RFR 8171971: Fix timing bug in JVM management of package export lists

[serguei.spitsyn at oracle.com]

Hi Harold,

It looks pretty good to me.

One question though.

|| src/share/vm/classfile/modules.cpp

   I wonder if a synchronization is needed for the functions like
   Modules::add_module_exports_to_all_unnamed.
   But this is unrelated to your particular fix.
||

Thanks,
Serguei



On 1/18/17 07:05, harold seigel wrote:
> Hi,
>
> Please review this fix for the package export timing holes discussed 
> in JDK-8171971.  The fix reduces the number of PackageEntry fields 
> that are used to maintain a package's export state and uses the 
> Module_lock to protect all access to these fields.
>
> Also, in cases where a package transitions from having qualified 
> exports to being unqualifiedly exported, it fixes the cleanup of its 
> qualified export list by removing the _exported_pending_delete field 
> and using just is_unqual_exported() to determine when the qualified 
> exports list can be purged (at a safepoint).
>
> Open Webrev: http://cr.openjdk.java.net/~hseigel/bug_8171971/webrev/
>
> JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8171971
>
> The fix was tested with the hotspot, java/lang, java/util, java/io, 
> JFR, and other JTReg tests, the JCK lang and VM tests, RBT tier2 - 
> tier5 tests on LinuxX64, and the colocated and non-colocated NSK tests.
>
> Thanks, Harold
>