Study: build times for D programs

[Peter Alexander]

On Tuesday, 24 July 2012 at 22:19:07 UTC, Jonathan M Davis wrote:
> On Tuesday, July 24, 2012 15:49:38 Nick Sabalausky wrote:
>> Yea. Programs using Goldie ( semitwist.com/goldie ) take a 
>> long time to
>> compile (by D standards, not by C++ standards). I tried to 
>> benchmark
>> it a while back, and was never really confident in the results 
>> I was
>> getting or my understanding of the DMD source, so I never 
>> brought it up
>> before. But it *seemed* to be template matching that was the 
>> big
>> bottleneck (ie, IIUC, determining which template to 
>> instantiate,
>> and I think the function was actually called "match" or 
>> something like
>> that). Goldie does make use of a *lot* of that sort of thing.
>
> I don't have any hard evidence for it, but I've always gotten 
> the impression
> that it was templates, mixins, and CTFE which really slowed 
> down compilation.
> Certainly, they increase the memory consumption of the compiler 
> by quite a
> bit. My guess would be that if we were looking to improve the 
> compiler's
> performance, that's where we'd need to focus. But we'd have to 
> actually profile
> the compiler on a variety of projects to be sure of that (which 
> is at least
> partially related to what Andrei is suggesting).
>
> - Jonathan M Davis

There's also the nasty O(n^2) optimiser issue.

http://d.puremagic.com/issues/show_bug.cgi?id=7157