1*4882a593SmuzhiyunFrom 2e359284497c361e3208501fc70d49b2c54dc4ef Mon Sep 17 00:00:00 2001 2*4882a593SmuzhiyunFrom: Michael Jeanson <mjeanson@efficios.com> 3*4882a593SmuzhiyunDate: Tue, 14 Sep 2021 10:41:08 -0400 4*4882a593SmuzhiyunSubject: [PATCH] Always use '__thread' for Thread local storage except on MSVC 5*4882a593Smuzhiyun 6*4882a593SmuzhiyunUse the GCC extension '__thread' [1] for Thread local storage on all C 7*4882a593Smuzhiyunand C++ compilers except MSVC. 8*4882a593Smuzhiyun 9*4882a593SmuzhiyunWhile C11 and C++11 respectively offer '_Thread_local' and 10*4882a593Smuzhiyun'thread_local' as potentialy faster implementations, they offer no 11*4882a593Smuzhiyunguarantees of compatibility when used in a library interface which might 12*4882a593Smuzhiyunbe used by both C and C++ client code. 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun[1] https://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html 15*4882a593Smuzhiyun 16*4882a593SmuzhiyunChange-Id: If4fe8bcdbda24b21dedf382112bd5c5f836c00c8 17*4882a593SmuzhiyunSigned-off-by: Michael Jeanson <mjeanson@efficios.com> 18*4882a593SmuzhiyunSigned-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun[Retrieved from: 21*4882a593Smuzhiyunhttps://github.com/urcu/userspace-rcu/commit/2e359284497c361e3208501fc70d49b2c54dc4ef] 22*4882a593SmuzhiyunSigned-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com> 23*4882a593Smuzhiyun--- 24*4882a593Smuzhiyun include/urcu/tls-compat.h | 15 +++++++-------- 25*4882a593Smuzhiyun 1 file changed, 7 insertions(+), 8 deletions(-) 26*4882a593Smuzhiyun 27*4882a593Smuzhiyundiff --git a/include/urcu/tls-compat.h b/include/urcu/tls-compat.h 28*4882a593Smuzhiyunindex 25cf375a..a2c94ded 100644 29*4882a593Smuzhiyun--- a/include/urcu/tls-compat.h 30*4882a593Smuzhiyun+++ b/include/urcu/tls-compat.h 31*4882a593Smuzhiyun@@ -35,15 +35,14 @@ extern "C" { 32*4882a593Smuzhiyun #ifdef CONFIG_RCU_TLS 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun /* 35*4882a593Smuzhiyun- * Don't use C++ 'thread_local' on MacOs, the implementation is incompatible 36*4882a593Smuzhiyun- * with C and will result in a link error when accessing an extern variable 37*4882a593Smuzhiyun- * provided by the C library from C++ code. 38*4882a593Smuzhiyun+ * Default to '__thread' on all C and C++ compilers except MSVC. While C11 has 39*4882a593Smuzhiyun+ * '_Thread_local' and C++11 has 'thread_local', only '__thread' seems to have 40*4882a593Smuzhiyun+ * a compatible implementation when linking public extern symbols across 41*4882a593Smuzhiyun+ * language boundaries. 42*4882a593Smuzhiyun+ * 43*4882a593Smuzhiyun+ * For more details, see 'https://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html'. 44*4882a593Smuzhiyun */ 45*4882a593Smuzhiyun-#if defined (__cplusplus) && (__cplusplus >= 201103L) && !defined(__APPLE__) 46*4882a593Smuzhiyun-# define URCU_TLS_STORAGE_CLASS thread_local 47*4882a593Smuzhiyun-#elif defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) 48*4882a593Smuzhiyun-# define URCU_TLS_STORAGE_CLASS _Thread_local 49*4882a593Smuzhiyun-#elif defined (_MSC_VER) 50*4882a593Smuzhiyun+#if defined(_MSC_VER) 51*4882a593Smuzhiyun # define URCU_TLS_STORAGE_CLASS __declspec(thread) 52*4882a593Smuzhiyun #else 53*4882a593Smuzhiyun # define URCU_TLS_STORAGE_CLASS __thread 54