RFR(S): 8216376: [PPC64] Possibly unreliable stack frame resizing in template interpreter

[Gustavo Romero]

Hi Martin,

On 01/08/2019 03:43 PM, Doerr, Martin wrote:
> we recently noticed stack corruption while testing JDK-8216060. The issue was not directly in the new code, but it didn’t work with the current handling of the interpreter stack frames which is very error-prone at a few places. 
> I’d like to improve these places. At least one of them even seems to be unreliable in the current implementation.
> Bug with some more background information:
> 
> https://bugs.openjdk.java.net/browse/JDK-8216376
> 
> My proposal to fix it:
> http://cr.openjdk.java.net/~mdoerr/8216376_PPC64_frame_resizing/webrev.00/ <http://cr.openjdk.java.net/%7Emdoerr/8216376_PPC64_frame_resizing/webrev.00/>

I've tested this change with JDK-8216060 on top of it for both release and
fastdebug builds and all tests passed fine.

To the best of my knowledge it looks correct and I think that restoring the
SP using resize_frame_absolute after the generated code looks more
consistent than the SP cut back before it and even makes the code easier to
follow/understand.

Thank you.

Best regards,
Gustavo