mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
84 lines
2.5 KiB
C++
84 lines
2.5 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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*/
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#include <libyul/optimiser/RedundantStoreEliminator.h>
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#include <libyul/optimiser/Semantics.h>
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#include <libyul/AST.h>
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#include <libsolutil/CommonData.h>
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#include <boost/range/algorithm_ext/erase.hpp>
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using namespace std;
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using namespace solidity;
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using namespace solidity::yul;
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void RedundantStoreEliminator::run(OptimiserStepContext& _context, Block& _ast)
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{
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RedundantStoreEliminator rse{_context.dialect};
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rse(_ast);
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}
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void RedundantStoreEliminator::operator()(Block& _block)
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{
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// TODO This is copied from DataflowAnalyzer
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size_t numScopes = m_variableScopes.size();
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pushScope(false);
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map<YulString, size_t> latestStore;
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set<size_t> redundantStores;
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for (size_t i = 0; i < _block.statements.size(); ++i)
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{
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Statement& statement = _block.statements.at(i);
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if (holds_alternative<ExpressionStatement>(statement))
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{
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ExpressionStatement& exprStatement = get<ExpressionStatement>(statement);
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// This mechanism relies on the way the data flow analyzer
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// handles `m_storage`.
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if (auto vars = isSimpleStore(StoreLoadLocation::Storage, exprStatement))
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{
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if (m_storage.count(vars->first) && latestStore.count(vars->first))
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redundantStores.insert(latestStore.at(vars->first));
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latestStore[vars->first] = i;
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}
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}
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ASTModifier::visit(statement);
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}
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popScope();
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assertThrow(numScopes == m_variableScopes.size(), OptimizerException, "");
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DataFlowAnalyzer::operator()(_block);
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if (redundantStores.empty())
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return;
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// The arguments to sstore are identifiers and thus do not have side-effects,
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// because otherwise the statement would not have ended up in `redundantStores`.
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vector<Statement> newStatements;
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for (size_t i = 0; i < _block.statements.size(); ++i)
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{
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if (!redundantStores.count(i))
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newStatements.emplace_back(move(_block.statements.at(i)));
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}
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_block.statements = move(newStatements);
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}
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