867420 - AsyncPanZoomController.h & CompositorParent.cpp triggers build warning: deleting object of polymorphic class type 'mozilla::layers::AsyncCompositionManager' which has non-virtual destructor might cause undefined behaviour [-Wdelete-non-virtual-dtor]

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Daniel Holbert [:dholbert] (AFK Aug 23-25)]

New GCC build warning (I'm using GCC 4.8):
{
In file included from /mozilla-central/gfx/layers/ipc/AsyncPanZoomController.h:13:0,
                 from /mozilla-central/gfx/layers/ipc/CompositorParent.cpp:11:
../../dist/include/mozilla/RefPtr.h: In instantiation of 'void mozilla::RefCounted<T>::Release() [with T = mozilla::layers::AsyncCompositionManager]':
../../dist/include/mozilla/RefPtr.h:171:9:   required from 'static void mozilla::RefPtr<T>::unref(T*) [with T = mozilla::layers::AsyncCompositionManager]'
../../dist/include/mozilla/RefPtr.h:121:26:   required from 'mozilla::RefPtr<T>::~RefPtr() [with T = mozilla::layers::AsyncCompositionManager]'
/mozilla-central/gfx/layers/ipc/CompositorParent.cpp:139:34:   required from here
../../dist/include/mozilla/RefPtr.h:76:9: warning: deleting object of polymorphic class type 'mozilla::layers::AsyncCompositionManager' which has non-virtual destructor might cause undefined behaviour [-Wdelete-non-virtual-dtor]
         delete static_cast<T*>(this);
         ^
}

This can be fixed by a MOZ_FINAL annotation (which tells the compiler we don't have to worry about there being any subclasses, so we don't need a virtual destructor).  I'll push
that with blanket-r=ehsan, per bug 829975 comment 3.

Comment 1

[Daniel Holbert [:dholbert] (AFK Aug 23-25)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/3d939baa396b

Comment 2

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/3d939baa396b