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"
56 #include "gdbsupport/parallel-for.h"
65 msymbol_is_function (struct objfile
*objfile
, minimal_symbol
*minsym
,
66 CORE_ADDR
*func_address_p
)
68 CORE_ADDR msym_addr
= MSYMBOL_VALUE_ADDRESS (objfile
, minsym
);
72 case mst_slot_got_plt
:
78 case mst_data_gnu_ifunc
:
80 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
82 = gdbarch_convert_from_func_ptr_addr (gdbarch
, msym_addr
,
83 current_top_target ());
86 if (func_address_p
!= NULL
)
93 if (func_address_p
!= NULL
)
94 *func_address_p
= msym_addr
;
99 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
100 At the end, copy them all into one newly allocated array. */
102 #define BUNCH_SIZE 127
106 struct msym_bunch
*next
;
107 struct minimal_symbol contents
[BUNCH_SIZE
];
113 msymbol_hash_iw (const char *string
)
115 unsigned int hash
= 0;
117 while (*string
&& *string
!= '(')
119 string
= skip_spaces (string
);
120 if (*string
&& *string
!= '(')
122 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
132 msymbol_hash (const char *string
)
134 unsigned int hash
= 0;
136 for (; *string
; ++string
)
137 hash
= SYMBOL_HASH_NEXT (hash
, *string
);
141 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
143 add_minsym_to_hash_table (struct minimal_symbol
*sym
,
144 struct minimal_symbol
**table
)
146 if (sym
->hash_next
== NULL
)
149 = msymbol_hash (sym
->linkage_name ()) % MINIMAL_SYMBOL_HASH_SIZE
;
151 sym
->hash_next
= table
[hash
];
156 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
159 add_minsym_to_demangled_hash_table (struct minimal_symbol
*sym
,
160 struct objfile
*objfile
)
162 if (sym
->demangled_hash_next
== NULL
)
164 unsigned int hash
= search_name_hash (MSYMBOL_LANGUAGE (sym
),
165 sym
->search_name ());
167 objfile
->per_bfd
->demangled_hash_languages
.set (MSYMBOL_LANGUAGE (sym
));
169 struct minimal_symbol
**table
170 = objfile
->per_bfd
->msymbol_demangled_hash
;
171 unsigned int hash_index
= hash
% MINIMAL_SYMBOL_HASH_SIZE
;
172 sym
->demangled_hash_next
= table
[hash_index
];
173 table
[hash_index
] = sym
;
177 /* Worker object for lookup_minimal_symbol. Stores temporary results
178 while walking the symbol tables. */
180 struct found_minimal_symbols
182 /* External symbols are best. */
183 bound_minimal_symbol external_symbol
{};
185 /* File-local symbols are next best. */
186 bound_minimal_symbol file_symbol
{};
188 /* Symbols for shared library trampolines are next best. */
189 bound_minimal_symbol trampoline_symbol
{};
191 /* Called when a symbol name matches. Check if the minsym is a
192 better type than what we had already found, and record it in one
193 of the members fields if so. Returns true if we collected the
194 real symbol, in which case we can stop searching. */
195 bool maybe_collect (const char *sfile
, objfile
*objf
,
196 minimal_symbol
*msymbol
);
199 /* See declaration above. */
202 found_minimal_symbols::maybe_collect (const char *sfile
,
203 struct objfile
*objfile
,
204 minimal_symbol
*msymbol
)
206 switch (MSYMBOL_TYPE (msymbol
))
212 || filename_cmp (msymbol
->filename
, sfile
) == 0)
214 file_symbol
.minsym
= msymbol
;
215 file_symbol
.objfile
= objfile
;
219 case mst_solib_trampoline
:
221 /* If a trampoline symbol is found, we prefer to keep
222 looking for the *real* symbol. If the actual symbol
223 is not found, then we'll use the trampoline
225 if (trampoline_symbol
.minsym
== NULL
)
227 trampoline_symbol
.minsym
= msymbol
;
228 trampoline_symbol
.objfile
= objfile
;
234 external_symbol
.minsym
= msymbol
;
235 external_symbol
.objfile
= objfile
;
236 /* We have the real symbol. No use looking further. */
244 /* Walk the mangled name hash table, and pass each symbol whose name
245 matches LOOKUP_NAME according to NAMECMP to FOUND. */
248 lookup_minimal_symbol_mangled (const char *lookup_name
,
250 struct objfile
*objfile
,
251 struct minimal_symbol
**table
,
253 int (*namecmp
) (const char *, const char *),
254 found_minimal_symbols
&found
)
256 for (minimal_symbol
*msymbol
= table
[hash
];
258 msymbol
= msymbol
->hash_next
)
260 const char *symbol_name
= msymbol
->linkage_name ();
262 if (namecmp (symbol_name
, lookup_name
) == 0
263 && found
.maybe_collect (sfile
, objfile
, msymbol
))
268 /* Walk the demangled name hash table, and pass each symbol whose name
269 matches LOOKUP_NAME according to MATCHER to FOUND. */
272 lookup_minimal_symbol_demangled (const lookup_name_info
&lookup_name
,
274 struct objfile
*objfile
,
275 struct minimal_symbol
**table
,
277 symbol_name_matcher_ftype
*matcher
,
278 found_minimal_symbols
&found
)
280 for (minimal_symbol
*msymbol
= table
[hash
];
282 msymbol
= msymbol
->demangled_hash_next
)
284 const char *symbol_name
= msymbol
->search_name ();
286 if (matcher (symbol_name
, lookup_name
, NULL
)
287 && found
.maybe_collect (sfile
, objfile
, msymbol
))
292 /* Look through all the current minimal symbol tables and find the
293 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
294 the search to that objfile. If SFILE is non-NULL, the only file-scope
295 symbols considered will be from that source file (global symbols are
296 still preferred). Returns a pointer to the minimal symbol that
297 matches, or NULL if no match is found.
299 Note: One instance where there may be duplicate minimal symbols with
300 the same name is when the symbol tables for a shared library and the
301 symbol tables for an executable contain global symbols with the same
302 names (the dynamic linker deals with the duplication).
304 It's also possible to have minimal symbols with different mangled
305 names, but identical demangled names. For example, the GNU C++ v3
306 ABI requires the generation of two (or perhaps three) copies of
307 constructor functions --- "in-charge", "not-in-charge", and
308 "allocate" copies; destructors may be duplicated as well.
309 Obviously, there must be distinct mangled names for each of these,
310 but the demangled names are all the same: S::S or S::~S. */
312 struct bound_minimal_symbol
313 lookup_minimal_symbol (const char *name
, const char *sfile
,
314 struct objfile
*objf
)
316 found_minimal_symbols found
;
318 unsigned int mangled_hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
321 = (case_sensitivity
== case_sensitive_on
326 sfile
= lbasename (sfile
);
328 lookup_name_info
lookup_name (name
, symbol_name_match_type::FULL
);
330 for (objfile
*objfile
: current_program_space
->objfiles ())
332 if (found
.external_symbol
.minsym
!= NULL
)
335 if (objf
== NULL
|| objf
== objfile
336 || objf
== objfile
->separate_debug_objfile_backlink
)
338 if (symbol_lookup_debug
)
340 fprintf_unfiltered (gdb_stdlog
,
341 "lookup_minimal_symbol (%s, %s, %s)\n",
342 name
, sfile
!= NULL
? sfile
: "NULL",
343 objfile_debug_name (objfile
));
346 /* Do two passes: the first over the ordinary hash table,
347 and the second over the demangled hash table. */
348 lookup_minimal_symbol_mangled (name
, sfile
, objfile
,
349 objfile
->per_bfd
->msymbol_hash
,
350 mangled_hash
, mangled_cmp
, found
);
352 /* If not found, try the demangled hash table. */
353 if (found
.external_symbol
.minsym
== NULL
)
355 /* Once for each language in the demangled hash names
356 table (usually just zero or one languages). */
357 for (unsigned iter
= 0; iter
< nr_languages
; ++iter
)
359 if (!objfile
->per_bfd
->demangled_hash_languages
.test (iter
))
361 enum language lang
= (enum language
) iter
;
364 = (lookup_name
.search_name_hash (lang
)
365 % MINIMAL_SYMBOL_HASH_SIZE
);
367 symbol_name_matcher_ftype
*match
368 = get_symbol_name_matcher (language_def (lang
),
370 struct minimal_symbol
**msymbol_demangled_hash
371 = objfile
->per_bfd
->msymbol_demangled_hash
;
373 lookup_minimal_symbol_demangled (lookup_name
, sfile
, objfile
,
374 msymbol_demangled_hash
,
377 if (found
.external_symbol
.minsym
!= NULL
)
384 /* External symbols are best. */
385 if (found
.external_symbol
.minsym
!= NULL
)
387 if (symbol_lookup_debug
)
389 minimal_symbol
*minsym
= found
.external_symbol
.minsym
;
391 fprintf_unfiltered (gdb_stdlog
,
392 "lookup_minimal_symbol (...) = %s (external)\n",
393 host_address_to_string (minsym
));
395 return found
.external_symbol
;
398 /* File-local symbols are next best. */
399 if (found
.file_symbol
.minsym
!= NULL
)
401 if (symbol_lookup_debug
)
403 minimal_symbol
*minsym
= found
.file_symbol
.minsym
;
405 fprintf_unfiltered (gdb_stdlog
,
406 "lookup_minimal_symbol (...) = %s (file-local)\n",
407 host_address_to_string (minsym
));
409 return found
.file_symbol
;
412 /* Symbols for shared library trampolines are next best. */
413 if (found
.trampoline_symbol
.minsym
!= NULL
)
415 if (symbol_lookup_debug
)
417 minimal_symbol
*minsym
= found
.trampoline_symbol
.minsym
;
419 fprintf_unfiltered (gdb_stdlog
,
420 "lookup_minimal_symbol (...) = %s (trampoline)\n",
421 host_address_to_string (minsym
));
424 return found
.trampoline_symbol
;
428 if (symbol_lookup_debug
)
429 fprintf_unfiltered (gdb_stdlog
, "lookup_minimal_symbol (...) = NULL\n");
435 struct bound_minimal_symbol
436 lookup_bound_minimal_symbol (const char *name
)
438 return lookup_minimal_symbol (name
, NULL
, NULL
);
441 /* See gdbsupport/symbol.h. */
444 find_minimal_symbol_address (const char *name
, CORE_ADDR
*addr
,
445 struct objfile
*objfile
)
447 struct bound_minimal_symbol sym
448 = lookup_minimal_symbol (name
, NULL
, objfile
);
450 if (sym
.minsym
!= NULL
)
451 *addr
= BMSYMBOL_VALUE_ADDRESS (sym
);
453 return sym
.minsym
== NULL
;
456 /* Get the lookup name form best suitable for linkage name
460 linkage_name_str (const lookup_name_info
&lookup_name
)
462 /* Unlike most languages (including C++), Ada uses the
463 encoded/linkage name as the search name recorded in symbols. So
464 if debugging in Ada mode, prefer the Ada-encoded name. This also
465 makes Ada's verbatim match syntax ("<...>") work, because
466 "lookup_name.name()" includes the "<>"s, while
467 "lookup_name.ada().lookup_name()" is the encoded name with "<>"s
469 if (current_language
->la_language
== language_ada
)
470 return lookup_name
.ada ().lookup_name ().c_str ();
472 return lookup_name
.name ().c_str ();
478 iterate_over_minimal_symbols
479 (struct objfile
*objf
, const lookup_name_info
&lookup_name
,
480 gdb::function_view
<bool (struct minimal_symbol
*)> callback
)
482 /* The first pass is over the ordinary hash table. */
484 const char *name
= linkage_name_str (lookup_name
);
485 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
487 = (case_sensitivity
== case_sensitive_on
491 for (minimal_symbol
*iter
= objf
->per_bfd
->msymbol_hash
[hash
];
493 iter
= iter
->hash_next
)
495 if (mangled_cmp (iter
->linkage_name (), name
) == 0)
501 /* The second pass is over the demangled table. Once for each
502 language in the demangled hash names table (usually just zero or
504 for (unsigned liter
= 0; liter
< nr_languages
; ++liter
)
506 if (!objf
->per_bfd
->demangled_hash_languages
.test (liter
))
509 enum language lang
= (enum language
) liter
;
510 const language_defn
*lang_def
= language_def (lang
);
511 symbol_name_matcher_ftype
*name_match
512 = get_symbol_name_matcher (lang_def
, lookup_name
);
515 = lookup_name
.search_name_hash (lang
) % MINIMAL_SYMBOL_HASH_SIZE
;
516 for (minimal_symbol
*iter
= objf
->per_bfd
->msymbol_demangled_hash
[hash
];
518 iter
= iter
->demangled_hash_next
)
519 if (name_match (iter
->search_name (), lookup_name
, NULL
))
528 lookup_minimal_symbol_linkage (const char *name
, struct objfile
*objf
)
530 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
532 for (objfile
*objfile
: objf
->separate_debug_objfiles ())
534 for (minimal_symbol
*msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
536 msymbol
= msymbol
->hash_next
)
538 if (strcmp (msymbol
->linkage_name (), name
) == 0
539 && (MSYMBOL_TYPE (msymbol
) == mst_data
540 || MSYMBOL_TYPE (msymbol
) == mst_bss
))
541 return {msymbol
, objfile
};
550 struct bound_minimal_symbol
551 lookup_minimal_symbol_text (const char *name
, struct objfile
*objf
)
553 struct minimal_symbol
*msymbol
;
554 struct bound_minimal_symbol found_symbol
= { NULL
, NULL
};
555 struct bound_minimal_symbol found_file_symbol
= { NULL
, NULL
};
557 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
559 for (objfile
*objfile
: current_program_space
->objfiles ())
561 if (found_symbol
.minsym
!= NULL
)
564 if (objf
== NULL
|| objf
== objfile
565 || objf
== objfile
->separate_debug_objfile_backlink
)
567 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
568 msymbol
!= NULL
&& found_symbol
.minsym
== NULL
;
569 msymbol
= msymbol
->hash_next
)
571 if (strcmp (msymbol
->linkage_name (), name
) == 0 &&
572 (MSYMBOL_TYPE (msymbol
) == mst_text
573 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
574 || MSYMBOL_TYPE (msymbol
) == mst_file_text
))
576 switch (MSYMBOL_TYPE (msymbol
))
579 found_file_symbol
.minsym
= msymbol
;
580 found_file_symbol
.objfile
= objfile
;
583 found_symbol
.minsym
= msymbol
;
584 found_symbol
.objfile
= objfile
;
591 /* External symbols are best. */
592 if (found_symbol
.minsym
)
595 /* File-local symbols are next best. */
596 return found_file_symbol
;
601 struct minimal_symbol
*
602 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc
, const char *name
,
603 struct objfile
*objf
)
605 struct minimal_symbol
*msymbol
;
607 unsigned int hash
= msymbol_hash (name
) % MINIMAL_SYMBOL_HASH_SIZE
;
609 for (objfile
*objfile
: current_program_space
->objfiles ())
611 if (objf
== NULL
|| objf
== objfile
612 || objf
== objfile
->separate_debug_objfile_backlink
)
614 for (msymbol
= objfile
->per_bfd
->msymbol_hash
[hash
];
616 msymbol
= msymbol
->hash_next
)
618 if (MSYMBOL_VALUE_ADDRESS (objfile
, msymbol
) == pc
619 && strcmp (msymbol
->linkage_name (), name
) == 0)
628 /* A helper function that makes *PC section-relative. This searches
629 the sections of OBJFILE and if *PC is in a section, it subtracts
630 the section offset and returns true. Otherwise it returns
634 frob_address (struct objfile
*objfile
, CORE_ADDR
*pc
)
636 struct obj_section
*iter
;
638 ALL_OBJFILE_OSECTIONS (objfile
, iter
)
640 if (*pc
>= obj_section_addr (iter
) && *pc
< obj_section_endaddr (iter
))
642 *pc
-= obj_section_offset (iter
);
650 /* Helper for lookup_minimal_symbol_by_pc_section. Convert a
651 lookup_msym_prefer to a minimal_symbol_type. */
653 static minimal_symbol_type
654 msym_prefer_to_msym_type (lookup_msym_prefer prefer
)
658 case lookup_msym_prefer::TEXT
:
660 case lookup_msym_prefer::TRAMPOLINE
:
661 return mst_solib_trampoline
;
662 case lookup_msym_prefer::GNU_IFUNC
:
663 return mst_text_gnu_ifunc
;
666 /* Assert here instead of in a default switch case above so that
667 -Wswitch warns if a new enumerator is added. */
668 gdb_assert_not_reached ("unhandled lookup_msym_prefer");
671 /* Search through the minimal symbol table for each objfile and find
672 the symbol whose address is the largest address that is still less
673 than or equal to PC, and matches SECTION (which is not NULL).
674 Returns a pointer to the minimal symbol if such a symbol is found,
675 or NULL if PC is not in a suitable range.
676 Note that we need to look through ALL the minimal symbol tables
677 before deciding on the symbol that comes closest to the specified PC.
678 This is because objfiles can overlap, for example objfile A has .text
679 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
682 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
683 there are text and trampoline symbols at the same address.
684 Otherwise prefer mst_text symbols. */
687 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in
, struct obj_section
*section
,
688 lookup_msym_prefer prefer
)
693 struct minimal_symbol
*msymbol
;
694 struct minimal_symbol
*best_symbol
= NULL
;
695 struct objfile
*best_objfile
= NULL
;
696 struct bound_minimal_symbol result
;
700 section
= find_pc_section (pc_in
);
705 minimal_symbol_type want_type
= msym_prefer_to_msym_type (prefer
);
707 /* We can not require the symbol found to be in section, because
708 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
709 symbol - but find_pc_section won't return an absolute section and
710 hence the code below would skip over absolute symbols. We can
711 still take advantage of the call to find_pc_section, though - the
712 object file still must match. In case we have separate debug
713 files, search both the file and its separate debug file. There's
714 no telling which one will have the minimal symbols. */
716 gdb_assert (section
!= NULL
);
718 for (objfile
*objfile
: section
->objfile
->separate_debug_objfiles ())
720 CORE_ADDR pc
= pc_in
;
722 /* If this objfile has a minimal symbol table, go search it
723 using a binary search. */
725 if (objfile
->per_bfd
->minimal_symbol_count
> 0)
727 int best_zero_sized
= -1;
729 msymbol
= objfile
->per_bfd
->msymbols
.get ();
731 hi
= objfile
->per_bfd
->minimal_symbol_count
- 1;
733 /* This code assumes that the minimal symbols are sorted by
734 ascending address values. If the pc value is greater than or
735 equal to the first symbol's address, then some symbol in this
736 minimal symbol table is a suitable candidate for being the
737 "best" symbol. This includes the last real symbol, for cases
738 where the pc value is larger than any address in this vector.
740 By iterating until the address associated with the current
741 hi index (the endpoint of the test interval) is less than
742 or equal to the desired pc value, we accomplish two things:
743 (1) the case where the pc value is larger than any minimal
744 symbol address is trivially solved, (2) the address associated
745 with the hi index is always the one we want when the iteration
746 terminates. In essence, we are iterating the test interval
747 down until the pc value is pushed out of it from the high end.
749 Warning: this code is trickier than it would appear at first. */
751 if (frob_address (objfile
, &pc
)
752 && pc
>= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[lo
]))
754 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]) > pc
)
756 /* pc is still strictly less than highest address. */
757 /* Note "new" will always be >= lo. */
758 newobj
= (lo
+ hi
) / 2;
759 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[newobj
]) >= pc
)
770 /* If we have multiple symbols at the same address, we want
771 hi to point to the last one. That way we can find the
772 right symbol if it has an index greater than hi. */
773 while (hi
< objfile
->per_bfd
->minimal_symbol_count
- 1
774 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
775 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
+ 1])))
778 /* Skip various undesirable symbols. */
781 /* Skip any absolute symbols. This is apparently
782 what adb and dbx do, and is needed for the CM-5.
783 There are two known possible problems: (1) on
784 ELF, apparently end, edata, etc. are absolute.
785 Not sure ignoring them here is a big deal, but if
786 we want to use them, the fix would go in
787 elfread.c. (2) I think shared library entry
788 points on the NeXT are absolute. If we want
789 special handling for this it probably should be
790 triggered by a special mst_abs_or_lib or some
793 if (MSYMBOL_TYPE (&msymbol
[hi
]) == mst_abs
)
799 /* If SECTION was specified, skip any symbol from
802 /* Some types of debug info, such as COFF,
803 don't fill the bfd_section member, so don't
804 throw away symbols on those platforms. */
805 && MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]) != NULL
806 && (!matching_obj_sections
807 (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
]),
814 /* If we are looking for a trampoline and this is a
815 text symbol, or the other way around, check the
816 preceding symbol too. If they are otherwise
817 identical prefer that one. */
819 && MSYMBOL_TYPE (&msymbol
[hi
]) != want_type
820 && MSYMBOL_TYPE (&msymbol
[hi
- 1]) == want_type
821 && (MSYMBOL_SIZE (&msymbol
[hi
])
822 == MSYMBOL_SIZE (&msymbol
[hi
- 1]))
823 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
824 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1]))
825 && (MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
])
826 == MSYMBOL_OBJ_SECTION (objfile
, &msymbol
[hi
- 1])))
832 /* If the minimal symbol has a zero size, save it
833 but keep scanning backwards looking for one with
834 a non-zero size. A zero size may mean that the
835 symbol isn't an object or function (e.g. a
836 label), or it may just mean that the size was not
838 if (MSYMBOL_SIZE (&msymbol
[hi
]) == 0)
840 if (best_zero_sized
== -1)
841 best_zero_sized
= hi
;
846 /* If we are past the end of the current symbol, try
847 the previous symbol if it has a larger overlapping
848 size. This happens on i686-pc-linux-gnu with glibc;
849 the nocancel variants of system calls are inside
850 the cancellable variants, but both have sizes. */
852 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
853 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
854 + MSYMBOL_SIZE (&msymbol
[hi
]))
855 && pc
< (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
- 1])
856 + MSYMBOL_SIZE (&msymbol
[hi
- 1])))
862 /* Otherwise, this symbol must be as good as we're going
867 /* If HI has a zero size, and best_zero_sized is set,
868 then we had two or more zero-sized symbols; prefer
869 the first one we found (which may have a higher
870 address). Also, if we ran off the end, be sure
872 if (best_zero_sized
!= -1
873 && (hi
< 0 || MSYMBOL_SIZE (&msymbol
[hi
]) == 0))
874 hi
= best_zero_sized
;
876 /* If the minimal symbol has a non-zero size, and this
877 PC appears to be outside the symbol's contents, then
878 refuse to use this symbol. If we found a zero-sized
879 symbol with an address greater than this symbol's,
880 use that instead. We assume that if symbols have
881 specified sizes, they do not overlap. */
884 && MSYMBOL_SIZE (&msymbol
[hi
]) != 0
885 && pc
>= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
])
886 + MSYMBOL_SIZE (&msymbol
[hi
])))
888 if (best_zero_sized
!= -1)
889 hi
= best_zero_sized
;
891 /* Go on to the next object file. */
895 /* The minimal symbol indexed by hi now is the best one in this
896 objfile's minimal symbol table. See if it is the best one
900 && ((best_symbol
== NULL
) ||
901 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol
) <
902 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol
[hi
]))))
904 best_symbol
= &msymbol
[hi
];
905 best_objfile
= objfile
;
911 result
.minsym
= best_symbol
;
912 result
.objfile
= best_objfile
;
918 struct bound_minimal_symbol
919 lookup_minimal_symbol_by_pc (CORE_ADDR pc
)
921 return lookup_minimal_symbol_by_pc_section (pc
, NULL
);
924 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
927 in_gnu_ifunc_stub (CORE_ADDR pc
)
929 bound_minimal_symbol msymbol
930 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
931 lookup_msym_prefer::GNU_IFUNC
);
932 return msymbol
.minsym
&& MSYMBOL_TYPE (msymbol
.minsym
) == mst_text_gnu_ifunc
;
935 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
938 stub_gnu_ifunc_resolve_addr (struct gdbarch
*gdbarch
, CORE_ADDR pc
)
940 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
941 "the ELF support compiled in."),
942 paddress (gdbarch
, pc
));
945 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
948 stub_gnu_ifunc_resolve_name (const char *function_name
,
949 CORE_ADDR
*function_address_p
)
951 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
952 "the ELF support compiled in."),
956 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
959 stub_gnu_ifunc_resolver_stop (struct breakpoint
*b
)
961 internal_error (__FILE__
, __LINE__
,
962 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
965 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
968 stub_gnu_ifunc_resolver_return_stop (struct breakpoint
*b
)
970 internal_error (__FILE__
, __LINE__
,
971 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
974 /* See elf_gnu_ifunc_fns for its real implementation. */
976 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns
=
978 stub_gnu_ifunc_resolve_addr
,
979 stub_gnu_ifunc_resolve_name
,
980 stub_gnu_ifunc_resolver_stop
,
981 stub_gnu_ifunc_resolver_return_stop
,
984 /* A placeholder for &elf_gnu_ifunc_fns. */
986 const struct gnu_ifunc_fns
*gnu_ifunc_fns_p
= &stub_gnu_ifunc_fns
;
990 /* Return leading symbol character for a BFD. If BFD is NULL,
991 return the leading symbol character from the main objfile. */
994 get_symbol_leading_char (bfd
*abfd
)
997 return bfd_get_symbol_leading_char (abfd
);
998 if (symfile_objfile
!= NULL
&& symfile_objfile
->obfd
!= NULL
)
999 return bfd_get_symbol_leading_char (symfile_objfile
->obfd
);
1003 /* See minsyms.h. */
1005 minimal_symbol_reader::minimal_symbol_reader (struct objfile
*obj
)
1007 m_msym_bunch (NULL
),
1008 /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the
1009 first call to save a minimal symbol to allocate the memory for
1011 m_msym_bunch_index (BUNCH_SIZE
),
1016 /* Discard the currently collected minimal symbols, if any. If we wish
1017 to save them for later use, we must have already copied them somewhere
1018 else before calling this function. */
1020 minimal_symbol_reader::~minimal_symbol_reader ()
1022 struct msym_bunch
*next
;
1024 while (m_msym_bunch
!= NULL
)
1026 next
= m_msym_bunch
->next
;
1027 xfree (m_msym_bunch
);
1028 m_msym_bunch
= next
;
1032 /* See minsyms.h. */
1035 minimal_symbol_reader::record (const char *name
, CORE_ADDR address
,
1036 enum minimal_symbol_type ms_type
)
1043 case mst_text_gnu_ifunc
:
1045 case mst_solib_trampoline
:
1046 section
= SECT_OFF_TEXT (m_objfile
);
1049 case mst_data_gnu_ifunc
:
1051 section
= SECT_OFF_DATA (m_objfile
);
1055 section
= SECT_OFF_BSS (m_objfile
);
1061 record_with_info (name
, address
, ms_type
, section
);
1064 /* Convert an enumerator of type minimal_symbol_type to its string
1068 mst_str (minimal_symbol_type t
)
1070 #define MST_TO_STR(x) case x: return #x;
1073 MST_TO_STR (mst_unknown
);
1074 MST_TO_STR (mst_text
);
1075 MST_TO_STR (mst_text_gnu_ifunc
);
1076 MST_TO_STR (mst_slot_got_plt
);
1077 MST_TO_STR (mst_data
);
1078 MST_TO_STR (mst_bss
);
1079 MST_TO_STR (mst_abs
);
1080 MST_TO_STR (mst_solib_trampoline
);
1081 MST_TO_STR (mst_file_text
);
1082 MST_TO_STR (mst_file_data
);
1083 MST_TO_STR (mst_file_bss
);
1091 /* See minsyms.h. */
1093 struct minimal_symbol
*
1094 minimal_symbol_reader::record_full (gdb::string_view name
,
1095 bool copy_name
, CORE_ADDR address
,
1096 enum minimal_symbol_type ms_type
,
1099 struct msym_bunch
*newobj
;
1100 struct minimal_symbol
*msymbol
;
1102 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1103 the minimal symbols, because if there is also another symbol
1104 at the same address (e.g. the first function of the file),
1105 lookup_minimal_symbol_by_pc would have no way of getting the
1107 if (ms_type
== mst_file_text
&& name
[0] == 'g'
1108 && (name
== GCC_COMPILED_FLAG_SYMBOL
1109 || name
== GCC2_COMPILED_FLAG_SYMBOL
))
1112 /* It's safe to strip the leading char here once, since the name
1113 is also stored stripped in the minimal symbol table. */
1114 if (name
[0] == get_symbol_leading_char (m_objfile
->obfd
))
1115 name
= name
.substr (1);
1117 if (ms_type
== mst_file_text
&& startswith (name
, "__gnu_compiled"))
1120 if (symtab_create_debug
>= 2)
1121 printf_unfiltered ("Recording minsym: %-21s %18s %4d %.*s\n",
1122 mst_str (ms_type
), hex_string (address
), section
,
1123 (int) name
.size (), name
.data ());
1125 if (m_msym_bunch_index
== BUNCH_SIZE
)
1127 newobj
= XCNEW (struct msym_bunch
);
1128 m_msym_bunch_index
= 0;
1129 newobj
->next
= m_msym_bunch
;
1130 m_msym_bunch
= newobj
;
1132 msymbol
= &m_msym_bunch
->contents
[m_msym_bunch_index
];
1133 symbol_set_language (msymbol
, language_auto
,
1134 &m_objfile
->per_bfd
->storage_obstack
);
1137 msymbol
->name
= obstack_strndup (&m_objfile
->per_bfd
->storage_obstack
,
1138 name
.data (), name
.size ());
1140 msymbol
->name
= name
.data ();
1142 SET_MSYMBOL_VALUE_ADDRESS (msymbol
, address
);
1143 MSYMBOL_SECTION (msymbol
) = section
;
1145 MSYMBOL_TYPE (msymbol
) = ms_type
;
1147 /* If we already read minimal symbols for this objfile, then don't
1148 ever allocate a new one. */
1149 if (!m_objfile
->per_bfd
->minsyms_read
)
1151 m_msym_bunch_index
++;
1152 m_objfile
->per_bfd
->n_minsyms
++;
1158 /* Compare two minimal symbols by address and return true if FN1's address
1159 is less than FN2's, so that we sort into unsigned numeric order.
1160 Within groups with the same address, sort by name. */
1163 minimal_symbol_is_less_than (const minimal_symbol
&fn1
,
1164 const minimal_symbol
&fn2
)
1166 if (MSYMBOL_VALUE_RAW_ADDRESS (&fn1
) < MSYMBOL_VALUE_RAW_ADDRESS (&fn2
))
1168 return true; /* addr 1 is less than addr 2. */
1170 else if (MSYMBOL_VALUE_RAW_ADDRESS (&fn1
) > MSYMBOL_VALUE_RAW_ADDRESS (&fn2
))
1172 return false; /* addr 1 is greater than addr 2. */
1175 /* addrs are equal: sort by name */
1177 const char *name1
= fn1
.linkage_name ();
1178 const char *name2
= fn2
.linkage_name ();
1180 if (name1
&& name2
) /* both have names */
1181 return strcmp (name1
, name2
) < 0;
1183 return true; /* fn1 has no name, so it is "less". */
1184 else if (name1
) /* fn2 has no name, so it is "less". */
1187 return false; /* Neither has a name, so they're equal. */
1191 /* Compact duplicate entries out of a minimal symbol table by walking
1192 through the table and compacting out entries with duplicate addresses
1193 and matching names. Return the number of entries remaining.
1195 On entry, the table resides between msymbol[0] and msymbol[mcount].
1196 On exit, it resides between msymbol[0] and msymbol[result_count].
1198 When files contain multiple sources of symbol information, it is
1199 possible for the minimal symbol table to contain many duplicate entries.
1200 As an example, SVR4 systems use ELF formatted object files, which
1201 usually contain at least two different types of symbol tables (a
1202 standard ELF one and a smaller dynamic linking table), as well as
1203 DWARF debugging information for files compiled with -g.
1205 Without compacting, the minimal symbol table for gdb itself contains
1206 over a 1000 duplicates, about a third of the total table size. Aside
1207 from the potential trap of not noticing that two successive entries
1208 identify the same location, this duplication impacts the time required
1209 to linearly scan the table, which is done in a number of places. So we
1210 just do one linear scan here and toss out the duplicates.
1212 Since the different sources of information for each symbol may
1213 have different levels of "completeness", we may have duplicates
1214 that have one entry with type "mst_unknown" and the other with a
1215 known type. So if the one we are leaving alone has type mst_unknown,
1216 overwrite its type with the type from the one we are compacting out. */
1219 compact_minimal_symbols (struct minimal_symbol
*msymbol
, int mcount
,
1220 struct objfile
*objfile
)
1222 struct minimal_symbol
*copyfrom
;
1223 struct minimal_symbol
*copyto
;
1227 copyfrom
= copyto
= msymbol
;
1228 while (copyfrom
< msymbol
+ mcount
- 1)
1230 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom
)
1231 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom
+ 1))
1232 && MSYMBOL_SECTION (copyfrom
) == MSYMBOL_SECTION (copyfrom
+ 1)
1233 && strcmp (copyfrom
->linkage_name (),
1234 (copyfrom
+ 1)->linkage_name ()) == 0)
1236 if (MSYMBOL_TYPE ((copyfrom
+ 1)) == mst_unknown
)
1238 MSYMBOL_TYPE ((copyfrom
+ 1)) = MSYMBOL_TYPE (copyfrom
);
1243 *copyto
++ = *copyfrom
++;
1245 *copyto
++ = *copyfrom
++;
1246 mcount
= copyto
- msymbol
;
1252 clear_minimal_symbol_hash_tables (struct objfile
*objfile
)
1254 for (size_t 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;
1261 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1262 after compacting or sorting the table since the entries move around
1263 thus causing the internal minimal_symbol pointers to become jumbled. */
1266 build_minimal_symbol_hash_tables (struct objfile
*objfile
)
1269 struct minimal_symbol
*msym
;
1271 /* (Re)insert the actual entries. */
1272 for ((i
= objfile
->per_bfd
->minimal_symbol_count
,
1273 msym
= objfile
->per_bfd
->msymbols
.get ());
1277 msym
->hash_next
= 0;
1278 add_minsym_to_hash_table (msym
, objfile
->per_bfd
->msymbol_hash
);
1280 msym
->demangled_hash_next
= 0;
1281 if (msym
->search_name () != msym
->linkage_name ())
1282 add_minsym_to_demangled_hash_table (msym
, objfile
);
1286 /* Add the minimal symbols in the existing bunches to the objfile's official
1287 minimal symbol table. In most cases there is no minimal symbol table yet
1288 for this objfile, and the existing bunches are used to create one. Once
1289 in a while (for shared libraries for example), we add symbols (e.g. common
1290 symbols) to an existing objfile. */
1293 minimal_symbol_reader::install ()
1296 struct msym_bunch
*bunch
;
1297 struct minimal_symbol
*msymbols
;
1300 if (m_objfile
->per_bfd
->minsyms_read
)
1303 if (m_msym_count
> 0)
1305 if (symtab_create_debug
)
1307 fprintf_unfiltered (gdb_stdlog
,
1308 "Installing %d minimal symbols of objfile %s.\n",
1309 m_msym_count
, objfile_name (m_objfile
));
1312 /* Allocate enough space, into which we will gather the bunches
1313 of new and existing minimal symbols, sort them, and then
1314 compact out the duplicate entries. Once we have a final
1315 table, we will give back the excess space. */
1317 alloc_count
= m_msym_count
+ m_objfile
->per_bfd
->minimal_symbol_count
;
1318 gdb::unique_xmalloc_ptr
<minimal_symbol
>
1319 msym_holder (XNEWVEC (minimal_symbol
, alloc_count
));
1320 msymbols
= msym_holder
.get ();
1322 /* Copy in the existing minimal symbols, if there are any. */
1324 if (m_objfile
->per_bfd
->minimal_symbol_count
)
1325 memcpy (msymbols
, m_objfile
->per_bfd
->msymbols
.get (),
1326 m_objfile
->per_bfd
->minimal_symbol_count
1327 * sizeof (struct minimal_symbol
));
1329 /* Walk through the list of minimal symbol bunches, adding each symbol
1330 to the new contiguous array of symbols. Note that we start with the
1331 current, possibly partially filled bunch (thus we use the current
1332 msym_bunch_index for the first bunch we copy over), and thereafter
1333 each bunch is full. */
1335 mcount
= m_objfile
->per_bfd
->minimal_symbol_count
;
1337 for (bunch
= m_msym_bunch
; bunch
!= NULL
; bunch
= bunch
->next
)
1339 memcpy (&msymbols
[mcount
], &bunch
->contents
[0],
1340 m_msym_bunch_index
* sizeof (struct minimal_symbol
));
1341 mcount
+= m_msym_bunch_index
;
1342 m_msym_bunch_index
= BUNCH_SIZE
;
1345 /* Sort the minimal symbols by address. */
1347 std::sort (msymbols
, msymbols
+ mcount
, minimal_symbol_is_less_than
);
1349 /* Compact out any duplicates, and free up whatever space we are
1352 mcount
= compact_minimal_symbols (msymbols
, mcount
, m_objfile
);
1353 msym_holder
.reset (XRESIZEVEC (struct minimal_symbol
,
1354 msym_holder
.release (),
1357 /* Attach the minimal symbol table to the specified objfile.
1358 The strings themselves are also located in the storage_obstack
1361 if (m_objfile
->per_bfd
->minimal_symbol_count
!= 0)
1362 clear_minimal_symbol_hash_tables (m_objfile
);
1364 m_objfile
->per_bfd
->minimal_symbol_count
= mcount
;
1365 m_objfile
->per_bfd
->msymbols
= std::move (msym_holder
);
1368 /* Mutex that is used when modifying or accessing the demangled
1370 std::mutex demangled_mutex
;
1373 msymbols
= m_objfile
->per_bfd
->msymbols
.get ();
1374 gdb::parallel_for_each
1375 (&msymbols
[0], &msymbols
[mcount
],
1376 [&] (minimal_symbol
*start
, minimal_symbol
*end
)
1378 for (minimal_symbol
*msym
= start
; msym
< end
; ++msym
)
1380 if (!msym
->name_set
)
1382 /* This will be freed later, by symbol_set_names. */
1383 char *demangled_name
1384 = symbol_find_demangled_name (msym
, msym
->name
);
1385 symbol_set_demangled_name
1386 (msym
, demangled_name
,
1387 &m_objfile
->per_bfd
->storage_obstack
);
1392 /* To limit how long we hold the lock, we only acquire it here
1393 and not while we demangle the names above. */
1395 std::lock_guard
<std::mutex
> guard (demangled_mutex
);
1397 for (minimal_symbol
*msym
= start
; msym
< end
; ++msym
)
1399 symbol_set_names (msym
, msym
->name
, false,
1400 m_objfile
->per_bfd
);
1405 build_minimal_symbol_hash_tables (m_objfile
);
1409 /* Check if PC is in a shared library trampoline code stub.
1410 Return minimal symbol for the trampoline entry or NULL if PC is not
1411 in a trampoline code stub. */
1413 static struct minimal_symbol
*
1414 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc
)
1416 bound_minimal_symbol msymbol
1417 = lookup_minimal_symbol_by_pc_section (pc
, NULL
,
1418 lookup_msym_prefer::TRAMPOLINE
);
1420 if (msymbol
.minsym
!= NULL
1421 && MSYMBOL_TYPE (msymbol
.minsym
) == mst_solib_trampoline
)
1422 return msymbol
.minsym
;
1426 /* If PC is in a shared library trampoline code stub, return the
1427 address of the `real' function belonging to the stub.
1428 Return 0 if PC is not in a trampoline code stub or if the real
1429 function is not found in the minimal symbol table.
1431 We may fail to find the right function if a function with the
1432 same name is defined in more than one shared library, but this
1433 is considered bad programming style. We could return 0 if we find
1434 a duplicate function in case this matters someday. */
1437 find_solib_trampoline_target (struct frame_info
*frame
, CORE_ADDR pc
)
1439 struct minimal_symbol
*tsymbol
= lookup_solib_trampoline_symbol_by_pc (pc
);
1441 if (tsymbol
!= NULL
)
1443 for (objfile
*objfile
: current_program_space
->objfiles ())
1445 for (minimal_symbol
*msymbol
: objfile
->msymbols ())
1447 /* Also handle minimal symbols pointing to function
1449 if ((MSYMBOL_TYPE (msymbol
) == mst_text
1450 || MSYMBOL_TYPE (msymbol
) == mst_text_gnu_ifunc
1451 || MSYMBOL_TYPE (msymbol
) == mst_data
1452 || MSYMBOL_TYPE (msymbol
) == mst_data_gnu_ifunc
)
1453 && strcmp (msymbol
->linkage_name (),
1454 tsymbol
->linkage_name ()) == 0)
1458 /* Ignore data symbols that are not function
1460 if (msymbol_is_function (objfile
, msymbol
, &func
))
1469 /* See minsyms.h. */
1472 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym
)
1475 struct obj_section
*obj_section
;
1477 struct minimal_symbol
*iter
, *msymbol
;
1479 gdb_assert (minsym
.minsym
!= NULL
);
1481 /* If the minimal symbol has a size, use it. Otherwise use the
1482 lesser of the next minimal symbol in the same section, or the end
1483 of the section, as the end of the function. */
1485 if (MSYMBOL_SIZE (minsym
.minsym
) != 0)
1486 return BMSYMBOL_VALUE_ADDRESS (minsym
) + MSYMBOL_SIZE (minsym
.minsym
);
1488 /* Step over other symbols at this same address, and symbols in
1489 other sections, to find the next symbol in this section with a
1490 different address. */
1492 struct minimal_symbol
*past_the_end
1493 = (minsym
.objfile
->per_bfd
->msymbols
.get ()
1494 + minsym
.objfile
->per_bfd
->minimal_symbol_count
);
1495 msymbol
= minsym
.minsym
;
1496 section
= MSYMBOL_SECTION (msymbol
);
1497 for (iter
= msymbol
+ 1; iter
!= past_the_end
; ++iter
)
1499 if ((MSYMBOL_VALUE_RAW_ADDRESS (iter
)
1500 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol
))
1501 && MSYMBOL_SECTION (iter
) == section
)
1505 obj_section
= MSYMBOL_OBJ_SECTION (minsym
.objfile
, minsym
.minsym
);
1506 if (iter
!= past_the_end
1507 && (MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, iter
)
1508 < obj_section_endaddr (obj_section
)))
1509 result
= MSYMBOL_VALUE_ADDRESS (minsym
.objfile
, iter
);
1511 /* We got the start address from the last msymbol in the objfile.
1512 So the end address is the end of the section. */
1513 result
= obj_section_endaddr (obj_section
);