[PATCH] Indirect-call topn targets profiler (runtime)

[Rong Xu]

Hi,

I ported the indirect-call topn target profile from google branch. It
implements the algorithm described in "Value profiling and
optimization" by Brad Calder and Peter Feller. This patch is the
runtime support.

Tested with gcc regression tests and the instrumentation patch (in a
separated patch).

Thanks,

-Rong