A sidenote on JIT: I wrote the following while working out the structure of my post; I figured it wouldn't hurt too much to post it too. The bulk of my question

A sidenote on JIT: I wrote the following while working out the structure of my post; I figured it wouldn't hurt too much to post it too. The bulk of my question is above; what follows is more or less incidental. I understand that JIT has something of a role in performance, and that modern Javascript engines couple the performance gains of JIT execution with a mind-boggling slew of different security and sandboxing techniques that aim to prevent unwanted data colliding with the CPU's instruction pointer while still allowing near-C levels of performance. Thing is, what generally makes browsers' sometimes unbelievable JIT-powered performance[1] possible is the fact that the major JS engines - V8, JavaScriptCore, Chakra, Spidermonkey - have huge companies behind them that have the resources to fund continuous R&D to iterate on performance while keeping abreast of security issues. [1]: http://www.gopherjs.org/blog/2015/09/28/surprises-in-gopherjs-performance/ http://www.gopherjs.org/blog/2015/09/28/surprises-in-gopherj... But I'm not a browser manufacturer, or a computer science major (or even undergrad). I'm just a tinkerer who wants to play around with ideas that generally need safe remote code execution in a way that is transparent (to the extent a high-level competent end user could introspect all operations and control low-level settings) and trustable (for both the end user, who wants control of their device, and the developer, who wants a predictable environment). I understand that JIT is generally incredibly hard to get right - this LuaJIT punchthrough[2] is an enlightening read (if just to learn what involved Lua code can look like :P) - and that once you flip the execute bit on any of the memory the OS has allocated it's basically game on to start juggling how much to hypervise so performance doesn't get hit too much. [2]: http://www.corsix.org/content/malicious-luajit-bytecode http://www.corsix.org/content/malicious-luajit-bytecode The Web also has a mind-boggling churn rate, which can be offputting in some contexts/situations that favor stability and consistency.