mirror of
https://github.com/openvswitch/ovs
synced 2025-08-22 01:51:26 +00:00
994bfc2985
This should help address a recurring problem. This change makes the OVS header files, when parsed by a C++ compiler, require C++11 or later. Signed-off-by: Ben Pfaff <blp@ovn.org> Acked-by: Russell Bryant <russell@ovn.org>
271 lines
10 KiB
C
271 lines
10 KiB
C
/*
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* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2016, 2017 Nicira, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef OPENVSWITCH_COMPILER_H
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#define OPENVSWITCH_COMPILER_H 1
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#include <stddef.h>
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#include <stdbool.h>
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#ifndef __has_feature
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#define __has_feature(x) 0
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#endif
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#ifndef __has_extension
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#define __has_extension(x) 0
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#endif
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/* To make OVS_NO_RETURN portable across gcc/clang and MSVC, it should be
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* added at the beginning of the function declaration. */
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#if __GNUC__ && !__CHECKER__
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#define OVS_NO_RETURN __attribute__((__noreturn__))
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#elif _MSC_VER
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#define OVS_NO_RETURN __declspec(noreturn)
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#else
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#define OVS_NO_RETURN
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#endif
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#if __GNUC__ && !__CHECKER__
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#define OVS_UNUSED __attribute__((__unused__))
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#define OVS_PRINTF_FORMAT(FMT, ARG1) __attribute__((__format__(printf, FMT, ARG1)))
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#define OVS_SCANF_FORMAT(FMT, ARG1) __attribute__((__format__(scanf, FMT, ARG1)))
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#define OVS_WARN_UNUSED_RESULT __attribute__((__warn_unused_result__))
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#define OVS_LIKELY(CONDITION) __builtin_expect(!!(CONDITION), 1)
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#define OVS_UNLIKELY(CONDITION) __builtin_expect(!!(CONDITION), 0)
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#else
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#define OVS_UNUSED
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#define OVS_PRINTF_FORMAT(FMT, ARG1)
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#define OVS_SCANF_FORMAT(FMT, ARG1)
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#define OVS_WARN_UNUSED_RESULT
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#define OVS_LIKELY(CONDITION) (!!(CONDITION))
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#define OVS_UNLIKELY(CONDITION) (!!(CONDITION))
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#endif
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#if __has_feature(c_thread_safety_attributes)
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/* "clang" annotations for thread safety check.
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*
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* OVS_LOCKABLE indicates that the struct contains mutex element
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* which can be locked by functions like ovs_mutex_lock().
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*
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* Below, the word MUTEX stands for the name of an object with an OVS_LOCKABLE
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* struct type. It can also be a comma-separated list of multiple structs,
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* e.g. to require a function to hold multiple locks while invoked.
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*
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*
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* On a variable:
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*
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* - OVS_GUARDED indicates that the variable may only be accessed some mutex
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* is held.
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*
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* - OVS_GUARDED_BY(MUTEX) indicates that the variable may only be accessed
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* while the specific MUTEX is held.
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*
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*
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* On a variable A of mutex type:
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*
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* - OVS_ACQ_BEFORE(B), where B is a mutex or a comma-separated list of
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* mutexes, declare that if both A and B are acquired at the same time,
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* then A must be acquired before B. That is, B nests inside A.
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*
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* - OVS_ACQ_AFTER(B) is the opposite of OVS_ACQ_BEFORE(B), that is, it
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* declares that A nests inside B.
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*
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*
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* On a function, the following attributes apply to mutexes:
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*
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* - OVS_ACQUIRES(MUTEX) indicate that the function must be called without
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* holding MUTEX and that it returns holding MUTEX.
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*
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* - OVS_RELEASES(MUTEX) indicates that the function may only be called with
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* MUTEX held and that it returns with MUTEX released. It can be used for
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* all types of MUTEX.
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*
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* - OVS_TRY_LOCK(RETVAL, MUTEX) indicate that the function will try to
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* acquire MUTEX. RETVAL is an integer or boolean value specifying the
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* return value of a successful lock acquisition.
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*
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* - OVS_REQUIRES(MUTEX) indicate that the function may only be called with
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* MUTEX held and that the function does not release MUTEX.
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*
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* - OVS_EXCLUDED(MUTEX) indicates that the function may only be called when
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* MUTEX is not held.
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*
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*
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* The following variants, with the same syntax, apply to reader-writer locks:
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*
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* mutex rwlock, for reading rwlock, for writing
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* ------------------- ------------------- -------------------
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* OVS_ACQUIRES OVS_ACQ_RDLOCK OVS_ACQ_WRLOCK
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* OVS_RELEASES OVS_RELEASES OVS_RELEASES
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* OVS_TRY_LOCK OVS_TRY_RDLOCK OVS_TRY_WRLOCK
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* OVS_REQUIRES OVS_REQ_RDLOCK OVS_REQ_WRLOCK
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* OVS_EXCLUDED OVS_EXCLUDED OVS_EXCLUDED
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*/
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#define OVS_LOCKABLE __attribute__((lockable))
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#define OVS_REQ_RDLOCK(...) __attribute__((shared_locks_required(__VA_ARGS__)))
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#define OVS_ACQ_RDLOCK(...) __attribute__((shared_lock_function(__VA_ARGS__)))
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#define OVS_REQ_WRLOCK(...) \
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__attribute__((exclusive_locks_required(__VA_ARGS__)))
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#define OVS_ACQ_WRLOCK(...) \
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__attribute__((exclusive_lock_function(__VA_ARGS__)))
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#define OVS_REQUIRES(...) \
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__attribute__((exclusive_locks_required(__VA_ARGS__)))
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#define OVS_ACQUIRES(...) \
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__attribute__((exclusive_lock_function(__VA_ARGS__)))
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#define OVS_TRY_WRLOCK(RETVAL, ...) \
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__attribute__((exclusive_trylock_function(RETVAL, __VA_ARGS__)))
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#define OVS_TRY_RDLOCK(RETVAL, ...) \
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__attribute__((shared_trylock_function(RETVAL, __VA_ARGS__)))
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#define OVS_TRY_LOCK(RETVAL, ...) \
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__attribute__((exclusive_trylock_function(RETVAL, __VA_ARGS__)))
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#define OVS_GUARDED __attribute__((guarded_var))
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#define OVS_GUARDED_BY(...) __attribute__((guarded_by(__VA_ARGS__)))
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#define OVS_RELEASES(...) __attribute__((unlock_function(__VA_ARGS__)))
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#define OVS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__)))
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#define OVS_ACQ_BEFORE(...) __attribute__((acquired_before(__VA_ARGS__)))
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#define OVS_ACQ_AFTER(...) __attribute__((acquired_after(__VA_ARGS__)))
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#define OVS_NO_THREAD_SAFETY_ANALYSIS \
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__attribute__((no_thread_safety_analysis))
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#else /* not Clang */
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#define OVS_LOCKABLE
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#define OVS_REQ_RDLOCK(...)
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#define OVS_ACQ_RDLOCK(...)
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#define OVS_REQ_WRLOCK(...)
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#define OVS_ACQ_WRLOCK(...)
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#define OVS_REQUIRES(...)
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#define OVS_ACQUIRES(...)
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#define OVS_TRY_WRLOCK(...)
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#define OVS_TRY_RDLOCK(...)
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#define OVS_TRY_LOCK(...)
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#define OVS_GUARDED
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#define OVS_GUARDED_BY(...)
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#define OVS_EXCLUDED(...)
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#define OVS_RELEASES(...)
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#define OVS_ACQ_BEFORE(...)
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#define OVS_ACQ_AFTER(...)
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#define OVS_NO_THREAD_SAFETY_ANALYSIS
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#endif
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/* ISO C says that a C implementation may choose any integer type for an enum
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* that is sufficient to hold all of its values. Common ABIs (such as the
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* System V ABI used on i386 GNU/Linux) always use a full-sized "int", even
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* when a smaller type would suffice.
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*
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* In GNU C, "enum __attribute__((packed)) name { ... }" defines 'name' as an
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* enum compatible with a type that is no bigger than necessary. This is the
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* intended use of OVS_PACKED_ENUM.
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*
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* OVS_PACKED_ENUM is intended for use only as a space optimization, since it
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* only works with GCC. That means that it must not be used in wire protocols
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* or otherwise exposed outside of a single process. */
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#if __GNUC__ && !__CHECKER__
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#define OVS_PACKED_ENUM __attribute__((__packed__))
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#define HAVE_PACKED_ENUM
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#else
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#define OVS_PACKED_ENUM
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#endif
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#ifndef _MSC_VER
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#define OVS_PACKED(DECL) DECL __attribute__((__packed__))
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#else
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#define OVS_PACKED(DECL) __pragma(pack(push, 1)) DECL __pragma(pack(pop))
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#endif
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/* OVS_ALIGNED_STRUCT may be used to define a structure whose instances should
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* aligned on an N-byte boundary. This:
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* OVS_ALIGNED_STRUCT(64, mystruct) { ... };
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* is equivalent to the following except that it specifies 64-byte alignment:
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* struct mystruct { ... };
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*
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* OVS_ALIGNED_VAR defines a variable aligned on an N-byte boundary. For
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* example,
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* OVS_ALIGNED_VAR(64) int x;
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* defines a "int" variable that is aligned on a 64-byte boundary.
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*/
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#ifndef _MSC_VER
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#define OVS_ALIGNED_STRUCT(N, TAG) struct __attribute__((aligned(N))) TAG
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#define OVS_ALIGNED_VAR(N) __attribute__((aligned(N)))
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#else
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#define OVS_ALIGNED_STRUCT(N, TAG) __declspec(align(N)) struct TAG
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#define OVS_ALIGNED_VAR(N) __declspec(align(N))
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#endif
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/* Supplies code to be run at startup time before invoking main().
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* Use as:
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*
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* OVS_CONSTRUCTOR(my_constructor) {
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* ...some code...
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* }
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*/
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#ifdef _MSC_VER
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#define CCALL __cdecl
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#pragma section(".CRT$XCU",read)
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#define OVS_CONSTRUCTOR(f) \
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static void __cdecl f(void); \
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__declspec(allocate(".CRT$XCU")) static void (__cdecl*f##_)(void) = f; \
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static void __cdecl f(void)
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#else
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#define OVS_CONSTRUCTOR(f) \
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static void f(void) __attribute__((constructor)); \
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static void f(void)
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#endif
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/* OVS_PREFETCH() can be used to instruct the CPU to fetch the cache
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* line containing the given address to a CPU cache.
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* OVS_PREFETCH_WRITE() should be used when the memory is going to be
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* written to. Depending on the target CPU, this can generate the same
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* instruction as OVS_PREFETCH(), or bring the data into the cache in an
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* exclusive state. */
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#if __GNUC__
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#define OVS_PREFETCH(addr) __builtin_prefetch((addr))
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#define OVS_PREFETCH_WRITE(addr) __builtin_prefetch((addr), 1)
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#else
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#define OVS_PREFETCH(addr)
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#define OVS_PREFETCH_WRITE(addr)
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#endif
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/* Build assertions.
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*
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* Use BUILD_ASSERT_DECL as a declaration or a statement, or BUILD_ASSERT as
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* part of an expression. */
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#ifdef __CHECKER__
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#define BUILD_ASSERT(EXPR) ((void) 0)
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#define BUILD_ASSERT_DECL(EXPR) extern int (*build_assert(void))[1]
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#elif defined(__cplusplus)
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#define BUILD_ASSERT(EXPR) static_assert(EXPR, "assertion failed")
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#define BUILD_ASSERT_DECL(EXPR) static_assert(EXPR, "assertion failed")
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#elif (__GNUC__ * 256 + __GNUC_MINOR__ >= 0x403 \
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|| __has_extension(c_static_assert))
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#define BUILD_ASSERT_DECL(EXPR) _Static_assert(EXPR, #EXPR)
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#define BUILD_ASSERT(EXPR) (void) ({ _Static_assert(EXPR, #EXPR); })
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#else
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#define BUILD_ASSERT__(EXPR) \
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sizeof(struct { unsigned int build_assert_failed : (EXPR) ? 1 : -1; })
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#define BUILD_ASSERT(EXPR) (void) BUILD_ASSERT__(EXPR)
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#define BUILD_ASSERT_DECL(EXPR) \
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extern int (*build_assert(void))[BUILD_ASSERT__(EXPR)]
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#endif
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#ifdef __GNUC__
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#define BUILD_ASSERT_GCCONLY(EXPR) BUILD_ASSERT(EXPR)
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#define BUILD_ASSERT_DECL_GCCONLY(EXPR) BUILD_ASSERT_DECL(EXPR)
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#else
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#define BUILD_ASSERT_GCCONLY(EXPR) ((void) 0)
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#define BUILD_ASSERT_DECL_GCCONLY(EXPR) ((void) 0)
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#endif
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#endif /* compiler.h */
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