X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f16b08196c780556cbf50691e2944960aebc46f6..5cd907c478039edef5a24777056ca679a2ba624c:/src/nullable.c diff --git a/src/nullable.c b/src/nullable.c index 7ee66120..b3769fe4 100644 --- a/src/nullable.c +++ b/src/nullable.c @@ -1,7 +1,7 @@ /* Calculate which nonterminals can expand into the null string for Bison. - Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004, 2005, 2006 - Free Software Foundation, Inc. + Copyright (C) 1984, 1989, 2000-2006, 2009-2012 Free Software + Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -47,8 +47,8 @@ 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 - ntokens] ? "yes" : "no"); + fprintf (out, " %s: %s\n", symbols[i]->tag, + nullable[i - ntokens] ? "yes" : "no"); fputs ("\n\n", out); } @@ -77,52 +77,52 @@ nullable_compute (void) for (ruleno = 0; ruleno < nrules; ++ruleno) if (rules[ruleno].useful) { - 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; - } - } + 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) 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 - ntokens]) - { - nullable[r->lhs->number - ntokens] = true; - *s2++ = r->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; + } } free (squeue);