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
  28 static void
  29 nlm_new_init PARAMS ((struct objfile *));
  30
  31 static void
  32 nlm_symfile_init PARAMS ((struct objfile *));
  33
  34 static void
  35 nlm_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
  36
  37 static void
  38 nlm_symfile_finish PARAMS ((struct objfile *));
  39
  40 static void
  41 nlm_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *));
  42
  43 static struct section_offsets *
  44 nlm_symfile_offsets PARAMS ((struct objfile *, CORE_ADDR));
  45
  46 static void
  47 record_minimal_symbol PARAMS ((char *, CORE_ADDR, enum minimal_symbol_type,
  48                                struct objfile *));
  49
  50
  51 /* Initialize anything that needs initializing when a completely new symbol
  52    file is specified (not just adding some symbols from another file, e.g. a
  53    shared library).
  54
  55    We reinitialize buildsym, since gdb will be able to read stabs from an NLM
  56    file at some point in the near future.  */
  57
  58 static void
  59 nlm_new_init (ignore)
  60      struct objfile *ignore;
  61 {
  62   stabsread_new_init ();
  63   buildsym_new_init ();
  64 }
  65
  66
  67 /* NLM specific initialization routine for reading symbols.
  68
  69    It is passed a pointer to a struct sym_fns which contains, among other
  70    things, the BFD for the file whose symbols are being read, and a slot for
  71    a pointer to "private data" which we can fill with goodies.
  72
  73    For now at least, we have nothing in particular to do, so this function is
  74    just a stub. */
  75
  76 static void
  77 nlm_symfile_init (ignore)
  78      struct objfile *ignore;
  79 {
  80 }
  81
  82 static void
  83 record_minimal_symbol (name, address, ms_type, objfile)
  84      char *name;
  85      CORE_ADDR address;
  86      enum minimal_symbol_type ms_type;
  87      struct objfile *objfile;
  88 {
  89   name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
  90   prim_record_minimal_symbol (name, address, ms_type);
  91 }
  92
  93
  94 /*
  95
  96 LOCAL FUNCTION
  97
  98         nlm_symtab_read -- read the symbol table of an NLM file
  99
 100 SYNOPSIS
 101
 102         void nlm_symtab_read (bfd *abfd, CORE_ADDR addr,
 103                               struct objfile *objfile)
 104
 105 DESCRIPTION
 106
 107         Given an open bfd, a base address to relocate symbols to, and a
 108         flag that specifies whether or not this bfd is for an executable
 109         or not (may be shared library for example), add all the global
 110         function and data symbols to the minimal symbol table.
 111 */
 112
 113 static void
 114 nlm_symtab_read (abfd, addr, objfile)
 115      bfd *abfd;
 116      CORE_ADDR addr;
 117      struct objfile *objfile;
 118 {
 119   unsigned int storage_needed;
 120   asymbol *sym;
 121   asymbol **symbol_table;
 122   unsigned int number_of_symbols;
 123   unsigned int i;
 124   struct cleanup *back_to;
 125   CORE_ADDR symaddr;
 126   enum minimal_symbol_type ms_type;
 127
 128   storage_needed = get_symtab_upper_bound (abfd);
 129   if (storage_needed > 0)
 130     {
 131       symbol_table = (asymbol **) xmalloc (storage_needed);
 132       back_to = make_cleanup (free, symbol_table);
 133       number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
 134
 135       for (i = 0; i < number_of_symbols; i++)
 136         {
 137           sym = symbol_table[i];
 138           if (sym -> flags & BSF_GLOBAL)
 139             {
 140               /* Bfd symbols are section relative. */
 141               symaddr = sym -> value + sym -> section -> vma;
 142               /* Relocate all non-absolute symbols by base address.  */
 143               if (sym -> section != &bfd_abs_section)
 144                 {
 145                   symaddr += addr;
 146                 }
 147
 148               /* For non-absolute symbols, use the type of the section
 149                  they are relative to, to intuit text/data.  Bfd provides
 150                  no way of figuring this out for absolute symbols. */
 151               if (sym -> section -> flags & SEC_CODE)
 152                 {
 153                   ms_type = mst_text;
 154                 }
 155               else if (sym -> section -> flags & SEC_DATA)
 156                 {
 157                   ms_type = mst_data;
 158                 }
 159               else
 160                 {
 161                   ms_type = mst_unknown;
 162                 }
 163               record_minimal_symbol ((char *) sym -> name, symaddr, ms_type,
 164                                      objfile);
 165             }
 166         }
 167       do_cleanups (back_to);
 168     }
 169 }
 170
 171
 172 /* Scan and build partial symbols for a symbol file.
 173    We have been initialized by a call to nlm_symfile_init, which
 174    currently does nothing.
 175
 176    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 177    in each section.  We simplify it down to a single offset for all
 178    symbols.  FIXME.
 179
 180    MAINLINE is true if we are reading the main symbol
 181    table (as opposed to a shared lib or dynamically loaded file).
 182
 183    This function only does the minimum work necessary for letting the
 184    user "name" things symbolically; it does not read the entire symtab.
 185    Instead, it reads the external and static symbols and puts them in partial
 186    symbol tables.  When more extensive information is requested of a
 187    file, the corresponding partial symbol table is mutated into a full
 188    fledged symbol table by going back and reading the symbols
 189    for real.
 190
 191    Note that NLM files have two sets of information that is potentially
 192    useful for building gdb's minimal symbol table.  The first is a list
 193    of the publically exported symbols, and is currently used to build
 194    bfd's canonical symbol table.  The second is an optional native debugging
 195    format which contains additional symbols (and possibly duplicates of
 196    the publically exported symbols).  The optional native debugging format
 197    is not currently used. */
 198
 199 static void
 200 nlm_symfile_read (objfile, section_offsets, mainline)
 201      struct objfile *objfile;
 202      struct section_offsets *section_offsets;
 203      int mainline;
 204 {
 205   bfd *abfd = objfile -> obfd;
 206   struct cleanup *back_to;
 207   CORE_ADDR offset;
 208
 209   init_minimal_symbol_collection ();
 210   back_to = make_cleanup (discard_minimal_symbols, 0);
 211
 212   /* FIXME, should take a section_offsets param, not just an offset.  */
 213
 214   offset = ANOFFSET (section_offsets, 0);
 215
 216   /* Process the NLM export records, which become the bfd's canonical symbol
 217      table. */
 218
 219   nlm_symtab_read (abfd, offset, objfile);
 220
 221   /* FIXME:  We could locate and read the optional native debugging format
 222      here and add the symbols to the minimal symbol table. */
 223
 224   if (!have_partial_symbols ())
 225     {
 226       wrap_here ("");
 227       printf_filtered ("(no debugging symbols found)...");
 228       wrap_here ("");
 229     }
 230
 231   /* Install any minimal symbols that have been collected as the current
 232      minimal symbols for this objfile. */
 233
 234   install_minimal_symbols (objfile);
 235
 236   do_cleanups (back_to);
 237 }
 238
 239
 240 /* Perform any local cleanups required when we are done with a particular
 241    objfile.  I.E, we are in the process of discarding all symbol information
 242    for an objfile, freeing up all memory held for it, and unlinking the
 243    objfile struct from the global list of known objfiles. */
 244
 245 static void
 246 nlm_symfile_finish (objfile)
 247      struct objfile *objfile;
 248 {
 249   if (objfile -> sym_private != NULL)
 250     {
 251       mfree (objfile -> md, objfile -> sym_private);
 252     }
 253 }
 254
 255 /* NLM specific parsing routine for section offsets.
 256    FIXME:  This may or may not be necessary.  All the symbol readers seem
 257    to have similar code.  See if it can be generalized and moved elsewhere. */
 258
 259 static
 260 struct section_offsets *
 261 nlm_symfile_offsets (objfile, addr)
 262      struct objfile *objfile;
 263      CORE_ADDR addr;
 264 {
 265   struct section_offsets *section_offsets;
 266   int i;
 267
 268   section_offsets = (struct section_offsets *)
 269     obstack_alloc (&objfile -> psymbol_obstack,
 270                    sizeof (struct section_offsets) +
 271                    sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
 272
 273   for (i = 0; i < SECT_OFF_MAX; i++)
 274     {
 275       ANOFFSET (section_offsets, i) = addr;
 276     }
 277
 278   return (section_offsets);
 279 }
 280
 281 \f
 282 /*  Register that we are able to handle NLM file format. */
 283
 284 static struct sym_fns nlm_sym_fns =
 285 {
 286   "nlm",                /* sym_name: name or name prefix of BFD target type */
 287   3,                    /* sym_namelen: number of significant sym_name chars */
 288   nlm_new_init,         /* sym_new_init: init anything gbl to entire symtab */
 289   nlm_symfile_init,     /* sym_init: read initial info, setup for sym_read() */
 290   nlm_symfile_read,     /* sym_read: read a symbol file into symtab */
 291   nlm_symfile_finish,   /* sym_finish: finished with file, cleanup */
 292   nlm_symfile_offsets,  /* sym_offsets:  Translate ext. to int. relocation */
 293   NULL                  /* next: pointer to next struct sym_fns */
 294 };
 295
 296 void
 297 _initialize_nlmread ()
 298 {
 299   add_symtab_fns (&nlm_sym_fns);
 300 }