/*

  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

/**

 * Some useful snippets for the optimiser.

 */

#include <libyul/optimiser/OptimizerUtilities.h>

#include <libyul/backends/evm/EVMDialect.h>

#include <libyul/Dialect.h>

#include <libyul/AST.h>

#include <liblangutil/Token.h>

#include <libsolutil/CommonData.h>

#include <range/v3/action/remove_if.hpp>

using namespace std;

using namespace solidity;

using namespace solidity::langutil;

using namespace solidity::util;

using namespace solidity::yul;

void yul::removeEmptyBlocks(Block& _block)

{

  auto isEmptyBlock = [](Statement const& _st) -> bool {

    return holds_alternative<Block>(_st) && std::get<Block>(_st).statements.empty();

  };

  ranges::actions::remove_if(_block.statements, isEmptyBlock);

}

bool yul::isRestrictedIdentifier(Dialect const& _dialect, YulString const& _identifier)

{

  return _identifier.empty() || TokenTraits::isYulKeyword(_identifier.str()) || _dialect.reservedIdentifier(_identifier);

}

optional<evmasm::Instruction> yul::toEVMInstruction(Dialect const& _dialect, YulString const& _name)

{

  if (auto const* dialect = dynamic_cast<EVMDialect const*>(&_dialect))

    if (BuiltinFunctionForEVM const* builtin = dialect->builtin(_name))

      return builtin->instruction;

  return nullopt;

}

void StatementRemover::operator()(Block& _block)

{

  util::iterateReplacing(

    _block.statements,

    [&](Statement& _statement) -> std::optional<vector<Statement>>

    {

      if (m_toRemove.count(&_statement))

        return {vector<Statement>{}};

      else

        return nullopt;

    }

  );

  ASTModifier::operator()(_block);

}