Add new files for IELR and canonical LR implementation.

[bison.git] / src / reduce.c

diff --git a/src/reduce.c b/src/reduce.c
index b4b8dc34cfd4ee120707c6ebbde486cb2658e024..596a26bc8204d451e3f635a141377cac78cdfed5 100644 (file)
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -1,22 +1,22 @@
 /* Grammar reduction for Bison.
 /* Grammar reduction for Bison.

-   Copyright 1988, 1989, 2000, 2001  Free Software Foundation, Inc.
+
+   Copyright (C) 1988, 1989, 2000, 2001, 2002, 2003, 2005, 2006,
+   2007, 2008 Free Software Foundation, Inc.

 
    This file is part of Bison, the GNU Compiler Compiler.
 
 
    This file is part of Bison, the GNU Compiler Compiler.
 

-   Bison is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by
    it under the terms of the GNU General Public License as published by

-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.

 
 

-   Bison is distributed in the hope that it will be useful,
+   This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License

-   along with Bison; see the file COPYING.  If not, write to
-   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 
 
 /* Reduce the grammar: Find and eliminate unreachable terminals,
 
 
 /* Reduce the grammar: Find and eliminate unreachable terminals,


@@ -25,65 +25,38 @@
 /* Don't eliminate unreachable terminals: They may be used by the
    user's parser.  */
 
 /* Don't eliminate unreachable terminals: They may be used by the
    user's parser.  */
 

+#include <config.h>

 #include "system.h"
 #include "system.h"

-#include "getargs.h"
+
+#include <bitset.h>
+#include <quotearg.h>
+
+#include "complain.h"

 #include "files.h"
 #include "files.h"

+#include "getargs.h"

 #include "gram.h"
 #include "gram.h"

-#include "complain.h"
-#include "reduce.h"
+#include "print-xml.h"

 #include "reader.h"
 #include "reader.h"

-#include "getargs.h"
+#include "reduce.h"
+#include "symtab.h"

 
 

-typedef unsigned *BSet;
-typedef short *rule;
+/* Set of all nonterminals which are not useless.  */
+static bitset N;

 
 

+/* Set of all rules which have no useless nonterminals in their RHS.  */
+static bitset P;

 
 

-/* N is set of all nonterminals which are not useless.  P is set of
-   all rules which have no useless nonterminals in their RHS.  V is
-   the set of all accessible symbols.  */
+/* Set of all accessible symbols.  */
+static bitset V;

 
 

-static BSet N, P, V, V1;
+/* Set of symbols used to define rule precedence (so they are
+   `useless', but no warning should be issued).  */
+static bitset V1;

 
 

-static int nuseful_productions;
-static int nuseless_productions;
+static rule_number nuseful_productions;
+rule_number nuseless_productions;

 static int nuseful_nonterminals;
 static int nuseful_nonterminals;

-static int nuseless_nonterminals;
-\f
-static bool
-bits_equal (BSet L, BSet R, int n)
-{
-  int i;
-
-  for (i = n - 1; i >= 0; i--)
-    if (L[i] != R[i])
-      return FALSE;
-  return TRUE;
-}
-
-
-static int
-nbits (unsigned i)
-{
-  int count = 0;
-
-  while (i != 0)
-    {
-      i ^= (i & ((unsigned) (-(int) i)));
-      ++count;
-    }
-  return count;
-}
-
-
-static int
-bits_size (BSet S, int n)
-{
-  int i, count = 0;
-
-  for (i = n - 1; i >= 0; i--)
-    count += nbits (S[i]);
-  return count;
-}
+symbol_number nuseless_nonterminals;

 \f
 /*-------------------------------------------------------------------.
 | Another way to do this would be with a set for each production and |
 \f
 /*-------------------------------------------------------------------.
 | Another way to do this would be with a set for each production and |


@@ -92,19 +65,17 @@ bits_size (BSet S, int n)
 `-------------------------------------------------------------------*/
 
 static bool
 `-------------------------------------------------------------------*/
 
 static bool

-useful_production (int i, BSet N0)
+useful_production (rule_number r, bitset N0)

 {
 {

-  rule r;
-  short n;
+  item_number *rhsp;

 
   /* A production is useful if all of the nonterminals in its appear
      in the set of useful nonterminals.  */
 
 
   /* A production is useful if all of the nonterminals in its appear
      in the set of useful nonterminals.  */
 

-  for (r = &ritem[rule_table[i].rhs]; *r > 0; r++)
-    if (ISVAR (n = *r))
-      if (!BITISSET (N0, n - ntokens))
-       return FALSE;
-  return TRUE;
+  for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+    if (ISVAR (*rhsp) && !bitset_test (N0, *rhsp - ntokens))
+      return false;
+  return true;

 }
 
 
 }
 
 


@@ -115,13 +86,14 @@ useful_production (int i, BSet N0)
 static void
 useless_nonterminals (void)
 {
 static void
 useless_nonterminals (void)
 {

-  BSet Np, Ns;
-  int i;
+  bitset Np, Ns;
+  rule_number r;

 
   /* N is set as built.  Np is set being built this iteration. P is
      set of all productions which have a RHS all in N.  */
 
 
   /* N is set as built.  Np is set being built this iteration. P is
      set of all productions which have a RHS all in N.  */
 

-  Np = XCALLOC (unsigned, WORDSIZE (nvars));
+  Np = bitset_create (nvars, BITSET_FIXED);
+

 
   /* The set being computed is a set of nonterminals which can derive
      the empty string or strings consisting of all terminals. At each
 
   /* The set being computed is a set of nonterminals which can derive
      the empty string or strings consisting of all terminals. At each


@@ -141,26 +113,21 @@ useless_nonterminals (void)
 
   while (1)
     {
 
   while (1)
     {

-      for (i = WORDSIZE (nvars) - 1; i >= 0; i--)
-       Np[i] = N[i];
-      for (i = 1; i <= nrules; i++)
-       {
-         if (!BITISSET (P, i))
-           {
-             if (useful_production (i, N))
-               {
-                 SETBIT (Np, rule_table[i].lhs - ntokens);
-                 SETBIT (P, i);
-               }
-           }
-       }
-      if (bits_equal (N, Np, WORDSIZE (nvars)))
+      bitset_copy (Np, N);
+      for (r = 0; r < nrules; r++)
+       if (!bitset_test (P, r)
+           && useful_production (r, N))
+         {
+           bitset_set (Np, rules[r].lhs->number - ntokens);
+           bitset_set (P, r);
+         }
+      if (bitset_equal_p (N, Np))

        break;
       Ns = Np;
       Np = N;
       N = Ns;
     }
        break;
       Ns = Np;
       Np = N;
       N = Ns;
     }

-  XFREE (N);
+  bitset_free (N);

   N = Np;
 }
 
   N = Np;
 }
 


@@ -168,10 +135,7 @@ useless_nonterminals (void)
 static void
 inaccessable_symbols (void)
 {
 static void
 inaccessable_symbols (void)
 {

-  BSet Vp, Vs, Pp;
-  int i;
-  short t;
-  rule r;
+  bitset Vp, Vs, Pp;

 
   /* Find out which productions are reachable and which symbols are
      used.  Starting with an empty set of productions and a set of
 
   /* Find out which productions are reachable and which symbols are
      used.  Starting with an empty set of productions and a set of


@@ -196,31 +160,32 @@ inaccessable_symbols (void)
      terminals are printed (if running in verbose mode) so that the
      user can know.  */
 
      terminals are printed (if running in verbose mode) so that the
      user can know.  */
 

-  Vp = XCALLOC (unsigned, WORDSIZE (nsyms));
-  Pp = XCALLOC (unsigned, WORDSIZE (nrules + 1));
+  Vp = bitset_create (nsyms, BITSET_FIXED);
+  Pp = bitset_create (nrules, BITSET_FIXED);

 
   /* If the start symbol isn't useful, then nothing will be useful. */
 
   /* If the start symbol isn't useful, then nothing will be useful. */

-  if (BITISSET (N, start_symbol - ntokens))
+  if (bitset_test (N, accept->number - ntokens))

     {
     {

-      SETBIT (V, start_symbol);
+      bitset_set (V, accept->number);

 
       while (1)
        {
 
       while (1)
        {

-         for (i = WORDSIZE (nsyms) - 1; i >= 0; i--)
-           Vp[i] = V[i];
-         for (i = 1; i <= nrules; i++)
+         rule_number r;
+         bitset_copy (Vp, V);
+         for (r = 0; r < nrules; r++)

            {
            {

-             if (!BITISSET (Pp, i)
-                 && BITISSET (P, i)
-                 && BITISSET (V, rule_table[i].lhs))
+             if (!bitset_test (Pp, r)
+                 && bitset_test (P, r)
+                 && bitset_test (V, rules[r].lhs->number))

                {
                {

-                 for (r = &ritem[rule_table[i].rhs]; *r >= 0; r++)
-                   if (ISTOKEN (t = *r) || BITISSET (N, t - ntokens))
-                     SETBIT (Vp, t);
-                 SETBIT (Pp, i);
+                 item_number *rhsp;
+                 for (rhsp = rules[r].rhs; *rhsp >= 0; rhsp++)
+                   if (ISTOKEN (*rhsp) || bitset_test (N, *rhsp - ntokens))
+                     bitset_set (Vp, *rhsp);
+                 bitset_set (Pp, r);

                }
            }
                }
            }

-         if (bits_equal (V, Vp, WORDSIZE (nsyms)))
+         if (bitset_equal_p (V, Vp))

            break;
          Vs = Vp;
          Vp = V;
            break;
          Vs = Vp;
          Vp = V;


@@ -228,253 +193,187 @@ inaccessable_symbols (void)
        }
     }
 
        }
     }
 

-  XFREE (V);
+  bitset_free (V);

   V = Vp;
 
   /* Tokens 0, 1, and 2 are internal to Bison.  Consider them useful. */
   V = Vp;
 
   /* Tokens 0, 1, and 2 are internal to Bison.  Consider them useful. */

-  SETBIT (V, 0);               /* end-of-input token */
-  SETBIT (V, 1);               /* error token */
-  SETBIT (V, 2);               /* some undefined token */
+  bitset_set (V, endtoken->number);            /* end-of-input token */
+  bitset_set (V, errtoken->number);            /* error token */
+  bitset_set (V, undeftoken->number);          /* some undefined token */

 
 

-  XFREE (P);
+  bitset_free (P);

   P = Pp;
 
   P = Pp;
 

-  nuseful_productions = bits_size (P, WORDSIZE (nrules + 1));
+  nuseful_productions = bitset_count (P);

   nuseless_productions = nrules - nuseful_productions;
 
   nuseful_nonterminals = 0;
   nuseless_productions = nrules - nuseful_productions;
 
   nuseful_nonterminals = 0;

-  for (i = ntokens; i < nsyms; i++)
-    if (BITISSET (V, i))
-      nuseful_nonterminals++;
+  {
+    symbol_number i;
+    for (i = ntokens; i < nsyms; i++)
+      if (bitset_test (V, i))
+       nuseful_nonterminals++;
+  }

   nuseless_nonterminals = nvars - nuseful_nonterminals;
 
   /* A token that was used in %prec should not be warned about.  */
   nuseless_nonterminals = nvars - nuseful_nonterminals;
 
   /* A token that was used in %prec should not be warned about.  */

-  for (i = 1; i < nrules; i++)
-    if (rule_table[i].precsym != 0)
-      SETBIT (V1, rule_table[i].precsym);
+  {
+    rule_number r;
+    for (r = 0; r < nrules; ++r)
+      if (rules[r].precsym != 0)
+       bitset_set (V1, rules[r].precsym->number);
+  }

 }
 
 }
 

+
+/*-------------------------------------------------------------------.
+| Put the useless productions at the end of RULES, and adjust NRULES |
+| accordingly.                                                       |
+`-------------------------------------------------------------------*/
+

 static void
 reduce_grammar_tables (void)
 {
 static void
 reduce_grammar_tables (void)
 {

-/* This is turned off because we would need to change the numbers
-   in the case statements in the actions file.  */
-#if 0
-  /* remove useless productions */
-  if (nuseless_productions > 0)
-    {
-      short np, pn, ni, pi;
-
-      np = 0;
-      ni = 0;
-      for (pn = 1; pn <= nrules; pn++)
-       {
-         if (BITISSET (P, pn))
-           {
-             np++;
-             if (pn != np)
-               {
-                 rule_table[np].lhs = rule_table[pn].lhs;
-                 rline[np] = rline[pn];
-                 rule_table[np].prec = rule_table[pn].prec;
-                 rule_table[np].assoc = rule_table[pn].assoc;
-                 rule_table[np].rhs = rule_table[pn].rhs;
-                 if (rule_table[np].rhs != ni)
-                   {
-                     pi = rule_table[np].rhs;
-                     rule_table[np].rhs = ni;
-                     while (ritem[pi] >= 0)
-                       ritem[ni++] = ritem[pi++];
-                     ritem[ni++] = -np;
-                   }
-               }
-             else
-               {
-                 while (ritem[ni++] >= 0);
-               }
-           }
-       }
-      ritem[ni] = 0;
-      nrules -= nuseless_productions;
-      nitems = ni;
-
-      /* Is it worth it to reduce the amount of memory for the
-         grammar? Probably not.  */
-
-    }
-#endif /* 0 */
-  /* Disable useless productions,
-     since they may contain useless nonterms
-     that would get mapped below to -1 and confuse everyone.  */
-  if (nuseless_productions > 0)
-    {
-      int pn;
-
-      for (pn = 1; pn <= nrules; pn++)
-       {
-         if (!BITISSET (P, pn))
-           {
-             rule_table[pn].lhs = -1;
-           }
-       }
-    }
-
-  /* remove useless symbols */
-  if (nuseless_nonterminals > 0)
-    {
-
-      int i, n;
-/*      short  j; JF unused */
-      short *nontermmap;
-      rule r;
-
-      /* Create a map of nonterminal number to new nonterminal
-        number. -1 in the map means it was useless and is being
-        eliminated.  */
-
-      nontermmap = XCALLOC (short, nvars) - ntokens;
-      for (i = ntokens; i < nsyms; i++)
-       nontermmap[i] = -1;
-
-      n = ntokens;
-      for (i = ntokens; i < nsyms; i++)
-       if (BITISSET (V, i))
-         nontermmap[i] = n++;
-
-      /* Shuffle elements of tables indexed by symbol number.  */
-
-      for (i = ntokens; i < nsyms; i++)
-       {
-         n = nontermmap[i];
-         if (n >= 0)
-           {
-             sassoc[n] = sassoc[i];
-             sprec[n] = sprec[i];
-             tags[n] = tags[i];
-           }
-       }
-
-      /* Replace all symbol numbers in valid data structures.  */
+  /* Report and flag useless productions.  */
+  {
+    rule_number r;
+    for (r = 0; r < nrules; r++)
+      rules[r].useful = bitset_test (P, r);
+    grammar_rules_useless_report (_("rule useless in grammar"));
+  }
+
+  /* Map the nonterminals to their new index: useful first, useless
+     afterwards.  Kept for later report.  */
+  {
+    int useful = 0;
+    int useless = nrules - nuseless_productions;
+    rule *rules_sorted = xnmalloc (nrules, sizeof *rules_sorted);
+    rule_number r;
+    for (r = 0; r < nrules; ++r)
+      rules_sorted[rules[r].useful ? useful++ : useless++] = rules[r];
+    free (rules);
+    rules = rules_sorted;
+
+    /* Renumber the rules markers in RITEMS.  */
+    for (r = 0; r < nrules; ++r)
+      {
+       item_number *rhsp = rules[r].rhs;
+       for (/* Nothing. */; *rhsp >= 0; ++rhsp)
+         /* Nothing. */;
+       *rhsp = rule_number_as_item_number (r);
+       rules[r].number = r;
+      }
+    nrules -= nuseless_productions;
+  }
+
+  /* Adjust NRITEMS.  */
+  {
+    rule_number r;
+    int length;
+    for (r = nrules; r < nrules + nuseless_productions; ++r)
+      {
+       length = rule_rhs_length (&rules[r]);
+       nritems -= length + 1;
+      }
+  }
+}

 
 

-      for (i = 1; i <= nrules; i++)
-       {
-         /* Ignore the rules disabled above.  */
-         if (rule_table[i].lhs >= 0)
-           rule_table[i].lhs = nontermmap[rule_table[i].lhs];
-         if (ISVAR (rule_table[i].precsym))
-           /* Can this happen?  */
-           rule_table[i].precsym = nontermmap[rule_table[i].precsym];
-       }

 
 

-      for (r = ritem; *r; r++)
-       if (ISVAR (*r))
-         *r = nontermmap[*r];
+/*------------------------------.
+| Remove useless nonterminals.  |
+`------------------------------*/

 
 

-      start_symbol = nontermmap[start_symbol];
+static void
+nonterminals_reduce (void)
+{
+  symbol_number i, n;

 
 

-      nsyms -= nuseless_nonterminals;
-      nvars -= nuseless_nonterminals;
+  /* Map the nonterminals to their new index: useful first, useless
+     afterwards.  Kept for later report.  */

 
 

-      free (&nontermmap[ntokens]);
-    }
+  symbol_number *nontermmap = xnmalloc (nvars, sizeof *nontermmap);
+  n = ntokens;
+  for (i = ntokens; i < nsyms; i++)
+    if (bitset_test (V, i))
+      nontermmap[i - ntokens] = n++;
+  for (i = ntokens; i < nsyms; i++)
+    if (!bitset_test (V, i))
+      {
+       nontermmap[i - ntokens] = n++;
+       warn_at (symbols[i]->location, _("nonterminal useless in grammar: %s"),
+                symbols[i]->tag);
+      }
+
+
+  /* Shuffle elements of tables indexed by symbol number.  */
+  {
+    symbol **symbols_sorted = xnmalloc (nvars, sizeof *symbols_sorted);
+
+    for (i = ntokens; i < nsyms; i++)
+      symbols[i]->number = nontermmap[i - ntokens];
+    for (i = ntokens; i < nsyms; i++)
+      symbols_sorted[nontermmap[i - ntokens] - ntokens] = symbols[i];
+    for (i = ntokens; i < nsyms; i++)
+      symbols[i] = symbols_sorted[i - ntokens];
+    free (symbols_sorted);
+  }
+
+  {
+    rule_number r;
+    for (r = 0; r < nrules; ++r)
+      {
+       item_number *rhsp;
+       for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+         if (ISVAR (*rhsp))
+           *rhsp =  symbol_number_as_item_number (nontermmap[*rhsp
+                                                             - ntokens]);
+      }
+    accept->number = nontermmap[accept->number - ntokens];
+  }
+
+  nsyms -= nuseless_nonterminals;
+  nvars -= nuseless_nonterminals;
+
+  free (nontermmap);

 }
 
 
 }
 
 

-/*-----------------------------------------------------------------.
-| Ouput the detailed results of the reductions.  For FILE.output.  |
-`-----------------------------------------------------------------*/
+/*------------------------------------------------------------------.
+| Output the detailed results of the reductions.  For FILE.output.  |
+`------------------------------------------------------------------*/

 
 void
 reduce_output (FILE *out)
 {
 
 void
 reduce_output (FILE *out)
 {

-  int i;
-  rule r;
-  bool b;
-

   if (nuseless_nonterminals > 0)
     {
   if (nuseless_nonterminals > 0)
     {

-      fprintf (out, _("Useless nonterminals:"));
-      fprintf (out, "\n\n");
-      for (i = ntokens; i < nsyms; i++)
-       if (!BITISSET (V, i))
-         fprintf (out, "   %s\n", tags[i]);
+      int i;
+      fprintf (out, "%s\n\n", _("Nonterminals useless in grammar"));
+      for (i = 0; i < nuseless_nonterminals; ++i)
+       fprintf (out, "   %s\n", symbols[nsyms + i]->tag);
+      fputs ("\n\n", out);

     }
     }

-  b = FALSE;
-  for (i = 0; i < ntokens; i++)
-    {
-      if (!BITISSET (V, i) && !BITISSET (V1, i))
+
+  {
+    bool b = false;
+    int i;
+    for (i = 0; i < ntokens; i++)
+      if (reduce_token_unused_in_grammar (i))

        {
          if (!b)
        {
          if (!b)

-           {
-             fprintf (out, "\n\n");
-             fprintf (out, _("Terminals which are not used:"));
-             fprintf (out, "\n\n");
-             b = TRUE;
-           }
-         fprintf (out, "   %s\n", tags[i]);
+           fprintf (out, "%s\n\n", _("Terminals unused in grammar"));
+         b = true;
+         fprintf (out, "   %s\n", symbols[i]->tag);

        }
        }

-    }
+    if (b)
+      fputs ("\n\n", out);
+  }

 
   if (nuseless_productions > 0)
 
   if (nuseless_productions > 0)

-    {
-      fprintf (out, "\n\n");
-      fprintf (out, _("Useless rules:"));
-      fprintf (out, "\n\n");
-      for (i = 1; i <= nrules; i++)
-       if (!BITISSET (P, i))
-         {
-           fprintf (out, "#%-4d  ", i);
-           fprintf (out, "%s :\t", tags[rule_table[i].lhs]);
-           for (r = &ritem[rule_table[i].rhs]; *r >= 0; r++)
-             fprintf (out, " %s", tags[*r]);
-           fprintf (out, ";\n");
-         }
-    }
-  if (nuseless_nonterminals > 0 || nuseless_productions > 0 || b)
-    fprintf (out, "\n\n");
+    grammar_rules_partial_print (out, _("Rules useless in grammar"),
+                                rule_useless_in_grammar_p);

 }
 \f
 }
 \f

-static void
-dump_grammar (FILE *out)
-{
-  int i;
-  rule r;
-
-  fprintf (out, "REDUCED GRAMMAR\n\n");
-  fprintf (out,
-        "ntokens = %d, nvars = %d, nsyms = %d, nrules = %d, nitems = %d\n\n",
-        ntokens, nvars, nsyms, nrules, nitems);
-  fprintf (out, _("Variables\n---------\n\n"));
-  fprintf (out, _("Value  Sprec    Sassoc    Tag\n"));
-  for (i = ntokens; i < nsyms; i++)
-    fprintf (out, "%5d  %5d  %5d  %s\n", i, sprec[i], sassoc[i], tags[i]);
-  fprintf (out, "\n\n");
-  fprintf (out, _("Rules\n-----\n\n"));
-  for (i = 1; i <= nrules; i++)
-    {
-      fprintf (out, "%-5d(%5d%5d)%5d : (@%-5d)",
-              i,
-              rule_table[i].prec,
-              rule_table[i].assoc,
-              rule_table[i].lhs,
-              rule_table[i].rhs);
-      for (r = &ritem[rule_table[i].rhs]; *r > 0; r++)
-       fprintf (out, "%5d", *r);
-      fprintf (out, " [%d]\n", -(*r));
-    }
-  fprintf (out, "\n\n");
-  fprintf (out, _("Rules interpreted\n-----------------\n\n"));
-  for (i = 1; i <= nrules; i++)
-    {
-      fprintf (out, "%-5d  %s :", i, tags[rule_table[i].lhs]);
-      for (r = &ritem[rule_table[i].rhs]; *r > 0; r++)
-       fprintf (out, " %s", tags[*r]);
-      fputc ('\n', out);
-    }
-  fprintf (out, "\n\n");
-}
-
-

 
 /*-------------------------------.
 | Report the results to STDERR.  |
 
 /*-------------------------------.
 | Report the results to STDERR.  |


@@ -483,27 +382,24 @@ dump_grammar (FILE *out)
 static void
 reduce_print (void)
 {
 static void
 reduce_print (void)
 {

-  if (yacc_flag && nuseless_productions)
-    fprintf (stderr, _("%d rules never reduced\n"), nuseless_productions);
-
-  fprintf (stderr, _("%s contains "), infile);
-

   if (nuseless_nonterminals > 0)
     {
   if (nuseless_nonterminals > 0)
     {

-      fprintf (stderr, _("%d useless nonterminal%s"),
-              nuseless_nonterminals,
-              (nuseless_nonterminals == 1 ? "" : "s"));
+      fprintf (stderr, "%s: %s: ", grammar_file, _("warning"));
+      fprintf (stderr, ngettext ("%d nonterminal useless in grammar",
+                                 "%d nonterminals useless in grammar",
+                                 nuseless_nonterminals),
+               nuseless_nonterminals);
+      fprintf (stderr, "\n");

     }
     }

-  if (nuseless_nonterminals > 0 && nuseless_productions > 0)
-    fprintf (stderr, _(" and "));
-

   if (nuseless_productions > 0)
     {
   if (nuseless_productions > 0)
     {

-      fprintf (stderr, _("%d useless rule%s"),
-              nuseless_productions, (nuseless_productions == 1 ? "" : "s"));
+      fprintf (stderr, "%s: %s: ", grammar_file, _("warning"));
+      fprintf (stderr, ngettext ("%d rule useless in grammar",
+                                 "%d rules useless in grammar",
+                                 nuseless_productions),
+               nuseless_productions);
+      fprintf (stderr, "\n");

     }
     }

-  fprintf (stderr, "\n");
-  fflush (stderr);

 }
 \f
 void
 }
 \f
 void


@@ -513,37 +409,56 @@ reduce_grammar (void)
 
   /* Allocate the global sets used to compute the reduced grammar */
 
 
   /* Allocate the global sets used to compute the reduced grammar */
 

-  N = XCALLOC (unsigned, WORDSIZE (nvars));
-  P = XCALLOC (unsigned, WORDSIZE (nrules + 1));
-  V = XCALLOC (unsigned, WORDSIZE (nsyms));
-  V1 = XCALLOC (unsigned, WORDSIZE (nsyms));
+  N = bitset_create (nvars, BITSET_FIXED);
+  P =  bitset_create (nrules, BITSET_FIXED);
+  V = bitset_create (nsyms, BITSET_FIXED);
+  V1 = bitset_create (nsyms, BITSET_FIXED);

 
   useless_nonterminals ();
   inaccessable_symbols ();
 
 
   useless_nonterminals ();
   inaccessable_symbols ();
 

-  reduced = (bool) (nuseless_nonterminals + nuseless_productions > 0);
-
+  reduced = (nuseless_nonterminals + nuseless_productions > 0);

   if (!reduced)
     return;
 
   reduce_print ();
 
   if (!reduced)
     return;
 
   reduce_print ();
 

-  if (!BITISSET (N, start_symbol - ntokens))
-    fatal (_("Start symbol %s does not derive any sentence"),
-          tags[start_symbol]);
+  if (!bitset_test (N, accept->number - ntokens))
+    fatal_at (startsymbol_location,
+             _("start symbol %s does not derive any sentence"),
+             startsymbol->tag);

 
 

-  reduce_grammar_tables ();
+  /* First reduce the nonterminals, as they renumber themselves in the
+     whole grammar.  If you change the order, nonterms would be
+     renumbered only in the reduced grammar.  */
+  if (nuseless_nonterminals > 0)
+    nonterminals_reduce ();
+  if (nuseless_productions > 0)
+    reduce_grammar_tables ();

 
 

-  if (trace_flag)
+  if (trace_flag & trace_grammar)

     {
     {

-      dump_grammar (stderr);
+      grammar_dump (stderr, "Reduced Grammar");

 
       fprintf (stderr, "reduced %s defines %d terminals, %d nonterminals\
 , and %d productions.\n",
 
       fprintf (stderr, "reduced %s defines %d terminals, %d nonterminals\
 , and %d productions.\n",

-              infile, ntokens, nvars, nrules);
+              grammar_file, ntokens, nvars, nrules);

     }
 }
 
     }
 }
 

+bool
+reduce_token_unused_in_grammar (symbol_number i)
+{
+  aver (i < ntokens);
+  return !bitset_test (V, i) && !bitset_test (V1, i);
+}
+
+bool
+reduce_nonterminal_useless_in_grammar (symbol_number i)
+{
+  aver (ntokens <= i && i < nsyms + nuseless_nonterminals);
+  return nsyms <= i;
+}

 
 /*-----------------------------------------------------------.
 | Free the global sets used to compute the reduced grammar.  |
 
 /*-----------------------------------------------------------.
 | Free the global sets used to compute the reduced grammar.  |


@@ -552,8 +467,8 @@ reduce_grammar (void)
 void
 reduce_free (void)
 {
 void
 reduce_free (void)
 {

-  XFREE (N);
-  XFREE (V);
-  XFREE (V1);
-  XFREE (P);
+  bitset_free (N);
+  bitset_free (V);
+  bitset_free (V1);
+  bitset_free (P);

 }
 }