1 /* Generic stabs parsing for gas. 2 Copyright (C) 1989-2014 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 #include "as.h" 22 #include "filenames.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 xfree ((char *) dir); 505 } 506 generate_asm_file (N_SO, file); 507 } 508 509 /* Generate stabs debugging information to denote the source file. 510 TYPE is one of N_SO, N_SOL. */ 511 512 static void 513 generate_asm_file (int type, char *file) 514 { 515 static char *last_file; 516 static int label_count; 517 char *hold; 518 char sym[30]; 519 char *buf; 520 char *tmp = file; 521 char *file_endp = file + strlen (file); 522 char *bufp; 523 524 if (last_file != NULL 525 && filename_cmp (last_file, file) == 0) 526 return; 527 528 /* Rather than try to do this in some efficient fashion, we just 529 generate a string and then parse it again. That lets us use the 530 existing stabs hook, which expect to see a string, rather than 531 inventing new ones. */ 532 hold = input_line_pointer; 533 534 sprintf (sym, "%sF%d", FAKE_LABEL_NAME, label_count); 535 ++label_count; 536 537 /* Allocate enough space for the file name (possibly extended with 538 doubled up backslashes), the symbol name, and the other characters 539 that make up a stabs file directive. */ 540 bufp = buf = (char *) xmalloc (2 * strlen (file) + strlen (sym) + 12); 541 542 *bufp++ = '"'; 543 544 while (tmp < file_endp) 545 { 546 char *bslash = strchr (tmp, '\\'); 547 size_t len = (bslash) ? (size_t) (bslash - tmp + 1) : strlen (tmp); 548 549 /* Double all backslashes, since demand_copy_C_string (used by 550 s_stab to extract the part in quotes) will try to replace them as 551 escape sequences. backslash may appear in a filespec. */ 552 strncpy (bufp, tmp, len); 553 554 tmp += len; 555 bufp += len; 556 557 if (bslash != NULL) 558 *bufp++ = '\\'; 559 } 560 561 sprintf (bufp, "\",%d,0,0,%s\n", type, sym); 562 563 input_line_pointer = buf; 564 s_stab ('s'); 565 colon (sym); 566 567 if (last_file != NULL) 568 free (last_file); 569 last_file = xstrdup (file); 570 571 free (buf); 572 573 input_line_pointer = hold; 574 } 575 576 /* Generate stabs debugging information for the current line. This is 577 used to produce debugging information for an assembler file. */ 578 579 void 580 stabs_generate_asm_lineno (void) 581 { 582 static int label_count; 583 char *hold; 584 char *file; 585 unsigned int lineno; 586 char *buf; 587 char sym[30]; 588 /* Remember the last file/line and avoid duplicates. */ 589 static unsigned int prev_lineno = -1; 590 static char *prev_file = NULL; 591 592 /* Rather than try to do this in some efficient fashion, we just 593 generate a string and then parse it again. That lets us use the 594 existing stabs hook, which expect to see a string, rather than 595 inventing new ones. */ 596 597 hold = input_line_pointer; 598 599 as_where (&file, &lineno); 600 601 /* Don't emit sequences of stabs for the same line. */ 602 if (prev_file == NULL) 603 { 604 /* First time thru. */ 605 prev_file = xstrdup (file); 606 prev_lineno = lineno; 607 } 608 else if (lineno == prev_lineno 609 && filename_cmp (file, prev_file) == 0) 610 { 611 /* Same file/line as last time. */ 612 return; 613 } 614 else 615 { 616 /* Remember file/line for next time. */ 617 prev_lineno = lineno; 618 if (filename_cmp (file, prev_file) != 0) 619 { 620 free (prev_file); 621 prev_file = xstrdup (file); 622 } 623 } 624 625 /* Let the world know that we are in the middle of generating a 626 piece of stabs line debugging information. */ 627 outputting_stabs_line_debug = 1; 628 629 generate_asm_file (N_SOL, file); 630 631 sprintf (sym, "%sL%d", FAKE_LABEL_NAME, label_count); 632 ++label_count; 633 634 if (in_dot_func_p) 635 { 636 buf = (char *) alloca (100 + strlen (current_function_label)); 637 sprintf (buf, "%d,0,%d,%s-%s\n", N_SLINE, lineno, 638 sym, current_function_label); 639 } 640 else 641 { 642 buf = (char *) alloca (100); 643 sprintf (buf, "%d,0,%d,%s\n", N_SLINE, lineno, sym); 644 } 645 input_line_pointer = buf; 646 s_stab ('n'); 647 colon (sym); 648 649 input_line_pointer = hold; 650 outputting_stabs_line_debug = 0; 651 } 652 653 /* Emit a function stab. 654 All assembler functions are assumed to have return type `void'. */ 655 656 void 657 stabs_generate_asm_func (const char *funcname, const char *startlabname) 658 { 659 static int void_emitted_p; 660 char *hold = input_line_pointer; 661 char *buf; 662 char *file; 663 unsigned int lineno; 664 665 if (! void_emitted_p) 666 { 667 input_line_pointer = "\"void:t1=1\",128,0,0,0"; 668 s_stab ('s'); 669 void_emitted_p = 1; 670 } 671 672 as_where (&file, &lineno); 673 if (asprintf (&buf, "\"%s:F1\",%d,0,%d,%s", 674 funcname, N_FUN, lineno + 1, startlabname) == -1) 675 as_fatal ("%s", xstrerror (errno)); 676 input_line_pointer = buf; 677 s_stab ('s'); 678 free (buf); 679 680 input_line_pointer = hold; 681 current_function_label = xstrdup (startlabname); 682 in_dot_func_p = 1; 683 } 684 685 /* Emit a stab to record the end of a function. */ 686 687 void 688 stabs_generate_asm_endfunc (const char *funcname ATTRIBUTE_UNUSED, 689 const char *startlabname) 690 { 691 static int label_count; 692 char *hold = input_line_pointer; 693 char *buf; 694 char sym[30]; 695 696 sprintf (sym, "%sendfunc%d", FAKE_LABEL_NAME, label_count); 697 ++label_count; 698 colon (sym); 699 700 if (asprintf (&buf, "\"\",%d,0,0,%s-%s", N_FUN, sym, startlabname) == -1) 701 as_fatal ("%s", xstrerror (errno)); 702 input_line_pointer = buf; 703 s_stab ('s'); 704 free (buf); 705 706 input_line_pointer = hold; 707 in_dot_func_p = 0; 708 current_function_label = NULL; 709 } 710
