From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id 144CC3857C46; Tue, 1 Dec 2020 14:15:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 144CC3857C46 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r11-5611] libstdc++: Simplify detection of built-in functions X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/master X-Git-Oldrev: 6ea5a23766b8077a503362c4fa6f51de92669c11 X-Git-Newrev: 6aa12274007bccbae2691a9d336c37fe167bb535 Message-Id: <20201201141505.144CC3857C46@sourceware.org> Date: Tue, 1 Dec 2020 14:15:05 +0000 (GMT) X-BeenThere: libstdc++-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Dec 2020 14:15:05 -0000 https://gcc.gnu.org/g:6aa12274007bccbae2691a9d336c37fe167bb535 commit r11-5611-g6aa12274007bccbae2691a9d336c37fe167bb535 Author: Jonathan Wakely Date: Tue Dec 1 14:14:18 2020 +0000 libstdc++: Simplify detection of built-in functions This fixes a regression affecting the Intel compiler. Because that compiler defines __GNUC__ to match whatever version of GCC it finds on the host system, it might claim to be a brand new GCC despite not actually supporting all the built-ins that the latest GCC supports. This means the config checks for __GNUC__ don't work. Most recently this broke when r11-3569-g73ae6eb572515ad627b575a7fbdfdd47a4368e1c switched us from using __is_same_as to __is_same when __GNUC__ >= 11. Because __has_builtin is supported by all of GCC, Clang, and Intel we can use that to reliably detect whether a given built-in is supported, instead of hardcoding anything based on __GNUC__. The big caveat is that for versions of Clang <= 9.0.0 and for (as far as I can tell) all released versions of Intel icc, __has_builtin only evaluates to true for built-ins with a name starting "__builtin_". For __is_aggregate, __is_same, and __has_unique_object_representations it's necessary to use __is_identifier to check if it's a valid identifeir token instead. The solution used in this patch is to define _GLIBCXX_HAS_BUILTIN and use that instead of using __has_builtin directly. For compilers that define __is_identifier as well as __has_builtin we use both, so that if __has_builtin evaluates to false we try again using !__is_identifier. libstdc++-v3/ChangeLog: * include/bits/c++config (_GLIBCXX_HAS_BUILTIN): Define macro to work around different implementations of __has_builtin. (_GLIBCXX_HAVE_BUILTIN_HAS_UNIQ_OBJ_REP) (_GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE) (_GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED) (_GLIBCXX_HAVE_BUILTIN_IS_SAME, _GLIBCXX_HAVE_BUILTIN_LAUNDER): Define using _GLIBCXX_HAS_BUILTIN. Diff: --- libstdc++-v3/include/bits/c++config | 51 +++++++++++++++++++------------------ 1 file changed, 26 insertions(+), 25 deletions(-) diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config index 2e6c880ad95..27302ed392e 100644 --- a/libstdc++-v3/include/bits/c++config +++ b/libstdc++-v3/include/bits/c++config @@ -653,35 +653,36 @@ namespace std #define _GLIBCXX_USE_FLOAT128 #endif -#if __GNUC__ >= 7 -// Assume these are available if the compiler claims to be a recent GCC: +#ifdef __has_builtin +# ifdef __is_identifier +// Intel and older Clang require !__is_identifier for some built-ins: +# define _GLIBCXX_HAS_BUILTIN(B) __has_builtin(B) || ! __is_identifier(B) +# else +# define _GLIBCXX_HAS_BUILTIN(B) __has_builtin(B) +# endif +#endif + +#if _GLIBCXX_HAS_BUILTIN(__has_unique_object_representations) # define _GLIBCXX_HAVE_BUILTIN_HAS_UNIQ_OBJ_REP 1 +#endif + +#if _GLIBCXX_HAS_BUILTIN(__is_aggregate) # define _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE 1 -# define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1 -# if __GNUC__ >= 9 -# define _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED 1 -# endif -# if __GNUC__ >= 11 -# define _GLIBCXX_HAVE_BUILTIN_IS_SAME 1 -# endif -#elif defined(__is_identifier) && defined(__has_builtin) -// For non-GNU compilers: -# if ! __is_identifier(__has_unique_object_representations) -# define _GLIBCXX_HAVE_BUILTIN_HAS_UNIQ_OBJ_REP 1 -# endif -# if ! __is_identifier(__is_aggregate) -# define _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE 1 -# endif -# if __has_builtin(__builtin_launder) -# define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1 -# endif -# if __has_builtin(__builtin_is_constant_evaluated) +#endif + +#if _GLIBCXX_HAS_BUILTIN(__builtin_is_constant_evaluated) # define _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED 1 -# endif -# if ! __is_identifier(__is_same) +#endif + +#if _GLIBCXX_HAS_BUILTIN(__is_same) # define _GLIBCXX_HAVE_BUILTIN_IS_SAME 1 -# endif -#endif // GCC +#endif + +#if _GLIBCXX_HAS_BUILTIN(__builtin_launder) +# define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1 +#endif + +#undef _GLIBCXX_HAS_BUILTIN #if _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED # define __glibcxx_assert_1(_Condition) \