RFR (S) 8227766: CheckUnhandledOops is broken in MemAllocator

[coleen.phillimore at oracle.com]

On 7/17/19 5:43 PM, Lois Foltan wrote:
>
>
> On 7/17/2019 1:48 PM, coleen.phillimore at oracle.com wrote:
>>
>>
>> On 7/17/19 1:01 PM, Lois Foltan wrote:
>>> On 7/17/2019 12:22 PM, coleen.phillimore at oracle.com wrote:
>>>>
>>>> Due to some concerns about MemAllocator performance, and to only 
>>>> create handles when needed, I have retested smaller change:
>>>>
>>>> open webrev at 
>>>> http://cr.openjdk.java.net/~coleenp/2019/8227766.02/webrev
>>>
>>> Looks good.
>>>
>>> gc/shared/memAllocator.cpp
>>> - line #373-375: Since obj is already initialized to NULL to you 
>>> need the else clause?
>>
>> Yes, because CheckUnhandledOops poisons oops that are local 
>> variables, so we have to set it back to zero.  I can add that to the 
>> comment.
>
> Ahh, I missed on line #369 that obj is passed by reference.  Looks 
> good, you have my review.

Yes, thank you!   I don't like that obj is passed by reference but Erik 
convinced me to keep it.
Coleen

> Lois
>
>>
>> Thanks!
>> Coleen
>>>
>>> Thanks,
>>> Lois
>>>
>>>>
>>>> Coleen
>>>>
>>>> On 7/17/19 10:49 AM, coleen.phillimore at oracle.com wrote:
>>>>> Summary: Save oop created in handle more eagerly, so 
>>>>> CheckUnhandledOops doesn't bash it.
>>>>>
>>>>> Also added a test for the case that was failing.  There were a 
>>>>> couple of changes needed to compile CHECK_UNHANDLED_OOPS with 
>>>>> slowdebug, but I reverted the makefile changes for doing that 
>>>>> because I don't think we want it for slowdebug.
>>>>> Lastly, made some changes to make CheckUnhandledOops easier to 
>>>>> debug, and removed an unnecessary clearing, since it's also done 
>>>>> in the transition.
>>>>>
>>>>> Tested with hs-tier1-3 with -XX:+CheckUnhandledOops and without.
>>>>>
>>>>> open webrev at 
>>>>> http://cr.openjdk.java.net/~coleenp/2019/8227766.01/webrev
>>>>> bug link https://bugs.openjdk.java.net/browse/JDK-8227766
>>>>>
>>>>> Thanks,
>>>>> Coleen
>>>>
>>>
>>
>