macros.h revision 01e04c3f 
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)    \
76do {                        \
77   assert(!str);            \
78   __builtin_unreachable(); \
79} while (0)
80#elif defined (_MSC_VER)
81#define unreachable(str)    \
82do {                        \
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)       \
96do {                       \
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#ifdef HAVE_FUNC_ATTRIBUTE_UNUSED
234#define UNUSED __attribute__((unused))
235#else
236#define UNUSED
237#endif
238
239#define MAYBE_UNUSED UNUSED
240
241#ifdef HAVE_FUNC_ATTRIBUTE_WARN_UNUSED_RESULT
242#define MUST_CHECK __attribute__((warn_unused_result))
243#else
244#define MUST_CHECK
245#endif
246
247#if defined(__GNUC__)
248#define ATTRIBUTE_NOINLINE __attribute__((noinline))
249#else
250#define ATTRIBUTE_NOINLINE
251#endif
252
253
254/**
255 * Check that STRUCT::FIELD can hold MAXVAL.  We use a lot of bitfields
256 * in Mesa/gallium.  We have to be sure they're of sufficient size to
257 * hold the largest expected value.
258 * Note that with MSVC, enums are signed and enum bitfields need one extra
259 * high bit (always zero) to ensure the max value is handled correctly.
260 * This macro will detect that with MSVC, but not GCC.
261 */
262#define ASSERT_BITFIELD_SIZE(STRUCT, FIELD, MAXVAL) \
263   do { \
264      MAYBE_UNUSED STRUCT s;                \
265      s.FIELD = (MAXVAL); \
266      assert((int) s.FIELD == (MAXVAL) && "Insufficient bitfield size!"); \
267   } while (0)
268
269
270/** Compute ceiling of integer quotient of A divided by B. */
271#define DIV_ROUND_UP( A, B )  ( (A) % (B) == 0 ? (A)/(B) : (A)/(B)+1 )
272
273/** Clamp X to [MIN,MAX].  Turn NaN into MIN, arbitrarily. */
274#define CLAMP( X, MIN, MAX )  ( (X)>(MIN) ? ((X)>(MAX) ? (MAX) : (X)) : (MIN) )
275
276/** Minimum of two values: */
277#define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )
278
279/** Maximum of two values: */
280#define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )
281
282/** Minimum and maximum of three values: */
283#define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
284#define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
285
286/** Align a value to a power of two */
287#define ALIGN_POT(x, pot_align) (((x) + (pot_align) - 1) & ~((pot_align) - 1))
288
289/**
290 * Macro for declaring an explicit conversion operator.  Defaults to an
291 * implicit conversion if C++11 is not supported.
292 */
293#if __cplusplus >= 201103L
294#define EXPLICIT_CONVERSION explicit
295#elif defined(__cplusplus)
296#define EXPLICIT_CONVERSION
297#endif
298
299#endif /* UTIL_MACROS_H */
300