-/* 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.
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);
}
symbol_number *s2;
rule_list *p;
- symbol_number *squeue = XCALLOC (symbol_number, 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 **rsets = XCALLOC (rule_list *, 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 *relts = XCALLOC (rule_list, nritems + nvars + 1);
+ rule_list *relts = CALLOC (relts, nritems + nvars + 1);
- nullable = XCALLOC (bool, nvars) - ntokens;
+ CALLOC (nullable, nvars);
s1 = s2 = squeue;
p = relts;
if (rules_ruleno->rhs[0] >= 0)
{
/* This rule has a non empty RHS. */
- item_number *r = NULL;
+ item_number *rp = NULL;
int any_tokens = 0;
- for (r = rules_ruleno->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 = rules_ruleno->rhs; *r >= 0; ++r)
+ for (rp = rules_ruleno->rhs; *rp >= 0; ++rp)
{
rcount[ruleno]++;
- p->next = rsets[*r];
+ p->next = rsets[*rp - ntokens];
p->value = rules_ruleno;
- rsets[*r] = p;
+ rsets[*rp - ntokens] = p;
p++;
}
}
/* This rule has an empty RHS. */
if (item_number_as_rule_number (rules_ruleno->rhs[0]) != ruleno)
abort ();
- if (rules_ruleno->useful && !nullable[rules_ruleno->lhs->number])
+ if (rules_ruleno->useful
+ && ! nullable[rules_ruleno->lhs->number - ntokens])
{
- nullable[rules_ruleno->lhs->number] = 1;
+ 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 *r = p->value;
if (--rcount[r->number] == 0)
- if (r->useful && !nullable[r->lhs->number])
+ if (r->useful && ! nullable[r->lhs->number - ntokens])
{
- nullable[r->lhs->number] = 1;
+ 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)
void
nullable_free (void)
{
- XFREE (nullable + ntokens);
+ XFREE (nullable);
}