4-th round RFR (XS) 8068162: jvmtiRedefineClasses.cpp: guarantee(false) failed: OLD and/or OBSOLETE method(s) found

[Coleen Phillimore]

Hi Serguei,

Sorry this got lost in my mailbox, twice.  This change looks great!   
Thank you for re-enabling the test.

Thanks,
Coleen

On 1/16/15, 5:38 PM, serguei.spitsyn at oracle.com wrote:
> Just wanted to tell that Dan is the second reviewer,
> so there is no pressure on others to review this. :)
>
> Thanks, Dan!
> Serguei
>
> On 1/16/15 11:16 AM, serguei.spitsyn at oracle.com wrote:
>> Sorry for the re-post.
>> Forgot to add review candidates to the to-list.
>>
>> Thanks,
>> Serguei
>>
>> On 1/16/15 11:14 AM, serguei.spitsyn at oracle.com wrote:
>>> Dan, David H. or David C.,
>>>
>>> May I ask one of you to look at the webrev below?
>>> The issue itself is a little bit tricky, so it is not easy to review 
>>> despite the small size.
>>>
>>> Coleen,
>>>
>>> Does the webrev matches what we discussed with you?
>>> Do you give me a thumbs up?
>>>
>>> Thanks,
>>> Serguei
>>>
>>> May I ask
>>>
>>> On 1/13/15 9:47 PM, serguei.spitsyn at oracle.com wrote:
>>>> Please, review the fix for:
>>>>   https://bugs.openjdk.java.net/browse/JDK-8068162
>>>>
>>>>
>>>> Open webrevs:
>>>> http://cr.openjdk.java.net/~sspitsyn/webrevs/2015/hotspot/8068162-JVMTI-old.4/ 
>>>>
>>>> http://cr.openjdk.java.net/~sspitsyn/webrevs/2015/jdk/8068162-Test-IsModifiableAgent/ 
>>>>
>>>>
>>>>
>>>> Summary:
>>>>
>>>>    The sun.misc.Unsafe:throwIllegalAccessError() method is used in 
>>>> place of a default
>>>>    interface method in the itable if a default method was not 
>>>> defined in the interface.
>>>>    In fact, it happens for two interfaces that purhaps are 
>>>> auto-generated:
>>>>      java/nio/CharBuffer
>>>>      java/nio/HeapCharBuffer
>>>>
>>>>    This approach creates a problem when the class sun.misc.Unsafe 
>>>> is retransformed.
>>>>    The Method* pointer to the old (redefined) method in the itable 
>>>> triggers an assert
>>>>    (see the hs_err log in the bug report).
>>>>    Coleen told me that a similar approach is going to be 
>>>> implemented for some vtable entries.
>>>>    Coleen, thanks for suggesting a better fix for this issue!
>>>>
>>>>    The fix is to replace the old Unsafe method in the itable/vtable 
>>>> with the latest method version.
>>>>
>>>>
>>>> Testing:
>>>>   In progress: nsk.jdi.testlist, JTREG java/lang/instrument tests
>>>>
>>>>
>>>> Thanks,
>>>> Serguei
>>>>
>>>
>>
>