[Nestmates] RFR: 8189163: [Nestmates] Updated invokeInterface selection/resolution rules

[David Holmes]

Hi Tobias,

On 8/03/2018 6:26 PM, Tobias Hartmann wrote:
> Hi David,
> 
> On 08.03.2018 07:13, David Holmes wrote:
>> On 8/03/2018 8:26 AM, Karen Kinnear wrote:
>>> Code looks good. Wouldn’t hurt to have a compiler person (Tobias?) look at the
>>> dependencies is_witness().
>>
>> I actually directly cc'd Tobias on this RFR, but have not heard from him. Perhaps he is away.
> 
> I've actually seen that and marked the thread as ToDo but didn't get a chance to look at it. Sorry
> for that.

No problem at all.

> 
> Just wondering, the change in dependencies.cpp wasn't necessary for functionality/correctness but is
> just an optimization, right?

No it's necessary. Without it we get an assertion failure:

#  Internal Error 
(/export/users/dh198349/valhalla/repos/valhalla-exp/open/src/hotspot/share/code/dependencies.cpp:686), 
pid=17815, tid=17868
#  assert(counter_changed) failed: failed dependencies, but counter 
didn't change

My thinking was that the is_witness check found the private method and 
considered it an indicator of a failed dependency (which it isn't), but 
no changes had occurred that should have invalidated the dependencies, 
hence the assertion failed.

> The changes look good to me.

Great!

Thanks,
David

> Thanks,
> Tobias
>