Obtaining the Python Control Flow Graph

[brianlum at gmail.com]

Hi,

I have been looking for a good way to convert python code into a
control flow graph.

I know of Python functions that will convert an expression into an
abstract syntax tree (i.e. ast = parser.expr('(x+5)*5') then t =
ast.totuple() then t), but I am not sure how to obtain a CFG.

I've gone through the compiler and it has code that converts the AST
into a CFG (described here:
http://www.python.org/doc/peps/pep-0339/#ast-to-cfg-to-bytecode).
Basically, PyAST_Compile() in Python/compile.c coverts the AST to a CFG
and outputs final bytecode from the CFG by calling two functions:
PySymtable_Build() in Python/symtable.c and compiler_mod() in
Python/compile.c. PySymtable_Build() will build a symtable and
compiler_mod() will create the CFG.

PyPy also offers a way to obtain a control flow graph:
http://codespeak.net/pypy/dist/pypy/doc/objspace.html#the-flow-model

I was wondering if anyone had any advice on the best way to obtain a
control flow graph.  I need the control flow graph because I am trying
figure out if there is a way to bound the integer ranges and list
lengths at compile time.

Thank you for your help