33-useless-prods.patch

[Akim Demaille]

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * src/reduce.c (reduce_grammar_tables): No longer disable the
        removal of useless rules via CPP but via `if (0)', so that the
        compiler still check the code is valid.
        For instance, it should have noticed `rline' no longer exists: use
        the `line' member of rule_t.
        * src/gram.c (dummy, rline): Remove, unused.
        
        
Index: src/gram.c
--- src/gram.c Sat, 01 Dec 2001 14:49:05 +0100 akim
+++ src/gram.c Tue, 04 Dec 2001 13:55:31 +0100 akim
@@ -1,30 +1,28 @@
 /* Allocate input grammar variables for bison,
    Copyright 1984, 1986, 1989, 2001 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
-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.
-
-Bison 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.  */
+   Bison 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.
+
+   Bison 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.  */
 
 
 #include "system.h"
 #include "gram.h"
 #include "reader.h"
 
-void dummy PARAMS((void));
-
 /* comments for these variables are in gram.h  */
 
 int nitems;
@@ -41,7 +39,6 @@
 short *rassoc = NULL;
 short *sassoc = NULL;
 short *token_translations = NULL;
-short *rline = NULL;
 
 int start_symbol;
 
Index: src/reduce.c
--- src/reduce.c Sat, 01 Dec 2001 13:09:59 +0100 akim
+++ src/reduce.c Tue, 04 Dec 2001 13:59:02 +0100 akim
@@ -264,28 +264,35 @@
 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++)
-       {
+  /* This is turned off because we would need to change the numbers in
+     the case statements in the actions file.
+
+     We don't disable it via CPP so that it is still checked with the
+     rest of the code, to avoid its becoming completely obsolete.
+
+     FIXME: I think the comment above demonstrates this code must be
+     turned off for *semantic* parser, not in the general case.  Try
+     to understand this better --akim.  */
+
+  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].lhs   = rule_table[pn].lhs;
+                 rule_table[np].line  = rule_table[pn].line;
+                 rule_table[np].prec  = rule_table[pn].prec;
                  rule_table[np].assoc = rule_table[pn].assoc;
-                 rule_table[np].rhs = rule_table[pn].rhs;
+                 rule_table[np].rhs   = rule_table[pn].rhs;
                  if (rule_table[np].rhs != ni)
                    {
                      pi = rule_table[np].rhs;
@@ -300,16 +307,15 @@
                  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.  */
+       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. */
   if (nuseless_productions > 0)
     {