From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id 4BA233858D38; Fri, 30 Jun 2023 14:37:19 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4BA233858D38 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1688135839; bh=LmltHmLMjP322lbXDsRqTz/hZLp3fnMRc19Q4i9Nig8=; h=From:To:Subject:Date:From; b=FAdqTxFvNmNXO4Tv5TZ0ZxIu/ciAoZEHDVaI/kZGmYVkQ6VkiSbU/RJE8EEw6XxRy 1vMF+Lx7j5iPAByE2e82i6xo5EYnD8Ue6qIk+IgMHzaiJ7O/iZoDwA7tdTN1VvlfHQ F+nrgoI1VH2mwrtLdUcsx7E+YFvyku0cOArNlXBk= 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 r14-2221] libstdc++: Fix iostream init for Clang on darwin [PR110432] X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/master X-Git-Oldrev: d083c8c808cae2c7acb46117374bb047b4c3afce X-Git-Newrev: fe2651affa8c15624188bfd062fb894648743431 Message-Id: <20230630143719.4BA233858D38@sourceware.org> Date: Fri, 30 Jun 2023 14:37:19 +0000 (GMT) List-Id: https://gcc.gnu.org/g:fe2651affa8c15624188bfd062fb894648743431 commit r14-2221-gfe2651affa8c15624188bfd062fb894648743431 Author: Jonathan Wakely Date: Fri Jun 30 11:07:35 2023 +0100 libstdc++: Fix iostream init for Clang on darwin [PR110432] 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: Use new autoconf macro as well as __has_attribute. * src/c++98/ios_base_init.h: Use new autoconf macro instead of __has_attribute. Reviewed-by: Patrick Palka Diff: --- 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 | 3 +- libstdc++-v3/src/c++98/ios_base_init.h | 2 +- 6 files changed, 87 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/config.h.in b/libstdc++-v3/config.h.in index e156650792e..91eca6ef608 100644 --- a/libstdc++-v3/config.h.in +++ b/libstdc++-v3/config.h.in @@ -994,6 +994,9 @@ /* Define if get_nprocs is available in . */ #undef _GLIBCXX_USE_GET_NPROCS +/* Define if init_priority should be used for iostream initialization. */ +#undef _GLIBCXX_USE_INIT_PRIORITY_ATTRIBUTE + /* Define if LFS support is available. */ #undef _GLIBCXX_USE_LFS diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure index 98568ae0c30..c8d55083cd7 100755 --- a/libstdc++-v3/configure +++ b/libstdc++-v3/configure @@ -73496,6 +73496,57 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu +# For using init_priority in ios_init.cc + + + ac_ext=cpp +ac_cpp='$CXXCPP $CPPFLAGS' +ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5' +ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5' +ac_compiler_gnu=$ac_cv_cxx_compiler_gnu + + + { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether init_priority attribute is supported" >&5 +$as_echo_n "checking whether init_priority attribute is supported... " >&6; } + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ + +int +main () +{ + + #if ! __has_attribute(init_priority) + #error init_priority not supported + #endif + + ; + return 0; +} +_ACEOF +if ac_fn_cxx_try_compile "$LINENO"; then : + ac_init_priority=yes +else + ac_init_priority=no +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext + if test "$ac_init_priority" = yes; then + +cat >>confdefs.h <<_ACEOF +#define _GLIBCXX_USE_INIT_PRIORITY_ATTRIBUTE 1 +_ACEOF + + fi + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_init_priority" >&5 +$as_echo "$ac_init_priority" >&6; } + + ac_ext=c +ac_cpp='$CPP $CPPFLAGS' +ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5' +ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5' +ac_compiler_gnu=$ac_cv_c_compiler_gnu + + + # Define documentation rules conditionally. # See if makeinfo has been installed and is modern enough 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..0abf7445f58 100644 --- a/libstdc++-v3/include/std/iostream +++ b/libstdc++-v3/include/std/iostream @@ -75,7 +75,8 @@ _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