FreeBSD/Linux Kernel Cross Reference
sys/sys/cdefs.h
1 /* $NetBSD: cdefs.h,v 1.64 2006/11/13 05:44:37 dyoung Exp $ */
2
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 */
36
37 #ifndef _SYS_CDEFS_H_
38 #define _SYS_CDEFS_H_
39
40 /*
41 * Macro to test if we're using a GNU C compiler of a specific vintage
42 * or later, for e.g. features that appeared in a particular version
43 * of GNU C. Usage:
44 *
45 * #if __GNUC_PREREQ__(major, minor)
46 * ...cool feature...
47 * #else
48 * ...delete feature...
49 * #endif
50 */
51 #ifdef __GNUC__
52 #define __GNUC_PREREQ__(x, y) \
53 ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) || \
54 (__GNUC__ > (x)))
55 #else
56 #define __GNUC_PREREQ__(x, y) 0
57 #endif
58
59 #include <machine/cdefs.h>
60 #ifdef __ELF__
61 #include <sys/cdefs_elf.h>
62 #else
63 #include <sys/cdefs_aout.h>
64 #endif
65
66 #if defined(__cplusplus)
67 #define __BEGIN_DECLS extern "C" {
68 #define __END_DECLS }
69 #define __static_cast(x,y) static_cast<x>(y)
70 #else
71 #define __BEGIN_DECLS
72 #define __END_DECLS
73 #define __static_cast(x,y) (x)y
74 #endif
75
76 /*
77 * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
78 * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
79 * The __CONCAT macro is a bit tricky -- make sure you don't put spaces
80 * in between its arguments. __CONCAT can also concatenate double-quoted
81 * strings produced by the __STRING macro, but this only works with ANSI C.
82 */
83
84 #define ___STRING(x) __STRING(x)
85 #define ___CONCAT(x,y) __CONCAT(x,y)
86
87 #if __STDC__ || defined(__cplusplus)
88 #define __P(protos) protos /* full-blown ANSI C */
89 #define __CONCAT(x,y) x ## y
90 #define __STRING(x) #x
91
92 #define __const const /* define reserved names to standard */
93 #define __signed signed
94 #define __volatile volatile
95 #if defined(__cplusplus)
96 #define __inline inline /* convert to C++ keyword */
97 #else
98 #if !defined(__GNUC__) && !defined(__lint__)
99 #define __inline /* delete GCC keyword */
100 #endif /* !__GNUC__ && !__lint__ */
101 #endif /* !__cplusplus */
102
103 #else /* !(__STDC__ || __cplusplus) */
104 #define __P(protos) () /* traditional C preprocessor */
105 #define __CONCAT(x,y) x/**/y
106 #define __STRING(x) "x"
107
108 #ifndef __GNUC__
109 #define __const /* delete pseudo-ANSI C keywords */
110 #define __inline
111 #define __signed
112 #define __volatile
113 #endif /* !__GNUC__ */
114
115 /*
116 * In non-ANSI C environments, new programs will want ANSI-only C keywords
117 * deleted from the program and old programs will want them left alone.
118 * Programs using the ANSI C keywords const, inline etc. as normal
119 * identifiers should define -DNO_ANSI_KEYWORDS.
120 */
121 #ifndef NO_ANSI_KEYWORDS
122 #define const __const /* convert ANSI C keywords */
123 #define inline __inline
124 #define signed __signed
125 #define volatile __volatile
126 #endif /* !NO_ANSI_KEYWORDS */
127 #endif /* !(__STDC__ || __cplusplus) */
128
129 /*
130 * Used for internal auditing of the NetBSD source tree.
131 */
132 #ifdef __AUDIT__
133 #define __aconst __const
134 #else
135 #define __aconst
136 #endif
137
138 /*
139 * The following macro is used to remove const cast-away warnings
140 * from gcc -Wcast-qual; it should be used with caution because it
141 * can hide valid errors; in particular most valid uses are in
142 * situations where the API requires it, not to cast away string
143 * constants. We don't use *intptr_t on purpose here and we are
144 * explicit about unsigned long so that we don't have additional
145 * dependencies.
146 */
147 #define __UNCONST(a) ((void *)(unsigned long)(const void *)(a))
148
149 /*
150 * The following macro is used to remove the volatile cast-away warnings
151 * from gcc -Wcast-qual; as above it should be used with caution
152 * because it can hide valid errors or warnings. Valid uses include
153 * making it possible to pass a volatile pointer to memset().
154 * For the same reasons as above, we use unsigned long and not intptr_t.
155 */
156 #define __UNVOLATILE(a) ((void *)(unsigned long)(volatile void *)(a))
157
158 /*
159 * GCC2 provides __extension__ to suppress warnings for various GNU C
160 * language extensions under "-ansi -pedantic".
161 */
162 #if !__GNUC_PREREQ__(2, 0)
163 #define __extension__ /* delete __extension__ if non-gcc or gcc1 */
164 #endif
165
166 /*
167 * GCC1 and some versions of GCC2 declare dead (non-returning) and
168 * pure (no side effects) functions using "volatile" and "const";
169 * unfortunately, these then cause warnings under "-ansi -pedantic".
170 * GCC2 uses a new, peculiar __attribute__((attrs)) style. All of
171 * these work for GNU C++ (modulo a slight glitch in the C++ grammar
172 * in the distribution version of 2.5.5).
173 */
174 #if !__GNUC_PREREQ__(2, 5)
175 #define __attribute__(x) /* delete __attribute__ if non-gcc or gcc1 */
176 #if defined(__GNUC__) && !defined(__STRICT_ANSI__)
177 #define __dead __volatile
178 #define __pure __const
179 #endif
180 #endif
181
182 /* Delete pseudo-keywords wherever they are not available or needed. */
183 #ifndef __dead
184 #define __dead
185 #define __pure
186 #endif
187
188 #if __GNUC_PREREQ__(2, 7)
189 #define __unused __attribute__((__unused__))
190 #else
191 #define __unused /* delete */
192 #endif
193
194 #if __GNUC_PREREQ__(3, 1)
195 #define __used __attribute__((__used__))
196 #else
197 #define __used __unused
198 #endif
199
200 #if __GNUC_PREREQ__(2, 7)
201 #define __packed __attribute__((__packed__))
202 #define __aligned(x) __attribute__((__aligned__(x)))
203 #define __section(x) __attribute__((__section__(x)))
204 #elif defined(__lint__)
205 #define __packed /* delete */
206 #define __aligned(x) /* delete */
207 #define __section(x) /* delete */
208 #else
209 #define __packed error: no __packed for this compiler
210 #define __aligned(x) error: no __aligned for this compiler
211 #define __section(x) error: no __section for this compiler
212 #endif
213
214 /*
215 * C99 defines the restrict type qualifier keyword, which was made available
216 * in GCC 2.92.
217 */
218 #if __STDC_VERSION__ >= 199901L
219 #define __restrict restrict
220 #else
221 #if !__GNUC_PREREQ__(2, 92)
222 #define __restrict /* delete __restrict when not supported */
223 #endif
224 #endif
225
226 /*
227 * C99 defines __func__ predefined identifier, which was made available
228 * in GCC 2.95.
229 */
230 #if !(__STDC_VERSION__ >= 199901L)
231 #if __GNUC_PREREQ__(2, 6)
232 #define __func__ __PRETTY_FUNCTION__
233 #elif __GNUC_PREREQ__(2, 4)
234 #define __func__ __FUNCTION__
235 #else
236 #define __func__ ""
237 #endif
238 #endif /* !(__STDC_VERSION__ >= 199901L) */
239
240 #if defined(_KERNEL)
241 #if defined(NO_KERNEL_RCSIDS)
242 #undef __KERNEL_RCSID
243 #define __KERNEL_RCSID(_n, _s) /* nothing */
244 #endif /* NO_KERNEL_RCSIDS */
245 #endif /* _KERNEL */
246
247 #if !defined(_STANDALONE) && !defined(_KERNEL)
248 #ifdef __GNUC__
249 #define __RENAME(x) ___RENAME(x)
250 #else
251 #ifdef __lint__
252 #define __RENAME(x) __symbolrename(x)
253 #else
254 #error "No function renaming possible"
255 #endif /* __lint__ */
256 #endif /* __GNUC__ */
257 #else /* _STANDALONE || _KERNEL */
258 #define __RENAME(x) no renaming in kernel or standalone environment
259 #endif
260
261 /*
262 * A barrier to stop the optimizer from moving code or assume live
263 * register values. This is gcc specific, the version is more or less
264 * arbitrary, might work with older compilers.
265 */
266 #if __GNUC_PREREQ__(2, 95)
267 #define __insn_barrier() __asm __volatile("":::"memory")
268 #else
269 #define __insn_barrier() /* */
270 #endif
271
272 /*
273 * GNU C version 2.96 adds explicit branch prediction so that
274 * the CPU back-end can hint the processor and also so that
275 * code blocks can be reordered such that the predicted path
276 * sees a more linear flow, thus improving cache behavior, etc.
277 *
278 * The following two macros provide us with a way to use this
279 * compiler feature. Use __predict_true() if you expect the expression
280 * to evaluate to true, and __predict_false() if you expect the
281 * expression to evaluate to false.
282 *
283 * A few notes about usage:
284 *
285 * * Generally, __predict_false() error condition checks (unless
286 * you have some _strong_ reason to do otherwise, in which case
287 * document it), and/or __predict_true() `no-error' condition
288 * checks, assuming you want to optimize for the no-error case.
289 *
290 * * Other than that, if you don't know the likelihood of a test
291 * succeeding from empirical or other `hard' evidence, don't
292 * make predictions.
293 *
294 * * These are meant to be used in places that are run `a lot'.
295 * It is wasteful to make predictions in code that is run
296 * seldomly (e.g. at subsystem initialization time) as the
297 * basic block reordering that this affects can often generate
298 * larger code.
299 */
300 #if __GNUC_PREREQ__(2, 96)
301 #define __predict_true(exp) __builtin_expect((exp) != 0, 1)
302 #define __predict_false(exp) __builtin_expect((exp) != 0, 0)
303 #else
304 #define __predict_true(exp) (exp)
305 #define __predict_false(exp) (exp)
306 #endif
307
308 /*
309 * Macros for manipulating "link sets". Link sets are arrays of pointers
310 * to objects, which are gathered up by the linker.
311 *
312 * Object format-specific code has provided us with the following macros:
313 *
314 * __link_set_add_text(set, sym)
315 * Add a reference to the .text symbol `sym' to `set'.
316 *
317 * __link_set_add_rodata(set, sym)
318 * Add a reference to the .rodata symbol `sym' to `set'.
319 *
320 * __link_set_add_data(set, sym)
321 * Add a reference to the .data symbol `sym' to `set'.
322 *
323 * __link_set_add_bss(set, sym)
324 * Add a reference to the .bss symbol `sym' to `set'.
325 *
326 * __link_set_decl(set, ptype)
327 * Provide an extern declaration of the set `set', which
328 * contains an array of the pointer type `ptype'. This
329 * macro must be used by any code which wishes to reference
330 * the elements of a link set.
331 *
332 * __link_set_start(set)
333 * This points to the first slot in the link set.
334 *
335 * __link_set_end(set)
336 * This points to the (non-existent) slot after the last
337 * entry in the link set.
338 *
339 * __link_set_count(set)
340 * Count the number of entries in link set `set'.
341 *
342 * In addition, we provide the following macros for accessing link sets:
343 *
344 * __link_set_foreach(pvar, set)
345 * Iterate over the link set `set'. Because a link set is
346 * an array of pointers, pvar must be declared as "type **pvar",
347 * and the actual entry accessed as "*pvar".
348 *
349 * __link_set_entry(set, idx)
350 * Access the link set entry at index `idx' from set `set'.
351 */
352 #define __link_set_foreach(pvar, set) \
353 for (pvar = __link_set_start(set); pvar < __link_set_end(set); pvar++)
354
355 #define __link_set_entry(set, idx) (__link_set_begin(set)[idx])
356
357 /*
358 * Return the number of elements in a statically-allocated array,
359 * __x.
360 */
361 #define __arraycount(__x) (sizeof(__x) / sizeof(__x[0]))
362
363 /* __BIT(n): nth bit, where __BIT(0) == 0x1. */
364 #define __BIT(__n) \
365 (((__n) >= NBBY * sizeof(uintmax_t)) ? 0 : ((uintmax_t)1 << (__n)))
366
367 /* __BITS(m, n): bits m through n, m < n. */
368 #define __BITS(__m, __n) \
369 ((__BIT(MAX((__m), (__n)) + 1) - 1) ^ (__BIT(MIN((__m), (__n))) - 1))
370
371 /* find least significant bit that is set */
372 #define __LOWEST_SET_BIT(__mask) ((((__mask) - 1) & (__mask)) ^ (__mask))
373
374 #define __PRIuBIT PRIuMAX
375 #define __PRIuBITS __PRIuBIT
376
377 #define __PRIxBIT PRIxMAX
378 #define __PRIxBITS __PRIxBIT
379
380 #define __SHIFTOUT(__x, __mask) (((__x) & (__mask)) / __LOWEST_SET_BIT(__mask))
381 #define __SHIFTIN(__x, __mask) ((__x) * __LOWEST_SET_BIT(__mask))
382 #define __SHIFTOUT_MASK(__mask) __SHIFTOUT((__mask), (__mask))
383
384 #endif /* !_SYS_CDEFS_H_ */
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