mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
71 lines
2.3 KiB
C++
71 lines
2.3 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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// SPDX-License-Identifier: GPL-3.0
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/**
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* Optimisation stage that removes mstore and sstore operations if they store the same
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* value that is already known to be in that slot.
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*/
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#include <libyul/optimiser/EqualStoreEliminator.h>
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#include <libyul/optimiser/CallGraphGenerator.h>
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#include <libyul/optimiser/OptimizerUtilities.h>
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#include <libyul/optimiser/Semantics.h>
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#include <libyul/AST.h>
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#include <libyul/Utilities.h>
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using namespace std;
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using namespace solidity;
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using namespace solidity::util;
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using namespace solidity::evmasm;
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using namespace solidity::yul;
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void EqualStoreEliminator::run(OptimiserStepContext const& _context, Block& _ast)
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{
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EqualStoreEliminator eliminator{
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_context.dialect,
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SideEffectsPropagator::sideEffects(_context.dialect, CallGraphGenerator::callGraph(_ast))
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};
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eliminator(_ast);
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StatementRemover remover{eliminator.m_pendingRemovals};
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remover(_ast);
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}
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void EqualStoreEliminator::visit(Statement& _statement)
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{
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// No need to consider potential changes through complex arguments since
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// isSimpleStore only returns something if the arguments are identifiers.
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if (ExpressionStatement const* expression = get_if<ExpressionStatement>(&_statement))
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{
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if (auto vars = isSimpleStore(StoreLoadLocation::Storage, *expression))
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{
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if (auto const* currentValue = valueOrNullptr(m_storage, vars->first))
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if (*currentValue == vars->second)
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m_pendingRemovals.insert(&_statement);
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}
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else if (auto vars = isSimpleStore(StoreLoadLocation::Memory, *expression))
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{
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if (auto const* currentValue = valueOrNullptr(m_memory, vars->first))
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if (*currentValue == vars->second)
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m_pendingRemovals.insert(&_statement);
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}
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}
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DataFlowAnalyzer::visit(_statement);
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}
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