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/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds
*
* 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.
* ****************************************************************************
*
* Class for verifying queries for synthesis solutions
*/
#include "theory/quantifiers/sygus/synth_verify.h"
#include "expr/node_algorithm.h"
#include "options/base_options.h"
#include "options/quantifiers_options.h"
#include "smt/smt_engine_scope.h"
#include "smt/smt_statistics_registry.h"
#include "theory/quantifiers/first_order_model.h"
#include "theory/quantifiers/sygus/term_database_sygus.h"
#include "theory/rewriter.h"
#include "theory/smt_engine_subsolver.h"
using namespace cvc5::kind;
using namespace std;
namespace cvc5 {
namespace theory {
namespace quantifiers {
SynthVerify::SynthVerify(TermDbSygus* tds) : d_tds(tds)
{
// determine the options to use for the verification subsolvers we spawn
// we start with the options of the current SmtEngine
SmtEngine* smtCurr = smt::currentSmtEngine();
d_subOptions.copyValues(smtCurr->getOptions());
// limit the number of instantiation rounds on subcalls
d_subOptions.quantifiers.instMaxRounds =
d_subOptions.quantifiers.sygusVerifyInstMaxRounds;
// Disable sygus on the subsolver. This is particularly important since it
// ensures that recursive function definitions have the standard ownership
// instead of being claimed by sygus in the subsolver.
d_subOptions.base.inputLanguage = language::input::LANG_SMTLIB_V2_6;
d_subOptions.quantifiers.sygus = false;
}
SynthVerify::~SynthVerify() {}
Result SynthVerify::verify(Node query,
const std::vector<Node>& vars,
std::vector<Node>& mvs)
{
NodeManager* nm = NodeManager::currentNM();
// simplify the lemma based on the term database sygus utility
query = d_tds->rewriteNode(query);
// eagerly unfold applications of evaluation function
Trace("cegqi-debug") << "pre-unfold counterexample : " << query << std::endl;
if (query.isConst())
{
if (!query.getConst<bool>())
{
return Result(Result::UNSAT);
}
// sat, but we need to get arbtirary model values below
}
else
{
// if non-constant, we may need to add recursive function definitions
FunDefEvaluator* feval = d_tds->getFunDefEvaluator();
const std::vector<Node>& fdefs = feval->getDefinitions();
if (!fdefs.empty())
{
// Get the relevant definitions based on the symbols in the query.
// Notice in some cases, this may have the effect of making the subcall
// involve no recursive function definitions at all, in which case the
// subcall to verification may be decidable, in which case the call
// below is guaranteed to generate a new counterexample point.
std::unordered_set<Node> syms;
expr::getSymbols(query, syms);
std::vector<Node> qconj;
qconj.push_back(query);
for (const Node& f : syms)
{
Node q = feval->getDefinitionFor(f);
if (!q.isNull())
{
qconj.push_back(q);
}
}
query = nm->mkAnd(qconj);
Trace("cegqi-debug") << "query is " << query << std::endl;
}
}
Trace("sygus-engine") << " *** Verify with subcall..." << std::endl;
Result r = checkWithSubsolver(query, vars, mvs, &d_subOptions);
Trace("sygus-engine") << " ...got " << r << std::endl;
if (r.asSatisfiabilityResult().isSat() == Result::SAT)
{
if (Trace.isOn("sygus-engine"))
{
Trace("sygus-engine") << " * Verification lemma failed for:\n ";
for (unsigned i = 0, size = vars.size(); i < size; i++)
{
Trace("sygus-engine") << vars[i] << " -> " << mvs[i] << " ";
}
Trace("sygus-engine") << std::endl;
}
if (Configuration::isAssertionBuild())
{
// the values for the query should be a complete model
Node squery =
query.substitute(vars.begin(), vars.end(), mvs.begin(), mvs.end());
Trace("cegqi-debug") << "...squery : " << squery << std::endl;
squery = Rewriter::rewrite(squery);
Trace("cegqi-debug") << "...rewrites to : " << squery << std::endl;
Assert(options::sygusRecFun()
|| (squery.isConst() && squery.getConst<bool>()));
}
}
return r;
}
} // namespace quantifiers
} // namespace theory
} // namespace cvc5
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