aboutsummaryrefslogtreecommitdiff
path: root/gdb/rs6000-aix-tdep.c
blob: 64d14d72484d1a7dca9a667f02cc6923ff135f4f (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
/* Native support code for PPC AIX, for GDB the GNU debugger.

   Copyright (C) 2006-2023 Free Software Foundation, Inc.

   Free Software Foundation, Inc.

   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 "osabi.h"
#include "regcache.h"
#include "regset.h"
#include "gdbtypes.h"
#include "gdbcore.h"
#include "target.h"
#include "value.h"
#include "infcall.h"
#include "objfiles.h"
#include "breakpoint.h"
#include "ppc-tdep.h"
#include "rs6000-aix-tdep.h"
#include "xcoffread.h"
#include "solib.h"
#include "solib-aix.h"
#include "target-float.h"
#include "gdbsupport/xml-utils.h"
#include "trad-frame.h"
#include "frame-unwind.h"

/* If the kernel has to deliver a signal, it pushes a sigcontext
   structure on the stack and then calls the signal handler, passing
   the address of the sigcontext in an argument register.  Usually
   the signal handler doesn't save this register, so we have to
   access the sigcontext structure via an offset from the signal handler
   frame.
   The following constants were determined by experimentation on AIX 3.2.

   sigcontext structure have the mstsave saved under the
   sc_jmpbuf.jmp_context. STKMIN(minimum stack size) is 56 for 32-bit
   processes, and iar offset under sc_jmpbuf.jmp_context is 40.
   ie offsetof(struct sigcontext, sc_jmpbuf.jmp_context.iar).
   so PC offset in this case is STKMIN+iar offset, which is 96. */

#define SIG_FRAME_PC_OFFSET 96
#define SIG_FRAME_LR_OFFSET 108
/* STKMIN+grp1 offset, which is 56+228=284 */
#define SIG_FRAME_FP_OFFSET 284

/* 64 bit process.
   STKMIN64  is 112 and iar offset is 312. So 112+312=424 */
#define SIG_FRAME_LR_OFFSET64 424
/* STKMIN64+grp1 offset. 112+56=168 */
#define SIG_FRAME_FP_OFFSET64 168

/* Minimum possible text address in AIX.  */
#define AIX_TEXT_SEGMENT_BASE 0x10000000

struct rs6000_aix_reg_vrreg_offset
{
  int vr0_offset;
  int vscr_offset;
  int vrsave_offset;
};

static struct rs6000_aix_reg_vrreg_offset rs6000_aix_vrreg_offset =
{
   /* AltiVec registers.  */
  32, /* vr0_offset */
  544, /* vscr_offset. */
  560 /* vrsave_offset */
};

static int
rs6000_aix_get_vrreg_offset (ppc_gdbarch_tdep *tdep,
  const struct rs6000_aix_reg_vrreg_offset *offsets,
  int regnum)
{
  if (regnum >= tdep->ppc_vr0_regnum &&
  regnum < tdep->ppc_vr0_regnum + ppc_num_vrs)
    return offsets->vr0_offset + (regnum - tdep->ppc_vr0_regnum) * 16;

  if (regnum == tdep->ppc_vrsave_regnum - 1)
    return offsets->vscr_offset;

  if (regnum == tdep->ppc_vrsave_regnum)
    return offsets->vrsave_offset;

  return -1;
}

static void
rs6000_aix_supply_vrregset (const struct regset *regset, struct regcache *regcache,
			    int regnum, const void *vrregs, size_t len)
{
  struct gdbarch *gdbarch = regcache->arch ();
  const struct rs6000_aix_reg_vrreg_offset  *offsets;
  size_t offset;
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  if (!(tdep->ppc_vr0_regnum >= 0  && tdep->ppc_vrsave_regnum >= 0))
    return;

  offsets = (const struct rs6000_aix_reg_vrreg_offset *) regset->regmap;
  if (regnum == -1)
    {
      int i;

      for (i = tdep->ppc_vr0_regnum, offset = offsets->vr0_offset;
			   i < tdep->ppc_vr0_regnum + ppc_num_vrs;
						i++, offset += 16)
	ppc_supply_reg (regcache, i, (const gdb_byte *) vrregs, offset, 16);

      ppc_supply_reg (regcache, (tdep->ppc_vrsave_regnum - 1),
	  (const gdb_byte *) vrregs, offsets->vscr_offset, 4);

      ppc_supply_reg (regcache, tdep->ppc_vrsave_regnum,
	(const gdb_byte *) vrregs, offsets->vrsave_offset, 4);

      return;
    }
  offset = rs6000_aix_get_vrreg_offset (tdep, offsets, regnum);
  if (regnum != tdep->ppc_vrsave_regnum &&
      regnum != tdep->ppc_vrsave_regnum - 1)
    ppc_supply_reg (regcache, regnum, (const gdb_byte *) vrregs, offset, 16);
  else
    ppc_supply_reg (regcache, regnum,
     (const gdb_byte *) vrregs, offset, 4);

}

static void
rs6000_aix_supply_vsxregset (const struct regset *regset, struct regcache *regcache,
			     int regnum, const void *vsxregs, size_t len)
{
  struct gdbarch *gdbarch = regcache->arch ();
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  if (!(tdep->ppc_vsr0_regnum >= 0))
    return;

  if (regnum == -1)
    {
      int i, offset = 0;

      for (i = tdep->ppc_vsr0_upper_regnum; i < tdep->ppc_vsr0_upper_regnum 
						     + 32; i++, offset += 8)
	ppc_supply_reg (regcache, i, (const gdb_byte *) vsxregs, offset, 8);

      return;
    }
  else
    ppc_supply_reg (regcache, regnum, (const gdb_byte *) vsxregs, 0, 8);
}

static void
rs6000_aix_collect_vsxregset (const struct regset *regset,
			      const struct regcache *regcache,
			      int regnum, void *vsxregs, size_t len)
{
  struct gdbarch *gdbarch = regcache->arch ();
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  if (!(tdep->ppc_vsr0_regnum >= 0))
    return;

  if (regnum == -1)
    {
      int i;
      int offset = 0;
      for (i = tdep->ppc_vsr0_upper_regnum; i < tdep->ppc_vsr0_upper_regnum
						     + 32; i++, offset += 8)
	ppc_collect_reg (regcache, i, (gdb_byte *) vsxregs, offset, 8);

      return;
    }
  else
    ppc_collect_reg (regcache, regnum, (gdb_byte *) vsxregs, 0, 8);
}

static void
rs6000_aix_collect_vrregset (const struct regset *regset,
			     const struct regcache *regcache,
			     int regnum, void *vrregs, size_t len)
{
  struct gdbarch *gdbarch = regcache->arch ();
  const struct rs6000_aix_reg_vrreg_offset *offsets;
  size_t offset;

  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  if (!(tdep->ppc_vr0_regnum >= 0 && tdep->ppc_vrsave_regnum >= 0))
    return;

  offsets = (const struct rs6000_aix_reg_vrreg_offset *) regset->regmap;
  if (regnum == -1)
    {
      int i;

      for (i = tdep->ppc_vr0_regnum, offset = offsets->vr0_offset; i <
		tdep->ppc_vr0_regnum + ppc_num_vrs; i++, offset += 16)
	ppc_collect_reg (regcache, i, (gdb_byte *) vrregs, offset, 16);

      ppc_collect_reg (regcache, (tdep->ppc_vrsave_regnum - 1),
		 (gdb_byte *) vrregs, offsets->vscr_offset, 4);

      ppc_collect_reg (regcache, tdep->ppc_vrsave_regnum,
	 (gdb_byte *) vrregs, offsets->vrsave_offset, 4);

      return;
    }

  offset = rs6000_aix_get_vrreg_offset (tdep, offsets, regnum);
  if (regnum != tdep->ppc_vrsave_regnum
      && regnum != tdep->ppc_vrsave_regnum - 1)
    ppc_collect_reg (regcache, regnum, (gdb_byte *) vrregs, offset, 16);
  else
    ppc_collect_reg (regcache, regnum,
		     (gdb_byte *) vrregs, offset, 4);
}

static const struct regset rs6000_aix_vrregset = {
  &rs6000_aix_vrreg_offset,
  rs6000_aix_supply_vrregset,
  rs6000_aix_collect_vrregset
};

static const struct regset rs6000_aix_vsxregset = {
  &rs6000_aix_vrreg_offset,
  rs6000_aix_supply_vsxregset,
  rs6000_aix_collect_vsxregset
};

static struct trad_frame_cache *
aix_sighandle_frame_cache (frame_info_ptr this_frame,
			   void **this_cache)
{
  LONGEST backchain;
  CORE_ADDR base, base_orig, func;
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  struct trad_frame_cache *this_trad_cache;

  if ((*this_cache) != NULL)
    return (struct trad_frame_cache *) (*this_cache);

  this_trad_cache = trad_frame_cache_zalloc (this_frame);
  (*this_cache) = this_trad_cache;

  base = get_frame_register_unsigned (this_frame,
				      gdbarch_sp_regnum (gdbarch));
  base_orig = base;

  if (tdep->wordsize == 4)
    {
      func = read_memory_unsigned_integer (base_orig +
					   SIG_FRAME_PC_OFFSET + 8,
					   tdep->wordsize, byte_order);
      safe_read_memory_integer (base_orig + SIG_FRAME_FP_OFFSET + 8,
				tdep->wordsize, byte_order, &backchain);
      base = (CORE_ADDR)backchain;
    }
  else
    {
      func = read_memory_unsigned_integer (base_orig +
					   SIG_FRAME_LR_OFFSET64,
					   tdep->wordsize, byte_order);
      safe_read_memory_integer (base_orig + SIG_FRAME_FP_OFFSET64,
				tdep->wordsize, byte_order, &backchain);
      base = (CORE_ADDR)backchain;
    }

  trad_frame_set_reg_value (this_trad_cache, gdbarch_pc_regnum (gdbarch), func);
  trad_frame_set_reg_value (this_trad_cache, gdbarch_sp_regnum (gdbarch), base);

  if (tdep->wordsize == 4)
    trad_frame_set_reg_addr (this_trad_cache, tdep->ppc_lr_regnum,
			     base_orig + 0x38 + 52 + 8);
  else
    trad_frame_set_reg_addr (this_trad_cache, tdep->ppc_lr_regnum,
			     base_orig + 0x70 + 320);

  trad_frame_set_id (this_trad_cache, frame_id_build (base, func));
  trad_frame_set_this_base (this_trad_cache, base);

  return this_trad_cache;
}

static void
aix_sighandle_frame_this_id (frame_info_ptr this_frame,
			     void **this_prologue_cache,
			     struct frame_id *this_id)
{
  struct trad_frame_cache *this_trad_cache
    = aix_sighandle_frame_cache (this_frame, this_prologue_cache);
  trad_frame_get_id (this_trad_cache, this_id);
}

static struct value *
aix_sighandle_frame_prev_register (frame_info_ptr this_frame,
				   void **this_prologue_cache, int regnum)
{
  struct trad_frame_cache *this_trad_cache
    = aix_sighandle_frame_cache (this_frame, this_prologue_cache);
  return trad_frame_get_register (this_trad_cache, this_frame, regnum);
}

static int
aix_sighandle_frame_sniffer (const struct frame_unwind *self,
			     frame_info_ptr this_frame,
			     void **this_prologue_cache)
{
  CORE_ADDR pc = get_frame_pc (this_frame);
  if (pc && pc < AIX_TEXT_SEGMENT_BASE)
    return 1;

  return 0;
}

/* AIX signal handler frame unwinder */

static const struct frame_unwind aix_sighandle_frame_unwind = {
  "rs6000 aix sighandle",
  SIGTRAMP_FRAME,
  default_frame_unwind_stop_reason,
  aix_sighandle_frame_this_id,
  aix_sighandle_frame_prev_register,
  NULL,
  aix_sighandle_frame_sniffer
};

/* Core file support.  */

static struct ppc_reg_offsets rs6000_aix32_reg_offsets =
{
  /* General-purpose registers.  */
  208, /* r0_offset */
  4,  /* gpr_size */
  4,  /* xr_size */
  24, /* pc_offset */
  28, /* ps_offset */
  32, /* cr_offset */
  36, /* lr_offset */
  40, /* ctr_offset */
  44, /* xer_offset */
  48, /* mq_offset */

  /* Floating-point registers.  */
  336, /* f0_offset */
  56, /* fpscr_offset */
  4  /* fpscr_size */
};

static struct ppc_reg_offsets rs6000_aix64_reg_offsets =
{
  /* General-purpose registers.  */
  0, /* r0_offset */
  8,  /* gpr_size */
  4,  /* xr_size */
  264, /* pc_offset */
  256, /* ps_offset */
  288, /* cr_offset */
  272, /* lr_offset */
  280, /* ctr_offset */
  292, /* xer_offset */
  -1, /* mq_offset */

  /* Floating-point registers.  */
  312, /* f0_offset */
  296, /* fpscr_offset */
  4  /* fpscr_size */
};


/* Supply register REGNUM in the general-purpose register set REGSET
   from the buffer specified by GREGS and LEN to register cache
   REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */

static void
rs6000_aix_supply_regset (const struct regset *regset,
			  struct regcache *regcache, int regnum,
			  const void *gregs, size_t len)
{
  ppc_supply_gregset (regset, regcache, regnum, gregs, len);
  ppc_supply_fpregset (regset, regcache, regnum, gregs, len);
}

/* Collect register REGNUM in the general-purpose register set
   REGSET, from register cache REGCACHE into the buffer specified by
   GREGS and LEN.  If REGNUM is -1, do this for all registers in
   REGSET.  */

static void
rs6000_aix_collect_regset (const struct regset *regset,
			   const struct regcache *regcache, int regnum,
			   void *gregs, size_t len)
{
  ppc_collect_gregset (regset, regcache, regnum, gregs, len);
  ppc_collect_fpregset (regset, regcache, regnum, gregs, len);
}

/* AIX register set.  */

static const struct regset rs6000_aix32_regset =
{
  &rs6000_aix32_reg_offsets,
  rs6000_aix_supply_regset,
  rs6000_aix_collect_regset,
};

static const struct regset rs6000_aix64_regset =
{
  &rs6000_aix64_reg_offsets,
  rs6000_aix_supply_regset,
  rs6000_aix_collect_regset,
};

/* Iterate over core file register note sections.  */

static void
rs6000_aix_iterate_over_regset_sections (struct gdbarch *gdbarch,
					 iterate_over_regset_sections_cb *cb,
					 void *cb_data,
					 const struct regcache *regcache)
{
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  int have_altivec = tdep->ppc_vr0_regnum != -1;
  int have_vsx = tdep->ppc_vsr0_upper_regnum != -1;

  if (tdep->wordsize == 4)
    cb (".reg", 592, 592, &rs6000_aix32_regset, NULL, cb_data);
  else
    cb (".reg", 576, 576, &rs6000_aix64_regset, NULL, cb_data);

  if (have_altivec)
   cb (".aix-vmx", 560, 560, &rs6000_aix_vrregset, "AIX altivec", cb_data);

  if (have_vsx)
   cb (".aix-vsx", 256, 256, &rs6000_aix_vsxregset, "AIX vsx", cb_data);

}

/* Read core file description for AIX.  */

static const struct target_desc *
ppc_aix_core_read_description (struct gdbarch *gdbarch,
			       struct target_ops *target,
			       bfd *abfd)
{
  asection *altivec = bfd_get_section_by_name (abfd, ".aix-vmx");
  asection *vsx = bfd_get_section_by_name (abfd, ".aix-vsx");
  asection *section = bfd_get_section_by_name (abfd, ".reg");
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);

  if (!section)
    return NULL;

  int arch64 = 0;
  if (tdep->wordsize == 8)
    arch64 = 1;

  if (vsx && arch64)
    return tdesc_powerpc_vsx64;
  else if (vsx && !arch64)
    return tdesc_powerpc_vsx32;
  else if (altivec && arch64)
    return tdesc_powerpc_altivec64;
  else if (altivec && !arch64)
    return tdesc_powerpc_altivec32;

  return NULL;
}

/* Pass the arguments in either registers, or in the stack.  In RS/6000,
   the first eight words of the argument list (that might be less than
   eight parameters if some parameters occupy more than one word) are
   passed in r3..r10 registers.  Float and double parameters are
   passed in fpr's, in addition to that.  Rest of the parameters if any
   are passed in user stack.  There might be cases in which half of the
   parameter is copied into registers, the other half is pushed into
   stack.

   Stack must be aligned on 64-bit boundaries when synthesizing
   function calls.

   If the function is returning a structure, then the return address is passed
   in r3, then the first 7 words of the parameters can be passed in registers,
   starting from r4.  */

static CORE_ADDR
rs6000_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
			struct regcache *regcache, CORE_ADDR bp_addr,
			int nargs, struct value **args, CORE_ADDR sp,
			function_call_return_method return_method,
			CORE_ADDR struct_addr)
{
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  int ii;
  int len = 0;
  int argno;			/* current argument number */
  int argbytes;			/* current argument byte */
  gdb_byte tmp_buffer[50];
  int f_argno = 0;		/* current floating point argno */
  int wordsize = tdep->wordsize;
  CORE_ADDR func_addr = find_function_addr (function, NULL);

  struct value *arg = 0;
  struct type *type;

  ULONGEST saved_sp;

  /* The calling convention this function implements assumes the
     processor has floating-point registers.  We shouldn't be using it
     on PPC variants that lack them.  */
  gdb_assert (ppc_floating_point_unit_p (gdbarch));

  /* The first eight words of ther arguments are passed in registers.
     Copy them appropriately.  */
  ii = 0;

  /* If the function is returning a `struct', then the first word
     (which will be passed in r3) is used for struct return address.
     In that case we should advance one word and start from r4
     register to copy parameters.  */
  if (return_method == return_method_struct)
    {
      regcache_raw_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
				   struct_addr);
      ii++;
    }

/* effectively indirect call... gcc does...

   return_val example( float, int);

   eabi: 
   float in fp0, int in r3
   offset of stack on overflow 8/16
   for varargs, must go by type.
   power open:
   float in r3&r4, int in r5
   offset of stack on overflow different 
   both: 
   return in r3 or f0.  If no float, must study how gcc emulates floats;
   pay attention to arg promotion.
   User may have to cast\args to handle promotion correctly 
   since gdb won't know if prototype supplied or not.  */

  for (argno = 0, argbytes = 0; argno < nargs && ii < 8; ++ii)
    {
      int reg_size = register_size (gdbarch, ii + 3);

      arg = args[argno];
      type = check_typedef (arg->type ());
      len = type->length ();

      if (type->code () == TYPE_CODE_FLT)
	{
	  /* Floating point arguments are passed in fpr's, as well as gpr's.
	     There are 13 fpr's reserved for passing parameters.  At this point
	     there is no way we would run out of them.

	     Always store the floating point value using the register's
	     floating-point format.  */
	  const int fp_regnum = tdep->ppc_fp0_regnum + 1 + f_argno;
	  gdb_byte reg_val[PPC_MAX_REGISTER_SIZE];
	  struct type *reg_type = register_type (gdbarch, fp_regnum);

	  gdb_assert (len <= 8);

	  target_float_convert (arg->contents ().data (), type, reg_val,
				reg_type);
	  regcache->cooked_write (fp_regnum, reg_val);
	  ++f_argno;
	}

      if (len > reg_size)
	{

	  /* Argument takes more than one register.  */
	  while (argbytes < len)
	    {
	      gdb_byte word[PPC_MAX_REGISTER_SIZE];
	      memset (word, 0, reg_size);
	      memcpy (word,
		      ((char *) arg->contents ().data ()) + argbytes,
		      (len - argbytes) > reg_size
			? reg_size : len - argbytes);
	      regcache->cooked_write (tdep->ppc_gp0_regnum + 3 + ii, word);
	      ++ii, argbytes += reg_size;

	      if (ii >= 8)
		goto ran_out_of_registers_for_arguments;
	    }
	  argbytes = 0;
	  --ii;
	}
      else
	{
	  /* Argument can fit in one register.  No problem.  */
	  gdb_byte word[PPC_MAX_REGISTER_SIZE];

	  memset (word, 0, reg_size);
	  if (type->code () == TYPE_CODE_INT
	     || type->code () == TYPE_CODE_ENUM
	     || type->code () == TYPE_CODE_BOOL
	     || type->code () == TYPE_CODE_CHAR)
	    /* Sign or zero extend the "int" into a "word".  */
	    store_unsigned_integer (word, reg_size, byte_order,
				    unpack_long (type, arg->contents ().data ()));
	  else
	    memcpy (word, arg->contents ().data (), len);
	  regcache->cooked_write (tdep->ppc_gp0_regnum + 3 +ii, word);
	}
      ++argno;
    }

ran_out_of_registers_for_arguments:

  regcache_cooked_read_unsigned (regcache,
				 gdbarch_sp_regnum (gdbarch),
				 &saved_sp);

  /* Location for 8 parameters are always reserved.  */
  sp -= wordsize * 8;

  /* Another six words for back chain, TOC register, link register, etc.  */
  sp -= wordsize * 6;

  /* Stack pointer must be quadword aligned.  */
  sp &= -16;

  /* If there are more arguments, allocate space for them in 
     the stack, then push them starting from the ninth one.  */

  if ((argno < nargs) || argbytes)
    {
      int space = 0, jj;

      if (argbytes)
	{
	  space += ((len - argbytes + wordsize -1) & -wordsize);
	  jj = argno + 1;
	}
      else
	jj = argno;

      for (; jj < nargs; ++jj)
	{
	  struct value *val = args[jj];
	  space += ((val->type ()->length () + wordsize -1) & -wordsize);
	}

      /* Add location required for the rest of the parameters.  */
      space = (space + 15) & -16;
      sp -= space;

      /* This is another instance we need to be concerned about
	 securing our stack space.  If we write anything underneath %sp
	 (r1), we might conflict with the kernel who thinks he is free
	 to use this area.  So, update %sp first before doing anything
	 else.  */

      regcache_raw_write_signed (regcache,
				 gdbarch_sp_regnum (gdbarch), sp);

      /* If the last argument copied into the registers didn't fit there 
	 completely, push the rest of it into stack.  */

      if (argbytes)
	{
	  write_memory (sp + 6 * wordsize + (ii * wordsize),
			arg->contents ().data () + argbytes,
			len - argbytes);
	  ++argno;
	  ii += ((len - argbytes + wordsize - 1) & -wordsize) / wordsize;
	}

      /* Push the rest of the arguments into stack.  */
      for (; argno < nargs; ++argno)
	{

	  arg = args[argno];
	  type = check_typedef (arg->type ());
	  len = type->length ();


	  /* Float types should be passed in fpr's, as well as in the
	     stack.  */
	  if (type->code () == TYPE_CODE_FLT && f_argno < 13)
	    {

	      gdb_assert (len <= 8);

	      regcache->cooked_write (tdep->ppc_fp0_regnum + 1 + f_argno,
				      arg->contents ().data ());
	      ++f_argno;
	    }

	  if (type->code () == TYPE_CODE_INT
	     || type->code () == TYPE_CODE_ENUM
	     || type->code () == TYPE_CODE_BOOL
	     || type->code () == TYPE_CODE_CHAR )
	    {
	      gdb_byte word[PPC_MAX_REGISTER_SIZE];
	      memset (word, 0, PPC_MAX_REGISTER_SIZE);
	      store_unsigned_integer (word, tdep->wordsize, byte_order,
				      unpack_long (type, arg->contents ().data ()));
	      write_memory (sp + 6 * wordsize + (ii * wordsize), word, PPC_MAX_REGISTER_SIZE);
	    }
	  else
	    write_memory (sp + 6 * wordsize + (ii * wordsize), arg->contents ().data (), len);
	  ii += ((len + wordsize -1) & -wordsize) / wordsize;
	}
    }

  /* Set the stack pointer.  According to the ABI, the SP is meant to
     be set _before_ the corresponding stack space is used.  On AIX,
     this even applies when the target has been completely stopped!
     Not doing this can lead to conflicts with the kernel which thinks
     that it still has control over this not-yet-allocated stack
     region.  */
  regcache_raw_write_signed (regcache, gdbarch_sp_regnum (gdbarch), sp);

  /* Set back chain properly.  */
  store_unsigned_integer (tmp_buffer, wordsize, byte_order, saved_sp);
  write_memory (sp, tmp_buffer, wordsize);

  /* Point the inferior function call's return address at the dummy's
     breakpoint.  */
  regcache_raw_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);

  /* Set the TOC register value.  */
  regcache_raw_write_signed (regcache, tdep->ppc_toc_regnum,
			     solib_aix_get_toc_value (func_addr));

  target_store_registers (regcache, -1);
  return sp;
}

static enum return_value_convention
rs6000_return_value (struct gdbarch *gdbarch, struct value *function,
		     struct type *valtype, struct regcache *regcache,
		     gdb_byte *readbuf, const gdb_byte *writebuf)
{
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  /* The calling convention this function implements assumes the
     processor has floating-point registers.  We shouldn't be using it
     on PowerPC variants that lack them.  */
  gdb_assert (ppc_floating_point_unit_p (gdbarch));

  /* AltiVec extension: Functions that declare a vector data type as a
     return value place that return value in VR2.  */
  if (valtype->code () == TYPE_CODE_ARRAY && valtype->is_vector ()
      && valtype->length () == 16)
    {
      if (readbuf)
	regcache->cooked_read (tdep->ppc_vr0_regnum + 2, readbuf);
      if (writebuf)
	regcache->cooked_write (tdep->ppc_vr0_regnum + 2, writebuf);

      return RETURN_VALUE_REGISTER_CONVENTION;
    }

  /* If the called subprogram returns an aggregate, there exists an
     implicit first argument, whose value is the address of a caller-
     allocated buffer into which the callee is assumed to store its
     return value.  All explicit parameters are appropriately
     relabeled.  */
  if (valtype->code () == TYPE_CODE_STRUCT
      || valtype->code () == TYPE_CODE_UNION
      || valtype->code () == TYPE_CODE_ARRAY)
    return RETURN_VALUE_STRUCT_CONVENTION;

  /* Scalar floating-point values are returned in FPR1 for float or
     double, and in FPR1:FPR2 for quadword precision.  Fortran
     complex*8 and complex*16 are returned in FPR1:FPR2, and
     complex*32 is returned in FPR1:FPR4.  */
  if (valtype->code () == TYPE_CODE_FLT
      && (valtype->length () == 4 || valtype->length () == 8))
    {
      struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum);
      gdb_byte regval[8];

      /* FIXME: kettenis/2007-01-01: Add support for quadword
	 precision and complex.  */

      if (readbuf)
	{
	  regcache->cooked_read (tdep->ppc_fp0_regnum + 1, regval);
	  target_float_convert (regval, regtype, readbuf, valtype);
	}
      if (writebuf)
	{
	  target_float_convert (writebuf, valtype, regval, regtype);
	  regcache->cooked_write (tdep->ppc_fp0_regnum + 1, regval);
	}

      return RETURN_VALUE_REGISTER_CONVENTION;
  }

  /* Values of the types int, long, short, pointer, and char (length
     is less than or equal to four bytes), as well as bit values of
     lengths less than or equal to 32 bits, must be returned right
     justified in GPR3 with signed values sign extended and unsigned
     values zero extended, as necessary.  */
  if (valtype->length () <= tdep->wordsize)
    {
      if (readbuf)
	{
	  ULONGEST regval;

	  /* For reading we don't have to worry about sign extension.  */
	  regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					 &regval);
	  store_unsigned_integer (readbuf, valtype->length (), byte_order,
				  regval);
	}
      if (writebuf)
	{
	  /* For writing, use unpack_long since that should handle any
	     required sign extension.  */
	  regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					  unpack_long (valtype, writebuf));
	}

      return RETURN_VALUE_REGISTER_CONVENTION;
    }

  /* Eight-byte non-floating-point scalar values must be returned in
     GPR3:GPR4.  */

  if (valtype->length () == 8)
    {
      gdb_assert (valtype->code () != TYPE_CODE_FLT);
      gdb_assert (tdep->wordsize == 4);

      if (readbuf)
	{
	  gdb_byte regval[8];

	  regcache->cooked_read (tdep->ppc_gp0_regnum + 3, regval);
	  regcache->cooked_read (tdep->ppc_gp0_regnum + 4, regval + 4);
	  memcpy (readbuf, regval, 8);
	}
      if (writebuf)
	{
	  regcache->cooked_write (tdep->ppc_gp0_regnum + 3, writebuf);
	  regcache->cooked_write (tdep->ppc_gp0_regnum + 4, writebuf + 4);
	}

      return RETURN_VALUE_REGISTER_CONVENTION;
    }

  return RETURN_VALUE_STRUCT_CONVENTION;
}

/* Support for CONVERT_FROM_FUNC_PTR_ADDR (ARCH, ADDR, TARG).

   Usually a function pointer's representation is simply the address
   of the function.  On the RS/6000 however, a function pointer is
   represented by a pointer to an OPD entry.  This OPD entry contains
   three words, the first word is the address of the function, the
   second word is the TOC pointer (r2), and the third word is the
   static chain value.  Throughout GDB it is currently assumed that a
   function pointer contains the address of the function, which is not
   easy to fix.  In addition, the conversion of a function address to
   a function pointer would require allocation of an OPD entry in the
   inferior's memory space, with all its drawbacks.  To be able to
   call C++ virtual methods in the inferior (which are called via
   function pointers), find_function_addr uses this function to get the
   function address from a function pointer.  */

/* Return real function address if ADDR (a function pointer) is in the data
   space and is therefore a special function pointer.  */

static CORE_ADDR
rs6000_convert_from_func_ptr_addr (struct gdbarch *gdbarch,
				   CORE_ADDR addr,
				   struct target_ops *targ)
{
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  struct obj_section *s;

  s = find_pc_section (addr);

  /* Normally, functions live inside a section that is executable.
     So, if ADDR points to a non-executable section, then treat it
     as a function descriptor and return the target address iff
     the target address itself points to a section that is executable.  */
  if (s && (s->the_bfd_section->flags & SEC_CODE) == 0)
    {
      CORE_ADDR pc = 0;
      struct obj_section *pc_section;

      try
	{
	  pc = read_memory_unsigned_integer (addr, tdep->wordsize, byte_order);
	}
      catch (const gdb_exception_error &e)
	{
	  /* An error occurred during reading.  Probably a memory error
	     due to the section not being loaded yet.  This address
	     cannot be a function descriptor.  */
	  return addr;
	}

      pc_section = find_pc_section (pc);

      if (pc_section && (pc_section->the_bfd_section->flags & SEC_CODE))
	return pc;
    }

  return addr;
}


/* Calculate the destination of a branch/jump.  Return -1 if not a branch.  */

static CORE_ADDR
branch_dest (struct regcache *regcache, int opcode, int instr,
	     CORE_ADDR pc, CORE_ADDR safety)
{
  struct gdbarch *gdbarch = regcache->arch ();
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  CORE_ADDR dest;
  int immediate;
  int absolute;
  int ext_op;

  absolute = (int) ((instr >> 1) & 1);

  switch (opcode)
    {
    case 18:
      immediate = ((instr & ~3) << 6) >> 6;	/* br unconditional */
      if (absolute)
	dest = immediate;
      else
	dest = pc + immediate;
      break;

    case 16:
      immediate = ((instr & ~3) << 16) >> 16;	/* br conditional */
      if (absolute)
	dest = immediate;
      else
	dest = pc + immediate;
      break;

    case 19:
      ext_op = (instr >> 1) & 0x3ff;

      if (ext_op == 16)		/* br conditional register */
	{
	  dest = regcache_raw_get_unsigned (regcache, tdep->ppc_lr_regnum) & ~3;

	  /* If we are about to return from a signal handler, dest is
	     something like 0x3c90.  The current frame is a signal handler
	     caller frame, upon completion of the sigreturn system call
	     execution will return to the saved PC in the frame.  */
	  if (dest < AIX_TEXT_SEGMENT_BASE)
	    {
	      frame_info_ptr frame = get_current_frame ();

	      dest = read_memory_unsigned_integer
		(get_frame_base (frame) + SIG_FRAME_PC_OFFSET,
		 tdep->wordsize, byte_order);
	    }
	}

      else if (ext_op == 528)	/* br cond to count reg */
	{
	  dest = regcache_raw_get_unsigned (regcache,
					    tdep->ppc_ctr_regnum) & ~3;

	  /* If we are about to execute a system call, dest is something
	     like 0x22fc or 0x3b00.  Upon completion the system call
	     will return to the address in the link register.  */
	  if (dest < AIX_TEXT_SEGMENT_BASE)
	    dest = regcache_raw_get_unsigned (regcache,
					      tdep->ppc_lr_regnum) & ~3;
	}
      else
	return -1;
      break;

    default:
      return -1;
    }
  return (dest < AIX_TEXT_SEGMENT_BASE) ? safety : dest;
}

/* AIX does not support PT_STEP.  Simulate it.  */

static std::vector<CORE_ADDR>
rs6000_software_single_step (struct regcache *regcache)
{
  struct gdbarch *gdbarch = regcache->arch ();
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  int ii, insn;
  CORE_ADDR loc;
  CORE_ADDR breaks[2];
  int opcode;

  loc = regcache_read_pc (regcache);

  insn = read_memory_integer (loc, 4, byte_order);

  std::vector<CORE_ADDR> next_pcs = ppc_deal_with_atomic_sequence (regcache);
  if (!next_pcs.empty ())
    return next_pcs;
  
  /* Here 0xfc000000 is the opcode mask to detect a P10 prefix instruction.  */
  if ((insn & 0xfc000000) == 1 << 26)
    breaks[0] = loc + 2 * PPC_INSN_SIZE;
  else
    breaks[0] = loc + PPC_INSN_SIZE;
  opcode = insn >> 26;
  breaks[1] = branch_dest (regcache, opcode, insn, loc, breaks[0]);

  /* Don't put two breakpoints on the same address.  */
  if (breaks[1] == breaks[0])
    breaks[1] = -1;

  for (ii = 0; ii < 2; ++ii)
    {
      /* ignore invalid breakpoint.  */
      if (breaks[ii] == -1)
	continue;

      next_pcs.push_back (breaks[ii]);
    }

  errno = 0;			/* FIXME, don't ignore errors!  */
  /* What errors?  {read,write}_memory call error().  */
  return next_pcs;
}

/* Implement the "auto_wide_charset" gdbarch method for this platform.  */

static const char *
rs6000_aix_auto_wide_charset (void)
{
  return "UTF-16";
}

/* Implement an osabi sniffer for RS6000/AIX.

   This function assumes that ABFD's flavour is XCOFF.  In other words,
   it should be registered as a sniffer for bfd_target_xcoff_flavour
   objfiles only.  A failed assertion will be raised if this condition
   is not met.  */

static enum gdb_osabi
rs6000_aix_osabi_sniffer (bfd *abfd)
{
  gdb_assert (bfd_get_flavour (abfd) == bfd_target_xcoff_flavour);

  /* The only noticeable difference between Lynx178 XCOFF files and
     AIX XCOFF files comes from the fact that there are no shared
     libraries on Lynx178.  On AIX, we are betting that an executable
     linked with no shared library will never exist.  */
  if (xcoff_get_n_import_files (abfd) <= 0)
    return GDB_OSABI_UNKNOWN;

  return GDB_OSABI_AIX;
}

/* A structure encoding the offset and size of a field within
   a struct.  */

struct ldinfo_field
{
  int offset;
  int size;
};

/* A structure describing the layout of all the fields of interest
   in AIX's struct ld_info.  Each field in this struct corresponds
   to the field of the same name in struct ld_info.  */

struct ld_info_desc
{
  struct ldinfo_field ldinfo_next;
  struct ldinfo_field ldinfo_fd;
  struct ldinfo_field ldinfo_textorg;
  struct ldinfo_field ldinfo_textsize;
  struct ldinfo_field ldinfo_dataorg;
  struct ldinfo_field ldinfo_datasize;
  struct ldinfo_field ldinfo_filename;
};

/* The following data has been generated by compiling and running
   the following program on AIX 5.3.  */

#if 0
#include <stddef.h>
#include <stdio.h>
#define __LDINFO_PTRACE32__
#define __LDINFO_PTRACE64__
#include <sys/ldr.h>

#define pinfo(type,member)                  \
  {                                         \
    struct type ldi = {0};                  \
					    \
    printf ("  {%d, %d},\t/* %s */\n",      \
	    offsetof (struct type, member), \
	    sizeof (ldi.member),            \
	    #member);                       \
  }                                         \
  while (0)

int
main (void)
{
  printf ("static const struct ld_info_desc ld_info32_desc =\n{\n");
  pinfo (__ld_info32, ldinfo_next);
  pinfo (__ld_info32, ldinfo_fd);
  pinfo (__ld_info32, ldinfo_textorg);
  pinfo (__ld_info32, ldinfo_textsize);
  pinfo (__ld_info32, ldinfo_dataorg);
  pinfo (__ld_info32, ldinfo_datasize);
  pinfo (__ld_info32, ldinfo_filename);
  printf ("};\n");

  printf ("\n");

  printf ("static const struct ld_info_desc ld_info64_desc =\n{\n");
  pinfo (__ld_info64, ldinfo_next);
  pinfo (__ld_info64, ldinfo_fd);
  pinfo (__ld_info64, ldinfo_textorg);
  pinfo (__ld_info64, ldinfo_textsize);
  pinfo (__ld_info64, ldinfo_dataorg);
  pinfo (__ld_info64, ldinfo_datasize);
  pinfo (__ld_info64, ldinfo_filename);
  printf ("};\n");

  return 0;
}
#endif /* 0 */

/* Layout of the 32bit version of struct ld_info.  */

static const struct ld_info_desc ld_info32_desc =
{
  {0, 4},       /* ldinfo_next */
  {4, 4},       /* ldinfo_fd */
  {8, 4},       /* ldinfo_textorg */
  {12, 4},      /* ldinfo_textsize */
  {16, 4},      /* ldinfo_dataorg */
  {20, 4},      /* ldinfo_datasize */
  {24, 2},      /* ldinfo_filename */
};

/* Layout of the 64bit version of struct ld_info.  */

static const struct ld_info_desc ld_info64_desc =
{
  {0, 4},       /* ldinfo_next */
  {8, 4},       /* ldinfo_fd */
  {16, 8},      /* ldinfo_textorg */
  {24, 8},      /* ldinfo_textsize */
  {32, 8},      /* ldinfo_dataorg */
  {40, 8},      /* ldinfo_datasize */
  {48, 2},      /* ldinfo_filename */
};

/* A structured representation of one entry read from the ld_info
   binary data provided by the AIX loader.  */

struct ld_info
{
  ULONGEST next;
  int fd;
  CORE_ADDR textorg;
  ULONGEST textsize;
  CORE_ADDR dataorg;
  ULONGEST datasize;
  char *filename;
  char *member_name;
};

/* Return a struct ld_info object corresponding to the entry at
   LDI_BUF.

   Note that the filename and member_name strings still point
   to the data in LDI_BUF.  So LDI_BUF must not be deallocated
   while the struct ld_info object returned is in use.  */

static struct ld_info
rs6000_aix_extract_ld_info (struct gdbarch *gdbarch,
			    const gdb_byte *ldi_buf)
{
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
  const struct ld_info_desc desc
    = tdep->wordsize == 8 ? ld_info64_desc : ld_info32_desc;
  struct ld_info info;

  info.next = extract_unsigned_integer (ldi_buf + desc.ldinfo_next.offset,
					desc.ldinfo_next.size,
					byte_order);
  info.fd = extract_signed_integer (ldi_buf + desc.ldinfo_fd.offset,
				    desc.ldinfo_fd.size,
				    byte_order);
  info.textorg = extract_typed_address (ldi_buf + desc.ldinfo_textorg.offset,
					ptr_type);
  info.textsize
    = extract_unsigned_integer (ldi_buf + desc.ldinfo_textsize.offset,
				desc.ldinfo_textsize.size,
				byte_order);
  info.dataorg = extract_typed_address (ldi_buf + desc.ldinfo_dataorg.offset,
					ptr_type);
  info.datasize
    = extract_unsigned_integer (ldi_buf + desc.ldinfo_datasize.offset,
				desc.ldinfo_datasize.size,
				byte_order);
  info.filename = (char *) ldi_buf + desc.ldinfo_filename.offset;
  info.member_name = info.filename + strlen (info.filename) + 1;

  return info;
}

/* Append to XML an XML string description of the shared library
   corresponding to LDI, following the TARGET_OBJECT_LIBRARIES_AIX
   format.  */

static void
rs6000_aix_shared_library_to_xml (struct ld_info *ldi, std::string &xml)
{
  xml += "<library name=\"";
  xml_escape_text_append (xml, ldi->filename);
  xml += '"';

  if (ldi->member_name[0] != '\0')
    {
      xml += " member=\"";
      xml_escape_text_append (xml, ldi->member_name);
      xml += '"';
    }

  xml += " text_addr=\"";
  xml += core_addr_to_string (ldi->textorg);
  xml += '"';

  xml += " text_size=\"";
  xml += pulongest (ldi->textsize);
  xml += '"';

  xml += " data_addr=\"";
  xml += core_addr_to_string (ldi->dataorg);
  xml += '"';

  xml += " data_size=\"";
  xml += pulongest (ldi->datasize);
  xml += '"';

  xml += "></library>";
}

/* Convert the ld_info binary data provided by the AIX loader into
   an XML representation following the TARGET_OBJECT_LIBRARIES_AIX
   format.

   LDI_BUF is a buffer containing the ld_info data.
   READBUF, OFFSET and LEN follow the same semantics as target_ops'
   to_xfer_partial target_ops method.

   If CLOSE_LDINFO_FD is nonzero, then this routine also closes
   the ldinfo_fd file descriptor.  This is useful when the ldinfo
   data is obtained via ptrace, as ptrace opens a file descriptor
   for each and every entry; but we cannot use this descriptor
   as the consumer of the XML library list might live in a different
   process.  */

ULONGEST
rs6000_aix_ld_info_to_xml (struct gdbarch *gdbarch, const gdb_byte *ldi_buf,
			   gdb_byte *readbuf, ULONGEST offset, ULONGEST len,
			   int close_ldinfo_fd)
{
  std::string xml = "<library-list-aix version=\"1.0\">\n";

  while (1)
    {
      struct ld_info ldi = rs6000_aix_extract_ld_info (gdbarch, ldi_buf);

      rs6000_aix_shared_library_to_xml (&ldi, xml);
      if (close_ldinfo_fd)
	close (ldi.fd);

      if (!ldi.next)
	break;
      ldi_buf = ldi_buf + ldi.next;
    }

  xml += "</library-list-aix>\n";

  ULONGEST len_avail = xml.length ();
  if (offset >= len_avail)
    len= 0;
  else
    {
      if (len > len_avail - offset)
	len = len_avail - offset;
      memcpy (readbuf, xml.data () + offset, len);
    }

  return len;
}

/* Implement the core_xfer_shared_libraries_aix gdbarch method.  */

static ULONGEST
rs6000_aix_core_xfer_shared_libraries_aix (struct gdbarch *gdbarch,
					   gdb_byte *readbuf,
					   ULONGEST offset,
					   ULONGEST len)
{
  struct bfd_section *ldinfo_sec;
  int ldinfo_size;

  ldinfo_sec = bfd_get_section_by_name (core_bfd, ".ldinfo");
  if (ldinfo_sec == NULL)
    error (_("cannot find .ldinfo section from core file: %s"),
	   bfd_errmsg (bfd_get_error ()));
  ldinfo_size = bfd_section_size (ldinfo_sec);

  gdb::byte_vector ldinfo_buf (ldinfo_size);

  if (! bfd_get_section_contents (core_bfd, ldinfo_sec,
				  ldinfo_buf.data (), 0, ldinfo_size))
    error (_("unable to read .ldinfo section from core file: %s"),
	  bfd_errmsg (bfd_get_error ()));

  return rs6000_aix_ld_info_to_xml (gdbarch, ldinfo_buf.data (), readbuf,
				    offset, len, 0);
}

static void
rs6000_aix_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);

  /* RS6000/AIX does not support PT_STEP.  Has to be simulated.  */
  set_gdbarch_software_single_step (gdbarch, rs6000_software_single_step);

  /* Displaced stepping is currently not supported in combination with
     software single-stepping.  These override the values set by
     rs6000_gdbarch_init.  */
  set_gdbarch_displaced_step_copy_insn (gdbarch, NULL);
  set_gdbarch_displaced_step_fixup (gdbarch, NULL);
  set_gdbarch_displaced_step_prepare (gdbarch, NULL);
  set_gdbarch_displaced_step_finish (gdbarch, NULL);

  set_gdbarch_push_dummy_call (gdbarch, rs6000_push_dummy_call);
  set_gdbarch_return_value (gdbarch, rs6000_return_value);
  set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT);

  /* Handle RS/6000 function pointers (which are really function
     descriptors).  */
  set_gdbarch_convert_from_func_ptr_addr
    (gdbarch, rs6000_convert_from_func_ptr_addr);

  /* Core file support.  */
  set_gdbarch_iterate_over_regset_sections
    (gdbarch, rs6000_aix_iterate_over_regset_sections);
  set_gdbarch_core_xfer_shared_libraries_aix
    (gdbarch, rs6000_aix_core_xfer_shared_libraries_aix);
  set_gdbarch_core_read_description (gdbarch, ppc_aix_core_read_description);

  if (tdep->wordsize == 8)
    tdep->lr_frame_offset = 16;
  else
    tdep->lr_frame_offset = 8;

  if (tdep->wordsize == 4)
    /* PowerOpen / AIX 32 bit.  The saved area or red zone consists of
       19 4 byte GPRS + 18 8 byte FPRs giving a total of 220 bytes.
       Problem is, 220 isn't frame (16 byte) aligned.  Round it up to
       224.  */
    set_gdbarch_frame_red_zone_size (gdbarch, 224);
  else
    /* In 64 bit mode the red zone should have 18 8 byte GPRS + 18 8 byte
       FPRS making it 288 bytes.  This is 16 byte aligned as well.  */
    set_gdbarch_frame_red_zone_size (gdbarch, 288);

  if (tdep->wordsize == 8)
    set_gdbarch_wchar_bit (gdbarch, 32);
  else
    set_gdbarch_wchar_bit (gdbarch, 16);
  set_gdbarch_wchar_signed (gdbarch, 0);
  set_gdbarch_auto_wide_charset (gdbarch, rs6000_aix_auto_wide_charset);

  set_gdbarch_so_ops (gdbarch, &solib_aix_so_ops);
  frame_unwind_append_unwinder (gdbarch, &aix_sighandle_frame_unwind);
}

void _initialize_rs6000_aix_tdep ();
void
_initialize_rs6000_aix_tdep ()
{
  gdbarch_register_osabi_sniffer (bfd_arch_rs6000,
				  bfd_target_xcoff_flavour,
				  rs6000_aix_osabi_sniffer);
  gdbarch_register_osabi_sniffer (bfd_arch_powerpc,
				  bfd_target_xcoff_flavour,
				  rs6000_aix_osabi_sniffer);

  gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_AIX,
			  rs6000_aix_init_osabi);
  gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_AIX,
			  rs6000_aix_init_osabi);
}