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 Free Software Foundation, Inc.
4 Contributed by Cygnus Support, using pieces from other GDB modules.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 /* This file contains support routines for creating, manipulating, and
23 destroying minimal symbol tables.
25 Minimal symbol tables are used to hold some very basic information about
26 all defined global symbols (text, data, bss, abs, etc). The only two
27 required pieces of information are the symbol's name and the address
28 associated with that symbol.
30 In many cases, even if a file was compiled with no special options for
31 debugging at all, as long as was not stripped it will contain sufficient
32 information to build useful minimal symbol tables using this structure.
34 Even when a file contains enough debugging information to build a full
35 symbol table, these minimal symbols are still useful for quickly mapping
36 between names and addresses, and vice versa. They are also sometimes used
37 to figure out what full symbol table entries need to be read in. */
42 #include "gdb_string.h"
51 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
52 At the end, copy them all into one newly allocated location on an objfile's
55 #define BUNCH_SIZE 127
59 struct msym_bunch *next;
60 struct minimal_symbol contents[BUNCH_SIZE];
63 /* Bunch currently being filled up.
64 The next field points to chain of filled bunches. */
66 static struct msym_bunch *msym_bunch;
68 /* Number of slots filled in current bunch. */
70 static int msym_bunch_index;
72 /* Total number of minimal symbols recorded so far for the objfile. */
74 static int msym_count;
76 /* Compute a hash code based using the same criteria as `strcmp_iw'. */
79 msymbol_hash_iw (const char *string)
81 unsigned int hash = 0;
82 while (*string && *string != '(')
84 while (isspace (*string))
86 if (*string && *string != '(')
88 hash = hash * 67 + *string - 113;
95 /* Compute a hash code for a string. */
98 msymbol_hash (const char *string)
100 unsigned int hash = 0;
101 for (; *string; ++string)
102 hash = hash * 67 + *string - 113;
106 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
108 add_minsym_to_hash_table (struct minimal_symbol *sym,
109 struct minimal_symbol **table)
111 if (sym->hash_next == NULL)
114 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
115 sym->hash_next = table[hash];
120 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
123 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
124 struct minimal_symbol **table)
126 if (sym->demangled_hash_next == NULL)
128 unsigned int hash = msymbol_hash_iw (SYMBOL_DEMANGLED_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
129 sym->demangled_hash_next = table[hash];
135 /* Return OBJFILE where minimal symbol SYM is defined. */
137 msymbol_objfile (struct minimal_symbol *sym)
139 struct objfile *objf;
140 struct minimal_symbol *tsym;
143 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
145 for (objf = object_files; objf; objf = objf->next)
146 for (tsym = objf->msymbol_hash[hash]; tsym; tsym = tsym->hash_next)
150 /* We should always be able to find the objfile ... */
151 internal_error (__FILE__, __LINE__, _("failed internal consistency check"));
155 /* Look through all the current minimal symbol tables and find the
156 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
157 the search to that objfile. If SFILE is non-NULL, the only file-scope
158 symbols considered will be from that source file (global symbols are
159 still preferred). Returns a pointer to the minimal symbol that
160 matches, or NULL if no match is found.
162 Note: One instance where there may be duplicate minimal symbols with
163 the same name is when the symbol tables for a shared library and the
164 symbol tables for an executable contain global symbols with the same
165 names (the dynamic linker deals with the duplication).
167 It's also possible to have minimal symbols with different mangled
168 names, but identical demangled names. For example, the GNU C++ v3
169 ABI requires the generation of two (or perhaps three) copies of
170 constructor functions --- "in-charge", "not-in-charge", and
171 "allocate" copies; destructors may be duplicated as well.
172 Obviously, there must be distinct mangled names for each of these,
173 but the demangled names are all the same: S::S or S::~S. */
175 struct minimal_symbol *
176 lookup_minimal_symbol (const char *name, const char *sfile,
177 struct objfile *objf)
179 struct objfile *objfile;
180 struct minimal_symbol *msymbol;
181 struct minimal_symbol *found_symbol = NULL;
182 struct minimal_symbol *found_file_symbol = NULL;
183 struct minimal_symbol *trampoline_symbol = NULL;
185 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
186 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
190 char *p = strrchr (sfile, '/');
195 for (objfile = object_files;
196 objfile != NULL && found_symbol == NULL;
197 objfile = objfile->next)
199 if (objf == NULL || objf == objfile
200 || objf->separate_debug_objfile == objfile)
202 /* Do two passes: the first over the ordinary hash table,
203 and the second over the demangled hash table. */
206 for (pass = 1; pass <= 2 && found_symbol == NULL; pass++)
208 /* Select hash list according to pass. */
210 msymbol = objfile->msymbol_hash[hash];
212 msymbol = objfile->msymbol_demangled_hash[dem_hash];
214 while (msymbol != NULL && found_symbol == NULL)
216 /* FIXME: carlton/2003-02-27: This is an unholy
217 mixture of linkage names and natural names. If
218 you want to test the linkage names with strcmp,
219 do that. If you want to test the natural names
220 with strcmp_iw, use SYMBOL_MATCHES_NATURAL_NAME. */
221 if (strcmp (DEPRECATED_SYMBOL_NAME (msymbol), (name)) == 0
222 || (SYMBOL_DEMANGLED_NAME (msymbol) != NULL
223 && strcmp_iw (SYMBOL_DEMANGLED_NAME (msymbol),
226 switch (MSYMBOL_TYPE (msymbol))
232 || strcmp (msymbol->filename, sfile) == 0)
233 found_file_symbol = msymbol;
236 case mst_solib_trampoline:
238 /* If a trampoline symbol is found, we prefer to
239 keep looking for the *real* symbol. If the
240 actual symbol is not found, then we'll use the
242 if (trampoline_symbol == NULL)
243 trampoline_symbol = msymbol;
248 found_symbol = msymbol;
253 /* Find the next symbol on the hash chain. */
255 msymbol = msymbol->hash_next;
257 msymbol = msymbol->demangled_hash_next;
262 /* External symbols are best. */
266 /* File-local symbols are next best. */
267 if (found_file_symbol)
268 return found_file_symbol;
270 /* Symbols for shared library trampolines are next best. */
271 if (trampoline_symbol)
272 return trampoline_symbol;
277 /* Look through all the current minimal symbol tables and find the
278 first minimal symbol that matches NAME and has text type. If OBJF
279 is non-NULL, limit the search to that objfile. Returns a pointer
280 to the minimal symbol that matches, or NULL if no match is found.
282 This function only searches the mangled (linkage) names. */
284 struct minimal_symbol *
285 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
287 struct objfile *objfile;
288 struct minimal_symbol *msymbol;
289 struct minimal_symbol *found_symbol = NULL;
290 struct minimal_symbol *found_file_symbol = NULL;
292 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
294 for (objfile = object_files;
295 objfile != NULL && found_symbol == NULL;
296 objfile = objfile->next)
298 if (objf == NULL || objf == objfile
299 || objf->separate_debug_objfile == objfile)
301 for (msymbol = objfile->msymbol_hash[hash];
302 msymbol != NULL && found_symbol == NULL;
303 msymbol = msymbol->hash_next)
305 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
306 (MSYMBOL_TYPE (msymbol) == mst_text ||
307 MSYMBOL_TYPE (msymbol) == mst_file_text))
309 switch (MSYMBOL_TYPE (msymbol))
312 found_file_symbol = msymbol;
315 found_symbol = msymbol;
322 /* External symbols are best. */
326 /* File-local symbols are next best. */
327 if (found_file_symbol)
328 return found_file_symbol;
333 /* Look through all the current minimal symbol tables and find the
334 first minimal symbol that matches NAME and is a solib trampoline.
335 If OBJF is non-NULL, limit the search to that objfile. Returns a
336 pointer to the minimal symbol that matches, or NULL if no match is
339 This function only searches the mangled (linkage) names. */
341 struct minimal_symbol *
342 lookup_minimal_symbol_solib_trampoline (const char *name,
343 struct objfile *objf)
345 struct objfile *objfile;
346 struct minimal_symbol *msymbol;
347 struct minimal_symbol *found_symbol = NULL;
349 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
351 for (objfile = object_files;
352 objfile != NULL && found_symbol == NULL;
353 objfile = objfile->next)
355 if (objf == NULL || objf == objfile
356 || objf->separate_debug_objfile == objfile)
358 for (msymbol = objfile->msymbol_hash[hash];
359 msymbol != NULL && found_symbol == NULL;
360 msymbol = msymbol->hash_next)
362 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
363 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
372 /* Search through the minimal symbol table for each objfile and find
373 the symbol whose address is the largest address that is still less
374 than or equal to PC, and matches SECTION (if non-NULL). Returns a
375 pointer to the minimal symbol if such a symbol is found, or NULL if
376 PC is not in a suitable range. Note that we need to look through
377 ALL the minimal symbol tables before deciding on the symbol that
378 comes closest to the specified PC. This is because objfiles can
379 overlap, for example objfile A has .text at 0x100 and .data at
380 0x40000 and objfile B has .text at 0x234 and .data at 0x40048.
382 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
383 there are text and trampoline symbols at the same address.
384 Otherwise prefer mst_text symbols. */
386 static struct minimal_symbol *
387 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc, asection *section,
393 struct objfile *objfile;
394 struct minimal_symbol *msymbol;
395 struct minimal_symbol *best_symbol = NULL;
396 struct obj_section *pc_section;
397 enum minimal_symbol_type want_type, other_type;
399 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
400 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
402 /* PC has to be in a known section. This ensures that anything
403 beyond the end of the last segment doesn't appear to be part of
404 the last function in the last segment. */
405 pc_section = find_pc_section (pc);
406 if (pc_section == NULL)
409 /* We can not require the symbol found to be in pc_section, because
410 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
411 symbol - but find_pc_section won't return an absolute section and
412 hence the code below would skip over absolute symbols. We can
413 still take advantage of the call to find_pc_section, though - the
414 object file still must match. In case we have separate debug
415 files, search both the file and its separate debug file. There's
416 no telling which one will have the minimal symbols. */
418 objfile = pc_section->objfile;
419 if (objfile->separate_debug_objfile)
420 objfile = objfile->separate_debug_objfile;
422 for (; objfile != NULL; objfile = objfile->separate_debug_objfile_backlink)
424 /* If this objfile has a minimal symbol table, go search it using
425 a binary search. Note that a minimal symbol table always consists
426 of at least two symbols, a "real" symbol and the terminating
427 "null symbol". If there are no real symbols, then there is no
428 minimal symbol table at all. */
430 if (objfile->minimal_symbol_count > 0)
432 int best_zero_sized = -1;
434 msymbol = objfile->msymbols;
436 hi = objfile->minimal_symbol_count - 1;
438 /* This code assumes that the minimal symbols are sorted by
439 ascending address values. If the pc value is greater than or
440 equal to the first symbol's address, then some symbol in this
441 minimal symbol table is a suitable candidate for being the
442 "best" symbol. This includes the last real symbol, for cases
443 where the pc value is larger than any address in this vector.
445 By iterating until the address associated with the current
446 hi index (the endpoint of the test interval) is less than
447 or equal to the desired pc value, we accomplish two things:
448 (1) the case where the pc value is larger than any minimal
449 symbol address is trivially solved, (2) the address associated
450 with the hi index is always the one we want when the interation
451 terminates. In essence, we are iterating the test interval
452 down until the pc value is pushed out of it from the high end.
454 Warning: this code is trickier than it would appear at first. */
456 /* Should also require that pc is <= end of objfile. FIXME! */
457 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo]))
459 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc)
461 /* pc is still strictly less than highest address */
462 /* Note "new" will always be >= lo */
464 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) ||
475 /* If we have multiple symbols at the same address, we want
476 hi to point to the last one. That way we can find the
477 right symbol if it has an index greater than hi. */
478 while (hi < objfile->minimal_symbol_count - 1
479 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
480 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1])))
483 /* Skip various undesirable symbols. */
486 /* Skip any absolute symbols. This is apparently
487 what adb and dbx do, and is needed for the CM-5.
488 There are two known possible problems: (1) on
489 ELF, apparently end, edata, etc. are absolute.
490 Not sure ignoring them here is a big deal, but if
491 we want to use them, the fix would go in
492 elfread.c. (2) I think shared library entry
493 points on the NeXT are absolute. If we want
494 special handling for this it probably should be
495 triggered by a special mst_abs_or_lib or some
498 if (msymbol[hi].type == mst_abs)
504 /* If SECTION was specified, skip any symbol from
507 /* Some types of debug info, such as COFF,
508 don't fill the bfd_section member, so don't
509 throw away symbols on those platforms. */
510 && SYMBOL_BFD_SECTION (&msymbol[hi]) != NULL
511 && (!matching_bfd_sections
512 (SYMBOL_BFD_SECTION (&msymbol[hi]), section)))
518 /* If we are looking for a trampoline and this is a
519 text symbol, or the other way around, check the
520 preceeding symbol too. If they are otherwise
521 identical prefer that one. */
523 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
524 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
525 && (MSYMBOL_SIZE (&msymbol[hi])
526 == MSYMBOL_SIZE (&msymbol[hi - 1]))
527 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
528 == SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]))
529 && (SYMBOL_BFD_SECTION (&msymbol[hi])
530 == SYMBOL_BFD_SECTION (&msymbol[hi - 1])))
536 /* If the minimal symbol has a zero size, save it
537 but keep scanning backwards looking for one with
538 a non-zero size. A zero size may mean that the
539 symbol isn't an object or function (e.g. a
540 label), or it may just mean that the size was not
542 if (MSYMBOL_SIZE (&msymbol[hi]) == 0
543 && best_zero_sized == -1)
545 best_zero_sized = hi;
550 /* If we are past the end of the current symbol, try
551 the previous symbol if it has a larger overlapping
552 size. This happens on i686-pc-linux-gnu with glibc;
553 the nocancel variants of system calls are inside
554 the cancellable variants, but both have sizes. */
556 && MSYMBOL_SIZE (&msymbol[hi]) != 0
557 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
558 + MSYMBOL_SIZE (&msymbol[hi]))
559 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
560 + MSYMBOL_SIZE (&msymbol[hi - 1])))
566 /* Otherwise, this symbol must be as good as we're going
571 /* If HI has a zero size, and best_zero_sized is set,
572 then we had two or more zero-sized symbols; prefer
573 the first one we found (which may have a higher
574 address). Also, if we ran off the end, be sure
576 if (best_zero_sized != -1
577 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
578 hi = best_zero_sized;
580 /* If the minimal symbol has a non-zero size, and this
581 PC appears to be outside the symbol's contents, then
582 refuse to use this symbol. If we found a zero-sized
583 symbol with an address greater than this symbol's,
584 use that instead. We assume that if symbols have
585 specified sizes, they do not overlap. */
588 && MSYMBOL_SIZE (&msymbol[hi]) != 0
589 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
590 + MSYMBOL_SIZE (&msymbol[hi])))
592 if (best_zero_sized != -1)
593 hi = best_zero_sized;
595 /* Go on to the next object file. */
599 /* The minimal symbol indexed by hi now is the best one in this
600 objfile's minimal symbol table. See if it is the best one
604 && ((best_symbol == NULL) ||
605 (SYMBOL_VALUE_ADDRESS (best_symbol) <
606 SYMBOL_VALUE_ADDRESS (&msymbol[hi]))))
608 best_symbol = &msymbol[hi];
613 return (best_symbol);
616 struct minimal_symbol *
617 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, asection *section)
619 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
622 /* Backward compatibility: search through the minimal symbol table
623 for a matching PC (no section given) */
625 struct minimal_symbol *
626 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
628 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
629 force the section but that (well unless you're doing overlay
630 debugging) always returns NULL making the call somewhat useless. */
631 struct obj_section *section = find_pc_section (pc);
634 return lookup_minimal_symbol_by_pc_section (pc, section->the_bfd_section);
638 /* Return leading symbol character for a BFD. If BFD is NULL,
639 return the leading symbol character from the main objfile. */
641 static int get_symbol_leading_char (bfd *);
644 get_symbol_leading_char (bfd *abfd)
647 return bfd_get_symbol_leading_char (abfd);
648 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
649 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
653 /* Prepare to start collecting minimal symbols. Note that presetting
654 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
655 symbol to allocate the memory for the first bunch. */
658 init_minimal_symbol_collection (void)
662 msym_bunch_index = BUNCH_SIZE;
666 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
667 enum minimal_symbol_type ms_type,
668 struct objfile *objfile)
676 case mst_solib_trampoline:
677 section = SECT_OFF_TEXT (objfile);
681 section = SECT_OFF_DATA (objfile);
685 section = SECT_OFF_BSS (objfile);
691 prim_record_minimal_symbol_and_info (name, address, ms_type,
692 NULL, section, NULL, objfile);
695 /* Record a minimal symbol in the msym bunches. Returns the symbol
698 struct minimal_symbol *
699 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
700 enum minimal_symbol_type ms_type,
701 char *info, int section,
702 asection *bfd_section,
703 struct objfile *objfile)
705 struct msym_bunch *new;
706 struct minimal_symbol *msymbol;
708 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
709 the minimal symbols, because if there is also another symbol
710 at the same address (e.g. the first function of the file),
711 lookup_minimal_symbol_by_pc would have no way of getting the
713 if (ms_type == mst_file_text && name[0] == 'g'
714 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
715 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
718 /* It's safe to strip the leading char here once, since the name
719 is also stored stripped in the minimal symbol table. */
720 if (name[0] == get_symbol_leading_char (objfile->obfd))
723 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0)
726 if (msym_bunch_index == BUNCH_SIZE)
728 new = (struct msym_bunch *) xmalloc (sizeof (struct msym_bunch));
729 msym_bunch_index = 0;
730 new->next = msym_bunch;
733 msymbol = &msym_bunch->contents[msym_bunch_index];
734 SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown);
735 SYMBOL_LANGUAGE (msymbol) = language_auto;
736 SYMBOL_SET_NAMES (msymbol, (char *)name, strlen (name), objfile);
738 SYMBOL_VALUE_ADDRESS (msymbol) = address;
739 SYMBOL_SECTION (msymbol) = section;
740 SYMBOL_BFD_SECTION (msymbol) = bfd_section;
742 MSYMBOL_TYPE (msymbol) = ms_type;
743 /* FIXME: This info, if it remains, needs its own field. */
744 MSYMBOL_INFO (msymbol) = info; /* FIXME! */
745 MSYMBOL_SIZE (msymbol) = 0;
747 /* The hash pointers must be cleared! If they're not,
748 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
749 msymbol->hash_next = NULL;
750 msymbol->demangled_hash_next = NULL;
754 OBJSTAT (objfile, n_minsyms++);
758 /* Compare two minimal symbols by address and return a signed result based
759 on unsigned comparisons, so that we sort into unsigned numeric order.
760 Within groups with the same address, sort by name. */
763 compare_minimal_symbols (const void *fn1p, const void *fn2p)
765 const struct minimal_symbol *fn1;
766 const struct minimal_symbol *fn2;
768 fn1 = (const struct minimal_symbol *) fn1p;
769 fn2 = (const struct minimal_symbol *) fn2p;
771 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2))
773 return (-1); /* addr 1 is less than addr 2 */
775 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2))
777 return (1); /* addr 1 is greater than addr 2 */
780 /* addrs are equal: sort by name */
782 char *name1 = SYMBOL_LINKAGE_NAME (fn1);
783 char *name2 = SYMBOL_LINKAGE_NAME (fn2);
785 if (name1 && name2) /* both have names */
786 return strcmp (name1, name2);
788 return 1; /* fn1 has no name, so it is "less" */
789 else if (name1) /* fn2 has no name, so it is "less" */
792 return (0); /* neither has a name, so they're equal. */
796 /* Discard the currently collected minimal symbols, if any. If we wish
797 to save them for later use, we must have already copied them somewhere
798 else before calling this function.
800 FIXME: We could allocate the minimal symbol bunches on their own
801 obstack and then simply blow the obstack away when we are done with
802 it. Is it worth the extra trouble though? */
805 do_discard_minimal_symbols_cleanup (void *arg)
807 struct msym_bunch *next;
809 while (msym_bunch != NULL)
811 next = msym_bunch->next;
818 make_cleanup_discard_minimal_symbols (void)
820 return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
825 /* Compact duplicate entries out of a minimal symbol table by walking
826 through the table and compacting out entries with duplicate addresses
827 and matching names. Return the number of entries remaining.
829 On entry, the table resides between msymbol[0] and msymbol[mcount].
830 On exit, it resides between msymbol[0] and msymbol[result_count].
832 When files contain multiple sources of symbol information, it is
833 possible for the minimal symbol table to contain many duplicate entries.
834 As an example, SVR4 systems use ELF formatted object files, which
835 usually contain at least two different types of symbol tables (a
836 standard ELF one and a smaller dynamic linking table), as well as
837 DWARF debugging information for files compiled with -g.
839 Without compacting, the minimal symbol table for gdb itself contains
840 over a 1000 duplicates, about a third of the total table size. Aside
841 from the potential trap of not noticing that two successive entries
842 identify the same location, this duplication impacts the time required
843 to linearly scan the table, which is done in a number of places. So we
844 just do one linear scan here and toss out the duplicates.
846 Note that we are not concerned here about recovering the space that
847 is potentially freed up, because the strings themselves are allocated
848 on the objfile_obstack, and will get automatically freed when the symbol
849 table is freed. The caller can free up the unused minimal symbols at
850 the end of the compacted region if their allocation strategy allows it.
852 Also note we only go up to the next to last entry within the loop
853 and then copy the last entry explicitly after the loop terminates.
855 Since the different sources of information for each symbol may
856 have different levels of "completeness", we may have duplicates
857 that have one entry with type "mst_unknown" and the other with a
858 known type. So if the one we are leaving alone has type mst_unknown,
859 overwrite its type with the type from the one we are compacting out. */
862 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
863 struct objfile *objfile)
865 struct minimal_symbol *copyfrom;
866 struct minimal_symbol *copyto;
870 copyfrom = copyto = msymbol;
871 while (copyfrom < msymbol + mcount - 1)
873 if (SYMBOL_VALUE_ADDRESS (copyfrom)
874 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1))
875 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom),
876 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
878 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
880 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
885 *copyto++ = *copyfrom++;
887 *copyto++ = *copyfrom++;
888 mcount = copyto - msymbol;
893 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
894 after compacting or sorting the table since the entries move around
895 thus causing the internal minimal_symbol pointers to become jumbled. */
898 build_minimal_symbol_hash_tables (struct objfile *objfile)
901 struct minimal_symbol *msym;
903 /* Clear the hash tables. */
904 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
906 objfile->msymbol_hash[i] = 0;
907 objfile->msymbol_demangled_hash[i] = 0;
910 /* Now, (re)insert the actual entries. */
911 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols;
916 add_minsym_to_hash_table (msym, objfile->msymbol_hash);
918 msym->demangled_hash_next = 0;
919 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym))
920 add_minsym_to_demangled_hash_table (msym,
921 objfile->msymbol_demangled_hash);
925 /* Add the minimal symbols in the existing bunches to the objfile's official
926 minimal symbol table. In most cases there is no minimal symbol table yet
927 for this objfile, and the existing bunches are used to create one. Once
928 in a while (for shared libraries for example), we add symbols (e.g. common
929 symbols) to an existing objfile.
931 Because of the way minimal symbols are collected, we generally have no way
932 of knowing what source language applies to any particular minimal symbol.
933 Specifically, we have no way of knowing if the minimal symbol comes from a
934 C++ compilation unit or not. So for the sake of supporting cached
935 demangled C++ names, we have no choice but to try and demangle each new one
936 that comes in. If the demangling succeeds, then we assume it is a C++
937 symbol and set the symbol's language and demangled name fields
938 appropriately. Note that in order to avoid unnecessary demanglings, and
939 allocating obstack space that subsequently can't be freed for the demangled
940 names, we mark all newly added symbols with language_auto. After
941 compaction of the minimal symbols, we go back and scan the entire minimal
942 symbol table looking for these new symbols. For each new symbol we attempt
943 to demangle it, and if successful, record it as a language_cplus symbol
944 and cache the demangled form on the symbol obstack. Symbols which don't
945 demangle are marked as language_unknown symbols, which inhibits future
946 attempts to demangle them if we later add more minimal symbols. */
949 install_minimal_symbols (struct objfile *objfile)
953 struct msym_bunch *bunch;
954 struct minimal_symbol *msymbols;
959 /* Allocate enough space in the obstack, into which we will gather the
960 bunches of new and existing minimal symbols, sort them, and then
961 compact out the duplicate entries. Once we have a final table,
962 we will give back the excess space. */
964 alloc_count = msym_count + objfile->minimal_symbol_count + 1;
965 obstack_blank (&objfile->objfile_obstack,
966 alloc_count * sizeof (struct minimal_symbol));
967 msymbols = (struct minimal_symbol *)
968 obstack_base (&objfile->objfile_obstack);
970 /* Copy in the existing minimal symbols, if there are any. */
972 if (objfile->minimal_symbol_count)
973 memcpy ((char *) msymbols, (char *) objfile->msymbols,
974 objfile->minimal_symbol_count * sizeof (struct minimal_symbol));
976 /* Walk through the list of minimal symbol bunches, adding each symbol
977 to the new contiguous array of symbols. Note that we start with the
978 current, possibly partially filled bunch (thus we use the current
979 msym_bunch_index for the first bunch we copy over), and thereafter
980 each bunch is full. */
982 mcount = objfile->minimal_symbol_count;
984 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
986 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
987 msymbols[mcount] = bunch->contents[bindex];
988 msym_bunch_index = BUNCH_SIZE;
991 /* Sort the minimal symbols by address. */
993 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
994 compare_minimal_symbols);
996 /* Compact out any duplicates, and free up whatever space we are
999 mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1001 obstack_blank (&objfile->objfile_obstack,
1002 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1003 msymbols = (struct minimal_symbol *)
1004 obstack_finish (&objfile->objfile_obstack);
1006 /* We also terminate the minimal symbol table with a "null symbol",
1007 which is *not* included in the size of the table. This makes it
1008 easier to find the end of the table when we are handed a pointer
1009 to some symbol in the middle of it. Zero out the fields in the
1010 "null symbol" allocated at the end of the array. Note that the
1011 symbol count does *not* include this null symbol, which is why it
1012 is indexed by mcount and not mcount-1. */
1014 SYMBOL_LINKAGE_NAME (&msymbols[mcount]) = NULL;
1015 SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0;
1016 MSYMBOL_INFO (&msymbols[mcount]) = NULL;
1017 MSYMBOL_SIZE (&msymbols[mcount]) = 0;
1018 MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown;
1019 SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown);
1021 /* Attach the minimal symbol table to the specified objfile.
1022 The strings themselves are also located in the objfile_obstack
1025 objfile->minimal_symbol_count = mcount;
1026 objfile->msymbols = msymbols;
1028 /* Try to guess the appropriate C++ ABI by looking at the names
1029 of the minimal symbols in the table. */
1033 for (i = 0; i < mcount; i++)
1035 /* If a symbol's name starts with _Z and was successfully
1036 demangled, then we can assume we've found a GNU v3 symbol.
1037 For now we set the C++ ABI globally; if the user is
1038 mixing ABIs then the user will need to "set cp-abi"
1040 const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]);
1041 if (name[0] == '_' && name[1] == 'Z'
1042 && SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL)
1044 set_cp_abi_as_auto_default ("gnu-v3");
1050 /* Now build the hash tables; we can't do this incrementally
1051 at an earlier point since we weren't finished with the obstack
1052 yet. (And if the msymbol obstack gets moved, all the internal
1053 pointers to other msymbols need to be adjusted.) */
1054 build_minimal_symbol_hash_tables (objfile);
1058 /* Sort all the minimal symbols in OBJFILE. */
1061 msymbols_sort (struct objfile *objfile)
1063 qsort (objfile->msymbols, objfile->minimal_symbol_count,
1064 sizeof (struct minimal_symbol), compare_minimal_symbols);
1065 build_minimal_symbol_hash_tables (objfile);
1068 /* Check if PC is in a shared library trampoline code stub.
1069 Return minimal symbol for the trampoline entry or NULL if PC is not
1070 in a trampoline code stub. */
1072 struct minimal_symbol *
1073 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1075 struct obj_section *section = find_pc_section (pc);
1076 struct minimal_symbol *msymbol;
1078 if (section == NULL)
1080 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section->the_bfd_section,
1083 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
1088 /* If PC is in a shared library trampoline code stub, return the
1089 address of the `real' function belonging to the stub.
1090 Return 0 if PC is not in a trampoline code stub or if the real
1091 function is not found in the minimal symbol table.
1093 We may fail to find the right function if a function with the
1094 same name is defined in more than one shared library, but this
1095 is considered bad programming style. We could return 0 if we find
1096 a duplicate function in case this matters someday. */
1099 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1101 struct objfile *objfile;
1102 struct minimal_symbol *msymbol;
1103 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1105 if (tsymbol != NULL)
1107 ALL_MSYMBOLS (objfile, msymbol)
1109 if (MSYMBOL_TYPE (msymbol) == mst_text
1110 && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
1111 SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1112 return SYMBOL_VALUE_ADDRESS (msymbol);