RFR: 8140584: nmethod::oops_do_marking_epilogue always runs verification code

[Stefan Karlsson]

Hi Vladimir,

On 2015-10-27 16:22, Vladimir Kozlov wrote:
> CodeCache::verify_oops() also calls it unguarded.
>
> I think for complete solution nmethod::verify_oop_relocations() and 
> called from it oop_Relocation::verify_oop_relocation(), 
> verify_value(), const_verify_data_value() and pd_verify_data_value() 
> should be declared and defined in debug build only.

I see what you're saying, but I'm unsure that this is really what we 
want to do.

CodeCache::verify_oops is called from the Universe::verify, that can be 
enabled in product builds by setting -XX:+UnlockDiagnosticVMOptions and 
-XX:+VerifyBeforeGC and/or -XX:+VerifyAfterGC. Maybe we want to change 
the relocation code to use guarantees instead of asserts? So that we can 
get verification of the relocation code in product builds?

Thanks,
StefanK

>
> Thanks,
> Vladimir
>
> On 10/27/15 7:44 PM, Stefan Karlsson wrote:
>> Hi,
>>
>> Please review this patch to remove some unnecessary verification code
>> from our product builds.
>>
>> Today, CodeCache::gc_epilogue() guards the call to
>> nmethod::verify_oop_relocations with DEBUG_ONLY, while
>> nmethod::oops_do_marking_epilogue doesn't. Since
>> nmethod::verify_oop_relocations uses asserts when verifying the
>> relocations, this is just wasted cycles in product builds. This patch
>> adds DEBUG_ONLY to nmethod::oops_do_marking_epilogue.
>>
>> http://cr.openjdk.java.net/~stefank/8140584/webrev.01/
>> https://bugs.openjdk.java.net/browse/JDK-8140584
>>
>> Thanks,
>> StefanK