1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
3 2002, 2003, 2004, 2007, 2008, 2009, 2010, 2011
4 Free Software Foundation, Inc.
5 Contributed by Cygnus Support, using pieces from other GDB modules.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 /* This file contains support routines for creating, manipulating, and
24 destroying minimal symbol tables.
26 Minimal symbol tables are used to hold some very basic information about
27 all defined global symbols (text, data, bss, abs, etc). The only two
28 required pieces of information are the symbol's name and the address
29 associated with that symbol.
31 In many cases, even if a file was compiled with no special options for
32 debugging at all, as long as was not stripped it will contain sufficient
33 information to build useful minimal symbol tables using this structure.
35 Even when a file contains enough debugging information to build a full
36 symbol table, these minimal symbols are still useful for quickly mapping
37 between names and addresses, and vice versa. They are also sometimes used
38 to figure out what full symbol table entries need to be read in. */
43 #include "gdb_string.h"
52 #include "cp-support.h"
55 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
56 At the end, copy them all into one newly allocated location on an objfile's
59 #define BUNCH_SIZE 127
63 struct msym_bunch *next;
64 struct minimal_symbol contents[BUNCH_SIZE];
67 /* Bunch currently being filled up.
68 The next field points to chain of filled bunches. */
70 static struct msym_bunch *msym_bunch;
72 /* Number of slots filled in current bunch. */
74 static int msym_bunch_index;
76 /* Total number of minimal symbols recorded so far for the objfile. */
78 static int msym_count;
80 /* Compute a hash code based using the same criteria as `strcmp_iw'. */
83 msymbol_hash_iw (const char *string)
85 unsigned int hash = 0;
87 while (*string && *string != '(')
89 while (isspace (*string))
91 if (*string && *string != '(')
93 hash = hash * 67 + *string - 113;
100 /* Compute a hash code for a string. */
103 msymbol_hash (const char *string)
105 unsigned int hash = 0;
107 for (; *string; ++string)
108 hash = hash * 67 + *string - 113;
112 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
114 add_minsym_to_hash_table (struct minimal_symbol *sym,
115 struct minimal_symbol **table)
117 if (sym->hash_next == NULL)
120 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
122 sym->hash_next = table[hash];
127 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
130 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
131 struct minimal_symbol **table)
133 if (sym->demangled_hash_next == NULL)
135 unsigned int hash = msymbol_hash_iw (SYMBOL_SEARCH_NAME (sym))
136 % MINIMAL_SYMBOL_HASH_SIZE;
138 sym->demangled_hash_next = table[hash];
144 /* Return OBJFILE where minimal symbol SYM is defined. */
146 msymbol_objfile (struct minimal_symbol *sym)
148 struct objfile *objf;
149 struct minimal_symbol *tsym;
152 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
154 for (objf = object_files; objf; objf = objf->next)
155 for (tsym = objf->msymbol_hash[hash]; tsym; tsym = tsym->hash_next)
159 /* We should always be able to find the objfile ... */
160 internal_error (__FILE__, __LINE__, _("failed internal consistency check"));
164 /* Look through all the current minimal symbol tables and find the
165 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
166 the search to that objfile. If SFILE is non-NULL, the only file-scope
167 symbols considered will be from that source file (global symbols are
168 still preferred). Returns a pointer to the minimal symbol that
169 matches, or NULL if no match is found.
171 Note: One instance where there may be duplicate minimal symbols with
172 the same name is when the symbol tables for a shared library and the
173 symbol tables for an executable contain global symbols with the same
174 names (the dynamic linker deals with the duplication).
176 It's also possible to have minimal symbols with different mangled
177 names, but identical demangled names. For example, the GNU C++ v3
178 ABI requires the generation of two (or perhaps three) copies of
179 constructor functions --- "in-charge", "not-in-charge", and
180 "allocate" copies; destructors may be duplicated as well.
181 Obviously, there must be distinct mangled names for each of these,
182 but the demangled names are all the same: S::S or S::~S. */
184 struct minimal_symbol *
185 lookup_minimal_symbol (const char *name, const char *sfile,
186 struct objfile *objf)
188 struct objfile *objfile;
189 struct minimal_symbol *msymbol;
190 struct minimal_symbol *found_symbol = NULL;
191 struct minimal_symbol *found_file_symbol = NULL;
192 struct minimal_symbol *trampoline_symbol = NULL;
194 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
195 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
197 int needtofreename = 0;
198 const char *modified_name;
201 sfile = lbasename (sfile);
203 /* For C++, canonicalize the input name. */
204 modified_name = name;
205 if (current_language->la_language == language_cplus)
207 char *cname = cp_canonicalize_string (name);
211 modified_name = cname;
216 for (objfile = object_files;
217 objfile != NULL && found_symbol == NULL;
218 objfile = objfile->next)
220 if (objf == NULL || objf == objfile
221 || objf == objfile->separate_debug_objfile_backlink)
223 /* Do two passes: the first over the ordinary hash table,
224 and the second over the demangled hash table. */
227 for (pass = 1; pass <= 2 && found_symbol == NULL; pass++)
229 /* Select hash list according to pass. */
231 msymbol = objfile->msymbol_hash[hash];
233 msymbol = objfile->msymbol_demangled_hash[dem_hash];
235 while (msymbol != NULL && found_symbol == NULL)
241 match = strcmp (SYMBOL_LINKAGE_NAME (msymbol),
246 match = SYMBOL_MATCHES_SEARCH_NAME (msymbol,
252 switch (MSYMBOL_TYPE (msymbol))
258 || strcmp (msymbol->filename, sfile) == 0)
259 found_file_symbol = msymbol;
262 case mst_solib_trampoline:
264 /* If a trampoline symbol is found, we prefer to
265 keep looking for the *real* symbol. If the
266 actual symbol is not found, then we'll use the
268 if (trampoline_symbol == NULL)
269 trampoline_symbol = msymbol;
274 found_symbol = msymbol;
279 /* Find the next symbol on the hash chain. */
281 msymbol = msymbol->hash_next;
283 msymbol = msymbol->demangled_hash_next;
290 xfree ((void *) modified_name);
292 /* External symbols are best. */
296 /* File-local symbols are next best. */
297 if (found_file_symbol)
298 return found_file_symbol;
300 /* Symbols for shared library trampolines are next best. */
301 if (trampoline_symbol)
302 return trampoline_symbol;
307 /* Look through all the current minimal symbol tables and find the
308 first minimal symbol that matches NAME and has text type. If OBJF
309 is non-NULL, limit the search to that objfile. Returns a pointer
310 to the minimal symbol that matches, or NULL if no match is found.
312 This function only searches the mangled (linkage) names. */
314 struct minimal_symbol *
315 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
317 struct objfile *objfile;
318 struct minimal_symbol *msymbol;
319 struct minimal_symbol *found_symbol = NULL;
320 struct minimal_symbol *found_file_symbol = NULL;
322 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
324 for (objfile = object_files;
325 objfile != NULL && found_symbol == NULL;
326 objfile = objfile->next)
328 if (objf == NULL || objf == objfile
329 || objf == objfile->separate_debug_objfile_backlink)
331 for (msymbol = objfile->msymbol_hash[hash];
332 msymbol != NULL && found_symbol == NULL;
333 msymbol = msymbol->hash_next)
335 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
336 (MSYMBOL_TYPE (msymbol) == mst_text ||
337 MSYMBOL_TYPE (msymbol) == mst_file_text))
339 switch (MSYMBOL_TYPE (msymbol))
342 found_file_symbol = msymbol;
345 found_symbol = msymbol;
352 /* External symbols are best. */
356 /* File-local symbols are next best. */
357 if (found_file_symbol)
358 return found_file_symbol;
363 /* Look through all the current minimal symbol tables and find the
364 first minimal symbol that matches NAME and PC. If OBJF is non-NULL,
365 limit the search to that objfile. Returns a pointer to the minimal
366 symbol that matches, or NULL if no match is found. */
368 struct minimal_symbol *
369 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
370 struct objfile *objf)
372 struct objfile *objfile;
373 struct minimal_symbol *msymbol;
375 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
377 for (objfile = object_files;
379 objfile = objfile->next)
381 if (objf == NULL || objf == objfile
382 || objf == objfile->separate_debug_objfile_backlink)
384 for (msymbol = objfile->msymbol_hash[hash];
386 msymbol = msymbol->hash_next)
388 if (SYMBOL_VALUE_ADDRESS (msymbol) == pc
389 && strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0)
398 /* Look through all the current minimal symbol tables and find the
399 first minimal symbol that matches NAME and is a solib trampoline.
400 If OBJF is non-NULL, limit the search to that objfile. Returns a
401 pointer to the minimal symbol that matches, or NULL if no match is
404 This function only searches the mangled (linkage) names. */
406 struct minimal_symbol *
407 lookup_minimal_symbol_solib_trampoline (const char *name,
408 struct objfile *objf)
410 struct objfile *objfile;
411 struct minimal_symbol *msymbol;
412 struct minimal_symbol *found_symbol = NULL;
414 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
416 for (objfile = object_files;
417 objfile != NULL && found_symbol == NULL;
418 objfile = objfile->next)
420 if (objf == NULL || objf == objfile
421 || objf == objfile->separate_debug_objfile_backlink)
423 for (msymbol = objfile->msymbol_hash[hash];
424 msymbol != NULL && found_symbol == NULL;
425 msymbol = msymbol->hash_next)
427 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
428 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
437 /* Search through the minimal symbol table for each objfile and find
438 the symbol whose address is the largest address that is still less
439 than or equal to PC, and matches SECTION (which is not NULL).
440 Returns a pointer to the minimal symbol if such a symbol is found,
441 or NULL if PC is not in a suitable range.
442 Note that we need to look through ALL the minimal symbol tables
443 before deciding on the symbol that comes closest to the specified PC.
444 This is because objfiles can overlap, for example objfile A has .text
445 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
448 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
449 there are text and trampoline symbols at the same address.
450 Otherwise prefer mst_text symbols. */
452 static struct minimal_symbol *
453 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc,
454 struct obj_section *section,
460 struct objfile *objfile;
461 struct minimal_symbol *msymbol;
462 struct minimal_symbol *best_symbol = NULL;
463 enum minimal_symbol_type want_type, other_type;
465 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
466 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
468 /* We can not require the symbol found to be in section, because
469 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
470 symbol - but find_pc_section won't return an absolute section and
471 hence the code below would skip over absolute symbols. We can
472 still take advantage of the call to find_pc_section, though - the
473 object file still must match. In case we have separate debug
474 files, search both the file and its separate debug file. There's
475 no telling which one will have the minimal symbols. */
477 gdb_assert (section != NULL);
479 for (objfile = section->objfile;
481 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
483 /* If this objfile has a minimal symbol table, go search it using
484 a binary search. Note that a minimal symbol table always consists
485 of at least two symbols, a "real" symbol and the terminating
486 "null symbol". If there are no real symbols, then there is no
487 minimal symbol table at all. */
489 if (objfile->minimal_symbol_count > 0)
491 int best_zero_sized = -1;
493 msymbol = objfile->msymbols;
495 hi = objfile->minimal_symbol_count - 1;
497 /* This code assumes that the minimal symbols are sorted by
498 ascending address values. If the pc value is greater than or
499 equal to the first symbol's address, then some symbol in this
500 minimal symbol table is a suitable candidate for being the
501 "best" symbol. This includes the last real symbol, for cases
502 where the pc value is larger than any address in this vector.
504 By iterating until the address associated with the current
505 hi index (the endpoint of the test interval) is less than
506 or equal to the desired pc value, we accomplish two things:
507 (1) the case where the pc value is larger than any minimal
508 symbol address is trivially solved, (2) the address associated
509 with the hi index is always the one we want when the interation
510 terminates. In essence, we are iterating the test interval
511 down until the pc value is pushed out of it from the high end.
513 Warning: this code is trickier than it would appear at first. */
515 /* Should also require that pc is <= end of objfile. FIXME! */
516 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
518 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
520 /* pc is still strictly less than highest address. */
521 /* Note "new" will always be >= lo. */
523 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
534 /* If we have multiple symbols at the same address, we want
535 hi to point to the last one. That way we can find the
536 right symbol if it has an index greater than hi. */
537 while (hi < objfile->minimal_symbol_count - 1
538 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
539 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
542 /* Skip various undesirable symbols. */
545 /* Skip any absolute symbols. This is apparently
546 what adb and dbx do, and is needed for the CM-5.
547 There are two known possible problems: (1) on
548 ELF, apparently end, edata, etc. are absolute.
549 Not sure ignoring them here is a big deal, but if
550 we want to use them, the fix would go in
551 elfread.c. (2) I think shared library entry
552 points on the NeXT are absolute. If we want
553 special handling for this it probably should be
554 triggered by a special mst_abs_or_lib or some
557 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
563 /* If SECTION was specified, skip any symbol from
566 /* Some types of debug info, such as COFF,
567 don't fill the bfd_section member, so don't
568 throw away symbols on those platforms. */
569 && SYMBOL_OBJ_SECTION (&msymbol[hi]) != NULL
570 && (!matching_obj_sections
571 (SYMBOL_OBJ_SECTION (&msymbol[hi]), section)))
577 /* If we are looking for a trampoline and this is a
578 text symbol, or the other way around, check the
579 preceeding symbol too. If they are otherwise
580 identical prefer that one. */
582 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
583 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
584 && (MSYMBOL_SIZE (&msymbol[hi])
585 == MSYMBOL_SIZE (&msymbol[hi - 1]))
586 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
587 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
588 && (SYMBOL_OBJ_SECTION (&msymbol[hi])
589 == SYMBOL_OBJ_SECTION (&msymbol[hi - 1])))
595 /* If the minimal symbol has a zero size, save it
596 but keep scanning backwards looking for one with
597 a non-zero size. A zero size may mean that the
598 symbol isn't an object or function (e.g. a
599 label), or it may just mean that the size was not
601 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
602 && best_zero_sized == -1)
604 best_zero_sized = hi;
609 /* If we are past the end of the current symbol, try
610 the previous symbol if it has a larger overlapping
611 size. This happens on i686-pc-linux-gnu with glibc;
612 the nocancel variants of system calls are inside
613 the cancellable variants, but both have sizes. */
615 && MSYMBOL_SIZE (&msymbol[hi]) != 0
616 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
617 + MSYMBOL_SIZE (&msymbol[hi]))
618 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
619 + MSYMBOL_SIZE (&msymbol[hi - 1])))
625 /* Otherwise, this symbol must be as good as we're going
630 /* If HI has a zero size, and best_zero_sized is set,
631 then we had two or more zero-sized symbols; prefer
632 the first one we found (which may have a higher
633 address). Also, if we ran off the end, be sure
635 if (best_zero_sized != -1
636 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
637 hi = best_zero_sized;
639 /* If the minimal symbol has a non-zero size, and this
640 PC appears to be outside the symbol's contents, then
641 refuse to use this symbol. If we found a zero-sized
642 symbol with an address greater than this symbol's,
643 use that instead. We assume that if symbols have
644 specified sizes, they do not overlap. */
647 && MSYMBOL_SIZE (&msymbol[hi]) != 0
648 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
649 + MSYMBOL_SIZE (&msymbol[hi])))
651 if (best_zero_sized != -1)
652 hi = best_zero_sized;
654 /* Go on to the next object file. */
658 /* The minimal symbol indexed by hi now is the best one in this
659 objfile's minimal symbol table. See if it is the best one
663 && ((best_symbol == NULL) ||
664 (SYMBOL_VALUE_ADDRESS (best_symbol) <
665 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
667 best_symbol = &msymbol[hi];
672 return (best_symbol);
675 struct minimal_symbol *
676 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
680 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
681 force the section but that (well unless you're doing overlay
682 debugging) always returns NULL making the call somewhat useless. */
683 section = find_pc_section (pc);
687 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
690 /* Backward compatibility: search through the minimal symbol table
691 for a matching PC (no section given). */
693 struct minimal_symbol *
694 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
696 return lookup_minimal_symbol_by_pc_section (pc, NULL);
699 /* Find the minimal symbol named NAME, and return both the minsym
700 struct and its objfile. This only checks the linkage name. Sets
701 *OBJFILE_P and returns the minimal symbol, if it is found. If it
702 is not found, returns NULL. */
704 struct minimal_symbol *
705 lookup_minimal_symbol_and_objfile (const char *name,
706 struct objfile **objfile_p)
708 struct objfile *objfile;
709 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
711 ALL_OBJFILES (objfile)
713 struct minimal_symbol *msym;
715 for (msym = objfile->msymbol_hash[hash];
717 msym = msym->hash_next)
719 if (strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
721 *objfile_p = objfile;
731 /* Return leading symbol character for a BFD. If BFD is NULL,
732 return the leading symbol character from the main objfile. */
734 static int get_symbol_leading_char (bfd *);
737 get_symbol_leading_char (bfd *abfd)
740 return bfd_get_symbol_leading_char (abfd);
741 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
742 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
746 /* Prepare to start collecting minimal symbols. Note that presetting
747 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
748 symbol to allocate the memory for the first bunch. */
751 init_minimal_symbol_collection (void)
755 msym_bunch_index = BUNCH_SIZE;
759 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
760 enum minimal_symbol_type ms_type,
761 struct objfile *objfile)
769 case mst_solib_trampoline:
770 section = SECT_OFF_TEXT (objfile);
774 section = SECT_OFF_DATA (objfile);
778 section = SECT_OFF_BSS (objfile);
784 prim_record_minimal_symbol_and_info (name, address, ms_type,
785 section, NULL, objfile);
788 /* Record a minimal symbol in the msym bunches. Returns the symbol
791 struct minimal_symbol *
792 prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
794 enum minimal_symbol_type ms_type,
796 asection *bfd_section,
797 struct objfile *objfile)
799 struct obj_section *obj_section;
800 struct msym_bunch *new;
801 struct minimal_symbol *msymbol;
803 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
804 the minimal symbols, because if there is also another symbol
805 at the same address (e.g. the first function of the file),
806 lookup_minimal_symbol_by_pc would have no way of getting the
808 if (ms_type == mst_file_text && name[0] == 'g'
809 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
810 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
813 /* It's safe to strip the leading char here once, since the name
814 is also stored stripped in the minimal symbol table. */
815 if (name[0] == get_symbol_leading_char (objfile->obfd))
821 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
824 if (msym_bunch_index == BUNCH_SIZE)
826 new = XCALLOC (1, struct msym_bunch);
827 msym_bunch_index = 0;
828 new->next = msym_bunch;
831 msymbol = &msym_bunch->contents[msym_bunch_index];
832 SYMBOL_SET_LANGUAGE (msymbol, language_auto);
833 SYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, objfile);
835 SYMBOL_VALUE_ADDRESS (msymbol) = address;
836 SYMBOL_SECTION (msymbol) = section;
837 SYMBOL_OBJ_SECTION (msymbol) = NULL;
839 /* Find obj_section corresponding to bfd_section. */
841 ALL_OBJFILE_OSECTIONS (objfile, obj_section)
843 if (obj_section->the_bfd_section == bfd_section)
845 SYMBOL_OBJ_SECTION (msymbol) = obj_section;
850 MSYMBOL_TYPE (msymbol) = ms_type;
851 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
852 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
853 MSYMBOL_SIZE (msymbol) = 0;
855 /* The hash pointers must be cleared! If they're not,
856 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
857 msymbol->hash_next = NULL;
858 msymbol->demangled_hash_next = NULL;
862 OBJSTAT (objfile, n_minsyms++);
866 /* Record a minimal symbol in the msym bunches. Returns the symbol
869 struct minimal_symbol *
870 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
871 enum minimal_symbol_type ms_type,
873 asection *bfd_section,
874 struct objfile *objfile)
876 return prim_record_minimal_symbol_full (name, strlen (name), 1,
877 address, ms_type, section,
878 bfd_section, objfile);
881 /* Compare two minimal symbols by address and return a signed result based
882 on unsigned comparisons, so that we sort into unsigned numeric order.
883 Within groups with the same address, sort by name. */
886 compare_minimal_symbols (const void *fn1p, const void *fn2p)
888 const struct minimal_symbol *fn1;
889 const struct minimal_symbol *fn2;
891 fn1 = (const struct minimal_symbol *) fn1p;
892 fn2 = (const struct minimal_symbol *) fn2p;
894 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
896 return (-1); /* addr 1 is less than addr 2. */
898 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
900 return (1); /* addr 1 is greater than addr 2. */
903 /* addrs are equal: sort by name */
905 char *name1 = SYMBOL_LINKAGE_NAME (fn1);
906 char *name2 = SYMBOL_LINKAGE_NAME (fn2);
908 if (name1 && name2) /* both have names */
909 return strcmp (name1, name2);
911 return 1; /* fn1 has no name, so it is "less". */
912 else if (name1) /* fn2 has no name, so it is "less". */
915 return (0); /* Neither has a name, so they're equal. */
919 /* Discard the currently collected minimal symbols, if any. If we wish
920 to save them for later use, we must have already copied them somewhere
921 else before calling this function.
923 FIXME: We could allocate the minimal symbol bunches on their own
924 obstack and then simply blow the obstack away when we are done with
925 it. Is it worth the extra trouble though? */
928 do_discard_minimal_symbols_cleanup (void *arg)
930 struct msym_bunch *next;
932 while (msym_bunch != NULL)
934 next = msym_bunch->next;
941 make_cleanup_discard_minimal_symbols (void)
943 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
948 /* Compact duplicate entries out of a minimal symbol table by walking
949 through the table and compacting out entries with duplicate addresses
950 and matching names. Return the number of entries remaining.
952 On entry, the table resides between msymbol[0] and msymbol[mcount].
953 On exit, it resides between msymbol[0] and msymbol[result_count].
955 When files contain multiple sources of symbol information, it is
956 possible for the minimal symbol table to contain many duplicate entries.
957 As an example, SVR4 systems use ELF formatted object files, which
958 usually contain at least two different types of symbol tables (a
959 standard ELF one and a smaller dynamic linking table), as well as
960 DWARF debugging information for files compiled with -g.
962 Without compacting, the minimal symbol table for gdb itself contains
963 over a 1000 duplicates, about a third of the total table size. Aside
964 from the potential trap of not noticing that two successive entries
965 identify the same location, this duplication impacts the time required
966 to linearly scan the table, which is done in a number of places. So we
967 just do one linear scan here and toss out the duplicates.
969 Note that we are not concerned here about recovering the space that
970 is potentially freed up, because the strings themselves are allocated
971 on the objfile_obstack, and will get automatically freed when the symbol
972 table is freed. The caller can free up the unused minimal symbols at
973 the end of the compacted region if their allocation strategy allows it.
975 Also note we only go up to the next to last entry within the loop
976 and then copy the last entry explicitly after the loop terminates.
978 Since the different sources of information for each symbol may
979 have different levels of "completeness", we may have duplicates
980 that have one entry with type "mst_unknown" and the other with a
981 known type. So if the one we are leaving alone has type mst_unknown,
982 overwrite its type with the type from the one we are compacting out. */
985 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
986 struct objfile *objfile)
988 struct minimal_symbol *copyfrom;
989 struct minimal_symbol *copyto;
993 copyfrom = copyto = msymbol;
994 while (copyfrom < msymbol + mcount - 1)
996 if (SYMBOL_VALUE_ADDRESS (copyfrom)
997 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
998 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
999 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1001 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1003 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1008 *copyto++ = *copyfrom++;
1010 *copyto++ = *copyfrom++;
1011 mcount = copyto - msymbol;
1016 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1017 after compacting or sorting the table since the entries move around
1018 thus causing the internal minimal_symbol pointers to become jumbled. */
1021 build_minimal_symbol_hash_tables (struct objfile *objfile)
1024 struct minimal_symbol *msym;
1026 /* Clear the hash tables. */
1027 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1029 objfile->msymbol_hash[i] = 0;
1030 objfile->msymbol_demangled_hash[i] = 0;
1033 /* Now, (re)insert the actual entries. */
1034 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
1038 msym->hash_next = 0;
1039 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
1041 msym->demangled_hash_next = 0;
1042 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
1043 add_minsym_to_demangled_hash_table (msym,
1044 objfile->msymbol_demangled_hash);
1048 /* Add the minimal symbols in the existing bunches to the objfile's official
1049 minimal symbol table. In most cases there is no minimal symbol table yet
1050 for this objfile, and the existing bunches are used to create one. Once
1051 in a while (for shared libraries for example), we add symbols (e.g. common
1052 symbols) to an existing objfile.
1054 Because of the way minimal symbols are collected, we generally have no way
1055 of knowing what source language applies to any particular minimal symbol.
1056 Specifically, we have no way of knowing if the minimal symbol comes from a
1057 C++ compilation unit or not. So for the sake of supporting cached
1058 demangled C++ names, we have no choice but to try and demangle each new one
1059 that comes in. If the demangling succeeds, then we assume it is a C++
1060 symbol and set the symbol's language and demangled name fields
1061 appropriately. Note that in order to avoid unnecessary demanglings, and
1062 allocating obstack space that subsequently can't be freed for the demangled
1063 names, we mark all newly added symbols with language_auto. After
1064 compaction of the minimal symbols, we go back and scan the entire minimal
1065 symbol table looking for these new symbols. For each new symbol we attempt
1066 to demangle it, and if successful, record it as a language_cplus symbol
1067 and cache the demangled form on the symbol obstack. Symbols which don't
1068 demangle are marked as language_unknown symbols, which inhibits future
1069 attempts to demangle them if we later add more minimal symbols. */
1072 install_minimal_symbols (struct objfile *objfile)
1076 struct msym_bunch *bunch;
1077 struct minimal_symbol *msymbols;
1082 /* Allocate enough space in the obstack, into which we will gather the
1083 bunches of new and existing minimal symbols, sort them, and then
1084 compact out the duplicate entries. Once we have a final table,
1085 we will give back the excess space. */
1087 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
1088 obstack_blank (&objfile->objfile_obstack,
1089 alloc_count * sizeof (struct minimal_symbol));
1090 msymbols = (struct minimal_symbol *)
1091 obstack_base (&objfile->objfile_obstack);
1093 /* Copy in the existing minimal symbols, if there are any. */
1095 if (objfile->minimal_symbol_count)
1096 memcpy ((char *) msymbols, (char *) objfile->msymbols,
1097 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
1099 /* Walk through the list of minimal symbol bunches, adding each symbol
1100 to the new contiguous array of symbols. Note that we start with the
1101 current, possibly partially filled bunch (thus we use the current
1102 msym_bunch_index for the first bunch we copy over), and thereafter
1103 each bunch is full. */
1105 mcount = objfile->minimal_symbol_count;
1107 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1109 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1110 msymbols[mcount] = bunch->contents[bindex];
1111 msym_bunch_index = BUNCH_SIZE;
1114 /* Sort the minimal symbols by address. */
1116 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1117 compare_minimal_symbols);
1119 /* Compact out any duplicates, and free up whatever space we are
1122 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1124 obstack_blank (&objfile->objfile_obstack,
1125 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1126 msymbols = (struct minimal_symbol *)
1127 obstack_finish (&objfile->objfile_obstack);
1129 /* We also terminate the minimal symbol table with a "null symbol",
1130 which is *not* included in the size of the table. This makes it
1131 easier to find the end of the table when we are handed a pointer
1132 to some symbol in the middle of it. Zero out the fields in the
1133 "null symbol" allocated at the end of the array. Note that the
1134 symbol count does *not* include this null symbol, which is why it
1135 is indexed by mcount and not mcount-1. */
1137 SYMBOL_LINKAGE_NAME (&msymbols[mcount]) = NULL;
1138 SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0;
1139 MSYMBOL_TARGET_FLAG_1 (&msymbols[mcount]) = 0;
1140 MSYMBOL_TARGET_FLAG_2 (&msymbols[mcount]) = 0;
1141 MSYMBOL_SIZE (&msymbols[mcount]) = 0;
1142 MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown;
1143 SYMBOL_SET_LANGUAGE (&msymbols[mcount], language_unknown);
1145 /* Attach the minimal symbol table to the specified objfile.
1146 The strings themselves are also located in the objfile_obstack
1149 objfile->minimal_symbol_count = mcount;
1150 objfile->msymbols = msymbols;
1152 /* Try to guess the appropriate C++ ABI by looking at the names
1153 of the minimal symbols in the table. */
1157 for (i = 0; i < mcount; i++)
1159 /* If a symbol's name starts with _Z and was successfully
1160 demangled, then we can assume we've found a GNU v3 symbol.
1161 For now we set the C++ ABI globally; if the user is
1162 mixing ABIs then the user will need to "set cp-abi"
1164 const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]);
1166 if (name[0] == '_' && name[1] == 'Z'
1167 && SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL)
1169 set_cp_abi_as_auto_default ("gnu-v3");
1175 /* Now build the hash tables; we can't do this incrementally
1176 at an earlier point since we weren't finished with the obstack
1177 yet. (And if the msymbol obstack gets moved, all the internal
1178 pointers to other msymbols need to be adjusted.) */
1179 build_minimal_symbol_hash_tables (objfile);
1183 /* Sort all the minimal symbols in OBJFILE. */
1186 msymbols_sort (struct objfile *objfile)
1188 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1189 sizeof (struct minimal_symbol), compare_minimal_symbols);
1190 build_minimal_symbol_hash_tables (objfile);
1193 /* Check if PC is in a shared library trampoline code stub.
1194 Return minimal symbol for the trampoline entry or NULL if PC is not
1195 in a trampoline code stub. */
1197 struct minimal_symbol *
1198 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1200 struct obj_section *section = find_pc_section (pc);
1201 struct minimal_symbol *msymbol;
1203 if (section == NULL)
1205 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1207 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
1212 /* If PC is in a shared library trampoline code stub, return the
1213 address of the `real' function belonging to the stub.
1214 Return 0 if PC is not in a trampoline code stub or if the real
1215 function is not found in the minimal symbol table.
1217 We may fail to find the right function if a function with the
1218 same name is defined in more than one shared library, but this
1219 is considered bad programming style. We could return 0 if we find
1220 a duplicate function in case this matters someday. */
1223 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1225 struct objfile *objfile;
1226 struct minimal_symbol *msymbol;
1227 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1229 if (tsymbol != NULL)
1231 ALL_MSYMBOLS (objfile, msymbol)
1233 if (MSYMBOL_TYPE (msymbol) == mst_text
1234 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1235 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1236 return SYMBOL_VALUE_ADDRESS (msymbol);
1238 /* Also handle minimal symbols pointing to function descriptors. */
1239 if (MSYMBOL_TYPE (msymbol) == mst_data
1240 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1241 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1245 func = gdbarch_convert_from_func_ptr_addr
1246 (get_objfile_arch (objfile),
1247 SYMBOL_VALUE_ADDRESS (msymbol),
1250 /* Ignore data symbols that are not function descriptors. */
1251 if (func != SYMBOL_VALUE_ADDRESS (msymbol))