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[69.118.112.187]) by smtp.gmail.com with ESMTPSA id cx26-20020a05620a51da00b006fa12a74c53sm3018498qkb.61.2022.11.04.08.05.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Nov 2022 08:05:30 -0700 (PDT) To: gcc-patches@gcc.gnu.org Subject: [PATCH 2/2] libstdc++: Move stream initialization into compiled library [PR44952] Date: Fri, 4 Nov 2022 11:05:25 -0400 Message-Id: <20221104150525.2968778-2-ppalka@redhat.com> X-Mailer: git-send-email 2.38.1.385.g3b08839926 In-Reply-To: <20221104150525.2968778-1-ppalka@redhat.com> References: <20221104150525.2968778-1-ppalka@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-14.3 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_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Patrick Palka via Gcc-patches From: Patrick Palka Reply-To: Patrick Palka Cc: libstdc++@gcc.gnu.org Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Sender: "Gcc-patches" This patch moves the global object for constructing the standard streams out from and into the compiled library on targets that support the init_priority attribute. This means that no longer introduces a separate global constructor in each TU that includes it. We can do this only if the init_priority attribute is supported because we need to force that the stream initialization runs first before any user-defined global initializer in programs that that use a static libstdc++.a. Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look right? Unfortunately I don't have access to a system that truly doesn't support init priorities, so I instead tested that situation by artificially disabling the init_priority attribute on x86_64. PR libstdc++/44952 PR libstdc++/98108 libstdc++-v3/ChangeLog: * include/bits/c++config (_GLIBCXX_HAS_ATTRIBUTE): Define. (_GLIBCXX_HAVE_ATTRIBUTE_INIT_PRIORITY): Define. * include/std/iostream (__ioinit): Define only if init_priority attribute isn't usable. * src/c++98/ios_init.cc (__ioinit): Define here instead if the init_priority is usable. * src/c++98/ios_base_init.h: New file. --- libstdc++-v3/include/bits/c++config | 12 ++++++++++++ libstdc++-v3/include/std/iostream | 4 ++++ libstdc++-v3/src/c++98/ios_base_init.h | 9 +++++++++ libstdc++-v3/src/c++98/ios_init.cc | 4 ++++ 4 files changed, 29 insertions(+) create mode 100644 libstdc++-v3/src/c++98/ios_base_init.h diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config index 50406066afe..f93076191d9 100644 --- a/libstdc++-v3/include/bits/c++config +++ b/libstdc++-v3/include/bits/c++config @@ -837,6 +837,18 @@ namespace __gnu_cxx #undef _GLIBCXX_HAS_BUILTIN +#ifdef __has_attribute +# define _GLIBCXX_HAS_ATTRIBUTE(B) __has_attribute(B) +#else +# define _GLIBCXX_HAS_ATTRIBUTE(B) 0 +#endif + +#if _GLIBCXX_HAS_ATTRIBUTE(init_priority) +# define _GLIBCXX_HAVE_ATTRIBUTE_INIT_PRIORITY 1 +#endif + +#undef _GLIBCXX_HAS_ATTRIBUTE + // Mark code that should be ignored by the compiler, but seen by Doxygen. #define _GLIBCXX_DOXYGEN_ONLY(X) diff --git a/libstdc++-v3/include/std/iostream b/libstdc++-v3/include/std/iostream index 70318a45891..5eaa9755d9a 100644 --- a/libstdc++-v3/include/std/iostream +++ b/libstdc++-v3/include/std/iostream @@ -73,7 +73,11 @@ _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 (see src/c++98/ios_init.cc). +#if !_GLIBCXX_HAVE_ATTRIBUTE_INIT_PRIORITY static ios_base::Init __ioinit; +#endif _GLIBCXX_END_NAMESPACE_VERSION } // namespace diff --git a/libstdc++-v3/src/c++98/ios_base_init.h b/libstdc++-v3/src/c++98/ios_base_init.h new file mode 100644 index 00000000000..f3087d1da3c --- /dev/null +++ b/libstdc++-v3/src/c++98/ios_base_init.h @@ -0,0 +1,9 @@ +// This is only in a header so we can use the system_header pragma, +// to suppress the warning caused by using a reserved init_priority. +#pragma GCC system_header + +#if !_GLIBCXX_HAVE_ATTRIBUTE_INIT_PRIORITY +# error "This file should not be included for this build" +#endif + +static ios_base::Init __ioinit __attribute__((init_priority(90))); diff --git a/libstdc++-v3/src/c++98/ios_init.cc b/libstdc++-v3/src/c++98/ios_init.cc index 1b5132f1c2d..954fa9f29cf 100644 --- a/libstdc++-v3/src/c++98/ios_init.cc +++ b/libstdc++-v3/src/c++98/ios_init.cc @@ -75,6 +75,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION extern wostream wclog; #endif +#if _GLIBCXX_HAVE_ATTRIBUTE_INIT_PRIORITY +# include "ios_base_init.h" +#endif + ios_base::Init::Init() { if (__gnu_cxx::__exchange_and_add_dispatch(&_S_refcount, 1) == 0)