kumquat-buildroot/package/liburcu/0003-Always-use-__thread-for-Thread-local-storage-except-on-MSVC.patch
Fabrice Fontaine 828daae908 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 9cedbcf494 and
109267f653:

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 <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
2021-11-09 23:02:56 +01:00

54 lines
2.2 KiB
Diff

From 2e359284497c361e3208501fc70d49b2c54dc4ef Mon Sep 17 00:00:00 2001
From: Michael Jeanson <mjeanson@efficios.com>
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 <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
[Retrieved from:
https://github.com/urcu/userspace-rcu/commit/2e359284497c361e3208501fc70d49b2c54dc4ef]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
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