2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * @author Sebastian Hack
24 * @brief Some utility macros.
26 #ifndef FIRM_ADT_UTIL_H
27 #define FIRM_ADT_UTIL_H
30 * Get the offset of a member of a struct.
31 * @param type The type of the struct member is in.
32 * @param member The name of the member.
33 * @return The offset of member in type in bytes.
35 #define offset_of(type, member) \
36 ((char *) &(((type *) 0)->member) - (char *) 0)
39 * Make pointer to the struct from a pointer to a member of that struct.
40 * @param ptr The pointer to the member.
41 * @param type The type of the struct.
42 * @param member The name of the member.
43 * @return A pointer to the struct member is in.
45 #define container_of(ptr, type, member) \
46 ((type *) ((char *) (ptr) - offset_of(type, member)))
49 * Get the number of elements of a static array.
50 * @param arr The static array.
51 * @return The number of elements in that array.
53 #define array_size(arr) \
54 (sizeof(arr) / sizeof((arr)[0]))
57 * Asserts that the constant expression x is not zero at compiletime. name has
58 * to be a unique identifier.
60 * @note This uses the fact, that double case labels are not allowed.
62 #define COMPILETIME_ASSERT(x, name) \
63 static __attribute__((unused)) void compiletime_assert_##name (int h) { \
64 switch(h) { case 0: case (x): ; } \
69 * Indicates to the compiler that the value of x is very likely 1
70 * @note Only use this in speed critical code and when you are sure x is often 1
72 #define LIKELY(x) __builtin_expect((x), 1)
75 * Indicates to the compiler that it's very likely that x is 0
76 * @note Only use this in speed critical code and when you are sure x is often 0
78 #define UNLIKELY(x) __builtin_expect((x), 0)