X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=urcu%2Ftls-compat.h;h=81b5f0c659b7a69b620fb3772566ecfb684703fc;hb=1182f6f0f7b86408594706001c841c56e2b8cbc8;hp=8ac1ea0615ddc2eb91ee51e9e15b89bd094d4c81;hpb=ff12c1236f766980d57b1b80e0bd571c21c3df7f;p=urcu.git

diff --git a/urcu/tls-compat.h b/urcu/tls-compat.h
index 8ac1ea0..81b5f0c 100644
--- a/urcu/tls-compat.h
+++ b/urcu/tls-compat.h
@@ -70,12 +70,20 @@ extern "C" {
 # define DEFINE_URCU_TLS(type, name)	\
 	CONFIG_RCU_TLS type name
 
+# define __DEFINE_URCU_TLS_GLOBAL(type, name)	\
+	CONFIG_RCU_TLS type name
+
 # define URCU_TLS(name)		(name)
 
 #else /* #ifndef CONFIG_RCU_TLS */
 
 /*
  * The *_1() macros ensure macro parameters are expanded.
+ *
+ * __DEFINE_URCU_TLS_GLOBAL and __URCU_TLS_CALL exist for the sole
+ * purpose of notifying applications compiled against non-fixed 0.7 and
+ * 0.8 userspace RCU headers and using multiple flavors concurrently to
+ * recompile against fixed userspace RCU headers.
  */
 
 # include <pthread.h>
@@ -87,7 +95,8 @@ struct urcu_tls {
 };
 
 # define DECLARE_URCU_TLS_1(type, name)				\
-	type *__tls_access_ ## name(void)
+	type *__tls_access2_ ## name(void)
+
 # define DECLARE_URCU_TLS(type, name)				\
 	DECLARE_URCU_TLS_1(type, name)
 
@@ -95,8 +104,14 @@ struct urcu_tls {
  * Note: we don't free memory at process exit, since it will be dealt
  * with by the OS.
  */
+# define __URCU_TLS_CALL_1(name)				\
+	__tls_access2_ ## name
+
+# define __URCU_TLS_CALL(name)					\
+	__URCU_TLS_CALL_1(name)
+
 # define DEFINE_URCU_TLS_1(type, name)				\
-	type *__tls_access_ ## name(void)			\
+	type *__tls_access2_ ## name(void)			\
 	{							\
 		static struct urcu_tls __tls_ ## name = {	\
 			.init_mutex = PTHREAD_MUTEX_INITIALIZER,\
@@ -124,10 +139,32 @@ struct urcu_tls {
 		return __tls_p;					\
 	}
 
+/*
+ * Define with an without macro expansion to handle erroneous callers.
+ * Trigger an abort() if the caller application uses the clashing symbol
+ * if a weak symbol is overridden.
+ */
+# define __DEFINE_URCU_TLS_GLOBAL(type, name)			\
+	DEFINE_URCU_TLS_1(type, name)				\
+	int __urcu_tls_symbol_refcount_ ## name __attribute__((weak)); \
+	static __attribute__((constructor))			\
+	void __urcu_tls_inc_refcount_ ## name(void)		\
+	{							\
+		__urcu_tls_symbol_refcount_ ## name++;		\
+	}							\
+	type *__tls_access_ ## name(void)			\
+	{							\
+		if (__urcu_tls_symbol_refcount_ ## name > 1) {	\
+			fprintf(stderr, "Error: Userspace RCU symbol clash for multiple concurrent flavors. Please upgrade liburcu libraries and headers, then recompile your application.\n"); \
+			abort();				\
+		} 						\
+		return __URCU_TLS_CALL(name)();			\
+	}
+
 # define DEFINE_URCU_TLS(type, name)				\
 	DEFINE_URCU_TLS_1(type, name)
 
-# define URCU_TLS_1(name)	(*__tls_access_ ## name())
+# define URCU_TLS_1(name)	(*__tls_access2_ ## name())
 
 # define URCU_TLS(name)		URCU_TLS_1(name)