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			85 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			85 lines
		
	
	
		
			2.6 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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 * Base class to perform data flow analysis during AST walks.
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 * Tracks assignments and is used as base class for both Rematerialiser and
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 * Common Subexpression Eliminator.
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 */
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#pragma once
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#include <libjulia/optimiser/ASTWalker.h>
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#include <string>
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#include <map>
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#include <set>
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namespace dev
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{
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namespace julia
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{
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/**
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 * Base class to perform data flow analysis during AST walks.
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 * Tracks assignments and is used as base class for both Rematerialiser and
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 * Common Subexpression Eliminator.
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 *
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 * Prerequisite: Disambiguator
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 */
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class DataFlowAnalyzer: public ASTModifier
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{
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public:
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	using ASTModifier::operator();
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	virtual void operator()(Assignment& _assignment) override;
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	virtual void operator()(VariableDeclaration& _varDecl) override;
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	virtual void operator()(If& _if) override;
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	virtual void operator()(Switch& _switch) override;
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	virtual void operator()(FunctionDefinition&) override;
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	virtual void operator()(ForLoop&) override;
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	virtual void operator()(Block& _block) override;
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protected:
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	/// Registers the assignment.
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	void handleAssignment(std::set<std::string> const& _names, Expression* _value);
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	/// Clears information about the values assigned to the given variables,
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	/// for example at points where control flow is merged.
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	void clearValues(std::set<std::string> const& _names);
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	/// Returns true iff the variable is in scope.
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	bool inScope(std::string const& _variableName) const;
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	/// Current values of variables, always movable.
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	std::map<std::string, Expression const*> m_value;
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	/// m_references[a].contains(b) <=> the current expression assigned to a references b
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	std::map<std::string, std::set<std::string>> m_references;
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	/// m_referencedBy[b].contains(a) <=> the current expression assigned to a references b
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	std::map<std::string, std::set<std::string>> m_referencedBy;
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	struct Scope
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	{
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		explicit Scope(bool _isFunction): isFunction(_isFunction) {}
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		std::set<std::string> variables;
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		bool isFunction;
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	};
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	/// List of scopes.
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	std::vector<Scope> m_variableScopes;
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};
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}
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}
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