gdb/nlmread.c

   1 /* Read NLM (NetWare Loadable Module) format executable files for GDB.
   2    Copyright 1993, 1994, 1995, 1996, 1998, 1999, 2000
   3    Free Software Foundation, Inc.
   4    Written by Fred Fish at Cygnus Support (fnf@cygnus.com).
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "bfd.h"
  25 #include "symtab.h"
  26 #include "symfile.h"
  27 #include "objfiles.h"
  28 #include "buildsym.h"
  29 #include "stabsread.h"
  30
  31 extern void _initialize_nlmread (void);
  32
  33 static void nlm_new_init (struct objfile *);
  34
  35 static void nlm_symfile_init (struct objfile *);
  36
  37 static void nlm_symfile_read (struct objfile *, int);
  38
  39 static void nlm_symfile_finish (struct objfile *);
  40
  41 static void nlm_symtab_read (bfd *, CORE_ADDR, struct objfile *);
  42
  43 /* Initialize anything that needs initializing when a completely new symbol
  44    file is specified (not just adding some symbols from another file, e.g. a
  45    shared library).
  46
  47    We reinitialize buildsym, since gdb will be able to read stabs from an NLM
  48    file at some point in the near future.  */
  49
  50 static void
  51 nlm_new_init (struct objfile *ignore)
  52 {
  53   stabsread_new_init ();
  54   buildsym_new_init ();
  55 }
  56
  57
  58 /* NLM specific initialization routine for reading symbols.
  59
  60    It is passed a pointer to a struct sym_fns which contains, among other
  61    things, the BFD for the file whose symbols are being read, and a slot for
  62    a pointer to "private data" which we can fill with goodies.
  63
  64    For now at least, we have nothing in particular to do, so this function is
  65    just a stub. */
  66
  67 static void
  68 nlm_symfile_init (struct objfile *ignore)
  69 {
  70 }
  71
  72 /*
  73
  74    LOCAL FUNCTION
  75
  76    nlm_symtab_read -- read the symbol table of an NLM file
  77
  78    SYNOPSIS
  79
  80    void nlm_symtab_read (bfd *abfd, CORE_ADDR addr,
  81    struct objfile *objfile)
  82
  83    DESCRIPTION
  84
  85    Given an open bfd, a base address to relocate symbols to, and a
  86    flag that specifies whether or not this bfd is for an executable
  87    or not (may be shared library for example), add all the global
  88    function and data symbols to the minimal symbol table.
  89  */
  90
  91 static void
  92 nlm_symtab_read (bfd *abfd, CORE_ADDR addr, struct objfile *objfile)
  93 {
  94   long storage_needed;
  95   asymbol *sym;
  96   asymbol **symbol_table;
  97   long number_of_symbols;
  98   long i;
  99   struct cleanup *back_to;
 100   CORE_ADDR symaddr;
 101   enum minimal_symbol_type ms_type;
 102
 103   storage_needed = bfd_get_symtab_upper_bound (abfd);
 104   if (storage_needed < 0)
 105     error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 106            bfd_errmsg (bfd_get_error ()));
 107   if (storage_needed > 0)
 108     {
 109       symbol_table = (asymbol **) xmalloc (storage_needed);
 110       back_to = make_cleanup (xfree, symbol_table);
 111       number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 112       if (number_of_symbols < 0)
 113         error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
 114                bfd_errmsg (bfd_get_error ()));
 115
 116       for (i = 0; i < number_of_symbols; i++)
 117         {
 118           sym = symbol_table[i];
 119           if ( /*sym -> flags & BSF_GLOBAL */ 1)
 120             {
 121               /* Bfd symbols are section relative. */
 122               symaddr = sym->value + sym->section->vma;
 123               /* Relocate all non-absolute symbols by base address.  */
 124               if (sym->section != &bfd_abs_section)
 125                 symaddr += addr;
 126
 127               /* For non-absolute symbols, use the type of the section
 128                  they are relative to, to intuit text/data.  BFD provides
 129                  no way of figuring this out for absolute symbols. */
 130               if (sym->section->flags & SEC_CODE)
 131                 ms_type = mst_text;
 132               else if (sym->section->flags & SEC_DATA)
 133                 ms_type = mst_data;
 134               else
 135                 ms_type = mst_unknown;
 136
 137               prim_record_minimal_symbol (sym->name, symaddr, ms_type,
 138                                           objfile);
 139             }
 140         }
 141       do_cleanups (back_to);
 142     }
 143 }
 144
 145
 146 /* Scan and build partial symbols for a symbol file.
 147    We have been initialized by a call to nlm_symfile_init, which
 148    currently does nothing.
 149
 150    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 151    in each section.  We simplify it down to a single offset for all
 152    symbols.  FIXME.
 153
 154    MAINLINE is true if we are reading the main symbol
 155    table (as opposed to a shared lib or dynamically loaded file).
 156
 157    This function only does the minimum work necessary for letting the
 158    user "name" things symbolically; it does not read the entire symtab.
 159    Instead, it reads the external and static symbols and puts them in partial
 160    symbol tables.  When more extensive information is requested of a
 161    file, the corresponding partial symbol table is mutated into a full
 162    fledged symbol table by going back and reading the symbols
 163    for real.
 164
 165    Note that NLM files have two sets of information that is potentially
 166    useful for building gdb's minimal symbol table.  The first is a list
 167    of the publically exported symbols, and is currently used to build
 168    bfd's canonical symbol table.  The second is an optional native debugging
 169    format which contains additional symbols (and possibly duplicates of
 170    the publically exported symbols).  The optional native debugging format
 171    is not currently used. */
 172
 173 static void
 174 nlm_symfile_read (struct objfile *objfile, int mainline)
 175 {
 176   bfd *abfd = objfile->obfd;
 177   struct cleanup *back_to;
 178   CORE_ADDR offset;
 179   struct symbol *mainsym;
 180
 181   init_minimal_symbol_collection ();
 182   back_to = make_cleanup_discard_minimal_symbols ();
 183
 184   /* FIXME, should take a section_offsets param, not just an offset.  */
 185
 186   offset = ANOFFSET (objfile->section_offsets, 0);
 187
 188   /* Process the NLM export records, which become the bfd's canonical symbol
 189      table. */
 190
 191   nlm_symtab_read (abfd, offset, objfile);
 192
 193   stabsect_build_psymtabs (objfile, mainline, ".stab",
 194                            ".stabstr", ".text");
 195
 196   mainsym = lookup_symbol (main_name (), NULL, VAR_NAMESPACE, NULL, NULL);
 197
 198   if (mainsym
 199       && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
 200     {
 201       objfile->ei.main_func_lowpc = BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
 202       objfile->ei.main_func_highpc = BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
 203     }
 204
 205   /* FIXME:  We could locate and read the optional native debugging format
 206      here and add the symbols to the minimal symbol table. */
 207
 208   /* Install any minimal symbols that have been collected as the current
 209      minimal symbols for this objfile. */
 210
 211   install_minimal_symbols (objfile);
 212
 213   do_cleanups (back_to);
 214 }
 215
 216
 217 /* Perform any local cleanups required when we are done with a particular
 218    objfile.  I.E, we are in the process of discarding all symbol information
 219    for an objfile, freeing up all memory held for it, and unlinking the
 220    objfile struct from the global list of known objfiles. */
 221
 222 static void
 223 nlm_symfile_finish (struct objfile *objfile)
 224 {
 225   if (objfile->sym_private != NULL)
 226     {
 227       xmfree (objfile->md, objfile->sym_private);
 228     }
 229 }
 230
 231 /* Register that we are able to handle NLM file format. */
 232
 233 static struct sym_fns nlm_sym_fns =
 234 {
 235   bfd_target_nlm_flavour,
 236   nlm_new_init,                 /* sym_new_init: init anything gbl to entire symtab */
 237   nlm_symfile_init,             /* sym_init: read initial info, setup for sym_read() */
 238   nlm_symfile_read,             /* sym_read: read a symbol file into symtab */
 239   nlm_symfile_finish,           /* sym_finish: finished with file, cleanup */
 240   default_symfile_offsets,      /* sym_offsets:  Translate ext. to int. relocation */
 241   NULL                          /* next: pointer to next struct sym_fns */
 242 };
 243
 244 void
 245 _initialize_nlmread (void)
 246 {
 247   add_symtab_fns (&nlm_sym_fns);
 248 }