gdb/nlmread.c

   1 /* Read NLM (NetWare Loadable Module) format executable files for GDB.
   2    Copyright 1993, 1994 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 static void
  47 record_minimal_symbol PARAMS ((char *, CORE_ADDR, enum minimal_symbol_type,
  48                                struct objfile *));
  49
  50
  51 /* Initialize anything that needs initializing when a completely new symbol
  52    file is specified (not just adding some symbols from another file, e.g. a
  53    shared library).
  54
  55    We reinitialize buildsym, since gdb will be able to read stabs from an NLM
  56    file at some point in the near future.  */
  57
  58 static void
  59 nlm_new_init (ignore)
  60      struct objfile *ignore;
  61 {
  62   stabsread_new_init ();
  63   buildsym_new_init ();
  64 }
  65
  66
  67 /* NLM specific initialization routine for reading symbols.
  68
  69    It is passed a pointer to a struct sym_fns which contains, among other
  70    things, the BFD for the file whose symbols are being read, and a slot for
  71    a pointer to "private data" which we can fill with goodies.
  72
  73    For now at least, we have nothing in particular to do, so this function is
  74    just a stub. */
  75
  76 static void
  77 nlm_symfile_init (ignore)
  78      struct objfile *ignore;
  79 {
  80 }
  81
  82 static void
  83 record_minimal_symbol (name, address, ms_type, objfile)
  84      char *name;
  85      CORE_ADDR address;
  86      enum minimal_symbol_type ms_type;
  87      struct objfile *objfile;
  88 {
  89   name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
  90   prim_record_minimal_symbol (name, address, ms_type, objfile);
  91 }
  92
  93
  94 /*
  95
  96 LOCAL FUNCTION
  97
  98         nlm_symtab_read -- read the symbol table of an NLM file
  99
 100 SYNOPSIS
 101
 102         void nlm_symtab_read (bfd *abfd, CORE_ADDR addr,
 103                               struct objfile *objfile)
 104
 105 DESCRIPTION
 106
 107         Given an open bfd, a base address to relocate symbols to, and a
 108         flag that specifies whether or not this bfd is for an executable
 109         or not (may be shared library for example), add all the global
 110         function and data symbols to the minimal symbol table.
 111 */
 112
 113 static void
 114 nlm_symtab_read (abfd, addr, objfile)
 115      bfd *abfd;
 116      CORE_ADDR addr;
 117      struct objfile *objfile;
 118 {
 119   long storage_needed;
 120   asymbol *sym;
 121   asymbol **symbol_table;
 122   long number_of_symbols;
 123   long i;
 124   struct cleanup *back_to;
 125   CORE_ADDR symaddr;
 126   enum minimal_symbol_type ms_type;
 127
 128   storage_needed = bfd_get_symtab_upper_bound (abfd);
 129   if (storage_needed < 0)
 130     error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 131            bfd_errmsg (bfd_get_error ()));
 132   if (storage_needed > 0)
 133     {
 134       symbol_table = (asymbol **) xmalloc (storage_needed);
 135       back_to = make_cleanup (free, symbol_table);
 136       number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 137       if (number_of_symbols < 0)
 138         error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 139                bfd_errmsg (bfd_get_error ()));
 140
 141       for (i = 0; i < number_of_symbols; i++)
 142         {
 143           sym = symbol_table[i];
 144           if (/*sym -> flags & BSF_GLOBAL*/ 1)
 145             {
 146               /* Bfd symbols are section relative. */
 147               symaddr = sym -> value + sym -> section -> vma;
 148               /* Relocate all non-absolute symbols by base address.  */
 149               if (sym -> section != &bfd_abs_section)
 150                 symaddr += addr;
 151
 152               /* For non-absolute symbols, use the type of the section
 153                  they are relative to, to intuit text/data.  BFD provides
 154                  no way of figuring this out for absolute symbols. */
 155               if (sym -> section -> flags & SEC_CODE)
 156                 ms_type = mst_text;
 157               else if (sym -> section -> flags & SEC_DATA)
 158                 ms_type = mst_data;
 159               else
 160                 ms_type = mst_unknown;
 161
 162               record_minimal_symbol ((char *) sym -> name, symaddr, ms_type,
 163                                      objfile);
 164             }
 165         }
 166       do_cleanups (back_to);
 167     }
 168 }
 169
 170
 171 /* Scan and build partial symbols for a symbol file.
 172    We have been initialized by a call to nlm_symfile_init, which
 173    currently does nothing.
 174
 175    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 176    in each section.  We simplify it down to a single offset for all
 177    symbols.  FIXME.
 178
 179    MAINLINE is true if we are reading the main symbol
 180    table (as opposed to a shared lib or dynamically loaded file).
 181
 182    This function only does the minimum work necessary for letting the
 183    user "name" things symbolically; it does not read the entire symtab.
 184    Instead, it reads the external and static symbols and puts them in partial
 185    symbol tables.  When more extensive information is requested of a
 186    file, the corresponding partial symbol table is mutated into a full
 187    fledged symbol table by going back and reading the symbols
 188    for real.
 189
 190    Note that NLM files have two sets of information that is potentially
 191    useful for building gdb's minimal symbol table.  The first is a list
 192    of the publically exported symbols, and is currently used to build
 193    bfd's canonical symbol table.  The second is an optional native debugging
 194    format which contains additional symbols (and possibly duplicates of
 195    the publically exported symbols).  The optional native debugging format
 196    is not currently used. */
 197
 198 static void
 199 nlm_symfile_read (objfile, section_offsets, mainline)
 200      struct objfile *objfile;
 201      struct section_offsets *section_offsets;
 202      int mainline;
 203 {
 204   bfd *abfd = objfile -> obfd;
 205   struct cleanup *back_to;
 206   CORE_ADDR offset;
 207   struct symbol *mainsym;
 208
 209   init_minimal_symbol_collection ();
 210   back_to = make_cleanup (discard_minimal_symbols, 0);
 211
 212   /* FIXME, should take a section_offsets param, not just an offset.  */
 213
 214   offset = ANOFFSET (section_offsets, 0);
 215
 216   /* Process the NLM export records, which become the bfd's canonical symbol
 217      table. */
 218
 219   nlm_symtab_read (abfd, offset, objfile);
 220
 221   stabsect_build_psymtabs (objfile, section_offsets, mainline, ".stab",
 222                            ".stabstr", ".text");
 223
 224   mainsym = lookup_symbol ("main", NULL, VAR_NAMESPACE, NULL, NULL);
 225
 226   if (mainsym
 227       && SYMBOL_CLASS(mainsym) == LOC_BLOCK)
 228     {
 229       objfile->ei.main_func_lowpc = BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
 230       objfile->ei.main_func_highpc = BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
 231     }
 232
 233   /* FIXME:  We could locate and read the optional native debugging format
 234      here and add the symbols to the minimal symbol table. */
 235
 236   /* Install any minimal symbols that have been collected as the current
 237      minimal symbols for this objfile. */
 238
 239   install_minimal_symbols (objfile);
 240
 241   do_cleanups (back_to);
 242 }
 243
 244
 245 /* Perform any local cleanups required when we are done with a particular
 246    objfile.  I.E, we are in the process of discarding all symbol information
 247    for an objfile, freeing up all memory held for it, and unlinking the
 248    objfile struct from the global list of known objfiles. */
 249
 250 static void
 251 nlm_symfile_finish (objfile)
 252      struct objfile *objfile;
 253 {
 254   if (objfile -> sym_private != NULL)
 255     {
 256       mfree (objfile -> md, objfile -> sym_private);
 257     }
 258 }
 259
 260 /* Register that we are able to handle NLM file format. */
 261
 262 static struct sym_fns nlm_sym_fns =
 263 {
 264   bfd_target_nlm_flavour,
 265   nlm_new_init,         /* sym_new_init: init anything gbl to entire symtab */
 266   nlm_symfile_init,     /* sym_init: read initial info, setup for sym_read() */
 267   nlm_symfile_read,     /* sym_read: read a symbol file into symtab */
 268   nlm_symfile_finish,   /* sym_finish: finished with file, cleanup */
 269   default_symfile_offsets,
 270                         /* sym_offsets:  Translate ext. to int. relocation */
 271   NULL                  /* next: pointer to next struct sym_fns */
 272 };
 273
 274 void
 275 _initialize_nlmread ()
 276 {
 277   add_symtab_fns (&nlm_sym_fns);
 278 }