mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
83f326525e
This is the only use of solAssert in libevmasm, and the only dependency on libsolidity. There is no justification for why the illegal state is checked here.
67 lines
1.9 KiB
C++
67 lines
1.9 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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/**
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* @author Alex Beregszaszi
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* Removes unused JUMPDESTs.
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*/
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#include "JumpdestRemover.h"
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#include <libevmasm/AssemblyItem.h>
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using namespace std;
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using namespace dev::eth;
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using namespace dev;
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bool JumpdestRemover::optimise(set<size_t> const& _tagsReferencedFromOutside)
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{
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set<size_t> references{referencedTags(m_items, -1)};
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references.insert(_tagsReferencedFromOutside.begin(), _tagsReferencedFromOutside.end());
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size_t initialSize = m_items.size();
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/// Remove tags which are never referenced.
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auto pend = remove_if(
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m_items.begin(),
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m_items.end(),
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[&](AssemblyItem const& _item)
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{
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if (_item.type() != Tag)
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return false;
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auto asmIdAndTag = _item.splitForeignPushTag();
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assertThrow(asmIdAndTag.first == size_t(-1), OptimizerException, "Sub-assembly tag used as label.");
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size_t tag = asmIdAndTag.second;
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return !references.count(tag);
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}
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);
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m_items.erase(pend, m_items.end());
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return m_items.size() != initialSize;
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}
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set<size_t> JumpdestRemover::referencedTags(AssemblyItems const& _items, size_t _subId)
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{
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set<size_t> ret;
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for (auto const& item: _items)
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if (item.type() == PushTag)
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{
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auto subAndTag = item.splitForeignPushTag();
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if (subAndTag.first == _subId)
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ret.insert(subAndTag.second);
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}
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return ret;
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}
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