The main difference is that instead of ensuring correct invariant when
we store anything into the heap (e.g. read-barrier before reads,
write-barrier before writes, plus a bunch of other stuff), we ensure the
strong invariance on objects when they get loaded, by employing what is
currently our write-barrier.
OK, so how does this work? Sure, the OOP load promotes an object to
tospace, but how do you ensure that the OOP doesn't become stale when
a later phase occurs?
Whenever we start an evacuation phase, we pre-evacuate everything that's
referenced by stack or registers, and update those stack slots and
registers. (We did that with the old barrier-scheme too.)
Roman
