[aarch64-port-dev ] JDK 13 AArch64 issues to backport

[Andrew Dinn]

n.b. to summarize:

The two String intrinsics are the only ones that might be considered
'critical' but that is borderline.

On 20/06/2019 09:15, Andrew Dinn wrote:
> On 19/06/2019 17:54, Andrew Haley wrote:
>> On 6/19/19 5:37 PM, Andrew Dinn wrote:
>>> Am I supposed to backport them now or is anyone else going to step in?
>>
>> First, please determine whether any of the first set are critical.
> 
> I don't think any of these backports are 'critical' in the sense of a
> must-have. Several of them do cause VM crashes/produce invalid results
> but that is mitigated by the fact that this only happens in rare
> circumstances.
> 
> So, modulo one quibble (see below) I agree with your assessment of all
> the bugs slated for backport to both jdk8u and jdk11u. They are not
> critical. However, you omitted to consider the ones which were only for
> one of the two repos.
> 
> The two issues that are to me most egregious are in the set listed only
> for jdk11u:
> 
>>   8215792: AArch64: String.indexOf generates incorrect result
>>   8218966: AArch64: String.compareTo() can read memory after string
> 
> These both produce invalid results with certain long Strings. I think it
> is quite possible for these to turn up in real applications (indeed, one
> was found during Graal testing of text processing). So, I think it is
> important to fix them.
> 
> There are two patches to restore lost performance that are also well
> worth considering. The first was for jdk8u only:
> 
>>   8216350: AArch64: monitor unlock fast path not called
> 
> The second is the quibble in the jdk8u/11u set:
> 
>>   8217368: AArch64: C2 recursive stack locking optimisation not triggered
> 
> You are right that this does not imply a correctness issue. However it
> does harm locking performance which may matter a lot to some users. So,
> I would still urge backporting these two performance fixes unless you
> are really concerned to keep the backport set absolutely minimal.
> 
> regards,
> 
> 
> Andrew Dinn
> -----------
> Senior Principal Software Engineer
> Red Hat UK Ltd
> Registered in England and Wales under Company Registration No. 03798903
> Directors: Michael Cunningham, Michael ("Mike") O'Neill, Eric Shander
> 

-- 
regards,


Andrew Dinn
-----------
Senior Principal Software Engineer
Red Hat UK Ltd
Registered in England and Wales under Company Registration No. 03798903
Directors: Michael Cunningham, Michael ("Mike") O'Neill, Eric Shander