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

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

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

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


//namespace
//{

//void createSubprocess(FILE*& _readPipe, FILE*& _writePipe)
//{
//  int pipe_in[2];   /* This is the pipe with wich we write to the child process. */
//  int pipe_out[2];  /* This is the pipe with wich we read from the child process. */

//  solAssert(!pipe(pipe_in) && !pipe(pipe_out), "");

//  /* Attempt to fork and check for errors */
//  pid_t pid = fork();
//  solAssert(pid != -1, "");

//  if (pid)
//  {
//      /* The parent has the non-zero PID. */
//      _readPipe = fdopen(pipe_out[0], "r");
//      _writePipe = fdopen(pipe_in[1], "w");
//      close(pipe_out[1]);
//      close(pipe_in[0]);
//  }
//  else
//  {
//      /* The child has the zero pid returned by fork*/
//      cout << "child" << endl;
//      solAssert(dup2(pipe_out[1], 1) != -1, "");
//      solAssert(dup2(pipe_in[0], 0) != -1, "");
//      solAssert(close(pipe_out[0]) == 0, "");
//      solAssert(close(pipe_out[1]) == 0, "");
//      solAssert(close(pipe_in[0]) == 0, "");
//      solAssert(close(pipe_in[1]) == 0, "");
//      execl("/usr/bin/z3", "z3", "-smt2", "-in", NULL);
//      exit(1); /* Only reached if execl() failed */
//  }
//}

//}

SMTLib2Interface::SMTLib2Interface()
{
    // TODO using pipes did not really work, so trying it the hard way for now.
//  createSubprocess(m_solverWrite, m_solverRead);
//  solAssert(m_solverWrite, "Unable to start Z3");
//  solAssert(m_solverRead, "Unable to start Z3");
//  write("(set-option :produce-models true)\n(set-logic QF_LIA)\n");
    reset();
}

SMTLib2Interface::~SMTLib2Interface()
{
//  if (m_solverWrite)
//  {
//      write("(exit)\n");
//      fflush(m_solverWrite);
//      fclose(m_solverWrite);
//      m_solverWrite = nullptr;
//  }
//  if (m_solverRead)
//  {
//      fclose(m_solverRead);
//      m_solverRead = nullptr;
//  }
}

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

void SMTLib2Interface::push()
{
    m_accumulatedOutput.emplace_back();
    //write("(push)\n");
}

void SMTLib2Interface::pop()
{
    //write("(pop)\n");
    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") +
        ")\n"
    );
    return Expression(_name, {});
}

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

Expression SMTLib2Interface::newBool(string _name)
{
    write("(declare-const |" + _name + "| Bool)\n");
    return Expression(_name, {});
}

void SMTLib2Interface::addAssertion(Expression _expr)
{
    write("(assert " + _expr.toSExpr() + ")\n");
}

pair<CheckResult, vector<string>> SMTLib2Interface::check(vector<Expression> const& _expressionsToEvaluate)
{
    string checks;
    if (_expressionsToEvaluate.empty())
        checks = "(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...
            checks += "(declare-const |EVALEXPR_" + to_string(i) + "| Int)\n";
            checks += "(assert (= |EVALEXPR_" + to_string(i) + "| " + e.toSExpr() + "))\n";
        }
        checks += "(check-sat)\n";
        checks += "(get-value (";
        for (size_t i = 0; i < _expressionsToEvaluate.size(); i++)
            checks += "|EVALEXPR_" + to_string(i) + "| ";
        checks += "))\n";
    }
    string response = communicate(boost::algorithm::join(m_accumulatedOutput, "\n") + checks);
    CheckResult result;
    // TODO proper parsing
    if (boost::starts_with(response, "sat\n"))
        result = CheckResult::SAT;
    else if (boost::starts_with(response, "unsat\n"))
        result = CheckResult::UNSAT;
    else if (boost::starts_with(response, "unknown\n"))
        result = CheckResult::UNKNOWN;
    else
        solAssert(false, "Invalid response to check-sat: " + response);

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

//string SMTLib2Interface::eval(Expression _expr)
//{
//  write("(get-value (" + _expr.toSExpr() + ")\n");
//  std::string reply = communicate();
//  cout << "<-- Z3: " << reply << endl;
//  // TODO parse
//  return reply;
//}

void SMTLib2Interface::write(string _data)
{
//  cout << " --> Z3: " << _data << endl;
//  solAssert(m_solverWrite, "");
//  solAssert(fputs(_data.c_str(), m_solverWrite) >= 0 || true, "EOF while communicating with Z3.");
//  solAssert(fflush(m_solverWrite) == 0 || true, "");
    solAssert(!m_accumulatedOutput.empty(), "");
    m_accumulatedOutput.back() += move(_data);
}

string SMTLib2Interface::communicate(std::string const& _input)
{
    ofstream("/tmp/z3exchange.smt2") << _input << "(exit)" << endl;
    FILE* solverOutput = popen("z3 -smt2 /tmp/z3exchange.smt2", "r");
    string result;
    array<char, 128> buffer;
    while (!feof(solverOutput))
        if (fgets(buffer.data(), 127, solverOutput) != nullptr)
            result += buffer.data();
    fclose(solverOutput);
    return result;
}

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;
}