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"
58 msymbol_is_text (minimal_symbol *msymbol)
60 switch (MSYMBOL_TYPE (msymbol))
63 case mst_text_gnu_ifunc:
64 case mst_solib_trampoline:
72 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
73 At the end, copy them all into one newly allocated location on an objfile's
74 per-BFD storage obstack. */
76 #define BUNCH_SIZE 127
80 struct msym_bunch *next;
81 struct minimal_symbol contents[BUNCH_SIZE];
87 msymbol_hash_iw (const char *string)
89 unsigned int hash = 0;
91 while (*string && *string != '(')
93 string = skip_spaces_const (string);
94 if (*string && *string != '(')
96 hash = SYMBOL_HASH_NEXT (hash, *string);
106 msymbol_hash (const char *string)
108 unsigned int hash = 0;
110 for (; *string; ++string)
111 hash = SYMBOL_HASH_NEXT (hash, *string);
115 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
117 add_minsym_to_hash_table (struct minimal_symbol *sym,
118 struct minimal_symbol **table)
120 if (sym->hash_next == NULL)
123 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
125 sym->hash_next = table[hash];
130 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
133 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
134 struct minimal_symbol **table)
136 if (sym->demangled_hash_next == NULL)
138 unsigned int hash = msymbol_hash_iw (MSYMBOL_SEARCH_NAME (sym))
139 % MINIMAL_SYMBOL_HASH_SIZE;
141 sym->demangled_hash_next = table[hash];
146 /* Look through all the current minimal symbol tables and find the
147 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
148 the search to that objfile. If SFILE is non-NULL, the only file-scope
149 symbols considered will be from that source file (global symbols are
150 still preferred). Returns a pointer to the minimal symbol that
151 matches, or NULL if no match is found.
153 Note: One instance where there may be duplicate minimal symbols with
154 the same name is when the symbol tables for a shared library and the
155 symbol tables for an executable contain global symbols with the same
156 names (the dynamic linker deals with the duplication).
158 It's also possible to have minimal symbols with different mangled
159 names, but identical demangled names. For example, the GNU C++ v3
160 ABI requires the generation of two (or perhaps three) copies of
161 constructor functions --- "in-charge", "not-in-charge", and
162 "allocate" copies; destructors may be duplicated as well.
163 Obviously, there must be distinct mangled names for each of these,
164 but the demangled names are all the same: S::S or S::~S. */
166 struct bound_minimal_symbol
167 lookup_minimal_symbol (const char *name, const char *sfile,
168 struct objfile *objf)
170 struct objfile *objfile;
171 struct bound_minimal_symbol found_symbol = { NULL, NULL };
172 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
173 struct bound_minimal_symbol trampoline_symbol = { NULL, NULL };
175 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
176 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
178 const char *modified_name = name;
181 sfile = lbasename (sfile);
183 /* For C++, canonicalize the input name. */
184 std::string modified_name_storage;
185 if (current_language->la_language == language_cplus)
187 std::string cname = cp_canonicalize_string (name);
190 std::swap (modified_name_storage, cname);
191 modified_name = modified_name_storage.c_str ();
195 for (objfile = object_files;
196 objfile != NULL && found_symbol.minsym == NULL;
197 objfile = objfile->next)
199 struct minimal_symbol *msymbol;
201 if (objf == NULL || objf == objfile
202 || objf == objfile->separate_debug_objfile_backlink)
204 /* Do two passes: the first over the ordinary hash table,
205 and the second over the demangled hash table. */
208 if (symbol_lookup_debug)
210 fprintf_unfiltered (gdb_stdlog,
211 "lookup_minimal_symbol (%s, %s, %s)\n",
212 name, sfile != NULL ? sfile : "NULL",
213 objfile_debug_name (objfile));
216 for (pass = 1; pass <= 2 && found_symbol.minsym == NULL; pass++)
218 /* Select hash list according to pass. */
220 msymbol = objfile->per_bfd->msymbol_hash[hash];
222 msymbol = objfile->per_bfd->msymbol_demangled_hash[dem_hash];
224 while (msymbol != NULL && found_symbol.minsym == NULL)
230 int (*cmp) (const char *, const char *);
232 cmp = (case_sensitivity == case_sensitive_on
233 ? strcmp : strcasecmp);
234 match = cmp (MSYMBOL_LINKAGE_NAME (msymbol),
239 /* The function respects CASE_SENSITIVITY. */
240 match = MSYMBOL_MATCHES_SEARCH_NAME (msymbol,
246 switch (MSYMBOL_TYPE (msymbol))
252 || filename_cmp (msymbol->filename, sfile) == 0)
254 found_file_symbol.minsym = msymbol;
255 found_file_symbol.objfile = objfile;
259 case mst_solib_trampoline:
261 /* If a trampoline symbol is found, we prefer to
262 keep looking for the *real* symbol. If the
263 actual symbol is not found, then we'll use the
265 if (trampoline_symbol.minsym == NULL)
267 trampoline_symbol.minsym = msymbol;
268 trampoline_symbol.objfile = objfile;
274 found_symbol.minsym = msymbol;
275 found_symbol.objfile = objfile;
280 /* Find the next symbol on the hash chain. */
282 msymbol = msymbol->hash_next;
284 msymbol = msymbol->demangled_hash_next;
290 /* External symbols are best. */
291 if (found_symbol.minsym != NULL)
293 if (symbol_lookup_debug)
295 fprintf_unfiltered (gdb_stdlog,
296 "lookup_minimal_symbol (...) = %s"
298 host_address_to_string (found_symbol.minsym));
303 /* File-local symbols are next best. */
304 if (found_file_symbol.minsym != NULL)
306 if (symbol_lookup_debug)
308 fprintf_unfiltered (gdb_stdlog,
309 "lookup_minimal_symbol (...) = %s"
311 host_address_to_string
312 (found_file_symbol.minsym));
314 return found_file_symbol;
317 /* Symbols for shared library trampolines are next best. */
318 if (symbol_lookup_debug)
320 fprintf_unfiltered (gdb_stdlog,
321 "lookup_minimal_symbol (...) = %s%s\n",
322 trampoline_symbol.minsym != NULL
323 ? host_address_to_string (trampoline_symbol.minsym)
325 trampoline_symbol.minsym != NULL
326 ? " (trampoline)" : "");
328 return trampoline_symbol;
333 struct bound_minimal_symbol
334 lookup_bound_minimal_symbol (const char *name)
336 return lookup_minimal_symbol (name, NULL, NULL);
339 /* See common/symbol.h. */
342 find_minimal_symbol_address (const char *name, CORE_ADDR *addr,
343 struct objfile *objfile)
345 struct bound_minimal_symbol sym
346 = lookup_minimal_symbol (name, NULL, objfile);
348 if (sym.minsym != NULL)
349 *addr = BMSYMBOL_VALUE_ADDRESS (sym);
351 return sym.minsym == NULL;
357 iterate_over_minimal_symbols (struct objfile *objf, const char *name,
358 void (*callback) (struct minimal_symbol *,
363 struct minimal_symbol *iter;
364 int (*cmp) (const char *, const char *);
366 /* The first pass is over the ordinary hash table. */
367 hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
368 iter = objf->per_bfd->msymbol_hash[hash];
369 cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);
372 if (cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
373 (*callback) (iter, user_data);
374 iter = iter->hash_next;
377 /* The second pass is over the demangled table. */
378 hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
379 iter = objf->per_bfd->msymbol_demangled_hash[hash];
382 if (MSYMBOL_MATCHES_SEARCH_NAME (iter, name))
383 (*callback) (iter, user_data);
384 iter = iter->demangled_hash_next;
390 struct bound_minimal_symbol
391 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
393 struct objfile *objfile;
394 struct minimal_symbol *msymbol;
395 struct bound_minimal_symbol found_symbol = { NULL, NULL };
396 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
398 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
400 for (objfile = object_files;
401 objfile != NULL && found_symbol.minsym == NULL;
402 objfile = objfile->next)
404 if (objf == NULL || objf == objfile
405 || objf == objfile->separate_debug_objfile_backlink)
407 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
408 msymbol != NULL && found_symbol.minsym == NULL;
409 msymbol = msymbol->hash_next)
411 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
412 (MSYMBOL_TYPE (msymbol) == mst_text
413 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
414 || MSYMBOL_TYPE (msymbol) == mst_file_text))
416 switch (MSYMBOL_TYPE (msymbol))
419 found_file_symbol.minsym = msymbol;
420 found_file_symbol.objfile = objfile;
423 found_symbol.minsym = msymbol;
424 found_symbol.objfile = objfile;
431 /* External symbols are best. */
432 if (found_symbol.minsym)
435 /* File-local symbols are next best. */
436 return found_file_symbol;
441 struct minimal_symbol *
442 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
443 struct objfile *objf)
445 struct objfile *objfile;
446 struct minimal_symbol *msymbol;
448 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
450 for (objfile = object_files;
452 objfile = objfile->next)
454 if (objf == NULL || objf == objfile
455 || objf == objfile->separate_debug_objfile_backlink)
457 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
459 msymbol = msymbol->hash_next)
461 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
462 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
473 struct bound_minimal_symbol
474 lookup_minimal_symbol_solib_trampoline (const char *name,
475 struct objfile *objf)
477 struct objfile *objfile;
478 struct minimal_symbol *msymbol;
479 struct bound_minimal_symbol found_symbol = { NULL, NULL };
481 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
483 for (objfile = object_files;
485 objfile = objfile->next)
487 if (objf == NULL || objf == objfile
488 || objf == objfile->separate_debug_objfile_backlink)
490 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
492 msymbol = msymbol->hash_next)
494 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
495 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
497 found_symbol.objfile = objfile;
498 found_symbol.minsym = msymbol;
508 /* A helper function that makes *PC section-relative. This searches
509 the sections of OBJFILE and if *PC is in a section, it subtracts
510 the section offset and returns true. Otherwise it returns
514 frob_address (struct objfile *objfile, CORE_ADDR *pc)
516 struct obj_section *iter;
518 ALL_OBJFILE_OSECTIONS (objfile, iter)
520 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
522 *pc -= obj_section_offset (iter);
530 /* Search through the minimal symbol table for each objfile and find
531 the symbol whose address is the largest address that is still less
532 than or equal to PC, and matches SECTION (which is not NULL).
533 Returns a pointer to the minimal symbol if such a symbol is found,
534 or NULL if PC is not in a suitable range.
535 Note that we need to look through ALL the minimal symbol tables
536 before deciding on the symbol that comes closest to the specified PC.
537 This is because objfiles can overlap, for example objfile A has .text
538 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
541 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
542 there are text and trampoline symbols at the same address.
543 Otherwise prefer mst_text symbols. */
545 static struct bound_minimal_symbol
546 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc_in,
547 struct obj_section *section,
553 struct objfile *objfile;
554 struct minimal_symbol *msymbol;
555 struct minimal_symbol *best_symbol = NULL;
556 struct objfile *best_objfile = NULL;
557 struct bound_minimal_symbol result;
558 enum minimal_symbol_type want_type, other_type;
560 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
561 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
563 /* We can not require the symbol found to be in section, because
564 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
565 symbol - but find_pc_section won't return an absolute section and
566 hence the code below would skip over absolute symbols. We can
567 still take advantage of the call to find_pc_section, though - the
568 object file still must match. In case we have separate debug
569 files, search both the file and its separate debug file. There's
570 no telling which one will have the minimal symbols. */
572 gdb_assert (section != NULL);
574 for (objfile = section->objfile;
576 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
578 CORE_ADDR pc = pc_in;
580 /* If this objfile has a minimal symbol table, go search it using
581 a binary search. Note that a minimal symbol table always consists
582 of at least two symbols, a "real" symbol and the terminating
583 "null symbol". If there are no real symbols, then there is no
584 minimal symbol table at all. */
586 if (objfile->per_bfd->minimal_symbol_count > 0)
588 int best_zero_sized = -1;
590 msymbol = objfile->per_bfd->msymbols;
592 hi = objfile->per_bfd->minimal_symbol_count - 1;
594 /* This code assumes that the minimal symbols are sorted by
595 ascending address values. If the pc value is greater than or
596 equal to the first symbol's address, then some symbol in this
597 minimal symbol table is a suitable candidate for being the
598 "best" symbol. This includes the last real symbol, for cases
599 where the pc value is larger than any address in this vector.
601 By iterating until the address associated with the current
602 hi index (the endpoint of the test interval) is less than
603 or equal to the desired pc value, we accomplish two things:
604 (1) the case where the pc value is larger than any minimal
605 symbol address is trivially solved, (2) the address associated
606 with the hi index is always the one we want when the interation
607 terminates. In essence, we are iterating the test interval
608 down until the pc value is pushed out of it from the high end.
610 Warning: this code is trickier than it would appear at first. */
612 if (frob_address (objfile, &pc)
613 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
615 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
617 /* pc is still strictly less than highest address. */
618 /* Note "new" will always be >= lo. */
619 newobj = (lo + hi) / 2;
620 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
631 /* If we have multiple symbols at the same address, we want
632 hi to point to the last one. That way we can find the
633 right symbol if it has an index greater than hi. */
634 while (hi < objfile->per_bfd->minimal_symbol_count - 1
635 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
636 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
639 /* Skip various undesirable symbols. */
642 /* Skip any absolute symbols. This is apparently
643 what adb and dbx do, and is needed for the CM-5.
644 There are two known possible problems: (1) on
645 ELF, apparently end, edata, etc. are absolute.
646 Not sure ignoring them here is a big deal, but if
647 we want to use them, the fix would go in
648 elfread.c. (2) I think shared library entry
649 points on the NeXT are absolute. If we want
650 special handling for this it probably should be
651 triggered by a special mst_abs_or_lib or some
654 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
660 /* If SECTION was specified, skip any symbol from
663 /* Some types of debug info, such as COFF,
664 don't fill the bfd_section member, so don't
665 throw away symbols on those platforms. */
666 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
667 && (!matching_obj_sections
668 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
675 /* If we are looking for a trampoline and this is a
676 text symbol, or the other way around, check the
677 preceding symbol too. If they are otherwise
678 identical prefer that one. */
680 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
681 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
682 && (MSYMBOL_SIZE (&msymbol[hi])
683 == MSYMBOL_SIZE (&msymbol[hi - 1]))
684 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
685 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
686 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
687 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
693 /* If the minimal symbol has a zero size, save it
694 but keep scanning backwards looking for one with
695 a non-zero size. A zero size may mean that the
696 symbol isn't an object or function (e.g. a
697 label), or it may just mean that the size was not
699 if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
701 if (best_zero_sized == -1)
702 best_zero_sized = hi;
707 /* If we are past the end of the current symbol, try
708 the previous symbol if it has a larger overlapping
709 size. This happens on i686-pc-linux-gnu with glibc;
710 the nocancel variants of system calls are inside
711 the cancellable variants, but both have sizes. */
713 && MSYMBOL_SIZE (&msymbol[hi]) != 0
714 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
715 + MSYMBOL_SIZE (&msymbol[hi]))
716 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
717 + MSYMBOL_SIZE (&msymbol[hi - 1])))
723 /* Otherwise, this symbol must be as good as we're going
728 /* If HI has a zero size, and best_zero_sized is set,
729 then we had two or more zero-sized symbols; prefer
730 the first one we found (which may have a higher
731 address). Also, if we ran off the end, be sure
733 if (best_zero_sized != -1
734 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
735 hi = best_zero_sized;
737 /* If the minimal symbol has a non-zero size, and this
738 PC appears to be outside the symbol's contents, then
739 refuse to use this symbol. If we found a zero-sized
740 symbol with an address greater than this symbol's,
741 use that instead. We assume that if symbols have
742 specified sizes, they do not overlap. */
745 && MSYMBOL_SIZE (&msymbol[hi]) != 0
746 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
747 + MSYMBOL_SIZE (&msymbol[hi])))
749 if (best_zero_sized != -1)
750 hi = best_zero_sized;
752 /* Go on to the next object file. */
756 /* The minimal symbol indexed by hi now is the best one in this
757 objfile's minimal symbol table. See if it is the best one
761 && ((best_symbol == NULL) ||
762 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
763 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
765 best_symbol = &msymbol[hi];
766 best_objfile = objfile;
772 result.minsym = best_symbol;
773 result.objfile = best_objfile;
777 struct bound_minimal_symbol
778 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
782 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
783 force the section but that (well unless you're doing overlay
784 debugging) always returns NULL making the call somewhat useless. */
785 section = find_pc_section (pc);
788 struct bound_minimal_symbol result;
790 memset (&result, 0, sizeof (result));
794 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
799 struct bound_minimal_symbol
800 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
802 struct obj_section *section = find_pc_section (pc);
806 struct bound_minimal_symbol result;
808 memset (&result, 0, sizeof (result));
811 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
814 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
817 in_gnu_ifunc_stub (CORE_ADDR pc)
819 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
821 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
824 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
827 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
829 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
830 "the ELF support compiled in."),
831 paddress (gdbarch, pc));
834 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
837 stub_gnu_ifunc_resolve_name (const char *function_name,
838 CORE_ADDR *function_address_p)
840 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
841 "the ELF support compiled in."),
845 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
848 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
850 internal_error (__FILE__, __LINE__,
851 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
854 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
857 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
859 internal_error (__FILE__, __LINE__,
860 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
863 /* See elf_gnu_ifunc_fns for its real implementation. */
865 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
867 stub_gnu_ifunc_resolve_addr,
868 stub_gnu_ifunc_resolve_name,
869 stub_gnu_ifunc_resolver_stop,
870 stub_gnu_ifunc_resolver_return_stop,
873 /* A placeholder for &elf_gnu_ifunc_fns. */
875 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
879 struct bound_minimal_symbol
880 lookup_minimal_symbol_and_objfile (const char *name)
882 struct bound_minimal_symbol result;
883 struct objfile *objfile;
884 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
886 ALL_OBJFILES (objfile)
888 struct minimal_symbol *msym;
890 for (msym = objfile->per_bfd->msymbol_hash[hash];
892 msym = msym->hash_next)
894 if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
896 result.minsym = msym;
897 result.objfile = objfile;
903 memset (&result, 0, sizeof (result));
908 /* Return leading symbol character for a BFD. If BFD is NULL,
909 return the leading symbol character from the main objfile. */
912 get_symbol_leading_char (bfd *abfd)
915 return bfd_get_symbol_leading_char (abfd);
916 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
917 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
923 minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj)
926 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
927 first call to save a minimal symbol to allocate the memory for
929 m_msym_bunch_index (BUNCH_SIZE),
934 /* Discard the currently collected minimal symbols, if any. If we wish
935 to save them for later use, we must have already copied them somewhere
936 else before calling this function.
938 FIXME: We could allocate the minimal symbol bunches on their own
939 obstack and then simply blow the obstack away when we are done with
940 it. Is it worth the extra trouble though? */
942 minimal_symbol_reader::~minimal_symbol_reader ()
944 struct msym_bunch *next;
946 while (m_msym_bunch != NULL)
948 next = m_msym_bunch->next;
949 xfree (m_msym_bunch);
957 minimal_symbol_reader::record (const char *name, CORE_ADDR address,
958 enum minimal_symbol_type ms_type)
965 case mst_text_gnu_ifunc:
967 case mst_solib_trampoline:
968 section = SECT_OFF_TEXT (m_objfile);
972 section = SECT_OFF_DATA (m_objfile);
976 section = SECT_OFF_BSS (m_objfile);
982 record_with_info (name, address, ms_type, section);
987 struct minimal_symbol *
988 minimal_symbol_reader::record_full (const char *name, int name_len,
989 bool copy_name, CORE_ADDR address,
990 enum minimal_symbol_type ms_type,
993 struct msym_bunch *newobj;
994 struct minimal_symbol *msymbol;
996 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
997 the minimal symbols, because if there is also another symbol
998 at the same address (e.g. the first function of the file),
999 lookup_minimal_symbol_by_pc would have no way of getting the
1001 if (ms_type == mst_file_text && name[0] == 'g'
1002 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
1003 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
1006 /* It's safe to strip the leading char here once, since the name
1007 is also stored stripped in the minimal symbol table. */
1008 if (name[0] == get_symbol_leading_char (m_objfile->obfd))
1014 if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
1017 if (m_msym_bunch_index == BUNCH_SIZE)
1019 newobj = XCNEW (struct msym_bunch);
1020 m_msym_bunch_index = 0;
1021 newobj->next = m_msym_bunch;
1022 m_msym_bunch = newobj;
1024 msymbol = &m_msym_bunch->contents[m_msym_bunch_index];
1025 MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
1026 &m_objfile->per_bfd->storage_obstack);
1027 MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, m_objfile);
1029 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1030 MSYMBOL_SECTION (msymbol) = section;
1032 MSYMBOL_TYPE (msymbol) = ms_type;
1033 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
1034 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
1035 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
1036 as it would also set the has_size flag. */
1039 /* The hash pointers must be cleared! If they're not,
1040 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
1041 msymbol->hash_next = NULL;
1042 msymbol->demangled_hash_next = NULL;
1044 /* If we already read minimal symbols for this objfile, then don't
1045 ever allocate a new one. */
1046 if (!m_objfile->per_bfd->minsyms_read)
1048 m_msym_bunch_index++;
1049 m_objfile->per_bfd->n_minsyms++;
1055 /* Compare two minimal symbols by address and return a signed result based
1056 on unsigned comparisons, so that we sort into unsigned numeric order.
1057 Within groups with the same address, sort by name. */
1060 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1062 const struct minimal_symbol *fn1;
1063 const struct minimal_symbol *fn2;
1065 fn1 = (const struct minimal_symbol *) fn1p;
1066 fn2 = (const struct minimal_symbol *) fn2p;
1068 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1070 return (-1); /* addr 1 is less than addr 2. */
1072 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1074 return (1); /* addr 1 is greater than addr 2. */
1077 /* addrs are equal: sort by name */
1079 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1080 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1082 if (name1 && name2) /* both have names */
1083 return strcmp (name1, name2);
1085 return 1; /* fn1 has no name, so it is "less". */
1086 else if (name1) /* fn2 has no name, so it is "less". */
1089 return (0); /* Neither has a name, so they're equal. */
1093 /* Compact duplicate entries out of a minimal symbol table by walking
1094 through the table and compacting out entries with duplicate addresses
1095 and matching names. Return the number of entries remaining.
1097 On entry, the table resides between msymbol[0] and msymbol[mcount].
1098 On exit, it resides between msymbol[0] and msymbol[result_count].
1100 When files contain multiple sources of symbol information, it is
1101 possible for the minimal symbol table to contain many duplicate entries.
1102 As an example, SVR4 systems use ELF formatted object files, which
1103 usually contain at least two different types of symbol tables (a
1104 standard ELF one and a smaller dynamic linking table), as well as
1105 DWARF debugging information for files compiled with -g.
1107 Without compacting, the minimal symbol table for gdb itself contains
1108 over a 1000 duplicates, about a third of the total table size. Aside
1109 from the potential trap of not noticing that two successive entries
1110 identify the same location, this duplication impacts the time required
1111 to linearly scan the table, which is done in a number of places. So we
1112 just do one linear scan here and toss out the duplicates.
1114 Note that we are not concerned here about recovering the space that
1115 is potentially freed up, because the strings themselves are allocated
1116 on the storage_obstack, and will get automatically freed when the symbol
1117 table is freed. The caller can free up the unused minimal symbols at
1118 the end of the compacted region if their allocation strategy allows it.
1120 Also note we only go up to the next to last entry within the loop
1121 and then copy the last entry explicitly after the loop terminates.
1123 Since the different sources of information for each symbol may
1124 have different levels of "completeness", we may have duplicates
1125 that have one entry with type "mst_unknown" and the other with a
1126 known type. So if the one we are leaving alone has type mst_unknown,
1127 overwrite its type with the type from the one we are compacting out. */
1130 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1131 struct objfile *objfile)
1133 struct minimal_symbol *copyfrom;
1134 struct minimal_symbol *copyto;
1138 copyfrom = copyto = msymbol;
1139 while (copyfrom < msymbol + mcount - 1)
1141 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1142 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1143 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1144 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1145 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1147 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1149 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1154 *copyto++ = *copyfrom++;
1156 *copyto++ = *copyfrom++;
1157 mcount = copyto - msymbol;
1162 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1163 after compacting or sorting the table since the entries move around
1164 thus causing the internal minimal_symbol pointers to become jumbled. */
1167 build_minimal_symbol_hash_tables (struct objfile *objfile)
1170 struct minimal_symbol *msym;
1172 /* Clear the hash tables. */
1173 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1175 objfile->per_bfd->msymbol_hash[i] = 0;
1176 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1179 /* Now, (re)insert the actual entries. */
1180 for ((i = objfile->per_bfd->minimal_symbol_count,
1181 msym = objfile->per_bfd->msymbols);
1185 msym->hash_next = 0;
1186 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1188 msym->demangled_hash_next = 0;
1189 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1190 add_minsym_to_demangled_hash_table (msym,
1191 objfile->per_bfd->msymbol_demangled_hash);
1195 /* Add the minimal symbols in the existing bunches to the objfile's official
1196 minimal symbol table. In most cases there is no minimal symbol table yet
1197 for this objfile, and the existing bunches are used to create one. Once
1198 in a while (for shared libraries for example), we add symbols (e.g. common
1199 symbols) to an existing objfile.
1201 Because of the way minimal symbols are collected, we generally have no way
1202 of knowing what source language applies to any particular minimal symbol.
1203 Specifically, we have no way of knowing if the minimal symbol comes from a
1204 C++ compilation unit or not. So for the sake of supporting cached
1205 demangled C++ names, we have no choice but to try and demangle each new one
1206 that comes in. If the demangling succeeds, then we assume it is a C++
1207 symbol and set the symbol's language and demangled name fields
1208 appropriately. Note that in order to avoid unnecessary demanglings, and
1209 allocating obstack space that subsequently can't be freed for the demangled
1210 names, we mark all newly added symbols with language_auto. After
1211 compaction of the minimal symbols, we go back and scan the entire minimal
1212 symbol table looking for these new symbols. For each new symbol we attempt
1213 to demangle it, and if successful, record it as a language_cplus symbol
1214 and cache the demangled form on the symbol obstack. Symbols which don't
1215 demangle are marked as language_unknown symbols, which inhibits future
1216 attempts to demangle them if we later add more minimal symbols. */
1219 minimal_symbol_reader::install ()
1223 struct msym_bunch *bunch;
1224 struct minimal_symbol *msymbols;
1227 if (m_objfile->per_bfd->minsyms_read)
1230 if (m_msym_count > 0)
1232 if (symtab_create_debug)
1234 fprintf_unfiltered (gdb_stdlog,
1235 "Installing %d minimal symbols of objfile %s.\n",
1236 m_msym_count, objfile_name (m_objfile));
1239 /* Allocate enough space in the obstack, into which we will gather the
1240 bunches of new and existing minimal symbols, sort them, and then
1241 compact out the duplicate entries. Once we have a final table,
1242 we will give back the excess space. */
1244 alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count + 1;
1245 obstack_blank (&m_objfile->per_bfd->storage_obstack,
1246 alloc_count * sizeof (struct minimal_symbol));
1247 msymbols = (struct minimal_symbol *)
1248 obstack_base (&m_objfile->per_bfd->storage_obstack);
1250 /* Copy in the existing minimal symbols, if there are any. */
1252 if (m_objfile->per_bfd->minimal_symbol_count)
1253 memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols,
1254 m_objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol));
1256 /* Walk through the list of minimal symbol bunches, adding each symbol
1257 to the new contiguous array of symbols. Note that we start with the
1258 current, possibly partially filled bunch (thus we use the current
1259 msym_bunch_index for the first bunch we copy over), and thereafter
1260 each bunch is full. */
1262 mcount = m_objfile->per_bfd->minimal_symbol_count;
1264 for (bunch = m_msym_bunch; bunch != NULL; bunch = bunch->next)
1266 for (bindex = 0; bindex < m_msym_bunch_index; bindex++, mcount++)
1267 msymbols[mcount] = bunch->contents[bindex];
1268 m_msym_bunch_index = BUNCH_SIZE;
1271 /* Sort the minimal symbols by address. */
1273 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1274 compare_minimal_symbols);
1276 /* Compact out any duplicates, and free up whatever space we are
1279 mcount = compact_minimal_symbols (msymbols, mcount, m_objfile);
1281 obstack_blank_fast (&m_objfile->per_bfd->storage_obstack,
1282 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1283 msymbols = (struct minimal_symbol *)
1284 obstack_finish (&m_objfile->per_bfd->storage_obstack);
1286 /* We also terminate the minimal symbol table with a "null symbol",
1287 which is *not* included in the size of the table. This makes it
1288 easier to find the end of the table when we are handed a pointer
1289 to some symbol in the middle of it. Zero out the fields in the
1290 "null symbol" allocated at the end of the array. Note that the
1291 symbol count does *not* include this null symbol, which is why it
1292 is indexed by mcount and not mcount-1. */
1294 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1296 /* Attach the minimal symbol table to the specified objfile.
1297 The strings themselves are also located in the storage_obstack
1300 m_objfile->per_bfd->minimal_symbol_count = mcount;
1301 m_objfile->per_bfd->msymbols = msymbols;
1303 /* Now build the hash tables; we can't do this incrementally
1304 at an earlier point since we weren't finished with the obstack
1305 yet. (And if the msymbol obstack gets moved, all the internal
1306 pointers to other msymbols need to be adjusted.) */
1307 build_minimal_symbol_hash_tables (m_objfile);
1311 /* See minsyms.h. */
1314 terminate_minimal_symbol_table (struct objfile *objfile)
1316 if (! objfile->per_bfd->msymbols)
1317 objfile->per_bfd->msymbols
1318 = ((struct minimal_symbol *)
1319 obstack_alloc (&objfile->per_bfd->storage_obstack,
1320 sizeof (struct minimal_symbol)));
1323 struct minimal_symbol *m
1324 = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1326 memset (m, 0, sizeof (*m));
1327 /* Don't rely on these enumeration values being 0's. */
1328 MSYMBOL_TYPE (m) = mst_unknown;
1329 MSYMBOL_SET_LANGUAGE (m, language_unknown,
1330 &objfile->per_bfd->storage_obstack);
1334 /* Check if PC is in a shared library trampoline code stub.
1335 Return minimal symbol for the trampoline entry or NULL if PC is not
1336 in a trampoline code stub. */
1338 static struct minimal_symbol *
1339 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1341 struct obj_section *section = find_pc_section (pc);
1342 struct bound_minimal_symbol msymbol;
1344 if (section == NULL)
1346 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1348 if (msymbol.minsym != NULL
1349 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1350 return msymbol.minsym;
1354 /* If PC is in a shared library trampoline code stub, return the
1355 address of the `real' function belonging to the stub.
1356 Return 0 if PC is not in a trampoline code stub or if the real
1357 function is not found in the minimal symbol table.
1359 We may fail to find the right function if a function with the
1360 same name is defined in more than one shared library, but this
1361 is considered bad programming style. We could return 0 if we find
1362 a duplicate function in case this matters someday. */
1365 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1367 struct objfile *objfile;
1368 struct minimal_symbol *msymbol;
1369 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1371 if (tsymbol != NULL)
1373 ALL_MSYMBOLS (objfile, msymbol)
1375 if ((MSYMBOL_TYPE (msymbol) == mst_text
1376 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1377 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1378 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1379 return MSYMBOL_VALUE_ADDRESS (objfile, msymbol);
1381 /* Also handle minimal symbols pointing to function descriptors. */
1382 if (MSYMBOL_TYPE (msymbol) == mst_data
1383 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1384 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1388 func = gdbarch_convert_from_func_ptr_addr
1389 (get_objfile_arch (objfile),
1390 MSYMBOL_VALUE_ADDRESS (objfile, msymbol),
1393 /* Ignore data symbols that are not function descriptors. */
1394 if (func != MSYMBOL_VALUE_ADDRESS (objfile, msymbol))
1402 /* See minsyms.h. */
1405 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1409 struct obj_section *obj_section;
1411 struct minimal_symbol *msymbol;
1413 gdb_assert (minsym.minsym != NULL);
1415 /* If the minimal symbol has a size, use it. Otherwise use the
1416 lesser of the next minimal symbol in the same section, or the end
1417 of the section, as the end of the function. */
1419 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1420 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1422 /* Step over other symbols at this same address, and symbols in
1423 other sections, to find the next symbol in this section with a
1424 different address. */
1426 msymbol = minsym.minsym;
1427 section = MSYMBOL_SECTION (msymbol);
1428 for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1430 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1431 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1432 && MSYMBOL_SECTION (msymbol + i) == section)
1436 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1437 if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1438 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1439 < obj_section_endaddr (obj_section)))
1440 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
1442 /* We got the start address from the last msymbol in the objfile.
1443 So the end address is the end of the section. */
1444 result = obj_section_endaddr (obj_section);