RFR: JDK-8205549 JDK-8205698 Support of flattened values in Unsafe

[Karen Kinnear]

Frederic,

Many thanks for doing this so quickly!
The code looks good.

I only had one minor question - 

1. allocate_buffered_or_heap_instance
   - I assume that for unsafe you always want a heap instance?
   - I recognize that today this will always return a heap instance

thanks,
Karen

> On Jun 27, 2018, at 5:17 PM, Frederic Parain <frederic.parain at oracle.com> wrote:
> 
> Please review this changeset which adds support for flattened values to the Unsafe API.
> 
> http://cr.openjdk.java.net/~fparain/Unsafe/webrev.02/index.html
> 
> This changeset addresses the following issues:
>  - reading from /writing to a flattenable/flattened field with Unsafe
>  - null-check when writing to a flattenable field
>  - initialization barrier when reading an uninitialized static value field with Unsafe
>  - enforcing values immutability even when using Unsafe
>  - reading from /writing to a value array with Unsafe
>  - null-check when writing to a value array with Unsafe
> 
> Thanks,
> 
> Fred
>