[PATCH v3 2/3] ld: bfd: sframe: KEEP .sframe sections and support gc-sections
Indu Bhagat
indu.bhagat@oracle.com
Fri Jan 23 06:27:25 GMT 2026
On 1/22/26 12:00 AM, claudiu.zissulescu-ianculescu@oracle.com wrote:
> From: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>
>
> Fix PR ld/32769
>
> Currently, specifying --gc-sections causes the linker to discard all
> input .sframe sections. Fix this behaviour by adding KEEP for .sframe
> sections in the default ELF linker script.
>
> Additionally, add logic in the linker to gc mark .sframe sections.
> _bfd_elf_gc_mark () now is aware of SFrame sections. It relies on
> elf_section_sframe () to get the SFrame section associated with the text
> section.
>
> The stub changes in bfd_elf_discard_info skip checking the return
> value of _bfd_elf_parse_sframe because it may have already been
> parsed.
>
> ld/
> PR ld/32769
> * scripttempl/elf.sc: KEEP .sframe sections.
> bfd/
> * elf-bfd.h (struct elf_obj_tdata): Add sframe section pointer.
> (elf_sframe_section): New macro.
> * elflink.c (_bfd_elf_gc_mark): Handle SFrame sections.
> (bfd_elf_gc_sections): Likewise.
> (bfd_elf_discard_info): Update for handling gc operations.
>
> Co-authored-by: Indu Bhagat <indu.bhagat@oracle.com>
> Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>
> ---
> bfd/elf-bfd.h | 5 +++++
> bfd/elflink.c | 38 ++++++++++++++++++++++++++++----------
> ld/scripttempl/elf.sc | 4 ++--
> 3 files changed, 35 insertions(+), 12 deletions(-)
>
> diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
> index c833b7d101b..94525b3606e 100644
> --- a/bfd/elf-bfd.h
> +++ b/bfd/elf-bfd.h
> @@ -2177,6 +2177,9 @@ struct elf_obj_tdata
> /* A pointer to the .eh_frame section. */
> asection *eh_frame_section;
>
> + /* A pointer to the .sframe section. */
> + asection *sframe_section;
> +
> /* Symbol buffer. */
> void *symbuf;
>
> @@ -2258,6 +2261,8 @@ struct elf_obj_tdata
> #define elf_dynverref(bfd) (elf_tdata(bfd) -> dynverref_section)
> #define elf_eh_frame_section(bfd) \
> (elf_tdata(bfd) -> eh_frame_section)
> +#define elf_sframe_section(bfd) \
> + (elf_tdata(bfd) -> sframe_section)
> #define elf_section_syms(bfd) (elf_tdata(bfd) -> o->section_syms)
> #define elf_num_section_syms(bfd) (elf_tdata(bfd) -> o->num_section_syms)
> #define core_prpsinfo(bfd) (elf_tdata(bfd) -> prpsinfo)
> diff --git a/bfd/elflink.c b/bfd/elflink.c
> index 64c1a57b465..db74591489d 100644
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -14151,7 +14151,7 @@ _bfd_elf_gc_mark (struct bfd_link_info *info,
> elf_gc_mark_hook_fn gc_mark_hook)
> {
> bool ret;
> - asection *group_sec, *eh_frame;
> + asection *group_sec, *eh_frame, *sframe;
>
> sec->gc_mark = 1;
>
> @@ -14164,9 +14164,12 @@ _bfd_elf_gc_mark (struct bfd_link_info *info,
> /* Look through the section relocs. */
> ret = true;
> eh_frame = elf_eh_frame_section (sec->owner);
> + sframe = elf_sframe_section (sec->owner);
> +
> if ((sec->flags & SEC_RELOC) != 0
> && sec->reloc_count > 0
> - && sec != eh_frame)
> + && sec != eh_frame
> + && sec != sframe)
> {
> struct elf_reloc_cookie cookie;
>
> @@ -14703,6 +14706,23 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
> fini_reloc_cookie_for_section (&cookie, sec);
> sec = bfd_get_next_section_by_name (NULL, sec);
> }
> +
> + /* Now parse each .sframe section. Point each .sframe secto to
> + each bfd. */
typo: secto
> + sec = bfd_get_section_by_name (sub, ".sframe");
> + while (sec
> + && init_reloc_cookie_for_section (&cookie, info, sec, false))
Nit: what about following the same style as the code few lines above in
this function
while (sec && init_reloc_cookie_for_section (&cookie, info, sec,
false))
> + {
> + _bfd_elf_parse_sframe (sub, info, sec, &cookie);
> +
> + if (sec->sec_info
> + && (sec->flags & SEC_LINKER_CREATED) == 0)
> + elf_sframe_section (sub) = sec;
> +
> + fini_reloc_cookie_for_section (&cookie, sec);
> + sec = bfd_get_next_section_by_name (NULL, sec);
> + }
> +
Unnecessary new line?
> }
>
> /* Apply transitive closure to the vtable entry usage info. */
> @@ -15302,15 +15322,13 @@ bfd_elf_discard_info (bfd *output_bfd, struct bfd_link_info *info)
> if (!init_reloc_cookie_for_section (&cookie, info, i, false))
> return -1;
>
> - if (_bfd_elf_parse_sframe (abfd, info, i, &cookie))
> + _bfd_elf_parse_sframe (abfd, info, i, &cookie);
> + if (_bfd_elf_discard_section_sframe (i,
> + bfd_elf_reloc_symbol_deleted_p,
> + &cookie))
> {
> - if (_bfd_elf_discard_section_sframe (i,
> - bfd_elf_reloc_symbol_deleted_p,
> - &cookie))
> - {
> - if (i->size != i->rawsize)
> - changed = 1;
> - }
> + if (i->size != i->rawsize)
> + changed = 1;
> }
> fini_reloc_cookie_for_section (&cookie, i);
> }
> diff --git a/ld/scripttempl/elf.sc b/ld/scripttempl/elf.sc
> index 80b4b512536..8a0efc02c86 100644
> --- a/ld/scripttempl/elf.sc
> +++ b/ld/scripttempl/elf.sc
> @@ -719,7 +719,7 @@ cat <<EOF
> ${OTHER_READONLY_SECTIONS}
> .eh_frame_hdr ${RELOCATING-0} : { *(.eh_frame_hdr)${RELOCATING+ *(.eh_frame_entry .eh_frame_entry.*)} }
> .eh_frame ${RELOCATING-0} : ONLY_IF_RO { KEEP (*(.eh_frame))${RELOCATING+ *(.eh_frame.*)} }
> - .sframe ${RELOCATING-0} : ONLY_IF_RO { *(.sframe)${RELOCATING+ *(.sframe.*)} }
> + .sframe ${RELOCATING-0} : ONLY_IF_RO { KEEP (*(.sframe))${RELOCATING+ *(.sframe.*)} }
> .gcc_except_table ${RELOCATING-0} : ONLY_IF_RO { *(.gcc_except_table${RELOCATING+ .gcc_except_table.*}) }
> .gnu_extab ${RELOCATING-0} : ONLY_IF_RO { *(.gnu_extab*) }
>
> @@ -794,7 +794,7 @@ emit_data()
> cat <<EOF
> /* Exception handling. */
> .eh_frame ${RELOCATING-0} : ONLY_IF_RW { KEEP (*(.eh_frame))${RELOCATING+ *(.eh_frame.*)} }
> - .sframe ${RELOCATING-0} : ONLY_IF_RW { *(.sframe)${RELOCATING+ *(.sframe.*)} }
> + .sframe ${RELOCATING-0} : ONLY_IF_RW { KEEP (*(.sframe))${RELOCATING+ *(.sframe.*)} }
> .gnu_extab ${RELOCATING-0} : ONLY_IF_RW { *(.gnu_extab) }
> .gcc_except_table ${RELOCATING-0} : ONLY_IF_RW { *(.gcc_except_table${RELOCATING+ .gcc_except_table.*}) }
> .exception_ranges ${RELOCATING-0} : ONLY_IF_RW { *(.exception_ranges${RELOCATING+*}) }
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