Issue 13093 - D ABI change for guaranteed efficient return of fixed size array

[9rnsr]

https://issues.dlang.org/show_bug.cgi?id=13093

[ghost]

@WalterBright @yebblies @ibuclaw @klickverbot:

This looks like a one-way street (IOW changing the ABI wording now means we can't backtrack later). So is this change ok?

[yebblies]

Well, we don't have a commitment to a stable ABI, so we can change it later. There's a good chance we will, to match the other compilers.

Anyway, I don't see a reason we would ever want to pass static arrays differently to structs, so this looks good.

[ibuclaw]

I don't have a commitment to follow what is written in abi.dd about extern(D).

1. Because it only describes what to do for Windows x86.
2. Since GDC and DMD have different mangling conventions (and runtime) for Windows x86 anyway, DMD guys can do what they want.

[ibuclaw]

As per @yebblies comment though, indeed int[3] is meant to be passed in the same way as struct { int a, b, c; }

[quickfur]

ping
Are we going ahead with this or not?

[dnadlinger]

Static arrays are supposed to be passed the same way as the equivalent struct, so the change is fine with me. Can't comment on whether this matches the implementation though, as the description only concerns Windows x86.