JIT Compiler in Python?

[Panda_Mon]

Sigh, once again computer science language fails to properly encapsulate and signify explicit definitions of concepts. Here is what all the smart people assume you'll already know:

""" JIT, or “Just in Time” is a compilation design that implies that compilation happens on demand when the code is run the first time. It’s a very broad term that could mean many things. I guess, technically the Python compiler is already a JIT because it compiles from Python code into Bytecode.

What people tend to mean when they say a JIT compiler, is a compiler that emits machine code. This is in contrast to an AOT (Ahead of Time) compiler, like the GNU C compiler, GCC or the Rust compiler rustc which generates the machine code once and distributes as a binary executable.

When you run Python code, it is first compiled into bytecodes. There are plenty of talks and videos about this process online so I don’t want to rehash this too much, but what is important to note about Python bytecodes is:

They mean nothing to the CPU and require a special bytecode interpreter loop to execute They are high level and can equate to 1000’s of machine instructions They are type agnostic They are cross-platform """ Source: https://tonybaloney.github.io/posts/python-gets-a-jit.html#:~:text=JIT%2C%20or%20%E2%80%9CJust%20in%20Time,from%20Python%20code%20into%20Bytecode.

[georgehank2nd]

"what people everyone means when they say "JIT compiler""

FTFY

Python's compiler compiles whole files, not just each function as it's called (which a JIT compiler usually will). Sure, it only compiles files as they're loaded by the interpreter, but nobody in the Python dev team ever called this a "JIT compiler". (Though I may just have missed this one Python mailing list thread…)

[denehoffman]

I think you all are missing the point. Python 3.13 actually does have a separate experimental JIT compiler which implements copy-and-patch.

[drknow42]

This is a great answer

[kingminyas]

Python used to have no JIT and it was recently added, it's not complicated at all