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    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 <quotearg.h>
  25
  26 #include "gram.h"
  27 #include "reader.h"
  28 #include "reduce.h"
  29 #include "symtab.h"
  30
  31 /* Comments for these variables are in gram.h.  */
  32
  33 item_number *ritem = NULL;
  34 unsigned int nritems = 0;
  35
  36 rule *rules = NULL;
  37 rule_number nrules = 0;
  38
  39 symbol **symbols = NULL;
  40 int nsyms = 0;
  41 int ntokens = 1;
  42 int nvars = 0;
  43
  44 symbol_number *token_translations = NULL;
  45
  46 int max_user_token_number = 256;
  47
  48 /*--------------------------------------------------------------.
  49 | Return true IFF the rule has a `number' smaller than NRULES.  |
  50 `--------------------------------------------------------------*/
  51
  52 bool
  53 rule_useful_p (rule *r)
  54 {
  55   return r->number < nrules;
  56 }
  57
  58
  59 /*-------------------------------------------------------------.
  60 | Return true IFF the rule has a `number' higher than NRULES.  |
  61 `-------------------------------------------------------------*/
  62
  63 bool
  64 rule_useless_p (rule *r)
  65 {
  66   return !rule_useful_p (r);
  67 }
  68
  69
  70 /*--------------------------------------------------------------------.
  71 | Return true IFF the rule is not flagged as useful *and* is useful.  |
  72 | In other words, it was discarded because of conflicts.              |
  73 `--------------------------------------------------------------------*/
  74
  75 bool
  76 rule_never_reduced_p (rule *r)
  77 {
  78   return !r->useful && rule_useful_p (r);
  79 }
  80
  81
  82 /*----------------------------------------------------------------.
  83 | Print this RULE's number and lhs on OUT.  If a PREVIOUS_LHS was |
  84 | already displayed (by a previous call for another rule), avoid  |
  85 | useless repetitions.                                            |
  86 `----------------------------------------------------------------*/
  87
  88 void
  89 rule_lhs_print (rule *r, symbol *previous_lhs, FILE *out)
  90 {
  91   fprintf (out, "  %3d ", r->number);
  92   if (previous_lhs != r->lhs)
  93     {
  94       fprintf (out, "%s:", r->lhs->tag);
  95     }
  96   else
  97     {
  98       int n;
  99       for (n = strlen (previous_lhs->tag); n > 0; --n)
 100         fputc (' ', out);
 101       fputc ('|', out);
 102     }
 103 }
 104
 105
 106 /*--------------------------------------.
 107 | Return the number of symbols in RHS.  |
 108 `--------------------------------------*/
 109
 110 int
 111 rule_rhs_length (rule *r)
 112 {
 113   int res = 0;
 114   item_number *rhsp;
 115   for (rhsp = r->rhs; *rhsp >= 0; ++rhsp)
 116     ++res;
 117   return res;
 118 }
 119
 120
 121 /*-------------------------------.
 122 | Print this rule's RHS on OUT.  |
 123 `-------------------------------*/
 124
 125 void
 126 rule_rhs_print (rule *r, FILE *out)
 127 {
 128   if (*r->rhs >= 0)
 129     {
 130       item_number *rp;
 131       for (rp = r->rhs; *rp >= 0; rp++)
 132         fprintf (out, " %s", symbols[*rp]->tag);
 133       fputc ('\n', out);
 134     }
 135   else
 136     {
 137       fprintf (out, " /* %s */\n", _("empty"));
 138     }
 139 }
 140
 141
 142 /*-------------------------.
 143 | Print this rule on OUT.  |
 144 `-------------------------*/
 145
 146 void
 147 rule_print (rule *r, FILE *out)
 148 {
 149   fprintf (out, "%s:", r->lhs->tag);
 150   rule_rhs_print (r, out);
 151 }
 152
 153
 154 /*------------------------.
 155 | Dump RITEM for traces.  |
 156 `------------------------*/
 157
 158 void
 159 ritem_print (FILE *out)
 160 {
 161   unsigned int i;
 162   fputs ("RITEM\n", out);
 163   for (i = 0; i < nritems; ++i)
 164     if (ritem[i] >= 0)
 165       fprintf (out, "  %s", symbols[ritem[i]]->tag);
 166     else
 167       fprintf (out, "  (rule %d)\n", item_number_as_rule_number (ritem[i]));
 168   fputs ("\n\n", out);
 169 }
 170
 171
 172 /*------------------------------------------.
 173 | Return the size of the longest rule RHS.  |
 174 `------------------------------------------*/
 175
 176 size_t
 177 ritem_longest_rhs (void)
 178 {
 179   int max = 0;
 180   rule_number r;
 181
 182   for (r = 0; r < nrules; ++r)
 183     {
 184       int length = rule_rhs_length (&rules[r]);
 185       if (length > max)
 186         max = length;
 187     }
 188
 189   return max;
 190 }
 191
 192
 193 /*-----------------------------------------------------------------.
 194 | Print the grammar's rules that match FILTER on OUT under TITLE.  |
 195 `-----------------------------------------------------------------*/
 196
 197 void
 198 grammar_rules_partial_print (FILE *out, const char *title,
 199                              rule_filter filter)
 200 {
 201   rule_number r;
 202   bool first = true;
 203   symbol *previous_lhs = NULL;
 204
 205   /* rule # : LHS -> RHS */
 206   for (r = 0; r < nrules + nuseless_productions; r++)
 207     {
 208       if (filter && !filter (&rules[r]))
 209         continue;
 210       if (first)
 211         fprintf (out, "%s\n\n", title);
 212       else if (previous_lhs && previous_lhs != rules[r].lhs)
 213         fputc ('\n', out);
 214       first = false;
 215       rule_lhs_print (&rules[r], previous_lhs, out);
 216       rule_rhs_print (&rules[r], out);
 217       previous_lhs = rules[r].lhs;
 218     }
 219   if (!first)
 220     fputs ("\n\n", out);
 221 }
 222
 223
 224 /*------------------------------------------.
 225 | Print the grammar's useful rules on OUT.  |
 226 `------------------------------------------*/
 227
 228 void
 229 grammar_rules_print (FILE *out)
 230 {
 231   grammar_rules_partial_print (out, _("Grammar"), rule_useful_p);
 232 }
 233
 234
 235 /*-------------------.
 236 | Dump the grammar.  |
 237 `-------------------*/
 238
 239 void
 240 grammar_dump (FILE *out, const char *title)
 241 {
 242   fprintf (out, "%s\n\n", title);
 243   fprintf (out,
 244            "ntokens = %d, nvars = %d, nsyms = %d, nrules = %d, nritems = %d\n\n",
 245            ntokens, nvars, nsyms, nrules, nritems);
 246
 247
 248   fprintf (out, "Variables\n---------\n\n");
 249   {
 250     symbol_number i;
 251     fprintf (out, "Value  Sprec  Sassoc  Tag\n");
 252
 253     for (i = ntokens; i < nsyms; i++)
 254       fprintf (out, "%5d  %5d   %5d  %s\n",
 255                i,
 256                symbols[i]->prec, symbols[i]->assoc,
 257                symbols[i]->tag);
 258     fprintf (out, "\n\n");
 259   }
 260
 261   fprintf (out, "Rules\n-----\n\n");
 262   {
 263     rule_number i;
 264     fprintf (out, "Num (Prec, Assoc, Useful, Ritem Range) Lhs -> Rhs (Ritem range) [Num]\n");
 265     for (i = 0; i < nrules + nuseless_productions; i++)
 266       {
 267         rule *rule_i = &rules[i];
 268         item_number *rp = NULL;
 269         unsigned int rhs_itemno = rule_i->rhs - ritem;
 270         unsigned int rhs_count = 0;
 271         /* Find the last RHS index in ritems. */
 272         for (rp = rule_i->rhs; *rp >= 0; ++rp)
 273           ++rhs_count;
 274         fprintf (out, "%3d (%2d, %2d, %2d, %2u-%2u)   %2d ->",
 275                  i,
 276                  rule_i->prec ? rule_i->prec->prec : 0,
 277                  rule_i->prec ? rule_i->prec->assoc : 0,
 278                  rule_i->useful,
 279                  rhs_itemno,
 280                  rhs_itemno + rhs_count - 1,
 281                  rule_i->lhs->number);
 282         /* Dumped the RHS. */
 283         for (rp = rule_i->rhs; *rp >= 0; rp++)
 284           fprintf (out, " %3d", *rp);
 285         fprintf (out, "  [%d]\n", item_number_as_rule_number (*rp));
 286       }
 287   }
 288   fprintf (out, "\n\n");
 289
 290   fprintf (out, "Rules interpreted\n-----------------\n\n");
 291   {
 292     rule_number r;
 293     for (r = 0; r < nrules + nuseless_productions; r++)
 294       {
 295         fprintf (out, "%-5d  ", r);
 296         rule_print (&rules[r], out);
 297       }
 298   }
 299   fprintf (out, "\n\n");
 300 }
 301
 302
 303 /*------------------------------------------------------------------.
 304 | Report on STDERR the rules that are not flagged USEFUL, using the |
 305 | MESSAGE (which can be `useless rule' when invoked after grammar   |
 306 | reduction, or `never reduced' after conflicts were taken into     |
 307 | account).                                                         |
 308 `------------------------------------------------------------------*/
 309
 310 void
 311 grammar_rules_never_reduced_report (const char *message)
 312 {
 313   rule_number r;
 314   for (r = 0; r < nrules ; ++r)
 315     if (!rules[r].useful)
 316       {
 317         location_print (stderr, rules[r].location);
 318         fprintf (stderr, ": %s: %s: ", _("warning"), message);
 319         rule_print (&rules[r], stderr);
 320       }
 321 }
 322
 323 void
 324 grammar_free (void)
 325 {
 326   if (ritem)
 327     free (ritem - 1);
 328   free (rules);
 329   free (token_translations);
 330   /* Free the symbol table data structure.  */
 331   symbols_free ();
 332   free_merger_functions ();
 333 }