X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=include%2Furcu%2Fcompiler.h;h=5b994076f47c913b28d636ae6e7262261befe103;hb=d3d3857f678627e7bbfb5a8d6f3bc15cd2a694d9;hp=4806ee338a99706ae5bb9eedb503fdc54e00c661;hpb=3f0dd283a89ab114ffbf5c3dd46463217c6bb2ff;p=urcu.git

diff --git a/include/urcu/compiler.h b/include/urcu/compiler.h
index 4806ee3..5b99407 100644
--- a/include/urcu/compiler.h
+++ b/include/urcu/compiler.h
@@ -1,26 +1,20 @@
+// SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
 #ifndef _URCU_COMPILER_H
 #define _URCU_COMPILER_H
 
 /*
- * compiler.h
- *
  * Compiler definitions.
- *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
  */
 
 #include <stddef.h>	/* for offsetof */
 
+#if defined __cplusplus
+# include <type_traits>	/* for std::remove_cv */
+#endif
+
 #define caa_likely(x)	__builtin_expect(!!(x), 1)
 #define caa_unlikely(x)	__builtin_expect(!!(x), 0)
 
@@ -70,6 +64,23 @@
 		(type *)((char *)__ptr - offsetof(type, member));	\
 	})
 
+/*
+ * caa_container_of_check_null - Get the address of an object containing a field.
+ *
+ * @ptr: pointer to the field.
+ * @type: type of the object.
+ * @member: name of the field within the object.
+ *
+ * Return the address of the object containing the field. Return NULL if
+ * @ptr is NULL.
+ */
+#define caa_container_of_check_null(ptr, type, member)			\
+	__extension__							\
+	({								\
+		const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \
+		(__ptr) ? (type *)((char *)__ptr - offsetof(type, member)) : NULL; \
+	})
+
 #define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
 #define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond))
 
@@ -82,7 +93,7 @@
 #define __rcu
 
 #ifdef __cplusplus
-#define URCU_FORCE_CAST(type, arg)	(reinterpret_cast<type>(arg))
+#define URCU_FORCE_CAST(_type, arg)	(reinterpret_cast<std::remove_cv<_type>::type>(arg))
 #else
 #define URCU_FORCE_CAST(type, arg)	((type) (arg))
 #endif
@@ -108,7 +119,12 @@
 
 #define CAA_ARRAY_SIZE(x)	(sizeof(x) / sizeof((x)[0]))
 
-#ifdef __GNUC__
+/*
+ * URCU_GCC_VERSION is used to blacklist specific GCC versions with known
+ * bugs, clang also defines these macros to an equivalent GCC version it
+ * claims to support, so exclude it.
+ */
+#if defined(__GNUC__) && !defined(__clang__)
 # define URCU_GCC_VERSION	(__GNUC__ * 10000 \
 				+ __GNUC_MINOR__ * 100 \
 				+ __GNUC_PATCHLEVEL__)