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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 #include "defs.h"
  22 #include <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 struct section_offsets *
  47 nlm_symfile_offsets PARAMS ((struct objfile *, CORE_ADDR));
  48
  49 static void
  50 record_minimal_symbol PARAMS ((char *, CORE_ADDR, enum minimal_symbol_type,
  51                                struct objfile *));
  52
  53
  54 /* Initialize anything that needs initializing when a completely new symbol
  55    file is specified (not just adding some symbols from another file, e.g. a
  56    shared library).
  57
  58    We reinitialize buildsym, since gdb will be able to read stabs from an NLM
  59    file at some point in the near future.  */
  60
  61 static void
  62 nlm_new_init (ignore)
  63      struct objfile *ignore;
  64 {
  65   stabsread_new_init ();
  66   buildsym_new_init ();
  67 }
  68
  69
  70 /* NLM specific initialization routine for reading symbols.
  71
  72    It is passed a pointer to a struct sym_fns which contains, among other
  73    things, the BFD for the file whose symbols are being read, and a slot for
  74    a pointer to "private data" which we can fill with goodies.
  75
  76    For now at least, we have nothing in particular to do, so this function is
  77    just a stub. */
  78
  79 static void
  80 nlm_symfile_init (ignore)
  81      struct objfile *ignore;
  82 {
  83 }
  84
  85 static void
  86 record_minimal_symbol (name, address, ms_type, objfile)
  87      char *name;
  88      CORE_ADDR address;
  89      enum minimal_symbol_type ms_type;
  90      struct objfile *objfile;
  91 {
  92   name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
  93   prim_record_minimal_symbol (name, address, ms_type, objfile);
  94 }
  95
  96
  97 /*
  98
  99 LOCAL FUNCTION
 100
 101         nlm_symtab_read -- read the symbol table of an NLM file
 102
 103 SYNOPSIS
 104
 105         void nlm_symtab_read (bfd *abfd, CORE_ADDR addr,
 106                               struct objfile *objfile)
 107
 108 DESCRIPTION
 109
 110         Given an open bfd, a base address to relocate symbols to, and a
 111         flag that specifies whether or not this bfd is for an executable
 112         or not (may be shared library for example), add all the global
 113         function and data symbols to the minimal symbol table.
 114 */
 115
 116 static void
 117 nlm_symtab_read (abfd, addr, objfile)
 118      bfd *abfd;
 119      CORE_ADDR addr;
 120      struct objfile *objfile;
 121 {
 122   unsigned int storage_needed;
 123   asymbol *sym;
 124   asymbol **symbol_table;
 125   unsigned int number_of_symbols;
 126   unsigned int i;
 127   struct cleanup *back_to;
 128   CORE_ADDR symaddr;
 129   enum minimal_symbol_type ms_type;
 130
 131   storage_needed = get_symtab_upper_bound (abfd);
 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
 138       for (i = 0; i < number_of_symbols; i++)
 139         {
 140           sym = symbol_table[i];
 141           if (sym -> flags & BSF_GLOBAL)
 142             {
 143               /* Bfd symbols are section relative. */
 144               symaddr = sym -> value + sym -> section -> vma;
 145               /* Relocate all non-absolute symbols by base address.  */
 146               if (sym -> section != &bfd_abs_section)
 147                 {
 148                   symaddr += addr;
 149                 }
 150
 151               /* For non-absolute symbols, use the type of the section
 152                  they are relative to, to intuit text/data.  Bfd provides
 153                  no way of figuring this out for absolute symbols. */
 154               if (sym -> section -> flags & SEC_CODE)
 155                 {
 156                   ms_type = mst_text;
 157                 }
 158               else if (sym -> section -> flags & SEC_DATA)
 159                 {
 160                   ms_type = mst_data;
 161                 }
 162               else
 163                 {
 164                   ms_type = mst_unknown;
 165                 }
 166               record_minimal_symbol ((char *) sym -> name, symaddr, ms_type,
 167                                      objfile);
 168             }
 169         }
 170       do_cleanups (back_to);
 171     }
 172 }
 173
 174
 175 /* Scan and build partial symbols for a symbol file.
 176    We have been initialized by a call to nlm_symfile_init, which
 177    currently does nothing.
 178
 179    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 180    in each section.  We simplify it down to a single offset for all
 181    symbols.  FIXME.
 182
 183    MAINLINE is true if we are reading the main symbol
 184    table (as opposed to a shared lib or dynamically loaded file).
 185
 186    This function only does the minimum work necessary for letting the
 187    user "name" things symbolically; it does not read the entire symtab.
 188    Instead, it reads the external and static symbols and puts them in partial
 189    symbol tables.  When more extensive information is requested of a
 190    file, the corresponding partial symbol table is mutated into a full
 191    fledged symbol table by going back and reading the symbols
 192    for real.
 193
 194    Note that NLM files have two sets of information that is potentially
 195    useful for building gdb's minimal symbol table.  The first is a list
 196    of the publically exported symbols, and is currently used to build
 197    bfd's canonical symbol table.  The second is an optional native debugging
 198    format which contains additional symbols (and possibly duplicates of
 199    the publically exported symbols).  The optional native debugging format
 200    is not currently used. */
 201
 202 static void
 203 nlm_symfile_read (objfile, section_offsets, mainline)
 204      struct objfile *objfile;
 205      struct section_offsets *section_offsets;
 206      int mainline;
 207 {
 208   bfd *abfd = objfile -> obfd;
 209   struct cleanup *back_to;
 210   CORE_ADDR offset;
 211
 212   init_minimal_symbol_collection ();
 213   back_to = make_cleanup (discard_minimal_symbols, 0);
 214
 215   /* FIXME, should take a section_offsets param, not just an offset.  */
 216
 217   offset = ANOFFSET (section_offsets, 0);
 218
 219   /* Process the NLM export records, which become the bfd's canonical symbol
 220      table. */
 221
 222   nlm_symtab_read (abfd, offset, objfile);
 223
 224   /* FIXME:  We could locate and read the optional native debugging format
 225      here and add the symbols to the minimal symbol table. */
 226
 227   if (!have_partial_symbols ())
 228     {
 229       wrap_here ("");
 230       printf_filtered ("(no debugging symbols found)...");
 231       wrap_here ("");
 232     }
 233
 234   /* Install any minimal symbols that have been collected as the current
 235      minimal symbols for this objfile. */
 236
 237   install_minimal_symbols (objfile);
 238
 239   do_cleanups (back_to);
 240 }
 241
 242
 243 /* Perform any local cleanups required when we are done with a particular
 244    objfile.  I.E, we are in the process of discarding all symbol information
 245    for an objfile, freeing up all memory held for it, and unlinking the
 246    objfile struct from the global list of known objfiles. */
 247
 248 static void
 249 nlm_symfile_finish (objfile)
 250      struct objfile *objfile;
 251 {
 252   if (objfile -> sym_private != NULL)
 253     {
 254       mfree (objfile -> md, objfile -> sym_private);
 255     }
 256 }
 257
 258 /* NLM specific parsing routine for section offsets.
 259    FIXME:  This may or may not be necessary.  All the symbol readers seem
 260    to have similar code.  See if it can be generalized and moved elsewhere. */
 261
 262 static
 263 struct section_offsets *
 264 nlm_symfile_offsets (objfile, addr)
 265      struct objfile *objfile;
 266      CORE_ADDR addr;
 267 {
 268   struct section_offsets *section_offsets;
 269   int i;
 270
 271   objfile->num_sections = SECT_OFF_MAX;
 272   section_offsets = (struct section_offsets *)
 273     obstack_alloc (&objfile -> psymbol_obstack,
 274                    sizeof (struct section_offsets) +
 275                    sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
 276
 277   for (i = 0; i < SECT_OFF_MAX; i++)
 278     {
 279       ANOFFSET (section_offsets, i) = addr;
 280     }
 281
 282   return (section_offsets);
 283 }
 284
 285 \f
 286 /* Register that we are able to handle NLM file format. */
 287
 288 static struct sym_fns nlm_sym_fns =
 289 {
 290   bfd_target_nlm_flavour,
 291   nlm_new_init,         /* sym_new_init: init anything gbl to entire symtab */
 292   nlm_symfile_init,     /* sym_init: read initial info, setup for sym_read() */
 293   nlm_symfile_read,     /* sym_read: read a symbol file into symtab */
 294   nlm_symfile_finish,   /* sym_finish: finished with file, cleanup */
 295   nlm_symfile_offsets,  /* sym_offsets:  Translate ext. to int. relocation */
 296   NULL                  /* next: pointer to next struct sym_fns */
 297 };
 298
 299 void
 300 _initialize_nlmread ()
 301 {
 302   add_symtab_fns (&nlm_sym_fns);
 303 }