Re: Support AArch64 MTE memory tag dumps in core files

[Alan Modra <amodra@gmail.com>]

On Thu, Mar 31, 2022 at 03:04:57PM +0100, Luis Machado via Binutils wrote:
> diff --git a/bfd/section.c b/bfd/section.c
> index 9a1071454f5..e8c7caf9dd4 100644
> --- a/bfd/section.c
> +++ b/bfd/section.c
> @@ -412,6 +412,9 @@ CODE_FRAGMENT
>  .  {* Nonzero if this section uses RELA relocations, rather than REL.  *}
>  .  unsigned int use_rela_p:1;
>  .
> +.  {* Nonzero if this section contains memory tag data.  Default is 0.  *}
> +.  unsigned int has_memory_tags : 1;
> +.
>  .  {* Bits used by various backends.  The generic code doesn't touch
>  .     these fields.  *}
>  .
> @@ -455,6 +458,11 @@ CODE_FRAGMENT
>  .  {* The compressed size of the section in octets.  *}
>  .  bfd_size_type compressed_size;
>  .
> +.  {* If HAS_MEMORY_TAGS is true, MEMORY_TAGS_RANGE_SIZE is the original memory
> +.     range size, in octets, of the memory that contained the tags stored in this
> +.     section.  SIZE is the size of the packed tags from that memory range.  *}
> +.  bfd_size_type memory_tags_range_size;
> +.
>  .  {* Relaxation table. *}
>  .  struct relax_table *relax;
>  .

Really, you shouldn't be adding fields used by just one target to
struct bfd_section.  The linker might be dealing with hundreds of
thousands of sections.  If every target added fields because it was
convenient to do it that way, we'd end up with quite a non-trivial
memory cost for all targets.  Instead, you should look at adding the
new field to _aarch64_elf_section_data.

Yes, I know target specific fields have sneaked past review in the
past, eg. relax and relax_count are microblaze only.  I might even get
around to fixing those one day.

-- 
Alan Modra
Australia Development Lab, IBM