mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
72 lines
2.0 KiB
C
72 lines
2.0 KiB
C
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/*
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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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#pragma once
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#include <libyul/optimiser/ASTWalker.h>
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#include <libyul/optimiser/OptimiserStep.h>
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#include <libyul/Dialect.h>
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#include <libdevcore/Common.h>
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namespace yul
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{
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/**
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* Conditional simplifier.
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*
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* Inserts assignments to condition variables if the value can be determined
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* from the control-flow.
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*
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* Destroys SSA form.
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*
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* Currently, this tool is very limited, mostly because we do not yet have support
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* for boolean types. Since conditions only check for expressions being nonzero,
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* we cannot assign a specific value.
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*
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* Current features:
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* - switch cases: insert "<condition> := <caseLabel>"
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* - after if statement with terminating control-flow, insert "<condition> := 0"
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*
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* Future features:
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* - allow replacements by "1"
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* - take termination of user-defined functions into account
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*
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* Works best with SSA form and if dead code removal has run before.
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*
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* Prerequisite: Disambiguator.
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*/
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class ConditionalSimplifier: public ASTModifier
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{
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public:
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static constexpr char const* name{"ConditionalSimplifier"};
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static void run(OptimiserStepContext& _context, Block& _ast)
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{
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ConditionalSimplifier{_context.dialect}(_ast);
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}
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using ASTModifier::operator();
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void operator()(Switch& _switch) override;
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void operator()(Block& _block) override;
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private:
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explicit ConditionalSimplifier(Dialect const& _dialect):
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m_dialect(_dialect)
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{}
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Dialect const& m_dialect;
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};
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}
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