[PATCH 3/3] bfd: x86: sframe: additonal check in _bfd_x86_elf_link_setup_gnu_properties

[Jens Remus]

On 1/12/2026 11:53 AM, claudiu.zissulescu-ianculescu--- via Binutils wrote:
> From: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>
> 
> GNU ld creates SFrame stack trace info for the .plt* sections.  These
> linker created sections are created in
> _bfd_x86_elf_link_setup_gnu_properties (), but data is emitted into
> them a bit later in _bfd_x86_elf_late_size_sections ().

What is the plan regarding s390x (AArch64 AFAIK does not emit .sframe
for PLT)?

> 
> With SFrame sections now marked KEEP in scripttempl/elf.sc, and the
> presence of these linker created SFrame sections cause emission of an
> empty .sframe for all ELF targets (IIUC), even when all input bfd's
> have no .sframe section.  This patch is avoiding creation of empty
> .sframe in linked objects on x86_64, when none of the inputs had
> SFrame sections.
> 
> bfd/
> 
> 	* elfxx-x86.c (_bfd_x86_elf_link_setup_gnu_properties): Emit
> 	sframe section only when required.
> 
> Co-authored-by: Indu Bhagat <indu.bhagat@oracle.com>
> Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>

> diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c

> @@ -4834,8 +4834,30 @@ _bfd_x86_elf_link_setup_gnu_properties
>  	    }
>  	}
>  
> +      bool gen_plt_sframe_p = false;
>        /* .sframe sections are emitted for AMD64 ABI only.  */
>        if (ABI_64_P (info->output_bfd) && !info->no_ld_generated_unwind_info)
> +	{
> +	  /* Find in any input file has an .sframe section.  */
> +	  for (pbfd = info->input_bfds; pbfd != NULL; pbfd = pbfd->link.next)
> +	    if (bfd_get_flavour (pbfd) == bfd_target_elf_flavour
> +		&& bfd_count_sections (pbfd) != 0)
> +	      {
> +		asection *sfsec = bfd_get_section_by_name (pbfd, ".sframe");

This tests for the existence of a section with name ".sframe".  Would it
make sense to test for any section of type SHT_GNU_SFRAME instead?

> +		if (sfsec != NULL)
> +		  {
> +		    gen_plt_sframe_p = true;
> +		    break;
> +		  }
> +	      }
> +	}
> +
> +      /* Do not make SFrame sections for dynobj unconditionally.  If there
> +	 are no SFrame sections for any input files, skip creating the linker
> +	 created SFrame sections too.  Since SFrame sections are marked KEEP,
> +	 prohibiting these linker-created SFrame sections when unnecessary,
> +	 helps avoid creating of empty SFrame sections in the output.  */
> +      if (gen_plt_sframe_p)
>  	{
>  	  flagword flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY
>  			    | SEC_HAS_CONTENTS | SEC_IN_MEMORY

Thanks and regards,
Jens
-- 
Jens Remus
Linux on Z Development (D3303)
jremus@de.ibm.com / jremus@linux.ibm.com

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