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

[Vladimir Kozlov]

whitebox.cpp I don't why you need to split next lines:

+   {CC"isConstantVMFlag",      CC"(Ljava/lang/String;)Z",
+                                                       (void*)&WB_IsConstantVMFlag},
+   {CC"isLockedVMFlag",     CC"(Ljava/lang/String;)Z",
+                                                       (void*)&WB_IsLockedVMFlag},

VmFlagTest.java add line to the next comment:

// JMM cannot access debug flags in product builds or locked flags,
// use whitebox methods to get such flags value.

Otherwise seems correct.

Thanks,
Vladimir

On 10/23/14 4:15 AM, Tobias Hartmann wrote:
>
> 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
>>>>
>>