1 /* GDB routines for manipulating the minimal symbol tables.
2 Copyright (C) 1992-2016 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"
55 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
56 At the end, copy them all into one newly allocated location on an objfile's
57 per-BFD storage obstack. */
59 #define BUNCH_SIZE 127
63 struct msym_bunch *next;
64 struct minimal_symbol contents[BUNCH_SIZE];
67 /* Bunch currently being filled up.
68 The next field points to chain of filled bunches. */
70 static struct msym_bunch *msym_bunch;
72 /* Number of slots filled in current bunch. */
74 static int msym_bunch_index;
76 /* Total number of minimal symbols recorded so far for the objfile. */
78 static int msym_count;
83 msymbol_hash_iw (const char *string)
85 unsigned int hash = 0;
87 while (*string && *string != '(')
89 string = skip_spaces_const (string);
90 if (*string && *string != '(')
92 hash = SYMBOL_HASH_NEXT (hash, *string);
102 msymbol_hash (const char *string)
104 unsigned int hash = 0;
106 for (; *string; ++string)
107 hash = SYMBOL_HASH_NEXT (hash, *string);
111 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */
113 add_minsym_to_hash_table (struct minimal_symbol *sym,
114 struct minimal_symbol **table)
116 if (sym->hash_next == NULL)
119 = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
121 sym->hash_next = table[hash];
126 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
129 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
130 struct minimal_symbol **table)
132 if (sym->demangled_hash_next == NULL)
134 unsigned int hash = msymbol_hash_iw (MSYMBOL_SEARCH_NAME (sym))
135 % MINIMAL_SYMBOL_HASH_SIZE;
137 sym->demangled_hash_next = table[hash];
142 /* Look through all the current minimal symbol tables and find the
143 first minimal symbol that matches NAME. If OBJF is non-NULL, limit
144 the search to that objfile. If SFILE is non-NULL, the only file-scope
145 symbols considered will be from that source file (global symbols are
146 still preferred). Returns a pointer to the minimal symbol that
147 matches, or NULL if no match is found.
149 Note: One instance where there may be duplicate minimal symbols with
150 the same name is when the symbol tables for a shared library and the
151 symbol tables for an executable contain global symbols with the same
152 names (the dynamic linker deals with the duplication).
154 It's also possible to have minimal symbols with different mangled
155 names, but identical demangled names. For example, the GNU C++ v3
156 ABI requires the generation of two (or perhaps three) copies of
157 constructor functions --- "in-charge", "not-in-charge", and
158 "allocate" copies; destructors may be duplicated as well.
159 Obviously, there must be distinct mangled names for each of these,
160 but the demangled names are all the same: S::S or S::~S. */
162 struct bound_minimal_symbol
163 lookup_minimal_symbol (const char *name, const char *sfile,
164 struct objfile *objf)
166 struct objfile *objfile;
167 struct bound_minimal_symbol found_symbol = { NULL, NULL };
168 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
169 struct bound_minimal_symbol trampoline_symbol = { NULL, NULL };
171 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
172 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
174 int needtofreename = 0;
175 const char *modified_name;
178 sfile = lbasename (sfile);
180 /* For C++, canonicalize the input name. */
181 modified_name = name;
182 if (current_language->la_language == language_cplus)
184 char *cname = cp_canonicalize_string (name);
188 modified_name = cname;
193 for (objfile = object_files;
194 objfile != NULL && found_symbol.minsym == NULL;
195 objfile = objfile->next)
197 struct minimal_symbol *msymbol;
199 if (objf == NULL || objf == objfile
200 || objf == objfile->separate_debug_objfile_backlink)
202 /* Do two passes: the first over the ordinary hash table,
203 and the second over the demangled hash table. */
206 if (symbol_lookup_debug)
208 fprintf_unfiltered (gdb_stdlog,
209 "lookup_minimal_symbol (%s, %s, %s)\n",
210 name, sfile != NULL ? sfile : "NULL",
211 objfile_debug_name (objfile));
214 for (pass = 1; pass <= 2 && found_symbol.minsym == NULL; pass++)
216 /* Select hash list according to pass. */
218 msymbol = objfile->per_bfd->msymbol_hash[hash];
220 msymbol = objfile->per_bfd->msymbol_demangled_hash[dem_hash];
222 while (msymbol != NULL && found_symbol.minsym == NULL)
228 int (*cmp) (const char *, const char *);
230 cmp = (case_sensitivity == case_sensitive_on
231 ? strcmp : strcasecmp);
232 match = cmp (MSYMBOL_LINKAGE_NAME (msymbol),
237 /* The function respects CASE_SENSITIVITY. */
238 match = MSYMBOL_MATCHES_SEARCH_NAME (msymbol,
244 switch (MSYMBOL_TYPE (msymbol))
250 || filename_cmp (msymbol->filename, sfile) == 0)
252 found_file_symbol.minsym = msymbol;
253 found_file_symbol.objfile = objfile;
257 case mst_solib_trampoline:
259 /* If a trampoline symbol is found, we prefer to
260 keep looking for the *real* symbol. If the
261 actual symbol is not found, then we'll use the
263 if (trampoline_symbol.minsym == NULL)
265 trampoline_symbol.minsym = msymbol;
266 trampoline_symbol.objfile = objfile;
272 found_symbol.minsym = msymbol;
273 found_symbol.objfile = objfile;
278 /* Find the next symbol on the hash chain. */
280 msymbol = msymbol->hash_next;
282 msymbol = msymbol->demangled_hash_next;
289 xfree ((void *) modified_name);
291 /* External symbols are best. */
292 if (found_symbol.minsym != NULL)
294 if (symbol_lookup_debug)
296 fprintf_unfiltered (gdb_stdlog,
297 "lookup_minimal_symbol (...) = %s"
299 host_address_to_string (found_symbol.minsym));
304 /* File-local symbols are next best. */
305 if (found_file_symbol.minsym != NULL)
307 if (symbol_lookup_debug)
309 fprintf_unfiltered (gdb_stdlog,
310 "lookup_minimal_symbol (...) = %s"
312 host_address_to_string
313 (found_file_symbol.minsym));
315 return found_file_symbol;
318 /* Symbols for shared library trampolines are next best. */
319 if (symbol_lookup_debug)
321 fprintf_unfiltered (gdb_stdlog,
322 "lookup_minimal_symbol (...) = %s%s\n",
323 trampoline_symbol.minsym != NULL
324 ? host_address_to_string (trampoline_symbol.minsym)
326 trampoline_symbol.minsym != NULL
327 ? " (trampoline)" : "");
329 return trampoline_symbol;
334 struct bound_minimal_symbol
335 lookup_bound_minimal_symbol (const char *name)
337 return lookup_minimal_symbol (name, NULL, NULL);
340 /* See common/symbol.h. */
343 find_minimal_symbol_address (const char *name, CORE_ADDR *addr,
344 struct objfile *objfile)
346 struct bound_minimal_symbol sym
347 = lookup_minimal_symbol (name, NULL, objfile);
349 if (sym.minsym != NULL)
350 *addr = BMSYMBOL_VALUE_ADDRESS (sym);
352 return sym.minsym == NULL;
358 iterate_over_minimal_symbols (struct objfile *objf, const char *name,
359 void (*callback) (struct minimal_symbol *,
364 struct minimal_symbol *iter;
365 int (*cmp) (const char *, const char *);
367 /* The first pass is over the ordinary hash table. */
368 hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
369 iter = objf->per_bfd->msymbol_hash[hash];
370 cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);
373 if (cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
374 (*callback) (iter, user_data);
375 iter = iter->hash_next;
378 /* The second pass is over the demangled table. */
379 hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
380 iter = objf->per_bfd->msymbol_demangled_hash[hash];
383 if (MSYMBOL_MATCHES_SEARCH_NAME (iter, name))
384 (*callback) (iter, user_data);
385 iter = iter->demangled_hash_next;
391 struct bound_minimal_symbol
392 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
394 struct objfile *objfile;
395 struct minimal_symbol *msymbol;
396 struct bound_minimal_symbol found_symbol = { NULL, NULL };
397 struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
399 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
401 for (objfile = object_files;
402 objfile != NULL && found_symbol.minsym == NULL;
403 objfile = objfile->next)
405 if (objf == NULL || objf == objfile
406 || objf == objfile->separate_debug_objfile_backlink)
408 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
409 msymbol != NULL && found_symbol.minsym == NULL;
410 msymbol = msymbol->hash_next)
412 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
413 (MSYMBOL_TYPE (msymbol) == mst_text
414 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
415 || MSYMBOL_TYPE (msymbol) == mst_file_text))
417 switch (MSYMBOL_TYPE (msymbol))
420 found_file_symbol.minsym = msymbol;
421 found_file_symbol.objfile = objfile;
424 found_symbol.minsym = msymbol;
425 found_symbol.objfile = objfile;
432 /* External symbols are best. */
433 if (found_symbol.minsym)
436 /* File-local symbols are next best. */
437 return found_file_symbol;
442 struct minimal_symbol *
443 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
444 struct objfile *objf)
446 struct objfile *objfile;
447 struct minimal_symbol *msymbol;
449 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
451 for (objfile = object_files;
453 objfile = objfile->next)
455 if (objf == NULL || objf == objfile
456 || objf == objfile->separate_debug_objfile_backlink)
458 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
460 msymbol = msymbol->hash_next)
462 if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
463 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
474 struct bound_minimal_symbol
475 lookup_minimal_symbol_solib_trampoline (const char *name,
476 struct objfile *objf)
478 struct objfile *objfile;
479 struct minimal_symbol *msymbol;
480 struct bound_minimal_symbol found_symbol = { NULL, NULL };
482 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
484 for (objfile = object_files;
486 objfile = objfile->next)
488 if (objf == NULL || objf == objfile
489 || objf == objfile->separate_debug_objfile_backlink)
491 for (msymbol = objfile->per_bfd->msymbol_hash[hash];
493 msymbol = msymbol->hash_next)
495 if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
496 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
498 found_symbol.objfile = objfile;
499 found_symbol.minsym = msymbol;
509 /* A helper function that makes *PC section-relative. This searches
510 the sections of OBJFILE and if *PC is in a section, it subtracts
511 the section offset and returns true. Otherwise it returns
515 frob_address (struct objfile *objfile, CORE_ADDR *pc)
517 struct obj_section *iter;
519 ALL_OBJFILE_OSECTIONS (objfile, iter)
521 if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
523 *pc -= obj_section_offset (iter);
531 /* Search through the minimal symbol table for each objfile and find
532 the symbol whose address is the largest address that is still less
533 than or equal to PC, and matches SECTION (which is not NULL).
534 Returns a pointer to the minimal symbol if such a symbol is found,
535 or NULL if PC is not in a suitable range.
536 Note that we need to look through ALL the minimal symbol tables
537 before deciding on the symbol that comes closest to the specified PC.
538 This is because objfiles can overlap, for example objfile A has .text
539 at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
542 If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
543 there are text and trampoline symbols at the same address.
544 Otherwise prefer mst_text symbols. */
546 static struct bound_minimal_symbol
547 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc_in,
548 struct obj_section *section,
554 struct objfile *objfile;
555 struct minimal_symbol *msymbol;
556 struct minimal_symbol *best_symbol = NULL;
557 struct objfile *best_objfile = NULL;
558 struct bound_minimal_symbol result;
559 enum minimal_symbol_type want_type, other_type;
561 want_type = want_trampoline ? mst_solib_trampoline : mst_text;
562 other_type = want_trampoline ? mst_text : mst_solib_trampoline;
564 /* We can not require the symbol found to be in section, because
565 e.g. IRIX 6.5 mdebug relies on this code returning an absolute
566 symbol - but find_pc_section won't return an absolute section and
567 hence the code below would skip over absolute symbols. We can
568 still take advantage of the call to find_pc_section, though - the
569 object file still must match. In case we have separate debug
570 files, search both the file and its separate debug file. There's
571 no telling which one will have the minimal symbols. */
573 gdb_assert (section != NULL);
575 for (objfile = section->objfile;
577 objfile = objfile_separate_debug_iterate (section->objfile, objfile))
579 CORE_ADDR pc = pc_in;
581 /* If this objfile has a minimal symbol table, go search it using
582 a binary search. Note that a minimal symbol table always consists
583 of at least two symbols, a "real" symbol and the terminating
584 "null symbol". If there are no real symbols, then there is no
585 minimal symbol table at all. */
587 if (objfile->per_bfd->minimal_symbol_count > 0)
589 int best_zero_sized = -1;
591 msymbol = objfile->per_bfd->msymbols;
593 hi = objfile->per_bfd->minimal_symbol_count - 1;
595 /* This code assumes that the minimal symbols are sorted by
596 ascending address values. If the pc value is greater than or
597 equal to the first symbol's address, then some symbol in this
598 minimal symbol table is a suitable candidate for being the
599 "best" symbol. This includes the last real symbol, for cases
600 where the pc value is larger than any address in this vector.
602 By iterating until the address associated with the current
603 hi index (the endpoint of the test interval) is less than
604 or equal to the desired pc value, we accomplish two things:
605 (1) the case where the pc value is larger than any minimal
606 symbol address is trivially solved, (2) the address associated
607 with the hi index is always the one we want when the interation
608 terminates. In essence, we are iterating the test interval
609 down until the pc value is pushed out of it from the high end.
611 Warning: this code is trickier than it would appear at first. */
613 if (frob_address (objfile, &pc)
614 && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
616 while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
618 /* pc is still strictly less than highest address. */
619 /* Note "new" will always be >= lo. */
620 newobj = (lo + hi) / 2;
621 if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
632 /* If we have multiple symbols at the same address, we want
633 hi to point to the last one. That way we can find the
634 right symbol if it has an index greater than hi. */
635 while (hi < objfile->per_bfd->minimal_symbol_count - 1
636 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
637 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
640 /* Skip various undesirable symbols. */
643 /* Skip any absolute symbols. This is apparently
644 what adb and dbx do, and is needed for the CM-5.
645 There are two known possible problems: (1) on
646 ELF, apparently end, edata, etc. are absolute.
647 Not sure ignoring them here is a big deal, but if
648 we want to use them, the fix would go in
649 elfread.c. (2) I think shared library entry
650 points on the NeXT are absolute. If we want
651 special handling for this it probably should be
652 triggered by a special mst_abs_or_lib or some
655 if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
661 /* If SECTION was specified, skip any symbol from
664 /* Some types of debug info, such as COFF,
665 don't fill the bfd_section member, so don't
666 throw away symbols on those platforms. */
667 && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
668 && (!matching_obj_sections
669 (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
676 /* If we are looking for a trampoline and this is a
677 text symbol, or the other way around, check the
678 preceding symbol too. If they are otherwise
679 identical prefer that one. */
681 && MSYMBOL_TYPE (&msymbol[hi]) == other_type
682 && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
683 && (MSYMBOL_SIZE (&msymbol[hi])
684 == MSYMBOL_SIZE (&msymbol[hi - 1]))
685 && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
686 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
687 && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
688 == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
694 /* If the minimal symbol has a zero size, save it
695 but keep scanning backwards looking for one with
696 a non-zero size. A zero size may mean that the
697 symbol isn't an object or function (e.g. a
698 label), or it may just mean that the size was not
700 if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
702 if (best_zero_sized == -1)
703 best_zero_sized = hi;
708 /* If we are past the end of the current symbol, try
709 the previous symbol if it has a larger overlapping
710 size. This happens on i686-pc-linux-gnu with glibc;
711 the nocancel variants of system calls are inside
712 the cancellable variants, but both have sizes. */
714 && MSYMBOL_SIZE (&msymbol[hi]) != 0
715 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
716 + MSYMBOL_SIZE (&msymbol[hi]))
717 && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
718 + MSYMBOL_SIZE (&msymbol[hi - 1])))
724 /* Otherwise, this symbol must be as good as we're going
729 /* If HI has a zero size, and best_zero_sized is set,
730 then we had two or more zero-sized symbols; prefer
731 the first one we found (which may have a higher
732 address). Also, if we ran off the end, be sure
734 if (best_zero_sized != -1
735 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
736 hi = best_zero_sized;
738 /* If the minimal symbol has a non-zero size, and this
739 PC appears to be outside the symbol's contents, then
740 refuse to use this symbol. If we found a zero-sized
741 symbol with an address greater than this symbol's,
742 use that instead. We assume that if symbols have
743 specified sizes, they do not overlap. */
746 && MSYMBOL_SIZE (&msymbol[hi]) != 0
747 && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
748 + MSYMBOL_SIZE (&msymbol[hi])))
750 if (best_zero_sized != -1)
751 hi = best_zero_sized;
753 /* Go on to the next object file. */
757 /* The minimal symbol indexed by hi now is the best one in this
758 objfile's minimal symbol table. See if it is the best one
762 && ((best_symbol == NULL) ||
763 (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
764 MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
766 best_symbol = &msymbol[hi];
767 best_objfile = objfile;
773 result.minsym = best_symbol;
774 result.objfile = best_objfile;
778 struct bound_minimal_symbol
779 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
783 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
784 force the section but that (well unless you're doing overlay
785 debugging) always returns NULL making the call somewhat useless. */
786 section = find_pc_section (pc);
789 struct bound_minimal_symbol result;
791 memset (&result, 0, sizeof (result));
795 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
800 struct bound_minimal_symbol
801 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
803 struct obj_section *section = find_pc_section (pc);
807 struct bound_minimal_symbol result;
809 memset (&result, 0, sizeof (result));
812 return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
815 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */
818 in_gnu_ifunc_stub (CORE_ADDR pc)
820 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
822 return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
825 /* See elf_gnu_ifunc_resolve_addr for its real implementation. */
828 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
830 error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
831 "the ELF support compiled in."),
832 paddress (gdbarch, pc));
835 /* See elf_gnu_ifunc_resolve_name for its real implementation. */
838 stub_gnu_ifunc_resolve_name (const char *function_name,
839 CORE_ADDR *function_address_p)
841 error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
842 "the ELF support compiled in."),
846 /* See elf_gnu_ifunc_resolver_stop for its real implementation. */
849 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
851 internal_error (__FILE__, __LINE__,
852 _("elf_gnu_ifunc_resolver_stop cannot be reached."));
855 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */
858 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
860 internal_error (__FILE__, __LINE__,
861 _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
864 /* See elf_gnu_ifunc_fns for its real implementation. */
866 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
868 stub_gnu_ifunc_resolve_addr,
869 stub_gnu_ifunc_resolve_name,
870 stub_gnu_ifunc_resolver_stop,
871 stub_gnu_ifunc_resolver_return_stop,
874 /* A placeholder for &elf_gnu_ifunc_fns. */
876 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
880 struct bound_minimal_symbol
881 lookup_minimal_symbol_and_objfile (const char *name)
883 struct bound_minimal_symbol result;
884 struct objfile *objfile;
885 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
887 ALL_OBJFILES (objfile)
889 struct minimal_symbol *msym;
891 for (msym = objfile->per_bfd->msymbol_hash[hash];
893 msym = msym->hash_next)
895 if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
897 result.minsym = msym;
898 result.objfile = objfile;
904 memset (&result, 0, sizeof (result));
909 /* Return leading symbol character for a BFD. If BFD is NULL,
910 return the leading symbol character from the main objfile. */
913 get_symbol_leading_char (bfd *abfd)
916 return bfd_get_symbol_leading_char (abfd);
917 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
918 return bfd_get_symbol_leading_char (symfile_objfile->obfd);
924 minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj)
929 /* Note that presetting msym_bunch_index to BUNCH_SIZE causes the
930 first call to save a minimal symbol to allocate the memory for
932 msym_bunch_index = BUNCH_SIZE;
935 /* Discard the currently collected minimal symbols, if any. If we wish
936 to save them for later use, we must have already copied them somewhere
937 else before calling this function.
939 FIXME: We could allocate the minimal symbol bunches on their own
940 obstack and then simply blow the obstack away when we are done with
941 it. Is it worth the extra trouble though? */
943 minimal_symbol_reader::~minimal_symbol_reader ()
945 struct msym_bunch *next;
947 while (msym_bunch != NULL)
949 next = msym_bunch->next;
958 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
959 enum minimal_symbol_type ms_type,
960 struct objfile *objfile)
967 case mst_text_gnu_ifunc:
969 case mst_solib_trampoline:
970 section = SECT_OFF_TEXT (objfile);
974 section = SECT_OFF_DATA (objfile);
978 section = SECT_OFF_BSS (objfile);
984 prim_record_minimal_symbol_and_info (name, address, ms_type,
990 struct minimal_symbol *
991 prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
993 enum minimal_symbol_type ms_type,
995 struct objfile *objfile)
997 struct msym_bunch *newobj;
998 struct minimal_symbol *msymbol;
1000 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
1001 the minimal symbols, because if there is also another symbol
1002 at the same address (e.g. the first function of the file),
1003 lookup_minimal_symbol_by_pc would have no way of getting the
1005 if (ms_type == mst_file_text && name[0] == 'g'
1006 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
1007 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
1010 /* It's safe to strip the leading char here once, since the name
1011 is also stored stripped in the minimal symbol table. */
1012 if (name[0] == get_symbol_leading_char (objfile->obfd))
1018 if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
1021 if (msym_bunch_index == BUNCH_SIZE)
1023 newobj = XCNEW (struct msym_bunch);
1024 msym_bunch_index = 0;
1025 newobj->next = msym_bunch;
1026 msym_bunch = newobj;
1028 msymbol = &msym_bunch->contents[msym_bunch_index];
1029 MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
1030 &objfile->per_bfd->storage_obstack);
1031 MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, objfile);
1033 SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1034 MSYMBOL_SECTION (msymbol) = section;
1036 MSYMBOL_TYPE (msymbol) = ms_type;
1037 MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
1038 MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
1039 /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
1040 as it would also set the has_size flag. */
1043 /* The hash pointers must be cleared! If they're not,
1044 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */
1045 msymbol->hash_next = NULL;
1046 msymbol->demangled_hash_next = NULL;
1048 /* If we already read minimal symbols for this objfile, then don't
1049 ever allocate a new one. */
1050 if (!objfile->per_bfd->minsyms_read)
1053 objfile->per_bfd->n_minsyms++;
1059 /* See minsyms.h. */
1061 struct minimal_symbol *
1062 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
1063 enum minimal_symbol_type ms_type,
1065 struct objfile *objfile)
1067 return prim_record_minimal_symbol_full (name, strlen (name), 1,
1072 /* Compare two minimal symbols by address and return a signed result based
1073 on unsigned comparisons, so that we sort into unsigned numeric order.
1074 Within groups with the same address, sort by name. */
1077 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1079 const struct minimal_symbol *fn1;
1080 const struct minimal_symbol *fn2;
1082 fn1 = (const struct minimal_symbol *) fn1p;
1083 fn2 = (const struct minimal_symbol *) fn2p;
1085 if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1087 return (-1); /* addr 1 is less than addr 2. */
1089 else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1091 return (1); /* addr 1 is greater than addr 2. */
1094 /* addrs are equal: sort by name */
1096 const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1097 const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1099 if (name1 && name2) /* both have names */
1100 return strcmp (name1, name2);
1102 return 1; /* fn1 has no name, so it is "less". */
1103 else if (name1) /* fn2 has no name, so it is "less". */
1106 return (0); /* Neither has a name, so they're equal. */
1110 /* Compact duplicate entries out of a minimal symbol table by walking
1111 through the table and compacting out entries with duplicate addresses
1112 and matching names. Return the number of entries remaining.
1114 On entry, the table resides between msymbol[0] and msymbol[mcount].
1115 On exit, it resides between msymbol[0] and msymbol[result_count].
1117 When files contain multiple sources of symbol information, it is
1118 possible for the minimal symbol table to contain many duplicate entries.
1119 As an example, SVR4 systems use ELF formatted object files, which
1120 usually contain at least two different types of symbol tables (a
1121 standard ELF one and a smaller dynamic linking table), as well as
1122 DWARF debugging information for files compiled with -g.
1124 Without compacting, the minimal symbol table for gdb itself contains
1125 over a 1000 duplicates, about a third of the total table size. Aside
1126 from the potential trap of not noticing that two successive entries
1127 identify the same location, this duplication impacts the time required
1128 to linearly scan the table, which is done in a number of places. So we
1129 just do one linear scan here and toss out the duplicates.
1131 Note that we are not concerned here about recovering the space that
1132 is potentially freed up, because the strings themselves are allocated
1133 on the storage_obstack, and will get automatically freed when the symbol
1134 table is freed. The caller can free up the unused minimal symbols at
1135 the end of the compacted region if their allocation strategy allows it.
1137 Also note we only go up to the next to last entry within the loop
1138 and then copy the last entry explicitly after the loop terminates.
1140 Since the different sources of information for each symbol may
1141 have different levels of "completeness", we may have duplicates
1142 that have one entry with type "mst_unknown" and the other with a
1143 known type. So if the one we are leaving alone has type mst_unknown,
1144 overwrite its type with the type from the one we are compacting out. */
1147 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1148 struct objfile *objfile)
1150 struct minimal_symbol *copyfrom;
1151 struct minimal_symbol *copyto;
1155 copyfrom = copyto = msymbol;
1156 while (copyfrom < msymbol + mcount - 1)
1158 if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1159 == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1160 && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1161 && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1162 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1164 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1166 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1171 *copyto++ = *copyfrom++;
1173 *copyto++ = *copyfrom++;
1174 mcount = copyto - msymbol;
1179 /* Build (or rebuild) the minimal symbol hash tables. This is necessary
1180 after compacting or sorting the table since the entries move around
1181 thus causing the internal minimal_symbol pointers to become jumbled. */
1184 build_minimal_symbol_hash_tables (struct objfile *objfile)
1187 struct minimal_symbol *msym;
1189 /* Clear the hash tables. */
1190 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1192 objfile->per_bfd->msymbol_hash[i] = 0;
1193 objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1196 /* Now, (re)insert the actual entries. */
1197 for ((i = objfile->per_bfd->minimal_symbol_count,
1198 msym = objfile->per_bfd->msymbols);
1202 msym->hash_next = 0;
1203 add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1205 msym->demangled_hash_next = 0;
1206 if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1207 add_minsym_to_demangled_hash_table (msym,
1208 objfile->per_bfd->msymbol_demangled_hash);
1212 /* Add the minimal symbols in the existing bunches to the objfile's official
1213 minimal symbol table. In most cases there is no minimal symbol table yet
1214 for this objfile, and the existing bunches are used to create one. Once
1215 in a while (for shared libraries for example), we add symbols (e.g. common
1216 symbols) to an existing objfile.
1218 Because of the way minimal symbols are collected, we generally have no way
1219 of knowing what source language applies to any particular minimal symbol.
1220 Specifically, we have no way of knowing if the minimal symbol comes from a
1221 C++ compilation unit or not. So for the sake of supporting cached
1222 demangled C++ names, we have no choice but to try and demangle each new one
1223 that comes in. If the demangling succeeds, then we assume it is a C++
1224 symbol and set the symbol's language and demangled name fields
1225 appropriately. Note that in order to avoid unnecessary demanglings, and
1226 allocating obstack space that subsequently can't be freed for the demangled
1227 names, we mark all newly added symbols with language_auto. After
1228 compaction of the minimal symbols, we go back and scan the entire minimal
1229 symbol table looking for these new symbols. For each new symbol we attempt
1230 to demangle it, and if successful, record it as a language_cplus symbol
1231 and cache the demangled form on the symbol obstack. Symbols which don't
1232 demangle are marked as language_unknown symbols, which inhibits future
1233 attempts to demangle them if we later add more minimal symbols. */
1236 minimal_symbol_reader::install ()
1240 struct msym_bunch *bunch;
1241 struct minimal_symbol *msymbols;
1244 if (m_objfile->per_bfd->minsyms_read)
1249 if (symtab_create_debug)
1251 fprintf_unfiltered (gdb_stdlog,
1252 "Installing %d minimal symbols of objfile %s.\n",
1253 msym_count, objfile_name (m_objfile));
1256 /* Allocate enough space in the obstack, into which we will gather the
1257 bunches of new and existing minimal symbols, sort them, and then
1258 compact out the duplicate entries. Once we have a final table,
1259 we will give back the excess space. */
1261 alloc_count = msym_count + m_objfile->per_bfd->minimal_symbol_count + 1;
1262 obstack_blank (&m_objfile->per_bfd->storage_obstack,
1263 alloc_count * sizeof (struct minimal_symbol));
1264 msymbols = (struct minimal_symbol *)
1265 obstack_base (&m_objfile->per_bfd->storage_obstack);
1267 /* Copy in the existing minimal symbols, if there are any. */
1269 if (m_objfile->per_bfd->minimal_symbol_count)
1270 memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols,
1271 m_objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol));
1273 /* Walk through the list of minimal symbol bunches, adding each symbol
1274 to the new contiguous array of symbols. Note that we start with the
1275 current, possibly partially filled bunch (thus we use the current
1276 msym_bunch_index for the first bunch we copy over), and thereafter
1277 each bunch is full. */
1279 mcount = m_objfile->per_bfd->minimal_symbol_count;
1281 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1283 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1284 msymbols[mcount] = bunch->contents[bindex];
1285 msym_bunch_index = BUNCH_SIZE;
1288 /* Sort the minimal symbols by address. */
1290 qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1291 compare_minimal_symbols);
1293 /* Compact out any duplicates, and free up whatever space we are
1296 mcount = compact_minimal_symbols (msymbols, mcount, m_objfile);
1298 obstack_blank_fast (&m_objfile->per_bfd->storage_obstack,
1299 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1300 msymbols = (struct minimal_symbol *)
1301 obstack_finish (&m_objfile->per_bfd->storage_obstack);
1303 /* We also terminate the minimal symbol table with a "null symbol",
1304 which is *not* included in the size of the table. This makes it
1305 easier to find the end of the table when we are handed a pointer
1306 to some symbol in the middle of it. Zero out the fields in the
1307 "null symbol" allocated at the end of the array. Note that the
1308 symbol count does *not* include this null symbol, which is why it
1309 is indexed by mcount and not mcount-1. */
1311 memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1313 /* Attach the minimal symbol table to the specified objfile.
1314 The strings themselves are also located in the storage_obstack
1317 m_objfile->per_bfd->minimal_symbol_count = mcount;
1318 m_objfile->per_bfd->msymbols = msymbols;
1320 /* Now build the hash tables; we can't do this incrementally
1321 at an earlier point since we weren't finished with the obstack
1322 yet. (And if the msymbol obstack gets moved, all the internal
1323 pointers to other msymbols need to be adjusted.) */
1324 build_minimal_symbol_hash_tables (m_objfile);
1328 /* See minsyms.h. */
1331 terminate_minimal_symbol_table (struct objfile *objfile)
1333 if (! objfile->per_bfd->msymbols)
1334 objfile->per_bfd->msymbols
1335 = ((struct minimal_symbol *)
1336 obstack_alloc (&objfile->per_bfd->storage_obstack,
1337 sizeof (struct minimal_symbol)));
1340 struct minimal_symbol *m
1341 = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1343 memset (m, 0, sizeof (*m));
1344 /* Don't rely on these enumeration values being 0's. */
1345 MSYMBOL_TYPE (m) = mst_unknown;
1346 MSYMBOL_SET_LANGUAGE (m, language_unknown,
1347 &objfile->per_bfd->storage_obstack);
1351 /* Check if PC is in a shared library trampoline code stub.
1352 Return minimal symbol for the trampoline entry or NULL if PC is not
1353 in a trampoline code stub. */
1355 static struct minimal_symbol *
1356 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1358 struct obj_section *section = find_pc_section (pc);
1359 struct bound_minimal_symbol msymbol;
1361 if (section == NULL)
1363 msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1365 if (msymbol.minsym != NULL
1366 && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1367 return msymbol.minsym;
1371 /* If PC is in a shared library trampoline code stub, return the
1372 address of the `real' function belonging to the stub.
1373 Return 0 if PC is not in a trampoline code stub or if the real
1374 function is not found in the minimal symbol table.
1376 We may fail to find the right function if a function with the
1377 same name is defined in more than one shared library, but this
1378 is considered bad programming style. We could return 0 if we find
1379 a duplicate function in case this matters someday. */
1382 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1384 struct objfile *objfile;
1385 struct minimal_symbol *msymbol;
1386 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1388 if (tsymbol != NULL)
1390 ALL_MSYMBOLS (objfile, msymbol)
1392 if ((MSYMBOL_TYPE (msymbol) == mst_text
1393 || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1394 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1395 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1396 return MSYMBOL_VALUE_ADDRESS (objfile, msymbol);
1398 /* Also handle minimal symbols pointing to function descriptors. */
1399 if (MSYMBOL_TYPE (msymbol) == mst_data
1400 && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1401 MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1405 func = gdbarch_convert_from_func_ptr_addr
1406 (get_objfile_arch (objfile),
1407 MSYMBOL_VALUE_ADDRESS (objfile, msymbol),
1410 /* Ignore data symbols that are not function descriptors. */
1411 if (func != MSYMBOL_VALUE_ADDRESS (objfile, msymbol))
1419 /* See minsyms.h. */
1422 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1426 struct obj_section *obj_section;
1428 struct minimal_symbol *msymbol;
1430 gdb_assert (minsym.minsym != NULL);
1432 /* If the minimal symbol has a size, use it. Otherwise use the
1433 lesser of the next minimal symbol in the same section, or the end
1434 of the section, as the end of the function. */
1436 if (MSYMBOL_SIZE (minsym.minsym) != 0)
1437 return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1439 /* Step over other symbols at this same address, and symbols in
1440 other sections, to find the next symbol in this section with a
1441 different address. */
1443 msymbol = minsym.minsym;
1444 section = MSYMBOL_SECTION (msymbol);
1445 for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1447 if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1448 != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1449 && MSYMBOL_SECTION (msymbol + i) == section)
1453 obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1454 if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1455 && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1456 < obj_section_endaddr (obj_section)))
1457 result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
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);