/* * 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. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #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 */