1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2019 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"
53 #include "common/symbol.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:
73 case mst_data_gnu_ifunc:
75 struct gdbarch *gdbarch = get_objfile_arch (objfile);
77 = gdbarch_convert_from_func_ptr_addr (gdbarch, msym_addr,
78 current_top_target ());
81 if (func_address_p != NULL)
88 if (func_address_p != NULL)
89 *func_address_p = msym_addr;
94 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
95 At the end, copy them all into one newly allocated array. */
97 #define BUNCH_SIZE 127
101 struct msym_bunch *next;
102 struct minimal_symbol contents[BUNCH_SIZE];
108 msymbol_hash_iw (const char *string)
110 unsigned int hash = 0;
112 while (*string && *string != '(')
114 string = skip_spaces (string);
115 if (*string && *string != '(')
117 hash = SYMBOL_HASH_NEXT (hash, *string);
127 msymbol_hash (const char *string)
129 unsigned int hash = 0;
131 for (; *string; ++string)
132 hash = SYMBOL_HASH_NEXT (hash, *string);
136 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
138 add_minsym_to_hash_table (struct minimal_symbol *sym,
139 struct minimal_symbol **table)
141 if (sym->hash_next == NULL)
144 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
146 sym->hash_next = table[hash];
151 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
154 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
155 struct objfile *objfile)
157 if (sym->demangled_hash_next == NULL)
159 unsigned int hash = search_name_hash (MSYMBOL_LANGUAGE (sym),
160 MSYMBOL_SEARCH_NAME (sym));
162 objfile->per_bfd->demangled_hash_languages.set (MSYMBOL_LANGUAGE (sym));
164 struct minimal_symbol **table
165 = objfile->per_bfd->msymbol_demangled_hash;
166 unsigned int hash_index = hash % MINIMAL_SYMBOL_HASH_SIZE;
167 sym->demangled_hash_next = table[hash_index];
168 table[hash_index] = sym;
172 /* Worker object for lookup_minimal_symbol. Stores temporary results
173 while walking the symbol tables. */
175 struct found_minimal_symbols
177 /* External symbols are best. */
178 bound_minimal_symbol external_symbol {};
180 /* File-local symbols are next best. */
181 bound_minimal_symbol file_symbol {};
183 /* Symbols for shared library trampolines are next best. */
184 bound_minimal_symbol trampoline_symbol {};
186 /* Called when a symbol name matches. Check if the minsym is a
187 better type than what we had already found, and record it in one
188 of the members fields if so. Returns true if we collected the
189 real symbol, in which case we can stop searching. */
190 bool maybe_collect (const char *sfile, objfile *objf,
191 minimal_symbol *msymbol);
194 /* See declaration above. */
197 found_minimal_symbols::maybe_collect (const char *sfile,
198 struct objfile *objfile,
199 minimal_symbol *msymbol)
201 switch (MSYMBOL_TYPE (msymbol))
207 || filename_cmp (msymbol->filename, sfile) == 0)
209 file_symbol.minsym = msymbol;
210 file_symbol.objfile = objfile;
214 case mst_solib_trampoline:
216 /* If a trampoline symbol is found, we prefer to keep
217 looking for the *real* symbol. If the actual symbol
218 is not found, then we'll use the trampoline
220 if (trampoline_symbol.minsym == NULL)
222 trampoline_symbol.minsym = msymbol;
223 trampoline_symbol.objfile = objfile;
229 external_symbol.minsym = msymbol;
230 external_symbol.objfile = objfile;
231 /* We have the real symbol. No use looking further. */
239 /* Walk the mangled name hash table, and pass each symbol whose name
240 matches LOOKUP_NAME according to NAMECMP to FOUND. */
243 lookup_minimal_symbol_mangled (const char *lookup_name,
245 struct objfile *objfile,
246 struct minimal_symbol **table,
248 int (*namecmp) (const char *, const char *),
249 found_minimal_symbols &found)
251 for (minimal_symbol *msymbol = table[hash];
253 msymbol = msymbol->hash_next)
255 const char *symbol_name = MSYMBOL_LINKAGE_NAME (msymbol);
257 if (namecmp (symbol_name, lookup_name) == 0
258 && found.maybe_collect (sfile, objfile, msymbol))
263 /* Walk the demangled name hash table, and pass each symbol whose name
264 matches LOOKUP_NAME according to MATCHER to FOUND. */
267 lookup_minimal_symbol_demangled (const lookup_name_info &lookup_name,
269 struct objfile *objfile,
270 struct minimal_symbol **table,
272 symbol_name_matcher_ftype *matcher,
273 found_minimal_symbols &found)
275 for (minimal_symbol *msymbol = table[hash];
277 msymbol = msymbol->demangled_hash_next)
279 const char *symbol_name = MSYMBOL_SEARCH_NAME (msymbol);
281 if (matcher (symbol_name, lookup_name, NULL)
282 && found.maybe_collect (sfile, objfile, msymbol))
287 /* Look through all the current minimal symbol tables and find the
288 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
289 the search to that objfile. If SFILE is non-NULL, the only file-scope
290 symbols considered will be from that source file (global symbols are
291 still preferred). Returns a pointer to the minimal symbol that
292 matches, or NULL if no match is found.
294 Note: One instance where there may be duplicate minimal symbols with
295 the same name is when the symbol tables for a shared library and the
296 symbol tables for an executable contain global symbols with the same
297 names (the dynamic linker deals with the duplication).
299 It's also possible to have minimal symbols with different mangled
300 names, but identical demangled names. For example, the GNU C++ v3
301 ABI requires the generation of two (or perhaps three) copies of
302 constructor functions --- "in-charge", "not-in-charge", and
303 "allocate" copies; destructors may be duplicated as well.
304 Obviously, there must be distinct mangled names for each of these,
305 but the demangled names are all the same: S::S or S::~S. */
307 struct bound_minimal_symbol
308 lookup_minimal_symbol (const char *name, const char *sfile,
309 struct objfile *objf)
311 struct objfile *objfile;
312 found_minimal_symbols found;
314 unsigned int mangled_hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
317 = (case_sensitivity == case_sensitive_on
322 sfile = lbasename (sfile);
324 lookup_name_info lookup_name (name, symbol_name_match_type::FULL);
326 for (objfile = object_files;
327 objfile != NULL && found.external_symbol.minsym == NULL;
328 objfile = objfile->next)
330 if (objf == NULL || objf == objfile
331 || objf == objfile->separate_debug_objfile_backlink)
333 if (symbol_lookup_debug)
335 fprintf_unfiltered (gdb_stdlog,
336 "lookup_minimal_symbol (%s, %s, %s)\n",
337 name, sfile != NULL ? sfile : "NULL",
338 objfile_debug_name (objfile));
341 /* Do two passes: the first over the ordinary hash table,
342 and the second over the demangled hash table. */
343 lookup_minimal_symbol_mangled (name, sfile, objfile,
344 objfile->per_bfd->msymbol_hash,
345 mangled_hash, mangled_cmp, found);
347 /* If not found, try the demangled hash table. */
348 if (found.external_symbol.minsym == NULL)
350 /* Once for each language in the demangled hash names
351 table (usually just zero or one languages). */
352 for (unsigned iter = 0; iter < nr_languages; ++iter)
354 if (!objfile->per_bfd->demangled_hash_languages.test (iter))
356 enum language lang = (enum language) iter;
359 = (lookup_name.search_name_hash (lang)
360 % MINIMAL_SYMBOL_HASH_SIZE);
362 symbol_name_matcher_ftype *match
363 = get_symbol_name_matcher (language_def (lang),
365 struct minimal_symbol **msymbol_demangled_hash
366 = objfile->per_bfd->msymbol_demangled_hash;
368 lookup_minimal_symbol_demangled (lookup_name, sfile, objfile,
369 msymbol_demangled_hash,
372 if (found.external_symbol.minsym != NULL)
379 /* External symbols are best. */
380 if (found.external_symbol.minsym != NULL)
382 if (symbol_lookup_debug)
384 minimal_symbol *minsym = found.external_symbol.minsym;
386 fprintf_unfiltered (gdb_stdlog,
387 "lookup_minimal_symbol (...) = %s (external)\n",
388 host_address_to_string (minsym));
390 return found.external_symbol;
393 /* File-local symbols are next best. */
394 if (found.file_symbol.minsym != NULL)
396 if (symbol_lookup_debug)
398 minimal_symbol *minsym = found.file_symbol.minsym;
400 fprintf_unfiltered (gdb_stdlog,
401 "lookup_minimal_symbol (...) = %s (file-local)\n",
402 host_address_to_string (minsym));
404 return found.file_symbol;
407 /* Symbols for shared library trampolines are next best. */
408 if (found.trampoline_symbol.minsym != NULL)
410 if (symbol_lookup_debug)
412 minimal_symbol *minsym = found.trampoline_symbol.minsym;
414 fprintf_unfiltered (gdb_stdlog,
415 "lookup_minimal_symbol (...) = %s (trampoline)\n",
416 host_address_to_string (minsym));
419 return found.trampoline_symbol;
423 if (symbol_lookup_debug)
424 fprintf_unfiltered (gdb_stdlog, "lookup_minimal_symbol (...) = NULL\n");
430 struct bound_minimal_symbol
431 lookup_bound_minimal_symbol (const char *name)
433 return lookup_minimal_symbol (name, NULL, NULL);
436 /* See common/symbol.h. */
439 find_minimal_symbol_address (const char *name, CORE_ADDR *addr,
440 struct objfile *objfile)
442 struct bound_minimal_symbol sym
443 = lookup_minimal_symbol (name, NULL, objfile);
445 if (sym.minsym != NULL)
446 *addr = BMSYMBOL_VALUE_ADDRESS (sym);
448 return sym.minsym == NULL;
451 /* Get the lookup name form best suitable for linkage name
455 linkage_name_str (const lookup_name_info &lookup_name)
457 /* Unlike most languages (including C++), Ada uses the
458 encoded/linkage name as the search name recorded in symbols. So
459 if debugging in Ada mode, prefer the Ada-encoded name. This also
460 makes Ada's verbatim match syntax ("<...>") work, because
461 "lookup_name.name()" includes the "<>"s, while
462 "lookup_name.ada().lookup_name()" is the encoded name with "<>"s
464 if (current_language->la_language == language_ada)
465 return lookup_name.ada ().lookup_name ().c_str ();
467 return lookup_name.name ().c_str ();
473 iterate_over_minimal_symbols
474 (struct objfile *objf, const lookup_name_info &lookup_name,
475 gdb::function_view<bool (struct minimal_symbol *)> callback)
477 /* The first pass is over the ordinary hash table. */
479 const char *name = linkage_name_str (lookup_name);
480 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
482 = (case_sensitivity == case_sensitive_on
486 for (minimal_symbol *iter = objf->per_bfd->msymbol_hash[hash];
488 iter = iter->hash_next)
490 if (mangled_cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
496 /* The second pass is over the demangled table. Once for each
497 language in the demangled hash names table (usually just zero or
499 for (unsigned liter = 0; liter < nr_languages; ++liter)
501 if (!objf->per_bfd->demangled_hash_languages.test (liter))
504 enum language lang = (enum language) liter;
505 const language_defn *lang_def = language_def (lang);
506 symbol_name_matcher_ftype *name_match
507 = get_symbol_name_matcher (lang_def, lookup_name);
510 = lookup_name.search_name_hash (lang) % MINIMAL_SYMBOL_HASH_SIZE;
511 for (minimal_symbol *iter = objf->per_bfd->msymbol_demangled_hash[hash];
513 iter = iter->demangled_hash_next)
514 if (name_match (MSYMBOL_SEARCH_NAME (iter), lookup_name, NULL))
522 struct bound_minimal_symbol
523 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
525 struct objfile *objfile;
526 struct minimal_symbol *msymbol;
527 struct bound_minimal_symbol found_symbol = { NULL, NULL };
528 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
530 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
532 for (objfile = object_files;
533 objfile != NULL && found_symbol.minsym == NULL;
534 objfile = objfile->next)
536 if (objf == NULL || objf == objfile
537 || objf == objfile->separate_debug_objfile_backlink)
539 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
540 msymbol != NULL && found_symbol.minsym == NULL;
541 msymbol = msymbol->hash_next)
543 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
544 (MSYMBOL_TYPE (msymbol) == mst_text
545 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
546 || MSYMBOL_TYPE (msymbol) == mst_file_text))
548 switch (MSYMBOL_TYPE (msymbol))
551 found_file_symbol.minsym = msymbol;
552 found_file_symbol.objfile = objfile;
555 found_symbol.minsym = msymbol;
556 found_symbol.objfile = objfile;
563 /* External symbols are best. */
564 if (found_symbol.minsym)
567 /* File-local symbols are next best. */
568 return found_file_symbol;
573 struct minimal_symbol *
574 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
575 struct objfile *objf)
577 struct objfile *objfile;
578 struct minimal_symbol *msymbol;
580 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
582 for (objfile = object_files;
584 objfile = objfile->next)
586 if (objf == NULL || objf == objfile
587 || objf == objfile->separate_debug_objfile_backlink)
589 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
591 msymbol = msymbol->hash_next)
593 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
594 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
605 struct bound_minimal_symbol
606 lookup_minimal_symbol_solib_trampoline (const char *name,
607 struct objfile *objf)
609 struct objfile *objfile;
610 struct minimal_symbol *msymbol;
611 struct bound_minimal_symbol found_symbol = { NULL, NULL };
613 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
615 for (objfile = object_files;
617 objfile = objfile->next)
619 if (objf == NULL || objf == objfile
620 || objf == objfile->separate_debug_objfile_backlink)
622 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
624 msymbol = msymbol->hash_next)
626 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
627 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
629 found_symbol.objfile = objfile;
630 found_symbol.minsym = msymbol;
640 /* A helper function that makes *PC section-relative. This searches
641 the sections of OBJFILE and if *PC is in a section, it subtracts
642 the section offset and returns true. Otherwise it returns
646 frob_address (struct objfile *objfile, CORE_ADDR *pc)
648 struct obj_section *iter;
650 ALL_OBJFILE_OSECTIONS (objfile, iter)
652 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
654 *pc -= obj_section_offset (iter);
662 /* Helper for lookup_minimal_symbol_by_pc_section. Convert a
663 lookup_msym_prefer to a minimal_symbol_type. */
665 static minimal_symbol_type
666 msym_prefer_to_msym_type (lookup_msym_prefer prefer)
670 case lookup_msym_prefer::TEXT:
672 case lookup_msym_prefer::TRAMPOLINE:
673 return mst_solib_trampoline;
674 case lookup_msym_prefer::GNU_IFUNC:
675 return mst_text_gnu_ifunc;
678 /* Assert here instead of in a default switch case above so that
679 -Wswitch warns if a new enumerator is added. */
680 gdb_assert_not_reached ("unhandled lookup_msym_prefer");
683 /* Search through the minimal symbol table for each objfile and find
684 the symbol whose address is the largest address that is still less
685 than or equal to PC, and matches SECTION (which is not NULL).
686 Returns a pointer to the minimal symbol if such a symbol is found,
687 or NULL if PC is not in a suitable range.
688 Note that we need to look through ALL the minimal symbol tables
689 before deciding on the symbol that comes closest to the specified PC.
690 This is because objfiles can overlap, for example objfile A has .text
691 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
694 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
695 there are text and trampoline symbols at the same address.
696 Otherwise prefer mst_text symbols. */
699 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *section,
700 lookup_msym_prefer prefer)
705 struct objfile *objfile;
706 struct minimal_symbol *msymbol;
707 struct minimal_symbol *best_symbol = NULL;
708 struct objfile *best_objfile = NULL;
709 struct bound_minimal_symbol result;
713 section = find_pc_section (pc_in);
718 minimal_symbol_type want_type = msym_prefer_to_msym_type (prefer);
720 /* We can not require the symbol found to be in section, because
721 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
722 symbol - but find_pc_section won't return an absolute section and
723 hence the code below would skip over absolute symbols. We can
724 still take advantage of the call to find_pc_section, though - the
725 object file still must match. In case we have separate debug
726 files, search both the file and its separate debug file. There's
727 no telling which one will have the minimal symbols. */
729 gdb_assert (section != NULL);
731 for (objfile = section->objfile;
733 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
735 CORE_ADDR pc = pc_in;
737 /* If this objfile has a minimal symbol table, go search it
738 using a binary search. */
740 if (objfile->per_bfd->minimal_symbol_count > 0)
742 int best_zero_sized = -1;
744 msymbol = objfile->per_bfd->msymbols.get ();
746 hi = objfile->per_bfd->minimal_symbol_count - 1;
748 /* This code assumes that the minimal symbols are sorted by
749 ascending address values. If the pc value is greater than or
750 equal to the first symbol's address, then some symbol in this
751 minimal symbol table is a suitable candidate for being the
752 "best" symbol. This includes the last real symbol, for cases
753 where the pc value is larger than any address in this vector.
755 By iterating until the address associated with the current
756 hi index (the endpoint of the test interval) is less than
757 or equal to the desired pc value, we accomplish two things:
758 (1) the case where the pc value is larger than any minimal
759 symbol address is trivially solved, (2) the address associated
760 with the hi index is always the one we want when the interation
761 terminates. In essence, we are iterating the test interval
762 down until the pc value is pushed out of it from the high end.
764 Warning: this code is trickier than it would appear at first. */
766 if (frob_address (objfile, &pc)
767 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
769 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
771 /* pc is still strictly less than highest address. */
772 /* Note "new" will always be >= lo. */
773 newobj = (lo + hi) / 2;
774 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
785 /* If we have multiple symbols at the same address, we want
786 hi to point to the last one. That way we can find the
787 right symbol if it has an index greater than hi. */
788 while (hi < objfile->per_bfd->minimal_symbol_count - 1
789 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
790 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
793 /* Skip various undesirable symbols. */
796 /* Skip any absolute symbols. This is apparently
797 what adb and dbx do, and is needed for the CM-5.
798 There are two known possible problems: (1) on
799 ELF, apparently end, edata, etc. are absolute.
800 Not sure ignoring them here is a big deal, but if
801 we want to use them, the fix would go in
802 elfread.c. (2) I think shared library entry
803 points on the NeXT are absolute. If we want
804 special handling for this it probably should be
805 triggered by a special mst_abs_or_lib or some
808 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
814 /* If SECTION was specified, skip any symbol from
817 /* Some types of debug info, such as COFF,
818 don't fill the bfd_section member, so don't
819 throw away symbols on those platforms. */
820 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
821 && (!matching_obj_sections
822 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
829 /* If we are looking for a trampoline and this is a
830 text symbol, or the other way around, check the
831 preceding symbol too. If they are otherwise
832 identical prefer that one. */
834 && MSYMBOL_TYPE (&msymbol[hi]) != want_type
835 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
836 && (MSYMBOL_SIZE (&msymbol[hi])
837 == MSYMBOL_SIZE (&msymbol[hi - 1]))
838 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
839 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
840 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
841 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
847 /* If the minimal symbol has a zero size, save it
848 but keep scanning backwards looking for one with
849 a non-zero size. A zero size may mean that the
850 symbol isn't an object or function (e.g. a
851 label), or it may just mean that the size was not
853 if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
855 if (best_zero_sized == -1)
856 best_zero_sized = hi;
861 /* If we are past the end of the current symbol, try
862 the previous symbol if it has a larger overlapping
863 size. This happens on i686-pc-linux-gnu with glibc;
864 the nocancel variants of system calls are inside
865 the cancellable variants, but both have sizes. */
867 && MSYMBOL_SIZE (&msymbol[hi]) != 0
868 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
869 + MSYMBOL_SIZE (&msymbol[hi]))
870 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
871 + MSYMBOL_SIZE (&msymbol[hi - 1])))
877 /* Otherwise, this symbol must be as good as we're going
882 /* If HI has a zero size, and best_zero_sized is set,
883 then we had two or more zero-sized symbols; prefer
884 the first one we found (which may have a higher
885 address). Also, if we ran off the end, be sure
887 if (best_zero_sized != -1
888 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
889 hi = best_zero_sized;
891 /* If the minimal symbol has a non-zero size, and this
892 PC appears to be outside the symbol's contents, then
893 refuse to use this symbol. If we found a zero-sized
894 symbol with an address greater than this symbol's,
895 use that instead. We assume that if symbols have
896 specified sizes, they do not overlap. */
899 && MSYMBOL_SIZE (&msymbol[hi]) != 0
900 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
901 + MSYMBOL_SIZE (&msymbol[hi])))
903 if (best_zero_sized != -1)
904 hi = best_zero_sized;
906 /* Go on to the next object file. */
910 /* The minimal symbol indexed by hi now is the best one in this
911 objfile's minimal symbol table. See if it is the best one
915 && ((best_symbol == NULL) ||
916 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
917 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
919 best_symbol = &msymbol[hi];
920 best_objfile = objfile;
926 result.minsym = best_symbol;
927 result.objfile = best_objfile;
933 struct bound_minimal_symbol
934 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
936 return lookup_minimal_symbol_by_pc_section (pc, NULL);
939 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
942 in_gnu_ifunc_stub (CORE_ADDR pc)
944 bound_minimal_symbol msymbol
945 = lookup_minimal_symbol_by_pc_section (pc, NULL,
946 lookup_msym_prefer::GNU_IFUNC);
947 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
950 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
953 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
955 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
956 "the ELF support compiled in."),
957 paddress (gdbarch, pc));
960 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
963 stub_gnu_ifunc_resolve_name (const char *function_name,
964 CORE_ADDR *function_address_p)
966 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
967 "the ELF support compiled in."),
971 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
974 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
976 internal_error (__FILE__, __LINE__,
977 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
980 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
983 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
985 internal_error (__FILE__, __LINE__,
986 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
989 /* See elf_gnu_ifunc_fns for its real implementation. */
991 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
993 stub_gnu_ifunc_resolve_addr,
994 stub_gnu_ifunc_resolve_name,
995 stub_gnu_ifunc_resolver_stop,
996 stub_gnu_ifunc_resolver_return_stop,
999 /* A placeholder for &elf_gnu_ifunc_fns. */
1001 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
1005 /* Return leading symbol character for a BFD. If BFD is NULL,
1006 return the leading symbol character from the main objfile. */
1009 get_symbol_leading_char (bfd *abfd)
1012 return bfd_get_symbol_leading_char (abfd);
1013 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
1014 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
1018 /* See minsyms.h. */
1020 minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj)
1022 m_msym_bunch (NULL),
1023 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1024 first call to save a minimal symbol to allocate the memory for
1026 m_msym_bunch_index (BUNCH_SIZE),
1031 /* Discard the currently collected minimal symbols, if any. If we wish
1032 to save them for later use, we must have already copied them somewhere
1033 else before calling this function. */
1035 minimal_symbol_reader::~minimal_symbol_reader ()
1037 struct msym_bunch *next;
1039 while (m_msym_bunch != NULL)
1041 next = m_msym_bunch->next;
1042 xfree (m_msym_bunch);
1043 m_msym_bunch = next;
1047 /* See minsyms.h. */
1050 minimal_symbol_reader::record (const char *name, CORE_ADDR address,
1051 enum minimal_symbol_type ms_type)
1058 case mst_text_gnu_ifunc:
1060 case mst_solib_trampoline:
1061 section = SECT_OFF_TEXT (m_objfile);
1064 case mst_data_gnu_ifunc:
1066 section = SECT_OFF_DATA (m_objfile);
1070 section = SECT_OFF_BSS (m_objfile);
1076 record_with_info (name, address, ms_type, section);
1079 /* Convert an enumerator of type minimal_symbol_type to its string
1083 mst_str (minimal_symbol_type t)
1085 #define MST_TO_STR(x) case x: return #x;
1088 MST_TO_STR (mst_unknown);
1089 MST_TO_STR (mst_text);
1090 MST_TO_STR (mst_text_gnu_ifunc);
1091 MST_TO_STR (mst_slot_got_plt);
1092 MST_TO_STR (mst_data);
1093 MST_TO_STR (mst_bss);
1094 MST_TO_STR (mst_abs);
1095 MST_TO_STR (mst_solib_trampoline);
1096 MST_TO_STR (mst_file_text);
1097 MST_TO_STR (mst_file_data);
1098 MST_TO_STR (mst_file_bss);
1106 /* See minsyms.h. */
1108 struct minimal_symbol *
1109 minimal_symbol_reader::record_full (const char *name, int name_len,
1110 bool copy_name, CORE_ADDR address,
1111 enum minimal_symbol_type ms_type,
1114 struct msym_bunch *newobj;
1115 struct minimal_symbol *msymbol;
1117 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1118 the minimal symbols, because if there is also another symbol
1119 at the same address (e.g. the first function of the file),
1120 lookup_minimal_symbol_by_pc would have no way of getting the
1122 if (ms_type == mst_file_text && name[0] == 'g'
1123 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
1124 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
1127 /* It's safe to strip the leading char here once, since the name
1128 is also stored stripped in the minimal symbol table. */
1129 if (name[0] == get_symbol_leading_char (m_objfile->obfd))
1135 if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
1138 if (symtab_create_debug >= 2)
1139 printf_unfiltered ("Recording minsym: %-21s %18s %4d %s\n",
1140 mst_str (ms_type), hex_string (address), section, name);
1142 if (m_msym_bunch_index == BUNCH_SIZE)
1144 newobj = XCNEW (struct msym_bunch);
1145 m_msym_bunch_index = 0;
1146 newobj->next = m_msym_bunch;
1147 m_msym_bunch = newobj;
1149 msymbol = &m_msym_bunch->contents[m_msym_bunch_index];
1150 symbol_set_language (msymbol, language_auto,
1151 &m_objfile->per_bfd->storage_obstack);
1152 symbol_set_names (msymbol, name, name_len, copy_name, m_objfile->per_bfd);
1154 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1155 MSYMBOL_SECTION (msymbol) = section;
1157 MSYMBOL_TYPE (msymbol) = ms_type;
1159 /* If we already read minimal symbols for this objfile, then don't
1160 ever allocate a new one. */
1161 if (!m_objfile->per_bfd->minsyms_read)
1163 m_msym_bunch_index++;
1164 m_objfile->per_bfd->n_minsyms++;
1170 /* Compare two minimal symbols by address and return a signed result based
1171 on unsigned comparisons, so that we sort into unsigned numeric order.
1172 Within groups with the same address, sort by name. */
1175 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1177 const struct minimal_symbol *fn1;
1178 const struct minimal_symbol *fn2;
1180 fn1 = (const struct minimal_symbol *) fn1p;
1181 fn2 = (const struct minimal_symbol *) fn2p;
1183 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1185 return (-1); /* addr 1 is less than addr 2. */
1187 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1189 return (1); /* addr 1 is greater than addr 2. */
1192 /* addrs are equal: sort by name */
1194 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1195 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1197 if (name1 && name2) /* both have names */
1198 return strcmp (name1, name2);
1200 return 1; /* fn1 has no name, so it is "less". */
1201 else if (name1) /* fn2 has no name, so it is "less". */
1204 return (0); /* Neither has a name, so they're equal. */
1208 /* Compact duplicate entries out of a minimal symbol table by walking
1209 through the table and compacting out entries with duplicate addresses
1210 and matching names. Return the number of entries remaining.
1212 On entry, the table resides between msymbol[0] and msymbol[mcount].
1213 On exit, it resides between msymbol[0] and msymbol[result_count].
1215 When files contain multiple sources of symbol information, it is
1216 possible for the minimal symbol table to contain many duplicate entries.
1217 As an example, SVR4 systems use ELF formatted object files, which
1218 usually contain at least two different types of symbol tables (a
1219 standard ELF one and a smaller dynamic linking table), as well as
1220 DWARF debugging information for files compiled with -g.
1222 Without compacting, the minimal symbol table for gdb itself contains
1223 over a 1000 duplicates, about a third of the total table size. Aside
1224 from the potential trap of not noticing that two successive entries
1225 identify the same location, this duplication impacts the time required
1226 to linearly scan the table, which is done in a number of places. So we
1227 just do one linear scan here and toss out the duplicates.
1229 Since the different sources of information for each symbol may
1230 have different levels of "completeness", we may have duplicates
1231 that have one entry with type "mst_unknown" and the other with a
1232 known type. So if the one we are leaving alone has type mst_unknown,
1233 overwrite its type with the type from the one we are compacting out. */
1236 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1237 struct objfile *objfile)
1239 struct minimal_symbol *copyfrom;
1240 struct minimal_symbol *copyto;
1244 copyfrom = copyto = msymbol;
1245 while (copyfrom < msymbol + mcount - 1)
1247 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1248 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1249 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1250 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1251 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1253 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1255 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1260 *copyto++ = *copyfrom++;
1262 *copyto++ = *copyfrom++;
1263 mcount = copyto - msymbol;
1268 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1269 after compacting or sorting the table since the entries move around
1270 thus causing the internal minimal_symbol pointers to become jumbled. */
1273 build_minimal_symbol_hash_tables (struct objfile *objfile)
1276 struct minimal_symbol *msym;
1278 /* Clear the hash tables. */
1279 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1281 objfile->per_bfd->msymbol_hash[i] = 0;
1282 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1285 /* Now, (re)insert the actual entries. */
1286 for ((i = objfile->per_bfd->minimal_symbol_count,
1287 msym = objfile->per_bfd->msymbols.get ());
1291 msym->hash_next = 0;
1292 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1294 msym->demangled_hash_next = 0;
1295 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1296 add_minsym_to_demangled_hash_table (msym, objfile);
1300 /* Add the minimal symbols in the existing bunches to the objfile's official
1301 minimal symbol table. In most cases there is no minimal symbol table yet
1302 for this objfile, and the existing bunches are used to create one. Once
1303 in a while (for shared libraries for example), we add symbols (e.g. common
1304 symbols) to an existing objfile. */
1307 minimal_symbol_reader::install ()
1310 struct msym_bunch *bunch;
1311 struct minimal_symbol *msymbols;
1314 if (m_objfile->per_bfd->minsyms_read)
1317 if (m_msym_count > 0)
1319 if (symtab_create_debug)
1321 fprintf_unfiltered (gdb_stdlog,
1322 "Installing %d minimal symbols of objfile %s.\n",
1323 m_msym_count, objfile_name (m_objfile));
1326 /* Allocate enough space, into which we will gather the bunches
1327 of new and existing minimal symbols, sort them, and then
1328 compact out the duplicate entries. Once we have a final
1329 table, we will give back the excess space. */
1331 alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count;
1332 gdb::unique_xmalloc_ptr<minimal_symbol>
1333 msym_holder (XNEWVEC (minimal_symbol, alloc_count));
1334 msymbols = msym_holder.get ();
1336 /* Copy in the existing minimal symbols, if there are any. */
1338 if (m_objfile->per_bfd->minimal_symbol_count)
1339 memcpy (msymbols, m_objfile->per_bfd->msymbols.get (),
1340 m_objfile->per_bfd->minimal_symbol_count
1341 * sizeof (struct minimal_symbol));
1343 /* Walk through the list of minimal symbol bunches, adding each symbol
1344 to the new contiguous array of symbols. Note that we start with the
1345 current, possibly partially filled bunch (thus we use the current
1346 msym_bunch_index for the first bunch we copy over), and thereafter
1347 each bunch is full. */
1349 mcount = m_objfile->per_bfd->minimal_symbol_count;
1351 for (bunch = m_msym_bunch; bunch != NULL; bunch = bunch->next)
1353 memcpy (&msymbols[mcount], &bunch->contents[0],
1354 m_msym_bunch_index * sizeof (struct minimal_symbol));
1355 mcount += m_msym_bunch_index;
1356 m_msym_bunch_index = BUNCH_SIZE;
1359 /* Sort the minimal symbols by address. */
1361 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1362 compare_minimal_symbols);
1364 /* Compact out any duplicates, and free up whatever space we are
1367 mcount = compact_minimal_symbols (msymbols, mcount, m_objfile);
1368 msym_holder.reset (XRESIZEVEC (struct minimal_symbol,
1369 msym_holder.release (),
1372 /* Attach the minimal symbol table to the specified objfile.
1373 The strings themselves are also located in the storage_obstack
1376 m_objfile->per_bfd->minimal_symbol_count = mcount;
1377 m_objfile->per_bfd->msymbols = std::move (msym_holder);
1379 build_minimal_symbol_hash_tables (m_objfile);
1383 /* Check if PC is in a shared library trampoline code stub.
1384 Return minimal symbol for the trampoline entry or NULL if PC is not
1385 in a trampoline code stub. */
1387 static struct minimal_symbol *
1388 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1390 bound_minimal_symbol msymbol
1391 = lookup_minimal_symbol_by_pc_section (pc, NULL,
1392 lookup_msym_prefer::TRAMPOLINE);
1394 if (msymbol.minsym != NULL
1395 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1396 return msymbol.minsym;
1400 /* If PC is in a shared library trampoline code stub, return the
1401 address of the `real' function belonging to the stub.
1402 Return 0 if PC is not in a trampoline code stub or if the real
1403 function is not found in the minimal symbol table.
1405 We may fail to find the right function if a function with the
1406 same name is defined in more than one shared library, but this
1407 is considered bad programming style. We could return 0 if we find
1408 a duplicate function in case this matters someday. */
1411 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1413 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1415 if (tsymbol != NULL)
1417 for (objfile *objfile : current_program_space->objfiles ())
1419 for (minimal_symbol *msymbol : objfile->msymbols ())
1421 /* Also handle minimal symbols pointing to function
1423 if ((MSYMBOL_TYPE (msymbol) == mst_text
1424 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
1425 || MSYMBOL_TYPE (msymbol) == mst_data
1426 || MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc)
1427 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1428 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1432 /* Ignore data symbols that are not function
1434 if (msymbol_is_function (objfile, msymbol, &func))
1443 /* See minsyms.h. */
1446 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1449 struct obj_section *obj_section;
1451 struct minimal_symbol *iter, *msymbol;
1453 gdb_assert (minsym.minsym != NULL);
1455 /* If the minimal symbol has a size, use it. Otherwise use the
1456 lesser of the next minimal symbol in the same section, or the end
1457 of the section, as the end of the function. */
1459 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1460 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1462 /* Step over other symbols at this same address, and symbols in
1463 other sections, to find the next symbol in this section with a
1464 different address. */
1466 struct minimal_symbol *past_the_end
1467 = (minsym.objfile->per_bfd->msymbols.get ()
1468 + minsym.objfile->per_bfd->minimal_symbol_count);
1469 msymbol = minsym.minsym;
1470 section = MSYMBOL_SECTION (msymbol);
1471 for (iter = msymbol + 1; iter != past_the_end; ++iter)
1473 if ((MSYMBOL_VALUE_RAW_ADDRESS (iter)
1474 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1475 && MSYMBOL_SECTION (iter) == section)
1479 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1480 if (iter != past_the_end
1481 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, iter)
1482 < obj_section_endaddr (obj_section)))
1483 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, iter);
1485 /* We got the start address from the last msymbol in the objfile.
1486 So the end address is the end of the section. */
1487 result = obj_section_endaddr (obj_section);