z3-z3-4.13.0.src.model.model_macro_solver.cpp Maven / Gradle / Ivy
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/*++
Copyright (c) 2006 Microsoft Corporation
Abstract:
Macro solving utilities
Author:
Leonardo de Moura (leonardo) 2010-12-17.
--*/
#include "ast/for_each_expr.h"
#include "ast/ast_pp.h"
#include "model/model_macro_solver.h"
#include "model/model_core.h"
void base_macro_solver::set_else_interp(func_decl* f, expr* f_else) {
SASSERT(f_else != nullptr);
func_interp* fi = m_model->get_func_interp(f);
if (fi == nullptr) {
fi = alloc(func_interp, m, f->get_arity());
m_model->register_decl(f, fi);
}
fi->set_else(f_else);
TRACE("model_finder", tout << f->get_name() << " " << mk_pp(f_else, m) << "\n";);
}
void base_macro_solver::operator()(model_core& m, ptr_vector& qs, ptr_vector& residue) {
m_model = &m;
ptr_vector curr_qs(qs), new_qs;
while (process(curr_qs, new_qs, residue)) {
curr_qs.swap(new_qs);
new_qs.reset();
}
std::swap(qs, new_qs);
}
/**
\brief Return true if \c f is in (qs\{q})
*/
bool simple_macro_solver::contains(func_decl* f, ptr_vector const& qs, quantifier* q) {
for (quantifier* other : qs) {
if (q == other)
continue;
quantifier_macro_info* other_qi = get_qinfo(other);
if (other_qi->contains_ng_decl(f))
return true;
}
return false;
}
bool simple_macro_solver::process(quantifier* q, ptr_vector const& qs) {
quantifier_macro_info* qi = get_qinfo(q);
for (cond_macro* m : qi->macros()) {
if (!m->satisfy_atom())
continue;
func_decl* f = m->get_f();
if (!contains(f, qs, q)) {
qi->set_the_one(f);
expr* f_else = m->get_def();
SASSERT(f_else != nullptr);
// Remark: I can ignore the conditions of m because
// I know the (partial) interpretation of f satisfied the ground part.
// MBQI will force extra instantiations if the (partial) interpretation of f
// does not satisfy the quantifier.
// In all other cases the "else" of f will satisfy the quantifier.
set_else_interp(f, f_else);
TRACE("model_finder", tout << "satisfying the quantifier using simple macro:\n";
m->display(tout); tout << "\n";);
return true; // satisfied quantifier
}
}
return false;
}
bool simple_macro_solver::process(ptr_vector const& qs, ptr_vector& new_qs, ptr_vector& residue) {
bool removed = false;
for (quantifier* q : qs) {
if (process(q, qs))
removed = true;
else
new_qs.push_back(q);
}
return removed;
}
void hint_macro_solver::insert_q_f(quantifier* q, func_decl* f) {
SASSERT(!m_forbidden.contains(f));
quantifier_set* s = nullptr;
if (!m_q_f.find(f, s)) {
s = alloc(quantifier_set);
m_q_f.insert(f, s);
m_qsets.push_back(s);
}
SASSERT(s != nullptr);
s->insert(q);
}
void hint_macro_solver::insert_f2def(func_decl* f, expr* def) {
expr_set* s = nullptr;
if (!m_f2defs.find(f, s)) {
s = alloc(expr_set);
m_f2defs.insert(f, s);
m_esets.push_back(s);
}
SASSERT(s != nullptr);
s->insert(def);
}
void hint_macro_solver::insert_q_f_def(quantifier* q, func_decl* f, expr* def) {
SASSERT(!m_forbidden.contains(f));
quantifier_set* s = nullptr;
if (!m_q_f_def.find(f, def, s)) {
s = alloc(quantifier_set);
m_q_f_def.insert(f, def, s);
insert_f2def(f, def);
m_qsets.push_back(s);
}
SASSERT(s != nullptr);
s->insert(q);
}
hint_macro_solver::quantifier_set* hint_macro_solver::get_q_f_def(func_decl* f, expr* def) {
quantifier_set* s = nullptr;
m_q_f_def.find(f, def, s);
SASSERT(s != nullptr);
return s;
}
void hint_macro_solver::reset_q_fs() {
std::for_each(m_qsets.begin(), m_qsets.end(), delete_proc());
std::for_each(m_esets.begin(), m_esets.end(), delete_proc());
m_q_f.reset();
m_q_f_def.reset();
m_qsets.reset();
m_f2defs.reset();
m_esets.reset();
}
bool hint_macro_solver::is_candidate(quantifier* q) const {
quantifier_macro_info* qi = get_qinfo(q);
for (cond_macro* m : qi->macros()) {
if (m->satisfy_atom() && !m_forbidden.contains(m->get_f()))
return true;
}
return false;
}
void hint_macro_solver::register_decls_as_forbidden(quantifier* q) {
quantifier_macro_info* qi = get_qinfo(q);
func_decl_set const& ng_decls = qi->get_ng_decls();
for (func_decl* f : ng_decls) {
m_forbidden.insert(f);
}
}
void hint_macro_solver::preprocess(ptr_vector const& qs, ptr_vector& qcandidates, ptr_vector& non_qcandidates) {
ptr_vector curr(qs);
while (true) {
for (quantifier* q : curr) {
if (is_candidate(q)) {
qcandidates.push_back(q);
}
else {
register_decls_as_forbidden(q);
non_qcandidates.push_back(q);
}
}
if (curr.size() == qcandidates.size())
return;
SASSERT(qcandidates.size() < curr.size());
curr.swap(qcandidates);
qcandidates.reset();
}
}
void hint_macro_solver::mk_q_f_defs(ptr_vector const& qs) {
for (quantifier* q : qs) {
quantifier_macro_info* qi = get_qinfo(q);
func_decl_set const& ng_decls = qi->get_ng_decls();
for (func_decl* f : ng_decls) {
if (!m_forbidden.contains(f))
insert_q_f(q, f);
}
for (cond_macro* m : qi->macros()) {
if (m->satisfy_atom() && !m_forbidden.contains(m->get_f())) {
insert_q_f_def(q, m->get_f(), m->get_def());
m_candidates.insert(m->get_f());
}
}
}
}
void hint_macro_solver::display_quantifier_set(std::ostream& out, quantifier_set const* s) {
for (quantifier* q : *s) {
out << q->get_qid() << " ";
}
out << "\n";
}
void hint_macro_solver::display_qcandidates(std::ostream& out, ptr_vector const& qcandidates) const {
for (quantifier* q : qcandidates) {
out << q->get_qid() << " ->\n" << mk_pp(q, m) << "\n";
quantifier_macro_info* qi = get_qinfo(q);
qi->display(out);
out << "------\n";
}
out << "Sets Q_f\n";
for (auto const& kv : m_q_f) {
func_decl* f = kv.m_key;
quantifier_set* s = kv.m_value;
out << f->get_name() << " -> "; display_quantifier_set(out, s);
}
out << "Sets Q_{f = def}\n";
for (auto const& kv : m_q_f_def) {
func_decl* f = kv.get_key1();
expr* def = kv.get_key2();
quantifier_set* s = kv.get_value();
out << f->get_name() << " " << mk_pp(def, m) << " ->\n"; display_quantifier_set(out, s);
}
}
void hint_macro_solver::display_search_state(std::ostream& out) const {
out << "fs:\n";
for (auto const& kv : m_fs) {
out << kv.m_key->get_name() << " ";
}
out << "\nsatisfied:\n";
for (auto q : m_satisfied) {
out << q->get_qid() << " ";
}
out << "\nresidue:\n";
for (auto q : m_residue) {
out << q->get_qid() << " ";
}
out << "\n";
}
bool hint_macro_solver::check_satisfied_residue_invariant() {
DEBUG_CODE(
for (quantifier* q : m_satisfied) {
SASSERT(!m_residue.contains(q));
auto* qi = get_qinfo(q);
SASSERT(qi != nullptr);
SASSERT(qi->get_the_one() != nullptr);
});
return true;
}
bool hint_macro_solver::update_satisfied_residue(func_decl* f, expr* def) {
bool useful = false;
SASSERT(check_satisfied_residue_invariant());
quantifier_set* q_f = get_q_f(f);
quantifier_set* q_f_def = get_q_f_def(f, def);
for (quantifier* q : *q_f_def) {
if (!m_satisfied.contains(q)) {
useful = true;
m_residue.erase(q);
m_satisfied.insert(q);
quantifier_macro_info* qi = get_qinfo(q);
SASSERT(qi->get_the_one() == 0);
qi->set_the_one(f); // remark... event handler will reset it during backtracking.
}
}
if (!useful)
return false;
for (quantifier* q : *q_f) {
if (!m_satisfied.contains(q)) {
m_residue.insert(q);
}
}
SASSERT(check_satisfied_residue_invariant());
return true;
}
/**
\brief Extract from m_residue, func_decls that can be used as macros to satisfy it.
The candidates must not be elements of m_fs.
*/
void hint_macro_solver::get_candidates_from_residue(func_decl_set& candidates) {
for (quantifier* q : m_residue) {
quantifier_macro_info* qi = get_qinfo(q);
for (cond_macro* m : qi->macros()) {
func_decl* f = m->get_f();
if (m->satisfy_atom() && !m_forbidden.contains(f) && !m_fs.contains(f)) {
candidates.insert(f);
}
}
}
}
#define GREEDY_MAX_DEPTH 10 /* to avoid too expensive search spaces */
/**
\brief Try to reduce m_residue using the macros of f.
*/
void hint_macro_solver::greedy(func_decl* f, unsigned depth) {
if (depth >= GREEDY_MAX_DEPTH)
return; // failed
TRACE("model_finder_hint",
tout << "greedy depth: " << depth << ", f: " << f->get_name() << "\n";
display_search_state(tout););
expr_set* s = get_f_defs(f);
for (expr* def : *s) {
SASSERT(!m_fs.contains(f));
m_satisfied.push_scope();
m_residue.push_scope();
TRACE("model_finder", tout << f->get_name() << " " << mk_pp(def, m) << "\n";);
m_fs.insert(f, def);
if (update_satisfied_residue(f, def)) {
// update was useful
greedy(depth + 1); // greedy throws exception in case of success
// reachable iff greedy failed.
}
m_satisfied.pop_scope();
m_residue.pop_scope();
m_fs.erase(f);
}
}
/**
\brief check if satisfied subset introduces a cyclic dependency.
f_1 = def_1(f_2), ..., f_n = def_n(f_1)
*/
bool hint_macro_solver::is_cyclic() {
m_acyclic.reset();
while (true) {
unsigned sz = m_acyclic.size();
if (sz == m_fs.size()) return false; // there are no cyclic dependencies
for (auto const& kv : m_fs) {
func_decl* f = kv.m_key;
if (m_acyclic.contains(f)) continue;
if (is_acyclic(kv.m_value))
m_acyclic.insert(f);
}
if (sz == m_acyclic.size()) return true; // no progress, so dependency cycle found.
}
}
bool hint_macro_solver::is_acyclic(expr* def) {
m_visited.reset();
occurs_check oc(*this);
try {
for_each_expr(oc, m_visited, def);
}
catch (const occurs&) {
return false;
}
return true;
}
/**
\brief Try to reduce m_residue (if not empty) by selecting a function f
that is a macro in the residue.
*/
void hint_macro_solver::greedy(unsigned depth) {
if (m_residue.empty()) {
if (is_cyclic()) return;
TRACE("model_finder_hint",
tout << "found subset that is satisfied by macros\n";
display_search_state(tout););
throw found_satisfied_subset();
}
func_decl_set candidates;
get_candidates_from_residue(candidates);
TRACE("model_finder_hint", tout << "candidates from residue:\n";
for (func_decl* f : candidates) {
tout << f->get_name() << " ";
}
tout << "\n";);
for (func_decl* f : candidates) {
greedy(f, depth);
}
}
/**
\brief Try to find a set of quantifiers by starting to use the macros of f.
This is the "find" procedure in the comments above.
The set of satisfied quantifiers is in m_satisfied, and the remaining to be
satisfied in m_residue. When the residue becomes empty we throw the exception found_satisfied_subset.
*/
void hint_macro_solver::process(func_decl* f) {
SASSERT(m_satisfied.empty());
SASSERT(m_residue.empty());
greedy(f, 0);
}
/**
\brief Copy the quantifiers from qcandidates to new_qs that are not in m_satisfied.
*/
void hint_macro_solver::copy_non_satisfied(ptr_vector const& qcandidates, ptr_vector& new_qs) {
for (quantifier* q : qcandidates) {
if (!m_satisfied.contains(q))
new_qs.push_back(q);
}
}
/**
\brief Use m_fs to set the interpretation of the function symbols that were used to satisfy the
quantifiers in m_satisfied.
*/
void hint_macro_solver::set_interp() {
for (auto const& kv : m_fs) {
func_decl* f = kv.m_key;
expr* def = kv.m_value;
set_else_interp(f, def);
}
}
void hint_macro_solver::reset() {
reset_q_fs();
m_forbidden.reset();
m_candidates.reset();
m_satisfied.reset();
m_residue.reset();
m_fs.reset();
}
bool hint_macro_solver::process(ptr_vector const& qs, ptr_vector& new_qs, ptr_vector& residue) {
reset();
ptr_vector qcandidates;
preprocess(qs, qcandidates, new_qs);
if (qcandidates.empty()) {
SASSERT(new_qs.size() == qs.size());
return false;
}
mk_q_f_defs(qcandidates);
TRACE("model_finder_hint", tout << "starting hint-solver search using:\n"; display_qcandidates(tout, qcandidates););
for (func_decl* f : m_candidates) {
try {
process(f);
}
catch (const found_satisfied_subset&) {
set_interp();
copy_non_satisfied(qcandidates, new_qs);
return true;
}
}
// failed... copy everything to new_qs
new_qs.append(qcandidates);
return false;
}
/**
\brief Satisfy clauses that are not in the AUF fragment but define conditional macros.
These clauses are eliminated even if the symbol being defined occurs in other quantifiers.
The auf_solver is ineffective in these clauses.
\remark Full macros are used even if they are in the AUF fragment.
*/
bool non_auf_macro_solver::add_macro(func_decl* f, expr* f_else) {
TRACE("model_finder", tout << "trying to add macro for " << f->get_name() << "\n" << mk_pp(f_else, m) << "\n";);
func_decl_set* s = m_dependencies.mk_func_decl_set();
m_dependencies.collect_ng_func_decls(f_else, s);
if (!m_dependencies.insert(f, s)) {
TRACE("model_finder", tout << "failed to add macro\n";);
return false; // cyclic dependency
}
set_else_interp(f, f_else);
return true;
}
// Return true if r1 is a better macro than r2.
bool non_auf_macro_solver::is_better_macro(cond_macro* r1, cond_macro* r2) {
if (r2 == nullptr || !r1->is_hint())
return true;
if (!r2->is_hint())
return false;
SASSERT(r1->is_hint() && r2->is_hint());
if (is_ground(r1->get_def()) && !is_ground(r2->get_def()))
return true;
return false;
}
cond_macro* non_auf_macro_solver::get_macro_for(func_decl* f, quantifier* q) {
cond_macro* r = nullptr;
quantifier_macro_info* qi = get_qinfo(q);
for (cond_macro* m : qi->macros()) {
if (m->get_f() == f && !m->is_hint() && is_better_macro(m, r))
r = m;
}
return r;
}
typedef std::pair mq_pair;
void non_auf_macro_solver::collect_candidates(ptr_vector const& qs, obj_map& full_macros, func_decl_set& cond_macros) {
for (quantifier* q : qs) {
quantifier_macro_info* qi = get_qinfo(q);
for (cond_macro* m : qi->macros()) {
if (!m->is_hint()) {
func_decl* f = m->get_f();
TRACE("model_finder", tout << "considering macro for: " << f->get_name() << "\n";
m->display(tout); tout << "\n";);
if (m->is_unconditional() && (!qi->is_auf() || m->get_weight() >= m_mbqi_force_template)) {
full_macros.insert(f, std::make_pair(m, q));
cond_macros.erase(f);
}
else if (!full_macros.contains(f) && !qi->is_auf())
cond_macros.insert(f);
}
}
}
}
void non_auf_macro_solver::process_full_macros(obj_map const& full_macros, obj_hashtable& removed) {
for (auto const& kv : full_macros) {
func_decl* f = kv.m_key;
cond_macro* m = kv.m_value.first;
quantifier* q = kv.m_value.second;
SASSERT(m->is_unconditional());
if (add_macro(f, m->get_def())) {
get_qinfo(q)->set_the_one(f);
removed.insert(q);
}
}
}
void non_auf_macro_solver::process(func_decl* f, ptr_vector const& qs, obj_hashtable& removed) {
expr_ref fi_else(m);
ptr_buffer to_remove;
for (quantifier* q : qs) {
if (removed.contains(q))
continue;
cond_macro* cm = get_macro_for(f, q);
if (!cm)
continue;
SASSERT(!cm->is_hint());
if (cm->is_unconditional())
return; // f is part of a full macro... ignoring it.
to_remove.push_back(q);
if (fi_else.get() == nullptr) {
fi_else = cm->get_def();
}
else {
fi_else = m.mk_ite(cm->get_cond(), cm->get_def(), fi_else);
}
}
if (fi_else.get() != nullptr && add_macro(f, fi_else)) {
for (quantifier* q : to_remove) {
get_qinfo(q)->set_the_one(f);
removed.insert(q);
}
}
}
void non_auf_macro_solver::process_cond_macros(func_decl_set const& cond_macros, ptr_vector const& qs, obj_hashtable& removed) {
for (func_decl* f : cond_macros) {
process(f, qs, removed);
}
}
bool non_auf_macro_solver::process(ptr_vector const& qs, ptr_vector& new_qs, ptr_vector& residue) {
obj_map full_macros;
func_decl_set cond_macros;
obj_hashtable removed;
// Possible improvement: sort full_macros & cond_macros using an user provided precedence function.
collect_candidates(qs, full_macros, cond_macros);
process_full_macros(full_macros, removed);
process_cond_macros(cond_macros, qs, removed);
for (quantifier* q : qs) {
if (removed.contains(q))
continue;
new_qs.push_back(q);
residue.push_back(q);
}
return !removed.empty();
}