--- ./Source/JavaScriptCore/assembler/AbstractMacroAssembler.h~	2020-09-20 16:08:53.156883980 +0000

+++ ./Source/JavaScriptCore/assembler/AbstractMacroAssembler.h	2020-09-20 17:18:06.814227632 +0000

@@ -918,14 +918,17 @@

     {

 #if USE(JUMP_ISLANDS)

         switch (nearCall.callMode()) {

         case NearCallMode::Tail:

             return CodeLocationLabel<destTag>(tagCodePtr<destTag>(AssemblerType::prepareForAtomicRelinkJumpConcurrently(nearCall.dataLocation(), destination.dataLocation())));

         case NearCallMode::Regular:

             return CodeLocationLabel<destTag>(tagCodePtr<destTag>(AssemblerType::prepareForAtomicRelinkCallConcurrently(nearCall.dataLocation(), destination.untaggedExecutableAddress())));

+        default:

+            UNUSED_PARAM(nearCall);

+            return destination;

         }

 #else

         UNUSED_PARAM(nearCall);

         return destination;

 #endif

     }