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| author | Alexandre Oliva <oliva@adacore.com> | 2023-12-07 00:38:14 -0300 |
|---|---|---|
| committer | Alexandre Oliva <oliva@gnu.org> | 2023-12-07 00:38:14 -0300 |
| commit | 3d0f3382fa7b5677f35a9becf75ac436cd7eda7b (patch) | |
| tree | 9eb48f2f06f89cd058e5c4a5ad0da3aa39307ec9 | |
| parent | 3b096bc439cc4499b2caca4e2772adecaabc20c8 (diff) | |
| download | gcc-3d0f3382fa7b5677f35a9becf75ac436cd7eda7b.zip gcc-3d0f3382fa7b5677f35a9becf75ac436cd7eda7b.tar.gz gcc-3d0f3382fa7b5677f35a9becf75ac436cd7eda7b.tar.bz2 | |
libsupc++: try cxa_thread_atexit_impl at runtime
g++.dg/tls/thread_local-order2.C fails when the toolchain is built for
a platform that lacks __cxa_thread_atexit_impl, even if the program is
built and run using that toolchain on a (later) platform that offers
__cxa_thread_atexit_impl.
This patch adds runtime testing for __cxa_thread_atexit_impl on select
platforms (GNU variants, for starters) that support weak symbols.
for libstdc++-v3/ChangeLog
PR libstdc++/112858
* config/os/gnu-linux/os_defines.h
(_GLIBCXX_MAY_HAVE___CXA_THREAD_ATEXIT_IMPL): Define.
* libsupc++/atexit_thread.cc [__GXX_WEAK__ &&
_GLIBCXX_MAY_HAVE___CXA_THREAD_ATEXIT_IMPL]
(__cxa_thread_atexit): Add dynamic detection of
__cxa_thread_atexit_impl.
| -rw-r--r-- | libstdc++-v3/config/os/gnu-linux/os_defines.h | 5 | ||||
| -rw-r--r-- | libstdc++-v3/libsupc++/atexit_thread.cc | 23 |
2 files changed, 27 insertions, 1 deletions
diff --git a/libstdc++-v3/config/os/gnu-linux/os_defines.h b/libstdc++-v3/config/os/gnu-linux/os_defines.h index 8731703..a2e4bae 100644 --- a/libstdc++-v3/config/os/gnu-linux/os_defines.h +++ b/libstdc++-v3/config/os/gnu-linux/os_defines.h @@ -60,6 +60,11 @@ # define _GLIBCXX_HAVE_FLOAT128_MATH 1 #endif +// Enable __cxa_thread_atexit to rely on a (presumably libc-provided) +// __cxa_thread_atexit_impl, if it happens to be defined, even if +// configure couldn't find it during the build. +#define _GLIBCXX_MAY_HAVE___CXA_THREAD_ATEXIT_IMPL 1 + #ifdef __linux__ // The following libpthread properties only apply to Linux, not GNU/Hurd. diff --git a/libstdc++-v3/libsupc++/atexit_thread.cc b/libstdc++-v3/libsupc++/atexit_thread.cc index 9346d50..2842334 100644 --- a/libstdc++-v3/libsupc++/atexit_thread.cc +++ b/libstdc++-v3/libsupc++/atexit_thread.cc @@ -138,11 +138,32 @@ namespace { } } +#if __GXX_WEAK__ && _GLIBCXX_MAY_HAVE___CXA_THREAD_ATEXIT_IMPL +extern "C" +int __attribute__ ((__weak__)) +__cxa_thread_atexit_impl (void (_GLIBCXX_CDTOR_CALLABI *func) (void *), + void *arg, void *d); +#endif + +// ??? We can't make it an ifunc, can we? extern "C" int __cxxabiv1::__cxa_thread_atexit (void (_GLIBCXX_CDTOR_CALLABI *dtor)(void *), - void *obj, void */*dso_handle*/) + void *obj, [[maybe_unused]] void *dso_handle) _GLIBCXX_NOTHROW { +#if __GXX_WEAK__ && _GLIBCXX_MAY_HAVE___CXA_THREAD_ATEXIT_IMPL + if (__cxa_thread_atexit_impl) + // Rely on a (presumably libc-provided) __cxa_thread_atexit_impl, + // if it happens to be defined, even if configure couldn't find it + // during the build. _GLIBCXX_MAY_HAVE___CXA_THREAD_ATEXIT_IMPL + // may be defined e.g. in os_defines.h on platforms where some + // versions of libc have a __cxa_thread_atexit_impl definition, + // but whose earlier versions didn't. This enables programs build + // by toolchains compatible with earlier libc versions to still + // benefit from a libc-provided __cxa_thread_atexit_impl. + return __cxa_thread_atexit_impl (dtor, obj, dso_handle); +#endif + // Do this initialization once. if (__gthread_active_p ()) { |