aboutsummaryrefslogtreecommitdiff
path: root/gdb/blockframe.c
blob: c1af2806e2ed1c1f8f0c91dd41df1dc518bb3cc8 (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
/* Get info from stack frames;
   convert between frames, blocks, functions and pc values.
   Copyright 1986, 1987, 1988, 1989, 1991 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., 675 Mass Ave, Cambridge, MA 02139, 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 */

/* 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.  */
  if (PC_IN_CALL_DUMMY (addr, 0, 0))
    return 0;
#endif
  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;
  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.  */
  if (PC_IN_CALL_DUMMY (pc, 0, 0))
    return 0;
#endif
  return (symfile_objfile -> ei.entry_func_lowpc  <= pc &&
	  symfile_objfile -> ei.entry_func_highpc > pc);
}

/* Address of innermost stack frame (contents of FP register) */

static FRAME 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.
 */
struct obstack frame_cache_obstack;

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

FRAME
get_current_frame ()
{
  /* We assume its address is kept in a general register;
     param.h says which register.  */

  return current_frame;
}

void
set_current_frame (frame)
     FRAME frame;
{
  current_frame = frame;
}

FRAME
create_new_frame (addr, pc)
     FRAME_ADDR addr;
     CORE_ADDR pc;
{
  struct frame_info *fci;	/* Same type as FRAME */
  char *name;

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

  /* Arbitrary frame */
  fci->next = (struct frame_info *) 0;
  fci->prev = (struct frame_info *) 0;
  fci->frame = addr;
  fci->pc = pc;
  find_pc_partial_function (pc, &name, (CORE_ADDR *)NULL,(CORE_ADDR *)NULL);
  fci->signal_handler_caller = IN_SIGTRAMP (fci->pc, name);

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

  return fci;
}

/* Return the frame that called FRAME.
   If FRAME is the original frame (it has no caller), return 0.  */

FRAME
get_prev_frame (frame)
     FRAME frame;
{
  /* We're allowed to know that FRAME and "struct frame_info *" are
     the same */
  return get_prev_frame_info (frame);
}

/* Return the frame that FRAME calls (0 if FRAME is the innermost
   frame).  */

FRAME
get_next_frame (frame)
     FRAME frame;
{
  /* We're allowed to know that FRAME and "struct frame_info *" are
     the same */
  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 = (struct frame_info *) 0; /* Invalidate cache */
}

/* Flush the frame cache, and start a new one if necessary.  */
void
reinit_frame_cache ()
{
  flush_cached_frames ();
  if (target_has_stack)
    {
      set_current_frame (create_new_frame (read_fp (), read_pc ()));
      select_frame (get_current_frame (), 0);
    }
  else
    {
      set_current_frame (0);
      select_frame ((FRAME) 0, -1);
    }
}

/* Return a structure containing various interesting information
   about a specified stack frame.  */
/* How do I justify including this function?  Well, the FRAME
   identifier format has gone through several changes recently, and
   it's not completely inconceivable that it could happen again.  If
   it does, have this routine around will help */

struct frame_info *
get_frame_info (frame)
     FRAME frame;
{
  return frame;
}

/* If a machine allows frameless functions, it should define a macro
   FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) in param.h.  FI is the struct
   frame_info for the frame, and FRAMELESS should be set to nonzero
   if it represents a frameless function invocation.  */

/* 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)
     FRAME frame;
{
  CORE_ADDR func_start, after_prologue;
  func_start = (get_pc_function_start (frame->pc) +
		FUNCTION_START_OFFSET);
  if (func_start)
    {
      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.  */
      SKIP_PROLOGUE_FRAMELESS_P (after_prologue);
#else
      SKIP_PROLOGUE (after_prologue);
#endif
      return after_prologue == func_start;
    }
  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_info (next_frame)
     FRAME next_frame;
{
  FRAME_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 (!current_frame)
	{
	  error ("You haven't set up a process's stack to examine.");
	}

      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.  */
#ifdef FRAMELESS_FUNCTION_INVOCATION
  /* 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))
    {
      FRAMELESS_FUNCTION_INVOCATION (next_frame, fromleaf);
      if (fromleaf)
	address = next_frame->frame;
    }
#endif

  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));

  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.

   To answer the question, yes the sparc needs INIT_FRAME_PC after
   INIT_EXTRA_FRAME_INFO.  Suggested 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.
   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.  */

#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 it's value
     (see tm-sparc.h).  We want the pc saved in the inferior frame. */
  INIT_FRAME_PC(fromleaf, prev);

  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)
     FRAME frame;
{
  struct frame_info *fi;
  fi = get_frame_info (frame);
  return fi->pc;
}

#if defined (FRAME_FIND_SAVED_REGS)
/* Find the addresses in which registers are saved in FRAME.  */

void
get_frame_saved_regs (frame_info_addr, saved_regs_addr)
     struct frame_info *frame_info_addr;
     struct frame_saved_regs *saved_regs_addr;
{
  FRAME_FIND_SAVED_REGS (frame_info_addr, *saved_regs_addr);
}
#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)
     FRAME frame;
{
  struct frame_info *fi;
  CORE_ADDR pc;

  fi = get_frame_info (frame);

  pc = fi->pc;
  if (fi->next != 0 && fi->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 fi->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)
     FRAME 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, 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 (pc, pindex)
     register CORE_ADDR pc;
     int *pindex;
{
  register struct block *b;
  register int bot, top, half;
  register struct symtab *s;
  struct blockvector *bl;

  /* First search all symtabs for one whose file contains our pc */
  s = find_pc_symtab (pc);
  if (s == 0)
    return 0;

  bl = BLOCKVECTOR (s);
  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 innermost lexical block containing the specified pc value,
   or 0 if there is none.  */

struct block *
block_for_pc (pc)
     register CORE_ADDR pc;
{
  register struct blockvector *bl;
  int index;

  bl = blockvector_for_pc (pc, &index);
  if (bl)
    return BLOCKVECTOR_BLOCK (bl, index);
  return 0;
}

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

struct symbol *
find_pc_function (pc)
     CORE_ADDR pc;
{
  register struct block *b = block_for_pc (pc);
  if (b == 0)
    return 0;
  return block_function (b);
}

/* 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;

/* 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;
}

/* Finds the "function" (text symbol) that is smaller than PC but
   greatest of all of the potential text symbols.  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_partial_function (pc, name, address, endaddr)
     CORE_ADDR pc;
     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 *sec;

  if (pc >= cache_pc_function_low && pc < cache_pc_function_high)
    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 (pc, (char *)NULL))
    {
      cache_pc_function_low = SIGTRAMP_START;
      cache_pc_function_high = SIGTRAMP_END;
      cache_pc_function_name = "<sigtramp>";

      goto return_cached_value;
    }
#endif

  msymbol = lookup_minimal_symbol_by_pc (pc);
  pst = find_pc_psymtab (pc);
  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_function (pc);
	  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);
	      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_psymbol (pst, pc);

	  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.  */

  sec = find_pc_section (pc);

  if (!sec)
    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;
    }

  /* See if we're in a transfer table for Sun shared libs.  */

  if (msymbol -> type == mst_text)
    cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
  else
    /* It is a transfer table for Sun shared libraries.  */
    cache_pc_function_low = pc - FUNCTION_START_OFFSET;

  cache_pc_function_name = SYMBOL_NAME (msymbol);

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

  if (SYMBOL_NAME (msymbol + 1) != NULL
      && SYMBOL_VALUE_ADDRESS (msymbol + 1) < sec->endaddr)
    cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + 1);
  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 = sec->endaddr;

 return_cached_value:
  if (address)
    *address = cache_pc_function_low;
  if (name)
    *name = cache_pc_function_name;
  if (endaddr)
    *endaddr = cache_pc_function_high;
  return 1;
}

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

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

  if (block == NULL)
    return NULL;

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

  frame = 0;
  while (1)
    {
      frame = get_prev_frame (frame);
      if (frame == 0)
	return 0;
      fi = get_frame_info (frame);
      if (fi->pc >= start && fi->pc < end)
	return frame;
    }
}

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

CORE_ADDR
sigtramp_saved_pc (frame)
     FRAME 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 */

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