Has anyone else looked at using Coccinelle/spatch[1] on CPython source code?
It's a GPL-licensed tool for matching semantic patterns in C source code. It's been used on the Linux kernel for detecting and fixing problems, and for autogenerating patches when refactoring (http://coccinelle.lip6.fr/impact_linux.php). Although it's implemented in OCaml, it is scriptable using Python. I've been experimenting with using it on CPython code, both on the core implementation, and on C extension modules. As a test, I've written a validator for the mini-language used by PyArg_ParseTuple and its variants. My code examines the types of the variables passed as varargs, and attempts to check that they are correct, according to the rules here http://docs.python.org/c-api/arg.html (and in Python/getargs.c) It can detect this old error (fixed in svn r34931): buggy.c:12:socket_htons:Mismatching type of argument 1 in ""i:htons"": expected "int *" but got "unsigned long *" Similarly, it finds the deliberate error in xxmodule.c: xxmodule.c:207:xx_roj:unknown format char in "O#:roj": '#' (Unfortunately, when run on the full source tree, I see numerous messages, and as far as I can tell, the others are false positives) You can see the code here: http://fedorapeople.org/gitweb?p=dmalcolm/public_git/check-cpython.git;a=tree and download using anonymous git in this manner: git clone git://fedorapeople.org/home/fedora/dmalcolm/public_git/check-cpython.git The .cocci file detects invocations of PyArg_ParseTuple and determines the types of the arguments. At each matching call site it invokes python code, passing the type information to validate.py's validate_types. (I suspect it's possible to use spatch to detect reference counting antipatterns; I've also attempted 2to3 refactoring of c code using semantic patches, but so far macros tend to get in the way). Alternatively, are there any other non-proprietary static analysis tools for CPython? Thoughts? Dave [1] http://coccinelle.lip6.fr/ _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
