[9] RFR (XS): 8155635: C2: opaque unsafe access triggers an assert

[Vladimir Kozlov]

Looks good. What actual alias type in such case?

Thanks,
Vladimir

On 5/5/16 11:48 AM, 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