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"
52 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
53 At the end, copy them all into one newly allocated location on an objfile's
56 #define BUNCH_SIZE 127
60 struct msym_bunch
*next
;
61 struct minimal_symbol contents
[BUNCH_SIZE
];
64 /* Bunch currently being filled up.
65 The next field points to chain of filled bunches. */
67 static struct msym_bunch
*msym_bunch
;
69 /* Number of slots filled in current bunch. */
71 static int msym_bunch_index
;
73 /* Total number of minimal symbols recorded so far for the objfile. */
75 static int msym_count
;
77 /* Compute a hash code based using the same criteria as `strcmp_iw'. */
80 msymbol_hash_iw (const char *string
)
82 unsigned int hash
= 0;
83 while (*string
&& *string
!= '(')
85 while (isspace (*string
))
87 if (*string
&& *string
!= '(')
89 hash
= hash
* 67 + *string
- 113;
96 /* Compute a hash code for a string. */
99 msymbol_hash (const char *string
)
101 unsigned int hash
= 0;
102 for (; *string
; ++string
)
103 hash
= hash
* 67 + *string
- 113;
107 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
109 add_minsym_to_hash_table (struct minimal_symbol
*sym
,
110 struct minimal_symbol
**table
)
112 if (sym
->hash_next
== NULL
)
115 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
116 sym
->hash_next
= table
[hash
];
121 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
124 add_minsym_to_demangled_hash_table (struct minimal_symbol
*sym
,
125 struct minimal_symbol
**table
)
127 if (sym
->demangled_hash_next
== NULL
)
130 = msymbol_hash_iw (SYMBOL_SEARCH_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
131 sym
->demangled_hash_next
= table
[hash
];
137 /* Return OBJFILE where minimal symbol SYM is defined. */
139 msymbol_objfile (struct minimal_symbol
*sym
)
141 struct objfile
*objf
;
142 struct minimal_symbol
*tsym
;
145 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
147 for (objf
= object_files
; objf
; objf
= objf
->next
)
148 for (tsym
= objf
->msymbol_hash
[hash
]; tsym
; tsym
= tsym
->hash_next
)
152 /* We should always be able to find the objfile ... */
153 internal_error (__FILE__
, __LINE__
, _("failed internal consistency check"));
157 /* Look through all the current minimal symbol tables and find the
158 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
159 the search to that objfile. If SFILE is non-NULL, the only file-scope
160 symbols considered will be from that source file (global symbols are
161 still preferred). Returns a pointer to the minimal symbol that
162 matches, or NULL if no match is found.
164 Note: One instance where there may be duplicate minimal symbols with
165 the same name is when the symbol tables for a shared library and the
166 symbol tables for an executable contain global symbols with the same
167 names (the dynamic linker deals with the duplication).
169 It's also possible to have minimal symbols with different mangled
170 names, but identical demangled names. For example, the GNU C++ v3
171 ABI requires the generation of two (or perhaps three) copies of
172 constructor functions --- "in-charge", "not-in-charge", and
173 "allocate" copies; destructors may be duplicated as well.
174 Obviously, there must be distinct mangled names for each of these,
175 but the demangled names are all the same: S::S or S::~S. */
177 struct minimal_symbol
*
178 lookup_minimal_symbol (const char *name
, const char *sfile
,
179 struct objfile
*objf
)
181 struct objfile
*objfile
;
182 struct minimal_symbol
*msymbol
;
183 struct minimal_symbol
*found_symbol
= NULL
;
184 struct minimal_symbol
*found_file_symbol
= NULL
;
185 struct minimal_symbol
*trampoline_symbol
= NULL
;
187 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
188 unsigned int dem_hash
= msymbol_hash_iw (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
192 char *p
= strrchr (sfile
, '/');
197 for (objfile
= object_files
;
198 objfile
!= NULL
&& found_symbol
== NULL
;
199 objfile
= objfile
->next
)
201 if (objf
== NULL
|| objf
== objfile
202 || objf
->separate_debug_objfile
== objfile
)
204 /* Do two passes: the first over the ordinary hash table,
205 and the second over the demangled hash table. */
208 for (pass
= 1; pass
<= 2 && found_symbol
== NULL
; pass
++)
210 /* Select hash list according to pass. */
212 msymbol
= objfile
->msymbol_hash
[hash
];
214 msymbol
= objfile
->msymbol_demangled_hash
[dem_hash
];
216 while (msymbol
!= NULL
&& found_symbol
== NULL
)
221 match
= strcmp (SYMBOL_LINKAGE_NAME (msymbol
), name
) == 0;
223 match
= SYMBOL_MATCHES_SEARCH_NAME (msymbol
, name
);
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 PC. If OBJF is non-NULL,
335 limit the search to that objfile. Returns a pointer to the minimal
336 symbol that matches, or NULL if no match is found. */
338 struct minimal_symbol
*
339 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc
, const char *name
,
340 struct objfile
*objf
)
342 struct objfile
*objfile
;
343 struct minimal_symbol
*msymbol
;
345 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
347 for (objfile
= object_files
;
349 objfile
= objfile
->next
)
351 if (objf
== NULL
|| objf
== objfile
352 || objf
->separate_debug_objfile
== objfile
)
354 for (msymbol
= objfile
->msymbol_hash
[hash
];
356 msymbol
= msymbol
->hash_next
)
358 if (SYMBOL_VALUE_ADDRESS (msymbol
) == pc
359 && strcmp (SYMBOL_LINKAGE_NAME (msymbol
), name
) == 0)
368 /* Look through all the current minimal symbol tables and find the
369 first minimal symbol that matches NAME and is a solib trampoline.
370 If OBJF is non-NULL, limit the search to that objfile. Returns a
371 pointer to the minimal symbol that matches, or NULL if no match is
374 This function only searches the mangled (linkage) names. */
376 struct minimal_symbol
*
377 lookup_minimal_symbol_solib_trampoline (const char *name
,
378 struct objfile
*objf
)
380 struct objfile
*objfile
;
381 struct minimal_symbol
*msymbol
;
382 struct minimal_symbol
*found_symbol
= NULL
;
384 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
386 for (objfile
= object_files
;
387 objfile
!= NULL
&& found_symbol
== NULL
;
388 objfile
= objfile
->next
)
390 if (objf
== NULL
|| objf
== objfile
391 || objf
->separate_debug_objfile
== objfile
)
393 for (msymbol
= objfile
->msymbol_hash
[hash
];
394 msymbol
!= NULL
&& found_symbol
== NULL
;
395 msymbol
= msymbol
->hash_next
)
397 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
398 MSYMBOL_TYPE (msymbol
) == mst_solib_trampoline
)
407 /* Search through the minimal symbol table for each objfile and find
408 the symbol whose address is the largest address that is still less
409 than or equal to PC, and matches SECTION (if non-NULL). Returns a
410 pointer to the minimal symbol if such a symbol is found, or NULL if
411 PC is not in a suitable range. Note that we need to look through
412 ALL the minimal symbol tables before deciding on the symbol that
413 comes closest to the specified PC. This is because objfiles can
414 overlap, for example objfile A has .text at 0x100 and .data at
415 0x40000 and objfile B has .text at 0x234 and .data at 0x40048.
417 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
418 there are text and trampoline symbols at the same address.
419 Otherwise prefer mst_text symbols. */
421 static struct minimal_symbol
*
422 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc
, asection
*section
,
428 struct objfile
*objfile
;
429 struct minimal_symbol
*msymbol
;
430 struct minimal_symbol
*best_symbol
= NULL
;
431 struct obj_section
*pc_section
;
432 enum minimal_symbol_type want_type
, other_type
;
434 want_type
= want_trampoline
? mst_solib_trampoline
: mst_text
;
435 other_type
= want_trampoline
? mst_text
: mst_solib_trampoline
;
437 /* PC has to be in a known section. This ensures that anything
438 beyond the end of the last segment doesn't appear to be part of
439 the last function in the last segment. */
440 pc_section
= find_pc_section (pc
);
441 if (pc_section
== NULL
)
444 /* We can not require the symbol found to be in pc_section, because
445 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
446 symbol - but find_pc_section won't return an absolute section and
447 hence the code below would skip over absolute symbols. We can
448 still take advantage of the call to find_pc_section, though - the
449 object file still must match. In case we have separate debug
450 files, search both the file and its separate debug file. There's
451 no telling which one will have the minimal symbols. */
453 objfile
= pc_section
->objfile
;
454 if (objfile
->separate_debug_objfile
)
455 objfile
= objfile
->separate_debug_objfile
;
457 for (; objfile
!= NULL
; objfile
= objfile
->separate_debug_objfile_backlink
)
459 /* If this objfile has a minimal symbol table, go search it using
460 a binary search. Note that a minimal symbol table always consists
461 of at least two symbols, a "real" symbol and the terminating
462 "null symbol". If there are no real symbols, then there is no
463 minimal symbol table at all. */
465 if (objfile
->minimal_symbol_count
> 0)
467 int best_zero_sized
= -1;
469 msymbol
= objfile
->msymbols
;
471 hi
= objfile
->minimal_symbol_count
- 1;
473 /* This code assumes that the minimal symbols are sorted by
474 ascending address values. If the pc value is greater than or
475 equal to the first symbol's address, then some symbol in this
476 minimal symbol table is a suitable candidate for being the
477 "best" symbol. This includes the last real symbol, for cases
478 where the pc value is larger than any address in this vector.
480 By iterating until the address associated with the current
481 hi index (the endpoint of the test interval) is less than
482 or equal to the desired pc value, we accomplish two things:
483 (1) the case where the pc value is larger than any minimal
484 symbol address is trivially solved, (2) the address associated
485 with the hi index is always the one we want when the interation
486 terminates. In essence, we are iterating the test interval
487 down until the pc value is pushed out of it from the high end.
489 Warning: this code is trickier than it would appear at first. */
491 /* Should also require that pc is <= end of objfile. FIXME! */
492 if (pc
>= SYMBOL_VALUE_ADDRESS (&msymbol
[lo
]))
494 while (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
]) > pc
)
496 /* pc is still strictly less than highest address */
497 /* Note "new" will always be >= lo */
499 if ((SYMBOL_VALUE_ADDRESS (&msymbol
[new]) >= pc
) ||
510 /* If we have multiple symbols at the same address, we want
511 hi to point to the last one. That way we can find the
512 right symbol if it has an index greater than hi. */
513 while (hi
< objfile
->minimal_symbol_count
- 1
514 && (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
515 == SYMBOL_VALUE_ADDRESS (&msymbol
[hi
+ 1])))
518 /* Skip various undesirable symbols. */
521 /* Skip any absolute symbols. This is apparently
522 what adb and dbx do, and is needed for the CM-5.
523 There are two known possible problems: (1) on
524 ELF, apparently end, edata, etc. are absolute.
525 Not sure ignoring them here is a big deal, but if
526 we want to use them, the fix would go in
527 elfread.c. (2) I think shared library entry
528 points on the NeXT are absolute. If we want
529 special handling for this it probably should be
530 triggered by a special mst_abs_or_lib or some
533 if (msymbol
[hi
].type
== mst_abs
)
539 /* If SECTION was specified, skip any symbol from
542 /* Some types of debug info, such as COFF,
543 don't fill the bfd_section member, so don't
544 throw away symbols on those platforms. */
545 && SYMBOL_BFD_SECTION (&msymbol
[hi
]) != NULL
546 && (!matching_bfd_sections
547 (SYMBOL_BFD_SECTION (&msymbol
[hi
]), section
)))
553 /* If we are looking for a trampoline and this is a
554 text symbol, or the other way around, check the
555 preceeding symbol too. If they are otherwise
556 identical prefer that one. */
558 && MSYMBOL_TYPE (&msymbol
[hi
]) == other_type
559 && MSYMBOL_TYPE (&msymbol
[hi
- 1]) == want_type
560 && (MSYMBOL_SIZE (&msymbol
[hi
])
561 == MSYMBOL_SIZE (&msymbol
[hi
- 1]))
562 && (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
563 == SYMBOL_VALUE_ADDRESS (&msymbol
[hi
- 1]))
564 && (SYMBOL_BFD_SECTION (&msymbol
[hi
])
565 == SYMBOL_BFD_SECTION (&msymbol
[hi
- 1])))
571 /* If the minimal symbol has a zero size, save it
572 but keep scanning backwards looking for one with
573 a non-zero size. A zero size may mean that the
574 symbol isn't an object or function (e.g. a
575 label), or it may just mean that the size was not
577 if (MSYMBOL_SIZE (&msymbol
[hi
]) == 0
578 && best_zero_sized
== -1)
580 best_zero_sized
= hi
;
585 /* If we are past the end of the current symbol, try
586 the previous symbol if it has a larger overlapping
587 size. This happens on i686-pc-linux-gnu with glibc;
588 the nocancel variants of system calls are inside
589 the cancellable variants, but both have sizes. */
591 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
592 && pc
>= (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
593 + MSYMBOL_SIZE (&msymbol
[hi
]))
594 && pc
< (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
- 1])
595 + MSYMBOL_SIZE (&msymbol
[hi
- 1])))
601 /* Otherwise, this symbol must be as good as we're going
606 /* If HI has a zero size, and best_zero_sized is set,
607 then we had two or more zero-sized symbols; prefer
608 the first one we found (which may have a higher
609 address). Also, if we ran off the end, be sure
611 if (best_zero_sized
!= -1
612 && (hi
< 0 || MSYMBOL_SIZE (&msymbol
[hi
]) == 0))
613 hi
= best_zero_sized
;
615 /* If the minimal symbol has a non-zero size, and this
616 PC appears to be outside the symbol's contents, then
617 refuse to use this symbol. If we found a zero-sized
618 symbol with an address greater than this symbol's,
619 use that instead. We assume that if symbols have
620 specified sizes, they do not overlap. */
623 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
624 && pc
>= (SYMBOL_VALUE_ADDRESS (&msymbol
[hi
])
625 + MSYMBOL_SIZE (&msymbol
[hi
])))
627 if (best_zero_sized
!= -1)
628 hi
= best_zero_sized
;
630 /* Go on to the next object file. */
634 /* The minimal symbol indexed by hi now is the best one in this
635 objfile's minimal symbol table. See if it is the best one
639 && ((best_symbol
== NULL
) ||
640 (SYMBOL_VALUE_ADDRESS (best_symbol
) <
641 SYMBOL_VALUE_ADDRESS (&msymbol
[hi
]))))
643 best_symbol
= &msymbol
[hi
];
648 return (best_symbol
);
651 struct minimal_symbol
*
652 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc
, asection
*section
)
654 return lookup_minimal_symbol_by_pc_section_1 (pc
, section
, 0);
657 /* Backward compatibility: search through the minimal symbol table
658 for a matching PC (no section given) */
660 struct minimal_symbol
*
661 lookup_minimal_symbol_by_pc (CORE_ADDR pc
)
663 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
664 force the section but that (well unless you're doing overlay
665 debugging) always returns NULL making the call somewhat useless. */
666 struct obj_section
*section
= find_pc_section (pc
);
669 return lookup_minimal_symbol_by_pc_section (pc
, section
->the_bfd_section
);
673 /* Return leading symbol character for a BFD. If BFD is NULL,
674 return the leading symbol character from the main objfile. */
676 static int get_symbol_leading_char (bfd
*);
679 get_symbol_leading_char (bfd
*abfd
)
682 return bfd_get_symbol_leading_char (abfd
);
683 if (symfile_objfile
!= NULL
&& symfile_objfile
->obfd
!= NULL
)
684 return bfd_get_symbol_leading_char (symfile_objfile
->obfd
);
688 /* Prepare to start collecting minimal symbols. Note that presetting
689 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal
690 symbol to allocate the memory for the first bunch. */
693 init_minimal_symbol_collection (void)
697 msym_bunch_index
= BUNCH_SIZE
;
701 prim_record_minimal_symbol (const char *name
, CORE_ADDR address
,
702 enum minimal_symbol_type ms_type
,
703 struct objfile
*objfile
)
711 case mst_solib_trampoline
:
712 section
= SECT_OFF_TEXT (objfile
);
716 section
= SECT_OFF_DATA (objfile
);
720 section
= SECT_OFF_BSS (objfile
);
726 prim_record_minimal_symbol_and_info (name
, address
, ms_type
,
727 NULL
, section
, NULL
, objfile
);
730 /* Record a minimal symbol in the msym bunches. Returns the symbol
733 struct minimal_symbol
*
734 prim_record_minimal_symbol_and_info (const char *name
, CORE_ADDR address
,
735 enum minimal_symbol_type ms_type
,
736 char *info
, int section
,
737 asection
*bfd_section
,
738 struct objfile
*objfile
)
740 struct msym_bunch
*new;
741 struct minimal_symbol
*msymbol
;
743 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
744 the minimal symbols, because if there is also another symbol
745 at the same address (e.g. the first function of the file),
746 lookup_minimal_symbol_by_pc would have no way of getting the
748 if (ms_type
== mst_file_text
&& name
[0] == 'g'
749 && (strcmp (name
, GCC_COMPILED_FLAG_SYMBOL
) == 0
750 || strcmp (name
, GCC2_COMPILED_FLAG_SYMBOL
) == 0))
753 /* It's safe to strip the leading char here once, since the name
754 is also stored stripped in the minimal symbol table. */
755 if (name
[0] == get_symbol_leading_char (objfile
->obfd
))
758 if (ms_type
== mst_file_text
&& strncmp (name
, "__gnu_compiled", 14) == 0)
761 if (msym_bunch_index
== BUNCH_SIZE
)
763 new = (struct msym_bunch
*) xmalloc (sizeof (struct msym_bunch
));
764 msym_bunch_index
= 0;
765 new->next
= msym_bunch
;
768 msymbol
= &msym_bunch
->contents
[msym_bunch_index
];
769 SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol
, language_unknown
);
770 SYMBOL_LANGUAGE (msymbol
) = language_auto
;
771 SYMBOL_SET_NAMES (msymbol
, (char *)name
, strlen (name
), objfile
);
773 SYMBOL_VALUE_ADDRESS (msymbol
) = address
;
774 SYMBOL_SECTION (msymbol
) = section
;
775 SYMBOL_BFD_SECTION (msymbol
) = bfd_section
;
777 MSYMBOL_TYPE (msymbol
) = ms_type
;
778 /* FIXME: This info, if it remains, needs its own field. */
779 MSYMBOL_INFO (msymbol
) = info
; /* FIXME! */
780 MSYMBOL_SIZE (msymbol
) = 0;
782 /* The hash pointers must be cleared! If they're not,
783 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
784 msymbol
->hash_next
= NULL
;
785 msymbol
->demangled_hash_next
= NULL
;
789 OBJSTAT (objfile
, n_minsyms
++);
793 /* Compare two minimal symbols by address and return a signed result based
794 on unsigned comparisons, so that we sort into unsigned numeric order.
795 Within groups with the same address, sort by name. */
798 compare_minimal_symbols (const void *fn1p
, const void *fn2p
)
800 const struct minimal_symbol
*fn1
;
801 const struct minimal_symbol
*fn2
;
803 fn1
= (const struct minimal_symbol
*) fn1p
;
804 fn2
= (const struct minimal_symbol
*) fn2p
;
806 if (SYMBOL_VALUE_ADDRESS (fn1
) < SYMBOL_VALUE_ADDRESS (fn2
))
808 return (-1); /* addr 1 is less than addr 2 */
810 else if (SYMBOL_VALUE_ADDRESS (fn1
) > SYMBOL_VALUE_ADDRESS (fn2
))
812 return (1); /* addr 1 is greater than addr 2 */
815 /* addrs are equal: sort by name */
817 char *name1
= SYMBOL_LINKAGE_NAME (fn1
);
818 char *name2
= SYMBOL_LINKAGE_NAME (fn2
);
820 if (name1
&& name2
) /* both have names */
821 return strcmp (name1
, name2
);
823 return 1; /* fn1 has no name, so it is "less" */
824 else if (name1
) /* fn2 has no name, so it is "less" */
827 return (0); /* neither has a name, so they're equal. */
831 /* Discard the currently collected minimal symbols, if any. If we wish
832 to save them for later use, we must have already copied them somewhere
833 else before calling this function.
835 FIXME: We could allocate the minimal symbol bunches on their own
836 obstack and then simply blow the obstack away when we are done with
837 it. Is it worth the extra trouble though? */
840 do_discard_minimal_symbols_cleanup (void *arg
)
842 struct msym_bunch
*next
;
844 while (msym_bunch
!= NULL
)
846 next
= msym_bunch
->next
;
853 make_cleanup_discard_minimal_symbols (void)
855 return make_cleanup (do_discard_minimal_symbols_cleanup
, 0);
860 /* Compact duplicate entries out of a minimal symbol table by walking
861 through the table and compacting out entries with duplicate addresses
862 and matching names. Return the number of entries remaining.
864 On entry, the table resides between msymbol[0] and msymbol[mcount].
865 On exit, it resides between msymbol[0] and msymbol[result_count].
867 When files contain multiple sources of symbol information, it is
868 possible for the minimal symbol table to contain many duplicate entries.
869 As an example, SVR4 systems use ELF formatted object files, which
870 usually contain at least two different types of symbol tables (a
871 standard ELF one and a smaller dynamic linking table), as well as
872 DWARF debugging information for files compiled with -g.
874 Without compacting, the minimal symbol table for gdb itself contains
875 over a 1000 duplicates, about a third of the total table size. Aside
876 from the potential trap of not noticing that two successive entries
877 identify the same location, this duplication impacts the time required
878 to linearly scan the table, which is done in a number of places. So we
879 just do one linear scan here and toss out the duplicates.
881 Note that we are not concerned here about recovering the space that
882 is potentially freed up, because the strings themselves are allocated
883 on the objfile_obstack, and will get automatically freed when the symbol
884 table is freed. The caller can free up the unused minimal symbols at
885 the end of the compacted region if their allocation strategy allows it.
887 Also note we only go up to the next to last entry within the loop
888 and then copy the last entry explicitly after the loop terminates.
890 Since the different sources of information for each symbol may
891 have different levels of "completeness", we may have duplicates
892 that have one entry with type "mst_unknown" and the other with a
893 known type. So if the one we are leaving alone has type mst_unknown,
894 overwrite its type with the type from the one we are compacting out. */
897 compact_minimal_symbols (struct minimal_symbol
*msymbol
, int mcount
,
898 struct objfile
*objfile
)
900 struct minimal_symbol
*copyfrom
;
901 struct minimal_symbol
*copyto
;
905 copyfrom
= copyto
= msymbol
;
906 while (copyfrom
< msymbol
+ mcount
- 1)
908 if (SYMBOL_VALUE_ADDRESS (copyfrom
)
909 == SYMBOL_VALUE_ADDRESS ((copyfrom
+ 1))
910 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom
),
911 SYMBOL_LINKAGE_NAME ((copyfrom
+ 1))) == 0)
913 if (MSYMBOL_TYPE ((copyfrom
+ 1)) == mst_unknown
)
915 MSYMBOL_TYPE ((copyfrom
+ 1)) = MSYMBOL_TYPE (copyfrom
);
920 *copyto
++ = *copyfrom
++;
922 *copyto
++ = *copyfrom
++;
923 mcount
= copyto
- msymbol
;
928 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
929 after compacting or sorting the table since the entries move around
930 thus causing the internal minimal_symbol pointers to become jumbled. */
933 build_minimal_symbol_hash_tables (struct objfile
*objfile
)
936 struct minimal_symbol
*msym
;
938 /* Clear the hash tables. */
939 for (i
= 0; i
< MINIMAL_SYMBOL_HASH_SIZE
; i
++)
941 objfile
->msymbol_hash
[i
] = 0;
942 objfile
->msymbol_demangled_hash
[i
] = 0;
945 /* Now, (re)insert the actual entries. */
946 for (i
= objfile
->minimal_symbol_count
, msym
= objfile
->msymbols
;
951 add_minsym_to_hash_table (msym
, objfile
->msymbol_hash
);
953 msym
->demangled_hash_next
= 0;
954 if (SYMBOL_SEARCH_NAME (msym
) != SYMBOL_LINKAGE_NAME (msym
))
955 add_minsym_to_demangled_hash_table (msym
,
956 objfile
->msymbol_demangled_hash
);
960 /* Add the minimal symbols in the existing bunches to the objfile's official
961 minimal symbol table. In most cases there is no minimal symbol table yet
962 for this objfile, and the existing bunches are used to create one. Once
963 in a while (for shared libraries for example), we add symbols (e.g. common
964 symbols) to an existing objfile.
966 Because of the way minimal symbols are collected, we generally have no way
967 of knowing what source language applies to any particular minimal symbol.
968 Specifically, we have no way of knowing if the minimal symbol comes from a
969 C++ compilation unit or not. So for the sake of supporting cached
970 demangled C++ names, we have no choice but to try and demangle each new one
971 that comes in. If the demangling succeeds, then we assume it is a C++
972 symbol and set the symbol's language and demangled name fields
973 appropriately. Note that in order to avoid unnecessary demanglings, and
974 allocating obstack space that subsequently can't be freed for the demangled
975 names, we mark all newly added symbols with language_auto. After
976 compaction of the minimal symbols, we go back and scan the entire minimal
977 symbol table looking for these new symbols. For each new symbol we attempt
978 to demangle it, and if successful, record it as a language_cplus symbol
979 and cache the demangled form on the symbol obstack. Symbols which don't
980 demangle are marked as language_unknown symbols, which inhibits future
981 attempts to demangle them if we later add more minimal symbols. */
984 install_minimal_symbols (struct objfile
*objfile
)
988 struct msym_bunch
*bunch
;
989 struct minimal_symbol
*msymbols
;
994 /* Allocate enough space in the obstack, into which we will gather the
995 bunches of new and existing minimal symbols, sort them, and then
996 compact out the duplicate entries. Once we have a final table,
997 we will give back the excess space. */
999 alloc_count
= msym_count
+ objfile
->minimal_symbol_count
+ 1;
1000 obstack_blank (&objfile
->objfile_obstack
,
1001 alloc_count
* sizeof (struct minimal_symbol
));
1002 msymbols
= (struct minimal_symbol
*)
1003 obstack_base (&objfile
->objfile_obstack
);
1005 /* Copy in the existing minimal symbols, if there are any. */
1007 if (objfile
->minimal_symbol_count
)
1008 memcpy ((char *) msymbols
, (char *) objfile
->msymbols
,
1009 objfile
->minimal_symbol_count
* sizeof (struct minimal_symbol
));
1011 /* Walk through the list of minimal symbol bunches, adding each symbol
1012 to the new contiguous array of symbols. Note that we start with the
1013 current, possibly partially filled bunch (thus we use the current
1014 msym_bunch_index for the first bunch we copy over), and thereafter
1015 each bunch is full. */
1017 mcount
= objfile
->minimal_symbol_count
;
1019 for (bunch
= msym_bunch
; bunch
!= NULL
; bunch
= bunch
->next
)
1021 for (bindex
= 0; bindex
< msym_bunch_index
; bindex
++, mcount
++)
1022 msymbols
[mcount
] = bunch
->contents
[bindex
];
1023 msym_bunch_index
= BUNCH_SIZE
;
1026 /* Sort the minimal symbols by address. */
1028 qsort (msymbols
, mcount
, sizeof (struct minimal_symbol
),
1029 compare_minimal_symbols
);
1031 /* Compact out any duplicates, and free up whatever space we are
1034 mcount
= compact_minimal_symbols (msymbols
, mcount
, objfile
);
1036 obstack_blank (&objfile
->objfile_obstack
,
1037 (mcount
+ 1 - alloc_count
) * sizeof (struct minimal_symbol
));
1038 msymbols
= (struct minimal_symbol
*)
1039 obstack_finish (&objfile
->objfile_obstack
);
1041 /* We also terminate the minimal symbol table with a "null symbol",
1042 which is *not* included in the size of the table. This makes it
1043 easier to find the end of the table when we are handed a pointer
1044 to some symbol in the middle of it. Zero out the fields in the
1045 "null symbol" allocated at the end of the array. Note that the
1046 symbol count does *not* include this null symbol, which is why it
1047 is indexed by mcount and not mcount-1. */
1049 SYMBOL_LINKAGE_NAME (&msymbols
[mcount
]) = NULL
;
1050 SYMBOL_VALUE_ADDRESS (&msymbols
[mcount
]) = 0;
1051 MSYMBOL_INFO (&msymbols
[mcount
]) = NULL
;
1052 MSYMBOL_SIZE (&msymbols
[mcount
]) = 0;
1053 MSYMBOL_TYPE (&msymbols
[mcount
]) = mst_unknown
;
1054 SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols
[mcount
], language_unknown
);
1056 /* Attach the minimal symbol table to the specified objfile.
1057 The strings themselves are also located in the objfile_obstack
1060 objfile
->minimal_symbol_count
= mcount
;
1061 objfile
->msymbols
= msymbols
;
1063 /* Try to guess the appropriate C++ ABI by looking at the names
1064 of the minimal symbols in the table. */
1068 for (i
= 0; i
< mcount
; i
++)
1070 /* If a symbol's name starts with _Z and was successfully
1071 demangled, then we can assume we've found a GNU v3 symbol.
1072 For now we set the C++ ABI globally; if the user is
1073 mixing ABIs then the user will need to "set cp-abi"
1075 const char *name
= SYMBOL_LINKAGE_NAME (&objfile
->msymbols
[i
]);
1076 if (name
[0] == '_' && name
[1] == 'Z'
1077 && SYMBOL_DEMANGLED_NAME (&objfile
->msymbols
[i
]) != NULL
)
1079 set_cp_abi_as_auto_default ("gnu-v3");
1085 /* Now build the hash tables; we can't do this incrementally
1086 at an earlier point since we weren't finished with the obstack
1087 yet. (And if the msymbol obstack gets moved, all the internal
1088 pointers to other msymbols need to be adjusted.) */
1089 build_minimal_symbol_hash_tables (objfile
);
1093 /* Sort all the minimal symbols in OBJFILE. */
1096 msymbols_sort (struct objfile
*objfile
)
1098 qsort (objfile
->msymbols
, objfile
->minimal_symbol_count
,
1099 sizeof (struct minimal_symbol
), compare_minimal_symbols
);
1100 build_minimal_symbol_hash_tables (objfile
);
1103 /* Check if PC is in a shared library trampoline code stub.
1104 Return minimal symbol for the trampoline entry or NULL if PC is not
1105 in a trampoline code stub. */
1107 struct minimal_symbol
*
1108 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc
)
1110 struct obj_section
*section
= find_pc_section (pc
);
1111 struct minimal_symbol
*msymbol
;
1113 if (section
== NULL
)
1115 msymbol
= lookup_minimal_symbol_by_pc_section_1 (pc
, section
->the_bfd_section
,
1118 if (msymbol
!= NULL
&& MSYMBOL_TYPE (msymbol
) == mst_solib_trampoline
)
1123 /* If PC is in a shared library trampoline code stub, return the
1124 address of the `real' function belonging to the stub.
1125 Return 0 if PC is not in a trampoline code stub or if the real
1126 function is not found in the minimal symbol table.
1128 We may fail to find the right function if a function with the
1129 same name is defined in more than one shared library, but this
1130 is considered bad programming style. We could return 0 if we find
1131 a duplicate function in case this matters someday. */
1134 find_solib_trampoline_target (struct frame_info
*frame
, CORE_ADDR pc
)
1136 struct objfile
*objfile
;
1137 struct minimal_symbol
*msymbol
;
1138 struct minimal_symbol
*tsymbol
= lookup_solib_trampoline_symbol_by_pc (pc
);
1140 if (tsymbol
!= NULL
)
1142 ALL_MSYMBOLS (objfile
, msymbol
)
1144 if (MSYMBOL_TYPE (msymbol
) == mst_text
1145 && strcmp (SYMBOL_LINKAGE_NAME (msymbol
),
1146 SYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1147 return SYMBOL_VALUE_ADDRESS (msymbol
);
1149 /* Also handle minimal symbols pointing to function descriptors. */
1150 if (MSYMBOL_TYPE (msymbol
) == mst_data
1151 && strcmp (SYMBOL_LINKAGE_NAME (msymbol
),
1152 SYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1155 func
= gdbarch_convert_from_func_ptr_addr
1156 (get_objfile_arch (objfile
),
1157 SYMBOL_VALUE_ADDRESS (msymbol
),
1160 /* Ignore data symbols that are not function descriptors. */
1161 if (func
!= SYMBOL_VALUE_ADDRESS (msymbol
))