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			121 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			121 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*(
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| 	This file is part of solidity.
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| 
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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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| 
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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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| 
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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 variables by their most recently assigned expressions.
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|  */
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| 
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| #include <libyul/optimiser/Rematerialiser.h>
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| 
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| #include <libyul/optimiser/Metrics.h>
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| #include <libyul/optimiser/ASTCopier.h>
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| #include <libyul/optimiser/NameCollector.h>
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| #include <libyul/Exceptions.h>
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| #include <libyul/AST.h>
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| 
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| #include <range/v3/algorithm/all_of.hpp>
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| 
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| using namespace std;
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| using namespace solidity;
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| using namespace solidity::yul;
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| 
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| void Rematerialiser::run(Dialect const& _dialect, Block& _ast, set<YulString> _varsToAlwaysRematerialize)
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| {
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| 	Rematerialiser{_dialect, _ast, std::move(_varsToAlwaysRematerialize)}(_ast);
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| }
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| 
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| void Rematerialiser::run(
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| 	Dialect const& _dialect,
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| 	FunctionDefinition& _function,
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| 	set<YulString> _varsToAlwaysRematerialize
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| )
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| {
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| 	Rematerialiser{_dialect, _function, std::move(_varsToAlwaysRematerialize)}(_function);
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| }
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| 
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| Rematerialiser::Rematerialiser(
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| 	Dialect const& _dialect,
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| 	Block& _ast,
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| 	set<YulString> _varsToAlwaysRematerialize
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| ):
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| 	DataFlowAnalyzer(_dialect),
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| 	m_referenceCounts(ReferencesCounter::countReferences(_ast)),
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| 	m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize))
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| {
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| }
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| 
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| Rematerialiser::Rematerialiser(
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| 	Dialect const& _dialect,
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| 	FunctionDefinition& _function,
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| 	set<YulString> _varsToAlwaysRematerialize
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| ):
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| 	DataFlowAnalyzer(_dialect),
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| 	m_referenceCounts(ReferencesCounter::countReferences(_function)),
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| 	m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize))
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| {
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| }
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| 
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| void Rematerialiser::visit(Expression& _e)
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| {
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| 	if (holds_alternative<Identifier>(_e))
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| 	{
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| 		Identifier& identifier = std::get<Identifier>(_e);
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| 		YulString 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).value, OptimizerException, "");
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| 			AssignedValue const& value = m_value.at(name);
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| 			size_t refs = m_referenceCounts[name];
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| 			size_t cost = CodeCost::codeCost(m_dialect, *value.value);
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| 			if (
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| 				(refs <= 1 && value.loopDepth == m_loopDepth) ||
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| 				cost == 0 ||
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| 				(refs <= 5 && cost <= 1 && m_loopDepth == 0) ||
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| 				m_varsToAlwaysRematerialize.count(name)
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| 			)
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| 			{
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| 				assertThrow(m_referenceCounts[name] > 0, OptimizerException, "");
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| 				if (ranges::all_of(m_references[name], [&](auto const& ref) { return inScope(ref); }))
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| 				{
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| 					// update reference counts
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| 					m_referenceCounts[name]--;
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| 					for (auto const& ref: ReferencesCounter::countReferences(*value.value))
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| 						m_referenceCounts[ref.first] += ref.second;
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| 					_e = (ASTCopier{}).translate(*value.value);
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| 				}
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| 			}
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| 		}
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| 	}
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| 	DataFlowAnalyzer::visit(_e);
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| }
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| 
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| void LiteralRematerialiser::visit(Expression& _e)
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| {
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| 	if (holds_alternative<Identifier>(_e))
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| 	{
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| 		Identifier& identifier = std::get<Identifier>(_e);
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| 		YulString name = identifier.name;
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| 		if (m_value.count(name))
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| 		{
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| 			Expression const* value = m_value.at(name).value;
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| 			assertThrow(value, OptimizerException, "");
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| 			if (holds_alternative<Literal>(*value))
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| 				_e = *value;
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| 		}
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| 	}
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| 	DataFlowAnalyzer::visit(_e);
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| }
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