struct Location size

[Basile B.]

On Tuesday, 9 May 2023 at 00:24:44 UTC, Walter Bright wrote:
> This PR https://github.com/dlang/dmd/pull/15199 reduces its 
> size by 8 bytes, resulting in about 20Mb of memory savings 
> compiling druntime, according to @dkorpel.
>
> [...]
>
> So, for great glory, can anyone come up with a clever scheme 
> that uses only 32 bits?

Yes, call me a madlad but in styx the filename information is in 
the DMD equivalent of `Scope` (and the Loc is 2*32 bits, 
{line,col}). If you do the same in DMD you can reduce the size to 
32 bits, i.e 2*16 bits, {line,col}.

I'm not sure this would work for DMD but for styx the rationale 
was

1. in DMD the size of Loc is a known problem, that's why it's 
usually recommended to pass its instances by ref, let's not have 
the same problem.
2. there's much less Scopes than Loc.