Only suggest final when using non-LTO builds

In LTO builds GCC issues the suggestion-warning from linking stage,
when pragmas are already gone and do nothing.

CMakeLists.txt

@@ -122,16 +122,6 @@ if (ENABLE_LIGHTFX)
     add_definitions(-D__ENABLE_LIGHTFX__)
 endif ()
 
-if (CXX_WARN_SUGGEST_FINAL_TYPES)
-    # Disable -Wsuggest-final-types via pragmas where due.
-   add_definitions(-D__WARN_SUGGEST_FINAL_TYPES__)
-endif ()
-
-if (CXX_WARN_SUGGEST_FINAL_METHODS)
-    # Disable -Wsuggest-final-methods via pragmas where due.
-   add_definitions(-D__WARN_SUGGEST_FINAL_METHODS__)
-endif ()
-
 if (NOT DISABLE_DISCORD_RPC)
     if(EXISTS "${ROOT_DIR}/discord-rpc")
         # Don't build discord's examples, some of which are in C and do not honour
@@ -202,8 +192,6 @@ if (MSVC)
     add_definitions(-DNOMINMAX)
 else ()
     ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_NULL_DEREFERENCE -Wnull-dereference)
-    ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_TYPES -Wsuggest-final-types)
-    ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_METHODS -Wsuggest-final-methods)
     ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_OVERRIDE -Wsuggest-override)
     ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_DUPLICATED_COND -Wduplicated-cond)
     ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_NON_VIRTUAL_DTOR -Wnon-virtual-dtor)
@@ -224,6 +212,11 @@ else ()
         # Do not enable for MinGW, as its headers contain redundant declarations of builtin functions
         ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_REDUNDANT_DECLS -Wredundant-decls)
     endif ()
+    # These have no workarounds available when building with LTO
+    if (NOT IPO_BUILD_ENABLED)
+        ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_TYPES -Wsuggest-final-types)
+        ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_METHODS -Wsuggest-final-methods)
+    endif ()
     ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_IGNORED_QUALIFIERS -Wignored-qualifiers)
 
     # -Wstrict-overflow is only active when -fstrict-overflow is enabled, but -fstrict-overflow
@@ -254,6 +247,16 @@ else ()
     endif ()
 endif ()
 
+if (CXX_WARN_SUGGEST_FINAL_TYPES)
+    # Disable -Wsuggest-final-types via pragmas where due.
+   add_definitions(-D__WARN_SUGGEST_FINAL_TYPES__)
+endif ()
+
+if (CXX_WARN_SUGGEST_FINAL_METHODS)
+    # Disable -Wsuggest-final-methods via pragmas where due.
+   add_definitions(-D__WARN_SUGGEST_FINAL_METHODS__)
+endif ()
+
 # Include sub-projects
 include("${ROOT_DIR}/src/openrct2/CMakeLists.txt" NO_POLICY_SCOPE)
 include("${ROOT_DIR}/src/openrct2-cli/CMakeLists.txt" NO_POLICY_SCOPE)

src/openrct2-ui/audio/AudioContext.cpp

@@ -18,7 +18,7 @@
 
 namespace OpenRCT2::Audio
 {
-    class AudioContext : public IAudioContext
+    class AudioContext final : public IAudioContext
     {
     private:
         IAudioMixer* _audioMixer = nullptr;

src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp

@@ -172,7 +172,7 @@ public:
     }
 };
 
-class OpenGLDrawingEngine : public IDrawingEngine
+class OpenGLDrawingEngine final : public IDrawingEngine
 {
 private:
     std::shared_ptr<IUiContext> const _uiContext;

src/openrct2/Context.cpp

@@ -79,7 +79,7 @@ using namespace OpenRCT2::Ui;
 
 namespace OpenRCT2
 {
-    class Context : public IContext
+    class Context final : public IContext
     {
     private:
         // Dependencies

src/openrct2/GameStateSnapshots.cpp

@@ -109,7 +109,7 @@ struct GameStateSnapshot_t
     }
 };
 
-struct GameStateSnapshots : public IGameStateSnapshots
+struct GameStateSnapshots final : public IGameStateSnapshots
 {
     virtual void Reset() override final
     {

src/openrct2/actions/GameAction.h

@@ -297,7 +297,7 @@ namespace GameActions
             return #cls;                                                         \
         }                                                                        \
     };                                                                           \
-    struct cls : public GameActionBase<id, res>
+    struct cls final : public GameActionBase<id, res>
     // clang-format on
 
 } // namespace GameActions

src/openrct2/actions/TrackPlaceAction.hpp

@@ -74,7 +74,7 @@ public:
         _origin.direction &= 3;
     }
 
-    uint16_t GetActionFlags() const override
+    uint16_t GetActionFlags() const override final
     {
         return GameAction::GetActionFlags();
     }

src/openrct2/core/IStream.hpp

@@ -24,6 +24,12 @@ enum
     STREAM_SEEK_END
 };
 
+#ifdef __WARN_SUGGEST_FINAL_METHODS__
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wsuggest-final-methods"
+#    pragma GCC diagnostic ignored "-Wsuggest-final-types"
+#endif
+
 /**
  * Represents a stream that can be read or written to. Implemented by types such as FileStream, NetworkStream or MemoryStream.
  */
@@ -199,6 +205,10 @@ interface IStream
     void WriteString(const std::string& string);
 };
 
+#ifdef __WARN_SUGGEST_FINAL_METHODS__
+#    pragma GCC diagnostic pop
+#endif
+
 class IOException : public std::runtime_error
 {
 public:

src/openrct2/drawing/X8DrawingEngine.h

@@ -85,7 +85,16 @@ namespace OpenRCT2
 
         public:
             explicit X8DrawingEngine(const std::shared_ptr<Ui::IUiContext>& uiContext);
+
+#ifdef __WARN_SUGGEST_FINAL_METHODS__
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wsuggest-final-methods"
+#    pragma GCC diagnostic ignored "-Wsuggest-final-types"
+#endif
             ~X8DrawingEngine() override;
+#ifdef __WARN_SUGGEST_FINAL_METHODS__
+#    pragma GCC diagnostic pop
+#endif
 
             void Initialise() override;
             void Resize(uint32_t width, uint32_t height) override;