[PATCH v2] readelf: Add --got-contents option

[H.J. Lu]

On Fri, Aug 29, 2025 at 12:55 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 28.08.2025 23:15, H.J. Lu wrote:
> > Add --got-contents option to readelf, inspired by the -G option on Solaris,
> > to display contents of GOT sections:
> >
> > $ readelf --got-contents libfoo.so
> >
> > Global Offset Table '.got' contains 1 entry:
> >  Index:    Address       Reloc         Sym. Name + Addend/Value
> >      0: 000000200340 R_X86_64_GLOB_DAT foo + 0
> >
> > Global Offset Table '.got.plt' contains 4 entries:
> >  Index:    Address       Reloc         Sym. Name + Addend/Value
> >      0: 000000200348                   200220
> >      1: 000000200350                   0
> >      2: 000000200358                   0
> >      3: 000000200360 R_X86_64_JUMP_SLO bar + 0
> >
> > When --got-content options are used:
> >
> > 1. Allocate an array, all_relocations, to hold all relocations.
> > 2. Update dump_relr_relocations and dump_relocations to scan relocations
> > and cache them in all_relocations.  Don't display relocations if not
> > requested.
> > 3. Add process_got_section_contents to display contents of GOT sections
> > by matching the GOT entry offset against the cached relocations.
> > 4. Update process_mips_specific to only display the GOT related contents
> > for --got-contents.
> >
> > binutils/
> >
> >       * NEWS: Mention "readelf --got-contents".
> >       * readelf.c (do_got_section_contents): New.
> >       (elf_relocation): Likewise.
> >       (all_relocations_root): Likewise.
> >       (all_relocations): Likewise.
> >       (all_relocations_count): Likewise.
> >       (update_all_relocations): Likewise.
> >       (dump_relr_relocations): Add a bool argument to indicate if
> >       relocations should be displayed.  Populate all_relocations if
> >       do_got_section_contents is true.
> >       (dump_relocations): Likewise.
> >       (long_option_values): Add OPTION_GOT_CONTENTS.
> >       (options): Add --got-contents.
> >       (usage): Show --got-contents.
> >       (parse_args): Support --got-contents.
> >       (display_relocations): Add a bool argument, dump_reloc, to
> >       indicate if relocations should be displayed.  Call
> >       update_all_relocations.  Pass dump_reloc to dump_relr_relocations
> >       and dump_relocations.
> >       (process_relocs): Check do_got_section_contents.  Handle
> >       do_got_section_contents for dynamic relocations.
> >       (process_section_contents): Pass true to display_relocations.
> >       (process_mips_specific): Add a bool argument, dump_got, to
> >       indicate if only the GOT related contents should be displayed.
> >       Display all MIPS specific information if dump_got is false.
> >       (elf_relocation_cmp): New.
> >       (display_elf_relocation_at): Likewise.
> >       (process_got_section_contents): Likewise.
> >       (process_object): Call process_got_section_contents.
> >       * doc/binutils.texi: Document --got-contents.
> >
> > ld/
> >
> >       * testsuite/ld-i386/binutils.exp: New file.
> >       * testsuite/ld-i386/got-1.s: Likewise.
> >       * testsuite/ld-i386/libgot-1a.rd: Likewise.
> >       * testsuite/ld-i386/libgot-1b.rd: Likewise.
> >       * testsuite/ld-i386/libgot-1c.rd: Likewise.
> >       * testsuite/ld-i386/libgot-1d.rd: Likewise.
> >       * testsuite/ld-x86-64/binutils.exp: Likewise.
> >       * testsuite/ld-x86-64/got-1.s: Likewise.
> >       * testsuite/ld-x86-64/libgot-1a-x32.rd: Likewise.
> >       * testsuite/ld-x86-64/libgot-1a.rd: Likewise.
> >       * testsuite/ld-x86-64/libgot-1b-x32.rd: Likewise.
> >       * testsuite/ld-x86-64/libgot-1b.rd: Likewise.
> >       * testsuite/ld-x86-64/libgot-1c-x32.rd: Likewise.
> >       * testsuite/ld-x86-64/libgot-1c.rd: Likewise.
> >       * testsuite/ld-x86-64/libgot-1d-x32.rd: Likewise.
> >       * testsuite/ld-x86-64/libgot-1d.rd: Likewise.
> >
> > Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
>
> I'm still not quite happy with there being only x86 testcases (seeing in
> particular that there's some arch-specific handling in the new code), but
> of course that's better than nothing. Hence somewhat hesitantly: Okay.
>
> Jan

I am checking it in.  People can add other arch-specific tests later.

Thanks.

-- 
H.J.