1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2004, 2007-2012 Free Software Foundation, Inc.
3 Contributed by Cygnus Support, using pieces from other GDB modules.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 /* This file contains support routines for creating, manipulating, and
22 destroying minimal symbol tables.
24 Minimal symbol tables are used to hold some very basic information about
25 all defined global symbols (text, data, bss, abs, etc). The only two
26 required pieces of information are the symbol's name and the address
27 associated with that symbol.
29 In many cases, even if a file was compiled with no special options for
30 debugging at all, as long as was not stripped it will contain sufficient
31 information to build useful minimal symbol tables using this structure.
33 Even when a file contains enough debugging information to build a full
34 symbol table, these minimal symbols are still useful for quickly mapping
35 between names and addresses, and vice versa. They are also sometimes used
36 to figure out what full symbol table entries need to be read in. */
41 #include "gdb_string.h"
44 #include "filenames.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;
86 while (*string && *string != '(')
88 while (isspace (*string))
90 if (*string && *string != '(')
92 hash = SYMBOL_HASH_NEXT (hash, *string);
99 /* Compute a hash code for a string. */
102 msymbol_hash (const char *string)
104 unsigned int hash = 0;
106 for (; *string; ++string)
107 hash = SYMBOL_HASH_NEXT (hash, *string);
111 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
113 add_minsym_to_hash_table (struct minimal_symbol *sym,
114 struct minimal_symbol **table)
116 if (sym->hash_next == NULL)
119 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
121 sym->hash_next = table[hash];
126 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
129 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
130 struct minimal_symbol **table)
132 if (sym->demangled_hash_next == NULL)
134 unsigned int hash = msymbol_hash_iw (SYMBOL_SEARCH_NAME (sym))
135 % MINIMAL_SYMBOL_HASH_SIZE;
137 sym->demangled_hash_next = table[hash];
143 /* Return OBJFILE where minimal symbol SYM is defined. */
145 msymbol_objfile (struct minimal_symbol *sym)
147 struct objfile *objf;
148 struct minimal_symbol *tsym;
151 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
153 for (objf = object_files; objf; objf = objf->next)
154 for (tsym = objf->msymbol_hash[hash]; tsym; tsym = tsym->hash_next)
158 /* We should always be able to find the objfile ... */
159 internal_error (__FILE__, __LINE__, _("failed internal consistency check"));
163 /* Look through all the current minimal symbol tables and find the
164 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
165 the search to that objfile. If SFILE is non-NULL, the only file-scope
166 symbols considered will be from that source file (global symbols are
167 still preferred). Returns a pointer to the minimal symbol that
168 matches, or NULL if no match is found.
170 Note: One instance where there may be duplicate minimal symbols with
171 the same name is when the symbol tables for a shared library and the
172 symbol tables for an executable contain global symbols with the same
173 names (the dynamic linker deals with the duplication).
175 It's also possible to have minimal symbols with different mangled
176 names, but identical demangled names. For example, the GNU C++ v3
177 ABI requires the generation of two (or perhaps three) copies of
178 constructor functions --- "in-charge", "not-in-charge", and
179 "allocate" copies; destructors may be duplicated as well.
180 Obviously, there must be distinct mangled names for each of these,
181 but the demangled names are all the same: S::S or S::~S. */
183 struct minimal_symbol *
184 lookup_minimal_symbol (const char *name, const char *sfile,
185 struct objfile *objf)
187 struct objfile *objfile;
188 struct minimal_symbol *msymbol;
189 struct minimal_symbol *found_symbol = NULL;
190 struct minimal_symbol *found_file_symbol = NULL;
191 struct minimal_symbol *trampoline_symbol = NULL;
193 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
194 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
196 int needtofreename = 0;
197 const char *modified_name;
200 sfile = lbasename (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);
210 modified_name = cname;
215 for (objfile = object_files;
216 objfile != NULL && found_symbol == NULL;
217 objfile = objfile->next)
219 if (objf == NULL || objf == objfile
220 || objf == objfile->separate_debug_objfile_backlink)
222 /* Do two passes: the first over the ordinary hash table,
223 and the second over the demangled hash table. */
226 for (pass = 1; pass <= 2 && found_symbol == NULL; pass++)
228 /* Select hash list according to pass. */
230 msymbol = objfile->msymbol_hash[hash];
232 msymbol = objfile->msymbol_demangled_hash[dem_hash];
234 while (msymbol != NULL && found_symbol == NULL)
240 int (*cmp) (const char *, const char *);
242 cmp = (case_sensitivity == case_sensitive_on
243 ? strcmp : strcasecmp);
244 match = cmp (SYMBOL_LINKAGE_NAME (msymbol),
249 /* The function respects CASE_SENSITIVITY. */
250 match = SYMBOL_MATCHES_SEARCH_NAME (msymbol,
256 switch (MSYMBOL_TYPE (msymbol))
262 || filename_cmp (msymbol->filename, sfile) == 0)
263 found_file_symbol = msymbol;
266 case mst_solib_trampoline:
268 /* If a trampoline symbol is found, we prefer to
269 keep looking for the *real* symbol. If the
270 actual symbol is not found, then we'll use the
272 if (trampoline_symbol == NULL)
273 trampoline_symbol = msymbol;
278 found_symbol = msymbol;
283 /* Find the next symbol on the hash chain. */
285 msymbol = msymbol->hash_next;
287 msymbol = msymbol->demangled_hash_next;
294 xfree ((void *) modified_name);
296 /* External symbols are best. */
300 /* File-local symbols are next best. */
301 if (found_file_symbol)
302 return found_file_symbol;
304 /* Symbols for shared library trampolines are next best. */
305 if (trampoline_symbol)
306 return trampoline_symbol;
311 /* Iterate over all the minimal symbols in the objfile OBJF which
312 match NAME. Both the ordinary and demangled names of each symbol
313 are considered. The caller is responsible for canonicalizing NAME,
314 should that need to be done.
316 For each matching symbol, CALLBACK is called with the symbol and
317 USER_DATA as arguments. */
320 iterate_over_minimal_symbols (struct objfile *objf, const char *name,
321 void (*callback) (struct minimal_symbol *,
326 struct minimal_symbol *iter;
327 int (*cmp) (const char *, const char *);
329 /* The first pass is over the ordinary hash table. */
330 hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
331 iter = objf->msymbol_hash[hash];
332 cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);
335 if (cmp (SYMBOL_LINKAGE_NAME (iter), name) == 0)
336 (*callback) (iter, user_data);
337 iter = iter->hash_next;
340 /* The second pass is over the demangled table. */
341 hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
342 iter = objf->msymbol_demangled_hash[hash];
345 if (SYMBOL_MATCHES_SEARCH_NAME (iter, name))
346 (*callback) (iter, user_data);
347 iter = iter->demangled_hash_next;
351 /* Look through all the current minimal symbol tables and find the
352 first minimal symbol that matches NAME and has text type. If OBJF
353 is non-NULL, limit the search to that objfile. Returns a pointer
354 to the minimal symbol that matches, or NULL if no match is found.
356 This function only searches the mangled (linkage) names. */
358 struct minimal_symbol *
359 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
361 struct objfile *objfile;
362 struct minimal_symbol *msymbol;
363 struct minimal_symbol *found_symbol = NULL;
364 struct minimal_symbol *found_file_symbol = NULL;
366 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
368 for (objfile = object_files;
369 objfile != NULL && found_symbol == NULL;
370 objfile = objfile->next)
372 if (objf == NULL || objf == objfile
373 || objf == objfile->separate_debug_objfile_backlink)
375 for (msymbol = objfile->msymbol_hash[hash];
376 msymbol != NULL && found_symbol == NULL;
377 msymbol = msymbol->hash_next)
379 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
380 (MSYMBOL_TYPE (msymbol) == mst_text
381 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
382 || MSYMBOL_TYPE (msymbol) == mst_file_text))
384 switch (MSYMBOL_TYPE (msymbol))
387 found_file_symbol = msymbol;
390 found_symbol = msymbol;
397 /* External symbols are best. */
401 /* File-local symbols are next best. */
402 if (found_file_symbol)
403 return found_file_symbol;
408 /* Look through all the current minimal symbol tables and find the
409 first minimal symbol that matches NAME and PC. If OBJF is non-NULL,
410 limit the search to that objfile. Returns a pointer to the minimal
411 symbol that matches, or NULL if no match is found. */
413 struct minimal_symbol *
414 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
415 struct objfile *objf)
417 struct objfile *objfile;
418 struct minimal_symbol *msymbol;
420 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
422 for (objfile = object_files;
424 objfile = objfile->next)
426 if (objf == NULL || objf == objfile
427 || objf == objfile->separate_debug_objfile_backlink)
429 for (msymbol = objfile->msymbol_hash[hash];
431 msymbol = msymbol->hash_next)
433 if (SYMBOL_VALUE_ADDRESS (msymbol) == pc
434 && strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0)
443 /* Look through all the current minimal symbol tables and find the
444 first minimal symbol that matches NAME and is a solib trampoline.
445 If OBJF is non-NULL, limit the search to that objfile. Returns a
446 pointer to the minimal symbol that matches, or NULL if no match is
449 This function only searches the mangled (linkage) names. */
451 struct minimal_symbol *
452 lookup_minimal_symbol_solib_trampoline (const char *name,
453 struct objfile *objf)
455 struct objfile *objfile;
456 struct minimal_symbol *msymbol;
457 struct minimal_symbol *found_symbol = NULL;
459 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
461 for (objfile = object_files;
462 objfile != NULL && found_symbol == NULL;
463 objfile = objfile->next)
465 if (objf == NULL || objf == objfile
466 || objf == objfile->separate_debug_objfile_backlink)
468 for (msymbol = objfile->msymbol_hash[hash];
469 msymbol != NULL && found_symbol == NULL;
470 msymbol = msymbol->hash_next)
472 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
473 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
482 /* Search through the minimal symbol table for each objfile and find
483 the symbol whose address is the largest address that is still less
484 than or equal to PC, and matches SECTION (which is not NULL).
485 Returns a pointer to the minimal symbol if such a symbol is found,
486 or NULL if PC is not in a suitable range.
487 Note that we need to look through ALL the minimal symbol tables
488 before deciding on the symbol that comes closest to the specified PC.
489 This is because objfiles can overlap, for example objfile A has .text
490 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
493 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
494 there are text and trampoline symbols at the same address.
495 Otherwise prefer mst_text symbols. */
497 static struct minimal_symbol *
498 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc,
499 struct obj_section *section,
505 struct objfile *objfile;
506 struct minimal_symbol *msymbol;
507 struct minimal_symbol *best_symbol = NULL;
508 enum minimal_symbol_type want_type, other_type;
510 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
511 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
513 /* We can not require the symbol found to be in section, because
514 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
515 symbol - but find_pc_section won't return an absolute section and
516 hence the code below would skip over absolute symbols. We can
517 still take advantage of the call to find_pc_section, though - the
518 object file still must match. In case we have separate debug
519 files, search both the file and its separate debug file. There's
520 no telling which one will have the minimal symbols. */
522 gdb_assert (section != NULL);
524 for (objfile = section->objfile;
526 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
528 /* If this objfile has a minimal symbol table, go search it using
529 a binary search. Note that a minimal symbol table always consists
530 of at least two symbols, a "real" symbol and the terminating
531 "null symbol". If there are no real symbols, then there is no
532 minimal symbol table at all. */
534 if (objfile->minimal_symbol_count > 0)
536 int best_zero_sized = -1;
538 msymbol = objfile->msymbols;
540 hi = objfile->minimal_symbol_count - 1;
542 /* This code assumes that the minimal symbols are sorted by
543 ascending address values. If the pc value is greater than or
544 equal to the first symbol's address, then some symbol in this
545 minimal symbol table is a suitable candidate for being the
546 "best" symbol. This includes the last real symbol, for cases
547 where the pc value is larger than any address in this vector.
549 By iterating until the address associated with the current
550 hi index (the endpoint of the test interval) is less than
551 or equal to the desired pc value, we accomplish two things:
552 (1) the case where the pc value is larger than any minimal
553 symbol address is trivially solved, (2) the address associated
554 with the hi index is always the one we want when the interation
555 terminates. In essence, we are iterating the test interval
556 down until the pc value is pushed out of it from the high end.
558 Warning: this code is trickier than it would appear at first. */
560 /* Should also require that pc is <= end of objfile. FIXME! */
561 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
563 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
565 /* pc is still strictly less than highest address. */
566 /* Note "new" will always be >= lo. */
568 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
579 /* If we have multiple symbols at the same address, we want
580 hi to point to the last one. That way we can find the
581 right symbol if it has an index greater than hi. */
582 while (hi < objfile->minimal_symbol_count - 1
583 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
584 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
587 /* Skip various undesirable symbols. */
590 /* Skip any absolute symbols. This is apparently
591 what adb and dbx do, and is needed for the CM-5.
592 There are two known possible problems: (1) on
593 ELF, apparently end, edata, etc. are absolute.
594 Not sure ignoring them here is a big deal, but if
595 we want to use them, the fix would go in
596 elfread.c. (2) I think shared library entry
597 points on the NeXT are absolute. If we want
598 special handling for this it probably should be
599 triggered by a special mst_abs_or_lib or some
602 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
608 /* If SECTION was specified, skip any symbol from
611 /* Some types of debug info, such as COFF,
612 don't fill the bfd_section member, so don't
613 throw away symbols on those platforms. */
614 && SYMBOL_OBJ_SECTION (&msymbol[hi]) != NULL
615 && (!matching_obj_sections
616 (SYMBOL_OBJ_SECTION (&msymbol[hi]), section)))
622 /* If we are looking for a trampoline and this is a
623 text symbol, or the other way around, check the
624 preceding symbol too. If they are otherwise
625 identical prefer that one. */
627 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
628 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
629 && (MSYMBOL_SIZE (&msymbol[hi])
630 == MSYMBOL_SIZE (&msymbol[hi - 1]))
631 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
632 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
633 && (SYMBOL_OBJ_SECTION (&msymbol[hi])
634 == SYMBOL_OBJ_SECTION (&msymbol[hi - 1])))
640 /* If the minimal symbol has a zero size, save it
641 but keep scanning backwards looking for one with
642 a non-zero size. A zero size may mean that the
643 symbol isn't an object or function (e.g. a
644 label), or it may just mean that the size was not
646 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
647 && best_zero_sized == -1)
649 best_zero_sized = hi;
654 /* If we are past the end of the current symbol, try
655 the previous symbol if it has a larger overlapping
656 size. This happens on i686-pc-linux-gnu with glibc;
657 the nocancel variants of system calls are inside
658 the cancellable variants, but both have sizes. */
660 && MSYMBOL_SIZE (&msymbol[hi]) != 0
661 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
662 + MSYMBOL_SIZE (&msymbol[hi]))
663 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
664 + MSYMBOL_SIZE (&msymbol[hi - 1])))
670 /* Otherwise, this symbol must be as good as we're going
675 /* If HI has a zero size, and best_zero_sized is set,
676 then we had two or more zero-sized symbols; prefer
677 the first one we found (which may have a higher
678 address). Also, if we ran off the end, be sure
680 if (best_zero_sized != -1
681 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
682 hi = best_zero_sized;
684 /* If the minimal symbol has a non-zero size, and this
685 PC appears to be outside the symbol's contents, then
686 refuse to use this symbol. If we found a zero-sized
687 symbol with an address greater than this symbol's,
688 use that instead. We assume that if symbols have
689 specified sizes, they do not overlap. */
692 && MSYMBOL_SIZE (&msymbol[hi]) != 0
693 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
694 + MSYMBOL_SIZE (&msymbol[hi])))
696 if (best_zero_sized != -1)
697 hi = best_zero_sized;
699 /* Go on to the next object file. */
703 /* The minimal symbol indexed by hi now is the best one in this
704 objfile's minimal symbol table. See if it is the best one
708 && ((best_symbol == NULL) ||
709 (SYMBOL_VALUE_ADDRESS (best_symbol) <
710 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
712 best_symbol = &msymbol[hi];
717 return (best_symbol);
720 struct minimal_symbol *
721 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
725 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
726 force the section but that (well unless you're doing overlay
727 debugging) always returns NULL making the call somewhat useless. */
728 section = find_pc_section (pc);
732 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
735 /* Backward compatibility: search through the minimal symbol table
736 for a matching PC (no section given). */
738 struct minimal_symbol *
739 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
741 return lookup_minimal_symbol_by_pc_section (pc, NULL);
744 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
747 in_gnu_ifunc_stub (CORE_ADDR pc)
749 struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (pc);
751 return msymbol && MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc;
754 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
757 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
759 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
760 "the ELF support compiled in."),
761 paddress (gdbarch, pc));
764 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
767 stub_gnu_ifunc_resolve_name (const char *function_name,
768 CORE_ADDR *function_address_p)
770 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
771 "the ELF support compiled in."),
775 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
778 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
780 internal_error (__FILE__, __LINE__,
781 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
784 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
787 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
789 internal_error (__FILE__, __LINE__,
790 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
793 /* See elf_gnu_ifunc_fns for its real implementation. */
795 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
797 stub_gnu_ifunc_resolve_addr,
798 stub_gnu_ifunc_resolve_name,
799 stub_gnu_ifunc_resolver_stop,
800 stub_gnu_ifunc_resolver_return_stop,
803 /* A placeholder for &elf_gnu_ifunc_fns. */
805 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
807 /* Find the minimal symbol named NAME, and return both the minsym
808 struct and its objfile. This only checks the linkage name. Sets
809 *OBJFILE_P and returns the minimal symbol, if it is found. If it
810 is not found, returns NULL. */
812 struct minimal_symbol *
813 lookup_minimal_symbol_and_objfile (const char *name,
814 struct objfile **objfile_p)
816 struct objfile *objfile;
817 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
819 ALL_OBJFILES (objfile)
821 struct minimal_symbol *msym;
823 for (msym = objfile->msymbol_hash[hash];
825 msym = msym->hash_next)
827 if (strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
829 *objfile_p = objfile;
839 /* Return leading symbol character for a BFD. If BFD is NULL,
840 return the leading symbol character from the main objfile. */
842 static int get_symbol_leading_char (bfd *);
845 get_symbol_leading_char (bfd *abfd)
848 return bfd_get_symbol_leading_char (abfd);
849 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
850 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
854 /* Prepare to start collecting minimal symbols. Note that presetting
855 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
856 symbol to allocate the memory for the first bunch. */
859 init_minimal_symbol_collection (void)
863 msym_bunch_index = BUNCH_SIZE;
867 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
868 enum minimal_symbol_type ms_type,
869 struct objfile *objfile)
876 case mst_text_gnu_ifunc:
878 case mst_solib_trampoline:
879 section = SECT_OFF_TEXT (objfile);
883 section = SECT_OFF_DATA (objfile);
887 section = SECT_OFF_BSS (objfile);
893 prim_record_minimal_symbol_and_info (name, address, ms_type,
894 section, NULL, objfile);
897 /* Record a minimal symbol in the msym bunches. Returns the symbol
900 struct minimal_symbol *
901 prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
903 enum minimal_symbol_type ms_type,
905 asection *bfd_section,
906 struct objfile *objfile)
908 struct obj_section *obj_section;
909 struct msym_bunch *new;
910 struct minimal_symbol *msymbol;
912 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
913 the minimal symbols, because if there is also another symbol
914 at the same address (e.g. the first function of the file),
915 lookup_minimal_symbol_by_pc would have no way of getting the
917 if (ms_type == mst_file_text && name[0] == 'g'
918 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
919 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
922 /* It's safe to strip the leading char here once, since the name
923 is also stored stripped in the minimal symbol table. */
924 if (name[0] == get_symbol_leading_char (objfile->obfd))
930 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
933 if (msym_bunch_index == BUNCH_SIZE)
935 new = XCALLOC (1, struct msym_bunch);
936 msym_bunch_index = 0;
937 new->next = msym_bunch;
940 msymbol = &msym_bunch->contents[msym_bunch_index];
941 SYMBOL_SET_LANGUAGE (msymbol, language_auto);
942 SYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, objfile);
944 SYMBOL_VALUE_ADDRESS (msymbol) = address;
945 SYMBOL_SECTION (msymbol) = section;
946 SYMBOL_OBJ_SECTION (msymbol) = NULL;
948 /* Find obj_section corresponding to bfd_section. */
950 ALL_OBJFILE_OSECTIONS (objfile, obj_section)
952 if (obj_section->the_bfd_section == bfd_section)
954 SYMBOL_OBJ_SECTION (msymbol) = obj_section;
959 MSYMBOL_TYPE (msymbol) = ms_type;
960 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
961 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
962 MSYMBOL_SIZE (msymbol) = 0;
964 /* The hash pointers must be cleared! If they're not,
965 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
966 msymbol->hash_next = NULL;
967 msymbol->demangled_hash_next = NULL;
971 OBJSTAT (objfile, n_minsyms++);
975 /* Record a minimal symbol in the msym bunches. Returns the symbol
978 struct minimal_symbol *
979 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
980 enum minimal_symbol_type ms_type,
982 asection *bfd_section,
983 struct objfile *objfile)
985 return prim_record_minimal_symbol_full (name, strlen (name), 1,
986 address, ms_type, section,
987 bfd_section, objfile);
990 /* Compare two minimal symbols by address and return a signed result based
991 on unsigned comparisons, so that we sort into unsigned numeric order.
992 Within groups with the same address, sort by name. */
995 compare_minimal_symbols (const void *fn1p, const void *fn2p)
997 const struct minimal_symbol *fn1;
998 const struct minimal_symbol *fn2;
1000 fn1 = (const struct minimal_symbol *) fn1p;
1001 fn2 = (const struct minimal_symbol *) fn2p;
1003 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
1005 return (-1); /* addr 1 is less than addr 2. */
1007 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
1009 return (1); /* addr 1 is greater than addr 2. */
1012 /* addrs are equal: sort by name */
1014 char *name1 = SYMBOL_LINKAGE_NAME (fn1);
1015 char *name2 = SYMBOL_LINKAGE_NAME (fn2);
1017 if (name1 && name2) /* both have names */
1018 return strcmp (name1, name2);
1020 return 1; /* fn1 has no name, so it is "less". */
1021 else if (name1) /* fn2 has no name, so it is "less". */
1024 return (0); /* Neither has a name, so they're equal. */
1028 /* Discard the currently collected minimal symbols, if any. If we wish
1029 to save them for later use, we must have already copied them somewhere
1030 else before calling this function.
1032 FIXME: We could allocate the minimal symbol bunches on their own
1033 obstack and then simply blow the obstack away when we are done with
1034 it. Is it worth the extra trouble though? */
1037 do_discard_minimal_symbols_cleanup (void *arg)
1039 struct msym_bunch *next;
1041 while (msym_bunch != NULL)
1043 next = msym_bunch->next;
1050 make_cleanup_discard_minimal_symbols (void)
1052 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
1057 /* Compact duplicate entries out of a minimal symbol table by walking
1058 through the table and compacting out entries with duplicate addresses
1059 and matching names. Return the number of entries remaining.
1061 On entry, the table resides between msymbol[0] and msymbol[mcount].
1062 On exit, it resides between msymbol[0] and msymbol[result_count].
1064 When files contain multiple sources of symbol information, it is
1065 possible for the minimal symbol table to contain many duplicate entries.
1066 As an example, SVR4 systems use ELF formatted object files, which
1067 usually contain at least two different types of symbol tables (a
1068 standard ELF one and a smaller dynamic linking table), as well as
1069 DWARF debugging information for files compiled with -g.
1071 Without compacting, the minimal symbol table for gdb itself contains
1072 over a 1000 duplicates, about a third of the total table size. Aside
1073 from the potential trap of not noticing that two successive entries
1074 identify the same location, this duplication impacts the time required
1075 to linearly scan the table, which is done in a number of places. So we
1076 just do one linear scan here and toss out the duplicates.
1078 Note that we are not concerned here about recovering the space that
1079 is potentially freed up, because the strings themselves are allocated
1080 on the objfile_obstack, and will get automatically freed when the symbol
1081 table is freed. The caller can free up the unused minimal symbols at
1082 the end of the compacted region if their allocation strategy allows it.
1084 Also note we only go up to the next to last entry within the loop
1085 and then copy the last entry explicitly after the loop terminates.
1087 Since the different sources of information for each symbol may
1088 have different levels of "completeness", we may have duplicates
1089 that have one entry with type "mst_unknown" and the other with a
1090 known type. So if the one we are leaving alone has type mst_unknown,
1091 overwrite its type with the type from the one we are compacting out. */
1094 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1095 struct objfile *objfile)
1097 struct minimal_symbol *copyfrom;
1098 struct minimal_symbol *copyto;
1102 copyfrom = copyto = msymbol;
1103 while (copyfrom < msymbol + mcount - 1)
1105 if (SYMBOL_VALUE_ADDRESS (copyfrom)
1106 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
1107 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
1108 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1110 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1112 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1117 *copyto++ = *copyfrom++;
1119 *copyto++ = *copyfrom++;
1120 mcount = copyto - msymbol;
1125 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1126 after compacting or sorting the table since the entries move around
1127 thus causing the internal minimal_symbol pointers to become jumbled. */
1130 build_minimal_symbol_hash_tables (struct objfile *objfile)
1133 struct minimal_symbol *msym;
1135 /* Clear the hash tables. */
1136 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1138 objfile->msymbol_hash[i] = 0;
1139 objfile->msymbol_demangled_hash[i] = 0;
1142 /* Now, (re)insert the actual entries. */
1143 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
1147 msym->hash_next = 0;
1148 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
1150 msym->demangled_hash_next = 0;
1151 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
1152 add_minsym_to_demangled_hash_table (msym,
1153 objfile->msymbol_demangled_hash);
1157 /* Add the minimal symbols in the existing bunches to the objfile's official
1158 minimal symbol table. In most cases there is no minimal symbol table yet
1159 for this objfile, and the existing bunches are used to create one. Once
1160 in a while (for shared libraries for example), we add symbols (e.g. common
1161 symbols) to an existing objfile.
1163 Because of the way minimal symbols are collected, we generally have no way
1164 of knowing what source language applies to any particular minimal symbol.
1165 Specifically, we have no way of knowing if the minimal symbol comes from a
1166 C++ compilation unit or not. So for the sake of supporting cached
1167 demangled C++ names, we have no choice but to try and demangle each new one
1168 that comes in. If the demangling succeeds, then we assume it is a C++
1169 symbol and set the symbol's language and demangled name fields
1170 appropriately. Note that in order to avoid unnecessary demanglings, and
1171 allocating obstack space that subsequently can't be freed for the demangled
1172 names, we mark all newly added symbols with language_auto. After
1173 compaction of the minimal symbols, we go back and scan the entire minimal
1174 symbol table looking for these new symbols. For each new symbol we attempt
1175 to demangle it, and if successful, record it as a language_cplus symbol
1176 and cache the demangled form on the symbol obstack. Symbols which don't
1177 demangle are marked as language_unknown symbols, which inhibits future
1178 attempts to demangle them if we later add more minimal symbols. */
1181 install_minimal_symbols (struct objfile *objfile)
1185 struct msym_bunch *bunch;
1186 struct minimal_symbol *msymbols;
1191 /* Allocate enough space in the obstack, into which we will gather the
1192 bunches of new and existing minimal symbols, sort them, and then
1193 compact out the duplicate entries. Once we have a final table,
1194 we will give back the excess space. */
1196 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1197 obstack_blank (&objfile->objfile_obstack,
1198 alloc_count * sizeof (struct minimal_symbol));
1199 msymbols = (struct minimal_symbol *)
1200 obstack_base (&objfile->objfile_obstack);
1202 /* Copy in the existing minimal symbols, if there are any. */
1204 if (objfile->minimal_symbol_count)
1205 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1206 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1208 /* Walk through the list of minimal symbol bunches, adding each symbol
1209 to the new contiguous array of symbols. Note that we start with the
1210 current, possibly partially filled bunch (thus we use the current
1211 msym_bunch_index for the first bunch we copy over), and thereafter
1212 each bunch is full. */
1214 mcount = objfile->minimal_symbol_count;
1216 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1218 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1219 msymbols[mcount] = bunch->contents[bindex];
1220 msym_bunch_index = BUNCH_SIZE;
1223 /* Sort the minimal symbols by address. */
1225 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1226 compare_minimal_symbols);
1228 /* Compact out any duplicates, and free up whatever space we are
1231 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1233 obstack_blank (&objfile->objfile_obstack,
1234 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1235 msymbols = (struct minimal_symbol *)
1236 obstack_finish (&objfile->objfile_obstack);
1238 /* We also terminate the minimal symbol table with a "null symbol",
1239 which is *not* included in the size of the table. This makes it
1240 easier to find the end of the table when we are handed a pointer
1241 to some symbol in the middle of it. Zero out the fields in the
1242 "null symbol" allocated at the end of the array. Note that the
1243 symbol count does *not* include this null symbol, which is why it
1244 is indexed by mcount and not mcount-1. */
1246 SYMBOL_LINKAGE_NAME (&msymbols[mcount]) = NULL;
1247 SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0;
1248 MSYMBOL_TARGET_FLAG_1 (&msymbols[mcount]) = 0;
1249 MSYMBOL_TARGET_FLAG_2 (&msymbols[mcount]) = 0;
1250 MSYMBOL_SIZE (&msymbols[mcount]) = 0;
1251 MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown;
1252 SYMBOL_SET_LANGUAGE (&msymbols[mcount], language_unknown);
1254 /* Attach the minimal symbol table to the specified objfile.
1255 The strings themselves are also located in the objfile_obstack
1258 objfile->minimal_symbol_count = mcount;
1259 objfile->msymbols = msymbols;
1261 /* Try to guess the appropriate C++ ABI by looking at the names
1262 of the minimal symbols in the table. */
1266 for (i = 0; i < mcount; i++)
1268 /* If a symbol's name starts with _Z and was successfully
1269 demangled, then we can assume we've found a GNU v3 symbol.
1270 For now we set the C++ ABI globally; if the user is
1271 mixing ABIs then the user will need to "set cp-abi"
1273 const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]);
1275 if (name[0] == '_' && name[1] == 'Z'
1276 && SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL)
1278 set_cp_abi_as_auto_default ("gnu-v3");
1284 /* Now build the hash tables; we can't do this incrementally
1285 at an earlier point since we weren't finished with the obstack
1286 yet. (And if the msymbol obstack gets moved, all the internal
1287 pointers to other msymbols need to be adjusted.) */
1288 build_minimal_symbol_hash_tables (objfile);
1292 /* Sort all the minimal symbols in OBJFILE. */
1295 msymbols_sort (struct objfile *objfile)
1297 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1298 sizeof (struct minimal_symbol), compare_minimal_symbols);
1299 build_minimal_symbol_hash_tables (objfile);
1302 /* Check if PC is in a shared library trampoline code stub.
1303 Return minimal symbol for the trampoline entry or NULL if PC is not
1304 in a trampoline code stub. */
1306 struct minimal_symbol *
1307 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1309 struct obj_section *section = find_pc_section (pc);
1310 struct minimal_symbol *msymbol;
1312 if (section == NULL)
1314 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1316 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
1321 /* If PC is in a shared library trampoline code stub, return the
1322 address of the `real' function belonging to the stub.
1323 Return 0 if PC is not in a trampoline code stub or if the real
1324 function is not found in the minimal symbol table.
1326 We may fail to find the right function if a function with the
1327 same name is defined in more than one shared library, but this
1328 is considered bad programming style. We could return 0 if we find
1329 a duplicate function in case this matters someday. */
1332 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1334 struct objfile *objfile;
1335 struct minimal_symbol *msymbol;
1336 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1338 if (tsymbol != NULL)
1340 ALL_MSYMBOLS (objfile, msymbol)
1342 if ((MSYMBOL_TYPE (msymbol) == mst_text
1343 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1344 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1345 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1346 return SYMBOL_VALUE_ADDRESS (msymbol);
1348 /* Also handle minimal symbols pointing to function descriptors. */
1349 if (MSYMBOL_TYPE (msymbol) == mst_data
1350 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1351 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1355 func = gdbarch_convert_from_func_ptr_addr
1356 (get_objfile_arch (objfile),
1357 SYMBOL_VALUE_ADDRESS (msymbol),
1360 /* Ignore data symbols that are not function descriptors. */
1361 if (func != SYMBOL_VALUE_ADDRESS (msymbol))