RFR (S): JDK-8164086: Checked JNI pending exception check should be cleared when returning to Java frame

[David Simms]

Updated webrev: http://cr.openjdk.java.net/~dsimms/8164086/webrev3/



On 06/09/16 01:20, David Holmes wrote:
> Hi David,
>
> On 5/09/2016 6:02 PM, David Simms wrote:
>> Hi David,
>>
>> I can make the checks silent, but the launcher itself produces warnings
>> from checked JNI (it's use of unchecked Java method invocations), and
>> this causes the test
>> (http://cr.openjdk.java.net/~dsimms/8164086/webrev2/hotspot/test/runtime/jni/checked/TestCheckedJniExceptionCheck.java.html) 
>>
>> to fail, with unchecked exception warnings popping up in the output.
>
> I've looked back at your original changes in this area but I'm still 
> not seeing exactly where the unchecked back-to-back JNI calls are 
> happening. For example NewPlatformString can return with an exception 
> pending, but will return NULL, and the calling code has checks for NULL.
>

LoadMainClass:

http://hg.openjdk.java.net/jdk9/hs/jdk/file/090cbd92c744/src/java.base/share/native/libjli/java.c#l1530

Calls "CallStaticObjectMethod" from "NewPlatformString", then on line 
1531 make another call "CallStaticObjectMethod".

No exception check is made. The Xcheck:jni code cannot interpreter the 
return value from JNI "Call<X>Method" functions, so it triggers the 
"unchecked" exception warning at line 1531.


>> But yeah, I could adjust the test the ignore any start-up warnings and
>> drop the changes to the launcher...
>
> Unless we can more clearly identify exactly where the launcher has a 
> problem I would prefer not to involve it in these changes. But I would 
> like to understand exactly why the launcher is triggering the check.
>

Dropped launcher changes, adjusted the test to ignore any previous warnings.

Cheers
/David Simms