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/********************* */
/*! \file preprocess_proof_generator.cpp
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds
** This file is part of the CVC4 project.
** Copyright (c) 2009-2020 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 implementation of the module for proofs for preprocessing in an
** SMT engine.
**/
#include "smt/preprocess_proof_generator.h"
#include "expr/proof.h"
#include "theory/rewriter.h"
namespace CVC4 {
namespace smt {
PreprocessProofGenerator::PreprocessProofGenerator(ProofNodeManager* pnm)
: d_pnm(pnm)
{
}
void PreprocessProofGenerator::notifyNewAssert(Node n, ProofGenerator* pg)
{
Trace("smt-proof-pp-debug") << "- notifyNewAssert: " << n << std::endl;
d_src[n] = theory::TrustNode::mkTrustLemma(n, pg);
}
void PreprocessProofGenerator::notifyPreprocessed(Node n,
Node np,
ProofGenerator* pg)
{
// only keep if indeed it rewrote
if (n != np)
{
Trace("smt-proof-pp-debug")
<< "- notifyPreprocessed: " << n << "..." << np << std::endl;
d_src[np] = theory::TrustNode::mkTrustRewrite(n, np, pg);
}
}
std::shared_ptr<ProofNode> PreprocessProofGenerator::getProofFor(Node f)
{
std::map<Node, theory::TrustNode>::iterator it = d_src.find(f);
if (it == d_src.end())
{
// could be an assumption, return nullptr
return nullptr;
}
// make CDProof to construct the proof below
CDProof cdp(d_pnm);
Node curr = f;
std::vector<Node> transChildren;
bool success;
do
{
success = false;
if (it != d_src.end())
{
Assert(it->second.getNode() == curr);
bool proofStepProcessed = false;
std::shared_ptr<ProofNode> pfr = it->second.toProofNode();
if (pfr != nullptr)
{
Assert(pfr->getResult() == it->second.getProven());
cdp.addProof(pfr);
proofStepProcessed = true;
}
if (it->second.getKind() == theory::TrustNodeKind::REWRITE)
{
Node eq = it->second.getProven();
Assert(eq.getKind() == kind::EQUAL);
if (!proofStepProcessed)
{
// maybe its just a simple rewrite?
if (eq[1] == theory::Rewriter::rewrite(eq[0]))
{
cdp.addStep(eq, PfRule::REWRITE, {}, {eq[0]});
proofStepProcessed = true;
}
}
transChildren.push_back(eq);
// continue with source
curr = eq[0];
success = true;
// find the next node
it = d_src.find(curr);
}
else
{
Assert(it->second.getKind() == theory::TrustNodeKind::LEMMA);
}
if (!proofStepProcessed)
{
// add trusted step
Node proven = it->second.getProven();
cdp.addStep(proven, PfRule::PREPROCESS, {}, {proven});
}
}
} while (success);
Assert(curr != f);
// prove ( curr == f )
Node fullRewrite = curr.eqNode(f);
if (transChildren.size() >= 2)
{
cdp.addStep(fullRewrite, PfRule::TRANS, transChildren, {});
}
// prove f
cdp.addStep(f, PfRule::EQ_RESOLVE, {curr, fullRewrite}, {});
// overall, proof is:
// --------- from proof generator ---------- from proof generator
// F_1 = F_2 ... F_{n-1} = F_n
// ---? -------------------------------------------------- TRANS
// F_1 F_1 = F_n
// ---------------- EQ_RESOLVE
// F_n
// Note F_1 may have been given a proof if it was not an input assumption.
return cdp.getProofFor(f);
}
std::string PreprocessProofGenerator::identify() const
{
return "PreprocessProofGenerator";
}
} // namespace smt
} // namespace CVC4
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