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,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "gdb_string.h"
  24 #include "bfd.h"
  25 #include "symtab.h"
  26 #include "symfile.h"
  27 #include "objfiles.h"
  28 #include "gdb-stabs.h"
  29 #include "buildsym.h"
  30 #include "stabsread.h"
  31
  32 extern void _initialize_nlmread PARAMS ((void));
  33
  34 static void
  35 nlm_new_init PARAMS ((struct objfile *));
  36
  37 static void
  38 nlm_symfile_init PARAMS ((struct objfile *));
  39
  40 static void
  41 nlm_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
  42
  43 static void
  44 nlm_symfile_finish PARAMS ((struct objfile *));
  45
  46 static void
  47 nlm_symtab_read PARAMS ((bfd *, CORE_ADDR, struct objfile *));
  48
  49 /* Initialize anything that needs initializing when a completely new symbol
  50    file is specified (not just adding some symbols from another file, e.g. a
  51    shared library).
  52
  53    We reinitialize buildsym, since gdb will be able to read stabs from an NLM
  54    file at some point in the near future.  */
  55
  56 static void
  57 nlm_new_init (ignore)
  58      struct objfile *ignore;
  59 {
  60   stabsread_new_init ();
  61   buildsym_new_init ();
  62 }
  63
  64
  65 /* NLM specific initialization routine for reading symbols.
  66
  67    It is passed a pointer to a struct sym_fns which contains, among other
  68    things, the BFD for the file whose symbols are being read, and a slot for
  69    a pointer to "private data" which we can fill with goodies.
  70
  71    For now at least, we have nothing in particular to do, so this function is
  72    just a stub. */
  73
  74 static void
  75 nlm_symfile_init (ignore)
  76      struct objfile *ignore;
  77 {
  78 }
  79
  80 /*
  81
  82    LOCAL FUNCTION
  83
  84    nlm_symtab_read -- read the symbol table of an NLM file
  85
  86    SYNOPSIS
  87
  88    void nlm_symtab_read (bfd *abfd, CORE_ADDR addr,
  89    struct objfile *objfile)
  90
  91    DESCRIPTION
  92
  93    Given an open bfd, a base address to relocate symbols to, and a
  94    flag that specifies whether or not this bfd is for an executable
  95    or not (may be shared library for example), add all the global
  96    function and data symbols to the minimal symbol table.
  97  */
  98
  99 static void
 100 nlm_symtab_read (abfd, addr, objfile)
 101      bfd *abfd;
 102      CORE_ADDR addr;
 103      struct objfile *objfile;
 104 {
 105   long storage_needed;
 106   asymbol *sym;
 107   asymbol **symbol_table;
 108   long number_of_symbols;
 109   long i;
 110   struct cleanup *back_to;
 111   CORE_ADDR symaddr;
 112   enum minimal_symbol_type ms_type;
 113
 114   storage_needed = bfd_get_symtab_upper_bound (abfd);
 115   if (storage_needed < 0)
 116     error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 117            bfd_errmsg (bfd_get_error ()));
 118   if (storage_needed > 0)
 119     {
 120       symbol_table = (asymbol **) xmalloc (storage_needed);
 121       back_to = make_cleanup (free, symbol_table);
 122       number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 123       if (number_of_symbols < 0)
 124         error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 125                bfd_errmsg (bfd_get_error ()));
 126
 127       for (i = 0; i < number_of_symbols; i++)
 128         {
 129           sym = symbol_table[i];
 130           if ( /*sym -> flags & BSF_GLOBAL */ 1)
 131             {
 132               /* Bfd symbols are section relative. */
 133               symaddr = sym->value + sym->section->vma;
 134               /* Relocate all non-absolute symbols by base address.  */
 135               if (sym->section != &bfd_abs_section)
 136                 symaddr += addr;
 137
 138               /* For non-absolute symbols, use the type of the section
 139                  they are relative to, to intuit text/data.  BFD provides
 140                  no way of figuring this out for absolute symbols. */
 141               if (sym->section->flags & SEC_CODE)
 142                 ms_type = mst_text;
 143               else if (sym->section->flags & SEC_DATA)
 144                 ms_type = mst_data;
 145               else
 146                 ms_type = mst_unknown;
 147
 148               prim_record_minimal_symbol (sym->name, symaddr, ms_type,
 149                                           objfile);
 150             }
 151         }
 152       do_cleanups (back_to);
 153     }
 154 }
 155
 156
 157 /* Scan and build partial symbols for a symbol file.
 158    We have been initialized by a call to nlm_symfile_init, which
 159    currently does nothing.
 160
 161    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 162    in each section.  We simplify it down to a single offset for all
 163    symbols.  FIXME.
 164
 165    MAINLINE is true if we are reading the main symbol
 166    table (as opposed to a shared lib or dynamically loaded file).
 167
 168    This function only does the minimum work necessary for letting the
 169    user "name" things symbolically; it does not read the entire symtab.
 170    Instead, it reads the external and static symbols and puts them in partial
 171    symbol tables.  When more extensive information is requested of a
 172    file, the corresponding partial symbol table is mutated into a full
 173    fledged symbol table by going back and reading the symbols
 174    for real.
 175
 176    Note that NLM files have two sets of information that is potentially
 177    useful for building gdb's minimal symbol table.  The first is a list
 178    of the publically exported symbols, and is currently used to build
 179    bfd's canonical symbol table.  The second is an optional native debugging
 180    format which contains additional symbols (and possibly duplicates of
 181    the publically exported symbols).  The optional native debugging format
 182    is not currently used. */
 183
 184 static void
 185 nlm_symfile_read (objfile, section_offsets, mainline)
 186      struct objfile *objfile;
 187      struct section_offsets *section_offsets;
 188      int mainline;
 189 {
 190   bfd *abfd = objfile->obfd;
 191   struct cleanup *back_to;
 192   CORE_ADDR offset;
 193   struct symbol *mainsym;
 194
 195   init_minimal_symbol_collection ();
 196   back_to = make_cleanup ((make_cleanup_func) discard_minimal_symbols, 0);
 197
 198   /* FIXME, should take a section_offsets param, not just an offset.  */
 199
 200   offset = ANOFFSET (section_offsets, 0);
 201
 202   /* Process the NLM export records, which become the bfd's canonical symbol
 203      table. */
 204
 205   nlm_symtab_read (abfd, offset, objfile);
 206
 207   stabsect_build_psymtabs (objfile, section_offsets, mainline, ".stab",
 208                            ".stabstr", ".text");
 209
 210   mainsym = lookup_symbol ("main", NULL, VAR_NAMESPACE, NULL, NULL);
 211
 212   if (mainsym
 213       && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
 214     {
 215       objfile->ei.main_func_lowpc = BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
 216       objfile->ei.main_func_highpc = BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
 217     }
 218
 219   /* FIXME:  We could locate and read the optional native debugging format
 220      here and add the symbols to the minimal symbol table. */
 221
 222   /* Install any minimal symbols that have been collected as the current
 223      minimal symbols for this objfile. */
 224
 225   install_minimal_symbols (objfile);
 226
 227   do_cleanups (back_to);
 228 }
 229
 230
 231 /* Perform any local cleanups required when we are done with a particular
 232    objfile.  I.E, we are in the process of discarding all symbol information
 233    for an objfile, freeing up all memory held for it, and unlinking the
 234    objfile struct from the global list of known objfiles. */
 235
 236 static void
 237 nlm_symfile_finish (objfile)
 238      struct objfile *objfile;
 239 {
 240   if (objfile->sym_private != NULL)
 241     {
 242       mfree (objfile->md, objfile->sym_private);
 243     }
 244 }
 245
 246 /* Register that we are able to handle NLM file format. */
 247
 248 static struct sym_fns nlm_sym_fns =
 249 {
 250   bfd_target_nlm_flavour,
 251   nlm_new_init,                 /* sym_new_init: init anything gbl to entire symtab */
 252   nlm_symfile_init,             /* sym_init: read initial info, setup for sym_read() */
 253   nlm_symfile_read,             /* sym_read: read a symbol file into symtab */
 254   nlm_symfile_finish,           /* sym_finish: finished with file, cleanup */
 255   default_symfile_offsets,
 256                         /* sym_offsets:  Translate ext. to int. relocation */
 257   NULL                          /* next: pointer to next struct sym_fns */
 258 };
 259
 260 void
 261 _initialize_nlmread ()
 262 {
 263   add_symtab_fns (&nlm_sym_fns);
 264 }