Finding division by zero in a big project

Question

Recently, our big project began crashing on unhandled division by zero. No recent code seems to contain any likely elements so it may be new data sets affecting old code. The problem is the code base is pretty big, and running on an embedded device with no comfortable debug access (debug is done by a lot of printf()s over serial console, there is no gdb for the device and even if there was, the binary compiled with debug symbols wouldn't fit).

The most viable way would likely be to find all the division operations (they are relatively infrequent), and analyze code surrounding each of them to see if any of the divisor variables was left unguarded.

The question is then either how to find all division operations in a big (~200 files, some big) C++ project, or, if you have a better idea how to locate the error, please give them.

extra info: project runs on embedded ARM9, a small custom Linux distro, crosscompiled with Cygwin/Windows crosstools, IDE is Eclipse but there's also Cygwin with all the respective goodies. Thing is the project is very hardware-specific, and the crashes occur only when running at full capacity, all the essential interconnected modules active. Restricted "fault mode" where only bare bones are active doesn't create them.

Answer 1

I think the most direct step, would be to try to catch the unhandled exception and generate a dump or printf stack information or similar.

Take a look at this question or just search in google for info relating to exception catching in your particular environment.

By the way, I think that the division could happen as a result of a call to an external library, so it's not 100% sure that you'll find the culprit just by greping your code.