RFR: 8263125: During deoptimization vectors should reassign scalarized payload after all objects are reallocated. [v2]

[Reingruber, Richard]

I see. Thanks again for answering my questions.

Richard.

-----Original Message-----
From: hotspot-dev <hotspot-dev-retn at openjdk.java.net> On Behalf Of Vladimir Ivanov
Sent: Freitag, 12. März 2021 12:33
To: hotspot-dev at openjdk.java.net; hotspot-compiler-dev at openjdk.java.net
Subject: Re: RFR: 8263125: During deoptimization vectors should reassign scalarized payload after all objects are reallocated. [v2]

On Fri, 12 Mar 2021 10:54:44 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

> And can't the payload for deoptimization be represented as a scalarized array in that case too? Maybe not because of the special handling a VectorMask requires.

Vector is special in a very similar way: debug info contains only vector value location. Custom logic is needed to turn it into scalarized array representation. And then there's still a step required to allocate the corresponding typed vector box which wraps the payload.

I'm not saying it is not possible to represent current on-heap shape solely in debug info, but it would require significant refactorings/enhancements of existing machinery. And would complicate possible changes of the on-heap vector/mask shape. It is not something "cut in stone" and can evolve over time.

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PR: https://git.openjdk.java.net/jdk/pull/2924