RFR (S): 8230395: Code checks for NULL value returned from NEW_C_HEAP_ARRAY which can not happen

[Leo Korinth]

On 19/09/2019 07:57, David Holmes wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8230395
> webrev: http://cr.openjdk.java.net/~dholmes/8230395/webrev/
> 
> First, thanks to Leo for going through and finding the places that 
> needed to be fixed. I didn't go looking for others.

I tried to find all places for NEW_C_HEAP_ARRAY. Thanks for not only 
fixing the problematic use but also doing some cleanup around it! It was 
not obvious for me where to remove the check and where to add 
RETURN_NULL, so thank you for doing this.

> 
> For the most part I have deleted the NULL checks. A few notes:
> 
> - changed to NEW_C_HEAP_ARRAY_RETURN_NULL in a couple of places where it 
> was more consistent with the general recoverability approach of the code 
> in question (and did the opposite change in one place)
> - for the "perf" changes I also noticed that we were checking for NULL 
> after doing "new SomeCHeapObj()" which also cannot return NULL, so 
> removed those NULL checks too
> - the JVMCI thread counter changes became a bit more extensive due to 
> the fact a boolean method could now only every return true. So it was 
> changed to void and that had to filter all the way back up to the JVMCI 
> Java API. The JVMCI/Graal folk need to approve this
> 
> Testing: tier 1-3 sanity tests (in progress)
> 
> Thanks,
> David

This change looks good to me (I am not a reviewer).

Thanks,
Leo