From 9c2c67e6fee0853016620cfa0addd00c79d0b8e7 Mon Sep 17 00:00:00 2001 From: Akim Demaille Date: Sat, 15 Dec 2001 16:21:44 +0000 Subject: [PATCH] * src/nullable.c (set_nullable): Useless rules must be skipped, otherwise, since we range over their symbols, we might look at a nonterminal which no longer ``exists'', i.e., it is not counted in `nvars', hence we overflow our arrays. --- ChangeLog | 7 +++++++ src/nullable.c | 57 ++++++++++++++++++++++++++------------------------ 2 files changed, 37 insertions(+), 27 deletions(-) diff --git a/ChangeLog b/ChangeLog index ca964b73..21c7c473 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2001-12-15 Akim Demaille + + * src/nullable.c (set_nullable): Useless rules must be skipped, + otherwise, since we range over their symbols, we might look at a + nonterminal which no longer ``exists'', i.e., it is not counted in + `nvars', hence we overflow our arrays. + 2001-12-15 Akim Demaille The header can also be produced directly, without any obstack! diff --git a/src/nullable.c b/src/nullable.c index bbd8e319..000b8b1b 100644 --- a/src/nullable.c +++ b/src/nullable.c @@ -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; + } } } -- 2.47.2