aboutsummaryrefslogtreecommitdiff
path: root/gdb/guile/scm-frame.c
blob: 7b539677ffdf4cc0e82c65d36a9a2d191a9b0f0a (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
/* Scheme interface to stack frames.

   Copyright (C) 2008-2018 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/>.  */

/* See README file in this directory for implementation notes, coding
   conventions, et.al.  */

#include "defs.h"
#include "block.h"
#include "frame.h"
#include "inferior.h"
#include "objfiles.h"
#include "symfile.h"
#include "symtab.h"
#include "stack.h"
#include "user-regs.h"
#include "value.h"
#include "guile-internal.h"

/* The <gdb:frame> smob.
   The typedef for this struct is in guile-internal.h.  */

struct _frame_smob
{
  /* This always appears first.  */
  eqable_gdb_smob base;

  struct frame_id frame_id;
  struct gdbarch *gdbarch;

  /* Frames are tracked by inferior.
     We need some place to put the eq?-able hash table, and this feels as
     good a place as any.  Frames in one inferior shouldn't be considered
     equal to frames in a different inferior.  The frame becomes invalid if
     this becomes NULL (the inferior has been deleted from gdb).
     It's easier to relax restrictions than impose them after the fact.
     N.B. It is an outstanding question whether a frame survives reruns of
     the inferior.  Intuitively the answer is "No", but currently a frame
     also survives, e.g., multiple invocations of the same function from
     the same point.  Even different threads can have the same frame, e.g.,
     if a thread dies and a new thread gets the same stack.  */
  struct inferior *inferior;

  /* Marks that the FRAME_ID member actually holds the ID of the frame next
     to this, and not this frame's ID itself.  This is a hack to permit Scheme
     frame objects which represent invalid frames (i.e., the last frame_info
     in a corrupt stack).  The problem arises from the fact that this code
     relies on FRAME_ID to uniquely identify a frame, which is not always true
     for the last "frame" in a corrupt stack (it can have a null ID, or the
     same ID as the  previous frame).  Whenever get_prev_frame returns NULL, we
     record the frame_id of the next frame and set FRAME_ID_IS_NEXT to 1.  */
  int frame_id_is_next;
};

static const char frame_smob_name[] = "gdb:frame";

/* The tag Guile knows the frame smob by.  */
static scm_t_bits frame_smob_tag;

/* Keywords used in argument passing.  */
static SCM block_keyword;

static const struct inferior_data *frscm_inferior_data_key;

/* Administrivia for frame smobs.  */

/* Helper function to hash a frame_smob.  */

static hashval_t
frscm_hash_frame_smob (const void *p)
{
  const frame_smob *f_smob = (const frame_smob *) p;
  const struct frame_id *fid = &f_smob->frame_id;
  hashval_t hash = htab_hash_pointer (f_smob->inferior);

  if (fid->stack_status == FID_STACK_VALID)
    hash = iterative_hash (&fid->stack_addr, sizeof (fid->stack_addr), hash);
  if (fid->code_addr_p)
    hash = iterative_hash (&fid->code_addr, sizeof (fid->code_addr), hash);
  if (fid->special_addr_p)
    hash = iterative_hash (&fid->special_addr, sizeof (fid->special_addr),
			   hash);

  return hash;
}

/* Helper function to compute equality of frame_smobs.  */

static int
frscm_eq_frame_smob (const void *ap, const void *bp)
{
  const frame_smob *a = (const frame_smob *) ap;
  const frame_smob *b = (const frame_smob *) bp;

  return (frame_id_eq (a->frame_id, b->frame_id)
	  && a->inferior == b->inferior
	  && a->inferior != NULL);
}

/* Return the frame -> SCM mapping table.
   It is created if necessary.  */

static htab_t
frscm_inferior_frame_map (struct inferior *inferior)
{
  htab_t htab = (htab_t) inferior_data (inferior, frscm_inferior_data_key);

  if (htab == NULL)
    {
      htab = gdbscm_create_eqable_gsmob_ptr_map (frscm_hash_frame_smob,
						 frscm_eq_frame_smob);
      set_inferior_data (inferior, frscm_inferior_data_key, htab);
    }

  return htab;
}

/* The smob "free" function for <gdb:frame>.  */

static size_t
frscm_free_frame_smob (SCM self)
{
  frame_smob *f_smob = (frame_smob *) SCM_SMOB_DATA (self);

  if (f_smob->inferior != NULL)
    {
      htab_t htab = frscm_inferior_frame_map (f_smob->inferior);

      gdbscm_clear_eqable_gsmob_ptr_slot (htab, &f_smob->base);
    }

  /* Not necessary, done to catch bugs.  */
  f_smob->inferior = NULL;

  return 0;
}

/* The smob "print" function for <gdb:frame>.  */

static int
frscm_print_frame_smob (SCM self, SCM port, scm_print_state *pstate)
{
  frame_smob *f_smob = (frame_smob *) SCM_SMOB_DATA (self);

  gdbscm_printf (port, "#<%s ", frame_smob_name);

  string_file strfile;
  fprint_frame_id (&strfile, f_smob->frame_id);
  gdbscm_printf (port, "%s", strfile.c_str ());

  scm_puts (">", port);

  scm_remember_upto_here_1 (self);

  /* Non-zero means success.  */
  return 1;
}

/* Low level routine to create a <gdb:frame> object.  */

static SCM
frscm_make_frame_smob (void)
{
  frame_smob *f_smob = (frame_smob *)
    scm_gc_malloc (sizeof (frame_smob), frame_smob_name);
  SCM f_scm;

  f_smob->frame_id = null_frame_id;
  f_smob->gdbarch = NULL;
  f_smob->inferior = NULL;
  f_smob->frame_id_is_next = 0;
  f_scm = scm_new_smob (frame_smob_tag, (scm_t_bits) f_smob);
  gdbscm_init_eqable_gsmob (&f_smob->base, f_scm);

  return f_scm;
}

/* Return non-zero if SCM is a <gdb:frame> object.  */

int
frscm_is_frame (SCM scm)
{
  return SCM_SMOB_PREDICATE (frame_smob_tag, scm);
}

/* (frame? object) -> boolean */

static SCM
gdbscm_frame_p (SCM scm)
{
  return scm_from_bool (frscm_is_frame (scm));
}

/* Create a new <gdb:frame> object that encapsulates FRAME.
   Returns a <gdb:exception> object if there is an error.  */

static SCM
frscm_scm_from_frame (struct frame_info *frame, struct inferior *inferior)
{
  frame_smob *f_smob, f_smob_for_lookup;
  SCM f_scm;
  htab_t htab;
  eqable_gdb_smob **slot;
  struct frame_id frame_id = null_frame_id;
  struct gdbarch *gdbarch = NULL;
  int frame_id_is_next = 0;

  /* If we've already created a gsmob for this frame, return it.
     This makes frames eq?-able.  */
  htab = frscm_inferior_frame_map (inferior);
  f_smob_for_lookup.frame_id = get_frame_id (frame);
  f_smob_for_lookup.inferior = inferior;
  slot = gdbscm_find_eqable_gsmob_ptr_slot (htab, &f_smob_for_lookup.base);
  if (*slot != NULL)
    return (*slot)->containing_scm;

  TRY
    {
      /* Try to get the previous frame, to determine if this is the last frame
	 in a corrupt stack.  If so, we need to store the frame_id of the next
	 frame and not of this one (which is possibly invalid).  */
      if (get_prev_frame (frame) == NULL
	  && get_frame_unwind_stop_reason (frame) != UNWIND_NO_REASON
	  && get_next_frame (frame) != NULL)
	{
	  frame_id = get_frame_id (get_next_frame (frame));
	  frame_id_is_next = 1;
	}
      else
	{
	  frame_id = get_frame_id (frame);
	  frame_id_is_next = 0;
	}
      gdbarch = get_frame_arch (frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      return gdbscm_scm_from_gdb_exception (except);
    }
  END_CATCH

  f_scm = frscm_make_frame_smob ();
  f_smob = (frame_smob *) SCM_SMOB_DATA (f_scm);
  f_smob->frame_id = frame_id;
  f_smob->gdbarch = gdbarch;
  f_smob->inferior = inferior;
  f_smob->frame_id_is_next = frame_id_is_next;

  gdbscm_fill_eqable_gsmob_ptr_slot (slot, &f_smob->base);

  return f_scm;
}

/* Create a new <gdb:frame> object that encapsulates FRAME.
   A Scheme exception is thrown if there is an error.  */

static SCM
frscm_scm_from_frame_unsafe (struct frame_info *frame,
			     struct inferior *inferior)
{
  SCM f_scm = frscm_scm_from_frame (frame, inferior);

  if (gdbscm_is_exception (f_scm))
    gdbscm_throw (f_scm);

  return f_scm;
}

/* Returns the <gdb:frame> object in SELF.
   Throws an exception if SELF is not a <gdb:frame> object.  */

static SCM
frscm_get_frame_arg_unsafe (SCM self, int arg_pos, const char *func_name)
{
  SCM_ASSERT_TYPE (frscm_is_frame (self), self, arg_pos, func_name,
		   frame_smob_name);

  return self;
}

/* There is no gdbscm_scm_to_frame function because translating
   a frame SCM object to a struct frame_info * can throw a GDB error.
   Thus code working with frames has to handle both Scheme errors (e.g., the
   object is not a frame) and GDB errors (e.g., the frame lookup failed).

   To help keep things clear we split what would be gdbscm_scm_to_frame
   into two:

   frscm_get_frame_smob_arg_unsafe
     - throws a Scheme error if object is not a frame,
       or if the inferior is gone or is no longer current

   frscm_frame_smob_to_frame
     - may throw a gdb error if the conversion fails
     - it's not clear when it will and won't throw a GDB error,
       but for robustness' sake we assume that whenever we call out to GDB
       a GDB error may get thrown (and thus the call must be wrapped in a
       TRY_CATCH)  */

/* Returns the frame_smob for the object wrapped by FRAME_SCM.
   A Scheme error is thrown if FRAME_SCM is not a frame.  */

frame_smob *
frscm_get_frame_smob_arg_unsafe (SCM self, int arg_pos, const char *func_name)
{
  SCM f_scm = frscm_get_frame_arg_unsafe (self, arg_pos, func_name);
  frame_smob *f_smob = (frame_smob *) SCM_SMOB_DATA (f_scm);

  if (f_smob->inferior == NULL)
    {
      gdbscm_invalid_object_error (func_name, arg_pos, self,
				   _("inferior"));
    }
  if (f_smob->inferior != current_inferior ())
    scm_misc_error (func_name, _("inferior has changed"), SCM_EOL);

  return f_smob;
}

/* Returns the frame_info object wrapped by F_SMOB.
   If the frame doesn't exist anymore (the frame id doesn't
   correspond to any frame in the inferior), returns NULL.
   This function calls GDB routines, so don't assume a GDB error will
   not be thrown.  */

struct frame_info *
frscm_frame_smob_to_frame (frame_smob *f_smob)
{
  struct frame_info *frame;

  frame = frame_find_by_id (f_smob->frame_id);
  if (frame == NULL)
    return NULL;

  if (f_smob->frame_id_is_next)
    frame = get_prev_frame (frame);

  return frame;
}

/* Helper function for frscm_del_inferior_frames to mark the frame
   as invalid.  */

static int
frscm_mark_frame_invalid (void **slot, void *info)
{
  frame_smob *f_smob = (frame_smob *) *slot;

  f_smob->inferior = NULL;
  return 1;
}

/* This function is called when an inferior is about to be freed.
   Invalidate the frame as further actions on the frame could result
   in bad data.  All access to the frame should be gated by
   frscm_get_frame_smob_arg_unsafe which will raise an exception on
   invalid frames.  */

static void
frscm_del_inferior_frames (struct inferior *inferior, void *datum)
{
  htab_t htab = (htab_t) datum;

  if (htab != NULL)
    {
      htab_traverse_noresize (htab, frscm_mark_frame_invalid, NULL);
      htab_delete (htab);
    }
}

/* Frame methods.  */

/* (frame-valid? <gdb:frame>) -> bool
   Returns #t if the frame corresponding to the frame_id of this
   object still exists in the inferior.  */

static SCM
gdbscm_frame_valid_p (SCM self)
{
  frame_smob *f_smob;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  return scm_from_bool (frame != NULL);
}

/* (frame-name <gdb:frame>) -> string
   Returns the name of the function corresponding to this frame,
   or #f if there is no function.  */

static SCM
gdbscm_frame_name (SCM self)
{
  frame_smob *f_smob;
  gdb::unique_xmalloc_ptr<char> name;
  enum language lang = language_minimal;
  struct frame_info *frame = NULL;
  SCM result;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	name = find_frame_funname (frame, &lang, NULL);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  if (name != NULL)
    result = gdbscm_scm_from_c_string (name.get ());
  else
    result = SCM_BOOL_F;

  return result;
}

/* (frame-type <gdb:frame>) -> integer
   Returns the frame type, namely one of the gdb:*_FRAME constants.  */

static SCM
gdbscm_frame_type (SCM self)
{
  frame_smob *f_smob;
  enum frame_type type = NORMAL_FRAME;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	type = get_frame_type (frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  return scm_from_int (type);
}

/* (frame-arch <gdb:frame>) -> <gdb:architecture>
   Returns the frame's architecture as a gdb:architecture object.  */

static SCM
gdbscm_frame_arch (SCM self)
{
  frame_smob *f_smob;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  return arscm_scm_from_arch (f_smob->gdbarch);
}

/* (frame-unwind-stop-reason <gdb:frame>) -> integer
   Returns one of the gdb:FRAME_UNWIND_* constants.  */

static SCM
gdbscm_frame_unwind_stop_reason (SCM self)
{
  frame_smob *f_smob;
  struct frame_info *frame = NULL;
  enum unwind_stop_reason stop_reason;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  stop_reason = get_frame_unwind_stop_reason (frame);

  return scm_from_int (stop_reason);
}

/* (frame-pc <gdb:frame>) -> integer
   Returns the frame's resume address.  */

static SCM
gdbscm_frame_pc (SCM self)
{
  frame_smob *f_smob;
  CORE_ADDR pc = 0;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	pc = get_frame_pc (frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  return gdbscm_scm_from_ulongest (pc);
}

/* (frame-block <gdb:frame>) -> <gdb:block>
   Returns the frame's code block, or #f if one cannot be found.  */

static SCM
gdbscm_frame_block (SCM self)
{
  frame_smob *f_smob;
  const struct block *block = NULL, *fn_block;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	block = get_frame_block (frame, NULL);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  for (fn_block = block;
       fn_block != NULL && BLOCK_FUNCTION (fn_block) == NULL;
       fn_block = BLOCK_SUPERBLOCK (fn_block))
    continue;

  if (block == NULL || fn_block == NULL || BLOCK_FUNCTION (fn_block) == NULL)
    {
      scm_misc_error (FUNC_NAME, _("cannot find block for frame"),
		      scm_list_1 (self));
    }

  if (block != NULL)
    {
      return bkscm_scm_from_block
	(block, symbol_objfile (BLOCK_FUNCTION (fn_block)));
    }

  return SCM_BOOL_F;
}

/* (frame-function <gdb:frame>) -> <gdb:symbol>
   Returns the symbol for the function corresponding to this frame,
   or #f if there isn't one.  */

static SCM
gdbscm_frame_function (SCM self)
{
  frame_smob *f_smob;
  struct symbol *sym = NULL;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	sym = find_pc_function (get_frame_address_in_block (frame));
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

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

  return SCM_BOOL_F;
}

/* (frame-older <gdb:frame>) -> <gdb:frame>
   Returns the frame immediately older (outer) to this frame,
   or #f if there isn't one.  */

static SCM
gdbscm_frame_older (SCM self)
{
  frame_smob *f_smob;
  struct frame_info *prev = NULL;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	prev = get_prev_frame (frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  if (prev != NULL)
    return frscm_scm_from_frame_unsafe (prev, f_smob->inferior);

  return SCM_BOOL_F;
}

/* (frame-newer <gdb:frame>) -> <gdb:frame>
   Returns the frame immediately newer (inner) to this frame,
   or #f if there isn't one.  */

static SCM
gdbscm_frame_newer (SCM self)
{
  frame_smob *f_smob;
  struct frame_info *next = NULL;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	next = get_next_frame (frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  if (next != NULL)
    return frscm_scm_from_frame_unsafe (next, f_smob->inferior);

  return SCM_BOOL_F;
}

/* (frame-sal <gdb:frame>) -> <gdb:sal>
   Returns the frame's symtab and line.  */

static SCM
gdbscm_frame_sal (SCM self)
{
  frame_smob *f_smob;
  struct symtab_and_line sal;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	sal = find_frame_sal (frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  return stscm_scm_from_sal (sal);
}

/* (frame-read-register <gdb:frame> string) -> <gdb:value>
   The register argument must be a string.  */

static SCM
gdbscm_frame_read_register (SCM self, SCM register_scm)
{
  char *register_str;
  struct value *value = NULL;
  struct frame_info *frame = NULL;
  struct cleanup *cleanup;
  frame_smob *f_smob;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);
  gdbscm_parse_function_args (FUNC_NAME, SCM_ARG2, NULL, "s",
			      register_scm, &register_str);
  cleanup = make_cleanup (xfree, register_str);

  TRY
    {
      int regnum;

      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame)
	{
	  regnum = user_reg_map_name_to_regnum (get_frame_arch (frame),
						register_str,
						strlen (register_str));
	  if (regnum >= 0)
	    value = value_of_register (regnum, frame);
	}
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  do_cleanups (cleanup);

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  if (value == NULL)
    {
      gdbscm_out_of_range_error (FUNC_NAME, SCM_ARG2, register_scm,
				 _("unknown register"));
    }

  return vlscm_scm_from_value (value);
}

/* (frame-read-var <gdb:frame> <gdb:symbol>) -> <gdb:value>
   (frame-read-var <gdb:frame> string [#:block <gdb:block>]) -> <gdb:value>
   If the optional block argument is provided start the search from that block,
   otherwise search from the frame's current block (determined by examining
   the resume address of the frame).  The variable argument must be a string
   or an instance of a <gdb:symbol>.  The block argument must be an instance of
   <gdb:block>.  */

static SCM
gdbscm_frame_read_var (SCM self, SCM symbol_scm, SCM rest)
{
  SCM keywords[] = { block_keyword, SCM_BOOL_F };
  frame_smob *f_smob;
  int block_arg_pos = -1;
  SCM block_scm = SCM_UNDEFINED;
  struct frame_info *frame = NULL;
  struct symbol *var = NULL;
  const struct block *block = NULL;
  struct value *value = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  gdbscm_parse_function_args (FUNC_NAME, SCM_ARG3, keywords, "#O",
			      rest, &block_arg_pos, &block_scm);

  if (syscm_is_symbol (symbol_scm))
    {
      var = syscm_get_valid_symbol_arg_unsafe (symbol_scm, SCM_ARG2,
					       FUNC_NAME);
      SCM_ASSERT (SCM_UNBNDP (block_scm), block_scm, SCM_ARG3, FUNC_NAME);
    }
  else if (scm_is_string (symbol_scm))
    {
      const struct block *block = NULL;
      struct cleanup *cleanup;
      struct gdb_exception except = exception_none;

      if (! SCM_UNBNDP (block_scm))
	{
	  SCM except_scm;

	  gdb_assert (block_arg_pos > 0);
	  block = bkscm_scm_to_block (block_scm, block_arg_pos, FUNC_NAME,
				      &except_scm);
	  if (block == NULL)
	    gdbscm_throw (except_scm);
	}

      {
	gdb::unique_xmalloc_ptr<char> var_name
	  (gdbscm_scm_to_c_string (symbol_scm));
	/* N.B. Between here and the end of the scope, don't do anything
	   to cause a Scheme exception.  */

	TRY
	  {
	    struct block_symbol lookup_sym;

	    if (block == NULL)
	      block = get_frame_block (frame, NULL);
	    lookup_sym = lookup_symbol (var_name.get (), block, VAR_DOMAIN,
					NULL);
	    var = lookup_sym.symbol;
	    block = lookup_sym.block;
	  }
	CATCH (ex, RETURN_MASK_ALL)
	  {
	    except = ex;
	  }
	END_CATCH
      }

      GDBSCM_HANDLE_GDB_EXCEPTION (except);

      if (var == NULL)
	gdbscm_out_of_range_error (FUNC_NAME, 0, symbol_scm,
				   _("variable not found"));
    }
  else
    {
      /* Use SCM_ASSERT_TYPE for more consistent error messages.  */
      SCM_ASSERT_TYPE (0, symbol_scm, SCM_ARG1, FUNC_NAME,
		       _("gdb:symbol or string"));
    }

  TRY
    {
      value = read_var_value (var, block, frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  return vlscm_scm_from_value (value);
}

/* (frame-select <gdb:frame>) -> unspecified
   Select this frame.  */

static SCM
gdbscm_frame_select (SCM self)
{
  frame_smob *f_smob;
  struct frame_info *frame = NULL;

  f_smob = frscm_get_frame_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);

  TRY
    {
      frame = frscm_frame_smob_to_frame (f_smob);
      if (frame != NULL)
	select_frame (frame);
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  if (frame == NULL)
    {
      gdbscm_invalid_object_error (FUNC_NAME, SCM_ARG1, self,
				   _("<gdb:frame>"));
    }

  return SCM_UNSPECIFIED;
}

/* (newest-frame) -> <gdb:frame>
   Returns the newest frame.  */

static SCM
gdbscm_newest_frame (void)
{
  struct frame_info *frame = NULL;

  TRY
    {
      frame = get_current_frame ();
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  return frscm_scm_from_frame_unsafe (frame, current_inferior ());
}

/* (selected-frame) -> <gdb:frame>
   Returns the selected frame.  */

static SCM
gdbscm_selected_frame (void)
{
  struct frame_info *frame = NULL;

  TRY
    {
      frame = get_selected_frame (_("No frame is currently selected"));
    }
  CATCH (except, RETURN_MASK_ALL)
    {
      GDBSCM_HANDLE_GDB_EXCEPTION (except);
    }
  END_CATCH

  return frscm_scm_from_frame_unsafe (frame, current_inferior ());
}

/* (unwind-stop-reason-string integer) -> string
   Return a string explaining the unwind stop reason.  */

static SCM
gdbscm_unwind_stop_reason_string (SCM reason_scm)
{
  int reason;
  const char *str;

  gdbscm_parse_function_args (FUNC_NAME, SCM_ARG1, NULL, "i",
			      reason_scm, &reason);

  if (reason < UNWIND_FIRST || reason > UNWIND_LAST)
    scm_out_of_range (FUNC_NAME, reason_scm);

  str = unwind_stop_reason_to_string ((enum unwind_stop_reason) reason);
  return gdbscm_scm_from_c_string (str);
}

/* Initialize the Scheme frame support.  */

static const scheme_integer_constant frame_integer_constants[] =
{
#define ENTRY(X) { #X, X }

  ENTRY (NORMAL_FRAME),
  ENTRY (DUMMY_FRAME),
  ENTRY (INLINE_FRAME),
  ENTRY (TAILCALL_FRAME),
  ENTRY (SIGTRAMP_FRAME),
  ENTRY (ARCH_FRAME),
  ENTRY (SENTINEL_FRAME),

#undef ENTRY

#define SET(name, description) \
  { "FRAME_" #name, name },
#include "unwind_stop_reasons.def"
#undef SET

  END_INTEGER_CONSTANTS
};

static const scheme_function frame_functions[] =
{
  { "frame?", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_p),
    "\
Return #t if the object is a <gdb:frame> object." },

  { "frame-valid?", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_valid_p),
    "\
Return #t if the object is a valid <gdb:frame> object.\n\
Frames become invalid when the inferior returns to its caller." },

  { "frame-name", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_name),
    "\
Return the name of the function corresponding to this frame,\n\
or #f if there is no function." },

  { "frame-arch", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_arch),
    "\
Return the frame's architecture as a <gdb:arch> object." },

  { "frame-type", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_type),
    "\
Return the frame type, namely one of the gdb:*_FRAME constants." },

  { "frame-unwind-stop-reason", 1, 0, 0,
    as_a_scm_t_subr (gdbscm_frame_unwind_stop_reason),
    "\
Return one of the gdb:FRAME_UNWIND_* constants explaining why\n\
it's not possible to find frames older than this." },

  { "frame-pc", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_pc),
    "\
Return the frame's resume address." },

  { "frame-block", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_block),
    "\
Return the frame's code block, or #f if one cannot be found." },

  { "frame-function", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_function),
    "\
Return the <gdb:symbol> for the function corresponding to this frame,\n\
or #f if there isn't one." },

  { "frame-older", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_older),
    "\
Return the frame immediately older (outer) to this frame,\n\
or #f if there isn't one." },

  { "frame-newer", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_newer),
    "\
Return the frame immediately newer (inner) to this frame,\n\
or #f if there isn't one." },

  { "frame-sal", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_sal),
    "\
Return the frame's symtab-and-line <gdb:sal> object." },

  { "frame-read-var", 2, 0, 1, as_a_scm_t_subr (gdbscm_frame_read_var),
    "\
Return the value of the symbol in the frame.\n\
\n\
  Arguments: <gdb:frame> <gdb:symbol>\n\
         Or: <gdb:frame> string [#:block <gdb:block>]" },

  { "frame-read-register", 2, 0, 0,
    as_a_scm_t_subr (gdbscm_frame_read_register),
    "\
Return the value of the register in the frame.\n\
\n\
  Arguments: <gdb:frame> string" },

  { "frame-select", 1, 0, 0, as_a_scm_t_subr (gdbscm_frame_select),
    "\
Select this frame." },

  { "newest-frame", 0, 0, 0, as_a_scm_t_subr (gdbscm_newest_frame),
    "\
Return the newest frame." },

  { "selected-frame", 0, 0, 0, as_a_scm_t_subr (gdbscm_selected_frame),
    "\
Return the selected frame." },

  { "unwind-stop-reason-string", 1, 0, 0,
    as_a_scm_t_subr (gdbscm_unwind_stop_reason_string),
    "\
Return a string explaining the unwind stop reason.\n\
\n\
  Arguments: integer (the result of frame-unwind-stop-reason)" },

  END_FUNCTIONS
};

void
gdbscm_initialize_frames (void)
{
  frame_smob_tag
    = gdbscm_make_smob_type (frame_smob_name, sizeof (frame_smob));
  scm_set_smob_free (frame_smob_tag, frscm_free_frame_smob);
  scm_set_smob_print (frame_smob_tag, frscm_print_frame_smob);

  gdbscm_define_integer_constants (frame_integer_constants, 1);
  gdbscm_define_functions (frame_functions, 1);

  block_keyword = scm_from_latin1_keyword ("block");

  /* Register an inferior "free" callback so we can properly
     invalidate frames when an inferior file is about to be deleted.  */
  frscm_inferior_data_key
    = register_inferior_data_with_cleanup (NULL, frscm_del_inferior_frames);
}