mirror of
https://github.com/Z3Prover/z3
synced 2025-04-10 11:17:07 +00:00
361 lines
11 KiB
C++
361 lines
11 KiB
C++
/*++
|
|
Copyright (c) 2006 Microsoft Corporation
|
|
|
|
Module Name:
|
|
|
|
func_interp.cpp
|
|
|
|
Abstract:
|
|
See func_interp.h
|
|
|
|
Author:
|
|
|
|
Leonardo de Moura (leonardo) 2010-12-30.
|
|
|
|
Revision History:
|
|
|
|
--*/
|
|
#include"func_interp.h"
|
|
#include"simplifier.h"
|
|
#include"basic_simplifier_plugin.h"
|
|
#include"var_subst.h"
|
|
#include"obj_hashtable.h"
|
|
#include"ast_pp.h"
|
|
#include"ast_smt2_pp.h"
|
|
|
|
func_entry::func_entry(ast_manager & m, unsigned arity, expr * const * args, expr * result):
|
|
m_args_are_values(true),
|
|
m_result(result) {
|
|
SASSERT(is_ground(result));
|
|
m.inc_ref(result);
|
|
for (unsigned i = 0; i < arity; i++) {
|
|
expr * arg = args[i];
|
|
SASSERT(is_ground(arg));
|
|
if (!m.is_value(arg))
|
|
m_args_are_values = false;
|
|
m.inc_ref(arg);
|
|
m_args[i] = arg;
|
|
}
|
|
}
|
|
|
|
func_entry * func_entry::mk(ast_manager & m, unsigned arity, expr * const * args, expr * result) {
|
|
small_object_allocator & allocator = m.get_allocator();
|
|
unsigned sz = get_obj_size(arity);
|
|
void * mem = allocator.allocate(sz);
|
|
return new (mem) func_entry(m, arity, args, result);
|
|
}
|
|
|
|
void func_entry::set_result(ast_manager & m, expr * r) {
|
|
m.inc_ref(r);
|
|
m.dec_ref(m_result);
|
|
m_result = r;
|
|
}
|
|
|
|
bool func_entry::eq_args(unsigned arity, expr * const * args) const {
|
|
unsigned i = 0;
|
|
for (; i < arity; i++) {
|
|
if (m_args[i] != args[i])
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
void func_entry::deallocate(ast_manager & m, unsigned arity) {
|
|
for (unsigned i = 0; i < arity; i++) {
|
|
m.dec_ref(m_args[i]);
|
|
}
|
|
m.dec_ref(m_result);
|
|
small_object_allocator & allocator = m.get_allocator();
|
|
unsigned sz = get_obj_size(arity);
|
|
allocator.deallocate(sz, this);
|
|
}
|
|
|
|
func_interp::func_interp(ast_manager & m, unsigned arity):
|
|
m_manager(m),
|
|
m_arity(arity),
|
|
m_else(0),
|
|
m_args_are_values(true),
|
|
m_interp(0) {
|
|
}
|
|
|
|
func_interp::~func_interp() {
|
|
ptr_vector<func_entry>::iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
curr->deallocate(m_manager, m_arity);
|
|
}
|
|
m_manager.dec_ref(m_else);
|
|
m_manager.dec_ref(m_interp);
|
|
}
|
|
|
|
func_interp * func_interp::copy() const {
|
|
func_interp * new_fi = alloc(func_interp, m_manager, m_arity);
|
|
|
|
ptr_vector<func_entry>::const_iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::const_iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
new_fi->insert_new_entry(curr->get_args(), curr->get_result());
|
|
}
|
|
new_fi->set_else(m_else);
|
|
return new_fi;
|
|
}
|
|
|
|
void func_interp::reset_interp_cache() {
|
|
m_manager.dec_ref(m_interp);
|
|
m_interp = 0;
|
|
}
|
|
|
|
void func_interp::set_else(expr * e) {
|
|
reset_interp_cache();
|
|
m_manager.inc_ref(e);
|
|
m_manager.dec_ref(m_else);
|
|
m_else = e;
|
|
}
|
|
|
|
/**
|
|
\brief Return true if the interpretation represents the constant function.
|
|
*/
|
|
bool func_interp::is_constant() const {
|
|
if (is_partial())
|
|
return false;
|
|
if (!is_ground(m_else))
|
|
return false;
|
|
ptr_vector<func_entry>::const_iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::const_iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
if (curr->get_result() != m_else)
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
\brief Return a func_entry e such that e.m_args[i] == args[i] for all i in [0, m_arity).
|
|
If such entry does not exist then return 0, and store set
|
|
args_are_values to true if for all entries e e.args_are_values() is true.
|
|
*/
|
|
func_entry * func_interp::get_entry(expr * const * args) const {
|
|
ptr_vector<func_entry>::const_iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::const_iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
if (curr->eq_args(m_arity, args))
|
|
return curr;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void func_interp::insert_entry(expr * const * args, expr * r) {
|
|
reset_interp_cache();
|
|
func_entry * entry = get_entry(args);
|
|
if (entry != 0) {
|
|
entry->set_result(m_manager, r);
|
|
return;
|
|
}
|
|
insert_new_entry(args, r);
|
|
}
|
|
|
|
void func_interp::insert_new_entry(expr * const * args, expr * r) {
|
|
reset_interp_cache();
|
|
CTRACE("func_interp_bug", get_entry(args) != 0,
|
|
for (unsigned i = 0; i < m_arity; i++) {
|
|
tout << mk_ismt2_pp(args[i], m_manager) << "\n";
|
|
}
|
|
tout << "Old: " << mk_ismt2_pp(get_entry(args)->m_result, m_manager) << "\n";
|
|
tout << "New: " << mk_ismt2_pp(r, m_manager) << "\n";);
|
|
SASSERT(get_entry(args) == 0);
|
|
func_entry * new_entry = func_entry::mk(m_manager, m_arity, args, r);
|
|
if (!new_entry->args_are_values())
|
|
m_args_are_values = false;
|
|
m_entries.push_back(new_entry);
|
|
}
|
|
|
|
bool func_interp::eval_else(expr * const * args, expr_ref & result) const {
|
|
if (m_else == 0)
|
|
return false;
|
|
var_subst s(m_manager, false);
|
|
SASSERT(!s.std_order()); // (VAR 0) <- args[0], (VAR 1) <- args[1], ...
|
|
s(m_else, m_arity, args, result);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
\brief Store in r the result of applying args to this function.
|
|
Return true in case of success.
|
|
The function may fail if m_else == 0.
|
|
*/
|
|
bool func_interp::eval(simplifier & s, expr * const * args, expr_ref & result) {
|
|
bool actuals_are_values = true;
|
|
|
|
if (!m_entries.empty()) {
|
|
for (unsigned i = 0; actuals_are_values && i < m_arity; i++) {
|
|
actuals_are_values = m_manager.is_value(args[i]);
|
|
}
|
|
}
|
|
|
|
func_entry * entry = get_entry(args);
|
|
if (entry != 0) {
|
|
result = entry->get_result();
|
|
TRACE("func_interp", tout << "found entry for: ";
|
|
for(unsigned i = 0; i < m_arity; i++)
|
|
tout << mk_pp(args[i], m_manager) << " ";
|
|
tout << "\nresult: " << mk_pp(result, m_manager) << "\n";);
|
|
return true;
|
|
}
|
|
|
|
TRACE("func_interp", tout << "failed to find entry for: ";
|
|
for(unsigned i = 0; i < m_arity; i++)
|
|
tout << mk_pp(args[i], m_manager) << " ";
|
|
tout << "\nis partial: " << is_partial() << "\n";);
|
|
|
|
if (!eval_else(args, result)) {
|
|
TRACE("func_interp", tout << "function is partial, failed to evaluate\n";);
|
|
return false;
|
|
}
|
|
|
|
if (actuals_are_values && m_args_are_values) {
|
|
// cheap case... we are done
|
|
return true;
|
|
}
|
|
|
|
|
|
// build symbolic result... the actuals may be equal to the args of one of the entries.
|
|
basic_simplifier_plugin * bs = static_cast<basic_simplifier_plugin*>(s.get_plugin(m_manager.get_basic_family_id()));
|
|
ptr_vector<func_entry>::iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
SASSERT(!curr->eq_args(m_arity, args));
|
|
if (!actuals_are_values || !curr->args_are_values()) {
|
|
expr_ref_buffer eqs(m_manager);
|
|
unsigned i = m_arity;
|
|
while (i > 0) {
|
|
--i;
|
|
expr_ref new_eq(m_manager);
|
|
bs->mk_eq(curr->get_arg(i), args[i], new_eq);
|
|
eqs.push_back(new_eq);
|
|
}
|
|
SASSERT(eqs.size() == m_arity);
|
|
expr_ref new_cond(m_manager);
|
|
bs->mk_and(eqs.size(), eqs.c_ptr(), new_cond);
|
|
bs->mk_ite(new_cond, curr->get_result(), result, result);
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
\brief Return the result with the maximal number of occurrencies in m_entries.
|
|
*/
|
|
expr * func_interp::get_max_occ_result() const {
|
|
if (m_entries.empty())
|
|
return 0;
|
|
obj_map<expr, unsigned> num_occs;
|
|
expr * r_max = 0;
|
|
unsigned max = 0;
|
|
ptr_vector<func_entry>::const_iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::const_iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
expr * r = curr->get_result();
|
|
unsigned occs = 0;
|
|
num_occs.find(r, occs);
|
|
occs++;
|
|
num_occs.insert(r, occs);
|
|
if (occs > max) {
|
|
max = occs;
|
|
r_max = r;
|
|
}
|
|
}
|
|
return r_max;
|
|
}
|
|
|
|
/**
|
|
\brief Remove entries e such that e.get_result() == m_else.
|
|
*/
|
|
void func_interp::compress() {
|
|
if (m_else == 0 || m_entries.empty())
|
|
return; // nothing to be done
|
|
if (!is_ground(m_else))
|
|
return; // forall entries e in m_entries e.get_result() is ground
|
|
unsigned i = 0;
|
|
unsigned j = 0;
|
|
unsigned sz = m_entries.size();
|
|
m_args_are_values = true;
|
|
for (; i < sz; i++) {
|
|
func_entry * curr = m_entries[i];
|
|
if (curr->get_result() != m_else) {
|
|
m_entries[j] = curr;
|
|
j++;
|
|
if (!curr->args_are_values())
|
|
m_args_are_values = false;
|
|
}
|
|
else {
|
|
curr->deallocate(m_manager, m_arity);
|
|
}
|
|
}
|
|
if (j < sz) {
|
|
reset_interp_cache();
|
|
m_entries.shrink(j);
|
|
}
|
|
}
|
|
|
|
expr * func_interp::get_interp_core() const {
|
|
if (m_else == 0)
|
|
return 0;
|
|
expr * r = m_else;
|
|
ptr_buffer<expr> vars;
|
|
ptr_vector<func_entry>::const_iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::const_iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
if (vars.empty()) {
|
|
for (unsigned i = 0; i < m_arity; i++) {
|
|
vars.push_back(m_manager.mk_var(i, m_manager.get_sort(curr->get_arg(i))));
|
|
}
|
|
}
|
|
ptr_buffer<expr> eqs;
|
|
for (unsigned i = 0; i < m_arity; i++) {
|
|
eqs.push_back(m_manager.mk_eq(vars[i], curr->get_arg(i)));
|
|
}
|
|
SASSERT(eqs.size() == m_arity);
|
|
expr * cond;
|
|
if (m_arity == 1)
|
|
cond = eqs.get(0);
|
|
else
|
|
cond = m_manager.mk_and(eqs.size(), eqs.c_ptr());
|
|
r = m_manager.mk_ite(cond, curr->get_result(), r);
|
|
}
|
|
return r;
|
|
}
|
|
|
|
expr * func_interp::get_interp() const {
|
|
if (m_interp != 0)
|
|
return m_interp;
|
|
expr * r = get_interp_core();
|
|
if (r != 0) {
|
|
const_cast<func_interp*>(this)->m_interp = r;
|
|
m_manager.inc_ref(m_interp);
|
|
}
|
|
return r;
|
|
}
|
|
|
|
func_interp * func_interp::translate(ast_translation & translator) const {
|
|
func_interp * new_fi = alloc(func_interp, m_manager, m_arity);
|
|
|
|
ptr_vector<func_entry>::const_iterator it = m_entries.begin();
|
|
ptr_vector<func_entry>::const_iterator end = m_entries.end();
|
|
for (; it != end; ++it) {
|
|
func_entry * curr = *it;
|
|
ptr_buffer<expr> new_args;
|
|
for (unsigned i=0; i<m_arity; i++)
|
|
new_args.push_back(translator(curr->get_arg(i)));
|
|
new_fi->insert_new_entry(new_args.c_ptr(), translator(curr->get_result()));
|
|
}
|
|
new_fi->set_else(translator(m_else));
|
|
return new_fi;
|
|
}
|