RFR: JDK-8317799 : AIX PPC64: FFI symbol lookup doesn't find symbols

[Martin Doerr]

On Mon, 13 Nov 2023 11:47:52 GMT, suchismith1993 <duke at openjdk.org> wrote:

>>> There is not generic way of generating this. It needs a manual intervention and symbols are to be added on a need basis in future. Looks like a list to be maintained. I had tried adding comments to explain the list, but that causes build failures.
>> 
>> Would it be possible to paste the summary of the "instructions" to generate this? My initial reaction when seeing this PR is to wonder why it can't be generated at build time but from the discussion, it seems like it's a subset symbols, just the functions used by libjvm or is it all the native libraries?
>
>> > There is not generic way of generating this. It needs a manual intervention and symbols are to be added on a need basis in future. Looks like a list to be maintained. I had tried adding comments to explain the list, but that causes build failures.
>> 
>> Would it be possible to paste the summary of the "instructions" to generate this? My initial reaction when seeing this PR is to wonder why it can't be generated at build time but from the discussion, it seems like it's a subset symbols, just the functions used by libjvm or is it all the native libraries?
> 
> I just did a nm command and did a grep of " T " . That way i got all the symbols for math libraries. There were additional parsing instructions to remove the first column and remove periods at beginning.
> 
> Then we had to remove certain symbols that are dependent on DFP symbols and xlc17 doesn't support them yet, So we had to trim down the list further, which is why it now becomes a list to be maintained.

@suchismith1993: Can you add your explanations to the description at the top of this PR, please?
I think restricting symbols to the ones from C standard makes sense.
@magicus: We need a solution for JDK22 since the FFI including symbol lookup has become a required interface. RDP1 is coming closer and I don't see a better solution coming soon enough. Can we go ahead with a symbol list file for JDK22? Where should it reside if not in make/data/hotspot-symbols?

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PR Comment: https://git.openjdk.org/jdk/pull/16414#issuecomment-1816276842