1879743 - Rewrite custom property substitution to avoid re-tokenization.

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, task)

Description

[Emilio Cobos Álvarez (:emilio)]

This helps with bug 1850809.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1879743 - Rewrite custom property substitution to avoid re-tokenization. r=zrhoffman,dshin,#style

This speeds up custom variable substitution by avoiding re-tokenizing,
and variable reference parsing by avoiding doing duplicate work.

This is a very noticeable improvement in the NewsSite subtests of
speedometer 3 (see comparison posted in bug 1879318 and the #perf-sp3
matrix channel). But it also probably helps most websites using lots of
variables, and the browser UI itself.

Finally, it also avoids some duplication. Now regular substitution and
fallback substitution is handled uniformly, which causes a progression
in some properties-and-values tests.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/13676fc9b0cd
Rewrite custom property substitution to avoid re-tokenization. r=zrhoffman,firefox-style-system-reviewers

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Here's a more up-to-date comparison with the latest version of the patch, still showing the progression: https://treeherder.mozilla.org/perfherder/compare?originalProject=try&originalRevision=970e5c74c608be1b96599215e9e1a71e5a7ee721&newProject=try&newRevision=11edd8eb0b3ac80c195fc825f472d0062d728c44

Comment 4

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/13676fc9b0cd