[PATCH v3 07/13] xen/include: import sizeof_field() macro from Linux stddef.h

[Paul Durrant <paul@xxxxxxx>]

From: Paul Durrant <pdurrant@xxxxxxxxxx>

Co-locate it with the definition of offsetof() (since this is also in stddef.h
in the Linux kernel source). This macro will be needed in a subsequent patch.

Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <george.dunlap@xxxxxxxxxx>
Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
Cc: Julien Grall <julien@xxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
---
 xen/include/xen/compiler.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h
index c0e0ee9f27be..676c6ea1b0a0 100644
--- a/xen/include/xen/compiler.h
+++ b/xen/include/xen/compiler.h
@@ -76,6 +76,14 @@
 
 #define offsetof(a,b) __builtin_offsetof(a,b)
 
+/**
+ * sizeof_field(TYPE, MEMBER)
+ *
+ * @TYPE: The structure containing the field of interest
+ * @MEMBER: The field to return the size of
+ */
+#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+
 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
 #define alignof __alignof__
 #endif
-- 
2.20.1