Csmith

What Csmith is

Csmith is a free C program generator for finding compiler bugs through differential testing. It creates random C programs that are free of undefined behavior and includes statistics with each generated program. A documented workflow uses GCC and Clang to compile generated programs, then compares their outputs to look for differences. Csmith can also supply programs for a C test suite when users do not want to write one themselves.

Command-line options displayed by `csmith -h` and `csmith -hh` let users customize generation. The tool runs locally and supports Linux and Windows. The project documents Windows builds with Visual Studio or WSL; its Ubuntu instructions name g++, CMake, and m4 as prerequisites for building from source with CMake and make. The INSTALL file says Csmith should build on most modern machines with a C++ compiler. Generated programs may run indefinitely, so the README recommends timeouts during execution. The repository includes a COPYING license file. GitHub issues are available for bug reports and suggestions, and a mailing list supports discussion. Maintainers say replies may be delayed because they maintain the project in their discretionary time.

Who it suits

Csmith suits compiler developers and testers who need generated C programs for differential testing or want material for a C test suite. It is also relevant to users who can build and run command-line software locally on Linux or Windows.

Getting started

1. Open the Csmith GitHub repository.
2. Choose a Linux or Windows build route.
3. On Ubuntu, install g++, CMake, and m4, then use CMake and make to build from source.
4. On Windows, build with Visual Studio or WSL.
5. Use `csmith -h` or `csmith -hh` to inspect generation options.
6. Compile generated programs with GCC and Clang and compare their outputs; apply timeouts when executing them.

Verdict

Choose Csmith when you need locally generated C programs for compiler comparisons or test-suite creation. Timely maintainer responses are not assured.