diff -r 274361bd6915 -r 0f9a54a13803 src/hotspot/share/runtime/arguments.cpp
--- a/src/hotspot/share/runtime/arguments.cpp	Thu Mar 07 10:22:19 2019 +0100
+++ b/src/hotspot/share/runtime/arguments.cpp	Thu Mar 07 10:32:55 2019 +0100
@@ -530,6 +530,7 @@
   { "UseMembar",                    JDK_Version::jdk(10), JDK_Version::jdk(12), JDK_Version::undefined() },
   { "CompilationPolicyChoice",      JDK_Version::jdk(13), JDK_Version::jdk(14), JDK_Version::undefined() },
   { "FailOverToOldVerifier",        JDK_Version::jdk(13), JDK_Version::jdk(14), JDK_Version::undefined() },
+  { "ThreadLocalHandshakes",        JDK_Version::jdk(13), JDK_Version::jdk(14), JDK_Version::jdk(15) },
 
   // --- Deprecated alias flags (see also aliased_jvm_flags) - sorted by obsolete_in then expired_in:
   { "DefaultMaxRAMFraction",        JDK_Version::jdk(8),  JDK_Version::undefined(), JDK_Version::undefined() },