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mirror of https://github.com/Z3Prover/z3 synced 2025-04-29 20:05:51 +00:00
This commit is contained in:
Nikolaj Bjorner 2021-02-14 13:52:10 -08:00
parent 04a1d4245c
commit 083d09aa81
14 changed files with 366 additions and 294 deletions

View file

@ -66,6 +66,7 @@ namespace recfun {
*/
void solver::assert_macro_axiom(case_expansion & e) {
m_stats.m_macro_expansions++;
TRACEFN("case expansion " << e);
SASSERT(e.m_def->is_fun_macro());
auto & vars = e.m_def->get_vars();
auto lhs = e.m_lhs;
@ -84,6 +85,14 @@ namespace recfun {
* also body-expand paths that do not depend on any defined fun
*/
void solver::assert_case_axioms(case_expansion & e) {
if (e.m_def->is_fun_macro()) {
assert_macro_axiom(e);
return;
}
++m_stats.m_case_expansions;
TRACEFN("assert_case_axioms " << e
<< " with " << e.m_def->get_cases().size() << " cases");
SASSERT(e.m_def->is_fun_defined());
// add case-axioms for all case-paths
// assert this was not defined before.
@ -106,36 +115,41 @@ namespace recfun {
disable_guard(pred_applied, guards);
continue;
}
activate_guard(pred_applied, guards);
assert_guard(pred_applied, guards);
}
add_clause(preds);
}
void solver::activate_guard(expr* pred_applied, expr_ref_vector const& guards) {
void solver::assert_guard(expr* pred_applied, expr_ref_vector const& guards) {
sat::literal_vector lguards;
for (expr* ga : guards)
lguards.push_back(mk_literal(ga));
add_equiv_and(mk_literal(pred_applied), lguards);
}
void solver::block_core(expr_ref_vector const& core) {
sat::literal_vector clause;
for (expr* e : core)
clause.push_back(~mk_literal(e));
add_clause(clause);
}
/**
* make clause `depth_limit => ~guard`
* the guard appears at a depth below the current cutoff.
*/
void solver::disable_guard(expr* guard, expr_ref_vector const& guards) {
expr_ref nguard(m.mk_not(guard), m);
if (is_disabled_guard(nguard))
return;
SASSERT(!is_enabled_guard(nguard));
sat::literal_vector c;
SASSERT(!is_enabled_guard(guard));
app_ref dlimit = m_util.mk_num_rounds_pred(m_num_rounds);
c.push_back(~mk_literal(dlimit));
c.push_back(~mk_literal(guard));
m_disabled_guards.push_back(nguard);
SASSERT(!m_guard2pending.contains(nguard));
m_guard2pending.insert(nguard, alloc(expr_ref_vector, guards));
TRACEFN("add clause\n" << c);
m_propagation_queue.push_back(alloc(propagation_item, c));
expr_ref_vector core(m);
core.push_back(dlimit);
core.push_back(guard);
if (!m_guard2pending.contains(guard)) {
m_disabled_guards.push_back(guard);
m_guard2pending.insert(guard, alloc(expr_ref_vector, guards));
}
TRACEFN("add clause\n" << core);
push_core(core);
}
/**
@ -147,6 +161,7 @@ namespace recfun {
*
*/
void solver::assert_body_axiom(body_expansion & e) {
++m_stats.m_body_expansions;
recfun::def & d = *e.m_cdef->get_def();
auto & vars = d.get_vars();
auto & args = e.m_args;
@ -184,11 +199,6 @@ namespace recfun {
return out << "disabled guards:\n" << m_disabled_guards << "\n";
}
std::ostream& solver::display_constraint(std::ostream& out, sat::ext_constraint_idx idx) const {
UNREACHABLE();
return out;
}
void solver::collect_statistics(statistics& st) const {
st.update("recfun macro expansion", m_stats.m_macro_expansions);
st.update("recfun case expansion", m_stats.m_case_expansions);
@ -196,53 +206,35 @@ namespace recfun {
}
euf::th_solver* solver::clone(euf::solver& ctx) {
return nullptr;
return alloc(solver, ctx);
}
bool solver::unit_propagate() {
force_push();
if (m_qhead == m_propagation_queue.size())
return false;
ctx.push(value_trail<unsigned>(m_qhead));
for (; m_qhead < m_propagation_queue.size() && !s().inconsistent(); ++m_qhead) {
auto& p = *m_propagation_queue[m_qhead];
if (p.is_guard()) {
expr* ng = nullptr;
VERIFY(m.is_not(p.m_guard, ng));
activate_guard(ng, *m_guard2pending[p.m_guard]);
}
else if (p.is_clause()) {
add_clause(p.m_clause);
}
else if (p.is_case()) {
recfun::case_expansion& e = *p.m_case;
if (e.m_def->is_fun_macro())
assert_macro_axiom(e);
else
assert_case_axioms(e);
++m_stats.m_case_expansions;
}
else {
SASSERT(p.is_body());
assert_body_axiom(*p.m_body);
++m_stats.m_body_expansions;
}
if (p.is_guard())
assert_guard(p.guard(), *m_guard2pending[p.guard()]);
else if (p.is_core())
block_core(p.core());
else if (p.is_case())
assert_case_axioms(p.case_ex());
else
assert_body_axiom(p.body());
}
return true;
}
void solver::push_body_expand(expr* e) {
auto* b = alloc(body_expansion, u(), to_app(e));
m_propagation_queue.push_back(alloc(propagation_item, b));
ctx.push(push_back_vector<scoped_ptr_vector<propagation_item>>(m_propagation_queue));
}
void solver::push_case_expand(expr* e) {
auto* c = alloc(case_expansion, u(), to_app(e));
m_propagation_queue.push_back(alloc(propagation_item, c));
void solver::push(propagation_item* p) {
m_propagation_queue.push_back(p);
ctx.push(push_back_vector<scoped_ptr_vector<propagation_item>>(m_propagation_queue));
}
sat::literal solver::internalize(expr* e, bool sign, bool root, bool redundant) {
force_push();
SASSERT(m.is_bool(e));
if (!visit_rec(m, e, sign, root, redundant)) {
TRACE("array", tout << mk_pp(e, m) << "\n";);
@ -255,6 +247,7 @@ namespace recfun {
}
void solver::internalize(expr* e, bool redundant) {
force_push();
visit_rec(m, e, false, false, redundant);
}
@ -268,8 +261,6 @@ namespace recfun {
return true;
if (!is_app(e) || to_app(e)->get_family_id() != get_id()) {
ctx.internalize(e, m_is_redundant);
euf::enode* n = expr2enode(e);
// TODO ensure_var(n);
return true;
}
m_stack.push_back(sat::eframe(e));
@ -284,35 +275,57 @@ namespace recfun {
n = mk_enode(e, false);
SASSERT(!n->is_attached_to(get_id()));
mk_var(n);
#if 0
for (auto* arg : euf::enode_args(n))
ensure_var(arg);
switch (a->get_decl_kind()) {
default:
UNREACHABLE();
break;
}
#endif
if (u().is_defined(e) && u().has_defs())
push_case_expand(e);
return true;
}
euf::theory_var solver::mk_var(euf::enode* n) {
return euf::null_theory_var;
}
void solver::init_search() {
void solver::add_assumptions() {
if (u().has_defs() || m_disabled_guards.empty()) {
app_ref dlimit = m_util.mk_num_rounds_pred(m_num_rounds);
TRACEFN("add_theory_assumption " << dlimit);
s().assign_scoped(mk_literal(dlimit));
for (auto g : m_disabled_guards)
s().assign_scoped(~mk_literal(g));
}
}
void solver::finalize_model(model& mdl) {
bool solver::should_research(sat::literal_vector const& core) {
bool found = false;
unsigned min_gen = UINT_MAX;
expr* to_delete = nullptr;
unsigned n = 0;
for (sat::literal lit : core) {
expr* e = ctx.bool_var2expr(lit.var());
if (lit.sign() && is_disabled_guard(e)) {
found = true;
unsigned gen = ctx.get_max_generation(e);
if (gen < min_gen)
n = 0;
if (gen <= min_gen && s().rand()() % (++n) == 0) {
to_delete = e;
min_gen = gen;
}
}
else if (u().is_num_rounds(e))
found = true;
}
if (found) {
++m_num_rounds;
if (to_delete) {
m_disabled_guards.erase(to_delete);
m_enabled_guards.push_back(to_delete);
push_guard(to_delete);
IF_VERBOSE(2, verbose_stream() << "(smt.recfun :enable-guard " << mk_pp(to_delete, m) << ")\n");
}
else {
IF_VERBOSE(2, verbose_stream() << "(smt.recfun :increment-round)\n");
}
for (expr* g : m_enabled_guards)
push_guard(g);
}
return found;
}
}