/*

  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

/**

 * Small useful snippets for the optimiser.

 */

#pragma once

#include <libsolutil/Common.h>

#include <libyul/ASTForward.h>

#include <libyul/Dialect.h>

#include <libyul/optimiser/ASTWalker.h>

#include <liblangutil/EVMVersion.h>

#include <optional>

#include <string_view>

namespace solidity::evmasm

{

enum class Instruction: uint8_t;

}

namespace solidity::yul

{

/// Removes statements that are just empty blocks (non-recursive).

/// If this is run on the outermost block, the FunctionGrouper should be run afterwards to keep

/// the canonical form.

void removeEmptyBlocks(Block& _block);

/// Returns true if a given literal can not be used as an identifier.

/// This includes Yul keywords and builtins of the given dialect.

bool isRestrictedIdentifier(Dialect const& _dialect, std::string_view _identifier);

/// Helper function that returns the instruction, if the `_name` is a BuiltinFunction

std::optional<evmasm::Instruction> toEVMInstruction(Dialect const& _dialect, FunctionName const& _name);

/// Helper function that returns the EVM version from a dialect.

/// It returns the default EVM version if dialect is not an EVMDialect.

langutil::EVMVersion const evmVersionFromDialect(Dialect const& _dialect);

class StatementRemover: public ASTModifier

{

public:

  explicit StatementRemover(std::set<Statement const*> const& _toRemove): m_toRemove(_toRemove) {}

  void operator()(Block& _block) override;

private:

  std::set<Statement const*> const& m_toRemove;

};

}