Re: MIPS ELF ld -Ur fails

["H . J . Lu" <hjl at lucon dot org>]

On Tue, Oct 23, 2001 at 04:50:21PM -0700, Earl Chew wrote:
> "H . J . Lu" wrote:
> > I looked at the code. The problem is in elf_bfd_final_link,
> > elf_link_size_reloc_section is called before
> > bfd_section_reloc_link_order can update
> > elf_section_data(o)->rel_count.
> 
> Did you consider my patch?
> 
> Does it solve the underlying problem, or just paper over the bug?
> 
> > How should we fix it?
> 
> Regarding the nature of the problem, as I understand it, with
> things the way they stand, elf_section_reloc_link_order() cannot
> be called before elf_link_size_reloc_section() since the former
> assumes relocation array space has been allocated by the latter.
> 
> In its current incarnation, elf_section_reloc_link_order()
> not only updates elf_section_data(o)->rel_count, it also
> modifies the relocation information.
> 
> This means that elf_link_size_reloc_section() must be called
> before elf_section_reloc_link_order().
> 
> However, the relocation space required by elf_section_reloc_link_order()
> is not accounted for when elf_link_size_reloc_section()
> allocates relocation space.
> 
> If you look at the equivalent code in binutils-2.7 (which
> doesn't have the bug), I think you'll find that the count was
> held exclusively in o->reloc_count. Remnants of that code remain
> as the first loop in elf_bfd_final_link() which updates o->reloc_count.
> 
> In binutils-2.7, o->reloc_count was used to size the relocation
> area. Now, the relocation area is sized by
> elf_section_data(o)->rel_count and elf_section_area(o)->rel_count2,
> and I think you'll find that at the place I inserted the
> BFD_ASSERT() in my patch:
> 
>         o->reloc_count != elf_section_data(o)->rel_count +
>                           elf_section_data(o)->rel_count2;
> 
> In other words, the counts are inconsistent.
> 
> So, I believe that the bug is that the relocation size counts
> fed to elf_link_size_reloc_section() is incorrect, and the
> appropriate fix is to correct the way the counts are
> maintained and updated.
> 

I believe it is a generic -Ur bug, not mips specific. Earl's patch make
senses to me. Unless there is a better way to fix it, I think we should
apply it.


H.J.