lib/compiler.h

   1 /*
   2  * Copyright (c) 2015-2017  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef _FRR_COMPILER_H
  18 #define _FRR_COMPILER_H
  19
  20 #ifdef __cplusplus
  21 extern "C" {
  22 #endif
  23
  24 #ifdef __cplusplus
  25 # if __cplusplus < 201103L
  26 #  error FRRouting headers must be compiled in C++11 mode or newer
  27 # endif
  28 /* C++ defines static_assert(), but not _Static_assert().  C defines
  29  * _Static_assert() and has static_assert() in <assert.h>.  However, we mess
  30  * with assert() in zassert.h so let's not include <assert.h> here.
  31  */
  32 # define _Static_assert static_assert
  33 #else
  34 # if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
  35 #  error FRRouting must be compiled with min. -std=gnu11 (GNU ISO C11 dialect)
  36 # endif
  37 #endif
  38
  39 /* function attributes, use like
  40  *   void prototype(void) __attribute__((_CONSTRUCTOR(100)));
  41  */
  42 #if defined(__clang__)
  43 #if __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 5)
  44 #  define _RET_NONNULL    , returns_nonnull
  45 #endif
  46 #if __has_attribute(fallthrough)
  47 #  define _FALLTHROUGH __attribute__((fallthrough));
  48 #endif
  49 # define _CONSTRUCTOR(x)  constructor(x)
  50 # define _DEPRECATED(x) deprecated(x)
  51 # if __has_builtin(assume)
  52 #  define assume(x) __builtin_assume(x)
  53 # endif
  54 #elif defined(__GNUC__)
  55 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9)
  56 #  define _RET_NONNULL    , returns_nonnull
  57 #endif
  58 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
  59 #  define _CONSTRUCTOR(x) constructor(x)
  60 #  define _DESTRUCTOR(x)  destructor(x)
  61 #  define _ALLOC_SIZE(x)  alloc_size(x)
  62 #endif
  63 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
  64 #  define _DEPRECATED(x) deprecated(x)
  65 #  define assume(x) do { if (!(x)) __builtin_unreachable(); } while (0)
  66 #endif
  67 #if __GNUC__ < 5
  68 #  define __has_attribute(x) 0
  69 #endif
  70 #if __GNUC__ >= 7
  71 #  define _FALLTHROUGH __attribute__((fallthrough));
  72 #endif
  73 #endif
  74
  75 #ifdef __INTELLISENSE__
  76 /*
  77  * Fix Visual Studio Code error: attribute "constructor" does not take
  78  * arguments.
  79  *
  80  * Caused by the macro `DEFINE_MTYPE_ATTR` in `lib/memory.h`.
  81  */
  82 #pragma diag_suppress 1094
  83 #endif /* __INTELISENSE__ */
  84
  85 #if __has_attribute(hot)
  86 #  define _OPTIMIZE_HOT __attribute__((hot))
  87 #else
  88 #  define _OPTIMIZE_HOT
  89 #endif
  90 #if __has_attribute(optimize)
  91 #  define _OPTIMIZE_O3 __attribute__((optimize("3")))
  92 #else
  93 #  define _OPTIMIZE_O3
  94 #endif
  95 #define OPTIMIZE _OPTIMIZE_O3 _OPTIMIZE_HOT
  96
  97 #if !defined(__GNUC__)
  98 #error module code needs GCC visibility extensions
  99 #elif __GNUC__ < 4
 100 #error module code needs GCC visibility extensions
 101 #else
 102 # define DSO_PUBLIC __attribute__ ((visibility ("default")))
 103 # define DSO_SELF   __attribute__ ((visibility ("protected")))
 104 # define DSO_LOCAL  __attribute__ ((visibility ("hidden")))
 105 #endif
 106
 107 #ifdef __sun
 108 /* Solaris doesn't do constructor priorities due to linker restrictions */
 109 #undef _CONSTRUCTOR
 110 #undef _DESTRUCTOR
 111 #endif
 112
 113 /* fallback versions */
 114 #ifndef _RET_NONNULL
 115 # define _RET_NONNULL
 116 #endif
 117 #ifndef _CONSTRUCTOR
 118 # define _CONSTRUCTOR(x) constructor
 119 #endif
 120 #ifndef _DESTRUCTOR
 121 # define _DESTRUCTOR(x) destructor
 122 #endif
 123 #ifndef _ALLOC_SIZE
 124 # define _ALLOC_SIZE(x)
 125 #endif
 126 #ifndef _FALLTHROUGH
 127 #define _FALLTHROUGH
 128 #endif
 129 #ifndef _DEPRECATED
 130 #define _DEPRECATED(x) deprecated
 131 #endif
 132 #ifndef assume
 133 #define assume(x)
 134 #endif
 135
 136 /* for helper functions defined inside macros */
 137 #define macro_inline    static inline __attribute__((unused))
 138 #define macro_pure      static inline __attribute__((unused, pure))
 139
 140 /* if the macro ends with a function definition */
 141 #define MACRO_REQUIRE_SEMICOLON() \
 142         _Static_assert(1, "please add a semicolon after this macro")
 143
 144 /* variadic macros, use like:
 145  * #define V_0()  ...
 146  * #define V_1(x) ...
 147  * #define V(...) MACRO_VARIANT(V, ##__VA_ARGS__)(__VA_ARGS__)
 148  */
 149 #define _MACRO_VARIANT(A0,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10, N, ...) N
 150
 151 #define _CONCAT2(a, b) a ## b
 152 #define _CONCAT(a, b) _CONCAT2(a,b)
 153
 154 #define MACRO_VARIANT(NAME, ...) \
 155         _CONCAT(NAME, _MACRO_VARIANT(0, ##__VA_ARGS__, \
 156                         _10, _9, _8, _7, _6, _5, _4, _3, _2, _1, _0))
 157
 158 #define NAMECTR(name) _CONCAT(name, __COUNTER__)
 159
 160 /* per-arg repeat macros, use like:
 161  * #define PERARG(n) ...n...
 162  * #define FOO(...) MACRO_REPEAT(PERARG, ##__VA_ARGS__)
 163  */
 164
 165 #define _MACRO_REPEAT_0(NAME)
 166 #define _MACRO_REPEAT_1(NAME, A1) \
 167         NAME(A1)
 168 #define _MACRO_REPEAT_2(NAME, A1, A2) \
 169         NAME(A1) NAME(A2)
 170 #define _MACRO_REPEAT_3(NAME, A1, A2, A3) \
 171         NAME(A1) NAME(A2) NAME(A3)
 172 #define _MACRO_REPEAT_4(NAME, A1, A2, A3, A4) \
 173         NAME(A1) NAME(A2) NAME(A3) NAME(A4)
 174 #define _MACRO_REPEAT_5(NAME, A1, A2, A3, A4, A5) \
 175         NAME(A1) NAME(A2) NAME(A3) NAME(A4) NAME(A5)
 176 #define _MACRO_REPEAT_6(NAME, A1, A2, A3, A4, A5, A6) \
 177         NAME(A1) NAME(A2) NAME(A3) NAME(A4) NAME(A5) NAME(A6)
 178 #define _MACRO_REPEAT_7(NAME, A1, A2, A3, A4, A5, A6, A7) \
 179         NAME(A1) NAME(A2) NAME(A3) NAME(A4) NAME(A5) NAME(A6) NAME(A7)
 180 #define _MACRO_REPEAT_8(NAME, A1, A2, A3, A4, A5, A6, A7, A8) \
 181         NAME(A1) NAME(A2) NAME(A3) NAME(A4) NAME(A5) NAME(A6) NAME(A7) NAME(A8)
 182
 183 #define MACRO_REPEAT(NAME, ...) \
 184         MACRO_VARIANT(_MACRO_REPEAT, ##__VA_ARGS__)(NAME, ##__VA_ARGS__)
 185
 186 /* per-arglist repeat macro, use like this:
 187  * #define foo(...) MAP_LISTS(F, ##__VA_ARGS__)
 188  * where F is a n-ary function where n is the number of args in each arglist.
 189  * e.g.: MAP_LISTS(f, (a, b), (c, d))
 190  * expands to: f(a, b); f(c, d)
 191  */
 192
 193 #define ESC(...) __VA_ARGS__
 194 #define MAP_LISTS(M, ...)                                                      \
 195         _CONCAT(_MAP_LISTS_, PP_NARG(__VA_ARGS__))(M, ##__VA_ARGS__)
 196 #define _MAP_LISTS_0(M)
 197 #define _MAP_LISTS_1(M, _1) ESC(M _1)
 198 #define _MAP_LISTS_2(M, _1, _2) ESC(M _1; M _2)
 199 #define _MAP_LISTS_3(M, _1, _2, _3) ESC(M _1; M _2; M _3)
 200 #define _MAP_LISTS_4(M, _1, _2, _3, _4) ESC(M _1; M _2; M _3; M _4)
 201 #define _MAP_LISTS_5(M, _1, _2, _3, _4, _5) ESC(M _1; M _2; M _3; M _4; M _5)
 202 #define _MAP_LISTS_6(M, _1, _2, _3, _4, _5, _6)                                \
 203         ESC(M _1; M _2; M _3; M _4; M _5; M _6)
 204 #define _MAP_LISTS_7(M, _1, _2, _3, _4, _5, _6, _7)                            \
 205         ESC(M _1; M _2; M _3; M _4; M _5; M _6; M _7)
 206 #define _MAP_LISTS_8(M, _1, _2, _3, _4, _5, _6, _7, _8)                        \
 207         ESC(M _1; M _2; M _3; M _4; M _5; M _6; M _7; M _8)
 208
 209 /*
 210  * for warnings on macros, put in the macro content like this:
 211  *   #define MACRO BLA CPP_WARN("MACRO has been deprecated")
 212  */
 213 #define CPP_STR(X) #X
 214
 215 #if defined(__ICC)
 216 #define CPP_NOTICE(text) _Pragma(CPP_STR(message __FILE__ ": " text))
 217 #define CPP_WARN(text) CPP_NOTICE(text)
 218
 219 #elif (defined(__GNUC__)                                                       \
 220        && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))           \
 221         || (defined(__clang__)                                                 \
 222             && (__clang_major__ >= 4                                           \
 223                 || (__clang_major__ == 3 && __clang_minor__ >= 5)))
 224 #define CPP_WARN(text) _Pragma(CPP_STR(GCC warning text))
 225 #define CPP_NOTICE(text) _Pragma(CPP_STR(message text))
 226
 227 #else
 228 #define CPP_WARN(text)
 229 #define CPP_NOTICE(text)
 230 #endif
 231
 232 /* MAX / MIN are not commonly defined, but useful */
 233 /* note: glibc sys/param.h has #define MIN(a,b) (((a)<(b))?(a):(b)) */
 234 #ifdef MAX
 235 #undef MAX
 236 #endif
 237 #define MAX(a, b)                                                              \
 238         ({                                                                     \
 239                 typeof(a) _max_a = (a);                                        \
 240                 typeof(b) _max_b = (b);                                        \
 241                 _max_a > _max_b ? _max_a : _max_b;                             \
 242         })
 243 #ifdef MIN
 244 #undef MIN
 245 #endif
 246 #define MIN(a, b)                                                              \
 247         ({                                                                     \
 248                 typeof(a) _min_a = (a);                                        \
 249                 typeof(b) _min_b = (b);                                        \
 250                 _min_a < _min_b ? _min_a : _min_b;                             \
 251         })
 252
 253 #define numcmp(a, b)                                                           \
 254         ({                                                                     \
 255                 typeof(a) _cmp_a = (a);                                        \
 256                 typeof(b) _cmp_b = (b);                                        \
 257                 (_cmp_a < _cmp_b) ? -1 : ((_cmp_a > _cmp_b) ? 1 : 0);          \
 258         })
 259
 260 #ifndef offsetof
 261 #ifdef __compiler_offsetof
 262 #define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE,MEMBER)
 263 #else
 264 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 265 #endif
 266 #endif
 267
 268 #ifdef container_of
 269 #undef container_of
 270 #endif
 271
 272 #if !(defined(__cplusplus) || defined(test__cplusplus))
 273 /* this variant of container_of() retains 'const' on pointers without needing
 274  * to be told to do so.  The following will all work without warning:
 275  *
 276  * struct member *p;
 277  * const struct member *cp;
 278  *
 279  * const struct cont *x = container_of(cp, struct cont, member);
 280  * const struct cont *x = container_of(cp, const struct cont, member);
 281  * const struct cont *x = container_of(p,  struct cont, member);
 282  * const struct cont *x = container_of(p,  const struct cont, member);
 283  * struct cont *x       = container_of(p,  struct cont, member);
 284  *
 285  * but the following will generate warnings about stripping const:
 286  *
 287  * struct cont *x       = container_of(cp, struct cont, member);
 288  * struct cont *x       = container_of(cp, const struct cont, member);
 289  * struct cont *x       = container_of(p,  const struct cont, member);
 290  */
 291 #define container_of(ptr, type, member)                                        \
 292         (__builtin_choose_expr(                                                \
 293                 __builtin_types_compatible_p(typeof(&((type *)0)->member),     \
 294                         typeof(ptr))                                           \
 295                     ||  __builtin_types_compatible_p(void *, typeof(ptr)),     \
 296                 ({                                                             \
 297                         typeof(((type *)0)->member) *__mptr = (void *)(ptr);   \
 298                         (type *)((char *)__mptr - offsetof(type, member));     \
 299                 }),                                                            \
 300                 ({                                                             \
 301                         typeof(((const type *)0)->member) *__mptr = (ptr);     \
 302                         (const type *)((const char *)__mptr -                  \
 303                                         offsetof(type, member));               \
 304                 })                                                             \
 305         ))
 306 #else
 307 /* current C++ compilers don't have the builtins used above; so this version
 308  * of the macro doesn't do the const check. */
 309 #define container_of(ptr, type, member)                                        \
 310                 ({                                                             \
 311                         const typeof(((type *)0)->member) *__mptr = (ptr);     \
 312                         (type *)((char *)__mptr - offsetof(type, member));     \
 313                 })
 314 #endif
 315
 316 #define container_of_null(ptr, type, member)                                   \
 317         ({                                                                     \
 318                 typeof(ptr) _tmp = (ptr);                                      \
 319                 _tmp ? container_of(_tmp, type, member) : NULL;                \
 320         })
 321
 322 #define array_size(ar) (sizeof(ar) / sizeof(ar[0]))
 323
 324 /* Some insane macros to count number of varargs to a functionlike macro */
 325 #define PP_ARG_N( \
 326           _1,  _2,  _3,  _4,  _5,  _6,  _7,  _8,  _9, _10, \
 327          _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, \
 328          _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, \
 329          _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, \
 330          _41, _42, _43, _44, _45, _46, _47, _48, _49, _50, \
 331          _51, _52, _53, _54, _55, _56, _57, _58, _59, _60, \
 332          _61, _62, _63, N, ...) N
 333
 334 #define PP_RSEQ_N()                                        \
 335          62, 61, 60,                                       \
 336          59, 58, 57, 56, 55, 54, 53, 52, 51, 50,           \
 337          49, 48, 47, 46, 45, 44, 43, 42, 41, 40,           \
 338          39, 38, 37, 36, 35, 34, 33, 32, 31, 30,           \
 339          29, 28, 27, 26, 25, 24, 23, 22, 21, 20,           \
 340          19, 18, 17, 16, 15, 14, 13, 12, 11, 10,           \
 341           9,  8,  7,  6,  5,  4,  3,  2,  1,  0
 342
 343 #define PP_NARG_(...) PP_ARG_N(__VA_ARGS__)
 344 #define PP_NARG(...)     PP_NARG_(_, ##__VA_ARGS__, PP_RSEQ_N())
 345
 346
 347 /* sigh. this is so ugly, it overflows and wraps to being nice again.
 348  *
 349  * printfrr() supports "%Ld" for <int64_t>, whatever that is typedef'd to.
 350  * However, gcc & clang think that "%Ld" is <long long>, which doesn't quite
 351  * match up since int64_t is <long> on a lot of 64-bit systems.
 352  *
 353  * If we have _FRR_ATTRIBUTE_PRINTFRR, we loaded a compiler plugin that
 354  * replaces the whole format checking bits with a custom version that
 355  * understands "%Ld" (along with "%pI4" and co.), so we don't need to do
 356  * anything.
 357  *
 358  * If we don't have that attribute...  we still want -Wformat to work.  So,
 359  * this is the "f*ck it" approach and we just redefine int64_t to always be
 360  * <long long>.  This should work until such a time that <long long> is
 361  * something else (e.g. 128-bit integer)...  let's just guard against that
 362  * with the _Static_assert below and work with the world we have right now,
 363  * where <long long> is always 64-bit.
 364  */
 365
 366 /* these need to be included before any of the following, so we can
 367  * "overwrite" things.
 368  */
 369 #include <stdint.h>
 370 #include <inttypes.h>
 371
 372 #ifdef _FRR_ATTRIBUTE_PRINTFRR
 373 #define PRINTFRR(a, b) __attribute__((frr_format("frr_printf", a, b)))
 374
 375 #undef PRIu64
 376 #undef PRId64
 377 #undef PRIx64
 378 #define PRIu64 "Lu"
 379 #define PRId64 "Ld"
 380 #define PRIx64 "Lx"
 381
 382 #else /* !_FRR_ATTRIBUTE_PRINTFRR */
 383 #ifdef __NetBSD__
 384 #define PRINTFRR(a, b) __attribute__((format(gnu_syslog, a, b)))
 385 #else
 386 #define PRINTFRR(a, b) __attribute__((format(printf, a, b)))
 387 #endif
 388
 389 /* frr-format plugin is C-only for now, so no point in doing these shenanigans
 390  * for C++...  (also they can break some C++ stuff...)
 391  */
 392 #ifndef __cplusplus
 393 /* these should be typedefs, but might also be #define */
 394 #ifdef uint64_t
 395 #undef uint64_t
 396 #endif
 397 #ifdef int64_t
 398 #undef int64_t
 399 #endif
 400
 401 /* can't overwrite the typedef, but we can replace int64_t with _int64_t */
 402 typedef unsigned long long _uint64_t;
 403 #define uint64_t _uint64_t
 404 typedef signed long long _int64_t;
 405 #define int64_t _int64_t
 406
 407 /* if this breaks, 128-bit machines may have entered reality (or <long long>
 408  * is something weird)
 409  */
 410 _Static_assert(sizeof(_uint64_t) == 8 && sizeof(_int64_t) == 8,
 411                "nobody expects the spanish intquisition");
 412
 413 /* since we redefined int64_t, we also need to redefine PRI*64 */
 414 #undef PRIu64
 415 #undef PRId64
 416 #undef PRIx64
 417 #define PRIu64 "llu"
 418 #define PRId64 "lld"
 419 #define PRIx64 "llx"
 420
 421 #endif /* !__cplusplus */
 422 #endif /* !_FRR_ATTRIBUTE_PRINTFRR */
 423
 424 /* helper to get type safety/avoid casts on calls
 425  * (w/o this, functions accepting all prefix types need casts on the caller
 426  * side, which strips type safety since the cast will accept any pointer
 427  * type.)
 428  */
 429 #ifndef __cplusplus
 430 #define prefixtype(uname, typename, fieldname) typename *fieldname;
 431 #define TRANSPARENT_UNION __attribute__((transparent_union))
 432 #else
 433 #define prefixtype(uname, typename, fieldname)                                 \
 434         typename *fieldname;                                                   \
 435         uname(typename *x)                                                     \
 436         {                                                                      \
 437                 this->fieldname = x;                                           \
 438         }
 439 #define TRANSPARENT_UNION
 440 #endif
 441
 442 #ifdef __INTELLISENSE__
 443 /*
 444  * Fix Visual Studio Code error: argument of type "struct prefix *" is
 445  * incompatible with parameter of type "union prefixptr".
 446  *
 447  * This is caused by all functions having the transparent unions in the
 448  * prototype. Example: `prefixptr` and `prefixconstptr` from `lib/prefix.h`.
 449  */
 450 #pragma diag_suppress 167
 451 #endif /* __INTELISENSE__ */
 452
 453 #ifdef __cplusplus
 454 }
 455 #endif
 456
 457 #endif /* _FRR_COMPILER_H */