hg: valhalla/valhalla: [lworld] Withdraw support for the __Flattenable and __NotFlattened field modifiers.

[Srikanth]

Hello Karen,

Yes, I believe both 1 and 2 below are taken care of and any behavior 
contrary to that would be a bug. There is no known bug ATM in this space.

Srikanth

On Wednesday 27 June 2018 07:03 PM, Karen Kinnear wrote:
> To be really really clear what we are asking for for LW1:
>
> 1. Modifiers: __Flattenable, __NotFlattened would be accepted only under -XDAllowFlattenabilityModifiers flag
> Many of the existing tests will need to be modified to add this flag.
>
> 2. ACC_FLATTENABLE
> For LW1, by default all instance fields containing value types would be marked as ACC_FLATTENABLE in the classfile.
> Static fields would not. This continues to work even without the -XDAllowFlattenabilityModifiers flag.
> Please make sure this is true - the patch you sent e.g. ClassWriter looks like that might now be true.
>
> We won’t make LW1 if we change the classfile at this point.
>
> So for the LW1 timeframe, the consensus is NOT to move away from ACC_FLATTENABLE.
>
> Apologies for the confusion,
> Karen
>
>
>
>> On Jun 26, 2018, at 11:40 PM, Srikanth <srikanth.adayapalam at oracle.com> wrote:
>>
>> I am working on it, will push soon.
>>
>> Srikanth
>>
>> On Tuesday 26 June 2018 09:17 PM, Karen Kinnear wrote:
>>> Srikanth, Tobias,
>>>
>>> Yes please to push this patch to move these modifiers under the experimental flag. this is a much better approach.
>>>
>>> LW1 is a really tight deadline right now and we don’t want to cause extra work.
>>> My apologies for missing the implications.
>>>
>>> thank you both,
>>> Karen
>>>
>>>> On Jun 26, 2018, at 7:23 AM, Srikanth <srikanth.adayapalam at oracle.com> wrote:
>>>>
>>>>
>>>> The attached patch would cause the flattenability modifiers to be accepted with their erstwhile syntax and semantics when javac is invoked with -XDallowFlattenabilityModifiers
>>>>
>>>> I'll wait to hear from Karen and push/discard accordingly.
>>>>
>>>> (I am likely away Thursday/Friday, I will be available on Wednesday. Posting a patch here, so if it is required in my absence it can be availed. It passes all langtools tests)
>>>>
>>>> Thanks!
>>>> Srikanth
>>>>
>>>> On Tuesday 26 June 2018 03:38 PM, Srikanth wrote:
>>>>> On Tuesday 26 June 2018 03:32 PM, Tobias Hartmann wrote:
>>>>>> Hi Srikanth,
>>>>>>
>>>>>> On 26.06.2018 11:37, Srikanth wrote:
>>>>>>> I did have an express go from Karen to "nuke" these source level modifiers before proceeding. But in
>>>>>>> light of what you say, I'll take a look and see what is involved in pushing these under an option
>>>>>>> instead.
>>>>>> Thanks for looking into it but we should probably wait for Karen to comment on that. I guess I
>>>>>> missed the discussion/decision of fully removing these modifiers (I thought we just don't want to
>>>>>> support them for LW1).
>>>>> Sounds good to me. I'll keep a patch ready in any case and after hearing from Karen decide to push or discard.
>>>>>
>>>>> I believe the consensus in the VM is to move away fromACC_FLATTENABLE on fields to using the ValueTypes attribute.
>>>>>
>>>>> Your concern below about the code rot is valid.
>>>>>
>>>>> Srikanth
>>>>>>> Even with that many of the tests would need "massaging" but I guess it won't shut you out from
>>>>>>> retaining the support for non-flattened value type fields.
>>>>>> Yes, I'm fine with modifying the tests, I'm just concerned that without testing the implementation
>>>>>> of non-flattenable fields in the JVM, the code will start to rot very soon.
>>>>>>
>>>>>> Thanks,
>>>>>> Tobias
>>>> <flat.txt>