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. */
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];
142 /* Look through all the current minimal symbol tables and find the
143 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
144 the search to that objfile. If SFILE is non-NULL, the only file-scope
145 symbols considered will be from that source file (global symbols are
146 still preferred). Returns a pointer to the minimal symbol that
147 matches, or NULL if no match is found.
149 Note: One instance where there may be duplicate minimal symbols with
150 the same name is when the symbol tables for a shared library and the
151 symbol tables for an executable contain global symbols with the same
152 names (the dynamic linker deals with the duplication).
154 It's also possible to have minimal symbols with different mangled
155 names, but identical demangled names. For example, the GNU C++ v3
156 ABI requires the generation of two (or perhaps three) copies of
157 constructor functions --- "in-charge", "not-in-charge", and
158 "allocate" copies; destructors may be duplicated as well.
159 Obviously, there must be distinct mangled names for each of these,
160 but the demangled names are all the same: S::S or S::~S. */
162 static struct bound_minimal_symbol
163 lookup_minimal_symbol_internal (const char *name, const char *sfile,
164 struct objfile *objf)
166 struct objfile *objfile;
167 struct bound_minimal_symbol found_symbol = { NULL, NULL };
168 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
169 struct bound_minimal_symbol trampoline_symbol = { NULL, NULL };
171 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
172 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
174 int needtofreename = 0;
175 const char *modified_name;
178 sfile = lbasename (sfile);
180 /* For C++, canonicalize the input name. */
181 modified_name = name;
182 if (current_language->la_language == language_cplus)
184 char *cname = cp_canonicalize_string (name);
188 modified_name = cname;
193 for (objfile = object_files;
194 objfile != NULL && found_symbol.minsym == NULL;
195 objfile = objfile->next)
197 struct minimal_symbol *msymbol;
199 if (objf == NULL || objf == objfile
200 || objf == objfile->separate_debug_objfile_backlink)
202 /* Do two passes: the first over the ordinary hash table,
203 and the second over the demangled hash table. */
206 for (pass = 1; pass <= 2 && found_symbol.minsym == NULL; pass++)
208 /* Select hash list according to pass. */
210 msymbol = objfile->msymbol_hash[hash];
212 msymbol = objfile->msymbol_demangled_hash[dem_hash];
214 while (msymbol != NULL && found_symbol.minsym == NULL)
220 int (*cmp) (const char *, const char *);
222 cmp = (case_sensitivity == case_sensitive_on
223 ? strcmp : strcasecmp);
224 match = cmp (SYMBOL_LINKAGE_NAME (msymbol),
229 /* The function respects CASE_SENSITIVITY. */
230 match = SYMBOL_MATCHES_SEARCH_NAME (msymbol,
236 switch (MSYMBOL_TYPE (msymbol))
242 || filename_cmp (msymbol->filename, sfile) == 0)
244 found_file_symbol.minsym = msymbol;
245 found_file_symbol.objfile = objfile;
249 case mst_solib_trampoline:
251 /* If a trampoline symbol is found, we prefer to
252 keep looking for the *real* symbol. If the
253 actual symbol is not found, then we'll use the
255 if (trampoline_symbol.minsym == NULL)
257 trampoline_symbol.minsym = msymbol;
258 trampoline_symbol.objfile = objfile;
264 found_symbol.minsym = msymbol;
265 found_symbol.objfile = objfile;
270 /* Find the next symbol on the hash chain. */
272 msymbol = msymbol->hash_next;
274 msymbol = msymbol->demangled_hash_next;
281 xfree ((void *) modified_name);
283 /* External symbols are best. */
284 if (found_symbol.minsym != NULL)
287 /* File-local symbols are next best. */
288 if (found_file_symbol.minsym != NULL)
289 return found_file_symbol;
291 /* Symbols for shared library trampolines are next best. */
292 return trampoline_symbol;
297 struct minimal_symbol *
298 lookup_minimal_symbol (const char *name, const char *sfile,
299 struct objfile *objf)
301 struct bound_minimal_symbol bms = lookup_minimal_symbol_internal (name,
310 struct bound_minimal_symbol
311 lookup_bound_minimal_symbol (const char *name)
313 return lookup_minimal_symbol_internal (name, NULL, NULL);
319 iterate_over_minimal_symbols (struct objfile *objf, const char *name,
320 void (*callback) (struct minimal_symbol *,
325 struct minimal_symbol *iter;
326 int (*cmp) (const char *, const char *);
328 /* The first pass is over the ordinary hash table. */
329 hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
330 iter = objf->msymbol_hash[hash];
331 cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);
334 if (cmp (SYMBOL_LINKAGE_NAME (iter), name) == 0)
335 (*callback) (iter, user_data);
336 iter = iter->hash_next;
339 /* The second pass is over the demangled table. */
340 hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
341 iter = objf->msymbol_demangled_hash[hash];
344 if (SYMBOL_MATCHES_SEARCH_NAME (iter, name))
345 (*callback) (iter, user_data);
346 iter = iter->demangled_hash_next;
352 struct minimal_symbol *
353 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
355 struct objfile *objfile;
356 struct minimal_symbol *msymbol;
357 struct minimal_symbol *found_symbol = NULL;
358 struct minimal_symbol *found_file_symbol = NULL;
360 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
362 for (objfile = object_files;
363 objfile != NULL && found_symbol == NULL;
364 objfile = objfile->next)
366 if (objf == NULL || objf == objfile
367 || objf == objfile->separate_debug_objfile_backlink)
369 for (msymbol = objfile->msymbol_hash[hash];
370 msymbol != NULL && found_symbol == NULL;
371 msymbol = msymbol->hash_next)
373 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
374 (MSYMBOL_TYPE (msymbol) == mst_text
375 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
376 || MSYMBOL_TYPE (msymbol) == mst_file_text))
378 switch (MSYMBOL_TYPE (msymbol))
381 found_file_symbol = msymbol;
384 found_symbol = msymbol;
391 /* External symbols are best. */
395 /* File-local symbols are next best. */
396 if (found_file_symbol)
397 return found_file_symbol;
404 struct minimal_symbol *
405 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
406 struct objfile *objf)
408 struct objfile *objfile;
409 struct minimal_symbol *msymbol;
411 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
413 for (objfile = object_files;
415 objfile = objfile->next)
417 if (objf == NULL || objf == objfile
418 || objf == objfile->separate_debug_objfile_backlink)
420 for (msymbol = objfile->msymbol_hash[hash];
422 msymbol = msymbol->hash_next)
424 if (SYMBOL_VALUE_ADDRESS (msymbol) == pc
425 && strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0)
436 struct minimal_symbol *
437 lookup_minimal_symbol_solib_trampoline (const char *name,
438 struct objfile *objf)
440 struct objfile *objfile;
441 struct minimal_symbol *msymbol;
442 struct minimal_symbol *found_symbol = NULL;
444 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
446 for (objfile = object_files;
447 objfile != NULL && found_symbol == NULL;
448 objfile = objfile->next)
450 if (objf == NULL || objf == objfile
451 || objf == objfile->separate_debug_objfile_backlink)
453 for (msymbol = objfile->msymbol_hash[hash];
454 msymbol != NULL && found_symbol == NULL;
455 msymbol = msymbol->hash_next)
457 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
458 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
467 /* Search through the minimal symbol table for each objfile and find
468 the symbol whose address is the largest address that is still less
469 than or equal to PC, and matches SECTION (which is not NULL).
470 Returns a pointer to the minimal symbol if such a symbol is found,
471 or NULL if PC is not in a suitable range.
472 Note that we need to look through ALL the minimal symbol tables
473 before deciding on the symbol that comes closest to the specified PC.
474 This is because objfiles can overlap, for example objfile A has .text
475 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
478 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
479 there are text and trampoline symbols at the same address.
480 Otherwise prefer mst_text symbols. */
482 static struct bound_minimal_symbol
483 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc,
484 struct obj_section *section,
490 struct objfile *objfile;
491 struct minimal_symbol *msymbol;
492 struct minimal_symbol *best_symbol = NULL;
493 struct objfile *best_objfile = NULL;
494 struct bound_minimal_symbol result;
495 enum minimal_symbol_type want_type, other_type;
497 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
498 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
500 /* We can not require the symbol found to be in section, because
501 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
502 symbol - but find_pc_section won't return an absolute section and
503 hence the code below would skip over absolute symbols. We can
504 still take advantage of the call to find_pc_section, though - the
505 object file still must match. In case we have separate debug
506 files, search both the file and its separate debug file. There's
507 no telling which one will have the minimal symbols. */
509 gdb_assert (section != NULL);
511 for (objfile = section->objfile;
513 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
515 /* If this objfile has a minimal symbol table, go search it using
516 a binary search. Note that a minimal symbol table always consists
517 of at least two symbols, a "real" symbol and the terminating
518 "null symbol". If there are no real symbols, then there is no
519 minimal symbol table at all. */
521 if (objfile->minimal_symbol_count > 0)
523 int best_zero_sized = -1;
525 msymbol = objfile->msymbols;
527 hi = objfile->minimal_symbol_count - 1;
529 /* This code assumes that the minimal symbols are sorted by
530 ascending address values. If the pc value is greater than or
531 equal to the first symbol's address, then some symbol in this
532 minimal symbol table is a suitable candidate for being the
533 "best" symbol. This includes the last real symbol, for cases
534 where the pc value is larger than any address in this vector.
536 By iterating until the address associated with the current
537 hi index (the endpoint of the test interval) is less than
538 or equal to the desired pc value, we accomplish two things:
539 (1) the case where the pc value is larger than any minimal
540 symbol address is trivially solved, (2) the address associated
541 with the hi index is always the one we want when the interation
542 terminates. In essence, we are iterating the test interval
543 down until the pc value is pushed out of it from the high end.
545 Warning: this code is trickier than it would appear at first. */
547 /* Should also require that pc is <= end of objfile. FIXME! */
548 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
550 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
552 /* pc is still strictly less than highest address. */
553 /* Note "new" will always be >= lo. */
555 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
566 /* If we have multiple symbols at the same address, we want
567 hi to point to the last one. That way we can find the
568 right symbol if it has an index greater than hi. */
569 while (hi < objfile->minimal_symbol_count - 1
570 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
571 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
574 /* Skip various undesirable symbols. */
577 /* Skip any absolute symbols. This is apparently
578 what adb and dbx do, and is needed for the CM-5.
579 There are two known possible problems: (1) on
580 ELF, apparently end, edata, etc. are absolute.
581 Not sure ignoring them here is a big deal, but if
582 we want to use them, the fix would go in
583 elfread.c. (2) I think shared library entry
584 points on the NeXT are absolute. If we want
585 special handling for this it probably should be
586 triggered by a special mst_abs_or_lib or some
589 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
595 /* If SECTION was specified, skip any symbol from
598 /* Some types of debug info, such as COFF,
599 don't fill the bfd_section member, so don't
600 throw away symbols on those platforms. */
601 && SYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
602 && (!matching_obj_sections
603 (SYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
610 /* If we are looking for a trampoline and this is a
611 text symbol, or the other way around, check the
612 preceding symbol too. If they are otherwise
613 identical prefer that one. */
615 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
616 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
617 && (MSYMBOL_SIZE (&msymbol[hi])
618 == MSYMBOL_SIZE (&msymbol[hi - 1]))
619 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
620 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
621 && (SYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
622 == SYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
628 /* If the minimal symbol has a zero size, save it
629 but keep scanning backwards looking for one with
630 a non-zero size. A zero size may mean that the
631 symbol isn't an object or function (e.g. a
632 label), or it may just mean that the size was not
634 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
635 && best_zero_sized == -1)
637 best_zero_sized = hi;
642 /* If we are past the end of the current symbol, try
643 the previous symbol if it has a larger overlapping
644 size. This happens on i686-pc-linux-gnu with glibc;
645 the nocancel variants of system calls are inside
646 the cancellable variants, but both have sizes. */
648 && MSYMBOL_SIZE (&msymbol[hi]) != 0
649 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
650 + MSYMBOL_SIZE (&msymbol[hi]))
651 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
652 + MSYMBOL_SIZE (&msymbol[hi - 1])))
658 /* Otherwise, this symbol must be as good as we're going
663 /* If HI has a zero size, and best_zero_sized is set,
664 then we had two or more zero-sized symbols; prefer
665 the first one we found (which may have a higher
666 address). Also, if we ran off the end, be sure
668 if (best_zero_sized != -1
669 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
670 hi = best_zero_sized;
672 /* If the minimal symbol has a non-zero size, and this
673 PC appears to be outside the symbol's contents, then
674 refuse to use this symbol. If we found a zero-sized
675 symbol with an address greater than this symbol's,
676 use that instead. We assume that if symbols have
677 specified sizes, they do not overlap. */
680 && MSYMBOL_SIZE (&msymbol[hi]) != 0
681 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
682 + MSYMBOL_SIZE (&msymbol[hi])))
684 if (best_zero_sized != -1)
685 hi = best_zero_sized;
687 /* Go on to the next object file. */
691 /* The minimal symbol indexed by hi now is the best one in this
692 objfile's minimal symbol table. See if it is the best one
696 && ((best_symbol == NULL) ||
697 (SYMBOL_VALUE_ADDRESS (best_symbol) <
698 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
700 best_symbol = &msymbol[hi];
701 best_objfile = objfile;
707 result.minsym = best_symbol;
708 result.objfile = best_objfile;
712 struct bound_minimal_symbol
713 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
717 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
718 force the section but that (well unless you're doing overlay
719 debugging) always returns NULL making the call somewhat useless. */
720 section = find_pc_section (pc);
723 struct bound_minimal_symbol result;
725 memset (&result, 0, sizeof (result));
729 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
734 struct bound_minimal_symbol
735 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
737 struct obj_section *section = find_pc_section (pc);
741 struct bound_minimal_symbol result;
743 memset (&result, 0, sizeof (result));
746 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
749 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
752 in_gnu_ifunc_stub (CORE_ADDR pc)
754 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
756 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
759 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
762 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
764 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
765 "the ELF support compiled in."),
766 paddress (gdbarch, pc));
769 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
772 stub_gnu_ifunc_resolve_name (const char *function_name,
773 CORE_ADDR *function_address_p)
775 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
776 "the ELF support compiled in."),
780 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
783 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
785 internal_error (__FILE__, __LINE__,
786 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
789 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
792 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
794 internal_error (__FILE__, __LINE__,
795 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
798 /* See elf_gnu_ifunc_fns for its real implementation. */
800 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
802 stub_gnu_ifunc_resolve_addr,
803 stub_gnu_ifunc_resolve_name,
804 stub_gnu_ifunc_resolver_stop,
805 stub_gnu_ifunc_resolver_return_stop,
808 /* A placeholder for &elf_gnu_ifunc_fns. */
810 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
814 struct bound_minimal_symbol
815 lookup_minimal_symbol_and_objfile (const char *name)
817 struct bound_minimal_symbol result;
818 struct objfile *objfile;
819 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
821 ALL_OBJFILES (objfile)
823 struct minimal_symbol *msym;
825 for (msym = objfile->msymbol_hash[hash];
827 msym = msym->hash_next)
829 if (strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
831 result.minsym = msym;
832 result.objfile = objfile;
838 memset (&result, 0, sizeof (result));
843 /* Return leading symbol character for a BFD. If BFD is NULL,
844 return the leading symbol character from the main objfile. */
847 get_symbol_leading_char (bfd *abfd)
850 return bfd_get_symbol_leading_char (abfd);
851 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
852 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
859 init_minimal_symbol_collection (void)
863 /* Note that presetting msym_bunch_index to BUNCH_SIZE causes the
864 first call to save a minimal symbol to allocate the memory for
866 msym_bunch_index = BUNCH_SIZE;
872 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
873 enum minimal_symbol_type ms_type,
874 struct objfile *objfile)
881 case mst_text_gnu_ifunc:
883 case mst_solib_trampoline:
884 section = SECT_OFF_TEXT (objfile);
888 section = SECT_OFF_DATA (objfile);
892 section = SECT_OFF_BSS (objfile);
898 prim_record_minimal_symbol_and_info (name, address, ms_type,
904 struct minimal_symbol *
905 prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
907 enum minimal_symbol_type ms_type,
909 struct objfile *objfile)
911 struct obj_section *obj_section;
912 struct msym_bunch *new;
913 struct minimal_symbol *msymbol;
915 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
916 the minimal symbols, because if there is also another symbol
917 at the same address (e.g. the first function of the file),
918 lookup_minimal_symbol_by_pc would have no way of getting the
920 if (ms_type == mst_file_text && name[0] == 'g'
921 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
922 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
925 /* It's safe to strip the leading char here once, since the name
926 is also stored stripped in the minimal symbol table. */
927 if (name[0] == get_symbol_leading_char (objfile->obfd))
933 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
936 if (msym_bunch_index == BUNCH_SIZE)
938 new = XCNEW (struct msym_bunch);
939 msym_bunch_index = 0;
940 new->next = msym_bunch;
943 msymbol = &msym_bunch->contents[msym_bunch_index];
944 SYMBOL_SET_LANGUAGE (msymbol, language_auto, &objfile->objfile_obstack);
945 SYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, objfile);
947 SYMBOL_VALUE_ADDRESS (msymbol) = address;
948 SYMBOL_SECTION (msymbol) = section;
950 MSYMBOL_TYPE (msymbol) = ms_type;
951 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
952 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
953 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
954 as it would also set the has_size flag. */
957 /* The hash pointers must be cleared! If they're not,
958 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
959 msymbol->hash_next = NULL;
960 msymbol->demangled_hash_next = NULL;
964 OBJSTAT (objfile, n_minsyms++);
970 struct minimal_symbol *
971 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
972 enum minimal_symbol_type ms_type,
974 struct objfile *objfile)
976 return prim_record_minimal_symbol_full (name, strlen (name), 1,
981 /* Compare two minimal symbols by address and return a signed result based
982 on unsigned comparisons, so that we sort into unsigned numeric order.
983 Within groups with the same address, sort by name. */
986 compare_minimal_symbols (const void *fn1p, const void *fn2p)
988 const struct minimal_symbol *fn1;
989 const struct minimal_symbol *fn2;
991 fn1 = (const struct minimal_symbol *) fn1p;
992 fn2 = (const struct minimal_symbol *) fn2p;
994 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
996 return (-1); /* addr 1 is less than addr 2. */
998 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
1000 return (1); /* addr 1 is greater than addr 2. */
1003 /* addrs are equal: sort by name */
1005 const char *name1 = SYMBOL_LINKAGE_NAME (fn1);
1006 const char *name2 = SYMBOL_LINKAGE_NAME (fn2);
1008 if (name1 && name2) /* both have names */
1009 return strcmp (name1, name2);
1011 return 1; /* fn1 has no name, so it is "less". */
1012 else if (name1) /* fn2 has no name, so it is "less". */
1015 return (0); /* Neither has a name, so they're equal. */
1019 /* Discard the currently collected minimal symbols, if any. If we wish
1020 to save them for later use, we must have already copied them somewhere
1021 else before calling this function.
1023 FIXME: We could allocate the minimal symbol bunches on their own
1024 obstack and then simply blow the obstack away when we are done with
1025 it. Is it worth the extra trouble though? */
1028 do_discard_minimal_symbols_cleanup (void *arg)
1030 struct msym_bunch *next;
1032 while (msym_bunch != NULL)
1034 next = msym_bunch->next;
1040 /* See minsyms.h. */
1043 make_cleanup_discard_minimal_symbols (void)
1045 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
1050 /* Compact duplicate entries out of a minimal symbol table by walking
1051 through the table and compacting out entries with duplicate addresses
1052 and matching names. Return the number of entries remaining.
1054 On entry, the table resides between msymbol[0] and msymbol[mcount].
1055 On exit, it resides between msymbol[0] and msymbol[result_count].
1057 When files contain multiple sources of symbol information, it is
1058 possible for the minimal symbol table to contain many duplicate entries.
1059 As an example, SVR4 systems use ELF formatted object files, which
1060 usually contain at least two different types of symbol tables (a
1061 standard ELF one and a smaller dynamic linking table), as well as
1062 DWARF debugging information for files compiled with -g.
1064 Without compacting, the minimal symbol table for gdb itself contains
1065 over a 1000 duplicates, about a third of the total table size. Aside
1066 from the potential trap of not noticing that two successive entries
1067 identify the same location, this duplication impacts the time required
1068 to linearly scan the table, which is done in a number of places. So we
1069 just do one linear scan here and toss out the duplicates.
1071 Note that we are not concerned here about recovering the space that
1072 is potentially freed up, because the strings themselves are allocated
1073 on the objfile_obstack, and will get automatically freed when the symbol
1074 table is freed. The caller can free up the unused minimal symbols at
1075 the end of the compacted region if their allocation strategy allows it.
1077 Also note we only go up to the next to last entry within the loop
1078 and then copy the last entry explicitly after the loop terminates.
1080 Since the different sources of information for each symbol may
1081 have different levels of "completeness", we may have duplicates
1082 that have one entry with type "mst_unknown" and the other with a
1083 known type. So if the one we are leaving alone has type mst_unknown,
1084 overwrite its type with the type from the one we are compacting out. */
1087 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1088 struct objfile *objfile)
1090 struct minimal_symbol *copyfrom;
1091 struct minimal_symbol *copyto;
1095 copyfrom = copyto = msymbol;
1096 while (copyfrom < msymbol + mcount - 1)
1098 if (SYMBOL_VALUE_ADDRESS (copyfrom)
1099 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
1100 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
1101 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1103 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1105 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1110 *copyto++ = *copyfrom++;
1112 *copyto++ = *copyfrom++;
1113 mcount = copyto - msymbol;
1118 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1119 after compacting or sorting the table since the entries move around
1120 thus causing the internal minimal_symbol pointers to become jumbled. */
1123 build_minimal_symbol_hash_tables (struct objfile *objfile)
1126 struct minimal_symbol *msym;
1128 /* Clear the hash tables. */
1129 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1131 objfile->msymbol_hash[i] = 0;
1132 objfile->msymbol_demangled_hash[i] = 0;
1135 /* Now, (re)insert the actual entries. */
1136 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
1140 msym->hash_next = 0;
1141 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
1143 msym->demangled_hash_next = 0;
1144 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
1145 add_minsym_to_demangled_hash_table (msym,
1146 objfile->msymbol_demangled_hash);
1150 /* Add the minimal symbols in the existing bunches to the objfile's official
1151 minimal symbol table. In most cases there is no minimal symbol table yet
1152 for this objfile, and the existing bunches are used to create one. Once
1153 in a while (for shared libraries for example), we add symbols (e.g. common
1154 symbols) to an existing objfile.
1156 Because of the way minimal symbols are collected, we generally have no way
1157 of knowing what source language applies to any particular minimal symbol.
1158 Specifically, we have no way of knowing if the minimal symbol comes from a
1159 C++ compilation unit or not. So for the sake of supporting cached
1160 demangled C++ names, we have no choice but to try and demangle each new one
1161 that comes in. If the demangling succeeds, then we assume it is a C++
1162 symbol and set the symbol's language and demangled name fields
1163 appropriately. Note that in order to avoid unnecessary demanglings, and
1164 allocating obstack space that subsequently can't be freed for the demangled
1165 names, we mark all newly added symbols with language_auto. After
1166 compaction of the minimal symbols, we go back and scan the entire minimal
1167 symbol table looking for these new symbols. For each new symbol we attempt
1168 to demangle it, and if successful, record it as a language_cplus symbol
1169 and cache the demangled form on the symbol obstack. Symbols which don't
1170 demangle are marked as language_unknown symbols, which inhibits future
1171 attempts to demangle them if we later add more minimal symbols. */
1174 install_minimal_symbols (struct objfile *objfile)
1178 struct msym_bunch *bunch;
1179 struct minimal_symbol *msymbols;
1184 if (symtab_create_debug)
1186 fprintf_unfiltered (gdb_stdlog,
1187 "Installing %d minimal symbols of objfile %s.\n",
1188 msym_count, objfile_name (objfile));
1191 /* Allocate enough space in the obstack, into which we will gather the
1192 bunches of new and existing minimal symbols, sort them, and then
1193 compact out the duplicate entries. Once we have a final table,
1194 we will give back the excess space. */
1196 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1197 obstack_blank (&objfile->objfile_obstack,
1198 alloc_count * sizeof (struct minimal_symbol));
1199 msymbols = (struct minimal_symbol *)
1200 obstack_base (&objfile->objfile_obstack);
1202 /* Copy in the existing minimal symbols, if there are any. */
1204 if (objfile->minimal_symbol_count)
1205 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1206 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1208 /* Walk through the list of minimal symbol bunches, adding each symbol
1209 to the new contiguous array of symbols. Note that we start with the
1210 current, possibly partially filled bunch (thus we use the current
1211 msym_bunch_index for the first bunch we copy over), and thereafter
1212 each bunch is full. */
1214 mcount = objfile->minimal_symbol_count;
1216 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1218 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1219 msymbols[mcount] = bunch->contents[bindex];
1220 msym_bunch_index = BUNCH_SIZE;
1223 /* Sort the minimal symbols by address. */
1225 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1226 compare_minimal_symbols);
1228 /* Compact out any duplicates, and free up whatever space we are
1231 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1233 obstack_blank (&objfile->objfile_obstack,
1234 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1235 msymbols = (struct minimal_symbol *)
1236 obstack_finish (&objfile->objfile_obstack);
1238 /* We also terminate the minimal symbol table with a "null symbol",
1239 which is *not* included in the size of the table. This makes it
1240 easier to find the end of the table when we are handed a pointer
1241 to some symbol in the middle of it. Zero out the fields in the
1242 "null symbol" allocated at the end of the array. Note that the
1243 symbol count does *not* include this null symbol, which is why it
1244 is indexed by mcount and not mcount-1. */
1246 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1248 /* Attach the minimal symbol table to the specified objfile.
1249 The strings themselves are also located in the objfile_obstack
1252 objfile->minimal_symbol_count = mcount;
1253 objfile->msymbols = msymbols;
1255 /* Now build the hash tables; we can't do this incrementally
1256 at an earlier point since we weren't finished with the obstack
1257 yet. (And if the msymbol obstack gets moved, all the internal
1258 pointers to other msymbols need to be adjusted.) */
1259 build_minimal_symbol_hash_tables (objfile);
1263 /* See minsyms.h. */
1266 terminate_minimal_symbol_table (struct objfile *objfile)
1268 if (! objfile->msymbols)
1269 objfile->msymbols = ((struct minimal_symbol *)
1270 obstack_alloc (&objfile->objfile_obstack,
1271 sizeof (objfile->msymbols[0])));
1274 struct minimal_symbol *m
1275 = &objfile->msymbols[objfile->minimal_symbol_count];
1277 memset (m, 0, sizeof (*m));
1278 /* Don't rely on these enumeration values being 0's. */
1279 MSYMBOL_TYPE (m) = mst_unknown;
1280 SYMBOL_SET_LANGUAGE (m, language_unknown, &objfile->objfile_obstack);
1284 /* Sort all the minimal symbols in OBJFILE. */
1287 msymbols_sort (struct objfile *objfile)
1289 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1290 sizeof (struct minimal_symbol), compare_minimal_symbols);
1291 build_minimal_symbol_hash_tables (objfile);
1294 /* Check if PC is in a shared library trampoline code stub.
1295 Return minimal symbol for the trampoline entry or NULL if PC is not
1296 in a trampoline code stub. */
1298 static struct minimal_symbol *
1299 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1301 struct obj_section *section = find_pc_section (pc);
1302 struct bound_minimal_symbol msymbol;
1304 if (section == NULL)
1306 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1308 if (msymbol.minsym != NULL
1309 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1310 return msymbol.minsym;
1314 /* If PC is in a shared library trampoline code stub, return the
1315 address of the `real' function belonging to the stub.
1316 Return 0 if PC is not in a trampoline code stub or if the real
1317 function is not found in the minimal symbol table.
1319 We may fail to find the right function if a function with the
1320 same name is defined in more than one shared library, but this
1321 is considered bad programming style. We could return 0 if we find
1322 a duplicate function in case this matters someday. */
1325 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1327 struct objfile *objfile;
1328 struct minimal_symbol *msymbol;
1329 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1331 if (tsymbol != NULL)
1333 ALL_MSYMBOLS (objfile, msymbol)
1335 if ((MSYMBOL_TYPE (msymbol) == mst_text
1336 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1337 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1338 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1339 return SYMBOL_VALUE_ADDRESS (msymbol);
1341 /* Also handle minimal symbols pointing to function descriptors. */
1342 if (MSYMBOL_TYPE (msymbol) == mst_data
1343 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1344 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1348 func = gdbarch_convert_from_func_ptr_addr
1349 (get_objfile_arch (objfile),
1350 SYMBOL_VALUE_ADDRESS (msymbol),
1353 /* Ignore data symbols that are not function descriptors. */
1354 if (func != SYMBOL_VALUE_ADDRESS (msymbol))