Date: Wed, 20 Jun 2001 12:32:22 -0500 From: Vikram Adve To: Chris Lattner Subject: .NET vs. our VM One significant difference between .NET CLR and our VM is that the CLR includes full information about classes and inheritance. In fact, I just sat through the paper on adding templates to .NET CLR, and the speaker indicated that the goal seems to be to do simple static compilation (very little lowering or optimization). Also, the templates implementation in CLR "relies on dynamic class loading and JIT compilation". This is an important difference because I think there are some significant advantages to have a much lower level VM layer, and do significant static analysis and optimization. I also talked to the lead guy for KAI's C++ compiler (Arch Robison) and he said that SGI and other commercial compilers have included options to export their *IR* next to the object code (i.e., .il files) and use them for link-time code generation. In fact, he said that the .o file was nearly empty and was entirely generated from the .il at link-time. But he agreed that this limited the link-time interprocedural optimization to modules compiled by the same compiler, whereas our approach allows us to link and optimize modules from multiple different compilers. (Also, of course, they don't do anything for runtime optimization). All issues to bring up in Related Work. --Vikram