The D ecosystem in Debian with free-as-in-freedom DMD

[Walter Bright via Digitalmars-d]

On 4/10/2017 5:59 AM, Matthias Klumpp wrote:
> You need to see here that D is not the center of the world and we will need to
> make it work nicely with the rest of the system. The technical policies work for
> everything else, so there is nothing that really justifies an exception for D
> here (if 10% of Debian's code was written in D and the Debian D team was really
> large we could maybe get one, but not the way it is now).
> And tbh, I think finding a good solution here is entirely possible.

I think it is possible, too, and thank you for your efforts helping us do this.

The ABI differences between the compilers is unfortunate, and is largely the 
result of historical accident.

The first problem is that my idea originally was for D to have its own function 
calling convention, which would free us to innovate to have a more efficient 
calling convention than the C one. This hasn't panned out in practice, and 
ldc/gdc decided to sensibly stick with the C ABI. At some point, we should just 
crowbar dmd to generate the C ABI, but this has its own problems - it'll break 
code that uses the inline assembler. No obvious solution there.

The next problem is that dmd occasionally changes the interface to the D 
runtime. Or more accurately, with about every release. This has not been an 
issue historically for us, as the two have always been a matched set. I'm a lot 
less sure how to deal with this. I also do not know how the gdc/lds druntime 
interfaces differ.