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/********************* */
/*! \file sep_skolem_emp.cpp
** \verbatim
** Top contributors (to current version):
** Yoni Zohar, Andrew Reynolds, Gereon Kremer
** This file is part of the CVC4 project.
** Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
** in the top-level source directory and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief The sep-pre-skolem-emp preprocessing pass
**
**/
#include "preprocessing/passes/sep_skolem_emp.h"
#include <string>
#include <unordered_map>
#include <vector>
#include "expr/node.h"
#include "preprocessing/assertion_pipeline.h"
#include "theory/quantifiers/quant_util.h"
#include "theory/rewriter.h"
#include "theory/theory.h"
namespace cvc5 {
namespace preprocessing {
namespace passes {
using namespace std;
using namespace cvc5::theory;
namespace {
Node preSkolemEmp(Node n,
bool pol,
std::map<bool, std::map<Node, Node>>& visited)
{
std::map<Node, Node>::iterator it = visited[pol].find(n);
if (it == visited[pol].end())
{
Trace("sep-preprocess") << "Pre-skolem emp " << n << " with pol " << pol
<< std::endl;
Node ret = n;
if (n.getKind() == kind::SEP_EMP)
{
if (!pol)
{
TypeNode tnx = n[0].getType();
TypeNode tny = n[1].getType();
Node x = NodeManager::currentNM()->mkSkolem(
"ex", tnx, "skolem location for negated emp");
Node y = NodeManager::currentNM()->mkSkolem(
"ey", tny, "skolem data for negated emp");
return NodeManager::currentNM()
->mkNode(kind::SEP_STAR,
NodeManager::currentNM()->mkNode(kind::SEP_PTO, x, y),
NodeManager::currentNM()->mkConst(true))
.negate();
}
}
else if (n.getKind() != kind::FORALL && n.getNumChildren() > 0)
{
std::vector<Node> children;
bool childChanged = false;
if (n.getMetaKind() == kind::metakind::PARAMETERIZED)
{
children.push_back(n.getOperator());
}
for (unsigned i = 0; i < n.getNumChildren(); i++)
{
bool newPol, newHasPol;
QuantPhaseReq::getPolarity(n, i, true, pol, newHasPol, newPol);
Node nc = n[i];
if (newHasPol)
{
nc = preSkolemEmp(n[i], newPol, visited);
childChanged = childChanged || nc != n[i];
}
children.push_back(nc);
}
if (childChanged)
{
return NodeManager::currentNM()->mkNode(n.getKind(), children);
}
}
visited[pol][n] = ret;
return n;
}
else
{
return it->second;
}
}
} // namespace
SepSkolemEmp::SepSkolemEmp(PreprocessingPassContext* preprocContext)
: PreprocessingPass(preprocContext, "sep-skolem-emp"){};
PreprocessingPassResult SepSkolemEmp::applyInternal(
AssertionPipeline* assertionsToPreprocess)
{
std::map<bool, std::map<Node, Node>> visited;
for (unsigned i = 0; i < assertionsToPreprocess->size(); ++i)
{
Node prev = (*assertionsToPreprocess)[i];
bool pol = true;
Node next = preSkolemEmp(prev, pol, visited);
if (next != prev)
{
assertionsToPreprocess->replace(i, Rewriter::rewrite(next));
Trace("sep-preprocess") << "*** Preprocess sep " << prev << endl;
Trace("sep-preprocess") << " ...got " << (*assertionsToPreprocess)[i]
<< endl;
}
visited.clear();
}
return PreprocessingPassResult::NO_CONFLICT;
}
} // namespace passes
} // namespace preprocessing
} // namespace cvc5
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