cdefs.h revision 1.70
1/* $NetBSD: cdefs.h,v 1.70 2008/12/10 22:10:47 alc 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) || defined(__PCC__) 96#define __inline inline /* convert to C++/C99 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, 0) 175#define __attribute__(x) 176#endif 177 178#if __GNUC_PREREQ__(2, 5) 179#define __dead __attribute__((__noreturn__)) 180#elif defined(__GNUC__) 181#define __dead __volatile 182#else 183#define __dead 184#endif 185 186#if __GNUC_PREREQ__(2, 96) 187#define __pure __attribute__((__pure__)) 188#elif defined(__GNUC__) 189#define __pure __const 190#else 191#define __pure 192#endif 193 194#if __GNUC_PREREQ__(3, 0) 195#define __noinline __attribute__((__noinline__)) 196#else 197#define __noinline /* nothing */ 198#endif 199 200#if __GNUC_PREREQ__(2, 7) 201#define __unused __attribute__((__unused__)) 202#else 203#define __unused /* delete */ 204#endif 205 206#if __GNUC_PREREQ__(3, 1) 207#define __used __attribute__((__used__)) 208#else 209#define __used __unused 210#endif 211 212#if __GNUC_PREREQ__(2, 7) 213#define __packed __attribute__((__packed__)) 214#define __aligned(x) __attribute__((__aligned__(x))) 215#define __section(x) __attribute__((__section__(x))) 216#elif defined(__PCC__) 217#define __packed _Pragma("packed") 218#define __aligned(x) _Pragma("aligned " #x) 219#define __section(x) _Pragma("section " ## x) 220#elif defined(__lint__) 221#define __packed /* delete */ 222#define __aligned(x) /* delete */ 223#define __section(x) /* delete */ 224#else 225#define __packed error: no __packed for this compiler 226#define __aligned(x) error: no __aligned for this compiler 227#define __section(x) error: no __section for this compiler 228#endif 229 230/* 231 * C99 defines the restrict type qualifier keyword, which was made available 232 * in GCC 2.92. 233 */ 234#if defined(__lint__) 235#define __restrict /* delete __restrict when not supported */ 236#elif __STDC_VERSION__ >= 199901L 237#define __restrict restrict 238#elif !__GNUC_PREREQ__(2, 92) 239#define __restrict /* delete __restrict when not supported */ 240#endif 241 242/* 243 * C99 defines __func__ predefined identifier, which was made available 244 * in GCC 2.95. 245 */ 246#if !(__STDC_VERSION__ >= 199901L) 247#if __GNUC_PREREQ__(2, 6) 248#define __func__ __PRETTY_FUNCTION__ 249#elif __GNUC_PREREQ__(2, 4) 250#define __func__ __FUNCTION__ 251#else 252#define __func__ "" 253#endif 254#endif /* !(__STDC_VERSION__ >= 199901L) */ 255 256#if defined(_KERNEL) 257#if defined(NO_KERNEL_RCSIDS) 258#undef __KERNEL_RCSID 259#define __KERNEL_RCSID(_n, _s) /* nothing */ 260#endif /* NO_KERNEL_RCSIDS */ 261#endif /* _KERNEL */ 262 263#if !defined(_STANDALONE) && !defined(_KERNEL) 264#if defined(__GNUC__) || defined(__PCC__) 265#define __RENAME(x) ___RENAME(x) 266#else 267#ifdef __lint__ 268#define __RENAME(x) __symbolrename(x) 269#else 270#error "No function renaming possible" 271#endif /* __lint__ */ 272#endif /* __GNUC__ */ 273#else /* _STANDALONE || _KERNEL */ 274#define __RENAME(x) no renaming in kernel or standalone environment 275#endif 276 277/* 278 * A barrier to stop the optimizer from moving code or assume live 279 * register values. This is gcc specific, the version is more or less 280 * arbitrary, might work with older compilers. 281 */ 282#if __GNUC_PREREQ__(2, 95) 283#define __insn_barrier() __asm __volatile("":::"memory") 284#else 285#define __insn_barrier() /* */ 286#endif 287 288/* 289 * GNU C version 2.96 adds explicit branch prediction so that 290 * the CPU back-end can hint the processor and also so that 291 * code blocks can be reordered such that the predicted path 292 * sees a more linear flow, thus improving cache behavior, etc. 293 * 294 * The following two macros provide us with a way to use this 295 * compiler feature. Use __predict_true() if you expect the expression 296 * to evaluate to true, and __predict_false() if you expect the 297 * expression to evaluate to false. 298 * 299 * A few notes about usage: 300 * 301 * * Generally, __predict_false() error condition checks (unless 302 * you have some _strong_ reason to do otherwise, in which case 303 * document it), and/or __predict_true() `no-error' condition 304 * checks, assuming you want to optimize for the no-error case. 305 * 306 * * Other than that, if you don't know the likelihood of a test 307 * succeeding from empirical or other `hard' evidence, don't 308 * make predictions. 309 * 310 * * These are meant to be used in places that are run `a lot'. 311 * It is wasteful to make predictions in code that is run 312 * seldomly (e.g. at subsystem initialization time) as the 313 * basic block reordering that this affects can often generate 314 * larger code. 315 */ 316#if __GNUC_PREREQ__(2, 96) 317#define __predict_true(exp) __builtin_expect((exp) != 0, 1) 318#define __predict_false(exp) __builtin_expect((exp) != 0, 0) 319#else 320#define __predict_true(exp) (exp) 321#define __predict_false(exp) (exp) 322#endif 323 324/* 325 * Compiler-dependent macros to declare that functions take printf-like 326 * or scanf-like arguments. They are null except for versions of gcc 327 * that are known to support the features properly (old versions of gcc-2 328 * didn't permit keeping the keywords out of the application namespace). 329 */ 330#if __GNUC_PREREQ__(2, 7) 331#define __printflike(fmtarg, firstvararg) \ 332 __attribute__((__format__ (__printf__, fmtarg, firstvararg))) 333#define __scanflike(fmtarg, firstvararg) \ 334 __attribute__((__format__ (__scanf__, fmtarg, firstvararg))) 335#define __format_arg(fmtarg) __attribute__((__format_arg__ (fmtarg))) 336#else 337#define __printflike(fmtarg, firstvararg) /* nothing */ 338#define __scanflike(fmtarg, firstvararg) /* nothing */ 339#define __format_arg(fmtarg) /* nothing */ 340#endif 341 342/* 343 * Macros for manipulating "link sets". Link sets are arrays of pointers 344 * to objects, which are gathered up by the linker. 345 * 346 * Object format-specific code has provided us with the following macros: 347 * 348 * __link_set_add_text(set, sym) 349 * Add a reference to the .text symbol `sym' to `set'. 350 * 351 * __link_set_add_rodata(set, sym) 352 * Add a reference to the .rodata symbol `sym' to `set'. 353 * 354 * __link_set_add_data(set, sym) 355 * Add a reference to the .data symbol `sym' to `set'. 356 * 357 * __link_set_add_bss(set, sym) 358 * Add a reference to the .bss symbol `sym' to `set'. 359 * 360 * __link_set_decl(set, ptype) 361 * Provide an extern declaration of the set `set', which 362 * contains an array of the pointer type `ptype'. This 363 * macro must be used by any code which wishes to reference 364 * the elements of a link set. 365 * 366 * __link_set_start(set) 367 * This points to the first slot in the link set. 368 * 369 * __link_set_end(set) 370 * This points to the (non-existent) slot after the last 371 * entry in the link set. 372 * 373 * __link_set_count(set) 374 * Count the number of entries in link set `set'. 375 * 376 * In addition, we provide the following macros for accessing link sets: 377 * 378 * __link_set_foreach(pvar, set) 379 * Iterate over the link set `set'. Because a link set is 380 * an array of pointers, pvar must be declared as "type **pvar", 381 * and the actual entry accessed as "*pvar". 382 * 383 * __link_set_entry(set, idx) 384 * Access the link set entry at index `idx' from set `set'. 385 */ 386#define __link_set_foreach(pvar, set) \ 387 for (pvar = __link_set_start(set); pvar < __link_set_end(set); pvar++) 388 389#define __link_set_entry(set, idx) (__link_set_begin(set)[idx]) 390 391/* 392 * Return the number of elements in a statically-allocated array, 393 * __x. 394 */ 395#define __arraycount(__x) (sizeof(__x) / sizeof(__x[0])) 396 397/* __BIT(n): nth bit, where __BIT(0) == 0x1. */ 398#define __BIT(__n) \ 399 (((__n) >= NBBY * sizeof(uintmax_t)) ? 0 : ((uintmax_t)1 << (__n))) 400 401/* __BITS(m, n): bits m through n, m < n. */ 402#define __BITS(__m, __n) \ 403 ((__BIT(MAX((__m), (__n)) + 1) - 1) ^ (__BIT(MIN((__m), (__n))) - 1)) 404 405/* find least significant bit that is set */ 406#define __LOWEST_SET_BIT(__mask) ((((__mask) - 1) & (__mask)) ^ (__mask)) 407 408#define __PRIuBIT PRIuMAX 409#define __PRIuBITS __PRIuBIT 410 411#define __PRIxBIT PRIxMAX 412#define __PRIxBITS __PRIxBIT 413 414#define __SHIFTOUT(__x, __mask) (((__x) & (__mask)) / __LOWEST_SET_BIT(__mask)) 415#define __SHIFTIN(__x, __mask) ((__x) * __LOWEST_SET_BIT(__mask)) 416#define __SHIFTOUT_MASK(__mask) __SHIFTOUT((__mask), (__mask)) 417 418#endif /* !_SYS_CDEFS_H_ */ 419