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