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Fixed some partial automaton soundness problems

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This commit is contained in:
CEisenhofer 2026-07-02 18:58:17 +02:00
parent 195a0486aa
commit e8884faa23
6 changed files with 539 additions and 251 deletions
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31
src/ast/rewriter/seq_split.cpp
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@ -223,7 +223,7 @@ bool seq_split::complement(sort* seq_sort, split_set const& sp, split_set& resul
split_set acc;
push(acc, oracle, r.mk_complement(sp[0].m_d), full);
push(acc, oracle, full, r.mk_complement(sp[0].m_n));
for (unsigned i = 1; i < sp.size(); ++i) {
for (unsigned i = 1; i < sp.size(); i++) {
split_set next;
push(next, oracle, r.mk_complement(sp[i].m_d), full);
push(next, oracle, full, r.mk_complement(sp[i].m_n));
@ -300,7 +300,7 @@ expr_ref seq_split::expand_fromre(expr* r, bool& ok) {
}
}
expr_ref acc = mk_empty();
for (unsigned i = 0; i <= str.length(); ++i) {
for (unsigned i = 0; i <= str.length(); i++) {
const expr_ref p(rex.mk_to_re(sq.str.mk_string(str.extract(0, i))), m);
const expr_ref q(rex.mk_to_re(sq.str.mk_string(str.extract(i, str.length() - i))), m);
acc = mk_union(acc, mk_single(p, q));
@ -338,7 +338,7 @@ expr_ref seq_split::expand_fromre(expr* r, bool& ok) {
app* ap = to_app(r);
const unsigned n = ap->get_num_args();
expr_ref acc = mk_empty();
for (unsigned i = 0; i < n; ++i) {
for (unsigned i = 0; i < n; i++) {
expr_ref left(m), right(m);
if (i == 0)
left = rex.mk_epsilon(seq_sort);
@ -381,8 +381,9 @@ expr_ref seq_split::expand_fromre(expr* r, bool& ok) {
app* ap = to_app(r);
const unsigned n = ap->get_num_args();
expr_ref acc = mk_fromre(ap->get_arg(0));
for (unsigned i = 1; i < n; ++i)
for (unsigned i = 1; i < n; i++) {
acc = mk_inter(acc, mk_fromre(ap->get_arg(i)));
}
return acc;
}
@ -390,10 +391,24 @@ expr_ref seq_split::expand_fromre(expr* r, bool& ok) {
if (rex.is_complement(r, a))
return mk_compl(mk_fromre(a));
// abbreviation
// difference: a \ b = a & ~b ; sigma(a \ b) = sigma(a) cap ~sigma(b).
if (rex.is_diff(r, a, b))
return mk_inter(mk_fromre(a), mk_compl(mk_fromre(b)));
// abbreviation
// optional: a? = eps | a ; sigma(a?) = sigma(eps | a) = eps cup sigma(a)
if (rex.is_opt(r, a)) {
const expr_ref eps(rex.mk_epsilon(seq_sort), m);
return mk_union(mk_single(eps, eps), mk_fromre(a));
}
// loop
unsigned l, h;
if (rex.is_loop(r, a, l, h)) {
// TODO
}
// bounded loop / ite / other: not handled (paper "v1: bail").
TRACE(seq, tout << "seq_split: unsupported regex " << mk_pp(r, m) << "\n";);
ok = false;
@ -624,7 +639,7 @@ void seq_split::simplify(split_set& pairs) const {
// 1. drop pairs with a bottom (empty-language) component.
unsigned w = 0;
for (unsigned i = 0; i < pairs.size(); ++i) {
for (unsigned i = 0; i < pairs.size(); i++) {
if (r.is_empty(pairs[i].m_d) || r.is_empty(pairs[i].m_n))
continue;
if (w != i)
@ -650,7 +665,7 @@ void seq_split::simplify(split_set& pairs) const {
struct row { expr* d; expr* n; unsigned idx; };
vector<row> rows;
for (unsigned i = 0; i < pairs.size(); ++i)
for (unsigned i = 0; i < pairs.size(); i++)
rows.push_back({ pairs[i].m_d.get(), pairs[i].m_n.get(), i });
auto subsumes = [&](row const& a, row const& b) {
@ -769,7 +784,7 @@ std::pair<expr_ref, expr_ref> seq_split::split_membership(expr* str, expr* regex
// Build the constant lookahead c and (if non-empty) an oracle that
// prunes splits whose postfix cannot match c.
zstring c;
for (i = 0; i < run_len; ++i) {
for (i = 0; i < run_len; i++) {
unsigned cv;
VERIFY(seq().str.is_unit(tokens.get(run_start + i), ch));
VERIFY(seq().is_const_char(ch, cv));
@ -791,7 +806,7 @@ std::pair<expr_ref, expr_ref> seq_split::split_membership(expr* str, expr* regex
// of each postfix
if (!c.empty()) {
unsigned w = 0;
for (i = 0; i < result.size(); ++i) {
for (i = 0; i < result.size(); i++) {
expr* d = result[i].m_n;
for (unsigned k = 0; d && !seq().re.is_empty(d) && k < c.length(); ++k) {
d = m_rw.mk_derivative(seq().mk_char(c[k]), d);