drreg: register spilling mediation framework

From bruen...@google.com on July 10, 2011 16:52:53

we plan to build a "drreg" extension that provides register liveness analysis and stealing. one thing we didn't plan to do but we may want to is to add a feature to permanently steal a register. when only need access to a few fields though, directly-addressable TLS should be more performant: but when have a lot of fields a stolen register could be more efficient.

Original issue: http://code.google.com/p/dynamorio/issues/detail?id=511