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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 http://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      http://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
373 extern "C" {
374 #endif
375 void AnnotateRWLockCreate(const char *file, int line,
376                           const volatile void *lock);
377 void AnnotateRWLockDestroy(const char *file, int line,
378                            const volatile void *lock);
379 void AnnotateRWLockAcquired(const char *file, int line,
380                             const volatile void *lock, long is_w);
381 void AnnotateRWLockReleased(const char *file, int line,
382                             const volatile void *lock, long is_w);
383 void AnnotateBarrierInit(const char *file, int line,
384                          const volatile void *barrier, long count,
385                          long reinitialization_allowed);
386 void AnnotateBarrierWaitBefore(const char *file, int line,
387                                const volatile void *barrier);
388 void AnnotateBarrierWaitAfter(const char *file, int line,
389                               const volatile void *barrier);
390 void AnnotateBarrierDestroy(const char *file, int line,
391                             const volatile void *barrier);
392 void AnnotateCondVarWait(const char *file, int line,
393                          const volatile void *cv,
394                          const volatile void *lock);
395 void AnnotateCondVarSignal(const char *file, int line,
396                            const volatile void *cv);
397 void AnnotateCondVarSignalAll(const char *file, int line,
398                               const volatile void *cv);
399 void AnnotatePublishMemoryRange(const char *file, int line,
400                                 const volatile void *address,
401                                 long size);
402 void AnnotateUnpublishMemoryRange(const char *file, int line,
403                                   const volatile void *address,
404                                   long size);
405 void AnnotatePCQCreate(const char *file, int line,
406                        const volatile void *pcq);
407 void AnnotatePCQDestroy(const char *file, int line,
408                         const volatile void *pcq);
409 void AnnotatePCQPut(const char *file, int line,
410                     const volatile void *pcq);
411 void AnnotatePCQGet(const char *file, int line,
412                     const volatile void *pcq);
413 void AnnotateNewMemory(const char *file, int line,
414                        const volatile void *address,
415                        long size);
416 void AnnotateExpectRace(const char *file, int line,
417                         const volatile void *address,
418                         const char *description);
419 void AnnotateBenignRace(const char *file, int line,
420                         const volatile void *address,
421                         const char *description);
422 void AnnotateBenignRaceSized(const char *file, int line,
423                         const volatile void *address,
424                         long size,
425                         const char *description);
426 void AnnotateMutexIsUsedAsCondVar(const char *file, int line,
427                                   const volatile void *mu);
428 void AnnotateTraceMemory(const char *file, int line,
429                          const volatile void *arg);
430 void AnnotateThreadName(const char *file, int line,
431                         const char *name);
432 void AnnotateIgnoreReadsBegin(const char *file, int line);
433 void AnnotateIgnoreReadsEnd(const char *file, int line);
434 void AnnotateIgnoreWritesBegin(const char *file, int line);
435 void AnnotateIgnoreWritesEnd(const char *file, int line);
436 void AnnotateEnableRaceDetection(const char *file, int line, int enable);
437 void AnnotateNoOp(const char *file, int line,
438                   const volatile void *arg);
439 void 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  */
456 int 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>
_Py_ANNOTATE_UNPROTECTED_READ(const volatile T & x)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