If you have to compile a high level language L to wasm you could follow many paths, for example L to C, C to wasm, or L to Lisp, Lisp to wasm. I should suggest to create a graph in which vertices are languages and edges are labeled with the efficiency of translation. This way one could use graph theory to select the best path. This is only the ground idea. At a second step one could study what features of languages are main ingredients of that efficiency and design a middleware high level language M for the translation to wasm: L -> M -> wasm. Or weight the translation using a vector of features (concurrency, speed, bugs reports, etc) and select the path that gives the best result. L -> M1 -> M2 -> ... wasm,where Mi are selected by the specific features used for a concrete program in L. All computations of efficiency should discount or take into account the use of specific libraries. For instance, numpy with python makes the speed difference between c and python smaller.