mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
64 lines
1.8 KiB
C++
64 lines
1.8 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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* Component that collects variables that are never assigned to and their
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* initial values.
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*/
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#include <libyul/optimiser/SSAValueTracker.h>
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#include <libyul/AsmData.h>
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using namespace std;
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using namespace dev;
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using namespace yul;
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void SSAValueTracker::operator()(Assignment const& _assignment)
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{
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for (auto const& var: _assignment.variableNames)
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m_values.erase(var.name);
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}
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void SSAValueTracker::operator()(FunctionDefinition const& _funDef)
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{
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for (auto const& var: _funDef.returnVariables)
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setValue(var.name, nullptr);
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ASTWalker::operator()(_funDef);
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}
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void SSAValueTracker::operator()(VariableDeclaration const& _varDecl)
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{
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if (!_varDecl.value)
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for (auto const& var: _varDecl.variables)
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setValue(var.name, nullptr);
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else if (_varDecl.variables.size() == 1)
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setValue(_varDecl.variables.front().name, _varDecl.value.get());
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}
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void SSAValueTracker::setValue(YulString _name, Expression const* _value)
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{
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assertThrow(
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m_values.count(_name) == 0,
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OptimizerException,
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"Source needs to be disambiguated."
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);
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static Expression const zero{Literal{{}, LiteralKind::Number, YulString{"0"}, {}}};
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if (!_value)
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_value = &zero;
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m_values[_name] = _value;
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}
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