1 /* a.out object file format 2 Copyright (C) 1989-2020 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 }; 351