xemu/include/qemu/compiler.h
Michael S. Tsirkin d757573e69 compiler: expression version of QEMU_BUILD_BUG_ON
QEMU_BUILD_BUG_ON uses a typedef in order to be safe
to use outside functions, but sometimes it's useful
to have a version that can be used within an expression.
Following what Linux does, introduce QEMU_BUILD_BUG_ON_ZERO
that return zero after checking condition at build time.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
2017-02-01 03:37:17 +02:00

121 lines
3.5 KiB
C

/* compiler.h: macros to abstract away compiler specifics
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef COMPILER_H
#define COMPILER_H
#if defined __clang_analyzer__ || defined __COVERITY__
#define QEMU_STATIC_ANALYSIS 1
#endif
/*----------------------------------------------------------------------------
| The macro QEMU_GNUC_PREREQ tests for minimum version of the GNU C compiler.
| The code is a copy of SOFTFLOAT_GNUC_PREREQ, see softfloat-macros.h.
*----------------------------------------------------------------------------*/
#if defined(__GNUC__) && defined(__GNUC_MINOR__)
# define QEMU_GNUC_PREREQ(maj, min) \
((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
#else
# define QEMU_GNUC_PREREQ(maj, min) 0
#endif
#define QEMU_NORETURN __attribute__ ((__noreturn__))
#if QEMU_GNUC_PREREQ(3, 4)
#define QEMU_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
#else
#define QEMU_WARN_UNUSED_RESULT
#endif
#if QEMU_GNUC_PREREQ(4, 0)
#define QEMU_SENTINEL __attribute__((sentinel))
#else
#define QEMU_SENTINEL
#endif
#if QEMU_GNUC_PREREQ(4, 3)
#define QEMU_ARTIFICIAL __attribute__((always_inline, artificial))
#else
#define QEMU_ARTIFICIAL
#endif
#if defined(_WIN32)
# define QEMU_PACKED __attribute__((gcc_struct, packed))
#else
# define QEMU_PACKED __attribute__((packed))
#endif
#define QEMU_ALIGNED(X) __attribute__((aligned(X)))
#ifndef glue
#define xglue(x, y) x ## y
#define glue(x, y) xglue(x, y)
#define stringify(s) tostring(s)
#define tostring(s) #s
#endif
#ifndef likely
#if __GNUC__ < 3
#define __builtin_expect(x, n) (x)
#endif
#define likely(x) __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)
#endif
#ifndef container_of
#define container_of(ptr, type, member) ({ \
const typeof(((type *) 0)->member) *__mptr = (ptr); \
(type *) ((char *) __mptr - offsetof(type, member));})
#endif
/* Convert from a base type to a parent type, with compile time checking. */
#ifdef __GNUC__
#define DO_UPCAST(type, field, dev) ( __extension__ ( { \
char __attribute__((unused)) offset_must_be_zero[ \
-offsetof(type, field)]; \
container_of(dev, type, field);}))
#else
#define DO_UPCAST(type, field, dev) container_of(dev, type, field)
#endif
#define typeof_field(type, field) typeof(((type *)0)->field)
#define type_check(t1,t2) ((t1*)0 - (t2*)0)
#define QEMU_BUILD_BUG_ON_STRUCT(x) \
struct { \
int:(x) ? -1 : 1; \
}
#ifdef __COUNTER__
#define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \
glue(qemu_build_bug_on__, __COUNTER__) __attribute__((unused))
#else
#define QEMU_BUILD_BUG_ON(x)
#endif
#define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \
sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)))
#if defined __GNUC__
# if !QEMU_GNUC_PREREQ(4, 4)
/* gcc versions before 4.4.x don't support gnu_printf, so use printf. */
# define GCC_FMT_ATTR(n, m) __attribute__((format(printf, n, m)))
# else
/* Use gnu_printf when supported (qemu uses standard format strings). */
# define GCC_FMT_ATTR(n, m) __attribute__((format(gnu_printf, n, m)))
# if defined(_WIN32)
/* Map __printf__ to __gnu_printf__ because we want standard format strings
* even when MinGW or GLib include files use __printf__. */
# define __printf__ __gnu_printf__
# endif
# endif
#else
#define GCC_FMT_ATTR(n, m)
#endif
#endif /* COMPILER_H */