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/*
This file is part of cpp-ethereum.
cpp-ethereum is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
cpp-ethereum is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file BlockDeduplicator.h
* @author Christian <c@ethdev.com>
* @date 2015
* Unifies basic blocks that share content.
*/
#pragma once
#include <libdevcore/Common.h>
#include <cstddef>
#include <vector>
#include <functional>
#include <map>
namespace dev
{
namespace eth
{
class AssemblyItem;
using AssemblyItems = std::vector<AssemblyItem>;
/**
* Optimizer class to be used to unify blocks that share content.
* Modifies the passed vector in place.
*/
class BlockDeduplicator
{
public:
BlockDeduplicator(AssemblyItems& _items): m_items(_items) {}
/// @returns true if something was changed
bool deduplicate();
/// @returns the tags that were replaced.
std::map<u256, u256> const& replacedTags() const { return m_replacedTags; }
/// Replaces all PushTag operations insied @a _items that match a key in
/// @a _replacements by the respective value. If @a _subID is not -1, only
/// apply the replacement for foreign tags from this sub id.
/// @returns true iff a replacement was performed.
static bool applyTagReplacement(
AssemblyItems& _items,
std::map<u256, u256> const& _replacements,
size_t _subID = size_t(-1)
);
private:
/// Iterator that skips tags and skips to the end if (all branches of) the control
/// flow does not continue to the next instruction.
/// If the arguments are supplied to the constructor, replaces items on the fly.
struct BlockIterator: std::iterator<std::forward_iterator_tag, AssemblyItem const>
{
public:
BlockIterator(
AssemblyItems::const_iterator _it,
AssemblyItems::const_iterator _end,
AssemblyItem const* _replaceItem = nullptr,
AssemblyItem const* _replaceWith = nullptr
):
it(_it), end(_end), replaceItem(_replaceItem), replaceWith(_replaceWith) {}
BlockIterator& operator++();
bool operator==(BlockIterator const& _other) const { return it == _other.it; }
bool operator!=(BlockIterator const& _other) const { return it != _other.it; }
AssemblyItem const& operator*() const;
AssemblyItems::const_iterator it;
AssemblyItems::const_iterator end;
AssemblyItem const* replaceItem;
AssemblyItem const* replaceWith;
};
std::map<u256, u256> m_replacedTags;
AssemblyItems& m_items;
};
}
}
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