[lworld] RFR: 8348606: [lworld] Substitutability test may perform heap allocations [v2]

[Chen Liang]

On Thu, 13 Feb 2025 01:17:07 GMT, Chen Liang <liach at openjdk.org> wrote:

>> Update substitutability test to use MethodHandles that access independent primitive/pointer instead heap reallocated copies of inlined values with an object header. Need long-term solution for user MethodHandle that accesses nested values in the future; hope the intrinsics can help in the future.
>> 
>> Testing: test/jdk/valhalla and test/hotspot/jtreg/*/valhalla, tier 1-3 tests running.
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix redundant debug and failing IO test

Hmm, @fparain recommends this access pattern for me...

Marking this ready - @TobiHartmann recommends me to integrate and C2 to subsequently fix up. This can fix JDK-8354122.

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PR Comment: https://git.openjdk.org/valhalla/pull/1364#issuecomment-2657028106
PR Comment: https://git.openjdk.org/valhalla/pull/1364#issuecomment-2789125586