i370 port - constructing compile script

[Paul Edwards]

Hi Ulrich.

I'll try out some of those things.  I have some initial
comments.

> Hmmm, the access() use probably needs to be guarded by a configure
> check.  Or else you might provide a MVS-specific implementation of
> "access" (if that is possible), and compile it into libiberty by
> providing an EXTRA_OFILES setting in a host makefile fragment;

Probably too many of them.  Just like open() etc in GCC main.
I'll see what can be faked up, now that I know those object files
are basically mandatory.

> in 3.4 these are set in config.table:
> case "${host}" in
>  rs6000-ibm-aix3.1 | rs6000-ibm-aix)
>                        frag=mh-aix ;;
>  *-*-cxux7*)           frag=mh-cxux7 ;;
>  *-*-freebsd2.1.*)     frag=mh-fbsd21 ;;
>  *-*-freebsd2.2.[012]) frag=mh-fbsd21 ;;
>  i370-*-opened*)       frag=mh-openedition ;;
>  i[34567]86-*-windows*)        frag=mh-windows ;;
> esac
> 
> As to the pex-unix.c, you certainly should provide a MVS-specific
> version of the PEX callbacks.  They are selected in configure.ac:
> 
> # Figure out which version of pexecute to use.
> case "${host}" in
>     *-*-mingw* | *-*-winnt*)   pexecute=pex-win32.o  ;;
>     *-*-msdosdjgpp*)           pexecute=pex-djgpp.o  ;;
>     *-*-msdos*)                pexecute=pex-msdos.o  ;;
>     *-*-os2-emx*)              pexecute=pex-os2.o    ;;
>     *)                         pexecute=pex-unix.o   ;;
> esac

Ok, thanks.

> Your MVS version might be just a dummy that always fails.

Ok.

> Even better would be a version that actually works; in this
> case all the "single-exectuable" hacks would become superfluous.

Having a single executable, especially in my environment where
only assembler code is ever generated, has its own merits even if
a working system() can be done in the future.

> Note that e.g. pex-msdos.c implements the required callbacks
> solely in terms of the C99 "system" routine.  If you at least
> have this facility available on MVS, you might be able to just
> use the msdos version?

I don't have a working system that can execute another C program
yet.  Note that C90 leaves the behaviour of system() as
"implementation defined".  Well, on my system, I can do a system()
to call some simple programs that clear the screen.  In one
environment on my system, anyway.  :-)

>> Finally, even with this in place, the build process stopped at
>> the next roadblock.  The file "genmodes.c" couldn't be
>> compiled.  I was surprised to see that it was being compiled
>> with i370-mvspdp-gcc.  The genmodes "needs" to be run on
>> Unix still.  It's only the source code that IT generates that
>> needs to be cross-compiled.
> 
> If this happens, then something went very wrong during configure.
> Did you make sure to use the proper build / host / target flags?
> In particular, the --build= configure argument must be present
> and refer to the build architecture.  This is used to determine
> which architecture to build the generator programs for.

Yes, I have all 3 specified, with --build of i686-linux.  Now that I
know that the generator files are meant to be built with the i686
gcc, I'll try to find out where it's picking that up from.

BFN.  Paul.