Index: include/llvm/MC/MCLinkerOptimizationHint.h
===================================================================
--- include/llvm/MC/MCLinkerOptimizationHint.h
+++ include/llvm/MC/MCLinkerOptimizationHint.h
@@ -62,6 +62,7 @@
     MCLOHCaseNameToId(AdrpAdd)
     MCLOHCaseNameToId(AdrpLdrGot)
     .Default(-1);
+#undef MCLOHCaseNameToId
 }
 
 static inline StringRef MCLOHIdToName(MCLOHType Kind) {
@@ -76,7 +77,8 @@
     MCLOHCaseIdToName(AdrpAdd);
     MCLOHCaseIdToName(AdrpLdrGot);
   }
-  return StringRef();
+  return {};
+#undef MCLOHCaseIdToName
 }
 
 static inline int MCLOHIdToNbArgs(MCLOHType Kind) {