src/util/macros.h

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #ifndef UTIL_MACROS_H
  25 #define UTIL_MACROS_H
  26
  27 #include <assert.h>
  28
  29 #include "c99_compat.h"
  30
  31 /* Compute the size of an array */
  32 #ifndef ARRAY_SIZE
  33 #  define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  34 #endif
  35
  36 /* For compatibility with Clang's __has_builtin() */
  37 #ifndef __has_builtin
  38 #  define __has_builtin(x) 0
  39 #endif
  40
  41 /**
  42  * __builtin_expect macros
  43  */
  44 #if !defined(HAVE___BUILTIN_EXPECT)
  45 #  define __builtin_expect(x, y) (x)
  46 #endif
  47
  48 #ifndef likely
  49 #  ifdef HAVE___BUILTIN_EXPECT
  50 #    define likely(x)   __builtin_expect(!!(x), 1)
  51 #    define unlikely(x) __builtin_expect(!!(x), 0)
  52 #  else
  53 #    define likely(x)   (x)
  54 #    define unlikely(x) (x)
  55 #  endif
  56 #endif
  57
  58
  59 /**
  60  * Static (compile-time) assertion.
  61  * Basically, use COND to dimension an array.  If COND is false/zero the
  62  * array size will be -1 and we'll get a compilation error.
  63  */
  64 #define STATIC_ASSERT(COND) \
  65    do { \
  66       (void) sizeof(char [1 - 2*!(COND)]); \
  67    } while (0)
  68
  69
  70 /**
  71  * Unreachable macro. Useful for suppressing "control reaches end of non-void
  72  * function" warnings.
  73  */
  74 #ifdef HAVE___BUILTIN_UNREACHABLE
  75 #define unreachable(str)    \
  76 do {                        \
  77    assert(!str);            \
  78    __builtin_unreachable(); \
  79 } while (0)
  80 #elif defined (_MSC_VER)
  81 #define unreachable(str)    \
  82 do {                        \
  83    assert(!str);            \
  84    __assume(0);             \
  85 } while (0)
  86 #else
  87 #define unreachable(str) assert(!str)
  88 #endif
  89
  90 /**
  91  * Assume macro. Useful for expressing our assumptions to the compiler,
  92  * typically for purposes of silencing warnings.
  93  */
  94 #if __has_builtin(__builtin_assume)
  95 #define assume(expr)       \
  96 do {                       \
  97    assert(expr);           \
  98    __builtin_assume(expr); \
  99 } while (0)
 100 #elif defined HAVE___BUILTIN_UNREACHABLE
 101 #define assume(expr) ((expr) ? ((void) 0) \
 102                              : (assert(!"assumption failed"), \
 103                                 __builtin_unreachable()))
 104 #elif defined (_MSC_VER)
 105 #define assume(expr) __assume(expr)
 106 #else
 107 #define assume(expr) assert(expr)
 108 #endif
 109
 110 /* Attribute const is used for functions that have no effects other than their
 111  * return value, and only rely on the argument values to compute the return
 112  * value.  As a result, calls to it can be CSEed.  Note that using memory
 113  * pointed to by the arguments is not allowed for const functions.
 114  */
 115 #ifdef HAVE_FUNC_ATTRIBUTE_CONST
 116 #define ATTRIBUTE_CONST __attribute__((__const__))
 117 #else
 118 #define ATTRIBUTE_CONST
 119 #endif
 120
 121 #ifdef HAVE_FUNC_ATTRIBUTE_FLATTEN
 122 #define FLATTEN __attribute__((__flatten__))
 123 #else
 124 #define FLATTEN
 125 #endif
 126
 127 #ifdef HAVE_FUNC_ATTRIBUTE_FORMAT
 128 #define PRINTFLIKE(f, a) __attribute__ ((format(__printf__, f, a)))
 129 #else
 130 #define PRINTFLIKE(f, a)
 131 #endif
 132
 133 #ifdef HAVE_FUNC_ATTRIBUTE_MALLOC
 134 #define MALLOCLIKE __attribute__((__malloc__))
 135 #else
 136 #define MALLOCLIKE
 137 #endif
 138
 139 /* Forced function inlining */
 140 /* Note: Clang also sets __GNUC__ (see other cases below) */
 141 #ifndef ALWAYS_INLINE
 142 #  if defined(__GNUC__)
 143 #    define ALWAYS_INLINE inline __attribute__((always_inline))
 144 #  elif defined(_MSC_VER)
 145 #    define ALWAYS_INLINE __forceinline
 146 #  else
 147 #    define ALWAYS_INLINE inline
 148 #  endif
 149 #endif
 150
 151 /* Used to optionally mark structures with misaligned elements or size as
 152  * packed, to trade off performance for space.
 153  */
 154 #ifdef HAVE_FUNC_ATTRIBUTE_PACKED
 155 #define PACKED __attribute__((__packed__))
 156 #else
 157 #define PACKED
 158 #endif
 159
 160 /* Attribute pure is used for functions that have no effects other than their
 161  * return value.  As a result, calls to it can be dead code eliminated.
 162  */
 163 #ifdef HAVE_FUNC_ATTRIBUTE_PURE
 164 #define ATTRIBUTE_PURE __attribute__((__pure__))
 165 #else
 166 #define ATTRIBUTE_PURE
 167 #endif
 168
 169 #ifdef HAVE_FUNC_ATTRIBUTE_RETURNS_NONNULL
 170 #define ATTRIBUTE_RETURNS_NONNULL __attribute__((__returns_nonnull__))
 171 #else
 172 #define ATTRIBUTE_RETURNS_NONNULL
 173 #endif
 174
 175 #ifndef NORETURN
 176 #  ifdef _MSC_VER
 177 #    define NORETURN __declspec(noreturn)
 178 #  elif defined HAVE_FUNC_ATTRIBUTE_NORETURN
 179 #    define NORETURN __attribute__((__noreturn__))
 180 #  else
 181 #    define NORETURN
 182 #  endif
 183 #endif
 184
 185 #ifdef __cplusplus
 186 /**
 187  * Macro function that evaluates to true if T is a trivially
 188  * destructible type -- that is, if its (non-virtual) destructor
 189  * performs no action and all member variables and base classes are
 190  * trivially destructible themselves.
 191  */
 192 #   if (defined(__clang__) && defined(__has_feature))
 193 #      if __has_feature(has_trivial_destructor)
 194 #         define HAS_TRIVIAL_DESTRUCTOR(T) __has_trivial_destructor(T)
 195 #      endif
 196 #   elif defined(__GNUC__)
 197 #      if ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)))
 198 #         define HAS_TRIVIAL_DESTRUCTOR(T) __has_trivial_destructor(T)
 199 #      endif
 200 #   elif defined(_MSC_VER) && !defined(__INTEL_COMPILER)
 201 #      define HAS_TRIVIAL_DESTRUCTOR(T) __has_trivial_destructor(T)
 202 #   endif
 203 #   ifndef HAS_TRIVIAL_DESTRUCTOR
 204        /* It's always safe (if inefficient) to assume that a
 205         * destructor is non-trivial.
 206         */
 207 #      define HAS_TRIVIAL_DESTRUCTOR(T) (false)
 208 #   endif
 209 #endif
 210
 211 /**
 212  * PUBLIC/USED macros
 213  *
 214  * If we build the library with gcc's -fvisibility=hidden flag, we'll
 215  * use the PUBLIC macro to mark functions that are to be exported.
 216  *
 217  * We also need to define a USED attribute, so the optimizer doesn't
 218  * inline a static function that we later use in an alias. - ajax
 219  */
 220 #ifndef PUBLIC
 221 #  if defined(__GNUC__)
 222 #    define PUBLIC __attribute__((visibility("default")))
 223 #    define USED __attribute__((used))
 224 #  elif defined(_MSC_VER)
 225 #    define PUBLIC __declspec(dllexport)
 226 #    define USED
 227 #  else
 228 #    define PUBLIC
 229 #    define USED
 230 #  endif
 231 #endif
 232
 233 /**
 234  * UNUSED marks variables (or sometimes functions) that have to be defined,
 235  * but are sometimes (or always) unused beyond that. A common case is for
 236  * a function parameter to be used in some build configurations but not others.
 237  * Another case is fallback vfuncs that don't do anything with their params.
 238  *
 239  * Note that this should not be used for identifiers used in `assert()`;
 240  * see ASSERTED below.
 241  */
 242 #ifdef HAVE_FUNC_ATTRIBUTE_UNUSED
 243 #define UNUSED __attribute__((unused))
 244 #else
 245 #define UNUSED
 246 #endif
 247
 248 /**
 249  * Use ASSERTED to indicate that an identifier is unused outside of an `assert()`,
 250  * so that assert-free builds don't get "unused variable" warnings.
 251  */
 252 #ifdef NDEBUG
 253 #define ASSERTED UNUSED
 254 #else
 255 #define ASSERTED
 256 #endif
 257
 258 #ifdef HAVE_FUNC_ATTRIBUTE_WARN_UNUSED_RESULT
 259 #define MUST_CHECK __attribute__((warn_unused_result))
 260 #else
 261 #define MUST_CHECK
 262 #endif
 263
 264 #if defined(__GNUC__)
 265 #define ATTRIBUTE_NOINLINE __attribute__((noinline))
 266 #else
 267 #define ATTRIBUTE_NOINLINE
 268 #endif
 269
 270
 271 /**
 272  * Check that STRUCT::FIELD can hold MAXVAL.  We use a lot of bitfields
 273  * in Mesa/gallium.  We have to be sure they're of sufficient size to
 274  * hold the largest expected value.
 275  * Note that with MSVC, enums are signed and enum bitfields need one extra
 276  * high bit (always zero) to ensure the max value is handled correctly.
 277  * This macro will detect that with MSVC, but not GCC.
 278  */
 279 #define ASSERT_BITFIELD_SIZE(STRUCT, FIELD, MAXVAL) \
 280    do { \
 281       ASSERTED STRUCT s; \
 282       s.FIELD = (MAXVAL); \
 283       assert((int) s.FIELD == (MAXVAL) && "Insufficient bitfield size!"); \
 284    } while (0)
 285
 286
 287 /** Compute ceiling of integer quotient of A divided by B. */
 288 #define DIV_ROUND_UP( A, B )  ( ((A) + (B) - 1) / (B) )
 289
 290 /** Clamp X to [MIN,MAX].  Turn NaN into MIN, arbitrarily. */
 291 #define CLAMP( X, MIN, MAX )  ( (X)>(MIN) ? ((X)>(MAX) ? (MAX) : (X)) : (MIN) )
 292
 293 /** Minimum of two values: */
 294 #define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )
 295
 296 /** Maximum of two values: */
 297 #define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )
 298
 299 /** Minimum and maximum of three values: */
 300 #define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
 301 #define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
 302
 303 /** Align a value to a power of two */
 304 #define ALIGN_POT(x, pot_align) (((x) + (pot_align) - 1) & ~((pot_align) - 1))
 305
 306 /**
 307  * Macro for declaring an explicit conversion operator.  Defaults to an
 308  * implicit conversion if C++11 is not supported.
 309  */
 310 #if __cplusplus >= 201103L
 311 #define EXPLICIT_CONVERSION explicit
 312 #elif defined(__cplusplus)
 313 #define EXPLICIT_CONVERSION
 314 #endif
 315
 316 /** Set a single bit */
 317 #define BITFIELD_BIT(b)      (1u << (b))
 318 /** Set all bits up to excluding bit b */
 319 #define BITFIELD_MASK(b)      \
 320    ((b) == 32 ? (~0u) : BITFIELD_BIT((b) % 32) - 1)
 321 /** Set count bits starting from bit b  */
 322 #define BITFIELD_RANGE(b, count) \
 323    (BITFIELD_MASK((b) + (count)) & ~BITFIELD_MASK(b))
 324
 325 /** Set a single bit */
 326 #define BITFIELD64_BIT(b)      (1ull << (b))
 327 /** Set all bits up to excluding bit b */
 328 #define BITFIELD64_MASK(b)      \
 329    ((b) == 64 ? (~0ull) : BITFIELD64_BIT(b) - 1)
 330 /** Set count bits starting from bit b  */
 331 #define BITFIELD64_RANGE(b, count) \
 332    (BITFIELD64_MASK((b) + (count)) & ~BITFIELD64_MASK(b))
 333
 334 #endif /* UTIL_MACROS_H */