RFR: Load coops base shift from AOTRuntimeConstants in AOT code [v2]

[Vladimir Kozlov]

On Wed, 11 Sep 2024 14:45:58 GMT, Andrew Dinn <adinn at openjdk.org> wrote:

>> This PR modifies AOT compiled method code to load compressed oops base and shift constants via the AOTRuntimeConstants area rather than encode them as immediates. It also unlatches the currently forced setting of UseCompatibleCompressedOops, allowing the heap to be allocated wherever it will fit.
>
> Andrew Dinn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   only check UseCompatibleCompressedOops on 64 bit builds

Sorry, I am not sure about these changes any more vs enabling unconditionally `UseCompatibleCompressedOops`.
You will always use these loads, even for simplest "Unscaled" case. The performance will be much worse than using enforced constant shift and base.

Did you run any performance testing?

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PR Comment: https://git.openjdk.org/leyden/pull/20#issuecomment-2347229377