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1 // | 1 // |
2 // Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. | 2 // Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. |
3 // | 3 // |
4 // Use of this source code is governed by a BSD-style license | 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 | 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 | 6 // tree. An additional intellectual property rights grant can be found |
7 // in the file PATENTS. All contributing project authors may | 7 // in the file PATENTS. All contributing project authors may |
8 // be found in the AUTHORS file in the root of the source tree. | 8 // be found in the AUTHORS file in the root of the source tree. |
9 // | 9 // |
10 // Borrowed from | 10 // Borrowed from |
11 // https://code.google.com/p/gperftools/source/browse/src/base/thread_annotation
s.h | 11 // https://code.google.com/p/gperftools/source/browse/src/base/thread_annotation
s.h |
12 // but adapted for clang attributes instead of the gcc. | 12 // but adapted for clang attributes instead of the gcc. |
13 // | 13 // |
14 // This header file contains the macro definitions for thread safety | 14 // This header file contains the macro definitions for thread safety |
15 // annotations that allow the developers to document the locking policies | 15 // annotations that allow the developers to document the locking policies |
16 // of their multi-threaded code. The annotations can also help program | 16 // of their multi-threaded code. The annotations can also help program |
17 // analysis tools to identify potential thread safety issues. | 17 // analysis tools to identify potential thread safety issues. |
18 | 18 |
19 #ifndef WEBRTC_BASE_THREAD_ANNOTATIONS_H_ | 19 #ifndef WEBRTC_BASE_THREAD_ANNOTATIONS_H_ |
20 #define WEBRTC_BASE_THREAD_ANNOTATIONS_H_ | 20 #define WEBRTC_BASE_THREAD_ANNOTATIONS_H_ |
21 | 21 |
22 #if defined(__clang__) && (!defined(SWIG)) | |
23 #define THREAD_ANNOTATION_ATTRIBUTE__(x) __attribute__((x)) | |
24 #else | |
25 #define THREAD_ANNOTATION_ATTRIBUTE__(x) // no-op | |
26 #endif | |
27 | 22 |
28 // Document if a shared variable/field needs to be protected by a lock. | 23 // This header is deprecated and is just left here temporarily during |
29 // GUARDED_BY allows the user to specify a particular lock that should be | 24 // refactoring. See https://bugs.webrtc.org/7634 for more details. |
30 // held when accessing the annotated variable, while GUARDED_VAR only | 25 #include "webrtc/rtc_base/thread_annotations.h" |
31 // indicates a shared variable should be guarded (by any lock). GUARDED_VAR | |
32 // is primarily used when the client cannot express the name of the lock. | |
33 #define GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x)) | |
34 #define GUARDED_VAR THREAD_ANNOTATION_ATTRIBUTE__(guarded_var) | |
35 | |
36 // Document if the memory location pointed to by a pointer should be guarded | |
37 // by a lock when dereferencing the pointer. Similar to GUARDED_VAR, | |
38 // PT_GUARDED_VAR is primarily used when the client cannot express the name | |
39 // of the lock. Note that a pointer variable to a shared memory location | |
40 // could itself be a shared variable. For example, if a shared global pointer | |
41 // q, which is guarded by mu1, points to a shared memory location that is | |
42 // guarded by mu2, q should be annotated as follows: | |
43 // int *q GUARDED_BY(mu1) PT_GUARDED_BY(mu2); | |
44 #define PT_GUARDED_BY(x) THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x)) | |
45 #define PT_GUARDED_VAR THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_var) | |
46 | |
47 // Document the acquisition order between locks that can be held | |
48 // simultaneously by a thread. For any two locks that need to be annotated | |
49 // to establish an acquisition order, only one of them needs the annotation. | |
50 // (i.e. You don't have to annotate both locks with both ACQUIRED_AFTER | |
51 // and ACQUIRED_BEFORE.) | |
52 #define ACQUIRED_AFTER(x) THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(x)) | |
53 #define ACQUIRED_BEFORE(x) THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(x)) | |
54 | |
55 // The following three annotations document the lock requirements for | |
56 // functions/methods. | |
57 | |
58 // Document if a function expects certain locks to be held before it is called | |
59 #define EXCLUSIVE_LOCKS_REQUIRED(...) \ | |
60 THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(__VA_ARGS__)) | |
61 | |
62 #define SHARED_LOCKS_REQUIRED(...) \ | |
63 THREAD_ANNOTATION_ATTRIBUTE__(shared_locks_required(__VA_ARGS__)) | |
64 | |
65 // Document the locks acquired in the body of the function. These locks | |
66 // cannot be held when calling this function (as google3's Mutex locks are | |
67 // non-reentrant). | |
68 #define LOCKS_EXCLUDED(...) \ | |
69 THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(__VA_ARGS__)) | |
70 | |
71 // Document the lock the annotated function returns without acquiring it. | |
72 #define LOCK_RETURNED(x) THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x)) | |
73 | |
74 // Document if a class/type is a lockable type (such as the Mutex class). | |
75 #define LOCKABLE THREAD_ANNOTATION_ATTRIBUTE__(lockable) | |
76 | |
77 // Document if a class is a scoped lockable type (such as the MutexLock class). | |
78 #define SCOPED_LOCKABLE THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable) | |
79 | |
80 // The following annotations specify lock and unlock primitives. | |
81 #define EXCLUSIVE_LOCK_FUNCTION(...) \ | |
82 THREAD_ANNOTATION_ATTRIBUTE__(exclusive_lock_function(__VA_ARGS__)) | |
83 | |
84 #define SHARED_LOCK_FUNCTION(...) \ | |
85 THREAD_ANNOTATION_ATTRIBUTE__(shared_lock_function(__VA_ARGS__)) | |
86 | |
87 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) \ | |
88 THREAD_ANNOTATION_ATTRIBUTE__(exclusive_trylock_function(__VA_ARGS__)) | |
89 | |
90 #define SHARED_TRYLOCK_FUNCTION(...) \ | |
91 THREAD_ANNOTATION_ATTRIBUTE__(shared_trylock_function(__VA_ARGS__)) | |
92 | |
93 #define UNLOCK_FUNCTION(...) \ | |
94 THREAD_ANNOTATION_ATTRIBUTE__(unlock_function(__VA_ARGS__)) | |
95 | |
96 // An escape hatch for thread safety analysis to ignore the annotated function. | |
97 #define NO_THREAD_SAFETY_ANALYSIS \ | |
98 THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis) | |
99 | 26 |
100 #endif // WEBRTC_BASE_THREAD_ANNOTATIONS_H_ | 27 #endif // WEBRTC_BASE_THREAD_ANNOTATIONS_H_ |
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