Unify blocks with shared code.

1 files changed, 69 insertions, 0 deletions

diff --git a/BlockDeduplicator.h b/BlockDeduplicator.h
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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 <cstddef>
+#include <vector>
+#include <functional>
+
+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();
+
+private:
+	/// Iterator that skips tags skips to the end if (all branches of) the control
+	/// flow does not continue to the next instruction.
+	struct BlockIterator: std::iterator<std::forward_iterator_tag, AssemblyItem const>
+	{
+	public:
+		BlockIterator(AssemblyItems::const_iterator _it, AssemblyItems::const_iterator _end):
+			it(_it), end(_end) { }
+		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 { return *it; }
+		AssemblyItems::const_iterator it;
+		AssemblyItems::const_iterator end;
+	};
+
+	AssemblyItems& m_items;
+};
+
+}
+}