[lldb/Lua] Add Boilerplate for a Lua Script Interpreter

This adds the boilerplate necessary to support the Lua script
interpreter. The interpreter is not functional yet and just reports that
it's not implemented.

Discussion on the mailing list:
http://lists.llvm.org/pipermail/lldb-dev/2019-December/015812.html

Differential revision: https://reviews.llvm.org/D71232

4 files changed, 129 insertions, 0 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/CMakeLists.txt b/lldb/source/Plugins/ScriptInterpreter/CMakeLists.txt
index 416f6800513..fa1c72a32fe 100644
--- a/lldb/source/Plugins/ScriptInterpreter/CMakeLists.txt
+++ b/lldb/source/Plugins/ScriptInterpreter/CMakeLists.txt
@@ -2,3 +2,7 @@ add_subdirectory(None)
 if (LLDB_ENABLE_PYTHON)
   add_subdirectory(Python)
 endif()
+
+if (LLDB_ENABLE_LUA)
+  add_subdirectory(Lua)
+endif()
diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/CMakeLists.txt b/lldb/source/Plugins/ScriptInterpreter/Lua/CMakeLists.txt
new file mode 100644
index 00000000000..51161638a3d
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Lua/CMakeLists.txt
@@ -0,0 +1,7 @@
+add_lldb_library(lldbPluginScriptInterpreterLua PLUGIN
+  ScriptInterpreterLua.cpp
+
+  LINK_LIBS
+    lldbCore
+    lldbInterpreter
+  )
\ No newline at end of file
diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp
new file mode 100644
index 00000000000..78aa91a6959
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp
@@ -0,0 +1,71 @@
+//===-- ScriptInterpreterLua.cpp --------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "ScriptInterpreterLua.h"
+#include "lldb/Core/Debugger.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/StreamFile.h"
+#include "lldb/Utility/Stream.h"
+#include "lldb/Utility/StringList.h"
+
+#include "llvm/Support/Threading.h"
+
+#include <mutex>
+
+using namespace lldb;
+using namespace lldb_private;
+
+ScriptInterpreterLua::ScriptInterpreterLua(Debugger &debugger)
+    : ScriptInterpreter(debugger, eScriptLanguageLua) {}
+
+ScriptInterpreterLua::~ScriptInterpreterLua() {}
+
+bool ScriptInterpreterLua::ExecuteOneLine(llvm::StringRef command,
+                                          CommandReturnObject *,
+                                          const ExecuteScriptOptions &) {
+  m_debugger.GetErrorStream().PutCString(
+      "error: the lua script interpreter is not yet implemented.\n");
+  return false;
+}
+
+void ScriptInterpreterLua::ExecuteInterpreterLoop() {
+  m_debugger.GetErrorStream().PutCString(
+      "error: the lua script interpreter is not yet implemented.\n");
+}
+
+void ScriptInterpreterLua::Initialize() {
+  static llvm::once_flag g_once_flag;
+
+  llvm::call_once(g_once_flag, []() {
+    PluginManager::RegisterPlugin(GetPluginNameStatic(),
+                                  GetPluginDescriptionStatic(),
+                                  lldb::eScriptLanguageLua, CreateInstance);
+  });
+}
+
+void ScriptInterpreterLua::Terminate() {}
+
+lldb::ScriptInterpreterSP
+ScriptInterpreterLua::CreateInstance(Debugger &debugger) {
+  return std::make_shared<ScriptInterpreterLua>(debugger);
+}
+
+lldb_private::ConstString ScriptInterpreterLua::GetPluginNameStatic() {
+  static ConstString g_name("script-lua");
+  return g_name;
+}
+
+const char *ScriptInterpreterLua::GetPluginDescriptionStatic() {
+  return "Lua script interpreter";
+}
+
+lldb_private::ConstString ScriptInterpreterLua::GetPluginName() {
+  return GetPluginNameStatic();
+}
+
+uint32_t ScriptInterpreterLua::GetPluginVersion() { return 1; }
diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h
new file mode 100644
index 00000000000..7f69a73f588
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h
@@ -0,0 +1,47 @@
+//===-- ScriptInterpreterLua.h ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_ScriptInterpreterLua_h_
+#define liblldb_ScriptInterpreterLua_h_
+
+#include "lldb/Interpreter/ScriptInterpreter.h"
+
+namespace lldb_private {
+
+class ScriptInterpreterLua : public ScriptInterpreter {
+public:
+  ScriptInterpreterLua(Debugger &debugger);
+
+  ~ScriptInterpreterLua() override;
+
+  bool ExecuteOneLine(
+      llvm::StringRef command, CommandReturnObject *result,
+      const ExecuteScriptOptions &options = ExecuteScriptOptions()) override;
+
+  void ExecuteInterpreterLoop() override;
+
+  // Static Functions
+  static void Initialize();
+
+  static void Terminate();
+
+  static lldb::ScriptInterpreterSP CreateInstance(Debugger &debugger);
+
+  static lldb_private::ConstString GetPluginNameStatic();
+
+  static const char *GetPluginDescriptionStatic();
+
+  // PluginInterface protocol
+  lldb_private::ConstString GetPluginName() override;
+
+  uint32_t GetPluginVersion() override;
+};
+
+} // namespace lldb_private
+
+#endif // liblldb_ScriptInterpreterLua_h_