On Mon, 11 Jan 2021 01:13:25 GMT, David Holmes <dhol...@openjdk.org> wrote:
>> See CR for details. This is a hopefully simple cleanup. I didn't try to
>> reason about removing any of these except an obvious call (if you look above
>> the patch in thread.cpp).
>> Tested with tier1-3.
>
> src/hotspot/share/runtime/thread.cpp line 1867:
>
>> 1865: // Call method Thread.dispatchUncaughtException().
>> 1866: Klass* thread_klass = SystemDictionary::Thread_klass();
>> 1867: JavaValue result(T_VOID);
>
> I think I agree that this is redundant. Seems to be a leftover from something
> else.
Yes. Look above it. It clears the exception mark so there's never an
exception pending. strange we didn't clean this out sometime between 1.2 and
now.
> src/hotspot/share/classfile/javaClasses.cpp line 2528:
>
>> 2526: if (total_count == 0) {
>> 2527: // The top frame will be hidden from the stack trace.
>> 2528: bt.set_has_hidden_top_frame();
>
> To be clear: no exception can become pending due to this call, so no need for
> CHECK.
Correct. I think it used to allocate an object so could throw OOM but that was
changed.
> src/hotspot/share/classfile/javaClasses.cpp line 2556:
>
>> 2554:
>> 2555: JavaThread* thread = JavaThread::active();
>> 2556: PreserveExceptionMark pm(thread);
>
> The result of JavaThread::active() is not necessarily the current thread. So
> either the new code is wrong or else we should just be using
> JavaThread::current()
My first iteration of this change knew there was a difference then I cleaned it
up. I'll restore the Thread::current() in the PEM constructor.
-------------
PR: https://git.openjdk.java.net/jdk/pull/2007
