src/mutex.cc - LeafOS-Project/android_art - Gitiles

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "mutex.h"

 #include <errno.h>

 #include "logging.h"
 #include "runtime.h"
 #include "thread.h"
 #include "utils.h"

 #if defined(__APPLE__)
 #include "AvailabilityMacros.h" // For MAC_OS_X_VERSION_MAX_ALLOWED
 #endif

 #define CHECK_MUTEX_CALL(call, args) CHECK_PTHREAD_CALL(call, args, name_)

 extern int pthread_mutex_lock(pthread_mutex_t* mutex) EXCLUSIVE_LOCK_FUNCTION(mutex);
 extern int pthread_mutex_unlock(pthread_mutex_t* mutex) UNLOCK_FUNCTION(1);
 extern int pthread_mutex_trylock(pthread_mutex_t* mutex) EXCLUSIVE_TRYLOCK_FUNCTION(0, mutex);

 namespace art {

 // This works on Mac OS 10.6 but hasn't been tested on older releases.
 struct __attribute__((__may_alias__)) darwin_pthread_mutex_t {
   long padding0;
   int padding1;
   uint32_t padding2;
   int16_t padding3;
   int16_t padding4;
   uint32_t padding5;
   pthread_t darwin_pthread_mutex_owner;
   // ...other stuff we don't care about.
 };

 struct __attribute__((__may_alias__)) darwin_pthread_rwlock_t {
   long padding0;
   pthread_mutex_t padding1;
   int padding2;
   pthread_cond_t padding3;
   pthread_cond_t padding4;
   int padding5;
   int padding6;
   pthread_t darwin_pthread_rwlock_owner;
   // ...other stuff we don't care about.
 };

 struct __attribute__((__may_alias__)) glibc_pthread_mutex_t {
   int32_t padding0[2];
   int owner;
   // ...other stuff we don't care about.
 };

 struct __attribute__((__may_alias__)) glibc_pthread_rwlock_t {
 #ifdef __LP64__
   int32_t padding0[6];
 #else
   int32_t padding0[7];
 #endif
   int writer;
   // ...other stuff we don't care about.
 };

 ReaderWriterMutex* Locks::mutator_lock_ = NULL;
 Mutex* Locks::thread_list_lock_ = NULL;
 Mutex* Locks::classlinker_classes_lock_ = NULL;
 ReaderWriterMutex* Locks::heap_bitmap_lock_ = NULL;
 Mutex* Locks::abort_lock_ = NULL;
 Mutex* Locks::logging_lock_ = NULL;
 Mutex* Locks::unexpected_signal_lock_ = NULL;
 Mutex* Locks::thread_suspend_count_lock_ = NULL;

 void Locks::Init() {
   if (logging_lock_ != NULL) {
     // Already initialized.
     DCHECK(mutator_lock_ != NULL);
     DCHECK(thread_list_lock_ != NULL);
     DCHECK(classlinker_classes_lock_ != NULL);
     DCHECK(heap_bitmap_lock_ != NULL);
     DCHECK(abort_lock_ != NULL);
     DCHECK(logging_lock_ != NULL);
     DCHECK(unexpected_signal_lock_ != NULL);
     DCHECK(thread_suspend_count_lock_ != NULL);
   } else {
     logging_lock_ = new Mutex("logging lock", kLoggingLock, true);
     abort_lock_ = new Mutex("abort lock", kAbortLock, true);
     DCHECK(mutator_lock_ == NULL);
     mutator_lock_ = new ReaderWriterMutex("mutator lock", kMutatorLock);
     DCHECK(thread_list_lock_ == NULL);
     thread_list_lock_ = new Mutex("thread list lock", kThreadListLock);
     DCHECK(classlinker_classes_lock_ == NULL);
     classlinker_classes_lock_ = new Mutex("ClassLinker classes lock", kClassLinkerClassesLock);
     DCHECK(heap_bitmap_lock_ == NULL);
     heap_bitmap_lock_ = new ReaderWriterMutex("heap bitmap lock", kHeapBitmapLock);
     DCHECK(unexpected_signal_lock_ == NULL);
     unexpected_signal_lock_ = new Mutex("unexpected signal lock", kUnexpectedSignalLock, true);
     DCHECK(thread_suspend_count_lock_ == NULL);
     thread_suspend_count_lock_ = new Mutex("thread suspend count lock", kThreadSuspendCountLock);
   }
 }

 BaseMutex::BaseMutex(const char* name, MutexLevel level) : level_(level), name_(name) {}

 static void CheckUnattachedThread(MutexLevel level) {
   // The check below enumerates the cases where we expect not to be able to sanity check locks
   // on a thread. TODO: tighten this check.
   if (kDebugLocking) {
     Runtime* runtime = Runtime::Current();
     CHECK(runtime == NULL || !runtime->IsStarted() || runtime->IsShuttingDown() ||
           level == kDefaultMutexLevel  || level == kThreadListLock ||
           level == kLoggingLock || level == kAbortLock);
   }
 }

 void BaseMutex::RegisterAsLockedWithCurrentThread() {
   Thread* self = Thread::Current();
   if (self == NULL) {
     CheckUnattachedThread(level_);
     return;
   }
   if (kDebugLocking) {
     // Check if a bad Mutex of this level or lower is held.
     bool bad_mutexes_held = false;
     for (int i = level_; i >= 0; --i) {
       BaseMutex* held_mutex = self->GetHeldMutex(static_cast<MutexLevel>(i));
       if (UNLIKELY(held_mutex != NULL)) {
         LOG(ERROR) << "Lock level violation: holding \"" << held_mutex->name_ << "\" (level " << i
             << ") while locking \"" << name_ << "\" (level " << static_cast<int>(level_) << ")";
         if (i > kAbortLock) {
           // Only abort in the check below if this is more than abort level lock.
           bad_mutexes_held = true;
         }
       }
     }
     CHECK(!bad_mutexes_held);
   }
   // Don't record monitors as they are outside the scope of analysis. They may be inspected off of
   // the monitor list.
   if (level_ != kMonitorLock) {
     self->SetHeldMutex(level_, this);
   }
 }

 void BaseMutex::RegisterAsUnlockedWithCurrentThread() {
   Thread* self = Thread::Current();
   if (self == NULL) {
     CheckUnattachedThread(level_);
     return;
   }
   if (level_ != kMonitorLock) {
     if (kDebugLocking) {
       CHECK(self->GetHeldMutex(level_) == this) << "Unlocking on unacquired mutex: " << name_;
     }
     self->SetHeldMutex(level_, NULL);
   }
 }

 void BaseMutex::CheckSafeToWait() {
   Thread* self = Thread::Current();
   if (self == NULL) {
     CheckUnattachedThread(level_);
     return;
   }
   if (kDebugLocking) {
     CHECK(self->GetHeldMutex(level_) == this) << "Waiting on unacquired mutex: " << name_;
     bool bad_mutexes_held = false;
     for (int i = kMaxMutexLevel; i >= 0; --i) {
       if (i != level_) {
         BaseMutex* held_mutex = self->GetHeldMutex(static_cast<MutexLevel>(i));
         if (held_mutex != NULL) {
           LOG(ERROR) << "Holding " << held_mutex->name_ << " (level " << i
               << ") while performing wait on: "
               << name_ << " (level " << static_cast<int>(level_) << ")";
           bad_mutexes_held = true;
         }
       }
     }
     CHECK(!bad_mutexes_held);
   }
 }

 Mutex::Mutex(const char* name, MutexLevel level, bool recursive)
     : BaseMutex(name, level), recursive_(recursive), recursion_count_(0) {
 #if defined(__BIONIC__) || defined(__APPLE__)
   // Use recursive mutexes for bionic and Apple otherwise the
   // non-recursive mutexes don't have TIDs to check lock ownership of.
   pthread_mutexattr_t attributes;
   CHECK_MUTEX_CALL(pthread_mutexattr_init, (&attributes));
   CHECK_MUTEX_CALL(pthread_mutexattr_settype, (&attributes, PTHREAD_MUTEX_RECURSIVE));
   CHECK_MUTEX_CALL(pthread_mutex_init, (&mutex_, &attributes));
   CHECK_MUTEX_CALL(pthread_mutexattr_destroy, (&attributes));
 #else
   CHECK_MUTEX_CALL(pthread_mutex_init, (&mutex_, NULL));
 #endif
 }

 Mutex::~Mutex() {
   // We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
   // may still be using locks.
   int rc = pthread_mutex_destroy(&mutex_);
   if (rc != 0) {
     errno = rc;
     // TODO: should we just not log at all if shutting down? this could be the logging mutex!
     bool shutting_down = Runtime::Current()->IsShuttingDown();
     PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
   }
 }

 void Mutex::ExclusiveLock() {
   if (kDebugLocking && !recursive_) {
     AssertNotHeld();
   }
   if (!recursive_ || !IsExclusiveHeld()) {
     CHECK_MUTEX_CALL(pthread_mutex_lock, (&mutex_));
     RegisterAsLockedWithCurrentThread();
   }
   recursion_count_++;
   if (kDebugLocking) {
     CHECK(recursion_count_ == 1 || recursive_) << "Unexpected recursion count on mutex: "
         << name_ << " " << recursion_count_;
     AssertHeld();
   }
 }

 bool Mutex::ExclusiveTryLock() {
   if (kDebugLocking && !recursive_) {
     AssertNotHeld();
   }
   if (!recursive_ || !IsExclusiveHeld()) {
     int result = pthread_mutex_trylock(&mutex_);
     if (result == EBUSY) {
       return false;
     }
     if (result != 0) {
       errno = result;
       PLOG(FATAL) << "pthread_mutex_trylock failed for " << name_;
     }
     RegisterAsLockedWithCurrentThread();
   }
   recursion_count_++;
   if (kDebugLocking) {
     CHECK(recursion_count_ == 1 || recursive_) << "Unexpected recursion count on mutex: "
         << name_ << " " << recursion_count_;
     AssertHeld();
   }
   return true;
 }

 void Mutex::ExclusiveUnlock() {
   AssertHeld();
   recursion_count_--;
   if (!recursive_ || recursion_count_ == 0) {
     if (kDebugLocking) {
       CHECK(recursion_count_ == 0 || recursive_) << "Unexpected recursion count on mutex: "
           << name_ << " " << recursion_count_;
     }
     RegisterAsUnlockedWithCurrentThread();
     CHECK_MUTEX_CALL(pthread_mutex_unlock, (&mutex_));
   }
 }

 bool Mutex::IsExclusiveHeld() const {
   Thread* self = Thread::Current();
   bool result;
   if (self == NULL || level_ == kMonitorLock) {  // Handle unattached threads and monitors.
     result = (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid()));
   } else {
     result = (self->GetHeldMutex(level_) == this);
     // Sanity debug check that if we think it is locked, so does the pthread.
     if (kDebugLocking) {
       CHECK(result == (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid())));
     }
   }
   return result;
 }

 uint64_t Mutex::GetExclusiveOwnerTid() const {
 #if defined(__BIONIC__)
   return static_cast<uint64_t>((mutex_.value >> 16) & 0xffff);
 #elif defined(__GLIBC__)
   return reinterpret_cast<const glibc_pthread_mutex_t*>(&mutex_)->owner;
 #elif defined(__APPLE__)
   const darwin_pthread_mutex_t* dpmutex = reinterpret_cast<const darwin_pthread_mutex_t*>(&mutex_);
   pthread_t owner = dpmutex->darwin_pthread_mutex_owner;
   // 0 for unowned, -1 for PTHREAD_MTX_TID_SWITCHING
   // TODO: should we make darwin_pthread_mutex_owner volatile and recheck until not -1?
   if ((owner == (pthread_t)0) || (owner == (pthread_t)-1)) {
     return 0;
   }
   uint64_t tid;
   CHECK_PTHREAD_CALL(pthread_threadid_np, (owner, &tid), __FUNCTION__);  // Requires Mac OS 10.6
   return tid;
 #else
 #error unsupported C library
 #endif
 }

 ReaderWriterMutex::ReaderWriterMutex(const char* name, MutexLevel level) : BaseMutex(name, level) {
   CHECK_MUTEX_CALL(pthread_rwlock_init, (&rwlock_, NULL));
 }

 ReaderWriterMutex::~ReaderWriterMutex() {
   // We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
   // may still be using locks.
   int rc = pthread_rwlock_destroy(&rwlock_);
   if (rc != 0) {
     errno = rc;
     // TODO: should we just not log at all if shutting down? this could be the logging mutex!
     bool shutting_down = Runtime::Current()->IsShuttingDown();
     PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
   }
 }

 void ReaderWriterMutex::ExclusiveLock() {
   AssertNotExclusiveHeld();
   CHECK_MUTEX_CALL(pthread_rwlock_wrlock, (&rwlock_));
   RegisterAsLockedWithCurrentThread();
   AssertExclusiveHeld();
 }

 void ReaderWriterMutex::ExclusiveUnlock() {
   AssertExclusiveHeld();
   RegisterAsUnlockedWithCurrentThread();
   CHECK_MUTEX_CALL(pthread_rwlock_unlock, (&rwlock_));
 }

 #if HAVE_TIMED_RWLOCK
 bool ReaderWriterMutex::ExclusiveLockWithTimeout(const timespec& abs_timeout) {
   int result = pthread_rwlock_timedwrlock(&rwlock_, &abs_timeout);
   if (result == ETIMEDOUT) {
     return false;
   }
   if (result != 0) {
     errno = result;
     PLOG(FATAL) << "pthread_rwlock_timedwrlock failed for " << name_;
   }
   RegisterAsLockedWithCurrentThread();
   AssertSharedHeld();
   return true;
 }
 #endif

 void ReaderWriterMutex::SharedLock() {
   CHECK_MUTEX_CALL(pthread_rwlock_rdlock, (&rwlock_));
   RegisterAsLockedWithCurrentThread();
   AssertSharedHeld();
 }

 bool ReaderWriterMutex::SharedTryLock() {
   int result = pthread_rwlock_tryrdlock(&rwlock_);
   if (result == EBUSY) {
     return false;
   }
   if (result != 0) {
     errno = result;
     PLOG(FATAL) << "pthread_mutex_trylock failed for " << name_;
   }
   RegisterAsLockedWithCurrentThread();
   AssertSharedHeld();
   return true;
 }

 void ReaderWriterMutex::SharedUnlock() {
   AssertSharedHeld();
   RegisterAsUnlockedWithCurrentThread();
   CHECK_MUTEX_CALL(pthread_rwlock_unlock, (&rwlock_));
 }

 bool ReaderWriterMutex::IsExclusiveHeld() const {
   bool result = (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid()));
   if (kDebugLocking) {
     // Sanity that if the pthread thinks we own the lock the Thread agrees.
     Thread* self = Thread::Current();
     CHECK((self == NULL) || !result || (self->GetHeldMutex(level_) == this));
   }
   return result;
 }

 bool ReaderWriterMutex::IsSharedHeld() const {
   Thread* self = Thread::Current();
   bool result;
   if (UNLIKELY(self == NULL)) {  // Handle unattached threads.
     result = IsExclusiveHeld(); // TODO: a better best effort here.
   } else {
     result = (self->GetHeldMutex(level_) == this);
   }
   return result;
 }

 uint64_t ReaderWriterMutex::GetExclusiveOwnerTid() const {
 #if defined(__BIONIC__)
   return rwlock_.writerThreadId;
 #elif defined(__GLIBC__)
   return reinterpret_cast<const glibc_pthread_rwlock_t*>(&rwlock_)->writer;
 #elif defined(__APPLE__)
   const darwin_pthread_rwlock_t* dprwlock = reinterpret_cast<const darwin_pthread_rwlock_t*>(&rwlock_);
   pthread_t owner = dprwlock->darwin_pthread_rwlock_owner;
   if (owner == (pthread_t)0) {
     return 0;
   }
   uint64_t tid;
   CHECK_PTHREAD_CALL(pthread_threadid_np, (owner, &tid), __FUNCTION__);  // Requires Mac OS 10.6
   return tid;
 #else
 #error unsupported C library
 #endif
 }

 ConditionVariable::ConditionVariable(const std::string& name) : name_(name) {
   CHECK_MUTEX_CALL(pthread_cond_init, (&cond_, NULL));
 }

 ConditionVariable::~ConditionVariable() {
   // We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
   // may still be using condition variables.
   int rc = pthread_cond_destroy(&cond_);
   if (rc != 0) {
     errno = rc;
     bool shutting_down = Runtime::Current()->IsShuttingDown();
     PLOG(shutting_down ? WARNING : FATAL) << "pthread_cond_destroy failed for " << name_;
   }
 }

 void ConditionVariable::Broadcast() {
   CHECK_MUTEX_CALL(pthread_cond_broadcast, (&cond_));
 }

 void ConditionVariable::Signal() {
   CHECK_MUTEX_CALL(pthread_cond_signal, (&cond_));
 }

 void ConditionVariable::Wait(Mutex& mutex) {
   mutex.CheckSafeToWait();
   unsigned int old_recursion_count = mutex.recursion_count_;
   mutex.recursion_count_ = 0;
   CHECK_MUTEX_CALL(pthread_cond_wait, (&cond_, &mutex.mutex_));
   mutex.recursion_count_ = old_recursion_count;
 }

 void ConditionVariable::TimedWait(Mutex& mutex, const timespec& ts) {
 #ifdef HAVE_TIMEDWAIT_MONOTONIC
 #define TIMEDWAIT pthread_cond_timedwait_monotonic
 #else
 #define TIMEDWAIT pthread_cond_timedwait
 #endif
   mutex.CheckSafeToWait();
   unsigned int old_recursion_count = mutex.recursion_count_;
   mutex.recursion_count_ = 0;
   int rc = TIMEDWAIT(&cond_, &mutex.mutex_, &ts);
   mutex.recursion_count_ = old_recursion_count;
   if (rc != 0 && rc != ETIMEDOUT) {
     errno = rc;
     PLOG(FATAL) << "TimedWait failed for " << name_;
   }
 }

 }  // namespace art
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "mutex.h"

	#include <errno.h>

	#include "logging.h"
	#include "runtime.h"
	#include "thread.h"
	#include "utils.h"

	#if defined(__APPLE__)
	#include "AvailabilityMacros.h" // For MAC_OS_X_VERSION_MAX_ALLOWED
	#endif

	#define CHECK_MUTEX_CALL(call, args) CHECK_PTHREAD_CALL(call, args, name_)

	extern int pthread_mutex_lock(pthread_mutex_t* mutex) EXCLUSIVE_LOCK_FUNCTION(mutex);
	extern int pthread_mutex_unlock(pthread_mutex_t* mutex) UNLOCK_FUNCTION(1);
	extern int pthread_mutex_trylock(pthread_mutex_t* mutex) EXCLUSIVE_TRYLOCK_FUNCTION(0, mutex);

	namespace art {

	// This works on Mac OS 10.6 but hasn't been tested on older releases.
	struct __attribute__((__may_alias__)) darwin_pthread_mutex_t {
	long padding0;
	int padding1;
	uint32_t padding2;
	int16_t padding3;
	int16_t padding4;
	uint32_t padding5;
	pthread_t darwin_pthread_mutex_owner;
	// ...other stuff we don't care about.
	};

	struct __attribute__((__may_alias__)) darwin_pthread_rwlock_t {
	long padding0;
	pthread_mutex_t padding1;
	int padding2;
	pthread_cond_t padding3;
	pthread_cond_t padding4;
	int padding5;
	int padding6;
	pthread_t darwin_pthread_rwlock_owner;
	// ...other stuff we don't care about.
	};

	struct __attribute__((__may_alias__)) glibc_pthread_mutex_t {
	int32_t padding0[2];
	int owner;
	// ...other stuff we don't care about.
	};

	struct __attribute__((__may_alias__)) glibc_pthread_rwlock_t {
	#ifdef __LP64__
	int32_t padding0[6];
	#else
	int32_t padding0[7];
	#endif
	int writer;
	// ...other stuff we don't care about.
	};

	ReaderWriterMutex* Locks::mutator_lock_ = NULL;
	Mutex* Locks::thread_list_lock_ = NULL;
	Mutex* Locks::classlinker_classes_lock_ = NULL;
	ReaderWriterMutex* Locks::heap_bitmap_lock_ = NULL;
	Mutex* Locks::abort_lock_ = NULL;
	Mutex* Locks::logging_lock_ = NULL;
	Mutex* Locks::unexpected_signal_lock_ = NULL;
	Mutex* Locks::thread_suspend_count_lock_ = NULL;

	void Locks::Init() {
	if (logging_lock_ != NULL) {
	// Already initialized.
	DCHECK(mutator_lock_ != NULL);
	DCHECK(thread_list_lock_ != NULL);
	DCHECK(classlinker_classes_lock_ != NULL);
	DCHECK(heap_bitmap_lock_ != NULL);
	DCHECK(abort_lock_ != NULL);
	DCHECK(logging_lock_ != NULL);
	DCHECK(unexpected_signal_lock_ != NULL);
	DCHECK(thread_suspend_count_lock_ != NULL);
	} else {
	logging_lock_ = new Mutex("logging lock", kLoggingLock, true);
	abort_lock_ = new Mutex("abort lock", kAbortLock, true);
	DCHECK(mutator_lock_ == NULL);
	mutator_lock_ = new ReaderWriterMutex("mutator lock", kMutatorLock);
	DCHECK(thread_list_lock_ == NULL);
	thread_list_lock_ = new Mutex("thread list lock", kThreadListLock);
	DCHECK(classlinker_classes_lock_ == NULL);
	classlinker_classes_lock_ = new Mutex("ClassLinker classes lock", kClassLinkerClassesLock);
	DCHECK(heap_bitmap_lock_ == NULL);
	heap_bitmap_lock_ = new ReaderWriterMutex("heap bitmap lock", kHeapBitmapLock);
	DCHECK(unexpected_signal_lock_ == NULL);
	unexpected_signal_lock_ = new Mutex("unexpected signal lock", kUnexpectedSignalLock, true);
	DCHECK(thread_suspend_count_lock_ == NULL);
	thread_suspend_count_lock_ = new Mutex("thread suspend count lock", kThreadSuspendCountLock);
	}
	}

	BaseMutex::BaseMutex(const char* name, MutexLevel level) : level_(level), name_(name) {}

	static void CheckUnattachedThread(MutexLevel level) {
	// The check below enumerates the cases where we expect not to be able to sanity check locks
	// on a thread. TODO: tighten this check.
	if (kDebugLocking) {
	Runtime* runtime = Runtime::Current();
	CHECK(runtime == NULL \|\| !runtime->IsStarted() \|\| runtime->IsShuttingDown() \|\|
	level == kDefaultMutexLevel \|\| level == kThreadListLock \|\|
	level == kLoggingLock \|\| level == kAbortLock);
	}
	}

	void BaseMutex::RegisterAsLockedWithCurrentThread() {
	Thread* self = Thread::Current();
	if (self == NULL) {
	CheckUnattachedThread(level_);
	return;
	}
	if (kDebugLocking) {
	// Check if a bad Mutex of this level or lower is held.
	bool bad_mutexes_held = false;
	for (int i = level_; i >= 0; --i) {
	BaseMutex* held_mutex = self->GetHeldMutex(static_cast<MutexLevel>(i));
	if (UNLIKELY(held_mutex != NULL)) {
	LOG(ERROR) << "Lock level violation: holding \"" << held_mutex->name_ << "\" (level " << i
	<< ") while locking \"" << name_ << "\" (level " << static_cast<int>(level_) << ")";
	if (i > kAbortLock) {
	// Only abort in the check below if this is more than abort level lock.
	bad_mutexes_held = true;
	}
	}
	}
	CHECK(!bad_mutexes_held);
	}
	// Don't record monitors as they are outside the scope of analysis. They may be inspected off of
	// the monitor list.
	if (level_ != kMonitorLock) {
	self->SetHeldMutex(level_, this);
	}
	}

	void BaseMutex::RegisterAsUnlockedWithCurrentThread() {
	Thread* self = Thread::Current();
	if (self == NULL) {
	CheckUnattachedThread(level_);
	return;
	}
	if (level_ != kMonitorLock) {
	if (kDebugLocking) {
	CHECK(self->GetHeldMutex(level_) == this) << "Unlocking on unacquired mutex: " << name_;
	}
	self->SetHeldMutex(level_, NULL);
	}
	}

	void BaseMutex::CheckSafeToWait() {
	Thread* self = Thread::Current();
	if (self == NULL) {
	CheckUnattachedThread(level_);
	return;
	}
	if (kDebugLocking) {
	CHECK(self->GetHeldMutex(level_) == this) << "Waiting on unacquired mutex: " << name_;
	bool bad_mutexes_held = false;
	for (int i = kMaxMutexLevel; i >= 0; --i) {
	if (i != level_) {
	BaseMutex* held_mutex = self->GetHeldMutex(static_cast<MutexLevel>(i));
	if (held_mutex != NULL) {
	LOG(ERROR) << "Holding " << held_mutex->name_ << " (level " << i
	<< ") while performing wait on: "
	<< name_ << " (level " << static_cast<int>(level_) << ")";
	bad_mutexes_held = true;
	}
	}
	}
	CHECK(!bad_mutexes_held);
	}
	}

	Mutex::Mutex(const char* name, MutexLevel level, bool recursive)
	: BaseMutex(name, level), recursive_(recursive), recursion_count_(0) {
	#if defined(__BIONIC__) \|\| defined(__APPLE__)
	// Use recursive mutexes for bionic and Apple otherwise the
	// non-recursive mutexes don't have TIDs to check lock ownership of.
	pthread_mutexattr_t attributes;
	CHECK_MUTEX_CALL(pthread_mutexattr_init, (&attributes));
	CHECK_MUTEX_CALL(pthread_mutexattr_settype, (&attributes, PTHREAD_MUTEX_RECURSIVE));
	CHECK_MUTEX_CALL(pthread_mutex_init, (&mutex_, &attributes));
	CHECK_MUTEX_CALL(pthread_mutexattr_destroy, (&attributes));
	#else
	CHECK_MUTEX_CALL(pthread_mutex_init, (&mutex_, NULL));
	#endif
	}

	Mutex::~Mutex() {
	// We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
	// may still be using locks.
	int rc = pthread_mutex_destroy(&mutex_);
	if (rc != 0) {
	errno = rc;
	// TODO: should we just not log at all if shutting down? this could be the logging mutex!
	bool shutting_down = Runtime::Current()->IsShuttingDown();
	PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
	}
	}

	void Mutex::ExclusiveLock() {
	if (kDebugLocking && !recursive_) {
	AssertNotHeld();
	}
	if (!recursive_ \|\| !IsExclusiveHeld()) {
	CHECK_MUTEX_CALL(pthread_mutex_lock, (&mutex_));
	RegisterAsLockedWithCurrentThread();
	}
	recursion_count_++;
	if (kDebugLocking) {
	CHECK(recursion_count_ == 1 \|\| recursive_) << "Unexpected recursion count on mutex: "
	<< name_ << " " << recursion_count_;
	AssertHeld();
	}
	}

	bool Mutex::ExclusiveTryLock() {
	if (kDebugLocking && !recursive_) {
	AssertNotHeld();
	}
	if (!recursive_ \|\| !IsExclusiveHeld()) {
	int result = pthread_mutex_trylock(&mutex_);
	if (result == EBUSY) {
	return false;
	}
	if (result != 0) {
	errno = result;
	PLOG(FATAL) << "pthread_mutex_trylock failed for " << name_;
	}
	RegisterAsLockedWithCurrentThread();
	}
	recursion_count_++;
	if (kDebugLocking) {
	CHECK(recursion_count_ == 1 \|\| recursive_) << "Unexpected recursion count on mutex: "
	<< name_ << " " << recursion_count_;
	AssertHeld();
	}
	return true;
	}

	void Mutex::ExclusiveUnlock() {
	AssertHeld();
	recursion_count_--;
	if (!recursive_ \|\| recursion_count_ == 0) {
	if (kDebugLocking) {
	CHECK(recursion_count_ == 0 \|\| recursive_) << "Unexpected recursion count on mutex: "
	<< name_ << " " << recursion_count_;
	}
	RegisterAsUnlockedWithCurrentThread();
	CHECK_MUTEX_CALL(pthread_mutex_unlock, (&mutex_));
	}
	}

	bool Mutex::IsExclusiveHeld() const {
	Thread* self = Thread::Current();
	bool result;
	if (self == NULL \|\| level_ == kMonitorLock) { // Handle unattached threads and monitors.
	result = (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid()));
	} else {
	result = (self->GetHeldMutex(level_) == this);
	// Sanity debug check that if we think it is locked, so does the pthread.
	if (kDebugLocking) {
	CHECK(result == (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid())));
	}
	}
	return result;
	}

	uint64_t Mutex::GetExclusiveOwnerTid() const {
	#if defined(__BIONIC__)
	return static_cast<uint64_t>((mutex_.value >> 16) & 0xffff);
	#elif defined(__GLIBC__)
	return reinterpret_cast<const glibc_pthread_mutex_t*>(&mutex_)->owner;
	#elif defined(__APPLE__)
	const darwin_pthread_mutex_t* dpmutex = reinterpret_cast<const darwin_pthread_mutex_t*>(&mutex_);
	pthread_t owner = dpmutex->darwin_pthread_mutex_owner;
	// 0 for unowned, -1 for PTHREAD_MTX_TID_SWITCHING
	// TODO: should we make darwin_pthread_mutex_owner volatile and recheck until not -1?
	if ((owner == (pthread_t)0) \|\| (owner == (pthread_t)-1)) {
	return 0;
	}
	uint64_t tid;
	CHECK_PTHREAD_CALL(pthread_threadid_np, (owner, &tid), __FUNCTION__); // Requires Mac OS 10.6
	return tid;
	#else
	#error unsupported C library
	#endif
	}

	ReaderWriterMutex::ReaderWriterMutex(const char* name, MutexLevel level) : BaseMutex(name, level) {
	CHECK_MUTEX_CALL(pthread_rwlock_init, (&rwlock_, NULL));
	}

	ReaderWriterMutex::~ReaderWriterMutex() {
	// We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
	// may still be using locks.
	int rc = pthread_rwlock_destroy(&rwlock_);
	if (rc != 0) {
	errno = rc;
	// TODO: should we just not log at all if shutting down? this could be the logging mutex!
	bool shutting_down = Runtime::Current()->IsShuttingDown();
	PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
	}
	}

	void ReaderWriterMutex::ExclusiveLock() {
	AssertNotExclusiveHeld();
	CHECK_MUTEX_CALL(pthread_rwlock_wrlock, (&rwlock_));
	RegisterAsLockedWithCurrentThread();
	AssertExclusiveHeld();
	}

	void ReaderWriterMutex::ExclusiveUnlock() {
	AssertExclusiveHeld();
	RegisterAsUnlockedWithCurrentThread();
	CHECK_MUTEX_CALL(pthread_rwlock_unlock, (&rwlock_));
	}

	#if HAVE_TIMED_RWLOCK
	bool ReaderWriterMutex::ExclusiveLockWithTimeout(const timespec& abs_timeout) {
	int result = pthread_rwlock_timedwrlock(&rwlock_, &abs_timeout);
	if (result == ETIMEDOUT) {
	return false;
	}
	if (result != 0) {
	errno = result;
	PLOG(FATAL) << "pthread_rwlock_timedwrlock failed for " << name_;
	}
	RegisterAsLockedWithCurrentThread();
	AssertSharedHeld();
	return true;
	}
	#endif

	void ReaderWriterMutex::SharedLock() {
	CHECK_MUTEX_CALL(pthread_rwlock_rdlock, (&rwlock_));
	RegisterAsLockedWithCurrentThread();
	AssertSharedHeld();
	}

	bool ReaderWriterMutex::SharedTryLock() {
	int result = pthread_rwlock_tryrdlock(&rwlock_);
	if (result == EBUSY) {
	return false;
	}
	if (result != 0) {
	errno = result;
	PLOG(FATAL) << "pthread_mutex_trylock failed for " << name_;
	}
	RegisterAsLockedWithCurrentThread();
	AssertSharedHeld();
	return true;
	}

	void ReaderWriterMutex::SharedUnlock() {
	AssertSharedHeld();
	RegisterAsUnlockedWithCurrentThread();
	CHECK_MUTEX_CALL(pthread_rwlock_unlock, (&rwlock_));
	}

	bool ReaderWriterMutex::IsExclusiveHeld() const {
	bool result = (GetExclusiveOwnerTid() == static_cast<uint64_t>(GetTid()));
	if (kDebugLocking) {
	// Sanity that if the pthread thinks we own the lock the Thread agrees.
	Thread* self = Thread::Current();
	CHECK((self == NULL) \|\| !result \|\| (self->GetHeldMutex(level_) == this));
	}
	return result;
	}

	bool ReaderWriterMutex::IsSharedHeld() const {
	Thread* self = Thread::Current();
	bool result;
	if (UNLIKELY(self == NULL)) { // Handle unattached threads.
	result = IsExclusiveHeld(); // TODO: a better best effort here.
	} else {
	result = (self->GetHeldMutex(level_) == this);
	}
	return result;
	}

	uint64_t ReaderWriterMutex::GetExclusiveOwnerTid() const {
	#if defined(__BIONIC__)
	return rwlock_.writerThreadId;
	#elif defined(__GLIBC__)
	return reinterpret_cast<const glibc_pthread_rwlock_t*>(&rwlock_)->writer;
	#elif defined(__APPLE__)
	const darwin_pthread_rwlock_t* dprwlock = reinterpret_cast<const darwin_pthread_rwlock_t*>(&rwlock_);
	pthread_t owner = dprwlock->darwin_pthread_rwlock_owner;
	if (owner == (pthread_t)0) {
	return 0;
	}
	uint64_t tid;
	CHECK_PTHREAD_CALL(pthread_threadid_np, (owner, &tid), __FUNCTION__); // Requires Mac OS 10.6
	return tid;
	#else
	#error unsupported C library
	#endif
	}

	ConditionVariable::ConditionVariable(const std::string& name) : name_(name) {
	CHECK_MUTEX_CALL(pthread_cond_init, (&cond_, NULL));
	}

	ConditionVariable::~ConditionVariable() {
	// We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
	// may still be using condition variables.
	int rc = pthread_cond_destroy(&cond_);
	if (rc != 0) {
	errno = rc;
	bool shutting_down = Runtime::Current()->IsShuttingDown();
	PLOG(shutting_down ? WARNING : FATAL) << "pthread_cond_destroy failed for " << name_;
	}
	}

	void ConditionVariable::Broadcast() {
	CHECK_MUTEX_CALL(pthread_cond_broadcast, (&cond_));
	}

	void ConditionVariable::Signal() {
	CHECK_MUTEX_CALL(pthread_cond_signal, (&cond_));
	}

	void ConditionVariable::Wait(Mutex& mutex) {
	mutex.CheckSafeToWait();
	unsigned int old_recursion_count = mutex.recursion_count_;
	mutex.recursion_count_ = 0;
	CHECK_MUTEX_CALL(pthread_cond_wait, (&cond_, &mutex.mutex_));
	mutex.recursion_count_ = old_recursion_count;
	}

	void ConditionVariable::TimedWait(Mutex& mutex, const timespec& ts) {
	#ifdef HAVE_TIMEDWAIT_MONOTONIC
	#define TIMEDWAIT pthread_cond_timedwait_monotonic
	#else
	#define TIMEDWAIT pthread_cond_timedwait
	#endif
	mutex.CheckSafeToWait();
	unsigned int old_recursion_count = mutex.recursion_count_;
	mutex.recursion_count_ = 0;
	int rc = TIMEDWAIT(&cond_, &mutex.mutex_, &ts);
	mutex.recursion_count_ = old_recursion_count;
	if (rc != 0 && rc != ETIMEDOUT) {
	errno = rc;
	PLOG(FATAL) << "TimedWait failed for " << name_;
	}
	}

	} // namespace art