DIP 45 - approval discussion

[Benjamin Thaut]

Am 14.11.2013 20:54, schrieb deadalnix:
> On Thursday, 14 November 2013 at 13:31:30 UTC, Benjamin Thaut wrote:
>> Am 14.11.2013 11:28, schrieb Walter Bright:
>>>
>>> This of course means that functions may wind up going through the
>>> dllimport indirection even for calling functions in the same dll, but it
>>> should work.
>>
>> Also our suggested approach would not have this downside.
>>
>> Think about phobos. All of phobos and druntime will be littered with
>> export attributes. Do you really want all phobos and druntime from
>> within the same dll to go through dll indirections? And what would
>> happen when building phobos as static library? With your suggested
>> behavior (export=dllimport if not specified otherwise) this would mean
>> that even the phobos static library would have those indirections.
>
> This thread have reached some end.
>
> It has been shown in the beginning that linkers know how to get rid of
> the indirection here. If we are going to discuss the same thing again
> and again without even doing some experiment for the reality check, then
> we can stop right here.

No, linkers can not get of this indirection. Only whole program 
optimization can, and that won't happen in D (at least dmd) for quite 
some time. We had exactly that discussion in the old thread about the 
export attribute. See here: 
http://forum.dlang.org/thread/kvhu2c$2ikq$1@digitalmars.com#post-kvhu2c:242ikq:241:40digitalmars.com

But because Walter does not agree with the way we solved the problem in 
DIP 45 we have to go through everything again from the beginning.
And I'm certenly not going to accept a solution where we rely on some 
non implemented feature to remove indirections which will most likely 
not happen in the near future. The same already happend for virtual 
functions. The documentation states that the compiler might optimize 
them away, but in pratice this still does not happen, and most likely 
never will.

With DIP 45 we setteled for additional indirections to achive better 
usability and I'm ok with that. But what Walter suggests esentially 
means even more indirections and worse usability. And I'm not ok with that.

I also don't like that we have to go through everything again we already 
discussed in the old thread, but if Walter doesn't agree it has to be 
that way. So please try to contribute in a constructive manner, or leave 
out comments entierly.

Kind Regards
Benjamin Thaut