* src/lalr.c (lookaheads_print): New.

[bison.git] / src / nullable.c

diff --git a/src/nullable.c b/src/nullable.c
index bbd8e3197d4dd6b11c064c00c9e40f0d7a138916..0b6d614f9b54ba0248ed438d09dfc1e5dd46d4dd 100644 (file)
--- a/src/nullable.c
+++ b/src/nullable.c
@@ -57,8 +57,8 @@ set_nullable (void)
      Hence we must allocate room for useless nonterminals too.  */
   shorts **rsets = XCALLOC (shorts *, nvars) - ntokens;
   /* This is said to be more elements than we actually use.
-     Supposedly nitems - nrules is enough.  But why take the risk?  */
-  shorts *relts = XCALLOC (shorts, nitems + nvars + 1);
+     Supposedly NRITEMS - NRULES is enough.  But why take the risk?  */
+  shorts *relts = XCALLOC (shorts, nritems + nvars + 1);
 
   if (trace_flag)
     fprintf (stderr, "Entering set_nullable\n");
@@ -69,35 +69,38 @@ set_nullable (void)
   p = relts;
 
   for (ruleno = 1; ruleno < nrules + 1; ++ruleno)
-    if (ritem[rule_table[ruleno].rhs] > 0)
+    if (rule_table[ruleno].useful)
       {
-       /* This rule has a non empty RHS. */
-       short *r;
-       int any_tokens = 0;
-       for (r = ritem + rule_table[ruleno].rhs; *r > 0; ++r)
-         if (ISTOKEN (*r))
-           any_tokens = 1;
-
-       /* This rule has only nonterminals: schedule it for the second
-          pass.  */
-       if (!any_tokens)
-         for (r = ritem + rule_table[ruleno].rhs; *r > 0; ++r)
-           {
-             rcount[ruleno]++;
-             p->next = rsets[*r];
-             p->value = ruleno;
-             rsets[*r] = p;
-             p++;
-           }
-      }
-    else
-      {
-       /* This rule has an empty RHS. */
-       assert (ritem[rule_table[ruleno].rhs] == -ruleno);
-       if (rule_table[ruleno].useful && !nullable[rule_table[ruleno].lhs])
+       if (ritem[rule_table[ruleno].rhs] >= 0)
+         {
+           /* This rule has a non empty RHS. */
+           short *r;
+           int any_tokens = 0;
+           for (r = &ritem[rule_table[ruleno].rhs]; *r >= 0; ++r)
+             if (ISTOKEN (*r))
+               any_tokens = 1;
+
+           /* This rule has only nonterminals: schedule it for the second
+              pass.  */
+           if (!any_tokens)
+             for (r = &ritem[rule_table[ruleno].rhs]; *r >= 0; ++r)
+               {
+                 rcount[ruleno]++;
+                 p->next = rsets[*r];
+                 p->value = ruleno;
+                 rsets[*r] = p;
+                 p++;
+               }
+         }
+       else
          {
-           nullable[rule_table[ruleno].lhs] = 1;
-           *s2++ = rule_table[ruleno].lhs;
+           /* This rule has an empty RHS. */
+           assert (ritem[rule_table[ruleno].rhs] == -ruleno);
+           if (rule_table[ruleno].useful && !nullable[rule_table[ruleno].lhs])
+             {
+               nullable[rule_table[ruleno].lhs] = 1;
+               *s2++ = rule_table[ruleno].lhs;
+             }
          }
       }