jit

Suppose I generate a C program during execution time: source = "int add_x_y(int x, int y){ return x + y; }"; source_size = 42; I want the following function: void* compile(char* source, int source_size); Such that: int (*f)(int,int) = compile(source, source_size); printf("%d\n",f(2,3)); Outputs: 5 And compile can't depend on external tools (compilers), as I'd like to use it in emscripten (which converts a C program to a .js file). Is that possible? Someone else can probably fill in some of the specifics better than I, but if you don't mind calling out to GCC or linking to it, it should be

Since so there are so many JIT implementation out there, every JIT emits native code. Then why hasn't someone made a tool like JIT2EXE, to save the native code to a native executable? The question is kind of vague as you have not clearly specified what language you are talking about, in my area of .NET, the .NET executables are pre-jitted at runtime in order to speed up the loading times. The code can be generated to native code by a process known as NGEN which takes the .NET IL code and converts it in the process of a binary in which can be understood by the processor. Usually NGEN code are

JIT compilers, by definition, generate code on the fly for execution. But in, say, Windows, we have all kinds of protection that prevent self modifying code or executing from data memory (DEP). So how is it possible for JIT compilers to generate code on the fly? They ask the OS for some memory which is readable, writeable and executable. e.g. you can allocate such memory using mmap() with PROT_READ | PROT_WRITE | PROT_EXEC (POSIX), or VirtualAlloc() with PAGE_EXECUTE_READWRITE (Windows). For a real example, see LLVM's llvm::sys::Memory::AllocateRWX ( Unix implementation ; Windows

I am getting this error in my event logs for a service I put into production: An unhandled win32 exception occurred in RivWorks.FeedHandler.exe [5496]. Just-In-Time debugging this exception failed with the following error: Debugger could not be started because no user is logged on. I have it installed and running under a Win NT global account. I have no idea why it is trying to drop into debugging mode. It was built under the Release model. Running on the 4.0 Framework. When I run on my dev machine, via an EXE entry point instead of the WinSvc entry point, everything runs just fine - BUT - I

Why is the "someValue" variable which is readonly (but we still can change its value via reflection) output as "10", although it actually did change to 55? static class Program { static readonly int someValue = 10; static void Main(string[] args) { Console.WriteLine(someValue); // 10 typeof(Program) .GetField("someValue", BindingFlags.Static | BindingFlags.NonPublic) .SetValue(null, 55); // change readonly field via reflection to 55 Console.WriteLine(someValue); // output in console 10, // but in visual studio debugger it shows 55 Console.ReadKey(); } } Probably just a JIT optimization to