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);
76 CORE_ADDR pc = gdbarch_convert_from_func_ptr_addr (gdbarch, msym_addr,
80 if (func_address_p != NULL)
87 if (func_address_p != NULL)
88 *func_address_p = msym_addr;
93 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
94 At the end, copy them all into one newly allocated location on an objfile's
95 per-BFD storage obstack. */
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 auto &vec = objfile->per_bfd->demangled_hash_languages;
163 auto it = std::lower_bound (vec.begin (), vec.end (),
164 MSYMBOL_LANGUAGE (sym));
165 if (it == vec.end () || *it != MSYMBOL_LANGUAGE (sym))
166 vec.insert (it, MSYMBOL_LANGUAGE (sym));
168 struct minimal_symbol **table
169 = objfile->per_bfd->msymbol_demangled_hash;
170 unsigned int hash_index = hash % MINIMAL_SYMBOL_HASH_SIZE;
171 sym->demangled_hash_next = table[hash_index];
172 table[hash_index] = sym;
176 /* Worker object for lookup_minimal_symbol. Stores temporary results
177 while walking the symbol tables. */
179 struct found_minimal_symbols
181 /* External symbols are best. */
182 bound_minimal_symbol external_symbol {};
184 /* File-local symbols are next best. */
185 bound_minimal_symbol file_symbol {};
187 /* Symbols for shared library trampolines are next best. */
188 bound_minimal_symbol trampoline_symbol {};
190 /* Called when a symbol name matches. Check if the minsym is a
191 better type than what we had already found, and record it in one
192 of the members fields if so. Returns true if we collected the
193 real symbol, in which case we can stop searching. */
194 bool maybe_collect (const char *sfile, objfile *objf,
195 minimal_symbol *msymbol);
198 /* See declaration above. */
201 found_minimal_symbols::maybe_collect (const char *sfile,
202 struct objfile *objfile,
203 minimal_symbol *msymbol)
205 switch (MSYMBOL_TYPE (msymbol))
211 || filename_cmp (msymbol->filename, sfile) == 0)
213 file_symbol.minsym = msymbol;
214 file_symbol.objfile = objfile;
218 case mst_solib_trampoline:
220 /* If a trampoline symbol is found, we prefer to keep
221 looking for the *real* symbol. If the actual symbol
222 is not found, then we'll use the trampoline
224 if (trampoline_symbol.minsym == NULL)
226 trampoline_symbol.minsym = msymbol;
227 trampoline_symbol.objfile = objfile;
233 external_symbol.minsym = msymbol;
234 external_symbol.objfile = objfile;
235 /* We have the real symbol. No use looking further. */
243 /* Walk the mangled name hash table, and pass each symbol whose name
244 matches LOOKUP_NAME according to NAMECMP to FOUND. */
247 lookup_minimal_symbol_mangled (const char *lookup_name,
249 struct objfile *objfile,
250 struct minimal_symbol **table,
252 int (*namecmp) (const char *, const char *),
253 found_minimal_symbols &found)
255 for (minimal_symbol *msymbol = table[hash];
257 msymbol = msymbol->hash_next)
259 const char *symbol_name = MSYMBOL_LINKAGE_NAME (msymbol);
261 if (namecmp (symbol_name, lookup_name) == 0
262 && found.maybe_collect (sfile, objfile, msymbol))
267 /* Walk the demangled name hash table, and pass each symbol whose name
268 matches LOOKUP_NAME according to MATCHER to FOUND. */
271 lookup_minimal_symbol_demangled (const lookup_name_info &lookup_name,
273 struct objfile *objfile,
274 struct minimal_symbol **table,
276 symbol_name_matcher_ftype *matcher,
277 found_minimal_symbols &found)
279 for (minimal_symbol *msymbol = table[hash];
281 msymbol = msymbol->demangled_hash_next)
283 const char *symbol_name = MSYMBOL_SEARCH_NAME (msymbol);
285 if (matcher (symbol_name, lookup_name, NULL)
286 && found.maybe_collect (sfile, objfile, msymbol))
291 /* Look through all the current minimal symbol tables and find the
292 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
293 the search to that objfile. If SFILE is non-NULL, the only file-scope
294 symbols considered will be from that source file (global symbols are
295 still preferred). Returns a pointer to the minimal symbol that
296 matches, or NULL if no match is found.
298 Note: One instance where there may be duplicate minimal symbols with
299 the same name is when the symbol tables for a shared library and the
300 symbol tables for an executable contain global symbols with the same
301 names (the dynamic linker deals with the duplication).
303 It's also possible to have minimal symbols with different mangled
304 names, but identical demangled names. For example, the GNU C++ v3
305 ABI requires the generation of two (or perhaps three) copies of
306 constructor functions --- "in-charge", "not-in-charge", and
307 "allocate" copies; destructors may be duplicated as well.
308 Obviously, there must be distinct mangled names for each of these,
309 but the demangled names are all the same: S::S or S::~S. */
311 struct bound_minimal_symbol
312 lookup_minimal_symbol (const char *name, const char *sfile,
313 struct objfile *objf)
315 struct objfile *objfile;
316 found_minimal_symbols found;
318 unsigned int mangled_hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
321 = (case_sensitivity == case_sensitive_on
326 sfile = lbasename (sfile);
328 lookup_name_info lookup_name (name, symbol_name_match_type::FULL);
330 for (objfile = object_files;
331 objfile != NULL && found.external_symbol.minsym == NULL;
332 objfile = objfile->next)
334 if (objf == NULL || objf == objfile
335 || objf == objfile->separate_debug_objfile_backlink)
337 if (symbol_lookup_debug)
339 fprintf_unfiltered (gdb_stdlog,
340 "lookup_minimal_symbol (%s, %s, %s)\n",
341 name, sfile != NULL ? sfile : "NULL",
342 objfile_debug_name (objfile));
345 /* Do two passes: the first over the ordinary hash table,
346 and the second over the demangled hash table. */
347 lookup_minimal_symbol_mangled (name, sfile, objfile,
348 objfile->per_bfd->msymbol_hash,
349 mangled_hash, mangled_cmp, found);
351 /* If not found, try the demangled hash table. */
352 if (found.external_symbol.minsym == NULL)
354 /* Once for each language in the demangled hash names
355 table (usually just zero or one languages). */
356 for (auto lang : objfile->per_bfd->demangled_hash_languages)
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 (auto lang : objf->per_bfd->demangled_hash_languages)
501 const language_defn *lang_def = language_def (lang);
502 symbol_name_matcher_ftype *name_match
503 = get_symbol_name_matcher (lang_def, lookup_name);
506 = lookup_name.search_name_hash (lang) % MINIMAL_SYMBOL_HASH_SIZE;
507 for (minimal_symbol *iter = objf->per_bfd->msymbol_demangled_hash[hash];
509 iter = iter->demangled_hash_next)
510 if (name_match (MSYMBOL_SEARCH_NAME (iter), lookup_name, NULL))
518 struct bound_minimal_symbol
519 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
521 struct objfile *objfile;
522 struct minimal_symbol *msymbol;
523 struct bound_minimal_symbol found_symbol = { NULL, NULL };
524 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
526 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
528 for (objfile = object_files;
529 objfile != NULL && found_symbol.minsym == NULL;
530 objfile = objfile->next)
532 if (objf == NULL || objf == objfile
533 || objf == objfile->separate_debug_objfile_backlink)
535 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
536 msymbol != NULL && found_symbol.minsym == NULL;
537 msymbol = msymbol->hash_next)
539 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
540 (MSYMBOL_TYPE (msymbol) == mst_text
541 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
542 || MSYMBOL_TYPE (msymbol) == mst_file_text))
544 switch (MSYMBOL_TYPE (msymbol))
547 found_file_symbol.minsym = msymbol;
548 found_file_symbol.objfile = objfile;
551 found_symbol.minsym = msymbol;
552 found_symbol.objfile = objfile;
559 /* External symbols are best. */
560 if (found_symbol.minsym)
563 /* File-local symbols are next best. */
564 return found_file_symbol;
569 struct minimal_symbol *
570 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
571 struct objfile *objf)
573 struct objfile *objfile;
574 struct minimal_symbol *msymbol;
576 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
578 for (objfile = object_files;
580 objfile = objfile->next)
582 if (objf == NULL || objf == objfile
583 || objf == objfile->separate_debug_objfile_backlink)
585 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
587 msymbol = msymbol->hash_next)
589 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
590 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
601 struct bound_minimal_symbol
602 lookup_minimal_symbol_solib_trampoline (const char *name,
603 struct objfile *objf)
605 struct objfile *objfile;
606 struct minimal_symbol *msymbol;
607 struct bound_minimal_symbol found_symbol = { NULL, NULL };
609 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
611 for (objfile = object_files;
613 objfile = objfile->next)
615 if (objf == NULL || objf == objfile
616 || objf == objfile->separate_debug_objfile_backlink)
618 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
620 msymbol = msymbol->hash_next)
622 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
623 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
625 found_symbol.objfile = objfile;
626 found_symbol.minsym = msymbol;
636 /* A helper function that makes *PC section-relative. This searches
637 the sections of OBJFILE and if *PC is in a section, it subtracts
638 the section offset and returns true. Otherwise it returns
642 frob_address (struct objfile *objfile, CORE_ADDR *pc)
644 struct obj_section *iter;
646 ALL_OBJFILE_OSECTIONS (objfile, iter)
648 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
650 *pc -= obj_section_offset (iter);
658 /* Search through the minimal symbol table for each objfile and find
659 the symbol whose address is the largest address that is still less
660 than or equal to PC, and matches SECTION (which is not NULL).
661 Returns a pointer to the minimal symbol if such a symbol is found,
662 or NULL if PC is not in a suitable range.
663 Note that we need to look through ALL the minimal symbol tables
664 before deciding on the symbol that comes closest to the specified PC.
665 This is because objfiles can overlap, for example objfile A has .text
666 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
669 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
670 there are text and trampoline symbols at the same address.
671 Otherwise prefer mst_text symbols. */
674 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *section,
675 lookup_msym_prefer prefer)
680 struct objfile *objfile;
681 struct minimal_symbol *msymbol;
682 struct minimal_symbol *best_symbol = NULL;
683 struct objfile *best_objfile = NULL;
684 struct bound_minimal_symbol result;
685 enum minimal_symbol_type want_type;
689 section = find_pc_section (pc_in);
696 case lookup_msym_prefer::TEXT:
697 want_type = mst_text;
699 case lookup_msym_prefer::TRAMPOLINE:
700 want_type = mst_solib_trampoline;
702 case lookup_msym_prefer::GNU_IFUNC:
703 want_type = mst_text_gnu_ifunc;
707 /* We can not require the symbol found to be in section, because
708 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
709 symbol - but find_pc_section won't return an absolute section and
710 hence the code below would skip over absolute symbols. We can
711 still take advantage of the call to find_pc_section, though - the
712 object file still must match. In case we have separate debug
713 files, search both the file and its separate debug file. There's
714 no telling which one will have the minimal symbols. */
716 gdb_assert (section != NULL);
718 for (objfile = section->objfile;
720 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
722 CORE_ADDR pc = pc_in;
724 /* If this objfile has a minimal symbol table, go search it using
725 a binary search. Note that a minimal symbol table always consists
726 of at least two symbols, a "real" symbol and the terminating
727 "null symbol". If there are no real symbols, then there is no
728 minimal symbol table at all. */
730 if (objfile->per_bfd->minimal_symbol_count > 0)
732 int best_zero_sized = -1;
734 msymbol = objfile->per_bfd->msymbols;
736 hi = objfile->per_bfd->minimal_symbol_count - 1;
738 /* This code assumes that the minimal symbols are sorted by
739 ascending address values. If the pc value is greater than or
740 equal to the first symbol's address, then some symbol in this
741 minimal symbol table is a suitable candidate for being the
742 "best" symbol. This includes the last real symbol, for cases
743 where the pc value is larger than any address in this vector.
745 By iterating until the address associated with the current
746 hi index (the endpoint of the test interval) is less than
747 or equal to the desired pc value, we accomplish two things:
748 (1) the case where the pc value is larger than any minimal
749 symbol address is trivially solved, (2) the address associated
750 with the hi index is always the one we want when the interation
751 terminates. In essence, we are iterating the test interval
752 down until the pc value is pushed out of it from the high end.
754 Warning: this code is trickier than it would appear at first. */
756 if (frob_address (objfile, &pc)
757 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
759 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
761 /* pc is still strictly less than highest address. */
762 /* Note "new" will always be >= lo. */
763 newobj = (lo + hi) / 2;
764 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
775 /* If we have multiple symbols at the same address, we want
776 hi to point to the last one. That way we can find the
777 right symbol if it has an index greater than hi. */
778 while (hi < objfile->per_bfd->minimal_symbol_count - 1
779 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
780 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
783 /* Skip various undesirable symbols. */
786 /* Skip any absolute symbols. This is apparently
787 what adb and dbx do, and is needed for the CM-5.
788 There are two known possible problems: (1) on
789 ELF, apparently end, edata, etc. are absolute.
790 Not sure ignoring them here is a big deal, but if
791 we want to use them, the fix would go in
792 elfread.c. (2) I think shared library entry
793 points on the NeXT are absolute. If we want
794 special handling for this it probably should be
795 triggered by a special mst_abs_or_lib or some
798 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
804 /* If SECTION was specified, skip any symbol from
807 /* Some types of debug info, such as COFF,
808 don't fill the bfd_section member, so don't
809 throw away symbols on those platforms. */
810 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
811 && (!matching_obj_sections
812 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
819 /* If we are looking for a trampoline and this is a
820 text symbol, or the other way around, check the
821 preceding symbol too. If they are otherwise
822 identical prefer that one. */
824 && MSYMBOL_TYPE (&msymbol[hi]) != want_type
825 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
826 && (MSYMBOL_SIZE (&msymbol[hi])
827 == MSYMBOL_SIZE (&msymbol[hi - 1]))
828 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
829 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
830 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
831 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
837 /* If the minimal symbol has a zero size, save it
838 but keep scanning backwards looking for one with
839 a non-zero size. A zero size may mean that the
840 symbol isn't an object or function (e.g. a
841 label), or it may just mean that the size was not
843 if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
845 if (best_zero_sized == -1)
846 best_zero_sized = hi;
851 /* If we are past the end of the current symbol, try
852 the previous symbol if it has a larger overlapping
853 size. This happens on i686-pc-linux-gnu with glibc;
854 the nocancel variants of system calls are inside
855 the cancellable variants, but both have sizes. */
857 && MSYMBOL_SIZE (&msymbol[hi]) != 0
858 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
859 + MSYMBOL_SIZE (&msymbol[hi]))
860 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
861 + MSYMBOL_SIZE (&msymbol[hi - 1])))
867 /* Otherwise, this symbol must be as good as we're going
872 /* If HI has a zero size, and best_zero_sized is set,
873 then we had two or more zero-sized symbols; prefer
874 the first one we found (which may have a higher
875 address). Also, if we ran off the end, be sure
877 if (best_zero_sized != -1
878 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
879 hi = best_zero_sized;
881 /* If the minimal symbol has a non-zero size, and this
882 PC appears to be outside the symbol's contents, then
883 refuse to use this symbol. If we found a zero-sized
884 symbol with an address greater than this symbol's,
885 use that instead. We assume that if symbols have
886 specified sizes, they do not overlap. */
889 && MSYMBOL_SIZE (&msymbol[hi]) != 0
890 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
891 + MSYMBOL_SIZE (&msymbol[hi])))
893 if (best_zero_sized != -1)
894 hi = best_zero_sized;
896 /* Go on to the next object file. */
900 /* The minimal symbol indexed by hi now is the best one in this
901 objfile's minimal symbol table. See if it is the best one
905 && ((best_symbol == NULL) ||
906 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
907 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
909 best_symbol = &msymbol[hi];
910 best_objfile = objfile;
916 result.minsym = best_symbol;
917 result.objfile = best_objfile;
923 struct bound_minimal_symbol
924 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
926 return lookup_minimal_symbol_by_pc_section (pc, NULL);
929 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
932 in_gnu_ifunc_stub (CORE_ADDR pc)
934 bound_minimal_symbol msymbol
935 = lookup_minimal_symbol_by_pc_section (pc, NULL,
936 lookup_msym_prefer::GNU_IFUNC);
937 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
940 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
943 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
945 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
946 "the ELF support compiled in."),
947 paddress (gdbarch, pc));
950 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
953 stub_gnu_ifunc_resolve_name (const char *function_name,
954 CORE_ADDR *function_address_p)
956 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
957 "the ELF support compiled in."),
961 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
964 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
966 internal_error (__FILE__, __LINE__,
967 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
970 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
973 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
975 internal_error (__FILE__, __LINE__,
976 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
979 /* See elf_gnu_ifunc_fns for its real implementation. */
981 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
983 stub_gnu_ifunc_resolve_addr,
984 stub_gnu_ifunc_resolve_name,
985 stub_gnu_ifunc_resolver_stop,
986 stub_gnu_ifunc_resolver_return_stop,
989 /* A placeholder for &elf_gnu_ifunc_fns. */
991 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
995 /* Return leading symbol character for a BFD. If BFD is NULL,
996 return the leading symbol character from the main objfile. */
999 get_symbol_leading_char (bfd *abfd)
1002 return bfd_get_symbol_leading_char (abfd);
1003 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
1004 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
1008 /* See minsyms.h. */
1010 minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj)
1012 m_msym_bunch (NULL),
1013 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1014 first call to save a minimal symbol to allocate the memory for
1016 m_msym_bunch_index (BUNCH_SIZE),
1021 /* Discard the currently collected minimal symbols, if any. If we wish
1022 to save them for later use, we must have already copied them somewhere
1023 else before calling this function.
1025 FIXME: We could allocate the minimal symbol bunches on their own
1026 obstack and then simply blow the obstack away when we are done with
1027 it. Is it worth the extra trouble though? */
1029 minimal_symbol_reader::~minimal_symbol_reader ()
1031 struct msym_bunch *next;
1033 while (m_msym_bunch != NULL)
1035 next = m_msym_bunch->next;
1036 xfree (m_msym_bunch);
1037 m_msym_bunch = next;
1041 /* See minsyms.h. */
1044 minimal_symbol_reader::record (const char *name, CORE_ADDR address,
1045 enum minimal_symbol_type ms_type)
1052 case mst_text_gnu_ifunc:
1054 case mst_solib_trampoline:
1055 section = SECT_OFF_TEXT (m_objfile);
1058 case mst_data_gnu_ifunc:
1060 section = SECT_OFF_DATA (m_objfile);
1064 section = SECT_OFF_BSS (m_objfile);
1070 record_with_info (name, address, ms_type, section);
1073 /* See minsyms.h. */
1075 struct minimal_symbol *
1076 minimal_symbol_reader::record_full (const char *name, int name_len,
1077 bool copy_name, CORE_ADDR address,
1078 enum minimal_symbol_type ms_type,
1081 struct msym_bunch *newobj;
1082 struct minimal_symbol *msymbol;
1084 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1085 the minimal symbols, because if there is also another symbol
1086 at the same address (e.g. the first function of the file),
1087 lookup_minimal_symbol_by_pc would have no way of getting the
1089 if (ms_type == mst_file_text && name[0] == 'g'
1090 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
1091 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
1094 /* It's safe to strip the leading char here once, since the name
1095 is also stored stripped in the minimal symbol table. */
1096 if (name[0] == get_symbol_leading_char (m_objfile->obfd))
1102 if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
1105 if (m_msym_bunch_index == BUNCH_SIZE)
1107 newobj = XCNEW (struct msym_bunch);
1108 m_msym_bunch_index = 0;
1109 newobj->next = m_msym_bunch;
1110 m_msym_bunch = newobj;
1112 msymbol = &m_msym_bunch->contents[m_msym_bunch_index];
1113 MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
1114 &m_objfile->per_bfd->storage_obstack);
1115 MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, m_objfile);
1117 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1118 MSYMBOL_SECTION (msymbol) = section;
1120 MSYMBOL_TYPE (msymbol) = ms_type;
1121 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
1122 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
1123 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
1124 as it would also set the has_size flag. */
1127 /* The hash pointers must be cleared! If they're not,
1128 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
1129 msymbol->hash_next = NULL;
1130 msymbol->demangled_hash_next = NULL;
1132 /* If we already read minimal symbols for this objfile, then don't
1133 ever allocate a new one. */
1134 if (!m_objfile->per_bfd->minsyms_read)
1136 m_msym_bunch_index++;
1137 m_objfile->per_bfd->n_minsyms++;
1143 /* Compare two minimal symbols by address and return a signed result based
1144 on unsigned comparisons, so that we sort into unsigned numeric order.
1145 Within groups with the same address, sort by name. */
1148 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1150 const struct minimal_symbol *fn1;
1151 const struct minimal_symbol *fn2;
1153 fn1 = (const struct minimal_symbol *) fn1p;
1154 fn2 = (const struct minimal_symbol *) fn2p;
1156 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1158 return (-1); /* addr 1 is less than addr 2. */
1160 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1162 return (1); /* addr 1 is greater than addr 2. */
1165 /* addrs are equal: sort by name */
1167 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1168 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1170 if (name1 && name2) /* both have names */
1171 return strcmp (name1, name2);
1173 return 1; /* fn1 has no name, so it is "less". */
1174 else if (name1) /* fn2 has no name, so it is "less". */
1177 return (0); /* Neither has a name, so they're equal. */
1181 /* Compact duplicate entries out of a minimal symbol table by walking
1182 through the table and compacting out entries with duplicate addresses
1183 and matching names. Return the number of entries remaining.
1185 On entry, the table resides between msymbol[0] and msymbol[mcount].
1186 On exit, it resides between msymbol[0] and msymbol[result_count].
1188 When files contain multiple sources of symbol information, it is
1189 possible for the minimal symbol table to contain many duplicate entries.
1190 As an example, SVR4 systems use ELF formatted object files, which
1191 usually contain at least two different types of symbol tables (a
1192 standard ELF one and a smaller dynamic linking table), as well as
1193 DWARF debugging information for files compiled with -g.
1195 Without compacting, the minimal symbol table for gdb itself contains
1196 over a 1000 duplicates, about a third of the total table size. Aside
1197 from the potential trap of not noticing that two successive entries
1198 identify the same location, this duplication impacts the time required
1199 to linearly scan the table, which is done in a number of places. So we
1200 just do one linear scan here and toss out the duplicates.
1202 Note that we are not concerned here about recovering the space that
1203 is potentially freed up, because the strings themselves are allocated
1204 on the storage_obstack, and will get automatically freed when the symbol
1205 table is freed. The caller can free up the unused minimal symbols at
1206 the end of the compacted region if their allocation strategy allows it.
1208 Also note we only go up to the next to last entry within the loop
1209 and then copy the last entry explicitly after the loop terminates.
1211 Since the different sources of information for each symbol may
1212 have different levels of "completeness", we may have duplicates
1213 that have one entry with type "mst_unknown" and the other with a
1214 known type. So if the one we are leaving alone has type mst_unknown,
1215 overwrite its type with the type from the one we are compacting out. */
1218 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1219 struct objfile *objfile)
1221 struct minimal_symbol *copyfrom;
1222 struct minimal_symbol *copyto;
1226 copyfrom = copyto = msymbol;
1227 while (copyfrom < msymbol + mcount - 1)
1229 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1230 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1231 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1232 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1233 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1235 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1237 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1242 *copyto++ = *copyfrom++;
1244 *copyto++ = *copyfrom++;
1245 mcount = copyto - msymbol;
1250 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1251 after compacting or sorting the table since the entries move around
1252 thus causing the internal minimal_symbol pointers to become jumbled. */
1255 build_minimal_symbol_hash_tables (struct objfile *objfile)
1258 struct minimal_symbol *msym;
1260 /* Clear the hash tables. */
1261 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1263 objfile->per_bfd->msymbol_hash[i] = 0;
1264 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1267 /* Now, (re)insert the actual entries. */
1268 for ((i = objfile->per_bfd->minimal_symbol_count,
1269 msym = objfile->per_bfd->msymbols);
1273 msym->hash_next = 0;
1274 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1276 msym->demangled_hash_next = 0;
1277 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1278 add_minsym_to_demangled_hash_table (msym, objfile);
1282 /* Add the minimal symbols in the existing bunches to the objfile's official
1283 minimal symbol table. In most cases there is no minimal symbol table yet
1284 for this objfile, and the existing bunches are used to create one. Once
1285 in a while (for shared libraries for example), we add symbols (e.g. common
1286 symbols) to an existing objfile.
1288 Because of the way minimal symbols are collected, we generally have no way
1289 of knowing what source language applies to any particular minimal symbol.
1290 Specifically, we have no way of knowing if the minimal symbol comes from a
1291 C++ compilation unit or not. So for the sake of supporting cached
1292 demangled C++ names, we have no choice but to try and demangle each new one
1293 that comes in. If the demangling succeeds, then we assume it is a C++
1294 symbol and set the symbol's language and demangled name fields
1295 appropriately. Note that in order to avoid unnecessary demanglings, and
1296 allocating obstack space that subsequently can't be freed for the demangled
1297 names, we mark all newly added symbols with language_auto. After
1298 compaction of the minimal symbols, we go back and scan the entire minimal
1299 symbol table looking for these new symbols. For each new symbol we attempt
1300 to demangle it, and if successful, record it as a language_cplus symbol
1301 and cache the demangled form on the symbol obstack. Symbols which don't
1302 demangle are marked as language_unknown symbols, which inhibits future
1303 attempts to demangle them if we later add more minimal symbols. */
1306 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 in the obstack, into which we will gather the
1327 bunches of new and existing minimal symbols, sort them, and then
1328 compact out the duplicate entries. Once we have a final table,
1329 we will give back the excess space. */
1331 alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count + 1;
1332 obstack_blank (&m_objfile->per_bfd->storage_obstack,
1333 alloc_count * sizeof (struct minimal_symbol));
1334 msymbols = (struct minimal_symbol *)
1335 obstack_base (&m_objfile->per_bfd->storage_obstack);
1337 /* Copy in the existing minimal symbols, if there are any. */
1339 if (m_objfile->per_bfd->minimal_symbol_count)
1340 memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols,
1341 m_objfile->per_bfd->minimal_symbol_count * 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 for (bindex = 0; bindex < m_msym_bunch_index; bindex++, mcount++)
1354 msymbols[mcount] = bunch->contents[bindex];
1355 m_msym_bunch_index = BUNCH_SIZE;
1358 /* Sort the minimal symbols by address. */
1360 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1361 compare_minimal_symbols);
1363 /* Compact out any duplicates, and free up whatever space we are
1366 mcount = compact_minimal_symbols (msymbols, mcount, m_objfile);
1368 obstack_blank_fast (&m_objfile->per_bfd->storage_obstack,
1369 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1370 msymbols = (struct minimal_symbol *)
1371 obstack_finish (&m_objfile->per_bfd->storage_obstack);
1373 /* We also terminate the minimal symbol table with a "null symbol",
1374 which is *not* included in the size of the table. This makes it
1375 easier to find the end of the table when we are handed a pointer
1376 to some symbol in the middle of it. Zero out the fields in the
1377 "null symbol" allocated at the end of the array. Note that the
1378 symbol count does *not* include this null symbol, which is why it
1379 is indexed by mcount and not mcount-1. */
1381 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1383 /* Attach the minimal symbol table to the specified objfile.
1384 The strings themselves are also located in the storage_obstack
1387 m_objfile->per_bfd->minimal_symbol_count = mcount;
1388 m_objfile->per_bfd->msymbols = msymbols;
1390 /* Now build the hash tables; we can't do this incrementally
1391 at an earlier point since we weren't finished with the obstack
1392 yet. (And if the msymbol obstack gets moved, all the internal
1393 pointers to other msymbols need to be adjusted.) */
1394 build_minimal_symbol_hash_tables (m_objfile);
1398 /* See minsyms.h. */
1401 terminate_minimal_symbol_table (struct objfile *objfile)
1403 if (! objfile->per_bfd->msymbols)
1404 objfile->per_bfd->msymbols = XOBNEW (&objfile->per_bfd->storage_obstack,
1408 struct minimal_symbol *m
1409 = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1411 memset (m, 0, sizeof (*m));
1412 /* Don't rely on these enumeration values being 0's. */
1413 MSYMBOL_TYPE (m) = mst_unknown;
1414 MSYMBOL_SET_LANGUAGE (m, language_unknown,
1415 &objfile->per_bfd->storage_obstack);
1419 /* Check if PC is in a shared library trampoline code stub.
1420 Return minimal symbol for the trampoline entry or NULL if PC is not
1421 in a trampoline code stub. */
1423 static struct minimal_symbol *
1424 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1426 bound_minimal_symbol msymbol
1427 = lookup_minimal_symbol_by_pc_section (pc, NULL,
1428 lookup_msym_prefer::TRAMPOLINE);
1430 if (msymbol.minsym != NULL
1431 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1432 return msymbol.minsym;
1436 /* If PC is in a shared library trampoline code stub, return the
1437 address of the `real' function belonging to the stub.
1438 Return 0 if PC is not in a trampoline code stub or if the real
1439 function is not found in the minimal symbol table.
1441 We may fail to find the right function if a function with the
1442 same name is defined in more than one shared library, but this
1443 is considered bad programming style. We could return 0 if we find
1444 a duplicate function in case this matters someday. */
1447 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1449 struct objfile *objfile;
1450 struct minimal_symbol *msymbol;
1451 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1453 if (tsymbol != NULL)
1455 ALL_MSYMBOLS (objfile, msymbol)
1457 /* Also handle minimal symbols pointing to function descriptors. */
1458 if ((MSYMBOL_TYPE (msymbol) == mst_text
1459 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
1460 || MSYMBOL_TYPE (msymbol) == mst_data
1461 || MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc)
1462 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1463 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1467 /* Ignore data symbols that are not function
1469 if (msymbol_is_function (objfile, msymbol, &func))
1477 /* See minsyms.h. */
1480 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1484 struct obj_section *obj_section;
1486 struct minimal_symbol *msymbol;
1488 gdb_assert (minsym.minsym != NULL);
1490 /* If the minimal symbol has a size, use it. Otherwise use the
1491 lesser of the next minimal symbol in the same section, or the end
1492 of the section, as the end of the function. */
1494 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1495 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1497 /* Step over other symbols at this same address, and symbols in
1498 other sections, to find the next symbol in this section with a
1499 different address. */
1501 msymbol = minsym.minsym;
1502 section = MSYMBOL_SECTION (msymbol);
1503 for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1505 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1506 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1507 && MSYMBOL_SECTION (msymbol + i) == section)
1511 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1512 if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1513 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1514 < obj_section_endaddr (obj_section)))
1515 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
1517 /* We got the start address from the last msymbol in the objfile.
1518 So the end address is the end of the section. */
1519 result = obj_section_endaddr (obj_section);