The compiler for GWT has done a lot of this for years (and it's functionality might have fed into closure). It's arguably different because it compiles from Ja

The compiler for GWT has done a lot of this for years (and it's functionality might have fed into closure). It's arguably different because it compiles from Java to Javascript as a first pass. It then does a lot of full-program optimization, including dead code elimination, lifting virtual method calls to static, inlining, reordering code to compress better, and analyzing the call graph to split code. (You have to be explicit about the split points in the Java code, so the analysis is mainly for doing the code splitting and for coalescing components that are are small or would force a lot of code into the common segment.) I believe GWT is moving on to closure for the latter optimization passes in future releases.