100 lines
4.5 KiB
C
100 lines
4.5 KiB
C
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//
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// Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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//
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// Borrowed from
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// https://code.google.com/p/gperftools/source/browse/src/base/thread_annotations.h
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// but adapted for clang attributes instead of the gcc.
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//
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// This header file contains the macro definitions for thread safety
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// annotations that allow the developers to document the locking policies
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// of their multi-threaded code. The annotations can also help program
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// analysis tools to identify potential thread safety issues.
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#ifndef BASE_THREAD_ANNOTATIONS_H_
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#define BASE_THREAD_ANNOTATIONS_H_
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#if defined(__clang__) && (!defined(SWIG))
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#define THREAD_ANNOTATION_ATTRIBUTE__(x) __attribute__((x))
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#else
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#define THREAD_ANNOTATION_ATTRIBUTE__(x) // no-op
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#endif
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// Document if a shared variable/field needs to be protected by a lock.
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// GUARDED_BY allows the user to specify a particular lock that should be
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// held when accessing the annotated variable, while GUARDED_VAR only
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// indicates a shared variable should be guarded (by any lock). GUARDED_VAR
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// is primarily used when the client cannot express the name of the lock.
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#define GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
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#define GUARDED_VAR THREAD_ANNOTATION_ATTRIBUTE__(guarded)
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// Document if the memory location pointed to by a pointer should be guarded
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// by a lock when dereferencing the pointer. Similar to GUARDED_VAR,
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// PT_GUARDED_VAR is primarily used when the client cannot express the name
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// of the lock. Note that a pointer variable to a shared memory location
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// could itself be a shared variable. For example, if a shared global pointer
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// q, which is guarded by mu1, points to a shared memory location that is
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// guarded by mu2, q should be annotated as follows:
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// int *q GUARDED_BY(mu1) PT_GUARDED_BY(mu2);
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#define PT_GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(point_to_guarded_by(x))
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#define PT_GUARDED_VAR THREAD_ANNOTATION_ATTRIBUTE__(point_to_guarded)
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// Document the acquisition order between locks that can be held
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// simultaneously by a thread. For any two locks that need to be annotated
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// to establish an acquisition order, only one of them needs the annotation.
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// (i.e. You don't have to annotate both locks with both ACQUIRED_AFTER
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// and ACQUIRED_BEFORE.)
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#define ACQUIRED_AFTER(x) THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(x))
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#define ACQUIRED_BEFORE(x) THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(x))
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// The following three annotations document the lock requirements for
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// functions/methods.
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// Document if a function expects certain locks to be held before it is called
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#define EXCLUSIVE_LOCKS_REQUIRED(...) \
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THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(__VA_ARGS__))
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#define SHARED_LOCKS_REQUIRED(...) \
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THREAD_ANNOTATION_ATTRIBUTE__(shared_locks_required(__VA_ARGS__))
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// Document the locks acquired in the body of the function. These locks
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// cannot be held when calling this function (as google3's Mutex locks are
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// non-reentrant).
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#define LOCKS_EXCLUDED(x) THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(x))
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// Document the lock the annotated function returns without acquiring it.
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#define LOCK_RETURNED(x) THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
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// Document if a class/type is a lockable type (such as the Mutex class).
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#define LOCKABLE THREAD_ANNOTATION_ATTRIBUTE__(lockable)
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// Document if a class is a scoped lockable type (such as the MutexLock class).
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#define SCOPED_LOCKABLE THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
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// The following annotations specify lock and unlock primitives.
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#define EXCLUSIVE_LOCK_FUNCTION(...) \
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THREAD_ANNOTATION_ATTRIBUTE__(exclusive_lock_function(__VA_ARGS__))
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#define SHARED_LOCK_FUNCTION(...) \
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THREAD_ANNOTATION_ATTRIBUTE__(shared_lock_function(__VA_ARGS__))
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#define EXCLUSIVE_TRYLOCK_FUNCTION(...) \
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THREAD_ANNOTATION_ATTRIBUTE__(exclusive_trylock_function(__VA_ARGS__))
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#define SHARED_TRYLOCK_FUNCTION(...) \
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THREAD_ANNOTATION_ATTRIBUTE__(shared_trylock_function(__VA_ARGS__))
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#define UNLOCK_FUNCTION(...) \
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THREAD_ANNOTATION_ATTRIBUTE__(unlock_function(__VA_ARGS__))
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// An escape hatch for thread safety analysis to ignore the annotated function.
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#define NO_THREAD_SAFETY_ANALYSIS \
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THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
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#endif // BASE_THREAD_ANNOTATIONS_H_
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