1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2014 Free Software Foundation, Inc.
3 Contributed by Cygnus Support, using pieces from other GDB modules.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 /* This file contains support routines for creating, manipulating, and
22 destroying minimal symbol tables.
24 Minimal symbol tables are used to hold some very basic information about
25 all defined global symbols (text, data, bss, abs, etc). The only two
26 required pieces of information are the symbol's name and the address
27 associated with that symbol.
29 In many cases, even if a file was compiled with no special options for
30 debugging at all, as long as was not stripped it will contain sufficient
31 information to build useful minimal symbol tables using this structure.
33 Even when a file contains enough debugging information to build a full
34 symbol table, these minimal symbols are still useful for quickly mapping
35 between names and addresses, and vice versa. They are also sometimes used
36 to figure out what full symbol table entries need to be read in. */
44 #include "filenames.h"
51 #include "cp-support.h"
53 #include "cli/cli-utils.h"
55 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
56 At the end, copy them all into one newly allocated location on an objfile's
57 per-BFD storage obstack. */
59 #define BUNCH_SIZE 127
63 struct msym_bunch
*next
;
64 struct minimal_symbol contents
[BUNCH_SIZE
];
67 /* Bunch currently being filled up.
68 The next field points to chain of filled bunches. */
70 static struct msym_bunch
*msym_bunch
;
72 /* Number of slots filled in current bunch. */
74 static int msym_bunch_index
;
76 /* Total number of minimal symbols recorded so far for the objfile. */
78 static int msym_count
;
83 msymbol_hash_iw (const char *string
)
85 unsigned int hash
= 0;
87 while (*string
&& *string
!= '(')
89 string
= skip_spaces_const (string
);
90 if (*string
&& *string
!= '(')
92 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
102 msymbol_hash (const char *string
)
104 unsigned int hash
= 0;
106 for (; *string
; ++string
)
107 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
111 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
113 add_minsym_to_hash_table (struct minimal_symbol
*sym
,
114 struct minimal_symbol
**table
)
116 if (sym
->hash_next
== NULL
)
119 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
121 sym
->hash_next
= table
[hash
];
126 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
129 add_minsym_to_demangled_hash_table (struct minimal_symbol
*sym
,
130 struct minimal_symbol
**table
)
132 if (sym
->demangled_hash_next
== NULL
)
134 unsigned int hash
= msymbol_hash_iw (MSYMBOL_SEARCH_NAME (sym
))
135 % MINIMAL_SYMBOL_HASH_SIZE
;
137 sym
->demangled_hash_next
= table
[hash
];
142 /* Look through all the current minimal symbol tables and find the
143 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
144 the search to that objfile. If SFILE is non-NULL, the only file-scope
145 symbols considered will be from that source file (global symbols are
146 still preferred). Returns a pointer to the minimal symbol that
147 matches, or NULL if no match is found.
149 Note: One instance where there may be duplicate minimal symbols with
150 the same name is when the symbol tables for a shared library and the
151 symbol tables for an executable contain global symbols with the same
152 names (the dynamic linker deals with the duplication).
154 It's also possible to have minimal symbols with different mangled
155 names, but identical demangled names. For example, the GNU C++ v3
156 ABI requires the generation of two (or perhaps three) copies of
157 constructor functions --- "in-charge", "not-in-charge", and
158 "allocate" copies; destructors may be duplicated as well.
159 Obviously, there must be distinct mangled names for each of these,
160 but the demangled names are all the same: S::S or S::~S. */
162 struct bound_minimal_symbol
163 lookup_minimal_symbol (const char *name
, const char *sfile
,
164 struct objfile
*objf
)
166 struct objfile
*objfile
;
167 struct bound_minimal_symbol found_symbol
= { NULL
, NULL
};
168 struct bound_minimal_symbol found_file_symbol
= { NULL
, NULL
};
169 struct bound_minimal_symbol trampoline_symbol
= { NULL
, NULL
};
171 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
172 unsigned int dem_hash
= msymbol_hash_iw (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
174 int needtofreename
= 0;
175 const char *modified_name
;
178 sfile
= lbasename (sfile
);
180 /* For C++, canonicalize the input name. */
181 modified_name
= name
;
182 if (current_language
->la_language
== language_cplus
)
184 char *cname
= cp_canonicalize_string (name
);
188 modified_name
= cname
;
193 for (objfile
= object_files
;
194 objfile
!= NULL
&& found_symbol
.minsym
== NULL
;
195 objfile
= objfile
->next
)
197 struct minimal_symbol
*msymbol
;
199 if (objf
== NULL
|| objf
== objfile
200 || objf
== objfile
->separate_debug_objfile_backlink
)
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
.minsym
== NULL
; pass
++)
208 /* Select hash list according to pass. */
210 msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
212 msymbol
= objfile
->per_bfd
->msymbol_demangled_hash
[dem_hash
];
214 while (msymbol
!= NULL
&& found_symbol
.minsym
== NULL
)
220 int (*cmp
) (const char *, const char *);
222 cmp
= (case_sensitivity
== case_sensitive_on
223 ? strcmp
: strcasecmp
);
224 match
= cmp (MSYMBOL_LINKAGE_NAME (msymbol
),
229 /* The function respects CASE_SENSITIVITY. */
230 match
= MSYMBOL_MATCHES_SEARCH_NAME (msymbol
,
236 switch (MSYMBOL_TYPE (msymbol
))
242 || filename_cmp (msymbol
->filename
, sfile
) == 0)
244 found_file_symbol
.minsym
= msymbol
;
245 found_file_symbol
.objfile
= objfile
;
249 case mst_solib_trampoline
:
251 /* If a trampoline symbol is found, we prefer to
252 keep looking for the *real* symbol. If the
253 actual symbol is not found, then we'll use the
255 if (trampoline_symbol
.minsym
== NULL
)
257 trampoline_symbol
.minsym
= msymbol
;
258 trampoline_symbol
.objfile
= objfile
;
264 found_symbol
.minsym
= msymbol
;
265 found_symbol
.objfile
= objfile
;
270 /* Find the next symbol on the hash chain. */
272 msymbol
= msymbol
->hash_next
;
274 msymbol
= msymbol
->demangled_hash_next
;
281 xfree ((void *) modified_name
);
283 /* External symbols are best. */
284 if (found_symbol
.minsym
!= NULL
)
287 /* File-local symbols are next best. */
288 if (found_file_symbol
.minsym
!= NULL
)
289 return found_file_symbol
;
291 /* Symbols for shared library trampolines are next best. */
292 return trampoline_symbol
;
297 struct bound_minimal_symbol
298 lookup_bound_minimal_symbol (const char *name
)
300 return lookup_minimal_symbol (name
, NULL
, NULL
);
306 iterate_over_minimal_symbols (struct objfile
*objf
, const char *name
,
307 void (*callback
) (struct minimal_symbol
*,
312 struct minimal_symbol
*iter
;
313 int (*cmp
) (const char *, const char *);
315 /* The first pass is over the ordinary hash table. */
316 hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
317 iter
= objf
->per_bfd
->msymbol_hash
[hash
];
318 cmp
= (case_sensitivity
== case_sensitive_on
? strcmp
: strcasecmp
);
321 if (cmp (MSYMBOL_LINKAGE_NAME (iter
), name
) == 0)
322 (*callback
) (iter
, user_data
);
323 iter
= iter
->hash_next
;
326 /* The second pass is over the demangled table. */
327 hash
= msymbol_hash_iw (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
328 iter
= objf
->per_bfd
->msymbol_demangled_hash
[hash
];
331 if (MSYMBOL_MATCHES_SEARCH_NAME (iter
, name
))
332 (*callback
) (iter
, user_data
);
333 iter
= iter
->demangled_hash_next
;
339 struct bound_minimal_symbol
340 lookup_minimal_symbol_text (const char *name
, struct objfile
*objf
)
342 struct objfile
*objfile
;
343 struct minimal_symbol
*msymbol
;
344 struct bound_minimal_symbol found_symbol
= { NULL
, NULL
};
345 struct bound_minimal_symbol found_file_symbol
= { NULL
, NULL
};
347 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
349 for (objfile
= object_files
;
350 objfile
!= NULL
&& found_symbol
.minsym
== NULL
;
351 objfile
= objfile
->next
)
353 if (objf
== NULL
|| objf
== objfile
354 || objf
== objfile
->separate_debug_objfile_backlink
)
356 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
357 msymbol
!= NULL
&& found_symbol
.minsym
== NULL
;
358 msymbol
= msymbol
->hash_next
)
360 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
361 (MSYMBOL_TYPE (msymbol
) == mst_text
362 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
363 || MSYMBOL_TYPE (msymbol
) == mst_file_text
))
365 switch (MSYMBOL_TYPE (msymbol
))
368 found_file_symbol
.minsym
= msymbol
;
369 found_file_symbol
.objfile
= objfile
;
372 found_symbol
.minsym
= msymbol
;
373 found_symbol
.objfile
= objfile
;
380 /* External symbols are best. */
381 if (found_symbol
.minsym
)
384 /* File-local symbols are next best. */
385 return found_file_symbol
;
390 struct minimal_symbol
*
391 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc
, const char *name
,
392 struct objfile
*objf
)
394 struct objfile
*objfile
;
395 struct minimal_symbol
*msymbol
;
397 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
399 for (objfile
= object_files
;
401 objfile
= objfile
->next
)
403 if (objf
== NULL
|| objf
== objfile
404 || objf
== objfile
->separate_debug_objfile_backlink
)
406 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
408 msymbol
= msymbol
->hash_next
)
410 if (MSYMBOL_VALUE_ADDRESS (objfile
, msymbol
) == pc
411 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0)
422 struct bound_minimal_symbol
423 lookup_minimal_symbol_solib_trampoline (const char *name
,
424 struct objfile
*objf
)
426 struct objfile
*objfile
;
427 struct minimal_symbol
*msymbol
;
428 struct bound_minimal_symbol found_symbol
= { NULL
, NULL
};
430 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
432 for (objfile
= object_files
;
434 objfile
= objfile
->next
)
436 if (objf
== NULL
|| objf
== objfile
437 || objf
== objfile
->separate_debug_objfile_backlink
)
439 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
441 msymbol
= msymbol
->hash_next
)
443 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
444 MSYMBOL_TYPE (msymbol
) == mst_solib_trampoline
)
446 found_symbol
.objfile
= objfile
;
447 found_symbol
.minsym
= msymbol
;
457 /* A helper function that makes *PC section-relative. This searches
458 the sections of OBJFILE and if *PC is in a section, it subtracts
459 the section offset and returns true. Otherwise it returns
463 frob_address (struct objfile
*objfile
, CORE_ADDR
*pc
)
465 struct obj_section
*iter
;
467 ALL_OBJFILE_OSECTIONS (objfile
, iter
)
469 if (*pc
>= obj_section_addr (iter
) && *pc
< obj_section_endaddr (iter
))
471 *pc
-= obj_section_offset (iter
);
479 /* Search through the minimal symbol table for each objfile and find
480 the symbol whose address is the largest address that is still less
481 than or equal to PC, and matches SECTION (which is not NULL).
482 Returns a pointer to the minimal symbol if such a symbol is found,
483 or NULL if PC is not in a suitable range.
484 Note that we need to look through ALL the minimal symbol tables
485 before deciding on the symbol that comes closest to the specified PC.
486 This is because objfiles can overlap, for example objfile A has .text
487 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
490 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
491 there are text and trampoline symbols at the same address.
492 Otherwise prefer mst_text symbols. */
494 static struct bound_minimal_symbol
495 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc_in
,
496 struct obj_section
*section
,
502 struct objfile
*objfile
;
503 struct minimal_symbol
*msymbol
;
504 struct minimal_symbol
*best_symbol
= NULL
;
505 struct objfile
*best_objfile
= NULL
;
506 struct bound_minimal_symbol result
;
507 enum minimal_symbol_type want_type
, other_type
;
509 want_type
= want_trampoline
? mst_solib_trampoline
: mst_text
;
510 other_type
= want_trampoline
? mst_text
: mst_solib_trampoline
;
512 /* We can not require the symbol found to be in section, because
513 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
514 symbol - but find_pc_section won't return an absolute section and
515 hence the code below would skip over absolute symbols. We can
516 still take advantage of the call to find_pc_section, though - the
517 object file still must match. In case we have separate debug
518 files, search both the file and its separate debug file. There's
519 no telling which one will have the minimal symbols. */
521 gdb_assert (section
!= NULL
);
523 for (objfile
= section
->objfile
;
525 objfile
= objfile_separate_debug_iterate (section
->objfile
, objfile
))
527 CORE_ADDR pc
= pc_in
;
529 /* If this objfile has a minimal symbol table, go search it using
530 a binary search. Note that a minimal symbol table always consists
531 of at least two symbols, a "real" symbol and the terminating
532 "null symbol". If there are no real symbols, then there is no
533 minimal symbol table at all. */
535 if (objfile
->per_bfd
->minimal_symbol_count
> 0)
537 int best_zero_sized
= -1;
539 msymbol
= objfile
->per_bfd
->msymbols
;
541 hi
= objfile
->per_bfd
->minimal_symbol_count
- 1;
543 /* This code assumes that the minimal symbols are sorted by
544 ascending address values. If the pc value is greater than or
545 equal to the first symbol's address, then some symbol in this
546 minimal symbol table is a suitable candidate for being the
547 "best" symbol. This includes the last real symbol, for cases
548 where the pc value is larger than any address in this vector.
550 By iterating until the address associated with the current
551 hi index (the endpoint of the test interval) is less than
552 or equal to the desired pc value, we accomplish two things:
553 (1) the case where the pc value is larger than any minimal
554 symbol address is trivially solved, (2) the address associated
555 with the hi index is always the one we want when the interation
556 terminates. In essence, we are iterating the test interval
557 down until the pc value is pushed out of it from the high end.
559 Warning: this code is trickier than it would appear at first. */
561 if (frob_address (objfile
, &pc
)
562 && pc
>= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[lo
]))
564 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]) > pc
)
566 /* pc is still strictly less than highest address. */
567 /* Note "new" will always be >= lo. */
569 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[new]) >= pc
)
580 /* If we have multiple symbols at the same address, we want
581 hi to point to the last one. That way we can find the
582 right symbol if it has an index greater than hi. */
583 while (hi
< objfile
->per_bfd
->minimal_symbol_count
- 1
584 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
585 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
+ 1])))
588 /* Skip various undesirable symbols. */
591 /* Skip any absolute symbols. This is apparently
592 what adb and dbx do, and is needed for the CM-5.
593 There are two known possible problems: (1) on
594 ELF, apparently end, edata, etc. are absolute.
595 Not sure ignoring them here is a big deal, but if
596 we want to use them, the fix would go in
597 elfread.c. (2) I think shared library entry
598 points on the NeXT are absolute. If we want
599 special handling for this it probably should be
600 triggered by a special mst_abs_or_lib or some
603 if (MSYMBOL_TYPE (&msymbol
[hi
]) == mst_abs
)
609 /* If SECTION was specified, skip any symbol from
612 /* Some types of debug info, such as COFF,
613 don't fill the bfd_section member, so don't
614 throw away symbols on those platforms. */
615 && MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]) != NULL
616 && (!matching_obj_sections
617 (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]),
624 /* If we are looking for a trampoline and this is a
625 text symbol, or the other way around, check the
626 preceding symbol too. If they are otherwise
627 identical prefer that one. */
629 && MSYMBOL_TYPE (&msymbol
[hi
]) == other_type
630 && MSYMBOL_TYPE (&msymbol
[hi
- 1]) == want_type
631 && (MSYMBOL_SIZE (&msymbol
[hi
])
632 == MSYMBOL_SIZE (&msymbol
[hi
- 1]))
633 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
634 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1]))
635 && (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
])
636 == MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
- 1])))
642 /* If the minimal symbol has a zero size, save it
643 but keep scanning backwards looking for one with
644 a non-zero size. A zero size may mean that the
645 symbol isn't an object or function (e.g. a
646 label), or it may just mean that the size was not
648 if (MSYMBOL_SIZE (&msymbol
[hi
]) == 0
649 && best_zero_sized
== -1)
651 best_zero_sized
= hi
;
656 /* If we are past the end of the current symbol, try
657 the previous symbol if it has a larger overlapping
658 size. This happens on i686-pc-linux-gnu with glibc;
659 the nocancel variants of system calls are inside
660 the cancellable variants, but both have sizes. */
662 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
663 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
664 + MSYMBOL_SIZE (&msymbol
[hi
]))
665 && pc
< (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1])
666 + MSYMBOL_SIZE (&msymbol
[hi
- 1])))
672 /* Otherwise, this symbol must be as good as we're going
677 /* If HI has a zero size, and best_zero_sized is set,
678 then we had two or more zero-sized symbols; prefer
679 the first one we found (which may have a higher
680 address). Also, if we ran off the end, be sure
682 if (best_zero_sized
!= -1
683 && (hi
< 0 || MSYMBOL_SIZE (&msymbol
[hi
]) == 0))
684 hi
= best_zero_sized
;
686 /* If the minimal symbol has a non-zero size, and this
687 PC appears to be outside the symbol's contents, then
688 refuse to use this symbol. If we found a zero-sized
689 symbol with an address greater than this symbol's,
690 use that instead. We assume that if symbols have
691 specified sizes, they do not overlap. */
694 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
695 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
696 + MSYMBOL_SIZE (&msymbol
[hi
])))
698 if (best_zero_sized
!= -1)
699 hi
= best_zero_sized
;
701 /* Go on to the next object file. */
705 /* The minimal symbol indexed by hi now is the best one in this
706 objfile's minimal symbol table. See if it is the best one
710 && ((best_symbol
== NULL
) ||
711 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol
) <
712 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]))))
714 best_symbol
= &msymbol
[hi
];
715 best_objfile
= objfile
;
721 result
.minsym
= best_symbol
;
722 result
.objfile
= best_objfile
;
726 struct bound_minimal_symbol
727 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc
, struct obj_section
*section
)
731 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
732 force the section but that (well unless you're doing overlay
733 debugging) always returns NULL making the call somewhat useless. */
734 section
= find_pc_section (pc
);
737 struct bound_minimal_symbol result
;
739 memset (&result
, 0, sizeof (result
));
743 return lookup_minimal_symbol_by_pc_section_1 (pc
, section
, 0);
748 struct bound_minimal_symbol
749 lookup_minimal_symbol_by_pc (CORE_ADDR pc
)
751 struct obj_section
*section
= find_pc_section (pc
);
755 struct bound_minimal_symbol result
;
757 memset (&result
, 0, sizeof (result
));
760 return lookup_minimal_symbol_by_pc_section_1 (pc
, section
, 0);
763 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
766 in_gnu_ifunc_stub (CORE_ADDR pc
)
768 struct bound_minimal_symbol msymbol
= lookup_minimal_symbol_by_pc (pc
);
770 return msymbol
.minsym
&& MSYMBOL_TYPE (msymbol
.minsym
) == mst_text_gnu_ifunc
;
773 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
776 stub_gnu_ifunc_resolve_addr (struct gdbarch
*gdbarch
, CORE_ADDR pc
)
778 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
779 "the ELF support compiled in."),
780 paddress (gdbarch
, pc
));
783 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
786 stub_gnu_ifunc_resolve_name (const char *function_name
,
787 CORE_ADDR
*function_address_p
)
789 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
790 "the ELF support compiled in."),
794 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
797 stub_gnu_ifunc_resolver_stop (struct breakpoint
*b
)
799 internal_error (__FILE__
, __LINE__
,
800 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
803 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
806 stub_gnu_ifunc_resolver_return_stop (struct breakpoint
*b
)
808 internal_error (__FILE__
, __LINE__
,
809 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
812 /* See elf_gnu_ifunc_fns for its real implementation. */
814 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns
=
816 stub_gnu_ifunc_resolve_addr
,
817 stub_gnu_ifunc_resolve_name
,
818 stub_gnu_ifunc_resolver_stop
,
819 stub_gnu_ifunc_resolver_return_stop
,
822 /* A placeholder for &elf_gnu_ifunc_fns. */
824 const struct gnu_ifunc_fns
*gnu_ifunc_fns_p
= &stub_gnu_ifunc_fns
;
828 struct bound_minimal_symbol
829 lookup_minimal_symbol_and_objfile (const char *name
)
831 struct bound_minimal_symbol result
;
832 struct objfile
*objfile
;
833 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
835 ALL_OBJFILES (objfile
)
837 struct minimal_symbol
*msym
;
839 for (msym
= objfile
->per_bfd
->msymbol_hash
[hash
];
841 msym
= msym
->hash_next
)
843 if (strcmp (MSYMBOL_LINKAGE_NAME (msym
), name
) == 0)
845 result
.minsym
= msym
;
846 result
.objfile
= objfile
;
852 memset (&result
, 0, sizeof (result
));
857 /* Return leading symbol character for a BFD. If BFD is NULL,
858 return the leading symbol character from the main objfile. */
861 get_symbol_leading_char (bfd
*abfd
)
864 return bfd_get_symbol_leading_char (abfd
);
865 if (symfile_objfile
!= NULL
&& symfile_objfile
->obfd
!= NULL
)
866 return bfd_get_symbol_leading_char (symfile_objfile
->obfd
);
873 init_minimal_symbol_collection (void)
877 /* Note that presetting msym_bunch_index to BUNCH_SIZE causes the
878 first call to save a minimal symbol to allocate the memory for
880 msym_bunch_index
= BUNCH_SIZE
;
886 prim_record_minimal_symbol (const char *name
, CORE_ADDR address
,
887 enum minimal_symbol_type ms_type
,
888 struct objfile
*objfile
)
895 case mst_text_gnu_ifunc
:
897 case mst_solib_trampoline
:
898 section
= SECT_OFF_TEXT (objfile
);
902 section
= SECT_OFF_DATA (objfile
);
906 section
= SECT_OFF_BSS (objfile
);
912 prim_record_minimal_symbol_and_info (name
, address
, ms_type
,
918 struct minimal_symbol
*
919 prim_record_minimal_symbol_full (const char *name
, int name_len
, int copy_name
,
921 enum minimal_symbol_type ms_type
,
923 struct objfile
*objfile
)
925 struct obj_section
*obj_section
;
926 struct msym_bunch
*new;
927 struct minimal_symbol
*msymbol
;
929 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
930 the minimal symbols, because if there is also another symbol
931 at the same address (e.g. the first function of the file),
932 lookup_minimal_symbol_by_pc would have no way of getting the
934 if (ms_type
== mst_file_text
&& name
[0] == 'g'
935 && (strcmp (name
, GCC_COMPILED_FLAG_SYMBOL
) == 0
936 || strcmp (name
, GCC2_COMPILED_FLAG_SYMBOL
) == 0))
939 /* It's safe to strip the leading char here once, since the name
940 is also stored stripped in the minimal symbol table. */
941 if (name
[0] == get_symbol_leading_char (objfile
->obfd
))
947 if (ms_type
== mst_file_text
&& strncmp (name
, "__gnu_compiled", 14) == 0)
950 if (msym_bunch_index
== BUNCH_SIZE
)
952 new = XCNEW (struct msym_bunch
);
953 msym_bunch_index
= 0;
954 new->next
= msym_bunch
;
957 msymbol
= &msym_bunch
->contents
[msym_bunch_index
];
958 MSYMBOL_SET_LANGUAGE (msymbol
, language_auto
,
959 &objfile
->per_bfd
->storage_obstack
);
960 MSYMBOL_SET_NAMES (msymbol
, name
, name_len
, copy_name
, objfile
);
962 SET_MSYMBOL_VALUE_ADDRESS (msymbol
, address
);
963 MSYMBOL_SECTION (msymbol
) = section
;
965 MSYMBOL_TYPE (msymbol
) = ms_type
;
966 MSYMBOL_TARGET_FLAG_1 (msymbol
) = 0;
967 MSYMBOL_TARGET_FLAG_2 (msymbol
) = 0;
968 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
969 as it would also set the has_size flag. */
972 /* The hash pointers must be cleared! If they're not,
973 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
974 msymbol
->hash_next
= NULL
;
975 msymbol
->demangled_hash_next
= NULL
;
977 /* If we already read minimal symbols for this objfile, then don't
978 ever allocate a new one. */
979 if (!objfile
->per_bfd
->minsyms_read
)
982 OBJSTAT (objfile
, n_minsyms
++);
988 struct minimal_symbol
*
989 prim_record_minimal_symbol_and_info (const char *name
, CORE_ADDR address
,
990 enum minimal_symbol_type ms_type
,
992 struct objfile
*objfile
)
994 return prim_record_minimal_symbol_full (name
, strlen (name
), 1,
999 /* Compare two minimal symbols by address and return a signed result based
1000 on unsigned comparisons, so that we sort into unsigned numeric order.
1001 Within groups with the same address, sort by name. */
1004 compare_minimal_symbols (const void *fn1p
, const void *fn2p
)
1006 const struct minimal_symbol
*fn1
;
1007 const struct minimal_symbol
*fn2
;
1009 fn1
= (const struct minimal_symbol
*) fn1p
;
1010 fn2
= (const struct minimal_symbol
*) fn2p
;
1012 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1
) < MSYMBOL_VALUE_RAW_ADDRESS (fn2
))
1014 return (-1); /* addr 1 is less than addr 2. */
1016 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1
) > MSYMBOL_VALUE_RAW_ADDRESS (fn2
))
1018 return (1); /* addr 1 is greater than addr 2. */
1021 /* addrs are equal: sort by name */
1023 const char *name1
= MSYMBOL_LINKAGE_NAME (fn1
);
1024 const char *name2
= MSYMBOL_LINKAGE_NAME (fn2
);
1026 if (name1
&& name2
) /* both have names */
1027 return strcmp (name1
, name2
);
1029 return 1; /* fn1 has no name, so it is "less". */
1030 else if (name1
) /* fn2 has no name, so it is "less". */
1033 return (0); /* Neither has a name, so they're equal. */
1037 /* Discard the currently collected minimal symbols, if any. If we wish
1038 to save them for later use, we must have already copied them somewhere
1039 else before calling this function.
1041 FIXME: We could allocate the minimal symbol bunches on their own
1042 obstack and then simply blow the obstack away when we are done with
1043 it. Is it worth the extra trouble though? */
1046 do_discard_minimal_symbols_cleanup (void *arg
)
1048 struct msym_bunch
*next
;
1050 while (msym_bunch
!= NULL
)
1052 next
= msym_bunch
->next
;
1058 /* See minsyms.h. */
1061 make_cleanup_discard_minimal_symbols (void)
1063 return make_cleanup (do_discard_minimal_symbols_cleanup
, 0);
1068 /* Compact duplicate entries out of a minimal symbol table by walking
1069 through the table and compacting out entries with duplicate addresses
1070 and matching names. Return the number of entries remaining.
1072 On entry, the table resides between msymbol[0] and msymbol[mcount].
1073 On exit, it resides between msymbol[0] and msymbol[result_count].
1075 When files contain multiple sources of symbol information, it is
1076 possible for the minimal symbol table to contain many duplicate entries.
1077 As an example, SVR4 systems use ELF formatted object files, which
1078 usually contain at least two different types of symbol tables (a
1079 standard ELF one and a smaller dynamic linking table), as well as
1080 DWARF debugging information for files compiled with -g.
1082 Without compacting, the minimal symbol table for gdb itself contains
1083 over a 1000 duplicates, about a third of the total table size. Aside
1084 from the potential trap of not noticing that two successive entries
1085 identify the same location, this duplication impacts the time required
1086 to linearly scan the table, which is done in a number of places. So we
1087 just do one linear scan here and toss out the duplicates.
1089 Note that we are not concerned here about recovering the space that
1090 is potentially freed up, because the strings themselves are allocated
1091 on the storage_obstack, and will get automatically freed when the symbol
1092 table is freed. The caller can free up the unused minimal symbols at
1093 the end of the compacted region if their allocation strategy allows it.
1095 Also note we only go up to the next to last entry within the loop
1096 and then copy the last entry explicitly after the loop terminates.
1098 Since the different sources of information for each symbol may
1099 have different levels of "completeness", we may have duplicates
1100 that have one entry with type "mst_unknown" and the other with a
1101 known type. So if the one we are leaving alone has type mst_unknown,
1102 overwrite its type with the type from the one we are compacting out. */
1105 compact_minimal_symbols (struct minimal_symbol
*msymbol
, int mcount
,
1106 struct objfile
*objfile
)
1108 struct minimal_symbol
*copyfrom
;
1109 struct minimal_symbol
*copyto
;
1113 copyfrom
= copyto
= msymbol
;
1114 while (copyfrom
< msymbol
+ mcount
- 1)
1116 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom
)
1117 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom
+ 1))
1118 && MSYMBOL_SECTION (copyfrom
) == MSYMBOL_SECTION (copyfrom
+ 1)
1119 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom
),
1120 MSYMBOL_LINKAGE_NAME ((copyfrom
+ 1))) == 0)
1122 if (MSYMBOL_TYPE ((copyfrom
+ 1)) == mst_unknown
)
1124 MSYMBOL_TYPE ((copyfrom
+ 1)) = MSYMBOL_TYPE (copyfrom
);
1129 *copyto
++ = *copyfrom
++;
1131 *copyto
++ = *copyfrom
++;
1132 mcount
= copyto
- msymbol
;
1137 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1138 after compacting or sorting the table since the entries move around
1139 thus causing the internal minimal_symbol pointers to become jumbled. */
1142 build_minimal_symbol_hash_tables (struct objfile
*objfile
)
1145 struct minimal_symbol
*msym
;
1147 /* Clear the hash tables. */
1148 for (i
= 0; i
< MINIMAL_SYMBOL_HASH_SIZE
; i
++)
1150 objfile
->per_bfd
->msymbol_hash
[i
] = 0;
1151 objfile
->per_bfd
->msymbol_demangled_hash
[i
] = 0;
1154 /* Now, (re)insert the actual entries. */
1155 for ((i
= objfile
->per_bfd
->minimal_symbol_count
,
1156 msym
= objfile
->per_bfd
->msymbols
);
1160 msym
->hash_next
= 0;
1161 add_minsym_to_hash_table (msym
, objfile
->per_bfd
->msymbol_hash
);
1163 msym
->demangled_hash_next
= 0;
1164 if (MSYMBOL_SEARCH_NAME (msym
) != MSYMBOL_LINKAGE_NAME (msym
))
1165 add_minsym_to_demangled_hash_table (msym
,
1166 objfile
->per_bfd
->msymbol_demangled_hash
);
1170 /* Add the minimal symbols in the existing bunches to the objfile's official
1171 minimal symbol table. In most cases there is no minimal symbol table yet
1172 for this objfile, and the existing bunches are used to create one. Once
1173 in a while (for shared libraries for example), we add symbols (e.g. common
1174 symbols) to an existing objfile.
1176 Because of the way minimal symbols are collected, we generally have no way
1177 of knowing what source language applies to any particular minimal symbol.
1178 Specifically, we have no way of knowing if the minimal symbol comes from a
1179 C++ compilation unit or not. So for the sake of supporting cached
1180 demangled C++ names, we have no choice but to try and demangle each new one
1181 that comes in. If the demangling succeeds, then we assume it is a C++
1182 symbol and set the symbol's language and demangled name fields
1183 appropriately. Note that in order to avoid unnecessary demanglings, and
1184 allocating obstack space that subsequently can't be freed for the demangled
1185 names, we mark all newly added symbols with language_auto. After
1186 compaction of the minimal symbols, we go back and scan the entire minimal
1187 symbol table looking for these new symbols. For each new symbol we attempt
1188 to demangle it, and if successful, record it as a language_cplus symbol
1189 and cache the demangled form on the symbol obstack. Symbols which don't
1190 demangle are marked as language_unknown symbols, which inhibits future
1191 attempts to demangle them if we later add more minimal symbols. */
1194 install_minimal_symbols (struct objfile
*objfile
)
1198 struct msym_bunch
*bunch
;
1199 struct minimal_symbol
*msymbols
;
1202 if (objfile
->per_bfd
->minsyms_read
)
1207 if (symtab_create_debug
)
1209 fprintf_unfiltered (gdb_stdlog
,
1210 "Installing %d minimal symbols of objfile %s.\n",
1211 msym_count
, objfile_name (objfile
));
1214 /* Allocate enough space in the obstack, into which we will gather the
1215 bunches of new and existing minimal symbols, sort them, and then
1216 compact out the duplicate entries. Once we have a final table,
1217 we will give back the excess space. */
1219 alloc_count
= msym_count
+ objfile
->per_bfd
->minimal_symbol_count
+ 1;
1220 obstack_blank (&objfile
->per_bfd
->storage_obstack
,
1221 alloc_count
* sizeof (struct minimal_symbol
));
1222 msymbols
= (struct minimal_symbol
*)
1223 obstack_base (&objfile
->per_bfd
->storage_obstack
);
1225 /* Copy in the existing minimal symbols, if there are any. */
1227 if (objfile
->per_bfd
->minimal_symbol_count
)
1228 memcpy ((char *) msymbols
, (char *) objfile
->per_bfd
->msymbols
,
1229 objfile
->per_bfd
->minimal_symbol_count
* sizeof (struct minimal_symbol
));
1231 /* Walk through the list of minimal symbol bunches, adding each symbol
1232 to the new contiguous array of symbols. Note that we start with the
1233 current, possibly partially filled bunch (thus we use the current
1234 msym_bunch_index for the first bunch we copy over), and thereafter
1235 each bunch is full. */
1237 mcount
= objfile
->per_bfd
->minimal_symbol_count
;
1239 for (bunch
= msym_bunch
; bunch
!= NULL
; bunch
= bunch
->next
)
1241 for (bindex
= 0; bindex
< msym_bunch_index
; bindex
++, mcount
++)
1242 msymbols
[mcount
] = bunch
->contents
[bindex
];
1243 msym_bunch_index
= BUNCH_SIZE
;
1246 /* Sort the minimal symbols by address. */
1248 qsort (msymbols
, mcount
, sizeof (struct minimal_symbol
),
1249 compare_minimal_symbols
);
1251 /* Compact out any duplicates, and free up whatever space we are
1254 mcount
= compact_minimal_symbols (msymbols
, mcount
, objfile
);
1256 obstack_blank (&objfile
->per_bfd
->storage_obstack
,
1257 (mcount
+ 1 - alloc_count
) * sizeof (struct minimal_symbol
));
1258 msymbols
= (struct minimal_symbol
*)
1259 obstack_finish (&objfile
->per_bfd
->storage_obstack
);
1261 /* We also terminate the minimal symbol table with a "null symbol",
1262 which is *not* included in the size of the table. This makes it
1263 easier to find the end of the table when we are handed a pointer
1264 to some symbol in the middle of it. Zero out the fields in the
1265 "null symbol" allocated at the end of the array. Note that the
1266 symbol count does *not* include this null symbol, which is why it
1267 is indexed by mcount and not mcount-1. */
1269 memset (&msymbols
[mcount
], 0, sizeof (struct minimal_symbol
));
1271 /* Attach the minimal symbol table to the specified objfile.
1272 The strings themselves are also located in the storage_obstack
1275 objfile
->per_bfd
->minimal_symbol_count
= mcount
;
1276 objfile
->per_bfd
->msymbols
= msymbols
;
1278 /* Now build the hash tables; we can't do this incrementally
1279 at an earlier point since we weren't finished with the obstack
1280 yet. (And if the msymbol obstack gets moved, all the internal
1281 pointers to other msymbols need to be adjusted.) */
1282 build_minimal_symbol_hash_tables (objfile
);
1286 /* See minsyms.h. */
1289 terminate_minimal_symbol_table (struct objfile
*objfile
)
1291 if (! objfile
->per_bfd
->msymbols
)
1292 objfile
->per_bfd
->msymbols
1293 = ((struct minimal_symbol
*)
1294 obstack_alloc (&objfile
->per_bfd
->storage_obstack
,
1295 sizeof (struct minimal_symbol
)));
1298 struct minimal_symbol
*m
1299 = &objfile
->per_bfd
->msymbols
[objfile
->per_bfd
->minimal_symbol_count
];
1301 memset (m
, 0, sizeof (*m
));
1302 /* Don't rely on these enumeration values being 0's. */
1303 MSYMBOL_TYPE (m
) = mst_unknown
;
1304 MSYMBOL_SET_LANGUAGE (m
, language_unknown
,
1305 &objfile
->per_bfd
->storage_obstack
);
1309 /* Check if PC is in a shared library trampoline code stub.
1310 Return minimal symbol for the trampoline entry or NULL if PC is not
1311 in a trampoline code stub. */
1313 static struct minimal_symbol
*
1314 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc
)
1316 struct obj_section
*section
= find_pc_section (pc
);
1317 struct bound_minimal_symbol msymbol
;
1319 if (section
== NULL
)
1321 msymbol
= lookup_minimal_symbol_by_pc_section_1 (pc
, section
, 1);
1323 if (msymbol
.minsym
!= NULL
1324 && MSYMBOL_TYPE (msymbol
.minsym
) == mst_solib_trampoline
)
1325 return msymbol
.minsym
;
1329 /* If PC is in a shared library trampoline code stub, return the
1330 address of the `real' function belonging to the stub.
1331 Return 0 if PC is not in a trampoline code stub or if the real
1332 function is not found in the minimal symbol table.
1334 We may fail to find the right function if a function with the
1335 same name is defined in more than one shared library, but this
1336 is considered bad programming style. We could return 0 if we find
1337 a duplicate function in case this matters someday. */
1340 find_solib_trampoline_target (struct frame_info
*frame
, CORE_ADDR pc
)
1342 struct objfile
*objfile
;
1343 struct minimal_symbol
*msymbol
;
1344 struct minimal_symbol
*tsymbol
= lookup_solib_trampoline_symbol_by_pc (pc
);
1346 if (tsymbol
!= NULL
)
1348 ALL_MSYMBOLS (objfile
, msymbol
)
1350 if ((MSYMBOL_TYPE (msymbol
) == mst_text
1351 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
)
1352 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol
),
1353 MSYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1354 return MSYMBOL_VALUE_ADDRESS (objfile
, msymbol
);
1356 /* Also handle minimal symbols pointing to function descriptors. */
1357 if (MSYMBOL_TYPE (msymbol
) == mst_data
1358 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol
),
1359 MSYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1363 func
= gdbarch_convert_from_func_ptr_addr
1364 (get_objfile_arch (objfile
),
1365 MSYMBOL_VALUE_ADDRESS (objfile
, msymbol
),
1368 /* Ignore data symbols that are not function descriptors. */
1369 if (func
!= MSYMBOL_VALUE_ADDRESS (objfile
, msymbol
))
1377 /* See minsyms.h. */
1380 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym
)
1384 struct obj_section
*obj_section
;
1386 struct minimal_symbol
*msymbol
;
1388 gdb_assert (minsym
.minsym
!= NULL
);
1390 /* If the minimal symbol has a size, use it. Otherwise use the
1391 lesser of the next minimal symbol in the same section, or the end
1392 of the section, as the end of the function. */
1394 if (MSYMBOL_SIZE (minsym
.minsym
) != 0)
1395 return BMSYMBOL_VALUE_ADDRESS (minsym
) + MSYMBOL_SIZE (minsym
.minsym
);
1397 /* Step over other symbols at this same address, and symbols in
1398 other sections, to find the next symbol in this section with a
1399 different address. */
1401 msymbol
= minsym
.minsym
;
1402 section
= MSYMBOL_SECTION (msymbol
);
1403 for (i
= 1; MSYMBOL_LINKAGE_NAME (msymbol
+ i
) != NULL
; i
++)
1405 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol
+ i
)
1406 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol
))
1407 && MSYMBOL_SECTION (msymbol
+ i
) == section
)
1411 obj_section
= MSYMBOL_OBJ_SECTION (minsym
.objfile
, minsym
.minsym
);
1412 if (MSYMBOL_LINKAGE_NAME (msymbol
+ i
) != NULL
1413 && (MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, msymbol
+ i
)
1414 < obj_section_endaddr (obj_section
)))
1415 result
= MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, msymbol
+ i
);
1417 /* We got the start address from the last msymbol in the objfile.
1418 So the end address is the end of the section. */
1419 result
= obj_section_endaddr (obj_section
);