X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fcompiler.h;h=cfe90666017bf4aeed4ab04aabb8b1c5724292dc;hb=HEAD;hp=0d7ee9f6f27c597479f1db3d4ae5371598d1fbc0;hpb=dfeb90478917b7848c89efcc6e1674f992f1ec84;p=sliver-openvswitch.git diff --git a/lib/compiler.h b/lib/compiler.h index 0d7ee9f6f..cfe906660 100644 --- a/lib/compiler.h +++ b/lib/compiler.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -17,24 +17,207 @@ #ifndef COMPILER_H #define COMPILER_H 1 +#ifndef __has_feature + #define __has_feature(x) 0 +#endif +#ifndef __has_extension + #define __has_extension(x) 0 +#endif + #if __GNUC__ && !__CHECKER__ #define NO_RETURN __attribute__((__noreturn__)) #define OVS_UNUSED __attribute__((__unused__)) #define PRINTF_FORMAT(FMT, ARG1) __attribute__((__format__(printf, FMT, ARG1))) +#define SCANF_FORMAT(FMT, ARG1) __attribute__((__format__(scanf, FMT, ARG1))) #define STRFTIME_FORMAT(FMT) __attribute__((__format__(__strftime__, FMT, 0))) #define MALLOC_LIKE __attribute__((__malloc__)) #define ALWAYS_INLINE __attribute__((always_inline)) #define WARN_UNUSED_RESULT __attribute__((__warn_unused_result__)) #define SENTINEL(N) __attribute__((sentinel(N))) +#define OVS_LIKELY(CONDITION) __builtin_expect(!!(CONDITION), 1) +#define OVS_UNLIKELY(CONDITION) __builtin_expect(!!(CONDITION), 0) #else #define NO_RETURN #define OVS_UNUSED #define PRINTF_FORMAT(FMT, ARG1) +#define SCANF_FORMAT(FMT, ARG1) #define STRFTIME_FORMAT(FMT) #define MALLOC_LIKE #define ALWAYS_INLINE #define WARN_UNUSED_RESULT #define SENTINEL(N) +#define OVS_LIKELY(CONDITION) (!!(CONDITION)) +#define OVS_UNLIKELY(CONDITION) (!!(CONDITION)) +#endif + +#if __has_feature(c_thread_safety_attributes) +/* "clang" annotations for thread safety check. + * + * OVS_LOCKABLE indicates that the struct contains mutex element + * which can be locked by functions like ovs_mutex_lock(). + * + * Below, the word MUTEX stands for the name of an object with an OVS_LOCKABLE + * struct type. It can also be a comma-separated list of multiple structs, + * e.g. to require a function to hold multiple locks while invoked. + * + * + * On a variable: + * + * - OVS_GUARDED indicates that the variable may only be accessed some mutex + * is held. + * + * - OVS_GUARDED_BY(MUTEX) indicates that the variable may only be accessed + * while the specific MUTEX is held. + * + * + * On a variable A of mutex type: + * + * - OVS_ACQ_BEFORE(B), where B is a mutex or a comma-separated list of + * mutexes, declare that if both A and B are acquired at the same time, + * then A must be acquired before B. That is, B nests inside A. + * + * - OVS_ACQ_AFTER(B) is the opposite of OVS_ACQ_BEFORE(B), that is, it + * declares that A nests inside B. + * + * + * On a function, the following attributes apply to mutexes: + * + * - OVS_ACQUIRES(MUTEX) indicate that the function must be called without + * holding MUTEX and that it returns holding MUTEX. + * + * - OVS_RELEASES(MUTEX) indicates that the function may only be called with + * MUTEX held and that it returns with MUTEX released. It can be used for + * all types of MUTEX. + * + * - OVS_TRY_LOCK(RETVAL, MUTEX) indicate that the function will try to + * acquire MUTEX. RETVAL is an integer or boolean value specifying the + * return value of a successful lock acquisition. + * + * - OVS_REQUIRES(MUTEX) indicate that the function may only be called with + * MUTEX held and that the function does not release MUTEX. + * + * - OVS_EXCLUDED(MUTEX) indicates that the function may only be called when + * MUTEX is not held. + * + * + * The following variants, with the same syntax, apply to reader-writer locks: + * + * mutex rwlock, for reading rwlock, for writing + * ------------------- ------------------- ------------------- + * OVS_ACQUIRES OVS_ACQ_RDLOCK OVS_ACQ_WRLOCK + * OVS_RELEASES OVS_RELEASES OVS_RELEASES + * OVS_TRY_LOCK OVS_TRY_RDLOCK OVS_TRY_WRLOCK + * OVS_REQUIRES OVS_REQ_RDLOCK OVS_REQ_WRLOCK + * OVS_EXCLUDED OVS_EXCLUDED OVS_EXCLUDED + */ +#define OVS_LOCKABLE __attribute__((lockable)) +#define OVS_REQ_RDLOCK(...) __attribute__((shared_locks_required(__VA_ARGS__))) +#define OVS_ACQ_RDLOCK(...) __attribute__((shared_lock_function(__VA_ARGS__))) +#define OVS_REQ_WRLOCK(...) \ + __attribute__((exclusive_locks_required(__VA_ARGS__))) +#define OVS_ACQ_WRLOCK(...) \ + __attribute__((exclusive_lock_function(__VA_ARGS__))) +#define OVS_REQUIRES(...) \ + __attribute__((exclusive_locks_required(__VA_ARGS__))) +#define OVS_ACQUIRES(...) \ + __attribute__((exclusive_lock_function(__VA_ARGS__))) +#define OVS_TRY_WRLOCK(RETVAL, ...) \ + __attribute__((exclusive_trylock_function(RETVAL, __VA_ARGS__))) +#define OVS_TRY_RDLOCK(RETVAL, ...) \ + __attribute__((shared_trylock_function(RETVAL, __VA_ARGS__))) +#define OVS_TRY_LOCK(RETVAL, ...) \ + __attribute__((exclusive_trylock_function(RETVAL, __VA_ARGS__))) +#define OVS_GUARDED __attribute__((guarded_var)) +#define OVS_GUARDED_BY(...) __attribute__((guarded_by(__VA_ARGS__))) +#define OVS_RELEASES(...) __attribute__((unlock_function(__VA_ARGS__))) +#define OVS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__))) +#define OVS_ACQ_BEFORE(...) __attribute__((acquired_before(__VA_ARGS__))) +#define OVS_ACQ_AFTER(...) __attribute__((acquired_after(__VA_ARGS__))) +#define OVS_NO_THREAD_SAFETY_ANALYSIS \ + __attribute__((no_thread_safety_analysis)) +#else /* not Clang */ +#define OVS_LOCKABLE +#define OVS_REQ_RDLOCK(...) +#define OVS_ACQ_RDLOCK(...) +#define OVS_REQ_WRLOCK(...) +#define OVS_ACQ_WRLOCK(...) +#define OVS_REQUIRES(...) +#define OVS_ACQUIRES(...) +#define OVS_TRY_WRLOCK(...) +#define OVS_TRY_RDLOCK(...) +#define OVS_TRY_LOCK(...) +#define OVS_GUARDED +#define OVS_GUARDED_BY(...) +#define OVS_EXCLUDED(...) +#define OVS_RELEASES(...) +#define OVS_ACQ_BEFORE(...) +#define OVS_ACQ_AFTER(...) +#define OVS_NO_THREAD_SAFETY_ANALYSIS +#endif + +/* ISO C says that a C implementation may choose any integer type for an enum + * that is sufficient to hold all of its values. Common ABIs (such as the + * System V ABI used on i386 GNU/Linux) always use a full-sized "int", even + * when a smaller type would suffice. + * + * In GNU C, "enum __attribute__((packed)) name { ... }" defines 'name' as an + * enum compatible with a type that is no bigger than necessary. This is the + * intended use of OVS_PACKED_ENUM. + * + * OVS_PACKED_ENUM is intended for use only as a space optimization, since it + * only works with GCC. That means that it must not be used in wire protocols + * or otherwise exposed outside of a single process. */ +#if __GNUC__ && !__CHECKER__ +#define OVS_PACKED_ENUM __attribute__((__packed__)) +#else +#define OVS_PACKED_ENUM +#endif + +#ifndef _MSC_VER +#define OVS_PACKED(DECL) DECL __attribute__((__packed__)) +#else +#define OVS_PACKED(DECL) __pragma(pack(push, 1)) DECL __pragma(pack(pop)) +#endif + +/* For defining a structure whose instances should aligned on an N-byte + * boundary. + * + * e.g. The following: + * OVS_ALIGNED_STRUCT(64, mystruct) { ... }; + * is equivalent to the following except that it specifies 64-byte alignment: + * struct mystruct { ... }; + */ +#ifndef _MSC_VER +#define OVS_ALIGNED_STRUCT(N, TAG) struct __attribute__((aligned(N))) TAG +#else +#define OVS_ALIGNED_STRUCT(N, TAG) __declspec(align(N)) struct TAG +#endif + +#ifdef _MSC_VER +#define CCALL __cdecl +#pragma section(".CRT$XCU",read) +#define OVS_CONSTRUCTOR(f) \ + static void __cdecl f(void); \ + __declspec(allocate(".CRT$XCU")) void (__cdecl*f##_)(void) = f; \ + static void __cdecl f(void) +#else +#define OVS_CONSTRUCTOR(f) \ + static void f(void) __attribute__((constructor)); \ + static void f(void) +#endif + +/* OVS_PREFETCH() can be used to instruct the CPU to fetch the cache + * line containing the given address to a CPU cache. + * OVS_PREFETCH_WRITE() should be used when the memory is going to be + * written to. Depending on the target CPU, this can generate the same + * instruction as OVS_PREFETCH(), or bring the data into the cache in an + * exclusive state. */ +#if __GNUC__ +#define OVS_PREFETCH(addr) __builtin_prefetch((addr)) +#define OVS_PREFETCH_WRITE(addr) __builtin_prefetch((addr), 1) +#else +#define OVS_PREFETCH(addr) +#define OVS_PREFETCH_WRITE(addr) #endif #endif /* compiler.h */