itaps-parallel Fortran name mangling issues

[Mark Miller]

On Wed, 2008-11-12 at 16:53 -0500, Onkar Sahni wrote:
> > The FC_FUNC macro winds up getting defined by something; Autoconf's
> configure script does some work to define it. Or, like Onkar suggests,
> you can define some logic ahead of time to set whatever FC_FUNC does
> using logic like so...
> >
> > #ifdef AIX
> > #define FC_FUNC(lowFunc,UPfunc) _lowFunc
> > #elif GFORTRAN
> > #define FC_FUNC(lowFunc,UPfunc) UPfunc
> > #elif ...
> > ..
> > .
> 
>   So here is my question (basically what I was trying to ask in tele-con)
> which may or may not be possible:
> 
>   Can "#define FC_FUNC............" be generated in a central place during
> the process to install and build itaps softwares (before building any

I don't think it can because its definition depends on the name mangling
properties of the fortran compiler being used at time of (configuration)
compilation. Yes, the number of possible definitions for FC_FUNC is
finite, but know which it should be set to for a given compiler (and
what to use in the way of a detecting that) varies from compiler to
compiler. The BEST you can achieve is to identify what FC_FUNC should be
identified for common cases or cases that you know of so that it doesn't
need to be re-computed with each configure/compile.

> implementation/library or service). This would be an extra configure
> step in say /usr/local/itaps/headers (central location where all headers
> sit along with probably configure stuff) and this step would just
> generate a new header file say "itaps_fc_func.h".


> Say if one uses gfortran then the header file generated in "central" place
> (as an extra step using configure in "central" place) will contain
> following lines and every service and implementation simply use it.
> 
>   #ifndef _ITAPS_FC_FUNC_H_
>   #define _ITAPS_FC_FUNC_H_
> 
>   /* following line is for specific platform, compiler... combination */
>   #define FC_FUNC(lowFunc,UPfunc) UPfunc
> 
>   #endif
> 
> - Onkar
> 
> >
> > The only issue I see with this approach is that you need to have defined
> ahead of time all the possible #ifdef #elif cases above and whenever you
> go to a new machine, then you'll have to re-visit this logic. So, I like
> the approach where Autconf's configure is used to set FC_FUNC.
> >
> > Finally, whatever FC_FUNC is set to, it MUST match the actual name
> mangling used by whatever fortran compiler is being used to compile the
> code. So, it is not just a matter of everyone agreeing on an
> > implementation for FC_FUNC. FC_FUNC must also address whatever name
> mangling is being used by a given fortran compiler on a given platform
> when the code is getting compiled. For that reason, I think the best
> approach is the Autoconf approach.
> >
> > Mark
> >
> >
> > --
> > Mark C. Miller, Lawrence Livermore National Laboratory
> > email: mailto:miller86 at llnl.gov
> > (M/T/W) (925)-423-5901 (!!LLNL BUSINESS ONLY!!)
> > (Th/F)  (530)-753-8511 (!!LLNL BUSINESS ONLY!!)
> >
> >
> 
> 
> 
> 
-- 
Mark C. Miller, Lawrence Livermore National Laboratory
email: mailto:miller86 at llnl.gov
(M/T/W) (925)-423-5901 (!!LLNL BUSINESS ONLY!!)
(Th/F)  (530)-753-8511 (!!LLNL BUSINESS ONLY!!)