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 35 #ifndef _SYS_CDEFS_H_ 36 #define _SYS_CDEFS_H_ 37 38 #if defined(_KERNEL) && defined(_STANDALONE) 39 #error "_KERNEL and _STANDALONE are mutually exclusive" 40 #endif 41 42 /* 43 * Testing against Clang-specific extensions. 44 */ 45 #ifndef __has_attribute 46 #define __has_attribute(x) 0 47 #endif 48 #ifndef __has_extension 49 #define __has_extension __has_feature 50 #endif 51 #ifndef __has_feature 52 #define __has_feature(x) 0 53 #endif 54 #ifndef __has_include 55 #define __has_include(x) 0 56 #endif 57 #ifndef __has_builtin 58 #define __has_builtin(x) 0 59 #endif 60 61 #if defined(__cplusplus) 62 #define __BEGIN_DECLS extern "C" { 63 #define __END_DECLS } 64 #else 65 #define __BEGIN_DECLS 66 #define __END_DECLS 67 #endif 68 69 /* 70 * This code has been put in place to help reduce the addition of 71 * compiler specific defines in FreeBSD code. It helps to aid in 72 * having a compiler-agnostic source tree. 73 */ 74 75 /* 76 * Macro to test if we're using a specific version of gcc or later. 77 */ 78 #if defined(__GNUC__) 79 #define __GNUC_PREREQ__(ma, mi) \ 80 (__GNUC__ > (ma) || __GNUC__ == (ma) && __GNUC_MINOR__ >= (mi)) 81 #else 82 #define __GNUC_PREREQ__(ma, mi) 0 83 #endif 84 85 #if defined(__GNUC__) 86 87 /* 88 * Compiler memory barriers, specific to gcc and clang. 89 */ 90 #define __compiler_membar() __asm __volatile(" " : : : "memory") 91 92 #define __CC_SUPPORTS___INLINE 1 93 94 #endif /* __GNUC__ */ 95 96 /* 97 * The __CONCAT macro is used to concatenate parts of symbol names, e.g. 98 * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo. 99 * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI 100 * mode -- there must be no spaces between its arguments, and for nested 101 * __CONCAT's, all the __CONCAT's must be at the left. __CONCAT can also 102 * concatenate double-quoted strings produced by the __STRING macro, but 103 * this only works with ANSI C. 104 * 105 * __XSTRING is like __STRING, but it expands any macros in its argument 106 * first. It is only available with ANSI C. 107 */ 108 #if defined(__STDC__) || defined(__cplusplus) 109 #define __P(protos) protos /* full-blown ANSI C */ 110 #define __CONCAT1(x,y) x ## y 111 #define __CONCAT(x,y) __CONCAT1(x,y) 112 #define __STRING(x) #x /* stringify without expanding x */ 113 #define __XSTRING(x) __STRING(x) /* expand x, then stringify */ 114 115 #define __const const /* define reserved names to standard */ 116 #define __signed signed 117 #define __volatile volatile 118 #if defined(__cplusplus) 119 #define __inline inline /* convert to C++ keyword */ 120 #else 121 #if !(defined(__CC_SUPPORTS___INLINE)) 122 #define __inline /* delete GCC keyword */ 123 #endif /* ! __CC_SUPPORTS___INLINE */ 124 #endif /* !__cplusplus */ 125 126 #else /* !(__STDC__ || __cplusplus) */ 127 #define __P(protos) () /* traditional C preprocessor */ 128 #define __CONCAT(x,y) x/**/y 129 #define __STRING(x) "x" 130 131 #if !defined(__CC_SUPPORTS___INLINE) 132 #define __const /* delete pseudo-ANSI C keywords */ 133 #define __inline 134 #define __signed 135 #define __volatile 136 /* 137 * In non-ANSI C environments, new programs will want ANSI-only C keywords 138 * deleted from the program and old programs will want them left alone. 139 * When using a compiler other than gcc, programs using the ANSI C keywords 140 * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS. 141 * When using "gcc -traditional", we assume that this is the intent; if 142 * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone. 143 */ 144 #ifndef NO_ANSI_KEYWORDS 145 #define const /* delete ANSI C keywords */ 146 #define inline 147 #define signed 148 #define volatile 149 #endif /* !NO_ANSI_KEYWORDS */ 150 #endif /* !__CC_SUPPORTS___INLINE */ 151 #endif /* !(__STDC__ || __cplusplus) */ 152 153 /* 154 * Compiler-dependent macros to help declare dead (non-returning) and 155 * pure (no side effects) functions, and unused variables. They are 156 * null except for versions of gcc that are known to support the features 157 * properly (old versions of gcc-2 supported the dead and pure features 158 * in a different (wrong) way). If we do not provide an implementation 159 * for a given compiler, let the compile fail if it is told to use 160 * a feature that we cannot live without. 161 */ 162 #define __weak_symbol __attribute__((__weak__)) 163 #if !__GNUC_PREREQ__(2, 5) 164 #define __dead2 165 #define __pure2 166 #define __unused 167 #endif 168 #if __GNUC__ == 2 && __GNUC_MINOR__ >= 5 && __GNUC_MINOR__ < 7 169 #define __dead2 __attribute__((__noreturn__)) 170 #define __pure2 __attribute__((__const__)) 171 #define __unused 172 /* XXX Find out what to do for __packed, __aligned and __section */ 173 #endif 174 #if __GNUC_PREREQ__(2, 7) 175 #define __dead2 __attribute__((__noreturn__)) 176 #define __pure2 __attribute__((__const__)) 177 #define __unused __attribute__((__unused__)) 178 #define __used __attribute__((__used__)) 179 #define __packed __attribute__((__packed__)) 180 #define __aligned(x) __attribute__((__aligned__(x))) 181 #define __section(x) __attribute__((__section__(x))) 182 #endif 183 #if __GNUC_PREREQ__(4, 3) || __has_attribute(__alloc_size__) 184 #define __alloc_size(x) __attribute__((__alloc_size__(x))) 185 #define __alloc_size2(n, x) __attribute__((__alloc_size__(n, x))) 186 #else 187 #define __alloc_size(x) 188 #define __alloc_size2(n, x) 189 #endif 190 #if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__) 191 #define __alloc_align(x) __attribute__((__alloc_align__(x))) 192 #else 193 #define __alloc_align(x) 194 #endif 195 196 #if !__GNUC_PREREQ__(2, 95) 197 #define __alignof(x) __offsetof(struct { char __a; x __b; }, __b) 198 #endif 199 200 /* 201 * Keywords added in C11. 202 */ 203 204 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L 205 206 #if !__has_extension(c_alignas) 207 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \ 208 __has_extension(cxx_alignas) 209 #define _Alignas(x) alignas(x) 210 #else 211 /* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */ 212 #define _Alignas(x) __aligned(x) 213 #endif 214 #endif 215 216 #if defined(__cplusplus) && __cplusplus >= 201103L 217 #define _Alignof(x) alignof(x) 218 #else 219 #define _Alignof(x) __alignof(x) 220 #endif 221 222 #if !defined(__cplusplus) && !__has_extension(c_atomic) && \ 223 !__has_extension(cxx_atomic) && !__GNUC_PREREQ__(4, 7) 224 /* 225 * No native support for _Atomic(). Place object in structure to prevent 226 * most forms of direct non-atomic access. 227 */ 228 #define _Atomic(T) struct { T volatile __val; } 229 #endif 230 231 #if defined(__cplusplus) && __cplusplus >= 201103L 232 #define _Noreturn [[noreturn]] 233 #else 234 #define _Noreturn __dead2 235 #endif 236 237 #if !__has_extension(c_static_assert) 238 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \ 239 __has_extension(cxx_static_assert) 240 #define _Static_assert(x, y) static_assert(x, y) 241 #elif __GNUC_PREREQ__(4,6) && !defined(__cplusplus) 242 /* Nothing, gcc 4.6 and higher has _Static_assert built-in */ 243 #elif defined(__COUNTER__) 244 #define _Static_assert(x, y) __Static_assert(x, __COUNTER__) 245 #define __Static_assert(x, y) ___Static_assert(x, y) 246 #define ___Static_assert(x, y) typedef char __assert_ ## y[(x) ? 1 : -1] \ 247 __unused 248 #else 249 #define _Static_assert(x, y) struct __hack 250 #endif 251 #endif 252 253 #if !__has_extension(c_thread_local) 254 /* 255 * XXX: Some compilers (Clang 3.3, GCC 4.7) falsely announce C++11 mode 256 * without actually supporting the thread_local keyword. Don't check for 257 * the presence of C++11 when defining _Thread_local. 258 */ 259 #if /* (defined(__cplusplus) && __cplusplus >= 201103L) || */ \ 260 __has_extension(cxx_thread_local) 261 #define _Thread_local thread_local 262 #else 263 #define _Thread_local __thread 264 #endif 265 #endif 266 267 #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */ 268 269 /* 270 * Emulation of C11 _Generic(). Unlike the previously defined C11 271 * keywords, it is not possible to implement this using exactly the same 272 * syntax. Therefore implement something similar under the name 273 * __generic(). Unlike _Generic(), this macro can only distinguish 274 * between a single type, so it requires nested invocations to 275 * distinguish multiple cases. 276 * 277 * Note that the comma operator is used to force expr to decay in 278 * order to match _Generic(). 279 */ 280 281 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \ 282 __has_extension(c_generic_selections) 283 #define __generic(expr, t, yes, no) \ 284 _Generic(expr, t: yes, default: no) 285 #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus) 286 #define __generic(expr, t, yes, no) \ 287 __builtin_choose_expr( \ 288 __builtin_types_compatible_p(__typeof((0, (expr))), t), yes, no) 289 #endif 290 291 /* 292 * C99 Static array indices in function parameter declarations. Syntax such as: 293 * void bar(int myArray[static 10]); 294 * is allowed in C99 but not in C++. Define __min_size appropriately so 295 * headers using it can be compiled in either language. Use like this: 296 * void bar(int myArray[__min_size(10)]); 297 */ 298 #if !defined(__cplusplus) && \ 299 (defined(__clang__) || __GNUC_PREREQ__(4, 6)) && \ 300 (!defined(__STDC_VERSION__) || (__STDC_VERSION__ >= 199901)) 301 #define __min_size(x) static (x) 302 #else 303 #define __min_size(x) (x) 304 #endif 305 306 #if __GNUC_PREREQ__(2, 96) 307 #define __malloc_like __attribute__((__malloc__)) 308 #define __pure __attribute__((__pure__)) 309 #else 310 #define __malloc_like 311 #define __pure 312 #endif 313 314 #if __GNUC_PREREQ__(3, 1) 315 #define __always_inline __attribute__((__always_inline__)) 316 #else 317 #define __always_inline 318 #endif 319 320 #if __GNUC_PREREQ__(3, 1) 321 #define __noinline __attribute__ ((__noinline__)) 322 #else 323 #define __noinline 324 #endif 325 326 #if __GNUC_PREREQ__(3, 4) 327 #define __fastcall __attribute__((__fastcall__)) 328 #define __result_use_check __attribute__((__warn_unused_result__)) 329 #else 330 #define __fastcall 331 #define __result_use_check 332 #endif 333 334 #if __GNUC_PREREQ__(4, 1) 335 #define __returns_twice __attribute__((__returns_twice__)) 336 #else 337 #define __returns_twice 338 #endif 339 340 #if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable) 341 #define __unreachable() __builtin_unreachable() 342 #else 343 #define __unreachable() ((void)0) 344 #endif 345 346 #if (defined(__GNUC__) && __GNUC__ >= 2) && !defined(__STRICT_ANSI__) || __STDC_VERSION__ >= 199901 347 #define __LONG_LONG_SUPPORTED 348 #endif 349 350 /* C++11 exposes a load of C99 stuff */ 351 #if defined(__cplusplus) && __cplusplus >= 201103L 352 #define __LONG_LONG_SUPPORTED 353 #ifndef __STDC_LIMIT_MACROS 354 #define __STDC_LIMIT_MACROS 355 #endif 356 #ifndef __STDC_CONSTANT_MACROS 357 #define __STDC_CONSTANT_MACROS 358 #endif 359 #endif 360 361 /* 362 * We use `__restrict' as a way to define the `restrict' type qualifier 363 * without disturbing older software that is unaware of C99 keywords. 364 * GCC also provides `__restrict' as an extension to support C99-style 365 * restricted pointers in other language modes. 366 */ 367 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901 368 #define __restrict restrict 369 #elif !__GNUC_PREREQ__(2, 95) 370 #define __restrict 371 #endif 372 373 /* 374 * GNU C version 2.96 adds explicit branch prediction so that 375 * the CPU back-end can hint the processor and also so that 376 * code blocks can be reordered such that the predicted path 377 * sees a more linear flow, thus improving cache behavior, etc. 378 * 379 * The following two macros provide us with a way to utilize this 380 * compiler feature. Use __predict_true() if you expect the expression 381 * to evaluate to true, and __predict_false() if you expect the 382 * expression to evaluate to false. 383 * 384 * A few notes about usage: 385 * 386 * * Generally, __predict_false() error condition checks (unless 387 * you have some _strong_ reason to do otherwise, in which case 388 * document it), and/or __predict_true() `no-error' condition 389 * checks, assuming you want to optimize for the no-error case. 390 * 391 * * Other than that, if you don't know the likelihood of a test 392 * succeeding from empirical or other `hard' evidence, don't 393 * make predictions. 394 * 395 * * These are meant to be used in places that are run `a lot'. 396 * It is wasteful to make predictions in code that is run 397 * seldomly (e.g. at subsystem initialization time) as the 398 * basic block reordering that this affects can often generate 399 * larger code. 400 */ 401 #if __GNUC_PREREQ__(2, 96) 402 #define __predict_true(exp) __builtin_expect((exp), 1) 403 #define __predict_false(exp) __builtin_expect((exp), 0) 404 #else 405 #define __predict_true(exp) (exp) 406 #define __predict_false(exp) (exp) 407 #endif 408 409 #if __GNUC_PREREQ__(4, 0) 410 #define __null_sentinel __attribute__((__sentinel__)) 411 #define __exported __attribute__((__visibility__("default"))) 412 #define __hidden __attribute__((__visibility__("hidden"))) 413 #else 414 #define __null_sentinel 415 #define __exported 416 #define __hidden 417 #endif 418 419 /* 420 * We define this here since <stddef.h>, <sys/queue.h>, and <sys/types.h> 421 * require it. 422 */ 423 #if __GNUC_PREREQ__(4, 1) 424 #define __offsetof(type, field) __builtin_offsetof(type, field) 425 #else 426 #ifndef __cplusplus 427 #define __offsetof(type, field) \ 428 ((__size_t)(__uintptr_t)((const volatile void *)&((type *)0)->field)) 429 #else 430 #define __offsetof(type, field) \ 431 (__offsetof__ (reinterpret_cast <__size_t> \ 432 (&reinterpret_cast <const volatile char &> \ 433 (static_cast<type *> (0)->field)))) 434 #endif 435 #endif 436 #define __rangeof(type, start, end) \ 437 (__offsetof(type, end) - __offsetof(type, start)) 438 439 /* 440 * Given the pointer x to the member m of the struct s, return 441 * a pointer to the containing structure. When using GCC, we first 442 * assign pointer x to a local variable, to check that its type is 443 * compatible with member m. 444 */ 445 #if __GNUC_PREREQ__(3, 1) 446 #define __containerof(x, s, m) ({ \ 447 const volatile __typeof(((s *)0)->m) *__x = (x); \ 448 __DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m));\ 449 }) 450 #else 451 #define __containerof(x, s, m) \ 452 __DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m)) 453 #endif 454 455 /* 456 * Compiler-dependent macros to declare that functions take printf-like 457 * or scanf-like arguments. They are null except for versions of gcc 458 * that are known to support the features properly (old versions of gcc-2 459 * didn't permit keeping the keywords out of the application namespace). 460 */ 461 #if !__GNUC_PREREQ__(2, 7) 462 #define __printflike(fmtarg, firstvararg) 463 #define __scanflike(fmtarg, firstvararg) 464 #define __format_arg(fmtarg) 465 #define __strfmonlike(fmtarg, firstvararg) 466 #define __strftimelike(fmtarg, firstvararg) 467 #else 468 #define __printflike(fmtarg, firstvararg) \ 469 __attribute__((__format__ (__printf__, fmtarg, firstvararg))) 470 #define __scanflike(fmtarg, firstvararg) \ 471 __attribute__((__format__ (__scanf__, fmtarg, firstvararg))) 472 #define __format_arg(fmtarg) __attribute__((__format_arg__ (fmtarg))) 473 #define __strfmonlike(fmtarg, firstvararg) \ 474 __attribute__((__format__ (__strfmon__, fmtarg, firstvararg))) 475 #define __strftimelike(fmtarg, firstvararg) \ 476 __attribute__((__format__ (__strftime__, fmtarg, firstvararg))) 477 #endif 478 479 /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */ 480 #if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \ 481 defined(__GNUC__) 482 #define __printf0like(fmtarg, firstvararg) \ 483 __attribute__((__format__ (__printf0__, fmtarg, firstvararg))) 484 #else 485 #define __printf0like(fmtarg, firstvararg) 486 #endif 487 488 #if defined(__GNUC__) 489 #define __strong_reference(sym,aliassym) \ 490 extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym))) 491 #ifdef __STDC__ 492 #define __weak_reference(sym,alias) \ 493 __asm__(".weak " #alias); \ 494 __asm__(".equ " #alias ", " #sym) 495 #define __warn_references(sym,msg) \ 496 __asm__(".section .gnu.warning." #sym); \ 497 __asm__(".asciz \"" msg "\""); \ 498 __asm__(".previous") 499 #define __sym_compat(sym,impl,verid) \ 500 __asm__(".symver " #impl ", " #sym "@" #verid) 501 #define __sym_default(sym,impl,verid) \ 502 __asm__(".symver " #impl ", " #sym "@@@" #verid) 503 #else 504 #define __weak_reference(sym,alias) \ 505 __asm__(".weak alias"); \ 506 __asm__(".equ alias, sym") 507 #define __warn_references(sym,msg) \ 508 __asm__(".section .gnu.warning.sym"); \ 509 __asm__(".asciz \"msg\""); \ 510 __asm__(".previous") 511 #define __sym_compat(sym,impl,verid) \ 512 __asm__(".symver impl, sym@verid") 513 #define __sym_default(impl,sym,verid) \ 514 __asm__(".symver impl, sym@@@verid") 515 #endif /* __STDC__ */ 516 #endif /* __GNUC__ */ 517 518 #define __GLOBL(sym) __asm__(".globl " __XSTRING(sym)) 519 #define __WEAK(sym) __asm__(".weak " __XSTRING(sym)) 520 521 #if defined(__GNUC__) 522 #define __IDSTRING(name,string) __asm__(".ident\t\"" string "\"") 523 #else 524 /* 525 * The following definition might not work well if used in header files, 526 * but it should be better than nothing. If you want a "do nothing" 527 * version, then it should generate some harmless declaration, such as: 528 * #define __IDSTRING(name,string) struct __hack 529 */ 530 #define __IDSTRING(name,string) static const char name[] __unused = string 531 #endif 532 533 /* 534 * Embed the rcs id of a source file in the resulting library. Note that in 535 * more recent ELF binutils, we use .ident allowing the ID to be stripped. 536 * Usage: 537 */ 538 #ifndef __FBSDID 539 #if !defined(STRIP_FBSDID) 540 #define __FBSDID(s) __IDSTRING(__CONCAT(__rcsid_,__LINE__),s) 541 #else 542 #define __FBSDID(s) struct __hack 543 #endif 544 #endif 545 546 #ifndef __RCSID 547 #ifndef NO__RCSID 548 #define __RCSID(s) __IDSTRING(__CONCAT(__rcsid_,__LINE__),s) 549 #else 550 #define __RCSID(s) struct __hack 551 #endif 552 #endif 553 554 #ifndef __RCSID_SOURCE 555 #ifndef NO__RCSID_SOURCE 556 #define __RCSID_SOURCE(s) __IDSTRING(__CONCAT(__rcsid_source_,__LINE__),s) 557 #else 558 #define __RCSID_SOURCE(s) struct __hack 559 #endif 560 #endif 561 562 #ifndef __SCCSID 563 #ifndef NO__SCCSID 564 #define __SCCSID(s) __IDSTRING(__CONCAT(__sccsid_,__LINE__),s) 565 #else 566 #define __SCCSID(s) struct __hack 567 #endif 568 #endif 569 570 #ifndef __COPYRIGHT 571 #ifndef NO__COPYRIGHT 572 #define __COPYRIGHT(s) __IDSTRING(__CONCAT(__copyright_,__LINE__),s) 573 #else 574 #define __COPYRIGHT(s) struct __hack 575 #endif 576 #endif 577 578 #ifndef __DECONST 579 #define __DECONST(type, var) ((type)(__uintptr_t)(const void *)(var)) 580 #endif 581 582 #ifndef __DEVOLATILE 583 #define __DEVOLATILE(type, var) ((type)(__uintptr_t)(volatile void *)(var)) 584 #endif 585 586 #ifndef __DEQUALIFY 587 #define __DEQUALIFY(type, var) ((type)(__uintptr_t)(const volatile void *)(var)) 588 #endif 589 590 /*- 591 * The following definitions are an extension of the behavior originally 592 * implemented in <sys/_posix.h>, but with a different level of granularity. 593 * POSIX.1 requires that the macros we test be defined before any standard 594 * header file is included. 595 * 596 * Here's a quick run-down of the versions (and some informal names) 597 * defined(_POSIX_SOURCE) 1003.1-1988 598 * encoded as 198808 below 599 * _POSIX_C_SOURCE == 1 1003.1-1990 600 * encoded as 199009 below 601 * _POSIX_C_SOURCE == 2 1003.2-1992 C Language Binding Option 602 * encoded as 199209 below 603 * _POSIX_C_SOURCE == 199309 1003.1b-1993 604 * (1003.1 Issue 4, Single Unix Spec v1, Unix 93) 605 * _POSIX_C_SOURCE == 199506 1003.1c-1995, 1003.1i-1995, 606 * and the omnibus ISO/IEC 9945-1: 1996 607 * (1003.1 Issue 5, Single Unix Spec v2, Unix 95) 608 * _POSIX_C_SOURCE == 200112 1003.1-2001 (1003.1 Issue 6, Unix 03) 609 * _POSIX_C_SOURCE == 200809 1003.1-2008 (1003.1 Issue 7) 610 * IEEE Std 1003.1-2017 (Rev of 1003.1-2008) is 611 * 1003.1-2008 with two TCs applied with 612 * _POSIX_C_SOURCE=200809 and _XOPEN_SOURCE=700 613 * 614 * In addition, the X/Open Portability Guide, which is now the Single UNIX 615 * Specification, defines a feature-test macro which indicates the version of 616 * that specification, and which subsumes _POSIX_C_SOURCE. 617 * 618 * Our macros begin with two underscores to avoid namespace screwage. 619 */ 620 621 /* Deal with IEEE Std. 1003.1-1990, in which _POSIX_C_SOURCE == 1. */ 622 #if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 1 623 #undef _POSIX_C_SOURCE /* Probably illegal, but beyond caring now. */ 624 #define _POSIX_C_SOURCE 199009 625 #endif 626 627 /* Deal with IEEE Std. 1003.2-1992, in which _POSIX_C_SOURCE == 2. */ 628 #if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 2 629 #undef _POSIX_C_SOURCE 630 #define _POSIX_C_SOURCE 199209 631 #endif 632 633 /* Deal with various X/Open Portability Guides and Single UNIX Spec. */ 634 #ifdef _XOPEN_SOURCE 635 #if _XOPEN_SOURCE - 0 >= 700 636 #define __XSI_VISIBLE 700 637 #undef _POSIX_C_SOURCE 638 #define _POSIX_C_SOURCE 200809 639 #elif _XOPEN_SOURCE - 0 >= 600 640 #define __XSI_VISIBLE 600 641 #undef _POSIX_C_SOURCE 642 #define _POSIX_C_SOURCE 200112 643 #elif _XOPEN_SOURCE - 0 >= 500 644 #define __XSI_VISIBLE 500 645 #undef _POSIX_C_SOURCE 646 #define _POSIX_C_SOURCE 199506 647 #endif 648 #endif 649 650 /* 651 * Deal with all versions of POSIX. The ordering relative to the tests above is 652 * important. 653 */ 654 #if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE) 655 #define _POSIX_C_SOURCE 198808 656 #endif 657 #ifdef _POSIX_C_SOURCE 658 #if _POSIX_C_SOURCE >= 200809 659 #define __POSIX_VISIBLE 200809 660 #define __ISO_C_VISIBLE 1999 661 #elif _POSIX_C_SOURCE >= 200112 662 #define __POSIX_VISIBLE 200112 663 #define __ISO_C_VISIBLE 1999 664 #elif _POSIX_C_SOURCE >= 199506 665 #define __POSIX_VISIBLE 199506 666 #define __ISO_C_VISIBLE 1990 667 #elif _POSIX_C_SOURCE >= 199309 668 #define __POSIX_VISIBLE 199309 669 #define __ISO_C_VISIBLE 1990 670 #elif _POSIX_C_SOURCE >= 199209 671 #define __POSIX_VISIBLE 199209 672 #define __ISO_C_VISIBLE 1990 673 #elif _POSIX_C_SOURCE >= 199009 674 #define __POSIX_VISIBLE 199009 675 #define __ISO_C_VISIBLE 1990 676 #else 677 #define __POSIX_VISIBLE 198808 678 #define __ISO_C_VISIBLE 0 679 #endif /* _POSIX_C_SOURCE */ 680 /* 681 * Both glibc and OpenBSD enable c11 features when _ISOC11_SOURCE is defined, or 682 * when compiling with -stdc=c11. A strict reading of the standard would suggest 683 * doing it only for the former. However, a strict reading also requires C99 684 * mode only, so building with C11 is already undefined. Follow glibc's and 685 * OpenBSD's lead for this non-standard configuration for maximum compatibility. 686 */ 687 #if _ISOC11_SOURCE || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) 688 #undef __ISO_C_VISIBLE 689 #define __ISO_C_VISIBLE 2011 690 #endif 691 #else 692 /*- 693 * Deal with _ANSI_SOURCE: 694 * If it is defined, and no other compilation environment is explicitly 695 * requested, then define our internal feature-test macros to zero. This 696 * makes no difference to the preprocessor (undefined symbols in preprocessing 697 * expressions are defined to have value zero), but makes it more convenient for 698 * a test program to print out the values. 699 * 700 * If a program mistakenly defines _ANSI_SOURCE and some other macro such as 701 * _POSIX_C_SOURCE, we will assume that it wants the broader compilation 702 * environment (and in fact we will never get here). 703 */ 704 #if defined(_ANSI_SOURCE) /* Hide almost everything. */ 705 #define __POSIX_VISIBLE 0 706 #define __XSI_VISIBLE 0 707 #define __BSD_VISIBLE 0 708 #define __ISO_C_VISIBLE 1990 709 #define __EXT1_VISIBLE 0 710 #elif defined(_C99_SOURCE) /* Localism to specify strict C99 env. */ 711 #define __POSIX_VISIBLE 0 712 #define __XSI_VISIBLE 0 713 #define __BSD_VISIBLE 0 714 #define __ISO_C_VISIBLE 1999 715 #define __EXT1_VISIBLE 0 716 #elif defined(_C11_SOURCE) /* Localism to specify strict C11 env. */ 717 #define __POSIX_VISIBLE 0 718 #define __XSI_VISIBLE 0 719 #define __BSD_VISIBLE 0 720 #define __ISO_C_VISIBLE 2011 721 #define __EXT1_VISIBLE 0 722 #else /* Default environment: show everything. */ 723 #define __POSIX_VISIBLE 200809 724 #define __XSI_VISIBLE 700 725 #define __BSD_VISIBLE 1 726 #define __ISO_C_VISIBLE 2011 727 #define __EXT1_VISIBLE 1 728 #endif 729 #endif 730 731 /* User override __EXT1_VISIBLE */ 732 #if defined(__STDC_WANT_LIB_EXT1__) 733 #undef __EXT1_VISIBLE 734 #if __STDC_WANT_LIB_EXT1__ 735 #define __EXT1_VISIBLE 1 736 #else 737 #define __EXT1_VISIBLE 0 738 #endif 739 #endif /* __STDC_WANT_LIB_EXT1__ */ 740 741 /* 742 * Old versions of GCC use non-standard ARM arch symbols; acle-compat.h 743 * translates them to __ARM_ARCH and the modern feature symbols defined by ARM. 744 */ 745 #if defined(__arm__) && !defined(__ARM_ARCH) 746 #include <machine/acle-compat.h> 747 #endif 748 749 /* 750 * Nullability qualifiers: currently only supported by Clang. 751 */ 752 #if !(defined(__clang__) && __has_feature(nullability)) 753 #define _Nonnull 754 #define _Nullable 755 #define _Null_unspecified 756 #define __NULLABILITY_PRAGMA_PUSH 757 #define __NULLABILITY_PRAGMA_POP 758 #else 759 #define __NULLABILITY_PRAGMA_PUSH _Pragma("clang diagnostic push") \ 760 _Pragma("clang diagnostic ignored \"-Wnullability-completeness\"") 761 #define __NULLABILITY_PRAGMA_POP _Pragma("clang diagnostic pop") 762 #endif 763 764 /* 765 * Type Safety Checking 766 * 767 * Clang provides additional attributes to enable checking type safety 768 * properties that cannot be enforced by the C type system. 769 */ 770 771 #if __has_attribute(__argument_with_type_tag__) && \ 772 __has_attribute(__type_tag_for_datatype__) 773 #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx) \ 774 __attribute__((__argument_with_type_tag__(arg_kind, arg_idx, type_tag_idx))) 775 #define __datatype_type_tag(kind, type) \ 776 __attribute__((__type_tag_for_datatype__(kind, type))) 777 #else 778 #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx) 779 #define __datatype_type_tag(kind, type) 780 #endif 781 782 /* 783 * Lock annotations. 784 * 785 * Clang provides support for doing basic thread-safety tests at 786 * compile-time, by marking which locks will/should be held when 787 * entering/leaving a functions. 788 * 789 * Furthermore, it is also possible to annotate variables and structure 790 * members to enforce that they are only accessed when certain locks are 791 * held. 792 */ 793 794 #if __has_extension(c_thread_safety_attributes) 795 #define __lock_annotate(x) __attribute__((x)) 796 #else 797 #define __lock_annotate(x) 798 #endif 799 800 /* Structure implements a lock. */ 801 #define __lockable __lock_annotate(lockable) 802 803 /* Function acquires an exclusive or shared lock. */ 804 #define __locks_exclusive(...) \ 805 __lock_annotate(exclusive_lock_function(__VA_ARGS__)) 806 #define __locks_shared(...) \ 807 __lock_annotate(shared_lock_function(__VA_ARGS__)) 808 809 /* Function attempts to acquire an exclusive or shared lock. */ 810 #define __trylocks_exclusive(...) \ 811 __lock_annotate(exclusive_trylock_function(__VA_ARGS__)) 812 #define __trylocks_shared(...) \ 813 __lock_annotate(shared_trylock_function(__VA_ARGS__)) 814 815 /* Function releases a lock. */ 816 #define __unlocks(...) __lock_annotate(unlock_function(__VA_ARGS__)) 817 818 /* Function asserts that an exclusive or shared lock is held. */ 819 #define __asserts_exclusive(...) \ 820 __lock_annotate(assert_exclusive_lock(__VA_ARGS__)) 821 #define __asserts_shared(...) \ 822 __lock_annotate(assert_shared_lock(__VA_ARGS__)) 823 824 /* Function requires that an exclusive or shared lock is or is not held. */ 825 #define __requires_exclusive(...) \ 826 __lock_annotate(exclusive_locks_required(__VA_ARGS__)) 827 #define __requires_shared(...) \ 828 __lock_annotate(shared_locks_required(__VA_ARGS__)) 829 #define __requires_unlocked(...) \ 830 __lock_annotate(locks_excluded(__VA_ARGS__)) 831 832 /* Function should not be analyzed. */ 833 #define __no_lock_analysis __lock_annotate(no_thread_safety_analysis) 834 835 /* 836 * Function or variable should not be sanitized, e.g., by AddressSanitizer. 837 * GCC has the nosanitize attribute, but as a function attribute only, and 838 * warns on use as a variable attribute. 839 */ 840 #if __has_attribute(no_sanitize) && defined(__clang__) 841 #ifdef _KERNEL 842 #define __nosanitizeaddress __attribute__((no_sanitize("kernel-address"))) 843 #define __nosanitizememory __attribute__((no_sanitize("kernel-memory"))) 844 #else 845 #define __nosanitizeaddress __attribute__((no_sanitize("address"))) 846 #define __nosanitizememory __attribute__((no_sanitize("memory"))) 847 #endif 848 #define __nosanitizethread __attribute__((no_sanitize("thread"))) 849 #else 850 #define __nosanitizeaddress 851 #define __nosanitizememory 852 #define __nosanitizethread 853 #endif 854 855 /* 856 * Make it possible to opt out of stack smashing protection. 857 */ 858 #if __has_attribute(no_stack_protector) 859 #define __nostackprotector __attribute__((no_stack_protector)) 860 #else 861 #define __nostackprotector \ 862 __attribute__((__optimize__("-fno-stack-protector"))) 863 #endif 864 865 /* Guard variables and structure members by lock. */ 866 #define __guarded_by(x) __lock_annotate(guarded_by(x)) 867 #define __pt_guarded_by(x) __lock_annotate(pt_guarded_by(x)) 868 869 /* Alignment builtins for better type checking and improved code generation. */ 870 /* Provide fallback versions for other compilers (GCC/Clang < 10): */ 871 #if !__has_builtin(__builtin_is_aligned) 872 #define __builtin_is_aligned(x, align) \ 873 (((__uintptr_t)x & ((align) - 1)) == 0) 874 #endif 875 #if !__has_builtin(__builtin_align_up) 876 #define __builtin_align_up(x, align) \ 877 ((__typeof__(x))(((__uintptr_t)(x)+((align)-1))&(~((align)-1)))) 878 #endif 879 #if !__has_builtin(__builtin_align_down) 880 #define __builtin_align_down(x, align) \ 881 ((__typeof__(x))((x)&(~((align)-1)))) 882 #endif 883 884 #define __align_up(x, y) __builtin_align_up(x, y) 885 #define __align_down(x, y) __builtin_align_down(x, y) 886 #define __is_aligned(x, y) __builtin_is_aligned(x, y) 887 888 #endif /* !_SYS_CDEFS_H_ */ 889