[PATCH] readelf -d RELASZ excludes .rela.plt size

[Fangrui Song]

On Wed, Aug 9, 2023 at 5:30 AM mengqinggang <mengqinggang@loongson.cn> wrote:
>
> Before, readelf -d RELASZ is the sum of .rela.dyn size and .rela.plt size.
> To consistent with LoongArch lld, RELASZ chang to only the size of .rela.dyn.
> ---
>  bfd/elfnn-loongarch.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
> index 70a666283af..5d5ca19d490 100644
> --- a/bfd/elfnn-loongarch.c
> +++ b/bfd/elfnn-loongarch.c
> @@ -4663,4 +4663,6 @@ elf_loongarch64_hash_symbol (struct elf_link_hash_entry *h)
>  #define elf_backend_hash_symbol elf_loongarch64_hash_symbol
>  #define bfd_elfNN_bfd_relax_section loongarch_elf_relax_section
>
> +#define elf_backend_dtrel_excludes_plt 1
> +
>  #include "elfNN-target.h"
> --
> 2.36.0
>

LGTM. glibc rtld supports overlapping [DT_RELA,DT_RELA+DT_RELASZ) and
[DT_JMPREL,DT_JMPREL+DT_PLTRELSZ).

I suspect that this is inherited (in the 1990s) from older loaders
that added DT_JMPREL as an optimization without breaking existing
loaders not supporting DT_JMPREL. This design choice is not good for
modern architectures that support DT_JMPREL since the beginning.