Fragile ABI

[R Grocott]

Paulo -

Surely there are ways to work around the OS's native ABI, though, 
even from within compiled code?

Rewriting object vtables (etc.) might be a bit more involved than 
simple name mangling, but I'm almost certain it would be possible 
to implement it as part of druntime. The blog post which I linked 
describes one way to go about it.

Michael -

As far as I can tell, most of the performance cost in your idea 
comes from the additional level of indirection, since you store 
vtable offsets in a global variable which must be read before 
each function call.

This might just be wishful thinking, but would it be possible for 
druntime to write new vtable offsets directly into the program's 
machine code, at dynamic-link time? That would remove all of the 
run-time performance overhead, but, as I say, I'm not sure 
whether it's actually possible.

I think the biggest obstacle is that it would require the .text 
section (or equivalent) of the executable to be writable. I know 
that's possible on Linux, but I'm not sure whether the same is 
true for most other operating systems. I guess it might also be a 
security risk?