[DerekL]

Apps can use JavaScriptCore, and JavaScriptCore can use JIT, but these can't happen together, because third-party apps aren't permitted to execute writeable memory.

http://stackoverflow.com/questions/22281265/is-javascriptcor...

[andrewjl]

This is good to know. Looks like the only way to make use of JIT (by someone who isn't Apple) is to use a WKWebView to execute the JS.