1134611 - Optimize Object.defineProperty

Status: VERIFIED DUPLICATE of bug 1303335

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

See the micro-benchmark below. We're a good bit faster than V8, but JSC is way faster than us:

Safari: 186 ms
SM:     496 ms
d8:     848 ms

A profile shows there are some things we can optimize, and maybe we could self-host parts of defineProperty, but we should also see what JSC is doing here exactly.

This affects the Ember Object.create benchmark (bug 1097376).

var name = "Foo";
var desc = {configurable:true, writable:true, enumerable:false, value:null};
function f() {
    var t = new Date;
    for (var i=0; i<1000000; i++) {
	globalO = {};
	Object.defineProperty(globalO, name, desc);
    }
    print(new Date - t);
}
f();

Comment 1

[Tom S. (please needinfo tschuster)]

Attachment: Use pure version for lookup

It's really unfortunate that NativeHasProperty and NativeGetProperty seems to be relatively slow.

410 -> 319

Comment 2

[Tom S. (please needinfo tschuster)]

Attachment: Use pure version for lookup

Comment 3

[Guilherme Lima]

Is this a dupe of bug 772334?

Comment 4

[André Bargull [:anba]]

(In reply to Jan de Mooij [:jandem] from comment #0)
> A profile shows there are some things we can optimize, and maybe we could
> self-host parts of defineProperty, [...]

Bug 1303335 has a WIP patch to self-host Object.defineProperty (and Object.getOwnPropertyDescriptor).