Revert "Switch profiler from isolates to threads"

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index 997be09b3749453806a888a3e29f765b8b911383..b9626d57fde3f06a096d471a90fc2a3c7ac8eab6 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -784,6 +784,7 @@ Isolate::Isolate(const Dart_IsolateFlags& api_flags)
       last_allocationprofile_gc_timestamp_(0),
       object_id_ring_(NULL),
       trace_buffer_(NULL),
+      profiler_data_(NULL),
       tag_table_(GrowableObjectArray::null()),
       deoptimized_code_array_(GrowableObjectArray::null()),
       background_compiler_(NULL),
@@ -1715,6 +1716,7 @@ void Isolate::Shutdown() {
   Thread::ExitIsolate();
   // All threads should have exited by now.
   thread_registry()->CheckNotScheduled(this);
+  Profiler::ShutdownProfilingForIsolate(this);
 }
 
 
@@ -1919,6 +1921,62 @@ void Isolate::PrintJSON(JSONStream* stream, bool ref) {
 }
 
 
+intptr_t Isolate::ProfileInterrupt() {
+  // Other threads might be modifying these fields. Save them in locals so that
+  // we can at least trust the NULL check.
+  IsolateProfilerData* prof_data = profiler_data();
+  if (prof_data == NULL) {
+    // Profiler not setup for isolate.
+    return 0;
+  }
+  if (prof_data->blocked()) {
+    // Profiler blocked for this isolate.
+    return 0;
+  }
+  Debugger* debug = debugger();
+  if ((debug != NULL) && debug->IsPaused()) {
+    // Paused at breakpoint. Don't tick.
+    return 0;
+  }
+  MessageHandler* msg_handler = message_handler();
+  if ((msg_handler != NULL) &&
+      (msg_handler->paused_on_start() ||
+       msg_handler->paused_on_exit())) {
+    // Paused at start / exit . Don't tick.
+    return 0;
+  }
+  // Make sure that the isolate's mutator thread does not change behind our
+  // backs. Otherwise we find the entry in the registry and end up reading
+  // the field again. Only by that time it has been reset to NULL because the
+  // thread was in process of exiting the isolate.
+  Thread* mutator = mutator_thread_;
+  if (mutator == NULL) {
+    // No active mutator.
+    ProfileIdle();
+    return 1;
+  }
+
+  // TODO(johnmccutchan): Sample all threads, not just the mutator thread.
+  // TODO(johnmccutchan): Keep a global list of threads and use that
+  // instead of Isolate.
+  ThreadRegistry::EntryIterator it(thread_registry());
+  while (it.HasNext()) {
+    const ThreadRegistry::Entry& entry = it.Next();
+    if (entry.thread == mutator) {
+      ThreadInterrupter::InterruptThread(mutator);
+      break;
+    }
+  }
+  return 1;
+}
+
+
+void Isolate::ProfileIdle() {
+  // Currently we are only sampling the mutator thread.
+  vm_tag_counters_.Increment(VMTag::kIdleTagId);
+}
+
+
 void Isolate::set_tag_table(const GrowableObjectArray& value) {
   tag_table_ = value.raw();
 }