diff options
Diffstat (limited to 'BlockDeduplicator.cpp')
-rw-r--r-- | BlockDeduplicator.cpp | 75 |
1 files changed, 55 insertions, 20 deletions
diff --git a/BlockDeduplicator.cpp b/BlockDeduplicator.cpp index eadbe1b4..d930ea22 100644 --- a/BlockDeduplicator.cpp +++ b/BlockDeduplicator.cpp @@ -35,13 +35,33 @@ bool BlockDeduplicator::deduplicate() { // Compares indices based on the suffix that starts there, ignoring tags and stopping at // opcodes that stop the control flow. + + // Virtual tag that signifies "the current block" and which is used to optimise loops. + // We abort if this virtual tag actually exists. + AssemblyItem pushSelf(PushTag, u256(-4)); + if ( + std::count(m_items.cbegin(), m_items.cend(), pushSelf.tag()) || + std::count(m_items.cbegin(), m_items.cend(), pushSelf.pushTag()) + ) + return false; + function<bool(size_t, size_t)> comparator = [&](size_t _i, size_t _j) { if (_i == _j) return false; - BlockIterator first(m_items.begin() + _i, m_items.end()); - BlockIterator second(m_items.begin() + _j, m_items.end()); + // To compare recursive loops, we have to already unify PushTag opcodes of the + // block's own tag. + AssemblyItem pushFirstTag(pushSelf); + AssemblyItem pushSecondTag(pushSelf); + + if (_i < m_items.size() && m_items.at(_i).type() == Tag) + pushFirstTag = m_items.at(_i).pushTag(); + if (_j < m_items.size() && m_items.at(_j).type() == Tag) + pushSecondTag = m_items.at(_j).pushTag(); + + BlockIterator first(m_items.begin() + _i, m_items.end(), &pushFirstTag, &pushSelf); + BlockIterator second(m_items.begin() + _j, m_items.end(), &pushSecondTag, &pushSelf); BlockIterator end(m_items.end(), m_items.end()); if (first != end && (*first).type() == Tag) @@ -52,27 +72,34 @@ bool BlockDeduplicator::deduplicate() return std::lexicographical_compare(first, end, second, end); }; - set<size_t, function<bool(size_t, size_t)>> blocksSeen(comparator); - map<u256, u256> tagReplacement; - for (size_t i = 0; i < m_items.size(); ++i) + size_t iterations = 0; + for (; ; ++iterations) { - if (m_items.at(i).type() != Tag) - continue; - auto it = blocksSeen.find(i); - if (it == blocksSeen.end()) - blocksSeen.insert(i); - else - tagReplacement[m_items.at(i).data()] = m_items.at(*it).data(); - } - - bool ret = false; - for (AssemblyItem& item: m_items) - if (item.type() == PushTag && tagReplacement.count(item.data())) + //@todo this should probably be optimized. + set<size_t, function<bool(size_t, size_t)>> blocksSeen(comparator); + map<u256, u256> tagReplacement; + for (size_t i = 0; i < m_items.size(); ++i) { - ret = true; - item.setData(tagReplacement.at(item.data())); + if (m_items.at(i).type() != Tag) + continue; + auto it = blocksSeen.find(i); + if (it == blocksSeen.end()) + blocksSeen.insert(i); + else + tagReplacement[m_items.at(i).data()] = m_items.at(*it).data(); } - return ret; + + bool changed = false; + for (AssemblyItem& item: m_items) + if (item.type() == PushTag && tagReplacement.count(item.data())) + { + changed = true; + item.setData(tagReplacement.at(item.data())); + } + if (!changed) + break; + } + return iterations > 0; } BlockDeduplicator::BlockIterator& BlockDeduplicator::BlockIterator::operator++() @@ -89,3 +116,11 @@ BlockDeduplicator::BlockIterator& BlockDeduplicator::BlockIterator::operator++() } return *this; } + +AssemblyItem const& BlockDeduplicator::BlockIterator::operator*() const +{ + if (replaceItem && replaceWith && *it == *replaceItem) + return *replaceWith; + else + return *it; +} |