1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
3 2002, 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
4 Contributed by Cygnus Support, using pieces from other GDB modules.
6 This file is part of GDB.
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 3 of the License, or
11 (at your option) any later version.
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.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 /* This file contains support routines for creating, manipulating, and
23 destroying minimal symbol tables.
25 Minimal symbol tables are used to hold some very basic information about
26 all defined global symbols (text, data, bss, abs, etc). The only two
27 required pieces of information are the symbol's name and the address
28 associated with that symbol.
30 In many cases, even if a file was compiled with no special options for
31 debugging at all, as long as was not stripped it will contain sufficient
32 information to build useful minimal symbol tables using this structure.
34 Even when a file contains enough debugging information to build a full
35 symbol table, these minimal symbols are still useful for quickly mapping
36 between names and addresses, and vice versa. They are also sometimes used
37 to figure out what full symbol table entries need to be read in. */
42 #include "gdb_string.h"
52 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
53 At the end, copy them all into one newly allocated location on an objfile's
56 #define BUNCH_SIZE 127
60 struct msym_bunch *next;
61 struct minimal_symbol contents[BUNCH_SIZE];
64 /* Bunch currently being filled up.
65 The next field points to chain of filled bunches. */
67 static struct msym_bunch *msym_bunch;
69 /* Number of slots filled in current bunch. */
71 static int msym_bunch_index;
73 /* Total number of minimal symbols recorded so far for the objfile. */
75 static int msym_count;
77 /* Compute a hash code based using the same criteria as `strcmp_iw'. */
80 msymbol_hash_iw (const char *string)
82 unsigned int hash = 0;
83 while (*string && *string != '(')
85 while (isspace (*string))
87 if (*string && *string != '(')
89 hash = hash * 67 + *string - 113;
96 /* Compute a hash code for a string. */
99 msymbol_hash (const char *string)
101 unsigned int hash = 0;
102 for (; *string; ++string)
103 hash = hash * 67 + *string - 113;
107 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
109 add_minsym_to_hash_table (struct minimal_symbol *sym,
110 struct minimal_symbol **table)
112 if (sym->hash_next == NULL)
115 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
116 sym->hash_next = table[hash];
121 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
124 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
125 struct minimal_symbol **table)
127 if (sym->demangled_hash_next == NULL)
130 = msymbol_hash_iw (SYMBOL_SEARCH_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
131 sym->demangled_hash_next = table[hash];
137 /* Return OBJFILE where minimal symbol SYM is defined. */
139 msymbol_objfile (struct minimal_symbol *sym)
141 struct objfile *objf;
142 struct minimal_symbol *tsym;
145 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
147 for (objf = object_files; objf; objf = objf->next)
148 for (tsym = objf->msymbol_hash[hash]; tsym; tsym = tsym->hash_next)
152 /* We should always be able to find the objfile ... */
153 internal_error (__FILE__, __LINE__, _("failed internal consistency check"));
157 /* Look through all the current minimal symbol tables and find the
158 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
159 the search to that objfile. If SFILE is non-NULL, the only file-scope
160 symbols considered will be from that source file (global symbols are
161 still preferred). Returns a pointer to the minimal symbol that
162 matches, or NULL if no match is found.
164 Note: One instance where there may be duplicate minimal symbols with
165 the same name is when the symbol tables for a shared library and the
166 symbol tables for an executable contain global symbols with the same
167 names (the dynamic linker deals with the duplication).
169 It's also possible to have minimal symbols with different mangled
170 names, but identical demangled names. For example, the GNU C++ v3
171 ABI requires the generation of two (or perhaps three) copies of
172 constructor functions --- "in-charge", "not-in-charge", and
173 "allocate" copies; destructors may be duplicated as well.
174 Obviously, there must be distinct mangled names for each of these,
175 but the demangled names are all the same: S::S or S::~S. */
177 struct minimal_symbol *
178 lookup_minimal_symbol (const char *name, const char *sfile,
179 struct objfile *objf)
181 struct objfile *objfile;
182 struct minimal_symbol *msymbol;
183 struct minimal_symbol *found_symbol = NULL;
184 struct minimal_symbol *found_file_symbol = NULL;
185 struct minimal_symbol *trampoline_symbol = NULL;
187 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
188 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
192 char *p = strrchr (sfile, '/');
197 for (objfile = object_files;
198 objfile != NULL && found_symbol == NULL;
199 objfile = objfile->next)
201 if (objf == NULL || objf == objfile
202 || objf->separate_debug_objfile == objfile)
204 /* Do two passes: the first over the ordinary hash table,
205 and the second over the demangled hash table. */
208 for (pass = 1; pass <= 2 && found_symbol == NULL; pass++)
210 /* Select hash list according to pass. */
212 msymbol = objfile->msymbol_hash[hash];
214 msymbol = objfile->msymbol_demangled_hash[dem_hash];
216 while (msymbol != NULL && found_symbol == NULL)
221 match = strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0;
223 match = SYMBOL_MATCHES_SEARCH_NAME (msymbol, name);
226 switch (MSYMBOL_TYPE (msymbol))
232 || strcmp (msymbol->filename, sfile) == 0)
233 found_file_symbol = msymbol;
236 case mst_solib_trampoline:
238 /* If a trampoline symbol is found, we prefer to
239 keep looking for the *real* symbol. If the
240 actual symbol is not found, then we'll use the
242 if (trampoline_symbol == NULL)
243 trampoline_symbol = msymbol;
248 found_symbol = msymbol;
253 /* Find the next symbol on the hash chain. */
255 msymbol = msymbol->hash_next;
257 msymbol = msymbol->demangled_hash_next;
262 /* External symbols are best. */
266 /* File-local symbols are next best. */
267 if (found_file_symbol)
268 return found_file_symbol;
270 /* Symbols for shared library trampolines are next best. */
271 if (trampoline_symbol)
272 return trampoline_symbol;
277 /* Look through all the current minimal symbol tables and find the
278 first minimal symbol that matches NAME and has text type. If OBJF
279 is non-NULL, limit the search to that objfile. Returns a pointer
280 to the minimal symbol that matches, or NULL if no match is found.
282 This function only searches the mangled (linkage) names. */
284 struct minimal_symbol *
285 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
287 struct objfile *objfile;
288 struct minimal_symbol *msymbol;
289 struct minimal_symbol *found_symbol = NULL;
290 struct minimal_symbol *found_file_symbol = NULL;
292 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
294 for (objfile = object_files;
295 objfile != NULL && found_symbol == NULL;
296 objfile = objfile->next)
298 if (objf == NULL || objf == objfile
299 || objf->separate_debug_objfile == objfile)
301 for (msymbol = objfile->msymbol_hash[hash];
302 msymbol != NULL && found_symbol == NULL;
303 msymbol = msymbol->hash_next)
305 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
306 (MSYMBOL_TYPE (msymbol) == mst_text ||
307 MSYMBOL_TYPE (msymbol) == mst_file_text))
309 switch (MSYMBOL_TYPE (msymbol))
312 found_file_symbol = msymbol;
315 found_symbol = msymbol;
322 /* External symbols are best. */
326 /* File-local symbols are next best. */
327 if (found_file_symbol)
328 return found_file_symbol;
333 /* Look through all the current minimal symbol tables and find the
334 first minimal symbol that matches NAME and PC. If OBJF is non-NULL,
335 limit the search to that objfile. Returns a pointer to the minimal
336 symbol that matches, or NULL if no match is found. */
338 struct minimal_symbol *
339 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
340 struct objfile *objf)
342 struct objfile *objfile;
343 struct minimal_symbol *msymbol;
345 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
347 for (objfile = object_files;
349 objfile = objfile->next)
351 if (objf == NULL || objf == objfile
352 || objf->separate_debug_objfile == objfile)
354 for (msymbol = objfile->msymbol_hash[hash];
356 msymbol = msymbol->hash_next)
358 if (SYMBOL_VALUE_ADDRESS (msymbol) == pc
359 && strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0)
368 /* Look through all the current minimal symbol tables and find the
369 first minimal symbol that matches NAME and is a solib trampoline.
370 If OBJF is non-NULL, limit the search to that objfile. Returns a
371 pointer to the minimal symbol that matches, or NULL if no match is
374 This function only searches the mangled (linkage) names. */
376 struct minimal_symbol *
377 lookup_minimal_symbol_solib_trampoline (const char *name,
378 struct objfile *objf)
380 struct objfile *objfile;
381 struct minimal_symbol *msymbol;
382 struct minimal_symbol *found_symbol = NULL;
384 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
386 for (objfile = object_files;
387 objfile != NULL && found_symbol == NULL;
388 objfile = objfile->next)
390 if (objf == NULL || objf == objfile
391 || objf->separate_debug_objfile == objfile)
393 for (msymbol = objfile->msymbol_hash[hash];
394 msymbol != NULL && found_symbol == NULL;
395 msymbol = msymbol->hash_next)
397 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
398 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
407 /* Search through the minimal symbol table for each objfile and find
408 the symbol whose address is the largest address that is still less
409 than or equal to PC, and matches SECTION (if non-NULL). Returns a
410 pointer to the minimal symbol if such a symbol is found, or NULL if
411 PC is not in a suitable range. Note that we need to look through
412 ALL the minimal symbol tables before deciding on the symbol that
413 comes closest to the specified PC. This is because objfiles can
414 overlap, for example objfile A has .text at 0x100 and .data at
415 0x40000 and objfile B has .text at 0x234 and .data at 0x40048.
417 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
418 there are text and trampoline symbols at the same address.
419 Otherwise prefer mst_text symbols. */
421 static struct minimal_symbol *
422 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc,
423 struct obj_section *section,
429 struct objfile *objfile;
430 struct minimal_symbol *msymbol;
431 struct minimal_symbol *best_symbol = NULL;
432 struct obj_section *pc_section;
433 enum minimal_symbol_type want_type, other_type;
435 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
436 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
438 /* PC has to be in a known section. This ensures that anything
439 beyond the end of the last segment doesn't appear to be part of
440 the last function in the last segment. */
441 pc_section = find_pc_section (pc);
442 if (pc_section == NULL)
445 /* We can not require the symbol found to be in pc_section, because
446 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
447 symbol - but find_pc_section won't return an absolute section and
448 hence the code below would skip over absolute symbols. We can
449 still take advantage of the call to find_pc_section, though - the
450 object file still must match. In case we have separate debug
451 files, search both the file and its separate debug file. There's
452 no telling which one will have the minimal symbols. */
454 objfile = pc_section->objfile;
455 if (objfile->separate_debug_objfile)
456 objfile = objfile->separate_debug_objfile;
458 for (; objfile != NULL; objfile = objfile->separate_debug_objfile_backlink)
460 /* If this objfile has a minimal symbol table, go search it using
461 a binary search. Note that a minimal symbol table always consists
462 of at least two symbols, a "real" symbol and the terminating
463 "null symbol". If there are no real symbols, then there is no
464 minimal symbol table at all. */
466 if (objfile->minimal_symbol_count > 0)
468 int best_zero_sized = -1;
470 msymbol = objfile->msymbols;
472 hi = objfile->minimal_symbol_count - 1;
474 /* This code assumes that the minimal symbols are sorted by
475 ascending address values. If the pc value is greater than or
476 equal to the first symbol's address, then some symbol in this
477 minimal symbol table is a suitable candidate for being the
478 "best" symbol. This includes the last real symbol, for cases
479 where the pc value is larger than any address in this vector.
481 By iterating until the address associated with the current
482 hi index (the endpoint of the test interval) is less than
483 or equal to the desired pc value, we accomplish two things:
484 (1) the case where the pc value is larger than any minimal
485 symbol address is trivially solved, (2) the address associated
486 with the hi index is always the one we want when the interation
487 terminates. In essence, we are iterating the test interval
488 down until the pc value is pushed out of it from the high end.
490 Warning: this code is trickier than it would appear at first. */
492 /* Should also require that pc is <= end of objfile. FIXME! */
493 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
495 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
497 /* pc is still strictly less than highest address */
498 /* Note "new" will always be >= lo */
500 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
511 /* If we have multiple symbols at the same address, we want
512 hi to point to the last one. That way we can find the
513 right symbol if it has an index greater than hi. */
514 while (hi < objfile->minimal_symbol_count - 1
515 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
516 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
519 /* Skip various undesirable symbols. */
522 /* Skip any absolute symbols. This is apparently
523 what adb and dbx do, and is needed for the CM-5.
524 There are two known possible problems: (1) on
525 ELF, apparently end, edata, etc. are absolute.
526 Not sure ignoring them here is a big deal, but if
527 we want to use them, the fix would go in
528 elfread.c. (2) I think shared library entry
529 points on the NeXT are absolute. If we want
530 special handling for this it probably should be
531 triggered by a special mst_abs_or_lib or some
534 if (msymbol[hi].type == mst_abs)
540 /* If SECTION was specified, skip any symbol from
543 /* Some types of debug info, such as COFF,
544 don't fill the bfd_section member, so don't
545 throw away symbols on those platforms. */
546 && SYMBOL_OBJ_SECTION (&msymbol[hi]) != NULL
547 && (!matching_obj_sections
548 (SYMBOL_OBJ_SECTION (&msymbol[hi]), section)))
554 /* If we are looking for a trampoline and this is a
555 text symbol, or the other way around, check the
556 preceeding symbol too. If they are otherwise
557 identical prefer that one. */
559 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
560 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
561 && (MSYMBOL_SIZE (&msymbol[hi])
562 == MSYMBOL_SIZE (&msymbol[hi - 1]))
563 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
564 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
565 && (SYMBOL_OBJ_SECTION (&msymbol[hi])
566 == SYMBOL_OBJ_SECTION (&msymbol[hi - 1])))
572 /* If the minimal symbol has a zero size, save it
573 but keep scanning backwards looking for one with
574 a non-zero size. A zero size may mean that the
575 symbol isn't an object or function (e.g. a
576 label), or it may just mean that the size was not
578 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
579 && best_zero_sized == -1)
581 best_zero_sized = hi;
586 /* If we are past the end of the current symbol, try
587 the previous symbol if it has a larger overlapping
588 size. This happens on i686-pc-linux-gnu with glibc;
589 the nocancel variants of system calls are inside
590 the cancellable variants, but both have sizes. */
592 && MSYMBOL_SIZE (&msymbol[hi]) != 0
593 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
594 + MSYMBOL_SIZE (&msymbol[hi]))
595 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
596 + MSYMBOL_SIZE (&msymbol[hi - 1])))
602 /* Otherwise, this symbol must be as good as we're going
607 /* If HI has a zero size, and best_zero_sized is set,
608 then we had two or more zero-sized symbols; prefer
609 the first one we found (which may have a higher
610 address). Also, if we ran off the end, be sure
612 if (best_zero_sized != -1
613 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
614 hi = best_zero_sized;
616 /* If the minimal symbol has a non-zero size, and this
617 PC appears to be outside the symbol's contents, then
618 refuse to use this symbol. If we found a zero-sized
619 symbol with an address greater than this symbol's,
620 use that instead. We assume that if symbols have
621 specified sizes, they do not overlap. */
624 && MSYMBOL_SIZE (&msymbol[hi]) != 0
625 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
626 + MSYMBOL_SIZE (&msymbol[hi])))
628 if (best_zero_sized != -1)
629 hi = best_zero_sized;
631 /* Go on to the next object file. */
635 /* The minimal symbol indexed by hi now is the best one in this
636 objfile's minimal symbol table. See if it is the best one
640 && ((best_symbol == NULL) ||
641 (SYMBOL_VALUE_ADDRESS (best_symbol) <
642 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
644 best_symbol = &msymbol[hi];
649 return (best_symbol);
652 struct minimal_symbol *
653 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
655 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
658 /* Backward compatibility: search through the minimal symbol table
659 for a matching PC (no section given) */
661 struct minimal_symbol *
662 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
664 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
665 force the section but that (well unless you're doing overlay
666 debugging) always returns NULL making the call somewhat useless. */
667 struct obj_section *section = find_pc_section (pc);
670 return lookup_minimal_symbol_by_pc_section (pc, section);
674 /* Return leading symbol character for a BFD. If BFD is NULL,
675 return the leading symbol character from the main objfile. */
677 static int get_symbol_leading_char (bfd *);
680 get_symbol_leading_char (bfd *abfd)
683 return bfd_get_symbol_leading_char (abfd);
684 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
685 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
689 /* Prepare to start collecting minimal symbols. Note that presetting
690 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
691 symbol to allocate the memory for the first bunch. */
694 init_minimal_symbol_collection (void)
698 msym_bunch_index = BUNCH_SIZE;
702 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
703 enum minimal_symbol_type ms_type,
704 struct objfile *objfile)
712 case mst_solib_trampoline:
713 section = SECT_OFF_TEXT (objfile);
717 section = SECT_OFF_DATA (objfile);
721 section = SECT_OFF_BSS (objfile);
727 prim_record_minimal_symbol_and_info (name, address, ms_type,
728 NULL, section, NULL, objfile);
731 /* Record a minimal symbol in the msym bunches. Returns the symbol
734 struct minimal_symbol *
735 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
736 enum minimal_symbol_type ms_type,
737 char *info, int section,
738 asection *bfd_section,
739 struct objfile *objfile)
741 struct obj_section *obj_section;
742 struct msym_bunch *new;
743 struct minimal_symbol *msymbol;
745 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
746 the minimal symbols, because if there is also another symbol
747 at the same address (e.g. the first function of the file),
748 lookup_minimal_symbol_by_pc would have no way of getting the
750 if (ms_type == mst_file_text && name[0] == 'g'
751 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
752 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
755 /* It's safe to strip the leading char here once, since the name
756 is also stored stripped in the minimal symbol table. */
757 if (name[0] == get_symbol_leading_char (objfile->obfd))
760 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
763 if (msym_bunch_index == BUNCH_SIZE)
765 new = (struct msym_bunch *) xmalloc (sizeof (struct msym_bunch));
766 msym_bunch_index = 0;
767 new->next = msym_bunch;
770 msymbol = &msym_bunch->contents[msym_bunch_index];
771 SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown);
772 SYMBOL_LANGUAGE (msymbol) = language_auto;
773 SYMBOL_SET_NAMES (msymbol, (char *)name, strlen (name), objfile);
775 SYMBOL_VALUE_ADDRESS (msymbol) = address;
776 SYMBOL_SECTION (msymbol) = section;
777 SYMBOL_OBJ_SECTION (msymbol) = NULL;
779 /* Find obj_section corresponding to bfd_section. */
781 ALL_OBJFILE_OSECTIONS (objfile, obj_section)
783 if (obj_section->the_bfd_section == bfd_section)
785 SYMBOL_OBJ_SECTION (msymbol) = obj_section;
790 MSYMBOL_TYPE (msymbol) = ms_type;
791 /* FIXME: This info, if it remains, needs its own field. */
792 MSYMBOL_INFO (msymbol) = info; /* FIXME! */
793 MSYMBOL_SIZE (msymbol) = 0;
795 /* The hash pointers must be cleared! If they're not,
796 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
797 msymbol->hash_next = NULL;
798 msymbol->demangled_hash_next = NULL;
802 OBJSTAT (objfile, n_minsyms++);
806 /* Compare two minimal symbols by address and return a signed result based
807 on unsigned comparisons, so that we sort into unsigned numeric order.
808 Within groups with the same address, sort by name. */
811 compare_minimal_symbols (const void *fn1p, const void *fn2p)
813 const struct minimal_symbol *fn1;
814 const struct minimal_symbol *fn2;
816 fn1 = (const struct minimal_symbol *) fn1p;
817 fn2 = (const struct minimal_symbol *) fn2p;
819 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
821 return (-1); /* addr 1 is less than addr 2 */
823 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
825 return (1); /* addr 1 is greater than addr 2 */
828 /* addrs are equal: sort by name */
830 char *name1 = SYMBOL_LINKAGE_NAME (fn1);
831 char *name2 = SYMBOL_LINKAGE_NAME (fn2);
833 if (name1 && name2) /* both have names */
834 return strcmp (name1, name2);
836 return 1; /* fn1 has no name, so it is "less" */
837 else if (name1) /* fn2 has no name, so it is "less" */
840 return (0); /* neither has a name, so they're equal. */
844 /* Discard the currently collected minimal symbols, if any. If we wish
845 to save them for later use, we must have already copied them somewhere
846 else before calling this function.
848 FIXME: We could allocate the minimal symbol bunches on their own
849 obstack and then simply blow the obstack away when we are done with
850 it. Is it worth the extra trouble though? */
853 do_discard_minimal_symbols_cleanup (void *arg)
855 struct msym_bunch *next;
857 while (msym_bunch != NULL)
859 next = msym_bunch->next;
866 make_cleanup_discard_minimal_symbols (void)
868 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
873 /* Compact duplicate entries out of a minimal symbol table by walking
874 through the table and compacting out entries with duplicate addresses
875 and matching names. Return the number of entries remaining.
877 On entry, the table resides between msymbol[0] and msymbol[mcount].
878 On exit, it resides between msymbol[0] and msymbol[result_count].
880 When files contain multiple sources of symbol information, it is
881 possible for the minimal symbol table to contain many duplicate entries.
882 As an example, SVR4 systems use ELF formatted object files, which
883 usually contain at least two different types of symbol tables (a
884 standard ELF one and a smaller dynamic linking table), as well as
885 DWARF debugging information for files compiled with -g.
887 Without compacting, the minimal symbol table for gdb itself contains
888 over a 1000 duplicates, about a third of the total table size. Aside
889 from the potential trap of not noticing that two successive entries
890 identify the same location, this duplication impacts the time required
891 to linearly scan the table, which is done in a number of places. So we
892 just do one linear scan here and toss out the duplicates.
894 Note that we are not concerned here about recovering the space that
895 is potentially freed up, because the strings themselves are allocated
896 on the objfile_obstack, and will get automatically freed when the symbol
897 table is freed. The caller can free up the unused minimal symbols at
898 the end of the compacted region if their allocation strategy allows it.
900 Also note we only go up to the next to last entry within the loop
901 and then copy the last entry explicitly after the loop terminates.
903 Since the different sources of information for each symbol may
904 have different levels of "completeness", we may have duplicates
905 that have one entry with type "mst_unknown" and the other with a
906 known type. So if the one we are leaving alone has type mst_unknown,
907 overwrite its type with the type from the one we are compacting out. */
910 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
911 struct objfile *objfile)
913 struct minimal_symbol *copyfrom;
914 struct minimal_symbol *copyto;
918 copyfrom = copyto = msymbol;
919 while (copyfrom < msymbol + mcount - 1)
921 if (SYMBOL_VALUE_ADDRESS (copyfrom)
922 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
923 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
924 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
926 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
928 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
933 *copyto++ = *copyfrom++;
935 *copyto++ = *copyfrom++;
936 mcount = copyto - msymbol;
941 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
942 after compacting or sorting the table since the entries move around
943 thus causing the internal minimal_symbol pointers to become jumbled. */
946 build_minimal_symbol_hash_tables (struct objfile *objfile)
949 struct minimal_symbol *msym;
951 /* Clear the hash tables. */
952 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
954 objfile->msymbol_hash[i] = 0;
955 objfile->msymbol_demangled_hash[i] = 0;
958 /* Now, (re)insert the actual entries. */
959 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
964 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
966 msym->demangled_hash_next = 0;
967 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
968 add_minsym_to_demangled_hash_table (msym,
969 objfile->msymbol_demangled_hash);
973 /* Add the minimal symbols in the existing bunches to the objfile's official
974 minimal symbol table. In most cases there is no minimal symbol table yet
975 for this objfile, and the existing bunches are used to create one. Once
976 in a while (for shared libraries for example), we add symbols (e.g. common
977 symbols) to an existing objfile.
979 Because of the way minimal symbols are collected, we generally have no way
980 of knowing what source language applies to any particular minimal symbol.
981 Specifically, we have no way of knowing if the minimal symbol comes from a
982 C++ compilation unit or not. So for the sake of supporting cached
983 demangled C++ names, we have no choice but to try and demangle each new one
984 that comes in. If the demangling succeeds, then we assume it is a C++
985 symbol and set the symbol's language and demangled name fields
986 appropriately. Note that in order to avoid unnecessary demanglings, and
987 allocating obstack space that subsequently can't be freed for the demangled
988 names, we mark all newly added symbols with language_auto. After
989 compaction of the minimal symbols, we go back and scan the entire minimal
990 symbol table looking for these new symbols. For each new symbol we attempt
991 to demangle it, and if successful, record it as a language_cplus symbol
992 and cache the demangled form on the symbol obstack. Symbols which don't
993 demangle are marked as language_unknown symbols, which inhibits future
994 attempts to demangle them if we later add more minimal symbols. */
997 install_minimal_symbols (struct objfile *objfile)
1001 struct msym_bunch *bunch;
1002 struct minimal_symbol *msymbols;
1007 /* Allocate enough space in the obstack, into which we will gather the
1008 bunches of new and existing minimal symbols, sort them, and then
1009 compact out the duplicate entries. Once we have a final table,
1010 we will give back the excess space. */
1012 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1013 obstack_blank (&objfile->objfile_obstack,
1014 alloc_count * sizeof (struct minimal_symbol));
1015 msymbols = (struct minimal_symbol *)
1016 obstack_base (&objfile->objfile_obstack);
1018 /* Copy in the existing minimal symbols, if there are any. */
1020 if (objfile->minimal_symbol_count)
1021 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1022 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1024 /* Walk through the list of minimal symbol bunches, adding each symbol
1025 to the new contiguous array of symbols. Note that we start with the
1026 current, possibly partially filled bunch (thus we use the current
1027 msym_bunch_index for the first bunch we copy over), and thereafter
1028 each bunch is full. */
1030 mcount = objfile->minimal_symbol_count;
1032 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1034 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1035 msymbols[mcount] = bunch->contents[bindex];
1036 msym_bunch_index = BUNCH_SIZE;
1039 /* Sort the minimal symbols by address. */
1041 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1042 compare_minimal_symbols);
1044 /* Compact out any duplicates, and free up whatever space we are
1047 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1049 obstack_blank (&objfile->objfile_obstack,
1050 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1051 msymbols = (struct minimal_symbol *)
1052 obstack_finish (&objfile->objfile_obstack);
1054 /* We also terminate the minimal symbol table with a "null symbol",
1055 which is *not* included in the size of the table. This makes it
1056 easier to find the end of the table when we are handed a pointer
1057 to some symbol in the middle of it. Zero out the fields in the
1058 "null symbol" allocated at the end of the array. Note that the
1059 symbol count does *not* include this null symbol, which is why it
1060 is indexed by mcount and not mcount-1. */
1062 SYMBOL_LINKAGE_NAME (&msymbols[mcount]) = NULL;
1063 SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0;
1064 MSYMBOL_INFO (&msymbols[mcount]) = NULL;
1065 MSYMBOL_SIZE (&msymbols[mcount]) = 0;
1066 MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown;
1067 SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown);
1069 /* Attach the minimal symbol table to the specified objfile.
1070 The strings themselves are also located in the objfile_obstack
1073 objfile->minimal_symbol_count = mcount;
1074 objfile->msymbols = msymbols;
1076 /* Try to guess the appropriate C++ ABI by looking at the names
1077 of the minimal symbols in the table. */
1081 for (i = 0; i < mcount; i++)
1083 /* If a symbol's name starts with _Z and was successfully
1084 demangled, then we can assume we've found a GNU v3 symbol.
1085 For now we set the C++ ABI globally; if the user is
1086 mixing ABIs then the user will need to "set cp-abi"
1088 const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]);
1089 if (name[0] == '_' && name[1] == 'Z'
1090 && SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL)
1092 set_cp_abi_as_auto_default ("gnu-v3");
1098 /* Now build the hash tables; we can't do this incrementally
1099 at an earlier point since we weren't finished with the obstack
1100 yet. (And if the msymbol obstack gets moved, all the internal
1101 pointers to other msymbols need to be adjusted.) */
1102 build_minimal_symbol_hash_tables (objfile);
1106 /* Sort all the minimal symbols in OBJFILE. */
1109 msymbols_sort (struct objfile *objfile)
1111 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1112 sizeof (struct minimal_symbol), compare_minimal_symbols);
1113 build_minimal_symbol_hash_tables (objfile);
1116 /* Check if PC is in a shared library trampoline code stub.
1117 Return minimal symbol for the trampoline entry or NULL if PC is not
1118 in a trampoline code stub. */
1120 struct minimal_symbol *
1121 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1123 struct obj_section *section = find_pc_section (pc);
1124 struct minimal_symbol *msymbol;
1126 if (section == NULL)
1128 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1130 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
1135 /* If PC is in a shared library trampoline code stub, return the
1136 address of the `real' function belonging to the stub.
1137 Return 0 if PC is not in a trampoline code stub or if the real
1138 function is not found in the minimal symbol table.
1140 We may fail to find the right function if a function with the
1141 same name is defined in more than one shared library, but this
1142 is considered bad programming style. We could return 0 if we find
1143 a duplicate function in case this matters someday. */
1146 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1148 struct objfile *objfile;
1149 struct minimal_symbol *msymbol;
1150 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1152 if (tsymbol != NULL)
1154 ALL_MSYMBOLS (objfile, msymbol)
1156 if (MSYMBOL_TYPE (msymbol) == mst_text
1157 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1158 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1159 return SYMBOL_VALUE_ADDRESS (msymbol);
1161 /* Also handle minimal symbols pointing to function descriptors. */
1162 if (MSYMBOL_TYPE (msymbol) == mst_data
1163 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1164 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1167 func = gdbarch_convert_from_func_ptr_addr
1168 (get_objfile_arch (objfile),
1169 SYMBOL_VALUE_ADDRESS (msymbol),
1172 /* Ignore data symbols that are not function descriptors. */
1173 if (func != SYMBOL_VALUE_ADDRESS (msymbol))