1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2018 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:
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 location on an objfile's
96 per-BFD storage obstack. */
98 #define BUNCH_SIZE 127
102 struct msym_bunch *next;
103 struct minimal_symbol contents[BUNCH_SIZE];
109 msymbol_hash_iw (const char *string)
111 unsigned int hash = 0;
113 while (*string && *string != '(')
115 string = skip_spaces (string);
116 if (*string && *string != '(')
118 hash = SYMBOL_HASH_NEXT (hash, *string);
128 msymbol_hash (const char *string)
130 unsigned int hash = 0;
132 for (; *string; ++string)
133 hash = SYMBOL_HASH_NEXT (hash, *string);
137 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
139 add_minsym_to_hash_table (struct minimal_symbol *sym,
140 struct minimal_symbol **table)
142 if (sym->hash_next == NULL)
145 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
147 sym->hash_next = table[hash];
152 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
155 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
156 struct objfile *objfile)
158 if (sym->demangled_hash_next == NULL)
160 unsigned int hash = search_name_hash (MSYMBOL_LANGUAGE (sym),
161 MSYMBOL_SEARCH_NAME (sym));
163 auto &vec = objfile->per_bfd->demangled_hash_languages;
164 auto it = std::lower_bound (vec.begin (), vec.end (),
165 MSYMBOL_LANGUAGE (sym));
166 if (it == vec.end () || *it != MSYMBOL_LANGUAGE (sym))
167 vec.insert (it, MSYMBOL_LANGUAGE (sym));
169 struct minimal_symbol **table
170 = objfile->per_bfd->msymbol_demangled_hash;
171 unsigned int hash_index = hash % MINIMAL_SYMBOL_HASH_SIZE;
172 sym->demangled_hash_next = table[hash_index];
173 table[hash_index] = sym;
177 /* Worker object for lookup_minimal_symbol. Stores temporary results
178 while walking the symbol tables. */
180 struct found_minimal_symbols
182 /* External symbols are best. */
183 bound_minimal_symbol external_symbol {};
185 /* File-local symbols are next best. */
186 bound_minimal_symbol file_symbol {};
188 /* Symbols for shared library trampolines are next best. */
189 bound_minimal_symbol trampoline_symbol {};
191 /* Called when a symbol name matches. Check if the minsym is a
192 better type than what we had already found, and record it in one
193 of the members fields if so. Returns true if we collected the
194 real symbol, in which case we can stop searching. */
195 bool maybe_collect (const char *sfile, objfile *objf,
196 minimal_symbol *msymbol);
199 /* See declaration above. */
202 found_minimal_symbols::maybe_collect (const char *sfile,
203 struct objfile *objfile,
204 minimal_symbol *msymbol)
206 switch (MSYMBOL_TYPE (msymbol))
212 || filename_cmp (msymbol->filename, sfile) == 0)
214 file_symbol.minsym = msymbol;
215 file_symbol.objfile = objfile;
219 case mst_solib_trampoline:
221 /* If a trampoline symbol is found, we prefer to keep
222 looking for the *real* symbol. If the actual symbol
223 is not found, then we'll use the trampoline
225 if (trampoline_symbol.minsym == NULL)
227 trampoline_symbol.minsym = msymbol;
228 trampoline_symbol.objfile = objfile;
234 external_symbol.minsym = msymbol;
235 external_symbol.objfile = objfile;
236 /* We have the real symbol. No use looking further. */
244 /* Walk the mangled name hash table, and pass each symbol whose name
245 matches LOOKUP_NAME according to NAMECMP to FOUND. */
248 lookup_minimal_symbol_mangled (const char *lookup_name,
250 struct objfile *objfile,
251 struct minimal_symbol **table,
253 int (*namecmp) (const char *, const char *),
254 found_minimal_symbols &found)
256 for (minimal_symbol *msymbol = table[hash];
258 msymbol = msymbol->hash_next)
260 const char *symbol_name = MSYMBOL_LINKAGE_NAME (msymbol);
262 if (namecmp (symbol_name, lookup_name) == 0
263 && found.maybe_collect (sfile, objfile, msymbol))
268 /* Walk the demangled name hash table, and pass each symbol whose name
269 matches LOOKUP_NAME according to MATCHER to FOUND. */
272 lookup_minimal_symbol_demangled (const lookup_name_info &lookup_name,
274 struct objfile *objfile,
275 struct minimal_symbol **table,
277 symbol_name_matcher_ftype *matcher,
278 found_minimal_symbols &found)
280 for (minimal_symbol *msymbol = table[hash];
282 msymbol = msymbol->demangled_hash_next)
284 const char *symbol_name = MSYMBOL_SEARCH_NAME (msymbol);
286 if (matcher (symbol_name, lookup_name, NULL)
287 && found.maybe_collect (sfile, objfile, msymbol))
292 /* Look through all the current minimal symbol tables and find the
293 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
294 the search to that objfile. If SFILE is non-NULL, the only file-scope
295 symbols considered will be from that source file (global symbols are
296 still preferred). Returns a pointer to the minimal symbol that
297 matches, or NULL if no match is found.
299 Note: One instance where there may be duplicate minimal symbols with
300 the same name is when the symbol tables for a shared library and the
301 symbol tables for an executable contain global symbols with the same
302 names (the dynamic linker deals with the duplication).
304 It's also possible to have minimal symbols with different mangled
305 names, but identical demangled names. For example, the GNU C++ v3
306 ABI requires the generation of two (or perhaps three) copies of
307 constructor functions --- "in-charge", "not-in-charge", and
308 "allocate" copies; destructors may be duplicated as well.
309 Obviously, there must be distinct mangled names for each of these,
310 but the demangled names are all the same: S::S or S::~S. */
312 struct bound_minimal_symbol
313 lookup_minimal_symbol (const char *name, const char *sfile,
314 struct objfile *objf)
316 struct objfile *objfile;
317 found_minimal_symbols found;
319 unsigned int mangled_hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
322 = (case_sensitivity == case_sensitive_on
327 sfile = lbasename (sfile);
329 lookup_name_info lookup_name (name, symbol_name_match_type::FULL);
331 for (objfile = object_files;
332 objfile != NULL && found.external_symbol.minsym == NULL;
333 objfile = objfile->next)
335 if (objf == NULL || objf == objfile
336 || objf == objfile->separate_debug_objfile_backlink)
338 if (symbol_lookup_debug)
340 fprintf_unfiltered (gdb_stdlog,
341 "lookup_minimal_symbol (%s, %s, %s)\n",
342 name, sfile != NULL ? sfile : "NULL",
343 objfile_debug_name (objfile));
346 /* Do two passes: the first over the ordinary hash table,
347 and the second over the demangled hash table. */
348 lookup_minimal_symbol_mangled (name, sfile, objfile,
349 objfile->per_bfd->msymbol_hash,
350 mangled_hash, mangled_cmp, found);
352 /* If not found, try the demangled hash table. */
353 if (found.external_symbol.minsym == NULL)
355 /* Once for each language in the demangled hash names
356 table (usually just zero or one languages). */
357 for (auto lang : objfile->per_bfd->demangled_hash_languages)
360 = (lookup_name.search_name_hash (lang)
361 % MINIMAL_SYMBOL_HASH_SIZE);
363 symbol_name_matcher_ftype *match
364 = get_symbol_name_matcher (language_def (lang),
366 struct minimal_symbol **msymbol_demangled_hash
367 = objfile->per_bfd->msymbol_demangled_hash;
369 lookup_minimal_symbol_demangled (lookup_name, sfile, objfile,
370 msymbol_demangled_hash,
373 if (found.external_symbol.minsym != NULL)
380 /* External symbols are best. */
381 if (found.external_symbol.minsym != NULL)
383 if (symbol_lookup_debug)
385 minimal_symbol *minsym = found.external_symbol.minsym;
387 fprintf_unfiltered (gdb_stdlog,
388 "lookup_minimal_symbol (...) = %s (external)\n",
389 host_address_to_string (minsym));
391 return found.external_symbol;
394 /* File-local symbols are next best. */
395 if (found.file_symbol.minsym != NULL)
397 if (symbol_lookup_debug)
399 minimal_symbol *minsym = found.file_symbol.minsym;
401 fprintf_unfiltered (gdb_stdlog,
402 "lookup_minimal_symbol (...) = %s (file-local)\n",
403 host_address_to_string (minsym));
405 return found.file_symbol;
408 /* Symbols for shared library trampolines are next best. */
409 if (found.trampoline_symbol.minsym != NULL)
411 if (symbol_lookup_debug)
413 minimal_symbol *minsym = found.trampoline_symbol.minsym;
415 fprintf_unfiltered (gdb_stdlog,
416 "lookup_minimal_symbol (...) = %s (trampoline)\n",
417 host_address_to_string (minsym));
420 return found.trampoline_symbol;
424 if (symbol_lookup_debug)
425 fprintf_unfiltered (gdb_stdlog, "lookup_minimal_symbol (...) = NULL\n");
431 struct bound_minimal_symbol
432 lookup_bound_minimal_symbol (const char *name)
434 return lookup_minimal_symbol (name, NULL, NULL);
437 /* See common/symbol.h. */
440 find_minimal_symbol_address (const char *name, CORE_ADDR *addr,
441 struct objfile *objfile)
443 struct bound_minimal_symbol sym
444 = lookup_minimal_symbol (name, NULL, objfile);
446 if (sym.minsym != NULL)
447 *addr = BMSYMBOL_VALUE_ADDRESS (sym);
449 return sym.minsym == NULL;
452 /* Get the lookup name form best suitable for linkage name
456 linkage_name_str (const lookup_name_info &lookup_name)
458 /* Unlike most languages (including C++), Ada uses the
459 encoded/linkage name as the search name recorded in symbols. So
460 if debugging in Ada mode, prefer the Ada-encoded name. This also
461 makes Ada's verbatim match syntax ("<...>") work, because
462 "lookup_name.name()" includes the "<>"s, while
463 "lookup_name.ada().lookup_name()" is the encoded name with "<>"s
465 if (current_language->la_language == language_ada)
466 return lookup_name.ada ().lookup_name ().c_str ();
468 return lookup_name.name ().c_str ();
474 iterate_over_minimal_symbols
475 (struct objfile *objf, const lookup_name_info &lookup_name,
476 gdb::function_view<bool (struct minimal_symbol *)> callback)
478 /* The first pass is over the ordinary hash table. */
480 const char *name = linkage_name_str (lookup_name);
481 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
483 = (case_sensitivity == case_sensitive_on
487 for (minimal_symbol *iter = objf->per_bfd->msymbol_hash[hash];
489 iter = iter->hash_next)
491 if (mangled_cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
497 /* The second pass is over the demangled table. Once for each
498 language in the demangled hash names table (usually just zero or
500 for (auto lang : objf->per_bfd->demangled_hash_languages)
502 const language_defn *lang_def = language_def (lang);
503 symbol_name_matcher_ftype *name_match
504 = get_symbol_name_matcher (lang_def, lookup_name);
507 = lookup_name.search_name_hash (lang) % MINIMAL_SYMBOL_HASH_SIZE;
508 for (minimal_symbol *iter = objf->per_bfd->msymbol_demangled_hash[hash];
510 iter = iter->demangled_hash_next)
511 if (name_match (MSYMBOL_SEARCH_NAME (iter), lookup_name, NULL))
519 struct bound_minimal_symbol
520 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
522 struct objfile *objfile;
523 struct minimal_symbol *msymbol;
524 struct bound_minimal_symbol found_symbol = { NULL, NULL };
525 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
527 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
529 for (objfile = object_files;
530 objfile != NULL && found_symbol.minsym == NULL;
531 objfile = objfile->next)
533 if (objf == NULL || objf == objfile
534 || objf == objfile->separate_debug_objfile_backlink)
536 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
537 msymbol != NULL && found_symbol.minsym == NULL;
538 msymbol = msymbol->hash_next)
540 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
541 (MSYMBOL_TYPE (msymbol) == mst_text
542 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
543 || MSYMBOL_TYPE (msymbol) == mst_file_text))
545 switch (MSYMBOL_TYPE (msymbol))
548 found_file_symbol.minsym = msymbol;
549 found_file_symbol.objfile = objfile;
552 found_symbol.minsym = msymbol;
553 found_symbol.objfile = objfile;
560 /* External symbols are best. */
561 if (found_symbol.minsym)
564 /* File-local symbols are next best. */
565 return found_file_symbol;
570 struct minimal_symbol *
571 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
572 struct objfile *objf)
574 struct objfile *objfile;
575 struct minimal_symbol *msymbol;
577 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
579 for (objfile = object_files;
581 objfile = objfile->next)
583 if (objf == NULL || objf == objfile
584 || objf == objfile->separate_debug_objfile_backlink)
586 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
588 msymbol = msymbol->hash_next)
590 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
591 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
602 struct bound_minimal_symbol
603 lookup_minimal_symbol_solib_trampoline (const char *name,
604 struct objfile *objf)
606 struct objfile *objfile;
607 struct minimal_symbol *msymbol;
608 struct bound_minimal_symbol found_symbol = { NULL, NULL };
610 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
612 for (objfile = object_files;
614 objfile = objfile->next)
616 if (objf == NULL || objf == objfile
617 || objf == objfile->separate_debug_objfile_backlink)
619 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
621 msymbol = msymbol->hash_next)
623 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
624 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
626 found_symbol.objfile = objfile;
627 found_symbol.minsym = msymbol;
637 /* A helper function that makes *PC section-relative. This searches
638 the sections of OBJFILE and if *PC is in a section, it subtracts
639 the section offset and returns true. Otherwise it returns
643 frob_address (struct objfile *objfile, CORE_ADDR *pc)
645 struct obj_section *iter;
647 ALL_OBJFILE_OSECTIONS (objfile, iter)
649 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
651 *pc -= obj_section_offset (iter);
659 /* Search through the minimal symbol table for each objfile and find
660 the symbol whose address is the largest address that is still less
661 than or equal to PC, and matches SECTION (which is not NULL).
662 Returns a pointer to the minimal symbol if such a symbol is found,
663 or NULL if PC is not in a suitable range.
664 Note that we need to look through ALL the minimal symbol tables
665 before deciding on the symbol that comes closest to the specified PC.
666 This is because objfiles can overlap, for example objfile A has .text
667 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
670 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
671 there are text and trampoline symbols at the same address.
672 Otherwise prefer mst_text symbols. */
675 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *section,
676 lookup_msym_prefer prefer)
681 struct objfile *objfile;
682 struct minimal_symbol *msymbol;
683 struct minimal_symbol *best_symbol = NULL;
684 struct objfile *best_objfile = NULL;
685 struct bound_minimal_symbol result;
686 enum minimal_symbol_type want_type;
690 section = find_pc_section (pc_in);
697 case lookup_msym_prefer::TEXT:
698 want_type = mst_text;
700 case lookup_msym_prefer::TRAMPOLINE:
701 want_type = mst_solib_trampoline;
703 case lookup_msym_prefer::GNU_IFUNC:
704 want_type = mst_text_gnu_ifunc;
708 /* We can not require the symbol found to be in section, because
709 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
710 symbol - but find_pc_section won't return an absolute section and
711 hence the code below would skip over absolute symbols. We can
712 still take advantage of the call to find_pc_section, though - the
713 object file still must match. In case we have separate debug
714 files, search both the file and its separate debug file. There's
715 no telling which one will have the minimal symbols. */
717 gdb_assert (section != NULL);
719 for (objfile = section->objfile;
721 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
723 CORE_ADDR pc = pc_in;
725 /* If this objfile has a minimal symbol table, go search it using
726 a binary search. Note that a minimal symbol table always consists
727 of at least two symbols, a "real" symbol and the terminating
728 "null symbol". If there are no real symbols, then there is no
729 minimal symbol table at all. */
731 if (objfile->per_bfd->minimal_symbol_count > 0)
733 int best_zero_sized = -1;
735 msymbol = objfile->per_bfd->msymbols;
737 hi = objfile->per_bfd->minimal_symbol_count - 1;
739 /* This code assumes that the minimal symbols are sorted by
740 ascending address values. If the pc value is greater than or
741 equal to the first symbol's address, then some symbol in this
742 minimal symbol table is a suitable candidate for being the
743 "best" symbol. This includes the last real symbol, for cases
744 where the pc value is larger than any address in this vector.
746 By iterating until the address associated with the current
747 hi index (the endpoint of the test interval) is less than
748 or equal to the desired pc value, we accomplish two things:
749 (1) the case where the pc value is larger than any minimal
750 symbol address is trivially solved, (2) the address associated
751 with the hi index is always the one we want when the interation
752 terminates. In essence, we are iterating the test interval
753 down until the pc value is pushed out of it from the high end.
755 Warning: this code is trickier than it would appear at first. */
757 if (frob_address (objfile, &pc)
758 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
760 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
762 /* pc is still strictly less than highest address. */
763 /* Note "new" will always be >= lo. */
764 newobj = (lo + hi) / 2;
765 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
776 /* If we have multiple symbols at the same address, we want
777 hi to point to the last one. That way we can find the
778 right symbol if it has an index greater than hi. */
779 while (hi < objfile->per_bfd->minimal_symbol_count - 1
780 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
781 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
784 /* Skip various undesirable symbols. */
787 /* Skip any absolute symbols. This is apparently
788 what adb and dbx do, and is needed for the CM-5.
789 There are two known possible problems: (1) on
790 ELF, apparently end, edata, etc. are absolute.
791 Not sure ignoring them here is a big deal, but if
792 we want to use them, the fix would go in
793 elfread.c. (2) I think shared library entry
794 points on the NeXT are absolute. If we want
795 special handling for this it probably should be
796 triggered by a special mst_abs_or_lib or some
799 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
805 /* If SECTION was specified, skip any symbol from
808 /* Some types of debug info, such as COFF,
809 don't fill the bfd_section member, so don't
810 throw away symbols on those platforms. */
811 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
812 && (!matching_obj_sections
813 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
820 /* If we are looking for a trampoline and this is a
821 text symbol, or the other way around, check the
822 preceding symbol too. If they are otherwise
823 identical prefer that one. */
825 && MSYMBOL_TYPE (&msymbol[hi]) != want_type
826 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
827 && (MSYMBOL_SIZE (&msymbol[hi])
828 == MSYMBOL_SIZE (&msymbol[hi - 1]))
829 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
830 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
831 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
832 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
838 /* If the minimal symbol has a zero size, save it
839 but keep scanning backwards looking for one with
840 a non-zero size. A zero size may mean that the
841 symbol isn't an object or function (e.g. a
842 label), or it may just mean that the size was not
844 if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
846 if (best_zero_sized == -1)
847 best_zero_sized = hi;
852 /* If we are past the end of the current symbol, try
853 the previous symbol if it has a larger overlapping
854 size. This happens on i686-pc-linux-gnu with glibc;
855 the nocancel variants of system calls are inside
856 the cancellable variants, but both have sizes. */
858 && MSYMBOL_SIZE (&msymbol[hi]) != 0
859 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
860 + MSYMBOL_SIZE (&msymbol[hi]))
861 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
862 + MSYMBOL_SIZE (&msymbol[hi - 1])))
868 /* Otherwise, this symbol must be as good as we're going
873 /* If HI has a zero size, and best_zero_sized is set,
874 then we had two or more zero-sized symbols; prefer
875 the first one we found (which may have a higher
876 address). Also, if we ran off the end, be sure
878 if (best_zero_sized != -1
879 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
880 hi = best_zero_sized;
882 /* If the minimal symbol has a non-zero size, and this
883 PC appears to be outside the symbol's contents, then
884 refuse to use this symbol. If we found a zero-sized
885 symbol with an address greater than this symbol's,
886 use that instead. We assume that if symbols have
887 specified sizes, they do not overlap. */
890 && MSYMBOL_SIZE (&msymbol[hi]) != 0
891 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
892 + MSYMBOL_SIZE (&msymbol[hi])))
894 if (best_zero_sized != -1)
895 hi = best_zero_sized;
897 /* Go on to the next object file. */
901 /* The minimal symbol indexed by hi now is the best one in this
902 objfile's minimal symbol table. See if it is the best one
906 && ((best_symbol == NULL) ||
907 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
908 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
910 best_symbol = &msymbol[hi];
911 best_objfile = objfile;
917 result.minsym = best_symbol;
918 result.objfile = best_objfile;
924 struct bound_minimal_symbol
925 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
927 return lookup_minimal_symbol_by_pc_section (pc, NULL);
930 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
933 in_gnu_ifunc_stub (CORE_ADDR pc)
935 bound_minimal_symbol msymbol
936 = lookup_minimal_symbol_by_pc_section (pc, NULL,
937 lookup_msym_prefer::GNU_IFUNC);
938 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
941 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
944 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
946 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
947 "the ELF support compiled in."),
948 paddress (gdbarch, pc));
951 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
954 stub_gnu_ifunc_resolve_name (const char *function_name,
955 CORE_ADDR *function_address_p)
957 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
958 "the ELF support compiled in."),
962 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
965 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
967 internal_error (__FILE__, __LINE__,
968 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
971 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
974 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
976 internal_error (__FILE__, __LINE__,
977 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
980 /* See elf_gnu_ifunc_fns for its real implementation. */
982 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
984 stub_gnu_ifunc_resolve_addr,
985 stub_gnu_ifunc_resolve_name,
986 stub_gnu_ifunc_resolver_stop,
987 stub_gnu_ifunc_resolver_return_stop,
990 /* A placeholder for &elf_gnu_ifunc_fns. */
992 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
996 /* Return leading symbol character for a BFD. If BFD is NULL,
997 return the leading symbol character from the main objfile. */
1000 get_symbol_leading_char (bfd *abfd)
1003 return bfd_get_symbol_leading_char (abfd);
1004 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
1005 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
1009 /* See minsyms.h. */
1011 minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj)
1013 m_msym_bunch (NULL),
1014 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1015 first call to save a minimal symbol to allocate the memory for
1017 m_msym_bunch_index (BUNCH_SIZE),
1022 /* Discard the currently collected minimal symbols, if any. If we wish
1023 to save them for later use, we must have already copied them somewhere
1024 else before calling this function.
1026 FIXME: We could allocate the minimal symbol bunches on their own
1027 obstack and then simply blow the obstack away when we are done with
1028 it. Is it worth the extra trouble though? */
1030 minimal_symbol_reader::~minimal_symbol_reader ()
1032 struct msym_bunch *next;
1034 while (m_msym_bunch != NULL)
1036 next = m_msym_bunch->next;
1037 xfree (m_msym_bunch);
1038 m_msym_bunch = next;
1042 /* See minsyms.h. */
1045 minimal_symbol_reader::record (const char *name, CORE_ADDR address,
1046 enum minimal_symbol_type ms_type)
1053 case mst_text_gnu_ifunc:
1055 case mst_solib_trampoline:
1056 section = SECT_OFF_TEXT (m_objfile);
1059 case mst_data_gnu_ifunc:
1061 section = SECT_OFF_DATA (m_objfile);
1065 section = SECT_OFF_BSS (m_objfile);
1071 record_with_info (name, address, ms_type, section);
1074 /* See minsyms.h. */
1076 struct minimal_symbol *
1077 minimal_symbol_reader::record_full (const char *name, int name_len,
1078 bool copy_name, CORE_ADDR address,
1079 enum minimal_symbol_type ms_type,
1082 struct msym_bunch *newobj;
1083 struct minimal_symbol *msymbol;
1085 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1086 the minimal symbols, because if there is also another symbol
1087 at the same address (e.g. the first function of the file),
1088 lookup_minimal_symbol_by_pc would have no way of getting the
1090 if (ms_type == mst_file_text && name[0] == 'g'
1091 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
1092 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
1095 /* It's safe to strip the leading char here once, since the name
1096 is also stored stripped in the minimal symbol table. */
1097 if (name[0] == get_symbol_leading_char (m_objfile->obfd))
1103 if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
1106 if (m_msym_bunch_index == BUNCH_SIZE)
1108 newobj = XCNEW (struct msym_bunch);
1109 m_msym_bunch_index = 0;
1110 newobj->next = m_msym_bunch;
1111 m_msym_bunch = newobj;
1113 msymbol = &m_msym_bunch->contents[m_msym_bunch_index];
1114 MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
1115 &m_objfile->per_bfd->storage_obstack);
1116 MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, m_objfile);
1118 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1119 MSYMBOL_SECTION (msymbol) = section;
1121 MSYMBOL_TYPE (msymbol) = ms_type;
1122 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
1123 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
1124 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
1125 as it would also set the has_size flag. */
1128 /* The hash pointers must be cleared! If they're not,
1129 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
1130 msymbol->hash_next = NULL;
1131 msymbol->demangled_hash_next = NULL;
1133 /* If we already read minimal symbols for this objfile, then don't
1134 ever allocate a new one. */
1135 if (!m_objfile->per_bfd->minsyms_read)
1137 m_msym_bunch_index++;
1138 m_objfile->per_bfd->n_minsyms++;
1144 /* Compare two minimal symbols by address and return a signed result based
1145 on unsigned comparisons, so that we sort into unsigned numeric order.
1146 Within groups with the same address, sort by name. */
1149 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1151 const struct minimal_symbol *fn1;
1152 const struct minimal_symbol *fn2;
1154 fn1 = (const struct minimal_symbol *) fn1p;
1155 fn2 = (const struct minimal_symbol *) fn2p;
1157 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1159 return (-1); /* addr 1 is less than addr 2. */
1161 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1163 return (1); /* addr 1 is greater than addr 2. */
1166 /* addrs are equal: sort by name */
1168 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1169 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1171 if (name1 && name2) /* both have names */
1172 return strcmp (name1, name2);
1174 return 1; /* fn1 has no name, so it is "less". */
1175 else if (name1) /* fn2 has no name, so it is "less". */
1178 return (0); /* Neither has a name, so they're equal. */
1182 /* Compact duplicate entries out of a minimal symbol table by walking
1183 through the table and compacting out entries with duplicate addresses
1184 and matching names. Return the number of entries remaining.
1186 On entry, the table resides between msymbol[0] and msymbol[mcount].
1187 On exit, it resides between msymbol[0] and msymbol[result_count].
1189 When files contain multiple sources of symbol information, it is
1190 possible for the minimal symbol table to contain many duplicate entries.
1191 As an example, SVR4 systems use ELF formatted object files, which
1192 usually contain at least two different types of symbol tables (a
1193 standard ELF one and a smaller dynamic linking table), as well as
1194 DWARF debugging information for files compiled with -g.
1196 Without compacting, the minimal symbol table for gdb itself contains
1197 over a 1000 duplicates, about a third of the total table size. Aside
1198 from the potential trap of not noticing that two successive entries
1199 identify the same location, this duplication impacts the time required
1200 to linearly scan the table, which is done in a number of places. So we
1201 just do one linear scan here and toss out the duplicates.
1203 Note that we are not concerned here about recovering the space that
1204 is potentially freed up, because the strings themselves are allocated
1205 on the storage_obstack, and will get automatically freed when the symbol
1206 table is freed. The caller can free up the unused minimal symbols at
1207 the end of the compacted region if their allocation strategy allows it.
1209 Also note we only go up to the next to last entry within the loop
1210 and then copy the last entry explicitly after the loop terminates.
1212 Since the different sources of information for each symbol may
1213 have different levels of "completeness", we may have duplicates
1214 that have one entry with type "mst_unknown" and the other with a
1215 known type. So if the one we are leaving alone has type mst_unknown,
1216 overwrite its type with the type from the one we are compacting out. */
1219 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1220 struct objfile *objfile)
1222 struct minimal_symbol *copyfrom;
1223 struct minimal_symbol *copyto;
1227 copyfrom = copyto = msymbol;
1228 while (copyfrom < msymbol + mcount - 1)
1230 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1231 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1232 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1233 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1234 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1236 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1238 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1243 *copyto++ = *copyfrom++;
1245 *copyto++ = *copyfrom++;
1246 mcount = copyto - msymbol;
1251 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1252 after compacting or sorting the table since the entries move around
1253 thus causing the internal minimal_symbol pointers to become jumbled. */
1256 build_minimal_symbol_hash_tables (struct objfile *objfile)
1259 struct minimal_symbol *msym;
1261 /* Clear the hash tables. */
1262 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1264 objfile->per_bfd->msymbol_hash[i] = 0;
1265 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1268 /* Now, (re)insert the actual entries. */
1269 for ((i = objfile->per_bfd->minimal_symbol_count,
1270 msym = objfile->per_bfd->msymbols);
1274 msym->hash_next = 0;
1275 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1277 msym->demangled_hash_next = 0;
1278 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1279 add_minsym_to_demangled_hash_table (msym, objfile);
1283 /* Add the minimal symbols in the existing bunches to the objfile's official
1284 minimal symbol table. In most cases there is no minimal symbol table yet
1285 for this objfile, and the existing bunches are used to create one. Once
1286 in a while (for shared libraries for example), we add symbols (e.g. common
1287 symbols) to an existing objfile.
1289 Because of the way minimal symbols are collected, we generally have no way
1290 of knowing what source language applies to any particular minimal symbol.
1291 Specifically, we have no way of knowing if the minimal symbol comes from a
1292 C++ compilation unit or not. So for the sake of supporting cached
1293 demangled C++ names, we have no choice but to try and demangle each new one
1294 that comes in. If the demangling succeeds, then we assume it is a C++
1295 symbol and set the symbol's language and demangled name fields
1296 appropriately. Note that in order to avoid unnecessary demanglings, and
1297 allocating obstack space that subsequently can't be freed for the demangled
1298 names, we mark all newly added symbols with language_auto. After
1299 compaction of the minimal symbols, we go back and scan the entire minimal
1300 symbol table looking for these new symbols. For each new symbol we attempt
1301 to demangle it, and if successful, record it as a language_cplus symbol
1302 and cache the demangled form on the symbol obstack. Symbols which don't
1303 demangle are marked as language_unknown symbols, which inhibits future
1304 attempts to demangle them if we later add more minimal symbols. */
1307 minimal_symbol_reader::install ()
1311 struct msym_bunch *bunch;
1312 struct minimal_symbol *msymbols;
1315 if (m_objfile->per_bfd->minsyms_read)
1318 if (m_msym_count > 0)
1320 if (symtab_create_debug)
1322 fprintf_unfiltered (gdb_stdlog,
1323 "Installing %d minimal symbols of objfile %s.\n",
1324 m_msym_count, objfile_name (m_objfile));
1327 /* Allocate enough space in the obstack, into which we will gather the
1328 bunches of new and existing minimal symbols, sort them, and then
1329 compact out the duplicate entries. Once we have a final table,
1330 we will give back the excess space. */
1332 alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count + 1;
1333 obstack_blank (&m_objfile->per_bfd->storage_obstack,
1334 alloc_count * sizeof (struct minimal_symbol));
1335 msymbols = (struct minimal_symbol *)
1336 obstack_base (&m_objfile->per_bfd->storage_obstack);
1338 /* Copy in the existing minimal symbols, if there are any. */
1340 if (m_objfile->per_bfd->minimal_symbol_count)
1341 memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols,
1342 m_objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol));
1344 /* Walk through the list of minimal symbol bunches, adding each symbol
1345 to the new contiguous array of symbols. Note that we start with the
1346 current, possibly partially filled bunch (thus we use the current
1347 msym_bunch_index for the first bunch we copy over), and thereafter
1348 each bunch is full. */
1350 mcount = m_objfile->per_bfd->minimal_symbol_count;
1352 for (bunch = m_msym_bunch; bunch != NULL; bunch = bunch->next)
1354 for (bindex = 0; bindex < m_msym_bunch_index; bindex++, mcount++)
1355 msymbols[mcount] = bunch->contents[bindex];
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);
1369 obstack_blank_fast (&m_objfile->per_bfd->storage_obstack,
1370 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1371 msymbols = (struct minimal_symbol *)
1372 obstack_finish (&m_objfile->per_bfd->storage_obstack);
1374 /* We also terminate the minimal symbol table with a "null symbol",
1375 which is *not* included in the size of the table. This makes it
1376 easier to find the end of the table when we are handed a pointer
1377 to some symbol in the middle of it. Zero out the fields in the
1378 "null symbol" allocated at the end of the array. Note that the
1379 symbol count does *not* include this null symbol, which is why it
1380 is indexed by mcount and not mcount-1. */
1382 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1384 /* Attach the minimal symbol table to the specified objfile.
1385 The strings themselves are also located in the storage_obstack
1388 m_objfile->per_bfd->minimal_symbol_count = mcount;
1389 m_objfile->per_bfd->msymbols = msymbols;
1391 /* Now build the hash tables; we can't do this incrementally
1392 at an earlier point since we weren't finished with the obstack
1393 yet. (And if the msymbol obstack gets moved, all the internal
1394 pointers to other msymbols need to be adjusted.) */
1395 build_minimal_symbol_hash_tables (m_objfile);
1399 /* See minsyms.h. */
1402 terminate_minimal_symbol_table (struct objfile *objfile)
1404 if (! objfile->per_bfd->msymbols)
1405 objfile->per_bfd->msymbols = XOBNEW (&objfile->per_bfd->storage_obstack,
1409 struct minimal_symbol *m
1410 = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1412 memset (m, 0, sizeof (*m));
1413 /* Don't rely on these enumeration values being 0's. */
1414 MSYMBOL_TYPE (m) = mst_unknown;
1415 MSYMBOL_SET_LANGUAGE (m, language_unknown,
1416 &objfile->per_bfd->storage_obstack);
1420 /* Check if PC is in a shared library trampoline code stub.
1421 Return minimal symbol for the trampoline entry or NULL if PC is not
1422 in a trampoline code stub. */
1424 static struct minimal_symbol *
1425 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1427 bound_minimal_symbol msymbol
1428 = lookup_minimal_symbol_by_pc_section (pc, NULL,
1429 lookup_msym_prefer::TRAMPOLINE);
1431 if (msymbol.minsym != NULL
1432 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1433 return msymbol.minsym;
1437 /* If PC is in a shared library trampoline code stub, return the
1438 address of the `real' function belonging to the stub.
1439 Return 0 if PC is not in a trampoline code stub or if the real
1440 function is not found in the minimal symbol table.
1442 We may fail to find the right function if a function with the
1443 same name is defined in more than one shared library, but this
1444 is considered bad programming style. We could return 0 if we find
1445 a duplicate function in case this matters someday. */
1448 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1450 struct objfile *objfile;
1451 struct minimal_symbol *msymbol;
1452 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1454 if (tsymbol != NULL)
1456 ALL_MSYMBOLS (objfile, msymbol)
1458 /* Also handle minimal symbols pointing to function descriptors. */
1459 if ((MSYMBOL_TYPE (msymbol) == mst_text
1460 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
1461 || MSYMBOL_TYPE (msymbol) == mst_data
1462 || MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc)
1463 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1464 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1468 /* Ignore data symbols that are not function
1470 if (msymbol_is_function (objfile, msymbol, &func))
1478 /* See minsyms.h. */
1481 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1485 struct obj_section *obj_section;
1487 struct minimal_symbol *msymbol;
1489 gdb_assert (minsym.minsym != NULL);
1491 /* If the minimal symbol has a size, use it. Otherwise use the
1492 lesser of the next minimal symbol in the same section, or the end
1493 of the section, as the end of the function. */
1495 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1496 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1498 /* Step over other symbols at this same address, and symbols in
1499 other sections, to find the next symbol in this section with a
1500 different address. */
1502 msymbol = minsym.minsym;
1503 section = MSYMBOL_SECTION (msymbol);
1504 for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1506 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1507 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1508 && MSYMBOL_SECTION (msymbol + i) == section)
1512 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1513 if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1514 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1515 < obj_section_endaddr (obj_section)))
1516 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
1518 /* We got the start address from the last msymbol in the objfile.
1519 So the end address is the end of the section. */
1520 result = obj_section_endaddr (obj_section);