Introduce native Z3 support.

This commit is contained in:
chriseth 2017-07-13 21:08:24 +02:00
parent 4cea3d4aa4
commit ab5e3a8f6d
2 changed files with 244 additions and 0 deletions

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/*
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/Z3Interface.h>
#include <libsolidity/interface/Exceptions.h>
#include <libdevcore/CommonIO.h>
using namespace std;
using namespace dev;
using namespace dev::solidity::smt;
Z3Interface::Z3Interface():
m_solver(m_context)
{
}
void Z3Interface::reset()
{
m_constants.clear();
m_functions.clear();
m_solver.reset();
}
void Z3Interface::push()
{
m_solver.push();
}
void Z3Interface::pop()
{
m_solver.pop();
}
Expression Z3Interface::newFunction(string _name, Sort _domain, Sort _codomain)
{
m_functions.insert({_name, m_context.function(_name.c_str(), z3Sort(_domain), z3Sort(_codomain))});
return SolverInterface::newFunction(move(_name), _domain, _codomain);
}
Expression Z3Interface::newInteger(string _name)
{
m_constants.insert({_name, m_context.int_const(_name.c_str())});
return SolverInterface::newInteger(move(_name));
}
Expression Z3Interface::newBool(string _name)
{
m_constants.insert({_name, m_context.bool_const(_name.c_str())});
return SolverInterface::newBool(std::move(_name));
}
void Z3Interface::addAssertion(Expression const& _expr)
{
m_solver.add(toZ3Expr(_expr));
}
pair<CheckResult, vector<string>> Z3Interface::check(vector<Expression> const& _expressionsToEvaluate)
{
CheckResult result;
switch (m_solver.check())
{
case z3::check_result::sat:
result = CheckResult::SAT;
break;
case z3::check_result::unsat:
result = CheckResult::UNSAT;
break;
case z3::check_result::unknown:
result = CheckResult::UNKNOWN;
break;
default:
solAssert(false, "");
}
vector<string> values;
if (result != CheckResult::UNSAT)
{
z3::model m = m_solver.get_model();
for (Expression const& e: _expressionsToEvaluate)
values.push_back(toString(m.eval(toZ3Expr(e))));
}
return make_pair(result, values);
}
z3::expr Z3Interface::toZ3Expr(Expression const& _expr)
{
if (_expr.arguments.empty() && m_constants.count(_expr.name))
return m_constants.at(_expr.name);
z3::expr_vector arguments(m_context);
for (auto const& arg: _expr.arguments)
arguments.push_back(toZ3Expr(arg));
static map<string, unsigned> arity{
{"not", 1},
{"and", 2},
{"or", 2},
{"=", 2},
{"<", 2},
{"<=", 2},
{">", 2},
{">=", 2},
{"+", 2},
{"-", 2},
{"*", 2},
{">=", 2}
};
string const& n = _expr.name;
if (m_functions.count(n))
return m_functions.at(n)(arguments);
else if (m_constants.count(n))
{
solAssert(arguments.empty(), "");
return m_constants.at(n);
}
else if (arguments.empty())
{
// We assume it is an integer...
return m_context.int_val(n.c_str());
}
assert(arity.count(n) && arity.at(n) == arguments.size());
if (n == "not")
return !arguments[0];
else if (n == "and")
return arguments[0] && arguments[1];
else if (n == "or")
return arguments[0] || arguments[1];
else if (n == "=")
return arguments[0] == arguments[1];
else if (n == "<")
return arguments[0] < arguments[1];
else if (n == "<=")
return arguments[0] <= arguments[1];
else if (n == ">")
return arguments[0] > arguments[1];
else if (n == ">=")
return arguments[0] >= arguments[1];
else if (n == "+")
return arguments[0] + arguments[1];
else if (n == "-")
return arguments[0] - arguments[1];
else if (n == "*")
return arguments[0] * arguments[1];
// Cannot reach here.
solAssert(false, "");
return arguments[0];
}
z3::sort Z3Interface::z3Sort(Sort _sort)
{
switch (_sort)
{
case Sort::Bool:
return m_context.bool_sort();
case Sort::Int:
return m_context.int_sort();
default:
break;
}
solAssert(false, "");
// Cannot be reached.
return m_context.int_sort();
}

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/*
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/>.
*/
#pragma once
#include <libsolidity/formal/SolverInterface.h>
#include <boost/noncopyable.hpp>
#include <z3++.h>
namespace dev
{
namespace solidity
{
namespace smt
{
class Z3Interface: public SolverInterface, public boost::noncopyable
{
public:
Z3Interface();
void reset() override;
void push() override;
void pop() override;
Expression newFunction(std::string _name, Sort _domain, Sort _codomain) override;
Expression newInteger(std::string _name) override;
Expression newBool(std::string _name) override;
void addAssertion(Expression const& _expr) override;
std::pair<CheckResult, std::vector<std::string>> check(std::vector<Expression> const& _expressionsToEvaluate) override;
private:
z3::expr toZ3Expr(Expression const& _expr);
z3::sort z3Sort(smt::Sort _sort);
std::string checkSatAndGetValuesCommand(std::vector<Expression> const& _expressionsToEvaluate);
std::vector<std::string> parseValues(std::string::const_iterator _start, std::string::const_iterator _end);
z3::context m_context;
z3::solver m_solver;
std::map<std::string, z3::expr> m_constants;
std::map<std::string, z3::func_decl> m_functions;
};
}
}
}