1/* Copyright (c) 2008-2009, Google Inc.
2 * All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Neither the name of Google Inc. nor the names of its
11 * contributors may be used to endorse or promote products derived from
12 * this software without specific prior written permission.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
15 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
18 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * ---
27 * Author: Kostya Serebryany
28 * Copied to CPython by Jeffrey Yasskin, with all macros renamed to
29 * start with _Py_ to avoid colliding with users embedding Python, and
30 * with deprecated macros removed.
31 */
32
33/* This file defines dynamic annotations for use with dynamic analysis
34   tool such as valgrind, PIN, etc.
35
36   Dynamic annotation is a source code annotation that affects
37   the generated code (that is, the annotation is not a comment).
38   Each such annotation is attached to a particular
39   instruction and/or to a particular object (address) in the program.
40
41   The annotations that should be used by users are macros in all upper-case
42   (e.g., _Py_ANNOTATE_NEW_MEMORY).
43
44   Actual implementation of these macros may differ depending on the
45   dynamic analysis tool being used.
46
47   See https://code.google.com/p/data-race-test/  for more information.
48
49   This file supports the following dynamic analysis tools:
50   - None (DYNAMIC_ANNOTATIONS_ENABLED is not defined or zero).
51      Macros are defined empty.
52   - ThreadSanitizer, Helgrind, DRD (DYNAMIC_ANNOTATIONS_ENABLED is 1).
53      Macros are defined as calls to non-inlinable empty functions
54      that are intercepted by Valgrind. */
55
56#ifndef __DYNAMIC_ANNOTATIONS_H__
57#define __DYNAMIC_ANNOTATIONS_H__
58
59#ifndef DYNAMIC_ANNOTATIONS_ENABLED
60# define DYNAMIC_ANNOTATIONS_ENABLED 0
61#endif
62
63#if DYNAMIC_ANNOTATIONS_ENABLED != 0
64
65  /* -------------------------------------------------------------
66     Annotations useful when implementing condition variables such as CondVar,
67     using conditional critical sections (Await/LockWhen) and when constructing
68     user-defined synchronization mechanisms.
69
70     The annotations _Py_ANNOTATE_HAPPENS_BEFORE() and
71     _Py_ANNOTATE_HAPPENS_AFTER() can be used to define happens-before arcs in
72     user-defined synchronization mechanisms: the race detector will infer an
73     arc from the former to the latter when they share the same argument
74     pointer.
75
76     Example 1 (reference counting):
77
78     void Unref() {
79       _Py_ANNOTATE_HAPPENS_BEFORE(&refcount_);
80       if (AtomicDecrementByOne(&refcount_) == 0) {
81         _Py_ANNOTATE_HAPPENS_AFTER(&refcount_);
82         delete this;
83       }
84     }
85
86     Example 2 (message queue):
87
88     void MyQueue::Put(Type *e) {
89       MutexLock lock(&mu_);
90       _Py_ANNOTATE_HAPPENS_BEFORE(e);
91       PutElementIntoMyQueue(e);
92     }
93
94     Type *MyQueue::Get() {
95       MutexLock lock(&mu_);
96       Type *e = GetElementFromMyQueue();
97       _Py_ANNOTATE_HAPPENS_AFTER(e);
98       return e;
99     }
100
101     Note: when possible, please use the existing reference counting and message
102     queue implementations instead of inventing new ones. */
103
104  /* Report that wait on the condition variable at address "cv" has succeeded
105     and the lock at address "lock" is held. */
106#define _Py_ANNOTATE_CONDVAR_LOCK_WAIT(cv, lock) \
107    AnnotateCondVarWait(__FILE__, __LINE__, cv, lock)
108
109  /* Report that wait on the condition variable at "cv" has succeeded.  Variant
110     w/o lock. */
111#define _Py_ANNOTATE_CONDVAR_WAIT(cv) \
112    AnnotateCondVarWait(__FILE__, __LINE__, cv, NULL)
113
114  /* Report that we are about to signal on the condition variable at address
115     "cv". */
116#define _Py_ANNOTATE_CONDVAR_SIGNAL(cv) \
117    AnnotateCondVarSignal(__FILE__, __LINE__, cv)
118
119  /* Report that we are about to signal_all on the condition variable at "cv". */
120#define _Py_ANNOTATE_CONDVAR_SIGNAL_ALL(cv) \
121    AnnotateCondVarSignalAll(__FILE__, __LINE__, cv)
122
123  /* Annotations for user-defined synchronization mechanisms. */
124#define _Py_ANNOTATE_HAPPENS_BEFORE(obj) _Py_ANNOTATE_CONDVAR_SIGNAL(obj)
125#define _Py_ANNOTATE_HAPPENS_AFTER(obj)  _Py_ANNOTATE_CONDVAR_WAIT(obj)
126
127  /* Report that the bytes in the range [pointer, pointer+size) are about
128     to be published safely. The race checker will create a happens-before
129     arc from the call _Py_ANNOTATE_PUBLISH_MEMORY_RANGE(pointer, size) to
130     subsequent accesses to this memory.
131     Note: this annotation may not work properly if the race detector uses
132     sampling, i.e. does not observe all memory accesses.
133     */
134#define _Py_ANNOTATE_PUBLISH_MEMORY_RANGE(pointer, size) \
135    AnnotatePublishMemoryRange(__FILE__, __LINE__, pointer, size)
136
137  /* Instruct the tool to create a happens-before arc between mu->Unlock() and
138     mu->Lock(). This annotation may slow down the race detector and hide real
139     races. Normally it is used only when it would be difficult to annotate each
140     of the mutex's critical sections individually using the annotations above.
141     This annotation makes sense only for hybrid race detectors. For pure
142     happens-before detectors this is a no-op. For more details see
143     https://code.google.com/p/data-race-test/wiki/PureHappensBeforeVsHybrid . */
144#define _Py_ANNOTATE_PURE_HAPPENS_BEFORE_MUTEX(mu) \
145    AnnotateMutexIsUsedAsCondVar(__FILE__, __LINE__, mu)
146
147  /* -------------------------------------------------------------
148     Annotations useful when defining memory allocators, or when memory that
149     was protected in one way starts to be protected in another. */
150
151  /* Report that a new memory at "address" of size "size" has been allocated.
152     This might be used when the memory has been retrieved from a free list and
153     is about to be reused, or when the locking discipline for a variable
154     changes. */
155#define _Py_ANNOTATE_NEW_MEMORY(address, size) \
156    AnnotateNewMemory(__FILE__, __LINE__, address, size)
157
158  /* -------------------------------------------------------------
159     Annotations useful when defining FIFO queues that transfer data between
160     threads. */
161
162  /* Report that the producer-consumer queue (such as ProducerConsumerQueue) at
163     address "pcq" has been created.  The _Py_ANNOTATE_PCQ_* annotations should
164     be used only for FIFO queues.  For non-FIFO queues use
165     _Py_ANNOTATE_HAPPENS_BEFORE (for put) and _Py_ANNOTATE_HAPPENS_AFTER (for
166     get). */
167#define _Py_ANNOTATE_PCQ_CREATE(pcq) \
168    AnnotatePCQCreate(__FILE__, __LINE__, pcq)
169
170  /* Report that the queue at address "pcq" is about to be destroyed. */
171#define _Py_ANNOTATE_PCQ_DESTROY(pcq) \
172    AnnotatePCQDestroy(__FILE__, __LINE__, pcq)
173
174  /* Report that we are about to put an element into a FIFO queue at address
175     "pcq". */
176#define _Py_ANNOTATE_PCQ_PUT(pcq) \
177    AnnotatePCQPut(__FILE__, __LINE__, pcq)
178
179  /* Report that we've just got an element from a FIFO queue at address "pcq". */
180#define _Py_ANNOTATE_PCQ_GET(pcq) \
181    AnnotatePCQGet(__FILE__, __LINE__, pcq)
182
183  /* -------------------------------------------------------------
184     Annotations that suppress errors.  It is usually better to express the
185     program's synchronization using the other annotations, but these can
186     be used when all else fails. */
187
188  /* Report that we may have a benign race at "pointer", with size
189     "sizeof(*(pointer))". "pointer" must be a non-void* pointer.  Insert at the
190     point where "pointer" has been allocated, preferably close to the point
191     where the race happens.  See also _Py_ANNOTATE_BENIGN_RACE_STATIC. */
192#define _Py_ANNOTATE_BENIGN_RACE(pointer, description) \
193    AnnotateBenignRaceSized(__FILE__, __LINE__, pointer, \
194                            sizeof(*(pointer)), description)
195
196  /* Same as _Py_ANNOTATE_BENIGN_RACE(address, description), but applies to
197     the memory range [address, address+size). */
198#define _Py_ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
199    AnnotateBenignRaceSized(__FILE__, __LINE__, address, size, description)
200
201  /* Request the analysis tool to ignore all reads in the current thread
202     until _Py_ANNOTATE_IGNORE_READS_END is called.
203     Useful to ignore intentional racey reads, while still checking
204     other reads and all writes.
205     See also _Py_ANNOTATE_UNPROTECTED_READ. */
206#define _Py_ANNOTATE_IGNORE_READS_BEGIN() \
207    AnnotateIgnoreReadsBegin(__FILE__, __LINE__)
208
209  /* Stop ignoring reads. */
210#define _Py_ANNOTATE_IGNORE_READS_END() \
211    AnnotateIgnoreReadsEnd(__FILE__, __LINE__)
212
213  /* Similar to _Py_ANNOTATE_IGNORE_READS_BEGIN, but ignore writes. */
214#define _Py_ANNOTATE_IGNORE_WRITES_BEGIN() \
215    AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
216
217  /* Stop ignoring writes. */
218#define _Py_ANNOTATE_IGNORE_WRITES_END() \
219    AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
220
221  /* Start ignoring all memory accesses (reads and writes). */
222#define _Py_ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
223    do {\
224      _Py_ANNOTATE_IGNORE_READS_BEGIN();\
225      _Py_ANNOTATE_IGNORE_WRITES_BEGIN();\
226    }while(0)\
227
228  /* Stop ignoring all memory accesses. */
229#define _Py_ANNOTATE_IGNORE_READS_AND_WRITES_END() \
230    do {\
231      _Py_ANNOTATE_IGNORE_WRITES_END();\
232      _Py_ANNOTATE_IGNORE_READS_END();\
233    }while(0)\
234
235  /* Similar to _Py_ANNOTATE_IGNORE_READS_BEGIN, but ignore synchronization events:
236     RWLOCK* and CONDVAR*. */
237#define _Py_ANNOTATE_IGNORE_SYNC_BEGIN() \
238    AnnotateIgnoreSyncBegin(__FILE__, __LINE__)
239
240  /* Stop ignoring sync events. */
241#define _Py_ANNOTATE_IGNORE_SYNC_END() \
242    AnnotateIgnoreSyncEnd(__FILE__, __LINE__)
243
244
245  /* Enable (enable!=0) or disable (enable==0) race detection for all threads.
246     This annotation could be useful if you want to skip expensive race analysis
247     during some period of program execution, e.g. during initialization. */
248#define _Py_ANNOTATE_ENABLE_RACE_DETECTION(enable) \
249    AnnotateEnableRaceDetection(__FILE__, __LINE__, enable)
250
251  /* -------------------------------------------------------------
252     Annotations useful for debugging. */
253
254  /* Request to trace every access to "address". */
255#define _Py_ANNOTATE_TRACE_MEMORY(address) \
256    AnnotateTraceMemory(__FILE__, __LINE__, address)
257
258  /* Report the current thread name to a race detector. */
259#define _Py_ANNOTATE_THREAD_NAME(name) \
260    AnnotateThreadName(__FILE__, __LINE__, name)
261
262  /* -------------------------------------------------------------
263     Annotations useful when implementing locks.  They are not
264     normally needed by modules that merely use locks.
265     The "lock" argument is a pointer to the lock object. */
266
267  /* Report that a lock has been created at address "lock". */
268#define _Py_ANNOTATE_RWLOCK_CREATE(lock) \
269    AnnotateRWLockCreate(__FILE__, __LINE__, lock)
270
271  /* Report that the lock at address "lock" is about to be destroyed. */
272#define _Py_ANNOTATE_RWLOCK_DESTROY(lock) \
273    AnnotateRWLockDestroy(__FILE__, __LINE__, lock)
274
275  /* Report that the lock at address "lock" has been acquired.
276     is_w=1 for writer lock, is_w=0 for reader lock. */
277#define _Py_ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) \
278    AnnotateRWLockAcquired(__FILE__, __LINE__, lock, is_w)
279
280  /* Report that the lock at address "lock" is about to be released. */
281#define _Py_ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
282    AnnotateRWLockReleased(__FILE__, __LINE__, lock, is_w)
283
284  /* -------------------------------------------------------------
285     Annotations useful when implementing barriers.  They are not
286     normally needed by modules that merely use barriers.
287     The "barrier" argument is a pointer to the barrier object. */
288
289  /* Report that the "barrier" has been initialized with initial "count".
290   If 'reinitialization_allowed' is true, initialization is allowed to happen
291   multiple times w/o calling barrier_destroy() */
292#define _Py_ANNOTATE_BARRIER_INIT(barrier, count, reinitialization_allowed) \
293    AnnotateBarrierInit(__FILE__, __LINE__, barrier, count, \
294                        reinitialization_allowed)
295
296  /* Report that we are about to enter barrier_wait("barrier"). */
297#define _Py_ANNOTATE_BARRIER_WAIT_BEFORE(barrier) \
298    AnnotateBarrierWaitBefore(__FILE__, __LINE__, barrier)
299
300  /* Report that we just exited barrier_wait("barrier"). */
301#define _Py_ANNOTATE_BARRIER_WAIT_AFTER(barrier) \
302    AnnotateBarrierWaitAfter(__FILE__, __LINE__, barrier)
303
304  /* Report that the "barrier" has been destroyed. */
305#define _Py_ANNOTATE_BARRIER_DESTROY(barrier) \
306    AnnotateBarrierDestroy(__FILE__, __LINE__, barrier)
307
308  /* -------------------------------------------------------------
309     Annotations useful for testing race detectors. */
310
311  /* Report that we expect a race on the variable at "address".
312     Use only in unit tests for a race detector. */
313#define _Py_ANNOTATE_EXPECT_RACE(address, description) \
314    AnnotateExpectRace(__FILE__, __LINE__, address, description)
315
316  /* A no-op. Insert where you like to test the interceptors. */
317#define _Py_ANNOTATE_NO_OP(arg) \
318    AnnotateNoOp(__FILE__, __LINE__, arg)
319
320  /* Force the race detector to flush its state. The actual effect depends on
321   * the implementation of the detector. */
322#define _Py_ANNOTATE_FLUSH_STATE() \
323    AnnotateFlushState(__FILE__, __LINE__)
324
325
326#else  /* DYNAMIC_ANNOTATIONS_ENABLED == 0 */
327
328#define _Py_ANNOTATE_RWLOCK_CREATE(lock) /* empty */
329#define _Py_ANNOTATE_RWLOCK_DESTROY(lock) /* empty */
330#define _Py_ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) /* empty */
331#define _Py_ANNOTATE_RWLOCK_RELEASED(lock, is_w) /* empty */
332#define _Py_ANNOTATE_BARRIER_INIT(barrier, count, reinitialization_allowed) /* */
333#define _Py_ANNOTATE_BARRIER_WAIT_BEFORE(barrier) /* empty */
334#define _Py_ANNOTATE_BARRIER_WAIT_AFTER(barrier) /* empty */
335#define _Py_ANNOTATE_BARRIER_DESTROY(barrier) /* empty */
336#define _Py_ANNOTATE_CONDVAR_LOCK_WAIT(cv, lock) /* empty */
337#define _Py_ANNOTATE_CONDVAR_WAIT(cv) /* empty */
338#define _Py_ANNOTATE_CONDVAR_SIGNAL(cv) /* empty */
339#define _Py_ANNOTATE_CONDVAR_SIGNAL_ALL(cv) /* empty */
340#define _Py_ANNOTATE_HAPPENS_BEFORE(obj) /* empty */
341#define _Py_ANNOTATE_HAPPENS_AFTER(obj) /* empty */
342#define _Py_ANNOTATE_PUBLISH_MEMORY_RANGE(address, size) /* empty */
343#define _Py_ANNOTATE_UNPUBLISH_MEMORY_RANGE(address, size)  /* empty */
344#define _Py_ANNOTATE_SWAP_MEMORY_RANGE(address, size)  /* empty */
345#define _Py_ANNOTATE_PCQ_CREATE(pcq) /* empty */
346#define _Py_ANNOTATE_PCQ_DESTROY(pcq) /* empty */
347#define _Py_ANNOTATE_PCQ_PUT(pcq) /* empty */
348#define _Py_ANNOTATE_PCQ_GET(pcq) /* empty */
349#define _Py_ANNOTATE_NEW_MEMORY(address, size) /* empty */
350#define _Py_ANNOTATE_EXPECT_RACE(address, description) /* empty */
351#define _Py_ANNOTATE_BENIGN_RACE(address, description) /* empty */
352#define _Py_ANNOTATE_BENIGN_RACE_SIZED(address, size, description) /* empty */
353#define _Py_ANNOTATE_PURE_HAPPENS_BEFORE_MUTEX(mu) /* empty */
354#define _Py_ANNOTATE_MUTEX_IS_USED_AS_CONDVAR(mu) /* empty */
355#define _Py_ANNOTATE_TRACE_MEMORY(arg) /* empty */
356#define _Py_ANNOTATE_THREAD_NAME(name) /* empty */
357#define _Py_ANNOTATE_IGNORE_READS_BEGIN() /* empty */
358#define _Py_ANNOTATE_IGNORE_READS_END() /* empty */
359#define _Py_ANNOTATE_IGNORE_WRITES_BEGIN() /* empty */
360#define _Py_ANNOTATE_IGNORE_WRITES_END() /* empty */
361#define _Py_ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() /* empty */
362#define _Py_ANNOTATE_IGNORE_READS_AND_WRITES_END() /* empty */
363#define _Py_ANNOTATE_IGNORE_SYNC_BEGIN() /* empty */
364#define _Py_ANNOTATE_IGNORE_SYNC_END() /* empty */
365#define _Py_ANNOTATE_ENABLE_RACE_DETECTION(enable) /* empty */
366#define _Py_ANNOTATE_NO_OP(arg) /* empty */
367#define _Py_ANNOTATE_FLUSH_STATE() /* empty */
368
369#endif  /* DYNAMIC_ANNOTATIONS_ENABLED */
370
371/* Use the macros above rather than using these functions directly. */
372#ifdef __cplusplus
373extern "C" {
374#endif
375void AnnotateRWLockCreate(const char *file, int line,
376                          const volatile void *lock);
377void AnnotateRWLockDestroy(const char *file, int line,
378                           const volatile void *lock);
379void AnnotateRWLockAcquired(const char *file, int line,
380                            const volatile void *lock, long is_w);
381void AnnotateRWLockReleased(const char *file, int line,
382                            const volatile void *lock, long is_w);
383void AnnotateBarrierInit(const char *file, int line,
384                         const volatile void *barrier, long count,
385                         long reinitialization_allowed);
386void AnnotateBarrierWaitBefore(const char *file, int line,
387                               const volatile void *barrier);
388void AnnotateBarrierWaitAfter(const char *file, int line,
389                              const volatile void *barrier);
390void AnnotateBarrierDestroy(const char *file, int line,
391                            const volatile void *barrier);
392void AnnotateCondVarWait(const char *file, int line,
393                         const volatile void *cv,
394                         const volatile void *lock);
395void AnnotateCondVarSignal(const char *file, int line,
396                           const volatile void *cv);
397void AnnotateCondVarSignalAll(const char *file, int line,
398                              const volatile void *cv);
399void AnnotatePublishMemoryRange(const char *file, int line,
400                                const volatile void *address,
401                                long size);
402void AnnotateUnpublishMemoryRange(const char *file, int line,
403                                  const volatile void *address,
404                                  long size);
405void AnnotatePCQCreate(const char *file, int line,
406                       const volatile void *pcq);
407void AnnotatePCQDestroy(const char *file, int line,
408                        const volatile void *pcq);
409void AnnotatePCQPut(const char *file, int line,
410                    const volatile void *pcq);
411void AnnotatePCQGet(const char *file, int line,
412                    const volatile void *pcq);
413void AnnotateNewMemory(const char *file, int line,
414                       const volatile void *address,
415                       long size);
416void AnnotateExpectRace(const char *file, int line,
417                        const volatile void *address,
418                        const char *description);
419void AnnotateBenignRace(const char *file, int line,
420                        const volatile void *address,
421                        const char *description);
422void AnnotateBenignRaceSized(const char *file, int line,
423                        const volatile void *address,
424                        long size,
425                        const char *description);
426void AnnotateMutexIsUsedAsCondVar(const char *file, int line,
427                                  const volatile void *mu);
428void AnnotateTraceMemory(const char *file, int line,
429                         const volatile void *arg);
430void AnnotateThreadName(const char *file, int line,
431                        const char *name);
432void AnnotateIgnoreReadsBegin(const char *file, int line);
433void AnnotateIgnoreReadsEnd(const char *file, int line);
434void AnnotateIgnoreWritesBegin(const char *file, int line);
435void AnnotateIgnoreWritesEnd(const char *file, int line);
436void AnnotateEnableRaceDetection(const char *file, int line, int enable);
437void AnnotateNoOp(const char *file, int line,
438                  const volatile void *arg);
439void AnnotateFlushState(const char *file, int line);
440
441/* Return non-zero value if running under valgrind.
442
443  If "valgrind.h" is included into dynamic_annotations.c,
444  the regular valgrind mechanism will be used.
445  See http://valgrind.org/docs/manual/manual-core-adv.html about
446  RUNNING_ON_VALGRIND and other valgrind "client requests".
447  The file "valgrind.h" may be obtained by doing
448     svn co svn://svn.valgrind.org/valgrind/trunk/include
449
450  If for some reason you can't use "valgrind.h" or want to fake valgrind,
451  there are two ways to make this function return non-zero:
452    - Use environment variable: export RUNNING_ON_VALGRIND=1
453    - Make your tool intercept the function RunningOnValgrind() and
454      change its return value.
455 */
456int RunningOnValgrind(void);
457
458#ifdef __cplusplus
459}
460#endif
461
462#if DYNAMIC_ANNOTATIONS_ENABLED != 0 && defined(__cplusplus)
463
464  /* _Py_ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
465
466     Instead of doing
467        _Py_ANNOTATE_IGNORE_READS_BEGIN();
468        ... = x;
469        _Py_ANNOTATE_IGNORE_READS_END();
470     one can use
471        ... = _Py_ANNOTATE_UNPROTECTED_READ(x); */
472  template <class T>
473  inline T _Py_ANNOTATE_UNPROTECTED_READ(const volatile T &x) {
474    _Py_ANNOTATE_IGNORE_READS_BEGIN();
475    T res = x;
476    _Py_ANNOTATE_IGNORE_READS_END();
477    return res;
478  }
479  /* Apply _Py_ANNOTATE_BENIGN_RACE_SIZED to a static variable. */
480#define _Py_ANNOTATE_BENIGN_RACE_STATIC(static_var, description)        \
481    namespace {                                                       \
482      class static_var ## _annotator {                                \
483       public:                                                        \
484        static_var ## _annotator() {                                  \
485          _Py_ANNOTATE_BENIGN_RACE_SIZED(&static_var,                     \
486                                      sizeof(static_var),             \
487            # static_var ": " description);                           \
488        }                                                             \
489      };                                                              \
490      static static_var ## _annotator the ## static_var ## _annotator;\
491    }
492#else /* DYNAMIC_ANNOTATIONS_ENABLED == 0 */
493
494#define _Py_ANNOTATE_UNPROTECTED_READ(x) (x)
495#define _Py_ANNOTATE_BENIGN_RACE_STATIC(static_var, description)  /* empty */
496
497#endif /* DYNAMIC_ANNOTATIONS_ENABLED */
498
499#endif  /* __DYNAMIC_ANNOTATIONS_H__ */
500