945437 - Fix Compile usecount check

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Jan de Mooij [:jandem]]

Attachment: Patch

We should call UsesBeforeIonRecompile() instead of using js_IonOptions.usesBeforeCompile. Problem with the latter is that we can Ion-compile large scripts too eagerly when called from the interpreter/VM.

This seems to win 1000 points or so on Octane-mandreel. It fixes an issue where a pretty big Ion script is immediately invalidated when it runs due to incomplete type information for the non-OSR entry point. Hannes, I think this also affects bug 939614.

Comment 1

[Hannes Verschore [:h4writer]]

Comment on attachment 8341271 [details] [diff] [review]
Patch

Review of attachment 8341271 [details] [diff] [review]:
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I already wondered why we used different tests for checking IonCompile is ready to compile or when baseline decides when to compile. But at the time I reasoned this wouldn't occur. But indeed a very cold script (usecount < 10) calling such a problem case script will not use the right usecount.

Good find!

Comment 2

[Jan de Mooij [:jandem]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/19bfb5a02699

Comment 3

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/19bfb5a02699