Re: RFC: using ld 2.14 on irix

["Maciej W. Rozycki" <macro at ds2 dot pg dot gda dot pl>]

On 14 Jun 2003, Richard Sandiford wrote:

> > With these changes I was able to successfully bootstrap gcc 3.4
> > using GNU as & ld.  There seem to be some problems with the DSOs
> > it created, looking at that now.  (The DSOs created by the unpatched
> > linker fail too, so it might not be caused by these patches.)
> 
> Hmm, beginning to wish I'd stuck to gcc. ;)
> 
> To quote the R_MIPS_REL32 passage again:
> 
> >     The value EA used by the dynamic linker to relocate an R_MIPS_REL32
> >     relocation depends on its r_symndx value.  If the relocation entry
> >     r_symndx is less than DT_MIPS_GOTSYM, the value of EA is the symbol
> >     st_value plus displacement.  Otherwise, the value of EA is the
> >     value in the GOT entry corresponding to the relocation entry
> >     r_symndx.
> 
> and the R_MIPS_REL32 equation is:
> 
> >     A - EA + S
> 
> where A is the in-place addend and S is the final symbol value.
> So if a relocation is against a global symbol, the process seems to be:
> 
>    - subtract the initial contents of the symbol's GOT entry
>    - add in the symbol's final value
> 
> (Note: I think the passage must mean the initial value of the
> GOT entry since the final value will usually be S.)

 ;-) The subject of possible interpretations of the definition of the
calculation was already beaten to death here and elsewhere. 

> Unfortunately, the patch breaks mipsel-linux-gnu.  glibc seems to have
> a very different idea about how to apply R_MIPS_REL32.  Looking at
> dl-machine.h (2.2.5 and 2.3.2), it adjusts the GOT before applying any
> relocations, then it adds the (final) GOT entries to the relocation fields.
> 
> Am I going insane, or is there really a fundamental difference here?
> If the latter, is it a known problem?  I don't see how we can keep
> both glibc and irix rld happy.

 There was a discussion on the incompatibilities recently -- see
'http://sources.redhat.com/ml/binutils/2003-02/msg00345.html'.  Ralf might
shed additional light on the dependencies.  The patch he proposed isn't
that bad in principle.

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +