Support wedging isolates before startup or before exit.

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index a2f10ac7b3dc258b8eb58b17bd6cfea3573db904..0d32f427c9c4afa461c864866d4d65d7e05facc0 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -41,8 +41,10 @@ DEFINE_FLAG(bool, report_usage_count, false,
             "Track function usage and report.");
 DEFINE_FLAG(bool, trace_isolates, false,
             "Trace isolate creation and shut down.");
-DEFINE_FLAG(bool, pin_isolates, false,
-            "Stop isolates from being destroyed automatically.");
+DEFINE_FLAG(bool, pause_isolates_on_start, false,
+            "Pause isolates before starting.");
+DEFINE_FLAG(bool, pause_isolates_on_exit, false,
+            "Pause isolates exiting.");
 
 
 void Isolate::RegisterClass(const Class& cls) {
@@ -299,7 +301,6 @@ Isolate::Isolate()
       message_notify_callback_(NULL),
       name_(NULL),
       start_time_(OS::GetCurrentTimeMicros()),
-      pin_port_(0),
       main_port_(0),
       heap_(NULL),
       object_store_(NULL),
@@ -436,9 +437,8 @@ Isolate* Isolate::Init(const char* name_prefix) {
   result->SetStackLimitFromCurrentTOS(reinterpret_cast<uword>(&result));
   result->set_main_port(PortMap::CreatePort(result->message_handler()));
   result->BuildName(name_prefix);
-  if (FLAG_pin_isolates) {
-    result->CreatePinPort();
-  }
+  result->message_handler()->set_pause_on_start(FLAG_pause_isolates_on_start);
+  result->message_handler()->set_pause_on_exit(FLAG_pause_isolates_on_exit);
 
   result->debugger_ = new Debugger();
   result->debugger_->Initialize(result);
@@ -454,28 +454,6 @@ Isolate* Isolate::Init(const char* name_prefix) {
 }
 
 
-void Isolate::CreatePinPort() {
-  ASSERT(FLAG_pin_isolates);
-  // Only do this once.
-  ASSERT(pin_port_ == 0);
-  pin_port_ = PortMap::CreatePort(message_handler());
-  ASSERT(pin_port_ != 0);
-  PortMap::SetLive(pin_port_);
-}
-
-
-void Isolate::ClosePinPort() {
-  if (pin_port_ == 0) {
-    // Support multiple calls to close.
-    return;
-  }
-  ASSERT(pin_port_ != 0);
-  bool r = PortMap::ClosePort(pin_port_);
-  ASSERT(r);
-  pin_port_ = 0;
-}
-
-
 void Isolate::BuildName(const char* name_prefix) {
   ASSERT(name_ == NULL);
   if (name_prefix == NULL) {
@@ -916,7 +894,16 @@ void Isolate::PrintToJSONStream(JSONStream* stream) {
     // inlined frames.
     jsobj.AddProperty("depth", (intptr_t)0);
   }
-
+  intptr_t live_ports = message_handler()->live_ports();
+  intptr_t control_ports = message_handler()->control_ports();
+  bool paused_on_exit = message_handler()->paused_on_exit();
+  bool pause_on_start = message_handler()->pause_on_start();
+  bool pause_on_exit = message_handler()->pause_on_exit();
+  jsobj.AddProperty("live_ports", live_ports);
+  jsobj.AddProperty("control_ports", control_ports);
+  jsobj.AddProperty("paused_on_exit", paused_on_exit);
+  jsobj.AddProperty("paused_on_start", pause_on_start);
+  jsobj.AddProperty("pause_on_exit", pause_on_exit);
   const Library& lib =
       Library::Handle(object_store()->root_library());
   jsobj.AddProperty("rootLib", lib);