RFR: 8238761: Asynchronous handshakes [v5]

[Robbin Ehn]

On Wed, 23 Sep 2020 02:40:31 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Robbin Ehn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update after Coleen
>
> src/hotspot/share/runtime/handshake.hpp line 45:
> 
>> 43: // a single target/direct handshake or not, by the JavaThread that requested the
>> 44: // handshake or the VMThread respectively.
>> 45: class HandshakeClosure : public ThreadClosure, public CHeapObj<mtThread> {
> 
> Is use of multiple inheritance allowed within hotspot code?

There is other 'sane' way to 'implement an interface' and being heap allocated.
We have a few like:
class DefaultICProtectionBehaviour: public CompiledICProtectionBehaviour, public CHeapObj<mtInternal>
class AOTCompiledMethod : public CompiledMethod, public CHeapObj<mtCode>
template <MEMFLAGS F> class TaskQueueSetSuperImpl: public CHeapObj<F>, public TaskQueueSetSuper

So the 'rule' about multiple inheritance is in conflict with not using new/delete operator without using CHeapObj.

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PR: https://git.openjdk.java.net/jdk/pull/151