Revert "compiler.h: Introduce caa_unqual_scalar_typeof"

[userspace-rcu.git] / include / urcu / compiler.h

diff --git a/include/urcu/compiler.h b/include/urcu/compiler.h
index 4806ee338a99706ae5bb9eedb503fdc54e00c661..376b5073facc82957f12ebad6a69cb2911b7c205 100644 (file)
--- a/include/urcu/compiler.h
+++ b/include/urcu/compiler.h
@@ -70,6 +70,23 @@
                (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))
 
@@ -108,7 +125,12 @@
 
 #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__)