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71 lines
2.1 KiB
71 lines
2.1 KiB
10 years ago
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/*
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This file is part of cpp-ethereum.
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cpp-ethereum 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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cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file CommonSubexpressionEliminator.h
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* @author Christian <c@ethdev.com>
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* @date 2015
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* Optimizer step for common subexpression elimination and stack reorganisation.
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*/
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#pragma once
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#include <vector>
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namespace dev
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{
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namespace eth
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{
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class AssemblyItem;
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/**
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* Optimizer step that performs common subexpression elimination and stack reorginasation,
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* i.e. it tries to infer equality among expressions and compute the values of two expressions
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* known to be equal only once.
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*/
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class CommonSubexpressionEliminator
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{
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public:
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/// Feeds AssemblyItems into the eliminator and @returns the iterator pointing at the first
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/// item that must be fed into a new instance of the eliminator.
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template <class _AssemblyItemIterator>
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_AssemblyItemIterator feedItems(_AssemblyItemIterator _iterator, _AssemblyItemIterator _end);
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/// @returns the resulting items after optimization.
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std::vector<AssemblyItem> getOptimizedItems() const;
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private:
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/// @returns true if the given items starts a new basic block
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bool breaksBasicBlock(AssemblyItem const& _item);
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/// Feeds the item into the system for analysis.
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void feedItem(AssemblyItem const& _item);
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};
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template <class _AssemblyItemIterator>
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_AssemblyItemIterator CommonSubexpressionEliminator::feedItems(
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_AssemblyItemIterator _iterator,
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_AssemblyItemIterator _end
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)
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{
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while (_iterator != _end && !breaksBasicBlock(*_iterator))
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feedItem(*_iterator);
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return _iterator;
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}
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}
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}
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