spot/spot/twaalgos/ltl2taa.cc
Alexandre Duret-Lutz c63521d67a work around potential null dereference warning
* spot/twaalgos/ltl2taa.cc: Here.
* NEWS: Mention the issue.
2019-03-17 17:19:10 +01:00

404 lines
13 KiB
C++

// -*- coding: utf-8 -*-
// Copyright (C) 2009-2010, 2012-2016, 2018-2019 Laboratoire de
// Recherche et Développement de l'Epita (LRDE).
//
// This file is part of Spot, a model checking library.
//
// Spot is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// Spot is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "config.h"
#include <utility>
#include <algorithm>
#include <cassert>
#include <spot/tl/unabbrev.hh>
#include <spot/tl/nenoform.hh>
#include <spot/tl/contain.hh>
#include <spot/twaalgos/ltl2taa.hh>
namespace spot
{
namespace
{
/// \brief Recursively translate a formula into a TAA.
class ltl2taa_visitor final
{
public:
ltl2taa_visitor(const taa_tgba_formula_ptr& res,
language_containment_checker* lcc,
bool refined = false, bool negated = false)
: res_(res), refined_(refined), negated_(negated),
lcc_(lcc), init_(), succ_()
{
}
taa_tgba_formula_ptr&
result()
{
res_->set_init_state(init_);
return res_;
}
void
visit(formula f)
{
init_ = f;
switch (f.kind())
{
case op::ff:
return;
case op::tt:
{
std::vector<formula> empty;
res_->create_transition(init_, empty);
succ_state ss = { empty, f, empty };
succ_.emplace_back(ss);
return;
}
case op::eword:
SPOT_UNIMPLEMENTED();
case op::ap:
{
res_->register_ap(f);
if (negated_)
f = formula::Not(f);
init_ = f;
std::vector<formula> empty;
taa_tgba::transition* t = res_->create_transition(init_, empty);
res_->add_condition(t, f);
succ_state ss = { empty, f, empty };
succ_.emplace_back(ss);
return;
}
case op::X:
{
ltl2taa_visitor v = recurse(f[0]);
std::vector<formula> dst;
std::vector<formula> a;
if (v.succ_.empty()) // Handle X(0)
return;
dst.emplace_back(v.init_);
res_->create_transition(init_, dst);
succ_state ss = { dst, formula::tt(), a };
succ_.emplace_back(ss);
return;
}
case op::F:
case op::G:
SPOT_UNIMPLEMENTED(); // TBD
return;
case op::Not:
{
negated_ = true;
ltl2taa_visitor v = recurse(f[0]);
// Done in recurse
succ_ = v.succ_;
return;
}
case op::Closure:
case op::NegClosure:
case op::NegClosureMarked:
case op::Star:
case op::FStar:
case op::Xor:
case op::Implies:
case op::Equiv:
case op::UConcat:
case op::EConcat:
case op::EConcatMarked:
case op::Concat:
case op::Fusion:
case op::AndNLM:
case op::AndRat:
case op::OrRat:
SPOT_UNIMPLEMENTED();
case op::U:
case op::W:
case op::R:
case op::M:
visit_binop(f);
return;
case op::And:
case op::Or:
visit_multop(f);
return;
}
}
void
visit_binop(formula f)
{
ltl2taa_visitor v1 = recurse(f[0]);
ltl2taa_visitor v2 = recurse(f[1]);
std::vector<succ_state>::iterator i1;
std::vector<succ_state>::iterator i2;
taa_tgba::transition* t = nullptr;
bool contained = false;
bool strong = false;
switch (f.kind())
{
case op::U:
strong = true;
SPOT_FALLTHROUGH;
case op::W:
if (refined_)
contained = lcc_->contained(f[0], f[1]);
for (i1 = v1.succ_.begin(); i1 != v1.succ_.end(); ++i1)
{
// Refined rule
if (refined_ && contained)
i1->Q.erase
(remove(i1->Q.begin(), i1->Q.end(), v1.init_), i1->Q.end());
i1->Q.emplace_back(init_); // Add the initial state
if (strong)
i1->acc.emplace_back(f[1]);
t = res_->create_transition(init_, i1->Q);
res_->add_condition(t, i1->condition);
if (strong)
res_->add_acceptance_condition(t, f[1]);
else
for (unsigned i = 0; i < i1->acc.size(); ++i)
res_->add_acceptance_condition(t, i1->acc[i]);
succ_.emplace_back(*i1);
}
for (i2 = v2.succ_.begin(); i2 != v2.succ_.end(); ++i2)
{
t = res_->create_transition(init_, i2->Q);
res_->add_condition(t, i2->condition);
succ_.emplace_back(*i2);
}
return;
case op::M: // Strong Release
strong = true;
SPOT_FALLTHROUGH;
case op::R: // Weak Release
if (refined_)
contained = lcc_->contained(f[0], f[1]);
for (i2 = v2.succ_.begin(); i2 != v2.succ_.end(); ++i2)
{
for (i1 = v1.succ_.begin(); i1 != v1.succ_.end(); ++i1)
{
std::vector<formula> u; // Union
std::vector<formula> a; // Acceptance conditions
std::copy(i1->Q.begin(), i1->Q.end(), ii(u, u.end()));
formula f = i1->condition; // Refined rule
if (!refined_ || !contained)
{
std::copy(i2->Q.begin(), i2->Q.end(), ii(u, u.end()));
f = formula::And({f, i2->condition});
}
t = res_->create_transition(init_, u);
res_->add_condition(t, f);
succ_state ss = { u, f, a };
succ_.emplace_back(ss);
}
if (refined_) // Refined rule
i2->Q.erase
(remove(i2->Q.begin(), i2->Q.end(), v2.init_), i2->Q.end());
i2->Q.emplace_back(init_); // Add the initial state
t = res_->create_transition(init_, i2->Q);
res_->add_condition(t, i2->condition);
if (strong)
{
i2->acc.emplace_back(f[0]);
res_->add_acceptance_condition(t, f[0]);
}
else if (refined_)
for (unsigned i = 0; i < i2->acc.size(); ++i)
res_->add_acceptance_condition(t, i2->acc[i]);
succ_.emplace_back(*i2);
}
return;
default:
SPOT_UNIMPLEMENTED();
}
SPOT_UNREACHABLE();
}
void
visit_multop(formula f)
{
bool ok = true;
std::vector<ltl2taa_visitor> vs;
for (unsigned n = 0, s = f.size(); n < s; ++n)
{
vs.emplace_back(recurse(f[n]));
if (vs[n].succ_.empty()) // Handle 0
ok = false;
}
taa_tgba::transition* t = nullptr;
switch (f.kind())
{
case op::And:
{
if (!ok)
return;
std::vector<succ_state> p = all_n_tuples(vs);
for (unsigned n = 0; n < p.size(); ++n)
{
if (refined_)
{
std::vector<formula> v; // All sub initial states.
sort(p[n].Q.begin(), p[n].Q.end());
for (unsigned m = 0; m < f.size(); ++m)
{
if (!binary_search(p[n].Q.begin(), p[n].Q.end(),
vs[m].init_))
break;
v.emplace_back(vs[m].init_);
}
if (v.size() == f.size())
{
std::vector<formula> Q;
sort(v.begin(), v.end());
for (unsigned m = 0; m < p[n].Q.size(); ++m)
if (!binary_search(v.begin(), v.end(), p[n].Q[m]))
Q.emplace_back(p[n].Q[m]);
Q.emplace_back(init_);
t = res_->create_transition(init_, Q);
res_->add_condition(t, p[n].condition);
for (unsigned i = 0; i < p[n].acc.size(); ++i)
res_->add_acceptance_condition(t, p[n].acc[i]);
succ_.emplace_back(p[n]);
continue;
}
}
t = res_->create_transition(init_, p[n].Q);
res_->add_condition(t, p[n].condition);
succ_.emplace_back(p[n]);
}
return;
}
case op::Or:
for (unsigned n = 0, s = f.size(); n < s; ++n)
for (auto i: vs[n].succ_)
{
t = res_->create_transition(init_, i.Q);
res_->add_condition(t, i.condition);
succ_.emplace_back(i);
}
return;
default:
SPOT_UNIMPLEMENTED();
}
SPOT_UNREACHABLE();
}
ltl2taa_visitor
recurse(formula f)
{
ltl2taa_visitor v(res_, lcc_, refined_, negated_);
v.visit(f);
return v;
}
private:
taa_tgba_formula_ptr res_;
bool refined_;
bool negated_;
language_containment_checker* lcc_;
typedef std::insert_iterator<std::vector<formula>> ii;
struct succ_state
{
std::vector<formula> Q; // States
formula condition;
std::vector<formula> acc;
};
formula init_;
std::vector<succ_state> succ_;
public:
std::vector<succ_state>
all_n_tuples(const std::vector<ltl2taa_visitor>& vs)
{
std::vector<succ_state> product;
std::vector<int> pos(vs.size());
for (unsigned i = 0; i < vs.size(); ++i)
pos[i] = vs[i].succ_.size();
// g++ (Debian 8.3.0-3) 8.3.0 in --coverage mode,
// reports a "potential null pointer dereference" on the next
// line without this assert...
assert(pos.size() > 0);
while (pos[0] != 0)
{
std::vector<formula> u; // Union
std::vector<formula> a; // Acceptance conditions
formula f = formula::tt();
for (unsigned i = 0; i < vs.size(); ++i)
{
if (vs[i].succ_.empty())
continue;
const succ_state& ss(vs[i].succ_[pos[i] - 1]);
std::copy(ss.Q.begin(), ss.Q.end(), ii(u, u.end()));
f = formula::And({ss.condition, f});
for (unsigned i = 0; i < ss.acc.size(); ++i)
{
formula g = ss.acc[i];
a.emplace_back(g);
}
}
succ_state ss = { u, f, a };
product.emplace_back(ss);
for (int i = vs.size() - 1; i >= 0; --i)
{
if (vs[i].succ_.empty())
continue;
if (pos[i] > 1 || (i == 0 && pos[0] == 1))
{
--pos[i];
break;
}
else
pos[i] = vs[i].succ_.size();
}
}
return product;
}
};
} // anonymous
taa_tgba_formula_ptr
ltl_to_taa(formula f,
const bdd_dict_ptr& dict, bool refined_rules)
{
// TODO: implement translation of F and G
auto f2 = negative_normal_form(unabbreviate(f, "^ieFG"));
auto res = make_taa_tgba_formula(dict);
language_containment_checker* lcc =
new language_containment_checker(make_bdd_dict(),
false, false, false, false);
ltl2taa_visitor v(res, lcc, refined_rules);
v.visit(f2);
auto taa = v.result();
delete lcc;
taa->acc().set_generalized_buchi();
return taa;
}
}