Re: [Squeak-VMdev] DING! End of Round One

[Andreas R. <and...@gm...>]

> The instVarAt:put: primitive (and the at:put: primitive for indexed
> access) can just check the immutability bit - the additional overhead
> should be small.
> The inst var assignments in methods are more complicated.
> One possible optimization would be to allow immutability only for old
> objects - when assigning into old objects, we need additional code anyway.
> The beImmutable primitive would make sure that the receiver is either
> old already, or it would move the oldspace boundary to point after the
> objects.
> Does that sound sane?

Something disturbs me about this but I'm not sure what. Maybe it's that
"bit" term - if we'd take the "immutability bit" literally it would mean
we'd have some fairly generic stuff to be dealt with here. So here's another
question: How important is it that *all* objects individually can be tagged
immutable in this way? Would it be sufficient if there would be "certain
kinds" of objects (say, classes which have a special format or similar)
which could be used that way?

Cheers,
  - Andreas