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

["H.J. Lu" <hjl.tools@gmail.com>]

On Tue, Dec 27, 2022 at 11:47 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> When --no-keep-memory is used, the input section memory may not be cached.
> Allocate input section memory for -z pack-relative-relocs if needed.
>
> bfd/
>
>         PR ld/29939
>         * elfxx-x86.c (elf_x86_size_or_finish_relative_reloc): Allocate
>         input section memory if needed.
>
> ld/
>
>         PR ld/29939
>         * testsuite/ld-elf/dt-relr-2i.d: New test.
> ---
>  bfd/elfxx-x86.c                  | 25 +++++++++++++++++++++++--
>  ld/testsuite/ld-elf/dt-relr-2i.d | 17 +++++++++++++++++
>  2 files changed, 40 insertions(+), 2 deletions(-)
>  create mode 100644 ld/testsuite/ld-elf/dt-relr-2i.d
>
> diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
> index 2ddca340473..ec86e75eba9 100644
> --- a/bfd/elfxx-x86.c
> +++ b/bfd/elfxx-x86.c
> @@ -1541,12 +1541,33 @@ elf_x86_size_or_finish_relative_reloc
>                     }
>                   else
>                     {
> +                     bfd_byte *contents;
> +
>                       if (rel.r_offset >= sec->size)
>                         abort ();
> +
> +                     if (elf_section_data (sec)->this_hdr.contents
> +                         != NULL)
> +                       contents
> +                         = elf_section_data (sec)->this_hdr.contents;
> +                     else
> +                       {
> +                         if (!bfd_malloc_and_get_section (sec->owner,
> +                                                          sec,
> +                                                          &contents))
> +                           info->callbacks->einfo
> +                             /* xgettext:c-format */
> +                             (_("%F%P: %pB: failed to allocate memory for section `%pA'\n"),
> +                              info->output_bfd, sec);
> +
> +                         /* Cache the section contents for
> +                            elf_link_input_bfd.  */
> +                         elf_section_data (sec)->this_hdr.contents
> +                           = contents;
> +                       }
>                       htab->elf_write_addend
>                         (info->output_bfd, outrel->r_addend,
> -                        (elf_section_data (sec)->this_hdr.contents
> -                         + rel.r_offset));
> +                        contents + rel.r_offset);
>                     }
>                 }
>             }
> diff --git a/ld/testsuite/ld-elf/dt-relr-2i.d b/ld/testsuite/ld-elf/dt-relr-2i.d
> new file mode 100644
> index 00000000000..ed0ef9ccded
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/dt-relr-2i.d
> @@ -0,0 +1,17 @@
> +#source: dt-relr-2.s
> +#ld: -e _start -pie --no-keep-memory $DT_RELR_LDFLAGS
> +#readelf: -rW -d
> +#target: [supports_dt_relr]
> +
> +#...
> + 0x[0-9a-f]+ \(RELR\)    +0x[0-9a-f]+
> + 0x[0-9a-f]+ \(RELRSZ\)  +(8|16) \(bytes\)
> + 0x[0-9a-f]+ \(RELRENT\) +(4|8) \(bytes\)
> +#...
> +Relocation section '\.rel(a|)\.dyn' at offset 0x[0-9a-f]+ contains 1 entry:
> +#...
> +[0-9a-f]+ +[0-9a-f]+ +R_.*_(RELATIVE|UADDR.*) .*
> +#...
> +Relocation section '\.relr\.dyn' at offset 0x[0-9a-f]+ contains 2 entries:
> +  4 offsets
> +#pass
> --
> 2.38.1
>

I am backporting it to 2.39 branch.

-- 
H.J.