[LLVMdev] comments on Bug 1521 (Revamp LLVM by-value structure passing)

[Jonas Maebe]

On 26 jun 2007, at 15:30, Rafael Espíndola wrote:

> What I like about option 3 is that llvm continues to be unaware about
> the C struct passing convention. This is good since another FE (D,
> ADA) might want to have a different way of passing
> structs/objects/whatever. If we specialize on the C way of doing
> things I thing that other FE will have to come up with their own
> solutions and might not get as good code.

What you described is not "the C way" of doing things, but the ABI  
way. How arguments are passed should not be source language  
dependent, but calling convention dependent. I think that if other  
source languages require other calling conventions, either new  
calling conventions should be added to LLVM, or the frontends for  
those languages should emulate their particular requirements using  
tricks like your third proposal (and e.g. by turning parameter types  
implicitly into pointer types).


Jonas