytes_read;
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  while (insn_ptr < insn_end && fs->pc <= pc)
    {
      gdb_byte insn = *insn_ptr++;
      uint64_t utmp, reg;
      int64_t offset;

      if ((insn & 0xc0) == DW_CFA_advance_loc)
	fs->pc += (insn & 0x3f) * fs->code_align;
      else if ((insn & 0xc0) == DW_CFA_offset)
	{
	  reg = insn & 0x3f;
	  reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	  insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	  offset = utmp * fs->data_align;
	  fs->regs.alloc_regs (reg + 1);
	  fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
	  fs->regs.reg[reg].loc.offset = offset;
	}
      else if ((insn & 0xc0) == DW_CFA_restore)
	{
	  reg = insn & 0x3f;
	  dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
	}
      else
	{
	  switch (insn)
	    {
	    case DW_CFA_set_loc:
	      fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
					   fde->cie->ptr_size, insn_ptr,
					   &bytes_read, fde->initial_location);
	      /* Apply the objfile offset for relocatable objects.  */
	      fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
				  SECT_OFF_TEXT (fde->cie->unit->objfile));
	      insn_ptr += bytes_read;
	      break;

	    case DW_CFA_advance_loc1:
	      utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
	      fs->pc += utmp * fs->code_align;
	      insn_ptr++;
	      break;
	    case DW_CFA_advance_loc2:
	      utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
	      fs->pc += utmp * fs->code_align;
	      insn_ptr += 2;
	      break;
	    case DW_CFA_advance_loc4:
	      utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
	      fs->pc += utmp * fs->code_align;
	      insn_ptr += 4;
	      break;

	    case DW_CFA_offset_extended:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      offset = utmp * fs->data_align;
	      fs->regs.alloc_regs (reg + 1);
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
	      fs->regs.reg[reg].loc.offset = offset;
	      break;

	    case DW_CFA_restore_extended:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
	      break;

	    case DW_CFA_undefined:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	      fs->regs.alloc_regs (reg + 1);
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
	      break;

	    case DW_CFA_same_value:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	      fs->regs.alloc_regs (reg + 1);
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
	      break;

	    case DW_CFA_register:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
	      fs->regs.alloc_regs (reg + 1);
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
	      fs->regs.reg[reg].loc.reg = utmp;
	      break;

	    case DW_CFA_remember_state:
	      {
		struct dwarf2_frame_state_reg_info *new_rs;

		new_rs = new dwarf2_frame_state_reg_info (fs->regs);
		fs->regs.prev = new_rs;
	      }
	      break;

	    case DW_CFA_restore_state:
	      {
		struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;

		if (old_rs == NULL)
		  {
		    complaint (_("\
bad CFI data; mismatched DW_CFA_restore_state at %s"),
			       paddress (gdbarch, fs->pc));
		  }
		else
		  fs->regs = std::move (*old_rs);
	      }
	      break;

	    case DW_CFA_def_cfa:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      fs->regs.cfa_reg = reg;
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);

	      if (fs->armcc_cfa_offsets_sf)
		utmp *= fs->data_align;

	      fs->regs.cfa_offset = utmp;
	      fs->regs.cfa_how = CFA_REG_OFFSET;
	      break;

	    case DW_CFA_def_cfa_register:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
                                                             eh_frame_p);
	      fs->regs.cfa_how = CFA_REG_OFFSET;
	      break;

	    case DW_CFA_def_cfa_offset:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);

	      if (fs->armcc_cfa_offsets_sf)
		utmp *= fs->data_align;

	      fs->regs.cfa_offset = utmp;
	      /* cfa_how deliberately not set.  */
	      break;

	    case DW_CFA_nop:
	      break;

	    case DW_CFA_def_cfa_expression:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      fs->regs.cfa_exp_len = utmp;
	      fs->regs.cfa_exp = insn_ptr;
	      fs->regs.cfa_how = CFA_EXP;
	      insn_ptr += fs->regs.cfa_exp_len;
	      break;

	    case DW_CFA_expression:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	      fs->regs.alloc_regs (reg + 1);
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      fs->regs.reg[reg].loc.exp.start = insn_ptr;
	      fs->regs.reg[reg].loc.exp.len = utmp;
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
	      insn_ptr += utmp;
	      break;

	    case DW_CFA_offset_extended_sf:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	      insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
	      offset *= fs->data_align;
	      fs->regs.alloc_regs (reg + 1);
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
	      fs->regs.reg[reg].loc.offset = offset;
	      break;

	    case DW_CFA_val_offset:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      fs->regs.alloc_regs (reg + 1);
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      offset = utmp * fs->data_align;
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
	      fs->regs.reg[reg].loc.offset = offset;
	      break;

	    case DW_CFA_val_offset_sf:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      fs->regs.alloc_regs (reg + 1);
	      insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
	      offset *= fs->data_align;
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
	      fs->regs.reg[reg].loc.offset = offset;
	      break;

	    case DW_CFA_val_expression:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      fs->regs.alloc_regs (reg + 1);
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      fs->regs.reg[reg].loc.exp.start = insn_ptr;
	      fs->regs.reg[reg].loc.exp.len = utmp;
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
	      insn_ptr += utmp;
	      break;

	    case DW_CFA_def_cfa_sf:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
                                                             eh_frame_p);
	      insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
	      fs->regs.cfa_offset = offset * fs->data_align;
	      fs->regs.cfa_how = CFA_REG_OFFSET;
	      break;

	    case DW_CFA_def_cfa_offset_sf:
	      insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
	      fs->regs.cfa_offset = offset * fs->data_align;
	      /* cfa_how deliberately not set.  */
	      break;

	    case DW_CFA_GNU_args_size:
	      /* Ignored.  */
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      break;

	    case DW_CFA_GNU_negative_offset_extended:
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
	      reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
	      insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
	      offset = utmp * fs->data_align;
	      fs->regs.alloc_regs (reg + 1);
	      fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
	      fs->regs.reg[reg].loc.offset = -offset;
	      break;

	    default:
	      if (insn >= DW_CFA_lo_user && insn <= DW_CFA_hi_user)
		{
		  /* Handle vendor-specific CFI for different architectures.  */
		  if (!gdbarch_execute_dwarf_cfa_vendor_op (gdbarch, insn, fs))
		    error (_("Call Frame Instruction op %d in vendor extension "
			     "space is not handled on this architecture."),
			   insn);
		}
	      else
		internal_error (__FILE__, __LINE__,
				_("Unknown CFI encountered."));
	    }
	}
    }

  if (fs->initial.reg == NULL)
    {
      /* Don't allow remember/restore between CIE and FDE programs.  */
      delete fs->regs.prev;
      fs->regs.prev = NULL;
    }

  return insn_ptr;
}

#if GDB_SELF_TEST

namespace selftests {

/* Unit test to function execute_cfa_program.  */

static void
execute_cfa_program_test (struct gdbarch *gdbarch)
{
  struct dwarf2_fde fde;
  struct dwarf2_cie cie;

  memset (&fde, 0, sizeof fde);
  memset (&cie, 0, sizeof cie);

  cie.data_alignment_factor = -4;
  cie.code_alignment_factor = 2;
  fde.cie = &cie;

  dwarf2_frame_state fs (0, fde.cie);

  gdb_byte insns[] =
    {
      DW_CFA_def_cfa, 1, 4,  /* DW_CFA_def_cfa: r1 ofs 4 */
      DW_CFA_offset | 0x2, 1,  /* DW_CFA_offset: r2 at cfa-4 */
      DW_CFA_remember_state,
      DW_CFA_restore_state,
    };

  const gdb_byte *insn_end = insns + sizeof (insns);
  const gdb_byte *out = execute_cfa_program (&fde, insns, insn_end, gdbarch,
					     0, &fs);

  SELF_CHECK (out == insn_end);
  SELF_CHECK (fs.pc == 0);

  /* The instructions above only use r1 and r2, but the register numbers
     used are adjusted by dwarf2_frame_adjust_regnum.  */
  auto r1 = dwarf2_frame_adjust_regnum (gdbarch, 1, fde.eh_frame_p);
  auto r2 = dwarf2_frame_adjust_regnum (gdbarch, 2, fde.eh_frame_p);

  SELF_CHECK (fs.regs.num_regs == (std::max (r1, r2) + 1));

  SELF_CHECK (fs.regs.reg[r2].how == DWARF2_FRAME_REG_SAVED_OFFSET);
  SELF_CHECK (fs.regs.reg[r2].loc.offset == -4);

  for (auto i = 0; i < fs.regs.num_regs; i++)
    if (i != r2)
      SELF_CHECK (fs.regs.reg[i].how == DWARF2_FRAME_REG_UNSPECIFIED);

  SELF_CHECK (fs.regs.cfa_reg == 1);
  SELF_CHECK (fs.regs.cfa_offset == 4);
  SELF_CHECK (fs.regs.cfa_how == CFA_REG_OFFSET);
  SELF_CHECK (fs.regs.cfa_exp == NULL);
  SELF_CHECK (fs.regs.prev == NULL);
}

} // namespace selftests
#endif /* GDB_SELF_TEST */



/* Architecture-specific operations.  */

/* Per-architecture data key.  */
static struct gdbarch_data *dwarf2_frame_data;

struct dwarf2_frame_ops
{
  /* Pre-initialize the register state REG for register REGNUM.  */
  void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
		    struct frame_info *);

  /* Check whether the THIS_FRAME is a signal trampoline.  */
  int (*signal_frame_p) (struct gdbarch *, struct frame_info *);

  /* Convert .eh_frame register number to DWARF register number, or
     adjust .debug_frame register number.  */
  int (*adjust_regnum) (struct gdbarch *, int, int);
};

/* Default architecture-specific register state initialization
   function.  */

static void
dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
			       struct dwarf2_frame_state_reg *reg,
			       struct frame_info *this_frame)
{
  /* If we have a register that acts as a program counter, mark it as
     a destination for the return address.  If we have a register that
     serves as the stack pointer, arrange for it to be filled with the
     call frame address (CFA).  The other registers are marked as
     unspecified.

     We copy the return address to the program counter, since many
     parts in GDB assume that it is possible to get the return address
     by unwinding the program counter register.  However, on ISA's
     with a dedicated return address register, the CFI usually only
     contains information to unwind that return address register.

     The reason we're treating the stack pointer special here is
     because in many cases GCC doesn't emit CFI for the stack pointer
     and implicitly assumes that it is equal to the CFA.  This makes
     some sense since the DWARF specification (version 3, draft 8,
     p. 102) says that:

     "Typically, the CFA is defined to be the value of the stack
     pointer at the call site in the previous frame (which may be
     different from its value on entry to the current frame)."

     However, this isn't true for all platforms supported by GCC
     (e.g. IBM S/390 and zSeries).  Those architectures should provide
     their own architecture-specific initialization function.  */

  if (regnum == gdbarch_pc_regnum (gdbarch))
    reg->how = DWARF2_FRAME_REG_RA;
  else if (regnum == gdbarch_sp_regnum (gdbarch))
    reg->how = DWARF2_FRAME_REG_CFA;
}

/* Return a default for the architecture-specific operations.  */

static void *
dwarf2_frame_init (struct obstack *obstack)
{
  struct dwarf2_frame_ops *ops;
  
  ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
  ops->init_reg = dwarf2_frame_default_init_reg;
  return ops;
}

/* Set the architecture-specific register state initialization
   function for GDBARCH to INIT_REG.  */

void
dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
			   void (*init_reg) (struct gdbarch *, int,
					     struct dwarf2_frame_state_reg *,
					     struct frame_info *))
{
  struct dwarf2_frame_ops *ops
    = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);

  ops->init_reg = init_reg;
}

/* Pre-initialize the register state REG for register REGNUM.  */

static void
dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
		       struct dwarf2_frame_state_reg *reg,
		       struct frame_info *this_frame)
{
  struct dwarf2_frame_ops *ops
    = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);

  ops->init_reg (gdbarch, regnum, reg, this_frame);
}

/* Set the architecture-specific signal trampoline recognition
   function for GDBARCH to SIGNAL_FRAME_P.  */

void
dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
				 int (*signal_frame_p) (struct gdbarch *,
							struct frame_info *))
{
  struct dwarf2_frame_ops *ops
    = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);

  ops->signal_frame_p = signal_frame_p;
}

/* Query the architecture-specific signal frame recognizer for
   THIS_FRAME.  */

static int
dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
			     struct frame_info *this_frame)
{
  struct dwarf2_frame_ops *ops
    = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);

  if (ops->signal_frame_p == NULL)
    return 0;
  return ops->signal_frame_p (gdbarch, this_frame);
}

/* Set the architecture-specific adjustment of .eh_frame and .debug_frame
   register numbers.  */

void
dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
				int (*adjust_regnum) (struct gdbarch *,
						      int, int))
{
  struct dwarf2_frame_ops *ops
    = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);

  ops->adjust_regnum = adjust_regnum;
}

/* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
   register.  */

static int
dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
			    int regnum, int eh_frame_p)
{
  struct dwarf2_frame_ops *ops
    = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);

  if (ops->adjust_regnum == NULL)
    return regnum;
  return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
}

static void
dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
			  struct dwarf2_fde *fde)
{
  struct compunit_symtab *cust;

  cust = find_pc_compunit_symtab (fs->pc);
  if (cust == NULL)
    return;

  if (producer_is_realview (COMPUNIT_PRODUCER (cust)))
    {
      if (fde->cie->version == 1)
	fs->armcc_cfa_offsets_sf = 1;

      if (fde->cie->version == 1)
	fs->armcc_cfa_offsets_reversed = 1;

      /* The reversed offset problem is present in some compilers
	 using DWARF3, but it was eventually fixed.  Check the ARM
	 defined augmentations, which are in the format "armcc" followed
	 by a list of one-character options.  The "+" option means
	 this problem is fixed (no quirk needed).  If the armcc
	 augmentation is missing, the quirk is needed.  */
      if (fde->cie->version == 3
	  && (!startswith (fde->cie->augmentation, "armcc")
	      || strchr (fde->cie->augmentation + 5, '+') == NULL))
	fs->armcc_cfa_offsets_reversed = 1;

      return;
    }
}


/* See dwarf2-frame.h.  */

int
dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
		       struct dwarf2_per_cu_data *data,
		       int *regnum_out, LONGEST *offset_out,
		       CORE_ADDR *text_offset_out,
		       const gdb_byte **cfa_start_out,
		       const gdb_byte **cfa_end_out)
{
  struct dwarf2_fde *fde;
  CORE_ADDR text_offset;
  CORE_ADDR pc1 = pc;

  /* Find the correct FDE.  */
  fde = dwarf2_frame_find_fde (&pc1, &text_offset);
  if (fde == NULL)
    error (_("Could not compute CFA; needed to translate this expression"));

  dwarf2_frame_state fs (pc1, fde->cie);

  /* Check for "quirks" - known bugs in producers.  */
  dwarf2_frame_find_quirks (&fs, fde);

  /* First decode all the insns in the CIE.  */
  execute_cfa_program (fde, fde->cie->initial_instructions,
		       fde->cie->end, gdbarch, pc, &fs);

  /* Save the initialized register set.  */
  fs.initial = fs.regs;

  /* Then decode the insns in the FDE up to our target PC.  */
  execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);

  /* Calculate the CFA.  */
  switch (fs.regs.cfa_how)
    {
    case CFA_REG_OFFSET:
      {
	int regnum = dwarf_reg_to_regnum_or_error (gdbarch, fs.regs.cfa_reg);

	*regnum_out = regnum;
	if (fs.armcc_cfa_offsets_reversed)
	  *offset_out = -fs.regs.cfa_offset;
	else
	  *offset_out = fs.regs.cfa_offset;
	return 1;
      }

    case CFA_EXP:
      *text_offset_out = text_offset;
      *cfa_start_out = fs.regs.cfa_exp;
      *cfa_end_out = fs.regs.cfa_exp + fs.regs.cfa_exp_len;
      return 0;

    default:
      internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
    }
}


struct dwarf2_frame_cache
{
  /* DWARF Call Frame Address.  */
  CORE_ADDR cfa;

  /* Set if the return address column was marked as unavailable
     (required non-collected memory or registers to compute).  */
  int unavailable_retaddr;

  /* Set if the return address column was marked as undefined.  */
  int undefined_retaddr;

  /* Saved registers, indexed by GDB register number, not by DWARF
     register number.  */
  struct dwarf2_frame_state_reg *reg;

  /* Return address register.  */
  struct dwarf2_frame_state_reg retaddr_reg;

  /* Target address size in bytes.  */
  int addr_size;

  /* The .text offset.  */
  CORE_ADDR text_offset;

  /* True if we already checked whether this frame is the bottom frame
     of a virtual tail call frame chain.  */
  int checked_tailcall_bottom;

  /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
     sequence.  If NULL then it is a normal case with no TAILCALL_FRAME
     involved.  Non-bottom frames of a virtual tail call frames chain use
     dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
     them.  */
  void *tailcall_cache;

  /* The number of bytes to subtract from TAILCALL_FRAME frames frame
     base to get the SP, to simulate the return address pushed on the
     stack.  */
  LONGEST entry_cfa_sp_offset;
  int entry_cfa_sp_offset_p;
};

static struct dwarf2_frame_cache *
dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  const int num_regs = gdbarch_num_regs (gdbarch)
		       + gdbarch_num_pseudo_regs (gdbarch);
  struct dwarf2_frame_cache *cache;
  struct dwarf2_fde *fde;
  CORE_ADDR entry_pc;
  const gdb_byte *instr;

  if (*this_cache)
    return (struct dwarf2_frame_cache *) *this_cache;

  /* Allocate a new cache.  */
  cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
  cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
  *this_cache = cache;

  /* Unwind the PC.

     Note that if the next frame is never supposed to return (i.e. a call
     to abort), the compiler might optimize away the instruction at
     its return address.  As a result the return address will
     point at some random instruction, and the CFI for that
     instruction is probably worthless to us.  GCC's unwinder solves
     this problem by substracting 1 from the return address to get an
     address in the middle of a presumed call instruction (or the
     instruction in the associated delay slot).  This should only be
     done for "normal" frames and not for resume-type frames (signal
     handlers, sentinel frames, dummy frames).  The function
     get_frame_address_in_block does just this.  It's not clear how
     reliable the method is though; there is the potential for the
     register state pre-call being different to that on return.  */
  CORE_ADDR pc1 = get_frame_address_in_block (this_frame);

  /* Find the correct FDE.  */
  fde = dwarf2_frame_find_fde (&pc1, &cache->text_offset);
  gdb_assert (fde != NULL);

  /* Allocate and initialize the frame state.  */
  struct dwarf2_frame_state fs (pc1, fde->cie);

  cache->addr_size = fde->cie->addr_size;

  /* Check for "quirks" - known bugs in producers.  */
  dwarf2_frame_find_quirks (&fs, fde);

  /* First decode all the insns in the CIE.  */
  execute_cfa_program (fde, fde->cie->initial_instructions,
		       fde->cie->end, gdbarch,
		       get_frame_address_in_block (this_frame), &fs);

  /* Save the initialized register set.  */
  fs.initial = fs.regs;

  if (get_frame_func_if_available (this_frame, &entry_pc))
    {
      /* Decode the insns in the FDE up to the entry PC.  */
      instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
				   entry_pc, &fs);

      if (fs.regs.cfa_how == CFA_REG_OFFSET
	  && (dwarf_reg_to_regnum (gdbarch, fs.regs.cfa_reg)
	      == gdbarch_sp_regnum (gdbarch)))
	{
	  cache->entry_cfa_sp_offset = fs.regs.cfa_offset;
	  cache->entry_cfa_sp_offset_p = 1;
	}
    }
  else
    instr = fde->instructions;

  /* Then decode the insns in the FDE up to our target PC.  */
  execute_cfa_program (fde, instr, fde->end, gdbarch,
		       get_frame_address_in_block (this_frame), &fs);

  TRY
    {
      /* Calculate the CFA.  */
      switch (fs.regs.cfa_how)
	{
	case CFA_REG_OFFSET:
	  cache->cfa = read_addr_from_reg (this_frame, fs.regs.cfa_reg);
	  if (fs.armcc_cfa_offsets_reversed)
	    cache->cfa -= fs.regs.cfa_offset;
	  else
	    cache->cfa += fs.regs.cfa_offset;
	  break;

	case CFA_EXP:
	  cache->cfa =
	    execute_stack_op (fs.regs.cfa_exp, fs.regs.cfa_exp_len,
			      cache->addr_size, cache->text_offset,
			      this_frame, 0, 0);
	  break;

	default:
	  internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
	}
    }
  CATCH (ex, RETURN_MASK_ERROR)
    {
      if (ex.error == NOT_AVAILABLE_ERROR)
	{
	  cache->unavailable_retaddr = 1;
	  return cache;
	}

      throw_exception (ex);
    }
  END_CATCH

  /* Initialize the register state.  */
  {
    int regnum;

    for (regnum = 0; regnum < num_regs; regnum++)
      dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
  }

  /* Go through the DWARF2 CFI generated table and save its register
     location information in the cache.  Note that we don't skip the
     return address column; it's perfectly all right for it to
     correspond to a real register.  */
  {
    int column;		/* CFI speak for "register number".  */

    for (column = 0; column < fs.regs.num_regs; column++)
      {
	/* Use the GDB register number as the destination index.  */
	int regnum = dwarf_reg_to_regnum (gdbarch, column);

	/* Protect against a target returning a bad register.  */
	if (regnum < 0 || regnum >= num_regs)
	  continue;

	/* NOTE: cagney/2003-09-05: CFI should specify the disposition
	   of all debug info registers.  If it doesn't, complain (but
	   not too loudly).  It turns out that GCC assumes that an
	   unspecified register implies "same value" when CFI (draft
	   7) specifies nothing at all.  Such a register could equally
	   be interpreted as "undefined".  Also note that this check
	   isn't sufficient; it only checks that all registers in the
	   range [0 .. max column] are specified, and won't detect
	   problems when a debug info register falls outside of the
	   table.  We need a way of iterating through all the valid
	   DWARF2 register numbers.  */
	if (fs.regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
	  {
	    if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
	      complaint (_("\
incomplete CFI data; unspecified registers (e.g., %s) at %s"),
			 gdbarch_register_name (gdbarch, regnum),
			 paddress (gdbarch, fs.pc));
	  }
	else
	  cache->reg[regnum] = fs.regs.reg[column];
      }
  }

  /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
     we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules.  */
  {
    int regnum;

    for (regnum = 0; regnum < num_regs; regnum++)
      {
	if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
	    || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
	  {
	    struct dwarf2_frame_state_reg *retaddr_reg =
	      &fs.regs.reg[fs.retaddr_column];

	    /* It seems rather bizarre to specify an "empty" column as
               the return adress column.  However, this is exactly
               what GCC does on some targets.  It turns out that GCC
               assumes that the return address can be found in the
               register corresponding to the return address column.
               Incidentally, that's how we should treat a return
               address column specifying "same value" too.  */
	    if (fs.retaddr_column < fs.regs.num_regs
		&& retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
		&& retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
	      {
		if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
		  cache->reg[regnum] = *retaddr_reg;
		else
		  cache->retaddr_reg = *retaddr_reg;
	      }
	    else
	      {
		if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
		  {
		    cache->reg[regnum].loc.reg = fs.retaddr_column;
		    cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
		  }
		else
		  {
		    cache->retaddr_reg.loc.reg = fs.retaddr_column;
		    cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
		  }
	      }
	  }
      }
  }

  if (fs.retaddr_column < fs.regs.num_regs
      && fs.regs.reg[fs.retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
    cache->undefined_retaddr = 1;

  return cache;
}

static enum unwind_stop_reason
dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
				 void **this_cache)
{
  struct dwarf2_frame_cache *cache
    = dwarf2_frame_cache (this_frame, this_cache);

  if (cache->unavailable_retaddr)
    return UNWIND_UNAVAILABLE;

  if (cache->undefined_retaddr)
    return UNWIND_OUTERMOST;

  return UNWIND_NO_REASON;
}

static void
dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
		      struct frame_id *this_id)
{
  struct dwarf2_frame_cache *cache =
    dwarf2_frame_cache (this_frame, this_cache);

  if (cache->unavailable_retaddr)
    (*this_id) = frame_id_build_unavailable_stack (get_frame_func (this_frame));
  else if (cache->undefined_retaddr)
    return;
  else
    (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
}

static struct value *
dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
			    int regnum)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  struct dwarf2_frame_cache *cache =
    dwarf2_frame_cache (this_frame, this_cache);
  CORE_ADDR addr;
  int realnum;

  /* Check whether THIS_FRAME is the bottom frame of a virtual tail
     call frame chain.  */
  if (!cache->checked_tailcall_bottom)
    {
      cache->checked_tailcall_bottom = 1;
      dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
				     (cache->entry_cfa_sp_offset_p
				      ? &cache->entry_cfa_sp_offset : NULL));
    }

  /* Non-bottom frames of a virtual tail call frames chain use
     dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
     them.  If dwarf2_tailcall_prev_register_first does not have specific value
     unwind the register, tail call frames are assumed to have the register set
     of the top caller.  */
  if (cache->tailcall_cache)
    {
      struct value *val;
      
      val = dwarf2_tailcall_prev_register_first (this_frame,
						 &cache->tailcall_cache,
						 regnum);
      if (val)
	return val;
    }

  switch (cache->reg[regnum].how)
    {
    case DWARF2_FRAME_REG_UNDEFINED:
      /* If CFI explicitly specified that the value isn't defined,
	 mark it as optimized away; the value isn't available.  */
      return frame_unwind_got_optimized (this_frame, regnum);

    case DWARF2_FRAME_REG_SAVED_OFFSET:
      addr = cache->cfa + cache->reg[regnum].loc.offset;
      return frame_unwind_got_memory (this_frame, regnum, addr);

    case DWARF2_FRAME_REG_SAVED_REG:
      realnum = dwarf_reg_to_regnum_or_error
	(gdbarch, cache->reg[regnum].loc.reg);
      return frame_unwind_got_register (this_frame, regnum, realnum);

    case DWARF2_FRAME_REG_SAVED_EXP:
      addr = execute_stack_op (cache->reg[regnum].loc.exp.start,
			       cache->reg[regnum].loc.exp.len,
			       cache->addr_size, cache->text_offset,
			       this_frame, cache->cfa, 1);
      return frame_unwind_got_memory (this_frame, regnum, addr);

    case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
      addr = cache->cfa + cache->reg[regnum].loc.offset;
      return frame_unwind_got_constant (this_frame, regnum, addr);

    case DWARF2_FRAME_REG_SAVED_VAL_EXP:
      addr = execute_stack_op (cache->reg[regnum].loc.exp.start,
			       cache->reg[regnum].loc.exp.len,
			       cache->addr_size, cache->text_offset,
			       this_frame, cache->cfa, 1);
      return frame_unwind_got_constant (this_frame, regnum, addr);

    case DWARF2_FRAME_REG_UNSPECIFIED:
      /* GCC, in its infinite wisdom decided to not provide unwind
	 information for registers that are "same value".  Since
	 DWARF2 (3 draft 7) doesn't define such behavior, said
	 registers are actually undefined (which is different to CFI
	 "undefined").  Code above issues a complaint about this.
	 Here just fudge the books, assume GCC, and that the value is
	 more inner on the stack.  */
      return frame_unwind_got_register (this_frame, regnum, regnum);

    case DWARF2_FRAME_REG_SAME_VALUE:
      return frame_unwind_got_register (this_frame, regnum, regnum);

    case DWARF2_FRAME_REG_CFA:
      return frame_unwind_got_address (this_frame, regnum, cache->cfa);

    case DWARF2_FRAME_REG_CFA_OFFSET:
      addr = cache->cfa + cache->reg[regnum].loc.offset;
      return frame_unwind_got_address (this_frame, regnum, addr);

    case DWARF2_FRAME_REG_RA_OFFSET:
      addr = cache->reg[regnum].loc.offset;
      regnum = dwarf_reg_to_regnum_or_error
	(gdbarch, cache->retaddr_reg.loc.reg);
      addr += get_frame_register_unsigned (this_frame, regnum);
      return frame_unwind_got_address (this_frame, regnum, addr);

    case DWARF2_FRAME_REG_FN:
      return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);

    default:
      internal_error (__FILE__, __LINE__, _("Unknown register rule."));
    }
}

/* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
   call frames chain.  */

static void
dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache)
{
  struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache);

  if (cache->tailcall_cache)
    dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache);
}

static int
dwarf2_frame_sniffer (const struct frame_unwind *self,
		      struct frame_info *this_frame, void **this_cache)
{
  if (!dwarf2_frame_unwinders_enabled_p)
    return 0;

  /* Grab an address that is guarenteed to reside somewhere within the
     function.  get_frame_pc(), with a no-return next function, can
     end up returning something past the end of this function's body.
     If the frame we're sniffing for is a signal frame whose start
     address is placed on the stack by the OS, its FDE must
     extend one byte before its start address or we could potentially
     select the FDE of the previous function.  */
  CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
  struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);

  if (!fde)
    return 0;

  /* On some targets, signal trampolines may have unwind information.
     We need to recognize them so that we set the frame type
     correctly.  */

  if (fde->cie->signal_frame
      || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
				      this_frame))
    return self->type == SIGTRAMP_FRAME;

  if (self->type != NORMAL_FRAME)
    return 0;

  return 1;
}

static const struct frame_unwind dwarf2_frame_unwind =
{
  NORMAL_FRAME,
  dwarf2_frame_unwind_stop_reason,
  dwarf2_frame_this_id,
  dwarf2_frame_prev_register,
  NULL,
  dwarf2_frame_sniffer,
  dwarf2_frame_dealloc_cache
};

static const struct frame_unwind dwarf2_signal_frame_unwind =
{
  SIGTRAMP_FRAME,
  dwarf2_frame_unwind_stop_reason,
  dwarf2_frame_this_id,
  dwarf2_frame_prev_register,
  NULL,
  dwarf2_frame_sniffer,

  /* TAILCALL_CACHE can never be in such frame to need dealloc_cache.  */
  NULL
};

/* Append the DWARF-2 frame unwinders to GDBARCH's list.  */

void
dwarf2_append_unwinders (struct gdbarch *gdbarch)
{
  /* TAILCALL_FRAME must be first to find the record by
     dwarf2_tailcall_sniffer_first.  */
  frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind);

  frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
  frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
}


/* There is no explicitly defined relationship between the CFA and the
   location of frame's local variables and arguments/parameters.
   Therefore, frame base methods on this page should probably only be
   used as a last resort, just to avoid printing total garbage as a
   response to the "info frame" command.  */

static CORE_ADDR
dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
{
  struct dwarf2_frame_cache *cache =
    dwarf2_frame_cache (this_frame, this_cache);

  return cache->cfa;
}

static const struct frame_base dwarf2_frame_base =
{
  &dwarf2_frame_unwind,
  dwarf2_frame_base_address,
  dwarf2_frame_base_address,
  dwarf2_frame_base_address
};

const struct frame_base *
dwarf2_frame_base_sniffer (struct frame_info *this_frame)
{
  CORE_ADDR block_addr = get_frame_address_in_block (this_frame);

  if (dwarf2_frame_find_fde (&block_addr, NULL))
    return &dwarf2_frame_base;

  return NULL;
}

/* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
   the DWARF unwinder.  This is used to implement
   DW_OP_call_frame_cfa.  */

CORE_ADDR
dwarf2_frame_cfa (struct frame_info *this_frame)
{
  if (frame_unwinder_is (this_frame, &record_btrace_tailcall_frame_unwind)
      || frame_unwinder_is (this_frame, &record_btrace_frame_unwind))
    throw_error (NOT_AVAILABLE_ERROR,
		 _("cfa not available for record btrace target"));

  while (get_frame_type (this_frame) == INLINE_FRAME)
    this_frame = get_prev_frame (this_frame);
  if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
    throw_error (NOT_AVAILABLE_ERROR,
                _("can't compute CFA for this frame: "
                  "required registers or memory are unavailable"));

  if (get_frame_id (this_frame).stack_status != FID_STACK_VALID)
    throw_error (NOT_AVAILABLE_ERROR,
                _("can't compute CFA for this frame: "
                  "frame base not available"));

  return get_frame_base (this_frame);
}

const struct objfile_data *dwarf2_frame_objfile_data;

static unsigned int
read_1_byte (bfd *abfd, const gdb_byte *buf)
{
  return bfd_get_8 (abfd, buf);
}

static unsigned int
read_4_bytes (bfd *abfd, const gdb_byte *buf)
{
  return bfd_get_32 (abfd, buf);
}

static ULONGEST
read_8_bytes (bfd *abfd, const gdb_byte *buf)
{
  return bfd_get_64 (abfd, buf);
}

static ULONGEST
read_initial_length (bfd *abfd, const gdb_byte *buf,
		     unsigned int *bytes_read_ptr)
{
  LONGEST result;

  result = bfd_get_32 (abfd, buf);
  if (result == 0xffffffff)
    {
      result = bfd_get_64 (abfd, buf + 4);
      *bytes_read_ptr = 12;
    }
  else
    *bytes_read_ptr = 4;

  return result;
}


/* Pointer encoding helper functions.  */

/* GCC supports exception handling based on DWARF2 CFI.  However, for
   technical reasons, it encodes addresses in its FDE's in a different
   way.  Several "pointer encodings" are supported.  The encoding
   that's used for a particular FDE is determined by the 'R'
   augmentation in the associated CIE.  The argument of this
   augmentation is a single byte.  

   The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
   LEB128.  This is encoded in bits 0, 1 and 2.  Bit 3 encodes whether
   the address is signed or unsigned.  Bits 4, 5 and 6 encode how the
   address should be interpreted (absolute, relative to the current
   position in the FDE, ...).  Bit 7, indicates that the address
   should be dereferenced.  */

static gdb_byte
encoding_for_size (unsigned int size)
{
  switch (size)
    {
    case 2:
      return DW_EH_PE_udata2;
    case 4:
      return DW_EH_PE_udata4;
    case 8:
      return DW_EH_PE_udata8;
    default:
      internal_error (__FILE__, __LINE__, _("Unsupported address size"));
    }
}

static CORE_ADDR
read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
		    int ptr_len, const gdb_byte *buf,
		    unsigned int *bytes_read_ptr,
		    CORE_ADDR func_base)
{
  ptrdiff_t offset;
  CORE_ADDR base;

  /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
     FDE's.  */
  if (encoding & DW_EH_PE_indirect)
    internal_error (__FILE__, __LINE__, 
		    _("Unsupported encoding: DW_EH_PE_indirect"));

  *bytes_read_ptr = 0;

  switch (encoding & 0x70)
    {
    case DW_EH_PE_absptr:
      base = 0;
      break;
    case DW_EH_PE_pcrel:
      base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
      base += (buf - unit->dwarf_frame_buffer);
      break;
    case DW_EH_PE_datarel:
      base = unit->dbase;
      break;
    case DW_EH_PE_textrel:
      base = unit->tbase;
      break;
    case DW_EH_PE_funcrel:
      base = func_base;
      break;
    case DW_EH_PE_aligned:
      base = 0;
      offset = buf - unit->dwarf_frame_buffer;
      if ((offset % ptr_len) != 0)
	{
	  *bytes_read_ptr = ptr_len - (offset % ptr_len);
	  buf += *bytes_read_ptr;
	}
      break;
    default:
      internal_error (__FILE__, __LINE__,
		      _("Invalid or unsupported encoding"));
    }

  if ((encoding & 0x07) == 0x00)
    {
      encoding |= encoding_for_size (ptr_len);
      if (bfd_get_sign_extend_vma (unit->abfd))
	encoding |= DW_EH_PE_signed;
    }

  switch (encoding & 0x0f)
    {
    case DW_EH_PE_uleb128:
      {
	uint64_t value;
	const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;

	*bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf;
	return base + value;
      }
    case DW_EH_PE_udata2:
      *bytes_read_ptr += 2;
      return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
    case DW_EH_PE_udata4:
      *bytes_read_ptr += 4;
      return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
    case DW_EH_PE_udata8:
      *bytes_read_ptr += 8;
      return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
    case DW_EH_PE_sleb128:
      {
	int64_t value;
	const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;

	*bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf;
	return base + value;
      }
    case DW_EH_PE_sdata2:
      *bytes_read_ptr += 2;
      return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
    case DW_EH_PE_sdata4:
      *bytes_read_ptr += 4;
      return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
    case DW_EH_PE_sdata8:
      *bytes_read_ptr += 8;
      return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
    default:
      internal_error (__FILE__, __LINE__,
		      _("Invalid or unsupported encoding"));
    }
}


static int
bsearch_cie_cmp (const void *key, const void *element)
{
  ULONGEST cie_pointer = *(ULONGEST *) key;
  struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;

  if (cie_pointer == cie->cie_pointer)
    return 0;

  return (cie_pointer < cie->cie_pointer) ? -1 : 1;
}

/* Find CIE with the given CIE_POINTER in CIE_TABLE.  */
static struct dwarf2_cie *
find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
{
  struct dwarf2_cie **p_cie;

  /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
     bsearch be non-NULL.  */
  if (cie_table->entries == NULL)
    {
      gdb_assert (cie_table->num_entries == 0);
      return NULL;
    }

  p_cie = ((struct dwarf2_cie **)
	   bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
		    sizeof (cie_table->entries[0]), bsearch_cie_cmp));
  if (p_cie != NULL)
    return *p_cie;
  return NULL;
}

/* Add a pointer to new CIE to the CIE_TABLE, allocating space for it.  */
static void
add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
{
  const int n = cie_table->num_entries;

  gdb_assert (n < 1
              || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);

  cie_table->entries
    = XRESIZEVEC (struct dwarf2_cie *, cie_table->entries, n + 1);
  cie_table->entries[n] = cie;
  cie_table->num_entries = n + 1;
}

static int
bsearch_fde_cmp (const void *key, const void *element)
{
  CORE_ADDR seek_pc = *(CORE_ADDR *) key;
  struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;

  if (seek_pc < fde->initial_location)
    return -1;
  if (seek_pc < fde->initial_location + fde->address_range)
    return 0;
  return 1;
}

/* Find the FDE for *PC.  Return a pointer to the FDE, and store the
   inital location associated with it into *PC.  */

static struct dwarf2_fde *
dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
{
  struct objfile *objfile;

  ALL_OBJFILES (objfile)
    {
      struct dwarf2_fde_table *fde_table;
      struct dwarf2_fde **p_fde;
      CORE_ADDR offset;
      CORE_ADDR seek_pc;

      fde_table = ((struct dwarf2_fde_table *)
		   objfile_data (objfile, dwarf2_frame_objfile_data));
      if (fde_table == NULL)
	{
	  dwarf2_build_frame_info (objfile);
	  fde_table = ((struct dwarf2_fde_table *)
		       objfile_data (objfile, dwarf2_frame_objfile_data));
	}
      gdb_assert (fde_table != NULL);

      if (fde_table->num_entries == 0)
	continue;

      gdb_assert (objfile->section_offsets);
      offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

      gdb_assert (fde_table->num_entries > 0);
      if (*pc < offset + fde_table->entries[0]->initial_location)
        continue;

      seek_pc = *pc - offset;
      p_fde = ((struct dwarf2_fde **)
	       bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
                        sizeof (fde_table->entries[0]), bsearch_fde_cmp));
      if (p_fde != NULL)
        {
          *pc = (*p_fde)->initial_location + offset;
	  if (out_offset)
	    *out_offset = offset;
          return *p_fde;
        }
    }
  return NULL;
}

/* Add a pointer to new FDE to the FDE_TABLE, allocating space for it.  */
static void
add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
{
  if (fde->address_range == 0)
    /* Discard useless FDEs.  */
    return;

  fde_table->num_entries += 1;
  fde_table->entries = XRESIZEVEC (struct dwarf2_fde *, fde_table->entries,
				   fde_table->num_entries);
  fde_table->entries[fde_table->num_entries - 1] = fde;
}

#define DW64_CIE_ID 0xffffffffffffffffULL

/* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
   or any of them.  */

enum eh_frame_type
{
  EH_CIE_TYPE_ID = 1 << 0,
  EH_FDE_TYPE_ID = 1 << 1,
  EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
};

static const gdb_byte *decode_frame_entry (struct comp_unit *unit,
					   const gdb_byte *start,
					   int eh_frame_p,
					   struct dwarf2_cie_table *cie_table,
					   struct dwarf2_fde_table *fde_table,
					   enum eh_frame_type entry_type);

/* Decode the next CIE or FDE, entry_type specifies the expected type.
   Return NULL if invalid input, otherwise the next byte to be processed.  */

static const gdb_byte *
decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
		      int eh_frame_p,
                      struct dwarf2_cie_table *cie_table,
                      struct dwarf2_fde_table *fde_table,
                      enum eh_frame_type entry_type)
{
  struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
  const gdb_byte *buf, *end;
  LONGEST length;
  unsigned int bytes_read;
  int dwarf64_p;
  ULONGEST cie_id;
  ULONGEST cie_pointer;
  int64_t sleb128;
  uint64_t uleb128;

  buf = start;
  length = read_initial_length (unit->abfd, buf, &bytes_read);
  buf += bytes_read;
  end = buf + length;

  /* Are we still within the section?  */
  if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
    return NULL;

  if (length == 0)
    return end;

  /* Distinguish between 32 and 64-bit encoded frame info.  */
  dwarf64_p = (bytes_read == 12);

  /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs.  */
  if (eh_frame_p)
    cie_id = 0;
  else if (dwarf64_p)
    cie_id = DW64_CIE_ID;
  else
    cie_id = DW_CIE_ID;

  if (dwarf64_p)
    {
      cie_pointer = read_8_bytes (unit->abfd, buf);
      buf += 8;
    }
  else
    {
      cie_pointer = read_4_bytes (unit->abfd, buf);
      buf += 4;
    }

  if (cie_pointer == cie_id)
    {
      /* This is a CIE.  */
      struct dwarf2_cie *cie;
      char *augmentation;
      unsigned int cie_version;

      /* Check that a CIE was expected.  */
      if ((entry_type & EH_CIE_TYPE_ID) == 0)
	error (_("Found a CIE when not expecting it."));

      /* Record the offset into the .debug_frame section of this CIE.  */
      cie_pointer = start - unit->dwarf_frame_buffer;

      /* Check whether we've already read it.  */
      if (find_cie (cie_table, cie_pointer))
	return end;

      cie = XOBNEW (&unit->objfile->objfile_obstack, struct dwarf2_cie);
      cie->initial_instructions = NULL;
      cie->cie_pointer = cie_pointer;

      /* The encoding for FDE's in a normal .debug_frame section
         depends on the target address size.  */
      cie->encoding = DW_EH_PE_absptr;

      /* We'll determine the final value later, but we need to
	 initialize it conservatively.  */
      cie->signal_frame = 0;

      /* Check version number.  */
      cie_version = read_1_byte (unit->abfd, buf);
      if (cie_version != 1 && cie_version != 3 && cie_version != 4)
	return NULL;
      cie->version = cie_version;
      buf += 1;

      /* Interpret the interesting bits of the augmentation.  */
      cie->augmentation = augmentation = (char *) buf;
      buf += (strlen (augmentation) + 1);

      /* Ignore armcc augmentations.  We only use them for quirks,
	 and that doesn't happen until later.  */
      if (startswith (augmentation, "armcc"))
	augmentation += strlen (augmentation);

      /* The GCC 2.x "eh" augmentation has a pointer immediately
         following the augmentation string, so it must be handled
         first.  */
      if (augmentation[0] == 'e' && augmentation[1] == 'h')
	{
	  /* Skip.  */
	  buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
	  augmentation += 2;
	}

      if (cie->version >= 4)
	{
	  /* FIXME: check that this is the same as from the CU header.  */
	  cie->addr_size = read_1_byte (unit->abfd, buf);
	  ++buf;
	  cie->segment_size = read_1_byte (unit->abfd, buf);
	  ++buf;
	}
      else
	{
	  cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
	  cie->segment_size = 0;
	}
      /* Address values in .eh_frame sections are defined to have the
	 target's pointer size.  Watchout: This breaks frame info for
	 targets with pointer size < address size, unless a .debug_frame
	 section exists as well.  */
      if (eh_frame_p)
	cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
      else
	cie->ptr_size = cie->addr_size;

      buf = gdb_read_uleb128 (buf, end, &uleb128);
      if (buf == NULL)
	return NULL;
      cie->code_alignment_factor = uleb128;

      buf = gdb_read_sleb128 (buf, end, &sleb128);
      if (buf == NULL)
	return NULL;
      cie->data_alignment_factor = sleb128;

      if (cie_version == 1)
	{
	  cie->return_address_register = read_1_byte (unit->abfd, buf);
	  ++buf;
	}
      else
	{
	  buf = gdb_read_uleb128 (buf, end, &uleb128);
	  if (buf == NULL)
	    return NULL;
	  cie->return_address_register = uleb128;
	}

      cie->return_address_register
	= dwarf2_frame_adjust_regnum (gdbarch,
				      cie->return_address_register,
				      eh_frame_p);

      cie->saw_z_augmentation = (*augmentation == 'z');
      if (cie->saw_z_augmentation)
	{
	  uint64_t length;

	  buf = gdb_read_uleb128 (buf, end, &length);
	  if (buf == NULL)
	    return NULL;
	  cie->initial_instructions = buf + length;
	  augmentation++;
	}

      while (*augmentation)
	{
	  /* "L" indicates a byte showing how the LSDA pointer is encoded.  */
	  if (*augmentation == 'L')
	    {
	      /* Skip.  */
	      buf++;
	      augmentation++;
	    }

	  /* "R" indicates a byte indicating how FDE addresses are encoded.  */
	  else if (*augmentation == 'R')
	    {
	      cie->encoding = *buf++;
	      augmentation++;
	    }

	  /* "P" indicates a personality routine in the CIE augmentation.  */
	  else if (*augmentation == 'P')
	    {
	      /* Skip.  Avoid indirection since we throw away the result.  */
	      gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
	      read_encoded_value (unit, encoding, cie->ptr_size,
				  buf, &bytes_read, 0);
	      buf += bytes_read;
	      augmentation++;
	    }

	  /* "S" indicates a signal frame, such that the return
	     address must not be decremented to locate the call frame
	     info for the previous frame; it might even be the first
	     instruction of a function, so decrementing it would take
	     us to a different function.  */
	  else if (*augmentation == 'S')
	    {
	      cie->signal_frame = 1;
	      augmentation++;
	    }

	  /* Otherwise we have an unknown augmentation.  Assume that either
	     there is no augmentation data, or we saw a 'z' prefix.  */
	  else
	    {
	      if (cie->initial_instructions)
		buf = cie->initial_instructions;
	      break;
	    }
	}

      cie->initial_instructions = buf;
      cie->end = end;
      cie->unit = unit;

      add_cie (cie_table, cie);
    }
  else
    {
      /* This is a FDE.  */
      struct dwarf2_fde *fde;
      CORE_ADDR addr;

      /* Check that an FDE was expected.  */
      if ((entry_type & EH_FDE_TYPE_ID) == 0)
	error (_("Found an FDE when not expecting it."));

      /* In an .eh_frame section, the CIE pointer is the delta between the
	 address within the FDE where the CIE pointer is stored and the
	 address of the CIE.  Convert it to an offset into the .eh_frame
	 section.  */
      if (eh_frame_p)
	{
	  cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
	  cie_pointer -= (dwarf64_p ? 8 : 4);
	}

      /* In either case, validate the result is still within the section.  */
      if (cie_pointer >= unit->dwarf_frame_size)
	return NULL;

      fde = XOBNEW (&unit->objfile->objfile_obstack, struct dwarf2_fde);
      fde->cie = find_cie (cie_table, cie_pointer);
      if (fde->cie == NULL)
	{
	  decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
			      eh_frame_p, cie_table, fde_table,
			      EH_CIE_TYPE_ID);
	  fde->cie = find_cie (cie_table, cie_pointer);
	}

      gdb_assert (fde->cie != NULL);

      addr = read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
				 buf, &bytes_read, 0);
      fde->initial_location = gdbarch_adjust_dwarf2_addr (gdbarch, addr);
      buf += bytes_read;

      fde->address_range =
	read_encoded_value (unit, fde->cie->encoding & 0x0f,
			    fde->cie->ptr_size, buf, &bytes_read, 0);
      addr = gdbarch_adjust_dwarf2_addr (gdbarch, addr + fde->address_range);
      fde->address_range = addr - fde->initial_location;
      buf += bytes_read;

      /* A 'z' augmentation in the CIE implies the presence of an
	 augmentation field in the FDE as well.  The only thing known
	 to be in here at present is the LSDA entry for EH.  So we
	 can skip the whole thing.  */
      if (fde->cie->saw_z_augmentation)
	{
	  uint64_t length;

	  buf = gdb_read_uleb128 (buf, end, &length);
	  if (buf == NULL)
	    return NULL;
	  buf += length;
	  if (buf > end)
	    return NULL;
	}

      fde->instructions = buf;
      fde->end = end;

      fde->eh_frame_p = eh_frame_p;

      add_fde (fde_table, fde);
    }

  return end;
}

/* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
   expect an FDE or a CIE.  */

static const gdb_byte *
decode_frame_entry (struct comp_unit *unit, const gdb_byte *start,
		    int eh_frame_p,
                    struct dwarf2_cie_table *cie_table,
                    struct dwarf2_fde_table *fde_table,
                    enum eh_frame_type entry_type)
{
  enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
  const gdb_byte *ret;
  ptrdiff_t start_offset;

  while (1)
    {
      ret = decode_frame_entry_1 (unit, start, eh_frame_p,
				  cie_table, fde_table, entry_type);
      if (ret != NULL)
	break;

      /* We have corrupt input data of some form.  */

      /* ??? Try, weakly, to work around compiler/assembler/linker bugs
	 and mismatches wrt padding and alignment of debug sections.  */
      /* Note that there is no requirement in the standard for any
	 alignment at all in the frame unwind sections.  Testing for
	 alignment before trying to interpret data would be incorrect.

	 However, GCC traditionally arranged for frame sections to be
	 sized such that the FDE length and CIE fields happen to be
	 aligned (in theory, for performance).  This, unfortunately,
	 was done with .align directives, which had the side effect of
	 forcing the section to be aligned by the linker.

	 This becomes a problem when you have some other producer that
	 creates frame sections that are not as strictly aligned.  That
	 produces a hole in the frame info that gets filled by the 
	 linker with zeros.

	 The GCC behaviour is arguably a bug, but it's effectively now
	 part of the ABI, so we're now stuck with it, at least at the
	 object file level.  A smart linker may decide, in the process
	 of compressing duplicate CIE information, that it can rewrite
	 the entire output section without this extra padding.  */

      start_offset = start - unit->dwarf_frame_buffer;
      if (workaround < ALIGN4 && (start_offset & 3) != 0)
	{
	  start += 4 - (start_offset & 3);
	  workaround = ALIGN4;
	  continue;
	}
      if (workaround < ALIGN8 && (start_offset & 7) != 0)
	{
	  start += 8 - (start_offset & 7);
	  workaround = ALIGN8;
	  continue;
	}

      /* Nothing left to try.  Arrange to return as if we've consumed
	 the entire input section.  Hopefully we'll get valid info from
	 the other of .debug_frame/.eh_frame.  */
      workaround = FAIL;
      ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
      break;
    }

  switch (workaround)
    {
    case NONE:
      break;

    case ALIGN4:
      complaint (_("\
Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
		 unit->dwarf_frame_section->owner->filename,
		 unit->dwarf_frame_section->name);
      break;

    case ALIGN8:
      complaint (_("\
Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
		 unit->dwarf_frame_section->owner->filename,
		 unit->dwarf_frame_section->name);
      break;

    default:
      complaint (_("Corrupt data in %s:%s"),
		 unit->dwarf_frame_section->owner->filename,
		 unit->dwarf_frame_section->name);
      break;
    }

  return ret;
}

static int
qsort_fde_cmp (const void *a, const void *b)
{
  struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
  struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;

  if (aa->initial_location == bb->initial_location)
    {
      if (aa->address_range != bb->address_range
          && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
        /* Linker bug, e.g. gold/10400.
           Work around it by keeping stable sort order.  */
        return (a < b) ? -1 : 1;
      else
        /* Put eh_frame entries after debug_frame ones.  */
        return aa->eh_frame_p - bb->eh_frame_p;
    }

  return (aa->initial_location < bb->initial_location) ? -1 : 1;
}

void
dwarf2_build_frame_info (struct objfile *objfile)
{
  struct comp_unit *unit;
  const gdb_byte *frame_ptr;
  struct dwarf2_cie_table cie_table;
  struct dwarf2_fde_table fde_table;
  struct dwarf2_fde_table *fde_table2;

  cie_table.num_entries = 0;
  cie_table.entries = NULL;

  fde_table.num_entries = 0;
  fde_table.entries = NULL;

  /* Build a minimal decoding of the DWARF2 compilation unit.  */
  unit = XOBNEW (&objfile->objfile_obstack, comp_unit);
  unit->abfd = objfile->obfd;
  unit->objfile = objfile;
  unit->dbase = 0;
  unit->tbase = 0;

  if (objfile->separate_debug_objfile_backlink == NULL)
    {
      /* Do not read .eh_frame from separate file as they must be also
         present in the main file.  */
      dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
                               &unit->dwarf_frame_section,
                               &unit->dwarf_frame_buffer,
                               &unit->dwarf_frame_size);
      if (unit->dwarf_frame_size)
        {
          asection *got, *txt;

          /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
             that is used for the i386/amd64 target, which currently is
             the only target in GCC that supports/uses the
             DW_EH_PE_datarel encoding.  */
          got = bfd_get_section_by_name (unit->abfd, ".got");
          if (got)
            unit->dbase = got->vma;

          /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
             so far.  */
          txt = bfd_get_section_by_name (unit->abfd, ".text");
          if (txt)
            unit->tbase = txt->vma;

	  TRY
	    {
	      frame_ptr = unit->dwarf_frame_buffer;
	      while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
		frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
						&cie_table, &fde_table,
						EH_CIE_OR_FDE_TYPE_ID);
	    }

	  CATCH (e, RETURN_MASK_ERROR)
	    {
	      warning (_("skipping .eh_frame info of %s: %s"),
		       objfile_name (objfile), e.message);

	      if (fde_table.num_entries != 0)
		{
                  xfree (fde_table.entries);
		  fde_table.entries = NULL;
		  fde_table.num_entries = 0;
		}
	      /* The cie_table is discarded by the next if.  */
	    }
	  END_CATCH

          if (cie_table.num_entries != 0)
            {
              /* Reinit cie_table: debug_frame has different CIEs.  */
              xfree (cie_table.entries);
              cie_table.num_entries = 0;
              cie_table.entries = NULL;
            }
        }
    }

  dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
                           &unit->dwarf_frame_section,
                           &unit->dwarf_frame_buffer,
                           &unit->dwarf_frame_size);
  if (unit->dwarf_frame_size)
    {
      int num_old_fde_entries = fde_table.num_entries;

      TRY
	{
	  frame_ptr = unit->dwarf_frame_buffer;
	  while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
	    frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
					    &cie_table, &fde_table,
					    EH_CIE_OR_FDE_TYPE_ID);
	}
      CATCH (e, RETURN_MASK_ERROR)
	{
	  warning (_("skipping .debug_frame info of %s: %s"),
		   objfile_name (objfile), e.message);

	  if (fde_table.num_entries != 0)
	    {
	      fde_table.num_entries = num_old_fde_entries;
	      if (num_old_fde_entries == 0)
		{
		  xfree (fde_table.entries);
		  fde_table.entries = NULL;
		}
	      else
		{
		  fde_table.entries
		    = XRESIZEVEC (struct dwarf2_fde *, fde_table.entries,
				  fde_table.num_entries);
		}
	    }
	  fde_table.num_entries = num_old_fde_entries;
	  /* The cie_table is discarded by the next if.  */
	}
      END_CATCH
    }

  /* Discard the cie_table, it is no longer needed.  */
  if (cie_table.num_entries != 0)
    {
      xfree (cie_table.entries);
      cie_table.entries = NULL;   /* Paranoia.  */
      cie_table.num_entries = 0;  /* Paranoia.  */
    }

  /* Copy fde_table to obstack: it is needed at runtime.  */
  fde_table2 = XOBNEW (&objfile->objfile_obstack, struct dwarf2_fde_table);

  if (fde_table.num_entries == 0)
    {
      fde_table2->entries = NULL;
      fde_table2->num_entries = 0;
    }
  else
    {
      struct dwarf2_fde *fde_prev = NULL;
      struct dwarf2_fde *first_non_zero_fde = NULL;
      int i;

      /* Prepare FDE table for lookups.  */
      qsort (fde_table.entries, fde_table.num_entries,
             sizeof (fde_table.entries[0]), qsort_fde_cmp);

      /* Check for leftovers from --gc-sections.  The GNU linker sets
	 the relevant symbols to zero, but doesn't zero the FDE *end*
	 ranges because there's no relocation there.  It's (offset,
	 length), not (start, end).  On targets where address zero is
	 just another valid address this can be a problem, since the
	 FDEs appear to be non-empty in the output --- we could pick
	 out the wrong FDE.  To work around this, when overlaps are
	 detected, we prefer FDEs that do not start at zero.

	 Start by finding the first FDE with non-zero start.  Below
	 we'll discard all FDEs that start at zero and overlap this
	 one.  */
      for (i = 0; i < fde_table.num_entries; i++)
	{
	  struct dwarf2_fde *fde = fde_table.entries[i];

	  if (fde->initial_location != 0)
	    {
	      first_non_zero_fde = fde;
	      break;
	    }
	}

      /* Since we'll be doing bsearch, squeeze out identical (except
	 for eh_frame_p) fde entries so bsearch result is predictable.
	 Also discard leftovers from --gc-sections.  */
      fde_table2->num_entries = 0;
      for (i = 0; i < fde_table.num_entries; i++)
	{
	  struct dwarf2_fde *fde = fde_table.entries[i];

	  if (fde->initial_location == 0
	      && first_non_zero_fde != NULL
	      && (first_non_zero_fde->initial_location
		  < fde->initial_location + fde->address_range))
	    continue;

	  if (fde_prev != NULL
	      && fde_prev->initial_location == fde->initial_location)
	    continue;

	  obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
			sizeof (fde_table.entries[0]));
	  ++fde_table2->num_entries;
	  fde_prev = fde;
	}
      fde_table2->entries
	= (struct dwarf2_fde **) obstack_finish (&objfile->objfile_obstack);

      /* Discard the original fde_table.  */
      xfree (fde_table.entries);
    }

  set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
}

/* Handle 'maintenance show dwarf unwinders'.  */

static void
show_dwarf_unwinders_enabled_p (struct ui_file *file, int from_tty,
				struct cmd_list_element *c,
				const char *value)
{
  fprintf_filtered (file,
		    _("The DWARF stack unwinders are currently %s.\n"),
		    value);
}

void
_initialize_dwarf2_frame (void)
{
  dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
  dwarf2_frame_objfile_data = register_objfile_data ();

  add_setshow_boolean_cmd ("unwinders", class_obscure,
			   &dwarf2_frame_unwinders_enabled_p , _("\
Set whether the DWARF stack frame unwinders are used."), _("\
Show whether the DWARF stack frame unwinders are used."), _("\
When enabled the DWARF stack frame unwinders can be used for architectures\n\
that support the DWARF unwinders.  Enabling the DWARF unwinders for an\n\
architecture that doesn't support them will have no effect."),
			   NULL,
			   show_dwarf_unwinders_enabled_p,
			   &set_dwarf_cmdlist,
			   &show_dwarf_cmdlist);

#if GDB_SELF_TEST
  selftests::register_test_foreach_arch ("execute_cfa_program",
					 selftests::execute_cfa_program_test);
#endif
}