1 /* Generic stabs parsing for gas. 2 Copyright 1989, 1990, 1991, 1993, 1995, 1996, 1997, 1998, 2000, 2001 3 2002, 2003, 2004, 2005, 2007, 2009 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 3, 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 #include "subsegs.h" 25 #include "ecoff.h" 26 27 /* We need this, despite the apparent object format dependency, since 28 it defines stab types, which all object formats can use now. */ 29 30 #include "aout/stab_gnu.h" 31 32 /* Holds whether the assembler is generating stabs line debugging 33 information or not. Potentially used by md_cleanup function. */ 34 35 int outputting_stabs_line_debug = 0; 36 37 static void s_stab_generic (int, char *, char *); 38 static void generate_asm_file (int, char *); 39 40 /* Allow backends to override the names used for the stab sections. */ 41 #ifndef STAB_SECTION_NAME 42 #define STAB_SECTION_NAME ".stab" 43 #endif 44 45 #ifndef STAB_STRING_SECTION_NAME 46 #define STAB_STRING_SECTION_NAME ".stabstr" 47 #endif 48 49 /* Non-zero if we're in the middle of a .func function, in which case 50 stabs_generate_asm_lineno emits function relative line number stabs. 51 Otherwise it emits line number stabs with absolute addresses. Note that 52 both cases only apply to assembler code assembled with -gstabs. */ 53 static int in_dot_func_p; 54 55 /* Label at start of current function if in_dot_func_p != 0. */ 56 static const char *current_function_label; 57 58 /* 59 * Handle .stabX directives, which used to be open-coded. 60 * So much creeping featurism overloaded the semantics that we decided 61 * to put all .stabX thinking in one place. Here. 62 * 63 * We try to make any .stabX directive legal. Other people's AS will often 64 * do assembly-time consistency checks: eg assigning meaning to n_type bits 65 * and "protecting" you from setting them to certain values. (They also zero 66 * certain bits before emitting symbols. Tut tut.) 67 * 68 * If an expression is not absolute we either gripe or use the relocation 69 * information. Other people's assemblers silently forget information they 70 * don't need and invent information they need that you didn't supply. 71 */ 72 73 /* 74 * Build a string dictionary entry for a .stabX symbol. 75 * The symbol is added to the .<secname>str section. 76 */ 77 78 #ifndef SEPARATE_STAB_SECTIONS 79 #define SEPARATE_STAB_SECTIONS 0 80 #endif 81 82 unsigned int 83 get_stab_string_offset (const char *string, const char *stabstr_secname) 84 { 85 unsigned int length; 86 unsigned int retval; 87 segT save_seg; 88 subsegT save_subseg; 89 segT seg; 90 char *p; 91 92 if (! SEPARATE_STAB_SECTIONS) 93 abort (); 94 95 length = strlen (string); 96 97 save_seg = now_seg; 98 save_subseg = now_subseg; 99 100 /* Create the stab string section. */ 101 seg = subseg_new (stabstr_secname, 0); 102 103 retval = seg_info (seg)->stabu.stab_string_size; 104 if (retval <= 0) 105 { 106 /* Make sure the first string is empty. */ 107 p = frag_more (1); 108 *p = 0; 109 retval = seg_info (seg)->stabu.stab_string_size = 1; 110 bfd_set_section_flags (stdoutput, seg, SEC_READONLY | SEC_DEBUGGING); 111 if (seg->name == stabstr_secname) 112 seg->name = xstrdup (stabstr_secname); 113 } 114 115 if (length > 0) 116 { /* Ordinary case. */ 117 p = frag_more (length + 1); 118 strcpy (p, string); 119 120 seg_info (seg)->stabu.stab_string_size += length + 1; 121 } 122 else 123 retval = 0; 124 125 subseg_set (save_seg, save_subseg); 126 127 return retval; 128 } 129 130 #ifdef AOUT_STABS 131 #ifndef OBJ_PROCESS_STAB 132 #define OBJ_PROCESS_STAB(SEG,W,S,T,O,D) aout_process_stab(W,S,T,O,D) 133 #endif 134 135 /* Here instead of obj-aout.c because other formats use it too. */ 136 void 137 aout_process_stab (what, string, type, other, desc) 138 int what; 139 const char *string; 140 int type, other, desc; 141 { 142 /* Put the stab information in the symbol table. */ 143 symbolS *symbol; 144 145 /* Create the symbol now, but only insert it into the symbol chain 146 after any symbols mentioned in the value expression get into the 147 symbol chain. This is to avoid "continuation symbols" (where one 148 ends in "\" and the debug info is continued in the next .stabs 149 directive) from being separated by other random symbols. */ 150 symbol = symbol_create (string, undefined_section, 0, 151 &zero_address_frag); 152 if (what == 's' || what == 'n') 153 { 154 /* Pick up the value from the input line. */ 155 pseudo_set (symbol); 156 } 157 else 158 { 159 /* .stabd sets the name to NULL. Why? */ 160 S_SET_NAME (symbol, NULL); 161 symbol_set_frag (symbol, frag_now); 162 S_SET_VALUE (symbol, (valueT) frag_now_fix ()); 163 } 164 165 symbol_append (symbol, symbol_lastP, &symbol_rootP, &symbol_lastP); 166 167 symbol_get_bfdsym (symbol)->flags |= BSF_DEBUGGING; 168 169 S_SET_TYPE (symbol, type); 170 S_SET_OTHER (symbol, other); 171 S_SET_DESC (symbol, desc); 172 } 173 #endif 174 175 /* This can handle different kinds of stabs (s,n,d) and different 176 kinds of stab sections. */ 177 178 static void 179 s_stab_generic (int what, char *stab_secname, char *stabstr_secname) 180 { 181 long longint; 182 char *string, *saved_string_obstack_end; 183 int type; 184 int other; 185 int desc; 186 187 /* The general format is: 188 .stabs "STRING",TYPE,OTHER,DESC,VALUE 189 .stabn TYPE,OTHER,DESC,VALUE 190 .stabd TYPE,OTHER,DESC 191 At this point input_line_pointer points after the pseudo-op and 192 any trailing whitespace. The argument what is one of 's', 'n' or 193 'd' indicating which type of .stab this is. */ 194 195 if (what != 's') 196 { 197 string = ""; 198 saved_string_obstack_end = 0; 199 } 200 else 201 { 202 int length; 203 204 string = demand_copy_C_string (&length); 205 /* FIXME: We should probably find some other temporary storage 206 for string, rather than leaking memory if someone else 207 happens to use the notes obstack. */ 208 saved_string_obstack_end = notes.next_free; 209 SKIP_WHITESPACE (); 210 if (*input_line_pointer == ',') 211 input_line_pointer++; 212 else 213 { 214 as_warn (_(".stab%c: missing comma"), what); 215 ignore_rest_of_line (); 216 return; 217 } 218 } 219 220 if (get_absolute_expression_and_terminator (&longint) != ',') 221 { 222 as_warn (_(".stab%c: missing comma"), what); 223 ignore_rest_of_line (); 224 return; 225 } 226 type = longint; 227 228 if (get_absolute_expression_and_terminator (&longint) != ',') 229 { 230 as_warn (_(".stab%c: missing comma"), what); 231 ignore_rest_of_line (); 232 return; 233 } 234 other = longint; 235 236 desc = get_absolute_expression (); 237 238 if ((desc > 0xffff) || (desc < -0x8000)) 239 /* This could happen for example with a source file with a huge 240 number of lines. The only cure is to use a different debug 241 format, probably DWARF. */ 242 as_warn (_(".stab%c: description field '%x' too big, try a different debug format"), 243 what, desc); 244 245 if (what == 's' || what == 'n') 246 { 247 if (*input_line_pointer != ',') 248 { 249 as_warn (_(".stab%c: missing comma"), what); 250 ignore_rest_of_line (); 251 return; 252 } 253 input_line_pointer++; 254 SKIP_WHITESPACE (); 255 } 256 257 #ifdef TC_PPC 258 #ifdef OBJ_ELF 259 /* Solaris on PowerPC has decided that .stabd can take 4 arguments, so if we were 260 given 4 arguments, make it a .stabn */ 261 else if (what == 'd') 262 { 263 char *save_location = input_line_pointer; 264 265 SKIP_WHITESPACE (); 266 if (*input_line_pointer == ',') 267 { 268 input_line_pointer++; 269 what = 'n'; 270 } 271 else 272 input_line_pointer = save_location; 273 } 274 #endif /* OBJ_ELF */ 275 #endif /* TC_PPC */ 276 277 #ifndef NO_LISTING 278 if (listing) 279 { 280 switch (type) 281 { 282 case N_SLINE: 283 listing_source_line ((unsigned int) desc); 284 break; 285 case N_SO: 286 case N_SOL: 287 listing_source_file (string); 288 break; 289 } 290 } 291 #endif /* ! NO_LISTING */ 292 293 /* We have now gathered the type, other, and desc information. For 294 .stabs or .stabn, input_line_pointer is now pointing at the 295 value. */ 296 297 if (SEPARATE_STAB_SECTIONS) 298 /* Output the stab information in a separate section. This is used 299 at least for COFF and ELF. */ 300 { 301 segT saved_seg = now_seg; 302 subsegT saved_subseg = now_subseg; 303 fragS *saved_frag = frag_now; 304 valueT dot; 305 segT seg; 306 unsigned int stroff; 307 char *p; 308 309 static segT cached_sec; 310 static char *cached_secname; 311 312 dot = frag_now_fix (); 313 314 #ifdef md_flush_pending_output 315 md_flush_pending_output (); 316 #endif 317 318 if (cached_secname && !strcmp (cached_secname, stab_secname)) 319 { 320 seg = cached_sec; 321 subseg_set (seg, 0); 322 } 323 else 324 { 325 seg = subseg_new (stab_secname, 0); 326 if (cached_secname) 327 free (cached_secname); 328 cached_secname = xstrdup (stab_secname); 329 cached_sec = seg; 330 } 331 332 if (! seg_info (seg)->hadone) 333 { 334 bfd_set_section_flags (stdoutput, seg, 335 SEC_READONLY | SEC_RELOC | SEC_DEBUGGING); 336 #ifdef INIT_STAB_SECTION 337 INIT_STAB_SECTION (seg); 338 #endif 339 seg_info (seg)->hadone = 1; 340 } 341 342 stroff = get_stab_string_offset (string, stabstr_secname); 343 if (what == 's') 344 { 345 /* Release the string, if nobody else has used the obstack. */ 346 if (saved_string_obstack_end == notes.next_free) 347 obstack_free (¬es, string); 348 } 349 350 /* At least for now, stabs in a special stab section are always 351 output as 12 byte blocks of information. */ 352 p = frag_more (8); 353 md_number_to_chars (p, (valueT) stroff, 4); 354 md_number_to_chars (p + 4, (valueT) type, 1); 355 md_number_to_chars (p + 5, (valueT) other, 1); 356 md_number_to_chars (p + 6, (valueT) desc, 2); 357 358 if (what == 's' || what == 'n') 359 { 360 /* Pick up the value from the input line. */ 361 cons (4); 362 input_line_pointer--; 363 } 364 else 365 { 366 symbolS *symbol; 367 expressionS exp; 368 369 /* Arrange for a value representing the current location. */ 370 symbol = symbol_temp_new (saved_seg, dot, saved_frag); 371 372 exp.X_op = O_symbol; 373 exp.X_add_symbol = symbol; 374 exp.X_add_number = 0; 375 376 emit_expr (&exp, 4); 377 } 378 379 #ifdef OBJ_PROCESS_STAB 380 OBJ_PROCESS_STAB (seg, what, string, type, other, desc); 381 #endif 382 383 subseg_set (saved_seg, saved_subseg); 384 } 385 else 386 { 387 #ifdef OBJ_PROCESS_STAB 388 OBJ_PROCESS_STAB (0, what, string, type, other, desc); 389 #else 390 abort (); 391 #endif 392 } 393 394 demand_empty_rest_of_line (); 395 } 396 397 /* Regular stab directive. */ 398 399 void 400 s_stab (int what) 401 { 402 s_stab_generic (what, STAB_SECTION_NAME, STAB_STRING_SECTION_NAME); 403 } 404 405 /* "Extended stabs", used in Solaris only now. */ 406 407 void 408 s_xstab (int what) 409 { 410 int length; 411 char *stab_secname, *stabstr_secname; 412 static char *saved_secname, *saved_strsecname; 413 414 /* @@ MEMORY LEAK: This allocates a copy of the string, but in most 415 cases it will be the same string, so we could release the storage 416 back to the obstack it came from. */ 417 stab_secname = demand_copy_C_string (&length); 418 SKIP_WHITESPACE (); 419 if (*input_line_pointer == ',') 420 input_line_pointer++; 421 else 422 { 423 as_bad (_("comma missing in .xstabs")); 424 ignore_rest_of_line (); 425 return; 426 } 427 428 /* To get the name of the stab string section, simply add "str" to 429 the stab section name. */ 430 if (saved_secname == 0 || strcmp (saved_secname, stab_secname)) 431 { 432 stabstr_secname = (char *) xmalloc (strlen (stab_secname) + 4); 433 strcpy (stabstr_secname, stab_secname); 434 strcat (stabstr_secname, "str"); 435 if (saved_secname) 436 { 437 free (saved_secname); 438 free (saved_strsecname); 439 } 440 saved_secname = stab_secname; 441 saved_strsecname = stabstr_secname; 442 } 443 s_stab_generic (what, saved_secname, saved_strsecname); 444 } 445 446 #ifdef S_SET_DESC 447 448 /* Frob invented at RMS' request. Set the n_desc of a symbol. */ 449 450 void 451 s_desc (ignore) 452 int ignore ATTRIBUTE_UNUSED; 453 { 454 char *name; 455 char c; 456 char *p; 457 symbolS *symbolP; 458 int temp; 459 460 name = input_line_pointer; 461 c = get_symbol_end (); 462 p = input_line_pointer; 463 *p = c; 464 SKIP_WHITESPACE (); 465 if (*input_line_pointer != ',') 466 { 467 *p = 0; 468 as_bad (_("expected comma after \"%s\""), name); 469 *p = c; 470 ignore_rest_of_line (); 471 } 472 else 473 { 474 input_line_pointer++; 475 temp = get_absolute_expression (); 476 *p = 0; 477 symbolP = symbol_find_or_make (name); 478 *p = c; 479 S_SET_DESC (symbolP, temp); 480 } 481 demand_empty_rest_of_line (); 482 } /* s_desc() */ 483 484 #endif /* defined (S_SET_DESC) */ 485 486 /* Generate stabs debugging information to denote the main source file. */ 487 488 void 489 stabs_generate_asm_file (void) 490 { 491 char *file; 492 unsigned int lineno; 493 494 as_where (&file, &lineno); 495 if (use_gnu_debug_info_extensions) 496 { 497 const char *dir; 498 char *dir2; 499 500 dir = remap_debug_filename (getpwd ()); 501 dir2 = (char *) alloca (strlen (dir) + 2); 502 sprintf (dir2, "%s%s", dir, "/"); 503 generate_asm_file (N_SO, dir2); 504 } 505 generate_asm_file (N_SO, file); 506 } 507 508 /* Generate stabs debugging information to denote the source file. 509 TYPE is one of N_SO, N_SOL. */ 510 511 static void 512 generate_asm_file (int type, char *file) 513 { 514 static char *last_file; 515 static int label_count; 516 char *hold; 517 char sym[30]; 518 char *buf; 519 char *tmp = file; 520 char *file_endp = file + strlen (file); 521 char *bufp; 522 523 if (last_file != NULL 524 && strcmp (last_file, file) == 0) 525 return; 526 527 /* Rather than try to do this in some efficient fashion, we just 528 generate a string and then parse it again. That lets us use the 529 existing stabs hook, which expect to see a string, rather than 530 inventing new ones. */ 531 hold = input_line_pointer; 532 533 sprintf (sym, "%sF%d", FAKE_LABEL_NAME, label_count); 534 ++label_count; 535 536 /* Allocate enough space for the file name (possibly extended with 537 doubled up backslashes), the symbol name, and the other characters 538 that make up a stabs file directive. */ 539 bufp = buf = (char *) xmalloc (2 * strlen (file) + strlen (sym) + 12); 540 541 *bufp++ = '"'; 542 543 while (tmp < file_endp) 544 { 545 char *bslash = strchr (tmp, '\\'); 546 size_t len = (bslash) ? (size_t) (bslash - tmp + 1) : strlen (tmp); 547 548 /* Double all backslashes, since demand_copy_C_string (used by 549 s_stab to extract the part in quotes) will try to replace them as 550 escape sequences. backslash may appear in a filespec. */ 551 strncpy (bufp, tmp, len); 552 553 tmp += len; 554 bufp += len; 555 556 if (bslash != NULL) 557 *bufp++ = '\\'; 558 } 559 560 sprintf (bufp, "\",%d,0,0,%s\n", type, sym); 561 562 input_line_pointer = buf; 563 s_stab ('s'); 564 colon (sym); 565 566 if (last_file != NULL) 567 free (last_file); 568 last_file = xstrdup (file); 569 570 free (buf); 571 572 input_line_pointer = hold; 573 } 574 575 /* Generate stabs debugging information for the current line. This is 576 used to produce debugging information for an assembler file. */ 577 578 void 579 stabs_generate_asm_lineno (void) 580 { 581 static int label_count; 582 char *hold; 583 char *file; 584 unsigned int lineno; 585 char *buf; 586 char sym[30]; 587 /* Remember the last file/line and avoid duplicates. */ 588 static unsigned int prev_lineno = -1; 589 static char *prev_file = NULL; 590 591 /* Rather than try to do this in some efficient fashion, we just 592 generate a string and then parse it again. That lets us use the 593 existing stabs hook, which expect to see a string, rather than 594 inventing new ones. */ 595 596 hold = input_line_pointer; 597 598 as_where (&file, &lineno); 599 600 /* Don't emit sequences of stabs for the same line. */ 601 if (prev_file == NULL) 602 { 603 /* First time thru. */ 604 prev_file = xstrdup (file); 605 prev_lineno = lineno; 606 } 607 else if (lineno == prev_lineno 608 && strcmp (file, prev_file) == 0) 609 { 610 /* Same file/line as last time. */ 611 return; 612 } 613 else 614 { 615 /* Remember file/line for next time. */ 616 prev_lineno = lineno; 617 if (strcmp (file, prev_file) != 0) 618 { 619 free (prev_file); 620 prev_file = xstrdup (file); 621 } 622 } 623 624 /* Let the world know that we are in the middle of generating a 625 piece of stabs line debugging information. */ 626 outputting_stabs_line_debug = 1; 627 628 generate_asm_file (N_SOL, file); 629 630 sprintf (sym, "%sL%d", FAKE_LABEL_NAME, label_count); 631 ++label_count; 632 633 if (in_dot_func_p) 634 { 635 buf = (char *) alloca (100 + strlen (current_function_label)); 636 sprintf (buf, "%d,0,%d,%s-%s\n", N_SLINE, lineno, 637 sym, current_function_label); 638 } 639 else 640 { 641 buf = (char *) alloca (100); 642 sprintf (buf, "%d,0,%d,%s\n", N_SLINE, lineno, sym); 643 } 644 input_line_pointer = buf; 645 s_stab ('n'); 646 colon (sym); 647 648 input_line_pointer = hold; 649 outputting_stabs_line_debug = 0; 650 } 651 652 /* Emit a function stab. 653 All assembler functions are assumed to have return type `void'. */ 654 655 void 656 stabs_generate_asm_func (const char *funcname, const char *startlabname) 657 { 658 static int void_emitted_p; 659 char *hold = input_line_pointer; 660 char *buf; 661 char *file; 662 unsigned int lineno; 663 664 if (! void_emitted_p) 665 { 666 input_line_pointer = "\"void:t1=1\",128,0,0,0"; 667 s_stab ('s'); 668 void_emitted_p = 1; 669 } 670 671 as_where (&file, &lineno); 672 if (asprintf (&buf, "\"%s:F1\",%d,0,%d,%s", 673 funcname, N_FUN, lineno + 1, startlabname) == -1) 674 as_fatal ("%s", xstrerror (errno)); 675 input_line_pointer = buf; 676 s_stab ('s'); 677 free (buf); 678 679 input_line_pointer = hold; 680 current_function_label = xstrdup (startlabname); 681 in_dot_func_p = 1; 682 } 683 684 /* Emit a stab to record the end of a function. */ 685 686 void 687 stabs_generate_asm_endfunc (const char *funcname ATTRIBUTE_UNUSED, 688 const char *startlabname) 689 { 690 static int label_count; 691 char *hold = input_line_pointer; 692 char *buf; 693 char sym[30]; 694 695 sprintf (sym, "%sendfunc%d", FAKE_LABEL_NAME, label_count); 696 ++label_count; 697 colon (sym); 698 699 if (asprintf (&buf, "\"\",%d,0,0,%s-%s", N_FUN, sym, startlabname) == -1) 700 as_fatal ("%s", xstrerror (errno)); 701 input_line_pointer = buf; 702 s_stab ('s'); 703 free (buf); 704 705 input_line_pointer = hold; 706 in_dot_func_p = 0; 707 current_function_label = NULL; 708 } 709