874736 - 98 lines of GCC build warnings from -Woverloaded-virtual in gfx/layers/composite, due to two CompositableHost::EnsureTextureHost methods

Status: RESOLVED DUPLICATE of bug 876661

(Core :: Graphics: Layers, defect)

Description

[Daniel Holbert [:dholbert]]

I get nearly 100 lines of GCC buildwarning spam in gfx/layers/composite, from -Woverloaded-virtual.

The warnings look like:
{
In file included from /scratch/work/builds/mozilla-inbound/mozilla/gfx/layers/composite/CompositableHost.cpp:6:0:
/scratch/work/builds/mozilla-inbound/mozilla/gfx/layers/composite/CompositableHost.h:153:16: warning: ‘virtual void mozilla::layers::CompositableHost::EnsureTextureHost(mozilla::layers::ISurfaceAllocator*, const mozilla::layers::TextureInfo&, const nsIntRect&)’ was hidden [-Woverloaded-virtual]
In file included from /scratch/work/builds/mozilla-inbound/mozilla/gfx/layers/composite/CompositableHost.cpp:7:0:
/scratch/work/builds/mozilla-inbound/mozilla/gfx/layers/composite/ImageHost.h:51:16: warning:   by ‘virtual void mozilla::layers::ImageHostSingle::EnsureTextureHost(mozilla::layers::TextureIdentifier, const mozilla::layers::SurfaceDescriptor&, mozilla::layers::ISurfaceAllocator*, const mozilla::layers::TextureInfo&)’ [-Woverloaded-virtual]
}

http://stackoverflow.com/questions/9995421/gcc-woverloaded-virtual-warnings has an explanation for what's going on here.

IIRC you can suppress these warnings by adding a "using CompositableHost::EnsureTextureHost;" declaration to the affected classes.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: warnings

Attaching a log of all these warnings.

Comment 2

[Daniel Holbert [:dholbert]]

Looks like this was introduced a week ago by http://hg.mozilla.org/mozilla-central/rev/a1bb5799f8ee which added the second EnsureTextureHost declaration.

I'm using GCC 4.8, BTW (though I think this affects all GCC versions; not sure about other compilers).

Comment 3

[Arnaud Sourioux [:Six]]

Attachment: Annotate "using CompositableHost::EnsureTextureHost;" to fix warnings with -Woverloaded-virtual in gfx/layers/composite

Looks ok on my linux64

Comment 4

[Nicolas Silva [:nical]]

Comment on attachment 759171 [details] [diff] [review]
Annotate "using CompositableHost::EnsureTextureHost;" to fix warnings with -Woverloaded-virtual in gfx/layers/composite

Review of attachment 759171 [details] [diff] [review]:
-----------------------------------------------------------------

Looks like a good short term solution although it can probably be a bit confusing since it's a rather unusual pattern. The work I am doing on textures gets rid of EnsureTextureHost so this confusion about overloaded virtual methods will not stay in the code for too long (hopefully).

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/ac18c74b3a2c

Comment 6

[Arnaud Sourioux [:Six]]

daniel could you try the patch to confirm it is gone away on your machine?

Comment 7

[Daniel Holbert [:dholbert]]

I actually don't get the build warning in up-to-date mozilla-central now (without this bug's patch -- I verified that my clone doesn't have the cset from comment 5).

So something else apparently fixed this (without the "using" declaration) -- looks like it was bug 876661 (which was really a dupe of this bug).  The patch there took a different approach -- renaming one of the methods.

I'm forward-duping this to that bug, and we should back out comment 5, since we don't need the "using" declaration now.

Comment 8

[Daniel Holbert [:dholbert]]

Backed out: https://hg.mozilla.org/integration/mozilla-inbound/rev/0ae723d89b73

Thanks anyway for taking this, Arnaud, and sorry for the confusion!

Comment 9

[Arnaud Sourioux [:Six]]

OK if it's fixed it's okay for me even if it's not my patch that is being used :)