1377490 - Make nsWindow final to allow the compiler to devirtualize some calls

Status: RESOLVED FIXED

(Core :: Widget: Win32, enhancement)

Description

[Mats Palmgren (inactive)]

My first attempt didn't quite work out:
https://hg.mozilla.org/try/rev/635d506cdeb8aff7f21d8a7c93dfc23c889b2d02
It seems like it should be an idempotent change, but apparently not:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=ed958cccbc7f110e2fbb49c79f2b09d7b8d4b20d

I'll try adding a bool:1 on nsWindow to indicate the special
"ChidlWindow" behavior for WindowStyle() instead...

Comment 1

[Mats Palmgren (inactive)]

Attachment: Make nsWindow 'final' to possibly devirtualize some calls

This should be an idempotent change.  I think we could get rid of
the mIsChildWindow flag if the 'mWindowType' values used for
nsWindow vs ChildWindow are disjoint, but I'll leave that for
a follow-up bug (if you think it's possible).

There were a few M(c3) failures, but after a few more runs it
looks like they were just noise.
https://treeherder.mozilla.org/#/jobs?repo=try&revision=bc1d738fd463c618db9d542a9676e70a329a45be

Comment 2

[Xidorn Quan [:xidorn] UTC+10]

Comment on attachment 8882718 [details] [diff] [review]
Make nsWindow 'final' to possibly devirtualize some calls

Review of attachment 8882718 [details] [diff] [review]:
-----------------------------------------------------------------

::: widget/windows/nsWindow.h
@@ +77,5 @@
>    typedef mozilla::widget::MSGResult MSGResult;
>    typedef mozilla::widget::IMEContext IMEContext;
>  
>  public:
> +  nsWindow(bool aIsChildWindow = false);

You should probably add "explicit" here. I don't think we want a bool to be able to implicitly convertible to a nsWindow.

We should have been checking this on Linux and probably also macOS builds, but that check may not be available with MSVC.

Comment 3

[Mats Palmgren (inactive)]

(In reply to Xidorn Quan [:xidorn] UTC+10 from comment #2)
> You should probably add "explicit" here. I don't think we want a bool to be
> able to implicitly convertible to a nsWindow.

Heh, yeah, I forgot.  Thanks, I'll add it.

> We should have been checking this on Linux and probably also macOS builds,
> but that check may not be available with MSVC.

I'm doing similar changes for gtk in bug 1377486 and cocoa in bug 1377591.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/8b0cc21a82b3
Make nsWindow 'final' to possibly devirtualize some calls.  r=jimm

Comment 5

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/8b0cc21a82b3