summaryrefslogtreecommitdiff
path: root/gdb/blockframe.c
blob: 6ce753ef02e4194badeb1e78b77ef22f72c8fc01 (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
/* Get info from stack frames;
   convert between frames, blocks, functions and pc values.
   Copyright 1986, 87, 88, 89, 91, 94, 95, 96, 97, 1998
   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 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "symtab.h"
#include "bfd.h"
#include "symfile.h"
#include "objfiles.h"
#include "frame.h"
#include "gdbcore.h"
#include "value.h"		/* for read_register */
#include "target.h"		/* for target_has_stack */
#include "inferior.h"		/* for read_pc */
#include "annotate.h"

/* Prototypes for exported functions. */

void _initialize_blockframe (void);

/* A default FRAME_CHAIN_VALID, in the form that is suitable for most
   targets.  If FRAME_CHAIN_VALID returns zero it means that the given
   frame is the outermost one and has no caller. */

int
file_frame_chain_valid (chain, thisframe)
     CORE_ADDR chain;
     struct frame_info *thisframe;
{
  return ((chain) != 0
	  && !inside_entry_file (FRAME_SAVED_PC (thisframe)));
}

/* Use the alternate method of avoiding running up off the end of the
   frame chain or following frames back into the startup code.  See
   the comments in objfiles.h. */

int
func_frame_chain_valid (chain, thisframe)
     CORE_ADDR chain;
     struct frame_info *thisframe;
{
  return ((chain) != 0
	  && !inside_main_func ((thisframe)->pc)
	  && !inside_entry_func ((thisframe)->pc));
}

/* A very simple method of determining a valid frame */

int
nonnull_frame_chain_valid (chain, thisframe)
     CORE_ADDR chain;
     struct frame_info *thisframe;
{
  return ((chain) != 0);
}

/* Is ADDR inside the startup file?  Note that if your machine
   has a way to detect the bottom of the stack, there is no need
   to call this function from FRAME_CHAIN_VALID; the reason for
   doing so is that some machines have no way of detecting bottom
   of stack. 

   A PC of zero is always considered to be the bottom of the stack. */

int
inside_entry_file (addr)
     CORE_ADDR addr;
{
  if (addr == 0)
    return 1;
  if (symfile_objfile == 0)
    return 0;
  if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
    {
      /* Do not stop backtracing if the pc is in the call dummy
         at the entry point.  */
      /* FIXME: Won't always work with zeros for the last two arguments */
      if (PC_IN_CALL_DUMMY (addr, 0, 0))
	return 0;
    }
  return (addr >= symfile_objfile->ei.entry_file_lowpc &&
	  addr < symfile_objfile->ei.entry_file_highpc);
}

/* Test a specified PC value to see if it is in the range of addresses
   that correspond to the main() function.  See comments above for why
   we might want to do this.

   Typically called from FRAME_CHAIN_VALID.

   A PC of zero is always considered to be the bottom of the stack. */

int
inside_main_func (pc)
     CORE_ADDR pc;
{
  if (pc == 0)
    return 1;
  if (symfile_objfile == 0)
    return 0;

  /* If the addr range is not set up at symbol reading time, set it up now.
     This is for FRAME_CHAIN_VALID_ALTERNATE. I do this for coff, because
     it is unable to set it up and symbol reading time. */

  if (symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC &&
      symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
    {
      struct symbol *mainsym;

      mainsym = lookup_symbol ("main", NULL, VAR_NAMESPACE, NULL, NULL);
      if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
	{
	  symfile_objfile->ei.main_func_lowpc =
	    BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
	  symfile_objfile->ei.main_func_highpc =
	    BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
	}
    }
  return (symfile_objfile->ei.main_func_lowpc <= pc &&
	  symfile_objfile->ei.main_func_highpc > pc);
}

/* Test a specified PC value to see if it is in the range of addresses
   that correspond to the process entry point function.  See comments
   in objfiles.h for why we might want to do this.

   Typically called from FRAME_CHAIN_VALID.

   A PC of zero is always considered to be the bottom of the stack. */

int
inside_entry_func (pc)
     CORE_ADDR pc;
{
  if (pc == 0)
    return 1;
  if (symfile_objfile == 0)
    return 0;
  if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
    {
      /* Do not stop backtracing if the pc is in the call dummy
         at the entry point.  */
      /* FIXME: Won't always work with zeros for the last two arguments */
      if (PC_IN_CALL_DUMMY (pc, 0, 0))
	return 0;
    }
  return (symfile_objfile->ei.entry_func_lowpc <= pc &&
	  symfile_objfile->ei.entry_func_highpc > pc);
}

/* Info about the innermost stack frame (contents of FP register) */

static struct frame_info *current_frame;

/* Cache for frame addresses already read by gdb.  Valid only while
   inferior is stopped.  Control variables for the frame cache should
   be local to this module.  */

static struct obstack frame_cache_obstack;

void *
frame_obstack_alloc (size)
     unsigned long size;
{
  return obstack_alloc (&frame_cache_obstack, size);
}

void
frame_saved_regs_zalloc (fi)
     struct frame_info *fi;
{
  fi->saved_regs = (CORE_ADDR *)
    frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
  memset (fi->saved_regs, 0, SIZEOF_FRAME_SAVED_REGS);
}


/* Return the innermost (currently executing) stack frame.  */

struct frame_info *
get_current_frame ()
{
  if (current_frame == NULL)
    {
      if (target_has_stack)
	current_frame = create_new_frame (read_fp (), read_pc ());
      else
	error ("No stack.");
    }
  return current_frame;
}

void
set_current_frame (frame)
     struct frame_info *frame;
{
  current_frame = frame;
}

/* Create an arbitrary (i.e. address specified by user) or innermost frame.
   Always returns a non-NULL value.  */

struct frame_info *
create_new_frame (addr, pc)
     CORE_ADDR addr;
     CORE_ADDR pc;
{
  struct frame_info *fi;
  char *name;

  fi = (struct frame_info *)
    obstack_alloc (&frame_cache_obstack,
		   sizeof (struct frame_info));

  /* Arbitrary frame */
  fi->saved_regs = NULL;
  fi->next = NULL;
  fi->prev = NULL;
  fi->frame = addr;
  fi->pc = pc;
  find_pc_partial_function (pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL);
  fi->signal_handler_caller = IN_SIGTRAMP (fi->pc, name);

#ifdef INIT_EXTRA_FRAME_INFO
  INIT_EXTRA_FRAME_INFO (0, fi);
#endif

  return fi;
}

/* Return the frame that FRAME calls (NULL if FRAME is the innermost
   frame).  */

struct frame_info *
get_next_frame (frame)
     struct frame_info *frame;
{
  return frame->next;
}

/* Flush the entire frame cache.  */

void
flush_cached_frames ()
{
  /* Since we can't really be sure what the first object allocated was */
  obstack_free (&frame_cache_obstack, 0);
  obstack_init (&frame_cache_obstack);

  current_frame = NULL;		/* Invalidate cache */
  select_frame (NULL, -1);
  annotate_frames_invalid ();
}

/* Flush the frame cache, and start a new one if necessary.  */

void
reinit_frame_cache ()
{
  flush_cached_frames ();

  /* FIXME: The inferior_pid test is wrong if there is a corefile.  */
  if (inferior_pid != 0)
    {
      select_frame (get_current_frame (), 0);
    }
}

/* Return nonzero if the function for this frame lacks a prologue.  Many
   machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
   function.  */

int
frameless_look_for_prologue (frame)
     struct frame_info *frame;
{
  CORE_ADDR func_start, after_prologue;

  func_start = get_pc_function_start (frame->pc);
  if (func_start)
    {
      func_start += FUNCTION_START_OFFSET;
      after_prologue = func_start;
#ifdef SKIP_PROLOGUE_FRAMELESS_P
      /* This is faster, since only care whether there *is* a
         prologue, not how long it is.  */
      after_prologue = SKIP_PROLOGUE_FRAMELESS_P (after_prologue);
#else
      after_prologue = SKIP_PROLOGUE (after_prologue);
#endif
      return after_prologue == func_start;
    }
  else if (frame->pc == 0)
    /* A frame with a zero PC is usually created by dereferencing a
       NULL function pointer, normally causing an immediate core dump
       of the inferior. Mark function as frameless, as the inferior
       has no chance of setting up a stack frame.  */
    return 1;
  else
    /* If we can't find the start of the function, we don't really
       know whether the function is frameless, but we should be able
       to get a reasonable (i.e. best we can do under the
       circumstances) backtrace by saying that it isn't.  */
    return 0;
}

/* Default a few macros that people seldom redefine.  */

#if !defined (INIT_FRAME_PC)
#define INIT_FRAME_PC(fromleaf, prev) \
  prev->pc = (fromleaf ? SAVED_PC_AFTER_CALL (prev->next) : \
	      prev->next ? FRAME_SAVED_PC (prev->next) : read_pc ());
#endif

#ifndef FRAME_CHAIN_COMBINE
#define	FRAME_CHAIN_COMBINE(chain, thisframe) (chain)
#endif

/* Return a structure containing various interesting information
   about the frame that called NEXT_FRAME.  Returns NULL
   if there is no such frame.  */

struct frame_info *
get_prev_frame (next_frame)
     struct frame_info *next_frame;
{
  CORE_ADDR address = 0;
  struct frame_info *prev;
  int fromleaf = 0;
  char *name;

  /* If the requested entry is in the cache, return it.
     Otherwise, figure out what the address should be for the entry
     we're about to add to the cache. */

  if (!next_frame)
    {
#if 0
      /* This screws value_of_variable, which just wants a nice clean
         NULL return from block_innermost_frame if there are no frames.
         I don't think I've ever seen this message happen otherwise.
         And returning NULL here is a perfectly legitimate thing to do.  */
      if (!current_frame)
	{
	  error ("You haven't set up a process's stack to examine.");
	}
#endif

      return current_frame;
    }

  /* If we have the prev one, return it */
  if (next_frame->prev)
    return next_frame->prev;

  /* On some machines it is possible to call a function without
     setting up a stack frame for it.  On these machines, we
     define this macro to take two args; a frameinfo pointer
     identifying a frame and a variable to set or clear if it is
     or isn't leafless.  */

  /* Still don't want to worry about this except on the innermost
     frame.  This macro will set FROMLEAF if NEXT_FRAME is a
     frameless function invocation.  */
  if (!(next_frame->next))
    {
      fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame);
      if (fromleaf)
	address = FRAME_FP (next_frame);
    }

  if (!fromleaf)
    {
      /* Two macros defined in tm.h specify the machine-dependent
         actions to be performed here.
         First, get the frame's chain-pointer.
         If that is zero, the frame is the outermost frame or a leaf
         called by the outermost frame.  This means that if start
         calls main without a frame, we'll return 0 (which is fine
         anyway).

         Nope; there's a problem.  This also returns when the current
         routine is a leaf of main.  This is unacceptable.  We move
         this to after the ffi test; I'd rather have backtraces from
         start go curfluy than have an abort called from main not show
         main.  */
      address = FRAME_CHAIN (next_frame);
      if (!FRAME_CHAIN_VALID (address, next_frame))
	return 0;
      address = FRAME_CHAIN_COMBINE (address, next_frame);
    }
  if (address == 0)
    return 0;

  prev = (struct frame_info *)
    obstack_alloc (&frame_cache_obstack,
		   sizeof (struct frame_info));

  prev->saved_regs = NULL;
  if (next_frame)
    next_frame->prev = prev;
  prev->next = next_frame;
  prev->prev = (struct frame_info *) 0;
  prev->frame = address;
  prev->signal_handler_caller = 0;

/* This change should not be needed, FIXME!  We should
   determine whether any targets *need* INIT_FRAME_PC to happen
   after INIT_EXTRA_FRAME_INFO and come up with a simple way to
   express what goes on here.

   INIT_EXTRA_FRAME_INFO is called from two places: create_new_frame
   (where the PC is already set up) and here (where it isn't).
   INIT_FRAME_PC is only called from here, always after
   INIT_EXTRA_FRAME_INFO.

   The catch is the MIPS, where INIT_EXTRA_FRAME_INFO requires the PC
   value (which hasn't been set yet).  Some other machines appear to
   require INIT_EXTRA_FRAME_INFO before they can do INIT_FRAME_PC.  Phoo.

   We shouldn't need INIT_FRAME_PC_FIRST to add more complication to
   an already overcomplicated part of GDB.   gnu@cygnus.com, 15Sep92.

   Assuming that some machines need INIT_FRAME_PC after
   INIT_EXTRA_FRAME_INFO, one possible scheme:

   SETUP_INNERMOST_FRAME()
   Default version is just create_new_frame (read_fp ()),
   read_pc ()).  Machines with extra frame info would do that (or the
   local equivalent) and then set the extra fields.
   SETUP_ARBITRARY_FRAME(argc, argv)
   Only change here is that create_new_frame would no longer init extra
   frame info; SETUP_ARBITRARY_FRAME would have to do that.
   INIT_PREV_FRAME(fromleaf, prev)
   Replace INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC.  This should
   also return a flag saying whether to keep the new frame, or
   whether to discard it, because on some machines (e.g.  mips) it
   is really awkward to have FRAME_CHAIN_VALID called *before*
   INIT_EXTRA_FRAME_INFO (there is no good way to get information
   deduced in FRAME_CHAIN_VALID into the extra fields of the new frame).
   std_frame_pc(fromleaf, prev)
   This is the default setting for INIT_PREV_FRAME.  It just does what
   the default INIT_FRAME_PC does.  Some machines will call it from
   INIT_PREV_FRAME (either at the beginning, the end, or in the middle).
   Some machines won't use it.
   kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94.  */

#ifdef INIT_FRAME_PC_FIRST
  INIT_FRAME_PC_FIRST (fromleaf, prev);
#endif

#ifdef INIT_EXTRA_FRAME_INFO
  INIT_EXTRA_FRAME_INFO (fromleaf, prev);
#endif

  /* This entry is in the frame queue now, which is good since
     FRAME_SAVED_PC may use that queue to figure out its value
     (see tm-sparc.h).  We want the pc saved in the inferior frame. */
  INIT_FRAME_PC (fromleaf, prev);

  /* If ->frame and ->pc are unchanged, we are in the process of getting
     ourselves into an infinite backtrace.  Some architectures check this
     in FRAME_CHAIN or thereabouts, but it seems like there is no reason
     this can't be an architecture-independent check.  */
  if (next_frame != NULL)
    {
      if (prev->frame == next_frame->frame
	  && prev->pc == next_frame->pc)
	{
	  next_frame->prev = NULL;
	  obstack_free (&frame_cache_obstack, prev);
	  return NULL;
	}
    }

  find_pc_partial_function (prev->pc, &name,
			    (CORE_ADDR *) NULL, (CORE_ADDR *) NULL);
  if (IN_SIGTRAMP (prev->pc, name))
    prev->signal_handler_caller = 1;

  return prev;
}

CORE_ADDR
get_frame_pc (frame)
     struct frame_info *frame;
{
  return frame->pc;
}


#ifdef FRAME_FIND_SAVED_REGS
/* XXX - deprecated.  This is a compatibility function for targets
   that do not yet implement FRAME_INIT_SAVED_REGS.  */
/* Find the addresses in which registers are saved in FRAME.  */

void
get_frame_saved_regs (frame, saved_regs_addr)
     struct frame_info *frame;
     struct frame_saved_regs *saved_regs_addr;
{
  if (frame->saved_regs == NULL)
    {
      frame->saved_regs = (CORE_ADDR *)
	frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
    }
  if (saved_regs_addr == NULL)
    {
      struct frame_saved_regs saved_regs;
      FRAME_FIND_SAVED_REGS (frame, saved_regs);
      memcpy (frame->saved_regs, &saved_regs, SIZEOF_FRAME_SAVED_REGS);
    }
  else
    {
      FRAME_FIND_SAVED_REGS (frame, *saved_regs_addr);
      memcpy (frame->saved_regs, saved_regs_addr, SIZEOF_FRAME_SAVED_REGS);
    }
}
#endif

/* Return the innermost lexical block in execution
   in a specified stack frame.  The frame address is assumed valid.  */

struct block *
get_frame_block (frame)
     struct frame_info *frame;
{
  CORE_ADDR pc;

  pc = frame->pc;
  if (frame->next != 0 && frame->next->signal_handler_caller == 0)
    /* We are not in the innermost frame and we were not interrupted
       by a signal.  We need to subtract one to get the correct block,
       in case the call instruction was the last instruction of the block.
       If there are any machines on which the saved pc does not point to
       after the call insn, we probably want to make frame->pc point after
       the call insn anyway.  */
    --pc;
  return block_for_pc (pc);
}

struct block *
get_current_block ()
{
  return block_for_pc (read_pc ());
}

CORE_ADDR
get_pc_function_start (pc)
     CORE_ADDR pc;
{
  register struct block *bl;
  register struct symbol *symbol;
  register struct minimal_symbol *msymbol;
  CORE_ADDR fstart;

  if ((bl = block_for_pc (pc)) != NULL &&
      (symbol = block_function (bl)) != NULL)
    {
      bl = SYMBOL_BLOCK_VALUE (symbol);
      fstart = BLOCK_START (bl);
    }
  else if ((msymbol = lookup_minimal_symbol_by_pc (pc)) != NULL)
    {
      fstart = SYMBOL_VALUE_ADDRESS (msymbol);
    }
  else
    {
      fstart = 0;
    }
  return (fstart);
}

/* Return the symbol for the function executing in frame FRAME.  */

struct symbol *
get_frame_function (frame)
     struct frame_info *frame;
{
  register struct block *bl = get_frame_block (frame);
  if (bl == 0)
    return 0;
  return block_function (bl);
}


/* Return the blockvector immediately containing the innermost lexical block
   containing the specified pc value and section, or 0 if there is none.
   PINDEX is a pointer to the index value of the block.  If PINDEX
   is NULL, we don't pass this information back to the caller.  */

struct blockvector *
blockvector_for_pc_sect (pc, section, pindex, symtab)
     register CORE_ADDR pc;
     struct sec *section;
     int *pindex;
     struct symtab *symtab;

{
  register struct block *b;
  register int bot, top, half;
  struct blockvector *bl;

  if (symtab == 0)		/* if no symtab specified by caller */
    {
      /* First search all symtabs for one whose file contains our pc */
      if ((symtab = find_pc_sect_symtab (pc, section)) == 0)
	return 0;
    }

  bl = BLOCKVECTOR (symtab);
  b = BLOCKVECTOR_BLOCK (bl, 0);

  /* Then search that symtab for the smallest block that wins.  */
  /* Use binary search to find the last block that starts before PC.  */

  bot = 0;
  top = BLOCKVECTOR_NBLOCKS (bl);

  while (top - bot > 1)
    {
      half = (top - bot + 1) >> 1;
      b = BLOCKVECTOR_BLOCK (bl, bot + half);
      if (BLOCK_START (b) <= pc)
	bot += half;
      else
	top = bot + half;
    }

  /* Now search backward for a block that ends after PC.  */

  while (bot >= 0)
    {
      b = BLOCKVECTOR_BLOCK (bl, bot);
      if (BLOCK_END (b) > pc)
	{
	  if (pindex)
	    *pindex = bot;
	  return bl;
	}
      bot--;
    }
  return 0;
}

/* Return the blockvector immediately containing the innermost lexical block
   containing the specified pc value, or 0 if there is none.
   Backward compatibility, no section.  */

struct blockvector *
blockvector_for_pc (pc, pindex)
     register CORE_ADDR pc;
     int *pindex;
{
  return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),
				  pindex, NULL);
}

/* Return the innermost lexical block containing the specified pc value
   in the specified section, or 0 if there is none.  */

struct block *
block_for_pc_sect (pc, section)
     register CORE_ADDR pc;
     struct sec *section;
{
  register struct blockvector *bl;
  int index;

  bl = blockvector_for_pc_sect (pc, section, &index, NULL);
  if (bl)
    return BLOCKVECTOR_BLOCK (bl, index);
  return 0;
}

/* Return the innermost lexical block containing the specified pc value,
   or 0 if there is none.  Backward compatibility, no section.  */

struct block *
block_for_pc (pc)
     register CORE_ADDR pc;
{
  return block_for_pc_sect (pc, find_pc_mapped_section (pc));
}

/* Return the function containing pc value PC in section SECTION.
   Returns 0 if function is not known.  */

struct symbol *
find_pc_sect_function (pc, section)
     CORE_ADDR pc;
     struct sec *section;
{
  register struct block *b = block_for_pc_sect (pc, section);
  if (b == 0)
    return 0;
  return block_function (b);
}

/* Return the function containing pc value PC.
   Returns 0 if function is not known.  Backward compatibility, no section */

struct symbol *
find_pc_function (pc)
     CORE_ADDR pc;
{
  return find_pc_sect_function (pc, find_pc_mapped_section (pc));
}

/* These variables are used to cache the most recent result
 * of find_pc_partial_function. */

static CORE_ADDR cache_pc_function_low = 0;
static CORE_ADDR cache_pc_function_high = 0;
static char *cache_pc_function_name = 0;
static struct sec *cache_pc_function_section = NULL;

/* Clear cache, e.g. when symbol table is discarded. */

void
clear_pc_function_cache ()
{
  cache_pc_function_low = 0;
  cache_pc_function_high = 0;
  cache_pc_function_name = (char *) 0;
  cache_pc_function_section = NULL;
}

/* Finds the "function" (text symbol) that is smaller than PC but
   greatest of all of the potential text symbols in SECTION.  Sets
   *NAME and/or *ADDRESS conditionally if that pointer is non-null.
   If ENDADDR is non-null, then set *ENDADDR to be the end of the
   function (exclusive), but passing ENDADDR as non-null means that
   the function might cause symbols to be read.  This function either
   succeeds or fails (not halfway succeeds).  If it succeeds, it sets
   *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
   If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
   returns 0.  */

int
find_pc_sect_partial_function (pc, section, name, address, endaddr)
     CORE_ADDR pc;
     asection *section;
     char **name;
     CORE_ADDR *address;
     CORE_ADDR *endaddr;
{
  struct partial_symtab *pst;
  struct symbol *f;
  struct minimal_symbol *msymbol;
  struct partial_symbol *psb;
  struct obj_section *osect;
  int i;
  CORE_ADDR mapped_pc;

  mapped_pc = overlay_mapped_address (pc, section);

  if (mapped_pc >= cache_pc_function_low &&
      mapped_pc < cache_pc_function_high &&
      section == cache_pc_function_section)
    goto return_cached_value;

  /* If sigtramp is in the u area, it counts as a function (especially
     important for step_1).  */
#if defined SIGTRAMP_START
  if (IN_SIGTRAMP (mapped_pc, (char *) NULL))
    {
      cache_pc_function_low = SIGTRAMP_START (mapped_pc);
      cache_pc_function_high = SIGTRAMP_END (mapped_pc);
      cache_pc_function_name = "<sigtramp>";
      cache_pc_function_section = section;
      goto return_cached_value;
    }
#endif

  msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
  pst = find_pc_sect_psymtab (mapped_pc, section);
  if (pst)
    {
      /* Need to read the symbols to get a good value for the end address.  */
      if (endaddr != NULL && !pst->readin)
	{
	  /* Need to get the terminal in case symbol-reading produces
	     output.  */
	  target_terminal_ours_for_output ();
	  PSYMTAB_TO_SYMTAB (pst);
	}

      if (pst->readin)
	{
	  /* Checking whether the msymbol has a larger value is for the
	     "pathological" case mentioned in print_frame_info.  */
	  f = find_pc_sect_function (mapped_pc, section);
	  if (f != NULL
	      && (msymbol == NULL
		  || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
		      >= SYMBOL_VALUE_ADDRESS (msymbol))))
	    {
	      cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
	      cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
	      cache_pc_function_name = SYMBOL_NAME (f);
	      cache_pc_function_section = section;
	      goto return_cached_value;
	    }
	}
      else
	{
	  /* Now that static symbols go in the minimal symbol table, perhaps
	     we could just ignore the partial symbols.  But at least for now
	     we use the partial or minimal symbol, whichever is larger.  */
	  psb = find_pc_sect_psymbol (pst, mapped_pc, section);

	  if (psb
	      && (msymbol == NULL ||
		  (SYMBOL_VALUE_ADDRESS (psb)
		   >= SYMBOL_VALUE_ADDRESS (msymbol))))
	    {
	      /* This case isn't being cached currently. */
	      if (address)
		*address = SYMBOL_VALUE_ADDRESS (psb);
	      if (name)
		*name = SYMBOL_NAME (psb);
	      /* endaddr non-NULL can't happen here.  */
	      return 1;
	    }
	}
    }

  /* Not in the normal symbol tables, see if the pc is in a known section.
     If it's not, then give up.  This ensures that anything beyond the end
     of the text seg doesn't appear to be part of the last function in the
     text segment.  */

  osect = find_pc_sect_section (mapped_pc, section);

  if (!osect)
    msymbol = NULL;

  /* Must be in the minimal symbol table.  */
  if (msymbol == NULL)
    {
      /* No available symbol.  */
      if (name != NULL)
	*name = 0;
      if (address != NULL)
	*address = 0;
      if (endaddr != NULL)
	*endaddr = 0;
      return 0;
    }

  cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
  cache_pc_function_name = SYMBOL_NAME (msymbol);
  cache_pc_function_section = section;

  /* Use the lesser of the next minimal symbol in the same section, or
     the end of the section, as the end of the function.  */

  /* Step over other symbols at this same address, and symbols in
     other sections, to find the next symbol in this section with
     a different address.  */

  for (i = 1; SYMBOL_NAME (msymbol + i) != NULL; i++)
    {
      if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
	&& SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
	break;
    }

  if (SYMBOL_NAME (msymbol + i) != NULL
      && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
    cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
  else
    /* We got the start address from the last msymbol in the objfile.
       So the end address is the end of the section.  */
    cache_pc_function_high = osect->endaddr;

return_cached_value:

  if (address)
    {
      if (pc_in_unmapped_range (pc, section))
	*address = overlay_unmapped_address (cache_pc_function_low, section);
      else
	*address = cache_pc_function_low;
    }

  if (name)
    *name = cache_pc_function_name;

  if (endaddr)
    {
      if (pc_in_unmapped_range (pc, section))
	{
	  /* Because the high address is actually beyond the end of
	     the function (and therefore possibly beyond the end of
	     the overlay), we must actually convert (high - 1)
	     and then add one to that. */

	  *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
						   section);
	}
      else
	*endaddr = cache_pc_function_high;
    }

  return 1;
}

/* Backward compatibility, no section argument */

int
find_pc_partial_function (pc, name, address, endaddr)
     CORE_ADDR pc;
     char **name;
     CORE_ADDR *address;
     CORE_ADDR *endaddr;
{
  asection *section;

  section = find_pc_overlay (pc);
  return find_pc_sect_partial_function (pc, section, name, address, endaddr);
}

/* Return the innermost stack frame executing inside of BLOCK,
   or NULL if there is no such frame.  If BLOCK is NULL, just return NULL.  */

struct frame_info *
block_innermost_frame (block)
     struct block *block;
{
  struct frame_info *frame;
  register CORE_ADDR start;
  register CORE_ADDR end;

  if (block == NULL)
    return NULL;

  start = BLOCK_START (block);
  end = BLOCK_END (block);

  frame = NULL;
  while (1)
    {
      frame = get_prev_frame (frame);
      if (frame == NULL)
	return NULL;
      if (frame->pc >= start && frame->pc < end)
	return frame;
    }
}

/* Return the full FRAME which corresponds to the given CORE_ADDR
   or NULL if no FRAME on the chain corresponds to CORE_ADDR.  */

struct frame_info *
find_frame_addr_in_frame_chain (frame_addr)
     CORE_ADDR frame_addr;
{
  struct frame_info *frame = NULL;

  if (frame_addr == (CORE_ADDR) 0)
    return NULL;

  while (1)
    {
      frame = get_prev_frame (frame);
      if (frame == NULL)
	return NULL;
      if (FRAME_FP (frame) == frame_addr)
	return frame;
    }
}

#ifdef SIGCONTEXT_PC_OFFSET
/* Get saved user PC for sigtramp from sigcontext for BSD style sigtramp.  */

CORE_ADDR
sigtramp_saved_pc (frame)
     struct frame_info *frame;
{
  CORE_ADDR sigcontext_addr;
  char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
  int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT;
  int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT;

  /* Get sigcontext address, it is the third parameter on the stack.  */
  if (frame->next)
    sigcontext_addr = read_memory_integer (FRAME_ARGS_ADDRESS (frame->next)
					   + FRAME_ARGS_SKIP
					   + sigcontext_offs,
					   ptrbytes);
  else
    sigcontext_addr = read_memory_integer (read_register (SP_REGNUM)
					   + sigcontext_offs,
					   ptrbytes);

  /* Don't cause a memory_error when accessing sigcontext in case the stack
     layout has changed or the stack is corrupt.  */
  target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes);
  return extract_unsigned_integer (buf, ptrbytes);
}
#endif /* SIGCONTEXT_PC_OFFSET */


/* Are we in a call dummy?  The code below which allows DECR_PC_AFTER_BREAK
   below is for infrun.c, which may give the macro a pc without that
   subtracted out.  */

extern CORE_ADDR text_end;

int
pc_in_call_dummy_before_text_end (pc, sp, frame_address)
     CORE_ADDR pc;
     CORE_ADDR sp;
     CORE_ADDR frame_address;
{
  return ((pc) >= text_end - CALL_DUMMY_LENGTH
	  && (pc) <= text_end + DECR_PC_AFTER_BREAK);
}

int
pc_in_call_dummy_after_text_end (pc, sp, frame_address)
     CORE_ADDR pc;
     CORE_ADDR sp;
     CORE_ADDR frame_address;
{
  return ((pc) >= text_end
	  && (pc) <= text_end + CALL_DUMMY_LENGTH + DECR_PC_AFTER_BREAK);
}

/* Is the PC in a call dummy?  SP and FRAME_ADDRESS are the bottom and
   top of the stack frame which we are checking, where "bottom" and
   "top" refer to some section of memory which contains the code for
   the call dummy.  Calls to this macro assume that the contents of
   SP_REGNUM and FP_REGNUM (or the saved values thereof), respectively,
   are the things to pass.

   This won't work on the 29k, where SP_REGNUM and FP_REGNUM don't
   have that meaning, but the 29k doesn't use ON_STACK.  This could be
   fixed by generalizing this scheme, perhaps by passing in a frame
   and adding a few fields, at least on machines which need them for
   PC_IN_CALL_DUMMY.

   Something simpler, like checking for the stack segment, doesn't work,
   since various programs (threads implementations, gcc nested function
   stubs, etc) may either allocate stack frames in another segment, or
   allocate other kinds of code on the stack.  */

int
pc_in_call_dummy_on_stack (pc, sp, frame_address)
     CORE_ADDR pc;
     CORE_ADDR sp;
     CORE_ADDR frame_address;
{
  return (INNER_THAN ((sp), (pc))
	  && (frame_address != 0)
	  && INNER_THAN ((pc), (frame_address)));
}

int
pc_in_call_dummy_at_entry_point (pc, sp, frame_address)
     CORE_ADDR pc;
     CORE_ADDR sp;
     CORE_ADDR frame_address;
{
  return ((pc) >= CALL_DUMMY_ADDRESS ()
	  && (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK));
}


/*
 * GENERIC DUMMY FRAMES
 * 
 * The following code serves to maintain the dummy stack frames for
 * inferior function calls (ie. when gdb calls into the inferior via
 * call_function_by_hand).  This code saves the machine state before 
 * the call in host memory, so we must maintain an independant stack 
 * and keep it consistant etc.  I am attempting to make this code 
 * generic enough to be used by many targets.
 *
 * The cheapest and most generic way to do CALL_DUMMY on a new target
 * is probably to define CALL_DUMMY to be empty, CALL_DUMMY_LENGTH to
 * zero, and CALL_DUMMY_LOCATION to AT_ENTRY.  Then you must remember
 * to define PUSH_RETURN_ADDRESS, because no call instruction will be
 * being executed by the target.  Also FRAME_CHAIN_VALID as
 * generic_{file,func}_frame_chain_valid and FIX_CALL_DUMMY as
 * generic_fix_call_dummy.  */

/* Dummy frame.  This saves the processor state just prior to setting
   up the inferior function call.  Older targets save the registers
   target stack (but that really slows down function calls).  */

struct dummy_frame
{
  struct dummy_frame *next;

  CORE_ADDR pc;
  CORE_ADDR fp;
  CORE_ADDR sp;
  CORE_ADDR top;
  char *registers;
};

static struct dummy_frame *dummy_frame_stack = NULL;

/* Function: find_dummy_frame(pc, fp, sp)
   Search the stack of dummy frames for one matching the given PC, FP and SP.
   This is the work-horse for pc_in_call_dummy and read_register_dummy     */

char *
generic_find_dummy_frame (pc, fp)
     CORE_ADDR pc;
     CORE_ADDR fp;
{
  struct dummy_frame *dummyframe;

  if (pc != entry_point_address ())
    return 0;

  for (dummyframe = dummy_frame_stack; dummyframe != NULL;
       dummyframe = dummyframe->next)
    if (fp == dummyframe->fp
	|| fp == dummyframe->sp
	|| fp == dummyframe->top)
      /* The frame in question lies between the saved fp and sp, inclusive */
      return dummyframe->registers;

  return 0;
}

/* Function: pc_in_call_dummy (pc, fp)
   Return true if this is a dummy frame created by gdb for an inferior call */

int
generic_pc_in_call_dummy (pc, sp, fp)
     CORE_ADDR pc;
     CORE_ADDR sp;
     CORE_ADDR fp;
{
  /* if find_dummy_frame succeeds, then PC is in a call dummy */
  /* Note: SP and not FP is passed on. */
  return (generic_find_dummy_frame (pc, sp) != 0);
}

/* Function: read_register_dummy 
   Find a saved register from before GDB calls a function in the inferior */

CORE_ADDR
generic_read_register_dummy (pc, fp, regno)
     CORE_ADDR pc;
     CORE_ADDR fp;
     int regno;
{
  char *dummy_regs = generic_find_dummy_frame (pc, fp);

  if (dummy_regs)
    return extract_address (&dummy_regs[REGISTER_BYTE (regno)],
			    REGISTER_RAW_SIZE (regno));
  else
    return 0;
}

/* Save all the registers on the dummy frame stack.  Most ports save the
   registers on the target stack.  This results in lots of unnecessary memory
   references, which are slow when debugging via a serial line.  Instead, we
   save all the registers internally, and never write them to the stack.  The
   registers get restored when the called function returns to the entry point,
   where a breakpoint is laying in wait.  */

void
generic_push_dummy_frame ()
{
  struct dummy_frame *dummy_frame;
  CORE_ADDR fp = (get_current_frame ())->frame;

  /* check to see if there are stale dummy frames, 
     perhaps left over from when a longjump took us out of a 
     function that was called by the debugger */

  dummy_frame = dummy_frame_stack;
  while (dummy_frame)
    if (INNER_THAN (dummy_frame->fp, fp))	/* stale -- destroy! */
      {
	dummy_frame_stack = dummy_frame->next;
	free (dummy_frame->registers);
	free (dummy_frame);
	dummy_frame = dummy_frame_stack;
      }
    else
      dummy_frame = dummy_frame->next;

  dummy_frame = xmalloc (sizeof (struct dummy_frame));
  dummy_frame->registers = xmalloc (REGISTER_BYTES);

  dummy_frame->pc = read_register (PC_REGNUM);
  dummy_frame->sp = read_register (SP_REGNUM);
  dummy_frame->top = dummy_frame->sp;
  dummy_frame->fp = fp;
  read_register_bytes (0, dummy_frame->registers, REGISTER_BYTES);
  dummy_frame->next = dummy_frame_stack;
  dummy_frame_stack = dummy_frame;
}

void
generic_save_dummy_frame_tos (sp)
     CORE_ADDR sp;
{
  dummy_frame_stack->top = sp;
}

/* Function: pop_frame
   Restore the machine state from either the saved dummy stack or a
   real stack frame. */

void
generic_pop_current_frame (pop)
     void (*pop) (struct frame_info * frame);
{
  struct frame_info *frame = get_current_frame ();
  if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
    generic_pop_dummy_frame ();
  else
    pop (frame);
}

/* Function: pop_dummy_frame
   Restore the machine state from a saved dummy stack frame. */

void
generic_pop_dummy_frame ()
{
  struct dummy_frame *dummy_frame = dummy_frame_stack;

  /* FIXME: what if the first frame isn't the right one, eg..
     because one call-by-hand function has done a longjmp into another one? */

  if (!dummy_frame)
    error ("Can't pop dummy frame!");
  dummy_frame_stack = dummy_frame->next;
  write_register_bytes (0, dummy_frame->registers, REGISTER_BYTES);
  flush_cached_frames ();

  free (dummy_frame->registers);
  free (dummy_frame);
}

/* Function: frame_chain_valid 
   Returns true for a user frame or a call_function_by_hand dummy frame,
   and false for the CRT0 start-up frame.  Purpose is to terminate backtrace */

int
generic_file_frame_chain_valid (fp, fi)
     CORE_ADDR fp;
     struct frame_info *fi;
{
  if (PC_IN_CALL_DUMMY (FRAME_SAVED_PC (fi), fp, fp))
    return 1;			/* don't prune CALL_DUMMY frames */
  else				/* fall back to default algorithm (see frame.h) */
    return (fp != 0
	    && (INNER_THAN (fi->frame, fp) || fi->frame == fp)
	    && !inside_entry_file (FRAME_SAVED_PC (fi)));
}

int
generic_func_frame_chain_valid (fp, fi)
     CORE_ADDR fp;
     struct frame_info *fi;
{
  if (PC_IN_CALL_DUMMY ((fi)->pc, fp, fp))
    return 1;			/* don't prune CALL_DUMMY frames */
  else				/* fall back to default algorithm (see frame.h) */
    return (fp != 0
	    && (INNER_THAN (fi->frame, fp) || fi->frame == fp)
	    && !inside_main_func ((fi)->pc)
	    && !inside_entry_func ((fi)->pc));
}

/* Function: fix_call_dummy
   Stub function.  Generic dumy frames typically do not need to fix
   the frame being created */

void
generic_fix_call_dummy (dummy, pc, fun, nargs, args, type, gcc_p)
     char *dummy;
     CORE_ADDR pc;
     CORE_ADDR fun;
     int nargs;
     struct value **args;
     struct type *type;
     int gcc_p;
{
  return;
}

/* Function: get_saved_register
   Find register number REGNUM relative to FRAME and put its (raw,
   target format) contents in *RAW_BUFFER.  

   Set *OPTIMIZED if the variable was optimized out (and thus can't be
   fetched).  Note that this is never set to anything other than zero
   in this implementation.

   Set *LVAL to lval_memory, lval_register, or not_lval, depending on
   whether the value was fetched from memory, from a register, or in a
   strange and non-modifiable way (e.g. a frame pointer which was
   calculated rather than fetched).  We will use not_lval for values
   fetched from generic dummy frames.

   Set *ADDRP to the address, either in memory on as a REGISTER_BYTE
   offset into the registers array.  If the value is stored in a dummy
   frame, set *ADDRP to zero.

   To use this implementation, define a function called
   "get_saved_register" in your target code, which simply passes all
   of its arguments to this function.

   The argument RAW_BUFFER must point to aligned memory.  */

void
generic_get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lval)
     char *raw_buffer;
     int *optimized;
     CORE_ADDR *addrp;
     struct frame_info *frame;
     int regnum;
     enum lval_type *lval;
{
  if (!target_has_registers)
    error ("No registers.");

  /* Normal systems don't optimize out things with register numbers.  */
  if (optimized != NULL)
    *optimized = 0;

  if (addrp)			/* default assumption: not found in memory */
    *addrp = 0;

  /* Note: since the current frame's registers could only have been
     saved by frames INTERIOR TO the current frame, we skip examining
     the current frame itself: otherwise, we would be getting the
     previous frame's registers which were saved by the current frame.  */

  while (frame && ((frame = frame->next) != NULL))
    {
      if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
	{
	  if (lval)		/* found it in a CALL_DUMMY frame */
	    *lval = not_lval;
	  if (raw_buffer)
	    memcpy (raw_buffer,
		    generic_find_dummy_frame (frame->pc, frame->frame) +
		    REGISTER_BYTE (regnum),
		    REGISTER_RAW_SIZE (regnum));
	  return;
	}

      FRAME_INIT_SAVED_REGS (frame);
      if (frame->saved_regs != NULL
	  && frame->saved_regs[regnum] != 0)
	{
	  if (lval)		/* found it saved on the stack */
	    *lval = lval_memory;
	  if (regnum == SP_REGNUM)
	    {
	      if (raw_buffer)	/* SP register treated specially */
		store_address (raw_buffer, REGISTER_RAW_SIZE (regnum),
			       frame->saved_regs[regnum]);
	    }
	  else
	    {
	      if (addrp)	/* any other register */
		*addrp = frame->saved_regs[regnum];
	      if (raw_buffer)
		read_memory (frame->saved_regs[regnum], raw_buffer,
			     REGISTER_RAW_SIZE (regnum));
	    }
	  return;
	}
    }

  /* If we get thru the loop to this point, it means the register was
     not saved in any frame.  Return the actual live-register value.  */

  if (lval)			/* found it in a live register */
    *lval = lval_register;
  if (addrp)
    *addrp = REGISTER_BYTE (regnum);
  if (raw_buffer)
    read_register_gen (regnum, raw_buffer);
}

void
_initialize_blockframe (void)
{
  obstack_init (&frame_cache_obstack);
}