From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 147293858422; Thu, 22 Feb 2024 18:33:48 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 147293858422 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1708626828; bh=1o27CcyOnwXIZmqQwQab9aj5is2HlihP9XoxnU4bNRo=; h=From:To:Subject:Date:In-Reply-To:References:From; b=M6L8L01gX3/m2voPPueMf4B0FfjrTUCYYyUv3GllYk6OzEyDMCeh7Nk2E+D/AQKgv 0lD9W/ThITAwwjauqpBl/Z7/NXPWeGAzqgre2p6E7F96bk6SxEA+Xmz/dIouk3istx l8FhYqQ4jXT7GrXuPoQN59MWQu9C/VXSbAFHp3Hs= From: "cvs-commit at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug preprocessor/114007] gcc chokes on __has_cpp_attribute(clang::unsafe_buffer_usage) Date: Thu, 22 Feb 2024 18:33:47 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: preprocessor X-Bugzilla-Version: 14.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: cvs-commit at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: jakub at gcc dot gnu.org X-Bugzilla-Target-Milestone: 14.0 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114007 --- Comment #27 from GCC Commits --- The master branch has been updated by Jakub Jelinek : https://gcc.gnu.org/g:37127ed975e09813eaa2d1cf1062055fce45dd16 commit r14-9139-g37127ed975e09813eaa2d1cf1062055fce45dd16 Author: Jakub Jelinek Date: Thu Feb 22 19:32:02 2024 +0100 c: Handle scoped attributes in __has*attribute and scoped attribute par= sing changes in -std=3Dc11 etc. modes [PR114007] We aren't able to parse __has_attribute (vendor::attr) (and __has_c_attribute and __has_cpp_attribute) in strict C < C23 modes. While in -std=3Dgnu*= modes or in -std=3Dc23 there is CPP_SCOPE token, in -std=3Dc* (except for -st= d=3Dc23) there are is just a pair of CPP_COLON tokens. The c-lex.cc hunk adds support for that. That leads to a question if we should return 1 or 0 from __has_attribute (gnu::unused) or not, because while [[gnu::unused]] is parsed fine in -std=3Dgnu*/-std=3Dc23 modes (sure, w= ith pedwarn for < C23), we do not parse it at all in -std=3Dc* (except for -std=3Dc23), we only parse [[__extension__ gnu::unused]] there. While the __extension__ in there helps to avoid the pedwarn, I think it is better to be consistent between GNU and strict C < C23 modes and parse [[gnu::unused]] too; on the other side, I think parsing [[__extension__ gnu : : unused]] is too weird and undesirable. So, the following patch adds a flag during preprocessing at the point where we normally create CPP_SCOPE tokens out of 2 consecutive colons on the first CPP_COLON to mark the consecutive case (as we are tight on the bits, I've reused the PURE_ZERO flag, which is used just by the C++ FE and only ever set (both C and C++) on CPP_NUMBER tokens, this new flag has the same value and is only ever used on CPP_COLON tokens) and instead of checking loose_scope_p argument (i.e. whether it is [[__extension__ ...]] or not), it just parses CPP_SCOPE or CPP_COLON with CLONE_SCOPE flag followed by another CPP_COLON the same. The latter will never appear in >=3D C23 or -std=3Dgnu* modes, though guarding its use say with flag_iso && !flag_isoc23 && doesn't really work because the __extension__ case temporarily clears flag_iso flag. This makes the -std=3Dc11 etc. behavior more similar to -std=3Dgnu11 or -std=3Dc23, the only difference I'm aware of are the #define JOIN2(A, B) A##B [[vendor JOIN2(:,:) attr]] [[__extension__ vendor JOIN2(:,:) attr]] cases, which are accepted in the latter modes, but results in error in -std=3Dc11; but the error is during preprocessing that :: doesn't form a valid preprocessing token, which is true, so just don't do that = if you try to have __STRICT_ANSI__ && __STDC_VERSION__ <=3D 201710L compatibility. 2024-02-22 Jakub Jelinek PR c/114007 gcc/ * doc/extend.texi: (__extension__): Remove comments about scope tokens vs. two colons. gcc/c-family/ * c-lex.cc (c_common_has_attribute): Parse 2 CPP_COLONs with the first one with COLON_SCOPE flag the same as CPP_SCOPE. gcc/c/ * c-parser.cc (c_parser_std_attribute): Remove loose_scope_p argument. Instead of checking it, parse 2 CPP_COLONs with the first one w= ith COLON_SCOPE flag the same as CPP_SCOPE. (c_parser_std_attribute_list): Remove loose_scope_p argument, d= on't pass it to c_parser_std_attribute. (c_parser_std_attribute_specifier): Adjust c_parser_std_attribute_list caller. gcc/testsuite/ * gcc.dg/c23-attr-syntax-6.c: Adjust testcase for :: being valid even in -std=3Dc11 even without __extension__ and : : etc. not = being valid anymore even with __extension__. * gcc.dg/c23-attr-syntax-7.c: Likewise. * gcc.dg/c23-attr-syntax-8.c: New test. libcpp/ * include/cpplib.h (COLON_SCOPE): Define to PURE_ZERO. * lex.cc (_cpp_lex_direct): When lexing CPP_COLON with another colon after it, if !CPP_OPTION (pfile, scope) set COLON_SCOPE flag on the first CPP_COLON token.=