jit

Possible Duplicate: JIT compiler vs offline compilers I have heard that under certain circumstances, Java programs or rather parts of java programs are able to be executed faster than the "same" code in C++ (or other precompiled code) due to JIT optimizations. This is due to the compiler being able to determine the scope of some variables, avoid some conditionals and pull similar tricks at runtime. Could you give an (or better - some) example, where this applies? And maybe outline the exact conditions under which the compiler is able to optimize the bytecode beyond what is possible with

So when CLR runtime load a .NET assembly, it compiles it into machine native code. This process is called JITing. NGen is also the process of compiling .NET assembly into native code. I don't understand what is the difference between two? The difference is when they occur. The JIT compilation occurs while your program is running. NGen is a typically done at installation time of your program and happens before your program is run. One of the goals of NGen is to remove the JIT penalty from application start up. JIT is only done per-method; it doesn't JIT everything... Only the bits you need. Of

I have generated a bc file with the online compiler on llvm.org, and I would like to know if it is possible to load this bc file from a c or c++ program, execute the IR in the bc file with the llvm jit (programmatically in the c program), and get the results. How can I accomplish this? Here's some working code based on Nathan Howell's: #include <string> #include <memory> #include <iostream> #include <llvm/LLVMContext.h> #include <llvm/Target/TargetSelect.h> #include <llvm/Bitcode/ReaderWriter.h> #include <llvm/ExecutionEngine/ExecutionEngine.h> #include <llvm/ModuleProvider.h> #include <llvm

I was just watching the Google IO videos and they talked about the JIT compiler that they included in the android. They showed a demo of performance improvements thanks to the JIT compiler. I wondered what does exactly a JIT compiler do and wanted to hear from different people. So, what is the duty of a JIT compiler? Java code is normally distributed as bytecode, which is machine-independent pseudocode . (The same idea was previously used in UCSD-p system developed in the 70'ies.) The advantage of this is that the same application can be run in different processors and operating systems. In

What are the differences between a Just-in-Time-Compiler and an Interpreter, and are there differences between the .NET and the Java JIT compiler? Just-in-time compilation is the conversion of non-native code, for example bytecode, into native code just before it is executed. From Wikipedia: JIT builds upon two earlier ideas in run-time environments: bytecode compilation and dynamic compilation. It converts code at runtime prior to executing it natively, for example bytecode into native machine code. An interpreter executes a program. It may or may not have a jitter. Again, from Wikipedia: An

I'd like to write a very small proof-of-concept JIT compiler for a toy language processor I've written (purely academic), but I'm having some trouble in the middle-altitudes of design. Conceptually, I'm familiar with how JIT works - you compile bytecode into (machine or assembly?) code to run. At the nuts-and-bolts level however, I'm not quite gripping how you actually go about doing that. My (very "newb") knee-jerk reaction, since I haven't the first clue where to start, would be to try something like the following: mmap() a block of memory, setting access to PROT_EXEC write the native code

I'm toying with the idea of writing a JIT compiler and am just wondering if it is even theoretically possible to write the whole thing in managed code. In particular, once you've generated assembler into a byte array how do you jump into it to begin execution? Gene Belitski And for the full proof of concept here is a fully capable translation of Rasmus' approach to JIT into F# open System open System.Runtime.InteropServices type AllocationType = | COMMIT=0x1000u type MemoryProtection = | EXECUTE_READWRITE=0x40u type FreeType = | DECOMMIT = 0x4000u [<DllImport("kernel32.dll", SetLastError=true)