[pypy-dev] Flow graphs, backends and JIT

[haael]

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?

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?

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

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?

haael