path: root/libsolidity/formal/SMTLib2Interface.cpp

/*
    This file is part of solidity.

    solidity is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    solidity is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with solidity.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <libsolidity/formal/SMTLib2Interface.h>

#include <libsolidity/interface/Exceptions.h>
#include <libsolidity/interface/ReadFile.h>

#include <boost/algorithm/string/predicate.hpp>
#include <boost/algorithm/string/join.hpp>
#include <boost/filesystem/operations.hpp>

#include <cstdio>
#include <fstream>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <array>

using namespace std;
using namespace dev;
using namespace dev::solidity;
using namespace dev::solidity::smt;

SMTLib2Interface::SMTLib2Interface(ReadCallback::Callback const& _queryCallback):
    m_queryCallback(_queryCallback)
{
    reset();
}

void SMTLib2Interface::reset()
{
    m_accumulatedOutput.clear();
    m_accumulatedOutput.emplace_back();
    write("(set-option :produce-models true)");
    write("(set-logic QF_UFLIA)");
}

void SMTLib2Interface::push()
{
    m_accumulatedOutput.emplace_back();
}

void SMTLib2Interface::pop()
{
    solAssert(!m_accumulatedOutput.empty(), "");
    m_accumulatedOutput.pop_back();
}

Expression SMTLib2Interface::newFunction(string _name, Sort _domain, Sort _codomain)
{
    write(
        "(declare-fun |" +
        _name +
        "| (" +
        (_domain == Sort::Int ? "Int" : "Bool") +
        ") " +
        (_codomain == Sort::Int ? "Int" : "Bool") +
        ")"
    );
    return SolverInterface::newFunction(move(_name), _domain, _codomain);
}

Expression SMTLib2Interface::newInteger(string _name)
{
    write("(declare-const |" + _name + "| Int)");
    return SolverInterface::newInteger(move(_name));
}

Expression SMTLib2Interface::newBool(string _name)
{
    write("(declare-const |" + _name + "| Bool)");
    return SolverInterface::newBool(std::move(_name));
}

void SMTLib2Interface::addAssertion(Expression const& _expr)
{
    write("(assert " + toSExpr(_expr) + ")");
}

pair<CheckResult, vector<string>> SMTLib2Interface::check(vector<Expression> const& _expressionsToEvaluate)
{
    string response = querySolver(
        boost::algorithm::join(m_accumulatedOutput, "\n") +
        checkSatAndGetValuesCommand(_expressionsToEvaluate)
    );

    CheckResult result;
    // TODO proper parsing
    if (boost::starts_with(response, "sat\n"))
        result = CheckResult::SATISFIABLE;
    else if (boost::starts_with(response, "unsat\n"))
        result = CheckResult::UNSATISFIABLE;
    else if (boost::starts_with(response, "unknown\n"))
        result = CheckResult::UNKNOWN;
    else
        result = CheckResult::ERROR;

    vector<string> values;
    if (result != CheckResult::UNSATISFIABLE && result != CheckResult::ERROR)
        values = parseValues(find(response.cbegin(), response.cend(), '\n'), response.cend());
    return make_pair(result, values);
}

string SMTLib2Interface::toSExpr(Expression const& _expr)
{
    if (_expr.arguments.empty())
        return _expr.name;
    std::string sexpr = "(" + _expr.name;
    for (auto const& arg: _expr.arguments)
        sexpr += " " + toSExpr(arg);
    sexpr += ")";
    return sexpr;
}

void SMTLib2Interface::write(string _data)
{
    solAssert(!m_accumulatedOutput.empty(), "");
    m_accumulatedOutput.back() += move(_data) + "\n";
}

string SMTLib2Interface::checkSatAndGetValuesCommand(vector<Expression> const& _expressionsToEvaluate)
{
    string command;
    if (_expressionsToEvaluate.empty())
        command = "(check-sat)\n";
    else
    {
        // TODO make sure these are unique
        for (size_t i = 0; i < _expressionsToEvaluate.size(); i++)
        {
            auto const& e = _expressionsToEvaluate.at(i);
            // TODO they don't have to be ints...
            command += "(declare-const |EVALEXPR_" + to_string(i) + "| Int)\n";
            command += "(assert (= |EVALEXPR_" + to_string(i) + "| " + toSExpr(e) + "))\n";
        }
        command += "(check-sat)\n";
        command += "(get-value (";
        for (size_t i = 0; i < _expressionsToEvaluate.size(); i++)
            command += "|EVALEXPR_" + to_string(i) + "| ";
        command += "))\n";
    }

    return command;
}

vector<string> SMTLib2Interface::parseValues(string::const_iterator _start, string::const_iterator _end)
{
    vector<string> values;
    while (_start < _end)
    {
        auto valStart = find(_start, _end, ' ');
        if (valStart < _end)
            ++valStart;
        auto valEnd = find(valStart, _end, ')');
        values.emplace_back(valStart, valEnd);
        _start = find(valEnd, _end, '(');
    }

    return values;
}

string SMTLib2Interface::querySolver(string const& _input)
{
    if (!m_queryCallback)
        BOOST_THROW_EXCEPTION(SolverError() << errinfo_comment("No SMT solver available."));

    ReadCallback::Result queryResult = m_queryCallback(_input);
    if (!queryResult.success)
        BOOST_THROW_EXCEPTION(SolverError() << errinfo_comment(queryResult.responseOrErrorMessage));
    return queryResult.responseOrErrorMessage;
}