1859306 - Optimize calls to EqualStringsHelperPure

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, task, P1)

Description

[Jan de Mooij [:jandem]]

This is called a few million times on Speedometer 3, almost always with a non-rope string.

At least in Ion we should be able to do much better. Because we know the JSAtom* we can inline the character comparison for short-ish atoms, similar to what we do with LCompareSInline.

Comment 1

[André Bargull [:anba]]

Attachment: Bug 1859306 - Part 1: Move string character comparison methods into MacroAssembler. r=jandem!

Move CompareCharacters into MacroAssembler and split it into three methods:

• loadStringCharsForCompare() loads the string characters in preparation for
  the comparison. LCompareSInline and LStringStartsWithInline directly pass
  the string characters to compareStringChars. LStringEndsWithInline first
  moves the pointer to the suffix string.
• compareStringChars() and branchIfNotStringCharsEquals() perform the actual
  comparison. Atom comparison in part 2 will only use branchIfNotStringCharsEquals().

Comment 2

[André Bargull [:anba]]

Attachment: Bug 1859306 - Part 2: Compare short atoms using inline assembly. r=jandem!

Compare short atoms using the new branchIfNotStringCharsEquals() method
from part 1.

Depends on D191268

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/563f37a40f9b
Part 1: Move string character comparison methods into MacroAssembler. r=jandem
https://hg.mozilla.org/integration/autoland/rev/179a0f04f520
Part 2: Compare short atoms using inline assembly. r=jandem

Comment 4

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/563f37a40f9b
https://hg.mozilla.org/mozilla-central/rev/179a0f04f520

Comment 5

[Mayank Bansal]

Some AWFY-SP2 improvements :

1% on EmberJS-Debug-TodoMVC: https://treeherder.mozilla.org/perfherder/graphs?highlightAlerts=1&highlightChangelogData=1&highlightCommonAlerts=0&selected=3912859,1777435455&series=mozilla-central,3735814,1,13&series=autoland,3912859,1,13&timerange=5184000&zoom=1697597049177,1698132126416,588.0533846532597,672.1170503058154