newlib/libc/include/sys/cdefs.h

   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  * This code has been put in place to help reduce the addition of
 100  * compiler specific defines in FreeBSD code.  It helps to aid in
 101  * having a compiler-agnostic source tree.
 102  */
 103
 104 #if defined(__GNUC__)
 105
 106 #if __GNUC__ >= 3
 107 #define __GNUCLIKE_ASM 3
 108 #define __GNUCLIKE_MATH_BUILTIN_CONSTANTS
 109 #else
 110 #define __GNUCLIKE_ASM 2
 111 #endif
 112 #define __GNUCLIKE___TYPEOF 1
 113 #define __GNUCLIKE___SECTION 1
 114
 115 #define __GNUCLIKE_CTOR_SECTION_HANDLING 1
 116
 117 #define __GNUCLIKE_BUILTIN_CONSTANT_P 1
 118
 119 #if (__GNUC_MINOR__ > 95 || __GNUC__ >= 3)
 120 #define __GNUCLIKE_BUILTIN_VARARGS 1
 121 #define __GNUCLIKE_BUILTIN_STDARG 1
 122 #define __GNUCLIKE_BUILTIN_VAALIST 1
 123 #endif
 124
 125 #define __GNUC_VA_LIST_COMPATIBILITY 1
 126
 127 /*
 128  * Compiler memory barriers, specific to gcc and clang.
 129  */
 130 #define __compiler_membar()     __asm __volatile(" " : : : "memory")
 131
 132 #define __GNUCLIKE_BUILTIN_NEXT_ARG 1
 133 #define __GNUCLIKE_MATH_BUILTIN_RELOPS
 134
 135 #define __GNUCLIKE_BUILTIN_MEMCPY 1
 136
 137 /* XXX: if __GNUC__ >= 2: not tested everywhere originally, where replaced */
 138 #define __CC_SUPPORTS_INLINE 1
 139 #define __CC_SUPPORTS___INLINE 1
 140 #define __CC_SUPPORTS___INLINE__ 1
 141
 142 #define __CC_SUPPORTS___FUNC__ 1
 143 #define __CC_SUPPORTS_WARNING 1
 144
 145 #define __CC_SUPPORTS_VARADIC_XXX 1 /* see varargs.h */
 146
 147 #define __CC_SUPPORTS_DYNAMIC_ARRAY_INIT 1
 148
 149 #endif /* __GNUC__ */
 150
 151 /*
 152  * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
 153  * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
 154  * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI
 155  * mode -- there must be no spaces between its arguments, and for nested
 156  * __CONCAT's, all the __CONCAT's must be at the left.  __CONCAT can also
 157  * concatenate double-quoted strings produced by the __STRING macro, but
 158  * this only works with ANSI C.
 159  *
 160  * __XSTRING is like __STRING, but it expands any macros in its argument
 161  * first.  It is only available with ANSI C.
 162  */
 163 #if defined(__STDC__) || defined(__cplusplus)
 164 #define __P(protos)     protos          /* full-blown ANSI C */
 165 #define __CONCAT1(x,y)  x ## y
 166 #define __CONCAT(x,y)   __CONCAT1(x,y)
 167 #define __STRING(x)     #x              /* stringify without expanding x */
 168 #define __XSTRING(x)    __STRING(x)     /* expand x, then stringify */
 169
 170 #define __const         const           /* define reserved names to standard */
 171 #define __signed        signed
 172 #define __volatile      volatile
 173 #if defined(__cplusplus)
 174 #define __inline        inline          /* convert to C++ keyword */
 175 #else
 176 #if !(defined(__CC_SUPPORTS___INLINE))
 177 #define __inline                        /* delete GCC keyword */
 178 #endif /* ! __CC_SUPPORTS___INLINE */
 179 #endif /* !__cplusplus */
 180
 181 #else   /* !(__STDC__ || __cplusplus) */
 182 #define __P(protos)     ()              /* traditional C preprocessor */
 183 #define __CONCAT(x,y)   x/**/y
 184 #define __STRING(x)     "x"
 185
 186 #if !defined(__CC_SUPPORTS___INLINE)
 187 #define __const                         /* delete pseudo-ANSI C keywords */
 188 #define __inline
 189 #define __signed
 190 #define __volatile
 191 /*
 192  * In non-ANSI C environments, new programs will want ANSI-only C keywords
 193  * deleted from the program and old programs will want them left alone.
 194  * When using a compiler other than gcc, programs using the ANSI C keywords
 195  * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS.
 196  * When using "gcc -traditional", we assume that this is the intent; if
 197  * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone.
 198  */
 199 #ifndef NO_ANSI_KEYWORDS
 200 #define const                           /* delete ANSI C keywords */
 201 #define inline
 202 #define signed
 203 #define volatile
 204 #endif  /* !NO_ANSI_KEYWORDS */
 205 #endif  /* !__CC_SUPPORTS___INLINE */
 206 #endif  /* !(__STDC__ || __cplusplus) */
 207
 208 /*
 209  * Compiler-dependent macros to help declare dead (non-returning) and
 210  * pure (no side effects) functions, and unused variables.  They are
 211  * null except for versions of gcc that are known to support the features
 212  * properly (old versions of gcc-2 supported the dead and pure features
 213  * in a different (wrong) way).  If we do not provide an implementation
 214  * for a given compiler, let the compile fail if it is told to use
 215  * a feature that we cannot live without.
 216  */
 217 #define __weak_symbol   __attribute__((__weak__))
 218 #if !__GNUC_PREREQ__(2, 5)
 219 #define __dead2
 220 #define __pure2
 221 #define __unused
 222 #endif
 223 #if __GNUC__ == 2 && __GNUC_MINOR__ >= 5 && __GNUC_MINOR__ < 7
 224 #define __dead2         __attribute__((__noreturn__))
 225 #define __pure2         __attribute__((__const__))
 226 #define __unused
 227 /* XXX Find out what to do for __packed, __aligned and __section */
 228 #endif
 229 #if __GNUC_PREREQ__(2, 7)
 230 #define __dead2         __attribute__((__noreturn__))
 231 #define __pure2         __attribute__((__const__))
 232 #define __unused        __attribute__((__unused__))
 233 #define __used          __attribute__((__used__))
 234 #define __packed        __attribute__((__packed__))
 235 #define __aligned(x)    __attribute__((__aligned__(x)))
 236 #define __section(x)    __attribute__((__section__(x)))
 237 #endif
 238 #if __GNUC_PREREQ__(4, 3) || __has_attribute(__alloc_size__)
 239 #define __alloc_size(x) __attribute__((__alloc_size__(x)))
 240 #define __alloc_size2(n, x)     __attribute__((__alloc_size__(n, x)))
 241 #else
 242 #define __alloc_size(x)
 243 #define __alloc_size2(n, x)
 244 #endif
 245 #if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__)
 246 #define __alloc_align(x)        __attribute__((__alloc_align__(x)))
 247 #else
 248 #define __alloc_align(x)
 249 #endif
 250
 251 #if !__GNUC_PREREQ__(2, 95)
 252 #define __alignof(x)    __offsetof(struct { char __a; x __b; }, __b)
 253 #endif
 254
 255 /*
 256  * Keywords added in C11.
 257  */
 258
 259 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
 260
 261 #if !__has_extension(c_alignas)
 262 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
 263     __has_extension(cxx_alignas)
 264 #define _Alignas(x)             alignas(x)
 265 #else
 266 /* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */
 267 #define _Alignas(x)             __aligned(x)
 268 #endif
 269 #endif
 270
 271 #if defined(__cplusplus) && __cplusplus >= 201103L
 272 #define _Alignof(x)             alignof(x)
 273 #else
 274 #define _Alignof(x)             __alignof(x)
 275 #endif
 276
 277 #if !defined(__cplusplus) && !__has_extension(c_atomic) && \
 278         !__has_extension(cxx_atomic) && !__GNUC_PREREQ__(4, 7)
 279 /*
 280  * No native support for _Atomic(). Place object in structure to prevent
 281  * most forms of direct non-atomic access.
 282  */
 283 #define _Atomic(T)              struct { T volatile __val; }
 284 #endif
 285
 286 #if defined(__cplusplus) && __cplusplus >= 201103L
 287 #define _Noreturn               [[noreturn]]
 288 #else
 289 #define _Noreturn               __dead2
 290 #endif
 291
 292 #if !__has_extension(c_static_assert)
 293 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
 294     __has_extension(cxx_static_assert)
 295 #define _Static_assert(x, y)    static_assert(x, y)
 296 #elif __GNUC_PREREQ__(4,6) && !defined(__cplusplus)
 297 /* Nothing, gcc 4.6 and higher has _Static_assert built-in */
 298 #elif defined(__COUNTER__)
 299 #define _Static_assert(x, y)    __Static_assert(x, __COUNTER__)
 300 #define __Static_assert(x, y)   ___Static_assert(x, y)
 301 #define ___Static_assert(x, y)  typedef char __assert_ ## y[(x) ? 1 : -1] \
 302                                 __unused
 303 #else
 304 #define _Static_assert(x, y)    struct __hack
 305 #endif
 306 #endif
 307
 308 #if !__has_extension(c_thread_local)
 309 /*
 310  * XXX: Some compilers (Clang 3.3, GCC 4.7) falsely announce C++11 mode
 311  * without actually supporting the thread_local keyword. Don't check for
 312  * the presence of C++11 when defining _Thread_local.
 313  */
 314 #if /* (defined(__cplusplus) && __cplusplus >= 201103L) || */ \
 315     __has_extension(cxx_thread_local)
 316 #define _Thread_local           thread_local
 317 #else
 318 #define _Thread_local           __thread
 319 #endif
 320 #endif
 321
 322 #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */
 323
 324 /*
 325  * Emulation of C11 _Generic().  Unlike the previously defined C11
 326  * keywords, it is not possible to implement this using exactly the same
 327  * syntax.  Therefore implement something similar under the name
 328  * __generic().  Unlike _Generic(), this macro can only distinguish
 329  * between a single type, so it requires nested invocations to
 330  * distinguish multiple cases.
 331  *
 332  * Note that the comma operator is used to force expr to decay in
 333  * order to match _Generic().
 334  */
 335
 336 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \
 337     __has_extension(c_generic_selections)
 338 #define __generic(expr, t, yes, no)                                     \
 339         _Generic(expr, t: yes, default: no)
 340 #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus)
 341 #define __generic(expr, t, yes, no)                                     \
 342         __builtin_choose_expr(                                          \
 343             __builtin_types_compatible_p(__typeof((0, (expr))), t), yes, no)
 344 #endif
 345
 346 /*
 347  * C99 Static array indices in function parameter declarations.  Syntax such as:
 348  * void bar(int myArray[static 10]);
 349  * is allowed in C99 but not in C++.  Define __min_size appropriately so
 350  * headers using it can be compiled in either language.  Use like this:
 351  * void bar(int myArray[__min_size(10)]);
 352  */
 353 #if !defined(__cplusplus) && \
 354     (defined(__clang__) || __GNUC_PREREQ__(4, 6)) && \
 355     (!defined(__STDC_VERSION__) || (__STDC_VERSION__ >= 199901))
 356 #define __min_size(x)   static (x)
 357 #else
 358 #define __min_size(x)   (x)
 359 #endif
 360
 361 #if __GNUC_PREREQ__(2, 96)
 362 #define __malloc_like   __attribute__((__malloc__))
 363 #define __pure          __attribute__((__pure__))
 364 #else
 365 #define __malloc_like
 366 #define __pure
 367 #endif
 368
 369 #if __GNUC_PREREQ__(3, 1)
 370 #define __always_inline __inline__ __attribute__((__always_inline__))
 371 #else
 372 #define __always_inline
 373 #endif
 374
 375 #if __GNUC_PREREQ__(3, 1)
 376 #define __noinline      __attribute__ ((__noinline__))
 377 #else
 378 #define __noinline
 379 #endif
 380
 381 #if __GNUC_PREREQ__(3, 3)
 382 #define __nonnull(x)    __attribute__((__nonnull__ x))
 383 #define __nonnull_all   __attribute__((__nonnull__))
 384 #else
 385 #define __nonnull(x)
 386 #define __nonnull_all
 387 #endif
 388
 389 #if __GNUC_PREREQ__(3, 4)
 390 #define __fastcall      __attribute__((__fastcall__))
 391 #define __result_use_check      __attribute__((__warn_unused_result__))
 392 #else
 393 #define __fastcall
 394 #define __result_use_check
 395 #endif
 396
 397 #if __GNUC_PREREQ__(4, 1)
 398 #define __returns_twice __attribute__((__returns_twice__))
 399 #else
 400 #define __returns_twice
 401 #endif
 402
 403 #if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable)
 404 #define __unreachable() __builtin_unreachable()
 405 #else
 406 #define __unreachable() ((void)0)
 407 #endif
 408
 409 /* XXX: should use `#if __STDC_VERSION__ < 199901'. */
 410 #if !__GNUC_PREREQ__(2, 7)
 411 #define __func__        NULL
 412 #endif
 413
 414 /*
 415  * We use `__restrict' as a way to define the `restrict' type qualifier
 416  * without disturbing older software that is unaware of C99 keywords.
 417  * GCC also provides `__restrict' as an extension to support C99-style
 418  * restricted pointers in other language modes.
 419  */
 420 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901
 421 #define __restrict      restrict
 422 #elif !__GNUC_PREREQ__(2, 95)
 423 #define __restrict
 424 #endif
 425
 426 /*
 427  * Additionally, we allow to use `__restrict_arr' for declaring arrays as
 428  * non-overlapping per C99.  That's supported since gcc 3.1, but it's not
 429  * allowed in C++.
 430  */
 431 #if defined(__cplusplus) || !__GNUC_PREREQ__(3, 1)
 432 #define __restrict_arr
 433 #elif defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
 434 #define __restrict_arr       restrict
 435 #else
 436 #define __restrict_arr
 437 #endif
 438
 439 /*
 440  * GNU C version 2.96 adds explicit branch prediction so that
 441  * the CPU back-end can hint the processor and also so that
 442  * code blocks can be reordered such that the predicted path
 443  * sees a more linear flow, thus improving cache behavior, etc.
 444  *
 445  * The following two macros provide us with a way to utilize this
 446  * compiler feature.  Use __predict_true() if you expect the expression
 447  * to evaluate to true, and __predict_false() if you expect the
 448  * expression to evaluate to false.
 449  *
 450  * A few notes about usage:
 451  *
 452  *      * Generally, __predict_false() error condition checks (unless
 453  *        you have some _strong_ reason to do otherwise, in which case
 454  *        document it), and/or __predict_true() `no-error' condition
 455  *        checks, assuming you want to optimize for the no-error case.
 456  *
 457  *      * Other than that, if you don't know the likelihood of a test
 458  *        succeeding from empirical or other `hard' evidence, don't
 459  *        make predictions.
 460  *
 461  *      * These are meant to be used in places that are run `a lot'.
 462  *        It is wasteful to make predictions in code that is run
 463  *        seldomly (e.g. at subsystem initialization time) as the
 464  *        basic block reordering that this affects can often generate
 465  *        larger code.
 466  */
 467 #if __GNUC_PREREQ__(2, 96)
 468 #define __predict_true(exp)     __builtin_expect((exp), 1)
 469 #define __predict_false(exp)    __builtin_expect((exp), 0)
 470 #else
 471 #define __predict_true(exp)     (exp)
 472 #define __predict_false(exp)    (exp)
 473 #endif
 474
 475 #if __GNUC_PREREQ__(4, 0)
 476 #define __null_sentinel __attribute__((__sentinel__))
 477 #define __exported      __attribute__((__visibility__("default")))
 478 /* Only default visibility is supported on PE/COFF targets. */
 479 #ifndef __CYGWIN__
 480 #define __hidden        __attribute__((__visibility__("hidden")))
 481 #else
 482 #define __hidden
 483 #endif
 484 #else
 485 #define __null_sentinel
 486 #define __exported
 487 #define __hidden
 488 #endif
 489
 490 #define __offsetof(type, field) offsetof(type, field)
 491 #define __rangeof(type, start, end) \
 492         (__offsetof(type, end) - __offsetof(type, start))
 493
 494 /*
 495  * Given the pointer x to the member m of the struct s, return
 496  * a pointer to the containing structure.  When using GCC, we first
 497  * assign pointer x to a local variable, to check that its type is
 498  * compatible with member m.
 499  */
 500 #if __GNUC_PREREQ__(3, 1)
 501 #define __containerof(x, s, m) ({                                       \
 502         const volatile __typeof(((s *)0)->m) *__x = (x);                \
 503         __DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m));\
 504 })
 505 #else
 506 #define __containerof(x, s, m)                                          \
 507         __DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m))
 508 #endif
 509
 510 /*
 511  * Compiler-dependent macros to declare that functions take printf-like
 512  * or scanf-like arguments.  They are null except for versions of gcc
 513  * that are known to support the features properly (old versions of gcc-2
 514  * didn't permit keeping the keywords out of the application namespace).
 515  */
 516 #if !__GNUC_PREREQ__(2, 7)
 517 #define __printflike(fmtarg, firstvararg)
 518 #define __scanflike(fmtarg, firstvararg)
 519 #define __format_arg(fmtarg)
 520 #define __strfmonlike(fmtarg, firstvararg)
 521 #define __strftimelike(fmtarg, firstvararg)
 522 #else
 523 #define __printflike(fmtarg, firstvararg) \
 524             __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
 525 #define __scanflike(fmtarg, firstvararg) \
 526             __attribute__((__format__ (__scanf__, fmtarg, firstvararg)))
 527 #define __format_arg(fmtarg)    __attribute__((__format_arg__ (fmtarg)))
 528 #define __strfmonlike(fmtarg, firstvararg) \
 529             __attribute__((__format__ (__strfmon__, fmtarg, firstvararg)))
 530 #define __strftimelike(fmtarg, firstvararg) \
 531             __attribute__((__format__ (__strftime__, fmtarg, firstvararg)))
 532 #endif
 533
 534 /* Compiler-dependent macros that rely on FreeBSD-specific extensions. */
 535 #if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \
 536     defined(__GNUC__)
 537 #define __printf0like(fmtarg, firstvararg) \
 538             __attribute__((__format__ (__printf0__, fmtarg, firstvararg)))
 539 #else
 540 #define __printf0like(fmtarg, firstvararg)
 541 #endif
 542
 543 #if defined(__GNUC__)
 544 #define __strong_reference(sym,aliassym)        \
 545         extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym)))
 546 #ifdef __ELF__
 547 #ifdef __STDC__
 548 #define __weak_reference(sym,alias)     \
 549         __asm__(".weak " #alias);       \
 550         __asm__(".equ "  #alias ", " #sym)
 551 #define __warn_references(sym,msg)      \
 552         __asm__(".section .gnu.warning." #sym); \
 553         __asm__(".asciz \"" msg "\"");  \
 554         __asm__(".previous")
 555 #define __sym_compat(sym,impl,verid)    \
 556         __asm__(".symver " #impl ", " #sym "@" #verid)
 557 #define __sym_default(sym,impl,verid)   \
 558         __asm__(".symver " #impl ", " #sym "@@" #verid)
 559 #else
 560 #define __weak_reference(sym,alias)     \
 561         __asm__(".weak alias");         \
 562         __asm__(".equ alias, sym")
 563 #define __warn_references(sym,msg)      \
 564         __asm__(".section .gnu.warning.sym"); \
 565         __asm__(".asciz \"msg\"");      \
 566         __asm__(".previous")
 567 #define __sym_compat(sym,impl,verid)    \
 568         __asm__(".symver impl, sym@verid")
 569 #define __sym_default(impl,sym,verid)   \
 570         __asm__(".symver impl, sym@@verid")
 571 #endif  /* __STDC__ */
 572 #else   /* !__ELF__ */
 573 #ifdef __STDC__
 574 #define __weak_reference(sym,alias)     \
 575         __asm__(".stabs \"_" #alias "\",11,0,0,0");     \
 576         __asm__(".stabs \"_" #sym "\",1,0,0,0")
 577 #define __warn_references(sym,msg)      \
 578         __asm__(".stabs \"" msg "\",30,0,0,0");         \
 579         __asm__(".stabs \"_" #sym "\",1,0,0,0")
 580 #else
 581 #define __weak_reference(sym,alias)     \
 582         __asm__(".stabs \"_/**/alias\",11,0,0,0");      \
 583         __asm__(".stabs \"_/**/sym\",1,0,0,0")
 584 #define __warn_references(sym,msg)      \
 585         __asm__(".stabs msg,30,0,0,0");                 \
 586         __asm__(".stabs \"_/**/sym\",1,0,0,0")
 587 #endif  /* __STDC__ */
 588 #endif  /* __ELF__ */
 589 #endif  /* __GNUC__ */
 590
 591 #ifndef __FBSDID
 592 #define __FBSDID(s)     struct __hack
 593 #endif
 594
 595 #ifndef __RCSID
 596 #define __RCSID(s)      struct __hack
 597 #endif
 598
 599 #ifndef __RCSID_SOURCE
 600 #define __RCSID_SOURCE(s)       struct __hack
 601 #endif
 602
 603 #ifndef __SCCSID
 604 #define __SCCSID(s)     struct __hack
 605 #endif
 606
 607 #ifndef __COPYRIGHT
 608 #define __COPYRIGHT(s)  struct __hack
 609 #endif
 610
 611 #ifndef __DECONST
 612 #define __DECONST(type, var)    ((type)(__uintptr_t)(const void *)(var))
 613 #endif
 614
 615 #ifndef __DEVOLATILE
 616 #define __DEVOLATILE(type, var) ((type)(__uintptr_t)(volatile void *)(var))
 617 #endif
 618
 619 #ifndef __DEQUALIFY
 620 #define __DEQUALIFY(type, var)  ((type)(__uintptr_t)(const volatile void *)(var))
 621 #endif
 622
 623 /*
 624  * Nullability qualifiers: currently only supported by Clang.
 625  */
 626 #if !(defined(__clang__) && __has_feature(nullability))
 627 #define _Nonnull
 628 #define _Nullable
 629 #define _Null_unspecified
 630 #define __NULLABILITY_PRAGMA_PUSH
 631 #define __NULLABILITY_PRAGMA_POP
 632 #else
 633 #define __NULLABILITY_PRAGMA_PUSH _Pragma("clang diagnostic push")      \
 634         _Pragma("clang diagnostic ignored \"-Wnullability-completeness\"")
 635 #define __NULLABILITY_PRAGMA_POP _Pragma("clang diagnostic pop")
 636 #endif
 637
 638 /*
 639  * Type Safety Checking
 640  *
 641  * Clang provides additional attributes to enable checking type safety
 642  * properties that cannot be enforced by the C type system.
 643  */
 644
 645 #if __has_attribute(__argument_with_type_tag__) && \
 646     __has_attribute(__type_tag_for_datatype__)
 647 #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx) \
 648             __attribute__((__argument_with_type_tag__(arg_kind, arg_idx, type_tag_idx)))
 649 #define __datatype_type_tag(kind, type) \
 650             __attribute__((__type_tag_for_datatype__(kind, type)))
 651 #else
 652 #define __arg_type_tag(arg_kind, arg_idx, type_tag_idx)
 653 #define __datatype_type_tag(kind, type)
 654 #endif
 655
 656 /*
 657  * Lock annotations.
 658  *
 659  * Clang provides support for doing basic thread-safety tests at
 660  * compile-time, by marking which locks will/should be held when
 661  * entering/leaving a functions.
 662  *
 663  * Furthermore, it is also possible to annotate variables and structure
 664  * members to enforce that they are only accessed when certain locks are
 665  * held.
 666  */
 667
 668 #if __has_extension(c_thread_safety_attributes)
 669 #define __lock_annotate(x)      __attribute__((x))
 670 #else
 671 #define __lock_annotate(x)
 672 #endif
 673
 674 /* Structure implements a lock. */
 675 /* FIXME: Use __lockable__, etc. to avoid colliding with user namespace macros,
 676  * once clang is fixed: https://bugs.llvm.org/show_bug.cgi?id=34319 */
 677 #define __lockable              __lock_annotate(lockable)
 678
 679 /* Function acquires an exclusive or shared lock. */
 680 #define __locks_exclusive(...) \
 681         __lock_annotate(exclusive_lock_function(__VA_ARGS__))
 682 #define __locks_shared(...) \
 683         __lock_annotate(shared_lock_function(__VA_ARGS__))
 684
 685 /* Function attempts to acquire an exclusive or shared lock. */
 686 #define __trylocks_exclusive(...) \
 687         __lock_annotate(exclusive_trylock_function(__VA_ARGS__))
 688 #define __trylocks_shared(...) \
 689         __lock_annotate(shared_trylock_function(__VA_ARGS__))
 690
 691 /* Function releases a lock. */
 692 #define __unlocks(...)          __lock_annotate(unlock_function(__VA_ARGS__))
 693
 694 /* Function asserts that an exclusive or shared lock is held. */
 695 #define __asserts_exclusive(...) \
 696         __lock_annotate(assert_exclusive_lock(__VA_ARGS__))
 697 #define __asserts_shared(...) \
 698         __lock_annotate(assert_shared_lock(__VA_ARGS__))
 699
 700 /* Function requires that an exclusive or shared lock is or is not held. */
 701 #define __requires_exclusive(...) \
 702         __lock_annotate(exclusive_locks_required(__VA_ARGS__))
 703 #define __requires_shared(...) \
 704         __lock_annotate(shared_locks_required(__VA_ARGS__))
 705 #define __requires_unlocked(...) \
 706         __lock_annotate(locks_excluded(__VA_ARGS__))
 707
 708 /* Function should not be analyzed. */
 709 #define __no_lock_analysis      __lock_annotate(no_thread_safety_analysis)
 710
 711 /*
 712  * Function or variable should not be sanitized, e.g., by AddressSanitizer.
 713  * GCC has the nosanitize attribute, but as a function attribute only, and
 714  * warns on use as a variable attribute.
 715  */
 716 #if __has_attribute(no_sanitize) && defined(__clang__)
 717 #ifdef _KERNEL
 718 #define __nosanitizeaddress     __attribute__((no_sanitize("kernel-address")))
 719 #define __nosanitizememory      __attribute__((no_sanitize("kernel-memory")))
 720 #else
 721 #define __nosanitizeaddress     __attribute__((no_sanitize("address")))
 722 #define __nosanitizememory      __attribute__((no_sanitize("memory")))
 723 #endif
 724 #define __nosanitizethread      __attribute__((no_sanitize("thread")))
 725 #else
 726 #define __nosanitizeaddress
 727 #define __nosanitizememory
 728 #define __nosanitizethread
 729 #endif
 730
 731 /* Guard variables and structure members by lock. */
 732 #define __guarded_by(x)         __lock_annotate(guarded_by(x))
 733 #define __pt_guarded_by(x)      __lock_annotate(pt_guarded_by(x))
 734
 735 /* Alignment builtins for better type checking and improved code generation. */
 736 /* Provide fallback versions for other compilers (GCC/Clang < 10): */
 737 #if !__has_builtin(__builtin_is_aligned)
 738 #define __builtin_is_aligned(x, align)  \
 739         (((__uintptr_t)x & ((align) - 1)) == 0)
 740 #endif
 741 #if !__has_builtin(__builtin_align_up)
 742 #define __builtin_align_up(x, align)    \
 743         ((__typeof__(x))(((__uintptr_t)(x)+((align)-1))&(~((align)-1))))
 744 #endif
 745 #if !__has_builtin(__builtin_align_down)
 746 #define __builtin_align_down(x, align)  \
 747         ((__typeof__(x))((x)&(~((align)-1))))
 748 #endif
 749
 750 #define __align_up(x, y) __builtin_align_up(x, y)
 751 #define __align_down(x, y) __builtin_align_down(x, y)
 752 #define __is_aligned(x, y) __builtin_is_aligned(x, y)
 753
 754 #endif /* !_SYS_CDEFS_H_ */