https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117025
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Joseph Myers <js...@gcc.gnu.org>: https://gcc.gnu.org/g:517c9487f8fdc4e4e90252a9365e5823259dc783 commit r16-916-g517c9487f8fdc4e4e90252a9365e5823259dc783 Author: Alejandro Colomar <a...@kernel.org> Date: Thu May 22 01:15:36 2025 +0200 c: Add _Countof operator [PR117025] This operator is similar to sizeof but can only be applied to an array, and returns its number of elements. FUTURE DIRECTIONS: - We should make it work with array parameters to functions, and somehow magically return the number of elements of the array, regardless of it being really a pointer. Link: <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3550.pdf> Link: <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117025> Link: <https://inbox.sourceware.org/gcc/m8s4oqy--...@tutanota.com/T/> Link: <https://inbox.sourceware.org/gcc-patches/20240728141547.302478-1-...@kernel.org/T/#t> Link: <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3313.pdf> Link: <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3325.pdf> Link: <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3369.pdf> Link: <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3469.htm> Link: <https://github.com/llvm/llvm-project/issues/102836> Link: <https://thephd.dev/the-big-array-size-survey-for-c> Link: <https://thephd.dev/the-big-array-size-survey-for-c-results> Link: <https://stackoverflow.com/questions/37538/#57537491> PR c/117025 gcc/ChangeLog: * doc/extend.texi: Document _Countof operator. gcc/c-family/ChangeLog: * c-common.h (enum rid): Add RID_COUNTOF. (c_countof_type): New function prototype. * c-common.def (COUNTOF_EXPR): New tree. * c-common.cc (c_common_reswords): Add RID_COUNTOF entry. (c_countof_type): New function. gcc/c/ChangeLog: * c-tree.h (in_countof): Add global variable declaration. (c_expr_countof_expr): Add function prototype. (c_expr_countof_type): Add function prototype. * c-decl.cc (start_struct, finish_struct): Add support for _Countof. (start_enum, finish_enum): Add support for _Countof. * c-parser.cc (c_parser_sizeof_expression): New macro. (c_parser_countof_expression): New macro. (c_parser_sizeof_or_countof_expression): Rename function and add support for _Countof. (c_parser_unary_expression): Add RID_COUNTOF entry. * c-typeck.cc (in_countof): Add global variable. (build_external_ref): Add support for _Countof. (record_maybe_used_decl): Add support for _Countof. (pop_maybe_used): Add support for _Countof. (is_top_array_vla): New function. (c_expr_countof_expr, c_expr_countof_type): New functions. gcc/testsuite/ChangeLog: * gcc.dg/countof-compile.c: New test. * gcc.dg/countof-vla.c: New test. * gcc.dg/countof-vmt.c: New test. * gcc.dg/countof-zero-compile.c: New test. * gcc.dg/countof-zero.c: New test. * gcc.dg/countof.c: New test. Suggested-by: Xavier Del Campo Romero <xavi....@tutanota.com> Co-authored-by: Martin Uecker <uec...@tugraz.at> Acked-by: "James K. Lowden" <jklow...@schemamania.org> Signed-off-by: Alejandro Colomar <a...@kernel.org>
