[aarch64-port-dev ] AARCH64: 8064611: Changes to HotSpot shared code

[Dean Long]

On 11/18/2014 7:03 PM, Vladimir Kozlov wrote:
> Yes, we can hide AARCH64 using something similar to 
> CODE_CACHE_SIZE_LIMIT macro which could be overwritten in platform 
> specific files if needed: USE_STORE_RELEASE_FOR_VOLATILE.
> Or slightly more complicated declaration similar to 
> support_IRIW_for_not_multiple_copy_atomic_cpu boolean constant.
>
> Dean, will it help us if we do that? If yes, then we should do that.
>
Yes, this will help us.  Following the boolean constant example, we 
would have something like:

#ifdef USE_STORE_RELEASE_FOR_VOLATILE
const bool use_store_release_for_volatile = true;
#else
const bool use_store_release_for_volatile = false;
#endif

> I did not insisted on removing AARCH64 from C2 because there was 
> discussion about generating special volatile load/store nodes instead 
> of using memory order flag. So we may rewrite this code anyway.
>
I like the sound of this, but do we still need a way to turn it off, so 
that platforms that emit explicit
barriers can still collapse redundant barriers?  Please file a bug/RFE 
for this so we don't forget it.

dl

> Regards,
> Vladimir
>
> On 11/18/14 5:52 PM, Dean Long wrote:
>> That would be my preference too, but then we have to touch all the other
>> ports.
>> I'll let Vladimir have the final vote.
>>
>> dl
>>
>> On 11/18/2014 1:38 AM, Roland Westrelin wrote:
>>> There’s very little code that’s marked with #ifdef X86 or #ifdef SPARC
>>> in the C2 code. Wouldn’t we want to hide everything that is AARCH64
>>> specific behind functions in Matcher like we do elsewhere?
>>>
>>> Roland.
>>