1824203 - Prepopulate Ion ICs based on active baseline stubs

Status: NEW

(Core :: JavaScript Engine: JIT, task, P2)

Description

[Iain Ireland [:iain]]

If there is more than one active stub in a baseline IC (ie the first stub doesn't always succeed), then we generate an Ion IC in WarpBuilder. When we do so, we could consider packaging up the CacheIR for each of the stubs with a non-zero success rate, storing it in the script snapshot, and using it to prepopulate the Ion IC chain. The advantage of this is that we can do the IC compilation offthread, and batch the mprotect for the ICs with the mprotect for the Ion code.

The main obstacle is that we'd have to make sure the Ion CacheIR compiler can safely run offthread.