Insure++

For the last four years I have worked as a programmer writing software to find errors in integrated circuit designs. During this time I have learned a lot about chasing bugs. Ideally, you want to find and fix a program's bugs before you ship it to your customers. Remarkably, customers seem to be extremely creative people who can figure out how to use (and break) programs in ways programmers have never foreseen.

In order to combat the “creative user” problem, there is a type of program which will take source code or object files and produce a version that analyzes itself for bugs as it runs. The wonderful thing about this type of program is that it allows you to find bugs that are not causing any visible problems, so that you can fix them before they cause anyone trouble. We have found these programs to be invaluable at work.

Parasoft Corporation produces one of these programs, which they market under the name of Insure++. We recently evaluated the Solaris version of Insure++ at work, and I was excited to learn that they also had a Linux version.

A few weeks later I got e-mail from a sales person at Parasoft. She introduced herself and offered to put me in touch with their programmers if I had any technical problems. She went on to tell me that their product currently only worked with libc5 and not glibc, but that they were working on glibc support. I was impressed with both her helpful attitude, and the fact that she knew about glibc, which had only been available for two months.

A few days later Insure++ arrived at my house. The box contained a CD-ROM, a 10-page booklet with installation instructions and a 500-page user's manual. I had the software installed on the computer within five minutes, even though I had one minor problem with their installation script. I then called Parasoft to get a license key. I was very impressed with the salesperson who answered. After he gave me the key, he helped me create a $HOME/.psrc file, the startup file for Insure++, and he walked me through one of the examples included on the CD-ROM. Then he showed me a few features of the product and gave me his telephone extension and told me to call him if I had any problems.

Insure++ operates by taking your C or C++ source code and creating a new file which contains your code plus some automatically generated statements. The purpose of these statements is to analyze how your program is using memory, function calls and variables, so that potential problems can be found. Insure++'s analysis is extremely detailed. It knows when you use uninitialized variables or memory. It knows when there are no longer any pointers to allocated memory (leaks). It knows when you reference past the end of an array or structure. It knows when you call functions improperly. And it knows even more. Insure++'s analysis is also very robust. It can handle programs that use threads and programs that use memory obtained from files created by mmap or SysV shared memory objects.

Insure++ is also easy to use. Instead of compiling your program with gcc, you compile and link it with a program called insure. The insure compiler takes care of generating the modified source files, compiling them with gcc and then deleting them. It also does compile-time error checking. After the program is compiled you run it in the normal fashion, and it runs as normal, except that it is analyzing itself for errors. Errors found at compile or run time can be logged to a file, to stderr or to stdout, and error messages can be customized in order to be interpreted by programs such as Emacs. The default behavior is to send error messages to an X11-based program called Insra. Insra displays the error messages in an easy-to-understand manner, and it acts as an interface with your editor. Insra can also save the errors, allowing you to reload them and fix the problems later.

Most programs are not completely self-contained. Instead, they use code from system libraries like the C library or the X11 library. In order to fully check your program for errors, these libraries must be compiled with insure. Since most people have no interest in recompiling something like the X11 library, Insure++ comes with precompiled versions of several system libraries including libc, libm, libX11, libXaw, libXt and libdlsym. If you need to use a library that's not included with Insure++, and you can't or don't want to recompile it yourself, you can just link with the standard library. Insure++ will still be able to do some error checking of the library functions, but it will not be as detailed or complete as it would be if the library compiled with insure.