[interp] Send CreateThread debugger event from the interpreter

src/coreclr/debug/ee/debugger.cpp

@@ -8886,6 +8886,40 @@ void Debugger::ThreadStarted(Thread* pRuntimeThread)
 }
 
 
+void Debugger::SendCreateThreadAtInterpreterEntry(Thread *pRuntimeThread)
+{
+    CONTRACTL
+    {
+        NOTHROW;
+        GC_TRIGGERS;
+        MODE_ANY;
+        PRECONDITION(pRuntimeThread != NULL);
+        PRECONDITION(pRuntimeThread == g_pEEInterface->GetThread());
+    }
+    CONTRACTL_END;
+
+    if (CORDBUnrecoverableError(this))
+        return;
+
+    if (!CORDebuggerAttached())
+        return;
+
+    {
+        GCX_PREEMP();
+        PollWaitingForHelper();
+    }
+
+    SENDIPCEVENT_BEGIN(this, pRuntimeThread);
+
+    if (CORDebuggerAttached())
+    {
+        ThreadStarted(pRuntimeThread);
+    }
+
+    SENDIPCEVENT_END;
+}
+
+
 //---------------------------------------------------------------------------------------
 //
 // DetachThread is called by Runtime threads when they are completing

src/coreclr/debug/ee/debugger.h

@@ -1925,6 +1925,7 @@ class Debugger : public DebugInterface
 
     void ThreadCreated(Thread* pRuntimeThread);
     void ThreadStarted(Thread* pRuntimeThread);
+    void SendCreateThreadAtInterpreterEntry(Thread* pRuntimeThread);
     void DetachThread(Thread *pRuntimeThread);
 
     BOOL SuspendComplete(bool isEESuspendedForGC = false);

src/coreclr/vm/dbginterface.h

@@ -380,6 +380,8 @@ class DebugInterface
     virtual void ExternalMethodFixupNextStep(PCODE address) = 0;
     virtual void ProcessAnyPendingEvals(Thread* pThread) = 0;
 
+    virtual void SendCreateThreadAtInterpreterEntry(Thread* pRuntimeThread) = 0;
+
 #endif //DACCESS_COMPILE
 };
 

src/coreclr/vm/threads.cpp

@@ -6558,14 +6558,21 @@ InterpThreadContext* Thread::GetOrCreateInterpThreadContext()
     CONTRACTL
     {
         THROWS;
-        GC_NOTRIGGER;
+        GC_TRIGGERS;
         MODE_ANY;
     }
     CONTRACTL_END;
 
     if (m_pInterpThreadContext == nullptr)
     {
         m_pInterpThreadContext = new InterpThreadContext();
+
+#ifdef DEBUGGING_SUPPORTED
+        if (CORDebuggerAttached() && g_pDebugInterface != NULL)
+        {
+            g_pDebugInterface->SendCreateThreadAtInterpreterEntry(this);
+        }
+#endif // DEBUGGING_SUPPORTED
     }
 
     return m_pInterpThreadContext;