1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2017 Free Software Foundation, Inc.
3 Contributed by Cygnus Support, using pieces from other GDB modules.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 /* This file contains support routines for creating, manipulating, and
22 destroying minimal symbol tables.
24 Minimal symbol tables are used to hold some very basic information about
25 all defined global symbols (text, data, bss, abs, etc). The only two
26 required pieces of information are the symbol's name and the address
27 associated with that symbol.
29 In many cases, even if a file was compiled with no special options for
30 debugging at all, as long as was not stripped it will contain sufficient
31 information to build useful minimal symbol tables using this structure.
33 Even when a file contains enough debugging information to build a full
34 symbol table, these minimal symbols are still useful for quickly mapping
35 between names and addresses, and vice versa. They are also sometimes used
36 to figure out what full symbol table entries need to be read in. */
43 #include "filenames.h"
50 #include "cp-support.h"
52 #include "cli/cli-utils.h"
55 #include "safe-ctype.h"
60 msymbol_is_function (struct objfile *objfile, minimal_symbol *minsym,
61 CORE_ADDR *func_address_p)
63 CORE_ADDR msym_addr = MSYMBOL_VALUE_ADDRESS (objfile, minsym);
67 case mst_slot_got_plt:
74 struct gdbarch *gdbarch = get_objfile_arch (objfile);
75 CORE_ADDR pc = gdbarch_convert_from_func_ptr_addr (gdbarch, msym_addr,
79 if (func_address_p != NULL)
86 if (func_address_p != NULL)
87 *func_address_p = msym_addr;
92 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
93 At the end, copy them all into one newly allocated location on an objfile's
94 per-BFD storage obstack. */
96 #define BUNCH_SIZE 127
100 struct msym_bunch *next;
101 struct minimal_symbol contents[BUNCH_SIZE];
107 msymbol_hash_iw (const char *string)
109 unsigned int hash = 0;
111 while (*string && *string != '(')
113 string = skip_spaces (string);
114 if (*string && *string != '(')
116 hash = SYMBOL_HASH_NEXT (hash, *string);
126 msymbol_hash (const char *string)
128 unsigned int hash = 0;
130 for (; *string; ++string)
131 hash = SYMBOL_HASH_NEXT (hash, *string);
135 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
137 add_minsym_to_hash_table (struct minimal_symbol *sym,
138 struct minimal_symbol **table)
140 if (sym->hash_next == NULL)
143 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
145 sym->hash_next = table[hash];
150 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
153 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
154 struct objfile *objfile)
156 if (sym->demangled_hash_next == NULL)
158 unsigned int hash = search_name_hash (MSYMBOL_LANGUAGE (sym),
159 MSYMBOL_SEARCH_NAME (sym));
161 auto &vec = objfile->per_bfd->demangled_hash_languages;
162 auto it = std::lower_bound (vec.begin (), vec.end (),
163 MSYMBOL_LANGUAGE (sym));
164 if (it == vec.end () || *it != MSYMBOL_LANGUAGE (sym))
165 vec.insert (it, MSYMBOL_LANGUAGE (sym));
167 struct minimal_symbol **table
168 = objfile->per_bfd->msymbol_demangled_hash;
169 unsigned int hash_index = hash % MINIMAL_SYMBOL_HASH_SIZE;
170 sym->demangled_hash_next = table[hash_index];
171 table[hash_index] = sym;
175 /* Worker object for lookup_minimal_symbol. Stores temporary results
176 while walking the symbol tables. */
178 struct found_minimal_symbols
180 /* External symbols are best. */
181 bound_minimal_symbol external_symbol {};
183 /* File-local symbols are next best. */
184 bound_minimal_symbol file_symbol {};
186 /* Symbols for shared library trampolines are next best. */
187 bound_minimal_symbol trampoline_symbol {};
189 /* Called when a symbol name matches. Check if the minsym is a
190 better type than what we had already found, and record it in one
191 of the members fields if so. Returns true if we collected the
192 real symbol, in which case we can stop searching. */
193 bool maybe_collect (const char *sfile, objfile *objf,
194 minimal_symbol *msymbol);
197 /* See declaration above. */
200 found_minimal_symbols::maybe_collect (const char *sfile,
201 struct objfile *objfile,
202 minimal_symbol *msymbol)
204 switch (MSYMBOL_TYPE (msymbol))
210 || filename_cmp (msymbol->filename, sfile) == 0)
212 file_symbol.minsym = msymbol;
213 file_symbol.objfile = objfile;
217 case mst_solib_trampoline:
219 /* If a trampoline symbol is found, we prefer to keep
220 looking for the *real* symbol. If the actual symbol
221 is not found, then we'll use the trampoline
223 if (trampoline_symbol.minsym == NULL)
225 trampoline_symbol.minsym = msymbol;
226 trampoline_symbol.objfile = objfile;
232 external_symbol.minsym = msymbol;
233 external_symbol.objfile = objfile;
234 /* We have the real symbol. No use looking further. */
242 /* Walk the mangled name hash table, and pass each symbol whose name
243 matches LOOKUP_NAME according to NAMECMP to FOUND. */
246 lookup_minimal_symbol_mangled (const char *lookup_name,
248 struct objfile *objfile,
249 struct minimal_symbol **table,
251 int (*namecmp) (const char *, const char *),
252 found_minimal_symbols &found)
254 for (minimal_symbol *msymbol = table[hash];
256 msymbol = msymbol->hash_next)
258 const char *symbol_name = MSYMBOL_LINKAGE_NAME (msymbol);
260 if (namecmp (symbol_name, lookup_name) == 0
261 && found.maybe_collect (sfile, objfile, msymbol))
266 /* Walk the demangled name hash table, and pass each symbol whose name
267 matches LOOKUP_NAME according to MATCHER to FOUND. */
270 lookup_minimal_symbol_demangled (const lookup_name_info &lookup_name,
272 struct objfile *objfile,
273 struct minimal_symbol **table,
275 symbol_name_matcher_ftype *matcher,
276 found_minimal_symbols &found)
278 for (minimal_symbol *msymbol = table[hash];
280 msymbol = msymbol->demangled_hash_next)
282 const char *symbol_name = MSYMBOL_SEARCH_NAME (msymbol);
284 if (matcher (symbol_name, lookup_name, NULL)
285 && found.maybe_collect (sfile, objfile, msymbol))
290 /* Look through all the current minimal symbol tables and find the
291 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
292 the search to that objfile. If SFILE is non-NULL, the only file-scope
293 symbols considered will be from that source file (global symbols are
294 still preferred). Returns a pointer to the minimal symbol that
295 matches, or NULL if no match is found.
297 Note: One instance where there may be duplicate minimal symbols with
298 the same name is when the symbol tables for a shared library and the
299 symbol tables for an executable contain global symbols with the same
300 names (the dynamic linker deals with the duplication).
302 It's also possible to have minimal symbols with different mangled
303 names, but identical demangled names. For example, the GNU C++ v3
304 ABI requires the generation of two (or perhaps three) copies of
305 constructor functions --- "in-charge", "not-in-charge", and
306 "allocate" copies; destructors may be duplicated as well.
307 Obviously, there must be distinct mangled names for each of these,
308 but the demangled names are all the same: S::S or S::~S. */
310 struct bound_minimal_symbol
311 lookup_minimal_symbol (const char *name, const char *sfile,
312 struct objfile *objf)
314 struct objfile *objfile;
315 found_minimal_symbols found;
317 unsigned int mangled_hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
320 = (case_sensitivity == case_sensitive_on
325 sfile = lbasename (sfile);
327 lookup_name_info lookup_name (name, symbol_name_match_type::FULL);
329 for (objfile = object_files;
330 objfile != NULL && found.external_symbol.minsym == NULL;
331 objfile = objfile->next)
333 if (objf == NULL || objf == objfile
334 || objf == objfile->separate_debug_objfile_backlink)
336 if (symbol_lookup_debug)
338 fprintf_unfiltered (gdb_stdlog,
339 "lookup_minimal_symbol (%s, %s, %s)\n",
340 name, sfile != NULL ? sfile : "NULL",
341 objfile_debug_name (objfile));
344 /* Do two passes: the first over the ordinary hash table,
345 and the second over the demangled hash table. */
346 lookup_minimal_symbol_mangled (name, sfile, objfile,
347 objfile->per_bfd->msymbol_hash,
348 mangled_hash, mangled_cmp, found);
350 /* If not found, try the demangled hash table. */
351 if (found.external_symbol.minsym == NULL)
353 /* Once for each language in the demangled hash names
354 table (usually just zero or one languages). */
355 for (auto lang : objfile->per_bfd->demangled_hash_languages)
358 = (lookup_name.search_name_hash (lang)
359 % MINIMAL_SYMBOL_HASH_SIZE);
361 symbol_name_matcher_ftype *match
362 = language_get_symbol_name_matcher (language_def (lang),
364 struct minimal_symbol **msymbol_demangled_hash
365 = objfile->per_bfd->msymbol_demangled_hash;
367 lookup_minimal_symbol_demangled (lookup_name, sfile, objfile,
368 msymbol_demangled_hash,
371 if (found.external_symbol.minsym != NULL)
378 /* External symbols are best. */
379 if (found.external_symbol.minsym != NULL)
381 if (symbol_lookup_debug)
383 minimal_symbol *minsym = found.external_symbol.minsym;
385 fprintf_unfiltered (gdb_stdlog,
386 "lookup_minimal_symbol (...) = %s (external)\n",
387 host_address_to_string (minsym));
389 return found.external_symbol;
392 /* File-local symbols are next best. */
393 if (found.file_symbol.minsym != NULL)
395 if (symbol_lookup_debug)
397 minimal_symbol *minsym = found.file_symbol.minsym;
399 fprintf_unfiltered (gdb_stdlog,
400 "lookup_minimal_symbol (...) = %s (file-local)\n",
401 host_address_to_string (minsym));
403 return found.file_symbol;
406 /* Symbols for shared library trampolines are next best. */
407 if (found.trampoline_symbol.minsym != NULL)
409 if (symbol_lookup_debug)
411 minimal_symbol *minsym = found.trampoline_symbol.minsym;
413 fprintf_unfiltered (gdb_stdlog,
414 "lookup_minimal_symbol (...) = %s (trampoline)\n",
415 host_address_to_string (minsym));
418 return found.trampoline_symbol;
422 if (symbol_lookup_debug)
423 fprintf_unfiltered (gdb_stdlog, "lookup_minimal_symbol (...) = NULL\n");
429 struct bound_minimal_symbol
430 lookup_bound_minimal_symbol (const char *name)
432 return lookup_minimal_symbol (name, NULL, NULL);
435 /* See common/symbol.h. */
438 find_minimal_symbol_address (const char *name, CORE_ADDR *addr,
439 struct objfile *objfile)
441 struct bound_minimal_symbol sym
442 = lookup_minimal_symbol (name, NULL, objfile);
444 if (sym.minsym != NULL)
445 *addr = BMSYMBOL_VALUE_ADDRESS (sym);
447 return sym.minsym == NULL;
453 iterate_over_minimal_symbols (struct objfile *objf,
454 const lookup_name_info &lookup_name,
455 void (*callback) (struct minimal_symbol *,
460 /* The first pass is over the ordinary hash table. */
462 const char *name = lookup_name.name ().c_str ();
463 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
465 = (case_sensitivity == case_sensitive_on
469 for (minimal_symbol *iter = objf->per_bfd->msymbol_hash[hash];
471 iter = iter->hash_next)
473 if (mangled_cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
474 (*callback) (iter, user_data);
478 /* The second pass is over the demangled table. Once for each
479 language in the demangled hash names table (usually just zero or
481 for (auto lang : objf->per_bfd->demangled_hash_languages)
483 const language_defn *lang_def = language_def (lang);
484 symbol_name_matcher_ftype *name_match
485 = language_get_symbol_name_matcher (lang_def, lookup_name);
488 = lookup_name.search_name_hash (lang) % MINIMAL_SYMBOL_HASH_SIZE;
489 for (minimal_symbol *iter = objf->per_bfd->msymbol_demangled_hash[hash];
491 iter = iter->demangled_hash_next)
492 if (name_match (MSYMBOL_SEARCH_NAME (iter), lookup_name, NULL))
493 (*callback) (iter, user_data);
499 struct bound_minimal_symbol
500 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
502 struct objfile *objfile;
503 struct minimal_symbol *msymbol;
504 struct bound_minimal_symbol found_symbol = { NULL, NULL };
505 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
507 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
509 for (objfile = object_files;
510 objfile != NULL && found_symbol.minsym == NULL;
511 objfile = objfile->next)
513 if (objf == NULL || objf == objfile
514 || objf == objfile->separate_debug_objfile_backlink)
516 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
517 msymbol != NULL && found_symbol.minsym == NULL;
518 msymbol = msymbol->hash_next)
520 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
521 (MSYMBOL_TYPE (msymbol) == mst_text
522 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
523 || MSYMBOL_TYPE (msymbol) == mst_file_text))
525 switch (MSYMBOL_TYPE (msymbol))
528 found_file_symbol.minsym = msymbol;
529 found_file_symbol.objfile = objfile;
532 found_symbol.minsym = msymbol;
533 found_symbol.objfile = objfile;
540 /* External symbols are best. */
541 if (found_symbol.minsym)
544 /* File-local symbols are next best. */
545 return found_file_symbol;
550 struct minimal_symbol *
551 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
552 struct objfile *objf)
554 struct objfile *objfile;
555 struct minimal_symbol *msymbol;
557 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
559 for (objfile = object_files;
561 objfile = objfile->next)
563 if (objf == NULL || objf == objfile
564 || objf == objfile->separate_debug_objfile_backlink)
566 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
568 msymbol = msymbol->hash_next)
570 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
571 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
582 struct bound_minimal_symbol
583 lookup_minimal_symbol_solib_trampoline (const char *name,
584 struct objfile *objf)
586 struct objfile *objfile;
587 struct minimal_symbol *msymbol;
588 struct bound_minimal_symbol found_symbol = { NULL, NULL };
590 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
592 for (objfile = object_files;
594 objfile = objfile->next)
596 if (objf == NULL || objf == objfile
597 || objf == objfile->separate_debug_objfile_backlink)
599 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
601 msymbol = msymbol->hash_next)
603 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
604 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
606 found_symbol.objfile = objfile;
607 found_symbol.minsym = msymbol;
617 /* A helper function that makes *PC section-relative. This searches
618 the sections of OBJFILE and if *PC is in a section, it subtracts
619 the section offset and returns true. Otherwise it returns
623 frob_address (struct objfile *objfile, CORE_ADDR *pc)
625 struct obj_section *iter;
627 ALL_OBJFILE_OSECTIONS (objfile, iter)
629 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
631 *pc -= obj_section_offset (iter);
639 /* Search through the minimal symbol table for each objfile and find
640 the symbol whose address is the largest address that is still less
641 than or equal to PC, and matches SECTION (which is not NULL).
642 Returns a pointer to the minimal symbol if such a symbol is found,
643 or NULL if PC is not in a suitable range.
644 Note that we need to look through ALL the minimal symbol tables
645 before deciding on the symbol that comes closest to the specified PC.
646 This is because objfiles can overlap, for example objfile A has .text
647 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
650 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
651 there are text and trampoline symbols at the same address.
652 Otherwise prefer mst_text symbols. */
654 static struct bound_minimal_symbol
655 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc_in,
656 struct obj_section *section,
662 struct objfile *objfile;
663 struct minimal_symbol *msymbol;
664 struct minimal_symbol *best_symbol = NULL;
665 struct objfile *best_objfile = NULL;
666 struct bound_minimal_symbol result;
667 enum minimal_symbol_type want_type, other_type;
669 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
670 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
672 /* We can not require the symbol found to be in section, because
673 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
674 symbol - but find_pc_section won't return an absolute section and
675 hence the code below would skip over absolute symbols. We can
676 still take advantage of the call to find_pc_section, though - the
677 object file still must match. In case we have separate debug
678 files, search both the file and its separate debug file. There's
679 no telling which one will have the minimal symbols. */
681 gdb_assert (section != NULL);
683 for (objfile = section->objfile;
685 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
687 CORE_ADDR pc = pc_in;
689 /* If this objfile has a minimal symbol table, go search it using
690 a binary search. Note that a minimal symbol table always consists
691 of at least two symbols, a "real" symbol and the terminating
692 "null symbol". If there are no real symbols, then there is no
693 minimal symbol table at all. */
695 if (objfile->per_bfd->minimal_symbol_count > 0)
697 int best_zero_sized = -1;
699 msymbol = objfile->per_bfd->msymbols;
701 hi = objfile->per_bfd->minimal_symbol_count - 1;
703 /* This code assumes that the minimal symbols are sorted by
704 ascending address values. If the pc value is greater than or
705 equal to the first symbol's address, then some symbol in this
706 minimal symbol table is a suitable candidate for being the
707 "best" symbol. This includes the last real symbol, for cases
708 where the pc value is larger than any address in this vector.
710 By iterating until the address associated with the current
711 hi index (the endpoint of the test interval) is less than
712 or equal to the desired pc value, we accomplish two things:
713 (1) the case where the pc value is larger than any minimal
714 symbol address is trivially solved, (2) the address associated
715 with the hi index is always the one we want when the interation
716 terminates. In essence, we are iterating the test interval
717 down until the pc value is pushed out of it from the high end.
719 Warning: this code is trickier than it would appear at first. */
721 if (frob_address (objfile, &pc)
722 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
724 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
726 /* pc is still strictly less than highest address. */
727 /* Note "new" will always be >= lo. */
728 newobj = (lo + hi) / 2;
729 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
740 /* If we have multiple symbols at the same address, we want
741 hi to point to the last one. That way we can find the
742 right symbol if it has an index greater than hi. */
743 while (hi < objfile->per_bfd->minimal_symbol_count - 1
744 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
745 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
748 /* Skip various undesirable symbols. */
751 /* Skip any absolute symbols. This is apparently
752 what adb and dbx do, and is needed for the CM-5.
753 There are two known possible problems: (1) on
754 ELF, apparently end, edata, etc. are absolute.
755 Not sure ignoring them here is a big deal, but if
756 we want to use them, the fix would go in
757 elfread.c. (2) I think shared library entry
758 points on the NeXT are absolute. If we want
759 special handling for this it probably should be
760 triggered by a special mst_abs_or_lib or some
763 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
769 /* If SECTION was specified, skip any symbol from
772 /* Some types of debug info, such as COFF,
773 don't fill the bfd_section member, so don't
774 throw away symbols on those platforms. */
775 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
776 && (!matching_obj_sections
777 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
784 /* If we are looking for a trampoline and this is a
785 text symbol, or the other way around, check the
786 preceding symbol too. If they are otherwise
787 identical prefer that one. */
789 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
790 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
791 && (MSYMBOL_SIZE (&msymbol[hi])
792 == MSYMBOL_SIZE (&msymbol[hi - 1]))
793 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
794 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
795 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
796 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
802 /* If the minimal symbol has a zero size, save it
803 but keep scanning backwards looking for one with
804 a non-zero size. A zero size may mean that the
805 symbol isn't an object or function (e.g. a
806 label), or it may just mean that the size was not
808 if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
810 if (best_zero_sized == -1)
811 best_zero_sized = hi;
816 /* If we are past the end of the current symbol, try
817 the previous symbol if it has a larger overlapping
818 size. This happens on i686-pc-linux-gnu with glibc;
819 the nocancel variants of system calls are inside
820 the cancellable variants, but both have sizes. */
822 && MSYMBOL_SIZE (&msymbol[hi]) != 0
823 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
824 + MSYMBOL_SIZE (&msymbol[hi]))
825 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
826 + MSYMBOL_SIZE (&msymbol[hi - 1])))
832 /* Otherwise, this symbol must be as good as we're going
837 /* If HI has a zero size, and best_zero_sized is set,
838 then we had two or more zero-sized symbols; prefer
839 the first one we found (which may have a higher
840 address). Also, if we ran off the end, be sure
842 if (best_zero_sized != -1
843 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
844 hi = best_zero_sized;
846 /* If the minimal symbol has a non-zero size, and this
847 PC appears to be outside the symbol's contents, then
848 refuse to use this symbol. If we found a zero-sized
849 symbol with an address greater than this symbol's,
850 use that instead. We assume that if symbols have
851 specified sizes, they do not overlap. */
854 && MSYMBOL_SIZE (&msymbol[hi]) != 0
855 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
856 + MSYMBOL_SIZE (&msymbol[hi])))
858 if (best_zero_sized != -1)
859 hi = best_zero_sized;
861 /* Go on to the next object file. */
865 /* The minimal symbol indexed by hi now is the best one in this
866 objfile's minimal symbol table. See if it is the best one
870 && ((best_symbol == NULL) ||
871 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
872 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
874 best_symbol = &msymbol[hi];
875 best_objfile = objfile;
881 result.minsym = best_symbol;
882 result.objfile = best_objfile;
886 struct bound_minimal_symbol
887 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
891 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
892 force the section but that (well unless you're doing overlay
893 debugging) always returns NULL making the call somewhat useless. */
894 section = find_pc_section (pc);
897 struct bound_minimal_symbol result;
899 memset (&result, 0, sizeof (result));
903 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
908 struct bound_minimal_symbol
909 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
911 struct obj_section *section = find_pc_section (pc);
915 struct bound_minimal_symbol result;
917 memset (&result, 0, sizeof (result));
920 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
923 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
926 in_gnu_ifunc_stub (CORE_ADDR pc)
928 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
930 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
933 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
936 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
938 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
939 "the ELF support compiled in."),
940 paddress (gdbarch, pc));
943 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
946 stub_gnu_ifunc_resolve_name (const char *function_name,
947 CORE_ADDR *function_address_p)
949 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
950 "the ELF support compiled in."),
954 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
957 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
959 internal_error (__FILE__, __LINE__,
960 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
963 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
966 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
968 internal_error (__FILE__, __LINE__,
969 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
972 /* See elf_gnu_ifunc_fns for its real implementation. */
974 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
976 stub_gnu_ifunc_resolve_addr,
977 stub_gnu_ifunc_resolve_name,
978 stub_gnu_ifunc_resolver_stop,
979 stub_gnu_ifunc_resolver_return_stop,
982 /* A placeholder for &elf_gnu_ifunc_fns. */
984 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
988 struct bound_minimal_symbol
989 lookup_minimal_symbol_and_objfile (const char *name)
991 struct bound_minimal_symbol result;
992 struct objfile *objfile;
993 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
995 ALL_OBJFILES (objfile)
997 struct minimal_symbol *msym;
999 for (msym = objfile->per_bfd->msymbol_hash[hash];
1001 msym = msym->hash_next)
1003 if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
1005 result.minsym = msym;
1006 result.objfile = objfile;
1012 memset (&result, 0, sizeof (result));
1017 /* Return leading symbol character for a BFD. If BFD is NULL,
1018 return the leading symbol character from the main objfile. */
1021 get_symbol_leading_char (bfd *abfd)
1024 return bfd_get_symbol_leading_char (abfd);
1025 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
1026 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
1030 /* See minsyms.h. */
1032 minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj)
1034 m_msym_bunch (NULL),
1035 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1036 first call to save a minimal symbol to allocate the memory for
1038 m_msym_bunch_index (BUNCH_SIZE),
1043 /* Discard the currently collected minimal symbols, if any. If we wish
1044 to save them for later use, we must have already copied them somewhere
1045 else before calling this function.
1047 FIXME: We could allocate the minimal symbol bunches on their own
1048 obstack and then simply blow the obstack away when we are done with
1049 it. Is it worth the extra trouble though? */
1051 minimal_symbol_reader::~minimal_symbol_reader ()
1053 struct msym_bunch *next;
1055 while (m_msym_bunch != NULL)
1057 next = m_msym_bunch->next;
1058 xfree (m_msym_bunch);
1059 m_msym_bunch = next;
1063 /* See minsyms.h. */
1066 minimal_symbol_reader::record (const char *name, CORE_ADDR address,
1067 enum minimal_symbol_type ms_type)
1074 case mst_text_gnu_ifunc:
1076 case mst_solib_trampoline:
1077 section = SECT_OFF_TEXT (m_objfile);
1081 section = SECT_OFF_DATA (m_objfile);
1085 section = SECT_OFF_BSS (m_objfile);
1091 record_with_info (name, address, ms_type, section);
1094 /* See minsyms.h. */
1096 struct minimal_symbol *
1097 minimal_symbol_reader::record_full (const char *name, int name_len,
1098 bool copy_name, CORE_ADDR address,
1099 enum minimal_symbol_type ms_type,
1102 struct msym_bunch *newobj;
1103 struct minimal_symbol *msymbol;
1105 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1106 the minimal symbols, because if there is also another symbol
1107 at the same address (e.g. the first function of the file),
1108 lookup_minimal_symbol_by_pc would have no way of getting the
1110 if (ms_type == mst_file_text && name[0] == 'g'
1111 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
1112 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
1115 /* It's safe to strip the leading char here once, since the name
1116 is also stored stripped in the minimal symbol table. */
1117 if (name[0] == get_symbol_leading_char (m_objfile->obfd))
1123 if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
1126 if (m_msym_bunch_index == BUNCH_SIZE)
1128 newobj = XCNEW (struct msym_bunch);
1129 m_msym_bunch_index = 0;
1130 newobj->next = m_msym_bunch;
1131 m_msym_bunch = newobj;
1133 msymbol = &m_msym_bunch->contents[m_msym_bunch_index];
1134 MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
1135 &m_objfile->per_bfd->storage_obstack);
1136 MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, m_objfile);
1138 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1139 MSYMBOL_SECTION (msymbol) = section;
1141 MSYMBOL_TYPE (msymbol) = ms_type;
1142 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
1143 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
1144 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
1145 as it would also set the has_size flag. */
1148 /* The hash pointers must be cleared! If they're not,
1149 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
1150 msymbol->hash_next = NULL;
1151 msymbol->demangled_hash_next = NULL;
1153 /* If we already read minimal symbols for this objfile, then don't
1154 ever allocate a new one. */
1155 if (!m_objfile->per_bfd->minsyms_read)
1157 m_msym_bunch_index++;
1158 m_objfile->per_bfd->n_minsyms++;
1164 /* Compare two minimal symbols by address and return a signed result based
1165 on unsigned comparisons, so that we sort into unsigned numeric order.
1166 Within groups with the same address, sort by name. */
1169 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1171 const struct minimal_symbol *fn1;
1172 const struct minimal_symbol *fn2;
1174 fn1 = (const struct minimal_symbol *) fn1p;
1175 fn2 = (const struct minimal_symbol *) fn2p;
1177 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1179 return (-1); /* addr 1 is less than addr 2. */
1181 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1183 return (1); /* addr 1 is greater than addr 2. */
1186 /* addrs are equal: sort by name */
1188 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1189 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1191 if (name1 && name2) /* both have names */
1192 return strcmp (name1, name2);
1194 return 1; /* fn1 has no name, so it is "less". */
1195 else if (name1) /* fn2 has no name, so it is "less". */
1198 return (0); /* Neither has a name, so they're equal. */
1202 /* Compact duplicate entries out of a minimal symbol table by walking
1203 through the table and compacting out entries with duplicate addresses
1204 and matching names. Return the number of entries remaining.
1206 On entry, the table resides between msymbol[0] and msymbol[mcount].
1207 On exit, it resides between msymbol[0] and msymbol[result_count].
1209 When files contain multiple sources of symbol information, it is
1210 possible for the minimal symbol table to contain many duplicate entries.
1211 As an example, SVR4 systems use ELF formatted object files, which
1212 usually contain at least two different types of symbol tables (a
1213 standard ELF one and a smaller dynamic linking table), as well as
1214 DWARF debugging information for files compiled with -g.
1216 Without compacting, the minimal symbol table for gdb itself contains
1217 over a 1000 duplicates, about a third of the total table size. Aside
1218 from the potential trap of not noticing that two successive entries
1219 identify the same location, this duplication impacts the time required
1220 to linearly scan the table, which is done in a number of places. So we
1221 just do one linear scan here and toss out the duplicates.
1223 Note that we are not concerned here about recovering the space that
1224 is potentially freed up, because the strings themselves are allocated
1225 on the storage_obstack, and will get automatically freed when the symbol
1226 table is freed. The caller can free up the unused minimal symbols at
1227 the end of the compacted region if their allocation strategy allows it.
1229 Also note we only go up to the next to last entry within the loop
1230 and then copy the last entry explicitly after the loop terminates.
1232 Since the different sources of information for each symbol may
1233 have different levels of "completeness", we may have duplicates
1234 that have one entry with type "mst_unknown" and the other with a
1235 known type. So if the one we are leaving alone has type mst_unknown,
1236 overwrite its type with the type from the one we are compacting out. */
1239 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1240 struct objfile *objfile)
1242 struct minimal_symbol *copyfrom;
1243 struct minimal_symbol *copyto;
1247 copyfrom = copyto = msymbol;
1248 while (copyfrom < msymbol + mcount - 1)
1250 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1251 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1252 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1253 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1254 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1256 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1258 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1263 *copyto++ = *copyfrom++;
1265 *copyto++ = *copyfrom++;
1266 mcount = copyto - msymbol;
1271 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1272 after compacting or sorting the table since the entries move around
1273 thus causing the internal minimal_symbol pointers to become jumbled. */
1276 build_minimal_symbol_hash_tables (struct objfile *objfile)
1279 struct minimal_symbol *msym;
1281 /* Clear the hash tables. */
1282 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1284 objfile->per_bfd->msymbol_hash[i] = 0;
1285 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1288 /* Now, (re)insert the actual entries. */
1289 for ((i = objfile->per_bfd->minimal_symbol_count,
1290 msym = objfile->per_bfd->msymbols);
1294 msym->hash_next = 0;
1295 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1297 msym->demangled_hash_next = 0;
1298 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1299 add_minsym_to_demangled_hash_table (msym, objfile);
1303 /* Add the minimal symbols in the existing bunches to the objfile's official
1304 minimal symbol table. In most cases there is no minimal symbol table yet
1305 for this objfile, and the existing bunches are used to create one. Once
1306 in a while (for shared libraries for example), we add symbols (e.g. common
1307 symbols) to an existing objfile.
1309 Because of the way minimal symbols are collected, we generally have no way
1310 of knowing what source language applies to any particular minimal symbol.
1311 Specifically, we have no way of knowing if the minimal symbol comes from a
1312 C++ compilation unit or not. So for the sake of supporting cached
1313 demangled C++ names, we have no choice but to try and demangle each new one
1314 that comes in. If the demangling succeeds, then we assume it is a C++
1315 symbol and set the symbol's language and demangled name fields
1316 appropriately. Note that in order to avoid unnecessary demanglings, and
1317 allocating obstack space that subsequently can't be freed for the demangled
1318 names, we mark all newly added symbols with language_auto. After
1319 compaction of the minimal symbols, we go back and scan the entire minimal
1320 symbol table looking for these new symbols. For each new symbol we attempt
1321 to demangle it, and if successful, record it as a language_cplus symbol
1322 and cache the demangled form on the symbol obstack. Symbols which don't
1323 demangle are marked as language_unknown symbols, which inhibits future
1324 attempts to demangle them if we later add more minimal symbols. */
1327 minimal_symbol_reader::install ()
1331 struct msym_bunch *bunch;
1332 struct minimal_symbol *msymbols;
1335 if (m_objfile->per_bfd->minsyms_read)
1338 if (m_msym_count > 0)
1340 if (symtab_create_debug)
1342 fprintf_unfiltered (gdb_stdlog,
1343 "Installing %d minimal symbols of objfile %s.\n",
1344 m_msym_count, objfile_name (m_objfile));
1347 /* Allocate enough space in the obstack, into which we will gather the
1348 bunches of new and existing minimal symbols, sort them, and then
1349 compact out the duplicate entries. Once we have a final table,
1350 we will give back the excess space. */
1352 alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count + 1;
1353 obstack_blank (&m_objfile->per_bfd->storage_obstack,
1354 alloc_count * sizeof (struct minimal_symbol));
1355 msymbols = (struct minimal_symbol *)
1356 obstack_base (&m_objfile->per_bfd->storage_obstack);
1358 /* Copy in the existing minimal symbols, if there are any. */
1360 if (m_objfile->per_bfd->minimal_symbol_count)
1361 memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols,
1362 m_objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol));
1364 /* Walk through the list of minimal symbol bunches, adding each symbol
1365 to the new contiguous array of symbols. Note that we start with the
1366 current, possibly partially filled bunch (thus we use the current
1367 msym_bunch_index for the first bunch we copy over), and thereafter
1368 each bunch is full. */
1370 mcount = m_objfile->per_bfd->minimal_symbol_count;
1372 for (bunch = m_msym_bunch; bunch != NULL; bunch = bunch->next)
1374 for (bindex = 0; bindex < m_msym_bunch_index; bindex++, mcount++)
1375 msymbols[mcount] = bunch->contents[bindex];
1376 m_msym_bunch_index = BUNCH_SIZE;
1379 /* Sort the minimal symbols by address. */
1381 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1382 compare_minimal_symbols);
1384 /* Compact out any duplicates, and free up whatever space we are
1387 mcount = compact_minimal_symbols (msymbols, mcount, m_objfile);
1389 obstack_blank_fast (&m_objfile->per_bfd->storage_obstack,
1390 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1391 msymbols = (struct minimal_symbol *)
1392 obstack_finish (&m_objfile->per_bfd->storage_obstack);
1394 /* We also terminate the minimal symbol table with a "null symbol",
1395 which is *not* included in the size of the table. This makes it
1396 easier to find the end of the table when we are handed a pointer
1397 to some symbol in the middle of it. Zero out the fields in the
1398 "null symbol" allocated at the end of the array. Note that the
1399 symbol count does *not* include this null symbol, which is why it
1400 is indexed by mcount and not mcount-1. */
1402 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1404 /* Attach the minimal symbol table to the specified objfile.
1405 The strings themselves are also located in the storage_obstack
1408 m_objfile->per_bfd->minimal_symbol_count = mcount;
1409 m_objfile->per_bfd->msymbols = msymbols;
1411 /* Now build the hash tables; we can't do this incrementally
1412 at an earlier point since we weren't finished with the obstack
1413 yet. (And if the msymbol obstack gets moved, all the internal
1414 pointers to other msymbols need to be adjusted.) */
1415 build_minimal_symbol_hash_tables (m_objfile);
1419 /* See minsyms.h. */
1422 terminate_minimal_symbol_table (struct objfile *objfile)
1424 if (! objfile->per_bfd->msymbols)
1425 objfile->per_bfd->msymbols
1426 = ((struct minimal_symbol *)
1427 obstack_alloc (&objfile->per_bfd->storage_obstack,
1428 sizeof (struct minimal_symbol)));
1431 struct minimal_symbol *m
1432 = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1434 memset (m, 0, sizeof (*m));
1435 /* Don't rely on these enumeration values being 0's. */
1436 MSYMBOL_TYPE (m) = mst_unknown;
1437 MSYMBOL_SET_LANGUAGE (m, language_unknown,
1438 &objfile->per_bfd->storage_obstack);
1442 /* Check if PC is in a shared library trampoline code stub.
1443 Return minimal symbol for the trampoline entry or NULL if PC is not
1444 in a trampoline code stub. */
1446 static struct minimal_symbol *
1447 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1449 struct obj_section *section = find_pc_section (pc);
1450 struct bound_minimal_symbol msymbol;
1452 if (section == NULL)
1454 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1456 if (msymbol.minsym != NULL
1457 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1458 return msymbol.minsym;
1462 /* If PC is in a shared library trampoline code stub, return the
1463 address of the `real' function belonging to the stub.
1464 Return 0 if PC is not in a trampoline code stub or if the real
1465 function is not found in the minimal symbol table.
1467 We may fail to find the right function if a function with the
1468 same name is defined in more than one shared library, but this
1469 is considered bad programming style. We could return 0 if we find
1470 a duplicate function in case this matters someday. */
1473 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1475 struct objfile *objfile;
1476 struct minimal_symbol *msymbol;
1477 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1479 if (tsymbol != NULL)
1481 ALL_MSYMBOLS (objfile, msymbol)
1483 if ((MSYMBOL_TYPE (msymbol) == mst_text
1484 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1485 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1486 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1487 return MSYMBOL_VALUE_ADDRESS (objfile, msymbol);
1489 /* Also handle minimal symbols pointing to function descriptors. */
1490 if (MSYMBOL_TYPE (msymbol) == mst_data
1491 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1492 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1496 func = gdbarch_convert_from_func_ptr_addr
1497 (get_objfile_arch (objfile),
1498 MSYMBOL_VALUE_ADDRESS (objfile, msymbol),
1501 /* Ignore data symbols that are not function descriptors. */
1502 if (func != MSYMBOL_VALUE_ADDRESS (objfile, msymbol))
1510 /* See minsyms.h. */
1513 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1517 struct obj_section *obj_section;
1519 struct minimal_symbol *msymbol;
1521 gdb_assert (minsym.minsym != NULL);
1523 /* If the minimal symbol has a size, use it. Otherwise use the
1524 lesser of the next minimal symbol in the same section, or the end
1525 of the section, as the end of the function. */
1527 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1528 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1530 /* Step over other symbols at this same address, and symbols in
1531 other sections, to find the next symbol in this section with a
1532 different address. */
1534 msymbol = minsym.minsym;
1535 section = MSYMBOL_SECTION (msymbol);
1536 for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1538 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1539 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1540 && MSYMBOL_SECTION (msymbol + i) == section)
1544 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1545 if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1546 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1547 < obj_section_endaddr (obj_section)))
1548 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
1550 /* We got the start address from the last msymbol in the objfile.
1551 So the end address is the end of the section. */
1552 result = obj_section_endaddr (obj_section);