|
@@ -0,0 +1,55 @@
|
|
|
+#ifndef _LINUX_BUG_H
|
|
|
+#define _LINUX_BUG_H
|
|
|
+
|
|
|
+#include <linux/compiler.h>
|
|
|
+
|
|
|
+#ifdef __CHECKER__
|
|
|
+#define BUILD_BUG_ON_NOT_POWER_OF_2(n) (0)
|
|
|
+#define BUILD_BUG_ON_ZERO(e) (0)
|
|
|
+#define BUILD_BUG_ON_NULL(e) ((void*)0)
|
|
|
+#define BUILD_BUG_ON_INVALID(e) (0)
|
|
|
+#define BUILD_BUG_ON(condition) (0)
|
|
|
+#define BUILD_BUG() (0)
|
|
|
+#else /* __CHECKER__ */
|
|
|
+
|
|
|
+/* Force a compilation error if a constant expression is not a power of 2 */
|
|
|
+#define BUILD_BUG_ON_NOT_POWER_OF_2(n) \
|
|
|
+ BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
|
|
|
+
|
|
|
+/* Force a compilation error if condition is true, but also produce a
|
|
|
+ result (of value 0 and type size_t), so the expression can be used
|
|
|
+ e.g. in a structure initializer (or where-ever else comma expressions
|
|
|
+ aren't permitted). */
|
|
|
+#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
|
|
|
+#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
|
|
|
+
|
|
|
+/*
|
|
|
+ * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
|
|
|
+ * expression but avoids the generation of any code, even if that expression
|
|
|
+ * has side-effects.
|
|
|
+ */
|
|
|
+#define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
|
|
|
+
|
|
|
+/**
|
|
|
+ * BUILD_BUG_ON - break compile if a condition is true.
|
|
|
+ * @condition: the condition which the compiler should know is false.
|
|
|
+ *
|
|
|
+ * If you have some code which relies on certain constants being equal, or
|
|
|
+ * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
|
|
|
+ * detect if someone changes it.
|
|
|
+ *
|
|
|
+ * The implementation uses gcc's reluctance to create a negative array, but gcc
|
|
|
+ * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to
|
|
|
+ * inline functions). Luckily, in 4.3 they added the "error" function
|
|
|
+ * attribute just for this type of case. Thus, we use a negative sized array
|
|
|
+ * (should always create an error on gcc versions older than 4.4) and then call
|
|
|
+ * an undefined function with the error attribute (should always create an
|
|
|
+ * error on gcc 4.3 and later). If for some reason, neither creates a
|
|
|
+ * compile-time error, we'll still have a link-time error, which is harder to
|
|
|
+ * track down.
|
|
|
+ */
|
|
|
+#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
|
|
|
+
|
|
|
+#endif /* __CHECKER__ */
|
|
|
+
|
|
|
+#endif /* _LINUX_BUG_H */
|