gas/config/obj-aout.c

   1 /* a.out object file format
   2    Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1999, 2000,
   3    2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as
   9    published by the Free Software Foundation; either version 3,
  10    or (at your option) any later version.
  11
  12    GAS is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15    the GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 #define OBJ_HEADER "obj-aout.h"
  23
  24 #include "as.h"
  25 #undef NO_RELOC
  26 #include "aout/aout64.h"
  27 #include "obstack.h"
  28
  29 void
  30 obj_aout_frob_symbol (symbolS *sym, int *punt ATTRIBUTE_UNUSED)
  31 {
  32   flagword flags;
  33   asection *sec;
  34   int desc, type, other;
  35
  36   flags = symbol_get_bfdsym (sym)->flags;
  37   desc = aout_symbol (symbol_get_bfdsym (sym))->desc;
  38   type = aout_symbol (symbol_get_bfdsym (sym))->type;
  39   other = aout_symbol (symbol_get_bfdsym (sym))->other;
  40   sec = S_GET_SEGMENT (sym);
  41
  42   /* Only frob simple symbols this way right now.  */
  43   if (! (type & ~ (N_TYPE | N_EXT)))
  44     {
  45       if (type == (N_UNDF | N_EXT)
  46           && sec == &bfd_abs_section)
  47         {
  48           sec = bfd_und_section_ptr;
  49           S_SET_SEGMENT (sym, sec);
  50         }
  51
  52       if ((type & N_TYPE) != N_INDR
  53           && (type & N_TYPE) != N_SETA
  54           && (type & N_TYPE) != N_SETT
  55           && (type & N_TYPE) != N_SETD
  56           && (type & N_TYPE) != N_SETB
  57           && type != N_WARNING
  58           && (sec == &bfd_abs_section
  59               || sec == &bfd_und_section))
  60         return;
  61       if (flags & BSF_EXPORT)
  62         type |= N_EXT;
  63
  64       switch (type & N_TYPE)
  65         {
  66         case N_SETA:
  67         case N_SETT:
  68         case N_SETD:
  69         case N_SETB:
  70           /* Set the debugging flag for constructor symbols so that
  71              BFD leaves them alone.  */
  72           symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
  73
  74           /* You can't put a common symbol in a set.  The way a set
  75              element works is that the symbol has a definition and a
  76              name, and the linker adds the definition to the set of
  77              that name.  That does not work for a common symbol,
  78              because the linker can't tell which common symbol the
  79              user means.  FIXME: Using as_bad here may be
  80              inappropriate, since the user may want to force a
  81              particular type without regard to the semantics of sets;
  82              on the other hand, we certainly don't want anybody to be
  83              mislead into thinking that their code will work.  */
  84           if (S_IS_COMMON (sym))
  85             as_bad (_("Attempt to put a common symbol into set %s"),
  86                     S_GET_NAME (sym));
  87           /* Similarly, you can't put an undefined symbol in a set.  */
  88           else if (! S_IS_DEFINED (sym))
  89             as_bad (_("Attempt to put an undefined symbol into set %s"),
  90                     S_GET_NAME (sym));
  91
  92           break;
  93         case N_INDR:
  94           /* Put indirect symbols in the indirect section.  */
  95           S_SET_SEGMENT (sym, bfd_ind_section_ptr);
  96           symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT;
  97           if (type & N_EXT)
  98             {
  99               symbol_get_bfdsym (sym)->flags |= BSF_EXPORT;
 100               symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL;
 101             }
 102           break;
 103         case N_WARNING:
 104           /* Mark warning symbols.  */
 105           symbol_get_bfdsym (sym)->flags |= BSF_WARNING;
 106           break;
 107         }
 108     }
 109   else
 110     symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
 111
 112   aout_symbol (symbol_get_bfdsym (sym))->type = type;
 113
 114   /* Double check weak symbols.  */
 115   if (S_IS_WEAK (sym) && S_IS_COMMON (sym))
 116     as_bad (_("Symbol `%s' can not be both weak and common"),
 117             S_GET_NAME (sym));
 118 }
 119
 120 void
 121 obj_aout_frob_file_before_fix (void)
 122 {
 123   /* Relocation processing may require knowing the VMAs of the sections.
 124      Since writing to a section will cause the BFD back end to compute the
 125      VMAs, fake it out here....  */
 126   bfd_byte b = 0;
 127   bfd_boolean x = TRUE;
 128   if (bfd_section_size (stdoutput, text_section) != 0)
 129     x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0,
 130                                   (bfd_size_type) 1);
 131   else if (bfd_section_size (stdoutput, data_section) != 0)
 132     x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0,
 133                                   (bfd_size_type) 1);
 134
 135   assert (x);
 136 }
 137
 138 static void
 139 obj_aout_line (int ignore ATTRIBUTE_UNUSED)
 140 {
 141   /* Assume delimiter is part of expression.
 142      BSD4.2 as fails with delightful bug, so we
 143      are not being incompatible here.  */
 144   new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
 145   demand_empty_rest_of_line ();
 146 }
 147
 148 /* Handle .weak.  This is a GNU extension.  */
 149
 150 static void
 151 obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
 152 {
 153   char *name;
 154   int c;
 155   symbolS *symbolP;
 156
 157   do
 158     {
 159       name = input_line_pointer;
 160       c = get_symbol_end ();
 161       symbolP = symbol_find_or_make (name);
 162       *input_line_pointer = c;
 163       SKIP_WHITESPACE ();
 164       S_SET_WEAK (symbolP);
 165       if (c == ',')
 166         {
 167           input_line_pointer++;
 168           SKIP_WHITESPACE ();
 169           if (*input_line_pointer == '\n')
 170             c = '\n';
 171         }
 172     }
 173   while (c == ',');
 174   demand_empty_rest_of_line ();
 175 }
 176
 177 /* Handle .type.  On {Net,Open}BSD, this is used to set the n_other field,
 178    which is then apparently used when doing dynamic linking.  Older
 179    versions of gas ignored the .type pseudo-op, so we also ignore it if
 180    we can't parse it.  */
 181
 182 static void
 183 obj_aout_type (int ignore ATTRIBUTE_UNUSED)
 184 {
 185   char *name;
 186   int c;
 187   symbolS *sym;
 188
 189   name = input_line_pointer;
 190   c = get_symbol_end ();
 191   sym = symbol_find_or_make (name);
 192   *input_line_pointer = c;
 193   SKIP_WHITESPACE ();
 194   if (*input_line_pointer == ',')
 195     {
 196       ++input_line_pointer;
 197       SKIP_WHITESPACE ();
 198       if (*input_line_pointer == '@')
 199         {
 200           ++input_line_pointer;
 201           if (strncmp (input_line_pointer, "object", 6) == 0)
 202             S_SET_OTHER (sym, 1);
 203           else if (strncmp (input_line_pointer, "function", 8) == 0)
 204             S_SET_OTHER (sym, 2);
 205         }
 206     }
 207
 208   /* Ignore everything else on the line.  */
 209   s_ignore (0);
 210 }
 211
 212 /* Support for an AOUT emulation.  */
 213
 214 static void
 215 aout_pop_insert (void)
 216 {
 217   pop_insert (aout_pseudo_table);
 218 }
 219
 220 static int
 221 obj_aout_s_get_other (symbolS *sym)
 222 {
 223   return aout_symbol (symbol_get_bfdsym (sym))->other;
 224 }
 225
 226 static void
 227 obj_aout_s_set_other (symbolS *sym, int o)
 228 {
 229   aout_symbol (symbol_get_bfdsym (sym))->other = o;
 230 }
 231
 232 static int
 233 obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
 234 {
 235   return obj_sec_sym_ok_for_reloc (sec);
 236 }
 237
 238 static void
 239 obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
 240                        int w,
 241                        const char *s,
 242                        int t,
 243                        int o,
 244                        int d)
 245 {
 246   aout_process_stab (w, s, t, o, d);
 247 }
 248
 249 static int
 250 obj_aout_s_get_desc (symbolS *sym)
 251 {
 252   return aout_symbol (symbol_get_bfdsym (sym))->desc;
 253 }
 254
 255 static void
 256 obj_aout_s_set_desc (symbolS *sym, int d)
 257 {
 258   aout_symbol (symbol_get_bfdsym (sym))->desc = d;
 259 }
 260
 261 static int
 262 obj_aout_s_get_type (symbolS *sym)
 263 {
 264   return aout_symbol (symbol_get_bfdsym (sym))->type;
 265 }
 266
 267 static void
 268 obj_aout_s_set_type (symbolS *sym, int t)
 269 {
 270   aout_symbol (symbol_get_bfdsym (sym))->type = t;
 271 }
 272
 273 static int
 274 obj_aout_separate_stab_sections (void)
 275 {
 276   return 0;
 277 }
 278
 279 /* When changed, make sure these table entries match the single-format
 280    definitions in obj-aout.h.  */
 281
 282 const struct format_ops aout_format_ops =
 283 {
 284   bfd_target_aout_flavour,
 285   1,    /* dfl_leading_underscore.  */
 286   0,    /* emit_section_symbols.  */
 287   0,    /* begin.  */
 288   0,    /* app_file.  */
 289   obj_aout_frob_symbol,
 290   0,    /* frob_file.  */
 291   0,    /* frob_file_before_adjust.  */
 292   obj_aout_frob_file_before_fix,
 293   0,    /* frob_file_after_relocs.  */
 294   0,    /* s_get_size.  */
 295   0,    /* s_set_size.  */
 296   0,    /* s_get_align.  */
 297   0,    /* s_set_align.  */
 298   obj_aout_s_get_other,
 299   obj_aout_s_set_other,
 300   obj_aout_s_get_desc,
 301   obj_aout_s_set_desc,
 302   obj_aout_s_get_type,
 303   obj_aout_s_set_type,
 304   0,    /* copy_symbol_attributes.  */
 305   0,    /* generate_asm_lineno.  */
 306   obj_aout_process_stab,
 307   obj_aout_separate_stab_sections,
 308   0,    /* init_stab_section.  */
 309   obj_aout_sec_sym_ok_for_reloc,
 310   aout_pop_insert,
 311   0,    /* ecoff_set_ext.  */
 312   0,    /* read_begin_hook.  */
 313   0     /* symbol_new_hook.  */
 314 };
 315
 316 const pseudo_typeS aout_pseudo_table[] =
 317 {
 318   {"line", obj_aout_line, 0},   /* Source code line number.  */
 319   {"ln", obj_aout_line, 0},     /* COFF line number that we use anyway.  */
 320
 321   {"weak", obj_aout_weak, 0},   /* Mark symbol as weak.  */
 322
 323   {"type", obj_aout_type, 0},
 324
 325   /* coff debug pseudos (ignored) */
 326   {"def", s_ignore, 0},
 327   {"dim", s_ignore, 0},
 328   {"endef", s_ignore, 0},
 329   {"ident", s_ignore, 0},
 330   {"line", s_ignore, 0},
 331   {"ln", s_ignore, 0},
 332   {"scl", s_ignore, 0},
 333   {"size", s_ignore, 0},
 334   {"tag", s_ignore, 0},
 335   {"val", s_ignore, 0},
 336   {"version", s_ignore, 0},
 337
 338   {"optim", s_ignore, 0},       /* For sun386i cc (?).  */
 339
 340   /* other stuff */
 341   {"ABORT", s_abort, 0},
 342
 343   {NULL, NULL, 0}
 344 };