diff --git a/llvm/lib/DebugInfo/CodeView/DebugCrossExSubsection.cpp b/llvm/lib/DebugInfo/CodeView/DebugCrossExSubsection.cpp
new file mode 100644
index 0000000..d8dca5d
--- /dev/null
+++ b/llvm/lib/DebugInfo/CodeView/DebugCrossExSubsection.cpp
@@ -0,0 +1,49 @@
+//===- DebugCrossExSubsection.cpp -------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/CodeView/DebugCrossExSubsection.h"
+
+#include "llvm/DebugInfo/CodeView/CodeViewError.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+
+Error DebugCrossModuleExportsSubsectionRef::initialize(
+    BinaryStreamReader Reader) {
+  if (Reader.bytesRemaining() % sizeof(CrossModuleExport) != 0)
+    return make_error<CodeViewError>(
+        cv_error_code::corrupt_record,
+        "Cross Scope Exports section is an invalid size!");
+
+  uint32_t Size = Reader.bytesRemaining() / sizeof(CrossModuleExport);
+  return Reader.readArray(References, Size);
+}
+
+Error DebugCrossModuleExportsSubsectionRef::initialize(BinaryStreamRef Stream) {
+  BinaryStreamReader Reader(Stream);
+  return initialize(Reader);
+}
+
+void DebugCrossModuleExportsSubsection::addMapping(uint32_t Local,
+                                                   uint32_t Global) {
+  Mappings[Local] = Global;
+}
+
+uint32_t DebugCrossModuleExportsSubsection::calculateSerializedSize() const {
+  return Mappings.size() * sizeof(CrossModuleExport);
+}
+
+Error DebugCrossModuleExportsSubsection::commit(
+    BinaryStreamWriter &Writer) const {
+  for (const auto &M : Mappings) {
+    if (auto EC = Writer.writeObject(M))
+      return EC;
+  }
+  return Error::success();
+}