1870391 - Improve performance of early Baseline-compilation of self-hosted code

Status: NEW

(Core :: JavaScript Engine, task, P3)

Description

[Bryan Thrall [:bthrall]]

Performance comparison results from bug 1827914 indicate that we're keeping self-hosted code longer in Baseline rather than compiling it to Ion. We should investigate and see if we can improve the Speedometer3 results.

Potential causes include:

• Interaction with Jit Hints - e.g. if we never "enter baseline" for self-hosted code because we're already in it, maybe the hints are different
• Entering baseline before it heats up, so it takes longer for the counter to reach the point where it compiles to Ion

It's also interesting that the Baseline-compiled bytecode is being discarded twice for every GC. It might make sense to just never discard these self-hosted baseline scripts, like we do with trampolines or the baseline interpreter. Tweaking this line might be sufficient.