diff --git a/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp b/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp
index 134b01f0f65..a70b0dcd8f8 100644
--- a/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp
+++ b/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp
@@ -339,6 +339,9 @@ private:
           assert(TargetSymbol && "No target symbol from parsePairRelocation?");
           break;
         }
+        case PCRel32TLV:
+          return make_error<JITLinkError>(
+              "MachO TLV relocations not yet supported");
         default:
           llvm_unreachable("Special relocation kind should not appear in "
                            "mach-o file");