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/******************************************************************************
* Top contributors (to current version):
* Mathias Preiner, Gereon Kremer, Haniel Barbosa
*
* This file is part of the cvc5 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.
* ****************************************************************************
*
* Bit-blast solver that sends bit-blast lemmas directly to the internal
* MiniSat.
*/
#include "theory/bv/bv_solver_bitblast_internal.h"
#include "proof/conv_proof_generator.h"
#include "theory/bv/theory_bv.h"
#include "theory/bv/theory_bv_utils.h"
#include "theory/theory_model.h"
namespace cvc5 {
namespace theory {
namespace bv {
/* -------------------------------------------------------------------------- */
namespace {
bool isBVAtom(TNode n)
{
return (n.getKind() == kind::EQUAL && n[0].getType().isBitVector())
|| n.getKind() == kind::BITVECTOR_ULT
|| n.getKind() == kind::BITVECTOR_ULE
|| n.getKind() == kind::BITVECTOR_SLT
|| n.getKind() == kind::BITVECTOR_SLE;
}
/* Traverse Boolean nodes and collect BV atoms. */
void collectBVAtoms(TNode n, std::unordered_set<Node>& atoms)
{
std::vector<TNode> visit;
std::unordered_set<TNode> visited;
visit.push_back(n);
do
{
TNode cur = visit.back();
visit.pop_back();
if (visited.find(cur) != visited.end() || !cur.getType().isBoolean())
continue;
visited.insert(cur);
if (isBVAtom(cur))
{
atoms.insert(cur);
continue;
}
visit.insert(visit.end(), cur.begin(), cur.end());
} while (!visit.empty());
}
} // namespace
BVSolverBitblastInternal::BVSolverBitblastInternal(
Env& env,
TheoryState* s,
TheoryInferenceManager& inferMgr,
ProofNodeManager* pnm)
: BVSolver(env, *s, inferMgr),
d_pnm(pnm),
d_bitblaster(new BBProof(s, pnm, false))
{
}
void BVSolverBitblastInternal::addBBLemma(TNode fact)
{
if (!d_bitblaster->hasBBAtom(fact))
{
d_bitblaster->bbAtom(fact);
}
NodeManager* nm = NodeManager::currentNM();
Node atom_bb = d_bitblaster->getStoredBBAtom(fact);
Node lemma = nm->mkNode(kind::EQUAL, fact, atom_bb);
if (d_pnm == nullptr)
{
d_im.lemma(lemma, InferenceId::BV_BITBLAST_INTERNAL_BITBLAST_LEMMA);
}
else
{
TrustNode tlem =
TrustNode::mkTrustLemma(lemma, d_bitblaster->getProofGenerator());
d_im.trustedLemma(tlem, InferenceId::BV_BITBLAST_INTERNAL_BITBLAST_LEMMA);
}
}
bool BVSolverBitblastInternal::preNotifyFact(
TNode atom, bool pol, TNode fact, bool isPrereg, bool isInternal)
{
if (fact.getKind() == kind::NOT)
{
fact = fact[0];
}
if (isBVAtom(fact))
{
addBBLemma(fact);
}
else if (fact.getKind() == kind::BITVECTOR_EAGER_ATOM)
{
TNode n = fact[0];
NodeManager* nm = NodeManager::currentNM();
Node lemma = nm->mkNode(kind::EQUAL, fact, n);
if (d_pnm == nullptr)
{
d_im.lemma(lemma, InferenceId::BV_BITBLAST_INTERNAL_EAGER_LEMMA);
}
else
{
d_bitblaster->getProofGenerator()->addRewriteStep(
fact, n, PfRule::BV_EAGER_ATOM, {}, {fact});
TrustNode tlem =
TrustNode::mkTrustLemma(lemma, d_bitblaster->getProofGenerator());
d_im.trustedLemma(tlem, InferenceId::BV_BITBLAST_INTERNAL_EAGER_LEMMA);
}
std::unordered_set<Node> bv_atoms;
collectBVAtoms(n, bv_atoms);
for (const Node& nn : bv_atoms)
{
addBBLemma(nn);
}
}
return false; // Return false to enable equality engine reasoning in Theory.
}
TrustNode BVSolverBitblastInternal::explain(TNode n)
{
Debug("bv-bitblast-internal") << "explain called on " << n << std::endl;
return d_im.explainLit(n);
}
bool BVSolverBitblastInternal::collectModelValues(TheoryModel* m,
const std::set<Node>& termSet)
{
return d_bitblaster->collectModelValues(m, termSet);
}
Node BVSolverBitblastInternal::getValue(TNode node, bool initialize)
{
if (node.isConst())
{
return node;
}
if (!d_bitblaster->hasBBTerm(node))
{
return initialize ? utils::mkConst(utils::getSize(node), 0u) : Node();
}
Valuation& val = d_state.getValuation();
std::vector<Node> bits;
d_bitblaster->getBBTerm(node, bits);
Integer value(0), one(1), zero(0), bit;
for (size_t i = 0, size = bits.size(), j = size - 1; i < size; ++i, --j)
{
bool satValue;
if (val.hasSatValue(bits[j], satValue))
{
bit = satValue ? one : zero;
}
else
{
if (!initialize) return Node();
bit = zero;
}
value = value * 2 + bit;
}
return utils::mkConst(bits.size(), value);
}
BVProofRuleChecker* BVSolverBitblastInternal::getProofChecker()
{
return &d_checker;
}
} // namespace bv
} // namespace theory
} // namespace cvc5
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