Flags to debug python C extensions.

I often find myself debugging python C extensions from gdb, but usually some variables are hidden because aggressive optimizations that distutils sets by default. What I did not know, is that you can prevent those optimizations by passing flags -O0 -fno-inline to gcc in keyword extra_compile_args (note: this will only work in GCC). A complete example would look like:

config.add_extension('foo',
sources=['a.c'],
# add this for gdb debug
extra_compile_args=['-O0 -fno-inline'])

and your extension becomes much easier to debug from gdb.

This entry was posted on Wednesday, August 18th, 2010 at 1:40 pm and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

5 Responses to “Flags to debug python C extensions.”

Lorenzo
August 18th, 2010 17:38
1

Nice tip!
Matthieu Brucher
August 19th, 2010 12:16
2

You may also want to add ‘-g’ even in testing release builds
ross
August 19th, 2010 16:59
3

-O0 can cause some other issues. -O1 is typically a better choice if the code is moderately or more complex.
Åsmund Hjulstad
August 24th, 2010 13:34
4

What about fortran extensions, is there any way of sending these options (or -pg) to gfortran?
Joyelle
May 10th, 2011 14:20
5

You’re the gretaset! JMHO