1 #ifndef __LINUX_COMPILER_H 2 #error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead." 3 #endif 4 5 /* GCC 4.1.[01] miscompiles __weak */ 6 #ifdef __KERNEL__ 7 # if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1 8 # error Your version of gcc miscompiles the __weak directive 9 # endif 10 #endif 11 12 #define __used __attribute__((__used__)) 13 #define __must_check __attribute__((warn_unused_result)) 14 #define __compiler_offsetof(a,b) __builtin_offsetof(a,b) 15 16 #if __GNUC_MINOR__ >= 3 17 /* Mark functions as cold. gcc will assume any path leading to a call 18 to them will be unlikely. This means a lot of manual unlikely()s 19 are unnecessary now for any paths leading to the usual suspects 20 like BUG(), printk(), panic() etc. [but let's keep them for now for 21 older compilers] 22 23 Early snapshots of gcc 4.3 don't support this and we can't detect this 24 in the preprocessor, but we can live with this because they're unreleased. 25 Maketime probing would be overkill here. 26 27 gcc also has a __attribute__((__hot__)) to move hot functions into 28 a special section, but I don't see any sense in this right now in 29 the kernel context */ 30 #define __cold __attribute__((__cold__)) 31 32 33 #if __GNUC_MINOR__ >= 5 34 /* 35 * Mark a position in code as unreachable. This can be used to 36 * suppress control flow warnings after asm blocks that transfer 37 * control elsewhere. 38 * 39 * Early snapshots of gcc 4.5 don't support this and we can't detect 40 * this in the preprocessor, but we can live with this because they're 41 * unreleased. Really, we need to have autoconf for the kernel. 42 */ 43 #define unreachable() __builtin_unreachable() 44 45 /* Mark a function definition as prohibited from being cloned. */ 46 #define __noclone __attribute__((__noclone__)) 47 48 #endif 49 #endif 50 51 #if __GNUC_MINOR__ > 0 52 #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) 53 #endif 54 #if __GNUC_MINOR__ >= 4 55 #define __compiletime_warning(message) __attribute__((warning(message))) 56 #define __compiletime_error(message) __attribute__((error(message))) 57 #endif 58