Switch profiler from isolates to threads

runtime/vm/thread.cc

Index: runtime/vm/thread.cc
diff --git a/runtime/vm/thread.cc b/runtime/vm/thread.cc
index a2af102a7ebc4736a645e2fd800e2c5b4ef5aa8a..c4bfd365c5351a6608cf78fc34500efcf6a2fd83 100644
--- a/runtime/vm/thread.cc
+++ b/runtime/vm/thread.cc
@@ -66,6 +66,9 @@ void Thread::AddThreadToList(Thread* thread) {
   // Insert at head of list.
   thread->thread_list_next_ = thread_list_head_;
   thread_list_head_ = thread;
+
+  // Make sure the thread interrupter is awake.
+  ThreadInterrupter::WakeUp();
 }
 
 
@@ -180,6 +183,7 @@ Thread::Thread(bool init_vm_constants)
     : id_(OSThread::GetCurrentThreadId()),
       thread_interrupt_callback_(NULL),
       thread_interrupt_data_(NULL),
+      thread_interrupt_disabled_(0),
       isolate_(NULL),
       heap_(NULL),
       timeline_block_(NULL),
@@ -452,6 +456,29 @@ void Thread::VisitObjectPointers(ObjectPointerVisitor* visitor) {
 }
 
 
+void Thread::DisableThreadInterrupts() {
+  ASSERT(Thread::Current() == this);
+  AtomicOperations::FetchAndIncrement(&thread_interrupt_disabled_);
+}
+
+
+void Thread::EnableThreadInterrupts() {
+  ASSERT(Thread::Current() == this);
+  uintptr_t old =
+      AtomicOperations::FetchAndDecrement(&thread_interrupt_disabled_);
+  if (old == 1) {
+    // We just decremented from 1 to 0.
+    // Make sure the thread interrupter is awake.
+    ThreadInterrupter::WakeUp();
+  }
+}
+
+
+bool Thread::ThreadInterruptsEnabled() {
+  return AtomicOperations::LoadRelaxed(&thread_interrupt_disabled_) == 0;
+}
+
+
 void Thread::SetThreadInterrupter(ThreadInterruptCallback callback,
                                   void* data) {
   ASSERT(Thread::Current() == this);