gui: Updated singleton pattern for gui::Gui::get().

The stub verson of gui::Gui::get() no longer returns nullptr.

Signed-off-by: Ted Hong <[email protected]>

Author: hongted

src/gui/include/gui/gui.h

@@ -947,8 +947,6 @@ class Gui
   std::unique_ptr<GIF> gif_;
   static constexpr int kDefaultGifDelay = 250;
 
-  static Gui* singleton_;
-
   std::string main_window_title_ = "OpenROAD";
 };
 

src/gui/src/gui.cpp

@@ -208,14 +208,9 @@ static void resetConversions()
       = [](const std::string& value, bool*) { return 0; };
 }
 
-Gui* Gui::singleton_ = nullptr;
-
 Gui* Gui::get()
 {
-  if (singleton_ == nullptr) {
-    singleton_ = new Gui();
-  }
-
+  static Gui* singleton_ = new Gui();
   return singleton_;
 }
 

src/gui/src/stub.cpp

@@ -24,8 +24,6 @@ struct GifWriter
 
 namespace gui {
 
-Gui* Gui::singleton_ = nullptr;
-
 // Used by toString to convert dbu to microns
 DBUToString Descriptor::Property::convert_dbu
     = [](int value, bool) { return std::to_string(value); };
@@ -54,6 +52,7 @@ Gui::Gui() : continue_after_close_(false), logger_(nullptr), db_(nullptr)
 
 Gui* gui::Gui::get()
 {
+  static Gui* singleton_ = new Gui();
   return singleton_;
 }