xref: /freebsd/sys/sys/cdefs.h (revision c697fb7f)
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 /*
42  * Testing against Clang-specific extensions.
43  */
44 #ifndef	__has_attribute
45 #define	__has_attribute(x)	0
46 #endif
47 #ifndef	__has_extension
48 #define	__has_extension		__has_feature
49 #endif
50 #ifndef	__has_feature
51 #define	__has_feature(x)	0
52 #endif
53 #ifndef	__has_include
54 #define	__has_include(x)	0
55 #endif
56 #ifndef	__has_builtin
57 #define	__has_builtin(x)	0
58 #endif
59 
60 #if defined(__cplusplus)
61 #define	__BEGIN_DECLS	extern "C" {
62 #define	__END_DECLS	}
63 #else
64 #define	__BEGIN_DECLS
65 #define	__END_DECLS
66 #endif
67 
68 /*
69  * This code has been put in place to help reduce the addition of
70  * compiler specific defines in FreeBSD code.  It helps to aid in
71  * having a compiler-agnostic source tree.
72  */
73 
74 #if defined(__GNUC__) || defined(__INTEL_COMPILER)
75 
76 #if __GNUC__ >= 3 || defined(__INTEL_COMPILER)
77 #define	__GNUCLIKE_ASM 3
78 #define	__GNUCLIKE_MATH_BUILTIN_CONSTANTS
79 #else
80 #define	__GNUCLIKE_ASM 2
81 #endif
82 #define	__GNUCLIKE___TYPEOF 1
83 #define	__GNUCLIKE___OFFSETOF 1
84 #define	__GNUCLIKE___SECTION 1
85 
86 #ifndef __INTEL_COMPILER
87 #define	__GNUCLIKE_CTOR_SECTION_HANDLING 1
88 #endif
89 
90 #define	__GNUCLIKE_BUILTIN_CONSTANT_P 1
91 #if defined(__INTEL_COMPILER) && defined(__cplusplus) && \
92    __INTEL_COMPILER < 800
93 #undef __GNUCLIKE_BUILTIN_CONSTANT_P
94 #endif
95 
96 #if (__GNUC_MINOR__ > 95 || __GNUC__ >= 3)
97 #define	__GNUCLIKE_BUILTIN_VARARGS 1
98 #define	__GNUCLIKE_BUILTIN_STDARG 1
99 #define	__GNUCLIKE_BUILTIN_VAALIST 1
100 #endif
101 
102 #if defined(__GNUC__)
103 #define	__GNUC_VA_LIST_COMPATIBILITY 1
104 #endif
105 
106 /*
107  * Compiler memory barriers, specific to gcc and clang.
108  */
109 #if defined(__GNUC__)
110 #define	__compiler_membar()	__asm __volatile(" " : : : "memory")
111 #endif
112 
113 #ifndef __INTEL_COMPILER
114 #define	__GNUCLIKE_BUILTIN_NEXT_ARG 1
115 #define	__GNUCLIKE_MATH_BUILTIN_RELOPS
116 #endif
117 
118 #define	__GNUCLIKE_BUILTIN_MEMCPY 1
119 
120 /* XXX: if __GNUC__ >= 2: not tested everywhere originally, where replaced */
121 #define	__CC_SUPPORTS_INLINE 1
122 #define	__CC_SUPPORTS___INLINE 1
123 #define	__CC_SUPPORTS___INLINE__ 1
124 
125 #define	__CC_SUPPORTS___FUNC__ 1
126 #define	__CC_SUPPORTS_WARNING 1
127 
128 #define	__CC_SUPPORTS_VARADIC_XXX 1 /* see varargs.h */
129 
130 #define	__CC_SUPPORTS_DYNAMIC_ARRAY_INIT 1
131 
132 #endif /* __GNUC__ || __INTEL_COMPILER */
133 
134 /*
135  * Macro to test if we're using a specific version of gcc or later.
136  */
137 #if defined(__GNUC__) && !defined(__INTEL_COMPILER)
138 #define	__GNUC_PREREQ__(ma, mi)	\
139 	(__GNUC__ > (ma) || __GNUC__ == (ma) && __GNUC_MINOR__ >= (mi))
140 #else
141 #define	__GNUC_PREREQ__(ma, mi)	0
142 #endif
143 
144 /*
145  * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
146  * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
147  * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI
148  * mode -- there must be no spaces between its arguments, and for nested
149  * __CONCAT's, all the __CONCAT's must be at the left.  __CONCAT can also
150  * concatenate double-quoted strings produced by the __STRING macro, but
151  * this only works with ANSI C.
152  *
153  * __XSTRING is like __STRING, but it expands any macros in its argument
154  * first.  It is only available with ANSI C.
155  */
156 #if defined(__STDC__) || defined(__cplusplus)
157 #define	__P(protos)	protos		/* full-blown ANSI C */
158 #define	__CONCAT1(x,y)	x ## y
159 #define	__CONCAT(x,y)	__CONCAT1(x,y)
160 #define	__STRING(x)	#x		/* stringify without expanding x */
161 #define	__XSTRING(x)	__STRING(x)	/* expand x, then stringify */
162 
163 #define	__const		const		/* define reserved names to standard */
164 #define	__signed	signed
165 #define	__volatile	volatile
166 #if defined(__cplusplus)
167 #define	__inline	inline		/* convert to C++ keyword */
168 #else
169 #if !(defined(__CC_SUPPORTS___INLINE))
170 #define	__inline			/* delete GCC keyword */
171 #endif /* ! __CC_SUPPORTS___INLINE */
172 #endif /* !__cplusplus */
173 
174 #else	/* !(__STDC__ || __cplusplus) */
175 #define	__P(protos)	()		/* traditional C preprocessor */
176 #define	__CONCAT(x,y)	x/**/y
177 #define	__STRING(x)	"x"
178 
179 #if !defined(__CC_SUPPORTS___INLINE)
180 #define	__const				/* delete pseudo-ANSI C keywords */
181 #define	__inline
182 #define	__signed
183 #define	__volatile
184 /*
185  * In non-ANSI C environments, new programs will want ANSI-only C keywords
186  * deleted from the program and old programs will want them left alone.
187  * When using a compiler other than gcc, programs using the ANSI C keywords
188  * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS.
189  * When using "gcc -traditional", we assume that this is the intent; if
190  * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone.
191  */
192 #ifndef	NO_ANSI_KEYWORDS
193 #define	const				/* delete ANSI C keywords */
194 #define	inline
195 #define	signed
196 #define	volatile
197 #endif	/* !NO_ANSI_KEYWORDS */
198 #endif	/* !__CC_SUPPORTS___INLINE */
199 #endif	/* !(__STDC__ || __cplusplus) */
200 
201 /*
202  * Compiler-dependent macros to help declare dead (non-returning) and
203  * pure (no side effects) functions, and unused variables.  They are
204  * null except for versions of gcc that are known to support the features
205  * properly (old versions of gcc-2 supported the dead and pure features
206  * in a different (wrong) way).  If we do not provide an implementation
207  * for a given compiler, let the compile fail if it is told to use
208  * a feature that we cannot live without.
209  */
210 #define	__weak_symbol	__attribute__((__weak__))
211 #if !__GNUC_PREREQ__(2, 5) && !defined(__INTEL_COMPILER)
212 #define	__dead2
213 #define	__pure2
214 #define	__unused
215 #endif
216 #if __GNUC__ == 2 && __GNUC_MINOR__ >= 5 && __GNUC_MINOR__ < 7 && !defined(__INTEL_COMPILER)
217 #define	__dead2		__attribute__((__noreturn__))
218 #define	__pure2		__attribute__((__const__))
219 #define	__unused
220 /* XXX Find out what to do for __packed, __aligned and __section */
221 #endif
222 #if __GNUC_PREREQ__(2, 7) || defined(__INTEL_COMPILER)
223 #define	__dead2		__attribute__((__noreturn__))
224 #define	__pure2		__attribute__((__const__))
225 #define	__unused	__attribute__((__unused__))
226 #define	__used		__attribute__((__used__))
227 #define	__packed	__attribute__((__packed__))
228 #define	__aligned(x)	__attribute__((__aligned__(x)))
229 #define	__section(x)	__attribute__((__section__(x)))
230 #endif
231 #if __GNUC_PREREQ__(4, 3) || __has_attribute(__alloc_size__)
232 #define	__alloc_size(x)	__attribute__((__alloc_size__(x)))
233 #define	__alloc_size2(n, x)	__attribute__((__alloc_size__(n, x)))
234 #else
235 #define	__alloc_size(x)
236 #define	__alloc_size2(n, x)
237 #endif
238 #if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__)
239 #define	__alloc_align(x)	__attribute__((__alloc_align__(x)))
240 #else
241 #define	__alloc_align(x)
242 #endif
243 
244 #if !__GNUC_PREREQ__(2, 95)
245 #define	__alignof(x)	__offsetof(struct { char __a; x __b; }, __b)
246 #endif
247 
248 /*
249  * Keywords added in C11.
250  */
251 
252 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
253 
254 #if !__has_extension(c_alignas)
255 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
256     __has_extension(cxx_alignas)
257 #define	_Alignas(x)		alignas(x)
258 #else
259 /* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */
260 #define	_Alignas(x)		__aligned(x)
261 #endif
262 #endif
263 
264 #if defined(__cplusplus) && __cplusplus >= 201103L
265 #define	_Alignof(x)		alignof(x)
266 #else
267 #define	_Alignof(x)		__alignof(x)
268 #endif
269 
270 #if !defined(__cplusplus) && !__has_extension(c_atomic) && \
271 	!__has_extension(cxx_atomic) && !__GNUC_PREREQ__(4, 7)
272 /*
273  * No native support for _Atomic(). Place object in structure to prevent
274  * most forms of direct non-atomic access.
275  */
276 #define	_Atomic(T)		struct { T volatile __val; }
277 #endif
278 
279 #if defined(__cplusplus) && __cplusplus >= 201103L
280 #define	_Noreturn		[[noreturn]]
281 #else
282 #define	_Noreturn		__dead2
283 #endif
284 
285 #if !__has_extension(c_static_assert)
286 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
287     __has_extension(cxx_static_assert)
288 #define	_Static_assert(x, y)	static_assert(x, y)
289 #elif __GNUC_PREREQ__(4,6) && !defined(__cplusplus)
290 /* Nothing, gcc 4.6 and higher has _Static_assert built-in */
291 #elif defined(__COUNTER__)
292 #define	_Static_assert(x, y)	__Static_assert(x, __COUNTER__)
293 #define	__Static_assert(x, y)	___Static_assert(x, y)
294 #define	___Static_assert(x, y)	typedef char __assert_ ## y[(x) ? 1 : -1] \
295 				__unused
296 #else
297 #define	_Static_assert(x, y)	struct __hack
298 #endif
299 #endif
300 
301 #if !__has_extension(c_thread_local)
302 /*
303  * XXX: Some compilers (Clang 3.3, GCC 4.7) falsely announce C++11 mode
304  * without actually supporting the thread_local keyword. Don't check for
305  * the presence of C++11 when defining _Thread_local.
306  */
307 #if /* (defined(__cplusplus) && __cplusplus >= 201103L) || */ \
308     __has_extension(cxx_thread_local)
309 #define	_Thread_local		thread_local
310 #else
311 #define	_Thread_local		__thread
312 #endif
313 #endif
314 
315 #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */
316 
317 /*
318  * Emulation of C11 _Generic().  Unlike the previously defined C11
319  * keywords, it is not possible to implement this using exactly the same
320  * syntax.  Therefore implement something similar under the name
321  * __generic().  Unlike _Generic(), this macro can only distinguish
322  * between a single type, so it requires nested invocations to
323  * distinguish multiple cases.
324  */
325 
326 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \
327     __has_extension(c_generic_selections)
328 #define	__generic(expr, t, yes, no)					\
329 	_Generic(expr, t: yes, default: no)
330 #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus)
331 #define	__generic(expr, t, yes, no)					\
332 	__builtin_choose_expr(						\
333 	    __builtin_types_compatible_p(__typeof(expr), t), yes, no)
334 #endif
335 
336 /*
337  * C99 Static array indices in function parameter declarations.  Syntax such as:
338  * void bar(int myArray[static 10]);
339  * is allowed in C99 but not in C++.  Define __min_size appropriately so
340  * headers using it can be compiled in either language.  Use like this:
341  * void bar(int myArray[__min_size(10)]);
342  */
343 #if !defined(__cplusplus) && \
344     (defined(__clang__) || __GNUC_PREREQ__(4, 6)) && \
345     (!defined(__STDC_VERSION__) || (__STDC_VERSION__ >= 199901))
346 #define __min_size(x)	static (x)
347 #else
348 #define __min_size(x)	(x)
349 #endif
350 
351 #if __GNUC_PREREQ__(2, 96)
352 #define	__malloc_like	__attribute__((__malloc__))
353 #define	__pure		__attribute__((__pure__))
354 #else
355 #define	__malloc_like
356 #define	__pure
357 #endif
358 
359 #if __GNUC_PREREQ__(3, 1) || (defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 800)
360 #define	__always_inline	__attribute__((__always_inline__))
361 #else
362 #define	__always_inline
363 #endif
364 
365 #if __GNUC_PREREQ__(3, 1)
366 #define	__noinline	__attribute__ ((__noinline__))
367 #else
368 #define	__noinline
369 #endif
370 
371 #if __GNUC_PREREQ__(3, 4)
372 #define	__fastcall	__attribute__((__fastcall__))
373 #define	__result_use_check	__attribute__((__warn_unused_result__))
374 #else
375 #define	__fastcall
376 #define	__result_use_check
377 #endif
378 
379 #if __GNUC_PREREQ__(4, 1)
380 #define	__returns_twice	__attribute__((__returns_twice__))
381 #else
382 #define	__returns_twice
383 #endif
384 
385 #if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable)
386 #define	__unreachable()	__builtin_unreachable()
387 #else
388 #define	__unreachable()	((void)0)
389 #endif
390 
391 /* XXX: should use `#if __STDC_VERSION__ < 199901'. */
392 #if !__GNUC_PREREQ__(2, 7) && !defined(__INTEL_COMPILER)
393 #define	__func__	NULL
394 #endif
395 
396 #if (defined(__INTEL_COMPILER) || (defined(__GNUC__) && __GNUC__ >= 2)) && !defined(__STRICT_ANSI__) || __STDC_VERSION__ >= 199901
397 #define	__LONG_LONG_SUPPORTED
398 #endif
399 
400 /* C++11 exposes a load of C99 stuff */
401 #if defined(__cplusplus) && __cplusplus >= 201103L
402 #define	__LONG_LONG_SUPPORTED
403 #ifndef	__STDC_LIMIT_MACROS
404 #define	__STDC_LIMIT_MACROS
405 #endif
406 #ifndef	__STDC_CONSTANT_MACROS
407 #define	__STDC_CONSTANT_MACROS
408 #endif
409 #endif
410 
411 /*
412  * GCC 2.95 provides `__restrict' as an extension to C90 to support the
413  * C99-specific `restrict' type qualifier.  We happen to use `__restrict' as
414  * a way to define the `restrict' type qualifier without disturbing older
415  * software that is unaware of C99 keywords.
416  */
417 #if !(__GNUC__ == 2 && __GNUC_MINOR__ == 95)
418 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901
419 #define	__restrict
420 #else
421 #define	__restrict	restrict
422 #endif
423 #endif
424 
425 /*
426  * GNU C version 2.96 adds explicit branch prediction so that
427  * the CPU back-end can hint the processor and also so that
428  * code blocks can be reordered such that the predicted path
429  * sees a more linear flow, thus improving cache behavior, etc.
430  *
431  * The following two macros provide us with a way to utilize this
432  * compiler feature.  Use __predict_true() if you expect the expression
433  * to evaluate to true, and __predict_false() if you expect the
434  * expression to evaluate to false.
435  *
436  * A few notes about usage:
437  *
438  *	* Generally, __predict_false() error condition checks (unless
439  *	  you have some _strong_ reason to do otherwise, in which case
440  *	  document it), and/or __predict_true() `no-error' condition
441  *	  checks, assuming you want to optimize for the no-error case.
442  *
443  *	* Other than that, if you don't know the likelihood of a test
444  *	  succeeding from empirical or other `hard' evidence, don't
445  *	  make predictions.
446  *
447  *	* These are meant to be used in places that are run `a lot'.
448  *	  It is wasteful to make predictions in code that is run
449  *	  seldomly (e.g. at subsystem initialization time) as the
450  *	  basic block reordering that this affects can often generate
451  *	  larger code.
452  */
453 #if __GNUC_PREREQ__(2, 96)
454 #define	__predict_true(exp)     __builtin_expect((exp), 1)
455 #define	__predict_false(exp)    __builtin_expect((exp), 0)
456 #else
457 #define	__predict_true(exp)     (exp)
458 #define	__predict_false(exp)    (exp)
459 #endif
460 
461 #if __GNUC_PREREQ__(4, 0)
462 #define	__null_sentinel	__attribute__((__sentinel__))
463 #define	__exported	__attribute__((__visibility__("default")))
464 #define	__hidden	__attribute__((__visibility__("hidden")))
465 #else
466 #define	__null_sentinel
467 #define	__exported
468 #define	__hidden
469 #endif
470 
471 /*
472  * We define this here since <stddef.h>, <sys/queue.h>, and <sys/types.h>
473  * require it.
474  */
475 #if __GNUC_PREREQ__(4, 1)
476 #define	__offsetof(type, field)	 __builtin_offsetof(type, field)
477 #else
478 #ifndef __cplusplus
479 #define	__offsetof(type, field) \
480 	((__size_t)(__uintptr_t)((const volatile void *)&((type *)0)->field))
481 #else
482 #define	__offsetof(type, field)					\
483   (__offsetof__ (reinterpret_cast <__size_t>			\
484                  (&reinterpret_cast <const volatile char &>	\
485                   (static_cast<type *> (0)->field))))
486 #endif
487 #endif
488 #define	__rangeof(type, start, end) \
489 	(__offsetof(type, end) - __offsetof(type, start))
490 
491 /*
492  * Given the pointer x to the member m of the struct s, return
493  * a pointer to the containing structure.  When using GCC, we first
494  * assign pointer x to a local variable, to check that its type is
495  * compatible with member m.
496  */
497 #if __GNUC_PREREQ__(3, 1)
498 #define	__containerof(x, s, m) ({					\
499 	const volatile __typeof(((s *)0)->m) *__x = (x);		\
500 	__DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m));\
501 })
502 #else
503 #define	__containerof(x, s, m)						\
504 	__DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m))
505 #endif
506 
507 /*
508  * Compiler-dependent macros to declare that functions take printf-like
509  * or scanf-like arguments.  They are null except for versions of gcc
510  * that are known to support the features properly (old versions of gcc-2
511  * didn't permit keeping the keywords out of the application namespace).
512  */
513 #if !__GNUC_PREREQ__(2, 7) && !defined(__INTEL_COMPILER)
514 #define	__printflike(fmtarg, firstvararg)
515 #define	__scanflike(fmtarg, firstvararg)
516 #define	__format_arg(fmtarg)
517 #define	__strfmonlike(fmtarg, firstvararg)
518 #define	__strftimelike(fmtarg, firstvararg)
519 #else
520 #define	__printflike(fmtarg, firstvararg) \
521 	    __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
522 #define	__scanflike(fmtarg, firstvararg) \
523 	    __attribute__((__format__ (__scanf__, fmtarg, firstvararg)))
524 #define	__format_arg(fmtarg)	__attribute__((__format_arg__ (fmtarg)))
525 #define	__strfmonlike(fmtarg, firstvararg) \
526 	    __attribute__((__format__ (__strfmon__, fmtarg, firstvararg)))
527 #define	__strftimelike(fmtarg, firstvararg) \
528 	    __attribute__((__format__ (__strftime__, fmtarg, firstvararg)))
529 #endif
530 
531 /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */
532 #if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \
533     defined(__GNUC__) && !defined(__INTEL_COMPILER)
534 #define	__printf0like(fmtarg, firstvararg) \
535 	    __attribute__((__format__ (__printf0__, fmtarg, firstvararg)))
536 #else
537 #define	__printf0like(fmtarg, firstvararg)
538 #endif
539 
540 #if defined(__GNUC__) || defined(__INTEL_COMPILER)
541 #ifndef __INTEL_COMPILER
542 #define	__strong_reference(sym,aliassym)	\
543 	extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym)))
544 #endif
545 #ifdef __STDC__
546 #define	__weak_reference(sym,alias)	\
547 	__asm__(".weak " #alias);	\
548 	__asm__(".equ "  #alias ", " #sym)
549 #define	__warn_references(sym,msg)	\
550 	__asm__(".section .gnu.warning." #sym);	\
551 	__asm__(".asciz \"" msg "\"");	\
552 	__asm__(".previous")
553 #define	__sym_compat(sym,impl,verid)	\
554 	__asm__(".symver " #impl ", " #sym "@" #verid)
555 #define	__sym_default(sym,impl,verid)	\
556 	__asm__(".symver " #impl ", " #sym "@@@" #verid)
557 #else
558 #define	__weak_reference(sym,alias)	\
559 	__asm__(".weak alias");		\
560 	__asm__(".equ alias, sym")
561 #define	__warn_references(sym,msg)	\
562 	__asm__(".section .gnu.warning.sym"); \
563 	__asm__(".asciz \"msg\"");	\
564 	__asm__(".previous")
565 #define	__sym_compat(sym,impl,verid)	\
566 	__asm__(".symver impl, sym@verid")
567 #define	__sym_default(impl,sym,verid)	\
568 	__asm__(".symver impl, sym@@@verid")
569 #endif	/* __STDC__ */
570 #endif	/* __GNUC__ || __INTEL_COMPILER */
571 
572 #define	__GLOBL1(sym)	__asm__(".globl " #sym)
573 #define	__GLOBL(sym)	__GLOBL1(sym)
574 
575 #if defined(__GNUC__) || defined(__INTEL_COMPILER)
576 #define	__IDSTRING(name,string)	__asm__(".ident\t\"" string "\"")
577 #else
578 /*
579  * The following definition might not work well if used in header files,
580  * but it should be better than nothing.  If you want a "do nothing"
581  * version, then it should generate some harmless declaration, such as:
582  *    #define	__IDSTRING(name,string)	struct __hack
583  */
584 #define	__IDSTRING(name,string)	static const char name[] __unused = string
585 #endif
586 
587 /*
588  * Embed the rcs id of a source file in the resulting library.  Note that in
589  * more recent ELF binutils, we use .ident allowing the ID to be stripped.
590  * Usage:
591  *	__FBSDID("$FreeBSD$");
592  */
593 #ifndef	__FBSDID
594 #if !defined(STRIP_FBSDID)
595 #define	__FBSDID(s)	__IDSTRING(__CONCAT(__rcsid_,__LINE__),s)
596 #else
597 #define	__FBSDID(s)	struct __hack
598 #endif
599 #endif
600 
601 #ifndef	__RCSID
602 #ifndef	NO__RCSID
603 #define	__RCSID(s)	__IDSTRING(__CONCAT(__rcsid_,__LINE__),s)
604 #else
605 #define	__RCSID(s)	struct __hack
606 #endif
607 #endif
608 
609 #ifndef	__RCSID_SOURCE
610 #ifndef	NO__RCSID_SOURCE
611 #define	__RCSID_SOURCE(s)	__IDSTRING(__CONCAT(__rcsid_source_,__LINE__),s)
612 #else
613 #define	__RCSID_SOURCE(s)	struct __hack
614 #endif
615 #endif
616 
617 #ifndef	__SCCSID
618 #ifndef	NO__SCCSID
619 #define	__SCCSID(s)	__IDSTRING(__CONCAT(__sccsid_,__LINE__),s)
620 #else
621 #define	__SCCSID(s)	struct __hack
622 #endif
623 #endif
624 
625 #ifndef	__COPYRIGHT
626 #ifndef	NO__COPYRIGHT
627 #define	__COPYRIGHT(s)	__IDSTRING(__CONCAT(__copyright_,__LINE__),s)
628 #else
629 #define	__COPYRIGHT(s)	struct __hack
630 #endif
631 #endif
632 
633 #ifndef	__DECONST
634 #define	__DECONST(type, var)	((type)(__uintptr_t)(const void *)(var))
635 #endif
636 
637 #ifndef	__DEVOLATILE
638 #define	__DEVOLATILE(type, var)	((type)(__uintptr_t)(volatile void *)(var))
639 #endif
640 
641 #ifndef	__DEQUALIFY
642 #define	__DEQUALIFY(type, var)	((type)(__uintptr_t)(const volatile void *)(var))
643 #endif
644 
645 /*-
646  * The following definitions are an extension of the behavior originally
647  * implemented in <sys/_posix.h>, but with a different level of granularity.
648  * POSIX.1 requires that the macros we test be defined before any standard
649  * header file is included.
650  *
651  * Here's a quick run-down of the versions:
652  *  defined(_POSIX_SOURCE)		1003.1-1988
653  *  _POSIX_C_SOURCE == 1		1003.1-1990
654  *  _POSIX_C_SOURCE == 2		1003.2-1992 C Language Binding Option
655  *  _POSIX_C_SOURCE == 199309		1003.1b-1993
656  *  _POSIX_C_SOURCE == 199506		1003.1c-1995, 1003.1i-1995,
657  *					and the omnibus ISO/IEC 9945-1: 1996
658  *  _POSIX_C_SOURCE == 200112		1003.1-2001
659  *  _POSIX_C_SOURCE == 200809		1003.1-2008
660  *
661  * In addition, the X/Open Portability Guide, which is now the Single UNIX
662  * Specification, defines a feature-test macro which indicates the version of
663  * that specification, and which subsumes _POSIX_C_SOURCE.
664  *
665  * Our macros begin with two underscores to avoid namespace screwage.
666  */
667 
668 /* Deal with IEEE Std. 1003.1-1990, in which _POSIX_C_SOURCE == 1. */
669 #if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 1
670 #undef _POSIX_C_SOURCE		/* Probably illegal, but beyond caring now. */
671 #define	_POSIX_C_SOURCE		199009
672 #endif
673 
674 /* Deal with IEEE Std. 1003.2-1992, in which _POSIX_C_SOURCE == 2. */
675 #if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 2
676 #undef _POSIX_C_SOURCE
677 #define	_POSIX_C_SOURCE		199209
678 #endif
679 
680 /* Deal with various X/Open Portability Guides and Single UNIX Spec. */
681 #ifdef _XOPEN_SOURCE
682 #if _XOPEN_SOURCE - 0 >= 700
683 #define	__XSI_VISIBLE		700
684 #undef _POSIX_C_SOURCE
685 #define	_POSIX_C_SOURCE		200809
686 #elif _XOPEN_SOURCE - 0 >= 600
687 #define	__XSI_VISIBLE		600
688 #undef _POSIX_C_SOURCE
689 #define	_POSIX_C_SOURCE		200112
690 #elif _XOPEN_SOURCE - 0 >= 500
691 #define	__XSI_VISIBLE		500
692 #undef _POSIX_C_SOURCE
693 #define	_POSIX_C_SOURCE		199506
694 #endif
695 #endif
696 
697 /*
698  * Deal with all versions of POSIX.  The ordering relative to the tests above is
699  * important.
700  */
701 #if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE)
702 #define	_POSIX_C_SOURCE		198808
703 #endif
704 #ifdef _POSIX_C_SOURCE
705 #if _POSIX_C_SOURCE >= 200809
706 #define	__POSIX_VISIBLE		200809
707 #define	__ISO_C_VISIBLE		1999
708 #elif _POSIX_C_SOURCE >= 200112
709 #define	__POSIX_VISIBLE		200112
710 #define	__ISO_C_VISIBLE		1999
711 #elif _POSIX_C_SOURCE >= 199506
712 #define	__POSIX_VISIBLE		199506
713 #define	__ISO_C_VISIBLE		1990
714 #elif _POSIX_C_SOURCE >= 199309
715 #define	__POSIX_VISIBLE		199309
716 #define	__ISO_C_VISIBLE		1990
717 #elif _POSIX_C_SOURCE >= 199209
718 #define	__POSIX_VISIBLE		199209
719 #define	__ISO_C_VISIBLE		1990
720 #elif _POSIX_C_SOURCE >= 199009
721 #define	__POSIX_VISIBLE		199009
722 #define	__ISO_C_VISIBLE		1990
723 #else
724 #define	__POSIX_VISIBLE		198808
725 #define	__ISO_C_VISIBLE		0
726 #endif /* _POSIX_C_SOURCE */
727 #else
728 /*-
729  * Deal with _ANSI_SOURCE:
730  * If it is defined, and no other compilation environment is explicitly
731  * requested, then define our internal feature-test macros to zero.  This
732  * makes no difference to the preprocessor (undefined symbols in preprocessing
733  * expressions are defined to have value zero), but makes it more convenient for
734  * a test program to print out the values.
735  *
736  * If a program mistakenly defines _ANSI_SOURCE and some other macro such as
737  * _POSIX_C_SOURCE, we will assume that it wants the broader compilation
738  * environment (and in fact we will never get here).
739  */
740 #if defined(_ANSI_SOURCE)	/* Hide almost everything. */
741 #define	__POSIX_VISIBLE		0
742 #define	__XSI_VISIBLE		0
743 #define	__BSD_VISIBLE		0
744 #define	__ISO_C_VISIBLE		1990
745 #define	__EXT1_VISIBLE		0
746 #elif defined(_C99_SOURCE)	/* Localism to specify strict C99 env. */
747 #define	__POSIX_VISIBLE		0
748 #define	__XSI_VISIBLE		0
749 #define	__BSD_VISIBLE		0
750 #define	__ISO_C_VISIBLE		1999
751 #define	__EXT1_VISIBLE		0
752 #elif defined(_C11_SOURCE)	/* Localism to specify strict C11 env. */
753 #define	__POSIX_VISIBLE		0
754 #define	__XSI_VISIBLE		0
755 #define	__BSD_VISIBLE		0
756 #define	__ISO_C_VISIBLE		2011
757 #define	__EXT1_VISIBLE		0
758 #else				/* Default environment: show everything. */
759 #define	__POSIX_VISIBLE		200809
760 #define	__XSI_VISIBLE		700
761 #define	__BSD_VISIBLE		1
762 #define	__ISO_C_VISIBLE		2011
763 #define	__EXT1_VISIBLE		1
764 #endif
765 #endif
766 
767 /* User override __EXT1_VISIBLE */
768 #if defined(__STDC_WANT_LIB_EXT1__)
769 #undef	__EXT1_VISIBLE
770 #if __STDC_WANT_LIB_EXT1__
771 #define	__EXT1_VISIBLE		1
772 #else
773 #define	__EXT1_VISIBLE		0
774 #endif
775 #endif /* __STDC_WANT_LIB_EXT1__ */
776 
777 #if defined(__mips) || defined(__riscv) || \
778     (defined(__powerpc64__) && (!defined(_CALL_ELF) || _CALL_ELF == 1))
779 #define	__NO_TLS 1
780 #endif
781 
782 /*
783  * Old versions of GCC use non-standard ARM arch symbols; acle-compat.h
784  * translates them to __ARM_ARCH and the modern feature symbols defined by ARM.
785  */
786 #if defined(__arm__) && !defined(__ARM_ARCH)
787 #include <machine/acle-compat.h>
788 #endif
789 
790 /*
791  * Nullability qualifiers: currently only supported by Clang.
792  */
793 #if !(defined(__clang__) && __has_feature(nullability))
794 #define	_Nonnull
795 #define	_Nullable
796 #define	_Null_unspecified
797 #define	__NULLABILITY_PRAGMA_PUSH
798 #define	__NULLABILITY_PRAGMA_POP
799 #else
800 #define	__NULLABILITY_PRAGMA_PUSH _Pragma("clang diagnostic push")	\
801 	_Pragma("clang diagnostic ignored \"-Wnullability-completeness\"")
802 #define	__NULLABILITY_PRAGMA_POP _Pragma("clang diagnostic pop")
803 #endif
804 
805 /*
806  * Type Safety Checking
807  *
808  * Clang provides additional attributes to enable checking type safety
809  * properties that cannot be enforced by the C type system.
810  */
811 
812 #if __has_attribute(__argument_with_type_tag__) && \
813     __has_attribute(__type_tag_for_datatype__)
814 #define	__arg_type_tag(arg_kind, arg_idx, type_tag_idx) \
815 	    __attribute__((__argument_with_type_tag__(arg_kind, arg_idx, type_tag_idx)))
816 #define	__datatype_type_tag(kind, type) \
817 	    __attribute__((__type_tag_for_datatype__(kind, type)))
818 #else
819 #define	__arg_type_tag(arg_kind, arg_idx, type_tag_idx)
820 #define	__datatype_type_tag(kind, type)
821 #endif
822 
823 /*
824  * Lock annotations.
825  *
826  * Clang provides support for doing basic thread-safety tests at
827  * compile-time, by marking which locks will/should be held when
828  * entering/leaving a functions.
829  *
830  * Furthermore, it is also possible to annotate variables and structure
831  * members to enforce that they are only accessed when certain locks are
832  * held.
833  */
834 
835 #if __has_extension(c_thread_safety_attributes)
836 #define	__lock_annotate(x)	__attribute__((x))
837 #else
838 #define	__lock_annotate(x)
839 #endif
840 
841 /* Structure implements a lock. */
842 #define	__lockable		__lock_annotate(lockable)
843 
844 /* Function acquires an exclusive or shared lock. */
845 #define	__locks_exclusive(...) \
846 	__lock_annotate(exclusive_lock_function(__VA_ARGS__))
847 #define	__locks_shared(...) \
848 	__lock_annotate(shared_lock_function(__VA_ARGS__))
849 
850 /* Function attempts to acquire an exclusive or shared lock. */
851 #define	__trylocks_exclusive(...) \
852 	__lock_annotate(exclusive_trylock_function(__VA_ARGS__))
853 #define	__trylocks_shared(...) \
854 	__lock_annotate(shared_trylock_function(__VA_ARGS__))
855 
856 /* Function releases a lock. */
857 #define	__unlocks(...)		__lock_annotate(unlock_function(__VA_ARGS__))
858 
859 /* Function asserts that an exclusive or shared lock is held. */
860 #define	__asserts_exclusive(...) \
861 	__lock_annotate(assert_exclusive_lock(__VA_ARGS__))
862 #define	__asserts_shared(...) \
863 	__lock_annotate(assert_shared_lock(__VA_ARGS__))
864 
865 /* Function requires that an exclusive or shared lock is or is not held. */
866 #define	__requires_exclusive(...) \
867 	__lock_annotate(exclusive_locks_required(__VA_ARGS__))
868 #define	__requires_shared(...) \
869 	__lock_annotate(shared_locks_required(__VA_ARGS__))
870 #define	__requires_unlocked(...) \
871 	__lock_annotate(locks_excluded(__VA_ARGS__))
872 
873 /* Function should not be analyzed. */
874 #define	__no_lock_analysis	__lock_annotate(no_thread_safety_analysis)
875 
876 /*
877  * Function or variable should not be sanitized, i.e. by AddressSanitizer.
878  * GCC has the nosanitize attribute, but as a function attribute only, and
879  * warns on use as a variable attribute.
880  */
881 #if __has_attribute(no_sanitize) && defined(__clang__)
882 #define __nosanitizeaddress	__attribute__((no_sanitize("address")))
883 #else
884 #define __nosanitizeaddress
885 #endif
886 
887 /* Guard variables and structure members by lock. */
888 #define	__guarded_by(x)		__lock_annotate(guarded_by(x))
889 #define	__pt_guarded_by(x)	__lock_annotate(pt_guarded_by(x))
890 
891 #endif /* !_SYS_CDEFS_H_ */
892