svn commit: r228495 - head/sys/sys

[Ed Schouten]

Hello Bruce,

After reading through your email, I think it's best to fix things using
the following patch. Essentially it does the following:

- It makes sure __alignof() is always present, by defining it as a macro
  for GCC < 2.95.
- All the C1X macros can now be implemented using the ones we already
  had (__dead2, etc). This means we don't need to repeat all the
  compiler version specific checks.
- While there, add struct __hack to the _Static_assert, as it always
  requires a semicolon.

Thanks for your feedback.

| Index: sys/sys/cdefs.h
| ===================================================================
| --- sys/sys/cdefs.h	(revision 228504)
| +++ sys/sys/cdefs.h	(working copy)
| @@ -230,27 +230,24 @@
|  #elif defined(__STDC_VERSION__) && __STDC_VERSION__ > 201000L
|  /* Do nothing.  They are language keywords. */
|  #else
| -/* Not supported.  Implement them manually. */
| -#ifdef __GNUC__
| -#define	_Alignas(e)		__attribute__((__aligned__(e)))
| -#define	_Alignof(e)		__alignof__(e)
| -#define	_Noreturn		__attribute__((__noreturn__))
| +/* Not supported.  Implement them using our versions. */
| +#define	_Alignas(e)		__aligned(e)
| +#define	_Alignof(e)		__alignof(e)
| +#define	_Noreturn		__dead2
|  #define	_Thread_local		__thread
| -#else
| -#define	_Alignas(e)
| -#define	_Alignof(e)		__offsetof(struct { char __a; e __b; }, __b)
| -#define	_Noreturn
| -#define	_Thread_local
| -#endif
|  #ifdef __COUNTER__
|  #define	_Static_assert(e, s)	__Static_assert(e, __COUNTER__)
|  #define	__Static_assert(e, c)	___Static_assert(e, c)
|  #define	___Static_assert(e, c)	typedef char __assert ## c[(e) ? 1 : -1]
|  #else
| -#define	_Static_assert(e, s)
| +#define	_Static_assert(e, s)	struct __hack
|  #endif
|  #endif
|  
| +#if !__GNUC_PREREQ__(2, 95)
| +#define	__alignof(x)	__offsetof(struct { char __a; e __b; }, __b)
| +#endif
| +
|  #if __GNUC_PREREQ__(2, 96)
|  #define	__malloc_like	__attribute__((__malloc__))
|  #define	__pure		__attribute__((__pure__))

-- 
 Ed Schouten <ed at 80386.nl>
 WWW: http://80386.nl/
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