RFR(xs): 8199656: Make slow metaspace verifications switchable in debug builds

[David Holmes]

Hi Thomas,

This seems fine to me.

As it is a develop flag no CSR request is needed. (Under rules we 
recently clarified with CSR group, but which have yet to be documented 
somewhere on the wiki.)

Thanks,
David

On 15/03/2018 5:09 PM, Thomas Stüfe wrote:
> Hi all,
> 
> may I please have reviews for this small rfe:
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8199656
> webrev:
> http://cr.openjdk.java.net/~stuefe/webrevs/8199656-verifymetaspace-switch/webrev.00/webrev/
> 
> We have a number of useful metaspace verifications which are all switched
> off via a const bool in code. This change makes these verifications
> switchable.
> 
> Note: the switch is develop because all the verifications are ASSERT only,
> so it makes no sense to make it the switch diagnostic. If we want the tests
> in product builds too, we need to revise the test code.
> 
> For the effect this has,
> try ./hotspot/variant-server/libjvm/gtest/gtestLauncher.exe
> -XX:-VerifyMetaspace -jdk:./images/jdk/
> --gtest_filter=MetaspaceAllocationTest*. With verifications, runtime almost
> triples in fastdebug.
> 
> Thanks and Kind Regards, Thomas
>