solidity/libsmtutil/SolverInterface.h
2021-05-26 22:12:49 +02:00

413 lines
13 KiB
C++

/*
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/>.
*/
// SPDX-License-Identifier: GPL-3.0
#pragma once
#include <libsmtutil/Exceptions.h>
#include <libsmtutil/Sorts.h>
#include <libsolutil/Common.h>
#include <cstdio>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <vector>
namespace solidity::smtutil
{
struct SMTSolverChoice
{
bool cvc4 = false;
bool z3 = false;
static constexpr SMTSolverChoice All() { return {true, true}; }
static constexpr SMTSolverChoice CVC4() { return {true, false}; }
static constexpr SMTSolverChoice Z3() { return {false, true}; }
static constexpr SMTSolverChoice None() { return {false, false}; }
bool none() { return !some(); }
bool some() { return cvc4 || z3; }
bool all() { return cvc4 && z3; }
};
enum class CheckResult
{
SATISFIABLE, UNSATISFIABLE, UNKNOWN, CONFLICTING, ERROR
};
/// C++ representation of an SMTLIB2 expression.
class Expression
{
friend class SolverInterface;
public:
explicit Expression(bool _v): Expression(_v ? "true" : "false", Kind::Bool) {}
explicit Expression(std::shared_ptr<SortSort> _sort, std::string _name = ""): Expression(std::move(_name), {}, _sort) {}
explicit Expression(std::string _name, std::vector<Expression> _arguments, SortPointer _sort):
name(std::move(_name)), arguments(std::move(_arguments)), sort(std::move(_sort)) {}
Expression(size_t _number): Expression(std::to_string(_number), {}, SortProvider::sintSort) {}
Expression(u256 const& _number): Expression(_number.str(), {}, SortProvider::sintSort) {}
Expression(s256 const& _number): Expression(_number.sign() >= 0 ? _number.str() : "-", _number.sign() >= 0 ? std::vector<Expression>{} : std::vector<Expression>{Expression(size_t(0)), u256(-_number)}, SortProvider::sintSort) {}
Expression(bigint const& _number): Expression(_number.sign() >= 0 ? _number.str() : "-", _number.sign() >= 0 ? std::vector<Expression>{} : std::vector<Expression>{Expression(size_t(0)), u256(-_number)}, SortProvider::sintSort) {}
Expression(Expression const&) = default;
Expression(Expression&&) = default;
Expression& operator=(Expression const&) = default;
Expression& operator=(Expression&&) = default;
bool hasCorrectArity() const
{
if (name == "tuple_constructor")
{
auto tupleSort = std::dynamic_pointer_cast<TupleSort>(sort);
smtAssert(tupleSort, "");
return arguments.size() == tupleSort->components.size();
}
static std::map<std::string, unsigned> const operatorsArity{
{"ite", 3},
{"not", 1},
{"and", 2},
{"or", 2},
{"=>", 2},
{"=", 2},
{"<", 2},
{"<=", 2},
{">", 2},
{">=", 2},
{"+", 2},
{"-", 2},
{"*", 2},
{"div", 2},
{"mod", 2},
{"bvnot", 1},
{"bvand", 2},
{"bvor", 2},
{"bvxor", 2},
{"bvshl", 2},
{"bvlshr", 2},
{"bvashr", 2},
{"int2bv", 2},
{"bv2int", 1},
{"select", 2},
{"store", 3},
{"const_array", 2},
{"tuple_get", 2}
};
return operatorsArity.count(name) && operatorsArity.at(name) == arguments.size();
}
static Expression ite(Expression _condition, Expression _trueValue, Expression _falseValue)
{
smtAssert(*_trueValue.sort == *_falseValue.sort, "");
SortPointer sort = _trueValue.sort;
return Expression("ite", std::vector<Expression>{
std::move(_condition), std::move(_trueValue), std::move(_falseValue)
}, std::move(sort));
}
static Expression implies(Expression _a, Expression _b)
{
return Expression(
"=>",
std::move(_a),
std::move(_b),
Kind::Bool
);
}
/// select is the SMT representation of an array index access.
static Expression select(Expression _array, Expression _index)
{
smtAssert(_array.sort->kind == Kind::Array, "");
std::shared_ptr<ArraySort> arraySort = std::dynamic_pointer_cast<ArraySort>(_array.sort);
smtAssert(arraySort, "");
smtAssert(_index.sort, "");
smtAssert(*arraySort->domain == *_index.sort, "");
return Expression(
"select",
std::vector<Expression>{std::move(_array), std::move(_index)},
arraySort->range
);
}
/// store is the SMT representation of an assignment to array index.
/// The function is pure and returns the modified array.
static Expression store(Expression _array, Expression _index, Expression _element)
{
auto arraySort = std::dynamic_pointer_cast<ArraySort>(_array.sort);
smtAssert(arraySort, "");
smtAssert(_index.sort, "");
smtAssert(_element.sort, "");
smtAssert(*arraySort->domain == *_index.sort, "");
smtAssert(*arraySort->range == *_element.sort, "");
return Expression(
"store",
std::vector<Expression>{std::move(_array), std::move(_index), std::move(_element)},
arraySort
);
}
static Expression const_array(Expression _sort, Expression _value)
{
smtAssert(_sort.sort->kind == Kind::Sort, "");
auto sortSort = std::dynamic_pointer_cast<SortSort>(_sort.sort);
auto arraySort = std::dynamic_pointer_cast<ArraySort>(sortSort->inner);
smtAssert(sortSort && arraySort, "");
smtAssert(_value.sort, "");
smtAssert(*arraySort->range == *_value.sort, "");
return Expression(
"const_array",
std::vector<Expression>{std::move(_sort), std::move(_value)},
arraySort
);
}
static Expression tuple_get(Expression _tuple, size_t _index)
{
smtAssert(_tuple.sort->kind == Kind::Tuple, "");
std::shared_ptr<TupleSort> tupleSort = std::dynamic_pointer_cast<TupleSort>(_tuple.sort);
smtAssert(tupleSort, "");
smtAssert(_index < tupleSort->components.size(), "");
return Expression(
"tuple_get",
std::vector<Expression>{std::move(_tuple), Expression(_index)},
tupleSort->components.at(_index)
);
}
static Expression tuple_constructor(Expression _tuple, std::vector<Expression> _arguments)
{
smtAssert(_tuple.sort->kind == Kind::Sort, "");
auto sortSort = std::dynamic_pointer_cast<SortSort>(_tuple.sort);
auto tupleSort = std::dynamic_pointer_cast<TupleSort>(sortSort->inner);
smtAssert(tupleSort, "");
smtAssert(_arguments.size() == tupleSort->components.size(), "");
return Expression(
"tuple_constructor",
std::move(_arguments),
tupleSort
);
}
static Expression int2bv(Expression _n, size_t _size)
{
smtAssert(_n.sort->kind == Kind::Int, "");
std::shared_ptr<IntSort> intSort = std::dynamic_pointer_cast<IntSort>(_n.sort);
smtAssert(intSort, "");
smtAssert(_size <= 256, "");
return Expression(
"int2bv",
std::vector<Expression>{std::move(_n), Expression(_size)},
std::make_shared<BitVectorSort>(_size)
);
}
static Expression bv2int(Expression _bv, bool _signed = false)
{
smtAssert(_bv.sort->kind == Kind::BitVector, "");
std::shared_ptr<BitVectorSort> bvSort = std::dynamic_pointer_cast<BitVectorSort>(_bv.sort);
smtAssert(bvSort, "");
smtAssert(bvSort->size <= 256, "");
return Expression(
"bv2int",
std::vector<Expression>{std::move(_bv)},
SortProvider::intSort(_signed)
);
}
friend Expression operator!(Expression _a)
{
if (_a.sort->kind == Kind::BitVector)
return ~_a;
return Expression("not", std::move(_a), Kind::Bool);
}
friend Expression operator&&(Expression _a, Expression _b)
{
if (_a.sort->kind == Kind::BitVector)
{
smtAssert(_b.sort->kind == Kind::BitVector, "");
return _a & _b;
}
return Expression("and", std::move(_a), std::move(_b), Kind::Bool);
}
friend Expression operator||(Expression _a, Expression _b)
{
if (_a.sort->kind == Kind::BitVector)
{
smtAssert(_b.sort->kind == Kind::BitVector, "");
return _a | _b;
}
return Expression("or", std::move(_a), std::move(_b), Kind::Bool);
}
friend Expression operator==(Expression _a, Expression _b)
{
smtAssert(_a.sort->kind == _b.sort->kind, "Trying to create an 'equal' expression with different sorts");
return Expression("=", std::move(_a), std::move(_b), Kind::Bool);
}
friend Expression operator!=(Expression _a, Expression _b)
{
return !(std::move(_a) == std::move(_b));
}
friend Expression operator<(Expression _a, Expression _b)
{
return Expression("<", std::move(_a), std::move(_b), Kind::Bool);
}
friend Expression operator<=(Expression _a, Expression _b)
{
return Expression("<=", std::move(_a), std::move(_b), Kind::Bool);
}
friend Expression operator>(Expression _a, Expression _b)
{
return Expression(">", std::move(_a), std::move(_b), Kind::Bool);
}
friend Expression operator>=(Expression _a, Expression _b)
{
return Expression(">=", std::move(_a), std::move(_b), Kind::Bool);
}
friend Expression operator+(Expression _a, Expression _b)
{
auto intSort = _a.sort;
return Expression("+", {std::move(_a), std::move(_b)}, intSort);
}
friend Expression operator-(Expression _a, Expression _b)
{
auto intSort = _a.sort;
return Expression("-", {std::move(_a), std::move(_b)}, intSort);
}
friend Expression operator*(Expression _a, Expression _b)
{
auto intSort = _a.sort;
return Expression("*", {std::move(_a), std::move(_b)}, intSort);
}
friend Expression operator/(Expression _a, Expression _b)
{
auto intSort = _a.sort;
return Expression("div", {std::move(_a), std::move(_b)}, intSort);
}
friend Expression operator%(Expression _a, Expression _b)
{
auto intSort = _a.sort;
return Expression("mod", {std::move(_a), std::move(_b)}, intSort);
}
friend Expression operator~(Expression _a)
{
auto bvSort = _a.sort;
return Expression("bvnot", {std::move(_a)}, bvSort);
}
friend Expression operator&(Expression _a, Expression _b)
{
auto bvSort = _a.sort;
return Expression("bvand", {std::move(_a), std::move(_b)}, bvSort);
}
friend Expression operator|(Expression _a, Expression _b)
{
auto bvSort = _a.sort;
return Expression("bvor", {std::move(_a), std::move(_b)}, bvSort);
}
friend Expression operator^(Expression _a, Expression _b)
{
auto bvSort = _a.sort;
return Expression("bvxor", {std::move(_a), std::move(_b)}, bvSort);
}
friend Expression operator<<(Expression _a, Expression _b)
{
auto bvSort = _a.sort;
return Expression("bvshl", {std::move(_a), std::move(_b)}, bvSort);
}
friend Expression operator>>(Expression _a, Expression _b)
{
auto bvSort = _a.sort;
return Expression("bvlshr", {std::move(_a), std::move(_b)}, bvSort);
}
static Expression ashr(Expression _a, Expression _b)
{
auto bvSort = _a.sort;
return Expression("bvashr", {std::move(_a), std::move(_b)}, bvSort);
}
Expression operator()(std::vector<Expression> _arguments) const
{
smtAssert(
sort->kind == Kind::Function,
"Attempted function application to non-function."
);
auto fSort = dynamic_cast<FunctionSort const*>(sort.get());
smtAssert(fSort, "");
return Expression(name, std::move(_arguments), fSort->codomain);
}
std::string name;
std::vector<Expression> arguments;
SortPointer sort;
private:
/// Manual constructors, should only be used by SolverInterface and this class itself.
Expression(std::string _name, std::vector<Expression> _arguments, Kind _kind):
Expression(std::move(_name), std::move(_arguments), std::make_shared<Sort>(_kind)) {}
explicit Expression(std::string _name, Kind _kind):
Expression(std::move(_name), std::vector<Expression>{}, _kind) {}
Expression(std::string _name, Expression _arg, Kind _kind):
Expression(std::move(_name), std::vector<Expression>{std::move(_arg)}, _kind) {}
Expression(std::string _name, Expression _arg1, Expression _arg2, Kind _kind):
Expression(std::move(_name), std::vector<Expression>{std::move(_arg1), std::move(_arg2)}, _kind) {}
};
DEV_SIMPLE_EXCEPTION(SolverError);
class SolverInterface
{
public:
SolverInterface(std::optional<unsigned> _queryTimeout = {}): m_queryTimeout(_queryTimeout) {}
virtual ~SolverInterface() = default;
virtual void reset() = 0;
virtual void push() = 0;
virtual void pop() = 0;
virtual void declareVariable(std::string const& _name, SortPointer const& _sort) = 0;
Expression newVariable(std::string _name, SortPointer const& _sort)
{
// Subclasses should do something here
smtAssert(_sort, "");
declareVariable(_name, _sort);
return Expression(std::move(_name), {}, _sort);
}
virtual void addAssertion(Expression const& _expr) = 0;
/// Checks for satisfiability, evaluates the expressions if a model
/// is available. Throws SMTSolverError on error.
virtual std::pair<CheckResult, std::vector<std::string>>
check(std::vector<Expression> const& _expressionsToEvaluate) = 0;
/// @returns a list of queries that the system was not able to respond to.
virtual std::vector<std::string> unhandledQueries() { return {}; }
/// @returns how many SMT solvers this interface has.
virtual size_t solvers() { return 1; }
protected:
std::optional<unsigned> m_queryTimeout;
};
}