Re: [PATCH] x86-64: Allocate input section memory if needed

[Alan Modra <amodra@gmail.com>]

On Wed, Dec 28, 2022 at 09:23:21AM -0800, H.J. Lu wrote:
> On Tue, Dec 27, 2022 at 5:16 PM Alan Modra <amodra@gmail.com> wrote:
> >
> > On Tue, Dec 27, 2022 at 11:47:56AM -0800, H.J. Lu via Binutils wrote:
> > > +                       /* Cache the section contents for
> > > +                          elf_link_input_bfd.  */
> > > +                       elf_section_data (sec)->this_hdr.contents
> > > +                         = contents;
> >
> > You shouldn't really be caching unaltered section contents when
> > !info->keep_memory.  I'm not saying the patch is wrong, but please fix
> > this when you have some time.
> >
> > --
> > Alan Modra
> > Australia Development Lab, IBM
> 
> elf_x86_64_scan_relocs has
> 
>   if (elf_section_data (sec)->this_hdr.contents != contents)
>     {
>       if (!converted && !_bfd_link_keep_memory (info))
>         free (contents);
>       else
>         {
>           /* Cache the section contents for elf_link_input_bfd if any
>              load is converted or --no-keep-memory isn't used.  */
>           elf_section_data (sec)->this_hdr.contents = contents;
>           info->cache_size += sec->size;
>         }
>     }
> 
> Are you suggesting that it should be

No, the code above is correct and how it should be in
elf_x86_size_or_finish_relative_reloc.  Of course it is a little more
complicated there due to handling multiple sections.

> 
>   if (elf_section_data (sec)->this_hdr.contents != contents)
>     {
>       if (!converted)
>         free (contents);
>       else
>         {
>           /* Cache the section contents for elf_link_input_bfd if any
>              load is converted.  */
>           elf_section_data (sec)->this_hdr.contents = contents;
>           info->cache_size += sec->size;
>         }
>     }

This would be wrong as it ignores info->keep_memory.

-- 
Alan Modra
Australia Development Lab, IBM