summaryrefslogtreecommitdiff
path: root/libguile/stacks.c
blob: 16c851f6e78914c407a8db1d50c077f0c252f816 (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
/* Representation of stack frame debug information
 * Copyright (C) 1996,1997,2000,2001, 2006, 2007, 2008, 2009 Free Software Foundation
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */



#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "libguile/_scm.h"
#include "libguile/eval.h"
#include "libguile/debug.h"
#include "libguile/continuations.h"
#include "libguile/struct.h"
#include "libguile/macros.h"
#include "libguile/procprop.h"
#include "libguile/modules.h"
#include "libguile/root.h"
#include "libguile/strings.h"
#include "libguile/vm.h" /* to capture vm stacks */
#include "libguile/frames.h" /* vm frames */

#include "libguile/validate.h"
#include "libguile/stacks.h"
#include "libguile/private-options.h"



/* {Frames and stacks}
 *
 * The stack is represented as a struct with an id slot and a tail
 * array of scm_t_info_frame structs.
 *
 * A frame is represented as a pair where the car contains a stack and
 * the cdr an inum.  The inum is an index to the first SCM value of
 * the scm_t_info_frame struct.
 *
 * Stacks
 *   Constructor
 *     make-stack
 *   Selectors
 *     stack-id
 *     stack-ref
 *   Inspector
 *     stack-length
 *
 * Frames
 *   Constructor
 *     last-stack-frame
 *   Selectors
 *     frame-number
 *     frame-source
 *     frame-procedure
 *     frame-arguments
 *     frame-previous
 *     frame-next
 *   Predicates
 *     frame-real?
 *     frame-procedure?
 *     frame-evaluating-args?
 *     frame-overflow?  */



static SCM stack_id_with_fp (SCM vmframe, SCM **fp);

/* Count number of debug info frames on a stack, beginning with VMFRAME.
 */
static long
stack_depth (SCM vmframe, SCM *fp)
{
  long n;
  /* count vmframes, skipping boot frames */
  for (; scm_is_true (vmframe) && SCM_VM_FRAME_FP (vmframe) > fp;
       vmframe = scm_c_vm_frame_prev (vmframe))
    if (!SCM_PROGRAM_IS_BOOT (scm_vm_frame_program (vmframe)))
      ++n;
  return n;
}

/* Fill the scm_t_info_frame vector IFRAME with data from N stack frames
 * starting with the first stack frame represented by VMFRAME.
 */

static scm_t_bits
read_frames (SCM vmframe, long n, scm_t_info_frame *iframes)
{
  scm_t_info_frame *iframe = iframes;

  for (; scm_is_true (vmframe);
       vmframe = scm_c_vm_frame_prev (vmframe))
    {
      if (SCM_PROGRAM_IS_BOOT (scm_vm_frame_program (vmframe)))
        /* skip boot frame */
        continue;
      else 
        {
          /* Oh dear, oh dear, oh dear. */
          iframe->flags = SCM_UNPACK (SCM_INUM0) | SCM_FRAMEF_PROC;
          iframe->source = scm_vm_frame_source (vmframe);
          iframe->proc = scm_vm_frame_program (vmframe);
          iframe->args = scm_vm_frame_arguments (vmframe);
          ++iframe;
          if (--n == 0)
            break;
        }
    }
  return iframe - iframes;  /* Number of frames actually read */
}

/* Narrow STACK by cutting away stackframes (mutatingly).
 *
 * Inner frames (most recent) are cut by advancing the frames pointer.
 * Outer frames are cut by decreasing the recorded length.
 *
 * Cut maximally INNER inner frames and OUTER outer frames using
 * the keys INNER_KEY and OUTER_KEY.
 *
 * Frames are cut away starting at the end points and moving towards
 * the center of the stack.  The key is normally compared to the
 * operator in application frames.  Frames up to and including the key
 * are cut.
 *
 * If INNER_KEY is #t a different scheme is used for inner frames:
 *
 * Frames up to but excluding the first source frame originating from
 * a user module are cut, except for possible application frames
 * between the user frame and the last system frame previously
 * encountered.
 */

static void
narrow_stack (SCM stack, long inner, SCM inner_key, long outer, SCM outer_key)
{
  scm_t_stack *s = SCM_STACK (stack);
  unsigned long int i;
  long n = s->length;
  
  /* Cut inner part. */
  if (scm_is_eq (inner_key, SCM_BOOL_T))
    {
      /* Cut all frames up to user module code */
      for (i = 0; inner; ++i, --inner)
        ;
    }
  else
    /* Use standard cutting procedure. */
    {
      for (i = 0; inner; --inner)
	if (scm_is_eq (s->frames[i++].proc, inner_key))
	  break;
    }
  s->frames = &s->frames[i];
  n -= i;

  /* Cut outer part. */
  for (; n && outer; --outer)
    if (scm_is_eq (s->frames[--n].proc, outer_key))
      break;

  s->length = n;
}



/* Stacks
 */

SCM scm_stack_type;

SCM_DEFINE (scm_stack_p, "stack?", 1, 0, 0, 
            (SCM obj),
	    "Return @code{#t} if @var{obj} is a calling stack.")
#define FUNC_NAME s_scm_stack_p
{
  return scm_from_bool(SCM_STACKP (obj));
}
#undef FUNC_NAME

SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1, 
            (SCM obj, SCM args),
	    "Create a new stack. If @var{obj} is @code{#t}, the current\n"
	    "evaluation stack is used for creating the stack frames,\n"
	    "otherwise the frames are taken from @var{obj} (which must be\n"
	    "either a debug object or a continuation).\n\n"
	    "@var{args} should be a list containing any combination of\n"
	    "integer, procedure and @code{#t} values.\n\n"
	    "These values specify various ways of cutting away uninteresting\n"
	    "stack frames from the top and bottom of the stack that\n"
	    "@code{make-stack} returns.  They come in pairs like this:\n"
	    "@code{(@var{inner_cut_1} @var{outer_cut_1} @var{inner_cut_2}\n"
	    "@var{outer_cut_2} @dots{})}.\n\n"
	    "Each @var{inner_cut_N} can be @code{#t}, an integer, or a\n"
	    "procedure.  @code{#t} means to cut away all frames up to but\n"
	    "excluding the first user module frame.  An integer means to cut\n"
	    "away exactly that number of frames.  A procedure means to cut\n"
	    "away all frames up to but excluding the application frame whose\n"
	    "procedure matches the specified one.\n\n"
	    "Each @var{outer_cut_N} can be an integer or a procedure.  An\n"
	    "integer means to cut away that number of frames.  A procedure\n"
	    "means to cut away frames down to but excluding the application\n"
	    "frame whose procedure matches the specified one.\n\n"
	    "If the @var{outer_cut_N} of the last pair is missing, it is\n"
	    "taken as 0.")
#define FUNC_NAME s_scm_make_stack
{
  long n, size;
  int maxp;
  scm_t_info_frame *iframe;
  SCM vmframe;
  SCM stack;
  SCM id, *id_fp;
  SCM inner_cut, outer_cut;

  /* Extract a pointer to the innermost frame of whatever object
     scm_make_stack was given.  */
  if (scm_is_eq (obj, SCM_BOOL_T))
    {
      struct scm_vm *vp = SCM_VM_DATA (scm_the_vm ());
      vmframe = scm_c_make_vm_frame (scm_the_vm (), vp->fp, vp->sp, vp->ip, 0);
    }
  else if (SCM_VM_FRAME_P (obj))
    vmframe = obj;
  else if (SCM_CONTINUATIONP (obj))
    {
      scm_t_contregs *cont = SCM_CONTREGS (obj);
      if (!scm_is_null (cont->vm_conts))
        { SCM vm_cont;
          struct scm_vm_cont *data;
          vm_cont = scm_cdr (scm_car (cont->vm_conts));
          data = SCM_VM_CONT_DATA (vm_cont);
          vmframe = scm_c_make_vm_frame (vm_cont,
                                         data->fp + data->reloc,
                                         data->sp + data->reloc,
                                         data->ip,
                                         data->reloc);
        } else 
          vmframe = SCM_BOOL_F;
    }
  else
    {
      SCM_WRONG_TYPE_ARG (SCM_ARG1, obj);
      /* not reached */
    }

  if (scm_is_false (vmframe))
    return SCM_BOOL_F;

  /* Get ID of the stack corresponding to the given frame. */
  id = stack_id_with_fp (vmframe, &id_fp);

  /* Count number of frames.  Also get stack id tag and check whether
     there are more stackframes than we want to record
     (SCM_BACKTRACE_MAXDEPTH). */
  id = SCM_BOOL_F;
  maxp = 0;
  n = stack_depth (vmframe, id_fp);
  /* FIXME: redo maxp? */
  size = n * SCM_FRAME_N_SLOTS;

  /* Make the stack object. */
  stack = scm_make_struct (scm_stack_type, scm_from_long (size), SCM_EOL);
  SCM_STACK (stack) -> id = id;
  iframe = &SCM_STACK (stack) -> tail[0];
  SCM_STACK (stack) -> frames = iframe;
  SCM_STACK (stack) -> length = n;

  /* Translate the current chain of stack frames into debugging information. */
  n = read_frames (vmframe, n, iframe);
  if (n != SCM_STACK (stack)->length)
    {
      scm_puts ("warning: stack count incorrect!\n", scm_current_error_port ());
      SCM_STACK (stack)->length = n;
    }

  /* Narrow the stack according to the arguments given to scm_make_stack. */
  SCM_VALIDATE_REST_ARGUMENT (args);
  while (n > 0 && !scm_is_null (args))
    {
      inner_cut = SCM_CAR (args);
      args = SCM_CDR (args);
      if (scm_is_null (args)) 
	{
	  outer_cut = SCM_INUM0;
	} 
      else
	{
	  outer_cut = SCM_CAR (args);
	  args = SCM_CDR (args);
	}
      
      narrow_stack (stack,
		    scm_is_integer (inner_cut) ? scm_to_int (inner_cut) : n,
		    scm_is_integer (inner_cut) ? 0 : inner_cut,
		    scm_is_integer (outer_cut) ? scm_to_int (outer_cut) : n,
		    scm_is_integer (outer_cut) ? 0 : outer_cut);

      n = SCM_STACK (stack) -> length;
    }
  
  if (n > 0 && maxp)
    iframe[n - 1].flags |= SCM_FRAMEF_OVERFLOW;

  if (n > 0)
    return stack;
  else
    return SCM_BOOL_F;
}
#undef FUNC_NAME

SCM_DEFINE (scm_stack_id, "stack-id", 1, 0, 0, 
            (SCM stack),
	    "Return the identifier given to @var{stack} by @code{start-stack}.")
#define FUNC_NAME s_scm_stack_id
{
  SCM vmframe, *id_fp;
  
  if (scm_is_eq (stack, SCM_BOOL_T))
    {
      struct scm_vm *vp = SCM_VM_DATA (scm_the_vm ());
      vmframe = scm_c_make_vm_frame (scm_the_vm (), vp->fp, vp->sp, vp->ip, 0);
    }
  else if (SCM_VM_FRAME_P (stack))
    vmframe = stack;
  else if (SCM_CONTINUATIONP (stack))
    {
      scm_t_contregs *cont = SCM_CONTREGS (stack);
      if (!scm_is_null (cont->vm_conts))
        { SCM vm_cont;
          struct scm_vm_cont *data;
          vm_cont = scm_cdr (scm_car (cont->vm_conts));
          data = SCM_VM_CONT_DATA (vm_cont);
          vmframe = scm_c_make_vm_frame (vm_cont,
                                         data->fp + data->reloc,
                                         data->sp + data->reloc,
                                         data->ip,
                                         data->reloc);
        } else 
          vmframe = SCM_BOOL_F;
    }
  else
    {
      SCM_WRONG_TYPE_ARG (SCM_ARG1, stack);
      /* not reached */
    }

  return stack_id_with_fp (vmframe, &id_fp);
}
#undef FUNC_NAME

static SCM
stack_id_with_fp (SCM vmframe, SCM **fp)
{
  SCM holder = SCM_VM_FRAME_STACK_HOLDER (vmframe);

  if (SCM_VM_CONT_P (holder))
    {
      *fp = NULL;
      return SCM_BOOL_F;
    }
  else
    {
      *fp = NULL;
      return SCM_BOOL_F;
    }
}

SCM_DEFINE (scm_stack_ref, "stack-ref", 2, 0, 0,
            (SCM stack, SCM index),
	    "Return the @var{index}'th frame from @var{stack}.")
#define FUNC_NAME s_scm_stack_ref
{
  unsigned long int c_index;

  SCM_VALIDATE_STACK (1, stack);
  c_index = scm_to_unsigned_integer (index, 0, SCM_STACK_LENGTH(stack)-1);
  return scm_cons (stack, index);
}
#undef FUNC_NAME

SCM_DEFINE (scm_stack_length, "stack-length", 1, 0, 0, 
	    (SCM stack),
	    "Return the length of @var{stack}.")
#define FUNC_NAME s_scm_stack_length
{
  SCM_VALIDATE_STACK (1, stack);
  return scm_from_int (SCM_STACK_LENGTH (stack));
}
#undef FUNC_NAME

/* Frames
 */

SCM_DEFINE (scm_frame_p, "frame?", 1, 0, 0, 
            (SCM obj),
	    "Return @code{#t} if @var{obj} is a stack frame.")
#define FUNC_NAME s_scm_frame_p
{
  return scm_from_bool(SCM_FRAMEP (obj));
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_number, "frame-number", 1, 0, 0, 
	    (SCM frame),
	    "Return the frame number of @var{frame}.")
#define FUNC_NAME s_scm_frame_number
{
  SCM_VALIDATE_FRAME (1, frame);
  return scm_from_int (SCM_FRAME_NUMBER (frame));
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_source, "frame-source", 1, 0, 0, 
	    (SCM frame),
	    "Return the source of @var{frame}.")
#define FUNC_NAME s_scm_frame_source
{
  SCM_VALIDATE_FRAME (1, frame);
  return SCM_FRAME_SOURCE (frame);
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_procedure, "frame-procedure", 1, 0, 0, 
	    (SCM frame),
	    "Return the procedure for @var{frame}, or @code{#f} if no\n"
	    "procedure is associated with @var{frame}.")
#define FUNC_NAME s_scm_frame_procedure
{
  SCM_VALIDATE_FRAME (1, frame);
  return (SCM_FRAME_PROC_P (frame)
	  ? SCM_FRAME_PROC (frame)
	  : SCM_BOOL_F);
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_arguments, "frame-arguments", 1, 0, 0, 
	    (SCM frame),
	    "Return the arguments of @var{frame}.")
#define FUNC_NAME s_scm_frame_arguments
{
  SCM_VALIDATE_FRAME (1, frame);
  return SCM_FRAME_ARGS (frame);
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_previous, "frame-previous", 1, 0, 0, 
	    (SCM frame),
	    "Return the previous frame of @var{frame}, or @code{#f} if\n"
	    "@var{frame} is the first frame in its stack.")
#define FUNC_NAME s_scm_frame_previous
{
  unsigned long int n;
  SCM_VALIDATE_FRAME (1, frame);
  n = scm_to_ulong (SCM_CDR (frame)) + 1;
  if (n >= SCM_STACK_LENGTH (SCM_CAR (frame)))
    return SCM_BOOL_F;
  else
    return scm_cons (SCM_CAR (frame), scm_from_ulong (n));
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_next, "frame-next", 1, 0, 0, 
           (SCM frame),
	    "Return the next frame of @var{frame}, or @code{#f} if\n"
	    "@var{frame} is the last frame in its stack.")
#define FUNC_NAME s_scm_frame_next
{
  unsigned long int n;
  SCM_VALIDATE_FRAME (1, frame);
  n = scm_to_ulong (SCM_CDR (frame));
  if (n == 0)
    return SCM_BOOL_F;
  else
    return scm_cons (SCM_CAR (frame), scm_from_ulong (n - 1));
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_real_p, "frame-real?", 1, 0, 0, 
	    (SCM frame),
	    "Return @code{#t} if @var{frame} is a real frame.")
#define FUNC_NAME s_scm_frame_real_p
{
  SCM_VALIDATE_FRAME (1, frame);
  return scm_from_bool(SCM_FRAME_REAL_P (frame));
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_procedure_p, "frame-procedure?", 1, 0, 0, 
	    (SCM frame),
	    "Return @code{#t} if a procedure is associated with @var{frame}.")
#define FUNC_NAME s_scm_frame_procedure_p
{
  SCM_VALIDATE_FRAME (1, frame);
  return scm_from_bool(SCM_FRAME_PROC_P (frame));
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_evaluating_args_p, "frame-evaluating-args?", 1, 0, 0, 
	    (SCM frame),
	    "Return @code{#t} if @var{frame} contains evaluated arguments.")
#define FUNC_NAME s_scm_frame_evaluating_args_p
{
  SCM_VALIDATE_FRAME (1, frame);
  return scm_from_bool(SCM_FRAME_EVAL_ARGS_P (frame));
}
#undef FUNC_NAME

SCM_DEFINE (scm_frame_overflow_p, "frame-overflow?", 1, 0, 0, 
	    (SCM frame),
	    "Return @code{#t} if @var{frame} is an overflow frame.")
#define FUNC_NAME s_scm_frame_overflow_p
{
  SCM_VALIDATE_FRAME (1, frame);
  return scm_from_bool(SCM_FRAME_OVERFLOW_P (frame));
}
#undef FUNC_NAME



void
scm_init_stacks ()
{
  scm_stack_type =
    scm_permanent_object
    (scm_make_vtable (scm_from_locale_string (SCM_STACK_LAYOUT),
                      SCM_UNDEFINED));
  scm_set_struct_vtable_name_x (scm_stack_type,
				scm_from_locale_symbol ("stack"));
#include "libguile/stacks.x"
}

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/