grammar: record used associativity and print useless ones

[bison.git] / src / nullable.c

diff --git a/src/nullable.c b/src/nullable.c
index c0b60f64d40235e653e2f9b7033030341d0d0580..a150f5f5c7828f11dde035e018bb02fd3f0dcb6c 100644 (file)
--- a/src/nullable.c
+++ b/src/nullable.c
@@ -1,41 +1,43 @@
-/* Part of the bison parser generator,
-   Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.
+/* Calculate which nonterminals can expand into the null string for Bison.
+
+   Copyright (C) 1984, 1989, 2000-2006, 2009-2013 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/>.  */

 
 
 /* Set up NULLABLE, a vector saying which nonterminals can expand into
    the null string.  NULLABLE[I - NTOKENS] is nonzero if symbol I can
    do so.  */
 
 
 
 /* Set up NULLABLE, a vector saying which nonterminals can expand into
    the null string.  NULLABLE[I - NTOKENS] is nonzero if symbol I can
    do so.  */
 

+#include <config.h>

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

+

 #include "getargs.h"
 #include "getargs.h"

-#include "symtab.h"

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

-#include "reduce.h"

 #include "nullable.h"
 #include "nullable.h"

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

 
 /* Linked list of rules.  */
 
 /* Linked list of rules.  */

-typedef struct rule_list_s
+typedef struct rule_list

 {
 {

-  struct rule_list_s *next;
-  rule_t *value;
-} rule_list_t;
+  struct rule_list *next;
+  rule *value;
+} rule_list;

 
 bool *nullable = NULL;
 
 
 bool *nullable = NULL;
 


@@ -45,28 +47,29 @@ nullable_print (FILE *out)
   int i;
   fputs ("NULLABLE\n", out);
   for (i = ntokens; i < nsyms; i++)
   int i;
   fputs ("NULLABLE\n", out);
   for (i = ntokens; i < nsyms; i++)

-    fprintf (out, "\t%s: %s\n", symbols[i]->tag, nullable[i] ? "yes" : "no");
+    fprintf (out, "  %s: %s\n", symbols[i]->tag,
+             nullable[i - ntokens] ? "yes" : "no");

   fputs ("\n\n", out);
 }
 
 void
 nullable_compute (void)
 {
   fputs ("\n\n", out);
 }
 
 void
 nullable_compute (void)
 {

-  rule_number_t ruleno;
-  symbol_number_t *s1;
-  symbol_number_t *s2;
-  rule_list_t *p;
+  rule_number ruleno;
+  symbol_number *s1;
+  symbol_number *s2;
+  rule_list *p;

 
 

-  symbol_number_t *squeue = XCALLOC (symbol_number_t, nvars);
-  short *rcount = XCALLOC (short, nrules);
+  symbol_number *squeue = xnmalloc (nvars, sizeof *squeue);
+  size_t *rcount = xcalloc (nrules, sizeof *rcount);

   /* RITEM contains all the rules, including useless productions.
      Hence we must allocate room for useless nonterminals too.  */
   /* RITEM contains all the rules, including useless productions.
      Hence we must allocate room for useless nonterminals too.  */

-  rule_list_t **rsets = XCALLOC (rule_list_t *, nvars) - ntokens;
+  rule_list **rsets = xcalloc (nvars, sizeof *rsets);

   /* This is said to be more elements than we actually use.
      Supposedly NRITEMS - NRULES is enough.  But why take the risk?  */
   /* This is said to be more elements than we actually use.
      Supposedly NRITEMS - NRULES is enough.  But why take the risk?  */

-  rule_list_t *relts = XCALLOC (rule_list_t, nritems + nvars + 1);
+  rule_list *relts = xnmalloc (nritems + nvars + 1, sizeof *relts);

 
 

-  nullable = XCALLOC (bool, nvars) - ntokens;
+  nullable = xcalloc (nvars, sizeof *nullable);

 
   s1 = s2 = squeue;
   p = relts;
 
   s1 = s2 = squeue;
   p = relts;


@@ -74,56 +77,58 @@ nullable_compute (void)
   for (ruleno = 0; ruleno < nrules; ++ruleno)
     if (rules[ruleno].useful)
       {
   for (ruleno = 0; ruleno < nrules; ++ruleno)
     if (rules[ruleno].useful)
       {

-       rule_t *rule = &rules[ruleno];
-       if (rule->rhs[0] >= 0)
-         {
-           /* This rule has a non empty RHS. */
-           item_number_t *r = NULL;
-           int any_tokens = 0;
-           for (r = rule->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 = rule->rhs; *r >= 0; ++r)
-               {
-                 rcount[ruleno]++;
-                 p->next = rsets[*r];
-                 p->value = rule;
-                 rsets[*r] = p;
-                 p++;
-               }
-         }
-       else
-         {
-           /* This rule has an empty RHS. */
-           assert (item_number_as_rule_number (rule->rhs[0]) == ruleno);
-           if (rule->useful && !nullable[rule->lhs->number])
-             {
-               nullable[rule->lhs->number] = 1;
-               *s2++ = rule->lhs->number;
-             }
-         }
+        rule *rules_ruleno = &rules[ruleno];
+        if (rules_ruleno->rhs[0] >= 0)
+          {
+            /* This rule has a non empty RHS. */
+            item_number *rp = NULL;
+            bool any_tokens = false;
+            for (rp = rules_ruleno->rhs; *rp >= 0; ++rp)
+              if (ISTOKEN (*rp))
+                any_tokens = true;
+
+            /* This rule has only nonterminals: schedule it for the second
+               pass.  */
+            if (!any_tokens)
+              for (rp = rules_ruleno->rhs; *rp >= 0; ++rp)
+                {
+                  rcount[ruleno]++;
+                  p->next = rsets[*rp - ntokens];
+                  p->value = rules_ruleno;
+                  rsets[*rp - ntokens] = p;
+                  p++;
+                }
+          }
+        else
+          {
+            /* This rule has an empty RHS. */
+            aver (item_number_as_rule_number (rules_ruleno->rhs[0])
+                  == ruleno);
+            if (rules_ruleno->useful
+                && ! nullable[rules_ruleno->lhs->number - ntokens])
+              {
+                nullable[rules_ruleno->lhs->number - ntokens] = true;
+                *s2++ = rules_ruleno->lhs->number;
+              }
+          }

       }
 
   while (s1 < s2)
       }
 
   while (s1 < s2)

-    for (p = rsets[*s1++]; p; p = p->next)
+    for (p = rsets[*s1++ - ntokens]; p; p = p->next)

       {
       {

-       rule_t *rule = p->value;
-       if (--rcount[rule->number] == 0)
-         if (rule->useful && !nullable[rule->lhs->number])
-           {
-             nullable[rule->lhs->number] = 1;
-             *s2++ = rule->lhs->number;
-           }
+        rule *r = p->value;
+        if (--rcount[r->number] == 0)
+          if (r->useful && ! nullable[r->lhs->number - ntokens])
+            {
+              nullable[r->lhs->number - ntokens] = true;
+              *s2++ = r->lhs->number;
+            }

       }
 
       }
 

-  XFREE (squeue);
-  XFREE (rcount);
-  XFREE (rsets + ntokens);
-  XFREE (relts);
+  free (squeue);
+  free (rcount);
+  free (rsets);
+  free (relts);

 
   if (trace_flag & trace_sets)
     nullable_print (stderr);
 
   if (trace_flag & trace_sets)
     nullable_print (stderr);


@@ -133,5 +138,5 @@ nullable_compute (void)
 void
 nullable_free (void)
 {
 void
 nullable_free (void)
 {

-  XFREE (nullable + ntokens);
+  free (nullable);

 }
 }