[Bug c++/110734] Attributes cannot be applied to asm declaration

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110734

--- Comment #21 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:e5153e7d63b4cd9a3df490809c4f3fe1e94d3d37

commit r14-6187-ge5153e7d63b4cd9a3df490809c4f3fe1e94d3d37
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Dec 5 17:38:46 2023 +0100

    c++: Implement C++ DR 2262 - Attributes for asm-definition [PR110734]

    Seems in 2017 attribute-specifier-seq[opt] was added to asm-declaration
    and the change was voted in as a DR.

    The following patch implements it by parsing the attributes and warning
    about them.

    I found one attribute parsing bug I'll send a fix for momentarily.

    And there is another thing I wonder about: with -Wno-attributes= we are
    supposed to ignore the attributes altogether, but we are actually still
    warning about them when we emit these generic warnings about ignoring
    all attributes which appertain to this and that (perhaps with some
    exceptions we first remove from the attribute chain), like:
    void foo () { [[foo::bar]]; }
    with -Wattributes -Wno-attributes=foo::bar
    Shouldn't we call some helper function in cases like this and warn
    not when std_attrs (or how the attribute chain var is called) is non-NULL,
    but if it is non-NULL and contains at least one non-attribute_ignored_p
    attribute?  cp_parser_declaration at least tries:
          if (std_attrs != NULL_TREE && !attribute_ignored_p (std_attrs))
            warning_at (make_location (attrs_loc, attrs_loc, parser->lexer),
                        OPT_Wattributes, "attribute ignored");
    but attribute_ignored_p here checks the first attribute rather than the
    whole chain.  So it will incorrectly not warn if there is an ignored
    attribute followed by non-ignored.

    2023-12-05  Jakub Jelinek  <jakub@redhat.com>

            PR c++/110734
            * parser.cc (cp_parser_block_declaration): Implement C++ DR 2262
            - Attributes for asm-definition.  Call cp_parser_asm_definition
            even if RID_ASM token is only seen after sequence of standard
            attributes.
            (cp_parser_asm_definition): Parse standard attributes before
            RID_ASM token and warn for them with -Wattributes.

            * g++.dg/DRs/dr2262.C: New test.
            * g++.dg/cpp0x/gen-attrs-76.C (foo, bar): Don't expect errors
            on attributes on asm definitions.
            * g++.dg/gomp/attrs-11.C: Remove 2 expected errors.