| 1 | /*␊ |
| 2 | * klibc/compiler.h␊ |
| 3 | *␊ |
| 4 | * Various compiler features␊ |
| 5 | */␊ |
| 6 | ␊ |
| 7 | #ifndef _KLIBC_COMPILER_H␊ |
| 8 | #define _KLIBC_COMPILER_H␊ |
| 9 | ␊ |
| 10 | /* Specific calling conventions */␊ |
| 11 | /* __cdecl is used when we want varadic and non-varadic functions to have␊ |
| 12 | the same binary calling convention. */␊ |
| 13 | #ifdef __i386__␊ |
| 14 | # ifdef __GNUC__␊ |
| 15 | # define __cdecl __attribute__((cdecl,regparm(0)))␊ |
| 16 | # else␊ |
| 17 | /* Most other C compilers have __cdecl as a keyword */␊ |
| 18 | # endif␊ |
| 19 | #else␊ |
| 20 | # define __cdecl␉␉/* Meaningless on non-i386 */␊ |
| 21 | #endif␊ |
| 22 | ␊ |
| 23 | /* How to declare a function that *must* be inlined */␊ |
| 24 | /* Use "extern inline" even in the gcc3+ case to avoid warnings in ctype.h */␊ |
| 25 | #ifdef __GNUC__␊ |
| 26 | # if __GNUC__ >= 3␊ |
| 27 | # ifdef __GNUC_STDC_INLINE__␊ |
| 28 | # define __must_inline extern __inline__ \␊ |
| 29 | ␉__attribute__((__gnu_inline__,__always_inline__))␊ |
| 30 | # else␊ |
| 31 | # define __must_inline extern __inline__ __attribute__((__always_inline__))␊ |
| 32 | # endif␊ |
| 33 | # else␊ |
| 34 | # define __must_inline extern __inline__␊ |
| 35 | # endif␊ |
| 36 | #else␊ |
| 37 | # define __must_inline inline␉/* Just hope this works... */␊ |
| 38 | #endif␊ |
| 39 | ␊ |
| 40 | /* How to declare a function that does not return */␊ |
| 41 | #ifdef __GNUC__␊ |
| 42 | # define __noreturn void __attribute__((noreturn))␊ |
| 43 | #else␊ |
| 44 | # define __noreturn void␊ |
| 45 | #endif␊ |
| 46 | ␊ |
| 47 | /* "const" function:␊ |
| 48 | ␊ |
| 49 | Many functions do not examine any values except their arguments,␊ |
| 50 | and have no effects except the return value. Basically this is␊ |
| 51 | just slightly more strict class than the `pure' attribute above,␊ |
| 52 | since function is not allowed to read global memory.␊ |
| 53 | ␊ |
| 54 | Note that a function that has pointer arguments and examines the␊ |
| 55 | data pointed to must _not_ be declared `const'. Likewise, a␊ |
| 56 | function that calls a non-`const' function usually must not be␊ |
| 57 | `const'. It does not make sense for a `const' function to return␊ |
| 58 | `void'.␊ |
| 59 | */␊ |
| 60 | #ifdef __GNUC__␊ |
| 61 | # define __constfunc __attribute__((const))␊ |
| 62 | #else␊ |
| 63 | # define __constfunc␊ |
| 64 | #endif␊ |
| 65 | #undef __attribute_const__␊ |
| 66 | #define __attribute_const__ __constfunc␊ |
| 67 | ␊ |
| 68 | /* "pure" function:␊ |
| 69 | ␊ |
| 70 | Many functions have no effects except the return value and their␊ |
| 71 | return value depends only on the parameters and/or global␊ |
| 72 | variables. Such a function can be subject to common subexpression␊ |
| 73 | elimination and loop optimization just as an arithmetic operator␊ |
| 74 | would be. These functions should be declared with the attribute␊ |
| 75 | `pure'.␊ |
| 76 | */␊ |
| 77 | #ifdef __GNUC__␊ |
| 78 | # define __purefunc __attribute__((pure))␊ |
| 79 | #else␊ |
| 80 | # define __purefunc␊ |
| 81 | #endif␊ |
| 82 | #undef __attribute_pure__␊ |
| 83 | #define __attribute_pure__ __purefunc␊ |
| 84 | ␊ |
| 85 | /* Format attribute */␊ |
| 86 | #ifdef __GNUC__␊ |
| 87 | # define __formatfunc(t,f,a) __attribute__((format(t,f,a)))␊ |
| 88 | #else␊ |
| 89 | # define __formatfunc(t,f,a)␊ |
| 90 | #endif␊ |
| 91 | ␊ |
| 92 | /* malloc() function (returns unaliased pointer) */␊ |
| 93 | #if defined(__GNUC__) && (__GNUC__ >= 3)␊ |
| 94 | # define __mallocfunc __attribute__((malloc))␊ |
| 95 | #else␊ |
| 96 | # define __mallocfunc␊ |
| 97 | #endif␊ |
| 98 | ␊ |
| 99 | /* likely/unlikely */␊ |
| 100 | #if defined(__GNUC__) && (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95))␊ |
| 101 | # define __likely(x) __builtin_expect(!!(x), 1)␊ |
| 102 | # define __unlikely(x) __builtin_expect(!!(x), 0)␊ |
| 103 | #else␊ |
| 104 | # define __likely(x) (!!(x))␊ |
| 105 | # define __unlikely(x) (!!(x))␊ |
| 106 | #endif␊ |
| 107 | ␊ |
| 108 | /* Possibly unused function */␊ |
| 109 | #ifdef __GNUC__␊ |
| 110 | # define __unusedfunc␉__attribute__((unused))␊ |
| 111 | #else␊ |
| 112 | # define __unusedfunc␊ |
| 113 | #endif␊ |
| 114 | ␊ |
| 115 | /* It's all user space... */␊ |
| 116 | #define __user␊ |
| 117 | ␊ |
| 118 | /* The bitwise attribute: disallow arithmetric operations */␊ |
| 119 | #ifdef __CHECKER__␉␉/* sparse only */␊ |
| 120 | # define __bitwise␉__attribute__((bitwise))␊ |
| 121 | #else␊ |
| 122 | # define __bitwise␊ |
| 123 | #endif␊ |
| 124 | ␊ |
| 125 | /* Shut up unused warnings */␊ |
| 126 | #ifdef __GNUC__␊ |
| 127 | # define __attribute_used__ __attribute__((used))␊ |
| 128 | #else␊ |
| 129 | # define __attribute_used__␊ |
| 130 | #endif␊ |
| 131 | ␊ |
| 132 | /* Compiler pragma to make an alias symbol */␊ |
| 133 | #define __ALIAS(__t, __f, __p, __a) \␊ |
| 134 | __t __f __p __attribute__((weak, alias(#__a)));␊ |
| 135 | ␊ |
| 136 | #endif␊ |
| 137 | |
