Re: Pass -G to IBM C/C++ compiler, not -Wl,-G

[Ralf Wildenhues]

Hi Albert,

* Albert Chin wrote on Mon, Dec 13, 2004 at 09:00:04AM CET:
> The IBM C/C++ compilers grok -G.

I think a longer comment on this is in order, as what happens
is subtly different between `$CC -G' and `$LD -G'.

Cf. IBM docs SG245674, e.g. at
http://www.redbooks.ibm.com/redbooks/SG245674/wwhelp/wwhimpl/js/html/wwhelp.htm
it even says in chapter 2.5.1 (Creating run-time linking shared objects):

| Note: Compiler drivers also have the -G option. Do not use the compiler -G
| option to create run-time linking shared objects from object files.

In one case, the undefined symbol will be bound to the special module
called `..', which means it will be resolved by the runtime-linker.  In
the other case (linking with $CC), I think the linker will not know
where to resolve this, but I'm not sure (have not tested).  So, I don't
know whether your patch is the right thing to do, and will need to be
convinced (but I also don't know whether what we did before your patch
was the right thing).  It'd be great if you could or anyone else could
look into this.

Your other patch regarding AIX/gcc/-G is fine and will be assimilated.

Regards,
Ralf

> 2004-12-13  Albert Chin-A-Young  <address@hidden>
> 
>       * libtool.m4: The IBM C/C++ compilers grok -G.