include: types: Use __builtin_offsetof when supported

Clang provides a __builtin_offsetof which can be detected using
__has_builtin().

Signed-off-by: Alex Richardson <Alexander.Richardson@cl.cam.ac.uk>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
This commit is contained in:
Alex Richardson
2021-07-12 13:39:59 +01:00
committed by Anup Patel
parent 7210e90785
commit f3a8f603a7

View File

@@ -68,8 +68,14 @@ typedef unsigned long physical_size_t;
#define likely(x) __builtin_expect((x), 1)
#define unlikely(x) __builtin_expect((x), 0)
#ifndef __has_builtin
#define __has_builtin(...) 0
#endif
#undef offsetof
#ifdef __compiler_offsetof
#if __has_builtin(__builtin_offsetof)
#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE,MEMBER)
#elif defined(__compiler_offsetof)
#define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE,MEMBER)
#else
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)