Update from Bruno Haible's 2003-04-14 patch to gnulib.

[bison.git] / src / nullable.c

diff --git a/src/nullable.c b/src/nullable.c
index c0b60f64d40235e653e2f9b7033030341d0d0580..cf6cfd68c0831b370c7693e3ddca1c1057ae1ab6 100644 (file)
--- a/src/nullable.c
+++ b/src/nullable.c
@@ -1,5 +1,7 @@
-/* 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, 2001, 2002, 2003 Free Software
+   Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -24,18 +26,19 @@
    do so.  */
 
 #include "system.h"
+
 #include "getargs.h"
-#include "symtab.h"
 #include "gram.h"
-#include "reduce.h"
 #include "nullable.h"
+#include "reduce.h"
+#include "symtab.h"
 
 /* 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;
 
@@ -45,28 +48,29 @@ nullable_print (FILE *out)
   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, "\t%s: %s\n", symbols[i]->tag,
+            nullable[i - ntokens] ? "yes" : "no");
   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 = CALLOC (squeue, nvars);
+  short *rcount = CALLOC (rcount, nrules);
   /* 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 = CALLOC (rsets, nvars);
   /* 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 = CALLOC (relts, nritems + nvars + 1);
 
-  nullable = XCALLOC (bool, nvars) - ntokens;
+  CALLOC (nullable, nvars);
 
   s1 = s2 = squeue;
   p = relts;
@@ -74,55 +78,57 @@ nullable_compute (void)
   for (ruleno = 0; ruleno < nrules; ++ruleno)
     if (rules[ruleno].useful)
       {
-       rule_t *rule = &rules[ruleno];
-       if (rule->rhs[0] >= 0)
+       rule *rules_ruleno = &rules[ruleno];
+       if (rules_ruleno->rhs[0] >= 0)
          {
            /* This rule has a non empty RHS. */
-           item_number_t *r = NULL;
+           item_number *rp = NULL;
            int any_tokens = 0;
-           for (r = rule->rhs; *r >= 0; ++r)
-             if (ISTOKEN (*r))
+           for (rp = rules_ruleno->rhs; *rp >= 0; ++rp)
+             if (ISTOKEN (*rp))
                any_tokens = 1;
 
            /* This rule has only nonterminals: schedule it for the second
               pass.  */
            if (!any_tokens)
-             for (r = rule->rhs; *r >= 0; ++r)
+             for (rp = rules_ruleno->rhs; *rp >= 0; ++rp)
                {
                  rcount[ruleno]++;
-                 p->next = rsets[*r];
-                 p->value = rule;
-                 rsets[*r] = p;
+                 p->next = rsets[*rp - ntokens];
+                 p->value = rules_ruleno;
+                 rsets[*rp - ntokens] = 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])
+           if (item_number_as_rule_number (rules_ruleno->rhs[0]) != ruleno)
+             abort ();
+           if (rules_ruleno->useful
+               && ! nullable[rules_ruleno->lhs->number - ntokens])
              {
-               nullable[rule->lhs->number] = 1;
-               *s2++ = rule->lhs->number;
+               nullable[rules_ruleno->lhs->number - ntokens] = 1;
+               *s2++ = rules_ruleno->lhs->number;
              }
          }
       }
 
   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])
+       rule *r = p->value;
+       if (--rcount[r->number] == 0)
+         if (r->useful && ! nullable[r->lhs->number - ntokens])
            {
-             nullable[rule->lhs->number] = 1;
-             *s2++ = rule->lhs->number;
+             nullable[r->lhs->number - ntokens] = 1;
+             *s2++ = r->lhs->number;
            }
       }
 
   XFREE (squeue);
   XFREE (rcount);
-  XFREE (rsets + ntokens);
+  XFREE (rsets);
   XFREE (relts);
 
   if (trace_flag & trace_sets)
@@ -133,5 +139,5 @@ nullable_compute (void)
 void
 nullable_free (void)
 {
-  XFREE (nullable + ntokens);
+  XFREE (nullable);
 }