RFR: Fix off-by-one error when verifying object registrations [v3]

[William Kemper]

On Fri, 2 Sep 2022 18:03:30 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> William Kemper has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove unnecessary allocate/free checks
>
> Just some drive-by-comments, I'm not a shenandoah developer.
> 
> Note that the trailing information after os::malloc/NEW_C_HEAP_ARRAY confusing your reader are canaries we set in NMT to catch overflow errors.
> 
> Cheers, Thomas

Appreciate you stopping by @tstuefe , thanks for the review.

> src/hotspot/share/gc/shenandoah/shenandoahScanRemembered.hpp line 555:
> 
>> 553: 
>> 554:   ~ShenandoahCardCluster() {
>> 555:     if (object_starts != nullptr) {
> 
> Strictly speaking also not needed, since free(NULL) is a noop (also os::free, FREE_C_HEAP_ARRAY, etc)

Thank you, I've cleaned this up.

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PR: https://git.openjdk.org/shenandoah/pull/160