RFR: 8268368: Adopt cast notation for JavaThread conversions [v2]

[Guoxiong Li]

On Tue, 22 Jun 2021 01:59:17 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fix incorrect use of the method cast
>
> Hi Guoxiong,
> 
> Thanks for picking up this enhancement request.
> 
> I wasn't sure if this would be worth the churn/disruption to the source code, but I think it is ok and preferable to use the cast notation.
> 
> The changes look good except for one mistake flagged below.
> 
> Note you need at least two reviewers before integrating this.
> 
> Thanks,
> David

@dholmes-ora Thanks for your review. I updated the code just now.

I am surprised that the `tier1` (locally and the `Pre-submit tests`) can't find the mistake you pointed out.
Maybe we can improve the `tier1` or the `Pre-submit tests` in the future.

> src/hotspot/share/gc/z/zFuture.inline.hpp line 49:
> 
>> 47:   // Wait for notification
>> 48:   Thread* const thread = Thread::current();
>> 49:   if (JavaThread::cast(thread)) {
> 
> This is wrong - we still need the is_Java_thread() query; and cast is not a boolean operator.

Fixed. It's a wrong use of the method `cast`. Thanks for finding it. I re-read my patch to avoid the similar mistake.

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PR: https://git.openjdk.java.net/jdk/pull/4546