Various thinks use JITSTACKFRAME_ARGS_INDEX as a scratch area in Source/JavaScriptCore/jit/ThunkGenerators.cpp.
Michael said he is fixing this as a part of Bug 122980.
(In reply to comment #1) > Michael said he is fixing this as a part of Bug 122980. I'm not working on this one.
Created attachment 214526 [details] Patch
Committed r157609: <http://trac.webkit.org/changeset/157609>