mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
68 lines
1.8 KiB
C++
68 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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* Optimisation stage that removes unused variables and functions.
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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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* Optimisation stage that removes unused variables and functions.
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*
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* TODO: Also remove intermediate variable assignments from movable expressions
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* which are not referenced until after the next assignment to the same variable.
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*
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* Note that this does not remove circular references.
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*
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* Prerequisite: Disambiguator
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*/
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class UnusedPruner: public ASTModifier
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{
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public:
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explicit UnusedPruner(Block& _ast);
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using ASTModifier::operator();
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virtual void operator()(Block& _block) override;
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// @returns true iff the code changed in the previous run.
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bool shouldRunAgain() const { return m_shouldRunAgain; }
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// Run the pruner until the code does not change anymore.
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static void runUntilStabilised(Block& _ast);
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private:
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bool used(std::string const& _name) const;
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void subtractReferences(std::map<std::string, size_t> const& _subtrahend);
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bool m_shouldRunAgain = false;
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std::map<std::string, size_t> m_references;
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};
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}
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}
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