1564873 - Use MaybeUninit instead of mem::uninitialized in WebRender

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, enhancement)

Description

[Simon Sapin (:SimonSapin)]

Part of bug 1563623.

Comment 1

[Simon Sapin (:SimonSapin)]

Attachment: Bug 1564873 - Use MaybeUninit instead of mem::uninitialized in WebRender

MozReview-Commit-ID: 67kmn5v43eW

Comment 2

[Simon Sapin (:SimonSapin)]

Attachment: Bug 1564873 - Require !Drop when unsafely pushing uninitialized items to a generic Vec

MozReview-Commit-ID: 9ZW2dQiO60z

Comment 4

[Josh Matthews [:jdm]]

There are no reviewers specified on these patches. Is that intentional?

Comment 5

[Simon Sapin (:SimonSapin)]

Added gfx as a reviewer. I think it represents anyone in that group?

Comment 6

[Kartikaya Gupta (email:[e-mail])]

(In reply to Simon Sapin (:SimonSapin) from comment #5)

Added gfx as a reviewer. I think it represents anyone in that group?

I chnaged the reviewer to Gankro. The gfx reviewer is left over from the early WR workflows but isn't really used now. I'll remove that phabricator account if I can.

Comment 7

[Jeff Muizelaar [:jrmuizel]]

Alexis, do you mind taking a look at this again? 1.39 turns this into a warning which broke our CI. As a workaround we'll probably switch to 1.38 but we should probably do something sooner rather than later.

Comment 8

[Aria Beingessner [:Gankra]]

Do you want me to do it or is Simon planning a rebase?

Comment 9

[Jeff Muizelaar [:jrmuizel]]

I have no preference. I'll let you two fight it out.

Comment 10

[Simon Sapin (:SimonSapin)]

Alexis, could you take over? I started this hoping apply similar patterns of changes in all of Gecko, but that Vec of GPU data probably deserves more attention than that and I don’t really understand what makes it sound or how it could be made sound.

Comment 11

[Simon Sapin (:SimonSapin)]

This should also revert https://phabricator.services.mozilla.com/D52360

Comment 12

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1564873 - Fix straight-forward uses of mem::uninitialized in webrender. r=SimonSapin,Gankro

Comment 13

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1564873 - Stop using mem::uninitialized to pass memory to the GPU. r=SimonSapin,Gankro

Use Vec::reserve + as_ptr, then raw pointers.

Alternative is to require T: Default, and then push T::default() or something.

Depends on D53359

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/582c1acfb348
Stop using mem::uninitialized to pass memory to the GPU. r=Gankro

Comment 15

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/582c1acfb348

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/82e4062e839a
Fix straight-forward uses of mem::uninitialized in webrender. r=nical

Comment 17

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/82e4062e839a