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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/>.
*/
/**
* Specific AST walkers that collect semantical facts.
*/
#pragma once
#include <libyul/optimiser/ASTWalker.h>
#include <set>
namespace yul
{
/**
* Specific AST walker that determines whether an expression is movable.
*/
class MovableChecker: public ASTWalker
{
public:
MovableChecker() = default;
explicit MovableChecker(Expression const& _expression);
void operator()(Identifier const& _identifier) override;
void operator()(FunctionalInstruction const& _functionalInstruction) override;
void operator()(FunctionCall const& _functionCall) override;
/// Disallow visiting anything apart from Expressions (this throws).
void visit(Statement const&) override;
using ASTWalker::visit;
bool movable() const { return m_movable; }
std::set<YulString> const& referencedVariables() const { return m_variableReferences; }
private:
/// Which variables the current expression references.
std::set<YulString> m_variableReferences;
/// Is the current expression movable or not.
bool m_movable = true;
};
}
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