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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/>.
*/
/**
 * Component that collects variables that are never assigned to and their
 * initial values.
 */

#pragma once

#include <libyul/optimiser/ASTWalker.h>

#include <map>
#include <set>

namespace dev
{
namespace yul
{

/**
 * Class that walks the AST and stores the initial value of each variable
 * that is never assigned to.
 *
 * Prerequisite: Disambiguator
 */
class SSAValueTracker: public ASTWalker
{
public:
    using ASTWalker::operator();
    virtual void operator()(VariableDeclaration const& _varDecl) override;
    virtual void operator()(Assignment const& _assignment) override;

    std::map<YulString, Expression const*> const& values() const { return m_values; }
    Expression const* value(YulString _name) const { return m_values.at(_name); }

private:
    void setValue(YulString _name, Expression const* _value);

    std::map<YulString, Expression const*> m_values;
};

}
}