diff --git a/lldb/include/lldb/Target/OperatingSystem.h b/lldb/include/lldb/Target/OperatingSystem.h
index ceeddceb0f2c1..d02bd3fb01738 100644
--- a/lldb/include/lldb/Target/OperatingSystem.h
+++ b/lldb/include/lldb/Target/OperatingSystem.h
@@ -14,6 +14,7 @@
 #include "lldb/lldb-private.h"
 
 namespace lldb_private {
+class ThreadPlanStackMap;
 
 /// \class OperatingSystem OperatingSystem.h "lldb/Target/OperatingSystem.h"
 /// A plug-in interface definition class for halted OS helpers.
@@ -45,7 +46,8 @@ class OperatingSystem : public PluginInterface {
   // Plug-in Methods
   virtual bool UpdateThreadList(ThreadList &old_thread_list,
                                 ThreadList &real_thread_list,
-                                ThreadList &new_thread_list) = 0;
+                                ThreadList &new_thread_list,
+                                ThreadPlanStackMap &plan_stack_map) = 0;
 
   virtual void ThreadWasSelected(Thread *thread) = 0;
 
diff --git a/lldb/include/lldb/Target/ThreadPlanStack.h b/lldb/include/lldb/Target/ThreadPlanStack.h
index e0f8104de9a4d..da4dac5595d62 100644
--- a/lldb/include/lldb/Target/ThreadPlanStack.h
+++ b/lldb/include/lldb/Target/ThreadPlanStack.h
@@ -179,6 +179,13 @@ class ThreadPlanStackMap {
                        
   bool PrunePlansForTID(lldb::tid_t tid);
 
+  std::vector<lldb::tid_t> GetKnownTIDs() const {
+    std::vector<lldb::tid_t> TIDs;
+    for (auto &plan_stack : m_plans_up_container)
+      TIDs.push_back(plan_stack->GetTID());
+    return TIDs;
+  }
+
 private:
   Process &m_process;
   mutable std::recursive_mutex m_stack_map_mutex;
diff --git a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp
index 3848a2b1deb97..85ff005f7eac8 100644
--- a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp
+++ b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp
@@ -163,7 +163,8 @@ DynamicRegisterInfo *OperatingSystemPython::GetDynamicRegisterInfo() {
 
 bool OperatingSystemPython::UpdateThreadList(ThreadList &old_thread_list,
                                              ThreadList &core_thread_list,
-                                             ThreadList &new_thread_list) {
+                                             ThreadList &new_thread_list,
+                                             ThreadPlanStackMap &) {
   if (!m_interpreter || !m_operating_system_interface_sp)
     return false;
 
diff --git a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h
index 90973acde3ebf..e9782ae8b2c59 100644
--- a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h
+++ b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h
@@ -44,9 +44,11 @@ class OperatingSystemPython : public lldb_private::OperatingSystem {
   llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
 
   // lldb_private::OperatingSystem Methods
-  bool UpdateThreadList(lldb_private::ThreadList &old_thread_list,
-                        lldb_private::ThreadList &real_thread_list,
-                        lldb_private::ThreadList &new_thread_list) override;
+  bool
+  UpdateThreadList(lldb_private::ThreadList &old_thread_list,
+                   lldb_private::ThreadList &real_thread_list,
+                   lldb_private::ThreadList &new_thread_list,
+                   lldb_private::ThreadPlanStackMap &plan_stack_map) override;
 
   void ThreadWasSelected(lldb_private::Thread *thread) override;
 
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index 68485a40a3fcc..6b2c1c2fdf24c 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -1202,8 +1202,9 @@ void Process::UpdateThreadListIfNeeded() {
               real_thread_list, // The actual thread list full of threads
                                 // created by each lldb_private::Process
                                 // subclass
-              new_thread_list); // The new thread list that we will show to the
+              new_thread_list,  // The new thread list that we will show to the
                                 // user that gets filled in
+              m_thread_plans);
 
           if (saved_prefer_dynamic != lldb::eNoDynamicValues)
             target.SetPreferDynamicValue(saved_prefer_dynamic);