[Bug bootstrap/52623] 4.7.0-RC-20120314: bootstrap failure on AIX due to multilib and using C++ in post-stage1

["michael.haubenwallner at salomon dot at" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52623

--- Comment #15 from Michael Haubenwallner <michael.haubenwallner at salomon dot at> 2012-03-28 08:21:37 UTC ---
(In reply to comment #14)
> > Do you see any technical issue why Import
> > Files cannot be used this way for filename-based versioning over the
> > traditional onefile-membername-based versioning?
> 
> I think that import files can be used the way you suggest.

Ok, thank you!

> I am not sure I understand why you write that libNAME.so is broken.  AIX can
> search for a bare shared object named libNAME.so.

It isn't broken in a technical sense from AIX' point of view,
it is broken in the package manager's point of view, not allowing for /any/
kind of versioning at all (neither via filename nor via archive member with
F_LOADONLY flag), as well as breaking multilib.

> Also, I still believe that your "Linux" solution will require linking with
> -brtl or -bsvr4.

Yes, and the main (because technical) reason is to keep static linking
possible.

This also is the reason I've named the commandline switch "*able-aix-svr4" for
now, but I don't have a hard opinion here, because
--disable-static _would_ allow (administrative-wise) for import files even
without -brtl/-bsvr4 (easiest via symlink libNAME.a -> libNAME.so.1).

As the name "aix-svr4" implies runtime linking, maybe "aix-soname" is more
suitable...

So - what I'm still unsure is:
*) how far to go with disable-static (symlink libNAME.a->libNAME.so.1),
   maybe upon aix-svr4=compat only?
*) which name and values for the configure-switch are as obvious as possible:
   1 : --enable-aix-svr4=[no | compat | yes]
   1l: --enable-aix-svr4=[no | yes | only]           # less forceful
   2 : --enable-aix-soname=[no | compat | yes]
   2l: --enable-aix-soname=[no | yes | only]         # less forceful
   3 : --with-aix-soname=[aix,no | both | svr4,yes]
   3l: --with-aix-soname=[aix,no | both,yes | svr4]  # less forceful

Where "less forceful" means to take 'yes' to provide both (A)ix+(L)inux,
needing 'only' to drop (A)ix,
while the others take 'yes' to provide (L)inux _only_, needing 'compat' or
'both' to provide (A)ix too.

Also, I'd like to _allow_ for package /maintainers/ to set either 'both' or
'only' (whichever name the values will have) as default value via LT_INIT
(usually upon some API/SONAME bump), while still allowing for package
/managers/ to override.

Using above names, this would be:
                for (A)ix+(L)inux                   for (L)inux only
(1 )  LT_INIT([ aix-svr4=compat   ])      LT_INIT([ aix-svr4        ])
(1l)  LT_INIT([ aix-svr4          ])      LT_INIT([ aix-svr4=only   ])
(2 )  LT_INIT([ aix-soname=compat ])      LT_INIT([ aix-soname      ])
(2l)  LT_INIT([ aix-soname        ])      LT_INIT([ aix-soname=only ])
(3 )  LT_INIT([ aix-soname=both   ])      LT_INIT([ aix-soname      ])
(3l)  LT_INIT([ aix-soname        ])      LT_INIT([ aix-soname=svr4 ])

More/better ideas?

Thank you!