1353679 - Optimize the Object case in obj_toString

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Jan de Mooij [:jandem]]

Attachment: Patch

This is by far the most common case when we get to the non-standard path, so it's worth checking for it.

Comment 1

[Tom S [:evilpie]]

Comment on attachment 8854777 [details] [diff] [review]
Patch

Review of attachment 8854777 [details] [diff] [review]:
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Nice. Maybe we should atomize all the StringBuffer results.

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Part 2 - Atomize toString result

This atomizes the result of toString. A microbenchmark is about 20% slower, but this will improve other parts of the system (GC, caches) so it seems worth it.

Comment 3

[Tom S [:evilpie]]

Comment on attachment 8854867 [details] [diff] [review]
Part 2 - Atomize toString result

Hard to judge what the best decision here would be, but argument about improving the rest of the VM seems convincing. Although I haven't actually investigated this, I think it's likely a lot of code would do something toString().slice(8, -1) to extract just the actual tag.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/ed9386534ece
part 1 - Optimize the Object case in Object.prototype.toString because it's very common. r=evilpie
https://hg.mozilla.org/integration/mozilla-inbound/rev/23bb7ee563d9
part 2 - Atomize strings returned from Object.prototype.toString to avoid allocating duplicate strings. r=evilpie

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/ed9386534ece
https://hg.mozilla.org/mozilla-central/rev/23bb7ee563d9