1 /* compiler.h: macros to abstract away compiler specifics 2 * 3 * This work is licensed under the terms of the GNU GPL, version 2 or later. 4 * See the COPYING file in the top-level directory. 5 */ 6 7 #ifndef COMPILER_H 8 #define COMPILER_H 9 10 #if defined __clang_analyzer__ || defined __COVERITY__ 11 #define QEMU_STATIC_ANALYSIS 1 12 #endif 13 14 /*---------------------------------------------------------------------------- 15 | The macro QEMU_GNUC_PREREQ tests for minimum version of the GNU C compiler. 16 | The code is a copy of SOFTFLOAT_GNUC_PREREQ, see softfloat-macros.h. 17 *----------------------------------------------------------------------------*/ 18 #if defined(__GNUC__) && defined(__GNUC_MINOR__) 19 # define QEMU_GNUC_PREREQ(maj, min) \ 20 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) 21 #else 22 # define QEMU_GNUC_PREREQ(maj, min) 0 23 #endif 24 25 #define QEMU_NORETURN __attribute__ ((__noreturn__)) 26 27 #define QEMU_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) 28 29 #define QEMU_SENTINEL __attribute__((sentinel)) 30 31 #if QEMU_GNUC_PREREQ(4, 3) 32 #define QEMU_ARTIFICIAL __attribute__((always_inline, artificial)) 33 #else 34 #define QEMU_ARTIFICIAL 35 #endif 36 37 #if defined(_WIN32) 38 # define QEMU_PACKED __attribute__((gcc_struct, packed)) 39 #else 40 # define QEMU_PACKED __attribute__((packed)) 41 #endif 42 43 #define QEMU_ALIGNED(X) __attribute__((aligned(X))) 44 45 #ifndef glue 46 #define xglue(x, y) x ## y 47 #define glue(x, y) xglue(x, y) 48 #define stringify(s) tostring(s) 49 #define tostring(s) #s 50 #endif 51 52 #ifndef likely 53 #if __GNUC__ < 3 54 #define __builtin_expect(x, n) (x) 55 #endif 56 57 #define likely(x) __builtin_expect(!!(x), 1) 58 #define unlikely(x) __builtin_expect(!!(x), 0) 59 #endif 60 61 #ifndef container_of 62 #define container_of(ptr, type, member) ({ \ 63 const typeof(((type *) 0)->member) *__mptr = (ptr); \ 64 (type *) ((char *) __mptr - offsetof(type, member));}) 65 #endif 66 67 #define sizeof_field(type, field) sizeof(((type *)0)->field) 68 69 /* Convert from a base type to a parent type, with compile time checking. */ 70 #ifdef __GNUC__ 71 #define DO_UPCAST(type, field, dev) ( __extension__ ( { \ 72 char __attribute__((unused)) offset_must_be_zero[ \ 73 -offsetof(type, field)]; \ 74 container_of(dev, type, field);})) 75 #else 76 #define DO_UPCAST(type, field, dev) container_of(dev, type, field) 77 #endif 78 79 #define typeof_field(type, field) typeof(((type *)0)->field) 80 #define type_check(t1,t2) ((t1*)0 - (t2*)0) 81 82 #define QEMU_BUILD_BUG_ON_STRUCT(x) \ 83 struct { \ 84 int:(x) ? -1 : 1; \ 85 } 86 87 /* QEMU_BUILD_BUG_MSG() emits the message given if _Static_assert is 88 * supported; otherwise, it will be omitted from the compiler error 89 * message (but as it remains present in the source code, it can still 90 * be useful when debugging). */ 91 #if defined(CONFIG_STATIC_ASSERT) 92 #define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg) 93 #elif defined(__COUNTER__) 94 #define QEMU_BUILD_BUG_MSG(x, msg) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \ 95 glue(qemu_build_bug_on__, __COUNTER__) __attribute__((unused)) 96 #else 97 #define QEMU_BUILD_BUG_MSG(x, msg) 98 #endif 99 100 #define QEMU_BUILD_BUG_ON(x) QEMU_BUILD_BUG_MSG(x, "not expecting: " #x) 101 102 #define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \ 103 sizeof(QEMU_BUILD_BUG_ON_STRUCT(x))) 104 105 #if defined __GNUC__ 106 # if !QEMU_GNUC_PREREQ(4, 4) 107 /* gcc versions before 4.4.x don't support gnu_printf, so use printf. */ 108 # define GCC_FMT_ATTR(n, m) __attribute__((format(printf, n, m))) 109 # else 110 /* Use gnu_printf when supported (qemu uses standard format strings). */ 111 # define GCC_FMT_ATTR(n, m) __attribute__((format(gnu_printf, n, m))) 112 # if defined(_WIN32) 113 /* Map __printf__ to __gnu_printf__ because we want standard format strings 114 * even when MinGW or GLib include files use __printf__. */ 115 # define __printf__ __gnu_printf__ 116 # endif 117 # endif 118 #else 119 #define GCC_FMT_ATTR(n, m) 120 #endif 121 122 #ifndef __has_feature 123 #define __has_feature(x) 0 /* compatibility with non-clang compilers */ 124 #endif 125 126 #ifndef __has_builtin 127 #define __has_builtin(x) 0 /* compatibility with non-clang compilers */ 128 #endif 129 130 #if __has_builtin(__builtin_assume_aligned) || QEMU_GNUC_PREREQ(4, 7) 131 #define HAS_ASSUME_ALIGNED 132 #endif 133 134 /* Implement C11 _Generic via GCC builtins. Example: 135 * 136 * QEMU_GENERIC(x, (float, sinf), (long double, sinl), sin) (x) 137 * 138 * The first argument is the discriminator. The last is the default value. 139 * The middle ones are tuples in "(type, expansion)" format. 140 */ 141 142 /* First, find out the number of generic cases. */ 143 #define QEMU_GENERIC(x, ...) \ 144 QEMU_GENERIC_(typeof(x), __VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) 145 146 /* There will be extra arguments, but they are not used. */ 147 #define QEMU_GENERIC_(x, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, count, ...) \ 148 QEMU_GENERIC##count(x, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) 149 150 /* Two more helper macros, this time to extract items from a parenthesized 151 * list. 152 */ 153 #define QEMU_FIRST_(a, b) a 154 #define QEMU_SECOND_(a, b) b 155 156 /* ... and a final one for the common part of the "recursion". */ 157 #define QEMU_GENERIC_IF(x, type_then, else_) \ 158 __builtin_choose_expr(__builtin_types_compatible_p(x, \ 159 QEMU_FIRST_ type_then), \ 160 QEMU_SECOND_ type_then, else_) 161 162 /* CPP poor man's "recursion". */ 163 #define QEMU_GENERIC1(x, a0, ...) (a0) 164 #define QEMU_GENERIC2(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC1(x, __VA_ARGS__)) 165 #define QEMU_GENERIC3(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC2(x, __VA_ARGS__)) 166 #define QEMU_GENERIC4(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC3(x, __VA_ARGS__)) 167 #define QEMU_GENERIC5(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC4(x, __VA_ARGS__)) 168 #define QEMU_GENERIC6(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC5(x, __VA_ARGS__)) 169 #define QEMU_GENERIC7(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC6(x, __VA_ARGS__)) 170 #define QEMU_GENERIC8(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC7(x, __VA_ARGS__)) 171 #define QEMU_GENERIC9(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC8(x, __VA_ARGS__)) 172 #define QEMU_GENERIC10(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC9(x, __VA_ARGS__)) 173 174 #endif /* COMPILER_H */ 175