/*
	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;

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;
}