Review Request: Improved stack overflow handling for Zero

[Gary Benson]

Hi all,

I recently started adding stack overflow checking to Shark,
which brought to light a bunch of deficiencies in Zero's
stack overflow code.  Zero had this really odd, look-ahead
overflow handling which was pretty strange, easily fooled,
and in retrospect totally unnecessary.  I'm pretty sure
whoever wrote it was an idiot.

This webrev removes the old overflow detection and replaces
it with something more straightforward and complete:

  http://cr.openjdk.java.net/~gbenson/zero-stack-overflow-checks/

Note that a number of calls to Unimplemented have been removed.
It shouldn't be possible to have an unhandled stack overflow
error with the new code.

As a bonus, the new code is mildly faster (about 2%) due to
the checks being inlined.

I don't have a bug id for this.

Cheers,
Gary

PS I am on vacation for the rest of the week, back Monday 12.

-- 
http://gbenson.net/