mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
160 lines
4.3 KiB
C++
160 lines
4.3 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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* Base class for both UnusedAssignEliminator and UnusedStoreEliminator.
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*/
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#include <libyul/optimiser/UnusedStoreBase.h>
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#include <libyul/optimiser/Semantics.h>
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#include <libyul/optimiser/OptimiserStep.h>
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#include <libyul/AST.h>
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#include <libsolutil/CommonData.h>
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#include <range/v3/action/remove_if.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 UnusedStoreBase::operator()(If const& _if)
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{
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visit(*_if.condition);
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TrackedStores skipBranch{m_stores};
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(*this)(_if.body);
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merge(m_stores, move(skipBranch));
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}
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void UnusedStoreBase::operator()(Switch const& _switch)
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{
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visit(*_switch.expression);
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TrackedStores const preState{m_stores};
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bool hasDefault = false;
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vector<TrackedStores> branches;
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for (auto const& c: _switch.cases)
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{
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if (!c.value)
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hasDefault = true;
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(*this)(c.body);
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branches.emplace_back(move(m_stores));
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m_stores = preState;
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}
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if (hasDefault)
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{
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m_stores = move(branches.back());
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branches.pop_back();
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}
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for (auto& branch: branches)
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merge(m_stores, move(branch));
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}
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void UnusedStoreBase::operator()(FunctionDefinition const& _functionDefinition)
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{
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ScopedSaveAndRestore outerAssignments(m_stores, {});
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ScopedSaveAndRestore forLoopInfo(m_forLoopInfo, {});
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ScopedSaveAndRestore forLoopNestingDepth(m_forLoopNestingDepth, 0);
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(*this)(_functionDefinition.body);
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finalizeFunctionDefinition(_functionDefinition);
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}
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void UnusedStoreBase::operator()(ForLoop const& _forLoop)
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{
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ScopedSaveAndRestore outerForLoopInfo(m_forLoopInfo, {});
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ScopedSaveAndRestore forLoopNestingDepth(m_forLoopNestingDepth, m_forLoopNestingDepth + 1);
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// If the pre block was not empty,
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// we would have to deal with more complicated scoping rules.
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assertThrow(_forLoop.pre.statements.empty(), OptimizerException, "");
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// We just run the loop twice to account for the back edge.
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// There need not be more runs because we only have three different states.
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visit(*_forLoop.condition);
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TrackedStores zeroRuns{m_stores};
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(*this)(_forLoop.body);
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merge(m_stores, move(m_forLoopInfo.pendingContinueStmts));
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m_forLoopInfo.pendingContinueStmts = {};
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(*this)(_forLoop.post);
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visit(*_forLoop.condition);
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if (m_forLoopNestingDepth < 6)
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{
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// Do the second run only for small nesting depths to avoid horrible runtime.
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TrackedStores oneRun{m_stores};
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(*this)(_forLoop.body);
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merge(m_stores, move(m_forLoopInfo.pendingContinueStmts));
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m_forLoopInfo.pendingContinueStmts.clear();
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(*this)(_forLoop.post);
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visit(*_forLoop.condition);
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// Order of merging does not matter because "max" is commutative and associative.
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merge(m_stores, move(oneRun));
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}
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else
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// Shortcut to avoid horrible runtime.
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shortcutNestedLoop(zeroRuns);
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// Order of merging does not matter because "max" is commutative and associative.
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merge(m_stores, move(zeroRuns));
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merge(m_stores, move(m_forLoopInfo.pendingBreakStmts));
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m_forLoopInfo.pendingBreakStmts.clear();
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}
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void UnusedStoreBase::operator()(Break const&)
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{
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m_forLoopInfo.pendingBreakStmts.emplace_back(move(m_stores));
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m_stores.clear();
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}
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void UnusedStoreBase::operator()(Continue const&)
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{
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m_forLoopInfo.pendingContinueStmts.emplace_back(move(m_stores));
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m_stores.clear();
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}
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void UnusedStoreBase::merge(TrackedStores& _target, TrackedStores&& _other)
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{
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util::joinMap(_target, move(_other), [](
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map<Statement const*, State>& _assignmentHere,
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map<Statement const*, State>&& _assignmentThere
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)
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{
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return util::joinMap(_assignmentHere, move(_assignmentThere), State::join);
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});
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}
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void UnusedStoreBase::merge(TrackedStores& _target, vector<TrackedStores>&& _source)
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{
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for (TrackedStores& ts: _source)
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merge(_target, move(ts));
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_source.clear();
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}
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