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[thirdparty/binutils-gdb.git] / gdb / elfread.c
1 /* Read ELF (Executable and Linking Format) object files for GDB.
2
3 Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
5
6 Written by Fred Fish at Cygnus Support.
7
8 This file is part of GDB.
9
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2 of the License, or
13 (at your option) any later version.
14
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 59 Temple Place - Suite 330,
23 Boston, MA 02111-1307, USA. */
24
25 #include "defs.h"
26 #include "bfd.h"
27 #include "gdb_string.h"
28 #include "elf-bfd.h"
29 #include "elf/mips.h"
30 #include "symtab.h"
31 #include "symfile.h"
32 #include "objfiles.h"
33 #include "buildsym.h"
34 #include "stabsread.h"
35 #include "gdb-stabs.h"
36 #include "complaints.h"
37 #include "demangle.h"
38
39 extern void _initialize_elfread (void);
40
41 /* The struct elfinfo is available only during ELF symbol table and
42 psymtab reading. It is destroyed at the completion of psymtab-reading.
43 It's local to elf_symfile_read. */
44
45 struct elfinfo
46 {
47 file_ptr dboffset; /* Offset to dwarf debug section */
48 unsigned int dbsize; /* Size of dwarf debug section */
49 file_ptr lnoffset; /* Offset to dwarf line number section */
50 unsigned int lnsize; /* Size of dwarf line number section */
51 asection *stabsect; /* Section pointer for .stab section */
52 asection *stabindexsect; /* Section pointer for .stab.index section */
53 asection *mdebugsect; /* Section pointer for .mdebug section */
54 };
55
56 static void free_elfinfo (void *);
57
58 /* We are called once per section from elf_symfile_read. We
59 need to examine each section we are passed, check to see
60 if it is something we are interested in processing, and
61 if so, stash away some access information for the section.
62
63 For now we recognize the dwarf debug information sections and
64 line number sections from matching their section names. The
65 ELF definition is no real help here since it has no direct
66 knowledge of DWARF (by design, so any debugging format can be
67 used).
68
69 We also recognize the ".stab" sections used by the Sun compilers
70 released with Solaris 2.
71
72 FIXME: The section names should not be hardwired strings (what
73 should they be? I don't think most object file formats have enough
74 section flags to specify what kind of debug section it is
75 -kingdon). */
76
77 static void
78 elf_locate_sections (bfd *ignore_abfd, asection *sectp, void *eip)
79 {
80 struct elfinfo *ei;
81
82 ei = (struct elfinfo *) eip;
83 if (strcmp (sectp->name, ".debug") == 0)
84 {
85 ei->dboffset = sectp->filepos;
86 ei->dbsize = bfd_get_section_size (sectp);
87 }
88 else if (strcmp (sectp->name, ".line") == 0)
89 {
90 ei->lnoffset = sectp->filepos;
91 ei->lnsize = bfd_get_section_size (sectp);
92 }
93 else if (strcmp (sectp->name, ".stab") == 0)
94 {
95 ei->stabsect = sectp;
96 }
97 else if (strcmp (sectp->name, ".stab.index") == 0)
98 {
99 ei->stabindexsect = sectp;
100 }
101 else if (strcmp (sectp->name, ".mdebug") == 0)
102 {
103 ei->mdebugsect = sectp;
104 }
105 }
106
107 static struct minimal_symbol *
108 record_minimal_symbol (char *name, CORE_ADDR address,
109 enum minimal_symbol_type ms_type,
110 asection *bfd_section, struct objfile *objfile)
111 {
112 if (ms_type == mst_text || ms_type == mst_file_text)
113 address = SMASH_TEXT_ADDRESS (address);
114
115 return prim_record_minimal_symbol_and_info
116 (name, address, ms_type, NULL, bfd_section->index, bfd_section, objfile);
117 }
118
119 /*
120
121 LOCAL FUNCTION
122
123 elf_symtab_read -- read the symbol table of an ELF file
124
125 SYNOPSIS
126
127 void elf_symtab_read (struct objfile *objfile, int dynamic,
128 long number_of_symbols, asymbol **symbol_table)
129
130 DESCRIPTION
131
132 Given an objfile, a symbol table, and a flag indicating whether the
133 symbol table contains dynamic symbols, add all the global function
134 and data symbols to the minimal symbol table.
135
136 In stabs-in-ELF, as implemented by Sun, there are some local symbols
137 defined in the ELF symbol table, which can be used to locate
138 the beginnings of sections from each ".o" file that was linked to
139 form the executable objfile. We gather any such info and record it
140 in data structures hung off the objfile's private data.
141
142 */
143
144 static void
145 elf_symtab_read (struct objfile *objfile, int dynamic,
146 long number_of_symbols, asymbol **symbol_table)
147 {
148 long storage_needed;
149 asymbol *sym;
150 long i;
151 CORE_ADDR symaddr;
152 CORE_ADDR offset;
153 enum minimal_symbol_type ms_type;
154 /* If sectinfo is nonNULL, it contains section info that should end up
155 filed in the objfile. */
156 struct stab_section_info *sectinfo = NULL;
157 /* If filesym is nonzero, it points to a file symbol, but we haven't
158 seen any section info for it yet. */
159 asymbol *filesym = 0;
160 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
161 /* Name of filesym, as saved on the objfile_obstack. */
162 char *filesymname = obsavestring ("", 0, &objfile->objfile_obstack);
163 #endif
164 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
165 int stripped = (bfd_get_symcount (objfile->obfd) == 0);
166
167 for (i = 0; i < number_of_symbols; i++)
168 {
169 sym = symbol_table[i];
170 if (sym->name == NULL || *sym->name == '\0')
171 {
172 /* Skip names that don't exist (shouldn't happen), or names
173 that are null strings (may happen). */
174 continue;
175 }
176
177 offset = ANOFFSET (objfile->section_offsets, sym->section->index);
178 if (dynamic
179 && sym->section == &bfd_und_section
180 && (sym->flags & BSF_FUNCTION))
181 {
182 struct minimal_symbol *msym;
183
184 /* Symbol is a reference to a function defined in
185 a shared library.
186 If its value is non zero then it is usually the address
187 of the corresponding entry in the procedure linkage table,
188 plus the desired section offset.
189 If its value is zero then the dynamic linker has to resolve
190 the symbol. We are unable to find any meaningful address
191 for this symbol in the executable file, so we skip it. */
192 symaddr = sym->value;
193 if (symaddr == 0)
194 continue;
195 symaddr += offset;
196 msym = record_minimal_symbol
197 ((char *) sym->name, symaddr,
198 mst_solib_trampoline, sym->section, objfile);
199 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
200 if (msym != NULL)
201 msym->filename = filesymname;
202 #endif
203 continue;
204 }
205
206 /* If it is a nonstripped executable, do not enter dynamic
207 symbols, as the dynamic symbol table is usually a subset
208 of the main symbol table. */
209 if (dynamic && !stripped)
210 continue;
211 if (sym->flags & BSF_FILE)
212 {
213 /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
214 Chain any old one onto the objfile; remember new sym. */
215 if (sectinfo != NULL)
216 {
217 sectinfo->next = dbx->stab_section_info;
218 dbx->stab_section_info = sectinfo;
219 sectinfo = NULL;
220 }
221 filesym = sym;
222 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
223 filesymname =
224 obsavestring ((char *) filesym->name, strlen (filesym->name),
225 &objfile->objfile_obstack);
226 #endif
227 }
228 else if (sym->flags & BSF_SECTION_SYM)
229 continue;
230 else if (sym->flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
231 {
232 struct minimal_symbol *msym;
233
234 /* Select global/local/weak symbols. Note that bfd puts abs
235 symbols in their own section, so all symbols we are
236 interested in will have a section. */
237 /* Bfd symbols are section relative. */
238 symaddr = sym->value + sym->section->vma;
239 /* Relocate all non-absolute symbols by the section offset. */
240 if (sym->section != &bfd_abs_section)
241 {
242 symaddr += offset;
243 }
244 /* For non-absolute symbols, use the type of the section
245 they are relative to, to intuit text/data. Bfd provides
246 no way of figuring this out for absolute symbols. */
247 if (sym->section == &bfd_abs_section)
248 {
249 /* This is a hack to get the minimal symbol type
250 right for Irix 5, which has absolute addresses
251 with special section indices for dynamic symbols. */
252 unsigned short shndx =
253 ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
254
255 switch (shndx)
256 {
257 case SHN_MIPS_TEXT:
258 ms_type = mst_text;
259 break;
260 case SHN_MIPS_DATA:
261 ms_type = mst_data;
262 break;
263 case SHN_MIPS_ACOMMON:
264 ms_type = mst_bss;
265 break;
266 default:
267 ms_type = mst_abs;
268 }
269
270 /* If it is an Irix dynamic symbol, skip section name
271 symbols, relocate all others by section offset. */
272 if (ms_type != mst_abs)
273 {
274 if (sym->name[0] == '.')
275 continue;
276 symaddr += offset;
277 }
278 }
279 else if (sym->section->flags & SEC_CODE)
280 {
281 if (sym->flags & BSF_GLOBAL)
282 {
283 ms_type = mst_text;
284 }
285 else if ((sym->name[0] == '.' && sym->name[1] == 'L')
286 || ((sym->flags & BSF_LOCAL)
287 && sym->name[0] == '$'
288 && sym->name[1] == 'L'))
289 /* Looks like a compiler-generated label. Skip
290 it. The assembler should be skipping these (to
291 keep executables small), but apparently with
292 gcc on the (deleted) delta m88k SVR4, it loses.
293 So to have us check too should be harmless (but
294 I encourage people to fix this in the assembler
295 instead of adding checks here). */
296 continue;
297 else
298 {
299 ms_type = mst_file_text;
300 }
301 }
302 else if (sym->section->flags & SEC_ALLOC)
303 {
304 if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
305 {
306 if (sym->section->flags & SEC_LOAD)
307 {
308 ms_type = mst_data;
309 }
310 else
311 {
312 ms_type = mst_bss;
313 }
314 }
315 else if (sym->flags & BSF_LOCAL)
316 {
317 /* Named Local variable in a Data section.
318 Check its name for stabs-in-elf. */
319 int special_local_sect;
320 if (strcmp ("Bbss.bss", sym->name) == 0)
321 special_local_sect = SECT_OFF_BSS (objfile);
322 else if (strcmp ("Ddata.data", sym->name) == 0)
323 special_local_sect = SECT_OFF_DATA (objfile);
324 else if (strcmp ("Drodata.rodata", sym->name) == 0)
325 special_local_sect = SECT_OFF_RODATA (objfile);
326 else
327 special_local_sect = -1;
328 if (special_local_sect >= 0)
329 {
330 /* Found a special local symbol. Allocate a
331 sectinfo, if needed, and fill it in. */
332 if (sectinfo == NULL)
333 {
334 int max_index;
335 size_t size;
336
337 max_index
338 = max (SECT_OFF_BSS (objfile),
339 max (SECT_OFF_DATA (objfile),
340 SECT_OFF_RODATA (objfile)));
341
342 /* max_index is the largest index we'll
343 use into this array, so we must
344 allocate max_index+1 elements for it.
345 However, 'struct stab_section_info'
346 already includes one element, so we
347 need to allocate max_index aadditional
348 elements. */
349 size = (sizeof (struct stab_section_info)
350 + (sizeof (CORE_ADDR)
351 * max_index));
352 sectinfo = (struct stab_section_info *)
353 xmalloc (size);
354 memset (sectinfo, 0, size);
355 sectinfo->num_sections = max_index;
356 if (filesym == NULL)
357 {
358 complaint (&symfile_complaints,
359 _("elf/stab section information %s without a preceding file symbol"),
360 sym->name);
361 }
362 else
363 {
364 sectinfo->filename =
365 (char *) filesym->name;
366 }
367 }
368 if (sectinfo->sections[special_local_sect] != 0)
369 complaint (&symfile_complaints,
370 _("duplicated elf/stab section information for %s"),
371 sectinfo->filename);
372 /* BFD symbols are section relative. */
373 symaddr = sym->value + sym->section->vma;
374 /* Relocate non-absolute symbols by the
375 section offset. */
376 if (sym->section != &bfd_abs_section)
377 symaddr += offset;
378 sectinfo->sections[special_local_sect] = symaddr;
379 /* The special local symbols don't go in the
380 minimal symbol table, so ignore this one. */
381 continue;
382 }
383 /* Not a special stabs-in-elf symbol, do regular
384 symbol processing. */
385 if (sym->section->flags & SEC_LOAD)
386 {
387 ms_type = mst_file_data;
388 }
389 else
390 {
391 ms_type = mst_file_bss;
392 }
393 }
394 else
395 {
396 ms_type = mst_unknown;
397 }
398 }
399 else
400 {
401 /* FIXME: Solaris2 shared libraries include lots of
402 odd "absolute" and "undefined" symbols, that play
403 hob with actions like finding what function the PC
404 is in. Ignore them if they aren't text, data, or bss. */
405 /* ms_type = mst_unknown; */
406 continue; /* Skip this symbol. */
407 }
408 msym = record_minimal_symbol
409 ((char *) sym->name, symaddr,
410 ms_type, sym->section, objfile);
411 if (msym)
412 {
413 /* Pass symbol size field in via BFD. FIXME!!! */
414 unsigned long size = ((elf_symbol_type *) sym)->internal_elf_sym.st_size;
415 MSYMBOL_SIZE(msym) = size;
416 }
417 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
418 if (msym != NULL)
419 msym->filename = filesymname;
420 #endif
421 ELF_MAKE_MSYMBOL_SPECIAL (sym, msym);
422 }
423 }
424 }
425
426 /* Scan and build partial symbols for a symbol file.
427 We have been initialized by a call to elf_symfile_init, which
428 currently does nothing.
429
430 SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
431 in each section. We simplify it down to a single offset for all
432 symbols. FIXME.
433
434 MAINLINE is true if we are reading the main symbol
435 table (as opposed to a shared lib or dynamically loaded file).
436
437 This function only does the minimum work necessary for letting the
438 user "name" things symbolically; it does not read the entire symtab.
439 Instead, it reads the external and static symbols and puts them in partial
440 symbol tables. When more extensive information is requested of a
441 file, the corresponding partial symbol table is mutated into a full
442 fledged symbol table by going back and reading the symbols
443 for real.
444
445 We look for sections with specific names, to tell us what debug
446 format to look for: FIXME!!!
447
448 dwarf_build_psymtabs() builds psymtabs for DWARF symbols;
449 elfstab_build_psymtabs() handles STABS symbols;
450 mdebug_build_psymtabs() handles ECOFF debugging information.
451
452 Note that ELF files have a "minimal" symbol table, which looks a lot
453 like a COFF symbol table, but has only the minimal information necessary
454 for linking. We process this also, and use the information to
455 build gdb's minimal symbol table. This gives us some minimal debugging
456 capability even for files compiled without -g. */
457
458 static void
459 elf_symfile_read (struct objfile *objfile, int mainline)
460 {
461 bfd *abfd = objfile->obfd;
462 struct elfinfo ei;
463 struct cleanup *back_to;
464 CORE_ADDR offset;
465 long symcount = 0, dynsymcount = 0, synthcount, storage_needed;
466 asymbol **symbol_table = NULL, **dyn_symbol_table = NULL;
467 asymbol *synthsyms;
468
469 init_minimal_symbol_collection ();
470 back_to = make_cleanup_discard_minimal_symbols ();
471
472 memset ((char *) &ei, 0, sizeof (ei));
473
474 /* Allocate struct to keep track of the symfile */
475 objfile->deprecated_sym_stab_info = (struct dbx_symfile_info *)
476 xmalloc (sizeof (struct dbx_symfile_info));
477 memset ((char *) objfile->deprecated_sym_stab_info, 0, sizeof (struct dbx_symfile_info));
478 make_cleanup (free_elfinfo, (void *) objfile);
479
480 /* Process the normal ELF symbol table first. This may write some
481 chain of info into the dbx_symfile_info in objfile->deprecated_sym_stab_info,
482 which can later be used by elfstab_offset_sections. */
483
484 storage_needed = bfd_get_symtab_upper_bound (objfile->obfd);
485 if (storage_needed < 0)
486 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd),
487 bfd_errmsg (bfd_get_error ()));
488
489 if (storage_needed > 0)
490 {
491 symbol_table = (asymbol **) xmalloc (storage_needed);
492 make_cleanup (xfree, symbol_table);
493 symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table);
494
495 if (symcount < 0)
496 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd),
497 bfd_errmsg (bfd_get_error ()));
498
499 elf_symtab_read (objfile, 0, symcount, symbol_table);
500 }
501
502 /* Add the dynamic symbols. */
503
504 storage_needed = bfd_get_dynamic_symtab_upper_bound (objfile->obfd);
505
506 if (storage_needed > 0)
507 {
508 dyn_symbol_table = (asymbol **) xmalloc (storage_needed);
509 make_cleanup (xfree, dyn_symbol_table);
510 dynsymcount = bfd_canonicalize_dynamic_symtab (objfile->obfd,
511 dyn_symbol_table);
512
513 if (dynsymcount < 0)
514 error (_("Can't read symbols from %s: %s"), bfd_get_filename (objfile->obfd),
515 bfd_errmsg (bfd_get_error ()));
516
517 elf_symtab_read (objfile, 1, dynsymcount, dyn_symbol_table);
518 }
519
520 /* Add synthetic symbols - for instance, names for any PLT entries. */
521
522 synthcount = bfd_get_synthetic_symtab (abfd, symcount, symbol_table,
523 dynsymcount, dyn_symbol_table,
524 &synthsyms);
525 if (synthcount > 0)
526 {
527 asymbol **synth_symbol_table;
528 long i;
529
530 make_cleanup (xfree, synthsyms);
531 synth_symbol_table = xmalloc (sizeof (asymbol *) * synthcount);
532 for (i = 0; i < synthcount; i++)
533 {
534 synth_symbol_table[i] = synthsyms + i;
535 /* Synthetic symbols are not, strictly speaking, either local
536 or global. But we can treat them as global symbols, since
537 they are effectively dynamic symbols. */
538 synth_symbol_table[i]->flags |= BSF_GLOBAL;
539 }
540 make_cleanup (xfree, synth_symbol_table);
541 elf_symtab_read (objfile, 0, synthcount, synth_symbol_table);
542 }
543
544 /* Install any minimal symbols that have been collected as the current
545 minimal symbols for this objfile. The debug readers below this point
546 should not generate new minimal symbols; if they do it's their
547 responsibility to install them. "mdebug" appears to be the only one
548 which will do this. */
549
550 install_minimal_symbols (objfile);
551 do_cleanups (back_to);
552
553 /* Now process debugging information, which is contained in
554 special ELF sections. */
555
556 /* If we are reinitializing, or if we have never loaded syms yet,
557 set table to empty. MAINLINE is cleared so that *_read_psymtab
558 functions do not all also re-initialize the psymbol table. */
559 if (mainline)
560 {
561 init_psymbol_list (objfile, 0);
562 mainline = 0;
563 }
564
565 /* We first have to find them... */
566 bfd_map_over_sections (abfd, elf_locate_sections, (void *) & ei);
567
568 /* ELF debugging information is inserted into the psymtab in the
569 order of least informative first - most informative last. Since
570 the psymtab table is searched `most recent insertion first' this
571 increases the probability that more detailed debug information
572 for a section is found.
573
574 For instance, an object file might contain both .mdebug (XCOFF)
575 and .debug_info (DWARF2) sections then .mdebug is inserted first
576 (searched last) and DWARF2 is inserted last (searched first). If
577 we don't do this then the XCOFF info is found first - for code in
578 an included file XCOFF info is useless. */
579
580 if (ei.mdebugsect)
581 {
582 const struct ecoff_debug_swap *swap;
583
584 /* .mdebug section, presumably holding ECOFF debugging
585 information. */
586 swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
587 if (swap)
588 elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect);
589 }
590 if (ei.stabsect)
591 {
592 asection *str_sect;
593
594 /* Stab sections have an associated string table that looks like
595 a separate section. */
596 str_sect = bfd_get_section_by_name (abfd, ".stabstr");
597
598 /* FIXME should probably warn about a stab section without a stabstr. */
599 if (str_sect)
600 elfstab_build_psymtabs (objfile,
601 mainline,
602 ei.stabsect,
603 str_sect->filepos,
604 bfd_section_size (abfd, str_sect));
605 }
606 if (dwarf2_has_info (objfile))
607 {
608 /* DWARF 2 sections */
609 dwarf2_build_psymtabs (objfile, mainline);
610 }
611 else if (ei.dboffset && ei.lnoffset)
612 {
613 /* DWARF sections */
614 dwarf_build_psymtabs (objfile,
615 mainline,
616 ei.dboffset, ei.dbsize,
617 ei.lnoffset, ei.lnsize);
618 }
619
620 /* FIXME: kettenis/20030504: This still needs to be integrated with
621 dwarf2read.c in a better way. */
622 dwarf2_build_frame_info (objfile);
623 }
624
625 /* This cleans up the objfile's deprecated_sym_stab_info pointer, and
626 the chain of stab_section_info's, that might be dangling from
627 it. */
628
629 static void
630 free_elfinfo (void *objp)
631 {
632 struct objfile *objfile = (struct objfile *) objp;
633 struct dbx_symfile_info *dbxinfo = objfile->deprecated_sym_stab_info;
634 struct stab_section_info *ssi, *nssi;
635
636 ssi = dbxinfo->stab_section_info;
637 while (ssi)
638 {
639 nssi = ssi->next;
640 xfree (ssi);
641 ssi = nssi;
642 }
643
644 dbxinfo->stab_section_info = 0; /* Just say No mo info about this. */
645 }
646
647
648 /* Initialize anything that needs initializing when a completely new symbol
649 file is specified (not just adding some symbols from another file, e.g. a
650 shared library).
651
652 We reinitialize buildsym, since we may be reading stabs from an ELF file. */
653
654 static void
655 elf_new_init (struct objfile *ignore)
656 {
657 stabsread_new_init ();
658 buildsym_new_init ();
659 }
660
661 /* Perform any local cleanups required when we are done with a particular
662 objfile. I.E, we are in the process of discarding all symbol information
663 for an objfile, freeing up all memory held for it, and unlinking the
664 objfile struct from the global list of known objfiles. */
665
666 static void
667 elf_symfile_finish (struct objfile *objfile)
668 {
669 if (objfile->deprecated_sym_stab_info != NULL)
670 {
671 xfree (objfile->deprecated_sym_stab_info);
672 }
673 }
674
675 /* ELF specific initialization routine for reading symbols.
676
677 It is passed a pointer to a struct sym_fns which contains, among other
678 things, the BFD for the file whose symbols are being read, and a slot for
679 a pointer to "private data" which we can fill with goodies.
680
681 For now at least, we have nothing in particular to do, so this function is
682 just a stub. */
683
684 static void
685 elf_symfile_init (struct objfile *objfile)
686 {
687 /* ELF objects may be reordered, so set OBJF_REORDERED. If we
688 find this causes a significant slowdown in gdb then we could
689 set it in the debug symbol readers only when necessary. */
690 objfile->flags |= OBJF_REORDERED;
691 }
692
693 /* When handling an ELF file that contains Sun STABS debug info,
694 some of the debug info is relative to the particular chunk of the
695 section that was generated in its individual .o file. E.g.
696 offsets to static variables are relative to the start of the data
697 segment *for that module before linking*. This information is
698 painfully squirreled away in the ELF symbol table as local symbols
699 with wierd names. Go get 'em when needed. */
700
701 void
702 elfstab_offset_sections (struct objfile *objfile, struct partial_symtab *pst)
703 {
704 char *filename = pst->filename;
705 struct dbx_symfile_info *dbx = objfile->deprecated_sym_stab_info;
706 struct stab_section_info *maybe = dbx->stab_section_info;
707 struct stab_section_info *questionable = 0;
708 int i;
709 char *p;
710
711 /* The ELF symbol info doesn't include path names, so strip the path
712 (if any) from the psymtab filename. */
713 while (0 != (p = strchr (filename, '/')))
714 filename = p + 1;
715
716 /* FIXME: This linear search could speed up significantly
717 if it was chained in the right order to match how we search it,
718 and if we unchained when we found a match. */
719 for (; maybe; maybe = maybe->next)
720 {
721 if (filename[0] == maybe->filename[0]
722 && strcmp (filename, maybe->filename) == 0)
723 {
724 /* We found a match. But there might be several source files
725 (from different directories) with the same name. */
726 if (0 == maybe->found)
727 break;
728 questionable = maybe; /* Might use it later. */
729 }
730 }
731
732 if (maybe == 0 && questionable != 0)
733 {
734 complaint (&symfile_complaints,
735 _("elf/stab section information questionable for %s"), filename);
736 maybe = questionable;
737 }
738
739 if (maybe)
740 {
741 /* Found it! Allocate a new psymtab struct, and fill it in. */
742 maybe->found++;
743 pst->section_offsets = (struct section_offsets *)
744 obstack_alloc (&objfile->objfile_obstack,
745 SIZEOF_N_SECTION_OFFSETS (objfile->num_sections));
746 for (i = 0; i < maybe->num_sections; i++)
747 (pst->section_offsets)->offsets[i] = maybe->sections[i];
748 return;
749 }
750
751 /* We were unable to find any offsets for this file. Complain. */
752 if (dbx->stab_section_info) /* If there *is* any info, */
753 complaint (&symfile_complaints,
754 _("elf/stab section information missing for %s"), filename);
755 }
756 \f
757 /* Register that we are able to handle ELF object file formats. */
758
759 static struct sym_fns elf_sym_fns =
760 {
761 bfd_target_elf_flavour,
762 elf_new_init, /* sym_new_init: init anything gbl to entire symtab */
763 elf_symfile_init, /* sym_init: read initial info, setup for sym_read() */
764 elf_symfile_read, /* sym_read: read a symbol file into symtab */
765 elf_symfile_finish, /* sym_finish: finished with file, cleanup */
766 default_symfile_offsets, /* sym_offsets: Translate ext. to int. relocation */
767 NULL /* next: pointer to next struct sym_fns */
768 };
769
770 void
771 _initialize_elfread (void)
772 {
773 add_symtab_fns (&elf_sym_fns);
774 }