RFR: 8268164: Adopt cast notation for WorkerThread conversions

[Stefan Karlsson]

On Thu, 3 Jun 2021 11:59:35 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> > I wonder if it wouldn't be nicer to be able to write:
> > ```
> > WorkerThread::current()->id()
> > ```
> 
> That will cause a compiling error:
> 
> ```
> src/hotspot/share/gc/shared/referenceProcessor.cpp:933:35: error: no member named 'id' in 'Thread'
>     id = WorkerThread::current()->id();
>          ~~~~~~~~~~~~~~~~~~~~~~~  ^
> 1 error generated.
> ```
> 
> `WorkerThread` doesn't have a static `current()` method, so it will get the one from `Thread`, which returns a `Thread*`. However, `id()` is only defined for `WorkerThread`, not `Thread`.

Looks like you just called Thread::current() via WorkerThread. I mean that it would be nice if you could create a function that looked something like this:

static WorkerThread* WorkerThread::current() {
  return WorkerThread::cast(Thread::current());
}

-------------

PR: https://git.openjdk.java.net/jdk/pull/4334