Re: Problems with AIX4 Compiler

[Tim Mooney]

In regard to: Re: Problems with AIX4 Compiler, Erik Lindahl said (at...:

>It's actually much easier; I've never seen a system where mpcc is a
>separate
>compiler. It's essentially always a scripts that replaces
>
>mpcc prog.c
>
>with
>
>cc -I<path to mpi include> -L<path to mpi libs> prog.c -lmpi

Ok, makes sense.

>The only thing that breaks this on sp2/aix is that the -blibpath option
>removes the hardcoding of <path to mpi libs>. The executables need
>this, since they use dynamic linking per default (an environment
>variable is used to decide which communication libraries should be
>linked at runtime).
>
>So, I have a patch for this, but it would mean removing the -blibpath
>option and relying on hardcoding of the -L flags instead, like on aix
>version 3.  The question is, would you find that acceptable from a
>security point of view?

:-)  I'm just a minor contributor to GNU software, so I'm hardly in a
position to be making any decisions on this issue.  Gary, Alexandre, and
crew are the ones to make the final decision about how to support this.

Removing the libpath exposes the people running MPI programs to some
risk, but it might very well be viewed an acceptable/minimal risk.  I
don't have access to MPI on AIX, so I have no way to help you try minimize
the risk.

I do have a question though.  Would it be possible to programmatically
determine what `-L' component(s) mpcc is adding in for the user?  For
example, if you have a very simple test program in conftest.c :

int main(int argc, char *argv[])
{
}

and you compile that with

        mpcc conftest.c

and you run `dump -H' on the resulting executable, does the path in
the Import File Strings tell you the (MPI-specific) directories that
were automatically added to the libpath, because of the `-L's?

If so, it may be possible to keep the `-blibpath' options, but automatically
include all MPI-specific directories when the mpcc compiler is being used.

If it's possible but turns out to be a lot of work to do this, it may
not be worth the risk.  That's something someone else needs to decide,
though.

Tim