JVM/TI code review request (XS and M) (7182152)

Coleen Phillimore coleen.phillimore at oracle.com
Mon Feb 4 09:28:21 PST 2013

On 2/4/2013 12:26 PM, Daniel D. Daugherty wrote:
> On 2/4/13 10:16 AM, Coleen Phillimore wrote:
>> On 2/4/2013 11:50 AM, Daniel D. Daugherty wrote:
>>> Thanks for the additional comment. Reply below.
>>> On 2/4/13 8:34 AM, Coleen Phillimore wrote:
>>>> On 2/4/2013 10:15 AM, Daniel D. Daugherty wrote:
>>>>> Adding back the missing aliases and people...
>>>> Sorry, I meant to send this re-all.
>>>> I missed something major in my earlier review.
>>>> The metadata->is_valid() flag should only be enabled in debug 
>>>> mode.  It adds a word to all metadata.
>>> Yes, I'm aware that it adds a word to all meta data. My change to
>>> src/share/vm/oops/metadata.hpp was intentional. Personally, I would
>>> prefer that is_valid() remain in the product bits for at least one
>>> release cycle (JDK8). I'm a fan of sanity checks in product bits so
>>> I actually wouldn't mind if it stay there permanently.
>>> However, if you insist, I'll backout the change to
>>> src/share/vm/oops/metadata.hpp and redo the RedefineClasses()
>>> sanity check code to be appropriately #ifdef'ed.
>> Thanks, Dan.  I do.  People are actively trying to reduce metadata 
>> right now, so having this additional word will cause a regression 
>> that will be noticed for a special case. is_valid() is a bit of a 
>> hack too.  It relies on metadata being returned and given a non-zero 
>> bit pattern which is only enabled in debug (iirc).
> I enabled the setting of the non-zero bit pattern also (iirc).
> However, I will back out those changes. I don't want to cause
> grief for the metadata reduction effort.
>> There's also a f1_as_method and f2_as_vfinal_method calls that return 
>> Method* which might make the logic of your if statements simpler in 
>> check_no_old_or_obsolete_entries().
> Yes, Karen mentioned one of those in her review and asked for
> that cleanup to be tracked in a followup bug. I noticed quite
> a few "type cleanups" in that area in HSX-24 and I love them.
> I'm presuming that you did that work, but I haven't chased the
> history to ground.

It was John Rose and Christian for the JSR 292 work.  I can't claim credit.

> Dan
>> Thanks,
>> Coleen

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