Index: include/lldb/Interpreter/PythonDataObjects.h
===================================================================
--- include/lldb/Interpreter/PythonDataObjects.h
+++ include/lldb/Interpreter/PythonDataObjects.h
@@ -51,6 +51,14 @@
             Reset (NULL);
         }
 
+        PyObject*
+        Release()
+        {
+            PyObject* obj = m_py_obj;
+            m_py_obj = nullptr;
+            return obj;
+        }
+
         bool
         Reset (const PythonObject &object)
         {
Index: source/Interpreter/ScriptInterpreterPython.cpp
===================================================================
--- source/Interpreter/ScriptInterpreterPython.cpp
+++ source/Interpreter/ScriptInterpreterPython.cpp
@@ -209,6 +209,11 @@
 
 ScriptInterpreterPython::~ScriptInterpreterPython ()
 {
+    // Release the underlying PyObjects.  Python will have already decref'ed these to 0 during
+    // Py_Finalize(), so allowing them to be destructed normally will cause Python to assert with a
+    // debug build.
+    m_session_dict.Release();
+    m_sys_module_dict.Release();
 }
 
 void
@@ -1806,7 +1811,11 @@
     Locker locker(this,
                   ScriptInterpreterPython::Locker::AcquireLock,
                   ScriptInterpreterPython::Locker::FreeAcquiredLock);
-    PyRun_SimpleString("lldb.debugger = None; lldb.target = None; lldb.process = None; lldb.thread = None; lldb.frame = None");
+
+    // This may be called as part of Py_Finalize.  In that case the modules are destroyed in random
+    // order and we can't guarantee that we can access these.
+    if (Py_IsInitialized())
+        PyRun_SimpleString("lldb.debugger = None; lldb.target = None; lldb.process = None; lldb.thread = None; lldb.frame = None");
 }
 
 bool
Index: test/dotest.py
===================================================================
--- test/dotest.py
+++ test/dotest.py
@@ -20,7 +20,6 @@
 for available options.
 """
 
-import atexit
 import commands
 import os
 import errno
@@ -419,7 +418,6 @@
         cmd = "xcrun clang %s -o %s -framework Python -Xlinker -dylib -iframework /System/Library/Frameworks/ -Xlinker -F /System/Library/Frameworks/" % (dylib_src,dylib_dst)
         if subprocess.call(cmd,shell=True) == 0 and os.path.exists(dylib_dst):
             setCrashInfoHook = setCrashInfoHook_Mac
-            atexit.register(deleteCrashInfoDylib,dylib_dst)
     else:
         pass
 
@@ -1232,11 +1230,7 @@
 
 # For the time being, let's bracket the test runner within the
 # lldb.SBDebugger.Initialize()/Terminate() pair.
-import lldb, atexit
-# Update: the act of importing lldb now executes lldb.SBDebugger.Initialize(),
-# there's no need to call it a second time.
-#lldb.SBDebugger.Initialize()
-atexit.register(lambda: lldb.SBDebugger.Terminate())
+import lldb
 
 # Create a singleton SBDebugger in the lldb namespace.
 lldb.DBG = lldb.SBDebugger.Create()
@@ -1246,6 +1240,7 @@
     lldb.remote_platform = lldb.SBPlatform(lldb_platform_name)
     if not lldb.remote_platform.IsValid():
         print "error: unable to create the LLDB platform named '%s'." % (lldb_platform_name)
+        lldb.SBDebugger.Terminate()
         sys.exit(1)
     if lldb_platform_url:
         # We must connect to a remote platform if a LLDB platform URL was specified
@@ -1256,6 +1251,7 @@
             print "Connected."
         else:
             print "error: failed to connect to remote platform using URL '%s': %s" % (lldb_platform_url, err)
+            lldb.SBDebugger.Terminate()
             sys.exit(1)
     
     if lldb_platform_working_dir:
@@ -1397,6 +1393,7 @@
 
 if not compilers or len(compilers) == 0:
     print "No eligible compiler found, exiting."
+    lldb.SBDebugger.Terminate()
     sys.exit(1)
 
 if isinstance(compilers, list) and len(compilers) >= 1:
@@ -1738,4 +1735,4 @@
     subprocess.Popen(["/bin/sh", "-c", "kill %s; exit 0" % (os.getpid())])
 
 # Exiting.
-sys.exit(failed)
+lldb.SBDebugger.Terminate()