RFR(S): 8061443: Whitebox get*VMFlag() methods fail with develop flags in product builds

[Tobias Hartmann]

On 23.10.2014 12:13, Staffan Larsen wrote:
> I don’t agree that locked flags are the same as debug flags. Perhaps two queries? One for constant flags and one for locked flags?

Okay, I added the methods 'isLockedVMFlag' and 'isConstantVMFlag' and adapted
the tests.

New webrev: http://cr.openjdk.java.net/~thartmann/8061443/webrev.03/

Thanks,
Tobias

> /Staffan
> 
> 
> On 23 okt 2014, at 12:02, Tobias Hartmann <Tobias.Hartmann at oracle.com> wrote:
> 
>> Hi Staffan,
>>
>> On 23.10.2014 11:29, Staffan Larsen wrote:
>>> This is better!
>>>
>>> But won’t the new WB_IsDebugVMFlag() return true for flags that don’t exist at all? 
>>
>> Of course, you are right. I fixed it and added a call to 'isDebugVMFlag' to
>> 'VmFlagTest.testWriteNegative' to check that it always returns false for
>> non-existing flags.
>>
>> New webrev: http://cr.openjdk.java.net/~thartmann/8061443/webrev.02/
>>
>> Thanks,
>> Tobias
>>
>>>
>>> /Staffan
>>>
>>>
>>> On 23 okt 2014, at 10:57, Tobias Hartmann <Tobias.Hartmann at oracle.com
>>> <mailto:Tobias.Hartmann at oracle.com>> wrote:
>>>
>>>> Vladimir, David, Staffan,
>>>>
>>>> thanks for the reviews.
>>>>
>>>> On 23.10.2014 09:06, Staffan Larsen wrote:
>>>>>
>>>>> On 23 okt 2014, at 04:35, David Holmes <david.holmes at oracle.com
>>>>> <mailto:david.holmes at oracle.com>> wrote:
>>>>>
>>>>>> On 23/10/2014 7:22 AM, Vladimir Kozlov wrote:
>>>>>>> getVMOption() specification does not say anything about product, locked
>>>>>>> or develop flags. "If a VM option of the given name does not exist" can
>>>>>>> interpreted different ways.
>>>>>>
>>>>>> Perhaps, but conceptually develop flags are not part of a product build and
>>>>>> by definition non-product flags are not part of a product build, so I think
>>>>>> the existing jmm code is quite right to exclude them and the new code should
>>>>>> do the same. It doesn't make sense to me to present someone with a list of
>>>>>> flags that can't actually be used.
>>>>>
>>>>> I agree with David here. Instead of changing the JMM API, you can add
>>>>> functionality to the WhiteBox API to get the value of non-product flags.
>>>>
>>>> I agree. I reverted the JMM changes and added a Whitebox API method
>>>> 'isDebugVMFlag' to check whether a flag is debug/notproduct.
>>>>
>>>> I changed the tests such that we only use JMM to verify the values returned by
>>>> the Whitebox API if the flag is accessible (i.e. is not a debug/notproduct flag
>>>> in a product build).
>>>>
>>>> New webrev: http://cr.openjdk.java.net/~thartmann/8061443/webrev.01/
>>>>
>>>> Thanks,
>>>> Tobias
>>>>
>>>>> /Staffan
>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>> David
>>>>>>
>>>>>>> http://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/HotSpotDiagnosticMXBean.html
>>>>>>>
>>>>>>>
>>>>>>> VMOption getVMOption(String name)
>>>>>>>
>>>>>>>   Returns a VMOption object for a VM option of the given name.
>>>>>>>
>>>>>>>   Returns:
>>>>>>>       a VMOption object for a VM option of the given name.
>>>>>>>   Throws:
>>>>>>>       NullPointerException - if name is null.
>>>>>>>       IllegalArgumentException - if a VM option of the given name
>>>>>>> does not exist.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Vladimir
>>>>>>>
>>>>>>> On 10/22/14 6:46 AM, Tobias Hartmann wrote:
>>>>>>>> Hi David,
>>>>>>>>
>>>>>>>> On 22.10.2014 14:33, David Holmes wrote:
>>>>>>>>> On 22/10/2014 6:48 PM, Tobias Hartmann wrote:
>>>>>>>>>> Hi David,
>>>>>>>>>>
>>>>>>>>>> On 22.10.2014 04:16, David Holmes wrote:
>>>>>>>>>>> Hi Tobias,
>>>>>>>>>>>
>>>>>>>>>>> On 21/10/2014 11:08 PM, Tobias Hartmann wrote:
>>>>>>>>>>>> Hi,
>>>>>>>>>>>>
>>>>>>>>>>>> please review the following patch.
>>>>>>>>>>>>
>>>>>>>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8061443
>>>>>>>>>>>> Webrev: http://cr.openjdk.java.net/~thartmann/8061443/webrev.00/
>>>>>>>>>>>>
>>>>>>>>>>>> Problem:
>>>>>>>>>>>> The Whitebox API methods get*VMFlag() fail with develop/notproduct
>>>>>>>>>>>> flags in
>>>>>>>>>>>> product builds.
>>>>>>>>>>>>
>>>>>>>>>>>> Solution:
>>>>>>>>>>>> The code is changed to invoke 'Flag::find_flag' with
>>>>>>>>>>>> allow_locked=true and
>>>>>>>>>>>> return_flag=true to return both locked and notproduct/develop
>>>>>>>>>>>> flags. I also
>>>>>>>>>>>> changed the JVM monitoring and management code 'jmm_GetVMGlobals()'.
>>>>>>>>>>>
>>>>>>>>>>> Why did you change the jmm code? You seemed to have changed its
>>>>>>>>>>> semantics -
>>>>>>>>>>> which may require a CCC request.
>>>>>>>>>>
>>>>>>>>>> I changed the jmm code because the whitebox tests use a JMM call to
>>>>>>>>>> verify the
>>>>>>>>>> return value (see 'VmFlagTest<T>.getVMOptionAsString()').
>>>>>>>>>>
>>>>>>>>>> Do you think a CCC request is necessary here?
>>>>>>>>>
>>>>>>>>> Depends what the jmm code is supposed to return - I don't know the
>>>>>>>>> spec. But
>>>>>>>>> changing the behaviour for the sake of a test without consideration
>>>>>>>>> of real
>>>>>>>>> users is not something that should be done lightly.
>>>>>>>>
>>>>>>>> I agree. I filed a CCC request and attached the link to the bug.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Tobias
>>>>>>>>
>>>>>>>>>
>>>>>>>>> David
>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Tobias
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> David
>>>>>>>>>>>
>>>>>>>>>>>> I adapted the existing tests to check for develop flags as well. I
>>>>>>>>>>>> noticed that
>>>>>>>>>>>> HotspotDiagnosticMXBean.getVMOption() fails with double flags and
>>>>>>>>>>>> filed
>>>>>>>>>>>> JDK-8061616 [1].
>>>>>>>>>>>>
>>>>>>>>>>>> Testing:
>>>>>>>>>>>> - New testcases
>>>>>>>>>>>> - JPRT
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Tobias
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> [1] https://bugs.openjdk.java.net/browse/JDK-8061616
>>>
>