lib/compiler.h

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