/*

  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 <libevmasm/Instruction.h>

#include <libevmasm/SemanticInformation.h>

namespace solidity::yul

{

/**

 * Side effects of a user-defined or builtin function.

 *

 * Each of the three booleans represents a reachability condition. There is an implied

 * fourth alternative, which is going out of gas while executing the function. Since

 * this can always happen and depends on the supply of gas, it is not considered.

 *

 * If all three booleans are false, it means that the function always leads to infinite

 * recursion.

 */

struct ControlFlowSideEffects

{

  /// If true, the function contains at least one reachable branch that terminates successfully.

  bool canTerminate = false;

  /// If true, the function contains at least one reachable branch that reverts.

  bool canRevert = false;

  /// If true, the function has a regular outgoing control-flow.

  bool canContinue = true;

  bool terminatesOrReverts() const

  {

    return (canTerminate || canRevert) && !canContinue;

  }

  static ControlFlowSideEffects fromInstruction(evmasm::Instruction _instruction)

  {

    ControlFlowSideEffects controlFlowSideEffects;

    if (evmasm::SemanticInformation::terminatesControlFlow(_instruction))

    {

      controlFlowSideEffects.canContinue = false;

      if (evmasm::SemanticInformation::reverts(_instruction))

      {

        controlFlowSideEffects.canTerminate = false;

        controlFlowSideEffects.canRevert = true;

      }

      else

      {

        controlFlowSideEffects.canTerminate = true;

        controlFlowSideEffects.canRevert = false;

      }

    }

    return controlFlowSideEffects;

  }

  /// @returns the worst-case control flow side effects.

  static ControlFlowSideEffects worst()

  {

    return ControlFlowSideEffects{true, true, true};

  }

};

}