src/gram.c

   1 /* Allocate input grammar variables for Bison.
   2
   3    Copyright (C) 1984, 1986, 1989, 2001, 2002 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    Bison is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    Bison is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with Bison; see the file COPYING.  If not, write to
  19    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22
  23 #include "system.h"
  24
  25 #include <quotearg.h>
  26
  27 #include "gram.h"
  28 #include "reader.h"
  29 #include "reduce.h"
  30 #include "symtab.h"
  31
  32 /* Comments for these variables are in gram.h.  */
  33
  34 item_number *ritem = NULL;
  35 unsigned int nritems = 0;
  36
  37 rule *rules = NULL;
  38 rule_number nrules = 0;
  39
  40 symbol **symbols = NULL;
  41 int nsyms = 0;
  42 int ntokens = 1;
  43 int nvars = 0;
  44
  45 symbol_number *token_translations = NULL;
  46
  47 int max_user_token_number = 256;
  48
  49 int glr_parser = 0;
  50 int pure_parser = 0;
  51
  52
  53 /*--------------------------------------------------------------.
  54 | Return true IFF the rule has a `number' smaller than NRULES.  |
  55 `--------------------------------------------------------------*/
  56
  57 bool
  58 rule_useful_p (rule *r)
  59 {
  60   return r->number < nrules;
  61 }
  62
  63
  64 /*-------------------------------------------------------------.
  65 | Return true IFF the rule has a `number' higher than NRULES.  |
  66 `-------------------------------------------------------------*/
  67
  68 bool
  69 rule_useless_p (rule *r)
  70 {
  71   return r->number >= nrules;
  72 }
  73
  74
  75 /*--------------------------------------------------------------------.
  76 | Return true IFF the rule is not flagged as useful *and* is useful.  |
  77 | In other words, it was discarded because of conflicts.              |
  78 `--------------------------------------------------------------------*/
  79
  80 bool
  81 rule_never_reduced_p (rule *r)
  82 {
  83   return !r->useful && r->number < nrules;
  84 }
  85
  86
  87 /*----------------------------------------------------------------.
  88 | Print this RULE's number and lhs on OUT.  If a PREVIOUS_LHS was |
  89 | already displayed (by a previous call for another rule), avoid  |
  90 | useless repetitions.                                            |
  91 `----------------------------------------------------------------*/
  92
  93 void
  94 rule_lhs_print (rule *r, symbol *previous_lhs, FILE *out)
  95 {
  96   fprintf (out, "  %3d ", r->number);
  97   if (previous_lhs != r->lhs)
  98     {
  99       fprintf (out, "%s:", r->lhs->tag);
 100     }
 101   else
 102     {
 103       int n;
 104       for (n = strlen (previous_lhs->tag); n > 0; --n)
 105         fputc (' ', out);
 106       fputc ('|', out);
 107     }
 108 }
 109
 110
 111 /*--------------------------------------.
 112 | Return the number of symbols in RHS.  |
 113 `--------------------------------------*/
 114
 115 int
 116 rule_rhs_length (rule *r)
 117 {
 118   int res = 0;
 119   item_number *rhsp;
 120   for (rhsp = r->rhs; *rhsp >= 0; ++rhsp)
 121     ++res;
 122   return res;
 123 }
 124
 125
 126 /*-------------------------------.
 127 | Print this rule's RHS on OUT.  |
 128 `-------------------------------*/
 129
 130 void
 131 rule_rhs_print (rule *r, FILE *out)
 132 {
 133   if (*r->rhs >= 0)
 134     {
 135       item_number *rp;
 136       for (rp = r->rhs; *rp >= 0; rp++)
 137         fprintf (out, " %s", symbols[*rp]->tag);
 138       fputc ('\n', out);
 139     }
 140   else
 141     {
 142       fprintf (out, " /* %s */\n", _("empty"));
 143     }
 144 }
 145
 146
 147 /*-------------------------.
 148 | Print this rule on OUT.  |
 149 `-------------------------*/
 150
 151 void
 152 rule_print (rule *r, FILE *out)
 153 {
 154   fprintf (out, "%s:", r->lhs->tag);
 155   rule_rhs_print (r, out);
 156 }
 157
 158
 159 /*------------------------.
 160 | Dump RITEM for traces.  |
 161 `------------------------*/
 162
 163 void
 164 ritem_print (FILE *out)
 165 {
 166   unsigned int i;
 167   fputs ("RITEM\n", out);
 168   for (i = 0; i < nritems; ++i)
 169     if (ritem[i] >= 0)
 170       fprintf (out, "  %s", symbols[ritem[i]]->tag);
 171     else
 172       fprintf (out, "  (rule %d)\n", item_number_as_rule_number (ritem[i]));
 173   fputs ("\n\n", out);
 174 }
 175
 176
 177 /*------------------------------------------.
 178 | Return the size of the longest rule RHS.  |
 179 `------------------------------------------*/
 180
 181 size_t
 182 ritem_longest_rhs (void)
 183 {
 184   int max = 0;
 185   rule_number r;
 186
 187   for (r = 0; r < nrules; ++r)
 188     {
 189       int length = rule_rhs_length (&rules[r]);
 190       if (length > max)
 191         max = length;
 192     }
 193
 194   return max;
 195 }
 196
 197
 198 /*-----------------------------------------------------------------.
 199 | Print the grammar's rules that match FILTER on OUT under TITLE.  |
 200 `-----------------------------------------------------------------*/
 201
 202 void
 203 grammar_rules_partial_print (FILE *out, const char *title,
 204                              rule_filter filter)
 205 {
 206   int r;
 207   bool first = true;
 208   symbol *previous_lhs = NULL;
 209
 210   /* rule # : LHS -> RHS */
 211   for (r = 0; r < nrules + nuseless_productions; r++)
 212     {
 213       if (filter && !filter (&rules[r]))
 214         continue;
 215       if (first)
 216         fprintf (out, "%s\n\n", title);
 217       else if (previous_lhs && previous_lhs != rules[r].lhs)
 218         fputc ('\n', out);
 219       first = false;
 220       rule_lhs_print (&rules[r], previous_lhs, out);
 221       rule_rhs_print (&rules[r], out);
 222       previous_lhs = rules[r].lhs;
 223     }
 224   if (!first)
 225     fputs ("\n\n", out);
 226 }
 227
 228
 229 /*------------------------------------------.
 230 | Print the grammar's useful rules on OUT.  |
 231 `------------------------------------------*/
 232
 233 void
 234 grammar_rules_print (FILE *out)
 235 {
 236   grammar_rules_partial_print (out, _("Grammar"), rule_useful_p);
 237 }
 238
 239
 240 /*-------------------.
 241 | Dump the grammar.  |
 242 `-------------------*/
 243
 244 void
 245 grammar_dump (FILE *out, const char *title)
 246 {
 247   fprintf (out, "%s\n\n", title);
 248   fprintf (out,
 249            "ntokens = %d, nvars = %d, nsyms = %d, nrules = %d, nritems = %d\n\n",
 250            ntokens, nvars, nsyms, nrules, nritems);
 251
 252
 253   fprintf (out, "Variables\n---------\n\n");
 254   {
 255     symbol_number i;
 256     fprintf (out, "Value  Sprec  Sassoc  Tag\n");
 257
 258     for (i = ntokens; i < nsyms; i++)
 259       fprintf (out, "%5d  %5d   %5d  %s\n",
 260                i,
 261                symbols[i]->prec, symbols[i]->assoc,
 262                symbols[i]->tag);
 263     fprintf (out, "\n\n");
 264   }
 265
 266   fprintf (out, "Rules\n-----\n\n");
 267   {
 268     rule_number i;
 269     fprintf (out, "Num (Prec, Assoc, Useful, Ritem Range) Lhs -> Rhs (Ritem range) [Num]\n");
 270     for (i = 0; i < nrules + nuseless_productions; i++)
 271       {
 272         rule *rule_i = &rules[i];
 273         item_number *r = NULL;
 274         unsigned int rhs_itemno = rule_i->rhs - ritem;
 275         unsigned int rhs_count = 0;
 276         /* Find the last RHS index in ritems. */
 277         for (r = rule_i->rhs; *r >= 0; ++r)
 278           ++rhs_count;
 279         fprintf (out, "%3d (%2d, %2d, %2d, %2u-%2u)   %2d ->",
 280                  i,
 281                  rule_i->prec ? rule_i->prec->prec : 0,
 282                  rule_i->prec ? rule_i->prec->assoc : 0,
 283                  rule_i->useful,
 284                  rhs_itemno,
 285                  rhs_itemno + rhs_count - 1,
 286                  rule_i->lhs->number);
 287         /* Dumped the RHS. */
 288         for (r = rule_i->rhs; *r >= 0; r++)
 289           fprintf (out, " %3d", *r);
 290         fprintf (out, "  [%d]\n", item_number_as_rule_number (*r));
 291       }
 292   }
 293   fprintf (out, "\n\n");
 294
 295   fprintf (out, "Rules interpreted\n-----------------\n\n");
 296   {
 297     rule_number r;
 298     for (r = 0; r < nrules + nuseless_productions; r++)
 299       {
 300         fprintf (out, "%-5d  ", r);
 301         rule_print (&rules[r], out);
 302       }
 303   }
 304   fprintf (out, "\n\n");
 305 }
 306
 307
 308 /*------------------------------------------------------------------.
 309 | Report on STDERR the rules that are not flagged USEFUL, using the |
 310 | MESSAGE (which can be `useless rule' when invoked after grammar   |
 311 | reduction, or `never reduced' after conflicts were taken into     |
 312 | account).                                                         |
 313 `------------------------------------------------------------------*/
 314
 315 void
 316 grammar_rules_never_reduced_report (const char *message)
 317 {
 318   rule_number r;
 319   for (r = 0; r < nrules ; ++r)
 320     if (!rules[r].useful)
 321       {
 322         location_print (stderr, rules[r].location);
 323         fprintf (stderr, ": %s: %s: ",
 324                  _("warning"), message);
 325         rule_print (&rules[r], stderr);
 326       }
 327 }
 328
 329 void
 330 grammar_free (void)
 331 {
 332   XFREE (ritem);
 333   free (rules);
 334   XFREE (token_translations);
 335   /* Free the symbol table data structure.  */
 336   symbols_free ();
 337   free_merger_functions ();
 338 }