1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2013 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"
53 #include "cli/cli-utils.h"
55 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
56 At the end, copy them all into one newly allocated location on an objfile's
59 #define BUNCH_SIZE 127
63 struct msym_bunch *next;
64 struct minimal_symbol contents[BUNCH_SIZE];
67 /* Bunch currently being filled up.
68 The next field points to chain of filled bunches. */
70 static struct msym_bunch *msym_bunch;
72 /* Number of slots filled in current bunch. */
74 static int msym_bunch_index;
76 /* Total number of minimal symbols recorded so far for the objfile. */
78 static int msym_count;
83 msymbol_hash_iw (const char *string)
85 unsigned int hash = 0;
87 while (*string && *string != '(')
89 string = skip_spaces_const (string);
90 if (*string && *string != '(')
92 hash = SYMBOL_HASH_NEXT (hash, *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];
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;
314 iterate_over_minimal_symbols (struct objfile *objf, const char *name,
315 void (*callback) (struct minimal_symbol *,
320 struct minimal_symbol *iter;
321 int (*cmp) (const char *, const char *);
323 /* The first pass is over the ordinary hash table. */
324 hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
325 iter = objf->msymbol_hash[hash];
326 cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);
329 if (cmp (SYMBOL_LINKAGE_NAME (iter), name) == 0)
330 (*callback) (iter, user_data);
331 iter = iter->hash_next;
334 /* The second pass is over the demangled table. */
335 hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
336 iter = objf->msymbol_demangled_hash[hash];
339 if (SYMBOL_MATCHES_SEARCH_NAME (iter, name))
340 (*callback) (iter, user_data);
341 iter = iter->demangled_hash_next;
347 struct minimal_symbol *
348 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
350 struct objfile *objfile;
351 struct minimal_symbol *msymbol;
352 struct minimal_symbol *found_symbol = NULL;
353 struct minimal_symbol *found_file_symbol = NULL;
355 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
357 for (objfile = object_files;
358 objfile != NULL && found_symbol == NULL;
359 objfile = objfile->next)
361 if (objf == NULL || objf == objfile
362 || objf == objfile->separate_debug_objfile_backlink)
364 for (msymbol = objfile->msymbol_hash[hash];
365 msymbol != NULL && found_symbol == NULL;
366 msymbol = msymbol->hash_next)
368 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
369 (MSYMBOL_TYPE (msymbol) == mst_text
370 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
371 || MSYMBOL_TYPE (msymbol) == mst_file_text))
373 switch (MSYMBOL_TYPE (msymbol))
376 found_file_symbol = msymbol;
379 found_symbol = msymbol;
386 /* External symbols are best. */
390 /* File-local symbols are next best. */
391 if (found_file_symbol)
392 return found_file_symbol;
399 struct minimal_symbol *
400 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
401 struct objfile *objf)
403 struct objfile *objfile;
404 struct minimal_symbol *msymbol;
406 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
408 for (objfile = object_files;
410 objfile = objfile->next)
412 if (objf == NULL || objf == objfile
413 || objf == objfile->separate_debug_objfile_backlink)
415 for (msymbol = objfile->msymbol_hash[hash];
417 msymbol = msymbol->hash_next)
419 if (SYMBOL_VALUE_ADDRESS (msymbol) == pc
420 && strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0)
431 struct minimal_symbol *
432 lookup_minimal_symbol_solib_trampoline (const char *name,
433 struct objfile *objf)
435 struct objfile *objfile;
436 struct minimal_symbol *msymbol;
437 struct minimal_symbol *found_symbol = NULL;
439 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
441 for (objfile = object_files;
442 objfile != NULL && found_symbol == NULL;
443 objfile = objfile->next)
445 if (objf == NULL || objf == objfile
446 || objf == objfile->separate_debug_objfile_backlink)
448 for (msymbol = objfile->msymbol_hash[hash];
449 msymbol != NULL && found_symbol == NULL;
450 msymbol = msymbol->hash_next)
452 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
453 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
462 /* Search through the minimal symbol table for each objfile and find
463 the symbol whose address is the largest address that is still less
464 than or equal to PC, and matches SECTION (which is not NULL).
465 Returns a pointer to the minimal symbol if such a symbol is found,
466 or NULL if PC is not in a suitable range.
467 Note that we need to look through ALL the minimal symbol tables
468 before deciding on the symbol that comes closest to the specified PC.
469 This is because objfiles can overlap, for example objfile A has .text
470 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
473 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
474 there are text and trampoline symbols at the same address.
475 Otherwise prefer mst_text symbols. */
477 static struct bound_minimal_symbol
478 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc,
479 struct obj_section *section,
485 struct objfile *objfile;
486 struct minimal_symbol *msymbol;
487 struct minimal_symbol *best_symbol = NULL;
488 struct objfile *best_objfile = NULL;
489 struct bound_minimal_symbol result;
490 enum minimal_symbol_type want_type, other_type;
492 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
493 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
495 /* We can not require the symbol found to be in section, because
496 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
497 symbol - but find_pc_section won't return an absolute section and
498 hence the code below would skip over absolute symbols. We can
499 still take advantage of the call to find_pc_section, though - the
500 object file still must match. In case we have separate debug
501 files, search both the file and its separate debug file. There's
502 no telling which one will have the minimal symbols. */
504 gdb_assert (section != NULL);
506 for (objfile = section->objfile;
508 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
510 /* If this objfile has a minimal symbol table, go search it using
511 a binary search. Note that a minimal symbol table always consists
512 of at least two symbols, a "real" symbol and the terminating
513 "null symbol". If there are no real symbols, then there is no
514 minimal symbol table at all. */
516 if (objfile->minimal_symbol_count > 0)
518 int best_zero_sized = -1;
520 msymbol = objfile->msymbols;
522 hi = objfile->minimal_symbol_count - 1;
524 /* This code assumes that the minimal symbols are sorted by
525 ascending address values. If the pc value is greater than or
526 equal to the first symbol's address, then some symbol in this
527 minimal symbol table is a suitable candidate for being the
528 "best" symbol. This includes the last real symbol, for cases
529 where the pc value is larger than any address in this vector.
531 By iterating until the address associated with the current
532 hi index (the endpoint of the test interval) is less than
533 or equal to the desired pc value, we accomplish two things:
534 (1) the case where the pc value is larger than any minimal
535 symbol address is trivially solved, (2) the address associated
536 with the hi index is always the one we want when the interation
537 terminates. In essence, we are iterating the test interval
538 down until the pc value is pushed out of it from the high end.
540 Warning: this code is trickier than it would appear at first. */
542 /* Should also require that pc is <= end of objfile. FIXME! */
543 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
545 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
547 /* pc is still strictly less than highest address. */
548 /* Note "new" will always be >= lo. */
550 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
561 /* If we have multiple symbols at the same address, we want
562 hi to point to the last one. That way we can find the
563 right symbol if it has an index greater than hi. */
564 while (hi < objfile->minimal_symbol_count - 1
565 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
566 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
569 /* Skip various undesirable symbols. */
572 /* Skip any absolute symbols. This is apparently
573 what adb and dbx do, and is needed for the CM-5.
574 There are two known possible problems: (1) on
575 ELF, apparently end, edata, etc. are absolute.
576 Not sure ignoring them here is a big deal, but if
577 we want to use them, the fix would go in
578 elfread.c. (2) I think shared library entry
579 points on the NeXT are absolute. If we want
580 special handling for this it probably should be
581 triggered by a special mst_abs_or_lib or some
584 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
590 /* If SECTION was specified, skip any symbol from
593 /* Some types of debug info, such as COFF,
594 don't fill the bfd_section member, so don't
595 throw away symbols on those platforms. */
596 && SYMBOL_OBJ_SECTION (&msymbol[hi]) != NULL
597 && (!matching_obj_sections
598 (SYMBOL_OBJ_SECTION (&msymbol[hi]), section)))
604 /* If we are looking for a trampoline and this is a
605 text symbol, or the other way around, check the
606 preceding symbol too. If they are otherwise
607 identical prefer that one. */
609 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
610 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
611 && (MSYMBOL_SIZE (&msymbol[hi])
612 == MSYMBOL_SIZE (&msymbol[hi - 1]))
613 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
614 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
615 && (SYMBOL_OBJ_SECTION (&msymbol[hi])
616 == SYMBOL_OBJ_SECTION (&msymbol[hi - 1])))
622 /* If the minimal symbol has a zero size, save it
623 but keep scanning backwards looking for one with
624 a non-zero size. A zero size may mean that the
625 symbol isn't an object or function (e.g. a
626 label), or it may just mean that the size was not
628 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
629 && best_zero_sized == -1)
631 best_zero_sized = hi;
636 /* If we are past the end of the current symbol, try
637 the previous symbol if it has a larger overlapping
638 size. This happens on i686-pc-linux-gnu with glibc;
639 the nocancel variants of system calls are inside
640 the cancellable variants, but both have sizes. */
642 && MSYMBOL_SIZE (&msymbol[hi]) != 0
643 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
644 + MSYMBOL_SIZE (&msymbol[hi]))
645 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
646 + MSYMBOL_SIZE (&msymbol[hi - 1])))
652 /* Otherwise, this symbol must be as good as we're going
657 /* If HI has a zero size, and best_zero_sized is set,
658 then we had two or more zero-sized symbols; prefer
659 the first one we found (which may have a higher
660 address). Also, if we ran off the end, be sure
662 if (best_zero_sized != -1
663 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
664 hi = best_zero_sized;
666 /* If the minimal symbol has a non-zero size, and this
667 PC appears to be outside the symbol's contents, then
668 refuse to use this symbol. If we found a zero-sized
669 symbol with an address greater than this symbol's,
670 use that instead. We assume that if symbols have
671 specified sizes, they do not overlap. */
674 && MSYMBOL_SIZE (&msymbol[hi]) != 0
675 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
676 + MSYMBOL_SIZE (&msymbol[hi])))
678 if (best_zero_sized != -1)
679 hi = best_zero_sized;
681 /* Go on to the next object file. */
685 /* The minimal symbol indexed by hi now is the best one in this
686 objfile's minimal symbol table. See if it is the best one
690 && ((best_symbol == NULL) ||
691 (SYMBOL_VALUE_ADDRESS (best_symbol) <
692 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
694 best_symbol = &msymbol[hi];
695 best_objfile = objfile;
701 result.minsym = best_symbol;
702 result.objfile = best_objfile;
706 struct bound_minimal_symbol
707 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
711 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
712 force the section but that (well unless you're doing overlay
713 debugging) always returns NULL making the call somewhat useless. */
714 section = find_pc_section (pc);
717 struct bound_minimal_symbol result;
719 memset (&result, 0, sizeof (result));
723 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
728 struct bound_minimal_symbol
729 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
731 struct obj_section *section = find_pc_section (pc);
735 struct bound_minimal_symbol result;
737 memset (&result, 0, sizeof (result));
740 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
743 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
746 in_gnu_ifunc_stub (CORE_ADDR pc)
748 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
750 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
753 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
756 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
758 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
759 "the ELF support compiled in."),
760 paddress (gdbarch, pc));
763 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
766 stub_gnu_ifunc_resolve_name (const char *function_name,
767 CORE_ADDR *function_address_p)
769 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
770 "the ELF support compiled in."),
774 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
777 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
779 internal_error (__FILE__, __LINE__,
780 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
783 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
786 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
788 internal_error (__FILE__, __LINE__,
789 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
792 /* See elf_gnu_ifunc_fns for its real implementation. */
794 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
796 stub_gnu_ifunc_resolve_addr,
797 stub_gnu_ifunc_resolve_name,
798 stub_gnu_ifunc_resolver_stop,
799 stub_gnu_ifunc_resolver_return_stop,
802 /* A placeholder for &elf_gnu_ifunc_fns. */
804 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
808 struct bound_minimal_symbol
809 lookup_minimal_symbol_and_objfile (const char *name)
811 struct bound_minimal_symbol result;
812 struct objfile *objfile;
813 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
815 ALL_OBJFILES (objfile)
817 struct minimal_symbol *msym;
819 for (msym = objfile->msymbol_hash[hash];
821 msym = msym->hash_next)
823 if (strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
825 result.minsym = msym;
826 result.objfile = objfile;
832 memset (&result, 0, sizeof (result));
837 /* Return leading symbol character for a BFD. If BFD is NULL,
838 return the leading symbol character from the main objfile. */
840 static int get_symbol_leading_char (bfd *);
843 get_symbol_leading_char (bfd *abfd)
846 return bfd_get_symbol_leading_char (abfd);
847 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
848 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
855 init_minimal_symbol_collection (void)
859 /* Note that presetting msym_bunch_index to BUNCH_SIZE causes the
860 first call to save a minimal symbol to allocate the memory for
862 msym_bunch_index = BUNCH_SIZE;
868 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
869 enum minimal_symbol_type ms_type,
870 struct objfile *objfile)
877 case mst_text_gnu_ifunc:
879 case mst_solib_trampoline:
880 section = SECT_OFF_TEXT (objfile);
884 section = SECT_OFF_DATA (objfile);
888 section = SECT_OFF_BSS (objfile);
894 prim_record_minimal_symbol_and_info (name, address, ms_type,
895 section, NULL, objfile);
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, &objfile->objfile_obstack);
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 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
963 as it would also set the has_size flag. */
966 /* The hash pointers must be cleared! If they're not,
967 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
968 msymbol->hash_next = NULL;
969 msymbol->demangled_hash_next = NULL;
973 OBJSTAT (objfile, n_minsyms++);
979 struct minimal_symbol *
980 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
981 enum minimal_symbol_type ms_type,
983 asection *bfd_section,
984 struct objfile *objfile)
986 return prim_record_minimal_symbol_full (name, strlen (name), 1,
987 address, ms_type, section,
988 bfd_section, objfile);
991 /* Compare two minimal symbols by address and return a signed result based
992 on unsigned comparisons, so that we sort into unsigned numeric order.
993 Within groups with the same address, sort by name. */
996 compare_minimal_symbols (const void *fn1p, const void *fn2p)
998 const struct minimal_symbol *fn1;
999 const struct minimal_symbol *fn2;
1001 fn1 = (const struct minimal_symbol *) fn1p;
1002 fn2 = (const struct minimal_symbol *) fn2p;
1004 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
1006 return (-1); /* addr 1 is less than addr 2. */
1008 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
1010 return (1); /* addr 1 is greater than addr 2. */
1013 /* addrs are equal: sort by name */
1015 const char *name1 = SYMBOL_LINKAGE_NAME (fn1);
1016 const char *name2 = SYMBOL_LINKAGE_NAME (fn2);
1018 if (name1 && name2) /* both have names */
1019 return strcmp (name1, name2);
1021 return 1; /* fn1 has no name, so it is "less". */
1022 else if (name1) /* fn2 has no name, so it is "less". */
1025 return (0); /* Neither has a name, so they're equal. */
1029 /* Discard the currently collected minimal symbols, if any. If we wish
1030 to save them for later use, we must have already copied them somewhere
1031 else before calling this function.
1033 FIXME: We could allocate the minimal symbol bunches on their own
1034 obstack and then simply blow the obstack away when we are done with
1035 it. Is it worth the extra trouble though? */
1038 do_discard_minimal_symbols_cleanup (void *arg)
1040 struct msym_bunch *next;
1042 while (msym_bunch != NULL)
1044 next = msym_bunch->next;
1050 /* See minsyms.h. */
1053 make_cleanup_discard_minimal_symbols (void)
1055 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
1060 /* Compact duplicate entries out of a minimal symbol table by walking
1061 through the table and compacting out entries with duplicate addresses
1062 and matching names. Return the number of entries remaining.
1064 On entry, the table resides between msymbol[0] and msymbol[mcount].
1065 On exit, it resides between msymbol[0] and msymbol[result_count].
1067 When files contain multiple sources of symbol information, it is
1068 possible for the minimal symbol table to contain many duplicate entries.
1069 As an example, SVR4 systems use ELF formatted object files, which
1070 usually contain at least two different types of symbol tables (a
1071 standard ELF one and a smaller dynamic linking table), as well as
1072 DWARF debugging information for files compiled with -g.
1074 Without compacting, the minimal symbol table for gdb itself contains
1075 over a 1000 duplicates, about a third of the total table size. Aside
1076 from the potential trap of not noticing that two successive entries
1077 identify the same location, this duplication impacts the time required
1078 to linearly scan the table, which is done in a number of places. So we
1079 just do one linear scan here and toss out the duplicates.
1081 Note that we are not concerned here about recovering the space that
1082 is potentially freed up, because the strings themselves are allocated
1083 on the objfile_obstack, and will get automatically freed when the symbol
1084 table is freed. The caller can free up the unused minimal symbols at
1085 the end of the compacted region if their allocation strategy allows it.
1087 Also note we only go up to the next to last entry within the loop
1088 and then copy the last entry explicitly after the loop terminates.
1090 Since the different sources of information for each symbol may
1091 have different levels of "completeness", we may have duplicates
1092 that have one entry with type "mst_unknown" and the other with a
1093 known type. So if the one we are leaving alone has type mst_unknown,
1094 overwrite its type with the type from the one we are compacting out. */
1097 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1098 struct objfile *objfile)
1100 struct minimal_symbol *copyfrom;
1101 struct minimal_symbol *copyto;
1105 copyfrom = copyto = msymbol;
1106 while (copyfrom < msymbol + mcount - 1)
1108 if (SYMBOL_VALUE_ADDRESS (copyfrom)
1109 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
1110 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
1111 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1113 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1115 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1120 *copyto++ = *copyfrom++;
1122 *copyto++ = *copyfrom++;
1123 mcount = copyto - msymbol;
1128 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1129 after compacting or sorting the table since the entries move around
1130 thus causing the internal minimal_symbol pointers to become jumbled. */
1133 build_minimal_symbol_hash_tables (struct objfile *objfile)
1136 struct minimal_symbol *msym;
1138 /* Clear the hash tables. */
1139 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1141 objfile->msymbol_hash[i] = 0;
1142 objfile->msymbol_demangled_hash[i] = 0;
1145 /* Now, (re)insert the actual entries. */
1146 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
1150 msym->hash_next = 0;
1151 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
1153 msym->demangled_hash_next = 0;
1154 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
1155 add_minsym_to_demangled_hash_table (msym,
1156 objfile->msymbol_demangled_hash);
1160 /* Add the minimal symbols in the existing bunches to the objfile's official
1161 minimal symbol table. In most cases there is no minimal symbol table yet
1162 for this objfile, and the existing bunches are used to create one. Once
1163 in a while (for shared libraries for example), we add symbols (e.g. common
1164 symbols) to an existing objfile.
1166 Because of the way minimal symbols are collected, we generally have no way
1167 of knowing what source language applies to any particular minimal symbol.
1168 Specifically, we have no way of knowing if the minimal symbol comes from a
1169 C++ compilation unit or not. So for the sake of supporting cached
1170 demangled C++ names, we have no choice but to try and demangle each new one
1171 that comes in. If the demangling succeeds, then we assume it is a C++
1172 symbol and set the symbol's language and demangled name fields
1173 appropriately. Note that in order to avoid unnecessary demanglings, and
1174 allocating obstack space that subsequently can't be freed for the demangled
1175 names, we mark all newly added symbols with language_auto. After
1176 compaction of the minimal symbols, we go back and scan the entire minimal
1177 symbol table looking for these new symbols. For each new symbol we attempt
1178 to demangle it, and if successful, record it as a language_cplus symbol
1179 and cache the demangled form on the symbol obstack. Symbols which don't
1180 demangle are marked as language_unknown symbols, which inhibits future
1181 attempts to demangle them if we later add more minimal symbols. */
1184 install_minimal_symbols (struct objfile *objfile)
1188 struct msym_bunch *bunch;
1189 struct minimal_symbol *msymbols;
1194 if (symtab_create_debug)
1196 fprintf_unfiltered (gdb_stdlog,
1197 "Installing %d minimal symbols of objfile %s.\n",
1198 msym_count, objfile->name);
1201 /* Allocate enough space in the obstack, into which we will gather the
1202 bunches of new and existing minimal symbols, sort them, and then
1203 compact out the duplicate entries. Once we have a final table,
1204 we will give back the excess space. */
1206 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1207 obstack_blank (&objfile->objfile_obstack,
1208 alloc_count * sizeof (struct minimal_symbol));
1209 msymbols = (struct minimal_symbol *)
1210 obstack_base (&objfile->objfile_obstack);
1212 /* Copy in the existing minimal symbols, if there are any. */
1214 if (objfile->minimal_symbol_count)
1215 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1216 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1218 /* Walk through the list of minimal symbol bunches, adding each symbol
1219 to the new contiguous array of symbols. Note that we start with the
1220 current, possibly partially filled bunch (thus we use the current
1221 msym_bunch_index for the first bunch we copy over), and thereafter
1222 each bunch is full. */
1224 mcount = objfile->minimal_symbol_count;
1226 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1228 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1229 msymbols[mcount] = bunch->contents[bindex];
1230 msym_bunch_index = BUNCH_SIZE;
1233 /* Sort the minimal symbols by address. */
1235 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1236 compare_minimal_symbols);
1238 /* Compact out any duplicates, and free up whatever space we are
1241 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1243 obstack_blank (&objfile->objfile_obstack,
1244 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1245 msymbols = (struct minimal_symbol *)
1246 obstack_finish (&objfile->objfile_obstack);
1248 /* We also terminate the minimal symbol table with a "null symbol",
1249 which is *not* included in the size of the table. This makes it
1250 easier to find the end of the table when we are handed a pointer
1251 to some symbol in the middle of it. Zero out the fields in the
1252 "null symbol" allocated at the end of the array. Note that the
1253 symbol count does *not* include this null symbol, which is why it
1254 is indexed by mcount and not mcount-1. */
1256 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1258 /* Attach the minimal symbol table to the specified objfile.
1259 The strings themselves are also located in the objfile_obstack
1262 objfile->minimal_symbol_count = mcount;
1263 objfile->msymbols = msymbols;
1265 /* Now build the hash tables; we can't do this incrementally
1266 at an earlier point since we weren't finished with the obstack
1267 yet. (And if the msymbol obstack gets moved, all the internal
1268 pointers to other msymbols need to be adjusted.) */
1269 build_minimal_symbol_hash_tables (objfile);
1273 /* See minsyms.h. */
1276 terminate_minimal_symbol_table (struct objfile *objfile)
1278 if (! objfile->msymbols)
1279 objfile->msymbols = ((struct minimal_symbol *)
1280 obstack_alloc (&objfile->objfile_obstack,
1281 sizeof (objfile->msymbols[0])));
1284 struct minimal_symbol *m
1285 = &objfile->msymbols[objfile->minimal_symbol_count];
1287 memset (m, 0, sizeof (*m));
1288 /* Don't rely on these enumeration values being 0's. */
1289 MSYMBOL_TYPE (m) = mst_unknown;
1290 SYMBOL_SET_LANGUAGE (m, language_unknown, &objfile->objfile_obstack);
1294 /* Sort all the minimal symbols in OBJFILE. */
1297 msymbols_sort (struct objfile *objfile)
1299 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1300 sizeof (struct minimal_symbol), compare_minimal_symbols);
1301 build_minimal_symbol_hash_tables (objfile);
1304 /* Check if PC is in a shared library trampoline code stub.
1305 Return minimal symbol for the trampoline entry or NULL if PC is not
1306 in a trampoline code stub. */
1308 static struct minimal_symbol *
1309 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1311 struct obj_section *section = find_pc_section (pc);
1312 struct bound_minimal_symbol msymbol;
1314 if (section == NULL)
1316 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1318 if (msymbol.minsym != NULL
1319 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1320 return msymbol.minsym;
1324 /* If PC is in a shared library trampoline code stub, return the
1325 address of the `real' function belonging to the stub.
1326 Return 0 if PC is not in a trampoline code stub or if the real
1327 function is not found in the minimal symbol table.
1329 We may fail to find the right function if a function with the
1330 same name is defined in more than one shared library, but this
1331 is considered bad programming style. We could return 0 if we find
1332 a duplicate function in case this matters someday. */
1335 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1337 struct objfile *objfile;
1338 struct minimal_symbol *msymbol;
1339 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1341 if (tsymbol != NULL)
1343 ALL_MSYMBOLS (objfile, msymbol)
1345 if ((MSYMBOL_TYPE (msymbol) == mst_text
1346 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1347 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1348 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1349 return SYMBOL_VALUE_ADDRESS (msymbol);
1351 /* Also handle minimal symbols pointing to function descriptors. */
1352 if (MSYMBOL_TYPE (msymbol) == mst_data
1353 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1354 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1358 func = gdbarch_convert_from_func_ptr_addr
1359 (get_objfile_arch (objfile),
1360 SYMBOL_VALUE_ADDRESS (msymbol),
1363 /* Ignore data symbols that are not function descriptors. */
1364 if (func != SYMBOL_VALUE_ADDRESS (msymbol))