/*

  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

/**

 * Counts the number of references to a variable.

 */

#pragma once

#include <libyul/optimiser/ASTWalker.h>

#include <libyul/Scope.h>

namespace solidity::yul

{

struct AsmAnalysisInfo;

/**

 * Counts the number of references to a variable. This includes actual (read) references

 * but also assignments to the variable. It does not include the declaration itself or

 * function parameters, but it does include function return parameters.

 *

 * This component can handle multiple variables of the same name.

 *

 * Can only be applied to strict assembly.

 */

struct VariableReferenceCounter: public yul::ASTWalker

{

public:

  static std::map<Scope::Variable const*, unsigned> run(AsmAnalysisInfo const& _assemblyInfo, Block const& _block)

  {

    VariableReferenceCounter variableReferenceCounter(_assemblyInfo);

    variableReferenceCounter(_block);

    return std::move(variableReferenceCounter.m_variableReferences);

  }

protected:

  void operator()(Block const& _block) override;

  void operator()(Identifier const& _identifier) override;

  void operator()(FunctionDefinition const&) override;

  void operator()(ForLoop const&) override;

private:

  explicit VariableReferenceCounter(

    AsmAnalysisInfo const& _assemblyInfo

  ): m_info(_assemblyInfo)

  {}

  void increaseRefIfFound(YulName _variableName);

  AsmAnalysisInfo const& m_info;

  Scope* m_scope = nullptr;

  std::map<Scope::Variable const*, unsigned> m_variableReferences;

};

}