/*
* This implements java.lang.Thread.sleep(long msec, int nsec).
*
* The sleep is interruptible by other threads, which means we can't just
* plop into an OS sleep call. (We probably could if we wanted to send
* signals around and rely on EINTR, but that's inefficient and relies
* on native code respecting our signal mask.)
*
* We have to do all of this stuff for Object.wait() as well, so it's
* easiest to just sleep on a private Monitor.
*
* It appears that we want sleep(0,0) to go through the motions of sleeping
* for a very short duration, rather than just returning.
*/
void dvmThreadSleep(u8 msec, u4 nsec)
{
Thread* self = dvmThreadSelf();
Monitor* mon = gDvm.threadSleepMon;
/* sleep(0,0) wakes up immediately, wait(0,0) means wait forever; adjust */
if (msec == 0 && nsec == 0)
nsec++;
lockMonitor(self, mon);
waitMonitor(self, mon, msec, nsec, true);
unlockMonitor(self, mon);
}
void
DOMStorageDBThread::ThreadFunc()
{
nsresult rv = InitDatabase();
MonitorAutoLock lockMonitor(mMonitor);
if (NS_FAILED(rv)) {
mStatus = rv;
mStopIOThread = true;
return;
}
while (MOZ_LIKELY(!mStopIOThread || mPreloads.Length() || mPendingTasks.HasTasks())) {
if (MOZ_UNLIKELY(TimeUntilFlush() == 0)) {
// Flush time is up or flush has been forced, do it now.
UnscheduleFlush();
if (mPendingTasks.Prepare()) {
{
MonitorAutoUnlock unlockMonitor(mMonitor);
rv = mPendingTasks.Execute(this);
}
if (!mPendingTasks.Finalize(rv)) {
mStatus = rv;
NS_WARNING("localStorage DB access broken");
}
}
NotifyFlushCompletion();
} else if (MOZ_LIKELY(mPreloads.Length())) {
nsAutoPtr<DBOperation> op(mPreloads[0]);
mPreloads.RemoveElementAt(0);
{
MonitorAutoUnlock unlockMonitor(mMonitor);
op->PerformAndFinalize(this);
}
if (op->Type() == DBOperation::opPreloadUrgent) {
SetDefaultPriority(); // urgent preload unscheduled
}
} else if (MOZ_UNLIKELY(!mStopIOThread)) {
lockMonitor.Wait(TimeUntilFlush());
}
} // thread loop
mStatus = ShutdownDatabase();
}
/*
* Changes the shape of a monitor from thin to fat, preserving the
* internal lock state. The calling thread must own the lock.
*/
static void inflateMonitor(Thread *self, Object *obj)
{
Monitor *mon;
u4 thin;
assert(self != NULL);
assert(obj != NULL);
assert(LW_SHAPE(obj->lock) == LW_SHAPE_THIN);
assert(LW_LOCK_OWNER(obj->lock) == self->threadId);
/* Allocate and acquire a new monitor. */
mon = dvmCreateMonitor(obj);
lockMonitor(self, mon);
/* Propagate the lock state. */
thin = obj->lock;
mon->lockCount = LW_LOCK_COUNT(thin);
thin &= LW_HASH_STATE_MASK << LW_HASH_STATE_SHIFT;
thin |= (u4)mon | LW_SHAPE_FAT;
/* Publish the updated lock word. */
android_atomic_release_store(thin, (int32_t *)&obj->lock);
}
void
DOMStorageDBThread::ThreadFunc()
{
nsresult rv = InitDatabase();
MonitorAutoLock lockMonitor(mThreadObserver->GetMonitor());
if (NS_FAILED(rv)) {
mStatus = rv;
mStopIOThread = true;
return;
}
// Create an nsIThread for the current PRThread, so we can observe runnables
// dispatched to it.
nsCOMPtr<nsIThread> thread = NS_GetCurrentThread();
nsCOMPtr<nsIThreadInternal> threadInternal = do_QueryInterface(thread);
MOZ_ASSERT(threadInternal); // Should always succeed.
threadInternal->SetObserver(mThreadObserver);
while (MOZ_LIKELY(!mStopIOThread || mPreloads.Length() ||
mPendingTasks.HasTasks() ||
mThreadObserver->HasPendingEvents())) {
// Process xpcom events first.
while (MOZ_UNLIKELY(mThreadObserver->HasPendingEvents())) {
mThreadObserver->ClearPendingEvents();
MonitorAutoUnlock unlock(mThreadObserver->GetMonitor());
bool processedEvent;
do {
rv = thread->ProcessNextEvent(false, &processedEvent);
} while (NS_SUCCEEDED(rv) && processedEvent);
}
if (MOZ_UNLIKELY(TimeUntilFlush() == 0)) {
// Flush time is up or flush has been forced, do it now.
UnscheduleFlush();
if (mPendingTasks.Prepare()) {
{
MonitorAutoUnlock unlockMonitor(mThreadObserver->GetMonitor());
rv = mPendingTasks.Execute(this);
}
if (!mPendingTasks.Finalize(rv)) {
mStatus = rv;
NS_WARNING("localStorage DB access broken");
}
}
NotifyFlushCompletion();
} else if (MOZ_LIKELY(mPreloads.Length())) {
nsAutoPtr<DBOperation> op(mPreloads[0]);
mPreloads.RemoveElementAt(0);
{
MonitorAutoUnlock unlockMonitor(mThreadObserver->GetMonitor());
op->PerformAndFinalize(this);
}
if (op->Type() == DBOperation::opPreloadUrgent) {
SetDefaultPriority(); // urgent preload unscheduled
}
} else if (MOZ_UNLIKELY(!mStopIOThread)) {
lockMonitor.Wait(TimeUntilFlush());
}
} // thread loop
mStatus = ShutdownDatabase();
if (threadInternal) {
threadInternal->SetObserver(nullptr);
}
}
/**
* The unsigned indexbyte1 and indexbyte2 are used to construct an index into the runtime constant pool of the current class (§2.6),
* where the value of the index is (indexbyte1 << 8) | indexbyte2. The runtime constant pool item at that index must be a symbolic reference to a method (§5.1),
* which gives the name and descriptor (§4.3.3) of the method as well as a symbolic reference to the class in which the method is to be found.
* The named method is resolved (§5.4.3.3). Finally, if the resolved method is protected (§4.6), and it is a member of a superclass of the current class,
* and the method is not declared in the same runtime package (§5.3) as the current class,
* then the class of objectref must be either the current class or a subclass of the current class.
*/
void JavaVM::pushNewFrame(StackFrame * stackFrame)
{
Frame * frame = stackFrame->top();
//get a process counter and get a next instruction
//invoke instance method on object objectref, where the method is identified by method reference index in constant pool (indexbyte1 << 8 + indexbyte2)
u1 * ptr = &frame->_code->code[frame->_pc + 1];
u2 method_index = getu2(ptr);
CPBase * pConstPool = frame->_clazz->_constantPool[method_index];
//get method
ASSERT(pConstPool->tag == CONSTANT_Methodref);
CONSTANT_Methodref_info_resolve * method_ref = reinterpret_cast<CONSTANT_Methodref_info_resolve *>(pConstPool);
/*get class name*/
std::string class_name;
class_name.assign((const char *)method_ref->_class_index->_name_index->bytes, method_ref->_class_index->_name_index->length);
boost::shared_ptr<JavaClass> clazz(_classHeap->getClass(class_name));
/*get method*/
std::string method_name, method_desc;
frame->_clazz->getStringFromConstPool(method_ref->_name_and_type_index->name_index, method_name);
frame->_clazz->getStringFromConstPool(method_ref->_name_and_type_index->descriptor_index, method_desc);
printf("invoke %s.%s:%s\n", class_name.c_str(), method_name.c_str(), method_desc.c_str());
jClass virtual_clazz(clazz);
u2 nIndex = clazz->getMethodID(method_name, method_desc, virtual_clazz);
Frame * new_f = new Frame();
new_f->_clazz = virtual_clazz;
new_f->_method = virtual_clazz->_methods[nIndex];
if (!(virtual_clazz->_methods[nIndex]->getAccessFlags() & ACC_NATIVE)) // there is no code
{
Code_attribute * code = virtual_clazz->getMethodCodeAttribute(nIndex);
new_f->setCode(code);
}
else
{
Code_attribute * code = new Code_attribute();
code->max_locals = 1;
code->max_stack = 0;
code->code = NULL;
new_f->setCode(code);
}
/*
* The Java virtual machine uses local variables to pass parameters on method invocation
* http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-2.html#jvms-2.6.1
*/
std::string params = countMethodStack(method_desc);
for (std::size_t i = params.length(), j = i; i >= 0; i--, j--)
{
/**
* The objectref and the argument values are consecutively made the values of local variables of the new frame,
* with objectref in local variable 0,
* arg1 in local variable 1 (or, if arg1 is of type long or double, in local variables 1 and 2), and so on
*/
new_f->_localVariable[i] = frame->_operandStack.top();
frame->_operandStack.pop();
//TODO melhorar
if (i == 0)
break;
/* if it is long or double I need to add 1 in local variable */
if(params.size() > 0 && (params[j-1] =='J' || params[j-1] =='D'))
i--;
}
if (new_f->_method->getAccessFlags() & ACC_SYNCHRONIZED)
{
if (lockMonitor(new_f->_localVariable[0]._var._objectref))
{
}
else
{
new_f->_lock = true;
new_f->_waitingObj = new_f->_localVariable[0]._var._objectref;
this->wait(new_f->_waitingObj, boost::bind(&Frame::unlock, new_f));
}
}
//if this method has ACC_SYNCHRONIZED then I need to do monitorenter, it is implicit
//I need to get new_f->_localVariable[0], this location in array is objref, I need to lock this object
stackFrame->push(new_f);
}
/*
* Implements monitorenter for "synchronized" stuff.
*
* This does not fail or throw an exception (unless deadlock prediction
* is enabled and set to "err" mode).
*/
void dvmLockObject(Thread* self, Object *obj)
{
volatile u4 *thinp;
ThreadStatus oldStatus;
struct timespec tm;
long sleepDelayNs;
long minSleepDelayNs = 1000000; /* 1 millisecond */
long maxSleepDelayNs = 1000000000; /* 1 second */
u4 thin, newThin, threadId;
assert(self != NULL);
assert(obj != NULL);
threadId = self->threadId;
thinp = &obj->lock;
retry:
thin = *thinp;
if (LW_SHAPE(thin) == LW_SHAPE_THIN) {
/*
* The lock is a thin lock. The owner field is used to
* determine the acquire method, ordered by cost.
*/
if (LW_LOCK_OWNER(thin) == threadId) {
/*
* The calling thread owns the lock. Increment the
* value of the recursion count field.
*/
obj->lock += 1 << LW_LOCK_COUNT_SHIFT;
if (LW_LOCK_COUNT(obj->lock) == LW_LOCK_COUNT_MASK) {
/*
* The reacquisition limit has been reached. Inflate
* the lock so the next acquire will not overflow the
* recursion count field.
*/
inflateMonitor(self, obj);
}
} else if (LW_LOCK_OWNER(thin) == 0) {
/*
* The lock is unowned. Install the thread id of the
* calling thread into the owner field. This is the
* common case. In performance critical code the JIT
* will have tried this before calling out to the VM.
*/
newThin = thin | (threadId << LW_LOCK_OWNER_SHIFT);
if (android_atomic_acquire_cas(thin, newThin,
(int32_t*)thinp) != 0) {
/*
* The acquire failed. Try again.
*/
goto retry;
}
} else {
ALOGV("(%d) spin on lock %p: %#x (%#x) %#x",
threadId, &obj->lock, 0, *thinp, thin);
/*
* The lock is owned by another thread. Notify the VM
* that we are about to wait.
*/
oldStatus = dvmChangeStatus(self, THREAD_MONITOR);
/*
* Spin until the thin lock is released or inflated.
*/
sleepDelayNs = 0;
for (;;) {
thin = *thinp;
/*
* Check the shape of the lock word. Another thread
* may have inflated the lock while we were waiting.
*/
if (LW_SHAPE(thin) == LW_SHAPE_THIN) {
if (LW_LOCK_OWNER(thin) == 0) {
/*
* The lock has been released. Install the
* thread id of the calling thread into the
* owner field.
*/
newThin = thin | (threadId << LW_LOCK_OWNER_SHIFT);
if (android_atomic_acquire_cas(thin, newThin,
(int32_t *)thinp) == 0) {
/*
* The acquire succeed. Break out of the
* loop and proceed to inflate the lock.
*/
break;
}
} else {
/*
* The lock has not been released. Yield so
* the owning thread can run.
*/
if (sleepDelayNs == 0) {
sched_yield();
sleepDelayNs = minSleepDelayNs;
} else {
tm.tv_sec = 0;
tm.tv_nsec = sleepDelayNs;
nanosleep(&tm, NULL);
/*
* Prepare the next delay value. Wrap to
* avoid once a second polls for eternity.
*/
if (sleepDelayNs < maxSleepDelayNs / 2) {
sleepDelayNs *= 2;
} else {
sleepDelayNs = minSleepDelayNs;
}
}
}
} else {
/*
* The thin lock was inflated by another thread.
* Let the VM know we are no longer waiting and
* try again.
*/
ALOGV("(%d) lock %p surprise-fattened",
threadId, &obj->lock);
dvmChangeStatus(self, oldStatus);
goto retry;
}
}
ALOGV("(%d) spin on lock done %p: %#x (%#x) %#x",
threadId, &obj->lock, 0, *thinp, thin);
/*
* We have acquired the thin lock. Let the VM know that
* we are no longer waiting.
*/
dvmChangeStatus(self, oldStatus);
/*
* Fatten the lock.
*/
inflateMonitor(self, obj);
ALOGV("(%d) lock %p fattened", threadId, &obj->lock);
}
} else {
/*
* The lock is a fat lock.
*/
assert(LW_MONITOR(obj->lock) != NULL);
lockMonitor(self, LW_MONITOR(obj->lock));
}
}
/*
* Wait on a monitor until timeout, interrupt, or notification. Used for
* Object.wait() and (somewhat indirectly) Thread.sleep() and Thread.join().
*
* If another thread calls Thread.interrupt(), we throw InterruptedException
* and return immediately if one of the following are true:
* - blocked in wait(), wait(long), or wait(long, int) methods of Object
* - blocked in join(), join(long), or join(long, int) methods of Thread
* - blocked in sleep(long), or sleep(long, int) methods of Thread
* Otherwise, we set the "interrupted" flag.
*
* Checks to make sure that "nsec" is in the range 0-999999
* (i.e. fractions of a millisecond) and throws the appropriate
* exception if it isn't.
*
* The spec allows "spurious wakeups", and recommends that all code using
* Object.wait() do so in a loop. This appears to derive from concerns
* about pthread_cond_wait() on multiprocessor systems. Some commentary
* on the web casts doubt on whether these can/should occur.
*
* Since we're allowed to wake up "early", we clamp extremely long durations
* to return at the end of the 32-bit time epoch.
*/
static void waitMonitor(Thread* self, Monitor* mon, s8 msec, s4 nsec,
bool interruptShouldThrow)
{
struct timespec ts;
bool wasInterrupted = false;
bool timed;
int ret;
assert(self != NULL);
assert(mon != NULL);
/* Make sure that we hold the lock. */
if (mon->owner != self) {
dvmThrowIllegalMonitorStateException(
"object not locked by thread before wait()");
return;
}
/*
* Enforce the timeout range.
*/
if (msec < 0 || nsec < 0 || nsec > 999999) {
dvmThrowIllegalArgumentException("timeout arguments out of range");
return;
}
/*
* Compute absolute wakeup time, if necessary.
*/
if (msec == 0 && nsec == 0) {
timed = false;
} else {
absoluteTime(msec, nsec, &ts);
timed = true;
}
/*
* Add ourselves to the set of threads waiting on this monitor, and
* release our hold. We need to let it go even if we're a few levels
* deep in a recursive lock, and we need to restore that later.
*
* We append to the wait set ahead of clearing the count and owner
* fields so the subroutine can check that the calling thread owns
* the monitor. Aside from that, the order of member updates is
* not order sensitive as we hold the pthread mutex.
*/
waitSetAppend(mon, self);
int prevLockCount = mon->lockCount;
mon->lockCount = 0;
mon->owner = NULL;
const Method* savedMethod = mon->ownerMethod;
u4 savedPc = mon->ownerPc;
mon->ownerMethod = NULL;
mon->ownerPc = 0;
/*
* Update thread status. If the GC wakes up, it'll ignore us, knowing
* that we won't touch any references in this state, and we'll check
* our suspend mode before we transition out.
*/
if (timed)
dvmChangeStatus(self, THREAD_TIMED_WAIT);
else
dvmChangeStatus(self, THREAD_WAIT);
dvmLockMutex(&self->waitMutex);
/*
* Set waitMonitor to the monitor object we will be waiting on.
* When waitMonitor is non-NULL a notifying or interrupting thread
* must signal the thread's waitCond to wake it up.
*/
assert(self->waitMonitor == NULL);
self->waitMonitor = mon;
/*
* Handle the case where the thread was interrupted before we called
* wait().
*/
if (self->interrupted) {
wasInterrupted = true;
self->waitMonitor = NULL;
dvmUnlockMutex(&self->waitMutex);
goto done;
}
/*
* Release the monitor lock and wait for a notification or
* a timeout to occur.
*/
dvmUnlockMutex(&mon->lock);
if (!timed) {
ret = pthread_cond_wait(&self->waitCond, &self->waitMutex);
assert(ret == 0);
} else {
#ifdef HAVE_TIMEDWAIT_MONOTONIC
ret = pthread_cond_timedwait_monotonic(&self->waitCond, &self->waitMutex, &ts);
#else
ret = pthread_cond_timedwait(&self->waitCond, &self->waitMutex, &ts);
#endif
assert(ret == 0 || ret == ETIMEDOUT);
}
if (self->interrupted) {
wasInterrupted = true;
}
self->interrupted = false;
self->waitMonitor = NULL;
dvmUnlockMutex(&self->waitMutex);
/* Reacquire the monitor lock. */
lockMonitor(self, mon);
done:
/*
* We remove our thread from wait set after restoring the count
* and owner fields so the subroutine can check that the calling
* thread owns the monitor. Aside from that, the order of member
* updates is not order sensitive as we hold the pthread mutex.
*/
mon->owner = self;
mon->lockCount = prevLockCount;
mon->ownerMethod = savedMethod;
mon->ownerPc = savedPc;
waitSetRemove(mon, self);
/* set self->status back to THREAD_RUNNING, and self-suspend if needed */
dvmChangeStatus(self, THREAD_RUNNING);
if (wasInterrupted) {
/*
* We were interrupted while waiting, or somebody interrupted an
* un-interruptible thread earlier and we're bailing out immediately.
*
* The doc sayeth: "The interrupted status of the current thread is
* cleared when this exception is thrown."
*/
self->interrupted = false;
if (interruptShouldThrow) {
dvmThrowInterruptedException(NULL);
}
}
}
