mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
106 lines
3.3 KiB
C++
106 lines
3.3 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 variables by their most recently assigned expressions.
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*/
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#include <libyul/optimiser/Rematerialiser.h>
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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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#include <range/v3/algorithm/all_of.hpp>
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using namespace solidity;
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using namespace solidity::yul;
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void Rematerialiser::run(Dialect const& _dialect, Block& _ast, std::set<YulString> _varsToAlwaysRematerialize, bool _onlySelectedVariables)
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{
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Rematerialiser{_dialect, _ast, std::move(_varsToAlwaysRematerialize), _onlySelectedVariables}(_ast);
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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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std::set<YulString> _varsToAlwaysRematerialize,
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bool _onlySelectedVariables
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):
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DataFlowAnalyzer(_dialect, MemoryAndStorage::Ignore),
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m_referenceCounts(VariableReferencesCounter::countReferences(_ast)),
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m_varsToAlwaysRematerialize(std::move(_varsToAlwaysRematerialize)),
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m_onlySelectedVariables(_onlySelectedVariables)
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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 (std::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 (AssignedValue const* value = variableValue(name))
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{
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assertThrow(value->value, OptimizerException, "");
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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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(
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!m_onlySelectedVariables && (
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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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)
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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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auto variableReferences = references(name);
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if (!variableReferences || ranges::all_of(*variableReferences, [&](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: VariableReferencesCounter::countReferences(
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*value->value
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))
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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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void LiteralRematerialiser::visit(Expression& _e)
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{
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if (std::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 (AssignedValue const* value = variableValue(name))
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{
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assertThrow(value->value, OptimizerException, "");
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if (std::holds_alternative<Literal>(*value->value))
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_e = *value->value;
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}
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}
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DataFlowAnalyzer::visit(_e);
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}
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