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, 2009, 2010
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GAS, the GNU Assembler.
   7
   8    GAS is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as
  10    published by the Free Software Foundation; either version 3,
  11    or (at your option) any later version.
  12
  13    GAS is distributed in the hope that it will be useful, but
  14    WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  16    the GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with GAS; see the file COPYING.  If not, write to the Free
  20    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  21    02110-1301, USA.  */
  22
  23 #define OBJ_HEADER "obj-aout.h"
  24
  25 #include "as.h"
  26 #undef NO_RELOC
  27 #include "aout/aout64.h"
  28 #include "obstack.h"
  29
  30 void
  31 obj_aout_frob_symbol (symbolS *sym, int *punt ATTRIBUTE_UNUSED)
  32 {
  33   flagword flags;
  34   asection *sec;
  35   int type;
  36
  37   flags = symbol_get_bfdsym (sym)->flags;
  38   type = aout_symbol (symbol_get_bfdsym (sym))->type;
  39   sec = S_GET_SEGMENT (sym);
  40
  41   /* Only frob simple symbols this way right now.  */
  42   if (! (type & ~ (N_TYPE | N_EXT)))
  43     {
  44       if (type == (N_UNDF | N_EXT)
  45           && sec == &bfd_abs_section)
  46         {
  47           sec = bfd_und_section_ptr;
  48           S_SET_SEGMENT (sym, sec);
  49         }
  50
  51       if ((type & N_TYPE) != N_INDR
  52           && (type & N_TYPE) != N_SETA
  53           && (type & N_TYPE) != N_SETT
  54           && (type & N_TYPE) != N_SETD
  55           && (type & N_TYPE) != N_SETB
  56           && type != N_WARNING
  57           && (sec == &bfd_abs_section
  58               || sec == &bfd_und_section))
  59         return;
  60       if (flags & BSF_EXPORT)
  61         type |= N_EXT;
  62
  63       switch (type & N_TYPE)
  64         {
  65         case N_SETA:
  66         case N_SETT:
  67         case N_SETD:
  68         case N_SETB:
  69           /* Set the debugging flag for constructor symbols so that
  70              BFD leaves them alone.  */
  71           symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
  72
  73           /* You can't put a common symbol in a set.  The way a set
  74              element works is that the symbol has a definition and a
  75              name, and the linker adds the definition to the set of
  76              that name.  That does not work for a common symbol,
  77              because the linker can't tell which common symbol the
  78              user means.  FIXME: Using as_bad here may be
  79              inappropriate, since the user may want to force a
  80              particular type without regard to the semantics of sets;
  81              on the other hand, we certainly don't want anybody to be
  82              mislead into thinking that their code will work.  */
  83           if (S_IS_COMMON (sym))
  84             as_bad (_("Attempt to put a common symbol into set %s"),
  85                     S_GET_NAME (sym));
  86           /* Similarly, you can't put an undefined symbol in a set.  */
  87           else if (! S_IS_DEFINED (sym))
  88             as_bad (_("Attempt to put an undefined symbol into set %s"),
  89                     S_GET_NAME (sym));
  90
  91           break;
  92         case N_INDR:
  93           /* Put indirect symbols in the indirect section.  */
  94           S_SET_SEGMENT (sym, bfd_ind_section_ptr);
  95           symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT;
  96           if (type & N_EXT)
  97             {
  98               symbol_get_bfdsym (sym)->flags |= BSF_EXPORT;
  99               symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL;
 100             }
 101           break;
 102         case N_WARNING:
 103           /* Mark warning symbols.  */
 104           symbol_get_bfdsym (sym)->flags |= BSF_WARNING;
 105           break;
 106         }
 107     }
 108   else
 109     symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
 110
 111   aout_symbol (symbol_get_bfdsym (sym))->type = type;
 112
 113   /* Double check weak symbols.  */
 114   if (S_IS_WEAK (sym) && S_IS_COMMON (sym))
 115     as_bad (_("Symbol `%s' can not be both weak and common"),
 116             S_GET_NAME (sym));
 117 }
 118
 119 void
 120 obj_aout_frob_file_before_fix (void)
 121 {
 122   /* Relocation processing may require knowing the VMAs of the sections.
 123      Since writing to a section will cause the BFD back end to compute the
 124      VMAs, fake it out here....  */
 125   bfd_byte b = 0;
 126   bfd_boolean x = TRUE;
 127   if (bfd_section_size (stdoutput, text_section) != 0)
 128     x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0,
 129                                   (bfd_size_type) 1);
 130   else if (bfd_section_size (stdoutput, data_section) != 0)
 131     x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0,
 132                                   (bfd_size_type) 1);
 133
 134   gas_assert (x);
 135 }
 136
 137 static void
 138 obj_aout_line (int ignore ATTRIBUTE_UNUSED)
 139 {
 140   /* Assume delimiter is part of expression.
 141      BSD4.2 as fails with delightful bug, so we
 142      are not being incompatible here.  */
 143   new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
 144   demand_empty_rest_of_line ();
 145 }
 146
 147 /* Handle .weak.  This is a GNU extension.  */
 148
 149 static void
 150 obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
 151 {
 152   char *name;
 153   int c;
 154   symbolS *symbolP;
 155
 156   do
 157     {
 158       name = input_line_pointer;
 159       c = get_symbol_end ();
 160       symbolP = symbol_find_or_make (name);
 161       *input_line_pointer = c;
 162       SKIP_WHITESPACE ();
 163       S_SET_WEAK (symbolP);
 164       if (c == ',')
 165         {
 166           input_line_pointer++;
 167           SKIP_WHITESPACE ();
 168           if (*input_line_pointer == '\n')
 169             c = '\n';
 170         }
 171     }
 172   while (c == ',');
 173   demand_empty_rest_of_line ();
 174 }
 175
 176 /* Handle .type.  On {Net,Open}BSD, this is used to set the n_other field,
 177    which is then apparently used when doing dynamic linking.  Older
 178    versions of gas ignored the .type pseudo-op, so we also ignore it if
 179    we can't parse it.  */
 180
 181 static void
 182 obj_aout_type (int ignore ATTRIBUTE_UNUSED)
 183 {
 184   char *name;
 185   int c;
 186   symbolS *sym;
 187
 188   name = input_line_pointer;
 189   c = get_symbol_end ();
 190   sym = symbol_find_or_make (name);
 191   *input_line_pointer = c;
 192   SKIP_WHITESPACE ();
 193   if (*input_line_pointer == ',')
 194     {
 195       ++input_line_pointer;
 196       SKIP_WHITESPACE ();
 197       if (*input_line_pointer == '@')
 198         {
 199           ++input_line_pointer;
 200           if (strncmp (input_line_pointer, "object", 6) == 0)
 201             S_SET_OTHER (sym, 1);
 202           else if (strncmp (input_line_pointer, "function", 8) == 0)
 203             S_SET_OTHER (sym, 2);
 204         }
 205     }
 206
 207   /* Ignore everything else on the line.  */
 208   s_ignore (0);
 209 }
 210
 211 /* Support for an AOUT emulation.  */
 212
 213 static void
 214 aout_pop_insert (void)
 215 {
 216   pop_insert (aout_pseudo_table);
 217 }
 218
 219 static int
 220 obj_aout_s_get_other (symbolS *sym)
 221 {
 222   return aout_symbol (symbol_get_bfdsym (sym))->other;
 223 }
 224
 225 static void
 226 obj_aout_s_set_other (symbolS *sym, int o)
 227 {
 228   aout_symbol (symbol_get_bfdsym (sym))->other = o;
 229 }
 230
 231 static int
 232 obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
 233 {
 234   return obj_sec_sym_ok_for_reloc (sec);
 235 }
 236
 237 static void
 238 obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
 239                        int w,
 240                        const char *s,
 241                        int t,
 242                        int o,
 243                        int d)
 244 {
 245   aout_process_stab (w, s, t, o, d);
 246 }
 247
 248 static int
 249 obj_aout_s_get_desc (symbolS *sym)
 250 {
 251   return aout_symbol (symbol_get_bfdsym (sym))->desc;
 252 }
 253
 254 static void
 255 obj_aout_s_set_desc (symbolS *sym, int d)
 256 {
 257   aout_symbol (symbol_get_bfdsym (sym))->desc = d;
 258 }
 259
 260 static int
 261 obj_aout_s_get_type (symbolS *sym)
 262 {
 263   return aout_symbol (symbol_get_bfdsym (sym))->type;
 264 }
 265
 266 static void
 267 obj_aout_s_set_type (symbolS *sym, int t)
 268 {
 269   aout_symbol (symbol_get_bfdsym (sym))->type = t;
 270 }
 271
 272 static int
 273 obj_aout_separate_stab_sections (void)
 274 {
 275   return 0;
 276 }
 277
 278 /* When changed, make sure these table entries match the single-format
 279    definitions in obj-aout.h.  */
 280
 281 const struct format_ops aout_format_ops =
 282 {
 283   bfd_target_aout_flavour,
 284   1,    /* dfl_leading_underscore.  */
 285   0,    /* emit_section_symbols.  */
 286   0,    /* begin.  */
 287   0,    /* app_file.  */
 288   obj_aout_frob_symbol,
 289   0,    /* frob_file.  */
 290   0,    /* frob_file_before_adjust.  */
 291   obj_aout_frob_file_before_fix,
 292   0,    /* frob_file_after_relocs.  */
 293   0,    /* s_get_size.  */
 294   0,    /* s_set_size.  */
 295   0,    /* s_get_align.  */
 296   0,    /* s_set_align.  */
 297   obj_aout_s_get_other,
 298   obj_aout_s_set_other,
 299   obj_aout_s_get_desc,
 300   obj_aout_s_set_desc,
 301   obj_aout_s_get_type,
 302   obj_aout_s_set_type,
 303   0,    /* copy_symbol_attributes.  */
 304   0,    /* generate_asm_lineno.  */
 305   obj_aout_process_stab,
 306   obj_aout_separate_stab_sections,
 307   0,    /* init_stab_section.  */
 308   obj_aout_sec_sym_ok_for_reloc,
 309   aout_pop_insert,
 310   0,    /* ecoff_set_ext.  */
 311   0,    /* read_begin_hook.  */
 312   0,    /* symbol_new_hook.  */
 313   0     /* symbol_clone_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 };