RFR(M): 8194490: [JVMCI] Move `iterateFrames` to C++

[Vladimir Kozlov]

On 3/2/18 3:34 AM, Gilles Duboscq wrote:
> Hi Vladimir,
> 
> Sorry about that, somehow i never saw your first message.
> Tom and Doug reviewed the JDK8 version internally.
> 
> Beside the copyright year change of `src/hotspot/share/jvmci/jvmciCompilerToVM.cpp` everything still applies cleanly.
> Should i consider this reviewed?

Yes.

> I guess i should re-run the tests since it's been a while.

Yes, please update to latest jdk/hs sources and run testing again.

Thanks,
Vladimir

> 
>   Gilles
> 
> On 01/03/18 23:58, Vladimir Kozlov wrote:
>> Hi Gilles,
>>
>> What happened to this fix?
>>
>> Testing all passed but it was not pushed.
>>
>> Thanks,
>> Vladimir
>>
>> On 2/1/18 5:21 PM, Vladimir Kozlov wrote:
>>> Thank you, Gilles
>>>
>>> Seems fine to me. Who reviewed it in Labs?
>>>
>>> And thank you for running testing.
>>>
>>> Vladimir
>>>
>>> On 1/22/18 6:58 AM, Gilles Duboscq wrote:
>>>> Hi,
>>>>
>>>> Please review the following fix for `HotSpotStackIntrospection.iterateFrames`.
>>>> It moves the iteration code from Java to C++: this helps with an issue that would arise if the nmethod containing the `iterateFrames` hits and uncommon trap during iteration. IT would change the layout of the top frames which would confuse the stack walking logic. Having this loop in C++ ensure there can be no uncommon trap.
>>>>
>>>> Webrev: http://cr.openjdk.java.net/~gdub/webrev-8194490/
>>>> Issue: https://bugs.openjdk.java.net/browse/JDK-8194490
>>>> Testing: hs-tier1,hs-tier2,hs-precheckin-comp
>>>>
>>>> It's bit unfortunate that we have tests for implementation details of JVMCI (i.e., tests for CompilerToVM) instead of tests for the actual API.
>>>>
>>>> Thanks,
>>>>    Gilles
>>>>