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			72 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			72 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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	This file is part of solidity.
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	solidity is free software: you can redistribute it and/or modify
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	it under the terms of the GNU General Public License as published by
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	the Free Software Foundation, either version 3 of the License, or
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	(at your option) any later version.
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	solidity is distributed in the hope that it will be useful,
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	but WITHOUT ANY WARRANTY; without even the implied warranty of
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	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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	GNU General Public License for more details.
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	You should have received a copy of the GNU General Public License
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	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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 * Optimiser component that combines syntactically equivalent functions.
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 */
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#pragma once
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#include <libyul/optimiser/ASTWalker.h>
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#include <libyul/AsmDataForward.h>
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namespace yul
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{
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/**
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 * Optimiser component that detects syntactically equivalent functions.
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 *
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 * Prerequisite: Disambiguator
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 */
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class EquivalentFunctionDetector: public ASTWalker
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{
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public:
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	static std::map<YulString, FunctionDefinition const*> run(Block& _block)
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	{
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		EquivalentFunctionDetector detector{};
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		detector(_block);
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		return std::move(detector.m_duplicates);
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	}
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	using ASTWalker::operator();
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	void operator()(FunctionDefinition const& _fun) override;
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private:
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	EquivalentFunctionDetector() = default;
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	/**
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	 * Fast heuristic to detect distinct, resp. potentially equal functions.
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	 *
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	 * Defines a partial order on function definitions. If two functions
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	 * are comparable (one is "less" than the other), they are distinct.
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	 * If not (neither is "less" than the other), they are *potentially* equal.
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	 */
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	class RoughHeuristic
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	{
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	public:
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		RoughHeuristic(FunctionDefinition const& _fun): m_fun(_fun) {}
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		bool operator<(RoughHeuristic const& _rhs) const;
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	private:
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		std::size_t codeSize() const;
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		FunctionDefinition const& m_fun;
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		mutable boost::optional<std::size_t> m_codeSize;
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		// In case the heuristic doesn't turn out to be good enough, we might want to define a hash function for code blocks.
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	};
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	std::map<RoughHeuristic, std::vector<FunctionDefinition const*>> m_candidates;
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	std::map<YulString, FunctionDefinition const*> m_duplicates;
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};
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}
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