libyul/optimiser/InlinableExpressionFunctionFinder.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 identifies functions to be inlined.
 */

#include <libyul/optimiser/InlinableExpressionFunctionFinder.h>

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

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

void InlinableExpressionFunctionFinder::operator()(Identifier const& _identifier)
{
    checkAllowed(_identifier.name);
    ASTWalker::operator()(_identifier);
}

void InlinableExpressionFunctionFinder::operator()(FunctionCall const& _funCall)
{
    checkAllowed(_funCall.functionName.name);
    ASTWalker::operator()(_funCall);
}

void InlinableExpressionFunctionFinder::operator()(FunctionDefinition const& _function)
{
    if (_function.returnVariables.size() == 1 && _function.body.statements.size() == 1)
    {
        YulString retVariable = _function.returnVariables.front().name;
        Statement const& bodyStatement = _function.body.statements.front();
        if (bodyStatement.type() == typeid(Assignment))
        {
            Assignment const& assignment = boost::get<Assignment>(bodyStatement);
            if (assignment.variableNames.size() == 1 && assignment.variableNames.front().name == retVariable)
            {
                // FIXME: use code size metric here

                // We cannot overwrite previous settings, because this function definition
                // would not be valid here if we were searching inside a functionally inlinable
                // function body.
                assertThrow(m_disallowedIdentifiers.empty() && !m_foundDisallowedIdentifier, OptimizerException, "");
                m_disallowedIdentifiers = set<YulString>{retVariable, _function.name};
                boost::apply_visitor(*this, *assignment.value);
                if (!m_foundDisallowedIdentifier)
                    m_inlinableFunctions[_function.name] = &_function;
                m_disallowedIdentifiers.clear();
                m_foundDisallowedIdentifier = false;
            }
        }
    }
    ASTWalker::operator()(_function.body);
}