src/gram.c

   1 /* Allocate input grammar variables for Bison.
   2
   3    Copyright (C) 1984, 1986, 1989, 2001, 2002, 2003, 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 <quotearg.h>
  27
  28 #include "gram.h"
  29 #include "reader.h"
  30 #include "reduce.h"
  31 #include "symtab.h"
  32
  33 /* Comments for these variables are in gram.h.  */
  34
  35 item_number *ritem = NULL;
  36 unsigned int nritems = 0;
  37
  38 rule *rules = NULL;
  39 rule_number nrules = 0;
  40
  41 symbol **symbols = NULL;
  42 int nsyms = 0;
  43 int ntokens = 1;
  44 int nvars = 0;
  45
  46 symbol_number *token_translations = NULL;
  47
  48 int max_user_token_number = 256;
  49
  50 /*--------------------------------------------------------------.
  51 | Return true IFF the rule has a `number' smaller than NRULES.  |
  52 `--------------------------------------------------------------*/
  53
  54 bool
  55 rule_useful_p (rule *r)
  56 {
  57   return r->number < nrules;
  58 }
  59
  60
  61 /*-------------------------------------------------------------.
  62 | Return true IFF the rule has a `number' higher than NRULES.  |
  63 `-------------------------------------------------------------*/
  64
  65 bool
  66 rule_useless_p (rule *r)
  67 {
  68   return !rule_useful_p (r);
  69 }
  70
  71
  72 /*--------------------------------------------------------------------.
  73 | Return true IFF the rule is not flagged as useful *and* is useful.  |
  74 | In other words, it was discarded because of conflicts.              |
  75 `--------------------------------------------------------------------*/
  76
  77 bool
  78 rule_never_reduced_p (rule *r)
  79 {
  80   return !r->useful && rule_useful_p (r);
  81 }
  82
  83
  84 /*----------------------------------------------------------------.
  85 | Print this RULE's number and lhs on OUT.  If a PREVIOUS_LHS was |
  86 | already displayed (by a previous call for another rule), avoid  |
  87 | useless repetitions.                                            |
  88 `----------------------------------------------------------------*/
  89
  90 void
  91 rule_lhs_print (rule *r, symbol *previous_lhs, FILE *out)
  92 {
  93   fprintf (out, "  %3d ", r->number);
  94   if (previous_lhs != r->lhs)
  95     {
  96       fprintf (out, "%s:", r->lhs->tag);
  97     }
  98   else
  99     {
 100       int n;
 101       for (n = strlen (previous_lhs->tag); n > 0; --n)
 102         fputc (' ', out);
 103       fputc ('|', out);
 104     }
 105 }
 106
 107
 108 /*--------------------------------------.
 109 | Return the number of symbols in RHS.  |
 110 `--------------------------------------*/
 111
 112 int
 113 rule_rhs_length (rule *r)
 114 {
 115   int res = 0;
 116   item_number *rhsp;
 117   for (rhsp = r->rhs; *rhsp >= 0; ++rhsp)
 118     ++res;
 119   return res;
 120 }
 121
 122
 123 /*-------------------------------.
 124 | Print this rule's RHS on OUT.  |
 125 `-------------------------------*/
 126
 127 void
 128 rule_rhs_print (rule *r, FILE *out)
 129 {
 130   if (*r->rhs >= 0)
 131     {
 132       item_number *rp;
 133       for (rp = r->rhs; *rp >= 0; rp++)
 134         fprintf (out, " %s", symbols[*rp]->tag);
 135       fputc ('\n', out);
 136     }
 137   else
 138     {
 139       fprintf (out, " /* %s */\n", _("empty"));
 140     }
 141 }
 142
 143
 144 /*-------------------------.
 145 | Print this rule on OUT.  |
 146 `-------------------------*/
 147
 148 void
 149 rule_print (rule *r, FILE *out)
 150 {
 151   fprintf (out, "%s:", r->lhs->tag);
 152   rule_rhs_print (r, out);
 153 }
 154
 155
 156 /*------------------------.
 157 | Dump RITEM for traces.  |
 158 `------------------------*/
 159
 160 void
 161 ritem_print (FILE *out)
 162 {
 163   unsigned int i;
 164   fputs ("RITEM\n", out);
 165   for (i = 0; i < nritems; ++i)
 166     if (ritem[i] >= 0)
 167       fprintf (out, "  %s", symbols[ritem[i]]->tag);
 168     else
 169       fprintf (out, "  (rule %d)\n", item_number_as_rule_number (ritem[i]));
 170   fputs ("\n\n", out);
 171 }
 172
 173
 174 /*------------------------------------------.
 175 | Return the size of the longest rule RHS.  |
 176 `------------------------------------------*/
 177
 178 size_t
 179 ritem_longest_rhs (void)
 180 {
 181   int max = 0;
 182   rule_number r;
 183
 184   for (r = 0; r < nrules; ++r)
 185     {
 186       int length = rule_rhs_length (&rules[r]);
 187       if (length > max)
 188         max = length;
 189     }
 190
 191   return max;
 192 }
 193
 194
 195 /*-----------------------------------------------------------------.
 196 | Print the grammar's rules that match FILTER on OUT under TITLE.  |
 197 `-----------------------------------------------------------------*/
 198
 199 void
 200 grammar_rules_partial_print (FILE *out, const char *title,
 201                              rule_filter filter)
 202 {
 203   rule_number r;
 204   bool first = true;
 205   symbol *previous_lhs = NULL;
 206
 207   /* rule # : LHS -> RHS */
 208   for (r = 0; r < nrules + nuseless_productions; r++)
 209     {
 210       if (filter && !filter (&rules[r]))
 211         continue;
 212       if (first)
 213         fprintf (out, "%s\n\n", title);
 214       else if (previous_lhs && previous_lhs != rules[r].lhs)
 215         fputc ('\n', out);
 216       first = false;
 217       rule_lhs_print (&rules[r], previous_lhs, out);
 218       rule_rhs_print (&rules[r], out);
 219       previous_lhs = rules[r].lhs;
 220     }
 221   if (!first)
 222     fputs ("\n\n", out);
 223 }
 224
 225
 226 /*------------------------------------------.
 227 | Print the grammar's useful rules on OUT.  |
 228 `------------------------------------------*/
 229
 230 void
 231 grammar_rules_print (FILE *out)
 232 {
 233   grammar_rules_partial_print (out, _("Grammar"), rule_useful_p);
 234 }
 235
 236
 237 /*-------------------.
 238 | Dump the grammar.  |
 239 `-------------------*/
 240
 241 void
 242 grammar_dump (FILE *out, const char *title)
 243 {
 244   fprintf (out, "%s\n\n", title);
 245   fprintf (out,
 246            "ntokens = %d, nvars = %d, nsyms = %d, nrules = %d, nritems = %d\n\n",
 247            ntokens, nvars, nsyms, nrules, nritems);
 248
 249
 250   fprintf (out, "Variables\n---------\n\n");
 251   {
 252     symbol_number i;
 253     fprintf (out, "Value  Sprec  Sassoc  Tag\n");
 254
 255     for (i = ntokens; i < nsyms; i++)
 256       fprintf (out, "%5d  %5d   %5d  %s\n",
 257                i,
 258                symbols[i]->prec, symbols[i]->assoc,
 259                symbols[i]->tag);
 260     fprintf (out, "\n\n");
 261   }
 262
 263   fprintf (out, "Rules\n-----\n\n");
 264   {
 265     rule_number i;
 266     fprintf (out, "Num (Prec, Assoc, Useful, Ritem Range) Lhs -> Rhs (Ritem range) [Num]\n");
 267     for (i = 0; i < nrules + nuseless_productions; i++)
 268       {
 269         rule *rule_i = &rules[i];
 270         item_number *rp = NULL;
 271         unsigned int rhs_itemno = rule_i->rhs - ritem;
 272         unsigned int rhs_count = 0;
 273         /* Find the last RHS index in ritems. */
 274         for (rp = rule_i->rhs; *rp >= 0; ++rp)
 275           ++rhs_count;
 276         fprintf (out, "%3d (%2d, %2d, %2d, %2u-%2u)   %2d ->",
 277                  i,
 278                  rule_i->prec ? rule_i->prec->prec : 0,
 279                  rule_i->prec ? rule_i->prec->assoc : 0,
 280                  rule_i->useful,
 281                  rhs_itemno,
 282                  rhs_itemno + rhs_count - 1,
 283                  rule_i->lhs->number);
 284         /* Dumped the RHS. */
 285         for (rp = rule_i->rhs; *rp >= 0; rp++)
 286           fprintf (out, " %3d", *rp);
 287         fprintf (out, "  [%d]\n", item_number_as_rule_number (*rp));
 288       }
 289   }
 290   fprintf (out, "\n\n");
 291
 292   fprintf (out, "Rules interpreted\n-----------------\n\n");
 293   {
 294     rule_number r;
 295     for (r = 0; r < nrules + nuseless_productions; r++)
 296       {
 297         fprintf (out, "%-5d  ", r);
 298         rule_print (&rules[r], out);
 299       }
 300   }
 301   fprintf (out, "\n\n");
 302 }
 303
 304
 305 /*------------------------------------------------------------------.
 306 | Report on STDERR the rules that are not flagged USEFUL, using the |
 307 | MESSAGE (which can be `useless rule' when invoked after grammar   |
 308 | reduction, or `never reduced' after conflicts were taken into     |
 309 | account).                                                         |
 310 `------------------------------------------------------------------*/
 311
 312 void
 313 grammar_rules_never_reduced_report (const char *message)
 314 {
 315   rule_number r;
 316   for (r = 0; r < nrules ; ++r)
 317     if (!rules[r].useful)
 318       {
 319         location_print (stderr, rules[r].location);
 320         fprintf (stderr, ": %s: %s: ", _("warning"), message);
 321         rule_print (&rules[r], stderr);
 322       }
 323 }
 324
 325 void
 326 grammar_free (void)
 327 {
 328   if (ritem)
 329     free (ritem - 1);
 330   free (rules);
 331   free (token_translations);
 332   /* Free the symbol table data structure.  */
 333   symbols_free ();
 334   free_merger_functions ();
 335 }