1 #ifndef __LINUX_COMPILER_H 2 #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." 3 #endif 4 5 /* 6 * Common definitions for all gcc versions go here. 7 */ 8 9 10 /* Optimization barrier */ 11 /* The "volatile" is due to gcc bugs */ 12 #define barrier() __asm__ __volatile__("": : :"memory") 13 14 /* This macro obfuscates arithmetic on a variable address so that gcc 15 shouldn't recognize the original var, and make assumptions about it */ 16 /* 17 * Versions of the ppc64 compiler before 4.1 had a bug where use of 18 * RELOC_HIDE could trash r30. The bug can be worked around by changing 19 * the inline assembly constraint from =g to =r, in this particular 20 * case either is valid. 21 */ 22 #define RELOC_HIDE(ptr, off) \ 23 ({ unsigned long __ptr; \ 24 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ 25 (typeof(ptr)) (__ptr + (off)); }) 26 27 /* &a[0] degrades to a pointer: a different type from an array */ 28 #define __must_be_array(a) \ 29 BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0]))) 30 31 /* 32 * Force always-inline if the user requests it so via the .config, 33 * or if gcc is too old: 34 */ 35 #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ 36 !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) 37 # define inline inline __attribute__((always_inline)) 38 # define __inline__ __inline__ __attribute__((always_inline)) 39 # define __inline __inline __attribute__((always_inline)) 40 #endif 41 42 #define __deprecated __attribute__((deprecated)) 43 #define __packed __attribute__((packed)) 44 #define __weak __attribute__((weak)) 45 #define __naked __attribute__((naked)) 46 #define __noreturn __attribute__((noreturn)) 47 48 /* 49 * From the GCC manual: 50 * 51 * Many functions have no effects except the return value and their 52 * return value depends only on the parameters and/or global 53 * variables. Such a function can be subject to common subexpression 54 * elimination and loop optimization just as an arithmetic operator 55 * would be. 56 * [...] 57 */ 58 #define __pure __attribute__((pure)) 59 #define __aligned(x) __attribute__((aligned(x))) 60 #define __printf(a,b) __attribute__((format(printf,a,b))) 61 #define noinline __attribute__((noinline)) 62 #define __attribute_const__ __attribute__((__const__)) 63 #define __maybe_unused __attribute__((unused)) 64