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   bfd_byte b = 0;
 123   bfd_boolean x = TRUE;
 124   if (bfd_section_size (stdoutput, text_section) != 0)
 125     x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0,
 126                                   (bfd_size_type) 1);
 127   else if (bfd_section_size (stdoutput, data_section) != 0)
 128     x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0,
 129                                   (bfd_size_type) 1);
 130
 131   gas_assert (x);
 132 }
 133
 134 static void
 135 obj_aout_line (int ignore ATTRIBUTE_UNUSED)
 136 {
 137   /* Assume delimiter is part of expression.
 138      BSD4.2 as fails with delightful bug, so we
 139      are not being incompatible here.  */
 140   new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
 141   demand_empty_rest_of_line ();
 142 }
 143
 144 /* Handle .weak.  This is a GNU extension.  */
 145
 146 static void
 147 obj_aout_weak (int ignore ATTRIBUTE_UNUSED)
 148 {
 149   char *name;
 150   int c;
 151   symbolS *symbolP;
 152
 153   do
 154     {
 155       c = get_symbol_name (&name);
 156       symbolP = symbol_find_or_make (name);
 157       (void) restore_line_pointer (c);
 158       SKIP_WHITESPACE ();
 159       S_SET_WEAK (symbolP);
 160       if (c == ',')
 161         {
 162           input_line_pointer++;
 163           SKIP_WHITESPACE ();
 164           if (*input_line_pointer == '\n')
 165             c = '\n';
 166         }
 167     }
 168   while (c == ',');
 169   demand_empty_rest_of_line ();
 170 }
 171
 172 /* Handle .type.  On {Net,Open}BSD, this is used to set the n_other field,
 173    which is then apparently used when doing dynamic linking.  Older
 174    versions of gas ignored the .type pseudo-op, so we also ignore it if
 175    we can't parse it.  */
 176
 177 static void
 178 obj_aout_type (int ignore ATTRIBUTE_UNUSED)
 179 {
 180   char *name;
 181   int c;
 182   symbolS *sym;
 183
 184   c = get_symbol_name (&name);
 185   sym = symbol_find_or_make (name);
 186   (void) restore_line_pointer (c);
 187   SKIP_WHITESPACE ();
 188   if (*input_line_pointer == ',')
 189     {
 190       ++input_line_pointer;
 191       SKIP_WHITESPACE ();
 192       if (*input_line_pointer == '@')
 193         {
 194           ++input_line_pointer;
 195           if (strncmp (input_line_pointer, "object", 6) == 0)
 196             S_SET_OTHER (sym, 1);
 197           else if (strncmp (input_line_pointer, "function", 8) == 0)
 198             S_SET_OTHER (sym, 2);
 199         }
 200     }
 201
 202   /* Ignore everything else on the line.  */
 203   s_ignore (0);
 204 }
 205
 206 /* Support for an AOUT emulation.  */
 207
 208 static void
 209 aout_pop_insert (void)
 210 {
 211   pop_insert (aout_pseudo_table);
 212 }
 213
 214 static int
 215 obj_aout_s_get_other (symbolS *sym)
 216 {
 217   return aout_symbol (symbol_get_bfdsym (sym))->other;
 218 }
 219
 220 static void
 221 obj_aout_s_set_other (symbolS *sym, int o)
 222 {
 223   aout_symbol (symbol_get_bfdsym (sym))->other = o;
 224 }
 225
 226 static int
 227 obj_aout_sec_sym_ok_for_reloc (asection *sec ATTRIBUTE_UNUSED)
 228 {
 229   return obj_sec_sym_ok_for_reloc (sec);
 230 }
 231
 232 static void
 233 obj_aout_process_stab (segT seg ATTRIBUTE_UNUSED,
 234                        int w,
 235                        const char *s,
 236                        int t,
 237                        int o,
 238                        int d)
 239 {
 240   aout_process_stab (w, s, t, o, d);
 241 }
 242
 243 static int
 244 obj_aout_s_get_desc (symbolS *sym)
 245 {
 246   return aout_symbol (symbol_get_bfdsym (sym))->desc;
 247 }
 248
 249 static void
 250 obj_aout_s_set_desc (symbolS *sym, int d)
 251 {
 252   aout_symbol (symbol_get_bfdsym (sym))->desc = d;
 253 }
 254
 255 static int
 256 obj_aout_s_get_type (symbolS *sym)
 257 {
 258   return aout_symbol (symbol_get_bfdsym (sym))->type;
 259 }
 260
 261 static void
 262 obj_aout_s_set_type (symbolS *sym, int t)
 263 {
 264   aout_symbol (symbol_get_bfdsym (sym))->type = t;
 265 }
 266
 267 static int
 268 obj_aout_separate_stab_sections (void)
 269 {
 270   return 0;
 271 }
 272
 273 /* When changed, make sure these table entries match the single-format
 274    definitions in obj-aout.h.  */
 275
 276 const struct format_ops aout_format_ops =
 277 {
 278   bfd_target_aout_flavour,
 279   1,    /* dfl_leading_underscore.  */
 280   0,    /* emit_section_symbols.  */
 281   0,    /* begin.  */
 282   0,    /* app_file.  */
 283   obj_aout_frob_symbol,
 284   0,    /* frob_file.  */
 285   0,    /* frob_file_before_adjust.  */
 286   obj_aout_frob_file_before_fix,
 287   0,    /* frob_file_after_relocs.  */
 288   0,    /* s_get_size.  */
 289   0,    /* s_set_size.  */
 290   0,    /* s_get_align.  */
 291   0,    /* s_set_align.  */
 292   obj_aout_s_get_other,
 293   obj_aout_s_set_other,
 294   obj_aout_s_get_desc,
 295   obj_aout_s_set_desc,
 296   obj_aout_s_get_type,
 297   obj_aout_s_set_type,
 298   0,    /* copy_symbol_attributes.  */
 299   0,    /* generate_asm_lineno.  */
 300   obj_aout_process_stab,
 301   obj_aout_separate_stab_sections,
 302   0,    /* init_stab_section.  */
 303   obj_aout_sec_sym_ok_for_reloc,
 304   aout_pop_insert,
 305   0,    /* ecoff_set_ext.  */
 306   0,    /* read_begin_hook.  */
 307   0,    /* symbol_new_hook.  */
 308   0,    /* symbol_clone_hook.  */
 309   0     /* adjust_symtab.  */
 310 };
 311
 312 const pseudo_typeS aout_pseudo_table[] =
 313 {
 314   {"line", obj_aout_line, 0},   /* Source code line number.  */
 315   {"ln", obj_aout_line, 0},     /* COFF line number that we use anyway.  */
 316
 317   {"weak", obj_aout_weak, 0},   /* Mark symbol as weak.  */
 318
 319   {"type", obj_aout_type, 0},
 320
 321   /* coff debug pseudos (ignored) */
 322   {"def", s_ignore, 0},
 323   {"dim", s_ignore, 0},
 324   {"endef", s_ignore, 0},
 325   {"ident", s_ignore, 0},
 326   {"line", s_ignore, 0},
 327   {"ln", s_ignore, 0},
 328   {"scl", s_ignore, 0},
 329   {"size", s_ignore, 0},
 330   {"tag", s_ignore, 0},
 331   {"val", s_ignore, 0},
 332   {"version", s_ignore, 0},
 333
 334   {"optim", s_ignore, 0},       /* For sun386i cc (?).  */
 335
 336   /* other stuff */
 337   {"ABORT", s_abort, 0},
 338
 339   {NULL, NULL, 0}
 340 };