elfread.c revision 19370
1/* Read ELF (Executable and Linking Format) object files for GDB.
2   Copyright 1991, 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
3   Written by Fred Fish at Cygnus Support.
4
5This file is part of GDB.
6
7This program is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 2 of the License, or
10(at your option) any later version.
11
12This program is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with this program; if not, write to the Free Software
19Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
20
21#include "defs.h"
22#include "bfd.h"
23#include "gdb_string.h"
24#include "elf-bfd.h"
25#include "elf/mips.h"
26#include "symtab.h"
27#include "symfile.h"
28#include "objfiles.h"
29#include "buildsym.h"
30#include "stabsread.h"
31#include "gdb-stabs.h"
32#include "complaints.h"
33#include "demangle.h"
34
35/* The struct elfinfo is available only during ELF symbol table and
36   psymtab reading.  It is destroyed at the complation of psymtab-reading.
37   It's local to elf_symfile_read.  */
38
39struct elfinfo {
40  file_ptr dboffset;		/* Offset to dwarf debug section */
41  unsigned int dbsize;		/* Size of dwarf debug section */
42  file_ptr lnoffset;		/* Offset to dwarf line number section */
43  unsigned int lnsize;		/* Size of dwarf line number section */
44  asection *stabsect;		/* Section pointer for .stab section */
45  asection *stabindexsect;	/* Section pointer for .stab.index section */
46  asection *mdebugsect;		/* Section pointer for .mdebug section */
47};
48
49/* Various things we might complain about... */
50
51struct complaint section_info_complaint =
52  {"elf/stab section information %s without a preceding file symbol", 0, 0};
53
54struct complaint section_info_dup_complaint =
55  {"duplicated elf/stab section information for %s", 0, 0};
56
57struct complaint stab_info_mismatch_complaint =
58  {"elf/stab section information missing for %s", 0, 0};
59
60struct complaint stab_info_questionable_complaint =
61  {"elf/stab section information questionable for %s", 0, 0};
62
63static void
64elf_symfile_init PARAMS ((struct objfile *));
65
66static void
67elf_new_init PARAMS ((struct objfile *));
68
69static void
70elf_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
71
72static void
73elf_symfile_finish PARAMS ((struct objfile *));
74
75static void
76elf_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *, int));
77
78static void
79free_elfinfo PARAMS ((void *));
80
81static struct section_offsets *
82elf_symfile_offsets PARAMS ((struct objfile *, CORE_ADDR));
83
84static struct minimal_symbol *
85record_minimal_symbol_and_info PARAMS ((char *, CORE_ADDR,
86					enum minimal_symbol_type, char *,
87					struct objfile *));
88
89static void
90elf_locate_sections PARAMS ((bfd *, asection *, void *));
91
92/* We are called once per section from elf_symfile_read.  We
93   need to examine each section we are passed, check to see
94   if it is something we are interested in processing, and
95   if so, stash away some access information for the section.
96
97   For now we recognize the dwarf debug information sections and
98   line number sections from matching their section names.  The
99   ELF definition is no real help here since it has no direct
100   knowledge of DWARF (by design, so any debugging format can be
101   used).
102
103   We also recognize the ".stab" sections used by the Sun compilers
104   released with Solaris 2.
105
106   FIXME: The section names should not be hardwired strings (what
107   should they be?  I don't think most object file formats have enough
108   section flags to specify what kind of debug section it is
109   -kingdon).  */
110
111static void
112elf_locate_sections (ignore_abfd, sectp, eip)
113     bfd *ignore_abfd;
114     asection *sectp;
115     PTR eip;
116{
117  register struct elfinfo *ei;
118
119  ei = (struct elfinfo *) eip;
120  if (STREQ (sectp -> name, ".debug"))
121    {
122      ei -> dboffset = sectp -> filepos;
123      ei -> dbsize = bfd_get_section_size_before_reloc (sectp);
124    }
125  else if (STREQ (sectp -> name, ".line"))
126    {
127      ei -> lnoffset = sectp -> filepos;
128      ei -> lnsize = bfd_get_section_size_before_reloc (sectp);
129    }
130  else if (STREQ (sectp -> name, ".stab"))
131    {
132      ei -> stabsect = sectp;
133    }
134  else if (STREQ (sectp -> name, ".stab.index"))
135    {
136      ei -> stabindexsect = sectp;
137    }
138  else if (STREQ (sectp -> name, ".mdebug"))
139    {
140      ei -> mdebugsect = sectp;
141    }
142}
143
144#if 0	/* Currently unused */
145
146char *
147elf_interpreter (abfd)
148     bfd *abfd;
149{
150  sec_ptr interp_sec;
151  unsigned size;
152  char *interp = NULL;
153
154  interp_sec = bfd_get_section_by_name (abfd, ".interp");
155  if (interp_sec)
156    {
157      size = bfd_section_size (abfd, interp_sec);
158      interp = alloca (size);
159      if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr)0,
160				    size))
161	{
162	  interp = savestring (interp, size - 1);
163	}
164      else
165	{
166	  interp = NULL;
167	}
168    }
169  return (interp);
170}
171
172#endif
173
174static struct minimal_symbol *
175record_minimal_symbol_and_info (name, address, ms_type, info, objfile)
176     char *name;
177     CORE_ADDR address;
178     enum minimal_symbol_type ms_type;
179     char *info;		/* FIXME, is this really char *? */
180     struct objfile *objfile;
181{
182  int section;
183
184  /* Guess the section from the type.  This is likely to be wrong in
185     some cases.  */
186  switch (ms_type)
187    {
188    case mst_text:
189    case mst_file_text:
190      section = SECT_OFF_TEXT;
191#ifdef SMASH_TEXT_ADDRESS
192      SMASH_TEXT_ADDRESS (address);
193#endif
194      break;
195    case mst_data:
196    case mst_file_data:
197      section = SECT_OFF_DATA;
198      break;
199    case mst_bss:
200    case mst_file_bss:
201      section = SECT_OFF_BSS;
202      break;
203    default:
204      section = -1;
205      break;
206    }
207
208  name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
209  return prim_record_minimal_symbol_and_info
210    (name, address, ms_type, info, section, objfile);
211}
212
213/*
214
215LOCAL FUNCTION
216
217	elf_symtab_read -- read the symbol table of an ELF file
218
219SYNOPSIS
220
221	void elf_symtab_read (bfd *abfd, CORE_ADDR addr,
222			      struct objfile *objfile, int dynamic)
223
224DESCRIPTION
225
226	Given an open bfd, a base address to relocate symbols to, and a
227	flag that specifies whether or not this bfd is for an executable
228	or not (may be shared library for example), add all the global
229	function and data symbols to the minimal symbol table.
230
231	In stabs-in-ELF, as implemented by Sun, there are some local symbols
232	defined in the ELF symbol table, which can be used to locate
233	the beginnings of sections from each ".o" file that was linked to
234	form the executable objfile.  We gather any such info and record it
235	in data structures hung off the objfile's private data.
236
237*/
238
239static void
240elf_symtab_read (abfd, addr, objfile, dynamic)
241     bfd *abfd;
242     CORE_ADDR addr;
243     struct objfile *objfile;
244     int dynamic;
245{
246  long storage_needed;
247  asymbol *sym;
248  asymbol **symbol_table;
249  long number_of_symbols;
250  long i;
251  int index;
252  struct cleanup *back_to;
253  CORE_ADDR symaddr;
254  enum minimal_symbol_type ms_type;
255  /* If sectinfo is nonNULL, it contains section info that should end up
256     filed in the objfile.  */
257  struct stab_section_info *sectinfo = NULL;
258  /* If filesym is nonzero, it points to a file symbol, but we haven't
259     seen any section info for it yet.  */
260  asymbol *filesym = 0;
261#ifdef SOFUN_ADDRESS_MAYBE_MISSING
262  /* Name of filesym, as saved on the symbol_obstack.  */
263  char *filesymname = obsavestring ("", 0, &objfile->symbol_obstack);
264#endif
265  struct dbx_symfile_info *dbx = (struct dbx_symfile_info *)
266				 objfile->sym_stab_info;
267  unsigned long size;
268  int stripped = (bfd_get_symcount (abfd) == 0);
269
270  if (dynamic)
271    {
272      storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
273
274      /* Nothing to be done if there is no dynamic symtab.  */
275      if (storage_needed < 0)
276	return;
277    }
278  else
279    {
280      storage_needed = bfd_get_symtab_upper_bound (abfd);
281      if (storage_needed < 0)
282	error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
283	       bfd_errmsg (bfd_get_error ()));
284    }
285  if (storage_needed > 0)
286    {
287      symbol_table = (asymbol **) xmalloc (storage_needed);
288      back_to = make_cleanup (free, symbol_table);
289      if (dynamic)
290        number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd,
291							     symbol_table);
292      else
293        number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
294      if (number_of_symbols < 0)
295	error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
296	       bfd_errmsg (bfd_get_error ()));
297      for (i = 0; i < number_of_symbols; i++)
298	{
299	  sym = symbol_table[i];
300	  if (sym -> name == NULL || *sym -> name == '\0')
301	    {
302	      /* Skip names that don't exist (shouldn't happen), or names
303		 that are null strings (may happen). */
304	      continue;
305	    }
306
307	  if (dynamic
308	      && sym -> section == &bfd_und_section
309	      && (sym -> flags & BSF_FUNCTION))
310	    {
311	      struct minimal_symbol *msym;
312
313	      /* Symbol is a reference to a function defined in
314		 a shared library.
315		 If its value is non zero then it is usually the address
316		 of the corresponding entry in the procedure linkage table,
317		 relative to the base address.
318		 If its value is zero then the dynamic linker has to resolve
319		 the symbol. We are unable to find any meaningful address
320		 for this symbol in the executable file, so we skip it.  */
321	      symaddr = sym -> value;
322	      if (symaddr == 0)
323		continue;
324	      symaddr += addr;
325	      msym = record_minimal_symbol_and_info
326		((char *) sym -> name, symaddr,
327		mst_solib_trampoline, NULL, objfile);
328#ifdef SOFUN_ADDRESS_MAYBE_MISSING
329	      if (msym != NULL)
330		msym->filename = filesymname;
331#endif
332	      continue;
333	    }
334
335	  /* If it is a nonstripped executable, do not enter dynamic
336	     symbols, as the dynamic symbol table is usually a subset
337	     of the main symbol table.  */
338	  if (dynamic && !stripped)
339	    continue;
340	  if (sym -> flags & BSF_FILE)
341	    {
342	      /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
343		 Chain any old one onto the objfile; remember new sym.  */
344	      if (sectinfo != NULL)
345		{
346		  sectinfo -> next = dbx -> stab_section_info;
347		  dbx -> stab_section_info = sectinfo;
348		  sectinfo = NULL;
349		}
350	      filesym = sym;
351#ifdef SOFUN_ADDRESS_MAYBE_MISSING
352	      filesymname =
353		obsavestring ((char *)filesym->name, strlen (filesym->name),
354			      &objfile->symbol_obstack);
355#endif
356	    }
357	  else if (sym -> flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
358	    {
359	      struct minimal_symbol *msym;
360
361	      /* Select global/local/weak symbols.  Note that bfd puts abs
362		 symbols in their own section, so all symbols we are
363		 interested in will have a section. */
364	      /* Bfd symbols are section relative. */
365	      symaddr = sym -> value + sym -> section -> vma;
366	      /* Relocate all non-absolute symbols by base address.  */
367	      if (sym -> section != &bfd_abs_section)
368		{
369		  symaddr += addr;
370		}
371	      /* For non-absolute symbols, use the type of the section
372		 they are relative to, to intuit text/data.  Bfd provides
373		 no way of figuring this out for absolute symbols. */
374	      if (sym -> section == &bfd_abs_section)
375		{
376		  /* This is a hack to get the minimal symbol type
377		     right for Irix 5, which has absolute adresses
378		     with special section indices for dynamic symbols. */
379		  unsigned short shndx =
380		    ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
381
382		  switch (shndx)
383		    {
384		    case SHN_MIPS_TEXT:
385		      ms_type = mst_text;
386		      break;
387		    case SHN_MIPS_DATA:
388		      ms_type = mst_data;
389		      break;
390		    case SHN_MIPS_ACOMMON:
391		      ms_type = mst_bss;
392		      break;
393		    default:
394		      ms_type = mst_abs;
395		    }
396		}
397	      else if (sym -> section -> flags & SEC_CODE)
398		{
399		  if (sym -> flags & BSF_GLOBAL)
400		    {
401		      ms_type = mst_text;
402		    }
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 it.
408		       The assembler should be skipping these (to keep
409		       executables small), but apparently with gcc on the
410		       delta m88k SVR4, it loses.  So to have us check too
411		       should be harmless (but I encourage people to fix this
412		       in the assembler instead of adding checks here).  */
413		    continue;
414		  else
415		    {
416		      ms_type = mst_file_text;
417		    }
418		}
419	      else if (sym -> section -> flags & SEC_ALLOC)
420		{
421		  if (sym -> flags & BSF_GLOBAL)
422		    {
423		      if (sym -> section -> flags & SEC_LOAD)
424			{
425			  ms_type = mst_data;
426			}
427		      else
428			{
429			  ms_type = mst_bss;
430			}
431		    }
432		  else if (sym -> flags & BSF_LOCAL)
433		    {
434		      /* Named Local variable in a Data section.  Check its
435			 name for stabs-in-elf.  The STREQ macro checks the
436			 first character inline, so we only actually do a
437			 strcmp function call on names that start with 'B'
438			 or 'D' */
439		      index = SECT_OFF_MAX;
440		      if (STREQ ("Bbss.bss", sym -> name))
441			{
442			  index = SECT_OFF_BSS;
443			}
444		      else if (STREQ ("Ddata.data", sym -> name))
445			{
446			  index = SECT_OFF_DATA;
447			}
448		      else if (STREQ ("Drodata.rodata", sym -> name))
449			{
450			  index = SECT_OFF_RODATA;
451			}
452		      if (index != SECT_OFF_MAX)
453			{
454			  /* Found a special local symbol.  Allocate a
455			     sectinfo, if needed, and fill it in.  */
456			  if (sectinfo == NULL)
457			    {
458			      sectinfo = (struct stab_section_info *)
459				xmmalloc (objfile -> md, sizeof (*sectinfo));
460			      memset ((PTR) sectinfo, 0, sizeof (*sectinfo));
461			      if (filesym == NULL)
462				{
463				  complain (&section_info_complaint,
464					    sym -> name);
465				}
466			      else
467				{
468				  sectinfo -> filename =
469				    (char *) filesym -> name;
470				}
471			    }
472			  if (sectinfo -> sections[index] != 0)
473			    {
474			      complain (&section_info_dup_complaint,
475					sectinfo -> filename);
476			    }
477			  /* Bfd symbols are section relative. */
478			  symaddr = sym -> value + sym -> section -> vma;
479			  /* Relocate non-absolute symbols by base address.  */
480			  if (sym -> section != &bfd_abs_section)
481			    {
482			      symaddr += addr;
483			    }
484			  sectinfo -> sections[index] = symaddr;
485			  /* The special local symbols don't go in the
486			     minimal symbol table, so ignore this one. */
487			  continue;
488			}
489		      /* Not a special stabs-in-elf symbol, do regular
490			 symbol processing. */
491		      if (sym -> section -> flags & SEC_LOAD)
492			{
493			  ms_type = mst_file_data;
494			}
495		      else
496			{
497			  ms_type = mst_file_bss;
498			}
499		    }
500		  else
501		    {
502		      ms_type = mst_unknown;
503		    }
504		}
505	      else
506		{
507		  /* FIXME:  Solaris2 shared libraries include lots of
508		     odd "absolute" and "undefined" symbols, that play
509		     hob with actions like finding what function the PC
510		     is in.  Ignore them if they aren't text, data, or bss.  */
511		  /* ms_type = mst_unknown; */
512		  continue;		/* Skip this symbol. */
513		}
514	      /* Pass symbol size field in via BFD.  FIXME!!!  */
515	      size = ((elf_symbol_type *) sym) -> internal_elf_sym.st_size;
516	      msym = record_minimal_symbol_and_info
517		((char *) sym -> name, symaddr,
518		 ms_type, (PTR) size, objfile);
519#ifdef SOFUN_ADDRESS_MAYBE_MISSING
520	      if (msym != NULL)
521		msym->filename = filesymname;
522#endif
523	    }
524	}
525      do_cleanups (back_to);
526    }
527}
528
529/* Scan and build partial symbols for a symbol file.
530   We have been initialized by a call to elf_symfile_init, which
531   currently does nothing.
532
533   SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
534   in each section.  We simplify it down to a single offset for all
535   symbols.  FIXME.
536
537   MAINLINE is true if we are reading the main symbol
538   table (as opposed to a shared lib or dynamically loaded file).
539
540   This function only does the minimum work necessary for letting the
541   user "name" things symbolically; it does not read the entire symtab.
542   Instead, it reads the external and static symbols and puts them in partial
543   symbol tables.  When more extensive information is requested of a
544   file, the corresponding partial symbol table is mutated into a full
545   fledged symbol table by going back and reading the symbols
546   for real.
547
548   We look for sections with specific names, to tell us what debug
549   format to look for:  FIXME!!!
550
551   dwarf_build_psymtabs() builds psymtabs for DWARF symbols;
552   elfstab_build_psymtabs() handles STABS symbols;
553   mdebug_build_psymtabs() handles ECOFF debugging information.
554
555   Note that ELF files have a "minimal" symbol table, which looks a lot
556   like a COFF symbol table, but has only the minimal information necessary
557   for linking.  We process this also, and use the information to
558   build gdb's minimal symbol table.  This gives us some minimal debugging
559   capability even for files compiled without -g.  */
560
561static void
562elf_symfile_read (objfile, section_offsets, mainline)
563     struct objfile *objfile;
564     struct section_offsets *section_offsets;
565     int mainline;
566{
567  bfd *abfd = objfile->obfd;
568  struct elfinfo ei;
569  struct cleanup *back_to;
570  CORE_ADDR offset;
571
572  init_minimal_symbol_collection ();
573  back_to = make_cleanup (discard_minimal_symbols, 0);
574
575  memset ((char *) &ei, 0, sizeof (ei));
576
577  /* Allocate struct to keep track of the symfile */
578  objfile->sym_stab_info = (PTR)
579    xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info));
580  memset ((char *) objfile->sym_stab_info, 0, sizeof (struct dbx_symfile_info));
581  make_cleanup (free_elfinfo, (PTR) objfile);
582
583  /* Process the normal ELF symbol table first.  This may write some
584     chain of info into the dbx_symfile_info in objfile->sym_stab_info,
585     which can later be used by elfstab_offset_sections.  */
586
587  /* FIXME, should take a section_offsets param, not just an offset.  */
588  offset = ANOFFSET (section_offsets, 0);
589  elf_symtab_read (abfd, offset, objfile, 0);
590
591  /* Add the dynamic symbols.  */
592
593  elf_symtab_read (abfd, offset, objfile, 1);
594
595  /* Now process debugging information, which is contained in
596     special ELF sections.  We first have to find them... */
597
598  bfd_map_over_sections (abfd, elf_locate_sections, (PTR) &ei);
599  if (ei.dboffset && ei.lnoffset)
600    {
601      /* DWARF sections */
602      dwarf_build_psymtabs (objfile,
603			    section_offsets, mainline,
604			    ei.dboffset, ei.dbsize,
605			    ei.lnoffset, ei.lnsize);
606    }
607  if (ei.stabsect)
608    {
609      asection *str_sect;
610
611      /* Stab sections have an associated string table that looks like
612	 a separate section.  */
613      str_sect = bfd_get_section_by_name (abfd, ".stabstr");
614
615      /* FIXME should probably warn about a stab section without a stabstr.  */
616      if (str_sect)
617	elfstab_build_psymtabs (objfile,
618				section_offsets,
619				mainline,
620				ei.stabsect->filepos,
621				bfd_section_size (abfd, ei.stabsect),
622				str_sect->filepos,
623				bfd_section_size (abfd, str_sect));
624    }
625  if (ei.mdebugsect)
626    {
627      const struct ecoff_debug_swap *swap;
628
629      /* .mdebug section, presumably holding ECOFF debugging
630	 information.  */
631      swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
632      if (swap)
633	elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect,
634				  section_offsets);
635    }
636
637  /* Install any minimal symbols that have been collected as the current
638     minimal symbols for this objfile. */
639
640  install_minimal_symbols (objfile);
641
642  do_cleanups (back_to);
643}
644
645/* This cleans up the objfile's sym_stab_info pointer, and the chain of
646   stab_section_info's, that might be dangling from it.  */
647
648static void
649free_elfinfo (objp)
650     PTR objp;
651{
652  struct objfile *objfile = (struct objfile *)objp;
653  struct dbx_symfile_info *dbxinfo = (struct dbx_symfile_info *)
654				     objfile->sym_stab_info;
655  struct stab_section_info *ssi, *nssi;
656
657  ssi = dbxinfo->stab_section_info;
658  while (ssi)
659    {
660      nssi = ssi->next;
661      mfree (objfile->md, ssi);
662      ssi = nssi;
663    }
664
665  dbxinfo->stab_section_info = 0;	/* Just say No mo info about this.  */
666}
667
668
669/* Initialize anything that needs initializing when a completely new symbol
670   file is specified (not just adding some symbols from another file, e.g. a
671   shared library).
672
673   We reinitialize buildsym, since we may be reading stabs from an ELF file.  */
674
675static void
676elf_new_init (ignore)
677     struct objfile *ignore;
678{
679  stabsread_new_init ();
680  buildsym_new_init ();
681}
682
683/* Perform any local cleanups required when we are done with a particular
684   objfile.  I.E, we are in the process of discarding all symbol information
685   for an objfile, freeing up all memory held for it, and unlinking the
686   objfile struct from the global list of known objfiles. */
687
688static void
689elf_symfile_finish (objfile)
690     struct objfile *objfile;
691{
692  if (objfile -> sym_stab_info != NULL)
693    {
694      mfree (objfile -> md, objfile -> sym_stab_info);
695    }
696}
697
698/* ELF specific initialization routine for reading symbols.
699
700   It is passed a pointer to a struct sym_fns which contains, among other
701   things, the BFD for the file whose symbols are being read, and a slot for
702   a pointer to "private data" which we can fill with goodies.
703
704   For now at least, we have nothing in particular to do, so this function is
705   just a stub. */
706
707static void
708elf_symfile_init (objfile)
709     struct objfile *objfile;
710{
711  /* ELF objects may be reordered, so set OBJF_REORDERED.  If we
712     find this causes a significant slowdown in gdb then we could
713     set it in the debug symbol readers only when necessary.  */
714  objfile->flags |= OBJF_REORDERED;
715}
716
717/* ELF specific parsing routine for section offsets.
718
719   Plain and simple for now.  */
720
721static
722struct section_offsets *
723elf_symfile_offsets (objfile, addr)
724     struct objfile *objfile;
725     CORE_ADDR addr;
726{
727  struct section_offsets *section_offsets;
728  int i;
729
730  objfile->num_sections = SECT_OFF_MAX;
731  section_offsets = (struct section_offsets *)
732    obstack_alloc (&objfile -> psymbol_obstack,
733		   sizeof (struct section_offsets)
734		   + sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
735
736  for (i = 0; i < SECT_OFF_MAX; i++)
737    ANOFFSET (section_offsets, i) = addr;
738
739  return section_offsets;
740}
741
742/* When handling an ELF file that contains Sun STABS debug info,
743   some of the debug info is relative to the particular chunk of the
744   section that was generated in its individual .o file.  E.g.
745   offsets to static variables are relative to the start of the data
746   segment *for that module before linking*.  This information is
747   painfully squirreled away in the ELF symbol table as local symbols
748   with wierd names.  Go get 'em when needed.  */
749
750void
751elfstab_offset_sections (objfile, pst)
752     struct objfile *objfile;
753     struct partial_symtab *pst;
754{
755  char *filename = pst->filename;
756  struct dbx_symfile_info *dbx = (struct dbx_symfile_info *)
757				 objfile->sym_stab_info;
758  struct stab_section_info *maybe = dbx->stab_section_info;
759  struct stab_section_info *questionable = 0;
760  int i;
761  char *p;
762
763  /* The ELF symbol info doesn't include path names, so strip the path
764     (if any) from the psymtab filename.  */
765  while (0 != (p = strchr (filename, '/')))
766    filename = p+1;
767
768  /* FIXME:  This linear search could speed up significantly
769     if it was chained in the right order to match how we search it,
770     and if we unchained when we found a match. */
771  for (; maybe; maybe = maybe->next)
772    {
773      if (filename[0] == maybe->filename[0]
774	  && STREQ (filename, maybe->filename))
775	{
776	  /* We found a match.  But there might be several source files
777	     (from different directories) with the same name.  */
778	  if (0 == maybe->found)
779	    break;
780	  questionable = maybe;		/* Might use it later.  */
781	}
782    }
783
784  if (maybe == 0 && questionable != 0)
785    {
786      complain (&stab_info_questionable_complaint, filename);
787      maybe = questionable;
788    }
789
790  if (maybe)
791    {
792      /* Found it!  Allocate a new psymtab struct, and fill it in.  */
793      maybe->found++;
794      pst->section_offsets = (struct section_offsets *)
795	obstack_alloc (&objfile -> psymbol_obstack,
796		       sizeof (struct section_offsets) +
797	       sizeof (pst->section_offsets->offsets) * (SECT_OFF_MAX-1));
798
799      for (i = 0; i < SECT_OFF_MAX; i++)
800	ANOFFSET (pst->section_offsets, i) = maybe->sections[i];
801      return;
802    }
803
804  /* We were unable to find any offsets for this file.  Complain.  */
805  if (dbx->stab_section_info)		/* If there *is* any info, */
806    complain (&stab_info_mismatch_complaint, filename);
807}
808
809/* Register that we are able to handle ELF object file formats.  */
810
811static struct sym_fns elf_sym_fns =
812{
813  bfd_target_elf_flavour,
814  elf_new_init,		/* sym_new_init: init anything gbl to entire symtab */
815  elf_symfile_init,	/* sym_init: read initial info, setup for sym_read() */
816  elf_symfile_read,	/* sym_read: read a symbol file into symtab */
817  elf_symfile_finish,	/* sym_finish: finished with file, cleanup */
818  elf_symfile_offsets,	/* sym_offsets:  Translate ext. to int. relocation */
819  NULL			/* next: pointer to next struct sym_fns */
820};
821
822void
823_initialize_elfread ()
824{
825  add_symtab_fns (&elf_sym_fns);
826}
827