X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/5123689ba05a181aedd892e2e2164a2288e42b22..1bfb97dba532a32dbeffddd378955055b9277303:/src/reduce.c?ds=sidebyside

diff --git a/src/reduce.c b/src/reduce.c
index 25681750..aadf3f88 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -37,9 +37,6 @@
 #include "getargs.h"
 #include "bitset.h"
 
-typedef short *rule;
-
-
 /* Set of all nonterminals which are not useless.  */
 static bitset N;
 
@@ -53,10 +50,10 @@ static bitset V;
    `useless', but no warning should be issued).  */
 static bitset V1;
 
-static int nuseful_productions;
-static int nuseless_productions;
+static rule_number_t nuseful_productions;
+rule_number_t nuseless_productions;
 static int nuseful_nonterminals;
-int nuseless_nonterminals;
+symbol_number_t nuseless_nonterminals;
 
 /*-------------------------------------------------------------------.
 | Another way to do this would be with a set for each production and |
@@ -65,16 +62,15 @@ int nuseless_nonterminals;
 `-------------------------------------------------------------------*/
 
 static bool
-useful_production (int i, bitset N0)
+useful_production (rule_number_t r, bitset N0)
 {
-  rule r;
-  short n;
+  item_number_t *rhsp;
 
   /* A production is useful if all of the nonterminals in its appear
      in the set of useful nonterminals.  */
 
-  for (r = rules[i].rhs; *r >= 0; r++)
-    if (ISVAR (n = *r) && !bitset_test (N0, n - ntokens))
+  for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+    if (ISVAR (*rhsp) && !bitset_test (N0, *rhsp - ntokens))
       return FALSE;
   return TRUE;
 }
@@ -88,7 +84,7 @@ static void
 useless_nonterminals (void)
 {
   bitset Np, Ns;
-  int i;
+  rule_number_t 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.  */
@@ -115,12 +111,12 @@ useless_nonterminals (void)
   while (1)
     {
       bitset_copy (Np, N);
-      for (i = 1; i < nrules + 1; i++)
-	if (!bitset_test (P, i)
-	    && useful_production (i, N))
+      for (r = 0; r < nrules; r++)
+	if (!bitset_test (P, r)
+	    && useful_production (r, N))
 	  {
-	    bitset_set (Np, rules[i].lhs->number - ntokens);
-	    bitset_set (P, i);
+	    bitset_set (Np, rules[r].lhs->number - ntokens);
+	    bitset_set (P, r);
 	  }
       if (bitset_equal_p (N, Np))
 	break;
@@ -137,9 +133,6 @@ static void
 inaccessable_symbols (void)
 {
   bitset Vp, Vs, Pp;
-  int i;
-  short t;
-  rule r;
 
   /* Find out which productions are reachable and which symbols are
      used.  Starting with an empty set of productions and a set of
@@ -165,26 +158,28 @@ inaccessable_symbols (void)
      user can know.  */
 
   Vp = bitset_create (nsyms, BITSET_FIXED);
-  Pp = bitset_create (nrules + 1, BITSET_FIXED);
+  Pp = bitset_create (nrules, BITSET_FIXED);
 
   /* If the start symbol isn't useful, then nothing will be useful. */
-  if (bitset_test (N, start_symbol - ntokens))
+  if (bitset_test (N, axiom->number - ntokens))
     {
-      bitset_set (V, start_symbol);
+      bitset_set (V, axiom->number);
 
       while (1)
 	{
+	  rule_number_t r;
 	  bitset_copy (Vp, V);
-	  for (i = 1; i < nrules + 1; i++)
+	  for (r = 0; r < nrules; r++)
 	    {
-	      if (!bitset_test (Pp, i)
-		  && bitset_test (P, i)
-		  && bitset_test (V, rules[i].lhs->number))
+	      if (!bitset_test (Pp, r)
+		  && bitset_test (P, r)
+		  && bitset_test (V, rules[r].lhs->number))
 		{
-		  for (r = rules[i].rhs; *r >= 0; r++)
-		    if (ISTOKEN (t = *r) || bitset_test (N, t - ntokens))
-		      bitset_set (Vp, t);
-		  bitset_set (Pp, i);
+		  item_number_t *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 (bitset_equal_p (V, Vp))
@@ -210,15 +205,21 @@ inaccessable_symbols (void)
   nuseless_productions = nrules - nuseful_productions;
 
   nuseful_nonterminals = 0;
-  for (i = ntokens; i < nsyms; i++)
-    if (bitset_test (V, i))
-      nuseful_nonterminals++;
+  {
+    symbol_number_t 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.  */
-  for (i = 1; i < nrules + 1; i++)
-    if (rules[i].precsym != 0)
-      bitset_set (V1, rules[i].precsym->number);
+  {
+    rule_number_t r;
+    for (r = 0; r < nrules; ++r)
+      if (rules[r].precsym != 0)
+	bitset_set (V1, rules[r].precsym->number);
+  }
 }
 
 
@@ -230,42 +231,50 @@ inaccessable_symbols (void)
 static void
 reduce_grammar_tables (void)
 {
-  /* Flag useless productions.  */
+  /* Report and flag useless productions.  */
   {
-    int pn;
-    for (pn = 1; pn < nrules + 1; pn++)
-      rules[pn].useful = bitset_test (P, pn);
+    rule_number_t r;
+    for (r = 0; r < nrules; r++)
+      {
+	rules[r].useful = bitset_test (P, r);
+	if (!rules[r].useful)
+	  {
+	    LOCATION_PRINT (stderr, rules[r].location);
+	    fprintf (stderr, ": %s: %s: ", _("warning"), _("useless rule"));
+	    rule_print (&rules[r], stderr);
+	  }
+      }
   }
 
   /* Map the nonterminals to their new index: useful first, useless
      afterwards.  Kept for later report.  */
   {
-    int useful = 1;
-    int useless = nrules + 1 - nuseless_productions;
-    rule_t *rules_sorted = XMALLOC (rule_t, nrules + 1) - 1;
-    int i;
-    for (i = 1; i < nrules + 1; ++i)
-      rules_sorted[rules[i].useful ? useful++ : useless++] = rules[i];
-    free (rules + 1);
+    int useful = 0;
+    int useless = nrules - nuseless_productions;
+    rule_t *rules_sorted = XMALLOC (rule_t, nrules);
+    rule_number_t 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 (i = 1; i < nrules + 1; ++i)
+    for (r = 0; r < nrules; ++r)
       {
-	short *rhsp = rules[i].rhs;
+	item_number_t *rhsp = rules[r].rhs;
 	for (/* Nothing. */; *rhsp >= 0; ++rhsp)
 	  /* Nothing. */;
-	*rhsp = -i;
-	rules[i].number = i;
+	*rhsp = rule_number_as_item_number (r);
+	rules[r].number = r;
       }
     nrules -= nuseless_productions;
   }
 
-  /* Adjust NRITEMS and NITEMS.  */
+  /* Adjust NRITEMS.  */
   {
     int r;
     int length;
-    for (r = nrules + 1; r < nrules + 1 + nuseless_productions; ++r)
+    for (r = nrules; r < nrules + nuseless_productions; ++r)
       {
 	length = rule_rhs_length (&rules[r]);
 	nritems -= length + 1;
@@ -281,19 +290,25 @@ reduce_grammar_tables (void)
 static void
 nonterminals_reduce (void)
 {
-  int i, n;
+  symbol_number_t i, n;
 
   /* Map the nonterminals to their new index: useful first, useless
      afterwards.  Kept for later report.  */
 
-  short *nontermmap = XCALLOC (short, nvars) - ntokens;
+  symbol_number_t *nontermmap = XCALLOC (symbol_number_t, nvars) - ntokens;
   n = ntokens;
   for (i = ntokens; i < nsyms; i++)
     if (bitset_test (V, i))
       nontermmap[i] = n++;
   for (i = ntokens; i < nsyms; i++)
     if (!bitset_test (V, i))
-      nontermmap[i] = n++;
+      {
+	nontermmap[i] = n++;
+	LOCATION_PRINT (stderr, symbols[i]->location);
+	fprintf (stderr, ": %s: %s: %s\n",
+		 _("warning"), _("useless nonterminal"),
+		 symbols[i]->tag);
+      }
 
 
   /* Shuffle elements of tables indexed by symbol number.  */
@@ -309,11 +324,17 @@ nonterminals_reduce (void)
     free (symbols_sorted + ntokens);
   }
 
-  for (i = 0; i < nritems; ++i)
-    if (ISVAR (ritem[i]))
-      ritem[i] = nontermmap[ritem[i]];
-
-  start_symbol = nontermmap[start_symbol];
+  {
+    rule_number_t r;
+    for (r = 0; r < nrules; ++r)
+      {
+	item_number_t *rhsp;
+	for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+	  if (ISVAR (*rhsp))
+	    *rhsp =  symbol_number_as_item_number (nontermmap[*rhsp]);
+      }
+    axiom->number = nontermmap[axiom->number];
+  }
 
   nsyms -= nuseless_nonterminals;
   nvars -= nuseless_nonterminals;
@@ -334,8 +355,7 @@ reduce_output (FILE *out)
       int i;
       fprintf (out, "%s\n\n", _("Useless nonterminals:"));
       for (i = 0; i < nuseless_nonterminals; ++i)
-	fprintf (out, "   %s\n", quotearg_style (escape_quoting_style,
-						 symbols[nsyms + i]->tag));
+	fprintf (out, "   %s\n", symbols[nsyms + i]->tag);
       fputs ("\n\n", out);
     }
 
@@ -348,84 +368,19 @@ reduce_output (FILE *out)
 	  if (!b)
 	    fprintf (out, "%s\n\n", _("Terminals which are not used:"));
 	  b = TRUE;
-	  fprintf (out, "   %s\n", quotearg_style (escape_quoting_style,
-						   symbols[i]->tag));
+	  fprintf (out, "   %s\n", symbols[i]->tag);
 	}
     if (b)
       fputs ("\n\n", out);
   }
 
   if (nuseless_productions > 0)
-    {
-      int i;
-      fprintf (out, "%s\n\n", _("Useless rules:"));
-      for (i = nrules + 1; i < nuseless_productions + nrules + 1; i++)
-	{
-	  rule r;
-	  fprintf (out, "#%-4d  ", rules[i].user_number - 1);
-	  fprintf (out, "%s:", quotearg_style (escape_quoting_style,
-					       rules[i].lhs->tag));
-	  for (r = rules[i].rhs; *r >= 0; r++)
-	    fprintf (out, " %s", quotearg_style (escape_quoting_style,
-						 symbols[*r]->tag));
-	  fputs (";\n", out);
-	}
-      fputs ("\n\n", out);
-    }
+    grammar_rules_partial_print (out, _("Useless rules"),
+				 nrules,
+				 nrules + nuseless_productions);
 }
 
-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, nritems = %d\n\n",
-	   ntokens, nvars, nsyms, nrules, nritems);
-  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,
-	     symbols[i]->prec, symbols[i]->assoc,
-	     quotearg_style (escape_quoting_style, symbols[i]->tag));
-  fprintf (out, "\n\n");
-  fprintf (out, "Rules\n-----\n\n");
-  fprintf (out, "Num (Prec, Assoc, Useful, Ritem Range) Lhs -> Rhs (Ritem range) [Num]\n");
-  for (i = 1; i < nrules + nuseless_productions + 1; i++)
-    {
-      int rhs_count = 0;
-      /* Find the last RHS index in ritems. */
-      for (r = rules[i].rhs; *r >= 0; ++r)
-	++rhs_count;
-      fprintf (out, "%3d (%2d, %2d, %2d, %2d-%2d)   %2d ->",
-	       i - 1,
-	       rules[i].prec->prec,
-	       rules[i].prec->assoc,
-	       rules[i].useful,
-	       rules[i].rhs - ritem,
-	       rules[i].rhs - ritem + rhs_count - 1,
-	       rules[i].lhs->number);
-      /* Dumped the RHS. */
-      for (r = rules[i].rhs; *r >= 0; r++)
-	fprintf (out, "%3d", *r);
-      fprintf (out, "  [%d]\n", -(*r) - 1);
-    }
-  fprintf (out, "\n\n");
-  fprintf (out, "Rules interpreted\n-----------------\n\n");
-  for (i = 1; i < nrules + nuseless_productions + 1; i++)
-    {
-      fprintf (out, "%-5d  %s :",
-	       i, quotearg_style (escape_quoting_style, rules[i].lhs->tag));
-      for (r = rules[i].rhs; *r >= 0; r++)
-	fprintf (out, " %s",
-		 quotearg_style (escape_quoting_style, symbols[*r]->tag));
-      fputc ('\n', out);
-    }
-  fprintf (out, "\n\n");
-}
+
 
 
 
@@ -442,7 +397,7 @@ reduce_print (void)
 			       nuseless_productions),
 	     nuseless_productions);
 
-  fprintf (stderr, _("%s contains "), infile);
+  fprintf (stderr, "%s: %s: ", infile, _("warning"));
 
   if (nuseless_nonterminals > 0)
     fprintf (stderr, ngettext ("%d useless nonterminal",
@@ -470,7 +425,7 @@ reduce_grammar (void)
   /* Allocate the global sets used to compute the reduced grammar */
 
   N = bitset_create (nvars, BITSET_FIXED);
-  P =  bitset_create (nrules + 1, BITSET_FIXED);
+  P =  bitset_create (nrules, BITSET_FIXED);
   V = bitset_create (nsyms, BITSET_FIXED);
   V1 = bitset_create (nsyms, BITSET_FIXED);
 
@@ -483,18 +438,22 @@ reduce_grammar (void)
 
   reduce_print ();
 
-  if (!bitset_test (N, start_symbol - ntokens))
-    fatal (_("Start symbol %s does not derive any sentence"),
-	   quotearg_style (escape_quoting_style, symbols[start_symbol]->tag));
+  if (!bitset_test (N, axiom->number - ntokens))
+    fatal_at (startsymbol_location,
+	      _("start symbol %s does not derive any sentence"),
+	      startsymbol->tag);
 
-  if (nuseless_productions > 0)
-    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)
     {
-      dump_grammar (stderr);
+      grammar_dump (stderr, "Reduced Grammar");
 
       fprintf (stderr, "reduced %s defines %d terminals, %d nonterminals\
 , and %d productions.\n",