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andresp@webrtc.org7fb75ec2013-12-20 20:20:501//
2// Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
3//
4// Use of this source code is governed by a BSD-style license
5// that can be found in the LICENSE file in the root of the source
6// tree. An additional intellectual property rights grant can be found
7// in the file PATENTS. All contributing project authors may
8// be found in the AUTHORS file in the root of the source tree.
9//
10// Borrowed from
11// https://code.google.com/p/gperftools/source/browse/src/base/thread_annotations.h
12// but adapted for clang attributes instead of the gcc.
13//
14// This header file contains the macro definitions for thread safety
15// annotations that allow the developers to document the locking policies
16// of their multi-threaded code. The annotations can also help program
17// analysis tools to identify potential thread safety issues.
18
Mirko Bonadei92ea95e2017-09-15 04:47:3119#ifndef RTC_BASE_THREAD_ANNOTATIONS_H_
20#define RTC_BASE_THREAD_ANNOTATIONS_H_
andresp@webrtc.org7fb75ec2013-12-20 20:20:5021
Henrik Kjellanderec78f1c2017-06-29 05:52:5022#if defined(__clang__) && (!defined(SWIG))
danilchap5301e3c2017-09-06 11:10:2123#define RTC_THREAD_ANNOTATION_ATTRIBUTE__(x) __attribute__((x))
Henrik Kjellanderec78f1c2017-06-29 05:52:5024#else
danilchap5301e3c2017-09-06 11:10:2125#define RTC_THREAD_ANNOTATION_ATTRIBUTE__(x) // no-op
Henrik Kjellanderec78f1c2017-06-29 05:52:5026#endif
andresp@webrtc.org7fb75ec2013-12-20 20:20:5027
Henrik Kjellanderec78f1c2017-06-29 05:52:5028// Document if a shared variable/field needs to be protected by a lock.
29// GUARDED_BY allows the user to specify a particular lock that should be
Danil Chapovalov37651992017-11-01 09:52:0930// held when accessing the annotated variable.
danilchap5301e3c2017-09-06 11:10:2131#define RTC_GUARDED_BY(x) RTC_THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
Henrik Kjellanderec78f1c2017-06-29 05:52:5032
33// Document if the memory location pointed to by a pointer should be guarded
Danil Chapovalov37651992017-11-01 09:52:0934// by a lock when dereferencing the pointer. Note that a pointer variable to a
35// shared memory location could itself be a shared variable. For example, if a
36// shared global pointer q, which is guarded by mu1, points to a shared memory
37// location that is guarded by mu2, q should be annotated as follows:
Henrik Kjellanderec78f1c2017-06-29 05:52:5038// int *q GUARDED_BY(mu1) PT_GUARDED_BY(mu2);
danilchap5301e3c2017-09-06 11:10:2139#define RTC_PT_GUARDED_BY(x) RTC_THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x))
Henrik Kjellanderec78f1c2017-06-29 05:52:5040
41// Document the acquisition order between locks that can be held
42// simultaneously by a thread. For any two locks that need to be annotated
43// to establish an acquisition order, only one of them needs the annotation.
44// (i.e. You don't have to annotate both locks with both ACQUIRED_AFTER
45// and ACQUIRED_BEFORE.)
danilchap5301e3c2017-09-06 11:10:2146#define RTC_ACQUIRED_AFTER(x) \
47 RTC_THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(x))
danilchap5301e3c2017-09-06 11:10:2148#define RTC_ACQUIRED_BEFORE(x) \
49 RTC_THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(x))
Henrik Kjellanderec78f1c2017-06-29 05:52:5050
51// The following three annotations document the lock requirements for
52// functions/methods.
53
54// Document if a function expects certain locks to be held before it is called
danilchap5301e3c2017-09-06 11:10:2155#define RTC_EXCLUSIVE_LOCKS_REQUIRED(...) \
56 RTC_THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(__VA_ARGS__))
danilchap5301e3c2017-09-06 11:10:2157#define RTC_SHARED_LOCKS_REQUIRED(...) \
58 RTC_THREAD_ANNOTATION_ATTRIBUTE__(shared_locks_required(__VA_ARGS__))
Henrik Kjellanderec78f1c2017-06-29 05:52:5059
60// Document the locks acquired in the body of the function. These locks
61// cannot be held when calling this function (as google3's Mutex locks are
62// non-reentrant).
danilchap5301e3c2017-09-06 11:10:2163#define RTC_LOCKS_EXCLUDED(...) \
64 RTC_THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(__VA_ARGS__))
Henrik Kjellanderec78f1c2017-06-29 05:52:5065
66// Document the lock the annotated function returns without acquiring it.
danilchap5301e3c2017-09-06 11:10:2167#define RTC_LOCK_RETURNED(x) RTC_THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
Henrik Kjellanderec78f1c2017-06-29 05:52:5068
69// Document if a class/type is a lockable type (such as the Mutex class).
danilchap5301e3c2017-09-06 11:10:2170#define RTC_LOCKABLE RTC_THREAD_ANNOTATION_ATTRIBUTE__(lockable)
Henrik Kjellanderec78f1c2017-06-29 05:52:5071
72// Document if a class is a scoped lockable type (such as the MutexLock class).
danilchap5301e3c2017-09-06 11:10:2173#define RTC_SCOPED_LOCKABLE RTC_THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
Henrik Kjellanderec78f1c2017-06-29 05:52:5074
75// The following annotations specify lock and unlock primitives.
danilchap5301e3c2017-09-06 11:10:2176#define RTC_EXCLUSIVE_LOCK_FUNCTION(...) \
77 RTC_THREAD_ANNOTATION_ATTRIBUTE__(exclusive_lock_function(__VA_ARGS__))
Henrik Kjellanderec78f1c2017-06-29 05:52:5078
danilchap5301e3c2017-09-06 11:10:2179#define RTC_SHARED_LOCK_FUNCTION(...) \
80 RTC_THREAD_ANNOTATION_ATTRIBUTE__(shared_lock_function(__VA_ARGS__))
Henrik Kjellanderec78f1c2017-06-29 05:52:5081
danilchap5301e3c2017-09-06 11:10:2182#define RTC_EXCLUSIVE_TRYLOCK_FUNCTION(...) \
83 RTC_THREAD_ANNOTATION_ATTRIBUTE__(exclusive_trylock_function(__VA_ARGS__))
Henrik Kjellanderec78f1c2017-06-29 05:52:5084
danilchap5301e3c2017-09-06 11:10:2185#define RTC_SHARED_TRYLOCK_FUNCTION(...) \
86 RTC_THREAD_ANNOTATION_ATTRIBUTE__(shared_trylock_function(__VA_ARGS__))
Henrik Kjellanderec78f1c2017-06-29 05:52:5087
danilchap5301e3c2017-09-06 11:10:2188#define RTC_UNLOCK_FUNCTION(...) \
89 RTC_THREAD_ANNOTATION_ATTRIBUTE__(unlock_function(__VA_ARGS__))
Henrik Kjellanderec78f1c2017-06-29 05:52:5090
91// An escape hatch for thread safety analysis to ignore the annotated function.
danilchap5301e3c2017-09-06 11:10:2192#define RTC_NO_THREAD_SAFETY_ANALYSIS \
93 RTC_THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
andresp@webrtc.org7fb75ec2013-12-20 20:20:5094
Mirko Bonadei92ea95e2017-09-15 04:47:3195#endif // RTC_BASE_THREAD_ANNOTATIONS_H_