Re: [patch/rfc] Don't complain about unknown OSABI

[Daniel Jacobowitz <drow@mvista.com>]

On Mon, Aug 19, 2002 at 07:03:07PM -0400, Andrew Cagney wrote:
> 
> >>I know.  Being able to print the OSABI would help (set/show abi).
> >
> >
> >Yes.  Did you look at the patch posted two or three days ago to add
> >set/show commands?
> 
> Yes, and it is a hard command to implement right (or even figure out 
> what implement right even means!).
> 
> >Actually, as he probably doesn't have copyright papers on file, I may
> >whip something equivalent together today.
> 
> Be sure to wear a seatbelt, the problem is harder than it looks.
> 
> >>I think it should ask BFD.  BFD can then go and look at the target 
> >>tuple. That would mean that BFD and GDB are ``on the same page''.   See 
> >>the hacks I've got GDB pulling to figure out the default architecture.
> >
> >
> >This doesn't make sense to me.  The different is that BFD and GDB both
> >have a notion of architecture; but BFD has no notion of OSABI.  The
> >distinguishing markers we use come from the system libraries as often
> >as not.
> 
> Something in binutils knows what the basic OS is.   The linker often 
> knows to brand the executable a certain way (although increasingly it is 
> the compiler that is telling the linker everything).  What executable, 
> for instance, does:
> 
> 	as -o s.o /dev/null
> 	ld s.o
> 
> create?
> 
> >My suggestion:  First we'd add set/show osabi, with settings for each
> >(known?  Registered?  I think registered.) OSABI.  Then it would also
> >have "default" and "auto".  The difference is that auto would use the
> >detection mechanism and fall back to default if necessary, and default
> >would be fixed.  Then we'd set the default in one of two ways:
> >
> > - Specify the default value in configure.tgt
> > - Do some analysis of the target triplet in osabi.c
> >
> >I'm inclined to go with a list of registered OSABI's,
> 
> It should match against the registered OSABI's.
> 
> > and to set the
> >default at configure time.  How's that sound?
> 
> GDB uses ../bfd/config.bfd to find the default architecture.  I think 
> this has made our lives much easier -- gdb's and bfd's defaults match 
> and we don't have to maintain anything.  It really is a ``free lunch'' :-)
> 
> Is there an equivalent for the OS/ABI?  If we can pick that default up 
> from binutils then we also get that for free.  On the other hand if we 
> start wiring this stuff into configure.tgt (duplicating ld/gcc) we take 
> on an additional maintenance task.

Exactly my point.  There is no OS/ABI equivalent; BFD doesn't know what
it is, and doesn't need to.

I'll try to put this together tomorrow.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer