1 files changed, 62 insertions, 0 deletions
diff --git a/libyul/optimiser/Semantics.cpp b/libyul/optimiser/Semantics.cpp
new file mode 100644
index 00000000..3c49016e
--- /dev/null
+++ b/libyul/optimiser/Semantics.cpp
@@ -0,0 +1,62 @@
+/*(
+	This file is part of solidity.
+
+	solidity 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.
+
+	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * Specific AST walkers that collect semantical facts.
+ */
+
+#include <libyul/optimiser/Semantics.h>
+
+#include <libyul/Exceptions.h>
+
+#include <libsolidity/inlineasm/AsmData.h>
+
+#include <libevmasm/SemanticInformation.h>
+
+#include <libdevcore/CommonData.h>
+
+using namespace std;
+using namespace dev;
+using namespace dev::yul;
+
+MovableChecker::MovableChecker(Expression const& _expression)
+{
+	visit(_expression);
+}
+
+void MovableChecker::operator()(Identifier const& _identifier)
+{
+	ASTWalker::operator()(_identifier);
+	m_variableReferences.emplace(_identifier.name);
+}
+
+void MovableChecker::operator()(FunctionalInstruction const& _instr)
+{
+	if (!eth::SemanticInformation::movable(_instr.instruction))
+		m_movable = false;
+	else
+		ASTWalker::operator()(_instr);
+}
+
+void MovableChecker::operator()(FunctionCall const&)
+{
+	m_movable = false;
+}
+
+void MovableChecker::visit(Statement const&)
+{
+	assertThrow(false, OptimizerException, "Movability for statement requested.");
+}