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/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds, Andres Noetzli, 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.
* ****************************************************************************
*
* AssertionPipeline stores a list of assertions modified by
* preprocessing passes.
*/
#include "preprocessing/assertion_pipeline.h"
#include "expr/node_manager.h"
#include "options/smt_options.h"
#include "proof/lazy_proof.h"
#include "smt/preprocess_proof_generator.h"
#include "theory/builtin/proof_checker.h"
#include "theory/rewriter.h"
namespace cvc5 {
namespace preprocessing {
AssertionPipeline::AssertionPipeline()
: d_realAssertionsEnd(0),
d_storeSubstsInAsserts(false),
d_substsIndex(0),
d_assumptionsStart(0),
d_numAssumptions(0),
d_pppg(nullptr)
{
}
void AssertionPipeline::clear()
{
d_nodes.clear();
d_realAssertionsEnd = 0;
d_assumptionsStart = 0;
d_numAssumptions = 0;
}
void AssertionPipeline::push_back(Node n,
bool isAssumption,
bool isInput,
ProofGenerator* pgen)
{
d_nodes.push_back(n);
if (isAssumption)
{
Assert(pgen == nullptr);
if (d_numAssumptions == 0)
{
d_assumptionsStart = d_nodes.size() - 1;
}
// Currently, we assume that assumptions are all added one after another
// and that we store them in the same vector as the assertions. Once we
// split the assertions up into multiple vectors (see issue #2473), we will
// not have this limitation anymore.
Assert(d_assumptionsStart + d_numAssumptions == d_nodes.size() - 1);
d_numAssumptions++;
}
Trace("assert-pipeline") << "Assertions: ...new assertion " << n
<< ", isInput=" << isInput << std::endl;
if (isProofEnabled())
{
if (!isInput)
{
// notice this is always called, regardless of whether pgen is nullptr
d_pppg->notifyNewAssert(n, pgen);
}
else
{
Assert(pgen == nullptr);
// n is an input assertion, whose proof should be ASSUME.
d_pppg->notifyInput(n);
}
}
}
void AssertionPipeline::pushBackTrusted(theory::TrustNode trn)
{
Assert(trn.getKind() == theory::TrustNodeKind::LEMMA);
// push back what was proven
push_back(trn.getProven(), false, false, trn.getGenerator());
}
void AssertionPipeline::replace(size_t i, Node n, ProofGenerator* pgen)
{
if (n == d_nodes[i])
{
// no change, skip
return;
}
Trace("assert-pipeline") << "Assertions: Replace " << d_nodes[i] << " with "
<< n << std::endl;
if (isProofEnabled())
{
d_pppg->notifyPreprocessed(d_nodes[i], n, pgen);
}
d_nodes[i] = n;
}
void AssertionPipeline::replaceTrusted(size_t i, theory::TrustNode trn)
{
if (trn.isNull())
{
// null trust node denotes no change, nothing to do
return;
}
Assert(trn.getKind() == theory::TrustNodeKind::REWRITE);
Assert(trn.getProven()[0] == d_nodes[i]);
replace(i, trn.getNode(), trn.getGenerator());
}
void AssertionPipeline::setProofGenerator(smt::PreprocessProofGenerator* pppg)
{
d_pppg = pppg;
}
bool AssertionPipeline::isProofEnabled() const { return d_pppg != nullptr; }
void AssertionPipeline::enableStoreSubstsInAsserts()
{
d_storeSubstsInAsserts = true;
d_substsIndex = d_nodes.size();
d_nodes.push_back(NodeManager::currentNM()->mkConst<bool>(true));
}
void AssertionPipeline::disableStoreSubstsInAsserts()
{
d_storeSubstsInAsserts = false;
}
void AssertionPipeline::addSubstitutionNode(Node n, ProofGenerator* pg)
{
Assert(d_storeSubstsInAsserts);
Assert(n.getKind() == kind::EQUAL);
conjoin(d_substsIndex, n, pg);
}
void AssertionPipeline::conjoin(size_t i, Node n, ProofGenerator* pg)
{
NodeManager* nm = NodeManager::currentNM();
Node newConj = nm->mkNode(kind::AND, d_nodes[i], n);
Node newConjr = theory::Rewriter::rewrite(newConj);
Trace("assert-pipeline") << "Assertions: conjoin " << n << " to "
<< d_nodes[i] << std::endl;
Trace("assert-pipeline-debug") << "conjoin " << n << " to " << d_nodes[i]
<< ", got " << newConjr << std::endl;
if (newConjr == d_nodes[i])
{
// trivial, skip
return;
}
if (isProofEnabled())
{
if (newConjr == n)
{
// don't care about the previous proof and can simply plug in the
// proof from pg if the resulting assertion is the same as n.
d_pppg->notifyNewAssert(newConjr, pg);
}
else
{
// ---------- from pppg --------- from pg
// d_nodes[i] n
// -------------------------------- AND_INTRO
// d_nodes[i] ^ n
// -------------------------------- MACRO_SR_PRED_TRANSFORM
// rewrite( d_nodes[i] ^ n )
// allocate a fresh proof which will act as the proof generator
LazyCDProof* lcp = d_pppg->allocateHelperProof();
lcp->addLazyStep(n, pg, PfRule::PREPROCESS);
if (d_nodes[i].isConst() && d_nodes[i].getConst<bool>())
{
// skip the AND_INTRO if the previous d_nodes[i] was true
newConj = n;
}
else
{
lcp->addLazyStep(d_nodes[i], d_pppg);
lcp->addStep(newConj, PfRule::AND_INTRO, {d_nodes[i], n}, {});
}
if (newConjr != newConj)
{
lcp->addStep(
newConjr, PfRule::MACRO_SR_PRED_TRANSFORM, {newConj}, {newConjr});
}
// Notice we have constructed a proof of a new assertion, where d_pppg
// is referenced in the lazy proof above. If alternatively we had
// constructed a proof of d_nodes[i] = rewrite( d_nodes[i] ^ n ), we would
// have used notifyPreprocessed. However, it is simpler to make the
// above proof.
d_pppg->notifyNewAssert(newConjr, lcp);
}
}
d_nodes[i] = newConjr;
Assert(theory::Rewriter::rewrite(newConjr) == newConjr);
}
} // namespace preprocessing
} // namespace cvc5
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