compiling binutils with -DDEBUG
Alan Modra
amodra@bigpond.net.au
Tue Mar 1 22:02:00 GMT 2005
On Tue, Mar 01, 2005 at 09:24:54AM -0500, Ian Lance Taylor wrote:
> Alan Modra <amodra@bigpond.net.au> writes:
>
> > On Mon, Feb 28, 2005 at 09:36:00PM -0500, Ian Lance Taylor wrote:
> > > Alan Modra <amodra@bigpond.net.au> writes:
> > >
> > > > (fixup_segment): Remove assertion.
> > > > Didn't seem worth including struct-symbol.h just for this. I suspect
> > > > the assertion isn't true too, since a similar assertion in obj-coff.c
> > > > fails with X_op an O_constant. Maybe this is a real bug. Ian, you're
> > > > probably the only one who can answer mri mode queries off the top of
> > > > your head. Care to comment?
> > >
> > > > @@ -2583,7 +2585,6 @@ fixup_segment (fixS *fixP, segT this_seg
> > > > if (fixP->fx_addsy != NULL
> > > > && symbol_mri_common_p (fixP->fx_addsy))
> > > > {
> > > > - know (fixP->fx_addsy->sy_value.X_op == O_symbol);
> > > > add_number += S_GET_VALUE (fixP->fx_addsy);
> > > > fixP->fx_offset = add_number;
> > > > fixP->fx_addsy
> > >
> > > The assertion should be true. This is a symbol defined in an MRI
> > > common section. Since we don't generate IEEE object files, we treat
> > > an MRI common section as a single large common symbol. Then we handle
> > > a reloc against a symbol defined within an MRI common section as an
> > > offset to that symbol. The assertion is just checking that we really
> > > do point to the magic symbol we are using for the MRI common section.
> >
> > I did a little analysis. Nowadays, the assertion is always false for
> > BFD_ASSEMBLER because symbols have been resolved (write.c:1857) by the
> > time this code is reached. The following would probably fix the
> > assertion, but I don't think it's worth worrying about.
>
> There is code in resolve_symbol_value() to handle this case. I wonder
> why it isn't working?
The reason the assert fails is that finalize_syms is set by the time we
reach write.c:1857, so S_SET_VALUE is called for these symbols. That
turns them into O_constant values.
> If the assert in fixup_segment() fails, then
> MRI common symbols will not be handled correctly.
Are you sure? I couldn't see why it mattered that the sym was resolved
at write.c:1857 versus being resolved at write.c:2588. The mri common
testcase looks to produce good results.
--
Alan Modra
IBM OzLabs - Linux Technology Centre
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