[PATCH v11 22/25] gnu directives: add support for .gnu_attribute and .gnu_subsection in OAv2 context

[Jan Beulich]

On 31.12.2025 00:05, Matthieu Longo wrote:
> --- a/gas/doc/as.texi
> +++ b/gas/doc/as.texi
> @@ -4597,6 +4597,7 @@ Some machine configurations provide additional directives.
>  * Func::                        @code{.func}
>  * Global::                      @code{.global @var{symbol}}, @code{.globl @var{symbol}}
>  @ifset ELF
> +* Gnu_subsection::              @code{.gnu_subsection @var{name}, @var{comprehension}, @var{encoding}}
>  * Gnu_attribute::               @code{.gnu_attribute @var{tag},@var{value}}
>  * Hidden::                      @code{.hidden @var{names}}
>  @end ifset

This looks like it is meant to be sorted alphabetically, so your addition
wants moving down by a line.

> @@ -5744,9 +5745,48 @@ partial programs.  You may need the HPPA-only @code{.EXPORT} directive as well.
>  @end ifset
>  
>  @ifset ELF
> +@node Gnu_subsection
> +@section @code{.gnu_subsection @var{name}, @var{comprehension}, @var{encoding}}
> +Create or switch the current object attributes subsection to @var{name} for This
> +file.  Valid values for @var{name} are following the pattern @code{[a-zA-Z0-9_]+}.
> +
> +The subsection property @var{comprehension} determines how a program processing
> +the attributes handles attributes that it does not recognize (perhaps because
> +the object file was generated by a different version of the toolchain).  A
> +subsection that is marked @code{optional} can be skipped if it is not
> +understood.  A subsection marked @code{required} implies that information
> +conveyed by the attribute is required for correct processing of the object file;
> +a fatal diagnostic must be generated if a tool does not recognize either the tag
> +or the value associated with it.
> +
> +@var{encoding} specifies the expected encoding of the attributes recorded in the
> +subsection.  Currently supported values are @code{ULEB128}/@code{uleb128} and
> +@code{NTBS}/@code{ntbs} (null-terminated byte string).
> +
> +On the first declaration of a subsection, both @var{comprehension} and
> +@var{encoding} are mandatory parameters. However, on subsequent declarations,
> +none of the parameters is required. If they are still specified, their values
> +will be matched against the ones from the first declaration. Any mismatch will
> +be reported as an error.
> +
> +This directive is only available for Object Attributes v2.
> +
> +@xref{Object Attributes}.
> +
>  @node Gnu_attribute
>  @section @code{.gnu_attribute @var{tag},@var{value}}
> -Record a @sc{gnu} object attribute for this file.  @xref{Object Attributes}.
> +
> +For Object Attributes v1, record a @sc{gnu} object attribute with the pair
> +@var{tag}, @var{value} for this file.
> +
> +For Object Attributes v2, record an object attribute with the pair @var{tag},
> +@var{value} in the current subsection for this file.
> +
> +@var{tag} can either be an integer value, or a known named key. @var{value} can
> +either be an integer or a string. For Object Attribute v2, the expected value
> +type depends on the type set on the subsection.
> +
> +@xref{Object Attributes}.
>  
>  @node Hidden
>  @section @code{.hidden @var{names}}

Same here, Gnu_subsection wants to live between Gnu_attribute and Hidden.

Okay with that adjustment.

Jan