1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2014 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. */
43 #include "filenames.h"
50 #include "cp-support.h"
52 #include "cli/cli-utils.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
56 per-BFD storage obstack. */
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;
82 msymbol_hash_iw (const char *string)
84 unsigned int hash = 0;
86 while (*string && *string != '(')
88 string = skip_spaces_const (string);
89 if (*string && *string != '(')
91 hash = SYMBOL_HASH_NEXT (hash, *string);
101 msymbol_hash (const char *string)
103 unsigned int hash = 0;
105 for (; *string; ++string)
106 hash = SYMBOL_HASH_NEXT (hash, *string);
110 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
112 add_minsym_to_hash_table (struct minimal_symbol *sym,
113 struct minimal_symbol **table)
115 if (sym->hash_next == NULL)
118 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
120 sym->hash_next = table[hash];
125 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
128 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
129 struct minimal_symbol **table)
131 if (sym->demangled_hash_next == NULL)
133 unsigned int hash = msymbol_hash_iw (MSYMBOL_SEARCH_NAME (sym))
134 % MINIMAL_SYMBOL_HASH_SIZE;
136 sym->demangled_hash_next = table[hash];
141 /* Look through all the current minimal symbol tables and find the
142 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
143 the search to that objfile. If SFILE is non-NULL, the only file-scope
144 symbols considered will be from that source file (global symbols are
145 still preferred). Returns a pointer to the minimal symbol that
146 matches, or NULL if no match is found.
148 Note: One instance where there may be duplicate minimal symbols with
149 the same name is when the symbol tables for a shared library and the
150 symbol tables for an executable contain global symbols with the same
151 names (the dynamic linker deals with the duplication).
153 It's also possible to have minimal symbols with different mangled
154 names, but identical demangled names. For example, the GNU C++ v3
155 ABI requires the generation of two (or perhaps three) copies of
156 constructor functions --- "in-charge", "not-in-charge", and
157 "allocate" copies; destructors may be duplicated as well.
158 Obviously, there must be distinct mangled names for each of these,
159 but the demangled names are all the same: S::S or S::~S. */
161 struct bound_minimal_symbol
162 lookup_minimal_symbol (const char *name, const char *sfile,
163 struct objfile *objf)
165 struct objfile *objfile;
166 struct bound_minimal_symbol found_symbol = { NULL, NULL };
167 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
168 struct bound_minimal_symbol trampoline_symbol = { NULL, NULL };
170 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
171 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
173 int needtofreename = 0;
174 const char *modified_name;
177 sfile = lbasename (sfile);
179 /* For C++, canonicalize the input name. */
180 modified_name = name;
181 if (current_language->la_language == language_cplus)
183 char *cname = cp_canonicalize_string (name);
187 modified_name = cname;
192 for (objfile = object_files;
193 objfile != NULL && found_symbol.minsym == NULL;
194 objfile = objfile->next)
196 struct minimal_symbol *msymbol;
198 if (objf == NULL || objf == objfile
199 || objf == objfile->separate_debug_objfile_backlink)
201 /* Do two passes: the first over the ordinary hash table,
202 and the second over the demangled hash table. */
205 for (pass = 1; pass <= 2 && found_symbol.minsym == NULL; pass++)
207 /* Select hash list according to pass. */
209 msymbol = objfile->per_bfd->msymbol_hash[hash];
211 msymbol = objfile->per_bfd->msymbol_demangled_hash[dem_hash];
213 while (msymbol != NULL && found_symbol.minsym == NULL)
219 int (*cmp) (const char *, const char *);
221 cmp = (case_sensitivity == case_sensitive_on
222 ? strcmp : strcasecmp);
223 match = cmp (MSYMBOL_LINKAGE_NAME (msymbol),
228 /* The function respects CASE_SENSITIVITY. */
229 match = MSYMBOL_MATCHES_SEARCH_NAME (msymbol,
235 switch (MSYMBOL_TYPE (msymbol))
241 || filename_cmp (msymbol->filename, sfile) == 0)
243 found_file_symbol.minsym = msymbol;
244 found_file_symbol.objfile = objfile;
248 case mst_solib_trampoline:
250 /* If a trampoline symbol is found, we prefer to
251 keep looking for the *real* symbol. If the
252 actual symbol is not found, then we'll use the
254 if (trampoline_symbol.minsym == NULL)
256 trampoline_symbol.minsym = msymbol;
257 trampoline_symbol.objfile = objfile;
263 found_symbol.minsym = msymbol;
264 found_symbol.objfile = objfile;
269 /* Find the next symbol on the hash chain. */
271 msymbol = msymbol->hash_next;
273 msymbol = msymbol->demangled_hash_next;
280 xfree ((void *) modified_name);
282 /* External symbols are best. */
283 if (found_symbol.minsym != NULL)
286 /* File-local symbols are next best. */
287 if (found_file_symbol.minsym != NULL)
288 return found_file_symbol;
290 /* Symbols for shared library trampolines are next best. */
291 return trampoline_symbol;
296 struct bound_minimal_symbol
297 lookup_bound_minimal_symbol (const char *name)
299 return lookup_minimal_symbol (name, NULL, NULL);
305 iterate_over_minimal_symbols (struct objfile *objf, const char *name,
306 void (*callback) (struct minimal_symbol *,
311 struct minimal_symbol *iter;
312 int (*cmp) (const char *, const char *);
314 /* The first pass is over the ordinary hash table. */
315 hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
316 iter = objf->per_bfd->msymbol_hash[hash];
317 cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);
320 if (cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
321 (*callback) (iter, user_data);
322 iter = iter->hash_next;
325 /* The second pass is over the demangled table. */
326 hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
327 iter = objf->per_bfd->msymbol_demangled_hash[hash];
330 if (MSYMBOL_MATCHES_SEARCH_NAME (iter, name))
331 (*callback) (iter, user_data);
332 iter = iter->demangled_hash_next;
338 struct bound_minimal_symbol
339 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
341 struct objfile *objfile;
342 struct minimal_symbol *msymbol;
343 struct bound_minimal_symbol found_symbol = { NULL, NULL };
344 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
346 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
348 for (objfile = object_files;
349 objfile != NULL && found_symbol.minsym == NULL;
350 objfile = objfile->next)
352 if (objf == NULL || objf == objfile
353 || objf == objfile->separate_debug_objfile_backlink)
355 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
356 msymbol != NULL && found_symbol.minsym == NULL;
357 msymbol = msymbol->hash_next)
359 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
360 (MSYMBOL_TYPE (msymbol) == mst_text
361 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
362 || MSYMBOL_TYPE (msymbol) == mst_file_text))
364 switch (MSYMBOL_TYPE (msymbol))
367 found_file_symbol.minsym = msymbol;
368 found_file_symbol.objfile = objfile;
371 found_symbol.minsym = msymbol;
372 found_symbol.objfile = objfile;
379 /* External symbols are best. */
380 if (found_symbol.minsym)
383 /* File-local symbols are next best. */
384 return found_file_symbol;
389 struct minimal_symbol *
390 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
391 struct objfile *objf)
393 struct objfile *objfile;
394 struct minimal_symbol *msymbol;
396 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
398 for (objfile = object_files;
400 objfile = objfile->next)
402 if (objf == NULL || objf == objfile
403 || objf == objfile->separate_debug_objfile_backlink)
405 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
407 msymbol = msymbol->hash_next)
409 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
410 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
421 struct bound_minimal_symbol
422 lookup_minimal_symbol_solib_trampoline (const char *name,
423 struct objfile *objf)
425 struct objfile *objfile;
426 struct minimal_symbol *msymbol;
427 struct bound_minimal_symbol found_symbol = { NULL, NULL };
429 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
431 for (objfile = object_files;
433 objfile = objfile->next)
435 if (objf == NULL || objf == objfile
436 || objf == objfile->separate_debug_objfile_backlink)
438 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
440 msymbol = msymbol->hash_next)
442 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
443 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
445 found_symbol.objfile = objfile;
446 found_symbol.minsym = msymbol;
456 /* A helper function that makes *PC section-relative. This searches
457 the sections of OBJFILE and if *PC is in a section, it subtracts
458 the section offset and returns true. Otherwise it returns
462 frob_address (struct objfile *objfile, CORE_ADDR *pc)
464 struct obj_section *iter;
466 ALL_OBJFILE_OSECTIONS (objfile, iter)
468 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
470 *pc -= obj_section_offset (iter);
478 /* Search through the minimal symbol table for each objfile and find
479 the symbol whose address is the largest address that is still less
480 than or equal to PC, and matches SECTION (which is not NULL).
481 Returns a pointer to the minimal symbol if such a symbol is found,
482 or NULL if PC is not in a suitable range.
483 Note that we need to look through ALL the minimal symbol tables
484 before deciding on the symbol that comes closest to the specified PC.
485 This is because objfiles can overlap, for example objfile A has .text
486 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
489 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
490 there are text and trampoline symbols at the same address.
491 Otherwise prefer mst_text symbols. */
493 static struct bound_minimal_symbol
494 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc_in,
495 struct obj_section *section,
501 struct objfile *objfile;
502 struct minimal_symbol *msymbol;
503 struct minimal_symbol *best_symbol = NULL;
504 struct objfile *best_objfile = NULL;
505 struct bound_minimal_symbol result;
506 enum minimal_symbol_type want_type, other_type;
508 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
509 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
511 /* We can not require the symbol found to be in section, because
512 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
513 symbol - but find_pc_section won't return an absolute section and
514 hence the code below would skip over absolute symbols. We can
515 still take advantage of the call to find_pc_section, though - the
516 object file still must match. In case we have separate debug
517 files, search both the file and its separate debug file. There's
518 no telling which one will have the minimal symbols. */
520 gdb_assert (section != NULL);
522 for (objfile = section->objfile;
524 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
526 CORE_ADDR pc = pc_in;
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->per_bfd->minimal_symbol_count > 0)
536 int best_zero_sized = -1;
538 msymbol = objfile->per_bfd->msymbols;
540 hi = objfile->per_bfd->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 if (frob_address (objfile, &pc)
561 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
563 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
565 /* pc is still strictly less than highest address. */
566 /* Note "new" will always be >= lo. */
568 if ((MSYMBOL_VALUE_RAW_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->per_bfd->minimal_symbol_count - 1
583 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
584 == MSYMBOL_VALUE_RAW_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 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
615 && (!matching_obj_sections
616 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
623 /* If we are looking for a trampoline and this is a
624 text symbol, or the other way around, check the
625 preceding symbol too. If they are otherwise
626 identical prefer that one. */
628 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
629 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
630 && (MSYMBOL_SIZE (&msymbol[hi])
631 == MSYMBOL_SIZE (&msymbol[hi - 1]))
632 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
633 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
634 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
635 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
641 /* If the minimal symbol has a zero size, save it
642 but keep scanning backwards looking for one with
643 a non-zero size. A zero size may mean that the
644 symbol isn't an object or function (e.g. a
645 label), or it may just mean that the size was not
647 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
648 && best_zero_sized == -1)
650 best_zero_sized = hi;
655 /* If we are past the end of the current symbol, try
656 the previous symbol if it has a larger overlapping
657 size. This happens on i686-pc-linux-gnu with glibc;
658 the nocancel variants of system calls are inside
659 the cancellable variants, but both have sizes. */
661 && MSYMBOL_SIZE (&msymbol[hi]) != 0
662 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
663 + MSYMBOL_SIZE (&msymbol[hi]))
664 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
665 + MSYMBOL_SIZE (&msymbol[hi - 1])))
671 /* Otherwise, this symbol must be as good as we're going
676 /* If HI has a zero size, and best_zero_sized is set,
677 then we had two or more zero-sized symbols; prefer
678 the first one we found (which may have a higher
679 address). Also, if we ran off the end, be sure
681 if (best_zero_sized != -1
682 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
683 hi = best_zero_sized;
685 /* If the minimal symbol has a non-zero size, and this
686 PC appears to be outside the symbol's contents, then
687 refuse to use this symbol. If we found a zero-sized
688 symbol with an address greater than this symbol's,
689 use that instead. We assume that if symbols have
690 specified sizes, they do not overlap. */
693 && MSYMBOL_SIZE (&msymbol[hi]) != 0
694 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
695 + MSYMBOL_SIZE (&msymbol[hi])))
697 if (best_zero_sized != -1)
698 hi = best_zero_sized;
700 /* Go on to the next object file. */
704 /* The minimal symbol indexed by hi now is the best one in this
705 objfile's minimal symbol table. See if it is the best one
709 && ((best_symbol == NULL) ||
710 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
711 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
713 best_symbol = &msymbol[hi];
714 best_objfile = objfile;
720 result.minsym = best_symbol;
721 result.objfile = best_objfile;
725 struct bound_minimal_symbol
726 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
730 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
731 force the section but that (well unless you're doing overlay
732 debugging) always returns NULL making the call somewhat useless. */
733 section = find_pc_section (pc);
736 struct bound_minimal_symbol result;
738 memset (&result, 0, sizeof (result));
742 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
747 struct bound_minimal_symbol
748 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
750 struct obj_section *section = find_pc_section (pc);
754 struct bound_minimal_symbol result;
756 memset (&result, 0, sizeof (result));
759 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
762 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
765 in_gnu_ifunc_stub (CORE_ADDR pc)
767 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
769 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
772 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
775 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
777 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
778 "the ELF support compiled in."),
779 paddress (gdbarch, pc));
782 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
785 stub_gnu_ifunc_resolve_name (const char *function_name,
786 CORE_ADDR *function_address_p)
788 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
789 "the ELF support compiled in."),
793 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
796 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
798 internal_error (__FILE__, __LINE__,
799 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
802 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
805 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
807 internal_error (__FILE__, __LINE__,
808 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
811 /* See elf_gnu_ifunc_fns for its real implementation. */
813 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
815 stub_gnu_ifunc_resolve_addr,
816 stub_gnu_ifunc_resolve_name,
817 stub_gnu_ifunc_resolver_stop,
818 stub_gnu_ifunc_resolver_return_stop,
821 /* A placeholder for &elf_gnu_ifunc_fns. */
823 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
827 struct bound_minimal_symbol
828 lookup_minimal_symbol_and_objfile (const char *name)
830 struct bound_minimal_symbol result;
831 struct objfile *objfile;
832 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
834 ALL_OBJFILES (objfile)
836 struct minimal_symbol *msym;
838 for (msym = objfile->per_bfd->msymbol_hash[hash];
840 msym = msym->hash_next)
842 if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
844 result.minsym = msym;
845 result.objfile = objfile;
851 memset (&result, 0, sizeof (result));
856 /* Return leading symbol character for a BFD. If BFD is NULL,
857 return the leading symbol character from the main objfile. */
860 get_symbol_leading_char (bfd *abfd)
863 return bfd_get_symbol_leading_char (abfd);
864 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
865 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
872 init_minimal_symbol_collection (void)
876 /* Note that presetting msym_bunch_index to BUNCH_SIZE causes the
877 first call to save a minimal symbol to allocate the memory for
879 msym_bunch_index = BUNCH_SIZE;
885 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
886 enum minimal_symbol_type ms_type,
887 struct objfile *objfile)
894 case mst_text_gnu_ifunc:
896 case mst_solib_trampoline:
897 section = SECT_OFF_TEXT (objfile);
901 section = SECT_OFF_DATA (objfile);
905 section = SECT_OFF_BSS (objfile);
911 prim_record_minimal_symbol_and_info (name, address, ms_type,
917 struct minimal_symbol *
918 prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
920 enum minimal_symbol_type ms_type,
922 struct objfile *objfile)
924 struct obj_section *obj_section;
925 struct msym_bunch *new;
926 struct minimal_symbol *msymbol;
928 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
929 the minimal symbols, because if there is also another symbol
930 at the same address (e.g. the first function of the file),
931 lookup_minimal_symbol_by_pc would have no way of getting the
933 if (ms_type == mst_file_text && name[0] == 'g'
934 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
935 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
938 /* It's safe to strip the leading char here once, since the name
939 is also stored stripped in the minimal symbol table. */
940 if (name[0] == get_symbol_leading_char (objfile->obfd))
946 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
949 if (msym_bunch_index == BUNCH_SIZE)
951 new = XCNEW (struct msym_bunch);
952 msym_bunch_index = 0;
953 new->next = msym_bunch;
956 msymbol = &msym_bunch->contents[msym_bunch_index];
957 MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
958 &objfile->per_bfd->storage_obstack);
959 MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, objfile);
961 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
962 MSYMBOL_SECTION (msymbol) = section;
964 MSYMBOL_TYPE (msymbol) = ms_type;
965 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
966 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
967 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
968 as it would also set the has_size flag. */
971 /* The hash pointers must be cleared! If they're not,
972 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
973 msymbol->hash_next = NULL;
974 msymbol->demangled_hash_next = NULL;
976 /* If we already read minimal symbols for this objfile, then don't
977 ever allocate a new one. */
978 if (!objfile->per_bfd->minsyms_read)
981 objfile->per_bfd->n_minsyms++;
989 struct minimal_symbol *
990 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
991 enum minimal_symbol_type ms_type,
993 struct objfile *objfile)
995 return prim_record_minimal_symbol_full (name, strlen (name), 1,
1000 /* Compare two minimal symbols by address and return a signed result based
1001 on unsigned comparisons, so that we sort into unsigned numeric order.
1002 Within groups with the same address, sort by name. */
1005 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1007 const struct minimal_symbol *fn1;
1008 const struct minimal_symbol *fn2;
1010 fn1 = (const struct minimal_symbol *) fn1p;
1011 fn2 = (const struct minimal_symbol *) fn2p;
1013 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1015 return (-1); /* addr 1 is less than addr 2. */
1017 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1019 return (1); /* addr 1 is greater than addr 2. */
1022 /* addrs are equal: sort by name */
1024 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1025 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1027 if (name1 && name2) /* both have names */
1028 return strcmp (name1, name2);
1030 return 1; /* fn1 has no name, so it is "less". */
1031 else if (name1) /* fn2 has no name, so it is "less". */
1034 return (0); /* Neither has a name, so they're equal. */
1038 /* Discard the currently collected minimal symbols, if any. If we wish
1039 to save them for later use, we must have already copied them somewhere
1040 else before calling this function.
1042 FIXME: We could allocate the minimal symbol bunches on their own
1043 obstack and then simply blow the obstack away when we are done with
1044 it. Is it worth the extra trouble though? */
1047 do_discard_minimal_symbols_cleanup (void *arg)
1049 struct msym_bunch *next;
1051 while (msym_bunch != NULL)
1053 next = msym_bunch->next;
1059 /* See minsyms.h. */
1062 make_cleanup_discard_minimal_symbols (void)
1064 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
1069 /* Compact duplicate entries out of a minimal symbol table by walking
1070 through the table and compacting out entries with duplicate addresses
1071 and matching names. Return the number of entries remaining.
1073 On entry, the table resides between msymbol[0] and msymbol[mcount].
1074 On exit, it resides between msymbol[0] and msymbol[result_count].
1076 When files contain multiple sources of symbol information, it is
1077 possible for the minimal symbol table to contain many duplicate entries.
1078 As an example, SVR4 systems use ELF formatted object files, which
1079 usually contain at least two different types of symbol tables (a
1080 standard ELF one and a smaller dynamic linking table), as well as
1081 DWARF debugging information for files compiled with -g.
1083 Without compacting, the minimal symbol table for gdb itself contains
1084 over a 1000 duplicates, about a third of the total table size. Aside
1085 from the potential trap of not noticing that two successive entries
1086 identify the same location, this duplication impacts the time required
1087 to linearly scan the table, which is done in a number of places. So we
1088 just do one linear scan here and toss out the duplicates.
1090 Note that we are not concerned here about recovering the space that
1091 is potentially freed up, because the strings themselves are allocated
1092 on the storage_obstack, and will get automatically freed when the symbol
1093 table is freed. The caller can free up the unused minimal symbols at
1094 the end of the compacted region if their allocation strategy allows it.
1096 Also note we only go up to the next to last entry within the loop
1097 and then copy the last entry explicitly after the loop terminates.
1099 Since the different sources of information for each symbol may
1100 have different levels of "completeness", we may have duplicates
1101 that have one entry with type "mst_unknown" and the other with a
1102 known type. So if the one we are leaving alone has type mst_unknown,
1103 overwrite its type with the type from the one we are compacting out. */
1106 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1107 struct objfile *objfile)
1109 struct minimal_symbol *copyfrom;
1110 struct minimal_symbol *copyto;
1114 copyfrom = copyto = msymbol;
1115 while (copyfrom < msymbol + mcount - 1)
1117 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1118 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1119 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1120 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1121 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1123 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1125 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1130 *copyto++ = *copyfrom++;
1132 *copyto++ = *copyfrom++;
1133 mcount = copyto - msymbol;
1138 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1139 after compacting or sorting the table since the entries move around
1140 thus causing the internal minimal_symbol pointers to become jumbled. */
1143 build_minimal_symbol_hash_tables (struct objfile *objfile)
1146 struct minimal_symbol *msym;
1148 /* Clear the hash tables. */
1149 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1151 objfile->per_bfd->msymbol_hash[i] = 0;
1152 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1155 /* Now, (re)insert the actual entries. */
1156 for ((i = objfile->per_bfd->minimal_symbol_count,
1157 msym = objfile->per_bfd->msymbols);
1161 msym->hash_next = 0;
1162 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1164 msym->demangled_hash_next = 0;
1165 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1166 add_minsym_to_demangled_hash_table (msym,
1167 objfile->per_bfd->msymbol_demangled_hash);
1171 /* Add the minimal symbols in the existing bunches to the objfile's official
1172 minimal symbol table. In most cases there is no minimal symbol table yet
1173 for this objfile, and the existing bunches are used to create one. Once
1174 in a while (for shared libraries for example), we add symbols (e.g. common
1175 symbols) to an existing objfile.
1177 Because of the way minimal symbols are collected, we generally have no way
1178 of knowing what source language applies to any particular minimal symbol.
1179 Specifically, we have no way of knowing if the minimal symbol comes from a
1180 C++ compilation unit or not. So for the sake of supporting cached
1181 demangled C++ names, we have no choice but to try and demangle each new one
1182 that comes in. If the demangling succeeds, then we assume it is a C++
1183 symbol and set the symbol's language and demangled name fields
1184 appropriately. Note that in order to avoid unnecessary demanglings, and
1185 allocating obstack space that subsequently can't be freed for the demangled
1186 names, we mark all newly added symbols with language_auto. After
1187 compaction of the minimal symbols, we go back and scan the entire minimal
1188 symbol table looking for these new symbols. For each new symbol we attempt
1189 to demangle it, and if successful, record it as a language_cplus symbol
1190 and cache the demangled form on the symbol obstack. Symbols which don't
1191 demangle are marked as language_unknown symbols, which inhibits future
1192 attempts to demangle them if we later add more minimal symbols. */
1195 install_minimal_symbols (struct objfile *objfile)
1199 struct msym_bunch *bunch;
1200 struct minimal_symbol *msymbols;
1203 if (objfile->per_bfd->minsyms_read)
1208 if (symtab_create_debug)
1210 fprintf_unfiltered (gdb_stdlog,
1211 "Installing %d minimal symbols of objfile %s.\n",
1212 msym_count, objfile_name (objfile));
1215 /* Allocate enough space in the obstack, into which we will gather the
1216 bunches of new and existing minimal symbols, sort them, and then
1217 compact out the duplicate entries. Once we have a final table,
1218 we will give back the excess space. */
1220 alloc_count = msym_count + objfile->per_bfd->minimal_symbol_count + 1;
1221 obstack_blank (&objfile->per_bfd->storage_obstack,
1222 alloc_count * sizeof (struct minimal_symbol));
1223 msymbols = (struct minimal_symbol *)
1224 obstack_base (&objfile->per_bfd->storage_obstack);
1226 /* Copy in the existing minimal symbols, if there are any. */
1228 if (objfile->per_bfd->minimal_symbol_count)
1229 memcpy ((char *) msymbols, (char *) objfile->per_bfd->msymbols,
1230 objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol));
1232 /* Walk through the list of minimal symbol bunches, adding each symbol
1233 to the new contiguous array of symbols. Note that we start with the
1234 current, possibly partially filled bunch (thus we use the current
1235 msym_bunch_index for the first bunch we copy over), and thereafter
1236 each bunch is full. */
1238 mcount = objfile->per_bfd->minimal_symbol_count;
1240 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1242 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1243 msymbols[mcount] = bunch->contents[bindex];
1244 msym_bunch_index = BUNCH_SIZE;
1247 /* Sort the minimal symbols by address. */
1249 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1250 compare_minimal_symbols);
1252 /* Compact out any duplicates, and free up whatever space we are
1255 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1257 obstack_blank (&objfile->per_bfd->storage_obstack,
1258 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1259 msymbols = (struct minimal_symbol *)
1260 obstack_finish (&objfile->per_bfd->storage_obstack);
1262 /* We also terminate the minimal symbol table with a "null symbol",
1263 which is *not* included in the size of the table. This makes it
1264 easier to find the end of the table when we are handed a pointer
1265 to some symbol in the middle of it. Zero out the fields in the
1266 "null symbol" allocated at the end of the array. Note that the
1267 symbol count does *not* include this null symbol, which is why it
1268 is indexed by mcount and not mcount-1. */
1270 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1272 /* Attach the minimal symbol table to the specified objfile.
1273 The strings themselves are also located in the storage_obstack
1276 objfile->per_bfd->minimal_symbol_count = mcount;
1277 objfile->per_bfd->msymbols = msymbols;
1279 /* Now build the hash tables; we can't do this incrementally
1280 at an earlier point since we weren't finished with the obstack
1281 yet. (And if the msymbol obstack gets moved, all the internal
1282 pointers to other msymbols need to be adjusted.) */
1283 build_minimal_symbol_hash_tables (objfile);
1287 /* See minsyms.h. */
1290 terminate_minimal_symbol_table (struct objfile *objfile)
1292 if (! objfile->per_bfd->msymbols)
1293 objfile->per_bfd->msymbols
1294 = ((struct minimal_symbol *)
1295 obstack_alloc (&objfile->per_bfd->storage_obstack,
1296 sizeof (struct minimal_symbol)));
1299 struct minimal_symbol *m
1300 = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1302 memset (m, 0, sizeof (*m));
1303 /* Don't rely on these enumeration values being 0's. */
1304 MSYMBOL_TYPE (m) = mst_unknown;
1305 MSYMBOL_SET_LANGUAGE (m, language_unknown,
1306 &objfile->per_bfd->storage_obstack);
1310 /* Check if PC is in a shared library trampoline code stub.
1311 Return minimal symbol for the trampoline entry or NULL if PC is not
1312 in a trampoline code stub. */
1314 static struct minimal_symbol *
1315 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1317 struct obj_section *section = find_pc_section (pc);
1318 struct bound_minimal_symbol msymbol;
1320 if (section == NULL)
1322 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1324 if (msymbol.minsym != NULL
1325 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1326 return msymbol.minsym;
1330 /* If PC is in a shared library trampoline code stub, return the
1331 address of the `real' function belonging to the stub.
1332 Return 0 if PC is not in a trampoline code stub or if the real
1333 function is not found in the minimal symbol table.
1335 We may fail to find the right function if a function with the
1336 same name is defined in more than one shared library, but this
1337 is considered bad programming style. We could return 0 if we find
1338 a duplicate function in case this matters someday. */
1341 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1343 struct objfile *objfile;
1344 struct minimal_symbol *msymbol;
1345 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1347 if (tsymbol != NULL)
1349 ALL_MSYMBOLS (objfile, msymbol)
1351 if ((MSYMBOL_TYPE (msymbol) == mst_text
1352 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1353 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1354 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1355 return MSYMBOL_VALUE_ADDRESS (objfile, msymbol);
1357 /* Also handle minimal symbols pointing to function descriptors. */
1358 if (MSYMBOL_TYPE (msymbol) == mst_data
1359 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1360 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1364 func = gdbarch_convert_from_func_ptr_addr
1365 (get_objfile_arch (objfile),
1366 MSYMBOL_VALUE_ADDRESS (objfile, msymbol),
1369 /* Ignore data symbols that are not function descriptors. */
1370 if (func != MSYMBOL_VALUE_ADDRESS (objfile, msymbol))
1378 /* See minsyms.h. */
1381 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1385 struct obj_section *obj_section;
1387 struct minimal_symbol *msymbol;
1389 gdb_assert (minsym.minsym != NULL);
1391 /* If the minimal symbol has a size, use it. Otherwise use the
1392 lesser of the next minimal symbol in the same section, or the end
1393 of the section, as the end of the function. */
1395 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1396 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1398 /* Step over other symbols at this same address, and symbols in
1399 other sections, to find the next symbol in this section with a
1400 different address. */
1402 msymbol = minsym.minsym;
1403 section = MSYMBOL_SECTION (msymbol);
1404 for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1406 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1407 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1408 && MSYMBOL_SECTION (msymbol + i) == section)
1412 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1413 if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1414 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1415 < obj_section_endaddr (obj_section)))
1416 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
1418 /* We got the start address from the last msymbol in the objfile.
1419 So the end address is the end of the section. */
1420 result = obj_section_endaddr (obj_section);