cdefs.h revision 1.57
1/* $NetBSD: cdefs.h,v 1.57 2004/09/23 22:13:40 yamt 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#ifdef __GNUC__ 148#define __UNCONST(p) ((__typeof__(*(p)) *)(unsigned long)(p)) 149#else 150#define __UNCONST(a) ((void *)(unsigned long)(const void *)(a)) 151#endif 152 153/* 154 * GCC2 provides __extension__ to suppress warnings for various GNU C 155 * language extensions under "-ansi -pedantic". 156 */ 157#if !__GNUC_PREREQ__(2, 0) 158#define __extension__ /* delete __extension__ if non-gcc or gcc1 */ 159#endif 160 161/* 162 * GCC1 and some versions of GCC2 declare dead (non-returning) and 163 * pure (no side effects) functions using "volatile" and "const"; 164 * unfortunately, these then cause warnings under "-ansi -pedantic". 165 * GCC2 uses a new, peculiar __attribute__((attrs)) style. All of 166 * these work for GNU C++ (modulo a slight glitch in the C++ grammar 167 * in the distribution version of 2.5.5). 168 */ 169#if !__GNUC_PREREQ__(2, 5) 170#define __attribute__(x) /* delete __attribute__ if non-gcc or gcc1 */ 171#if defined(__GNUC__) && !defined(__STRICT_ANSI__) 172#define __dead __volatile 173#define __pure __const 174#endif 175#endif 176 177/* Delete pseudo-keywords wherever they are not available or needed. */ 178#ifndef __dead 179#define __dead 180#define __pure 181#endif 182 183#if __GNUC_PREREQ__(2, 7) 184#define __unused __attribute__((__unused__)) 185#else 186#define __unused /* delete */ 187#endif 188 189#if __GNUC_PREREQ__(3, 1) 190#define __used __attribute__((__used__)) 191#else 192#define __used /* delete */ 193#endif 194 195#if __GNUC_PREREQ__(2, 7) 196#define __packed __attribute__((__packed__)) 197#define __aligned(x) __attribute__((__aligned__(x))) 198#define __section(x) __attribute__((__section__(x))) 199#elif defined(__lint__) 200#define __packed /* delete */ 201#define __aligned(x) /* delete */ 202#define __section(x) /* delete */ 203#else 204#define __packed error: no __packed for this compiler 205#define __aligned(x) error: no __aligned for this compiler 206#define __section(x) error: no __section for this compiler 207#endif 208 209/* 210 * C99 defines the restrict type qualifier keyword, which was made available 211 * in GCC 2.92. 212 */ 213#if __STDC_VERSION__ >= 199901L 214#define __restrict restrict 215#else 216#if !__GNUC_PREREQ__(2, 92) 217#define __restrict /* delete __restrict when not supported */ 218#endif 219#endif 220 221/* 222 * C99 defines __func__ predefined identifier, which was made available 223 * in GCC 2.95. 224 */ 225#if !(__STDC_VERSION__ >= 199901L) 226#if __GNUC_PREREQ__(2, 6) 227#define __func__ __PRETTY_FUNCTION__ 228#elif __GNUC_PREREQ__(2, 4) 229#define __func__ __FUNCTION__ 230#else 231#define __func__ "" 232#endif 233#endif /* !(__STDC_VERSION__ >= 199901L) */ 234 235#if defined(_KERNEL) 236#if defined(NO_KERNEL_RCSIDS) 237#undef __KERNEL_RCSID 238#define __KERNEL_RCSID(_n, _s) /* nothing */ 239#endif /* NO_KERNEL_RCSIDS */ 240#endif /* _KERNEL */ 241 242#if !defined(_STANDALONE) && !defined(_KERNEL) 243#ifdef __GNUC__ 244#define __RENAME(x) ___RENAME(x) 245#else 246#ifdef __lint__ 247#define __RENAME(x) __symbolrename(x) 248#else 249#error "No function renaming possible" 250#endif /* __lint__ */ 251#endif /* __GNUC__ */ 252#else /* _STANDALONE || _KERNEL */ 253#define __RENAME(x) no renaming in kernel or standalone environment 254#endif 255 256/* 257 * A barrier to stop the optimizer from moving code or assume live 258 * register values. This is gcc specific, the version is more or less 259 * arbitrary, might work with older compilers. 260 */ 261#if __GNUC_PREREQ__(2, 95) 262#define __insn_barrier() __asm __volatile("":::"memory") 263#else 264#define __insn_barrier() /* */ 265#endif 266 267/* 268 * GNU C version 2.96 adds explicit branch prediction so that 269 * the CPU back-end can hint the processor and also so that 270 * code blocks can be reordered such that the predicted path 271 * sees a more linear flow, thus improving cache behavior, etc. 272 * 273 * The following two macros provide us with a way to use this 274 * compiler feature. Use __predict_true() if you expect the expression 275 * to evaluate to true, and __predict_false() if you expect the 276 * expression to evaluate to false. 277 * 278 * A few notes about usage: 279 * 280 * * Generally, __predict_false() error condition checks (unless 281 * you have some _strong_ reason to do otherwise, in which case 282 * document it), and/or __predict_true() `no-error' condition 283 * checks, assuming you want to optimize for the no-error case. 284 * 285 * * Other than that, if you don't know the likelihood of a test 286 * succeeding from empirical or other `hard' evidence, don't 287 * make predictions. 288 * 289 * * These are meant to be used in places that are run `a lot'. 290 * It is wasteful to make predictions in code that is run 291 * seldomly (e.g. at subsystem initialization time) as the 292 * basic block reordering that this affects can often generate 293 * larger code. 294 */ 295#if __GNUC_PREREQ__(2, 96) 296#define __predict_true(exp) __builtin_expect((exp) != 0, 1) 297#define __predict_false(exp) __builtin_expect((exp) != 0, 0) 298#else 299#define __predict_true(exp) (exp) 300#define __predict_false(exp) (exp) 301#endif 302 303/* 304 * Macros for manipulating "link sets". Link sets are arrays of pointers 305 * to objects, which are gathered up by the linker. 306 * 307 * Object format-specific code has provided us with the following macros: 308 * 309 * __link_set_add_text(set, sym) 310 * Add a reference to the .text symbol `sym' to `set'. 311 * 312 * __link_set_add_rodata(set, sym) 313 * Add a reference to the .rodata symbol `sym' to `set'. 314 * 315 * __link_set_add_data(set, sym) 316 * Add a reference to the .data symbol `sym' to `set'. 317 * 318 * __link_set_add_bss(set, sym) 319 * Add a reference to the .bss symbol `sym' to `set'. 320 * 321 * __link_set_decl(set, ptype) 322 * Provide an extern declaration of the set `set', which 323 * contains an array of the pointer type `ptype'. This 324 * macro must be used by any code which wishes to reference 325 * the elements of a link set. 326 * 327 * __link_set_start(set) 328 * This points to the first slot in the link set. 329 * 330 * __link_set_end(set) 331 * This points to the (non-existent) slot after the last 332 * entry in the link set. 333 * 334 * __link_set_count(set) 335 * Count the number of entries in link set `set'. 336 * 337 * In addition, we provide the following macros for accessing link sets: 338 * 339 * __link_set_foreach(pvar, set) 340 * Iterate over the link set `set'. Because a link set is 341 * an array of pointers, pvar must be declared as "type **pvar", 342 * and the actual entry accessed as "*pvar". 343 * 344 * __link_set_entry(set, idx) 345 * Access the link set entry at index `idx' from set `set'. 346 */ 347#define __link_set_foreach(pvar, set) \ 348 for (pvar = __link_set_start(set); pvar < __link_set_end(set); pvar++) 349 350#define __link_set_entry(set, idx) (__link_set_begin(set)[idx]) 351 352#endif /* !_SYS_CDEFS_H_ */ 353