974350 - Optimize CreateRegExpMatchResult

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

Attachment: Patch

CreateRegExpMatchResult uses an AutoValueVector. It can store up to 8 values inline, but Octane-regexp often stores up to 12 values, so we have to malloc/free external elements.

We could templatize AutoValueVector and bump the number of inline elements to 12, but this patch just gets rid of the AutoValueVector completely and fills the array directly.

This is a small win on Octane-regexp and is also simpler I think.

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Part 2 - More cleanup

There's some code in CreateRegExpMatchResult to deal with input == nullptr. In that case we allocate a string from chars + length.

It looks like ExecuteRegExpLegacy is the only caller that can pass a nullptr input, so we can move this check there and eliminate some code/args from the hot path.

Patch also removes some unnecessary roots.

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Part 3 - Inline getOrCreateMatchResultTemplateObject

Profile shows 0.4% or so under getOrCreateMatchResultTemplateObject called from CreateRegExpMatchResult.

With this patch we inline the common matchResultTemplateObject_ != nullptr case. It's a puny win but simple to do.

Comment 3

[Jan de Mooij [:jandem]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/76618fcca721
https://hg.mozilla.org/integration/mozilla-inbound/rev/6e3f7835fa62
https://hg.mozilla.org/integration/mozilla-inbound/rev/dc46d95c4787

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/76618fcca721
https://hg.mozilla.org/mozilla-central/rev/6e3f7835fa62
https://hg.mozilla.org/mozilla-central/rev/dc46d95c4787

Comment 5

[Hugh Nougher [:Hughman]]

GGC octane-regexp appears to be 10% faster according to AWFY.
Some improvement in GGC splay also.