--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/IR/MetadataImpl.h	Wed Feb 18 14:55:36 2015 +0900
@@ -0,0 +1,46 @@
+//===- MetadataImpl.h - Helpers for implementing metadata -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file has private helpers for implementing metadata types.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_METADATAIMPL_H
+#define LLVM_IR_METADATAIMPL_H
+
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/IR/Metadata.h"
+
+namespace llvm {
+
+template <class T, class InfoT>
+static T *getUniqued(DenseSet<T *, InfoT> &Store,
+                     const typename InfoT::KeyTy &Key) {
+  auto I = Store.find_as(Key);
+  return I == Store.end() ? nullptr : *I;
+}
+
+template <class T, class StoreT>
+T *MDNode::storeImpl(T *N, StorageType Storage, StoreT &Store) {
+  switch (Storage) {
+  case Uniqued:
+    Store.insert(N);
+    break;
+  case Distinct:
+    N->storeDistinctInContext();
+    break;
+  case Temporary:
+    break;
+  }
+  return N;
+}
+
+} // end namespace llvm
+
+#endif