1. A method, comprising: receiving, on a computing device, a request to compile a first program with a scalar callee function and vectorization annotations; and compiling, on the computing device, in response to the request, the first program; wherein compiling the first program includes generating one or more vectorized versions of the scalar callee function based at least in part on the vectorization annotations, and generating one or more vectorized function signatures respectively associated with the one or more vectorized versions of the scalar callee function; and wherein the one or more vectorized function signatures are configured to enable an appropriate one of the one or more vectorized versions of the scalar callee function to be matched and invoked for a generic call from a caller function of a second program to a vectorized version of the scalar callee function.