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
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 extern void _initialize_elfread (void);
42 /* The struct elfinfo is available only during ELF symbol table and
43 psymtab reading. It is destroyed at the completion of psymtab-reading.
44 It's local to elf_symfile_read. */
48 asection *stabsect; /* Section pointer for .stab section */
49 asection *stabindexsect; /* Section pointer for .stab.index section */
50 asection *mdebugsect; /* Section pointer for .mdebug section */
53 static void free_elfinfo (void *);
55 /* Locate the segments in ABFD. */
57 static struct symfile_segment_data *
58 elf_symfile_segments (bfd *abfd)
60 Elf_Internal_Phdr *phdrs, **segments;
62 int num_phdrs, num_segments, num_sections, i;
64 struct symfile_segment_data *data;
66 phdrs_size = bfd_get_elf_phdr_upper_bound (abfd);
70 phdrs = alloca (phdrs_size);
71 num_phdrs = bfd_get_elf_phdrs (abfd, phdrs);
76 segments = alloca (sizeof (Elf_Internal_Phdr *) * num_phdrs);
77 for (i = 0; i < num_phdrs; i++)
78 if (phdrs[i].p_type == PT_LOAD)
79 segments[num_segments++] = &phdrs[i];
81 if (num_segments == 0)
84 data = XZALLOC (struct symfile_segment_data);
85 data->num_segments = num_segments;
86 data->segment_bases = XCALLOC (num_segments, CORE_ADDR);
87 data->segment_sizes = XCALLOC (num_segments, CORE_ADDR);
89 for (i = 0; i < num_segments; i++)
91 data->segment_bases[i] = segments[i]->p_vaddr;
92 data->segment_sizes[i] = segments[i]->p_memsz;
95 num_sections = bfd_count_sections (abfd);
96 data->segment_info = XCALLOC (num_sections, int);
98 for (i = 0, sect = abfd->sections; sect != NULL; i++, sect = sect->next)
103 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
106 vma = bfd_get_section_vma (abfd, sect);
108 for (j = 0; j < num_segments; j++)
109 if (segments[j]->p_memsz > 0
110 && vma >= segments[j]->p_vaddr
111 && (vma - segments[j]->p_vaddr) < segments[j]->p_memsz)
113 data->segment_info[i] = j + 1;
117 /* We should have found a segment for every non-empty section.
118 If we haven't, we will not relocate this section by any
119 offsets we apply to the segments. As an exception, do not
120 warn about SHT_NOBITS sections; in normal ELF execution
121 environments, SHT_NOBITS means zero-initialized and belongs
122 in a segment, but in no-OS environments some tools (e.g. ARM
123 RealView) use SHT_NOBITS for uninitialized data. Since it is
124 uninitialized, it doesn't need a program header. Such
125 binaries are not relocatable. */
126 if (bfd_get_section_size (sect) > 0 && j == num_segments
127 && (bfd_get_section_flags (abfd, sect) & SEC_LOAD) != 0)
128 warning (_("Loadable segment \"%s\" outside of ELF segments"),
129 bfd_section_name (abfd, sect));
135 /* We are called once per section from elf_symfile_read. We
136 need to examine each section we are passed, check to see
137 if it is something we are interested in processing, and
138 if so, stash away some access information for the section.
140 For now we recognize the dwarf debug information sections and
141 line number sections from matching their section names. The
142 ELF definition is no real help here since it has no direct
143 knowledge of DWARF (by design, so any debugging format can be
146 We also recognize the ".stab" sections used by the Sun compilers
147 released with Solaris 2.
149 FIXME: The section names should not be hardwired strings (what
150 should they be? I don't think most object file formats have enough
151 section flags to specify what kind of debug section it is
155 elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip)
159 ei = (struct elfinfo *) eip;
160 if (strcmp (sectp->name, ".stab") == 0)
162 ei->stabsect = sectp;
164 else if (strcmp (sectp->name, ".stab.index") == 0)
166 ei->stabindexsect = sectp;
168 else if (strcmp (sectp->name, ".mdebug") == 0)
170 ei->mdebugsect = sectp;
174 static struct minimal_symbol *
175 record_minimal_symbol (const char *name, int name_len, int copy_name,
177 enum minimal_symbol_type ms_type,
178 asection *bfd_section, struct objfile *objfile)
180 struct gdbarch *gdbarch = get_objfile_arch (objfile);
182 if (ms_type == mst_text || ms_type == mst_file_text)
183 address = gdbarch_smash_text_address (gdbarch, address);
185 return prim_record_minimal_symbol_full (name, name_len, copy_name, address,
186 ms_type, bfd_section->index,
187 bfd_section, objfile);
194 elf_symtab_read -- read the symbol table of an ELF file
198 void elf_symtab_read (struct objfile *objfile, int type,
199 long number_of_symbols, asymbol **symbol_table)
203 Given an objfile, a symbol table, and a flag indicating whether the
204 symbol table contains regular, dynamic, or synthetic symbols, add all
205 the global function and data symbols to the minimal symbol table.
207 In stabs-in-ELF, as implemented by Sun, there are some local symbols
208 defined in the ELF symbol table, which can be used to locate
209 the beginnings of sections from each ".o" file that was linked to
210 form the executable objfile. We gather any such info and record it
211 in data structures hung off the objfile's private data.
217 #define ST_SYNTHETIC 2
220 elf_symtab_read (struct objfile *objfile, int type,
221 long number_of_symbols, asymbol **symbol_table,
224 struct gdbarch *gdbarch = get_objfile_arch (objfile);
230 enum minimal_symbol_type ms_type;
231 /* If sectinfo is nonNULL, it contains section info that should end up
232 filed in the objfile. */
233 struct stab_section_info *sectinfo = NULL;
234 /* If filesym is nonzero, it points to a file symbol, but we haven't
235 seen any section info for it yet. */
236 asymbol *filesym = 0;
237 /* Name of filesym. This is either a constant string or is saved on
238 the objfile's obstack. */
239 char *filesymname = "";
240 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
241 int stripped = (bfd_get_symcount (objfile->obfd) == 0);
243 for (i = 0; i < number_of_symbols; i++)
245 sym = symbol_table[i];
246 if (sym->name == NULL || *sym->name == '\0')
248 /* Skip names that don't exist (shouldn't happen), or names
249 that are null strings (may happen). */
253 /* Skip "special" symbols, e.g. ARM mapping symbols. These are
254 symbols which do not correspond to objects in the symbol table,
255 but have some other target-specific meaning. */
256 if (bfd_is_target_special_symbol (objfile->obfd, sym))
258 if (gdbarch_record_special_symbol_p (gdbarch))
259 gdbarch_record_special_symbol (gdbarch, objfile, sym);
263 offset = ANOFFSET (objfile->section_offsets, sym->section->index);
264 if (type == ST_DYNAMIC
265 && sym->section == &bfd_und_section
266 && (sym->flags & BSF_FUNCTION))
268 struct minimal_symbol *msym;
269 bfd *abfd = objfile->obfd;
272 /* Symbol is a reference to a function defined in
274 If its value is non zero then it is usually the address
275 of the corresponding entry in the procedure linkage table,
276 plus the desired section offset.
277 If its value is zero then the dynamic linker has to resolve
278 the symbol. We are unable to find any meaningful address
279 for this symbol in the executable file, so we skip it. */
280 symaddr = sym->value;
284 /* sym->section is the undefined section. However, we want to
285 record the section where the PLT stub resides with the
286 minimal symbol. Search the section table for the one that
287 covers the stub's address. */
288 for (sect = abfd->sections; sect != NULL; sect = sect->next)
290 if ((bfd_get_section_flags (abfd, sect) & SEC_ALLOC) == 0)
293 if (symaddr >= bfd_get_section_vma (abfd, sect)
294 && symaddr < bfd_get_section_vma (abfd, sect)
295 + bfd_get_section_size (sect))
301 symaddr += ANOFFSET (objfile->section_offsets, sect->index);
303 msym = record_minimal_symbol
304 (sym->name, strlen (sym->name), copy_names,
305 symaddr, mst_solib_trampoline, sect, objfile);
307 msym->filename = filesymname;
311 /* If it is a nonstripped executable, do not enter dynamic
312 symbols, as the dynamic symbol table is usually a subset
313 of the main symbol table. */
314 if (type == ST_DYNAMIC && !stripped)
316 if (sym->flags & BSF_FILE)
318 /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
319 Chain any old one onto the objfile; remember new sym. */
320 if (sectinfo != NULL)
322 sectinfo->next = dbx->stab_section_info;
323 dbx->stab_section_info = sectinfo;
328 obsavestring ((char *) filesym->name, strlen (filesym->name),
329 &objfile->objfile_obstack);
331 else if (sym->flags & BSF_SECTION_SYM)
333 else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
335 struct minimal_symbol *msym;
337 /* Select global/local/weak symbols. Note that bfd puts abs
338 symbols in their own section, so all symbols we are
339 interested in will have a section. */
340 /* Bfd symbols are section relative. */
341 symaddr = sym->value + sym->section->vma;
342 /* Relocate all non-absolute and non-TLS symbols by the
344 if (sym->section != &bfd_abs_section
345 && !(sym->section->flags & SEC_THREAD_LOCAL))
349 /* For non-absolute symbols, use the type of the section
350 they are relative to, to intuit text/data. Bfd provides
351 no way of figuring this out for absolute symbols. */
352 if (sym->section == &bfd_abs_section)
354 /* This is a hack to get the minimal symbol type
355 right for Irix 5, which has absolute addresses
356 with special section indices for dynamic symbols.
358 NOTE: uweigand-20071112: Synthetic symbols do not
359 have an ELF-private part, so do not touch those. */
360 unsigned int shndx = type == ST_SYNTHETIC ? 0 :
361 ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
371 case SHN_MIPS_ACOMMON:
378 /* If it is an Irix dynamic symbol, skip section name
379 symbols, relocate all others by section offset. */
380 if (ms_type != mst_abs)
382 if (sym->name[0] == '.')
387 else if (sym->section->flags & SEC_CODE)
389 if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
393 else if ((sym->name[0] == '.' && sym->name[1] == 'L')
394 || ((sym->flags & BSF_LOCAL)
395 && sym->name[0] == '$'
396 && sym->name[1] == 'L'))
397 /* Looks like a compiler-generated label. Skip
398 it. The assembler should be skipping these (to
399 keep executables small), but apparently with
400 gcc on the (deleted) delta m88k SVR4, it loses.
401 So to have us check too should be harmless (but
402 I encourage people to fix this in the assembler
403 instead of adding checks here). */
407 ms_type = mst_file_text;
410 else if (sym->section->flags & SEC_ALLOC)
412 if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
414 if (sym->section->flags & SEC_LOAD)
423 else if (sym->flags & BSF_LOCAL)
425 /* Named Local variable in a Data section.
426 Check its name for stabs-in-elf. */
427 int special_local_sect;
428 if (strcmp ("Bbss.bss", sym->name) == 0)
429 special_local_sect = SECT_OFF_BSS (objfile);
430 else if (strcmp ("Ddata.data", sym->name) == 0)
431 special_local_sect = SECT_OFF_DATA (objfile);
432 else if (strcmp ("Drodata.rodata", sym->name) == 0)
433 special_local_sect = SECT_OFF_RODATA (objfile);
435 special_local_sect = -1;
436 if (special_local_sect >= 0)
438 /* Found a special local symbol. Allocate a
439 sectinfo, if needed, and fill it in. */
440 if (sectinfo == NULL)
445 max_index = SECT_OFF_BSS (objfile);
446 if (objfile->sect_index_data > max_index)
447 max_index = objfile->sect_index_data;
448 if (objfile->sect_index_rodata > max_index)
449 max_index = objfile->sect_index_rodata;
451 /* max_index is the largest index we'll
452 use into this array, so we must
453 allocate max_index+1 elements for it.
454 However, 'struct stab_section_info'
455 already includes one element, so we
456 need to allocate max_index aadditional
458 size = (sizeof (struct stab_section_info)
459 + (sizeof (CORE_ADDR)
461 sectinfo = (struct stab_section_info *)
463 memset (sectinfo, 0, size);
464 sectinfo->num_sections = max_index;
467 complaint (&symfile_complaints,
468 _("elf/stab section information %s without a preceding file symbol"),
474 (char *) filesym->name;
477 if (sectinfo->sections[special_local_sect] != 0)
478 complaint (&symfile_complaints,
479 _("duplicated elf/stab section information for %s"),
481 /* BFD symbols are section relative. */
482 symaddr = sym->value + sym->section->vma;
483 /* Relocate non-absolute symbols by the
485 if (sym->section != &bfd_abs_section)
487 sectinfo->sections[special_local_sect] = symaddr;
488 /* The special local symbols don't go in the
489 minimal symbol table, so ignore this one. */
492 /* Not a special stabs-in-elf symbol, do regular
493 symbol processing. */
494 if (sym->section->flags & SEC_LOAD)
496 ms_type = mst_file_data;
500 ms_type = mst_file_bss;
505 ms_type = mst_unknown;
510 /* FIXME: Solaris2 shared libraries include lots of
511 odd "absolute" and "undefined" symbols, that play
512 hob with actions like finding what function the PC
513 is in. Ignore them if they aren't text, data, or bss. */
514 /* ms_type = mst_unknown; */
515 continue; /* Skip this symbol. */
517 msym = record_minimal_symbol
518 (sym->name, strlen (sym->name), copy_names, symaddr,
519 ms_type, sym->section, objfile);
523 /* Pass symbol size field in via BFD. FIXME!!! */
524 elf_symbol_type *elf_sym;
526 /* NOTE: uweigand-20071112: A synthetic symbol does not have an
527 ELF-private part. However, in some cases (e.g. synthetic
528 'dot' symbols on ppc64) the udata.p entry is set to point back
529 to the original ELF symbol it was derived from. Get the size
531 if (type != ST_SYNTHETIC)
532 elf_sym = (elf_symbol_type *) sym;
534 elf_sym = (elf_symbol_type *) sym->udata.p;
537 MSYMBOL_SIZE(msym) = elf_sym->internal_elf_sym.st_size;
539 msym->filename = filesymname;
540 gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
543 /* For @plt symbols, also record a trampoline to the
544 destination symbol. The @plt symbol will be used in
545 disassembly, and the trampoline will be used when we are
546 trying to find the target. */
547 if (msym && ms_type == mst_text && type == ST_SYNTHETIC)
549 int len = strlen (sym->name);
551 if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0)
553 struct minimal_symbol *mtramp;
555 mtramp = record_minimal_symbol (sym->name, len - 4, 1,
557 mst_solib_trampoline,
558 sym->section, objfile);
561 MSYMBOL_SIZE (mtramp) = MSYMBOL_SIZE (msym);
562 mtramp->filename = filesymname;
563 gdbarch_elf_make_msymbol_special (gdbarch, sym, mtramp);
577 /* Locate NT_GNU_BUILD_ID from ABFD and return its content. */
579 static struct build_id *
580 build_id_bfd_get (bfd *abfd)
582 struct build_id *retval;
584 if (!bfd_check_format (abfd, bfd_object)
585 || bfd_get_flavour (abfd) != bfd_target_elf_flavour
586 || elf_tdata (abfd)->build_id == NULL)
589 retval = xmalloc (sizeof *retval - 1 + elf_tdata (abfd)->build_id_size);
590 retval->size = elf_tdata (abfd)->build_id_size;
591 memcpy (retval->data, elf_tdata (abfd)->build_id, retval->size);
596 /* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value. */
599 build_id_verify (const char *filename, struct build_id *check)
602 struct build_id *found = NULL;
605 /* We expect to be silent on the non-existing files. */
606 abfd = bfd_open_maybe_remote (filename);
610 found = build_id_bfd_get (abfd);
613 warning (_("File \"%s\" has no build-id, file skipped"), filename);
614 else if (found->size != check->size
615 || memcmp (found->data, check->data, found->size) != 0)
616 warning (_("File \"%s\" has a different build-id, file skipped"), filename);
620 if (!bfd_close (abfd))
621 warning (_("cannot close \"%s\": %s"), filename,
622 bfd_errmsg (bfd_get_error ()));
630 build_id_to_debug_filename (struct build_id *build_id)
632 char *link, *debugdir, *retval = NULL;
634 /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
635 link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
636 + 2 * build_id->size + (sizeof ".debug" - 1) + 1);
638 /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
639 cause "/.build-id/..." lookups. */
641 debugdir = debug_file_directory;
644 char *s, *debugdir_end;
645 gdb_byte *data = build_id->data;
646 size_t size = build_id->size;
648 while (*debugdir == DIRNAME_SEPARATOR)
651 debugdir_end = strchr (debugdir, DIRNAME_SEPARATOR);
652 if (debugdir_end == NULL)
653 debugdir_end = &debugdir[strlen (debugdir)];
655 memcpy (link, debugdir, debugdir_end - debugdir);
656 s = &link[debugdir_end - debugdir];
657 s += sprintf (s, "/.build-id/");
661 s += sprintf (s, "%02x", (unsigned) *data++);
666 s += sprintf (s, "%02x", (unsigned) *data++);
667 strcpy (s, ".debug");
669 /* lrealpath() is expensive even for the usually non-existent files. */
670 if (access (link, F_OK) == 0)
671 retval = lrealpath (link);
673 if (retval != NULL && !build_id_verify (retval, build_id))
682 debugdir = debugdir_end;
684 while (*debugdir != 0);
690 find_separate_debug_file_by_buildid (struct objfile *objfile)
693 char *basename, *name_copy, *debugdir;
695 char *debugfile = NULL;
696 char *canon_name = NULL;
697 bfd_size_type debuglink_size;
700 struct build_id *build_id;
702 build_id = build_id_bfd_get (objfile->obfd);
703 if (build_id != NULL)
707 build_id_name = build_id_to_debug_filename (build_id);
709 /* Prevent looping on a stripped .debug file. */
710 if (build_id_name != NULL && strcmp (build_id_name, objfile->name) == 0)
712 warning (_("\"%s\": separate debug info file has no debug info"),
714 xfree (build_id_name);
716 else if (build_id_name != NULL)
717 return build_id_name;
722 /* Scan and build partial symbols for a symbol file.
723 We have been initialized by a call to elf_symfile_init, which
724 currently does nothing.
726 SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
727 in each section. We simplify it down to a single offset for all
730 This function only does the minimum work necessary for letting the
731 user "name" things symbolically; it does not read the entire symtab.
732 Instead, it reads the external and static symbols and puts them in partial
733 symbol tables. When more extensive information is requested of a
734 file, the corresponding partial symbol table is mutated into a full
735 fledged symbol table by going back and reading the symbols
738 We look for sections with specific names, to tell us what debug
739 format to look for: FIXME!!!
741 elfstab_build_psymtabs() handles STABS symbols;
742 mdebug_build_psymtabs() handles ECOFF debugging information.
744 Note that ELF files have a "minimal" symbol table, which looks a lot
745 like a COFF symbol table, but has only the minimal information necessary
746 for linking. We process this also, and use the information to
747 build gdb's minimal symbol table. This gives us some minimal debugging
748 capability even for files compiled without -g. */
751 elf_symfile_read (struct objfile *objfile, int symfile_flags)
753 bfd *abfd = objfile->obfd;
755 struct cleanup *back_to;
757 long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
758 asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
761 init_minimal_symbol_collection ();
762 back_to = make_cleanup_discard_minimal_symbols ();
764 memset ((char *) &ei, 0, sizeof (ei));
766 /* Allocate struct to keep track of the symfile */
767 objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *)
768 xmalloc (sizeof (struct dbx_symfile_info));
769 memset ((char *) objfile->deprecated_sym_stab_info, 0, sizeof (struct dbx_symfile_info));
770 make_cleanup (free_elfinfo, (void *) objfile);
772 /* Process the normal ELF symbol table first. This may write some
773 chain of info into the dbx_symfile_info in objfile->deprecated_sym_stab_info,
774 which can later be used by elfstab_offset_sections. */
776 storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
777 if (storage_needed < 0)
778 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd),
779 bfd_errmsg (bfd_get_error ()));
781 if (storage_needed > 0)
783 symbol_table = (asymbol **) xmalloc (storage_needed);
784 make_cleanup (xfree, symbol_table);
785 symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table);
788 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd),
789 bfd_errmsg (bfd_get_error ()));
791 elf_symtab_read (objfile, ST_REGULAR, symcount, symbol_table, 0);
794 /* Add the dynamic symbols. */
796 storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd);
798 if (storage_needed > 0)
800 dyn_symbol_table = (asymbol **) xmalloc (storage_needed);
801 make_cleanup (xfree, dyn_symbol_table);
802 dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd,
806 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd),
807 bfd_errmsg (bfd_get_error ()));
809 elf_symtab_read (objfile, ST_DYNAMIC, dynsymcount, dyn_symbol_table, 0);
812 /* Add synthetic symbols - for instance, names for any PLT entries. */
814 synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table,
815 dynsymcount, dyn_symbol_table,
819 asymbol **synth_symbol_table;
822 make_cleanup (xfree, synthsyms);
823 synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount);
824 for (i = 0; i < synthcount; i++)
825 synth_symbol_table[i] = synthsyms + i;
826 make_cleanup (xfree, synth_symbol_table);
827 elf_symtab_read (objfile, ST_SYNTHETIC, synthcount, synth_symbol_table, 1);
830 /* Install any minimal symbols that have been collected as the current
831 minimal symbols for this objfile. The debug readers below this point
832 should not generate new minimal symbols; if they do it's their
833 responsibility to install them. "mdebug" appears to be the only one
834 which will do this. */
836 install_minimal_symbols (objfile);
837 do_cleanups (back_to);
839 /* Now process debugging information, which is contained in
840 special ELF sections. */
842 /* We first have to find them... */
843 bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei);
845 /* ELF debugging information is inserted into the psymtab in the
846 order of least informative first - most informative last. Since
847 the psymtab table is searched `most recent insertion first' this
848 increases the probability that more detailed debug information
849 for a section is found.
851 For instance, an object file might contain both .mdebug (XCOFF)
852 and .debug_info (DWARF2) sections then .mdebug is inserted first
853 (searched last) and DWARF2 is inserted last (searched first). If
854 we don't do this then the XCOFF info is found first - for code in
855 an included file XCOFF info is useless. */
859 const struct ecoff_debug_swap *swap;
861 /* .mdebug section, presumably holding ECOFF debugging
863 swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
865 elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect);
871 /* Stab sections have an associated string table that looks like
872 a separate section. */
873 str_sect = bfd_get_section_by_name (abfd, ".stabstr");
875 /* FIXME should probably warn about a stab section without a stabstr. */
877 elfstab_build_psymtabs (objfile,
880 bfd_section_size (abfd, str_sect));
882 if (dwarf2_has_info (objfile))
884 /* DWARF 2 sections */
885 dwarf2_build_psymtabs (objfile);
888 /* FIXME: kettenis/20030504: This still needs to be integrated with
889 dwarf2read.c in a better way. */
890 dwarf2_build_frame_info (objfile);
892 /* If the file has its own symbol tables it has no separate debug info.
893 `.dynsym'/`.symtab' go to MSYMBOLS, `.debug_info' goes to SYMTABS/PSYMTABS.
894 `.gnu_debuglink' may no longer be present with `.note.gnu.build-id'. */
895 if (!objfile_has_partial_symbols (objfile))
899 debugfile = find_separate_debug_file_by_buildid (objfile);
901 if (debugfile == NULL)
902 debugfile = find_separate_debug_file_by_debuglink (objfile);
906 bfd *abfd = symfile_bfd_open (debugfile);
907 symbol_file_add_separate (abfd, symfile_flags, objfile);
913 /* This cleans up the objfile's deprecated_sym_stab_info pointer, and
914 the chain of stab_section_info's, that might be dangling from
918 free_elfinfo (void *objp)
920 struct objfile *objfile = (struct objfile *) objp;
921 struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info;
922 struct stab_section_info *ssi, *nssi;
924 ssi = dbxinfo->stab_section_info;
932 dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */
936 /* Initialize anything that needs initializing when a completely new symbol
937 file is specified (not just adding some symbols from another file, e.g. a
940 We reinitialize buildsym, since we may be reading stabs from an ELF file. */
943 elf_new_init (struct objfile *ignore)
945 stabsread_new_init ();
946 buildsym_new_init ();
949 /* Perform any local cleanups required when we are done with a particular
950 objfile. I.E, we are in the process of discarding all symbol information
951 for an objfile, freeing up all memory held for it, and unlinking the
952 objfile struct from the global list of known objfiles. */
955 elf_symfile_finish (struct objfile *objfile)
957 if (objfile->deprecated_sym_stab_info != NULL)
959 xfree (objfile->deprecated_sym_stab_info);
962 dwarf2_free_objfile (objfile);
965 /* ELF specific initialization routine for reading symbols.
967 It is passed a pointer to a struct sym_fns which contains, among other
968 things, the BFD for the file whose symbols are being read, and a slot for
969 a pointer to "private data" which we can fill with goodies.
971 For now at least, we have nothing in particular to do, so this function is
975 elf_symfile_init (struct objfile *objfile)
977 /* ELF objects may be reordered, so set OBJF_REORDERED. If we
978 find this causes a significant slowdown in gdb then we could
979 set it in the debug symbol readers only when necessary. */
980 objfile->flags |= OBJF_REORDERED;
983 /* When handling an ELF file that contains Sun STABS debug info,
984 some of the debug info is relative to the particular chunk of the
985 section that was generated in its individual .o file. E.g.
986 offsets to static variables are relative to the start of the data
987 segment *for that module before linking*. This information is
988 painfully squirreled away in the ELF symbol table as local symbols
989 with wierd names. Go get 'em when needed. */
992 elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst)
994 char *filename = pst->filename;
995 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
996 struct stab_section_info *maybe = dbx->stab_section_info;
997 struct stab_section_info *questionable = 0;
1001 /* The ELF symbol info doesn't include path names, so strip the path
1002 (if any) from the psymtab filename. */
1003 while (0 != (p = strchr (filename, '/')))
1006 /* FIXME: This linear search could speed up significantly
1007 if it was chained in the right order to match how we search it,
1008 and if we unchained when we found a match. */
1009 for (; maybe; maybe = maybe->next)
1011 if (filename[0] == maybe->filename[0]
1012 && strcmp (filename, maybe->filename) == 0)
1014 /* We found a match. But there might be several source files
1015 (from different directories) with the same name. */
1016 if (0 == maybe->found)
1018 questionable = maybe; /* Might use it later. */
1022 if (maybe == 0 && questionable != 0)
1024 complaint (&symfile_complaints,
1025 _("elf/stab section information questionable for %s"), filename);
1026 maybe = questionable;
1031 /* Found it! Allocate a new psymtab struct, and fill it in. */
1033 pst->section_offsets = (struct section_offsets *)
1034 obstack_alloc (&objfile->objfile_obstack,
1035 SIZEOF_N_SECTION_OFFSETS (objfile->num_sections));
1036 for (i = 0; i < maybe->num_sections; i++)
1037 (pst->section_offsets)->offsets[i] = maybe->sections[i];
1041 /* We were unable to find any offsets for this file. Complain. */
1042 if (dbx->stab_section_info) /* If there *is* any info, */
1043 complaint (&symfile_complaints,
1044 _("elf/stab section information missing for %s"), filename);
1047 /* Register that we are able to handle ELF object file formats. */
1049 static struct sym_fns elf_sym_fns =
1051 bfd_target_elf_flavour,
1052 elf_new_init, /* sym_new_init: init anything gbl to entire symtab */
1053 elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */
1054 elf_symfile_read, /* sym_read: read a symbol file into symtab */
1055 elf_symfile_finish, /* sym_finish: finished with file, cleanup */
1056 default_symfile_offsets, /* sym_offsets: Translate ext. to int. relocation */
1057 elf_symfile_segments, /* sym_segments: Get segment information from
1059 NULL, /* sym_read_linetable */
1060 NULL /* next: pointer to next struct sym_fns */
1064 _initialize_elfread (void)
1066 add_symtab_fns (&elf_sym_fns);