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[/] [or1k/] [trunk/] [gdb-5.3/] [gdb/] [minsyms.c] - Blame information for rev 1765

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1 1181 sfurman
/* GDB routines for manipulating the minimal symbol tables.
2
   Copyright 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
3
   Free Software Foundation, Inc.
4
   Contributed by Cygnus Support, using pieces from other GDB modules.
5
 
6
   This file is part of GDB.
7
 
8
   This program is free software; you can redistribute it and/or modify
9
   it under the terms of the GNU General Public License as published by
10
   the Free Software Foundation; either version 2 of the License, or
11
   (at your option) any later version.
12
 
13
   This program is distributed in the hope that it will be useful,
14
   but WITHOUT ANY WARRANTY; without even the implied warranty of
15
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16
   GNU General Public License for more details.
17
 
18
   You should have received a copy of the GNU General Public License
19
   along with this program; if not, write to the Free Software
20
   Foundation, Inc., 59 Temple Place - Suite 330,
21
   Boston, MA 02111-1307, USA.  */
22
 
23
 
24
/* This file contains support routines for creating, manipulating, and
25
   destroying minimal symbol tables.
26
 
27
   Minimal symbol tables are used to hold some very basic information about
28
   all defined global symbols (text, data, bss, abs, etc).  The only two
29
   required pieces of information are the symbol's name and the address
30
   associated with that symbol.
31
 
32
   In many cases, even if a file was compiled with no special options for
33
   debugging at all, as long as was not stripped it will contain sufficient
34
   information to build useful minimal symbol tables using this structure.
35
 
36
   Even when a file contains enough debugging information to build a full
37
   symbol table, these minimal symbols are still useful for quickly mapping
38
   between names and addresses, and vice versa.  They are also sometimes used
39
   to figure out what full symbol table entries need to be read in. */
40
 
41
 
42
#include "defs.h"
43
#include <ctype.h>
44
#include "gdb_string.h"
45
#include "symtab.h"
46
#include "bfd.h"
47
#include "symfile.h"
48
#include "objfiles.h"
49
#include "demangle.h"
50
#include "value.h"
51
#include "cp-abi.h"
52
 
53
/* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
54
   At the end, copy them all into one newly allocated location on an objfile's
55
   symbol obstack.  */
56
 
57
#define BUNCH_SIZE 127
58
 
59
struct msym_bunch
60
  {
61
    struct msym_bunch *next;
62
    struct minimal_symbol contents[BUNCH_SIZE];
63
  };
64
 
65
/* Bunch currently being filled up.
66
   The next field points to chain of filled bunches.  */
67
 
68
static struct msym_bunch *msym_bunch;
69
 
70
/* Number of slots filled in current bunch.  */
71
 
72
static int msym_bunch_index;
73
 
74
/* Total number of minimal symbols recorded so far for the objfile.  */
75
 
76
static int msym_count;
77
 
78
/* Compute a hash code based using the same criteria as `strcmp_iw'.  */
79
 
80
unsigned int
81
msymbol_hash_iw (const char *string)
82
{
83
  unsigned int hash = 0;
84
  while (*string && *string != '(')
85
    {
86
      while (isspace (*string))
87
        ++string;
88
      if (*string && *string != '(')
89
        {
90
          hash = hash * 67 + *string - 113;
91
          ++string;
92
        }
93
    }
94
  return hash;
95
}
96
 
97
/* Compute a hash code for a string.  */
98
 
99
unsigned int
100
msymbol_hash (const char *string)
101
{
102
  unsigned int hash = 0;
103
  for (; *string; ++string)
104
    hash = hash * 67 + *string - 113;
105
  return hash;
106
}
107
 
108
/* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE.  */
109
void
110
add_minsym_to_hash_table (struct minimal_symbol *sym,
111
                          struct minimal_symbol **table)
112
{
113
  if (sym->hash_next == NULL)
114
    {
115
      unsigned int hash = msymbol_hash (SYMBOL_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
116
      sym->hash_next = table[hash];
117
      table[hash] = sym;
118
    }
119
}
120
 
121
/* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
122
   TABLE.  */
123
static void
124
add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
125
                                  struct minimal_symbol **table)
126
{
127
  if (sym->demangled_hash_next == NULL)
128
    {
129
      unsigned int hash = msymbol_hash_iw (SYMBOL_DEMANGLED_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
130
      sym->demangled_hash_next = table[hash];
131
      table[hash] = sym;
132
    }
133
}
134
 
135
 
136
/* Look through all the current minimal symbol tables and find the
137
   first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
138
   the search to that objfile.  If SFILE is non-NULL, limit the search
139
   to that source file.  Returns a pointer to the minimal symbol that
140
   matches, or NULL if no match is found.
141
 
142
   Note:  One instance where there may be duplicate minimal symbols with
143
   the same name is when the symbol tables for a shared library and the
144
   symbol tables for an executable contain global symbols with the same
145
   names (the dynamic linker deals with the duplication). */
146
 
147
struct minimal_symbol *
148
lookup_minimal_symbol (register const char *name, const char *sfile,
149
                       struct objfile *objf)
150
{
151
  struct objfile *objfile;
152
  struct minimal_symbol *msymbol;
153
  struct minimal_symbol *found_symbol = NULL;
154
  struct minimal_symbol *found_file_symbol = NULL;
155
  struct minimal_symbol *trampoline_symbol = NULL;
156
 
157
  unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
158
  unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
159
 
160
#ifdef SOFUN_ADDRESS_MAYBE_MISSING
161
  if (sfile != NULL)
162
    {
163
      char *p = strrchr (sfile, '/');
164
      if (p != NULL)
165
        sfile = p + 1;
166
    }
167
#endif
168
 
169
  for (objfile = object_files;
170
       objfile != NULL && found_symbol == NULL;
171
       objfile = objfile->next)
172
    {
173
      if (objf == NULL || objf == objfile)
174
        {
175
          /* Do two passes: the first over the ordinary hash table,
176
             and the second over the demangled hash table.  */
177
        int pass;
178
 
179
        for (pass = 1; pass <= 2 && found_symbol == NULL; pass++)
180
            {
181
            /* Select hash list according to pass.  */
182
            if (pass == 1)
183
              msymbol = objfile->msymbol_hash[hash];
184
            else
185
              msymbol = objfile->msymbol_demangled_hash[dem_hash];
186
 
187
            while (msymbol != NULL && found_symbol == NULL)
188
                {
189
                if (SYMBOL_MATCHES_NAME (msymbol, name))
190
                    {
191
                    switch (MSYMBOL_TYPE (msymbol))
192
                      {
193
                      case mst_file_text:
194
                      case mst_file_data:
195
                      case mst_file_bss:
196
#ifdef SOFUN_ADDRESS_MAYBE_MISSING
197
                        if (sfile == NULL || STREQ (msymbol->filename, sfile))
198
                          found_file_symbol = msymbol;
199
#else
200
                        /* We have neither the ability nor the need to
201
                           deal with the SFILE parameter.  If we find
202
                           more than one symbol, just return the latest
203
                           one (the user can't expect useful behavior in
204
                           that case).  */
205
                        found_file_symbol = msymbol;
206
#endif
207
                        break;
208
 
209
                      case mst_solib_trampoline:
210
 
211
                        /* If a trampoline symbol is found, we prefer to
212
                           keep looking for the *real* symbol. If the
213
                           actual symbol is not found, then we'll use the
214
                           trampoline entry. */
215
                        if (trampoline_symbol == NULL)
216
                          trampoline_symbol = msymbol;
217
                        break;
218
 
219
                      case mst_unknown:
220
                      default:
221
                        found_symbol = msymbol;
222
                        break;
223
                      }
224
                    }
225
 
226
                /* Find the next symbol on the hash chain.  */
227
                if (pass == 1)
228
                  msymbol = msymbol->hash_next;
229
                else
230
                  msymbol = msymbol->demangled_hash_next;
231
                }
232
            }
233
        }
234
    }
235
  /* External symbols are best.  */
236
  if (found_symbol)
237
    return found_symbol;
238
 
239
  /* File-local symbols are next best.  */
240
  if (found_file_symbol)
241
    return found_file_symbol;
242
 
243
  /* Symbols for shared library trampolines are next best.  */
244
  if (trampoline_symbol)
245
    return trampoline_symbol;
246
 
247
  return NULL;
248
}
249
 
250
/* Look through all the current minimal symbol tables and find the
251
   first minimal symbol that matches NAME and of text type.
252
   If OBJF is non-NULL, limit
253
   the search to that objfile.  If SFILE is non-NULL, limit the search
254
   to that source file.  Returns a pointer to the minimal symbol that
255
   matches, or NULL if no match is found.
256
 */
257
 
258
struct minimal_symbol *
259
lookup_minimal_symbol_text (register const char *name, const char *sfile,
260
                            struct objfile *objf)
261
{
262
  struct objfile *objfile;
263
  struct minimal_symbol *msymbol;
264
  struct minimal_symbol *found_symbol = NULL;
265
  struct minimal_symbol *found_file_symbol = NULL;
266
 
267
#ifdef SOFUN_ADDRESS_MAYBE_MISSING
268
  if (sfile != NULL)
269
    {
270
      char *p = strrchr (sfile, '/');
271
      if (p != NULL)
272
        sfile = p + 1;
273
    }
274
#endif
275
 
276
  for (objfile = object_files;
277
       objfile != NULL && found_symbol == NULL;
278
       objfile = objfile->next)
279
    {
280
      if (objf == NULL || objf == objfile)
281
        {
282
          for (msymbol = objfile->msymbols;
283
               msymbol != NULL && SYMBOL_NAME (msymbol) != NULL &&
284
               found_symbol == NULL;
285
               msymbol++)
286
            {
287
              if (SYMBOL_MATCHES_NAME (msymbol, name) &&
288
                  (MSYMBOL_TYPE (msymbol) == mst_text ||
289
                   MSYMBOL_TYPE (msymbol) == mst_file_text))
290
                {
291
                  switch (MSYMBOL_TYPE (msymbol))
292
                    {
293
                    case mst_file_text:
294
#ifdef SOFUN_ADDRESS_MAYBE_MISSING
295
                      if (sfile == NULL || STREQ (msymbol->filename, sfile))
296
                        found_file_symbol = msymbol;
297
#else
298
                      /* We have neither the ability nor the need to
299
                         deal with the SFILE parameter.  If we find
300
                         more than one symbol, just return the latest
301
                         one (the user can't expect useful behavior in
302
                         that case).  */
303
                      found_file_symbol = msymbol;
304
#endif
305
                      break;
306
                    default:
307
                      found_symbol = msymbol;
308
                      break;
309
                    }
310
                }
311
            }
312
        }
313
    }
314
  /* External symbols are best.  */
315
  if (found_symbol)
316
    return found_symbol;
317
 
318
  /* File-local symbols are next best.  */
319
  if (found_file_symbol)
320
    return found_file_symbol;
321
 
322
  return NULL;
323
}
324
 
325
/* Look through all the current minimal symbol tables and find the
326
   first minimal symbol that matches NAME and of solib trampoline type.
327
   If OBJF is non-NULL, limit
328
   the search to that objfile.  If SFILE is non-NULL, limit the search
329
   to that source file.  Returns a pointer to the minimal symbol that
330
   matches, or NULL if no match is found.
331
 */
332
 
333
struct minimal_symbol *
334
lookup_minimal_symbol_solib_trampoline (register const char *name,
335
                                        const char *sfile, struct objfile *objf)
336
{
337
  struct objfile *objfile;
338
  struct minimal_symbol *msymbol;
339
  struct minimal_symbol *found_symbol = NULL;
340
 
341
#ifdef SOFUN_ADDRESS_MAYBE_MISSING
342
  if (sfile != NULL)
343
    {
344
      char *p = strrchr (sfile, '/');
345
      if (p != NULL)
346
        sfile = p + 1;
347
    }
348
#endif
349
 
350
  for (objfile = object_files;
351
       objfile != NULL && found_symbol == NULL;
352
       objfile = objfile->next)
353
    {
354
      if (objf == NULL || objf == objfile)
355
        {
356
          for (msymbol = objfile->msymbols;
357
               msymbol != NULL && SYMBOL_NAME (msymbol) != NULL &&
358
               found_symbol == NULL;
359
               msymbol++)
360
            {
361
              if (SYMBOL_MATCHES_NAME (msymbol, name) &&
362
                  MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
363
                return msymbol;
364
            }
365
        }
366
    }
367
 
368
  return NULL;
369
}
370
 
371
 
372
/* Search through the minimal symbol table for each objfile and find
373
   the symbol whose address is the largest address that is still less
374
   than or equal to PC, and matches SECTION (if non-null).  Returns a
375
   pointer to the minimal symbol if such a symbol is found, or NULL if
376
   PC is not in a suitable range.  Note that we need to look through
377
   ALL the minimal symbol tables before deciding on the symbol that
378
   comes closest to the specified PC.  This is because objfiles can
379
   overlap, for example objfile A has .text at 0x100 and .data at
380
   0x40000 and objfile B has .text at 0x234 and .data at 0x40048.  */
381
 
382
struct minimal_symbol *
383
lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, asection *section)
384
{
385
  int lo;
386
  int hi;
387
  int new;
388
  struct objfile *objfile;
389
  struct minimal_symbol *msymbol;
390
  struct minimal_symbol *best_symbol = NULL;
391
 
392
  /* pc has to be in a known section. This ensures that anything beyond
393
     the end of the last segment doesn't appear to be part of the last
394
     function in the last segment.  */
395
  if (find_pc_section (pc) == NULL)
396
    return NULL;
397
 
398
  for (objfile = object_files;
399
       objfile != NULL;
400
       objfile = objfile->next)
401
    {
402
      /* If this objfile has a minimal symbol table, go search it using
403
         a binary search.  Note that a minimal symbol table always consists
404
         of at least two symbols, a "real" symbol and the terminating
405
         "null symbol".  If there are no real symbols, then there is no
406
         minimal symbol table at all. */
407
 
408
      if ((msymbol = objfile->msymbols) != NULL)
409
        {
410
          lo = 0;
411
          hi = objfile->minimal_symbol_count - 1;
412
 
413
          /* This code assumes that the minimal symbols are sorted by
414
             ascending address values.  If the pc value is greater than or
415
             equal to the first symbol's address, then some symbol in this
416
             minimal symbol table is a suitable candidate for being the
417
             "best" symbol.  This includes the last real symbol, for cases
418
             where the pc value is larger than any address in this vector.
419
 
420
             By iterating until the address associated with the current
421
             hi index (the endpoint of the test interval) is less than
422
             or equal to the desired pc value, we accomplish two things:
423
             (1) the case where the pc value is larger than any minimal
424
             symbol address is trivially solved, (2) the address associated
425
             with the hi index is always the one we want when the interation
426
             terminates.  In essence, we are iterating the test interval
427
             down until the pc value is pushed out of it from the high end.
428
 
429
             Warning: this code is trickier than it would appear at first. */
430
 
431
          /* Should also require that pc is <= end of objfile.  FIXME! */
432
          if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
433
            {
434
              while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
435
                {
436
                  /* pc is still strictly less than highest address */
437
                  /* Note "new" will always be >= lo */
438
                  new = (lo + hi) / 2;
439
                  if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
440
                      (lo == new))
441
                    {
442
                      hi = new;
443
                    }
444
                  else
445
                    {
446
                      lo = new;
447
                    }
448
                }
449
 
450
              /* If we have multiple symbols at the same address, we want
451
                 hi to point to the last one.  That way we can find the
452
                 right symbol if it has an index greater than hi.  */
453
              while (hi < objfile->minimal_symbol_count - 1
454
                     && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
455
                         == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
456
                hi++;
457
 
458
              /* The minimal symbol indexed by hi now is the best one in this
459
                 objfile's minimal symbol table.  See if it is the best one
460
                 overall. */
461
 
462
              /* Skip any absolute symbols.  This is apparently what adb
463
                 and dbx do, and is needed for the CM-5.  There are two
464
                 known possible problems: (1) on ELF, apparently end, edata,
465
                 etc. are absolute.  Not sure ignoring them here is a big
466
                 deal, but if we want to use them, the fix would go in
467
                 elfread.c.  (2) I think shared library entry points on the
468
                 NeXT are absolute.  If we want special handling for this
469
                 it probably should be triggered by a special
470
                 mst_abs_or_lib or some such.  */
471
              while (hi >= 0
472
                     && msymbol[hi].type == mst_abs)
473
                --hi;
474
 
475
              /* If "section" specified, skip any symbol from wrong section */
476
              /* This is the new code that distinguishes it from the old function */
477
              if (section)
478
                while (hi >= 0
479
                       /* Some types of debug info, such as COFF,
480
                          don't fill the bfd_section member, so don't
481
                          throw away symbols on those platforms.  */
482
                       && SYMBOL_BFD_SECTION (&msymbol[hi]) != NULL
483
                       && SYMBOL_BFD_SECTION (&msymbol[hi]) != section)
484
                  --hi;
485
 
486
              if (hi >= 0
487
                  && ((best_symbol == NULL) ||
488
                      (SYMBOL_VALUE_ADDRESS (best_symbol) <
489
                       SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
490
                {
491
                  best_symbol = &msymbol[hi];
492
                }
493
            }
494
        }
495
    }
496
  return (best_symbol);
497
}
498
 
499
/* Backward compatibility: search through the minimal symbol table
500
   for a matching PC (no section given) */
501
 
502
struct minimal_symbol *
503
lookup_minimal_symbol_by_pc (CORE_ADDR pc)
504
{
505
  return lookup_minimal_symbol_by_pc_section (pc, find_pc_mapped_section (pc));
506
}
507
 
508
 
509
/* Return leading symbol character for a BFD. If BFD is NULL,
510
   return the leading symbol character from the main objfile.  */
511
 
512
static int get_symbol_leading_char (bfd *);
513
 
514
static int
515
get_symbol_leading_char (bfd *abfd)
516
{
517
  if (abfd != NULL)
518
    return bfd_get_symbol_leading_char (abfd);
519
  if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
520
    return bfd_get_symbol_leading_char (symfile_objfile->obfd);
521
  return 0;
522
}
523
 
524
/* Prepare to start collecting minimal symbols.  Note that presetting
525
   msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
526
   symbol to allocate the memory for the first bunch. */
527
 
528
void
529
init_minimal_symbol_collection (void)
530
{
531
  msym_count = 0;
532
  msym_bunch = NULL;
533
  msym_bunch_index = BUNCH_SIZE;
534
}
535
 
536
void
537
prim_record_minimal_symbol (const char *name, CORE_ADDR address,
538
                            enum minimal_symbol_type ms_type,
539
                            struct objfile *objfile)
540
{
541
  int section;
542
 
543
  switch (ms_type)
544
    {
545
    case mst_text:
546
    case mst_file_text:
547
    case mst_solib_trampoline:
548
      section = SECT_OFF_TEXT (objfile);
549
      break;
550
    case mst_data:
551
    case mst_file_data:
552
      section = SECT_OFF_DATA (objfile);
553
      break;
554
    case mst_bss:
555
    case mst_file_bss:
556
      section = SECT_OFF_BSS (objfile);
557
      break;
558
    default:
559
      section = -1;
560
    }
561
 
562
  prim_record_minimal_symbol_and_info (name, address, ms_type,
563
                                       NULL, section, NULL, objfile);
564
}
565
 
566
/* Record a minimal symbol in the msym bunches.  Returns the symbol
567
   newly created.  */
568
 
569
struct minimal_symbol *
570
prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
571
                                     enum minimal_symbol_type ms_type,
572
                                     char *info, int section,
573
                                     asection *bfd_section,
574
                                     struct objfile *objfile)
575
{
576
  register struct msym_bunch *new;
577
  register struct minimal_symbol *msymbol;
578
 
579
  if (ms_type == mst_file_text)
580
    {
581
      /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
582
         the minimal symbols, because if there is also another symbol
583
         at the same address (e.g. the first function of the file),
584
         lookup_minimal_symbol_by_pc would have no way of getting the
585
         right one.  */
586
      if (name[0] == 'g'
587
          && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
588
              || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
589
        return (NULL);
590
 
591
      {
592
        const char *tempstring = name;
593
        if (tempstring[0] == get_symbol_leading_char (objfile->obfd))
594
          ++tempstring;
595
        if (STREQN (tempstring, "__gnu_compiled", 14))
596
          return (NULL);
597
      }
598
    }
599
 
600
  if (msym_bunch_index == BUNCH_SIZE)
601
    {
602
      new = (struct msym_bunch *) xmalloc (sizeof (struct msym_bunch));
603
      msym_bunch_index = 0;
604
      new->next = msym_bunch;
605
      msym_bunch = new;
606
    }
607
  msymbol = &msym_bunch->contents[msym_bunch_index];
608
  SYMBOL_NAME (msymbol) = obsavestring ((char *) name, strlen (name),
609
                                        &objfile->symbol_obstack);
610
  SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown);
611
  SYMBOL_VALUE_ADDRESS (msymbol) = address;
612
  SYMBOL_SECTION (msymbol) = section;
613
  SYMBOL_BFD_SECTION (msymbol) = bfd_section;
614
 
615
  MSYMBOL_TYPE (msymbol) = ms_type;
616
  /* FIXME:  This info, if it remains, needs its own field.  */
617
  MSYMBOL_INFO (msymbol) = info;        /* FIXME! */
618
 
619
  /* The hash pointers must be cleared! If they're not,
620
     add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
621
  msymbol->hash_next = NULL;
622
  msymbol->demangled_hash_next = NULL;
623
 
624
  msym_bunch_index++;
625
  msym_count++;
626
  OBJSTAT (objfile, n_minsyms++);
627
  return msymbol;
628
}
629
 
630
/* Compare two minimal symbols by address and return a signed result based
631
   on unsigned comparisons, so that we sort into unsigned numeric order.
632
   Within groups with the same address, sort by name.  */
633
 
634
static int
635
compare_minimal_symbols (const void *fn1p, const void *fn2p)
636
{
637
  register const struct minimal_symbol *fn1;
638
  register const struct minimal_symbol *fn2;
639
 
640
  fn1 = (const struct minimal_symbol *) fn1p;
641
  fn2 = (const struct minimal_symbol *) fn2p;
642
 
643
  if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
644
    {
645
      return (-1);              /* addr 1 is less than addr 2 */
646
    }
647
  else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
648
    {
649
      return (1);               /* addr 1 is greater than addr 2 */
650
    }
651
  else
652
    /* addrs are equal: sort by name */
653
    {
654
      char *name1 = SYMBOL_NAME (fn1);
655
      char *name2 = SYMBOL_NAME (fn2);
656
 
657
      if (name1 && name2)       /* both have names */
658
        return strcmp (name1, name2);
659
      else if (name2)
660
        return 1;               /* fn1 has no name, so it is "less" */
661
      else if (name1)           /* fn2 has no name, so it is "less" */
662
        return -1;
663
      else
664
        return (0);              /* neither has a name, so they're equal. */
665
    }
666
}
667
 
668
/* Discard the currently collected minimal symbols, if any.  If we wish
669
   to save them for later use, we must have already copied them somewhere
670
   else before calling this function.
671
 
672
   FIXME:  We could allocate the minimal symbol bunches on their own
673
   obstack and then simply blow the obstack away when we are done with
674
   it.  Is it worth the extra trouble though? */
675
 
676
static void
677
do_discard_minimal_symbols_cleanup (void *arg)
678
{
679
  register struct msym_bunch *next;
680
 
681
  while (msym_bunch != NULL)
682
    {
683
      next = msym_bunch->next;
684
      xfree (msym_bunch);
685
      msym_bunch = next;
686
    }
687
}
688
 
689
struct cleanup *
690
make_cleanup_discard_minimal_symbols (void)
691
{
692
  return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
693
}
694
 
695
 
696
 
697
/* Compact duplicate entries out of a minimal symbol table by walking
698
   through the table and compacting out entries with duplicate addresses
699
   and matching names.  Return the number of entries remaining.
700
 
701
   On entry, the table resides between msymbol[0] and msymbol[mcount].
702
   On exit, it resides between msymbol[0] and msymbol[result_count].
703
 
704
   When files contain multiple sources of symbol information, it is
705
   possible for the minimal symbol table to contain many duplicate entries.
706
   As an example, SVR4 systems use ELF formatted object files, which
707
   usually contain at least two different types of symbol tables (a
708
   standard ELF one and a smaller dynamic linking table), as well as
709
   DWARF debugging information for files compiled with -g.
710
 
711
   Without compacting, the minimal symbol table for gdb itself contains
712
   over a 1000 duplicates, about a third of the total table size.  Aside
713
   from the potential trap of not noticing that two successive entries
714
   identify the same location, this duplication impacts the time required
715
   to linearly scan the table, which is done in a number of places.  So we
716
   just do one linear scan here and toss out the duplicates.
717
 
718
   Note that we are not concerned here about recovering the space that
719
   is potentially freed up, because the strings themselves are allocated
720
   on the symbol_obstack, and will get automatically freed when the symbol
721
   table is freed.  The caller can free up the unused minimal symbols at
722
   the end of the compacted region if their allocation strategy allows it.
723
 
724
   Also note we only go up to the next to last entry within the loop
725
   and then copy the last entry explicitly after the loop terminates.
726
 
727
   Since the different sources of information for each symbol may
728
   have different levels of "completeness", we may have duplicates
729
   that have one entry with type "mst_unknown" and the other with a
730
   known type.  So if the one we are leaving alone has type mst_unknown,
731
   overwrite its type with the type from the one we are compacting out.  */
732
 
733
static int
734
compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
735
                         struct objfile *objfile)
736
{
737
  struct minimal_symbol *copyfrom;
738
  struct minimal_symbol *copyto;
739
 
740
  if (mcount > 0)
741
    {
742
      copyfrom = copyto = msymbol;
743
      while (copyfrom < msymbol + mcount - 1)
744
        {
745
          if (SYMBOL_VALUE_ADDRESS (copyfrom) ==
746
              SYMBOL_VALUE_ADDRESS ((copyfrom + 1)) &&
747
              (STREQ (SYMBOL_NAME (copyfrom), SYMBOL_NAME ((copyfrom + 1)))))
748
            {
749
              if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
750
                {
751
                  MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
752
                }
753
              copyfrom++;
754
            }
755
          else
756
            *copyto++ = *copyfrom++;
757
        }
758
      *copyto++ = *copyfrom++;
759
      mcount = copyto - msymbol;
760
    }
761
  return (mcount);
762
}
763
 
764
/* Build (or rebuild) the minimal symbol hash tables.  This is necessary
765
   after compacting or sorting the table since the entries move around
766
   thus causing the internal minimal_symbol pointers to become jumbled. */
767
 
768
static void
769
build_minimal_symbol_hash_tables (struct objfile *objfile)
770
{
771
  int i;
772
  struct minimal_symbol *msym;
773
 
774
  /* Clear the hash tables. */
775
  for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
776
    {
777
      objfile->msymbol_hash[i] = 0;
778
      objfile->msymbol_demangled_hash[i] = 0;
779
    }
780
 
781
  /* Now, (re)insert the actual entries. */
782
  for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
783
       i > 0;
784
       i--, msym++)
785
    {
786
      msym->hash_next = 0;
787
      add_minsym_to_hash_table (msym, objfile->msymbol_hash);
788
 
789
      msym->demangled_hash_next = 0;
790
      if (SYMBOL_DEMANGLED_NAME (msym) != NULL)
791
        add_minsym_to_demangled_hash_table (msym,
792
                                            objfile->msymbol_demangled_hash);
793
    }
794
}
795
 
796
/* Add the minimal symbols in the existing bunches to the objfile's official
797
   minimal symbol table.  In most cases there is no minimal symbol table yet
798
   for this objfile, and the existing bunches are used to create one.  Once
799
   in a while (for shared libraries for example), we add symbols (e.g. common
800
   symbols) to an existing objfile.
801
 
802
   Because of the way minimal symbols are collected, we generally have no way
803
   of knowing what source language applies to any particular minimal symbol.
804
   Specifically, we have no way of knowing if the minimal symbol comes from a
805
   C++ compilation unit or not.  So for the sake of supporting cached
806
   demangled C++ names, we have no choice but to try and demangle each new one
807
   that comes in.  If the demangling succeeds, then we assume it is a C++
808
   symbol and set the symbol's language and demangled name fields
809
   appropriately.  Note that in order to avoid unnecessary demanglings, and
810
   allocating obstack space that subsequently can't be freed for the demangled
811
   names, we mark all newly added symbols with language_auto.  After
812
   compaction of the minimal symbols, we go back and scan the entire minimal
813
   symbol table looking for these new symbols.  For each new symbol we attempt
814
   to demangle it, and if successful, record it as a language_cplus symbol
815
   and cache the demangled form on the symbol obstack.  Symbols which don't
816
   demangle are marked as language_unknown symbols, which inhibits future
817
   attempts to demangle them if we later add more minimal symbols. */
818
 
819
void
820
install_minimal_symbols (struct objfile *objfile)
821
{
822
  register int bindex;
823
  register int mcount;
824
  register struct msym_bunch *bunch;
825
  register struct minimal_symbol *msymbols;
826
  int alloc_count;
827
  register char leading_char;
828
 
829
  if (msym_count > 0)
830
    {
831
      /* Allocate enough space in the obstack, into which we will gather the
832
         bunches of new and existing minimal symbols, sort them, and then
833
         compact out the duplicate entries.  Once we have a final table,
834
         we will give back the excess space.  */
835
 
836
      alloc_count = msym_count + objfile->minimal_symbol_count + 1;
837
      obstack_blank (&objfile->symbol_obstack,
838
                     alloc_count * sizeof (struct minimal_symbol));
839
      msymbols = (struct minimal_symbol *)
840
        obstack_base (&objfile->symbol_obstack);
841
 
842
      /* Copy in the existing minimal symbols, if there are any.  */
843
 
844
      if (objfile->minimal_symbol_count)
845
        memcpy ((char *) msymbols, (char *) objfile->msymbols,
846
            objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
847
 
848
      /* Walk through the list of minimal symbol bunches, adding each symbol
849
         to the new contiguous array of symbols.  Note that we start with the
850
         current, possibly partially filled bunch (thus we use the current
851
         msym_bunch_index for the first bunch we copy over), and thereafter
852
         each bunch is full. */
853
 
854
      mcount = objfile->minimal_symbol_count;
855
      leading_char = get_symbol_leading_char (objfile->obfd);
856
 
857
      for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
858
        {
859
          for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
860
            {
861
              msymbols[mcount] = bunch->contents[bindex];
862
              SYMBOL_LANGUAGE (&msymbols[mcount]) = language_auto;
863
              if (SYMBOL_NAME (&msymbols[mcount])[0] == leading_char)
864
                {
865
                  SYMBOL_NAME (&msymbols[mcount])++;
866
                }
867
            }
868
          msym_bunch_index = BUNCH_SIZE;
869
        }
870
 
871
      /* Sort the minimal symbols by address.  */
872
 
873
      qsort (msymbols, mcount, sizeof (struct minimal_symbol),
874
             compare_minimal_symbols);
875
 
876
      /* Compact out any duplicates, and free up whatever space we are
877
         no longer using.  */
878
 
879
      mcount = compact_minimal_symbols (msymbols, mcount, objfile);
880
 
881
      obstack_blank (&objfile->symbol_obstack,
882
               (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
883
      msymbols = (struct minimal_symbol *)
884
        obstack_finish (&objfile->symbol_obstack);
885
 
886
      /* We also terminate the minimal symbol table with a "null symbol",
887
         which is *not* included in the size of the table.  This makes it
888
         easier to find the end of the table when we are handed a pointer
889
         to some symbol in the middle of it.  Zero out the fields in the
890
         "null symbol" allocated at the end of the array.  Note that the
891
         symbol count does *not* include this null symbol, which is why it
892
         is indexed by mcount and not mcount-1. */
893
 
894
      SYMBOL_NAME (&msymbols[mcount]) = NULL;
895
      SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0;
896
      MSYMBOL_INFO (&msymbols[mcount]) = NULL;
897
      MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown;
898
      SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown);
899
 
900
      /* Attach the minimal symbol table to the specified objfile.
901
         The strings themselves are also located in the symbol_obstack
902
         of this objfile.  */
903
 
904
      objfile->minimal_symbol_count = mcount;
905
      objfile->msymbols = msymbols;
906
 
907
      /* Try to guess the appropriate C++ ABI by looking at the names
908
         of the minimal symbols in the table.  */
909
      {
910
        int i;
911
 
912
        for (i = 0; i < mcount; i++)
913
          {
914
            const char *name = SYMBOL_NAME (&objfile->msymbols[i]);
915
            if (name[0] == '_' && name[1] == 'Z')
916
              {
917
                switch_to_cp_abi ("gnu-v3");
918
                break;
919
              }
920
          }
921
      }
922
 
923
      /* Now walk through all the minimal symbols, selecting the newly added
924
         ones and attempting to cache their C++ demangled names. */
925
      for (; mcount-- > 0; msymbols++)
926
        SYMBOL_INIT_DEMANGLED_NAME (msymbols, &objfile->symbol_obstack);
927
 
928
      /* Now build the hash tables; we can't do this incrementally
929
         at an earlier point since we weren't finished with the obstack
930
         yet.  (And if the msymbol obstack gets moved, all the internal
931
         pointers to other msymbols need to be adjusted.) */
932
      build_minimal_symbol_hash_tables (objfile);
933
    }
934
}
935
 
936
/* Sort all the minimal symbols in OBJFILE.  */
937
 
938
void
939
msymbols_sort (struct objfile *objfile)
940
{
941
  qsort (objfile->msymbols, objfile->minimal_symbol_count,
942
         sizeof (struct minimal_symbol), compare_minimal_symbols);
943
  build_minimal_symbol_hash_tables (objfile);
944
}
945
 
946
/* Check if PC is in a shared library trampoline code stub.
947
   Return minimal symbol for the trampoline entry or NULL if PC is not
948
   in a trampoline code stub.  */
949
 
950
struct minimal_symbol *
951
lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
952
{
953
  struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (pc);
954
 
955
  if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
956
    return msymbol;
957
  return NULL;
958
}
959
 
960
/* If PC is in a shared library trampoline code stub, return the
961
   address of the `real' function belonging to the stub.
962
   Return 0 if PC is not in a trampoline code stub or if the real
963
   function is not found in the minimal symbol table.
964
 
965
   We may fail to find the right function if a function with the
966
   same name is defined in more than one shared library, but this
967
   is considered bad programming style. We could return 0 if we find
968
   a duplicate function in case this matters someday.  */
969
 
970
CORE_ADDR
971
find_solib_trampoline_target (CORE_ADDR pc)
972
{
973
  struct objfile *objfile;
974
  struct minimal_symbol *msymbol;
975
  struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
976
 
977
  if (tsymbol != NULL)
978
    {
979
      ALL_MSYMBOLS (objfile, msymbol)
980
      {
981
        if (MSYMBOL_TYPE (msymbol) == mst_text
982
            && STREQ (SYMBOL_NAME (msymbol), SYMBOL_NAME (tsymbol)))
983
          return SYMBOL_VALUE_ADDRESS (msymbol);
984
      }
985
    }
986
  return 0;
987
}

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