[PATCH] gas: support for .pushsection and .popsection pseudo ops for coff

[Johannes Khoshnazar-Thoma]

Dear list,

Friendly ping regarding my .pushsection patch. Is this something
that could be merged? What else do you need?

Thank you for your attention,

Best regards,

- Johannes

Am 18.07.26 um 18:22 schrieb Johannes Khoshnazar-Thoma:
> Current Linux kernels make heavy use of the .pushsection and
> .popsection pseudo ops. Normally, the Linux kernel is built
> as an ELF object, where the assembler supports those pseudo
> ops. When compiling the Linux kernel as a Windows/ReactOS
> driver however, it must be compiled as a COFF object, since
> the Windows/ReactOS kernel does not know how to load ELF
> binaries.
> 
> In order to be able to compile the Linux kernel as a COFF
> object (and further on as a PE32 native executable) the
> implementation of those pseudo ops has been copiied from
> the obj-elf.c support code to the obj-coff.c support code.
> It has been verified that the Linux kernel works without
> assembler errors when using an assembler with this patch.
> 
> Signed-off-by: Johannes Khoshnazar-Thoma <johannes@johannesthoma.com>
> ---
>   gas/config/obj-coff.c | 41 ++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 40 insertions(+), 1 deletion(-)
> 
> diff --git a/gas/config/obj-coff.c b/gas/config/obj-coff.c
> index 7732c0af911..73c571b71de 100644
> --- a/gas/config/obj-coff.c
> +++ b/gas/config/obj-coff.c
> @@ -1536,6 +1536,32 @@ obj_coff_finalize_section_relocs (asection *sec, arelent **relocs,
>     return true;
>   }
>   
> +struct section_stack
> +{
> +  struct section_stack *next;
> +  segT seg;
> +  int subseg;
> +};
> +
> +static struct section_stack *section_stack;
> +
> +static void
> +obj_coff_popsection (int xxx ATTRIBUTE_UNUSED)
> +{
> +  struct section_stack *top = section_stack;
> +
> +  if (top == NULL)
> +    {
> +      as_warn (_(".popsection without corresponding .pushsection; ignored"));
> +      return;
> +    }
> +
> +  section_stack = top->next;
> +  subseg_set (top->seg, top->subseg);
> +  free (top);
> +}
> +
> +
>   /* Implement the .section pseudo op:
>     	.section name {, "flags"}
>                     ^         ^
> @@ -1559,7 +1585,7 @@ obj_coff_finalize_section_relocs (asection *sec, arelent **relocs,
>      .section directive to be parsed in both ELF and COFF formats.  */
>   
>   void
> -obj_coff_section (int ignore ATTRIBUTE_UNUSED)
> +obj_coff_section (int push)
>   {
>     /* Strip out the section name.  */
>     char *section_name;
> @@ -1691,6 +1717,17 @@ obj_coff_section (int ignore ATTRIBUTE_UNUSED)
>   	}
>       }
>   
> +  /* .pushsection implementation */
> +  if (push)
> +    {
> +      struct section_stack *elt;
> +      elt = XNEW (struct section_stack);
> +      elt->next = section_stack;
> +      elt->seg = now_seg;
> +      elt->subseg = now_subseg;
> +      section_stack = elt;
> +    }
> +
>     sec = subseg_new (name, exp);
>   
>     if (is_bss)
> @@ -1903,6 +1940,8 @@ static const pseudo_typeS coff_pseudo_table[] =
>     {"sect.s", obj_coff_section, 0},
>     {"section", obj_coff_section, 0},
>     {"section.s", obj_coff_section, 0},
> +  {"pushsection", obj_coff_section, 1},
> +  {"popsection", obj_coff_popsection, 0},
>     /* FIXME: We ignore the MRI short attribute.  */
>     {"size", obj_coff_size, 0},
>     {"tag", obj_coff_tag, 0},