https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103649
--- Comment #1 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:6afb8a68a9113897ccf39e40983e042ed90d7aed commit r12-6052-g6afb8a68a9113897ccf39e40983e042ed90d7aed Author: Marek Polacek <pola...@redhat.com> Date: Thu Dec 16 16:29:41 2021 -0500 attribs: Fix wrong error with -Wno-attribute=A::b [PR103649] My patch to implement -Wno-attribute=A::b caused a bogus error when parsing [[foo::bar(1, 2)]]; when -Wno-attributes=foo::bar was specified on the command line, because when we create a fake foo::bar attribute and insert it into our attribute table, it is created with max_length == 0 which doesn't allow any args. That is wrong -- we know nothing about the attribute, so we shouldn't require any specific number of arguments. And since unknown attributes can be rather complex (see for example omp::{directive,sequence}), we must skip parsing their arguments. To that end, I'm using max_length with value -2. Also let's not warn about things like [[vendor::assume(true)]]; because they may have some meaning (this is reminiscent of C++ Portable Assumptions). PR c/103649 gcc/ChangeLog: * attribs.c (handle_ignored_attributes_option): Create the fake attribute with max_length == -2. (attribute_ignored_p): New overloads. * attribs.h (attribute_ignored_p): Declare them. * tree-core.h (struct attribute_spec): Document that max_length can be -2. gcc/c/ChangeLog: * c-decl.c (c_warn_unused_attributes): Don't warn for attribute_ignored_p. * c-parser.c (c_parser_std_attribute): Skip parsing of the attribute arguments when the attribute is ignored. gcc/cp/ChangeLog: * parser.c (cp_parser_declaration): Don't warn for attribute_ignored_p. (cp_parser_std_attribute): Skip parsing of the attribute arguments when the attribute is ignored. gcc/testsuite/ChangeLog: * c-c++-common/Wno-attributes-6.c: New test.
