It crashes with Bus Error right after emitting the jitWrite thunk. Looks like this is due to the mapping of the jitWrite thunk pages being changed to execute only immediately after generating and linking the code. With async disassembly, we can't read the code to disassemble. <rdar://problem/30124488>
Created attachment 301401 [details] Patch
Committed r212262: <http://trac.webkit.org/changeset/212262>