https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101940
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:a1ad0d84d7fcbcaa7a697290387b911eb7e1bd46 commit r12-5123-ga1ad0d84d7fcbcaa7a697290387b911eb7e1bd46 Author: Marek Polacek <pola...@redhat.com> Date: Thu Sep 9 09:17:27 2021 -0400 attribs: Implement -Wno-attributes=vendor::attr [PR101940] It is desirable for -Wattributes to warn about e.g. [[deprecate]] void g(); // typo, should warn However, -Wattributes also warns about vendor-specific attributes (that's because lookup_scoped_attribute_spec -> find_attribute_namespace finds nothing), which, with -Werror, causes grief. We don't want the -Wattributes warning for [[company::attr]] void f(); GCC warns because it doesn't know the "company" namespace; it only knows the "gnu" and "omp" namespaces. We could entirely disable warning about attributes in unknown scopes but then the compiler would also miss typos like [[company::attrx]] void f(); or [[gmu::warn_used_result]] int write(); so that is not a viable solution. A workaround is to use a #pragma: #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wattributes" [[company::attr]] void f() {} #pragma GCC diagnostic pop but that's a mouthful and awkward to use and could also hide typos. In fact, any macro-based solution doesn't seem like a way forward. This patch implements -Wno-attributes=, which takes these arguments: company::attr company:: This option should go well with using @file: the user could have a file containing -Wno-attributes=vendor::attr1,vendor::attr2 and then invoke gcc with '@attrs' or similar. I've also added a new pragma which has the same effect: The pragma along with the new option should help with various static analysis tools. PR c++/101940 gcc/ChangeLog: * attribs.c (struct scoped_attributes): Add a bool member. (lookup_scoped_attribute_spec): Forward declare. (register_scoped_attributes): New bool parameter, defaulted to false. Use it. (handle_ignored_attributes_option): New function. (free_attr_data): New function. (init_attributes): Call handle_ignored_attributes_option. (attr_namespace_ignored_p): New function. (decl_attributes): Check attr_namespace_ignored_p before warning. * attribs.h (free_attr_data): Declare. (register_scoped_attributes): Adjust declaration. (handle_ignored_attributes_option): Declare. (canonicalize_attr_name): New function template. (canonicalize_attr_name): Use it. * common.opt (Wattributes=): New option with a variable. * doc/extend.texi: Document #pragma GCC diagnostic ignored_attributes. * doc/invoke.texi: Document -Wno-attributes=. * opts.c (common_handle_option) <case OPT_Wattributes_>: Handle. * plugin.h (register_scoped_attributes): Adjust declaration. * toplev.c (compile_file): Call free_attr_data. gcc/c-family/ChangeLog: * c-pragma.c (handle_pragma_diagnostic): Handle #pragma GCC diagnostic ignored_attributes. gcc/testsuite/ChangeLog: * c-c++-common/Wno-attributes-1.c: New test. * c-c++-common/Wno-attributes-2.c: New test. * c-c++-common/Wno-attributes-3.c: New test.
