diff --git a/llvm/include/llvm/BinaryFormat/Swift.def b/llvm/include/llvm/BinaryFormat/Swift.def
--- a/llvm/include/llvm/BinaryFormat/Swift.def
+++ b/llvm/include/llvm/BinaryFormat/Swift.def
@@ -30,3 +30,4 @@
                      ".sw5prt$B")
 HANDLE_SWIFT_SECTION(acfuncs, "__swift5_acfuncs", "swift5_accessible_functions",
                      ".sw5acfn$B")
+HANDLE_SWIFT_SECTION(mpenum, "__swift5_mpenum", "swift5_mpenum", ".sw5mpen$B")