Bug 208659 – Remove the optimization for discarding no operation DisplayList items between Save and Restore items

• Status: RESOLVED
• Resolution: FIXED
• Component: Canvas

[Said Abou-Hallawa]

The restoreIndex was an opportunity of optimization. If all no drawing between the Save and Restore happens, this means these items are all void and can be deleted from the DisplayList. With the canvas drawing and with batching the DisplayList flushing, this causes a serious problem when we try to remove the items at and after currentState().saveItemIndex.

[Said Abou-Hallawa]

Created attachment 392607 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 392607 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=392607&action=review

Please file a bug to track adding this optimization back.

> Source/WebCore/ChangeLog:3
> +        DisplayList::Save item should not track the index of the corresponding Restore item

This title should be "remove the optimization for..."

[Said Abou-Hallawa]

Created attachment 392614 [details]
Patch

[WebKit Commit Bot]

The commit-queue encountered the following flaky tests while processing attachment 392614 [details]:

editing/spelling/spellcheck-paste-continuous-disabled.html bug 208016 (authors: [e-mail] and [e-mail])
The commit-queue is continuing to process your patch.

[WebKit Commit Bot]

Comment on attachment 392614 [details]
Patch

Clearing flags on attachment: 392614

Committed r257945: <https://trac.webkit.org/changeset/257945>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Radar WebKit Bug Importer]

<rdar://problem/60100226>

[Jacob Uphoff]

Reverted r257945 for reason:

This causes tests to fail

Committed r257947: <https://trac.webkit.org/changeset/257947>

[Simon Fraser (smfr)]

Namely:
displaylists/canvas-display-list.html
displaylists/extent-includes-shadow.html
displaylists/extent-includes-transforms.html

[Said Abou-Hallawa]

(In reply to Simon Fraser (smfr) from comment #9)
> Namely:
> displaylists/canvas-display-list.html
> displaylists/extent-includes-shadow.html
> displaylists/extent-includes-transforms.html

Yes because DisplayList::Restore has no parameters now and operator<<(TextStream& ts, const Item&) should not call operator<<(TextStream& ts, const Save&) because this is going to call itself and we end up in infinite recursion.

[Said Abou-Hallawa]

Created attachment 392635 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 392635 [details]
Patch

Clearing flags on attachment: 392635

Committed r257958: <https://trac.webkit.org/changeset/257958>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.