jit

I've been thinking about it lately, and it seems to me that most advantages given to JIT compilation should more or less be attributed to the intermediate format instead, and that jitting in itself is not much of a good way to generate code. So these are the main pro-JIT compilation arguments I usually hear: Just-in-time compilation allows for greater portability. Isn't that attributable to the intermediate format? I mean, nothing keeps you from compiling your virtual bytecode into native bytecode once you've got it on your machine. Portability is an issue in the 'distribution' phase, not

I've been hearing a lot about the PyPy project. They claim it is 6.3 times faster than the CPython interpreter on their site . Whenever we talk about dynamic languages like Python, speed is one of the top issues. To solve this, they say PyPy is 6.3 times faster. The second issue is parallelism, the infamous Global Interpreter Lock (GIL). For this, PyPy says it can give GIL-less Python . If PyPy can solve these great challenges, what are its weaknesses that are preventing wider adoption? That is to say, what's preventing someone like me, a typical Python developer, from switching to PyPy right

I find the practice of caching an array's length property inside a for loop quite distasteful. As in, for (var i = 0, l = myArray.length; i < l; ++i) { // ... } In my eyes at least, this hurts readability a lot compared with the straightforward for (var i = 0; i < myArray.length; ++i) { // ... } (not to mention that it leaks another variable into the surrounding function due to the nature of lexical scope and hoisting.) I'd like to be able to tell anyone who does this "don't bother; modern JS JITers optimize that trick away." Obviously it's not a trivial optimization, since you could e.g.

Microsoft recently released tools and documentation for its new Phone 7 platform, which to the dismay of those who have a big C++ codebase (like me) doesn't support native development anymore. Although I've found speculation about this decision being reversed, I doubt it. So I was thinking how viable would be to make this codebase available to Phone 7 by adapting it to compile under C++/CLI. Of course the user interface parts couldn't be ported, but I'm not sure about the rest. Anyone had a similar experience? I'm not talking about code that does heavy low-level stuff - but there's a quite

I know that Java's HotSpot JIT will sometimes skip JIT compiling a method if it expects the overhead of compilation to be lower than the overhead of running the method in interpreted mode. Does the .NET CLR work based upon a similar heuristic? Note: this answer is on a "per-run" context. The code is normally JITted each time you run the program. Using ngen or .NET Native changes that story, too... Unlike HotSpot, the CLR JIT always compiles exactly once per run. It never interprets, and it never recompiles with heavier optimisation than before based on actual usage. This may change, of course,