[rfc] For mips, sign-extended ecoff offsets

Andrew Cagney ac131313@cygnus.com
Mon Jun 19 19:23:00 GMT 2000


Alan Modra wrote:
> 
> On Tue, 20 Jun 2000, Andrew Cagney wrote:
> 
> > > I'm worried about what happens if things like PDR.adr get changed from
> > > 0xa0000000 to 0xffffffffa0000000.
> >
> > Thats why I'm asking :-) Remember though, on the MIPS platform, if
> > ``PDR.adr'' is an address then, the canonical form of the value
> > ``0xa0000000'' obtained from an elf32 binary is 0xffffffffa00000000.
> > GDB and BFD have, for too many years, been bribed and cajoled into
> > perpetuated the lie that MIPS doesn't sign extend addresses.   GDB's now
> > decided to come clean on this matter (and purge an amazing amount of
> > bogus code :-).
> 
> Well, it's the likelihood of other "bogus code" existing in binutils that
> assumes addresses are _not_ sign extended that worries me.  If you work to
> the "You break it, you fix it" rule, then you may be taking on quite a bit
> of work :-)

I can help to an extent, however, to be honest, I'm having enough fun
just re-stablizing the the GDB side of the MIPS.  Consequently I'd be
focusing on GDB specific problems.  People on the BFD/MIPS side will
need to be willing to help if there is fallout.

> > Any way I've attached a revised patch.  I wasn't ruthless enough the
> > first time....  With this revision the linker appears to work :-)
> > Testing is continuing.
> 
> There's an ECOF_ typo still in a comment.

Thanks.

> > I guess the question for BFD people is, is this the correct approach to
> > fixing this bug?
> 
> I'd like to hear Ian's comments on this before you check it in.

Ian has a long memory (Nick does to :-) and both would be very familar
with the underlying problems and the very long history that is behind
this :-)

	Andrew


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