1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2019 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. */
43 #include "filenames.h"
50 #include "cp-support.h"
52 #include "cli/cli-utils.h"
53 #include "common/symbol.h"
55 #include "safe-ctype.h"
60 msymbol_is_function (struct objfile
*objfile
, minimal_symbol
*minsym
,
61 CORE_ADDR
*func_address_p
)
63 CORE_ADDR msym_addr
= MSYMBOL_VALUE_ADDRESS (objfile
, minsym
);
67 case mst_slot_got_plt
:
73 case mst_data_gnu_ifunc
:
75 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
77 = gdbarch_convert_from_func_ptr_addr (gdbarch
, msym_addr
,
78 current_top_target ());
81 if (func_address_p
!= NULL
)
88 if (func_address_p
!= NULL
)
89 *func_address_p
= msym_addr
;
94 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
95 At the end, copy them all into one newly allocated array. */
97 #define BUNCH_SIZE 127
101 struct msym_bunch
*next
;
102 struct minimal_symbol contents
[BUNCH_SIZE
];
108 msymbol_hash_iw (const char *string
)
110 unsigned int hash
= 0;
112 while (*string
&& *string
!= '(')
114 string
= skip_spaces (string
);
115 if (*string
&& *string
!= '(')
117 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
127 msymbol_hash (const char *string
)
129 unsigned int hash
= 0;
131 for (; *string
; ++string
)
132 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
136 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
138 add_minsym_to_hash_table (struct minimal_symbol
*sym
,
139 struct minimal_symbol
**table
)
141 if (sym
->hash_next
== NULL
)
144 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym
)) % MINIMAL_SYMBOL_HASH_SIZE
;
146 sym
->hash_next
= table
[hash
];
151 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
154 add_minsym_to_demangled_hash_table (struct minimal_symbol
*sym
,
155 struct objfile
*objfile
)
157 if (sym
->demangled_hash_next
== NULL
)
159 unsigned int hash
= search_name_hash (MSYMBOL_LANGUAGE (sym
),
160 MSYMBOL_SEARCH_NAME (sym
));
162 objfile
->per_bfd
->demangled_hash_languages
.set (MSYMBOL_LANGUAGE (sym
));
164 struct minimal_symbol
**table
165 = objfile
->per_bfd
->msymbol_demangled_hash
;
166 unsigned int hash_index
= hash
% MINIMAL_SYMBOL_HASH_SIZE
;
167 sym
->demangled_hash_next
= table
[hash_index
];
168 table
[hash_index
] = sym
;
172 /* Worker object for lookup_minimal_symbol. Stores temporary results
173 while walking the symbol tables. */
175 struct found_minimal_symbols
177 /* External symbols are best. */
178 bound_minimal_symbol external_symbol
{};
180 /* File-local symbols are next best. */
181 bound_minimal_symbol file_symbol
{};
183 /* Symbols for shared library trampolines are next best. */
184 bound_minimal_symbol trampoline_symbol
{};
186 /* Called when a symbol name matches. Check if the minsym is a
187 better type than what we had already found, and record it in one
188 of the members fields if so. Returns true if we collected the
189 real symbol, in which case we can stop searching. */
190 bool maybe_collect (const char *sfile
, objfile
*objf
,
191 minimal_symbol
*msymbol
);
194 /* See declaration above. */
197 found_minimal_symbols::maybe_collect (const char *sfile
,
198 struct objfile
*objfile
,
199 minimal_symbol
*msymbol
)
201 switch (MSYMBOL_TYPE (msymbol
))
207 || filename_cmp (msymbol
->filename
, sfile
) == 0)
209 file_symbol
.minsym
= msymbol
;
210 file_symbol
.objfile
= objfile
;
214 case mst_solib_trampoline
:
216 /* If a trampoline symbol is found, we prefer to keep
217 looking for the *real* symbol. If the actual symbol
218 is not found, then we'll use the trampoline
220 if (trampoline_symbol
.minsym
== NULL
)
222 trampoline_symbol
.minsym
= msymbol
;
223 trampoline_symbol
.objfile
= objfile
;
229 external_symbol
.minsym
= msymbol
;
230 external_symbol
.objfile
= objfile
;
231 /* We have the real symbol. No use looking further. */
239 /* Walk the mangled name hash table, and pass each symbol whose name
240 matches LOOKUP_NAME according to NAMECMP to FOUND. */
243 lookup_minimal_symbol_mangled (const char *lookup_name
,
245 struct objfile
*objfile
,
246 struct minimal_symbol
**table
,
248 int (*namecmp
) (const char *, const char *),
249 found_minimal_symbols
&found
)
251 for (minimal_symbol
*msymbol
= table
[hash
];
253 msymbol
= msymbol
->hash_next
)
255 const char *symbol_name
= MSYMBOL_LINKAGE_NAME (msymbol
);
257 if (namecmp (symbol_name
, lookup_name
) == 0
258 && found
.maybe_collect (sfile
, objfile
, msymbol
))
263 /* Walk the demangled name hash table, and pass each symbol whose name
264 matches LOOKUP_NAME according to MATCHER to FOUND. */
267 lookup_minimal_symbol_demangled (const lookup_name_info
&lookup_name
,
269 struct objfile
*objfile
,
270 struct minimal_symbol
**table
,
272 symbol_name_matcher_ftype
*matcher
,
273 found_minimal_symbols
&found
)
275 for (minimal_symbol
*msymbol
= table
[hash
];
277 msymbol
= msymbol
->demangled_hash_next
)
279 const char *symbol_name
= MSYMBOL_SEARCH_NAME (msymbol
);
281 if (matcher (symbol_name
, lookup_name
, NULL
)
282 && found
.maybe_collect (sfile
, objfile
, msymbol
))
287 /* Look through all the current minimal symbol tables and find the
288 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
289 the search to that objfile. If SFILE is non-NULL, the only file-scope
290 symbols considered will be from that source file (global symbols are
291 still preferred). Returns a pointer to the minimal symbol that
292 matches, or NULL if no match is found.
294 Note: One instance where there may be duplicate minimal symbols with
295 the same name is when the symbol tables for a shared library and the
296 symbol tables for an executable contain global symbols with the same
297 names (the dynamic linker deals with the duplication).
299 It's also possible to have minimal symbols with different mangled
300 names, but identical demangled names. For example, the GNU C++ v3
301 ABI requires the generation of two (or perhaps three) copies of
302 constructor functions --- "in-charge", "not-in-charge", and
303 "allocate" copies; destructors may be duplicated as well.
304 Obviously, there must be distinct mangled names for each of these,
305 but the demangled names are all the same: S::S or S::~S. */
307 struct bound_minimal_symbol
308 lookup_minimal_symbol (const char *name
, const char *sfile
,
309 struct objfile
*objf
)
311 found_minimal_symbols found
;
313 unsigned int mangled_hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
316 = (case_sensitivity
== case_sensitive_on
321 sfile
= lbasename (sfile
);
323 lookup_name_info
lookup_name (name
, symbol_name_match_type::FULL
);
325 for (objfile
*objfile
: current_program_space
->objfiles ())
327 if (found
.external_symbol
.minsym
!= NULL
)
330 if (objf
== NULL
|| objf
== objfile
331 || objf
== objfile
->separate_debug_objfile_backlink
)
333 if (symbol_lookup_debug
)
335 fprintf_unfiltered (gdb_stdlog
,
336 "lookup_minimal_symbol (%s, %s, %s)\n",
337 name
, sfile
!= NULL
? sfile
: "NULL",
338 objfile_debug_name (objfile
));
341 /* Do two passes: the first over the ordinary hash table,
342 and the second over the demangled hash table. */
343 lookup_minimal_symbol_mangled (name
, sfile
, objfile
,
344 objfile
->per_bfd
->msymbol_hash
,
345 mangled_hash
, mangled_cmp
, found
);
347 /* If not found, try the demangled hash table. */
348 if (found
.external_symbol
.minsym
== NULL
)
350 /* Once for each language in the demangled hash names
351 table (usually just zero or one languages). */
352 for (unsigned iter
= 0; iter
< nr_languages
; ++iter
)
354 if (!objfile
->per_bfd
->demangled_hash_languages
.test (iter
))
356 enum language lang
= (enum language
) iter
;
359 = (lookup_name
.search_name_hash (lang
)
360 % MINIMAL_SYMBOL_HASH_SIZE
);
362 symbol_name_matcher_ftype
*match
363 = get_symbol_name_matcher (language_def (lang
),
365 struct minimal_symbol
**msymbol_demangled_hash
366 = objfile
->per_bfd
->msymbol_demangled_hash
;
368 lookup_minimal_symbol_demangled (lookup_name
, sfile
, objfile
,
369 msymbol_demangled_hash
,
372 if (found
.external_symbol
.minsym
!= NULL
)
379 /* External symbols are best. */
380 if (found
.external_symbol
.minsym
!= NULL
)
382 if (symbol_lookup_debug
)
384 minimal_symbol
*minsym
= found
.external_symbol
.minsym
;
386 fprintf_unfiltered (gdb_stdlog
,
387 "lookup_minimal_symbol (...) = %s (external)\n",
388 host_address_to_string (minsym
));
390 return found
.external_symbol
;
393 /* File-local symbols are next best. */
394 if (found
.file_symbol
.minsym
!= NULL
)
396 if (symbol_lookup_debug
)
398 minimal_symbol
*minsym
= found
.file_symbol
.minsym
;
400 fprintf_unfiltered (gdb_stdlog
,
401 "lookup_minimal_symbol (...) = %s (file-local)\n",
402 host_address_to_string (minsym
));
404 return found
.file_symbol
;
407 /* Symbols for shared library trampolines are next best. */
408 if (found
.trampoline_symbol
.minsym
!= NULL
)
410 if (symbol_lookup_debug
)
412 minimal_symbol
*minsym
= found
.trampoline_symbol
.minsym
;
414 fprintf_unfiltered (gdb_stdlog
,
415 "lookup_minimal_symbol (...) = %s (trampoline)\n",
416 host_address_to_string (minsym
));
419 return found
.trampoline_symbol
;
423 if (symbol_lookup_debug
)
424 fprintf_unfiltered (gdb_stdlog
, "lookup_minimal_symbol (...) = NULL\n");
430 struct bound_minimal_symbol
431 lookup_bound_minimal_symbol (const char *name
)
433 return lookup_minimal_symbol (name
, NULL
, NULL
);
436 /* See common/symbol.h. */
439 find_minimal_symbol_address (const char *name
, CORE_ADDR
*addr
,
440 struct objfile
*objfile
)
442 struct bound_minimal_symbol sym
443 = lookup_minimal_symbol (name
, NULL
, objfile
);
445 if (sym
.minsym
!= NULL
)
446 *addr
= BMSYMBOL_VALUE_ADDRESS (sym
);
448 return sym
.minsym
== NULL
;
451 /* Get the lookup name form best suitable for linkage name
455 linkage_name_str (const lookup_name_info
&lookup_name
)
457 /* Unlike most languages (including C++), Ada uses the
458 encoded/linkage name as the search name recorded in symbols. So
459 if debugging in Ada mode, prefer the Ada-encoded name. This also
460 makes Ada's verbatim match syntax ("<...>") work, because
461 "lookup_name.name()" includes the "<>"s, while
462 "lookup_name.ada().lookup_name()" is the encoded name with "<>"s
464 if (current_language
->la_language
== language_ada
)
465 return lookup_name
.ada ().lookup_name ().c_str ();
467 return lookup_name
.name ().c_str ();
473 iterate_over_minimal_symbols
474 (struct objfile
*objf
, const lookup_name_info
&lookup_name
,
475 gdb::function_view
<bool (struct minimal_symbol
*)> callback
)
477 /* The first pass is over the ordinary hash table. */
479 const char *name
= linkage_name_str (lookup_name
);
480 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
482 = (case_sensitivity
== case_sensitive_on
486 for (minimal_symbol
*iter
= objf
->per_bfd
->msymbol_hash
[hash
];
488 iter
= iter
->hash_next
)
490 if (mangled_cmp (MSYMBOL_LINKAGE_NAME (iter
), name
) == 0)
496 /* The second pass is over the demangled table. Once for each
497 language in the demangled hash names table (usually just zero or
499 for (unsigned liter
= 0; liter
< nr_languages
; ++liter
)
501 if (!objf
->per_bfd
->demangled_hash_languages
.test (liter
))
504 enum language lang
= (enum language
) liter
;
505 const language_defn
*lang_def
= language_def (lang
);
506 symbol_name_matcher_ftype
*name_match
507 = get_symbol_name_matcher (lang_def
, lookup_name
);
510 = lookup_name
.search_name_hash (lang
) % MINIMAL_SYMBOL_HASH_SIZE
;
511 for (minimal_symbol
*iter
= objf
->per_bfd
->msymbol_demangled_hash
[hash
];
513 iter
= iter
->demangled_hash_next
)
514 if (name_match (MSYMBOL_SEARCH_NAME (iter
), lookup_name
, NULL
))
522 struct bound_minimal_symbol
523 lookup_minimal_symbol_text (const char *name
, struct objfile
*objf
)
525 struct minimal_symbol
*msymbol
;
526 struct bound_minimal_symbol found_symbol
= { NULL
, NULL
};
527 struct bound_minimal_symbol found_file_symbol
= { NULL
, NULL
};
529 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
531 for (objfile
*objfile
: current_program_space
->objfiles ())
533 if (found_symbol
.minsym
!= NULL
)
536 if (objf
== NULL
|| objf
== objfile
537 || objf
== objfile
->separate_debug_objfile_backlink
)
539 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
540 msymbol
!= NULL
&& found_symbol
.minsym
== NULL
;
541 msymbol
= msymbol
->hash_next
)
543 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
544 (MSYMBOL_TYPE (msymbol
) == mst_text
545 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
546 || MSYMBOL_TYPE (msymbol
) == mst_file_text
))
548 switch (MSYMBOL_TYPE (msymbol
))
551 found_file_symbol
.minsym
= msymbol
;
552 found_file_symbol
.objfile
= objfile
;
555 found_symbol
.minsym
= msymbol
;
556 found_symbol
.objfile
= objfile
;
563 /* External symbols are best. */
564 if (found_symbol
.minsym
)
567 /* File-local symbols are next best. */
568 return found_file_symbol
;
573 struct minimal_symbol
*
574 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc
, const char *name
,
575 struct objfile
*objf
)
577 struct minimal_symbol
*msymbol
;
579 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
581 for (objfile
*objfile
: current_program_space
->objfiles ())
583 if (objf
== NULL
|| objf
== objfile
584 || objf
== objfile
->separate_debug_objfile_backlink
)
586 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
588 msymbol
= msymbol
->hash_next
)
590 if (MSYMBOL_VALUE_ADDRESS (objfile
, msymbol
) == pc
591 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0)
602 struct bound_minimal_symbol
603 lookup_minimal_symbol_solib_trampoline (const char *name
,
604 struct objfile
*objf
)
606 struct minimal_symbol
*msymbol
;
607 struct bound_minimal_symbol found_symbol
= { NULL
, NULL
};
609 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
611 for (objfile
*objfile
: current_program_space
->objfiles ())
613 if (objf
== NULL
|| objf
== objfile
614 || objf
== objfile
->separate_debug_objfile_backlink
)
616 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
618 msymbol
= msymbol
->hash_next
)
620 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
621 MSYMBOL_TYPE (msymbol
) == mst_solib_trampoline
)
623 found_symbol
.objfile
= objfile
;
624 found_symbol
.minsym
= msymbol
;
634 /* A helper function that makes *PC section-relative. This searches
635 the sections of OBJFILE and if *PC is in a section, it subtracts
636 the section offset and returns true. Otherwise it returns
640 frob_address (struct objfile
*objfile
, CORE_ADDR
*pc
)
642 struct obj_section
*iter
;
644 ALL_OBJFILE_OSECTIONS (objfile
, iter
)
646 if (*pc
>= obj_section_addr (iter
) && *pc
< obj_section_endaddr (iter
))
648 *pc
-= obj_section_offset (iter
);
656 /* Helper for lookup_minimal_symbol_by_pc_section. Convert a
657 lookup_msym_prefer to a minimal_symbol_type. */
659 static minimal_symbol_type
660 msym_prefer_to_msym_type (lookup_msym_prefer prefer
)
664 case lookup_msym_prefer::TEXT
:
666 case lookup_msym_prefer::TRAMPOLINE
:
667 return mst_solib_trampoline
;
668 case lookup_msym_prefer::GNU_IFUNC
:
669 return mst_text_gnu_ifunc
;
672 /* Assert here instead of in a default switch case above so that
673 -Wswitch warns if a new enumerator is added. */
674 gdb_assert_not_reached ("unhandled lookup_msym_prefer");
677 /* Search through the minimal symbol table for each objfile and find
678 the symbol whose address is the largest address that is still less
679 than or equal to PC, and matches SECTION (which is not NULL).
680 Returns a pointer to the minimal symbol if such a symbol is found,
681 or NULL if PC is not in a suitable range.
682 Note that we need to look through ALL the minimal symbol tables
683 before deciding on the symbol that comes closest to the specified PC.
684 This is because objfiles can overlap, for example objfile A has .text
685 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
688 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
689 there are text and trampoline symbols at the same address.
690 Otherwise prefer mst_text symbols. */
693 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in
, struct obj_section
*section
,
694 lookup_msym_prefer prefer
)
699 struct objfile
*objfile
;
700 struct minimal_symbol
*msymbol
;
701 struct minimal_symbol
*best_symbol
= NULL
;
702 struct objfile
*best_objfile
= NULL
;
703 struct bound_minimal_symbol result
;
707 section
= find_pc_section (pc_in
);
712 minimal_symbol_type want_type
= msym_prefer_to_msym_type (prefer
);
714 /* We can not require the symbol found to be in section, because
715 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
716 symbol - but find_pc_section won't return an absolute section and
717 hence the code below would skip over absolute symbols. We can
718 still take advantage of the call to find_pc_section, though - the
719 object file still must match. In case we have separate debug
720 files, search both the file and its separate debug file. There's
721 no telling which one will have the minimal symbols. */
723 gdb_assert (section
!= NULL
);
725 for (objfile
= section
->objfile
;
727 objfile
= objfile_separate_debug_iterate (section
->objfile
, objfile
))
729 CORE_ADDR pc
= pc_in
;
731 /* If this objfile has a minimal symbol table, go search it
732 using a binary search. */
734 if (objfile
->per_bfd
->minimal_symbol_count
> 0)
736 int best_zero_sized
= -1;
738 msymbol
= objfile
->per_bfd
->msymbols
.get ();
740 hi
= objfile
->per_bfd
->minimal_symbol_count
- 1;
742 /* This code assumes that the minimal symbols are sorted by
743 ascending address values. If the pc value is greater than or
744 equal to the first symbol's address, then some symbol in this
745 minimal symbol table is a suitable candidate for being the
746 "best" symbol. This includes the last real symbol, for cases
747 where the pc value is larger than any address in this vector.
749 By iterating until the address associated with the current
750 hi index (the endpoint of the test interval) is less than
751 or equal to the desired pc value, we accomplish two things:
752 (1) the case where the pc value is larger than any minimal
753 symbol address is trivially solved, (2) the address associated
754 with the hi index is always the one we want when the interation
755 terminates. In essence, we are iterating the test interval
756 down until the pc value is pushed out of it from the high end.
758 Warning: this code is trickier than it would appear at first. */
760 if (frob_address (objfile
, &pc
)
761 && pc
>= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[lo
]))
763 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]) > pc
)
765 /* pc is still strictly less than highest address. */
766 /* Note "new" will always be >= lo. */
767 newobj
= (lo
+ hi
) / 2;
768 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[newobj
]) >= pc
)
779 /* If we have multiple symbols at the same address, we want
780 hi to point to the last one. That way we can find the
781 right symbol if it has an index greater than hi. */
782 while (hi
< objfile
->per_bfd
->minimal_symbol_count
- 1
783 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
784 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
+ 1])))
787 /* Skip various undesirable symbols. */
790 /* Skip any absolute symbols. This is apparently
791 what adb and dbx do, and is needed for the CM-5.
792 There are two known possible problems: (1) on
793 ELF, apparently end, edata, etc. are absolute.
794 Not sure ignoring them here is a big deal, but if
795 we want to use them, the fix would go in
796 elfread.c. (2) I think shared library entry
797 points on the NeXT are absolute. If we want
798 special handling for this it probably should be
799 triggered by a special mst_abs_or_lib or some
802 if (MSYMBOL_TYPE (&msymbol
[hi
]) == mst_abs
)
808 /* If SECTION was specified, skip any symbol from
811 /* Some types of debug info, such as COFF,
812 don't fill the bfd_section member, so don't
813 throw away symbols on those platforms. */
814 && MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]) != NULL
815 && (!matching_obj_sections
816 (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]),
823 /* If we are looking for a trampoline and this is a
824 text symbol, or the other way around, check the
825 preceding symbol too. If they are otherwise
826 identical prefer that one. */
828 && MSYMBOL_TYPE (&msymbol
[hi
]) != want_type
829 && MSYMBOL_TYPE (&msymbol
[hi
- 1]) == want_type
830 && (MSYMBOL_SIZE (&msymbol
[hi
])
831 == MSYMBOL_SIZE (&msymbol
[hi
- 1]))
832 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
833 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1]))
834 && (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
])
835 == MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
- 1])))
841 /* If the minimal symbol has a zero size, save it
842 but keep scanning backwards looking for one with
843 a non-zero size. A zero size may mean that the
844 symbol isn't an object or function (e.g. a
845 label), or it may just mean that the size was not
847 if (MSYMBOL_SIZE (&msymbol
[hi
]) == 0)
849 if (best_zero_sized
== -1)
850 best_zero_sized
= hi
;
855 /* If we are past the end of the current symbol, try
856 the previous symbol if it has a larger overlapping
857 size. This happens on i686-pc-linux-gnu with glibc;
858 the nocancel variants of system calls are inside
859 the cancellable variants, but both have sizes. */
861 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
862 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
863 + MSYMBOL_SIZE (&msymbol
[hi
]))
864 && pc
< (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1])
865 + MSYMBOL_SIZE (&msymbol
[hi
- 1])))
871 /* Otherwise, this symbol must be as good as we're going
876 /* If HI has a zero size, and best_zero_sized is set,
877 then we had two or more zero-sized symbols; prefer
878 the first one we found (which may have a higher
879 address). Also, if we ran off the end, be sure
881 if (best_zero_sized
!= -1
882 && (hi
< 0 || MSYMBOL_SIZE (&msymbol
[hi
]) == 0))
883 hi
= best_zero_sized
;
885 /* If the minimal symbol has a non-zero size, and this
886 PC appears to be outside the symbol's contents, then
887 refuse to use this symbol. If we found a zero-sized
888 symbol with an address greater than this symbol's,
889 use that instead. We assume that if symbols have
890 specified sizes, they do not overlap. */
893 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
894 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
895 + MSYMBOL_SIZE (&msymbol
[hi
])))
897 if (best_zero_sized
!= -1)
898 hi
= best_zero_sized
;
900 /* Go on to the next object file. */
904 /* The minimal symbol indexed by hi now is the best one in this
905 objfile's minimal symbol table. See if it is the best one
909 && ((best_symbol
== NULL
) ||
910 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol
) <
911 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]))))
913 best_symbol
= &msymbol
[hi
];
914 best_objfile
= objfile
;
920 result
.minsym
= best_symbol
;
921 result
.objfile
= best_objfile
;
927 struct bound_minimal_symbol
928 lookup_minimal_symbol_by_pc (CORE_ADDR pc
)
930 return lookup_minimal_symbol_by_pc_section (pc
, NULL
);
933 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
936 in_gnu_ifunc_stub (CORE_ADDR pc
)
938 bound_minimal_symbol msymbol
939 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
940 lookup_msym_prefer::GNU_IFUNC
);
941 return msymbol
.minsym
&& MSYMBOL_TYPE (msymbol
.minsym
) == mst_text_gnu_ifunc
;
944 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
947 stub_gnu_ifunc_resolve_addr (struct gdbarch
*gdbarch
, CORE_ADDR pc
)
949 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
950 "the ELF support compiled in."),
951 paddress (gdbarch
, pc
));
954 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
957 stub_gnu_ifunc_resolve_name (const char *function_name
,
958 CORE_ADDR
*function_address_p
)
960 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
961 "the ELF support compiled in."),
965 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
968 stub_gnu_ifunc_resolver_stop (struct breakpoint
*b
)
970 internal_error (__FILE__
, __LINE__
,
971 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
974 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
977 stub_gnu_ifunc_resolver_return_stop (struct breakpoint
*b
)
979 internal_error (__FILE__
, __LINE__
,
980 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
983 /* See elf_gnu_ifunc_fns for its real implementation. */
985 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns
=
987 stub_gnu_ifunc_resolve_addr
,
988 stub_gnu_ifunc_resolve_name
,
989 stub_gnu_ifunc_resolver_stop
,
990 stub_gnu_ifunc_resolver_return_stop
,
993 /* A placeholder for &elf_gnu_ifunc_fns. */
995 const struct gnu_ifunc_fns
*gnu_ifunc_fns_p
= &stub_gnu_ifunc_fns
;
999 /* Return leading symbol character for a BFD. If BFD is NULL,
1000 return the leading symbol character from the main objfile. */
1003 get_symbol_leading_char (bfd
*abfd
)
1006 return bfd_get_symbol_leading_char (abfd
);
1007 if (symfile_objfile
!= NULL
&& symfile_objfile
->obfd
!= NULL
)
1008 return bfd_get_symbol_leading_char (symfile_objfile
->obfd
);
1012 /* See minsyms.h. */
1014 minimal_symbol_reader::minimal_symbol_reader (struct objfile
*obj
)
1016 m_msym_bunch (NULL
),
1017 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1018 first call to save a minimal symbol to allocate the memory for
1020 m_msym_bunch_index (BUNCH_SIZE
),
1025 /* Discard the currently collected minimal symbols, if any. If we wish
1026 to save them for later use, we must have already copied them somewhere
1027 else before calling this function. */
1029 minimal_symbol_reader::~minimal_symbol_reader ()
1031 struct msym_bunch
*next
;
1033 while (m_msym_bunch
!= NULL
)
1035 next
= m_msym_bunch
->next
;
1036 xfree (m_msym_bunch
);
1037 m_msym_bunch
= next
;
1041 /* See minsyms.h. */
1044 minimal_symbol_reader::record (const char *name
, CORE_ADDR address
,
1045 enum minimal_symbol_type ms_type
)
1052 case mst_text_gnu_ifunc
:
1054 case mst_solib_trampoline
:
1055 section
= SECT_OFF_TEXT (m_objfile
);
1058 case mst_data_gnu_ifunc
:
1060 section
= SECT_OFF_DATA (m_objfile
);
1064 section
= SECT_OFF_BSS (m_objfile
);
1070 record_with_info (name
, address
, ms_type
, section
);
1073 /* Convert an enumerator of type minimal_symbol_type to its string
1077 mst_str (minimal_symbol_type t
)
1079 #define MST_TO_STR(x) case x: return #x;
1082 MST_TO_STR (mst_unknown
);
1083 MST_TO_STR (mst_text
);
1084 MST_TO_STR (mst_text_gnu_ifunc
);
1085 MST_TO_STR (mst_slot_got_plt
);
1086 MST_TO_STR (mst_data
);
1087 MST_TO_STR (mst_bss
);
1088 MST_TO_STR (mst_abs
);
1089 MST_TO_STR (mst_solib_trampoline
);
1090 MST_TO_STR (mst_file_text
);
1091 MST_TO_STR (mst_file_data
);
1092 MST_TO_STR (mst_file_bss
);
1100 /* See minsyms.h. */
1102 struct minimal_symbol
*
1103 minimal_symbol_reader::record_full (const char *name
, int name_len
,
1104 bool copy_name
, CORE_ADDR address
,
1105 enum minimal_symbol_type ms_type
,
1108 struct msym_bunch
*newobj
;
1109 struct minimal_symbol
*msymbol
;
1111 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1112 the minimal symbols, because if there is also another symbol
1113 at the same address (e.g. the first function of the file),
1114 lookup_minimal_symbol_by_pc would have no way of getting the
1116 if (ms_type
== mst_file_text
&& name
[0] == 'g'
1117 && (strcmp (name
, GCC_COMPILED_FLAG_SYMBOL
) == 0
1118 || strcmp (name
, GCC2_COMPILED_FLAG_SYMBOL
) == 0))
1121 /* It's safe to strip the leading char here once, since the name
1122 is also stored stripped in the minimal symbol table. */
1123 if (name
[0] == get_symbol_leading_char (m_objfile
->obfd
))
1129 if (ms_type
== mst_file_text
&& startswith (name
, "__gnu_compiled"))
1132 if (symtab_create_debug
>= 2)
1133 printf_unfiltered ("Recording minsym: %-21s %18s %4d %s\n",
1134 mst_str (ms_type
), hex_string (address
), section
, name
);
1136 if (m_msym_bunch_index
== BUNCH_SIZE
)
1138 newobj
= XCNEW (struct msym_bunch
);
1139 m_msym_bunch_index
= 0;
1140 newobj
->next
= m_msym_bunch
;
1141 m_msym_bunch
= newobj
;
1143 msymbol
= &m_msym_bunch
->contents
[m_msym_bunch_index
];
1144 symbol_set_language (msymbol
, language_auto
,
1145 &m_objfile
->per_bfd
->storage_obstack
);
1146 symbol_set_names (msymbol
, name
, name_len
, copy_name
, m_objfile
->per_bfd
);
1148 SET_MSYMBOL_VALUE_ADDRESS (msymbol
, address
);
1149 MSYMBOL_SECTION (msymbol
) = section
;
1151 MSYMBOL_TYPE (msymbol
) = ms_type
;
1153 /* If we already read minimal symbols for this objfile, then don't
1154 ever allocate a new one. */
1155 if (!m_objfile
->per_bfd
->minsyms_read
)
1157 m_msym_bunch_index
++;
1158 m_objfile
->per_bfd
->n_minsyms
++;
1164 /* Compare two minimal symbols by address and return a signed result based
1165 on unsigned comparisons, so that we sort into unsigned numeric order.
1166 Within groups with the same address, sort by name. */
1169 compare_minimal_symbols (const void *fn1p
, const void *fn2p
)
1171 const struct minimal_symbol
*fn1
;
1172 const struct minimal_symbol
*fn2
;
1174 fn1
= (const struct minimal_symbol
*) fn1p
;
1175 fn2
= (const struct minimal_symbol
*) fn2p
;
1177 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1
) < MSYMBOL_VALUE_RAW_ADDRESS (fn2
))
1179 return (-1); /* addr 1 is less than addr 2. */
1181 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1
) > MSYMBOL_VALUE_RAW_ADDRESS (fn2
))
1183 return (1); /* addr 1 is greater than addr 2. */
1186 /* addrs are equal: sort by name */
1188 const char *name1
= MSYMBOL_LINKAGE_NAME (fn1
);
1189 const char *name2
= MSYMBOL_LINKAGE_NAME (fn2
);
1191 if (name1
&& name2
) /* both have names */
1192 return strcmp (name1
, name2
);
1194 return 1; /* fn1 has no name, so it is "less". */
1195 else if (name1
) /* fn2 has no name, so it is "less". */
1198 return (0); /* Neither has a name, so they're equal. */
1202 /* Compact duplicate entries out of a minimal symbol table by walking
1203 through the table and compacting out entries with duplicate addresses
1204 and matching names. Return the number of entries remaining.
1206 On entry, the table resides between msymbol[0] and msymbol[mcount].
1207 On exit, it resides between msymbol[0] and msymbol[result_count].
1209 When files contain multiple sources of symbol information, it is
1210 possible for the minimal symbol table to contain many duplicate entries.
1211 As an example, SVR4 systems use ELF formatted object files, which
1212 usually contain at least two different types of symbol tables (a
1213 standard ELF one and a smaller dynamic linking table), as well as
1214 DWARF debugging information for files compiled with -g.
1216 Without compacting, the minimal symbol table for gdb itself contains
1217 over a 1000 duplicates, about a third of the total table size. Aside
1218 from the potential trap of not noticing that two successive entries
1219 identify the same location, this duplication impacts the time required
1220 to linearly scan the table, which is done in a number of places. So we
1221 just do one linear scan here and toss out the duplicates.
1223 Since the different sources of information for each symbol may
1224 have different levels of "completeness", we may have duplicates
1225 that have one entry with type "mst_unknown" and the other with a
1226 known type. So if the one we are leaving alone has type mst_unknown,
1227 overwrite its type with the type from the one we are compacting out. */
1230 compact_minimal_symbols (struct minimal_symbol
*msymbol
, int mcount
,
1231 struct objfile
*objfile
)
1233 struct minimal_symbol
*copyfrom
;
1234 struct minimal_symbol
*copyto
;
1238 copyfrom
= copyto
= msymbol
;
1239 while (copyfrom
< msymbol
+ mcount
- 1)
1241 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom
)
1242 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom
+ 1))
1243 && MSYMBOL_SECTION (copyfrom
) == MSYMBOL_SECTION (copyfrom
+ 1)
1244 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom
),
1245 MSYMBOL_LINKAGE_NAME ((copyfrom
+ 1))) == 0)
1247 if (MSYMBOL_TYPE ((copyfrom
+ 1)) == mst_unknown
)
1249 MSYMBOL_TYPE ((copyfrom
+ 1)) = MSYMBOL_TYPE (copyfrom
);
1254 *copyto
++ = *copyfrom
++;
1256 *copyto
++ = *copyfrom
++;
1257 mcount
= copyto
- msymbol
;
1262 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1263 after compacting or sorting the table since the entries move around
1264 thus causing the internal minimal_symbol pointers to become jumbled. */
1267 build_minimal_symbol_hash_tables (struct objfile
*objfile
)
1270 struct minimal_symbol
*msym
;
1272 /* Clear the hash tables. */
1273 for (i
= 0; i
< MINIMAL_SYMBOL_HASH_SIZE
; i
++)
1275 objfile
->per_bfd
->msymbol_hash
[i
] = 0;
1276 objfile
->per_bfd
->msymbol_demangled_hash
[i
] = 0;
1279 /* Now, (re)insert the actual entries. */
1280 for ((i
= objfile
->per_bfd
->minimal_symbol_count
,
1281 msym
= objfile
->per_bfd
->msymbols
.get ());
1285 msym
->hash_next
= 0;
1286 add_minsym_to_hash_table (msym
, objfile
->per_bfd
->msymbol_hash
);
1288 msym
->demangled_hash_next
= 0;
1289 if (MSYMBOL_SEARCH_NAME (msym
) != MSYMBOL_LINKAGE_NAME (msym
))
1290 add_minsym_to_demangled_hash_table (msym
, objfile
);
1294 /* Add the minimal symbols in the existing bunches to the objfile's official
1295 minimal symbol table. In most cases there is no minimal symbol table yet
1296 for this objfile, and the existing bunches are used to create one. Once
1297 in a while (for shared libraries for example), we add symbols (e.g. common
1298 symbols) to an existing objfile. */
1301 minimal_symbol_reader::install ()
1304 struct msym_bunch
*bunch
;
1305 struct minimal_symbol
*msymbols
;
1308 if (m_objfile
->per_bfd
->minsyms_read
)
1311 if (m_msym_count
> 0)
1313 if (symtab_create_debug
)
1315 fprintf_unfiltered (gdb_stdlog
,
1316 "Installing %d minimal symbols of objfile %s.\n",
1317 m_msym_count
, objfile_name (m_objfile
));
1320 /* Allocate enough space, into which we will gather the bunches
1321 of new and existing minimal symbols, sort them, and then
1322 compact out the duplicate entries. Once we have a final
1323 table, we will give back the excess space. */
1325 alloc_count
= m_msym_count
+ m_objfile
->per_bfd
->minimal_symbol_count
;
1326 gdb::unique_xmalloc_ptr
<minimal_symbol
>
1327 msym_holder (XNEWVEC (minimal_symbol
, alloc_count
));
1328 msymbols
= msym_holder
.get ();
1330 /* Copy in the existing minimal symbols, if there are any. */
1332 if (m_objfile
->per_bfd
->minimal_symbol_count
)
1333 memcpy (msymbols
, m_objfile
->per_bfd
->msymbols
.get (),
1334 m_objfile
->per_bfd
->minimal_symbol_count
1335 * sizeof (struct minimal_symbol
));
1337 /* Walk through the list of minimal symbol bunches, adding each symbol
1338 to the new contiguous array of symbols. Note that we start with the
1339 current, possibly partially filled bunch (thus we use the current
1340 msym_bunch_index for the first bunch we copy over), and thereafter
1341 each bunch is full. */
1343 mcount
= m_objfile
->per_bfd
->minimal_symbol_count
;
1345 for (bunch
= m_msym_bunch
; bunch
!= NULL
; bunch
= bunch
->next
)
1347 memcpy (&msymbols
[mcount
], &bunch
->contents
[0],
1348 m_msym_bunch_index
* sizeof (struct minimal_symbol
));
1349 mcount
+= m_msym_bunch_index
;
1350 m_msym_bunch_index
= BUNCH_SIZE
;
1353 /* Sort the minimal symbols by address. */
1355 qsort (msymbols
, mcount
, sizeof (struct minimal_symbol
),
1356 compare_minimal_symbols
);
1358 /* Compact out any duplicates, and free up whatever space we are
1361 mcount
= compact_minimal_symbols (msymbols
, mcount
, m_objfile
);
1362 msym_holder
.reset (XRESIZEVEC (struct minimal_symbol
,
1363 msym_holder
.release (),
1366 /* Attach the minimal symbol table to the specified objfile.
1367 The strings themselves are also located in the storage_obstack
1370 m_objfile
->per_bfd
->minimal_symbol_count
= mcount
;
1371 m_objfile
->per_bfd
->msymbols
= std::move (msym_holder
);
1373 build_minimal_symbol_hash_tables (m_objfile
);
1377 /* Check if PC is in a shared library trampoline code stub.
1378 Return minimal symbol for the trampoline entry or NULL if PC is not
1379 in a trampoline code stub. */
1381 static struct minimal_symbol
*
1382 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc
)
1384 bound_minimal_symbol msymbol
1385 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
1386 lookup_msym_prefer::TRAMPOLINE
);
1388 if (msymbol
.minsym
!= NULL
1389 && MSYMBOL_TYPE (msymbol
.minsym
) == mst_solib_trampoline
)
1390 return msymbol
.minsym
;
1394 /* If PC is in a shared library trampoline code stub, return the
1395 address of the `real' function belonging to the stub.
1396 Return 0 if PC is not in a trampoline code stub or if the real
1397 function is not found in the minimal symbol table.
1399 We may fail to find the right function if a function with the
1400 same name is defined in more than one shared library, but this
1401 is considered bad programming style. We could return 0 if we find
1402 a duplicate function in case this matters someday. */
1405 find_solib_trampoline_target (struct frame_info
*frame
, CORE_ADDR pc
)
1407 struct minimal_symbol
*tsymbol
= lookup_solib_trampoline_symbol_by_pc (pc
);
1409 if (tsymbol
!= NULL
)
1411 for (objfile
*objfile
: current_program_space
->objfiles ())
1413 for (minimal_symbol
*msymbol
: objfile
->msymbols ())
1415 /* Also handle minimal symbols pointing to function
1417 if ((MSYMBOL_TYPE (msymbol
) == mst_text
1418 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
1419 || MSYMBOL_TYPE (msymbol
) == mst_data
1420 || MSYMBOL_TYPE (msymbol
) == mst_data_gnu_ifunc
)
1421 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol
),
1422 MSYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1426 /* Ignore data symbols that are not function
1428 if (msymbol_is_function (objfile
, msymbol
, &func
))
1437 /* See minsyms.h. */
1440 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym
)
1443 struct obj_section
*obj_section
;
1445 struct minimal_symbol
*iter
, *msymbol
;
1447 gdb_assert (minsym
.minsym
!= NULL
);
1449 /* If the minimal symbol has a size, use it. Otherwise use the
1450 lesser of the next minimal symbol in the same section, or the end
1451 of the section, as the end of the function. */
1453 if (MSYMBOL_SIZE (minsym
.minsym
) != 0)
1454 return BMSYMBOL_VALUE_ADDRESS (minsym
) + MSYMBOL_SIZE (minsym
.minsym
);
1456 /* Step over other symbols at this same address, and symbols in
1457 other sections, to find the next symbol in this section with a
1458 different address. */
1460 struct minimal_symbol
*past_the_end
1461 = (minsym
.objfile
->per_bfd
->msymbols
.get ()
1462 + minsym
.objfile
->per_bfd
->minimal_symbol_count
);
1463 msymbol
= minsym
.minsym
;
1464 section
= MSYMBOL_SECTION (msymbol
);
1465 for (iter
= msymbol
+ 1; iter
!= past_the_end
; ++iter
)
1467 if ((MSYMBOL_VALUE_RAW_ADDRESS (iter
)
1468 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol
))
1469 && MSYMBOL_SECTION (iter
) == section
)
1473 obj_section
= MSYMBOL_OBJ_SECTION (minsym
.objfile
, minsym
.minsym
);
1474 if (iter
!= past_the_end
1475 && (MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, iter
)
1476 < obj_section_endaddr (obj_section
)))
1477 result
= MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, iter
);
1479 /* We got the start address from the last msymbol in the objfile.
1480 So the end address is the end of the section. */
1481 result
= obj_section_endaddr (obj_section
);