They are from the LLVM projects, but the integration is very well done. This is something that I miss a lot in Visual Studio, and that makes me consider it as inferior to XCode.
They're part of the LLVM project.
Yeah, Xcode is ‘just’ passing -fsanitize=foo flags to Clang and putting a GUI on top of the error messages that the sanitized binaries output.
Whether you’re using Xcode or not, in my experience Clang’s sanitizers are enormously helpful. They’re also available in GCC…