Reachability follow up

We've been having quite an interesting series of conversations at work about this reachability problem. Today, one of my co-workers, Dan Heidinga, pointed out that Microsoft's CLR has the same issue. For CLR Microsoft has provided a special static method called GC.KeepAlive(Object). This acts as a hint to the virtual machine and JIT to extend an object's lifetime, but is otherwise a no-op. There's a good article about the problem on an old MSDN blog here. Note that the author considers and rejects the option of automatically extending the lifetime of all function arguments to the end of their functions on the basis that it impacts codegen and therefore performance.