Plenty of them. You don't even need a special language - with the right build system & build rules, you're more than welcome to have e.g. "make" build your generator, run your generator, and then build your generated code.
I occasionally write C# which writes C# (using .NET APIs to compile it at runtime, typically) and C# in T4 Text Templates which write C# (they integrate nicely into Visual Studio's build process right out of the box.)
I occasionally write C# which writes C# (using .NET APIs to compile it at runtime, typically) and C# in T4 Text Templates which write C# (they integrate nicely into Visual Studio's build process right out of the box.)