diff --git a/src/smt/theory_str.cpp b/src/smt/theory_str.cpp index c4e6a9471..1f84b5faf 100644 --- a/src/smt/theory_str.cpp +++ b/src/smt/theory_str.cpp @@ -9811,33 +9811,85 @@ namespace smt { continue; } - if (exact_length_value.is_zero()) { - // shortcut - expr_ref lhs(ctx.mk_eq_atom(mk_strlen(str), m_autil.mk_numeral(rational::zero(), true)), m); - expr_ref rhs(ctx.mk_eq_atom(str, mk_string("")), m); - assert_implication(lhs, rhs); - } else { - // find a consistent automaton for this term - bool found = false; - regex_automaton_under_assumptions assumption; - if (regex_automaton_assumptions.contains(re) && - !regex_automaton_assumptions[re].empty()){ - for (svector::iterator it = regex_automaton_assumptions[re].begin(); - it != regex_automaton_assumptions[re].end(); ++it) { - regex_automaton_under_assumptions autA = *it; - rational assumed_upper_bound, assumed_lower_bound; - bool assumes_upper_bound = autA.get_upper_bound(assumed_upper_bound); - bool assumes_lower_bound = autA.get_lower_bound(assumed_lower_bound); - if (!assumes_upper_bound && !assumes_lower_bound) { - // automaton with no assumptions is always usable - assumption = autA; - found = true; - break; + + // find a consistent automaton for this term + bool found = false; + regex_automaton_under_assumptions assumption; + if (regex_automaton_assumptions.contains(re) && + !regex_automaton_assumptions[re].empty()){ + for (svector::iterator it = regex_automaton_assumptions[re].begin(); + it != regex_automaton_assumptions[re].end(); ++it) { + regex_automaton_under_assumptions autA = *it; + rational assumed_upper_bound, assumed_lower_bound; + bool assumes_upper_bound = autA.get_upper_bound(assumed_upper_bound); + bool assumes_lower_bound = autA.get_lower_bound(assumed_lower_bound); + if (!assumes_upper_bound && !assumes_lower_bound) { + // automaton with no assumptions is always usable + assumption = autA; + found = true; + break; + } + // check consistency of bounds assumptions + } // foreach(a in regex_automaton_assumptions) + } + if (found) { + if (exact_length_value.is_zero()) { + // check consistency of 0-length solution with automaton + eautomaton * aut = assumption.get_automaton(); + bool zero_solution = false; + unsigned initial_state = aut->init(); + if (aut->is_final_state(initial_state)) { + zero_solution = true; + } else { + unsigned_vector eps_states; + aut->get_epsilon_closure(initial_state, eps_states); + for (unsigned_vector::iterator it = eps_states.begin(); it != eps_states.end(); ++it) { + unsigned state = *it; + if (aut->is_final_state(state)) { + zero_solution = true; + break; + } } - // check consistency of bounds assumptions - } // foreach(a in regex_automaton_assumptions) - } - if (found) { + } + + // now check polarity of automaton wrt. original term + if ( (current_assignment == l_true && !assumption.get_polarity()) + || (current_assignment == l_false && assumption.get_polarity())) { + // invert sense + NOT_IMPLEMENTED_YET(); + } + + if (zero_solution) { + TRACE("str", tout << "zero-length solution OK -- asserting empty path constraint" << std::endl;); + expr_ref_vector lhs_terms(m); + if (current_assignment == l_true) { + lhs_terms.push_back(str_in_re); + } else { + lhs_terms.push_back(m.mk_not(str_in_re)); + } + lhs_terms.push_back(ctx.mk_eq_atom(mk_strlen(str), m_autil.mk_numeral(exact_length_value, true))); + expr_ref lhs(mk_and(lhs_terms), m); + expr_ref rhs(ctx.mk_eq_atom(str, mk_string("")), m); + assert_implication(lhs, rhs); + regex_terms_with_path_constraints.insert(str_in_re); + m_trail_stack.push(insert_obj_trail(regex_terms_with_path_constraints, str_in_re)); + } else { + TRACE("str", tout << "zero-length solution not admitted by this automaton -- asserting conflict clause" << std::endl;); + expr_ref_vector lhs_terms(m); + if (current_assignment == l_true) { + lhs_terms.push_back(str_in_re); + } else { + lhs_terms.push_back(m.mk_not(str_in_re)); + } + lhs_terms.push_back(ctx.mk_eq_atom(mk_strlen(str), m_autil.mk_numeral(exact_length_value, true))); + expr_ref lhs(mk_and(lhs_terms), m); + expr_ref conflict(m.mk_not(lhs), m); + assert_axiom(conflict); + } + regex_axiom_add = true; + regex_inc_counter(regex_length_attempt_count, re); + continue; + } else { expr_ref pathConstraint(m); expr_ref characterConstraints(m); pathConstraint = generate_regex_path_constraints(str, assumption.get_automaton(), exact_length_value, characterConstraints); @@ -9876,30 +9928,30 @@ namespace smt { TRACE("str", tout << "length attempt count for " << mk_pp(re, m) << " is " << v << std::endl;); } - continue; - } else { - // no automata available, or else all bounds assumptions are invalid - unsigned expected_complexity = estimate_regex_complexity(re); - if (expected_complexity <= m_params.m_RegexAutomata_DifficultyThreshold || regex_get_counter(regex_fail_count, str_in_re) >= m_params.m_RegexAutomata_FailedAutomatonThreshold) { - CTRACE("str", regex_get_counter(regex_fail_count, str_in_re) >= m_params.m_RegexAutomata_FailedAutomatonThreshold, - tout << "failed automaton threshold reached for " << mk_pp(str_in_re, m) << " -- automatically constructing full automaton" << std::endl;); - eautomaton * aut = m_mk_aut(re); - aut->compress(); - regex_automata.push_back(aut); - regex_automaton_under_assumptions new_aut(re, aut, true); - if (!regex_automaton_assumptions.contains(re)) { - regex_automaton_assumptions.insert(re, svector()); - } - regex_automaton_assumptions[re].push_back(new_aut); - TRACE("str", tout << "add new automaton for " << mk_pp(re, m) << ": no assumptions" << std::endl;); - regex_axiom_add = true; - find_automaton_initial_bounds(str_in_re, aut); - } else { - regex_inc_counter(regex_fail_count, str_in_re); - } continue; } - } // !length is zero + } else { + // no automata available, or else all bounds assumptions are invalid + unsigned expected_complexity = estimate_regex_complexity(re); + if (expected_complexity <= m_params.m_RegexAutomata_DifficultyThreshold || regex_get_counter(regex_fail_count, str_in_re) >= m_params.m_RegexAutomata_FailedAutomatonThreshold) { + CTRACE("str", regex_get_counter(regex_fail_count, str_in_re) >= m_params.m_RegexAutomata_FailedAutomatonThreshold, + tout << "failed automaton threshold reached for " << mk_pp(str_in_re, m) << " -- automatically constructing full automaton" << std::endl;); + eautomaton * aut = m_mk_aut(re); + aut->compress(); + regex_automata.push_back(aut); + regex_automaton_under_assumptions new_aut(re, aut, true); + if (!regex_automaton_assumptions.contains(re)) { + regex_automaton_assumptions.insert(re, svector()); + } + regex_automaton_assumptions[re].push_back(new_aut); + TRACE("str", tout << "add new automaton for " << mk_pp(re, m) << ": no assumptions" << std::endl;); + regex_axiom_add = true; + find_automaton_initial_bounds(str_in_re, aut); + } else { + regex_inc_counter(regex_fail_count, str_in_re); + } + continue; + } } // get_len_value() expr_ref str_len(mk_strlen(str), m); rational lower_bound_value;