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, 2009 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"
51 #include "cp-support.h"
54 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
55 At the end, copy them all into one newly allocated location on an objfile's
58 #define BUNCH_SIZE 127
62 struct msym_bunch *next;
63 struct minimal_symbol contents[BUNCH_SIZE];
66 /* Bunch currently being filled up.
67 The next field points to chain of filled bunches. */
69 static struct msym_bunch *msym_bunch;
71 /* Number of slots filled in current bunch. */
73 static int msym_bunch_index;
75 /* Total number of minimal symbols recorded so far for the objfile. */
77 static int msym_count;
79 /* Compute a hash code based using the same criteria as `strcmp_iw'. */
82 msymbol_hash_iw (const char *string)
84 unsigned int hash = 0;
85 while (*string && *string != '(')
87 while (isspace (*string))
89 if (*string && *string != '(')
91 hash = hash * 67 + *string - 113;
98 /* Compute a hash code for a string. */
101 msymbol_hash (const char *string)
103 unsigned int hash = 0;
104 for (; *string; ++string)
105 hash = hash * 67 + *string - 113;
109 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
111 add_minsym_to_hash_table (struct minimal_symbol *sym,
112 struct minimal_symbol **table)
114 if (sym->hash_next == NULL)
117 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
118 sym->hash_next = table[hash];
123 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
126 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
127 struct minimal_symbol **table)
129 if (sym->demangled_hash_next == NULL)
132 = msymbol_hash_iw (SYMBOL_SEARCH_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
133 sym->demangled_hash_next = table[hash];
139 /* Return OBJFILE where minimal symbol SYM is defined. */
141 msymbol_objfile (struct minimal_symbol *sym)
143 struct objfile *objf;
144 struct minimal_symbol *tsym;
147 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
149 for (objf = object_files; objf; objf = objf->next)
150 for (tsym = objf->msymbol_hash[hash]; tsym; tsym = tsym->hash_next)
154 /* We should always be able to find the objfile ... */
155 internal_error (__FILE__, __LINE__, _("failed internal consistency check"));
159 /* Look through all the current minimal symbol tables and find the
160 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
161 the search to that objfile. If SFILE is non-NULL, the only file-scope
162 symbols considered will be from that source file (global symbols are
163 still preferred). Returns a pointer to the minimal symbol that
164 matches, or NULL if no match is found.
166 Note: One instance where there may be duplicate minimal symbols with
167 the same name is when the symbol tables for a shared library and the
168 symbol tables for an executable contain global symbols with the same
169 names (the dynamic linker deals with the duplication).
171 It's also possible to have minimal symbols with different mangled
172 names, but identical demangled names. For example, the GNU C++ v3
173 ABI requires the generation of two (or perhaps three) copies of
174 constructor functions --- "in-charge", "not-in-charge", and
175 "allocate" copies; destructors may be duplicated as well.
176 Obviously, there must be distinct mangled names for each of these,
177 but the demangled names are all the same: S::S or S::~S. */
179 struct minimal_symbol *
180 lookup_minimal_symbol (const char *name, const char *sfile,
181 struct objfile *objf)
183 struct objfile *objfile;
184 struct minimal_symbol *msymbol;
185 struct minimal_symbol *found_symbol = NULL;
186 struct minimal_symbol *found_file_symbol = NULL;
187 struct minimal_symbol *trampoline_symbol = NULL;
189 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
190 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
192 int needtofreename = 0;
193 const char *modified_name;
197 char *p = strrchr (sfile, '/');
202 /* For C++, canonicalize the input name. */
203 modified_name = name;
204 if (current_language->la_language == language_cplus)
206 char *cname = cp_canonicalize_string (name);
209 modified_name = cname;
214 for (objfile = object_files;
215 objfile != NULL && found_symbol == NULL;
216 objfile = objfile->next)
218 if (objf == NULL || objf == objfile
219 || objf->separate_debug_objfile == objfile)
221 /* Do two passes: the first over the ordinary hash table,
222 and the second over the demangled hash table. */
225 for (pass = 1; pass <= 2 && found_symbol == NULL; pass++)
227 /* Select hash list according to pass. */
229 msymbol = objfile->msymbol_hash[hash];
231 msymbol = objfile->msymbol_demangled_hash[dem_hash];
233 while (msymbol != NULL && found_symbol == NULL)
239 match = strcmp (SYMBOL_LINKAGE_NAME (msymbol),
244 match = SYMBOL_MATCHES_SEARCH_NAME (msymbol,
250 switch (MSYMBOL_TYPE (msymbol))
256 || strcmp (msymbol->filename, sfile) == 0)
257 found_file_symbol = msymbol;
260 case mst_solib_trampoline:
262 /* If a trampoline symbol is found, we prefer to
263 keep looking for the *real* symbol. If the
264 actual symbol is not found, then we'll use the
266 if (trampoline_symbol == NULL)
267 trampoline_symbol = msymbol;
272 found_symbol = msymbol;
277 /* Find the next symbol on the hash chain. */
279 msymbol = msymbol->hash_next;
281 msymbol = msymbol->demangled_hash_next;
288 xfree ((void *) modified_name);
290 /* External symbols are best. */
294 /* File-local symbols are next best. */
295 if (found_file_symbol)
296 return found_file_symbol;
298 /* Symbols for shared library trampolines are next best. */
299 if (trampoline_symbol)
300 return trampoline_symbol;
305 /* Look through all the current minimal symbol tables and find the
306 first minimal symbol that matches NAME and has text type. If OBJF
307 is non-NULL, limit the search to that objfile. Returns a pointer
308 to the minimal symbol that matches, or NULL if no match is found.
310 This function only searches the mangled (linkage) names. */
312 struct minimal_symbol *
313 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
315 struct objfile *objfile;
316 struct minimal_symbol *msymbol;
317 struct minimal_symbol *found_symbol = NULL;
318 struct minimal_symbol *found_file_symbol = NULL;
320 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
322 for (objfile = object_files;
323 objfile != NULL && found_symbol == NULL;
324 objfile = objfile->next)
326 if (objf == NULL || objf == objfile
327 || objf->separate_debug_objfile == objfile)
329 for (msymbol = objfile->msymbol_hash[hash];
330 msymbol != NULL && found_symbol == NULL;
331 msymbol = msymbol->hash_next)
333 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
334 (MSYMBOL_TYPE (msymbol) == mst_text ||
335 MSYMBOL_TYPE (msymbol) == mst_file_text))
337 switch (MSYMBOL_TYPE (msymbol))
340 found_file_symbol = msymbol;
343 found_symbol = msymbol;
350 /* External symbols are best. */
354 /* File-local symbols are next best. */
355 if (found_file_symbol)
356 return found_file_symbol;
361 /* Look through all the current minimal symbol tables and find the
362 first minimal symbol that matches NAME and PC. If OBJF is non-NULL,
363 limit the search to that objfile. Returns a pointer to the minimal
364 symbol that matches, or NULL if no match is found. */
366 struct minimal_symbol *
367 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
368 struct objfile *objf)
370 struct objfile *objfile;
371 struct minimal_symbol *msymbol;
373 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
375 for (objfile = object_files;
377 objfile = objfile->next)
379 if (objf == NULL || objf == objfile
380 || objf->separate_debug_objfile == objfile)
382 for (msymbol = objfile->msymbol_hash[hash];
384 msymbol = msymbol->hash_next)
386 if (SYMBOL_VALUE_ADDRESS (msymbol) == pc
387 && strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0)
396 /* Look through all the current minimal symbol tables and find the
397 first minimal symbol that matches NAME and is a solib trampoline.
398 If OBJF is non-NULL, limit the search to that objfile. Returns a
399 pointer to the minimal symbol that matches, or NULL if no match is
402 This function only searches the mangled (linkage) names. */
404 struct minimal_symbol *
405 lookup_minimal_symbol_solib_trampoline (const char *name,
406 struct objfile *objf)
408 struct objfile *objfile;
409 struct minimal_symbol *msymbol;
410 struct minimal_symbol *found_symbol = NULL;
412 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
414 for (objfile = object_files;
415 objfile != NULL && found_symbol == NULL;
416 objfile = objfile->next)
418 if (objf == NULL || objf == objfile
419 || objf->separate_debug_objfile == objfile)
421 for (msymbol = objfile->msymbol_hash[hash];
422 msymbol != NULL && found_symbol == NULL;
423 msymbol = msymbol->hash_next)
425 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
426 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
435 /* Search through the minimal symbol table for each objfile and find
436 the symbol whose address is the largest address that is still less
437 than or equal to PC, and matches SECTION (which is not NULL).
438 Returns a pointer to the minimal symbol if such a symbol is found,
439 or NULL if PC is not in a suitable range.
440 Note that we need to look through ALL the minimal symbol tables
441 before deciding on the symbol that comes closest to the specified PC.
442 This is because objfiles can overlap, for example objfile A has .text
443 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
446 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
447 there are text and trampoline symbols at the same address.
448 Otherwise prefer mst_text symbols. */
450 static struct minimal_symbol *
451 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc,
452 struct obj_section *section,
458 struct objfile *objfile;
459 struct minimal_symbol *msymbol;
460 struct minimal_symbol *best_symbol = NULL;
461 enum minimal_symbol_type want_type, other_type;
463 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
464 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
466 /* We can not require the symbol found to be in section, because
467 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
468 symbol - but find_pc_section won't return an absolute section and
469 hence the code below would skip over absolute symbols. We can
470 still take advantage of the call to find_pc_section, though - the
471 object file still must match. In case we have separate debug
472 files, search both the file and its separate debug file. There's
473 no telling which one will have the minimal symbols. */
475 gdb_assert (section != NULL);
476 objfile = section->objfile;
477 if (objfile->separate_debug_objfile)
478 objfile = objfile->separate_debug_objfile;
480 for (; objfile != NULL; objfile = objfile->separate_debug_objfile_backlink)
482 /* If this objfile has a minimal symbol table, go search it using
483 a binary search. Note that a minimal symbol table always consists
484 of at least two symbols, a "real" symbol and the terminating
485 "null symbol". If there are no real symbols, then there is no
486 minimal symbol table at all. */
488 if (objfile->minimal_symbol_count > 0)
490 int best_zero_sized = -1;
492 msymbol = objfile->msymbols;
494 hi = objfile->minimal_symbol_count - 1;
496 /* This code assumes that the minimal symbols are sorted by
497 ascending address values. If the pc value is greater than or
498 equal to the first symbol's address, then some symbol in this
499 minimal symbol table is a suitable candidate for being the
500 "best" symbol. This includes the last real symbol, for cases
501 where the pc value is larger than any address in this vector.
503 By iterating until the address associated with the current
504 hi index (the endpoint of the test interval) is less than
505 or equal to the desired pc value, we accomplish two things:
506 (1) the case where the pc value is larger than any minimal
507 symbol address is trivially solved, (2) the address associated
508 with the hi index is always the one we want when the interation
509 terminates. In essence, we are iterating the test interval
510 down until the pc value is pushed out of it from the high end.
512 Warning: this code is trickier than it would appear at first. */
514 /* Should also require that pc is <= end of objfile. FIXME! */
515 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
517 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
519 /* pc is still strictly less than highest address */
520 /* Note "new" will always be >= lo */
522 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
533 /* If we have multiple symbols at the same address, we want
534 hi to point to the last one. That way we can find the
535 right symbol if it has an index greater than hi. */
536 while (hi < objfile->minimal_symbol_count - 1
537 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
538 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
541 /* Skip various undesirable symbols. */
544 /* Skip any absolute symbols. This is apparently
545 what adb and dbx do, and is needed for the CM-5.
546 There are two known possible problems: (1) on
547 ELF, apparently end, edata, etc. are absolute.
548 Not sure ignoring them here is a big deal, but if
549 we want to use them, the fix would go in
550 elfread.c. (2) I think shared library entry
551 points on the NeXT are absolute. If we want
552 special handling for this it probably should be
553 triggered by a special mst_abs_or_lib or some
556 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
562 /* If SECTION was specified, skip any symbol from
565 /* Some types of debug info, such as COFF,
566 don't fill the bfd_section member, so don't
567 throw away symbols on those platforms. */
568 && SYMBOL_OBJ_SECTION (&msymbol[hi]) != NULL
569 && (!matching_obj_sections
570 (SYMBOL_OBJ_SECTION (&msymbol[hi]), section)))
576 /* If we are looking for a trampoline and this is a
577 text symbol, or the other way around, check the
578 preceeding symbol too. If they are otherwise
579 identical prefer that one. */
581 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
582 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
583 && (MSYMBOL_SIZE (&msymbol[hi])
584 == MSYMBOL_SIZE (&msymbol[hi - 1]))
585 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
586 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
587 && (SYMBOL_OBJ_SECTION (&msymbol[hi])
588 == SYMBOL_OBJ_SECTION (&msymbol[hi - 1])))
594 /* If the minimal symbol has a zero size, save it
595 but keep scanning backwards looking for one with
596 a non-zero size. A zero size may mean that the
597 symbol isn't an object or function (e.g. a
598 label), or it may just mean that the size was not
600 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
601 && best_zero_sized == -1)
603 best_zero_sized = hi;
608 /* If we are past the end of the current symbol, try
609 the previous symbol if it has a larger overlapping
610 size. This happens on i686-pc-linux-gnu with glibc;
611 the nocancel variants of system calls are inside
612 the cancellable variants, but both have sizes. */
614 && MSYMBOL_SIZE (&msymbol[hi]) != 0
615 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
616 + MSYMBOL_SIZE (&msymbol[hi]))
617 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
618 + MSYMBOL_SIZE (&msymbol[hi - 1])))
624 /* Otherwise, this symbol must be as good as we're going
629 /* If HI has a zero size, and best_zero_sized is set,
630 then we had two or more zero-sized symbols; prefer
631 the first one we found (which may have a higher
632 address). Also, if we ran off the end, be sure
634 if (best_zero_sized != -1
635 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
636 hi = best_zero_sized;
638 /* If the minimal symbol has a non-zero size, and this
639 PC appears to be outside the symbol's contents, then
640 refuse to use this symbol. If we found a zero-sized
641 symbol with an address greater than this symbol's,
642 use that instead. We assume that if symbols have
643 specified sizes, they do not overlap. */
646 && MSYMBOL_SIZE (&msymbol[hi]) != 0
647 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
648 + MSYMBOL_SIZE (&msymbol[hi])))
650 if (best_zero_sized != -1)
651 hi = best_zero_sized;
653 /* Go on to the next object file. */
657 /* The minimal symbol indexed by hi now is the best one in this
658 objfile's minimal symbol table. See if it is the best one
662 && ((best_symbol == NULL) ||
663 (SYMBOL_VALUE_ADDRESS (best_symbol) <
664 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
666 best_symbol = &msymbol[hi];
671 return (best_symbol);
674 struct minimal_symbol *
675 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
679 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
680 force the section but that (well unless you're doing overlay
681 debugging) always returns NULL making the call somewhat useless. */
682 section = find_pc_section (pc);
686 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
689 /* Backward compatibility: search through the minimal symbol table
690 for a matching PC (no section given) */
692 struct minimal_symbol *
693 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
695 return lookup_minimal_symbol_by_pc_section (pc, NULL);
699 /* Return leading symbol character for a BFD. If BFD is NULL,
700 return the leading symbol character from the main objfile. */
702 static int get_symbol_leading_char (bfd *);
705 get_symbol_leading_char (bfd *abfd)
708 return bfd_get_symbol_leading_char (abfd);
709 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
710 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
714 /* Prepare to start collecting minimal symbols. Note that presetting
715 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
716 symbol to allocate the memory for the first bunch. */
719 init_minimal_symbol_collection (void)
723 msym_bunch_index = BUNCH_SIZE;
727 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
728 enum minimal_symbol_type ms_type,
729 struct objfile *objfile)
737 case mst_solib_trampoline:
738 section = SECT_OFF_TEXT (objfile);
742 section = SECT_OFF_DATA (objfile);
746 section = SECT_OFF_BSS (objfile);
752 prim_record_minimal_symbol_and_info (name, address, ms_type,
753 section, NULL, objfile);
756 /* Record a minimal symbol in the msym bunches. Returns the symbol
759 struct minimal_symbol *
760 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
761 enum minimal_symbol_type ms_type,
763 asection *bfd_section,
764 struct objfile *objfile)
766 struct obj_section *obj_section;
767 struct msym_bunch *new;
768 struct minimal_symbol *msymbol;
770 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
771 the minimal symbols, because if there is also another symbol
772 at the same address (e.g. the first function of the file),
773 lookup_minimal_symbol_by_pc would have no way of getting the
775 if (ms_type == mst_file_text && name[0] == 'g'
776 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
777 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
780 /* It's safe to strip the leading char here once, since the name
781 is also stored stripped in the minimal symbol table. */
782 if (name[0] == get_symbol_leading_char (objfile->obfd))
785 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
788 if (msym_bunch_index == BUNCH_SIZE)
790 new = XCALLOC (1, struct msym_bunch);
791 msym_bunch_index = 0;
792 new->next = msym_bunch;
795 msymbol = &msym_bunch->contents[msym_bunch_index];
796 SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown);
797 SYMBOL_LANGUAGE (msymbol) = language_auto;
798 SYMBOL_SET_NAMES (msymbol, (char *)name, strlen (name), objfile);
800 SYMBOL_VALUE_ADDRESS (msymbol) = address;
801 SYMBOL_SECTION (msymbol) = section;
802 SYMBOL_OBJ_SECTION (msymbol) = NULL;
804 /* Find obj_section corresponding to bfd_section. */
806 ALL_OBJFILE_OSECTIONS (objfile, obj_section)
808 if (obj_section->the_bfd_section == bfd_section)
810 SYMBOL_OBJ_SECTION (msymbol) = obj_section;
815 MSYMBOL_TYPE (msymbol) = ms_type;
816 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
817 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
818 MSYMBOL_SIZE (msymbol) = 0;
820 /* The hash pointers must be cleared! If they're not,
821 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
822 msymbol->hash_next = NULL;
823 msymbol->demangled_hash_next = NULL;
827 OBJSTAT (objfile, n_minsyms++);
831 /* Compare two minimal symbols by address and return a signed result based
832 on unsigned comparisons, so that we sort into unsigned numeric order.
833 Within groups with the same address, sort by name. */
836 compare_minimal_symbols (const void *fn1p, const void *fn2p)
838 const struct minimal_symbol *fn1;
839 const struct minimal_symbol *fn2;
841 fn1 = (const struct minimal_symbol *) fn1p;
842 fn2 = (const struct minimal_symbol *) fn2p;
844 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
846 return (-1); /* addr 1 is less than addr 2 */
848 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
850 return (1); /* addr 1 is greater than addr 2 */
853 /* addrs are equal: sort by name */
855 char *name1 = SYMBOL_LINKAGE_NAME (fn1);
856 char *name2 = SYMBOL_LINKAGE_NAME (fn2);
858 if (name1 && name2) /* both have names */
859 return strcmp (name1, name2);
861 return 1; /* fn1 has no name, so it is "less" */
862 else if (name1) /* fn2 has no name, so it is "less" */
865 return (0); /* neither has a name, so they're equal. */
869 /* Discard the currently collected minimal symbols, if any. If we wish
870 to save them for later use, we must have already copied them somewhere
871 else before calling this function.
873 FIXME: We could allocate the minimal symbol bunches on their own
874 obstack and then simply blow the obstack away when we are done with
875 it. Is it worth the extra trouble though? */
878 do_discard_minimal_symbols_cleanup (void *arg)
880 struct msym_bunch *next;
882 while (msym_bunch != NULL)
884 next = msym_bunch->next;
891 make_cleanup_discard_minimal_symbols (void)
893 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
898 /* Compact duplicate entries out of a minimal symbol table by walking
899 through the table and compacting out entries with duplicate addresses
900 and matching names. Return the number of entries remaining.
902 On entry, the table resides between msymbol[0] and msymbol[mcount].
903 On exit, it resides between msymbol[0] and msymbol[result_count].
905 When files contain multiple sources of symbol information, it is
906 possible for the minimal symbol table to contain many duplicate entries.
907 As an example, SVR4 systems use ELF formatted object files, which
908 usually contain at least two different types of symbol tables (a
909 standard ELF one and a smaller dynamic linking table), as well as
910 DWARF debugging information for files compiled with -g.
912 Without compacting, the minimal symbol table for gdb itself contains
913 over a 1000 duplicates, about a third of the total table size. Aside
914 from the potential trap of not noticing that two successive entries
915 identify the same location, this duplication impacts the time required
916 to linearly scan the table, which is done in a number of places. So we
917 just do one linear scan here and toss out the duplicates.
919 Note that we are not concerned here about recovering the space that
920 is potentially freed up, because the strings themselves are allocated
921 on the objfile_obstack, and will get automatically freed when the symbol
922 table is freed. The caller can free up the unused minimal symbols at
923 the end of the compacted region if their allocation strategy allows it.
925 Also note we only go up to the next to last entry within the loop
926 and then copy the last entry explicitly after the loop terminates.
928 Since the different sources of information for each symbol may
929 have different levels of "completeness", we may have duplicates
930 that have one entry with type "mst_unknown" and the other with a
931 known type. So if the one we are leaving alone has type mst_unknown,
932 overwrite its type with the type from the one we are compacting out. */
935 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
936 struct objfile *objfile)
938 struct minimal_symbol *copyfrom;
939 struct minimal_symbol *copyto;
943 copyfrom = copyto = msymbol;
944 while (copyfrom < msymbol + mcount - 1)
946 if (SYMBOL_VALUE_ADDRESS (copyfrom)
947 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
948 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
949 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
951 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
953 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
958 *copyto++ = *copyfrom++;
960 *copyto++ = *copyfrom++;
961 mcount = copyto - msymbol;
966 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
967 after compacting or sorting the table since the entries move around
968 thus causing the internal minimal_symbol pointers to become jumbled. */
971 build_minimal_symbol_hash_tables (struct objfile *objfile)
974 struct minimal_symbol *msym;
976 /* Clear the hash tables. */
977 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
979 objfile->msymbol_hash[i] = 0;
980 objfile->msymbol_demangled_hash[i] = 0;
983 /* Now, (re)insert the actual entries. */
984 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
989 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
991 msym->demangled_hash_next = 0;
992 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
993 add_minsym_to_demangled_hash_table (msym,
994 objfile->msymbol_demangled_hash);
998 /* Add the minimal symbols in the existing bunches to the objfile's official
999 minimal symbol table. In most cases there is no minimal symbol table yet
1000 for this objfile, and the existing bunches are used to create one. Once
1001 in a while (for shared libraries for example), we add symbols (e.g. common
1002 symbols) to an existing objfile.
1004 Because of the way minimal symbols are collected, we generally have no way
1005 of knowing what source language applies to any particular minimal symbol.
1006 Specifically, we have no way of knowing if the minimal symbol comes from a
1007 C++ compilation unit or not. So for the sake of supporting cached
1008 demangled C++ names, we have no choice but to try and demangle each new one
1009 that comes in. If the demangling succeeds, then we assume it is a C++
1010 symbol and set the symbol's language and demangled name fields
1011 appropriately. Note that in order to avoid unnecessary demanglings, and
1012 allocating obstack space that subsequently can't be freed for the demangled
1013 names, we mark all newly added symbols with language_auto. After
1014 compaction of the minimal symbols, we go back and scan the entire minimal
1015 symbol table looking for these new symbols. For each new symbol we attempt
1016 to demangle it, and if successful, record it as a language_cplus symbol
1017 and cache the demangled form on the symbol obstack. Symbols which don't
1018 demangle are marked as language_unknown symbols, which inhibits future
1019 attempts to demangle them if we later add more minimal symbols. */
1022 install_minimal_symbols (struct objfile *objfile)
1026 struct msym_bunch *bunch;
1027 struct minimal_symbol *msymbols;
1032 /* Allocate enough space in the obstack, into which we will gather the
1033 bunches of new and existing minimal symbols, sort them, and then
1034 compact out the duplicate entries. Once we have a final table,
1035 we will give back the excess space. */
1037 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1038 obstack_blank (&objfile->objfile_obstack,
1039 alloc_count * sizeof (struct minimal_symbol));
1040 msymbols = (struct minimal_symbol *)
1041 obstack_base (&objfile->objfile_obstack);
1043 /* Copy in the existing minimal symbols, if there are any. */
1045 if (objfile->minimal_symbol_count)
1046 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1047 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1049 /* Walk through the list of minimal symbol bunches, adding each symbol
1050 to the new contiguous array of symbols. Note that we start with the
1051 current, possibly partially filled bunch (thus we use the current
1052 msym_bunch_index for the first bunch we copy over), and thereafter
1053 each bunch is full. */
1055 mcount = objfile->minimal_symbol_count;
1057 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1059 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1060 msymbols[mcount] = bunch->contents[bindex];
1061 msym_bunch_index = BUNCH_SIZE;
1064 /* Sort the minimal symbols by address. */
1066 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1067 compare_minimal_symbols);
1069 /* Compact out any duplicates, and free up whatever space we are
1072 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1074 obstack_blank (&objfile->objfile_obstack,
1075 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1076 msymbols = (struct minimal_symbol *)
1077 obstack_finish (&objfile->objfile_obstack);
1079 /* We also terminate the minimal symbol table with a "null symbol",
1080 which is *not* included in the size of the table. This makes it
1081 easier to find the end of the table when we are handed a pointer
1082 to some symbol in the middle of it. Zero out the fields in the
1083 "null symbol" allocated at the end of the array. Note that the
1084 symbol count does *not* include this null symbol, which is why it
1085 is indexed by mcount and not mcount-1. */
1087 SYMBOL_LINKAGE_NAME (&msymbols[mcount]) = NULL;
1088 SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0;
1089 MSYMBOL_TARGET_FLAG_1 (&msymbols[mcount]) = 0;
1090 MSYMBOL_TARGET_FLAG_2 (&msymbols[mcount]) = 0;
1091 MSYMBOL_SIZE (&msymbols[mcount]) = 0;
1092 MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown;
1093 SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown);
1095 /* Attach the minimal symbol table to the specified objfile.
1096 The strings themselves are also located in the objfile_obstack
1099 objfile->minimal_symbol_count = mcount;
1100 objfile->msymbols = msymbols;
1102 /* Try to guess the appropriate C++ ABI by looking at the names
1103 of the minimal symbols in the table. */
1107 for (i = 0; i < mcount; i++)
1109 /* If a symbol's name starts with _Z and was successfully
1110 demangled, then we can assume we've found a GNU v3 symbol.
1111 For now we set the C++ ABI globally; if the user is
1112 mixing ABIs then the user will need to "set cp-abi"
1114 const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]);
1115 if (name[0] == '_' && name[1] == 'Z'
1116 && SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL)
1118 set_cp_abi_as_auto_default ("gnu-v3");
1124 /* Now build the hash tables; we can't do this incrementally
1125 at an earlier point since we weren't finished with the obstack
1126 yet. (And if the msymbol obstack gets moved, all the internal
1127 pointers to other msymbols need to be adjusted.) */
1128 build_minimal_symbol_hash_tables (objfile);
1132 /* Sort all the minimal symbols in OBJFILE. */
1135 msymbols_sort (struct objfile *objfile)
1137 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1138 sizeof (struct minimal_symbol), compare_minimal_symbols);
1139 build_minimal_symbol_hash_tables (objfile);
1142 /* Check if PC is in a shared library trampoline code stub.
1143 Return minimal symbol for the trampoline entry or NULL if PC is not
1144 in a trampoline code stub. */
1146 struct minimal_symbol *
1147 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1149 struct obj_section *section = find_pc_section (pc);
1150 struct minimal_symbol *msymbol;
1152 if (section == NULL)
1154 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1156 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
1161 /* If PC is in a shared library trampoline code stub, return the
1162 address of the `real' function belonging to the stub.
1163 Return 0 if PC is not in a trampoline code stub or if the real
1164 function is not found in the minimal symbol table.
1166 We may fail to find the right function if a function with the
1167 same name is defined in more than one shared library, but this
1168 is considered bad programming style. We could return 0 if we find
1169 a duplicate function in case this matters someday. */
1172 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1174 struct objfile *objfile;
1175 struct minimal_symbol *msymbol;
1176 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1178 if (tsymbol != NULL)
1180 ALL_MSYMBOLS (objfile, msymbol)
1182 if (MSYMBOL_TYPE (msymbol) == mst_text
1183 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1184 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1185 return SYMBOL_VALUE_ADDRESS (msymbol);
1187 /* Also handle minimal symbols pointing to function descriptors. */
1188 if (MSYMBOL_TYPE (msymbol) == mst_data
1189 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1190 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1193 func = gdbarch_convert_from_func_ptr_addr
1194 (get_objfile_arch (objfile),
1195 SYMBOL_VALUE_ADDRESS (msymbol),
1198 /* Ignore data symbols that are not function descriptors. */
1199 if (func != SYMBOL_VALUE_ADDRESS (msymbol))