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 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 #include "cp-support.h"
54 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
55 At the end, copy them all into one newly allocated location on an objfile's
58 #define BUNCH_SIZE 127
62 struct msym_bunch
*next
;
63 struct minimal_symbol contents
[BUNCH_SIZE
];
66 /* Bunch currently being filled up.
67 The next field points to chain of filled bunches. */
69 static struct msym_bunch
*msym_bunch
;
71 /* Number of slots filled in current bunch. */
73 static int msym_bunch_index
;
75 /* Total number of minimal symbols recorded so far for the objfile. */
77 static int msym_count
;
79 /* Compute a hash code based using the same criteria as `strcmp_iw'. */
82 msymbol_hash_iw (const char *string
)
84 unsigned int hash
= 0;
85 while (*string
&& *string
!= '(')
87 while (isspace (*string
))
89 if (*string
&& *string
!= '(')
91 hash
= hash
* 67 + *string
- 113;
98 /* Compute a hash code for a string. */
101 msymbol_hash (const char *string
)
103 unsigned int hash
= 0;
104 for (; *string
; ++string
)
105 hash
= hash
* 67 + *string
- 113;
109 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
111 add_minsym_to_hash_table (struct minimal_symbol
*sym
,
112 struct minimal_symbol
**table
)
114 if (sym
->hash_next
== NULL
)
117 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
118 sym
->hash_next
= table
[hash
];
123 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
126 add_minsym_to_demangled_hash_table (struct minimal_symbol
*sym
,
127 struct minimal_symbol
**table
)
129 if (sym
->demangled_hash_next
== NULL
)
132 = msymbol_hash_iw (SYMBOL_SEARCH_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
133 sym
->demangled_hash_next
= table
[hash
];
139 /* Return OBJFILE where minimal symbol SYM is defined. */
141 msymbol_objfile (struct minimal_symbol
*sym
)
143 struct objfile
*objf
;
144 struct minimal_symbol
*tsym
;
147 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
149 for (objf
= object_files
; objf
; objf
= objf
->next
)
150 for (tsym
= objf
->msymbol_hash
[hash
]; tsym
; tsym
= tsym
->hash_next
)
154 /* We should always be able to find the objfile ... */
155 internal_error (__FILE__
, __LINE__
, _("failed internal consistency check"));
159 /* Look through all the current minimal symbol tables and find the
160 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
161 the search to that objfile. If SFILE is non-NULL, the only file-scope
162 symbols considered will be from that source file (global symbols are
163 still preferred). Returns a pointer to the minimal symbol that
164 matches, or NULL if no match is found.
166 Note: One instance where there may be duplicate minimal symbols with
167 the same name is when the symbol tables for a shared library and the
168 symbol tables for an executable contain global symbols with the same
169 names (the dynamic linker deals with the duplication).
171 It's also possible to have minimal symbols with different mangled
172 names, but identical demangled names. For example, the GNU C++ v3
173 ABI requires the generation of two (or perhaps three) copies of
174 constructor functions --- "in-charge", "not-in-charge", and
175 "allocate" copies; destructors may be duplicated as well.
176 Obviously, there must be distinct mangled names for each of these,
177 but the demangled names are all the same: S::S or S::~S. */
179 struct minimal_symbol
*
180 lookup_minimal_symbol (const char *name
, const char *sfile
,
181 struct objfile
*objf
)
183 struct objfile
*objfile
;
184 struct minimal_symbol
*msymbol
;
185 struct minimal_symbol
*found_symbol
= NULL
;
186 struct minimal_symbol
*found_file_symbol
= NULL
;
187 struct minimal_symbol
*trampoline_symbol
= NULL
;
189 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
190 unsigned int dem_hash
= msymbol_hash_iw (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
192 int needtofreename
= 0;
193 const char *modified_name
;
197 char *p
= strrchr (sfile
, '/');
202 /* For C++, canonicalize the input name. */
203 modified_name
= name
;
204 if (current_language
->la_language
== language_cplus
)
206 char *cname
= cp_canonicalize_string (name
);
209 modified_name
= cname
;
214 for (objfile
= object_files
;
215 objfile
!= NULL
&& found_symbol
== NULL
;
216 objfile
= objfile
->next
)
218 if (objf
== NULL
|| objf
== objfile
219 || objf
== objfile
->separate_debug_objfile_backlink
)
221 /* Do two passes: the first over the ordinary hash table,
222 and the second over the demangled hash table. */
225 for (pass
= 1; pass
<= 2 && found_symbol
== NULL
; pass
++)
227 /* Select hash list according to pass. */
229 msymbol
= objfile
->msymbol_hash
[hash
];
231 msymbol
= objfile
->msymbol_demangled_hash
[dem_hash
];
233 while (msymbol
!= NULL
&& found_symbol
== NULL
)
239 match
= strcmp (SYMBOL_LINKAGE_NAME (msymbol
),
244 match
= SYMBOL_MATCHES_SEARCH_NAME (msymbol
,
250 switch (MSYMBOL_TYPE (msymbol
))
256 || strcmp (msymbol
->filename
, sfile
) == 0)
257 found_file_symbol
= msymbol
;
260 case mst_solib_trampoline
:
262 /* If a trampoline symbol is found, we prefer to
263 keep looking for the *real* symbol. If the
264 actual symbol is not found, then we'll use the
266 if (trampoline_symbol
== NULL
)
267 trampoline_symbol
= msymbol
;
272 found_symbol
= msymbol
;
277 /* Find the next symbol on the hash chain. */
279 msymbol
= msymbol
->hash_next
;
281 msymbol
= msymbol
->demangled_hash_next
;
288 xfree ((void *) modified_name
);
290 /* External symbols are best. */
294 /* File-local symbols are next best. */
295 if (found_file_symbol
)
296 return found_file_symbol
;
298 /* Symbols for shared library trampolines are next best. */
299 if (trampoline_symbol
)
300 return trampoline_symbol
;
305 /* Look through all the current minimal symbol tables and find the
306 first minimal symbol that matches NAME and has text type. If OBJF
307 is non-NULL, limit the search to that objfile. Returns a pointer
308 to the minimal symbol that matches, or NULL if no match is found.
310 This function only searches the mangled (linkage) names. */
312 struct minimal_symbol
*
313 lookup_minimal_symbol_text (const char *name
, struct objfile
*objf
)
315 struct objfile
*objfile
;
316 struct minimal_symbol
*msymbol
;
317 struct minimal_symbol
*found_symbol
= NULL
;
318 struct minimal_symbol
*found_file_symbol
= NULL
;
320 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
322 for (objfile
= object_files
;
323 objfile
!= NULL
&& found_symbol
== NULL
;
324 objfile
= objfile
->next
)
326 if (objf
== NULL
|| objf
== objfile
327 || objf
== objfile
->separate_debug_objfile_backlink
)
329 for (msymbol
= objfile
->msymbol_hash
[hash
];
330 msymbol
!= NULL
&& found_symbol
== NULL
;
331 msymbol
= msymbol
->hash_next
)
333 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
334 (MSYMBOL_TYPE (msymbol
) == mst_text
||
335 MSYMBOL_TYPE (msymbol
) == mst_file_text
))
337 switch (MSYMBOL_TYPE (msymbol
))
340 found_file_symbol
= msymbol
;
343 found_symbol
= msymbol
;
350 /* External symbols are best. */
354 /* File-local symbols are next best. */
355 if (found_file_symbol
)
356 return found_file_symbol
;
361 /* Look through all the current minimal symbol tables and find the
362 first minimal symbol that matches NAME and PC. If OBJF is non-NULL,
363 limit the search to that objfile. Returns a pointer to the minimal
364 symbol that matches, or NULL if no match is found. */
366 struct minimal_symbol
*
367 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc
, const char *name
,
368 struct objfile
*objf
)
370 struct objfile
*objfile
;
371 struct minimal_symbol
*msymbol
;
373 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
375 for (objfile
= object_files
;
377 objfile
= objfile
->next
)
379 if (objf
== NULL
|| objf
== objfile
380 || objf
== objfile
->separate_debug_objfile_backlink
)
382 for (msymbol
= objfile
->msymbol_hash
[hash
];
384 msymbol
= msymbol
->hash_next
)
386 if (SYMBOL_VALUE_ADDRESS (msymbol
) == pc
387 && strcmp (SYMBOL_LINKAGE_NAME (msymbol
), name
) == 0)
396 /* Look through all the current minimal symbol tables and find the
397 first minimal symbol that matches NAME and is a solib trampoline.
398 If OBJF is non-NULL, limit the search to that objfile. Returns a
399 pointer to the minimal symbol that matches, or NULL if no match is
402 This function only searches the mangled (linkage) names. */
404 struct minimal_symbol
*
405 lookup_minimal_symbol_solib_trampoline (const char *name
,
406 struct objfile
*objf
)
408 struct objfile
*objfile
;
409 struct minimal_symbol
*msymbol
;
410 struct minimal_symbol
*found_symbol
= NULL
;
412 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
414 for (objfile
= object_files
;
415 objfile
!= NULL
&& found_symbol
== NULL
;
416 objfile
= objfile
->next
)
418 if (objf
== NULL
|| objf
== objfile
419 || objf
== objfile
->separate_debug_objfile_backlink
)
421 for (msymbol
= objfile
->msymbol_hash
[hash
];
422 msymbol
!= NULL
&& found_symbol
== NULL
;
423 msymbol
= msymbol
->hash_next
)
425 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
426 MSYMBOL_TYPE (msymbol
) == mst_solib_trampoline
)
435 /* Search through the minimal symbol table for each objfile and find
436 the symbol whose address is the largest address that is still less
437 than or equal to PC, and matches SECTION (which is not NULL).
438 Returns a pointer to the minimal symbol if such a symbol is found,
439 or NULL if PC is not in a suitable range.
440 Note that we need to look through ALL the minimal symbol tables
441 before deciding on the symbol that comes closest to the specified PC.
442 This is because objfiles can overlap, for example objfile A has .text
443 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
446 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
447 there are text and trampoline symbols at the same address.
448 Otherwise prefer mst_text symbols. */
450 static struct minimal_symbol
*
451 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc
,
452 struct obj_section
*section
,
458 struct objfile
*objfile
;
459 struct minimal_symbol
*msymbol
;
460 struct minimal_symbol
*best_symbol
= NULL
;
461 enum minimal_symbol_type want_type
, other_type
;
463 want_type
= want_trampoline
? mst_solib_trampoline
: mst_text
;
464 other_type
= want_trampoline
? mst_text
: mst_solib_trampoline
;
466 /* We can not require the symbol found to be in section, because
467 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
468 symbol - but find_pc_section won't return an absolute section and
469 hence the code below would skip over absolute symbols. We can
470 still take advantage of the call to find_pc_section, though - the
471 object file still must match. In case we have separate debug
472 files, search both the file and its separate debug file. There's
473 no telling which one will have the minimal symbols. */
475 gdb_assert (section
!= NULL
);
477 for (objfile
= section
->objfile
;
479 objfile
= objfile_separate_debug_iterate (section
->objfile
, objfile
))
481 /* If this objfile has a minimal symbol table, go search it using
482 a binary search. Note that a minimal symbol table always consists
483 of at least two symbols, a "real" symbol and the terminating
484 "null symbol". If there are no real symbols, then there is no
485 minimal symbol table at all. */
487 if (objfile
->minimal_symbol_count
> 0)
489 int best_zero_sized
= -1;
491 msymbol
= objfile
->msymbols
;
493 hi
= objfile
->minimal_symbol_count
- 1;
495 /* This code assumes that the minimal symbols are sorted by
496 ascending address values. If the pc value is greater than or
497 equal to the first symbol's address, then some symbol in this
498 minimal symbol table is a suitable candidate for being the
499 "best" symbol. This includes the last real symbol, for cases
500 where the pc value is larger than any address in this vector.
502 By iterating until the address associated with the current
503 hi index (the endpoint of the test interval) is less than
504 or equal to the desired pc value, we accomplish two things:
505 (1) the case where the pc value is larger than any minimal
506 symbol address is trivially solved, (2) the address associated
507 with the hi index is always the one we want when the interation
508 terminates. In essence, we are iterating the test interval
509 down until the pc value is pushed out of it from the high end.
511 Warning: this code is trickier than it would appear at first. */
513 /* Should also require that pc is <= end of objfile. FIXME! */
514 if (pc
>= SYMBOL_VALUE_ADDRESS (&msymbol
[lo
]))
516 while (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
]) > pc
)
518 /* pc is still strictly less than highest address */
519 /* Note "new" will always be >= lo */
521 if ((SYMBOL_VALUE_ADDRESS (&msymbol
[new]) >= pc
) ||
532 /* If we have multiple symbols at the same address, we want
533 hi to point to the last one. That way we can find the
534 right symbol if it has an index greater than hi. */
535 while (hi
< objfile
->minimal_symbol_count
- 1
536 && (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
537 == SYMBOL_VALUE_ADDRESS (&msymbol
[hi
+ 1])))
540 /* Skip various undesirable symbols. */
543 /* Skip any absolute symbols. This is apparently
544 what adb and dbx do, and is needed for the CM-5.
545 There are two known possible problems: (1) on
546 ELF, apparently end, edata, etc. are absolute.
547 Not sure ignoring them here is a big deal, but if
548 we want to use them, the fix would go in
549 elfread.c. (2) I think shared library entry
550 points on the NeXT are absolute. If we want
551 special handling for this it probably should be
552 triggered by a special mst_abs_or_lib or some
555 if (MSYMBOL_TYPE (&msymbol
[hi
]) == mst_abs
)
561 /* If SECTION was specified, skip any symbol from
564 /* Some types of debug info, such as COFF,
565 don't fill the bfd_section member, so don't
566 throw away symbols on those platforms. */
567 && SYMBOL_OBJ_SECTION (&msymbol
[hi
]) != NULL
568 && (!matching_obj_sections
569 (SYMBOL_OBJ_SECTION (&msymbol
[hi
]), section
)))
575 /* If we are looking for a trampoline and this is a
576 text symbol, or the other way around, check the
577 preceeding symbol too. If they are otherwise
578 identical prefer that one. */
580 && MSYMBOL_TYPE (&msymbol
[hi
]) == other_type
581 && MSYMBOL_TYPE (&msymbol
[hi
- 1]) == want_type
582 && (MSYMBOL_SIZE (&msymbol
[hi
])
583 == MSYMBOL_SIZE (&msymbol
[hi
- 1]))
584 && (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
585 == SYMBOL_VALUE_ADDRESS (&msymbol
[hi
- 1]))
586 && (SYMBOL_OBJ_SECTION (&msymbol
[hi
])
587 == SYMBOL_OBJ_SECTION (&msymbol
[hi
- 1])))
593 /* If the minimal symbol has a zero size, save it
594 but keep scanning backwards looking for one with
595 a non-zero size. A zero size may mean that the
596 symbol isn't an object or function (e.g. a
597 label), or it may just mean that the size was not
599 if (MSYMBOL_SIZE (&msymbol
[hi
]) == 0
600 && best_zero_sized
== -1)
602 best_zero_sized
= hi
;
607 /* If we are past the end of the current symbol, try
608 the previous symbol if it has a larger overlapping
609 size. This happens on i686-pc-linux-gnu with glibc;
610 the nocancel variants of system calls are inside
611 the cancellable variants, but both have sizes. */
613 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
614 && pc
>= (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
615 + MSYMBOL_SIZE (&msymbol
[hi
]))
616 && pc
< (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
- 1])
617 + MSYMBOL_SIZE (&msymbol
[hi
- 1])))
623 /* Otherwise, this symbol must be as good as we're going
628 /* If HI has a zero size, and best_zero_sized is set,
629 then we had two or more zero-sized symbols; prefer
630 the first one we found (which may have a higher
631 address). Also, if we ran off the end, be sure
633 if (best_zero_sized
!= -1
634 && (hi
< 0 || MSYMBOL_SIZE (&msymbol
[hi
]) == 0))
635 hi
= best_zero_sized
;
637 /* If the minimal symbol has a non-zero size, and this
638 PC appears to be outside the symbol's contents, then
639 refuse to use this symbol. If we found a zero-sized
640 symbol with an address greater than this symbol's,
641 use that instead. We assume that if symbols have
642 specified sizes, they do not overlap. */
645 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
646 && pc
>= (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
647 + MSYMBOL_SIZE (&msymbol
[hi
])))
649 if (best_zero_sized
!= -1)
650 hi
= best_zero_sized
;
652 /* Go on to the next object file. */
656 /* The minimal symbol indexed by hi now is the best one in this
657 objfile's minimal symbol table. See if it is the best one
661 && ((best_symbol
== NULL
) ||
662 (SYMBOL_VALUE_ADDRESS (best_symbol
) <
663 SYMBOL_VALUE_ADDRESS (&msymbol
[hi
]))))
665 best_symbol
= &msymbol
[hi
];
670 return (best_symbol
);
673 struct minimal_symbol
*
674 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc
, struct obj_section
*section
)
678 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
679 force the section but that (well unless you're doing overlay
680 debugging) always returns NULL making the call somewhat useless. */
681 section
= find_pc_section (pc
);
685 return lookup_minimal_symbol_by_pc_section_1 (pc
, section
, 0);
688 /* Backward compatibility: search through the minimal symbol table
689 for a matching PC (no section given) */
691 struct minimal_symbol
*
692 lookup_minimal_symbol_by_pc (CORE_ADDR pc
)
694 return lookup_minimal_symbol_by_pc_section (pc
, NULL
);
698 /* Return leading symbol character for a BFD. If BFD is NULL,
699 return the leading symbol character from the main objfile. */
701 static int get_symbol_leading_char (bfd
*);
704 get_symbol_leading_char (bfd
*abfd
)
707 return bfd_get_symbol_leading_char (abfd
);
708 if (symfile_objfile
!= NULL
&& symfile_objfile
->obfd
!= NULL
)
709 return bfd_get_symbol_leading_char (symfile_objfile
->obfd
);
713 /* Prepare to start collecting minimal symbols. Note that presetting
714 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
715 symbol to allocate the memory for the first bunch. */
718 init_minimal_symbol_collection (void)
722 msym_bunch_index
= BUNCH_SIZE
;
726 prim_record_minimal_symbol (const char *name
, CORE_ADDR address
,
727 enum minimal_symbol_type ms_type
,
728 struct objfile
*objfile
)
736 case mst_solib_trampoline
:
737 section
= SECT_OFF_TEXT (objfile
);
741 section
= SECT_OFF_DATA (objfile
);
745 section
= SECT_OFF_BSS (objfile
);
751 prim_record_minimal_symbol_and_info (name
, address
, ms_type
,
752 section
, NULL
, objfile
);
755 /* Record a minimal symbol in the msym bunches. Returns the symbol
758 struct minimal_symbol
*
759 prim_record_minimal_symbol_full (const char *name
, int name_len
, int copy_name
,
761 enum minimal_symbol_type ms_type
,
763 asection
*bfd_section
,
764 struct objfile
*objfile
)
766 struct obj_section
*obj_section
;
767 struct msym_bunch
*new;
768 struct minimal_symbol
*msymbol
;
770 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
771 the minimal symbols, because if there is also another symbol
772 at the same address (e.g. the first function of the file),
773 lookup_minimal_symbol_by_pc would have no way of getting the
775 if (ms_type
== mst_file_text
&& name
[0] == 'g'
776 && (strcmp (name
, GCC_COMPILED_FLAG_SYMBOL
) == 0
777 || strcmp (name
, GCC2_COMPILED_FLAG_SYMBOL
) == 0))
780 /* It's safe to strip the leading char here once, since the name
781 is also stored stripped in the minimal symbol table. */
782 if (name
[0] == get_symbol_leading_char (objfile
->obfd
))
788 if (ms_type
== mst_file_text
&& strncmp (name
, "__gnu_compiled", 14) == 0)
791 if (msym_bunch_index
== BUNCH_SIZE
)
793 new = XCALLOC (1, struct msym_bunch
);
794 msym_bunch_index
= 0;
795 new->next
= msym_bunch
;
798 msymbol
= &msym_bunch
->contents
[msym_bunch_index
];
799 SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol
, language_unknown
);
800 SYMBOL_LANGUAGE (msymbol
) = language_auto
;
801 SYMBOL_SET_NAMES (msymbol
, name
, name_len
, copy_name
, objfile
);
803 SYMBOL_VALUE_ADDRESS (msymbol
) = address
;
804 SYMBOL_SECTION (msymbol
) = section
;
805 SYMBOL_OBJ_SECTION (msymbol
) = NULL
;
807 /* Find obj_section corresponding to bfd_section. */
809 ALL_OBJFILE_OSECTIONS (objfile
, obj_section
)
811 if (obj_section
->the_bfd_section
== bfd_section
)
813 SYMBOL_OBJ_SECTION (msymbol
) = obj_section
;
818 MSYMBOL_TYPE (msymbol
) = ms_type
;
819 MSYMBOL_TARGET_FLAG_1 (msymbol
) = 0;
820 MSYMBOL_TARGET_FLAG_2 (msymbol
) = 0;
821 MSYMBOL_SIZE (msymbol
) = 0;
823 /* The hash pointers must be cleared! If they're not,
824 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
825 msymbol
->hash_next
= NULL
;
826 msymbol
->demangled_hash_next
= NULL
;
830 OBJSTAT (objfile
, n_minsyms
++);
834 /* Record a minimal symbol in the msym bunches. Returns the symbol
837 struct minimal_symbol
*
838 prim_record_minimal_symbol_and_info (const char *name
, CORE_ADDR address
,
839 enum minimal_symbol_type ms_type
,
841 asection
*bfd_section
,
842 struct objfile
*objfile
)
844 return prim_record_minimal_symbol_full (name
, strlen (name
), 1,
845 address
, ms_type
, section
,
846 bfd_section
, objfile
);
849 /* Compare two minimal symbols by address and return a signed result based
850 on unsigned comparisons, so that we sort into unsigned numeric order.
851 Within groups with the same address, sort by name. */
854 compare_minimal_symbols (const void *fn1p
, const void *fn2p
)
856 const struct minimal_symbol
*fn1
;
857 const struct minimal_symbol
*fn2
;
859 fn1
= (const struct minimal_symbol
*) fn1p
;
860 fn2
= (const struct minimal_symbol
*) fn2p
;
862 if (SYMBOL_VALUE_ADDRESS (fn1
) < SYMBOL_VALUE_ADDRESS (fn2
))
864 return (-1); /* addr 1 is less than addr 2 */
866 else if (SYMBOL_VALUE_ADDRESS (fn1
) > SYMBOL_VALUE_ADDRESS (fn2
))
868 return (1); /* addr 1 is greater than addr 2 */
871 /* addrs are equal: sort by name */
873 char *name1
= SYMBOL_LINKAGE_NAME (fn1
);
874 char *name2
= SYMBOL_LINKAGE_NAME (fn2
);
876 if (name1
&& name2
) /* both have names */
877 return strcmp (name1
, name2
);
879 return 1; /* fn1 has no name, so it is "less" */
880 else if (name1
) /* fn2 has no name, so it is "less" */
883 return (0); /* neither has a name, so they're equal. */
887 /* Discard the currently collected minimal symbols, if any. If we wish
888 to save them for later use, we must have already copied them somewhere
889 else before calling this function.
891 FIXME: We could allocate the minimal symbol bunches on their own
892 obstack and then simply blow the obstack away when we are done with
893 it. Is it worth the extra trouble though? */
896 do_discard_minimal_symbols_cleanup (void *arg
)
898 struct msym_bunch
*next
;
900 while (msym_bunch
!= NULL
)
902 next
= msym_bunch
->next
;
909 make_cleanup_discard_minimal_symbols (void)
911 return make_cleanup (do_discard_minimal_symbols_cleanup
, 0);
916 /* Compact duplicate entries out of a minimal symbol table by walking
917 through the table and compacting out entries with duplicate addresses
918 and matching names. Return the number of entries remaining.
920 On entry, the table resides between msymbol[0] and msymbol[mcount].
921 On exit, it resides between msymbol[0] and msymbol[result_count].
923 When files contain multiple sources of symbol information, it is
924 possible for the minimal symbol table to contain many duplicate entries.
925 As an example, SVR4 systems use ELF formatted object files, which
926 usually contain at least two different types of symbol tables (a
927 standard ELF one and a smaller dynamic linking table), as well as
928 DWARF debugging information for files compiled with -g.
930 Without compacting, the minimal symbol table for gdb itself contains
931 over a 1000 duplicates, about a third of the total table size. Aside
932 from the potential trap of not noticing that two successive entries
933 identify the same location, this duplication impacts the time required
934 to linearly scan the table, which is done in a number of places. So we
935 just do one linear scan here and toss out the duplicates.
937 Note that we are not concerned here about recovering the space that
938 is potentially freed up, because the strings themselves are allocated
939 on the objfile_obstack, and will get automatically freed when the symbol
940 table is freed. The caller can free up the unused minimal symbols at
941 the end of the compacted region if their allocation strategy allows it.
943 Also note we only go up to the next to last entry within the loop
944 and then copy the last entry explicitly after the loop terminates.
946 Since the different sources of information for each symbol may
947 have different levels of "completeness", we may have duplicates
948 that have one entry with type "mst_unknown" and the other with a
949 known type. So if the one we are leaving alone has type mst_unknown,
950 overwrite its type with the type from the one we are compacting out. */
953 compact_minimal_symbols (struct minimal_symbol
*msymbol
, int mcount
,
954 struct objfile
*objfile
)
956 struct minimal_symbol
*copyfrom
;
957 struct minimal_symbol
*copyto
;
961 copyfrom
= copyto
= msymbol
;
962 while (copyfrom
< msymbol
+ mcount
- 1)
964 if (SYMBOL_VALUE_ADDRESS (copyfrom
)
965 == SYMBOL_VALUE_ADDRESS ((copyfrom
+ 1))
966 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom
),
967 SYMBOL_LINKAGE_NAME ((copyfrom
+ 1))) == 0)
969 if (MSYMBOL_TYPE ((copyfrom
+ 1)) == mst_unknown
)
971 MSYMBOL_TYPE ((copyfrom
+ 1)) = MSYMBOL_TYPE (copyfrom
);
976 *copyto
++ = *copyfrom
++;
978 *copyto
++ = *copyfrom
++;
979 mcount
= copyto
- msymbol
;
984 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
985 after compacting or sorting the table since the entries move around
986 thus causing the internal minimal_symbol pointers to become jumbled. */
989 build_minimal_symbol_hash_tables (struct objfile
*objfile
)
992 struct minimal_symbol
*msym
;
994 /* Clear the hash tables. */
995 for (i
= 0; i
< MINIMAL_SYMBOL_HASH_SIZE
; i
++)
997 objfile
->msymbol_hash
[i
] = 0;
998 objfile
->msymbol_demangled_hash
[i
] = 0;
1001 /* Now, (re)insert the actual entries. */
1002 for (i
= objfile
->minimal_symbol_count
, msym
= objfile
->msymbols
;
1006 msym
->hash_next
= 0;
1007 add_minsym_to_hash_table (msym
, objfile
->msymbol_hash
);
1009 msym
->demangled_hash_next
= 0;
1010 if (SYMBOL_SEARCH_NAME (msym
) != SYMBOL_LINKAGE_NAME (msym
))
1011 add_minsym_to_demangled_hash_table (msym
,
1012 objfile
->msymbol_demangled_hash
);
1016 /* Add the minimal symbols in the existing bunches to the objfile's official
1017 minimal symbol table. In most cases there is no minimal symbol table yet
1018 for this objfile, and the existing bunches are used to create one. Once
1019 in a while (for shared libraries for example), we add symbols (e.g. common
1020 symbols) to an existing objfile.
1022 Because of the way minimal symbols are collected, we generally have no way
1023 of knowing what source language applies to any particular minimal symbol.
1024 Specifically, we have no way of knowing if the minimal symbol comes from a
1025 C++ compilation unit or not. So for the sake of supporting cached
1026 demangled C++ names, we have no choice but to try and demangle each new one
1027 that comes in. If the demangling succeeds, then we assume it is a C++
1028 symbol and set the symbol's language and demangled name fields
1029 appropriately. Note that in order to avoid unnecessary demanglings, and
1030 allocating obstack space that subsequently can't be freed for the demangled
1031 names, we mark all newly added symbols with language_auto. After
1032 compaction of the minimal symbols, we go back and scan the entire minimal
1033 symbol table looking for these new symbols. For each new symbol we attempt
1034 to demangle it, and if successful, record it as a language_cplus symbol
1035 and cache the demangled form on the symbol obstack. Symbols which don't
1036 demangle are marked as language_unknown symbols, which inhibits future
1037 attempts to demangle them if we later add more minimal symbols. */
1040 install_minimal_symbols (struct objfile
*objfile
)
1044 struct msym_bunch
*bunch
;
1045 struct minimal_symbol
*msymbols
;
1050 /* Allocate enough space in the obstack, into which we will gather the
1051 bunches of new and existing minimal symbols, sort them, and then
1052 compact out the duplicate entries. Once we have a final table,
1053 we will give back the excess space. */
1055 alloc_count
= msym_count
+ objfile
->minimal_symbol_count
+ 1;
1056 obstack_blank (&objfile
->objfile_obstack
,
1057 alloc_count
* sizeof (struct minimal_symbol
));
1058 msymbols
= (struct minimal_symbol
*)
1059 obstack_base (&objfile
->objfile_obstack
);
1061 /* Copy in the existing minimal symbols, if there are any. */
1063 if (objfile
->minimal_symbol_count
)
1064 memcpy ((char *) msymbols
, (char *) objfile
->msymbols
,
1065 objfile
->minimal_symbol_count
* sizeof (struct minimal_symbol
));
1067 /* Walk through the list of minimal symbol bunches, adding each symbol
1068 to the new contiguous array of symbols. Note that we start with the
1069 current, possibly partially filled bunch (thus we use the current
1070 msym_bunch_index for the first bunch we copy over), and thereafter
1071 each bunch is full. */
1073 mcount
= objfile
->minimal_symbol_count
;
1075 for (bunch
= msym_bunch
; bunch
!= NULL
; bunch
= bunch
->next
)
1077 for (bindex
= 0; bindex
< msym_bunch_index
; bindex
++, mcount
++)
1078 msymbols
[mcount
] = bunch
->contents
[bindex
];
1079 msym_bunch_index
= BUNCH_SIZE
;
1082 /* Sort the minimal symbols by address. */
1084 qsort (msymbols
, mcount
, sizeof (struct minimal_symbol
),
1085 compare_minimal_symbols
);
1087 /* Compact out any duplicates, and free up whatever space we are
1090 mcount
= compact_minimal_symbols (msymbols
, mcount
, objfile
);
1092 obstack_blank (&objfile
->objfile_obstack
,
1093 (mcount
+ 1 - alloc_count
) * sizeof (struct minimal_symbol
));
1094 msymbols
= (struct minimal_symbol
*)
1095 obstack_finish (&objfile
->objfile_obstack
);
1097 /* We also terminate the minimal symbol table with a "null symbol",
1098 which is *not* included in the size of the table. This makes it
1099 easier to find the end of the table when we are handed a pointer
1100 to some symbol in the middle of it. Zero out the fields in the
1101 "null symbol" allocated at the end of the array. Note that the
1102 symbol count does *not* include this null symbol, which is why it
1103 is indexed by mcount and not mcount-1. */
1105 SYMBOL_LINKAGE_NAME (&msymbols
[mcount
]) = NULL
;
1106 SYMBOL_VALUE_ADDRESS (&msymbols
[mcount
]) = 0;
1107 MSYMBOL_TARGET_FLAG_1 (&msymbols
[mcount
]) = 0;
1108 MSYMBOL_TARGET_FLAG_2 (&msymbols
[mcount
]) = 0;
1109 MSYMBOL_SIZE (&msymbols
[mcount
]) = 0;
1110 MSYMBOL_TYPE (&msymbols
[mcount
]) = mst_unknown
;
1111 SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols
[mcount
], language_unknown
);
1113 /* Attach the minimal symbol table to the specified objfile.
1114 The strings themselves are also located in the objfile_obstack
1117 objfile
->minimal_symbol_count
= mcount
;
1118 objfile
->msymbols
= msymbols
;
1120 /* Try to guess the appropriate C++ ABI by looking at the names
1121 of the minimal symbols in the table. */
1125 for (i
= 0; i
< mcount
; i
++)
1127 /* If a symbol's name starts with _Z and was successfully
1128 demangled, then we can assume we've found a GNU v3 symbol.
1129 For now we set the C++ ABI globally; if the user is
1130 mixing ABIs then the user will need to "set cp-abi"
1132 const char *name
= SYMBOL_LINKAGE_NAME (&objfile
->msymbols
[i
]);
1133 if (name
[0] == '_' && name
[1] == 'Z'
1134 && SYMBOL_DEMANGLED_NAME (&objfile
->msymbols
[i
]) != NULL
)
1136 set_cp_abi_as_auto_default ("gnu-v3");
1142 /* Now build the hash tables; we can't do this incrementally
1143 at an earlier point since we weren't finished with the obstack
1144 yet. (And if the msymbol obstack gets moved, all the internal
1145 pointers to other msymbols need to be adjusted.) */
1146 build_minimal_symbol_hash_tables (objfile
);
1150 /* Sort all the minimal symbols in OBJFILE. */
1153 msymbols_sort (struct objfile
*objfile
)
1155 qsort (objfile
->msymbols
, objfile
->minimal_symbol_count
,
1156 sizeof (struct minimal_symbol
), compare_minimal_symbols
);
1157 build_minimal_symbol_hash_tables (objfile
);
1160 /* Check if PC is in a shared library trampoline code stub.
1161 Return minimal symbol for the trampoline entry or NULL if PC is not
1162 in a trampoline code stub. */
1164 struct minimal_symbol
*
1165 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc
)
1167 struct obj_section
*section
= find_pc_section (pc
);
1168 struct minimal_symbol
*msymbol
;
1170 if (section
== NULL
)
1172 msymbol
= lookup_minimal_symbol_by_pc_section_1 (pc
, section
, 1);
1174 if (msymbol
!= NULL
&& MSYMBOL_TYPE (msymbol
) == mst_solib_trampoline
)
1179 /* If PC is in a shared library trampoline code stub, return the
1180 address of the `real' function belonging to the stub.
1181 Return 0 if PC is not in a trampoline code stub or if the real
1182 function is not found in the minimal symbol table.
1184 We may fail to find the right function if a function with the
1185 same name is defined in more than one shared library, but this
1186 is considered bad programming style. We could return 0 if we find
1187 a duplicate function in case this matters someday. */
1190 find_solib_trampoline_target (struct frame_info
*frame
, CORE_ADDR pc
)
1192 struct objfile
*objfile
;
1193 struct minimal_symbol
*msymbol
;
1194 struct minimal_symbol
*tsymbol
= lookup_solib_trampoline_symbol_by_pc (pc
);
1196 if (tsymbol
!= NULL
)
1198 ALL_MSYMBOLS (objfile
, msymbol
)
1200 if (MSYMBOL_TYPE (msymbol
) == mst_text
1201 && strcmp (SYMBOL_LINKAGE_NAME (msymbol
),
1202 SYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1203 return SYMBOL_VALUE_ADDRESS (msymbol
);
1205 /* Also handle minimal symbols pointing to function descriptors. */
1206 if (MSYMBOL_TYPE (msymbol
) == mst_data
1207 && strcmp (SYMBOL_LINKAGE_NAME (msymbol
),
1208 SYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1211 func
= gdbarch_convert_from_func_ptr_addr
1212 (get_objfile_arch (objfile
),
1213 SYMBOL_VALUE_ADDRESS (msymbol
),
1216 /* Ignore data symbols that are not function descriptors. */
1217 if (func
!= SYMBOL_VALUE_ADDRESS (msymbol
))