[9] RFR (XS): 8155781: C2: opaque unsafe access triggers an assert

[Vladimir Ivanov]

Thanks, fixed (updated in place).

Best regards,
Vladimir Ivanov

On 7/21/16 7:32 PM, Leonid Mesnik wrote:
> Vladimir
>
> I think that test should fail if it is executed on the client/minimal
> without additional '-XX:+IgnoreUnrecognizedVMOptions'.  Could you please
> add corresponding '@requires' tag of '-XX:+IgnoreUnrecognizedVMOptions'
> if you
>
> think that it would be useful to run it on the jdk build without C2.
>
> Leonid
>
>
> On 21.07.2016 16:49, Vladimir Ivanov wrote:
>> Updated version:
>>   http://cr.openjdk.java.net/~vlivanov/8155781/webrev.01/
>>
>> I haven't pushed the initial fix yet, since I started looking into
>> removing the checks. Unfortunately, recent migration of j.u.c to
>> VarHandles made the problematic code shape much more frequent. I was
>> asked to push the fix directly into jdk9/dev to reduce the noise in
>> test results.
>>
>> It turned out LibraryCallKit::inline_unsafe_load_store() doesn't need
>> the check (no special cases for "wide" accesses), so I removed it.
>>
>> I'll address the check in LibraryCallKit::inline_unsafe_access()
>> separately (filed JDK-8162101), since I have to push it into hs-comp
>> to avoid merge conflicts during hs -> dev integration.
>>
>> Testing: JPRT (-testset hotspot), RBT (hs-tier0-comp; in progress).
>>
>> Thanks!
>>
>> Best regards,
>> Vladimir Ivanov
>>
>> [1] https://bugs.openjdk.java.net/browse/JDK-8162101
>>
>> On 5/5/16 9:48 PM, Vladimir Ivanov wrote:
>>> http://cr.openjdk.java.net/~vlivanov/8155781/webrev.00/
>>> https://bugs.openjdk.java.net/browse/JDK-8155781
>>>
>>> The following code hits an assert in
>>> LibraryCallKit::inline_unsafe_access() during compilation of the
>>> following code:
>>>
>>>     int test(Object o) {
>>>         return UNSAFE.getInt(o, F_OFFSET);
>>>     }
>>>
>>> It baffles the compiler since such shape can be used to access both
>>> on-heap and off-heap memory (due to double-register addressing mode).
>>>
>>> The proposed fix is to convert the asserts into guards which revert to
>>> native calls in such cases.
>>>
>>> Testing: JPRT, RBT (hs-tier0-comp).
>>>
>>> Thanks!
>>>
>>> Best regards,
>>> Vladimir Ivanov
>