src/symtab.c

   1 /* Symbol table manager for Bison.
   2
   3    Copyright (C) 1984, 1989, 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008
   4    Free Software Foundation, Inc.
   5
   6    This file is part of Bison, the GNU Compiler Compiler.
   7
   8    This program 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 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include <config.h>
  22 #include "system.h"
  23
  24 #include <hash.h>
  25 #include <quotearg.h>
  26
  27 #include "complain.h"
  28 #include "gram.h"
  29 #include "symtab.h"
  30
  31 /*------------------------.
  32 | Distinguished symbols.  |
  33 `------------------------*/
  34
  35 symbol *errtoken = NULL;
  36 symbol *undeftoken = NULL;
  37 symbol *endtoken = NULL;
  38 symbol *accept = NULL;
  39 symbol *startsymbol = NULL;
  40 location startsymbol_location;
  41
  42 /*---------------------------------------.
  43 | Default %destructor's and %printer's.  |
  44 `---------------------------------------*/
  45
  46 static code_props default_tagged_destructor = CODE_PROPS_NONE_INIT;
  47 static code_props default_tagless_destructor = CODE_PROPS_NONE_INIT;
  48 static code_props default_tagged_printer = CODE_PROPS_NONE_INIT;
  49 static code_props default_tagless_printer = CODE_PROPS_NONE_INIT;
  50
  51 /*---------------------------------.
  52 | Create a new symbol, named TAG.  |
  53 `---------------------------------*/
  54
  55 static symbol *
  56 symbol_new (uniqstr tag, location loc)
  57 {
  58   symbol *res = xmalloc (sizeof *res);
  59
  60   uniqstr_assert (tag);
  61   res->tag = tag;
  62   res->location = loc;
  63
  64   res->type_name = NULL;
  65   code_props_none_init (&res->destructor);
  66   code_props_none_init (&res->printer);
  67
  68   res->number = NUMBER_UNDEFINED;
  69   res->prec = 0;
  70   res->assoc = undef_assoc;
  71   res->user_token_number = USER_NUMBER_UNDEFINED;
  72
  73   res->alias = NULL;
  74   res->class = unknown_sym;
  75   res->declared = false;
  76
  77   if (nsyms == SYMBOL_NUMBER_MAXIMUM)
  78     fatal (_("too many symbols in input grammar (limit is %d)"),
  79            SYMBOL_NUMBER_MAXIMUM);
  80   nsyms++;
  81   return res;
  82 }
  83
  84 /*----------------------------------------.
  85 | Create a new semantic type, named TAG.  |
  86 `----------------------------------------*/
  87
  88 static semantic_type *
  89 semantic_type_new (uniqstr tag)
  90 {
  91   semantic_type *res = xmalloc (sizeof *res);
  92
  93   uniqstr_assert (tag);
  94   res->tag = tag;
  95   code_props_none_init (&res->destructor);
  96   code_props_none_init (&res->printer);
  97
  98   return res;
  99 }
 100
 101
 102 /*-----------------.
 103 | Print a symbol.  |
 104 `-----------------*/
 105
 106 #define SYMBOL_ATTR_PRINT(Attr)                         \
 107   if (s->Attr)                                          \
 108     fprintf (f, " %s { %s }", #Attr, s->Attr)
 109
 110 #define SYMBOL_CODE_PRINT(Attr)                         \
 111   if (s->Attr.code)                                     \
 112     fprintf (f, " %s { %s }", #Attr, s->Attr.code)
 113
 114 void
 115 symbol_print (symbol *s, FILE *f)
 116 {
 117   if (s)
 118     {
 119       fprintf (f, "\"%s\"", s->tag);
 120       SYMBOL_ATTR_PRINT (type_name);
 121       SYMBOL_CODE_PRINT (destructor);
 122       SYMBOL_CODE_PRINT (printer);
 123     }
 124   else
 125     fprintf (f, "<NULL>");
 126 }
 127
 128 #undef SYMBOL_ATTR_PRINT
 129 #undef SYMBOL_CODE_PRINT
 130
 131
 132 /*----------------------------------.
 133 | Whether S is a valid identifier.  |
 134 `----------------------------------*/
 135
 136 static bool
 137 is_identifier (uniqstr s)
 138 {
 139   static char const alphanum[26 + 26 + 1 + 10] =
 140     "abcdefghijklmnopqrstuvwxyz"
 141     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 142     "_"
 143     "0123456789";
 144   if (!s || ! memchr (alphanum, *s, sizeof alphanum - 10))
 145     return false;
 146   for (++s; *s; ++s)
 147     if (! memchr (alphanum, *s, sizeof alphanum))
 148       return false;
 149   return true;
 150 }
 151
 152
 153 /*-----------------------------------------------.
 154 | Get the identifier associated to this symbol.  |
 155 `-----------------------------------------------*/
 156 uniqstr
 157 symbol_id_get (symbol const *sym)
 158 {
 159   aver (sym->user_token_number != USER_NUMBER_ALIAS);
 160   if (sym->alias)
 161     sym = sym->alias;
 162   return is_identifier (sym->tag) ? sym->tag : 0;
 163 }
 164
 165
 166 /*------------------------------------------------------------------.
 167 | Complain that S's WHAT is redeclared at SECOND, and was first set |
 168 | at FIRST.                                                         |
 169 `------------------------------------------------------------------*/
 170
 171 static void
 172 symbol_redeclaration (symbol *s, const char *what, location first,
 173                       location second)
 174 {
 175   complain_at (second, _("%s redeclaration for %s"), what, s->tag);
 176   complain_at (first, _("previous declaration"));
 177 }
 178
 179 static void
 180 semantic_type_redeclaration (semantic_type *s, const char *what, location first,
 181                              location second)
 182 {
 183   complain_at (second, _("%s redeclaration for <%s>"), what, s->tag);
 184   complain_at (first, _("previous declaration"));
 185 }
 186
 187
 188 /*-----------------------------------------------------------------.
 189 | Set the TYPE_NAME associated with SYM.  Does nothing if passed 0 |
 190 | as TYPE_NAME.                                                    |
 191 `-----------------------------------------------------------------*/
 192
 193 void
 194 symbol_type_set (symbol *sym, uniqstr type_name, location loc)
 195 {
 196   if (type_name)
 197     {
 198       if (sym->type_name)
 199         symbol_redeclaration (sym, "%type", sym->type_location, loc);
 200       uniqstr_assert (type_name);
 201       sym->type_name = type_name;
 202       sym->type_location = loc;
 203     }
 204 }
 205
 206 /*-----------------------------------.
 207 | Get the CLASS associated with SYM. |
 208 `-----------------------------------*/
 209
 210 const char *
 211 symbol_class_get_string (symbol *sym)
 212 {
 213   if (sym->class)
 214     {
 215       if (sym->class == token_sym)
 216         return "terminal";
 217       else if (sym->class == nterm_sym)
 218         return "nonterminal";
 219     }
 220   return "unknown";
 221 }
 222
 223
 224 /*-----------------------------------------.
 225 | Set the DESTRUCTOR associated with SYM.  |
 226 `-----------------------------------------*/
 227
 228 void
 229 symbol_destructor_set (symbol *sym, code_props const *destructor)
 230 {
 231   if (sym->destructor.code)
 232     symbol_redeclaration (sym, "%destructor", sym->destructor.location,
 233                           destructor->location);
 234   sym->destructor = *destructor;
 235 }
 236
 237 /*------------------------------------------.
 238 | Set the DESTRUCTOR associated with TYPE.  |
 239 `------------------------------------------*/
 240
 241 void
 242 semantic_type_destructor_set (semantic_type *type,
 243                               code_props const *destructor)
 244 {
 245   if (type->destructor.code)
 246     semantic_type_redeclaration (type, "%destructor",
 247                                  type->destructor.location,
 248                                  destructor->location);
 249   type->destructor = *destructor;
 250 }
 251
 252 /*---------------------------------------.
 253 | Get the computed %destructor for SYM.  |
 254 `---------------------------------------*/
 255
 256 code_props const *
 257 symbol_destructor_get (symbol const *sym)
 258 {
 259   /* Per-symbol %destructor.  */
 260   if (sym->destructor.code)
 261     return &sym->destructor;
 262
 263   /* Per-type %destructor.  */
 264   if (sym->type_name)
 265     {
 266       code_props const *destructor =
 267         &semantic_type_get (sym->type_name)->destructor;
 268       if (destructor->code)
 269         return destructor;
 270     }
 271
 272   /* Apply default %destructor's only to user-defined symbols.  */
 273   if (sym->tag[0] == '$' || sym == errtoken)
 274     return &code_props_none;
 275
 276   if (sym->type_name)
 277     return &default_tagged_destructor;
 278   return &default_tagless_destructor;
 279 }
 280
 281 /*--------------------------------------.
 282 | Set the PRINTER associated with SYM.  |
 283 `--------------------------------------*/
 284
 285 void
 286 symbol_printer_set (symbol *sym, code_props const *printer)
 287 {
 288   if (sym->printer.code)
 289     symbol_redeclaration (sym, "%printer",
 290                           sym->printer.location, printer->location);
 291   sym->printer = *printer;
 292 }
 293
 294 /*---------------------------------------.
 295 | Set the PRINTER associated with TYPE.  |
 296 `---------------------------------------*/
 297
 298 void
 299 semantic_type_printer_set (semantic_type *type, code_props const *printer)
 300 {
 301   if (type->printer.code)
 302     semantic_type_redeclaration (type, "%printer",
 303                                  type->printer.location, printer->location);
 304   type->printer = *printer;
 305 }
 306
 307 /*------------------------------------.
 308 | Get the computed %printer for SYM.  |
 309 `------------------------------------*/
 310
 311 code_props const *
 312 symbol_printer_get (symbol const *sym)
 313 {
 314   /* Per-symbol %printer.  */
 315   if (sym->printer.code)
 316     return &sym->printer;
 317
 318   /* Per-type %printer.  */
 319   if (sym->type_name)
 320     {
 321       code_props const *printer = &semantic_type_get (sym->type_name)->printer;
 322       if (printer->code)
 323         return printer;
 324     }
 325
 326   /* Apply the default %printer only to user-defined symbols.  */
 327   if (sym->tag[0] == '$' || sym == errtoken)
 328     return &code_props_none;
 329
 330   if (sym->type_name)
 331     return &default_tagged_printer;
 332   return &default_tagless_printer;
 333 }
 334
 335 /*-----------------------------------------------------------------.
 336 | Set the PRECEDENCE associated with SYM.  Does nothing if invoked |
 337 | with UNDEF_ASSOC as ASSOC.                                       |
 338 `-----------------------------------------------------------------*/
 339
 340 void
 341 symbol_precedence_set (symbol *sym, int prec, assoc a, location loc)
 342 {
 343   if (a != undef_assoc)
 344     {
 345       if (sym->prec != 0)
 346         symbol_redeclaration (sym, assoc_to_string (a), sym->prec_location,
 347                               loc);
 348       sym->prec = prec;
 349       sym->assoc = a;
 350       sym->prec_location = loc;
 351     }
 352
 353   /* Only terminals have a precedence. */
 354   symbol_class_set (sym, token_sym, loc, false);
 355 }
 356
 357
 358 /*------------------------------------.
 359 | Set the CLASS associated with SYM.  |
 360 `------------------------------------*/
 361
 362 void
 363 symbol_class_set (symbol *sym, symbol_class class, location loc, bool declaring)
 364 {
 365   if (sym->class != unknown_sym && sym->class != class)
 366     {
 367       complain_at (loc, _("symbol %s redefined"), sym->tag);
 368       sym->declared = false;
 369     }
 370
 371   if (class == nterm_sym && sym->class != nterm_sym)
 372     sym->number = nvars++;
 373   else if (class == token_sym && sym->number == NUMBER_UNDEFINED)
 374     sym->number = ntokens++;
 375
 376   sym->class = class;
 377
 378   if (declaring)
 379     {
 380       if (sym->declared)
 381         warn_at (loc, _("symbol %s redeclared"), sym->tag);
 382       sym->declared = true;
 383     }
 384 }
 385
 386
 387 /*------------------------------------------------.
 388 | Set the USER_TOKEN_NUMBER associated with SYM.  |
 389 `------------------------------------------------*/
 390
 391 void
 392 symbol_user_token_number_set (symbol *sym, int user_token_number, location loc)
 393 {
 394   int *user_token_numberp;
 395
 396   if (sym->user_token_number != USER_NUMBER_ALIAS)
 397     user_token_numberp = &sym->user_token_number;
 398   else
 399     user_token_numberp = &sym->alias->user_token_number;
 400   if (*user_token_numberp != USER_NUMBER_UNDEFINED
 401       && *user_token_numberp != user_token_number)
 402     complain_at (loc, _("redefining user token number of %s"), sym->tag);
 403
 404   *user_token_numberp = user_token_number;
 405   /* User defined $end token? */
 406   if (user_token_number == 0)
 407     {
 408       endtoken = sym;
 409       endtoken->number = 0;
 410       /* It is always mapped to 0, so it was already counted in
 411          NTOKENS.  */
 412       --ntokens;
 413     }
 414 }
 415
 416
 417 /*----------------------------------------------------------.
 418 | If SYM is not defined, report an error, and consider it a |
 419 | nonterminal.                                              |
 420 `----------------------------------------------------------*/
 421
 422 static inline bool
 423 symbol_check_defined (symbol *sym)
 424 {
 425   if (sym->class == unknown_sym)
 426     {
 427       complain_at
 428         (sym->location,
 429          _("symbol %s is used, but is not defined as a token and has no rules"),
 430          sym->tag);
 431       sym->class = nterm_sym;
 432       sym->number = nvars++;
 433     }
 434
 435   return true;
 436 }
 437
 438 static bool
 439 symbol_check_defined_processor (void *sym, void *null ATTRIBUTE_UNUSED)
 440 {
 441   return symbol_check_defined (sym);
 442 }
 443
 444
 445 /*------------------------------------------------------------------.
 446 | Declare the new symbol SYM.  Make it an alias of SYMVAL, and type |
 447 | SYMVAL with SYM's type.                                           |
 448 `------------------------------------------------------------------*/
 449
 450 void
 451 symbol_make_alias (symbol *sym, symbol *symval, location loc)
 452 {
 453   if (symval->alias)
 454     warn_at (loc, _("symbol `%s' used more than once as a literal string"),
 455              symval->tag);
 456   else if (sym->alias)
 457     warn_at (loc, _("symbol `%s' given more than one literal string"),
 458              sym->tag);
 459   else
 460     {
 461       symval->class = token_sym;
 462       symval->user_token_number = sym->user_token_number;
 463       sym->user_token_number = USER_NUMBER_ALIAS;
 464       symval->alias = sym;
 465       sym->alias = symval;
 466       symval->number = sym->number;
 467       symbol_type_set (symval, sym->type_name, loc);
 468     }
 469 }
 470
 471
 472 /*---------------------------------------------------------.
 473 | Check that THIS, and its alias, have same precedence and |
 474 | associativity.                                           |
 475 `---------------------------------------------------------*/
 476
 477 static inline void
 478 symbol_check_alias_consistency (symbol *this)
 479 {
 480   symbol *alias = this;
 481   symbol *orig  = this->alias;
 482
 483   /* Check only those that _are_ the aliases.  */
 484   if (!(this->alias && this->user_token_number == USER_NUMBER_ALIAS))
 485     return;
 486
 487   if (orig->type_name != alias->type_name)
 488     {
 489       if (orig->type_name)
 490         symbol_type_set (alias, orig->type_name, orig->type_location);
 491       else
 492         symbol_type_set (orig, alias->type_name, alias->type_location);
 493     }
 494
 495
 496   if (orig->destructor.code || alias->destructor.code)
 497     {
 498       if (orig->destructor.code)
 499         symbol_destructor_set (alias, &orig->destructor);
 500       else
 501         symbol_destructor_set (orig, &alias->destructor);
 502     }
 503
 504   if (orig->printer.code || alias->printer.code)
 505     {
 506       if (orig->printer.code)
 507         symbol_printer_set (alias, &orig->printer);
 508       else
 509         symbol_printer_set (orig, &alias->printer);
 510     }
 511
 512   if (alias->prec || orig->prec)
 513     {
 514       if (orig->prec)
 515         symbol_precedence_set (alias, orig->prec, orig->assoc,
 516                                orig->prec_location);
 517       else
 518         symbol_precedence_set (orig, alias->prec, alias->assoc,
 519                                alias->prec_location);
 520     }
 521 }
 522
 523 static bool
 524 symbol_check_alias_consistency_processor (void *this,
 525                                           void *null ATTRIBUTE_UNUSED)
 526 {
 527   symbol_check_alias_consistency (this);
 528   return true;
 529 }
 530
 531
 532 /*-------------------------------------------------------------------.
 533 | Assign a symbol number, and write the definition of the token name |
 534 | into FDEFINES.  Put in SYMBOLS.                                    |
 535 `-------------------------------------------------------------------*/
 536
 537 static inline bool
 538 symbol_pack (symbol *this)
 539 {
 540   if (this->class == nterm_sym)
 541     {
 542       this->number += ntokens;
 543     }
 544   else if (this->alias)
 545     {
 546       /* This symbol and its alias are a single token defn.
 547          Allocate a tokno, and assign to both check agreement of
 548          prec and assoc fields and make both the same */
 549       if (this->number == NUMBER_UNDEFINED)
 550         {
 551           if (this == endtoken || this->alias == endtoken)
 552             this->number = this->alias->number = 0;
 553           else
 554             {
 555               aver (this->alias->number != NUMBER_UNDEFINED);
 556               this->number = this->alias->number;
 557             }
 558         }
 559       /* Do not do processing below for USER_NUMBER_ALIASes.  */
 560       if (this->user_token_number == USER_NUMBER_ALIAS)
 561         return true;
 562     }
 563   else /* this->class == token_sym */
 564     aver (this->number != NUMBER_UNDEFINED);
 565
 566   symbols[this->number] = this;
 567   return true;
 568 }
 569
 570 static bool
 571 symbol_pack_processor (void *this, void *null ATTRIBUTE_UNUSED)
 572 {
 573   return symbol_pack (this);
 574 }
 575
 576
 577
 578
 579 /*--------------------------------------------------.
 580 | Put THIS in TOKEN_TRANSLATIONS if it is a token.  |
 581 `--------------------------------------------------*/
 582
 583 static inline bool
 584 symbol_translation (symbol *this)
 585 {
 586   /* Non-terminal? */
 587   if (this->class == token_sym
 588       && this->user_token_number != USER_NUMBER_ALIAS)
 589     {
 590       /* A token which translation has already been set? */
 591       if (token_translations[this->user_token_number] != undeftoken->number)
 592         complain_at (this->location,
 593                      _("tokens %s and %s both assigned number %d"),
 594                      symbols[token_translations[this->user_token_number]]->tag,
 595                      this->tag, this->user_token_number);
 596
 597       token_translations[this->user_token_number] = this->number;
 598     }
 599
 600   return true;
 601 }
 602
 603 static bool
 604 symbol_translation_processor (void *this, void *null ATTRIBUTE_UNUSED)
 605 {
 606   return symbol_translation (this);
 607 }
 608
 609
 610 /*---------------------------------------.
 611 | Symbol and semantic type hash tables.  |
 612 `---------------------------------------*/
 613
 614 /* Initial capacity of symbol and semantic type hash table.  */
 615 #define HT_INITIAL_CAPACITY 257
 616
 617 static struct hash_table *symbol_table = NULL;
 618 static struct hash_table *semantic_type_table = NULL;
 619
 620 static inline bool
 621 hash_compare_symbol (const symbol *m1, const symbol *m2)
 622 {
 623   /* Since tags are unique, we can compare the pointers themselves.  */
 624   return UNIQSTR_EQ (m1->tag, m2->tag);
 625 }
 626
 627 static inline bool
 628 hash_compare_semantic_type (const semantic_type *m1, const semantic_type *m2)
 629 {
 630   /* Since names are unique, we can compare the pointers themselves.  */
 631   return UNIQSTR_EQ (m1->tag, m2->tag);
 632 }
 633
 634 static bool
 635 hash_symbol_comparator (void const *m1, void const *m2)
 636 {
 637   return hash_compare_symbol (m1, m2);
 638 }
 639
 640 static bool
 641 hash_semantic_type_comparator (void const *m1, void const *m2)
 642 {
 643   return hash_compare_semantic_type (m1, m2);
 644 }
 645
 646 static inline size_t
 647 hash_symbol (const symbol *m, size_t tablesize)
 648 {
 649   /* Since tags are unique, we can hash the pointer itself.  */
 650   return ((uintptr_t) m->tag) % tablesize;
 651 }
 652
 653 static inline size_t
 654 hash_semantic_type (const semantic_type *m, size_t tablesize)
 655 {
 656   /* Since names are unique, we can hash the pointer itself.  */
 657   return ((uintptr_t) m->tag) % tablesize;
 658 }
 659
 660 static size_t
 661 hash_symbol_hasher (void const *m, size_t tablesize)
 662 {
 663   return hash_symbol (m, tablesize);
 664 }
 665
 666 static size_t
 667 hash_semantic_type_hasher (void const *m, size_t tablesize)
 668 {
 669   return hash_semantic_type (m, tablesize);
 670 }
 671
 672 /*-------------------------------.
 673 | Create the symbol hash table.  |
 674 `-------------------------------*/
 675
 676 void
 677 symbols_new (void)
 678 {
 679   symbol_table = hash_initialize (HT_INITIAL_CAPACITY,
 680                                   NULL,
 681                                   hash_symbol_hasher,
 682                                   hash_symbol_comparator,
 683                                   free);
 684   semantic_type_table = hash_initialize (HT_INITIAL_CAPACITY,
 685                                          NULL,
 686                                          hash_semantic_type_hasher,
 687                                          hash_semantic_type_comparator,
 688                                          free);
 689 }
 690
 691
 692 /*----------------------------------------------------------------.
 693 | Find the symbol named KEY, and return it.  If it does not exist |
 694 | yet, create it.                                                 |
 695 `----------------------------------------------------------------*/
 696
 697 symbol *
 698 symbol_from_uniqstr (const uniqstr key, location loc)
 699 {
 700   symbol probe;
 701   symbol *entry;
 702
 703   probe.tag = key;
 704   entry = hash_lookup (symbol_table, &probe);
 705
 706   if (!entry)
 707     {
 708       /* First insertion in the hash. */
 709       entry = symbol_new (key, loc);
 710       hash_insert (symbol_table, entry);
 711     }
 712   return entry;
 713 }
 714
 715
 716 /*-----------------------------------------------------------------------.
 717 | Find the semantic type named KEY, and return it.  If it does not exist |
 718 | yet, create it.                                                        |
 719 `-----------------------------------------------------------------------*/
 720
 721 semantic_type *
 722 semantic_type_from_uniqstr (const uniqstr key)
 723 {
 724   semantic_type probe;
 725   semantic_type *entry;
 726
 727   probe.tag = key;
 728   entry = hash_lookup (semantic_type_table, &probe);
 729
 730   if (!entry)
 731     {
 732       /* First insertion in the hash. */
 733       entry = semantic_type_new (key);
 734       hash_insert (semantic_type_table, entry);
 735     }
 736   return entry;
 737 }
 738
 739
 740 /*----------------------------------------------------------------.
 741 | Find the symbol named KEY, and return it.  If it does not exist |
 742 | yet, create it.                                                 |
 743 `----------------------------------------------------------------*/
 744
 745 symbol *
 746 symbol_get (const char *key, location loc)
 747 {
 748   return symbol_from_uniqstr (uniqstr_new (key), loc);
 749 }
 750
 751
 752 /*-----------------------------------------------------------------------.
 753 | Find the semantic type named KEY, and return it.  If it does not exist |
 754 | yet, create it.                                                        |
 755 `-----------------------------------------------------------------------*/
 756
 757 semantic_type *
 758 semantic_type_get (const char *key)
 759 {
 760   return semantic_type_from_uniqstr (uniqstr_new (key));
 761 }
 762
 763
 764 /*------------------------------------------------------------------.
 765 | Generate a dummy nonterminal, whose name cannot conflict with the |
 766 | user's names.                                                     |
 767 `------------------------------------------------------------------*/
 768
 769 symbol *
 770 dummy_symbol_get (location loc)
 771 {
 772   /* Incremented for each generated symbol.  */
 773   static int dummy_count = 0;
 774   static char buf[256];
 775
 776   symbol *sym;
 777
 778   sprintf (buf, "$@%d", ++dummy_count);
 779   sym = symbol_get (buf, loc);
 780   sym->class = nterm_sym;
 781   sym->number = nvars++;
 782   return sym;
 783 }
 784
 785 bool
 786 symbol_is_dummy (const symbol *sym)
 787 {
 788   return sym->tag[0] == '@' || (sym->tag[0] == '$' && sym->tag[1] == '@');
 789 }
 790
 791 /*-------------------.
 792 | Free the symbols.  |
 793 `-------------------*/
 794
 795 void
 796 symbols_free (void)
 797 {
 798   hash_free (symbol_table);
 799   hash_free (semantic_type_table);
 800   free (symbols);
 801 }
 802
 803
 804 /*---------------------------------------------------------------.
 805 | Look for undefined symbols, report an error, and consider them |
 806 | terminals.                                                     |
 807 `---------------------------------------------------------------*/
 808
 809 static void
 810 symbols_do (Hash_processor processor, void *processor_data)
 811 {
 812   hash_do_for_each (symbol_table, processor, processor_data);
 813 }
 814
 815
 816 /*--------------------------------------------------------------.
 817 | Check that all the symbols are defined.  Report any undefined |
 818 | symbols and consider them nonterminals.                       |
 819 `--------------------------------------------------------------*/
 820
 821 void
 822 symbols_check_defined (void)
 823 {
 824   symbols_do (symbol_check_defined_processor, NULL);
 825 }
 826
 827 /*------------------------------------------------------------------.
 828 | Set TOKEN_TRANSLATIONS.  Check that no two symbols share the same |
 829 | number.                                                           |
 830 `------------------------------------------------------------------*/
 831
 832 static void
 833 symbols_token_translations_init (void)
 834 {
 835   bool num_256_available_p = true;
 836   int i;
 837
 838   /* Find the highest user token number, and whether 256, the POSIX
 839      preferred user token number for the error token, is used.  */
 840   max_user_token_number = 0;
 841   for (i = 0; i < ntokens; ++i)
 842     {
 843       symbol *this = symbols[i];
 844       if (this->user_token_number != USER_NUMBER_UNDEFINED)
 845         {
 846           if (this->user_token_number > max_user_token_number)
 847             max_user_token_number = this->user_token_number;
 848           if (this->user_token_number == 256)
 849             num_256_available_p = false;
 850         }
 851     }
 852
 853   /* If 256 is not used, assign it to error, to follow POSIX.  */
 854   if (num_256_available_p
 855       && errtoken->user_token_number == USER_NUMBER_UNDEFINED)
 856     errtoken->user_token_number = 256;
 857
 858   /* Set the missing user numbers. */
 859   if (max_user_token_number < 256)
 860     max_user_token_number = 256;
 861
 862   for (i = 0; i < ntokens; ++i)
 863     {
 864       symbol *this = symbols[i];
 865       if (this->user_token_number == USER_NUMBER_UNDEFINED)
 866         this->user_token_number = ++max_user_token_number;
 867       if (this->user_token_number > max_user_token_number)
 868         max_user_token_number = this->user_token_number;
 869     }
 870
 871   token_translations = xnmalloc (max_user_token_number + 1,
 872                                  sizeof *token_translations);
 873
 874   /* Initialize all entries for literal tokens to the internal token
 875      number for $undefined, which represents all invalid inputs.  */
 876   for (i = 0; i < max_user_token_number + 1; i++)
 877     token_translations[i] = undeftoken->number;
 878   symbols_do (symbol_translation_processor, NULL);
 879 }
 880
 881
 882 /*----------------------------------------------------------------.
 883 | Assign symbol numbers, and write definition of token names into |
 884 | FDEFINES.  Set up vectors SYMBOL_TABLE, TAGS of symbols.        |
 885 `----------------------------------------------------------------*/
 886
 887 void
 888 symbols_pack (void)
 889 {
 890   symbols_do (symbol_check_alias_consistency_processor, NULL);
 891
 892   symbols = xcalloc (nsyms, sizeof *symbols);
 893   symbols_do (symbol_pack_processor, NULL);
 894
 895   /* Aliases leave empty slots in symbols, so remove them.  */
 896   {
 897     int writei;
 898     int readi;
 899     int nsyms_old = nsyms;
 900     for (writei = 0, readi = 0; readi < nsyms_old; readi += 1)
 901       {
 902         if (symbols[readi] == NULL)
 903           {
 904             nsyms -= 1;
 905             ntokens -= 1;
 906           }
 907         else
 908           {
 909             symbols[writei] = symbols[readi];
 910             symbols[writei]->number = writei;
 911             if (symbols[writei]->alias)
 912               symbols[writei]->alias->number = writei;
 913             writei += 1;
 914           }
 915       }
 916   }
 917   symbols = xnrealloc (symbols, nsyms, sizeof *symbols);
 918
 919   symbols_token_translations_init ();
 920
 921   if (startsymbol->class == unknown_sym)
 922     fatal_at (startsymbol_location,
 923               _("the start symbol %s is undefined"),
 924               startsymbol->tag);
 925   else if (startsymbol->class == token_sym)
 926     fatal_at (startsymbol_location,
 927               _("the start symbol %s is a token"),
 928               startsymbol->tag);
 929 }
 930
 931
 932 /*--------------------------------------------------.
 933 | Set default tagged/tagless %destructor/%printer.  |
 934 `--------------------------------------------------*/
 935
 936 void
 937 default_tagged_destructor_set (code_props const *destructor)
 938 {
 939   if (default_tagged_destructor.code)
 940     {
 941       complain_at (destructor->location,
 942                    _("redeclaration for default tagged %%destructor"));
 943       complain_at (default_tagged_destructor.location,
 944                    _("previous declaration"));
 945     }
 946   default_tagged_destructor = *destructor;
 947 }
 948
 949 void
 950 default_tagless_destructor_set (code_props const *destructor)
 951 {
 952   if (default_tagless_destructor.code)
 953     {
 954       complain_at (destructor->location,
 955                    _("redeclaration for default tagless %%destructor"));
 956       complain_at (default_tagless_destructor.location,
 957                    _("previous declaration"));
 958     }
 959   default_tagless_destructor = *destructor;
 960 }
 961
 962 void
 963 default_tagged_printer_set (code_props const *printer)
 964 {
 965   if (default_tagged_printer.code)
 966     {
 967       complain_at (printer->location,
 968                    _("redeclaration for default tagged %%printer"));
 969       complain_at (default_tagged_printer.location,
 970                    _("previous declaration"));
 971     }
 972   default_tagged_printer = *printer;
 973 }
 974
 975 void
 976 default_tagless_printer_set (code_props const *printer)
 977 {
 978   if (default_tagless_printer.code)
 979     {
 980       complain_at (printer->location,
 981                    _("redeclaration for default tagless %%printer"));
 982       complain_at (default_tagless_printer.location,
 983                    _("previous declaration"));
 984     }
 985   default_tagless_printer = *printer;
 986 }