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compiler.h
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/*
* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 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
#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
#endif /* compiler.h */