RFR [XS] Subclasses of jdk.jfr.Event loaded from CDS breaks -XX:FlightRecorderOptions=retransform=false

[Jiangli Zhou]

Hi Ioi,

SystemDictionary::reorder_dictionary_for_sharing() and Dictionary::reorder_dictionary_for_sharing() are only used for CDS code. Could you please add CDS_ONLY() to the function definitions and put the implementation under #if INCLUDE_CDS.

Thanks,
Jiangli
 
> On Oct 26, 2017, at 4:26 PM, Ioi Lam <ioi.lam at oracle.com> wrote:
> 
> Please review the follow change:
> 
>     https://bugs.openjdk.java.net/browse/JDK-8190191
> http://cr.openjdk.java.net/~iklam/jdk10/8190191-jfr-event-retransform-false.v01.open/
> 
> Background:
> 
> When -XX:FlightRecorderOptions=retransform=false is given in the command-line,
> subclasses of jdk.jfr.Event are instrumented at load time with information that's
> specific to the current JVM lifetime. As a result, we cannot perform
> such instrumentation at CDS dump time.
> 
> A more complicated CDS solution would load these classes from the archive,
> and re-do the runtime instrumentation. However, there are only a very
> small number of these classes. The performance benefit of archiving them
> does not justify the extra complication.
> 
> Hence, in this fix, we just identify these classes and exclude them
> from the CDS archive during run time.
> 
> (Because JFR is still a closed feature, the test cases are in the closed repo ...)
> 
> Thanks
> - Ioi
>