[lworld+vector] RFR: 8304310: Initial compilers and runtime handling for multifield backed vectors. [v13]

[Vladimir Ivanov]

On Sat, 6 May 2023 00:10:38 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Handling multifield access through Unsafe.get API, some more cleanups.
>
> src/hotspot/share/runtime/deoptimization.cpp line 1146:
> 
>> 1144:         if (EnableVectorSupport && VectorSupport::is_vector(ik)) {
>> 1145:           obj = VectorSupport::allocate_vector(ik, fr, reg_map, sv, THREAD);
>> 1146:         } else if (EnableVectorSupport && VectorSupport::is_vector_payload_mf(ik)) {
> 
> Why do you need to handle both cases now? Anything special needed for `VectorSupport::is_vector()` case?

Another question: is there a lurking problem in the original implementation? Can a backing array leak into debug info, so reallocation has to handle it? I believe it's not the case since vector scalarization logic relies on typed vector box to pass type information, but want to double-check with you.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/833#discussion_r1186565966