[lldb] Add missing return statements in ThreadMemory

These prevented ThreadMemory from correctly returning the
Name/Queue/Info of the backing thread.

Note about testing: this test only finds regressions if the system sets
a name or queue for the backing thread. While this may not be true
everywhere, it still provides coverage in some systems, e.g. in Apple
platforms.

Author: felipepiovezan

lldb/source/Plugins/Process/Utility/ThreadMemory.h

@@ -33,23 +33,23 @@ class ThreadMemory : public lldb_private::Thread {
 
   const char *GetInfo() override {
     if (m_backing_thread_sp)
-      m_backing_thread_sp->GetInfo();
+      return m_backing_thread_sp->GetInfo();
     return nullptr;
   }
 
   const char *GetName() override {
     if (!m_name.empty())
       return m_name.c_str();
     if (m_backing_thread_sp)
-      m_backing_thread_sp->GetName();
+      return m_backing_thread_sp->GetName();
     return nullptr;
   }
 
   const char *GetQueueName() override {
     if (!m_queue.empty())
       return m_queue.c_str();
     if (m_backing_thread_sp)
-      m_backing_thread_sp->GetQueueName();
+      return m_backing_thread_sp->GetQueueName();
     return nullptr;
   }
 

lldb/test/API/functionalities/plugins/python_os_plugin/TestPythonOSPlugin.py

@@ -160,6 +160,8 @@ def run_python_os_step(self):
         )
         self.assertTrue(process, PROCESS_IS_VALID)
 
+        core_thread_zero = process.GetThreadAtIndex(0)
+
         # Make sure there are no OS plug-in created thread when we first stop
         # at our breakpoint in main
         thread = process.GetThreadByID(0x111111111)
@@ -183,6 +185,10 @@ def run_python_os_step(self):
             thread.IsValid(),
             "Make sure there is a thread 0x111111111 after we load the python OS plug-in",
         )
+        # This OS plugin does not set thread names / queue names, so it should
+        # inherit the core thread's name.
+        self.assertEqual(core_thread_zero.GetName(), thread.GetName())
+        self.assertEqual(core_thread_zero.GetQueueName(), thread.GetQueueName())
 
         frame = thread.GetFrameAtIndex(0)
         self.assertTrue(