gdb/elfread.c

   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
   5 This file is part of GDB.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, 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
  39 struct 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
  51 struct complaint section_info_complaint =
  52   {"elf/stab section information %s without a preceding file symbol", 0, 0};
  53
  54 struct complaint section_info_dup_complaint =
  55   {"duplicated elf/stab section information for %s", 0, 0};
  56
  57 struct complaint stab_info_mismatch_complaint =
  58   {"elf/stab section information missing for %s", 0, 0};
  59
  60 struct complaint stab_info_questionable_complaint =
  61   {"elf/stab section information questionable for %s", 0, 0};
  62
  63 static void
  64 elf_symfile_init PARAMS ((struct objfile *));
  65
  66 static void
  67 elf_new_init PARAMS ((struct objfile *));
  68
  69 static void
  70 elf_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
  71
  72 static void
  73 elf_symfile_finish PARAMS ((struct objfile *));
  74
  75 static void
  76 elf_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *, int));
  77
  78 static void
  79 free_elfinfo PARAMS ((void *));
  80
  81 static struct minimal_symbol *
  82 record_minimal_symbol_and_info PARAMS ((char *, CORE_ADDR,
  83                                         enum minimal_symbol_type, char *,
  84                                         asection *bfd_section,
  85                                         struct objfile *));
  86
  87 static void
  88 elf_locate_sections PARAMS ((bfd *, asection *, void *));
  89
  90 /* We are called once per section from elf_symfile_read.  We
  91    need to examine each section we are passed, check to see
  92    if it is something we are interested in processing, and
  93    if so, stash away some access information for the section.
  94
  95    For now we recognize the dwarf debug information sections and
  96    line number sections from matching their section names.  The
  97    ELF definition is no real help here since it has no direct
  98    knowledge of DWARF (by design, so any debugging format can be
  99    used).
 100
 101    We also recognize the ".stab" sections used by the Sun compilers
 102    released with Solaris 2.
 103
 104    FIXME: The section names should not be hardwired strings (what
 105    should they be?  I don't think most object file formats have enough
 106    section flags to specify what kind of debug section it is
 107    -kingdon).  */
 108
 109 static void
 110 elf_locate_sections (ignore_abfd, sectp, eip)
 111      bfd *ignore_abfd;
 112      asection *sectp;
 113      PTR eip;
 114 {
 115   register struct elfinfo *ei;
 116
 117   ei = (struct elfinfo *) eip;
 118   if (STREQ (sectp -> name, ".debug"))
 119     {
 120       ei -> dboffset = sectp -> filepos;
 121       ei -> dbsize = bfd_get_section_size_before_reloc (sectp);
 122     }
 123   else if (STREQ (sectp -> name, ".line"))
 124     {
 125       ei -> lnoffset = sectp -> filepos;
 126       ei -> lnsize = bfd_get_section_size_before_reloc (sectp);
 127     }
 128   else if (STREQ (sectp -> name, ".stab"))
 129     {
 130       ei -> stabsect = sectp;
 131     }
 132   else if (STREQ (sectp -> name, ".stab.index"))
 133     {
 134       ei -> stabindexsect = sectp;
 135     }
 136   else if (STREQ (sectp -> name, ".mdebug"))
 137     {
 138       ei -> mdebugsect = sectp;
 139     }
 140 }
 141
 142 #if 0   /* Currently unused */
 143
 144 char *
 145 elf_interpreter (abfd)
 146      bfd *abfd;
 147 {
 148   sec_ptr interp_sec;
 149   unsigned size;
 150   char *interp = NULL;
 151
 152   interp_sec = bfd_get_section_by_name (abfd, ".interp");
 153   if (interp_sec)
 154     {
 155       size = bfd_section_size (abfd, interp_sec);
 156       interp = alloca (size);
 157       if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr)0,
 158                                     size))
 159         {
 160           interp = savestring (interp, size - 1);
 161         }
 162       else
 163         {
 164           interp = NULL;
 165         }
 166     }
 167   return (interp);
 168 }
 169
 170 #endif
 171
 172 static struct minimal_symbol *
 173 record_minimal_symbol_and_info (name, address, ms_type, info, bfd_section,
 174                                 objfile)
 175      char *name;
 176      CORE_ADDR address;
 177      enum minimal_symbol_type ms_type;
 178      char *info;                /* FIXME, is this really char *? */
 179      asection *bfd_section;
 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   return prim_record_minimal_symbol_and_info
 209     (name, address, ms_type, info, section, bfd_section, objfile);
 210 }
 211
 212 /*
 213
 214 LOCAL FUNCTION
 215
 216         elf_symtab_read -- read the symbol table of an ELF file
 217
 218 SYNOPSIS
 219
 220         void elf_symtab_read (bfd *abfd, CORE_ADDR addr,
 221                               struct objfile *objfile, int dynamic)
 222
 223 DESCRIPTION
 224
 225         Given an open bfd, a base address to relocate symbols to, and a
 226         flag that specifies whether or not this bfd is for an executable
 227         or not (may be shared library for example), add all the global
 228         function and data symbols to the minimal symbol table.
 229
 230         In stabs-in-ELF, as implemented by Sun, there are some local symbols
 231         defined in the ELF symbol table, which can be used to locate
 232         the beginnings of sections from each ".o" file that was linked to
 233         form the executable objfile.  We gather any such info and record it
 234         in data structures hung off the objfile's private data.
 235
 236 */
 237
 238 static void
 239 elf_symtab_read (abfd, addr, objfile, dynamic)
 240      bfd *abfd;
 241      CORE_ADDR addr;
 242      struct objfile *objfile;
 243      int dynamic;
 244 {
 245   long storage_needed;
 246   asymbol *sym;
 247   asymbol **symbol_table;
 248   long number_of_symbols;
 249   long i;
 250   int index;
 251   struct cleanup *back_to;
 252   CORE_ADDR symaddr;
 253   enum minimal_symbol_type ms_type;
 254   /* If sectinfo is nonNULL, it contains section info that should end up
 255      filed in the objfile.  */
 256   struct stab_section_info *sectinfo = NULL;
 257   /* If filesym is nonzero, it points to a file symbol, but we haven't
 258      seen any section info for it yet.  */
 259   asymbol *filesym = 0;
 260 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
 261   /* Name of filesym, as saved on the symbol_obstack.  */
 262   char *filesymname = obsavestring ("", 0, &objfile->symbol_obstack);
 263 #endif
 264   struct dbx_symfile_info *dbx = objfile->sym_stab_info;
 265   unsigned long size;
 266   int stripped = (bfd_get_symcount (abfd) == 0);
 267
 268   if (dynamic)
 269     {
 270       storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
 271
 272       /* Nothing to be done if there is no dynamic symtab.  */
 273       if (storage_needed < 0)
 274         return;
 275     }
 276   else
 277     {
 278       storage_needed = bfd_get_symtab_upper_bound (abfd);
 279       if (storage_needed < 0)
 280         error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 281                bfd_errmsg (bfd_get_error ()));
 282     }
 283   if (storage_needed > 0)
 284     {
 285       symbol_table = (asymbol **) xmalloc (storage_needed);
 286       back_to = make_cleanup (free, symbol_table);
 287       if (dynamic)
 288         number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd,
 289                                                              symbol_table);
 290       else
 291         number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 292       if (number_of_symbols < 0)
 293         error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 294                bfd_errmsg (bfd_get_error ()));
 295       for (i = 0; i < number_of_symbols; i++)
 296         {
 297           sym = symbol_table[i];
 298           if (sym -> name == NULL || *sym -> name == '\0')
 299             {
 300               /* Skip names that don't exist (shouldn't happen), or names
 301                  that are null strings (may happen). */
 302               continue;
 303             }
 304
 305           if (dynamic
 306               && sym -> section == &bfd_und_section
 307               && (sym -> flags & BSF_FUNCTION))
 308             {
 309               struct minimal_symbol *msym;
 310
 311               /* Symbol is a reference to a function defined in
 312                  a shared library.
 313                  If its value is non zero then it is usually the address
 314                  of the corresponding entry in the procedure linkage table,
 315                  relative to the base address.
 316                  If its value is zero then the dynamic linker has to resolve
 317                  the symbol. We are unable to find any meaningful address
 318                  for this symbol in the executable file, so we skip it.  */
 319               symaddr = sym -> value;
 320               if (symaddr == 0)
 321                 continue;
 322               symaddr += addr;
 323               msym = record_minimal_symbol_and_info
 324                 ((char *) sym -> name, symaddr,
 325                 mst_solib_trampoline, NULL, sym -> section, objfile);
 326 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
 327               if (msym != NULL)
 328                 msym->filename = filesymname;
 329 #endif
 330               continue;
 331             }
 332
 333           /* If it is a nonstripped executable, do not enter dynamic
 334              symbols, as the dynamic symbol table is usually a subset
 335              of the main symbol table.  */
 336           if (dynamic && !stripped)
 337             continue;
 338           if (sym -> flags & BSF_FILE)
 339             {
 340               /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
 341                  Chain any old one onto the objfile; remember new sym.  */
 342               if (sectinfo != NULL)
 343                 {
 344                   sectinfo -> next = dbx -> stab_section_info;
 345                   dbx -> stab_section_info = sectinfo;
 346                   sectinfo = NULL;
 347                 }
 348               filesym = sym;
 349 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
 350               filesymname =
 351                 obsavestring ((char *)filesym->name, strlen (filesym->name),
 352                               &objfile->symbol_obstack);
 353 #endif
 354             }
 355           else if (sym -> flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
 356             {
 357               struct minimal_symbol *msym;
 358
 359               /* Select global/local/weak symbols.  Note that bfd puts abs
 360                  symbols in their own section, so all symbols we are
 361                  interested in will have a section. */
 362               /* Bfd symbols are section relative. */
 363               symaddr = sym -> value + sym -> section -> vma;
 364               /* Relocate all non-absolute symbols by base address.  */
 365               if (sym -> section != &bfd_abs_section)
 366                 {
 367                   symaddr += addr;
 368                 }
 369               /* For non-absolute symbols, use the type of the section
 370                  they are relative to, to intuit text/data.  Bfd provides
 371                  no way of figuring this out for absolute symbols. */
 372               if (sym -> section == &bfd_abs_section)
 373                 {
 374                   /* This is a hack to get the minimal symbol type
 375                      right for Irix 5, which has absolute adresses
 376                      with special section indices for dynamic symbols. */
 377                   unsigned short shndx =
 378                     ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
 379
 380                   switch (shndx)
 381                     {
 382                     case SHN_MIPS_TEXT:
 383                       ms_type = mst_text;
 384                       break;
 385                     case SHN_MIPS_DATA:
 386                       ms_type = mst_data;
 387                       break;
 388                     case SHN_MIPS_ACOMMON:
 389                       ms_type = mst_bss;
 390                       break;
 391                     default:
 392                       ms_type = mst_abs;
 393                     }
 394
 395                   /* If it is an Irix dynamic symbol, skip section name
 396                      symbols, relocate all others. */
 397                   if (ms_type != mst_abs)
 398                     {
 399                       if (sym->name[0] == '.')
 400                         continue;
 401                       symaddr += addr;
 402                     }
 403                 }
 404               else if (sym -> section -> flags & SEC_CODE)
 405                 {
 406                   if (sym -> flags & BSF_GLOBAL)
 407                     {
 408                       ms_type = mst_text;
 409                     }
 410                   else if ((sym->name[0] == '.' && sym->name[1] == 'L')
 411                            || ((sym -> flags & BSF_LOCAL)
 412                                && sym->name[0] == '$'
 413                                && sym->name[1] == 'L'))
 414                     /* Looks like a compiler-generated label.  Skip it.
 415                        The assembler should be skipping these (to keep
 416                        executables small), but apparently with gcc on the
 417                        delta m88k SVR4, it loses.  So to have us check too
 418                        should be harmless (but I encourage people to fix this
 419                        in the assembler instead of adding checks here).  */
 420                     continue;
 421 #ifdef HARRIS_TARGET
 422                   else if (sym->name[0] == '.' && sym->name[1] == '.')
 423                     {
 424                       /* Looks like a Harris compiler generated label for the
 425                          purpose of marking instructions that are relevant to
 426                          DWARF dies.  The assembler can't get rid of these
 427                          because they are relocatable addresses that the
 428                          linker needs to resolve. */
 429                       continue;
 430                     }
 431 #endif
 432                   else
 433                     {
 434                       ms_type = mst_file_text;
 435                     }
 436                 }
 437               else if (sym -> section -> flags & SEC_ALLOC)
 438                 {
 439                   if (sym -> flags & BSF_GLOBAL)
 440                     {
 441                       if (sym -> section -> flags & SEC_LOAD)
 442                         {
 443                           ms_type = mst_data;
 444                         }
 445                       else
 446                         {
 447                           ms_type = mst_bss;
 448                         }
 449                     }
 450                   else if (sym -> flags & BSF_LOCAL)
 451                     {
 452                       /* Named Local variable in a Data section.  Check its
 453                          name for stabs-in-elf.  The STREQ macro checks the
 454                          first character inline, so we only actually do a
 455                          strcmp function call on names that start with 'B'
 456                          or 'D' */
 457                       index = SECT_OFF_MAX;
 458                       if (STREQ ("Bbss.bss", sym -> name))
 459                         {
 460                           index = SECT_OFF_BSS;
 461                         }
 462                       else if (STREQ ("Ddata.data", sym -> name))
 463                         {
 464                           index = SECT_OFF_DATA;
 465                         }
 466                       else if (STREQ ("Drodata.rodata", sym -> name))
 467                         {
 468                           index = SECT_OFF_RODATA;
 469                         }
 470                       if (index != SECT_OFF_MAX)
 471                         {
 472                           /* Found a special local symbol.  Allocate a
 473                              sectinfo, if needed, and fill it in.  */
 474                           if (sectinfo == NULL)
 475                             {
 476                               sectinfo = (struct stab_section_info *)
 477                                 xmmalloc (objfile -> md, sizeof (*sectinfo));
 478                               memset ((PTR) sectinfo, 0, sizeof (*sectinfo));
 479                               if (filesym == NULL)
 480                                 {
 481                                   complain (&section_info_complaint,
 482                                             sym -> name);
 483                                 }
 484                               else
 485                                 {
 486                                   sectinfo -> filename =
 487                                     (char *) filesym -> name;
 488                                 }
 489                             }
 490                           if (sectinfo -> sections[index] != 0)
 491                             {
 492                               complain (&section_info_dup_complaint,
 493                                         sectinfo -> filename);
 494                             }
 495                           /* Bfd symbols are section relative. */
 496                           symaddr = sym -> value + sym -> section -> vma;
 497                           /* Relocate non-absolute symbols by base address.  */
 498                           if (sym -> section != &bfd_abs_section)
 499                             {
 500                               symaddr += addr;
 501                             }
 502                           sectinfo -> sections[index] = symaddr;
 503                           /* The special local symbols don't go in the
 504                              minimal symbol table, so ignore this one. */
 505                           continue;
 506                         }
 507                       /* Not a special stabs-in-elf symbol, do regular
 508                          symbol processing. */
 509                       if (sym -> section -> flags & SEC_LOAD)
 510                         {
 511                           ms_type = mst_file_data;
 512                         }
 513                       else
 514                         {
 515                           ms_type = mst_file_bss;
 516                         }
 517                     }
 518                   else
 519                     {
 520                       ms_type = mst_unknown;
 521                     }
 522                 }
 523               else
 524                 {
 525                   /* FIXME:  Solaris2 shared libraries include lots of
 526                      odd "absolute" and "undefined" symbols, that play
 527                      hob with actions like finding what function the PC
 528                      is in.  Ignore them if they aren't text, data, or bss.  */
 529                   /* ms_type = mst_unknown; */
 530                   continue;             /* Skip this symbol. */
 531                 }
 532               /* Pass symbol size field in via BFD.  FIXME!!!  */
 533               size = ((elf_symbol_type *) sym) -> internal_elf_sym.st_size;
 534               msym = record_minimal_symbol_and_info
 535                 ((char *) sym -> name, symaddr,
 536                  ms_type, (PTR) size, sym -> section, objfile);
 537 #ifdef SOFUN_ADDRESS_MAYBE_MISSING
 538               if (msym != NULL)
 539                 msym->filename = filesymname;
 540 #endif
 541             }
 542         }
 543       do_cleanups (back_to);
 544     }
 545 }
 546
 547 /* Scan and build partial symbols for a symbol file.
 548    We have been initialized by a call to elf_symfile_init, which
 549    currently does nothing.
 550
 551    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 552    in each section.  We simplify it down to a single offset for all
 553    symbols.  FIXME.
 554
 555    MAINLINE is true if we are reading the main symbol
 556    table (as opposed to a shared lib or dynamically loaded file).
 557
 558    This function only does the minimum work necessary for letting the
 559    user "name" things symbolically; it does not read the entire symtab.
 560    Instead, it reads the external and static symbols and puts them in partial
 561    symbol tables.  When more extensive information is requested of a
 562    file, the corresponding partial symbol table is mutated into a full
 563    fledged symbol table by going back and reading the symbols
 564    for real.
 565
 566    We look for sections with specific names, to tell us what debug
 567    format to look for:  FIXME!!!
 568
 569    dwarf_build_psymtabs() builds psymtabs for DWARF symbols;
 570    elfstab_build_psymtabs() handles STABS symbols;
 571    mdebug_build_psymtabs() handles ECOFF debugging information.
 572
 573    Note that ELF files have a "minimal" symbol table, which looks a lot
 574    like a COFF symbol table, but has only the minimal information necessary
 575    for linking.  We process this also, and use the information to
 576    build gdb's minimal symbol table.  This gives us some minimal debugging
 577    capability even for files compiled without -g.  */
 578
 579 static void
 580 elf_symfile_read (objfile, section_offsets, mainline)
 581      struct objfile *objfile;
 582      struct section_offsets *section_offsets;
 583      int mainline;
 584 {
 585   bfd *abfd = objfile->obfd;
 586   struct elfinfo ei;
 587   struct cleanup *back_to;
 588   CORE_ADDR offset;
 589
 590   init_minimal_symbol_collection ();
 591   back_to = make_cleanup (discard_minimal_symbols, 0);
 592
 593   memset ((char *) &ei, 0, sizeof (ei));
 594
 595   /* Allocate struct to keep track of the symfile */
 596   objfile->sym_stab_info = (PTR)
 597     xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info));
 598   memset ((char *) objfile->sym_stab_info, 0, sizeof (struct dbx_symfile_info));
 599   make_cleanup (free_elfinfo, (PTR) objfile);
 600
 601   /* Process the normal ELF symbol table first.  This may write some
 602      chain of info into the dbx_symfile_info in objfile->sym_stab_info,
 603      which can later be used by elfstab_offset_sections.  */
 604
 605   /* FIXME, should take a section_offsets param, not just an offset.  */
 606   offset = ANOFFSET (section_offsets, 0);
 607   elf_symtab_read (abfd, offset, objfile, 0);
 608
 609   /* Add the dynamic symbols.  */
 610
 611   elf_symtab_read (abfd, offset, objfile, 1);
 612
 613   /* Now process debugging information, which is contained in
 614      special ELF sections.  We first have to find them... */
 615
 616   bfd_map_over_sections (abfd, elf_locate_sections, (PTR) &ei);
 617   if (dwarf2_has_info (abfd))
 618     {
 619       /* DWARF 2 sections */
 620       dwarf2_build_psymtabs (objfile, section_offsets, mainline);
 621     }
 622   else if (ei.dboffset && ei.lnoffset)
 623     {
 624       /* DWARF sections */
 625       dwarf_build_psymtabs (objfile,
 626                             section_offsets, mainline,
 627                             ei.dboffset, ei.dbsize,
 628                             ei.lnoffset, ei.lnsize);
 629     }
 630   if (ei.stabsect)
 631     {
 632       asection *str_sect;
 633
 634       /* Stab sections have an associated string table that looks like
 635          a separate section.  */
 636       str_sect = bfd_get_section_by_name (abfd, ".stabstr");
 637
 638       /* FIXME should probably warn about a stab section without a stabstr.  */
 639       if (str_sect)
 640         elfstab_build_psymtabs (objfile,
 641                                 section_offsets,
 642                                 mainline,
 643                                 ei.stabsect->filepos,
 644                                 bfd_section_size (abfd, ei.stabsect),
 645                                 str_sect->filepos,
 646                                 bfd_section_size (abfd, str_sect));
 647     }
 648   if (ei.mdebugsect)
 649     {
 650       const struct ecoff_debug_swap *swap;
 651
 652       /* .mdebug section, presumably holding ECOFF debugging
 653          information.  */
 654       swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
 655       if (swap)
 656         elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect,
 657                                   section_offsets);
 658     }
 659
 660   /* Install any minimal symbols that have been collected as the current
 661      minimal symbols for this objfile. */
 662
 663   install_minimal_symbols (objfile);
 664
 665   do_cleanups (back_to);
 666 }
 667
 668 /* This cleans up the objfile's sym_stab_info pointer, and the chain of
 669    stab_section_info's, that might be dangling from it.  */
 670
 671 static void
 672 free_elfinfo (objp)
 673      PTR objp;
 674 {
 675   struct objfile *objfile = (struct objfile *)objp;
 676   struct dbx_symfile_info *dbxinfo = objfile->sym_stab_info;
 677   struct stab_section_info *ssi, *nssi;
 678
 679   ssi = dbxinfo->stab_section_info;
 680   while (ssi)
 681     {
 682       nssi = ssi->next;
 683       mfree (objfile->md, ssi);
 684       ssi = nssi;
 685     }
 686
 687   dbxinfo->stab_section_info = 0;       /* Just say No mo info about this.  */
 688 }
 689
 690
 691 /* Initialize anything that needs initializing when a completely new symbol
 692    file is specified (not just adding some symbols from another file, e.g. a
 693    shared library).
 694
 695    We reinitialize buildsym, since we may be reading stabs from an ELF file.  */
 696
 697 static void
 698 elf_new_init (ignore)
 699      struct objfile *ignore;
 700 {
 701   stabsread_new_init ();
 702   buildsym_new_init ();
 703 }
 704
 705 /* Perform any local cleanups required when we are done with a particular
 706    objfile.  I.E, we are in the process of discarding all symbol information
 707    for an objfile, freeing up all memory held for it, and unlinking the
 708    objfile struct from the global list of known objfiles. */
 709
 710 static void
 711 elf_symfile_finish (objfile)
 712      struct objfile *objfile;
 713 {
 714   if (objfile -> sym_stab_info != NULL)
 715     {
 716       mfree (objfile -> md, objfile -> sym_stab_info);
 717     }
 718 }
 719
 720 /* ELF specific initialization routine for reading symbols.
 721
 722    It is passed a pointer to a struct sym_fns which contains, among other
 723    things, the BFD for the file whose symbols are being read, and a slot for
 724    a pointer to "private data" which we can fill with goodies.
 725
 726    For now at least, we have nothing in particular to do, so this function is
 727    just a stub. */
 728
 729 static void
 730 elf_symfile_init (objfile)
 731      struct objfile *objfile;
 732 {
 733   /* ELF objects may be reordered, so set OBJF_REORDERED.  If we
 734      find this causes a significant slowdown in gdb then we could
 735      set it in the debug symbol readers only when necessary.  */
 736   objfile->flags |= OBJF_REORDERED;
 737 }
 738
 739 /* When handling an ELF file that contains Sun STABS debug info,
 740    some of the debug info is relative to the particular chunk of the
 741    section that was generated in its individual .o file.  E.g.
 742    offsets to static variables are relative to the start of the data
 743    segment *for that module before linking*.  This information is
 744    painfully squirreled away in the ELF symbol table as local symbols
 745    with wierd names.  Go get 'em when needed.  */
 746
 747 void
 748 elfstab_offset_sections (objfile, pst)
 749      struct objfile *objfile;
 750      struct partial_symtab *pst;
 751 {
 752   char *filename = pst->filename;
 753   struct dbx_symfile_info *dbx = objfile->sym_stab_info;
 754   struct stab_section_info *maybe = dbx->stab_section_info;
 755   struct stab_section_info *questionable = 0;
 756   int i;
 757   char *p;
 758
 759   /* The ELF symbol info doesn't include path names, so strip the path
 760      (if any) from the psymtab filename.  */
 761   while (0 != (p = strchr (filename, '/')))
 762     filename = p+1;
 763
 764   /* FIXME:  This linear search could speed up significantly
 765      if it was chained in the right order to match how we search it,
 766      and if we unchained when we found a match. */
 767   for (; maybe; maybe = maybe->next)
 768     {
 769       if (filename[0] == maybe->filename[0]
 770           && STREQ (filename, maybe->filename))
 771         {
 772           /* We found a match.  But there might be several source files
 773              (from different directories) with the same name.  */
 774           if (0 == maybe->found)
 775             break;
 776           questionable = maybe;         /* Might use it later.  */
 777         }
 778     }
 779
 780   if (maybe == 0 && questionable != 0)
 781     {
 782       complain (&stab_info_questionable_complaint, filename);
 783       maybe = questionable;
 784     }
 785
 786   if (maybe)
 787     {
 788       /* Found it!  Allocate a new psymtab struct, and fill it in.  */
 789       maybe->found++;
 790       pst->section_offsets = (struct section_offsets *)
 791         obstack_alloc (&objfile -> psymbol_obstack,
 792                        sizeof (struct section_offsets) +
 793                sizeof (pst->section_offsets->offsets) * (SECT_OFF_MAX-1));
 794
 795       for (i = 0; i < SECT_OFF_MAX; i++)
 796         ANOFFSET (pst->section_offsets, i) = maybe->sections[i];
 797       return;
 798     }
 799
 800   /* We were unable to find any offsets for this file.  Complain.  */
 801   if (dbx->stab_section_info)           /* If there *is* any info, */
 802     complain (&stab_info_mismatch_complaint, filename);
 803 }
 804 \f
 805 /* Register that we are able to handle ELF object file formats.  */
 806
 807 static struct sym_fns elf_sym_fns =
 808 {
 809   bfd_target_elf_flavour,
 810   elf_new_init,         /* sym_new_init: init anything gbl to entire symtab */
 811   elf_symfile_init,     /* sym_init: read initial info, setup for sym_read() */
 812   elf_symfile_read,     /* sym_read: read a symbol file into symtab */
 813   elf_symfile_finish,   /* sym_finish: finished with file, cleanup */
 814   default_symfile_offsets,
 815                         /* sym_offsets:  Translate ext. to int. relocation */
 816   NULL                  /* next: pointer to next struct sym_fns */
 817 };
 818
 819 void
 820 _initialize_elfread ()
 821 {
 822   add_symtab_fns (&elf_sym_fns);
 823 }