[Cython] Fwd: Re: GCC Python FE

Stefan Behnel stefan_ml at behnel.de
Sun Jul 3 20:33:13 CEST 2011


just got this back as a reply from the author of a GCC Python frontend. 
This project flew completely below my radar so far, even though it's the 
second GSoC being invested here.

 From the Python wiki page, it looks like static Python compilers are 
starting to sum up these days. IMHO, it would be better to get these 
consolidated a bit, rather than having people reinvent wheels all over the 



-------- Original-Message --------
Subject: Re: GCC Python FE
From: Philip Herron <herron.philip (at) googlemail.com>

On 3 July 2011 16:57, Stefan Behnel wrote:
> I just stumbled over this wiki page:
> http://gcc.gnu.org/wiki/PythonFrontEnd
> I'm a Cython core developer, and as such, I wonder what the purpose of this
> project was, and what it lead to.

Well i was inspired by PHC http://www.phpcompiler.org/ which was a
similar idea but for php, the purpose was mostly i though it was
interesting and wanted to see how feasible it is to do something like
this plus i wanted to learn more, i've written compilers for simple
more static languages and made my own interpreter before and the buzz
word at the moment seems to be jit compilers but i still think
compiling like this could still be a good step forward at least for my
understanding. And in the end it could possibly open up different
opportunities to use python in a different way be it on low memory
systems or even a different way of embeding python into programs but
we will see how feasible that is when its more mature.

Well last year gsoc 2010 i spent mostly figuring out how i was going
to implement a lot of things and getting more comfortable with GCC
internals. But i am currently doing this for gsoc 2011 again

> The project is marked as "part of GSoC 2010", so I guess there was some kind
> of outcome. Could you give me an idea of how it went and what was achieved?

Well from last year's Gsoc i successfully got dynamic typing working,
but its mostly similar to how cython does it, by wrapping things into
the py_obect_ type where it stores the data and has hooks to its
binary protocol and other standard hooks like print and destory etc or
whatever it is, haven't looked at the cython code in sometime.

Dynamic typing is kind of handled at runtime still because i cant
really avoid it, but i am happy that i am working on a constant
folding pass because i cant rely on gcc's own constant folding code to
handle this because i have to handle it in my own front-end IL. But
besides that i am working on object orientation and calls at the
moment. Where i take something like:

class foo:
   def __init__ (self)
     self.x = 1

And have to generate the type then generate the methods like:

struct main.foo {
   gpy_object_t * x;

gpy_object_t * main.foo.__init__ (struct main.foo * self)
   self->x = fold_int (1);


So i am just wrapping it into a normal object like you would in any
other language because its fairly trivial its awkward in that python
you can do self->x where x wasn't pre-declared it seems so i have to
iterate several passes over my IL so i can generate the type then
generate the methods.

But this is all currently being worked on its mostly done just
cleaning up lots of code and fixing some bugs leaving polymorphism for
now will work on it when i come to it but i am more worried about how
i will get calls working and imports across multiple files. But i am
planning on using GCC's LTO to help me get around that, since at link
time i have the opportunity to see code from everywhere to figure out
where calls should be placed etc. But i wont get time to work on that
for a few weeks yet as i need to finish what i am doing first. I am
fairly happy with what i have achieved so far as its a lot of work for
me on my own to do in 2 summers although i spent a lot of time though
my university work just thinking how i will make things work so i can
concentrate on implementation now.

Its mostly a passion of mine but in the end i just want to understand
things more and it seems this has taught me alot of how dynamic
languages work and i enjoy it so i keep working on it. Although
university is nearly over so i guess i will need to find a job xD lol.

Hope this answers your questions feel free to ask more if your interested. :)


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