RFR: 8259486: Replace PreserveExceptionMark with implementation for CautiouslyPreserveExceptionMark [v2]

[Coleen Phillimore]

On Mon, 11 Jan 2021 13:10:16 GMT, Coleen Phillimore <coleenp at 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.
>
> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix clear_pending_exception in fill_in_stack_trace.

src/hotspot/share/classfile/javaClasses.cpp line 2557:

> 2555:   PreserveExceptionMark pm(Thread::current()); // not necessarily JavaThread::active().
> 2556: 
> 2557:   JavaThread* thread = JavaThread::active();

This should NOT be JavaThread::active() since it's passed and used as TRAPS, ie, as the current thread for creating ResourceMark and throwing exceptions.  This is wrong.

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PR: https://git.openjdk.java.net/jdk/pull/2007