[Python-Dev] AIX to stable, what does that take? (original) (raw)

Michael Haubenwallner michael.haubenwallner at ssi-schaefer.com
Fri Oct 5 10:15:29 EDT 2018

Hi Michael,

being on a similar road with Gentoo Prefix, I really do appreciate your AIX related work!

However, for two (not so minor) topics I've got a little different experience, which I think should be mentioned here for completion:

On 10/04/2018 11:13 AM, Michael Felt wrote:

On 10/4/2018 10:30 AM, INADA Naoki wrote:

Hello,

First of all, congratulations on passing all test on AIX.

As a one of core developer, I don't know anything about AIX. If my change breaks AIX build, I can't investigate what's happened.

So I think we need following in devguide: * Brief description about AIX, from developer's point of view. This I might be able to do. Bullet form:

... I build everything myself, using xlc (gcc introduces the need for a GNU RTE, e.g., glibc).

Using gcc does not require to use glibc or even GNU binutils at all. Except for gcc's own runtime libraries, there's no need for a GNU RTE. In fact, in Gentoo Prefix I do use gcc as the compiler, configured to use AIX provided binutils (as, ld, nm, ...), with AIX libc as RTE.

* finally, a bit deeper: while the AIX linker loader supports svr4 shared libraries (it is the data, not the file name) it also supports having multiple shared libraries in a classic archive. So, rather that .../lib/libxxx.so and .../lib64/libxxx.so AIX prefers .../lib/libxxx.a with two so-called members, with same or different names. The one found is not it's name, but the symbol name and size of the ABI (32-bit or 64-bit)

While this all is true, having multiple versions of one shared library in one single file is a PITA for package managers - both human or software.

But fortunately, the AIX linker does support so called "Import Files", allowing for filename based shared library versioning like on Linux, while still allowing for both ABIs in a single library archive file.

For example, libtool provides the --with-aix-soname={aix|svr4|both} configure flag since libtool-2.4.4. Although the default will stay at 'aix' here, in Gentoo Prefix I do use 'svr4' only. This actually is a package manager's decision, ideally for all depending packages. As gcc does use libtool, for more information please refer to https://gcc.gnu.org/install/configure.html#WithAixSoname But note that "Import Files" should work with xlc as well.

Thanks! /haubi/

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