[lldb/swig] Fix ref counting issue in SBProcess::GetScriptedImplementation

[mib]

Summary

When using SBProcess::GetScriptedImplementation in python, if the
process has a valid implementation, we returned a reference of the
object without incrementing the reference counting. That causes the
interpreter to crash after accessing the reference several times.

This patch address this by incrementing the reference count when passing
the valid object reference.

Signed-off-by: Med Ismail Bennani <[e-mail]>

[JDevlieghere]

LGTM. Can we turn that crash into a small test case?

[mib]

Add test

lldb/bindings/python/python-typemaps.swig

 
 %typemap(out) lldb::ScriptedObject {
   $result = nullptr;
   if (const void* impl = $1)
     $result = (PyObject*) impl;
   if (!$result) {
     $result = Py_None;
     Py_INCREF(Py_None);
+  } else {
+    Py_INCREF($result);
   }
 }
 
 %typemap(out) char** {
   int len;
   int i;
   len = 0;
   while ($1[len])

lldb/test/API/functionalities/scripted_process/TestScriptedProcess.py

def test_invalid_scripted_register_context(self):
 
         process = target.Launch(launch_info, error)
 
         self.assertSuccess(error)
         self.assertTrue(process, PROCESS_IS_VALID)
         self.assertEqual(process.GetProcessID(), 666)
         self.assertEqual(process.GetNumThreads(), 0)
 
+        impl = process.GetScriptedImplementation()
+        self.assertTrue(impl)
+        impl = process.GetScriptedImplementation()
+        self.assertTrue(impl)
+        impl = process.GetScriptedImplementation()
+        self.assertTrue(impl)
+        impl = process.GetScriptedImplementation()
+        self.assertTrue(impl)
+
         addr = 0x500000000
         buff = process.ReadMemory(addr, 4, error)
         self.assertEqual(buff, None)
         self.assertTrue(error.Fail())
         self.assertEqual(error.GetCString(), "This is an invalid scripted process!")
 
         with open(log_file, 'r') as f:
             log = f.read()