1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2017 Free Software Foundation, Inc.
3 Contributed by Cygnus Support, using pieces from other GDB modules.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 /* This file contains support routines for creating, manipulating, and
22 destroying minimal symbol tables.
24 Minimal symbol tables are used to hold some very basic information about
25 all defined global symbols (text, data, bss, abs, etc). The only two
26 required pieces of information are the symbol's name and the address
27 associated with that symbol.
29 In many cases, even if a file was compiled with no special options for
30 debugging at all, as long as was not stripped it will contain sufficient
31 information to build useful minimal symbol tables using this structure.
33 Even when a file contains enough debugging information to build a full
34 symbol table, these minimal symbols are still useful for quickly mapping
35 between names and addresses, and vice versa. They are also sometimes used
36 to figure out what full symbol table entries need to be read in. */
43 #include "filenames.h"
50 #include "cp-support.h"
52 #include "cli/cli-utils.h"
55 #include "safe-ctype.h"
60 msymbol_is_function (struct objfile *objfile, minimal_symbol *minsym,
61 CORE_ADDR *func_address_p)
63 CORE_ADDR msym_addr = MSYMBOL_VALUE_ADDRESS (objfile, minsym);
67 case mst_slot_got_plt:
74 struct gdbarch *gdbarch = get_objfile_arch (objfile);
75 CORE_ADDR pc = gdbarch_convert_from_func_ptr_addr (gdbarch, msym_addr,
79 if (func_address_p != NULL)
86 if (func_address_p != NULL)
87 *func_address_p = msym_addr;
92 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
93 At the end, copy them all into one newly allocated location on an objfile's
94 per-BFD storage obstack. */
96 #define BUNCH_SIZE 127
100 struct msym_bunch *next;
101 struct minimal_symbol contents[BUNCH_SIZE];
107 msymbol_hash_iw (const char *string)
109 unsigned int hash = 0;
111 while (*string && *string != '(')
113 string = skip_spaces (string);
114 if (*string && *string != '(')
116 hash = SYMBOL_HASH_NEXT (hash, *string);
126 msymbol_hash (const char *string)
128 unsigned int hash = 0;
130 for (; *string; ++string)
131 hash = SYMBOL_HASH_NEXT (hash, *string);
135 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
137 add_minsym_to_hash_table (struct minimal_symbol *sym,
138 struct minimal_symbol **table)
140 if (sym->hash_next == NULL)
143 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
145 sym->hash_next = table[hash];
150 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
153 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
154 struct objfile *objfile)
156 if (sym->demangled_hash_next == NULL)
158 unsigned int hash = search_name_hash (MSYMBOL_LANGUAGE (sym),
159 MSYMBOL_SEARCH_NAME (sym));
161 auto &vec = objfile->per_bfd->demangled_hash_languages;
162 auto it = std::lower_bound (vec.begin (), vec.end (),
163 MSYMBOL_LANGUAGE (sym));
164 if (it == vec.end () || *it != MSYMBOL_LANGUAGE (sym))
165 vec.insert (it, MSYMBOL_LANGUAGE (sym));
167 struct minimal_symbol **table
168 = objfile->per_bfd->msymbol_demangled_hash;
169 unsigned int hash_index = hash % MINIMAL_SYMBOL_HASH_SIZE;
170 sym->demangled_hash_next = table[hash_index];
171 table[hash_index] = sym;
175 /* Worker object for lookup_minimal_symbol. Stores temporary results
176 while walking the symbol tables. */
178 struct found_minimal_symbols
180 /* External symbols are best. */
181 bound_minimal_symbol external_symbol {};
183 /* File-local symbols are next best. */
184 bound_minimal_symbol file_symbol {};
186 /* Symbols for shared library trampolines are next best. */
187 bound_minimal_symbol trampoline_symbol {};
189 /* Called when a symbol name matches. Check if the minsym is a
190 better type than what we had already found, and record it in one
191 of the members fields if so. Returns true if we collected the
192 real symbol, in which case we can stop searching. */
193 bool maybe_collect (const char *sfile, objfile *objf,
194 minimal_symbol *msymbol);
197 /* See declaration above. */
200 found_minimal_symbols::maybe_collect (const char *sfile,
201 struct objfile *objfile,
202 minimal_symbol *msymbol)
204 switch (MSYMBOL_TYPE (msymbol))
210 || filename_cmp (msymbol->filename, sfile) == 0)
212 file_symbol.minsym = msymbol;
213 file_symbol.objfile = objfile;
217 case mst_solib_trampoline:
219 /* If a trampoline symbol is found, we prefer to keep
220 looking for the *real* symbol. If the actual symbol
221 is not found, then we'll use the trampoline
223 if (trampoline_symbol.minsym == NULL)
225 trampoline_symbol.minsym = msymbol;
226 trampoline_symbol.objfile = objfile;
232 external_symbol.minsym = msymbol;
233 external_symbol.objfile = objfile;
234 /* We have the real symbol. No use looking further. */
242 /* Walk the mangled name hash table, and pass each symbol whose name
243 matches LOOKUP_NAME according to NAMECMP to FOUND. */
246 lookup_minimal_symbol_mangled (const char *lookup_name,
248 struct objfile *objfile,
249 struct minimal_symbol **table,
251 int (*namecmp) (const char *, const char *),
252 found_minimal_symbols &found)
254 for (minimal_symbol *msymbol = table[hash];
256 msymbol = msymbol->hash_next)
258 const char *symbol_name = MSYMBOL_LINKAGE_NAME (msymbol);
260 if (namecmp (symbol_name, lookup_name) == 0
261 && found.maybe_collect (sfile, objfile, msymbol))
266 /* Walk the demangled name hash table, and pass each symbol whose name
267 matches LOOKUP_NAME according to MATCHER to FOUND. */
270 lookup_minimal_symbol_demangled (const lookup_name_info &lookup_name,
272 struct objfile *objfile,
273 struct minimal_symbol **table,
275 symbol_name_matcher_ftype *matcher,
276 found_minimal_symbols &found)
278 for (minimal_symbol *msymbol = table[hash];
280 msymbol = msymbol->demangled_hash_next)
282 const char *symbol_name = MSYMBOL_SEARCH_NAME (msymbol);
284 if (matcher (symbol_name, lookup_name, NULL)
285 && found.maybe_collect (sfile, objfile, msymbol))
290 /* Look through all the current minimal symbol tables and find the
291 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
292 the search to that objfile. If SFILE is non-NULL, the only file-scope
293 symbols considered will be from that source file (global symbols are
294 still preferred). Returns a pointer to the minimal symbol that
295 matches, or NULL if no match is found.
297 Note: One instance where there may be duplicate minimal symbols with
298 the same name is when the symbol tables for a shared library and the
299 symbol tables for an executable contain global symbols with the same
300 names (the dynamic linker deals with the duplication).
302 It's also possible to have minimal symbols with different mangled
303 names, but identical demangled names. For example, the GNU C++ v3
304 ABI requires the generation of two (or perhaps three) copies of
305 constructor functions --- "in-charge", "not-in-charge", and
306 "allocate" copies; destructors may be duplicated as well.
307 Obviously, there must be distinct mangled names for each of these,
308 but the demangled names are all the same: S::S or S::~S. */
310 struct bound_minimal_symbol
311 lookup_minimal_symbol (const char *name, const char *sfile,
312 struct objfile *objf)
314 struct objfile *objfile;
315 found_minimal_symbols found;
317 unsigned int mangled_hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
320 = (case_sensitivity == case_sensitive_on
325 sfile = lbasename (sfile);
327 lookup_name_info lookup_name (name, symbol_name_match_type::FULL);
329 for (objfile = object_files;
330 objfile != NULL && found.external_symbol.minsym == NULL;
331 objfile = objfile->next)
333 struct minimal_symbol *msymbol;
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 = language_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;
455 iterate_over_minimal_symbols (struct objfile *objf,
456 const lookup_name_info &lookup_name,
457 void (*callback) (struct minimal_symbol *,
462 /* The first pass is over the ordinary hash table. */
464 const char *name = lookup_name.name ().c_str ();
465 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
467 = (case_sensitivity == case_sensitive_on
471 for (minimal_symbol *iter = objf->per_bfd->msymbol_hash[hash];
473 iter = iter->hash_next)
475 if (mangled_cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
476 (*callback) (iter, user_data);
480 /* The second pass is over the demangled table. Once for each
481 language in the demangled hash names table (usually just zero or
483 for (auto lang : objf->per_bfd->demangled_hash_languages)
485 const language_defn *lang_def = language_def (lang);
486 symbol_name_matcher_ftype *name_match
487 = language_get_symbol_name_matcher (lang_def, lookup_name);
490 = lookup_name.search_name_hash (lang) % MINIMAL_SYMBOL_HASH_SIZE;
491 for (minimal_symbol *iter = objf->per_bfd->msymbol_demangled_hash[hash];
493 iter = iter->demangled_hash_next)
494 if (name_match (MSYMBOL_SEARCH_NAME (iter), lookup_name, NULL))
495 (*callback) (iter, user_data);
501 struct bound_minimal_symbol
502 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
504 struct objfile *objfile;
505 struct minimal_symbol *msymbol;
506 struct bound_minimal_symbol found_symbol = { NULL, NULL };
507 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
509 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
511 for (objfile = object_files;
512 objfile != NULL && found_symbol.minsym == NULL;
513 objfile = objfile->next)
515 if (objf == NULL || objf == objfile
516 || objf == objfile->separate_debug_objfile_backlink)
518 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
519 msymbol != NULL && found_symbol.minsym == NULL;
520 msymbol = msymbol->hash_next)
522 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
523 (MSYMBOL_TYPE (msymbol) == mst_text
524 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
525 || MSYMBOL_TYPE (msymbol) == mst_file_text))
527 switch (MSYMBOL_TYPE (msymbol))
530 found_file_symbol.minsym = msymbol;
531 found_file_symbol.objfile = objfile;
534 found_symbol.minsym = msymbol;
535 found_symbol.objfile = objfile;
542 /* External symbols are best. */
543 if (found_symbol.minsym)
546 /* File-local symbols are next best. */
547 return found_file_symbol;
552 struct minimal_symbol *
553 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
554 struct objfile *objf)
556 struct objfile *objfile;
557 struct minimal_symbol *msymbol;
559 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
561 for (objfile = object_files;
563 objfile = objfile->next)
565 if (objf == NULL || objf == objfile
566 || objf == objfile->separate_debug_objfile_backlink)
568 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
570 msymbol = msymbol->hash_next)
572 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
573 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
584 struct bound_minimal_symbol
585 lookup_minimal_symbol_solib_trampoline (const char *name,
586 struct objfile *objf)
588 struct objfile *objfile;
589 struct minimal_symbol *msymbol;
590 struct bound_minimal_symbol found_symbol = { NULL, NULL };
592 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
594 for (objfile = object_files;
596 objfile = objfile->next)
598 if (objf == NULL || objf == objfile
599 || objf == objfile->separate_debug_objfile_backlink)
601 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
603 msymbol = msymbol->hash_next)
605 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
606 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
608 found_symbol.objfile = objfile;
609 found_symbol.minsym = msymbol;
619 /* A helper function that makes *PC section-relative. This searches
620 the sections of OBJFILE and if *PC is in a section, it subtracts
621 the section offset and returns true. Otherwise it returns
625 frob_address (struct objfile *objfile, CORE_ADDR *pc)
627 struct obj_section *iter;
629 ALL_OBJFILE_OSECTIONS (objfile, iter)
631 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
633 *pc -= obj_section_offset (iter);
641 /* Search through the minimal symbol table for each objfile and find
642 the symbol whose address is the largest address that is still less
643 than or equal to PC, and matches SECTION (which is not NULL).
644 Returns a pointer to the minimal symbol if such a symbol is found,
645 or NULL if PC is not in a suitable range.
646 Note that we need to look through ALL the minimal symbol tables
647 before deciding on the symbol that comes closest to the specified PC.
648 This is because objfiles can overlap, for example objfile A has .text
649 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
652 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
653 there are text and trampoline symbols at the same address.
654 Otherwise prefer mst_text symbols. */
656 static struct bound_minimal_symbol
657 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc_in,
658 struct obj_section *section,
664 struct objfile *objfile;
665 struct minimal_symbol *msymbol;
666 struct minimal_symbol *best_symbol = NULL;
667 struct objfile *best_objfile = NULL;
668 struct bound_minimal_symbol result;
669 enum minimal_symbol_type want_type, other_type;
671 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
672 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
674 /* We can not require the symbol found to be in section, because
675 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
676 symbol - but find_pc_section won't return an absolute section and
677 hence the code below would skip over absolute symbols. We can
678 still take advantage of the call to find_pc_section, though - the
679 object file still must match. In case we have separate debug
680 files, search both the file and its separate debug file. There's
681 no telling which one will have the minimal symbols. */
683 gdb_assert (section != NULL);
685 for (objfile = section->objfile;
687 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
689 CORE_ADDR pc = pc_in;
691 /* If this objfile has a minimal symbol table, go search it using
692 a binary search. Note that a minimal symbol table always consists
693 of at least two symbols, a "real" symbol and the terminating
694 "null symbol". If there are no real symbols, then there is no
695 minimal symbol table at all. */
697 if (objfile->per_bfd->minimal_symbol_count > 0)
699 int best_zero_sized = -1;
701 msymbol = objfile->per_bfd->msymbols;
703 hi = objfile->per_bfd->minimal_symbol_count - 1;
705 /* This code assumes that the minimal symbols are sorted by
706 ascending address values. If the pc value is greater than or
707 equal to the first symbol's address, then some symbol in this
708 minimal symbol table is a suitable candidate for being the
709 "best" symbol. This includes the last real symbol, for cases
710 where the pc value is larger than any address in this vector.
712 By iterating until the address associated with the current
713 hi index (the endpoint of the test interval) is less than
714 or equal to the desired pc value, we accomplish two things:
715 (1) the case where the pc value is larger than any minimal
716 symbol address is trivially solved, (2) the address associated
717 with the hi index is always the one we want when the interation
718 terminates. In essence, we are iterating the test interval
719 down until the pc value is pushed out of it from the high end.
721 Warning: this code is trickier than it would appear at first. */
723 if (frob_address (objfile, &pc)
724 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
726 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
728 /* pc is still strictly less than highest address. */
729 /* Note "new" will always be >= lo. */
730 newobj = (lo + hi) / 2;
731 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
742 /* If we have multiple symbols at the same address, we want
743 hi to point to the last one. That way we can find the
744 right symbol if it has an index greater than hi. */
745 while (hi < objfile->per_bfd->minimal_symbol_count - 1
746 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
747 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
750 /* Skip various undesirable symbols. */
753 /* Skip any absolute symbols. This is apparently
754 what adb and dbx do, and is needed for the CM-5.
755 There are two known possible problems: (1) on
756 ELF, apparently end, edata, etc. are absolute.
757 Not sure ignoring them here is a big deal, but if
758 we want to use them, the fix would go in
759 elfread.c. (2) I think shared library entry
760 points on the NeXT are absolute. If we want
761 special handling for this it probably should be
762 triggered by a special mst_abs_or_lib or some
765 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
771 /* If SECTION was specified, skip any symbol from
774 /* Some types of debug info, such as COFF,
775 don't fill the bfd_section member, so don't
776 throw away symbols on those platforms. */
777 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
778 && (!matching_obj_sections
779 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
786 /* If we are looking for a trampoline and this is a
787 text symbol, or the other way around, check the
788 preceding symbol too. If they are otherwise
789 identical prefer that one. */
791 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
792 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
793 && (MSYMBOL_SIZE (&msymbol[hi])
794 == MSYMBOL_SIZE (&msymbol[hi - 1]))
795 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
796 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
797 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
798 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
804 /* If the minimal symbol has a zero size, save it
805 but keep scanning backwards looking for one with
806 a non-zero size. A zero size may mean that the
807 symbol isn't an object or function (e.g. a
808 label), or it may just mean that the size was not
810 if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
812 if (best_zero_sized == -1)
813 best_zero_sized = hi;
818 /* If we are past the end of the current symbol, try
819 the previous symbol if it has a larger overlapping
820 size. This happens on i686-pc-linux-gnu with glibc;
821 the nocancel variants of system calls are inside
822 the cancellable variants, but both have sizes. */
824 && MSYMBOL_SIZE (&msymbol[hi]) != 0
825 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
826 + MSYMBOL_SIZE (&msymbol[hi]))
827 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
828 + MSYMBOL_SIZE (&msymbol[hi - 1])))
834 /* Otherwise, this symbol must be as good as we're going
839 /* If HI has a zero size, and best_zero_sized is set,
840 then we had two or more zero-sized symbols; prefer
841 the first one we found (which may have a higher
842 address). Also, if we ran off the end, be sure
844 if (best_zero_sized != -1
845 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
846 hi = best_zero_sized;
848 /* If the minimal symbol has a non-zero size, and this
849 PC appears to be outside the symbol's contents, then
850 refuse to use this symbol. If we found a zero-sized
851 symbol with an address greater than this symbol's,
852 use that instead. We assume that if symbols have
853 specified sizes, they do not overlap. */
856 && MSYMBOL_SIZE (&msymbol[hi]) != 0
857 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
858 + MSYMBOL_SIZE (&msymbol[hi])))
860 if (best_zero_sized != -1)
861 hi = best_zero_sized;
863 /* Go on to the next object file. */
867 /* The minimal symbol indexed by hi now is the best one in this
868 objfile's minimal symbol table. See if it is the best one
872 && ((best_symbol == NULL) ||
873 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
874 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
876 best_symbol = &msymbol[hi];
877 best_objfile = objfile;
883 result.minsym = best_symbol;
884 result.objfile = best_objfile;
888 struct bound_minimal_symbol
889 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
893 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
894 force the section but that (well unless you're doing overlay
895 debugging) always returns NULL making the call somewhat useless. */
896 section = find_pc_section (pc);
899 struct bound_minimal_symbol result;
901 memset (&result, 0, sizeof (result));
905 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
910 struct bound_minimal_symbol
911 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
913 struct obj_section *section = find_pc_section (pc);
917 struct bound_minimal_symbol result;
919 memset (&result, 0, sizeof (result));
922 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
925 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
928 in_gnu_ifunc_stub (CORE_ADDR pc)
930 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
932 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
935 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
938 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
940 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
941 "the ELF support compiled in."),
942 paddress (gdbarch, pc));
945 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
948 stub_gnu_ifunc_resolve_name (const char *function_name,
949 CORE_ADDR *function_address_p)
951 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
952 "the ELF support compiled in."),
956 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
959 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
961 internal_error (__FILE__, __LINE__,
962 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
965 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
968 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
970 internal_error (__FILE__, __LINE__,
971 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
974 /* See elf_gnu_ifunc_fns for its real implementation. */
976 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
978 stub_gnu_ifunc_resolve_addr,
979 stub_gnu_ifunc_resolve_name,
980 stub_gnu_ifunc_resolver_stop,
981 stub_gnu_ifunc_resolver_return_stop,
984 /* A placeholder for &elf_gnu_ifunc_fns. */
986 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
990 struct bound_minimal_symbol
991 lookup_minimal_symbol_and_objfile (const char *name)
993 struct bound_minimal_symbol result;
994 struct objfile *objfile;
995 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
997 ALL_OBJFILES (objfile)
999 struct minimal_symbol *msym;
1001 for (msym = objfile->per_bfd->msymbol_hash[hash];
1003 msym = msym->hash_next)
1005 if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
1007 result.minsym = msym;
1008 result.objfile = objfile;
1014 memset (&result, 0, sizeof (result));
1019 /* Return leading symbol character for a BFD. If BFD is NULL,
1020 return the leading symbol character from the main objfile. */
1023 get_symbol_leading_char (bfd *abfd)
1026 return bfd_get_symbol_leading_char (abfd);
1027 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
1028 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
1032 /* See minsyms.h. */
1034 minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj)
1036 m_msym_bunch (NULL),
1037 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1038 first call to save a minimal symbol to allocate the memory for
1040 m_msym_bunch_index (BUNCH_SIZE),
1045 /* Discard the currently collected minimal symbols, if any. If we wish
1046 to save them for later use, we must have already copied them somewhere
1047 else before calling this function.
1049 FIXME: We could allocate the minimal symbol bunches on their own
1050 obstack and then simply blow the obstack away when we are done with
1051 it. Is it worth the extra trouble though? */
1053 minimal_symbol_reader::~minimal_symbol_reader ()
1055 struct msym_bunch *next;
1057 while (m_msym_bunch != NULL)
1059 next = m_msym_bunch->next;
1060 xfree (m_msym_bunch);
1061 m_msym_bunch = next;
1065 /* See minsyms.h. */
1068 minimal_symbol_reader::record (const char *name, CORE_ADDR address,
1069 enum minimal_symbol_type ms_type)
1076 case mst_text_gnu_ifunc:
1078 case mst_solib_trampoline:
1079 section = SECT_OFF_TEXT (m_objfile);
1083 section = SECT_OFF_DATA (m_objfile);
1087 section = SECT_OFF_BSS (m_objfile);
1093 record_with_info (name, address, ms_type, section);
1096 /* See minsyms.h. */
1098 struct minimal_symbol *
1099 minimal_symbol_reader::record_full (const char *name, int name_len,
1100 bool copy_name, CORE_ADDR address,
1101 enum minimal_symbol_type ms_type,
1104 struct msym_bunch *newobj;
1105 struct minimal_symbol *msymbol;
1107 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1108 the minimal symbols, because if there is also another symbol
1109 at the same address (e.g. the first function of the file),
1110 lookup_minimal_symbol_by_pc would have no way of getting the
1112 if (ms_type == mst_file_text && name[0] == 'g'
1113 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
1114 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
1117 /* It's safe to strip the leading char here once, since the name
1118 is also stored stripped in the minimal symbol table. */
1119 if (name[0] == get_symbol_leading_char (m_objfile->obfd))
1125 if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
1128 if (m_msym_bunch_index == BUNCH_SIZE)
1130 newobj = XCNEW (struct msym_bunch);
1131 m_msym_bunch_index = 0;
1132 newobj->next = m_msym_bunch;
1133 m_msym_bunch = newobj;
1135 msymbol = &m_msym_bunch->contents[m_msym_bunch_index];
1136 MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
1137 &m_objfile->per_bfd->storage_obstack);
1138 MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, m_objfile);
1140 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1141 MSYMBOL_SECTION (msymbol) = section;
1143 MSYMBOL_TYPE (msymbol) = ms_type;
1144 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
1145 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
1146 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
1147 as it would also set the has_size flag. */
1150 /* The hash pointers must be cleared! If they're not,
1151 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
1152 msymbol->hash_next = NULL;
1153 msymbol->demangled_hash_next = NULL;
1155 /* If we already read minimal symbols for this objfile, then don't
1156 ever allocate a new one. */
1157 if (!m_objfile->per_bfd->minsyms_read)
1159 m_msym_bunch_index++;
1160 m_objfile->per_bfd->n_minsyms++;
1166 /* Compare two minimal symbols by address and return a signed result based
1167 on unsigned comparisons, so that we sort into unsigned numeric order.
1168 Within groups with the same address, sort by name. */
1171 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1173 const struct minimal_symbol *fn1;
1174 const struct minimal_symbol *fn2;
1176 fn1 = (const struct minimal_symbol *) fn1p;
1177 fn2 = (const struct minimal_symbol *) fn2p;
1179 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1181 return (-1); /* addr 1 is less than addr 2. */
1183 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1185 return (1); /* addr 1 is greater than addr 2. */
1188 /* addrs are equal: sort by name */
1190 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1191 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1193 if (name1 && name2) /* both have names */
1194 return strcmp (name1, name2);
1196 return 1; /* fn1 has no name, so it is "less". */
1197 else if (name1) /* fn2 has no name, so it is "less". */
1200 return (0); /* Neither has a name, so they're equal. */
1204 /* Compact duplicate entries out of a minimal symbol table by walking
1205 through the table and compacting out entries with duplicate addresses
1206 and matching names. Return the number of entries remaining.
1208 On entry, the table resides between msymbol[0] and msymbol[mcount].
1209 On exit, it resides between msymbol[0] and msymbol[result_count].
1211 When files contain multiple sources of symbol information, it is
1212 possible for the minimal symbol table to contain many duplicate entries.
1213 As an example, SVR4 systems use ELF formatted object files, which
1214 usually contain at least two different types of symbol tables (a
1215 standard ELF one and a smaller dynamic linking table), as well as
1216 DWARF debugging information for files compiled with -g.
1218 Without compacting, the minimal symbol table for gdb itself contains
1219 over a 1000 duplicates, about a third of the total table size. Aside
1220 from the potential trap of not noticing that two successive entries
1221 identify the same location, this duplication impacts the time required
1222 to linearly scan the table, which is done in a number of places. So we
1223 just do one linear scan here and toss out the duplicates.
1225 Note that we are not concerned here about recovering the space that
1226 is potentially freed up, because the strings themselves are allocated
1227 on the storage_obstack, and will get automatically freed when the symbol
1228 table is freed. The caller can free up the unused minimal symbols at
1229 the end of the compacted region if their allocation strategy allows it.
1231 Also note we only go up to the next to last entry within the loop
1232 and then copy the last entry explicitly after the loop terminates.
1234 Since the different sources of information for each symbol may
1235 have different levels of "completeness", we may have duplicates
1236 that have one entry with type "mst_unknown" and the other with a
1237 known type. So if the one we are leaving alone has type mst_unknown,
1238 overwrite its type with the type from the one we are compacting out. */
1241 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1242 struct objfile *objfile)
1244 struct minimal_symbol *copyfrom;
1245 struct minimal_symbol *copyto;
1249 copyfrom = copyto = msymbol;
1250 while (copyfrom < msymbol + mcount - 1)
1252 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1253 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1254 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1255 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1256 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1258 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1260 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1265 *copyto++ = *copyfrom++;
1267 *copyto++ = *copyfrom++;
1268 mcount = copyto - msymbol;
1273 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1274 after compacting or sorting the table since the entries move around
1275 thus causing the internal minimal_symbol pointers to become jumbled. */
1278 build_minimal_symbol_hash_tables (struct objfile *objfile)
1281 struct minimal_symbol *msym;
1283 /* Clear the hash tables. */
1284 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1286 objfile->per_bfd->msymbol_hash[i] = 0;
1287 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1290 /* Now, (re)insert the actual entries. */
1291 for ((i = objfile->per_bfd->minimal_symbol_count,
1292 msym = objfile->per_bfd->msymbols);
1296 msym->hash_next = 0;
1297 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1299 msym->demangled_hash_next = 0;
1300 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1301 add_minsym_to_demangled_hash_table (msym, objfile);
1305 /* Add the minimal symbols in the existing bunches to the objfile's official
1306 minimal symbol table. In most cases there is no minimal symbol table yet
1307 for this objfile, and the existing bunches are used to create one. Once
1308 in a while (for shared libraries for example), we add symbols (e.g. common
1309 symbols) to an existing objfile.
1311 Because of the way minimal symbols are collected, we generally have no way
1312 of knowing what source language applies to any particular minimal symbol.
1313 Specifically, we have no way of knowing if the minimal symbol comes from a
1314 C++ compilation unit or not. So for the sake of supporting cached
1315 demangled C++ names, we have no choice but to try and demangle each new one
1316 that comes in. If the demangling succeeds, then we assume it is a C++
1317 symbol and set the symbol's language and demangled name fields
1318 appropriately. Note that in order to avoid unnecessary demanglings, and
1319 allocating obstack space that subsequently can't be freed for the demangled
1320 names, we mark all newly added symbols with language_auto. After
1321 compaction of the minimal symbols, we go back and scan the entire minimal
1322 symbol table looking for these new symbols. For each new symbol we attempt
1323 to demangle it, and if successful, record it as a language_cplus symbol
1324 and cache the demangled form on the symbol obstack. Symbols which don't
1325 demangle are marked as language_unknown symbols, which inhibits future
1326 attempts to demangle them if we later add more minimal symbols. */
1329 minimal_symbol_reader::install ()
1333 struct msym_bunch *bunch;
1334 struct minimal_symbol *msymbols;
1337 if (m_objfile->per_bfd->minsyms_read)
1340 if (m_msym_count > 0)
1342 if (symtab_create_debug)
1344 fprintf_unfiltered (gdb_stdlog,
1345 "Installing %d minimal symbols of objfile %s.\n",
1346 m_msym_count, objfile_name (m_objfile));
1349 /* Allocate enough space in the obstack, into which we will gather the
1350 bunches of new and existing minimal symbols, sort them, and then
1351 compact out the duplicate entries. Once we have a final table,
1352 we will give back the excess space. */
1354 alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count + 1;
1355 obstack_blank (&m_objfile->per_bfd->storage_obstack,
1356 alloc_count * sizeof (struct minimal_symbol));
1357 msymbols = (struct minimal_symbol *)
1358 obstack_base (&m_objfile->per_bfd->storage_obstack);
1360 /* Copy in the existing minimal symbols, if there are any. */
1362 if (m_objfile->per_bfd->minimal_symbol_count)
1363 memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols,
1364 m_objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol));
1366 /* Walk through the list of minimal symbol bunches, adding each symbol
1367 to the new contiguous array of symbols. Note that we start with the
1368 current, possibly partially filled bunch (thus we use the current
1369 msym_bunch_index for the first bunch we copy over), and thereafter
1370 each bunch is full. */
1372 mcount = m_objfile->per_bfd->minimal_symbol_count;
1374 for (bunch = m_msym_bunch; bunch != NULL; bunch = bunch->next)
1376 for (bindex = 0; bindex < m_msym_bunch_index; bindex++, mcount++)
1377 msymbols[mcount] = bunch->contents[bindex];
1378 m_msym_bunch_index = BUNCH_SIZE;
1381 /* Sort the minimal symbols by address. */
1383 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1384 compare_minimal_symbols);
1386 /* Compact out any duplicates, and free up whatever space we are
1389 mcount = compact_minimal_symbols (msymbols, mcount, m_objfile);
1391 obstack_blank_fast (&m_objfile->per_bfd->storage_obstack,
1392 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1393 msymbols = (struct minimal_symbol *)
1394 obstack_finish (&m_objfile->per_bfd->storage_obstack);
1396 /* We also terminate the minimal symbol table with a "null symbol",
1397 which is *not* included in the size of the table. This makes it
1398 easier to find the end of the table when we are handed a pointer
1399 to some symbol in the middle of it. Zero out the fields in the
1400 "null symbol" allocated at the end of the array. Note that the
1401 symbol count does *not* include this null symbol, which is why it
1402 is indexed by mcount and not mcount-1. */
1404 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1406 /* Attach the minimal symbol table to the specified objfile.
1407 The strings themselves are also located in the storage_obstack
1410 m_objfile->per_bfd->minimal_symbol_count = mcount;
1411 m_objfile->per_bfd->msymbols = msymbols;
1413 /* Now build the hash tables; we can't do this incrementally
1414 at an earlier point since we weren't finished with the obstack
1415 yet. (And if the msymbol obstack gets moved, all the internal
1416 pointers to other msymbols need to be adjusted.) */
1417 build_minimal_symbol_hash_tables (m_objfile);
1421 /* See minsyms.h. */
1424 terminate_minimal_symbol_table (struct objfile *objfile)
1426 if (! objfile->per_bfd->msymbols)
1427 objfile->per_bfd->msymbols
1428 = ((struct minimal_symbol *)
1429 obstack_alloc (&objfile->per_bfd->storage_obstack,
1430 sizeof (struct minimal_symbol)));
1433 struct minimal_symbol *m
1434 = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1436 memset (m, 0, sizeof (*m));
1437 /* Don't rely on these enumeration values being 0's. */
1438 MSYMBOL_TYPE (m) = mst_unknown;
1439 MSYMBOL_SET_LANGUAGE (m, language_unknown,
1440 &objfile->per_bfd->storage_obstack);
1444 /* Check if PC is in a shared library trampoline code stub.
1445 Return minimal symbol for the trampoline entry or NULL if PC is not
1446 in a trampoline code stub. */
1448 static struct minimal_symbol *
1449 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1451 struct obj_section *section = find_pc_section (pc);
1452 struct bound_minimal_symbol msymbol;
1454 if (section == NULL)
1456 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1458 if (msymbol.minsym != NULL
1459 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1460 return msymbol.minsym;
1464 /* If PC is in a shared library trampoline code stub, return the
1465 address of the `real' function belonging to the stub.
1466 Return 0 if PC is not in a trampoline code stub or if the real
1467 function is not found in the minimal symbol table.
1469 We may fail to find the right function if a function with the
1470 same name is defined in more than one shared library, but this
1471 is considered bad programming style. We could return 0 if we find
1472 a duplicate function in case this matters someday. */
1475 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1477 struct objfile *objfile;
1478 struct minimal_symbol *msymbol;
1479 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1481 if (tsymbol != NULL)
1483 ALL_MSYMBOLS (objfile, msymbol)
1485 if ((MSYMBOL_TYPE (msymbol) == mst_text
1486 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1487 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1488 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1489 return MSYMBOL_VALUE_ADDRESS (objfile, msymbol);
1491 /* Also handle minimal symbols pointing to function descriptors. */
1492 if (MSYMBOL_TYPE (msymbol) == mst_data
1493 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1494 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1498 func = gdbarch_convert_from_func_ptr_addr
1499 (get_objfile_arch (objfile),
1500 MSYMBOL_VALUE_ADDRESS (objfile, msymbol),
1503 /* Ignore data symbols that are not function descriptors. */
1504 if (func != MSYMBOL_VALUE_ADDRESS (objfile, msymbol))
1512 /* See minsyms.h. */
1515 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1519 struct obj_section *obj_section;
1521 struct minimal_symbol *msymbol;
1523 gdb_assert (minsym.minsym != NULL);
1525 /* If the minimal symbol has a size, use it. Otherwise use the
1526 lesser of the next minimal symbol in the same section, or the end
1527 of the section, as the end of the function. */
1529 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1530 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1532 /* Step over other symbols at this same address, and symbols in
1533 other sections, to find the next symbol in this section with a
1534 different address. */
1536 msymbol = minsym.minsym;
1537 section = MSYMBOL_SECTION (msymbol);
1538 for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1540 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1541 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1542 && MSYMBOL_SECTION (msymbol + i) == section)
1546 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1547 if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1548 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1549 < obj_section_endaddr (obj_section)))
1550 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
1552 /* We got the start address from the last msymbol in the objfile.
1553 So the end address is the end of the section. */
1554 result = obj_section_endaddr (obj_section);