RFR(7u) 8046233: VerifyError on backward branch

[Coleen Phillimore]

Good.
Coleen

On 8/29/14, 11:56 AM, harold seigel wrote:
> Hi Coleen,
>
> Thanks for the review.  I changed the name to 
> "has_nonmatching_new_object", and posted a new webrev containing the 
> name change: http://cr.openjdk.java.net/~hseigel/bug_8046233_7.2/
>
> Thanks, Harold
>
> On 8/29/2014 11:23 AM, Coleen Phillimore wrote:
>>
>> Harold,  This looks good.  I agree with Karen's request for a name 
>> change; either of her suggestions makes sense to me.
>>
>> Thanks,
>> Coleen
>>
>> On 8/27/14, 11:42 AM, harold seigel wrote:
>>> Hi Karen,
>>>
>>> I haven't checked this in.  You're the first reviewer.
>>>
>>> I like  "has_nonmatching_new_object".  I'll change it to that.
>>>
>>> Thanks!
>>> Harold
>>>
>>> On 8/27/2014 11:30 AM, Karen Kinnear wrote:
>>>> Harold,
>>>>
>>>> Code fix looks good.
>>>>
>>>> If you haven't already checked this in - would you mind renaming 
>>>> "has_unique_new_object" to
>>>> something like "has_nonmatching_uninit_object" or 
>>>> "has_nonmatching_new_object"? If that makes sense
>>>> to you.
>>>>
>>>> thanks,
>>>> Karen
>>>>
>>>> On Aug 22, 2014, at 10:47 AM, harold seigel wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> Please review this small fix for bug 8046233 for JDK-7u.
>>>>>
>>>>> Section 4.10.2.4 
>>>>> <http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.10.2.4> 
>>>>> of the JVM-7 Spec says:
>>>>>
>>>>>    A valid instruction sequence must not have an uninitialized object
>>>>>    on the operand stack or in a local variable at the target of a
>>>>>    backwards branch if the special type of the uninitialized 
>>>>> object is
>>>>>    merged with a special type other than itself ...
>>>>>
>>>>> Currently, the split verifier does not allow any backward branches 
>>>>> into a block containing an uninitialized object. This fix allows 
>>>>> such backward branches if the originating block contains an 
>>>>> uninitialized object of the same special type.
>>>>>
>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8046233
>>>>> Open webrev: http://cr.openjdk.java.net/~hseigel/bug_8046233_7/
>>>>>
>>>>> The fix was tested with the JCK lang, vm, and api/java_lang tests, 
>>>>> the JTREG hotspot tests, and tests that reproduced the problem. 
>>>>> With this fix, the tests that reproduce the problem get the same 
>>>>> result with both the old and the split verifier.
>>>>>
>>>>> This bug has already been fixed in JDK-8u and JDK-9.  But, a 
>>>>> straight back-port to JDK-7u could not be done because the JVM-8 
>>>>> Spec differs from the JVM-7 Spec for this case.
>>>>>
>>>>> Thanks, Harold
>>>
>>
>