src/symtab.c

   1 /* Symbol table manager for Bison.
   2
   3    Copyright (C) 1984, 1989, 2000, 2001, 2002, 2004, 2005, 2006 Free
   4    Software Foundation, Inc.
   5
   6    This file is part of Bison, the GNU Compiler Compiler.
   7
   8    Bison is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    Bison is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with Bison; see the file COPYING.  If not, write to
  20    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include <config.h>
  24 #include "system.h"
  25
  26 #include <hash.h>
  27 #include <quotearg.h>
  28
  29 #include "complain.h"
  30 #include "gram.h"
  31 #include "symtab.h"
  32
  33 /*------------------------.
  34 | Distinguished symbols.  |
  35 `------------------------*/
  36
  37 symbol *errtoken = NULL;
  38 symbol *undeftoken = NULL;
  39 symbol *endtoken = NULL;
  40 symbol *accept = NULL;
  41 symbol *startsymbol = NULL;
  42 location startsymbol_location;
  43
  44 /*-----------------------------------.
  45 | Default %destructor and %printer.  |
  46 `-----------------------------------*/
  47
  48 static const char *default_destructor = NULL;
  49 static location default_destructor_location;
  50 static const char *default_printer = NULL;
  51 static location default_printer_location;
  52
  53 /*---------------------------------.
  54 | Create a new symbol, named TAG.  |
  55 `---------------------------------*/
  56
  57 static symbol *
  58 symbol_new (uniqstr tag, location loc)
  59 {
  60   symbol *res = xmalloc (sizeof *res);
  61
  62   uniqstr_assert (tag);
  63   res->tag = tag;
  64   res->location = loc;
  65
  66   res->type_name = NULL;
  67   res->destructor = NULL;
  68   res->printer = NULL;
  69
  70   res->number = NUMBER_UNDEFINED;
  71   res->prec = 0;
  72   res->assoc = undef_assoc;
  73   res->user_token_number = USER_NUMBER_UNDEFINED;
  74
  75   res->alias = NULL;
  76   res->class = unknown_sym;
  77   res->declared = false;
  78
  79   if (nsyms == SYMBOL_NUMBER_MAXIMUM)
  80     fatal (_("too many symbols in input grammar (limit is %d)"),
  81            SYMBOL_NUMBER_MAXIMUM);
  82   nsyms++;
  83   return res;
  84 }
  85
  86 /*----------------------------------------.
  87 | Create a new semantic type, named TAG.  |
  88 `----------------------------------------*/
  89
  90 static semantic_type *
  91 semantic_type_new (uniqstr tag)
  92 {
  93   semantic_type *res = xmalloc (sizeof *res);
  94
  95   uniqstr_assert (tag);
  96   res->tag = tag;
  97   res->destructor = NULL;
  98   res->printer = NULL;
  99
 100   return res;
 101 }
 102
 103
 104 /*-----------------.
 105 | Print a symbol.  |
 106 `-----------------*/
 107
 108 #define SYMBOL_ATTR_PRINT(Attr)                         \
 109   if (s->Attr)                                          \
 110     fprintf (f, " %s { %s }", #Attr, s->Attr)
 111
 112 void
 113 symbol_print (symbol *s, FILE *f)
 114 {
 115   if (s)
 116     {
 117       fprintf (f, "\"%s\"", s->tag);
 118       SYMBOL_ATTR_PRINT (type_name);
 119       SYMBOL_ATTR_PRINT (destructor);
 120       SYMBOL_ATTR_PRINT (printer);
 121     }
 122   else
 123     fprintf (f, "<NULL>");
 124 }
 125
 126 #undef SYMBOL_ATTR_PRINT
 127
 128 /*------------------------------------------------------------------.
 129 | Complain that S's WHAT is redeclared at SECOND, and was first set |
 130 | at FIRST.                                                         |
 131 `------------------------------------------------------------------*/
 132
 133 static void
 134 symbol_redeclaration (symbol *s, const char *what, location first,
 135                       location second)
 136 {
 137   complain_at (second, _("%s redeclaration for %s"), what, s->tag);
 138   complain_at (first, _("previous declaration"));
 139 }
 140
 141 static void
 142 semantic_type_redeclaration (semantic_type *s, const char *what, location first,
 143                              location second)
 144 {
 145   complain_at (second, _("%s redeclaration for <%s>"), what, s->tag);
 146   complain_at (first, _("previous declaration"));
 147 }
 148
 149
 150 /*-----------------------------------------------------------------.
 151 | Set the TYPE_NAME associated with SYM.  Does nothing if passed 0 |
 152 | as TYPE_NAME.                                                    |
 153 `-----------------------------------------------------------------*/
 154
 155 void
 156 symbol_type_set (symbol *sym, uniqstr type_name, location loc)
 157 {
 158   if (type_name)
 159     {
 160       if (sym->type_name)
 161         symbol_redeclaration (sym, "%type", sym->type_location, loc);
 162       uniqstr_assert (type_name);
 163       sym->type_name = type_name;
 164       sym->type_location = loc;
 165     }
 166 }
 167
 168
 169 /*------------------------------------------------------------------.
 170 | Set the DESTRUCTOR associated with SYM.  Do nothing if passed 0.  |
 171 `------------------------------------------------------------------*/
 172
 173 void
 174 symbol_destructor_set (symbol *sym, const char *destructor, location loc)
 175 {
 176   if (destructor)
 177     {
 178       if (sym->destructor)
 179         symbol_redeclaration (sym, "%destructor", sym->destructor_location,
 180                               loc);
 181       sym->destructor = destructor;
 182       sym->destructor_location = loc;
 183     }
 184 }
 185
 186 /*-------------------------------------------------------------------.
 187 | Set the DESTRUCTOR associated with TYPE.  Do nothing if passed 0.  |
 188 `-------------------------------------------------------------------*/
 189
 190 void
 191 semantic_type_destructor_set (semantic_type *type, const char *destructor,
 192                               location loc)
 193 {
 194   if (destructor)
 195     {
 196       if (type->destructor)
 197         semantic_type_redeclaration (type, "%destructor",
 198                                      type->destructor_location, loc);
 199       type->destructor = destructor;
 200       type->destructor_location = loc;
 201     }
 202 }
 203
 204 /*---------------------------------------.
 205 | Get the computed %destructor for SYM.  |
 206 `---------------------------------------*/
 207
 208 const char *
 209 symbol_destructor_get (symbol *sym)
 210 {
 211   /* Per-symbol %destructor.  */
 212   if (sym->destructor != NULL)
 213     return sym->destructor;
 214
 215   /* Per-type %destructor.  */
 216   if (sym->type_name)
 217     {
 218       semantic_type *type = semantic_type_get (sym->type_name);
 219       if (type->destructor)
 220         return type->destructor;
 221     }
 222
 223   /* Apply the default %destructor only to user-defined symbols.  */
 224   if (sym->tag[0] == '$' || sym == errtoken)
 225     return NULL;
 226   return default_destructor;
 227 }
 228
 229 /*---------------------------------------------------------------.
 230 | Get the grammar location of the %destructor computed for SYM.  |
 231 `---------------------------------------------------------------*/
 232
 233 location
 234 symbol_destructor_location_get (symbol *sym)
 235 {
 236   if (sym->destructor != NULL)
 237     return sym->destructor_location;
 238   if (sym->type_name)
 239     {
 240       semantic_type *type = semantic_type_get (sym->type_name);
 241       if (type->destructor)
 242         return type->destructor_location;
 243     }
 244   return default_destructor_location;
 245 }
 246
 247 /*---------------------------------------------------------------.
 248 | Set the PRINTER associated with SYM.  Do nothing if passed 0.  |
 249 `---------------------------------------------------------------*/
 250
 251 void
 252 symbol_printer_set (symbol *sym, const char *printer, location loc)
 253 {
 254   if (printer)
 255     {
 256       if (sym->printer)
 257         symbol_redeclaration (sym, "%printer", sym->printer_location, loc);
 258       sym->printer = printer;
 259       sym->printer_location = loc;
 260     }
 261 }
 262
 263 /*----------------------------------------------------------------.
 264 | Set the PRINTER associated with TYPE.  Do nothing if passed 0.  |
 265 `----------------------------------------------------------------*/
 266
 267 void
 268 semantic_type_printer_set (semantic_type *type, const char *printer,
 269                            location loc)
 270 {
 271   if (printer)
 272     {
 273       if (type->printer)
 274         semantic_type_redeclaration (type, "%printer", type->printer_location,
 275                                      loc);
 276       type->printer = printer;
 277       type->printer_location = loc;
 278     }
 279 }
 280
 281 /*------------------------------------.
 282 | Get the computed %printer for SYM.  |
 283 `------------------------------------*/
 284
 285 const char *
 286 symbol_printer_get (symbol *sym)
 287 {
 288   /* Per-symbol %printer.  */
 289   if (sym->printer != NULL)
 290     return sym->printer;
 291
 292   /* Per-type %printer.  */
 293   if (sym->type_name)
 294     {
 295       semantic_type *type = semantic_type_get (sym->type_name);
 296       if (type->printer)
 297         return type->printer;
 298     }
 299
 300   /* Apply the default %printer only to user-defined symbols.  */
 301   if (sym->tag[0] == '$' || sym == errtoken)
 302     return NULL;
 303   return default_printer;
 304 }
 305
 306 /*------------------------------------------------------------.
 307 | Get the grammar location of the %printer computed for SYM.  |
 308 `------------------------------------------------------------*/
 309
 310 location
 311 symbol_printer_location_get (symbol *sym)
 312 {
 313   if (sym->printer != NULL)
 314     return sym->printer_location;
 315   if (sym->type_name)
 316     {
 317       semantic_type *type = semantic_type_get (sym->type_name);
 318       if (type->printer)
 319         return type->printer_location;
 320     }
 321   return default_printer_location;
 322 }
 323
 324
 325 /*-----------------------------------------------------------------.
 326 | Set the PRECEDENCE associated with SYM.  Does nothing if invoked |
 327 | with UNDEF_ASSOC as ASSOC.                                       |
 328 `-----------------------------------------------------------------*/
 329
 330 void
 331 symbol_precedence_set (symbol *sym, int prec, assoc a, location loc)
 332 {
 333   if (a != undef_assoc)
 334     {
 335       if (sym->prec != 0)
 336         symbol_redeclaration (sym, assoc_to_string (a), sym->prec_location,
 337                               loc);
 338       sym->prec = prec;
 339       sym->assoc = a;
 340       sym->prec_location = loc;
 341     }
 342
 343   /* Only terminals have a precedence. */
 344   symbol_class_set (sym, token_sym, loc, false);
 345 }
 346
 347
 348 /*------------------------------------.
 349 | Set the CLASS associated with SYM.  |
 350 `------------------------------------*/
 351
 352 void
 353 symbol_class_set (symbol *sym, symbol_class class, location loc, bool declaring)
 354 {
 355   if (sym->class != unknown_sym && sym->class != class)
 356     {
 357       complain_at (loc, _("symbol %s redefined"), sym->tag);
 358       sym->declared = false;
 359     }
 360
 361   if (class == nterm_sym && sym->class != nterm_sym)
 362     sym->number = nvars++;
 363   else if (class == token_sym && sym->number == NUMBER_UNDEFINED)
 364     sym->number = ntokens++;
 365
 366   sym->class = class;
 367
 368   if (declaring)
 369     {
 370       if (sym->declared)
 371         warn_at (loc, _("symbol %s redeclared"), sym->tag);
 372       sym->declared = true;
 373     }
 374 }
 375
 376
 377 /*------------------------------------------------.
 378 | Set the USER_TOKEN_NUMBER associated with SYM.  |
 379 `------------------------------------------------*/
 380
 381 void
 382 symbol_user_token_number_set (symbol *sym, int user_token_number, location loc)
 383 {
 384   int *user_token_numberp;
 385
 386   aver (sym->class == token_sym);
 387
 388   if (sym->user_token_number != USER_NUMBER_ALIAS)
 389     user_token_numberp = &sym->user_token_number;
 390   else
 391     user_token_numberp = &sym->alias->user_token_number;
 392   if (*user_token_numberp != USER_NUMBER_UNDEFINED
 393       && *user_token_numberp != user_token_number)
 394     complain_at (loc, _("redefining user token number of %s"), sym->tag);
 395
 396   *user_token_numberp = user_token_number;
 397   /* User defined $end token? */
 398   if (user_token_number == 0)
 399     {
 400       endtoken = sym;
 401       endtoken->number = 0;
 402       /* It is always mapped to 0, so it was already counted in
 403          NTOKENS.  */
 404       --ntokens;
 405     }
 406 }
 407
 408
 409 /*----------------------------------------------------------.
 410 | If SYM is not defined, report an error, and consider it a |
 411 | nonterminal.                                              |
 412 `----------------------------------------------------------*/
 413
 414 static inline bool
 415 symbol_check_defined (symbol *sym)
 416 {
 417   if (sym->class == unknown_sym)
 418     {
 419       complain_at
 420         (sym->location,
 421          _("symbol %s is used, but is not defined as a token and has no rules"),
 422          sym->tag);
 423       sym->class = nterm_sym;
 424       sym->number = nvars++;
 425     }
 426
 427   return true;
 428 }
 429
 430 static bool
 431 symbol_check_defined_processor (void *sym, void *null ATTRIBUTE_UNUSED)
 432 {
 433   return symbol_check_defined (sym);
 434 }
 435
 436
 437 /*------------------------------------------------------------------.
 438 | Declare the new symbol SYM.  Make it an alias of SYMVAL, and type |
 439 | SYMVAL with SYM's type.                                           |
 440 `------------------------------------------------------------------*/
 441
 442 void
 443 symbol_make_alias (symbol *sym, symbol *symval, location loc)
 444 {
 445   if (symval->alias)
 446     warn_at (loc, _("symbol `%s' used more than once as a literal string"),
 447              symval->tag);
 448   else if (sym->alias)
 449     warn_at (loc, _("symbol `%s' given more than one literal string"),
 450              sym->tag);
 451   else
 452     {
 453       symval->class = token_sym;
 454       symval->user_token_number = sym->user_token_number;
 455       sym->user_token_number = USER_NUMBER_ALIAS;
 456       symval->alias = sym;
 457       sym->alias = symval;
 458       symval->number = sym->number;
 459       symbol_type_set (symval, sym->type_name, loc);
 460     }
 461 }
 462
 463
 464 /*---------------------------------------------------------.
 465 | Check that THIS, and its alias, have same precedence and |
 466 | associativity.                                           |
 467 `---------------------------------------------------------*/
 468
 469 static inline void
 470 symbol_check_alias_consistency (symbol *this)
 471 {
 472   symbol *alias = this;
 473   symbol *orig  = this->alias;
 474
 475   /* Check only those that _are_ the aliases.  */
 476   if (!(this->alias && this->user_token_number == USER_NUMBER_ALIAS))
 477     return;
 478
 479   if (orig->type_name != alias->type_name)
 480     {
 481       if (orig->type_name)
 482         symbol_type_set (alias, orig->type_name, orig->type_location);
 483       else
 484         symbol_type_set (orig, alias->type_name, alias->type_location);
 485     }
 486
 487
 488   if (orig->destructor || alias->destructor)
 489     {
 490       if (orig->destructor)
 491         symbol_destructor_set (alias, orig->destructor,
 492                                orig->destructor_location);
 493       else
 494         symbol_destructor_set (orig, alias->destructor,
 495                                alias->destructor_location);
 496     }
 497
 498   if (orig->printer || alias->printer)
 499     {
 500       if (orig->printer)
 501         symbol_printer_set (alias, orig->printer, orig->printer_location);
 502       else
 503         symbol_printer_set (orig, alias->printer, alias->printer_location);
 504     }
 505
 506   if (alias->prec || orig->prec)
 507     {
 508       if (orig->prec)
 509         symbol_precedence_set (alias, orig->prec, orig->assoc,
 510                                orig->prec_location);
 511       else
 512         symbol_precedence_set (orig, alias->prec, alias->assoc,
 513                                alias->prec_location);
 514     }
 515 }
 516
 517 static bool
 518 symbol_check_alias_consistency_processor (void *this,
 519                                           void *null ATTRIBUTE_UNUSED)
 520 {
 521   symbol_check_alias_consistency (this);
 522   return true;
 523 }
 524
 525
 526 /*-------------------------------------------------------------------.
 527 | Assign a symbol number, and write the definition of the token name |
 528 | into FDEFINES.  Put in SYMBOLS.                                    |
 529 `-------------------------------------------------------------------*/
 530
 531 static inline bool
 532 symbol_pack (symbol *this)
 533 {
 534   if (this->class == nterm_sym)
 535     {
 536       this->number += ntokens;
 537     }
 538   else if (this->alias)
 539     {
 540       /* This symbol and its alias are a single token defn.
 541          Allocate a tokno, and assign to both check agreement of
 542          prec and assoc fields and make both the same */
 543       if (this->number == NUMBER_UNDEFINED)
 544         {
 545           if (this == endtoken || this->alias == endtoken)
 546             this->number = this->alias->number = 0;
 547           else
 548             {
 549               aver (this->alias->number != NUMBER_UNDEFINED);
 550               this->number = this->alias->number;
 551             }
 552         }
 553       /* Do not do processing below for USER_NUMBER_ALIASes.  */
 554       if (this->user_token_number == USER_NUMBER_ALIAS)
 555         return true;
 556     }
 557   else /* this->class == token_sym */
 558     aver (this->number != NUMBER_UNDEFINED);
 559
 560   symbols[this->number] = this;
 561   return true;
 562 }
 563
 564 static bool
 565 symbol_pack_processor (void *this, void *null ATTRIBUTE_UNUSED)
 566 {
 567   return symbol_pack (this);
 568 }
 569
 570
 571
 572
 573 /*--------------------------------------------------.
 574 | Put THIS in TOKEN_TRANSLATIONS if it is a token.  |
 575 `--------------------------------------------------*/
 576
 577 static inline bool
 578 symbol_translation (symbol *this)
 579 {
 580   /* Non-terminal? */
 581   if (this->class == token_sym
 582       && this->user_token_number != USER_NUMBER_ALIAS)
 583     {
 584       /* A token which translation has already been set? */
 585       if (token_translations[this->user_token_number] != undeftoken->number)
 586         complain_at (this->location,
 587                      _("tokens %s and %s both assigned number %d"),
 588                      symbols[token_translations[this->user_token_number]]->tag,
 589                      this->tag, this->user_token_number);
 590
 591       token_translations[this->user_token_number] = this->number;
 592     }
 593
 594   return true;
 595 }
 596
 597 static bool
 598 symbol_translation_processor (void *this, void *null ATTRIBUTE_UNUSED)
 599 {
 600   return symbol_translation (this);
 601 }
 602
 603
 604 /*---------------------------------------.
 605 | Symbol and semantic type hash tables.  |
 606 `---------------------------------------*/
 607
 608 /* Initial capacity of symbol and semantic type hash table.  */
 609 #define HT_INITIAL_CAPACITY 257
 610
 611 static struct hash_table *symbol_table = NULL;
 612 static struct hash_table *semantic_type_table = NULL;
 613
 614 static inline bool
 615 hash_compare_symbol (const symbol *m1, const symbol *m2)
 616 {
 617   /* Since tags are unique, we can compare the pointers themselves.  */
 618   return UNIQSTR_EQ (m1->tag, m2->tag);
 619 }
 620
 621 static inline bool
 622 hash_compare_semantic_type (const semantic_type *m1, const semantic_type *m2)
 623 {
 624   /* Since names are unique, we can compare the pointers themselves.  */
 625   return UNIQSTR_EQ (m1->tag, m2->tag);
 626 }
 627
 628 static bool
 629 hash_symbol_comparator (void const *m1, void const *m2)
 630 {
 631   return hash_compare_symbol (m1, m2);
 632 }
 633
 634 static bool
 635 hash_semantic_type_comparator (void const *m1, void const *m2)
 636 {
 637   return hash_compare_semantic_type (m1, m2);
 638 }
 639
 640 static inline size_t
 641 hash_symbol (const symbol *m, size_t tablesize)
 642 {
 643   /* Since tags are unique, we can hash the pointer itself.  */
 644   return ((uintptr_t) m->tag) % tablesize;
 645 }
 646
 647 static inline size_t
 648 hash_semantic_type (const semantic_type *m, size_t tablesize)
 649 {
 650   /* Since names are unique, we can hash the pointer itself.  */
 651   return ((uintptr_t) m->tag) % tablesize;
 652 }
 653
 654 static size_t
 655 hash_symbol_hasher (void const *m, size_t tablesize)
 656 {
 657   return hash_symbol (m, tablesize);
 658 }
 659
 660 static size_t
 661 hash_semantic_type_hasher (void const *m, size_t tablesize)
 662 {
 663   return hash_semantic_type (m, tablesize);
 664 }
 665
 666 /*-------------------------------.
 667 | Create the symbol hash table.  |
 668 `-------------------------------*/
 669
 670 void
 671 symbols_new (void)
 672 {
 673   symbol_table = hash_initialize (HT_INITIAL_CAPACITY,
 674                                   NULL,
 675                                   hash_symbol_hasher,
 676                                   hash_symbol_comparator,
 677                                   free);
 678   semantic_type_table = hash_initialize (HT_INITIAL_CAPACITY,
 679                                          NULL,
 680                                          hash_semantic_type_hasher,
 681                                          hash_semantic_type_comparator,
 682                                          free);
 683 }
 684
 685
 686 /*----------------------------------------------------------------.
 687 | Find the symbol named KEY, and return it.  If it does not exist |
 688 | yet, create it.                                                 |
 689 `----------------------------------------------------------------*/
 690
 691 symbol *
 692 symbol_from_uniqstr (const uniqstr key, location loc)
 693 {
 694   symbol probe;
 695   symbol *entry;
 696
 697   probe.tag = key;
 698   entry = hash_lookup (symbol_table, &probe);
 699
 700   if (!entry)
 701     {
 702       /* First insertion in the hash. */
 703       entry = symbol_new (key, loc);
 704       hash_insert (symbol_table, entry);
 705     }
 706   return entry;
 707 }
 708
 709
 710 /*-----------------------------------------------------------------------.
 711 | Find the semantic type named KEY, and return it.  If it does not exist |
 712 | yet, create it.                                                        |
 713 `-----------------------------------------------------------------------*/
 714
 715 semantic_type *
 716 semantic_type_from_uniqstr (const uniqstr key)
 717 {
 718   semantic_type probe;
 719   semantic_type *entry;
 720
 721   probe.tag = key;
 722   entry = hash_lookup (semantic_type_table, &probe);
 723
 724   if (!entry)
 725     {
 726       /* First insertion in the hash. */
 727       entry = semantic_type_new (key);
 728       hash_insert (semantic_type_table, entry);
 729     }
 730   return entry;
 731 }
 732
 733
 734 /*----------------------------------------------------------------.
 735 | Find the symbol named KEY, and return it.  If it does not exist |
 736 | yet, create it.                                                 |
 737 `----------------------------------------------------------------*/
 738
 739 symbol *
 740 symbol_get (const char *key, location loc)
 741 {
 742   return symbol_from_uniqstr (uniqstr_new (key), loc);
 743 }
 744
 745
 746 /*-----------------------------------------------------------------------.
 747 | Find the semantic type named KEY, and return it.  If it does not exist |
 748 | yet, create it.                                                        |
 749 `-----------------------------------------------------------------------*/
 750
 751 semantic_type *
 752 semantic_type_get (const char *key)
 753 {
 754   return semantic_type_from_uniqstr (uniqstr_new (key));
 755 }
 756
 757
 758 /*------------------------------------------------------------------.
 759 | Generate a dummy nonterminal, whose name cannot conflict with the |
 760 | user's names.                                                     |
 761 `------------------------------------------------------------------*/
 762
 763 symbol *
 764 dummy_symbol_get (location loc)
 765 {
 766   /* Incremented for each generated symbol.  */
 767   static int dummy_count = 0;
 768   static char buf[256];
 769
 770   symbol *sym;
 771
 772   sprintf (buf, "@%d", ++dummy_count);
 773   sym = symbol_get (buf, loc);
 774   sym->class = nterm_sym;
 775   sym->number = nvars++;
 776   return sym;
 777 }
 778
 779 bool
 780 symbol_is_dummy (const symbol *sym)
 781 {
 782   return sym->tag[0] == '@';
 783 }
 784
 785 /*-------------------.
 786 | Free the symbols.  |
 787 `-------------------*/
 788
 789 void
 790 symbols_free (void)
 791 {
 792   hash_free (symbol_table);
 793   hash_free (semantic_type_table);
 794   free (symbols);
 795 }
 796
 797
 798 /*---------------------------------------------------------------.
 799 | Look for undefined symbols, report an error, and consider them |
 800 | terminals.                                                     |
 801 `---------------------------------------------------------------*/
 802
 803 static void
 804 symbols_do (Hash_processor processor, void *processor_data)
 805 {
 806   hash_do_for_each (symbol_table, processor, processor_data);
 807 }
 808
 809
 810 /*--------------------------------------------------------------.
 811 | Check that all the symbols are defined.  Report any undefined |
 812 | symbols and consider them nonterminals.                       |
 813 `--------------------------------------------------------------*/
 814
 815 void
 816 symbols_check_defined (void)
 817 {
 818   symbols_do (symbol_check_defined_processor, NULL);
 819 }
 820
 821 /*------------------------------------------------------------------.
 822 | Set TOKEN_TRANSLATIONS.  Check that no two symbols share the same |
 823 | number.                                                           |
 824 `------------------------------------------------------------------*/
 825
 826 static void
 827 symbols_token_translations_init (void)
 828 {
 829   bool num_256_available_p = true;
 830   int i;
 831
 832   /* Find the highest user token number, and whether 256, the POSIX
 833      preferred user token number for the error token, is used.  */
 834   max_user_token_number = 0;
 835   for (i = 0; i < ntokens; ++i)
 836     {
 837       symbol *this = symbols[i];
 838       if (this->user_token_number != USER_NUMBER_UNDEFINED)
 839         {
 840           if (this->user_token_number > max_user_token_number)
 841             max_user_token_number = this->user_token_number;
 842           if (this->user_token_number == 256)
 843             num_256_available_p = false;
 844         }
 845     }
 846
 847   /* If 256 is not used, assign it to error, to follow POSIX.  */
 848   if (num_256_available_p
 849       && errtoken->user_token_number == USER_NUMBER_UNDEFINED)
 850     errtoken->user_token_number = 256;
 851
 852   /* Set the missing user numbers. */
 853   if (max_user_token_number < 256)
 854     max_user_token_number = 256;
 855
 856   for (i = 0; i < ntokens; ++i)
 857     {
 858       symbol *this = symbols[i];
 859       if (this->user_token_number == USER_NUMBER_UNDEFINED)
 860         this->user_token_number = ++max_user_token_number;
 861       if (this->user_token_number > max_user_token_number)
 862         max_user_token_number = this->user_token_number;
 863     }
 864
 865   token_translations = xnmalloc (max_user_token_number + 1,
 866                                  sizeof *token_translations);
 867
 868   /* Initialize all entries for literal tokens to 2, the internal
 869      token number for $undefined, which represents all invalid inputs.
 870      */
 871   for (i = 0; i < max_user_token_number + 1; i++)
 872     token_translations[i] = undeftoken->number;
 873   symbols_do (symbol_translation_processor, NULL);
 874 }
 875
 876
 877 /*----------------------------------------------------------------.
 878 | Assign symbol numbers, and write definition of token names into |
 879 | FDEFINES.  Set up vectors SYMBOL_TABLE, TAGS of symbols.        |
 880 `----------------------------------------------------------------*/
 881
 882 void
 883 symbols_pack (void)
 884 {
 885   symbols_do (symbol_check_alias_consistency_processor, NULL);
 886
 887   symbols = xcalloc (nsyms, sizeof *symbols);
 888   symbols_do (symbol_pack_processor, NULL);
 889
 890   /* Aliases leave empty slots in symbols, so remove them.  */
 891   {
 892     int writei;
 893     int readi;
 894     int nsyms_old = nsyms;
 895     for (writei = 0, readi = 0; readi < nsyms_old; readi += 1)
 896       {
 897         if (symbols[readi] == NULL)
 898           {
 899             nsyms -= 1;
 900             ntokens -= 1;
 901           }
 902         else
 903           {
 904             symbols[writei] = symbols[readi];
 905             symbols[writei]->number = writei;
 906             if (symbols[writei]->alias)
 907               symbols[writei]->alias->number = writei;
 908             writei += 1;
 909           }
 910       }
 911   }
 912   symbols = xnrealloc (symbols, nsyms, sizeof *symbols);
 913
 914   symbols_token_translations_init ();
 915
 916   if (startsymbol->class == unknown_sym)
 917     fatal_at (startsymbol_location,
 918               _("the start symbol %s is undefined"),
 919               startsymbol->tag);
 920   else if (startsymbol->class == token_sym)
 921     fatal_at (startsymbol_location,
 922               _("the start symbol %s is a token"),
 923               startsymbol->tag);
 924 }
 925
 926
 927 /*-----------------------------------.
 928 | Set default %destructor/%printer.  |
 929 `-----------------------------------*/
 930
 931 void
 932 default_destructor_set (const char *destructor, location loc)
 933 {
 934   if (default_destructor != NULL)
 935     {
 936       complain_at (loc, _("redeclaration for default %%destructor"));
 937       complain_at (default_destructor_location, _("previous declaration"));
 938     }
 939   default_destructor = destructor;
 940   default_destructor_location = loc;
 941 }
 942
 943 void
 944 default_printer_set (const char *printer, location loc)
 945 {
 946   if (default_printer != NULL)
 947     {
 948       complain_at (loc, _("redeclaration for default %%printer"));
 949       complain_at (default_printer_location, _("previous declaration"));
 950     }
 951   default_printer = printer;
 952   default_printer_location = loc;
 953 }