[lldb][NFCI] Change type of SBDebugger::m_instance_name

This doesn't need to be in the ConstString StringPool. There's little
benefit to having these be unique, and we don't need fast comparisons on
them.

Differential Revision: https://reviews.llvm.org/D151524

lldb/include/lldb/Core/Debugger.h

@@ -116,7 +116,7 @@ class Debugger : public std::enable_shared_from_this<Debugger>,
   static lldb::DebuggerSP FindDebuggerWithID(lldb::user_id_t id);
 
   static lldb::DebuggerSP
-  FindDebuggerWithInstanceName(ConstString instance_name);
+  FindDebuggerWithInstanceName(llvm::StringRef instance_name);
 
   static size_t GetNumDebuggers();
 
@@ -359,7 +359,7 @@ class Debugger : public std::enable_shared_from_this<Debugger>,
 
   bool GetNotifyVoid() const;
 
-  ConstString GetInstanceName() { return m_instance_name; }
+  const std::string &GetInstanceName() { return m_instance_name; }
 
   bool LoadPlugin(const FileSpec &spec, Status &error);
 
@@ -644,7 +644,7 @@ class Debugger : public std::enable_shared_from_this<Debugger>,
 
   llvm::StringMap<std::weak_ptr<LogHandler>> m_stream_handlers;
   std::shared_ptr<CallbackLogHandler> m_callback_handler_sp;
-  ConstString m_instance_name;
+  const std::string m_instance_name;
   static LoadPluginCallbackType g_load_plugin_callback;
   typedef std::vector<llvm::sys::DynamicLibrary> LoadedPluginsList;
   LoadedPluginsList m_loaded_plugins;

lldb/source/API/SBDebugger.cpp

@@ -1326,16 +1326,19 @@ SBDebugger SBDebugger::FindDebuggerWithID(int id) {
 const char *SBDebugger::GetInstanceName() {
   LLDB_INSTRUMENT_VA(this);
 
-  return (m_opaque_sp ? m_opaque_sp->GetInstanceName().AsCString() : nullptr);
+  if (!m_opaque_sp)
+    return nullptr;
+
+  return ConstString(m_opaque_sp->GetInstanceName()).AsCString();
 }
 
 SBError SBDebugger::SetInternalVariable(const char *var_name, const char *value,
                                         const char *debugger_instance_name) {
   LLDB_INSTRUMENT_VA(var_name, value, debugger_instance_name);
 
   SBError sb_error;
-  DebuggerSP debugger_sp(Debugger::FindDebuggerWithInstanceName(
-      ConstString(debugger_instance_name)));
+  DebuggerSP debugger_sp(
+      Debugger::FindDebuggerWithInstanceName(debugger_instance_name));
   Status error;
   if (debugger_sp) {
     ExecutionContext exe_ctx(
@@ -1356,8 +1359,8 @@ SBDebugger::GetInternalVariableValue(const char *var_name,
                                      const char *debugger_instance_name) {
   LLDB_INSTRUMENT_VA(var_name, debugger_instance_name);
 
-  DebuggerSP debugger_sp(Debugger::FindDebuggerWithInstanceName(
-      ConstString(debugger_instance_name)));
+  DebuggerSP debugger_sp(
+      Debugger::FindDebuggerWithInstanceName(debugger_instance_name));
   Status error;
   if (debugger_sp) {
     ExecutionContext exe_ctx(
@@ -1487,7 +1490,7 @@ bool SBDebugger::GetDescription(SBStream &description) {
   Stream &strm = description.ref();
 
   if (m_opaque_sp) {
-    const char *name = m_opaque_sp->GetInstanceName().AsCString();
+    const char *name = m_opaque_sp->GetInstanceName().c_str();
     user_id_t id = m_opaque_sp->GetID();
     strm.Printf("Debugger (instance: \"%s\", id: %" PRIu64 ")", name, id);
   } else

lldb/source/Core/Debugger.cpp

@@ -740,19 +740,20 @@ void Debugger::Destroy(DebuggerSP &debugger_sp) {
   }
 }
 
-DebuggerSP Debugger::FindDebuggerWithInstanceName(ConstString instance_name) {
-  DebuggerSP debugger_sp;
-  if (g_debugger_list_ptr && g_debugger_list_mutex_ptr) {
-    std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
-    DebuggerList::iterator pos, end = g_debugger_list_ptr->end();
-    for (pos = g_debugger_list_ptr->begin(); pos != end; ++pos) {
-      if ((*pos)->m_instance_name == instance_name) {
-        debugger_sp = *pos;
-        break;
-      }
-    }
+DebuggerSP
+Debugger::FindDebuggerWithInstanceName(llvm::StringRef instance_name) {
+  if (!g_debugger_list_ptr || !g_debugger_list_mutex_ptr)
+    return DebuggerSP();
+
+  std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
+  for (const DebuggerSP &debugger_sp : *g_debugger_list_ptr) {
+    if (!debugger_sp)
+      continue;
+
+    if (llvm::StringRef(debugger_sp->GetInstanceName()) == instance_name)
+      return debugger_sp;
   }
-  return debugger_sp;
+  return DebuggerSP();
 }
 
 TargetSP Debugger::FindTargetWithProcessID(lldb::pid_t pid) {
@@ -801,13 +802,13 @@ Debugger::Debugger(lldb::LogOutputCallback log_callback, void *baton)
       m_source_manager_up(), m_source_file_cache(),
       m_command_interpreter_up(
           std::make_unique<CommandInterpreter>(*this, false)),
-      m_io_handler_stack(), m_instance_name(), m_loaded_plugins(),
-      m_event_handler_thread(), m_io_handler_thread(),
+      m_io_handler_stack(),
+      m_instance_name(llvm::formatv("debugger_{0}", GetID()).str()),
+      m_loaded_plugins(), m_event_handler_thread(), m_io_handler_thread(),
       m_sync_broadcaster(nullptr, "lldb.debugger.sync"),
       m_broadcaster(m_broadcaster_manager_sp,
                     GetStaticBroadcasterClass().AsCString()),
       m_forward_listener_sp(), m_clear_once() {
-  m_instance_name.SetString(llvm::formatv("debugger_{0}", GetID()).str());
   // Initialize the debugger properties as early as possible as other parts of
   // LLDB will start querying them during construction.
   m_collection_sp->Initialize(g_debugger_properties);

lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp

@@ -408,7 +408,7 @@ ScriptInterpreterPythonImpl::ScriptInterpreterPythonImpl(Debugger &debugger)
       m_session_dict(PyInitialValue::Invalid),
       m_sys_module_dict(PyInitialValue::Invalid), m_run_one_line_function(),
       m_run_one_line_str_global(),
-      m_dictionary_name(m_debugger.GetInstanceName().AsCString()),
+      m_dictionary_name(m_debugger.GetInstanceName()),
       m_active_io_handler(eIOHandlerNone), m_session_is_active(false),
       m_pty_secondary_is_open(false), m_valid_session(true), m_lock_count(0),
       m_command_thread_state(nullptr) {