Index: lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h
===================================================================
--- lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h
+++ lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h
@@ -9,6 +9,7 @@
 #ifndef liblldb_Lua_h_
 #define liblldb_Lua_h_
 
+#include "lldb/lldb-types.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Error.h"
 
@@ -35,11 +36,15 @@
     luaL_openlibs(m_lua_state);
   }
 
+  llvm::Error EnterSession(lldb::user_id_t debugger_id);
+  llvm::Error LeaveSession();
+
   llvm::Error Run(llvm::StringRef buffer);
 
 private:
   std::mutex m_mutex;
   lua_State *m_lua_state;
+  bool m_session_is_active = false;
 };
 
 } // namespace lldb_private
Index: lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp
===================================================================
--- lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp
+++ lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp
@@ -10,6 +10,7 @@
 #include "llvm/Support/FormatVariadic.h"
 
 using namespace lldb_private;
+using namespace lldb;
 
 llvm::Error Lua::Run(llvm::StringRef buffer) {
   std::lock_guard<std::mutex> lock(m_mutex);
@@ -26,3 +27,27 @@
   lua_pop(m_lua_state, 1);
   return e;
 }
+
+llvm::Error Lua::EnterSession(user_id_t debugger_id) {
+  if (m_session_is_active)
+    return llvm::Error::success();
+
+  m_session_is_active = true;
+  std::string buffer = llvm::formatv(
+      "lldb.debugger = lldb.SBDebugger.FindDebuggerWithID({0})", debugger_id);
+  buffer.append("; lldb.target = lldb.debugger:GetSelectedTarget()");
+  buffer.append("; lldb.process = lldb.target:GetProcess()");
+  buffer.append("; lldb.thread = lldb.process:GetSelectedThread()");
+  buffer.append("; lldb.frame = lldb.thread:GetSelectedFrame ()");
+  return Run(buffer);
+}
+
+llvm::Error Lua::LeaveSession() {
+  m_session_is_active = false;
+  std::string buffer = "lldb.debugger = nil";
+  buffer.append("; lldb.target = nil");
+  buffer.append("; lldb.process = nil");
+  buffer.append("; lldb.thread = nil");
+  buffer.append("; lldb.frame = nil");
+  return Run(buffer);
+}
Index: lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp
===================================================================
--- lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp
+++ lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp
@@ -27,7 +27,14 @@
       : IOHandlerEditline(debugger, IOHandler::Type::LuaInterpreter, "lua",
                           ">>> ", "..> ", true, debugger.GetUseColor(), 0,
                           *this, nullptr),
-        m_script_interpreter(script_interpreter) {}
+        m_script_interpreter(script_interpreter) {
+    llvm::cantFail(
+        m_script_interpreter.GetLua().EnterSession(debugger.GetID()));
+  }
+
+  ~IOHandlerLuaInterpreter() {
+    llvm::cantFail(m_script_interpreter.GetLua().LeaveSession());
+  }
 
   void IOHandlerInputComplete(IOHandler &io_handler,
                               std::string &data) override {
Index: lldb/test/Shell/ScriptInterpreter/Lua/convenience_variables.test
===================================================================
--- /dev/null
+++ lldb/test/Shell/ScriptInterpreter/Lua/convenience_variables.test
@@ -0,0 +1,17 @@
+# REQUIRES: lua
+#
+# This tests that the convenience variables are not nil. Given that there is no
+# target we only expect the debugger to be valid.
+#
+# RUN: cat %s | %lldb --script-language lua 2>&1 | FileCheck %s
+script
+print(string.format("lldb.debugger is valid: %s", lldb.debugger:IsValid()))
+print(string.format("lldb.target is valid: %s", lldb.target:IsValid()))
+print(string.format("lldb.process is valid: %s", lldb.process:IsValid()))
+print(string.format("lldb.thread is valid: %s", lldb.thread:IsValid()))
+print(string.format("lldb.frame is valid: %s", lldb.frame:IsValid()))
+# CHECK: debugger is valid: true
+# CHECK: target is valid: false
+# CHECK: process is valid: false
+# CHECK: thread is valid: false
+# CHECK: frame is valid: false