obj-aout.c revision 60484
1/* a.out object file format 2 Copyright (C) 1989, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 2000 3 Free Software Foundation, Inc. 4 5This file is part of GAS, the GNU Assembler. 6 7GAS is free software; you can redistribute it and/or modify 8it under the terms of the GNU General Public License as 9published by the Free Software Foundation; either version 2, 10or (at your option) any later version. 11 12GAS is distributed in the hope that it will be useful, but 13WITHOUT ANY WARRANTY; without even the implied warranty of 14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 15the GNU General Public License for more details. 16 17You should have received a copy of the GNU General Public License 18along with GAS; see the file COPYING. If not, write to the Free 19Software Foundation, 59 Temple Place - Suite 330, Boston, MA 2002111-1307, USA. */ 21 22#define OBJ_HEADER "obj-aout.h" 23 24#include "as.h" 25#ifdef BFD_ASSEMBLER 26#undef NO_RELOC 27#include "aout/aout64.h" 28#endif 29#include "obstack.h" 30 31#ifndef BFD_ASSEMBLER 32/* in: segT out: N_TYPE bits */ 33const short seg_N_TYPE[] = 34{ 35 N_ABS, 36 N_TEXT, 37 N_DATA, 38 N_BSS, 39 N_UNDF, /* unknown */ 40 N_UNDF, /* error */ 41 N_UNDF, /* expression */ 42 N_UNDF, /* debug */ 43 N_UNDF, /* ntv */ 44 N_UNDF, /* ptv */ 45 N_REGISTER, /* register */ 46}; 47 48const segT N_TYPE_seg[N_TYPE + 2] = 49{ /* N_TYPE == 0x1E = 32-2 */ 50 SEG_UNKNOWN, /* N_UNDF == 0 */ 51 SEG_GOOF, 52 SEG_ABSOLUTE, /* N_ABS == 2 */ 53 SEG_GOOF, 54 SEG_TEXT, /* N_TEXT == 4 */ 55 SEG_GOOF, 56 SEG_DATA, /* N_DATA == 6 */ 57 SEG_GOOF, 58 SEG_BSS, /* N_BSS == 8 */ 59 SEG_GOOF, 60 SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, 61 SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, 62 SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, 63 SEG_REGISTER, /* dummy N_REGISTER for regs = 30 */ 64 SEG_GOOF, 65}; 66#endif 67 68static void obj_aout_line PARAMS ((int)); 69static void obj_aout_weak PARAMS ((int)); 70static void obj_aout_type PARAMS ((int)); 71 72const pseudo_typeS aout_pseudo_table[] = 73{ 74 {"line", obj_aout_line, 0}, /* source code line number */ 75 {"ln", obj_aout_line, 0}, /* coff line number that we use anyway */ 76 77 {"weak", obj_aout_weak, 0}, /* mark symbol as weak. */ 78 79 {"type", obj_aout_type, 0}, 80 81 /* coff debug pseudos (ignored) */ 82 {"def", s_ignore, 0}, 83 {"dim", s_ignore, 0}, 84 {"endef", s_ignore, 0}, 85 {"ident", s_ignore, 0}, 86 {"line", s_ignore, 0}, 87 {"ln", s_ignore, 0}, 88 {"scl", s_ignore, 0}, 89 {"size", s_ignore, 0}, 90 {"tag", s_ignore, 0}, 91 {"val", s_ignore, 0}, 92 {"version", s_ignore, 0}, 93 94 {"optim", s_ignore, 0}, /* For sun386i cc (?) */ 95 96 /* other stuff */ 97 {"ABORT", s_abort, 0}, 98 99 {NULL, NULL, 0} /* end sentinel */ 100}; /* aout_pseudo_table */ 101 102 103#ifdef BFD_ASSEMBLER 104 105void 106obj_aout_frob_symbol (sym, punt) 107 symbolS *sym; 108 int *punt; 109{ 110 flagword flags; 111 asection *sec; 112 int desc, type, other; 113 114 flags = symbol_get_bfdsym (sym)->flags; 115 desc = aout_symbol (symbol_get_bfdsym (sym))->desc; 116 type = aout_symbol (symbol_get_bfdsym (sym))->type; 117 other = aout_symbol (symbol_get_bfdsym (sym))->other; 118 sec = S_GET_SEGMENT (sym); 119 120 /* Only frob simple symbols this way right now. */ 121 if (! (type & ~ (N_TYPE | N_EXT))) 122 { 123 if (type == (N_UNDF | N_EXT) 124 && sec == &bfd_abs_section) 125 { 126 sec = bfd_und_section_ptr; 127 S_SET_SEGMENT (sym, sec); 128 } 129 130 if ((type & N_TYPE) != N_INDR 131 && (type & N_TYPE) != N_SETA 132 && (type & N_TYPE) != N_SETT 133 && (type & N_TYPE) != N_SETD 134 && (type & N_TYPE) != N_SETB 135 && type != N_WARNING 136 && (sec == &bfd_abs_section 137 || sec == &bfd_und_section)) 138 return; 139 if (flags & BSF_EXPORT) 140 type |= N_EXT; 141 142 switch (type & N_TYPE) 143 { 144 case N_SETA: 145 case N_SETT: 146 case N_SETD: 147 case N_SETB: 148 /* Set the debugging flag for constructor symbols so that 149 BFD leaves them alone. */ 150 symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING; 151 152 /* You can't put a common symbol in a set. The way a set 153 element works is that the symbol has a definition and a 154 name, and the linker adds the definition to the set of 155 that name. That does not work for a common symbol, 156 because the linker can't tell which common symbol the 157 user means. FIXME: Using as_bad here may be 158 inappropriate, since the user may want to force a 159 particular type without regard to the semantics of sets; 160 on the other hand, we certainly don't want anybody to be 161 mislead into thinking that their code will work. */ 162 if (S_IS_COMMON (sym)) 163 as_bad (_("Attempt to put a common symbol into set %s"), 164 S_GET_NAME (sym)); 165 /* Similarly, you can't put an undefined symbol in a set. */ 166 else if (! S_IS_DEFINED (sym)) 167 as_bad (_("Attempt to put an undefined symbol into set %s"), 168 S_GET_NAME (sym)); 169 170 break; 171 case N_INDR: 172 /* Put indirect symbols in the indirect section. */ 173 S_SET_SEGMENT (sym, bfd_ind_section_ptr); 174 symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT; 175 if (type & N_EXT) 176 { 177 symbol_get_bfdsym (sym)->flags |= BSF_EXPORT; 178 symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL; 179 } 180 break; 181 case N_WARNING: 182 /* Mark warning symbols. */ 183 symbol_get_bfdsym (sym)->flags |= BSF_WARNING; 184 break; 185 } 186 } 187 else 188 { 189 symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING; 190 } 191 192 aout_symbol (symbol_get_bfdsym (sym))->type = type; 193 194 /* Double check weak symbols. */ 195 if (S_IS_WEAK (sym)) 196 { 197 if (S_IS_COMMON (sym)) 198 as_bad (_("Symbol `%s' can not be both weak and common"), 199 S_GET_NAME (sym)); 200 } 201} 202 203void 204obj_aout_frob_file () 205{ 206 /* Relocation processing may require knowing the VMAs of the sections. 207 Since writing to a section will cause the BFD back end to compute the 208 VMAs, fake it out here.... */ 209 bfd_byte b = 0; 210 boolean x = true; 211 if (bfd_section_size (stdoutput, text_section) != 0) 212 { 213 x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0, 214 (bfd_size_type) 1); 215 } 216 else if (bfd_section_size (stdoutput, data_section) != 0) 217 { 218 x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0, 219 (bfd_size_type) 1); 220 } 221 assert (x == true); 222} 223 224#else /* ! BFD_ASSEMBLER */ 225 226/* Relocation. */ 227 228/* 229 * emit_relocations() 230 * 231 * Crawl along a fixS chain. Emit the segment's relocations. 232 */ 233void 234obj_emit_relocations (where, fixP, segment_address_in_file) 235 char **where; 236 fixS *fixP; /* Fixup chain for this segment. */ 237 relax_addressT segment_address_in_file; 238{ 239 for (; fixP; fixP = fixP->fx_next) 240 if (fixP->fx_done == 0) 241 { 242 symbolS *sym; 243 244 sym = fixP->fx_addsy; 245 while (sym->sy_value.X_op == O_symbol 246 && (! S_IS_DEFINED (sym) || S_IS_COMMON (sym))) 247 sym = sym->sy_value.X_add_symbol; 248 fixP->fx_addsy = sym; 249 250 if (! sym->sy_resolved && ! S_IS_DEFINED (sym)) 251 { 252 char *file; 253 unsigned int line; 254 255 if (expr_symbol_where (sym, &file, &line)) 256 as_bad_where (file, line, _("unresolved relocation")); 257 else 258 as_bad (_("bad relocation: symbol `%s' not in symbol table"), 259 S_GET_NAME (sym)); 260 } 261 262 tc_aout_fix_to_chars (*where, fixP, segment_address_in_file); 263 *where += md_reloc_size; 264 } 265} 266 267#ifndef obj_header_append 268/* Aout file generation & utilities */ 269void 270obj_header_append (where, headers) 271 char **where; 272 object_headers *headers; 273{ 274 tc_headers_hook (headers); 275 276#ifdef CROSS_COMPILE 277 md_number_to_chars (*where, headers->header.a_info, sizeof (headers->header.a_info)); 278 *where += sizeof (headers->header.a_info); 279 md_number_to_chars (*where, headers->header.a_text, sizeof (headers->header.a_text)); 280 *where += sizeof (headers->header.a_text); 281 md_number_to_chars (*where, headers->header.a_data, sizeof (headers->header.a_data)); 282 *where += sizeof (headers->header.a_data); 283 md_number_to_chars (*where, headers->header.a_bss, sizeof (headers->header.a_bss)); 284 *where += sizeof (headers->header.a_bss); 285 md_number_to_chars (*where, headers->header.a_syms, sizeof (headers->header.a_syms)); 286 *where += sizeof (headers->header.a_syms); 287 md_number_to_chars (*where, headers->header.a_entry, sizeof (headers->header.a_entry)); 288 *where += sizeof (headers->header.a_entry); 289 md_number_to_chars (*where, headers->header.a_trsize, sizeof (headers->header.a_trsize)); 290 *where += sizeof (headers->header.a_trsize); 291 md_number_to_chars (*where, headers->header.a_drsize, sizeof (headers->header.a_drsize)); 292 *where += sizeof (headers->header.a_drsize); 293 294#else /* CROSS_COMPILE */ 295 296 append (where, (char *) &headers->header, sizeof (headers->header)); 297#endif /* CROSS_COMPILE */ 298 299} 300#endif /* ! defined (obj_header_append) */ 301 302void 303obj_symbol_to_chars (where, symbolP) 304 char **where; 305 symbolS *symbolP; 306{ 307 md_number_to_chars ((char *) &(S_GET_OFFSET (symbolP)), S_GET_OFFSET (symbolP), sizeof (S_GET_OFFSET (symbolP))); 308 md_number_to_chars ((char *) &(S_GET_DESC (symbolP)), S_GET_DESC (symbolP), sizeof (S_GET_DESC (symbolP))); 309 md_number_to_chars ((char *) &(symbolP->sy_symbol.n_value), S_GET_VALUE (symbolP), sizeof (symbolP->sy_symbol.n_value)); 310 311 append (where, (char *) &symbolP->sy_symbol, sizeof (obj_symbol_type)); 312} 313 314void 315obj_emit_symbols (where, symbol_rootP) 316 char **where; 317 symbolS *symbol_rootP; 318{ 319 symbolS *symbolP; 320 321 /* Emit all symbols left in the symbol chain. */ 322 for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP)) 323 { 324 /* Used to save the offset of the name. It is used to point 325 to the string in memory but must be a file offset. */ 326 register char *temp; 327 328 temp = S_GET_NAME (symbolP); 329 S_SET_OFFSET (symbolP, symbolP->sy_name_offset); 330 331 /* Any symbol still undefined and is not a dbg symbol is made N_EXT. */ 332 if (!S_IS_DEBUG (symbolP) && !S_IS_DEFINED (symbolP)) 333 S_SET_EXTERNAL (symbolP); 334 335 /* Adjust the type of a weak symbol. */ 336 if (S_GET_WEAK (symbolP)) 337 { 338 switch (S_GET_TYPE (symbolP)) 339 { 340 case N_UNDF: S_SET_TYPE (symbolP, N_WEAKU); break; 341 case N_ABS: S_SET_TYPE (symbolP, N_WEAKA); break; 342 case N_TEXT: S_SET_TYPE (symbolP, N_WEAKT); break; 343 case N_DATA: S_SET_TYPE (symbolP, N_WEAKD); break; 344 case N_BSS: S_SET_TYPE (symbolP, N_WEAKB); break; 345 default: as_bad (_("%s: bad type for weak symbol"), temp); break; 346 } 347 } 348 349 obj_symbol_to_chars (where, symbolP); 350 S_SET_NAME (symbolP, temp); 351 } 352} 353 354#endif /* ! BFD_ASSEMBLER */ 355 356static void 357obj_aout_line (ignore) 358 int ignore; 359{ 360 /* Assume delimiter is part of expression. 361 BSD4.2 as fails with delightful bug, so we 362 are not being incompatible here. */ 363 new_logical_line ((char *) NULL, (int) (get_absolute_expression ())); 364 demand_empty_rest_of_line (); 365} /* obj_aout_line() */ 366 367/* Handle .weak. This is a GNU extension. */ 368 369static void 370obj_aout_weak (ignore) 371 int ignore; 372{ 373 char *name; 374 int c; 375 symbolS *symbolP; 376 377 do 378 { 379 name = input_line_pointer; 380 c = get_symbol_end (); 381 symbolP = symbol_find_or_make (name); 382 *input_line_pointer = c; 383 SKIP_WHITESPACE (); 384 S_SET_WEAK (symbolP); 385 if (c == ',') 386 { 387 input_line_pointer++; 388 SKIP_WHITESPACE (); 389 if (*input_line_pointer == '\n') 390 c = '\n'; 391 } 392 } 393 while (c == ','); 394 demand_empty_rest_of_line (); 395} 396 397/* Handle .type. On {Net,Open}BSD, this is used to set the n_other field, 398 which is then apparently used when doing dynamic linking. Older 399 versions ogas ignored the .type pseudo-op, so we also ignore it if 400 we can't parse it. */ 401 402static void 403obj_aout_type (ignore) 404 int ignore; 405{ 406 char *name; 407 int c; 408 symbolS *sym; 409 410 name = input_line_pointer; 411 c = get_symbol_end (); 412 sym = symbol_find (name); 413 *input_line_pointer = c; 414 if (sym != NULL) 415 { 416 SKIP_WHITESPACE (); 417 if (*input_line_pointer == ',') 418 { 419 ++input_line_pointer; 420 SKIP_WHITESPACE (); 421 if (*input_line_pointer == '@') 422 { 423 ++input_line_pointer; 424 if (strncmp (input_line_pointer, "object", 6) == 0) 425#ifdef BFD_ASSEMBLER 426 aout_symbol (symbol_get_bfdsym (sym))->other = 1; 427#else 428 S_SET_OTHER (sym, 1); 429#endif 430 else if (strncmp (input_line_pointer, "function", 8) == 0) 431#ifdef BFD_ASSEMBLER 432 aout_symbol (symbol_get_bfdsym (sym))->other = 2; 433#else 434 S_SET_OTHER (sym, 2); 435#endif 436 } 437 } 438 } 439 440 /* Ignore everything else on the line. */ 441 s_ignore (0); 442} 443 444#ifndef BFD_ASSEMBLER 445 446void 447obj_crawl_symbol_chain (headers) 448 object_headers *headers; 449{ 450 symbolS *symbolP; 451 symbolS **symbolPP; 452 int symbol_number = 0; 453 454 tc_crawl_symbol_chain (headers); 455 456 symbolPP = &symbol_rootP; /*->last symbol chain link. */ 457 while ((symbolP = *symbolPP) != NULL) 458 { 459 if (symbolP->sy_mri_common) 460 { 461 if (S_IS_EXTERNAL (symbolP)) 462 as_bad (_("%s: global symbols not supported in common sections"), 463 S_GET_NAME (symbolP)); 464 *symbolPP = symbol_next (symbolP); 465 continue; 466 } 467 468 if (flag_readonly_data_in_text && (S_GET_SEGMENT (symbolP) == SEG_DATA)) 469 { 470 S_SET_SEGMENT (symbolP, SEG_TEXT); 471 } /* if pusing data into text */ 472 473 resolve_symbol_value (symbolP, 1); 474 475 /* Skip symbols which were equated to undefined or common 476 symbols. */ 477 if (symbolP->sy_value.X_op == O_symbol 478 && (! S_IS_DEFINED (symbolP) || S_IS_COMMON (symbolP))) 479 { 480 *symbolPP = symbol_next (symbolP); 481 continue; 482 } 483 484 /* OK, here is how we decide which symbols go out into the brave 485 new symtab. Symbols that do are: 486 487 * symbols with no name (stabd's?) 488 * symbols with debug info in their N_TYPE 489 490 Symbols that don't are: 491 * symbols that are registers 492 * symbols with \1 as their 3rd character (numeric labels) 493 * "local labels" as defined by S_LOCAL_NAME(name) if the -L 494 switch was passed to gas. 495 496 All other symbols are output. We complain if a deleted 497 symbol was marked external. */ 498 499 500 if (!S_IS_REGISTER (symbolP) 501 && (!S_GET_NAME (symbolP) 502 || S_IS_DEBUG (symbolP) 503 || !S_IS_DEFINED (symbolP) 504 || S_IS_EXTERNAL (symbolP) 505 || (S_GET_NAME (symbolP)[0] != '\001' 506 && (flag_keep_locals || !S_LOCAL_NAME (symbolP))))) 507 { 508 symbolP->sy_number = symbol_number++; 509 510 /* The + 1 after strlen account for the \0 at the 511 end of each string */ 512 if (!S_IS_STABD (symbolP)) 513 { 514 /* Ordinary case. */ 515 symbolP->sy_name_offset = string_byte_count; 516 string_byte_count += strlen (S_GET_NAME (symbolP)) + 1; 517 } 518 else /* .Stabd case. */ 519 symbolP->sy_name_offset = 0; 520 symbolPP = &symbolP->sy_next; 521 } 522 else 523 { 524 if (S_IS_EXTERNAL (symbolP) || !S_IS_DEFINED (symbolP)) 525 /* This warning should never get triggered any more. 526 Well, maybe if you're doing twisted things with 527 register names... */ 528 { 529 as_bad (_("Local symbol %s never defined."), decode_local_label_name (S_GET_NAME (symbolP))); 530 } /* oops. */ 531 532 /* Unhook it from the chain */ 533 *symbolPP = symbol_next (symbolP); 534 } /* if this symbol should be in the output */ 535 } /* for each symbol */ 536 537 H_SET_SYMBOL_TABLE_SIZE (headers, symbol_number); 538} 539 540/* 541 * Find strings by crawling along symbol table chain. 542 */ 543 544void 545obj_emit_strings (where) 546 char **where; 547{ 548 symbolS *symbolP; 549 550#ifdef CROSS_COMPILE 551 /* Gotta do md_ byte-ordering stuff for string_byte_count first - KWK */ 552 md_number_to_chars (*where, string_byte_count, sizeof (string_byte_count)); 553 *where += sizeof (string_byte_count); 554#else /* CROSS_COMPILE */ 555 append (where, (char *) &string_byte_count, (unsigned long) sizeof (string_byte_count)); 556#endif /* CROSS_COMPILE */ 557 558 for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP)) 559 { 560 if (S_GET_NAME (symbolP)) 561 append (&next_object_file_charP, S_GET_NAME (symbolP), 562 (unsigned long) (strlen (S_GET_NAME (symbolP)) + 1)); 563 } /* walk symbol chain */ 564} 565 566#ifndef AOUT_VERSION 567#define AOUT_VERSION 0 568#endif 569 570void 571obj_pre_write_hook (headers) 572 object_headers *headers; 573{ 574 H_SET_DYNAMIC (headers, 0); 575 H_SET_VERSION (headers, AOUT_VERSION); 576 H_SET_MACHTYPE (headers, AOUT_MACHTYPE); 577 tc_aout_pre_write_hook (headers); 578} 579 580void 581DEFUN_VOID (s_sect) 582{ 583 /* Strip out the section name */ 584 char *section_name; 585 char *section_name_end; 586 char c; 587 588 unsigned int len; 589 unsigned int exp; 590 char *save; 591 592 section_name = input_line_pointer; 593 c = get_symbol_end (); 594 section_name_end = input_line_pointer; 595 596 len = section_name_end - section_name; 597 input_line_pointer++; 598 save = input_line_pointer; 599 600 SKIP_WHITESPACE (); 601 if (c == ',') 602 { 603 exp = get_absolute_expression (); 604 } 605 else if (*input_line_pointer == ',') 606 { 607 input_line_pointer++; 608 exp = get_absolute_expression (); 609 } 610 else 611 { 612 input_line_pointer = save; 613 exp = 0; 614 } 615 if (exp >= 1000) 616 { 617 as_bad (_("subsegment index too high")); 618 } 619 620 if (strcmp (section_name, ".text") == 0) 621 { 622 subseg_set (SEG_TEXT, (subsegT) exp); 623 } 624 625 if (strcmp (section_name, ".data") == 0) 626 { 627 if (flag_readonly_data_in_text) 628 subseg_set (SEG_TEXT, (subsegT) exp + 1000); 629 else 630 subseg_set (SEG_DATA, (subsegT) exp); 631 } 632 633 *section_name_end = c; 634} 635 636#endif /* ! BFD_ASSEMBLER */ 637 638#ifdef BFD_ASSEMBLER 639 640/* Support for an AOUT emulation. */ 641 642static void aout_pop_insert PARAMS ((void)); 643static int obj_aout_s_get_other PARAMS ((symbolS *)); 644static int obj_aout_s_get_desc PARAMS ((symbolS *)); 645 646static void 647aout_pop_insert () 648{ 649 pop_insert (aout_pseudo_table); 650} 651 652static int 653obj_aout_s_get_other (sym) 654 symbolS *sym; 655{ 656 return aout_symbol (symbol_get_bfdsym (sym))->other; 657} 658 659static int 660obj_aout_s_get_desc (sym) 661 symbolS *sym; 662{ 663 return aout_symbol (symbol_get_bfdsym (sym))->desc; 664} 665 666 667const struct format_ops aout_format_ops = 668{ 669 bfd_target_aout_flavour, 670 1, /* dfl_leading_underscore */ 671 0, /* emit_section_symbols */ 672 obj_aout_frob_symbol, 673 obj_aout_frob_file, 674 0, /* frob_file_after_relocs */ 675 0, /* s_get_size */ 676 0, /* s_set_size */ 677 0, /* s_get_align */ 678 0, /* s_set_align */ 679 obj_aout_s_get_other, 680 obj_aout_s_get_desc, 681 0, /* copy_symbol_attributes */ 682 0, /* generate_asm_lineno */ 683 0, /* process_stab */ 684 0, /* sec_sym_ok_for_reloc */ 685 aout_pop_insert, 686 0, /* ecoff_set_ext */ 687 0, /* read_begin_hook */ 688 0 /* symbol_new_hook */ 689}; 690#endif BFD_ASSEMBLER 691 692/* end of obj-aout.c */ 693