path: root/base/dynamic_annotations.h

// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This file defines dynamic annotations for use with dynamic analysis
// tool such as valgrind, PIN, etc.
//
// Dynamic annotation is a source code annotation that affects
// the generated code (that is, the annotation is not a comment).
// Each such annotation is attached to a particular
// instruction and/or to a particular object (address) in the program.
//
// The annotations that should be used by users are macros in all upper-case
// (e.g., ANNOTATE_NEW_MEMORY).
//
// Actual implementation of these macros may differ depending on the
// dynamic analysis tool being used.
//
// This file supports the following dynamic analysis tools:
// - None (NVALGRIND is defined).
//    Macros are defined empty.
// - ThreadSanitizer (NVALGRIND is not defined).
//    Macros are defined as calls to non-inlinable empty functions
//    that are intercepted by ThreadSanitizer.
//
#ifndef BASE_DYNAMIC_ANNOTATIONS_H_
#define BASE_DYNAMIC_ANNOTATIONS_H_

#ifdef __GNUC__
// valgrind.h uses gcc extensions so it may not build with other compilers.
// Also, it defines NVALGRIND on Windows, which disables dynamic annotations
// for ThreadSanitizer.
#include "base/third_party/valgrind/valgrind.h"
#endif

#ifndef NVALGRIND
// -------------------------------------------------------------
// Annotations useful when implementing condition variables such as CondVar,
// using conditional critical sections (Await/LockWhen) and when constructing
// user-defined synchronization mechanisms.
//
// The annotations ANNOTATE_HAPPENS_BEFORE() and ANNOTATE_HAPPENS_AFTER() can
// be used to define happens-before arcs in user-defined synchronization
// mechanisms:  the race detector will infer an arc from the former to the
// latter when they share the same argument pointer.
//
// Example 1 (reference counting):
//
// void Unref() {
//   ANNOTATE_HAPPENS_BEFORE(&refcount_);
//   if (AtomicDecrementByOne(&refcount_) == 0) {
//     ANNOTATE_HAPPENS_AFTER(&refcount_);
//     delete this;
//   }
// }
//
// Example 2 (message queue):
//
// void MyQueue::Put(Type *e) {
//   MutexLock lock(&mu_);
//   ANNOTATE_HAPPENS_BEFORE(e);
//   PutElementIntoMyQueue(e);
// }
//
// Type *MyQueue::Get() {
//   MutexLock lock(&mu_);
//   Type *e = GetElementFromMyQueue();
//   ANNOTATE_HAPPENS_AFTER(e);
//   return e;
// }
//
// Note: when possible, please use the existing reference counting and message
// queue implementations instead of inventing new ones.

// Report that wait on the condition variable at address "cv" has succeeded
// and the lock at address "lock" is held.
#define ANNOTATE_CONDVAR_LOCK_WAIT(cv, lock) \
  AnnotateCondVarWait(__FILE__, __LINE__, cv, lock)

// Report that wait on the condition variable at "cv" has succeeded.  Variant
// w/o lock.
#define ANNOTATE_CONDVAR_WAIT(cv) \
  AnnotateCondVarWait(__FILE__, __LINE__, cv, NULL)

// Report that we are about to signal on the condition variable at address
// "cv".
#define ANNOTATE_CONDVAR_SIGNAL(cv) \
  AnnotateCondVarSignal(__FILE__, __LINE__, cv)

// Report that we are about to signal_all on the condition variable at "cv".
#define ANNOTATE_CONDVAR_SIGNAL_ALL(cv) \
  AnnotateCondVarSignalAll(__FILE__, __LINE__, cv)

// Annotations for user-defined synchronization mechanisms.
#define ANNOTATE_HAPPENS_BEFORE(obj) ANNOTATE_CONDVAR_SIGNAL(obj)
#define ANNOTATE_HAPPENS_AFTER(obj)  ANNOTATE_CONDVAR_WAIT(obj)

// Report that the bytes in the range [pointer, pointer+size) are about
// to be published safely. The race checker will create a happens-before
// arc from the call ANNOTATE_PUBLISH_MEMORY_RANGE(pointer, size) to
// subsequent accesses to this memory.
#define ANNOTATE_PUBLISH_MEMORY_RANGE(pointer, size) \
  AnnotatePublishMemoryRange(__FILE__, __LINE__, pointer, size)

// Instruct the tool to create a happens-before arc between mu->Unlock() and
// mu->Lock().  This annotation may slow down the race detector; normally it
// is used only when it would be difficult to annotate each of the mutex's
// critical sections individually using the annotations above.
#define ANNOTATE_MUTEX_IS_USED_AS_CONDVAR(mu) \
  AnnotateMutexIsUsedAsCondVar(__FILE__, __LINE__, mu)

// -------------------------------------------------------------
// Annotations useful when defining memory allocators, or when memory that
// was protected in one way starts to be protected in another.

// Report that a new memory at "address" of size "size" has been allocated.
// This might be used when the memory has been retrieved from a free list and
// is about to be reused, or when a the locking discipline for a variable
// changes.
#define ANNOTATE_NEW_MEMORY(address, size) \
  AnnotateNewMemory(__FILE__, __LINE__, address, size)

// -------------------------------------------------------------
// Annotations useful when defining FIFO queues that transfer data between
// threads.

// Report that the producer-consumer queue (such as ProducerConsumerQueue) at
// address "pcq" has been created.  The ANNOTATE_PCQ_* annotations
// should be used only for FIFO queues.  For non-FIFO queues use
// ANNOTATE_HAPPENS_BEFORE (for put) and ANNOTATE_HAPPENS_AFTER (for get).
#define ANNOTATE_PCQ_CREATE(pcq) \
  AnnotatePCQCreate(__FILE__, __LINE__, pcq)

// Report that the queue at address "pcq" is about to be destroyed.
#define ANNOTATE_PCQ_DESTROY(pcq) \
  AnnotatePCQDestroy(__FILE__, __LINE__, pcq)

// Report that we are about to put an element into a FIFO queue at address
// "pcq".
#define ANNOTATE_PCQ_PUT(pcq) \
  AnnotatePCQPut(__FILE__, __LINE__, pcq)

// Report that we've just got an element from a FIFO queue at address "pcq".
#define ANNOTATE_PCQ_GET(pcq) \
  AnnotatePCQGet(__FILE__, __LINE__, pcq)

// -------------------------------------------------------------
// Annotations that suppress errors.  It is usually better to express the
// program's synchronization using the other annotations, but these can
// be used when all else fails.

// Report that we may have a benign race on at "address".
// Insert at the point where "address" has been allocated, preferably close
// to the point where the race happens.
// See also ANNOTATE_BENIGN_RACE_STATIC.
#define ANNOTATE_BENIGN_RACE(address, description) \
  AnnotateBenignRace(__FILE__, __LINE__, address, description)

// Request the analysis tool to ignore all reads in the current thread
// until ANNOTATE_IGNORE_READS_END is called.
// Useful to ignore intentional racey reads, while still checking
// other reads and all writes.
// See also ANNOTATE_UNPROTECTED_READ.
#define ANNOTATE_IGNORE_READS_BEGIN() \
  AnnotateIgnoreReadsBegin(__FILE__, __LINE__)

// Stop ignoring reads.
#define ANNOTATE_IGNORE_READS_END() \
  AnnotateIgnoreReadsEnd(__FILE__, __LINE__)

// Similar to ANNOTATE_IGNORE_READS_BEGIN, but ignore writes.
#define ANNOTATE_IGNORE_WRITES_BEGIN() \
  AnnotateIgnoreWritesBegin(__FILE__, __LINE__)

// Stop ignoring writes.
#define ANNOTATE_IGNORE_WRITES_END() \
  AnnotateIgnoreWritesEnd(__FILE__, __LINE__)

// Start ignoring all memory accesses (reads and writes).
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
  do {\
    ANNOTATE_IGNORE_READS_BEGIN();\
    ANNOTATE_IGNORE_WRITES_BEGIN();\
  }while(0)\

// Stop ignoring all memory accesses.
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() \
  do {\
    ANNOTATE_IGNORE_WRITES_END();\
    ANNOTATE_IGNORE_READS_END();\
  }while(0)\

// -------------------------------------------------------------
// Annotations useful for debugging.

// Request to trace every access to "address".
#define ANNOTATE_TRACE_MEMORY(address) \
  AnnotateTraceMemory(__FILE__, __LINE__, address)

// Report the current thread name to a race detector.
#define ANNOTATE_THREAD_NAME(name) \
  AnnotateThreadName(__FILE__, __LINE__, name)

// -------------------------------------------------------------
// Annotations useful when implementing locks.  They are not
// normally needed by modules that merely use locks.
// The "lock" argument is a pointer to the lock object.

// Report that a lock has been created at address "lock".
#define ANNOTATE_RWLOCK_CREATE(lock) \
  AnnotateRWLockCreate(__FILE__, __LINE__, lock)

// Report that the lock at address "lock" is about to be destroyed.
#define ANNOTATE_RWLOCK_DESTROY(lock) \
  AnnotateRWLockDestroy(__FILE__, __LINE__, lock)

// Report that the lock at address "lock" has been acquired.
// is_w=1 for writer lock, is_w=0 for reader lock.
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) \
  AnnotateRWLockAcquired(__FILE__, __LINE__, lock, is_w)

// Report that the lock at address "lock" is about to be released.
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
  AnnotateRWLockReleased(__FILE__, __LINE__, lock, is_w)

// -------------------------------------------------------------
// Annotations useful for testing race detectors.

// Report that we expect a race on the variable at "address".
// Use only in unit tests for a race detector.
#define ANNOTATE_EXPECT_RACE(address, description) \
  AnnotateExpectRace(__FILE__, __LINE__, address, description)

// A no-op. Insert where you like to test the interceptors.
#define ANNOTATE_NO_OP(arg) \
  AnnotateNoOp(__FILE__, __LINE__, arg)

// Use the macros above rather than using these functions directly.
extern "C" void AnnotateRWLockCreate(const char *file, int line,
                                     const volatile void *lock);
extern "C" void AnnotateRWLockDestroy(const char *file, int line,
                                      const volatile void *lock);
extern "C" void AnnotateRWLockAcquired(const char *file, int line,
                                       const volatile void *lock, long is_w);
extern "C" void AnnotateRWLockReleased(const char *file, int line,
                                       const volatile void *lock, long is_w);
extern "C" void AnnotateCondVarWait(const char *file, int line,
                                    const volatile void *cv,
                                    const volatile void *lock);
extern "C" void AnnotateCondVarSignal(const char *file, int line,
                                      const volatile void *cv);
extern "C" void AnnotateCondVarSignalAll(const char *file, int line,
                                         const volatile void *cv);
extern "C" void AnnotatePublishMemoryRange(const char *file, int line,
                                           const volatile void *address,
                                           long size);
extern "C" void AnnotatePCQCreate(const char *file, int line,
                                  const volatile void *pcq);
extern "C" void AnnotatePCQDestroy(const char *file, int line,
                                   const volatile void *pcq);
extern "C" void AnnotatePCQPut(const char *file, int line,
                               const volatile void *pcq);
extern "C" void AnnotatePCQGet(const char *file, int line,
                               const volatile void *pcq);
extern "C" void AnnotateNewMemory(const char *file, int line,
                                  const volatile void *address,
                                  long size);
extern "C" void AnnotateExpectRace(const char *file, int line,
                                   const volatile void *address,
                                   const char *description);
extern "C" void AnnotateBenignRace(const char *file, int line,
                                   const volatile void *address,
                                   const char *description);
extern "C" void AnnotateMutexIsUsedAsCondVar(const char *file, int line,
                                            const volatile void *mu);
extern "C" void AnnotateTraceMemory(const char *file, int line,
                                    const volatile void *arg);
extern "C" void AnnotateThreadName(const char *file, int line,
                                   const char *name);
extern "C" void AnnotateIgnoreReadsBegin(const char *file, int line);
extern "C" void AnnotateIgnoreReadsEnd(const char *file, int line);
extern "C" void AnnotateIgnoreWritesBegin(const char *file, int line);
extern "C" void AnnotateIgnoreWritesEnd(const char *file, int line);
extern "C" void AnnotateNoOp(const char *file, int line,
                             const volatile void *arg);

// ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
//
// Instead of doing
//    ANNOTATE_IGNORE_READS_BEGIN();
//    ... = x;
//    ANNOTATE_IGNORE_READS_END();
// one can use
//    ... = ANNOTATE_UNPROTECTED_READ(x);
template <class T>
inline T ANNOTATE_UNPROTECTED_READ(const volatile T &x) {
  ANNOTATE_IGNORE_READS_BEGIN();
  T res = x;
  ANNOTATE_IGNORE_READS_END();
  return res;
}

// Apply ANNOTATE_BENIGN_RACE to a static variable.
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description)        \
  namespace {                                                       \
    class static_var ## _annotator {                                \
     public:                                                        \
      static_var ## _annotator() {                                  \
        ANNOTATE_BENIGN_RACE(&static_var,                           \
          # static_var ": " description);                           \
      }                                                             \
    };                                                              \
    static static_var ## _annotator the ## static_var ## _annotator;\
  }

#else
// NVALGRIND is defined, empty macros.

#define ANNOTATE_RWLOCK_CREATE(lock) // empty
#define ANNOTATE_RWLOCK_DESTROY(lock) // empty
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) // empty
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) // empty
#define ANNOTATE_CONDVAR_LOCK_WAIT(cv, lock) // empty
#define ANNOTATE_CONDVAR_WAIT(cv) // empty
#define ANNOTATE_CONDVAR_SIGNAL(cv) // empty
#define ANNOTATE_CONDVAR_SIGNAL_ALL(cv) // empty
#define ANNOTATE_HAPPENS_BEFORE(obj) // empty
#define ANNOTATE_HAPPENS_AFTER(obj) // empty
#define ANNOTATE_PUBLISH_MEMORY_RANGE(address, size) // empty
#define ANNOTATE_PUBLISH_OBJECT(address) // empty
#define ANNOTATE_PCQ_CREATE(pcq) // empty
#define ANNOTATE_PCQ_DESTROY(pcq) // empty
#define ANNOTATE_PCQ_PUT(pcq) // empty
#define ANNOTATE_PCQ_GET(pcq) // empty
#define ANNOTATE_NEW_MEMORY(address, size) // empty
#define ANNOTATE_EXPECT_RACE(address, description) // empty
#define ANNOTATE_BENIGN_RACE(address, description) // empty
#define ANNOTATE_MUTEX_IS_USED_AS_CONDVAR(mu) // empty
#define ANNOTATE_TRACE_MEMORY(arg) // empty
#define ANNOTATE_THREAD_NAME(name) // empty
#define ANNOTATE_IGNORE_READS_BEGIN() // empty
#define ANNOTATE_IGNORE_READS_END() // empty
#define ANNOTATE_IGNORE_WRITES_BEGIN() // empty
#define ANNOTATE_IGNORE_WRITES_END() // empty
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() // empty
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() // empty
#define ANNOTATE_NO_OP(arg) // empty
#define ANNOTATE_UNPROTECTED_READ(x) (x)
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description)  // empty

#endif  // NVALGRIND

// Return non-zero value if running under valgrind.
extern "C" int RunningOnValgrind();

#endif  // BASE_DYNAMIC_ANNOTATIONS_H_