1 /* 2 * klibc/compiler.h 3 * 4 * Various compiler features 5 */ 6 7 #ifndef _KLIBC_COMPILER_H 8 #define _KLIBC_COMPILER_H 9 10 #define __user 11 12 /* Specific calling conventions */ 13 /* __cdecl is used when we want varadic and non-varadic functions to have 14 the same binary calling convention. */ 15 #ifdef __i386__ 16 # ifdef __GNUC__ 17 # define __cdecl __attribute__((cdecl,regparm(0))) 18 # else 19 /* Most other C compilers have __cdecl as a keyword */ 20 # endif 21 #else 22 # define __cdecl /* Meaningless on non-i386 */ 23 #endif 24 25 /* How to declare a function that *must* be inlined */ 26 #ifdef __GNUC__ 27 # if __GNUC_MAJOR__ >= 3 28 # define __must_inline static __inline__ __attribute__((always_inline)) 29 # else 30 # define __must_inline extern __inline__ 31 # endif 32 #else 33 # define __must_inline inline /* Just hope this works... */ 34 #endif 35 36 /* How to declare a function that does not return */ 37 #ifdef __GNUC__ 38 # define __noreturn void __attribute__((noreturn)) 39 #else 40 # define __noreturn void 41 #endif 42 43 /* "const" function: 44 45 Many functions do not examine any values except their arguments, 46 and have no effects except the return value. Basically this is 47 just slightly more strict class than the `pure' attribute above, 48 since function is not allowed to read global memory. 49 50 Note that a function that has pointer arguments and examines the 51 data pointed to must _not_ be declared `const'. Likewise, a 52 function that calls a non-`const' function usually must not be 53 `const'. It does not make sense for a `const' function to return 54 `void'. 55 */ 56 #ifdef __GNUC__ 57 # define __constfunc __attribute__((const)) 58 #else 59 # define __constfunc 60 #endif 61 #undef __attribute_const__ 62 #define __attribute_const__ __constfunc 63 64 /* "pure" function: 65 66 Many functions have no effects except the return value and their 67 return value depends only on the parameters and/or global 68 variables. Such a function can be subject to common subexpression 69 elimination and loop optimization just as an arithmetic operator 70 would be. These functions should be declared with the attribute 71 `pure'. 72 */ 73 #ifdef __GNUC__ 74 # define __purefunc __attribute__((pure)) 75 #else 76 # define __purefunc 77 #endif 78 #undef __attribute_pure__ 79 #define __attribute_pure__ __purefunc 80 81 /* Format attribute */ 82 #ifdef __GNUC__ 83 # define __formatfunc(t,f,a) __attribute__((format(t,f,a))) 84 #else 85 # define __formatfunc(t,f,a) 86 #endif 87 88 /* malloc() function (returns unaliased pointer) */ 89 #if defined(__GNUC__) && (__GNUC_MAJOR__ >= 3) 90 # define __mallocfunc __attribute__((malloc)) 91 #else 92 # define __mallocfunc 93 #endif 94 95 /* likely/unlikely */ 96 #if defined(__GNUC__) && (__GNUC_MAJOR__ > 2 || (__GNUC_MAJOR__ == 2 && __GNUC_MINOR__ >= 95)) 97 # define __likely(x) __builtin_expect(!!(x), 1) 98 # define __unlikely(x) __builtin_expect(!!(x), 0) 99 #else 100 # define __likely(x) (!!(x)) 101 # define __unlikely(x) (!!(x)) 102 #endif 103 104 /* Possibly unused function */ 105 #ifdef __GNUC__ 106 # define __unusedfunc __attribute__((unused)) 107 #else 108 # define __unusedfunc 109 #endif 110 111 /* Declare a variable or data structure as unused. */ 112 #ifdef __GNUC__ 113 # define __unused __attribute__((unused)) 114 #else 115 # define __unused 116 #endif 117 118 /* Used symbol */ 119 #define __used __attribute__((used)) 120 121 /* Constructors and destructors */ 122 #define __constructor __attribute__((constructor)) 123 #define __destructor __attribute__((destructor)) 124 125 /* Packed structures */ 126 #define __packed __attribute__((packed)) 127 128 /* Weak symbols */ 129 #define __weak __attribute__((weak)) 130 131 /* Alignment */ 132 #define __aligned(x) __attribute__((aligned(x))) 133 #define __alignas(x) __attribute__((aligned(__alignof__(x)))) 134 135 /* Handling of common (affect constructors/destructors) */ 136 #define __common __attribute__((common)) 137 #define __nocommon __attribute__((nocommon)) 138 139 /* Weak symbols */ 140 #define __weak __attribute__((weak)) 141 142 #define __export __attribute__((visibility("default"))) 143 144 #endif 145
