RFR: 8278479: RunThese test failure with +UseHeavyMonitors and +VerifyHeavyMonitors

[Coleen Phillimore]

On Thu, 30 Jun 2022 22:05:14 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> This change adds a null check before calling into Runtime1::monitorenter when -XX:+UseHeavyMonitors is set. There's a null check in the C2 and interpreter code before calling the runtime function but not C1.
> 
> Tested with tier1-7 (a little of 8) and built on most non-oracle platforms as well.

Thanks Vladimir and Dan for the quick reviews.
I ran all of the tiers with UseHeavyMonitors on, except I stopped the long running tests in tier8 because they would have failed right away if it was wrong.
The test for NullPointerExceptionMessage directly exercises this code with the options.
RunThese didn't reproduce this bug locally or with several non-local runs but the stack was the same as the NPE test.

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PR: https://git.openjdk.org/jdk/pull/9339