Just-in-time (JIT) compilation is a technique used in computer science where the compilation of code occurs during the execution of a program instead of before execution. This involves translating bytecode into machine code, which is then executed directly. JIT compilers analyze executed code and identify portions that would benefit from compilation or recompilation, balancing the effort required with the speed gains. This technique is used in runtime interpreters for languages such as JavaScript, C#, and Java to approximate the execution speed of precompiled binary languages like C++.
FAQ about Just-in-Time (JIT) Compilation
If you’re not familiar with just-in-time (JIT) compilation, you might have some questions about how it works and what its advantages are. Here are some frequently asked questions:
What is JIT compilation?
Just-in-time (JIT) compilation is a technique used by runtime interpreters for languages such as JavaScript, C# and Java to approximate the execution speed to the native performance of precompiled binary languages such as C++. JIT compilation involves compilation of source code or byte code during the execution of a program (at runtime) rather than before execution.
How does JIT compilation work?
A system that implements a JIT compiler continuously analyzes the executed code and identifies portions of the code where there would be a speed gain from compilation or recompilation that would outweigh the effort required to compile that code. JIT compilers also perform optimizations that wouldn’t be possible during the ahead-of-time (AOT) compilation process, such as inlining of frequently used functions and removal of dead code.
What are the advantages of JIT compilation?
JIT compilation offers several advantages over AOT compilation. First, since code is compiled at runtime, the compiler has more information about the environment in which the code is executing and can produce more optimized code. Second, JIT compilation enables runtime profiling of code, allowing the system to identify frequently used code paths and optimize those paths. Finally, JIT compilation can speed up the execution of a program by reducing the amount of time spent waiting for compilation to complete.
What are the use cases of JIT compilation?
JIT compilation is primarily used in runtime interpreters for languages such as JavaScript, C#, and Java. These languages are typically used for web applications and other performance-critical applications where performance is important. JIT compilation allows these languages to approach the performance of precompiled binary languages such as C++.
JIT compilation is also used in other contexts, such as in the .NET platform, where it is used to generate code that runs on multiple platforms.
The heart
Just-in-time (JIT) compilation is an important technique for improving the performance of runtime interpreters for languages such as JavaScript, C#, and Java. By compiling code at runtime, JIT compilers are able to produce more optimized code that approaches the performance of precompiled binary languages such as C++. JIT compilation offers several advantages over AOT compilation, including runtime profiling of code and reduction of the time spent waiting for compilation to complete.
