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Added limit to "visit" to allow detecting multiple visits (#6435)

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* Memory leak in .NET user-propagator
The user-propagator object has to be manually disposed (IDisposable), otherwise it stays in memory forever, as it cannot be garbage collected automatically

* Throw an exception if variable passed to decide is already assigned instead of running in an assertion violation

* Added limit to "visit" to allow detecting multiple visits

* Putting visit in a separate class
(Reason: We will probably need two of them in the sat::solver)

* Bugfix
This commit is contained in:
Clemens Eisenhofer 2022-11-03 11:34:52 +01:00 committed by GitHub
parent e0bbe8dfc0
commit 6790f18132
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GPG key ID: 4AEE18F83AFDEB23
7 changed files with 68 additions and 52 deletions
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4
src/sat/sat_gc.cpp
View file

@ -406,9 +406,9 @@ namespace sat {
auto gc_watch = [&](literal lit) {
auto& wl1 = get_wlist(lit);
for (auto w : get_wlist(lit)) {
if (w.is_binary_clause() && w.get_literal().var() < max_var && !is_visited(w.get_literal())) {
if (w.is_binary_clause() && w.get_literal().var() < max_var && !m_visited.is_visited(w.get_literal())) {
m_aux_literals.push_back(w.get_literal());
mark_visited(w.get_literal());
m_visited.mark_visited(w.get_literal());
}
}
wl1.reset();

12
src/sat/sat_lut_finder.cpp
View file

@ -70,7 +70,7 @@ namespace sat {
for (literal l : m_clause) {
m_vars.push_back(l.var());
m_var_position[l.var()] = i;
s.mark_visited(l.var());
s.m_visited.mark_visited(l.var());
mask |= (l.sign() << (i++));
}
m_clauses_to_remove.reset();
@ -91,7 +91,7 @@ namespace sat {
// TBD: replace by BIG
// loop over binary clauses in watch list
for (watched const & w : s.get_wlist(l)) {
if (w.is_binary_clause() && s.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (w.is_binary_clause() && s.m_visited.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (extract_lut(~l, w.get_literal())) {
add_lut();
return;
@ -100,7 +100,7 @@ namespace sat {
}
l.neg();
for (watched const & w : s.get_wlist(l)) {
if (w.is_binary_clause() && s.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (w.is_binary_clause() && s.m_visited.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (extract_lut(~l, w.get_literal())) {
add_lut();
return;
@ -124,8 +124,8 @@ namespace sat {
}
bool lut_finder::extract_lut(literal l1, literal l2) {
SASSERT(s.is_visited(l1.var()));
SASSERT(s.is_visited(l2.var()));
SASSERT(s.m_visited.is_visited(l1.var()));
SASSERT(s.m_visited.is_visited(l2.var()));
m_missing.reset();
unsigned mask = 0;
for (unsigned i = 0; i < m_vars.size(); ++i) {
@ -144,7 +144,7 @@ namespace sat {
bool lut_finder::extract_lut(clause& c2) {
for (literal l : c2) {
if (!s.is_visited(l.var()))
if (!s.m_visited.is_visited(l.var()))
return false;
}
if (c2.size() == m_vars.size()) {

32
src/sat/sat_solver.cpp
View file

@ -3441,10 +3441,10 @@ namespace sat {
for (unsigned i = m_clauses_to_reinit.size(); i-- > old_sz; ) {
clause_wrapper const& cw = m_clauses_to_reinit[i];
for (unsigned j = cw.size(); j-- > 0; )
mark_visited(cw[j].var());
m_visited.mark_visited(cw[j].var());
}
for (literal lit : m_lemma)
mark_visited(lit.var());
m_visited.mark_visited(lit.var());
auto is_active = [&](bool_var v) {
return value(v) != l_undef && lvl(v) <= new_lvl;
@ -3452,7 +3452,7 @@ namespace sat {
for (unsigned i = old_num_vars; i < sz; ++i) {
bool_var v = m_active_vars[i];
if (is_external(v) || is_visited(v) || is_active(v)) {
if (is_external(v) || m_visited.is_visited(v) || is_active(v)) {
m_vars_to_reinit.push_back(v);
m_active_vars[j++] = v;
m_var_scope[v] = new_lvl;
@ -4697,10 +4697,10 @@ namespace sat {
bool solver::all_distinct(literal_vector const& lits) {
init_visited();
for (literal l : lits) {
if (is_visited(l.var())) {
if (m_visited.is_visited(l.var())) {
return false;
}
mark_visited(l.var());
m_visited.mark_visited(l.var());
}
return true;
}
@ -4708,30 +4708,12 @@ namespace sat {
bool solver::all_distinct(clause const& c) {
init_visited();
for (literal l : c) {
if (is_visited(l.var())) {
if (m_visited.is_visited(l.var())) {
return false;
}
mark_visited(l.var());
m_visited.mark_visited(l.var());
}
return true;
}
void solver::init_ts(unsigned n, svector<unsigned>& v, unsigned& ts) {
if (v.empty())
ts = 0;
ts++;
if (ts == 0) {
ts = 1;
v.reset();
}
while (v.size() < n)
v.push_back(0);
}
void solver::init_visited() {
init_ts(2 * num_vars(), m_visited, m_visited_ts);
}
};

13
src/sat/sat_solver.h
View file

@ -28,6 +28,7 @@ Revision History:
#include "util/rlimit.h"
#include "util/scoped_ptr_vector.h"
#include "util/scoped_limit_trail.h"
#include "util/visit_helper.h"
#include "sat/sat_types.h"
#include "sat/sat_clause.h"
#include "sat/sat_watched.h"
@ -176,8 +177,7 @@ namespace sat {
std::string m_reason_unknown;
bool m_trim = false;
svector<unsigned> m_visited;
unsigned m_visited_ts;
visit_helper m_visited;
struct scope {
unsigned m_trail_lim;
@ -342,13 +342,8 @@ namespace sat {
void detach_nary_clause(clause & c);
void push_reinit_stack(clause & c);
void push_reinit_stack(literal l1, literal l2);
void init_ts(unsigned n, svector<unsigned>& v, unsigned& ts);
void init_visited();
void mark_visited(literal l) { m_visited[l.index()] = m_visited_ts; }
void mark_visited(bool_var v) { mark_visited(literal(v, false)); }
bool is_visited(bool_var v) const { return is_visited(literal(v, false)); }
bool is_visited(literal l) const { return m_visited[l.index()] == m_visited_ts; }
void init_visited(unsigned lim = 1) { m_visited.init_visited(num_vars(), lim); }
bool all_distinct(literal_vector const& lits);
bool all_distinct(clause const& cl);

12
src/sat/sat_xor_finder.cpp
View file

@ -62,7 +62,7 @@ namespace sat {
unsigned mask = 0, i = 0;
for (literal l : c) {
m_var_position[l.var()] = i;
s.mark_visited(l.var());
s.m_visited.mark_visited(l.var());
parity ^= !l.sign();
mask |= (!l.sign() << (i++));
}
@ -84,7 +84,7 @@ namespace sat {
}
// loop over binary clauses in watch list
for (watched const & w : s.get_wlist(l)) {
if (w.is_binary_clause() && s.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (w.is_binary_clause() && s.m_visited.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (extract_xor(parity, c, ~l, w.get_literal())) {
add_xor(parity, c);
return;
@ -93,7 +93,7 @@ namespace sat {
}
l.neg();
for (watched const & w : s.get_wlist(l)) {
if (w.is_binary_clause() && s.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (w.is_binary_clause() && s.m_visited.is_visited(w.get_literal().var()) && w.get_literal().index() < l.index()) {
if (extract_xor(parity, c, ~l, w.get_literal())) {
add_xor(parity, c);
return;
@ -122,8 +122,8 @@ namespace sat {
}
bool xor_finder::extract_xor(bool parity, clause& c, literal l1, literal l2) {
SASSERT(s.is_visited(l1.var()));
SASSERT(s.is_visited(l2.var()));
SASSERT(s.m_visited.is_visited(l1.var()));
SASSERT(s.m_visited.is_visited(l2.var()));
m_missing.reset();
unsigned mask = 0;
for (unsigned i = 0; i < c.size(); ++i) {
@ -144,7 +144,7 @@ namespace sat {
bool xor_finder::extract_xor(bool parity, clause& c, clause& c2) {
bool parity2 = false;
for (literal l : c2) {
if (!s.is_visited(l.var())) return false;
if (!s.m_visited.is_visited(l.var())) return false;
parity2 ^= !l.sign();
}
if (c2.size() == c.size() && parity2 != parity) {

8
src/sat/smt/pb_solver.cpp
View file

@ -2709,10 +2709,10 @@ namespace pb {
}
void solver::init_visited() { s().init_visited(); }
void solver::mark_visited(literal l) { s().mark_visited(l); }
void solver::mark_visited(bool_var v) { s().mark_visited(v); }
bool solver::is_visited(bool_var v) const { return s().is_visited(v); }
bool solver::is_visited(literal l) const { return s().is_visited(l); }
void solver::mark_visited(literal l) { s().m_visited.mark_visited(l); }
void solver::mark_visited(bool_var v) { s().m_visited.mark_visited(v); }
bool solver::is_visited(bool_var v) const { return s().m_visited.is_visited(v); }
bool solver::is_visited(literal l) const { return s().m_visited.is_visited(l); }
void solver::cleanup_clauses() {
if (m_clause_removed) {

39
src/util/visit_helper.h Normal file
View file

@ -0,0 +1,39 @@
#pragma once
#include "sat_literal.h"
class visit_helper {
unsigned_vector m_visited;
unsigned m_visited_begin = 0;
unsigned m_visited_end = 0;
void init_ts(unsigned n, unsigned lim = 1) {
SASSERT(lim > 0);
if (m_visited_end >= m_visited_end + lim) { // overflow
m_visited_begin = 0;
m_visited_end = lim;
m_visited.reset();
}
else {
m_visited_begin = m_visited_end;
m_visited_end = m_visited_end + lim;
}
while (m_visited.size() < n)
m_visited.push_back(0);
}
public:
void init_visited(unsigned num_vars, unsigned lim = 1) {
init_ts(2 * num_vars, lim);
}
void mark_visited(sat::literal l) { m_visited[l.index()] = m_visited_begin + 1; }
void mark_visited(sat::bool_var v) { mark_visited(sat::literal(v, false)); }
void inc_visited(sat::literal l) {
m_visited[l.index()] = std::min(m_visited_end, std::max(m_visited_begin, m_visited[l.index()]) + 1);
}
void inc_visited(sat::bool_var v) { inc_visited(sat::literal(v, false)); }
bool is_visited(sat::bool_var v) const { return is_visited(sat::literal(v, false)); }
bool is_visited(sat::literal l) const { return m_visited[l.index()] > m_visited_begin; }
unsigned num_visited(unsigned i) { return std::max(m_visited_begin, m_visited[i]) - m_visited_begin; }
};