consolidated VM notes for primitive classes

[Peter Levart]

Hi,

I just noticed the following statement in the presented document:

 > If a primitive object is composed of a combination of scalars and 
references to identity objects, the problem is less hopeless, though 
still complicated. A primitive object becomes unreachable (in the 
modified definition of the previous paragraph) if and only if at least 
one of its component identity object references becomes unreachable.

If this did see an implementation in the VM, we would essentially get 
muti-referent Ephemeron(s) out of it. Not very easy to implement though.


Regards, Peter


On 4/21/21 8:51 AM, John Rose wrote:
> Brian and I hammered out a document this week that
> captures what we think is emerging as our shared
> understanding of how adapt the JVM to support
> primitive classes.
>
> It is still white-hot, not even off the press, but I think
> it is worth looking it even in its unfinished state.
>
> https://github.com/openjdk/valhalla-docs/blob/main/site/design-notes/state-of-valhalla/03-vm-model.md 
> <https://github.com/openjdk/valhalla-docs/blob/main/site/design-notes/state-of-valhalla/03-vm-model.md>
>
> That is the JVM side, only.  Most of it is already
> prototyped in HotSpot, some is not.
>
> I’ll let Brian speak for the valhalla-doc repository
> as a whole, but I wanted to get this out there for
> tomorrow’s meeting.
>
> — John