1 /* libc/sys/linux/sys/cdefs.h - Helper macros for K&R vs. ANSI C compat. */ 2 3 /* Written 2000 by Werner Almesberger */ 4 5 /*- 6 * SPDX-License-Identifier: BSD-3-Clause 7 * 8 * Copyright (c) 1991, 1993 9 * The Regents of the University of California. All rights reserved. 10 * 11 * This code is derived from software contributed to Berkeley by 12 * Berkeley Software Design, Inc. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)cdefs.h 8.8 (Berkeley) 1/9/95 39 * $FreeBSD$ 40 */ 41 42 #ifndef _SYS_CDEFS_H_ 43 #define _SYS_CDEFS_H_ 44 45 #include <machine/_default_types.h> 46 #include <sys/features.h> 47 #include <stddef.h> 48 49 #define __PMT(args) args 50 #define __DOTS , ... 51 #define __THROW 52 53 #ifdef __GNUC__ 54 # define __ASMNAME(cname) __XSTRING (__USER_LABEL_PREFIX__) cname 55 #endif 56 57 #define __ptr_t void * 58 #define __long_double_t long double 59 60 #define __attribute_malloc__ 61 #define __attribute_pure__ 62 #define __attribute_format_strfmon__(a,b) 63 #define __flexarr [0] 64 65 #ifndef __BOUNDED_POINTERS__ 66 # define __bounded /* nothing */ 67 # define __unbounded /* nothing */ 68 # define __ptrvalue /* nothing */ 69 #endif 70 71 /* 72 * Testing against Clang-specific extensions. 73 */ 74 #ifndef __has_attribute 75 #define __has_attribute(x) 0 76 #endif 77 #ifndef __has_extension 78 #define __has_extension __has_feature 79 #endif 80 #ifndef __has_feature 81 #define __has_feature(x) 0 82 #endif 83 #ifndef __has_include 84 #define __has_include(x) 0 85 #endif 86 #ifndef __has_builtin 87 #define __has_builtin(x) 0 88 #endif 89 90 #if defined(__cplusplus) 91 #define __BEGIN_DECLS extern "C" { 92 #define __END_DECLS } 93 #else 94 #define __BEGIN_DECLS 95 #define __END_DECLS 96 #endif 97 98 /** 99 * Not all compilers offer __builtin_expect (e.g. CompCert does 100 * not have it). In that case, transparently replace all 101 * occurences of that builtin with just the condition: 102 */ 103 #ifndef _HAVE_BUILTIN_EXPECT 104 #define __builtin_expect(cond, exp) (cond) 105 #endif 106 107 /* 108 * This code has been put in place to help reduce the addition of 109 * compiler specific defines in FreeBSD code. It helps to aid in 110 * having a compiler-agnostic source tree. 111 */ 112 113 #if defined(__GNUC__) 114 115 #if __GNUC__ >= 3 116 #define __GNUCLIKE_ASM 3 117 #define __GNUCLIKE_MATH_BUILTIN_CONSTANTS 118 #else 119 #define __GNUCLIKE_ASM 2 120 #endif 121 #define __GNUCLIKE___TYPEOF 1 122 #define __GNUCLIKE___SECTION 1 123 124 #define __GNUCLIKE_CTOR_SECTION_HANDLING 1 125 126 #define __GNUCLIKE_BUILTIN_CONSTANT_P 1 127 128 #if (__GNUC_MINOR__ > 95 || __GNUC__ >= 3) 129 #define __GNUCLIKE_BUILTIN_VARARGS 1 130 #define __GNUCLIKE_BUILTIN_STDARG 1 131 #define __GNUCLIKE_BUILTIN_VAALIST 1 132 #endif 133 134 #define __GNUC_VA_LIST_COMPATIBILITY 1 135 136 /* 137 * Compiler memory barriers, specific to gcc and clang. 138 */ 139 #define __compiler_membar() __asm __volatile(" " : : : "memory") 140 141 #define __GNUCLIKE_BUILTIN_NEXT_ARG 1 142 #define __GNUCLIKE_MATH_BUILTIN_RELOPS 143 144 #define __GNUCLIKE_BUILTIN_MEMCPY 1 145 146 /* XXX: if __GNUC__ >= 2: not tested everywhere originally, where replaced */ 147 #define __CC_SUPPORTS_INLINE 1 148 #define __CC_SUPPORTS___INLINE 1 149 #define __CC_SUPPORTS___INLINE__ 1 150 151 #define __CC_SUPPORTS___FUNC__ 1 152 #define __CC_SUPPORTS_WARNING 1 153 154 #define __CC_SUPPORTS_VARADIC_XXX 1 /* see varargs.h */ 155 156 #define __CC_SUPPORTS_DYNAMIC_ARRAY_INIT 1 157 158 #endif /* __GNUC__ */ 159 160 /* 161 * The __CONCAT macro is used to concatenate parts of symbol names, e.g. 162 * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo. 163 * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI 164 * mode -- there must be no spaces between its arguments, and for nested 165 * __CONCAT's, all the __CONCAT's must be at the left. __CONCAT can also 166 * concatenate double-quoted strings produced by the __STRING macro, but 167 * this only works with ANSI C. 168 * 169 * __XSTRING is like __STRING, but it expands any macros in its argument 170 * first. It is only available with ANSI C. 171 */ 172 #if defined(__STDC__) || defined(__cplusplus) 173 #define __P(protos) protos /* full-blown ANSI C */ 174 #define __CONCAT1(x,y) x ## y 175 #define __CONCAT(x,y) __CONCAT1(x,y) 176 #define __STRING(x) #x /* stringify without expanding x */ 177 #define __XSTRING(x) __STRING(x) /* expand x, then stringify */ 178 179 #define __const const /* define reserved names to standard */ 180 #define __signed signed 181 #define __volatile volatile 182 #if defined(__cplusplus) 183 #define __inline inline /* convert to C++ keyword */ 184 #else 185 #if !(defined(__CC_SUPPORTS___INLINE)) 186 #define __inline /* delete GCC keyword */ 187 #endif /* ! __CC_SUPPORTS___INLINE */ 188 #endif /* !__cplusplus */ 189 190 #else /* !(__STDC__ || __cplusplus) */ 191 #define __P(protos) () /* traditional C preprocessor */ 192 #define __CONCAT(x,y) x/**/y 193 #define __STRING(x) "x" 194 195 #if !defined(__CC_SUPPORTS___INLINE) 196 #define __const /* delete pseudo-ANSI C keywords */ 197 #define __inline 198 #define __signed 199 #define __volatile 200 /* 201 * In non-ANSI C environments, new programs will want ANSI-only C keywords 202 * deleted from the program and old programs will want them left alone. 203 * When using a compiler other than gcc, programs using the ANSI C keywords 204 * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS. 205 * When using "gcc -traditional", we assume that this is the intent; if 206 * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone. 207 */ 208 #ifndef NO_ANSI_KEYWORDS 209 #define const /* delete ANSI C keywords */ 210 #define inline 211 #define signed 212 #define volatile 213 #endif /* !NO_ANSI_KEYWORDS */ 214 #endif /* !__CC_SUPPORTS___INLINE */ 215 #endif /* !(__STDC__ || __cplusplus) */ 216 217 /* 218 * Compiler-dependent macros to help declare dead (non-returning) and 219 * pure (no side effects) functions, and unused variables. They are 220 * null except for versions of gcc that are known to support the features 221 * properly (old versions of gcc-2 supported the dead and pure features 222 * in a different (wrong) way). If we do not provide an implementation 223 * for a given compiler, let the compile fail if it is told to use 224 * a feature that we cannot live without. 225 */ 226 #define __weak_symbol __attribute__((__weak__)) 227 #if !__GNUC_PREREQ__(2, 5) 228 #define __dead2 229 #define __pure2 230 #define __unused 231 #endif 232 #if __GNUC__ == 2 && __GNUC_MINOR__ >= 5 && __GNUC_MINOR__ < 7 233 #define __dead2 __attribute__((__noreturn__)) 234 #define __pure2 __attribute__((__const__)) 235 #define __unused 236 /* XXX Find out what to do for __packed, __aligned and __section */ 237 #endif 238 #if __GNUC_PREREQ__(2, 7) 239 #define __dead2 __attribute__((__noreturn__)) 240 #define __pure2 __attribute__((__const__)) 241 #define __unused __attribute__((__unused__)) 242 #define __used __attribute__((__used__)) 243 #define __packed __attribute__((__packed__)) 244 #define __aligned(x) __attribute__((__aligned__(x))) 245 #define __section(x) __attribute__((__section__(x))) 246 #endif 247 248 #ifdef _HAVE_ALLOC_SIZE 249 #define __alloc_size(x) __attribute__((__alloc_size__(x))) 250 #define __alloc_size2(n, x) __attribute__((__alloc_size__(n, x))) 251 #else 252 #define __alloc_size(x) 253 #define __alloc_size2(n, x) 254 #endif 255 #if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__) 256 #define __alloc_align(x) __attribute__((__alloc_align__(x))) 257 #else 258 #define __alloc_align(x) 259 #endif 260 261 #if !__GNUC_PREREQ__(2, 95) 262 #define __alignof(x) __offsetof(struct { char __a; x __b; }, __b) 263 #endif 264 265 #if __GNUC_PREREQ__(4,5) || defined(__clang__) 266 #define __picolibc_deprecated(m) __attribute__((__deprecated__(m))) 267 #else 268 #define __picolibc_deprecated(m) _ATTRIBUTE(__deprecated__) 269 #endif 270 271 /* 272 * Keywords added in C11. 273 */ 274 275 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L 276 277 #if !__has_extension(c_alignas) 278 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \ 279 __has_extension(cxx_alignas) 280 #define _Alignas(x) alignas(x) 281 #else 282 /* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */ 283 #define _Alignas(x) __aligned(x) 284 #endif 285 #endif 286 287 #if defined(__cplusplus) && __cplusplus >= 201103L 288 #define _Alignof(x) alignof(x) 289 #else 290 #define _Alignof(x) __alignof(x) 291 #endif 292 293 #if !defined(__cplusplus) && !__has_extension(c_atomic) && \ 294 !__has_extension(cxx_atomic) && !__GNUC_PREREQ__(4, 7) 295 /* 296 * No native support for _Atomic(). Place object in structure to prevent 297 * most forms of direct non-atomic access. 298 */ 299 #define _Atomic(T) struct { T volatile __val; } 300 #endif 301 302 #if defined(__cplusplus) && __cplusplus >= 201103L 303 #define _Noreturn [[noreturn]] 304 #else 305 #define _Noreturn __dead2 306 #endif 307 308 #if !__has_extension(c_static_assert) 309 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \ 310 __has_extension(cxx_static_assert) 311 #define _Static_assert(x, y) static_assert(x, y) 312 #elif __GNUC_PREREQ__(4,6) && !defined(__cplusplus) 313 /* Nothing, gcc 4.6 and higher has _Static_assert built-in */ 314 #elif defined(__COUNTER__) 315 #define _Static_assert(x, y) __Static_assert(x, __COUNTER__) 316 #define __Static_assert(x, y) ___Static_assert(x, y) 317 #define ___Static_assert(x, y) typedef char __assert_ ## y[(x) ? 1 : -1] \ 318 __unused 319 #else 320 #define _Static_assert(x, y) struct __hack 321 #endif 322 #endif 323 324 #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */ 325 326 /* 327 * Emulation of C11 _Generic(). Unlike the previously defined C11 328 * keywords, it is not possible to implement this using exactly the same 329 * syntax. Therefore implement something similar under the name 330 * __generic(). Unlike _Generic(), this macro can only distinguish 331 * between a single type, so it requires nested invocations to 332 * distinguish multiple cases. 333 */ 334 335 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \ 336 __has_extension(c_generic_selections) 337 #define __generic(expr, t, yes, no) \ 338 _Generic(expr, t: yes, default: no) 339 #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus) 340 #define __generic(expr, t, yes, no) \ 341 __builtin_choose_expr( \ 342 __builtin_types_compatible_p(__typeof(expr), t), yes, no) 343 #endif 344 345 /* 346 * C99 Static array indices in function parameter declarations. Syntax such as: 347 * void bar(int myArray[static 10]); 348 * is allowed in C99 but not in C++. Define __min_size appropriately so 349 * headers using it can be compiled in either language. Use like this: 350 * void bar(int myArray[__min_size(10)]); 351 */ 352 #if !defined(__cplusplus) && \ 353 (defined(__clang__) || __GNUC_PREREQ__(4, 6)) && \ 354 (!defined(__STDC_VERSION__) || (__STDC_VERSION__ >= 199901)) 355 #define __min_size(x) static (x) 356 #else 357 #define __min_size(x) (x) 358 #endif 359 360 #if __GNUC_PREREQ__(2, 96) 361 # if __GNUC_PREREQ__(11, 0) 362 # define __malloc_like_with_free(_f,_a) __attribute__((__malloc__, __malloc__(_f,_a))) 363 # else 364 # define __malloc_like_with_free(_f,_a) __attribute__((__malloc__)) 365 # endif 366 # define __pure __attribute__((__pure__)) 367 #else 368 #define __malloc_like_with_free(free,free_arg) 369 #define __pure 370 #endif 371 372 #define __malloc_like __malloc_like_with_free(free, 1) 373 374 #ifndef __always_inline 375 #if __GNUC_PREREQ__(3, 1) 376 #define __always_inline __inline__ __attribute__((__always_inline__)) 377 #else 378 #define __always_inline 379 #endif 380 #endif 381 382 #ifndef __noinline 383 #if __GNUC_PREREQ__(3, 1) 384 #define __noinline __attribute__ ((__noinline__)) 385 #else 386 #define __noinline 387 #endif 388 #endif 389 390 #if defined(__clang__) && defined(__nonnull) 391 /* Clang has a builtin macro __nonnull for the _Nonnull qualifier */ 392 #undef __nonnull 393 #endif 394 #if __GNUC_PREREQ__(3, 3) 395 #define __nonnull(x) __attribute__((__nonnull__ x)) 396 #define __nonnull_all __attribute__((__nonnull__)) 397 #else 398 #define __nonnull(x) 399 #define __nonnull_all 400 #endif 401 402 #if __GNUC_PREREQ__(3, 4) 403 #define __fastcall __attribute__((__fastcall__)) 404 #define __result_use_check __attribute__((__warn_unused_result__)) 405 #else 406 #define __fastcall 407 #define __result_use_check 408 #endif 409 410 #if __GNUC_PREREQ__(4, 1) 411 #define __returns_twice __attribute__((__returns_twice__)) 412 #else 413 #define __returns_twice 414 #endif 415 416 #if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable) 417 #define __unreachable() __builtin_unreachable() 418 #else 419 #define __unreachable() ((void)0) 420 #endif 421 422 /* XXX: should use `#if __STDC_VERSION__ < 199901'. */ 423 #if !__GNUC_PREREQ__(2, 7) && !defined(__COMPCERT__) 424 #define __func__ NULL 425 #endif 426 427 /* 428 * GCC 2.95 provides `__restrict' as an extension to C90 to support the 429 * C99-specific `restrict' type qualifier. We happen to use `__restrict' as 430 * a way to define the `restrict' type qualifier without disturbing older 431 * software that is unaware of C99 keywords. 432 */ 433 #if !(__GNUC__ == 2 && __GNUC_MINOR__ == 95) 434 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901 435 #define __restrict 436 #else 437 #define __restrict restrict 438 #endif 439 #endif 440 441 /* 442 * GNU C version 2.96 adds explicit branch prediction so that 443 * the CPU back-end can hint the processor and also so that 444 * code blocks can be reordered such that the predicted path 445 * sees a more linear flow, thus improving cache behavior, etc. 446 * 447 * The following two macros provide us with a way to utilize this 448 * compiler feature. Use __predict_true() if you expect the expression 449 * to evaluate to true, and __predict_false() if you expect the 450 * expression to evaluate to false. 451 * 452 * A few notes about usage: 453 * 454 * * Generally, __predict_false() error condition checks (unless 455 * you have some _strong_ reason to do otherwise, in which case 456 * document it), and/or __predict_true() `no-error' condition 457 * checks, assuming you want to optimize for the no-error case. 458 * 459 * * Other than that, if you don't know the likelihood of a test 460 * succeeding from empirical or other `hard' evidence, don't 461 * make predictions. 462 * 463 * * These are meant to be used in places that are run `a lot'. 464 * It is wasteful to make predictions in code that is run 465 * seldomly (e.g. at subsystem initialization time) as the 466 * basic block reordering that this affects can often generate 467 * larger code. 468 */ 469 #if __GNUC_PREREQ__(2, 96) 470 #define __predict_true(exp) __builtin_expect((exp), 1) 471 #define __predict_false(exp) __builtin_expect((exp), 0) 472 #else 473 #define __predict_true(exp) (exp) 474 #define __predict_false(exp) (exp) 475 #endif 476 477 #if __GNUC_PREREQ__(4, 0) 478 #define __null_sentinel __attribute__((__sentinel__)) 479 #define __exported __attribute__((__visibility__("default"))) 480 /* Only default visibility is supported on PE/COFF targets. */ 481 #ifndef __CYGWIN__ 482 #define __hidden __attribute__((__visibility__("hidden"))) 483 #else 484 #define __hidden 485 #endif 486 #else 487 #define __null_sentinel 488 #define __exported 489 #define __hidden 490 #endif 491 492 #define __offsetof(type, field) offsetof(type, field) 493 #define __rangeof(type, start, end) \ 494 (__offsetof(type, end) - __offsetof(type, start)) 495 496 /* 497 * Given the pointer x to the member m of the struct s, return 498 * a pointer to the containing structure. When using GCC, we first 499 * assign pointer x to a local variable, to check that its type is 500 * compatible with member m. 501 */ 502 #if __GNUC_PREREQ__(3, 1) 503 #define __containerof(x, s, m) ({ \ 504 const volatile __typeof(((s *)0)->m) *__x = (x); \ 505 __DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m));\ 506 }) 507 #else 508 #define __containerof(x, s, m) \ 509 __DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m)) 510 #endif 511 512 /* 513 * Compiler-dependent macros to declare that functions take printf-like 514 * or scanf-like arguments. They are null except for versions of gcc 515 * that are known to support the features properly (old versions of gcc-2 516 * didn't permit keeping the keywords out of the application namespace). 517 */ 518 #if !__GNUC_PREREQ__(2, 7) 519 #define __printflike(fmtarg, firstvararg) 520 #define __scanflike(fmtarg, firstvararg) 521 #define __format_arg(fmtarg) 522 #define __strfmonlike(fmtarg, firstvararg) 523 #define __strftimelike(fmtarg, firstvararg) 524 #else 525 #define __printflike(fmtarg, firstvararg) \ 526 __attribute__((__format__ (__printf__, fmtarg, firstvararg))) 527 #define __scanflike(fmtarg, firstvararg) \ 528 __attribute__((__format__ (__scanf__, fmtarg, firstvararg))) 529 #define __format_arg(fmtarg) __attribute__((__format_arg__ (fmtarg))) 530 #define __strfmonlike(fmtarg, firstvararg) \ 531 __attribute__((__format__ (__strfmon__, fmtarg, firstvararg))) 532 #define __strftimelike(fmtarg, firstvararg) \ 533 __attribute__((__format__ (__strftime__, fmtarg, firstvararg))) 534 #endif 535 536 /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */ 537 #if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \ 538 defined(__GNUC__) 539 #define __printf0like(fmtarg, firstvararg) \ 540 __attribute__((__format__ (__printf0__, fmtarg, firstvararg))) 541 #else 542 #define __printf0like(fmtarg, firstvararg) 543 #endif 544 545 #if defined(_HAVE_ALIAS_ATTRIBUTE) 546 #define __strong_reference(sym,aliassym) \ 547 extern __typeof (sym) aliassym __attribute__ ((__alias__ (__STRING(sym)))) 548 #endif 549 550 #if defined(_HAVE_WEAK_ATTRIBUTE) && defined(_HAVE_ALIAS_ATTRIBUTE) 551 #define __weak_reference(sym,aliassym) \ 552 extern __typeof (sym) aliassym __attribute__ ((__weak__, __alias__ (__STRING(sym)))) 553 #endif 554 555 /* 556 Taken from glibc: 557 Add the compiler optimization to inhibit loop transformation to library 558 calls. This is used to avoid recursive calls in memset and memmove 559 default implementations. 560 */ 561 #if defined(_HAVE_CC_INHIBIT_LOOP_TO_LIBCALL) 562 # define __inhibit_loop_to_libcall \ 563 __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns"))) 564 #elif defined(_HAVE_NO_BUILTIN_ATTRIBUTE) 565 # define __inhibit_loop_to_libcall \ 566 __attribute__((no_builtin)) 567 #else 568 # define __inhibit_loop_to_libcall 569 #endif 570 571 /* 572 * Tell optimizer to not add new builtin calls when optimizing a 573 * function body. 574 */ 575 #if defined(_HAVE_NO_BUILTIN_ATTRIBUTE) 576 # define __inhibit_new_builtin_calls \ 577 __attribute__((no_builtin)) 578 #else 579 #define __inhibit_new_builtin_calls 580 #endif 581 582 #if defined(__GNUC__) 583 #ifndef __weak_reference 584 #ifdef __ELF__ 585 #ifdef __STDC__ 586 #define __weak_reference(sym,alias) \ 587 __asm__(".weak " #alias); \ 588 __asm__(".equ " #alias ", " #sym) 589 #else 590 #define __weak_reference(sym,alias) \ 591 __asm__(".weak alias"); \ 592 __asm__(".equ alias, sym") 593 #endif 594 #elif __clang__ 595 #ifdef __MACH__ 596 /* Macos prefixes all C symbols with an underscore, this needs to be done manually in asm */ 597 598 /* So far I have not been able to create on Macos an exported symbol that itself 599 * is weak but aliases a strong symbol. A workaround is to make the original 600 * symbol weak and the alias symbol will automatically become weak too. */ 601 /* Hint: use `nm -m obj.o` to check the symbols weak/strong on Mac */ 602 #define __weak_reference(sym,alias) \ 603 __asm__(".weak_definition _" #sym); \ 604 __asm__(".globl _" #alias); \ 605 __asm__(".set _" #alias ", _" #sym) 606 #elif defined(__STDC__) 607 #define __weak_reference(sym,alias) \ 608 __asm__(".weak_reference " #alias); \ 609 __asm__(".globl " #alias); \ 610 __asm__(".set " #alias ", " #sym) 611 #else 612 #define __weak_reference(sym,alias) \ 613 __asm__(".weak_reference alias");\ 614 __asm__(".set alias, sym") 615 #endif 616 #else /* !__ELF__ && !__clang__ */ 617 #ifdef __STDC__ 618 #define __weak_reference(sym,alias) \ 619 __asm__(".stabs \"_" #alias "\",11,0,0,0"); \ 620 __asm__(".stabs \"_" #sym "\",1,0,0,0") 621 #else 622 #define __weak_reference(sym,alias) \ 623 __asm__(".stabs \"_/**/alias\",11,0,0,0"); \ 624 __asm__(".stabs \"_/**/sym\",1,0,0,0") 625 #endif 626 #endif 627 #endif 628 629 #endif /* __GNUC__ */ 630 631 #ifndef __FBSDID 632 #define __FBSDID(s) struct __hack 633 #endif 634 635 #ifndef __RCSID 636 #define __RCSID(s) struct __hack 637 #endif 638 639 #ifndef __RCSID_SOURCE 640 #define __RCSID_SOURCE(s) struct __hack 641 #endif 642 643 #ifndef __SCCSID 644 #define __SCCSID(s) struct __hack 645 #endif 646 647 #ifndef __COPYRIGHT 648 #define __COPYRIGHT(s) struct __hack 649 #endif 650 651 #ifndef __DECONST 652 #define __DECONST(type, var) ((type)(__uintptr_t)(const void *)(var)) 653 #endif 654 655 #ifndef __DEVOLATILE 656 #define __DEVOLATILE(type, var) ((type)(__uintptr_t)(volatile void *)(var)) 657 #endif 658 659 #ifndef __DEQUALIFY 660 #define __DEQUALIFY(type, var) ((type)(__uintptr_t)(const volatile void *)(var)) 661 #endif 662 663 /* 664 * Nullability qualifiers: currently only supported by Clang. 665 */ 666 #if !(defined(__clang__) && __has_feature(nullability)) 667 #define _Nonnull 668 #define _Nullable 669 #define _Null_unspecified 670 #define __NULLABILITY_PRAGMA_PUSH 671 #define __NULLABILITY_PRAGMA_POP 672 #else 673 #define __NULLABILITY_PRAGMA_PUSH _Pragma("clang diagnostic push") \ 674 _Pragma("clang diagnostic ignored \"-Wnullability-completeness\"") 675 #define __NULLABILITY_PRAGMA_POP _Pragma("clang diagnostic pop") 676 #endif 677 678 /* 679 * Type Safety Checking 680 * 681 * Clang provides additional attributes to enable checking type safety 682 * properties that cannot be enforced by the C type system. 683 */ 684 685 #if __has_attribute(__argument_with_type_tag__) && \ 686 __has_attribute(__type_tag_for_datatype__) 687 #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx) \ 688 __attribute__((__argument_with_type_tag__(arg_kind, arg_idx, type_tag_idx))) 689 #define __datatype_type_tag(kind, type) \ 690 __attribute__((__type_tag_for_datatype__(kind, type))) 691 #else 692 #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx) 693 #define __datatype_type_tag(kind, type) 694 #endif 695 696 /* 697 * Lock annotations. 698 * 699 * Clang provides support for doing basic thread-safety tests at 700 * compile-time, by marking which locks will/should be held when 701 * entering/leaving a functions. 702 * 703 * Furthermore, it is also possible to annotate variables and structure 704 * members to enforce that they are only accessed when certain locks are 705 * held. 706 */ 707 708 #if __has_extension(c_thread_safety_attributes) 709 #define __lock_annotate(x) __attribute__((x)) 710 #else 711 #define __lock_annotate(x) 712 #endif 713 714 /* Structure implements a lock. */ 715 /* FIXME: Use __lockable__, etc. to avoid colliding with user namespace macros, 716 * once clang is fixed: https://bugs.llvm.org/show_bug.cgi?id=34319 */ 717 #define __lockable __lock_annotate(lockable) 718 719 /* Function acquires an exclusive or shared lock. */ 720 #define __locks_exclusive(...) \ 721 __lock_annotate(exclusive_lock_function(__VA_ARGS__)) 722 #define __locks_shared(...) \ 723 __lock_annotate(shared_lock_function(__VA_ARGS__)) 724 725 /* Function attempts to acquire an exclusive or shared lock. */ 726 #define __trylocks_exclusive(...) \ 727 __lock_annotate(exclusive_trylock_function(__VA_ARGS__)) 728 #define __trylocks_shared(...) \ 729 __lock_annotate(shared_trylock_function(__VA_ARGS__)) 730 731 /* Function releases a lock. */ 732 #define __unlocks(...) __lock_annotate(unlock_function(__VA_ARGS__)) 733 734 /* Function asserts that an exclusive or shared lock is held. */ 735 #define __asserts_exclusive(...) \ 736 __lock_annotate(assert_exclusive_lock(__VA_ARGS__)) 737 #define __asserts_shared(...) \ 738 __lock_annotate(assert_shared_lock(__VA_ARGS__)) 739 740 /* Function requires that an exclusive or shared lock is or is not held. */ 741 #define __requires_exclusive(...) \ 742 __lock_annotate(exclusive_locks_required(__VA_ARGS__)) 743 #define __requires_shared(...) \ 744 __lock_annotate(shared_locks_required(__VA_ARGS__)) 745 #define __requires_unlocked(...) \ 746 __lock_annotate(locks_excluded(__VA_ARGS__)) 747 748 /* Function should not be analyzed. */ 749 #define __no_lock_analysis __lock_annotate(no_thread_safety_analysis) 750 751 /* 752 * Function or variable should not be sanitized, e.g., by AddressSanitizer. 753 * GCC has the nosanitize attribute, but as a function attribute only, and 754 * warns on use as a variable attribute. 755 */ 756 #if __has_attribute(no_sanitize) && defined(__clang__) 757 #ifdef _KERNEL 758 #define __nosanitizeaddress __attribute__((no_sanitize("kernel-address"))) 759 #define __nosanitizememory __attribute__((no_sanitize("kernel-memory"))) 760 #else 761 #define __nosanitizeaddress __attribute__((no_sanitize("address"))) 762 #define __nosanitizememory __attribute__((no_sanitize("memory"))) 763 #endif 764 #define __nosanitizethread __attribute__((no_sanitize("thread"))) 765 #else 766 #define __nosanitizeaddress 767 #define __nosanitizememory 768 #define __nosanitizethread 769 #endif 770 771 /* 772 * fall-through case statement annotations 773 */ 774 #if __cplusplus >= 201703L || __STDC_VERSION__ > 201710L 775 /* Standard C++17/C23 attribute */ 776 #define FALLTHROUGH [[fallthrough]] 777 #elif __has_attribute(fallthrough) 778 /* Non-standard but supported by at least gcc and clang */ 779 #define FALLTHROUGH __attribute__((fallthrough)) 780 #else 781 #define FALLTHROUGH do { } while(0) 782 #endif 783 784 /* Guard variables and structure members by lock. */ 785 #define __guarded_by(x) __lock_annotate(guarded_by(x)) 786 #define __pt_guarded_by(x) __lock_annotate(pt_guarded_by(x)) 787 788 /* Alignment builtins for better type checking and improved code generation. */ 789 /* Provide fallback versions for other compilers (GCC/Clang < 10): */ 790 #if !__has_builtin(__builtin_is_aligned) 791 #define __builtin_is_aligned(x, align) \ 792 (((__uintptr_t)x & ((align) - 1)) == 0) 793 #endif 794 #if !__has_builtin(__builtin_align_up) 795 #define __builtin_align_up(x, align) \ 796 ((__typeof__(x))(((__uintptr_t)(x)+((align)-1))&(~((align)-1)))) 797 #endif 798 #if !__has_builtin(__builtin_align_down) 799 #define __builtin_align_down(x, align) \ 800 ((__typeof__(x))((x)&(~((align)-1)))) 801 #endif 802 803 #define __align_up(x, y) __builtin_align_up(x, y) 804 #define __align_down(x, y) __builtin_align_down(x, y) 805 #define __is_aligned(x, y) __builtin_is_aligned(x, y) 806 807 #endif /* !_SYS_CDEFS_H_ */ 808
