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