Re: rs6000/sysv4.h SLOW_UNALIGNED_ACCESS and STRICT_ALIGNMENT

[Geoff Keating <geoffk at cygnus dot com>]

> From: Franz Sirl <Franz.Sirl-kernel@lauterbach.com>
> Date: Tue, 4 Jan 2000 22:53:55 +0100
> Cc: gcc-patches@gcc.gnu.org, meissner@cygnus.com
> 
> Am Tue, 04 Jan 2000 schrieb David Edelsohn:
> >>>>>> Geoff Keating writes:
> >
> >>> This patch undefines the new AIX-dependent macros added to
> >>> rs6000.h.
> >
> >Geoff> If they were AIX-dependent, why weren't they in an AIX-dependent
> >Geoff> header file?  There's already way too much random junk in rs6000.h now.
> >
> >	Because there is no single, central AIX-specific header file.  The
> >"rs6000" port originally only was AIX.  As the port evolved to support
> >additional platforms, the AIX-specific definitions were not separated from
> >the POWER/PowerPC common definitions.  The AIX-specific headers that do
> >exist are deltas for features specific to various AIX releases.
> >
> >	Starting over, one would structure the port differently, but
> >development instead chose to evolve the port with the least disruptive
> >change. 
> 
> Well, AFAI understand it, this will change in the near future due to the new
> configure-based include scheme. So this maybe a good time to start with a
> cleanup now. So it would be nice if the AIX-people would start to split out
> their stuff into a separate headerfile. After such a change it would probably
> be easy to change the other OSes.
> 
> For Linux/PPC this would mean that tm.h will have the following entries similar
> to this list:
> 
> #include <rs6000/rs6000.h>
> #include <svr4.h>
> #include <rs6000/sysv4.h>
> #include <linux.h>
> #include <rs6000/linux.h>
> 
> Currently this is very hard to do because of all the #define/#include/#undef
> trickery done in various headers.

OK.  Let's start doing this on the branch now.  I will create an
<aix.h> header, and we can see what should go into it.  Initially, the
<aix[34]*.h> headers will still have to #include these manually, but
this is no problem to change later.


-- 
- Geoffrey Keating <geoffk@cygnus.com>