cdefs.h revision 1.59
1/* $NetBSD: cdefs.h,v 1.59 2005/06/02 14:31:38 he 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 /* delete */ 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#endif /* !_SYS_CDEFS_H_ */ 358