xref: /freebsd/sys/sys/cdefs.h (revision 535af610)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Berkeley Software Design, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)cdefs.h	8.8 (Berkeley) 1/9/95
35  * $FreeBSD$
36  */
37 
38 #ifndef	_SYS_CDEFS_H_
39 #define	_SYS_CDEFS_H_
40 
41 #if defined(_KERNEL) && defined(_STANDALONE)
42 #error "_KERNEL and _STANDALONE are mutually exclusive"
43 #endif
44 
45 /*
46  * Testing against Clang-specific extensions.
47  */
48 #ifndef	__has_attribute
49 #define	__has_attribute(x)	0
50 #endif
51 #ifndef	__has_extension
52 #define	__has_extension		__has_feature
53 #endif
54 #ifndef	__has_feature
55 #define	__has_feature(x)	0
56 #endif
57 #ifndef	__has_include
58 #define	__has_include(x)	0
59 #endif
60 #ifndef	__has_builtin
61 #define	__has_builtin(x)	0
62 #endif
63 
64 #if defined(__cplusplus)
65 #define	__BEGIN_DECLS	extern "C" {
66 #define	__END_DECLS	}
67 #else
68 #define	__BEGIN_DECLS
69 #define	__END_DECLS
70 #endif
71 
72 /*
73  * This code has been put in place to help reduce the addition of
74  * compiler specific defines in FreeBSD code.  It helps to aid in
75  * having a compiler-agnostic source tree.
76  */
77 
78 #if defined(__GNUC__)
79 
80 #if __GNUC__ >= 3
81 #define	__GNUCLIKE_ASM 3
82 #define	__GNUCLIKE_MATH_BUILTIN_CONSTANTS
83 #else
84 #define	__GNUCLIKE_ASM 2
85 #endif
86 #define	__GNUCLIKE___TYPEOF 1
87 #define	__GNUCLIKE___SECTION 1
88 
89 #define	__GNUCLIKE_CTOR_SECTION_HANDLING 1
90 
91 #define	__GNUCLIKE_BUILTIN_CONSTANT_P 1
92 
93 #if (__GNUC_MINOR__ > 95 || __GNUC__ >= 3)
94 #define	__GNUCLIKE_BUILTIN_VARARGS 1
95 #define	__GNUCLIKE_BUILTIN_STDARG 1
96 #define	__GNUCLIKE_BUILTIN_VAALIST 1
97 #endif
98 
99 #define	__GNUC_VA_LIST_COMPATIBILITY 1
100 
101 /*
102  * Compiler memory barriers, specific to gcc and clang.
103  */
104 #define	__compiler_membar()	__asm __volatile(" " : : : "memory")
105 
106 #define	__GNUCLIKE_BUILTIN_NEXT_ARG 1
107 #define	__GNUCLIKE_MATH_BUILTIN_RELOPS
108 
109 #define	__GNUCLIKE_BUILTIN_MEMCPY 1
110 
111 /* XXX: if __GNUC__ >= 2: not tested everywhere originally, where replaced */
112 #define	__CC_SUPPORTS_INLINE 1
113 #define	__CC_SUPPORTS___INLINE 1
114 #define	__CC_SUPPORTS___INLINE__ 1
115 
116 #define	__CC_SUPPORTS___FUNC__ 1
117 #define	__CC_SUPPORTS_WARNING 1
118 
119 #define	__CC_SUPPORTS_VARADIC_XXX 1 /* see varargs.h */
120 
121 #define	__CC_SUPPORTS_DYNAMIC_ARRAY_INIT 1
122 
123 #endif /* __GNUC__ */
124 
125 /*
126  * Macro to test if we're using a specific version of gcc or later.
127  */
128 #if defined(__GNUC__)
129 #define	__GNUC_PREREQ__(ma, mi)	\
130 	(__GNUC__ > (ma) || __GNUC__ == (ma) && __GNUC_MINOR__ >= (mi))
131 #else
132 #define	__GNUC_PREREQ__(ma, mi)	0
133 #endif
134 
135 /*
136  * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
137  * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
138  * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI
139  * mode -- there must be no spaces between its arguments, and for nested
140  * __CONCAT's, all the __CONCAT's must be at the left.  __CONCAT can also
141  * concatenate double-quoted strings produced by the __STRING macro, but
142  * this only works with ANSI C.
143  *
144  * __XSTRING is like __STRING, but it expands any macros in its argument
145  * first.  It is only available with ANSI C.
146  */
147 #if defined(__STDC__) || defined(__cplusplus)
148 #define	__P(protos)	protos		/* full-blown ANSI C */
149 #define	__CONCAT1(x,y)	x ## y
150 #define	__CONCAT(x,y)	__CONCAT1(x,y)
151 #define	__STRING(x)	#x		/* stringify without expanding x */
152 #define	__XSTRING(x)	__STRING(x)	/* expand x, then stringify */
153 
154 #define	__const		const		/* define reserved names to standard */
155 #define	__signed	signed
156 #define	__volatile	volatile
157 #if defined(__cplusplus)
158 #define	__inline	inline		/* convert to C++ keyword */
159 #else
160 #if !(defined(__CC_SUPPORTS___INLINE))
161 #define	__inline			/* delete GCC keyword */
162 #endif /* ! __CC_SUPPORTS___INLINE */
163 #endif /* !__cplusplus */
164 
165 #else	/* !(__STDC__ || __cplusplus) */
166 #define	__P(protos)	()		/* traditional C preprocessor */
167 #define	__CONCAT(x,y)	x/**/y
168 #define	__STRING(x)	"x"
169 
170 #if !defined(__CC_SUPPORTS___INLINE)
171 #define	__const				/* delete pseudo-ANSI C keywords */
172 #define	__inline
173 #define	__signed
174 #define	__volatile
175 /*
176  * In non-ANSI C environments, new programs will want ANSI-only C keywords
177  * deleted from the program and old programs will want them left alone.
178  * When using a compiler other than gcc, programs using the ANSI C keywords
179  * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS.
180  * When using "gcc -traditional", we assume that this is the intent; if
181  * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone.
182  */
183 #ifndef	NO_ANSI_KEYWORDS
184 #define	const				/* delete ANSI C keywords */
185 #define	inline
186 #define	signed
187 #define	volatile
188 #endif	/* !NO_ANSI_KEYWORDS */
189 #endif	/* !__CC_SUPPORTS___INLINE */
190 #endif	/* !(__STDC__ || __cplusplus) */
191 
192 /*
193  * Compiler-dependent macros to help declare dead (non-returning) and
194  * pure (no side effects) functions, and unused variables.  They are
195  * null except for versions of gcc that are known to support the features
196  * properly (old versions of gcc-2 supported the dead and pure features
197  * in a different (wrong) way).  If we do not provide an implementation
198  * for a given compiler, let the compile fail if it is told to use
199  * a feature that we cannot live without.
200  */
201 #define	__weak_symbol	__attribute__((__weak__))
202 #if !__GNUC_PREREQ__(2, 5)
203 #define	__dead2
204 #define	__pure2
205 #define	__unused
206 #endif
207 #if __GNUC__ == 2 && __GNUC_MINOR__ >= 5 && __GNUC_MINOR__ < 7
208 #define	__dead2		__attribute__((__noreturn__))
209 #define	__pure2		__attribute__((__const__))
210 #define	__unused
211 /* XXX Find out what to do for __packed, __aligned and __section */
212 #endif
213 #if __GNUC_PREREQ__(2, 7)
214 #define	__dead2		__attribute__((__noreturn__))
215 #define	__pure2		__attribute__((__const__))
216 #define	__unused	__attribute__((__unused__))
217 #define	__used		__attribute__((__used__))
218 #define	__packed	__attribute__((__packed__))
219 #define	__aligned(x)	__attribute__((__aligned__(x)))
220 #define	__section(x)	__attribute__((__section__(x)))
221 #endif
222 #if __GNUC_PREREQ__(4, 3) || __has_attribute(__alloc_size__)
223 #define	__alloc_size(x)	__attribute__((__alloc_size__(x)))
224 #define	__alloc_size2(n, x)	__attribute__((__alloc_size__(n, x)))
225 #else
226 #define	__alloc_size(x)
227 #define	__alloc_size2(n, x)
228 #endif
229 #if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__)
230 #define	__alloc_align(x)	__attribute__((__alloc_align__(x)))
231 #else
232 #define	__alloc_align(x)
233 #endif
234 
235 #if !__GNUC_PREREQ__(2, 95)
236 #define	__alignof(x)	__offsetof(struct { char __a; x __b; }, __b)
237 #endif
238 
239 /*
240  * Keywords added in C11.
241  */
242 
243 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
244 
245 #if !__has_extension(c_alignas)
246 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
247     __has_extension(cxx_alignas)
248 #define	_Alignas(x)		alignas(x)
249 #else
250 /* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */
251 #define	_Alignas(x)		__aligned(x)
252 #endif
253 #endif
254 
255 #if defined(__cplusplus) && __cplusplus >= 201103L
256 #define	_Alignof(x)		alignof(x)
257 #else
258 #define	_Alignof(x)		__alignof(x)
259 #endif
260 
261 #if !defined(__cplusplus) && !__has_extension(c_atomic) && \
262 	!__has_extension(cxx_atomic) && !__GNUC_PREREQ__(4, 7)
263 /*
264  * No native support for _Atomic(). Place object in structure to prevent
265  * most forms of direct non-atomic access.
266  */
267 #define	_Atomic(T)		struct { T volatile __val; }
268 #endif
269 
270 #if defined(__cplusplus) && __cplusplus >= 201103L
271 #define	_Noreturn		[[noreturn]]
272 #else
273 #define	_Noreturn		__dead2
274 #endif
275 
276 #if !__has_extension(c_static_assert)
277 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
278     __has_extension(cxx_static_assert)
279 #define	_Static_assert(x, y)	static_assert(x, y)
280 #elif __GNUC_PREREQ__(4,6) && !defined(__cplusplus)
281 /* Nothing, gcc 4.6 and higher has _Static_assert built-in */
282 #elif defined(__COUNTER__)
283 #define	_Static_assert(x, y)	__Static_assert(x, __COUNTER__)
284 #define	__Static_assert(x, y)	___Static_assert(x, y)
285 #define	___Static_assert(x, y)	typedef char __assert_ ## y[(x) ? 1 : -1] \
286 				__unused
287 #else
288 #define	_Static_assert(x, y)	struct __hack
289 #endif
290 #endif
291 
292 #if !__has_extension(c_thread_local)
293 /*
294  * XXX: Some compilers (Clang 3.3, GCC 4.7) falsely announce C++11 mode
295  * without actually supporting the thread_local keyword. Don't check for
296  * the presence of C++11 when defining _Thread_local.
297  */
298 #if /* (defined(__cplusplus) && __cplusplus >= 201103L) || */ \
299     __has_extension(cxx_thread_local)
300 #define	_Thread_local		thread_local
301 #else
302 #define	_Thread_local		__thread
303 #endif
304 #endif
305 
306 #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */
307 
308 /*
309  * Emulation of C11 _Generic().  Unlike the previously defined C11
310  * keywords, it is not possible to implement this using exactly the same
311  * syntax.  Therefore implement something similar under the name
312  * __generic().  Unlike _Generic(), this macro can only distinguish
313  * between a single type, so it requires nested invocations to
314  * distinguish multiple cases.
315  *
316  * Note that the comma operator is used to force expr to decay in
317  * order to match _Generic().
318  */
319 
320 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \
321     __has_extension(c_generic_selections)
322 #define	__generic(expr, t, yes, no)					\
323 	_Generic(expr, t: yes, default: no)
324 #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus)
325 #define	__generic(expr, t, yes, no)					\
326 	__builtin_choose_expr(						\
327 	    __builtin_types_compatible_p(__typeof((0, (expr))), t), yes, no)
328 #endif
329 
330 /*
331  * C99 Static array indices in function parameter declarations.  Syntax such as:
332  * void bar(int myArray[static 10]);
333  * is allowed in C99 but not in C++.  Define __min_size appropriately so
334  * headers using it can be compiled in either language.  Use like this:
335  * void bar(int myArray[__min_size(10)]);
336  */
337 #if !defined(__cplusplus) && \
338     (defined(__clang__) || __GNUC_PREREQ__(4, 6)) && \
339     (!defined(__STDC_VERSION__) || (__STDC_VERSION__ >= 199901))
340 #define __min_size(x)	static (x)
341 #else
342 #define __min_size(x)	(x)
343 #endif
344 
345 #if __GNUC_PREREQ__(2, 96)
346 #define	__malloc_like	__attribute__((__malloc__))
347 #define	__pure		__attribute__((__pure__))
348 #else
349 #define	__malloc_like
350 #define	__pure
351 #endif
352 
353 #if __GNUC_PREREQ__(3, 1)
354 #define	__always_inline	__attribute__((__always_inline__))
355 #else
356 #define	__always_inline
357 #endif
358 
359 #if __GNUC_PREREQ__(3, 1)
360 #define	__noinline	__attribute__ ((__noinline__))
361 #else
362 #define	__noinline
363 #endif
364 
365 #if __GNUC_PREREQ__(3, 4)
366 #define	__fastcall	__attribute__((__fastcall__))
367 #define	__result_use_check	__attribute__((__warn_unused_result__))
368 #else
369 #define	__fastcall
370 #define	__result_use_check
371 #endif
372 
373 #if __GNUC_PREREQ__(4, 1)
374 #define	__returns_twice	__attribute__((__returns_twice__))
375 #else
376 #define	__returns_twice
377 #endif
378 
379 #if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable)
380 #define	__unreachable()	__builtin_unreachable()
381 #else
382 #define	__unreachable()	((void)0)
383 #endif
384 
385 /* XXX: should use `#if __STDC_VERSION__ < 199901'. */
386 #if !__GNUC_PREREQ__(2, 7)
387 #define	__func__	NULL
388 #endif
389 
390 #if (defined(__GNUC__) && __GNUC__ >= 2) && !defined(__STRICT_ANSI__) || __STDC_VERSION__ >= 199901
391 #define	__LONG_LONG_SUPPORTED
392 #endif
393 
394 /* C++11 exposes a load of C99 stuff */
395 #if defined(__cplusplus) && __cplusplus >= 201103L
396 #define	__LONG_LONG_SUPPORTED
397 #ifndef	__STDC_LIMIT_MACROS
398 #define	__STDC_LIMIT_MACROS
399 #endif
400 #ifndef	__STDC_CONSTANT_MACROS
401 #define	__STDC_CONSTANT_MACROS
402 #endif
403 #endif
404 
405 /*
406  * We use `__restrict' as a way to define the `restrict' type qualifier
407  * without disturbing older software that is unaware of C99 keywords.
408  * GCC also provides `__restrict' as an extension to support C99-style
409  * restricted pointers in other language modes.
410  */
411 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901
412 #define	__restrict	restrict
413 #elif !__GNUC_PREREQ__(2, 95)
414 #define	__restrict
415 #endif
416 
417 /*
418  * GNU C version 2.96 adds explicit branch prediction so that
419  * the CPU back-end can hint the processor and also so that
420  * code blocks can be reordered such that the predicted path
421  * sees a more linear flow, thus improving cache behavior, etc.
422  *
423  * The following two macros provide us with a way to utilize this
424  * compiler feature.  Use __predict_true() if you expect the expression
425  * to evaluate to true, and __predict_false() if you expect the
426  * expression to evaluate to false.
427  *
428  * A few notes about usage:
429  *
430  *	* Generally, __predict_false() error condition checks (unless
431  *	  you have some _strong_ reason to do otherwise, in which case
432  *	  document it), and/or __predict_true() `no-error' condition
433  *	  checks, assuming you want to optimize for the no-error case.
434  *
435  *	* Other than that, if you don't know the likelihood of a test
436  *	  succeeding from empirical or other `hard' evidence, don't
437  *	  make predictions.
438  *
439  *	* These are meant to be used in places that are run `a lot'.
440  *	  It is wasteful to make predictions in code that is run
441  *	  seldomly (e.g. at subsystem initialization time) as the
442  *	  basic block reordering that this affects can often generate
443  *	  larger code.
444  */
445 #if __GNUC_PREREQ__(2, 96)
446 #define	__predict_true(exp)     __builtin_expect((exp), 1)
447 #define	__predict_false(exp)    __builtin_expect((exp), 0)
448 #else
449 #define	__predict_true(exp)     (exp)
450 #define	__predict_false(exp)    (exp)
451 #endif
452 
453 #if __GNUC_PREREQ__(4, 0)
454 #define	__null_sentinel	__attribute__((__sentinel__))
455 #define	__exported	__attribute__((__visibility__("default")))
456 #define	__hidden	__attribute__((__visibility__("hidden")))
457 #else
458 #define	__null_sentinel
459 #define	__exported
460 #define	__hidden
461 #endif
462 
463 /*
464  * We define this here since <stddef.h>, <sys/queue.h>, and <sys/types.h>
465  * require it.
466  */
467 #if __GNUC_PREREQ__(4, 1)
468 #define	__offsetof(type, field)	 __builtin_offsetof(type, field)
469 #else
470 #ifndef __cplusplus
471 #define	__offsetof(type, field) \
472 	((__size_t)(__uintptr_t)((const volatile void *)&((type *)0)->field))
473 #else
474 #define	__offsetof(type, field)					\
475   (__offsetof__ (reinterpret_cast <__size_t>			\
476                  (&reinterpret_cast <const volatile char &>	\
477                   (static_cast<type *> (0)->field))))
478 #endif
479 #endif
480 #define	__rangeof(type, start, end) \
481 	(__offsetof(type, end) - __offsetof(type, start))
482 
483 /*
484  * Given the pointer x to the member m of the struct s, return
485  * a pointer to the containing structure.  When using GCC, we first
486  * assign pointer x to a local variable, to check that its type is
487  * compatible with member m.
488  */
489 #if __GNUC_PREREQ__(3, 1)
490 #define	__containerof(x, s, m) ({					\
491 	const volatile __typeof(((s *)0)->m) *__x = (x);		\
492 	__DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m));\
493 })
494 #else
495 #define	__containerof(x, s, m)						\
496 	__DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m))
497 #endif
498 
499 /*
500  * Compiler-dependent macros to declare that functions take printf-like
501  * or scanf-like arguments.  They are null except for versions of gcc
502  * that are known to support the features properly (old versions of gcc-2
503  * didn't permit keeping the keywords out of the application namespace).
504  */
505 #if !__GNUC_PREREQ__(2, 7)
506 #define	__printflike(fmtarg, firstvararg)
507 #define	__scanflike(fmtarg, firstvararg)
508 #define	__format_arg(fmtarg)
509 #define	__strfmonlike(fmtarg, firstvararg)
510 #define	__strftimelike(fmtarg, firstvararg)
511 #else
512 #define	__printflike(fmtarg, firstvararg) \
513 	    __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
514 #define	__scanflike(fmtarg, firstvararg) \
515 	    __attribute__((__format__ (__scanf__, fmtarg, firstvararg)))
516 #define	__format_arg(fmtarg)	__attribute__((__format_arg__ (fmtarg)))
517 #define	__strfmonlike(fmtarg, firstvararg) \
518 	    __attribute__((__format__ (__strfmon__, fmtarg, firstvararg)))
519 #define	__strftimelike(fmtarg, firstvararg) \
520 	    __attribute__((__format__ (__strftime__, fmtarg, firstvararg)))
521 #endif
522 
523 /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */
524 #if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \
525     defined(__GNUC__)
526 #define	__printf0like(fmtarg, firstvararg) \
527 	    __attribute__((__format__ (__printf0__, fmtarg, firstvararg)))
528 #else
529 #define	__printf0like(fmtarg, firstvararg)
530 #endif
531 
532 #if defined(__GNUC__)
533 #define	__strong_reference(sym,aliassym)	\
534 	extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym)))
535 #ifdef __STDC__
536 #define	__weak_reference(sym,alias)	\
537 	__asm__(".weak " #alias);	\
538 	__asm__(".equ "  #alias ", " #sym)
539 #define	__warn_references(sym,msg)	\
540 	__asm__(".section .gnu.warning." #sym);	\
541 	__asm__(".asciz \"" msg "\"");	\
542 	__asm__(".previous")
543 #define	__sym_compat(sym,impl,verid)	\
544 	__asm__(".symver " #impl ", " #sym "@" #verid)
545 #define	__sym_default(sym,impl,verid)	\
546 	__asm__(".symver " #impl ", " #sym "@@@" #verid)
547 #else
548 #define	__weak_reference(sym,alias)	\
549 	__asm__(".weak alias");		\
550 	__asm__(".equ alias, sym")
551 #define	__warn_references(sym,msg)	\
552 	__asm__(".section .gnu.warning.sym"); \
553 	__asm__(".asciz \"msg\"");	\
554 	__asm__(".previous")
555 #define	__sym_compat(sym,impl,verid)	\
556 	__asm__(".symver impl, sym@verid")
557 #define	__sym_default(impl,sym,verid)	\
558 	__asm__(".symver impl, sym@@@verid")
559 #endif	/* __STDC__ */
560 #endif	/* __GNUC__ */
561 
562 #define	__GLOBL(sym)	__asm__(".globl " __XSTRING(sym))
563 #define	__WEAK(sym)	__asm__(".weak " __XSTRING(sym))
564 
565 #if defined(__GNUC__)
566 #define	__IDSTRING(name,string)	__asm__(".ident\t\"" string "\"")
567 #else
568 /*
569  * The following definition might not work well if used in header files,
570  * but it should be better than nothing.  If you want a "do nothing"
571  * version, then it should generate some harmless declaration, such as:
572  *    #define	__IDSTRING(name,string)	struct __hack
573  */
574 #define	__IDSTRING(name,string)	static const char name[] __unused = string
575 #endif
576 
577 /*
578  * Embed the rcs id of a source file in the resulting library.  Note that in
579  * more recent ELF binutils, we use .ident allowing the ID to be stripped.
580  * Usage:
581  *	__FBSDID("$FreeBSD$");
582  */
583 #ifndef	__FBSDID
584 #if !defined(STRIP_FBSDID)
585 #define	__FBSDID(s)	__IDSTRING(__CONCAT(__rcsid_,__LINE__),s)
586 #else
587 #define	__FBSDID(s)	struct __hack
588 #endif
589 #endif
590 
591 #ifndef	__RCSID
592 #ifndef	NO__RCSID
593 #define	__RCSID(s)	__IDSTRING(__CONCAT(__rcsid_,__LINE__),s)
594 #else
595 #define	__RCSID(s)	struct __hack
596 #endif
597 #endif
598 
599 #ifndef	__RCSID_SOURCE
600 #ifndef	NO__RCSID_SOURCE
601 #define	__RCSID_SOURCE(s)	__IDSTRING(__CONCAT(__rcsid_source_,__LINE__),s)
602 #else
603 #define	__RCSID_SOURCE(s)	struct __hack
604 #endif
605 #endif
606 
607 #ifndef	__SCCSID
608 #ifndef	NO__SCCSID
609 #define	__SCCSID(s)	__IDSTRING(__CONCAT(__sccsid_,__LINE__),s)
610 #else
611 #define	__SCCSID(s)	struct __hack
612 #endif
613 #endif
614 
615 #ifndef	__COPYRIGHT
616 #ifndef	NO__COPYRIGHT
617 #define	__COPYRIGHT(s)	__IDSTRING(__CONCAT(__copyright_,__LINE__),s)
618 #else
619 #define	__COPYRIGHT(s)	struct __hack
620 #endif
621 #endif
622 
623 #ifndef	__DECONST
624 #define	__DECONST(type, var)	((type)(__uintptr_t)(const void *)(var))
625 #endif
626 
627 #ifndef	__DEVOLATILE
628 #define	__DEVOLATILE(type, var)	((type)(__uintptr_t)(volatile void *)(var))
629 #endif
630 
631 #ifndef	__DEQUALIFY
632 #define	__DEQUALIFY(type, var)	((type)(__uintptr_t)(const volatile void *)(var))
633 #endif
634 
635 /*-
636  * The following definitions are an extension of the behavior originally
637  * implemented in <sys/_posix.h>, but with a different level of granularity.
638  * POSIX.1 requires that the macros we test be defined before any standard
639  * header file is included.
640  *
641  * Here's a quick run-down of the versions (and some informal names)
642  *  defined(_POSIX_SOURCE)		1003.1-1988
643  *					encoded as 198808 below
644  *  _POSIX_C_SOURCE == 1		1003.1-1990
645  *					encoded as 199009 below
646  *  _POSIX_C_SOURCE == 2		1003.2-1992 C Language Binding Option
647  *					encoded as 199209 below
648  *  _POSIX_C_SOURCE == 199309		1003.1b-1993
649  *					(1003.1 Issue 4, Single Unix Spec v1, Unix 93)
650  *  _POSIX_C_SOURCE == 199506		1003.1c-1995, 1003.1i-1995,
651  *					and the omnibus ISO/IEC 9945-1: 1996
652  *					(1003.1 Issue 5, Single	Unix Spec v2, Unix 95)
653  *  _POSIX_C_SOURCE == 200112		1003.1-2001 (1003.1 Issue 6, Unix 03)
654  *  _POSIX_C_SOURCE == 200809		1003.1-2008 (1003.1 Issue 7)
655  *					IEEE Std 1003.1-2017 (Rev of 1003.1-2008) is
656  *					1003.1-2008 with two TCs applied with
657  *					_POSIX_C_SOURCE=200809 and _XOPEN_SOURCE=700
658  *
659  * In addition, the X/Open Portability Guide, which is now the Single UNIX
660  * Specification, defines a feature-test macro which indicates the version of
661  * that specification, and which subsumes _POSIX_C_SOURCE.
662  *
663  * Our macros begin with two underscores to avoid namespace screwage.
664  */
665 
666 /* Deal with IEEE Std. 1003.1-1990, in which _POSIX_C_SOURCE == 1. */
667 #if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 1
668 #undef _POSIX_C_SOURCE		/* Probably illegal, but beyond caring now. */
669 #define	_POSIX_C_SOURCE		199009
670 #endif
671 
672 /* Deal with IEEE Std. 1003.2-1992, in which _POSIX_C_SOURCE == 2. */
673 #if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 2
674 #undef _POSIX_C_SOURCE
675 #define	_POSIX_C_SOURCE		199209
676 #endif
677 
678 /* Deal with various X/Open Portability Guides and Single UNIX Spec. */
679 #ifdef _XOPEN_SOURCE
680 #if _XOPEN_SOURCE - 0 >= 700
681 #define	__XSI_VISIBLE		700
682 #undef _POSIX_C_SOURCE
683 #define	_POSIX_C_SOURCE		200809
684 #elif _XOPEN_SOURCE - 0 >= 600
685 #define	__XSI_VISIBLE		600
686 #undef _POSIX_C_SOURCE
687 #define	_POSIX_C_SOURCE		200112
688 #elif _XOPEN_SOURCE - 0 >= 500
689 #define	__XSI_VISIBLE		500
690 #undef _POSIX_C_SOURCE
691 #define	_POSIX_C_SOURCE		199506
692 #endif
693 #endif
694 
695 /*
696  * Deal with all versions of POSIX.  The ordering relative to the tests above is
697  * important.
698  */
699 #if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE)
700 #define	_POSIX_C_SOURCE		198808
701 #endif
702 #ifdef _POSIX_C_SOURCE
703 #if _POSIX_C_SOURCE >= 200809
704 #define	__POSIX_VISIBLE		200809
705 #define	__ISO_C_VISIBLE		1999
706 #elif _POSIX_C_SOURCE >= 200112
707 #define	__POSIX_VISIBLE		200112
708 #define	__ISO_C_VISIBLE		1999
709 #elif _POSIX_C_SOURCE >= 199506
710 #define	__POSIX_VISIBLE		199506
711 #define	__ISO_C_VISIBLE		1990
712 #elif _POSIX_C_SOURCE >= 199309
713 #define	__POSIX_VISIBLE		199309
714 #define	__ISO_C_VISIBLE		1990
715 #elif _POSIX_C_SOURCE >= 199209
716 #define	__POSIX_VISIBLE		199209
717 #define	__ISO_C_VISIBLE		1990
718 #elif _POSIX_C_SOURCE >= 199009
719 #define	__POSIX_VISIBLE		199009
720 #define	__ISO_C_VISIBLE		1990
721 #else
722 #define	__POSIX_VISIBLE		198808
723 #define	__ISO_C_VISIBLE		0
724 #endif /* _POSIX_C_SOURCE */
725 /*
726  * Both glibc and OpenBSD enable c11 features when _ISOC11_SOURCE is defined, or
727  * when compiling with -stdc=c11. A strict reading of the standard would suggest
728  * doing it only for the former. However, a strict reading also requires C99
729  * mode only, so building with C11 is already undefined. Follow glibc's and
730  * OpenBSD's lead for this non-standard configuration for maximum compatibility.
731  */
732 #if _ISOC11_SOURCE || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L)
733 #undef __ISO_C_VISIBLE
734 #define __ISO_C_VISIBLE		2011
735 #endif
736 #else
737 /*-
738  * Deal with _ANSI_SOURCE:
739  * If it is defined, and no other compilation environment is explicitly
740  * requested, then define our internal feature-test macros to zero.  This
741  * makes no difference to the preprocessor (undefined symbols in preprocessing
742  * expressions are defined to have value zero), but makes it more convenient for
743  * a test program to print out the values.
744  *
745  * If a program mistakenly defines _ANSI_SOURCE and some other macro such as
746  * _POSIX_C_SOURCE, we will assume that it wants the broader compilation
747  * environment (and in fact we will never get here).
748  */
749 #if defined(_ANSI_SOURCE)	/* Hide almost everything. */
750 #define	__POSIX_VISIBLE		0
751 #define	__XSI_VISIBLE		0
752 #define	__BSD_VISIBLE		0
753 #define	__ISO_C_VISIBLE		1990
754 #define	__EXT1_VISIBLE		0
755 #elif defined(_C99_SOURCE)	/* Localism to specify strict C99 env. */
756 #define	__POSIX_VISIBLE		0
757 #define	__XSI_VISIBLE		0
758 #define	__BSD_VISIBLE		0
759 #define	__ISO_C_VISIBLE		1999
760 #define	__EXT1_VISIBLE		0
761 #elif defined(_C11_SOURCE)	/* Localism to specify strict C11 env. */
762 #define	__POSIX_VISIBLE		0
763 #define	__XSI_VISIBLE		0
764 #define	__BSD_VISIBLE		0
765 #define	__ISO_C_VISIBLE		2011
766 #define	__EXT1_VISIBLE		0
767 #else				/* Default environment: show everything. */
768 #define	__POSIX_VISIBLE		200809
769 #define	__XSI_VISIBLE		700
770 #define	__BSD_VISIBLE		1
771 #define	__ISO_C_VISIBLE		2011
772 #define	__EXT1_VISIBLE		1
773 #endif
774 #endif
775 
776 /* User override __EXT1_VISIBLE */
777 #if defined(__STDC_WANT_LIB_EXT1__)
778 #undef	__EXT1_VISIBLE
779 #if __STDC_WANT_LIB_EXT1__
780 #define	__EXT1_VISIBLE		1
781 #else
782 #define	__EXT1_VISIBLE		0
783 #endif
784 #endif /* __STDC_WANT_LIB_EXT1__ */
785 
786 /*
787  * Old versions of GCC use non-standard ARM arch symbols; acle-compat.h
788  * translates them to __ARM_ARCH and the modern feature symbols defined by ARM.
789  */
790 #if defined(__arm__) && !defined(__ARM_ARCH)
791 #include <machine/acle-compat.h>
792 #endif
793 
794 /*
795  * Nullability qualifiers: currently only supported by Clang.
796  */
797 #if !(defined(__clang__) && __has_feature(nullability))
798 #define	_Nonnull
799 #define	_Nullable
800 #define	_Null_unspecified
801 #define	__NULLABILITY_PRAGMA_PUSH
802 #define	__NULLABILITY_PRAGMA_POP
803 #else
804 #define	__NULLABILITY_PRAGMA_PUSH _Pragma("clang diagnostic push")	\
805 	_Pragma("clang diagnostic ignored \"-Wnullability-completeness\"")
806 #define	__NULLABILITY_PRAGMA_POP _Pragma("clang diagnostic pop")
807 #endif
808 
809 /*
810  * Type Safety Checking
811  *
812  * Clang provides additional attributes to enable checking type safety
813  * properties that cannot be enforced by the C type system.
814  */
815 
816 #if __has_attribute(__argument_with_type_tag__) && \
817     __has_attribute(__type_tag_for_datatype__)
818 #define	__arg_type_tag(arg_kind, arg_idx, type_tag_idx) \
819 	    __attribute__((__argument_with_type_tag__(arg_kind, arg_idx, type_tag_idx)))
820 #define	__datatype_type_tag(kind, type) \
821 	    __attribute__((__type_tag_for_datatype__(kind, type)))
822 #else
823 #define	__arg_type_tag(arg_kind, arg_idx, type_tag_idx)
824 #define	__datatype_type_tag(kind, type)
825 #endif
826 
827 /*
828  * Lock annotations.
829  *
830  * Clang provides support for doing basic thread-safety tests at
831  * compile-time, by marking which locks will/should be held when
832  * entering/leaving a functions.
833  *
834  * Furthermore, it is also possible to annotate variables and structure
835  * members to enforce that they are only accessed when certain locks are
836  * held.
837  */
838 
839 #if __has_extension(c_thread_safety_attributes)
840 #define	__lock_annotate(x)	__attribute__((x))
841 #else
842 #define	__lock_annotate(x)
843 #endif
844 
845 /* Structure implements a lock. */
846 #define	__lockable		__lock_annotate(lockable)
847 
848 /* Function acquires an exclusive or shared lock. */
849 #define	__locks_exclusive(...) \
850 	__lock_annotate(exclusive_lock_function(__VA_ARGS__))
851 #define	__locks_shared(...) \
852 	__lock_annotate(shared_lock_function(__VA_ARGS__))
853 
854 /* Function attempts to acquire an exclusive or shared lock. */
855 #define	__trylocks_exclusive(...) \
856 	__lock_annotate(exclusive_trylock_function(__VA_ARGS__))
857 #define	__trylocks_shared(...) \
858 	__lock_annotate(shared_trylock_function(__VA_ARGS__))
859 
860 /* Function releases a lock. */
861 #define	__unlocks(...)		__lock_annotate(unlock_function(__VA_ARGS__))
862 
863 /* Function asserts that an exclusive or shared lock is held. */
864 #define	__asserts_exclusive(...) \
865 	__lock_annotate(assert_exclusive_lock(__VA_ARGS__))
866 #define	__asserts_shared(...) \
867 	__lock_annotate(assert_shared_lock(__VA_ARGS__))
868 
869 /* Function requires that an exclusive or shared lock is or is not held. */
870 #define	__requires_exclusive(...) \
871 	__lock_annotate(exclusive_locks_required(__VA_ARGS__))
872 #define	__requires_shared(...) \
873 	__lock_annotate(shared_locks_required(__VA_ARGS__))
874 #define	__requires_unlocked(...) \
875 	__lock_annotate(locks_excluded(__VA_ARGS__))
876 
877 /* Function should not be analyzed. */
878 #define	__no_lock_analysis	__lock_annotate(no_thread_safety_analysis)
879 
880 /*
881  * Function or variable should not be sanitized, e.g., by AddressSanitizer.
882  * GCC has the nosanitize attribute, but as a function attribute only, and
883  * warns on use as a variable attribute.
884  */
885 #if __has_attribute(no_sanitize) && defined(__clang__)
886 #ifdef _KERNEL
887 #define __nosanitizeaddress	__attribute__((no_sanitize("kernel-address")))
888 #define __nosanitizememory	__attribute__((no_sanitize("kernel-memory")))
889 #else
890 #define __nosanitizeaddress	__attribute__((no_sanitize("address")))
891 #define __nosanitizememory	__attribute__((no_sanitize("memory")))
892 #endif
893 #define __nosanitizethread	__attribute__((no_sanitize("thread")))
894 #else
895 #define __nosanitizeaddress
896 #define __nosanitizememory
897 #define __nosanitizethread
898 #endif
899 
900 /*
901  * Make it possible to opt out of stack smashing protection.
902  */
903 #if __has_attribute(no_stack_protector)
904 #define	__nostackprotector	__attribute__((no_stack_protector))
905 #else
906 #define	__nostackprotector	\
907 	__attribute__((__optimize__("-fno-stack-protector")))
908 #endif
909 
910 /* Guard variables and structure members by lock. */
911 #define	__guarded_by(x)		__lock_annotate(guarded_by(x))
912 #define	__pt_guarded_by(x)	__lock_annotate(pt_guarded_by(x))
913 
914 /* Alignment builtins for better type checking and improved code generation. */
915 /* Provide fallback versions for other compilers (GCC/Clang < 10): */
916 #if !__has_builtin(__builtin_is_aligned)
917 #define __builtin_is_aligned(x, align)	\
918 	(((__uintptr_t)x & ((align) - 1)) == 0)
919 #endif
920 #if !__has_builtin(__builtin_align_up)
921 #define __builtin_align_up(x, align)	\
922 	((__typeof__(x))(((__uintptr_t)(x)+((align)-1))&(~((align)-1))))
923 #endif
924 #if !__has_builtin(__builtin_align_down)
925 #define __builtin_align_down(x, align)	\
926 	((__typeof__(x))((x)&(~((align)-1))))
927 #endif
928 
929 #define __align_up(x, y) __builtin_align_up(x, y)
930 #define __align_down(x, y) __builtin_align_down(x, y)
931 #define __is_aligned(x, y) __builtin_is_aligned(x, y)
932 
933 #endif /* !_SYS_CDEFS_H_ */
934