From patchwork Thu Nov 21 13:21:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Emilio_Cobos_=C3=81lvarez?= X-Patchwork-Id: 36089 Received: (qmail 1264 invoked by alias); 21 Nov 2019 13:23:23 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 1256 invoked by uid 89); 21 Nov 2019 13:23:23 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-23.2 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, SPF_HELO_PASS, SPF_PASS autolearn=ham version=3.3.1 spammy=HAuthentication-Results:dis, HAuthentication-Results:sk:mail.em, H*Ad:D*io, HContent-Transfer-Encoding:8bit X-HELO: emiliocobos.net From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= Authentication-Results: mail.emiliocobos.net; dmarc=none (p=none dis=none) header.from=crisal.io To: Florian Weimer , libc-alpha@sourceware.org Cc: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= Subject: [PATCH v2] libc: Don't use a custom wrapper macro around __has_include. Date: Thu, 21 Nov 2019 14:21:01 +0100 Message-Id: <20191121132101.84999-1-emilio@crisal.io> In-Reply-To: <875zjdo045.fsf@oldenburg2.str.redhat.com> References: <875zjdo045.fsf@oldenburg2.str.redhat.com> MIME-Version: 1.0 This causes issues when using clang with -frewrite-includes to e.g., submit the translation unit to a distributed compiler. In my case, I was building Firefox using sccache. See [1] for a reduced test-case since I initially thought this was a clang bug, and [2] for more context. Apparently doing this is invalid C++ per [cpp.cond], which mentions [3]: > The #ifdef and #ifndef directives, and the defined conditional inclusion > operator, shall treat __has_include and __has_cpp_attribute as if they > were the names of defined macros. The identifiers __has_include and > __has_cpp_attribute shall not appear in any context not mentioned in this > subclause. [1]: https://bugs.llvm.org/show_bug.cgi?id=43982 [2]: https://bugs.llvm.org/show_bug.cgi?id=37990 [3]: http://eel.is/c++draft/cpp.cond#7.sentence-2 --- misc/sys/cdefs.h | 8 -------- sysdeps/unix/sysv/linux/bits/statx.h | 12 +++++++----- 2 files changed, 7 insertions(+), 13 deletions(-) diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h index abcb0d5e3c..467dbd9547 100644 --- a/misc/sys/cdefs.h +++ b/misc/sys/cdefs.h @@ -412,14 +412,6 @@ # define __glibc_has_attribute(attr) 0 #endif -#ifdef __has_include -/* Do not use a function-like macro, so that __has_include can inhibit - macro expansion. */ -# define __glibc_has_include __has_include -#else -# define __glibc_has_include(header) 0 -#endif - #if (!defined _Noreturn \ && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \ && !__GNUC_PREREQ (4,7)) diff --git a/sysdeps/unix/sysv/linux/bits/statx.h b/sysdeps/unix/sysv/linux/bits/statx.h index ff3f2e8973..2015c8262e 100644 --- a/sysdeps/unix/sysv/linux/bits/statx.h +++ b/sysdeps/unix/sysv/linux/bits/statx.h @@ -26,11 +26,13 @@ /* Use "" to work around incorrect macro expansion of the __has_include argument (GCC PR 80005). */ -#if __glibc_has_include ("linux/stat.h") -# include "linux/stat.h" -# ifdef STATX_TYPE -# define __statx_timestamp_defined 1 -# define __statx_defined 1 +#ifdef __has_include +# if __has_include ("linux/stat.h") +# include "linux/stat.h" +# ifdef STATX_TYPE +# define __statx_timestamp_defined 1 +# define __statx_defined 1 +# endif # endif #endif