stabs.c revision 89857
1/* Generic stabs parsing for gas. 2 Copyright 1989, 1990, 1991, 1993, 1995, 1996, 1997, 1998, 2000, 2001 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#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 35int outputting_stabs_line_debug = 0; 36 37static void s_stab_generic PARAMS ((int, char *, char *)); 38static void generate_asm_file PARAMS ((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. */ 53static int in_dot_func_p; 54 55/* Label at start of current function if in_dot_func_p != 0. */ 56static 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 82unsigned int 83get_stab_string_offset (string, stabstr_secname) 84 const char *string; 85 const char *stabstr_secname; 86{ 87 unsigned int length; 88 unsigned int retval; 89 segT save_seg; 90 subsegT save_subseg; 91 segT seg; 92 char *p; 93 94 if (! SEPARATE_STAB_SECTIONS) 95 abort (); 96 97 length = strlen (string); 98 99 save_seg = now_seg; 100 save_subseg = now_subseg; 101 102 /* Create the stab string section. */ 103 seg = subseg_new (stabstr_secname, 0); 104 105 retval = seg_info (seg)->stabu.stab_string_size; 106 if (retval <= 0) 107 { 108 /* Make sure the first string is empty. */ 109 p = frag_more (1); 110 *p = 0; 111 retval = seg_info (seg)->stabu.stab_string_size = 1; 112#ifdef BFD_ASSEMBLER 113 bfd_set_section_flags (stdoutput, seg, SEC_READONLY | SEC_DEBUGGING); 114 if (seg->name == stabstr_secname) 115 seg->name = xstrdup (stabstr_secname); 116#endif 117 } 118 119 if (length > 0) 120 { /* Ordinary case. */ 121 p = frag_more (length + 1); 122 strcpy (p, string); 123 124 seg_info (seg)->stabu.stab_string_size += length + 1; 125 } 126 else 127 retval = 0; 128 129 subseg_set (save_seg, save_subseg); 130 131 return retval; 132} 133 134#ifdef AOUT_STABS 135#ifndef OBJ_PROCESS_STAB 136#define OBJ_PROCESS_STAB(SEG,W,S,T,O,D) aout_process_stab(W,S,T,O,D) 137#endif 138 139/* Here instead of obj-aout.c because other formats use it too. */ 140void 141aout_process_stab (what, string, type, other, desc) 142 int what; 143 const char *string; 144 int type, other, desc; 145{ 146 /* Put the stab information in the symbol table. */ 147 symbolS *symbol; 148 149 /* Create the symbol now, but only insert it into the symbol chain 150 after any symbols mentioned in the value expression get into the 151 symbol chain. This is to avoid "continuation symbols" (where one 152 ends in "\" and the debug info is continued in the next .stabs 153 directive) from being separated by other random symbols. */ 154 symbol = symbol_create (string, undefined_section, 0, 155 (struct frag *) NULL); 156 if (what == 's' || what == 'n') 157 { 158 /* Pick up the value from the input line. */ 159 symbol_set_frag (symbol, &zero_address_frag); 160 pseudo_set (symbol); 161 } 162 else 163 { 164 /* .stabd sets the name to NULL. Why? */ 165 S_SET_NAME (symbol, NULL); 166 symbol_set_frag (symbol, frag_now); 167 S_SET_VALUE (symbol, (valueT) frag_now_fix ()); 168 } 169 170 symbol_append (symbol, symbol_lastP, &symbol_rootP, &symbol_lastP); 171 172 S_SET_TYPE (symbol, type); 173 S_SET_OTHER (symbol, other); 174 S_SET_DESC (symbol, desc); 175} 176#endif 177 178/* This can handle different kinds of stabs (s,n,d) and different 179 kinds of stab sections. */ 180 181static void 182s_stab_generic (what, stab_secname, stabstr_secname) 183 int what; 184 char *stab_secname; 185 char *stabstr_secname; 186{ 187 long longint; 188 char *string, *saved_string_obstack_end; 189 int type; 190 int other; 191 int desc; 192 193 /* The general format is: 194 .stabs "STRING",TYPE,OTHER,DESC,VALUE 195 .stabn TYPE,OTHER,DESC,VALUE 196 .stabd TYPE,OTHER,DESC 197 At this point input_line_pointer points after the pseudo-op and 198 any trailing whitespace. The argument what is one of 's', 'n' or 199 'd' indicating which type of .stab this is. */ 200 201 if (what != 's') 202 { 203 string = ""; 204 saved_string_obstack_end = 0; 205 } 206 else 207 { 208 int length; 209 210 string = demand_copy_C_string (&length); 211 /* FIXME: We should probably find some other temporary storage 212 for string, rather than leaking memory if someone else 213 happens to use the notes obstack. */ 214 saved_string_obstack_end = notes.next_free; 215 SKIP_WHITESPACE (); 216 if (*input_line_pointer == ',') 217 input_line_pointer++; 218 else 219 { 220 as_warn (_(".stab%c: missing comma"), what); 221 ignore_rest_of_line (); 222 return; 223 } 224 } 225 226 if (get_absolute_expression_and_terminator (&longint) != ',') 227 { 228 as_warn (_(".stab%c: missing comma"), what); 229 ignore_rest_of_line (); 230 return; 231 } 232 type = longint; 233 234 if (get_absolute_expression_and_terminator (&longint) != ',') 235 { 236 as_warn (_(".stab%c: missing comma"), what); 237 ignore_rest_of_line (); 238 return; 239 } 240 other = longint; 241 242 desc = get_absolute_expression (); 243 if (what == 's' || what == 'n') 244 { 245 if (*input_line_pointer != ',') 246 { 247 as_warn (_(".stab%c: missing comma"), what); 248 ignore_rest_of_line (); 249 return; 250 } 251 input_line_pointer++; 252 SKIP_WHITESPACE (); 253 } 254 255#ifdef TC_PPC 256#ifdef OBJ_ELF 257 /* Solaris on PowerPC has decided that .stabd can take 4 arguments, so if we were 258 given 4 arguments, make it a .stabn */ 259 else if (what == 'd') 260 { 261 char *save_location = input_line_pointer; 262 263 SKIP_WHITESPACE (); 264 if (*input_line_pointer == ',') 265 { 266 input_line_pointer++; 267 what = 'n'; 268 } 269 else 270 input_line_pointer = save_location; 271 } 272#endif /* OBJ_ELF */ 273#endif /* TC_PPC */ 274 275#ifndef NO_LISTING 276 if (listing) 277 { 278 switch (type) 279 { 280 case N_SLINE: 281 listing_source_line ((unsigned int) desc); 282 break; 283 case N_SO: 284 case N_SOL: 285 listing_source_file (string); 286 break; 287 } 288 } 289#endif /* ! NO_LISTING */ 290 291 /* We have now gathered the type, other, and desc information. For 292 .stabs or .stabn, input_line_pointer is now pointing at the 293 value. */ 294 295 if (SEPARATE_STAB_SECTIONS) 296 /* Output the stab information in a separate section. This is used 297 at least for COFF and ELF. */ 298 { 299 segT saved_seg = now_seg; 300 subsegT saved_subseg = now_subseg; 301 fragS *saved_frag = frag_now; 302 valueT dot; 303 segT seg; 304 unsigned int stroff; 305 char *p; 306 307 static segT cached_sec; 308 static char *cached_secname; 309 310 dot = frag_now_fix (); 311 312#ifdef md_flush_pending_output 313 md_flush_pending_output (); 314#endif 315 316 if (cached_secname && !strcmp (cached_secname, stab_secname)) 317 { 318 seg = cached_sec; 319 subseg_set (seg, 0); 320 } 321 else 322 { 323 seg = subseg_new (stab_secname, 0); 324 if (cached_secname) 325 free (cached_secname); 326 cached_secname = xstrdup (stab_secname); 327 cached_sec = seg; 328 } 329 330 if (! seg_info (seg)->hadone) 331 { 332#ifdef BFD_ASSEMBLER 333 bfd_set_section_flags (stdoutput, seg, 334 SEC_READONLY | SEC_RELOC | SEC_DEBUGGING); 335#endif 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 const char *fake; 367 symbolS *symbol; 368 expressionS exp; 369 370 /* Arrange for a value representing the current location. */ 371 fake = FAKE_LABEL_NAME; 372 symbol = symbol_new (fake, saved_seg, dot, saved_frag); 373 374 exp.X_op = O_symbol; 375 exp.X_add_symbol = symbol; 376 exp.X_add_number = 0; 377 378 emit_expr (&exp, 4); 379 } 380 381#ifdef OBJ_PROCESS_STAB 382 OBJ_PROCESS_STAB (seg, what, string, type, other, desc); 383#endif 384 385 subseg_set (saved_seg, saved_subseg); 386 } 387 else 388 { 389#ifdef OBJ_PROCESS_STAB 390 OBJ_PROCESS_STAB (0, what, string, type, other, desc); 391#else 392 abort (); 393#endif 394 } 395 396 demand_empty_rest_of_line (); 397} 398 399/* Regular stab directive. */ 400 401void 402s_stab (what) 403 int what; 404{ 405 s_stab_generic (what, STAB_SECTION_NAME, STAB_STRING_SECTION_NAME); 406} 407 408/* "Extended stabs", used in Solaris only now. */ 409 410void 411s_xstab (what) 412 int what; 413{ 414 int length; 415 char *stab_secname, *stabstr_secname; 416 static char *saved_secname, *saved_strsecname; 417 418 /* @@ MEMORY LEAK: This allocates a copy of the string, but in most 419 cases it will be the same string, so we could release the storage 420 back to the obstack it came from. */ 421 stab_secname = demand_copy_C_string (&length); 422 SKIP_WHITESPACE (); 423 if (*input_line_pointer == ',') 424 input_line_pointer++; 425 else 426 { 427 as_bad (_("comma missing in .xstabs")); 428 ignore_rest_of_line (); 429 return; 430 } 431 432 /* To get the name of the stab string section, simply add "str" to 433 the stab section name. */ 434 if (saved_secname == 0 || strcmp (saved_secname, stab_secname)) 435 { 436 stabstr_secname = (char *) xmalloc (strlen (stab_secname) + 4); 437 strcpy (stabstr_secname, stab_secname); 438 strcat (stabstr_secname, "str"); 439 if (saved_secname) 440 { 441 free (saved_secname); 442 free (saved_strsecname); 443 } 444 saved_secname = stab_secname; 445 saved_strsecname = stabstr_secname; 446 } 447 s_stab_generic (what, saved_secname, saved_strsecname); 448} 449 450#ifdef S_SET_DESC 451 452/* Frob invented at RMS' request. Set the n_desc of a symbol. */ 453 454void 455s_desc (ignore) 456 int ignore ATTRIBUTE_UNUSED; 457{ 458 char *name; 459 char c; 460 char *p; 461 symbolS *symbolP; 462 int temp; 463 464 name = input_line_pointer; 465 c = get_symbol_end (); 466 p = input_line_pointer; 467 *p = c; 468 SKIP_WHITESPACE (); 469 if (*input_line_pointer != ',') 470 { 471 *p = 0; 472 as_bad (_("expected comma after \"%s\""), name); 473 *p = c; 474 ignore_rest_of_line (); 475 } 476 else 477 { 478 input_line_pointer++; 479 temp = get_absolute_expression (); 480 *p = 0; 481 symbolP = symbol_find_or_make (name); 482 *p = c; 483 S_SET_DESC (symbolP, temp); 484 } 485 demand_empty_rest_of_line (); 486} /* s_desc() */ 487 488#endif /* defined (S_SET_DESC) */ 489 490/* Generate stabs debugging information to denote the main source file. */ 491 492void 493stabs_generate_asm_file () 494{ 495 char *file; 496 unsigned int lineno; 497 498 as_where (&file, &lineno); 499 generate_asm_file (N_SO, file); 500} 501 502/* Generate stabs debugging information to denote the source file. 503 TYPE is one of N_SO, N_SOL. */ 504 505static void 506generate_asm_file (type, file) 507 int type; 508 char *file; 509{ 510 static char *last_file; 511 static int label_count; 512 char *hold; 513 char sym[30]; 514 char *buf; 515 char *tmp = file; 516 char *endp = file + strlen (file); 517 char *bufp = buf; 518 519 if (last_file != NULL 520 && strcmp (last_file, file) == 0) 521 return; 522 523 /* Rather than try to do this in some efficient fashion, we just 524 generate a string and then parse it again. That lets us use the 525 existing stabs hook, which expect to see a string, rather than 526 inventing new ones. */ 527 hold = input_line_pointer; 528 529 sprintf (sym, "%sF%d", FAKE_LABEL_NAME, label_count); 530 ++label_count; 531 532 /* Allocate enough space for the file name (possibly extended with 533 doubled up backslashes), the symbol name, and the other characters 534 that make up a stabs file directive. */ 535 bufp = buf = xmalloc (2 * strlen (file) + strlen (sym) + 12); 536 537 *bufp++ = '"'; 538 539 while (tmp < endp) 540 { 541 char *bslash = strchr (tmp, '\\'); 542 size_t len = (bslash) ? (size_t) (bslash - tmp + 1) : strlen (tmp); 543 544 /* Double all backslashes, since demand_copy_C_string (used by 545 s_stab to extract the part in quotes) will try to replace them as 546 escape sequences. backslash may appear in a filespec. */ 547 strncpy (bufp, tmp, len); 548 549 tmp += len; 550 bufp += len; 551 552 if (bslash != NULL) 553 *bufp++ = '\\'; 554 } 555 556 sprintf (bufp, "\",%d,0,0,%s\n", type, sym); 557 558 input_line_pointer = buf; 559 s_stab ('s'); 560 colon (sym); 561 562 if (last_file != NULL) 563 free (last_file); 564 last_file = xstrdup (file); 565 566 free (buf); 567 568 input_line_pointer = hold; 569} 570 571/* Generate stabs debugging information for the current line. This is 572 used to produce debugging information for an assembler file. */ 573 574void 575stabs_generate_asm_lineno () 576{ 577 static int label_count; 578 char *hold; 579 char *file; 580 unsigned int lineno; 581 char *buf; 582 char sym[30]; 583 /* Remember the last file/line and avoid duplicates. */ 584 static unsigned int prev_lineno = -1; 585 static char *prev_file = NULL; 586 587 /* Rather than try to do this in some efficient fashion, we just 588 generate a string and then parse it again. That lets us use the 589 existing stabs hook, which expect to see a string, rather than 590 inventing new ones. */ 591 592 hold = input_line_pointer; 593 594 as_where (&file, &lineno); 595 596 /* Don't emit sequences of stabs for the same line. */ 597 if (prev_file == NULL) 598 { 599 /* First time thru. */ 600 prev_file = xstrdup (file); 601 prev_lineno = lineno; 602 } 603 else if (lineno == prev_lineno 604 && strcmp (file, prev_file) == 0) 605 { 606 /* Same file/line as last time. */ 607 return; 608 } 609 else 610 { 611 /* Remember file/line for next time. */ 612 prev_lineno = lineno; 613 if (strcmp (file, prev_file) != 0) 614 { 615 free (prev_file); 616 prev_file = xstrdup (file); 617 } 618 } 619 620 /* Let the world know that we are in the middle of generating a 621 piece of stabs line debugging information. */ 622 outputting_stabs_line_debug = 1; 623 624 generate_asm_file (N_SOL, file); 625 626 sprintf (sym, "%sL%d", FAKE_LABEL_NAME, label_count); 627 ++label_count; 628 629 if (in_dot_func_p) 630 { 631 buf = (char *) alloca (100 + strlen (current_function_label)); 632 sprintf (buf, "%d,0,%d,%s-%s\n", N_SLINE, lineno, 633 sym, current_function_label); 634 } 635 else 636 { 637 buf = (char *) alloca (100); 638 sprintf (buf, "%d,0,%d,%s\n", N_SLINE, lineno, sym); 639 } 640 input_line_pointer = buf; 641 s_stab ('n'); 642 colon (sym); 643 644 input_line_pointer = hold; 645 outputting_stabs_line_debug = 0; 646} 647 648/* Emit a function stab. 649 All assembler functions are assumed to have return type `void'. */ 650 651void 652stabs_generate_asm_func (funcname, startlabname) 653 const char *funcname; 654 const char *startlabname; 655{ 656 static int void_emitted_p; 657 char *hold = input_line_pointer; 658 char *buf; 659 char *file; 660 unsigned int lineno; 661 662 if (! void_emitted_p) 663 { 664 input_line_pointer = "\"void:t1=1\",128,0,0,0"; 665 s_stab ('s'); 666 void_emitted_p = 1; 667 } 668 669 as_where (&file, &lineno); 670 asprintf (&buf, "\"%s:F1\",%d,0,%d,%s", 671 funcname, N_FUN, lineno + 1, startlabname); 672 input_line_pointer = buf; 673 s_stab ('s'); 674 free (buf); 675 676 input_line_pointer = hold; 677 current_function_label = xstrdup (startlabname); 678 in_dot_func_p = 1; 679} 680 681/* Emit a stab to record the end of a function. */ 682 683void 684stabs_generate_asm_endfunc (funcname, startlabname) 685 const char *funcname ATTRIBUTE_UNUSED; 686 const char *startlabname; 687{ 688 static int label_count; 689 char *hold = input_line_pointer; 690 char *buf; 691 char sym[30]; 692 693 sprintf (sym, "%sendfunc%d", FAKE_LABEL_NAME, label_count); 694 ++label_count; 695 colon (sym); 696 697 asprintf (&buf, "\"\",%d,0,0,%s-%s", N_FUN, sym, startlabname); 698 input_line_pointer = buf; 699 s_stab ('s'); 700 free (buf); 701 702 input_line_pointer = hold; 703 in_dot_func_p = 0; 704 current_function_label = NULL; 705} 706