1244098 - Fold jsop_in to boolean constant.

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Tooru Fujisawa [:arai]]

In bug 887016, jsop_in is used to check String.prototype has no non-default property (@@match, @@search, etc), and it needs to be folded into boolean constant, especially false, in Ion compilation, to improve performance.

it's used like following, so it should be false in normal case.

> function StringHasNoMatch() {
>   var ObjectProto = GetBuiltinPrototype("Object");
>   var StringProto = GetBuiltinPrototype("String");
>...
>   if (std_match in StringProto)
>     return false;
>   return true;
> }

Comment 1

[Tooru Fujisawa [:arai]]

jandem, would you finish the patch you gave me before?

Comment 2

[Jan de Mooij [:jandem]]

Attachment: Patch

This is a cleaned-up version of the patch I gave arai.

It folds "id in object" in IonBuilder, if we know the object (or an object on its prototype chain) does not have the property.

Comment 3

[Jan de Mooij [:jandem]]

Comment on attachment 8715760 [details] [diff] [review]
Patch

Oops, meant to r? Brian.

Comment 4

[Jan de Mooij [:jandem]]

(In reply to Jan de Mooij [:jandem] from comment #2)
> It folds "id in object" in IonBuilder, if we know the object (or an object
> on its prototype chain) does not have the property.

If the object is a singleton, we can also fold if it definitely *has* the property.

I didn't implement that yet, because it's a bit more tricky and the current patch is sufficient for bug 887016.

Comment 5

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/df34cd3d3f88

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/df34cd3d3f88