tools headers: Adopt verbatim copy of compiletime_assert() from kernel sources

Will be needed when syncing the linux/bits.h header, in the next cset.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h
index 1827c2f..180f771 100644 (file)
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -10,6 +10,32 @@
 # define __compiletime_error(message)
 #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_, __COUNTER__)
+
 /* Optimization barrier */
 /* The "volatile" is due to gcc bugs */
 #define barrier() __asm__ __volatile__("": : :"memory")