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			72 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			72 lines
		
	
	
		
			2.2 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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 * Optimisation stage that replaces expressions known to be the current value of a variable
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 * in scope by a reference to that variable.
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 */
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#include <libjulia/optimiser/CommonSubexpressionEliminator.h>
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#include <libjulia/optimiser/Metrics.h>
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#include <libjulia/optimiser/SyntacticalEquality.h>
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#include <libjulia/Exceptions.h>
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#include <libsolidity/inlineasm/AsmData.h>
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using namespace std;
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using namespace dev;
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using namespace dev::julia;
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void CommonSubexpressionEliminator::visit(Expression& _e)
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{
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	// We visit the inner expression first to first simplify inner expressions,
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	// which hopefully allows more matches.
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	// Note that the DataFlowAnalyzer itself only has code for visiting Statements,
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	// so this basically invokes the AST walker directly and thus post-visiting
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	// is also fine with regards to data flow analysis.
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	DataFlowAnalyzer::visit(_e);
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	if (_e.type() == typeid(Identifier))
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	{
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		Identifier& identifier = boost::get<Identifier>(_e);
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		string const& name = identifier.name;
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		if (m_value.count(name))
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		{
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			assertThrow(m_value.at(name), OptimizerException, "");
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			if (m_value.at(name)->type() == typeid(Identifier))
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			{
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				string const& value = boost::get<Identifier>(*m_value.at(name)).name;
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				if (inScope(value))
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					_e = Identifier{locationOf(_e), value};
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			}
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		}
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	}
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	else
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	{
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		// TODO this search is rather inefficient.
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		for (auto const& var: m_value)
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		{
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			assertThrow(var.second, OptimizerException, "");
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			if (SyntacticalEqualityChecker::equal(_e, *var.second))
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			{
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				_e = Identifier{locationOf(_e), var.first};
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				break;
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			}
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		}
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	}
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}
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