RFR(S) 8230677: Should disable Escape Analysis if JVMTI capability can_get_owned_monitor_info was taken

[Daniel D. Daugherty]

Based on the review thread, it looks like Richard has run Tier1 tests on
this change. I don't think there are any JVM/TI tests in Tier1. I'm not
sure how much compiler testing is done in Tier1, but I do know that the
compiler stress testing doesn't kick in until the later tiers (Tier5 or
Tier6)...

Serguei, with your JVM/TI hat on, what kind of additional testing (if any)
do you think we need here?

Dan


On 9/25/19 6:20 AM, Reingruber, Richard wrote:
> Thank you Vladimir and also David and Serguei for your Reviews.
>
>    > May be add comment that it is onload capability and can't be changed during execution.
>
> Done.
>
> I'll be out-of-office next week. Will push when coming back.
>
> Thanks, Richard.
>
> -----Original Message-----
> From: Vladimir Kozlov <vladimir.kozlov at oracle.com>
> Sent: Dienstag, 24. September 2019 21:04
> To: Reingruber, Richard <richard.reingruber at sap.com>; hotspot-compiler-dev at openjdk.java.net; serviceability-dev at openjdk.java.net
> Subject: Re: RFR(S) 8230677: Should disable Escape Analysis if JVMTI capability can_get_owned_monitor_info was taken
>
> I read discussion and this change looks good to me.
>
> May be add comment that it is onload capability and can't be changed during execution.
>
> Thanks,
> Vladimir
>
> On 9/6/19 7:24 AM, Reingruber, Richard wrote:
>> Hi,
>>
>> could I please get reviews for
>>
>> Webrev: http://cr.openjdk.java.net/~rrich/webrevs/2019/8230677/webrev.0/
>> Bug:    https://bugs.openjdk.java.net/browse/JDK-8230677
>>
>> The JVMTI functions GetOwnedMonitorInfo() and GetOwnedMonitorStackDepthInfo() can be used to
>> retrieve objects locked by a thread. In terms of escape analysis those references escape and
>> optimizations like scalar replacement become invalid.
>>
>> The runtime currently cannot cope with objects escaping through JVMTI (try included
>> tests). Therefore escape analysis should be disabled if an agent requests the capabilities
>> can_get_owned_monitor_info or can_get_owned_monitor_stack_depth_info.
>>
>> This was taken out of JDK-8227745 [1] to make it smaller. With JDK-8227745 there's no need to
>> disable escape analysis, instead optimizations based on escape analysis will be reverted just before
>> objects escape through JVMTI.
>>
>> I've run tier1 tests.
>>
>> Thanks, Richard.
>>
>> [1] https://bugs.openjdk.java.net/browse/JDK-8227745
>>