[PATCH 4.9 16/29] tools include: Adopt __same_type() and __must_be_array() from the kernel

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

commit f6441aff8946f7fd6ab730d7eb9eba18a9ebeba4 upstream.

Will be used to adopt the more stringent version of ARRAY_SIZE(), the
one in the kernel sources.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-d85dpvay1hoqscpezlntyd8x@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 tools/include/linux/compiler-gcc.h |    3 +++
 tools/include/linux/compiler.h     |    5 +++++
 2 files changed, 8 insertions(+)

--- a/tools/include/linux/compiler-gcc.h
+++ b/tools/include/linux/compiler-gcc.h
@@ -16,3 +16,6 @@
 #if GCC_VERSION >= 40300
 # define __compiletime_error(message) __attribute__((error(message)))
 #endif /* GCC_VERSION >= 40300 */
+
+/* &a[0] degrades to a pointer: a different type from an array */
+#define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -17,6 +17,11 @@
 # define __always_inline	inline __attribute__((always_inline))
 #endif
 
+/* Are two types/vars the same type (ignoring qualifiers)? */
+#ifndef __same_type
+# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
+#endif
+
 #ifdef __ANDROID__
 /*
  * FIXME: Big hammer to get rid of tons of: