1*9880d681SAndroid Build Coastguard WorkerDate: Wed, 20 Jun 2001 12:32:22 -0500 2*9880d681SAndroid Build Coastguard WorkerFrom: Vikram Adve <[email protected]> 3*9880d681SAndroid Build Coastguard WorkerTo: Chris Lattner <[email protected]> 4*9880d681SAndroid Build Coastguard WorkerSubject: .NET vs. our VM 5*9880d681SAndroid Build Coastguard Worker 6*9880d681SAndroid Build Coastguard WorkerOne significant difference between .NET CLR and our VM is that the CLR 7*9880d681SAndroid Build Coastguard Workerincludes full information about classes and inheritance. In fact, I just 8*9880d681SAndroid Build Coastguard Workersat through the paper on adding templates to .NET CLR, and the speaker 9*9880d681SAndroid Build Coastguard Workerindicated that the goal seems to be to do simple static compilation (very 10*9880d681SAndroid Build Coastguard Workerlittle lowering or optimization). Also, the templates implementation in CLR 11*9880d681SAndroid Build Coastguard Worker"relies on dynamic class loading and JIT compilation". 12*9880d681SAndroid Build Coastguard Worker 13*9880d681SAndroid Build Coastguard WorkerThis is an important difference because I think there are some significant 14*9880d681SAndroid Build Coastguard Workeradvantages to have a much lower level VM layer, and do significant static 15*9880d681SAndroid Build Coastguard Workeranalysis and optimization. 16*9880d681SAndroid Build Coastguard Worker 17*9880d681SAndroid Build Coastguard WorkerI also talked to the lead guy for KAI's C++ compiler (Arch Robison) and he 18*9880d681SAndroid Build Coastguard Workersaid that SGI and other commercial compilers have included options to export 19*9880d681SAndroid Build Coastguard Workertheir *IR* next to the object code (i.e., .il files) and use them for 20*9880d681SAndroid Build Coastguard Workerlink-time code generation. In fact, he said that the .o file was nearly 21*9880d681SAndroid Build Coastguard Workerempty and was entirely generated from the .il at link-time. But he agreed 22*9880d681SAndroid Build Coastguard Workerthat this limited the link-time interprocedural optimization to modules 23*9880d681SAndroid Build Coastguard Workercompiled by the same compiler, whereas our approach allows us to link and 24*9880d681SAndroid Build Coastguard Workeroptimize modules from multiple different compilers. (Also, of course, they 25*9880d681SAndroid Build Coastguard Workerdon't do anything for runtime optimization). 26*9880d681SAndroid Build Coastguard Worker 27*9880d681SAndroid Build Coastguard WorkerAll issues to bring up in Related Work. 28*9880d681SAndroid Build Coastguard Worker 29*9880d681SAndroid Build Coastguard Worker--Vikram 30*9880d681SAndroid Build Coastguard Worker 31