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 "gdbsupport/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 gdbsupport/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
))
523 lookup_minimal_symbol_linkage (const char *name
, struct objfile
*objf
)
525 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
527 for (objfile
*objfile
: objf
->separate_debug_objfiles ())
529 for (minimal_symbol
*msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
531 msymbol
= msymbol
->hash_next
)
533 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0
534 && (MSYMBOL_TYPE (msymbol
) == mst_data
535 || MSYMBOL_TYPE (msymbol
) == mst_bss
))
536 return {msymbol
, objfile
};
545 struct bound_minimal_symbol
546 lookup_minimal_symbol_text (const char *name
, struct objfile
*objf
)
548 struct minimal_symbol
*msymbol
;
549 struct bound_minimal_symbol found_symbol
= { NULL
, NULL
};
550 struct bound_minimal_symbol found_file_symbol
= { NULL
, NULL
};
552 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
554 for (objfile
*objfile
: current_program_space
->objfiles ())
556 if (found_symbol
.minsym
!= NULL
)
559 if (objf
== NULL
|| objf
== objfile
560 || objf
== objfile
->separate_debug_objfile_backlink
)
562 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
563 msymbol
!= NULL
&& found_symbol
.minsym
== NULL
;
564 msymbol
= msymbol
->hash_next
)
566 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0 &&
567 (MSYMBOL_TYPE (msymbol
) == mst_text
568 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
569 || MSYMBOL_TYPE (msymbol
) == mst_file_text
))
571 switch (MSYMBOL_TYPE (msymbol
))
574 found_file_symbol
.minsym
= msymbol
;
575 found_file_symbol
.objfile
= objfile
;
578 found_symbol
.minsym
= msymbol
;
579 found_symbol
.objfile
= objfile
;
586 /* External symbols are best. */
587 if (found_symbol
.minsym
)
590 /* File-local symbols are next best. */
591 return found_file_symbol
;
596 struct minimal_symbol
*
597 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc
, const char *name
,
598 struct objfile
*objf
)
600 struct minimal_symbol
*msymbol
;
602 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
604 for (objfile
*objfile
: current_program_space
->objfiles ())
606 if (objf
== NULL
|| objf
== objfile
607 || objf
== objfile
->separate_debug_objfile_backlink
)
609 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
611 msymbol
= msymbol
->hash_next
)
613 if (MSYMBOL_VALUE_ADDRESS (objfile
, msymbol
) == pc
614 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol
), name
) == 0)
623 /* A helper function that makes *PC section-relative. This searches
624 the sections of OBJFILE and if *PC is in a section, it subtracts
625 the section offset and returns true. Otherwise it returns
629 frob_address (struct objfile
*objfile
, CORE_ADDR
*pc
)
631 struct obj_section
*iter
;
633 ALL_OBJFILE_OSECTIONS (objfile
, iter
)
635 if (*pc
>= obj_section_addr (iter
) && *pc
< obj_section_endaddr (iter
))
637 *pc
-= obj_section_offset (iter
);
645 /* Helper for lookup_minimal_symbol_by_pc_section. Convert a
646 lookup_msym_prefer to a minimal_symbol_type. */
648 static minimal_symbol_type
649 msym_prefer_to_msym_type (lookup_msym_prefer prefer
)
653 case lookup_msym_prefer::TEXT
:
655 case lookup_msym_prefer::TRAMPOLINE
:
656 return mst_solib_trampoline
;
657 case lookup_msym_prefer::GNU_IFUNC
:
658 return mst_text_gnu_ifunc
;
661 /* Assert here instead of in a default switch case above so that
662 -Wswitch warns if a new enumerator is added. */
663 gdb_assert_not_reached ("unhandled lookup_msym_prefer");
666 /* Search through the minimal symbol table for each objfile and find
667 the symbol whose address is the largest address that is still less
668 than or equal to PC, and matches SECTION (which is not NULL).
669 Returns a pointer to the minimal symbol if such a symbol is found,
670 or NULL if PC is not in a suitable range.
671 Note that we need to look through ALL the minimal symbol tables
672 before deciding on the symbol that comes closest to the specified PC.
673 This is because objfiles can overlap, for example objfile A has .text
674 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
677 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
678 there are text and trampoline symbols at the same address.
679 Otherwise prefer mst_text symbols. */
682 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in
, struct obj_section
*section
,
683 lookup_msym_prefer prefer
)
688 struct minimal_symbol
*msymbol
;
689 struct minimal_symbol
*best_symbol
= NULL
;
690 struct objfile
*best_objfile
= NULL
;
691 struct bound_minimal_symbol result
;
695 section
= find_pc_section (pc_in
);
700 minimal_symbol_type want_type
= msym_prefer_to_msym_type (prefer
);
702 /* We can not require the symbol found to be in section, because
703 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
704 symbol - but find_pc_section won't return an absolute section and
705 hence the code below would skip over absolute symbols. We can
706 still take advantage of the call to find_pc_section, though - the
707 object file still must match. In case we have separate debug
708 files, search both the file and its separate debug file. There's
709 no telling which one will have the minimal symbols. */
711 gdb_assert (section
!= NULL
);
713 for (objfile
*objfile
: section
->objfile
->separate_debug_objfiles ())
715 CORE_ADDR pc
= pc_in
;
717 /* If this objfile has a minimal symbol table, go search it
718 using a binary search. */
720 if (objfile
->per_bfd
->minimal_symbol_count
> 0)
722 int best_zero_sized
= -1;
724 msymbol
= objfile
->per_bfd
->msymbols
.get ();
726 hi
= objfile
->per_bfd
->minimal_symbol_count
- 1;
728 /* This code assumes that the minimal symbols are sorted by
729 ascending address values. If the pc value is greater than or
730 equal to the first symbol's address, then some symbol in this
731 minimal symbol table is a suitable candidate for being the
732 "best" symbol. This includes the last real symbol, for cases
733 where the pc value is larger than any address in this vector.
735 By iterating until the address associated with the current
736 hi index (the endpoint of the test interval) is less than
737 or equal to the desired pc value, we accomplish two things:
738 (1) the case where the pc value is larger than any minimal
739 symbol address is trivially solved, (2) the address associated
740 with the hi index is always the one we want when the interation
741 terminates. In essence, we are iterating the test interval
742 down until the pc value is pushed out of it from the high end.
744 Warning: this code is trickier than it would appear at first. */
746 if (frob_address (objfile
, &pc
)
747 && pc
>= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[lo
]))
749 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]) > pc
)
751 /* pc is still strictly less than highest address. */
752 /* Note "new" will always be >= lo. */
753 newobj
= (lo
+ hi
) / 2;
754 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[newobj
]) >= pc
)
765 /* If we have multiple symbols at the same address, we want
766 hi to point to the last one. That way we can find the
767 right symbol if it has an index greater than hi. */
768 while (hi
< objfile
->per_bfd
->minimal_symbol_count
- 1
769 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
770 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
+ 1])))
773 /* Skip various undesirable symbols. */
776 /* Skip any absolute symbols. This is apparently
777 what adb and dbx do, and is needed for the CM-5.
778 There are two known possible problems: (1) on
779 ELF, apparently end, edata, etc. are absolute.
780 Not sure ignoring them here is a big deal, but if
781 we want to use them, the fix would go in
782 elfread.c. (2) I think shared library entry
783 points on the NeXT are absolute. If we want
784 special handling for this it probably should be
785 triggered by a special mst_abs_or_lib or some
788 if (MSYMBOL_TYPE (&msymbol
[hi
]) == mst_abs
)
794 /* If SECTION was specified, skip any symbol from
797 /* Some types of debug info, such as COFF,
798 don't fill the bfd_section member, so don't
799 throw away symbols on those platforms. */
800 && MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]) != NULL
801 && (!matching_obj_sections
802 (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]),
809 /* If we are looking for a trampoline and this is a
810 text symbol, or the other way around, check the
811 preceding symbol too. If they are otherwise
812 identical prefer that one. */
814 && MSYMBOL_TYPE (&msymbol
[hi
]) != want_type
815 && MSYMBOL_TYPE (&msymbol
[hi
- 1]) == want_type
816 && (MSYMBOL_SIZE (&msymbol
[hi
])
817 == MSYMBOL_SIZE (&msymbol
[hi
- 1]))
818 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
819 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1]))
820 && (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
])
821 == MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
- 1])))
827 /* If the minimal symbol has a zero size, save it
828 but keep scanning backwards looking for one with
829 a non-zero size. A zero size may mean that the
830 symbol isn't an object or function (e.g. a
831 label), or it may just mean that the size was not
833 if (MSYMBOL_SIZE (&msymbol
[hi
]) == 0)
835 if (best_zero_sized
== -1)
836 best_zero_sized
= hi
;
841 /* If we are past the end of the current symbol, try
842 the previous symbol if it has a larger overlapping
843 size. This happens on i686-pc-linux-gnu with glibc;
844 the nocancel variants of system calls are inside
845 the cancellable variants, but both have sizes. */
847 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
848 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
849 + MSYMBOL_SIZE (&msymbol
[hi
]))
850 && pc
< (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1])
851 + MSYMBOL_SIZE (&msymbol
[hi
- 1])))
857 /* Otherwise, this symbol must be as good as we're going
862 /* If HI has a zero size, and best_zero_sized is set,
863 then we had two or more zero-sized symbols; prefer
864 the first one we found (which may have a higher
865 address). Also, if we ran off the end, be sure
867 if (best_zero_sized
!= -1
868 && (hi
< 0 || MSYMBOL_SIZE (&msymbol
[hi
]) == 0))
869 hi
= best_zero_sized
;
871 /* If the minimal symbol has a non-zero size, and this
872 PC appears to be outside the symbol's contents, then
873 refuse to use this symbol. If we found a zero-sized
874 symbol with an address greater than this symbol's,
875 use that instead. We assume that if symbols have
876 specified sizes, they do not overlap. */
879 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
880 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
881 + MSYMBOL_SIZE (&msymbol
[hi
])))
883 if (best_zero_sized
!= -1)
884 hi
= best_zero_sized
;
886 /* Go on to the next object file. */
890 /* The minimal symbol indexed by hi now is the best one in this
891 objfile's minimal symbol table. See if it is the best one
895 && ((best_symbol
== NULL
) ||
896 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol
) <
897 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]))))
899 best_symbol
= &msymbol
[hi
];
900 best_objfile
= objfile
;
906 result
.minsym
= best_symbol
;
907 result
.objfile
= best_objfile
;
913 struct bound_minimal_symbol
914 lookup_minimal_symbol_by_pc (CORE_ADDR pc
)
916 return lookup_minimal_symbol_by_pc_section (pc
, NULL
);
919 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
922 in_gnu_ifunc_stub (CORE_ADDR pc
)
924 bound_minimal_symbol msymbol
925 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
926 lookup_msym_prefer::GNU_IFUNC
);
927 return msymbol
.minsym
&& MSYMBOL_TYPE (msymbol
.minsym
) == mst_text_gnu_ifunc
;
930 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
933 stub_gnu_ifunc_resolve_addr (struct gdbarch
*gdbarch
, CORE_ADDR pc
)
935 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
936 "the ELF support compiled in."),
937 paddress (gdbarch
, pc
));
940 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
943 stub_gnu_ifunc_resolve_name (const char *function_name
,
944 CORE_ADDR
*function_address_p
)
946 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
947 "the ELF support compiled in."),
951 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
954 stub_gnu_ifunc_resolver_stop (struct breakpoint
*b
)
956 internal_error (__FILE__
, __LINE__
,
957 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
960 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
963 stub_gnu_ifunc_resolver_return_stop (struct breakpoint
*b
)
965 internal_error (__FILE__
, __LINE__
,
966 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
969 /* See elf_gnu_ifunc_fns for its real implementation. */
971 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns
=
973 stub_gnu_ifunc_resolve_addr
,
974 stub_gnu_ifunc_resolve_name
,
975 stub_gnu_ifunc_resolver_stop
,
976 stub_gnu_ifunc_resolver_return_stop
,
979 /* A placeholder for &elf_gnu_ifunc_fns. */
981 const struct gnu_ifunc_fns
*gnu_ifunc_fns_p
= &stub_gnu_ifunc_fns
;
985 /* Return leading symbol character for a BFD. If BFD is NULL,
986 return the leading symbol character from the main objfile. */
989 get_symbol_leading_char (bfd
*abfd
)
992 return bfd_get_symbol_leading_char (abfd
);
993 if (symfile_objfile
!= NULL
&& symfile_objfile
->obfd
!= NULL
)
994 return bfd_get_symbol_leading_char (symfile_objfile
->obfd
);
1000 minimal_symbol_reader::minimal_symbol_reader (struct objfile
*obj
)
1002 m_msym_bunch (NULL
),
1003 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1004 first call to save a minimal symbol to allocate the memory for
1006 m_msym_bunch_index (BUNCH_SIZE
),
1011 /* Discard the currently collected minimal symbols, if any. If we wish
1012 to save them for later use, we must have already copied them somewhere
1013 else before calling this function. */
1015 minimal_symbol_reader::~minimal_symbol_reader ()
1017 struct msym_bunch
*next
;
1019 while (m_msym_bunch
!= NULL
)
1021 next
= m_msym_bunch
->next
;
1022 xfree (m_msym_bunch
);
1023 m_msym_bunch
= next
;
1027 /* See minsyms.h. */
1030 minimal_symbol_reader::record (const char *name
, CORE_ADDR address
,
1031 enum minimal_symbol_type ms_type
)
1038 case mst_text_gnu_ifunc
:
1040 case mst_solib_trampoline
:
1041 section
= SECT_OFF_TEXT (m_objfile
);
1044 case mst_data_gnu_ifunc
:
1046 section
= SECT_OFF_DATA (m_objfile
);
1050 section
= SECT_OFF_BSS (m_objfile
);
1056 record_with_info (name
, address
, ms_type
, section
);
1059 /* Convert an enumerator of type minimal_symbol_type to its string
1063 mst_str (minimal_symbol_type t
)
1065 #define MST_TO_STR(x) case x: return #x;
1068 MST_TO_STR (mst_unknown
);
1069 MST_TO_STR (mst_text
);
1070 MST_TO_STR (mst_text_gnu_ifunc
);
1071 MST_TO_STR (mst_slot_got_plt
);
1072 MST_TO_STR (mst_data
);
1073 MST_TO_STR (mst_bss
);
1074 MST_TO_STR (mst_abs
);
1075 MST_TO_STR (mst_solib_trampoline
);
1076 MST_TO_STR (mst_file_text
);
1077 MST_TO_STR (mst_file_data
);
1078 MST_TO_STR (mst_file_bss
);
1086 /* See minsyms.h. */
1088 struct minimal_symbol
*
1089 minimal_symbol_reader::record_full (const char *name
, int name_len
,
1090 bool copy_name
, CORE_ADDR address
,
1091 enum minimal_symbol_type ms_type
,
1094 struct msym_bunch
*newobj
;
1095 struct minimal_symbol
*msymbol
;
1097 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1098 the minimal symbols, because if there is also another symbol
1099 at the same address (e.g. the first function of the file),
1100 lookup_minimal_symbol_by_pc would have no way of getting the
1102 if (ms_type
== mst_file_text
&& name
[0] == 'g'
1103 && (strcmp (name
, GCC_COMPILED_FLAG_SYMBOL
) == 0
1104 || strcmp (name
, GCC2_COMPILED_FLAG_SYMBOL
) == 0))
1107 /* It's safe to strip the leading char here once, since the name
1108 is also stored stripped in the minimal symbol table. */
1109 if (name
[0] == get_symbol_leading_char (m_objfile
->obfd
))
1115 if (ms_type
== mst_file_text
&& startswith (name
, "__gnu_compiled"))
1118 if (symtab_create_debug
>= 2)
1119 printf_unfiltered ("Recording minsym: %-21s %18s %4d %s\n",
1120 mst_str (ms_type
), hex_string (address
), section
, name
);
1122 if (m_msym_bunch_index
== BUNCH_SIZE
)
1124 newobj
= XCNEW (struct msym_bunch
);
1125 m_msym_bunch_index
= 0;
1126 newobj
->next
= m_msym_bunch
;
1127 m_msym_bunch
= newobj
;
1129 msymbol
= &m_msym_bunch
->contents
[m_msym_bunch_index
];
1130 symbol_set_language (msymbol
, language_auto
,
1131 &m_objfile
->per_bfd
->storage_obstack
);
1132 symbol_set_names (msymbol
, name
, name_len
, copy_name
, m_objfile
->per_bfd
);
1134 SET_MSYMBOL_VALUE_ADDRESS (msymbol
, address
);
1135 MSYMBOL_SECTION (msymbol
) = section
;
1137 MSYMBOL_TYPE (msymbol
) = ms_type
;
1139 /* If we already read minimal symbols for this objfile, then don't
1140 ever allocate a new one. */
1141 if (!m_objfile
->per_bfd
->minsyms_read
)
1143 m_msym_bunch_index
++;
1144 m_objfile
->per_bfd
->n_minsyms
++;
1150 /* Compare two minimal symbols by address and return true if FN1's address
1151 is less than FN2's, so that we sort into unsigned numeric order.
1152 Within groups with the same address, sort by name. */
1155 minimal_symbol_is_less_than (const minimal_symbol
&fn1
,
1156 const minimal_symbol
&fn2
)
1158 if (MSYMBOL_VALUE_RAW_ADDRESS (&fn1
) < MSYMBOL_VALUE_RAW_ADDRESS (&fn2
))
1160 return true; /* addr 1 is less than addr 2. */
1162 else if (MSYMBOL_VALUE_RAW_ADDRESS (&fn1
) > MSYMBOL_VALUE_RAW_ADDRESS (&fn2
))
1164 return false; /* addr 1 is greater than addr 2. */
1167 /* addrs are equal: sort by name */
1169 const char *name1
= MSYMBOL_LINKAGE_NAME (&fn1
);
1170 const char *name2
= MSYMBOL_LINKAGE_NAME (&fn2
);
1172 if (name1
&& name2
) /* both have names */
1173 return strcmp (name1
, name2
) < 0;
1175 return true; /* fn1 has no name, so it is "less". */
1176 else if (name1
) /* fn2 has no name, so it is "less". */
1179 return false; /* Neither has a name, so they're equal. */
1183 /* Compact duplicate entries out of a minimal symbol table by walking
1184 through the table and compacting out entries with duplicate addresses
1185 and matching names. Return the number of entries remaining.
1187 On entry, the table resides between msymbol[0] and msymbol[mcount].
1188 On exit, it resides between msymbol[0] and msymbol[result_count].
1190 When files contain multiple sources of symbol information, it is
1191 possible for the minimal symbol table to contain many duplicate entries.
1192 As an example, SVR4 systems use ELF formatted object files, which
1193 usually contain at least two different types of symbol tables (a
1194 standard ELF one and a smaller dynamic linking table), as well as
1195 DWARF debugging information for files compiled with -g.
1197 Without compacting, the minimal symbol table for gdb itself contains
1198 over a 1000 duplicates, about a third of the total table size. Aside
1199 from the potential trap of not noticing that two successive entries
1200 identify the same location, this duplication impacts the time required
1201 to linearly scan the table, which is done in a number of places. So we
1202 just do one linear scan here and toss out the duplicates.
1204 Since the different sources of information for each symbol may
1205 have different levels of "completeness", we may have duplicates
1206 that have one entry with type "mst_unknown" and the other with a
1207 known type. So if the one we are leaving alone has type mst_unknown,
1208 overwrite its type with the type from the one we are compacting out. */
1211 compact_minimal_symbols (struct minimal_symbol
*msymbol
, int mcount
,
1212 struct objfile
*objfile
)
1214 struct minimal_symbol
*copyfrom
;
1215 struct minimal_symbol
*copyto
;
1219 copyfrom
= copyto
= msymbol
;
1220 while (copyfrom
< msymbol
+ mcount
- 1)
1222 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom
)
1223 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom
+ 1))
1224 && MSYMBOL_SECTION (copyfrom
) == MSYMBOL_SECTION (copyfrom
+ 1)
1225 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom
),
1226 MSYMBOL_LINKAGE_NAME ((copyfrom
+ 1))) == 0)
1228 if (MSYMBOL_TYPE ((copyfrom
+ 1)) == mst_unknown
)
1230 MSYMBOL_TYPE ((copyfrom
+ 1)) = MSYMBOL_TYPE (copyfrom
);
1235 *copyto
++ = *copyfrom
++;
1237 *copyto
++ = *copyfrom
++;
1238 mcount
= copyto
- msymbol
;
1243 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1244 after compacting or sorting the table since the entries move around
1245 thus causing the internal minimal_symbol pointers to become jumbled. */
1248 build_minimal_symbol_hash_tables (struct objfile
*objfile
)
1251 struct minimal_symbol
*msym
;
1253 /* Clear the hash tables. */
1254 for (i
= 0; i
< MINIMAL_SYMBOL_HASH_SIZE
; i
++)
1256 objfile
->per_bfd
->msymbol_hash
[i
] = 0;
1257 objfile
->per_bfd
->msymbol_demangled_hash
[i
] = 0;
1260 /* Now, (re)insert the actual entries. */
1261 for ((i
= objfile
->per_bfd
->minimal_symbol_count
,
1262 msym
= objfile
->per_bfd
->msymbols
.get ());
1266 msym
->hash_next
= 0;
1267 add_minsym_to_hash_table (msym
, objfile
->per_bfd
->msymbol_hash
);
1269 msym
->demangled_hash_next
= 0;
1270 if (MSYMBOL_SEARCH_NAME (msym
) != MSYMBOL_LINKAGE_NAME (msym
))
1271 add_minsym_to_demangled_hash_table (msym
, objfile
);
1275 /* Add the minimal symbols in the existing bunches to the objfile's official
1276 minimal symbol table. In most cases there is no minimal symbol table yet
1277 for this objfile, and the existing bunches are used to create one. Once
1278 in a while (for shared libraries for example), we add symbols (e.g. common
1279 symbols) to an existing objfile. */
1282 minimal_symbol_reader::install ()
1285 struct msym_bunch
*bunch
;
1286 struct minimal_symbol
*msymbols
;
1289 if (m_objfile
->per_bfd
->minsyms_read
)
1292 if (m_msym_count
> 0)
1294 if (symtab_create_debug
)
1296 fprintf_unfiltered (gdb_stdlog
,
1297 "Installing %d minimal symbols of objfile %s.\n",
1298 m_msym_count
, objfile_name (m_objfile
));
1301 /* Allocate enough space, into which we will gather the bunches
1302 of new and existing minimal symbols, sort them, and then
1303 compact out the duplicate entries. Once we have a final
1304 table, we will give back the excess space. */
1306 alloc_count
= m_msym_count
+ m_objfile
->per_bfd
->minimal_symbol_count
;
1307 gdb::unique_xmalloc_ptr
<minimal_symbol
>
1308 msym_holder (XNEWVEC (minimal_symbol
, alloc_count
));
1309 msymbols
= msym_holder
.get ();
1311 /* Copy in the existing minimal symbols, if there are any. */
1313 if (m_objfile
->per_bfd
->minimal_symbol_count
)
1314 memcpy (msymbols
, m_objfile
->per_bfd
->msymbols
.get (),
1315 m_objfile
->per_bfd
->minimal_symbol_count
1316 * sizeof (struct minimal_symbol
));
1318 /* Walk through the list of minimal symbol bunches, adding each symbol
1319 to the new contiguous array of symbols. Note that we start with the
1320 current, possibly partially filled bunch (thus we use the current
1321 msym_bunch_index for the first bunch we copy over), and thereafter
1322 each bunch is full. */
1324 mcount
= m_objfile
->per_bfd
->minimal_symbol_count
;
1326 for (bunch
= m_msym_bunch
; bunch
!= NULL
; bunch
= bunch
->next
)
1328 memcpy (&msymbols
[mcount
], &bunch
->contents
[0],
1329 m_msym_bunch_index
* sizeof (struct minimal_symbol
));
1330 mcount
+= m_msym_bunch_index
;
1331 m_msym_bunch_index
= BUNCH_SIZE
;
1334 /* Sort the minimal symbols by address. */
1336 std::sort (msymbols
, msymbols
+ mcount
, minimal_symbol_is_less_than
);
1338 /* Compact out any duplicates, and free up whatever space we are
1341 mcount
= compact_minimal_symbols (msymbols
, mcount
, m_objfile
);
1342 msym_holder
.reset (XRESIZEVEC (struct minimal_symbol
,
1343 msym_holder
.release (),
1346 /* Attach the minimal symbol table to the specified objfile.
1347 The strings themselves are also located in the storage_obstack
1350 m_objfile
->per_bfd
->minimal_symbol_count
= mcount
;
1351 m_objfile
->per_bfd
->msymbols
= std::move (msym_holder
);
1353 build_minimal_symbol_hash_tables (m_objfile
);
1357 /* Check if PC is in a shared library trampoline code stub.
1358 Return minimal symbol for the trampoline entry or NULL if PC is not
1359 in a trampoline code stub. */
1361 static struct minimal_symbol
*
1362 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc
)
1364 bound_minimal_symbol msymbol
1365 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
1366 lookup_msym_prefer::TRAMPOLINE
);
1368 if (msymbol
.minsym
!= NULL
1369 && MSYMBOL_TYPE (msymbol
.minsym
) == mst_solib_trampoline
)
1370 return msymbol
.minsym
;
1374 /* If PC is in a shared library trampoline code stub, return the
1375 address of the `real' function belonging to the stub.
1376 Return 0 if PC is not in a trampoline code stub or if the real
1377 function is not found in the minimal symbol table.
1379 We may fail to find the right function if a function with the
1380 same name is defined in more than one shared library, but this
1381 is considered bad programming style. We could return 0 if we find
1382 a duplicate function in case this matters someday. */
1385 find_solib_trampoline_target (struct frame_info
*frame
, CORE_ADDR pc
)
1387 struct minimal_symbol
*tsymbol
= lookup_solib_trampoline_symbol_by_pc (pc
);
1389 if (tsymbol
!= NULL
)
1391 for (objfile
*objfile
: current_program_space
->objfiles ())
1393 for (minimal_symbol
*msymbol
: objfile
->msymbols ())
1395 /* Also handle minimal symbols pointing to function
1397 if ((MSYMBOL_TYPE (msymbol
) == mst_text
1398 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
1399 || MSYMBOL_TYPE (msymbol
) == mst_data
1400 || MSYMBOL_TYPE (msymbol
) == mst_data_gnu_ifunc
)
1401 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol
),
1402 MSYMBOL_LINKAGE_NAME (tsymbol
)) == 0)
1406 /* Ignore data symbols that are not function
1408 if (msymbol_is_function (objfile
, msymbol
, &func
))
1417 /* See minsyms.h. */
1420 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym
)
1423 struct obj_section
*obj_section
;
1425 struct minimal_symbol
*iter
, *msymbol
;
1427 gdb_assert (minsym
.minsym
!= NULL
);
1429 /* If the minimal symbol has a size, use it. Otherwise use the
1430 lesser of the next minimal symbol in the same section, or the end
1431 of the section, as the end of the function. */
1433 if (MSYMBOL_SIZE (minsym
.minsym
) != 0)
1434 return BMSYMBOL_VALUE_ADDRESS (minsym
) + MSYMBOL_SIZE (minsym
.minsym
);
1436 /* Step over other symbols at this same address, and symbols in
1437 other sections, to find the next symbol in this section with a
1438 different address. */
1440 struct minimal_symbol
*past_the_end
1441 = (minsym
.objfile
->per_bfd
->msymbols
.get ()
1442 + minsym
.objfile
->per_bfd
->minimal_symbol_count
);
1443 msymbol
= minsym
.minsym
;
1444 section
= MSYMBOL_SECTION (msymbol
);
1445 for (iter
= msymbol
+ 1; iter
!= past_the_end
; ++iter
)
1447 if ((MSYMBOL_VALUE_RAW_ADDRESS (iter
)
1448 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol
))
1449 && MSYMBOL_SECTION (iter
) == section
)
1453 obj_section
= MSYMBOL_OBJ_SECTION (minsym
.objfile
, minsym
.minsym
);
1454 if (iter
!= past_the_end
1455 && (MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, iter
)
1456 < obj_section_endaddr (obj_section
)))
1457 result
= MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, iter
);
1459 /* We got the start address from the last msymbol in the objfile.
1460 So the end address is the end of the section. */
1461 result
= obj_section_endaddr (obj_section
);