| Date: Wed, 20 Jun 2001 12:32:22 -0500 | |
| From: Vikram Adve <vadve@cs.uiuc.edu> | |
| To: Chris Lattner <lattner@cs.uiuc.edu> | |
| 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 | |