RFR (XS): [MVT] Support Q-types in MHs.constant()

[Maurizio Cimadamore]

Looks good

Moving forward I have a concern on adding more capabilities to 
MethodHandles/MethodHandles.lookup.

On the one hand it's cool that we're trying to tweak things so that they 
'just work' - that is, let devs use existing MH capabilities to 
create/combine value-based handles.

On the other hand, this makes the surface area of MVT very blurry, as it 
becomes harder to see where standard JDK ends and where MVT begins. This 
could be problematic if, e.g. at some point we needed to move all the 
MVT stuff under an experimental incubator module.

So, I'm starting to wonder if we shouldn't just add a ValueHandles 
class, similar to MethodHandles.

In other words - have a ValueHandles class which contains the relevant 
methods from ValueType plus the ones we've tweaked inside MethodHandles. 
And have a ValueHandles.Lookup class to perform getter and wither lookup 
on values.

What do you think?

Maurizio


On 11/07/17 18:43, Vladimir Ivanov wrote:
> http://cr.openjdk.java.net/~vlivanov/valhalla/8184184/webrev.00/
>
> Support Q-types in MHs.constant().
>
> Testing: jdk/test/valhalla/mvt/
>
> Best regards,
> Vladimir Ivanov