gdb/nlmread.c

   1 /* Read NLM (NetWare Loadable Module) format executable files for GDB.
   2    Copyright 1993, 1994, 1998 Free Software Foundation, Inc.
   3    Written by Fred Fish at Cygnus Support (fnf@cygnus.com).
   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 "gdb_string.h"
  23 #include "bfd.h"
  24 #include "symtab.h"
  25 #include "symfile.h"
  26 #include "objfiles.h"
  27 #include "gdb-stabs.h"
  28 #include "buildsym.h"
  29 #include "stabsread.h"
  30
  31 static void
  32 nlm_new_init PARAMS ((struct objfile *));
  33
  34 static void
  35 nlm_symfile_init PARAMS ((struct objfile *));
  36
  37 static void
  38 nlm_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
  39
  40 static void
  41 nlm_symfile_finish PARAMS ((struct objfile *));
  42
  43 static void
  44 nlm_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *));
  45
  46 /* Initialize anything that needs initializing when a completely new symbol
  47    file is specified (not just adding some symbols from another file, e.g. a
  48    shared library).
  49
  50    We reinitialize buildsym, since gdb will be able to read stabs from an NLM
  51    file at some point in the near future.  */
  52
  53 static void
  54 nlm_new_init (ignore)
  55      struct objfile *ignore;
  56 {
  57   stabsread_new_init ();
  58   buildsym_new_init ();
  59 }
  60
  61
  62 /* NLM specific initialization routine for reading symbols.
  63
  64    It is passed a pointer to a struct sym_fns which contains, among other
  65    things, the BFD for the file whose symbols are being read, and a slot for
  66    a pointer to "private data" which we can fill with goodies.
  67
  68    For now at least, we have nothing in particular to do, so this function is
  69    just a stub. */
  70
  71 static void
  72 nlm_symfile_init (ignore)
  73      struct objfile *ignore;
  74 {
  75 }
  76
  77 /*
  78
  79 LOCAL FUNCTION
  80
  81         nlm_symtab_read -- read the symbol table of an NLM file
  82
  83 SYNOPSIS
  84
  85         void nlm_symtab_read (bfd *abfd, CORE_ADDR addr,
  86                               struct objfile *objfile)
  87
  88 DESCRIPTION
  89
  90         Given an open bfd, a base address to relocate symbols to, and a
  91         flag that specifies whether or not this bfd is for an executable
  92         or not (may be shared library for example), add all the global
  93         function and data symbols to the minimal symbol table.
  94 */
  95
  96 static void
  97 nlm_symtab_read (abfd, addr, objfile)
  98      bfd *abfd;
  99      CORE_ADDR addr;
 100      struct objfile *objfile;
 101 {
 102   long storage_needed;
 103   asymbol *sym;
 104   asymbol **symbol_table;
 105   long number_of_symbols;
 106   long i;
 107   struct cleanup *back_to;
 108   CORE_ADDR symaddr;
 109   enum minimal_symbol_type ms_type;
 110
 111   storage_needed = bfd_get_symtab_upper_bound (abfd);
 112   if (storage_needed < 0)
 113     error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 114            bfd_errmsg (bfd_get_error ()));
 115   if (storage_needed > 0)
 116     {
 117       symbol_table = (asymbol **) xmalloc (storage_needed);
 118       back_to = make_cleanup (free, symbol_table);
 119       number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 120       if (number_of_symbols < 0)
 121         error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 122                bfd_errmsg (bfd_get_error ()));
 123
 124       for (i = 0; i < number_of_symbols; i++)
 125         {
 126           sym = symbol_table[i];
 127           if (/*sym -> flags & BSF_GLOBAL*/ 1)
 128             {
 129               /* Bfd symbols are section relative. */
 130               symaddr = sym -> value + sym -> section -> vma;
 131               /* Relocate all non-absolute symbols by base address.  */
 132               if (sym -> section != &bfd_abs_section)
 133                 symaddr += addr;
 134
 135               /* For non-absolute symbols, use the type of the section
 136                  they are relative to, to intuit text/data.  BFD provides
 137                  no way of figuring this out for absolute symbols. */
 138               if (sym -> section -> flags & SEC_CODE)
 139                 ms_type = mst_text;
 140               else if (sym -> section -> flags & SEC_DATA)
 141                 ms_type = mst_data;
 142               else
 143                 ms_type = mst_unknown;
 144
 145               prim_record_minimal_symbol (sym -> name, symaddr, ms_type,
 146                                           objfile);
 147             }
 148         }
 149       do_cleanups (back_to);
 150     }
 151 }
 152
 153
 154 /* Scan and build partial symbols for a symbol file.
 155    We have been initialized by a call to nlm_symfile_init, which
 156    currently does nothing.
 157
 158    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 159    in each section.  We simplify it down to a single offset for all
 160    symbols.  FIXME.
 161
 162    MAINLINE is true if we are reading the main symbol
 163    table (as opposed to a shared lib or dynamically loaded file).
 164
 165    This function only does the minimum work necessary for letting the
 166    user "name" things symbolically; it does not read the entire symtab.
 167    Instead, it reads the external and static symbols and puts them in partial
 168    symbol tables.  When more extensive information is requested of a
 169    file, the corresponding partial symbol table is mutated into a full
 170    fledged symbol table by going back and reading the symbols
 171    for real.
 172
 173    Note that NLM files have two sets of information that is potentially
 174    useful for building gdb's minimal symbol table.  The first is a list
 175    of the publically exported symbols, and is currently used to build
 176    bfd's canonical symbol table.  The second is an optional native debugging
 177    format which contains additional symbols (and possibly duplicates of
 178    the publically exported symbols).  The optional native debugging format
 179    is not currently used. */
 180
 181 static void
 182 nlm_symfile_read (objfile, section_offsets, mainline)
 183      struct objfile *objfile;
 184      struct section_offsets *section_offsets;
 185      int mainline;
 186 {
 187   bfd *abfd = objfile -> obfd;
 188   struct cleanup *back_to;
 189   CORE_ADDR offset;
 190   struct symbol *mainsym;
 191
 192   init_minimal_symbol_collection ();
 193   back_to = make_cleanup ((make_cleanup_func) discard_minimal_symbols, 0);
 194
 195   /* FIXME, should take a section_offsets param, not just an offset.  */
 196
 197   offset = ANOFFSET (section_offsets, 0);
 198
 199   /* Process the NLM export records, which become the bfd's canonical symbol
 200      table. */
 201
 202   nlm_symtab_read (abfd, offset, objfile);
 203
 204   stabsect_build_psymtabs (objfile, section_offsets, mainline, ".stab",
 205                            ".stabstr", ".text");
 206
 207   mainsym = lookup_symbol ("main", NULL, VAR_NAMESPACE, NULL, NULL);
 208
 209   if (mainsym
 210       && SYMBOL_CLASS(mainsym) == LOC_BLOCK)
 211     {
 212       objfile->ei.main_func_lowpc = BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
 213       objfile->ei.main_func_highpc = BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
 214     }
 215
 216   /* FIXME:  We could locate and read the optional native debugging format
 217      here and add the symbols to the minimal symbol table. */
 218
 219   /* Install any minimal symbols that have been collected as the current
 220      minimal symbols for this objfile. */
 221
 222   install_minimal_symbols (objfile);
 223
 224   do_cleanups (back_to);
 225 }
 226
 227
 228 /* Perform any local cleanups required when we are done with a particular
 229    objfile.  I.E, we are in the process of discarding all symbol information
 230    for an objfile, freeing up all memory held for it, and unlinking the
 231    objfile struct from the global list of known objfiles. */
 232
 233 static void
 234 nlm_symfile_finish (objfile)
 235      struct objfile *objfile;
 236 {
 237   if (objfile -> sym_private != NULL)
 238     {
 239       mfree (objfile -> md, objfile -> sym_private);
 240     }
 241 }
 242
 243 /* Register that we are able to handle NLM file format. */
 244
 245 static struct sym_fns nlm_sym_fns =
 246 {
 247   bfd_target_nlm_flavour,
 248   nlm_new_init,         /* sym_new_init: init anything gbl to entire symtab */
 249   nlm_symfile_init,     /* sym_init: read initial info, setup for sym_read() */
 250   nlm_symfile_read,     /* sym_read: read a symbol file into symtab */
 251   nlm_symfile_finish,   /* sym_finish: finished with file, cleanup */
 252   default_symfile_offsets,
 253                         /* sym_offsets:  Translate ext. to int. relocation */
 254   NULL                  /* next: pointer to next struct sym_fns */
 255 };
 256
 257 void
 258 _initialize_nlmread ()
 259 {
 260   add_symtab_fns (&nlm_sym_fns);
 261 }