aboutsummaryrefslogtreecommitdiff
path: root/gdb/blockframe.c
blob: eb032258939d54e3d6e536926e31adde0dccf569 (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
/* Get info from stack frames; convert between frames, blocks,
   functions and pc values.

   Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
   1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
   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 "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"
#include "regcache.h"
#include "gdb_assert.h"
#include "dummy-frame.h"
#include "command.h"
#include "gdbcmd.h"
#include "block.h"

/* Prototypes for exported functions. */

void _initialize_blockframe (void);

/* Test whether PC is in the range of addresses that corresponds to
   the "main" function.  */

int
inside_main_func (CORE_ADDR pc)
{
  struct minimal_symbol *msymbol;

  if (symfile_objfile == 0)
    return 0;

  msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);

  /* If the address range hasn't been set up at symbol reading time,
     set it up now.  */

  if (msymbol != NULL
      && symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC
      && symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
    {
      /* brobecker/2003-10-10: We used to rely on lookup_symbol() to
	 search the symbol associated to the "main" function.
	 Unfortunately, lookup_symbol() uses the current-language
	 la_lookup_symbol_nonlocal function to do the global symbol
	 search.  Depending on the language, this can introduce
	 certain side-effects, because certain languages, for instance
	 Ada, may find more than one match.  Therefore we prefer to
	 search the "main" function symbol using its address rather
	 than its name.  */
      struct symbol *mainsym =
	find_pc_function (SYMBOL_VALUE_ADDRESS (msymbol));

      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));
	}
    }

  /* Not in the normal symbol tables, see if "main" is in the partial
     symbol table.  If it's not, then give up.  */
  if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_text)
    {
      CORE_ADDR maddr = SYMBOL_VALUE_ADDRESS (msymbol);
      asection *msect = SYMBOL_BFD_SECTION (msymbol);
      struct obj_section *osect = find_pc_sect_section (maddr, msect);

      if (osect != NULL)
	{
	  int i;

	  /* 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_LINKAGE_NAME (msymbol + i) != NULL; i++)
	    {
	      if (SYMBOL_VALUE_ADDRESS (msymbol + i) != maddr
		  && SYMBOL_BFD_SECTION (msymbol + i) == msect)
		break;
	    }

	  symfile_objfile->ei.main_func_lowpc = maddr;

	  /* Use the lesser of the next minimal symbol in the same
	     section, or the end of the section, as the end of the
	     function.  */
	  if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
	      && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
	    symfile_objfile->ei.main_func_highpc =
	      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.  */
	    symfile_objfile->ei.main_func_highpc = osect->endaddr;
	}
    }

  return (symfile_objfile->ei.main_func_lowpc <= pc
	  && symfile_objfile->ei.main_func_highpc > pc);
}

/* Test whether THIS_FRAME is inside the process entry point function.  */

int
inside_entry_func (struct frame_info *this_frame)
{
  return (get_frame_func (this_frame) == entry_point_address ());
}

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

int
legacy_frameless_look_for_prologue (struct frame_info *frame)
{
  CORE_ADDR func_start;

  func_start = get_frame_func (frame);
  if (func_start)
    {
      func_start += DEPRECATED_FUNCTION_START_OFFSET;
      /* NOTE: cagney/2004-02-09: Eliminated per-architecture
         PROLOGUE_FRAMELESS_P call as architectures with custom
         implementations had all been deleted.  Eventually even this
         function can go - GDB no longer tries to differentiate
         between framed, frameless and stackless functions.  They are
         all now considered equally evil :-^.  */
      /* If skipping the prologue ends up skips nothing, there must be
         no prologue and hence no code creating a frame.  There for
         the function is "frameless" :-/.  */
      return func_start == SKIP_PROLOGUE (func_start);
    }
  else if (get_frame_pc (frame) == 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;
}

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

   If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
   address we used to choose the block.  We use this to find a source
   line, to decide which macro definitions are in scope.

   The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
   PC, and may not really be a valid PC at all.  For example, in the
   caller of a function declared to never return, the code at the
   return address will never be reached, so the call instruction may
   be the very last instruction in the block.  So the address we use
   to choose the block is actually one byte before the return address
   --- hopefully pointing us at the call instruction, or its delay
   slot instruction.  */

struct block *
get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
{
  const CORE_ADDR pc = get_frame_address_in_block (frame);

  if (addr_in_block)
    *addr_in_block = pc;

  return block_for_pc (pc);
}

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

  bl = block_for_pc (pc);
  if (bl)
    {
      struct symbol *symbol = block_function (bl);

      if (symbol)
	{
	  bl = SYMBOL_BLOCK_VALUE (symbol);
	  return BLOCK_START (bl);
	}
    }

  msymbol = lookup_minimal_symbol_by_pc (pc);
  if (msymbol)
    {
      CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);

      if (find_pc_section (fstart))
	return fstart;
    }

  return 0;
}

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

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

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

struct symbol *
find_pc_sect_function (CORE_ADDR pc, struct bfd_section *section)
{
  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 (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 bfd_section *cache_pc_function_section = NULL;

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

void
clear_pc_function_cache (void)
{
  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.  */

/* Backward compatibility, no section argument.  */

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

  /* To ensure that the symbol returned belongs to the correct setion
     (and that the last [random] symbol from the previous section
     isn't returned) try to find the section containing PC.  First try
     the overlay code (which by default returns NULL); and second try
     the normal section code (which almost always succeeds).  */
  section = find_pc_overlay (pc);
  if (section == NULL)
    {
      struct obj_section *obj_section = find_pc_section (pc);
      if (obj_section == NULL)
	section = NULL;
      else
	section = obj_section->the_bfd_section;
    }

  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;

  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 = DEPRECATED_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 = DEPRECATED_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 = DEPRECATED_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; DEPRECATED_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 (DEPRECATED_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;
}

/* 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 (struct block *block)
{
  struct frame_info *frame;
  CORE_ADDR start;
  CORE_ADDR end;
  CORE_ADDR calling_pc;

  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;
      calling_pc = get_frame_address_in_block (frame);
      if (calling_pc >= start && calling_pc < end)
	return frame;
    }
}

/* 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.  */

/* 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
legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
{
  /* Don't prune CALL_DUMMY frames.  */
  if (deprecated_pc_in_call_dummy (get_frame_pc (fi)))
    return 1;

  /* If the new frame pointer is zero, then it isn't valid.  */
  if (fp == 0)
    return 0;
  
  /* If the new frame would be inside (younger than) the previous frame,
     then it isn't valid.  */
  if (INNER_THAN (fp, get_frame_base (fi)))
    return 0;
  
  /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
     call it now.  */
  if (DEPRECATED_FRAME_CHAIN_VALID_P ())
    return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);

  /* If we're already inside the entry function for the main objfile,
     then it isn't valid.  */
  if (inside_entry_func (fi))
    return 0;

  return 1;
}