RFR: 8274903: Zero: Support AsyncGetCallTrace

[Serguei Spitsyn]

On Thu, 7 Oct 2021 12:42:48 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> This is a Zero infrastructure improvement that makes Zero VM work with AsyncGetCallTrace, and by extension, async-profiler.
> 
> Zero is quite odd in stack management. The "real" stack actually contains the C++ Interpreter and the rest of VM code. The Java stack is reported through the usual "frame" mechanism the rest of VM uses to get the mapping from Template Interpreter, stub, and compiled code. So, to support Java-centric AsyncGetCallTrace, we t "only" need Zero to report the proper Java frames from its ZeroStack from the profiling/signal handlers. 
> 
> Additional testing:
>  - [x] Linux x86_64 Zero `serviceability/AsyncGetCallTrace` now pass
>  - [x] Linux x86_64 Zero works with `async-profiler`

Hi Aleksey,
Thank you for the update. It looks pretty good to me.
I've inlined a couple of minor comments.
Also, I hope, you will update the copyright years.
Thanks,
Serguei

src/hotspot/share/prims/forte.cpp line 348:

> 346:     return false;
> 347:   }
> 348: #endif

Could you, please, add some simple comments explaining each case at lines:  325, 329 and 336?

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

Marked as reviewed by sspitsyn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5848