Pre-compilation for .NET Generics

The Microsoft .NET Common Language Runtime (CLR) supports pre-compilation in order to help avoid the slow application start-up times and unnecessarily high memory usage often associated with virtual machine (VM) execution, However, Version 2 of the .NET Common IL (CIL) also supports generics, i.e. type parameters for data and code, in part implemented using template-expansion techniques, and the use of dynamic compilation for generics would threaten the gains of pre-compilation. We describes techniques to support the pre-compilation of generic CIL code, resulting in the first language implementations to support the combination of dynamic loading, pre-compilation and typeparameterization over unboxed representations. We discuss the load-time techniques used to resolve potential duplication and optimizations based on “preferred pre-compilation modules”. We give performance results relating to code-size, code-duplication and start-up times as observed in our implementation of the techniques, aspects of which have been shipped in recent releases of v2.0 the Microsoft .NET CLR.