[bpf-next v2 06/10] tools headers: Adopt compiletime_assert from kernel sources

Krzesimir Nowak
2019-06-25T19:43:34Z

This will come in handy to verify that the hardcoded size of the
context data in bpf_test struct is high enough to hold some struct.

Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>
---
tools/include/linux/compiler.h | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h
index 1827c2f973f9..b4e97751000a 100644
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -172,4 +172,32 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
# define __fallthrough
#endif

+
+#ifdef __OPTIMIZE__
+# define __compiletime_assert(condition, msg, prefix, suffix) \
+ do { \
+ extern void prefix ## suffix(void) __compiletime_error(msg); \
+ if (!(condition)) \
+ prefix ## suffix(); \
+ } while (0)
+#else
+# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)
+#endif
+
+#define _compiletime_assert(condition, msg, prefix, suffix) \
+ __compiletime_assert(condition, msg, prefix, suffix)
+
+/**
+ * compiletime_assert - break build and emit msg if condition is false
+ * @condition: a compile-time constant condition to check
+ * @msg: a message to emit if condition is false
+ *
+ * In tradition of POSIX assert, this macro will break the build if the
+ * supplied condition is *false*, emitting the supplied error message if the
+ * compiler has support to do so.
+ */
+#define compiletime_assert(condition, msg) \
+ _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
+
+
#endif /* _TOOLS_LINUX_COMPILER_H */
--
2.20.1