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

[Daniel Jacobowitz <drow@mvista.com>]

On Tue, Aug 20, 2002 at 12:03:32PM -0400, Andrew Cagney wrote:
> 
> >>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.

No, I won't.  Too much arguing about the interaction with set
architecture that I didn't find in my inbox till after I said that.
I'd be willing to put together a version that didn't do that, leaving
the subtleties for a later hacker, but I expect Andrew wouldn't like
that very much :)

> Ah, M'kay :-)
> 
> Next question.  Given an unbranded mips-elf binary, what should the 
> following GDB's do?
> 
> gdb
> m68k-linux-gnu-gdb

Probably complain, unknown architecture.  Yes, I know you mentioned
that one can do a certain amount of debugging with just an ELF-aware
GDB.  Not enough that the OSABI ever comes into play, though.

> mips-gdb
> linux-gnu-gdb
> elf-gdb

These are all exceedingly hypothetical beasts at the moment, so I don't
know quite what you mean by the "triplet"s.

> mips-linux-gnu-gdb
> mips-netbsd-gdb

Default to Linux, default to NetBSD.

> Having the behavour key off the target creates a problem with an 
> identical executable behaving differently with different, but similar 
> GDBs.  I suspect it will encourage people to build different GDB's for 
> identical purposes when just a single GDB is needed.

That's my point though.  I _need_ for a MIPS/Linux GDB to default to
MIPS/Linux if there's a missing branding.  That's an ease-of-use,
obviousness-of-use thing.  GDB has to accept that its detection
mechanisms are sometimes imperfect.  There will be a set osabi command
of some sort, it now seems, so the user could always override if
necessary.

Just a single GDB is needed.  But using the right tool for the task, or
at least a wrapper which sets the right variables for the task...

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer