Bug 1331792 - Stop using MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE in functions called from destructors to better work around VC++ compiler warnings. r=gfx?

MozReview-Commit-ID: Jh0OooS3ijl

gfx/webrender_bindings/RendererOGL.cpp

@@ -39,13 +39,7 @@ RendererOGL::RendererOGL(RefPtr<RenderThread>&& aThread,
 RendererOGL::~RendererOGL()
 {
   MOZ_COUNT_DTOR(RendererOGL);
-#ifdef MOZ_ENABLE_WEBRENDER
-  // Need to wrap this in an ifdef otherwise VC++ emits a warning (treated as error)
-  // in the non-webrender targets.
-  // We should be able to remove this #ifdef if/when we remove the
-  // MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE annotations in webrender.h
   wr_renderer_delete(mWrRenderer);
-#endif
 }
 
 void

gfx/webrender_bindings/WebRenderAPI.cpp

@@ -154,13 +154,7 @@ WebRenderAPI::~WebRenderAPI()
   RunOnRenderThread(Move(event));
   task.Wait();
 
-#ifdef MOZ_ENABLE_WEBRENDER
-  // Need to wrap this in an ifdef otherwise VC++ emits a warning (treated as error)
-  // in the non-webrender targets.
-  // We should be able to remove this #ifdef if/when we remove the
-  // MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE annotations in webrender.h
   wr_api_delete(mWrApi);
-#endif
 }
 
 void
@@ -262,12 +256,8 @@ WebRenderAPI::SetProfilerEnabled(bool aEnabled)
 void
 WebRenderAPI::RunOnRenderThread(UniquePtr<RendererEvent>&& aEvent)
 {
-#ifdef MOZ_ENABLE_WEBRENDER
-  // ifdef this out so that calling this function from a destructor does
-  // not break windows builds...
   auto event = reinterpret_cast<uintptr_t>(aEvent.release());
   wr_api_send_external_event(mWrApi, event);
-#endif
 }
 
 DisplayListBuilder::DisplayListBuilder(const LayerIntSize& aSize, PipelineId aId)
@@ -279,9 +269,7 @@ DisplayListBuilder::DisplayListBuilder(const LayerIntSize& aSize, PipelineId aId
 DisplayListBuilder::~DisplayListBuilder()
 {
   MOZ_COUNT_DTOR(DisplayListBuilder);
-#ifdef MOZ_ENABLE_WEBRENDER
   wr_state_delete(mWrState);
-#endif
 }
 
 void

gfx/webrender_bindings/webrender_ffi.h

@@ -266,12 +266,21 @@ struct WrExternalImageIdHandler
 // Functions exposed by the webrender API
 // -----
 
+// Some useful defines to stub out webrender binding functions for when we
+// build gecko without webrender. We try to tell the compiler these functions
+// are unreachable in that case, but VC++ emits a warning if it finds any
+// unreachable functions invoked from destructors. That warning gets turned into
+// an error and causes the build to fail. So for wr_* functions called by
+// destructors in C++ classes, use WR_DESTRUCTOR_SAFE_FUNC instead, which omits
+// the unreachable annotation.
 #ifdef MOZ_ENABLE_WEBRENDER
 #  define WR_INLINE
 #  define WR_FUNC
+#  define WR_DESTRUCTOR_SAFE_FUNC
 #else
 #  define WR_INLINE inline
 #  define WR_FUNC { MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("WebRender disabled"); }
+#  define WR_DESTRUCTOR_SAFE_FUNC {}
 #endif
 
 // Structs defined in Rust, but opaque to C++ code.
@@ -299,7 +308,7 @@ WR_FUNC;
 
 WR_INLINE void
 wr_renderer_delete(WrRenderer* renderer)
-WR_FUNC;
+WR_DESTRUCTOR_SAFE_FUNC;
 
 WR_INLINE void
 wr_gl_init(void* aGLContext)
@@ -316,7 +325,7 @@ WR_FUNC;
 
 WR_INLINE void
 wr_api_delete(WrAPI* api)
-WR_FUNC;
+WR_DESTRUCTOR_SAFE_FUNC;
 
 WR_INLINE WrImageKey
 wr_api_add_image(WrAPI* api, uint32_t width, uint32_t height,
@@ -348,7 +357,7 @@ WR_FUNC;
 
 WR_INLINE void
 wr_api_send_external_event(WrAPI* api, uintptr_t evt)
-WR_FUNC;
+WR_DESTRUCTOR_SAFE_FUNC;
 
 WR_INLINE void
 wr_window_init_pipeline_epoch(WrWindowState* window, WrPipelineId pipeline, uint32_t width, uint32_t height)
@@ -375,7 +384,7 @@ WR_FUNC;
 
 WR_INLINE void
 wr_state_delete(WrState* state)
-WR_FUNC;
+WR_DESTRUCTOR_SAFE_FUNC;
 
 WR_INLINE void
 wr_destroy(WrWindowState* wrWindow, WrState* WrState)
@@ -485,6 +494,7 @@ wr_profiler_set_enabled(WrWindowState* wrWindow, bool enabled)
 WR_FUNC;
 
 #undef WR_FUNC
+#undef WR_DESTRUCTOR_SAFE_FUNC
 } // extern "C"
 
 #endif // WR_h