X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/0c2d3f4cba35c4bbea660794ab3cf91c030aafd3..d4bd22956952464408f6d1c7aa3f82fd60f9f17d:/src/reduce.c

diff --git a/src/reduce.c b/src/reduce.c
index fd6f9e15..2e309a44 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -1,22 +1,22 @@
 /* Grammar reduction for Bison.
-   Copyright (C) 1988, 1989, 2000, 2001, 2002  Free Software Foundation, Inc.
+
+   Copyright (C) 1988, 1989, 2000, 2001, 2002, 2003, 2005, 2006,
+   2007 Free Software Foundation, Inc.
 
    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
-   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
-   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,
@@ -25,17 +25,20 @@
 /* Don't eliminate unreachable terminals: They may be used by the
    user's parser.  */
 
+#include <config.h>
 #include "system.h"
-#include "quotearg.h"
-#include "getargs.h"
+
+#include <bitset.h>
+#include <quotearg.h>
+
+#include "complain.h"
 #include "files.h"
-#include "symtab.h"
+#include "getargs.h"
 #include "gram.h"
-#include "complain.h"
-#include "reduce.h"
+#include "print-xml.h"
 #include "reader.h"
-#include "getargs.h"
-#include "bitset.h"
+#include "reduce.h"
+#include "symtab.h"
 
 /* Set of all nonterminals which are not useless.  */
 static bitset N;
@@ -50,10 +53,10 @@ static bitset V;
    `useless', but no warning should be issued).  */
 static bitset V1;
 
-static int nuseful_productions;
-int nuseless_productions;
+static rule_number nuseful_productions;
+rule_number nuseless_productions;
 static int nuseful_nonterminals;
-int nuseless_nonterminals;
+symbol_number nuseless_nonterminals;
 
 /*-------------------------------------------------------------------.
 | Another way to do this would be with a set for each production and |
@@ -62,18 +65,17 @@ int nuseless_nonterminals;
 `-------------------------------------------------------------------*/
 
 static bool
-useful_production (int i, bitset N0)
+useful_production (rule_number r, bitset N0)
 {
-  item_number_t *r;
-  short n;
+  item_number *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))
-      return FALSE;
-  return TRUE;
+  for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+    if (ISVAR (*rhsp) && !bitset_test (N0, *rhsp - ntokens))
+      return false;
+  return true;
 }
 
 
@@ -85,7 +87,7 @@ static void
 useless_nonterminals (void)
 {
   bitset Np, Ns;
-  int i;
+  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.  */
@@ -112,12 +114,12 @@ 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;
@@ -134,9 +136,6 @@ static void
 inaccessable_symbols (void)
 {
   bitset Vp, Vs, Pp;
-  int i;
-  short t;
-  item_number_t *r;
 
   /* Find out which productions are reachable and which symbols are
      used.  Starting with an empty set of productions and a set of
@@ -162,26 +161,28 @@ 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, accept->number - ntokens))
     {
-      bitset_set (V, start_symbol);
+      bitset_set (V, accept->number);
 
       while (1)
 	{
+	  rule_number 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 *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))
@@ -196,7 +197,7 @@ inaccessable_symbols (void)
   V = Vp;
 
   /* Tokens 0, 1, and 2 are internal to Bison.  Consider them useful. */
-  bitset_set (V, eoftoken->number);		/* end-of-input 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 */
 
@@ -207,15 +208,21 @@ 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 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 r;
+    for (r = 0; r < nrules; ++r)
+      if (rules[r].precsym != 0)
+	bitset_set (V1, rules[r].precsym->number);
+  }
 }
 
 
@@ -227,42 +234,43 @@ 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 r;
+    for (r = 0; r < nrules; r++)
+      rules[r].useful = bitset_test (P, r);
+    grammar_rules_never_reduced_report (_("useless rule"));
   }
 
   /* 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 *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 (i = 1; i < nrules + 1; ++i)
+    for (r = 0; r < nrules; ++r)
       {
-	item_number_t *rhsp = rules[i].rhs;
+	item_number *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.  */
   {
-    int r;
+    rule_number 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;
@@ -278,50 +286,55 @@ reduce_grammar_tables (void)
 static void
 nonterminals_reduce (void)
 {
-  token_number_t i, n;
+  symbol_number i, n;
 
   /* Map the nonterminals to their new index: useful first, useless
      afterwards.  Kept for later report.  */
 
-  token_number_t *nontermmap = XCALLOC (token_number_t, nvars) - ntokens;
+  symbol_number *nontermmap = xnmalloc (nvars, sizeof *nontermmap);
   n = ntokens;
   for (i = ntokens; i < nsyms; i++)
     if (bitset_test (V, i))
-      nontermmap[i] = n++;
+      nontermmap[i - ntokens] = n++;
   for (i = ntokens; i < nsyms; i++)
     if (!bitset_test (V, i))
-      nontermmap[i] = n++;
+      {
+	nontermmap[i - ntokens] = n++;
+	warn_at (symbols[i]->location, _("useless nonterminal: %s"),
+		 symbols[i]->tag);
+      }
 
 
   /* Shuffle elements of tables indexed by symbol number.  */
   {
-    symbol_t **symbols_sorted = XMALLOC (symbol_t *, nvars) - ntokens;
+    symbol **symbols_sorted = xnmalloc (nvars, sizeof *symbols_sorted);
 
     for (i = ntokens; i < nsyms; i++)
-      symbols[i]->number = nontermmap[i];
+      symbols[i]->number = nontermmap[i - ntokens];
     for (i = ntokens; i < nsyms; i++)
-      symbols_sorted[nontermmap[i]] = symbols[i];
+      symbols_sorted[nontermmap[i - ntokens] - ntokens] = symbols[i];
     for (i = ntokens; i < nsyms; i++)
-      symbols[i] = symbols_sorted[i];
-    free (symbols_sorted + ntokens);
+      symbols[i] = symbols_sorted[i - ntokens];
+    free (symbols_sorted);
   }
 
   {
-    int r;
-    for (r = 1; r < nrules + 1; ++r)
+    rule_number r;
+    for (r = 0; r < nrules; ++r)
       {
-	item_number_t *rhsp;
+	item_number *rhsp;
 	for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
 	  if (ISVAR (*rhsp))
-	    *rhsp =  token_number_as_item_number (nontermmap[*rhsp]);
+	    *rhsp =  symbol_number_as_item_number (nontermmap[*rhsp
+							      - ntokens]);
       }
-    start_symbol = nontermmap[start_symbol];
+    accept->number = nontermmap[accept->number - ntokens];
   }
 
   nsyms -= nuseless_nonterminals;
   nvars -= nuseless_nonterminals;
 
-  free (nontermmap + ntokens);
+  free (nontermmap);
 }
 
 
@@ -335,51 +348,89 @@ reduce_output (FILE *out)
   if (nuseless_nonterminals > 0)
     {
       int i;
-      fprintf (out, "%s\n\n", _("Useless nonterminals:"));
+      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);
     }
 
   {
-    bool b = FALSE;
+    bool b = false;
     int i;
     for (i = 0; i < ntokens; i++)
       if (!bitset_test (V, i) && !bitset_test (V1, i))
 	{
 	  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\n", _("Terminals which are not used"));
+	  b = true;
+	  fprintf (out, "   %s\n", symbols[i]->tag);
 	}
     if (b)
       fputs ("\n\n", out);
   }
 
   if (nuseless_productions > 0)
+    grammar_rules_partial_print (out, _("Useless rules"),
+				 rule_useless_p);
+}
+
+
+/*--------------------------------------------------------------.
+| Output the detailed results of the reductions.  For FILE.xml. |
+`---------------------------------------------------------------*/
+
+void
+reduce_xml (FILE *out, int level)
+{
+  fputc ('\n', out);
+  xml_puts (out, level, "<reductions>");
+  xml_puts (out, level + 1, "<useless>");
+
+  if (nuseless_nonterminals > 0)
     {
       int i;
-      fprintf (out, "%s\n\n", _("Useless rules:"));
-      for (i = nrules + 1; i < nuseless_productions + nrules + 1; i++)
-	{
-	  item_number_t *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);
+      xml_puts (out, level + 2, "<nonterminals>");
+      for (i = 0; i < nuseless_nonterminals; ++i)
+	xml_printf (out, level + 3,
+		    "<nonterminal>%s</nonterminal>",
+		    symbols[nsyms + i]->tag);
+      xml_puts (out, level + 2, "</nonterminals>");
     }
-}
-
+  else
+    xml_puts (out, level + 2, "<nonterminals/>");
+
+  if (nuseless_productions > 0)
+    grammar_rules_partial_print_xml (out, level + 1, true, rule_useless_p);
+  else
+    xml_puts (out, level + 2, "<rules/>");
 
+  xml_puts (out, level + 1, "</useless>");
+  xml_puts (out, level + 1, "<unused>");
 
+  {
+    bool b = false;
+    int i;
+    for (i = 0; i < ntokens; i++)
+      if (!bitset_test (V, i) && !bitset_test (V1, i))
+	{
+	  if (!b)
+	    xml_puts (out, level + 2, "<terminals>");
+	  b = true;
+	  xml_printf (out, level + 3,
+		      "<terminal>%s</terminal>",
+		      xml_escape (symbols[i]->tag));
+	}
+    if (b)
+      xml_puts (out, level + 2, "</terminals>");
+    else
+      xml_puts (out, level + 2, "<terminals/>");
+  }
 
+  xml_puts (out, level + 1, "</unused>");
+  xml_puts (out, level, "</reductions>");
+  fputc ('\n', out);
+}
+
 
 /*-------------------------------.
 | Report the results to STDERR.  |
@@ -394,7 +445,7 @@ reduce_print (void)
 			       nuseless_productions),
 	     nuseless_productions);
 
-  fprintf (stderr, _("%s contains "), infile);
+  fprintf (stderr, "%s: %s: ", grammar_file, _("warning"));
 
   if (nuseless_nonterminals > 0)
     fprintf (stderr, ngettext ("%d useless nonterminal",
@@ -411,7 +462,6 @@ reduce_print (void)
 			       nuseless_productions),
 	     nuseless_productions);
   fprintf (stderr, "\n");
-  fflush (stderr);
 }
 
 void
@@ -422,22 +472,23 @@ 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);
 
   useless_nonterminals ();
   inaccessable_symbols ();
 
-  reduced = (bool) (nuseless_nonterminals + nuseless_productions > 0);
+  reduced = (nuseless_nonterminals + nuseless_productions > 0);
   if (!reduced)
     return;
 
   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, accept->number - ntokens))
+    fatal_at (startsymbol_location,
+	      _("start symbol %s does not derive any sentence"),
+	      startsymbol->tag);
 
   /* First reduce the nonterminals, as they renumber themselves in the
      whole grammar.  If you change the order, nonterms would be
@@ -447,13 +498,13 @@ reduce_grammar (void)
   if (nuseless_productions > 0)
     reduce_grammar_tables ();
 
-  if (trace_flag)
+  if (trace_flag & trace_grammar)
     {
       grammar_dump (stderr, "Reduced Grammar");
 
       fprintf (stderr, "reduced %s defines %d terminals, %d nonterminals\
 , and %d productions.\n",
-	       infile, ntokens, nvars, nrules);
+	       grammar_file, ntokens, nvars, nrules);
     }
 }