https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112339
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:533241c6c60bc7c9f7dc47a94e94b5eed1b370e6 commit r14-5265-g533241c6c60bc7c9f7dc47a94e94b5eed1b370e6 Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Nov 9 09:05:54 2023 +0100 attribs: Fix ICE with -Wno-attributes= [PR112339] The following testcase ICEs, because with -Wno-attributes=foo::no_sanitize (but generally any other non-gnu namespace and some gnu well known attribute name within that other namespace) the FEs don't really parse attribute arguments of such attribute, but lookup_attribute_spec is non-NULL with NULL handler and such attributes are added to DECL_ATTRIBUTES or TYPE_ATTRIBUTES and then when e.g. middle-end does lookup_attribute on a particular attribute and expects the attribute to mean something and/or have a particular verified arguments, it can crash when seeing the foreign attribute in there instead. The following patch fixes that by never adding ignored attributes to DECL_ATTRIBUTES/TYPE_ATTRIBUTES, previously that was the case just for attributes in ignored namespace (where lookup_attribute_space returned NULL). We don't really know anything about those attributes, so shouldn't pretend we know something about them, especially when the arguments are error_mark_node or NULL instead of something that would have been parsed. And it would be really weird if we normally ignore say [[clang::unused]] attribute, but when people use -Wno-attributes=clang::unused we actually treated it as gnu::unused. All the user asked for is suppress warnings about that attribute being unknown. The first hunk is just playing safe, I'm worried people could -Wno-attributes=gnu:: and get various crashes with known GNU attributes not being actually parsed and recorded (or worse e.g. when we tweak standard attributes into GNU attributes and we wouldn't add those). The -Wno-attributes= documentation says that it suppresses warning about unknown attributes, so I think -Wno-attributes=gnu:: should prevent warning about say [[gnu::foobarbaz]] attribute, but not about [[gnu::unused]] because the latter is a known attribute. The routine would return true for any scoped attribute in the ignored namespace, with the change it ignores only unknown attributes in ignored namespace, known ones in there will be ignored only if they have max_length of -2 (e.g.. with -Wno-attributes=gnu:: -Wno-attributes=gnu::foobarbaz). 2023-11-09 Jakub Jelinek <ja...@redhat.com> PR c/112339 * attribs.cc (attribute_ignored_p): Only return true for attr_namespace_ignored_p if as is NULL. (decl_attributes): Never add ignored attributes. * c-c++-common/ubsan/Wno-attributes-1.c: New test.
