1972572 - Support baking in constant object property values

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P3)

Description

[Jan de Mooij [:jandem]]

We want to support baking in constant property values (for properties that haven't been mutated) of certain objects in Ion. In particular prototype objects and some other objects such as Math and maybe the global.

This will reduce the number of guards for calls such as array.join(). We currently guard on (1) the receiver shape (2) the Array.prototype shape (3) the property value (to ensure we call the expected join function). With this optimization we should be able to turn (2) into an invalidation constraint and then eliminate guard (3) through constant folding.

Comment 1

[Jan de Mooij [:jandem]]

Using size M for an initial version but this could also be L.

Comment 2

[Iain Ireland [:iain]]

I don't think we currently have any concrete plans for more work here. Our initial implementation is complete; we can open new bugs if we do any follow-ups.