diff --git a/lib/AST/NestedNameSpecifier.cpp b/lib/AST/NestedNameSpecifier.cpp
new file mode 100644
index 0000000..318c05f
--- /dev/null
+++ b/lib/AST/NestedNameSpecifier.cpp
@@ -0,0 +1,34 @@
+//===--- NestedNameSpecifier.cpp - C++ nested name specifiers -----*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines the NestedNameSpecifier class, which represents
+//  a C++ nested-name-specifier.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/AST/NestedNameSpecifier.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/Type.h"
+using namespace clang;
+
+DeclContext *
+NestedNameSpecifier::computeDeclContext(ASTContext &Context) const {
+  // The simple case: we're storing a DeclContext
+  if ((Data & 0x01) == 0)
+    return reinterpret_cast<DeclContext *>(Data);
+
+  Type *T = getAsType();
+  if (!T)
+    return 0;
+
+  // Retrieve the DeclContext associated with this type.
+  const TagType *TagT = T->getAsTagType();
+  assert(TagT && "No DeclContext from a non-tag type");
+  return TagT->getDecl();
+}