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"
40 #include "filenames.h"
42 extern void _initialize_elfread (void);
44 /* Forward declarations. */
45 static const struct sym_fns elf_sym_fns_gdb_index;
46 static const struct sym_fns elf_sym_fns_lazy_psyms;
48 /* The struct elfinfo is available only during ELF symbol table and
49 psymtab reading. It is destroyed at the completion of psymtab-reading.
50 It's local to elf_symfile_read. */
54 asection *stabsect; /* Section pointer for .stab section */
55 asection *stabindexsect; /* Section pointer for .stab.index section */
56 asection *mdebugsect; /* Section pointer for .mdebug section */
59 static void free_elfinfo (void *);
61 /* Locate the segments in ABFD. */
63 static struct symfile_segment_data *
64 elf_symfile_segments (bfd *abfd)
66 Elf_Internal_Phdr *phdrs, **segments;
68 int num_phdrs, num_segments, num_sections, i;
70 struct symfile_segment_data *data;
72 phdrs_size = bfd_get_elf_phdr_upper_bound (abfd);
76 phdrs = alloca (phdrs_size);
77 num_phdrs = bfd_get_elf_phdrs (abfd, phdrs);
82 segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs);
83 for (i = 0; i < num_phdrs; i++)
84 if (phdrs[i].p_type == PT_LOAD)
85 segments[num_segments++] = &phdrs[i];
87 if (num_segments == 0)
90 data = XZALLOC (struct symfile_segment_data);
91 data->num_segments = num_segments;
92 data->segment_bases = XCALLOC (num_segments, CORE_ADDR);
93 data->segment_sizes = XCALLOC (num_segments, CORE_ADDR);
95 for (i = 0; i < num_segments; i++)
97 data->segment_bases[i] = segments[i]->p_vaddr;
98 data->segment_sizes[i] = segments[i]->p_memsz;
101 num_sections = bfd_count_sections (abfd);
102 data->segment_info = XCALLOC (num_sections, int);
104 for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
109 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
112 vma = bfd_get_section_vma (abfd, sect);
114 for (j = 0; j < num_segments; j++)
115 if (segments[j]->p_memsz > 0
116 && vma >= segments[j]->p_vaddr
117 && (vma - segments[j]->p_vaddr) < segments[j]->p_memsz)
119 data->segment_info[i] = j + 1;
123 /* We should have found a segment for every non-empty section.
124 If we haven't, we will not relocate this section by any
125 offsets we apply to the segments. As an exception, do not
126 warn about SHT_NOBITS sections; in normal ELF execution
127 environments, SHT_NOBITS means zero-initialized and belongs
128 in a segment, but in no-OS environments some tools (e.g. ARM
129 RealView) use SHT_NOBITS for uninitialized data. Since it is
130 uninitialized, it doesn't need a program header. Such
131 binaries are not relocatable. */
132 if (bfd_get_section_size (sect) > 0 && j == num_segments
133 && (bfd_get_section_flags (abfd, sect) & SEC_LOAD) != 0)
134 warning (_("Loadable segment \"%s\" outside of ELF segments"),
135 bfd_section_name (abfd, sect));
141 /* We are called once per section from elf_symfile_read. We
142 need to examine each section we are passed, check to see
143 if it is something we are interested in processing, and
144 if so, stash away some access information for the section.
146 For now we recognize the dwarf debug information sections and
147 line number sections from matching their section names. The
148 ELF definition is no real help here since it has no direct
149 knowledge of DWARF (by design, so any debugging format can be
152 We also recognize the ".stab" sections used by the Sun compilers
153 released with Solaris 2.
155 FIXME: The section names should not be hardwired strings (what
156 should they be? I don't think most object file formats have enough
157 section flags to specify what kind of debug section it is.
161 elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip)
165 ei = (struct elfinfo *) eip;
166 if (strcmp (sectp->name, ".stab") == 0)
168 ei->stabsect = sectp;
170 else if (strcmp (sectp->name, ".stab.index") == 0)
172 ei->stabindexsect = sectp;
174 else if (strcmp (sectp->name, ".mdebug") == 0)
176 ei->mdebugsect = sectp;
180 static struct minimal_symbol *
181 record_minimal_symbol (const char *name, int name_len, int copy_name,
183 enum minimal_symbol_type ms_type,
184 asection *bfd_section, struct objfile *objfile)
186 struct gdbarch *gdbarch = get_objfile_arch (objfile);
188 if (ms_type == mst_text || ms_type == mst_file_text
189 || ms_type == mst_text_gnu_ifunc)
190 address = gdbarch_smash_text_address (gdbarch, address);
192 return prim_record_minimal_symbol_full (name, name_len, copy_name, address,
193 ms_type, bfd_section->index,
194 bfd_section, objfile);
201 elf_symtab_read -- read the symbol table of an ELF file
205 void elf_symtab_read (struct objfile *objfile, int type,
206 long number_of_symbols, asymbol **symbol_table)
210 Given an objfile, a symbol table, and a flag indicating whether the
211 symbol table contains regular, dynamic, or synthetic symbols, add all
212 the global function and data symbols to the minimal symbol table.
214 In stabs-in-ELF, as implemented by Sun, there are some local symbols
215 defined in the ELF symbol table, which can be used to locate
216 the beginnings of sections from each ".o" file that was linked to
217 form the executable objfile. We gather any such info and record it
218 in data structures hung off the objfile's private data.
224 #define ST_SYNTHETIC 2
227 elf_symtab_read (struct objfile *objfile, int type,
228 long number_of_symbols, asymbol **symbol_table,
231 struct gdbarch *gdbarch = get_objfile_arch (objfile);
236 enum minimal_symbol_type ms_type;
237 /* If sectinfo is nonNULL, it contains section info that should end up
238 filed in the objfile. */
239 struct stab_section_info *sectinfo = NULL;
240 /* If filesym is nonzero, it points to a file symbol, but we haven't
241 seen any section info for it yet. */
242 asymbol *filesym = 0;
243 /* Name of filesym. This is either a constant string or is saved on
244 the objfile's obstack. */
245 char *filesymname = "";
246 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
247 int stripped = (bfd_get_symcount (objfile->obfd) == 0);
248 struct cleanup *back_to = make_cleanup (null_cleanup, NULL);
250 for (i = 0; i < number_of_symbols; i++)
252 sym = symbol_table[i];
253 if (sym->name == NULL || *sym->name == '\0')
255 /* Skip names that don't exist (shouldn't happen), or names
256 that are null strings (may happen). */
260 /* Skip "special" symbols, e.g. ARM mapping symbols. These are
261 symbols which do not correspond to objects in the symbol table,
262 but have some other target-specific meaning. */
263 if (bfd_is_target_special_symbol (objfile->obfd, sym))
265 if (gdbarch_record_special_symbol_p (gdbarch))
266 gdbarch_record_special_symbol (gdbarch, objfile, sym);
270 offset = ANOFFSET (objfile->section_offsets, sym->section->index);
271 if (type == ST_DYNAMIC
272 && sym->section == &bfd_und_section
273 && (sym->flags & BSF_FUNCTION))
275 struct minimal_symbol *msym;
276 bfd *abfd = objfile->obfd;
279 /* Symbol is a reference to a function defined in
281 If its value is non zero then it is usually the address
282 of the corresponding entry in the procedure linkage table,
283 plus the desired section offset.
284 If its value is zero then the dynamic linker has to resolve
285 the symbol. We are unable to find any meaningful address
286 for this symbol in the executable file, so we skip it. */
287 symaddr = sym->value;
291 /* sym->section is the undefined section. However, we want to
292 record the section where the PLT stub resides with the
293 minimal symbol. Search the section table for the one that
294 covers the stub's address. */
295 for (sect = abfd->sections; sect != NULL; sect = sect->next)
297 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
300 if (symaddr >= bfd_get_section_vma (abfd, sect)
301 && symaddr < bfd_get_section_vma (abfd, sect)
302 + bfd_get_section_size (sect))
308 symaddr += ANOFFSET (objfile->section_offsets, sect->index);
310 msym = record_minimal_symbol
311 (sym->name, strlen (sym->name), copy_names,
312 symaddr, mst_solib_trampoline, sect, objfile);
314 msym->filename = filesymname;
318 /* If it is a nonstripped executable, do not enter dynamic
319 symbols, as the dynamic symbol table is usually a subset
320 of the main symbol table. */
321 if (type == ST_DYNAMIC && !stripped)
323 if (sym->flags & BSF_FILE)
325 /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
326 Chain any old one onto the objfile; remember new sym. */
327 if (sectinfo != NULL)
329 sectinfo->next = dbx->stab_section_info;
330 dbx->stab_section_info = sectinfo;
335 obsavestring ((char *) filesym->name, strlen (filesym->name),
336 &objfile->objfile_obstack);
338 else if (sym->flags & BSF_SECTION_SYM)
340 else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
342 struct minimal_symbol *msym;
344 /* Select global/local/weak symbols. Note that bfd puts abs
345 symbols in their own section, so all symbols we are
346 interested in will have a section. */
347 /* Bfd symbols are section relative. */
348 symaddr = sym->value + sym->section->vma;
349 /* Relocate all non-absolute and non-TLS symbols by the
351 if (sym->section != &bfd_abs_section
352 && !(sym->section->flags & SEC_THREAD_LOCAL))
356 /* For non-absolute symbols, use the type of the section
357 they are relative to, to intuit text/data. Bfd provides
358 no way of figuring this out for absolute symbols. */
359 if (sym->section == &bfd_abs_section)
361 /* This is a hack to get the minimal symbol type
362 right for Irix 5, which has absolute addresses
363 with special section indices for dynamic symbols.
365 NOTE: uweigand-20071112: Synthetic symbols do not
366 have an ELF-private part, so do not touch those. */
367 unsigned int shndx = type == ST_SYNTHETIC ? 0 :
368 ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
378 case SHN_MIPS_ACOMMON:
385 /* If it is an Irix dynamic symbol, skip section name
386 symbols, relocate all others by section offset. */
387 if (ms_type != mst_abs)
389 if (sym->name[0] == '.')
394 else if (sym->section->flags & SEC_CODE)
396 if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
398 if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
399 ms_type = mst_text_gnu_ifunc;
403 else if ((sym->name[0] == '.' && sym->name[1] == 'L')
404 || ((sym->flags & BSF_LOCAL)
405 && sym->name[0] == '$'
406 && sym->name[1] == 'L'))
407 /* Looks like a compiler-generated label. Skip
408 it. The assembler should be skipping these (to
409 keep executables small), but apparently with
410 gcc on the (deleted) delta m88k SVR4, it loses.
411 So to have us check too should be harmless (but
412 I encourage people to fix this in the assembler
413 instead of adding checks here). */
417 ms_type = mst_file_text;
420 else if (sym->section->flags & SEC_ALLOC)
422 if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
424 if (sym->section->flags & SEC_LOAD)
433 else if (sym->flags & BSF_LOCAL)
435 /* Named Local variable in a Data section.
436 Check its name for stabs-in-elf. */
437 int special_local_sect;
439 if (strcmp ("Bbss.bss", sym->name) == 0)
440 special_local_sect = SECT_OFF_BSS (objfile);
441 else if (strcmp ("Ddata.data", sym->name) == 0)
442 special_local_sect = SECT_OFF_DATA (objfile);
443 else if (strcmp ("Drodata.rodata", sym->name) == 0)
444 special_local_sect = SECT_OFF_RODATA (objfile);
446 special_local_sect = -1;
447 if (special_local_sect >= 0)
449 /* Found a special local symbol. Allocate a
450 sectinfo, if needed, and fill it in. */
451 if (sectinfo == NULL)
456 max_index = SECT_OFF_BSS (objfile);
457 if (objfile->sect_index_data > max_index)
458 max_index = objfile->sect_index_data;
459 if (objfile->sect_index_rodata > max_index)
460 max_index = objfile->sect_index_rodata;
462 /* max_index is the largest index we'll
463 use into this array, so we must
464 allocate max_index+1 elements for it.
465 However, 'struct stab_section_info'
466 already includes one element, so we
467 need to allocate max_index aadditional
469 size = (sizeof (struct stab_section_info)
470 + (sizeof (CORE_ADDR) * max_index));
471 sectinfo = (struct stab_section_info *)
473 make_cleanup (xfree, sectinfo);
474 memset (sectinfo, 0, size);
475 sectinfo->num_sections = max_index;
478 complaint (&symfile_complaints,
479 _("elf/stab section information %s "
480 "without a preceding file symbol"),
486 (char *) filesym->name;
489 if (sectinfo->sections[special_local_sect] != 0)
490 complaint (&symfile_complaints,
491 _("duplicated elf/stab section "
492 "information for %s"),
494 /* BFD symbols are section relative. */
495 symaddr = sym->value + sym->section->vma;
496 /* Relocate non-absolute symbols by the
498 if (sym->section != &bfd_abs_section)
500 sectinfo->sections[special_local_sect] = symaddr;
501 /* The special local symbols don't go in the
502 minimal symbol table, so ignore this one. */
505 /* Not a special stabs-in-elf symbol, do regular
506 symbol processing. */
507 if (sym->section->flags & SEC_LOAD)
509 ms_type = mst_file_data;
513 ms_type = mst_file_bss;
518 ms_type = mst_unknown;
523 /* FIXME: Solaris2 shared libraries include lots of
524 odd "absolute" and "undefined" symbols, that play
525 hob with actions like finding what function the PC
526 is in. Ignore them if they aren't text, data, or bss. */
527 /* ms_type = mst_unknown; */
528 continue; /* Skip this symbol. */
530 msym = record_minimal_symbol
531 (sym->name, strlen (sym->name), copy_names, symaddr,
532 ms_type, sym->section, objfile);
536 /* Pass symbol size field in via BFD. FIXME!!! */
537 elf_symbol_type *elf_sym;
539 /* NOTE: uweigand-20071112: A synthetic symbol does not have an
540 ELF-private part. However, in some cases (e.g. synthetic
541 'dot' symbols on ppc64) the udata.p entry is set to point back
542 to the original ELF symbol it was derived from. Get the size
544 if (type != ST_SYNTHETIC)
545 elf_sym = (elf_symbol_type *) sym;
547 elf_sym = (elf_symbol_type *) sym->udata.p;
550 MSYMBOL_SIZE(msym) = elf_sym->internal_elf_sym.st_size;
552 msym->filename = filesymname;
553 gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
556 /* For @plt symbols, also record a trampoline to the
557 destination symbol. The @plt symbol will be used in
558 disassembly, and the trampoline will be used when we are
559 trying to find the target. */
560 if (msym && ms_type == mst_text && type == ST_SYNTHETIC)
562 int len = strlen (sym->name);
564 if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0)
566 struct minimal_symbol *mtramp;
568 mtramp = record_minimal_symbol (sym->name, len - 4, 1,
570 mst_solib_trampoline,
571 sym->section, objfile);
574 MSYMBOL_SIZE (mtramp) = MSYMBOL_SIZE (msym);
575 mtramp->filename = filesymname;
576 gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp);
582 do_cleanups (back_to);
591 /* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
593 static struct build_id *
594 build_id_bfd_get (bfd *abfd)
596 struct build_id *retval;
598 if (!bfd_check_format (abfd, bfd_object)
599 || bfd_get_flavour (abfd) != bfd_target_elf_flavour
600 || elf_tdata (abfd)->build_id == NULL)
603 retval = xmalloc (sizeof *retval - 1 + elf_tdata (abfd)->build_id_size);
604 retval->size = elf_tdata (abfd)->build_id_size;
605 memcpy (retval->data, elf_tdata (abfd)->build_id, retval->size);
610 /* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */
613 build_id_verify (const char *filename, struct build_id *check)
616 struct build_id *found = NULL;
619 /* We expect to be silent on the non-existing files. */
620 abfd = bfd_open_maybe_remote (filename);
624 found = build_id_bfd_get (abfd);
627 warning (_("File \"%s\" has no build-id, file skipped"), filename);
628 else if (found->size != check->size
629 || memcmp (found->data, check->data, found->size) != 0)
630 warning (_("File \"%s\" has a different build-id, file skipped"),
635 gdb_bfd_close_or_warn (abfd);
643 build_id_to_debug_filename (struct build_id *build_id)
645 char *link, *debugdir, *retval = NULL;
647 /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
648 link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
649 + 2 * build_id->size + (sizeof ".debug" - 1) + 1);
651 /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
652 cause "/.build-id/..." lookups. */
654 debugdir = debug_file_directory;
657 char *s, *debugdir_end;
658 gdb_byte *data = build_id->data;
659 size_t size = build_id->size;
661 while (*debugdir == DIRNAME_SEPARATOR)
664 debugdir_end = strchr (debugdir, DIRNAME_SEPARATOR);
665 if (debugdir_end == NULL)
666 debugdir_end = &debugdir[strlen (debugdir)];
668 memcpy (link, debugdir, debugdir_end - debugdir);
669 s = &link[debugdir_end - debugdir];
670 s += sprintf (s, "/.build-id/");
674 s += sprintf (s, "%02x", (unsigned) *data++);
679 s += sprintf (s, "%02x", (unsigned) *data++);
680 strcpy (s, ".debug");
682 /* lrealpath() is expensive even for the usually non-existent files. */
683 if (access (link, F_OK) == 0)
684 retval = lrealpath (link);
686 if (retval != NULL && !build_id_verify (retval, build_id))
695 debugdir = debugdir_end;
697 while (*debugdir != 0);
703 find_separate_debug_file_by_buildid (struct objfile *objfile)
705 struct build_id *build_id;
707 build_id = build_id_bfd_get (objfile->obfd);
708 if (build_id != NULL)
712 build_id_name = build_id_to_debug_filename (build_id);
714 /* Prevent looping on a stripped .debug file. */
715 if (build_id_name != NULL
716 && filename_cmp (build_id_name, objfile->name) == 0)
718 warning (_("\"%s\": separate debug info file has no debug info"),
720 xfree (build_id_name);
722 else if (build_id_name != NULL)
723 return build_id_name;
728 /* Scan and build partial symbols for a symbol file.
729 We have been initialized by a call to elf_symfile_init, which
730 currently does nothing.
732 SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
733 in each section. We simplify it down to a single offset for all
736 This function only does the minimum work necessary for letting the
737 user "name" things symbolically; it does not read the entire symtab.
738 Instead, it reads the external and static symbols and puts them in partial
739 symbol tables. When more extensive information is requested of a
740 file, the corresponding partial symbol table is mutated into a full
741 fledged symbol table by going back and reading the symbols
744 We look for sections with specific names, to tell us what debug
745 format to look for: FIXME!!!
747 elfstab_build_psymtabs() handles STABS symbols;
748 mdebug_build_psymtabs() handles ECOFF debugging information.
750 Note that ELF files have a "minimal" symbol table, which looks a lot
751 like a COFF symbol table, but has only the minimal information necessary
752 for linking. We process this also, and use the information to
753 build gdb's minimal symbol table. This gives us some minimal debugging
754 capability even for files compiled without -g. */
757 elf_symfile_read (struct objfile *objfile, int symfile_flags)
759 bfd *abfd = objfile->obfd;
761 struct cleanup *back_to;
762 long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
763 asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
766 init_minimal_symbol_collection ();
767 back_to = make_cleanup_discard_minimal_symbols ();
769 memset ((char *) &ei, 0, sizeof (ei));
771 /* Allocate struct to keep track of the symfile. */
772 objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *)
773 xmalloc (sizeof (struct dbx_symfile_info));
774 memset ((char *) objfile->deprecated_sym_stab_info,
775 0, sizeof (struct dbx_symfile_info));
776 make_cleanup (free_elfinfo, (void *) objfile);
778 /* Process the normal ELF symbol table first. This may write some
779 chain of info into the dbx_symfile_info in
780 objfile->deprecated_sym_stab_info, which can later be used by
781 elfstab_offset_sections. */
783 storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
784 if (storage_needed < 0)
785 error (_("Can't read symbols from %s: %s"),
786 bfd_get_filename (objfile->obfd),
787 bfd_errmsg (bfd_get_error ()));
789 if (storage_needed > 0)
791 symbol_table = (asymbol **) xmalloc (storage_needed);
792 make_cleanup (xfree, symbol_table);
793 symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table);
796 error (_("Can't read symbols from %s: %s"),
797 bfd_get_filename (objfile->obfd),
798 bfd_errmsg (bfd_get_error ()));
800 elf_symtab_read (objfile, ST_REGULAR, symcount, symbol_table, 0);
803 /* Add the dynamic symbols. */
805 storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd);
807 if (storage_needed > 0)
809 /* Memory gets permanently referenced from ABFD after
810 bfd_get_synthetic_symtab so it must not get freed before ABFD gets.
811 It happens only in the case when elf_slurp_reloc_table sees
812 asection->relocation NULL. Determining which section is asection is
813 done by _bfd_elf_get_synthetic_symtab which is all a bfd
814 implementation detail, though. */
816 dyn_symbol_table = bfd_alloc (abfd, storage_needed);
817 dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd,
821 error (_("Can't read symbols from %s: %s"),
822 bfd_get_filename (objfile->obfd),
823 bfd_errmsg (bfd_get_error ()));
825 elf_symtab_read (objfile, ST_DYNAMIC, dynsymcount, dyn_symbol_table, 0);
828 /* Add synthetic symbols - for instance, names for any PLT entries. */
830 synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table,
831 dynsymcount, dyn_symbol_table,
835 asymbol **synth_symbol_table;
838 make_cleanup (xfree, synthsyms);
839 synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount);
840 for (i = 0; i < synthcount; i++)
841 synth_symbol_table[i] = synthsyms + i;
842 make_cleanup (xfree, synth_symbol_table);
843 elf_symtab_read (objfile, ST_SYNTHETIC, synthcount,
844 synth_symbol_table, 1);
847 /* Install any minimal symbols that have been collected as the current
848 minimal symbols for this objfile. The debug readers below this point
849 should not generate new minimal symbols; if they do it's their
850 responsibility to install them. "mdebug" appears to be the only one
851 which will do this. */
853 install_minimal_symbols (objfile);
854 do_cleanups (back_to);
856 /* Now process debugging information, which is contained in
857 special ELF sections. */
859 /* We first have to find them... */
860 bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei);
862 /* ELF debugging information is inserted into the psymtab in the
863 order of least informative first - most informative last. Since
864 the psymtab table is searched `most recent insertion first' this
865 increases the probability that more detailed debug information
866 for a section is found.
868 For instance, an object file might contain both .mdebug (XCOFF)
869 and .debug_info (DWARF2) sections then .mdebug is inserted first
870 (searched last) and DWARF2 is inserted last (searched first). If
871 we don't do this then the XCOFF info is found first - for code in
872 an included file XCOFF info is useless. */
876 const struct ecoff_debug_swap *swap;
878 /* .mdebug section, presumably holding ECOFF debugging
880 swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
882 elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect);
888 /* Stab sections have an associated string table that looks like
889 a separate section. */
890 str_sect = bfd_get_section_by_name (abfd, ".stabstr");
892 /* FIXME should probably warn about a stab section without a stabstr. */
894 elfstab_build_psymtabs (objfile,
897 bfd_section_size (abfd, str_sect));
900 if (dwarf2_has_info (objfile))
902 if (dwarf2_initialize_objfile (objfile))
903 objfile->sf = &elf_sym_fns_gdb_index;
906 /* It is ok to do this even if the stabs reader made some
907 partial symbols, because OBJF_PSYMTABS_READ has not been
908 set, and so our lazy reader function will still be called
910 objfile->sf = &elf_sym_fns_lazy_psyms;
913 /* If the file has its own symbol tables it has no separate debug
914 info. `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to
915 SYMTABS/PSYMTABS. `.gnu_debuglink' may no longer be present with
916 `.note.gnu.build-id'. */
917 else if (!objfile_has_partial_symbols (objfile))
921 debugfile = find_separate_debug_file_by_buildid (objfile);
923 if (debugfile == NULL)
924 debugfile = find_separate_debug_file_by_debuglink (objfile);
928 bfd *abfd = symfile_bfd_open (debugfile);
930 symbol_file_add_separate (abfd, symfile_flags, objfile);
936 /* Callback to lazily read psymtabs. */
939 read_psyms (struct objfile *objfile)
941 if (dwarf2_has_info (objfile))
942 dwarf2_build_psymtabs (objfile);
945 /* This cleans up the objfile's deprecated_sym_stab_info pointer, and
946 the chain of stab_section_info's, that might be dangling from
950 free_elfinfo (void *objp)
952 struct objfile *objfile = (struct objfile *) objp;
953 struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info;
954 struct stab_section_info *ssi, *nssi;
956 ssi = dbxinfo->stab_section_info;
964 dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */
968 /* Initialize anything that needs initializing when a completely new symbol
969 file is specified (not just adding some symbols from another file, e.g. a
972 We reinitialize buildsym, since we may be reading stabs from an ELF
976 elf_new_init (struct objfile *ignore)
978 stabsread_new_init ();
979 buildsym_new_init ();
982 /* Perform any local cleanups required when we are done with a particular
983 objfile. I.E, we are in the process of discarding all symbol information
984 for an objfile, freeing up all memory held for it, and unlinking the
985 objfile struct from the global list of known objfiles. */
988 elf_symfile_finish (struct objfile *objfile)
990 if (objfile->deprecated_sym_stab_info != NULL)
992 xfree (objfile->deprecated_sym_stab_info);
995 dwarf2_free_objfile (objfile);
998 /* ELF specific initialization routine for reading symbols.
1000 It is passed a pointer to a struct sym_fns which contains, among other
1001 things, the BFD for the file whose symbols are being read, and a slot for
1002 a pointer to "private data" which we can fill with goodies.
1004 For now at least, we have nothing in particular to do, so this function is
1008 elf_symfile_init (struct objfile *objfile)
1010 /* ELF objects may be reordered, so set OBJF_REORDERED. If we
1011 find this causes a significant slowdown in gdb then we could
1012 set it in the debug symbol readers only when necessary. */
1013 objfile->flags |= OBJF_REORDERED;
1016 /* When handling an ELF file that contains Sun STABS debug info,
1017 some of the debug info is relative to the particular chunk of the
1018 section that was generated in its individual .o file. E.g.
1019 offsets to static variables are relative to the start of the data
1020 segment *for that module before linking*. This information is
1021 painfully squirreled away in the ELF symbol table as local symbols
1022 with wierd names. Go get 'em when needed. */
1025 elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst)
1027 const char *filename = pst->filename;
1028 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
1029 struct stab_section_info *maybe = dbx->stab_section_info;
1030 struct stab_section_info *questionable = 0;
1033 /* The ELF symbol info doesn't include path names, so strip the path
1034 (if any) from the psymtab filename. */
1035 filename = lbasename (filename);
1037 /* FIXME: This linear search could speed up significantly
1038 if it was chained in the right order to match how we search it,
1039 and if we unchained when we found a match. */
1040 for (; maybe; maybe = maybe->next)
1042 if (filename[0] == maybe->filename[0]
1043 && filename_cmp (filename, maybe->filename) == 0)
1045 /* We found a match. But there might be several source files
1046 (from different directories) with the same name. */
1047 if (0 == maybe->found)
1049 questionable = maybe; /* Might use it later. */
1053 if (maybe == 0 && questionable != 0)
1055 complaint (&symfile_complaints,
1056 _("elf/stab section information questionable for %s"),
1058 maybe = questionable;
1063 /* Found it! Allocate a new psymtab struct, and fill it in. */
1065 pst->section_offsets = (struct section_offsets *)
1066 obstack_alloc (&objfile->objfile_obstack,
1067 SIZEOF_N_SECTION_OFFSETS (objfile->num_sections));
1068 for (i = 0; i < maybe->num_sections; i++)
1069 (pst->section_offsets)->offsets[i] = maybe->sections[i];
1073 /* We were unable to find any offsets for this file. Complain. */
1074 if (dbx->stab_section_info) /* If there *is* any info, */
1075 complaint (&symfile_complaints,
1076 _("elf/stab section information missing for %s"), filename);
1079 /* Register that we are able to handle ELF object file formats. */
1081 static const struct sym_fns elf_sym_fns =
1083 bfd_target_elf_flavour,
1084 elf_new_init, /* init anything gbl to entire symtab */
1085 elf_symfile_init, /* read initial info, setup for sym_read() */
1086 elf_symfile_read, /* read a symbol file into symtab */
1087 NULL, /* sym_read_psymbols */
1088 elf_symfile_finish, /* finished with file, cleanup */
1089 default_symfile_offsets, /* Translate ext. to int. relocation */
1090 elf_symfile_segments, /* Get segment information from a file. */
1092 default_symfile_relocate, /* Relocate a debug section. */
1096 /* The same as elf_sym_fns, but not registered and lazily reads
1099 static const struct sym_fns elf_sym_fns_lazy_psyms =
1101 bfd_target_elf_flavour,
1102 elf_new_init, /* init anything gbl to entire symtab */
1103 elf_symfile_init, /* read initial info, setup for sym_read() */
1104 elf_symfile_read, /* read a symbol file into symtab */
1105 read_psyms, /* sym_read_psymbols */
1106 elf_symfile_finish, /* finished with file, cleanup */
1107 default_symfile_offsets, /* Translate ext. to int. relocation */
1108 elf_symfile_segments, /* Get segment information from a file. */
1110 default_symfile_relocate, /* Relocate a debug section. */
1114 /* The same as elf_sym_fns, but not registered and uses the
1115 DWARF-specific GNU index rather than psymtab. */
1116 static const struct sym_fns elf_sym_fns_gdb_index =
1118 bfd_target_elf_flavour,
1119 elf_new_init, /* init anything gbl to entire symab */
1120 elf_symfile_init, /* read initial info, setup for sym_red() */
1121 elf_symfile_read, /* read a symbol file into symtab */
1122 NULL, /* sym_read_psymbols */
1123 elf_symfile_finish, /* finished with file, cleanup */
1124 default_symfile_offsets, /* Translate ext. to int. relocatin */
1125 elf_symfile_segments, /* Get segment information from a file. */
1127 default_symfile_relocate, /* Relocate a debug section. */
1128 &dwarf2_gdb_index_functions
1132 _initialize_elfread (void)
1134 add_symtab_fns (&elf_sym_fns);