1709135 - Change TranscodeRange to iterate over immutable bytes.

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P1)

Description

[Nicolas B. Pierron [:nbp]]

Today TranscodeRange is defined as mozilla::Range<uint8_t>. However Range provide little API compared to Span, and the data which is iterated over should not be mutated.

Therefore, we should change this type to use mozilla::Span<const uint8_t>.

Comment 1

[Ted Campbell [:tcampbell]]

One thing to keep in mind is that mozilla::Span has release-asserts for access (both indexed and iterators). Likely, this is not an issue here since we directly point the CompilationStencil to the backing data, but it is something to keep in mind.

Comment 2

[Nicolas B. Pierron [:nbp]]

Attachment: Bug 1709135 - XDR: Make decoded content immutable.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/86dd0eef1d7a
XDR: Make decoded content immutable. r=arai

Comment 4

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/86dd0eef1d7a

Comment 5

[Alexandru Ionescu (needinfo me) [:alexandrui]]

== Change summary for alert #30074 (as of Thu, 13 May 2021 21:57:19 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
10%	cpstartup (docs)	content-process-startup	linux1804-64-shippable-qr	e10s stylo webrender	111.96 -> 101.17
9%	cpstartup (docs)	content-process-startup	windows10-64-shippable-qr	e10s stylo webrender-sw	97.12 -> 88.58

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=30074

Comment 6

[Andra Esanu (needinfo me)]

== Change summary for alert #30088 (as of Fri, 14 May 2021 11:17:09 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
8%	Base Content Resident Unique Memory		macosx1015-64-shippable-qr		17,574,229.33 -> 16,088,746.67
6%	Base Content Resident Unique Memory		macosx1015-64-shippable-qr		17,732,522.67 -> 16,699,562.67

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=30088