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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/>.
*/
// SPDX-License-Identifier: GPL-3.0
/**
* Class that can answer questions about values of variables and their relations.
*/
#pragma once
#include <libyul/ASTForward.h>
#include <libyul/YulString.h>
#include <libsolutil/Common.h>
#include <libsolutil/Numeric.h>
#include <map>
#include <functional>
namespace solidity::yul
{
struct Dialect;
struct AssignedValue;
/**
* Class that can answer questions about values of variables and their relations.
*/
class KnowledgeBase
{
public:
KnowledgeBase(
Dialect const& _dialect,
std::function<AssignedValue const*(YulString)> _variableValues
):
m_dialect(_dialect),
m_variableValues(std::move(_variableValues))
{}
bool knownToBeDifferent(YulString _a, YulString _b);
std::optional<u256> differenceIfKnownConstant(YulString _a, YulString _b);
bool knownToBeDifferentByAtLeast32(YulString _a, YulString _b);
bool knownToBeEqual(YulString _a, YulString _b) const { return _a == _b; }
bool knownToBeZero(YulString _a);
std::optional<u256> valueIfKnownConstant(YulString _a);
private:
Expression simplify(Expression _expression);
Expression simplifyRecursively(Expression _expression);
Dialect const& m_dialect;
std::function<AssignedValue const*(YulString)> m_variableValues;
size_t m_counter = 0;
};
}