Web Apocrypha

It is well known that runtime profiling is handy when we want to measure the runtime cost of different functions, identify the performance bottlenecks of the code, or measure the progress of the project over a period. However, most profiling mechanisms are tied to a specific project, which makes the comparison of different solutions impossible. I have developed a simple library, which can easily be added to any existing JIT engine. The attached tgz contains patches for wide-spread JIT engines (namely WebKit-JavaScriptCore and Tamarin-NanoJIT).

NanoJIT is developed as a sub-project of the Tamarin ActionScript virtual machine. It is a lightweight JIT compiler, which produces machine code from a Low-level Intermediate Language (called LIR). LIR instructions are inspired by Register Transfer Languages. Furthermore, NanoJIT has already been ported to several architectures like x86, ARM and powerpc. However, SquirellFish Extreme, the JavaScript jit compiler of WebKit has taken another approach.