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z3/src/muz/base/dl_rule_set.cpp
2016-06-22 20:25:47 -07:00

775 lines
25 KiB
C++

/*++
Copyright (c) 2006 Microsoft Corporation
Module Name:
dl_rule_set.cpp
Abstract:
<abstract>
Author:
Leonardo de Moura (leonardo) 2010-05-17.
Revision History:
--*/
#include<algorithm>
#include<functional>
#include"dl_context.h"
#include"dl_rule_set.h"
#include"ast_pp.h"
namespace datalog {
rule_dependencies::rule_dependencies(context& ctx): m_context(ctx) {
}
rule_dependencies::rule_dependencies(const rule_dependencies & o, bool reversed):
m_context(o.m_context) {
if (reversed) {
iterator oit = o.begin();
iterator oend = o.end();
for (; oit!=oend; ++oit) {
func_decl * pred = oit->m_key;
item_set & orig_items = *oit->get_value();
ensure_key(pred);
item_set::iterator dit = orig_items.begin();
item_set::iterator dend = orig_items.end();
for (; dit!=dend; ++dit) {
func_decl * master_pred = *dit;
insert(master_pred, pred);
}
}
}
else {
iterator oit = o.begin();
iterator oend = o.end();
for (; oit!=oend; ++oit) {
func_decl * pred = oit->m_key;
item_set & orig_items = *oit->get_value();
m_data.insert(pred, alloc(item_set, orig_items));
}
}
}
rule_dependencies::~rule_dependencies() {
reset();
}
void rule_dependencies::reset() {
reset_dealloc_values(m_data);
}
void rule_dependencies::remove_m_data_entry(func_decl * key) {
item_set * itm_set = m_data.find(key);
dealloc(itm_set);
m_data.remove(key);
}
rule_dependencies::item_set & rule_dependencies::ensure_key(func_decl * pred) {
deps_type::obj_map_entry * e = m_data.insert_if_not_there2(pred, 0);
if (!e->get_data().m_value) {
e->get_data().m_value = alloc(item_set);
}
return *e->get_data().m_value;
}
void rule_dependencies::insert(func_decl * depending, func_decl * master) {
SASSERT(m_data.contains(master)); //see m_data documentation
item_set & s = ensure_key(depending);
s.insert(master);
}
void rule_dependencies::populate(const rule_set & rules) {
SASSERT(m_data.empty());
rule_set::decl2rules::iterator it = rules.m_head2rules.begin();
rule_set::decl2rules::iterator end = rules.m_head2rules.end();
for (; it != end; ++it) {
ptr_vector<rule> * rules = it->m_value;
ptr_vector<rule>::iterator it2 = rules->begin();
ptr_vector<rule>::iterator end2 = rules->end();
for (; it2 != end2; ++it2) {
populate(*it2);
}
}
}
void rule_dependencies::populate(unsigned n, rule * const * rules) {
SASSERT(m_data.empty());
for (unsigned i=0; i<n; i++) {
populate(rules[i]);
}
}
void rule_dependencies::populate(rule const* r) {
TRACE("dl_verbose", tout << r->get_decl()->get_name() << "\n";);
m_visited.reset();
func_decl * d = r->get_decl();
func_decl_set & s = ensure_key(d);
for (unsigned i = 0; i < r->get_tail_size(); ++i) {
m_todo.push_back(r->get_tail(i));
}
while (!m_todo.empty()) {
expr* e = m_todo.back();
m_todo.pop_back();
if (m_visited.is_marked(e)) {
continue;
}
m_visited.mark(e, true);
if (is_app(e)) {
app* a = to_app(e);
d = a->get_decl();
if (m_context.is_predicate(d)) {
// insert d and ensure the invariant
// that every predicate is present as
// a key in m_data
s.insert(d);
ensure_key(d);
}
m_todo.append(a->get_num_args(), a->get_args());
}
else if (is_quantifier(e)) {
m_todo.push_back(to_quantifier(e)->get_expr());
}
}
}
const rule_dependencies::item_set & rule_dependencies::get_deps(func_decl * f) const {
deps_type::obj_map_entry * e = m_data.find_core(f);
if (!e) {
return m_empty_item_set;
}
SASSERT(e->get_data().get_value());
return *e->get_data().get_value();
}
void rule_dependencies::restrict(const item_set & allowed) {
ptr_vector<func_decl> to_remove;
iterator pit = begin();
iterator pend = end();
for (; pit!=pend; ++pit) {
func_decl * pred = pit->m_key;
if (!allowed.contains(pred)) {
to_remove.insert(pred);
continue;
}
item_set& itms = *pit->get_value();
set_intersection(itms, allowed);
}
ptr_vector<func_decl>::iterator rit = to_remove.begin();
ptr_vector<func_decl>::iterator rend = to_remove.end();
for (; rit != rend; ++rit) {
remove_m_data_entry(*rit);
}
}
void rule_dependencies::remove(func_decl * itm) {
remove_m_data_entry(itm);
iterator pit = begin();
iterator pend = end();
for (; pit != pend; ++pit) {
item_set & itms = *pit->get_value();
itms.remove(itm);
}
}
void rule_dependencies::remove(const item_set & to_remove) {
item_set::iterator rit = to_remove.begin();
item_set::iterator rend = to_remove.end();
for (; rit!=rend; ++rit) {
remove_m_data_entry(*rit);
}
iterator pit = begin();
iterator pend = end();
for (; pit!=pend; ++pit) {
item_set * itms = pit->get_value();
set_difference(*itms, to_remove);
}
}
unsigned rule_dependencies::out_degree(func_decl * f) const {
unsigned res = 0;
iterator pit = begin();
iterator pend = end();
for (; pit!=pend; ++pit) {
item_set & itms = *pit->get_value();
if (itms.contains(f)) {
res++;
}
}
return res;
}
bool rule_dependencies::sort_deps(ptr_vector<func_decl> & res) {
typedef obj_map<func_decl, unsigned> deg_map;
unsigned init_len = res.size();
deg_map degs;
unsigned curr_index = init_len;
rule_dependencies reversed(*this, true);
iterator pit = begin();
iterator pend = end();
for (; pit!=pend; ++pit) {
func_decl * pred = pit->m_key;
unsigned deg = in_degree(pred);
if (deg==0) {
res.push_back(pred);
}
else {
degs.insert(pred, deg);
}
}
while (curr_index<res.size()) { //res.size() can change in the loop iteration
func_decl * curr = res[curr_index];
const item_set & children = reversed.get_deps(curr);
item_set::iterator cit = children.begin();
item_set::iterator cend = children.end();
for (; cit!=cend; ++cit) {
func_decl * child = *cit;
deg_map::obj_map_entry * e = degs.find_core(child);
SASSERT(e);
unsigned & child_deg = e->get_data().m_value;
SASSERT(child_deg>0);
child_deg--;
if (child_deg==0) {
res.push_back(child);
}
}
curr_index++;
}
if (res.size() < init_len + m_data.size()) {
res.shrink(init_len);
return false;
}
SASSERT(res.size()==init_len+m_data.size());
return true;
}
void rule_dependencies::display(std::ostream & out ) const
{
iterator pit = begin();
iterator pend = end();
for (; pit != pend; ++pit) {
func_decl * pred = pit->m_key;
const item_set & deps = *pit->m_value;
item_set::iterator dit=deps.begin();
item_set::iterator dend=deps.end();
if (dit == dend) {
out<<pred->get_name()<<" - <none>\n";
}
for (; dit != dend; ++dit) {
func_decl * dep = *dit;
out << pred->get_name() << " -> " << dep->get_name() << "\n";
}
}
}
// -----------------------------------
//
// rule_set
//
// -----------------------------------
rule_set::rule_set(context & ctx)
: m_context(ctx),
m_rule_manager(ctx.get_rule_manager()),
m_rules(m_rule_manager),
m_deps(ctx),
m_stratifier(0),
m_refs(ctx.get_manager()) {
}
rule_set::rule_set(const rule_set & other)
: m_context(other.m_context),
m_rule_manager(other.m_rule_manager),
m_rules(m_rule_manager),
m_deps(other.m_context),
m_stratifier(0),
m_refs(m_context.get_manager()) {
add_rules(other);
if (other.m_stratifier) {
VERIFY(close());
}
}
rule_set::~rule_set() {
reset();
}
void rule_set::reset() {
m_rules.reset();
reset_dealloc_values(m_head2rules);
m_deps.reset();
m_stratifier = 0;
m_output_preds.reset();
m_orig2pred.reset();
m_pred2orig.reset();
m_refs.reset();
}
ast_manager & rule_set::get_manager() const {
return m_context.get_manager();
}
func_decl* rule_set::get_orig(func_decl* pred) const {
func_decl* orig = pred;
m_pred2orig.find(pred, orig);
return orig;
}
func_decl* rule_set::get_pred(func_decl* orig) const {
func_decl* pred = orig;
m_orig2pred.find(orig, pred);
return pred;
}
void rule_set::inherit_predicates(rule_set const& other) {
m_refs.append(other.m_refs);
set_union(m_output_preds, other.m_output_preds);
{
obj_map<func_decl, func_decl*>::iterator it = other.m_orig2pred.begin();
obj_map<func_decl, func_decl*>::iterator end = other.m_orig2pred.end();
for (; it != end; ++it) {
m_orig2pred.insert(it->m_key, it->m_value);
}
}
{
obj_map<func_decl, func_decl*>::iterator it = other.m_pred2orig.begin();
obj_map<func_decl, func_decl*>::iterator end = other.m_pred2orig.end();
for (; it != end; ++it) {
m_pred2orig.insert(it->m_key, it->m_value);
}
}
}
void rule_set::inherit_predicate(rule_set const& other, func_decl* orig, func_decl* pred) {
if (other.is_output_predicate(orig)) {
set_output_predicate(pred);
}
orig = other.get_orig(orig);
m_refs.push_back(pred);
m_refs.push_back(orig);
m_orig2pred.insert(orig, pred);
m_pred2orig.insert(pred, orig);
}
void rule_set::add_rule(rule * r) {
TRACE("dl_verbose", r->display(m_context, tout << "add:"););
SASSERT(!is_closed());
m_rules.push_back(r);
app * head = r->get_head();
SASSERT(head != 0);
func_decl * d = head->get_decl();
decl2rules::obj_map_entry* e = m_head2rules.insert_if_not_there2(d, 0);
if (!e->get_data().m_value) e->get_data().m_value = alloc(ptr_vector<rule>);
e->get_data().m_value->push_back(r);
}
void rule_set::del_rule(rule * r) {
TRACE("dl", r->display(m_context, tout << "del:"););
func_decl* d = r->get_decl();
rule_vector* rules = m_head2rules.find(d);
#define DEL_VECTOR(_v) \
for (unsigned i = (_v).size(); i > 0; ) { \
--i; \
if ((_v)[i] == r) { \
(_v)[i] = (_v).back(); \
(_v).pop_back(); \
break; \
} \
} \
DEL_VECTOR(*rules);
DEL_VECTOR(m_rules);
}
void rule_set::ensure_closed() {
if (!is_closed()) {
VERIFY(close());
}
}
bool rule_set::close() {
SASSERT(!is_closed()); //the rule_set is not already closed
m_deps.populate(*this);
m_stratifier = alloc(rule_stratifier, m_deps);
if (!stratified_negation()) {
m_stratifier = 0;
m_deps.reset();
return false;
}
return true;
}
void rule_set::reopen() {
if (is_closed()) {
m_stratifier = 0;
m_deps.reset();
}
}
/**
\brief Return true if the negation is indeed stratified.
*/
bool rule_set::stratified_negation() {
ptr_vector<rule>::const_iterator it = m_rules.c_ptr();
ptr_vector<rule>::const_iterator end = m_rules.c_ptr()+m_rules.size();
for (; it != end; it++) {
rule * r = *it;
app * head = r->get_head();
func_decl * head_decl = head->get_decl();
unsigned n = r->get_uninterpreted_tail_size();
for (unsigned i = r->get_positive_tail_size(); i < n; i++) {
SASSERT(r->is_neg_tail(i));
func_decl * tail_decl = r->get_tail(i)->get_decl();
unsigned neg_strat = get_predicate_strat(tail_decl);
unsigned head_strat = get_predicate_strat(head_decl);
SASSERT(head_strat>=neg_strat); //head strat can never be lower than that of a tail
if (head_strat == neg_strat) {
return false;
}
}
}
return true;
}
void rule_set::replace_rules(const rule_set & src) {
if (this != &src) {
reset();
add_rules(src);
}
}
void rule_set::add_rules(const rule_set & src) {
SASSERT(!is_closed());
unsigned n = src.get_num_rules();
for (unsigned i = 0; i < n; i++) {
add_rule(src.get_rule(i));
}
inherit_predicates(src);
}
const rule_vector & rule_set::get_predicate_rules(func_decl * pred) const {
decl2rules::obj_map_entry * e = m_head2rules.find_core(pred);
if (!e) {
return m_empty_rule_vector;
}
return *e->get_data().m_value;
}
const rule_set::pred_set_vector & rule_set::get_strats() const {
SASSERT(m_stratifier);
return m_stratifier->get_strats();
}
unsigned rule_set::get_predicate_strat(func_decl * pred) const {
SASSERT(m_stratifier);
return m_stratifier->get_predicate_strat(pred);
}
void rule_set::split_founded_rules(func_decl_set& founded, func_decl_set& non_founded) {
founded.reset();
non_founded.reset();
{
decl2rules::iterator it = begin_grouped_rules(), end = end_grouped_rules();
for (; it != end; ++it) {
non_founded.insert(it->m_key);
}
}
bool change = true;
while (change) {
change = false;
func_decl_set::iterator it = non_founded.begin(), end = non_founded.end();
for (; it != end; ++it) {
rule_vector const& rv = get_predicate_rules(*it);
bool found = false;
for (unsigned i = 0; !found && i < rv.size(); ++i) {
rule const& r = *rv[i];
bool is_founded = true;
for (unsigned j = 0; is_founded && j < r.get_uninterpreted_tail_size(); ++j) {
is_founded = founded.contains(r.get_decl(j));
}
if (is_founded) {
founded.insert(*it);
non_founded.remove(*it);
change = true;
found = true;
}
}
}
}
}
void rule_set::display(std::ostream & out) const {
out << "; rule count: " << get_num_rules() << "\n";
out << "; predicate count: " << m_head2rules.size() << "\n";
func_decl_set::iterator pit = m_output_preds.begin();
func_decl_set::iterator pend = m_output_preds.end();
for (; pit != pend; ++pit) {
out << "; output: " << (*pit)->get_name() << '\n';
}
decl2rules::iterator it = m_head2rules.begin();
decl2rules::iterator end = m_head2rules.end();
for (; it != end; ++it) {
ptr_vector<rule> * rules = it->m_value;
ptr_vector<rule>::iterator it2 = rules->begin();
ptr_vector<rule>::iterator end2 = rules->end();
for (; it2 != end2; ++it2) {
rule * r = *it2;
if (!r->passes_output_thresholds(m_context)) {
continue;
}
r->display(m_context, out);
}
}
}
void rule_set::display_deps( std::ostream & out ) const
{
const pred_set_vector & strats = get_strats();
pred_set_vector::const_iterator sit = strats.begin();
pred_set_vector::const_iterator send = strats.end();
for (; sit!=send; ++sit) {
func_decl_set & strat = **sit;
func_decl_set::iterator fit=strat.begin();
func_decl_set::iterator fend=strat.end();
bool non_empty = false;
for (; fit!=fend; ++fit) {
func_decl * first = *fit;
const func_decl_set & deps = m_deps.get_deps(first);
func_decl_set::iterator dit=deps.begin();
func_decl_set::iterator dend=deps.end();
for (; dit!=dend; ++dit) {
non_empty = true;
func_decl * dep = *dit;
out<<first->get_name()<<" -> "<<dep->get_name()<<"\n";
}
}
if (non_empty && sit!=send) {
out << "\n";
}
}
}
// -----------------------------------
//
// rule_stratifier
//
// -----------------------------------
rule_stratifier::~rule_stratifier() {
comp_vector::iterator it = m_strats.begin();
comp_vector::iterator end = m_strats.end();
for (; it!=end; ++it) {
SASSERT(*it);
dealloc(*it);
}
}
unsigned rule_stratifier::get_predicate_strat(func_decl * pred) const {
unsigned num;
if (!m_pred_strat_nums.find(pred, num)) {
//the number of the predicate is not stored, therefore it did not appear
//in the algorithm and therefore it does not depend on anything and nothing
//depends on it. So it is safe to assign zero strate to it, although it is
//not strictly true.
num = 0;
}
return num;
}
void rule_stratifier::traverse(T* el) {
unsigned p_num;
if (m_preorder_nums.find(el, p_num)) {
if (p_num < m_first_preorder) {
//traversed in a previous sweep
return;
}
if (m_component_nums.contains(el)) {
//we already assigned a component for el
return;
}
while (!m_stack_P.empty()) {
unsigned on_stack_num = 0;
VERIFY( m_preorder_nums.find(m_stack_P.back(), on_stack_num) );
if (on_stack_num <= p_num) {
break;
}
m_stack_P.pop_back();
}
}
else {
p_num=m_next_preorder++;
m_preorder_nums.insert(el, p_num);
m_stack_S.push_back(el);
m_stack_P.push_back(el);
const item_set & children = m_deps.get_deps(el);
item_set::iterator cit=children.begin();
item_set::iterator cend=children.end();
for (; cit!=cend; ++cit) {
traverse(*cit);
}
if (el == m_stack_P.back()) {
unsigned comp_num = m_components.size();
item_set * new_comp = alloc(item_set);
m_components.push_back(new_comp);
T* s_el;
do {
s_el=m_stack_S.back();
m_stack_S.pop_back();
new_comp->insert(s_el);
m_component_nums.insert(s_el, comp_num);
} while (s_el!=el);
m_stack_P.pop_back();
}
}
}
void rule_stratifier::process() {
if (m_deps.empty()) {
return;
}
//detect strong components
rule_dependencies::iterator it = m_deps.begin();
rule_dependencies::iterator end = m_deps.end();
for (; it!=end; ++it) {
T * el = it->m_key;
//we take a note of the preorder number with which this sweep started
m_first_preorder = m_next_preorder;
traverse(el);
}
//do topological sorting
//degres of components (number of inter-component edges ending up in the component)
svector<unsigned> in_degrees;
in_degrees.resize(m_components.size());
//init in_degrees
it = m_deps.begin();
end = m_deps.end();
for (; it != end; ++it) {
T * el = it->m_key;
item_set * out_edges = it->m_value;
unsigned el_comp;
VERIFY( m_component_nums.find(el, el_comp) );
item_set::iterator eit = out_edges->begin();
item_set::iterator eend = out_edges->end();
for (; eit!=eend; ++eit) {
T * tgt = *eit;
unsigned tgt_comp = m_component_nums.find(tgt);
if (el_comp != tgt_comp) {
in_degrees[tgt_comp]++;
}
}
}
// We put components whose indegree is zero to m_strats and assign its
// m_components entry to zero.
unsigned comp_cnt = m_components.size();
for (unsigned i = 0; i < comp_cnt; i++) {
if (in_degrees[i] == 0) {
m_strats.push_back(m_components[i]);
m_components[i] = 0;
}
}
SASSERT(!m_strats.empty()); //the component graph is acyclic and non-empty
//we remove edges from components with zero indegre building the topological ordering
unsigned strats_index = 0;
while (strats_index < m_strats.size()) { //m_strats.size() changes inside the loop!
item_set * comp = m_strats[strats_index];
item_set::iterator cit=comp->begin();
item_set::iterator cend=comp->end();
for (; cit!=cend; ++cit) {
T * el = *cit;
const item_set & deps = m_deps.get_deps(el);
item_set::iterator eit=deps.begin();
item_set::iterator eend=deps.end();
for (; eit!=eend; ++eit) {
T * tgt = *eit;
unsigned tgt_comp = 0;
VERIFY( m_component_nums.find(tgt, tgt_comp) );
//m_components[tgt_comp]==0 means the edge is intra-component.
//Otherwise it would go to another component, but it is not possible, since
//as m_components[tgt_comp]==0, its indegree has already reached zero.
if (m_components[tgt_comp]) {
SASSERT(in_degrees[tgt_comp]>0);
in_degrees[tgt_comp]--;
if (in_degrees[tgt_comp]==0) {
m_strats.push_back(m_components[tgt_comp]);
m_components[tgt_comp] = 0;
}
}
traverse(*cit);
}
}
strats_index++;
}
//we have managed to topologicaly order all the components
SASSERT(std::find_if(m_components.begin(), m_components.end(),
std::bind1st(std::not_equal_to<item_set*>(), (item_set*)0)) == m_components.end());
//reverse the strats array, so that the only the later components would depend on earlier ones
std::reverse(m_strats.begin(), m_strats.end());
SASSERT(m_pred_strat_nums.empty());
unsigned strat_cnt = m_strats.size();
for (unsigned strat_index=0; strat_index<strat_cnt; strat_index++) {
item_set * comp = m_strats[strat_index];
item_set::iterator cit=comp->begin();
item_set::iterator cend=comp->end();
for (; cit != cend; ++cit) {
T * el = *cit;
m_pred_strat_nums.insert(el, strat_index);
}
}
//finalize structures that are not needed anymore
m_preorder_nums.finalize();
m_stack_S.finalize();
m_stack_P.finalize();
m_component_nums.finalize();
m_components.finalize();
}
void rule_stratifier::display(std::ostream& out) const {
m_deps.display(out << "dependencies\n");
out << "strata\n";
for (unsigned i = 0; i < m_strats.size(); ++i) {
item_set::iterator it = m_strats[i]->begin();
item_set::iterator end = m_strats[i]->end();
for (; it != end; ++it) {
out << (*it)->get_name() << " ";
}
out << "\n";
}
}
};