gas/config/obj-aout.c

   1 /* a.out object file format
   2    Copyright (C) 1989-2014 Free Software Foundation, Inc.
   3
   4    This file is part of GAS, the GNU Assembler.
   5
   6    GAS is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as
   8    published by the Free Software Foundation; either version 3,
   9    or (at your option) any later version.
  10
  11    GAS is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  14    the GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GAS; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  19    02110-1301, USA.  */
  20
  21 #define OBJ_HEADER "obj-aout.h"
  22
  23 #include "as.h"
  24 #undef NO_RELOC
  25 #include "aout/aout64.h"
  26 #include "obstack.h"
  27
  28 void
  29 obj_aout_frob_symbol (symbolS *sym, int *punt ATTRIBUTE_UNUSED)
  30 {
  31   flagword flags;
  32   asection *sec;
  33   int type;
  34
  35   flags = symbol_get_bfdsym (sym)->flags;
  36   type = aout_symbol (symbol_get_bfdsym (sym))->type;
  37   sec = S_GET_SEGMENT (sym);
  38
  39   /* Only frob simple symbols this way right now.  */
  40   if (! (type & ~ (N_TYPE | N_EXT)))
  41     {
  42       if (type == (N_UNDF | N_EXT)
  43           && sec == bfd_abs_section_ptr)
  44         {
  45           sec = bfd_und_section_ptr;
  46           S_SET_SEGMENT (sym, sec);
  47         }
  48
  49       if ((type & N_TYPE) != N_INDR
  50           && (type & N_TYPE) != N_SETA
  51           && (type & N_TYPE) != N_SETT
  52           && (type & N_TYPE) != N_SETD
  53           && (type & N_TYPE) != N_SETB
  54           && type != N_WARNING
  55           && (sec == bfd_abs_section_ptr
  56               || sec == bfd_und_section_ptr))
  57         return;
  58       if (flags & BSF_EXPORT)
  59         type |= N_EXT;
  60
  61       switch (type & N_TYPE)
  62         {
  63         case N_SETA:
  64         case N_SETT:
  65         case N_SETD:
  66         case N_SETB:
  67           /* Set the debugging flag for constructor symbols so that
  68              BFD leaves them alone.  */
  69           symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
  70
  71           /* You can't put a common symbol in a set.  The way a set
  72              element works is that the symbol has a definition and a
  73              name, and the linker adds the definition to the set of
  74              that name.  That does not work for a common symbol,
  75              because the linker can't tell which common symbol the
  76              user means.  FIXME: Using as_bad here may be
  77              inappropriate, since the user may want to force a
  78              particular type without regard to the semantics of sets;
  79              on the other hand, we certainly don't want anybody to be
  80              mislead into thinking that their code will work.  */
  81           if (S_IS_COMMON (sym))
  82             as_bad (_("Attempt to put a common symbol into set %s"),
  83                     S_GET_NAME (sym));
  84           /* Similarly, you can't put an undefined symbol in a set.  */
  85           else if (! S_IS_DEFINED (sym))
  86             as_bad (_("Attempt to put an undefined symbol into set %s"),
  87                     S_GET_NAME (sym));
  88
  89           break;
  90         case N_INDR:
  91           /* Put indirect symbols in the indirect section.  */
  92           S_SET_SEGMENT (sym, bfd_ind_section_ptr);
  93           symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT;
  94           if (type & N_EXT)
  95             {
  96               symbol_get_bfdsym (sym)->flags |= BSF_EXPORT;
  97               symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL;
  98             }
  99           break;
 100         case N_WARNING:
 101           /* Mark warning symbols.  */
 102           symbol_get_bfdsym (sym)->flags |= BSF_WARNING;
 103           break;
 104         }
 105     }
 106   else
 107     symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
 108
 109   aout_symbol (symbol_get_bfdsym (sym))->type = type;
 110
 111   /* Double check weak symbols.  */
 112   if (S_IS_WEAK (sym) && S_IS_COMMON (sym))
 113     as_bad (_("Symbol `%s' can not be both weak and common"),
 114             S_GET_NAME (sym));
 115 }
 116
 117 void
 118 obj_aout_frob_file_before_fix (void)
 119 {
 120   /* Relocation processing may require knowing the VMAs of the sections.
 121      Since writing to a section will cause the BFD back end to compute the
 122      VMAs, fake it out here....  */
 123   bfd_byte b = 0;
 124   bfd_boolean x = TRUE;
 125   if (bfd_section_size (stdoutput, text_section) != 0)
 126     x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0,
 127                                   (bfd_size_type) 1);
 128   else if (bfd_section_size (stdoutput, data_section) != 0)
 129     x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0,
 130                                   (bfd_size_type) 1);
 131
 132   gas_assert (x);
 133 }
 134
 135 static void
 136 obj_aout_line (int ignore ATTRIBUTE_UNUSED)
 137 {
 138   /* Assume delimiter is part of expression.
 139      BSD4.2 as fails with delightful bug, so we
 140      are not being incompatible here.  */
 141   new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
 142   demand_empty_rest_of_line ();
 143 }
 144
 145 /* Handle .weak.  This is a GNU extension.  */
 146
 147 static void
 148 obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
 149 {
 150   char *name;
 151   int c;
 152   symbolS *symbolP;
 153
 154   do
 155     {
 156       name = input_line_pointer;
 157       c = get_symbol_end ();
 158       symbolP = symbol_find_or_make (name);
 159       *input_line_pointer = c;
 160       SKIP_WHITESPACE ();
 161       S_SET_WEAK (symbolP);
 162       if (c == ',')
 163         {
 164           input_line_pointer++;
 165           SKIP_WHITESPACE ();
 166           if (*input_line_pointer == '\n')
 167             c = '\n';
 168         }
 169     }
 170   while (c == ',');
 171   demand_empty_rest_of_line ();
 172 }
 173
 174 /* Handle .type.  On {Net,Open}BSD, this is used to set the n_other field,
 175    which is then apparently used when doing dynamic linking.  Older
 176    versions of gas ignored the .type pseudo-op, so we also ignore it if
 177    we can't parse it.  */
 178
 179 static void
 180 obj_aout_type (int ignore ATTRIBUTE_UNUSED)
 181 {
 182   char *name;
 183   int c;
 184   symbolS *sym;
 185
 186   name = input_line_pointer;
 187   c = get_symbol_end ();
 188   sym = symbol_find_or_make (name);
 189   *input_line_pointer = c;
 190   SKIP_WHITESPACE ();
 191   if (*input_line_pointer == ',')
 192     {
 193       ++input_line_pointer;
 194       SKIP_WHITESPACE ();
 195       if (*input_line_pointer == '@')
 196         {
 197           ++input_line_pointer;
 198           if (strncmp (input_line_pointer, "object", 6) == 0)
 199             S_SET_OTHER (sym, 1);
 200           else if (strncmp (input_line_pointer, "function", 8) == 0)
 201             S_SET_OTHER (sym, 2);
 202         }
 203     }
 204
 205   /* Ignore everything else on the line.  */
 206   s_ignore (0);
 207 }
 208
 209 /* Support for an AOUT emulation.  */
 210
 211 static void
 212 aout_pop_insert (void)
 213 {
 214   pop_insert (aout_pseudo_table);
 215 }
 216
 217 static int
 218 obj_aout_s_get_other (symbolS *sym)
 219 {
 220   return aout_symbol (symbol_get_bfdsym (sym))->other;
 221 }
 222
 223 static void
 224 obj_aout_s_set_other (symbolS *sym, int o)
 225 {
 226   aout_symbol (symbol_get_bfdsym (sym))->other = o;
 227 }
 228
 229 static int
 230 obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
 231 {
 232   return obj_sec_sym_ok_for_reloc (sec);
 233 }
 234
 235 static void
 236 obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
 237                        int w,
 238                        const char *s,
 239                        int t,
 240                        int o,
 241                        int d)
 242 {
 243   aout_process_stab (w, s, t, o, d);
 244 }
 245
 246 static int
 247 obj_aout_s_get_desc (symbolS *sym)
 248 {
 249   return aout_symbol (symbol_get_bfdsym (sym))->desc;
 250 }
 251
 252 static void
 253 obj_aout_s_set_desc (symbolS *sym, int d)
 254 {
 255   aout_symbol (symbol_get_bfdsym (sym))->desc = d;
 256 }
 257
 258 static int
 259 obj_aout_s_get_type (symbolS *sym)
 260 {
 261   return aout_symbol (symbol_get_bfdsym (sym))->type;
 262 }
 263
 264 static void
 265 obj_aout_s_set_type (symbolS *sym, int t)
 266 {
 267   aout_symbol (symbol_get_bfdsym (sym))->type = t;
 268 }
 269
 270 static int
 271 obj_aout_separate_stab_sections (void)
 272 {
 273   return 0;
 274 }
 275
 276 /* When changed, make sure these table entries match the single-format
 277    definitions in obj-aout.h.  */
 278
 279 const struct format_ops aout_format_ops =
 280 {
 281   bfd_target_aout_flavour,
 282   1,    /* dfl_leading_underscore.  */
 283   0,    /* emit_section_symbols.  */
 284   0,    /* begin.  */
 285   0,    /* app_file.  */
 286   obj_aout_frob_symbol,
 287   0,    /* frob_file.  */
 288   0,    /* frob_file_before_adjust.  */
 289   obj_aout_frob_file_before_fix,
 290   0,    /* frob_file_after_relocs.  */
 291   0,    /* s_get_size.  */
 292   0,    /* s_set_size.  */
 293   0,    /* s_get_align.  */
 294   0,    /* s_set_align.  */
 295   obj_aout_s_get_other,
 296   obj_aout_s_set_other,
 297   obj_aout_s_get_desc,
 298   obj_aout_s_set_desc,
 299   obj_aout_s_get_type,
 300   obj_aout_s_set_type,
 301   0,    /* copy_symbol_attributes.  */
 302   0,    /* generate_asm_lineno.  */
 303   obj_aout_process_stab,
 304   obj_aout_separate_stab_sections,
 305   0,    /* init_stab_section.  */
 306   obj_aout_sec_sym_ok_for_reloc,
 307   aout_pop_insert,
 308   0,    /* ecoff_set_ext.  */
 309   0,    /* read_begin_hook.  */
 310   0,    /* symbol_new_hook.  */
 311   0,    /* symbol_clone_hook.  */
 312   0     /* adjust_symtab.  */
 313 };
 314
 315 const pseudo_typeS aout_pseudo_table[] =
 316 {
 317   {"line", obj_aout_line, 0},   /* Source code line number.  */
 318   {"ln", obj_aout_line, 0},     /* COFF line number that we use anyway.  */
 319
 320   {"weak", obj_aout_weak, 0},   /* Mark symbol as weak.  */
 321
 322   {"type", obj_aout_type, 0},
 323
 324   /* coff debug pseudos (ignored) */
 325   {"def", s_ignore, 0},
 326   {"dim", s_ignore, 0},
 327   {"endef", s_ignore, 0},
 328   {"ident", s_ignore, 0},
 329   {"line", s_ignore, 0},
 330   {"ln", s_ignore, 0},
 331   {"scl", s_ignore, 0},
 332   {"size", s_ignore, 0},
 333   {"tag", s_ignore, 0},
 334   {"val", s_ignore, 0},
 335   {"version", s_ignore, 0},
 336
 337   {"optim", s_ignore, 0},       /* For sun386i cc (?).  */
 338
 339   /* other stuff */
 340   {"ABORT", s_abort, 0},
 341
 342   {NULL, NULL, 0}
 343 };