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 #define HOST_BIG_ENDIAN (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) 11 12 /* HOST_LONG_BITS is the size of a native pointer in bits. */ 13 #define HOST_LONG_BITS (__SIZEOF_POINTER__ * 8) 14 15 #if defined __clang_analyzer__ || defined __COVERITY__ 16 #define QEMU_STATIC_ANALYSIS 1 17 #endif 18 19 #ifdef __cplusplus 20 #define QEMU_EXTERN_C extern "C" 21 #else 22 #define QEMU_EXTERN_C extern 23 #endif 24 25 #if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__)) 26 # define QEMU_PACKED __attribute__((gcc_struct, packed)) 27 #else 28 # define QEMU_PACKED __attribute__((packed)) 29 #endif 30 31 #define QEMU_ALIGNED(X) __attribute__((aligned(X))) 32 33 #ifndef glue 34 #define xglue(x, y) x ## y 35 #define glue(x, y) xglue(x, y) 36 #define stringify(s) tostring(s) 37 #define tostring(s) #s 38 #endif 39 40 #ifndef likely 41 #define likely(x) __builtin_expect(!!(x), 1) 42 #define unlikely(x) __builtin_expect(!!(x), 0) 43 #endif 44 45 #ifndef container_of 46 #define container_of(ptr, type, member) ({ \ 47 const typeof(((type *) 0)->member) *__mptr = (ptr); \ 48 (type *) ((char *) __mptr - offsetof(type, member));}) 49 #endif 50 51 #define sizeof_field(type, field) sizeof(((type *)0)->field) 52 53 /* 54 * Calculate the number of bytes up to and including the given 'field' of 55 * 'container'. 56 */ 57 #define endof(container, field) \ 58 (offsetof(container, field) + sizeof_field(container, field)) 59 60 /* Convert from a base type to a parent type, with compile time checking. */ 61 #define DO_UPCAST(type, field, dev) ( __extension__ ( { \ 62 char __attribute__((unused)) offset_must_be_zero[ \ 63 -offsetof(type, field)]; \ 64 container_of(dev, type, field);})) 65 66 #define typeof_field(type, field) typeof(((type *)0)->field) 67 #define type_check(t1,t2) ((t1*)0 - (t2*)0) 68 69 #define QEMU_BUILD_BUG_ON_STRUCT(x) \ 70 struct { \ 71 int:(x) ? -1 : 1; \ 72 } 73 74 #define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg) 75 76 #define QEMU_BUILD_BUG_ON(x) QEMU_BUILD_BUG_MSG(x, "not expecting: " #x) 77 78 #define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \ 79 sizeof(QEMU_BUILD_BUG_ON_STRUCT(x))) 80 81 #if !defined(__clang__) && defined(_WIN32) 82 /* 83 * Map __printf__ to __gnu_printf__ because we want standard format strings even 84 * when MinGW or GLib include files use __printf__. 85 */ 86 # define __printf__ __gnu_printf__ 87 #endif 88 89 #ifndef __has_warning 90 #define __has_warning(x) 0 /* compatibility with non-clang compilers */ 91 #endif 92 93 #ifndef __has_feature 94 #define __has_feature(x) 0 /* compatibility with non-clang compilers */ 95 #endif 96 97 #ifndef __has_builtin 98 #define __has_builtin(x) 0 /* compatibility with non-clang compilers */ 99 #endif 100 101 #if __has_builtin(__builtin_assume_aligned) || !defined(__clang__) 102 #define HAS_ASSUME_ALIGNED 103 #endif 104 105 #ifndef __has_attribute 106 #define __has_attribute(x) 0 /* compatibility with older GCC */ 107 #endif 108 109 #if defined(__SANITIZE_ADDRESS__) || __has_feature(address_sanitizer) 110 # define QEMU_SANITIZE_ADDRESS 1 111 #endif 112 113 #if defined(__SANITIZE_THREAD__) || __has_feature(thread_sanitizer) 114 # define QEMU_SANITIZE_THREAD 1 115 #endif 116 117 /* 118 * GCC doesn't provide __has_attribute() until GCC 5, but we know all the GCC 119 * versions we support have the "flatten" attribute. Clang may not have the 120 * "flatten" attribute but always has __has_attribute() to check for it. 121 */ 122 #if __has_attribute(flatten) || !defined(__clang__) 123 # define QEMU_FLATTEN __attribute__((flatten)) 124 #else 125 # define QEMU_FLATTEN 126 #endif 127 128 /* 129 * If __attribute__((error)) is present, use it to produce an error at 130 * compile time. Otherwise, one must wait for the linker to diagnose 131 * the missing symbol. 132 */ 133 #if __has_attribute(error) 134 # define QEMU_ERROR(X) __attribute__((error(X))) 135 #else 136 # define QEMU_ERROR(X) 137 #endif 138 139 /* 140 * The nonstring variable attribute specifies that an object or member 141 * declaration with type array of char or pointer to char is intended 142 * to store character arrays that do not necessarily contain a terminating 143 * NUL character. This is useful in detecting uses of such arrays or pointers 144 * with functions that expect NUL-terminated strings, and to avoid warnings 145 * when such an array or pointer is used as an argument to a bounded string 146 * manipulation function such as strncpy. 147 */ 148 #if __has_attribute(nonstring) 149 # define QEMU_NONSTRING __attribute__((nonstring)) 150 #else 151 # define QEMU_NONSTRING 152 #endif 153 154 /* 155 * Forced inlining may be desired to encourage constant propagation 156 * of function parameters. However, it can also make debugging harder, 157 * so disable it for a non-optimizing build. 158 */ 159 #if defined(__OPTIMIZE__) 160 #define QEMU_ALWAYS_INLINE __attribute__((always_inline)) 161 #else 162 #define QEMU_ALWAYS_INLINE 163 #endif 164 165 /** 166 * In most cases, normal "fallthrough" comments are good enough for 167 * switch-case statements, but sometimes the compiler has problems 168 * with those. In that case you can use QEMU_FALLTHROUGH instead. 169 */ 170 #if __has_attribute(fallthrough) 171 # define QEMU_FALLTHROUGH __attribute__((fallthrough)) 172 #else 173 # define QEMU_FALLTHROUGH do {} while (0) /* fallthrough */ 174 #endif 175 176 #ifdef CONFIG_CFI 177 /* 178 * If CFI is enabled, use an attribute to disable cfi-icall on the following 179 * function 180 */ 181 #define QEMU_DISABLE_CFI __attribute__((no_sanitize("cfi-icall"))) 182 #else 183 /* If CFI is not enabled, use an empty define to not change the behavior */ 184 #define QEMU_DISABLE_CFI 185 #endif 186 187 #endif /* COMPILER_H */ 188