z3-z3-4.13.0.src.muz.transforms.dl_mk_synchronize.cpp Maven / Gradle / Ivy
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/*++
Copyright (c) 2017-2018 Saint-Petersburg State University
Module Name:
dl_mk_synchronize.h
Abstract:
Rule transformer that attempts to merge recursive iterations
relaxing the shape of the inductive invariant.
Author:
Dmitry Mordvinov (dvvrd) 2017-05-24
Lidiia Chernigovskaia (LChernigovskaya) 2017-10-20
Revision History:
--*/
#include "muz/transforms/dl_mk_synchronize.h"
#include
namespace datalog {
typedef mk_synchronize::item_set_vector item_set_vector;
mk_synchronize::mk_synchronize(context& ctx, unsigned priority):
rule_transformer::plugin(priority, false),
m_ctx(ctx),
m(ctx.get_manager()),
rm(ctx.get_rule_manager())
{}
bool mk_synchronize::is_recursive(rule &r, func_decl &decl) const {
func_decl *hdecl = r.get_head()->get_decl();
// AG: shouldn't decl appear in the body?
if (hdecl == &decl) return true;
auto & strata = m_stratifier->get_strats();
unsigned num_of_stratum = m_stratifier->get_predicate_strat(hdecl);
return strata[num_of_stratum]->contains(&decl);
}
bool mk_synchronize::has_recursive_premise(app * app) const {
func_decl* app_decl = app->get_decl();
if (m_deps->get_deps(app_decl).contains(app_decl)) {
return true;
}
rule_stratifier::comp_vector const & strata = m_stratifier->get_strats();
unsigned num_of_stratum = m_stratifier->get_predicate_strat(app_decl);
return strata[num_of_stratum]->size() > 1;
}
item_set_vector mk_synchronize::add_merged_decls(ptr_vector & apps) {
unsigned sz = apps.size();
item_set_vector merged_decls;
merged_decls.resize(sz);
auto & strata = m_stratifier->get_strats();
for (unsigned j = 0; j < sz; ++j) {
unsigned nos;
nos = m_stratifier->get_predicate_strat(apps[j]->get_decl());
merged_decls[j] = strata[nos];
}
return merged_decls;
}
void mk_synchronize::add_new_rel_symbols(unsigned idx,
item_set_vector const & decls,
ptr_vector & decls_buf,
bool & was_added) {
if (idx >= decls.size()) {
string_buffer<> buffer;
ptr_vector domain;
for (auto &d : decls_buf) {
buffer << d->get_name() << "!!";
domain.append(d->get_arity(), d->get_domain());
}
symbol new_name = symbol(buffer.c_str());
if (!m_cache.contains(new_name)) {
was_added = true;
func_decl* orig = decls_buf[0];
func_decl* product_pred = m_ctx.mk_fresh_head_predicate(new_name,
symbol::null, domain.size(), domain.data(), orig);
m_cache.insert(new_name, product_pred);
}
return;
}
// -- compute Cartesian product of decls, and create a new
// -- predicate for each element of the product
for (auto &p : *decls[idx]) {
decls_buf[idx] = p;
add_new_rel_symbols(idx + 1, decls, decls_buf, was_added);
}
}
void mk_synchronize::replace_applications(rule & r, rule_set & rules,
ptr_vector & apps) {
app_ref replacing = product_application(apps);
ptr_vector new_tail;
bool_vector new_tail_neg;
unsigned n = r.get_tail_size() - apps.size() + 1;
unsigned tail_idx = 0;
new_tail.resize(n);
new_tail_neg.resize(n);
new_tail[0] = replacing;
new_tail_neg[0] = false;
for (unsigned i = 0; i < r.get_positive_tail_size(); ++i) {
app* tail = r.get_tail(i);
if (!apps.contains(tail)) {
++tail_idx;
new_tail[tail_idx] = tail;
new_tail_neg[tail_idx] = false;
}
}
for (unsigned i = r.get_positive_tail_size(); i < r.get_uninterpreted_tail_size(); ++i) {
++tail_idx;
new_tail[tail_idx] = r.get_tail(i);
new_tail_neg[tail_idx] = true;
}
for (unsigned i = r.get_uninterpreted_tail_size(); i < r.get_tail_size(); ++i) {
++tail_idx;
new_tail[tail_idx] = r.get_tail(i);
new_tail_neg[tail_idx] = false;
}
rule_ref new_rule(rm);
new_rule = rm.mk(r.get_head(), tail_idx + 1,
new_tail.data(), new_tail_neg.data(), symbol::null, false);
rules.replace_rule(&r, new_rule.get());
}
rule_ref mk_synchronize::rename_bound_vars_in_rule(rule * r,
unsigned & var_idx) {
// AG: shift all variables in a rule so that lowest var index is var_idx?
// AG: update var_idx in the process?
ptr_vector sorts;
r->get_vars(m, sorts);
expr_ref_vector revsub(m);
revsub.resize(sorts.size());
for (unsigned i = 0; i < sorts.size(); ++i) {
if (sorts[i]) {
revsub[i] = m.mk_var(var_idx++, sorts[i]);
}
}
rule_ref new_rule(rm);
new_rule = rm.mk(r);
rm.substitute(new_rule, revsub.size(), revsub.data());
return new_rule;
}
vector mk_synchronize::rename_bound_vars(item_set_vector const & heads,
rule_set & rules) {
// AG: is every item_set in heads corresponds to rules that are merged?
// AG: why are bound variables renamed in the first place?
// AG: the data structure seems too complex
vector result;
unsigned var_idx = 0;
for (auto item : heads) {
rule_ref_vector dst_vector(rm);
for (auto *head : *item) {
for (auto *r : rules.get_predicate_rules(head)) {
rule_ref new_rule = rename_bound_vars_in_rule(r, var_idx);
dst_vector.push_back(new_rule.get());
}
}
result.push_back(dst_vector);
}
return result;
}
void mk_synchronize::add_rec_tail(vector< ptr_vector > & recursive_calls,
app_ref_vector & new_tail,
bool_vector & new_tail_neg,
unsigned & tail_idx) {
unsigned max_sz = 0;
for (auto &rc : recursive_calls)
max_sz= std::max(rc.size(), max_sz);
unsigned n = recursive_calls.size();
ptr_vector merged_recursive_calls;
for (unsigned j = 0; j < max_sz; ++j) {
merged_recursive_calls.reset();
merged_recursive_calls.resize(n);
for (unsigned i = 0; i < n; ++i) {
unsigned sz = recursive_calls[i].size();
merged_recursive_calls[i] =
j < sz ? recursive_calls[i][j] : recursive_calls[i][sz - 1];
}
++tail_idx;
new_tail[tail_idx] = product_application(merged_recursive_calls);
new_tail_neg[tail_idx] = false;
}
}
void mk_synchronize::add_non_rec_tail(rule & r, app_ref_vector & new_tail,
bool_vector & new_tail_neg,
unsigned & tail_idx) {
for (unsigned i = 0, sz = r.get_positive_tail_size(); i < sz; ++i) {
app* tail = r.get_tail(i);
if (!is_recursive(r, *tail)) {
++tail_idx;
new_tail[tail_idx] = tail;
new_tail_neg[tail_idx] = false;
}
}
for (unsigned i = r.get_positive_tail_size(),
sz = r.get_uninterpreted_tail_size() ; i < sz; ++i) {
++tail_idx;
new_tail[tail_idx] = r.get_tail(i);
new_tail_neg[tail_idx] = true;
}
for (unsigned i = r.get_uninterpreted_tail_size(),
sz = r.get_tail_size(); i < sz; ++i) {
++tail_idx;
new_tail[tail_idx] = r.get_tail(i);
new_tail_neg[tail_idx] = r.is_neg_tail(i);
}
}
app_ref mk_synchronize::product_application(ptr_vector const &apps) {
unsigned args_num = 0;
string_buffer<> buffer;
// AG: factor out into mk_name
for (auto *app : apps) {
buffer << app->get_decl()->get_name() << "!!";
args_num += app->get_num_args();
}
symbol name = symbol(buffer.c_str());
SASSERT(m_cache.contains(name));
func_decl * pred = m_cache[name];
ptr_vector args;
args.resize(args_num);
unsigned idx = 0;
for (auto *a : apps) {
for (unsigned i = 0, sz = a->get_num_args(); i < sz; ++i, ++idx)
args[idx] = a->get_arg(i);
}
return app_ref(m.mk_app(pred, args_num, args.data()), m);
}
rule_ref mk_synchronize::product_rule(rule_ref_vector const & rules) {
unsigned n = rules.size();
string_buffer<> buffer;
bool first_rule = true;
for (auto it = rules.begin(); it != rules.end(); ++it, first_rule = false) {
if (!first_rule) {
buffer << "+";
}
buffer << (*it)->name();
}
ptr_vector heads;
heads.resize(n);
for (unsigned i = 0; i < n; ++i) {
heads[i] = rules[i]->get_head();
}
app_ref product_head = product_application(heads);
unsigned product_tail_length = 0;
bool has_recursion = false;
vector< ptr_vector > recursive_calls;
recursive_calls.resize(n);
for (unsigned i = 0; i < n; ++i) {
rule& rule = *rules[i];
product_tail_length += rule.get_tail_size();
for (unsigned j = 0; j < rule.get_positive_tail_size(); ++j) {
app* tail = rule.get_tail(j);
if (is_recursive(rule, *tail)) {
has_recursion = true;
recursive_calls[i].push_back(tail);
}
}
if (recursive_calls[i].empty()) {
recursive_calls[i].push_back(rule.get_head());
}
}
app_ref_vector new_tail(m);
bool_vector new_tail_neg;
new_tail.resize(product_tail_length);
new_tail_neg.resize(product_tail_length);
unsigned tail_idx = -1;
if (has_recursion) {
add_rec_tail(recursive_calls, new_tail, new_tail_neg, tail_idx);
}
for (rule_vector::const_iterator it = rules.begin(); it != rules.end(); ++it) {
rule& rule = **it;
add_non_rec_tail(rule, new_tail, new_tail_neg, tail_idx);
}
rule_ref new_rule(rm);
new_rule = rm.mk(product_head, tail_idx + 1,
new_tail.data(), new_tail_neg.data(), symbol(buffer.c_str()), false);
rm.fix_unbound_vars(new_rule, false);
return new_rule;
}
void mk_synchronize::merge_rules(unsigned idx, rule_ref_vector & buf,
vector const & merged_rules,
rule_set & all_rules) {
if (idx >= merged_rules.size()) {
rule_ref product = product_rule(buf);
all_rules.add_rule(product.get());
return;
}
for (auto *r : merged_rules[idx]) {
buf[idx] = r;
merge_rules(idx + 1, buf, merged_rules, all_rules);
}
}
void mk_synchronize::merge_applications(rule & r, rule_set & rules) {
ptr_vector non_recursive_preds;
obj_hashtable apps;
for (unsigned i = 0; i < r.get_positive_tail_size(); ++i) {
app* t = r.get_tail(i);
if (!is_recursive(r, *t) && has_recursive_premise(t)) {
apps.insert(t);
}
}
if (apps.size() < 2) return;
for (auto *a : apps) non_recursive_preds.push_back(a);
item_set_vector merged_decls = add_merged_decls(non_recursive_preds);
unsigned n = non_recursive_preds.size();
ptr_vector decls_buf;
decls_buf.resize(n);
bool was_added = false;
add_new_rel_symbols(0, merged_decls, decls_buf, was_added);
if (was_added){
rule_ref_vector rules_buf(rm);
rules_buf.resize(n);
vector renamed_rules = rename_bound_vars(merged_decls, rules);
merge_rules(0, rules_buf, renamed_rules, rules);
}
replace_applications(r, rules, non_recursive_preds);
m_deps->populate(rules);
m_stratifier = alloc(rule_stratifier, *m_deps);
}
rule_set * mk_synchronize::operator()(rule_set const & source) {
rule_set* rules = alloc(rule_set, m_ctx);
rules->inherit_predicates(source);
for (auto *r : source) { rules->add_rule(r); }
m_deps = alloc(rule_dependencies, m_ctx);
m_deps->populate(*rules);
m_stratifier = alloc(rule_stratifier, *m_deps);
unsigned current_rule = 0;
while (current_rule < rules->get_num_rules()) {
rule *r = rules->get_rule(current_rule);
merge_applications(*r, *rules);
++current_rule;
}
return rules;
}
};