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/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds, 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.
* ****************************************************************************
*
* Implementation of a utility for updating proof nodes.
*/
#include "expr/proof_node_updater.h"
#include "expr/lazy_proof.h"
#include "expr/proof_ensure_closed.h"
#include "expr/proof_node_algorithm.h"
#include "expr/proof_node_manager.h"
namespace cvc5 {
ProofNodeUpdaterCallback::ProofNodeUpdaterCallback() {}
ProofNodeUpdaterCallback::~ProofNodeUpdaterCallback() {}
bool ProofNodeUpdaterCallback::update(Node res,
PfRule id,
const std::vector<Node>& children,
const std::vector<Node>& args,
CDProof* cdp,
bool& continueUpdate)
{
return false;
}
ProofNodeUpdater::ProofNodeUpdater(ProofNodeManager* pnm,
ProofNodeUpdaterCallback& cb,
bool mergeSubproofs,
bool autoSym)
: d_pnm(pnm),
d_cb(cb),
d_debugFreeAssumps(false),
d_mergeSubproofs(mergeSubproofs),
d_autoSym(autoSym)
{
}
void ProofNodeUpdater::process(std::shared_ptr<ProofNode> pf)
{
if (d_debugFreeAssumps)
{
if (Trace.isOn("pfnu-debug"))
{
Trace("pfnu-debug2") << "Initial proof: " << *pf.get() << std::endl;
Trace("pfnu-debug") << "ProofNodeUpdater::process" << std::endl;
Trace("pfnu-debug") << "Expected free assumptions: " << std::endl;
for (const Node& fa : d_freeAssumps)
{
Trace("pfnu-debug") << "- " << fa << std::endl;
}
std::vector<Node> assump;
expr::getFreeAssumptions(pf.get(), assump);
Trace("pfnu-debug") << "Current free assumptions: " << std::endl;
for (const Node& fa : assump)
{
Trace("pfnu-debug") << "- " << fa << std::endl;
}
}
}
std::vector<std::shared_ptr<ProofNode>> traversing;
processInternal(pf, d_freeAssumps, traversing);
}
void ProofNodeUpdater::processInternal(
std::shared_ptr<ProofNode> pf,
const std::vector<Node>& fa,
std::vector<std::shared_ptr<ProofNode>>& traversing)
{
Trace("pf-process") << "ProofNodeUpdater::process" << std::endl;
std::unordered_map<std::shared_ptr<ProofNode>, bool> visited;
std::unordered_map<std::shared_ptr<ProofNode>, bool>::iterator it;
std::vector<std::shared_ptr<ProofNode>> visit;
std::shared_ptr<ProofNode> cur;
visit.push_back(pf);
std::map<Node, std::shared_ptr<ProofNode>>::iterator itc;
// A cache from formulas to proof nodes that are in the current scope.
// Notice that we make a fresh recursive call to process if the current
// rule is SCOPE below.
std::map<Node, std::shared_ptr<ProofNode>> resCache;
Node res;
do
{
cur = visit.back();
visit.pop_back();
it = visited.find(cur);
res = cur->getResult();
if (it == visited.end())
{
if (d_mergeSubproofs)
{
itc = resCache.find(res);
if (itc != resCache.end())
{
// already have a proof, merge it into this one
visited[cur] = true;
d_pnm->updateNode(cur.get(), itc->second.get());
continue;
}
}
// run update to a fixed point
bool continueUpdate = true;
while (runUpdate(cur, fa, continueUpdate) && continueUpdate)
{
Trace("pf-process-debug") << "...updated proof." << std::endl;
}
visited[cur] = !continueUpdate;
if (!continueUpdate)
{
// no further changes should be made to cur according to the callback
Trace("pf-process-debug")
<< "...marked to not continue update." << std::endl;
runFinalize(cur, fa, resCache);
continue;
}
traversing.push_back(cur);
visit.push_back(cur);
// If we are not the top-level proof, we were a scope, or became a scope
// after updating, we do a separate recursive call to this method. This
// allows us to properly track the assumptions in scope, which is
// important for example to merge or to determine updates based on free
// assumptions.
if (cur->getRule() == PfRule::SCOPE && cur != pf)
{
std::vector<Node> nfa;
nfa.insert(nfa.end(), fa.begin(), fa.end());
const std::vector<Node>& args = cur->getArguments();
nfa.insert(nfa.end(), args.begin(), args.end());
Trace("pfnu-debug2") << "Process new scope with " << args << std::endl;
// Process in new call separately
processInternal(cur, nfa, traversing);
continue;
}
const std::vector<std::shared_ptr<ProofNode>>& ccp = cur->getChildren();
// now, process children
for (const std::shared_ptr<ProofNode>& cp : ccp)
{
if (std::find(traversing.begin(), traversing.end(), cp)
!= traversing.end())
{
Unhandled()
<< "ProofNodeUpdater::processInternal: cyclic proof! (use "
"--proof-eager-checking)"
<< std::endl;
}
visit.push_back(cp);
}
}
else if (!it->second)
{
Assert(!traversing.empty());
traversing.pop_back();
visited[cur] = true;
// finalize the node
runFinalize(cur, fa, resCache);
}
} while (!visit.empty());
Trace("pf-process") << "ProofNodeUpdater::process: finished" << std::endl;
}
bool ProofNodeUpdater::runUpdate(std::shared_ptr<ProofNode> cur,
const std::vector<Node>& fa,
bool& continueUpdate)
{
// should it be updated?
if (!d_cb.shouldUpdate(cur, fa, continueUpdate))
{
return false;
}
PfRule id = cur->getRule();
// use CDProof to open a scope for which the callback updates
CDProof cpf(d_pnm, nullptr, "ProofNodeUpdater::CDProof", d_autoSym);
const std::vector<std::shared_ptr<ProofNode>>& cc = cur->getChildren();
std::vector<Node> ccn;
for (const std::shared_ptr<ProofNode>& cp : cc)
{
Node cpres = cp->getResult();
ccn.push_back(cpres);
// store in the proof
cpf.addProof(cp);
}
Node res = cur->getResult();
Trace("pf-process-debug")
<< "Updating (" << cur->getRule() << "): " << res << std::endl;
// only if the callback updated the node
if (d_cb.update(res, id, ccn, cur->getArguments(), &cpf, continueUpdate))
{
std::shared_ptr<ProofNode> npn = cpf.getProofFor(res);
std::vector<Node> fullFa;
if (d_debugFreeAssumps)
{
expr::getFreeAssumptions(cur.get(), fullFa);
Trace("pfnu-debug") << "Original proof : " << *cur << std::endl;
}
// then, update the original proof node based on this one
Trace("pf-process-debug") << "Update node..." << std::endl;
d_pnm->updateNode(cur.get(), npn.get());
Trace("pf-process-debug") << "...update node finished." << std::endl;
if (d_debugFreeAssumps)
{
fullFa.insert(fullFa.end(), fa.begin(), fa.end());
// We have that npn is a node we occurring the final updated version of
// the proof. We can now debug based on the expected set of free
// assumptions.
Trace("pfnu-debug") << "Ensure update closed..." << std::endl;
pfnEnsureClosedWrt(
npn.get(), fullFa, "pfnu-debug", "ProofNodeUpdater:postupdate");
}
Trace("pf-process-debug") << "..finished" << std::endl;
return true;
}
Trace("pf-process-debug") << "..finished" << std::endl;
return false;
}
void ProofNodeUpdater::runFinalize(
std::shared_ptr<ProofNode> cur,
const std::vector<Node>& fa,
std::map<Node, std::shared_ptr<ProofNode>>& resCache)
{
if (d_mergeSubproofs)
{
Node res = cur->getResult();
// cache result if we are merging subproofs
resCache[res] = cur;
}
if (d_debugFreeAssumps)
{
// We have that npn is a node we occurring the final updated version of
// the proof. We can now debug based on the expected set of free
// assumptions.
Trace("pfnu-debug") << "Ensure update closed..." << std::endl;
pfnEnsureClosedWrt(
cur.get(), fa, "pfnu-debug", "ProofNodeUpdater:finalize");
}
}
void ProofNodeUpdater::setDebugFreeAssumptions(
const std::vector<Node>& freeAssumps)
{
d_freeAssumps.clear();
d_freeAssumps.insert(
d_freeAssumps.end(), freeAssumps.begin(), freeAssumps.end());
d_debugFreeAssumps = true;
}
} // namespace cvc5
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