#ifndef __LINUX_COMPILER_H #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead." #endif /* * Common definitions for all gcc versions go here. */ /* Optimization barrier */ /* The "volatile" is due to gcc bugs */ #define barrier() __asm__ __volatile__("": : :"memory") /* * This macro obfuscates arithmetic on a variable address so that gcc * shouldn't recognize the original var, and make assumptions about it. * * This is needed because the C standard makes it undefined to do * pointer arithmetic on "objects" outside their boundaries and the * gcc optimizers assume this is the case. In particular they * assume such arithmetic does not wrap. * * A miscompilation has been observed because of this on PPC. * To work around it we hide the relationship of the pointer and the object * using this macro. * * Versions of the ppc64 compiler before 4.1 had a bug where use of * RELOC_HIDE could trash r30. The bug can be worked around by changing * the inline assembly constraint from =g to =r, in this particular * case either is valid. */ #define RELOC_HIDE(ptr, off) \ ({ unsigned long __ptr; \ __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ (typeof(ptr)) (__ptr + (off)); }) /* &a[0] degrades to a pointer: a different type from an array */ #define __must_be_array(a) \ BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0]))) /* * Force always-inline if the user requests it so via the .config, * or if gcc is too old: */ #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) # define inline inline __attribute__((always_inline)) # define __inline__ __inline__ __attribute__((always_inline)) # define __inline __inline __attribute__((always_inline)) #endif #define __deprecated __attribute__((deprecated)) #define __packed __attribute__((packed)) #define __weak __attribute__((weak)) /* * it doesn't make sense on ARM (currently the only user of __naked) to trace * naked functions because then mcount is called without stack and frame pointer * being set up and there is no chance to restore the lr register to the value * before mcount was called. */ #define __naked __attribute__((naked)) notrace #define __noreturn __attribute__((noreturn)) /* * From the GCC manual: * * Many functions have no effects except the return value and their * return value depends only on the parameters and/or global * variables. Such a function can be subject to common subexpression * elimination and loop optimization just as an arithmetic operator * would be. * [...] */ #define __pure __attribute__((pure)) #define __aligned(x) __attribute__((aligned(x))) #define __printf(a,b) __attribute__((format(printf,a,b))) #define noinline __attribute__((noinline)) #define __attribute_const__ __attribute__((__const__)) #define __maybe_unused __attribute__((unused)) #define __always_unused __attribute__((unused)) #define __gcc_header(x) #x #define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h) #define gcc_header(x) _gcc_header(x) #include gcc_header(__GNUC__)