mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
108 lines
3.3 KiB
C++
108 lines
3.3 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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#include <libyul/optimiser/ConditionalUnsimplifier.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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#include <libyul/optimiser/NameCollector.h>
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#include <libyul/ControlFlowSideEffectsCollector.h>
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#include <libsolutil/CommonData.h>
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using namespace solidity;
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using namespace solidity::yul;
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using namespace solidity::util;
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void ConditionalUnsimplifier::run(OptimiserStepContext& _context, Block& _ast)
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{
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ConditionalUnsimplifier{
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_context.dialect,
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ControlFlowSideEffectsCollector{_context.dialect, _ast}.functionSideEffectsNamed()
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}(_ast);
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}
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void ConditionalUnsimplifier::operator()(Switch& _switch)
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{
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visit(*_switch.expression);
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if (!std::holds_alternative<Identifier>(*_switch.expression))
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{
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ASTModifier::operator()(_switch);
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return;
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}
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YulString expr = std::get<Identifier>(*_switch.expression).name;
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for (auto& _case: _switch.cases)
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{
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if (_case.value)
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{
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(*this)(*_case.value);
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if (
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!_case.body.statements.empty() &&
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std::holds_alternative<Assignment>(_case.body.statements.front())
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)
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{
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Assignment const& assignment = std::get<Assignment>(_case.body.statements.front());
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if (
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assignment.variableNames.size() == 1 &&
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assignment.variableNames.front().name == expr &&
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std::holds_alternative<Literal>(*assignment.value) &&
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valueOfLiteral(std::get<Literal>(*assignment.value)) == valueOfLiteral(*_case.value)
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)
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_case.body.statements.erase(_case.body.statements.begin());
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}
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}
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(*this)(_case.body);
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}
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}
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void ConditionalUnsimplifier::operator()(Block& _block)
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{
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walkVector(_block.statements);
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iterateReplacingWindow<2>(
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_block.statements,
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[&](Statement& _stmt1, Statement& _stmt2) -> std::optional<std::vector<Statement>>
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{
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if (std::holds_alternative<If>(_stmt1))
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{
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If& _if = std::get<If>(_stmt1);
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if (
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std::holds_alternative<Identifier>(*_if.condition) &&
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!_if.body.statements.empty()
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)
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{
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YulString condition = std::get<Identifier>(*_if.condition).name;
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if (
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std::holds_alternative<Assignment>(_stmt2) &&
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TerminationFinder(m_dialect, &m_functionSideEffects).controlFlowKind(_if.body.statements.back()) !=
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TerminationFinder::ControlFlow::FlowOut
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)
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{
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Assignment const& assignment = std::get<Assignment>(_stmt2);
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if (
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assignment.variableNames.size() == 1 &&
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assignment.variableNames.front().name == condition &&
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std::holds_alternative<Literal>(*assignment.value) &&
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valueOfLiteral(std::get<Literal>(*assignment.value)) == 0
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)
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return {make_vector<Statement>(std::move(_stmt1))};
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}
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}
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}
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return {};
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}
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);
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}
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