jit

The canonical JVM implementation from Sun applies some pretty sophisticated optimization to bytecode to obtain near-native execution speeds after the code has been run a few times. The question is, why isn't this compiled code cached to disk for use during subsequent uses of the same function/class? As it stands, every time a program is executed, the JIT compiler kicks in afresh, rather than using a pre-compiled version of the code. Wouldn't adding this feature add a significant boost to the initial run time of the program, when the bytecode is essentially being interpreted? Without resorting

Are there scenarios where JIT compiler is faster than other compilers like C++? Do you think in the future JIT compiler will just see minor optimizations, features but follow a similar performance, or will there be breakthroughs that will make it infinitely superior to other compilers? It looks like the multi core paradigm has some promise but it's not universal magic. Any insights? Yes, there certainly are such scenarios. JIT compilation can use runtime profiling to optimize specific cases based on measurement of the characteristics of what the code is actually doing at the moment, and can

Both of them pretty much do the same thing. Identify that the method is hot and compile it instead of interpreting. With OSR, you just move to the compiled version right after it gets compiled, unlike with JIT, where the compiled code gets called when the method is called for the second time. Other than this, are there any other differences? Jay Conrod In general, Just-in-time compilation refers to compiling native code at runtime and executing it instead of (or in addition to) interpreting. Some VMs, such as Google V8, don't even have an interpreter; they JIT compile every function that gets

What's the "correct" way to call an absolute pointer in x86 machine code? Is there a good way to do it in a single instruction? What I want to do: I'm trying to build a kind of simplified mini-JIT (still) based on "subroutine threading". It's basically the shortest possible step up from a bytecode interpreter: each opcode is implemented as a separate function, so each basic block of bytecodes can be "JITted" into a fresh procedure of its own that looks something like this: {prologue} call {opcode procedure 1} call {opcode procedure 2} call {opcode procedure 3} ...etc {epilogue} So the idea is