/src/solidity/libyul/optimiser/SyntacticalEquality.h

Source
/*
  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
/**
 * Component that can compare ASTs for equality on a syntactic basis.
 */

#pragma once

#include <libyul/ASTForward.h>
#include <libyul/YulName.h>

#include <map>
#include <type_traits>

namespace solidity::yul
{


/**
 * Component that can compare ASTs for equality on a syntactic basis.
 * Ignores source locations and allows for different variable names but requires exact matches otherwise.
 * Literals are compared based on their values, e.g., `0x01`, `1`, `"\x01"` and `true` all evaluate as equal.
 * Note that this does not apply to unlimited literal strings, which are never considered equal to normal literals,
 * even when the values would look like identical strings in the source.
 *
 * Prerequisite: Disambiguator (unless only expressions are compared)
 */
class SyntacticallyEqual
{
public:
  bool operator()(Expression const& _lhs, Expression const& _rhs);
  bool operator()(Statement const& _lhs, Statement const& _rhs);

  bool expressionEqual(FunctionCall const& _lhs, FunctionCall const& _rhs);
  bool expressionEqual(Identifier const& _lhs, Identifier const& _rhs);
  bool expressionEqual(FunctionName const& _lhs, FunctionName const& _rhs);
  bool expressionEqual(Literal const& _lhs, Literal const& _rhs);

  bool statementEqual(ExpressionStatement const& _lhs, ExpressionStatement const& _rhs);
  bool statementEqual(Assignment const& _lhs, Assignment const& _rhs);
  bool statementEqual(VariableDeclaration const& _lhs, VariableDeclaration const& _rhs);
  bool statementEqual(FunctionDefinition const& _lhs, FunctionDefinition const& _rhs);
  bool statementEqual(If const& _lhs, If const& _rhs);
  bool statementEqual(Switch const& _lhs, Switch const& _rhs);
  bool switchCaseEqual(Case const& _lhs, Case const& _rhs);
  bool statementEqual(ForLoop const& _lhs, ForLoop const& _rhs);
  bool statementEqual(Break const&, Break const&) { return true; }
  bool statementEqual(Continue const&, Continue const&) { return true; }
  bool statementEqual(Leave const&, Leave const&) { return true; }
  bool statementEqual(Block const& _lhs, Block const& _rhs);
private:
  bool visitDeclaration(NameWithDebugData const& _lhs, NameWithDebugData const& _rhs);

  template<typename U, typename V>
  bool expressionEqual(U const&, V const&, std::enable_if_t<!std::is_same<U, V>::value>* = nullptr)
  {
    return false;
  }

  template<typename U, typename V>
  bool statementEqual(U const&, V const&, std::enable_if_t<!std::is_same<U, V>::value>* = nullptr)
  {
    return false;
  }

  template<typename T, bool (SyntacticallyEqual::*CompareMember)(T const&, T const&)>
  bool compareUniquePtr(std::unique_ptr<T> const& _lhs, std::unique_ptr<T> const& _rhs)
  {
    return (_lhs == _rhs) || (_lhs && _rhs && (this->*CompareMember)(*_lhs, *_rhs));
  }

  std::size_t m_idsUsed = 0;
  std::map<YulName, std::size_t> m_identifiersLHS;
  std::map<YulName, std::size_t> m_identifiersRHS;
};

/**
 * Does the same as SyntacticallyEqual just that the operator() function is const.
 */
struct SyntacticallyEqualExpression
{
  bool operator()(Expression const& _lhs, Expression const& _rhs) const;
};


}

Coverage Report

Created: 2026-07-13 07:08