RFR: 8324834: Use _LARGE_FILES on AIX

[Matthias Baesken]

On Mon, 29 Jan 2024 11:44:34 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> In the same spirit as [JDK-8318696](https://bugs.openjdk.org/browse/JDK-8318696), we should adapt the AIX-specific code in hotspot so it uses the well-defined posix `<foo>` functions, instead of `<foo>64`. By setting the define _LARGE_FILES, this will make `<foo>` behave as `<foo>64`, just as _FILE_OFFSET_BITS=64 does on gcc. (Reference: https://www.ibm.com/docs/en/aix/7.1?topic=volumes-writing-programs-that-access-large-files)
> 
> In theory, it should not even be necessary to set this, since we only compile for 64-bit AIX platforms, and this is only relevant on 32-bit platforms. But let's add the define anyway, for good measure. It shows at least that we have thought about the matter. :-)
> 
> I have not been able to test this on AIX. I hope someone with AIX access can take this for a spin.
> 
> The reason I'm doing this is for [JDK-8324539](https://bugs.openjdk.org/browse/JDK-8324539). After both these bugs are fixed, there will be no more `<foo>64` function calls in the code base.

> I believe this has missed 2 callsites in os_posix.cpp, which recently swapped to the 64 suffixed variant that is controlled the AIX_ONLY macro #17587

Yes the  2 changes 'overlapped' .

Using the '_LARGE_FILES' should be okay, I checked this in a small example in the binary and it showed the the 64bit/large file function was used.

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PR Comment: https://git.openjdk.org/jdk/pull/17611#issuecomment-1914669910
PR Comment: https://git.openjdk.org/jdk/pull/17611#issuecomment-1914672408