1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2022 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 "gdbsupport/symbol.h"
55 #include "safe-ctype.h"
56 #include "gdbsupport/parallel-for.h"
63 /* Return true if MINSYM is a cold clone symbol.
64 Recognize f.i. these symbols (mangled/demangled):
67 - _ZL9do_rpo_vnP8functionP8edge_defP11bitmap_headbb.cold.138
68 do_rpo_vn(function*, edge_def*, bitmap_head*, bool, bool) \
72 msymbol_is_cold_clone (minimal_symbol
*minsym
)
74 const char *name
= minsym
->natural_name ();
75 size_t name_len
= strlen (name
);
79 const char *last
= &name
[name_len
- 1];
83 const char *suffix
= " [clone .cold";
84 size_t suffix_len
= strlen (suffix
);
85 const char *found
= strstr (name
, suffix
);
89 const char *start
= &found
[suffix_len
];
97 for (p
= start
+ 1; p
<= last
; ++p
)
99 if (*p
>= '0' && *p
<= '9')
113 msymbol_is_function (struct objfile
*objfile
, minimal_symbol
*minsym
,
114 CORE_ADDR
*func_address_p
)
116 CORE_ADDR msym_addr
= minsym
->value_address (objfile
);
118 switch (minsym
->type ())
120 case mst_slot_got_plt
:
126 case mst_data_gnu_ifunc
:
128 struct gdbarch
*gdbarch
= objfile
->arch ();
129 CORE_ADDR pc
= gdbarch_convert_from_func_ptr_addr
130 (gdbarch
, msym_addr
, current_inferior ()->top_target ());
133 if (func_address_p
!= NULL
)
134 *func_address_p
= pc
;
140 /* Ignore function symbol that is not a function entry. */
141 if (msymbol_is_cold_clone (minsym
))
145 if (func_address_p
!= NULL
)
146 *func_address_p
= msym_addr
;
151 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
152 At the end, copy them all into one newly allocated array. */
154 #define BUNCH_SIZE 127
158 struct msym_bunch
*next
;
159 struct minimal_symbol contents
[BUNCH_SIZE
];
165 msymbol_hash_iw (const char *string
)
167 unsigned int hash
= 0;
169 while (*string
&& *string
!= '(')
171 string
= skip_spaces (string
);
172 if (*string
&& *string
!= '(')
174 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
184 msymbol_hash (const char *string
)
186 unsigned int hash
= 0;
188 for (; *string
; ++string
)
189 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
193 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
195 add_minsym_to_hash_table (struct minimal_symbol
*sym
,
196 struct minimal_symbol
**table
,
197 unsigned int hash_value
)
199 if (sym
->hash_next
== NULL
)
201 unsigned int hash
= hash_value
% MINIMAL_SYMBOL_HASH_SIZE
;
203 sym
->hash_next
= table
[hash
];
208 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
211 add_minsym_to_demangled_hash_table (struct minimal_symbol
*sym
,
212 struct objfile
*objfile
,
213 unsigned int hash_value
)
215 if (sym
->demangled_hash_next
== NULL
)
217 objfile
->per_bfd
->demangled_hash_languages
.set (sym
->language ());
219 struct minimal_symbol
**table
220 = objfile
->per_bfd
->msymbol_demangled_hash
;
221 unsigned int hash_index
= hash_value
% MINIMAL_SYMBOL_HASH_SIZE
;
222 sym
->demangled_hash_next
= table
[hash_index
];
223 table
[hash_index
] = sym
;
227 /* Worker object for lookup_minimal_symbol. Stores temporary results
228 while walking the symbol tables. */
230 struct found_minimal_symbols
232 /* External symbols are best. */
233 bound_minimal_symbol external_symbol
;
235 /* File-local symbols are next best. */
236 bound_minimal_symbol file_symbol
;
238 /* Symbols for shared library trampolines are next best. */
239 bound_minimal_symbol trampoline_symbol
;
241 /* Called when a symbol name matches. Check if the minsym is a
242 better type than what we had already found, and record it in one
243 of the members fields if so. Returns true if we collected the
244 real symbol, in which case we can stop searching. */
245 bool maybe_collect (const char *sfile
, objfile
*objf
,
246 minimal_symbol
*msymbol
);
249 /* See declaration above. */
252 found_minimal_symbols::maybe_collect (const char *sfile
,
253 struct objfile
*objfile
,
254 minimal_symbol
*msymbol
)
256 switch (msymbol
->type ())
262 || filename_cmp (msymbol
->filename
, sfile
) == 0)
264 file_symbol
.minsym
= msymbol
;
265 file_symbol
.objfile
= objfile
;
269 case mst_solib_trampoline
:
271 /* If a trampoline symbol is found, we prefer to keep
272 looking for the *real* symbol. If the actual symbol
273 is not found, then we'll use the trampoline
275 if (trampoline_symbol
.minsym
== NULL
)
277 trampoline_symbol
.minsym
= msymbol
;
278 trampoline_symbol
.objfile
= objfile
;
284 external_symbol
.minsym
= msymbol
;
285 external_symbol
.objfile
= objfile
;
286 /* We have the real symbol. No use looking further. */
294 /* Walk the mangled name hash table, and pass each symbol whose name
295 matches LOOKUP_NAME according to NAMECMP to FOUND. */
298 lookup_minimal_symbol_mangled (const char *lookup_name
,
300 struct objfile
*objfile
,
301 struct minimal_symbol
**table
,
303 int (*namecmp
) (const char *, const char *),
304 found_minimal_symbols
&found
)
306 for (minimal_symbol
*msymbol
= table
[hash
];
308 msymbol
= msymbol
->hash_next
)
310 const char *symbol_name
= msymbol
->linkage_name ();
312 if (namecmp (symbol_name
, lookup_name
) == 0
313 && found
.maybe_collect (sfile
, objfile
, msymbol
))
318 /* Walk the demangled name hash table, and pass each symbol whose name
319 matches LOOKUP_NAME according to MATCHER to FOUND. */
322 lookup_minimal_symbol_demangled (const lookup_name_info
&lookup_name
,
324 struct objfile
*objfile
,
325 struct minimal_symbol
**table
,
327 symbol_name_matcher_ftype
*matcher
,
328 found_minimal_symbols
&found
)
330 for (minimal_symbol
*msymbol
= table
[hash
];
332 msymbol
= msymbol
->demangled_hash_next
)
334 const char *symbol_name
= msymbol
->search_name ();
336 if (matcher (symbol_name
, lookup_name
, NULL
)
337 && found
.maybe_collect (sfile
, objfile
, msymbol
))
342 /* Look through all the current minimal symbol tables and find the
343 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
344 the search to that objfile. If SFILE is non-NULL, the only file-scope
345 symbols considered will be from that source file (global symbols are
346 still preferred). Returns a pointer to the minimal symbol that
347 matches, or NULL if no match is found.
349 Note: One instance where there may be duplicate minimal symbols with
350 the same name is when the symbol tables for a shared library and the
351 symbol tables for an executable contain global symbols with the same
352 names (the dynamic linker deals with the duplication).
354 It's also possible to have minimal symbols with different mangled
355 names, but identical demangled names. For example, the GNU C++ v3
356 ABI requires the generation of two (or perhaps three) copies of
357 constructor functions --- "in-charge", "not-in-charge", and
358 "allocate" copies; destructors may be duplicated as well.
359 Obviously, there must be distinct mangled names for each of these,
360 but the demangled names are all the same: S::S or S::~S. */
362 struct bound_minimal_symbol
363 lookup_minimal_symbol (const char *name
, const char *sfile
,
364 struct objfile
*objf
)
366 found_minimal_symbols found
;
368 unsigned int mangled_hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
371 = (case_sensitivity
== case_sensitive_on
376 sfile
= lbasename (sfile
);
378 lookup_name_info
lookup_name (name
, symbol_name_match_type::FULL
);
380 for (objfile
*objfile
: current_program_space
->objfiles ())
382 if (found
.external_symbol
.minsym
!= NULL
)
385 if (objf
== NULL
|| objf
== objfile
386 || objf
== objfile
->separate_debug_objfile_backlink
)
388 if (symbol_lookup_debug
)
390 gdb_printf (gdb_stdlog
,
391 "lookup_minimal_symbol (%s, %s, %s)\n",
392 name
, sfile
!= NULL
? sfile
: "NULL",
393 objfile_debug_name (objfile
));
396 /* Do two passes: the first over the ordinary hash table,
397 and the second over the demangled hash table. */
398 lookup_minimal_symbol_mangled (name
, sfile
, objfile
,
399 objfile
->per_bfd
->msymbol_hash
,
400 mangled_hash
, mangled_cmp
, found
);
402 /* If not found, try the demangled hash table. */
403 if (found
.external_symbol
.minsym
== NULL
)
405 /* Once for each language in the demangled hash names
406 table (usually just zero or one languages). */
407 for (unsigned iter
= 0; iter
< nr_languages
; ++iter
)
409 if (!objfile
->per_bfd
->demangled_hash_languages
.test (iter
))
411 enum language lang
= (enum language
) iter
;
414 = (lookup_name
.search_name_hash (lang
)
415 % MINIMAL_SYMBOL_HASH_SIZE
);
417 symbol_name_matcher_ftype
*match
418 = language_def (lang
)->get_symbol_name_matcher
420 struct minimal_symbol
**msymbol_demangled_hash
421 = objfile
->per_bfd
->msymbol_demangled_hash
;
423 lookup_minimal_symbol_demangled (lookup_name
, sfile
, objfile
,
424 msymbol_demangled_hash
,
427 if (found
.external_symbol
.minsym
!= NULL
)
434 /* External symbols are best. */
435 if (found
.external_symbol
.minsym
!= NULL
)
437 if (symbol_lookup_debug
)
439 minimal_symbol
*minsym
= found
.external_symbol
.minsym
;
441 gdb_printf (gdb_stdlog
,
442 "lookup_minimal_symbol (...) = %s (external)\n",
443 host_address_to_string (minsym
));
445 return found
.external_symbol
;
448 /* File-local symbols are next best. */
449 if (found
.file_symbol
.minsym
!= NULL
)
451 if (symbol_lookup_debug
)
453 minimal_symbol
*minsym
= found
.file_symbol
.minsym
;
455 gdb_printf (gdb_stdlog
,
456 "lookup_minimal_symbol (...) = %s (file-local)\n",
457 host_address_to_string (minsym
));
459 return found
.file_symbol
;
462 /* Symbols for shared library trampolines are next best. */
463 if (found
.trampoline_symbol
.minsym
!= NULL
)
465 if (symbol_lookup_debug
)
467 minimal_symbol
*minsym
= found
.trampoline_symbol
.minsym
;
469 gdb_printf (gdb_stdlog
,
470 "lookup_minimal_symbol (...) = %s (trampoline)\n",
471 host_address_to_string (minsym
));
474 return found
.trampoline_symbol
;
478 if (symbol_lookup_debug
)
479 gdb_printf (gdb_stdlog
, "lookup_minimal_symbol (...) = NULL\n");
485 struct bound_minimal_symbol
486 lookup_bound_minimal_symbol (const char *name
)
488 return lookup_minimal_symbol (name
, NULL
, NULL
);
491 /* See gdbsupport/symbol.h. */
494 find_minimal_symbol_address (const char *name
, CORE_ADDR
*addr
,
495 struct objfile
*objfile
)
497 struct bound_minimal_symbol sym
498 = lookup_minimal_symbol (name
, NULL
, objfile
);
500 if (sym
.minsym
!= NULL
)
501 *addr
= sym
.value_address ();
503 return sym
.minsym
== NULL
;
506 /* Get the lookup name form best suitable for linkage name
510 linkage_name_str (const lookup_name_info
&lookup_name
)
512 /* Unlike most languages (including C++), Ada uses the
513 encoded/linkage name as the search name recorded in symbols. So
514 if debugging in Ada mode, prefer the Ada-encoded name. This also
515 makes Ada's verbatim match syntax ("<...>") work, because
516 "lookup_name.name()" includes the "<>"s, while
517 "lookup_name.ada().lookup_name()" is the encoded name with "<>"s
519 if (current_language
->la_language
== language_ada
)
520 return lookup_name
.ada ().lookup_name ().c_str ();
522 return lookup_name
.c_str ();
528 iterate_over_minimal_symbols
529 (struct objfile
*objf
, const lookup_name_info
&lookup_name
,
530 gdb::function_view
<bool (struct minimal_symbol
*)> callback
)
532 /* The first pass is over the ordinary hash table. */
534 const char *name
= linkage_name_str (lookup_name
);
535 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
537 = (case_sensitivity
== case_sensitive_on
541 for (minimal_symbol
*iter
= objf
->per_bfd
->msymbol_hash
[hash
];
543 iter
= iter
->hash_next
)
545 if (mangled_cmp (iter
->linkage_name (), name
) == 0)
551 /* The second pass is over the demangled table. Once for each
552 language in the demangled hash names table (usually just zero or
554 for (unsigned liter
= 0; liter
< nr_languages
; ++liter
)
556 if (!objf
->per_bfd
->demangled_hash_languages
.test (liter
))
559 enum language lang
= (enum language
) liter
;
560 const language_defn
*lang_def
= language_def (lang
);
561 symbol_name_matcher_ftype
*name_match
562 = lang_def
->get_symbol_name_matcher (lookup_name
);
565 = lookup_name
.search_name_hash (lang
) % MINIMAL_SYMBOL_HASH_SIZE
;
566 for (minimal_symbol
*iter
= objf
->per_bfd
->msymbol_demangled_hash
[hash
];
568 iter
= iter
->demangled_hash_next
)
569 if (name_match (iter
->search_name (), lookup_name
, NULL
))
578 lookup_minimal_symbol_linkage (const char *name
, struct objfile
*objf
)
580 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
582 for (objfile
*objfile
: objf
->separate_debug_objfiles ())
584 for (minimal_symbol
*msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
586 msymbol
= msymbol
->hash_next
)
588 if (strcmp (msymbol
->linkage_name (), name
) == 0
589 && (msymbol
->type () == mst_data
590 || msymbol
->type () == mst_bss
))
591 return {msymbol
, objfile
};
600 struct bound_minimal_symbol
601 lookup_minimal_symbol_text (const char *name
, struct objfile
*objf
)
603 struct minimal_symbol
*msymbol
;
604 struct bound_minimal_symbol found_symbol
;
605 struct bound_minimal_symbol found_file_symbol
;
607 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
609 for (objfile
*objfile
: current_program_space
->objfiles ())
611 if (found_symbol
.minsym
!= NULL
)
614 if (objf
== NULL
|| objf
== objfile
615 || objf
== objfile
->separate_debug_objfile_backlink
)
617 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
618 msymbol
!= NULL
&& found_symbol
.minsym
== NULL
;
619 msymbol
= msymbol
->hash_next
)
621 if (strcmp (msymbol
->linkage_name (), name
) == 0 &&
622 (msymbol
->type () == mst_text
623 || msymbol
->type () == mst_text_gnu_ifunc
624 || msymbol
->type () == mst_file_text
))
626 switch (msymbol
->type ())
629 found_file_symbol
.minsym
= msymbol
;
630 found_file_symbol
.objfile
= objfile
;
633 found_symbol
.minsym
= msymbol
;
634 found_symbol
.objfile
= objfile
;
641 /* External symbols are best. */
642 if (found_symbol
.minsym
)
645 /* File-local symbols are next best. */
646 return found_file_symbol
;
651 struct minimal_symbol
*
652 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc
, const char *name
,
653 struct objfile
*objf
)
655 struct minimal_symbol
*msymbol
;
657 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
659 for (objfile
*objfile
: current_program_space
->objfiles ())
661 if (objf
== NULL
|| objf
== objfile
662 || objf
== objfile
->separate_debug_objfile_backlink
)
664 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
666 msymbol
= msymbol
->hash_next
)
668 if (msymbol
->value_address (objfile
) == pc
669 && strcmp (msymbol
->linkage_name (), name
) == 0)
678 /* A helper function that makes *PC section-relative. This searches
679 the sections of OBJFILE and if *PC is in a section, it subtracts
680 the section offset and returns true. Otherwise it returns
684 frob_address (struct objfile
*objfile
, CORE_ADDR
*pc
)
686 struct obj_section
*iter
;
688 ALL_OBJFILE_OSECTIONS (objfile
, iter
)
690 if (*pc
>= iter
->addr () && *pc
< iter
->endaddr ())
692 *pc
-= iter
->offset ();
700 /* Helper for lookup_minimal_symbol_by_pc_section. Convert a
701 lookup_msym_prefer to a minimal_symbol_type. */
703 static minimal_symbol_type
704 msym_prefer_to_msym_type (lookup_msym_prefer prefer
)
708 case lookup_msym_prefer::TEXT
:
710 case lookup_msym_prefer::TRAMPOLINE
:
711 return mst_solib_trampoline
;
712 case lookup_msym_prefer::GNU_IFUNC
:
713 return mst_text_gnu_ifunc
;
716 /* Assert here instead of in a default switch case above so that
717 -Wswitch warns if a new enumerator is added. */
718 gdb_assert_not_reached ("unhandled lookup_msym_prefer");
723 Note that we need to look through ALL the minimal symbol tables
724 before deciding on the symbol that comes closest to the specified PC.
725 This is because objfiles can overlap, for example objfile A has .text
726 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
730 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in
, struct obj_section
*section
,
731 lookup_msym_prefer prefer
,
732 bound_minimal_symbol
*previous
)
737 struct minimal_symbol
*msymbol
;
738 struct minimal_symbol
*best_symbol
= NULL
;
739 struct objfile
*best_objfile
= NULL
;
740 struct bound_minimal_symbol result
;
742 if (previous
!= nullptr)
744 previous
->minsym
= nullptr;
745 previous
->objfile
= nullptr;
750 section
= find_pc_section (pc_in
);
755 minimal_symbol_type want_type
= msym_prefer_to_msym_type (prefer
);
757 /* We can not require the symbol found to be in section, because
758 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
759 symbol - but find_pc_section won't return an absolute section and
760 hence the code below would skip over absolute symbols. We can
761 still take advantage of the call to find_pc_section, though - the
762 object file still must match. In case we have separate debug
763 files, search both the file and its separate debug file. There's
764 no telling which one will have the minimal symbols. */
766 gdb_assert (section
!= NULL
);
768 for (objfile
*objfile
: section
->objfile
->separate_debug_objfiles ())
770 CORE_ADDR pc
= pc_in
;
772 /* If this objfile has a minimal symbol table, go search it
773 using a binary search. */
775 if (objfile
->per_bfd
->minimal_symbol_count
> 0)
777 int best_zero_sized
= -1;
779 msymbol
= objfile
->per_bfd
->msymbols
.get ();
781 hi
= objfile
->per_bfd
->minimal_symbol_count
- 1;
783 /* This code assumes that the minimal symbols are sorted by
784 ascending address values. If the pc value is greater than or
785 equal to the first symbol's address, then some symbol in this
786 minimal symbol table is a suitable candidate for being the
787 "best" symbol. This includes the last real symbol, for cases
788 where the pc value is larger than any address in this vector.
790 By iterating until the address associated with the current
791 hi index (the endpoint of the test interval) is less than
792 or equal to the desired pc value, we accomplish two things:
793 (1) the case where the pc value is larger than any minimal
794 symbol address is trivially solved, (2) the address associated
795 with the hi index is always the one we want when the iteration
796 terminates. In essence, we are iterating the test interval
797 down until the pc value is pushed out of it from the high end.
799 Warning: this code is trickier than it would appear at first. */
801 if (frob_address (objfile
, &pc
)
802 && pc
>= msymbol
[lo
].value_raw_address ())
804 while (msymbol
[hi
].value_raw_address () > pc
)
806 /* pc is still strictly less than highest address. */
807 /* Note "new" will always be >= lo. */
808 newobj
= (lo
+ hi
) / 2;
809 if ((msymbol
[newobj
].value_raw_address () >= pc
)
820 /* If we have multiple symbols at the same address, we want
821 hi to point to the last one. That way we can find the
822 right symbol if it has an index greater than hi. */
823 while (hi
< objfile
->per_bfd
->minimal_symbol_count
- 1
824 && (msymbol
[hi
].value_raw_address ()
825 == msymbol
[hi
+ 1].value_raw_address ()))
828 /* Skip various undesirable symbols. */
831 /* Skip any absolute symbols. This is apparently
832 what adb and dbx do, and is needed for the CM-5.
833 There are two known possible problems: (1) on
834 ELF, apparently end, edata, etc. are absolute.
835 Not sure ignoring them here is a big deal, but if
836 we want to use them, the fix would go in
837 elfread.c. (2) I think shared library entry
838 points on the NeXT are absolute. If we want
839 special handling for this it probably should be
840 triggered by a special mst_abs_or_lib or some
843 if (msymbol
[hi
].type () == mst_abs
)
849 /* If SECTION was specified, skip any symbol from
852 /* Some types of debug info, such as COFF,
853 don't fill the bfd_section member, so don't
854 throw away symbols on those platforms. */
855 && msymbol
[hi
].obj_section (objfile
) != nullptr
856 && (!matching_obj_sections
857 (msymbol
[hi
].obj_section (objfile
),
864 /* If we are looking for a trampoline and this is a
865 text symbol, or the other way around, check the
866 preceding symbol too. If they are otherwise
867 identical prefer that one. */
869 && msymbol
[hi
].type () != want_type
870 && msymbol
[hi
- 1].type () == want_type
871 && (msymbol
[hi
].size () == msymbol
[hi
- 1].size ())
872 && (msymbol
[hi
].value_raw_address ()
873 == msymbol
[hi
- 1].value_raw_address ())
874 && (msymbol
[hi
].obj_section (objfile
)
875 == msymbol
[hi
- 1].obj_section (objfile
)))
881 /* If the minimal symbol has a zero size, save it
882 but keep scanning backwards looking for one with
883 a non-zero size. A zero size may mean that the
884 symbol isn't an object or function (e.g. a
885 label), or it may just mean that the size was not
887 if (msymbol
[hi
].size () == 0)
889 if (best_zero_sized
== -1)
890 best_zero_sized
= hi
;
895 /* If we are past the end of the current symbol, try
896 the previous symbol if it has a larger overlapping
897 size. This happens on i686-pc-linux-gnu with glibc;
898 the nocancel variants of system calls are inside
899 the cancellable variants, but both have sizes. */
901 && msymbol
[hi
].size () != 0
902 && pc
>= (msymbol
[hi
].value_raw_address ()
903 + msymbol
[hi
].size ())
904 && pc
< (msymbol
[hi
- 1].value_raw_address ()
905 + msymbol
[hi
- 1].size ()))
911 /* Otherwise, this symbol must be as good as we're going
916 /* If HI has a zero size, and best_zero_sized is set,
917 then we had two or more zero-sized symbols; prefer
918 the first one we found (which may have a higher
919 address). Also, if we ran off the end, be sure
921 if (best_zero_sized
!= -1
922 && (hi
< 0 || msymbol
[hi
].size () == 0))
923 hi
= best_zero_sized
;
925 /* If the minimal symbol has a non-zero size, and this
926 PC appears to be outside the symbol's contents, then
927 refuse to use this symbol. If we found a zero-sized
928 symbol with an address greater than this symbol's,
929 use that instead. We assume that if symbols have
930 specified sizes, they do not overlap. */
933 && msymbol
[hi
].size () != 0
934 && pc
>= (msymbol
[hi
].value_raw_address ()
935 + msymbol
[hi
].size ()))
937 if (best_zero_sized
!= -1)
938 hi
= best_zero_sized
;
941 /* If needed record this symbol as the closest
943 if (previous
!= nullptr)
945 if (previous
->minsym
== nullptr
946 || (msymbol
[hi
].value_raw_address ()
947 > previous
->minsym
->value_raw_address ()))
949 previous
->minsym
= &msymbol
[hi
];
950 previous
->objfile
= objfile
;
953 /* Go on to the next object file. */
958 /* The minimal symbol indexed by hi now is the best one in this
959 objfile's minimal symbol table. See if it is the best one
963 && ((best_symbol
== NULL
) ||
964 (best_symbol
->value_raw_address () <
965 msymbol
[hi
].value_raw_address ())))
967 best_symbol
= &msymbol
[hi
];
968 best_objfile
= objfile
;
974 result
.minsym
= best_symbol
;
975 result
.objfile
= best_objfile
;
981 struct bound_minimal_symbol
982 lookup_minimal_symbol_by_pc (CORE_ADDR pc
)
984 return lookup_minimal_symbol_by_pc_section (pc
, NULL
);
987 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
990 in_gnu_ifunc_stub (CORE_ADDR pc
)
992 bound_minimal_symbol msymbol
993 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
994 lookup_msym_prefer::GNU_IFUNC
);
995 return msymbol
.minsym
&& msymbol
.minsym
->type () == mst_text_gnu_ifunc
;
998 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
1001 stub_gnu_ifunc_resolve_addr (struct gdbarch
*gdbarch
, CORE_ADDR pc
)
1003 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
1004 "the ELF support compiled in."),
1005 paddress (gdbarch
, pc
));
1008 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
1011 stub_gnu_ifunc_resolve_name (const char *function_name
,
1012 CORE_ADDR
*function_address_p
)
1014 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
1015 "the ELF support compiled in."),
1019 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
1022 stub_gnu_ifunc_resolver_stop (code_breakpoint
*b
)
1024 internal_error (_("elf_gnu_ifunc_resolver_stop cannot be reached."));
1027 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
1030 stub_gnu_ifunc_resolver_return_stop (code_breakpoint
*b
)
1032 internal_error (_("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
1035 /* See elf_gnu_ifunc_fns for its real implementation. */
1037 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns
=
1039 stub_gnu_ifunc_resolve_addr
,
1040 stub_gnu_ifunc_resolve_name
,
1041 stub_gnu_ifunc_resolver_stop
,
1042 stub_gnu_ifunc_resolver_return_stop
,
1045 /* A placeholder for &elf_gnu_ifunc_fns. */
1047 const struct gnu_ifunc_fns
*gnu_ifunc_fns_p
= &stub_gnu_ifunc_fns
;
1051 /* Return leading symbol character for a BFD. If BFD is NULL,
1052 return the leading symbol character from the main objfile. */
1055 get_symbol_leading_char (bfd
*abfd
)
1058 return bfd_get_symbol_leading_char (abfd
);
1059 if (current_program_space
->symfile_object_file
!= NULL
)
1061 objfile
*objf
= current_program_space
->symfile_object_file
;
1062 if (objf
->obfd
!= NULL
)
1063 return bfd_get_symbol_leading_char (objf
->obfd
.get ());
1068 /* See minsyms.h. */
1070 minimal_symbol_reader::minimal_symbol_reader (struct objfile
*obj
)
1072 m_msym_bunch (NULL
),
1073 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1074 first call to save a minimal symbol to allocate the memory for
1076 m_msym_bunch_index (BUNCH_SIZE
),
1081 /* Discard the currently collected minimal symbols, if any. If we wish
1082 to save them for later use, we must have already copied them somewhere
1083 else before calling this function. */
1085 minimal_symbol_reader::~minimal_symbol_reader ()
1087 struct msym_bunch
*next
;
1089 while (m_msym_bunch
!= NULL
)
1091 next
= m_msym_bunch
->next
;
1092 xfree (m_msym_bunch
);
1093 m_msym_bunch
= next
;
1097 /* See minsyms.h. */
1100 minimal_symbol_reader::record (const char *name
, CORE_ADDR address
,
1101 enum minimal_symbol_type ms_type
)
1108 case mst_text_gnu_ifunc
:
1110 case mst_solib_trampoline
:
1111 section
= SECT_OFF_TEXT (m_objfile
);
1114 case mst_data_gnu_ifunc
:
1116 section
= SECT_OFF_DATA (m_objfile
);
1120 section
= SECT_OFF_BSS (m_objfile
);
1126 record_with_info (name
, address
, ms_type
, section
);
1129 /* Convert an enumerator of type minimal_symbol_type to its string
1133 mst_str (minimal_symbol_type t
)
1135 #define MST_TO_STR(x) case x: return #x;
1138 MST_TO_STR (mst_unknown
);
1139 MST_TO_STR (mst_text
);
1140 MST_TO_STR (mst_text_gnu_ifunc
);
1141 MST_TO_STR (mst_slot_got_plt
);
1142 MST_TO_STR (mst_data
);
1143 MST_TO_STR (mst_bss
);
1144 MST_TO_STR (mst_abs
);
1145 MST_TO_STR (mst_solib_trampoline
);
1146 MST_TO_STR (mst_file_text
);
1147 MST_TO_STR (mst_file_data
);
1148 MST_TO_STR (mst_file_bss
);
1156 /* See minsyms.h. */
1158 struct minimal_symbol
*
1159 minimal_symbol_reader::record_full (gdb::string_view name
,
1160 bool copy_name
, CORE_ADDR address
,
1161 enum minimal_symbol_type ms_type
,
1164 struct msym_bunch
*newobj
;
1165 struct minimal_symbol
*msymbol
;
1167 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1168 the minimal symbols, because if there is also another symbol
1169 at the same address (e.g. the first function of the file),
1170 lookup_minimal_symbol_by_pc would have no way of getting the
1172 if (ms_type
== mst_file_text
&& name
[0] == 'g'
1173 && (name
== GCC_COMPILED_FLAG_SYMBOL
1174 || name
== GCC2_COMPILED_FLAG_SYMBOL
))
1177 /* It's safe to strip the leading char here once, since the name
1178 is also stored stripped in the minimal symbol table. */
1179 if (name
[0] == get_symbol_leading_char (m_objfile
->obfd
.get ()))
1180 name
= name
.substr (1);
1182 if (ms_type
== mst_file_text
&& startswith (name
, "__gnu_compiled"))
1185 symtab_create_debug_printf_v ("recording minsym: %-21s %18s %4d %.*s",
1186 mst_str (ms_type
), hex_string (address
), section
,
1187 (int) name
.size (), name
.data ());
1189 if (m_msym_bunch_index
== BUNCH_SIZE
)
1191 newobj
= XCNEW (struct msym_bunch
);
1192 m_msym_bunch_index
= 0;
1193 newobj
->next
= m_msym_bunch
;
1194 m_msym_bunch
= newobj
;
1196 msymbol
= &m_msym_bunch
->contents
[m_msym_bunch_index
];
1197 msymbol
->set_language (language_auto
,
1198 &m_objfile
->per_bfd
->storage_obstack
);
1201 msymbol
->m_name
= obstack_strndup (&m_objfile
->per_bfd
->storage_obstack
,
1202 name
.data (), name
.size ());
1204 msymbol
->m_name
= name
.data ();
1206 msymbol
->set_value_address (address
);
1207 msymbol
->set_section_index (section
);
1209 msymbol
->set_type (ms_type
);
1211 /* If we already read minimal symbols for this objfile, then don't
1212 ever allocate a new one. */
1213 if (!m_objfile
->per_bfd
->minsyms_read
)
1215 m_msym_bunch_index
++;
1216 m_objfile
->per_bfd
->n_minsyms
++;
1222 /* Compare two minimal symbols by address and return true if FN1's address
1223 is less than FN2's, so that we sort into unsigned numeric order.
1224 Within groups with the same address, sort by name. */
1227 minimal_symbol_is_less_than (const minimal_symbol
&fn1
,
1228 const minimal_symbol
&fn2
)
1230 if ((&fn1
)->value_raw_address () < (&fn2
)->value_raw_address ())
1232 return true; /* addr 1 is less than addr 2. */
1234 else if ((&fn1
)->value_raw_address () > (&fn2
)->value_raw_address ())
1236 return false; /* addr 1 is greater than addr 2. */
1239 /* addrs are equal: sort by name */
1241 const char *name1
= fn1
.linkage_name ();
1242 const char *name2
= fn2
.linkage_name ();
1244 if (name1
&& name2
) /* both have names */
1245 return strcmp (name1
, name2
) < 0;
1247 return true; /* fn1 has no name, so it is "less". */
1248 else if (name1
) /* fn2 has no name, so it is "less". */
1251 return false; /* Neither has a name, so they're equal. */
1255 /* Compact duplicate entries out of a minimal symbol table by walking
1256 through the table and compacting out entries with duplicate addresses
1257 and matching names. Return the number of entries remaining.
1259 On entry, the table resides between msymbol[0] and msymbol[mcount].
1260 On exit, it resides between msymbol[0] and msymbol[result_count].
1262 When files contain multiple sources of symbol information, it is
1263 possible for the minimal symbol table to contain many duplicate entries.
1264 As an example, SVR4 systems use ELF formatted object files, which
1265 usually contain at least two different types of symbol tables (a
1266 standard ELF one and a smaller dynamic linking table), as well as
1267 DWARF debugging information for files compiled with -g.
1269 Without compacting, the minimal symbol table for gdb itself contains
1270 over a 1000 duplicates, about a third of the total table size. Aside
1271 from the potential trap of not noticing that two successive entries
1272 identify the same location, this duplication impacts the time required
1273 to linearly scan the table, which is done in a number of places. So we
1274 just do one linear scan here and toss out the duplicates.
1276 Since the different sources of information for each symbol may
1277 have different levels of "completeness", we may have duplicates
1278 that have one entry with type "mst_unknown" and the other with a
1279 known type. So if the one we are leaving alone has type mst_unknown,
1280 overwrite its type with the type from the one we are compacting out. */
1283 compact_minimal_symbols (struct minimal_symbol
*msymbol
, int mcount
,
1284 struct objfile
*objfile
)
1286 struct minimal_symbol
*copyfrom
;
1287 struct minimal_symbol
*copyto
;
1291 copyfrom
= copyto
= msymbol
;
1292 while (copyfrom
< msymbol
+ mcount
- 1)
1294 if (copyfrom
->value_raw_address ()
1295 == (copyfrom
+ 1)->value_raw_address ()
1296 && (copyfrom
->section_index ()
1297 == (copyfrom
+ 1)->section_index ())
1298 && strcmp (copyfrom
->linkage_name (),
1299 (copyfrom
+ 1)->linkage_name ()) == 0)
1301 if ((copyfrom
+ 1)->type () == mst_unknown
)
1302 (copyfrom
+ 1)->set_type (copyfrom
->type ());
1307 *copyto
++ = *copyfrom
++;
1309 *copyto
++ = *copyfrom
++;
1310 mcount
= copyto
- msymbol
;
1316 clear_minimal_symbol_hash_tables (struct objfile
*objfile
)
1318 for (size_t i
= 0; i
< MINIMAL_SYMBOL_HASH_SIZE
; i
++)
1320 objfile
->per_bfd
->msymbol_hash
[i
] = 0;
1321 objfile
->per_bfd
->msymbol_demangled_hash
[i
] = 0;
1325 /* This struct is used to store values we compute for msymbols on the
1326 background threads but don't need to keep around long term. */
1327 struct computed_hash_values
1329 /* Length of the linkage_name of the symbol. */
1331 /* Hash code (using fast_hash) of the linkage_name. */
1332 hashval_t mangled_name_hash
;
1333 /* The msymbol_hash of the linkage_name. */
1334 unsigned int minsym_hash
;
1335 /* The msymbol_hash of the search_name. */
1336 unsigned int minsym_demangled_hash
;
1339 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1340 after compacting or sorting the table since the entries move around
1341 thus causing the internal minimal_symbol pointers to become jumbled. */
1344 build_minimal_symbol_hash_tables
1345 (struct objfile
*objfile
,
1346 const std::vector
<computed_hash_values
>& hash_values
)
1349 struct minimal_symbol
*msym
;
1351 /* (Re)insert the actual entries. */
1352 int mcount
= objfile
->per_bfd
->minimal_symbol_count
;
1354 msym
= objfile
->per_bfd
->msymbols
.get ());
1358 msym
->hash_next
= 0;
1359 add_minsym_to_hash_table (msym
, objfile
->per_bfd
->msymbol_hash
,
1360 hash_values
[i
].minsym_hash
);
1362 msym
->demangled_hash_next
= 0;
1363 if (msym
->search_name () != msym
->linkage_name ())
1364 add_minsym_to_demangled_hash_table
1365 (msym
, objfile
, hash_values
[i
].minsym_demangled_hash
);
1369 /* Add the minimal symbols in the existing bunches to the objfile's official
1370 minimal symbol table. In most cases there is no minimal symbol table yet
1371 for this objfile, and the existing bunches are used to create one. Once
1372 in a while (for shared libraries for example), we add symbols (e.g. common
1373 symbols) to an existing objfile. */
1376 minimal_symbol_reader::install ()
1379 struct msym_bunch
*bunch
;
1380 struct minimal_symbol
*msymbols
;
1383 if (m_objfile
->per_bfd
->minsyms_read
)
1386 if (m_msym_count
> 0)
1388 symtab_create_debug_printf ("installing %d minimal symbols of objfile %s",
1389 m_msym_count
, objfile_name (m_objfile
));
1391 /* Allocate enough space, into which we will gather the bunches
1392 of new and existing minimal symbols, sort them, and then
1393 compact out the duplicate entries. Once we have a final
1394 table, we will give back the excess space. */
1396 alloc_count
= m_msym_count
+ m_objfile
->per_bfd
->minimal_symbol_count
;
1397 gdb::unique_xmalloc_ptr
<minimal_symbol
>
1398 msym_holder (XNEWVEC (minimal_symbol
, alloc_count
));
1399 msymbols
= msym_holder
.get ();
1401 /* Copy in the existing minimal symbols, if there are any. */
1403 if (m_objfile
->per_bfd
->minimal_symbol_count
)
1404 memcpy (msymbols
, m_objfile
->per_bfd
->msymbols
.get (),
1405 m_objfile
->per_bfd
->minimal_symbol_count
1406 * sizeof (struct minimal_symbol
));
1408 /* Walk through the list of minimal symbol bunches, adding each symbol
1409 to the new contiguous array of symbols. Note that we start with the
1410 current, possibly partially filled bunch (thus we use the current
1411 msym_bunch_index for the first bunch we copy over), and thereafter
1412 each bunch is full. */
1414 mcount
= m_objfile
->per_bfd
->minimal_symbol_count
;
1416 for (bunch
= m_msym_bunch
; bunch
!= NULL
; bunch
= bunch
->next
)
1418 memcpy (&msymbols
[mcount
], &bunch
->contents
[0],
1419 m_msym_bunch_index
* sizeof (struct minimal_symbol
));
1420 mcount
+= m_msym_bunch_index
;
1421 m_msym_bunch_index
= BUNCH_SIZE
;
1424 /* Sort the minimal symbols by address. */
1426 std::sort (msymbols
, msymbols
+ mcount
, minimal_symbol_is_less_than
);
1428 /* Compact out any duplicates, and free up whatever space we are
1431 mcount
= compact_minimal_symbols (msymbols
, mcount
, m_objfile
);
1432 msym_holder
.reset (XRESIZEVEC (struct minimal_symbol
,
1433 msym_holder
.release (),
1436 /* Attach the minimal symbol table to the specified objfile.
1437 The strings themselves are also located in the storage_obstack
1440 if (m_objfile
->per_bfd
->minimal_symbol_count
!= 0)
1441 clear_minimal_symbol_hash_tables (m_objfile
);
1443 m_objfile
->per_bfd
->minimal_symbol_count
= mcount
;
1444 m_objfile
->per_bfd
->msymbols
= std::move (msym_holder
);
1447 /* Mutex that is used when modifying or accessing the demangled
1449 std::mutex demangled_mutex
;
1452 std::vector
<computed_hash_values
> hash_values (mcount
);
1454 msymbols
= m_objfile
->per_bfd
->msymbols
.get ();
1455 /* Arbitrarily require at least 10 elements in a thread. */
1456 gdb::parallel_for_each (10, &msymbols
[0], &msymbols
[mcount
],
1457 [&] (minimal_symbol
*start
, minimal_symbol
*end
)
1459 for (minimal_symbol
*msym
= start
; msym
< end
; ++msym
)
1461 size_t idx
= msym
- msymbols
;
1462 hash_values
[idx
].name_length
= strlen (msym
->linkage_name ());
1463 if (!msym
->name_set
)
1465 /* This will be freed later, by compute_and_set_names. */
1466 gdb::unique_xmalloc_ptr
<char> demangled_name
1467 = symbol_find_demangled_name (msym
, msym
->linkage_name ());
1468 msym
->set_demangled_name
1469 (demangled_name
.release (),
1470 &m_objfile
->per_bfd
->storage_obstack
);
1473 /* This mangled_name_hash computation has to be outside of
1474 the name_set check, or compute_and_set_names below will
1475 be called with an invalid hash value. */
1476 hash_values
[idx
].mangled_name_hash
1477 = fast_hash (msym
->linkage_name (),
1478 hash_values
[idx
].name_length
);
1479 hash_values
[idx
].minsym_hash
1480 = msymbol_hash (msym
->linkage_name ());
1481 /* We only use this hash code if the search name differs
1482 from the linkage name. See the code in
1483 build_minimal_symbol_hash_tables. */
1484 if (msym
->search_name () != msym
->linkage_name ())
1485 hash_values
[idx
].minsym_demangled_hash
1486 = search_name_hash (msym
->language (), msym
->search_name ());
1489 /* To limit how long we hold the lock, we only acquire it here
1490 and not while we demangle the names above. */
1492 std::lock_guard
<std::mutex
> guard (demangled_mutex
);
1494 for (minimal_symbol
*msym
= start
; msym
< end
; ++msym
)
1496 size_t idx
= msym
- msymbols
;
1497 msym
->compute_and_set_names
1498 (gdb::string_view (msym
->linkage_name (),
1499 hash_values
[idx
].name_length
),
1502 hash_values
[idx
].mangled_name_hash
);
1507 build_minimal_symbol_hash_tables (m_objfile
, hash_values
);
1511 /* Check if PC is in a shared library trampoline code stub.
1512 Return minimal symbol for the trampoline entry or NULL if PC is not
1513 in a trampoline code stub. */
1515 static struct minimal_symbol
*
1516 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc
)
1518 bound_minimal_symbol msymbol
1519 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
1520 lookup_msym_prefer::TRAMPOLINE
);
1522 if (msymbol
.minsym
!= NULL
1523 && msymbol
.minsym
->type () == mst_solib_trampoline
)
1524 return msymbol
.minsym
;
1528 /* If PC is in a shared library trampoline code stub, return the
1529 address of the `real' function belonging to the stub.
1530 Return 0 if PC is not in a trampoline code stub or if the real
1531 function is not found in the minimal symbol table.
1533 We may fail to find the right function if a function with the
1534 same name is defined in more than one shared library, but this
1535 is considered bad programming style. We could return 0 if we find
1536 a duplicate function in case this matters someday. */
1539 find_solib_trampoline_target (frame_info_ptr frame
, CORE_ADDR pc
)
1541 struct minimal_symbol
*tsymbol
= lookup_solib_trampoline_symbol_by_pc (pc
);
1543 if (tsymbol
!= NULL
)
1545 for (objfile
*objfile
: current_program_space
->objfiles ())
1547 for (minimal_symbol
*msymbol
: objfile
->msymbols ())
1549 /* Also handle minimal symbols pointing to function
1551 if ((msymbol
->type () == mst_text
1552 || msymbol
->type () == mst_text_gnu_ifunc
1553 || msymbol
->type () == mst_data
1554 || msymbol
->type () == mst_data_gnu_ifunc
)
1555 && strcmp (msymbol
->linkage_name (),
1556 tsymbol
->linkage_name ()) == 0)
1560 /* Ignore data symbols that are not function
1562 if (msymbol_is_function (objfile
, msymbol
, &func
))
1571 /* See minsyms.h. */
1574 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym
)
1577 struct obj_section
*obj_section
;
1579 struct minimal_symbol
*iter
, *msymbol
;
1581 gdb_assert (minsym
.minsym
!= NULL
);
1583 /* If the minimal symbol has a size, use it. Otherwise use the
1584 lesser of the next minimal symbol in the same section, or the end
1585 of the section, as the end of the function. */
1587 if (minsym
.minsym
->size () != 0)
1588 return minsym
.value_address () + minsym
.minsym
->size ();
1590 /* Step over other symbols at this same address, and symbols in
1591 other sections, to find the next symbol in this section with a
1592 different address. */
1594 struct minimal_symbol
*past_the_end
1595 = (minsym
.objfile
->per_bfd
->msymbols
.get ()
1596 + minsym
.objfile
->per_bfd
->minimal_symbol_count
);
1597 msymbol
= minsym
.minsym
;
1598 section
= msymbol
->section_index ();
1599 for (iter
= msymbol
+ 1; iter
!= past_the_end
; ++iter
)
1601 if ((iter
->value_raw_address ()
1602 != msymbol
->value_raw_address ())
1603 && iter
->section_index () == section
)
1607 obj_section
= minsym
.obj_section ();
1608 if (iter
!= past_the_end
1609 && (iter
->value_address (minsym
.objfile
)
1610 < obj_section
->endaddr ()))
1611 result
= iter
->value_address (minsym
.objfile
);
1613 /* We got the start address from the last msymbol in the objfile.
1614 So the end address is the end of the section. */
1615 result
= obj_section
->endaddr ();