gas/config/obj-bout.c

   1 /* b.out object file format
   2    Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1996, 2000, 2001, 2002,
   3    2003, 2005 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 2,
  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 #include "as.h"
  23 #include "obstack.h"
  24
  25 /* In: segT   Out: N_TYPE bits.  */
  26 const short seg_N_TYPE[] =
  27 {
  28   N_ABS,
  29   N_TEXT,
  30   N_DATA,
  31   N_BSS,
  32   N_UNDF,                       /* Unknown.  */
  33   N_UNDF,                       /* Error.  */
  34   N_UNDF,                       /* Expression.  */
  35   N_UNDF,                       /* Debug.  */
  36   N_UNDF,                       /* Ntv.  */
  37   N_UNDF,                       /* Ptv.  */
  38   N_REGISTER,                   /* Register.  */
  39 };
  40
  41 const segT N_TYPE_seg[N_TYPE + 2] =
  42 {                               /* N_TYPE == 0x1E = 32-2  */
  43   SEG_UNKNOWN,                  /* N_UNDF == 0  */
  44   SEG_GOOF,
  45   SEG_ABSOLUTE,                 /* N_ABS == 2  */
  46   SEG_GOOF,
  47   SEG_TEXT,                     /* N_TEXT == 4  */
  48   SEG_GOOF,
  49   SEG_DATA,                     /* N_DATA == 6  */
  50   SEG_GOOF,
  51   SEG_BSS,                      /* N_BSS == 8  */
  52   SEG_GOOF,
  53   SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
  54   SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
  55   SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
  56   SEG_REGISTER,                 /* Dummy N_REGISTER for regs = 30.   */
  57   SEG_GOOF,
  58 };
  59
  60 /* Relocation.  */
  61
  62 /* Crawl along a fixS chain. Emit the segment's relocations.  */
  63
  64 void
  65 obj_emit_relocations (char **where,
  66                       fixS *fixP,               /* Fixup chain for this segment.  */
  67                       relax_addressT segment_address_in_file)
  68 {
  69   for (; fixP; fixP = fixP->fx_next)
  70     {
  71       if (fixP->fx_done == 0
  72           || fixP->fx_r_type != NO_RELOC)
  73         {
  74           symbolS *sym;
  75
  76           sym = fixP->fx_addsy;
  77           while (sym->sy_value.X_op == O_symbol
  78                  && (! S_IS_DEFINED (sym) || S_IS_COMMON (sym)))
  79             sym = sym->sy_value.X_add_symbol;
  80           fixP->fx_addsy = sym;
  81
  82           tc_bout_fix_to_chars (*where, fixP, segment_address_in_file);
  83           *where += md_reloc_size;
  84         }
  85     }
  86 }
  87
  88 /* Aout file generation & utilities .  */
  89
  90 /* Convert a lvalue to machine dependent data.  */
  91
  92 void
  93 obj_header_append (char **where, object_headers *headers)
  94 {
  95   /* Always leave in host byte order.  */
  96   char *p;
  97
  98   headers->header.a_talign = section_alignment[SEG_TEXT];
  99
 100   /* Force to at least 2.  */
 101   if (headers->header.a_talign < 2)
 102     headers->header.a_talign = 2;
 103
 104   headers->header.a_dalign = section_alignment[SEG_DATA];
 105   headers->header.a_balign = section_alignment[SEG_BSS];
 106
 107   headers->header.a_tload = 0;
 108   headers->header.a_dload =
 109     md_section_align (SEG_DATA, H_GET_TEXT_SIZE (headers));
 110
 111   headers->header.a_relaxable = linkrelax;
 112
 113   p = *where;
 114   host_number_to_chars (p, headers->header.a_magic, 4);
 115   p += 4;
 116   host_number_to_chars (p, headers->header.a_text, 4);
 117   p += 4;
 118   host_number_to_chars (p, headers->header.a_data, 4);
 119   p += 4;
 120   host_number_to_chars (p, headers->header.a_bss, 4);
 121   p += 4;
 122   host_number_to_chars (p, headers->header.a_syms, 4);
 123   p += 4;
 124   host_number_to_chars (p, headers->header.a_entry, 4);
 125   p += 4;
 126   host_number_to_chars (p, headers->header.a_trsize, 4);
 127   p += 4;
 128   host_number_to_chars (p, headers->header.a_drsize, 4);
 129   p += 4;
 130   host_number_to_chars (p, headers->header.a_tload, 4);
 131   p += 4;
 132   host_number_to_chars (p, headers->header.a_dload, 4);
 133   p += 4;
 134   *p++ = headers->header.a_talign;
 135   *p++ = headers->header.a_dalign;
 136   *p++ = headers->header.a_balign;
 137   *p++ = headers->header.a_relaxable;
 138   *where = p;
 139 }
 140
 141 void
 142 obj_symbol_to_chars (char **where, symbolS *symbolP)
 143 {
 144   char *p = *where;
 145
 146   host_number_to_chars (p, S_GET_OFFSET (symbolP), 4);
 147   p += 4;
 148   /* Can't use S_GET_TYPE here as it masks.  */
 149   *p++ = symbolP->sy_symbol.n_type;
 150   *p++ = symbolP->sy_symbol.n_other;
 151   host_number_to_chars (p, S_GET_DESC (symbolP), 2);
 152   p += 2;
 153   host_number_to_chars (p, S_GET_VALUE (symbolP), 4);
 154   p += 4;
 155   *where = p;
 156 }
 157
 158 void
 159 obj_emit_symbols (char **where, symbolS *symbol_rootP)
 160 {
 161   symbolS *symbolP;
 162
 163   /* Emit all symbols left in the symbol chain.  */
 164   for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP))
 165     {
 166       /* Used to save the offset of the name.  It is used to point to
 167          the string in memory but must be a file offset.  */
 168       char *temp;
 169
 170       temp = S_GET_NAME (symbolP);
 171       S_SET_OFFSET (symbolP, symbolP->sy_name_offset);
 172
 173       /* Any symbol still undefined and is not a dbg symbol is made N_EXT.  */
 174       if (!S_IS_DEBUG (symbolP) && !S_IS_DEFINED (symbolP))
 175         S_SET_EXTERNAL (symbolP);
 176
 177       obj_symbol_to_chars (where, symbolP);
 178       S_SET_NAME (symbolP, temp);
 179     }
 180 }
 181
 182 void
 183 obj_symbol_new_hook (symbolS *symbolP)
 184 {
 185   S_SET_OTHER (symbolP, 0);
 186   S_SET_DESC (symbolP, 0);
 187 }
 188
 189 static void
 190 obj_bout_line (int ignore ATTRIBUTE_UNUSED)
 191 {
 192   /* Assume delimiter is part of expression.  */
 193   /* BSD4.2 as fails with delightful bug, so we are not being
 194      incompatible here.  */
 195   new_logical_line (NULL, (int) (get_absolute_expression ()));
 196   demand_empty_rest_of_line ();
 197 }
 198
 199 void
 200 obj_read_begin_hook (void)
 201 {
 202 }
 203
 204 void
 205 obj_crawl_symbol_chain (object_headers *headers)
 206 {
 207   symbolS **symbolPP;
 208   symbolS *symbolP;
 209   int symbol_number = 0;
 210
 211   tc_crawl_symbol_chain (headers);
 212
 213   symbolPP = &symbol_rootP;     /* -> last symbol chain link.  */
 214   while ((symbolP = *symbolPP) != NULL)
 215     {
 216       if (flag_readonly_data_in_text && (S_GET_SEGMENT (symbolP) == SEG_DATA))
 217         {
 218           S_SET_SEGMENT (symbolP, SEG_TEXT);
 219         }
 220
 221       resolve_symbol_value (symbolP);
 222
 223       /* Skip symbols which were equated to undefined or common
 224          symbols.  */
 225       if (symbolP->sy_value.X_op == O_symbol
 226           && (! S_IS_DEFINED (symbolP) || S_IS_COMMON (symbolP)))
 227         {
 228           *symbolPP = symbol_next (symbolP);
 229           continue;
 230         }
 231
 232       /* OK, here is how we decide which symbols go out into the
 233          brave new symtab.  Symbols that do are:
 234
 235          * symbols with no name (stabd's?)
 236          * symbols with debug info in their N_TYPE
 237
 238          Symbols that don't are:
 239          * symbols that are registers
 240          * symbols with \1 as their 3rd character (numeric labels)
 241          * "local labels" as defined by S_LOCAL_NAME(name)
 242          if the -L switch was passed to gas.
 243
 244          All other symbols are output.  We complain if a deleted
 245          symbol was marked external.  */
 246
 247       if (1
 248           && !S_IS_REGISTER (symbolP)
 249           && (!S_GET_NAME (symbolP)
 250               || S_IS_DEBUG (symbolP)
 251 #ifdef TC_I960
 252       /* FIXME-SOON this ifdef seems highly dubious to me.  xoxorich.  */
 253               || !S_IS_DEFINED (symbolP)
 254               || S_IS_EXTERNAL (symbolP)
 255 #endif
 256               || (S_GET_NAME (symbolP)[0] != '\001'
 257                   && (flag_keep_locals || !S_LOCAL_NAME (symbolP)))))
 258         {
 259           symbolP->sy_number = symbol_number++;
 260
 261           /* The + 1 after strlen account for the \0 at the end of
 262              each string.  */
 263           if (!S_IS_STABD (symbolP))
 264             {
 265               /* Ordinary case.  */
 266               symbolP->sy_name_offset = string_byte_count;
 267               string_byte_count += strlen (S_GET_NAME (symbolP)) + 1;
 268             }
 269           else                  /* .Stabd case.  */
 270             symbolP->sy_name_offset = 0;
 271           symbolPP = &(symbolP->sy_next);
 272         }
 273       else
 274         {
 275           if (S_IS_EXTERNAL (symbolP) || !S_IS_DEFINED (symbolP))
 276             as_bad (_("Local symbol %s never defined"),
 277                     S_GET_NAME (symbolP));
 278
 279           /* Unhook it from the chain.  */
 280           *symbolPP = symbol_next (symbolP);
 281         }
 282     }
 283
 284   H_SET_SYMBOL_TABLE_SIZE (headers, symbol_number);
 285 }
 286
 287 /* Find strings by crawling along symbol table chain.  */
 288
 289 void
 290 obj_emit_strings (char **where)
 291 {
 292   symbolS *symbolP;
 293
 294   md_number_to_chars (*where, string_byte_count, 4);
 295   *where += 4;
 296
 297   for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP))
 298     if (S_GET_NAME (symbolP))
 299       append (where, S_GET_NAME (symbolP),
 300               (unsigned long) (strlen (S_GET_NAME (symbolP)) + 1));
 301 }
 302
 303 const pseudo_typeS obj_pseudo_table[] =
 304 {
 305   {"line", obj_bout_line, 0},   /* Source code line number.  */
 306
 307   /* COFF debugging directives.  Currently ignored silently.  */
 308   {"def", s_ignore, 0},
 309   {"dim", s_ignore, 0},
 310   {"endef", s_ignore, 0},
 311   {"ln", s_ignore, 0},
 312   {"scl", s_ignore, 0},
 313   {"size", s_ignore, 0},
 314   {"tag", s_ignore, 0},
 315   {"type", s_ignore, 0},
 316   {"val", s_ignore, 0},
 317
 318   /* Other stuff we don't handle.  */
 319   {"ABORT", s_ignore, 0},
 320   {"ident", s_ignore, 0},
 321
 322   {NULL, NULL, 0}
 323 };
 324