gdb/nlmread.c

   1 /* Read NLM (NetWare Loadable Module) format executable files for GDB.
   2    Copyright 1993 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 "bfd.h"
  23 #include "symtab.h"
  24 #include "symfile.h"
  25 #include "objfiles.h"
  26 #include "gdb-stabs.h"
  27 #include "buildsym.h"
  28 #include "stabsread.h"
  29
  30 static void
  31 nlm_new_init PARAMS ((struct objfile *));
  32
  33 static void
  34 nlm_symfile_init PARAMS ((struct objfile *));
  35
  36 static void
  37 nlm_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
  38
  39 static void
  40 nlm_symfile_finish PARAMS ((struct objfile *));
  41
  42 static void
  43 nlm_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *));
  44
  45 static struct section_offsets *
  46 nlm_symfile_offsets PARAMS ((struct objfile *, CORE_ADDR));
  47
  48 static void
  49 record_minimal_symbol PARAMS ((char *, CORE_ADDR, enum minimal_symbol_type,
  50                                struct objfile *));
  51
  52
  53 /* Initialize anything that needs initializing when a completely new symbol
  54    file is specified (not just adding some symbols from another file, e.g. a
  55    shared library).
  56
  57    We reinitialize buildsym, since gdb will be able to read stabs from an NLM
  58    file at some point in the near future.  */
  59
  60 static void
  61 nlm_new_init (ignore)
  62      struct objfile *ignore;
  63 {
  64   stabsread_new_init ();
  65   buildsym_new_init ();
  66 }
  67
  68
  69 /* NLM specific initialization routine for reading symbols.
  70
  71    It is passed a pointer to a struct sym_fns which contains, among other
  72    things, the BFD for the file whose symbols are being read, and a slot for
  73    a pointer to "private data" which we can fill with goodies.
  74
  75    For now at least, we have nothing in particular to do, so this function is
  76    just a stub. */
  77
  78 static void
  79 nlm_symfile_init (ignore)
  80      struct objfile *ignore;
  81 {
  82 }
  83
  84 static void
  85 record_minimal_symbol (name, address, ms_type, objfile)
  86      char *name;
  87      CORE_ADDR address;
  88      enum minimal_symbol_type ms_type;
  89      struct objfile *objfile;
  90 {
  91   name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
  92   prim_record_minimal_symbol (name, address, ms_type);
  93 }
  94
  95
  96 /*
  97
  98 LOCAL FUNCTION
  99
 100         nlm_symtab_read -- read the symbol table of an NLM file
 101
 102 SYNOPSIS
 103
 104         void nlm_symtab_read (bfd *abfd, CORE_ADDR addr,
 105                               struct objfile *objfile)
 106
 107 DESCRIPTION
 108
 109         Given an open bfd, a base address to relocate symbols to, and a
 110         flag that specifies whether or not this bfd is for an executable
 111         or not (may be shared library for example), add all the global
 112         function and data symbols to the minimal symbol table.
 113 */
 114
 115 static void
 116 nlm_symtab_read (abfd, addr, objfile)
 117      bfd *abfd;
 118      CORE_ADDR addr;
 119      struct objfile *objfile;
 120 {
 121   unsigned int storage_needed;
 122   asymbol *sym;
 123   asymbol **symbol_table;
 124   unsigned int number_of_symbols;
 125   unsigned int i;
 126   struct cleanup *back_to;
 127   CORE_ADDR symaddr;
 128   enum minimal_symbol_type ms_type;
 129
 130   storage_needed = get_symtab_upper_bound (abfd);
 131   if (storage_needed > 0)
 132     {
 133       symbol_table = (asymbol **) xmalloc (storage_needed);
 134       back_to = make_cleanup (free, symbol_table);
 135       number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 136
 137       for (i = 0; i < number_of_symbols; i++)
 138         {
 139           sym = symbol_table[i];
 140           if (sym -> flags & BSF_GLOBAL)
 141             {
 142               /* Bfd symbols are section relative. */
 143               symaddr = sym -> value + sym -> section -> vma;
 144               /* Relocate all non-absolute symbols by base address.  */
 145               if (sym -> section != &bfd_abs_section)
 146                 {
 147                   symaddr += addr;
 148                 }
 149
 150               /* For non-absolute symbols, use the type of the section
 151                  they are relative to, to intuit text/data.  Bfd provides
 152                  no way of figuring this out for absolute symbols. */
 153               if (sym -> section -> flags & SEC_CODE)
 154                 {
 155                   ms_type = mst_text;
 156                 }
 157               else if (sym -> section -> flags & SEC_DATA)
 158                 {
 159                   ms_type = mst_data;
 160                 }
 161               else
 162                 {
 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
 211   init_minimal_symbol_collection ();
 212   back_to = make_cleanup (discard_minimal_symbols, 0);
 213
 214   /* FIXME, should take a section_offsets param, not just an offset.  */
 215
 216   offset = ANOFFSET (section_offsets, 0);
 217
 218   /* Process the NLM export records, which become the bfd's canonical symbol
 219      table. */
 220
 221   nlm_symtab_read (abfd, offset, objfile);
 222
 223   /* FIXME:  We could locate and read the optional native debugging format
 224      here and add the symbols to the minimal symbol table. */
 225
 226   if (!have_partial_symbols ())
 227     {
 228       wrap_here ("");
 229       printf_filtered ("(no debugging symbols found)...");
 230       wrap_here ("");
 231     }
 232
 233   /* Install any minimal symbols that have been collected as the current
 234      minimal symbols for this objfile. */
 235
 236   install_minimal_symbols (objfile);
 237
 238   do_cleanups (back_to);
 239 }
 240
 241
 242 /* Perform any local cleanups required when we are done with a particular
 243    objfile.  I.E, we are in the process of discarding all symbol information
 244    for an objfile, freeing up all memory held for it, and unlinking the
 245    objfile struct from the global list of known objfiles. */
 246
 247 static void
 248 nlm_symfile_finish (objfile)
 249      struct objfile *objfile;
 250 {
 251   if (objfile -> sym_private != NULL)
 252     {
 253       mfree (objfile -> md, objfile -> sym_private);
 254     }
 255 }
 256
 257 /* NLM specific parsing routine for section offsets.
 258    FIXME:  This may or may not be necessary.  All the symbol readers seem
 259    to have similar code.  See if it can be generalized and moved elsewhere. */
 260
 261 static
 262 struct section_offsets *
 263 nlm_symfile_offsets (objfile, addr)
 264      struct objfile *objfile;
 265      CORE_ADDR addr;
 266 {
 267   struct section_offsets *section_offsets;
 268   int i;
 269
 270   objfile->num_sections = SECT_OFF_MAX;
 271   section_offsets = (struct section_offsets *)
 272     obstack_alloc (&objfile -> psymbol_obstack,
 273                    sizeof (struct section_offsets) +
 274                    sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
 275
 276   for (i = 0; i < SECT_OFF_MAX; i++)
 277     {
 278       ANOFFSET (section_offsets, i) = addr;
 279     }
 280
 281   return (section_offsets);
 282 }
 283
 284 \f
 285 /* Register that we are able to handle NLM file format. */
 286
 287 static struct sym_fns nlm_sym_fns =
 288 {
 289   "nlm",                /* sym_name: name or name prefix of BFD target type */
 290   3,                    /* sym_namelen: number of significant sym_name chars */
 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 }