From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id B02063858D38 for ; Fri, 30 Jun 2023 14:11:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org B02063858D38 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688134293; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=NKW2jazhMtZ1T38orYUNl2fAvrhsF5dcknolyFZ9zb0=; b=VExplDxZK7y4eYrfIhg5B1iuRJ4nU23Uc0Y5u79OsdhWVNpWnkg0cWW6HwC1R6HT/rupR8 VC5Jou6lPgpLNpRqHLwDNICA3ZM6AAo/bVw1NJ0aVWOc2GAkGXoOS/TQh+ujTsjk/MgcJu W5NAdjxnYyOMC/Mca+Zt+1lSP1Vqqcw= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-3-3ZfCu70dOK-u-82_hqTOdQ-1; Fri, 30 Jun 2023 10:11:32 -0400 X-MC-Unique: 3ZfCu70dOK-u-82_hqTOdQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BDA7A3C11A07; Fri, 30 Jun 2023 14:11:31 +0000 (UTC) Received: from localhost (unknown [10.42.28.54]) by smtp.corp.redhat.com (Postfix) with ESMTP id 853BDC00049; Fri, 30 Jun 2023 14:11:31 +0000 (UTC) From: Jonathan Wakely To: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org Cc: Patrick Palka Subject: [PATCH] libstdc++: Fix iostream init for Clang on darwin [PR110432] Date: Fri, 30 Jun 2023 15:10:56 +0100 Message-ID: <20230630141131.716948-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Tested x86_64-linux. Patrick, PTAL. -- >8 -- The __has_attribute(init_priority) check in is true for Clang on darwin, which means that user code including thinks the library will initialize the global streams. However, when libstdc++ is built by GCC on darwin, the __has_attribute(init_priority) check is false, which means that the library thinks that user code will do the initialization when is included. This means that the initialization is never done. Add an autoconf check so that the header and the library both make their decision based on the static properties of GCC at build time, with a consistent outcome. As a belt and braces check, also do the initialization in if the compiler including that header doesn't support the attribute (even if the library also containers the initialization). This might result in redundant initialization done in , but ensures the initialization happens somewhere if there's any doubt about the attribute working correctly due to missing linker support. libstdc++-v3/ChangeLog: PR libstdc++/110432 * acinclude.m4 (GLIBCXX_CHECK_INIT_PRIORITY): New. * config.h.in: Regenerate. * configure: Regenerate. * configure.ac: Use GLIBCXX_CHECK_INIT_PRIORITY. * include/std/iostream: * src/c++98/ios_base_init.h: Use new autoconf macro instead of __has_attribute. --- libstdc++-v3/acinclude.m4 | 27 ++++++++++++++ libstdc++-v3/config.h.in | 3 ++ libstdc++-v3/configure | 51 ++++++++++++++++++++++++++ libstdc++-v3/configure.ac | 3 ++ libstdc++-v3/include/std/iostream | 2 +- libstdc++-v3/src/c++98/ios_base_init.h | 2 +- 6 files changed, 86 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 277ae10e031..823832f97d4 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -5680,6 +5680,33 @@ AC_DEFUN([GLIBCXX_CHECK_ALIGNAS_CACHELINE], [ AC_LANG_RESTORE ]) +dnl +dnl Check whether iostream initialization should be done in the library, +dnl using the init_priority attribute. +dnl +dnl Defines: +dnl _GLIBCXX_USE_INIT_PRIORITY_ATTRIBUTE if GCC supports the init_priority +dnl attribute for the target. +dnl +AC_DEFUN([GLIBCXX_CHECK_INIT_PRIORITY], [ +AC_LANG_SAVE + AC_LANG_CPLUSPLUS + + AC_MSG_CHECKING([whether init_priority attribute is supported]) + AC_TRY_COMPILE(, [ + #if ! __has_attribute(init_priority) + #error init_priority not supported + #endif + ], [ac_init_priority=yes], [ac_init_priority=no]) + if test "$ac_init_priority" = yes; then + AC_DEFINE_UNQUOTED(_GLIBCXX_USE_INIT_PRIORITY_ATTRIBUTE, 1, + [Define if init_priority should be used for iostream initialization.]) + fi + AC_MSG_RESULT($ac_init_priority) + + AC_LANG_RESTORE +]) + # Macros from the top-level gcc directory. m4_include([../config/gc++filt.m4]) m4_include([../config/tls.m4]) diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac index 9770c178767..fc0f2522027 100644 --- a/libstdc++-v3/configure.ac +++ b/libstdc++-v3/configure.ac @@ -550,6 +550,9 @@ GLIBCXX_ZONEINFO_DIR # For src/c++11/shared_ptr.cc alignment. GLIBCXX_CHECK_ALIGNAS_CACHELINE +# For using init_priority in ios_init.cc +GLIBCXX_CHECK_INIT_PRIORITY + # Define documentation rules conditionally. # See if makeinfo has been installed and is modern enough diff --git a/libstdc++-v3/include/std/iostream b/libstdc++-v3/include/std/iostream index cfd124dcf43..ec337cf89dd 100644 --- a/libstdc++-v3/include/std/iostream +++ b/libstdc++-v3/include/std/iostream @@ -75,7 +75,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // For construction of filebuffers for cout, cin, cerr, clog et. al. // When the init_priority attribute is usable, we do this initialization // in the compiled library instead (src/c++98/globals_io.cc). -#if !__has_attribute(__init_priority__) +#if !(_GLIBCXX_USE_INIT_PRIORITY_ATTRIBUTE && __has_attribute(init_priority)) static ios_base::Init __ioinit; #elif defined(_GLIBCXX_SYMVER_GNU) __extension__ __asm (".globl _ZSt21ios_base_library_initv"); diff --git a/libstdc++-v3/src/c++98/ios_base_init.h b/libstdc++-v3/src/c++98/ios_base_init.h index b600ec3298e..f7edfc84625 100644 --- a/libstdc++-v3/src/c++98/ios_base_init.h +++ b/libstdc++-v3/src/c++98/ios_base_init.h @@ -8,6 +8,6 @@ // constructor when statically linking with libstdc++.a), instead of // doing so in (each TU that includes) . // This needs to be done in the same TU that defines the stream objects. -#if __has_attribute(init_priority) +#if _GLIBCXX_USE_INIT_PRIORITY_ATTRIBUTE static ios_base::Init __ioinit __attribute__((init_priority(90))); #endif -- 2.41.0