Reserving an extra slot on the stack

[David Lloyd]

For an experiment I'm working on, I'd like to modify the JVM to
reserve one reference-sized slot (which eventually should be visible
to GC) on every stack frame at a fixed well-known offset (such that I
can reach it via Unsafe from Java-space).  But it appears that the
stack layout code is pretty deep in per-CPU areas.  Is there a generic
mechanism that I've missed?  Like some way to make the compiler act as
if there were one extra local variable or something like that?

-- 
- DML