[lworld] RFR: 8377451: [lworld] Add ValuePayload abstraction [v8]

[Coleen Phillimore]

On Fri, 13 Feb 2026 12:55:47 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> This commits does only what you say. https://github.com/openjdk/valhalla/pull/2068/changes/59c1fc2e7dedd079a61dced4401267dace7c642d However this still have to touch every line as each column is not wide enough to fit every entry, so when we now shift some by one and some by two alignment of all is required. 
>> 
>> @stefank thought, and I agree that if we have to touch every line anyways, let us just avoid this 4x64 grid and have one bytecode dispatch label per line, to not have to touch 64 lines in the future when making changes to one bytecode. (Someone might want to implement the fast bytecodes for zero in the future.)
>> 
>> I did push them as two separate commits so I can revert https://github.com/openjdk/valhalla/pull/2068/changes/342cd358eec59e1798ef62d03bbbd3a0e0f79d9d if you have really strong opinions on this. However I do think that the 4x64 is worse than the 1x256 solution.
>
> I actually look at this code periodically and don't really like scrolling down 256 lines to get to interesting parts.  This code doesn't change so the merge with valhalla would be zero if it was 4 bytecodes per line.  See if @shipilev  has a differing opinion.  Sorry for only commenting on the style nit but I found this jarring.

Actually I wonder if there's a performance benefit to this case label implementation anymore.  It was added when there was once a hope of replacing the template interpreter with this one.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/2068#discussion_r2804097218