src/gram.c

   1 /* Allocate input grammar variables for Bison.
   2
   3    Copyright (C) 1984, 1986, 1989, 2001-2003, 2005-2015, 2018-2021 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 <https://www.gnu.org/licenses/>.  */
  20
  21 #include <config.h>
  22 #include "system.h"
  23
  24 #include "complain.h"
  25 #include "getargs.h"
  26 #include "glyphs.h"
  27 #include "gram.h"
  28 #include "print-xml.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 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 nnterms = 0;
  45
  46 symbol_number *token_translations = NULL;
  47
  48 int max_code = 256;
  49
  50 int required_version = 0;
  51
  52 void
  53 item_print (item_number *item, rule const *previous_rule, FILE *out)
  54 {
  55   rule const *r = item_rule (item);
  56   rule_lhs_print (r, previous_rule ? previous_rule->lhs : NULL, out);
  57
  58   if (0 <= *r->rhs)
  59     {
  60       // Non-empty rhs.
  61       for (item_number *sp = r->rhs; sp < item; sp++)
  62         fprintf (out, " %s", symbols[*sp]->tag);
  63       fprintf (out, " %s", dot);
  64       for (item_number *sp = item; 0 <= *sp; ++sp)
  65         fprintf (out, " %s", symbols[*sp]->tag);
  66     }
  67   else
  68     fprintf (out, " %s %s", empty, dot);
  69 }
  70
  71
  72 bool
  73 rule_useful_in_grammar_p (rule const *r)
  74 {
  75   return r->number < nrules;
  76 }
  77
  78 bool
  79 rule_useless_in_grammar_p (rule const *r)
  80 {
  81   return !rule_useful_in_grammar_p (r);
  82 }
  83
  84 bool
  85 rule_useless_in_parser_p (rule const *r)
  86 {
  87   return !r->useful && rule_useful_in_grammar_p (r);
  88 }
  89
  90 bool
  91 rule_useless_chain_p (rule const *r)
  92 {
  93   return rule_rhs_length (r) == 1 && !r->action;
  94 }
  95
  96 void
  97 rule_lhs_print (rule const *r, sym_content const *previous_lhs, FILE *out)
  98 {
  99   fprintf (out, "  %3d ", r->number);
 100   if (previous_lhs != r->lhs)
 101     fprintf (out, "%s:", r->lhs->symbol->tag);
 102   else
 103     fprintf (out, "%*s|", (int) strlen (previous_lhs->symbol->tag), "");
 104 }
 105
 106 void
 107 rule_lhs_print_xml (rule const *r, FILE *out, int level)
 108 {
 109   xml_printf (out, level, "<lhs>%s</lhs>", r->lhs->symbol->tag);
 110 }
 111
 112 size_t
 113 rule_rhs_length (rule const *r)
 114 {
 115   size_t res = 0;
 116   for (item_number *rhsp = r->rhs; 0 <= *rhsp; ++rhsp)
 117     ++res;
 118   return res;
 119 }
 120
 121 void
 122 rule_rhs_print (rule const *r, FILE *out)
 123 {
 124   if (0 <= *r->rhs)
 125     for (item_number *rhsp = r->rhs; 0 <= *rhsp; ++rhsp)
 126       fprintf (out, " %s", symbols[*rhsp]->tag);
 127   else
 128     fprintf (out, " %s", empty);
 129 }
 130
 131 static void
 132 rule_rhs_print_xml (rule const *r, FILE *out, int level)
 133 {
 134   if (*r->rhs >= 0)
 135     {
 136       xml_puts (out, level, "<rhs>");
 137       for (item_number *rhsp = r->rhs; 0 <= *rhsp; ++rhsp)
 138         xml_printf (out, level + 1, "<symbol>%s</symbol>",
 139                     xml_escape (symbols[*rhsp]->tag));
 140       xml_puts (out, level, "</rhs>");
 141     }
 142   else
 143     {
 144       xml_puts (out, level, "<rhs>");
 145       xml_puts (out, level + 1, "<empty/>");
 146       xml_puts (out, level, "</rhs>");
 147     }
 148 }
 149
 150 void
 151 rule_print (rule const *r, rule const *prev_rule, FILE *out)
 152 {
 153   rule_lhs_print (r, prev_rule ? prev_rule->lhs : NULL, out);
 154   rule_rhs_print (r, out);
 155 }
 156
 157 void
 158 ritem_print (FILE *out)
 159 {
 160   fputs ("RITEM\n", out);
 161   bool first = true;
 162   for (int i = 0; i < nritems; ++i)
 163     {
 164       if (first)
 165         {
 166           fprintf (out, "  %d: ", i);
 167           first = false;
 168         }
 169       if (ritem[i] >= 0)
 170         fprintf (out, "  %s", symbols[ritem[i]]->tag);
 171       else
 172         {
 173           fprintf (out, "  (rule %d)\n", item_number_as_rule_number (ritem[i]));
 174           first = true;
 175         }
 176     }
 177   fputs ("\n\n", out);
 178 }
 179
 180 size_t
 181 ritem_longest_rhs (void)
 182 {
 183   int max = 0;
 184   for (rule_number r = 0; r < nrules; ++r)
 185     {
 186       size_t length = rule_rhs_length (&rules[r]);
 187       if (length > max)
 188         max = length;
 189     }
 190
 191   return max;
 192 }
 193
 194 void
 195 grammar_rules_partial_print (FILE *out, const char *title,
 196                              rule_filter filter)
 197 {
 198   bool first = true;
 199   rule *previous_rule = NULL;
 200
 201   /* rule # : LHS -> RHS */
 202   for (rule_number r = 0; r < nrules + nuseless_productions; r++)
 203     {
 204       if (filter && !filter (&rules[r]))
 205         continue;
 206       if (first)
 207         fprintf (out, "%s\n\n", title);
 208       else if (previous_rule && previous_rule->lhs != rules[r].lhs)
 209         putc ('\n', out);
 210       first = false;
 211       rule_print (&rules[r], previous_rule, out);
 212       putc ('\n', out);
 213       previous_rule = &rules[r];
 214     }
 215   if (!first)
 216     fputs ("\n\n", out);
 217 }
 218
 219 void
 220 grammar_rules_print (FILE *out)
 221 {
 222   grammar_rules_partial_print (out, _("Grammar"), rule_useful_in_grammar_p);
 223 }
 224
 225 void
 226 grammar_rules_print_xml (FILE *out, int level)
 227 {
 228   bool first = true;
 229
 230   for (rule_number r = 0; r < nrules + nuseless_productions; r++)
 231     {
 232       if (first)
 233         xml_puts (out, level + 1, "<rules>");
 234       first = false;
 235       {
 236         char const *usefulness
 237           = rule_useless_in_grammar_p (&rules[r]) ? "useless-in-grammar"
 238           : rule_useless_in_parser_p (&rules[r])  ? "useless-in-parser"
 239           :                                         "useful";
 240         xml_indent (out, level + 2);
 241         fprintf (out, "<rule number=\"%d\" usefulness=\"%s\"",
 242                  rules[r].number, usefulness);
 243         if (rules[r].precsym)
 244           fprintf (out, " percent_prec=\"%s\"",
 245                    xml_escape (rules[r].precsym->symbol->tag));
 246         fputs (">\n", out);
 247       }
 248       rule_lhs_print_xml (&rules[r], out, level + 3);
 249       rule_rhs_print_xml (&rules[r], out, level + 3);
 250       xml_puts (out, level + 2, "</rule>");
 251     }
 252   if (!first)
 253     xml_puts (out, level + 1, "</rules>");
 254   else
 255    xml_puts (out, level + 1, "<rules/>");
 256 }
 257
 258 static void
 259 section (FILE *out, const char *s)
 260 {
 261   fprintf (out, "%s\n", s);
 262   for (int i = strlen (s); 0 < i; --i)
 263     putc ('-', out);
 264   putc ('\n', out);
 265   putc ('\n', out);
 266 }
 267
 268 void
 269 grammar_dump (FILE *out, const char *title)
 270 {
 271   fprintf (out, "%s\n\n", title);
 272   fprintf (out,
 273            "ntokens = %d, nnterms = %d, nsyms = %d, nrules = %d, nritems = %d\n\n",
 274            ntokens, nnterms, nsyms, nrules, nritems);
 275
 276   section (out, "Tokens");
 277   {
 278     fprintf (out, "Value  Sprec  Sassoc  Tag\n");
 279
 280     for (symbol_number i = 0; i < ntokens; i++)
 281       fprintf (out, "%5d  %5d   %5d  %s\n",
 282                i,
 283                symbols[i]->content->prec, symbols[i]->content->assoc,
 284                symbols[i]->tag);
 285     fprintf (out, "\n\n");
 286   }
 287
 288   section (out, "Nonterminals");
 289   {
 290     fprintf (out, "Value  Tag\n");
 291
 292     for (symbol_number i = ntokens; i < nsyms; i++)
 293       fprintf (out, "%5d  %s\n",
 294                i, symbols[i]->tag);
 295     fprintf (out, "\n\n");
 296   }
 297
 298   section (out, "Rules");
 299   {
 300     fprintf (out,
 301              "Num (Prec, Assoc, Useful, UselessChain) Lhs"
 302              " -> (Ritem Range) Rhs\n");
 303     for (rule_number i = 0; i < nrules + nuseless_productions; ++i)
 304       {
 305         rule const *rule_i = &rules[i];
 306         int const rhs_itemno = rule_i->rhs - ritem;
 307         int length = rule_rhs_length (rule_i);
 308         aver (item_number_as_rule_number (rule_i->rhs[length]) == i);
 309         fprintf (out, "%3d (%2d, %2d, %2s, %2s)   %2d -> (%2u-%2u)",
 310                  i,
 311                  rule_i->prec ? rule_i->prec->prec : 0,
 312                  rule_i->prec ? rule_i->prec->assoc : 0,
 313                  rule_i->useful ? "t" : "f",
 314                  rule_useless_chain_p (rule_i) ? "t" : "f",
 315                  rule_i->lhs->number,
 316                  rhs_itemno, rhs_itemno + length - 1);
 317         /* Dumped the RHS. */
 318         for (item_number *rhsp = rule_i->rhs; 0 <= *rhsp; ++rhsp)
 319           fprintf (out, " %3d", *rhsp);
 320         putc ('\n', out);
 321       }
 322   }
 323   fprintf (out, "\n\n");
 324
 325   section (out, "Rules interpreted");
 326   for (rule_number r = 0; r < nrules + nuseless_productions; ++r)
 327     {
 328       fprintf (out, "%-5d  %s:", r, rules[r].lhs->symbol->tag);
 329       rule_rhs_print (&rules[r], out);
 330       putc ('\n', out);
 331     }
 332   fprintf (out, "\n\n");
 333 }
 334
 335 void
 336 grammar_rules_useless_report (const char *message)
 337 {
 338   for (rule_number r = 0; r < nrules; ++r)
 339     /* Don't complain about rules whose LHS is useless, we already
 340        complained about it.  */
 341     if (!reduce_nonterminal_useless_in_grammar (rules[r].lhs)
 342         && !rules[r].useful)
 343       complain (&rules[r].location, Wother, "%s", message);
 344 }
 345
 346 void
 347 grammar_free (void)
 348 {
 349   if (ritem)
 350     free (ritem - 1);
 351   free (rules);
 352   free (token_translations);
 353   /* Free the symbol table data structure.  */
 354   symbols_free ();
 355   free_merger_functions ();
 356 }