[pypy-dev] Flow graphs, backends and JIT

[Benjamin Peterson]

2012/9/16 haael <haael at interia.pl>:
>
> OK, I read almost all the documentation I found on the web page. But I still
> don't understand few things.
>
> There are 3 layers in the whole picture. The user application written in
> Python, the Python interpreter written in RPython and the RPython
> interpreter itself.
>
> 1. Where do flow graphs are generated from? Is it the representation of the
> user application, or the interpreter?

The interpreter.

>
> 2. Where does the JIT fit here? I read it traces the execution of the
> iterpreter and indirectly the user application. Does it operate on the flow
> graphs or something else?

It operates on a serialized version of the flowgraphs.

>
> 3. Which component actually does the JIT? Is it just a tweak on the code
> generator or are the flow graphs generated differently?

The flow graphs are taken from the translator and modified by the JIT generator.

>
> 4. Is there some documentation how to write a backend (code generator)? The
> source code is poorly documented and the topic is not mentioned on the web
> page. What exactly do I need to implement to have a backend?

You mean a JIT backend or a RPython backend?

You might find this useful: http://www.aosabook.org/en/pypy.html

-- 
Regards,
Benjamin