/*

  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 <libsolidity/ast/AST.h>

#include <libsolidity/analysis/ControlFlowGraph.h>

#include <libsolutil/Algorithms.h>

namespace solidity::frontend

{

/**

 * Analyses all function flows and recursively removes all exit edges from CFG

 * nodes that make function calls that will always revert.

 */

class ControlFlowRevertPruner

{

public:

  ControlFlowRevertPruner(CFG& _cfg): m_cfg(_cfg) {}

  void run();

private:

  /// Possible revert states of a function call

  enum class RevertState

  {

    AllPathsRevert,

    HasNonRevertingPath,

    Unknown,

  };

  /// Identify revert states of all function flows

  void findRevertStates();

  /// Modify function flows so that edges with reverting function calls are removed

  void modifyFunctionFlows();

  /// Control Flow Graph object.

  CFG& m_cfg;

  /// function/contract pairs mapped to their according revert state

  std::map<CFG::FunctionContractTuple, RevertState> m_functions;

  std::map<

    std::tuple<FunctionCall const*, ContractDefinition const*>,

    FunctionDefinition const*

  > m_resolveCache;

};

}