gas/config/obj-aout.c

   1 /* a.out object file format
   2    Copyright (C) 1989-2019 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
  27 void
  28 obj_aout_frob_symbol (symbolS *sym, int *punt ATTRIBUTE_UNUSED)
  29 {
  30   flagword flags;
  31   asection *sec;
  32   int type;
  33
  34   flags = symbol_get_bfdsym (sym)->flags;
  35   type = aout_symbol (symbol_get_bfdsym (sym))->type;
  36   sec = S_GET_SEGMENT (sym);
  37
  38   /* Only frob simple symbols this way right now.  */
  39   if (! (type & ~ (N_TYPE | N_EXT)))
  40     {
  41       if (type == (N_UNDF | N_EXT)
  42           && sec == bfd_abs_section_ptr)
  43         {
  44           sec = bfd_und_section_ptr;
  45           S_SET_SEGMENT (sym, sec);
  46         }
  47
  48       if ((type & N_TYPE) != N_INDR
  49           && (type & N_TYPE) != N_SETA
  50           && (type & N_TYPE) != N_SETT
  51           && (type & N_TYPE) != N_SETD
  52           && (type & N_TYPE) != N_SETB
  53           && type != N_WARNING
  54           && (sec == bfd_abs_section_ptr
  55               || sec == bfd_und_section_ptr))
  56         return;
  57       if (flags & BSF_EXPORT)
  58         type |= N_EXT;
  59
  60       switch (type & N_TYPE)
  61         {
  62         case N_SETA:
  63         case N_SETT:
  64         case N_SETD:
  65         case N_SETB:
  66           /* Set the debugging flag for constructor symbols so that
  67              BFD leaves them alone.  */
  68           symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
  69
  70           /* You can't put a common symbol in a set.  The way a set
  71              element works is that the symbol has a definition and a
  72              name, and the linker adds the definition to the set of
  73              that name.  That does not work for a common symbol,
  74              because the linker can't tell which common symbol the
  75              user means.  FIXME: Using as_bad here may be
  76              inappropriate, since the user may want to force a
  77              particular type without regard to the semantics of sets;
  78              on the other hand, we certainly don't want anybody to be
  79              mislead into thinking that their code will work.  */
  80           if (S_IS_COMMON (sym))
  81             as_bad (_("Attempt to put a common symbol into set %s"),
  82                     S_GET_NAME (sym));
  83           /* Similarly, you can't put an undefined symbol in a set.  */
  84           else if (! S_IS_DEFINED (sym))
  85             as_bad (_("Attempt to put an undefined symbol into set %s"),
  86                     S_GET_NAME (sym));
  87
  88           break;
  89         case N_INDR:
  90           /* Put indirect symbols in the indirect section.  */
  91           S_SET_SEGMENT (sym, bfd_ind_section_ptr);
  92           symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT;
  93           if (type & N_EXT)
  94             {
  95               symbol_get_bfdsym (sym)->flags |= BSF_EXPORT;
  96               symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL;
  97             }
  98           break;
  99         case N_WARNING:
 100           /* Mark warning symbols.  */
 101           symbol_get_bfdsym (sym)->flags |= BSF_WARNING;
 102           break;
 103         }
 104     }
 105   else
 106     symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
 107
 108   aout_symbol (symbol_get_bfdsym (sym))->type = type;
 109
 110   /* Double check weak symbols.  */
 111   if (S_IS_WEAK (sym) && S_IS_COMMON (sym))
 112     as_bad (_("Symbol `%s' can not be both weak and common"),
 113             S_GET_NAME (sym));
 114 }
 115
 116 void
 117 obj_aout_frob_file_before_fix (void)
 118 {
 119   /* Relocation processing may require knowing the VMAs of the sections.
 120      Since writing to a section will cause the BFD back end to compute the
 121      VMAs, fake it out here....
 122      Writing to the end of the section ensures the file contents
 123      extend to cover the entire aligned size.  We possibly won't know
 124      the aligned size until after VMAs and sizes are set on the first
 125      bfd_set_section_contents call, so it might be necessary to repeat.  */
 126   asection *sec = NULL;
 127   if (data_section->size != 0)
 128     sec = data_section;
 129   else if (text_section->size != 0)
 130     sec = text_section;
 131   if (sec)
 132     {
 133       bfd_size_type size;
 134       do
 135         {
 136           bfd_byte b = 0;
 137           size = sec->size;
 138           gas_assert (bfd_set_section_contents (stdoutput, sec, &b,
 139                                                 size - 1, (bfd_size_type) 1));
 140         } while (size != sec->size);
 141     }
 142 }
 143
 144 static void
 145 obj_aout_line (int ignore ATTRIBUTE_UNUSED)
 146 {
 147   /* Assume delimiter is part of expression.
 148      BSD4.2 as fails with delightful bug, so we
 149      are not being incompatible here.  */
 150   new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
 151   demand_empty_rest_of_line ();
 152 }
 153
 154 /* Handle .weak.  This is a GNU extension.  */
 155
 156 static void
 157 obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
 158 {
 159   char *name;
 160   int c;
 161   symbolS *symbolP;
 162
 163   do
 164     {
 165       c = get_symbol_name (&name);
 166       symbolP = symbol_find_or_make (name);
 167       (void) restore_line_pointer (c);
 168       SKIP_WHITESPACE ();
 169       S_SET_WEAK (symbolP);
 170       if (c == ',')
 171         {
 172           input_line_pointer++;
 173           SKIP_WHITESPACE ();
 174           if (*input_line_pointer == '\n')
 175             c = '\n';
 176         }
 177     }
 178   while (c == ',');
 179   demand_empty_rest_of_line ();
 180 }
 181
 182 /* Handle .type.  On {Net,Open}BSD, this is used to set the n_other field,
 183    which is then apparently used when doing dynamic linking.  Older
 184    versions of gas ignored the .type pseudo-op, so we also ignore it if
 185    we can't parse it.  */
 186
 187 static void
 188 obj_aout_type (int ignore ATTRIBUTE_UNUSED)
 189 {
 190   char *name;
 191   int c;
 192   symbolS *sym;
 193
 194   c = get_symbol_name (&name);
 195   sym = symbol_find_or_make (name);
 196   (void) restore_line_pointer (c);
 197   SKIP_WHITESPACE ();
 198   if (*input_line_pointer == ',')
 199     {
 200       ++input_line_pointer;
 201       SKIP_WHITESPACE ();
 202       if (*input_line_pointer == '@')
 203         {
 204           ++input_line_pointer;
 205           if (strncmp (input_line_pointer, "object", 6) == 0)
 206             S_SET_OTHER (sym, 1);
 207           else if (strncmp (input_line_pointer, "function", 8) == 0)
 208             S_SET_OTHER (sym, 2);
 209         }
 210     }
 211
 212   /* Ignore everything else on the line.  */
 213   s_ignore (0);
 214 }
 215
 216 /* Support for an AOUT emulation.  */
 217
 218 static void
 219 aout_pop_insert (void)
 220 {
 221   pop_insert (aout_pseudo_table);
 222 }
 223
 224 static int
 225 obj_aout_s_get_other (symbolS *sym)
 226 {
 227   return aout_symbol (symbol_get_bfdsym (sym))->other;
 228 }
 229
 230 static void
 231 obj_aout_s_set_other (symbolS *sym, int o)
 232 {
 233   aout_symbol (symbol_get_bfdsym (sym))->other = o;
 234 }
 235
 236 static int
 237 obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
 238 {
 239   return obj_sec_sym_ok_for_reloc (sec);
 240 }
 241
 242 static void
 243 obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
 244                        int w,
 245                        const char *s,
 246                        int t,
 247                        int o,
 248                        int d)
 249 {
 250   aout_process_stab (w, s, t, o, d);
 251 }
 252
 253 static int
 254 obj_aout_s_get_desc (symbolS *sym)
 255 {
 256   return aout_symbol (symbol_get_bfdsym (sym))->desc;
 257 }
 258
 259 static void
 260 obj_aout_s_set_desc (symbolS *sym, int d)
 261 {
 262   aout_symbol (symbol_get_bfdsym (sym))->desc = d;
 263 }
 264
 265 static int
 266 obj_aout_s_get_type (symbolS *sym)
 267 {
 268   return aout_symbol (symbol_get_bfdsym (sym))->type;
 269 }
 270
 271 static void
 272 obj_aout_s_set_type (symbolS *sym, int t)
 273 {
 274   aout_symbol (symbol_get_bfdsym (sym))->type = t;
 275 }
 276
 277 static int
 278 obj_aout_separate_stab_sections (void)
 279 {
 280   return 0;
 281 }
 282
 283 /* When changed, make sure these table entries match the single-format
 284    definitions in obj-aout.h.  */
 285
 286 const struct format_ops aout_format_ops =
 287 {
 288   bfd_target_aout_flavour,
 289   1,    /* dfl_leading_underscore.  */
 290   0,    /* emit_section_symbols.  */
 291   0,    /* begin.  */
 292   0,    /* app_file.  */
 293   obj_aout_frob_symbol,
 294   0,    /* frob_file.  */
 295   0,    /* frob_file_before_adjust.  */
 296   obj_aout_frob_file_before_fix,
 297   0,    /* frob_file_after_relocs.  */
 298   0,    /* s_get_size.  */
 299   0,    /* s_set_size.  */
 300   0,    /* s_get_align.  */
 301   0,    /* s_set_align.  */
 302   obj_aout_s_get_other,
 303   obj_aout_s_set_other,
 304   obj_aout_s_get_desc,
 305   obj_aout_s_set_desc,
 306   obj_aout_s_get_type,
 307   obj_aout_s_set_type,
 308   0,    /* copy_symbol_attributes.  */
 309   0,    /* generate_asm_lineno.  */
 310   obj_aout_process_stab,
 311   obj_aout_separate_stab_sections,
 312   0,    /* init_stab_section.  */
 313   obj_aout_sec_sym_ok_for_reloc,
 314   aout_pop_insert,
 315   0,    /* ecoff_set_ext.  */
 316   0,    /* read_begin_hook.  */
 317   0,    /* symbol_new_hook.  */
 318   0,    /* symbol_clone_hook.  */
 319   0     /* adjust_symtab.  */
 320 };
 321
 322 const pseudo_typeS aout_pseudo_table[] =
 323 {
 324   {"line", obj_aout_line, 0},   /* Source code line number.  */
 325   {"ln", obj_aout_line, 0},     /* COFF line number that we use anyway.  */
 326
 327   {"weak", obj_aout_weak, 0},   /* Mark symbol as weak.  */
 328
 329   {"type", obj_aout_type, 0},
 330
 331   /* coff debug pseudos (ignored) */
 332   {"def", s_ignore, 0},
 333   {"dim", s_ignore, 0},
 334   {"endef", s_ignore, 0},
 335   {"ident", s_ignore, 0},
 336   {"line", s_ignore, 0},
 337   {"ln", s_ignore, 0},
 338   {"scl", s_ignore, 0},
 339   {"size", s_ignore, 0},
 340   {"tag", s_ignore, 0},
 341   {"val", s_ignore, 0},
 342   {"version", s_ignore, 0},
 343
 344   {"optim", s_ignore, 0},       /* For sun386i cc (?).  */
 345
 346   /* other stuff */
 347   {"ABORT", s_abort, 0},
 348
 349   {NULL, NULL, 0}
 350 };