1 /* Read ELF (Executable and Linking Format) object files for GDB.
3 Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
5 Free Software Foundation, Inc.
7 Written by Fred Fish at Cygnus Support.
9 This file is part of GDB.
11 This program is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 3 of the License, or
14 (at your option) any later version.
16 This program is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
21 You should have received a copy of the GNU General Public License
22 along with this program. If not, see <http://www.gnu.org/licenses/>. */
26 #include "gdb_string.h"
28 #include "elf/common.h"
29 #include "elf/internal.h"
35 #include "stabsread.h"
36 #include "gdb-stabs.h"
37 #include "complaints.h"
41 extern void _initialize_elfread (void);
43 /* Forward declaration. */
44 static const struct sym_fns elf_sym_fns_gdb_index
;
46 /* The struct elfinfo is available only during ELF symbol table and
47 psymtab reading. It is destroyed at the completion of psymtab-reading.
48 It's local to elf_symfile_read. */
52 asection
*stabsect
; /* Section pointer for .stab section */
53 asection
*stabindexsect
; /* Section pointer for .stab.index section */
54 asection
*mdebugsect
; /* Section pointer for .mdebug section */
57 static void free_elfinfo (void *);
59 /* Locate the segments in ABFD. */
61 static struct symfile_segment_data
*
62 elf_symfile_segments (bfd
*abfd
)
64 Elf_Internal_Phdr
*phdrs
, **segments
;
66 int num_phdrs
, num_segments
, num_sections
, i
;
68 struct symfile_segment_data
*data
;
70 phdrs_size
= bfd_get_elf_phdr_upper_bound (abfd
);
74 phdrs
= alloca (phdrs_size
);
75 num_phdrs
= bfd_get_elf_phdrs (abfd
, phdrs
);
80 segments
= alloca (sizeof (Elf_Internal_Phdr
*) * num_phdrs
);
81 for (i
= 0; i
< num_phdrs
; i
++)
82 if (phdrs
[i
].p_type
== PT_LOAD
)
83 segments
[num_segments
++] = &phdrs
[i
];
85 if (num_segments
== 0)
88 data
= XZALLOC (struct symfile_segment_data
);
89 data
->num_segments
= num_segments
;
90 data
->segment_bases
= XCALLOC (num_segments
, CORE_ADDR
);
91 data
->segment_sizes
= XCALLOC (num_segments
, CORE_ADDR
);
93 for (i
= 0; i
< num_segments
; i
++)
95 data
->segment_bases
[i
] = segments
[i
]->p_vaddr
;
96 data
->segment_sizes
[i
] = segments
[i
]->p_memsz
;
99 num_sections
= bfd_count_sections (abfd
);
100 data
->segment_info
= XCALLOC (num_sections
, int);
102 for (i
= 0, sect
= abfd
->sections
; sect
!= NULL
; i
++, sect
= sect
->next
)
107 if ((bfd_get_section_flags (abfd
, sect
) & SEC_ALLOC
) == 0)
110 vma
= bfd_get_section_vma (abfd
, sect
);
112 for (j
= 0; j
< num_segments
; j
++)
113 if (segments
[j
]->p_memsz
> 0
114 && vma
>= segments
[j
]->p_vaddr
115 && (vma
- segments
[j
]->p_vaddr
) < segments
[j
]->p_memsz
)
117 data
->segment_info
[i
] = j
+ 1;
121 /* We should have found a segment for every non-empty section.
122 If we haven't, we will not relocate this section by any
123 offsets we apply to the segments. As an exception, do not
124 warn about SHT_NOBITS sections; in normal ELF execution
125 environments, SHT_NOBITS means zero-initialized and belongs
126 in a segment, but in no-OS environments some tools (e.g. ARM
127 RealView) use SHT_NOBITS for uninitialized data. Since it is
128 uninitialized, it doesn't need a program header. Such
129 binaries are not relocatable. */
130 if (bfd_get_section_size (sect
) > 0 && j
== num_segments
131 && (bfd_get_section_flags (abfd
, sect
) & SEC_LOAD
) != 0)
132 warning (_("Loadable segment \"%s\" outside of ELF segments"),
133 bfd_section_name (abfd
, sect
));
139 /* We are called once per section from elf_symfile_read. We
140 need to examine each section we are passed, check to see
141 if it is something we are interested in processing, and
142 if so, stash away some access information for the section.
144 For now we recognize the dwarf debug information sections and
145 line number sections from matching their section names. The
146 ELF definition is no real help here since it has no direct
147 knowledge of DWARF (by design, so any debugging format can be
150 We also recognize the ".stab" sections used by the Sun compilers
151 released with Solaris 2.
153 FIXME: The section names should not be hardwired strings (what
154 should they be? I don't think most object file formats have enough
155 section flags to specify what kind of debug section it is.
159 elf_locate_sections (bfd
*ignore_abfd
, asection
*sectp
, void *eip
)
163 ei
= (struct elfinfo
*) eip
;
164 if (strcmp (sectp
->name
, ".stab") == 0)
166 ei
->stabsect
= sectp
;
168 else if (strcmp (sectp
->name
, ".stab.index") == 0)
170 ei
->stabindexsect
= sectp
;
172 else if (strcmp (sectp
->name
, ".mdebug") == 0)
174 ei
->mdebugsect
= sectp
;
178 static struct minimal_symbol
*
179 record_minimal_symbol (const char *name
, int name_len
, int copy_name
,
181 enum minimal_symbol_type ms_type
,
182 asection
*bfd_section
, struct objfile
*objfile
)
184 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
186 if (ms_type
== mst_text
|| ms_type
== mst_file_text
)
187 address
= gdbarch_smash_text_address (gdbarch
, address
);
189 return prim_record_minimal_symbol_full (name
, name_len
, copy_name
, address
,
190 ms_type
, bfd_section
->index
,
191 bfd_section
, objfile
);
198 elf_symtab_read -- read the symbol table of an ELF file
202 void elf_symtab_read (struct objfile *objfile, int type,
203 long number_of_symbols, asymbol **symbol_table)
207 Given an objfile, a symbol table, and a flag indicating whether the
208 symbol table contains regular, dynamic, or synthetic symbols, add all
209 the global function and data symbols to the minimal symbol table.
211 In stabs-in-ELF, as implemented by Sun, there are some local symbols
212 defined in the ELF symbol table, which can be used to locate
213 the beginnings of sections from each ".o" file that was linked to
214 form the executable objfile. We gather any such info and record it
215 in data structures hung off the objfile's private data.
221 #define ST_SYNTHETIC 2
224 elf_symtab_read (struct objfile
*objfile
, int type
,
225 long number_of_symbols
, asymbol
**symbol_table
,
228 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
233 enum minimal_symbol_type ms_type
;
234 /* If sectinfo is nonNULL, it contains section info that should end up
235 filed in the objfile. */
236 struct stab_section_info
*sectinfo
= NULL
;
237 /* If filesym is nonzero, it points to a file symbol, but we haven't
238 seen any section info for it yet. */
239 asymbol
*filesym
= 0;
240 /* Name of filesym. This is either a constant string or is saved on
241 the objfile's obstack. */
242 char *filesymname
= "";
243 struct dbx_symfile_info
*dbx
= objfile
->deprecated_sym_stab_info
;
244 int stripped
= (bfd_get_symcount (objfile
->obfd
) == 0);
246 for (i
= 0; i
< number_of_symbols
; i
++)
248 sym
= symbol_table
[i
];
249 if (sym
->name
== NULL
|| *sym
->name
== '\0')
251 /* Skip names that don't exist (shouldn't happen), or names
252 that are null strings (may happen). */
256 /* Skip "special" symbols, e.g. ARM mapping symbols. These are
257 symbols which do not correspond to objects in the symbol table,
258 but have some other target-specific meaning. */
259 if (bfd_is_target_special_symbol (objfile
->obfd
, sym
))
261 if (gdbarch_record_special_symbol_p (gdbarch
))
262 gdbarch_record_special_symbol (gdbarch
, objfile
, sym
);
266 offset
= ANOFFSET (objfile
->section_offsets
, sym
->section
->index
);
267 if (type
== ST_DYNAMIC
268 && sym
->section
== &bfd_und_section
269 && (sym
->flags
& BSF_FUNCTION
))
271 struct minimal_symbol
*msym
;
272 bfd
*abfd
= objfile
->obfd
;
275 /* Symbol is a reference to a function defined in
277 If its value is non zero then it is usually the address
278 of the corresponding entry in the procedure linkage table,
279 plus the desired section offset.
280 If its value is zero then the dynamic linker has to resolve
281 the symbol. We are unable to find any meaningful address
282 for this symbol in the executable file, so we skip it. */
283 symaddr
= sym
->value
;
287 /* sym->section is the undefined section. However, we want to
288 record the section where the PLT stub resides with the
289 minimal symbol. Search the section table for the one that
290 covers the stub's address. */
291 for (sect
= abfd
->sections
; sect
!= NULL
; sect
= sect
->next
)
293 if ((bfd_get_section_flags (abfd
, sect
) & SEC_ALLOC
) == 0)
296 if (symaddr
>= bfd_get_section_vma (abfd
, sect
)
297 && symaddr
< bfd_get_section_vma (abfd
, sect
)
298 + bfd_get_section_size (sect
))
304 symaddr
+= ANOFFSET (objfile
->section_offsets
, sect
->index
);
306 msym
= record_minimal_symbol
307 (sym
->name
, strlen (sym
->name
), copy_names
,
308 symaddr
, mst_solib_trampoline
, sect
, objfile
);
310 msym
->filename
= filesymname
;
314 /* If it is a nonstripped executable, do not enter dynamic
315 symbols, as the dynamic symbol table is usually a subset
316 of the main symbol table. */
317 if (type
== ST_DYNAMIC
&& !stripped
)
319 if (sym
->flags
& BSF_FILE
)
321 /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
322 Chain any old one onto the objfile; remember new sym. */
323 if (sectinfo
!= NULL
)
325 sectinfo
->next
= dbx
->stab_section_info
;
326 dbx
->stab_section_info
= sectinfo
;
331 obsavestring ((char *) filesym
->name
, strlen (filesym
->name
),
332 &objfile
->objfile_obstack
);
334 else if (sym
->flags
& BSF_SECTION_SYM
)
336 else if (sym
->flags
& (BSF_GLOBAL
| BSF_LOCAL
| BSF_WEAK
))
338 struct minimal_symbol
*msym
;
340 /* Select global/local/weak symbols. Note that bfd puts abs
341 symbols in their own section, so all symbols we are
342 interested in will have a section. */
343 /* Bfd symbols are section relative. */
344 symaddr
= sym
->value
+ sym
->section
->vma
;
345 /* Relocate all non-absolute and non-TLS symbols by the
347 if (sym
->section
!= &bfd_abs_section
348 && !(sym
->section
->flags
& SEC_THREAD_LOCAL
))
352 /* For non-absolute symbols, use the type of the section
353 they are relative to, to intuit text/data. Bfd provides
354 no way of figuring this out for absolute symbols. */
355 if (sym
->section
== &bfd_abs_section
)
357 /* This is a hack to get the minimal symbol type
358 right for Irix 5, which has absolute addresses
359 with special section indices for dynamic symbols.
361 NOTE: uweigand-20071112: Synthetic symbols do not
362 have an ELF-private part, so do not touch those. */
363 unsigned int shndx
= type
== ST_SYNTHETIC
? 0 :
364 ((elf_symbol_type
*) sym
)->internal_elf_sym
.st_shndx
;
374 case SHN_MIPS_ACOMMON
:
381 /* If it is an Irix dynamic symbol, skip section name
382 symbols, relocate all others by section offset. */
383 if (ms_type
!= mst_abs
)
385 if (sym
->name
[0] == '.')
390 else if (sym
->section
->flags
& SEC_CODE
)
392 if (sym
->flags
& (BSF_GLOBAL
| BSF_WEAK
))
396 else if ((sym
->name
[0] == '.' && sym
->name
[1] == 'L')
397 || ((sym
->flags
& BSF_LOCAL
)
398 && sym
->name
[0] == '$'
399 && sym
->name
[1] == 'L'))
400 /* Looks like a compiler-generated label. Skip
401 it. The assembler should be skipping these (to
402 keep executables small), but apparently with
403 gcc on the (deleted) delta m88k SVR4, it loses.
404 So to have us check too should be harmless (but
405 I encourage people to fix this in the assembler
406 instead of adding checks here). */
410 ms_type
= mst_file_text
;
413 else if (sym
->section
->flags
& SEC_ALLOC
)
415 if (sym
->flags
& (BSF_GLOBAL
| BSF_WEAK
))
417 if (sym
->section
->flags
& SEC_LOAD
)
426 else if (sym
->flags
& BSF_LOCAL
)
428 /* Named Local variable in a Data section.
429 Check its name for stabs-in-elf. */
430 int special_local_sect
;
432 if (strcmp ("Bbss.bss", sym
->name
) == 0)
433 special_local_sect
= SECT_OFF_BSS (objfile
);
434 else if (strcmp ("Ddata.data", sym
->name
) == 0)
435 special_local_sect
= SECT_OFF_DATA (objfile
);
436 else if (strcmp ("Drodata.rodata", sym
->name
) == 0)
437 special_local_sect
= SECT_OFF_RODATA (objfile
);
439 special_local_sect
= -1;
440 if (special_local_sect
>= 0)
442 /* Found a special local symbol. Allocate a
443 sectinfo, if needed, and fill it in. */
444 if (sectinfo
== NULL
)
449 max_index
= SECT_OFF_BSS (objfile
);
450 if (objfile
->sect_index_data
> max_index
)
451 max_index
= objfile
->sect_index_data
;
452 if (objfile
->sect_index_rodata
> max_index
)
453 max_index
= objfile
->sect_index_rodata
;
455 /* max_index is the largest index we'll
456 use into this array, so we must
457 allocate max_index+1 elements for it.
458 However, 'struct stab_section_info'
459 already includes one element, so we
460 need to allocate max_index aadditional
462 size
= (sizeof (struct stab_section_info
)
463 + (sizeof (CORE_ADDR
) * max_index
));
464 sectinfo
= (struct stab_section_info
*)
466 memset (sectinfo
, 0, size
);
467 sectinfo
->num_sections
= max_index
;
470 complaint (&symfile_complaints
,
471 _("elf/stab section information %s "
472 "without a preceding file symbol"),
478 (char *) filesym
->name
;
481 if (sectinfo
->sections
[special_local_sect
] != 0)
482 complaint (&symfile_complaints
,
483 _("duplicated elf/stab section "
484 "information for %s"),
486 /* BFD symbols are section relative. */
487 symaddr
= sym
->value
+ sym
->section
->vma
;
488 /* Relocate non-absolute symbols by the
490 if (sym
->section
!= &bfd_abs_section
)
492 sectinfo
->sections
[special_local_sect
] = symaddr
;
493 /* The special local symbols don't go in the
494 minimal symbol table, so ignore this one. */
497 /* Not a special stabs-in-elf symbol, do regular
498 symbol processing. */
499 if (sym
->section
->flags
& SEC_LOAD
)
501 ms_type
= mst_file_data
;
505 ms_type
= mst_file_bss
;
510 ms_type
= mst_unknown
;
515 /* FIXME: Solaris2 shared libraries include lots of
516 odd "absolute" and "undefined" symbols, that play
517 hob with actions like finding what function the PC
518 is in. Ignore them if they aren't text, data, or bss. */
519 /* ms_type = mst_unknown; */
520 continue; /* Skip this symbol. */
522 msym
= record_minimal_symbol
523 (sym
->name
, strlen (sym
->name
), copy_names
, symaddr
,
524 ms_type
, sym
->section
, objfile
);
528 /* Pass symbol size field in via BFD. FIXME!!! */
529 elf_symbol_type
*elf_sym
;
531 /* NOTE: uweigand-20071112: A synthetic symbol does not have an
532 ELF-private part. However, in some cases (e.g. synthetic
533 'dot' symbols on ppc64) the udata.p entry is set to point back
534 to the original ELF symbol it was derived from. Get the size
536 if (type
!= ST_SYNTHETIC
)
537 elf_sym
= (elf_symbol_type
*) sym
;
539 elf_sym
= (elf_symbol_type
*) sym
->udata
.p
;
542 MSYMBOL_SIZE(msym
) = elf_sym
->internal_elf_sym
.st_size
;
544 msym
->filename
= filesymname
;
545 gdbarch_elf_make_msymbol_special (gdbarch
, sym
, msym
);
548 /* For @plt symbols, also record a trampoline to the
549 destination symbol. The @plt symbol will be used in
550 disassembly, and the trampoline will be used when we are
551 trying to find the target. */
552 if (msym
&& ms_type
== mst_text
&& type
== ST_SYNTHETIC
)
554 int len
= strlen (sym
->name
);
556 if (len
> 4 && strcmp (sym
->name
+ len
- 4, "@plt") == 0)
558 struct minimal_symbol
*mtramp
;
560 mtramp
= record_minimal_symbol (sym
->name
, len
- 4, 1,
562 mst_solib_trampoline
,
563 sym
->section
, objfile
);
566 MSYMBOL_SIZE (mtramp
) = MSYMBOL_SIZE (msym
);
567 mtramp
->filename
= filesymname
;
568 gdbarch_elf_make_msymbol_special (gdbarch
, sym
, mtramp
);
582 /* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
584 static struct build_id
*
585 build_id_bfd_get (bfd
*abfd
)
587 struct build_id
*retval
;
589 if (!bfd_check_format (abfd
, bfd_object
)
590 || bfd_get_flavour (abfd
) != bfd_target_elf_flavour
591 || elf_tdata (abfd
)->build_id
== NULL
)
594 retval
= xmalloc (sizeof *retval
- 1 + elf_tdata (abfd
)->build_id_size
);
595 retval
->size
= elf_tdata (abfd
)->build_id_size
;
596 memcpy (retval
->data
, elf_tdata (abfd
)->build_id
, retval
->size
);
601 /* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */
604 build_id_verify (const char *filename
, struct build_id
*check
)
607 struct build_id
*found
= NULL
;
610 /* We expect to be silent on the non-existing files. */
611 abfd
= bfd_open_maybe_remote (filename
);
615 found
= build_id_bfd_get (abfd
);
618 warning (_("File \"%s\" has no build-id, file skipped"), filename
);
619 else if (found
->size
!= check
->size
620 || memcmp (found
->data
, check
->data
, found
->size
) != 0)
621 warning (_("File \"%s\" has a different build-id, file skipped"),
626 gdb_bfd_close_or_warn (abfd
);
634 build_id_to_debug_filename (struct build_id
*build_id
)
636 char *link
, *debugdir
, *retval
= NULL
;
638 /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
639 link
= alloca (strlen (debug_file_directory
) + (sizeof "/.build-id/" - 1) + 1
640 + 2 * build_id
->size
+ (sizeof ".debug" - 1) + 1);
642 /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
643 cause "/.build-id/..." lookups. */
645 debugdir
= debug_file_directory
;
648 char *s
, *debugdir_end
;
649 gdb_byte
*data
= build_id
->data
;
650 size_t size
= build_id
->size
;
652 while (*debugdir
== DIRNAME_SEPARATOR
)
655 debugdir_end
= strchr (debugdir
, DIRNAME_SEPARATOR
);
656 if (debugdir_end
== NULL
)
657 debugdir_end
= &debugdir
[strlen (debugdir
)];
659 memcpy (link
, debugdir
, debugdir_end
- debugdir
);
660 s
= &link
[debugdir_end
- debugdir
];
661 s
+= sprintf (s
, "/.build-id/");
665 s
+= sprintf (s
, "%02x", (unsigned) *data
++);
670 s
+= sprintf (s
, "%02x", (unsigned) *data
++);
671 strcpy (s
, ".debug");
673 /* lrealpath() is expensive even for the usually non-existent files. */
674 if (access (link
, F_OK
) == 0)
675 retval
= lrealpath (link
);
677 if (retval
!= NULL
&& !build_id_verify (retval
, build_id
))
686 debugdir
= debugdir_end
;
688 while (*debugdir
!= 0);
694 find_separate_debug_file_by_buildid (struct objfile
*objfile
)
696 struct build_id
*build_id
;
698 build_id
= build_id_bfd_get (objfile
->obfd
);
699 if (build_id
!= NULL
)
703 build_id_name
= build_id_to_debug_filename (build_id
);
705 /* Prevent looping on a stripped .debug file. */
706 if (build_id_name
!= NULL
&& strcmp (build_id_name
, objfile
->name
) == 0)
708 warning (_("\"%s\": separate debug info file has no debug info"),
710 xfree (build_id_name
);
712 else if (build_id_name
!= NULL
)
713 return build_id_name
;
718 /* Scan and build partial symbols for a symbol file.
719 We have been initialized by a call to elf_symfile_init, which
720 currently does nothing.
722 SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
723 in each section. We simplify it down to a single offset for all
726 This function only does the minimum work necessary for letting the
727 user "name" things symbolically; it does not read the entire symtab.
728 Instead, it reads the external and static symbols and puts them in partial
729 symbol tables. When more extensive information is requested of a
730 file, the corresponding partial symbol table is mutated into a full
731 fledged symbol table by going back and reading the symbols
734 We look for sections with specific names, to tell us what debug
735 format to look for: FIXME!!!
737 elfstab_build_psymtabs() handles STABS symbols;
738 mdebug_build_psymtabs() handles ECOFF debugging information.
740 Note that ELF files have a "minimal" symbol table, which looks a lot
741 like a COFF symbol table, but has only the minimal information necessary
742 for linking. We process this also, and use the information to
743 build gdb's minimal symbol table. This gives us some minimal debugging
744 capability even for files compiled without -g. */
747 elf_symfile_read (struct objfile
*objfile
, int symfile_flags
)
749 bfd
*abfd
= objfile
->obfd
;
751 struct cleanup
*back_to
;
752 long symcount
= 0, dynsymcount
= 0, synthcount
, storage_needed
;
753 asymbol
**symbol_table
= NULL
, **dyn_symbol_table
= NULL
;
756 init_minimal_symbol_collection ();
757 back_to
= make_cleanup_discard_minimal_symbols ();
759 memset ((char *) &ei
, 0, sizeof (ei
));
761 /* Allocate struct to keep track of the symfile. */
762 objfile
->deprecated_sym_stab_info
= (struct dbx_symfile_info
*)
763 xmalloc (sizeof (struct dbx_symfile_info
));
764 memset ((char *) objfile
->deprecated_sym_stab_info
,
765 0, sizeof (struct dbx_symfile_info
));
766 make_cleanup (free_elfinfo
, (void *) objfile
);
768 /* Process the normal ELF symbol table first. This may write some
769 chain of info into the dbx_symfile_info in
770 objfile->deprecated_sym_stab_info, which can later be used by
771 elfstab_offset_sections. */
773 storage_needed
= bfd_get_symtab_upper_bound (objfile
->obfd
);
774 if (storage_needed
< 0)
775 error (_("Can't read symbols from %s: %s"),
776 bfd_get_filename (objfile
->obfd
),
777 bfd_errmsg (bfd_get_error ()));
779 if (storage_needed
> 0)
781 symbol_table
= (asymbol
**) xmalloc (storage_needed
);
782 make_cleanup (xfree
, symbol_table
);
783 symcount
= bfd_canonicalize_symtab (objfile
->obfd
, symbol_table
);
786 error (_("Can't read symbols from %s: %s"),
787 bfd_get_filename (objfile
->obfd
),
788 bfd_errmsg (bfd_get_error ()));
790 elf_symtab_read (objfile
, ST_REGULAR
, symcount
, symbol_table
, 0);
793 /* Add the dynamic symbols. */
795 storage_needed
= bfd_get_dynamic_symtab_upper_bound (objfile
->obfd
);
797 if (storage_needed
> 0)
799 /* Memory gets permanently referenced from ABFD after
800 bfd_get_synthetic_symtab so it must not get freed before ABFD gets.
801 It happens only in the case when elf_slurp_reloc_table sees
802 asection->relocation NULL. Determining which section is asection is
803 done by _bfd_elf_get_synthetic_symtab which is all a bfd
804 implementation detail, though. */
806 dyn_symbol_table
= bfd_alloc (abfd
, storage_needed
);
807 dynsymcount
= bfd_canonicalize_dynamic_symtab (objfile
->obfd
,
811 error (_("Can't read symbols from %s: %s"),
812 bfd_get_filename (objfile
->obfd
),
813 bfd_errmsg (bfd_get_error ()));
815 elf_symtab_read (objfile
, ST_DYNAMIC
, dynsymcount
, dyn_symbol_table
, 0);
818 /* Add synthetic symbols - for instance, names for any PLT entries. */
820 synthcount
= bfd_get_synthetic_symtab (abfd
, symcount
, symbol_table
,
821 dynsymcount
, dyn_symbol_table
,
825 asymbol
**synth_symbol_table
;
828 make_cleanup (xfree
, synthsyms
);
829 synth_symbol_table
= xmalloc (sizeof (asymbol
*) * synthcount
);
830 for (i
= 0; i
< synthcount
; i
++)
831 synth_symbol_table
[i
] = synthsyms
+ i
;
832 make_cleanup (xfree
, synth_symbol_table
);
833 elf_symtab_read (objfile
, ST_SYNTHETIC
, synthcount
,
834 synth_symbol_table
, 1);
837 /* Install any minimal symbols that have been collected as the current
838 minimal symbols for this objfile. The debug readers below this point
839 should not generate new minimal symbols; if they do it's their
840 responsibility to install them. "mdebug" appears to be the only one
841 which will do this. */
843 install_minimal_symbols (objfile
);
844 do_cleanups (back_to
);
846 /* Now process debugging information, which is contained in
847 special ELF sections. */
849 /* We first have to find them... */
850 bfd_map_over_sections (abfd
, elf_locate_sections
, (void *) & ei
);
852 /* ELF debugging information is inserted into the psymtab in the
853 order of least informative first - most informative last. Since
854 the psymtab table is searched `most recent insertion first' this
855 increases the probability that more detailed debug information
856 for a section is found.
858 For instance, an object file might contain both .mdebug (XCOFF)
859 and .debug_info (DWARF2) sections then .mdebug is inserted first
860 (searched last) and DWARF2 is inserted last (searched first). If
861 we don't do this then the XCOFF info is found first - for code in
862 an included file XCOFF info is useless. */
866 const struct ecoff_debug_swap
*swap
;
868 /* .mdebug section, presumably holding ECOFF debugging
870 swap
= get_elf_backend_data (abfd
)->elf_backend_ecoff_debug_swap
;
872 elfmdebug_build_psymtabs (objfile
, swap
, ei
.mdebugsect
);
878 /* Stab sections have an associated string table that looks like
879 a separate section. */
880 str_sect
= bfd_get_section_by_name (abfd
, ".stabstr");
882 /* FIXME should probably warn about a stab section without a stabstr. */
884 elfstab_build_psymtabs (objfile
,
887 bfd_section_size (abfd
, str_sect
));
890 if (dwarf2_has_info (objfile
) && dwarf2_initialize_objfile (objfile
))
891 objfile
->sf
= &elf_sym_fns_gdb_index
;
893 /* If the file has its own symbol tables it has no separate debug
894 info. `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to
895 SYMTABS/PSYMTABS. `.gnu_debuglink' may no longer be present with
896 `.note.gnu.build-id'. */
897 if (!objfile_has_partial_symbols (objfile
))
901 debugfile
= find_separate_debug_file_by_buildid (objfile
);
903 if (debugfile
== NULL
)
904 debugfile
= find_separate_debug_file_by_debuglink (objfile
);
908 bfd
*abfd
= symfile_bfd_open (debugfile
);
910 symbol_file_add_separate (abfd
, symfile_flags
, objfile
);
916 /* This cleans up the objfile's deprecated_sym_stab_info pointer, and
917 the chain of stab_section_info's, that might be dangling from
921 free_elfinfo (void *objp
)
923 struct objfile
*objfile
= (struct objfile
*) objp
;
924 struct dbx_symfile_info
*dbxinfo
= objfile
->deprecated_sym_stab_info
;
925 struct stab_section_info
*ssi
, *nssi
;
927 ssi
= dbxinfo
->stab_section_info
;
935 dbxinfo
->stab_section_info
= 0; /* Just say No mo info about this. */
939 /* Initialize anything that needs initializing when a completely new symbol
940 file is specified (not just adding some symbols from another file, e.g. a
943 We reinitialize buildsym, since we may be reading stabs from an ELF
947 elf_new_init (struct objfile
*ignore
)
949 stabsread_new_init ();
950 buildsym_new_init ();
953 /* Perform any local cleanups required when we are done with a particular
954 objfile. I.E, we are in the process of discarding all symbol information
955 for an objfile, freeing up all memory held for it, and unlinking the
956 objfile struct from the global list of known objfiles. */
959 elf_symfile_finish (struct objfile
*objfile
)
961 if (objfile
->deprecated_sym_stab_info
!= NULL
)
963 xfree (objfile
->deprecated_sym_stab_info
);
966 dwarf2_free_objfile (objfile
);
969 /* ELF specific initialization routine for reading symbols.
971 It is passed a pointer to a struct sym_fns which contains, among other
972 things, the BFD for the file whose symbols are being read, and a slot for
973 a pointer to "private data" which we can fill with goodies.
975 For now at least, we have nothing in particular to do, so this function is
979 elf_symfile_init (struct objfile
*objfile
)
981 /* ELF objects may be reordered, so set OBJF_REORDERED. If we
982 find this causes a significant slowdown in gdb then we could
983 set it in the debug symbol readers only when necessary. */
984 objfile
->flags
|= OBJF_REORDERED
;
987 /* When handling an ELF file that contains Sun STABS debug info,
988 some of the debug info is relative to the particular chunk of the
989 section that was generated in its individual .o file. E.g.
990 offsets to static variables are relative to the start of the data
991 segment *for that module before linking*. This information is
992 painfully squirreled away in the ELF symbol table as local symbols
993 with wierd names. Go get 'em when needed. */
996 elfstab_offset_sections (struct objfile
*objfile
, struct partial_symtab
*pst
)
998 const char *filename
= pst
->filename
;
999 struct dbx_symfile_info
*dbx
= objfile
->deprecated_sym_stab_info
;
1000 struct stab_section_info
*maybe
= dbx
->stab_section_info
;
1001 struct stab_section_info
*questionable
= 0;
1005 /* The ELF symbol info doesn't include path names, so strip the path
1006 (if any) from the psymtab filename. */
1007 while (0 != (p
= strchr (filename
, '/')))
1010 /* FIXME: This linear search could speed up significantly
1011 if it was chained in the right order to match how we search it,
1012 and if we unchained when we found a match. */
1013 for (; maybe
; maybe
= maybe
->next
)
1015 if (filename
[0] == maybe
->filename
[0]
1016 && strcmp (filename
, maybe
->filename
) == 0)
1018 /* We found a match. But there might be several source files
1019 (from different directories) with the same name. */
1020 if (0 == maybe
->found
)
1022 questionable
= maybe
; /* Might use it later. */
1026 if (maybe
== 0 && questionable
!= 0)
1028 complaint (&symfile_complaints
,
1029 _("elf/stab section information questionable for %s"),
1031 maybe
= questionable
;
1036 /* Found it! Allocate a new psymtab struct, and fill it in. */
1038 pst
->section_offsets
= (struct section_offsets
*)
1039 obstack_alloc (&objfile
->objfile_obstack
,
1040 SIZEOF_N_SECTION_OFFSETS (objfile
->num_sections
));
1041 for (i
= 0; i
< maybe
->num_sections
; i
++)
1042 (pst
->section_offsets
)->offsets
[i
] = maybe
->sections
[i
];
1046 /* We were unable to find any offsets for this file. Complain. */
1047 if (dbx
->stab_section_info
) /* If there *is* any info, */
1048 complaint (&symfile_complaints
,
1049 _("elf/stab section information missing for %s"), filename
);
1052 /* Register that we are able to handle ELF object file formats. */
1054 static const struct sym_fns elf_sym_fns
=
1056 bfd_target_elf_flavour
,
1057 elf_new_init
, /* init anything gbl to entire symtab */
1058 elf_symfile_init
, /* read initial info, setup for sym_read() */
1059 elf_symfile_read
, /* read a symbol file into symtab */
1060 elf_symfile_finish
, /* finished with file, cleanup */
1061 default_symfile_offsets
, /* Translate ext. to int. relocation */
1062 elf_symfile_segments
, /* Get segment information from a file. */
1064 default_symfile_relocate
, /* Relocate a debug section. */
1068 /* The same as elf_sym_fns, but not registered and uses the
1069 DWARF-specific GNU index rather than psymtab. */
1070 static const struct sym_fns elf_sym_fns_gdb_index
=
1072 bfd_target_elf_flavour
,
1073 elf_new_init
, /* init anything gbl to entire symab */
1074 elf_symfile_init
, /* read initial info, setup for sym_red() */
1075 elf_symfile_read
, /* read a symbol file into symtab */
1076 elf_symfile_finish
, /* finished with file, cleanup */
1077 default_symfile_offsets
, /* Translate ext. to int. relocatin */
1078 elf_symfile_segments
, /* Get segment information from a file. */
1080 default_symfile_relocate
, /* Relocate a debug section. */
1081 &dwarf2_gdb_index_functions
1085 _initialize_elfread (void)
1087 add_symtab_fns (&elf_sym_fns
);