Fwd: RFR (XXS): JDK-8046668 : Excessive checked JNI warnings from Java startup

[David Simms]

Hi David,

You mean the "jni.cpp:jni_functions()" which returns the checked 
functions (with -Xcheck:jni flag set) in the "JNINativeInterface" struct 
of function pointers ?

I recently add these extra warnings, if a function is call without 
previously checking for exceptions.

As stated in JDK-8046668 warnings for not checking functions that throw 
ArrayOutOfBoundException aren't very useful, since most code makes 
length and offset checks before calling, see the bug for an example. " 
set_pending_jni_exception_check" arms the need for an exception check 
before calling further JNI functions.

https://bugs.openjdk.java.net/browse/JDK-8046668

Hope this was the answer you wanted
/Mr. Simms

On 2014-07-11 09:17, David Holmes wrote:
> Hi David,
>
> Sorry I'm having trouble connecting the dots here. How do we get from 
> the JNI entry points defined in jni.cpp these "checked "entry points 
> in jniCheck.cpp ? I can't reconcile how the warnings can be removed 
> when some of these functions are used.
>
> Thanks,
> David H.
>
> On 11/07/2014 4:19 PM, David Simms wrote:
>>
>> Thanks for the review Harold and Lois,
>>
>> I've updated the patch with your comments:
>>
>> http://cr.openjdk.java.net/~dsimms/8046668/
>>
>> Thanks
>> /David Simms
>>
>> On 2014-07-10 14:16, Lois Foltan wrote:
>>>
>>> Hi David,
>>>
>>> Looks good, given the number of exeception_checks you removed I agree
>>> with your description of pedantic :-) !
>>>
>>> src/share/vm/prims/jniCheck.cpp
>>>   - subjective comment on my part, I find the name of the new method a
>>> bit long, would
>>>     you consider renaming to "add_planned_handle_capacity"?
>>>  -  Also, would you consider within the function just calling
>>> set_planned_capacity(capacity +
>>>     handles->get_number_of_live_handles() +
>>> CHECK_JNI_LOCAL_REF_CAP_WARN_THRESHOLD)?
>>>     Modifying a parameter that was passed in by value can be confusing.
>>>
>>> Overall, though I am good with the change, reviewed.
>>>
>>> Thanks,
>>> Lois
>>>
>>>
>>>>
>>>> -------- Original Message --------
>>>> Subject:     RFR (XXS): JDK-8046668 : Excessive checked JNI warnings
>>>> from Java startup
>>>> Date:     Tue, 17 Jun 2014 10:26:10 +0200
>>>> From:     David Simms <david.simms at oracle.com>
>>>> To:     hotspot-runtime-dev at openjdk.java.net
>>>> <hotspot-runtime-dev at openjdk.java.net>
>>>>
>>>>
>>>>
>>>> Hello,
>>>>
>>>> I have fix for the following bug:
>>>>
>>>>      JDK-8046668 : "Excessive checked JNI warnings from Java startup"
>>>>
>>>>      https://bugs.openjdk.java.net/browse/JDK-8046668
>>>>
>>>> Web review:
>>>>
>>>>      http://cr.openjdk.java.net/~dsimms/8046668/
>>>>
>>>> This fix remove some of the pedantic JNI exception checks warnings for
>>>> functions that throw ArrayOutOfBoundException. It was found almost all
>>>> code checks array length, making exception checking code 
>>>> meaningless for
>>>> these function.
>>>>
>>>> Also fix a small bug for the excessive local reference warnings 
>>>> (always
>>>> add to current number of live handles).
>>>>
>>>> Testing:
>>>>
>>>>      All platforms:
>>>>      - JPRT
>>>>      - VM testbase: "  vm.quick.testlist
>>>> vm.parallel_class_loading.testlist vm.regression.testlist
>>>> vm.runtime.testlist"
>>>>      - JTREG: JDK & JVM
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>