From 828daae9085c94414170fa037ab6e6a224a4ea0c Mon Sep 17 00:00:00 2001 From: Fabrice Fontaine Date: Fri, 5 Nov 2021 10:31:35 +0100 Subject: [PATCH] package/liburcu: fix build with gcc 4.8 Fix the following lttng-tools build failure raised since bump of liburcu to version 0.13.0 in commit 9cedbcf494e647371f92368014d31091848772bb and https://github.com/urcu/userspace-rcu/commit/109267f653502cf5ef5ada5d098167b9726daa2d: In file included from ../../../src/common/error.h:16:0, from directory-handle.c:9: ../../../src/common/error.h:44:25: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'struct' extern DECLARE_URCU_TLS(struct log_time, error_log_time); ^ This is fixed by upstream 0003-Always-use-__thread-for-Thread-local-storage-except-on-MSVC.patch. Also include upstream 0002-fix-don-t-use-C-thread_local-on-MacOs.patch to avoid conflicts. Fixes: - http://autobuild.buildroot.org/results/70d645593c9e164d0d044da1b0128cda9c96e830 Signed-off-by: Fabrice Fontaine Signed-off-by: Arnout Vandecappelle (Essensium/Mind) --- ...ix-don-t-use-C-thread_local-on-MacOs.patch | 41 ++++++++++++++ ...-Thread-local-storage-except-on-MSVC.patch | 53 +++++++++++++++++++ 2 files changed, 94 insertions(+) create mode 100644 package/liburcu/0002-fix-don-t-use-C-thread_local-on-MacOs.patch create mode 100644 package/liburcu/0003-Always-use-__thread-for-Thread-local-storage-except-on-MSVC.patch diff --git a/package/liburcu/0002-fix-don-t-use-C-thread_local-on-MacOs.patch b/package/liburcu/0002-fix-don-t-use-C-thread_local-on-MacOs.patch new file mode 100644 index 0000000000..002df34d70 --- /dev/null +++ b/package/liburcu/0002-fix-don-t-use-C-thread_local-on-MacOs.patch @@ -0,0 +1,41 @@ +From e915ab84fd0c02d37504f3eb1e1f3be93ea6dc37 Mon Sep 17 00:00:00 2001 +From: Michael Jeanson +Date: Thu, 9 Sep 2021 12:11:16 -0400 +Subject: [PATCH] fix: don't use C++ thread_local on MacOs + +Recent versions of Apple's clang++ do support 'thread_local' but the +implementation generates additional helper symbols. This is a problem +when accessing an extern TLS variable in a C++ compile unit that is +provided by a C library that doesn't have those extra symbols. + +Fallback to using '__thread' on MacOs. + +Change-Id: I87cb5b3c9293f7bf66f7115f453b546dd793a449 +Signed-off-by: Michael Jeanson +Signed-off-by: Mathieu Desnoyers + +[Retrieved from: +https://github.com/urcu/userspace-rcu/commit/e915ab84fd0c02d37504f3eb1e1f3be93ea6dc37] +Signed-off-by: Fabrice Fontaine +--- + include/urcu/tls-compat.h | 7 ++++++- + 1 file changed, 6 insertions(+), 1 deletion(-) + +diff --git a/include/urcu/tls-compat.h b/include/urcu/tls-compat.h +index 24ef1b9a..25cf375a 100644 +--- a/include/urcu/tls-compat.h ++++ b/include/urcu/tls-compat.h +@@ -34,7 +34,12 @@ extern "C" { + + #ifdef CONFIG_RCU_TLS + +-#if defined (__cplusplus) && (__cplusplus >= 201103L) ++/* ++ * Don't use C++ 'thread_local' on MacOs, the implementation is incompatible ++ * with C and will result in a link error when accessing an extern variable ++ * provided by the C library from C++ code. ++ */ ++#if defined (__cplusplus) && (__cplusplus >= 201103L) && !defined(__APPLE__) + # define URCU_TLS_STORAGE_CLASS thread_local + #elif defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) + # define URCU_TLS_STORAGE_CLASS _Thread_local diff --git a/package/liburcu/0003-Always-use-__thread-for-Thread-local-storage-except-on-MSVC.patch b/package/liburcu/0003-Always-use-__thread-for-Thread-local-storage-except-on-MSVC.patch new file mode 100644 index 0000000000..aa71cf2f20 --- /dev/null +++ b/package/liburcu/0003-Always-use-__thread-for-Thread-local-storage-except-on-MSVC.patch @@ -0,0 +1,53 @@ +From 2e359284497c361e3208501fc70d49b2c54dc4ef Mon Sep 17 00:00:00 2001 +From: Michael Jeanson +Date: Tue, 14 Sep 2021 10:41:08 -0400 +Subject: [PATCH] Always use '__thread' for Thread local storage except on MSVC + +Use the GCC extension '__thread' [1] for Thread local storage on all C +and C++ compilers except MSVC. + +While C11 and C++11 respectively offer '_Thread_local' and +'thread_local' as potentialy faster implementations, they offer no +guarantees of compatibility when used in a library interface which might +be used by both C and C++ client code. + +[1] https://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html + +Change-Id: If4fe8bcdbda24b21dedf382112bd5c5f836c00c8 +Signed-off-by: Michael Jeanson +Signed-off-by: Mathieu Desnoyers + +[Retrieved from: +https://github.com/urcu/userspace-rcu/commit/2e359284497c361e3208501fc70d49b2c54dc4ef] +Signed-off-by: Fabrice Fontaine +--- + include/urcu/tls-compat.h | 15 +++++++-------- + 1 file changed, 7 insertions(+), 8 deletions(-) + +diff --git a/include/urcu/tls-compat.h b/include/urcu/tls-compat.h +index 25cf375a..a2c94ded 100644 +--- a/include/urcu/tls-compat.h ++++ b/include/urcu/tls-compat.h +@@ -35,15 +35,14 @@ extern "C" { + #ifdef CONFIG_RCU_TLS + + /* +- * Don't use C++ 'thread_local' on MacOs, the implementation is incompatible +- * with C and will result in a link error when accessing an extern variable +- * provided by the C library from C++ code. ++ * Default to '__thread' on all C and C++ compilers except MSVC. While C11 has ++ * '_Thread_local' and C++11 has 'thread_local', only '__thread' seems to have ++ * a compatible implementation when linking public extern symbols across ++ * language boundaries. ++ * ++ * For more details, see 'https://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html'. + */ +-#if defined (__cplusplus) && (__cplusplus >= 201103L) && !defined(__APPLE__) +-# define URCU_TLS_STORAGE_CLASS thread_local +-#elif defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) +-# define URCU_TLS_STORAGE_CLASS _Thread_local +-#elif defined (_MSC_VER) ++#if defined(_MSC_VER) + # define URCU_TLS_STORAGE_CLASS __declspec(thread) + #else + # define URCU_TLS_STORAGE_CLASS __thread