Request for review JDK-8185591 guarantee(_byte_map[_guard_index] == last_card) failed: card table guard has been modified

[dean.long at oracle.com]

For arm you can use cbz_32.

dl


On 11/21/17 2:18 PM, Alexander Harlap wrote:
> Please review change for JDK-8185591 
> <https://bugs.openjdk.java.net/browse/JDK-8185591> - 
> guarantee(_byte_map[_guard_index] == last_card) failed: card table 
> guard has been modified
>
> Change is located at 
> http://cr.openjdk.java.net/~aharlap/8185591/webrev.01/
>
> Problem was in mishandling zero count in code generated by 
> gen_write_ref_array_post_barrier().
>
> Code is machine specific. Suggested fix for arm, sparc and x86_64.
>
> No changes are  required for x86_32 - case zero count already is 
> handled properly ( same as for s390 and ppc).
>
> Aarch64 code have same problem as arm, sparc and x86_64, but I did not 
> include this platform in suggested changeset.
>
> I attached possiible change for aarch64 stubGenerator_aarch64.cpp.diff
>
> Testing was done with JPRT.
>
> Thank you,
>
> Alex
>