svn commit: r233108 - stable/9/sys/sys

[Ed Schouten]

Author: ed
Date: Sun Mar 18 09:19:40 2012
New Revision: 233108
URL: http://svn.freebsd.org/changeset/base/233108

Log:
  MFC r228322,228330,228477,228495,228562,228564,228859,228897,229574,230277:
  
    Bring <sys/cdefs.h> in sync with FreeBSD HEAD:
  
    - Add an __alignof() for non-GCC and GCC < 2.95.
    - Attempt to implement the following C11 keywords: _Alignas(),
      _Alignof(), _Noreturn, _Static_assert() and _Thread_local.
    - Add __generic(), which allows us to do _Generic() in a portable
      fashion.
    - Improve __offsetof(), __DECONST(), __DEVOLATILE() and __DEQUALIFY()
      to use __uintptr_t and __size_t to make them work with less
      header prerequisites.
    - Add __has_feature(), __has_include() and __has_builtin() to make it
      easier to test against Clang features.
  
  Tested by:	linimon@'s exp-run (thanks!)

Modified:
  stable/9/sys/sys/cdefs.h
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/sys/cdefs.h
==============================================================================
--- stable/9/sys/sys/cdefs.h	Sun Mar 18 08:08:06 2012	(r233107)
+++ stable/9/sys/sys/cdefs.h	Sun Mar 18 09:19:40 2012	(r233108)
@@ -218,6 +218,54 @@
 #endif
 #endif
 
+#if !__GNUC_PREREQ__(2, 95)
+#define	__alignof(x)	__offsetof(struct { char __a; x __b; }, __b)
+#endif
+
+/*
+ * Keywords added in C11.
+ */
+#if defined(__cplusplus) && __cplusplus >= 201103L
+#define	_Alignas(e)		alignas(e)
+#define	_Alignof(e)		alignof(e)
+#define	_Noreturn		[[noreturn]]
+#define	_Static_assert(e, s)	static_assert(e, s)
+#define	_Thread_local		thread_local
+#elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
+/* Do nothing.  They are language keywords. */
+#else
+/* Not supported.  Implement them using our versions. */
+#define	_Alignas(x)		__aligned(x)
+#define	_Alignof(x)		__alignof(x)
+#define	_Noreturn		__dead2
+#define	_Thread_local		__thread
+#ifdef __COUNTER__
+#define	_Static_assert(x, y)	__Static_assert(x, __COUNTER__)
+#define	__Static_assert(x, y)	___Static_assert(x, y)
+#define	___Static_assert(x, y)	typedef char __assert_ ## y[(x) ? 1 : -1]
+#else
+#define	_Static_assert(x, y)	struct __hack
+#endif
+#endif
+
+/*
+ * Emulation of C11 _Generic().  Unlike the previously defined C11
+ * keywords, it is not possible to implement this using exactly the same
+ * syntax.  Therefore implement something similar under the name
+ * __generic().  Unlike _Generic(), this macro can only distinguish
+ * between a single type, so it requires nested invocations to
+ * distinguish multiple cases.
+ */
+
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
+#define	__generic(expr, t, yes, no)					\
+	_Generic(expr, t: yes, default: no)
+#elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus)
+#define	__generic(expr, t, yes, no)					\
+	__builtin_choose_expr(						\
+	    __builtin_types_compatible_p(__typeof(expr), t), yes, no)
+#endif
+
 #if __GNUC_PREREQ__(2, 96)
 #define	__malloc_like	__attribute__((__malloc__))
 #define	__pure		__attribute__((__pure__))
@@ -319,10 +367,11 @@
 #define __offsetof(type, field)	 __builtin_offsetof(type, field)
 #else
 #ifndef __cplusplus
-#define	__offsetof(type, field)	((size_t)(&((type *)0)->field))
+#define	__offsetof(type, field) \
+	((__size_t)(__uintptr_t)((const volatile void *)&((type *)0)->field))
 #else
 #define __offsetof(type, field)					\
-  (__offsetof__ (reinterpret_cast <size_t>			\
+  (__offsetof__ (reinterpret_cast <__size_t>			\
                  (&reinterpret_cast <const volatile char &>	\
                   (static_cast<type *> (0)->field))))
 #endif
@@ -450,15 +499,15 @@
 #endif
 
 #ifndef	__DECONST
-#define	__DECONST(type, var)	((type)(uintptr_t)(const void *)(var))
+#define	__DECONST(type, var)	((type)(__uintptr_t)(const void *)(var))
 #endif
 
 #ifndef	__DEVOLATILE
-#define	__DEVOLATILE(type, var)	((type)(uintptr_t)(volatile void *)(var))
+#define	__DEVOLATILE(type, var)	((type)(__uintptr_t)(volatile void *)(var))
 #endif
 
 #ifndef	__DEQUALIFY
-#define	__DEQUALIFY(type, var)	((type)(uintptr_t)(const volatile void *)(var))
+#define	__DEQUALIFY(type, var)	((type)(__uintptr_t)(const volatile void *)(var))
 #endif
 
 /*-
@@ -574,4 +623,14 @@
 #endif
 #endif
 
+#ifndef	__has_feature
+#define	__has_feature(x) 0
+#endif
+#ifndef	__has_include
+#define	__has_include(x) 0
+#endif
+#ifndef	__has_builtin
+#define	__has_builtin(x) 0
+#endif
+
 #endif /* !_SYS_CDEFS_H_ */