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bug-fixes to sequence theory

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-01-19 13:57:47 +01:00
parent c9373ebc9f
commit cccd502a4d
4 changed files with 87 additions and 41 deletions
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5
src/ast/rewriter/seq_rewriter.cpp
View file

@ -374,7 +374,7 @@ br_status seq_rewriter::mk_seq_length(expr* a, expr_ref& result) {
es.push_back(m_autil.mk_numeral(rational(len, rational::ui64()), true));
}
result = m_autil.mk_add(es.size(), es.c_ptr());
return BR_DONE;
return BR_REWRITE2;
}
return BR_FAILED;
}
@ -1170,14 +1170,13 @@ bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_
rs.pop_back();
}
else {
expr_ref s2(m_util.str.mk_string(s.extract(0, s.length()-2)), m());
expr_ref s2(m_util.str.mk_string(s.extract(0, s.length()-1)), m());
rs[rs.size()-1] = s2;
}
}
else {
break;
}
TRACE("seq", tout << "change back\n";);
change = true;
lchange = true;
}

1
src/ast/seq_decl_plugin.h
View file

@ -268,6 +268,7 @@ public:
MATCH_TERNARY(is_extract);
MATCH_BINARY(is_contains);
MATCH_BINARY(is_at);
MATCH_BINARY(is_index);
MATCH_TERNARY(is_index);
MATCH_TERNARY(is_replace);
MATCH_BINARY(is_prefix);

117
src/smt/theory_seq.cpp
View file

@ -244,9 +244,9 @@ bool theory_seq::branch_variable() {
unsigned k = (i + start) % sz;
eq const& e = m_eqs[k];
unsigned id = e.id();
TRACE("seq", tout << e.ls() << " = " << e.rs() << "\n";);
s = find_branch_start(2*id);
TRACE("seq", tout << s << " " << 2*id << ": " << e.ls() << " = " << e.rs() << "\n";);
bool found = find_branch_candidate(s, e.dep(), e.ls(), e.rs());
insert_branch_start(2*id, s);
if (found) {
@ -297,11 +297,14 @@ bool theory_seq::find_branch_candidate(unsigned& start, dependency* dep, expr_re
expr_ref v0(m);
v0 = m_util.str.mk_empty(m.get_sort(l));
if (can_be_equal(ls.size() - 1, ls.c_ptr() + 1, rs.size(), rs.c_ptr()) && l_false != assume_equality(l, v0)) {
TRACE("seq", tout << mk_pp(l, m) << " " << v0 << "\n";);
return true;
literal_vector lits;
if (can_be_equal(ls.size() - 1, ls.c_ptr() + 1, rs.size(), rs.c_ptr())) {
if (l_false != assume_equality(l, v0)) {
TRACE("seq", tout << mk_pp(l, m) << " " << v0 << "\n";);
return true;
}
lits.push_back(~mk_eq_empty(l));
}
// start = 0;
for (; start < rs.size(); ++start) {
unsigned j = start;
SASSERT(!m_util.str.is_concat(rs[j]));
@ -325,11 +328,11 @@ bool theory_seq::find_branch_candidate(unsigned& start, dependency* dep, expr_re
all_units &= m_util.str.is_unit(rs[j]);
}
if (all_units) {
literal_vector lits;
lits.push_back(~mk_eq_empty(l));
for (unsigned i = 0; i < rs.size(); ++i) {
v0 = mk_concat(i + 1, rs.c_ptr());
lits.push_back(~mk_eq(l, v0, false));
if (can_be_equal(ls.size() - 1, ls.c_ptr() + 1, rs.size() - i - 1, rs.c_ptr() + i + 1)) {
v0 = mk_concat(i + 1, rs.c_ptr());
lits.push_back(~mk_eq(l, v0, false));
}
}
set_conflict(dep, lits);
TRACE("seq", tout << mk_pp(l, m) << " " << v0 << "\n";);
@ -506,11 +509,23 @@ expr_ref theory_seq::mk_nth(expr* s, expr* idx) {
}
expr_ref theory_seq::mk_last(expr* s) {
zstring str;
if (m_util.str.is_string(s, str) && str.length() > 0) {
return expr_ref(m_util.str.mk_char(str, str.length()-1), m);
}
sort* char_sort = 0;
VERIFY(m_util.is_seq(m.get_sort(s), char_sort));
return mk_skolem(m_seq_last, s, 0, 0, char_sort);
}
expr_ref theory_seq::mk_first(expr* s) {
zstring str;
if (m_util.str.is_string(s, str) && str.length() > 0) {
return expr_ref(m_util.str.mk_string(str.extract(0, str.length()-1)), m);
}
return mk_skolem(m_seq_first, s);
}
void theory_seq::mk_decompose(expr* e, expr_ref& head, expr_ref& tail) {
expr* e1, *e2;
@ -819,7 +834,6 @@ bool theory_seq::solve_eqs(unsigned i) {
bool change = false;
for (; !ctx.inconsistent() && i < m_eqs.size(); ++i) {
eq const& e = m_eqs[i];
TRACE("seq", tout << i << "\n";);
if (solve_eq(e.ls(), e.rs(), e.dep())) {
if (i + 1 != m_eqs.size()) {
eq e1 = m_eqs[m_eqs.size()-1];
@ -1579,8 +1593,9 @@ void theory_seq::propagate() {
++m_axioms_head;
}
while (!m_replay.empty() && !ctx.inconsistent()) {
(*m_replay[m_replay.size()-1])(*this);
TRACE("seq", tout << "replay at level: " << ctx.get_scope_level() << "\n";);
apply* app = m_replay[m_replay.size() - 1];
(*app)(*this);
m_replay.pop_back();
}
if (m_new_solution) {
@ -1632,7 +1647,7 @@ void theory_seq::deque_axiom(expr* n) {
lit or s = "" or !prefix(s, x*s1)
*/
void theory_seq::tightest_prefix(expr* s, expr* x, literal lit1, literal lit2) {
expr_ref s1 = mk_skolem(m_seq_first, s);
expr_ref s1 = mk_first(s);
expr_ref c = mk_last(s);
expr_ref s1c = mk_concat(s1, m_util.str.mk_unit(c));
literal s_eq_emp = mk_eq_empty(s);
@ -1668,30 +1683,34 @@ void theory_seq::tightest_prefix(expr* s, expr* x, literal lit1, literal lit2) {
(len(s) <= len(t) -> i <= len(t)-len(s))
*/
void theory_seq::add_indexof_axiom(expr* i) {
expr* s, *t, *offset;
expr* s, *t, *offset = 0;
rational r;
VERIFY(m_util.str.is_index(i, t, s, offset));
VERIFY(m_util.str.is_index(i, t, s) ||
m_util.str.is_index(i, t, s, offset));
expr_ref minus_one(m_autil.mk_int(-1), m);
expr_ref zero(m_autil.mk_int(0), m);
expr_ref xsy(m);
// offset >= len(t) => indexof(s, t, offset) = -1
expr_ref len_t(m_util.str.mk_length(t), m);
literal offset_ge_len = mk_literal(m_autil.mk_ge(mk_sub(offset, len_t), zero));
add_axiom(offset_ge_len, mk_eq(i, minus_one, false));
if (m_autil.is_numeral(offset, r) && r.is_zero()) {
if (!offset || (m_autil.is_numeral(offset, r) && r.is_zero())) {
expr_ref x = mk_skolem(m_contains_left, t, s);
expr_ref y = mk_skolem(m_contains_right, t, s);
xsy = mk_concat(x,s,y);
xsy = mk_concat(x, s, y);
literal cnt = mk_literal(m_util.str.mk_contains(t, s));
literal eq_empty = mk_eq_empty(s);
add_axiom(cnt, mk_eq(i, minus_one, false));
add_axiom(~eq_empty, mk_eq(i, zero, false));
add_axiom(eq_empty, ~mk_eq_empty(t), mk_eq(i, minus_one, false));
add_axiom(~cnt, eq_empty, mk_eq(t, xsy, false));
tightest_prefix(s, x, ~cnt);
}
else {
// offset >= len(t) => indexof(s, t, offset) = -1
expr_ref len_t(m_util.str.mk_length(t), m);
literal offset_ge_len = mk_literal(m_autil.mk_ge(mk_sub(offset, len_t), zero));
add_axiom(offset_ge_len, mk_eq(i, minus_one, false));
expr_ref x = mk_skolem(m_indexof_left, t, s, offset);
expr_ref y = mk_skolem(m_indexof_right, t, s, offset);
expr_ref indexof0(m_util.str.mk_index(y, s, zero), m);
@ -2067,6 +2086,15 @@ literal theory_seq::mk_eq_empty(expr* _e) {
expr_ref e(_e, m);
SASSERT(m_util.is_seq(e));
expr_ref emp(m);
zstring s;
if (m_util.str.is_string(e, s)) {
if (s.length() == 0) {
return true_literal;
}
else {
return false_literal;
}
}
emp = m_util.str.mk_empty(m.get_sort(e));
return mk_equals(e, emp);
}
@ -2074,10 +2102,11 @@ literal theory_seq::mk_eq_empty(expr* _e) {
void theory_seq::add_axiom(literal l1, literal l2, literal l3, literal l4) {
context& ctx = get_context();
literal_vector lits;
if (l1 != null_literal) { ctx.mark_as_relevant(l1); lits.push_back(l1); }
if (l2 != null_literal) { ctx.mark_as_relevant(l2); lits.push_back(l2); }
if (l3 != null_literal) { ctx.mark_as_relevant(l3); lits.push_back(l3); }
if (l4 != null_literal) { ctx.mark_as_relevant(l4); lits.push_back(l4); }
if (l1 == true_literal || l2 == true_literal || l3 == true_literal || l4 == true_literal) return;
if (l1 != null_literal && l1 != false_literal) { ctx.mark_as_relevant(l1); lits.push_back(l1); }
if (l2 != null_literal && l2 != false_literal) { ctx.mark_as_relevant(l2); lits.push_back(l2); }
if (l3 != null_literal && l3 != false_literal) { ctx.mark_as_relevant(l3); lits.push_back(l3); }
if (l4 != null_literal && l4 != false_literal) { ctx.mark_as_relevant(l4); lits.push_back(l4); }
TRACE("seq", ctx.display_literals_verbose(tout << "axiom: ", lits.size(), lits.c_ptr()); tout << "\n";);
m_new_propagation = true;
++m_stats.m_add_axiom;
@ -2117,8 +2146,8 @@ void theory_seq::propagate_eq(literal lit, expr* e1, expr* e2, bool add_to_eqs)
}
TRACE("seq",
tout << mk_pp(ctx.bool_var2expr(lit.var()), m) << " => "
<< mk_pp(e1, m) << " = " << mk_pp(e2, m) << "\n";);
ctx.display_literals_verbose(tout, 1, &lit);
tout << " => " << mk_pp(e1, m) << " = " << mk_pp(e2, m) << "\n";);
justification* js =
ctx.mk_justification(
ext_theory_eq_propagation_justification(
@ -2161,7 +2190,7 @@ void theory_seq::assign_eh(bool_var v, bool is_true) {
propagate_non_empty(lit, e1);
// lit => e1 = first ++ (unit last)
expr_ref f1 = mk_skolem(m_seq_first, e1);
expr_ref f1 = mk_first(e1);
expr_ref f2 = mk_last(e1);
f = mk_concat(f1, m_util.str.mk_unit(f2));
propagate_eq(lit, e1, f, true);
@ -2271,6 +2300,7 @@ void theory_seq::push_scope_eh() {
}
void theory_seq::pop_scope_eh(unsigned num_scopes) {
context& ctx = get_context();
m_trail_stack.pop_scope(num_scopes);
theory::pop_scope_eh(num_scopes);
m_dm.pop_scope(num_scopes);
@ -2280,6 +2310,10 @@ void theory_seq::pop_scope_eh(unsigned num_scopes) {
m_nqs.pop_scope(num_scopes);
m_atoms.resize(m_atoms_lim[m_atoms_lim.size()-num_scopes]);
m_atoms_lim.shrink(m_atoms_lim.size()-num_scopes);
m_rewrite.reset();
if (ctx.get_base_level() > ctx.get_scope_level() - num_scopes) {
m_replay.reset();
}
}
void theory_seq::restart_eh() {
@ -2606,7 +2640,8 @@ bool theory_seq::add_prefix2prefix(expr* e) {
return false;
}
expr_ref emp(m_util.str.mk_empty(m.get_sort(e1)), m);
switch (assume_equality(e2, emp)) {
literal e2_is_emp = mk_eq_empty(e2);
switch (ctx.get_assignment(e2_is_emp)) {
case l_true:
return false; // done
case l_undef:
@ -2614,16 +2649,19 @@ bool theory_seq::add_prefix2prefix(expr* e) {
default:
break;
}
expr_ref head1(m), tail1(m), head2(m), tail2(m);
expr_ref head1(m), tail1(m), head2(m), tail2(m), conc(m);
mk_decompose(e1, head1, tail1);
mk_decompose(e2, head2, tail2);
conc = mk_concat(head2, tail2);
propagate_eq(~e2_is_emp, e2, conc, true);
literal lit = mk_eq(head1, head2, false);
switch (ctx.get_assignment(lit)) {
case l_true: {
literal_vector lits;
lits.push_back(~ctx.get_literal(e));
lits.push_back(~mk_eq(e2, emp, false));
lits.push_back(~e2_is_emp);
lits.push_back(lit);
propagate_lit(0, lits.size(), lits.c_ptr(), ~mk_literal(m_util.str.mk_prefix(tail1, tail2)));
return false;
@ -2650,28 +2688,32 @@ bool theory_seq::add_suffix2suffix(expr* e) {
}
expr_ref emp(m_util.str.mk_empty(m.get_sort(e1)), m);
switch (assume_equality(e2, emp)) {
literal e2_is_emp = mk_eq_empty(e2);
switch (ctx.get_assignment(e2_is_emp)) {
case l_true:
TRACE("seq", tout << mk_pp(e, m) << " " << mk_pp(e2, m) << " is empty\n";);
return false; // done
case l_undef:
ctx.force_phase(mk_eq(e2, emp, false));
TRACE("seq", tout << mk_pp(e, m) << " " << mk_pp(e2, m) << " is unassigned\n";);
ctx.force_phase(e2_is_emp);
return true; // retry
case l_false:
break;
}
expr_ref first2 = mk_skolem(m_seq_first, e2);
expr_ref first2 = mk_first(e2);
expr_ref last2 = mk_last(e2);
expr_ref first1 = mk_skolem(m_seq_first, e1);
expr_ref first1 = mk_first(e1);
expr_ref last1 = mk_last(e1);
expr_ref conc = mk_concat(first2, m_util.str.mk_unit(last2));
propagate_eq(~mk_eq(e2, emp, false), e2, conc);
propagate_eq(~e2_is_emp, e2, conc, true);
literal last_eq = mk_eq(last1, last2, false);
switch (ctx.get_assignment(last_eq)) {
case l_false:
TRACE("seq", tout << mk_pp(e, m) << " " << last1 << " = " << last2 << " is false\n";);
return false; // done
case l_undef:
TRACE("seq", tout << mk_pp(e, m) << " " << last1 << " = " << last2 << " is unassigned\n";);
ctx.force_phase(~last_eq);
return true;
case l_true:
@ -2680,9 +2722,10 @@ bool theory_seq::add_suffix2suffix(expr* e) {
literal_vector lits;
lits.push_back(~ctx.get_literal(e));
lits.push_back(~mk_eq(e2, emp, false));
lits.push_back(~e2_is_emp);
lits.push_back(last_eq);
propagate_lit(0, lits.size(), lits.c_ptr(), ~mk_literal(m_util.str.mk_suffix(first1, first2)));
TRACE("seq", tout << mk_pp(e, m) << " saturate\n";);
return false;
}

5
src/smt/theory_seq.h
View file

@ -192,6 +192,7 @@ namespace smt {
expr_ref m_e;
public:
replay_length_coherence(ast_manager& m, expr* e) : m_e(e, m) {}
virtual ~replay_length_coherence() {}
virtual void operator()(theory_seq& th) {
th.check_length_coherence(m_e);
m_e.reset();
@ -202,6 +203,7 @@ namespace smt {
expr_ref m_e;
public:
replay_axiom(ast_manager& m, expr* e) : m_e(e, m) {}
virtual ~replay_axiom() {}
virtual void operator()(theory_seq& th) {
th.enque_axiom(m_e);
m_e.reset();
@ -336,7 +338,7 @@ namespace smt {
void propagate_lit(dependency* dep, literal lit) { propagate_lit(dep, 0, 0, lit); }
void propagate_lit(dependency* dep, unsigned n, literal const* lits, literal lit);
void propagate_eq(dependency* dep, enode* n1, enode* n2);
void propagate_eq(literal lit, expr* e1, expr* e2, bool add_to_eqs = false);
void propagate_eq(literal lit, expr* e1, expr* e2, bool add_to_eqs);
void set_conflict(dependency* dep, literal_vector const& lits = literal_vector());
u_map<unsigned> m_branch_start;
@ -355,6 +357,7 @@ namespace smt {
bool is_tail(expr* a, expr*& s, unsigned& idx) const;
expr_ref mk_nth(expr* s, expr* idx);
expr_ref mk_last(expr* e);
expr_ref mk_first(expr* e);
expr_ref canonize(expr* e, dependency*& eqs);
bool canonize(expr* e, expr_ref_vector& es, dependency*& eqs);
bool canonize(expr_ref_vector const& es, expr_ref_vector& result, dependency*& eqs);