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 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 enum minimal_symbol_type want_type, other_type;
490 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
491 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
493 /* We can not require the symbol found to be in section, because
494 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
495 symbol - but find_pc_section won't return an absolute section and
496 hence the code below would skip over absolute symbols. We can
497 still take advantage of the call to find_pc_section, though - the
498 object file still must match. In case we have separate debug
499 files, search both the file and its separate debug file. There's
500 no telling which one will have the minimal symbols. */
502 gdb_assert (section != NULL);
504 for (objfile = section->objfile;
506 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
508 /* If this objfile has a minimal symbol table, go search it using
509 a binary search. Note that a minimal symbol table always consists
510 of at least two symbols, a "real" symbol and the terminating
511 "null symbol". If there are no real symbols, then there is no
512 minimal symbol table at all. */
514 if (objfile->minimal_symbol_count > 0)
516 int best_zero_sized = -1;
518 msymbol = objfile->msymbols;
520 hi = objfile->minimal_symbol_count - 1;
522 /* This code assumes that the minimal symbols are sorted by
523 ascending address values. If the pc value is greater than or
524 equal to the first symbol's address, then some symbol in this
525 minimal symbol table is a suitable candidate for being the
526 "best" symbol. This includes the last real symbol, for cases
527 where the pc value is larger than any address in this vector.
529 By iterating until the address associated with the current
530 hi index (the endpoint of the test interval) is less than
531 or equal to the desired pc value, we accomplish two things:
532 (1) the case where the pc value is larger than any minimal
533 symbol address is trivially solved, (2) the address associated
534 with the hi index is always the one we want when the interation
535 terminates. In essence, we are iterating the test interval
536 down until the pc value is pushed out of it from the high end.
538 Warning: this code is trickier than it would appear at first. */
540 /* Should also require that pc is <= end of objfile. FIXME! */
541 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
543 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
545 /* pc is still strictly less than highest address. */
546 /* Note "new" will always be >= lo. */
548 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
559 /* If we have multiple symbols at the same address, we want
560 hi to point to the last one. That way we can find the
561 right symbol if it has an index greater than hi. */
562 while (hi < objfile->minimal_symbol_count - 1
563 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
564 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
567 /* Skip various undesirable symbols. */
570 /* Skip any absolute symbols. This is apparently
571 what adb and dbx do, and is needed for the CM-5.
572 There are two known possible problems: (1) on
573 ELF, apparently end, edata, etc. are absolute.
574 Not sure ignoring them here is a big deal, but if
575 we want to use them, the fix would go in
576 elfread.c. (2) I think shared library entry
577 points on the NeXT are absolute. If we want
578 special handling for this it probably should be
579 triggered by a special mst_abs_or_lib or some
582 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
588 /* If SECTION was specified, skip any symbol from
591 /* Some types of debug info, such as COFF,
592 don't fill the bfd_section member, so don't
593 throw away symbols on those platforms. */
594 && SYMBOL_OBJ_SECTION (&msymbol[hi]) != NULL
595 && (!matching_obj_sections
596 (SYMBOL_OBJ_SECTION (&msymbol[hi]), section)))
602 /* If we are looking for a trampoline and this is a
603 text symbol, or the other way around, check the
604 preceding symbol too. If they are otherwise
605 identical prefer that one. */
607 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
608 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
609 && (MSYMBOL_SIZE (&msymbol[hi])
610 == MSYMBOL_SIZE (&msymbol[hi - 1]))
611 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
612 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
613 && (SYMBOL_OBJ_SECTION (&msymbol[hi])
614 == SYMBOL_OBJ_SECTION (&msymbol[hi - 1])))
620 /* If the minimal symbol has a zero size, save it
621 but keep scanning backwards looking for one with
622 a non-zero size. A zero size may mean that the
623 symbol isn't an object or function (e.g. a
624 label), or it may just mean that the size was not
626 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
627 && best_zero_sized == -1)
629 best_zero_sized = hi;
634 /* If we are past the end of the current symbol, try
635 the previous symbol if it has a larger overlapping
636 size. This happens on i686-pc-linux-gnu with glibc;
637 the nocancel variants of system calls are inside
638 the cancellable variants, but both have sizes. */
640 && MSYMBOL_SIZE (&msymbol[hi]) != 0
641 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
642 + MSYMBOL_SIZE (&msymbol[hi]))
643 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
644 + MSYMBOL_SIZE (&msymbol[hi - 1])))
650 /* Otherwise, this symbol must be as good as we're going
655 /* If HI has a zero size, and best_zero_sized is set,
656 then we had two or more zero-sized symbols; prefer
657 the first one we found (which may have a higher
658 address). Also, if we ran off the end, be sure
660 if (best_zero_sized != -1
661 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
662 hi = best_zero_sized;
664 /* If the minimal symbol has a non-zero size, and this
665 PC appears to be outside the symbol's contents, then
666 refuse to use this symbol. If we found a zero-sized
667 symbol with an address greater than this symbol's,
668 use that instead. We assume that if symbols have
669 specified sizes, they do not overlap. */
672 && MSYMBOL_SIZE (&msymbol[hi]) != 0
673 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
674 + MSYMBOL_SIZE (&msymbol[hi])))
676 if (best_zero_sized != -1)
677 hi = best_zero_sized;
679 /* Go on to the next object file. */
683 /* The minimal symbol indexed by hi now is the best one in this
684 objfile's minimal symbol table. See if it is the best one
688 && ((best_symbol == NULL) ||
689 (SYMBOL_VALUE_ADDRESS (best_symbol) <
690 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
692 best_symbol = &msymbol[hi];
697 return (best_symbol);
700 struct minimal_symbol *
701 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
705 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
706 force the section but that (well unless you're doing overlay
707 debugging) always returns NULL making the call somewhat useless. */
708 section = find_pc_section (pc);
712 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
717 struct minimal_symbol *
718 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
720 return lookup_minimal_symbol_by_pc_section (pc, NULL);
723 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
726 in_gnu_ifunc_stub (CORE_ADDR pc)
728 struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (pc);
730 return msymbol && MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc;
733 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
736 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
738 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
739 "the ELF support compiled in."),
740 paddress (gdbarch, pc));
743 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
746 stub_gnu_ifunc_resolve_name (const char *function_name,
747 CORE_ADDR *function_address_p)
749 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
750 "the ELF support compiled in."),
754 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
757 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
759 internal_error (__FILE__, __LINE__,
760 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
763 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
766 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
768 internal_error (__FILE__, __LINE__,
769 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
772 /* See elf_gnu_ifunc_fns for its real implementation. */
774 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
776 stub_gnu_ifunc_resolve_addr,
777 stub_gnu_ifunc_resolve_name,
778 stub_gnu_ifunc_resolver_stop,
779 stub_gnu_ifunc_resolver_return_stop,
782 /* A placeholder for &elf_gnu_ifunc_fns. */
784 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
788 struct minimal_symbol *
789 lookup_minimal_symbol_and_objfile (const char *name,
790 struct objfile **objfile_p)
792 struct objfile *objfile;
793 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
795 ALL_OBJFILES (objfile)
797 struct minimal_symbol *msym;
799 for (msym = objfile->msymbol_hash[hash];
801 msym = msym->hash_next)
803 if (strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
805 *objfile_p = objfile;
815 /* Return leading symbol character for a BFD. If BFD is NULL,
816 return the leading symbol character from the main objfile. */
818 static int get_symbol_leading_char (bfd *);
821 get_symbol_leading_char (bfd *abfd)
824 return bfd_get_symbol_leading_char (abfd);
825 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
826 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
833 init_minimal_symbol_collection (void)
837 /* Note that presetting msym_bunch_index to BUNCH_SIZE causes the
838 first call to save a minimal symbol to allocate the memory for
840 msym_bunch_index = BUNCH_SIZE;
846 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
847 enum minimal_symbol_type ms_type,
848 struct objfile *objfile)
855 case mst_text_gnu_ifunc:
857 case mst_solib_trampoline:
858 section = SECT_OFF_TEXT (objfile);
862 section = SECT_OFF_DATA (objfile);
866 section = SECT_OFF_BSS (objfile);
872 prim_record_minimal_symbol_and_info (name, address, ms_type,
873 section, NULL, objfile);
878 struct minimal_symbol *
879 prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
881 enum minimal_symbol_type ms_type,
883 asection *bfd_section,
884 struct objfile *objfile)
886 struct obj_section *obj_section;
887 struct msym_bunch *new;
888 struct minimal_symbol *msymbol;
890 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
891 the minimal symbols, because if there is also another symbol
892 at the same address (e.g. the first function of the file),
893 lookup_minimal_symbol_by_pc would have no way of getting the
895 if (ms_type == mst_file_text && name[0] == 'g'
896 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
897 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
900 /* It's safe to strip the leading char here once, since the name
901 is also stored stripped in the minimal symbol table. */
902 if (name[0] == get_symbol_leading_char (objfile->obfd))
908 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
911 if (msym_bunch_index == BUNCH_SIZE)
913 new = XCALLOC (1, struct msym_bunch);
914 msym_bunch_index = 0;
915 new->next = msym_bunch;
918 msymbol = &msym_bunch->contents[msym_bunch_index];
919 SYMBOL_SET_LANGUAGE (msymbol, language_auto, &objfile->objfile_obstack);
920 SYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, objfile);
922 SYMBOL_VALUE_ADDRESS (msymbol) = address;
923 SYMBOL_SECTION (msymbol) = section;
924 SYMBOL_OBJ_SECTION (msymbol) = NULL;
926 /* Find obj_section corresponding to bfd_section. */
928 ALL_OBJFILE_OSECTIONS (objfile, obj_section)
930 if (obj_section->the_bfd_section == bfd_section)
932 SYMBOL_OBJ_SECTION (msymbol) = obj_section;
937 MSYMBOL_TYPE (msymbol) = ms_type;
938 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
939 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
940 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
941 as it would also set the has_size flag. */
944 /* The hash pointers must be cleared! If they're not,
945 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
946 msymbol->hash_next = NULL;
947 msymbol->demangled_hash_next = NULL;
951 OBJSTAT (objfile, n_minsyms++);
957 struct minimal_symbol *
958 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
959 enum minimal_symbol_type ms_type,
961 asection *bfd_section,
962 struct objfile *objfile)
964 return prim_record_minimal_symbol_full (name, strlen (name), 1,
965 address, ms_type, section,
966 bfd_section, objfile);
969 /* Compare two minimal symbols by address and return a signed result based
970 on unsigned comparisons, so that we sort into unsigned numeric order.
971 Within groups with the same address, sort by name. */
974 compare_minimal_symbols (const void *fn1p, const void *fn2p)
976 const struct minimal_symbol *fn1;
977 const struct minimal_symbol *fn2;
979 fn1 = (const struct minimal_symbol *) fn1p;
980 fn2 = (const struct minimal_symbol *) fn2p;
982 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
984 return (-1); /* addr 1 is less than addr 2. */
986 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
988 return (1); /* addr 1 is greater than addr 2. */
991 /* addrs are equal: sort by name */
993 const char *name1 = SYMBOL_LINKAGE_NAME (fn1);
994 const char *name2 = SYMBOL_LINKAGE_NAME (fn2);
996 if (name1 && name2) /* both have names */
997 return strcmp (name1, name2);
999 return 1; /* fn1 has no name, so it is "less". */
1000 else if (name1) /* fn2 has no name, so it is "less". */
1003 return (0); /* Neither has a name, so they're equal. */
1007 /* Discard the currently collected minimal symbols, if any. If we wish
1008 to save them for later use, we must have already copied them somewhere
1009 else before calling this function.
1011 FIXME: We could allocate the minimal symbol bunches on their own
1012 obstack and then simply blow the obstack away when we are done with
1013 it. Is it worth the extra trouble though? */
1016 do_discard_minimal_symbols_cleanup (void *arg)
1018 struct msym_bunch *next;
1020 while (msym_bunch != NULL)
1022 next = msym_bunch->next;
1028 /* See minsyms.h. */
1031 make_cleanup_discard_minimal_symbols (void)
1033 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
1038 /* Compact duplicate entries out of a minimal symbol table by walking
1039 through the table and compacting out entries with duplicate addresses
1040 and matching names. Return the number of entries remaining.
1042 On entry, the table resides between msymbol[0] and msymbol[mcount].
1043 On exit, it resides between msymbol[0] and msymbol[result_count].
1045 When files contain multiple sources of symbol information, it is
1046 possible for the minimal symbol table to contain many duplicate entries.
1047 As an example, SVR4 systems use ELF formatted object files, which
1048 usually contain at least two different types of symbol tables (a
1049 standard ELF one and a smaller dynamic linking table), as well as
1050 DWARF debugging information for files compiled with -g.
1052 Without compacting, the minimal symbol table for gdb itself contains
1053 over a 1000 duplicates, about a third of the total table size. Aside
1054 from the potential trap of not noticing that two successive entries
1055 identify the same location, this duplication impacts the time required
1056 to linearly scan the table, which is done in a number of places. So we
1057 just do one linear scan here and toss out the duplicates.
1059 Note that we are not concerned here about recovering the space that
1060 is potentially freed up, because the strings themselves are allocated
1061 on the objfile_obstack, and will get automatically freed when the symbol
1062 table is freed. The caller can free up the unused minimal symbols at
1063 the end of the compacted region if their allocation strategy allows it.
1065 Also note we only go up to the next to last entry within the loop
1066 and then copy the last entry explicitly after the loop terminates.
1068 Since the different sources of information for each symbol may
1069 have different levels of "completeness", we may have duplicates
1070 that have one entry with type "mst_unknown" and the other with a
1071 known type. So if the one we are leaving alone has type mst_unknown,
1072 overwrite its type with the type from the one we are compacting out. */
1075 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1076 struct objfile *objfile)
1078 struct minimal_symbol *copyfrom;
1079 struct minimal_symbol *copyto;
1083 copyfrom = copyto = msymbol;
1084 while (copyfrom < msymbol + mcount - 1)
1086 if (SYMBOL_VALUE_ADDRESS (copyfrom)
1087 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
1088 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
1089 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1091 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1093 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1098 *copyto++ = *copyfrom++;
1100 *copyto++ = *copyfrom++;
1101 mcount = copyto - msymbol;
1106 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1107 after compacting or sorting the table since the entries move around
1108 thus causing the internal minimal_symbol pointers to become jumbled. */
1111 build_minimal_symbol_hash_tables (struct objfile *objfile)
1114 struct minimal_symbol *msym;
1116 /* Clear the hash tables. */
1117 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1119 objfile->msymbol_hash[i] = 0;
1120 objfile->msymbol_demangled_hash[i] = 0;
1123 /* Now, (re)insert the actual entries. */
1124 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
1128 msym->hash_next = 0;
1129 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
1131 msym->demangled_hash_next = 0;
1132 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
1133 add_minsym_to_demangled_hash_table (msym,
1134 objfile->msymbol_demangled_hash);
1138 /* Add the minimal symbols in the existing bunches to the objfile's official
1139 minimal symbol table. In most cases there is no minimal symbol table yet
1140 for this objfile, and the existing bunches are used to create one. Once
1141 in a while (for shared libraries for example), we add symbols (e.g. common
1142 symbols) to an existing objfile.
1144 Because of the way minimal symbols are collected, we generally have no way
1145 of knowing what source language applies to any particular minimal symbol.
1146 Specifically, we have no way of knowing if the minimal symbol comes from a
1147 C++ compilation unit or not. So for the sake of supporting cached
1148 demangled C++ names, we have no choice but to try and demangle each new one
1149 that comes in. If the demangling succeeds, then we assume it is a C++
1150 symbol and set the symbol's language and demangled name fields
1151 appropriately. Note that in order to avoid unnecessary demanglings, and
1152 allocating obstack space that subsequently can't be freed for the demangled
1153 names, we mark all newly added symbols with language_auto. After
1154 compaction of the minimal symbols, we go back and scan the entire minimal
1155 symbol table looking for these new symbols. For each new symbol we attempt
1156 to demangle it, and if successful, record it as a language_cplus symbol
1157 and cache the demangled form on the symbol obstack. Symbols which don't
1158 demangle are marked as language_unknown symbols, which inhibits future
1159 attempts to demangle them if we later add more minimal symbols. */
1162 install_minimal_symbols (struct objfile *objfile)
1166 struct msym_bunch *bunch;
1167 struct minimal_symbol *msymbols;
1172 if (symtab_create_debug)
1174 fprintf_unfiltered (gdb_stdlog,
1175 "Installing %d minimal symbols of objfile %s.\n",
1176 msym_count, objfile->name);
1179 /* Allocate enough space in the obstack, into which we will gather the
1180 bunches of new and existing minimal symbols, sort them, and then
1181 compact out the duplicate entries. Once we have a final table,
1182 we will give back the excess space. */
1184 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1185 obstack_blank (&objfile->objfile_obstack,
1186 alloc_count * sizeof (struct minimal_symbol));
1187 msymbols = (struct minimal_symbol *)
1188 obstack_base (&objfile->objfile_obstack);
1190 /* Copy in the existing minimal symbols, if there are any. */
1192 if (objfile->minimal_symbol_count)
1193 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1194 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1196 /* Walk through the list of minimal symbol bunches, adding each symbol
1197 to the new contiguous array of symbols. Note that we start with the
1198 current, possibly partially filled bunch (thus we use the current
1199 msym_bunch_index for the first bunch we copy over), and thereafter
1200 each bunch is full. */
1202 mcount = objfile->minimal_symbol_count;
1204 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1206 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1207 msymbols[mcount] = bunch->contents[bindex];
1208 msym_bunch_index = BUNCH_SIZE;
1211 /* Sort the minimal symbols by address. */
1213 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1214 compare_minimal_symbols);
1216 /* Compact out any duplicates, and free up whatever space we are
1219 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1221 obstack_blank (&objfile->objfile_obstack,
1222 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1223 msymbols = (struct minimal_symbol *)
1224 obstack_finish (&objfile->objfile_obstack);
1226 /* We also terminate the minimal symbol table with a "null symbol",
1227 which is *not* included in the size of the table. This makes it
1228 easier to find the end of the table when we are handed a pointer
1229 to some symbol in the middle of it. Zero out the fields in the
1230 "null symbol" allocated at the end of the array. Note that the
1231 symbol count does *not* include this null symbol, which is why it
1232 is indexed by mcount and not mcount-1. */
1234 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1236 /* Attach the minimal symbol table to the specified objfile.
1237 The strings themselves are also located in the objfile_obstack
1240 objfile->minimal_symbol_count = mcount;
1241 objfile->msymbols = msymbols;
1243 /* Now build the hash tables; we can't do this incrementally
1244 at an earlier point since we weren't finished with the obstack
1245 yet. (And if the msymbol obstack gets moved, all the internal
1246 pointers to other msymbols need to be adjusted.) */
1247 build_minimal_symbol_hash_tables (objfile);
1251 /* See minsyms.h. */
1254 terminate_minimal_symbol_table (struct objfile *objfile)
1256 if (! objfile->msymbols)
1257 objfile->msymbols = ((struct minimal_symbol *)
1258 obstack_alloc (&objfile->objfile_obstack,
1259 sizeof (objfile->msymbols[0])));
1262 struct minimal_symbol *m
1263 = &objfile->msymbols[objfile->minimal_symbol_count];
1265 memset (m, 0, sizeof (*m));
1266 /* Don't rely on these enumeration values being 0's. */
1267 MSYMBOL_TYPE (m) = mst_unknown;
1268 SYMBOL_SET_LANGUAGE (m, language_unknown, &objfile->objfile_obstack);
1272 /* Sort all the minimal symbols in OBJFILE. */
1275 msymbols_sort (struct objfile *objfile)
1277 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1278 sizeof (struct minimal_symbol), compare_minimal_symbols);
1279 build_minimal_symbol_hash_tables (objfile);
1282 /* Check if PC is in a shared library trampoline code stub.
1283 Return minimal symbol for the trampoline entry or NULL if PC is not
1284 in a trampoline code stub. */
1286 static struct minimal_symbol *
1287 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1289 struct obj_section *section = find_pc_section (pc);
1290 struct minimal_symbol *msymbol;
1292 if (section == NULL)
1294 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1296 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
1301 /* If PC is in a shared library trampoline code stub, return the
1302 address of the `real' function belonging to the stub.
1303 Return 0 if PC is not in a trampoline code stub or if the real
1304 function is not found in the minimal symbol table.
1306 We may fail to find the right function if a function with the
1307 same name is defined in more than one shared library, but this
1308 is considered bad programming style. We could return 0 if we find
1309 a duplicate function in case this matters someday. */
1312 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1314 struct objfile *objfile;
1315 struct minimal_symbol *msymbol;
1316 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1318 if (tsymbol != NULL)
1320 ALL_MSYMBOLS (objfile, msymbol)
1322 if ((MSYMBOL_TYPE (msymbol) == mst_text
1323 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1324 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1325 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1326 return SYMBOL_VALUE_ADDRESS (msymbol);
1328 /* Also handle minimal symbols pointing to function descriptors. */
1329 if (MSYMBOL_TYPE (msymbol) == mst_data
1330 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1331 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1335 func = gdbarch_convert_from_func_ptr_addr
1336 (get_objfile_arch (objfile),
1337 SYMBOL_VALUE_ADDRESS (msymbol),
1340 /* Ignore data symbols that are not function descriptors. */
1341 if (func != SYMBOL_VALUE_ADDRESS (msymbol))