Chris Lattner | d6be43e | 2001-06-24 02:01:31 +0000 | [diff] [blame] | 1 | Date: Wed, 20 Jun 2001 12:32:22 -0500 |
| 2 | From: Vikram Adve <vadve@cs.uiuc.edu> |
| 3 | To: Chris Lattner <lattner@cs.uiuc.edu> |
| 4 | Subject: .NET vs. our VM |
| 5 | |
| 6 | One significant difference between .NET CLR and our VM is that the CLR |
| 7 | includes full information about classes and inheritance. In fact, I just |
| 8 | sat through the paper on adding templates to .NET CLR, and the speaker |
| 9 | indicated that the goal seems to be to do simple static compilation (very |
| 10 | little lowering or optimization). Also, the templates implementation in CLR |
| 11 | "relies on dynamic class loading and JIT compilation". |
| 12 | |
| 13 | This is an important difference because I think there are some significant |
| 14 | advantages to have a much lower level VM layer, and do significant static |
| 15 | analysis and optimization. |
| 16 | |
| 17 | I also talked to the lead guy for KAI's C++ compiler (Arch Robison) and he |
| 18 | said that SGI and other commercial compilers have included options to export |
| 19 | their *IR* next to the object code (i.e., .il files) and use them for |
| 20 | link-time code generation. In fact, he said that the .o file was nearly |
| 21 | empty and was entirely generated from the .il at link-time. But he agreed |
| 22 | that this limited the link-time interprocedural optimization to modules |
| 23 | compiled by the same compiler, whereas our approach allows us to link and |
| 24 | optimize modules from multiple different compilers. (Also, of course, they |
| 25 | don't do anything for runtime optimization). |
| 26 | |
| 27 | All issues to bring up in Related Work. |
| 28 | |
| 29 | --Vikram |
| 30 | |