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 "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 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   long storage_needed;
 123   asymbol *sym;
 124   asymbol **symbol_table;
 125   long number_of_symbols;
 126   long i;
 127   struct cleanup *back_to;
 128   CORE_ADDR symaddr;
 129   enum minimal_symbol_type ms_type;
 130
 131   storage_needed = bfd_get_symtab_upper_bound (abfd);
 132   if (storage_needed < 0)
 133     error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 134            bfd_errmsg (bfd_get_error ()));
 135   if (storage_needed > 0)
 136     {
 137       symbol_table = (asymbol **) xmalloc (storage_needed);
 138       back_to = make_cleanup (free, symbol_table);
 139       number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 140       if (number_of_symbols < 0)
 141         error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 142                bfd_errmsg (bfd_get_error ()));
 143
 144       for (i = 0; i < number_of_symbols; i++)
 145         {
 146           sym = symbol_table[i];
 147           if (/*sym -> flags & BSF_GLOBAL*/ 1)
 148             {
 149               /* Bfd symbols are section relative. */
 150               symaddr = sym -> value + sym -> section -> vma;
 151               /* Relocate all non-absolute symbols by base address.  */
 152               if (sym -> section != &bfd_abs_section)
 153                 symaddr += addr;
 154
 155               /* For non-absolute symbols, use the type of the section
 156                  they are relative to, to intuit text/data.  BFD provides
 157                  no way of figuring this out for absolute symbols. */
 158               if (sym -> section -> flags & SEC_CODE)
 159                 ms_type = mst_text;
 160               else if (sym -> section -> flags & SEC_DATA)
 161                 ms_type = mst_data;
 162               else
 163                 ms_type = mst_unknown;
 164
 165               record_minimal_symbol ((char *) sym -> name, symaddr, ms_type,
 166                                      objfile);
 167             }
 168         }
 169       do_cleanups (back_to);
 170     }
 171 }
 172
 173
 174 /* Scan and build partial symbols for a symbol file.
 175    We have been initialized by a call to nlm_symfile_init, which
 176    currently does nothing.
 177
 178    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 179    in each section.  We simplify it down to a single offset for all
 180    symbols.  FIXME.
 181
 182    MAINLINE is true if we are reading the main symbol
 183    table (as opposed to a shared lib or dynamically loaded file).
 184
 185    This function only does the minimum work necessary for letting the
 186    user "name" things symbolically; it does not read the entire symtab.
 187    Instead, it reads the external and static symbols and puts them in partial
 188    symbol tables.  When more extensive information is requested of a
 189    file, the corresponding partial symbol table is mutated into a full
 190    fledged symbol table by going back and reading the symbols
 191    for real.
 192
 193    Note that NLM files have two sets of information that is potentially
 194    useful for building gdb's minimal symbol table.  The first is a list
 195    of the publically exported symbols, and is currently used to build
 196    bfd's canonical symbol table.  The second is an optional native debugging
 197    format which contains additional symbols (and possibly duplicates of
 198    the publically exported symbols).  The optional native debugging format
 199    is not currently used. */
 200
 201 static void
 202 nlm_symfile_read (objfile, section_offsets, mainline)
 203      struct objfile *objfile;
 204      struct section_offsets *section_offsets;
 205      int mainline;
 206 {
 207   bfd *abfd = objfile -> obfd;
 208   struct cleanup *back_to;
 209   CORE_ADDR offset;
 210   struct symbol *mainsym;
 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   stabsect_build_psymtabs (objfile, section_offsets, mainline, ".stab",
 225                            ".stabstr", ".text");
 226
 227   mainsym = lookup_symbol ("main", NULL, VAR_NAMESPACE, NULL, NULL);
 228
 229   if (mainsym
 230       && SYMBOL_CLASS(mainsym) == LOC_BLOCK)
 231     {
 232       objfile->ei.main_func_lowpc = BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
 233       objfile->ei.main_func_highpc = BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
 234     }
 235
 236   /* FIXME:  We could locate and read the optional native debugging format
 237      here and add the symbols to the minimal symbol table. */
 238
 239   /* Install any minimal symbols that have been collected as the current
 240      minimal symbols for this objfile. */
 241
 242   install_minimal_symbols (objfile);
 243
 244   do_cleanups (back_to);
 245 }
 246
 247
 248 /* Perform any local cleanups required when we are done with a particular
 249    objfile.  I.E, we are in the process of discarding all symbol information
 250    for an objfile, freeing up all memory held for it, and unlinking the
 251    objfile struct from the global list of known objfiles. */
 252
 253 static void
 254 nlm_symfile_finish (objfile)
 255      struct objfile *objfile;
 256 {
 257   if (objfile -> sym_private != NULL)
 258     {
 259       mfree (objfile -> md, objfile -> sym_private);
 260     }
 261 }
 262
 263 /* NLM specific parsing routine for section offsets.
 264    FIXME:  This may or may not be necessary.  All the symbol readers seem
 265    to have similar code.  See if it can be generalized and moved elsewhere. */
 266
 267 static
 268 struct section_offsets *
 269 nlm_symfile_offsets (objfile, addr)
 270      struct objfile *objfile;
 271      CORE_ADDR addr;
 272 {
 273   struct section_offsets *section_offsets;
 274   int i;
 275
 276   objfile->num_sections = SECT_OFF_MAX;
 277   section_offsets = (struct section_offsets *)
 278     obstack_alloc (&objfile -> psymbol_obstack,
 279                    sizeof (struct section_offsets) +
 280                    sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
 281
 282   for (i = 0; i < SECT_OFF_MAX; i++)
 283     {
 284       ANOFFSET (section_offsets, i) = addr;
 285     }
 286
 287   return (section_offsets);
 288 }
 289
 290 \f
 291 /* Register that we are able to handle NLM file format. */
 292
 293 static struct sym_fns nlm_sym_fns =
 294 {
 295   bfd_target_nlm_flavour,
 296   nlm_new_init,         /* sym_new_init: init anything gbl to entire symtab */
 297   nlm_symfile_init,     /* sym_init: read initial info, setup for sym_read() */
 298   nlm_symfile_read,     /* sym_read: read a symbol file into symtab */
 299   nlm_symfile_finish,   /* sym_finish: finished with file, cleanup */
 300   nlm_symfile_offsets,  /* sym_offsets:  Translate ext. to int. relocation */
 301   NULL                  /* next: pointer to next struct sym_fns */
 302 };
 303
 304 void
 305 _initialize_nlmread ()
 306 {
 307   add_symtab_fns (&nlm_sym_fns);
 308 }