Author: Aaron Ballman Date: 2025-05-28T06:41:01-04:00 New Revision: 5ab944a8c6a213beb96f3747a441b02e497732e4
URL: https://github.com/llvm/llvm-project/commit/5ab944a8c6a213beb96f3747a441b02e497732e4 DIFF: https://github.com/llvm/llvm-project/commit/5ab944a8c6a213beb96f3747a441b02e497732e4.diff LOG: [C2y] Add stdcountof.h (#140890) WG14 N3469 changed _Lengthof to _Countof but it also introduced the <stdcountof.h> header to expose a macro with a non-ugly identifier. GCC vends this header as part of the compiler implementation, so Clang should do the same. Suggested-by: Alejandro Colomar <a...@kernel.org> Added: clang/lib/Headers/stdcountof.h Modified: clang/docs/ReleaseNotes.rst clang/lib/Headers/CMakeLists.txt clang/lib/Headers/module.modulemap clang/lib/Lex/ModuleMap.cpp clang/lib/Lex/PPDirectives.cpp clang/test/C/C2y/n3469.c clang/test/Modules/Inputs/builtin-headers/system-modules.modulemap clang/test/Modules/builtin-headers.mm Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index ee74431cf33a7..c83f135da541c 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -251,7 +251,9 @@ C2y Feature Support a conforming extension in earlier C language modes, but not in C++ language modes (``std::extent`` and ``std::size`` already provide the same functionality but with more granularity). The feature can be tested via - ``__has_feature(c_countof)`` or ``__has_extension(c_countof)``. + ``__has_feature(c_countof)`` or ``__has_extension(c_countof)``. This also + adds the ``<stdcountof.h>`` header file which exposes the ``countof`` macro + which expands to ``_Countof``. C23 Feature Support ^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Headers/CMakeLists.txt b/clang/lib/Headers/CMakeLists.txt index 53219dc932587..24f5327b07dda 100644 --- a/clang/lib/Headers/CMakeLists.txt +++ b/clang/lib/Headers/CMakeLists.txt @@ -18,6 +18,7 @@ set(core_files __stdarg_va_list.h stdatomic.h stdbool.h + stdcountof.h stdckdint.h stddef.h __stddef_header_macro.h diff --git a/clang/lib/Headers/module.modulemap b/clang/lib/Headers/module.modulemap index dcaf09e8f2c55..35897a3ed0e79 100644 --- a/clang/lib/Headers/module.modulemap +++ b/clang/lib/Headers/module.modulemap @@ -231,6 +231,11 @@ module _Builtin_stdbool [system] { export * } +module _Builtin_stdcountof [system] { + header "stdcountof.h" + export * +} + module _Builtin_stddef [system] { textual header "stddef.h" diff --git a/clang/lib/Headers/stdcountof.h b/clang/lib/Headers/stdcountof.h new file mode 100644 index 0000000000000..5714e6d6ff860 --- /dev/null +++ b/clang/lib/Headers/stdcountof.h @@ -0,0 +1,15 @@ +/*===---- stdcountof.h - Standard header for countof -----------------------=== + * + * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. + * See https://llvm.org/LICENSE.txt for license information. + * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception + * + *===-----------------------------------------------------------------------=== + */ + +#ifndef __STDCOUNTOF_H +#define __STDCOUNTOF_H + +#define countof _Countof + +#endif /* __STDCOUNTOF_H */ diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp index c088e4eecb3fb..637a08fe4dcdb 100644 --- a/clang/lib/Lex/ModuleMap.cpp +++ b/clang/lib/Lex/ModuleMap.cpp @@ -258,6 +258,7 @@ static bool isBuiltinHeaderName(StringRef FileName) { .Case("stdarg.h", true) .Case("stdatomic.h", true) .Case("stdbool.h", true) + .Case("stdcountof.h", true) .Case("stddef.h", true) .Case("stdint.h", true) .Case("tgmath.h", true) diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp index b2a8459d6b9cc..68f9ca9cb4d40 100644 --- a/clang/lib/Lex/PPDirectives.cpp +++ b/clang/lib/Lex/PPDirectives.cpp @@ -252,8 +252,8 @@ static bool warnByDefaultOnWrongCase(StringRef Include) { .Cases("assert.h", "complex.h", "ctype.h", "errno.h", "fenv.h", true) .Cases("float.h", "inttypes.h", "iso646.h", "limits.h", "locale.h", true) .Cases("math.h", "setjmp.h", "signal.h", "stdalign.h", "stdarg.h", true) - .Cases("stdatomic.h", "stdbool.h", "stdckdint.h", "stddef.h", true) - .Cases("stdint.h", "stdio.h", "stdlib.h", "stdnoreturn.h", true) + .Cases("stdatomic.h", "stdbool.h", "stdckdint.h", "stdcountof.h", true) + .Cases("stddef.h", "stdint.h", "stdio.h", "stdlib.h", "stdnoreturn.h", true) .Cases("string.h", "tgmath.h", "threads.h", "time.h", "uchar.h", true) .Cases("wchar.h", "wctype.h", true) diff --git a/clang/test/C/C2y/n3469.c b/clang/test/C/C2y/n3469.c index 3d9ac8e6411e9..4660596614075 100644 --- a/clang/test/C/C2y/n3469.c +++ b/clang/test/C/C2y/n3469.c @@ -1,9 +1,9 @@ -// RUN: %clang_cc1 -fsyntax-only -std=c2y -verify %s +// RUN: %clang_cc1 -fsyntax-only -std=c2y -verify -ffreestanding %s /* WG14 N3469: Clang 21 * The Big Array Size Survey * - * This renames _Lengthof to _Countof. + * This renames _Lengthof to _Countof and introduces the stdcountof.h header. */ void test() { @@ -12,3 +12,12 @@ void test() { expected-error {{expected expression}} } +#ifdef countof +#error "why is countof defined as a macro?" +#endif + +#include <stdcountof.h> + +#ifndef countof +#error "why is countof not defined as a macro?" +#endif diff --git a/clang/test/Modules/Inputs/builtin-headers/system-modules.modulemap b/clang/test/Modules/Inputs/builtin-headers/system-modules.modulemap index 0161ff80fe618..186965177caaf 100644 --- a/clang/test/Modules/Inputs/builtin-headers/system-modules.modulemap +++ b/clang/test/Modules/Inputs/builtin-headers/system-modules.modulemap @@ -49,6 +49,11 @@ module cstd [system] [no_undeclared_includes] { export * } + module stdcountof { + header "stdcountof.h" + export * + } + module stddef { header "stddef.h" export * diff --git a/clang/test/Modules/builtin-headers.mm b/clang/test/Modules/builtin-headers.mm index 4c9ddec4e99c2..ad2d66ae38dfd 100644 --- a/clang/test/Modules/builtin-headers.mm +++ b/clang/test/Modules/builtin-headers.mm @@ -17,6 +17,7 @@ @import _Builtin_stdarg; @import _Builtin_stdatomic; @import _Builtin_stdbool; +@import _Builtin_stdcountof; @import _Builtin_stddef; @import _Builtin_stdint; @import _Builtin_stdnoreturn; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
