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