.NET assemblies and DLL rebasing

Question

According to this article rebasing is not necessary for .NET assemblies due to JIT compilation of the code. The article states:

\"JIT-compiled code does not hav

Answer 1

What OS are you running? I know that the vista and beyond introduced ASLR which randomizes the address space it loads dlls into. This happens for system dlls but not sure about .net - maybe something to look into.

Answer 2

CLR Loading mechanism uses LoadLibrary behind the scenes, so this is what you observe: 2 assemblies can't be loaded at the same address. Now what people often mean when they try to rebase a dll is to avoid the perf. hit of fix-ups, e.g. absolute addresses & function calls need to be "relocated" with the loaded base-address. CLR does not have this problem (not sure about static data in the application, which is the second part of those fix-ups, I would need to read up on this), because MSIL code is loaded on-demand when you call a function in the managed code. The MSIL then gets jitted and placed on the heap, a different one from normal object heap I believe, in the same manner CLR allocates and lays out new objects in your application.