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 (if non-NULL). Returns a
438 pointer to the minimal symbol if such a symbol is found, or NULL if
439 PC is not in a suitable range. Note that we need to look through
440 ALL the minimal symbol tables before deciding on the symbol that
441 comes closest to the specified PC. This is because objfiles can
442 overlap, for example objfile A has .text at 0x100 and .data at
443 0x40000 and objfile B has .text at 0x234 and .data at 0x40048.
445 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
446 there are text and trampoline symbols at the same address.
447 Otherwise prefer mst_text symbols. */
449 static struct minimal_symbol *
450 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc,
451 struct obj_section *section,
457 struct objfile *objfile;
458 struct minimal_symbol *msymbol;
459 struct minimal_symbol *best_symbol = NULL;
460 struct obj_section *pc_section;
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 /* PC has to be in a known section. This ensures that anything
467 beyond the end of the last segment doesn't appear to be part of
468 the last function in the last segment. */
469 pc_section = find_pc_section (pc);
470 if (pc_section == NULL)
473 /* We can not require the symbol found to be in pc_section, because
474 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
475 symbol - but find_pc_section won't return an absolute section and
476 hence the code below would skip over absolute symbols. We can
477 still take advantage of the call to find_pc_section, though - the
478 object file still must match. In case we have separate debug
479 files, search both the file and its separate debug file. There's
480 no telling which one will have the minimal symbols. */
482 objfile = pc_section->objfile;
483 if (objfile->separate_debug_objfile)
484 objfile = objfile->separate_debug_objfile;
486 for (; objfile != NULL; objfile = objfile->separate_debug_objfile_backlink)
488 /* If this objfile has a minimal symbol table, go search it using
489 a binary search. Note that a minimal symbol table always consists
490 of at least two symbols, a "real" symbol and the terminating
491 "null symbol". If there are no real symbols, then there is no
492 minimal symbol table at all. */
494 if (objfile->minimal_symbol_count > 0)
496 int best_zero_sized = -1;
498 msymbol = objfile->msymbols;
500 hi = objfile->minimal_symbol_count - 1;
502 /* This code assumes that the minimal symbols are sorted by
503 ascending address values. If the pc value is greater than or
504 equal to the first symbol's address, then some symbol in this
505 minimal symbol table is a suitable candidate for being the
506 "best" symbol. This includes the last real symbol, for cases
507 where the pc value is larger than any address in this vector.
509 By iterating until the address associated with the current
510 hi index (the endpoint of the test interval) is less than
511 or equal to the desired pc value, we accomplish two things:
512 (1) the case where the pc value is larger than any minimal
513 symbol address is trivially solved, (2) the address associated
514 with the hi index is always the one we want when the interation
515 terminates. In essence, we are iterating the test interval
516 down until the pc value is pushed out of it from the high end.
518 Warning: this code is trickier than it would appear at first. */
520 /* Should also require that pc is <= end of objfile. FIXME! */
521 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
523 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
525 /* pc is still strictly less than highest address */
526 /* Note "new" will always be >= lo */
528 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
539 /* If we have multiple symbols at the same address, we want
540 hi to point to the last one. That way we can find the
541 right symbol if it has an index greater than hi. */
542 while (hi < objfile->minimal_symbol_count - 1
543 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
544 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
547 /* Skip various undesirable symbols. */
550 /* Skip any absolute symbols. This is apparently
551 what adb and dbx do, and is needed for the CM-5.
552 There are two known possible problems: (1) on
553 ELF, apparently end, edata, etc. are absolute.
554 Not sure ignoring them here is a big deal, but if
555 we want to use them, the fix would go in
556 elfread.c. (2) I think shared library entry
557 points on the NeXT are absolute. If we want
558 special handling for this it probably should be
559 triggered by a special mst_abs_or_lib or some
562 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
568 /* If SECTION was specified, skip any symbol from
571 /* Some types of debug info, such as COFF,
572 don't fill the bfd_section member, so don't
573 throw away symbols on those platforms. */
574 && SYMBOL_OBJ_SECTION (&msymbol[hi]) != NULL
575 && (!matching_obj_sections
576 (SYMBOL_OBJ_SECTION (&msymbol[hi]), section)))
582 /* If we are looking for a trampoline and this is a
583 text symbol, or the other way around, check the
584 preceeding symbol too. If they are otherwise
585 identical prefer that one. */
587 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
588 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
589 && (MSYMBOL_SIZE (&msymbol[hi])
590 == MSYMBOL_SIZE (&msymbol[hi - 1]))
591 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
592 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
593 && (SYMBOL_OBJ_SECTION (&msymbol[hi])
594 == SYMBOL_OBJ_SECTION (&msymbol[hi - 1])))
600 /* If the minimal symbol has a zero size, save it
601 but keep scanning backwards looking for one with
602 a non-zero size. A zero size may mean that the
603 symbol isn't an object or function (e.g. a
604 label), or it may just mean that the size was not
606 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
607 && best_zero_sized == -1)
609 best_zero_sized = hi;
614 /* If we are past the end of the current symbol, try
615 the previous symbol if it has a larger overlapping
616 size. This happens on i686-pc-linux-gnu with glibc;
617 the nocancel variants of system calls are inside
618 the cancellable variants, but both have sizes. */
620 && MSYMBOL_SIZE (&msymbol[hi]) != 0
621 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
622 + MSYMBOL_SIZE (&msymbol[hi]))
623 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
624 + MSYMBOL_SIZE (&msymbol[hi - 1])))
630 /* Otherwise, this symbol must be as good as we're going
635 /* If HI has a zero size, and best_zero_sized is set,
636 then we had two or more zero-sized symbols; prefer
637 the first one we found (which may have a higher
638 address). Also, if we ran off the end, be sure
640 if (best_zero_sized != -1
641 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
642 hi = best_zero_sized;
644 /* If the minimal symbol has a non-zero size, and this
645 PC appears to be outside the symbol's contents, then
646 refuse to use this symbol. If we found a zero-sized
647 symbol with an address greater than this symbol's,
648 use that instead. We assume that if symbols have
649 specified sizes, they do not overlap. */
652 && MSYMBOL_SIZE (&msymbol[hi]) != 0
653 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
654 + MSYMBOL_SIZE (&msymbol[hi])))
656 if (best_zero_sized != -1)
657 hi = best_zero_sized;
659 /* Go on to the next object file. */
663 /* The minimal symbol indexed by hi now is the best one in this
664 objfile's minimal symbol table. See if it is the best one
668 && ((best_symbol == NULL) ||
669 (SYMBOL_VALUE_ADDRESS (best_symbol) <
670 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
672 best_symbol = &msymbol[hi];
677 return (best_symbol);
680 struct minimal_symbol *
681 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
683 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
686 /* Backward compatibility: search through the minimal symbol table
687 for a matching PC (no section given) */
689 struct minimal_symbol *
690 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
692 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
693 force the section but that (well unless you're doing overlay
694 debugging) always returns NULL making the call somewhat useless. */
695 struct obj_section *section = find_pc_section (pc);
698 return lookup_minimal_symbol_by_pc_section (pc, section);
702 /* Return leading symbol character for a BFD. If BFD is NULL,
703 return the leading symbol character from the main objfile. */
705 static int get_symbol_leading_char (bfd *);
708 get_symbol_leading_char (bfd *abfd)
711 return bfd_get_symbol_leading_char (abfd);
712 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
713 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
717 /* Prepare to start collecting minimal symbols. Note that presetting
718 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
719 symbol to allocate the memory for the first bunch. */
722 init_minimal_symbol_collection (void)
726 msym_bunch_index = BUNCH_SIZE;
730 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
731 enum minimal_symbol_type ms_type,
732 struct objfile *objfile)
740 case mst_solib_trampoline:
741 section = SECT_OFF_TEXT (objfile);
745 section = SECT_OFF_DATA (objfile);
749 section = SECT_OFF_BSS (objfile);
755 prim_record_minimal_symbol_and_info (name, address, ms_type,
756 section, NULL, objfile);
759 /* Record a minimal symbol in the msym bunches. Returns the symbol
762 struct minimal_symbol *
763 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
764 enum minimal_symbol_type ms_type,
766 asection *bfd_section,
767 struct objfile *objfile)
769 struct obj_section *obj_section;
770 struct msym_bunch *new;
771 struct minimal_symbol *msymbol;
773 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
774 the minimal symbols, because if there is also another symbol
775 at the same address (e.g. the first function of the file),
776 lookup_minimal_symbol_by_pc would have no way of getting the
778 if (ms_type == mst_file_text && name[0] == 'g'
779 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
780 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
783 /* It's safe to strip the leading char here once, since the name
784 is also stored stripped in the minimal symbol table. */
785 if (name[0] == get_symbol_leading_char (objfile->obfd))
788 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
791 if (msym_bunch_index == BUNCH_SIZE)
793 new = XCALLOC (1, struct msym_bunch);
794 msym_bunch_index = 0;
795 new->next = msym_bunch;
798 msymbol = &msym_bunch->contents[msym_bunch_index];
799 SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown);
800 SYMBOL_LANGUAGE (msymbol) = language_auto;
801 SYMBOL_SET_NAMES (msymbol, (char *)name, strlen (name), objfile);
803 SYMBOL_VALUE_ADDRESS (msymbol) = address;
804 SYMBOL_SECTION (msymbol) = section;
805 SYMBOL_OBJ_SECTION (msymbol) = NULL;
807 /* Find obj_section corresponding to bfd_section. */
809 ALL_OBJFILE_OSECTIONS (objfile, obj_section)
811 if (obj_section->the_bfd_section == bfd_section)
813 SYMBOL_OBJ_SECTION (msymbol) = obj_section;
818 MSYMBOL_TYPE (msymbol) = ms_type;
819 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
820 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
821 MSYMBOL_SIZE (msymbol) = 0;
823 /* The hash pointers must be cleared! If they're not,
824 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
825 msymbol->hash_next = NULL;
826 msymbol->demangled_hash_next = NULL;
830 OBJSTAT (objfile, n_minsyms++);
834 /* Compare two minimal symbols by address and return a signed result based
835 on unsigned comparisons, so that we sort into unsigned numeric order.
836 Within groups with the same address, sort by name. */
839 compare_minimal_symbols (const void *fn1p, const void *fn2p)
841 const struct minimal_symbol *fn1;
842 const struct minimal_symbol *fn2;
844 fn1 = (const struct minimal_symbol *) fn1p;
845 fn2 = (const struct minimal_symbol *) fn2p;
847 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
849 return (-1); /* addr 1 is less than addr 2 */
851 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
853 return (1); /* addr 1 is greater than addr 2 */
856 /* addrs are equal: sort by name */
858 char *name1 = SYMBOL_LINKAGE_NAME (fn1);
859 char *name2 = SYMBOL_LINKAGE_NAME (fn2);
861 if (name1 && name2) /* both have names */
862 return strcmp (name1, name2);
864 return 1; /* fn1 has no name, so it is "less" */
865 else if (name1) /* fn2 has no name, so it is "less" */
868 return (0); /* neither has a name, so they're equal. */
872 /* Discard the currently collected minimal symbols, if any. If we wish
873 to save them for later use, we must have already copied them somewhere
874 else before calling this function.
876 FIXME: We could allocate the minimal symbol bunches on their own
877 obstack and then simply blow the obstack away when we are done with
878 it. Is it worth the extra trouble though? */
881 do_discard_minimal_symbols_cleanup (void *arg)
883 struct msym_bunch *next;
885 while (msym_bunch != NULL)
887 next = msym_bunch->next;
894 make_cleanup_discard_minimal_symbols (void)
896 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
901 /* Compact duplicate entries out of a minimal symbol table by walking
902 through the table and compacting out entries with duplicate addresses
903 and matching names. Return the number of entries remaining.
905 On entry, the table resides between msymbol[0] and msymbol[mcount].
906 On exit, it resides between msymbol[0] and msymbol[result_count].
908 When files contain multiple sources of symbol information, it is
909 possible for the minimal symbol table to contain many duplicate entries.
910 As an example, SVR4 systems use ELF formatted object files, which
911 usually contain at least two different types of symbol tables (a
912 standard ELF one and a smaller dynamic linking table), as well as
913 DWARF debugging information for files compiled with -g.
915 Without compacting, the minimal symbol table for gdb itself contains
916 over a 1000 duplicates, about a third of the total table size. Aside
917 from the potential trap of not noticing that two successive entries
918 identify the same location, this duplication impacts the time required
919 to linearly scan the table, which is done in a number of places. So we
920 just do one linear scan here and toss out the duplicates.
922 Note that we are not concerned here about recovering the space that
923 is potentially freed up, because the strings themselves are allocated
924 on the objfile_obstack, and will get automatically freed when the symbol
925 table is freed. The caller can free up the unused minimal symbols at
926 the end of the compacted region if their allocation strategy allows it.
928 Also note we only go up to the next to last entry within the loop
929 and then copy the last entry explicitly after the loop terminates.
931 Since the different sources of information for each symbol may
932 have different levels of "completeness", we may have duplicates
933 that have one entry with type "mst_unknown" and the other with a
934 known type. So if the one we are leaving alone has type mst_unknown,
935 overwrite its type with the type from the one we are compacting out. */
938 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
939 struct objfile *objfile)
941 struct minimal_symbol *copyfrom;
942 struct minimal_symbol *copyto;
946 copyfrom = copyto = msymbol;
947 while (copyfrom < msymbol + mcount - 1)
949 if (SYMBOL_VALUE_ADDRESS (copyfrom)
950 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
951 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
952 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
954 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
956 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
961 *copyto++ = *copyfrom++;
963 *copyto++ = *copyfrom++;
964 mcount = copyto - msymbol;
969 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
970 after compacting or sorting the table since the entries move around
971 thus causing the internal minimal_symbol pointers to become jumbled. */
974 build_minimal_symbol_hash_tables (struct objfile *objfile)
977 struct minimal_symbol *msym;
979 /* Clear the hash tables. */
980 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
982 objfile->msymbol_hash[i] = 0;
983 objfile->msymbol_demangled_hash[i] = 0;
986 /* Now, (re)insert the actual entries. */
987 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
992 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
994 msym->demangled_hash_next = 0;
995 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
996 add_minsym_to_demangled_hash_table (msym,
997 objfile->msymbol_demangled_hash);
1001 /* Add the minimal symbols in the existing bunches to the objfile's official
1002 minimal symbol table. In most cases there is no minimal symbol table yet
1003 for this objfile, and the existing bunches are used to create one. Once
1004 in a while (for shared libraries for example), we add symbols (e.g. common
1005 symbols) to an existing objfile.
1007 Because of the way minimal symbols are collected, we generally have no way
1008 of knowing what source language applies to any particular minimal symbol.
1009 Specifically, we have no way of knowing if the minimal symbol comes from a
1010 C++ compilation unit or not. So for the sake of supporting cached
1011 demangled C++ names, we have no choice but to try and demangle each new one
1012 that comes in. If the demangling succeeds, then we assume it is a C++
1013 symbol and set the symbol's language and demangled name fields
1014 appropriately. Note that in order to avoid unnecessary demanglings, and
1015 allocating obstack space that subsequently can't be freed for the demangled
1016 names, we mark all newly added symbols with language_auto. After
1017 compaction of the minimal symbols, we go back and scan the entire minimal
1018 symbol table looking for these new symbols. For each new symbol we attempt
1019 to demangle it, and if successful, record it as a language_cplus symbol
1020 and cache the demangled form on the symbol obstack. Symbols which don't
1021 demangle are marked as language_unknown symbols, which inhibits future
1022 attempts to demangle them if we later add more minimal symbols. */
1025 install_minimal_symbols (struct objfile *objfile)
1029 struct msym_bunch *bunch;
1030 struct minimal_symbol *msymbols;
1035 /* Allocate enough space in the obstack, into which we will gather the
1036 bunches of new and existing minimal symbols, sort them, and then
1037 compact out the duplicate entries. Once we have a final table,
1038 we will give back the excess space. */
1040 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1041 obstack_blank (&objfile->objfile_obstack,
1042 alloc_count * sizeof (struct minimal_symbol));
1043 msymbols = (struct minimal_symbol *)
1044 obstack_base (&objfile->objfile_obstack);
1046 /* Copy in the existing minimal symbols, if there are any. */
1048 if (objfile->minimal_symbol_count)
1049 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1050 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1052 /* Walk through the list of minimal symbol bunches, adding each symbol
1053 to the new contiguous array of symbols. Note that we start with the
1054 current, possibly partially filled bunch (thus we use the current
1055 msym_bunch_index for the first bunch we copy over), and thereafter
1056 each bunch is full. */
1058 mcount = objfile->minimal_symbol_count;
1060 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1062 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1063 msymbols[mcount] = bunch->contents[bindex];
1064 msym_bunch_index = BUNCH_SIZE;
1067 /* Sort the minimal symbols by address. */
1069 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1070 compare_minimal_symbols);
1072 /* Compact out any duplicates, and free up whatever space we are
1075 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1077 obstack_blank (&objfile->objfile_obstack,
1078 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1079 msymbols = (struct minimal_symbol *)
1080 obstack_finish (&objfile->objfile_obstack);
1082 /* We also terminate the minimal symbol table with a "null symbol",
1083 which is *not* included in the size of the table. This makes it
1084 easier to find the end of the table when we are handed a pointer
1085 to some symbol in the middle of it. Zero out the fields in the
1086 "null symbol" allocated at the end of the array. Note that the
1087 symbol count does *not* include this null symbol, which is why it
1088 is indexed by mcount and not mcount-1. */
1090 SYMBOL_LINKAGE_NAME (&msymbols[mcount]) = NULL;
1091 SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0;
1092 MSYMBOL_TARGET_FLAG_1 (&msymbols[mcount]) = 0;
1093 MSYMBOL_TARGET_FLAG_2 (&msymbols[mcount]) = 0;
1094 MSYMBOL_SIZE (&msymbols[mcount]) = 0;
1095 MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown;
1096 SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown);
1098 /* Attach the minimal symbol table to the specified objfile.
1099 The strings themselves are also located in the objfile_obstack
1102 objfile->minimal_symbol_count = mcount;
1103 objfile->msymbols = msymbols;
1105 /* Try to guess the appropriate C++ ABI by looking at the names
1106 of the minimal symbols in the table. */
1110 for (i = 0; i < mcount; i++)
1112 /* If a symbol's name starts with _Z and was successfully
1113 demangled, then we can assume we've found a GNU v3 symbol.
1114 For now we set the C++ ABI globally; if the user is
1115 mixing ABIs then the user will need to "set cp-abi"
1117 const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]);
1118 if (name[0] == '_' && name[1] == 'Z'
1119 && SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL)
1121 set_cp_abi_as_auto_default ("gnu-v3");
1127 /* Now build the hash tables; we can't do this incrementally
1128 at an earlier point since we weren't finished with the obstack
1129 yet. (And if the msymbol obstack gets moved, all the internal
1130 pointers to other msymbols need to be adjusted.) */
1131 build_minimal_symbol_hash_tables (objfile);
1135 /* Sort all the minimal symbols in OBJFILE. */
1138 msymbols_sort (struct objfile *objfile)
1140 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1141 sizeof (struct minimal_symbol), compare_minimal_symbols);
1142 build_minimal_symbol_hash_tables (objfile);
1145 /* Check if PC is in a shared library trampoline code stub.
1146 Return minimal symbol for the trampoline entry or NULL if PC is not
1147 in a trampoline code stub. */
1149 struct minimal_symbol *
1150 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1152 struct obj_section *section = find_pc_section (pc);
1153 struct minimal_symbol *msymbol;
1155 if (section == NULL)
1157 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1159 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
1164 /* If PC is in a shared library trampoline code stub, return the
1165 address of the `real' function belonging to the stub.
1166 Return 0 if PC is not in a trampoline code stub or if the real
1167 function is not found in the minimal symbol table.
1169 We may fail to find the right function if a function with the
1170 same name is defined in more than one shared library, but this
1171 is considered bad programming style. We could return 0 if we find
1172 a duplicate function in case this matters someday. */
1175 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1177 struct objfile *objfile;
1178 struct minimal_symbol *msymbol;
1179 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1181 if (tsymbol != NULL)
1183 ALL_MSYMBOLS (objfile, msymbol)
1185 if (MSYMBOL_TYPE (msymbol) == mst_text
1186 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1187 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1188 return SYMBOL_VALUE_ADDRESS (msymbol);
1190 /* Also handle minimal symbols pointing to function descriptors. */
1191 if (MSYMBOL_TYPE (msymbol) == mst_data
1192 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1193 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1196 func = gdbarch_convert_from_func_ptr_addr
1197 (get_objfile_arch (objfile),
1198 SYMBOL_VALUE_ADDRESS (msymbol),
1201 /* Ignore data symbols that are not function descriptors. */
1202 if (func != SYMBOL_VALUE_ADDRESS (msymbol))