libyul/optimiser/EquivalentFunctionDetector.cpp


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/*
    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/>.
*/
/**
 * Optimiser component that combines syntactically equivalent functions.
 */

#include <libyul/optimiser/EquivalentFunctionDetector.h>
#include <libyul/optimiser/SyntacticalEquality.h>

#include <libyul/AsmData.h>
#include <libyul/optimiser/Metrics.h>

using namespace std;
using namespace dev;
using namespace yul;
using namespace solidity;

void EquivalentFunctionDetector::operator()(FunctionDefinition const& _fun)
{
    RoughHeuristic heuristic(_fun);
    auto& candidates = m_candidates[heuristic];
    for (auto const& candidate: candidates)
        if (SyntacticallyEqual{}.statementEqual(_fun, *candidate))
        {
            m_duplicates[_fun.name] = candidate;
            return;
        }
    candidates.push_back(&_fun);
}

bool EquivalentFunctionDetector::RoughHeuristic::operator<(EquivalentFunctionDetector::RoughHeuristic const& _rhs) const
{
    if (
        std::make_tuple(m_fun.parameters.size(), m_fun.returnVariables.size()) ==
        std::make_tuple(_rhs.m_fun.parameters.size(), _rhs.m_fun.returnVariables.size())
    )
        return codeSize() < _rhs.codeSize();
    else
        return
            std::make_tuple(m_fun.parameters.size(), m_fun.returnVariables.size()) <
            std::make_tuple(_rhs.m_fun.parameters.size(), _rhs.m_fun.returnVariables.size());
}

size_t EquivalentFunctionDetector::RoughHeuristic::codeSize() const
{
    if (!m_codeSize)
        m_codeSize = CodeSize::codeSize(m_fun.body);
    return *m_codeSize;
}